Principles of Hygiene 
FOR 
THE SCHOOL AND THE HOME 
TOGETHER WITH 
SO MUCH OF ANATOMY AND PHYSIOLOGY AS IS 
NECESSARY TO THE CORRECT TEACHING 
OF THE SUBJECT 
BY 
EZRA M. A.M., M. D., Sc. D. 
TENTH PRESIDENT OF THE AMERICAN PUBLIC HEALTH ASSOCIATION, SECRE- 
TARY OF THE STATE BOARD OF HEALTH OF NEW JERSEY, AND 
INSTRUCTOR IN HYGIENE IN THE NEW JERSEY 
STATE NORMAL SCHOOL 
Copyright, 1886, by 
IVISON, BLAKEMAN, TAYLOR, AND COMPANY 
NEW YORK AND CHICAGO PRESS OF 
HENRY H. CLARK 8c CO., 
BOSTON, MASS. PREFACE. 
The design of this book is to furnish a Manual of Hygiene 
for use as a school text-book, and one that will be of service 
to all those who would acquaint themselves with the prin- 
ciples and practice of right living. When the study of the 
physical man was first rn-ged upon the attention of educators, 
it was with the special view of an acquaintance with Anatomy 
and Physiology. Hence most of the books which have been 
written cling to this title, and, while recognizing Hygiene as 
important, treat it as subsidiary. 
The author has been impressed with the view that, for 
the average scholar, a knowledge of Hygiene is far more im- 
portant than that of human structure and organs, and that 
the present courses of study justify the teaching of these 
to children only to the degree necessary for an intelligent 
practice of the health-preserving art. While this in- 
volves a valuable general knowledge of the human system 
and its functions, it also involves an equally important 
inquiry into our relations with our surroundings. 
It has been my design to furnish an outline which will 
acquaint the student with the scope of the study, and im- 
part information that will meet his practical and every-day 
needs. Por the teacher, I have desired to present a basis or 
nucleus for a much fuller presentation of details than can 
be included within the scope of a single volume. In my own 
teaching, I have always found it necessary to use far more 
than any one text-book contains, or ought to contain. Any 
teacher who will accept this as a guide, and avail himself 
3 4 
Preface. 
of tlie additional information to be derived from Physics, 
Chemistry, Geology, etc., and from the abundant literature 
of the subject, cannot fail to make the study of Hygiene 
as interesting as it is essential. 
I have not been obliged to use any human bones or objec- 
tionable plates in the school-room. The skeleton of a kid, 
and a few bones from the table, have answered every pur- 
pose. The relations of earth, air, water, foods, etc., are easily 
illustrated by experiments with ordinary school apparatus. 
While the author has not attempted to limit this book 
to the teaching of the injurious effects of stimulants and 
narcotics in the treatment of these subjects, in their proper 
connection, he has not failed to state the entire truth, and 
has been particular to give no doubtful views. It is believed 
that students will see that these subjects are treated be- 
cause the facts concerning them are unmistakable, and their 
connection with health inevitable, and that they will be 
impressed more by the facts thus presented than by any 
special pleading. 
In the preparation of this volume I have freely consulted 
all the most recent authorities, and I am especially indebted 
to the works of Huxley, Angell, and Newsholme. 
For many valuable suggestions, and for aid in press-read- 
ing and criticism, I am greatly indebted to the Hon. E. 0. 
Chapman, State Superintendent of Public Instruction of 
New Jersey. 
EZRA M. HUNT. 
Trenton, N. J., October, 1886. TABLE OF CONTENTS. 
CHAPTER I. 
INTRODUCTORY OUTLINE OF THE SUBJECT. 
PAGE 
Hygiene : Its Relation to Cognate Sciences and Arts; the 
Scope of the Study, and the Reasons for teaching it . 13 
CHAPTER II. 
THE EARTH AS RELATED TO HUMAN HEALTH. 
Its Constituents; Animals; Vegetables; Minerals; Soil; 
Air; Water; Heat; their Relations and their Effects 
on Health 24 
CHAPTER III. 
WATER IN ITS RELATION TO HEALTH. 
