HUMAN PHYSIOLOGY; 
ANALYSIS AND DIGEST. 
FOR THE USE OF 
Medical Students and Practitioners. 
By John P. Schmitz, M. D., 
Professor of Physiology and Nervous Diseases in the California 
Medical College, San F'rancisco ; Member of the Eclectic 
Medical Society of the State of California ; Mem- 
ber of the San Francisco County Society 
of Physicians and Surgeons ; for 
MANY YEARS MEMBER OF THE 
State Board of Medi- 
cal Examiners. 
PUBLISHED BY THE AUTHOR: 
709-711 Twenty-first Street, San Francisco, Cal. 
1894. Entered according to Act of Congress in the year 1894, by 
John P. Schmitz, 
In the office of the Librarian of Congress, at Washington. 
All rights reserved. PREFACE. 
A new book on Physiology with such works as those of 
Landois, Dalton, Yeo, Kirkes, Chapman, Forster, Flint, 
Huxley and others before the public, would appear almost 
superfluous; yet this work may demonstrate that there are 
many points which even now require further elucidation. 
In any exposition in regard to physiology, it is difficult K 
arrange the subject-matters both in the order of their relative 
importance and of their logical sequence. In the following 
pages, however, we have endeavored to set forth in a brief 
yet clear and sufficiently extensive manner the more important 
points of physiological interest. The text is illustrated with 
many original diagrams. In preparing these illustrations 
no effort has been made to picture organs and their func- 
tions; they are merely designed to illustrate the text. 
Where it has been deemed advisable, sufficient anatomy is 
given to place the subjects in a clear light before the reader, 
without the necessity of reference to special text-books. This 
plan may assist even the physician in recalling forgotten 
parts of structures and of organic.functions. Furthermore, it 
is believed that this work, in its explanations of stimuli and 
sensation, will furnish the key to a better understanding of 
the physiological actions of remedies. 6 
PREFACE. 
The reader’s attention is especially called to the 'primary 
causes of respiration and circulation, the origin of the acid 
of gastric juice, sensations, the cause of capillary circulation, 
functions of nervous centres, mucous membranes, and albu- 
minoids, as set forth in this work. 
The science of physiology presents a well-nigh inexhaustible 
field of investigation, requiring careful study and deep 
thought. No one physiological subject can be singled out 
and an intelligent judgment passed upon it separately; the 
laws of life must be understood as an entirety. 
A glossary containing over 1000 technical medical terms, 
properly defined, has been appended, so that any educated 
person can understandingly read the book without the as- 
sistance of Latin and medical dictionaries. 
An exhaustive index of all the subject-matters in the 
book is also appended, so that any subject may readily be 
found in the text without loss of time. This may be an 
agreeable feature to the physician in refreshing his memory 
on special organic functions. The scientific physician cannot 
dispense with the book on the laws of life from his library 
table, any more than the lawyer can dispense with the book 
on the laws of the state from his table. The belief that after 
having once passed successfully the medical college the study 
of physiology is no further necessary, is surely a great mistake. 
It is hoped this work will prove not only helpful to the 
student, but also stimulate him to acquire a thorough knowl- PREFACE. 
7 
edge of the organic physical and physiological functions, and 
at the same time render his study a pleasurable one, on 
account of the condensed yet clear and comprehensive manner 
in which the subjects are treated. The scientific treatment of 
abnormalities of organic functions of the body can be ac- 
complished only through a thorough knowledge of the laws 
of life. 
The many medical students who, during their three-years 
course in the medical college, have listened to my lectures 
and recitations on physiology, are very gratefully remember- 
ed for their marked attention and gentlemanly bearing during 
the lecture hours. 
San Francisco, California, 
May, 1894. 
J. P. Schmitz. EXPLANATORY. 
* Stars indicate that the subject-matters are illustrated; the 
illustration may or may not be on the same page as given in 
the Contents. A separate and complete list of the illustrations, 
alphabetically arranged, will he found on page 19, et seq. 
All technical words in this book will be found, properly defined, 
in the Glossary at page 277, et seq. Also, a complete Index will 
be found at page 305, et seq. CONTENTS. 
INTRODUCTION. 
Physiology Defined, Page 23 
Organism, growth, structure, function, 23 
Organ defined, 23 
Animal, and vegetable life, 23 
Chlorophyll, 23 
Organisms, similarity of, 24 
Organisms, requirements of, 24 
Chemical elements of the body, 24 
Anatomic division of the body, 24 
System, apparatus, tissues, anatomical elements, . . . .24 
Cells, 25 
CHAPTER I. 
Nutrition, 26 
Origin of nutritious substances, 26 
Proximate principles, 26 
Albuminous (nitrogenous) matters, 26 
Starchy, saccharine, oleaginous matters, 26 
Inorganic matters, 26 
Coloring matters, 26 
Non-nitrogenous matters, 27 
Starch, sugar, 27 
Fats, 28 
Inorganic proximate principles, 29 
Water, 29 
Lime phosphate, 30 
Lime carbonate, 30 
Magnesium phosphate, 30 
Alkaline salts, 31 
Sodium chloride, 31 
Milk,* bread, meat, eggs, 32 
Amyloid compounds, 33 
Active Principles in Liquids and Solids, . . . . . .34 
Haemoglobin, 35 
Melanin, bilirubin, 35 
Biliverdin, urochrom, chlorophyll, 36 
Urea* 36 
Uric acid,* 37 
CHAPTER II. 10 
CONTENTS 
CHAPTER III. 
Mucous Membrane and Epithelium, Page 38 
Mucus, 39 
Endothelium, 42 
Epithelium, 42 
Epithelial cells, 42 
Digestion, 46 
Digestive organs, 46 
Food, 46 
Alimentary canal, 46 
Stomach, 47 
Chyme, . . .49 
Chyle, . • .50 
Gastric juice, 51 
Pepsin, 52 
Peptones, ’ 53 
Indigestion, 55 
Intestinal digestion, 56 
Intestinal walls, 57 
Villi, 57 
Glands of Brunner, 58 
Solitary glands, 59 
Peyer’s glands, 59 
Hunger and thirst, 61 
CHAPTER IV. 
Liver, Bile, and Pancreatic Juice, 62 
Bile-secreting apparatus, 62 
Hepatic artery and vein, 62 
Bile composition, 65 
Fatty degeneration of the liver, 65 
Liver sugar, 66 
Sugar of blood, 66 
Nerve-fibres supplying the liver, 67 
Lymphatics of the liver, 67 
Pancreas,* 67 
Pancreatic juice—composition, 68 
Vessels of the pancreas, 69 
Nerves of the pancreas, 69 
Spleen,* 69 
CHAPTER V. 
Secretion and Excretion, 71 
Secretion, 71 
Secreting follicles,* 72 
Secreted fluids, 73 
Excretion, . . . 74 
CHAPTER VI. CONTENTS. 
11 
The Absorbent System, Page 75 
Lymphatic system,* 75 
Chyle, 75 
Thoracic duct,* 76 
Lymph, 77 
Lymph glands, 78 
Osmosis, endosmosis, exosmosis, 78 
CHAPTER VII. 
The Blood, 79 
Red blood-corpuscles,* 79 
White blood-corpuscles,* 81 
Blood-plasma, serum, 82 
Blood disease, 84 
Blood-corpuscles—composition, 85 
Coagulation of blood, 86 
Thrombus, clots,* S6 
CHAPTER VIII 
CHAPTER IX. 
The Circulation, 88 
Heart, arteries, capillaries, veins, 88 
Blood circulation,* 89 
Heart structure,* 90 
Heart action, 91. 
Cause of the heart’s action, 92 
Reflex action of the heart, 93 
Syncope, 94 
Aorta,* arteries, arterial walls, 94 
Arterial pulsation, 95 
Pulse rate, 96 
Veins, 96 
Veins—valves,* 97 
Capillary circulation,* 97 
Capillary circulation peristalsis, 98 
Capillary action, 99 
CHAPTER X. 
Respiration, 101 
Trachea,* 101 
Lungs,* . 101 
Nerve-fibres of the lungs, 102 
Phrenic nerve, 103 
Respiratory centre or vital point, 103 
Lymphatics of the lungs, . 103 
Blood of the lungs, 103 
Pulmonary artery,* 104 
Alveoli,* 104 
Exchange of gases in the lungs,* 104 12 
CONTENTS. 
Pulmonary veins,* Page 105 
Haemoglobin, 106 
Haematin, 106 
Air required, 107 
Air changes, 108 
Carbonic acid, 108 
Secretion and excretion of carbonic acid, 109 
Carbonic acid, use of, 110 
Oxygen, use of, 110 
Theory of external organic sensation, Ill 
Respiratory activity, 112 
Carbonic acid stimulus, . . . . • 113 
Physiological process of lowering temperature, .... 114 
Oxidation (a misnomer), 115 
Production of carbonic acid, 116 
Dyspnoea, ... 116 
Respiration of the newly born, 117 
Temperature, 118 
Heat defined; heat produced or diminished 118 
Temperature of arterial and venous blood, 119 
Temperature, degrees of, 120 
Thermometer,* 120 
Temperature maintained, 121 
Harmonious action of respiration and pulsation, .... 121 
Abnormally high or low temperature, danger of, ... 122 
Effect of perspiration on temperature, 123 
CHAPTER XI. 
Nervous System, 124 
Cerebro-spinal system, 124 
The brain,* 125 
Brain centres,* 125, 130 
Brain composition, 127 
Brain ventricles,* 127 
Cerebrum,* 127 
Circle of Willis,* 128 
Function of cerebral convolutions, 129 
Memory, reason, judgment—definitions, 129 
Insanity defined, 129 
Soul defined, . 129 
Corpora striata,* 130 
Optic thalamus,* 130 
Corpora quadrigemina,* 131 
Pineal gland,* 131 
Crura cerebri,* 131 
Valve of Vieussens, 132 
Pons Varolii,* 132 
Cerebellum,* 132 
CHAPTER XII. 13 
CONTENTS. 
Medulla Oblongata,* Page 134 
Olivary body,* 134 
Fourth ventricle,* 134 
Nerve-fibres—origin in the medulla,* 135 
Centres in the medulla oblongata, 135 
Respiratory centre, 136 
Injury to the medulla, results of, 136 
CHAPTER XIII 
CHAPTER XIY 
Nervous Centres and Reflex Action, 138 
Nervous centre-cells,* 138 
Sensation centres, known or unknown 139 
Reflex action,* 139 
Sensation defined, 139 
Property defined, 139 
Irritability defined, 140 
Excitability defined, 140 
Co-ordination, 140 
Sympathy, 141 
Reflex, control of, 141 
Abdominal, plantar, and pupil reflexes, 142 
CHAPTER XY. 
Nerve-fibres and their Terminals, ....... 143 
Nerve-fibres, size of, 143 
Medullated and non-medullated fibres, 143 
Nerves,* Neurilemma* 143 
Inosculation of nerve-fibres with nerves,* 144 
Nerve-fibre branches,* 145 
Tactile corpuscle,* 145 
Pacinian bodies,* 146 
Terminal bulbs,* 147 
Terminal plates,* 147 
Irritability of nerve and muscular fibres distinct, .... 148 
Impulses, speed of, 149 
Electricity, action of, 149 
Faradic current, action of, 150 
CHAPTER XYI 
The Spinal Column,* 151 
Division,* power or strength of the spinal column, .... 151 
Spinal cord,* 152 
Cells of the cord,* 152 
Spinal nerves,* . 153 
Law of Waller, 153 
Spinal cord, function of, 154 
Centres of the cord, 155 
Section of the cord, effect of, 155 
Urinary bladder, sphincter muscles, 156 14 
CONTENTS. 
Reflexes of the cord Page 157 
Paraplegia, hemiplegia, 157 
Strychnine, action of the cord, 157 
Tetanic spasms, 157 
Hydrophobia, tetanus, epilepsy, hysteria, 158 
Meninges, 158 
CHAPTER XVII. 
Tiie Sympathetic System,* 160 
Ganglia,* 160 
Nervous plexus,* 161 
Functions of the sympathetic system, 162 
CHAPTER XVIII. 
The Senses, 163 
Sense-organs, 163 
Sight, hearing, smell, taste, touch, 163 
Common sense, 164 
External sensation, . . . 165 
Vital organic representation, 165 
The soul present in every part of the body, 166 
Exterior sensation in the brain denied, 166 
Consciousness defined, 166 
Imagination defined, 167 
Estimative faculty defined, 167 
Sensitive memory defined, 168 
Reminiscence, 168 
Sensation requires three distinct elements, 168 
Sensation, modus operandi, 169 
Cranial Nerves,* 170 
Sensory, motor, and mixed nerves, 170 
Olfactory nerve,* 171 
Olfactory bulb,* 171 
Optic nerve,* 172 
Oculomotorius nerve,* 174 
Trochlearis (Patheticus) nerve,* 174 
Trigeminus nerve,* 175 
Gasserian ganglion* 175 
Ophthalmic nerve,* 176 
Superior and inferior maxillary nerves,* 176 
Abducens nerve,* 177 
Facial nerve,*. 178 
Auditory nerve,* 180 
Glosso-pharyngeal nerve,* . . , 181 
Tongue nerve supply, 182 
Sense of taste, 182 
Pneumogastric nerve,* 183 
Spinal accessory nerve,* 184 
Hypoglossal nerve,* 186 
CHAPTER XIX. CONTENTS. 
15 
The Eye and the Sense of Sight, ... • Euge 187 
Eyeball* 187 
Sclerotic coat, cornea, and choroid coat,* 187 
Hyaloid membrane,* 187 
Vitreous body or humor, 187 
Aqueous humor, 188 
Anterior and posterior eye chambers,* 188 
Ciliary muscle,* 188 
Ciliary and suspensory ligaments,* 189 
Canal of Petit,* 189 
Pupil, 189 
Iris,* 189 
Pupil—contractor and dilator centres, 190 
Nerves of the iris, 190 
Crystalline lens,* 191 
Ciliary processes,* 191 
Retina, rods, and cones,* 191 
Optic nerve,* 192 
Movements of the eyeball, 192 
Nerves and arteries of the eyeball, 192 
Eyelids, 192 
Lachrymal and Meibomian glands, 193 
Accommodation of the eye, 193 
Distance of vision, 194 
Artificial lenses,* 195 
Light, sight, 196 
Light, velocity of, 196 
Color-blindness, 197 
Emmetropic, hypermetropic, and myopic* eyes, .... 197 
Diplopia and presbyopia,* 198 
Hemeralopia and snow-blindness, 199 
CHAPTER XX. 
The Ear and the Sense of Hearing, 200 
External ear,* 200 
Membrana tympani,* 201 
Middle ear, or tympanum, 203 
Malleus* and incus* bones, 204 
Stapes,* 205 
Muscles of the middle ear, 205 
Eustachian tube,* 205 
Internal ear,* 206 
Vestibule,* 206 
Otoliths and otoconia,* 207 
Semicircular canals,* 209 
Vertigo, 209 
Equilibrium, 209 
Osseous cochlea,* 210 
Modiolus,* 210 
CHAPTER XXI 16 
CONTENTS. 
Scala vestibuli, scala tympani, and scala media,* . . . Page 211 
Organ of Corti,* 211 
Membrana basilaris,* 212 
Sound, 212 
Vibration, 213 
Wave-length, 213 
Loudness and pitch of sound, 213 
Quality of sound, . . . . , 214 
Resonance, 214 
Hearing, 215 
CHAPTER XXII. 
The Voice and Speech, 217 
Vocal cords,* 217 
Muscles of the vocal organs,* 218 
Vocalization, 218 
Vocal resonance, 219 
Limits of the human voice, 219 
Limits of hearing musical sounds, 219 
Action of the vocal cords, 219 
Change of voice, 219 
Vocalization, 220 
Articulation, 220 
Speech defined, 220 
Speech centre, 220 
Sensory and motor aphasia, 220 
Ataxic aphasia, 221 
Stammering and stuttering, 221 
CHAPTER XXIII. 
"The Skin, 222 
Functions of the skin, 222 
Epidermis and cuticle,* 222 
Color of different human skins, 222 
Sectional view of the skin,* 223 
Dermis,* 224 
Papillae of the skin,* 224 
Corium, 225 
Muscular fibres of the skin,* 226 
Arrectores pilorum,* 226 
Tension of the skin, 226 
Subcutaneous tissue, 226 
Sudoriparous glands, perspiration, 227 
Sebaceous glands,* 228 
Appendages of the skin, 229 
Hair,* 229 
•Gray hair, 231 
Blood-vessels, nerves, and lymphatics of the skin, .... 231 
Haemorrhage of the skin, 231 
-Rails, 231 CONTENTS. 
17 
CHAPTER XXIV. 
The Kidneys,* Page 233 
Cortical and medullary substances,* 233 
Renal pyramids,* 234 
Glomerules,* 234 
Malpighian bodies,* 235 
Urine—composition, 236 
Urea,* 237 
Uric acid,* 238 
Bladder, 239 
Incontinence, and retention of urine, 239 
Wolffian bodies, 239 
Bright’s disease, 240 
Suprarenal capsule, 240 
Addison’s disease, 240 
The Muscular Tissues, 241 
Striated muscular fibres,* 241 
Perimysium, externum and internum,* 241 
Muscular fasciculi,* 242 
Sarcolemma, . 242 
Tendon, 242 
Unstriped muscular fibre,* 243 
Irritability of muscles, 244 
Elasticity and tonicity of muscles, 245 
Contractility of muscles, 246 
Muscular action, 248 
Metabolism—anabolism and katabolism, 248, 249 
Involuntary muscles, 249 
CHAPTER XXV. 
CHAPTER XXVI. 
Reproduction, 251 
Fission, Gemmation, and Fecundation 251 
Uterus,* 251 
Fallopian tubes,* 253 
Vagina, 253 
Round ligaments,* 254 
Broad ligaments,* 254 
Uterine arteries, 254 
Uterine nerves, 255 
Uterine lymphatics, 255 
Ovary,* 256 
Ovulation, 256 
Corpus luteum,* 256 
Testicle and spermatozoa,* 258 
Fecundation, 259 
Impregnation,* 259 
Ova,* 259 18 
CONTEXTS. 
Germinal membrane,* Page 260 
Blastoderm, 260 
Ectoderm, mesoderm, entoderm, 260 
Decidua,* 261 
Chorion, 261 
Placenta,* 261 
Extra-uterine pregnancy, 261 
Graviditas in substantia uteri, 262 
Twin pregnancy, 262 
Mamma,* 262 
Nausea and vomiting during pregnancy, 264 
Moles and hydatids, 264 
Foetal circulation,* 265 
Menstruation, 266 
Entozoa and infusoria, 269 
Life functions, termination of, 269 
Plant reproduction, 269 
Miscellaneous, 270 
Connective and fibrous tissues, 270 
Cartilage, bone, and periosteum, 270 
Gangrene, 271 
New formations—cancer, tumor, 271 
Fatty degeneration, 272 
Dissolution of the body, 273 
Spontaneous generation, . . 273 
Ptomaines, 273 
Infection and contagion, 274 
Ether, 274 
Still-born, 275 
Artificial respiration, 275 
CHAPTER XXVII. ILLUSTRATIONS. 
Abducens nerve, Pages 135, 178 
Aeration of the blood, . . . 104 
Alimentary canal, 47 
Alveolus, 104 
Anterior pyramid, 126, 135 
Aorta, 90 
Aortic plexus, 161 
Artery ligated, 86 
Auditory canal (internal) 180, 201, 202 
Auditory nerve, 135, 180, 201, 208 
Auditory nerve centre, 180 
Auricles of the heart, 90 
Axis-cylinder process 138 
Bile duct 68 
Blood circulation, 89 
Blood clot, 86 
Blood-corpuscles (red and white), 80 
Brain, 125, 126, 130,135 
Brain—anterior lobe, 126, 135 
Brain centres, 126, 130 
Brain convolutions, 125, 126, 130 
Brain hemisphere, 125, 130 
Brain—middle lobe, 126, 135 
Brain—motor nerve-fibre tract, 130 
Brain—posterior lobe, 126, 135 
Brain—sensory nerve-fibre tract, 130 
Brain ventricles, 127 
Broad ligaments, 253 
Bronchi, 102 
Bronchiolus, 104 
Brunner’s glands, 58 
Capillary circulation, 98 
Cardiac plexus, 16 L 
Cerebellum, 126, 135 
Cerebrum, 126 
Ciliary processes, 188 
Ciliated columnar epithelial cells, 43 
Circle of Willis, 128 
Cochlea, 202, 210, 211 
Columnar epithelial cells, 43, 44 20 
ILLUSTRATIONS. 
Commissure fibres tract, Page 130 
Corpora quadrigemina, 126, 130 
Corpus callosum, 125 
Corpus striatum, 126, 130 
Cranial nerves, 135, 171 to 186 
Crus cerebri, 126, 130, 135 
Crystalline lens, 188 
Crystallized sodium chloride, 31 
Ductus communis choledochus, 63 
Ear, external, 201 
Ear, internal, 201, 202, 208 
Ear, middle, 201, 202 
Epigastric plexus, 161 
Epithelial cells, 43, 44, 45 
Eyeball, 188 
Eyeball (abnormal), 198 
Facial nerve, 135, 179 
Fallopian tubes 253 
Fifth ventricle 127 
Foetal circulation, 265 
Follicles of Lieberkiihn, 58 
Follicles (secreting), 72 
Fourth ventricle, 127 
Gall bladder, 63 
Gasserian ganglion, 161, 176 
Gastric vein, 63 
Gland, mammary, 263 
Glands, Brunner’s, 58 
Gland, Pineal, 126, 130 
Glands, sebaceous, 223, 229 
Glands, sudoriparous, 223 
Glandular epithelial cells, 45 
Glomerules of the kidneys 235 
Glosso-pharyngeal nerve, 135, 181 
Goblet epithelial cells, 44 
Hair, 223, 229 
Heart, cavities of, 90 
Hepatic artery, 63 
Hepatic blood supply, 63 
Hepatic vein, 63 
Hypogastric plexus, 161 
Hypoglossal nerve, 135, 186 
Inosculation of nerve-fibres with nerves, 144 
Iris 188 
Kidneys, 234 
Lateral ventricles, 127 
Lenses (artificial), 
Lieberkuhn’s follicles, 58 
Liver, 63 ILLUSTRATIONS. 
21 
Longitudinal fissure, Pages 125, 130 
Lungs, 102 
Lymphatics, 76 
Malpighian bodies, 235 
Mammillary eminences, 135 
Mammary gland, 263 
Medulla oblongata, 126, 130, 135 
Mesenteric veins, inferior and superior, 63 
Motor nerve-fibre tract, 130 
Mucous membrane, 58, 72 
Muscle structure, 242 
Muscular coat of the mucous membrane, 58 
Muscular fibres—structure, 243 
Nerve-fibres, 144, 145 
Nerve-fibres—tract, 130 
Nerve structure, 144 
Nerves, cranial, 135, 171 to it>o 
Nervous centre-cells, 138 
Nervous plexus, 161 
Neurilemma, 144 
Oculomotorius nerve, 135, 174 
Oculomotorius nerve-fibre tract, 130 
Oil globules in cow’s milk, . .28 
Olfactory bulb, 126, 130, 171 
Olfactory nerve, 135, 171 
Olivary body, 126, 135 
Ophthalmic ganglion, 161 
Optic nerve, 135, 173, 188 
Optic nerve-fibre tract, 130 
Optic thalamus, 126, 130 
Organ of Corti, 211 
Otic ganglion, 161 
Ovary, 253, 256 
Ovum, 256, 259 
Pacinian bodies, 146 
Pancreas, 68 
Pineal gland, 126, 130 
Pneumogastric nerve (vagus), 135, 184 
Pons Yarolii, 126, 130, 135 
Portal vein 63 
Pulmonary artery and vein, 90 102 
Pyramid, anterior, 126, 135 
Receptaculum chyli, 76 
Reflex action, process of, 140 
Renal plexus, 161 
Restit'orm body, 126, 135 
Retina, 138, 191 
Round ligaments, 253 
Schneiderian membrane, 171 22 
ILLUSTRATIONS. 
Sebaceous glands, Pages 223, 229 
Secreting follicles, 72 
Semicircular canals, 202, 208 
Semilunar ganglion, 161 
Sensory nerve-fibre tract, 130 
Serous coat of the mucous membrane, 58 
Skin, 223 
Spermatic plexus, 161 
Spermatozoa, 258 
Spheno-palatine ganglion, 161 
Solar plexus, 161 
Solitary glands, 59 
Spinal accessory nerve, 135, 185 
Spinal column, 151 
Spinal cord, 152 
Spinal nerves, 153 
Spleen, 63, 68 
Splenic vein, 63 
Squamous epithelial cells, 44 
Stomach, 63 
Submaxillary ganglion, 161 
Submucous coat of the mucous membrane, 58 
Sudoriparous glands, 223 
Sympathetic ganglion, 161 
Sympathetic system, 161 
Tactile corpuscles, 145 
Taste centre, 181 
Temperature scale, 120 
Terminal bulbs and plates, 147 
Thermometer, 120 
Third ventricle, 127 
Thoracic duct, 76 
Thrombus, 86 
Trachea, 102 
Trigeminus (trifacial) nerve, 135, 176 
Trochlear nerve, . 135,175 
Urea (crystallized), 237 
Uric acid (crystals), 239 
Uterus and its appendages, 252, 253 
Valves of the heart, 90 
Valves of the veins, 97 
Valvulae conniventes, 59 
Venae cavae 90 
Ventricles of the brain, 127 
Ventricles of the heart, 90 
Vertebrae, 151 
Vestibule of the ear, 202, 208 
Villi of the intestine, 58 
Villus, 57 
Vocal chords, 218 PHYSIOLOGY; ANALYSIS and DIGEST 
INTRODUCTION. 
Physiology is the science of the laws of life and functions 
of living organisms. 
An Organism consists of a combination of organs, and has 
specific functions. In structure it is capable of performing actions 
and producing effects not only by itself and within itself, but also 
on matter external to and outside of itself. An Organ is a part 
of an organism, and its action is its function. 
The organic world includes both animal and vegetable life, with 
their component and physical properties, chemical composition, and 
vital phenomena. Animal as well as vegetable life depends upon 
the action of its individual organs, distinct but mutually combined 
and dependent. 
Organic bodies differ from inorganic by the introduction, assimi- 
lation, combination, and reconstruction of new or fresh matter. 
Certain inorganic substances aggregate to themselves fresh material, 
enlarging in size and quantity, thus showing a quasi-assimilation; 
but they do so only by the addition of particles of matter to their 
exterior. The organic living structure grows by the addition of 
new matter not only to its surface, but throughout its entire mass; 
and at the same time it continually changes—decay and repair go- 
ing hand in hand. As soon as the mutual dependence of the dif- 
ferent organs in an organized body ceases, it becomes like an 
inorganic body, the only force that keeps it in form being cohesion. 
The vegetable or plant, through its chlorophyll, or green coloring 
matter, decomposes the carbonic acid, ammonia, and water, which 
were absorbed by its roots and leaves, and utilizes them as food. 
There is a chemical change effected under the influence of solar 
light, the carbon of the carbonic acid becoming fixed in the 24 
INTRODUCTION. 
structure of the plant, and the oxygen exhaled. Kirkes states 
that “ animals cannot thus use inorganic matter, and never exhale 
oxygen as a product of decomposition.” 
Organisms differ widely, except in cellular assimilation for nutri- 
tion and repair. In their tissues the vital phenomena are per- 
formed by living cells, acting independently in response to stimuli; 
and for proper action require a certain degree of warmth and 
moisture, without which chemical interchanges cannot proceed, the 
organism becoming either inactive or destroyed. 
As this work is designed to elucidate the principles of Human 
Physiology only, the subject-matters of the following pages are, 
therefore, restricted to this branch of physiological science, as far 
as it is deemed compatible with fullness of elucidation. 
About fifteen of the elements known to chemists take part in 
making up the tissues of the human body, the majority being pres- 
ent in small and varying quantities only. Four elements, how- 
ever— hydrogen, oxygen, nitrogen, and carbon—occur always in 
large quantities, constituting 97 per cent of the animal frame—hy- 
drogen, oxygen, and carbon being the most constant and abundant. 
The human body, anatomically, is divided into four parts— 
head, neck, trunk, and extremities, each of which contains many 
different organs; viz., in the head: brain, eyes, ears, etc.; in the 
trunk: heart, lungs, liver, kidneys, spinal cord, etc.; in the extrem- 
ities, and body, every bone and muscle constitutes a distinct organ. 
A System consists of a combination of several organs, similar 
in texture, but scattered throughout the body— as the arterial, 
muscular, osseous, and nervous systems. 
An Apparatus is formed by the combination of entirely differ- 
ent organs; for instance, the circulatory apparatus is formed by the 
heart, arteries, capillaries, and veins. 
By Tissues we understand the texture or grouping of two or 
more different anatomical elements interwoven into each other, of 
which any part of the body is composed. 
An Anatomical Element is the smallest natural division of 
the organism. If the anatomical element—e. g., a blood corpuscle, 
muscular fibre, or an epithelial cell—be separated from the organ- 
ism, and further broken up, it loses its identity and function. The 
union of these elements constitutes the tissues; consequently, all 
parts of the human frame are made up of anatomical elements, 
forming organs, systems, and apparatuses connected with each other. 
Each anatomical element, wherever situated in the body, possesses INTRODUCTION. 
25 
the property of becoming excited by a stimulus proper and essen- 
tial to it. Herein lies the great secret of vitality, or life. 
A Cell is a nucleated mass of protoplasm, in the form of a small 
vesicle, composed of a jelly-like or somewhat fatty substance. In 
all kinds of tissues the function of cells differs; some stimulating, 
while others secrete, absorb, repair, or reproduce. A cell is the first 
noticeable formation to propagate vital phenomena. Its function 
is not only assimilative, enabling it to increase in size, but also 
contractile, originating vital energy within itself and transmitting 
it to other tissues. That cells differentiate by a distinct investing 
envelope, termed cell-wall, or cell-membrane, has not been con- 
firmed. Cell-reproduction is by fission or division. Each cell 
is an entity. In reproduction, its tissue, nucleus, and nucleolus 
(protoplasm) elongate and divide into two halves; each forming a 
complete cell. CHAPTER I. 
NUTRITION. 
Nutrition is the assimilation of nourishment in the body. 
The nutritive substances are derived from proximate principles 
already existing in animal and vegetable foods, which are adapted 
to enter into the composition of the different parts of the body. A 
proximate principle is a compound of elements existing in the animal 
or vegetable, solid or fluid, and which can be extracted without altering 
or destroying its properties. The most necessary of these for nu- 
trition are:— 
1. Albuminous (Nitrogenous), of organic origin, and derived from 
both animal and vegetable foods. 
2. Starchy, Saccharine, and Oleaginous (Non-nitrogenous), also of 
organic origin, and derived from both animal and vegetable foods. 
3. Inorganic (water and saline matter), derived from liquids and 
solids. 
The Coloring Matter, consisting of nitrogenous compounds, is be- 
lieved to originate in the body. 
Albuminous, or Nitrogenous, substances are of great im- 
portance for animal tissues and fluids, no food being nutritive with- 
out them. Albuminous matters are called nitrogenous proximate 
principles because they contain nitrogen in addition to carbon, hy- 
drogen, oxygen, and sulphur. Owing to the nitrogen contained, 
they differ from the non-nitrogenous (starch, sugar, and fat). The 
principal food substance of muscular tissue is its albuminous matter, 
and musculin, similar in composition. Albumen exists naturall}T 
in the most pure state in the “white” of an egg. Albuminous matter 
refers to animal and vegetable food containing some albumen 
mingled with other nutritive substances; while Albuminose is the con- 
verted albuminous matter, liquefied in the stomach; it is capable of 
passing through animal membranes, which pure albumen cannot 
do. Albuminous substances are hygroscopic—i. e., they contain 
moisture—and may, therefore, on evaporation of the moisture, be- 
come solidified; however, if brought again in contact with moisture 
they will absorb liquid and swell, but never go beyond the weight NUTRITION. 
27 
or quantity originally associated with them. In addition to being 
hygroscopic, the albuminous proximate principles coagulate, but 
when coagulated cannot resume their original condition. In regard 
to coagulation, the peculiar chemical characteristics of albumen, 
fibrin, and casein are distinguishable as follows: Albumen coag- 
ulates when boiled; casein, when in contact with an acid; fibrin, 
when gradually withdrawn from the blood-vessels and exposed to 
the air. When albumen coagulates, its properties are permanently 
changed; it assumes a solid form, but retains the same quantity of 
water as before. Vegetable albumen exists in all vegetables, and 
forms their most essential constituent when used as food. In one 
thousand parts of human blood there are about 75 parts of albumen, 
which, by its presence in the blood, has the physiological property 
of mutually exciting in other proximate principles catalysis, or 
catalytic transformation—i. e., it dissolves, destroys, or changes 
them into other forms. The albumen, too, uses itself up during 
these transforming processes. 
Non-nitrogenous proximate principles are divided into two 
groups—carbohydrates (starch and sugar), and hydrocarbons (fats); 
the latter including all varieties of oleaginous matter. 
Starch.—During mastication starchy matter is partly converted 
by the saliva into glucose, which has during digestion the same sig- 
nificance as sugar. Starch, sugar, and fat are termed non-nitrog- 
enous because they contain no nitrogen, but consist of carbon, hy- 
drogen, and oxygen—carbon forming 44 to 84 per cent. Starchy 
substances are converted into sugar by the pancreatic juice also, 
during digestion. The necessity and desire for vegetable food is so 
great that restriction to a diet of animal food would surely in time 
prove fatal to the human body. Saccharine and oleaginous sub- 
stances are necessary, and found together in most vegetable food; but 
neither is alone sufficient for nutrition. In a short time health 
would fail without the albuminous and fatty proximate principles. 
Sugar.—The sugar in the food, as well as that formed in the 
liver, disappears by decomposition in the animal fluids; normally, 
it does not appear in any of the excretions. Sugar contains much 
carbon, which may be demonstrated by placing a small quantity 
of sugar on a hot stove; the water evaporates and the carbon 
remains; but the sweetness of the sugar is destroyed, as its mole- 
cules are split up, the atoms of hydrogen and oxygen having sepa- 
rated from the carbon. Sugar of milk and liver sugar originate in 
the body; the cells of the mammary gland and those of the liver, 28 
NUTRITION. 
respectively, having the function of effecting the union of the proper 
number of atoms of carbon, hydrogen, and oxygen into molecules 
of sugar. Liver sugar is found in the substance of the liver and 
in the blood of the hepatic veins. 
Fats.—As a general rule, the oleaginous matter in animal sub- 
stances is found in distinct masses or globules suspended in the 
serous fluids; interspersed in the interstices between the anatomical 
elements; in the interior of cells; or deposited in the substance of 
fibrous membranes. (Even in vegetable tissue, oil is always depos- 
ited in distinct drops or globules.) Fat or oily matters are neces- 
sary ingredients of food; they cannot be adequately substituted by 
starch and sugar. The production of fat in the body requires a 
supply of proper materials. Sometimes in the animal economy, 
when emaciation takes place, the oil partly disappears from the 
cavity of the adipose vesicle (fat-cell) and a watery serum fills that 
portion of the cell, but the serous and oily fluids remain distinct in 
the different parts of the vesicle. In milk the oily matter is in larger 
globules and in greater quantity than in chyle. In cow’s milk the 
oil, or milk-globules (Fig. 1), have a pasty consistency, on account 
of the larger quantity of palmatin in proportion to the olein, and 
when churned their combination 
forms butter. The fat of the body 
is partly taken in with food and 
partly formed in the body by the 
metamorphosis of other (not fatty) 
proximate principles; possibly, 
also, by the transformation of 
starch and sugar, as starch dis- 
appears from oil-seeds when ripe. 
The important physiological fact 
in relation to amylaceous, saccharine, and oily substances, as to 
their source and final destination, is that they are of organic origin, 
appearing first in vegetable growths. They are also derived, to a 
certain extent, from other organic materials in the bodies of ani- 
mals, and continue to be formed when no similar food has been 
taken. The fixed oils, of either animal or vegetable origin, consist 
of three oleaginous ingredients—olein, stearin, and palmatin. 
The olein is the liquid portion and the distinctive proximate prin- 
ciple, and is found mostly in animal oils or fats; the other two, 
stearin and palmatin, are more solid ingredients. Stearin is most 
abundant in tallow and other animal fats; palmatin, principally 
Fig. 1. 
Oil Globules in Cow’s Milk. NUTRITION. 
29 
in palm oil, cocoanut oil, human fat, and butter. Fat when taken 
with food is not altered in the stomach, except that it is freed 
from its enclosing membranes, and, entering the duodenum, the 
greater part is then converted into a fine emulsion under the influ- 
ence of the pancreatic juice. It is then ready to be absorbed 
by the lacteals, and enter the circulation, where its essential 
characteristics are destroyed through a series of changes. rlhe 
transformation of fat in the vital economy evokes great activity of 
atoms and molecules, thereby producing heat. Fat has a low 
power of conducting heat, so that the fat deposited under the skin 
serves to retain the heat produced in the body. The further use of 
fat in the vital economy is to fill up spaces, and, as a soft, yielding 
material, to serve either as a bed for delicate structures or as 
an envelope for them. In health a moderate quantity of fat is 
appropriated by the organism, but, when introduced with the food 
in greater quantity than the absorbents are capable of taking up, 
then the surplus passes out with the feces and a small quantity 
with the sebaceous secretions. 
Starch, sugar, and fat, after serving the purposes intended in the 
body, become transformed and decomposed, and are finally ex- 
pelled in the form of carbonic acid and water. 
Inorganic Proximate Principles are compounds of chem- 
ical elements. Those most commonly found in the body are water, 
sodium and potassium chlorides, phosphates, sulphates, carbonates, 
lime phosphates and carbonates, and magnesium phosphates and 
carbonates. The alkaline carbonates, phosphates, and sulphates 
are formed partly within the system during the decomposition of 
organic matter. 
Water is not changed in the body, but absorbed, circulated, de- 
posited, liberated, and expelled unchanged; though it remains nec- 
essarily present in sufficient quantity. It enters into the compo- 
sition of every fluid and solid tissue of the body, and the system 
suffers more quickly from want of liquid than from want of solid 
food. Water is a very important and essential ingredient, because 
it holds the particles of solid material in fluids in solution, facil- 
itates their endosmosis and exosmosis, enables nutritious elements 
to find their way into the blood, to penetrate the substance of the 
solid organs, and permeates every part of the body. It brings the 
organic and inorganic materials in contact, thereby enabling them 
to assume new forms. Through its agency chemical changes are 
accomplished in the various organs; for even the most solid parts 30 
NUTRITION. 
of the body contain water, which, when evaporated, reduces their 
weight. About sixty per cent of the entire weight of the body is 
water, derived from without either in drink or food. About 2000 
grammes (nearly four and a half pounds) of water per day is in- 
troduced into the system of an adult. Water passes off with the 
urine, feces, and by the lungs and skin. In 100 parts of water 
passing from the body, the lungs give off by exhalation about 20 
parts; the skin, by perspiration, 30; the kidneys, with the urine, 46; 
the other 4 parts passing off with the feces, thereby rendering an 
almost continuous supply of water necessary. 
Lime Phosphate is contained in all animal and vegetable 
foods, and all animal solids and fluids of the body hold it as a 
constituent element. In quantity it ranks next to water, and is 
present in greater quantity than any other mineral salt, forming 
more than one-half of the substance of bone. It is not soluble in 
water, but is held in solution in the blood by albuminous substances. 
The lime phosphate imparts rigidity to the solid tissues, the stiff- 
ness or hardness of bones and teeth being due to its presence. It 
may be extracted by macerating bones in dilute muriatic acid, after 
which, while the organic material retains its form, the bones are, 
however, capable of being flexed or'twisted. The peculiarity of lime 
phosphate is its combination internally with animal matter of all 
kinds of tissues, similar to the manner in which the coloring matter 
unites with the other ingredients in colored glass, the lime phosphate 
still retaining its original character and composition. If in child- 
hood ossification does not properly proceed on account of the 
insufficiency of lime phosphate, rhacliitis, or rickets, results, and 
the spine and bones become distorted. In adult life an insufficient 
supply of lime phosphate causes morbid softening of bones, termed 
osteomalacia. In urine, lime phosphate is held in solution by acid 
bi-phosphate. Whenever urine is rendered alkaline by the ad- 
dition of soda or potassa, the earthy phosphates, of which lime 
phosphate is one, are precipitated in the form of a turbid white 
sediment. 
Lime Carbonate, like lime phosphate, is found in all animal 
solids and fluids, its proportion compared with lime phosphate 
being about one-seventh by weight. The carbonate is held in 
solution in fluids by virtue of the presence of alkaline chlorides, 
such as the sodium and the potassium chlorides. 
Magnesium Phosphate, like lime phosphate, is also obtained 
from food, and found in all the tissues and fluids of the body; a large NUTRITION. 
31 
quantity existing in the muscles, and much more, comparatively, 
in the brain. 
The Alkaline Salts, such as carbonate of soda and potassa, 
are essential to nutrition; yet, unlike mineral salts, they are not 
usually introduced in their own form, but rather with fruits and 
vegetables containing salts of soda and potassa, combined with 
various organic acids, such as citrates, malates, and tartrates, which 
are decomposed and become alkaline to animal secreted juices and 
fluids of the body, and may be increased by an exclusively vege- 
table, or lessened by an exclusively animal, diet. Muscular fibre 
and animal tissue contain phosphates, while vegetable matter 
abounds in said organic acids, the latter, by decomposition in the 
system, producing carbonates of the same base. If the food be 
both animal and vegetable, the salts are then found to be in proper 
proportion. As already stated, alkaline salts are derived from 
food, and excreted with perspiration, mucus, and urine. An ani- 
mal diet increases the quantity of tissue-acid (a form of lactic 
acid) in the system, and consequently more acid (though changed) 
is then found in the excretions. 
Sodium Chloride (table salt) is, next to lime phosphate, the 
most abundant of all mineral constituents in animal tissues and 
fluids. It has the property of reg- 
ulating the phenomena of endos- 
mosis and exosmosis, or the transu- 
dation of nutritive fluids through 
organic membranes. Salt excites 
the digestive fluids. Moderately 
used, it is absorbed in the aliment- 
ary canal, passes into the blood, 
then into the tissues, returns to 
the blood, and is finally discharged with the urine, mucus, and cu- 
taneous perspiration. Of the sodium chloride in the adult system 
more than ten per cent passes off daily, amounting to about fifteen 
grammes, or a little less than four drachms, of which about thir- 
teen grammes pass off with the urine and two with mucus and per- 
spiration. Sodium chloride is very important in nutrition. This, 
even the w-ise farmer knows, as is shown by his liberal supply of 
common salt to cattle to improve their condition. It furnishes the 
principal chemical material for the production of the hydrochloric 
acid of the gastric juice. 
Fig. 2. 
Crystallized Sodium Chloride. 32 
NUTRITION. 
Milk.—Nature provides the only perfect combination of food 
elements, in the form of mother’s milk, to sustain and nourish the 
infant. Milk contains all the important groups of nutritive sub- 
stances, consisting of albuminous matter, casein, sugar, and inor- 
ganic salts, especially a large quantity of lime phosphate. The fat 
globules suspended in milk (Fig. 1) give it an opaque white color. 
As the casein and albumen are associated together, milk does not 
solidify by boiling, but is covered by coagulated albumen, the 
casein remaining liquid. Any dilute acid precipitates the casein 
and curdles the milk. A moderately warm atmosphere transforms 
the sugar in milk into lactic acid, or atmospheric electricity may 
cause a similar change. 
Bread.— Bread is the most nutritious of all combinations of 
vegetable matter. It is deficient in fat; hence, butter, fat, or some 
other form of oleaginous food is usually eaten with it. The flour 
of cereal grains, of which bread is made, contains starch, albumin- 
ous matter, and mineral salts. Wheat is the best grain for bread, 
on account of its large proportion of albuminous (nitrogenous) 
matter. It contains also a peculiar adhesive or fibrinous substance 
called gluten. Oats, next to wheat, contains the largest proportion 
of albuminous matter. It contains also an indigestible vegetable 
substance, or cellulose; consequently, thorough boiling and strain- 
ing, to remove the cellulose, make it more digestible. Indian 
Corn is especially rich in fatty ingredients. Rice contains much 
starch, but very little albumen or fat. 
Meat.— The muscular flesh of various animals is extremely 
nutritious as food for the human body, containing in every hundred 
parts about 78 of water, 15 of albuminous matter, 5 of fat, and 2 
of mineral salts. The minerals consist of sodium and potassium 
chloride and phosphate, lime and magnesium phosphate. Meat 
loses, by any method of cooking, from 25 to 30 per cent of its weight, 
owing to the escape of water and liquefied fat. 
Eggs.—The yelk of the egg contains in every 100 parts about 
52 of water, 30 of fat, 16 of albuminous matter, and 2 of mineral 
salts; the white of the egg contains in every ICO parts about 78 of 
water, 20 of albumen, and 2 of mineral salts. The mineral matter 
consists mainly of sodium and potassium chlorides, potassium 
sulphate, lime and magnesium phosphates. 
Of vegetable foods, some are valuable to the animal system on 
account of their starchy and albuminous ingredients, others for 
their saccharine and watery juices, while the green parts are doubt- NUTRITION. 
33 
less useful because of the iron contained in their chlorophyll. 
The value to the system of any food substance depends upon 
the amount and requisite combination of the different proximate prin- 
ciples contained — but not upon any one singly, even if taken in 
large quantities. The quantity and kind of food required daily 
varies with circumstances—such as the size and weight of the body; 
development of the muscular and other systems; temperature; and 
especially the amount of physical activity. More food is required 
in cold than in warm wreather; more by a person of muscular than 
of adipose or phlegmatic constitution, and more in activity than in 
repose. Carbon and nitrogen are considered important constituents 
of efficiently nutritious food; carbon forming the most abundant 
and characteristic ingredient of all organic combinations, while 
nitrogen is the distinguishing element of albuminous substances, 
constituting one of the elements of all albuminoids, such as the 
alimentary digestive secretions. Of these two (carbon and nitro- 
gen), about seven ounces (or about 224 grammes) of carbon and 
five drachms (or about 20 grammes) of nitrogen are continually 
required to support the system of an adult. 
During sleep or fasting, some of the stored-up molecular energy 
constituting already formed tissues is used in the economy; therefore, 
this energy has to be renewed by introducing nourishment into the 
system; otherwise, the vitality required to keep up organic functions 
would soon diminish, and the organism begin to emaciate. On the 
other hand, if more energy than the system absolutely requires is 
supplied, then, from its superabundance the organism is in some 
way or other thrown out of order. This happens wdien food is in- 
troduced with which either certain organs or the entire system is 
already saturated, for then the functions of the organs become 
deranged. 
The Amyloid. Compounds, such as glucose, glycogen, and 
dextrose, differ from protein compounds by containing neither 
nitrogen nor sulphur. CHAPTER II. 
ACTIVE PRINCIPLES IN LIQUIDS AND SOLIDS. 
The most active principles in the liquids and solids of the body- 
are the albuminoids, viz.: 
Fluids — Casein, ptyalin, pepsin, pancreatin, mucosin, and 
myosin. 
Solids—Collagen, chondrin, elasticin, and keratin. 
In Coloring Matter—Haemoglobin, melanin, bilirubin, bili- 
verdin, urochrom, and chlorophyll. 
Casein is the principal nutritive substance in milk. When solid- 
ified it forms cheese. Boiling does not coagulate it, but dilute 
acids and magnesium sulphate do. Casein, when subjected to a 
highly acid condition of the gastric juice, or at a high tempera- 
ture, coagulates. Milk, therefore, is not a proper article of diet 
when the stomach is abnormally acid. 
Ptyalin is the principal active agent in saliva. It augments 
the stimulation for increased secretion of saliva, which converts 
hydrated or moist boiled starch into glucose. The daily secretion 
of saliva in an adult is about 40 fluid ounces. 
Pepsin is the principal constituent of the gastric juice. It is 
secreted by the glandular follicles of the stomach to aid digestion. 
About fifteen parts of pepsin are found in one thousand parts of 
the juice. During digestion the pepsin converts the albuminous 
(nitrogenous) matter into peptones. The daily secretion of gastric 
juice by an adult is about six pints. ( Vide Digestion.) 
Pancreatin is the characteristic active ingredient of the pan- 
creatic juice. Its proportion is about ninety parts of pancreatin 
in every thousand parts of juice. The amount of the daily secre- 
tion of juice by an adult is about ten ounces. The physiological 
property of the alkaline pancreatic juice is to emulsify and partly 
saponify fatty matter and to neutralize the fatty or oily acids. The 
juice has also the power of converting starch into glucose, even 
more so than saliva. 
Mucosin, or Mucin, is a viscid, thick, glutinous constituent 
of mucus. It gives to mucus its glutinous consistency. There are 35 
ACTIVE PRINCIPLES IN LIQUIDS AND SOLIDS. 
a variety of secretions called mucus that have the peculiar phys- 
ical character of viscidity, keeping the membranes moist, thus en- 
abling them the better to perform their functions. 
Myosin is the contractile substance of muscular fibres. After 
death it coagulates; then the muscle loses its contractility and as- 
sumes a cadaverous rigidity. Cold retards itg coagulation. It is 
completely soluble in dilute acids and alkalies; on this account 
abnormally increased acidity or alkalinity of the system produces 
muscular weakness. 
Collagen forms the homogeneous interstitial mass of bones, 
periosteum, tendons, ligaments, fasciae, and connective tissue. 
When boiled it produces gelatine or glue. One part of collagen is 
precipitated in 5000 parts of water if tannic acid be mixed with it. 
Tannic acid hardens the collagen of the fibrous tissues in hides. 
They then become less permeable to water and almost incapable 
of putrefaction—leather. 
Chondrin is the organic basis of cartilage. It is jelly-like in 
•consistency. 
Elasticin is the homogeneous material of tissues. It is found, 
for example, in the middle coat of the larger arteries, elastic liga- 
ments of the spinal column, ligamentum nuchae, and all other yel- 
low elastic structures. 
Keratin is the resisting and indestructible substance of the 
Iiair, nails, epidermic scales, feathers, and all horny tissues. Sul- 
phur is one of its constituents. 
The Coloring Matters are all albuminoid compounds. The 
red coloring matter (haemoglobin) is the most abundant, being the 
agent by which oxygen is absorbed in the lungs, taken up by the 
blood, and distributed in the organism. Animal coloring matters 
are found in the blood, in the blackish-brown solid tissues, bile, 
and urine. 
Haemoglobin is the coloring matter of the red blood-corpus- 
cles, constituting about 90 per cent of their bulk. It is a powerful 
absorbent of oxygen, retaining it in loose combination; it contains 
about 0.42 per cent of iron, derived from vegetable and animal 
foods. 
Melanin is the dark coloring matter of tissues, found in the 
choroid coat of the eyeball, in the rete Malpighii of the skin, in the 
hair, and is more abundant in black and brown colored people, 
producing different grades of color according to its proportion in 
the tissue. 
Bilirubin is the reddish-yellow or orange coloring matter of 36 
ACTIVE PRINCIPLES IN LIQUIDS AND SOLIDS. 
the bile. It is formed in the substance of the liver from the haemo- 
globin of the red blood-corpuscles dissolved in the spleen. (Vide 
Spleen.) 
Biliverdin is formed partly by transformation from bilirubin 
and partly from chlorophyll. It is the green coloring matter of bile. 
When animals feed on green vegetables the coloring matter of 
their bile is extremely green. 
Urochrom is the coloring matter of urine. Fresh, normal 
urine has a light-yellow or amber color. 
Chlorophyll is an alkaloid constituting the green coloring 
matter of plants. It is produced in the vegetable cells. If defi- 
cient in plants they grow up blanched, or in a chlorotic condition. 
Its essential substance seems to be iron. The entire process of veg- 
etation, production and accumulation of organic material in the 
form of starch, sugar, cellulose, woody fibre, and the substance of 
vegetable tissues, is inseparably dependent on the presence of 
chlorophyll. Its function is not that of a simple chemical reagent, 
but of an active constituent, its presence being just as essential as 
the presence of air, sunlight, warmth, and moisture to the living 
vegetable organism. 
Urea is a colorless substance, with a neutral reaction, soluble 
in water, and crystallizing in four-sided prisms. It forms the prin- 
cipal solid constituent of urine. Formerly, it was regarded as an 
organic base or albuminoid of animal origin; though of late it is 
placed amongst the amides, and termed carbonic oxide, carbonyl, 
or amide of carbonic acid. It is found not only in urine, but in 
such excreted fluids as perspiration and tears. That urea, as such, 
exists normally in the blood and tissues, must remain a matter of 
doubt. It is an established fact that some persons, when eating 
meat in sufficient quantities, have excreted as much as 1540 grains 
of urea in twenty-four hours, yet apparently enjoyed perfect health. 
Now, if, within a period of twenty-four hours, this amount of urea 
existed already formed in the blood and tissues, it would poison 
the person and produce unconsciousness. Hence, we are con- 
strained to conclude that urea is completely formed only by the 
organs of exit. The blood, lymph, and tissues contain urea ele- 
ments. They are secreted and urea completely formed by the cells 
of the uriniferous tubules of the kidneys, and by the sudoriparous 
cells of the skin, and are by these organs (kidneys and skin) ex- 
creted. When some of the excretory channels are in a defective 
condition, the ready formed urea is easily reabsorbed by the ACTIVE PRINCIPLES IN LIQUIDS AND SOLIDS. 
37 
capillary veins and capillary lymphatics, and it may then be 
carried to any part of the body, and be found in the blood, lymph, 
and tissues. Urea constitutes about 26 parts in each one thousand 
parts of urine. About sixteen parts of urea may be found in each 
hundred thousand parts of blood. About 33 grammes (nearly 500 
grains) per day are excreted by an adult. A larger quantity is 
produced during waking than sleeping hours (accounted for prob- 
ably by the action of both the nutritive and digestive functions), 
and more is produced in the later than in the earlier part of the 
day—mostly discharged from 6 to 10 p. m. The quantity excreted 
varies in proportion to the amount of albuminous and starchy 
matter in the food. As urea is now placed amongst the amides, starch 
must, consequently, contribute some elements to its formation. 
Urea is increased by a diet of animal food, also by unusual mus- 
cular exertion, diminished by vegetable food, and reduced to its 
minimum by a diet of non-nitrogenous matter, such as sugar and 
fat. It is not dependent solely on food, however, but is partly de- 
rived from the metamorphosis of the tissues of the body, as 
some urea is discharged even when no food is taken. ( Vide Urine.) 
Uric Acid is next in importance to urea, and is found in urine. 
It is a colorless, crystallizable substance, soluble in either cold or 
hot water, and, like urea, formed in the organs of exit, either from 
substances not properly formed into urea, or from elements arising 
from the metamorphosis of albuminous and amyloid substances 
of the food and of the ready formed tissues of the body. Its 
principal bases are acid urates of sodium and potassium, the so- 
dium urate predominating. Animals nourished principally by 
vegetable food excrete more uric acid than urea, while those sub- 
sisting mainly on albuminous (nitrogenous) diet excrete less uric 
acid but more urea. The quantity excreted by a human adult is 
about from six to nine grains in twenty-four hours, or in the pro- 
portion of one of uric acid to forty-five of urea. Urinary gravel 
and calculi are often composed of uric acid. 
Urine, on account of the great quantity of salts contained there- 
in, is not absorbed from the bladder, as strong salt liquids are not 
osmotic. Bathing in fresh water relieves thirst, but bathing in 
strong salt water does not. CHAPTER III. 
THE MUCOUS MEMBRANE AND EPITHELIUM. 
It may possibly be considered a new or unusual thing to de- 
vote a chapter to a consideration of the construction and function 
of the mucous membrane and epithelium; but pro novo homine med- 
ico, it will doubtless be well to call attention to the fact that, phy- 
siologically, there is no organ of such fundamental, vital impor- 
tance to the nourishment of the human body as a healthy mucous 
membrane; for there are very few pathological conditions in which 
it is not primarily, or becomes secondarily, involved; and, when 
defective, it exerts an important influence in retarding the proper 
nourishment of certain parts, or of the entire system. If more 
attention were paid to the condition of the mucous membrane, 
especially of the lower portion of the oesophagus, and of the stom- 
ach, and to their abnormal acidities, many cases of starvation 
would be prevented, and death certificates signed “phthisis,” or 
“consumption,” would be considerably reduced in number. That 
abnormal acidity is always the cause of digestive disturbance must 
not be inferred, as many vital pathological conditions of near or 
remote parts may also produce digestive derangement; but reference 
is made to abnormal acidity simply to indicate the necessity of be- 
ginning observations at the foundation—the mucous membrane. 
In nine cases out of ten the trouble will be found there; for the 
mucous membrane of the lower portion of the oesophagus, from 
the diaphragmatic oesophageal opening to the cardiac orifice, is 
the first severely affected by the ingesta, be that solid or fluid, hot 
or cold, exciting, depressing, irritating, or inflaming, distending 
or contracting, wholesome or harmful. That these influences may 
easily produce an abnormal secretion of acid for the gastric juice 
must be seen at a glance. Again, there can be no doubt that 
ptomaines (alkaloids derived from dead animal tissues or decompos- 
ing proteids) exert their influence to a much wider extent in patho- 
logical conditions than is at present suspected. In no tissue of the 
body are ptomaines developed so favorably as in the mucous mem- 
brane, as it is very delicate, easily degenerates (though it rapidly re- 39 
THE MUCOUS MEMBRANE AND EPITHELIUM. 
pairs, generally), and is in direct contact with the atmosphere and 
its animalculae, which find in the ptomaine, or defective or dead 
parts of the mucous membrane, a most favorable soil to multiply, 
and especially to develop saprophytes or pathogenytes. When a pto- 
maine is once developed, its animalculae product is easily absorbed 
and carried by the lymph and blood to a distant organ, which then 
suffers. The lung is continually active in extending and contract- 
ing, and is very delicate in structure, which no doubt accounts for 
its being affected in by far the greater number of all diseases; and 
it is not difficult to comprehend that the primary cause of pulmon- 
ary tuberculosis is found in a mucous membrane, be that the 
Schneiderian, respiratory, genito-urinary, or alimentary—especially 
the latter, from whence the lungs may become subsequently affected. 
Mucous Membrane.—In structure the mucous membranes 
are soft, spongy, and velvety; well supplied with blood-vessels, lym- 
phatics, nerves, follicles, and minute glands imbedded in their 
fibrous and submucous tissues. The outer layer of the mucous 
membrane has a free surface formed of epithelial cells, resting on 
a thin, transparent, homogeneous layer, termed basement mem- 
brane, beneath which is a stratum, or layer, of fibrous tissue adher- 
ing to the submucous structure, and Avell interwoven with vascular 
tissue (Figs. 8 and 13). They include the linings of all internal 
passages that communicate externally with the skin, such as at the 
nose, eyes, ears, alimentary, respiratory, and genito-urinary; but 
never form completely closed sacs as do the serous membranes. 
The mucous membranes are also very sensitive and irritable. Their 
cells secrete mucus, consisting of mucosin (mucin), water, and 
alkaline salts, such as potassium, soda, and lime phosphates, 
keeping the membrane moist so as to better perform its functions. 
Mucus is peculiarly viscid, translucent, thickly glutinous, differing 
somewhat in consistency in different parts of the mucous mem- 
brane, the surface of which it covers. Normally, it is of thicker 
consistency than the fluid of serous membranes. According to lo- 
cation, the surface of the mucous membrane is either in the form 
of villi, projecting papillae, or depressions; the latter being in the 
form of ducts of either follicles or glands (Figs. 8 and 13). In 
the stomach, uterus, and bladder the submucous tissue forms a 
distensible layer, so as to permit of considerable extension without 
injury. In contraction of these organs the mucous membrane is 
thrown into folds. 
The mucous membrane of the alimentary canal commences at 40 
THE MUCOUS MEMBRANE AND EPITHELIUM. 
the lips and ends at the anus; its glands and follicles furnishing the 
true digestive secretions for the reduction of food, while the villi 
absorb the nutrient materials thus reduced to a liquid. The sali- 
vary glands furnish saliva; the lower portion of the oesophagus the 
acid, and the gastric follicles the pepsin of the gastric juice; the 
glands and follicles of the small intestine the intestinal secretions; 
while the membrane of the large intestine also absorbs fluid sub- 
stances, and constitutes an outlet, that emits not only the indigest- 
ible residue of food, but its numerous minute excretory follicles, 
lined with epithelial cells, separate products from the blood that 
must be excreted to prevent disease. ( Vide chapters on Digestion, 
Secretion and Excretion.) 
The mucous membrane of the nostrils extends through the lach- 
rymal duct, forming a junction with that of the eye. In the vault 
of the pharynx it continues the lining of the Eustachian tube and 
wall of the cavity of the tympanum (middle ear); while in the 
pharynx it continues as the pharyngeal mucous membrane to the 
alimentary tract. 
Through the alimentary and respiratory mucous membrane the 
elementary nutritious materials are absorbed for the body. The 
cells of the secreting follicles and glands of the alimentary mucous 
membrane produce the various digestive fluids; and, that the nu- 
tritive materials may be of benefit to the system, they are absorbed 
by absorbent vessels in the membrane and conveyed into the blood 
circulation. 
The respiratory mucous membrane lines the larynx and trachea, 
and extends to the bronchial tubules. Each tubule is about l-60th 
of an inch in diameter. From this situation on, the membrane is 
very delicate, and continues to the pulmonary alveoli (air-cells), 
and serves for the absorption of oxygen and the exhalation of car- 
bonic acid gas, as well as for keeping the air passages moist with a 
layer of mucus, protecting the membrane from irritation. If conges- 
tion exists, as in a certain stage of bronchitis, this mucus secretion 
is at first diminished and afterward increased. It is also increased 
by administering either apomorphine, ipecac, emetine, or pilocar- 
pine, while it is diminished by belladonna (atropia) and opium 
(morphia). In expelling copious secretions from the bronchial 
tubes, expectorants may operate in one of two ways—either by 
local stimuli to the bronchial or gastro-oesophageal mucous mem- 
brane, forwarding an increased afferent stimulus to the medulla 
oblongata, which sends a reflex impulse correspondingly through THE MUCOUS MEMBRANE AND EPITHELIUM. 
41 
the phrenic and intercostal nerves to the respiratory muscles, effect- 
ing forcible expectoration (mechanical), such as results from ad- 
ministering ipecacuanha or lobelia: or by means which change the 
secretion at the same time, as apomorphine, pilocarpine, or emet- 
ine. This change of secretion is materially assisted by warm drinks 
or moist inhalations. ( Vide chapter on Respiration.) 
The genito-urinary mucous membrane begins at the genito-urin- 
ary orifices, and lines the urethra, bladder, ureters, pelvis of the 
kidneys, vagina, uterus, and Fallopian tubes. 
The moment any mucous membrane becomes much congested 
and inflamed, the intercellular epithelial spaces become blocked 
and the mucus-secreting cells beneath restrained in activity, while 
the epithelial cells lining the membrane and ducts are much more 
active, but deprived of their protector (the mucus); consequently, 
their secretion becomes abnormally increased and acid. The epi- 
thelial cells and glands of the lower portion of the oesophagus are 
very numerous, and placed in ring-like arrangements above and 
around the inner surface of the cardiac orifice; which, being habit- 
ually closed, retains the food more or less in that portion; so that 
when food is introduced, especially of a solid, irritating nature, or 
difficult of digestion, these cells and glands become very active; the 
congestion of the membrane is abnormally severe, and the acid se- 
cretion is increased. Every one must have experienced, after the 
introduction of such food, the excessive sourness of the digestive 
process. This process of vital tissue acid secretion (a form of lactic 
acid, and the only acid normally formed primarily,) also applies 
to the stomach, where the lactic acid becomes generally changed into 
hydrochloric acid. The acid secretion of the lower portion of the 
oesophagus, and of the stomach, though in the latter in a less degree, 
takes place normally when food of more or less difficult digestion 
is taken; but when it occurs in the small intestine it is entirely ab- 
normal, and gives rise to a pathological condition. 
Next in order, as a suffering organ, is the stomach. When its 
mucous membrane is continually irritated, the mucus secretion 
becomes diminished; consequently, its natural protector, the alka- 
line mucus, is wanting, and the membrane softens. The acid secret- 
ed has then full play, not only on the ingesta, but also on the cells 
of the membrane that produced the acid. Now, any alcoholic 
drink, sugar, or food prepared from pure starch, which becomes 
changed during digestion into sugar, or any other solvent or irri- 
tant to said membrane, increases the acid secretion and softening; 42 
THE MUCOUS MEMBRANE AND EPITHELIUM. 
and, if continued, there can be no other termination than indiges- 
tion, diminished absorption, and starvation of the body. 
That the stomach normally secretes very little or no acid, was ob- 
served in 1834 by Eberle—“that by maceration of gastric mucous 
membrane in acidulated liquid, an artificial gastric juice is ob- 
tained.” This shows that the pepsin is in the gastric membrane 
(some of the pepsin being retained, possibly, in the gastric follicles), 
but the acid has to be added. Physiologically, the function of the 
lower portion of the oesophagus is important, as it secretes nor- 
mally the acid for the gastric juice; but when the acid secretion is 
abnormally increased, it exerts a powerful influence in reference to 
indigestion, diarrhoea, anaemia, inanition, and consumption. (Vide 
chapters on Secretion, and Digestion.) 
Endothelium consists of one or more thin layers of cells, des- 
titute of blood-vessels and nerves. It forms the lining of internal 
dosed cavities. Its free surface (examples of which are found in 
the membrane of the cavities of the brain, of the central canal 
of the spinal cord, of the interior of lymphatics, blood-vessels, 
serous, cardiac and synovial cavities, and the membranous labyrinth 
of the internal ear) is not exposed directly to the air. The endo- 
thelium of these structures consists of flattened, irregular squamous 
cells, adjusted to each other closely, and so presenting a smooth 
surface. 
Epithelium consists of one or more thin layers of cells cement- 
ed together by a clear albuminous intercellular substance. It 
covers the entire free surface of the body and internal open passages, 
and such organs as the liver, kidneys, lips, etc. A free surface is a 
structure not blended with, nor attached to, adjacent structures, but 
is free, or separable from them without the necessity of dissection. 
Epithelium covers not only the entire external surface of the 
body, as the epidermis of the skin and its appendages (the nails 
and hair); but also the lips, membrane of the nose, and mouth; 
and continues over the entire mucous membranes of the internal 
open passages, such as the respiratory, alimentary, genito-urinary, 
the lining membranes of ducts of secreting follicles and glands, the 
membrane of the anus, external auditory canal, and of the tym- 
panum, or middle ear. 
Epithelial Cells are of various shapes, and may be classified 
into five varieties—ciliated, columnar, squamous, glandular, and 
transitional. Each class of cells has a special function to perform 
in the economy, though all serve one purpose in common; viz., to THE MUCOUS MEMBRANE AND EPITHELIUM. 
43 
protect the surface of the respective membranes which they cover. 
This function is assisted by secreting cells lying beneath and partly 
between the epithelial cells, and secretes more or less moisture 
over the epithelium. Thus, the cells underneath seem to appreciate 
the kindness of their protectors, so that when the epithelium be- 
comes irritated or inflamed, especially that of the mucous mem- 
brane, the mucus-secreting cells immediately increase their activity 
by furnishing an increase of mucus, which passes by exosmosis 
through the albuminous intercellular epithelial substance to the 
surface of the membrane for its protection. This view seems more 
tenable than that which holds the mucus secretion to be a gradual 
dissolution of the outermost epithelial cells. The principal con- 
stituent of mucus is mucosin, one-eighth of which is nitrogen. By 
the mucosin, nitrogen is considerably eliminated from the blood, 
which may explain the anaemic condition of persons having a de- 
fective mucous membrane or insufficiency of mucus secretion, nitro- 
gen being, in this case, insufficiently eliminated. 
The Ciliated variety (A, Fig. 3) consists of columnar cells (1) 
internally pointed, each cell containing a nucleus (3). On the sur- 
Fig. 3. 
A—1, Ciliated columnar epithelial cells. 2, Cilia. 3, Nucleus, 
4, Young cells. 5, Elastic basement membranous and fibrous tissue, 
B—Columnar epithelial cells. 1, Club shaped. 2, Its nucleus. 
face of the mucous membrane these cells have projecting cilia (2) 
of about l-3000th of an inch in length, which vibrate about 700 
times per minute in the fluid which moistens the surface of the 
membrane, thereby propelling the mucus or other minute particles 
towards the orifice of the cavity or tube of the membrane which 
they line. These cells are found on the mucous membrane lining 
the nose (except the olfactory portion), lachrymal ducts, Eusta- 
chian tubes, tympanum, larynx, pharynx (excepting the vocal 
chords), trachea, bronchial tubes, uterus, Fallopian tubes, and vasa 44 
THE MUCOUS MEMBRANE AND EPITHELIUM. 
efferentia. Each cell may have from ten to thirty cilia, placed at 
regular distances. 
The Columnar variety (B, Fig. 3) consists of cylindrical col- 
umns or club-shaped nucleated cells (1), about l-500th of an inch 
in length, placed side by side perpendicularly. They are found on 
the mucous membrane lining the alimentary canal from the dia- 
phragmatic oesophageal opening to the anus, secreting follicles, and 
ducts of secreting glands, gall-bladder, and the urethra. Sometimes, 
near the surface of the mucous membrane, the upper end of these 
cells are distended, forming the Goblet Cells (A, A, Fig. 4). 
The Squamous variety of cells (1, Fig. 4) is a flat thin plate with 
an oval nucleus, differing in shape and size in different localities. 
These cells are found on the epidermis, hair, nails, internal lining 
of the arteries, veins, capillaries, lymphatic vessels, acini of the 
lungs, aqueous chambers of the eye, uriniferous tubules of the kid- 
neys, and on the serous membranes (pleura, pericardium, and peri- 
toneum). The Tessellated epithelium consists of nucleated flat- 
Fig. 4. 
C, Squamous and Tessellated epithelial cells. 1, Squamous. 2, 
Tessellated. 
D, Columnar and goblet epithelial cells. A, A, Goblet cells are 
simply distended Columnar cells (B). 
tened scales from 1-lOOOth to l-600th of an inch in diameter (2, Fig. 
4). They are like the squamous, but considerably larger, and 
scattered among them. They are found in nearly all localities 
mentioned with the squamous; and also on the mucous lining of 
the mouth, pharynx, oesophagus, vestibular entrance to the nose, 
conjunctiva, entrances to the urethra and vagina, and the greater 
portion of the epidermis. 
The Glandular epithelial layer (E, Fig. 5) consists of nucle- 
ated cells. They are found in the acini of the various secreting 
glands, and in the convoluted uriniferous tubes of the kidneys. 
These cells separate from the blood the materials out of which THE MUCOUS MEMBRANE AND EPITHELIUM. 
45 
they produce or secrete the different fluids, follicular and gland- 
ular juices. 
The Transitional epithelial cells (H, Fig. 5) occur in many 
different shapes, sizes, and localities, all having a flattened surface, 
and some a rounded extremity. These cells are found on the mu- 
cous membrane of the bladder, pelvis of the kidney, and ureter; 
they are often intermixed with the columnar epithelial cells, as in 
the larynx and pharynx. 
All varieties of epithelial cells are, as a rule, arranged in layers, 
or strata. The cells next to the surface have a tendency to be 
shed, and their place is then taken by the cells of the deeper lay- 
ers, which become modified in form as they approach the surface. 
The cells of glands, also, are constantly cast off; yet each gland 
maintains its form and proper composition, and for every cell 
Fig. 5. 
E, Glandular epithelial cells. H, Transitional epithelial cells 
thrown off a new one is produced. The epidermis furnishes a good 
example, the surface cells thereof be constantly thrown off by those 
newly formed beneath. ( Vide chapters on Secretion, Absorption, 
Digestion, and the Skin.) CHAPTER IV. 
DIGESTION. 
The Digestive Organs include the mouth, stomach, and small 
intestines; the Digestive Apparatus, however, may be said to 
include the mouth, oesophagus, stomach, small intestines, liver, and 
pancreas. Each one of these organs secretes a particular digestive 
juice differing from the others (the oesophagus secretes a liquid 
acid), each secretion performing its particular work in the process 
of digestion. 
Digestion is the process of reducing the materials of the food 
to a semi-fluid form, fitting it for absorption into the circulation 
and for assimilation. It is partly a mechanical process (mastica- 
tion), and partly a chemical process (solution and transformation 
by the juices). Food is composed of organic and inorganic sub- 
stances, and to be of use in the economy must be assimilated. 
Animal life, unlike vegetable, requires material that has already 
been organized, and which must be digested before it can be taken 
up by the absorbent vessels. Some of the digested, or liquefied, 
food is then carried into the circulation; the remainder is dis- 
charged as feces. 
The Alimentary Canal is the passage through the body from 
the mouth to the anus, and is divided into several compartments 
by narrow constrictions (guards), through which the compartments 
communicate with each other. The mouth is guarded by the valve 
of the isthmus of the fauces; the oesophagus is guarded at the car- 
diac and the stomach at the pyloric orifice. Then follows the 
small intestine, about twenty-five feet in length in the adult. An- 
atomically and physiologically, the small intestine is subdivided 
into three parts; viz., the duodenum, jejunum, and ileum. In the 
duodenum are the orifices of the biliary and pancreatic ducts; at 
the end of the ileum is the guard termed ileo-caecal valve; then fol- 
lows the large intestine, which is guarded by the sigmoid flexure; 
then passes on and terminates at the anus, guarded by a double 
sphincter muscle. The ileo-ca3cal valve allows fecal matter, or that 
which has not been appropriated by the system, to pass from the DIGESTION. 
47 
small into the large intestine; so that in the normal state no regur- 
gitation of the ingesta from the large to the small intestine occurs. 
The large intestine (colon) is about five feet in length in the adult. 
Its contents differ much from those of the small intestine, especially 
in being more solid. In passing towards the exit the contents become 
more solid, in consequence of the absorption of the fluid by the 
mucous membrane. The vermiform appendix (8, Fig. 6), below the 
ileo-cseeal valve, may possibly serve as a large secreting follicle to 
lubricate the acute curve at the 
valve with a large quantity of an 
alkaline secretion. When the al- 
kaline secretion of the ileum is 
deficient and acidity occurs—caus- 
ed especially by irritating food, 
and certain kinds of fruit—great 
pain results; but the alkaline se- 
cretion of this appendix may sub- 
due the irritation and pain, by neu- 
tralizing the acidity. 
The Stomach (3, Fig. 6) consists 
of four different tissue layers— mu- 
cous, submucous (fibrous), muscu- 
lar, and serous (Fig. 13). The serous 
is the most external, the mucous the 
most internal, the other two being 
situated between them. The wall 
of the stomach averages about a 
line, or l-12th of an inch, in thick- 
ness. Its muscular layer is about 
one-half of the thickness of the wall, 
and its fibres are arranged in three 
sets—the longitudinal, externally; 
the oblique, internally; and the cir- 
cular, between. When the stomach 
is distended to 12 or 15 inches later- 
ally and about five antero-posteri- 
orly, it has a capacity of about four 
or five pints. The stomach is sup- 
plied with blood-vessels, lymphat- 
ics, nerves, and secreting follicles; 
the latter consisting of tubes set 
Fig. 6. 
Diagram of Alimentary Canal 
from (Esophagus to Anus. 
1, (Esophagus. 2, Diaphragm. 
3, Stomach. 4, Duodenum. 5, 
Small intestine. 6, Ileo-caecal valve. 
7, Caecum. 8, Vermiform appen- 
dix. 9, Ascending colon. 10, Trans- 
verse colon. 11, Descending colon. 
12, Sigmoid flexure. 13, Rectum. 
14, Diaphragm attached to lower 
part of chest-wall. 15, Spleen. 48 
DIGESTION. 
closely together transversely in the mucous membrane. The fol- 
licles (A, A, Fig. 13) are from about l-60th to l-30th of an inch 
in length, and terminate in blind extremities in the wall of the 
stomach. The mouths of the ducts of these follicles are from 
l-500th to l-300th of an inch in diameter, and open on the sur- 
face of the mucous membrane, in the interspaces between its 
projecting folds. The wall of each follicle is provided with co- 
lumnar epithelial secreting cells (D), ovoid in shape, each about 
l-1200th of an inch in diameter. The surface of the mucous 
membrane is covered with a layer of transparent columnar epithelial 
cells (E), which secrete a thick, tenacious, alkaline mucus, for the 
protection of the mucous membrane of the stomach. The cells secret- 
ing the mucus of the membrane are active even during fasting; 
while the cells of the gastric follicles secreting the pepsin are active 
only when food or a foreign substance enters the stomach. The stim- 
ulus for the secretion of pepsin and for the peristaltic activity of the 
stomach is due to the sensation of touch caused by the presence of 
the ingesta. As all external sensations (as will be noticed in 
the chapter on the Senses) require for their activity a combination 
of three distinct but associated organs—viz., the peripheral organ 
(or cells) of sensation, a nerve fibre or fibres, and a nervous cen- 
tre (or cells)—so it is in regard to the sensation of touch in the 
stomach. The presence of ingesta causes the sensation in the stomach, 
inducing a powerful stimulus, which is carried through afferent 
fibres of the pneumogastric nerve to the medulla oblongata, which 
reflects the stimulus by sending a vaso-motor impulse through the 
efferent fibres of the splanchnic nerve, passing through the gastric 
plexus and entering the wall of the stomach. The efferent (vaso- 
motor) fibres induce dilatation of the capillary vessels, so that the 
secreting cells of the gastric follicles in the wall of the stomach 
receive abundant material for the secretion of the pepsin of the gas- 
tric juice. The acid of the gastric juice is not secreted by the cells 
of the gastric follicles. (Vide Gastric Juice.) The efferent im- 
pulse to the cells of the muscular fibres of the stomach causes them 
to become very active, at the same time inducing the peristaltic 
action—effected by the peculiar arrangement of the longitudinal, 
oblique, and circular layers of the muscular fibres. The peristal- 
tic action of the stomach is essential to digestion, bringing all the 
food in contact with the gastric juice, causing intimate mixture 
and solution of the food. 
Digestion of Food is effected by mastication and solution; DIGESTION. 
49 
the latter being brought about partly by the saliva and partly by 
the digestive juices in the alimentary canal. Mastication by the 
mouth is essential before the food is properly tit for the dissolving 
changes during the digestive process, not only on account of the 
physically fine reduction and solution of the materials, but also 
on account of the action of the saliva, termed insalivation, which 
is of a chemical nature, acting on the insoluble starch of food and 
converting it into soluble glucose (grape sugar). The active prin- 
ciple effecting this chemical change is the ptyalin of the saliva. 
Raw starch is indigestible by the human stomach, and often passes 
unchanged from the bowels; but when thoroughly hydrated it is 
easily acted on, and transformed by the saliva and pancreatic juice 
into glucose. It is for this reason, also, that starchy vegetables 
require thorough solution by cooking to render them digestible. 
Sago, tapioca, and arrow-root are composed of starch almost entirely; 
wheat contains 70 per cent, and rice 90. Peas, beans, chestnuts, 
acorns, rye, oats, and potatoes also contain considerable starch. 
Normal gastric juice does not change starch into glucose; neither 
can the saliva accomplish this change in the stomach, on account 
of the acid of the juice; but the action of moisture, heat, and acid 
dissolves the starch and separates the dextrin, which is isomeric 
with glucose, and is like gum arabic, sticky and adhesive. During 
digestion the dextrin is dissolved into dextrose, which is similar to 
glucose in that it polarizes light to the right, but it has not the sig- 
nificance of glucose in digestion nor in nutritive properties. The 
movements of the stomach during digestion are like the process of 
kneading. The food is moved toward the left of the stomach into its 
great pouch, then downward, and along its greater curvature to the 
pyloric portion, and finally carried to and fro to every part of the 
organ and mixed with the gastric juice. The product of the solu- 
tion and disintegration of the food substances in the stomach is 
termed chyme. The normal secretion of the mucous membrane 
of the empty stomach is alkaline. (Vide chapter on Mucous Mem- 
brane.) The stimulus of food promotes the activity of the cells 
of the follicles and the consequent secretion of the normal pepsin 
of the digestive gastric juice. ( Vide Fig. 13.) If the action be too 
prolonged, however, the cells become exhausted, and any excess of 
food must remain undigested and pass into the intestine in a crude 
state, causing irritation and acidity until expelled. In disease, the 
normal stimulus by the food and the normal functions of the se- 
creting cells are more or less impaired, consequently there is no 50 
DIGESTION. 
desire for food. If food is taken then, it does not stimulate the cells 
to the secretion of gastric juice, but remains undigested, adding 
irritation to the other morbid conditions. The secretion of gastric 
juice is influenced by, though not dependent on, nervous agency. 
Strong mental disturbance, unusual fatigue, also febrile conditions, 
interfere with the digestive process—possibly by weakening the 
stimulation on the gastric membrane and the reflex action of the 
nervous centre cells; hence, there are no, or only impaired, vaso- 
motor impulses. Gastric digestion consists in a dissolution of the 
food by the gastric juice, the action of this juice being assisted by 
the peristaltic movements of the stomach. A temperature of from 
98.5° to 100° F. is required for the perfect action of the juice; hence, 
cold and iced substances taken to excess depress the temperature of 
the stomach and are injurious. Moderate exercise before and rest 
after a meal facilitates digestion. As soon as the gastric contents 
pass into the duodenum, the action of the pepsin and the acidity of 
the chyme suddenly cease on account of the action of the bile pre- 
cipitating the pepsin, and the alkaline pancreatic and intestinal 
juices neutralizing the acid. The bile and the alkaline secretions 
then further act upon, dissolve, and disintegrate the peptones and 
other ingredients of the chyme, transforming it into chyle. In 
that manner the peptones become real albuminose, fibrinose, and 
globulose, which, when absorbed by the lacteals, become albumen, 
fibrin, and other essential material of the circulating blood. It is 
by the digestive processes that the food substances are dissolved and 
the chemical atoms and molecules liberated and enabled to form 
new compounds in the economy. The nutritive substances enter 
the blood-circulation, and the cells of the secreting follicles and 
glands secrete from the blood the many different active principles: 
the albuviinoids, or so-called proteids, of solids and fluids — such 
as haemoglobin, casein, ptyalin, pepsin, pancreatin, mucosin, myo- 
sin, melanin, collagen, chondrin, elasticin, and keratin. Again, the 
liberated atoms and molecules of properly digested food furnish also 
the material for the construction and formation of the many differ- 
ent tissues. These facts indicate that it is of vital importance to the 
economy that the food taken be always properly masticated and 
digested. 
Food in its passage through the alimentary canal is acted upon 
by at least five different secretions; viz., saliva, gastric juice, bile, 
pancreatic and intestinal juices, which produce successivelv not 
only simple solutions, but also more or less transformations of the DIGESTION. 
51 
food into new substances. The products are then absorbed, some 
by the capillary veins, others by the lacteals of the small intestine, 
and become mingled with the blood; the indigestible substances 
pass through the ccecal valve into the large intestine, and are finally 
expelled writh the feces. (Vide chapter on Absorbent and Lymph- 
atic System.) 
Gastric Juice.—The cells of the mucous membrane of the 
lower portion of the oesophagus and at the region of the cardiac 
orifice of the stomach secrete principally the acid, which is a result 
of the irritation of the part. This acid may be called a vital tissue 
acid. It is similar in composition to lactic acid. Through the 
•sodium chloride of food, heat, and the moisture of the stomach, this 
acid is generally changed into hydrochloric acid; but, when milk 
or starchy food only is taken, the acid remains lactic acid, instead 
of being transformed into hydrochloric. The cells in the walls of 
the follicles of the mucous membrane of the stomach secrete from 
the blood of the arterial capillaries an albuminoid (proteid) termed 
pepsin. This is the characteristic active principle of the gastric 
juice. It requires for its action, however, the presence of a free acid, 
•either hydrochloric or lactic—the pepsin in the stomach cannot act 
upon animal food without an acid reaction. An acid, therefore, is 
first secreted as soon as the food passes through the lower portion 
of the oesophagus. The acid-secreting cells are very active, so that 
when the last portion of the meal has passed into the stomach the 
lower part of the oesophagus is still in a state of irritation and in 
an acid condition. This acidity is gradually neutralized during 
digestion by the slightly alkaline saliva swallowed; consequently, 
to a person with deficient saliva or delicate mucous membrane of the 
oesophagus, expectorating the saliva soon after a meal is very in- 
jurious, as the acidity of the oesophagus is not relieved. Physio- 
logically, it would be out of question to treat such a case for 
gastric indigestion or dyspepsia, and make the stomach suffer when 
it is not at fault. Of course, the alkalinity and the acidity can only 
manifest their proper action when the oeosphageal and gastric 
secretions are in normal condition. When the normal acid of the 
gastric juice is deficient or suppressed, the administration of prop- 
erly diluted hydrochloric acid will prove beneficial. On the other 
hand, when the acid secretion is normal, or excessive, then the 
administration of an acid diminishes gastric digestion. Failure 
•of sufficient secretion of acid lies generally in an abnormal thicken- 
ing of the mucous membrane of the lower portion of the oesophagus, 52 
DIGESTION. 
lessening the irritation by the food substances on this organ. 
The eating or drinking of irritating, fermentive, or indigestible 
liquid or food generally causes increased secretion of acid. It 
would be very difficult to succeed in treatment where there is an 
impaired mucous membrane and increased acidity at the lower 
portion of the oesophagus if any alcoholic fluid, sugar, or food pre- 
pared from pure starch (which during digestion is transformed into 
sugar) is allowed to be taken. (Vide Stomach, the Digestion of 
Food, and the chapter on Mucous Membrane.) 
Pepsin is the albuminoid constituent of the gastric juice, con- 
verting food proteids (albuminous or nitrogenous substances) into 
peptones. Its action seems to be limited to the reduction and com- 
plete solution (digestion) of albuminous food, such as eggs, meat, 
cheese, gelatin, and vegetable glutinous foods, embracing the blood- 
forming portions of the vegetable and all the nitrogenous elements, 
such as the albumen, fibrin, globulin, and casein of animal food (ex- 
cept the fat—non-nitrogenous), and converting them into purified 
compounds termed peptones; which, in composition, resemble the 
substances from which they are derived. The conversion of the 
food substances is effected by the power of the pepsin, and their solu- 
tion by the acid of the gastric juice; they are disintegrated, softened, 
and their different atoms and molecules liberated, each class of 
atoms and molecules coming into closer relation, forming albumen- 
peptone, casein-peptone, fibrin-peptone, and others. As it is prin- 
cipally the pepsin of the gastric juice which effects these changes, 
the products are called peptones. It is generally conceded that 
this separation and formation of compounds, or peptones, takes 
place in the stomach; though, as previously stated, digestion is not 
completed in the stomach, but continues in the intestines. Here 
these peptones, coming in contact with the intestinal juices, are 
more finely broken up; for instance, the albumen-peptone, coming 
in contact with the pancreatic juice in the duodenum, is purified 
and becomes that true albuminose capable of absorption by the 
lacteals of the mucous membrane, after which it becomes a part of 
the serum-albumen of the circulating blood. Other peptones are 
similarly acted upon and absorbed. A natural peptone can only 
be produced by the action of the pepsin and the acid of the gastric 
juice in the stomach, and not by pancreatic juice, or any other or- 
gan or substance. Nature, in all its acts, is simple; therefore, it is 
only by misconstruing natural acts or their results that we go fur- 
ther from the comprehension of its laws. Physiological chemistry DIGESTION. 
53 
considers the peptones of milk, casein, albumen, and fibrin separ- 
ately. Analysis proves them similar in composition to the sub- 
stances they are derived from; therefore, the peptones constitute an 
intermediate stage between the food just entering the stomach and 
the substances absorbed, as dough constitutes the intermediate 
stage between flour and bread. The albumen-peptone lies between 
the albumen of the food and the albuminose ready to be absorbed; 
the fibrin-peptone, between the fibrin of food and fibrinose; like- 
wise, the other peptones. 
Lehman gave the name peptone to the dissolved proteids of 
food in the stomach, the solution being effected by the action of the 
pepsin and the hydrochloric acid. Landois tells us that “peptones 
represent the highest degree of hydration of the proteids.” Accord- 
ing to the Schweizerische Wochenschrift far Pharmacie, “the best test 
for distinguishing albumen from peptone is xanthogenate of potas- 
sium, which precipitates albumen in a neutral solution, only after 
the addition of an acid. Peptones are precipitated at once, as they 
already contain free acid.” The foregoing substantiates the asser- 
tion that peptones hold an intermediate state between the food en- 
tering the stomach and the substances dissolved, purified, and 
ready for absorption in the intestines; for the alkaline condition 
of the intestinal juices neutralize the acid, while the bile acts upon 
the pepsin. Again, the peptones undergo other modifications. In 
short, the peptones are not absorbed as such, but form the materi- 
als which, through the action of said secreted juices, become true 
albuminose, fibrinose, globulose, which enter the circulation, and 
these again undergo further changes, as will be noticed in the fol- 
lowing pages. 
It may be well not to lose sight of the difference between' “albu- 
men,” “albuminous,” “albuminose,” and “albuminoid”; as one com- 
pound cannot be the other; neither can one, in the processes of life, 
be used in place of the other. The first three mentioned have been 
partially considered already, but the following may further illus- 
trate them, and especially the last—the albuminoid. The change 
of albuminous substances into albuminose, fibrinose, globulose, and 
other solutions, as long as they remain in the alimentary canal, 
must be considered simply as a physical change (in this case a fine 
solution), since a 'physical change does not cause the loss of the 
identity of a substance. This is illustrated by the fibre of linen, 
which is identical with the fibre of the mature flax-plant; or by 
dissolved sugar in water which is identical with sugar in solid 54 
DIGESTION. 
form. When albuminous substances are transformed in the stom- 
ach into albuminose, fibrinose, or globulose, and have entered the 
circulation, then, by the protoplasm of the tissue cells (this includes 
blood-cells, or corpuscles), chemical changes and combinations 
take place, producing albuminoids (proteids). The protoplasm of 
blood-cells (corpuscles) produces the albuminoid haemoglobin; the 
protoplasm of the cells of the secreting organs, the albuminoids of 
digestive juices, such as ptyalin, pepsin, pancreatin, etc.; and the 
protoplasm of the cells of the solid tissues the albuminoids, myo- 
sin, chondrin, etc.; the blood furnishing the material for the secre- 
tions and the transformations. 
We have now arrived at a distinctive point. There are two 
classes of albuminoids—juices and solids—which are very distinct 
in their properties, but similar in composition, and act differently. 
Those of the juices act in dissolving and transforming, but exhaust 
themselves during the process; such as the ptyalin of the saliva, 
the pepsin, pancreatin, etc. Those of the solid tissues are solidi- 
fying, not transforming, and maintain themselves; such as the 
myosin of muscles, chondrin of cartilages, and others. The ani- 
mal solid albuminoids have some analogy to the alkaloids of the 
plants, such as quinia of cinchona bark, or strychnia of nux vom- 
ica, excepting that the latter contain no sulphur. An albumi- 
noid is a nitrogenous compound, also called proteid (holding the 
first place); and is composed of C, 0, N, H, and S. In elementary 
composition the various albuminoids are alike, but differ in the 
number of atoms composing each. To illustrate: one albuminoid 
may contain more atoms of carbon, another of nitrogen, another of 
hydrogen, oxygen, or sulphur, and so on. Here we notice that the 
term “albuminoid” may indicate its derivation; but, as it is the 
product of a chemical change, it is not identical with the substance 
from which it is derived. This is illustrated in invisible coal-gasr 
which is obtained from visible solid coal. Chemical action separ- 
ates the atoms, which then unite with others; the molecules and 
substance formed lose their identity. Now, the food and certain 
fluids entering the body and containing the essential elements, 
may properly be called protein bodies, or substances out of which 
the numerous protein compounds (albuminoids) are formed in the 
economy; such as the ptyalin, pepsin, pancreatin, myosin, and 
others. The average albuminoid compound is, chemically consid- 
ered, very complicated, containing about 54 per cent of carbon, 22 
of oxygen, 16 of nitrogen, 7 of hydrogen, and 1 of sulphur. The DIGESTION. 
55 
various proteids formed in the body from the food protein com- 
pounds differ only in their atomic proportions, and exist naturally 
in the body, either in a semi-solid or in a solid condition, some 
of them being easily changed into a more or less insoluble state 
by a process termed coagulation. This coagulation is brought about 
in fibrin, for instance, by simply allowing the fluid containing its 
elements to escape from a vessel of the body; other substances 
containing an albuminoid, coagulate either by boiling, by contact 
with mineral acids, or with numerous other substances (such as 
the pepsin in contact with bile). The pepsin of the gastric juice is 
precipitated by contact with bile; hence, if bile enters the stomach, 
it either disturbs the digestion or causes vomiting. 
Indigestion is often the result of an imperfect secretion of acid 
or of pepsin; weakness of the mucous membrane of the stomach; 
or of fermentation, due to micro-organisms; either one of which 
changes the process of digestion into an abnormally increased acid 
condition, gas being evolved at the same time. All substances that 
contain much tannin, when taken into the stomach, also retard 
the digestive process. The rapidity with which watery solutions— 
for instance, of iodide of potassium, the alkaline carbonates, lac- 
tates, citrates, and hepatic remedies—pass into the blood, thence into 
the liver, urine, and saliva proves that the capillary veins of the 
stomach take them up; and, as they are tributary to the portal 
vein, the absorbed matters pass directly to the liver and stimulate 
it to increased secretion. 
The mucous membrane of the alimentary canal is not the only 
channel through which nutritive or other substances may be intro- 
duced into the system; as water, and substances dissolved in it, 
may get into the circulation by absorption through the skin. When 
no food can be taken into the stomach for some time, life may be 
sustained by enema, or by bathing in milk, bouillon, etc. In this 
case, the lymphatics of the skin absorb the fluid food and carry 
it into the blood circulation. It may be here observed that a chem- 
ical change of such nutritious substances before absorption is not 
necessary; but a thorough solution simply is required. The 
lymphatics (lacteals) of the intestine have the advantage of posi- 
tion to absorb the nutritious substances more thoroughly than the 
lymphatics of the skin. Food in the alimentary canal is, with re- 
spect to the bodily tissues, yet outside the confines of the body, as 
a fly inclosed by the leaf of an insectivorous plant is yet outside 
the tissues of the plant itself. The cells of the lacteals are dis- 56 
DIGESTION. 
posed to busy themselves during the digestive process with absorb- 
ing the more intricate materials, such as albuminose, fibrinose, and 
fatty emulsion; while the capillary veins of the intestinal wall 
absorb not only venous blood, but also glycogen, or saccharine mat- 
ter, and discharge them into the portal vein. 
That the stomach does not dissolve or digest itself may find an 
explanation in one or more of the following four circumstances: 
1. No digestive pepsin is secreted when the stomach is empty. On 
administering pepsin or some other artificial digestive substance 
when the stomach is empty, the mucous membrane is attacked 
(provided a free acid is present), and pain results; this may also 
happen when the dose of pepsin is too large, with little food in the 
stomach. 2. The alkalinity of the blood, which circulates copiously 
in the layers of the wall of the stomach, counteracts an attack 
by the normal acid of the gastric juice. 3. Vital activity opposes 
the digestion of the stomach by itself, so that the chemical force 
of the pepsin and acidity of the juice are expended on the non-living 
food matter. 4. The indestructible transparent columnar epithe- 
lial cells of the gastric mucous membrane afford a natural protec- 
tion against the self-digestion of the stomach. If, on the other 
hand, at the completion of the gastric digestive process, the stomach 
contains much pepsin and an abnormally increased amount of acid, 
and the blood circulation is abruptly stopped, the gastric juice may 
then act on the stomach, digest, and perhaps perforate it. This 
may be of importance in a medico-legal sense. 