Its Sources without and within the Body; Air and Gases 
in Water; Animal, Vegetable, and Mineral Matters; 
Organic Impurities; Sewage; Parasites in Water; Re- 
lation to Disease; Rain-wTater for Drinking Purposes; 
Cisterns; Surface Water; Springs; Shallow Wells; Deep 
Wells; Bored or Tube Wells; Reservoirs; Tests of the 
Purity of Water; How to sink Wells; Lead-pipe; Filters 
and Filtering; Hardness of Water; Aerated Waters; 
Ice-water 34 
5 6 
Contents. 
CHAPTER IV. 
AIR, LIGHT, SUN HEAT, AND CLIMATE, AS RELATED TO HEALTH. 
PAGE 
Oxygen, Nitrogen, and Carbonic Acid; Aqueous Vapor; 
Purity of Air; Amount Needed; Air without Draught; 
Moisture of Air; Light and Sun-rays; Sun-baths; Elec- 
tricity ; Temperature; Climate and Health; Houses and 
Clothing as adjustments to surroundings 63 
CHAPTER V. 
THE ANATOMY OF THE HUMAN BODY, AND ITS HYGIENIC CARE. 
The Bones and their Uses; their Proper Nutriment; Protec- 
tion from Distortion and Accident; Effects of Posture 
and Pressure; the Chest; the Foot; the Effect of 
Habits; Deformities 80 
CHAPTER VI. 
THE MUSCLES.—BODILY EXERCISE. - CALISTHENICS. 
Athletics; Gymnastics; Calisthenics; Tendons and Liga- 
ments; Exercise; Body-building; Work; Walking; 
Bathing; Modes and Apparatus of Exercise 94 
CHAPTER VII. 
THE SKIN, ITS FUNCTIONS AND ITS CARE. 
The Skin: Its Functions and Care; its Vessels; its Nerves; 
its Glands; its Structure. Perspiration; Water; Other 
Excretions; Oil-glands and Hair-follicles; Papillae of the 
Skin; its Nerve Distribution; the Nails; the Care of the 
Skin; Bathing; Soaping; Rubbing; the various Baths; 
Special function 109 Contents. 
7 
CHAPTER VIII. 
CLOTHING AND HABITATIONS AS BODILY PROTECTIONS. 
PAGE 
Our relations to Heat and Temperature; Design of Clothing; 
Effect of Density; Fineness of Thread, Color, etc.; 
Elasticity of Fiber; Head coverings; Body coverings; 
Feet Coverings; Waterproof Clothing; Bed Clothing. 
Habitations : To be valued as Clothing. How made so as to 
adjust to our surroundings; as to Air; Temperature; 
Dampness; Dust; Protection from Chilling Draught . . 130 
CHAPTER IX. 
THE BLOOD AND ITS CIRCULATION. 
The Heart and its Tubes; its Mode of Action; Course of the 
Blood; Composition of the Blood; Effects of Alcohol 
upon it; the Capillary Circulation; the Lymphatics as 
related to the Blood; Circulation; the Spleen; Air, and 
Gases in the Blood; How it is replenished; Effects of 
Pressure on the Vessels; Hygiene of the Blood as to 
Food, Exercise, and Right Living; Faintness; Nose- 
Bleed; Care of Wounds or of Sudden Bleeding .... 147 
CHAPTER X. 
THE LUNGS, AND THEIR RELATION TO HEALTH. 
Their Capacity; their Bronchi and Air-cells; Formation of 
Carbonic Acid; Effect of Oxygen; Power of Blood to 
contain Oxygen; Impure Air; Air as a Food; the Act of 
Respiration; Clothing as Fitted to the Chest; Posture in 
Study; How to Breathe; the Voice and its Health; its 
Apparatus; How to Care for it; Conditions of Vocal 
Success 159 8 
Contents. 
CHAPTER XI. 
THE PROCESS OF DIGESTION. 
PAGE 
The Relations of the Mouth and Teeth; the Juices of Diges- 
tion; Mastication; Air in Food; the Order of Teeth; 
Sixth year Molars; the Care of the Teeth; Chyme and 
Chyle; the Successive Changes in the Digestive Process; 
Peristaltic Movement; the Liver and Pancreas; Effect of 
Stimulants on the Digestive Track; Deceptive Tolera- 
tion- 178 
CHAPTER XII. 
OUR FOODS AND THEIR USES. 