Intestinal Digestion.—Chyme, or liquefied food, when pass- 
ing from the stomach, is a mixture of the disintegrated or partly- 
digested food, some portions of which are completely liquefied, 
others not. In the intestine the bile, pancreatic and intestinal 
secretions act upon the chyme, thus continuing the digestion unfin- 
ished by the stomach, transforming the chyme into chyle, which 
is an opaque, milk-like fluid; and, when absorbed into the lacteals 
it consists of oil-globules, with albuminous matter emulsified, and 
fine, fatty granules, termed the molecular basis of chyle. 
After the chyle has passed through the lymphatic glands of the 
mesentery it also contains fibrin and white corpuscles (leucocytes), 
derived from these glands. It is obvious, therefore, that chyle 
gradually undergoes changes during its passage from the intestine 
through the lacteals and lymphatic glands. When it reaches and 
enters the thoracic duct it mingles and becomes identified with 
the lymph. DIGESTION. 
57 
The Duodenum is the immediate intestinal continuation from 
the stomach, the pyloric sphincter and orifice being the dividing line. 
It is from ten to twelve inches long. At a point about four inches 
from the stomach, the excretory duct (ductus communis choledochus) 
of the liver and gall-bladder enters and empties itself. Just below 
the orifice of this common bile-duct is the orifice of the larger pan- 
creatic duct, and a short distance below this is the orifice of the 
smaller pancreatic duct. The jejunum and ileum have no distinct 
line of demarkation between them. The duodenum, jejunum, and 
ileum together are about five times as long as the human body. The 
jejunum is so called from the fact that it is generally found empty. 
The Wall of the Intestine (Fig. 8) is composed of four tis- 
sue layers—a serous externally, a mucous membrane internally, 
and between these two a submucous connective tissue, and a mus- 
cular-fibre layer. The muscular layer is arranged in diagonal, 
longitudinal, and transverse layers of muscular fibres; their alter- 
nate contraction and relaxation producing the so-called peristal- 
tic action, which propels the intestinal contents forward. The 
presence of food in the intestines is the appropriate stimulus to 
excite the sensory cells of those parts. These cells communicate 
freely with the sympathetic centre-cells and 
those of the medulla oblongata. In this man- 
ner reflex actions are effected, producing the 
peristalsis, or alternate contraction and relax- 
ation of the muscular fibres in the wall of 
the intestine. The mucous membrane of the 
small intestine is thickly covered with villi, 
which, at their surface, are lined with a layer 
of epithelial cells (A, A, Fig. 7; andB, Fig. 8). 
When the liquefied food (chyle) passes along, 
each villus is completely submerged in the 
chyle. The villi are evidently intended not 
only as absorbent agents, but also to increase 
the absorbent surface. Each villus is supplied 
with a set of blood and lacteal vessels, the 
latter discharging into lacteal follicles beneath. 
The villi are most highly developed in the 
duodenum, where the chyle is first formed. 
They are turgid, enlarged, and opaque during 
the process of digestion,but in prolonged fast- 
ing become shrunken from inactivity and diminished nutrition. 
Fig. 7. 
Diagram of a Villus. 
A, A, Epithelial cells. 
B, B, An arterial capil- 
lary and a capillary 
vein. C, Lacteal vessel. 58 
DIGESTION. 
These villi are very active agents during the process of absorption 
of chyle in the small intestine, which has about 6000 square centi- 
metres of surface, with from 15 to 18 millions of villi at least. In 
the layer beneath the villi of the mucous membrane of the small 
intestine are found the follicles of Lieberkiihn (C, C, Fig. 8), uni- 
form and parallel with one another, and opening between the villi 
on the surface of the mucous coat. These follicles are abundantly 
distributed in the small intestine, and possibly effect important 
changes in the digestive process. In the submucous coat (E) are 
small glandular clusters termed Glands of Brunner (D, D). 
Fig. 8. 
MUCOUS 
COAT. 
SUB-MUCOUS 
) COAT. 
MUSCULAR 
SEROUS 
COAT. 
Diagram of the Wall of the Small Intestine, 
A, A, Villi. B, B, Epithelial layer. C, C, Follicles of Lieberkiihn. 
D, D, Brunner’s glands. E, Submucous coat. M, Muscular coat, 
resting on the serous coat. N, N, Ganglion cells. 
They are found only in the duodenum, and are most abundant at 
its pyloric end. From the vesicles composing a cluster arise mi- 
nute ducts, which coalesce and form a larger duct, through which 
the secretion of the gland passes into the duodenum. 
The Glandulae Solitarise, or Solitary Glands (B, B, Fig. 
9) are distributed throughout all parts of the small intestine. They 
are most numerous in the jejunum. These glands are simple, mem- 
branous, flask-shaped vesicles, the neck being even with the inter- 
nal surface of the intestine, while the rounded base lies within the DIGESTION. 
59 
mucous membrane. These glands consist of granular particles, and 
have no openings. The manner in which they discharge their con- 
tents is not clearly understood. The solitary gland is never larger 
Fig. 9. 
Diagram of Solitary Glands in the Mucous Membrane. 
A, A, Villi. B, B, Solitary glands. C, Layer of longitudinal mus- 
cular fibres. D, D, Brunner’s glands in the submucous layer. 
than a mustard seed. Possibly, when attaining this its maximum 
size, it bursts and its contents escape. The mucous membrane of 
the small intestine presents also numerous transverse folds, termed 
Valvulse Conniventes (Fig. 10). When a piece of this mem- 
brane is placed in water, the 
folds may be seen to move like 
the opening and closing of a fan. 
Each fold occupies three-fourths 
or more of the circumference of 
the mucous membrane and often 
projects more than half an inch 
into the intestine, supporting the 
villi, and checking somewhat the 
rapid motion of the intestinal 
contents. 
Peyer’s Glands are aggregations or clusters of solitary glands, 
forming oval patches. They are situated on the internal wall of the 
ileum, just opposite the attachment of the mesentery, and are small- 
est toward the jejunum, and largest near the caecum. In the latter 
situation patches occur measuring from two to three inches in the 
long diameter. They vary in number from fifteen to twenty. Re- 
garding the function of Peyer’s glands, nothing certain is known; 
though, as they become enlarged during the digestive process, it is 
inferred that they in some way influence this process. It is also 
surmised that the peculiar odor of the feces may be due to the 
Fig. 10. 
Diagram showing the Valyulje Con- 
NIVENTES OP THE SMALL INTESTINE. 60 
DIGESTION. 
presence of their secretion. In typhoid, or enteric, fever and in 
phthisis, these glands become irritated, produce acidity, and gener- 
ally ulcerate. This is probably the cause of the diarrhoea so com- 
ic <Tn in these diseases. 
The villi and the secreting follicles and glands in the wall of the 
small intestine are nourished by blood from the capillaries of the 
superior mesenteric artery. The branches of the arteries and veins 
in the gastric and intestinal mucous membrane are surrounded by 
a sheath of connective tissue, very strong along the arteries, but 
delicate along the veins. These branches lay within the muscular 
coat of the intestine in an oblique direction. On account of the 
weakness of the veins, they are easily compressed by the contrac- 
tion of the intestinal muscular coat during peristaltic contractions, 
thereby impeding the return of the blood from the gastric and 
intestinal mucous membranes, and increasing their congestion. 
The congestion continues as long as the contraction lasts, and is 
aggravated by frequent repetition. This condition of congestion 
is, to the digestive process, of the greatest importance, as it favors 
the longer retention of the blood in the walls of the stomach and 
of the intestine, enabling them to furnish more material for follicu- 
lar and glandular secretions. In health, the mere presence of food 
in the stomach and intestines excites the contractions of their walls, 
alternating with relaxations—peristalsis. These movements exert 
a favorable influence upon secretion and absorption by favoring 
not only the movement of the ingesta, but also by producing alter- 
nate compression and relaxation on the glands and follicles, thereby 
favoring the flow of their secretion, and in the villi the flow of their 
absorbed fluid. This demonstrates, also, that the congestion or peri- 
odic hypersemia brought about during the peristaltic contractions 
is really a physiological fact of vital importance. On the other 
hand, severe irritation of the intestinal walls brings about acidity 
and severe tonic contractions, resulting often in diarrhoea. In 
this case the mucous membrane secretes acid instead of mucus, and 
the natural secretions of the glands and follicles are diminished 
and the digestive process seriously retarded or entirely suspended. 
Should excessive irritation occur in the small intestine, the blood- 
serum, with the albuminous substances, alkaline salts, and water 
already absorbed, pass from the absorbent vessels back to the 
intestinal canal, and are carried forward by strong peristaltic 
movements so rapidly, that absorption in the large intestine cannot 
keep pace with it, and diarrhoea ensues. In cholera the irritation DIGESTION. 
61 
is most severe and fatal, because the blood thickens and as a result 
circulates sluggishly. 
The mucous membrane of the large intestine is smooth and 
shining, and is destitute of villi; it is provided, however, with 
absorbing and excreting cells. In the walls of the stomach and 
intestines, the capillaries of the gastric and the superior and inferi- 
or mesenteric veins, respectively, are very active as absorbents. 
Hunger and Thirst are peculiar sensations of desire mani- 
fested by thetissues of the body; hunger is referred to the stomach, 
thirst to the tongue and throat. When normal, these sensations 
indicate a want of the elements of food or drink in the tissues—- 
hunger calls for food, thirst for water. When the tissues become 
satisfied, these sensations disappear The natural demand of the 
appetite affords the surest criterion of the quantity of food or drink 
required by the system. CHAPTER Y. 
LIVER, BILE, AND PANCREATIC JUICE. 
The Liver is the largest glandular organ in the body. It is sit- 
uated beneath the diaphragm, in the epigastric and right hypo- 
chondriac regions, and is retained in position by five ligaments. 
Its size and weight are enormous when compared with other secret- 
ing glands. The weight of all the salivary glands together is only 
about three ounces, of the pancreas about two and a half ounces, 
while the liver weighs from three to fcur pounds. Its substance 
is divided into two large lobes, consisting internally of very 
small lobules, about l-18th of an inch in diameter, and composed of 
clusters of acini. The interlobular connective tissue, or sheath, 
finally surrounding the lobule is called Glisson’s capsule, being a 
continuation of the fibrous investment of the liver. 
The Bile-secreting Apparatus consists entirely of glandu- 
lar cells (acini) and blood-vessels. The cells occupy the lobules, 
and are from about 1-1100th to l-900th of an inch in diameter, 
each cell having a distinct nucleus. The cells are arranged in rows 
or columns within the lobule, and separated from the capillary ves- 
sels by a filmy membrane. At the periphery of the lobule this 
membrane coalesces and becomes continuous with the lining of the 
intralobular bile-ducts, which form a network at the sides of the 
cells. The liver is supplied with blood from two sources simulta- 
neously—the hepatic artery and portal vein (Fig. 11). 
The Hepatic Artery is a branch of the coeliac axis. It supplies 
nourishment to the liver, to the walls of its vessels (ducts, arteries, 
veins, and lymphatics), and the arterial blood from which, principal- 
ly, the hepatic cells secrete the bile. The red blood-corpuscles, which 
were decomposed in the spleen, then pass to the portal vein, furnish, 
in their oxygen, haemoglobin, and other elements, important constit- 
uents to the composition of the bilirubin and salts of the bile. 
The Portal Vein is formed by the union of four large veins— 
the gastric, splenic, superior mesenteric, and inferior mesenteric. The 
portal vein conveys to the liver the venous blood from the stomach, 
spleen, pancreas, and large and small intestines. It also supplies the 
liver with glycogen, albuminose elements, organic and inorganic salts. 63 
LIVER, BILE, AND PANCREATIC JUICE. 
The glycogen is transformed into liver-sugar. In the substance of 
the liver the portal vein subdivides after the manner of an artery. 
Its branches run between the lobules, and are termed interlobular 
branches. They surround the lobule and anastomose. The portal 
vein has its origin and termination in capillaries. Its capillaries 
in the liver communicate with the intralobular or central veins, 
situated in and passing through the central axes of the lobules. 
Fig. 11. 
Diagram of the Hepatic Blood and Bile Vessels 
(The organs in the diagram are separated, in order to show the ves- 
sels. In the natural position, the liver partly overlaps the stomach; 
and the hepatic artery is a branch of the cceliac axis. This diagram 
is simply to indicate the four principal vessels entering and depart- 
ing from the liver.) 
A, Liver. B, Stomach. C, Heart. D, (Esophagus. E, Spleen. 
1, Portal vein. 2, Hepatic artery. 3, Ductus communis choledochus. 
4, Gall-bladder. 5, Hepatic vein. 6, Duodenum. 7, Inferior vena 
cava. 8, Descending aorta. 9, Capillary veins of the stomach dis- 
charging into the portal vein. 10 and 11, Capillary veins of the in- 
testines, emptying into the portal vein. 12, Capillary veins of the 
spleen, discharging into the portal vein. 13, Iliac arteries. 
From these central veins and from the arterial capillaries the root- 
lets of the hepatic veins arise. Thus an artificial injection into 
either the hepatic artery or portal vein is apparent in the hepatic 
veins. Some hepatic cells have the function of secreting bile, while 
others transform glycogen into sugar; thus the blood, as well as 
the nutritive materials, in passing through the liver, are changed. 
The albuminose elements absorbed by the capillary veins (mesen- 
teric veins) of the intestines differ from the albumen in the hepatic 64 
LIVER, BILE, AND PANCREATIC JUICE. 
veins. Furthermore, by the secretion of bile, the non-nitrogenous 
portion of the arterial blood is removed, just as the effete nitroge- 
nous portion is separated and given off by the kidneys. The liver 
protects the body; substances just absorbed, but not fit for the cir- 
culation, are by the liver destroyed and excreted. 
The liver has a receptacle (storehouse) called the Gall Bladder, 
in which the bile temporarily accumulates. During the process of 
digestion the bladder contracts and discharges the bile into the duo- 
denum. That glvcogenous materials undergo important changes 
in the liver, may be inferred from the fact that the hepatic veins 
contain more pure blood-sugar than there is of glycogen in the por- 
tal vein. The hepatic veins contain also more white blood corpuscles 
than the portal vein but less haemoglobin, albumen, fibrin, and salts. 
Pure Bile has a clear, yellowish-brown or greenish color, de- 
pending on the relative amounts of bilirubin and biliverdin pres- 
ent. It has a bitter taste, and is neutral in reaction. Its specific 
gravity ranges from 1020 to 1025. Bile is composed of:— 
Water 859.2 
Solids—Bile salts (organic) 91.5 
Inorganic salts 7.7 
Fat 9.2 
Cholesterin 2.6 
Mucus and coloring matters 29.8—140.8 
1000.0 
Bile is continuously secreted, but only completely when, at proper 
intervals, food enters the stomach and digestion goes on in the ali- 
mentary canal. During long-continued fasting some of its material 
is wanting, in which case the secreted bile cannot be entirely 
normal. The secretion is most abundant during digestion, 
when absorption of food in the intestinal canal has begun. The 
bile in the capillary bile-ducts and the blood in the capillary blood- 
vessels are conveyed by capillary peristaltic action. (Vide Capil- 
lary circulation in chapter on Circulation.) The flow of blood and 
bile in the larger hepatic vessels is assisted by the respiratory move- 
ments of the diaphragm and abdominal muscles, compressing and 
relieving alternately the portal and hepatic veins, thus favoring 
the functional activity of the liver. The two hepatic veins convey 
the blood and sugar from the substance of the liver, and carry it 
into the inferior vena cava; while the bile ducts collect and pass 
the bile into the hepatic duct, thence into the duodenum. 
The daily secretion of bile in an adult is from about one and a 
half to two pints. It is undoubtedly antiseptic to the contents of 
the intestine, as when its contents are not acted upon by the bile LIVER, BILE, AND PANCREATIC JUICE. 
65 
the feces have a putrid odor. Bile is decomposed in the small in- 
testine and gradually diminishes in quantity; its salts are absorbed, 
so that normally in the large intestine no biliary salts are found. 
Obstruction of the bile ducts leads to extreme costiveness, showing 
that bile is a natural purgative. An abnormally increased quan- 
tity of bile causes diarrhoea. When no bile enters the intestines the 
dissolution, emulsifying, and absorption of fat are incomplete, and 
the want of bile salts in the blood results in impaired nutrition 
and consequent reduction in the weight of the body. 
The mucus secreted by the cells of the mucous membrane in the 
walls of the bile-ducts gives to bile a sticky consistency. Any 
slight resistance to the outflow of the bile from the liver, such as 
catarrh of the bile-ducts, or a superabundance of mucus on the 
mucous membrane of the intestinal canal, extending to the hepatic 
ducts, causes biliousness. If the obstruction be more serious, though 
the bile may be properly secreted, and its discharge merely inter- 
fered with—as by a plug of mucus, a gall-stone, or a tumor, which 
increases the pressure within the ducts, and enlarges the liver— 
then the lymphatics of the liver (not the veins) absorb the bile, 
which then passes by way of the lymphatics to the thoracic duct 
and into the blood, resulting in jaundice. This condition is always 
accompanied by extreme constipation, owing to the want of bile in 
the intestines. When bile has entered the blood, the pulse is gen- 
erally below normal—60 to 40 beats per minute—accompanied by 
slow respiration, and the temperature is lower than normal. This 
condition is caused by the bile in the blood weakening the sensi- 
tiveness of the endothelial cells of the internal lining of the heart, 
so that stimulation by the carbonic acid of the blood on these cells 
is diminished, and the result is insufficient stimulation for nervous 
reflexes on the heart. The administration of veratrin or aconitin, 
especially the former, acts also on cells by diminishing their sensi- 
tiveness, just as an ether-spray on the skin diminishes the sensitive 
function of the organum tactus. 
If the solid constituents of bile, especially the cholesterin, be 
in excess in the liver, and solidify, biliary calculi, or gall-stones, 
may be produced. At birth, by the ligation of the umbilical cord, 
the haemoglobin in the ligated vessels is converted into bilirubin, 
generally producing jaundice in the infant for the first few days. 
In health the glandular cells of the liver contain oil, in small 
globules. If in disease they accumulate to excess, the result is 
known as fatty degeneration of the liver. When bile enters the 66 
LIVER, BILE, AND PANCREATIC JUICE. 
stomach, it results in vomiting, as the bile is incompatible with 
pepsin. In administering hepatic stimulants, it is well that the 
bowels be kept open; otherwise, the bile, as such, may be reab- 
sorbed in the intestine. 
Hepatic remedies are generally absorbed by the capillary veins 
of the stomach. These veins discharge into the portal vein. Lan- 
dois notes the influence of drugs on the secretion of bile in dogs: 
“Podophyllin, aloes, colchicum, euonymin, iridin, sanguinarine, ipe- 
cacuanha, colocynth, sodium phosphate, phytolaccin, sodium ben- 
zoate, sodium salicylate, dilute nitro-hydrochloric acid, ammonium 
phosphate, and mercuric chloride (corrosive sublimate) are all 
more or less powerful hepatic stimulants, through their direct 
action on the hepatic cells; while scammony, colocynth, jalap, 
sodium sulphate, and baptisin, act on both the liver and the intes- 
tinal follicles and glands. Among substances which stimulate 
these follicles and glands, but not the liver, are castor oil, calomel, 
magnesium sulphate, gamboge, ammonium chloride, manganese 
sulphate.” Acetate of lead directly depresses the biliary secretions. 
The action of bile in the economy is five-fold, viz.— 
1. To assist the process of emulsifying fatty matter in the intestines. 
2. To assist in the absorption of fats by the lacteals of the villi. 
3. To moisten and additionally stimulate the intestinal walls to 
peristaltic movements. 
4. Its taurocholin and glycocholin, when absorbed in the intes- 
tine, furnish the blood with most important atomic elements. 
When they are not so absorbed the body emaciates. 
5. Its antiseptic properties prevent putrefactive changes in the 
intestines. (Vide Ptomaines.) 
Liver Sugar.—That part of starch which is not transformed 
into glucose by digestion is changed into glycogen, which becomes 
sugar as soon as it reaches the liver. That sugar is there formed 
is proven by the fact that if in the portal blood which supplies the 
liver no sugar appears, yet if supplied with glycogen sugar is found 
in the hepatic veins leading from the liver. Sugar is, therefore, 
formed by the transformation of starch during digestion, and from 
glycogen in the liver. 
Sugar in Blood.—The proportion of sugar in normal blood 
is about two parts sugar in a thousand parts of blood, and possibly 
a portion of this, in passing through the liver unchanged, may be 
the sugar found in the hepatic veins when no glycogen enters the 
liver, as claimed by some physiologists. (Vide Sugar in chapter 
on Nutrition.) In the normal condition of the system a lim- LIVER, BILE, AND PANCREATIC JUICE. 
67 
ited quantity of sugar undergoes changes in the blood, and is 
entirely decomposed; but if from any cause its quantity is ab- 
normally increased, it is then found in the urine. A diabetic con- 
dition may result from an unusual amount of sugar being taken 
with food, or from anything which hastens the circulation of the 
blood through the liver, or from an oversupply of blood to the liver, 
as in continued struggles, convulsive muscular action, forcible com- 
pression of the abdominal organs, or injuries. Again, if the cir- 
culatory centre at the floor of the fourth ventricle in the medulla 
oblongata be abnormally irritated, it increases the nervous reflex 
impulses to the abdominal and hepatic circulation, and sugar may 
then be found in quantity in the blood and urine. This condition 
may, on account of some disturbance in the circulation, be only 
temporary; if permanent, it is called diabetes mellitus. This latter 
affection is generally progressive and fatal, the urine being in- 
creased in quantity, of abnormally high specific gravity, and con- 
tinuously charged with sugar, which may continue to appear even 
when no saccharine matter is taken with the food. 
The Nerve-fibres supplying the Liver are derived from 
the hepatic plexus, which is formed by nerve-fibres from the coeliac 
plexus of the sympathetic nervous system and some fibres from 
the left vagus and right phrenic nerves. The fibres of the hepatic 
plexus accompany the hepatic blood-vessels, and supply their walls 
and the secretory cells. The normal sensitive stimuli for continual 
bile-secretion is derived from the carbonic acid of the venous blood 
in the liver. This sensation is conveyed through the vagus fibres 
to the medulla oblongata, where it is reflected and efferent (motor) 
impulses are conveyed through the phrenic nerve back to the liver 
for its action—similar to the reflex stimuli to the lungs or heart. 
Artificial stimuli or depressors (medicines affecting the liver) may 
increase or diminish these hepatic actions. ( Vide Carbonic Acid in 
chapters on Respiration, and Circulation.) 
The Lymphatics of the Liver form both superficial and 
deep networks. The superficial tymphatics are found in the tissue 
beneath the mucous membrane of the bile-ducts; the deep accom- 
pany the blood-vessels to the sides of the hepatic cells. 
Pancreatic Juice.— The Pancreas is a lobulated gland (A, 
Fig. 12). In structure it is like the salivary glands, but much 
larger. It lies transversely in the upper part of the abdomen; its 
right end is in contact with the duodenum (C). Its ducts (1) run 
through it centrally from end to end, receiving by their branches 
the secreted pancreatic juice and emptying it (2) into the duode- 68 
LIVER, BILE, AND PANCREATIC JUICE. 
num, just below the pylorus. The biliary duct (3) from the liver 
also enters the duodenum, a little above the orifice ot the larger 
pancreatic duct. In this manner the bile and the pancreatic juice 
are mixed with the chyme soon after it enters the duodenum. 
About ten ounces of pancreatic juice are secreted daily by an adult 
Fig. 12. 
Diagram of the Pancreas and Spleen. 
A, Pancreas. B, Spleen. C, Duodenum. 
1, Pancreatic ducts. 2, Orifices of the pancreatic ducts. 3, Bile 
duct. 4, Orifice of the bile duct. 5, Splenic artery. 6, Splenic vein. 
7, Capillary vessels in the spleen. 8, Indicating the passage of food 
from the stomach to the duodenum. 
during the digestive processes; but none in the intervals between. 
Its principal chemical constituent is an albuminoid substance 
termed pancreatin, constituting about ten per cent of the pancreatic 
juice. Zamanski, who made a careful examination of healthy 
human pancreatic juice, reported it to be a somewhat tenacious, 
yellowish, turbid liquid, with a marked alkaline reaction. 
His analysis gave the following results:—■ 
“Water 86.50 
Organic compounds (including albuminoid substances 9 2-4ths, 
extractive matter 3 3-4ths. Of the latter nitrogen constitutes 
about 1 l-12th part) 13.25 
Salts (sodium carbonate, chloride, phosphate, and sulphate; 
potassium, calcium, and iron), about 25 
100.00 
At a temperature of 100° F. (38° C.), this panereatic juice readily- 
converted starch into glucose, egg-albumen into peptone [albu- 
minose ?], and olive oil into an emulsion.” (Vide Peptone in 
chapter on Digestion.) 
Fatty materials are not changed in the stomach; but melted by 
its warmth, and set free from the vesicles and fibres of the food. 
As soon as this fat comes in contact with the pancreatic juice, the 
emulsifying process takes place, after which it is ready to be ab- 
sorbed by the lacteals and to pass into the circulation. The pan- 
creatic juice also converts into glucose those starchy substances 
that escaped the action of the saliva and passed unchanged into LIVER, BILE, AND PANCREATIC JUICE. 
69 
the duodenum, the pancreatic juice possessing this power in a far 
higher degree than saliva, thus preparing starchy matter for the 
final sugar refinery—the liver. ( Vide Starch and Fats in chapter 
on Nutrition.) * 
Vessels of the Pancreas.—The pancreas is supplied with 
arterial blood from numerous branches of the splenic, pancreatico- 
duodenal branch of the hepatic, and superior mesenteric arteries. 
The veins discharge into the splenic and superior mesenteric veins, 
which are tributary to the portal vein. The lymphatics com- 
municate, eventually, with the thoracic duct. 
Nerves of the Pancreas.—The nerve-fibres of the pancreas 
are from the solar and splenic plexuses. Its afferent fibres run 
within the pneumogastric nerve, its efferent in the phrenic nerve. 
The Spleen (E, Fig. 11; and B, Fig. 12) is a ductless gland, 
concave and oblong in form, soft, and of a dark bluish-red color. 
Considering its size, it is the most vascular organ of the body. In 
the adult it is about five inches in length, four in breadth, one and 
a half in thickness, and weighs about seven ounces. It is situated 
in the left hypochondriac region; its upper portion is in close prox- 
imity with the diaphragm. It is held in position by a reflection 
of its peritoneal covering, termed the suspensory ligament. Its upper 
inward surface is in close contact with the cardiac portion of the 
stomach, adhering to it by the gastro-splenic omentum. Its lower 
inward surface is in close contact with the pancreas. The spleen 
is invested with two coats, a serous (peritoneal) externally, and a 
fibrous elastic coat beneath. Its nutritive supply is derived from 
the blood of the splenic artery. Its venous blood is conveyed by 
the splenic vein to the portal vein, which conveys it to the liver. 
The pulp of the spleen is made up of blood-corpuscles, granular 
matter, nucleated bodies (splenic corpuscles), and colorless nucle- 
ated cells in size from l-7000th to l-6000th of an inch. These, 
together with the intercellular membranes, form its parenchyma. 
Numerous lymphatic vessels arise from the proximity of the splenic 
corpuscles. 
Physiologically, the spleen is not absolutely necessary to life. It 
has often been removed from animals, and by accident destroyed 
in man, without perceptible loss of health after the wound had 
healed. Still, its functions are manifold. It has been surmised 
that the spleen is: 1. A diverticulum, or reservoir, of nutritious ele- 
ments for the blood, to be used during fasting. 2. The broken-up 
red blood-corpuscles impart the separated elementary substances 
to the venous blood of the portal vein. 3. To be a storehouse for 70 
JjIVER, bile, and pancreatic juice. 
albuminous matter, to be drawn upon and used during fasting. 4. 
To have the function of selecting and aggregating fibrin elements, 
as shown by the blood of the splenic vein, which sometimes con- 
tains four to six times the quantity of fibrin found in the venous 
blood elsewhere. 
That the spleen produces new blood-corpuscles is a conjecture 
not yet confirmed. The fact that the white corpuscles found in the 
vessels leading from the spleen are in excess of those found in the 
vessels supplying the spleen, may be accounted for by assuming 
that one function of the spleen is the changing of some of the red 
corpuscles into white corpuscles. The haemoglobin and oxygen 
released from the red blood-corpuscles in the spleen pass on to the 
liver, and there enter into the formation of bilirubin, that constit- 
uent of bile which gives it its characteristic color. 
The parenchymatous intercellular structure of the spleen allows 
great extension, forming diverticula, thereby serving to relieve the 
portal vein from undue distension under various circumstances. 
When the secreting function of the liver is enfeebled, or its ducts 
more or less blocked up, the spleen is always found enlarged. If 
the intestinal canal be distended with food, it may cause pressure 
on the portal vessels; then the speen enlarges. Again, it is large 
and distended after the process of chymification—say, from one to 
three hours after food is taken. It is manifest, therefore, that the 
spleen furnishes the liver with elements necessary for the pro- 
duction of bile, not only during the process of digestion, but also 
during the periods when no food enters the body. In prolonged 
fasting the spleen becomes correspondingly small, showing that 
it gives off its superfluous accumulation of blood to the liver to 
furnish material necessary for the continuous secretion of bile, as 
necessity requires. The spleen is, therefore, a reservoir for the 
blood, the quantity of which is increased when food is taken; for 
the superabundance of nutritious elements to the blood entering 
the blood-vessels at once, would endanger health if no provision 
were made for a storehouse—the spleen. • As soon as the absorbing 
and secreting organs have relieved the general blood pressure of 
the system, the spleen gives up its surplus, and regains its previous 
dimensions. This indicates that, if the spleen be removed, or its 
powrerof distension be impaired, there is liability to apoplexy. Such 
a condition may be relieved most quickly by venesection. When 
from any cause the peripheral circulation becomes enfeebled (chills), 
or there is a functional derangement of the liver, as in malaria, 
the spleen enlarges. CHAPTER VI. 
SECRETION AND EXCRETION. 
Secretion is the function, possessed by certain classes of cells, 
of absorbing atomic elements from the blood, and transferring 
and combining these elements into one or another of four forms of 
new compounds — solids, semisolids, fluids, or gases. The solids 
we find as collagen, chondrin, etc.; the semisolids as mucosin, myo- 
sin, etc.; the fluids as saliva, gastric, pancreatic, and intestinal 
juices, bile, tears, perspiration, urine, milk, and serous fluids, etc.; 
the gaseous as carbonic acid gas in expired air. Secretion is effected 
solely by cells, as certain cells of bones, muscle-fibres, membranes, 
follicles, glands, and walls of ducts. The products of some of 
these secreting cells are deposited in the tissues, as the collagen, 
chondrin, and myosin; others are for immediate action, as the 
saliva, gastric and intestinal juices and fluids; others, again, are 
excreted, as urine and perspiration. Some of the secreting-cells are 
somewhat isolated, as those of bones and of muscle-fibres; others 
side by side, as those of mucous and serous membranes, Lieber- 
kiihn’s follicles, and ducts; others, again, in grape-bunch form, as 
those of Brunner’s glands, the pancreas, and salivary glands. The 
secreting glands are divided into two great classes; viz., those with 
ducts, and those without. To the former glands belong the lach- 
rymal, salivary, sudoriparous, mammary, sebaceous, Brunner’s, the 
liver, pancreas, kidneys, and testes; while the latter include the 
suprarenal capsules, spleen, thymus, thyroid, pituitary, and sol- 
itary glands. Some secreting glands are racemose in form, or grape- 
bunch-like, such as the salivary, and Brunner’s; others appear as a 
solid organ, as the liver and kidneys. In most cases the secreting 
cells derive the materials necessary for their own nourishment and 
for the elaboration of their ultimate products from the arterial 
blood only; while others derive the materials necessary for their 
secretions from the venous blood also, as the secretions of the cells 
of the liver, lungs, kidneys, and skin. The various secretions are 
not found, as such, in the blood, hut are products of the activity 
of the protoplasm of the cells, attracting, selecting, and aggregating 72 
SECRETION AND EXCRETION. 
the necessary atoms and molecules from the blood, and thus form- 
ing, according to the peculiarity of each class of cells, the various 
compounds—secretions. Hence, the phenomenon of secretion and 
the formation of new products is a function of the cells, and not a 
mere filtration from the blood. 
The secreting organs are supplied with two classes of nerve-fibres. 
These fibres are alike in structure, but carry different kinds of im- 
pulses; viz., sensory and motor. The sensory nerve-fibres convey 
Fig. 13. 
MUCOUS 
MEMBRANE. 
SUBMUCOUS 
COAT. 
MUSCULAR 
COAT., 
SEROUS 
COAT. 
Diagram of Secreting Follicles. 
A, A, Follicles. B, Ganglion of the sympathetic system. C, Nerve- 
fibre communicating with the medulla oblongata. 1), D, walls of the 
follicles containing columnar epithelial cells secreting the principal 
active substance of digestive juice. E, E, Epithelial cells lining the 
mucous membrane. 
impulses inward (afferent) from the secreting organ to the medulla 
oblongata, which, by reflex action, sends out an impulse (efferent) 
through one or more motor fibres to the appropriate organ or 
organs. The motor nerve-fibres carry four kinds of impulses; viz., 
vaso-motor (constrictor and dilator), inhibitory, secretory, and 
trophic. The impulse through the vaso-motor regulates the distri- 
bution of blood in the capillaries of the organ; the impulse through 
the inhibitory fibres diminishes or suppresses its activity; others 
regulate the activity of the secretory cells; and still others, the 
trophic, regulate the nutritive activity of the organ. Transmission 
of impulses through the three first mentioned motor-fibres takes 
place during secretory activity only, wdiile the fourth, or last, is 
most active during the repose of the organ. That the transmission 
of impulses through each class of nerve-fibres named is independ- 
ent of that of every other class, is proven by the fact that one kind 
of impulse may be defective or incomplete, or the nerve-fibre para- 
lyzed, while the others remain intact and unimpaired. Again, a SECRETION AND EXCRETION. 
73 
secreting organ may become congested, and lose the secreting power, 
though, normally, secretion is carried on when the organ is more 
or less congested. The motor fibres (vaso-motor, inhibitory, secret- 
ory, and trophic) from the medulla oblongata pass directly through, 
branch from, or reticulate with the sympathetic plexuses, and are 
thereby enabled to communicate simultaneously with one or many 
secreting organs. 
The impression received from a stimulus on the end-organ of a 
sensory nerve in a secreting organ is produced by contact with for- 
eign matter, though the individual may not be cognizant of it, 
as the cerebral convolutions are not directly connected with the 
function of any secreting organ. The medulla oblongata is thus 
connected, how'ever, so that whenever a secretory organ becomes 
active or inhibited by mental influence, the mind can act only 
reflexly through the medulla, similar to stimuli from a secreting 
organ. Consequently, any form of stimulation from the mind, for 
secretion or its impairment, must be considered a reflex act through 
the medulla. The presence of food or a foreign substance in the 
mouth, or even the smell of a favorite dish, provokes the flow of 
saliva; the presence of this food or substance in the oesophagus, 
stomach, and intestines, stimulates their secretions, as well as, 
indirectly, those of the liver and pancreas; while the presence of a 
very hot drink in the oesophagus and stomach, or mental excite- 
ment or depression, may cause perspiration. The afferent nerve- 
fibres from secreting organs pass through sympathetic ganglia 
before arriving at the medulla oblongata, similar to the manner in 
which all afferent (sensory) fibres pass to cerebro-spinal centres; 
while the efferent (motor) fibres from the medulla oblongata to 
secreting organs all pass to or through sympathetic plexuses before 
entering the organs. The activities of the elements, cells, and tis- 
sues cause a rise of temperature in the secreting organ, venous 
blood issuing from the organ, and in the newly formed product. 
The temperature, therefore, is higher in them than the temper- 
ature of the arterial blood supplying the organ. 
There are four fluids in the body with an acid reaction; viz., gas- 
tric juice, urine, perspiration, and the mucus of the vagina; all 
others have an alkaline reation; i. e., the blood-plasma, lymph, 
milk, tears, saliva, mucus, the serous, spermatic, intestinal, and 
pancreatic secretions. A characteristic of all secretions that are 
useful in the economy is that they have an alkaline reaction, except 
the gastric juice, and even this becomes neutralized; while those 74 
SECRETION AND EXCRETION. 
which are acid, and so remain, must be removed, as their accumu- 
lation in the body would prove deleterious to health. 
Excretion (evacuatio) is the separation, emission, or expulsion 
from the body of materials which have become useless, constitut- 
ing the effete matters or waste products (except the feces) of the 
various chemical changes and decomposition of the tissues. These 
materials, which have been a part of the tissues, by continual 
changes are no longer useful to the system, hence are collected by 
the absorbent vessels (lymphatics and veins), and carried by the 
blood to proper places for elimination; for example, the urine, car- 
bonic acid gas, and perspiration. The salivary and mammary 
glands are secretory in their function, while the lungs, liver, kid- 
neys and skin are secretory as well as excretory organs. The urine 
is secreted by the cells of the tubuli uriniferi in the cortical por- 
tion of the kidneys, but its expulsion takes place through the ure- 
thra. It is claimed by some that the separation of urine from the 
blood is simply a filtering process brought about by the blood’s 
high pressure in the glomerules of the kidneys. This cannot be 
altogether true, however, for the following reasons, given by Yeo, 
to-wit: 
“1. Urine differs much from the fluid obtained by filtering the 
blood. 
‘*2. In health, the urine contains no albumen, a substance in 
which the blood is rich. 
“3. Urine contains comparatively much more urea and salts 
than the blood. 
“4. Why should simply water and salts, without albumen, pass 
through the capillaries of the glomerules and not through any 
other capillaries?” (For further demonstration see chapter on 
Kidneys.) 
The due performance of the functions of excretory organs is 
essential to the well-being of the body, for the following reasons: 
The peculiar anatomical and chemical composition of the tissues 
of the body renders them liable to continuous decomposition and 
decay. Consequently, it is a positive necessity that the decom- 
posed matters be rapidly carried off. Every physical, mental, and 
chemical operation causes disintegration, or breaking up, of certain 
portions of the tissues, resulting in the accumulation of effete 
matter, which, with the decomposed food and food excess, would, 
if not speedily removed by the excretory organs, cause the blood 
soon to become poisoned. CHAPTER VII. 
THE ABSORBENT SYSTEM. 
The absorbent system consists of capillary veins and lymphatics. 
The absorbents take up materials from the intestines and tissues, 
and carry them into the general circulation. (The Venous Sys- 
tem is described in the chapter on Circulation.) 
The Lymphatic System consists of vessels, glands, and the 
thoracic duct. The vessels ramify and extend throughout nearly 
all parts of the body, and possess the function of absorbing the 
chyle from the intestines, and the lymph from other organs and 
tissues, conveying them into the venous system. Lymphatics lead, 
like veins, towards the heart. The lacteal vessels, originating in 
the villi of the intestines, pertain to and are a part of the lymph- 
atic system. They absorb and convey the chyle to the follicles 
beneath the villi, thence pass through lymphatic glands, and dis- 
charge into a much-dilated lymphatic vessel known as the receptac- 
ulum chyli (1, Fig. 14). This dilatation is the commencement of 
the thoracic duct, and is formed by the junction of the two lumbar 
and intestinal lymphatic trunks, just in front of the second lum- 
bar vertebra, between the abdominal aorta and inferior vena cava. 
The lacteals are so termed because the chyle, which they absorb 
from the alimentary canal, is milky in appearance. 
Chyle is the product of digestion. It is found in the small in- 
testine and the lacteals. In order that digested food may be of use 
to the entire economy the nutritious materials pass through the mu- 
cous membrane of the alimentary canal, so as to obtain admission 
into the blood. Its endosmosis through the villi and mucous mem- 
brane is facilitated by the alkaline condition of the intestinal juices. 
It passes into the thoracic duct and mingles with the white lymph, 
entering the general circulation at the left subclavian vein. The 
mucous membrane of the intestine, and the vessels therein, are 
lined with cells endowed with the function of controlling the pas- 
sage of liquids and liquid foods through them, and of elaborating 
new juices. Consequently, these cells are divided into two classes—- 
one for secretion, the other for absorption. The former are the cells 76 
THE ABSORBENT AND LYMPHATIC SYSTEM. 
of the follicles of Lieberkiihn and glands of Brunner. These absorb 
from the arterial blood the material for the secretion of the intes- 
tinal juices, which are discharged into the intestinal canal. The cells 
of absorption are those of the intestinal capillary veins and lacteals, 
which absorb and promote the passage of nutritious substances 
from the intestines to larger veins and lacteals. 
The oleaginous matter of the 
chyle is in a. state of emulsion; 
i. e., suspended in minute par- 
ticles in the nutritive fluid, like 
fine granulated dust. These fine 
fatty granules constitute the 
molecular basis of the chyle. The 
white color and opacity of chyle 
depend upon the molecular con- 
dition of the oily ingredients. 
During digestion the capillar- 
ies of the lacteal vessels be- 
come distended. As soon as the 
digestive process is over, and the 
contents of the lacteals are dis- 
charged into the thoracic duct, 
the lacteals again contract. 
Chyle is not therefore constantly 
present. The products of diges- 
tion are carried by two different 
routes—by the portal vein, and 
by the lacteals—into the general 
circulation. The vena porta 
carries the blood from the portal 
system, which contains glycogen, 
to the liver, wrhere it traverses 
the capillary vessels and is 
transformed by the cells of that 
organ, and the product is con- 
veyed by the hepatic veins to the 
inferior vena cava, thence to the right auricle of the heart. The 
lacteals absorb the chyle and convey it to the thoracic duct, which 
carries, besides the chyle, the lymph of the trunk and lower extremities. 
The chyle contains the largest proportion of albuminose, fibrinose, 
and fatty ingredients derived from the ingesta. The thoracic duct 
Fig. 14. 
Diagram of the thoracic duct. 
1, Beceptaculum chyli. 2, Thoracic duct. 
S, Left subclavian vein. 4, Left internal 
jugular. 5, Eight subclavian vein. 6, Eight 
internal jugular. 7, Eight vena innominata. 
8, Left vena innominata. 9, Superior vena 
cava. THE ABSORBENT AND LYMPHATIC SYSTEM. 
77 
contains, besides the lymph and chyle, the white blood-corpuscles 
derived from lymphatic glands. The latter are especially numerous 
on the lacteal vessels of the mesentery, through which the chyle 
flows on its way to the thoracic duct. All these substances become 
modified after entering the blood, and, except the water and some 
of the salts, are no longer recognizable under their original form. 
Water may be absorbed from the intestines in an almost unlimited 
quantity. A weak solution of common salt may become partly 
absorbed; but if salt elements be present in the solution in great 
quantity, as in large doses of sulphate of magnesium, absorption ie 
then stopped, and even reversed. In this case, instead of the fluid 
parts of chyle passing inward by endosmosis, exosmosis takes place,, 
causing thereby copious watery stools. With fat there is a similar 
phenomenon. A small quantity is absorbed by virtue of the alka- 
linity of the intestinal juices and the presence of pancreatin; if 
however, fat is present in excess, it acts as a laxative and passes off 
with the feces. 
Lymph is the fluid in the lymphatic vessels absorbed from the 
tissues of the body. It is a whitish yellow, transparent, juice-like 
liquid, salty to the taste, alkaline in reaction, and having a specific 
gravity of 1022. It is composed of water, fibrin, albumen, fat, and 
salts. It coagulates like blood when withdrawn from the vessels;, 
that is to say, on account of the fibrin present, it separates into two 
parts—fibrin (a solid), and serum (a liquid). The same propelling 
influences are brought to bear on the lymph as on the venous blood. 
In the average adult, about sixteen and a half ounces, or about 2000 
grammes, are daily absorbed and conveyed to the blood. Lymph 
is derived from the metamorphosis of the tissues, and passes into 
the circulation, to be transformed in part into other matter, the 
residue being eliminated from the system by excretion. The lym- 
phatic vessels are very thin, delicate, and transparent, nearly uni- 
form in size, and somewhat nodulous, on account of their numerous 
valves—being similar in valvular structure to veins. These vessels, 
are arranged in two sets, the superficial and the deep. The former 
are found immediately beneath the skin, and join the deep set in the 
submucous and subserous areolar tissues. The deep lymphatic 
vessels accompany the larger blood-vessels. The lymphatic capil- 
laries originate in the tissues by plexuses, and lie between the plex- 
uses of capillary blood-vessels. There the various fluids transude 
from one set of vessels to another set; the arterial blood nourishing 
the intervening tissues, while at the same time the veins take up the 78 
THE ABSORBENT AND LYMPHATIC SYSTEM. 
blood, and the lymphatic vessels absorb the worn-out material. 
The molecular activities of the tissues, and the alternate contraction 
and relaxation of the muscular fibres during muscular activity in- 
crease the metamorphosis of the tissues and the quantity of lymph. 
Lymph Glands.—The lymphatic capillary vessels enter lym- 
phatic glands, which vary in size from that of a small pea to that 
of a small walnut, and are situated in the course of the lymphatic 
vessels (Fig. 14). Lymph contains white blood-corpuscles, formed 
in the lymph glands, and are carried away by the stream of lymph 
flowing through the glands. These glands are very numerous in 
the neck, axilla, chest, abdomen, and especially in the mesentery 
and groin. In the latter situation the glands sometimes become 
inflamed, and bubo results. Lymphatic vessels are found in nearly 
all parts of the body, the exceptions being the cornea, the vitreous 
humor of the eye, and the peripheral epithelial coverings. 
The chyle of the abdomen and the lymph of the left side of the 
body and arm, and of both legs, are conveyed to the thoracic duct, 
thence into the left subclavian vein (3, Fig. 14); while the lymph 
of the head, neck, and right side of the chest and arm, enters the 
circulation at the junction of the right subclavian and right inter- 
nal jugular veins (5, Fig. 14). In this manner all the absorbed 
substances of the body are collected, and become mingled with the 
venous blood, just before entering the right side of the heart. ( Vide 
Intestinal Digestion.) 
Osmosis is the interchange of liquids through organic mem- 
branes or tissues. Endosmosis is their passage from without 
inward; while Exosmosis is their passage from within outward. 
In the living body, the membranes and tissues are all fresh; and 
with the presence of fluid-matter containing sodium chloride, and 
the proper normal temperature, the conditions for endosmosis and 
exosmosis are present. Egg-albumen is non-osmotic; i. e., it does 
not pass by transudation through an animal membrane, on account 
of its adhesiveness and gelatinous consistency; nor does the albu- 
minous matter of the blood exude into the secreted fluids without 
being acted upon catalytically and dialytically. A certain press- 
ure is necessary to obtain the result. If the dialytic pressure in 
the capillary arteries be increased, while obstruction to the venous 
capillaries exists, the albumen transudes with the saline and watery 
parts of the blood, infiltrating the tissues of the affected part. In 
this way a collection of blood-serum in the cellular tissue under 
the skin takes place, called oedema, a general anasarca, or dropsy. CHAPTER VIII. 
THE BLOOD. 
The Blood is a red liquid that circulates through the cavities of 
the heart, arteries, veins, and capillary vessels. It consists of the 
liquor sanguinis, with minute red and white bodies, or corpuscles, 
floating independently in the liquor sanguinis in large numbers. 
The corpuscles form by weight about 45 per cent and the plasma 
about 55 per cent of the blood, or by volume about 60 and 40 
per cent, respectively. The specific gravity of the blood is 1055. 
It is slightly alkaline. 
Red Corpuscles.—Arterial blood contains about 6 millions of 
red corpuscles in each cubic millemetre. In form the corpuscle is 
a spheroidal biconcave disc, in size from about 6 to 8 micromilli- 
metres (l-3200th of an inch) in transverse diameter (1 and 2, Fig. 
15), and about l-6th of the transverse diameter in thickness (3). 
It has no external envelope and no nucleus, and is composed of 
water, albuminous and coloring matter, iron and mineral salts. It 
is jelly-like in consistency, and very flexible, and therefore easily 
elongated in the course of circulation, capable of twisting, bending, 
and passing through narrow and tortuous channels. In fact, it will 
pass through vessels having a smaller diameter than its own, regain- 
ing its original shape as soon as the pressure or traction is removed. 
Its form is determined principally by external influences; i. e., 
by imbibition of oxygen, fluid, or by tissue pressure. If water be 
added to the blood the red corpuscles absorb it by imbibition, where- 
upon they lose their concavity, and become pale and spherical. 
Strong alkaline solutions, such as sodium, potassium, or ammo- 
nium, dissolve the whole substance of the corpuscle with more or 
less facility. After circulating for a time through the capillaries 
they become dissolved in the liquor sanguinis. The red corpuscles, 
when examined shortly after being drawn from the vessels, adhere 
together by their surfaces, and appear like rolls of coin or rouleaux 
(1, Fig. 15). The white corpuscles, by an inherent power, constantly 
undergo change of form (4), in the same manner as the amoebse. 
The Haemoglobin, or red coloring matter, is the principal con- 
stituent of red blood-corpuscles, making up about 90 per cent of 80 
THE BLOOD. 
their substance. It is an albuminoid (proteid), completly formed 
within the corpuscles, possibly during the circulation of the blood 
through the right ventricle of the heart and through the capil- 
laries of the lungs. The haemoglobin of arterial blood consists 
of: Carbon, about 55 parts; oxygen, 21.85; nitrogen, 14; hydro- 
gen, 8; iron, 1; and sulphur, 0.15; including the two compounds 
globulin and hseviatin. During its circulation through the capil- 
laries of the tissues its chemical constituents change, so that the 
haemoglobin in the corpuscles of veins near the capillaries consists of 
carbon, about 70 parts; oxygen, 4; nitrogen, 18; hydrogen, 8. These 
changes of constituents and color are effected during the blood’s cir- 
Fig. 15. 
Diagram of Human Blood-corpuscles 
1, Red corpuscles lying in rouleaux. 2, As they appear when lying 
on their flat surface. 3, As seen from the side, exhibiting their 
double-concave form. 4, White corpuscles (leucocytes) exhibiting 
their changes of form and movements, as the amoebae. 
culation through the capillaries of the lungs and the tissues. Haemo- 
globin is a powerful absorbent of oxygen when in contact with the 
atmosphere. The bright red color of the corpuscles depends upon 
the quantity of haemoglobin and oxygen present. When pure haemo- 
globin is separated from the corpuscles and dissolved, it may be 
crystallized. It is dissolved haemoglobin which imparts to muscu- 
lar tissue its reddish color. 
The principal function of the red corpuscles is to carry oxygen, 
which they hold in loose combination. In certain of the lower ani- 
mals these corpuscles are larger though less numerous than in the 
human economy; hence, their vital functions are lower. In ani- 
mals whose red corpusles are small and numerous, the functions of 
respiration, circulation, nutrition, and motion are correspondingly 
increased. As the red corpuscles have no nuclei, they cannot be 
prepared by the blood; they are replenished by the transformation 
in the lungs of the young white corpuscles, wrhich originate in the 
chyle, lymphatic glands, spleen (?), and red marrow of bones, con- 
tinually passing into the great venous trunks. In the formation THE BLOOD. 
81 
of red corpuscles a fresh supply of oxygen is absolutely essential. 
The constituents of the blood are present only temporarily, as they 
undergo chemical changes continuously in the different organs and 
tissues. In 1000 parts of healthy normal blood about 790 parts are 
water and 210 solids, the latter including the corpuscles (134 parts), 
albumen (52), salts (8), fats (5), sugar (2), fibrin (3), and waste 
matter (6). By evaporating the 79 per cent of water from the 
blood, there remain 210 parts, or 21 per cent of solid residue, the 
ultimate chemical composition of which resembles that of muscles. 
When the red corpuscles are in excess in the blood, a pathological 
condition, or plethora, takes place, exhibiting itself in haemorrhage 
or local congestion. Should they become deficient in number, 
anaemia results. To these corpuscles belong the special function of 
taking up oxygen from the atmosphere or air in the lungs. They 
contain an intercellular fluid substance of denser consistency than 
the serum, which, from the fact of these corpuscles being in the 
blood, is classified as tissue. This tissue, above all others, changes 
its chemical constituents and replaces its losses most quickly. 
White Corpuscles.—Under normal conditions, the white cor- 
puscles are not so numerous as the red, being about 1 to 300. They 
are about l-4th larger than the red—i. e., about l-2500th of an inch 
in diameter—and are of irregular shape (4, Fig. 15). They con- 
sist of a soft, viscid, colorless, finely granular substance. Each white 
corpuscle has a nucleus, differing in this respect from the red corpuscle. 
A strong alkaline solution dissolves them. These corpuscles are en- 
dowed with amoeboid motion; i. e., they move very slowly, and some- 
times stop for a few moments and adhere to the internal surface of the 
vessel. When the circulation of the blood is normal the amoeboid 
movements cannot be seen; but if the blood be withdrawn from the 
vessel and kept at a normal temperature, they may be seen to change 
their shape, like the amoeba, by alternate contractions and relax- 
ations of their substance. Whenever the blood current in the vessels 
or tissues becomes obstructed or retarded, the white corpuscles ac- 
cumulate, and become more numerous in proportion to the red ones in 
the part affected. It is believed that the white corpuscles originating 
in the spleen (?), red marrow of bones, and in chyle become red by 
the absorption of oxygen in the lungs, but that those originating in the 
lymph-glands remain white; also, that the white corpuscles can pass 
through the walls of capillary blood-vessels into the surrounding 
tissue, where they form corpuscles of pus (pus cells), or inflamma- 
tory lymph, and so play an important part in pathological processes. 
6 82 
THE BLOOD. 
A poison working in the body cannot always be found in the 
blood—e. g., the poison of small-pox or vaccine lymph—though the 
pustules and lymphatics exhibit parasitic life. The presence of cocci 
in the blood in cases of measles seems to be an established fact, 
though the effect of an injection of measle-blood into a healthy per- 
son is yet in doubt; some experimenters have failed to produce a true 
measle disease, while others claim success. In this disease the num- 
ber of red blood-corpuscles is diminished, while the number of the 
white is increased. The blood appears thin, dark, with diminished 
fibrin, and in fatal cases may infiltrate and stagnate in the tissues. 
Blood-plasma is a transparent, colorless, homogeneous liquid, 
with blood-corpuscles held in suspension. In 1000 parts of plasma 
there are about 900 parts of water, 77 of albumen, 3 of fibrin elements, 
8.5 of other nitrogenous and organic substances, 2.5 of fat, and about 
9 of salts, such as sodium and potassium chlorides, carbonates, and 
phosphates, lime and magnesium phosphates. These salts are of 
importance to the system. They render the blood alkaline, a pre- 
requisite to nutrition, as its alkaline condition enables the blood- 
plasma to neutralize the acid (a form of lactic acid) of the various 
tissues. This reaction results in the generation of carbonic acid 
elements, which are carried to the lungs, skin, and kidneys. In 
these organs the carbonic acid gas is secreted and eliminated. ( Vide 
Carbonic Acid in chapter on Respiration.) The alkalinity of the 
blood also facilitates endosmosis, as well as the absorption of fatty 
substances, which could not otherwise take place, especially in the 
alimentary canal. For the purpose of nutrition the most impor- 
tant ingredients of the blood-plasma are the albuminous matters. 
The serum of the blood is derived from the products of digestion 
and absorption. The blood-corpuscles, as well as the secreted juices 
are elaborated by fixed organs, and depend on them for the main-, 
tenance of their normal condition; it is important, therefore, that 
these fixed organs perform their functions perfectly, a disturbance 
in any organ changing the normal composition of the blood and 
leading to a perversion of function called dyscrasia. A. dyscrasia 
of the blood itself is not common, the trouble arising generally in 
one or more of the fixed organs. 
The blood’s circulation diffuses the nutritious substances through- 
out the tissues, and conveys all the material to the parts where heat 
is generated, and supplies heat where lost by exposure. It also takes 
up and conveys waste products to the places of exit from the body. 
The rate of movement of the blood current varies. In the heart, THE BLOOD. 
83 
during its systole, or the contraction of the ventricles, its velocity 
reaches 1200 millimetres per minute; in the descending aorta, 300 to 
600; carotid arteries, 200 to 400; vense cavae, 200; radial arteries, 100; 
and capillaries, 5. The average velocity of the blood in the arteries is 
from 20 to 30 centimetres per second. The rapidity of the circula- 
tion is such that the blood makes the entire round of the body in an 
adult in about 30 seconds. The amount of blood in the system is 
much greater during the time of digestion than during the period of 
abstinence. Normally, it is about 12 per cent, or l-8th the weight of 
the body. In case of death from haemorrhage about one-fourth of 
the blood remains in the body. 
Each tissue absorbs from the arterial blood the particular mate- 
rials it requires for nutrition, such as fibrin by the muscles, fatty 
substances by the nerves, gelatin and earthy salts by the bones, 
while the milk cells (during lactation) separate albuminous, fatty, 
and saccharine substances. Owing to the abstraction therefrom of 
the elements of nutrition in the tissues and secreting processes, the 
blood in each organ undergoes an alteration in its constitution, 
rendering it for the same purpose, unfit for further use. The 
venous blood concentration and intermixture in the heart is, there- 
fore, rendered necessary to avoid deterioration and to maintain its 
normal composition. 
Matters entering the blood may be quickly and completely elimi- 
nated, or more or less retained, even for years exhibiting it effects. 
This is illustrated in the introduction of the poisons of vaccine 
virus, syphilis, and of other chronic diseases. That this persistency 
is due to the blood carrying the morbid matter is proven by the fact 
that the same kind and parts of tissues become affected in organs on 
both sides of the body or limbs, the same kind of tissue in other 
parts very often remaining unaffected; also, by the existence of a cer- 
tain adaptation, peculiar to each individual person, between the 
blood and the tissues. It seldom occurs that even the same kind of 
tissues become in all persons simultaneously, similarly, or as severely 
affected. Impure or bad blood depresses and weakens the nervous 
system especially, its gray matter being the most delicate of all 
tissues, and soonest affected by faulty or insufficient nutrition. 
In the disease termed chlorosis the red blood-corpuscles are 
considerably reduced in number, the blood appearing watery, though 
really having no more water than usual, and being lighter in color 
than when normal. This chlorotic condition does not depend on the 
disease or decay of these corpuscles, but upon their imperfect and 84 
THE BLOOD. 
insufficient reproduction. In most cases chlorosis is a congenital 
disease, depending on dyscrasia. It occurs most frequently in young 
females, exhibiting itself in fatigue, palpitation of the heart, pains 
in the back and hips, fermentation and flatulence in the stomach 
and bowels, and constipation and an unnatural appetite for chalk, 
lime, and other absorbents—all the symptoms indicating a weakness 
of the digestive organs and general debility. As the disease ad- 
vances the face and skin of the body appear greenish white, the 
feet become oedematous, and there is a condition of general anae- 
mia. 
Another disease simulating chlorosis is called leucocythaemia, 
which may more properly be termed leucocythamplio, indicating an 
abnormal increase in the number of white blood-corpuscles. The dis- 
ease is commonly known as the white-blood disease. In chlorosis the 
blood appears watery, in leucocythamplio white. In the latter dis- 
ease the relative proportions of red and white corpuscles is changed, 
so that instead of 300 there may be only 50, 20, or 10 of the red to 
one of the white, or they may even be equal in number. In this 
affection an increased production of white corpuscles in the spleen (?) 
and lymphatic glands takes place. This is shown by the fact that 
the veins and absorbent vessels which carry the blood and products 
from these organs contain not only more white corpuscles than under 
normal circumstances, but more also than the arteries that supply 
them. In leucocythamplio the spleen is always considerably en- 
larged (splenic tumor—hyperaemia). The blood in the vessels of the 
pulp of the spleen, as wrell as the contents of its lymphatic vessels, 
flowing more slowly, an accumulation takes place, and consequent 
swelling results. When the spleen has been distended for a time, 
an increase of new capillaries (hyperplasia), or enlargement of its 
entire structure, and overproduction of its white blood-corpuscles, 
follow. This leucocythamplic process, or swelling of the spleen, 
generally causes simultaneous enlargement of the lymphatic glands, 
which may lead to chronic inflammation of the peritoneal covering. 
The blood in malarial disease is deficient in albumen, fibrin, and 
red corpuscles, which explains the co-existing anaemic condition, 
palpitation of the heart, and oedematous condition of the skin. In 
this disease the liver and spleen are always enlarged, the enlarge- 
ment of the spleen being brought about by the damming up of the 
blood in the portal vein and its tributaries. Again, the blood is 
defectively developed, owing to the deranged state of the stomach, 
bowels, and blood-making organs. THE BLOOD. 
85 
The coagulation of blood depends on the presence of fibrin. 
Fibrin, though present in such very small quantity (only 3 parts 
in 1000 of blood), exhibits its great importance. When blood is 
gradually withdrawn from the blood-vessel, it is this fibrin which 
causes its coagulation. Fibrin, however, does not exist in blood as 
such. There are two substances—the globulin of the corpuscles and 
fibrinogen in the plasma—which unite to form the fibrin of the coag- 
ulum. A portion of the fibrinous elements of blood disappears in pass- 
ing through the capillary circulation, showing that venous blood 
contains less of these elements than arterial. In the liver and kid- 
neys it entirely disappears, so that none is found in the renal and 
hepatic veins. This demonstrates clearly that it is produced else- 
where, and is always of recent formation, its quantity remaining un- 
changed. When a congenital deficiency of fibrinous elements exists 
in the blood, no clot can form in a ligated vessel; so that if a liga- 
ture be applied and afterwards removed, bleeding begins again. 
Another ligature is likewise followed by a secondary hamiorrhage. 
In these cases of dyscrasia any slight wound or minor operation may 
be followed by a fatal haemorrhage. Fibrin elements are present 
also in chyle and lymph, which therefore coagulate like blood when 
withdrawn from their vessels. 
Before coagulation the blood consists of:- 
' Corpuscles. 
Fibrin. 
Albumen. 
W ater. 
Salts. 
Corpuscles 
Plasma 
containing the 
Coagulation changes it:— 
Corpuscles. 
Fibrin. 
Clot contains the 
Serum contains the ... 
Albumen. 
Water. 
Salts. 
In from 12 to 24 hours after death the blood generally coagulates, 
even in the heart and larger blood-vessels. During life it may coagu- 
late from local arrest or an impediment in the circulation in a particu- 
lar part. If blood be accidentally extravasated into the connective tis- 
sue, the substance of the brain, spinal cord, or serous cavity, or if the 
circulation in a blood-vessel stops, it coagulates. If a ligature be 
placed upon an artery (A 1, Fig. 16) the blood coagulates (2), the 
clot filling the vessel and extending from the ligature up to the near- 
est arterial branch (3) towards the heart—i. e., the point at which 86 
THE BLOOD. 
the circulation continues. The end (1) of the ligated vessel towards 
the periphery completely contracts. 
When the blood gradually coagu- 
lates upon the inner surface of the 
vessel it forms a partial thrombus 
(C 6, Fig. 16), through the open 
center of which it may continue to 
flow. A transverse section of such 
thrombus looks like a tube with 
thick walls (D). The thrombus 
may become complete, however, if 
the general circulation becomes so 
sluggish as to result in an increased 
deposit of fibrin. The materials 
of coagulated blood, after solidifi- 
cation, lose their original proper- 
ties, which cannot be restored, 
being similar in this respect to the 
albumen of a hard-boiled egg. 
A Thrombus is a clot of coagu- 
1 a t e d blood in a blood-vessel 
(B 4, Fig. 16) produced by the adhesion of fibrinous molecules one 
to another. Having strong mutual attraction when in contact, 
the molecules tend to expel with increasing force the fluid con- 
tained, thus forming fibrin. If a fibrinous formation take place in 
the circulatory apparatus, it usually assumes the shape of a conical 
plug, filling up the lumen of a small or medium-sized vessel towards 
the still open blood-current by a conical point, and creating thus an 
obstructing thrombus (4). The thrombus, then, is a foreign body. 
It may become absorbed, in which event it gradually diminishes in 
size, disappearing in a few days, or in as many months. 
Thrombi differ, however, in structure, the structural peculiarity 
depending upon the rapidity or slowness of formation. If an artery 
be ligated and the thrombus form rapidly, it consists of unstriated 
fibres mingled uniformly with red and w'hite corpuscles regularly 
dispersed; but if formed slowly, the wdiite corpuscles lay stratified. 
The red corpuscles, with the fibrinous material of the blood, form 
the principal mass of a thrombus, which, when the corpuscles part 
with their coloring matter (which quickly takes place), appears white. 
If a clot form in the pulmonary veins, or left side of the heart, it 
may pass either to the brain, at the middle cerebral arteries in the 
rig. 16. 
Diagram of arteries ligated and 
clotted. 
A 1, Ligation. 2, Clot. 3, Branch through 
which the blood continues to circulate. 
B 4, Thrombus. 5, Branch open like 3. 
C 6, Partial clot. D, Section through a 
partial clot. THE BLOOD. 
87 
neighborhood of the Sylvian fissure, to one of the kidneys, or it may 
lodge in the popliteal artery behind the knee; if formed in the venous 
system, or right side of the heart, it will enter the lung. If the clot 
be not larger than a blood corpuscle, it may easily pass to a capil- 
lary, but if it exceeds this size it will remain and occlude the vessel 
whose lumen, or size, it cannot pass, thereby producing an embolism. 
The blocking-up of a large vessel brings about an angemic condition 
of the organ affected; if the obstruction occurs in capillaries it soon 
produces excessive congestion, as they fill up from all sides with 
blood. The pressure may be high enough to produce haemorrhage 
by rupture of the vessels, the stagnation preventing nutrition of the 
part. At the height of typhoid fever the blood is very dark-colored; 
if coagulated, presenting a small and soft clot. In scarlatinal rheu- 
matism the blood is liable in certain parts to coagulate, so that in 
severe or fatal cases some of the peripheral arteries and larger veins 
are generally found to be blocked, the former with emboli, the latter 
writh thrombi. White blood-corpuscles have also a great affinity for 
each other. During health nothing but the rapidity of the blood- 
current prevents their adhering to each other and their excessive 
accumulation. CHAPTER IX. 
THE CIRCULATION. 
The digested nutritious substances which pass through the intesti- 
nal canal, are absorbed partly by the capillary veins, partly by 
the lacteal vessels, and carried into the general circulation by two 
great channels. The venous blood of tbe intestines, stomach, and 
spleen is carried to the liver, and from there into the inferior vena 
cava, which discharges into the right auricle of the heart; while the 
lacteal vessels carry the chyle into the thoracic duct, which dis- 
charges into the left subclavian vein at its intersection with the left 
internal jugular. In this way the nutritious fluids are mingled with 
the circulating blood. Arriving at a muscular pump (the heart), the 
blood is forced through strongly lined arteries, whose walls gradually 
become thinner as the branches grow smaller. At last it arrives at 
the delicate network of arterial capillaries, consisting of single mem- 
branous tubes, through which the nutritious substances of the blood 
ooze, and serve as nourishment for tissues. The remainder is carried 
by the capillary veins to larger and still larger veins, finally empty- 
ing into the heart. 
Dr. Harvey first described the circulation of the blood in 1628. 
The manner, however, in which the blood passed from the arteries 
to the veins still remained shrouded in mystery. Dr. Malpighi, who 
was born in the same year (1628), afterwards discovered, by the aid 
of a magnifying glass (microscope), the blood corpuscles, and the pas- 
sage of the blood from the arteries through the capillaries to the veins. 
The circulatory apparatus consists of four parts: 
Heart.—A hollow muscular organ which propels the blood. 
Arteries.—Membranous, elastic, pulsating canals which convey 
the blood from the heart to all parts of the body. 
Capillaries.—A network of minute tubes, which bring the blood 
in contact with all the tissues. 
Veins.—Vessels which receive the blood from arterial capillaries 
among the tissues and return it to the heart. THE CIRCULATION. 
89 
The Heart is a muscular structure suspended in a closed bag or 
sac termed pericardium. It is divided by a vertical and a trans- 
verse partition into four cavities—two auricles (A, B, Fig. 18), and 
two ventricles (C, D). The shaded portion (3, Fig. 17) is called the 
right, venous, or pulmonary heart, because it sends the venous blood 
to the lungs; the unshaded portion is called the left, arterial, or 
systemic heart, because it sends the arterial blood into the general 
system. The heart is thus the center of a double circulation—a 
lesser circulation of the 
blood, from the right half 
of the heart through the 
lungs to the left half; and 
a greater circulation, from 
the left half to the gen- 
eral system, the blood re- 
turning to the right half. 
Its size is about that of 
the closed fist, the average 
weight being about 11 
ounces in the adult male, 
and nine in the female. It 
is attached to the spinal 
column, and suspended 
somewhat freely in the 
cavity of the chest, its 
great blood-vessels passing 
through the mediastinum. 
The heart has eight ori- 
fices; four in the auricles, 
of which two are for the 
venae cavse(5 and 6,Fig.l8) 
one for the coronary vein 
in the right auricle, and 
one (properly four) for the 
pulmonary veins (9) in 
the left; two auriculo-ven- 
tricular (1 and 2) between the auricles and ventricles; one aortic (4), 
and one pulmonary (3). Six of these orifices have valves (the in 
ferior vena cava, the two auriculo-ventricular, aortic, pulmonary 
and coronary), which guard these orifices, in order to preclude the 
regurgitation of the blood. 
Pig. 17. 
]. The head. 2, Lung. 3, Heart. 4, Liver. 5, Spleen. 
6, Kidney. 7, Intestines. 8, Part of lower extremity. 
9, Part of upper extremity. 
Sketch of the blood circulation. 90 
THE CIRCULATION. 
In the right auricle, the inferior vena cava (5) is guarded by the 
Eustachian valve, while the superior vena cava (6) has no valve. 
The right auricle has also the valve of 
Thebesius, or coronary valve (not shown 
in Fig. 18), guarding the coronary 
vein at a point between the orifice of 
the inferior vena cava and right auric- 
ulo-ventricular orifice. The tricuspid 
valve is at the auriculo-ventricular ori- 
fice (1), between the right auricle and 
right ventricle. The orifice of the pul- 
monary artery (3), in the right ven- 
tricle, is provided with three semilunar 
valves. The orifices of the pulmonary 
veins (9), in the left auricle, have no 
valves. The mitral valve (2) guards 
the left auriculo-ventricular orifice. 
The aortic orifice (4), of the left ven- 
tricle, has also three semilunar valves. 
Thus the two.orifices of the vessels (the 
pulmonary artery and aorta, 3 and 4,) 
that have to stand the greatest press- 
ure are supplied with three valves. In 
some cases they have only two valves. 
The walls of the ventricles are much 
thicker than those of the auricles. That 
of the left ventricle is about four times 
as thick as that of the right, constitut- 
ing the greater part of the heart, and indicating the difference in 
proportion of work accomplished. The blood which nourishes the 
heart itself is supplied by the coronary arteries—two branches from 
the aorta immediately above the semilunar valve. This blood, after 
having discharged its function, is carried to the right auricle by the 
coronary veins, and has the shortest circulation of any in the body. 
The two venous blood streams of the venae cavae (5 and 6), in pour- 
ing into the right auricle, cross each other; i. e., the blood of the twro 
veins passes into the auricle downward and forward, thereby inter- 
mixing thoroughly. From this auricle it passes into the right ven- 
tricle with sufficient force to turn upon itself; then it is forced upward 
from that ventricle through the pulmonary artery into the lungs, to 
give up its carbonic acid and receive oxygen, thereby changing from 
Fig. 18. 
Diagram of the Cavities of 
the Heart. 
A, Right auricle. B, Left aur- 
icle. C, Right ventricle. D, 
Left ventricle. 
1, Tricuspid valve. 2, Mitral 
valve. 3, Semilunar valves of 
pulmonary artery. 4, Semilu- 
nar valves of the aorta. 5, In- 
ferior vena cava. 6, Superior 
vena cava. 7, Pulmonary art- 
ery. 8, Transverse aorta. 9, 
Pulmonary veins. 10, Descend- 
ing aorta. THE CIRCULATION. 
91 
venous into arterial blood. This arterialized blood passes on through 
the pulmonary veins to the left auricle, and downward into the left 
ventricle, where it makes another turn upon itself, and is forced from 
that ventricle upward, into the aorta, and through the entire arterial 
system. Thus the blood currents are forced through the cavities of 
the heart with a spiral or twisting motion, caused by the alternate 
contractions, with relaxations of its walls, termed cardiac pulsation. 
This produces two sounds. The first is distinguished by placing the 
ear to the chest over the fifth rib and fifth intercostal space, where 
the sound is loudest; the second, following the first almost immedi- 
ately, is heard best and most distinctly over the sternum at the 
level of the third costal cartilage, directly over the semi-lunar valves. 
The first sound is caused partly by the muscular contraction of the 
cardiac fibres and tension of the auriculo-ventricular valves, at the 
time of the ventricular contraction, but mainly by the apex of the 
heart striking against the inner wall of the chest. The second, or 
aortic sound, is caused by the sudden closure and tension of the 
aortic and. pulmonary (semi-lunar) valves, lasting half as long as 
the first. For one-fourth of the whole time of pulsation the heart 
is at rest. When its muscular fibres are relaxed the blood enters 
the cavities, causing dilatation, termed Diastole. At once the ven- 
tricles contract and forcibly expel the blood, termed Systole. Simul- 
taneously with the contraction of the ventricles the apex of the 
heart moves slightly from left to right, and so rotates upon its own 
axis, as it were. These movements of lateral inclination and. rotation 
are caused by the spiral arrangement of the muscular fibres in the 
wall of the heart. During the diastole, the transverse diameter of 
the heart increases and its length diminishes; while during the 
systole the reverse occurs. Each cardiac pulsation is a double con- 
traction and relaxation, the former commencing at the auricles, fol- 
lowed by the ventricles; then comes a short interval of repose. The 
auricular contraction is short and feeble, the ventricular being more 
powerful and lasting longer. These two forms of contraction do 
not alternate exactly, but are connected and continuous, appearing 
as one regular motion only, termed rhythm, and ranging from 70 to 
75 per minute in the adult. 
It may at first sight appear absurd to state that the respiratory ac- 
tivity of the lungs and the pulsative activity of the heart are peri- 
staltic in their nature; i. e., incited to normal activity by or through 
local contact, the lungs by contact with carbonic acid and air, and 
the heart by contact with the carbonic acid of the moving blood—in 92 
THE CIRCULATION. 
short, that the primary physical or chemical stimulation for normal 
action in organs and cells is from local stimulation in all. As soon 
as we come, in our physiological inquiries, to consider more fully 
the simple laws of nature, and drop all explanations not based on 
fact, or not borne out by solid reasoning and deduction, we will be- 
gin to truly comprehend the physical laws of the human economy, 
and not before. No one has ever proved conclusively that either the 
so-called “vital spot” of the medulla oblongata, the spinal cord, 
pneumogastric nerve, cervical or cardiac plexus, or ganglia, are, 
singly or combined, the primary cause of the heart’s normal action; 
and this remark applies just as forcibly to the normal activities of 
the lungs. To say that all or any of said nervous organs are the 
'primary cause of the heart’s or lung’s activities, is to contravene the 
law of nature. No physical body possesses the innate power of 
changing its condition with reference to motion; this is caused 
only by another body’s power of producing motion. Take away 
from the heart the moving blood as a local stimulus, or the moving 
carbonic acid and air from the lungs, and they will cease to act, 
despite the efforts of all the nervous organs mentioned. The car- 
bonic acid stimulus on the right half of the heart produces a reflex 
impulse through the circulatory centre of the medulla oblongata 
on the entire heart, similar to the stimulus to the lungs, which pro- 
duces reflex impulses on the respiratory muscles. It might be ob- 
jected, in opposition to this view, that if we produce a slight lesion 
only at the “vital point” of the medulla, the lungs and heart will 
stop. So they will, but in either case it would be simply an inter- 
ference with the normal activity of these organs. Every argument 
must have a resting point, or point d'appui—a fact. All that is here 
claimed is that the primary cause of every normal activity of any organ 
or cell within the vital animal economy, other than psychical activity, 
pertains to sensation. Now, as no one has yet determined satis- 
factorily the primary cause of the normal activity of the lungs 
and heart, it is permissible to turn in another direction in our search 
for that primary cause. This we have done, and have come to the 
conclusion that it is found in the sensibility of the organs them- 
selves. Again, to every chemical or physical action, so far as motion is 
concerned, there is an equal and opposite reaction, which may reason- 
ably be termed peristaltic as regards the normal functional activity 
of an organ or cell in the manifestations of vital animal life. 
(Vide Capillary Action; Tactile Corpuscles; Pacinian Bodies; and 
External Sensation.) All normal actions of the nervous system on the THE CIRCULATION. 
93 
heart and lungs—in fact, on any organ of the body (other than 
nervous centres)—are of indirect origin, and any voluntary or in- 
voluntary nervous action, on body or limb, is through reflex only. 
The natural physical tendency of any portion of the body is that 
of contraction, cohesion, and rest; consequently, the normal state 
of sphincters is contraction and rest, and simple touch, locally 
applied, increases their contraction; or, when the nervous system 
acts upon them, through an opposite reflex action, the sphincters 
dilate. Though this is necessary for the ejection of excrementitious 
substances and for the comfort of life, the nervous action is in each 
case reflex as regards the organ acted upon. The sphincter has been 
selected as a good illustration simply. The stimulus of light on the 
retina acts similarly in effecting a reflex impulse on the iris, though 
in this case for the purpose of contraction. 
It is not, by any means, the object of this argument to belittle 
the importance of the nervous system; for in the higher animal 
it performs a higher function than any other organ or system of or- 
gans. Through it all the activities of the body are reflected and 
the organs brought into harmonious and sympathetic relationship. 
The sole object here sought is to point out that the nervous centres are 
not, in a single instance, the primary cause of normal organic actions 
outside of themselves; and that these centres have their own local 
action simply, just as other organs have, brought about by their 
own irritability and sensitiveness, when the proper stimulus is ap- 
plied. Thus is revealed the missing link—the phenomenon of low 
animal organic life existing without a nervous system. All the 
laws of nature, although not fully understood, are simple. The 
shortcoming of our reasoning powers is nowhere better illustrated 
than in the laws governing our own body. For hundreds of years 
the best scientific minds have been occupied in explaining these 
laws, and still many of them are not even yet fully understood. 
This deficiency can lie only in the fact that we do not adhere to the 
simplicity of the laws of nature and of life, but continually strive 
to introduce explanations as vague as they are unphilosophical and 
unreal. Through all the phases of organic nature, we are brought 
face to face with manifestations of a power above the merely phys- 
ical and chemical. Try to explain protoplasm and the activity of 
cells on merely physical or chemical grounds, or on both, and the 
question as to how the protoplasm and cells of the human economy, 
or other of the higher forms of animal life, become endowed with a 
power and activity superior to the alleged causes of their production, 94 
THE CIRCULATION. 
must certainly remain unanswered. There is but one solution, 
and this is based on the admission of a vital principle, or soul. The 
author does not deny that physical and chemical forces play their 
part in the phenomena of organic life, but he strenuously holds 
that there is a power and activity above and superior to these, and 
without which growth and nourishment—in a word, that activity 
so much beyond and distinct from the physical and chemical—can- 
not be accounted for. 
In Syncope, or fainting, there is failure of the heart’s action, 
causing a suspension of the circulation and an entire cessation of 
power in both brain and spinal cord, followed by more or less loss 
of sensation and muscular movement. Such a condition may also 
be brought on by some powerful emotion. The reflex actions of the 
nervous centres on the muscular system, respiratory and circula- 
tory apparatus, are, in such a case, interfered with. The heart is 
easily affected by sentimental emotions, collectively or separately, 
such as love, hate, joy, or grief, each of which is capable of inter- 
fering with the reflex actions. While the cells of the cerebral con- 
volutions are endowed with the power of receiving impressions 
through the sensation caused by the soul, and thereby affecting the 
heart, or any other organ—this, as in the case of an impulse from an 
external (organ) sensation, can only be through reflex action, in so 
far as the nerve impulses are concerned; for the cells of the cere- 
bral convolutions have no direct communication with any organ 
other than nervous centres, so that the stimulus from the vital 
principle causes an impulse on the cells of said convolutions, and 
the impulse is forwarded to another nervous centre, where it is 
reflected. If, for instance, the impulse be reflected from the corpora 
quadrigemina, it may cause a sense of darkness before the eyes; 
from the cerebellum, either activity or loss of muscular power; from 
the medulla oblongata, either increased action or impairment of the 
respiratory system, circulatory apparatus, or digestive organs; from 
the spinal cord, generally relaxation of the sphincters. 
Arteries distribute the blood outwardly from the heart through- 
out the entire body. The Aorta begins at the heart, and in its 
course gives off large branches (arteries), which subdivide into 
smaller ones, finally terminating in capillaries in the tissues. The 
Walls of the Arteries are composed of three coats: an inner, 
termed tunica intima, consisting of thin elastic laminae lined with 
a single layer of nucleated squamous cells; a middle, called tunica 
media, consisting principally of non-striated muscular fibres encir- THE CIRCULATION. 
95 
cling the vessel transversely; finally, an external coat, the tunica 
adventitia, consisting principally of elastic fibrous connective tissue. 
The principal anatomical distinction between the larger and 
smaller arteries is in the structure of their middle coat. In large 
arteries this coat consists mainly of thick connective and elastic 
fibrous tissue, which in the medium sized vessels is less in quantity, 
while in the smaller this layer consists exclusively of muscular 
fibres. The large arteries are therefore very elastic, with little con- 
tractility, while the smaller are very contractile, but less elastic. 
The capillaries consist of a layer of elastic connective tissue lined 
with nucleated squamous cells. 
The arteries possess two properties influencing the movement of 
the blood within; viz., elasticity and contractility. Elasticity is the 
property by which the interrupted or intermittent action of the 
heart is made equable and continuous, chiefly in the larger trunks; 
while contractility is more concerned in regulating the flow of blood 
in the smaller vessels. 
Arterial Pulsation is produced by the ventricular systole 
(contraction) of the heart, forcing the blood into the arteries and 
distending their walls by the pressure exerted, and the subsequent 
contraction of the arterial walls. There are, therefore, two forces 
contibuting to produce arterial pulsations—the heart’s contraction, 
and the elasticity and contracting force of the arteries. The arte- 
rial distension and elongation increases with age, and the arteries 
finally become permanently enlarged, especially in their curvatures. 
During relaxation of the ventricles of the heart, the semilunar 
valves close, and prevent any movement of the arterial blood back- 
ward. The blood is thus forced onward under the pressure of the 
arterial elasticity and peristaltic action into the smallest capillaries. 
(Vide Capillary Action.) When the arteries have become partially 
emptied they are again distended by another contraction of the 
heart, and by this successive expansion and relaxation pulsation 
is produced. The blood flows much faster through the arteries than 
through the capillaries and veins. Its greatest velocity is in the 
aorta nearest the heart. The average velocity in the carotids is 
about twelve inches per second. As the blood approaches the cap- 
illaries the current diminishes in rapidity, owing to the mechanical 
friction on the arterial walls, also to the fact that the combined 
calibre of the capillaries largely exceeds that of the single vessel 
leading to them; so that in the capillaries the velocity is only about 
one and a half inches per second. No pulsation is perceivable in 96 
CIRCULATION. 
the capillaries, on account of their small size and plexus formation. 
The Pulse Rate in the foetus in utero is 142 per minute; in the 
new-born infant, 132; from 1 to 4 years, 105; at 15, 85; and from 
25 to 60, about 70 to 75. The rapidity of the heart’s motion is 
inversely to its power. Thus, a rapid pulse indicates a feeble action 
of the heart, and a normally full pulse a strong action. In hydro- 
cephalus the pulse may rise to 200 per minute, or in apoplexy fall 
to 80 or even to 20. (For certain abnormally slow pulsations, see 
Bile.) Sometimes we find a dicrotic or double pulse; i. e., two pul- 
sations of the artery for each contraction of the heart. One is 
caused by the impulse of the heart, the other by the unequal elas- 
ticity and distension of the artery. In typhoid disease, this con- 
dition of pulse is often present. Again, a dicrotic pulse does not 
always denote a diseased condition, for it sometimes exists in the 
healthy individual—in such a slight degree, however, that it can- 
not be detected with the finger. With the sphygviograph, or auto- 
matic register, it is observable. 
Veins are tubular canals which convey the blood from the cap- 
illaries of the tissues toward the heart. They are like arteries in 
structure, having three coats, an inner, middle, and exterior. These 
coats have the same names as those of the arteries. They differ 
from them, however, in containing fewer muscular and elastic fibres, 
but more connective and white fibrous tissues; showing that veins 
have more distensibility but less resistance than arteries. The 
veins, like the arteries, are found in all tissues (except in muscular 
fibres, the crystalline lens, vitreous humor, superficial layer of 
the cuticle, hair, and nails). The veins begin and form contin- 
uous channels from the minute capillary plexuses (Fig. 20). They 
may be divided (excepting certain venous sinuses within the skull) 
into two sets—superficial and deep. The latter generally accom- 
pany the arteries in one sheath of fibrous and elastic tissue. The 
smaller arteries are accompanied by a pair of veins, one on each 
side, termed venae comites. Immediately beneath the integument, 
the superficial veins discharge their contents into the deep ones, 
and all finally unite in two large trunks, termed superior and infe- 
rior venae cavx (5 and 6, Fig. 18), which open into the right auricle 
of the heart. The arterial portions of the capillaries give off and 
supply blood to the tissues, while the venous portion of the capil- 
laries carry the blood from them, whence it flows into larger veins. 
The pulmonary, portal, and umbilical veins act in the capacity 
of arteries. Veins through which the blood flows contrary to the CIRCULATION. 
97 
natural law of gravity are supplied with a great number of check- 
valves formed by a doubling of their internal lining membrane, 
pocket-like folds, or pouches (Fig. 19). The other veins, such as 
the superior vena cava, pulmonary, renal, portal, and hepatic, have 
no such valves. The venous valves permit the blood to flow readily 
toward the heart, but prevent it from returning toward the peri- 
phery. The flow of blood through the venous system depends on 
the favoring conditions of the veins and certain forces: 1. The walls 
of veins offer no resistance to the blood, as the lumen of veins in- 
creases as they approach the heart. 2. The 
alternate contraction and relaxation of the 
voluntary muscles exerts some pressure on 
the veins between the muscles. 3. The re- 
spiratory distension of the chest and descent 
of the diaphragm impel an onward move- 
ment. 4. The suction caused by the expan- 
sion of the right auricle of the heart. 5. 
Capillary peristaltic action. (Vide Capillary 
Action.) 
In the venous circulation of the stomach, 
spleen, pancreas, and intestines the blood 
does not enter the vena cava directly. The 
veins of these organs unite in one large ves- 
sel, the vena porta, which enters the liver, 
where it branches out like an artery, subdividing into a capillary 
network that permeates the whole mass of the liver, supplying con- 
siderable material from which the bile is secreted, and to which the 
arterial blood of the hepatic artery also contributes. Thus, the 
blood flowing through the portal vein passes through two sets of 
capillaries in the interval between leaving the aorta and entering 
the vena cava. 
The movement of the blood in the veins is only about one-third 
as fast as in the arteries. The capacity of the entire venous sys- 
tem is about two and a half times as great as that of the arterial. 
The Capillary Circulation is the most important feature of 
the circulatory movement. Through the capillaries a free inter- 
change between the blood and tissues takes place. The capillaries 
(capillus, a hair,) are minute blood-vessels, forming the connection 
between the terminal branches of the arteries and the commence- 
ment of the veins. In size they average about l-3000th of an inch 
Fig. 19. 
Diagram of the Valves 
in Veins. 
1, Valve open. 2, Valve 
closed. 98 
CIRCULATION. 
in diameter, and their arrangement varies in the different tissues. 
They pursue no definite course. In the muscular system they are 
somewhat parallel with each other; in the skin and intestines they 
form loops; around fat-cells they are arranged spherically (Fig. 20). 
When blood-vessels approach the capillary system they gradually 
diminish in size, first losing their external coat, the middle coat at 
the same time becoming thinner and gradually disappearing alto- 
gether. The inner coat alone remains, forming the capillary, a thin 
elastic fibrous connective tissue layer, lined with nucleated squamous 
cells. The walls of the capillaries are, therefore, soft and yielding, 
so that osmosis of liquids and gases can readily take place. The 
arterial as well as the venous capillaries form networks by free in- 
osculation, termed capillary plexuses. The largest capillaries are 
found in the secreting glands and osse- 
ous tissues; the smallest in the muscles, 
nerves, and retina. The smallest are 
about the size of the minutest red blood 
corpuscles. In each organ and tissue 
the inosculations of the capillaries dif- 
fer; in the organs of secretion and ab- 
sorption they are the most numerous. 
The combined calibre of the arterial 
and venous capillaries increases in di- 
ameter so enormously that it is about 
800 times as great as that of the parent 
trunk; consequently, when those circu- 
latory vessels have divided and subdi- 
vided into capillary networks, the 
heart’s action on those vessels becomes 
indistinct, and no pulsation in the capillaries is perceptible. 
The Capillary Circulation is Peristaltic; but, on account 
of the minuteness of the diameter of the capillary, it is difficult to 
illustrate the rapid alternation of contraction and relaxation which 
takes place. From a likeness of effect we argue a likeness of cause. 
Hence, the manner in which fluid matter is propelled through the 
capillaries cannot be contrary to that in other tubes of the animal 
economy with a similar function. In the chapter on “The Senses” 
it is stated that sense-organs are endowed with the power of react- 
ing to appropriate stimuli. The presence of blood in the capillary 
causes normal peristaltic action, similar to the action of the ingesta 
in the alimentary canal, blood in the heart and arteries, lymph in 
Fig. 20. 
Diagram of the Capillary 
Circulation. 
a, Artery, b, Vein, cc, Ar- 
terial capillaries, e e, Venous 
capillaries. CIRCULATION. 
99 
the lymphatics, and urine in the ureters. When the position of the 
body is reversed (the head downward and the feet upward) the con- 
tents of the stomach continue to pass into the intestine by virtue of 
the peristaltic action of the oesophagus, which the closure of the 
cardiac orifice alone cannot prevent. Again, in this position of the 
body the urine persists in flowing to the bladder, the intestinal con- 
tents towards the anus, and the blood to the feet, though not with 
the same force, as the position of the body is unnatural. That the cir- 
culation in the animal capillaries is peristaltic may be further illus- 
trated by the fact that when an object gives off matter it becomes 
smaller, while the object attracting or absorbing it becomes larger, 
for no two particles can occupy the same space at the same time. 
The capillary is fed continuously, and the blood in the capillary 
cannot recede in the normal condition on account of the arterial 
force on the blood and the capillary peristaltic action forward. The 
capillary gives up nutritious substances to the surrounding absorb- 
ing cells, which in their activity must alternate in dilating (taking 
up matter) and contracting (giving off matter to the tissues), so 
that the dilation and contraction of the cells in the delicate wall of 
the capillary produce the peristaltic action in the animal capillary, 
caused by the presence of blood. Experience illustrates these facts, 
that when the contractility of the arterial portion of the capillaries 
is relaxed (dilated) in any part of the body, for a longer or shorter 
period of time, an inflammation of the part results correspondingly. 
On the other hand, when the venous portion of the capillaries ab- 
normally contract the blood accumulates, causing inflammation, 
which is accompanied not only by an increased quantity of blood 
in the capillary vessels, but also by an increased temperature. 
The following points may be considered in relation to the in- 
adequacy of the heart’s action to the capillary blood propulsion: 
1. A slight change (peristalsis) is noticeable in the capillary cal- 
ibre in the frog’s foot. 2. Secretions, such as sweat, may occur after 
the heart ceases to heat. 3. In certain animals of the cold-blooded 
type the capillary circulation has been noticed to continue- for some 
time after the heart was excised. 4. Animals, even the foetus, have 
been produced without a heart, with all the other organs well 
developed. The illustrations of the reflex requisite for capillary 
action through nerve-fibres and nervous centres are similar to those 
given in the chapters on the “Mucous Membrane”, “Secretion, 
and Absorbents.” 
Capillary Action.—The so-called capillary action of plants 100 
CIRCULATION. 
and of dead matter, be it organized or not, cannot properly apply 
to capillary action in the vital animal economy; for in the former 
there is no sensation and no peristalsis, but simply molecular and 
atomic attraction, cohesion, and adhesion. Thus a piece of soft 
wood, a sponge, a towel, a piece of sugar, etc., become wet through- 
out when a small part of them is dipped in water. 
Organs and secreting glands, during their activity, become ex- 
cited, and more blood passes through them; but during activity 
the nourishing blood for the tissue of the organ or secreting gland 
retains its arterial color even to the veins; hence, the nourishment 
of the tissues of the organ or gland takes place only during repose, 
when the arterial blood becomes venous, while in the muscular 
system the greater the activity the darker the venous blood. In 
paralysis, in complete muscular repose, or complete etherization, 
however, the venous blood of the part affected has the color of the 
arterial. As the blood yields to each organ and tissue the material 
required for either nutrition or secretion, the venous blood return- 
ing from each organ or tissue is consequently altered in composi- 
tion. In fact, the venous blood being no longer fit for the same 
purpose, it is returned to the heart to become there intermixed, 
and, not only in the heart, but also in the lungs, to receive new 
material. ( Vide chapter on Respiration.) CHAPTER X. 
RESPIRATION. 
Respiration involves inspiration and expiration. In inspira- 
tion about one-fifth of the amount of oxygen inhaled is absorbed 
by the body, while in expiration the carbonic acid gas—or, as more 
recently stated, carbon dioxide—is eliminated. 
The Trachea is a large tube formed of thick cartilaginous rings 
connected by elastic tissue. The rings serve to prevent the collapse 
of the tube (6, Fig. 21). Before entering the lungs the trachea 
bifurcates, forming two bronchi, the excretory ducts of the lungs. 
After entering the lungs each bronchus divides and subdivides into 
smaller tubes (bronchial tubes) until their diameter is less than 
one millimetre (0.039 inch); their further subdivisions are termed 
bronchioli, which terminate in the alveoli. ( Vide Fig. 22.) 
The Lungs (1, 2, Fig. 21) are the essential organs of respiration, 
the right lung being broader, but about an inch shorter than the 
left. This is because the diaphragm is higher (to accommodate the 
liver) on the right side than on the left. The weight of the right 
lung is about 22 ounces, while the left, which is more elongated in 
form (by reason of the heart lying partly inferior and anterior to 
it), weighs about 20 ounces. The tissue of the lung is of a pink- 
ish slate color, light, porous, and spongy, floating if placed in 
water, or crepitating if manipulated, on account of the presence of 
air in its alveoli. It is also highly elastic, which accounts for its 
collapse when removed from the closed cavity of the thorax, or 
wrhen air enters the pleural cavity. The parenchyma of the lung 
consists of minute lobules, blood-vessels, lymphatics, and nerve- 
fibrillse. The greater part of the lung is composed of lobules, each 
formed by a cluster of alveoli—also termed air-cells or air-vesicles— 
and held in position by minute, delicate, and very elastic tissue; 
indeed, each lobule is, in function, a lung in itself, so that if the 
major portion of the lobules are destroyed, as in tuberculosis, res- 
piration still goes on, until there are insufficient lobules left to 
adequately carry on the respiratory function; i. e., to supply the 
blood with oxygen and to remove the carbonic acid. A great many 102 
RESPIRATION. 
lobules are aggregated by connective tissue to form large lobes, two 
of which form the left lung and three the right. 
Physiologically, the respiratory organ (lung) consists essentially 
of moist and permeable membranes, with blood on one side and air 
on the other; yet 
the blood and air 
do not come in di- 
rect contact, but are 
absorbed and trans- 
ude through the 
membrane between. 
All the alveoli to- 
gether form in the 
adult lungs a respi- 
ratory surface about 
128 square metres in 
extent. The blood, 
therefore, in being 
distributed over so 
large a surface, is 
more completely ar- 
terialized. The ex- 
change of carbonic 
acid gas for oxygen 
is effected very rap- 
idly. Gases possess 
almost perfect free- 
dom of molecular 
motion. Owing to their unlimited tendency to flow, both liquids 
and gases are called fluids. It is natural for each substance in the 
mixture, if unobstructed, to flow from places where it exists in 
greater quantity to places where it is less abundant, and, according 
to two of the four laws of capillary action, the ascension and de- 
pression of a liquid not only varies with the nature of the sub- 
stance, but also inversely in conformity with the temperature. 
The Nerve-fibres of the lungs are derived from the anterior 
and posterior pulmonary plexuses, composed of filaments from the 
pneumogastric and sympathetic nerves. Some efferent respiratory 
nerve-fibres, though arising in the respiratory centre in the medulla 
oblongata, pass down the spinal cord and emerge from between the 
third, fourth, and fifth cervical vertebrae, collecting on each side of 
Fig. 21. 
Diagram of the Lungs. 
1, Right lung. 2, Left lung. 3, Pleura. 4, Pulmon- 
ary artery .5, Pulmonary vein. 6, Trachea. 7, Cri- 
coid and Thyroid cartilages. 103 
RESPIRATION. 
the cord into a nerve, called the phrenic, which supplies the half of 
the diaphragm on the corresponding side of the body. 
The Phrenic, or Diaphragmatic Nerve, arises from the 
union of the branches of the third, fourth, and fifth cervical pairs. 
It passes between the clavicle and subclavian artery, and descends 
by the pericardium to the diaphragm. If the phrenic nerve alone 
be divided outside of the spine, the channel for reflex impulses to 
the diaphragm being cut off, the latter is said to be paralyzed, and 
respiration is observable solely in the rising and falling of the ribs. 
A division or compression of the intercostal nerves only, paralyzes 
the intercostal muscles then respiratory movements are performed 
solely by the diaphragm. Division of the spinal cord above the 
third cervical vertebra interferes with the transmission of the reflex 
impulses through the phrenic and intercostal nerves, resulting in 
paralysis of the movements of the chest and abdomen, though the 
glottis, mouth, and nostrils may continue to act for a short time; 
the final efforts to respire are manifested in gasping and convulsive 
movements of the nostrils, for the reflex impulses from the medulla 
oblongata to these muscles still continues. If the medulla oblon- 
gata be injured, the power to reflex an impulse to breathe is at once 
taken away, and respiration ceases. 
That there are other nerve-fibres connected with the respiratory 
centre, besides those of the pneumogastric and phrenic, there can be 
no doubt. If, for instance, the nerve-fibres of the skin and chest are 
stimulated by an application of cold water, a gasping inspiration 
ensues. The nerves of the soles of the feet, or those of the skin of 
the sides of the body, if stimulated by tickling, causes laughter on 
account of a series of peculiar spasms of the diaphragm, abdominal, 
and facial muscles. A funny sight, the recollection of or present 
impression on hearing a humorous speech, causes similar spasms. 
The Respiratory Centre, or Vital Point, at which the 
rhythmic movements of the respiratory activities are regulated (re- 
flexly), is at the floor of the fourth ventricle in the medulla ob- 
longata, its afferent (sensory) nerve-fibres being those of the vagi, 
and the efferent (motor) those of the phrenic and intercostal nerves. 
Lymphatics.—The lung is well supplied with lymphatic cap- 
illaries, which take up not only the rudimentary matter from the 
lung tissue, but also the minute solid particles entering the alveoli 
with air, as noticed in the lymphatic-vessels of coal-miners. 
Blood of the Lungs.—The lungs are supplied with iwo kinds 
of blood, one for nutrition, the other for purification and stimulat- 104 
RESPIRATION. 
ing respiration. Consequently, the capillaries are from two sources: 
from the bronchial arteries and from the pulmonary. The bron- 
chial arteries (from the aorta) furnish blood to the parenchyma of 
the lungs for nutrition; this blood is returned through the bron- 
chial veins to the superior vena cava. The pulmonary arteries (from 
the heart) divide in the lungs into networks of capillaries, which 
run along on the inner surface of the alveoli. These capillaries 
unite to form larger venous branches, which again unite to form 
two large pulmonary veins from each lung, and discharge their 
contents into the left auricle of the heart. 
The Pulmonary Artery (4, Fig. 21; and E, Fig. 22) conveys 
the venous blood from the right ventricle of the heart to the lungs, 
where it divides into minute 
capillaries, which pass along 
the walls of the alveoli, adher- 
ing to them on the inner side 
by a small surface only, leaving 
the greater circumference of the 
vessels exposed to the air. This 
allows the blood in the capil- 
lary (C, D, Fig. 22) to come 
almost iii direct contact with 
the air in the alveolus (A). 
The delicate membrane of the 
pulmonary capillary through 
which osmosis, or interchange 
of the gases of the blood, takes 
place, is less than 1 -20,000th of 
an inch in thickness; the diameter of the capillary (C, D,) being 
from l-2000th to l-1500th of an inch. Each Alveolus (A) is a 
small recess at the termination of a bronchiolus (B), and is from 
l-200th to l-100th of an inch in diameter, and separated from the 
adjoining alveoli by thin walls or septa; consequently, they do not 
intercommunicate, but are held together by connective tissue. The 
diameter of the bronchiolus (B) is from l-500th to l-400th of an 
inch. It is estimated that the lungs of an adult contain about 
three millions of alveoli, the walls of which are lined with a single 
layer of squamous epithelial cells. The walls contain the blood 
and lymphatic capillary vessels and nerve-fibrillin. The network of 
capillary blood-vessels communicates from cell to cell, and the blood 
in the vessels remains exposed to the air in the alveolus (air-cell) 
Fig. 22. 
Diagram indicating Alveolus and 
Capillary Blood-vessel. 
A, Alveolus. B, Bronchiolus. C, 
Pulmonary artery portion of the capil- 
lary. D, Pulmonary vein portion of 
the capillary. E, Pulmonary artery. 
F, Pulmonary vein. K, K, K, K, Capil- 
laries of the adjoining alveoli. RESPIRATION. 
105 
about a second and a half to eliminate the carbonic acid, and 
absorb oxygen. At each inspiration, air enters the alveolus (A), 
through the bronchiolus (B); and the oxygen is absorbed by the 
haemoglobin in the capillary portion D. It cannot enter the por- 
tion indicated by the letter C, as this portion is filled with venous 
blood saturated with carbonic acid, the gas of which is just escap- 
ing. The carbonic acid issues from the blood at C, and the blood 
on arriving at D is capable of absorbing oxygen. That the oxygen 
is absorbed at D, but not the carbonic acid gas, although inter- 
mixed more or less in the alveolus A, may be explained in two 
ways: 1. The powerful attraction of the haemoglobin, with its iron, 
for oxygen, and its want of attraction for carbonic acid gas. 2. The 
heated carbonic acid gas has a powerful expansive force towards a 
free surface, especially towards the colder gas (the atmosphere) ex- 
ternally. This explains why respiration in an atmosphere of higher 
temperature than that of the blood is more difficult and hurried. 
In this case, the carbonic acid gas is imperfectly carried off from 
the lungs, and the skin assumes greater activity (sweating) to com- 
pensate for this deficiency. The lungs manifest a wise arrangement 
in the conveyance of venous blood by an artery (pulmonary), as 
an arterial vessel only can withstand the pressure of the ventricle 
of the heart; so, also, in the conveyance of arterial blood by veins 
(pulmonary), which easily relieve the lungs of their blood. 
The Four Pulmonary Veins return the aerated blood (arte- 
rial) to the left auricle of the heart; consequently, it is owing to the 
process of respiration that the dark venous blood is changed into a 
bright arterial red. This blood, in passing through the capillary 
vessels of the body, supplies the tissues with oxygen and with nu- 
tritive substances, and during this process gradually becomes recon- 
verted into venous blood and returned to the heart, which sends it 
through the pulmonary artery to the lungs, in order to again receive a 
fresh supply of oxygen. The local contact of the gases (air and carbo- 
nic acid gas) and the organic matter in the blood in passing through 
the lungs furnishes the stimulus for continual activity of these organs. 
The carbonic acid and the organic matter are, no doubt, the irritat- 
ing substances—the oxygen the alleviating (satisfying) element. 
The respiratory centre in the medulla oblongata acts by reflex; just 
as do all nervous centres by which impulses on organs are reflected. 
Each centre is connected, either directly or indirectly, with the organ 
by afferent (sensory) and efferent (motor) nerve-fibres. This is the 
best proof that the sensation of any organ lies primarily in the organ 106 
RESPIRATION. 
itself, and notin the nervous reflex centre. Were its seat in the lat- 
ter, then the afferent fibres would be superfluous, and the efferent 
sufficient. Consequently, the stimulation and sensation for respira- 
tion lie in the lungs, and not in the so-called vital spot of the medulla 
oblongata, this being simply the spot, or centre, where respiratory 
reflex actions are accomplished. 
The Haemoglobin of blood-corpuscles is formed completely in 
the capillaries of the lungs. It is allied to the albuminoids (pro- 
teids), and forms the chief constituent of the red corpuscles. It con- 
tains, in addition to carbon, hydrogen, oxygen, nitrogen, and sulphur, 
about 4 parts of iron in 1000 of blood. The absorption of oxygen in 
the lungs depends mainly on the molecular attraction inherent in the 
molecules of the hsemoglobin. When iron is deficient in the blood, 
the htemoglobin is defectively developed, and the supply of oxygen 
and nutritive substances to healthy tissue-changes in the brain, 
nerves, muscles, etc., becomes lessened; hence, the defective vitality, 
general or local, during such deficiency. When arterial blood in the 
capillary circulation comes in contact with the tissues, the red blood- 
corpuscles furnish them with nourishment by giving up the greater 
part of their oxygen, iron, haemoglobin, and the potassium salts. 
The red corpuscles become anaemic when parting with these constitu- 
ents. Some of the corpuscles then become disorganized and broken 
up; though the greater number return to the heart and lungs for re- 
cuperation, or for another supply of the above-mentioned constitu- 
ents. They possess, however, no properties in common with those of 
the carbonic acid, except that both (carbonic acid and oxygen) pass 
through the same channels. The haemoglobin of the corpuscles en- 
tering the liver furnishes one of the basic constituents essential to 
the secretion of bile. 
The Haematin of the blood is of a dark-brown color, and results 
from the decomposition of haemoglobin. The term “haematin” is 
derived from the Greek word meaning blood. 
The movements of the lungs, glottis, chest, and abdomen corre- 
spond with each other in point of time and intensity, so that the 
same reflex by nervous centre influence that expands the chest for 
inhalation opens the glottis to admit the air. Only about l-5th of 
the air in the lungs is renewed at each inspiration. The number of 
respirations in the adult averages about 18 per minute; in youth, 
20; in childhood, 26; in infancy, 40. During inspiration a rustling 
sound, termed vesicular murmur (crepitus), is produced by the 
alveoli, and is more distinct in children than in adults. RESPIRATION. 
107 
Like pulsation, respiration is involuntary and purely through 
reflex. By the force of the will we may partially change or arrest 
the rhythm of respiration, though only temporarily, or until the 
intensified stimulation on the lungs, caused by the accumulation of 
carbonic acid elements in the capillaries of the lungs, forces respira- 
tion. This is wdiy a person can remain under water for a short time 
only. 
The expansive force of the lungs depending on the thoracic exten- 
sion, they collapse with the thoracic contraction. During inspira- 
tion the diaphragm descends (contracts) and the intercostal mus- 
cles raise the ribs and sternum, enlarging thereby the cavity of the 
chest. In children and in the adult male the respiratory move- 
ments are most noticeable in the abdomen, but in the adult female 
the upper part of the chest is put in more active motion. During 
the inflation of the lungs with air (inspiration) the diaphragm con- 
tracts, while during expiration this action is reversed. In disease 
or injury of the lower cervical or upper dorsal region of the spinal 
cord, the transmission of the reflex efferent impulse being interfered 
with, the intercostal muscles are paralyzed and the thoracic respir- 
atory movements arrested; then the movements of the abdominal 
respiratory muscles will be increased. In peritonitis, or other forms 
of abdominal inflammation, the movements of the abdominal mus- 
cles and the diaphragm are restrained on account of the pain pres- 
ent, and the thoracic respiratory movements are increased. The 
extension and distension of the many organs during inspiration is 
the principal organic force which, in reaction, produces expiration. 
It may be here noted that the contraction of the intercostal muscles 
is not inspiratory, but expiratory—a function opposing that of the 
diaphragm; i. e., the contraction of the latter favors inspiration; of 
the former, expiration. An adult requires about 350 cubic feet of 
air per day. When the inhaled air contains less than 10 per cent 
of oxygen, asphyxia and then death ensue. In such cases the air 
is already more or less saturated with carbonic acid gas, so that the 
power of its elimination from the lungs is diminishe 1 and the inspi- 
ratory stimulus increased; but, as little or no oxygen enters, the in- 
creased stimulation is not relieved (satisfied), and the cells of the 
alveoli of the lungs become so exhausted that little or no stimulus 
is forwarded to the reflex centre of the medulla oblongata, and no 
reflex impulse is conveyed to the respiratory muscles for expiratory 
movements; and sooner or later not only the lungs, but all the 
muscles of the body are affected by the carbonic acid stimulation. 108 
RESPIRATION. 
This results in greater or less convulsive movements, succeeded by 
tranquillity. This condition is due to exhaustion (asphyxia). 
The changes effected in inspired and expired air are as follows: 
Composition of inspired air 
Nitrogen 79.02 by volume. 
Oxygen 20.94 “ “ 
Carbonic acid 04 “ “ 
100.00 
Composition of expired air 
Nitrogen 78.25 by volume. 
Oxygen 16.25 “ “ 
Carbonic acid 5.50 “ “ 
iUO.OO 
Should air enter the pleural cavity by an opening through the skin 
and thoracic wall, or from within the lung or respiratory passages, 
the lung collapses (pneumothorax), and is no longer capable of dis- 
tension. If this happens to both lung cavities, death results. In 
case, therefore, it becomes necessary to open the pleural cavity care 
must be taken that no air enters and that the external opening be 
well protected until healed. Some water passes from the blood by 
respiration and perspiration, the kidneys not being able to elimin- 
ate all that is required to be removed. From the lungs about 10 to 
18 ounces of watery vapor are exhaled in 24 hours, being increased 
or diminished according to the temperature and moisture of the 
atmosphere and body. A person with a dry and hot skin respires 
very frequently. When, however, thorough perspiration takes place, 
respiration becomes less frequent. In the canine family the tongue 
is often protruded, and respiration doubled and trebled in frequency 
by the increased stimulation of the carbonic acid caused by increased 
muscular activity or by exposure to external heat. The dog’s integ- 
ument contains but few perspiratory glands, and even these few 
empty into hair follicles, instead of discharging directly on the 
surface of the skin. 
Besides carbonic acid gas and water, a small quantity of ammonia 
and organic matter is emitted by the lungs and skin, which gives a 
faint odor to the breath and perspiration; this is very noticeable in 
a crowded and confined space, and causes the atmosphere to become 
oppressive. The amount of ammonia and of organic matter ex- 
haled has not yet been definitely ascertained. 
Carbonic Acid Elements exist in combination with bases in 
blood-plasma, teeth, and bones. The carbonic acid gas, as such, 
does not exist in the blood in the form as excreted any more than 
fibrin, urine, tears, perspiration exist as such in the blood, but the 
gas is completely formed (secreted), as the urine, tears, and perspi- RESPIRATION. 
109 
ration are, at the organ of exit; i. e., said gas is secreted from the 
material existing in venous blood, by the cells of the capillaries in 
the walls of the alveoli of the lungs, sudoriparous ducts of the skin, 
and uriniferous tubules of the kidneys. The cells of organs have 
their own way of doing things, and very likely will keep their secret. 
No one has ever been able to separate or produce by art or science 
a genuine normal urine, tears, perspiration, gastric juice, or any 
other secretion from blood, as the living cells of the body do. As 
well try to separate or produce the genuine normal fragrance of a 
growing plant or flower; the product may be ever so deceiving, but 
it is not genuine. Carbonic acid has the formula C 02; i. e., one 
atom of carbon and two atoms of oxygen; yet it cannot be denied 
that when this gas issues from the living animal body it also con- 
tains ammonia, nitrogen, and organic matter. 
The alkalinity of the blood, especially the carbonate salts, com- 
ing in contact with the acidity (a form of lactic acid) of the tissues, 
may effect the combination of atoms essential to the formation of car- 
bonic acid, but the formation of gas is not complete until the material 
has passed through the cells of the organs of exit. An aqueous solu- 
tion of carbonic acid reddens blue litmus paper. It may be said 
that whenever alkali and acid, with moisture, come together, carbonic 
acid gas immediately results; but in no instance can it be shown 
that the action of chemical elements and the results of chemical 
reactions are the same immediately within the tissues, including the 
blood of the living animal economy, as when mixed chemically 
pure and outside of the body. The chemical constituents of the tis- 
sues are all known, and yet we are at a loss to explain on chemical 
or physical grounds that final transformation of food by which it 
becomes a part of the living animal body; neither can we, by chem- 
ically combining the fifteen elements which are found in the human 
body, produce an organic vital being. This will be rendered clear, if 
we but consider that a thing cannot give what it has not. A com- 
bination of any number of dead inorganic elements can never pro- 
duce a vital organized being, according to the philosophical prin- 
ciple, that the effect cannot be above or greater than its cause. 
Vitality is above chemism and superior to all physical and mechan- 
ical energy. The task of science is to strive after truth, without hav- 
ing any secondary object in view. No doubt chemism may explain 
the physical activity of organs; but it cannot solve the problem of 
animal vitality any more than it can the merely physical or me- 
chanical forces seen in nature about us. 110 
RESPIRATION. 
In every bodily action food is required to supply the wasted ener- 
gy. This food is not only the matter taken into the system and 
assimilated, but anything which goes to supply the want of any 
particular organ or tissue; be it an acid, alkali, or salt, etc. Thus 
an inactive animal body, suddenly becoming active, requires an 
increased diet. 
It may be noticed that the results of experiments on mamma- 
lians are not mentioned here. This is because they are so conflict- 
ing; one claiming that the amount of carbonic acid exhaled is in- 
creased during cold weather—i. e., in December, January, and Febru- 
ary—and decreased in June, July, and August, respectively; another, 
that it is greater in warm weather; or in a moist than in a dry 
atmosphere, or vice versa. All experiments have been conducted 
to ascertain the quantity, quality, and possible action of said gas 
within the living body, though when outside of its environment— 
even when taken direct from the alveoli of the lungs; but it cannot 
be true that this external gas is the same as the materials when in 
the venous blood, and for the reasons already mentioned. If the 
air-passages be closed completely the respiratory efforts become 
deep, labored, energetic, and rapid, and the circulation increased 
(asphyxia). This also indicates that the primary stimulus for 
inspiration and circulation is the carbonic acid elements, within 
the blood, on the lungs and heart; and not the oxygen. The use of 
oxygen is, of course, to satisfy or moderate overstimulation. The 
cause of the revolution of a rapidly turning wheel is the power 
that turns it, and not the brake that modifies the motion. The 
respiratory and circulatory reflex centres of the medulla oblongata 
are very close neighbors—possibly one; so that a stimulus from the 
mind, or stimulation from the carbonic acid in the blood on the 
heart and lungs, is reflected by the respiratory or circulatory centre 
through efferent impulses on the heart and lungs, correlating the 
activity of these organs. Cold-blooded animals exhale very little 
carbonic acid gas, comparatively, indicating that their tissue waste 
is not so rapid and the material for carbonic acid gas in their cir- 
culating fluid is less; therefore, the primary stimuli for circulation 
and respiration are not so marked as in the warm-blooded animals. 
Plants absorb carbonic acid gas by their leaves, peripheral cells, 
and roots. The leaves act as respiratory organs, absorbing carbonic 
acid gas (as may be easily proved by the celebrated experiment of 
Priestly), and giving off oxygen, which, in the plants, is derived by 
transformation of water, carbonic acid gas, and of various salts. RESPIRATION. 
The stimulus on the lungs for inspiration is the carbonic acid 
elements acting on the epithelial cells in the walls of the alvioli, 
and the stimulus for expiration is the satisfying effect of the atmos- 
pheric oxygen on said cells. An excess of carbonic acid in the sys- 
tem causes depression of spirits. This may be relieved by tea or 
coffee, which produces an increased elimination of this acid, at least 
greater than that supplied by the food. Carbonic acid eliminated 
from the animal organism, and again introduced into the body, acts 
as a poison, similar to that produced by chemicals and introduced 
in the gaseous form alone; while the chemical gas moderately intro- 
duced with water (soda water) into the stomach diminishes thirst, 
acts as a diuretic, lessens morbid heat and irritability of the stom- 
ach, and is slightly anti-emetic. Respiration in an atmosphere 
deficient in oxygen becomes hurried from overstimulation of the car- 
bonic acid, and, if continued, respiration may soon cease altogether. 
It may be noticed here that this theory of external organic 
sensation contravenes the teaching of the present day touching 
the primary cause of the normal activity of organs in continuous 
action, such as the lungs, heart, capillaries, kidneys, and skin. (See 
Respiratory Activity of the Lungs, and Pulsative Activity of the 
Heart.) The venous blood-plasma being saturated with the ele- 
ments of carbonic acid, and the ready-formed gas issuing from the 
arterial portion of the pulmonary capillary (C, Fig. 22), the oxy- 
gen has no chance to enter there, though it does enter at the venous 
portion of the pulmonary capillary (D). The epithelial cells of 
these vessels, by absorbing and giving off gases, dilate and contract 
in the walls of the alveoli, especially in the middle portion of the 
capillaries, producing peristaltic action of said walls; consequently, 
it aids the movements of the blood within the capillaries, the car- 
bonic acid elements being loosely contained in the blood-plasma. 
(Vide Capillary Action in chapter on Circulation.) The blood- 
corpuscles have little or no attraction for said elements, or already 
formed gas, but a most powerful attraction for molecules of oxygen 
gas. The oxygen itself has decided magnetic properties (paramag- 
netic), like those of iron; but carbonic acid, water, and nitrogen 
have decidedly repellent properties (diamagnetic). This offers an 
explanation as to how both gases, though more or less mixed in the 
cavities of the alveoli, pass—the one inward, the other outward (A, 
Fig. 22). When two gases are placed in contact it is impossible to 
prevent them from mixing, for every gas diffuses into every other. 
They easily separate, however, and a lighter may rest upon a heavier 112 
RESPIRATION. 
when one is of higher temperature than the other, as oil rests 
upon water. The passage of both gases, through the activity of the 
epithelial cells in the membrane of the capillary, is assisted by the 
law of diffusion called osmose—the oxygen being favored by the 
powerful attraction of the molecules and the incessant motion of 
the red blood-corpuscles, the carbonic gas escaping by the expansive 
force of heat. The pressure of a given body of gas, the volume 
of which is kept constant, is in proportion to its absolute tempera- 
ture. In the lungs the formation and pressure of the carbonic 
acid gas (to escape) are also assisted by the pressure of the blood in 
the pulmonary artery. The activity of the chest wall, respiratory 
muscles, diaphragm, and glottis is through reflex, the lungs being 
stimulated by the carbonic acid for expansion, by oxygen for satis- 
faction (contraction), each stimulus forwarding an impulse through 
afferent nerve-fibres of the vagi, respectively, to the respiratory cen- 
tre in the medulla oblongata, where said impulses are reflected and 
forwarded by efferent fibres through the phrenic and intercostal 
nerves, calling into activity all respiratory organs correspondingly, 
just as the stimulation of normal food on the stomach prompts the 
emptying of the gall-bladder. An abnormally high temperature of 
the carbonic acid elements in the blood stimulates the epithelial 
cells in the walls of the alveoli of the lungs and mucous membrane 
of the cavities of the heart to increased activity, and consequently 
to hurried respiration and pulsation. This explains why respiration 
and pulsation proceed normally in unison. 
The absorption of oxygen and the elimination of carbonic acid 
gas are also effected, more or less, by the activity of the cells of the 
skin. Covering the entire cuticle with an impermeable substance, 
such as glue or varnish, causes death. It is like closing the prin- 
cipal air channels, mouth and nose, though the process is slower. 
This also indicates that it is the local stimulation by the carbonic 
acid from within, and oxygen from without, on the epithelial cells 
in the walls of the capillaries of the ducts of the sudoriparous 
glands that excites activity. Some of the acid gas is also discharged 
with the urine. That eliminated by the skin and urine amounts 
to about four and a half per cent of the amount simultaneously 
exhaled by the lungs. This furnishes another evidence that the 
continuous stimulus for respiration is the carbonic acid within the 
blood acting on the lungs; for every organ by which this gas is 
eliminated is one of incessant activity, as the lung, skin, and kid- 
ney. We notice that the elements of carbonic acid, while normally RESPIRATION. 
113 
in the system, are of the most vital importance. That the ready 
formed (exhaled) carbonic acid gas, as such, exists already under 
the same condition in the venous blood, must be very doubtful, for 
when it issues from the body and is injected again into the venous 
blood it kills the animal. Again, that said gas cannot exist in the 
blood may be illustrated by filling a bottle entirely full of water 
and introducing a suitable capsule filled with a small quantity of 
tartaric acid and bi-carbonate of soda. Close the bottle with the 
palm of the hand, or otherwise, so that it remains absolutely full. 
As long as the capsule is not dissolved, no action is noticeable in 
the bottle, but as soon as it dissolves and the atoms of acid and 
soda become active the bottle bursts, there being no space for the 
carbonic acid gas which is evolved. Now, if carbonic acid gas in 
the animal tissues or venous blood existed in the same form as that 
evolved by the organs of exit, the veins would burst, especially un- 
der the pressure of an abnormal increase of this gas; but the fact 
is that they do not even dilate. Artificial respiratory excitants 
increase the exhalation; non-excitants diminish it. Albumen, as 
food, is one of the least respiratory excitants. Temporary cessa- 
tion of the menses, due to pregnancy or otherwise, increases the 
exhalation of carbonic acid; so does muscular activity. The car- 
bonic acid gas exhalation is diminished during sleep. Heat being 
the most general molecular stimulus, a warm atmosphere increases 
the activity of the cells of the skin, just as a sudorific remedy 
when taken into the body produces increased perspiration, more 
carbonic acid gas and heat is given off, and the temperature of the 
system lowered. Any remedy stimulating the cells of the urinif- 
erous tubules and Bowman’s capsules of the Malpighian bodies of 
the kidneys, acts similarly to increased secretion of the solids of 
the urine, just as the remedy stimulating the epithelial cells of the 
walls of the arterial capillaries within said bodies (possibly assisted 
by the arterial blood pressure) increases the secretion of the watery 
portion of the urine. Since irritability (sensitiveness) of an organ 
or tissue is the property of becoming excited to activity when acted 
upon by the appropriate stimulus, so force causes a body to move 
as well as to come to rest. The channels of the blood-circulation 
serve two opposite purposes in taking in and giving off the elements 
of oxygen and carbonic acid. The oxygen enters the body through 
the lungs, skin, and alimentary canal; the carbonic acid leaves it 
by expiration, perspiration, urine, and the feces. 114 
RESPIRATION. 
Carbonic acid gas is about one and one-half times heavier than 
air at the same temperature; but when heated above that of the 
surrounding air—as when generated by fire, or when escaping with 
the warm breath of animals—it is lighter, and, consequently, rises. 
The human body is composed of about fifteen chemical elements; 
and, coming in contact with each other in the vital economy, their 
antagonism and combination produce heat. Some of these elements, 
such as water and sodium chloride, do not undergo much alteration; 
others, again, are transformed into new substances which assist in 
reconstruction, while some favor destruction; the latter producing 
acidity in the tissues as well as the generation of heat, similar to 
that produced by muscular activity. Chemistry leads to the deduc- 
tion that it is the action of oxygen on carbon which produces oxida- 
tion in the vital animal economy, similar to the action of the oxygen 
of the air in combining with the various fuels, such as wood, coal, 
oils, and illuminating gas, giving rise to what we call combustion, 
by which heat is generated. Any increased quantity of fuel and 
oxygen increases the heat of a furnace, or heat generator; but how 
can one satisfactorily explain, chemically, the rise of temperature 
as being oxidation in the living animal economy, in typhoid or any 
other fever, when no increased quantity of oxygen and carbonaceous 
food is furnished? All normal organic destructive tissue-changes 
produce acidity, which, coming in contact with the alkaline fluid 
(blood), changes the carbonic bases, the product stimulating 
the lungs, heart, and several other organs, such as the skin and 
kidneys, to continual normal activity, when the ready-formed gas 
issues through the lungs, skin, and kidneys; but when the molecu- 
lar activity is increased, as in certain pathological conditions, then 
the carbonic acid products are increased, and in return stimulate 
all the cells of the tissues to abnormally increased activity, result- 
ing in an elevated temperature, which may be lowered by opening 
all cutaneous vents (perspiration) and allowing the acid elements and 
gas to escape. This is the true physiological process in the lowering 
of temperature. All others, such as cold or sedatives, are artificial. 
In the artificial process the cells and organs become more or less 
paralyzed and their activity decreased. It may be said in opposition: 
It is not the carbonic acid elimination, but the elimination of heat, 
which reduces the temperature. If the latter were true, the tem- 
perature would rise again immediately when the elimination stops. 
This it does not do. To every action there is a reaction, so that 
when the cells in the tissues become anaemic, lamed (paralyzed) RESPIRATION. 
115 
from overwork, the production of carbonic acid ceases correspond- 
ingly, similar to the manner in which excessive muscular and 
excessive mental action lessens its formation, while moderate exer- 
cise of either increases it. Here we may find the cause of the 
periodical rise of temperature, be it from alimentation, periodical 
formation or ripening of a poison within the system during a patho- 
logical condition, periodical activity of saprophytes or pathogenytes, 
or from other causes stimulating the cells to increased activity, 
increasing the evolution of carbonic acid, and, as a consequence, 
causing a periodical rise of temperature. 
Now, in the foregoing there are sufficient grounds for asserting 
that the terms “oxidation,” “combustion,” or “a burning up,” are 
ill applied when used in reference to the evolution of heat in the 
vital economy. Such terms tend only to confuse when referring 
to the vital action within the organism. The metabolic processes of 
cells and tissues (this includes anabolic and katabolic processes), 
taken as a whole, may resemble combustion, because oxygen and 
carbon are taken in and carbonic acid gas is given off; but (to illus- 
trate) no one would call the mixing of soda and vegetable acid in 
water, even though carbonic acid gas be evolved, oxidation. Again, 
no one would call the mixing of equal parts of alcohol and water, 
although heat be generated, oxidation. In no instance in nature 
is the combustion of a substance containing three-fourths of its own 
quantity of water possible, whereas, the blood and most of the tissues 
do contain this amount. The terms “oxidation” and “combustion” 
applied to the vital economy are therefore improper. 
Again, too much stress is laid on the importance of oxygen in 
the vital economy. It is true that without it vital processes could 
not go on; but the same thing applies to many other elements, 
such as carbon, hydrogen, and sulphur. An abnormal amount of 
pure oxygen introduced into the system will paralyze, by oversatis- 
fying the respiratory organs, as completely as carbonic acid will 
paralyze them by overstimulation. Oxygen generally receives the 
credit of being the sole cause of the chemico-vital actions; but we 
find that if it were not for the carbonic acid in the animal econo- 
my, respiration and circulation would cease. We also find that 
the exhaled gas is not fully covered by the term “carbonic acid,” 
or C02; consequently, the extent of action of the elements of said 
acid, while yet in the blood, must be of far-reaching importance in 
regard to stimulation, in fact more so than is generally believed; 
i. c., of such as already above indicated. 116 
RESPIRATION. 
Nitrogen, combined with hydrogen, oxygen, carbon, and sulphur 
forms important compounds (proteids) of the secreted solids and 
fluids within the animal body. 
Physiologically, sulphur exists in all albuminous substances; 
and, as no animal organic life can exist without albumen, the 
question arises, Has sulphur a physiological importance? This 
question is introduced here simply with reference to oxygen, to 
show that other elements are fully as necessary as oxygen is to ani- 
mal vitality. Sulphur is not an accidental addition, as it is con- 
stantly present and found in all animal tissues. These are built 
up principally from albuminous substances, all of which contain 
sulphur, no animal organism or tissue existing without it. It is 
also necessary for the elementary activity of cell-life, which it 
increases by assisting the chemical combinations of molecules of 
hydrogen, oxygen, nitrogen, and carbon; and, consequently, of 
albumen, which is thus dissolved, changed, and made capable 
of forming a part of the tissues. In comparison, just as the iron 
in haemoglobin is necessary to enable the haemoglobin to take up 
oxygen in the lungs, and then be carried to the tissues, so is sul- 
phur primarily necessary for the continuation and transformation 
of albumen into tissues. 
In the male, the production of carbonic acid increases from the 
age of seven to twenty-five, but beyond forty-two it gradually 
decreases. As old age approaches it may even not exceed the 
amount produced at the age of ten. In the female, it increases 
from the age of seven until menstruation, the production of car- 
bonic acid then remaining stationary up to the cessation of the 
menses, when it decreases, as in the male. Males from fifteen to 
forty-two exhale nearly twice as much carbonic acid gas as females, 
and a child twice as much as an adult, if their disparity in weight 
be duly considered. 
Certain animals that breathe by lungs, as ducks and frogs, are 
nevertheless able to remain under water for a considerable time, as 
their thin, moist, and flexible integument then performs the func- 
tion of respiration. Their skin is not covered with dry cuticle, 
and while under water the lungs are inactive, but respiration goes 
on; i. e., the exhalation of carbonic acid gas and absorption of oxy- 
gen takes place through the skin. 
Dyspnoea (difficult breathing) may be caused by lung disease 
preventing sufficient respiratory movements, partial closure of 
respiratory passages, insufficiency of red blood-corpuscles, affec- RESPIRATION. 
117 
tions of the respiratory muscles, nerves, or centre in the medulla 
oblongata, deficient circulation in the lungs from heart affections, 
especially mitral valve lesions, dropsy, uraemic poisoning, or from 
fever heat, producing excessive carbonic acid stimulation on the 
heart and lungs. 
In order to promote respiration in the newly born infant, or to 
overcome asphyxia from drowning or from other causes, stimula- 
tion of the nerves which are distributed to the face or chest may 
cause powerful reflex action by the centres of the pneumogastric, 
spinal accessory, phrenic, and intercostal nerves. This fact is 
proven by the sudden application of cold water to the face or chest, 
or by alternate applications of hot and cold water. ( Vide Artificial 
Respiraton in chapter on Miscellaneous.) CHAPTER XI. 
TEMPERATURE. 
In the human body a standard temperature is maintained, not- 
withstanding atmospheric variations. Vital or animal heat is 
produced by the changes of chemical combinations of elements, 
including the activity of the nutritive processes and disintegration 
that take place separately in each organ and tissue; therefore, the 
temperature varies in each organ and tissue: — 
1. The more active the organ the more blood passes through it; 
consequently, the higher the temperature the more active its tissue 
changes. 
2. Protoplasm, in the process of its activity, evolves heat. The 
more active, especially when the process of disintegration surpasses 
that of construction, the higher the temperature. 
3. The liver and other glandular organs are great heat-produc- 
ing centres. 
4. Mental and muscular activity increases heat. 
5. The amount of heat abstracted from the surface of the body 
depends on the extent exposed and atmospheric influences. 
Heat is a sensible quality of bodies accompanied by motion. It 
expands all kinds of matter, whether solid, liquid, or gaseous. Heat 
and energy are so related that a definite quantity of one may be 
always changed into a definite quantity of the other; for, accord- 
ing to the doctrine of the conservation of energy, when one form 
disappears another or others take its place, i. e., the correlation of 
energy is such that one kind can be changed into another, and the 
sums total are equivalents. Molecules and their atoms possess 
potential energy, which becomes kinetic during chemical action; 
i. e., the clashing together of atoms, in consequence of affinity, gen- 
erates heat. Such is, in part, an explanation of the origin not 
only of animal heat, but also of muscular motion and organic 
activity. In animal organic activity, the vital principle also 
maintains its share. Heat is required for the normal molecu- 
lar action of all vital activities, since heat causes the molecules 
to move more rapidly and to a farther extent in their spaces, 
usually pushing their neighbors away a very little, and the size of 119 
TEMPERATURE. 
the body increases. Hence, heat will diffuse itself into surrounding 
tissues, and thus tends to equalize the temperature; always passing 
from a warmer to a colder section. 
A liquid will dissolve a solid only when the adhesion between 
them is greater than the cohesion in the solid; and, as heat general- 
ly weakens cohesion more than it does adhesion, therefore an ab- 
normally high temperature of the liquid blood dissolves the more 
solid tissues more rapidly and in greater quantity than when at 
a normal temperature. Heat is always generated in consequence 
of motion; so that from any irritation, molecular or mechanical 
activity, the temperature is raised, and the effect is expansion and 
change of matter. The temperature of the living body is the same 
in summer and winter, its regular standard being maintained by the 
blood-circulation and by radiation of heat, the equalizing or modera- 
ting power lying in respiration by lungs and cutaneous perspiration. 
Absolute rest does not exist in nature, consequently not in the 
human body. Motion and rest, therefore, are only relative terms. 
By food man appropriates the latent energies of the animal and 
vegetable substances, which are converted into energy—atomic and 
molecular motion, heat, cell-growth, tissue changes, circulatory, 
respiratory, secretorjq and muscular activity. 
The deeper tissues of the body are warmer than the more super- 
ficial, due not only to the increased vital action and consequent 
changes taking place in those structures, but also to their greater 
protection, wdiile the more external parts are constantly losing heat. 
Immediately after a full meal the heat of the body is reduced, but 
as soon as digestion commences and absorption takes place its tem- 
perature rises. It is diminished by abstinence from food and ex- 
posure to cold. The division of a sympathetic nerve causes a re- 
laxation of the blood-vessels to which it is distributed, destroying 
the connection for reflex action, so that the blood pressure relaxes 
(dilates) the vessels, thereby increasing the quantity of blood in 
the part affected, which at first increases the temperature; but sub- 
sequent loss of nutrition of the part follows. The temperature of 
venous blood varies in proportion to the activity of each particular 
organ or tissue, while that of arterial blood is almost uniform, ex- 
cept in the arterial capillaries of the lungs and skin, where it is 
cooled by exposure to a cooler atmosphere, the body thereby con- 
stantly losing heat by radiation and conduction; therefore, this 
deficiency must be continuously overcome by newly formed heat in 
its interior. Wherever a combination of atoms of substances that 120 
TEMPERATURE. 
have an attraction for each other takes place, heat is evolved, illus- 
trated by mixing water three-fourths and sulphuric acid one-fourth, 
by which heat is instantly evolved. The chemical potential energy 
of the atoms is converted during collision and recombination into 
kinetic energy; i. e., into molecular motion, so that any change of 
vis viva (living energy) in the system corresponds to an equal 
amount of exertion gained or lost by the attractions of the par- 
ticles on each other. Through the medium of the blood the mate- 
rials necessary tor the renewal of the normal quantity of caloric 
are supplied—supplying heat also where lost by exposure. The 
temperature of the blood in the left auricle of the heart is from 1 
to 6 per cent of a degree lower than in the right, on account of hav- 
ing been cooled by contact with the atmosphere in its passage 
through the lungs. In the hepatic veins it attains the highest tem- 
perature of the body on account of having passed twice through 
functional activities, such as the capillary circulation of the spleen, 
stomach, intestinal wall, and the liver; while in the blood of the pe- 
ripheral capillaries it is the lowest. The average mean temperature of 
the venous blood is higher than that of any other tissue. When 
the internal temperature rises to from 107° to 110° Fahrenheit (41.5° 
to 43° Centigrade) it .generally proves fatal, though the individual 
can live in an atmosphere of from 118° to 125° F. (47° to 50.5° C.). 
Heat is measured in calorics; temperature, in degrees. A caloric is 
the quantity of heat required to raise the temperature of 1 kilo- 
gram of water from 0° to 1° Centigrade. The term temperature has 
no reference to quantity of heat, for if a pint be taken from a 
gallon of boiling water, the temperature of the former is the same 
as the latter, although having only one-eighth the quantity. 
The normal temperature in an adult is about 98.5° F. or 37.25° C.; 
but it is normally highest between 4 and 5 p. m. and lowest be- 
tween 4 and 5 a. m. At birth it is about one or two degrees higher 
than between birth and 50 years, but at extreme old age it rises 
again. 
Fig. 23. 
Diagram of Thermometer according to Fahrenheit. 
To change Fahrenheit degrees into Centigrade, or vice versa:—From 
the given F. subtract 24, and half of the remainder will be the TEMPERATURE. 
121 
corresponding degree C.; or, to change Centigrade into Fahrenheit, 
double the given C. and add 24; the sum will be the degree F. 
The normal temperature of the body may be maintained from 
two sources when exposed to cold; viz., ample supply of food, and 
muscular activity. The ill fed cannot resist cold. A persistent 
abnormality indicates some morbid action in the economy, though 
a fatal disease may ex:st even with a normal temperature, as is oft- 
en the case in chronic Bright’s disease. 
Temperature is intimately related to the functions of vitality. 
If it be increased or diminished by a few degrees, a corresponding 
interference with the perfect mechanism of the various organs oc- 
curs, so that their relative activity may either be augmented or ar- 
rested. The phenomena of vital activities, such as nutrition, 
growth, and reproduction, are possible only within certain limits of 
temperature; for as soon as it approaches the limit below or above 
the normal, constructive vitality ceases. These limits, or extremes, 
of internal human temperature range between 90° and 110° F.—i. e., 
about 20 degrees; but it is difficult to give a general extreme in any 
special disease, as the fatal point depends on the pathological con- 
dition of the system at the time. If an abnormally high temper- 
ature is not checked, either the coagulation of the albuminoids and 
amyloids of the protoplasm, or of the proteids of the tissues, or of 
both, takes place; there is then an increased change or decomposi- 
tion of the tissues and secreted fluids, which results in an arrest of 
nutrition and vitality, and causes death. 
Generally, temperature rises or falls in unison with the rise and fall 
of the pulse. For every degree above 100° F. the pulse rises ten pulsa- 
tions per minute. It may be several degrees above or below the normal 
for some days before sickness is experienced; consequently, the 
importance of an early investigation of internal temperature is ap- 
parent, as it often furnishes the clue to correct diagnosis of a disease 
which cannot otherwise be surmized, and is an early guide for treat- 
ment. The different kinds of food and stimulants have their re- 
spective influences on the temperature; consequently, it is important 
to make more than one observation, and at different times. It is 
also a sure detective in certain cases of feigned disease; or if an in- 
creased pulse is due to fever or to anaemia; or if abnormal sweating 
is the result of external heat, activity, disease, or exhaustion. If 
from disease, it will be preceded by elevated temperature. 
In regard to internal temperature the external indications cannot 
be relied upon, as the integument may feel cool to the touch 122 
TEMPERATURE. 
though the thermometer may register 105° or more, as in some low 
forms of disease; consequently, external indications simply are 
not a means by which we can acquire any definite idea of the tem- 
perature of the body. Illustration: if a piece of flannel and a piece 
of iron are left in a room for some time, each will be of the temper- 
ature of the room; yet to the touch the flannel would be pronounced 
warm and the iron cold. The temperature of the body may be 
taken by placing the thermometer under the arm-pit or the tongue, 
but it is most accurately indicated by placing it for 8 or 10 minutes 
in the rectum or vagina. No cause except disease or old age changes 
the temperature more than 1.5° F. the normal. The excessive 
waste of tissues in old age often causes the temperature of the body 
to rise two degrees above normal without exhibiting any signs of 
disease, and these cases would have to be considered normal. A per- 
sistent increase of temperature of the body without exhibiting any 
particular local or general disease indicates tuberculosis somewhere 
in the system. An increase during tuberculosis indicates that the 
disease is advancing, with new complications forming. In pneumo- 
nia a temperature wdiich never goes beyond or higher than 102° F. 
does not indicate soft infiltration in the lungs; but a persistent tem- 
perature of 104° or more indicates a severe attack. In acute rheu- 
matism 104° is an alarming symptom. In exanthematous diseases, 
such as measles or scarlatina, the fever rises till the breaking out 
or eruption; the same takes place in small-pox till the pustules 
appear and burst. In tetanus, when all the muscles are in spasms, 
the very high temperature probably depends on the increased decom- 
posing changes of tissues produced by the excessive muscular activ- 
ity. The decomposed tissues probably produce ptomaines in which 
pathogenytes develop, constituting the tetanus bacilli found. In 
jaundice an increase of temperature above the normal indicates a 
pernicious turn. In kidney disease a normal temperature indicates 
chronic Bright’s disease. 
When the internal temperature is below normal, accompanied 
by an abnormally low pulse, there is possibly either some pure 
bile in the blood paralyzing the sensitiveness of the endothelial 
cells of the heart, diminishing the afferent (sensory) impulse for 
reflex functions to the vaso-motor and inhibitory nervous centres; 
or pressure on these centres, cardiac plexus, or nerves, by a new 
growth; or a cancerous condition somewhere in the system, most 
likely in the liver, or in a neighboring part affecting the liver. A 
case is reported in which the temperature of a person in apparent TEMPERATURE. 
123 
health suddenly fell to 93° F. from intestinal haemorrhage, though 
the blood did not appear in the stools for several days after. 
In fevers the temperature varies from 101° to 106° F. If it ex- 
ceeds the latter the patient is in danger, unless due to a malarial 
affection, in which case it may rise to 105° quickly, although the 
patient may have been apparently well shortly before. Such rise 
usually commences several hours before the beginning of the ague 
paroxysm. If a person recently healthy exhibits a sudden rise of 
temperature to 104° or 105° F., it is usually only an attack of ephem- 
eral, exanthematous, or incipient malarial fever, but not typhoid. 
In the latter the rise of temperature is gradual, being about 1° daily 
above the preceding day until it reaches 105°. The fever is at 
its highest daily at 4 P. M. and 1 A. M., and lowest at about 9 P.M. 
and 5 A. M. If higher in the forenoon than the previous after- 
noon it is an indication that the disease is more severe. At any 
period in the course of typhoid a temperature of 1C6° is alarming, 
a persistent rise to 107° generally terminating in death. A sudden 
rise to from 105° to 107°, or sudden fall below normal temperature, 
usually indicates collapse; this may happen some days before any 
change in the pulse or other signs are observable. 
The most direct and simple means of moderating high tempera- 
ture is by increasing the activity and secretion of the perspiratory 
glands; i. e., by cutaneous perspiration. The quantity of watery va- 
por discharged daily from the whole body is about 43 ounces. Of 
this amount the skin gives off about 26 and the lungs 17 ounces; 
so that the heat given off normally by evaporation is about one- 
fifth the total produced in the body. 
In growing plants heat is actively produced, but very rapidly dis- 
sipated owing to the extent of surface exposed to evaporation by 
their leaves and branches. If this loss be artificially limited, the 
elevation of their temperature becomes apparent, and may be esti- 
mated. During germination and blooming the development of 
heat is much more rapid. (For additional information on tem- 
perature, see chapters on Respiration, Circulation, and Medulla 
Oblongata.) CHAPTER XII. 
THE NERVOUS SYSTEM. 
In structure, the nervous system consists of gray and white sub- 
stances and nerve-fibres. The gray substance is composed of collec- 
tions of nervous centre cells intermixed, or mingled, with nerve- 
fibrillae. It constitutes the external portion, or convolutions, and 
various ganglia in the central part and about the base of the brain, 
the central portion of the spinal cord, and isolated ganglionic mass- 
es in the sympathetic system. These latter ganglia are found in 
different parts of the body. Every collection of gray substance is 
termed a nervous centre. The white substance of the brain and spi- 
nal cord is composed of nerve-fibrillae, and is found in the internal 
portion of the brain and external portion of the spinal cord. 
Anatomically and physiologically, the nervous system comprises 
two great divisions—the Cerebro-spinal and the Sympathetic. 
The Cerebro-Spinal System consists of the brain, spinal 
cord, and nerves emanating therefrom. It possesses the function 
of bringing not only its own organs, but also all others of the body, 
into relation one with another, so that all parts are co-ordinated in 
one harmonious whole, while some of its organs are concerned in 
mental processes in a manner to be presently explained. On its 
organs, sensation and motion also partly depend. Its nerve-fibres are 
distributed to the organs of the senses, to the voluntary muscles and 
the integument, as well as to the external openings and termina- 
tions of internal passages. They also furnish the principal nerve 
supply to the heart, muscles of respiration, and some other involun- 
tary muscles. 
The involuntary muscles and the various layers of muscular 
fibres in the internal organs are not directly dependent on the 
cerebro-spinal system, as they owe their power of contraction to the 
influence of the sympathetic system and possess this power to some 
degree within themselves. (For the action of the sympathetic system, 
see the chapter on Sympathetic System.) The bladder, stomach, 
and intestines, for example, are enabled to act upon their con- 
tents, partly through their own inherent function of muscular move- 
ment, and their direct communication with the sympathetic system. 125 
THE NERVOUS SYSTEM. 
Some muscles are both voluntary and involuntary in their function, 
and are termed mixed, as, for instance, those of respiration. 
The function of the nervous system is to associate the different 
parts of the body into one harmonious whole and to bring the va- 
rious organs into mutual relationship. This correlation of func- 
tion is termed sympathy, and is accomplished by either a physical 
or mental impression from a direct or indirect stimulus, and may 
affect only a part of or the entire body—physically, as by an electric 
current; or as a solution of atropia upon the cornea.produces dilata- 
tion of the pupil by paralyzing the muscular fibres of the iris. A 
physiological action becomes manifest when food is taken into the 
stomach, causing the secretion of gastric juice. The digestion of 
food stimulates the gall-bladder to empty itself into the duodenum; 
the presence of food in the mouth, the act of mastication, or even 
the aroma of a favorite dish, each effects the secretion of saliva by 
the parotid, submaxillary, and buccal glands, together known as 
the salivary glands. Mental excitation may produce perspiration. 
The Brain, or Encephalon, comprises all that portion of the 
nervous substance within the cav- 
ity of the cranium. It is divided 
into the cerebrum, cerebellum, pons 
Varolii, and medulla oblongata. 
These are subdivided, forming a sym- 
metrical series of minor nervous cen- 
tres, connected with each other and 
the spinal cord by tracts of white 
substance; i. e., by nerve - fibrillse. 
The longitudinal fissure (D, E, F, 
Fig. 24) divides the brain into two 
equal hemispheres. 
The principal brain centres (Fig. 
25) are connected by intermediate 
nerve-fibrillae, though each centre 
has special functions independent of 
the others. Again, the cerebral areas 
(centres) have special connections 
with sympathetic ganglia; as, for ex- 
ample, a person may be blind with 
one or both eyes, with or without loss 
of normal movements of the iris, 
eyes, or other functions. This is true 
Fig. 24. 
Diagram of Corpus Callosum. 
A, White substance of the cere- 
bral hemispheres. B, Fissure 
of Sylvius. C, Corpus Callosum. 
D, Longitudinal fissure, extend- 
ing from F to E. E, Posterior 
aspect of the longitudinal fissure. 
F, Anterior aspect of the longi- 
tudinal fissure. 126 
THE NERVOUS SYSTEM. 
of all sense organs. The greatest quantity of gray substance is at 
the sulci, or grooves (fissures), of the brain convolutions. The con- 
volutions, as well as the fissures, differ in each individual brain; 
but four fissures are similar in all human individuals: viz., the long- 
itudinal, Sylvian, Rolando, and parietal. 
Fig. 25. 
Diagram of the principal nervous centres of the brain. 
A, Anterior cerebral lobe. B, Middle cerebral lobe. C, Posterior cerebral 
lobe. D, Cerebellum. T, Tentorium cerebelli. S, Sylvian fissure. 
1, Olfactory bulb. 2, Corpus striatum. 3, Optic thalamus. 4, Corpora 
quadrigemina. 5, Crus cerebri. 6, Pineal gland. 7, Pons Varolii. 8, Oliv- 
ary bodies of the medulla oblongata. 9, 10, and 11 ,Medulla oblongata. 10, 
Anterior pyramid of the medulla oblongata. 11, Restiform body of the me- 
dulla oblongata. 
Each cerebral hemisphere is divided, especially on its inferior or 
under surface, into three lobes—the anterior, middle, and posterior 
(A, B, C, Fig. 25). In pressing apart the hemispheres we find the 
corpus callosum, or commissure of the brain (C, Fig. 24). This is 
a thick, white stratum of transverse fibres at the bottom of the 
longitudinal fissure, connecting the two hemispheres of the brain. 
It is about four inches long, forming the roof of the lateral ventri- 
cles. These ventricles have prolongations, or horns, extending into 
the three lobes. Beneath, and almost inclosed by the corpus cal- 
losum, is the fifth ventricle; below this is the third ventricle (3, 
Fig. 26), which communicates downwards by a narrow passage 
with the fourth ventricle in the medulla oblongata. THE NERVOUS SYSTEM. 
127 
The chemical composition of a healthy adult brain is given in 
the following table:— 
Water about 73 per cent. 
Fat “ 12 “ “ 
Albuminous matter “ 8 “ “ 
Salts “ 5 “ “ 
Phosphoric acid “ 2 “ “ 
Total 100 
In insane persons the salts have been found to be only about 2$ 
per cent. 
The supply of blood to the brain is by 
way of four arteries—the two internal carot- 
id and the two vertebral arteries. Their in- 
tercommunication, through the circle of Wil- 
lis (Fig. 27), enables the brain to receive its 
proper amount of nutrition, even should one 
artery only convey the blood to the brain. 
If the circulation is interfered with or 
stopped for a moment, insensibility immedi- 
ately follows, whether it be from disease of 
the cerebral arteries or from embolism. 
Haemorrhage upon the surface of the cere- 
bral hemispheres produces coma, but if haem- 
orrhage occurs in the substance of the cere- 
bral ganglia — the corpora striata or optic 
thalami—it produces hemiplegia. 
Galvanization of the dura mater on one 
side of the head produces muscular twitch- 
ing on the same side of the body; but gal- 
vanization of the cerebral convolutions on 
one side excites muscular action on the op- 
posite side of the body. This is because of 
the decussation of the nerve-fibres at the 
upper part of the spinal cord. As a rule, 
neither the white nor the the gray substance 
of the hemispheres is excitable under ordi- 
nary artificial stimulus, unless it reaches the 
deeper parts of a ganglion. 
The Cerebrum is the largest portion of the encephalon, or brain, 
forming the whole upper and anterior part (A, B, C, Fig. 25). The 
longitudinal fissure divides it into hemispheres (E, F, Fig. 24). The 
upper surface of the cerebrum is thrown into winding convolutions, 
Fig. 26. 
Diagram of the ventri- 
cles of the brain. 
1 and 2, Lateral vent- 
ricles. 3, Third ventri- 
cle. 4, Fourth ventricle. 
5, Fifth ventricle. 6, 
Sixth ventricle, or cen- 
tral canal of the spinal 
cord. 7, Foramen of 
Monro. 8, Aqueduct of 
Sylvius. 
fibrous bundles of the 128 
THE NERVOUS SYSTEM. 
separated by deep grooves (sulci), into which processes from the 
pia mater project. The number and extent of the convolutions 
bear a relationship to the intellectual power of the individual. 
Some of the lower animals have many cerebral convolutions, but 
they are shallow; while others have few or none; the brute fol- 
lows his instincts, but asks not the reason of them. The exterior 
of the cerebrum is a gray, cortical, bark-like substance; the interior 
consists of ganglia of gray, and white medullary substances. The 
nervous centres belonging to the cerebrum are as follows: the gray 
convolutions covering the anterior, middle, and posterior lobes (A, 
B, C, Fig. 25); the olfactory lobe, or bulby enlargement of the 
olfactory nerve (1), being concealed beneath the anterior portion of 
the anterior cerebral lobe; corpus striatum (2); optic thalamus (3); 
corpora quadrigemina (4); crus cerebri (5); and pineal gland (6). 
Fig. 27. 
Diagram of the Circle of Willis. 
AA, Internal carotid arteries. B, Anterior cerebral arteries. CC, 
Sylvian arteries. DD, Posterior communicating arteries. EE, Pos- 
terior cerebral arteries. H, Basilar artery. V, Vertebral arteries. 
On the cells of centres of the cerebral convolutions, the opera- 
tions of the intellect in man’s present state partly depend. This 
includes internal and external sensations, inasmuch as to each 
external sense-organ a proper centre-cell in the cerebrum is united, 
without which there is no external sensation; internal sensation, THE NERVOUS SYSTEM. 
129 
inasmuch as each external sense must have its own internal 
organ, as will be shown afterwards; the operations of the intellect, 
inasmuch as the intellect, although a faculty of the soul, and 
therefore inorganic, cannot act in its present state—i. e., while 
the soul is united to the body—unless the operation of the im- 
agination (one of the internal senses, having its organ in the 
cerebrum), depending primarily on the external senses, precedes 
and accompanies it. 
Physiologically, the cerebrum is not directly essential to life; 
since respiration and circulation are but indirectly governed by 
the cerebral centres. Life may, therefore, continue for a time 
even if the cerebrum be diseased, injured, or partially destroyed, 
as long as the respiratory and circulatory centres of the medulla 
oblongata remain unaffected. A lesion of the cerebral convo- 
lutions affecting the gray substance, or an impairment of its 
functions, causes either a partial or total suspension of the mental 
functions, for the reason above assigned: such as reason, which 
is an act of the mind by which is determined the agreement 
or disagreement, the identity or diversity, of two things, by com- 
paring them with a third; and judgment, an act of the mind 
by which it affirms the agreement or disagreement of two concepts 
or ideas.* When these functions, depending on cerebral activity, 
are abnormal, then we say that the individual so affected is 
insane and incapable of performing legal requirements and 
duties; and his responsibility to God and man ceases. Insanity, 
therefore, may be properly defined: Impairment of cerebral organs 
affecting reason and judgment. Insanity may exhibit itself in 
monomania, mania, or dementia. As previously stated, it has 
been claimed that the salts of the brain are present in a deficient 
quantity; though abnormal functions of cerebral areas may man- 
ifest themselves even without visible physical lesion being ob- 
servable after death. 
*“It is one and the same power of the soul that understands, 
reasons, and judges. That power which is concerned in the acts of 
knowing, he it manifested as understanding, reason, or judgment, is 
what is generally called the mind. It is, however, sometimes con- 
sidered as the three powers, or faculties, of the soul taken together— 
the will, memory, and understanding; the soul being the spiritual 
substance, together with its perfections.” 130 
THE NERVOUS SYSTEM. 
The Corpora Striata, (2, Fig. 25; and C, Fig. 28), one in each 
cerebral hemisphere, are partly separated by the two optic thalami. 
Their gray masses are striated with white fibres, hence their name. 
Each corpus consists of gray matter imbedded in the white substance 
of said hemisphere. In the center the corpus contains a layer of 
white matter (nerve-fibrillse) dividing its gray matter into two por- 
tions; the internal portion is termed nucleus caudatus, the external 
portion nucleus lenticularis. A layer of white matter separates the 
latter from a body of gray ma- 
ter termed claustruvi and from 
the island of Reil. The function 
of the claustrum is not known. 
Motor fibres from the convo- 
lutions (3, 3, Fig. 28) proceed 
to the corpus, then to the an- 
terior columns of the spinal 
cord; since voluntary impulses 
emanating from the convolu- 
tions pass to the cells of this 
corpus, where they may be mo- 
dified, reinforced, or brought 
into harmoniously acting mo- 
tor impulses (C, Fig. 28). This 
centre is in communication 
with voluntary muscles; and if 
the corpus striatum on one side 
of the brain be injured, hemi- 
plegia of the opposite side of the 
body results, on account of the 
decussation of the nerve-fibres. 
Impairment of both corpora 
may lead to permanent loss of 
voluntary motion of the body. 
The Optic Thalami (tha- 
lamus-& bed), one in each cere- 
bral hemisphere (2,Fig.25; and 
D, Fig. 28), are situated below 
the corpus callosum and partly 
between the corpora striata, se- 
parating these bodies. They are two oblong masses of gray substance, 
having in the center some white matter consisting of nerve-fibrillae, 
Fig. 28. 
Diagram of the brain centres. 
AA, Cortex and cerebral convolutions. 
B, Olfactory bulb. C, Corpus striatum. 
D, Optic thalamus. E, Corpora quadri- 
gemina. S, Pineal gland. H, Crura cer- 
ebri. T, Tegmentum and H, Crusta of 
the crura cerebri. P, Pons Varolii. M, 
Medulla oblongata. 
1, Longitudinal fissure. 3, Place of the 
corona radiata and lenticular nucleus— 
the lines indicate motor fibrillar commu- 
nication. 4, Motor fibrilla tract. 5, Sen- 
sory fibrilla tract. 7, One optic nerve 
fibrilla. 8, Fibrillar communication of 
sensory area of sight. 9, One oculomoto- 
rius fibrilla. 10, One commissure fibrilla. tup: nervous system. 
131 
forming the communication with the more centrally located cells of 
the gray substance. Sensory fibres of the posterior columns of the 
spinal cord proceed to the optic thalami (D, Fig. 28), thence to cere- 
bral convolutions. The thalamus is the modifying and distributing 
centre between the brain areas of sensation and peripheral sensory 
organs. Consequently, if in one hemisphere it is destroyed, hemi- 
ansesthesia of the other side of the body results, on account of the 
decussation of the nerve-fibres. The corpora striata and optic 
thalamus together are sometimes termed the basal ganglia. The 
conflicting results of experiments in regard to local stimulation, or 
lesion of either one of these two ganglia, in reference to loss of 
sensation, motion, or both, may possibly be accounted for by the 
close relationship of the ganglia and their nerve-fibrillse. 
The Corpora Quadrigemina consist of two rounded tuber- 
cular eminences in each cerebral hemisphere, and are separated by 
a slight depression (4, Fig. 25; and E, Fig. 28). They are situated 
behind the third ventricle and beneath the posterior portion of the 
corpus callosum, laterally joining with the optic thalamus and the 
upper surface of the crura cerebri. They are solid bodies, composed 
of white matter externally and gray within. In function they 
govern the movements of the iris as well as the harmonious co- 
ordination of the movements of both eyes. If the function of one of 
these bodies becomes impaired, the iris on the opposite side cannot 
contract; or, if totally destroyed, sight is lost, although, apparent- 
ly to the observer, the eyeball has not undergone any pathological 
change. Its irritation simply produces contraction of the iris. In 
impairment of the corpora quadrigemina the equilibrium of the 
body is interfered with. (See Semi-circular Canals.) 
The Pineal Gland, so called from its pine-cone shape, lies on the 
median line beneath the posterior portion of the corpus callosum, 
partly above and behind the third ventricle (6, Fig. 25; and S, Fig. 
28). It projects backward and downward between the tubercula 
quadrigemina. Its function is not known, although the gray mat- 
ter connected with it and projecting to the medulla oblongata may 
possibly be an auditory ganglion, associating it with the organ of 
hearing and the auditory area in the cerebrum, in the accomplish- 
ment of the sensation of sound. 
The Crura Cerebri are two thick strands, or bundles, of white 
substance (5, Fig. 25; and H, Fig. 28); each crus being about three- 
quarters of an inch in length and resembling a leg (hence its 
name). In the center of each crus is a mass of dark-gray matter 132 
termed the locus niger, from which some fibres of the oculomotorius, 
or third nerve, originate, serving for numerous and compli- 
cated movements of the eyeball. The posterior portion of the crus 
is termed the tegmentum (T, Fig. 28), which is the path for the sen- 
sory fibres. The anterior part is called crusta (H), and is the chan- 
nel for the motor fibres; consequently, it is at the crura cerebri 
where the spinal sensory and motor fibres enter and depart from 
the cerebrum. Each class of fibres forms a separate tract; the 
sensory, from the posterior part of the spinal cord, proceeding from 
the crura to the optic thalami (D, Fig. 28); thence (5) to the cerebral 
convolutions. The voluntary motor fibres (3, 3,), from the cere- 
bral convolutions, proceed to the corpora striata (C); thence to the 
crus cerebri and cerebellum; thence,some to the voluntary muscles 
of the head, others to the anterior portion of the spinal cord and 
the organs of the body and limbs. 
The Valve of Vieussens is a medullary layer in the Sylvi- 
an aqueduct, or canal, leading upward and forward from the 
fourth to the third ventricle (8, Fig. 26), and forming a part of the 
roof of the fourth. At the side of the valve originates the Trochlearis 
(Patheticus) nerve (fourth). 
Below the cerebrum follows the pons Varolii (7, Fig. 25; and P, 
Fig. 28); while behind the pons and posteriorly below the cerebrum 
is the cerebellum (D, Fig. 25); anterior to the latter and below the 
pons, the medulla oblongata. 
The Pons Varolii (pons, a bridge), is sometimes called tuber 
annulare. It is a thick, flattened band of alternate layers of transverse 
and longitudinal white fibres, with an intermixture of gray matter, 
and connecting as by a bridge the cerebrum, cerebellum, and the 
medulla oblongata (7, Fig. 25; and P, Fig. 28.) It is divided in 
the median line by the longitudinal fissure, each half containing 
centre cells which give origin of some fibres of the fifth, sixth, and 
eighth cranial nerves. Consequently, it is a nervous centre, and 
at the same time affords a passage for tracts of nerve-fibrillae to and 
from the cerebrum, cerebellum, and medulla oblongata. 
The Cerebellum or small brain (D, Fig. 25; and 0, Fig. 29), is 
beneath the posterior lobes of the cerebrum, and separated from it 
by a membrane called the tentorium cerebelli (T, Fig. 25). Like the 
cerebrum, it is convoluted and divided into halves by the longitu- 
dinal fissure. The cortex of its convolutions consists of gray matter, 
while its interior is white. The convolutions are smaller than those 
of the cerebrum. In each cerebellar hemisphere the white matter 
THE NERVOUS SYSTEM. THE NERVOUS SYSTEM. 
133 
contains in its center a dentated nucleus or lump of gray matter, the 
corpus dentatum, in the center of which is inclosed some white matter 
of nerve-fibrillse, thereby communicating with the surrounding white 
substances. Some of the fibres of the cerebellum communicate with 
the lateral columns of the spinal cord, enabling the head to maintain 
the proper posture on the trunk. The cerebellum is a part of the 
motor apparatus, and, as it is the reflex centre which governs co-or- 
dinate action, a lesion of its gray substance produces not only inhar- 
moniousness of voluntary movements of muscles and limbs, but also 
disturbs the equilibrium in balancing of the body. It is not the 
centre which governs sexualism, as was formerly supposed. Any 
slight injury to the cerebellum may cause constant agitation of 
the head, limbs, or of both. (See Semi-circular Canals.) CHAPTER XIII. 
MEDULLA OBLONGATA. 
The Medulla Oblongata is the superior enlarged portion of 
the spinal cord, situated within the cranium, extending from the 
upper border of the atlas to the lower border of the pons Varolii, 
and forming a part of the encephalon (8, 9, 10, 11, Fig. 25; M, Fig. 
28; and M, K, L, R, Fig. 29). It is divided in the median line lon- 
gitudinally, each half being subdivided by grooves into four col- 
umns— the anterior pyramid, lateral tract, the restiform body, the 
posterior pyramid. The anterior pyramid is a continuation of the 
anterior column of the spinal cord. The lateral tract (embrac- 
ing the olivary body) is a continuation of the lateral column of the 
cord. The restiform body is a continuation from the posterior col- 
umn of the cord interiorly, and extending to the cerebellum supe- 
riorly. The posterior pyramid is a thin, cord-like continuation 
of the posterior median column of the cord. 
The Olivary Body (8, Fig. 25; and L, Fig. 29), so named from its 
olive-shape, is situated on the lateral tract, behind the upper portion 
of the anterior pyramid. It contains masses of centre-cells. In the 
groove between the olivary and the restiform body arise some fibres 
of the glosso-pharyngeal, and at the groove between the olivary and 
pyramidal bodies arise some fibres of the hypoglossal nerve. 
The Fourth Ventricle is a lozenge-shaped space in the medulla 
oblongata, formed by the expansion of the central canal of the me- 
dulla and the convergence of the posterior pyramids (4, Fig. 26). 
The floor of the ventricle is formed by the posterior surface of the me- 
dulla, the roof by the valve of Vieussens at the aqueduct of Sylvius 
(8) and anterior inferior surface of the cerebellum. This ventricle 
communicates upward by said aqueduct with the third ventricle. 
In the lower part of the anterior and internal aspect of the me- 
dulla most of the nerve-fibres of the two hemispheres of the brain 
cross obliquely and in bundles to the opposite side of the spinal 
cord. This crossing is termed “ decussation of the pyramids.” 
The medulla oblongata is a continuation of the spinal cord, al- 
though placed just within the cranium (evidently for protection 
from injuries to which the cord is more liable). It is the most im- THE MEDULLA OBLONGATA. 
135 
portant portion of the brain for the immediate continuation of life, 
as it contains the reflex centres presiding over respiration and cir- 
culation. It is that portion of 
the brain giving origin to nerve- 
fibres, more or less, of all cranial 
nerves, except the olfactory and 
the optic, and these even are in- 
directly connected with it. Con- 
sequently, in the centres of the 
gray matter of the medulla ob- 
longata, the reflexes are effected 
for respiration, circulation, diges- 
tion, absorption, assimilation, 
secretion, and intestinal and 
capillary peristalsis. It also sup- 
plies nerve-fibres to the muscles 
and skin of the head and face, 
all mucous membranes, secreting 
glands of the skin, and other 
secreting organs. It likewise af- 
fords some fibres for three organs 
of the external senses; viz., taste, 
sight, and hearing. 
The medulla oblongata is real- 
ly the central point from which 
impulses are reflected affecting 
the whole vital organism; it con- 
tains the vaso-motor centre which 
influences the whole vascular 
system by controlling the dilata- 
tion and contraction of the blood 
vessels; the centre from which the 
motor impulses are reflected to 
enable the muscles of the palate, 
pharynx, and oesophagus to pro- 
duce successive co-ordinate and 
necessary movements for deglu- 
tition, or swallowing; the centre by which the various muscular 
movements made in speech are co-ordinated; the salivary excitor 
centre; the cardio-inliibitory centre for the regulation of the action 
of the heart. Kirkes mentions “ the so-called diabetic centre, 
Fig. 29. 
Diagram of the medulla oblongata 
and cranial nerves. 
A, Anterior cerebral lobe. B, Middle 
cerebral lobe. C, Part of posterior cer- 
ebral lobe. D, Mammillary eminences. 
E, Crura cerebri. H, Pons Varolii. 
K, Pyramidal bodies. L, Olivary body. 
M, K, R, L, Medulla oblongata. 0, Cer- 
ebellum. R, Restiform body. S, Section 
of the medulla from the spinal cord. 
1, Olfactory nerve. 2, Optic commis- 
sure, formed by the optic tracts. From 
this decussation outward the bundles 
of fibres are termed the optic nerves. 
3, Oculomotorius nerve. 4, Trochlear 
nerve. 5, Trifacial nerve. 6, Abdu- 
cens nerve. 7, Facial nerve. 8, Audito- 
ry nerve. 9, Glosso-pharyngeal nerve. 
10, Pneumogastric nerve. 11, Spinal 
accessory nerve. 12, Hypoglossal nerve. 136 
THE MEDULLA OBLONGATA. 
which, if irritated in the medulla oblongata, causes glycosuria, this 
peculiar result being due to the vaso-motor changes and increased 
flow of blood to the liver.” The diabetic result may possibly be 
brought about from the irritation of the vaso-motor centre-cells 
giving rise to nerve-fibrillse passing to the liver only. 
The blood flowing through the medulla supplies nourishment in 
order to keep up the energy of the cells. A high temperature 
acts as a powerful stimulus on the heart and lungs, increasing the 
stimuli for reflex action of the centres in the medulla oblongata. 
Cold lowers the stimulation, the reflex functions, and the temper- 
ature. 
Normally, the vaso-motor and respiratory centres receive impulses 
for reflex activity—the former from the beginning of the formation 
of the foetus in utero, the latter from birth, and both to the end of 
life. 
The Respiratory Centre is situated at the Calamus Scriptorius, 
at the floor of the fourth ventricle. It is termed the vital point, and 
consists of two slight protuberances of gray centre-cells in each 
hemisphere of the medulla oblongata. The stimulation to this 
vital point is derived from the lungs, which are stimulated 
by the carbonic acid of the venous blood in the lungs. The 
oxygen of the inhaled air produces a satisfying influence. Con- 
sequently, for normal respiratory actions it is required that 
carbonic acid and oxygen be present in moderation. If the 
lungs are oversaturated with the elements of either one (of 
carbonic acid or of oxygen) the stimulation to the lungs and 
to the respiratory reflex centre ceases, and apncea, or cessation 
of the respiratory movements, results. Respiratory stimulation, pro- 
ducing over-excitation of the respiratory centre, gradually exhausts 
it, resulting in asphyxia. This may happen even to the embryo in 
the uterus, if the mother’s blood becomes deranged in that manner. 
Respiratory irregularity is one of the most minacious symptoms in 
brain affections, showing that the reflex centre of the medulla 
oblongata is affected. This phenomena depends on an improper reflex 
action of the medulla to the respiratory organs. A suspension of 
either sensation, volition, or intellectual power does not necessarily 
indicate immediate danger of death. Cerebral apoplexy, either from 
haemorrhage at the surface of the hemispheres or a haemorrhage in 
the cerebral ganglia, is not at once fatal; but it is so when occurring 
at the floor of the fourth ventricle in the medulla. THE MEDULLA OBLONGATA. 
137 
Deglutition is under the reflex control of the medulla, but mastication 
is voluntary, continued or arrested at will, while swallowing oi 
deglutition is voluntary only from the mouth into the pharynx, after 
which it is reflex and involuntary; and, when commenced, can- 
not be arrested at will, and may therefore be performed after all 
voluntary power has disappeared. Swallowing, when no longer 
possible, or accompanied by choking during disease, and this when 
the throat is clear, indicates that the reflex centre of the medulla 
has become seriously affected, and death near at hand. Exercise 
of the voice or exhibition of emotion requires the co-operation of the 
cerebrum and pons Varolii; but the immediate mechanism in the 
larynx by which sound is produced has its nervous centre in the 
medulla. The fibres of the hypoglossal nerve originate in the me- 
dulla, and carry the motor impulses to the muscles of the tongue, 
and regulate the condition of the rima glottis. Disease of said 
nerve paralyzes these muscles, and makes articulation difficult or 
impossible. In this affection, the inability to speak is very evident 
from ataxic aphasia, which is of cerebral origin, consisting in loss of 
power in the necessary nervous combinations. CHAPTER XIV. 
NERVOUS CENTRES AND REFLEX ACTION. 
In the nervous system every collection of gray matter is termed 
a Nervous Centre. A nervous centre is an area or aggregation 
of gray cells, with functions peculiar to each group; so that a mass 
of said matter generally has many centres, with various functions. 
In fact, every nervous centre concerned in reflex impulses has the 
power to inhibit, restrain, or accelerate them. The cells of nervous 
centres are round or irregular in shape, and consist of a soft, semi- 
transparent, finely granular albuminous substance, their size vary- 
ing from 8 to 130 micromillimetres in diameter. The largest cen- 
tre cells are found in the anterior horns of 
the spinal cord, the smallest in the sympa- 
thetic ganglia, the middle-sized in the 
brain centres. Most centre-cells of the cere- 
bro-spinal system have processes commu- 
nicating with the axis-cylinders of the 
nerve-fibres. Some cells have a single pro- 
cess, others more, and are severally termed 
unipolar, bipolar, and multipolar (Fig. 30). 
. TT . . „ „ The nucleus of the cell is distinct, and 
A, Unipolar cell. B, Bipo- .. , _ , . , . ' . 
lar cell C Multipolar cell contains a well-defined nucleolus indirect 
2, Process through which communication with the axis-cylinders of 
the nerve-fibril la? pass to or minute nerve-fibrillae (2), which communi- 
from the cell. Ihe axis-cyl- ca{e either with another nervous centre-cell, 
inders of the nerve-fibrillfe . n. , ... . , , , 
. .iU or m a direct manner with peripheral ter- 
are m communication with 1 r 
the nucleolus of the cell. 4, ruination cells, such as a tactile corpuscle, 
Axis-cylinder process. Pacinian body, terminal bulb, or a termin- 
al plate. (See chapter on Nerve-fibres and 
Their Terminals.) Some of the nervous centre-cells have a process 
which terminates abruptly (4), appearing to have no communica- 
tion with nerve-fibrillae. Such a process is termed an axis-cylinder 
process, the function of which is unknown. 
The manifestations, or functions, in which the different nervous 
centres are involved, either singly or in combination, may be said 
Fig. 30. 
Diagram of nervous 
centre-cells.. NERVOUS CENTRES AND REFLEX ACTION. 
139 
to constitute nine classes—five for the external senses, and four for 
the internal. The centres involved with the five external mani- 
festations have all been determined to be connected with the organs 
of sight (eye), hearing (ear), smell (nose), taste (tongue and mouth), 
and touch. The centres of the four internal sense-organs, the loca- 
tions of which have not yet been determined, are those for the mani- 
festation of common sense, the imagination, estimative faculty or 
instinct, and sensitive memory. (See chapter on Senses.) 
The impulses which call the nervous centre-cells into action are 
derived from impressions by stimuli on either the external or inter- 
nal organs, through sensory nerve-fibres. The nervous centre, 
then, directs, distributes, or forwards an impulse to either periph- 
eral or internal organs direct, or to another nervous centre; the lat- 
ter to either direct, modify, analyze, classify, redistribute, or check 
them, and to convert them into impulses which are transmitted 
through motor fibres to distant organs. Some groups of centre-cells 
act constantly or periodically. Of those acting constantly the vaso- 
motor and respiratory centres in the medulla oblongata are good 
examples. It is well known that with volition in suspense, as when 
asleep, actions by reflex are much more severe; in fact, when awake, 
many can be entirely prevented. Slight epileptic attacks, and con- 
vulsions of children from indigestion, may often be prevented by 
wdll power during waking hours, which during sleep result in severe 
attacks. Stimulation of a sensory organ may produce various 
reflex actions simultaneously, especially in children. For instance, 
powerful stimulation of the skin of the foot may cause movement, 
in bending and twisting the limbs and body; secretion, such as 
tears; excretion, such as urine or sweat; or pain in the organ stim- 
ulated. Powerful stimulants increase the reflex excitability, while 
narcotics diminish it. 
Rsflox, physiologically considered, takes place only in a nervous 
centre, and refers to the action of an organ (muscle, respiratory, 
circulatory, or secretory organ) receiving its primary impression 
from stimulus directly, or indirectly through impulses from another 
organ. The terminal sense-organs do not transform the outer ener- 
gy into physiological energy, hut the stimulus excites changes in 
the terminal organs in producing activity within them. The indi- 
vidual may or may not be conscious of this action. Sensation is the 
vital organic representation. (See chapter on Senses.) Property 
applies to the endowment of a nerve, nerve-fibre terminal, or, mus- 
cular fibre, to respond to a stimulus; the action of response is 140 
NERVOUS CENTRES AND REFLEX ACTION. 
their irritability. Irritation is always followed by the phenomena 
noticeable in living matter only; but does not involve the exercise 
of the inherent force of the irritant itself. Excitability is the spe- 
cial irritability of living matter, and may be affected by a variety 
of stimuli: — 
1. Normally, by influences on, or changes in, the terminal or cen- 
tral organs. 
2. Thermally, by variation of temperature. 
3. Chemically, by the application of acids, alkalies, metallic 
salts, etc. 
4. Electrically, by continuous or induced currents. 
5. Mechanically, by intermittent pressure, pricking, beating, sec- 
tion, etc. 
Heat increases, while cold diminishes, excitability. When a 
nerve or a muscle is at absolute rest for a long period its excita- 
bility diminishes; or, if such tissue be inactive beyond a certain 
time, it wastes, becoming thinner, and 
degeneration of its own substance re- 
sults. 
Reflex action requiring the co-opera- 
tion of cells of several centres in order to 
act harmoniously towards certain results 
is termed co-ordination. Either voluntary 
or involuntary external activity is, pri- 
marily, involved in reflex action, which 
essentially requires seven agents: a sen- 
sory receiving organ (A, Fig. 31) con- 
nected to a sensory nerve-fibre (B), in 
communication with a nervous centre or 
cell (C), which receives and transfers a 
nerve impulse through a nerve-fibrilla 
(D), to a nervous centre or cell (E), this 
forwarding an impulse through a motor 
nerve-fibre (L) connected with an internal or a peripheral organ 
(M). Nervous centres are generally connected with each other by 
nerve-fibrillae; many of the latter together constituting the medul- 
lary or white nervous substance of the brain and spinal cord. 
The co-ordinate movements and reflex acts may be effected in 
three different ways: 1. From internal organs through the sympathetic 
and cerebro-spinal system to voluntary muscles and sensitive sur- 
faces. 2. From sensitive surfaces through the cerebro-spinal and 
Fig. 31. 
Diagram of the reflex act. 
A, Sensory receiving organ. 
B, Afferent (sensory) nerve- 
fibre. C, Nervous centre-cell. 
D, Nerve-fibrilla between 
centre-cells. E, Nervous cen- 
tre-cells. L, Efferent (motor) 
nerve-fibre. M, Muscular, 
secreting, or excreting organ. NERVOUS CENTRES AND REFLEX ACTION. 
141 
sympathetic system to involuntary muscle-fibres and secreting 
organs. 3. From one internal organ to another, through the sym- 
pathetic nervous system. 
It is owing to reflex action that the normal activities of the vari- 
ous organs, and their functions are maintained; as, for instance, 
the contact of food with the mucous membrane inciting the mus- 
cular coat of the intestines to peristaltic action; the gall-bladder 
discharging its contents into the duodenum during the process of 
digestion; the circulation of the blood becoming accelerated during 
digestion in order to facilitate glandular secretion. It is also due 
to reflex action that all kinds of disturbances of the physiological 
equilibrium are produced—such as convulsions in children from the 
irritation of undigested food; diminished or unnaturally increased 
appetite from any diseased part of the system; mental depression 
interfering with the digestive process or with secretion; terror, caus- 
ing the pupil of the eye to dilate, or the action of the heart to be- 
come increased or diminished; in early pregnancy, the change in 
the condition of the uterine mucous membrane causing nausea and 
vomiting; fright, interfering with the menstrual function, or pro- 
ducing premature delivery or other disagreeable occurrences; local 
inflammation, arousing the general circulation, since increased heat 
augments reflex excitability. 
Sympathy of one organ with another is the very foundation of 
the maintenance of life; for, if the action of one organ is increased 
and other organs act normally, the affected organ would soon 
become exhausted; but if the action of one is increased and others 
diminished through vital equilibrium, the system suffers less. So, 
on the other hand, the continued violent action of one part may 
affect others in such a degree as to cause cessation of all. These 
sympathetic functions are governed by reflex actions, and are fur- 
ther illustrated by the sympathy of the eye with the stomach, as in 
amaurosis, strabismus, and even hemiplegia from indigestion; in 
diarrhoea arising from coldness or wetness of the integument; in the 
sympathy between the stomach and the liver; of the intestines with 
the stomach and the brain; of the skin writh the parts below; of the 
uterus or kidneys with the stomach; and, finally, in the circulation 
of the entire system, aroused by an inflammation or disturbance 
of one part. 
Certain reflex actions may be controlled, or even prevented, by the 
will. External reflexes are illustrated by the contraction of the 
abdominal muscles in response to stimulation of the skin over the 142 
NERVOUS CENTRES AND REFLEX ACTION. 
mammae, sometimes called abdominal reflex; the tickling abdominal 
reflex, or contraction of abdominal muscles by stroking the skin 
over the side of the abdomen; the plantar reflex, by tickling the 
sole of the foot, producing movements of the toe3, or of the toes and 
foot; the pupil reflex, being its dilation (the iris) on stimulation of 
the skin of the neck, or its contraction on exposure of the eye 
to light. CHAPTER XY. 
NERVE-FIBRES AND THEIR TERMINALS. 
Nerve-fibres are cylindrical filaments, which generally run 
parallel in groups or tracts (A, B, Fig. 32). They are composed 
of an external sheath (1), axis-cylinder (3), and a medullary layer 
between these two (4). The sheath is a colorless, elastic, tubular 
membrane, which protects the internal parts of the fibre. The 
medullary layer is termed the white substance of Schwann. It is a 
transparent, oily substance, giving the fibre a white, shiny appear- 
ance. Physiologically, it confines the transmission of nerve-fibre 
currents (impulses) to the axis-cylinder, a pale, homogeneous gran- 
ular, cylindrical cord in the center of the nerve-fibre. It differs 
from the medullary layer, which is nearly fluid in consistency, in 
being more solid and elastic, extending the entire length of the 
fibre, and of which it is the most essential element, since the cur- 
rents pass through it. 
Nerve-fibres vary in diameter from about 2 to 16 micromilli- 
metres; the smallest being in the brain and spinal cord, the largest 
in the nerves of the periphery. In some parts of the nervous sys- 
tem they also differ in construction, some being medullated and 
others non-medullated, though not differing in function. The latter 
only have no medullary layer, are not so white therefore on ac- 
count of its absence, and are found near the cells of gray substance 
of nervous centres and in nerve terminals. Again, a fibre may have 
a medullary layer through a portion of its course, but. none at its 
termination, as in the cerebro-spinal nerves; or it may originate 
without this layer and after a short distance become medullated. 
When nerve-fibres issue from bony cavities, they usually coalesce 
into bundles, which are held together by a thin connective tissue 
coat termed Neurilemma (A, or B, Fig. 32), derived from the dura 
mater and periosteum. Such a bundle of fibres is called a Nerve 
(A or B), and generally contains both sensory and motor fibres. 
These fibres do not branch or inosculate with each other in the 
nerve, though a fibre may separate from one nerve (2) and join 
another. Each fibre is continuous, and independent of every other, 144 
NERVE-FIBRES AND THEIR TERMINALS. 
from its origin to its final termination; i. e., 
the sensory to the nervous centre-cells, the 
motor to nervous plexuses of motor and 
secreting organs. The neurilemma of the 
nerve is endowed with sensitiveness by vir- 
tue of the cells of the neurilemma; it is, 
therefore, excitable in any part of the 
course of a nerve. 
The white, marrow-like substance of the 
brain and spinal cord is almost entirely 
composed of nerve-fibrillae, which in these 
positions do not run in separate covered 
bundles as nerves, as the cerebro-spinal 
fibres do on the outside of the skull and 
spine. Near the peripheral termination 
the fibres change both in structure and 
arrangement, since they divide and subdi- 
vide (Fig. 33), yet each branch of the sub- 
division retains all the original functions 
of a nerve-fibre, and form many plexuses, 
the fibrillse of which supply the anatom- 
ical elements of the tissues. In the tissues, 
especially in the skin, there are two of such 
plexuses, a deep and a superficial one, the 
latter being more closely arranged, and 
most intimately associated with anatom- 
ical elements. At the place of subdivision 
into a peripheral plexus, the nerve-fibres 
are constricted (2, Fig. 33); each branch 
that follows the constriction is nearly 
equal in diameter to the fibre before sub- 
division. At the periphery the sensory 
fibres terminate either in tactile corpuscles 
(Fig. 34), Pacinian bodies (Fig. 35), or in 
terminal bulbs (Fig. 36); the motor, in the 
terminal plates (Fig. 37); the first three 
being cell-like bodies. The various forms 
of the terminal cells of nerve-fibres have 
their respective special and separate secret- 
ing and other functions, in the various 
•organs and tissues of the body. 
Fig. 32. 
Diagram of two Nerves 
and Their Fibres. 
A, Nerve, the neurilem- 
ma of which incloses five 
nerve-fibres. B, Nerve, 
the neurilemma of which 
incloses four nerve-fibres. 
1, Sheath of a nerve- 
fibre. 2, Two nerve-fibres 
separating from one nerve 
and joining the other. 3, 
Axis-cylinder in the cen- 
tre of the nerve-fibre. 4, 
Medullary layer, or white 
substance of Schwann, be- 
tween the external sheath 
and axis-cylinder of the 
nerve-fibre. NERVE-FIBRES AND THEIR TERMINALS. 
145 
The Tactile Corpuscle (Fig. 34) is of an oval shape and sit- 
uated in the papillte of the skin, being most numerous near the 
tips of the fingers and in the soles of the feet. They are organs of the 
special sense of touch (organa tactus), most highly developed in those 
Fig. 33. 
Fig. 34. 
Diagram of Nerve-fibre 
Branching. 
Diagram of a Tactile 
Corpuscle. 
1, A nerve with three nerve-fibres, 
2, The constriction of the nerve- 
fibres at their point of branching. 
1, Nerve-fibre sheath. 2, 
Axis-cylinder. 3, Termina- 
tion of the axis-cylinder. 
parts more numerously supplied with tactiles. The corpuscle con- 
sists of a central, transparent, gelatinous mass, surrounded by an 
envelope of connective tissue. It has many transverse elongated 
cells with nuclei, and is supplied by a nerve-fibre, which, on enter- 
ing the corpuscle, loses its sheath (1). The sheath becomes amal- 
gamated with the outer wall of the corpuscle. The medullary layer 
disappears also, so that the axis-cylinder (2) alone enters and ter- 
minates inside the corpuscle. The high degree of sensibility of a 
tactile corpuscle depends on its internal cells and its connection 
with the nerve-fibre. There are differently qualified degrees of the 
sense of touch. Thus, the modification of the sense of touch, by 
which certain qualities, such as softness, roughness, etc., of bodies 
are felt on very delicate contact, must not be confounded with or- 
dinary sensitiveness to temperature, nor with pain, 
which pertains as such directly to the “Common Sense.” It is said 
“as such” because pain has reference, too, to the sense of touch. 
Again, certain narcotic poisons will render a person insensible to 
pressure, pain, or temperature, without, however, affecting his 146 
NERVE-FIBRES AND THEIR TERMINALS. 
appreciation of the quality, for instance, of roughness in a body 
In analgesia he becomes insensible to pain, but remains sensible to 
other impressions pertaining to the sense of touch. ( Vide Senses.) 
The Pacinian Body is oval-shaped (Fig. 35) and consists of 
connective tissue laminae (2), inclosing a transparent, colorless, 
semifluid substance in its central portion. It is found on the per- 
ipheral terminations of some of the cerebral, spinal, and sympa- 
thetic nerves, in the subcutaneous connective tissue of the skin 
some distance beneath the derma, but not in it; also, either between 
or immediately beneath the epithelial cells of the mucous and 
serous membranes; in the conjunctiva and lips, and sensitive or- 
gans of the body. A single branch of a nerve- 
fibre (5) enters the Pacinian body. At the 
point of entrance into the body, the external 
sheath (4) is continuous with the external 
connective tissue lamina (1). The medullary 
layer of the fibre disappears, and only the 
axis-cylinder (3) enters the central portion, 
and continues to its extremity. The Pacinian 
bodies are also organs of touch (organa tactus), 
and are believed to be the organs on which 
sensation depends, such as pressure, pain, etc., 
which are common to all organs. Undoubt- 
edly, the Pacinian bodies differ in size, struct- 
ure, and function, more or less, in each organ. 
A good illustration is afforded in the peculi- 
arity of the sense of touch after the Taliaco- 
tian operation (Rhinoplasty), where a portion 
of the skin of the forehead is partly turned 
downward (not cutting all the nerve-fibres) 
to make a new nose. When the nose itches 
the person scratches the forehead as the seat 
of sensation. This also evidences that exter- 
nal sensation lies in the organ, and not in the 
brain. ( Vide chapter on The Senses.) 
The sense of touch is the most.important and the most necessary 
for the vital economy, as without touch no external impression can 
be produced on any organ. The touch of the ray of light on the eye 
stimulates sight; the touch of the vibrating air (sound) stimulates 
hearing; the touch of substances to the tongue, taste; floating par- 
ticles of matter in the air, smell; substances touching the cesoph- 
Fig. 35. 
Diagram of a Paci- 
nian Body. 
1, Connective tissue 
layer. 2, Concentric 
layers of connective 
tissue. 3, Axis-cylin- 
der. 4, Nerve-fibre 
sheath. 5, Nerve-fibre. 
6, Branch of nerve- 
fibre. 7, Five Pacinian 
bodies and branches of 
a nerve-fibre. NERVE-FIBRES AND THEIR TERMINALS. 
147 
agus, stomach, intestines, stimulate the secretions and peristaltic 
action; the touch of carbonic acid elements in the blood stimulates 
the motion of the heart, lungs, kidneys, liver, and skin to contin- 
ual activity. When the sense of touch in the general economy is 
severely impaired, the person is dying, or, when entirely lost, dead. 
The Terminal Bulb (Fig. 36) is either a round or slightly 
elongated, closed body of connective tissue, containing a fine gran- 
ular substance, and transverse cells with nuclei. It is found within 
the papillae of the mucous membrane of the tongue. A nerve-fibre 
(2) enters the papilla similarly to that of the Pacinian body, the 
sheath of the fibre continuing with the outer connective tissue layer 
(1). The sense of taste depends on the terminal bulbs, which differ 
from the tactile corpuscles in being smaller in size and of simpler 
structure. ( Vide Glosso-pharyngeal Nerve.) 
Fig. 37. 
Fig. 36. 
Diagram of a Terminal Bulb. Diagram of a Terminal Plate 
Fig. 36. 1, Connective tissue layer. 2, Nerve-fibre. 
Fig. 37. 1, Continuation of the nerve-fibre sheath with the sarco- 
lemma. 2, Nerve-tibre, the axis-cylinder of which spreads out and 
forms the terminal plate in the muscular fibre. 
The peripheral cells of nerve-fibre terminals and the cells of the 
nervous centres are two very important factors in nervous operations, 
while the nerve-fibres are simply conductors of the special nervous 
impulses between the peripheral and centre cells, the result being 
determined by the position and character of the terminal cell-organs. 
The external receiving organs are of various kinds, so as to be cap- 
able of appreciating the different kinds of stimulation presented, 
illustrated by those in the eye (cones) receiving the stimuli of light; 
in the ear (organ of Corti), sound; on the tongue (the terminal 
bulbs), taste; in the nose (olfactory membrane), smell; skin, fin- 
ger ends in particular (tactile corpuscles), special touch; and all 
organs (Pacinian bodies), general touch. 
The Terminal Plate (Fig. 37) is found in the muscular fibre. 
A nerve-fibre (2) penetrates the muscular fibre (1) at a right angle. 148 
NERVE-FIBRES AND THEIR TERMINALS. 
Its sheath becomes blended with the sarcolemma, the medullary layer 
disappearing, while the axis-cylinder enters the muscular fibre and 
expands into a terminal plate. ( Vide chapter on Muscular Tissue.) 
Nerve-fibres are the means of communication, connecting the 
nervous centres with the organs of sensation and of motion, and are 
endowed with irritability, by which impulses are transmitted through- 
out their length. The physiological attractive power of a stimulus 
for an impulse produced at the extremity of the nerve-fibre is simi- 
lar to a magnetic bar, having attractive power only at its extremity. 
The physiological irritability of a nerve is that property of becom- 
ing excited by the proper stimulus. Other tissues and organs possess 
a similar property if stimuli adapted to their physiological charac- 
ters be applied. A gland, when stimulated, produces a secreted fluid; 
a muscle contracts, producing a movement of the parts to which it is 
attached. An impulse through a nerve-fibre brings about atomic mo- 
tion (quivering), and, if sufficiently strong or prolonged, causes a 
change of the composition of molecules, and exhaustion in the axis- 
cylinder. This is proven by stimuli frequently applied in the same 
place, the irritabilty being soon weakened or destroyed. Nervous 
as well as muscular irritability becomes exhausted by continuous 
stimulation (excitation), but if at rest for a time their irritability 
will be partially or wholly restored, and if stimulus be applied may 
again become exhausted. The irritability and transmission of im- 
pulses of both sensory and motor nerve-fibres can be diminished or 
totally suspended by cold, compression, contusion, or laceration, if 
the injury is sufficient. After the nervous irritability is restored, 
the power of sensation and motion is re-established. The sensory 
(afferent) fibers transmit impulses inward to the nervous centres; 
the motor (efferent) fibres transmit impulses from the nervous cen- 
tres to peripheral organs. As a rule, both the afferent and efferent 
nerve-fibres are associated in the same nerve and carry impulses in 
opposite directions without interfering with each other in their func- 
tions. No anatomical difference appears to exist between these 
fibres. In some nerves, however, the sensory and motor fibres are 
in separate bundles (nerves), like those of the facial nerve of the 
fifth cranial, being composed of sensory fibres which are distributed 
to the integument of the face and the mucous membrane of the 
■mouth; while the branch of the same nerve distributed to the 
muscles of mastication consists of motor fibres. The fibres of a 
nerve separate near their terminal distribution. 