Their Relation to the Constituency of the Body; Nitrogenous 
Foods; Carbonaceous Foods; Mineral Foods; Require- 
ments of the Body as to each; Contents of Meats, Vege- 
tables, and Fruit; Tables showing Proportions; Milk, 
Bread, Eggs, etc.; Cooking of Foods; Starches; Green 
Vegetables; Potatoes; Principles of Cooking as applied 
to various Foods; Modes of preparing Bread; Hygiene 
of Digestion 196 
CHAPTER XIII. 
OUR DRINKS, AND EFFECT OF STIMULANTS. 
Water; Tea; Coffee and Cocoa; Oil in Cocoa; Chocolate; 
Alcoholic Beverages; Fermented and Distilled Liquors ; 
varieties of each; Intoxication denotes a toxic; Daily 
Rations of Soldiers and Sailors; Records of Registrar- 
General of England; Testimony of Scottish Amicable 
Life Assurance Society. Contents. 
9 
PAGE 
Effects on Particular Organs : The Teachings of Hygiene 
Explicit as to their evil effects; Condiments; Comparison 
of them; Tobacco and its Effects; the Cigarette . . . . 225 
CHAPTER XIV. 
MODES OF HEATING. 
Radiation; Conduction; Convection; Heating of inside air 
by Fireplaces, Stoves, Radiators, Pipes, etc.; Heating of 
outside air and introduction by Registers; Heating by 
outside Radiators and Pipes, and Introduction of Air 
thus warmed; Illustrations of all these; Comparison of 
them; Consumption of Oxygen; Other Modes of prepar- 
ing Air; Avoidance of Draught; of Dust; Chimneys; 
Cowls 246 
CHAPTER XV. 
VENTILATION OF HOUSES. 
Constituency of Air; Fire and Lights in Rooms; Living 
Beings; Minute Particles; Dryness of Air; Draught 
Windows; Air Space; Natural and Artificial Ventilation; 
Plenum and Vacuum Methods; Where shall Fresh Air 
be Introduced ? Outline of Regulations; Ventilation by 
Flues • Modes of Lighting; Gas Lights; Electricity . . 2C5 
CHAPTER XVI. 
THE SCHOOL AND ITS APPOINTMENTS. 
The Grounds; the Building; Drainage; Materials; Damp 
Course; Entries and Stairs; Doors and Ceilings; Floor 
Space and Area; Window Space and Light; Black- 10 
Contents. 
PAGE 
boards; Desks; Height of Seats; Care of Floors and 
of Walls; Janitorship; Care of Children; of the Skin; 
the Breath; the Throat; the Eyes; of Contagious Dis- 
eases 289 
CHAPTER XVII. 
WHAT TO DO WITH REFUSE, OR CAST-OFF MATERIAL. 
Conditions of Life; Decomposition; Methods of Disposal; 
Cremation; Use of Water Evils of Filth-Storage; 
Absence of Light and Air and Conditions favorable to 
Disease; Effect of Varying Ground Water or Decom- 
posable Matter; Personal Cleanliness and Perfect House- 
keeping ; How to Prevent Foul Accumulations; How to 
Deal with Decomposing Matter; various Disinfectants 
and Modes of Use 298 
CHAPTER XVIII. 
THE NERVOUS SYSTEM. 
The Cerebro-Spinal System; the Sympathetic System; the 
Relations of each; Description of the Brain and Spinal 
Cord, and of the Nerves as Distributed through the Sys- 
tem; Reflex Action; the Nervous Systems; Education; 
How we Educate ourselves into Reflex Actions properly 
or improperly; How we make acts habitual or auto- 
matic, and so are trained; Nervous Diseases; Alcohol in 
its Effects on the Nervous System; Effects of Narcotics; 
Recreation and Rest; how to Invigorate; Twitching, 
Sobbing, Spasm to be Heeded; Discipline in the Train- 
ing of the Nervous System; Body as well as Mind need 
Education; Wholeness of Being to be developed .... 307 Contents. 
11 
CHAPTEE XIX. 
THE SENSES. 
PAGE 
Sensations ; the Muscular Sense; how the Senses are Delated; 
Cultivation of the Senses; Sense of Touch; varieties in 
it; Comparative as to Localities; Training of the Touch; 
Handiwork a part of Education; the Taste; how Touch 
and Smell modify it; how it can be blunted; Perverted 
Tastes; the Sense of Smell; its Close Eelation to the 
Brain; the Olfactory Distribution; Effect of Foul Air in 
Sleep; the Apparatus for Hearing; the External, the 
Middle, and the Internal Ear; how we may effect Hear- 
ing ; the Throat; Hygiene of the Ear; Injuries, and how 
to guard against them 328 
CHAPTEE XX. 