The irritability of muscular fibres and that of motor nerve-fibres 
is distinct; which is proven by the action of woorara, which destroys 149 
NERVE-FIBRES AND THEIR TERMINALS. 
the irritability of the nerve-fibres without affecting the muscular 
fibres. This accounts for two kinds of paralysis: 1. A nervous par- 
alysis affecting the nerve-fibres only, the muscle being still con- 
tractable by direct stimulus. 2. A muscular paralysis, in which its 
fibres are directly affected, not the nerve. 
The action by which sensory and motor nerve-currents are for- 
warded is very rapid; yet there is a short interregnum, and con- 
sequently it is not instantaneous. In sensation there are three 
successive stages—the reception of an impression by the sensitive 
nerve-terminal, the transmission of the impulse through the nerve- 
fibre, and the vital representation in the organ. ( Vide chapter on 
Senses.) 
The speed of transmission in motor fibres is about from 30 to 32 
metres (about 104 feet) per second; in sensory, from 50 to 60 metres 
(about 196 feet). The transmission of impulses within the spinal 
cord differs very much—tactile impressions, 44 metres (about 144 
feet); painful, 15 metres (about feet); and motor, 12 metres 
(about feet) per second. 
It is an important fact that, should a nerve be divided in any 
part of its course, communication at once ceases, sensation can no 
longer be produced by impressions from without, and no voluntary 
contraction is incited in the muscles. A division of a nerve-fibre, 
or pressure sufficient to separate its axis-cylinder, though its sheath 
may yet remain intact, destroys the transmission of impulses. The 
division of a nerve-fibre, as well as its function, may be restored, if 
both ends at the point of separation remain in apposition; and even 
if a portion of a fibre is destroyed a reproduction of this part may 
take place. If a large nerve is divided, each one of its fibres again 
unites with its fellowq and not with others, so that the function of the 
entire nerve may be restored. The restoration of the normal func- 
tion of a large nerve requires from three months to about two years, 
according to the age and condition of the individual. A division of 
small nerve branches produces a local anaesthesia in the immediate 
neighborhood, which continues for weeks or months after the heal- 
ing of the traumatism. 
Electrically, different actions can be produced by direct and inverse 
galvanic currents. If they traverse the nerve in the natural direc- 
tion of its fibres, from origin towards termination, it is called direct; 
contrary, inverse current. When the nerve is fresh and irritable, or 
when the galvanic current is of sufficient intensity, a muscular con- 
traction takes place at both the commencement and termination of 150 
NERVE-FIBRES AND THEIR TERMINALS. 
the current applied, whether direct or inverse. When exhausted 
by the direct current, the nerve still responds to the inverse; or, 
after exhaustion by the inverse, it still responds to the direct. 
Nothing is so exciting to a nerve as the passage of direct and inverse 
currents alternately in rapid succession. For such electric stimulus, 
we have the faradic apparatus, in which momentary currents of 
induced electricity are made to traverse the circuit in alternate 
directions. (Vide chapter on Nervous Centres and Reflex.) CHAPTER XVI. 
THE SPINAL COLUMN. 
The Spinal Column consists of thirty-three vertebrae, divided 
into seven cervical, twelve dorsal, five lumbar, 
five sacral, and four coccygeal (Fig. 38). The 
vertebrae of the first three divisions are called 
true vertebras, as they articulate, but are de- 
tachable one from another; while the cartilage 
connecting the vertebrae of the last two divi- 
sions becomes ossified, and each division forms 
one bone, and are therefore termed false verte- 
brae. The true vertebrae are joined by elas- 
tic ligaments, and between each is a disc of 
fibro-cartilage acting as a cushion. This, owing 
to its softness and elasticity, prevents jars and 
shocks, and admits of various movements. The 
spinal column is arranged in antero-posterior 
curves, which, according to their position, are 
termed cervical, dorsal, lumbar, and pelvic. 
These curves facilitate the movements of the 
body, protect the spinal cord in the movements 
of the spine, and enable it to bear a greater ver- 
tical weight; so that about ten times greater 
vertical force is required to bend it than if it 
were straight. The dorsal and pelvic curves are 
backward, so as to enlarge the cavities for the 
Fig. 38. 
1, First cervical vertebra, or atlas. 2, Second cervical, or axis. 3, Seventh, 
or last cervical vertebra. 2 to 3, Cervical curve forward. 3 to 4, twelve dorsal 
vertebrae (curve backward). 4 to 5, Five lumbar vertebrae (curve forward). 
6 to 7, Five sacral vertebrae, (the pelvic curve backward). 8, Four coccygeal 
vertebrae. 9, Spinous processes projecting from the vertebrae. 10,10, Foram- 
ina through wdiich the spinal nerve-fibres issue, formed into nerves. 2 to 6, 
Roundish-square projections anteriorly, termed Bodies of the vertebrae. 
Diagram of the spinal column. 152 
THE SPINAL CORD. 
thoracic and pelvic organs. The cervical and lumbar curves and 
the coccyx have a position forward, in order to support the parts 
anterior and above them. 
THE SPINAL CORD. 
The Spinal Cord is a long, cylindrical, nervous mass inclosed 
m the spinal column. It consists of a gray substance in its center, 
surrounded by white matter. In the center of the gray substance is 
the central canal, which commences near the calamus scriptorius in 
the medulla oblongata, and extends downward through the whole 
length of the cord (6, Fig. 26; 
and 8, Fig. 39). 
The internal portion, or gray 
substance, of the cord consists 
of nervous centre-cells and 
nerve-fibrillse; the external, or 
white substance, being com- 
posed of nerve-fibres, arranged 
by two depressions into tracts 
nf three divisions—an anterior, 
lateral, and posterior column 
(5,6, and 7, Fig. 39). The cord 
diminishes as the nerve-fibres 
emerge, so that at the lower end 
it gradually disappears. The 
two halves of the cord are ana- 
tomically continuous, laterally, 
through the nerve-fibres of its 
commissure, and, therefore, act 
only as a single organ. The anterior nerve-roots (4) issue from the 
cells of the gray substance of the anterior horns, and convey im- 
pulses outwardly for the motion of muscles, for secreting and ex- 
creting organs, likewise for vaso-motor, vaso-dilator, and trophic 
functions; while the posterior nerve-roots (3) are connected with the 
posterior horns of gray matter, and convey sensory impulses inward 
to the cord and brain. The cells of the anterior horns (motor) are 
large with multipolar processes; while the cells in the posterior 
horns (sensory) are smaller and spindle-shaped. The nerve-fibres 
of the spinal nerves and the fibres of the sympathetic system free- 
ly communicate with each other in the neck, thorax, and abdomen. 
The spinal nerve-fibres pass from the cord through the interver- 
Fig. 39. 
Diagram of the spinal cord. 
1, Anterior median fissure. 2, Poste- 
rior median fissure. 3, 3, Sensory nerve- 
fibres. 4, 4, Motor nerve-fibres. 5, 5, 
Posterior columns. 6, 6, Lateral col- 
umns. 7, 7, Anterior columns. 8, Cen- 
tral canal. 9, 9, Cerebro-spinal nerve- 
fibres entering to, or issuing from, the 
spinal nervous-centre-cells. THE SPINAL CORD. 
153 
tebral foramina (10, 10, Fig. 38), formed into thirty-one pairs of 
nerves, which are finally distributed to the various parts of the body. 
Eight pairs are cervical; twelve are dorsal; five, lumbar; five, sacral; 
and one coccygeal. Each nerve has two roots—an anterior and a 
posterior root. The anterior root-fibres are motor; the posterior, 
sensory. The latter, before entering the cord, pass through a gan- 
glion (10, 10, Fig. 40) consisting of gray matter with bipolar cells. 
Fig. 40. 
Diagram of spinal nerves. 
1, 1, Posterior horns of the gray matter. 2, 2, Anterior horns of the gray 
matter. 3, Anterior median fissure. 4, Posterior median fissure. 5, 5, Pos- 
terior columns. 6, 6, Anterior columns. 7, 7, Lateral columns. 8, Central 
canal. 9, 9, Sensory nerve-fibres. 10,10, Ganglia on the sensory nerve-fibres. 
11, 11, Motor nerve-fibres. 12,12, Spinal nerves. 13, Pia mater membrane. 
14, Arachnoid membrane. 15, Dura mater membrane. 16, 16, Neurilemma. 
17, 17, Nerve-fibres supplying the muscles and skin of back. 18, 18, Nerve- 
fibres supplying the muscles, skin, and sides of the body. 19,19, Sympathetic 
ganglia . 
The Law of Waller shows that the nutritional activity of a nerve- 
fibre is in the direction of its physiological activity, and that its 
nutrition is influenced by the nerve-cell with which the fibre is con- 
nected. If, therefore, the posterior root (9) be divided between the 
cord and the ganglion (10), the fibres in connection with the gan- 
glion remain unaffected, while the interior ends degenerate. If the 
anterior root (11) of a spinal nerve be divided, in a few days the 
ends of fibres, cut off from the cord, degenerate, while the ends at- 
tached to the cord are still nourished. The effect of this degenera- 
tion on the motor fibres extends through the nerve to its final ter- 
minations. In degeneration of the fibres the medullary substance of 
Schwann (4, Fig. 32) disappears, and the axis-cylinder disintegrates, 
forming drops of fatty matter. 154 
THE SPINAL CORD. 
The brain motor fibres that supply the body and limbs pass from 
one hemisphere to the other at the anterior pyramids of the medul- 
la oblongata, where most of them cross the median line (M, Fig. 
28), to the lateral columns of the spinal cord. Here they enter the 
multipolar cells in the anterior gray horns, which then give off the 
anterior spinal nerve-fibres (motor) (4, Fig. 39; and 11, Fig. 40). 
Some of the brain motor fibres do not cross at the medulla, but pass 
to the anterior pyramidal tract of the medulla, and continue to the 
anterior column of the cord (7, Fig. 39; and 6, Fig. 40), then passing 
to the sympathetic ganglionic cells of trophic (nutritive) centres. 
The impulses through the cerebro-spinal sensory nerve-fibres pass 
from the peripheral organs to the cells of the posterior gray horns 
of the spinal cord (3, Fig. 39; and 9, Fig. 40). From these cells the 
fibres proceed upward to the medulla oblongata, where they cross, 
similarly to the motor fibres (M, Fig. 28), from one side of the cord 
to the opposite side, to the brain centres. On the outside of the 
bony cavity of the spine, the motor and sensory nerve-fibres pro- 
ceed together, coalesced in trunks (nerves), without interfering with 
each other. A spinal nerve is, therefore, made up of sensory and 
motor nerve-fibres, which transmit the impulses necessary for sen- 
sation and motion. 
By this it is proven that the spinal cord is the exclusive organ of 
communication between the brain, the body and limbs. It also 
sends out nerve-fibres from centres of its own, to supply the integu- 
ment and muscles of the neck, trunk, and extremities, and contains 
reflex centres for the sphincter, or constrictor, muscles of the organs 
of evacuation. The small intestines, caecum, and colon are sup- 
plied exclusively with nerves from the abdominal plexus of the 
sympathetic system; while the lower portion of the rectum, mucous 
membrane, and sphincter muscles receive branches from the sacral 
plexus of spinal nerves. The retention and discharge of feces are 
effected by two sets of muscular fibres, which are regulated by re- 
flex influence through the spinal cord. One of these muscles is the 
sphincter ani, which keeps the orifice of the anus closed, while the 
levator ani and circular muscular fibres of the rectum, open it. Any 
external irritation to the sphincter ani increases the contraction of 
its fibres, closing the anus more completely. Its habitual closure is 
entirely involuntary during sleep and in waking hours, depending 
upon the reflex action of the spinal cord; but as soon as the rectum 
is distended to a certain point by feces, the nervous action changes. 
The irritation then produced upon the mucous membrane of the THE SPINAL CORD. 
155 
rectum sends forth an impulse through its sensitive nerve-fibres to 
the spinal cord, which reflexes an impulse of relaxation to the 
sphincter; while, simultaneously, the levator ani draws the borders 
of the relaxed orifice upward and outward, and the feces are ex- 
pelled by the contraction of the muscular fibres of the rectum it- 
self. Resistance to evacuation by the sphincter may be voluntarily 
prolonged; but in time the reflex impulse to evacuate becomes 
so urgent and irresistible that it cannot be controlled by the will, 
and the discharge occurs involuntarily, simply by reflex action of 
the spinal cord. If the lower portion of the cord be disorganized 
by lesion or paralysis, it then loses its power to reflex, and the 
sphincter ani becomes permanently relaxed, and the feces are 
evacuated as fast as they descend into the rectum, without the 
knowledge or control of the patient. 
The supply of blood to the spinal cord is derived from the verte- 
bral arteries, and from branches of the intercostal, lumbar, and 
sacral arteries. At the parts where the greatest number of nerve- 
fibres emanate, the spine is enlarged. Three enlargements espe- 
cially deserve notice—the cervical, dorsal, and lumbar. The cer- 
vical is the principal source of nerves for thoracic organs and re- 
spiratory muscles; the dorsal is the source of nerves for the upper 
extremities, and partly for the thoracic and abdominal organs and 
muscles; while the lumbar enlargement is the principal source of 
nerves for the pelvic organs and the lower extremities. The spinal 
gray matter contains also centres independent of the brain in their 
reflex functions, viz.: 1. A cilio-spinal reflex centre, situated be- 
tween the sixth cervical and third dorsal vertebra); being the nor- 
mal dilating centre of the iris—i. e., for dilatation of the pupil, 2. 
A genito-spinal reflex centre, situated about the middle lumbar re- 
gion of the cord, reflexing impulses to the generative organs; injury 
to this centre is followed by loss of virile power. 3. In the same 
region is the reflex centre for parturition pains in the female. 4. In 
the upper lumbar region are the ano-spinal and vesicospinal centres, 
reflexing motor impulses to the sphincter ani and the sphinter 
vesicse. Loss of reflex at these two centres causes involuntary 
evacuation of the rectum and complete paralysis of the bladder, 
the urine constantly escaping in dribblets, though the bladder 
may remain partially filled. 
Section of the cord between the third and fourth cervical ver- 
tebrie paralyzes the phrenic nerve and arrests the action of the dia- 
phragm; section between the fifth and seventh paralyzes the 156 
THE SPINAL CORD. 
posterior thoracic nerve and thoracic muscles; section from the 
first to the ninth dorsal paralyzes the intercostal muscles; section 
from the seventh to the twelfth dorsal, the abdominal muscles. 
The spinal cord has principally a three-fold function: 1. It serves 
as a medium for conducting impulses through nerve-fibres from the 
brain to the peripheral organs, and vice versa. 2. In the normal 
condition many spinal centres are subservient to centres in the 
brain, so that the cord reflexes may be inhibited or restrained, 
more or less, especially over movements by spinal-reflex on parts 
that can be moved by the will. 3. In case the reflex action of the 
cord be on a portion of the body which is invariably involuntary, 
then such action cannot be inhibited by the will. This is illustrated 
by the cilio-spinal centre, acting on the iris, dilating the pupil; by 
the parturition centre, acting on the uterus during labor pains. If 
the spine be separated from the brain, some centres in the cord 
are still capable of action, such as those which by reflex effect 
the closure and dilatation of the sphincter muscles, and muscular 
contraction, showing a powrer of reflex action by the cord independ- 
ent of the brain. 
The Urinary Bladder is both a reservoir and an organ of 
evacuation. It is protected at the commencement of the urethra 
by a circular bundle of muscular fibres, known as the sphincter 
vesicse, and is supplied by nerve-fibres from the hypogastric and 
sacral plexuses. Those from the hypogastric are distributed to the 
upper part of the necx of the bladder; those from the sacral, to the 
lower part. The tonic contraction of the vesical sphincter during 
health is continuous and involuntary, like that of the sphincter 
ani. When micturition occurs the sphincter vesicse relaxes, while 
the muscular coat of the bladder contracts to expel its contents. A 
relaxation of this sphincter may also take place by voluntary im- 
pulse, acting on the spinal reflex centre of micturition; but the sub- 
sequent contraction of the bladder continues without voluntary ef- 
fort. Lesion of the hypogastric plexus may paralyze the upper part 
of the neck and bladder; lesion of the sacral plexus may paralyze 
the lower part. The principal reflex impulse for contraction of the 
bladder emanates from the spinal cord through the sacral nerves. 
In inflammation of the bladder, or neighboring parts, its sensitive- 
ness is increased, and the reflex impulse to urinate cannot be re- 
sisted. Increased acidity of the urine produces a similar result. 
Paralysis of the bladder causes its permanent distension, followed 
by a continuous, passive, but incomplete, discharge. THE SPINAL CORD. 
157 
Normally, the reflex actions of the spinal cord are chiefly of an 
expulsive kind — to force out the contents of the various cavities, 
such as defecation and urination, ejaculatio seminis, and parturi- 
tion, over some of which the will has very little or no control. 
The decussation, or crossing, of both motor and sensory nerve- 
fibre tracts is at the medulla oblongata. A lesion in a certain por- 
tion in a lateral half of the brain above the medulla oblongata 
causes paralysis on the opposite side of the body; but if the lesion 
is below the medulla oblongata on the lateral half of the spinal cord, 
then the paralysis is on the same side of the body. Paralysis of 
one-half of the body is termed hemiplegia. A lesion involving the 
middle or upper entire portion of the cord transversely, induces a 
paralysis called paraplegia, or palsy transversely; i. e., paralyzing 
legs and thighs and lower part of body, including the bladder and 
rectum. The communication between them and the brain being ar- 
rested, sensation is no longer experienced in said parts, nor can the 
will produce contraction of muscles below the lesion. The seat of 
lesion in any part of the spinal cord is determined by the line at 
which paralysis of sensation, motion, or both, manifest themselves 
in the external parts—if in the lumbar portion, then the legs and 
pelvic region are paralyzed; if in the dorsal, all below the thorax 
and abdomen; and if in the middle cervical region, then both the 
upper and lower extremities, chest, and intercostal muscles. A 
lesion, injury, or disease, though very slight, if just above the middle 
cervical part of the cord, is a dangerous affair, because it cuts off 
the reflex motor impulses to the respiratory muscles, producing 
death by stopping respiration. The phrenic nerve arises at the 
third, fourth, and fifth cervical, and supplies the diaphragm. 
The physiological effect of strychnine is directly upon the cord, 
producing rapid irritation, and augmenting its excitability for reflex 
action, so that the slightest external stimulus causes excessive mus- 
cular action and convulsive movements. A wound affecting periph- 
eral nerves may produce tetanic spasms or convulsive actions by 
reflex of the cord, and when the increased irritability of the cord is 
once established, it is easily excited by an external cause, which 
may be so slight that a healthy person would not perceive it. Dur- 
ing such an affection, startling movements or sounds of any kind, 
or even a current of air upon the skin may, by reflex of the cord, 
throw the muscular system into severe spasmodic action. The spi- 
nal cord as a nervous centre is apparent in such convulsive diseases 
as hydrophobia and tetanus, over which the will has little influence. 158 
THE SPINAL CORD. 
In Hydrophobia, not only the spinal cord, but the medulla ob- 
longata and some of the cerebral ganglia, are involved. The effect 
is brought about by blood-poisoning; but, strangely enough, the 
rest of the brain completely escapes its influences. The stimulus 
most effective in hydrophobic convulsions is through either one or 
both of twrn senses—the sight or sound of water causing a paroxysm, 
and any attempt to taste it increasing the severity. 
In Tetanus there is a similar excitable state of the spinal cord 
and medulla oblongata, but it does not involve the ganglia of any 
of the five external senses, except that of touch. The cause of tet- 
anus may be altogether internal, as in the idiopathic form—a con- 
dition resembling that which may be artificially induced by strych- 
nine. It may also arise from traumatism, as a lacerated wound, 
the irritation of the peripheral injured nerve terminal being prop- 
agated to nervous centres, establishing the excitable condition; and, 
once established, the removal of the original cause by amputating 
the injured limb seldom does any more good, because the slightest 
impression upon almost any part of the body is sufficient to excite 
the tetanic spasm. 
Epilepsy, or convulsive movements with temporary suspension 
of the functions of the cerebrum, generally results from internal or- 
ganic functional derangement, which, when established, causes also 
an excitable condition and disorder of the nervous centres. It may 
result from irritation proceeding from local causes, like the convol- 
sions of teething, and cease Avhen the irritation is removed. 
Convulsions which end fatally usually act by suspending the re- 
spiratory movements, the muscles which effect respiration becoming 
fixed by the spasms, so that suffocation occurs as completely as if 
the air passages ivere ligated. 
Hysteria is a peculiarly excitable state, in which every kind of 
convulsion may be simulated, although there is seldom present a suf- 
ficient indication of any positive disease. One form of convulsion 
after another often occurs at short intervals, and with wonderful 
variety. Hysteria may be likened to convulsions from local irrita- 
tion, such as hysteric spasms at the catamenial period, especially if 
menstrual flux be deficient. A diagnostic feature distinguishing 
hysteric from epileptic convulsions is that in the former the patient 
does not bite the tongue, the centre at which the hypoglossal nerve- 
fibres originate seemingly remaining unaffected. 
The membranes covering the brain and spinal cord are termed 
meninges, and an inflammation thereof meningitis, which, if on the THE SPINAL CORD. 
159 
posterior portion of the cord, causes great pain; if on the anterior 
portion, however, convulsive movements without pain ensue. Usual- 
ly the morbid action extends to the anterior and posterior mem- 
branes and columns, thereby causing severe pain and disturbing 
motion. CHAPTER XVII. 
THE SYMPATHETIC SYSTEM. 
The Sympathetic Nervous System consists of ganglia of 
gray matter (forming nervous centres), and slender nerve-fibrillae 
issuing therefrom. It is not an entirely independent system. Its 
ganglia are not only connected with each other, but also communi- 
cate with the cerebro-spinal system by nerve-fibrillae. Along each 
side of the spinal column the ganglia lie in the form of a chain-like 
continuation, though in other parts of the body they are scattered 
irregularly. A Ganglion is a discrete encapsulated portion of 
gray matter in the course of, and ccnnected with, nerve-fibres, as 
the Gasserian ganglion of the fifth nerve, or the Otic (Arnold’s) 
ganglion below the foramen ovale. Each ganglion contains nervous 
'centre-cells with multipolar processes (C, Fig. 30). The nerve- 
fibrillae issuing therefrom freely intercommunicate with each other 
and with the chief ganglia, and are of two kinds—medullated 
and non-medullated. The medullated are derived from the cerebro- 
spinal system, and pass through the sympathetic ganglia, supply- 
ing the vascular and secreting organs. The non-medullated fibres 
are destitute of the white substance of Schwann. They consist of 
a gray, gelatinous substance, and originate in the sympathetic 
ganglia. Through these fibres, sensory or motor, the sympathetic 
impulses are transmitted, thereby establishing that sympathy, 
greater or less, existing between all organs of the body. Its nerve- 
fibrillse are distributed to the walls of the blood and lymphatic 
vessels, interlacing them as ivy entwines the tree. They accompany 
these vessels throughout their ramifications and to their utmost 
terminations. They are also distributed to the organs of the head, 
neck, trunk, and extremities. 
The more delicate nervous centres of the brain and spinal cord 
are wonderfully protected from over-irritation. This protection 
lies in the modifying power of the sympathetic ganglia placed on 
the tract of sensory nerve-fibres of each spinal nerve (1,1, Fig. 41). 
The sensory fibres to the cerebral convolutions pass through the 
•optic thalamus (D, Fig. 28). 161 
THE SYMPATHETIC SYSTEM. 
The sympathetic nervous system is most largely distributed with- 
in the chest and abdomen, connecting the organs of nutrition, such 
as the secretory, digestory, absorbent, and the circulatory appara- 
Fig. 41. 
Diagram of the sympathetic system, 
1, Ganglia on sensory nerve-roots of right side of spinal column. 2, Gas- 
serian ganglion. 3, Otic ganglion. 4, Ophthalmic ganglion. 5, Spheno- 
palatine ganglion. 6, Submaxillary ganglion. 7, Deep cardiac plexus. 
8, Superficial cardiac plexus. 9, Semilunar-ganglion plexus. 10, Renal 
plexus. 11, Aortic plexus. 12, Epigastric or Solar plexus. 13, Spermatic 
plexus. 14, Hypogastric plexus. 
tuses. It also presides over the functions of the internal organs. Be- 
sides its many ganglia of varying sizes, it forms more than fifty 
nervous plexuses, such as the aortic, cardiac, cervical, epigastric, 162 
THE SYMPATHETIC SYSTEM. 
hepatic, hypogastric, lumbar, pulmonary, renal, sacral, solar, sper- 
matic, and many others. 
The peristaltic action of the oesophagus, stomach, and intestines 
is by reflex, through the motor fibres, from the nervous centres in 
the medulla oblongata. The vaso-motor centres of the medulla 
reflex impulses for dilatation and contraction to the vascular sys- 
tem, in a similar manner. These nerve-fibres pass out through the 
spinal foramina with the spinal nerves (Fig. 41), but soon leave 
them to enter sympathetic ganglia (19, Fig. 40). This accounts for 
the harmonious co-ordination of functions of the medulla oblongata 
with those of the sympathetic system and of the organs of the body. 
The peculiarity of the sympathetic nervous system is the small 
diameter of its nerve-fibres and the difference in function from 
that of the cerebro-spinal system. The latter system manifests its 
most striking properties in sensation and motion; while the former 
preponderates in regulating the proper performance of the func- 
tions of co-ordination of the organs of digestion, absorption, assim- 
ilation, circulation, and growth. The nerve-fibres of the sympa- 
thetic are also distributed to internal organs, glands, mucous mem- 
branes and their internal muscular fibres, such as are not controlled 
by the will. 
Physiologically, the sympathetic nervous centres, or ganglia, are 
endowed with sensitiveness and the power of conducting, reflecting, 
augmenting, and inhibiting impulses. The ganglia of the sympa- 
thetic system are sensitive to impressions, and are capable of per- 
ceiving irritations, which may even give rise to acute pain. The 
reflex action, which causes the pupil of the eye to contract or ex- 
pand owing to variation of light, is propagated through the oph- 
thalmic ganglion; therefore, the iris acting somewhat sluggishly, 
indicates the intervention of the sympathetic system, which in all 
instances requires more continued stimulation and is less rapid in 
activity, but of longer duration, than those of the cerebro-spinal 
system. CHAPTER XVIII. 
THE SENSES. 
A Sense is the capacity or power of the animal for a particular 
species of what are termed sensations. The special portions of the 
organism endowed with the simple power of reacting to appropriate 
stimuli so as to produce these particular groups of sensations, are 
called Sense-organs. Sense, therefore, is an organic faculty, or 
one that pertains not to the living vital principle (soul*) alone, 
but to the composite, or that which is made up of soul and matter 
conjoined. As sensation is the proper operation of the animal inas- 
much as it is animal, and as the animal is not soul alone, but 
a compound of body and soul, so the faculty of sense pertains to 
the composite, and is an organic faculty. Sensation is in itself sim- 
ple, for there is no one who does not see that a sensation, considered 
as such, cannot be divided. We have said “as such”; for, although 
the animal under certain circumstances may have only a portion 
of the sensibility it once enjoyed, on account of the material organ, 
yet that which it now has considered as sensation cannot be divided. 
In the sensation itself, however, we can distinguish the formal ele- 
ment from the material one: viz., the vital representation and the 
nerve vibrations, which latter element is extended and divisible. 
Sensation, therefore, is in itself simple, unextended, and indivisible, 
but, considered in reference to the organ and nerve vibrations, 
extended and divisible. 
Sight, Hearing, Smell, Taste, and Touch constitute the 
five external senses, by and through which the perfect animal becomes 
cognizant of external objects, of their physical appearance, qual- 
ities, quantity, etc., while at the same time it is endowed with four 
internal senses—the common sense, imagination, estimative faculty or 
instinct, and sensitive memory. As to the existence and reality of 
the five external senses, no one can reasonably call them in ques- 
tion; but as to the four internal, equally undeniable though they 
be, yet unaccustomed as we are to hear them even mentioned, or 
if we do, to hear them spoken of in reference to man alone, and 
then often either considered as powers belonging only to the mind, 
* See Note, page 129. 164 
THE SENSES. 
or else some of them, such as the sensitive memory and the com- 
mon sense, confounded with the inorganic faculties of intellectual 
memory the understanding, it will not be out of place here to lay 
down a few clear notions on this point. We will take each of the 
internal senses in order, give an idea of its nature, and the proof of 
its existence, together with necessary remarks: 
I. The Common Sense.—Every one has experienced that he 
not only perceives external objects proper of each of the external 
senses, but also feels the very sensations themselves as they are per- 
fected in the external organs, and between them to discriminate one 
from the other. In other words, he not only perceives, or “senses” 
exterior objects by the external senses, but also feels the very acts 
by which they are perceived or “sensed,” and distinguishes between 
them. Now, this cannot be done by the external senses, as these 
perceive only those objects proper of them. There is need, then, of 
some faculty pertaining to and not above the order of sensibility, 
which perceives these external sensations and discriminates be- 
tween them. Thus, for instance, we distinguish a white thing from 
a sweet thing, and the sensation of whiteness from the sensation of 
sweetness; but as the sense of sight and the sense of taste (which are 
the senses here concerned) know only their own proper objects, it 
follows that there must be some other sense which perceives and 
distinguishes between them. If it be said that the intellect does 
this, it is answered that the same thing happens in the brute ani- 
mal, which has no intellect. Is it not according to experience that 
a dog or a horse, for instance, raises its ears to hear better, thus 
showing that it feels the very external sensation itself? Are not 
animals sometimes so affected by music as to give full evidence of 
it by cries and other signs? Again, who can deny that the brute 
animal feels that it sees, feels that it tastes, feels that it smells? Now, 
the eye cannot distinguish between color and taste, the tongue can- 
not distinguish between taste and smell. The same likewise dis- 
tinguishes between the objects of the different senses. Thus, a dog 
seeing an object at a distance which appears to its sight as a piece 
of meat (a painting), on approaching and smelling the same quick- 
ly rejects it. There must then be an organic faculty which receives, 
feels, and distinguishes all these impressions with the objects (stim- 
uli) that excite them, and this faculty is called the common sense, or 
by some the internal sense. That the animal has not understanding, 
and therefore no intellect, is admitted by every one of real philo- 
sophic acumen. The discrimination, be it remarked, which is spok- THE SENSES. 
165 
en of above, must not be confounded with judgment properly so 
called, for it is nothing more than a true though sensible apprecia- 
tion of external sensations by means of the common sense. This 
operation of the common sense, in reference to external sensations, 
is sometimes called conscience, the proper meaning of which we 
will speak of in its proper place. 
Having shown that the brute animal as well as man possesses 
the internal or common sense, and supposing here that in the brute 
animal there is no faculty that goes beyond the purely organic, it 
clearly follows that this common sense must be a faculty operating 
through an organ, laying aside all controversy as to this organ’s 
location, and contenting ourselves with having shown the necessity 
of its existence. In like manner it clearly follows that, if in the 
sequel it can be shown that the perfect animal possesses the other 
three internal faculties above mentioned, namely the imagination, 
the estimative faculty, and sensitive memory, we have at the same 
time shown the existence of three other internal organs. 
Before coming to the imagination, which is the second internal 
faculty in the order of nature, we will add something on external 
and internal sensation, and on conscience, for the better understand- 
ing of what has been already said. We have spoken of external 
sensations, which implies that there are also internal sensations. 
If sensation is defined, as it truly is, a vital organic representation, it 
is very evident from the very definition of sensation that, since there 
is at least one internal sense, as we have just now shown, and that 
this sense requires an organ, there must be internal as well as exter- 
nal organs quite distinct among themselves, and a dependency of 
the former on the latter. This dependency and connection is 
proved both by experience and by the very object of the internal 
sense as stated above. There is a great mistake made by some in 
supposing that external sensation—for instance, that of sight—is 
produced in the brain. This error arises from the circumstance of 
finding in the case of the eye (and what is said of the eye is equal- 
ly true of the other external senses) a sensory nervous centre in 
the brain, with which the optic organ is connected. Now, the case 
is far otherwise, for it is according to experience that we see with 
the eye, hear with the ear, etc., and not with the brain. Sensation, 
therefore, if experience is to stand, takes place in the organs them- 
selves. A pain in the foot is really there, and not in the brain. Be- 
sides, if the sensation of hearing, for instance, is in the brain, why 
is the ear so wonderfully formed, since a simple system of nerves 166 
THE SENSES. 
would suffice for transmitting the impression made by the sound- 
ing body to the brain. The same can be said of the other sense- 
organs. This opinion, holding sensation to be produced in the 
brain, comes often from the false supposition that the soul (vital 
principle) does not reside in the whole body but in the brain only. 
How erroneous such an opinion is, will be rendered clear if we 
keep in mind that the soul is the principle of life and must be pres- 
ent by its essence wherever there is life and vital power. Now, 
there is certainly life and vital power, not only in the whole body, 
but in each single part of it. Therefore, the soul must be present by 
essence, not only to the whole body, but to each single part of 
it. If it be objected that, having destroyed communication be- 
tween the external organ and the brain, sensation is destroyed, 
and consequently that sensation is produced in the brain, the 
objection may be answered thus: 1. That, having destroyed the 
organ, sensation also is destroyed, and therefore, sensation is 
produced in the organ. 2. The necessity of nervous centres in 
the brain is not denied, for it is according to the most common 
physiological experience that, separated from these centres, the 
organs are inadequate to the production of sensations. That 
exterior sensations, however, are produced in the brain is denied. 
As the common sense is a faculty which is concerned with what 
is popularly termed consciousness, it is proper to state in this 
place what is strictly meant by the consciousness of a sensation, 
which even the brute animal possesses in common with man. 
Consciousness, ‘psychologically considered, is properly and strictly 
defined as that power of the rational soul of returning com- 
pletely upon itself, by which the intellect not only perceives the 
acts of the other faculties but its own acts also, and recog- 
nizes itself as the subject of them. Now, the reason why the 
rational soul alone, which is of man, has such a capability, 
is because of the inorganic nature of that act, which is in 
itself independent of matter and performed without the in- 
strumentality of any organ. Hence to a principle, which 
although simple in itself is yet essentially dependent on mat- 
ter and cannot act but conjointly with an extended organ as is 
the brute soul, this complete return on itself cannot take place on 
account of that matter to which it is united being extended and its 
parts consequently existing one out of the other. This term con- 
sciousness is properly and strictly applied only to certain intellect- 
ual acts of the rational soul, and does not pertain to the order of 
sensibility. As, however, there is no other English word so well THE SENSES. 
167 
adapted to convey the meaning of that operation by which the 
common sense takes cognizance of, and appreciates external sensa- 
tions, we can by giving notice of the fact so as to preclude all mis- 
apprehension, apply the term to this act also. 
II. The Imagination is the faculty of representing corporeal 
things that are absent. This is to be understood in the sense, that 
the operation of this faculty does not represent its object inasmuch 
as it is really present, and not in the sense that it does not operate 
except in the absence of the object; for in every impression of a sen- 
sible exterior object on our senses, as, for instance, an object of 
sight, both the act of vision of that object, and the act of the im- 
agination of the same object, are brought into play at one and the 
same time. To prove this fully would detain us much too long, 
and involve much metaphysical reasoning. Suffice it to say, that 
the acts of the intellect while the human soul is united with the 
body, are always accompanied by an act of the imagination—a thing 
which is confirmed by experience. The imagination is a faculty 
not only for representing objects of the sight that are absent, but 
also for representing objects of the other external senses also in 
their absence. This is true, likewise, in regard to the objects of the 
common sense which it also reproduces in their absence. Thus, after 
having seen a beautiful picture, we can in the quiet of our room 
conjure up its representation. Having listened to some delightful 
music, we can in like manner enjoy it again in its absence. Dreams 
also take their rise and are seated in this faculty of imagination, 
which, when we are asleep, brings before us a representation of 
things that may be long since past. Now, no one can deny this 
power to man; and yet the brute animal, too, has this same power, 
but not in so high or excellent a degree as man, on account of the 
union and connection of this faculty with man’s intellect. To show 
that animals possess this faculty of imagination, does not the cat, 
for instance, on hearing the sound of mice go in search of them, 
their phantasm in him being awakened by the sound it now hears? 
Again, do not dogs, cows, and horses give evident signs that they 
sometimes dream? 
This faculty, according to what we have laid down above, is 
organic; and consequently, its organ, since it is not found among 
the external, must be found among the internal organs. 
III. The Estimative Faculty is a sense endowed with the pow- 
er of estimating or valuing objects as good or hurtful for appetite, 
or of apprehending an object as fit or unfit for the needs of animal 168 
THE SENSES. 
life. This is the power often called instinct. Thus the chicken 
flees from the hawk, and the sheep from the wolf; not because the 
hawk or wolf has anything repulsive in outward appearance, 
since they do not flee from much more repulsive-looking animals. 
It cannot, moreover, be owing to anything the chicken or the sheep 
has learned by experience, for even the young chicken and the 
lamb, although they never saw either hawk or wolf, will flee from 
them at first sight; the chicken from the hawk, and the lamb from 
the wolf. Again, the dog goes in search of grass in time of sickness, 
having the instinct of its fitness for nature at that particular time. 
This power is organic from what has been said above, and its organ 
is internal. The same power is found also in man, which, however, 
on account of its higher grade in him is called cogitative power. 
IV. The Sensitive Memory is a faculty of the perfect ani- 
mal for retaining those things apprehended by the sensitive faculty. 
Thus, a horse remembers the stable on account of the food which it 
receives there, and the dog the stick with which it was struck, on 
account of the pain. This goes to show that this memory is of 
things apprehended as agreeable or unpleasant, useful or hurtful to 
nature, and therefore of things as we have said, apprehended by the 
estimative faculty. This faculty is found in man; but on account of 
its conjunction with the intellective soul is called reminiscence. It 
must be organic from what has been said, and its organ internal. 
Having given, as we think, a sufficiently clear account of the in- 
ternal senses as we proposed to do, we come now to an explanation 
of the terms used in defining sensation, to the elements of sensation 
and the different sciences under which each of these elements fall. 
Sensation, as we defined it above, namely, in the proper philo- 
sophical sense, is vital, organic representation. It is vital, in contra- 
distinction to representations merely physical, which, for instance, 
happen in the impression of the image of an object on the retina of 
the eye; for whether the animal be dead or alive, this image is 
equally impressed. It is organic, in contradistinction to those rep- 
resentations produced without the intrumentality of organs, such 
as the intellectual or mental ones. Sensation, therefore, comprehends 
in its essence three distinct elements: the object, the organ, and the 
vital principle. On the part of the object, an immediate action on 
the faculty through the organ, by the physical outward world in 
the case of external, and a mediate one in the case of internal sen- 
sations, is required; the investigation of the nature of which con- 
stitutes the object of physics and metaphysics. The investigation of THE SENSES. 
169 
the material character of the process -within the organism, which 
goes before, accompanies, and follows the vital representation, or as 
they now say of the function of the organ of sensation, makes up 
the subject-matter of physiology, while the investigation of the sen- 
sitive faculty and operation itself belongs to psychology. With the 
first of these we have nothing to do here, and therefore relegate it 
to its proper domain. The third element we leave to the psycholo- 
gist, and reserve the second for ourselves, in so far as external sen- 
sation alone is concerned. 
A nervous apparatus is simply a nerve-fibre which connects 
two cells. Consequently, for effecting the merely material action 
within the organism three structures are necessary: a peripheral 
end organ, a sensory nerve-fibre, and a nervous centre-cell. The pe- 
ripheral end organ receives stimuli, which, acting on the sensitive 
faculty through its organ, connected by the sensory nerve-fibre with 
the center-cell in the cerebrum, produce the vital external represent- 
ation (sensation). The different senses, as said before, require spec- 
ial nerve centres of sensory areas in the cerebrum though these are 
not the very organs of exterior sensations as we have before shown. 
Thus sight requires a centre in the occipital lobe; hearing, one in 
the temporo-sphenoidal gyrus; smell, one in the lower portion of 
the temporal lobe; taste, one near that of smell; touch, one in 
areas of the limbic lobe, i. e., convolutions surrounding the corpus 
callosum such as the gyrus fornicatus, and gyri hippocampi. 
Increased capillary circulation of the brain may cause illusions 
of sensation, such as of seeing, smelling, or hearing objects not pres- 
ent, etc. Impressions on some of the sense-organs remain for a 
time, even after the cause is removed. The organs, after continued 
impressions, become accustomed to them unless the impression be 
increased, diminished, or locally changed. (See Olfactory, and 
Glosso-pharyngeal Nerves.) The normal stimulus on a sense-organ 
has its limit: if too weak there is no action; if too strong, pain. 
For the sensation of touch, see tactile corpuscles and Pacinian 
bodies; for taste, the terminal bulb, and glosso-pharyngeal nerve; 
for smell, the olfactory nerve; for sight, the eye; for hearing, the ear. CHAPTER XIX. 
CRANIAL NERVES. 
The Cranial Nerves, consisting of twelve pairs, are a part of 
the cerebro-spinal system, all having their origin in the gray sub- 
stance of the brain, though the spinal accessory partly arises at the 
spinal Cord. These nerves are usually enumerated, beginning at the 
anterior part of the cranium to the posterior (Fig. 29 ), in the 
following order: 
First—Olfactory. 
Second—Optic. 
Third—Oculomotorius (Motor oculi). 
Fourth—Trochlearis. 
Fifth—Trigeminus. 
Sixth—Abducens. 
Seventh—Facial (Portio dura). 
Eighth—Auditory (Portio mollis). 
Ninth—Glosso-pharyngeal. 
Tenth—Pneumogastric. 
Eleventh—Spinal accessory. 
Twelfth—Hypoglossal. 
The cranial nerves may be classified as sensory, motor, and 
mixed. 
The Sensory are the olfactory, optic, lingual or gustatory 
branch of the trigeminus, auditory, and a part also of the glosso- 
pharyngeal. 
The Motor are the oculomotorius (motor oculi), trochlearis, 
abducens, facial, and hypoglossal. 
The Mixed (sensory and motor) are the trigeminus, glosso- 
pharyngeal, pneumogastric, and spinal accessory. 
In the medulla oblongata and pons Varolii, the nervous centre- 
cells giving origin to motor fibres are situated anteriorly, and on 
the median line; while the cells of the sensory fibres are located 
further inward and posteriorly, similar to the centre-cells of the 
motor and sensory fibres of the spinal cord, situated anteriorly and 
posteriorly, respectively. CRANIAL NERVES. 
171 
The Olfactory Nerve carries material impulses for the sense 
of smell. It originates in three roots: the external, middle, and 
internal. The external 
root arises from cells of a 
nucleus of gray matter in 
the tern p o r o - sphenoidal 
lobe in front of the pes 
hippocampi. The middle 
root arises from the cor- 
pus striatum, and from a 
papilla of gray matter 
termed caruncula mam- 
milaris. The internal root 
arises from the gyrus for- 
nicatus in the anterior 
lobe. The fibres of the ol- 
factory nerve form a tract 
which enters a lump of 
gray matter termed the ol- 
factory bulb, resting on the 
cribriform plate of the eth- 
moid bone. From the ol- 
factory bulb issue about 
fifteen filaments, passing 
through as many foramina (11 ) in the cribriform plate of said 
bone, and terminate in the olfactory or Schneiderian membrane, 
which is distributed through the mucous membrane of the nose. 
The originating centres of the olfactory nerve-fibres of both hem- 
ispheres are in communication with each other by nerve-fibrillse. 
FIRST PAIR OF CRANIAL NERVES—THE OLFACTORY, 
Fig. 42. 
Diagram of the olfactory nerve. 
A, Cerebrum. B, Cerebellum. 
1, Internal root of olfactory nerve. 2, Ex- 
ternal root. 3, Middle root. 4, Corpus stri- 
atum. 8, Pons Yarolii. 9, Medulla oblong- 
ata. 10, Olfactory bulb. 11, Cribriform plate 
of the ethmoid bone. 12, Schneiderian mem- 
brane. 
The olfactory nerve differs from other nerves in containing soft 
and pulpy gray matter, its fibres being non-medullated. The size 
of the olfactory bulb enhances the function of smell; being com- 
paratively large in dogs, cats, and bees, whose sense of smell is 
more acute. Humboldt states that the Peruvian Indians are able, 
in the darkness of night, to distinguish by smell whether an ap- 
proaching stranger be a European, an American Indian, or a Negro. 
Congenital absence or disease of the olfactory bulb impairs the 
ability and capacity to distinguish odors. A necessary condition 
for smell is that the mucous membrane of the nose be moist, and 
that the odorous be in the form of gases or fine powder, 172 
CRANIAL NERVES. 
and the air kept in motion by inhalation and exhalation to excite 
the nerve terminals. When said membrane is dry the sense of 
smell is either impaired or lost. Thus, in the first stage of catarrh 
there is little or no secretion of moisture (mucus) in the nostrils. 
Interruption of respiration prevents smell, while rapid inspirations 
and dilation of the nostrils increase and intensify it. The stim- 
ulus must come in contact with the Schneiderian membrane by in- 
halation. If a fluid or solid substance be applied directly to this 
membrane, the odor of such a substance is very slightly or not at 
all perceptible. The olfactory organs become accustomed to odors, 
and consequently it requires variation of external stimulus to pro- 
duce impressions. The nasal membrane, through nasal branches 
of the first and second division of the fifth cranial nerve, is sensi- 
tive to cold, heat, itching, tickling, and pain. That these nerves 
cannot perform the function of the olfactory is proven by the fact 
that when smell is lost the membrane of the nose still remains sen- 
sitive to the above-mentioned sensations, all of which, however, are 
but modifications of the one sense of touch. The sense of smell va- 
ries in different individuals; odors pleasant to some being offensive 
to others. Even illusions may occasionally occur wrhen an odor is 
merely imagined, but not real. The centre of smell of the external 
root (2) and that of taste are placed near together at the bottom 
of the fissure of Sylvius. 
The Optic Nerve (one from each cerebral hemisphere) origin- 
ates principally in the anterior portion of the corpora quadrigem- 
ina, with a few fibres from the posterior part of the optic thala- 
mus and corpora geniculata (Fig. 43). The fibres pass inwardly 
forward from one side of the cerebrum towards the other, forming 
the two optic tracts, which meet upon the median line, wh°re they 
cross each other (decussate), forming the optic commissure, or chi- 
asma (2, Fig. 29). They then diverge, forming the optic nerves 
proper, which leave the cranium through the optic foramina and en- 
ter the orbits. At the posterior aspect of the eyeball, the nerve, pierc- 
ing the sclerotic and choroid coats, terminates in a nervous expansion 
called the retina. At the decussation, each optic nerve incorporates 
with its own fibres a few from the origin of the opposite hemisphere; 
and each nerve is, consequently, in communication with both hemi- 
spheres. The optic nerve is remarkable in this, that its fibres run 
a longer course within than without the cranium, and furnish 
SECOND PAIR OF CRANIAL NERVES—THE OPTIC. CRANIAL NERVES. 
173 
no branch from the origin (decussation) to the termination. Its 
surrounding neurilemma is derived from the dura mater. The de- 
cussation of the nerves facilitates the harmonious control of the 
two eyes, so that the light- 
rays on the retina of a 
single object transmit an 
impulse through the optic 
nerve of each eye to the 
cerebral centre of sight. 
Physiologically, the optic 
nerve carries the impulse 
of stimulus for the comple- 
tion of the sense of sight. 
We have said completion, 
since it requires three or- 
gans—the eye, the nerve, 
and the nervous centre. 
Normally, the rods and 
cones of the retina receive 
the stimulus of vibrations 
of light-ether. The impres- 
sion thus produced by the 
luminous rays upon the 
retina causes the sensation 
of sight as long as the ret- 
ina is connected with the 
nervous centre by the optic 
nerve. Section of the optic 
nerve is not painful, but 
produces blindness immediately in the eye affected, since impres- 
sions received by the retina are no longer transmitted to the cere- 
bral centres. The partial blindness of both eyes is sometimes ob- 
served in hemiplegia, in which probably the transmission of light 
becomes defective through both the crossed and direct fibres of the 
optic tracts. A stimulus applied to one eye may cause contraction 
of the pupils of both eyes, because sensitive impressions on the 
retina, conveyed only by one optic nerve to the nervous centre of 
sight in the cerebrum, are transformed into motor impulses, and 
by reflex from the centre of sight sent to the iris simultaneously 
through both of the oculomotorius nerves. (Vide Eye and Sight.) 
Fig. 43 
Diagram of the Optic Nerve. 
A, Middle lobe of the cerebrum. B, Cere- 
bellum. C, Optic nerve. D, Conscious sen- 
sation centre, or cerebral area of sight, in 
the posterior cerebral lobe. 
1, Corpus striatum. 2, Optic thalamus. 
3, Corpora quadrigemina. 4, Corpora genic- 
ulata. 5, Crus cerebri. 6, Pons Varolii. 
7, Medulla oblongata. 174 
CRANIAL NERVES. 
THIRD PAIR OF CRANIAL NERVES THE OCULOMOTORIUS. 
The Oculomotorius, or Motor Oculi nerve, carries impulses 
of voluntary motion to the levator palpebrse, to the superior, inter- 
nal, and inferior recti, and 
inferior oblique muscles of 
the eye; i. e., it supplies 
four out of the six muscles 
that move the eyeball. Its 
fibres originate from the 
valve of Vieussens, situated 
between the third and the 
fourth ventricles, and some 
fibres are traceable to the 
corpora quadrigemina, crus 
cerebri, and the floor of the 
fourth ventricle. The fibres 
aggregate and pass to the 
orbit through the sphenoid- 
al fissure, between the two 
heads of the external rec- 
tus muscle. The physiolog- 
ical properties of the oculo- 
motorius nerve are to car- 
ry exclusively motor im- 
pulses to the upper eyelid, 
and for the vertical, lateral, 
and rotary movements of 
the eyeball, but contractile 
for the iris and ciliary muscles. In paralysis of this nerve there is 
drooping of the eyelid (ptosis), external strabismus, and dilatation 
of the pupil. ( Vide Eye and Sight.) 
Fig. 44. 
Diagram of the oculomotorius, or mo- 
tor oculi, nerve. 
A, Cerebrum. B, Cerebellum. C, Oculo- 
motorius nerve. 
1, Corpus striatum. 2, Optic thalamus. 
3, Corpus quadrigeminus. 4, Crus cerebri. 
5, Pons Yarolii. 6, Medulla oblongata. The 
line with end dots, from corpus quadrigem- 
inus to the medulla oblongata, indicates the 
intimate connection of these two centres 
with each other, in regard to the function of 
this nerve. 
FOURTH PAIR OF CRANIAL NERVES—THE TROCHLEARIS. 
The Trochlearis, or Patheticus (one from each hemisphere), is 
the smallest cranial nerve (Fig. 45). Its fibres originate at the lat- 
eral walls of the valve of Vieussens, also at the posterior part of 
the crus cerebri just beneath the corpora quadrigemina, and some 
fibrillae from the upper anterior part of the fourth ventricle. Pass- 
ing then to the floor of the Sylvian aqueduct, and through the 
sphenoidal fissure into the orbit, it is distributed exclusively to the 
superior oblique muscle of the eyeball. It possesses the physiolog- CRANIAL NERVES 
175 
ical property of transmitting the material impulses for involuntary 
motion to said muscle, act- 
ing in harmony with the 
oculomotorius nerve to pre- 
serve the horizontal plane 
of the eyeball; but in co- 
ordinated movements, the 
trochlearis carries the ma- 
terial impulses which are 
under the control of the 
will. Its paralysis inca- 
pacitates the rotation of the 
eyeball and double vision 
(diplopia) ensues. Le- 
sion at the origin of its 
fibres at one hemisphere af- 
fects the eyeball on the op- 
posite side, since the great- 
er number of fibres of this 
nerve decussate near the 
origin. 
Fig. 45. 
Diagram of the trochlear nerve. 
A, Cerebrum. B, Cerebellum. C, Troch- 
lear nerve. 
1, Corpus quadrigeminus. 2, Pons Yarolii. 
3, Medulla oblongata. 
FIFTH PAIR OF CRANIAL NERVES—THE TRIGEMINUS 
The fifth nerve (one from each hemisphere) is termed Trigem- 
inus (threefold). It originates from two roots of fibres: the first, 
a large posterior root (sensory) of about seventy to one hundred 
nerve filaments springing from a nucleus of cells on the floor of the 
fourth ventricle and on the posterior horn of gray matter of the 
spinal cord, as far down only as the second vertebra, also from the 
lateral portion of the pons Yarolii; the second, a small anterior 
root (motor) of about twenty nerve filaments, arising from a nu- 
cleus of cells at the lateral angle of the fourth ventricle and pyr- 
amidal body. 
The trigeminus nerve includes more nerve-fibres than any other 
cranial nerve, and passes to the Gasserian ganglion (semilu- 
nar) (D, Fig. 46), lodged in a depression near the apex of the pet- 
rous portion of the temporal bone. Its fibres carry material im- 
pulses for three different functions: special sense (taste), common 
sensory—i. e., a function involving diverse external senses, and mo- 
tory. It is the great sensitive nerve of the skin of the head, face, 
and nasal mucous membrane, also the motor nerve for the muscles 176 
CRANIAL NERVES. 
of mastication. The Gasserian ganglion gives off three nerves: the 
ophthalmic (E), superior maxillary (H), and inferior maxillary 
(K). 
The Ophthalmic is its first division, and carries sensory im- 
pulses, supplying the eyeball, lachrymal gland, mucous lining of 
the eye and nose, the integument and muscles of the eyebrow, nose, 
and forehead. It consists of 
fibres from the origin of the 
fifth pair and some addition- 
al from the Gasserian (semi- 
lunar) ganglion. The oph- 
thalmic divides into three 
branches: lachrymal, frontal, 
and nasal, which pass through 
the sphenoidal fissure into 
the orbit. If its nasal branch 
be injured or irritated, the 
mucous membrane of the na- 
sal passage swells and be- 
comes obstructed by mucus, 
which assumes a fungus con- 
sistency, and is liable to 
bleed at the slighest touch. 
The sense of smell is then 
marred, as in influenza, while 
the olfactory nerves are in- 
active on account of the al- 
teration of the mucous mem- 
brane and its secretions. 
The Superior Maxillary is the second division of the fifth 
nerve. This also carries sensory impulses. It contains fibres from 
the origin of the fifth, and some additional from the Gasserian 
(semilunar) ganglion, then passes through the foramen rotundum, 
and supplies the teeth, gums, mucous membrane of the upper jaw, 
lower part of the nose, the integument of the lower eyelids, the 
muscles of the nose, temple, and side of forehead, the skin, and 
mucous membrane of the upper lip. 
The Inferior Maxillary is the third division of the fifth 
nerve. It is a mixed nerve—i. e., both sensory and motor. It also 
contains fibres from the origin of the fifth, and some additional 
from the Gasserion ganglion, and passes out of the skull through 
Fig. 46. 
Diagram of the trigeminus nerve. 
A, Cerebrum. B, Cerebellum. C, Fifth, 
3r trigeminus nerve. D, Gasserian ganglion. 
E, Ophthalmic nerve. H, Superior max- 
illary nerve. K, Inferior maxillary nerve. 
1, Pons Yarolii. 2, Medulla oblongata. 
3, Cervical portion of the spinal cord. CRANIAL NERVES. 
177 
the foramen ovale in the sphenoid bone, supplying the teeth and 
gums of the lower jaw, integument of the temple and ear, lower 
part of the face and lower lip, the muscles of mastication, and the 
tongue with a nerve for its special sense of taste. 
The three branches just described constitute principally one of 
the fifth pair of cranial nerves, their physiological property being 
principally to convey sensory impulses. The parts supplied by 
this nerve are the seat of all neuralgic affections about the head and 
face. The lingual branch of the inferior maxillary is not only 
necessary to the sense of taste, but it also enables us to realize when 
food is uniformly reduced by mastication, and whether some is left 
about the mucous membrane or teeth. With a tongue dry or coat- 
ed, as in febrile conditions, taste is marred, showing that it depends 
upon the special sensitiveness of the papillae of the lingual nerve on 
the tongue, as well as upon its moisture—i. e., on all the physiolog- 
ical conditions required for the integrity of the mucous membrane. 
Its muscular branch supplies the temporal and masseter muscles 
which bring the teeth of the lower jaw most powerfully in contact 
with the upper. Section of this nerve paralyzes the muscles of 
mastication; but if paralyzed on one side only, mastication may 
continue by lateral motion of the jaw. 
The fifth nerve may also affect sight. Impressions of light 
are transmitted exclusively by the optic nerve, but the anterior 
part of the eyeball, iris, and cornea are connected by sensory fibril- 
lae with the ophthalmic ganglion. If the trigeminus nerve be di- 
vided or injured within the cranium, or the Gasserian ganglion, it 
causes a change of nutrition in the cornea by vascular congestion, 
ulceration, and destruction of the eye; indicating that the impulses 
influencing nutrition of the eyeball are not by its own proper 
nerve-fibres of the trigeminus only, but also by additional fibrillge 
carrying impulses from the Gasserian ganglion. The cerebral areas, 
or centres of taste and smell, are placed near together at the 
bottom of the fissure of Sylvius. 
The Abducens Nerve (one from each hemisphere), originates 
by fibrillae from the lower posterior part of the pons Varolii and 
upper part of the anterior pyramid, or corpus pyramidale; also 
from the fasciculus teres on the floor of the fourth ventricle. It car- 
ries motor impulses to the external rectus muscle, effecting abduc- 
SIXTH PAIR OF CRANIAL NERVES THE ABDUCENS. 178 
CRANIAL NERVES. 
tion of the eyeball. The nerve-fibrillae of the upper origin, with 
those of the opposite partner, 
bend over the pons and join 
those of the deeper origin. 
The fibres then pass through 
the sphenoidal fissure, form- 
ing the abducens nerve, 
which supplies the external 
rectus muscle of the eye. 
The fibres bending over the 
pons may be easily pressed 
upon by any abnormality 
of the tentorium cerebelli; 
hence, both nerves are very 
liable to partial paralysis, 
causing strabismus (squint- 
ing), or diplopia (double- 
sight—i. e., seeing a single 
object as two). Squinting 
may also be caused by par- 
tial opacity of the cornea, or 
by injuries, shortness, or contraction of the external rectus muscle. 
Fig. 47. 
Diagram of the abducens nerve. 
A, Cerebrum. B, Cerebellum. C, Ab- 
ducens nerve. 
1, Pons Varolii. 2, Medulla oblongata. 
SEVENTH PAIR OF CRANIAL NERVES—THE FACIAL. 
The Facial Nerve (portio dura, Willis), one from each hemi- 
sphere, originates by fibres from the lateral tract of the medulla ob- 
longata, between the olivary and restiform bodies, and partly from 
the fasciculus teres on the floor of the fourth ventricle. It passes 
in company with the auditory nerve (8th) into and through the in- 
ternal auditory meatus, where the facial continues through the pe- 
trous portion of the temporal bone, coming out at the stylo-mastoid 
foramen, and is distributed to the side of the face in a fan-shaped 
manner. It communicates with the auditory, glosso-pharyngeal, 
and pneumogastric nerves; with the spheno-palatine (Meckel’s), 
and otic ganglia; carotid and cervical plexuses; parotid gland, and 
terminals of the fifth nerve in the integument of the face. The 
chorda tympani nerve branches off from the facial nerve just before 
it makes its exit from the stylo-mastoid foramen; it then passes to 
the lingual muscle. 
The facial nerve carries motor impulses to the muscles of the 
face, to those of the external and middle ear, palate, and tongue. CRANIAL NERVES. 
Its impulses on the muscles of the face change the features in their 
various movements to correspond with the varying phases of mental 
or emotional activity. A lesion or pressure on this nerve paralyzes 
all the superficial muscles of the face, thereby causing loss of ex- 
pression on the paralyzed side. 
The nostrils in man are more or less rigid, and nearly inactive in. 
their ordinary condition. They expand when the air is forcibly 
inspired, to assist in the sense of smell, or whenever the breathing 
is hurried or laborious through increased muscular exertion, or by 
any accidental obstruction 
of the air-passages. In case, 
however, of facial paralysis, 
the nostrils become com- 
pressed by inspiration, while 
during expiration they are 
forced outward. In this 
case their natural move- 
ments in respiration are re- 
versed. Such paralysis may 
be caused by disease of the 
facial nerve itself, disease at 
its origin in the brain, or by 
disease of the bony canal at 
the petrous portion of the 
temporal bone. If the lesion 
is located in the peripheral 
branches of the nerve, cer- 
tain facial muscles may be 
affected to the exclusion of 
others; for instance, the mus- 
cles about the lips may be paralyzed without any perceptible loss 
of motion in the parts above; but if located on the central trunk 
of the nerve, or if it involves the whole of its origin, then the con- 
sequences extend uniformly over one side of the face, forming a 
complete unilateral facial paralysis (Bell’s). As the muscles on 
the paralyzed side are no longer antagonistic to those of the other, 
the face is drawn over to the healthy side, and may be accompa- 
nied by disturbances of mastication, deglutition, speaking, and taste. 
The secretion of saliva may also be interfered with. The orbicu- 
laris palpebrarum likewise becomes powerless, the eye remains 
open, the angle of the mouth is lower, and during mastication some 
Fig. 48. 
Diagram of the facial nerve. 
A, Cerebrum. B, Cerebellum. C, Facial 
nerve. 
1, Pons Varolii. 2, Medulla oblongata. 
3, Olivary body. 180 
CRANIAL NERVES. 
food remains between the cheek and gums. An abnormality of 
taste on the same side as the facial paralysis is a symptom that 
fixes the location of the lesion of the facial nerve, at some point 
inside the stylo-mastoid foramen. 
EIGHTH PAIR OF CRANIAL NERVES—THE AUDITORY. 
The Auditory Nerve, or nervus acusticus, is soft, and hence 
is termed portio mollis of the 7th (Willis). It arises from three 
roots: one large anterior root and a small posterior one, each at a 
median and a lateral nucleus. 
These four nuclei (tubercula acus- 
tica) are situated in the floor of 
the fourth ventricle in connection 
with the posterior pyramid and 
restiform body. The fibres of 
these two roots carry the impulses 
from the cochlea and vestibule 
of the internal ear for hearing. 
The third root arises at the 
superior vermiform process of the 
cerebellum (Fig. 49), and carries 
the impulses from the semicircu- 
lar canals of the ear labyrinth 
for maintaining the equilibrium 
of the head and of the body. All 
the fibres of the three roots com- 
bine and enter the internal audi- 
tory meatus, where this nerve 
receives a few fibres from the 
facial nerve (7th). It passes 
onward to the internal ear, and 
is distributed to the vestibule, 
cochlea, and semicircular canals. 
The auditory nerve carries impulses for the sense of hearing, 
and governs the equilibrium of the body, as it is intimately con- 
nected with the auditory area in the cerebrum, also with the cen- 
tres of the sense of position of the head and body, and with the 
sense of direction of space. Stimulation of the auditory nerve 
in any part of its course, or at its termination in the vestibule 
or cochlea, produces the sensation of sound. Stimulation at 
its termination in the semicircular canals determines the proper 
Fig. 49. 
Diagram of Auditory Nerve. 
AA, The occipital bone partly re- 
moved, exhibiting the posterior por- 
tion of the brain. B, Cerebellum. 
C, Auditory nerve. D, External ear. 
H, Internal auditory meatus. E, 
Sensation centre of hearing. 1, Pons 
Varolii. 2, Medulla oblongata. CRANIAL NERVES. 
181 
position of the head and body; while any irritation to said canals 
disturbs the equilibrium, more or less, ot the head or body, or of 
both; also disturbing the proper direction. (Vide Semicircular 
Canals in chapter on Ear and Hearing.) 
NINTH PAIR CRANIAL NERVES THE GLOSSO-PHARYNGEAL. 
The Glosso-pharyngeal Nerve, one from each hemisphere, 
contains sensory and motor fibres, some of which arise behind the 
olivary body of the medulla oblongata, carrying impulses for the 
sense of taste and for deglutition. Some fibres arise from a nucleus 
of cells at the lower half 
of the floor of the fourth 
ventricle, carrying the sen- 
sory impulses from the mu- 
cous membrane of the 
pharynx, fauces, and tonsils. 
After leaving the centres of 
origin, the fibres join and 
the nerve proper is formed, 
receiving its neurilemma 
from the dura mater, just 
when passing from the cra- 
nium in company with the 
pneumogastric and spinal 
accessory nerves through the 
jugular foramen. At this 
foramen the nerve passes 
through the jugular gang- 
lion, and at the petrous por- 
tion of the temporal bone 
proceeds through the pet- 
rous, or Andersh’s, ganglion. 
It sends off one branch to the tongue, and another to the pharynx, 
tonsils, and soft palate. Its function is to transmit material impuls- 
es for two different, but associated, phenomena: l,the sense of taste; 
2, the impulses of reflex action for deglutition. The latter at first 
is voluntary; but as soon as food has passed the epiglottis, deglu- 
tition is performed involuntarily by reflex action, even during un- 
consciousness. The stimulus for deglutition is the food or liquid 
on the surface of the mucous membrane of the fauces and pharynx. 
The impulse is conveyed by the glosso-pharyngeal nerve inward to 
Fig. 50. 
Diagram of the glosso-pharyngeal 
nerve. 
A, Cerebrum. B, Cerebellum. C, Glosso- 
pharyngeal nerve. D, Area, or centre, of 
taste. 
1, Pons Varolii. 2, Medulla oblongata. 182 
CRANIAL NERVES. 
the medulla oblongata, which by reflex action forwards a motor im- 
pulse, passing with fibres of the pneumogastric to the pharynx. 
Natural stimulants, such as proper food or liquid in contact with 
the mucous membrane of the pharynx, excite deglutition; while un- 
natural substances, like a finger or a feather, produce vomiting. 
Nauseous or irritating substances, too, cause more or less abnormal 
reflex actions to the muscular fibres in the walls of the throat, 
oesophagus, stomach, and diaphragm, resulting in vomiting. 
The Tongue is supplied with three nerves—the lingual (gusta- 
tory), sensory, hypoglossal, motor", and glosso-pharyngeal, sensory 
and motor. The sense of touch on the tongue indicates that this 
organ contains, at least, four varieties of terminal nerve-bulbs of 
taste; i. e., for sweet, acid, bitter, and saline. The function of one or 
of several of these varieties of bulbs may become diminished or par- 
alyzed, while those for saline or acid tastes, are not affected. 
The Sense of Taste is localized in the terminal bulbs of the 
papillae in the mucous membrane of the tongue, and slightly also 
at the soft palate and pillars of the fauces. Its sensory impulses 
are carried by two nerves — the glosso-pharyngeal and the lin- 
gual branch of the fifth nerve. Taste for sweet and acid matters is 
most acute at the tip of the tongue, and less so on the back part; 
while for bitter and saline, it is most acute at the back part, and 
least at the tip. All sensations of taste are more acute on the left 
edge of the tongue than on the right. The terminal bulbs (Fig. 36) 
are minute oval bodies about l-300th of an inch in length, and 
l-800th of an inch in width, and where they are the most numerous 
there the sense of taste is the most acute. An increased sense of 
taste is called hypergeusia; a diminished is called hypogeusia; and 
the loss of taste is termed ageusia. To excite a sensation of taste, 
the stimulating substance must be soluble in the fluid of the mouth. 
An insoluble substance in contact with the tongue causes the sen- 
sation of touch or temperature only, but excites no taste. Smell is 
closely associated with taste, for, if a substance is tasted, its aroma 
(smell) is perceptible at the same time. If the nose be closed 
during the act of swallowing or tasting, the sense of taste is greatly 
diminished. It also requires that the substance tasted be in a state 
of solution, as a solid substance causes the impression only of a 
foreign body. Substances with an unpleasant taste, when placed on 
the back part (root) of the tongue, often induce vomiting, but have 
little or no nauseous effect when placed on the forward part. The 
glossal branch of the glosso-pharyngeal nerve is distributed to the CRANIAL NERVES. 
183 
mucous membrane and papillae of the root of the tongue, and car- 
ries the impulse of sensation of taste of that part. The hypoglos- 
sal nerve supplies the muscular portion of the tongue; while the 
lingual (gustatory) branch of the fifth nerve carries the impulse 
of sensation from the taste bulbs in the mucous membrane of the 
anterior two-thirds of the tongue. Substances in solution pen- 
etrate to the papillae of the tongue by endosmosis and by attraction 
of the cells in the papillae. With a coated tongue, therefore, taste 
is more or less vitiated. An impression on the terminal bulbs of 
the papillae is retained for some time, so that in tasting different 
flavors repeatedly in quick succession no difference can be distin- 
guished. By tasting a highly flavored medicine nauseous drugs 
may be swallowed pleasantly. (See Terminal Bulb.) 
TENTH PAIR OF CRANIAL NERVES—THE PNEUMOGASTRIC. 
The Pneumogastric (Vagus) Nerve (Fig. 51), one from each 
hemisphere, is composed of sensory and motor fibres. The fibres of 
its origin proper, are sensory only, and arise from the posterior part 
of the floor of the fourth ventricle. Its motor fibres are derived 
from other sources, since it receives nerve-fibres from the spinal ac- 
cessory, glosso-pharyngeal, and hypoglossal. It gives off ten branch- 
es; viz., auricular, pharyngeal, laryngeal (superior, and recurrent), 
cardiac (cervical, and thoracic),pulmonary (anterior, and posterior), 
oesophageal, and gastric. The fibres, after leaving the centres of 
origin, join, and the nerve proper is formed, receiving its neurilem- 
ma from the dura mater just when passing from the cranium in 
company with the glosso-pharyngeal and spinal accessory nerves 
through the jugular foramen. It supplies the pharynx, larynx, 
organs of the voice, trachea, oesophagus, lungs, heart, thorax, stom- 
ach, and greater part of the intestines. This nerve is the channel 
through which the sensory impulses for respiratory and circulatory 
movements are conveyed to the medulla oblongata, which sends 
forth reflex impulses to the lungs, respiratory muscles, and to the 
heart. It also wields an important influence in digestion, as it sup- 
plies the walls of the stomach with sensory nerve-fibres. The reflex 
impulses carried by its motor fibres are derived not only from the 
respiratory and circulatory centres, but also from other centres, the 
fibres of which run within the pneumogastric nerve, such as those 
contributing from the spinal accessory, glosso-pharyngeal, hypoglos- 
sal, and others already mentioned. The reflex impulses carried by 
its motor fibres call forth not only normal activities of already 184 
CRANIAL NERVES. 
stated organs, but also (if irritated) a variety of abnormal reflex 
phenomena, such as coughing, and vomiting. (See Respiration, 
Circulation, Heart, Arteries, Stomach, Saliva, and Voice.) 
Fig. 51. 
Diagram of the pneumogastric nerve. 
A, Cerebrum. B, Cerebellum. C, Pneumogastric nerve. D, Laryngeal 
branches. E, Pharyngeal branch. R. L, Pulmonary branch to right lung. 
L. L, Pulmonary branch to left lung. T, (Esophageal branch. H, Cardiac 
branch. N, Gastric branch joining the coeliac and splenic plexuses. S, Gas- 
tric branch to anterior surface and curvatures of the stomach. M, Branch 
joining the hepatic plexus. 
1, Pons Varolii. 2, Medulla oblongata. 3, Cervical portion of the spinal 
cord. 
ELEVENTH PAIR OF CRANIAL NERVES—THE SPINAL ACCESSORY. 
The Spinal Accessory Nerve (Fig. 52), one from each half 
of the medulla oblongata and spinal cord, arises from two roots, 
one from cells near the vagus nucleus on the floor of the fourth 
ventricle in the medulla oblongata, the other from cells in the an- CRANIAL NERVES. 
185 
terior and posterior horns of gray matter in the spinal cord between 
the 4th and 6th cervical vertebrae (3, Fig. 52). From this latter 
origin emerge a series of separate rootlets that collectively pass up- 
ward through the foramen magnum, there joining the fibres from 
the medulla, then incorporating with the pneumogastric (vagus) 
Fig. 52. 
Diagram of the spinal accessory nerve. 
A, Cerebrum. B, Cerebellum. C, Spinal accessory nerve, where it runs in 
the same sheath with the pneumogastric nerve. D, Branch communicating 
with the pharyngeal branch of the vagus. E, Branch communicating writh 
the superior laryngeal branch of the vagus. Y, Branch supplying the sterno- 
mastoid muscle. S and T, Branches supplying the trapezius muscle. 
1, Pons Yarolii. 2, Medulla oblongata. 3, Cervical portion of the spinal 
cord. 
nerve, with which they pass from the cranium through the jugular 
foramen. It supplies, either directly or by anastomosis, motor in- 
fluence to the pharynx and larynx, and the sterno-mastoid and 
trapezius muscles. Some of its fibres are connected with the car- 
diac plexus. It controls, also, the vocal organs. Section or sufficient 
injury to it causes loss of power to produce vocal sounds. Other 
movements, such as the peristaltic in the larynx for deglutition, are 
not interfered with. Section of the pneumogastric, however, paral- 
yzes the glottis, the organs of respiration, phonation, and deglutition. 186 
CRANIAL NERVES. 
TWELFTH PAIR OF CRANIAL NERVES—THE HYPOGLOSSAL. 
The Hypoglossal Nerve (one from each hemisphere) arises 
from some fibres in a groove between the pyramidal and olivary 
body, and some from a nucleus of cells at the anterior and lowest 
portion of the fourth ventricle. The fibres join, and the nerve prop- 
er is formed by receiving its neurilemma from the dura mater just 
when passing from the cranium through the anterior condyloid for- 
amen. The fibres all arise anteriorly, and, therefore, physiologic- 
ally carry motor impulses to the tongue and most of the muscles 
Fig. 53. 
Diagram of the hypoglossal nerve. 
A, Cerebrum. B, Cerebellum. C, Hypoglossal nerve. T, Its muscular 
branches to the tongue. H, Its descendens noni branch. 
1, Pons Yarolii. 2, Medulla oblongata. 
arising from the hyoid bone. Its fibres of the lower origin decus- 
sate at the median line; therefore, cases of facial paralysis may be 
accompanied by paralysis of the tongue on the same side with that 
of the face, being the side opposite the lesion. One of the genio- 
hyo-glossal muscles in this case loses its power, while the muscle 
opposite remains active; so that in protrusion of the tongue it is 
drawn to one side. The motor influence of this nerve is essential in 
mastication, deglutition, and in articulation of speech. Section or 
injury to the nerve either stops or interferes with the reflex actions 
for these functions. CHAPTER XX. 
THE EYE AND THE SENSE OF SIGHT. 
The Eyeball (bulbus oculi) (Fig. 54) is the organ of sight-, and, 
considered as an optical instrument, may be said to resemble a 
camera obscura. It is held in position in the orbit by the surroun- 
ding muscles, eyelids, and optic nerve. 
The Sclerotica or Sclerotic Coat (Fig. 54) is a tough, re- 
sisting membrane, which surrounds the eyeball externally. Its 
anterior -segment is termed the Cornea, and is composed of five 
layers of horny, fibrous, unyielding tissue, and is perfectly trans- 
parent. The cornea has no blood-vessels, but is supplied by nerve- 
fibres from the ciliary nerves. It differs in this respect from the 
other portions of the sclerotica, which consists of white and 
elastic fibrous tissue, opaque, very hard and dense, and forms 
an unyielding membrane, impervious to light. The sclerotica re- 
ceives the insertions of the recti and oblique muscles of the eye- 
ball, and is well supplied with ciliary vessels and nerves. The 
cornea may become altered in structure through pressure or tension, 
in which case it presents an opaque, milky appearance, like the rest 
of the sclerotic coat. 
The Choroid coat of the eye (Fig. 54) is a highly vascular, 
opaque, blackish brown pigment membrane lying between the scle- 
rotica and retina. Its dark color and density prevent dispersion of 
the rays of light within the eye, thereby favoring the absorption by 
the retina of all the light that enters the eye. 
The Hyaloid Membrane is a thin, soft, gelatinous, structure- 
less membrane surrounding the vitreous humor, into which it sends 
numerous transparent, clear processes for the support of the hu- 
mor. These processes serve to equalize the pressure of the sur- 
rounding membranes. (Vide Vitreous Body.) 
The Vitreous Body, or Humor, is a soft, gelatinous, transpar- 
ent, glossy structure, filling about four-fifths of the eye-globe post- 
eriorly, where it is surrounded by the retina. It is composed of wa- 
ter, mucin, salts, and albumen. It contains no blood-vessels, its 
nutrition being imbibed from vessels of the retina and ciliary pro- 188 
THE EYE AND THE SENSE OF SIGHT. 
cesses. Possibly, the amoeboid and multipolar cells contained in 
the vitreous body are more or less stimulated to activity by the dif- 
ferent color-vibrations, whereby a difference of stimuli on the ret- 
ina may be produced. 
The Aqueous Humor is a limpid liquid, consisting of nearly 
pure water, with traces of albumen and chloride of sodium. It is 
enclosed in a cavity between the cornea and lens (Fig. 54). This 
cavity is divided by the iris into two chambers—an anterior and a 
posterior. The Anterior Chamber is bounded by the cornea, 
iris, ciliary muscle, and ligament; and is tilled with aqueous hu- 
mor. The Posterior Chamber is bounded by the iris, lens, and 
suspensory ligament; it also is filled with aqueous humor. 
Fig. 54. 
Diagram of the eye. 
The Ciliary Muscle forms a circular band, about one-eigbtb 
of an inch broad, lying on the fore part of the choroid coat, thick- 
est in front and tapering behind in the part attached to the cho- 
roid, just in front of the retina. When this muscle contracts it 
compresses the vitreous humor; or, possibly, by pulling on the cili- 
ary processes, at the same time relaxing the suspensory ligament, it 
assists the lens to protrude forward (increases its convexity), thus 
facilitating accommodation of sight for different distances. Its ar- 
teries and nerves are derived from the ciliary arteries and nerves. THE EYE AND THE SENSE OF SIGHT. 
189 
The Ciliary Ligament consists of circular, elastic fibres, about 
one-fourth of an inch thick, anterior to the ciliary muscle, and con- 
taining the canal of Schlemm. It surrounds the iris, and connects 
together the cornea, sclerotica, iris, and outer fore part of the 
choroid. 
The Suspensory Ligament of the lens is a transparent, tough, 
elastic, fibrous membrane between the vitreous humor and front 
portion of the ciliary processes, connecting with the border of the 
lens near its circumference, thereby constituting by its anterior 
layer a part of the boundary of the posterior chamber. Its inter- 
nal layer is attached to the ciliary processes. It is also connected 
with the anterior portion of the retina, assisting in retaining the 
lens in position. 
The Canal of Petit is a triangular passage, about one-tenth of 
an inch in size, around the border of the lens, lying within the two 
layers of the suspensory ligament. 
Pupil, action of: Vide Iris. 
The Iris (rainbow-like, on account of its many colors) is a thin, 
circular, contractile, muscular curtain, suspended behind the cor- 
nea, but in front of the lens (Fig. 54). Its color constitutes the 
color of the eye (so-called). The orifice in the center is the pupil— 
“the window of the eye”—whose function is the regulation (by in- 
voluntary enlargement and contraction) of the quantity of light 
admitted to the interior chamber of the eye. This regulative func- 
tion prevents strong light from dazing the vision, or injuring the 
retina. A few strong rays affect the retina more severely than 
many weak ones. The iris divides the cavity between the cornea 
and lens into two chambers (an anterior and a posterior), which 
freely communicate in the center through the pupil (Fig. 54). 
When rays of light focus on the retina the iris contracts and the 
pupil becomes small, through reflex action; the afferent nerve be- 
ing the optic, the efferent, the oculomotorius through the ciliary 
fibres from the ophthalmic ganglion. The movements of the iris are 
involuntary. The impression of light is conveyed by the optic 
nerve to the anterior tubercle of the corpora quadrigemina, which 
transfers the impulse to the valve of Yieussens, crus cerebri, and 
medulla oblongata (Fig. 43, and Fig. 44). There the oculomoto- 
rius nerve (third) originates, through which is transmitted a reflex 
impulse passing to the ophthalmic ganglion, thence through the 
ciliary nerves to the iris, for contraction. The contraction is there- 
fore produced through reflex action. The destruction of the corpora 190 
THE EYE AND THE SENSE OF SIGHT. 
quadrigemina abolishes the reflex centre, and the iris (pupil) 
remains dilated, whatever be the intensity of the light. The iris 
contracts and the pupil becomes small, not only through the influ- 
ence of intensified light, but also from any condition producing 
congestion of the blood vessels of the eyeball; from accommoda- 
tion for near objects; and from the use of nicotine, opium, or phy- 
sostigmine. Passing suddenly from light to darkness obscures 
sight, until a sufficient dilatation of the iris and consequent en- 
largement of the pupil has taken place; but passing from darkness 
to bright light dazes the eye from inability of the iris to contract 
with sufficient rapidity. Strong light on one eye causes contrac- 
tion of the pupils of both eyes, the contraction being due to an im- 
pulse through both oculomotorius nerves from within outward. 
A brilliant light may so contract the iris that its traction on the 
ciliary and suspensory ligaments will injure the retina. The reflex 
impulses by which the iris (pupil) contracts (see corpora quadri- 
gemina) or expands (see cilio-spinal centre) under varying degrees 
of light pass through the ophthalmic ganglion. The iris, therefore, 
acts sluggishly because the intervening ganglion belongs to the 
sympathetic system. Sectiop of the oculomotorius nerve produces 
permanent dilatation of the iris. The centre for its normal dilata- 
tion lies at the lower cervical portion of the spinal cord, from 
which nerve-fibrilla3 issue to the cervical sympathetic ganglion, 
and then pass to the ophthalmic ganglion. Section of these fibrillse 
near the spine causes permanent contraction of the iris. It is 
stated above that any condition producing congestion of the blood- 
vessels causes the iris to contract. Now, any cause relieving the 
blood-vessels produces dilatation; such as diminished light, vision 
for a distant object, mental depression, or such drugs as atropia 
and hyoscyamine. 
Nerves.—The circular muscle-fibres of the iris are supplied by 
branches of the short ciliary nerve from the ophthalmic ganglion. 
The fibres are derived primarily from the oculomotorius nerve and 
from the cervical sympathetic ganglion. The elongated or radiat- 
ing muscular-fibres of the iris are supplied by two or three long 
ciliary nerve-branches from the nasal nerve, running with the short 
ciliary from the ophthalmic ganglion to the iris. Under normal 
conditions the sympathetic impulses are much more powerful, and 
may overcome contraction. Some stimulants, such as bright light, 
opium, calabar bean, tobacco, chloroform, and alcohol (first stage), 
stimulate the contracting centre and paralyze the dilator; while 
others, such as darkness, fear, horror, or such drugs as atropia, hyos- THE EYE AND THE SENSE OF SIGHT. 
191 
cyamine, chloroform, and alcohol (latter stage), stimulate the di- 
lating centre, and paralyze the contractor. 
The Lens is a crystalline, double-convex, transparent body. 
Regarding its position in the eye, it is about a third of an inch in 
transverse and about one-fourth in antero-posterior diameter (Fig. 
54). It weighs three to four grains. It is composed of layers of 
fibres, the density of which increases from without inward, the 
central or nucleus portion being the most dense. Its substance con- 
sists of about 70 per cent water, 25 per cent crystalline solid mat- 
ter, and about 5 per cent of albumen, fat, salts, and cholesterin. It 
refracts the rays of light to a focus on the retina. ( Vide Accommo- 
dation of the Eye.) 
The Ciliary Processes, numbering about sixty to eighty, large 
and small, lie side by side, and are attached to folds running back- 
ward from the posterior margin of the suspensory ligament to the 
anterior part of the retina (Fig. 54). 
The Retina is a soft, delicate, semi-transparent membraneous 
expansion of the optic nerve. It is situated between the hyaloid 
Fig. 55. 
Diagram of the layers of the retina. 
1, Retina. 2, Pigmentary layer. 3 and 4, Jacob’s 
membrane of rods and cones (3, the rods; 4, the 
cones). 5, Membrana limitans externa. 6, Outer 
nuclear layer. 7, Outer molecular layer. 8, Inner 
nuclear layer. 9, Inner molecular layer. 10, Ves- 
icular layer. 11, Layer of optic nerve-fibres. 12, 
Membrana limitans interna, with blood-vessels 
and optic nerve-fibres. 
membrane and choroid coat, extending from the entrance of the 
optic nerve outward and forward to the ciliary processes (Fig. 54). 
Its greatest thickness, at the entrance of the optic nerve, is only 
about l-120th of an inch. As it proceeds forward it diminishes to 
l-200th of an inch. The sensitive elements of the retina are in the 
macula lutea (limbus luteus), termed Jacob’s membrane. This is the 
layer of rods and cones on which luminous rays have their pecul- 
iar effect. The macula lutea is a roundish yellow pigment spot, 
about l-20th of an inch in diameter, on the retina directly on the 192 
THE EYE AND THE SENSE OF SIGHT. 
axis of vision, where the layers of the retina are much thinned. 
{ Vide Light and Sight.) 
The Optic Nerve (Fig. 43, and Fig. 54) contains only sensory 
fibres, transmitting the normal impulses received from the retina to 
the visual centre of the brain, which is required, as we have seen in 
the chapter on sensation, for the production of the external sensa- 
tion of light. If the optic nerve in any part of its course is arti- 
ficially stimulated, either mechanically or electrically, a sensation 
of light is also produced, as such stimulation, too, is transmitted 
to the rods and cones of the retina. Luminous impressions in the 
■eye, as sparks, for instance, may be caused by pressure externally 
on the eyeball when in the dark, or by fatigue, of the retina from 
too strong light or too continued gaze, such as in reading, and 
afterwards closing the eyes. (See Optic Nerve.) 
The Movements of the Eyeball are produced by six muscles 
arising from the contour of the optic foramen and vicinity, and at- 
tached to the sclerotic coat. Four muscles are straight, and termed 
external, internal, superior, and inferior recti, moving the eye out- 
ward, inward, upward, and downward. Whenever the external or 
the internal rectus muscle permanently contracts, or the opposing 
muscle is paralyzed, strabismus is the result. The impulses through 
the oculomotorius (third) nerve principally move the muscles of 
the eyeball. The superior oblique muscle, however, is actuated 
through the trochlearis (fourth), the external rectus through the 
abducens (sixth). 
Nerves and Arteries.—The sensory impulses of sensations of 
the eyeball and lid are carried through the ophthalmic branch of 
the fifth nerve. By and through the ophthalmic and ciliary gang- 
lia, the sensory branches of the fifth, the motor branches of the 
third, and the sympathetic filaments of said ganglia, are united. 
Among the various parts that make up the eye the terminal cones 
and rods on the optic nerve-fibres are the most important, as being 
more intimately and radically concerned in the operation of seeing. 
The motor muscles of the eye are supplied by the third, fourth, and 
sixth cranial nerves. The third sends fibres to all the muscles of 
the orbit, except the superior oblique and external rectus. The su- 
perior oblique is supplied by the fourth, and the external rectus by 
the sixth. (For Nerves of the Iris, see Iris.) 
The Arteries are derived from the long anterior ciliary. 
The Eyelids, or Palpebrae, protect the eye from injury. The 
upper lid has the levator palpebrae superioris muscle for upward THE EYE AND THE SENSE OF SIGHT. 
193 
movements. The tarsus, inside of the lid, is a rigid plate of connect- 
ive tissue, though fibro-cartilaginous in appearance, and keeps the 
lid in form and shape. The Meibomian glands, about thirty in 
number, on the inner surface of the eyelids, contain cells which se- 
crete a sebaceous matter to prevent adhesion of the lids. The con- 
junctiva, or mucous membrane on the inner surface, is continuous, 
and reflected over a portion of the sclerotica. On the inner edge of 
the lids it converges into the lachrymal canal. The lachrymal gland 
is a flattened body, about the size of an almond, at the superior ex- 
ternal angle of the orbit, and secretes the tears by stimulus through 
the lachrymal nerve. The orbicularis oculi (circular muscle) con- 
tracts the lids. In its paralysis, however, the lid on the affected eye 
cannot be closed; and even during sleep it remains open, because the 
two muscles that open and close the eyelids are controlled by two 
different nerves; i. e., the levator palpebrae superioris, supplied by 
the oculomotorius (third) nerve; and the orbicularis oculi, which 
receives fibrillae from the facial (seventh) nerve. In paralysis 
of said orbicularis, the lids cannot contract (close); and, in paralysis 
of the nerve fibres of said levator palpebrae superioris, the lids can- 
not be raised (opened), although the movements of the eyeball may 
be unaffected and the pupil capable of dilation and contraction as 
before. The movement called winking is likewise suspended. Wink- 
ing of the eyelids may be produced voluntarily; but generally it 
takes place involuntarily through reflex action, excited by contact 
of air with the cornea, and the accumulation of tears along the edge 
of the lower lid. At short intervals this produces an instantaneous 
contraction by reflex, through the orbicularis muscle, the edges of 
the eyelids being brought together and again immediately separ- 
ated, in that manner spreading the moisture of the lachrymal 
secretion uniformly over the cornea and protecting its surface from 
dryness and irritation. In said paralysis the motor power is lost, 
but the sensitiveness remains. 
The Accommodation of the eye is the power of its crystalline 
lens to increase or diminish its convexity so as to focus on the 
retina the rays of light reflected from objects situated at varying 
distances from the eye. An object is seen according to the light 
it reflects on the eye. Light itself is not visible. An image is a 
picture of an object. To be perfect, the rays from all points of 
the object must not intersect, but each ray must arrive at its own 
point on the image. That the appreciation of light is by the 194 
THE EYE AND THE SENSE OF SIGHT. 
reflection of rays from an object, is proved by darkening a room and 
admitting a sunbeam through a minute aperture. The light-rays 
can be traced by the reflection of the particles of dust floating in 
the room. If the air in the room be purified from dust, the rays 
of light cannot be traced; in fact, the part which the sunbeam 
traverses appears as dark as the rest of the room. The object 
alone on which the rays strike and reflect is visible. The appar- 
ent size of an object is diminished according to its distance from 
the eye. The power of estimating distance is acquired by habit 
and improved by practice. With one eye a person may see as far, 
but not as clearly, as with two eyes, for, with two eyes we see the 
object from two different points of view, which gives at once a better 
idea of the proportions of its different parts. That two eyes are 
required to properly estimate distance is shown when a one-eyed 
person tries to quickly dip a pen into an inkstand. If we shut one 
eye and try to place a stopper quickly into the opening of a bottle, 
the first attempt is seldom a success, for we either overreach or fall 
short of the mark. The power of estimating distance is greater in 
persons whose eyes are set far apart and movable from side to 
side. The accommodation for distance may be changed about 
three times in a second; but from a near to a distant object it is 
effected much more rapidly than vice versa. The born blind, see- 
ing suddenly, cannot at first judge distance. An infant, not hav- 
ing arrived at the age of reason, or an adult deprived thereof, will 
reach out his hands to seize the object desired, though it is far 
away. 
At any point farther distant than 65 metres, or about 225 feet 
(the punctum remotum), no accommodation is necessary. Any point 
from that up to the punctum proximum, which is about four inch- 
es from the eye, requires accommodation according to the distance. 
The latter is the limit of visibility for near objects. The range of 
accommodation is, therefore, from the punctum proximum to the 
punctum remotum. Accommodation is accomplished through the 
elasticity of the crystalline lens, which becomes thick or flattened, 
according to the distance of the object: thick when near, requiring 
positive accommodation—the anterior surface of the lens becoming 
more curved (convex); flattened (less curved) when very far off, no 
muscular action on the lens being then required—i. e., when the 
ciliary muscle is tranquil, as at rest, the iris relaxes, and the ciliary 
and suspensory ligaments partially suspend their action, the lens 
then lying flattened against the vitreous humor behind it. Conse- THE EYE AND THE SENSE OF SIGHT. 
195 
quently, in the latter case, near objects cannot be seen properly, 
while those at a distance can. 
A ray of light must traverse the cornea, aqueous humor, lens, 
and the vitreous humor, before it focuses at the retina. Changes in 
the figure of the lens are brought about by the iris and ciliary mus- 
cles. The circular and radiating fibres of these two muscles con- 
tract, thereby exerting sufficient pressure upon the border of the- 
lens to cause the protrusion of its anterior part, which becomes more 
convex, because at the pupil alone its advance is not resisted. The- 
aqueous humor displaced by the lens enters the anterior chamber,, 
and recedes on the flattening of the lens. The power of increasing, 
the convexity of the lens is diminished by advancement in age. 
To remedy this defect the person uses convex eye-glasses, to supply 
the want of convexity of the crystalline lens in accommodation 
for near objects. Artificial lenses for eye-glasses are generally 
made of crown or flint glass, in six forms:— 
Fig. 56. 
Diagram of artificial lenses. 
Thin at edge and thick in middle 
1. Double-convex. 
2. Plano-convex. 
3. Concavo-convex. 
4. Double-concave. 
5. Plano-concave. 
6. Convexo-concave. 
Thick at edge and thin in middle 
Lenses 1, 2, and 3, which are thickest at the middle, render par- 
allel rays convergent, whichever way they are turned; 4, 5, and 6, 
which are thinnest at the middle, whichever way these are turned, 
render parallel rays divergent. The focus, or focal point, is the 
point at which parallel rays that enter different parts of the lens 
intersect one another. The more powerful the lens the shorter the 
focal length. In case of absence of the eye-lens, accommodation is 
impossible. 196 
THE EYE AND THE SENSE OF SIGHT. 
Sight .—At the entrance of the optic nerve in the eyeball there 
are no rods nor cones, consequently no visual sensitiveness. That 
part of the retina is termed the blind, spot. The most acute area of 
vision is termed fovea centralis, which is a slight depression in the 
center of the macula lutea, directly in the axis of vision, being 
composed almost entirely of cones, about 2000 in number. This 
shows that the nerve-fibres are not the part sensitive to light, but 
that these parts are the cones, forming the terminal organs of said 
fibres. The rods and cones in the retina lie close together, except 
in the fovea centralis, which has only cones, showing that they 
are of more importance to sight. They lie a little deeper than the 
rods (3 and 4, Fig. 55). When some of the cones are destroyed 
it causes dark spots of vision. The rods extend nearer to the sur- 
face, and are also terminal organs of the optic nerve-fibres. By 
the rods the quantity of light is determined. The transverse dia- 
meter of each rod is about one micromillimetre, that of a cone 
about two. Impressions on the retina remain from the l-60th to 
the 1-30th of a second, experienced by the rapid rotary swinging 
of a burning torch, especially in the dark, which then appears 
like a ring, owing to the after-image. On account of the after- 
image the rapid and involuntary act of winking does not interfere 
with the continuous vision of objects, as in reading, for instance. 
The retina, in its adaptation for the reception and selection of 
the rays of light, makes the eye one of the five organs of the 
external senses. 
Light, 1 ike sound, is a quality of the ether accompanied by 
vibrations, and caused by a body termed in relation to it the 
“efficient cause.” The organ which appreciates this quality (light) 
is the eye, the organ of sight. The essential nature of light is not 
known. It is known as a physical fact, however, that light is 
propagated at the rate of about 186,000 miles in a second, and is 
capable of transmitting and imparting energy. Ether (properly 
aether) is a medium filling all space, within and outside of matter. 
Its rarity and elasticity are enormously greater than those of air. 
( Vide .Ether in chapter on Miscellaneous.) The velocity of light 
through ether is 186,000 miles in a second, while sound travels 
through air only l-5th of a mile in that time. The transmission 
•of energy through the medium of ether is termed radiation. One 
kind of energy we call light. Its luminous rays on the eye stimu- 
late the sense of sight. Rays of light-ether travel in vibrations, 
the impulse following by repetition, or periods. The color of bodies THE EYE AND THE SENSE OF SIGHT. 
197 
results from one portion of the colored rays contained in white 
light being absorbed at the surface of the body. If that portion 
which is unabsorbed traverses the body it is colored and transpar- 
ent; if refracted, it is colored and opaque. Distilled water in a 
glass appears white; by adding matter which changes the vibrations 
the white disappears, the color of the matter added being perceptible 
only. In this case, the increased additional color of one stratum 
has chemically changed and blended with the other, as well as 
altered the vibrations. The sensational effect of a stimulus on 
the external sense-organ does not proportionally affect the internal 
sense-organ, because the external sense-organ changes the logarithm 
of the stimulus. The vibrations of light-ether, their repetition and 
intensity, depend on force. The difference between the colors of the 
spectrum depend son the wave-lengths of light; or is a difference 
in frequency of vibration, just as in sound the number of vibrations 
in a given time determines the pitch of a note. (See Retina.) 
Color Blindness may be caused by a failure of certain cones 
in the retina to absorb light-ether of certain color vibrations, or it 
may be due to a defect in the area of sight in the cerebrum. This 
condition is illustrated by a person whose judgment on a certain 
subject may be entirely abnormal, while on others it is perfectly 
sound. Daltonism depends especially on the inability to distinguish 
red color. 
The Emmetropic Eye (normal) conducts parallel rays from 
distant objects to a focus on the retina without any effort of accom- 
modation of the crystalline lens, or aid on the part of the iris, cili- 
ary muscles, ciliary and suspensory ligaments. 
The Hypermetropic, or Hyperopic, Eye (short or flat 
eyeball) (A, Fig. 57) is long-sighted, the rays being abnormally 
refracted, and focused behind the retina (2). In this case the eye- 
ball is too short antero-posteriorly, though otherwise it may be 
normal in shape and healthy in function. With parallel rays from 
far objects the accommodation muscles do not require to be active. 
A proper convex eyeglass (converging the rays of light) will focus 
the rays at a shorter distance—that is to say, on the retina (4). 
The Myopic Eye, short or near sight (B, Fig. 57), must not be 
confounded with a dim or weak sight, because short-sightedness 
applies exclusively to the range, not to the power. The short-sighted 
eye is optically too powerful, and an object, at a moderate distance, 
is not properly focused. A person thus affected may possess the acut- 
est power of vision for near objects. If the eyeball is too long, then 198 
THE EYE AND THE SENSE OF SIGHT. 
the rays decussate, or focus within the vitreous body (6), before ar- 
riving at the retina, and consequently are not focused on the proper 
organ (8). The cause of myopia differs in different persons; in 
some it is caused by an over-convexity of the cornea, or the lens; 
in others from undue density or overabundance of aqueous humor 
Fig. 57. 
Diagram of a long, and a short-sighted eyeball 
A, Eyeball too short. B, Eyeball too long. 
1 and 5, Anterior portion of eyeball (cornea). 2, Focus behind the eyeball 
of a long-sighted eye (hypermetropic), the focus having passed the retina (4). 
3 and 7, Optic nerve. 4 and 8, Dotted line indicates the retina. 6, Focus 
within the eyeball, and not reaching to the retina (8) of a short-sighted eye 
(myopic); the eyeball is elongated. 
in the anterior and posterior chambers; from an elongated vitreous 
body; from a defective accommodation; or, as stated, from an elon- 
gated eyeball. The cause is often hereditary in families. Bonders 
believes the prolongation may depend on either one of three causes: 
“1. Pressure of the eye-muscles, during continued strong attempts 
at accommodation. 2. Increased pressure of blood in the eyes from 
a continued stooping position. 3. A congestive process, leading to 
softening and extension of the eye-membranes.” Short-sighted per- 
sons require concave glasses to remove the focal point farther back; 
i. e., on the retina (8, Fig. 57). 
Diplopia, or double vision, is of two kinds; caused, first, by a 
want of harmony in the movements of the eyes, the vision of each, 
separately, being perfect; second, there may be double vision with 
one eye only. The first may occur in squinting; the second, from 
paralysis of one or more muscles of the orbit. The latter form 
may arise from disease of the brain, cold, or overstudy. 
The Presbyopic, or long-sighted, eye (A, Fig. 57). The range 
of accommodation is here diminished, and the vision of near ob- 
jects interfered with; it is the failure of the power of accommoda- 
tion in advancing years. This condition is natural from youth to 
age, like gray hairs, and may occasionally be met with in young THE EYE AND THE SENSE OF SIGHT. 
199 
persons. This is not so much due to shortness of the eyeball, as 
is the case with hypermetropic eye. Presbyopia is a defect of 
accommodation, the lens by age becoming harder, its fibres less 
elastic, and the ciliary muscle weaker; consequently, the lens 
becomes flatter, and cannot accommodate itself for distinct vision 
of near or distant objects. In such a case a remedy may be found 
in the use of convex glasses of low power when reading, but not 
constantly, their occasional use being not so dangerous as the 
inconsiderate use of the concave. 
Hemeralopia, or night-blindness, is a peculiar form of inter- 
mittent blindness. The person can see perfectly with an ordinary 
light, but becomes partially or entirely blind at twilight. This 
affection is met with in tropical regions, the strong light of which 
may exhaust the retina, so that it is no longer capable of respond- 
ing to the weak rays of twilight or moonlight. A remedy is found 
in protecting the eyes from strong daylight by colored eyeglasses, 
in tonics, and nourishing diet. 
Snow-blindness may be regarded as analogous to the pre- 
ceding. CHAPTER XXI. 
THE EAR AND THE SENSE OF HEARING. 
The organ of hearing is divided into three principal parts — 
the external, middle, and internal ear. The external ear receives 
the sound; the middle mechanically transmits it; the internal re- 
ceives impressions and analyzes their quality, pitch, and intensity. 
Thus the three, by working together successively and harmoniously, 
complete, in the peripheral end organ, all that is required, so far as 
the material part is concerned, for the production of the external 
sensation of sound. 
The External Ear (A, Fig. 58) consists of two parts—the pinna, 
or auricle (1), and the auditory canal, or external meatus (2)—which 
collect, moderate, concentrate, and reflect inward the sounds fall- 
ing upon them. The pinna, or auricle, is the external skin and car- 
tilaginous framework. Its deep central concavity is the concha, 
and the lowest pendulous part the lobe. The irregular surface of the 
external ear is of some importance to hearing, as, by making 
the irregularities smooth, with wax or otherwise, though the canal 
be left free, the intensity of sound and its direction are apparently 
changed. In such a case the external smoothness reflects the 
sound-vibrations outwards, and, therefore, diminishes their intens- 
ity. The external ear is a sound condenser. Holding the hand in 
a concave position behind the ear increases the condensation, and, 
consequently, the intensity of sound. Its three muscles, named 
attollens, attrahens, and retrahens, keep it in position, and in man 
are seldom of sufficient size and strength to move the ear. In some 
animals these muscles are stronger, not only to gather more sound 
when listening, but also to relax or open the external part of the mea- 
tus to facilitate the entrance of the sound waves. Some animals, 
such as horses and cattle, have an advantage over man in this re- 
spect, as, when the sound-waves are too sharp or painful, or when 
swimming, they incline their ears backward, thereby closing the 
meatus. 
The External Auditory Canal, or meatus auditorius extcrnus 
(2), extends from the concha inward for about an inch, and ter- 201 
THE EAR AND THE SENSE OF HEARING. 
minates at the membrana tympani. In front of the concha is a prom- 
inence directed inward and backward, termed tragus (goat), cov- 
ered with hair, hence its name. At the outer part of the meatus 
are fine hairs and sebaceous glands, while deeper in the canal are 
small glands secreting a bitter substance (cerumen), called ear-wax, 
that catches dust and entangles insects, thus preventing their further 
ingress. When the external meatus is plugged with the secretion 
(cerumen), hearing is impaired; or, if the cerumen is lodged against 
the membrana tympani, vertigo, or dizziness, may be caused. The 
air in the external meatus, like air enclosed in any tube with an 
opening, increases sound by resonance; and as all tubes and vacant 
Fig. 58. 
Diagram of the ear. 
A, External ear. B, Middle ear. C, Internal ear. D, Internal auditory- 
canal (8), and auditory nerve (9). 
1, Pinna, or auricle of external ear. 2, External auditory canal. 3, Mid- 
dle ear, or tympanum. 4, Eustachian tube. 5, Vestibule of the internal ear. 
6, Semicircular canals of the internal ear. 7, Cochlea of the internal ear. 
8, Internal auditory canal. 9, Auditory nerve. 
spaces, according to size, have different tones when blown into, so 
the size and length of the external auditory canal modifies the 
tone. Consequently, it plays a part in the acuteness of hearing in 
different persons, one considering a certain sound disagreeably 
shrill, while another considers it very agreeable. 
The Membrana Tympani (a, Fig. 59) slopes obliquely from 
above downward and inward at the end of the external meatus (2). 
The slope presents a larger surface to the sound-waves. The vibra- 
tions of the membrane depend on its thickness and elasticity. It 202 
THE EAR AND THE SENSE OF HEARING. 
has no self-tone, as the malleus bone (&) in the middle ear (3) is 
attached to said membrane, acting on it as a damper, and is thrown 
into the same number of vibrations as the sonorous body. Normally, 
it vibrates more easily when lax, but when very tense acute hear- 
ing is impaired. The handle of the malleus bone, being thus at- 
tached, participates in the vibrations, and communicates the im- 
Fig. 59. 
Diagram of the middle and internal ear. 
B, Middle ear, or Tympanum. C, Internal ear. 
2, Portion of the external auditory canal. 3, Middle ear, or tympanum. 
4, Eustachian tube. 5, Vestibule of the internal ear. 6, Semicircular canals 
of the internal ear. 7, Cochlea of the internal ear. 8, Internal auditory ca- 
nal (meatus). 9, Auditory nerve. 10, Fovea hemispherica. 11, Auditory 
centre in the cerebrum. 
a, Membrana tympani. b, Malleus bone, c, Incus bone, d, Stapes bone, 
e, Fenestra ovalis. g, Stapedius muscle, h, Fenestra rotunda, i, Ampulla 
of the semicircular canal, j, Floor of the tympanum (middle ear). K, Ut- 
ricle of the vestibule. L, Saccule of the vestibule, m, Scala vestibuli. o, 
Scala tympani. r, Roof of the tympanum, s, Tensor tympani muscle. 
The dotted line in the vestibule (5) indicates the separating membrane be- 
tween utricle (K) and saccule (L). 
pulse to the incus (c), thence to the stapes (d) in contact with the 
membrane of the fenestra ovalis (e). The contraction and tension 
of the membrana tympani, in regulating or responding to sound, 
may he compared with the regulating power of the iris of the 
eye. The intensity of sound produces a reflex action, through the 
nervous system, to the tensor tympani muscle (s), which then pro- THE EAR AND THE SENSE OF HEARING. 
203 
duces more or less tension of the membrana tympani (a). The 
reflex by which the impressions are regulated is effected by a nerve 
from the trigeminus, through the otic ganglion. When the tensor 
tympani muscle contracts, the handle of the malleus is drawn 
inward, producing more or less tension in the membrana tympani; 
but when it relaxes, the membrane, by its elasticity, returns to its 
position of inactivity. This variation of tension is its accommodat- 
ing power to receive and transmit modified sound impulses, such as 
those of pitch, loudness, and quality. The membrana tympani is 
also the gate guard, permitting nothing to pass into the middle ear 
that would disturb the delicate mechanical action of the three little 
bones. The construction of both the external and middle ear is 
evidently designed for the propagation of sound, and its multipli- 
cation by resonance. 
The Middle Ear, or Tympanum (B, 3, Fig. 59), is a cavity, 
or space, between the membrana tympani (a) and internal ear (5), 
filled with air through the nasal cavity and Eustachian tube (4). 
It contains three very small bones—the malleus (b), incus (c), and 
stapes (d)—which, by their articulation with each other, establish 
communication and transmit sound-vibrations from the membrana 
tympani to the internal ear. The tympanum, therefore, from its 
position and office, is called the middle ear. The stapes covers the 
fenestra ovalis (e). The extent of the moderation of oscillation 
between the membrana tympani and fenestra ovalis may here be 
noticed. The passage of the oscillations through the three little 
bones, and the difference in size between the membrana tympani 
and the fenestra being as thirty to one, the extent of movement of 
the former is much modified; otherwise, it would burst the latter. 
The modification is effected by the leverage of said bones, the 
vibrations losing in extent but gaining in force. The manner in 
which sound is propagated through these bones is due partly to 
molecular action and partly to the movements of the same bones 
as a whole. The middle ear is lined with epithelium, being a con- 
tinuation of that of the nose, through the Eustachian tube. In 
the wall between the middle and the internal ear are two openings, 
or windows, termed fenestrse (e and h), each lined with a thin 
membrane. The larger is termed fenestra ovalis (e), leading to the 
vestibule of the internal ear, and is covered by the base of the 
stapes (d). The smaller opening is termed fenestra rotunda (h), 
and communicates with the cochlea. Both fenestrse lie in contact 
with the fluid endolymph in the internal ear (5). 204 
THE EAR AND THE SENSE OF HEARING. 
The middle and internal ear are situated within the temporal 
bone, which at that part is thick and hard—the 'petrous portion— 
so that the delicate and complicated structure inside may be the 
more fully protected. The space (3) of the middle ear is filled with 
air, thereby giving sound an acoustic effect. Its roof (r) separates 
it from the brain. The bone here is a thin plate, through which, if 
defective, inflammation of the brain may occur in case of abscess 
in the middle ear. Its floor (j) is also a thin plate of bone, separ- 
ating it from the jugular vein and carotid artery. Any accident 
to the head may burst the thin plate of bone and rupture the ar- 
tery or vein, producing haemorrhage into the middle ear, the 
blood escaping through the mouth, nose, and possibly through the 
external ear. Again, a person with a perforated membrana tym- 
pani may drown in water, though he be a good swimmer, the water 
entering the middle ear, and through the Eustachian tube into 
the throat. 
The Malleus Bone, or hammer (b, Fig. 59), consists of a head, 
neck, and three processes. The head articulates with the incus (c), 
the neck continuing to these processes. The first of these, termed 
gracilis, is thin, small, and long, to which is attached the levator 
tympani muscle, affording leverage to facilitate-the movements of 
this bone; the second, termed brevis, is pointed, as is the rest of the 
manubrium, and affords attachment for the tensor tympani muscle, 
lying in contact with the membrana tympani, pressing it slightly 
outward (concave), and acting as a damper in preventing after vi- 
brations. When waves of sound are too powerful and the damper 
not sufficient, then strong vibrations may produce pain sympathet- 
ically. The third process is long and pointed, termed manubrium 
or handle, attached to the membrana tympani, and taking part in 
its vibrations. The head of the malleus articulates with the incus 
by a loose joint, so that when its handle moves correspondingly 
with the vibrations of the membrana tympani the long process of 
the incus does not move therewith to that extent, as it is only two- 
thirds as long as the handle. Besides, the latter moves farther 
from its axis, and, therefore, the extent of vibratory movements on 
the stapes is considerably modified. They are, however, more 
powerful in its base on the membrane fenestra ovalis, in its move- 
ments to and fro. 
The Incus Bone, or anvil (c, at B, Fig. 59), consists of a body 
and two processes. Its body articulates loosely with the malleus 
bone, and its long process with the head of the stapes, and its THE EAR AND THE SENSE OF HEARING. 
205 
short one is attached to the margin of the opening leading to the 
mastoid cells, or cavities formed in the mastoid process by absorp- 
tion of bony tissue. 
The Stapes, or stirrup (d, Fig. 59), consists of a head, neck, two 
branches, and a base. The head articulates movably with the long 
process of the incus; the neck receives the stapedius muscle (g), the 
smallest in the body, originating just behind the fenestra ovalis, 
and holding the stapes in position on the membrane covering said 
fenestra. The two branches, or crura, of the stapes terminate at 
its base. The presence of three bones instead of one in the 
middle ear is to moderate the vibrations of the membrana tympani, 
so that said impulse of vibration may not injure the more delicate 
nervous structure in the internal ear and brain. These bones are 
covered with a membrane derived from the wall of the middle ear, 
and serve a twofold purpose—as a transmitter of sound, and for at- 
tachment of muscles. Adhesion, or anchylosis, at one or more ar- 
ticulations of the malleus, incus, or stapes, causes difficult hearing. 
The Muscles of the Middle Ear.—The tensor tympani 
muscle (s, Fig. 59) produces tension of the membrana tympani 
inward, its contraction not being continuous, but varying as the 
sounds differ, and by itself not under the control of the will. Nor- 
mally, it is excited reflexly through nerve impulses, similar to the 
iris of the eye. The laxator tympani muscle draws the malleus bone 
outward, relaxing the membrane. Both muscles are attached to 
the malleus, the tensor (s) to the manubrium, the laxator to the 
process gracilis. The stapedius muscle (g) originates at the eminentia 
pyramidalis, just behind the fenestra ovalis (e), and is inserted in 
the neck of the stapes, the base of which is thereby depressed and 
held in position on the fenestra ovalis, which is surrounded by an 
annular ligament, keeping the stapes in a more fixed position. The 
stapedius muscle, when active, moderates or prevents severe vibra- 
tory movements of the incus on the stapes. The nerve filaments 
of these muscles are from the facial nerve. 
The Eustachian Tube (4, Fig. 59) is about one and a half 
inches long. It establishes communication between the middle ear 
and nose. Disease in the nasal cavity may partially or entirely 
destroy the function of this tube for a time; for instance, by chron- 
ic catarrh, by thickening of the mucous membrane, pressure by ci- 
catrix or by tumor, producing partial or total deafness, either tem- 
porarily or permanently, the air in the middle ear vibrating then 
with difficulty, or perhaps not at all. In some cases the obstructive 206 
THE EAR AND THE SENSE OF HEARING. 
membrane may be remedied by the introduction of a Eustachian 
catheter ( 0 N ) through the nasal cavity, or of air with 
the Politzer’s bag. When the bag is used its nozzle is placed in 
the nostril, and wrhile pressing the bulb and forcing the air inti the 
middle ear, the effort to swallow must be made. The nasal orifice of 
the Eustachian tube is normally closed; but in the act of swallow- 
ing, or in other motions of the pharynx, it opens, and hence arises 
the necessity of swallowing during the injection of the air. When 
too much air remains in the middle ear hearing is dull, as it un- 
duly distends the membrana tympani, even to the extent of caus- 
ing pain. The act of swallowing, repeated a few times, will relieve 
this trouble if the tube be not compressed as above mentioned. 
The Eustachian tube is intended as an air-passage and outlet for 
mucus from the middle ear. In the effort at expiration, with the 
mouth and nose closed, air may be driven into the tympanum 
(middle ear), while the effort at inspiration under the same condi- 
tions withdraws it from that cavity, the air passing in and out 
through the Eustachian tube connecting the pharynx with the tym- 
panum, regulating thereby the pressure on the membrana tympani. 
Permanent occlusion of the tube is a common cause of deafness. 
The Internal Ear, or labyrinth (5, 6, 7, Fig. 59), consists of 
passages hollowed out within the thickest part of the petrous por- 
tion of the temporal bone, and is termed the osseous labyrinth. The 
membranous lining inside is called the membranous labyrinth. This 
latter, by its cavities and tubes, forms the vestibule, cochlea, and 
semicircular canals—all joining, and constituting in their entirety 
a closed sac in the internal ear. This membranous labyrinth is 
separated from contact with the surrounding bony structure by the 
liquor Cotunnii, a limpid fluid termed perilymph (14, Fig. 60). 
This fluid is secreted by cells in the wall of the membranous laby- 
rinth, and is finally carried away through the aqueduct cochlearis 
and taken up by the lymphatics. 
The internal ear is the most essential part of the organ of hear- 
ing. Its cavities and passages are divided into three portions, the 
vestibule (5, Fig. 59), semicircular canals (6), and cochlea (7), 
communicating with each other directly, and outwardly with the 
middle ear through the fenestra ovalis (e) and fenestra rotunda 
(h), also with the brain by the auditory nerve (9), which passes 
through the internal auditory meatus (8). 
The Vestibule (5, Fig. 59) is an irregular ovoid chamber, or 
central cavity, tilled with endolymph, and is about one-fifth of an THE EAR AND THE SENSE OF HEARING. 
207 
inch in diameter. It communicates not only with all parts of the 
internal ear, but outwardly, by the fenestras ovalis and rotunda (e 
•and h), with the middle ear (3), and inwardly, by the fovea hemi- 
spherica (10), with the internal auditory meatus (8). The wall or 
membranous lining of the fovea hemispherica has many perfor- 
ations, termed maculae cribrosas, for the passage of nerve filaments 
of the auditory nerve (9). The fenestrse of the middle ear form 
the only movable separating medium between the air contained 
therein (3) and the fluid in the labyrinth (5, 6, 7). The membrane 
covering the fenestra ovalis receives vibratory impulses from the 
stapes, which are communicated to the endolymph in the internal 
ear. The sonorous stimulus for oscillations of the endolymph may 
also be produced through the bones of the skull, by either placing 
a sounding body on the head, or a tuning fork between the teeth, 
when the ears are closed. In deafness, a sounding fork between the 
teeth may assist in diagnosis; if sound be perceived, it indicates 
that the internal ear, or labyrinth, is in good condition, in which 
case the trouble will likely be found in the middle or external ear. 
The vestibule communicates with the semicircular canals (6) and 
cochlea (7), and is divided into two sacs (indicated by dots) the 
utricle (k) and saccule (L); the utricle being the largest, and re- 
ceiving the membranous semicircular canals (6) by five orifices. It 
also communicates by a small Y-shaped tube with the canolis reu- 
niens forming the ductus endolymphaticus that passes through the 
osseous aqueduct, which terminates in a blind sac in the subarach- 
noid space. The saccule (L) is the smaller sac communicating 
by a small tube with the canalis reuniens and ductus endolymph- 
aticus. The utricle (k) and saccule (L, Fig. 60) have each an 
oval area termed macula acnstica (12), containing small bodies 
termed otoliths—crystals of carbonate of lime (12)—lying in the 
viscid endolymph in the utricle (k) and saccule (L). The otoliths 
are intermixed with otoconia, or ear powder—crystals more minute 
than the otoliths. The use of the otoliths and otoconia is to 
strengthen and divide equally the sonorous impulses in the endo- 
lymph; that is to say, they play the part of dirigents. If the sound 
makes a fine, gentle, and pleasing impression on the contents of the 
vestibule, then the impulse will be sent to the cochlea (like a gen- 
tleman into the parlor), where musical tones and enjoyable harmo- 
ny results. Should the sound make a harsh, disagreeable impres- 
sion, then it is relegated to the semicircular canals, resulting in dis- 
turbance and confusion. If the sound be of a mixed character, as 208 
THE EAR AND THE SENSE OF HEARING. 
from a wagon passing over a cobble-stone street, it is a noise. The 
vestibule, therefore, may be described as an enclosed porch, or hall 
(Vorhof), where all sound impulses are directed to their respective 
■compartments, according to quality. The nerve-flbrillae of the au- 
ditory nerve (9) supply the utricle (k), saccule (L), and ampullae 
(i), and also help to hold the membranous labyrinth in position. 
The wall of the membranous labyrinth consists of three layers—the 
outer, middle, and inner. The latter is formed of epithelial cells 
secreting the endolymph (liquor Scarpae), a limpid serous fluid which 
fills all the cavities and tubes of the membranous labyrinth, such as 
Fig. 60. 
Diagram showing the distribution of the auditory nerve-flbrillae 
within the vestibule. 
C, Portion of the internal ear. i, Ampullae of the semicircular 
canals. lc, Utricle of the vestibule. L, Saccule of the vestibule. 
5, Vestibule. 6, Semicircular canals. 7, Leading to the cochlea. 
9, Auditory nerve. 12, Otoliths, and Otoconia. 
I, One ampulla enlarged. 13, Bony wall. 14, Space between the 
bony and membranous walls, occupied by perilymph. 15, Wall of 
the membranous canal. 16, Internal portion of the membranous 
canal, occupied by endolymph. 17, Crista acustica having auditory 
nerve-fibrillse projecting into the endolymph within the canal. 
the vestibule, semicircular canals, and cochlea. The endolymph is 
the substance in which the true nerve-filaments pass to and fro (Fig. 
60), and into which the nerve endings for the sensation of hearing 
project (Fig. 62). It is renewed by the epithelial secreting cells; the THE EAR AND THE SENSE OF HEARING. 
209 
worn-out lymph and cells passing off through the arachnoid layer 
of the auditory nerve (9, Fig. 60) into the subarachnoid space of 
the brain. 
The Semicircular Canals (6, Fig. 60) are three osseous hollow 
windings surrounding the membranous semicircular canals. These 
canals are each about l-2Cth of an inch in diameter, and termin- 
ate in the utricle (k) by five orifices, one of which is common to 
two of the canals. Three of the apertures have enlargements at 
one end, termed ampullae (i, i,). Each ampulla has a projection, or 
tubercle, termed crista acustica (17), into which auditory nerve- 
fibrillae enter, and project, as it were, into the endolymph within 
the canal (16). These terminations of the nerve-fibrillse may prop- 
erly be termed equilibrium organ, as they regulate the equilibrium of 
the head, and its rotation as to rate and direction. A lesion of the 
horizontal semicircular canal disturbs this equilibrium, producing 
alternate lateral movements (right and left) of the head, often no- 
ticed in persons of advanced years, though hearing may not be in- 
terfered with. A lesion of the vertical semicircular canals causes 
up and down (nodding) movements of the head. Disturbance of 
all three semicircular canals produces loss of equilibrium in many 
directions (such as that in which the eyeball and lids participate), 
when the person may not be able to stand still, and may even fall. 
Such a disturbance may also be caused by weakness in the reflex 
centre of origin of certain auditory fibres in the cerebellum. In 
one instance lukewarm water gently injected into the ear of a 
healthy man of sixty to remove earwax produced such an effect on 
the nerve-fibrillse projections of the crista acustica that it caused 
him to stagger and fall on three different occasions, and blinded 
him for three or four minutes. The attempt to remove the wax 
with the curved end of a lady’s common hair-pin resulted simi- 
larly. 
When the eyes are bandaged and the body quickly rotated, equi- 
librium may be preserved for the first few turns, but it is soon lost, 
and a false impression of the relation of the person to his surround- 
ings takes place. In such a case the faculties of ascertaining proper 
position are either partially disturbed or entirely lost, and vertigo, 
giddiness, or dizziness, ensues. The revolving movement affects the 
endolymph in the ampullae of the semicircular canals, causing a dis- 
turbance on the nervous hair-like end projections in the ampulla?, 
by moving or floating them out of normal position. Giddiness 210 
THE EAR AND THE SENSE OF HEARING. 
may also be produced by impressions on the eye, for the cerebral 
area of sight and that of hearing are both in communication with 
the otic ganglion, and this, with the eye, corpora quadrigemina, and 
the membranous ear labyrinth. This accounts, too, for the loss of 
equilibrium and falling down, sometimes, of a person on suddenly 
beholding a shocking spectacle, as well as for the sympathetic 
connection—through the otic ganglion—between the membranous 
labyrinth and the eye, in certain diseases of either ear or eye. 
( Vide Auditory Nerve.) 
The Osseous Cochlea (7, Fig. 59; and Fig. 61) resembles a 
snail-shell. It is about a quarter of an inch in diameter at its base 
Fig. 61. 
Diagram of the cochlea. 
A, Nerve-flbrillse of the auditory nerve passing from the sacculus 
portion of the vestibule to and within the modiolus of the cochlea. 
B, Nerve-flbrillse emerging from the modiolus through the osseous 
spiral lamina (H). C, Terminations of nerve-fibrillse at the organ 
of Corti. D, Shape of the membranous cochlea. E, Helicotrema 
at the cupola of the cochlea. H, Indicating the osseous spiral lamina. 
K, Commencement of the scalse. 1, Natural size of the cochlea, 
about l-4th of an inch in width and height. 
(1, Fig. 61), and forms a spiral tube winding two and a half times 
around a central pillar termed the modiolus, and constitutes the 
anterior portion of the labyrinth, or internal ear. The central bony 
portion of the modiolus has minute channels for the passage of 
nerve-fibres and arteries (arteria centralis modioli). Both the mo- 
diolus, which terminates at the cupola (E), and the canal of the 
cochlea diminish in diameter from the base toward the apex, the 
canal being about half an inch in length. All along the modiolus 
is a projecting thin plate of bone termed osseous spiral lamina (6, 
Fig. 62), projecting about halfway into the canal, following its THE EAR AND THE SENSE OF HEARING. 
211 
windings and partially dividing it into two parts, or chambers (in- 
dicated at o and m Fig. 59, but more plainly at the transverse sec- 
tion of the one-half winding of the cochlea B, Fig. 62). The os- 
seous spiral lamina and the membrane of Reissner (1), and basilar 
membrane (3), subdivide the membranous canal of the cochlea in- 
to three canals, termed scalse, one of which (o, Fig. 59) is termed 
scala tympani (A, Fig. 62), communicating with the fenestra rotun- 
da (h, Fig. 59). In fact, it would open into the middle ear if the 
fenestra rotunda were not closed by a membrane. Another (m, 
Fig. 59) is termed scala vestibuli (A, Fig. 62), communicating with 
the vestibule (K, 5, Fig. 59). These two scalse also intercommunicate 
at the apex, or cupola of the cochlea (E, Fig. 61), through a small 
opening, the helicotrema. A third canal, or scala, is formed as 
follows: From the osseous spiral lamina (B, Fig. 62) three mem- 
Big. 62 
Diagram of the scalse and organ of Corti in the cochlea 
A, Transverse section of a one-half turn of the cochlea. B, Mo- 
diolus, or central stem of the cochlea. C, Scala media, or ductus 
cochlearis. D, An enlarged section of the organ of Corti. 
1, Reissner’s membrane. 2, Membrane of Corti. 3, Basilar mem- 
brane. 4, Cells of the organ of Corti. 5, Osseous laminae spans 
supporting the cells of the organ of Corti. 6, Osseous spiral lamina 
and indication of auditory nerve-fibrillae passing from the modiolus 
(B) through the osseous spiral lamina (6), to the cells of the organ of 
Corti (4). 
branes arise (1, 2, and 3), which gradually separate and cross the 
canal. The upper is called ReissneVs membrane (1), forming the 
roof of the third canal (C)*, termed scala media, or membranous 
ductus cochlearis; the middle membrane (2), which stretches through 
the greater portion of the scala media, and is called membrane of 
Corti; the lower membrane (3), forming the floor, is termed basilar 
membrane ( Vide Membrana Basilaris). The scala media, or ductus 
cochlearis (C), is about l-10th of an inch in diameter, and is of a 
triangular form. It is separated from the scala vestibuli by Reiss- 212 
THE EAR AND THE SENSE OF HEARING. 
ner’s membrane, and from the scala tympani by the basilar. The 
membrane of Reissner not only modifies the movement of the endo- 
lymph in the scala vestibuli, but also purifies the endolymph; for 
the ductus cochlearis (C) is filled with endolymph, which passes 
from the scala vestibuli through Reissner’s membrane by endosmo- 
sis, so that the ciliae (rods of Corti) float in the purest endolymph. 
The three scalae so formed—i. e., the scala vestibuli, scala tympani, 
and the ductus cochlearis—are each filled with endolymph. 
The Membrana Basilar is (3, Fig. 62) consists of fibrous 
bands stretching across from the osseous spiral lamina (B and 6) to 
a point termed crista basilaris on the bony wall opposite. The in- 
ner surface of this membrane is beset with about 3000 cells (4), 
each having ciliated (hair-like) projections, termed rods of Corti. 
The cells and their rods are remarkable in arrangement, running 
in a series from large to small, like pipes of an organ, as the duc- 
tus cochlearis diminishes in diameter. The grouping of cells which 
rest on the basilar membrane is termed organ of Corti. These cells 
are supported on this membrane by very delicate bony tissue lam- 
inae stretching across with it (5), like the spans of a bridge, giving 
support to the cells, in order that their hair-like projecting ciliae 
can be more readily impressed by the number and extent of vibra- 
tory impulses received through the endolymph in the scala media 
(C), into which they project. These ciliated projections (rods of 
Corti) are the external sense-organs of hearing. The nerve-fibres 
are sensory and belong to the auditory nerve (portio mollis), At 
the vestibule, the saccule fibres of this nerve (L, Fig. 60) enter and 
follow the minute bony canals within the modiolus, and issue there- 
from at regular intervals, passing along within the osseous spiral 
lamina, as indicated at (6, Fig. 62), and then enter the cells of the 
organ of Corti. The rods of Corti on the cells (4) have the power 
of responding to sounds of different pitch, according to the number 
of vibratory impulses passing through the endolymph of the duc- 
tus cochlearis (C), and are, therefore, the true external sense-organs 
of hearing. The long, thick rods at the base of this duct respond 
to deep bass notes, and the thin short rods at its apex to those of 
higher pitch. 
Sound is a quality perceived by the hearing arising from a cer- 
tain species of vibrations in the air, or in any other mass capable 
of being properly excited, and is caused by a sonorous or sounding 
body. Sound, therefore, is in the medium itself (be this medium 
a gas, fluid, or solid) that conveys it to the organ of hearing. A THE EAR AND THE SENSE OF HEARING. 
213 
Vibration is a change of position of particles of matter in quick 
succession; its equal interval of time being called the period of vi- 
bration. In the same proportion that an elastic medium facilitates 
the velocity of vibrations a dense one retards it, so that the greater 
the elasticity the greater the facility and rapidity of transmission 
of condensed and rarefied waves, or vibrations, through such me- 
dium. Again, the intensity of sound varies inversely as the square 
of the distance; so that a sound which has a certain intensity at a 
unit of distance will have only one-fourth the intensity at double 
the distance. Intensity likewise depends upon the amplitude of the 
vibrations, the density of the medium in which the sound is pro- 
duced, the direction of air currents, and the proximity of other 
sonorous bodies. A Wave-length is the distance between the 
two nearest particles of a medium in the same phase of vibration. 
This length bears a fixed ratio to the vibrations produced by the 
sounding body. The greater the number of vibrations per second 
the shorter the wave length. Sound travels through air at the rate 
of about 1100 feet in a second (about l-5th of a mile), while light 
travels about 186,000 miles per second. The extreme limits of reg- 
ular periodic vibrations of sound (tones) is between 30 and 30,000, 
but beyond these limits they cannot be perceived. Sounds have 
certain characteristics by which they are recognized as either mu- 
sical tones, or noise. When vibrations arrive at the ear with regu- 
larity of intensity, periodicity, and simplicity, a musical tone is 
the result, having three essential characters—loudness, pitch, and 
quality. Irregular and rapid non-periodic vibrations are the 
sounds called noise. Sound waves are refractive, as shown by the 
celebrated experiment of Sondhauss; and reflective, as beautifully 
illustrated in whispering galleries, especially in those of St. Paul’s, 
London, and of the famous gallery in the Mormon Temple at Salt 
Lake. The latter is elliptical, the slightest whisper at one focus 
being faithfully reproduced at the other. Musical sounds differ 
only in loudness, pitch, and quality. Loudness (intensity), as 
before stated, depends on the amplitude of the vibrations; ampli- 
tude being the distance, or height, of the crest of a wave from its 
axis (the imaginary central line drawn longitudinally through the 
wave). Pitch is the difference between a low and a high tone, 
depending on the number and rapidity of vibrations impinging on 
the ear in a second. Any two instruments giving forth tones of the 
the same pitch must produce the same number of vibrating wave- 
lengths in a given time; the more rapid these are, the higher the 214 
THE EAR AND THE SENSE OF HEARING. 
pitch. Quality, or, as it is also called, timbre or sound-clang, is 
dependent on neither pitch nor intensity, but upon the form or 
character of the vibrations. It is the peculiarity of tone which en- 
ables the listener to determine whether a tone comes from a violin, 
flute, zither, harp, piano, organ, bell, etc. All these different in- 
struments, in order to produce the same tone, must give off the 
same number of vibrations; at the same time, each has a peculiar 
quality, sound-clang, or timbre, by which one instrument may be 
distinguished from another. It depends really on what are called 
overtones. Overtones are sounds produced by a body vibrating in 
parts, these auxiliary vibrations being superimposed upon and ac- 
companying the fundamental tone produced by the vibration of the 
body as a whole. These compound wave-vibrations, striking the 
membrana tympani (in a manner somewhat similar to that expe- 
rienced on the finger from a dicrotic pulse), produce a sensation 
quite different from that produced by the fundamental tone alone. 
To pick out or distinguish these overtones requires generally the 
trained ear of the musician. As, however, the mechanism of the 
organ of Corti is not the same in all individuals, the nicety of dis- 
crimination of these overtones, be they manifested as harmonious 
or not, must vary in a corresponding degree. 
Resonance is the strengthening and prolongation of sound pro- 
duced by reflection or by reinforcement received from the vibrations 
of other bodies. If it be caused by reflection, the reflecting surface 
must be less than 112 feet distant from the sounding body, so that 
the direct and reflected sounds are blended. They cannot be heard 
separately, though they are mutually strengthened. If the dis- 
tance between the sounding body and reflecting surface be such 
that there is an interval between the reflected sound and the direct 
sound, we have what is called an echo. 
Sound waves occur in different ways, such as by the vibration of 
the air around a vibrating bell; a membrane, as the membrana 
tympani; through a hollow tube; through a solid, as the ossicles 
(bones) of the middle ear; or, through a fluid, as through the en- 
dolymph in the internal ear. Sound may cause an impression on 
the ear by a single wave, illustrated by a pistol-shot, or by a contin- 
uous succession of waves, as by a bell or piano-string. Sound 
waves passing through a tube do not disperse; consequently, they 
are transmitted to a greater distance with little loss of force. The 
sound motion of air particles is backward and forward in the line 
of propagation; not up and down, across that line, like water waves. THE EAR AND THE SENSE OF HEARING. 
215 
Hearing.—The fluid in the auricular labyrinth may be set in 
motion by sound-vibrations in two different ways: 1, By the base 
of the stapes in contact with the fenestra ovalis; and 2 . by vibra- 
tory motion communicated through the osseous walls of the laby- 
rinth. Ordinarily, it is effected through sound-waves entering the 
external meatus and impinging upon the membrana tympani. The 
vibrations are thence transmitted through the malleus, incus, and 
stapes of the middle ear to the membrane covering the fenestra 
ovalis, lying in contact with the endolymph of the utricle in the 
vestibule of the internal ear. The endolymph thus receives the 
impulse. Pressure on one side of a bladder filled with liquid nec- 
essarilly causes its other sides to bulge; but the membranous laby- 
rinth cannot yield, as it is surrounded by the osseous labyrinth. 
The movement, therefore, continues through the endolymph of the 
scala vestibuli(m, Fig. 59), and (A, Fig. 62), thus causing Reiss- 
ner’s membrane (1) to vibrate correspondingly; and producing 
more or less modified vibration of the endolymph in the ductus 
cochlearis (scala media, C). Again, the scala vestibuli, being in com- 
munication with the scala tympani at the cupola of the cochlea 
through the helicotrema (E, Fig. 61), the vibration of the endo- 
lymph extends through the scala tympani, which communicates 
with the fenestra rotunda, whose elastic membrane yields, and thus 
finally compensates for the bulging movements of the membrane 
covering the fenestra ovalis. The vibration of the endolymph of 
the scala tympani causes the membrana basilaris (3, Fig. 62) to 
vibrate correspondingly, thereby causing a more or less modified 
vibration of the endolymph on the opposite side of the ductus coch- 
learis (C). It may here be noticed that two organs—the mem- 
brane of Reissner (1), and the basilar membrane (3)—act as trans- 
mitters and modifiers of sound vibrations in the endolymph of the 
ductus cochlearis, which two functions are facilitated by the elas- 
ticity of the membrane covering the fenestra rotunda (h, Fig. 59). 
Thus, vibrations of the endolymph within the ductus cochlearis (C) 
are greatly modified, and sound is there resolved into its three prop- 
erties of intensity, pitch, and quality. The cilise, or rods of Corti, 
projecting into the endolymph of the ductus cochlearis, are thus 
enabled to become impressed. Each cell and its projecting rods of 
the organ of Corti differs in length and delicacy. Each rod of the 
three thousand is the terminal of an auditory nerve-fibrilla, and has 
the function of receiving the impression of a certain number of vi- 
brations, the impulse of which is transmitted to the auditory cen- 216 
THE EAR AND THE SENSE OF HEARING. 
tre in the cerebrum. To stimulate the terminals of the auditory- 
nerve the sound vibrations must have certain qualities—i. e., suffi- 
cient amplitude and duration; and, to excite a sensation of a con- 
tinuous musical sound, a certain number of vibrations must arrive 
at the ear in a given time—say, in one second. The membrane of 
Corti (2, Fig. 62) projects into the endolymph of the ductus coch- 
learis, and, when in repose, almost touches the rods. During its 
own vibration, however, it acts as a damper, permitting several or 
many rods to receive impressions more or less simultaneously. The 
cells of the organ of Corti (4) rest solidly on the basilar membrane 
(3), and their several rows of rods, or hair-like ciliae, are supported 
by the osseous spans (5). Now, if we suppose that a fundamental 
note or tone, say C, with 256 vibrations in a second, is appreciated 
by the appropriate rod, then its quality, or timbre, being a com- 
pound of vibrations, must be appreciated by as many different rods 
as there are differences of vibration in the compound. In this man- 
ner is established with facility impressions of intensity, pitch, and 
quality. The rods thus impressed, analyze the sound; a nerve im- 
pulse is transmitted to the auditory centre, and the external sensa- 
tion of musical sound follows. The auditory area, or centre, is at 
the first temporal or temporo-sphenoidal gyrus (E, Fig. 49), the 
destruction of which produces deafness of the opposite ear. The 
destruction of the entire gyrus in both hemispheres produces what 
the Germans call Seelentaubheit—deafness of spirits (soul-emotions). 
The sensations of sound, light, and other external sensations, do 
not take place in their respective areas, or centres, in the cerebrum, 
but, as we have shown, in the external organ itself. Normally, 
the sense of hearing may be improved in acuteness and delicacy 
by practice, as is illustrated in the experiment of the piano-tuner 
and musician. CHAPTER XXII. 
THE VOICE AND SPEECH. 
Voice, or the production of vocal sound, is a voluntary act; 
that is to say, it is under the control of the will. When tone is 
produced, air is expelled from the lungs through the air tubes and 
rima glottis with greater force. The rima glottis (1, Fig. 63), which 
separates the vocal chords (4, 4), is a small oblong aperture, wider 
posteriorly than anteriorly. 
Physically, for articulation, eight small yet distinct muscles are 
involved in each lateral half of the throat within the thyroid 
cartilage, five of which act on the vocal chords and three on the 
epiglottis. The former muscles are the thyro-arytsenoideus, crico- 
thyroid, crico-arytsenoideus posticus, crico-arytsenoideus lateralis, 
and arytaenoideus; the latter are the thyro-epiglottideus, aryteno- 
epiglottideus superior, and arytseno-epiglottideus inferior. 
The thyro - arytxnoid muscle, one on each side (2, Fig. 63) is the 
principal agent in drawing the thyroid cartilage forward and down- 
ward, and bringing the vocal chords (4, 4) nearer to each other. At 
the same time, these muscles swell inwardly, rendering the chords 
(the extreme edge of the mucous membrane of these muscles) tense. 
When the glottis is nearly closed, the crico- thyroid (6) and the 
posterior crico-arytxnoideus muscles (8) cause the margin of the 
chords to become concave. At the same moment the contraction 
of both thyro-arytaenoid muscles (2) effect a straightening of the 
extreme concavity of the chords (4, 4), which become tense and 
are set in vibration by the air passing outward. At first, a 
little air escapes without producing sound; then, at the margin 
of the concavity, two grayish-looking membranes (4, 4) appear 
stretched from end to end, and a sound, or tone, is produced. These 
two membranes (the chords) are just opposite each other, and are 
simply extensions of the mucous membrane on the anterior edge. 
Stretching makes them more grayish, hard, and solid. During 
their vibration they do not exactly touch one another. The 
muscular fibres of the membrane are extra strong. The thyro- 
arytenoid muscle (2) does not vibrate, but it effects the tension of 218 
THE VOICE AND SPEECH. 
the membrane on its anterior edge. The posterior crico-arytamoid 
muscles (8, 8) dilate the glottis. The crico-arytaenoid lateralis 
muscle (7) is inserted in the anterior margin of the arytsenoid car- 
tilage (9, 9), and acts to draw it forward. Paralysis of the latter 
muscle renders the voice harsh and deep, on account of the insuffi- 
cient tension of the chord resulting; but paralysis of the thyro-ary- 
tsenoid muscle (2) causes a total loss of the voice. The arytsenoideus 
muscle (11) is inserted into both posterior arytsenoid cartilages 
(9, 9), holding them together. 
Fig. 63, 
Diagram of the vocal chords and surrounding organs 
1, Kima glottidis. 2, Thyro-arytaenoideus muscle. 3, Thyroid carti- 
lage, constituting the pomum Adami. 4, Vocal chords. 5, Cricoid carti- 
lage. 6, Crico-thyroid muscle. 7, Crico-arytaenoideus lateralis mus- 
cle. 8, Crico-arytaenoideus posticus muscle. 9, Arytsenoideus carti- 
lage. 10, Superior cornu of the thyroid cartilage. 11, Aryttenoideus 
muscle. 12, Posterior continuation of (5), or cricoid cartilage. 13, 
Capsular ligaments connecting the arytaenoid and cricoid cartilages. 
14, Superior thyro-arytaenoid ligament. 
The thyro- and the two arytaeno-epiglottidei muscles are not shown 
in the diagram. 
The thyro-epiglottideus muscle arises anteriorly at the inner 
surface of the thyroid cartilage, just anterior and external to the 
thyro - arytsenoid muscle, and extends to the outer portion of the 
epiglottis. During vocalization it partially regulates the passage 
of air through the aperture by depressing the epiglottis. The 
superior arytaeno-epiglottideus muscle takes its rise from the apex 
of the arytsenoid cartilage, and extends to the layer of muscular 
fibres of the mucous membrane on the side of the epiglottis. 
During vocalization it assists in regulating the passage of air by 
constricting the superior aperture of the larynx. The inferior 
arytseno - epiglottideus muscle takes its rise from the inner lateral 
portion of the arytamoid cartilage just above the attachment of the THE VOICE AND SPEECH. 
219 
superior portion of the vocal chord, and extends to the inner and 
upper part of the epiglottis. During vocalization this muscle assists 
in regulating the passage of air by compressing the sacculus laryngis. 
When the tones of speech are produced, the air in contact with 
the vocal chords becomes alternately condensed and rarefied by the 
vibration of the chords, which oscillate rapidly, like the strings of 
a piano. Hence it is the condensed and rarefied air that sounds, 
and not the chords or string. ( Vide Sound in chapter on Hearing). 
The cavities of the larynx, pharynx, nose, mouth, and trachea form 
a compound resonating-tube. The muscles connected writh these 
cavities are acted upon through nerve-fibres, and in their action 
adapt themselves to the sounds and the pitch of the tone produced 
by the vocal chords. If one or more of these cavities or muscles 
be in an abnormal condition, resonance is imperfect. We can act 
at will on the vocal muscles to produce resonance, even below the 
chords; thereby producing a chest tone. In this the chords are not 
brought close together, and the vibration is communicated to, and 
perceptible at, the chest-wall; or, we can produce a head note (fal- 
setto), which is accomplished by causing the vocal chords to come 
closer together. Hence, the resonance in the trachea ceases, though 
in the posterior nares it is more pronounced. The limit of the hu- 
man voice lies between 100 and 1000 vibrations per second, embrac- 
ing about three octaves; though an expert in musical sounds may 
appreciate tones ranging from 30 to 38,000 vibrations per second. 
The note C of the middle octave on the piano vibrates about 256 
times in a second. 
The pitch of the tone depends on the tension of the marginal 
membrane of the chords, which may be likened to the stretching 
of the strings of a violin; but when the chords are brought in con- 
tact sound ceases. Again, the length of the vocal chords affects 
the tension, and so affects the pitch of the tone given forth. Men 
with a large thyroid cartilage (pomum Adami) have deej3 bass 
voices. The vocal chords of the female are about one-third shorter 
than those of the male. At the age of puberty the vocal organs 
grow rapidly, especially in the male, and the voice changes to a 
deeper bass tone. External pressure on the glottis causes a differ- 
ent sound to be emitted, even with the same pressure of air. Again, 
if the epiglottis be entirely open, no sound is produced, even with 
the strongest force of air; but as soon as the chords come close to- 
gether and air is forced between them, sound emanates. The closer 
the chords the less air is required to produce a tone of high pitch; 220 
THE VOICE AND SPEECH. 
but the looser and wider apart, the more air is required. Hence, a 
singer can execute an effective crescendo much easier, and without 
extra inhalation, in the higher notes than in the deep bass ones. 
In some individuals, when the chords are separated to the extent 
of about 1 millimetre, deep bass tones can be produced, but when 
farther apart no tone can issue. Voice is normally formed always 
in expiration. When a vocal sound is to be produced the chords 
are suddenly made tense and brought close to each other; the air 
is driven by forcible expiration between them, and the sound comes 
forth. The tone, pitch, and intensity of sound vary with the de- 
gree of tension of the chords and the force of expiration. 
Vocalization is accomplished in the larynx, but articulation is 
effected by the lips, tongue, teeth, and palate. Articulation is 
the utterance and joining together of the elementary sounds of a 
language by the appropriate movements of the vocal organs. It is 
regulated by efferent impulses through the facial and hypoglossal 
nerves, while vocalization is regulated by efferent and afferent im- 
pulses through the vagus—its superior laryngeal branch being the 
sensory (afferent) nerve of the mucous membrane of the larynx. 
The vagus also supplies efferent (motor) fibres to the crico-thyroid 
muscles. All the other muscles employed in phonation are supplied 
by efferent fibres of the inferior laryngeal nerve. 
Speech, may be defined as the utterance or articulation of words 
(sounds) to manifest concepts. Evidently, concepts may be 
manifested by gestures, nods, etc.; but more effectively by the voice 
(articulation). The Speech-centre is at the inferior portion of 
the third frontal convolution, near the bottom of the fissure of Syl- 
vius, in the left cerebral hemisphere. If, in the case of speech, the 
sensory and motor nervous centres, which must necessarily co-exist, 
as shown above, for co-ordinate action, become vitiated by disease 
or impaired from any other cause, speech must be defective. If 
the former centre is affected it produces sensory aphasia, there being 
a deficiency or suspension of the power of recalling the word, or of 
prompting the necessary nervous actions to pronounce it; if the lat- 
ter, there is motor aphasia, or loss of power to produce the proper 
muscular co-ordination necessary for articulation of speech. In 
some cases, a third, and even other motor centres are called into 
action. For instance, an organist having received a stimulus, 
through sight, from the notes of a piece of music lying before him, 
or from some other source, will sing, use his fingers on the upper 
key-board, and his feet on the lower, for the production of deep THE VOICE AND SPEECH. 
221 
bass notes. In this case even the centres of the cerebellum are 
called into action. 
In Sensory Aphasia the cerebral nervous centre is, in most 
cases, the first affected—possibly by embolism of the middle cerebral 
artery, or by other means of a mechanical nature. The subsequent 
softening of that portion of the brain, or haemorrhage, is the result 
of the embolism. In this case the motor reflex speech-centre, not 
receiving an impulse for action, remains in repose. 
Ataxic Aphasia is a loss of speech from inco-ordination of 
the necessary muscular movements of the throat and mouth. The 
muscles are not paralyzed, but their power is disturbed by the mo- 
tor speech reflex centre, preventing proper co-ordination of those 
muscles. Nerve-fibrillae pass from the cerebral centre of speech 
through the left crus cerebri and pons Varolii to the centres giving 
origin to the vagus, hypoglossal, trigeminus, and facial nerves in 
the medulla oblongata, thereby establishing its influence. In atax- 
ic aphasia the patient knows the word wanted, but fails in articu- 
lation from disturbance of co-ordination in the muscular move- 
ments necessary. He can write, because he knows the words, but 
cannot read aloud what he has written. It is most frequently pro- 
duced by lesions at or near certain centres of the medulla oblong- 
ata, or in an efferent nerve. 
Stammering, or difficulty in pronouncing certain letters or 
w'ords, is due to defective contraction of the diaphragm, causing 
spasmodic respiration during speech, thereby preventing air from 
passing through the vocal chords in a continuous flow. 
Stuttering is an obstruction of speech due to spasmodic neur- 
osis affecting co-ordination of muscles of the vocal apparatus, al- 
though respiration may be normal. CHAPTER XXIII. 
THE SKIN. 
The Skin (or integument) subserves four purposes, chiefly, viz.: 
1. It is the external covering, for the protection of the deeper parts 
of the body. 2. It is an excretory organ. 3. It is an absorbing 
organ. 4. It is the seat of the sense of touch. It consists of two 
principal layers—the epidermis and the dermis. 
The Epidermis (A, B, Fig. 64), an epithelial structure on the 
outer surface, consists of two layers—cuticle (A) and rete mucosum 
(B), each of which is divided into two layers. The Cuticle com- 
prises the stratum corneum and stratum lucidum; the Rete Muco- 
sum, the stratum granulosuvi and stratum Malpighii. The Strat- 
um Corneum consists of several layers of dry, horny, squamous 
epithelial cells, which limit superficial evaporation. The Strat- 
um Lucidum, beneath, consists of several layers of cells, clear 
and transparent, whence it derives its name. Below that lies the 
Stratum Granulosum, the cells of which secrete a substance 
termed keratin, — a function observed in cells in all situations 
where the result of the secretion turns corneous. Melanin is the color- 
ing matter—giving the white, brown, and yellowish color to the Eu- 
ropean, American, and Asiatic, respectively, and black to the negro. 
Pigment deposits, when found in the skin, as in the negro, are not 
formed in the epidermis, but carried there by leucocytes from the 
subcutaneous tissue; this is proved by the fact that white skin 
transplanted to a negro becomes black. The Stratum Malpi- 
ghii covers and dips down between the papilloe and rests on a del- 
icate basement membrane, forming the separating point between 
the epidermis (A, B) and the dermis (G, H). 
In the superficial layers—i. e., in the strata corneum and lucid- 
um—the cells are flattened, transparent, dry, and firm, being grad- 
ually formed and incessantly renewed from beneath by prolifera- 
tion of the rete Malpighii—successive layers approaching the free 
surface, and their contents being converted into a kind of horny 
matter. From the peripheral surface, the layers are constantly 
worn away, or desquamate in small flakes, called dandruff. When THE SKIN. 
223 
these two processes are accurately balanced in the phenomena of 
production and waste, the epidermis maintains its normal thick- 
ness; when, however, by repeated pressure, a more active cell-growth 
is stimulated, then the epidermis increases. This is noticeable in 
the hands of the laborer. The epidermis protects the sensitive and 
vascular cutis (true skin) from injury from without, and limits 
evaporation from the blood-vessels. This is proven by exposing to 
air the two hands of a deceased person. On one, if the epidermis 
be removed, the skin will become brown and dried up in the space 
Fig. 64. 
A, A, Superficial layers of the epidermis, or cuticle. B, B, Deep 
layers of the epidermis, or cuticle. (A and B constitute the epider- 
mis, or cuticle.) G, G, Papillae, resting on and forming the upper 
part of the corium of the derma, or cutis. H, H, Deep part of the 
corium of the derma, or cutis. (G and H constitute the derma, or 
cutis.) M, M, Fat cells surrounded by fibrous tissue, situated below, 
and not within, the derma. C, C, Sebaceous glands. D, Hair. 
E, Bulb of the hair. P, Papilla at the bulb of the hair. S, Nutri- 
ent artery. F, Erector pili muscle. I, I, Sudoriparous (sudorifer- 
ous glands), or sweat glands. L, L, Ducts of the sudoriparous 
glands. K, K, Orifices of the ducts of the sweat-glands. 
Sectional view of the skin. 
of a day; while the other, not so exposed, retains largely its natural 
moisture. Sunburnt complexion is due to an increase of col- 
oring matter; which in freckles accumulates in spots. As the soft 
epidermic layer is transformed into cuticle the pigmentary matter 
disappears from its cells. In the deeper layers the cells are large, 224 
THE SKIN. 
rounded, or columnar, and their contents soft and opaque. The 
under surface of the epidermis is accurately moulded upon the pap- 
illary layer of the derma (G), each papilla being invested, or cov- 
ered, by the epidermic sheath, which also sends fine tubular pro- 
longations into the ducts of the sudoriparous and sebaceous glands, 
and hair-follicles. 
The Dermis (G, H, Fig. 64) also consists of two principal lay- 
ers—the derma proper, or the superficial papillary layer (G), and 
the corium (H), the deeper layer. Together these layers constitute 
the cutis vera, or true skin (Lederhaut), which is composed of fibro- 
areolar, yellow-elastic, and white-fibrous tissues, making it tough, 
flexible, and highly elastic, to better protect the internal parts from 
injury. These tissues are interspersed with numerous blood-vessels, 
lymphatics, and nerves. 
The Derma.—Towards the surface of the derma the fibrous tis- 
sues become finer and more closely interlaced, and the most super- 
ficial layer is beset with numerous small conical, vascular, semi- 
transparent, flexible, and highly sensitive elevations of single and 
compound papillae arranged in two rows (G, Fig. 64). These are 
essential parts in the organ of touch. They are especially 
numerous on the areolte of the nipples, the palmar surface of 
the hand, and plantar surface of the foot. On the inner sur- 
face of the last joint of the fingers some papillfe stand in rows, 
others in groups, and are visible through the epidermis to the 
naked eye. According to Weber, in one square line of the palm of 
the hand there are 81 compound papilla?, with several points, and 
from 150 to 200 smaller papillae, arranged in almost regular rows. 
At the bottom of the furrows between the ridges are minute ori- 
fices—the ducts of sweat glands. The average height of a papilla 
is about l-100th of an inch, the base being about l-250th of an 
inch in diameter. Some papillae contain tactile corpuscles, others 
none. Those parts where tactile corpuscles in the papillae are most 
numerous are the most sensitive to touch, and vice versa. They 
contain one or more nerve-fibrillae; but those containing tactile cor- 
puscles are constituted almost entirely of nerve-fibrillae, -while 
those which have no tactiles are composed mostly of blood-vessels. 
The axis-cylinder of a nerve-fibre enters the corpuscle and wunds 
around spirally, while its sheath becomes identified with the outer 
wall of the corpuscle (Fig. 34). The tactile corpuscles are oval- 
shaped, and are situated in the papillae of the derma, covered by a 
sheath of epithelial cells of the rete mucosum, and together are THE SKIN. 
225 
considered to constitute what is really the organ of touch (organum 
tactus). The sense of touch is most highly developed where there 
are the most papillae containing tactile corpuscles. The Pacinian 
bodies, situated some distance beneath the derma, and not in it, are 
believed to be those organs by which pressure (a modification ot 
the sense of touch) is appreciated. This implies, however, a func- 
tional relationship between these bodies, mediately or immediately, 
and the organ of touch (Fig. 35). The papillae of the skin (Fig. 64) 
are well supplied with blood, receiving from the vascular plex- 
us in the derma one or more minute arterial twigs, that divide into 
capillary loops. The capillary veins also unite in the papillae, and 
pass out at their base. This abundant supply of blood in the pap- 
illae explains their swollen appearance and reddish hue when the 
circulation through the skin is unusually active. The highly de- 
veloped sensitiveness of a papilla depends on its tactile corpus- 
cle. (For the different phases of the sensation of touch, see Chap- 
ter XV.) 
The Corium constitutes the deeper layer of the skin (H, Fig. 64), 
and consists of a dense, strong interlacing network of oblique 
tensor (muscular) fibres, and various white fibrous and elastic tissues. 
(The latter become permanently blackened (argyria) in a person 
taking internally for a prolonged period doses of argentum nitrate.) 
The corium varies in thickness in different parts of the body, from 
a quarter of a line to a line and a half, being thickest in exposed 
regions, as that of the hand and sole of the foot, over the gluteal 
muscles and the patella, and generally thicker in the male than in 
the female. In the eyelids, it is very thin and delicate. The mus- 
cular membranous fibres, however, are most highly developed, and 
in many parts non-striated, as in the skin of the perineum, nipple, 
areola mammae, and extensor surfaces generally. 
The dermis, or cutis vera, is necessarily covered by the cuticle, 
or epidermis; for unless the very sensitive papillae were thus pro- 
tected contact with foreign substances would cause painful instead 
of the ordinary impressions of touch, as is proven by loss of tactile 
power in skin deprived of its epidermis. In parts where the cuticle 
is very thick, however, as on the heel, touch is imperfect or lost en- 
tirely. According to Kolliker, the thickness of the derma is from 
l-8th of a line to a line and a half. The skin is thinner on the 
front than on the back part of the body; thinner on the inner than 
on the outer side of the limbs, and very thin over flexures of joints 226 
THE SKIN. 
and eyelids. (Concerning touch, and sensation in general, vide 
tactile corpuscles, Pacinian bodies, and chapter on Senses.) 
Muscular Fibres of the Skin are voluntary or involuntary, 
the former, or striated fibres, being found on the head and neck 
only, where they radiate obliquely from the fibrous network of the 
derma (through which many mimic movements may be produced). 
The involuntary, or non-striated, muscular fibres are of three class- 
es— muscular membranous, hair erector, and oblique tensor of 
the corium — and act as important regulators in the functions 
of the skin. 
The Arrectores Pilorum muscles (F, Fig. 64; andm, Fig. 65) 
originate in the derma, and are partly attached to the hair-follicles. 
They also send down loop-shaped attachments to the elastic frame- 
work of the corium. During a slight contraction of these muscles, 
they relieve the sebaceous glands of their contents, and have no ef- 
fect on the hair-follicles; their severe irritation, however, causes 
traction on the hair-follicles, resulting in erection of the hair (notice- 
able on the back of an angry dog, or cat). 
The oblique tensor muscular fibres, with the elastic tissue, con- 
stitute, mainly, the corium. The elastic tissue exerts compression, 
and prevents the lymph-spaces from overfilling with the fluid of 
broken-down tissue, in which action the oblique tensors assist the 
compressing force, in response to the action of delicate nerve 
stimulus. The muscular and elastic framework establishes an 
inhibitory apparatus, distributing pressure, traction, and relaxa- 
tion equably, and influencing the movements of the fluids, nutri- 
tion, and the interchange of gases. 
Tension of the Skin.—Temperature exerts an influence on 
the muscular apparatus of the skin. A medium temperature causes 
moderate tension; a higher temperature, entire relaxation. In the 
senile skin, especially on the face and neck, the muscular fibres 
change and degenerate, causing the skin to wrinkle. 
The Subcutaneous Tissue beneath the corium (M, Fig. 64) 
is composed of connective tissue, fat and fat-cells filling up the 
spaces, acting as a soft.elastie pad, and having very little conduct- 
ing power; hence, it regulates to some extent the radiation of heat. 
(Vide Fat). It is blended, by strong interlacing fibrous bands, 
with the corium. 
The skin is provided with two kinds of secreting glands, sudori- 
parous (or sudoriferous), and sebaceous; and is furnished with two 
kinds of appendages, hair and nails. THE SKIN. 
227 
The Sudoriparous or Sweat glands (each a small coiled 
tube, or convoluted reddish body) are the organs by which a large 
portion of aqueous and gaseous materials are excreted, and are 
found in almost every part of the skin (I, Fig. 64). On the palm 
of the hand and sole of the foot, their orifices occur in regular lines 
between the ridges of the papillae; on other parts of the body they 
are scattered irregularly. The efferent duct (L), on leaving the 
gland, passes upwards in a spiral or cork-screw manner as far as 
the papillae of the corium, and lies between them. From there it 
passes straight to the cuticle, when it again resumes a spiral course 
and opens on the surface of the cuticle by a slightly oblique, valve- 
like aperture (K). The diameter of the duct (L) is about l-1700th of 
an inch. The glands are soft, of a reddish color, and more or less 
flattened by the pressure of one on the other. They are imbedded 
in connective tissue, and permeated by a network of capillaries. 
Their average size is about l-50th of a line, their number over two 
millions; their situation is in small pits in the deep parts of the 
corium, or below in the subcutaneous adipose tissue (I). The palm 
of the hand contains about 2800 orifices in each square inch. 
Krause calculated that the orifices of the sweat glands of the en- 
tire body represent an opening equal to about eight square inches 
of space. Those of the axilla (odoriferous glands of Horner) are 
among the largest, and secrete a peculiar odorous matter. Moll’s 
glands open into the hair-follicles of the eye-lashes. The peculiar, 
bitter, yellow, adhesive semifluid substance secreted by cells of 
ceruminous glands in the external auditory meatus is called ceru- 
men (earwax). Its function is the protection of the meatus and 
the membrana tympani from dust and insects. These glands 
are of a brownish color, and are simple modifications of (not differ- 
ing much in structure from) the ordinary sudoriparous glands. 
Sweat is not the product of the sudoriparous glands only. The 
intercellular passages of the epidermic cells open into the sweat- 
pores (ducts), by which the tissue fluid of the epidermis escapes 
externally. Consequently, sweat contains substances not secreted 
by sudoriparous glands (analogous to urine, which contains ingre- 
dients not formed by Malpighian bodies alone). The dog has su- 
doriparous or coil-glands, hut does not sweat, its sweat-pores open- 
ing into the hair-follicles. Sweat is usually formed so gradually 
that its watery portion escapes by slow evaporation, termed insen- 
sible 'perspiration. When it becomes profuse and collects in drops, 
it is called sensible perspiration. Sensible perspiration is the most 228 
THE SKIN. 
direct means of lowering the temperature of the body. Increased 
sweating is usually accompanied by dilatation of the cutaneous 
vessels; and, like other secretions, such as saliva, is under the re- 
flex influence of a special nervous centre in the medulla oblongata, 
acting through its nerve-fibres upon the cells of glands. Sweating, 
therefore, occurs not only when the skin is red, but also when pale. 
It occurs, besides, when the cutaneous circulation is languid, as 
when accompanying syncope, or immediately preceding death. 
On account of the presence of secreting glands, the orifices of 
which open externally, the skin becomes an excreting organ. The 
excreted fluid (sweat) consists of urea, extractive matter, carbonic 
acid gas, and water, the latter amounting to about two pounds in 
24 hours. The sebaceous secretion (sebum) is of a more oily 
nature, and is designed to keep the skin moist and pliable, and pre- 
vent a too rapid evaporation of moisture from the body. If, in a 
warm-blooded animal, these secretory processes are stopped—e. g., 
by varnishing the skin all over with an impermeable substance — 
the animal will die. 
The Sebaceous Glands secrete the Sebum, a suet-like fluid 
(C, Fig. 64). They are organs of a whitish hue, found in nearly 
all parts of the substance of the corium or subdermoid tissue, 
except on the palm of the hand or sole of the foot; they are most 
numerous in the integument of the scalp, face, nose, armpits, and 
anus. The largest glands of this class are the Meibomian, found in 
the eyelids. The tubes (ducts) of sebaceous glands are very small. 
They are filled with an opaque, white substance. One or more open 
generally into the hair-follicles, though sometimes on the surface, 
as on the labia minora, prepuce (Tyson’s glands), and red margins 
of the lips of the mouth. 
Secretions of the sebaceous glands, hair-follicles, and epidermic 
intercellular matters passing into hair-follicles, become so intimately 
intermingled as to form a single homogeneous product. It consists 
of oily and extractive matter, caproic and butyric acids, and cast- 
off epithelial cells, the former of which gives it its peculiar odor. 
The purpose of the sebaceous secretion is to keep the skin moist, to 
moderate evaporation, and to guard it from the effects of the long- 
continued action of moisture. The secreted product is similar to 
that on the body of the foetus in utero. It must, therefore, be 
reckoned among the excretions. What part it has in the process of 
purifying the blood is unknown. Sebaceous glands often contain a 
parasite termed acarus folliculorum. Sebaceous matter, when first 
secreted, is fluid in consistency; but in the ducts often hardens, as THE SKIN. 
229 
on the nose, where it can be squeezed out in a wormlike form—the 
so-called comedo. 
The Appendages of the Skin—the hair and nails—are mod- 
ifications of the epidermis. 
Hair (D, Fig. 64; and A, Fig. 65).—The skin (except that of 
the outer surface of the eyelids, palms of the hands and dorsal sur- 
faces of the third phalanges, and soles of the feet) is covered with 
hair. The hair may be fine and delicate, or coarse and strong. 
The individual hairs are situated in depressions of the skin termed 
hair - follicles (G), and extend obliquely into the deepest layer of 
the dermis, or into the subcutaneous tissue, and have at the bottom 
Fig. 65. 
Diagram of transverse and longitudinal sections of a hair in 
hair - follicle. 
1, Medulla, or pith of the hair. 2, Cortex, or cuticle layer of the 
hair. 3, Hyaline membrane between the hair and follicle. 4, Hux- 
ley’s layer of internal lining of the hair-follicle. 5, Henle’s layer of 
internal lining of the hair-follicle. 6, Middle layer of the follicle. 
7, Fibrous layer between the middle and external layers. 8, Exter- 
nal layer of the follicle, with blood-vessels. 9, Blood-vessels. 
A, Hair. B, Bulb. C, Papilla. D, Hyaline membrane and inter- 
nal sheath of the follicle. E, Middle layer of sheath of the follicle. 
G, External layer of sheath of the follicle. S, Sebaceous glands. 
m,m, Erector pili muscles. 
small papillae (C), from the surface of which the hairs take theii 
rise. The wall of the follicle is lined continuously with squa- 
mous epithelial cells (4, 5,6, Fig. 65), resting on a layer of the fibrous 230 
THE SKIN. 
connective tissue (8 and G) in contact with the surrounding 
corium. The follicle appears simply as a deep depression in the 
surface of the integument. The wall of the follicle is generally 
channeled by one or more ducts of sebaceous glands (S), some of 
which discharge into the hair-follicle, and others on the free 
surface of the skin. 
The hair grows from a papilla (C), at the bottom of the follicle, 
the papilla supplying the material for its nourishment. It is lined 
with a layer of squamous cells. This lining makes a turn up- 
ward at the side of the papilla, so that the horny cell layer of 
the hair and follicle face each other. Their union is prevented 
by a layer of fusiform cells which interposes a transparent, 
glossy, hyaline membrane between, (3, D). For reasons stated, 
the outer layer of hair, consisting of everted squamous scales, is 
termed the cuticle of the hair (2). This cuticle surrounds a 
single layer of non-nucleated, flat, elongated, homogeneous cells, in 
the center of which is the medullary space, sometimes filled with 
pith, but generally hollow. 
The root of the hair rests upon the papilla, the cells of which 
form successive layers whereby the hair grows towards the surface 
of the skin by gradually rising within the follicle. The hair and 
follicle lay obliquely, but the erector pili fibres (m) extend angu- 
larly from the surface of the papillary layer of the dermis to the 
follicles, so that during contraction they pull on the follicles, caus- 
ing the hair to stand erect on the skin. When a hair is broken off 
by pulling, it grows again; but if the root below be extracted (bulb 
B), the epithelial wall along the follicle also becomes injured, and 
the hair will not be reproduced. Hair is shed in certain animals 
periodically by being lifted off from the papilla through the con- 
tractive, or pinching, force of the dermis on the hair-follicles. As 
soon as the pressure from below upward is lessened the new hair 
commences to grow, pushing the old outward, the old hair falling 
off when the new reaches the surface. In the human scalp, in old 
age, the fibres of the dermis gradually contract, become hard, and 
produce pressure on the hair follicles; in consequence thereof the 
hair-stem becomes thinner, assuming the lanugo (woolly) form; or, 
if the contraction and pressure be complete, the hair papillae at- 
rophy, the follicles permanently collapse, and the hair growth is 
destroyed. Again, during a severe illness, the old papillae may 
dry up and the hair become loose. When new papillae form new 
hair grows, gradually pushing the old out of the follicles. THE SKIN. 
231 
Gray Hair.—When the pigment formation in the cortex be- 
comes defective, the hair turns gray, as in old age; or if the me- 
dulla, or pith, become defective, the center of the hair becomes 
filled with air, giving it a silvery appearance. 
Blood-vessels, Nerves, and Lymphatics.—The hair- 
follicles, sudoriparous and sebaceous glands, are surrounded by 
areolae, or spaces filled with adipose tissue. These spaces are the 
channels through which the vessels and nerves are distributed to 
the more superficial strata of the corium and papillary layer. The 
dermis is supplied with numerous lymphatics. The blood-vessels 
form two systems, superficial and deep. The superficial supply 
the papillary layer; the deep, the fatty tissues, hair-follicles, seba- 
ceous and sudoriparous glands. 
A Haemorrhage in the skin does not rise above its level. It 
may take place in one of three ways:—1. Rupture of vessels from 
external violence or internally by increased blood-pressure, result- 
ing in effusion into the integument. 2. In vascular degeneration 
in disease of the walls of vessels. 3. By transudation of blood 
through the vascular walls. Bluish-red, greenish-yellow, and yel- 
lowish-brown spots, are produced by the progressive involution of 
the stagnated blood. 
The loss of water through the skin in a healthy adult in 24 
hours by sensible perspiration, adding the carbonic acid gas, salts, 
and other excretory matter, is about one and a half to two pounds; 
so that in this time there may be a loss of l-28th of the weight of 
the body by urine, respiration, and perspiration. 
The toughness, resistance, flexibility, and elasticity of the skin 
admirably fit it for protecting the organs beneath. The horny lay- 
er of the epidermis, hair, and subcutaneous fat serve for the re- 
tention of the natural warmth of the body. The skin is also an 
organ of absorption of substances in solution sufficiently dilute to 
penetrate the horny layer of the epidermis. They are taken up by 
the cells and ducts of glands, absorbed by capillary veins and lym- 
phatics, and pass into the general circulation, acting in the same 
manner as if taken internally. Water and fluid or semifluid forms 
of nourishment, especially milk, may be administered through the 
skin; also many medicines, as by inunction or in solution, except 
strong astringents, which are difficult or impossible of absorption. 
While a strong solution of an alkali, especially soda, hardens the 
epidermic cells, a weak solution softens and swells them. 
The Nails on the fingers and toes consist of horny, homogene- 232 
THE SKIN. 
ous cells resting on a basement layer, and ran posteriorly and lat- 
erally in a groove. The posterior white part, termed lunula, com- 
prises the nail-roots. The growth of the nail is forward from the 
matrix, or posterior aspect, extending from the extreme posterior 
portion of the roots to the anterior border of the lunula. The 
cells of the matrix secrete the nail substance, which deposits in 
layers. The new secretion gradually pushes the previously formed 
part forward. The thickness of the nail-body is the same from 
the lunula to the anterior projecting edge. The posterior groove 
in which the nail-roots are lodged prevents growth backward. CHAPTER XXIV. 
THE KIDNEYS. 
The Kidneys are two glandular organs situated in the abdom- 
inal cavity, one on each side of the vertebral column. They are 
held in position by the entering and departing vessels and by a 
quantity of surrounding fat, somewhat firm. The anterior portion 
of the right kidney lies close to the liver, and to the descending 
part of the duodenum and ascending colon; while the anterior por- 
tion of the left is in close relation with the spleen, pancreas, stom- 
ach, and descending colon; only the surrounding fat separating it 
from these organs. The kidney is a smooth, dark-red, compressed 
oval body, with a hilum (notch) on the inner surface in connection 
with an anterior sinus (cavity), where the renal vessels, nerves, and 
excretory duct have their entrance and exit (5, 6, and 7, Fig. 66). 
The ordinary size of a kidney in the adult is about four inches in 
length, two in width, and one in thickness. It weighs about five 
ounces. Its external portion, termed the cortical substance (1), is 
about one-fourth of an inch thick, and constitutes about three- 
fourths of the gland. It consists of a multitude of glomerules 
(Malpighian bodies), nerve-fibres, capillary blood-vessels, and lym- 
phatics, in connection with the uriniferous tubules. Between these 
organs is interposed a small quantity of very fine areolar tissue. 
The glomerules give it a granular appearance. The central portion 
of the kidney is the medullary substance, and consists principally 
of straight uriniferous tubules, arranged in a series of various 
sized cones forming the renal pyramids (2), from ten to fifteen in 
number, and extending from the papillae (3), through the medul- 
lary substance, to near the surface of the cortical structure. The 
apex of the pyramid-shaped arrangement of uriniferous tubules 
forms a nipple-shaped point at the pelvis, and is termed a 
renal papilla (3). The uriniferous tubes are the channels through 
which the urine flows from the cortical substance (1) into the pel- 
vis (4)—i. e., the funnel-shaped upper portion of the excretory duct, 
or ureter (5). Both the pelvis and the ureter are lined with mu- 
cous membrane, containing transitional epithelial cells, sometimes 234 
THE KIDNEYS. 
intermixed with columnar epithelial cells. The cavity of the pel- 
vis is subdivided into four or five portions, called calyces (small 
cup-like membranous canals). Into each calyx three or four re- 
nal papillae project, so that the urine dripping from the uriniferous 
tubules, and through the papillae, is received by the calyces, con- 
veyed to the pelvis, and descends through the ureter (5) into the 
bladder. In this manner the calyces, pelvis, and ureter, together, 
form the excretory duct for the urine. 
The kidneys are well supplied with blood-vessels, nerves, and 
lymphatics, held in place by connective tissue. The renal artery 
(6), is short and thick, proceeds directly from the descending aorta, 
and supplies the arterial blood; which, having thus considerable 
force, easily penetrates the kidney and communicates with the 
Fig. 66. 
Diagram of the kidney. 
1, Cortical substance. 2, Renal pyramid. 3, Renal papilla. 
4, Renal pelvis. 5, Excretory duct (ureter). 6, Renal artery. 
7, Renal vein. 
glomerules, uriniferous tubules, and veins. The capillaries of most 
of the arterial and venous branches ramify in the cortical sub- 
stance, forming the glomerules. 
A Glomerule (Malpighian body, or corpuscle), is a dense clus- 
ter, or round, ball-like mass, formed by capillary arteries, veins, 
and the endings of nerve-filaments, enclosed by a capsule (Bow- 
man’s capsule, A and B, Fig. 67), about l-144th to l-80th of an 
inch in diameter. This capsule is the commencement of the urin- 
iferous tubule (E). The capsule and tubule consist of basement 
membrane, lined with glandular epithelial cells. The tubules are THE KIDNEYS. 
235 
convoluted, and unite as they pass along to form the pyramids 
(2, Fig. 66), which at the cortical portion may consist of hun- 
dreds of tubules, while at the opening of a papilla (3) they are few 
in number. 
The glomerules, or Malpighian bodies, cause the cortical sub- 
stance to appear granular. Into each glomerule, arterial and ve- 
nous branches enter (1, C and D, Fig. 67). The function of the 
glomerule is to separate the superfluous water from the blood. This 
Fig. 67. 
Diagram of a glomerule, or Malpighian body, of the kidney 
1, Longitudinal section of a glomerule. 2, The glomerule intact, 
being completely surrounded by its capsule. A and B, Bowman’s 
capsules. 0, C, Branch of the renal artery. D, L>, Branch of the renal 
vein. E, 1. Longitudinal section of a uriniferous tubule. D and E, 
2, Indicating the network of a uriniferous tubule and its capillary 
blood-vessels. 
is, possibly, simply a dialytical, or straining process, forcing watery 
parts of the blood from the glomerule into its surrounding 
cavity. The capsules (A and B) and the uriniferous tubule (E,E) 
are lined with glandular epithelial cells, which absorb, separate, 
and secrete from the blood various elements forming urea, uric acid, 
creatine, and the inorganic salts, such as chloride of sodium and. 
phosphate of soda. The cells perform the functions of absorption, 
separation, and secretion, and transmit the saline elements, in 
solution, to the interior cavity of the capsule and. uriniferous tubule 
(E, Fig. 67), where the aqueous portion coming from the glomer- 
ule unites with the saline solution and passes into the pelvis as urine. 
The arrangement of the convoluted portion of the tubules (D, E) in 
the cortical substance is such that it forms a network similar to 
that of capillary blood-vessels; so that within the cortical substance 
the network of both are so closely interwoven that the secreting 236 
THE KIDNEYS. 
epithelial cells absorb or separate the salts from the blood with fa- 
cility. The tubules of the network of the cortex are winding in 
their course—i. e., they descend and partially return many times, 
forming loops (2, D and E), called Henle’s loop-tubes. On nearing 
the papillae the tubes discharge into one another, their number be- 
coming smaller in the formation of the pyramids, finally passing 
in a straight line to the papillae. 
The function of the kidneys is to separate certain matters from 
the blood that would be injurious to the system if retained. The 
urine, therefore, for the most part, consists of waste matters. Its 
fluid and solid constituents bear no constant ratio to each other, 
the proportion of fluid present depending upon the amount of 
fluid taken with the ingesta, and on arterial capillary fullness and 
pressure; while the amount of solids contained depends on the kind 
of food taken and previous waste of tissues. The Malpighian 
bodies and uriniferous tubules are the most essential organs in the 
kidneys for the performance of their function. 
Lymphatic capillaries are distributed throughout the parenchy- 
ma of the kidneys. 
The nerve-fibres are derived from the renal plexus. They carry 
impulses for sensory, vaso-motor, vaso-dilator, and for secretory 
functions. 
The Urine is a clear, amber-colored fluid, normally of an acid 
reaction; average specific gravity, 1020. Its composition is:— 
Water 950.00 
Nitrogenous organic 
substances. 
Urea 26.20 
Creatine 0.87 
Sodium and potassium urates 1.45 
Sodium and potassium hippurates.... 0.70 
Mucus and coloring matter 0.35 
Sodium biphosphate 0.40 
Sodium and potassium phosphates 3.35 
Lime and magnesium phosphates 0.83 
Sodium and potassium chlorides 12.55 
Sodium and potassium sulphates 3.30 
Mineral salts. 
1000.00 
The quantity of urine secreted daily is about 1400 cubic centi- 
metres (about 48 ounces). It is discharged from four to six times 
during that period. Should the secretion of urine become completely 
suppressed, the elements of urea remaining in the blood would soon 
exert a poisonous effect, especially on the nervous system. This 
usually, and speedily, results fatally. If at one time of the day 
urine has a specific gravity of 1012, and at another 1028, the KIDNEYS. 
237 
variation may be accounted for by the different kinds of food taken, 
and may be considered normal; but either 1012 or 1028, if long 
continued, would be an indication of abnormal conditions. 
Urea constitutes the characteristic and most important solid in- 
gredient of urine. It crystallizes in white, glistening, streaked, four- 
sided prisms; or, when very rapidly crystallized, it forms in small, 
white, silky needles (Fig. 68). Its taste is bitter, like that of salt- 
petre. Urea is an amide of carbonic acid; for urea, when added to 
water and heated to 200° in a tightly closed tube, breaks up into 
carbonic acid and ammonia. Generally, some of the mucus of the 
Fig. 68. 
Diagram of appearance of Urea when Crystallized. 
bladder is voided with the urine and acts as a ferment; so that in 
a few days, at ordinary temperature, urine is rendered ammoniacal. 
The normal stimulus to micturate is the sensation excited by the 
action of the urine on the mucous membrane of the bladder. An 
impulse is forwarded through afferent (sensory) nerve-fibres in 
communication with the hypogastric plexus to the nervous centre 
of micturition in the spinal cord at the fourth lumbar vertebra. 
This centre reflexes the impulse by sending an efferent (motor) 
impulse through nerve-fibres in communication with the sacral 
plexus to the sphincter vesicae, which dilates, thus allowing the 
urine to flow out through the urethra. The power of the will exerted 
on this centre excites a similar reflex motor impulse to micturate; 
or the power of the will may restrain the reflex action, though for 
a limited time only. The average amount of urine excreted by an 
adult in twenty-four hours contains about 33 grammes (500 grains) 
of urea; and from about seven to ten grains of uric acid. An 
artificial urea may be obtained by the action of ammonia on ethyl 
carbonate; or by the action of ammonia on carbon oxydichloride; 
also by the action of heat on ammonia carbamate and carbonate. 
Urea forms approximately one-half of the entire quantity of the 
solid (saline) ingredients of urine. The quantity of urea in the 
urine depends upon the rapidity of tissue decomposition, espe- 238 
THE KIDNEYS. 
cially nitrogenous, and the kind of food taken. It is increased by 
the consumption of animal food and by increased muscular activi- 
ty; but decreased by a vegetable or non-nitrogenous food diet, such 
as starch, sugar, and fat. The materials entering into the formation 
of urea are, therefore, in the tissues and in the blood; but urea, as 
such, does not normally exist therein, being formed completely only 
by the secreting cells of the capsules (Bowman’s) enveloping the 
Malpighian bodies, uriniferous tubules, and the ducts of the seba- 
ceous glands. In a pathological condition, when the Malpighian 
bodies and tubules of the kidneys, or the ducts of the skin, become 
obliterated, the urea already formed in these organs becomes ab- 
sorbed by the lymphatics, and may be carried into all fluids and 
parts of the body. Urea is a secreted excrementitious compound, 
which has to be speedily removed, or its accumulation in the sys- 
tem exerts fatally paralyzing effects, especially on the nervous 
centres. 
From 50 to 60 grammes of solids are discharged daily with the 
urine by the healthy adult. When organic salts, such as acetates, 
lactates, and tartrates, are taken, they are changed in the blood in- 
to carbonates, and the urine becomes alkaline. It is claimed that 
about 10 to 18 grammes of sodium acetate, taken internally, causes 
alkalinity of the urine within twrenty minutes. The sodium and 
potassium urates are also increased (like urea) by nitrogenous food, 
the result of alkaline bases with nitrogenous mineral acid. Any 
substance that will neutralize an acid is called a base, and a com- 
pound of an acid and a base is termed a salt. In the urine some 
of the alkaline sodium phosphate is replaced by acid sodium bi- 
phosphate, which gives urine the property of reddening blue litmus 
paper, although urine contains no free acid. 
Uric acid is combined with sodium and ammonium urates, the 
sodium predominating. Uric acid does not exist in the urine 
in a free state, but in combination, principally as sodium urate, 
and is believed to combine with some of the sodium, the base 
of sodium phosphate. The remainder of this salt being con- 
verted into acid sodium bisulphate, the urine thus acquires an 
acid reaction. As almost any acid added to urine decomposes 
the urates, uric acid is set free and crystallizes (Fig. 69). By 
using largely for a time fruit and vegetables containing tar- 
trates and citrates of the alkaline bases, the urine becomes 
alkaline from the presence of alkaline carbonates, since the 
conversion of the tartrates and citrates into carbonates takes THE KIDNEYS. 
239 
place in the blood. Continued mental labor increases the alkaline 
phosphates, while the earthy phosphates are increased by nervous 
diseases, the urine, having an acid reaction, holding the earthy 
phosphates, such as phosphates of lime and magnesium, in solution. 
Fig. 69. 
Diagram of uric acid crystals. 
The Bladder is well supplied with nerve-fibres, blood-vessels, 
and lymphatics. The nerves are branches from the sacral plexus 
of the spine and hypogastric plexus of the sympathetic. 
Incontinence of Urine is often due to diminished sensitive- 
ness in the mucous membrane of the bladder or sphincter vesicae, 
and the urine is evacuated unconsciously. 
The Retention of Urine in old people is generally due to the 
hardening of the prostate gland, which presses upon the urethra. 
The efferent (motor) reflex impulses then have diminished power 
to dilate the sphincter vesicae. 
The general opinion is “that the kidneys in the early period of 
foetal life are very small and imperfect, their functions being per- 
formed by the Wolffian bodies, two organs analogous to the 
kidneys in structure. These afterwards become atrophied and then 
disappear. The kidneys grow rapidly, making their first appear- 
ance just behind the Wolffian bodies, and take their place at the 
end of the second month of foetal life.” It seems more likely, how- 
ever, that the Wolffian bodies noticed in early foetal life develop 
into the suprarenal capsules. That these bodies ever performed 
the functions of the kidneys is rather problematical, as it has not 
been proven that the kidneys are active, any more than are the 
lungs or the intestines of the foetus. 
Disease of one or both kidneys may affect the body to such 
an extent that excrementitious matters accumulate in the blood, so 
contaminating it as to render it unfit to carry on the vital processes 
on which the activity of the brain depends. This results in deli- 
rium or unconsciousness. 
During health the cells lining the uriniferous tubules contain 240 
THE KIDNEYS. 
very small oil-globules. In the pathological state called Bright’s 
disease they are more numerous and very much enlarged, causing 
pressure on the neighboring capillary veins and lymphatics, and 
obstructing the circulation. The reason of the great pressure on 
the capillary arteries is that the blood flows direct from the abdom- 
inal aorta through the short and thick renal artery; and, meeting 
with obstruction in the veins and lymphatics, the albumen in the 
serum of the blood exudes with the water and salts, and so gets 
into the urine. 
In acute inflammation of the kidneys (nephritis) there is a deep- 
seated pain in the back, on one or both sides, aggravated by press- 
ure or sudden change of position. The urine becomes scanty, 
highly colored, albuminous, or bloody; and, if allowed to stand, de- 
posits pus and sediment. The patient is more or less feverish, gen- 
erally troubled with rigors, nausea, vomiting, and constipation. 
In chronic inflammation the symptoms are milder. In both acute 
and chronic inflammation, the blood may become contaminated, 
as in Bright’s disease, from the want of proper purification by the 
kidneys, when many secondary affections may arise. 
The Suprarenal Capsule is a small, flattened, glandular 
body of a yellowish color, weighing from one to two drachms, and 
belongs to the class of ductless glands. It consists of a corti- 
cal and medullary substance, with numerous blood-vessels and 
nerves, and is located over the anterior and upper portion of each 
kidney. Dr. Addison, of Guy’s hospital, London, first pointed out 
that a certain disease of the suprarenal capsule or capsules is as- 
sociated with a deposition of pigment in the skin, which assumes 
a deep bronze color. Addison’s disease is sometimes termed supra- 
renal melasma, or bronze-skin disease, and is characterized by gen- 
eral debility, loss of muscular power, remarkable weakness of the 
heart’s action, extreme prostration, breathlessness on the slightest 
exertion, dimness of sight, functional weakness and irritability of 
the stomach, a peculiar and uniform discoloration of the skin of a 
brownish olive-green hue—like that of a mulatto. The morbid 
changes in the capsules are of a soft deposition, degenerating into 
a yellowish-white opaque matter, followed by abscess, or drying-up 
into a chalky mass. The only probable aid is nourishing food and 
tonics to keep up the general health. The progress of the disease 
is slow, extending over a period of from one to about five years. 
Then death follows by heart failure, as if its natural stimulus, the 
blood, had ceased to act. CHAPTER XXV. 
THE MUSCULAR TISSUES. 
The fully developed muscular tissues consist of two distinct 
kinds of textures: 1, Striped fibres; 2, non-striped fibres. Muscu- 
lar tissue composed of striped fibres is called striated muscle; that 
composed of non-striped fibres is called unstriated muscle. Re- 
specting the function of these two kinds of muscle-tissue, no strict 
classification can be made. In general, however, it may be said that 
the striated muscles are those that perform functions pertaining to 
animal life, that they are under the control of the will (except 
the muscular structure of the cardiac organ), and are capable of 
rapid movement involving the whole muscular organ; while the 
unstriated muscular tissues perform functions pertaining to organic 
(vegetative) life, are involuntary in their action, contract slowly, 
and principally affect the tissues in their own extent only. 
In the embryo, up to the third month, this difference of the fibres 
in the muscular tissue is not apparent, though it must exist in a 
rudimentary way; for, under normal conditions, tissues do not 
change in organic structure. It is questionable if the change of car- 
tilage into bone can be regarded as a fundamental one. There is an 
increase in the quantity of tissue merely — the parts increasing in 
size and weight, though the increase does not involve a change in 
elementary composition. During development, the number of ele- 
mentary fibres is not increased from that which existed in the muscle 
tissue of the foetus. Muscle tissue forms about 45 per cent of the 
entire mass of the adult body. 
The Striated Muscle consists of the following structures:— 
1. The Perimysium Externum, a connective-tissue envelope 
(fascia, aponeurosis) surrounding the muscle (1, Fig. 70). It sends 
partitions (septa) inward, supporting the nerves, lymphatics and 
blood-vessels, and then forming the perimysium internum. 2. The 
Perimysium Internum (2), a delicate connective-tissue envel- 
ope derived from the perimysium externum. It separates the mus- 
cular fasciculi, or bundles of muscular fibres (3), and sends parti- 
tions inward, which constitute the endomysium (4). 242 
THE MUSCULAR TISSUES. 
The Fasciculi (3) of a small muscle are as long as the muscle 
itself, while those of long, large muscles are from one to two inches 
in length. 3. The Endomysium (4) consists of delicate con- 
nective-tissue, derived from the perimysium internum, and forms par- 
Fig. 70. 
Diagram of transverse section of a striated muscle. 
1, Perimysium externum. 2, Perimysium internum. 3, Fascicu- 
lus. 4, Endomysium. 5, Sarcolemma, surrounding the muscular 
fibres. 6, Muscular fibre. 7, Muscular fibre-cell. 8, Blood-vessels. 
9, Nerve. 10, Lymphatic vessel. 
titions or septa extending inward and forms the sarcolemmae. The 
endomysium and sarcolemmae separate the muscular fibres, they car- 
ry and support the capillary ves-els and nerve-fibres within the fas- 
ciculi of voluntary or striated muscles. These muscles are compos- 
ed of a great number of fasciculi, each consisting ot many muscular 
fibres running in parallel lines, and held together in bundles (fasci- 
culi ) by the perimysium internum. The fibres of a fasciculus are 
not all of equal length. Their ends are generally attached to adja- 
cent fibres by the ensheathing sarcolemma (5), a strong, adhe- 
sive substance, which continues from each fibre as a tendinous 
fibrilla to the termination of the fasciculus, and thence to the end 
of the muscle, where the sarcolemmae and endomysium blend to- 
gether and merge with the perimysium externum, forming the 
tendon, which is attached to the periosteum of a bone. It is 
noticed that the larger nerves and vessels of a muscle are situated 
between the perimysium externum and perimysium internum 
(8, Fig. 70), while the nerve - fibrillae (9) and capillary-vessel THE MUSCULAR TISSUES. 
networks (10) run in the endomysium; i. e., externally to the sar- 
colemma and muscular fibres, but within the perimysium internum.. 
The motor nerve-fibres enter the muscular fibres (Fig. 37), but the 
capillary vessels do not. 4. The Sarcolemma (5) is a delicate, 
structureless, transparent, and elastic envelope, surrounding the mus- 
cular fibre, and holding it in proper shape. It sends transverse- 
partitions (the membranes of Krause) across the muscular fibre 
(2, at C, Fig. 71) at regular intervals, separating each space (1), 
which contains a nucleated cell (5). These cells not only maintain 
Fig. 71. 
Diagram of muscular fibres 
A, Four partly isolated striped fibres. P>,'Three isolated unstriped 
fibres, each having a nucleated cell. C, One striped fibre elongated 
(in a state of repose), and its nucleated cells. D, The same striped 
fibre (C) contracted—shortened and thickened—as during activity. 
1, Disk, or division, of a striped fibre as it appears under polarized 
light. 2, A faint layer (Krause’s membrane), constituting the septum, 
or stria, between the disks. 3, A single refractive substance (Hensen’s 
disk). 4, Double refractive substance. 5, Nucleus within the cell. 
the function of nutrition and reparation of the muscular fibre, hut 
also during activity secrete from the blood (in a way similar to that 
of glandular cells) the contractile substance (myosin) for the strise 
and sarcolemma. The contractile substance is dispersed more or 
less throughout the muscular fibre, but the greater quantity is held 
in the sarcolemma and membranes of Krause (strioe). Myosin is a 
nitrogenized substance forming the chief constituent of muscles. 244 
THE MUSCULAR TISSUES. 