THE SENSE OF VISION. 
The Protections to the Eye; its Secretions; how we may 
Disturb them; Affections of the Lids and Glands; the 
Structure of the Eye; its Delations to Light; its Chief 
Affections; Myopia; Hypermetropia; Astigmatism; their 
Causes; Eules as to their Avoidance; Specimens of 
Type; Artificial Lights; how the Eye is Injured; General 
Directions as to its Care; Color Blindness 350 HYGIENE. 
Chapter I. 
INTRODUCTORY OUTLINE OF THE SUBJECT. 
r ■ THE design of this manual is to teach the science 
X and the art of Health. Science is the exhibition 
of the actual relations of facts and principles and their 
bearing upon one another. It is not a mere knowl- 
edge of facts, but is the result of their classification and 
relationship. It is such an interpretation of facts having 
an ascertained, natural relation to each other as enables 
us to deduce from them laws. If there are such fixed 
laws which determine whether we shall be in good health 
or poor health, or have short or long lives, and if we 
can ascertain these laws, we can have a science as to the 
physical constitution and welfare of man as definite as 
we have about the physical constitution of the earth. If 
so, there is a science of Health. It is called Hygiology. 
2. Art is the application of the facts and principles of 
science,—a system which admits of the employment of 
distinct methods and rules. It is applied science. Some- 
times the application or practice precedes a knowledge 
of the science. If so, it is afterwards found to be in ac- 
cord with classified facts and with certain laws. If in 
13 14 
Hygiene. 
accord with definite rules we are able to preserve health 
and to prolong life, we each have an art to practice which 
has as its income and reward great personal benefits. It 
is the art of Health. It is named Hygiene. 
This term is derived from a Greek word meaning To 
be in good health. 
3. In ancient times the Greeks had a temple, dedicated 
to a goddess called Hygiea, at which votive offerings were 
made in order to secure health. In more modern times 
there have been those who have looked upon sickness as 
in such a sense a providential dispensation as to carry 
it out of the sphere of physical law into that of special 
infliction. But the more we come to know of variations 
from a condition of health, the more do we find them to 
be the providential penalty of broken law on the part of 
ourselves or of our ancestors. The more, also, do we find 
as to the possibilities of bettering our own health and 
that of others, by finding out just what the laws of nature 
and the applications of art indicate, and then conforming 
to these indications. The tendency to spring back to the 
condition of health is so strongly implanted by God in 
the human constitution, that it long ago led Hippocrates 
to speak of the vis medicatrix natures, or the restorative 
force of nature. 
4. The name of physician is derived from the Greek 
word <f)t(jtg, meaning nature, because the care of the 
human life and health was accounted to be the first and 
most important study of nature. Strange to say, the 
physical sciences for a time seemed to ignore man’s 
place in nature, and astronomy, geology, botany, and 
other studies of external nature seemed to claim a higher 
place than the study of the nature of man. Yet this Introductory Outline of the Subject. 
15 
study is more vital to his welfare than any other, and 
is excelled by none other in the wonders of science and 
the possibilities of art which it unfolds. In its breadth 
it includes all that is meant by right living, since the 
physical, intellectual, and moral natures are so united as 
to be very interdependent. While we now have to do 
primarily with the physical and material substance, and 
the laws of its structure and functions, we cannot lose 
sight of this unity. Since man is a part of nature, and 
since he is himself a complex piece of mechanism with 
various organs and functions, it is necessary to define a 
few terms which relate to him and to his surroundings. 
5. A study of life in its extent, and as applicable to all 
living things, is known as the science of Biology, or a 
knowledge of the Laws of Being. So far as it has to do 
with human structure, it is called the science or study of 
Human Anatomy. A knowledge of this comes only from 
a minute examination and description of all the parts 
that make up the structure. It also includes an inquiry 
into the laws of structure. To different parts of this study 
different names are given. 
So far as it has to do with function, or with the mode 
in which our structure or organs operate, it is called 
Human Physiology. A knowledge of this comes in part 
from a study of structure, in part from experiment, and 
still more from observation and experience as to how 
these functions are performed, and the conditions which 
in any wise aid, modify, or embarrass them. 