The Muscular Fibre consists of a long, thin cylindrical mass, 
covered by a sheath termed sarcolevima. It contains, besides nu- 
cleated cells (C, D, Fig. 71), a sarcous substance. These fibres vary 
in size with the age of the person, averaging in the adult from 
l-500th to l-250th of an inch in diameter, and from one-fourth to 
one-half of an inch in length. In very short muscles, such as the 
stapedius in the middle ear, the fibres are as long as the muscle. 
The average distance between Krause’s membranes (striae) is 
l-9400th of an inch, the extremes being l-15000th to l-6000th, ac- 
cording to the extent of the contraction or relaxation of the fibre. 
Physiologically, the properties of muscles are fourfold: (1) Irri- 
tability; (2) Elasticity; (3) Tonicity; (4) Contractility. 
Irritability of a muscle is that inherent property by which its 
cells are brought into action through an impulse received from a 
nerve, from the blood, from a stimulus applied directly to them, from 
excrementitious matter retained in its tissue, or from temperature. 
Every muscular fibre is supplied by a branch of a motor nerve-fibre, 
■ending in the terminal plate (Fig. 37) so-called; that is to say, one 
original nerve-fibre may, through its many ramifications (2, Fig. 33), 
supply many muscular fibres. The nerve-fibre enters the muscle 
generally at a point near its middle, at a place the least affected 
by its contraction. Of all the tissues of the body, the superficial mus- 
cles and the skin are most abundantly supplied with nerves. They 
run along the outside of the sarcolemma of each muscular fibre, 
similar to the blood-vessels; but a motor nerve-fibre ultimately 
penetrates the sarcolemma, its axis-cylinder leaving the nerve 
fibre-sheath and the white substance of Schwann, and terminating in 
the muscular fibre in a special expansion called the terminal plate 
(Fig. 37), or motorial end plate. The sensory nerve-fibres terminate, 
not in the muscular fibres, but between them, in the endomysium 
and sarcolemma. It is a peculiar fact that the power of an im- 
pulse conveyed through a motor nerve-fibre, producing contraction 
of a muscle, is largely determined by the length of the nerve-fibre. 
It seems to be a general law of animal life that the strength of an 
impulse through a motor nerve-fibre increases correspondingly with 
the length of the fibre. Hence, nervous actions on the muscles of 
the hands and feet are more powerful than on muscles (compara- 
tive size considered) nearer nervous centres. A further peculiarity 
of striated muscles is, that the more frequently they are called 
into action, if that action be not too prolonged, the larger and more 
vigorous they become, as is evinced in all forms of judicious exer- THE MUSCULAR TISSUES. 
245 
cise. This follows from the increased demand for oxygenated blood 
and appropriate nourishment. The number and size of tendinous 
fibres in connection with the muscular fibres also play an important 
part in the power of muscular action. An abnormal temperature 
of the body affects the property of irritability; it is either much 
increased or much lowered. Any interference with the reflexes to 
muscles, or with their nutrition, enfeebles or wholly destroys the:r 
irritability. Nothing so effectually impairs their nutrition as disuse, 
and nothing so completely destroys it as the division of the nerve 
(destroying transmission of reflexes)—involving also the loss of con- 
tractile power. If called into action, however, by massage, or other 
stimulating treatment during the period of the muscle’s impairment, 
and regular nutrition be continued, its irritability is retained. 
Muscular tissue is excitable independently of nervous influence; 
there may, therefore, be loss of muscular excitability without 
loss of nervous excitability, and vice versa. Curare paralyzes the 
motor nerve endings without affecting the contractile power of the 
muscle. In curare poisoning, reflex impulses through the motor 
nerve-fibres have no effect on the muscle; still the muscle retains its 
excitability to stimulation applied directly to the muscle. Landois 
states “that ammonia, carbolic acid, or lime water applied to 
muscles produces movement, but not when applied to the nerves.” 
Elasticity of a muscle is that inherent property by which its 
fibres and tissues are enabled to stretch and elongate, or shorten, to a 
certain extent, without injury. It moderates the effects of powerful, 
sudden stimulation, acting gradually, and preventing detachment at 
the points of origin and insertion. This is an important endowment, 
well illustrated in the extension and flexion of limbs. Normally, all 
fibres do not act simultaneously; for when some cease to contract, 
their extremities are acted on by the contractions of adjacent fibres. 
Tonicity of a musole is that inherent quality of sensitiveness 
by which its fibres and tissues become aroused to functional activ- 
ity in response to either direct or indirect stimulation. In health 
the tonicity of groups of muscles is so adjusted as to constitute a 
mutual counterbalance. This counterbalance may be destroyed, 
however, by paralysis or impaired nutrition. The tonicity of one 
set of muscles is then weakened; as in lead-palsy, for instance, in 
which the extensors of the forearm and hand lose their natural 
strength, so that the contraction of the flexors keeps the fingers con- 
stantly bent upon the palm. In health the tonicity of the flexors 
usually exceeds that of the extensors— in profound sleep, for 246 
THE MUSCULAR TISSUES. 
example, when the influence of the will and the nervous system 
is lulled, the hands being partially closed. 
Contractility of a muscle is that inherent, characteristic prop- 
erty by which its fibres and tissues forcibly contract and shorten 
in a particular direction in response to the will, external irritation, 
or stimulation; exhibiting itself in dual form, contraction and relax- 
ation. It is most impressively shown in the voluntary muscles and 
heart, which, when in action, exhibit powerful contractions, alterna- 
ting with relaxations. Striped fibres, as previously pointed out, form 
the greater mass of the quick-acting muscles, which are generally 
attached to bones by tendons. They are commonly controlled by 
the will, and are, therefore, called voluntary muscles; though not 
altogether correctly so, as many of them—e. g., the heart; and along 
the spine, neck, and middle ear — are beyond the will’s control. 
The sphincter muscles and diaphragm are composed of striped 
fibres. The enclosing structure of cavities is supplied with longi- 
tudinal, circular, and oblique muscular fibres, which act simulta- 
neously in contraction; e. g., those of the heart, blood-vessels, 
lymphatics, stomach, gall-bladder, intestines, uterus, Fallopian 
tubes, urinary bladder and ureters. In all cases where muscular con- 
traction takes place, some other tissue is moved, or tends to move. 
The contractile movement of the striped fibre is wonderfully 
rapid, occurring at the instant of stimulation. The motor nerves 
of the muscular system are derived from the cerebrospinal system. 
The power of contractility is made possible, principally, by the pres- 
ence of the nitrogenized compound myosin, a semifluid substance 
contained in the striae of the muscular fibres and in the sarcolemma 
surrounding these fibres. Muscular contractions occur alternately 
in the fasciculi, passing along the fibres within the fasciculi from 
the point of stimulation, in a wave traveling from 6 to 16 feet 
per second. The velocity corresponds to the state of vital activity, 
and of temperature. When vital activity is very low, stimulation 
causes -only a local contraction and slight elevation at the point of 
contact. Stimulation to muscular contraction takes place in one 
of two ways: (1) By the application of the stimulus to motor nerves, 
termed indirect stimulation; (2) to the muscular tissue itself, term- 
ed direct stimulation. When muscles are active, the ve-sels dilate, 
more blood and nutrition are supplied, and more carbonic acid ele- 
ments are formed and gas given off at the organs of exit. If excess- 
ively stimulated for a time the cells of muscles become exhausted 
(as in glandular secreting cells); loss, therefore, of contractile THE MUSCULAR TISSUES. 
247 
substance follows. Muscles are extremely vascular. The capillary 
arteries, veins, and lymphatics run within the endomysium (4, 
Fig. 70). They are distributed in the endomysium (outside of the 
sarcolemma), in lines nearly parallel with the muscular fibres, but 
do not enter the fibres. The nutriment (pabulum) required for the 
maintenance and growth of these fibres is drawn by absorption 
through endosmotic imbibition from the network of capillary ves- 
sels, through the sarcolemma. The excrementitious substances are 
drawn by the absorbent vessels through exosmotic absorption from 
the muscular fibres, too, through the sarcolemma. The power of 
imbibition of nutrient matter and absorption of excretory matter 
is increased during contractile activity. The supply of blood is not 
only required for the nutrition of the muscular tissue, but also 
affords the oxygenous condition requisite for its action. That blood 
may exercise its salutary influence it must be arterialized. The 
muscles soon lose their contractile power if the arterial blood supply 
has been suspended, either by cessation of circulation or want of 
proper aeration. 
The activity of the muscular structure (striped fibres) of the heart, 
being necessarily constant, reparation must take place pari passu 
with its waste; during health no sense of fatigue is experienced in 
the heart. In other striated muscles, under the control of the will, 
reparation is not so rapid, and their prolonged exertion induces 
impairment and fatigue, attributable to defective nutrition. In 
this case prolonged rest is rendered essential to recovery. Sodium 
chloride and the potassium salts are especially necessary for the 
normal nutrition of muscles. If these salts are withheld for some 
time, the muscles atrophy, and the central nervous system and the 
digestive apparatus become disturbed. Of all saline solutions, 
chloride of sodium is the most necessary; again, of all the salts, it 
injures the nervous and muscle tissues the least. 
The muscular tissue, i. e., its contractile substance, tires out sooner 
than its nerve terminals. In paralysis of the muscle, its nutrition 
becomes defective and the myosin measurably disappears; the 
muscle loses its contractile power correspondingly. By massage the 
flow of blood and lymph is facilitated, nutrition favored, and waste 
products in fatigued and weakened muscles are removed. During 
muscular fatigue, an increase of decomposition of matter in the 
muscle takes place. By local absorption of nutrition, or by pass- 
ing through the blood of the muscle a weak solution (6 to 8 per 
cent) of chloride or carbonate of sodium, or a constant electrical 248 
THE MUSCULAR TISSUES. 
current, the muscle soon recovers its loss. Generally, under artifici- 
al stimulus, muscular contractility continues after death for a time, 
if the muscle be kept cool and moist; but is lost as soon as the 
myosin coagulates or degenerates. Striped muscular fibres retain 
their contractility much longer than unstriped, the latter losing it 
almost immediately after death. 
Muscular Action is referable to muscular contraction, involv- 
ing a shortening and hardening of the fibres; and the bringing of 
their ends nearer together (D, Fig.71). The fibres, including the 
sarcolernma, possess the property of contraction—not the fat, neither 
the connective tissue, nor endomysium of the muscle. In regard to 
simplicity of mechanism and amount of work performed, muscles 
are vastly more perfect than any human device; the more they are 
normally exercised the stronger they become and the more work 
they can accomplish. The more fibres contained and distributed 
transversely in a muscle the stronger it is. In its formation some fat 
or adipose tissue is interspersed more or less within the fibres, be- 
tween the fasciculi and fibres, and between the fasciculi themselves. 
Muscle-tissue when at repose is neutral or slightly alkaline. The 
contractile activity moves the muscle and the part to which it is 
attached. This causes partial degeneration, and at the same time 
involves the mortality of certain constituents of the muscular fibres 
and connective tissue; then acid and excrementitious substances 
form more quickly in the muscle. Vital tissue acid (a form of lactic 
acid) is the only acid formed directly, and is the result of what is 
known as the katabolism of muscular tissue. The acidity is neutral- 
ized by the alkalinity of the blood, resulting in carbonic acid 
elements, which are carried away from the muscular tissues by the 
efferent vessels to the organs of exit. The quantity of carbonic acid 
elements evolved is far greater during physical activity than during 
the process of muscular nutrition simply. It is removed from the 
tissues principally by the capillary veins, while other excrementi- 
tious substances are removed by the lymphatics. How this activity 
is effected, may be understood when we consider that protoplasm is 
a substance subject to incessant molecular changes. The changes 
in the vital economy termed metabolism—going on under the in- 
fluence of the activity of the vital principle, guiding the chem- 
ical combinations within the vital animal economy — are properly 
divided into two kinds: One, termed anabolism, implies an upward 
series of chemical combinations, by which the latent energies of inert 
food are transformed into the living energy of the protoplasm of THE MUSCULAR TISSUES. 
249 
the bodily tissues. The other, termed Jcatabolism, involves a down- 
ward series of changes in the vital economy, by w’hich the living 
tissues are partly broken up and the waste matter is set free. As 
protoplasm itself undergoes changes according to the pabulum sup- 
plied, so it modifies the tissues accordingly. The form and function 
of protoplasm, therefore, are the effects of certain causes. Again, 
living matter (protoplasm) acts upon, and is powerfully acted upon 
by, the matter surrounding it. The food entering the body holds 
energy in latent form (chemically speaking), and supplies the 
material for physical action. By manifold transformations and 
chemical changes, the food materials are changed into true tissue 
pabulum, rirst exhibiting energy as heat only. It finally becomes 
a part of the living cell-substance—i. e., protoplasm—and is then 
enabled to give forth energy that may be utilized in nervous and 
muscular action. It is through the process of nutrition that the 
various parts maintain the same general conditions of form, size, 
and composition that they attained by growth and development. 
In health an adult maintains for a number of years nearly the 
same features, weight, and size, although simultaneously the tissues 
continually undergo decay and renovation. Prolonged mental exer- 
tion is often followed by an increased amount of alkaline phos- 
phates, found in the urine, arising from the increased destruction 
of the cell-tissues of the brain; yet the brain substance does not 
diminish, owing to the active reparative processes at work. The 
same is true of the muscular cell-tissue; an increased amount of 
exercise is directly followed by an increased excretion of the ordi- 
nary products of the decomposition of cells and of nitrogenous 
tissues, assimilation of pabulum at the same time restoring the 
wasted tissue. 
Muscular activity increases heat, extended muscular contractions 
evolving more heat than limited ones. When we ascend a flight 
of stairs two steps at a time more heat and fatigue ensue than when 
we ascend the same flight leisurely, one step at a time. The trans- 
formation of phjrsical energy within the body takes place chiefly 
in the muscular tissues and in the secreting glands. 
The Unstriped or Involuntary Muscular Fibres con- 
sist of a series of longitudinal or cylindriform filaments, somewhat 
granular, pale, and flattened, from about 1-300th to 1-100th of an 
inch long, and from about l-3000th to l-1500th of an inch in thick- 
ness, and pointed at their extremities (B, Fig. 71). These fibres 
are usually marked at intervals by one or two minute elongated 250 
THE MUSCULAR TISSUES. 
cells containing nuclei with nucleoli. The cells are from about 
l-500th to l-200th of an inch long, and from l-5000th to l-2500th 
of an inch broad. Nerve-fibriilae are in connection with these cells, 
and run longitudinally with the unstriped fibres. The impulse 
through the nerve-fibre to the cell induces the contraction of the 
sarcolemma. As the unstriped muscular fibres are differently con- 
structed from the striped, their stimulation, contraction and time of 
action differ from them also. During contraction the muscular 
fibres become shorter and thicker. The tonicity of unstriped fibres 
exerts a slow, prolonged contractile movement; more so than that 
of striped fibres. Generally, unstriped fibres, unlike the striped, 
have no fixed points of attachment; but form continuous invest- 
ments around cavities wdthin the body, as in the intestinal canal, 
bladder, uterus, and blood-vessels; or are dispersed through the 
substance of tissues, as in the cutis of the skin, to which they impart 
a contractile property. In the walls of capillary vessels these 
muscular fibres lie in single layers, and are, as it were, consoli- 
dated; the end of one being joined to the body of the other. In 
other situations, as in the walls of the intestines, stomach, or blad- 
der, they exist in double and triple longitudinal, oblique, and 
transverse layers. Unstriped fibres contract very slowly, requiring 
a longer time than the striped for the nerve influence to take 
so that an interval exists between the instant of stimulation and 
that of contraction. Such muscular fibres are generally found in 
internal organs, where gradual and lasting contractions are requir- 
ed. Their nerve supply emanates generally from the sympathetic 
system, and they are, therefore, uncontrolled by the will. Those 
of the alimentary canal are prompted to action more readily by 
direct alimental stimulus than in any other way. Weak solutions 
of mineral salts, bile, glycerine, and salts of iron, also stimulate 
them. The striped fibres of muscles, on the other hand, are more 
readily called into action by stimulus through the nerves of the 
cerebro-spinal system. CHAPTER XXVI. 
REPRODUCTION. 
Reproduction of animal life is accomplished by one of three 
processes—fission, gemmation, or fecundation. 
Fission (dividing or splitting) is the reproduction of an organ- 
ism by its division into two parts, each part possessing potentially 
all the functional powers of the parent. 
Gemmation, or budding, is where an organism originates by a 
bud arising from some part of the parent structure, the pedicle or 
stem of the bud gradually disappearing, when, being liberated, the 
new organism assumes a perfected form, closely resembling that 
of the parent. 
Fecundation is reproduction resulting from the impregnation 
of an egg (ovum), requiring in its accomplishment two individ- 
uals of the same species but of opposite sex—the male furnishing 
the sperm-cell (spermatozoon), and the female the ovum, contain- 
ing the germ-cell. 
Propagation by fission and gemmation occurs in well-marked 
forms among the lower orders of animal life only. Amoeba and 
some varieties of infusoria present good illustrations of reproduc- 
tion by division (or fission); other varieties of infusoria, and polyps, 
are examples of reproduction by gemmation. 
Reproduction distinguishes in a striking manner organized liv- 
ing beings from unorganized, inert bodies. Reproductive cells go 
through a series of developmental changes, which do not interfere 
materially with the general life of the parent organism. If the 
fertilized ovum of any species be deposited where the special con- 
ditions favoring its development are present it acquires maturity; 
otherwise not. 
The Uterus, or womb, of the human female is a pear-shaped 
organ (Fig. 72; and a. Fig. 73), situated in the pelvis between the 
bladder, and the rectum. It is divided into three parts, a fundus, 
body, and neck (cervix); the neck being about half as long as the 
body, but narrower. The uterus is composed principally of three 
kinds of tissue layers; externally, of a serous (5, Fig. 72); inter- 252 
REPRODUCTION. 
nally, of a mucous (7); and intermediately, of a thick fibro- 
muscular coat (6 and 9). 
Up to about the fourteenth year, or time of puberty, the uterus 
is small. At this time, however, it increases in weight to about an 
ounce and a-half, and in length to about two and a half inches. 
Its internal cavity is constricted 
just below the midd e, forming the 
os internum (3), this marking the di- 
viding line between the cervix and 
the body. The orifice (4) at the lower 
part of the cervix is termed the 
os externum, or mouth of the womb. 
The cervix projects partly into the 
vagina (10). The dome (8), or up- 
per part of the uterus, is called the 
fundus. At its junction with the body 
the Fallopian tubes (11,11) enter. The 
ovarian and round ligaments (p, h, 
Fig. 73) lie imbedded in the broad 
ligament (e), which is a sero-mem- 
branous structure on each side, serv- 
ing to hold the uterus in position. 
The muscular wall of the uterus is 
about half an inch in thickness, the 
walls being separated internally 
from side to side by a triangular 
cavity (1, Fig. 72). In antero- 
posterior section, however, this cav- 
ity appears as a narrow slit lined 
with mucous membrane (7), which 
constitutes nearly one-fourth of the 
entire thickness of the uterine wall 
and is firmly adherent to its mus- 
cular structure (6). Whenever the 
uterus contracts normally its mucous membrane is thrown into 
numerous folds. The membrane is pale-red in color, and still paler, 
and much thinner, in the cervix. At the os externum the mem- 
brane is very thin, especially in the virgin. Its surface is lined 
with columnar epithelial cells, which during pregnancy become 
changed to the pavement variety. It also contains numerous ori- 
fices of the so-called glandular follicles of Naboth , the length of 
Fig. 72. 
Diagram of the uterus. 
1, Cavity of the uterus. 2, Cav- 
ity of the neck (cervix) of the uter- 
us. 3, Os internum. 4, Os exter- 
num, or mouth of the womb. 5, 5, 
Serous layer. 6, 6, 6, Fibro-mus- 
cular layer. 7, 7, 7, Mucous layer. 
8, Fundus of the uterus. 9, 9, Neck 
of the uterus. 10, Vagina. 11,11, 
Fallopian tubes. 12, Bristle run 
through the channel of one Fallo- 
pian tube. 13, Fertilized ovum. 
14, Membrana decidua. REPRODUCTION. 
253 
which is proportionate to the thickness of the membrane. Their 
walls are lined with ovoid epithelial cells. The follicles furnish 
an increased secretory surface, and their function is to secrete an 
alkaline substance. They sometimes close up and become swollen 
with their secretion, and the swelling may be mistaken for ova or a 
foetus. Such enlarged follicles are termed ovula of Naboth, or hydatids. 
They appear as yellowish vesicles of various sizes, especially in the 
mucous coat of the cervix uteri (2, Fig.72) where the glandidx folliculi 
Nabothi, about 10,000 in number, lubricate the parts, during deliv- 
Fig. 73. 
Diagram of the uterus and its appendages. 
a, Uterus, b, Os uteri, c, Neck of the uterus, d, Fundus of the 
uterus, e, e, Broad ligament, f, Ovary within the broad ligament, 
g, Indicating the margin where one-half of the broad ligament is cut 
off. h, li, Round ligaments, i, Ovary, the broad ligament being re- 
moved. j, j, Fallopian tubes, or oviducts, k, k, Fimbriated extrem- 
ities of the Fallopian tubes. 1, Vagina, m, Fringe-tube connecting 
the ovary with the Fallopian tube, or oviduct, p, Ovarian ligament. 
ery, with an alkaline secretion. In morbid conditions, this secre- 
tion is often increased and of acid reaction. The entire uterus is 
well supplied with lymphatic and capillary blood vessels, very dis- 
tinct around the follicular orifices, especially when the uterus is 
excited to functional activity, as during the menstrual period. 
The Fallopian Tube, or Oviduct (one on each side of the 
uterus, 11, Fig. 72; and j, Fig. 73), through which the ovum passes 
from the ovary (i) to the uterus, is situated at the upper part of the 
broad ligament. Its canal at the uterine end is so small as to 
barely admit the passing of a bristle through it (12, Fig. 72). It 
enlarges towards its outer extremity, which is trumpet-shaped, and 254 
REPRODUCTION. 
from its fringed appearance is termed the fimbriated extremity (k, Fig. 
73). Wilson says: “ The remarkable manner in which this circu- 
lar fimbriated extremity applies itself to the surface of the ovary 
during sexual excitiment, has gained for it the additional title of 
morsus diabolic Each Fallopian tube is about four inches long, 
and is lined internally with mucous membrane and ciliated epithe- 
lial cells, the direction of the vibrations pf the ciliie being towards 
the cavity of the uterus. One of its fringed processes (m) forms a 
connecting passage-way leading from the outer end of the ovary 
(i) to the Fallopian tube. A short ligamentous cord proceeds 
from the fimbriated extremity, attached to the distal end of the 
ovary, and serves to guide the tube in its seizure of Jiat organ. 
The Round Ligament (h) (one on each side of the uterus), 
formed of fibrous and unstriped muscular tissues, extends from the 
side of the fundus of the uterus through the broad ligament, to the 
labia majora, and corresponds to the spermatic cord in the male. 
In the foetus and young female the canal through which the round 
ligament passes is called the canal of Nuck. In the adult this 
canal is gmerally obliterated, though it sometimes remains open, 
affording a chance for the abnormal descent of an ovum, or it may 
become the seat of a hernia. 
The great serous membrane investing the abdominal viscera 
passes over the upper part of the bladder and downward between 
it and the uterus, to a point midway between the os externum and 
the os internum, thence upward (5, Fig. 72) over the fundus of the 
uterus, then downward (5) behind the vaginal fornix where its dip 
forms the pouch of Douglas. Thus the peritoneum forms a cap, as 
it were, embracing the whole of the superior portion of the uterus 
antero-posteriorly. From the sides of the uterus to the inguinal 
region the peritoneum lies doubled, forming the broad ligaments. 
The Broad Ligament (e, e, Fig. 73), as previously stated, con- 
sists of two layers of the peritoneum, which encloses the Fallopian 
tube, ovary, and ovarian and round ligaments, besides holding in 
its meshes numerous muscular fibres. These fibres, by their con- 
traction, exercise an important physiological function in bringing 
all the structures into harmonious action. The broad ligaments 
hold the uterus in position in the center of the pelvic cavity, and 
admit of considerable antero-posterior movement of the uterus, to 
accommodate the distension of the bladder and the rectum. 
Blood Supply.—The two uterine arteries are derived from the 
internal iliacs, and pass to the sides of the neck of the uterus. REPRODUCTION. 
255 
They are very tortuous in their course, admitting of great uterine 
distension during pregnancy without diminution of calibre. They 
supply blood to the uterus and give off branches that pass between 
the layers of the broad ligament to the bladder. The two ovarian 
(spermatic) arteries arise from the front of the descending aorta 
just below the renal arteries. They, too, pass between the folds of 
the broad ligament, supplying the ovaries and Fallopian tubes, and 
a small branch anastomoses with the uterine artery. The veins 
accompany the arteries. 
Nerves.—The uterine nerves are derived from the inferior hy- 
pogastric plexus situated at the side of the rectum, vagina, and 
bladder. The plexus are partly formed by fibres from the second, 
third, and fourth sacral nerves. The nerves accompany the uterine 
arteries, supplying the uterus and Fallopian tubes. The ovarian 
nerves emanate from the spermatic plexus, and supply the ovaries 
and the broad and round ligaments. 
The Lymphatics are large and numerous, especially in the im- 
pregnated uterus, and communicate with the pelvic and lumbar 
lymphatic glands. Thrombosis of these vessels, especially during 
child-birth, interferes with the removal of decomposed matter, giv- 
ing rise thereby to puerperal fever. 
The Ovary (i, Fig. 73) in the female is analogous to the testicle 
in the male. The former produces the germ-cell; the latter, the 
sperm-cell, or spermatozoon, for future offspring. The ovary (one 
on each side of the uterus) is imbedded in the broad ligament pos- 
teriorly, and has a special white fibrous tissue covering, termed tu- 
nica albuginea ovarii (1, Fig. 74). The inner extremity of the 
ovary is connected with the uterus by the ovarian ligament (p, Fig. 
73); its outer, with the fimbriated process (to) of the Fallopian 
tube. In appearance the ovary is white, smooth, and plump, about 
one and a-half inches long, three-fourths of an inch wide, and half 
an inch thick. Its weight is from one to two drachms. It consists 
of unstriped muscular fibres, interlaced with connective tissue, 
blood-vessels (8, Fig. 74), lymphatics, nerves (9), and, scattered 
throughout its mass, from 15,000 to 25,000 small, round, transpar- 
ent sacs of various sizes and stages of development termed Graaf- 
ian vesicles, to which some apply the term ovisacs, imbedded in the 
ovarian stroma and containing a clear, colorless, albuminous fluid. 
Each vesicle also contains an ovum, or vesicle of Baer (6, 6). The 
membrana granulosa lies between the Graafian vesicle (2) and the 
zona pellucida (3), and consists of nucleated cells. Each Graafian 256 
REPRODUCTION 
vesicle has a minute follicular duct terminating at the surface 
of the ovary. The majority of ova in the ovary remain so mi- 
nutely small (7, Fig. 74) that a 
female of eighteen may have 
from 30,000 to 50,000 in both 
ovaries. Before puberty a large 
ovum is about l-500th of an 
inch in diameter, and is to all 
appearances a cell; its zona 
pellucida, or vitelline mem- 
brane (3), being its wall; the 
vitellus (5), its cell contents; 
the germinal vesicle (4), its 
nucleus; and the germinal spot, 
its nucleolus. The diameter of 
a mature ovum (2 to 5), is 
about l-120th of an inch; its 
germinal vesicle (egg-cell, nu- 
cleus, or vesicle of Purkinje), 
about l-720th of an inch, sur- 
rounded by a delicate mem- 
brane; and the germinal spot, 
which is about l-4000th of an 
inch. 
Fig. 74. 
Diagram of an ovary. 
1, Tunica albuginea ovarii. 2, Graaf- 
ian vesicle, or ovisac, surrounding the 
ovum. 3, Zona pellucida, or vitelline 
membrane. 4, Germinal vesicle con- 
taining the germinal spot. 5, Yelk of 
the ovum, b, 6, Ova gradually enlarg- 
ing to maturity similar to the one al- 
ready mature (3). 7, Minute ova (unde- 
veloped). 8, Blood-vessels. 9, Nerves. 
10, Corpus luteum, or ruptured spot 
■of a Graafian vesicle, after liberating 
the ovum. 11, Cells lining the inter- 
nal surface of the tunica albuginea 
ovarii from which the ova originate. 
Ovulation.—From an early period in foetal life, when the ova 
form in the ovary, they grow by increase of the yelk surrounding 
the germinal vesicle (4). Each ovum is finally inclosed by a mem- 
brane termed the zona pellucida (3), situated within a small sac 
termed Graafian vesicle (2). The maturation and discharge of 
an ovum takes place in the human female, generally every twenty 
eight days, and is normally associated with menstruation, and 
•constitutes the phenomenon of ovulation. Not only the Graafian 
vesicle, but all parts of the internal generative system partici- 
pate in this periodical manifestation. The enlargement of the 
Graafian vesicle, with its contained fluid and ovum, is due to 
increased blood vascularity, which goes on until the vesicle rup- 
tures. This generally taking place at the menstrual periods, 
though during sexual excitement the morsus diaboli may prema- 
turely induce a rupture and liberate an ovum from the ovary. 
At the time the ovum escapes from the ripe Graafian vesicle the 
germinal vesicle and germinal spot move towards the periphery of REPRODUCTION. 
257 
the yelk nearest the point of rupture, the germinal spot placing 
itself in a position favorable to a visit from the spermatozoon. The 
bursting of the Graafian vesicle takes place at the tunica albu,- 
ginea (1, Fig. 74), so that the ovum is received by the oviduct (m, 
Fig. 73), and passes through the Fallopian tube into the uterus. 
Previous to the time of rupture, the internal layer (3, Fig. 74) of 
the Graafian vesicle becomes yellow and waxy by the aggrega- 
tion of minute oil-globules on its surface. After the rupture the 
yellow appearance becomes more distinct by direct exposure of the 
layer (3); hence the name corpus luteuvn (10) applied to the 
laceration or scar resulting. This name applies generally to all cor- 
pora lutea, whether impregnation has taken place or not. The fol- 
lowing distinction, however, is observed; When impregnation of 
the ovum does not take place the congestion of the uterus, ovaries, 
and neighboring parts disappears, the place of rupture of the 
Graafian vesicle shrivels, contracts, heals rapidly (within two or 
three weeks), becomes absorbed, and the spot of rupture and its 
yellowness is scarcely discernible; it is then termed false corpus lu- 
teum. If, however, pregnancy occurs, then the functional activity 
of the uterus excites an increased afflux of blood to the ovaries 
and neighboring parts as well as to itself; hence, they remain more 
or less congested. The healing of the rupture is thus prevented, 
the edges of the laceration degenerate, and the ruptured spot be- 
comes larger, and is supposed not to heal until after delivery. Such 
a, scar on the ovary is termed the true corpus luteum (10, Fig. 74). It 
is believed to be the subsequent course which determines the corpus 
luteum of pregnancy—it is more fully developed and of longer 
duration, harder, larger, and at a later stage has a distinct white 
covering with a large stellated cicatrix. Congestion of the ovary 
and neighboring parts may continue, however, for some time after 
a catamenial ovulation, without impregnation, the healing being 
prevented and the scar remaining large. Hence, the existence of 
a large corpus luteum on the ovary affords no evidence whatever 
of intercourse having taken place. On the other hand, its absence 
would not warrant the belief that conception had never taken 
place. The terms true and false corpora lutea are, therefore, not 
strictly definite, and may lead to serious mistakes in a medico- 
legal sense. The discovery of a fertilized ovum (embryo), and 
its development in the female generative organ, is perhaps the only 
positive proof of conception. (Vide Moles and Hydatids.) 258 
REPRODUCTION. 
The Testicle (T, Fig. 75) is a glandular structure, consisting of 
about 400 lobules—lobuli testis (C). These lobules are composed 
of minute convoluted tubes, lined with cells termed vesicles of 
evolution, forming groups of four to 
six; and from the nuclei of these 
vesicles, or cells, the spermatozoa 
are developed, constituting the ac- 
tive generative element of semen. 
The tunica albuginea testis (A) 
sends out fibrous septa between the 
lobuli testis, thereby separate them. 
Spermatozoa (S, Fig. 75).—At 
and after the age of puberty the 
testes of the male secrete a fluid 
termed semen, which is a glutinous, 
whitish substance, with a peculiar 
odor, containing minute elongated 
bodies, the spermatozoa (S), which 
are thread-like bodies, each about 
50 micromillimetres long, with a 
pear-shaped head (1), rod-like mid- 
dle part (2), and ciliated caudal 
prolongation (3). During sexual 
excitement some of the cells within 
the lobuli testis (C) burst, setting 
the spermatozoa free into the se- 
minal fluid secreted by the organs 
F, G, H, I, Fig. 75, and discharged 
by the vas deferens (J) through 
the male organ of coition into the 
vagina of the female. The sper- 
matozoa are capable of move- 
ments upward in the vagina and 
uterus — no doubt due not only to their own propelling power, 
but also favored by the peristaltic action of muscular fibres in the 
mucous membrane of the vagina, uterus, and Fallopian tubes. 
The extent of their movement is from 0.05 to 0.5 of a micromillimetre 
per second during several days. When spermatozoa are absent 
from seminal fluid, as in debility, or old age, impregnation is 
impossible. It is their absence from the semen that causes hybrids 
to be sterile. 
Fig. 75. 
Diagram of the testicle and 
its ducts (T),and two 
spermatozoa (S). 
A, A, Tunica albuginea testis. 
B, Mediastinum testis. C, Lobuli 
testis. D, D, Vasa recta. F, Vasa 
efferentia. G, Coni vasculosi, con- 
stituting the globus major epidid- 
ymis. H, Body of the epididymis. 
I, Globus minor epididymis. J, 
Vas deferens. K, Vas aberrans. 
P, Rete testis, forming a layer in- 
terspersed with capillaries of the 
spermatic artery between B and 
the internal portion of the tunica 
albuginea. REPRODUCTION. 
259 
Fecundation is the fertilization of the ovum by the sperma- 
tozoa of the semen. Up to the third month of gestation the ovum 
is termed the embryo, after that the foetus. At the time of sexual 
excitement the erectile tissue of the male organ is acted upon reflexly 
through the nervous centre situated in the lower portion of the 
spinal cord, culminating in orgasm and erection of the muscular 
fibres of the male sexual organ, through which the semen is directly 
ejaculated by the contraction of the fibres of the vas deferens (J, 
Fig. 75). The contraction of the fibro-muscular tissue surrounding 
the prostate gland and the urethra at the neck of the bladder pre- 
vents regurgitation towards the 
bladder. Thus, during the act of 
coition, the semen passes into the 
vagina at or near the os uteri 
externum. The discharge of se- 
men into or near the os is not 
absolutely necessary to impreg- 
nation, however, as there are 
cases on record where the sem- 
inal fluid came in contact with 
the pudendum simply, the hy- 
men being intact; yet the sperm- 
atozoa made their way inward 
to the ovum and fertilization 
followed. 
Impregnation.—The meet- 
ing place of the spermatozoon 
and ovum is generally about the 
middle of the Fallopian tube (j} 
Fig. 73). As a rule, impregna- 
tion occurs within a week after 
menstruation, but it may take 
place earlier or later ( Vide morsus diaboli). The zona pellucida, or 
covering (3, Fig. 74; and a, Fig. 76) of the ovum, is a delicate struc- 
ture. Some believe that it has several fissures, through which 
the caudal portion of the spermatozoon enters and thus fecundates 
the ovum. It has been surmized also (as white blood-corpuscles, 
under certain circumstances, penetrate the walls of blood-vessels 
and may be transformed into pus cells) that in the case of impreg- 
nation it be possible that the caudal end of the spermatozoon actu- 
ally effects the entrance through the delicate zona pellucida of an 
Fig. 76. 
Diagram of an impregnated 
ovum. 
a, Zona pellucida, or vitelline mem- 
brane. b, Yelk, c, Germinal vesicle, 
d, Germinal spot, e, Space left by 
retraction of the yelk from the vitel- 
line membrane. f, Layer of cells 
that remained from the tunica gran- 
ulosa which encircled the ovum in 
the Graafian vesicle; (a and f, greatly 
enlarged, form the vitelline mem- 
brane. k, Germ-mass, m, m, Germ- 
inal membrane, a portion only being 
indicated. 260 
REPRODUCTION. 
unfissured-ovum. As soon as impregnated, the germinal vesicle of 
the ovum changes into an embryonic cell, while yet in the Fallo- 
pian tube, and the yelk becomes cloudy and indistinguishable. 
The first step in embryonic development is the segmentation or 
cleavage of the ovum, though still enveloped in its zona pellucida. 
The transformations in the germ-cell are so rapid that by the time 
the ovum arrives at the uterine cavity the entire yelk is changed 
into a germ-mass, which becomes flattened against a segment of the 
internal surface of the zona pellucida, as indicated at h, Fig. 76. 
The aggregation of the germ-mass forms the area germinativa, which 
soon exhibits three different classes of cells, each class forming a 
separate layer; the three layers constituting a single membrane. 
Now, this membranous formation (as indicated at m, m, Fig. 76) is 
termed the blastoderm, or germinal membrane. Its external pellicle 
(ectoderm) is the serous layer; the internal layer (entoderm), the 
mucous; and the intermediate, or middle layer (mesoderm), the 
vascular. The entire embryonic structure now continues to develop 
from this blastoderm, or germinal membrane, as follows: — 
THE BLASTODERM, OR GERMINAL MEMBRANE. 
From this membrane originate the Ectoderm, Mesoderm, and 
Entoderm. 
The Ectoderm (ectoblast, or epiblast) is the external germ- 
layer, cell-wall, or yelk-membrane. From it are derived the nerv- 
ous system, dermal and epidermal tissues, voluntary motor appa- 
ratus (including muscles and bones), eyes, ears, nose, mouth, and 
anus. The mouth and anus are formed by depressions into the 
entoderm. 
The Mesoderm (mesoblast) is the middle germ-layer. From 
it are derived the involuntary motor apparatus, alimentary canal, 
heart, lungs, lymphatics and blood-vessels, vascular glands, secre- 
tory, excretory, and generative organs. 
The Entoderm (endoderm, or hypoblast) is the internal germ- 
layer. From this layer are derived the epithelial lining of the ali- 
mentary canal, air-passages, and ducts of secreting glands, and the 
endothelium of the walls of serous cavities. 
These three principal layers are intimately connected, so that 
cells of each class of tissues remain associated with others, more or 
less, to keep up during growth the connection necessary between 
the great nervous centres and the tissues of the body. It is believ- 
ed that during the early days of the embryo the cells of the central JtEPKOD U CTION. 
portions of these layers gradually separate by rapid growth, yet 
retaining sufficient the intimate relation of the different apparatus 
and systems, such as the nervous, muscular, vascular, and other 
tissues of the body. 
The ovum is lodged at the mucous membrane in the uterine cavity 
(13, Fig. 72), the most extraordinary activity of its cells soon at- 
tracting surrounding epithelial and other cells of the uterine mucous 
membrane, when the membrana decidua is developed. 
The Decidua (14, Fig. 72) originates from the mucous membrane 
of the uterus, which becomes thickened, highly vascular, and soft- 
ened, forming the special envelope (decidua) for the impregnated 
ovum. The part of this envelope lying on the muscular wall of 
the uterus is termed the decidua vera. The folds of the decidua 
wdiich grow over (next to) the ovum, are termed the decidua reflexa. 
The part of the decidua vera which takes part in the formation 
of the placenta is termed the decidua serotina. The decidua does 
not grow nor extend to the external mouth (only to the internal os) 
of the uterus, as the neck (2) becomes closed by a plug of mucus. 
The Chorion is a thin, transparent membrane, surrounding the 
foetus and amnion. It is formed from the vitelline membrane of 
the ovum, and becomes covered with villi. It is composed of two 
layers—an external vascular serous layer, or false amnion, and 
an internal fibrous layer termed allantois—which project from the 
middle and internal germinal layer, and is continuous with the in- 
testinal cavity of the embryo. Afterwards, out of the lower por- 
tion of the allantois is formed the bladder cf the foetus, and its 
upper layer furnishes a vascular membrane, which, with some of 
the large villi of the chorion, penetrate the decidua serotina, unit- 
ing it and the chorion firmly together, forming thereby the 
Placenta. Thus the combined maternal and foetal circulation is 
established, the villous portion remaining with the foetus and the 
decidua serotina with the uterus of the mother (7, Fig. 78). The 
placenta is of threefold importance—it is the organ, or channel, 
through which the circulation, nutrition, and excretion, of the foetus 
are accomplished. At birth, by the ligation of the umbilical cord, 
the haemoglobin in the ligated vessels is converted into bilirubin, 
producing jaundice in the new-born infant for the first few days. 
Extra-uterine Pregnancy.—Normally, the uterus is the re- 
ceptacle in which the new individual develops. The embryo may, 
however, form in the Fallopian tube (j, Fig. 73) or in the fringe 
(m) near the ovary in the broad ligament. Such cases are termed 262 
REPRODUCTION. 
extra-uterine foetation. That such abnormal forms of pregnancy are 
of rare occurrence may be thus explained: The spermatozoon trav- 
eling through the uterus and Fallopian tube, and not coming in 
contact with the ovum, arrives at length in a labyrinth—i, e., in 
the fimbriated extremity of the Fallopian tube (k, Fig. 73)—and 
is lodged in the wrong fringe, perishes, and shares the fate of ex- 
creted mucus. There are a thousand chances to one that this will 
be its fate. However, should it accidentally find its way into the 
fringe-tube connected with the ovary, and here fertilization be 
consummated, then the relaxed fringes stop the further progress of 
the ovum, and extra-uterine pregnancy is established. 
The fimbriated extremity of the Fallopian tube may be regarded 
as serving more than one purpose; viz., to grasp the ovary (mor- 
sus diaboli) and extract an ovum during sexual excitement, and to 
furnish a trap for the spermatozoa so as to prevent it finding the 
ovum near the ovary, thereby preventing extra-uterine pregnancy. 
Graviditas in Substantia Uteri takes place where there are 
one or more fissures, or crevices, within the mucous membrane of 
the uterus, the fertilized ovum accidentally becoming lodged in the 
depth of such a fissure. 
Twin, Triple, or Quadruple Pregnancies generally oc- 
cur when more than one ovum is liberated from the ovary or ova- 
ries, or when spermatozoa enter both Fallopian tubes and meet an 
ovum in each at the same time, or in one tube after one act of co- 
ition and in the other after a subsequent. At an average, in the 
white race twin pregnancy occurs once in about eighty times; 
triple, once in 6000; quadruple, once in about 800,000 times. 
The Mamma, or breast (A, A, Fig. 77), is a rounded eminence 
on each side of the anterior aspect of the thorax, between the ster- 
num and the axilla. It may be said that they are glands acces- 
sory to the generative system. Each mamma is provided with 
from fifteen to twenty excretory tubes termed tubuli lactiferi (F), 
terminating at the nipple (B) by minute orifices. Around the 
nipple is a colored circle, or areola, which becomes darker during 
the period of pregnancy, and remains darker in women who have 
borne children than in those who have not. The substance of the 
mamma consists of minute lobules (alveoli) containing the milk- 
secreting cells, and are clustered together in racemose or conglom- 
erate bunches, forming large lobes (D). These are situated within 
(C), which forms their envelope, composed of areolar and connective 
tissues. The ducts of (D) communicate with and discharge into REPRODUCTION. 
263 
dilatations (F) of the lactiferous ducts. The secreting lobes and 
their ducts are interspersed with areolar and fibrous tissue. The 
entire substance of the mammary gland is supplied with blood from 
the thoracic branches of the axillary, the intercostals, and internal 
mammary arteries. It is also well supplied with lymphatics and 
nerves. The nerves are branches from the anterior and lateral in- 
tercostal cutaneous. The secreting alveoli and the internal aspect 
of the walls of the lactiferous tubules are lined with epithelial 
cells. The capillary arteries furnish the blood for the nutrition of 
the gland, as well as material to the cells for the secretion of the 
milk. The elaboration of milk takes place in the secreting cells 
in the walls of the alveoli. The milk globules (fat of milk) are 
formed in the protoplasm of the epithelial cells. These milk (or 
fat) globules are much larger at the begining of lactation; such milk 
is called colostrum. In the dilatations (storehouses) (F, F, F), the 
milk accumulates during the time the child is not nursing. 
Fig. 77 
Diagram of a section of the 
mammary gland. 
A, A, Section of the skin on the sur- 
face of the gland. B, Nipple with mi- 
nute orifices of the milk ducts. C, C, 
C, Areolar and connective tissues form- 
ing roundish structures containing the 
nerve-fibrillae, lymphatics, and capil- 
lary blood-vessels; each structure con- 
tains a milk-secreting lobe (D). D, D, 
D, Milk-secreting lobes (the surround- 
ing tissues being removed), containing 
the minute alveoli clustered in hunches, 
the cells of which secrete the milk. 
F, F, F, Dilatations of the lactiferous 
ducts. The alveoli and ducts are lined 
with epithelial cells. 
The secretion of milk may be influenced by the nervous system. 
It is diminished in mental distress, and increased when the child’s 
mouth touches the nipple or the mother sees or hears her offspring. 
That the secretion of milk continues after section of the nerves 
known to supply the mammae, as claimed by some, must find an 
explanation in the fact that other nerves furnish fibres to the 
mammae not at present known to do so; or, possibly, the vaso- 
motor nerve-fibres alone exert an influence on the secretion. 264 
REPRODUCTION. 
The Nausea and Vomiting present during one pregnancy and 
not during another, in the same female, may possibly be accounted 
for by one or more of four causes: 1. Greater or less activity of 
the cells of the newly formed embryo. 2. The differences in loca- 
tion of the attachment of the ovum and development of the pla- 
centa in the uterus, which may be at the entrance of the Fallopian 
tube, at the fundus, at any part of the body, or immediately over 
the internal os, doubtless effect a difference of stimulus on termi- 
nals of nerve-fibrillse. 3. The stretching of the muscular fibres in 
the uterine wall, affecting the nerve-fibres and their end-organs 
differently, according to the place of attachment of the placenta. 
4. The difference in locality of attachment of the placenta in the 
uterus may, possibly, cause a difference in the quality and quantity 
of the lymph absorbed, which, passing into the venous circulation 
and to the heart and lungs, may, in one or in both of these organs, 
produce'a peculiar stimulation of an afferent impulse through the 
vagus, and effect reflex (efferent) action through the nervous centres 
of the origin of the phrenic and splanchnic nerves, influencing the 
stomach and diaphragm, and so establishing the nausea and vomit- 
ing sometimes experienced during gestation. 
A Mole is a more or less shapeless fleshy mass formed in the 
uterus. If it be the remains of a degenerated embryo it is termed 
a true mole, otherwise it is termed a false mole. 
Hydatidform Moles are numerous watery cysts, or conglomer- 
ated vesicles, originating from the degenerated villi of the chorion, 
each saccule growing from another with a polypoid pedicle from 
original, or principal, stems (not grape-like). They generally grow 
alternately—larger from small, and smaller from large—and ap- 
pear like strings 'with different sized nodules. Some may loosen 
and he discharged, while others remain. According to Gooch, “the 
discharged resemble white currants floating in red-currant juice.” 
Normally, the villi of the chorion grow by a process of gemmation; 
i. e., by buds. In the case of a mole, the growth is abnormal, ow- 
ing, possibly, to some fault of local circulation. The cells of each 
of the villi of which the bud is composed develop abnormally, and 
originate vesicles by repetition, and so form the hydatidform mass, 
or false moles. The hydatidform mole is not a true hydatid encysted 
vesicle, or one closed sac within another. 
An Hydatid is a vesicle, softer than the tissues of membranes, 
more or less transparent. It develops not only in the uterus, but 
Vesicular Mole—Vide Hydatidform Moles. reproduction. 
also in other organs, though without adhering to their tissue. The 
formation of a hydatid in the uterus may simulate pregnancy, and 
its expulsion is generally attended with more or less haemorrhage. 
When the ovum or some of its 
germs are malformed their deriv- 
ative cells perform abnormal 
functions, and produce a mole, 
which in time is generally ex- 
pelled from the uterus. It must 
be remembered, however, that 
moles are not always the result 
of impregnation; consequently, 
in a medico-legal sense, it is of 
importance to distinguish be- 
tween the true and false kinds. 
Discharges more or less solid 
may be mistaken for a result of 
pregnancy. Even in the virgin, 
squamous epithelium of the vagi- 
na, in the form of flakes or tubu- 
lar casts, which may be thrown 
off in greater or less bulk; a solid, 
hard fibrous structure; or a blood- 
clot may lose its coloring mat- 
ter, become dense, and enclosed 
by a membrane; or coagulated 
blood and lymph enclosed in a 
sac, very much resemble the rem- 
nant of a foetus. It is difficult to 
distinguish them from the true 
mole, and may even require the 
aid of the microscope. The most 
obstinate, painful menstruation 
(dysmenorrhcea) is often due to 
an abnormal and destructive 
membrane at the menstrual peri- 
od, which may then pass off in 
shreds, or as a. single mass the 
size of the entire uterine cavity. It may also occur independ- 
ently of menstruation, yet is always attended by haemorrhage 
and expulsive force, easily arousing a suspicion of pregnancy and 
Fig. 78. 
Diagram of the foetal 
circulation. 
1, Heart. 2, Pulmonary artery aris- 
ing at the right ventricle. 3, Arch of 
the aorta. 4, Descending aorta. 5, 5, 
Internal iliac arteries. 6,6, Hypogas- 
tric (umbilical) arteries. 7, Placenta. 
8, Umbilical vein, dividing into (9) 
the ductus venosus, and (10, 11) 
branches which enter the liver. 12, 
Inferior vena cava. 13, Superior vena 
cava. 14, 14, Vessels to and from the 
upper extremities. 15, 15, Vessels to 
and from the brain. 266 
REPRODUCTION. 
abortion. This is difficult to distinguish from an abortive discharge 
if the usual signs of pregnancy are absent and the embryo has 
escaped unnoticed, as the dysmenorrhoeal membrane resembles the 
decidua, with its smooth inner and unequal outer surfaces, that 
of non-pregnancy being more ragged, shreddy, and destitute of 
cotyledonous sacculi. Again, when the uterine membrane 
passes off as an entirety it has the three openings — two of the 
Fallopian tubes, and one of the os uteri. 
The true mole is the result of conception, the blood supply be- 
ing appropriated in excess by the decidua and surrounding 
structures, and the embryo left to decay from insufficient nutri- 
tion. It is difficult to identify a true mole, unless the liquor am- 
nion, or its sac if it be ruptured, or the remains of the umbilical 
cord, or the embryonic structures, are found—any of which estab- 
lish the fact of conception. Moles may co-exist with true pregnan- 
cy, the symptoms and expulsion resembling those of abortion. In 
a vesicular mole (hydatidform degeneration of the chorion) the 
embryo dies before the placenta is fully developed, while the villi 
of the chorion retain some of their vitality and continue their 
growth, forming serous fluid within. Such growths generally re- 
sult from dropsical swelling of the villi of the chorion, and resem- 
ble in form a bunch of grapes. The size of the vesicular bodies 
vary, however, but are attached one to another, being thus distin- 
guishable from true hydatids, which are closed sacs one contained 
within another. 
In twin conception one ovum may develop normally, while the 
other becomes a vesicular or fleshy mole. A mole may remain in 
the uterus for a long time—for years even—and it would be haz- 
ardous for a physician to assert positively that an embryo, foetus, 
true or false mole, or a true or false hydatid, had been delivered 
unless he was present at the time and thoroughly examined the 
substance delivered. Moles are generally expelled in a “delivery” 
manner, differing in this respect from a tumor or polypus. The 
latter may also resemble a mole, but can be distinguished by its 
pedicle and the absence of an ovular membranous structure. 
Menstruation.—The catamenial, or menstrual, discharges are 
commonly known as “courses,” “monthly illness,” or “periods.” 
In the female child the Graafian vesicles are small. (See Ovaries.) 
After puberty one vesicle enlarges after another in regular sequence, 
so that, normally, every twenty-eight days the largest bursts, the 
contents passing through the Fallopian tube into the uterus. This REPRODUCTION. 
267 
outflow, with the blood from the torn blood-vessels and membrane 
of the uterus, discharging through the vagina, is known as the 
menstrual discharge. The ripening and dehiscence of Graafian 
vesicles take place during the child-bearing period. Astonishing 
freaks of nature are sometimes observed. According to Talten “a 
woman of the age of 70, a widow for 20 years, was found to 
be pregnant.” Menstruation plays only a secondary part in the 
phenomenon of ovulation. According to Leishman, a woman who 
had married at twenty-seven menstruated for the first time two 
months after her eighth labor; another woman had no discharge 
until after her second marriage, at the age of forty. Garus refers 
to a child who menstruated at the age of two years, became preg- 
nant at eight, and lived to an old age. A woman may become 
pregnant without ever having menstruated, or during the nursing 
period before the menses reappear. 
The menstrual discharge is haemorrhagic, the blood becoming 
mixed with the mucus and other secretions of the vagina and ad- 
jacent parts. Before and after the rupture of one or more Graafian 
vesicles, the uterus, ovaries, and Fallopian tubes, especially the 
mucous membrane of the uterus, become congested, the capillaries 
distended, its glandular follicles are more active, and a mucus 
discharge takes place before and after the bloody flux. The 
proliferation of the cells, and fatty degeneration, together with the 
congestion, compress the capillary veins, and, in tearing 
carry along the capillary vessels and part of the membrane. The 
epithelial covering and superficial mucous membrane are thrown 
off, and even blood oozes from the utricular follicles and the Fal- 
lopian tubes. The capillar}1, vessels hang denuded in detached 
loops in the uterine cavity, and may be discovered in the dis- 
charge. The slight rupture of blood-vessels of the Graafian vesicles 
on bursting also adds to said discharge. 
Leishman states that Dr. Tyler Smith had several opportunities 
of examining the uteri of women wdio had died during menstru- 
ation. He found that the appearances presented were similar to 
those observed after abortion. In one case the mucous membrane 
in the cervix was perfect, but at the os uteri internum (3, Fig. 72) 
it ceased as abruptly as if dissected off writh a knife above that 
point, and blood was oozing at numerous points from broken ves- 
sels in the submucous tissue. This may be of importance in a 
medico-legal sense. According to the theory of Reichart and others, 
“before the ovum is discharged during the process of ovulation the 268 
REPRODUCTION. 
uterine mucous membrane becomes more vascular, congested, 
spongy, and thicker, in which state it is termed membrana decidua 
menstrualis; that it is then in a more favorable condition to receive, 
retain, and nourish a fertilized ovum coming in contact with it. If 
the ovum be not fertilized, then the membrane degenerates and a 
bloody menstrual discharge follows.” According to this view, the 
discharge is a sign of non-pregnancy. Hence, pregnancy is to be 
calculated from the time between the last menstruation and the 
time when it normally should recur. Sometimes, however, ovula- 
tion and the formation of the membrana decidua menstrualis occur 
independently .of each other, and menstruation may recur without 
ovulation, and vice versa. 
In the opinion of the writer, that process may work differently. 
During ovulation the extremely vascular, congested, and thickened 
membrana decidua menstrualis degenerates, the capillary vessels 
are torn asunder, and bleeding follows. Now comes the point, 
however, that, when a fertilized ovum is lodged anywhere in the 
uterus, the uterine membrane is relieved, as it were, as a great 
part of the blood of the uterine artery is attracted to and supplies 
the extremely active cells and newly forming tissues of the embryo, 
when generally no further menstruation occurs. Periodical men- 
struation may continue, for a time, however, if the capillaries of 
the membrane should become more or less congested and the mem- 
brane degenerate. Again, if the spermatozoon travels the entire 
length of the Fallopian tube, meeting the ovum near the ovary in 
the tube-fringe (m, Fig. 73) leading from the ovary to the Fallopi- 
an tube, and the ovum becomes fertilized in the tube-fringe, then it 
remains on the spot in the tube, and we have a case of extra-uterine 
pregnancy. When this occurs the embryo is supplied from the 
ovarian artery, and menstruation from the uterus may continue as 
usual from the parts supplied by the uterine artery. ( Vide Extra- 
uterine Pregnancy.) 
The cause of menstruation is generally associated with, but does 
not depend on, the maturation of one or more Graafian vesicles 
and the discharge of ova. Why it recurs in the human female at 
regular periods of twenty-eight days, when one or more Graafian 
vesicles mature; and similarly in certain of the lower animals; and 
in some animals a cluster ripens; and again, in others the ovulation 
occurs in periods of a year—these are facts which no one can 
at present explain. 
At the cessation of the menstrual discharge in the human female, REPRODUCTION. 
269 
which occurs generally at the age of about forty-five, the uterus 
atrophies and the ovaries shrink, denoting the termination of the 
reproductive function. This crisis in the life of woman is termed 
the menopause. 
Entozoa are animal organisms living within other animal 
bodies, from whose tissues they derive nourishment; as, for example, 
worms in the intestines, or trichinae spiralis in the muscles. The 
trichinae spiralis are sexless, encysted, wormlike parasites about 10 
millimetres in diameter, found especially in the flesh of animals of 
the porcine type. If such flesh be used as food (insufficiently 
cooked) and the cysts digested, the parasites become liberated and 
multiply in the small intestine, the walls of which they permeate, 
entering the different parts of the muscular tissue and setting up 
serious diseased conditions. 
Infusoria, or water animalcula, are found generally during 
the summer months, if the water be exposed in a moderately warm 
atmosphere, though the water be clarified, distilled, or boiled. 
The infusoria reproduce their species by eggs in special generative 
organs, which are fecundated by union of the sexes. 
Life Functions pass through unceasing changes until com- 
pletely suspended, the particular kind, or species of organisms 
remain, ivhile the individual perishes. 
Plants.—In certain plants the two sets of reproductive organs 
are found together, the ovules being fertilized by the pollen of the 
same structure. After fertilization the ovules are set free and 
thrown upon their own resources, to draw from the surrounding 
elements the materials for their growth and development. CHAPTER XXVII. 
MISCELLANEOUS. 
The Connective Tissues are of great variety. Their function 
is that of supporting the frame and holding together the various 
other tissues and organs. They are divided into mucous and 
retiform (net-like) connective tissues, white and yellow fibrous tis- 
sue, cartilage, and bone. The cells of all these tissues have the 
property of secreting material for the nutrition and repair of their 
own and of the intercellular substance. The younger the tissue 
the more numerous are the cells contained in it; while in old age 
the intercellular substance predominates, the cellular portion being 
relatively less. 
Fibrous Tissues, especially the non-elastic or white tendin- 
ous, are, as a rule, easily affected by chemical reagents. Weak 
acids cause them to swell and become indistinct; consequently, a 
super-acid condition of the system causes disease. 
Cartilage-cells secrete an intercellular substance, which in 
some parts remains quite soft, while in other parts it becomes hard. 
Bone is, in some respects, the most remarkable of the connect- 
ive tissue group, its cells having the peculiarity of attracting and 
secreting a great quantity of earthy, or inorganic, matter. This 
inorganic matter imparts to bony tissue its great strength and 
hardness, and enables it to support the body. Bone contains also a 
quantity of fat, cells, nerves, and blood-vessels, and is covered on the 
outside with a tough vascular coat, termed the periosteum. Where 
bones are in relation at the joints, their articular surfaces are covered 
with cartilage. ( Vide Lime Phosphate.) 
The Periosteum is a fibrous membrane on the external surface 
of the bones. It imparts strength to the bone and affords a suitable 
attachment for muscles. It is well supplied with arteries, thereby- 
furnishing nutrition to itself and the bone. It contains also veins, 
nerves, and lymphatics. In periostitis, pus may collect between the 
bone and periosteum, causing pressure on the vessels, so that the 
outer layers of the bone are soon deprived of nutrition, resulting 
in necrosis. MISCELLANEOUS. 
271 
Gangrene.—Interruption of the return of venous blood is sel- 
dom a cause of gangrene. This fact is especially noticeable in 
women during or after pregnancy, when the veins of the lower 
extremities are sometimes enormously enlarged. About the only 
instance where a stoppage leads to gangrene is that of a hernial 
sac, where the veins are compressed sooner than the arteries. In- 
terruption or entire stoppage of the normal exchange of arterial 
and venous blood terminates the life of a part (gangrene). A 
tumor pressing on arteries, or continuous convulsive contractions 
of their muscular coat, even the continuous use of too large doses 
of ergot, may produce gangrene. Again, the cause of interruption 
of the blood circulation may have its seat in the capillaries, as by 
exudations or new formations in the parenchyma of the tissues of 
the part affected, producing compression on the blood-vessels. Other 
causes of a mechanical or chemical kind, such as crushing, concus- 
sion, desiccation, corrosion, or ferment poisoning, produce, by their 
violent disturbance of the molecular arrangement of the tissues, a 
disturbance which is incompatible with the continuance of vital 
action in the part affected. ( Vide Mortification.) 
When the amount of arterial blood flowing through a certain 
part of the body falls below the normal quantity, the nutrition of 
such part suffers; if the current ceases entirely, so does the nutri- 
tion. Disturbances of the circulation are most frequently caused 
by obstruction in the afferent arteries. This may arise from a 
thrombus, or disease may cause a gradual diminution of the lumen 
of the vessel, whereby the heart’s propulsive force becomes much 
reduced in the larger arterial trunks. Disease of the heart’s mus- 
cle or general debility may also retard the blood current. 
In Gangrsena Senilis, or the dry gangrene of old age, which 
commences at the fingers or toes and gradually extends upwards, 
caused by defective circulation, both forces—the heart and the 
blood-vessels generally—act conjointly; that is to say, there is a 
retrograde change in the heart’s muscle, and disease of the vessels. 
New Formations—Cancer.— By a new formation is meant 
an abnormal increase of development, or excessive growth of tissue. 
Virchow, writing on cell life, says, “Wherever celis exist in the 
organism they are the offspring of other cells which no longer exist; 
the new cells are the heirs of the mother cells, yet not always of 
their peculiarity and vital properties.” Here is condensely expressed 
the substance of many volumes; for in this new formation the 
original simple cell is multiplied, the nucleus elongated, and then 272 
MISCELLANEOUS. 
constricted in the centre until the connection is broken. The 
nucleus, in dividing, brings about a division also of the nucleolus; 
then there are two cells instead of one; these two produce four; these 
eight, and so on ad infinitum, if unobstructed. Sometimes this 
occurs rapidly, as from an injury, causing a tumor or cancerous 
growth in a short space of time. An increase of protoplasmic force 
from within outward, or a supply of defective pabulum to the cells, 
may cause a division of the nuclei, with a similar result. The form 
of the growth depends upon the the space and kind of tissue it oc- 
cupies. The cells of such growth are termed giant cells, because 
they are larger than other cells and almost without limit in growth. 
When imbedded in soft, yielding tissue, the growth produced is gen- 
erally round; but if imbedded in a fibrous structure, then it is 
furnished with processes at its periphery, continuing into the soft, 
yielding interspaces of the fibrous structure—the so-called roots of 
cancer. This abnormality is an example of the means of unlimited 
multiplication, primarily, from a single giant cell. 
Of all tissues of the body the blood contains the largest percent- 
age of water; therefore, in death it decomposes more rapidly than 
any other tissue. Soon after death the coloring matter leaves the 
blood-corpuscles, and colors first the serum, and then the walls of the 
vessels and loose cellular tissue around them. Soft tissues, on dis- 
integrating, become swollen, the degree of tumefaction, or swelling, 
depending entirely upon the quantity of water contained therein. 
During life there is another increase of the tissues called fatty 
degeneration, wherein the nucleoli of the cells are changed. These 
nucleoli become enlarged with fat globules, gradually filling the 
entire cells, which then increase in size three or four times. Those 
that have been previously round, cylindrical, flat, or of spindle 
form, assume a different shape, and are termed granular corpuscles, 
being globular aggregations of fat-globules held together by inter- 
mediate albuminous substance. When a large number of such 
granular corpuscles are together the fluid or tissue in whose inter- 
stices the granular corpuscles are suspended or deposited is of a 
yellowish tint; as in colostrum, which is a viscid fluid. If left 
standing, this fluid soon separates into a transparent serous fluid 
and a cream-like mass consisting almost entirely of granular cor- 
puscles produced in the mammary gland by fatty degeneration, 
the minute particles of the corpuscles not having been completely 
broken up, causing the colostrum to appear yellowish or oily. In 
fatty degeneration of the tissues the albuminous substance referred MISCELLANEOUS. 
273 
to is surrounded by the alkaline blood, and its alkaline salts, which 
are abnormally increased, act upon and dissolve the fat-globules. 
The albuminous substance is then no longer able to hold the fat- 
globules together, when they disintegrate or break up. The farther 
this disintegration of fat-globules proceeds the whiter the surround- 
ing tissue appears, the cells, as previously stated, swelling up and 
rupturing on account of the overproduction of fat. Rindfleisch 
says, “Even nerves and blood-vessels become subject to fatty degen- 
eration, the muscles of the heart being most liable.” 
Dissolution of the Human Body begins as soon as the 
functional interdependence of the different organs ceases, the parts 
then becoming like inorganic matter. The only force keeping them 
in form is cohesion. This, however, exerts a limited and tempor- 
ary power on human organic matter, owing to the extraordinary 
abundance of water present. At death decay begins slowly, the 
process of dissolution accelerating with the lapse of time. 
Spontaneous Generation is not admissible even in the case 
of bacteria, including their various varieties. Heat exerts in vary- 
ing degrees a preventive action on their appearance. Schizomycetes 
(minute vegetable organisms—saprophytes, which some claim, be- 
long to the algae) have the peculiarity of being devoid of chloro- 
phyll, and are endowed with mobility in the absence of oxygen. 
Bacteria, in one variety or another, develop in all kinds of de- 
caying animal (ptomaines) and vegetable matter, and when devel- 
oped may cause live animal tissues, of greatly diminished vitaxiiy, 
to decay. Organisms described as micrococcus, bacterium, and bacil- 
lus are, possibly, varieties of the same species only. 
Ptomaines.—Ptomaine is the principal acting substance of 
dead animal tissue (carcass). It is to the dead tissue what the pro- 
teid is to the living. Both proteid and ptomaine differ according 
to the composition of the tissue. Again, both differ according to 
the condition of the tissue; for instance, the proteid! differs much 
in the plethoric condition of the body from the anaemic. The pto- 
maine differs much according to the decomposition of the dead tis- 
sue. In the ptomaine organisms easily develop termed pathogen- 
ytes, which exercise an important influence in many pathological 
conditions. Some pathogenytes may be transient, others more per- 
manent and severe. These organisms are very apt to form in a 
wound, especially in a defective mucous membrane, or in a bed-sore 
for instance, in which the diminished vitality of the patient favors 
their formation and absorption. These organisms may easily be- 274 
MISCELLANEOUS. 
come absorbed by the blood-capillaries direct, or through the 
lymph-vessels enter and poison the blood, as in the case of diph- 
theria (diphtheritic cocci) from decayed mucous membrane of the 
tonsils, for instance. When pathogenytes are developed, or intro- 
duced with food, the effect is apparent, especially in the intestinal 
canal, illustrated by the introduction of the tyrotoxicon of decayed 
cheese or other food, and may, in legal investigations, be of great 
importance in clearing up certain mysterious poisoning cases, which 
might be mistaken for the willful admixture of poisonous drugs. 
As long as the pathogenytes affect a wound only they can be de- 
stroyed with antiseptics. Several kinds of said organisms may be 
combined in one ptomaine, can live and multiply, and by the blood 
be carried from one part of the tissue to another. They may ag- 
gregate in the capillaries of an organ, tissue, or gland, and become 
absorbed again, producing what is termed Infection. The blood- 
poisoning from wounds is often believed to be due to absorption of 
pus-cells and is termed pyaemia, but in reality very often, possibly 
always, is due to poisoning from micro-organisms of a ptomaine. 
AVhen the ptomaine organisms develop quickly within the system, 
or enter it very numerously by Contagion, they may produce 
death in a few hours. Their slow development and smaller num- 
ber in the system may produce hectic fever. The relapsing, con- 
tinued, remittent, periodic, and intermittent fevers, respectively, 
may possibly be due to pathogenytes of ptomaines developed some- 
where in the mucous membrane—most likely in the alimentary 
canal. The time may not be distant when the primary origin of 
Koch’s bacillus may be traced not to the lungs, but to defective 
mucous membrane either in the bronchial tubes, nose, or intestine. 
It is by no means necessary that the primary origin in all cases 
be in the same locality. 
-fflther, or Ether, is an extremely subtle, elastic substance 
which is supposed to pervade all space as well as all bodies. It 
may reasonably be assumed to be a simple form of gas, which on 
account of its extreme tenuity is undetectable by any process at 
present known to science. It does not enter into combination with 
other substances; therefore its quantity, quality, and action always 
remain constant. Assuming the atomic theory to be the correct 
one, {aether forms the interstitial medium between the atoms and 
molecules of all gases, fluids, and solids; entering the inter-atomic 
and molecular spaces on the expansion of these bodies and reced- 
ing on their contraction. MISCELLANEOUS. 
275 
Still-born.—In determining whether a dead infant has breathed 
or not, Moreno says “that the ciliated cylindrical epithelium of 
the respiratory tract extends down to the terminal bronchioli,. 
where, in an infant that never breathed said epithelium is cubical, 
but as soon as respiration begins, it is transformed into flat epithe- 
lium. That the change not being a mechanical, but a physiolog- 
ical occurrence. Hence, by the aid of a microscope it might be 
determined whether the infant, whose lungs contain air, had 
drawn it in by inspiration, or if it had been forced in during an 
attempt at artificial respiration.” 
Artificial Respiration is recommended by Sylvester as fol- 
lows: “The patient is laid on his back on a plane, inclined a little 
from the feet upward; the shoulders are gently raised by a firm 
cushion placed under them; the tongue is brought forward so as to 
project partly from the side of the mouth. The operator then 
grasps the patient’s arms, raising them above the head. This action 
imitates inspiration. The patient’s arms are then turned down and 
finally pressed for a moment against the sides of the chest. A 
deep expiration is thus imitated. These two reversing movements 
should be perseveringly continued at the rate of about 15 to 18 
times in a minute. In addition the operator may pay attention to 
the following: 1. That all obstruction to the passage of air to and 
from the lungs be at once removed; that the mouth and nostrils be 
cleared from foreign matter or mucus. 2. A dash of hot water 
(120° F.) or cold water to the face for the purpose of exciting res- 
piration. 3. That the temperature of the body be maintained by 
friction or warm blankets. 4. In case of drowning, in addition to 
the foregoing suggestions, first of all place the body with the face 
downward, the face hanging a little over the edge of the table or 
board, and the body raised at an angle of about 30 degrees, so that 
the head is lower than the feet. Open the mouth and draw the 
tongue forward, and allow the water from the lungs to escape 
quickly, which may be assisted by pressure on the back, then to 
resort to the foregoing artificial respiration.” GLOSSARY. 
Abdominal reflex. Contraction of the abdominal muscles upon stimulation 
(tickling) of the skin over the side of the abdomen or sole of the loot. 
Abducens. Sixth pair of cranial nerves. 
Abduction. Drawing outward from the median line of the body or of the 
limb. 
Aberration. Wandering from; dispersion of the rays of light in passing 
through a lens; passage of a fluid into a part not appropriate for it. 
Absorbents. Capillary veins and capillary lymphatics. 
Absorbent system. Veins and lymphatics. 
Abortion. Accidental or willfully induced premature birth. 
Abscess. A circumscribed collection of pus in tissue. 
Absorption. The taking in or sucking up by the tissues; imbibition. 
Acarus. Mite; a minute living organism. 
Accessorius. The spinal accessory nerve. 
Accessory. Accompanying or taking part with another, as the spinal 
accessory nerve with the pneumogastric nerve. 
Accommodation. The power of the crystalline lens to increase or diminish 
its convexity so as to focus on the retina the rays of light reflected from 
objects at varying distances within a range of from (about) 4 to (about) 225 
feet from the eye. This accommodation of the lens is caused by nervous 
reflex action for contraction or relaxation of the ciliary muscle, ciliary and 
suspensory ligaments of the eye. 
Acetate. A salt formed by the union of acetic acid with an alkaline, 
earthy, or metallic base. (See Base and Salt.) 
Acetic. Pertaining to acidity, sourness. 
Achromatic. Free from chromatic aberration; destitute of color. 
Acidity. Sourness. 
Acinous gland. Small gland composed of saccules in the form of a bunch of 
grapes. 
Acinus (pi. acini). Ultimate lobule of a racemose gland. 
Acoustic. Relating to hearing or sound. 
Acrid. Irritant. 
Acupuncture. Puncturing the skin, as with needles. 
Acusticus. Auditory nerve. 
Acute. (Lat. acutus). Relating to disease of short duration; sharp; pointed; 
Adam’s Apple. Pomum Adami, or angular projection on the anterior aspect 
of the thyroid cartilage. 
Adducens (adducent). Relating to adduction. 
Adduction. Bringing, drawing, or attracting inward toward the median line 
of the body, organ, or of the limb. 
Adenoid. Resembling a gland or its tissue. 
Adenoma. Tumor originating in and composed of glandular tissue. 
Adhesion. Attraction between unlike molecules. (See Cohesion.) 278 
GLOSSARY. 
Ad infinitum. To infinity; unlimited capacity, extent, or energy. 
Adipose. Relating to fat; fatty. 
Adolescence. The period from puberty to legal majority. 
Adventitia. Outer coat of blood-vessels. 
Adynamic. Loss of vital power or muscular strength. 
Aer. Air; gas. 
Aeration. Arterialization. 
Aeriform. Like air; gaseous. 
ASsthesis. Perception; sensibility. 
AEther. See JEther in chapter on Miscellaneous. 
etiology. The science of causes; doctrine of the causation of disease. 
Afferent. Carrying to. 
Afferent nerve-fibres. Carrying sensory impulses to either nervous centres 
of the cerebral convolutions to inform the sensorium, or to excite in other 
nervous centres reflex (efferent) impulses for motor action of an organ, or 
for both of these actions. 
Affinity. Attraction; relationship; tendency toward. 
Afflux. Excessively flowing to. 
After-image. A visual impression that persists on the retina after seeing an 
illuminated object. 
Ageusia. Want of taste. 
Agglomerate. Crowded together; aggregate. 
Aggregation. A collection; an assemblage. 
Agglutition. Inability to swallow. 
Agminate. Grouped together. 
Agminate glands. Peyer’s patches. 
Ague. Intermittent fever. 
Air-cells. Minute dilatations of the terminals of air-passages in the lungs. 
Ala (pi. alae). Awing; armpit. 
Ala cinerea.Wing ash-colored; vagus area. 
Alar. Wing-like. 
Albescent. Growing white. 
Albuginea. A thick layer of white fibrous tissue investing viscera. 
Albuginea ovarii. Tunica albuginea of the ovary. 
Albugineous tissue. Fibrous tissue of a yellowisli-white color. 
Albumen. White of egg. 
Albumin. Albuminous (nitrogenous) proximate principle, always containing 
sulphur. 
Albuminate. A combination of albumin with a base. 
Albuminoid. Proteid. 
Albuminose. Albuminous matter, converted during digestion, fitted to dif- 
fuse through animal membranes. 
Albuminous. Relates to animal and vegetable food containing albumen 
mixed with other nutritious substances. 
Albuminuria. Albumin in urine; Bright’s disease. 
Alga (pi. algae). Seaweed; an order of cryptogamic plants. 
Algesia. Morbid sensibility to pain. 
Aliment. Nourishment; food. 
Alimentary. Relating to aliment, or to the alimentary canal. 
Alimentary canal. Digestive canal, extending through the body from the 
mouth to the anus. 279 
GLOSSARY. 
Alkali. That which is generally known as soda, potash, or ammonia, and 
forming a neutral substance with an acid. Lussac classifies the alkalies as 
follows: 
I. Metallic bases, as potash, soda, and lithia, containing oxygen. 
II. Non-metallic bases, as ammonia, not containing oxygen. 
III. Vegetable alkalies or alkaloids, as quinine, morphine, strychnine, 
etc.; all contain nitrogen in combination with oxygen, hydrogen, and car- 
bon. These are the active principles of certain plants. 
Alkaline. Relating to or having the property of an alkali. 
Alkaloid. A salifiable base of certain vegetables, existing therein as a prox- 
imate principle. (See alkali.) 
Allantoid. Condition like force-meat. 
Allantois. Chief component part of the placenta, being the internal fibrous 
layer of the chorion surrounding the foetus and amnion. 
Aloe. An inspissated juice of a certain plant. 
Alopecia. Loss of hair. 
Alveolus (pi. alveoli). A small cavity or sac. 
Alvine. Pertaining to the abdomen or intestines. 
Alvus. Belly. 
Amaurosis. Loss of vision. 
Ambiopia. Double vision. 
Amblyopia. Dimness of vision; partial amaurosis. 
Amenorrhcea. Absence of the menses due to some morbid condition. 
Amentia. Imbecility of mind; total absence of intellect. 
Ametropia. Defective refraction in the eye. 
Amide. A compound of an acid radical (atom) with the compound formed by 
one of nitrogen and two of hydrogen (N H2), derived from ammonia. Am- 
monia thereby loses one radical of hydrogen. 
Ammonia. A gaseous compound of one element of nitrogen and three of 
hydrogen (N H3), existing in air and soil, the product of decomposition 
and putrefaction of organic tissues. 
Ammoniacal. Containing or pertaining to ammonia. 
Amnesia. Forgetfulness; total or partial loss of memory. 
Amnion. A membranous sac forming part of the placenta enveloping the 
foetus in the uterus. 
Amoeba (pi. amoebae). A unicellular organism composed of a nucleated mass 
of protoplasm. 
Amoeboid. Relating to or resembling amoeba, especially in movements and 
changes of shape. 
Amorphous. Without form ; shapeless; matter in a solid state when exhib- 
iting non-methodical arrangement of its molecules; not crystalline. 
Amplitude. Extent, fullness, strength, especially as applied to sound or 
pulse. 
Amplus. Ample; large; roomy; spacious; great. 
Ampulla (pi. ampullae). Oblong vessel or flask, enlarged or puffed out; 
flask-shaped enlargement of a membranous tube, as that of a semicircular 
canal. 
Amylaceous. Containing or pertaining to starch; starch-like. 
Amyloid. A compound formed in the body from starchy matter. 
Amylum. Starch. 
Anabolic. Relates to anabolism. 
Anabolism. Constructive process; building up tissues from nutritive sub- 
stances; assimilation. (See Metabolism and Katabolism.) 280 
GLOSSARY. 
Anaemia. Insufficient number of, or defective, red blood-corpuscles in the 
blood, or a local or general want of blood in the body. 
Anaemic. Relating to anaemia. 
Anaesthesia. Impairment or absence of sensation of a part of, or of the 
entire, body—caused either by disease or by the use of an anaesthetic. 
Anaesthetic. A substance or agent that impairs or destroys (paralyzes) sen- 
sation ; pertaining to or inducing anaesthesia. 
Analgesia. Loss of sensation to pain, but not to tactile impressions. 
Analogus (analogous). Resembling; similar to. 
Analysis. The act of dissolving any substance ; separating constituent ele- 
ments of a compound. 
Anasarca. General dropsy. 
Anastomose (anastomosis). Union or communication with each other, as of 
the arteries, veins, lymphatics, or fibres of a nerve with another nerve; 
inosculation. 
Anatomic element. The smallest natural division of the organism. 
Anatomy. The art of dissecting organized bodies. 
Anchylosis (ankylosis). Immobility of a joint due to abnormal adhesions. 
Aneurism. Bulging or tumor-like dilatation of the coats of a vessel; several 
aneurisms may thus anastomose. 
Angina. Severe choking affection. 
Angina pectoris. Paroxysms of intense pain in the praecordial region and 
heart, with a sense of suffocation, diminished pulse, and altered rhythm. 
Angioma. Tumor, composed principally of vessels. 
Ani. See Anus. 
Animalculum (pi. animalculla). A minute organism. 
Annular. Ring-like. 
Ano. See Anus. 
Antacid. That which counteracts acidity. 
Antagonism. Opposition; resistance; counteraction. 
Anteflexion. Bending forward, usually referring to the uterus. 
Anterior. That which is in front; forward aspect. 
Antero. Anterior—used in the formation of compound adjectives. 
Anteversion. A displacement forward of the fundus of the uterus. 
Antidote. A remedy which counteracts or removes the effects of poison. 
Antiphlogistic. A remedy opposed to or which checks inflammation. 
Antipyric. A remedy which checks or prevents the formation of pus. 
Antiseptic. An agent opposed to putrefaction, or which prevents the growth 
of organisms in the tissues. 
Antispasmodic. A remedy which relieves and prevents spasms. 
Antizymotics. An agent opposed to fermentation. 
Anuresis. Inability to urinate. 
Anuria. Suppression of urine. 
Anus (gen. ani). The termination of the rectum. 
Aorta. The largest artery of the body, originating at the heart. 
Aortic. Relating to the aorta. 
Aperture. An opening; a passage. 
Apex. The summit or extreme point. 
Aphasia. Loss or disturbance of the power of speech. 
Aphonia. Loss of voice. 
Apncea. Want of breath; extreme inability of respiration. GLOSSARY. 
281 
Apomorphia. An alkaloid prepared from morphine and hydrochloric acid. 
Aponeurosis. A thick, white, shining expansion of tendons; a sheet of ten- 
dinous fibres. 
Apoplexy. Sudden paralysis of sensation and motion, resulting usually 
from hemorrhage in the brain. 
Apparatus. A combination of organs performing harmonious and definite 
functions, as the circulatory apparatus formed by the heart, arteries, cap- 
illaries and veins. 
Appendix. An accessory part or a continuation of an organ. 
Apposition. The act of bringing together; of being properly together. 
Aqua. Water. 
Areola (pi. areolae). Interstitial space between fibres of the most delicate 
connective tissue. 
Areola mammae. The circular brownish color around the nipple. 
Areolar tissue. Most delicate connective tissue, having areolae freely commu- 
nicating with each other, especially when blown up with air or when dis- 
tended with fluid. 
Argentum. Silver. 
Argenti Nitras. A salt prepared from silver, nitric acid, and water. 
Argyria. Grayish discoloration of the skin resulting from long-continued 
internal use of argenti nitras. 
Arrector. Lifting up; raising. 
Arrectores pili. Erector muscles of the hair. 
Arteria. Artery. 
Arterialization. The imbibition or taking up of oxygen by the venous 
blood, making it arterial blood. 
Articulation. The approximation of the cartilaginous ends of bones; a 
joint; also, relating to the proper enunciation of words. 
Arytaenoid. Funnel- or pitcher-shaped. 
Arytaenoideus. Kelating to arytaenoid muscles, cartilage, nerves, etc. 
Ascites. Abdominal dropsy. 
Asphyxia. Inhibition of respiratory movements; suffocation. 
Assimilation. The conversion of nutritious matter into the proper organic 
tissues of the body. 
Asthenia. Debility; want of strength. 
Asthenopia. Muscular and accommodative weakness of the eye. 
Ataxia. Inco-ordination of muscular movements. 
Atlas. First cervical vertebra. 
Atom. The smallest part of matter that can take part in a chemical change. 
Atony. Diminished muscular tone; want of strength. 
Atrophy. Wasting of a tissue, or of the whole or a.part of the body. 
Atropia. The alkaloid of belladonna. 
Attolens. Lifting upward. 
Attrahens. Drawing forward or towards. 
Auditorius. Auditory nerve. 
Auricle. External ear; right auricle of the heart. 
Auricles of the heart. The two superior cavities of the heart. 
Automatic. Producing movements without external aid; self-acting; self- 
regulating. 
Axilla (pi. axillae). Armpit. 
Axis. A right line passing through the center of, a body on which it 
revolves; the second cervical vertebra is so named, from the fact that it 
forms the pivot upon w'hich the head rotates. 282 
GLOSSARY. 
Axis-cylinder. Central filament of a nerve-fibre. 
Axis-cylinder process. The prolongation of a nervous centre-cell—believed 
not to be connected with the axis-cylinder of a nerve-fibre. 
Arachnoid. A delicate serous membrane, resembling a spider’s web, be- 
tween the dura mater and the pia mater. 
B 
Bacillus (pi. bacilli); (From baculum, a stick or rod). A minute rod; rod- 
like bacterium. 
Bacterium (pi. bacteria). A little rod; a micro-organism of rod-like form; 
genus of schizomycetes, occurring in decomposed animal and vegetable 
matter. 
Basal ganglia. The optic thalami and corpora striata together. 
Base. Foundation; resting on; chemically, principal element of a compound; 
any substance that will neutralize an acid. 
Basement membrane. A delicate, structureless lamella beneath the epi- 
thelium. 
Basilar membrane. The membranous spiral lamina of the cochlea that 
stretches Irom the labium tympanicum to the crista basilaris. 
Bifurcation. Dividing into two branches; place of division. 
Bioplasm. Living matter; protoplasm. 
Bipolar. Having two poles or prolongations. 
Blastoderm. Layers of cells in the segmented ovum covering the yelk; cells 
which form the germinative area; germinal membrane. 
Bowman’s capsules. Envelopes of the glomerules in the kidney. 
Bronchial tube (pi. bronchial tubes). Tubal continuations from the bronchi 
to the bronchioli. 
Bronchiolus (pi. bronchioli). Capillary continuation of the bronchial tube. 
A single membrane destitute of cartilaginous rings. 
Bronchitis. Inflammation of the bronchi. 
Bronchus (pi. bronchi). One of the two divisions of the trachea. 
Bubo. Inflammatory enlargement of a lymphatic gland, especially of the 
groin or axilla. 
c 
C. Abbreviation of centigrade and of carbon. 
Cachexia. Defective nutrition, as occurring in syphilis and in Canoer; 
depraved condition of the body. 
Cadaver. A carcass, or dead animal body. 
Caecum. Ending blindly, as a sac with only one opening. 
Calamus scriptorius. A writing pen; a small pen-shaped tubercle at the 
inferior angle of the fourth ventricle. 
Calcareous. Pertaining to lime. 
Calcis. Lime. 
Calculus. A stone-like formation in the body. 
Callosus. Hard; thick-skinned. 
Callous. Indurated; hard. 
Callus. The flexible bony substance formed around the ends of a fractured 
bone during the process of repair. 
Caloric. Warmth; heat. 
Calyx (pi. calyces). A cup; cup-like cavity into which the renal papillae 
project. 
Canalis reuniens. A short canal connecting the ductus cochlearis (scala 
media) with the saccule. 
Canula. A small tube. GLOSSARY. 
283 
Capillary. A hair-like tube or vessel. 
Carbohydrate. A compound of carbon, oxygen, and hydrogen. 
Carbon. A non-metallic element found in all organic compounds; coal. 
Carbonate. A salt formed by the union of carbonic acid with a salifiable 
base. When the base is imperfectly neutralized by carbonic acid the salt 
is termed a subcarbonate; when there is an excess of acid it is termed a 
bicarbonate. 
Carbonic acid. A compound of one atom of carbon and two of oxygen. In 
the animal body it holds in combination ammonia and organic matter. It 
has a slight odor and a pungent, acidulous taste, and acts as a powerful 
stimulus in the animal economy. Carbonic acid gas artificially introduced 
acts as a sedative. 
Carcinoma. A tumor consisting principally of epithelial elements; cancer. 
Cardiac. Relating to the heart. 
Carotid. An artery on each side of the neck supplying blood to the head; so 
named because of its slow pulsation during sopor, coma, lethargy, and 
carus. 
Catalepsy. Complete suspension of irritability and volition, with rigidity 
of the voluntary muscles, the limbs and trunk preserving the different 
positions given them. 
Cataract. Opacity of the eye-lens or of its capsule. 
Caudal (Lat. cauda, tail). Pertaining to the extremity, or tail-end. 
Cellular. Pertaining to or consisting of cells. 
Cellulose. Cell-matter and fibres of plants isomeric with starch. 
Centigramme. A French weight; the l-100th part of a gramme, designated 
0.01. 
Centigrade (abbr. C.). A scale to measure temperature, based on the deci- 
mal system. 
Centimetre. One-hundredth of a metre; 0.39371 inches. 
Centre. An aggregation of gray nervous cell-matter. 
Cerebellum. The posterior lower part of the brain; small brain. 
Cerebro-spinal. Pertaining to the bra:n and spinal cord. 
Cerebrum. The upper and largest part of the brain. 
Cervical. Pertaining to the neck between the head and chest or to the neck 
of the uterus. 
Cervix. Neck. 
Chemical change. A change that alters the identity of the molecule. (See 
Physical change.) 
Chlorophyll. A dark-green and essential element of vegetation, composed 
of hydrogen, nitrogen, oxygen, and carbon, imparting the green color to 
foliage and transforming plant-food into vegetable matter. 
Chlorosis. Green-sickness characterized by anaemia, languor, palpitation of 
the heart, and deficiency of red blood-corpuscles, generally affecting young 
females. 
Cholesterin. A fatty substance occurring in the brain, nervous system, and 
blood; excreted in bile, and occasionally in the urine of fatty kidney. 
Chondrin. The essential constituent of cartilage. 
Chondrus. Cartilage. 
Chorda tympani nerve. A branch of the facial at the Fallopian aqueduct, 
passing under the mucous membrane of the tympanum (middle ear), then 
joining the lingual nerve to confer the sense of taste to the anterior two- 
thirds of the tongue. 
Chorea. St. Vitus’ dance; irregular involuntary twitching and contraction 
of muscles. 284 
GLOSSARY. 
Chromatic. Pertaining to color. 
Chronic. Long-continued, slow, tedious progress. 
Cicatrix. A scar upon the skin after the healing of a wound or ulcer. The 
cicatrix of bone is termed callus. 
Cilium (pi. cilia). Eyelash; applied, also, to a fine, hair-like process on cer- 
tain cells. 
Cinerea. Ash-colored. 
Circumflex. Bending around. 
Cirrhosis. Atrophy of normal tissue caused by new formation of connective 
tissue contracting and obliterating the vessels. 
Claustrum. Shut off; an enclosure; layer of gray matter between the island 
of Reil and the lenticular nucleus. 
Cleido. From relation with the clavicle. 
Clinoid. Bed-like. 
Coccus (pi. cocci). A berry; synonym for micrococcus or minute round 
organism. 
Coccygeal. Relating to the coccyx; lowest part of the spine. 
Coeliac. Relating to the abdominal cavity. 
Coeliac plexus. Solar plexus. 
Cogitative. To think; in mind; thought about; power of thinking. 
Cohesion. Molecular attraction between like molecules. 
Coition. A coming together. 
Collagen. The essential organic basis of connective tissue. 
Colloid. Like gum. Gelatinous and gummy (amorphous) substances do 
not pass readily.through septa, hence the name. (See Crystalloid.) 
Coma. Profound sleep with complete unconsciousness and slow, stertorous 
respiration. 
Comedo. Black-heads; face-worms. 
Comminuted. Broken into many pieces. 
Commissure. A juncture, or point of union. 
Concentric. Having a common center; thus, the bulb of the onion is a con- 
centric bulb, consisting of many layers one within the other. 
Concept. The mind’s own wrork, or its own power. 
Condyle. An articular eminence, round in one direction and flat in the 
other; a curved extension. 
Condyloid. Shape of a condyle. 
Condyloma. Soft, fleshy excrescence; a knot; an eminence. 
Conglomerate. Crowded together, as of many small glands forming a large 
gland. 
Conjunctiva. Joining together; mucous membrane covering the anterior 
portion of the eye-ball and the inner surface of the lids. 
Conniventes. Keeping; converging towards or approaching one another. 
Contaminated. Polluted; corrupt; tainted. 
Convolution (gyrus). Winding or folding, especially the outer part of the 
brain or intestine. 
Copula. Shackled, or bound. 
Corneous. Horny. 
Cornu. A horn. 
Coronary. Resembling a wreath or crown ; encircling. 
Coronoid. Processes of bone resembling a crow’s beak. 
Corpora pyramidalia. Pyramids of the medulla oblongata. GLOSSARY. 
285 
Corpus (pi. corpora). Body. 
Corpuscle. A very small body or mass of substance. 
Corrugated. Wrinkled. 
Cortex. Bark; outer layer of an organ. 
Costal. Relating to the ribs. 
Cotyledon. A circumscribed tuft of chorionic villi on the attached surface 
of the placenta. 
Cotyloid. Cup-form. 
Crepitant. Crackling. 
Crescendo. Increase. 
Cribrosa (Lat. cribrum, sieve). Having holes like a sieve. 
Cribriform. Sieve-form. 
Cricroid. Ring-form. 
Crista acustica. A crest or ridge in the ampullae of the semicircular canals 
of the ear. 
Crista basilaris. Slight elevation on the ligamentum spirale to which the 
lamina basilaris is attached. 
Cruciform. Like a cross. 
Crural. Pertaining to crus. 
Crus (pi. crura). A leg; resembling a leg. 
Crusta. A crust. 
Crystalline. Resembling or in part made up of crystals; matter in a solid 
state exhibiting a methodical arrangement of its molecules. 
Crystalline lens. A transparent structure just behind the iris in the eye- 
ball. 
Crystalloid. Resembling a crystallus; like crystals; matter that can be 
crystallized, as salts, acids, and alkalies; crystallizable substances easy 
to osmose, since they pass readily through septa, hence the name crys- 
talloid. (See Colloid.) 
Cupola. Vaulted roof of the apex of the cul-de-sac of the cochlea. 
Cupula ampullae, or C. terminalis. A soft, membrane-like material into 
'which project the nerve-hairs of the crista acustica of the internal ear. 
Curare. Same as woorara. 
Cutaneous. Pertaining to the skin. 
Cyst. A circumscribed membranous cavity occurring abnormally in the 
body, containing fluid, fat, or solid matter, but rarely pus. 
Cystic. Containing or composed of cysts ; pertaining to a cyst, urinary, or 
gall bladder. 
Cysticercus. The sexually immature larval form of taenia, or tapeworm ; 
tailed bladder worm; hydatid. 
D 
Deciduus, a, um. Falling off; membrane surrounding the embryo. 
Decussation. Crossing. 
Defecation. Evacuation of the bowels. 
Deferens. Bearing away; transporting. 
Deglutition. Swallowing. 
Dehiscence. A bursting or splitting open. 
Deliquesce. To become pasty and melt by absorption of water. 
Delirium. Irregular mental action, with illusion or hallucination. 
Dementia. Loss of reasoning power; incoherency of ideas; last stage of 
insanity. . : 
Dementia congenita. Idiocy. 286 
GLOSSARY. 
Dentatus, a, «m. Toothed. 
Denticulate. Having small teeth. 
Denuded. Laid bare; dissected off. 
Desquamation. Peeling or scaling off. 
Deterioration. Degenerating; impairing; growing worse. 
Diabetes. To pass through. 
Diabetes mellitus. A disease with sugar in the urine. 
Diagnose. The act of recognizing a disease by its symptoms; or, to dis- 
tinguish one disease from another. 
Dialysis. The process of separating mixed liquids or fluid substances by 
osmose; i. e., passage through an animal membrane. 
Diaphoretic. A remedy increasing secretion of sweat. 
Dirigent. Director; regulator; harmonious movements. 
Diuresis. Excessive discharge of urine. 
Diverticulum {pi. diverticula). A tube branching out of a longer one; a 
hollow appendage attached to and communicating with the intestinal tube. 
Dorsum (adj. dorsal). The back. 
Duct. A passage or canal. 
Durus, a, um. Hard. Dura mater. The external, dense, fibrous mem- 
brane surrounding the brain and spinal cord. 
Dynamia. Vital force. 
Dyscrasia. A bad constitution; morbid condition of the system, of the 
blood, or of a secondary nature as from a disease. 
Dysphasia. Difficult speech. 
E 
Earthy phosphates. Phosphate of ammonia, magnesia, and lime, found in 
urine. 
Economy. The aggregate of the laws which govern the organism; the en- 
tirety of an organic system. 
Efferent. A vessel transporting fluid, or a nerve conveying an impulse, 
away from an organ. 
Element. An original, essential part or principle of which a gas, fluid, or 
solid consists; i. e., their smallest natural division, which cannot be fur- 
ther divided without destroying the identity, such as hydrogen, sulphur, 
carbon, oxygen. 
Emetine. The active principle of ipecacuanha. 
Eminentia. A projection, process, or prominence. 
Emission. Discharge or throwing out. 
Emphysema. Air-swelling or tumor-like infiltration of air into areolar tissue. 
Empyema. Collection of pus in the pleural cavity. Sometimes applied to 
a similar condition in other parts. 
Emulsion. A preparation of an oleaginous or resinous substance with the 
addition of gum or the yelk of egg, held in suspension in a watery fluid. 
Encephalon. The brain and nervous matter within the cranial cavity. 
Endocardium. The inner lining of the heart-cavities, continuous with the 
endothelium of the inner coat of the great blood-vessels. 
Endogenous. Growing by multiplication or enlargement of the inner cells 
or tissues. 
Endomysium. The extension of the perimysium to and between the mus- 
cular fibres. 
Endoneurium. The minute web of connective tissue between the nerve- 
fibres within the nerve. GLOSSARY. 
287 
Enema. A rectal injection. 
Ensiform. Sword-shaped. 
Enteric. Pertaining to the intestine. 
Ephemera. A fever of short duration. 
Epigastric. Over the stomach; relating to the epigastrium; abdominal wall 
in front of the stomach. 
Epiglottis. A thin fibro-cartilage covered with mucous membrane at the 
upper part of the larynx, behind the base of the tongue and serving as a 
cover during deglutition to prevent food from entering the trachea. 
Epilepsy. A disease occurring by paroxysms, with convulsive movements 
of the voluntary muscles and loss of consciousness. 
Epithelioma. Carcinoma originating in epithelium. 
Erectile tissue. A tissue capable of turgescence and increase of size. 
Erythema (pi. erythemata). A hypersemic, red, circumscribed, non-elevated 
patch on the skin. 
Escharotic. A substance by which tissue may be destroyed, leaving a slough 
or crust. 
Etherization. Ether as an anaesthetic; influence of ether. 
Ethmoid. Perforated, as a sieve. 
Etiology. Doctrine of causes of disease. 
Euonymin. The principal active substance of euonymus. 
Evacuation. A discharge of matter; an emptying. 
Exanthemata. An infectious, febrile, eruptive disease. 
Excoriation. An abrasion, especially of the skin. 
Excrement. Matter naturally discharged from the body as useless. 
Excretion. Thrown off or cast out. 
Extravasation. Escape of fluid from its natural place to approximate 
tissues. 
F 
F. Fahrenheit scale to measure temperature. 
Facet. A separate articular surface. 
Faeces. Alimentary excrementitious matter. 
Faradization. Application or effect of the Faradic electric current. 
Fascia. A bandaged bundle; especially the connective sheath-appendage 
over muscles. 
Fasciculus (pi. fasciculi). Bundle of fibres. 
Fauces. The short passage between the back part of the mouth and the 
larynx and pharynx. 
Feces. See Faeces. 
Fertilization. Rendering or imparting the power to grow and develop; 
fruitful. 
Fibre. Thin; thread-like. 
Fibrillae. Minute fibres. 
Fibrinogen. The principal constituent of fibrin. 
Fibro. Prefix to words referring to fibrous tissue, either by composition, 
derivation, or resemblance. 
Filament. A minute thread or fibre. 
Fissure. A depression or fold inward; a cleft; narrow chasm between par- 
tially separated tissue. 
Fistula. An abnormal narrow canal with one or two end openings and ex- 
tending from one organ to another; incomplete or blind with only one 
opening, but complete with two. GLOSSARY. 
Flexure. A bend or curve. 
Foeticide. Killing of the foetus; criminal abortion. 
Foetus. Product of conception after three months—previously termed em- 
bryo. 
Follicle (Lat. follis, a small bag). A small tubular secreting sac. 
Folliculus (pi. folliculi). Follicle. 
Foramen (pi. foramina). An opening; a hole. 
Fornicatus. Arched or vaulted over. 
Fossa. A depression; a shallow, wide-mouthed cavity. 
Fovea. A small, shallow depression or fossa. 
Function. The action of an organ or set of organs. 
Fungus (pi. fungi). Mushroom; an order of cryptogamic plants. 
Funiculi. Bundles of nerve-fibres; small, cord-like structures. 
Fusiform. Spindle-shaped. 
G 
Ganglion (pi. ganglia). Small lumps or masses of special organs in the 
body, appearing under three forms: Those of the nervous system are 
always connected with nerve-fibres; the lymphatic (glands) with the 
lymphatic vessels; other ganglia, such as the thymus, thyroid (glands), 
and the suprarenal capsules. 
Gasserian ganglion (so named in honor of Dr. J. L. Gasser). This ganglion 
is on the trifacial nerve, and rests upon the apex of the petrous portion of 
the temporal bone, and is enclosed between two sheets of the dura mater. 
Gaster. Stomach; belonging to the belly or abdomen. 
Gastric. Relating to the stomach. 
Gastro. Prefix relating to the stomach. 
Gastro-intestinal. Relating to the stomach and intestines. 
Gemma. Bud; granule; granulation. 
Gemmation. Production by budding. On the parent organism buds grow, 
then separate into complete organisms. 
Genesis. Generation; production. 
Genio. Relating to the chin. 
Genital. Pertaining to generation or to the generative organs. 
Genito-urinary. Relating to the generative and urinary parts. 
Germ. A minute organic mass, capable of developing into a cell, organ, or 
organism. 
Germ-cell. The cell which contains the germ for reproduction of an organ- 
ism ; ovum-cell. 
Germination. Development of germs; vital development; first growth. 
Gestation. Bearing or carrying; pregnancy. 
Giant-cell. An abnormally large and active cell, originating from an abnor- 
mally increased number and size of nuclear divisions of protoplasm of the 
parent cell. 
Gland. An organ composed of cells, blood-vessels, nerves, and absorbents, 
with the function either to secrete fluid for use in the economy or to ex- 
crete as Avaste. 
Glandula (pi. glandulse). A small gland. 
Glenoid. A shallow cavity; socket- or pit-like. 
Globule. A small ball. 
Globulin. An albuminoid of blood-corpuscles. 
Globus. A ball. 
Glomerule. A small ball-like mass. GLOSSARY. 
289 
Glossa. Tongue. 
Glosso-pharyngeal. Relating to the tongue and pharynx. 
Glottis. Upper opening of the larynx at the posterior end of the tongue. 
Glucose. Grape-sugar; starch-sugar. 
Glucoside. An organic compound capable of the production of glucose. 
Gluten (gelo, congeal). The viscid, elastic, nitrogenous constituent of flour. 
Glutin. Vegetable albumen or gelatin. 
Glycocholic acid. A principal acid of bile. 
Glycosuria. Sugar in urine0 
Goblet cell. Goblet-shaped cell found among epithelial cells lining the mu- 
cous membrane, with a broad, open extremity. 
Goitre. Chronic enlargement of the thyroid gland. 
Gonorrhoea. A specific, contagious inflammation of the urethra or vagina, 
with a muco-purulent discharge. 
Graafian vesicles or follicles. Small sacs enclosing ova in the ovary. 
Gracilis. Slender. 
Granule. A small grain-like particle or body. 
Gravidus. Pregnant; impregnated. 
Graviditas. Pregnancy. 
Gustation. Tasting. 
Gynaecology. Science of diseases peculiar to women. 
Gyrus (pi. gyri). Convolution. 
Gyrus fornicatus. Convolution of the corpus callosum. 
H 
H. Symbol for hydrogen. 
Haematemesis. Vomiting blood. 
Haematuria. Blood in the urine. 
Haemoglobin. A crystallizable hsematin and globulin substance, originating 
in and coloring the red blood-corpuscles. 
Haemoptysis. Coughing blood from the lungs or air-passages. 
Hectic. Consumptive; pertaining to a wasting disease; fever of phthisis. 
Helicotrema. Snail-hole; orifice of communication at the summit of the 
cupola at the junction of the vestibular and tympanic passages of the cochlea. 
Helix. Bent; turned round; curled inward, as the external border of the 
outer ear. 
Helosis. Turned outward. 
Hemi. Half. 
Hemianaesthesia. Impairment or loss of sensation of one lateral half of the 
body. 
Hemiplegia. Paralysis of one lateral half of the body. 
Hemisphere. Half a globe; one lateral half of the brain. 
Hepar. Liver. 
Hepatic. Belonging to, pertaining to, or resembling the liver. 
Hepatization. Conversion into a substance resembling the liver; a state of 
the lungs when engorged with effused matter (as in pneumonia or pneu- 
monitis) i uo longer pervious to inhaled air. 
Hernia. Rupture. 
Hibernation (Lat. hibernare, to winter). The sleeping of certain animals 
during the entire cold period of the winter. 
Hilum, or hilus. The external depression where the nerves, ducts, and 
vessels enter and depart at certain organs, as on the kidneys. 290 
GLOSSARY. 
Hippocampus. Resembling in shape the downward, bended head and 
appended tail of a horse. 
Histology. Science of the minute anatomic constituents of organs and 
tissues. 
Homogeneous. Of the same kind, nature, or structure. 
Humor. Animal fluid; a secretion. 
Hyaline. Transparent; glass-like. 
Hyaloid. Relating to hyaline. 
Hybrid. Offspring of two animals or plants of a different species, and not 
capable of propagating its own species. . 
Hydatid. A tumor or vesicle consisting of a membrane filled with pellucid 
fluid. 
Hydra. A minute fresh-*water polyp. 
Hydration. Adding water. 
Hydrocarbon. A compound of hydrogen and carbon only. 
Hydrocephalus. Accumulation of water in the brain; serum within the 
ventricles or between the meninges of the brain; dropsy of the brain. 
Hydrogen. The lightest gas known — about times lighter than the 
atmosphere. In combination with oxygen it forms water. Hydrogen is an 
element of all organic bodies. 
Hydrophobia. An acute fatal disease resulting from the morbid poison of 
the saliva of a rabid animal, generally received from a bite. 
Hydrothorax. Accumulation of serous fluid in the pleural cavity. 
Hygroscopic. Able to absorb moisture. 
Hymen. Thin fold of mucous membrane at the entrance to the vagina in 
the virgin. 
Hypersemia. Increased quantity of blood in the capillary vessels of a part; 
congestion. 
Hyperaesthesia. Excessive sensibility. 
Hyperplasia. Excessive increase of elements of a part. 
Hypertrophy. Increase of a part from excessive nutrition, without change 
of the nature of the constituents. 
Hypochondriac region. The anterior sides of the abdominal cavity below 
the ribs to a transverse line from Poupart’s ligament. 
Hypodermatic. Under the skin. 
Hypogastric. Below the stomach; abdomen. 
Hypoglossal. Under the tongue. 
Hysteria. A neurosis occurring in paroxysms, with abnormally increased 
sensations; excessive susceptibility, with loss of voluntary power to 
restrain. 
♦ 
I 
Icterus. Jaundice. 
Idiopathic. Primary; not derived from nor depending on another. 
Ileo. Relating to the ileum. 
Ileo-caecal valve. A double fold of mucous membrane guarding the opening 
from the ileum into the large intestine. 
Ileum. Lower portion of small intestine, extending from the jejunum to the 
ileo-csecal valve. 
Ilia. Flanks. 
Iliac. Relating to the ilia. 
Ilium. Superior expanded portion of hip-bone. 
Imbibition. Sucking in or absorbing. GLOSSARY. 
291 
Inanition. Starvation from defective or scanty nourisment, or disorders in 
the nutritive processes. 
Incontinentia. Incontinence; inability to retain a natural evacuation. 
Indolent. Painless tumor of slow growth, or ulcer with no tendency to heal. 
Indurated. More solid than normal; hardened. 
Inertia. Loss of power to contract. 
Inflammation. Heat, redness, swelling, and pain in a part. 
Influenza. A special epidemic, catarrhal fever, with inflammation of gastric, 
oesophageal, and bronchial mucous and olfactory membranes, with nerv- 
ous pains and prostration. 
Infundibulum. Funnel-shaped. 
Infusoria. Minute ciliated organisms; micro-organisms; protozoa. 
Ingesta. Thrown in; contents of the alimentary canal, as food and drink. 
Ingravidation. Impregnation; pregnancy. 
Inguinal. Relating to the groin, or region where the thigh joins the body. 
Inhibition. Momentary diminishing or stopping of organic activity through 
nervous influence. 
Inorganic. Without organs; that which never had life. 
Inosculation. Union; communication; anastomosis. 
Insomnia. Sleeplessness. 
Interarticular. Between joints or articulations. 
Intercellular. Between cells. 
Intercostal. Between ribs. 
Interlobular. Between the lobules of a gland. 
Intermittent. Ceasing and returning at regular or uncertain periods, as the 
ague fever, and others. 
Interstitial. Between tissues; pertaining to connective tissue. 
Intertrigo. Chafing or excoriation between two integumental fleshy parts. 
Intravasation. Entrance of abnormal fluid into a perforated blood- or 
lymph-vessel. 
Intravascular. Within a blood-vessel. 
Introversion. Turned inward. 
Ischium. The lower part of the hip-bone. 
Isomeric. Having the same chemical formula, but possessing different phys- 
ical and chemical properties. 
Isthmus. The narrowed portion of an organ or passage connecting two 
organs or passages. 
J 
Jugular. Pertaining to the throat or jugular vein. 
Jugulum. Pertaining to the jugum, because fastened to the throat or ante- 
rior portion of the neck. 
Jugum. A yoke. 
' K 
Katabolism. Destructive process; tearing down tissues; degeneration. (See 
Anabolism and Metabolism.) 
Keloid. An irregular, reddish, firm, circumscribed, elevated connective- 
tissue growth on the skin. 
Kinetic. Effecting or involving motion. 
Kinetic energy. Energy which is essential to, or possessed by, a body or 
substance. (See Potential energy.) 292 
Kreatin. A white bitter substance produced during tissue waste of muscles, 
brain, and blood. 
Kreatinin. A normal nitrogenous constituent of urine, derived from kreatin. 
L 
Labium (pi. labia). Lip. 
Labyrinth. A structure of intricate winding passages; the internal ear 
formed by the vestibule, cochlea, and semicircular canals within the 
petrous portion of the temporal bone. 
Lac. Milk. 
Lacerated. Torn or mangled. 
Lachrymal. Pertaining to tears; the lachrymal artery, cells, duct, fossa, 
gland, groove, nerve, papilla, sac, tubercle, and veins. 
Lacteal. Milky; also, pertaining to the lacteal vessels. 
Lacteals. Those lymphatic vessels that collect the chyle in the intestines. 
Lactic. Pertaining to or derived from milk. 
Lactose. Milk-sugar. 
Lacuna. A small opening, pit, or depression, especially of a duct on the 
surface of the mucous membrane. 
Lamella, or Lamina. A thin sheet, layer, or plate. 
Lanugo. The soft, fine, rudimentary, woolly hair on the body. 
Laryngeal. Pertaining to the larynx. 
Larynx. The upper part of the trachea, or windpipe, containing the vocal 
chords. 
Laxator. Having a loosening or relaxing power, such as that produced by 
certain muscles. 
Lead-palsy. Paralysis of the extensor muscles of the forearm. 
Lens. See Crystalline Lens. 
Lesion. Injury; derangement; morbid change in structure or function of an 
organ or tissue. 
Lethalis. Mortal; deadly; deep stupor. 
Lethargy. Heavy, constant sleep without a conscious interval of waking; 
deep stupor. 
Leucin. White; a crystallizable, fatty product, from the decomposition of 
albuminous (nitrogenous) animal matter, often found in urine from disease 
of the liver, typhoid fever, small-pox, or muscular degeneration. 
Leucocytes. Colorless, small, cell-like, spherical and nucleated corpuscles 
of protoplasm, having the power of amoeboid movements, floating in lymph 
and blood, derived from the lymph-glands of the mesentery. 
Leucocythamplio. Increased number of leucocytes, accompanied by an 
abnormally decreased number of red blood-corpuscles. 
Leucomaines. Poisonous animal alkaloids developed in the living body by 
metabolic processes; constituents analogous to ptomaines. 
Leucorrhoea. White discharge, especially from the female genitals. 
Levator. Elevator; a muscle which raises the part to which it is attached. 
Life. Vitality; that enabling metabolism. 
Ligament. A white, strong, fibrous structure investing the joint, or uniting 
bones, or retaining an organ in its position. 
Ligate. To tie, bind, or constrict a part of an organ. 
Ligature. The appliance used in ligation, or binding. 
Limbic lobe. The convolutions above and on the side next to the corpus 
callosum. 
Limbus. An edge, or border. 
GLOSSARY. GLOSSARY, 
293 
Line. One-twelfth of an inch. 
Lingua. Tongue. 
Liquefaction. Becoming liquid. 
Lobule. A small lobe. 
Locus. Place; spot. 
Locus niger (substantia nigra). A layer of dark ganglionic cells in the 
crura cerebri, separating the crusta from the tegmentum. 
Logarithm. Referring to equality of force, strength, account, proportion, 
and number. 
Lucid. Bright; clear. 
Lucidus. Bright; light; glittering; sparkling. 
Lumbar. Pertaining to the loins. 
Lumbar region. Sides of the abdomen. 
Lunatic. An insane person with lucid intervals. 
Lunula (dim. of luna, moon). A small crescent. 
Luteus, a, um. Yellow. 
Lymph. The fluid within the lymphatic vessels. 
Lymphatic. Pertaining to lymph, lymph vessels, or glands. 
M 
M. Metre. 
MM. Millimetre. 
MMM. Micromillimetre. 
Macula. A spot or stain, without depression or elevation. 
Magnus, a, um. Great; large; powerful. 
Major (from magnus). Bigger; greater; more powerful. 
Malic acid. Acid of fruit. 
Malignant. Dangerous to life; cancerous. 
Malpighi. Relates to parts first described by Dr. Malpighi, an Italian anat- 
omist of the sixteenth century. 
Mamma (pi. mammae). Abreast; mammary gland. 
Mammillary. Nipple-like ; relating to mamma. 
Mania. Insane excitement; hallucination and delirium. 
Manubrium. Hilt, haft, or handle of anything. 
Mass. Any quantity of matter that is composed of molecules. 
Masseter. Chewing; assisting in chewing. 
Mastoid. Nipple-like projection. 
Mater. Mother. 
Matrix. A mother, womb, or place of origin of propagation of an animal, 
of tissue, or any substance, but never applicable to a woman or the womb 
of a woman. 
Matter. Anything that occupies space or takes up room, or that can exert 
or be acted on by force. Matter may exist in masses, molecules, or atoms, 
in either solid, liquid, or gaseous form. 
Maxilla. Jaw. 
Meatus. Canal. 
Medulla. Marrow; marrow-like. 
Meibomian glands. Small sebaceous glands on the margin of the eyelids, 
between the conjunctiva and the cartilage, first described by Dr. 
Meibomius. 
Meta. A prefix signifying beyond, over, after. 294 
GLOSSARY. 
Metabolism. Process of change, alteration, metamorphosis. It includes 
anabolism and katabolism. (See Anabolism and Katabolism.) 
Metamorphosis. Change of form, shape, function; transformation. 
Metaphysics. The science of things above and beyond physics; generally 
employed as synonymous with mental philosophy. 
Metre. A French measure, being 39.371 inches. 
Micrometer. A scale for minute measurement under the microscope. 
Micromillimetre. The millionth part (0.000001) of a millimetre. 
Micron. The one-thousandth part (0.001) of a millimetre. 
Micro-organism. A very minute organism. 
Micturition. The discharge of urine from the bladder. 
Millimetre. The one-thousandth part (0.001) of a metre. 
Mitral. Resembling a mitre—i. e., a bishop’s hat; name applied to the left 
auriculo-ventricular valve. 
Modiolus (dim. of modius, measure). The central pillar of the cochlea of 
the internal ear. 
Molecular attraction. See Cohesion and Adhesion. 
Molecule. A compound of atoms; the smallest compound of matter that 
can exist by itself; the physical unit of matter. 
Mollis. Soft; elastic; delicate. 
Monomania. Insanity confined to a single idea or subject. 
Morphology. The science of the forms and elementary constituents of tis- 
sues, organs, and organisms. 
Morsus (Lat. mordeo). A bite; grasp; sting. 
Mortification. Loss of vitality. When the part of a soft tissue mortified is 
recoverable, it is called gangrene; if totally destroyed, or dead, sphacelus. 
Mortification of bone when recoverable is called caries; when totally de- 
stroyed, necrosis. 
Mucin. The sticky, adhesive substance of mucus. 
Muco-purulent. Containing mucus and pus. 
Mucosin. Mucin. 
Mucous (Lat. mucosus). Of the nature of mucus; relating to mucous mem- 
brane. 
Mucus. A slimy secretion of the mucous membrane. 
Muscularis mucosa. A thin layer of unstriated muscle-fibres forming part 
of the mucous membrane. 
Musculin. Chief albuminoid constituent of muscle. 
Myo. Relating to muscle. 
Myolemma. A thin transparent sheet surrounding the muscular-fibre; sar- 
colemma. 
N 
N. Stands for nitrogen. 
Nabothian glands, or ova. Small, yellowish glands having follicles with 
no orifice, occasionally distended by their secretion, found between the 
folds of mucous membrane lining the cervix uteri. An anatomist named 
Naboth, finding them morbidly enlarged, mistook them for ova, hence their 
title. 
Narcotic. A substance producing lethargy or stupor. 
Necrosis. Death of bone. (See Mortification.) 
Nephritis. Inflammation of the kidney. 
Nerve-fibrillae. The minutest nerve-fibres within and between nervous- 
centres. Many fibrillae together appear like marrow. GLOSSARY. 
295 
Nervous. Relating to the nervous system, nervous centres, their stimulation, 
action, excitation, and disturbances. 
Nervus octavus. Relates to certain nerve-fibres contained in the nervus 
acusticus (auditory nerve), controlling muscular equilibrium of the head 
and body, but not connected with the sense of hearing. 
Neural. Relating to a nerve or nervous system. 
Nitrogen. A colorless, tasteless, inodorous, incombustible gas, 78 parts of 
which, with 22 of oxygen, constitutes atmospheric air. It is the generator 
of nitre, hence its name. 
Nucleolus (pi. nucleoli) The small nucleus within the nucleus of a cell. 
Nucleus (pi. nuclei). A central differentiated part of the cell; a nut, or ker- 
nel within a nut. 
o 
Occiput. The posterior inferior portion of the head. 
Oculomotor. Mover of the eye. 
Oculus. Eye. 
Odontoid. Tooth-like. 
(Edema. Swelling of tissue from an accumulation of serous fluid therein. 
(Esophagus. That portion of the alimentary canal extending from the 
pharynx to the stomach. 
Olfactory. Pertaining to the sense of smell. 
Omentum. A doubled membranous layer extending from the peritoneum to, 
and floating or laying over, a portion of the intestines. 
Ophthalmic. Relating to the eye. 
Os. Bone; also mouth, as os uteri, mouth of the womb. 
Oscillation. Vibration. 
Osseous. Bony, or resembling bone. 
Ossicle. A small bone. 
Ossification. Formation of bone. 
Otic. Relating to the ear. 
Oxidation. Conversion into an oxide, as of metals or other substances. 
Oxide. Neutral or basic compound of oxygen with a metalloid. 
Oxygen. A tasteless, colorless, inodorous gas, 22 parts of which, with 78 of 
nitrogen, constitutes atmospheric air. One part by volume of oxygen with 
two of hydrogen constitutes water. 
P 
Pabulum. Aliment; food. The term pabulum may properly be limited to 
the food of cells; i, e., the nutritious substances entering the organism be- 
come gradually more and more changed, and on arriving at the cells of 
tissues become protoplasm, or life matter. 
Palmaris. Referring to the palm of the hand. 
Papilla. Small conical eminence; nipple-shaped. 
Para. A prefix signifying beside, beyond, in addition. 
Parenchyma. The substance of glandular and other organs, composed of 
agglomerated globules united by cellular tissue, such as the lung, liver, 
spleen, and kidney. 
Parietal. Side wall of a cavity, especially the side of the head. 
Parotid. About or near the ear; relating to the salivary gland situated 
near the ear. 
Patellar reflex. Knee-jerk. 
Pathetic. Feeling; sympathy; name applied to the fourth pair of cranial 
nerves. 296 
GLOSSARY, 
Pathogenesis. Production of disease. 
Pathogenytes. Minute organisms which can grow in the living tissues, 
lymph, and in the blood; schizomycetes. 
Pathology. The doctrine of disease, its nature, and results. 
Pedicle. Stem; neck; stalk. 
Peduncle. Stalk or neck-like process by which an organ is attached. 
Pellucida. Clear; transparent. 
Pelvis. Basin ; large, irregular-shaped bone forming a conoidal cavity, open 
above and below, and enclosing the intestines, urinary and genital organs, 
its upper portion forming the hips. 
Peri. Prefix signifying around or about. 
Pericardium. A double membranous sac enclosing the heart. 
Perineum. The space at the inferior region of the trunk, between the ischi- 
atic tuberosities, anus, and genital organs, smaller in the female than in 
the male, triangular in shape, and divided into two equal parts, by the 
raphe. It is occasionally ruptured in labor. The part between the puden- 
dum and anus is called anterior perineum, to distinguish it from the part 
extending from the anus to the coccyx, called posterior perineum. Both 
the anterior and posterior are marked by the raphe (suture of the skin). 
Periosteum. Fibro-vascular membrane surrounding or lining the bones. 
Peripheral. Pertaining to the outer surface. 
Peristaltic. Khythmical vermicular motion of the intestine propelling its 
contents, termed peristalsis or peristaltic motion. 
Peritoneum. A strong extensive serous membrane surrounding all the vis- 
cera of the abdomen, lining the diaphragm, and through its orifices com- 
municating with the pleura above. Below it lines the abdominal cavity; 
anteriorly it is doubly reflected, forming the omentum, also the mesentery 
and ligaments of various organs; it passes over and surrounds the greater 
part of the bladder and uterus. 
Peritonitis. Inflammation of the peritoneum. 
Perversion. Turning or changing from good to bad; depravation; taking 
the wrong course. 
Petrous. Stone-like; referring to the hard, stone-like portion of the temporal 
bone in which is situated the organ of hearing. 
Peyer. A Swiss anatomist who first described Peyer’s glands. 
Phagedenic. Gangrenous. 
Pharyngeal. Belonging to the pharynx. 
Pharynx. Cavity between the posterior part of the tongue, nasal cavity, and 
oesophagus; the upper portion of the food channel. 
Phonation. Voice producing. 
Phosphate. A salt of phosphoric acid. 
Phrenic. Diaphragmatic; relating to the diaphragm. 
Phthisis. Tuberculosis; any pathological process causing continuous 
change and destruction of the lung or other tissue. 
Physical change. A change not altering the identity of the molecule (See 
chemical change). 
Pia Mater (tender mother). The vascular, delicate, plexiform membrane 
or immediate covering of the brain, penetrating its anfracuosities, and the 
continued envelopment of the spinal cord. 
Pigment. Coloring matter. 
Pilocarpine. The active principle of jaborandi; a powerful sudorific. 
Pilus (pi. pili). A hair. 
Pinna. Wing-like; broad part of the external ear. 
Pituitary. Slimy; phlegm-like; relating to the secretion of mucus. 
Planta. Sole of the foot. GLOSSARY. 
297 
Plastic. Submissive to formation or nutrition; yielding. 
Plethora. Excessive fulness of the blood-vessels. 
Pleura. The closed serous sac lining the internal surface of the thorax, 
divided by a septum (the mediastinum), each sac surrounding a lung. 
Plexus. A network. 
Pneumaticus. Windy; relating to air. 
Pneumogastric. Pertaining to the lungs and stomach. 
Pneumothorax. Accumulation of air in the cavity of the pleura. 
Polypus. A tumor on the mucous or serous membrane within a natural cav- 
ity, attached by one or more pedicles, occurring generally in the nose, 
vagina, uterus, or rectum. 
Pons. Bridge. 
Pons Varolii. A bridge-like structure of the brain described by Dr. 
Varolius. It is a thick, arched band lying across the brain-stem between 
the medulla oblongata and the crura cerebri. The nerve-fibres from the 
brain downward, and the spinal cord upward, pass through the pons. 
Portal {porta, door). Relating to the portal vein or portal system. 
Portio dura. Hard portion; the facial nerve. 
Portio mollis. Soft, tender portion; the auditory nerve. 
Potash. Vegetable alkali, obtained in an impure state by the incineration of 
a vegetable. 
Potential. Having latent power, which may or may not be used in future. 
Potential energy. Dormant energy, requiring favorable conditions for its 
manifestation; accidental energy. (See Kinetic energy.) 
Praecordia. Parts in front of the heart. 
Prima via. The alimentary canal from mouth to anus. 
Principle. The chief part; fundamental substance. 
Prism. A rectangular body having generally three rectangular plane faces, 
or sides, and two rectangular ends. 
Process. A prolongation or eminence connected with the principal part of 
an organ. 
Procidentia. Prolapse. 
Prognosis. The knowledge of the course and termination of a disease. 
Proliferation. Reproduction; cell-division; budding; gemmation. 
Prolific. Productive; abundant. 
Prominentia. Eminence; protuberance. 
Prophylactic. Preventive. 
Prostate. Standing before. 
Protoblast. Protoplasm. 
Protoplasm. Matter that is alive; the essential to the phenomena of all 
organic life; cell matter. 
Protozoa. Single-cell animalcula. 
Protuberance. Eminence; projection; pons Varolii. 
Proximate. Next in order; nearest to. 
Psychical. Relating to the soul or mind. 
Psychical blindness. Soul-blindness. 
Psychology. Doctrine of the human soul or mind. 
Ptoma. Corpse; carcass. 
Ptomaine. The principal acting substance in decayed or putrefied animal or 
vegetable tissue or matter. The ptomaine is to dead tissue or matter what 
the albuminoid (proteid) is to the living. 
Pubic. Relating to the pubes. 298 
GLOSSARY. 
Pubes. The bony arch above the external parts of the genital organs. 
Pudenda. External genital organs of the female. 
Pudic. Relating to the external genital organs and the parts immediately 
above. 
Puerperal. Relating to childbirth or a consequence thereof. 
Pulmonary. Relating to the lungs. 
Purulent. Containing or producing pus. 
Putrefaction. Decomposition of dead organic matter. 
Pyaemia. Fever due to pus absorbed into the blood. 
Q 
Quadrigeminus (from quatuor, four). Fourfold. The corpora quadrigemina 
are so called because they are like one corpus in nature and functions, but 
constitute four protuberances—two in each hemisphere. 
Quasi. As if; having the resemblance of something. 
K, 
Racemose. Clustered; in bunches. 
Rachis. Vertebral column; spine. 
Rachitis. Inflammation of the spine. Defective ossification with consequent 
distortion and bending of the bones; the rickets. 
Radiation. The transmission of energy through the medium of ether. 
Rale. Rattle; crepitation; rhonchus. 
Ramification. Branching. 
Rarefaction. Expansion. 
Receptaculum. A receptacle. 
Refraction. Turning or deviating from a direct course on entering a medium 
of different density. 
Region (physiologically). The tract; extent; or area. 
Regurgitation. Flowdngback; reflux. 
Renal. Relating to the kidneys. 
Resonance. Increase of sound by echo or vibrations of the walls of a cavity. 
Restiform. Cord or rope-shaped. 
Rete. Net; interlaced with fibres, vessels, or nerves. 
Retiform. Net-like. 
Retrahens. Drawing backward; name of a muscle on the back part of the 
external ear. 
Retroflexion. Bending backward, especially of the uterus. 
Retroversion. Turned backwards; term applied to that position of the 
uterus where the fundus is inclined toward the sacrum and the os toward 
the pubis. 
Rhachitis. See Rachitis. 
Rhomboid. Four-sided, with opposite angles equal, but with the front more 
exposed. 
Rhonchus. A rattling or wheezing sound. 
Rhythm. Regular and successive harmonious movements. 
Rickets. See Rachitis. 
Rigor. Sensation of cold, with involuntary shivering; chill. 
Rima. Fissure; cleft; furrow. 
Rima glottidis. The slit or opening between the vocal chords. 
Rolando. An anatomist of Piedmont, Italy (about 1775), who described the 
so-called fissure of Rolando. 
Ruga (pi. rugae). Fold or wrinkle. GLOSSARY. 
299 
s 
Saccharin. A white crystalline powder derived from coal tar, equal in sweet- 
ness to about 300 times its weight of cane-sugar; relates, also, to saccharum. 
Saccharum. Sugar. 
Saccule. A small sac. 
Sacrai. Pertaining to the sacrum. 
Sacrum. Wedge-shaped hone formed by the union of five vertebrae, attached 
to the last lumbar vertebrae and coccyx, and forming part of the pelvis. 
Sagittal. Resembling an arrow. 
Sanguis. The blood. 
Sanious. Thin, bloody matter of an ulcer. 
Saphena (saphenous). Superficial, such as the saphenous vein. 
Saponify. To convert into soap. 
Saprophytes. Minute organisms which can only grow in dead or decaying 
matter; schizomycetes. 
Sarcoid. Resembling flesh. 
Sarcolemma. The delicate, colorless sheath surrounding the muscle-fibre. 
Sarcoma. Fleshy tumor, with either spindle-shaped, round, or giant cells. 
Scala. Stairway; name given to the spiral passage-ways within the cochlea. 
Scaphoid. Boat-shaped. 
Scarf-skin. Epidermis. 
Schizomycetes. Parasitic schizophyta devoid of chlorophyll, including all 
minute organisms known as bacteria, microphytes, microbes, and other forms. 
Schizophyta. Common name of both groups of schizomycetes and algae. 
Sciatic. Relating to the ischium. 
Scirrhus. A firm, hard, carcinomatous tumor. 
Scrofula. Predisposition to hard, indolent, glandular tumors, often suppur- 
ating slowly and imperfectly, healing with difficulty, and usually occurring 
on the neck, behind the ears, and under the chin. 
Scurvy, or scorbutus. A morbid condition marked by inflamed gums, 
loosened teeth, haemorrhagic mucous surfaces, purpuric eruption, and de- 
pression, with general anaemia. 
Sebaceous. Pertaining to sebum. 
Sebum. Suet; a soft, white, fatty, oily substance secreted by sebaceous glands. 
Section. A cut; severance; division. 
Segmentation. Separation; formation or division into segments. 
Semilunar. Crescent-shaped; halfmoon-shaped. 
Senile. Pertaining to old age; feeble. 
Sepsis. Infection of putrefactive poison. 
Septicaemia. Disease aggravated by absorption of pus or putrid matter. 
Septum {pi. septa). Partition; separating wall. 
Serous. Pertaining to serum, or serous membrane. 
Serous membranes. Membranes lining closed cavities secreting serous fluids. 
Serrated. Toothed, like a saw. 
Serum. Watery portion of animal fluids. 
Sigmoid. Resembling the Greek letter “ S,” called sigma. 
Sinew. Tendon. 
Sinus. Cavity with narrow opening. 
Somnambulism. Walking or other actions while asleep, with consciousness 
suspended, but with the mind and other faculties active. 
Sopor. Deep, profound sleep. 300 
GLOSSARY. 
Soporific. Inducing sleep; hypnotic. 
Spasm. Sudden, irregular and involuntary contractions of muscles, due to 
reflex action of the spasm-centre in the medulla oblongata above the ala 
cinerea. 
Sphacelus. Gangrene of soft tissue, with complete death of the part. (See 
Mortification.) 
Sphenoid. Wedge-shaped. 
Sphincter. A muscle that surrounds and closes an orifice by contraction of 
its edges. 
Sphygmograph. An instrument for measuring or recording the rate, force, 
extent, and variations of the pulse. 
Sphygmus. Pulse. 
Spinous. Shape of a spine or thorn. 
Spirillum. Spiral schizomycetes. 
Splanchnic. Relating to the viscera. 
Splenic. Pertaining to the spleen. 
Spontaneous. Evolved by itself, without any assistance or any manifest 
cause. 
Squama (pi. squamae). Scale or thin scab. 
Squamous. Scaly. 
Stasis. Stagnation without morbid condition. 
Stenosis. Narrowing or constriction of an orifice or canal. 
Sterile. Not productive; barren. 
Sthenic. Strong; opposed to asthenic. 
Stimulus. That which excites or arouses energetic action. 
Stratum. Layer. 
Stria (pi. striae). A channel, groove, or furrow. 
Stroma. Tissues that constitute the groundwork of an organ. 
Struma. Scrofula. 
Strumous. Scrofulous. 
Stupor. Diminished activity of the intellectual faculties; insensibility; 
lethargy. 
Sty, styan, or stye. Hordeolum ; abscess of the eyelid. 
Styloid. Pointed ; shaped like a pin or peg. 
Subarachnoid. Beneath the arachnoid. 
Subclavian. Under the clavicle. 
Subcutaneous. Under the skin. 
Submucous. Part of the membrane just beneath the mucous portion. 
Sudor. Sweat; perspiration. 
Sudoriferous. See Sudoriparous. 
Sudoriparous. Producing or secreting perspiration. 
Suet. Sebum. 
Suffusion. Spreading or flowing over ; slightly diffused congestion. 
Sulcus (pi. sulci). A groove or furrow. 
Superciliary. Situated or being above the eyebrow. 
Suppuration. Formation of pus. 
Supra. Above. - 
Supraclavicular. Above the clavicle. 
Suprarenal. Above the kidney. 
Sylvian fissure. Deep, narrow groove or furrow (sulcus), parting the anterior 
and middle cerebral lobes. GLOSSARY. 
301 
Synchondrosis. Union or articulation of bones by intervening cartilage. 
Syncope. Fainting or swooning. 
Synovia. Fluid secreted by a synovial membrane. 
T 
Tabes. Wasting away; emaciation. 
Tabes dorsalis. Wasting of the posterior columns of the spinal cord, pro- 
ducing locomotor ataxia. 
Taenia. A tape; tapeworm. 
Taliacotian operation. Rhinoplasty; an operation performed by Dr. 
Taliacotius, an Italian surgeon, in 1575. 
Taurin. A colorless, crystallizable substance in bile. 
Temperament. The condition of the system with reference to either one of 
the four forms of disposition, or their combination, viz.: bilious, lymphatic, 
nervous, or sanguinous. 
Temporal. Relating or belonging to the temple. 
Tendinous. Pertaining to tendon. 
Tendon. Cord or sheet of condensed fibrous tissue connecting either muscle 
to muscle or to bone. 
Tenesmus. Frequent and painful straining and sense of desire for defecation 
or micturition, generally without discharge. 
Tentorium. A process of the dura mater across the back part of the cranial 
cavity separating the cerebellum from the cerebrum. 
Tessellated. Formed into squares; checkered. 
Tetanus. Spasms, with rigidity in paroxysms of tonic convulsions of the 
muscles of the jaw, spinal region, and limbs. 
Texture. The interweaving or arrangement of the tissues of an organ; 
tissue. 
Therma. Heat. 
Thoracic. Relating to the chest. 
Thorax. The breast chamber, formed by the ribs and costal cartilages, spinal 
column and sternum, between the neck and abdomen. 
Thrombus. A blood-clot formed during life in a vessel or tissue. 
Thymus, or thymus gland. An oblong, bilobate, soft, glandular body, very 
variable in size and color, large in the foetus and child, but small or not 
apparent in the adult, situated in the upper separation of the anterior 
mediastinum, containing a milky fluid. Its function is unknown. 
Thyra. A gate. 
Thyro. Prefix referring to the thyroid cartilage. 
Thyroid. Shield- or wedge-shaped. 
Topical. Local. 
Tormina. Twisting, griping pains in the bowels. 
Torpor. Numbness; debility; sluggishness. 
Toxical. Poisonous. 
Trachea. Fibro-cartilaginous air-tube extending from the larynx to the two 
bronchi; windpipe. 
Tractus. Tract. 
Transudation. The passage of fluid through tissues, which may collect 
(sweat-like) in small drops on the opposite surface, or evaporate from it; 
passage of blood through the vascular walls; oozing through a part. 
Trauma. A wround. 
Traumatic. Relating to a wound or injury. 
Trichina (pi. trichinse). A minute, hair-like worm. 302 
GLOSSARY. 
Trichina spiralis. The trichina found in muscles of animals, especially in 
swine. 
Tricuspid. Having three points. 
Trifacial. Term applied to the fifth pair of cranial nerves ; trigeminus. 
Trigeminus. Threefold; the fifth pair of cranial nerves. 
Trismus. Lockjaw; tetanus limited to the neck and jaw muscles. 
Trochlea. A pulley; a surface grooved like a pulley. 
Trochlear nerve. Fourth cranial nerve (patheticus); the motor nerve for 
the superior oblique muscle of the eye. 
Trophic. Relating to nutrition. 
Tubercle. Small, rounded eminence. 
Tumefaction. Act or process of swelling. 
Tumescence. Process of blowing up or swelling. 
Tumor. A circumscribed abnormal new formation of tissue. 
Tunica. A coat, or membranous envelope. 
Turgescence. Swelling. 
Tympanum. Cavity of the middle ear. 
Tyrotoxicon. Micro-organism; cheese poison. 
u 
Ulcer. A solution of continuity of soft parts, with loss of substance, produc- 
tion of granulation-tissue and secretion of pus. 
Umbilicus. The navel. 
Unciform. Hook-shaped. 
Uncinate. Hooked. 
Unicellular. Composed of only one cell. 
Unilateral. Relating to one side only. 
Unipolar. A centre-cell with but one prolongation. 
Uraemia. Accumulation of urea in the blood. 
Urate. Compound of uric acid with certain bases, such as salts of soda, 
potassa, ammonia, and lime. 
Ureter. A tube from 15 to 18 inches long, with the diameter of a goose-quill, 
conveying urine from the kidney to the bladder. 
Urethra. A membranous canal conveying urine from the bladder to the 
external orifice of discharge. 
Urinary. Pertaining to urine or the urinal organs. 
Uriniferous. Conveying urine. 
Uterine. Pertaining to the uterus. 
Uterus. Womb. 
Utricle. Small sac or cavity in the vestibule of the internal ear. 
Uvula. Conical organ at the soft, free edge of, and pendent from, the palate 
in the median line above the larynx. 
V 
Vagina. A five-inch tubular canal extending from the vulva to the uterus. 
Vagus. Wandering; the pneumogastric nerve. 
Valvula (pi. valvulse). A little valve. 
Varicose. Pertaining to varix. 
Varix. Permanent dilatation of a vein. 
Vas (pi. vasa). Vessel. 
Vascular. Pertaining to or containing vessels. 
Vaso-dilator centre. A centre in the medulla oblongata, the stimulation of 
which produces dilatation of the blood-vessels. GLOSSARY. 
303 
Vaso-inhibitory centre. See Vaso-dilator centre and Vaso-motor centre. 
Vaso-motor. Causing contractions of blood-vessels. 
Vaso-motor centre. A centre in the medulla oblongata giving origin to the 
vaso-motor nerve-fibres. 
Vein, vena, phlebs. Vessels conveying blood inward toward the heart. 
Vena (pi. vense). Vein. 
Venesection. Opening a vein; blood-letting. 
Venous. Relating to veins. 
Ventriculus. Ventricle; a cavity. 
Vermicular. Resembling a worm or its movement. 
Vermiform. Worm-like. 
Vesica. A bladder. 
Vesical. Pertaining to a bladder or cyst. 
Vesicle (Lat. vesicula). A small bladder, generally containing fluid. 
Vesico-vaginal. Relating to both bladder and vagina. 
Vestibule. Entrance. In German called Vorhof. 
Villous. Provided with villi. 
Villus (pi. villi). Velvet-like; fine, hair-like projections, especially of the 
intestinal mucous membrane. 
Virus. A substance, the result of a morbid process, capable of producing 
disease when inoculated; the active agent in the production of any infec- 
tious disease; a poison. 
Viscid. Sticky; adhesive. 
Viscus (pi. viscera). The organs contained in any of the three great cavities— 
cranial, thoracic, and abdominal, especially the two latter. 
Vis vitae. Force of life; the vital power and its effects. 
Vital. Relating to life. 
Vitellin. The principal proteid in the yelk of egg. 
Vitelline. Relating to the yelk of egg. 
Vitelline membrane. A very thin cell membrane of the ovum. 
Vitellus. Yelk (or yolk). 
Vitreous. Glassy; hyaline. 
Volar. Relating to the palm of the hand. 
Volition. The act of willing or choosing. 
w 
Woorara. Avery destructive poison of Guiana, which contains strychnia; 
curare; a South American arrow poison. 
X 
Xiphoid. Sword-shaped. 
Y 
Yellow elastic tissue. Certain connective tissue fibrillge, in thickness up to 
about 11 mmm, anastomosing with each other, found especially in the 
inner coat of arteries and lining of air-passages. 
z 
Zona. A girdle; envelope. 
Zone of Zinn. The anterior thickened portion of the hyaloid membrane at 
the margin of the crystalline lens. 
Zyme. Ferment. 
Zymogenic. Producing fermentation. 
Zymosis. Fermentation. INDEX. 
Abdomen 107 
expansion of in respiration... . 107 
reflex action of, 142, 277 
respiration in inflammation of, 107 
seat of lesion in paralysis of,.. 157 
Abducens nerve 135*, 170, 177 
Abortion, defined 277 
simulation of, 2o5, 266, 267 
suspicion of, 265 
Abscess, defined 277 
Absorbent system, defined 75 
Absorbents, functions of, 75 
Absorption, by lacteals 55 
by lymphatics 55 
cause of diminished, 42 
centre of, 135 
favored by alkalinity of juices 82 
Acarus lolliculorum 228 
Acetate, defined 277 
Acetate of lead, action on the liver 66 
Acetates (vegetable), changed in 
the blood 238 
Acid, abnormal secretion of, 38 
action on muscles 35 
effect on fibrous tissue 270 
carbolic, action on muscles.... 245 
carbonic, defined 283 
stimulus 91, 92 
vegetable nutrition 23 
citric, 31 
condition, effect on tissues.... 270 
diminished 31, 51 
fluids, number of 73 
gastric, neutralized in duode- 
num 50 
secretion of, 40 
hydrochloric, of gastric juice.31, 51 
increased 31, 38, 41, 51, 52 
lactic, change of in stomach..41, 51 
origin of, 32 
malic, 31 
of gastric juice 51 
of the body, a cause of,... .38, 248 
of vital tissue 51, 248 
phosphoric, in the brain 127 
production of, 38,114 
secretions 31, 38, 40, 41, 51, 73 
tannic, action on collagen 35 
effect on digestion 55 
tartaric, 31 
uric, origin of, 37 
Acid, vital tissue, 51, 248 
Accommodation of the eye.. .193, 277 
accomplished by, 194 
changes for distance 194 
limits of, 194 
nerve 174 
range of, 194 
time for, 194 
Aconitin, action on cells 65 
Achromatic 277 
'Acorn, starch of, 49 
Acoustic nerve (See Auditory Nerve). 
Action and reaction, effect of,.... 114 
Addison’s disease 240 
Adhesion, defined 277 
weakened by heat 119 
Adventitia 95 
Aether 196, 274 
Aetiology, defined 278 
Afferent nerve-fibres 72, 148 
After-birth 265* 
After-image 196, 278 
After-sensation 169, 196 
Ageusia 182 
Ague-iever, temperature of, 123 
Air, amount renewed m lungs... . 106 
amount required 107 
cells 40, 101 
change in respiration 108 
diffusion of, Ill 
expired 108 
insufficient oxygen of, 107 
sound of, 219 
vesicles 101 
Albumen 26 
amount in blood 27 
and its water, coagulation of,.. 27 
coagulation 27 
distinguished from albuminose 53 
distinguished from peptone.... 53 
in blood, property of, 27 
in the body, importance of, 116 
low respiratory excitant 113 
of blood, necessity of, 82 
origin of, 50 
of egg 26 
peptone 52 
pure, non-osmotic 78 
quantity in blood 81 
Albumin 278 
in urine 240 306 
INDEX 
Albuminoids, classified 54 
composition of, 54 
defined 54 
distinguished from albuminous 53 
origin of, 50, 54 
secretion of, 54 
similarity to alkaloid 54 
Album inose 26 
absorption of, 52, 53 
distinguished from albumen .. 53 
formation of, 50,52 
osmosis of 26 
Albuminous intermediate sub- 
stance of tissues 272 
matter, catalytic action of, 27 
coagulation of, 27 
defined 26 
distinction from albuminoid 53 
evaporation of moisture.. . 26 
importance of, 26, 82 
in the liver, change of, 63 
solidifies 26 
proximate principles, coagula- 
tion of, 27 
defined 26 
substances derived from, 26 
in urine 240 
Albuminuria 278 
Alcoholic beverage, effect on 
stomach 41 
on the iris 190 
injures mucous membrane. 52 
Alimentary canal 47* 
defined 278 
division of, 46 
epithelium of, 44 
mucous membrane of, 39, 55 
origin of, 260 
secretions of, 58 
Algse. 273, 278 
Alkali, action on muscles 35 
on the skin 231 
classified 279 
defined 279 
(strong), effect on blood cor- 
puscles 79, 81 
Alkaline carbonates 29 
absorption of, 55 
fluids 73 
phosphates 29 
salts, absorption of, 55 
derived from, 31 
excretion of, 31 
importance of, 31 
in urine increased 239, 249 
origin of, 31 
secretions 73 
sulphates 29 
Alkalinity, diminished 31 
increased 31 
Alkaloid 279 
Allantois 261, 279 
Aloes, action on the dog’s liver... 66 
Alveoli, membrane of, 40 
of the lungs 101, 104* 
epithelial cells 104 
number of, 104 
Alveolus of the lung, diameter of, 104* 
Amaurosis 279 
from indigestion 141 
Ammonia 279 
action on blood 79, 81 
on muscles 245 
as vegetable nourishment 23 
expired, 108 
use of in plants 23 
Ammonium chloride, action on 
dog’s intestine 66 
phosphate action on dog’s liver 66 
Amnion 261, 279 
Amoeba, reproduction of, 251 
Amoeboid movement 80, 81, 279 
Amplitude 279 
of sound 213 
Ampullseof the ear 202*, 208*, 209, 279 
Amyloid 33, 279 
Anabolism 115, 248, 279 
Anaemia 38, 42, 81, 106, 280 
Analgesia 146, 280 
Anasarca, a cause of, 78 
Anatomic element, defined 24 
function of, 24 
nerve-fibre supply of, 144 
Aneurism 280 
Angina pectoris 280 
Animalcule of water 269 
Animal, cold-blooded, respiration 
of, 110 
heat, production of, 114, 118 
instinct 128 
life, dependence on organs.... 23 
no nervous system in the lower, 93 
no reasoning faculty of, 128 
organic activity, vital principle 
of, 118 
respiration of, under water.... 116 
sensation in, 164 
vitality of, 109 
Ano-spinal centre 155 
Anterior chamber of the eyeball. 188* 
pyramid of the medulla 126* 
Anus, origin of the, 260 
spinal cord centre of the, 155 
Aorta 89*, 90*, 94 
Aortic plexus 161* 
valve 90* 
Aphasia 220, 280 
Apnoea 136 
Apomorphia 281 
action on pulmonary membrane 40 
Aponeurosis of muscles 241 
Apoplexy 281 
a cause of, 70 
pulse of, 96 INDEX. 
307 
Apoplexy, quickest relief of, 70 
when immediately fatal 136 
Apparatus, defined 24 
Appetite affected by reflex action. 141 
a natural guide for food 61 
unnatural, symptoms of, 84 
Aqueduct cochleans 206 
of Sylvius i 127* 
Aqueous humor of the eye 188* 
Arachnoid membrane 153* 282 
Area germinativa 260 
Areolar tissue 281 
Argentum nitras 281 
affecting the skin.. 225 
Argyria 225, 281 
Arrow-root 49 
Arteria centralis modioli 210 
Arterial blood, clots of, 86* 
constituents given off, 106 
red corpuscles of, 79 
temperature of, 119 
capillaries 94 
coat, tunica adventitia of, 95 
intima of, 94 
media of, 94 
contractility 95 
elasticity defined 95 
peristalsis 95 
pulsation, cause of, 95 
vessels, regulation of, 72 
walls, distinction of, 95 
Arterialization 281 
Arteries 88, 94 
anterior cerebral, 128* 
basilar, 128* 
blood-clot of ligated, 85, 86 
blood velocity in, 83 
bronchial, 104 
cerebral, 128* 
coronary, 90 
defined 88 
distinction in structure of,.... 94 
function of, 94 
hepatic, 62 
internal carotid, 127, 128* 
ligation of, 85, 86 
of the eye 192 
ovarian, 255 
permanently distended 95 
elongated 95 
posterior cerebral, 128* 
communicating, 128* 
property of, 95 
pulmonary, 90*, 102*, 104* 
renal, 234*, 235* 
spermatic, 255 
structure of, 94 
Sylvian, 128* 
umbilical, 265* 
uterine, 254 
vertebral, 127,128* 
walls of, 94 
Articulation (speech), defined 220 
muscles of, .. 217 
Artificial respiration 275 
Arytenoid cartilage 218* 
Asphyxia 107, 110, 136, 281 
to promote respiration in, 117 
Assimilation 281 
centre of, 135> 
Atax'a 231 
Ataxic aphasia 137, 221 
Atlas (vertebra) 151* 
Atom, defined 281 
energy of, 118 
Atomic theory, ether in accord- 
ance with, 274 
Atrophy, defined 281 
Atropia, action of, on pulmonary 
membrane 40 
action of, on the iris 125, 190 
Auditory area 216 
centre. 216 
external meatus 200,201* 
secretion of, 227 
ganglion 131 
internal meatus 180*, 201* 
nerve. 135*, 170, 180*, 201* 
terminals of, 215 
Auricle of the ear 200 
Auricles of the heart 90* 
Axilla, glands of, 227 
Axis-cylinder 144* 
process 138*, 282 
termination of, 145* 
Axis (vertebra) 151* 
Bacillus 273, 282 
Bacterium 273, 282 
Baer, vesicles of, 255 
Baptisin, action of, 66 
Basal ganglia 131 
defined 282 
Base, defined 238 
Basement membrane 43*, 282 
Basilar membrane 211*, 282 
Bass tones 219 
more difficult than crescendo 220 
Bed-sore 273 
Belladonna, action of, on pulmon- 
ary membrane 40 
Bell’s paralysis 179 
Bile, a cause of vomiting 55 
action of, 64, 65, 66 
on chyme- 50 
on pepsin 50 
on peptones 50 
an antiseptic 66 
bilirubin of, 34, 35, 64 
biliverdin of, 34, 36, 64 
color of, 64 
origin of, 62 
composition of, 64 
continuous secretions of, 72 308 
INDEX. 
Bile, decomposition of, 65 
defective, effect on blood 65 
diarrhoea from, 65 
duct, orifice of, 46, 68* 
ducts, function of, 64 
impaired, result of, 65 
emaciation from defect of, 65 
flow, cause of, 64 
haemoglobin in, secretion of,.. 106 
in blood, action of, on cells 65 
on the pulse... 65 
effect of, 122 
in stomach causes vomiting... 66 
material for, 62 
neutral in reaction 64 
obstruction, effect of, 65 
precipitating pepsin 55 
purgative action of, 65 
quantity secreted 64 
salts absorbed 65 
a natural tonic 65 
secretion 64 
apparatus 62 
depressed by lead acetate.. 66 
haemoglobin required in,... 106 
increased 55 
normal stimulus of, 67 
specific gravity of, 64 
Biliousness, a cause of, 65 
Bilirubin an albuminoid 34 
from haemoglobin 65, 261 
material for, 62 
origin of, 36, 70 
property of, 35, 64 
Biliverdin an albuminoid 34 
origin of, 36 
property of, 36, 64 
Bioplasm, defined 282 
Bipolar cell-processes 138* 
Black heads of the skin 229 
Bladder, (urinary), 239 
acidity, effect of, 156 
contraction, cause of, 124 
impulse of, 156 
inflammation, effect of,.... 156 
mucous membrane of,... .39, 41 
muscular fibres of, 246, 250 
nerve supply of, 156 
paralysis of, 155, 156 
spinal centre of, 155 
Blastoderm 260, 282 
Blindness from lesion of the cor- 
pora quadrigemina 131 
in hemiplegia 173 
Blind spot on the retina 196 
Blood 79 
albumen, amount of, 27, 81 
origin of, 52 
quantity of, 27, 81 
alkaline in reaction 73 
alkalinity of, 79, 82 
importance of, 82 
Blood, amount, variation of, 83 
arterial changed 105 
average velocity in arteries.... 83 
bile in, result of, 65 
carbonic acid gas absence in,. . 108 
certain matters retained for 
years in, 83 
changes in, 81, 100, 104, 105 
in the lungs, 104 
in coagulation 85 
circulation 88 
effect of disturbance of, 271 
of the body, time required.. 83 
retarded, effect on white 
corpuscles, 81 
velocity of, 83, 95 
where shortest 90 
clot 85, 86 
arterial, 86* 
composition of, 85 
coagulation of, during life, 85 
after death 85 
color of, 80 
composition of, 81, 85 
concentration in the heart, im- 
portance of, 83 
constituents, alteration of,.... 83 
corpuscles 79, 80* 
amount by weight of, 79 
broken up in spleen...62, 69, 84 
of lympli-glands 81, 84 
of the spleen 69, 84 
origin of, 82 
of white, 56, 81 
quantity in blood 81 
by volume 79 
red, 79, 80, 106 
anaemia of, 106 
color of, 35 
haemoglobin of 106 
oxygen attraction of,.... Ill 
white, .... 77, 80, 81, 84 
attraction of, 87 
derived from lymphatic 
glands 77, 81, 84 
number of, 81, 84 
size of, 81 
current, variation of, 82 
defective, result of, 83 
defined 79 
derangement, a cause of, 82 
deterioration prevented 83 
disintegration of 272 
effect of bile in, 122 
tibrin 85, 86 
coagulation of, 85 
disappearance in, 85 
importance of, 85 
origin of, 50, 85 
quantity of, 81 
fibrinogen of 50, 85 
flow in veins, cause of, 97 INDEX 
309 
Blood, gas interchanges of, 90 
globulin of, ..80, 85 
haemoglobin of, 35, 80, 106 
impurity, effect of, 83 
in capillaries 95 
in chlorosis 83 
in measles 82 
movement, rate of, 82, 83, 95 
of the lungs 103 
plasma 79, 82 
carbonic acid of, 108, 111 
constituents of, 82 
defined 82 
most necessary ingredient of, 82 
poison effect on different tissues 83 
retained, 83 
propulsion, force of, 95 
quantity, loss of in fatal haunor- 
rhage 83 
quantity of fat in, 81 
retention in lungs, time of,.... 104 
return to the heart, necessity of, 100 
salts, importance of, 82 
quantity of, 81 
serum, composition of, 85 
origin of, 82 
solids, quantity of, 81 
specific gravity of, 79 
sugar, quantity of, 66, 81 
syphilis retained in, 83 
temperature, high, effect of,... 119 
thrombus of, 86 
velocity, where greatest 95 
in the aorta 83 
capillaries 83, 95 
carotids 83, 95 
heart 83 
radial arteries 83 
veins 97 
venae cavse 83 
venous, changes of, 90, 105 
variation of, 100 
vessels fatty degeneration of,.. 273 
ligation of, 85, 86 
muscular fibres of, 246, 250 
origin of, 260 
regulation of, 72 
waste matters, quantity of,... 81 
water of, protected from evap- 
oration 223 
quantity of, 81 
when unfit for nutrition 83 
(white) disease 84 
Body activity, food required for,.. 110 
agitation of, 209 
chemical elements of, 24 
color of, 35, 222 
composition of, 24 
deranged from food 33 
dissolution of, 273 
elementary composition of,.24, 114 
equilibrium of, impaired 131 
Body equilibrium, nerve-fibres of, 180 
heat of, .114,115, 118 
loss of weight caused by urine, 
respiration, and perspi- 
ration 231 
of the epididymis 258* 
physical laws of 92 
subdivisions oi, 24 
weight reduced from want of 
bile salts 65 
Bones, constitutents of, 270 
flexibility of, 30 
gelatin and salts absorbed by,. 83 
incus, 202*, 203, 204 
lime phosphate of, 30 
malleus, 202*, 203, 204 
necrosis of, 270 
origin of, 260 
stapes, 202*, 203, 204 
Bowman’s capsules.... .234, 235*, 282 
Brain 125, 126*, 130* 
acid of, 127 
albuminous matter of, 127 
analyzed 127 
anterior lobe of, 126* 
blood supply of, 127 
cells, mental exertion effect on, 249 
centres 130* 
protected from over irritation 160 
subdivisions ol, 126* 
cerebellum, 126*, 132 
cerebrum, 126*, 127 
circulation increased, result of, 169 
commissure. 125*, 126 
convolutions 126*, 130* 
elements of, 127 
fat of, 127 
hem ispheres 125* 
impairment of, 127 
inflammation from defective ear 204 
insane, salts of, 127 
medulla oblongata. .126*, 134, 135* 
medullary substance, structure 
of, 144 
middle lobe of, 126* 
motor nerve-fibres, tract of,... 130 
nerve-fibres crossing 154 
posterior lobe of, 126* 
reparative process of , 249 
salts of, 127 
sensory nerve-fibres tract..130, 131 
subdivisions of, 125 
sulci of, 126, 128 
Bread, nutritious quality of, 32 
Breast 262 
Breathing, difficult, a cause of,.... 116 
Bright’s disease 121, 240 
(chronic) temperature in, 122 
normal temperature in,.. 121 
Broad ligament 252, 253* 
formation of,... 254 
Bronchi, formation of, 101, 102* 310 
INDEX. 
Bronchial secretion 40 
tubes 40, 282 
diameter of, 40, 101 
epithelium of, 43 
membrane of, 40 
Bronchioli 101, 104*, 282 
diameter of, 104 
Bronchitis, membrane affected in, 40 
Bruises, effect on cells 271 
Brunner’s glands 58*. 71. 76 
Bubo 78, 282 
Bui bus oculi 187 
Butter, formation of, 28 
Cachexia, defined 282 
Cadaver, rigidity of, 35 
Caecum 47* 
nerve-fibres of, 154 
Calabar bean, effect of, on the iris. 190 
Calamus scriptorius 136, 282 
Calculi, biliary, a cause of, 65 
pressure, result of,.. 65 
urinary, 37 
Calculus 282 
Calyces of the kidneys 234 
Callus, defined 282 
Calomel, action of, on a dog’s 
intestines 66 
Caloric 120 
Canalis reuniens 207, 282 
Canal (aqueduct) cochlearis 206 
of Nuck 254 
of Petit 188*, 189 
of Schlemm 188* 
of spinal cord (central),..152*, 153* 
semicircular 202*, 208*, 209 
Cancer, growth of, 271, 272 
roots of, 272 
symptoms of, 122 
Canine lamily, perspiratory glands 
in the, 108 
Capillaries 88, 97 
action of, 99, 111 
law of, 102 
blood velocity in, 83 
circulation in, 97, 98* 
centre of, 135 
importance of, 97 
defined... 97 
diameter of pulmonary, 104* 
in lungs, blood movement in,.. Ill 
in muscles 98 
muscular fibres of, 250 
networks of, 98,104 
of the skin 98 
peristalsis of, 98, 99, 111 
peristalsis in, centre of, 135 
plexuses of, 98 
variation of, 98 
pulmonary, 104* 
size of, 97, 98 
structure of, 95, 98 
Capsule, Bowman’s, 234, 235*, 282 
Glisson’s, 62 
suprarenal 239, 240 
Carbohydrate 27, 283 
Carbolic acid, action on muscles.. 245 
Carbon, amount, required in adult. 33 
defined 283 
dioxide. 101 
necessity of, for nutrition 33 
of food 27 
of sugar 27 
of vegetables 23 
Carbonate 283 
Carbonic acid, action on lungs.105, 136 
on muscles.... 107 
constituents of, 109, 115 
defined 283 
diamagnetic properties of,.. Ill 
during menstruation 116 
elements of, 108, 111 
elimination of, by lungs.108, 112 
by the skin 112 
by the urine 112 
excessive, effect of, 108 
excretion of, 113, 114 
formation of, 248 
formula of, 109 
from starch, sugar, and fat. 29 
gas(animal), when poisonous 111 
amount of, expired 108 
inspired 108 
(chemical), action of, on 
thirst Ill 
a diuretic Ill 
lessens heat Ill 
lessens irritability of 
the stomach.. . Ill 
slightly anti-emetic.. Ill 
elimination..82, 112, 113, 114 
escape of, from lungs 112 
experiments 110 
force of, 105 
formation of, 109 
imperfectly eliminated.. 105 
in blood, absence of,.108, 113 
in lungs 104 
origin of, 82 
secretion of. 82, 108 
weight of, 114 
importance of, 112, 113 
in blood-plasma Ill 
in child 116 
increase of, 113, 115 
in female 113, 116 
in lungs 104, 105, 112 
origin of, 108, 109 
in male 116 
in plants, absorption of,.. ..110 
in pregnancy, increased,.. . 113 
necessity of, 112, 115 
of cold-blooded animals.... 110 
of plants 23, 110 INDEX. 
311 
Carbonic acid, of the skin 112, 113 
of urine V2, 113 
origin of, 29, 113 
osmose of, 112 
repellent properties of, Ill 
stimulation 
..91, 92, 105, 108, 111, 112 
temperature, effect on, 112 
vegetable nutrition by, 23 
Carcass 273 
Carcinoma, 283 
Cardiac 90, 283 
contraction 91 
dilatation 91 
fatty degeneration 273 
ganglia 92 
movements 91 
muscular fibres 91 
orifice of the stomach 46 
action of, 41, 46 
plexus 92, 161* 
pulsation 91 
peristalsis 91, 92 
sounds 91 
ventricles 91 
Cardio-inhibitory centre 135 
Carotids, blood velocity in, 83 
Cartilage 270 
arytamoid, 218* 
basis of, 35 
cells of, 270 
change of, into bone 241 
chondrin of, 35 
cricoid, 218* 
ossification of, 241 
thyroid, 218* 
Caruncula mammillaris 171 
Casein, an albumoid 34 
coagulation of, 27, 34 
origin of, 50 
peptone of, 52 
secretion of, 50 
Castor oil, action on intestines,... 66 
Catalepsy 283 
Catalysis 27 
effect of, 78 
Catalytic transformation 27 
Catamenial period 266 
Catarrh, effect on hearing 205 
of bile-ducts, result of, 65 
Cathartics 66 
Caudate nucleus 130 
Cause and effect 98 
Cells..; 24, 25 
absorption by, 75 
activity, cause of, 92 
increased 113 
requirement of, 24 
connective tisuse, 270 
defined 25 
division of, 272 
'epithelial, 43*. 44*, 45* 
Cells, ciliated, 43* 
club-shaped, 43* 
columnar, 43* 
glandular, 45* 
squamous, 44* 
tessellated, 44* 
transitional, 45* 
function 25, 27, 42, 55, 72 
of intestinal, 75 
of secretory, 72 
variation of, , 25, 42 
gas secreting, 109 
giant, 272 
growth energy, primary origin 
of, 119 
life, increased activity of, 116 
life of, 271 
membrane, or cell-wall 25 
moisture effect on, 24 
multiplication of, 271 
nervous centre- 138 
nucleolus 43*, 138 
division of, 272 
reproduction of, 272 
nucleus 43*, 138 
division of, 272 
reproduction of, 272 
of connective tissues 270 
of the organ of Corti 211*, 212 
origin of, 271 
power of, 92, 93 
process of, in nervous centres,. 138 
reproduction of, 25, 271 
reproductive, 251 
secreting, 43, 44, 45, 54, 72 
structure of, 25 
wall, or membrane 25 
warmth, effect on, 24 
Centigrade, change of, into Fah- 
renheit degrees 121 
Centre, ano-spinal, 155 
auditory, 180*, 216 
cardio-inhibitory, 135 
cilio-spinal, 155, 156 
defined 283 
diabetic, 135 
for defecation 155, 157 
genito-spinal, 155 
most important, 92, 135, 136 
of absorption 135 
of assimilation 135 
of circulation 135 
in foetus 136 
of co-ordination 133 
of deglutition 135, 137 
of digestion 135 
of ejaculation 157 
of equilibrium 133 
of erection 157, 259 
of generative organs 155 
of gustation (See Centre of Taste), 
of hearing 169, 180*, 216 
stimulation. 312 
INDEX. 
Centre of inhibition of the heart. .135 
of iris. 131, 155, 189 
of mastication 137 
of micturition 156 
of motion 133 
of mucous membranes 135 
of olfaction... 171* 
of parturition i55,’ 156. 157 
of peristalsis j35 
of perspiration 135 
of pupil contractor.. .131, 189, 190 
. dilator 155, 156, 190 
°f respiration 135, 136 
reflexes by, 107,110,112 
ol salivary secretions 135 
of secretions 135 
°f sight .135, 169, *173* 
°f smell 169, 171*, 172 
of speech co-ordination... 135, 220 
of sphincter ani 154’ 155 
, vesicse ’.155 
°f taste 135, 169. 172, 181* 
of touch ' 169 
of urination i56* 157 
vaso-dilator, 135, 302 
motor, 135 
vesico-spmal, 155 
Cereals 32 
Cerebellum 126*, 135* 
function of, 133 
relation of, to equilibrium 209 
structure of, 132 
Cerebral arteries 127, 128 
convolution-centres not direct- 
ly connected with secret- 
ing or motor organs... 73, 94 
function of, 94 
motor nerve-fibres, tract of, 130 
quality, indication of, 128 
sensory nerve-fibres, tract of, 
130*, 132 
gray substance 128 
nerves (see Nerves). 
nervous centres 128 
surface, haemorrhage, effect of, 127 
white substance 124 
Cerebro-spinal nerve-fibres, decus- 
sation of,.. 157 
distribution of, 124 
path of, 132 
system, function of, 124, 162 
structure of, 124 
Cerebrum 126* 
blood-vessels of, 127 
convolutions of, i.26*, 127, 130* 
function of, 128, 129 
gray matter of,. ’ 128 
gyri of, 169 
importance of, 129 
location of, 127 
lobes of 126*, i28, 130* 
removed, effect of, 129 
Cerebrum,sensory centres of, 128, 169 
structure of, 127, 128 
sulci of, 126, 128 
white matter of, 128 
Cervical injury, danger of, 157 
sympathetic plexus 161 
Cervix uteri 252* 
Cheese 34 
when poisonous 274 
Chemical action, disintegration by 74 
reaction of, 92 
change, defined 283 
combinations, guide of, 248 
in the economy 116 
composition of the bodv 24 
elements,action in the economy 109 
number of, in the economy. 24 
of food, new compounds of, 50 
dissolution of, 50 
forces of organic life 94 
potential energy, conversion of, 120 
reaction in the economy .. 109 
Chemism and vitality 109 
Chest expansion in respiration... 107 
paralysis, seat of lesion in, 157 
tones 219 
wall, reflex of, in respiratory 
activity 112 
wound, care required of, 108 
Chestnuts, nutritious quality of,.. 49 
Chloroform, effect on iris. 190 
Chlorophyll 283 
of plants ’.’.23, 36 
Chlorosis 83, 283 
blood-corpuscles in, 83 
symptoms of, 84 
Cholera, effect on intestines 60 
Cholesterin 65 283 
Chondrin, an albuminoid .’ 34 
origin of, 50 
property of, 35, 54 
secretion of, 50 
Chorda tympani nerve .178, 283 
Chorea 283 
Chorion 261 
degeneration of, 266 
Choroid coat of the eye 187, 188* 
Chyle, absorption of, 56 
coagulation of, 85 
color of, 56, 75, 76 
constituents of, 56 76 
corpuscles of, !....’ 56 
defined, 55 
fibrin of, . . .7.56, 85 
formation of, 50, 56 
molecular basis of, 56* 76 
movement of, ’ 75 
vessels ] 75 
Chyme acted upon by bile 50 
changed into chyle 50, 56 
constituents of, 56 
transformed in the intestine.50, 56 INDEX. 
313 
Ciliary cells 42, 43* 
epithelium 42 
function of 42 
ligam ;nt 189 
motion 43 
muscles, 188* 
nerves 190 
processes 188*, 191 
Cilio-spinal centre 155, 156 
Circle of Willis 127, 128* 
Circulation 88 
accelerated during digestion... 141 
action of, on the heart 91 
blood, clots prevented 87 
capillary, 97, 98 
cause of, 91, 92, 95 
discovery of, 88 
duration of, 83 
effect of enfeebled,. 70, 96 
foetal, 265* 
function of, .... 80 
greater, 89 
lesser, 89 
portal, 96, 97 
pulmonary, 89, 90, 91, 96, 104 
reflex centre of, 135 
systemic, 89 
velocity of, 83, 95, 97 
venous, 97 
where shortest of the body.... 90 
Circulatory apparatus, structure of, 88 
centre of, 135 
action of, 110 
energy, primary origin of, 119 
impulse, sensory nerve of, 183 
Cirrhosis 284 
Citrates, absorption of, 55 
Claustrum 130. 284 
Clot of blood 85, 86 
Coagulable fluids 85 
Coagulation of blood 85 
absent or retarded 85 
conditions of, 85 
of chyle 85 
of lymph 85 
Cocoanut oil 29 
Cochlea 201*, 202, 206, 210* 
aqueduct of, 206 
cupola of, 210*, 211 
fluid of, 108 
lamina spiralis of, 210*, 211* 
natural size of, 210* 
nerve-fibres of, 180, 210* 
scalae of, 211* 
Coeliac axis 62 
nerve-plexus 67 
Coffee, effect of, in depression of 
spirits Ill 
Cogitative power 168 
Cohesion, defined 284 
weakened by heat 119 
Colchicum, action on dog’s liver.. 66 
Cold-blooded animals, exhalation 
by,.... 110 
tissue waste of. 110 
Cold diminishes excitability 140 
(ice) injurious to stomach 50 
Collagen, an albuminoid 34, 35 
origin of, 50 
property of, 35 
secretion of, 50 
Collapse, an indication of, 123 
Colloids 284 
Colocynth, an action of, 60 
Colon 47* 
nerve-fibres of, 154 
Color-blindness 197 
Daltonism 197 
eye, determination of, 197 
of bodies. 197 
of the economy 35 
vibrations of, 197 
Coloring matter, constituents of,.. 
26, 35, 36 
of the body 34, 35, 36 
origin of, 26 
property of, 35 
Colostrum, milk 263, 272 
Columnar epithelial cells 43* 
Coma, from haemorrhage 127 
Comedo of the skin 229 
Commissure fibrilla? 130* 
of spinal cord, anterior, 152* 
posterior, 152* 
optic, 135* 
Common sense 139, 163, 164, 165 
Conception,(corpus luteum), proof 
of, .. 257 
Concepts, manifestations of, 220 
Conclusions by experimenters on 
carbonic acid gas 110 
Concussion, effect on cells 271 
Cones of the eye 191* 
Congestion from plethoric condi- 
tion 81 
Coni vasculosi 258* 
Conjunctiva 193, 284 
Connective tissue 270 
mucous, 270 
non-elastic 270 
retiform 270 
white fibrous 270 
tendinous 270 
yellow elastic, 224, 303 
Conscience 165 
Consciousness, defined 166 
Constant current 247 
Constipation from insufficient bile. 65 
from jaundice 65 
Consumption, a cause of, 38 
from increased acidity 42 
Peyer’s glands affected in,.... 60 
Contagion 274 
Continued fever 274 314 
INDEX. 
Contraction, cardiac, 91 
muscular, 156. 246, 247 
of blood-vessels 95 
of pupil 189,190 
rhythmical 91 
Contunnii, liquor, 206 
Convulsions, a prevention of, 139 
by reflex 141 
from diabetes mellitus 67 
when fatal 158 
Co-ordination 140 
centre of, 133 
movements affected by, 140 
Corium of the skin 223*, 225 
variation of, 225 
Cornea, cause of milky appear- 
ance 187 
of opacity 187 
congestion of, 177 
defective nutrition of, 177 
result of injury to nerve of,... 177 
structure of, 187, 188* 
alteration of, 187 
ulceration of,.. 177 
Corona radiata 130 
Coronary circulation, the shortest 90 
vessels 90 
Corpora lutea, distinction of, 257 
quadrigemina 126*, 130* 
function of, 131 
structure of, 131 
striata, function of, 130 
haemorrhage of, effect of,... 127 
structure of, 130 
Corpus callosum 125*, 126 
dentatum of cerebellum 133 
luteum, true and false, 257 
of ovary 256*, 257 
striatum 126*, 130* 
Corpuscles of blood.79, 80*, 81, 82, 85 
Corrosion, effect on cells 271 
Corrosive sublimate, effect on dog’s 
liver 66 
Corti, membrane of, 211* 
organ of, 211*, 212 
Cortical substance of brain 128 
of kidneys 233 
Cotyledon 285 
Coughing, reflex impulses of,.... 184 
Courses, monthly, 266 
Cow’s milk... 28 
Cranial nerves 135*, 170 
Crepitus in lungs 106 
Crescendo, easier than bass-tone.. 220 
Cribriform plate of ethmoid bone.171* 
Crico-arytaenoid muscles... .217, 218* 
lateralis muscle 218* 
posticus muscle 218* 
Crico-thyroid muscle 218* 
Cricoid cartilage 102*, 218* 
capsular ligament of,218* 
Crista acustica 208*, 209, 285 
Crista basilaris .... 212, 285 
Crura cerebri 126, 130*. 135* 
structure of, 131 
Crushing, effect on cells. 271 
Crusta of cerebri. 130*, 132 
Crystalline lens 191 
Crystalloids 285 
Cupola of cochlea 210*, 211 
Cul-de-sac, Douglas’s, 254 
Curare, action of, 245 
Currents, velocity of nerve, 149 
Cutaneous perspiration 227 
effect on temperature, 123 
Cuticle 222, 223* 
of hair 230 
Cutis of the skin 223* 
vera 224 
Cysticercus 285 
Daltonism 197 
Dandruff 222 
Darkness, effect on iris, 190 
Dark spots before the eyes 196 
Deafness, certain causes of,. ..205, 206 
diagnosis of, 207 
of the soul (Seelentaubheit)... 216 
Decay and repair 23 
Decidua, defined 285 
origin of, 261 
refiexa 261 
serotina 261 
vera 261 
Defecation, centre for, 155, 157 
Degeneration, fatty, of heart 273 
Deglutition 137 
centre of, 135 
nerve of, 181, 186 
stimulus of, 181 
when choking, indication of,.. 137 
Delirium, defined 285 
in kidney disease 239 
Delivery, uterine secretion during, 253 
Dementia 285 
Derma of the skin 223*. 224 
thickness of, 225 
Dermis (skin) 223*, 224 
Desiccation, effect of, 271 
Detective, for diagnosis... 121 
Dextrin, dissolution of, 49 
production of, 49 
Dextrose, an amyloid 33, 49 
origin of, 49 
Diabetes 67, 286 
mellitus 67 
Diabetic centre 135 
Diagnosis 286 
temperature, importance of,... 121 
Dialysis 78, 286 
effect of, 78 
Diaphoretic 286 
Diaphragm 47* 
action by reflex 112 INDEX. 
315 
Diaphragm, action in respiration. 107 
nerve of, 103 
paralysis of, 103 
respiratory movements of, 107 
spasms, effect of, 103, 221 
Diarrhoea, a cause of, 60 
from cold or wet 141 
from increased acidity 42 
from increased quantity of bile. 65 
in phthisis , 60 
in typhoid fever 60 
Diastole of the heart 91 
Dicrotic pulse 96 
Diet, animal, 26, 27 
quality 33 
quantity 33 
vegetable 26, 27 
Diffusion of gases Ill, 112 
Digestion 48, 53 
acidity of, 41, 42 
centre of, 135 
defined 46 
difficult, 41, 42, 55 
during fever 60 
effect on temperature 119 
exercise, effect on, 50 
fermentation of, 55 
impaired, causes of,. .38, 50, 55, 56 
by fatigue 50 
by febrile disease 50 
by mental reflex 141 
by prolonged mental activity. 50 
from want of salts 247 
importance of, 50 
influenced by, 51 
intestinal, 57 
of food 48, 50 
rest, effect on, 50 
tannin, effect on, 55 
temperature of, 50 
Digestive apparatus 46 
fluids, sodium chloride stimu- 
lation of, 31 
juice, origin of, 51, 56 
secretion of, 49, 50 
stimulation of, 49 
organs 46 
process, effect on circulation.. 141 
Diphtheria 274 
Diphtheritic cocci 274 
Diplopia 175, 198 
from defect of nerves 178 
Direction of space 180 
Dirigents within the ear 207 
Discrimination in sensation 164 
Disease, a cause of, 38 
feigned, dia:nos:s of, 121 
impairs digestion 49 
Distance, estimation of, 194 
Dizziness 201, 209 
Doctrine of conservation of energy. 118 
Dog’s respiratory glands 108, 227 
Donder’s hypothesis of long eye- 
ball 198 
Dorsal vertebrae 151* 
Double conduction in nerves 148 
Double vision 198 
Douglas’s cul-de-sac (pouch) 254 
Dreams, a modification of imagi- 
nation 167 
Dropsy, a cause of, 78 
Drowning, respiration promoted.. 117 
recovery from, 275 
Duck’s respiration under water... 116 
Ductless glands. 240 
Ductus cochlearis.. 211* 
communis choledochus 57, 63*, 68* 
endolymphaticus 207 
Duodenum 46, 47*, 57, 63*, 68* 
Dura mater 153*, 286 
galvanic current, effect on, 127 
of spinal cord 153* 
Dyscrasia, a cause of, 82, 85 
defined 286 
Dysmenorrhoea 265 
Dyspepsia, treatment of, 51 
Dyspnoea, a cause of, 116 
Ear 200 
affected from eye disease 210 
auricle of, 200, 201* 
carbonate of lime in, 207 
cerumen of, 201, 227 
cochlea of,.... 201*, 202*, 206, 210* 
aqueduct of, 206 
cupola of, 210*, 211 
ductus of, 211* 
fluid of, 208 
lamina spiralis of,... .210*, 211* 
natural size of, 210* 
nerve-fibres of, 180, 210* 
sealse of, 211* 
concha of, 200 
conduction of sound in 207 
dirigents within the internal,.. 207 
disease, diagnosis of,... .• 207 
eminentia pyramidalis of, 205 
epithelium of, 42 
external 200, 201* 
function of, 200 
importance of, 200 
nerves of, 178 
injection, caution required in,. 209 
internal, 200, 201*, 206 
endolymph of, 208 
function of, 206 
semicircular canals of, 206. 208* 
structure of, 206 
vestibule of, 206 
labyrinth 2J6 
liquor Contunnii of, 206 
lobe of, 200 
meatus externus... .200, 201*, 202* 
internus 201*, 202*, 206 316 
INDEX. 
Ear, middle, 200, 201*, 202*, 203 
abscess of, 204 
acoustics of, 204 
air in, 206 
bones or ossicles of,.... 202* 
action of, 203 
excretory duct 206 
function of, 203 
muscles of, 202*, 205 
nerve of, 178 
pain from air in, 206 
perforated, danger to swimmers 204 
perilymph ,. 206 
pinna of, 200 
powder in, 207 
origin of, 260 
relation with eye 210 
saccule of, 207 
tympanum 203 
utricle of, 207 
vestibule of, 206 
wax 201, 227 
removal of, 209 
Earthy phosphates 286 
of urine 30 
held in solution 239 
increased 239 
Echo of sound 214 
Ectoblast 260 
Ectoderm 260 
Effect and its cause 98, 109 
Efferent nerve-fibres 72, 148 
Egg albumen, non-osmotic 78 
as nourishment 32 
composition of, 32 
Eighth pair cranial nerves 180 
origin of, 132 
Ejaculation, centre for, 157 
Elastic fibres 245, 246 
tissue 245, 246 
Elasticin, an albuminoid 34, 35 
origin of, 50 
property of, 35 
secretion of, 50 
Electric currents, action of, 149 
direct, and inverse 149 
effect on muscles 247 
most excitable stimulus of, 150 
Element , 286 
Elements of the body 24 
Eleventh pair of cranial nerves.. 184 
Emaciation, cause of, 33, 38, 66 
fat disappearing in, 28 
from want of bile salts 65 
Embolism 87 
Embryo, asphyxiation of, 136 
decay of, 266 
defined 259 
formation of, 259, 260 
Embryonic cell 260 
development 260 
Emmetropic eye 197 
Emetine, action on pulmonary 
membrane 40,41 
Eminentia pyramidalis of ear.. .. 205 
Emotion, effect of, on body 94 
co-operation, requirements of,. 137 
Emphysema 286 
Emulsion of fat 28, 65, 286 
Encephalon 125, 286 
End-bulbs 444, 147* 
End-plates 147* 
Endocardium . 286 
Endoderm 260 
Endolvmph of internal ear 207 
purified 212 
secretion of, 208 
Endomysium 241, 242*. 247, 286 
Endosmosis 29, 78, 82 
defined 78 
facilitated . . .* 82 
influenced bv sodium chloride.. 31 
regulation of, 31, 82 
suppressed... 77 
water required in, 29 
Endothelial linings, origin of, 260 
Endothelium 42 
distinctive characters of, 42 
Energy jqg 
and heat, relations of, 118 
conservation of, 118 
correlation of, 118 
kinetic, ug 
of food 119 
of muscular action, origin of,.. 249 
of nervous action, origin of,... 249 
potential, ng 
transmission through ether. . . 196 
use of, during sleep 33 
Entoderm 260 
Entozoa 269 
Ephemeral fever, temperature of, 123 
Epiblast 260 
Epidermis, appendages of . 223*, 229* 
changes in, 222 
deep layer of, 223* 
structure of, 222 
superficial layer of, 223* 
thickening of, 223 
Epididymis 258 
Epigastric plexus 161* 
Epiglottis 287 
action in speech. 217 
depression of, 218 
Epilepsy 139, I5g, 287 
Epithelial cells 43*, 44*, 45* 
ciliated, ’ 43* 
club-shaped, 43*, 44* 
columnar, 43* 
function of, 42 
glandular, 44, 45* 
of lungs 104 
of mucous membrane.. .42, 72* 
protection of, 43 INDEX. 
317 
Epithelial cells, squamous, 44* 
tessellated, : 44* 
transitional, 45* 
variety of, 42 
linings, origin of, 260 
Epithelioma 287 
Epithelium 42 
of villi 58* 
protection of, 43 
Equilibrium centre 133 
disturbed by reflex 141 
loss of, 209 
of body, impaired 131 
organ of, 209 
Erection, reflex act of, 259 
Ergot m large doses, effect of,.... 271 
Erythema 287 
Estimative faculty.. .139, 163, 165, 168 
defined 167 
Ether (fluid) spray, action on skin. 65 
Ether (gas) 274 
elasticity of, 196 
vibrations of, 197 
Etherization,nutrition affected by, 100 
Euonymin, action on dog’s liver.. 66 
Eustachian catheter 206 
tube 201*, 205 
membrane of, 40 
valve 90 
Exanthematous fevers 123 
Excitability, defined 140 
Excretion 74 
Excretory organs 74 
origin of 260 
Exercise, carbonic acid, result of, 248 
effect on digestion 50 
temperature of the body 119 
Exosmosis 29, 78 
influenced by sodium chloride. 31 
regulation of, 31 
water required in, 29 
Expansion, cause of, 118, 119 
Expectorants, action of, 40 
Experiments on carbonic acid.... 110 
Expiration, cause of, 101, 107 
impulse of, 112 
modus operandi of, 112 
stimulus of, 112 
Expired ammonia 108 
organic matter 108 
External auditory canal 200 
ear, (See Ear). 
sensation appreciation of 48,111,165 
senses 139, 163 
Extra-uterine foetation 262 
pregnancy 261 
Extremities, lesion of, in paralysis 157 
lower, nerves of, 155 
origin of, 260 
upper, nerves of, 155 
Eye 187 
accommodation of, 193 
Eye, accommodation, limits of,... 194 
range of, 194 
adaptation of, in vision 196 
affected from ear disease 210 
arteries of,.. 188, 192 
blood-vessels of, 190, 191* 
clear vision of, 194 
cones of, 191* 
conjunctiva 193 
constantly open, cause of, 193 
co-ordination of, 131 
diplopic, 175, 198 
emmetropic, 197 
hemeralopic, 199 
hypermetropic, or hyperopic,.. 197 
lashes, glands of, 227 
lens of, 191 
light, transmission of, 195 
long-sighted, 198 
movements of, 192 
mucous membrane, nerve of,.. 176 
muscles of, 188*, 192, 195 
myopic, 197 
cause of, 198 
near-sighted, 197 
nerves of, 188*, 190, 192 
normal, focus of, 197 
origin of, 260 
presbyopic,.’. 198 
reflection on, 193, 194 
refracting power of, 197, 298 
relation with ear 210 
rods and cones 191*, 192 
short-sighted, 197 
sight of objects 193 
sparks before the, 192 
Eyes, sense of darkness before the, 94 
simultaneous action in vision.. 173 
wide apart, benefit of, 194 
Eye-ball, anterior chamber of,.. .188* 
elongate 197, 198* 
injury to nerve, effect on,. . 177 
movements of, 174, 175, 192 
nerve-fibres for, 132 
muscles of, 174 
nutrition of 177 
sensory nerve of, 176 
short, flat, 197, 198* 
simultaneous movements of, 175 
structure of, 187 
Eye-lid, lower, nerve of, 176 
structure of, 193 
upper, drooping of, 174 
motion ot, 174 
nerve of, 174 
structure of, 192 
tarsus of, 193 
Face, expression, loss of, 179 
nerve of, 179 
muscles, nerves of, 178 
nerve of, 178 318 
INDEX. 
Face, neuralgia of, . 177 
paralysis, diagnosis of, 179 
skin, nerve-fibres of,..135, 175, 176 
Facial nerve 135*, 170, 178 
Fainting, cause of, 94 
Fallopian tubes, 252*, 253* 
cilne, vibration of, 254 
fimbriated extremities of,.. 254 
membrane of, 41 
muscular fibres of, 246 
False amnion 261 
corpus luteurn 257 
Falsetto voice 219 
Faradic current, powTer of, 150 
Fascia of muscles 241 
Fasting, emaciation, result of,.... 33 
on spleen 70 
Fat, absorption of, 29, 77, 82 
action on bowels 77 
a necessary ingredient of food. 28 
as a physic 77 
carbon of, 27 
cells 28 
decomposition of, 29 
derived from 26 
disappearance, effect of, 29 
elimination of, 29, 77 
emulsion of, 68, 76 
by bile.. 65, 66 
by pancreatic juice 68 
in chyle 76 
final disposition of, 29 
food produces heat 29 
globules broken up 273 
dissolved 273 
in blood, quantity of, 81 
not changed in stomach 29, 68 
of milk 28 
of tissues 28 
production of, in the body 28 
proximate principle of, 28 
tissue, capillaries in, 98 
use of, in the economy 29 
Fatty degeneration 272 
of the liver, a cause of, 65 
Fauces, nerve of, 181 
Feces, evacuation of, 154, 155 
odor of, 59 
water eliminated through, 30 
Fecundation of ovum 259 
reproduction by, 251 
Female generative organs 251, 252,253 
(See Ovary). 
Fenestra oval is 202*, 203, 207 
oscillations of, 203 
rotunda 202*, 203, 207 
Fermentation in stomach 55 
poison, effect of, 271 
Fertilization of ovum 259 
Fever, chronic, possible cause of,. 274 
effect on digestion 50 
temperature, symptom of, 123 
Fibres, muscular, 241, 243*, 244 
nerve, 72*, 143, 144*, 145* 
afferent,., 72, 148 
efferent, 72, 148 
motor, 72, 175, 244 
sensory 72, 175, 244 
vaso-constrictor, 72 
vaso-dilator, 72 
Fibrin, as such, not in blood.. .85, 108 
clot of, 80* 
coagulation of, 27, 55 
deficient, effect on blood-coagu- 
lation 85 
elements of blood,importance of, 85 
necessity of, 85, 86 
origin of, 50 
quantity of, 81, 85 
selection by the spleen. 70 
formation of, 85 
peptone of, 52 
thrombus of, 85, 86 
Fibrinogen 85, 287 
Fibrinose, absorption of, 54 
origin of, 50 
Fibrous tissues 270 
affected by acids 270 
of membrane 43 
Fifth pair cranial nerves 132, 175 
branches of, 176 
Fimbriated extremity of Fallopian 
tube 253*, 254 
function of, 262 
First pair cranial nerves 171 
Fission, reproduction by, 251 
Fissure, defined 287 
longitudinal, 125*, 126 
of Rolando 126 
parietal, 126 
Sylvian, 125*, 126 
Flower, fragrance of, 109 
Fluids, acid 73 
active principles of, 34 
alkaline, 73 
secretion of, 71 
Focal point 195, 198 
Foetus, circulation of, 265 
defined 259 
in utero, skin secretion of, 228 
Follicles 47, 48, 72* 
ducts of, 71 
of hair 229*. 
of intestine 58* 
of Lieberkiihn 58* 
function of, 76 
of stomach 49, 50 
secreting, 72*, 75 
walls of, 72* 
Food 46 
absorbed by the skin 55, 231 
absorption of, 55 
abstinence, effect on liver and 
spleen 70 INDEX. 
319 
Food, amount required 33 
change of, 52, 53 
chemical change before absorp- 
tion not necessary.. .55, 231 
classification of, 26 
cooked, necessity of, 49 
defined 110 
digestion of, 50 
energy.. 119 
transformation of, 249 
fat, necessity of,. .28, 29 
fluids, absorbed by skin 55, 231 
for vegetable growth 23 
important constituents of, 26 
mucous membrane affected by, 41 
oleaginous matter, necessity of, 27 
poison 274 
quantity determined 61 
relation to vitality 109 
solution of, 52 
sugar, necessity of, 27 
value dependent on, 33 
vegetable, as nourishment 32 
necessity of, 27 
when injurious 52 
when remaining undigested... 49 
Foramen of Monroe 127* 
Force, chemical, in a body 94 
in a molecule 112 
of attraction 112 
Fourth pair cranial nerves 174 
ventricle, structure of, 134 
Fovea centralis 196 
hemispherica 202* 
Freckles, due to, 223 
Frog’s respiration under water... 116 
Fundus of uterus 253* 
Fungus 288 
Gall-bladder 63*, 64 
a storehouse 64 
calculi in, 65 
discharge, cause of, 125, 141 
of contents 64, 141 
stimulus of, 112 
muscular fibres of, 246 
Gall-stone, a cause of, 65 
pressure, result of, 65 
Galvanic currents 149 
Gamboge, action on intestine 66 
Ganglion or ganglia 160, 288 
Andersh’s, 181 
auditory, 131 
basal, 131, 282 
cells of membrane 58* 
Gasserian.. 160, 161*, 175, 176*, 288 
injured, effect of, 177 
jugular, 181 
Meckel’s, 178 
of spinal nerves 161* 
ophthalmic, 161* 
function of, 190 
Ganglion or ganglia, otic (Ar- 
nold’s), 160, 161*, 210 
semilunar, 176 
spheno-palatine, 161* 
spinal, 153* 
submaxillary, 161* 
sympathetic, 125, 153*, 160 
as protectors 160 
Gangrene 271 
senilis 271 
Gas or gases, a fluid 102 
exchange in lungs 104, 111 
intermixture of, in lungs... Ill 
molecular motion of, 102 
osmosis of, 112 
pressure of, 112 
secretion of, 71 
separation of, Ill 
Gasserian ganglion. 160, 161*, 176, 288 
Gastric digestion 51 
conditions affecting, 51 
follicles 48 
function of, 40 
secretion of, 40, 48 
size of, 48 
juice, acid of, 51, 73 
abnormally increased 
secretion of,... 42 
deficient 51 
hydrochloric, 31 
lactic, 51 
neutralized 50 
origin of, 54 
actions of, 51,52 
amount secreted, 34 
arrested by, 55, 66 
artificial, 42 
no effect on starch 49 
pepsin of, 34, 51, 52 
neutralized 50 
origin of, 51 
secretion of, 48, 71 
membrane 48 
secreting follicles .47, 72* 
secretion, impaired, 50 
influence on, 50 
vein 63* 
Gastricus (See Stomach). 