6. The science and the art of Hygiene consist in know- 
ing how best to secure the intended exercise of function, 
to furnish such aids as nature indicates, and to prevent 
such embarrassments as tend to permanent impairment. 16 
Hygiene. 
It is also called Sanitary Science, or tlie art of Sanitation, 
from tlie Latin word for soundness. As an engineer may 
operate an engine without knowing all the details of its 
construction, or without knowing all that there is to be 
known about steam, so success in the art of Hygiene, or 
in teaching or practicing it, does not necessitate a com- 
plete knowledge of all the organs and the functions of 
the whole body. 
7. While some knowledge of each of these is essential, 
and is to be sought in any attempt to acquire a knowledge 
of Hygiene, it is possible to know very much of both of 
these branches of study, without any valuable, practical 
acquaintance with the art of securing or preserving health. 
While for their special study every argument can be 
adduced that applies to the study of physical nature in 
the world about us, for our purposes they are related 
studies, to be pursued only to the degree which is essential 
to an intelligent appreciation and application of the art 
of securing health. 
8. We are, also, to bear in mind that to this study 
there are other cognate sciences, some acquaintance with 
which is necessary in the practical application of the prin- 
ciples of Hygiene. Thus some knowledge of Pathology, or 
the condition and action of parts or organs in a state of 
disease, often throws much light on normal function and 
the modes of promoting it. 
As physical, mechanical, and chemical laws are in- 
volved in vital processes, some knowledge and apprecia- 
tion of these is necessary. Hence it is, that various facts 
that relate to matter, force, motion, heat, and all life, have 
the most intimate relation to our subject. While expe- 
rience has long furnished glimpses of the truth, it was Introductory Outline of the Subject. 
17 
impossible for Hygiene to have a scientific basis, and to 
be taught and practiced as an art, until various physical 
sciences had made progress. As it now is, we are able to 
secure aid from all these, and to deduce laws which have 
a direct bearing on the appreciation and prolongation of 
life and the avoidance of disease. 
It is thus found that Hygiene is an aggregation of 
valuable parts of various sciences which bear much on 
life. It is a mosaic, all the more valuable because formed 
of so many parts, since they admit of exquisite adaptation 
and adjustment to the art of preserving life. Thus me- 
chanics, chemistry, geology, botany, and various other 
physical sciences, are constantly furnishing additions to 
this science and art. 
9. Nor has it to do with the physical sciences alone. 
Taking the word Hygiene in the largest sense, it sig- 
nifies rules for perfect culture of mind and body. It is 
impossible to dissociate the two. The body is affected by 
every mental and moral action; the mind is profoundly 
influenced by bodily conditions. While we do not need 
to confound the material and the spiritual, we do need 
to recognize their relations, and that there are laws of 
healthy action which apply to each. The body becomes 
the soil into which the mind and the spirit are implanted, 
and from which, if properly exercised, they must draw 
much of the source of their power in this world. Hence, 
even Psychology, or a description of the operations of the 
mind, on the basis of careful and classified observation, is 
in some of its aspects not foreign to our inquiry. So it 
has been claimed that the knowledge of the philosopher 
in all his departments has an intimate bearing on this 
care of life. The pioneer of modern Hygiene entitled his 18 
Hygiene. 
first work the Philosophy of Health, and in it treated of 
all these departments. As philosophy is an inquiry into 
facts and principles and an attempt to weigh or appre- 
ciate their real value, and as there is no value superior 
to that of perfect health for body, mind, and soul, the 
term was rightly applied. Hence in our own language, 
health is not only the generic term of wealth, welfare, 
etc., but its possession is the fullest conception of earthly 
bliss. 
10. In its study we can constantly perceive, in the har- 
monious proportions and complete balance of all parts, 
the evidence of the designing skill of one great Creator. 
Even amid the disorder which has only resulted from 
disobedience of law, we cannot but admire the wonderful 
reparative processes and the constant struggle which this 
physical structure seems to make to resume its original 
perfectness. As we examine into the exquisite adaptation 
of the thousands of parts of the body to each other, we 
can no more conceive of the absence of a maker than 
we can conceive of thousands of types falling into words 
and sentences without a presiding and designing power. 