Gastro-splenic omentum 69 
Gelatin 35, 83 
Gemmation, reproduction by,.... 251 
Generative organs, origin of, 260 
reflex centre of 155 
Genito-spinal reflex centre 155 
Genito-urinary organs, mucous 
membrane of, 41 
Germ or germinal 288 
area 260 
cell 251 
production of, 255 
mass 259*, 260 
membrane 259*, 260 320 
INDEX. 
Germ orgerminal spot..256*, 257, 259* 
vesicle 256*, 259* 
change of, 260 
movement of, 255 
Giant cells 272, 288 
Giddiness 209, 210 
Gland or glands 288 
Brunner’s, 58*, 71, 76 
buccal, 125 
cells of, 45* 
ceruminous, 227 
changes in, 45 
ductless, 71, 240 
ducts of 71 
epithelial cells of, 45* 
Horner’s, 227 
kidney, 71 
lachrymal, 71, 193 
nerve of, 176 
Lieberkiilm’s (See Follicles). 
liver, 71 
lymphatic, 78, 80 
mammary, 71, 74 
cells, function of, 83 
Meibomian, 193, 228 
Moll’s, 227 
Nabothian, 252, 294 
odoriferous, 227 
of axilla 227 
origin of, 260 
pancreas 71 
parotid, 125 
Beyer’s, 59 
pineal, 126* 
location of, 130*, 131 
pituitary 71 
prostate, hardened, result of,.. 239 
racemose, 71 
salivary, 71, 74, 125 
weight of, 62 
sebaceous, 71, 223*, 228, 229* 
secreting, .71, 75 
nerve-fibres of, 72*, 135 
nutrition of, 72, 100 
solid, 71 
solitary, 58, 59*, 71 
spleen 71 
submaxillary, 125 
sudorific (See Sudoriparous). 
sudoriparous 71, 223*, 227 
suprarenal (capsules),. 71, 240 
sweat (See Sudoriparous). 
testes 71 
thymus, 71, 301 
thyroid, 71 
Tyson’s, 22o 
Glisson’s capsule 62 
Globulin 80, 85, 288 
Globulose, absorption of, 54 
origin of, 50 
Globus major epididymis 258* 
minor epididymis 258* 
Glomerules of kidney. ..233. 234, 235* 
Glosso-pharyngeal nerve 135*, 170,181* 
Glottis, dilatation of, 218 
reflex respiratory activity of,. . 112 
Glucose, an amyloid 33 
change of, in the body 29 
different from protein 33 
formation of, ..27, 49 
from starch 34 
Glue from collagen 35 
Gluten 32 
Glycocholin, importance of, 66 
Glycogen absorption of, 76 
an amyloid 33 
different from protein 33 
of the liver 62, 64 
origin of, 66 
transformation of, 63, 64, 66 
Glycosuria 136 
Goblet epithelial cells 44* 
Graafian vesicles 256* 
bursting place 257 
number of, 255 
ripening of, 267 
Granular corpuscles 272 
Grape-sugar (See Glucose). 
Gravel, urinary, 37 
Graviditas in substantia uteri.... 262 
Gray hair 231 
Growth and decay 23 
Gums, upper jaw, nerve of, 176 
Gustatory centre.. .135, 169, 172, 181* 
fibres 181 
sensations 147, 182 
Gyri hippocampi 169 
Gyrus fornicatus 169, 171 
Hsematin 80 
origin of, 106 
Hsematuria 289 
Haemoglobin.. ..34, 35, 79, 80, 106, 289 
action of, 80 
amount in red blood-corpuscles 
35, 79 
an albuminoid 34, 80 
attraction of oxygen by,..35, 80,105 
change of, 80 
composition of 80, 106 
crystallizable 80 
decomposition of, 70, 106 
defective, result of, 106 
disintegrated, furnishes color- 
ing matter of bile..35, 36, 70 
formation of, 106 
given off in tissues 106 
globulin of, 80 
.hsematin of, 80 
importance of, in liver 106 
iron of, 35, 106 
origin of, 54, 80 
property of, 35, 80, 105 
proportion of, 35, 79, 106 INDEX. 
321 
Haemoptysis 289 
Haemorrhage, death from, 83 
fatal, quantity of blood lost... 83 
from nose and ear, danger of,.. 204 
from plethora 81 
internal, pulse symptom of,... 122 
on cerebral surface, result of,.. 127 
secondary, after ligation 85 
Hair 223*, 229* 
bulb of, 223*, 229* 
cells 229*, 230 
color 35 
cuticle of, 230 
erection of, 226, 230 
falling out 230 
follicles 228, 229*, 230 
gray, 231 
growth of 230 
stopped 230 
indestructible substance or,.... 35 
lanugo, form of, 230 
papilla of, 223*, 229* 
shedding, in animals 230 
silvery, 231 
Hands, tremor of, 133 
Head, involuntary movements of, 209 
equilibrium of, 209 
nerve-fibres of, 180 
neuralgia, nerve of, 177 
nodding of, 209 
note, or tone 219 
skin, nerve-fibres of, 135, 175 
Hearing 200 
affected by catarrh 205 
an external sense 163 
cerebral centre of, 169, 180* 
difficult, from ankylosis of ear 
bones 205 
dirigents of, 207 
how effected 215 
illusion of, 169 
impaired, from ear-wax 201 
improved by practice 216 
musical tones, limit of, 219 
nerve-fibres of, 135, 180 
sense-organ of, 212 
stimulation of, 146 
Heart 88, 89 
accelerated action of, 94, 110 
action, affected by terror 141 
inadequate on capillary cir- 
culation 99 
and lungs,harmonious action of, 110 
auricles of, 90* 
cavities of, 89, 90* 
diastole of 91 
examination of pulsation,...... 91 
greater circulation of, 89 
high temperature, effect on, 136 
impulse of, 135 
inhibition, centre of, 135 
lesser circulation of, 89 
Heart, liability to fatty degenera- 
tion " 273 
motion inverse to its power 96 
movements of, 91 
peristaltic 91 
stimulus for, 91 
muscular fibres of, 246 
arrangement of, 91, 246 
nerves of, 183 
nourishment of 90 
nutrition, rapidity of, 247 
orifices of, .... 89 
origin of, 260 
palpitation of, 84 
pulsation of 91 
regulation of, 92 
rest of, 91 
rhythm of, 91 
size of, 89 
sounds of, t 91 
systole of, 91 
valves of, 89 
ventricles of, 90* 
walls of, 90 
weight of, 89 
Heat, agitation by, 118, 119 
and energy 118 
caused by motion 119 
defined 118 
difference from temperature... 120 
diffusion of, 119 
effect of, on cell life 24 
on matter 118, 119 
energy, origin of, 119, 249 
equalization of, 119 
estimation of, 120, 121 
excitability increased by, 140 
expansion, power of 118 
from fatty food 29 
increased by muscular activity 249 
in molecular action 118 
molecular stimulus of, 113 
necessity of in organisms 24 
of plants 123 
production of, 114, 115, 118 
quantity eliminated in watery 
vapor 123 
retained in the body 29 
regulation of, 226 
source of, 118, 119 
variation in production 114, 115 
Hectic fever 274 
Helicotrema of cochlea 210*, 211 
Hemeralopia 199 
Hemiansesthesia 289 
from lesion of optic thalamus.. 131 
Hemiplegia 157, 289 
blindness in, 173 
from cerebral haemorrhage.... 127 
from indigestion 141 
from injury to corpora striata.. 130 
Henle’s layer in hair follicles... .229* 322 
INDEX. 
Henle’s looped tubes of kidneys.. 236 
Hensen’s disk of muscles 243 
Hepatic artery 62 
blood supply 63* 
blood-vessels 63 
cells, function of, 63 
circulation, result of increased, 67 
nervous plexus 67, 162 
remedies, absorption < f, 55 
stimulants,precaution required 66 
vein, function of, 64 
origin of, 63 
Hepatization 289 
Hernia 254 
Hernial sac, circulation of, 271 
Hibernation 289 
Hides, hardened with tannic acid 35 
Hilum of the kidney 233 
Hippocampus 171, 290 
Histology 290 
Horn, indestructible substance of, 35 
Horner’s glands 227 
Horror, effect on iris 190 
Human body (See Body). 
Human voice, limits of, 219 
Hunger, sensation of, 61 
Huxley’s layer of hair-follicles.. .229* 
Hyaloid membrane of eye. ..187, 188* 
Hybrid 258, 290 
Hydatids 253, 264, 266, 290 
Hydatidform moles 264 
Hydrocarbons 27, 290 
Hydrocephalus, pulse in, 96 
Hydrochloric acid of gastric juice 31 
origin of 41, 51 
sodium chloride in, 31 
when beneficial 51, 52 
when injurious 52 
Hydrogen 290 
in the body 24 
Hydrophobia 158 
convulsions of, 157 
Hymen, rupture of, 259 
Hyoscyamine, effect on iris...... 190 
Hyperaemia.. 290 
Hypersesthesia 290 
Hypergeusia 182 
Hypermetropia 197 
Hyperopic 197 
Hypertrophy 290 
Hypoblast 260 
Hypogastric plexus 161* 
Hypogeusia 182 
Hypoglossal nerve 135*, 170, 186 
fibres ot, 137, 186 
origin of, . .134, 135, 137, 186 
function of, 137, 186 
Hysteria 158, 290 
Ice, in stomach, impairs digestion 50 
Icterus 290 
Idiopathic 290 
i Ileo-coecal (ileo-colic) valve.46,47*, 290 
Ileum 46, 57, 290 
Ilium *. 290 
Illusion 169 
Image, after, 196 
defined 193 
formation of, 193 
Imagination 139, 163, 165, 167 
an internal sense 139 
defined 167 
representation by, 167 
Impregnation 259 
Impressions, duration of, 169 
from stimuli 139 
retained 169 
Impulse, transmission of, 148 
Inanition 291 
from increased acidity 42 
Indian corn, nutriment of 32 
Indians, olfactory sense of, 171 
Indigestion, causes of, 38, 42, 55 
effect on the eye 141 
from increased acidity 42 
treatment of, 52 
Infant, jaundice of, 65 
Infection 274 
Inferior maxillary nerve 176 
Inflammation, a cause of, 99 
defined 291 
effect on circulation 141 
Influenza 291 
Infusoria 269, 291 
reproduction of 251 
Ingesta 47, 291 
Inhibition of reflexes 156,162 
Inhibitory nerve impulses 72 
Inorganic bodies, aggregation by,. 23 
different from organic 23 
matter derived from, 26 
proximate principles 26, 29 
Insalivation of food 49 
Insanity, defined 129 
symptom of, 129 
Insectivorous plants 55 
Inspiration, centre of, 136 
muscles of, 107 
stimulus of, 110 
Inspired air, changes of, 108 
Instinct 139, 163, 167, 168 
in brute animals 128 
Integument 222 
Intellect and cerebral centre-cells 128 
operations of, 129 
Intelligence, degree of, 128 
Intercentral nerve-fibres 140* 
Intercostal muscles, action of, 107 
Intermittent lever 274 
Internal senses 163, 165 
organs of, 165 
varieties of, 139 
Intestinal contraction, cause of,.. 124 
digestion 56, 59 INDEX. 
323 
Intestinal fluids, alkaline reaction. 75 
effect on chyme 50 
secretion of, 71, 72 
cause of, 50 
favored by, 60 
secretion, abnormal, 60 
cause of, 60, 73 
change of, 60 
stimulus of, 73, 147 
worms 269 
Intestine or intestines, absorbents 
of, 57, 75 
absorption by, 56, 75 
blood supply of, 60 
cells, function of, 75 
glandulae solitarise of,.. .58, 59* 
large 46, 47*, 61 
membrane of, 61 
length of, . .46, 47, 57 
mucous membrane of, 
40, 57, 58*, 60 
muscular fibres of, 246 
nerve-fibres of, 154 
nerves of, 183 
normal congestion of, 60 
nourishment of, 60 
peristalsis of, 57, 162 
action of, 141 
cause of, 57, 60 
centre of, 135 
stimulus of, 147 
secretion by, 75 
small, 46, 47*, 57, 58* 
subdivisions of, 46 
sympathy with stomach and 
brain 141 
veins of, 63 
villi of, 57, 58* 
wall of, 58* 
muscular fibres of, 250 
structure of, 57, 58* 
Inunction of remedies 231 
Involuntary motor apparatus, ori- 
gin of, 260 
muscular fibres 249 
Iodide of potassium, absorption of, 55 
Ipecacuanha, action of, 40, 41 
on dog’s liver 66 
on pulmonary membrane.. 40 
Iridin, action on dog’s liver 66 ■ 
Iris 188* 189 
atropia, effect on 125 
blood-vessels of, 192 
calabar bean, effect on, 190 
chloroform, effect on, 190 
contraction of, 131, 174, 189, 190 
centre of, 190 
stimulants of, 190 
dilatation centre 155, 190 
stimulants for, 190 
functions of, 189, 190 
movements, cause of, 131 
Iris, muscles of, 190 
nerves of, 190 
structure of, 189 
Iron, driven off to tissues 106 
in blood, importance of... .106, 116 
in haemoglobin 35, 106, 116 
of food 35 
paramagnetic properties of,.... Ill 
Irritability HO' 
Irritation, effect of, 119* 
Island of Reil 130 
Isthmus of fauces, valve of, 46~ 
Jacob’s membrane 191*- 
Jalapa, action on the dog 66- 
Jaundice, a cause of, 65- 
temperature, a symptom. 122: 
in the infant, cause of, 65, 261 
Jejunum 46, 57 
Judgment, defined 129 
Katabolic process 115, 249, 291 
Katabolism 291 
effect of, 249 
of muscular tissue 248 
Katalepsy (See Catalepsy). 
Keloid 291 
Keratin 34, 35 
an albuminoid 34 
origin of, 50 
property of, 35 
secretion of, 50, 222 
Kidney or kidneys 233 
activity, stimulus of, 147 
as secreting glands 71 
blood supply of, 234 
calyces of, 234 
cortical substance of,.. 233, 234* 
disease of, 239 
temperature symptom of, 122 
excretion from blood by,235,236 
excretory duct of, 234 
function of, 236 
glomerules of, 233 
inflammation of, 240 
location of, 233 
lymphatics of, 234, 236 
medullary substance of,.... 233 
mucous membrane of, 41, 42 
nephritis 240 
nerve-fibres of, 234, 236 
origin of, 239 
pelvis, membrane of, 41 
pyramids of, 233 
secreting and excreting or- 
gans 74 
structure of, 233 
sympathy with stomach.... 141 
water elimination by, 30 
weight of, 233 
Kinetic energy 118, 291 
derivation of, 120 324 
INDEX. 
Koch’s bacillus, origin of, 274 
Krause’s membrane 243*, 244 
Kreatin 292 
Labyrinth of ear 206, 292 
Lachrymal duct, membrane of,. .. 40 
gland 71, 193 
nerve of, 176 
Lactates 31, 238 
absorption of, 55 
changed in blood 238 
Lacteals, absorption by, 55 
defined 75 
Lactic acid, change of, 41, 51 
Lactiferous ducts 263 
Lamina spiralis 210* 
Lanugo 230 
Lanula of the nail 232 
Larynx constrictor, during vocal- 
ization 218 
mucous membrane of, 42 
nerves of, 183, 185* 
Laughing, stimulation for, 103 
Law of conservation of energy... 118 
of Waller . 153 
Laws of nature, simplicity of,.... 98 
Laxatives, action of, 77 
fats 77 
salts 77 
Lead acetate, action on liver 66 
palsy 245, 292 
Lederhaut 224 
Legs paralyzed, seat of lesion in,. 157 
Lehman’s peptone 53 
Lens 188* 
absence, effect of, 195 
accommodation of, 193, 194 
affected by, 195 
artificial, 195 
changes, cause of, 195 
composition of, 191 
crystalline, of eye 188*, 191 
elasticity of, 194 
hardened, effect of, 199 
Lenticular nucleus 130 
Leucin 292 
Leucocytes 80*, 292 
origin of, 56 
Leucocythsemia 84 
Leucocythamplio 84 
Leucomaines 292 
Lieberkiihn, follicles of,.. ..58*, 71, 76 
Life, depends on, 23 
functions, change of, 269 
requirements for, 24 
most important centre of, 135 
secret of, 25 
Ligament or ligaments 292 
broad, 252, 253*, 254 
capsular, of cricoid cartilage .218* 
ciliary 189 
homogeneous material of,... 35 
Ligament or ligaments, ovarian,.. 
252, 253* 
round, 252, 253*, 254 
suspensory, of eye 188*, 189 
of spleen 69 
thyro-arytsenoid, superior..218* 
Light, appreciation of, 193 
bright, effect on iris 190 
efficient cause of, 196 
ether, vibrations of, 197 
focus of, 195 
impressions of 192 
itself not visible 193 
passage through eye 195 
nature of, unknown 196 
rays of, 196 
strong rays, effect on eye 189 
velocity of, 196 
Limbic lobe 169 
Limbs, tremor of, 133, 209 
Limbus luteus 191 
Lime carbonates 29, 30 
phosphates 29, 30 
held in solution 30 
of urine 30 
water, effect on muscles 245 
Lingual nerve 177 
Lip, lower, nerve of, 177 
upper, nerve of, 176 
Liquid or liquids, action on solids 119 
active principles of, 34 
diffusion of, 29 
Liquor Cotunnii 206 
sanguinis 79 
Scarpte 208 
Liver 62, 63* 
acini of, 62 
action increased 55 
of drugs on cells of, 66 
albuminous matter, change of, 63 
blood supply of, 62 
cells of, 62 
cirrhosis of, 284 
continual stimulus of, 67 
diabetes meliitus 67 
depressants, effect of, 67 
effect of functional derange- 
ment of, 67, 70 
enfeebled, 70 
enlarged, a cause of, 65 
fatty degeneration, a cause of,. 65 
function of, .62, 64 
gland 71, 74 
glycogen supplied to 62 
impaired, effect on spleen 70 
ligaments of, 62 
lobules of, 62 
location of, 62 
lymphatics of, 67 
nerve-fibres of, 67 
non-nitrogenous substances re- 
moved by, 64 INDEX. 
325 
Liver, obstruction of, 70 
protector of the body 64 
removes objectionable matter . 64 
secretory and excretory organ.64, 74 
spleen affected by, 70 
stimulants, absorpt'on of,..... 55 
stimulation, effect of, 67 
structure of, 62 
sugar 66 
disappearance of, 27 
formation 66 
origin of, 27, 63 
sympathy with stomach 141 
weight of, 62 
Living energy 120, 248, 249 
matter 249 
irritability of, 140 
Lobelia,action on pulmonary mem- 
brane 41 
Lobes of the brain 126* 
Lobuli testis 258* 
Locus niger 132 
Logarithm of stimuli 197, 293 
Long-sighted eye 197, 198* 
Lumbar plexus 162 
vertebrae 151* 
Luminous impressions 192 
Lunatic 293 
Lung or lungs 101, 102* 
action in unison with heart 110 
alveoli of, 104* 
blood of, 103 
capillaries, peristalsis of,... Ill 
of different functions. 104 
capillary network of, 104 
carbonic acid secretion 109 
stimulation of, 136 j 
crepitus in, 106 
elasticity of, 101 
expansion, cause of , 107 
expiratory stimulus, action 
of,.. Ill 
gas elimination of, Ill, 112 
gases, exchange in, 104* 
intermixed in, 104 
inspiratory stimulus, action 
of,. 111! 
liability to disease 39 
lobes of, 102 
lobules of, 101 
lymphatics of, 103, 104 
motion, peristalsis of, 91 
mucous membrane of, 40 
liability to disease..38, 39 
nerve and nerve-tibres.102, 183 
origin of, 260 
parenchyma of, 101 
nutrition of, 104 
respiratory activities of,... . 91 
secretory and excretory or-'an .74 
stimulus of, 105, 110 
structure of, 101, 102* 
Lung or lungs, time of blood circu- 
lation through, 104 
temperature high, effect on, 136 
water elimination ,..30, 108, 123 
weight of, 101 
wise arrangement of, 105 
Lymphatic or lymphatics 75 
absorption by, 55, 75, 78 
capillaries of, 77 
function of, 75, 78 
glands, enlargement of,... . 84 
of the liver 67 
of the lungs 103, 104 
origin of.. 260 
system 75 
vessels, structure of, 77 
valves of, 77 
Lymph 77 
absorption of, 75, 78 
alkaline reaction of, 73, 77 
coagulation of, 77 
composition of, 77 
corpuscles of, 56 
fibrin of, 77 
flow, in skin, facilitated 226 
glands 78 
product of 78 
size of, 78 
inflammatory, 81 
movement of, 77 
origin of, 77 
propelled 77 
quantity of, 77 
specific gravity of, 77 
Maculae Acusticae 207 
cribroste 207 
Macula lutea of retina 191, 196 
Magnesium carbonates 29 
phosphates .29, 30 
sulphate, action on intestine 66 
Malaria, effect on spleen 70 
Malarial disease, blood in, 84 
fever, temperature in, 123 
Malleus bone 202*, 204 
Malpighian bodies 233, 234, 235* 
Mammary glands 71, 74, 262, 263* 
alveoli of, 262 
blood supply of, 263 
cells, function of, 83 
colostrum secretion by, 272 
lobules of, 262 
lymphatics of, 263 
milk secretion by, 263* 
nerves of, 263 
Manganese sulphate, action on in- 
testine 66 
Massage, effect on muscles... .245, 247 
Masseter muscle, effect on masti- 
cation 177 
Mastication 49, 137 
by lateral motion 177 326 
INDEX. 
Mastication, centre of, 137 
muscles, nerve of, 176, 177, 186 
paralysis of, 177 
necessity of, 49 
stimulus for, 125 
Matrix 293 
of nail 232 
Matter 293 
change of, in body 74, 119 
heat, effect on, 118 
limited power of, 109 
Maturation of ovum 256* 
Measles, blood-corpuscles affected 
by, 82 
cocci of, 82 
temperature, symptom of, 122 
Meat, as nourishment 32 
food, a principal constituent of 26 
Meatus auditorius externus..200, 201* 
interims 201*, 202*, 206 
Mechanical motion, effect of, 119 
Meckel’s ganglion 178 
Mediastinum 89 
testis 258* 
Medulla 213 
Medulla oblongata.... 126*, 130*, 135 
functions of, 134, 135 
high temperature, effect on, 136 
injuries, effect of, 103 
location of 134 
most important centre of,92, 136 
reflex centres in, 92, 135 
structure of, 134 
Meibomian glands 193, 293 
Melanin 34, 35 
an albuminoid 34 
origin of, 50 
property of, 35 
Membrana basilaris 211*, 212 
decidua 252*, 261 
menstrualis 268 
granulosa 255 
limitans externa 191* 
interna 191* 
tympani 201, 202* 
accommodation of, 203 
function of, 202 
oscillation of, 203 
perforated, effect of, 2C4 
pressure on, 206 
Membrane 39 
degeneration of, 39 
genito-urinary, 41 
hyaloid, of eye 187 
mucous, 39 
muscular coat of. 58* 
of alimentary canal 39, 40, 55 
of bladder 39 
of the brain 286 
of bronchial tubes 40 
of Corti 211* 
vibrations of, 216 
Membrane of ear 39, 40 
of Eustachian tube 40 
of eye 39, 40 
of Fallopian tube 41 
of Krause 243*, 244 
of nose 39 
of oesophagus 40 
of Reissner 211 
of spinal cord 153* 
of stomach 39 
of uterus 39,'41, 252 
of vagina 41 
serous, 39 
submucous, 39 
Membranous labyrinth 206 
structure of, 208 
semicircular canals. 202*, 208*, 209 
Memory, defined 129 
Memory, sensitive, 139, 168 
Meninges 158 
Meningitis 158 
Menopause 269 
Menses, cessation of, increases car- 
bonic acid 113 
Menstruation 266 
absence of, 267, 268 
discharge by, 267 
fright, effect on, 141 
time of cessation 269 
Mental action and carbonic acid.. 115 
disintegration of tissue,. 74 
increases alkaline phos- 
phates in urine.... 239 
prolonged, impairs diges- 
tion 50 
reflex of, 94 
depression, effect on iris 190 
emotion, effect on body 94 
exertion, prolonged, effect of,.. 249 
excitation, perspiration caused 
.by,. 125 
functions impaired, effect of,.. 129 
Mercuric chloride, action on dog’s 
liver 66 
Mesoblast 260 
Mesoderm * 260 
Metabolic processes of cells and 
tissues 115 
Metabolism 248, 294 
Metamorphosis 294 
of tissues 78 
Metaphysics 168, 294 
Micrococcus 273 
Micro-organisms 294 
Micturition 156, 237 
centre for, 155. 237 
Middle ear, membrane of, 39, 40 
Milk, absorbed by sKin 231 
alkaline reaction of, 73 
as nutrition 32 
coagulation of, 27 
colostrum 263, 272 INDEX. 
327 
Milk, cow’s, 28 
curdling, cause of, 32, 34 
food, when contraindicated.... 34 
oil globules of, 28*, 263 
palmatin of, 28 
perfect combination as food... 32 
secretion of, 71, 263 
Milk-secreting cells.., 262, 263* 
lobes of, 263* 
Milk-sugar, origin of, 27 
Mind, defined 129 
respiratory action, modified by 
stimulus from, 110 
Miscarriage through fright 141 
Mitral valve 90 
Mixed nerves 170 
Modiolus of cochlea 210, 211* 
Moisture, effect on cell life 24 
in organisms, necessity of, 24 
Mo.ecular action, heat from 118 
basis of chyle 76 
motion, effect of, 119 
Mole, delivery of, 266 
not always a result of impreg- 
nation 265 
true and false 264, 266 
Moll’s glands 227 
Monomania 294 
Monro, foramen of, 127* 
Monthly illness 266 
Mormon temp e of Salt Lake City, 
sound reflection in 213 
Morphia, action on pulmonary 
membrane 40 
Morphology 294 
Morsus diaboli 254, 256 
Mortification 271, 294 
Motion, primary cause of, 92 
produces heat 119 
Motor aphasia 220 
centre of, 220 
nerve-fibrillse, tract of, 130* 
nerve-fibres 72, 147, 148 
currents, rapidity of,.... 149 
end plate 147, 244 
impulses, increase of,... 244 
varieties of, 72 
of muscles 244 
origin of, 170 
paths of, 130* 
nerves 170 
Motor-oculi nerve 170, 174* 
Mouth, glands of, 71, 74, 125 
origin of, 260 
Mucin 34 
Mucosin 34, 39, 43 
an abuminoid 34 
ni rogen of, 43 
origin of, 50 
property of, 34 
secretion of, 43 
Mucous connective tissue 270 
Mucous membrane 38, 71 
action of certain remedies 
on, 40, 41 
alveolar, 40 
apomorphine, action on,. .40, 41 
atropia, action on, 40 
congestion of, 40, 41 
degeneration of, 38, 39 
emetine, action on, 40, 41 
epithelium of, 42 
expectorants, action on, 40 
food action on, 40, 41 
formation of, 260 
genito-urinary 39, 41 
importance of, 38 
in bronchitis 40 
inflamed, effect of, 41 
intestinal, 40, 57, 58*, 60 
ipecacuanha, action on,..40, 41 
lobelia, action on, 41 
morphia, action on, 40 
muscular coat of, 58* 
nerve-fibres of, 135 
of alimentary canal.. .39, 40, 55 
of bladder 39, 41 
of bronchial tubes 40 
of Eustachian tubes 40 
of Fallopian tubes 41 
of kidneys 41, 42 
of lungs 40 
of nose 40 
of oesophagus 40 
of stomach 39 
of trachea 40 
of uterus 39, 41 
of vagina 41 
opium, action on, 40 
property of, 39 
respiratory, 39, 40 
structure of, 39, 58* 
submucous coat of, 58* 
Mucus 34, 39 
alkaline reaction of, 73 
constituents of, 39 
of vagina, acid reaction of, 73 
property of, 34, 39 
secretion of, 39, 42, 44, 71 
Mulatto, skin of, 240 
Multipolar cell-processes 138* 
Muscle or muscles 241 
acid, action on, 35 
production in, 248 
ammonia, action on, 245 
aponeurosis of, 241 
arrectores pilorum, 226 
arterial blood required by,. 247 
aryteeno-epigloitideus infe- 
rior, 217 
aryteeno-epiglottideus supe- 
rior, 217, 218 
arytaenoideus, 217, 218* 
attollens, 200 328 
INDEX, 
Muscle or muscles, attrahens, 200 
blood supply to, 242* 
carbolic acid, action on,.... 245 
cells, exhaustion in, 246 
ciliary, of eye 188* 
contraction of, 174 
color, oiigin of, 80 
contractde substance of,.... 35 
contractility of, 244, 246 
loss of, 246 
contraction of,. 248 
crieo-arytsenoideus lateralis 217 
posticus 217, 218* 
crico-thyroid, 217, 218* 
action of, 217 
decomposition of, 248 
elasticity of, 245 
endomysium of, 242* 
erector pili, 223*, 229*, 230 
excrementitious matter of,. 247 
extensor, tonicity of 245 
external rectus of eye 192 
nerve of, 177 
fascia of, 241 
fatigue of, 247 
fibres, size of, 244 
fibrin absorbed by, 83 
flexor, tonicity of, 245 
heat formation in, 249 
inferior cblique, of eye 174 
rectus, of eye 174, 192 
in repose, neutral reaction,.. 248 
intercostal, paralyzed, seat 
of lesion in, 157 
internal rectus, of eye..174, 192 
involuntary, contractile pow- 
er of, 124 
fibres of, 249 
katabolism of, 248, 249 
laxator tympani, 205 
levator ani, 154 
palpebra?, 174 
superioris, 192, 193 
lime water, effect on 245 
lingual, nerve of, 178 
lymphatics of, 242* 
massage, effect on, 245, 247 
masseter, 177 
mechanical perfection of,... 248 
metabolism of, 248, 294 
mixed, function of, 125 
myosin of, 246, 247 
nerve-fibres of, 242*, 244 
nerves of, 212*, 246, 250 
non-striped fibres..241,243*, 249 
nutrition of, 243, 247 
diminished 245 
by paralysis 247 
oblique, of eyeball 187 
oblique tensor, of skin 226 
of animal life 241 
of eyeball 174, 192 
Muscle or muscles, of head and face, 
nerve-fibres of, 135 
of heart... .88, 90, 246, 247, 273 
of mastication, nerve of, 175,177 
of middle ear 205 
of organic (vegetative) life. 241 
of skin 226 
of voice organs 218* 
orbicularis oculi 193 
origin of, 260 
oxygen required by, 247 
pabulum of, 247 
perimysium externum.241, 242* 
internum 241, 242* 
properties of, 244 
reaction of, 248 
recovery of, 245. 247, 248 
recti, of eyeball 187, 188* 
relation to tendons 242 
required action in speech... 217 
respiratory action, by reflex 112 
rest required for, 247 
retrahens, 200 
rhythmical contraction of,. 91 
sensitiveness of, 244, 246 
sphincter ani, 154 
centre for, 155 
sphincter vesicse, 156 
centre for, 155 
stapedius, 202*, 205 
sterno-mastoid, nerve of,... 185 
stimulants for, 247 
strengthened by activity. .. 244 
by massage 245. 247 
strength of, dependent on 
number of fibres 248 
striae of, 243*, 244 
structure of striated,. .241, 243* 
superficial, best supplied 
with nerves 244 
superior oblique, of eye. ... 174 
rectus, of eye 174, 192 
temporal, 177 
tensor tympani, 202*, 205 
tetanus, effect on, 157 
thyro-arytaenoideus.. .217, 218* 
thyro-epiglottideus, 217 
trapezius, nerve of, 185 
unstriped fibres, size of, 249 
vascularity of, 247 
voluntary, 246 
impulse to, 130 
waste removed from, 248 
weight per cent of the body 241 
work of, 248 
Muscular action 248 
activity, heat production by,.. 249 
increases carbonic acid. 113, 246 
nutrition diminished during, 247 
primary origin of, 110 
vessels dilated during, 246 
alternate contractions 246 INDEX. 
329 
Muscular atrophy from want of 
salts 247 
coat of mucous membrane.... 58* 
of secreting organs 72* 
contractility, after death 248 
loss of, 246, 247 
principal element for, 35 
contracting substance 35, 246 
contraction 246 
affected by temperature 246 
diminished 246 
stimulus of, 246 
wave-traveling 246 
co-ordination, centre for, 133 
depression 247 
elasticity 244, 245 
energy, origin of, 249 
excitability 245 
fasciculi 241, 242* 
fibre or fibres 242*, 243* 
cells of, 242* 
change of, 241 
disks of, 243* 
Krause’s membrane of, 
243*, 244 
impulses for, 244 
of bladder 250 
of blood-vessels, 250 
of capillaries 250 
of intestines 250 
of skin 250 
of uterus 250, 252* 
sarcolemma of,242*, 243, 244 
size of, 244 
stimulus of, 250 
structure of, 244 
terminal plate of,. .147*, 244 
irritability 244 
diminished 148 
distinct from nervous, 148 
restored 148 
motor nerves from cerebro-spi- 
nal system 246 
paralysis 149 
relaxation 246 
stimulation, direct, 246 
indirect, 246 
striped fibres, contraction of,.. 246 
system, origin ot, 260 
tissue 241 
as food 26 
chief constituents of,. 26 
capillaries of, 98 
color, origin of, 80 
depression of, 247 
excitability 245 
tonicity 244, 245 
twitching from galvanization of 
dura mater 127 
weakness, a cause of, 35 
Musculin in food, importance of,. 26 
Musical sounds, difference in,.... 213 
Musical sounds, vibrations, limit. 213 
tones, character of, 213 
limit of hearing, 219 
vibrations required 216 
Myolemma 294 
Myopia 197 
Myosin 34, 35 
an albuminoid 34 
coagulation of, 35 
contractile substance 246 
diminished, effect of, 247 
origin of, 50, 54 
property of, 35 
secretion of 50 
Naboth, glandular follicles of, 252, 253 
ovula of, 253 
Nabothian glands 294 
Nail-root. 232 
Nail, structure of, 231, 232 
Nasal mucous membrane, ntrvre 
of,.. 175, 176 
thickening of,... 176 
Nature, no absolute rest in, 119 
simplicity of its actions 52 
of its laws 92, 93 
Nausea of pregnancy 141, 264 
reflex action of, 182 
Nauseous drugs, swallowed pleas- 
antly 183 
Near-sighted 197 
Neck of uterus 252*, 253* 
Necrosis 294 
of bone 270 
Nephritis 240, 294 
Nerve or nerves, 143, 170 
abducens,. ..135*, 170, 177, 178* 
function of 177 
liability to paralysis.... 178 
origin of, 177 
and its fibres 144* 
auditory, 
135*, 170, 180*, 201*, 208* 
function of, 180, 208 
origin of, 132, 180 
terminals of, 215 
auricular branch, 183 
cardiac cervical branch 183 
thoracic branch 183 
chorda tympani 178, 283 
cranial 135*, 170 
currents, rapidity of, 149 
defined 143 
descendens noth branch,... 186 
diaphragmatic, 103 
double conduction in, 148 
eighth pair cranial, (See 
Nerve Auditory), 
eleventh pair cranial, (See 
Nerve fcpinal Accessory). 
excitability of,. 144, 148 
facial, 135*, 170, 178, 179* 330 
INDEX, 
Nerve or nerves, facial, function of, 178 
origin of, 178 
fat absorbed by, 83 
fatigue of, 148 
fatty degeneration of, 273 
fibre orhbres.143,144*, 145*, 147 
afferent, 72, 148 
axis-cylinder of, 
143, 144*, 145* 
disintegration of,.. 153 
branches of, 145* 
change of, 144 
classification of,.. .72, 143 
constant current,effect 
of, 150 
constriction of,..144, 145* 
degeneration of, 153 
diameter of, 143 
division of 149 
efferent 72, 148 
electrical stimuli, effect 
on, 149 
function of, 148 
irritability of, 148 
length increases the 
power of, 244 
medullated, 143 
medullary layer of,.. 
143, 144*, 153 
motor impulses, vari- 
eties of, 72 
motor, paths of 132 
non-medullated, 143 
nutrition of, 153 
of liver 67 
of lungs 102, 183 
of muscles 244 
of pancreas 69 
of secreting organs... 135 
passages 73 
peripheral termina- 
tions of, 144 
plexus, deep cardiac,161* 
plexus, semilunar,.. .161* 
plexus, superficial car- 
diac, 161* 
plexuses of, 144 
recovery of, 148, 149 
sensory, tract of,.132, 160 
separation of, 144* 
sheath of, .143, 144*, 145* 
structure of, 143 
termination of, 144 
vaso-dilator 72 
vaso-motor 72 
fibrillse 140*, 144, 294 
fifth pair cranial (See Nerve 
Trigeminus). 
first pair cranial (See Nerve 
Olfactory). 
fourth pair cranial (See 
Nerve Trochlearis). 
Nerve or nerves, frontal branch.. 176 
gastric branch 186, 184* 
glosso-pharyngeal.135*, 170, 181 
function of, 181, 182 
origin of, 134, 181* 
hypoglossal, 135*, 170, 186* 
function of, 182, 186 
origin of, 134, 137, 186* 
impulse, rate of, 149 
inferior maxillary, 176* 
intercostal, section, effect of, 103 
efferent impulses of,.... 112 
irritability of, 148 
diminished 148 
distinct from muscular,. 148 
restored 148 
lachrymal branch 176 
laryngeal recurrent branch. 183 
superior branch, 183 
lesion, restoration of, 149 
result of 149 
long ciliary branches 190 
mixed, 170 
most excitable stimulus for, 150 
motor, 170 
motor-fibres of muscles 244 
motor oculi, 170, 174* 
nasal branch 176 
neurilemma of 143, 144* 
ninth pair cranial (See 
Nerve Glosso-phar- 
yngeal). 
oculomotorius,...135*, 170, 174* 
function of, 174 
origin of 135*, 174* 
oesophageal branch... .183, 184* 
of eye 130, 192 
of heart 183, 184* 
of intestines 183 
of liver 67 
of lungs 102, 183, 184* 
of ovaries 255 
of pancreas 69 
of secreting organs 72 
of stomach 183,184 
of thorax 183 
of trachea 183 
of uterus 255 
olfactory, 135*, 170, 171* 
function of, 171, 172 
origin of, 135*, 171* 
ophthalmic 176 
optic, 135,170,172,173*,188*,192 
decussation of, 172 
function of, 173 
origin of, 135*, 172, 173* 
patheticus (See Nerve Troch- 
learis). 
pharyngeal branch 183 
phrenic, 103 
efferent impulses of, 112 
section, effect of, 103 INDEX. 
331 
Nerve or nerves, pneumogastric, 
135*, 170, 183, 184* 
function of, 183 
origin of, 135, 183, 184* 
section, effect of, 185 
property of, 148 
pulmonary branches 183 
reparation,time required for, 149 
second pair of cranial (See 
Nerve Optic). 
sensory, 170 
stniory fibres of muscles... 244 
seventn pair cranial (See 
Nerve Facial). 
short ciliary, 190 
sixth pair cranial (See Nerve 
Abducens). 
spinal accessory, 
135*, 170, 184,185* 
function of, 185 
origin of... 135*, 184, 185* 
superior maxillary, function 
of, 176 
origin of, 176* 
tenth pair cranial (See Nerve 
Pneumogastric). 
third pair cranial (See Nerve 
Oculomotorius). 
trifacial (See Nerve Trige- 
minus). 
trigeminus, or trifacial,.... 
..132, 135*, 170, 175, 176* 
function of, 175 
injury, effect of, 177 
origin of, 
132, 135*, 175, 176* 
troclilearis, or patheticus,.. 
..132, 135*, 170, 174, 175* 
function of, 174, 175 
origin of,132,135*, 174,175 
twelfth pair cranial (See 
Nerve Hypoglossal), 
vagus (See Nerve Pneumo- 
gastric). 
Nervous action on body or limb.92, 93 
apparatus, defined 169 
centres < r centres 138 
action in vocal and instru- 
mental music combined. 220 
action on organs 93, 105 
cells 138*, 140* 
bipolar, 138* 
multipolar, 138* 
processes of, 138* 
structure of, 138 
unipolar, 138* 
connections of, 125, 140 
defined 138 
functions of, 138, 139 
varieties of, 133, 139 
impulses, origin of 139 
impure hiood, effect on,. 83 
f Nervous cerebro-spinal system... 124 
defined 295 
disease, earthy phosphates in 
urine increased in, 239 
energy, origin of, 249 
excitability 140 
distinct from muscular 245 
gray substance, where most 
abundant 126 
location of, 124 
structure of, 124 
irritability 140 
distinct from muscular, 148 
neuralgia of face, nerve of, 177 
of head, nerve of, 177 
paralysis 149 
plexuses 161* 
system 124 
action of, 92, 124 
disturbed from want of salts 247 
divisions of, ,.. 124 
function of, 125 
importance of, 93 
impure blood, effect on, 83 
origin of, 260 
structure of, 124 
sympathetic system..124, 160, 161* 
white substance, location oi,.. 124 
structure of, 140 
Nervus octavus 295 
New-born child, jaundice of,.. .65, 26L 
New formations 271 
Nicotine, effect on iris, 190 
Night-blindness, 199 
Ninth pair cranial nerves (See 
Nerve Glosso-pharyngeal). 
Nipple, areola of, 262 
Nitrate of silver (internally), ac- 
tion on skin 225 
Nitrogen 295 
amount expired 108 
inspired 108 
diamagnetic properties of, Ill 
elimination of, 43 
in the body, importance of, 24, 116 
of mucosin 43 
repellent properties of, Ill 
requirement of in food 33 
Nitrogenous matter derived from, 26 
importance of, 26 
proximate principles 26 
Nitro-hydrocliloric acid (dilute), 
action on liver 66 
Noise, cause of, 208, 213 
Non-elastic connective tissue 270 
Non-nitrogenous matter, derived 
from,.*. 26 
proximate principles 26, 27 
division of, 27 
Nose, bleeding from defective 
membrane 176 
mucous membrane of, 39 332 
INDEX. 
Nose, origin of, 260 
nerve of, 176 
skin grafting on, 146 
sound vibrations through, 219 
Nostril, abnormal movement of, 
symptom of, 179 
Notes, deep bass, 212 
high pitch 212 
Nuck, canal of, 254 
Nuclei of epithelial cells 43* 
Nucleolus 295 
Nucleus, caudatus 130 
defined 295 
lenticuiaris 130 
Nutriment to the circulation 88 
Nutrition 26 
absorbed 55 
by enema 55 
cause of defective,.. 38, 41, 42, 271 
condition required for, 38 
defined 26 
derived from, 26 
during abstinence from t od..33, 69 
effect of, 249 
enters by two routes 76 
function of, increased 80 
impaired from want of bile 65 
importance of, 33 
most important ingredient for, 82 
nervous system affected by,... 83 
organs of, 46 
regulated. 72 
sodium chloride, importance in, 31 
substances required lor, 33 
through the skin 55, 231 
Oatmeal, nutriment in, 32 
starch in, 49 
Object, vision of, 193, 194 
Oculomotonus nerve. ..135*, 170, 174* 
fibrillse 13J* 
function of, 174 
origin oi, 132, 135*, 174* 
Odoriferous glands 227 
(Edema 295 
a cause of, 78 
of skin, a cause of, 84 
(Esophagus 47*, 63, 295 
acid secretion of, 41 
affected by ingesta 38 
function of, 40 
nerve of, 183 
peristaltic action of, 162 
stimulus of, 162 
secretion. 40, 51 
stimulation of, 73 
Oil globules of milk 28* 
of tissues 28 
origin of, 28 
Old age, skin wrinkles in, 226 
Oleaginous matter derived from,. 26 
as food 27 
Oleaginous proximate principle.. 26 
necessity of, 27 
Olein 28 
of milk... i 28 
Olfactory bulb 12G*, 130*, 171* 
centre 171*, 172 
nerve 135*, 171* 
origin of, 171* 
sensations 171 
Olivary body 126*, 134, 135* 
Omentum 295 
Ophthalmic nerve, function of,.. . 176 
origin ot, 176* 
Opium, action on pulmonary mem- 
brane 40 
effect on iris 190 
Optic chiasma 172 
commissure 135*, 172 
foramina 172 
r.e.-ve 135*, 170, 173*. 188* 
decussation of, 135*. 172 
tibrillse of, 130* 
origin of, 172, 173* 
section, effect of, 173 
thalamus 126*, 130* 
function of, 131 
haemorrhage, effect of, 127 
structure of, 130* 
tract 135* 
Organ or organs, 24 
continually active Ill, 147 
cause of, 112, 147 
defined 23 
derangement, a cause of, 33 
normal actions, cause of, 92 
functions, importance of,... 82 
of Corti 211*, 212 
cells of, 211*, 212 
importance of, 214 
of touch 145*, 224 
nutrition of, 72, 100 
regulation of, 72 
secreting nerve-fibres 135 
sensations of, 105 
sensitiveness of, 92 
stimulation of, 92,139 
sympathy of 163 
Organic activity, primary cause 
of, 92, 93 
action maintained 141 
food required for,. . ... . 110 
bodies, aggregation by, 23 
differ fiom inorganic 23 
decay 24 
faculty .163, 164 
low animal life, missing link of, 93 
matter, expired 108 
reflexes 139 
repair 24 
representation 168 
salts, changes of, 238 
world involves 23 IXDEX. 
333 
Organisms 23 
distinguished from inert bodies 251 
function of, 23 
growth of, 23 
requirements of,, 24 
similarity in, 24 
structure of, 23 
Organum tactus 145*, 146*, 225 
ether spray, effect on, 65 
Orgasm 259 
Orifice, cardiac, 46 
of ductus communis choledo- 
chus 68* 
of pancreatic duct 68* 
pyloric, 46 
Os externum of uterus 252* 
internum of uterus 252* 
Osmosis, defined 78 
Osseous labyrinth of ear 206, 292 
spiral lamina 210, 211* 
Osteomalacia 30 
cause of, 30 
Os uteri 252*, 253* 
Otic ganglion 160, 161*, 210 
Otoconia of ear 207. 208* 
Otoliths of ear 207, 208* 
Ova 256 
abnormal descent of, 254 
cleavage of, 260 
development of, 256 
discharge of, 256 
fertilization of, 252*, 259, 268 
impregnation of, 259* 1 
maturation of 256* 
number of, 256 
passage of, 253 
prematurely liberated 256 
segmentation of, (See C.eavage). 
structure of, 256 
undeveloped, 256* 
Ovarian arteries 255 
ligaments 252, 253* 
nerves 255 
stroma 255 
tubes 253* 
Ovary 253*, 255, 256 
corpus luteum of, 256*, 257 
Graafian vesicles of, 255 
scar on, 257 
size of, 255 
structure of, 255 
Overtones 214 
Oviducts 253* 
Ovisacs 255, 256* 
Ovula of Naboth 253 
Ovulation 256 
Ovules of plants 269 
Ovum (See Ova). 
Oxidation 295 
in the animal economy, a mis- 
nomer 114, 115 
Oxygen 295 
Oxygen absorption in lungs. .104, 112 
cause of, 106 
action on lungs 105, 136 
amount absorbed in lungs 101 
expired 108 
inspired 108 
and carbonic acid 106 
exchanges of,102, 104, 105 
entering the body 113 
from plants 1'0 
given off by plants 23, 24 
to animal tissues 106 
in blood 80, 111 
in body 24 
in lungs 104 
magnetic properties of, Ill 
of haemoglobin 35, 106 
paramagnetic property of, Ill 
required in muscles 247 
use in the economy 115 
use in respiration 110 
Pabulum 295 
origin of, 249 
Pacinian bodies 146, 225 
structure of,....! 146* 
Pain, insensibility to,. 145, 146 
Painful impressions 145, 165 
Pal matin 28 
of milk 28 
Palm oil 29 
Palate, nerve of, 178 
Palpebrae 192 
Palpitation of heart, a cause of,.. 84 
Pancreas 68* 
a gland 67, 71 
blood-vessels of, 69 
ducts of, 67, 68* 
lymphatics of, 69 
nerve-fibres of, 69 
structure of, 67, 68 
weight of, 62 
Pancreatic duct, orifice of, .46, 57, 68* 
juice 67 
action of, 68 
on starch 27, 34, 68 
alkaline reaction 68 
analyzed 68 
constituents of, 68 
effect on acid 50 
on chyme 50 
emulsifies fat 29 
origin of, 54 
property of, 34 
quantity of, 68 
secretion of, 50, 71 
stimulus of, 73 
Pancreatin 34, 68 
an albuminoid 34 
function of, 34 
origin of, 50, 54 
1 quantity daily secreted 34, 68 334 
INDEX. 
Papillae of the skin 223* 
Paralysis, muscular, 149 
nervous,, 149 
nutrition diminished in, 100 
two great divisions of, 149 
Paraplegia 157 
Parenchyma 295 
Parotid glands 125, 295 
Parturition pains, centre for, 155 
Pathetic 295 
Pathetic nerve (See Nerve Trocli- 
learis). 
Pathogenytes 39, 273, 296 
origin of, 39 
Pathology 296 
Peas, starch in, 49 
Pelvic organs, nerves of, 155 
region, paralysis, seat of lesion 
in, 157 
Pelvis 296 
Penis, erection of, 259 
Pepsin 34 
action of, 34, 52 
ceases in duodenum 50 
on stomach 56 
pain from, 56 
administration, caution in, 56 
an albuminoid 34, 52 
as such, not absorbed 54, 55 
change of, 50 
coagulation of, 55 
defined... 52 
precipitation of, 50, 53, 55 
secretion of, 34 , 42, 50, 51, 54 
cause of. 60 
daily quantity of, 34 
stimulus of, 48, 49 
Peptone or peptones 52, 53 
as such, not absorbed 53 
broken up 50 
by Lehman 53 
distinguished from albumen 53 
origin of, 52, 53, 54 
precipitated 53 
termination of, 52, 53 
Pericardium 89, 296 
Perilymph of ear 206 
Perimysium externum 241, 242* 
internum 241, 242* 
Perineum 296 
Periodic fever 274 
Periods, monthly 266 
Periosteum 270 
Peristalsis, explained 98, 99 
Peristaltic action 296 
cause of, 48 
contraction 60 
Peritoneal inflammation, chronic, 
a cause of, 84 
Peritoneum 254, 256 
Peritonitis 296 
respiratory movements in,.... 107 
! Person underwater, time, limit of. 107 
Perspiration, effect on respiration 108 
on temperature.... 123, 227, 228 
from mental excitation 125 
insensible, 227 
odor of, 108 
secretion of, 71, 227, 228 
sensible, 227 
temperature lowered by,.. 114, 227 
through mental depression.... 73 
excitement 73 
water given off during 29, 30 
Perspiratory glands of skin 
71, 223*, 227 
of dog’s skin 108 
Perspired air, acid reaction of,.... 73 
Pes hippocampi 171 
Petrous portion of ear 204 
Peyer’s glands 59, 60 
ulceration of, 60 
patches 59 
Phagedenic 296 
Pharynx, nerve of, 181, 183, 185 
Phonation 220, 296 
Phosphoric acid, in brain 127 
Phthisis 38, 296 
a cause of, 38 
diarrhoea in, 60 
Peyer’s glands affected in 60 
Physical action, disintegration by, 74 
material for, 249 
reaction 92 
change 53, 296 
energy 139 
inferior to vital power 109 
transformation of,.... 249 
forces of life 93, 94 
laws of the body 92, 93 
power, limit of, 109 
parts, natural tendency of,... 93 
Physic 66 
Physiological energy 139 
Physiology, defined 23 
Physostigmine, effect on iris 190 
Phytolaccine, effect on dog’s liver 66 
Pia mater 296 
of spinal cord 153* 
Pigment deposits in skin 222 
Pilocarpine, action on pulmonary 
membrane 40 
Pineal gland 126*, 130*, 131 
Pinna of external ear 200, 201* 
Pituitary gland 71 
Placenta 265* 
formation of, 261 
importance of, 261 
Plantar reflex 142 
Plant or plants as food, principal 
constituents of, 27 
necessity of, 27, 32 
carbonic acid,absorption by, 110 
coloring matter of, 23, 36 INDEX. 
335 
Plant or plants, decay, a cause of, 36 
essential substance of,... .27, 36 
function of, 23 
growth of, 23 
heat of 123 
life action depends on organs 23 
nutrition of, 23, 36 
oxygen given off, 24 
pollen of, 269 
reproduction of, 269 
respiratory organs of, 110 
solar light, effect on, 23 
(See Vegetables). 
Plasma of blood 79, 82, 85 
Plethora 297 
a cause of, 81 
Pleura 297 
Pleural cavity, result of air in,... 108 
Plexus or plexuses, aortic, 161* 
cardiac deep and superficial 161* 
cervical, 161 
coeliac, 67 
epigastric, 161* 
hepatic, 67, 162 
hypogastric, 161 * 
lumbar, 162 
of nerve-fibres 144 
of skin 144 
pulmonary, 162 
renal, 161* 
sacral, 162 
semilunar, 161* 
solar, 161* 
spermatic, 161* 
Pneumogastric. 297 
Pneumogastric nerve (>ee Nerve 
Pneumogastric). 
Pneumonia, symptom of tempera- 
ture in, 122 
Pneumothorax 108, 297 
Podophyllin, action on dog’s liver 66 
Poison, effect, difference of, 83 
of food 274 
of the system 82 
retention in the blood 83 
tyrotoxicon, 274 
Politzer’s ear-bag, use of, 206 
Pollen of plants 269 
Polyps, reproduction of, 251 
Polypus 266, 297 
Pomum Adami 218*, 219 
Pons Varolii 126*, 130*, 135*, 297 
function of, 132 
structure of, 132 
Portal circulation 96, 97 
system 76 
vein 62, 63* 
distension, relieved by, 70 
effect of pressure on, 70 
formation of, 62 
Posterior chamber of eyeball 188* 
Potassium carbonate 29 
| Potassium chloride 29 
effect on blood 79 
iodide, absorption of, 56 
phosphate 29 
salts given off in tissues 106 
necessity of, in muscles 247 
sulphate 29 
urate, increase of, in urine 238 
Potatoes, starch in, 49 
Potential energy 118, 297 
Pouch of Douglas 254 
Processus brevis 204 
gracilis 204 
Pregnancy ... 259, 261, 262, 268 
corpus luteum of, 257 
extra-uterine, 261 
in absence of menstruation... 267 
nausea or vomiting of, 141, 264 
quadruple, 262 
simulation of, 265 
twin, 262 
Premature delivery through fright 141 
Presbyopia 198 
Pressure, arterial, 95 
cardiac, 90 
sense of, 145, 146 
Property, defined 139 
Prostate gland, hardened, result of,239 
Proteids 50, 54, 273 
coagulation of, 55 
composition of, 54 
compound 54 
defined 54 
origin of 50 
secretion of, 50 
Protein bodies 54 
compounds 54 
Protoplasm 297 
changes of, 248, 249 
origin of, 249 
power of, 93 
Proximate principles 26 
Psychical deafness 216 
deafness 216 
Psychology 169, 297 
Ptomaine 38, 273, 297 
action of, 38 
disease influenced by, 38 
origin of, 38 
prevented by bile 274 
Ptosis 174 
Ptyalin 34 
action of, 49 
an albuminoid 34 
origin of, 50, 54 
secretion of, 50 
Puberty 266 
change of voice at, 219 
Puerperal fever, a cause of, 255 
Pulmonary alveoli, membrane of, 40 
artery 90*, 102*, 104* 
membrane affected by, 40 336 
Pulmonary plexus 162 
tuberculosis, a cause of, 38, 39 
vessels 102*, 104*, 105* 
Pulsation of the heart 91 
and respiration, in unison, cause 
of, 112 
arterial, 95 
capillary, 95, 96 
Pulse, abnormal, 96 
below normal, a symptom of,.. 122 
dicrotic, cause of, 96 
indication of, 96 
feeble, indication of, 96 
full, indication of, 96 
in hydrocephalus 96 
internal haemorrhage,symptom 122 
low, from bile in blood 65 
measure of, 96 
rates 96 
slow, in apoplexy 96 
unison with temperature 121 
Punctum proximum of sight 194 
remotum of sight. 194 
Pupil ..189 
contraction of, 189, 190 
centre for, 190 
remedies for, 190 
dilatation of, 190 
by atropia 125 
centre for, 155, 190 
permanent, 174 
remedies for, 190 
through terror 141 
reflex 142 
Purgatives 65, 66 
Purkinje, vesicles of, 256 
Pus cells, or corpuscles 81 
Putrefaction 298 
Pyaemia 298 
due to, 274 
Pyloric orifice 46 
sphincter 57 
Pyramids 135* 
anterior, 126* 
posterior, 134 
Quadruple pregnancy 262 
Quality of a note 213, 214 
of food 33 
of sound ! 214 
Quantity of food 61 
Rachitis 298 
a cause of, 30 
Radiation of energy 196 
of light 196 
Rales, crepitant, 106 
Range of eye accommodation.... 194 
Reason 129 
loss of, 129 
power limited 93 
Receptaculum chyli 75, 76* 
INDEX. 
Rectum 47* 
nerve-fibres of, 154 
Red blindness 197 
Red blood-corpuscles 79, 80*, 106 
anaemia of 106 
effect on circulation 80 
on motion 80 
on nutrition 80 
on respiration 80 
excessive, effect of, 81 
form of, 79, 80 
function of, 79, 80 
haemoglobin of 
... .35, 79, 80, 106, 289 
importance of, 80 
number in blood 79 
diminished 81, 83, 84 
chlorosis from.... 83 
origin of, 80 
plethora from, 81 
size of, 79 
substances given off 106 
water absorbed by 79 
when broken up 106 
Reflex action, affected by,... .139, 140 
inhibition of,..139, 156, 162, 291 
interierence with, result of, 94 
of the medulla oblongata.. 92 
organic, 139 
requirements for, 140 
various agents of, 140* 
convulsions from, 141 
excitability, diminished 139 
increased 139 
impulses 138 
movements 140 
Refracted rays 197 
Regeneration of muscles.245, 247, 248 
of nerves 148, 149 
Reissner’s membrane 211* 
Relapsing fever 274 
Reminiscence 168 
Remittent fever 274 
Renal papillae 233, 234* 
pelvis 233, 234* 
plexus 161* 
pyramids 233, 234*, 235 
Repair and decay 23 
Reproduction, animal, 251 
vegetable, 269 
Reproductive cells, no interference 
by, 251 
Resonance, defined 214 
in posterior cavity of nose.... 219 
Respiration 101 
air renewed by, 106 
and pulsation in unison, cause 
of, 112 
artificial, 275 
carbonic acid in, 110 
centre (See Respiratory centre), 
cutaneous, 112, 113, 114 INDEX. 
Respiration, difficult, cause of,105,116 
effect on temperature 119 
frequent,when skin hot and dry 108 
forced, cause of, 107 
hurried, 105 
in animals under water 116 
in deficient oxygen, result of,.. Ill 
influence on animals 108, 116 
influenced by, 80 
in high temperature 105 
muscles of, 107 
number of, 106 
of cold-blooded animals 110 
oxygen, use in, 110 
perspiration, effect on, 108 
promoted, in infant 117 
sensory nerve of, 183 
slow, from bile in blood 65 
stimulus for,.105, 110, 111, 112, 136 
from mind 110 
water exhaled during, 30 
Respiratory activity, cause of,.... 
91, 111, 112 
air passages, epithelium of,.... 42 
artificial excitants, effect of,... 113 
centre 103, 135, 136 
action of, 105 
reflex action of, 110, 112 
energy, primary cause of, 119 
expansion of abdomen 107 
of chest 107 
functions, effect of cold on,... 136 
impulses 136 
irregularity, danger of, 136 
mucous membrane 40, 42 
muscles, activity by reflex 112 
nerves of, 155 
nerves 103 
organs, movement of, 106 
stimulus not counteracted, re- 
sult of, 107 
vesicular murmur 106 
Respired air, change in, 108 
Rest, absolute, not in nature 119 
Restiform body 126*, 134, 135* 
Resting after meals, effect on di- 
gestion 50 
Rete mucosum layer of the skin.. 222 
testis 258* 
Retiform connective tissue 270 
Retina 172, 188*, 191* 
blind spot of, 196 
cones of, 191*, 196 
impressions, duration of, 196 
image on, 193 
macula lutea of, 191 
rods of, 191*, 196 
stimulation of, 196 
structure of, 191* 
Retroflexion of uterus 298 
Retroversion of uterus 298 
Rhinoplasty 146 
Rheumatism, temperature symp- 
tom in acute, 122 
Rhythm of the heart 91 
Rice, nutriment in, 32 
starch in, 32, 49 
Rickets (See Rachitis). 
Rima glottis 217, 218* 
regulation of, 137 
Rods of Corti 212 
of the retina 191*, 196 
Round ligaments 252, 253*, 254 
Rye flour, starch in, 49 
Saccharin 299 
Saecharum, food necessity of 27 
matter derived from,.. 26 
proximate principle 26 
Saccule of ear 202*, 207, 208* 
Sacculus laryngis, action during 
vocalization 219 
Sacral plexus 162 
vertebrae 151* 
Sago, starch in, 49 
Saline cathartics 66 
proximate principles 26 
Saliva, action on starch . .34, 49 
active principle of, 34 
amount of daily secretion 34 
deficient, effect of, 51 
effect on oesophagus 51 
expectoration of, injurious.... 51 
ptyalin of, 34, 49 
reaction of, 73 
secretion of, 71 
by reflex influence 73, 228 
centre of, 135 
stimulus of, 73, 125 
Salivary glands 71, 74, 125 
function of, 40 
nerve-fibres of, 72 
weight of, 62 
Salt, absorption of, 77 
acetate, action on kidneys 238 
action on bowels 77 
defined 238 
derived from, 26 
given off in tissues 106 
lactate, action on kidneys 238 
laxative 77 
quantity in blood 81 
tartrate, action on kidneys 238 
water, not osmotic 37 
Sanguinarine, action on liver 66 
Saponification 299 
Saprophytes 39, 273, 299 
Sarcolemma 242*, 243, 244, 299 
Sarcoma 299 
Scala media 211* 
tympani 202*, 211* 
vestibuli 202*, 211* 
Scalse of cochlea 211* 
Scammony, an action of, 66 338 
INDEX. 
Scarlatina, temperature symptom 122 
Scarlatinal rheumatism, blood in, 87 
Sclnzomycetes 273, 299 
Schneiderian membrane .171* 
Schwann, white substance of,143,144* 
Science, object of, 109 
Sclerotic coat 187, 188* 
structure of, 187 
Scorbutus 299 
Scrofula 299 
Scurvy 299 
Sebaceous glands 71, 223*, 228 
secretion, action of, 228 
composition of, 228 
flow of, facilitated 226 
Sebum 228 
Second pair cranial nerves (See 
Nerve Optic). 
Secreted matters, origin of, 71, 72* 
Secreting activity, by reflex, 72 
intermission of,. 73 
energy, primary origin of,... . 119 
ceds 71, 72* 
regulation of, 72 
variety of, 42, 43, 71 
follicles..... 71, 72* 
epithelium of, 42 
glands 71, 72, 75 
epithelium of, 42 
nutrition of, 71 
variety of, 71 
organs 71 
impulses for, 72 
inhibitory nerve-fibres of,.. 72 
motor nerve-fibres of, 72 
nerve-fibres of, 72, 135 
nutrition of, 71 
origin of, 260 
sensory nerve-fibres of,.... 72 
temperature of, 73 
trophic nerve-fibres of, 72 
variety of, 71 
Secretion or secretions, reaction of, 73 
defined 71 
effected by cells 71 
final resuit of, 71 
increased acidity of, 41 
material for, 71 
nerve impulses for, 72 
of acid reaction 73 
of alkaline reaction 73 
of colostrum .263, 272 
of fluids 71 
of gases 71, 82, 108 
of semisolids 71 
of solids 71 
varieties of, 71 
Section of spinal cord, effect of,155,156 
Sedatives, action on cells 65 
Sedatives, diminish organic sensa- 
tion 65 
Seelentaubheit 216 
j Semen 258, 259 
Semicircular canals 
201*, 202*, 206, 208*, 209 
fluid of, 208 
nerve-fibres of, 180,208 
Semilunar ganglion 176 
plexus. 161* 
valves 90* 
Semisolids, secretion of 71 
Sensation 139, 163, 165, 168 
appreciation of external,48, 111. 165 
discrimination of, 164 
elements required in, 168 
external, cells of 128 
in the organ,48, 111, 145,146,165 
diminished by sedatives.... 65 
organic,.. .48, 111, 145, 146, 165 
illusion of, 169 
in animals 164 
internal, organ of, 163, 165 
of hearing 163, 165, 180 
of light 192 
of sight 163, 165 
of smell 163 
of sound 200 
of taste 163 
of touch.. 163 
diminished by sedatives 65 
organic, 165, 166 
primary cause of, 92 
requirements for, 48, 168 
stages of 149 
Sense, an organic faculty 163 
defined 163 
external,.. 48,111, 145,146,165,197 
five kinds of, 139 
internal, 163, 165 
four kinds of, 139 
organs of, 126, 139, 163, 165 
locality of, 163 
of hearing 180, 212, 213, 215 
centre of, 169, 180*, 216 
nerve of, 135, 180 
organ of, 200, 211 
of sight 173, 191, 196 
centre of, .... 169, 173 
nerve of, 135, 173 
organ of, 187, 188 
of smell 163, 171, 172 
centre of, 169, 172 
nerve of, 171 
of taste 182 
centre of,..135, 169, 172, 181* 
nerve of, 181 
of touch 145 
modified by cuticle 225 
most important 146 
organs of, 139, 224 
organs .144, 145, 224 
accustomed to impressions. 169 
endowment of, 98 
impressions retained 169 INDEX. 
339 
Sense organs, stinmlation, limit of 169 
internal, 165 
Sensitive memory 139, 163, 165 
defined 168 
Sensory aphasia 220, 221 
brain-tibrilhe, tract of, 130 
currents, rapidity of, 149 
nerve-fibres 72 
of muscles 244 
origin of, .. 170 
nerves 170 
Septicaemia 299 
Serous coat of membranes 58* 
secreting cells 71 
fluid, reaction of, 73 
secretion of, 71 
membrane 39, 299 
abdominal, 254 
endothelium of, 42 
formation of, 260 | 
Serum of blood, composition of,.. 85 
origin of, 82 
Seventh pair cranial nerves (See 
Nerve Facial). 
Short-sightedness 197 
Sight 196 
accommodation facilitated 188 
affected, from fifth nerve 177 
an external sense 168 
area, fibrillte tract .* ... .130* 
cerebral area of, 173* 
centre of, 169, 173* 
in old age 198 
nerve-hbres of, 135, 172 
organ of, 187, 188* 
(See Vision). 
sense of, 173, 196 
stimulus of, 146, 173, 196 
Sigmoid flexure 47* 
Sinus of kidney 233 
Sixth pair cranial nerves (See 
Nerve Abducens). 
Skin, absorbing organ 231 
absorption of food 55, 231 
activity, stimulus of, 147 
affected by temperature 226 
alkalies, strong, action on, 231 
appendages of, 226, 229 
blackened by silver nitrate.... 225 
blood supply for, 231 
bronze comr of, 240 
capillaries of, 98 
carbonic acid given off by, 112 
coloring matter of, 35 
due to melanin 35, 222 
colored spots of, 231 
comedo of, 229 
corium of, 223*, 224, 225 
cuticle of, 222, 223* 
cutis of, ' '223* 
vera of, 224 
dandruff of, 222 
Skin, derma of, 223*, 224 
dermis of, 2'3*, 224 
epidermis of, (See Epidermis). 
epithelium of, 42 
excretion by, 74, 227 
amount of, 231 
fat cells of, 223* 
fluids, regulation of, 226- 
freckles of, 223 
function of, 74, 222, 227, 231 
glands of, 228*, 227, 228 
grafting (nose) 146 
haemorrhage in, 231 
hot, dry, effect on respiration 108 
in old age, wrinkles of 226 
keratin of, 35, 222 
limiting evaporation from blood- 
vessels 223 
lymphatics of, 231 
melanin of, 35, 222 
muscles of, 223*, 226 
muscular fibres of, 226, 250 
nerve-fibre plexus of, 144 
nerve supply of, 231 
oedematous, a cause of, 84 
of head and face,nerve-fibres of, 135 
papillae of, 223*, 224 
blood supply of, 225, 231 
pigment of, 222, 240 
protection by, 231 
radiation of heat 226 
rete mucosum of, 222 
secreting and excreting organ. 228 
sensation diminished by ether 
spray 65 
soda, action on, 231 
stratum corneum of, 222 
granulosum of, 222 
lucidum of, 222 
Malpighii 222 
structure of, 222 
sunburnt complexion of, 223 
tension of, 226 
thickness, variation of, 225 
tissues, origin of, 260 
varnished 112 
water absorbed by, 55, 231 
eliminated by, 30, 123, 231 
Sleep, carbonic acid diminished 
during, 113 
energy, use of, during, 33 
Smell 169, 171, 172 
and taste, co-ordination of, 182 
an external sense 163 
centre of, 135, 169, 172 
location of, 172, 177 
condition necessary for, 171 
illusion of, 169, 172 
impairment of, 171, 172, 176 
sense of, 171 
stimulus of, 172 
stimulation of, 146 340 
INDEX. 
Small-pox, parasitic life, 82 
poison of, 82 
not detectable in blood.. 82 
temperature, symptom 122 
Snow-blindness 199 
Sodium, acetate, action on kidney 238 
benzoate, effect on dog’s liver. 66 
blood affected by strong, 79, 81 
carbonates 29 
action on muscles 247 
chloride.... 29, 31* 
elimination of, 31 
importance of, 31 
necessity in muscles 247 
phosphate 29 
action on liver 66 
salicylate, action on liver 66 
sulphates 29 
action on liver 66 
urate in urine, increased 238 
Solar light, effect on vegetables... 23 
plexus 161* 
Solids, active principles of, 34 
dissolving, cause of, 119 
secretion of, 71 
Solitary glands of intestine.58, 59*, 71 
Somnambulism 299 
Sondhaus, sound experiments by, 213 
Soul, defined 129 
emotion, effect on heart 94 
the vital principle 94, 166 
Sound, a quality 196, 212 
amplitude of, 213 
analysis by ear 216 
characteristic of, 213 
defined 212 
dispersion of, 214 
echo of, 214 
effect in ear 215, 216 
impression of, 215 
intensity of, 216 
pitch of, 213, 214, 215, 216 
quality of, 213, 214, 215, 216 
timbre of 214 
in the medium 212, 219 
intensity of, 213, 215 
loudness of, 213 
modification in ear 215 
motion of, 214 
musical tone of, 213 
overtones 214 
periodic vibrations, limit of,... 213 
pitch of, 213, 215 
quality of, 213, 214, 215 
resonance, defined 214 
increased by meatus exter- 
nus 201 
sensation of, 169, 180, 216 
timbre of, 214, 216 
transmission in ear 215 
velocity of, 196, 213 
vibrations of, 213 
Sound, wave-length of, 213 
waves, rarefied 213 
reflective, 213 
refractive, 213 
Sound-clang 214 
Spasm 300 
Speech, articulation defective.... 220 
difficult 137 
nerve of, 186* 
centre, location of, 220 
co-ordination centre 135 
defined 220 
muscles required for, 217 
resonance of, 219 
Spermatic fluid, reaction of, 73 
secretion of, 258 
•plexus 161* 
Spermatozoon and ovum, meeting 
place of, 259 
origin of, 258 
production of, 255 
Sperm-cell, production of, 255 
Sphacelus 300 
Sphincter ani 154 
nervous centre for, 155 
vesicae 156 
nervous centre for, 155 
Sphincters, action of, 93 
natural tendency of, 93 
Sphygmograph 96 
Spinal accessory nerve 
‘....135*, 170, 184, 185* 
anterior nerve-roots 152* 
column, distortion of, 30 
divisions of, 151* 
structure of, 151* 
vertebrae of, 151* 
Spinal cord 152*, 153* 
anterior columns of,..152*, 153* 
arachnoid of, 153* 
blood supply of, 155 
central canal of, 127*, 152* 
centres, functions of,. .,154, 156 
protection of, 160 
cervical enlargement 155 
portion, danger of lesion 
in, 157 
dorsal enlargement of, 155 
dura mater of, 153* 
gray substance of, 153* 
impulses, passage of, 154 
speed of, 149 
lateral column 152* 
lesion, determination of,... 157 
lumbar enlargement of, 155 
medullary substance, struc- 
ture of, 144 
motor nerve-fibres 152* 
normal actions of,..155, 156, 157 
pia mater of, 153* 
posterior columns of, 152* 
reflex centres 155 Spinal cord, section, effect of,.103, 155 
sensory nerve-fibres of,.... 152* 
sixth ventricle of, 127* 
structure of, 152*, 153* 
tabes dorsalis of, 301 
three great divisions of func- 
tions 156 
white substance of, 152* 
foramina 151* 
nerves 153* 
exit of, 154 
ganglia of, 153* 
structure of, 154 
posterior nerve-roots 152* 
Spirits, depression of, Ill 
Spleen 47*, 63*, 68* 
a gland 69, 71 
a storehouse 70 
blood-corpuscles (red) decom- 
posed in, 62 
blood supply of, 69 
diverticula of, 70 
enlarged 70, 84 
function of, 69 
malaria, effect on, 70 
not absolutely necessary to life 69 
situation of, 69 
size diminished 70 
structure of, 69 
weight of, 69 
Splenic artery 68*, 69 
hyperemia 84 
hyperplasia 84 
tumor 84 
vein 68*, 69 
Spontaneous 300 
generation 273 
Squamous epithelial cells 44* 
Squinting from defect of nerve... 178 
St. Paul’s (London), sound reflec- 
tion in, 213 
Stammering a cause of, 221 
Starch, carbon of, 27 
conversion of, 27, 29, 34 
derived from, 26 
effect on stomach 41 
final disposition of, 29 
origin of, 28 
pancreatic juice, action on, 27,49,68 
partly not changed 49 
proximate principle 28 
raw, indigestible 49 
saliva, action on, 34, 49 
when injurious 52 
Starvation of body, a cause of,..38, 39 
Stearin 28 
Sterile 300 
Sterility 258 
Still-born 275 
fctimuli, limits of, 169 
logarithm of, 293 
Stimulation of organs 139 
INDEX. 
Stimulus and effect 197 
defined 800 
for circulation 91, 92, 110 
for respiration 105,110, 111, 112, 136 
physical, 125 
physiological, 125 
to auditory nerve, 215 
to lungs 105, 110 
Stomach 47*, 63* 
absorbents of, 61 
absorption by, 55 
acid of, 42, 51 
action by reflex 48 
alcohol, effect on, 41, 52 
alkalinity of, 49, 51, 56 
capacity of, 47 
continually active, injury of,.. 49 
contraction, cause of, 124 
digestion in 48, 49, 50, 51 
disease, effect on, 49, 50 
nourishment in, 55 
epithelium of, 48 
exhaustion of, 49 
fermentation of, 55 
follicles of, 47, 48, 72* 
gas in 55 
irritated, effect of, 41 
membrane, protection of, 56 
motion during digestion 49 
mucous membrane of,...39, 47, 72* 
mucus, secretion of, 48 
muscular fibres of, 246 
nerves of, 183 
nervous action of, 50 
pain, from pepsin 56 
pepsin not secreted in empty,. 56 
secretion of.... .34, 42, 50, 51, 52 
perforation, by gastric juice... 56 
peristalsis 60, 162 
cause of, 48 
stimulus for, 48, 60, 147 
protected lrom digesting itself. 56 
secretion of, 48, 50, 51, 52 
by empty, 49, 56 
cause of 50 
stimulus of, 60, 73, 147 
(See Gastric). 
starch, effect on, 41, 52 
structure of, 47 
sugar, effect on, 41, 52 
sympathy with liver 141 
veins 63* 
wrong treatment of, 51 
Strabismus, external, 174 
from defect of nerve 178 
from indigestion 141 
from paralysis 192 
Stratum corneum of skin 222 
granulosum of skin 222 
lucidum of skin 222 
Malpighii of skin 222 
Striated muscular fibres 241, 242*, 243* 
341 INDEX. 
Strychnine, action of, 157 
spasm from, 158 
Stuttering, a cause of, 221 
Subarachnoid space 207 
Subcutaneous tissue 226 
Submucous coat; 58* 
Sudoriparous ducts, gas secretion 
by, 109 
glands 71, 223*, 227 
Sugar, carbon of, 27 
derived from, 26 
effect on stomach 41, 52 
final disposition of, 29 
formation, in liver 66 
in blood, decomposition of,. .66, 67 
quantity of, 81 
in hepatic veins 28 
in urine, a cause of, 67 
of food, derived from, 27 
disappearance of, 27 
necessity of, 27 
of liver, origin of, 27 
of milk, origin of, 27 
transformation of, 32 
origin of, 27, 28 
proximate principle 26, 27 
when injurious 41, 52 
Sulphur, importance of, 116 
Sulphuric acid and water, heat of, 120 
Sunburnt complexion, cause of,... 223 
Sunlight, effect on vegetables.... 23 
Superior maxillary nerve 176* 
Suprarenal capsules 71, 239, 240 
melasma 240 
Swallowing (See Deglutition). 
Sweat, amount of water perspired 228 
as such, not in blood 108 
composition of, 228 
effect on temperature 228 
glands 71, 223*, 227 
insensible 227 
nervous centre for, 228 
secretion of, 227 
sensible 227 
Sweating in high temperature, 
cause of, 105 
Swimming, danger of, with perfor- 
ated membrana tympani... 204 
Sylvian aqueduct 127* 
fissure 125*, 126, 300 
Sympathetic ganglia... .125, 153*, 160 
as protectors ' 160 
nerve, section, effect of, 119 
nervous centres, functions of,.. 162 
system 124, 160 
functions of, 160, 162 
Sympathy in actions 125 
of organs 160 
importance of, 141 
Syncope 94 
Syphilis, retained in blood 83 
System, defined 24 
Systole of heart 91 
Tabes dorsalis 801 
j Tactile corpuscles 145*, 224 
ether spray, local effect on,. 65 
structure of, 145* 
Taliacotian operation 146, 801 
Tannic acid, action on collagen... 85 
effect on hides 85 
impairs digestion 55 
Tapioca, starch in, 49 
Tarsus of eyelid 198 
Tartrates, changed in blood 238 
Taste and smell, co-ordination of, 182 
bulbs 147*, 182 
centre for, 169, 172, 181* 
differences of, 182 
impaired 177 
impressions retained 188 
nerve of, 177, 181 
nerve-fibres of, 135, 175, 177 
papillae of, 182 
(See Gustatory). 
sense of, 182 
depends on terminal bulbs. 147 
stimulation for, 146 
Taurin 301 
Taurocholin. importance of, 66 
Tea, effect of, Ill 
Tears, alkaline reaction of, 73 
as such, not in blood 108 
secretion of, 71 
Teeth, lime phosphate of, 30 
lower jaw, nerve of, 176, 177 
upper jaw, nerve of, 176 
Tegmentum cerebri 130*, 132 
Temporal muscle 177 
Temperaments 301 
Temperature, abnormally high, 
danger of, 121 
as a detective 121 
below normal, symptom of,.... 122 
different from heat 120 
during digestion 50 
effect on gas 102 
on liquid. 102 
on muscles 245 
on muscular contraction.... 246 
on skin 226 
equalized 119 
external, unreliability of, 121 
Fahrenheit degrees changed in- 
to Centigrade 120 
high, effect on heart 136 
on lungs 136 
on tissues 119 
pulsation accelerated from.. 112 
respiration accelerated from, 112 
stimulus on ceils 112 
symptom of, 122 
highest and lowest in the body 120 
in iirigbt’s disease 121 INDEX. 
343 
Temperature, in tuberculosis, a 
symptom of, 122 
importance of, 121, 123 
limits of, in the economy 121 
low, from b'le in blood 65 
lowered artificially 114 
by perspiration 114, 228 
lowest in the economy 120 
moderation of, when high 123 
normal, maintenance of, 121 
of arterial blood 73, 119 
of body 114, 118 
of fevers 123 
of measles 122 
of old age 122 
of secreting organs 73 
of tetanus 122 
of typhoid fever 123 
of venous blood 73, 119 
periodical rise of, 114, 115 
physiological lowering of, 114 
pulse unison with, 112, 121 
standard maintained 119 
when fatal 120, 121 
Tendons 270, 301 
formation of, 242 
Tenesmus 301 
Tenth pair cranial nerves (See 
Nerve Pneumogastric). 
Tentorium cerebelli 126*. 132 
Terminal bulbs, 147 
structure of, 147* 
varieties of, 182 
plates 147*, 244 
Tessellated epithelial cells 44* 
Testes 71, 258* 
Tetanus 301 
bacilli of, 122 
cause of, 158 
convulsions from, 157 
from a wound (traumatic) 157 
temperature in, 122 
Thebesius, valve of, 90 
Thermometer 120* 
Third pair cranial nerves (See 
Nerve Oculomotorius). 
Thirst, sensation of, 61 
Thoracic duct 75, 76* 
organs, nerves of, 155 
Thorax, nerves of, 183 
Throat, resonance in, 219 
Thrombi, difference in, 86 
in arterial blood,landing spot of, 86 
in venous blood, landing spot of, 86 
Thrombus of vessel, effect of,..86, 271 
Thymus gland 71, 301 
Thyro-aryteenoid muscle 217, 218* 
Thyro-epiglottideus muscle 217 
Tnyroid cartilage 102*, 218* 
gland 71 
Tissue or tissues, albuminous in- 
termediate substance of, 272 
Tissue or tissues, acid 41, 109, 248 
neutralization of, 82 
change,, cause of, 74, 119, 249 
connective, 270 
decay and repair of, 249 
decomposition of, 249 
defined 24 
disintegration of: 74, 272 
from high temperature.. 119 
energy, primary origin of,.. 119 
fat of, ~ 28 
formation of, elements re- 
quired for, 50, 116 
modification of, 249 
no elementary change in,.. 241 
nutriment for, 82, 83, 105 
absorbed by, 106 
oil of, 28 
oxygen supply to, 105 
poison in blood, effect on,.. 83 
tumefaction of, 272 
waste, elimination of, 82 
of cold-blooded animals. 110 
white appearance of, 273 
Tobacco, effect on iris 190 
Tone, high pitch of, 219 
pitch, dependence on, 219 
determination of, 197 
vibrations (musical), limit of,. 213 
requirements for, 216 
voice production of, 217 
Tongue, coated, effect of, 177 
dry, effect of, 177 
muscles, regulated by, 137 
nerve of,.. 178, 182, 186 
paralysis of, 186 
taste, diminished 183 
nerve of, 177, 181* 
qualities of, 182 
Tonsils, nerve of, 181 
Touch, an external sense, 163 
cerebral centre of, 169 
organs of, 145*, 146*, 224 
sense of, 145, 146 
different qualities of, 145 
modified by cuticle, 225 
most important 146 
sensation, diminished by ether 
spray 65 
by sedatives 65 
Trachea 101, 102* 
mucous membrane of, 40 
nerves of, 183 
structure of, 101, 102* 
Tragus of the ear 201 
Transitional epithelial cells 45* 
Transudation 301 
Traumatic 301 
Tremor of hands 133 
of head 209 
Trichina spiralis 269, 302 
i Tricuspid valve 90* 344 
INDEX. 
Trifacial nerve (See Nerve). 
Trigeminus nerve (See Nerve). 
Triple pregnancy 262 
Troehlearis nerve (See Nerve 
Trochlearis). 
Trophic centres 154 
nerve impulses 72 
True corpus luteum 256, 257 
mole 264, 266 
Tuber annulare 132 
Tuberculi acustici 180 
Tuberculosis, a cause of, 38, 39 
destruction in, 101 
temperature, symptom of, 122 
Tubuli lactiferi 262 
Tumefaction of tissue 272 
Tumor 271, 272 
defined 302 
pressure on bile ducts, result of, 65 
Tunica 302 
adventitia of arteries 95 
of veins 96 
albuginea ovarii 255, 256* 
testis 258* 
granulosa 259* 
intima of arteries 94 
of veins 96 
media of arteries 94 
of veins 96 
of eye 187, 188* 
of ovary 255, 256* 
Twelfth pair cranial nerves (See 
Nerve hypoglossal). 
Twin conception 266 
pregnancy 262 
Tympani, membrana, 201, 202* 
Tympanum 201*, 202*, 203 
mucous membrane of, 40 
Typhoid fever, blood in, 87 
diarrhoea in, 60 
dicrotic pulse in, 96 
intestinal effect of, 60 
Peyer’s glands, affected in, 59,60 
temperature of, 123 
Tyrotoxicon ..274, 302 
Tyson’s glands 228 
Ulcer 302 
Umbilical arteries 265* 
cord ligated, jaundice from, 65, 261 
vein 265* 
Unconsciousness in kidney disease 239 
Unipolar cell-process 138* 
Unstriated muscles 241 
Unstriped muscular fibres...243*, 249 
Urea 36, 37, 237 
absorbed, effect of, 238 
an amide of carbonic acid 237 
an excrementitious substance. 238 
artificially produced 237 
complete formation of, 238 
crystallized 237* 
Urea, diminished 37, 238 
Urea elements retained, effect of, 236 
excretion of, 36 
amount of, 37, 237 
increase of, 37, 238 
origin of, 36 
quantity of, 37 
Ureters .233, 234* 
mucous membrane of, 41 
muscular fibres of, 246 
Urethra, mucous membrane of,.. 41 
Uric acid 37, 238 
crystals of, 239* 
excretion, amount of,.. .37, 237 
of urine 238 
origin of, 37 
quantity of 37, 237 
reaction of 238 
Urinary bladder (See Bladder). 
Urine 236 
abnormal, 237 
acid reaction of, 73 
. albumin in, 240 
alkalinity of, 238, 239 
ammoniacal, 237 
as such, not in blood 108 
blue paper test 238 
carbonic acid, elimination by,. 112 
color of, 36 
composition of, 236 
earthy phosphates of, 30, 239 
evacuation, centre for, 237 
excretion of, 30, 31, 237 
fermentation, cause of, 237 
high specific gravity, symptom 67 
incontinence of , 239 
lime phosphate held in solution 30 
micturition, stimulus of, 237 
non-absorption of, 37 
passage of, 237 
precipitate in, 30 
quantity of, 236 
retention of, 239 
secretion of 71, 74, 235, 236 
increased 113 
solids of, 36, 238 
increased in, 113 
specific gravity of, 236 
sugar in,, 67 
suppressed, effect of, 236 
urea of (See Urea). 
Uriniferous tubules 233, 234, 235* 
carbonic acid gas secretion 
by, 109 
Urochrom, an albuminoid 34, 36 
property of, 36 
Uterus 251, 252*, 253* 
anteversion of, 280 
before puberty 252 
blood supply to, 254, 255 
cavity of, 252* 
cervix of, 252* Uterus, covering of, 254 
discharge from, 265 
epithelial cells of, 252 
lymphatics of, 253, 255 
mucous membrane of,..39, 41, 252* 
muscular fibres of, 246, 250 
neck of, 252* 
nerves of, 255 
secretion by, 253 
structure of, 251, 252* 
sympathy with stomach 141 
wall of, 252* 
Utricle of ear 202*, 207, 208* 
Vaccine lymph, parasitic life in,. 82 
poison, not detectable in blood 82 
virus, retained in blood 83 
Vagina 252*, 253* 
fornix of, 254 
mucous membrane of, 41, 42 
mucus, acid reaction of, 73 
Vagus nerve (See Nerve Pneumo- 
gastric). 
Valve or valves, auriculo-ventric- 
ular (See Valves Tricuspid 
and Mitral). 
coronary, 89, 90 
Eustachian 90 
ileo-ciecal or ileo-colic, 46,47,290 
in left ventricle 90 
in right ventricle 90 
mitral, 90* 
of aorta 90* 
of isthmus 46 
of lymphatics 77 
of pulmonary artery 90* 
of Thebesius (foramina) ... 90 
of veins 97* 
of Vieussens 132 
pulmonary (See Valve Semi- 
lunar). 
semilunar (aortic) 90* 
(pulmonary artery) 90* 
tricuspid, 90* 
Valvulse conniventes 59* 
Varnishing the skin, effect of,.... 112 
Vas aberrans 258* 
deferens 258* 
Vasa efferentia 258* 
recta 258* 
Vascular system, origin of, 260 
Vaso-con strictor impul ses 72 
Vaso-dilator centre 135, 302 
impulses 72 
nerve-fibres 72, 73 
Vaso-inhibitory impulses 72 
Vaso-motor centre 135, 303 
impulses 72 
nerve-fibres, function of,... 72 
reflexes 162 
Vaso-secretory impulses 72 
Vaso-trophic impulses 72 
INDEX. 
345 
Vater, corpuscle of, (Pacinian body). 
Vegetable albumen 27 
decay, a cause of, 36 
digestibility of, 49 
food as nourishment 32 
its principal constituent 27 
necessity of, 27, 32 
functions of, 23 
growth 23, 36 
life, action depends on organs. 23 
nutriment for, 23 
(See Plants). 
Vein or veins, blood changes in,.. 
81, 90, 100, 104*, 105 
capillaries of, absorpiton by, 
5o, / o, / 6, 98 
function of, 75, 76 
defined 88 
function of, 96 
gastric, 62, 63* 
hepatic, 63*, 97 
function of, 64, 76 
origin of, 63 
inferior mesenteric 62 
innominate, left, 76* 
right, 76* 
jugular, left internal, 76* 
right internal, 76* 
movement of blood in,.. .96, 97 
plexuses 96 
portal... 62, 63*, 76, 96, 97 
arterial function of, 96 
function of, 62, 63 
origin of, 62 
termination of, 63 
pulmonary 
90*, 98, 97, 102*, 104*, 105 
arterial function of, 96 
renal, 97, 234*, 235* 
splenic, 62, 63* 
fibrin in, 70 
structure of, 96 
subclavian, left, 76* 
right, 76* 
superior mesenteric, 62 
umbilical 96, 265* 
arterial function of, 96 
valves of, 97* 
velocity of blood in, 97 
without valves 97 
Velocity of blood stream 83 
Vena cava, inferior, 63*, 90*, 96 
superior, 76*, 90*, 96, 97 
innominata, left, 76* 
right, 76* 
porta 62, 63*, 76, 96, 97 
Venae cavse, blood velocity in,.... 83 
comites 96 
Venesection 303 
effect of, 70 
Venous blood, changes of, 
81, 90, 100, 104*, 105 346 
INDEX. 
Venous blood, current, variation of, 82 
difference in, 100 
flow, cause of, 97 
(See Blood). 
syf i, capacity of,.. 97 
tei rature of, 73, 119 
vai nation of, 100 
vessels, regulation of, 72 
Ventricle or ventricles, fifth,126, 127* 
fourth, .126, 127* 
lateral, 127* 
of the brain 127* 
of the heart 90* 
sixth, 127* 
third, 126, 127* 
Veratrin, action on ceils 65 
Vermiform appendix 47* 
Vertebrae, cervical, 151* 
coccygeal, 151* 
dorsal, 151* 
lumbar, 151* 
mobility of, 151 
sacral, 151* 
Vertigo 209, 210 
from ear cerumen 201 
Vesicles of Baer 255 
of evolution 258 
of Purkinje 256 
Vesico-spinal centre 155 
Vesicular mole 264 
murmur in lungs 106 
Vestibule of ear..201*, 202*, 206, 208* 
fluid of, 208 
nerve-fibres of, 180 
otoconia of, 207, 208* 
otoliths of, 207, 208* 
(See Ear, Internal). 
Vibration of sound, defined 213 
amplitude of sound 213 
period of sound 213 
Vieussens, valve of, 132 
Villus or villi 57*, 58*. 59* 
absorption by, 40, 57 
blood-vessels of, 57* 
chorionic, 261 
epithelial layer of, 57*, 58* 
function of, 58 
lacteals of, 57* 
nourished by; 60 
number of, 58 
structure of, 57*, 58*, 59* 
Virile power, centre for, 155 
Vis viva 120 
Vision, cerebral area of, 169, 173* 
dark spots of, 196 
double 175, 198 
from defect of nerve 178 
fovea centralis 196 
illusion of, \ 169 
(See Sight). 
Visual centre 173 
Vital bodies, function of, 23 
chemical combinations, guid- 
ance in 248 
economy, changes in, 248 
energy 249 
functions, influence on, 80, 121 
heat produced 114, 118 
organic representation.139, 165,168 
phenomena performed by cells. 24 
temperature effect on,.... 121 
point 92, 103, 138 
power of the body 93 
principle 94, 166 
power of, 248 
stimulation 94 
propagation flrst noticeable.... 25 
representation 168 
tissue-acid 41, 51, 248 
Vitality above chemism 109 
depends on, 23, 24 
impaired, a cause of, 106 
Vitelline membrane.. .256*, 259*, 303 
Vitellus 256, -303 
Vitreous body, or humor 187, 188* 
Vocal chords 218* 
length, importance of, 219 
muscular action on, 217 
separation, limit in voice... 220 
tension of 217 
vibrations of, 219 
Vocalization 220 
effect on larynx 218 
Voice, a voluntary act 217 
change of, at puberty 219 
chest tones 219 
co-operation in production of,. 137 
deep bass, 219 
falsetto, 219 
harsh and deep, from paralysis 218 
limits of, 219, 220 
loss of, from paralysis 218 
muscles required in production 
of, 217, 218* 
organs, nerves of, 183, 185 
pitch of, 213, 215 
production of, 217, 220 
nerves required for, 220 
range of, 219 
(See Speech and Sound). 
tones of, 220 
Volition, organic reflex of, 92, 93 
Voluntary impulse, tract of, 130* 
nervous action, on body, 93 
reflex only 92, 93 
motor apparatus, origin of,.... 260 
muscles. 246 
Vomiting, bile, a cause of,.. .55, 65, 66 
from tasting 182 
in pregnancy 141, 264 
nerve of, 184 
reflex action of, 182 INDEX. 
347 
Waller’s law 153 
Warm-blooded animals 110, 228 
Waste matter, quantity in blood.. 81 
Water, absorption of,. 77 
by skin 55, 231 
by vegetables 23 
amount of, required daily 30 
and albumen, coagulation of.... 27 
and sulphuric acid, heat from,. 120 
animalcula 269, 280 
diamagnetic properties of, Ill 
effect on red blood-corpuscles. 79 
elimination of, 30, 108 
by skin 30, 108, 123, 228 
from lungs 30. 108, 123 
essential in plants 23, 24, 36 
importance of, in body 29 
in blood 81 
perspired, amount of, 228 
proximate principle 26 
quantity in body 30 
repellent properties of, Ill 
Watery stools 77 
Weight of body, daily loss of, 231 
Wheat, bread from, 32 
nutriment of, 32 
starch in, 49 
White blood-corpuscles, 81 
affinity of, 87 
amoeboid movements of, 81 
motion of, 79 
number of, 81 
increase of, 84 
origin of, 56, 80, 81 
passage through walls of 
vessels. 81 
White blood-corpuscles (See Blood). 
size of,.... •. 81 
White blood disease 84 
fibrous connective tissue. 270 
of egg (See Albumen), 
substance of Schwann. i43, 144* 
swelling of tissue :i .272, 273 
tendinous connective tissue... 270 
Will, power over reflexes 141 
Willis, circle of, . 128* 
Winking of eye, suspended 193 
Wolffian bodies 239 
Womb (See Uterus). 
Woorara, action of, .‘148 
Work of muscles 248 
of heart 90 
World, organic, involves 23 
Worms in intestines 269 
Writing in aphasia, but unable to 
read it aloud 221 
Xanthogenate of potassium, ac- 
tion of, 53 
on albumen 53 
on peptones 53 
Yelk of ovum 256*, 259* 
membrane of, 256* 
Yellow elastic tissue 303 
fibrous connective tissue 270 
spot of eye 191 
of ovary 257 
Zona pellucidaof ovum, 255,256*, 259* 
Zone of Zinn 303 
Zymosis 303