11. As we behold the reign of law, and the uniformity 
of result, if the laws of health and life are obeyed, we are 
able to see that the vast amount of suffering and inca- 
pacity in the world is the result of breach of law for 
which ignorance and sin are alone responsible. As we 
see how reparative and conservative of health this won- 
derful organism is, how self-regulating and self-repairing it 
is, if only we approach to conformity to its laws of being, 
we come to admire the wondrous mechanism and plan, 
and gain courage in the effort to make our lives what 
they should be. There is a confidence of success, when Introductory Outline of the Subject. 
19 
we learn that these laws of life and health are ascertain- 
able, and that in conformity thereto results for our own 
enjoyment and usefulness are as certain as in any of the 
laws relative to the physical world about us. 
12. Such progress has been made in our knowledge 
of the laws of life, that Parkes has well said that “ it is 
undoubtedly true that we can even now literally choose 
between health and disease, — not perhaps always indi- 
vidually, for the sins of our fathers may be visited upon 
us, or the customs of our life and the chains of our civili- 
zation and social customs may gall us, or even our fellow- 
men may deny us health, or the knowledge which leads 
to health. But, even with these embarrassments, it is 
remarkable how far we can improve or correct these con- 
ditions, and how much we may profit individually by 
the knowledge and practice of the laws of our being.” 
13. Because this practice needs to begin very early in 
life, because habits formed are so likely to become fixed, 
and because knowledge and impressions early received 
are the most lasting, the study of Hygiene ought not to 
be left for mature life. It needs to form a part of the 
home and school instruction and training. What we 
would have appear in individual and social and natural 
life we must have appear in the home and in the school; 
especially when it has to do with our growth and devel- 
opment, and when the knowledge is needed as much in 
early life as it is afterward. It is essential, in order that 
full development may be secured and a general condi- 
tion of health maintained. 
This acquaintance with the sanitary demands of our 
natures, and with the modes of securing for the body 
what its construction and functions require, enables us 20 
Hygiene. 
to avoid many errors, and to give to it the advantages to 
which it is entitled. 
14. Here are some of the reasons for the study, and 
for the early study, of Hygiene, which can be enlarged 
upon and illustrated by the teacher, or by any one 
who will consider the subject in its intimate bearing 
upon life. 
(a) Good health is intimately related to our success 
and happiness in life. The impediments and limita- 
tions which sickness or partial invalidity impose, and 
the anxiety and unrest they occasion, are too often well 
known. 
(b) Education is physical, intellectual, and moral. 
Any attempt to deal exclusively with the development 
of one part of our nature without the other is as wrong 
in practice as it is in theory. 
(c) Knowledge of how to care for and develop the 
physical power is no more natural than much of our 
knowledge as to mind or morals. Teaching and training 
are as essential in the one as in the other. 
(d) Habit teaching in all its varieties is very much 
the intent and the accomplishment of education. This, 
at first, is mainly made up of physical acts, the mind itself 
receiving its impressions through physical methods. All 
through life the acquirement of physical habits is the 
key of self-control, self-reliance, and to that educational 
attainment which helps to ability and character. 
(e) In physical teaching and training very much is 
accomplished for discipline, for method, for observation, 
experiment, memory, and thought. 
(/) Man’s place in nature is larger than that of any 
other one thing in it. A study of him is a study of Introductory Outline of the Subject. 
21 
nature and of one of the natural sciences and the mode 
of teaching it. 
(g) There is much training of the moral nature in 
physical education. Behavior is having the being in 
possession and under control, and the knowing how to 
handle one’s self as a whole. Obedience to the knowl- 
edge so acquired is an element alike of character, conduct, 
and power. 
(h) It aids the teacher much in his own preparation 
for his work and in his discipline. 
(i) We are constantly seeing the evils of that kind of 
education which concentrates too much on mere men- 
tal development. Consult Froebel, Horace Mann, Canon 
Kingsley, etc. 
(j) The need of it has become largely recognized else- 
where. We have examples in Sweden, France, and 
England, and in some of our own states and cities. 
15. This study naturally divides itself into five depart- 
ments. 
I. There must be such a knowledge of the structure 
and functions of the human body as will enable us to 
know what are the conditions of its normal being, or 
what it requires. By a study, for instance, of bones and 
of muscles, of the lungs and their mode of action, or of 
the digestive apparatus, we cannot fail to arrive at some 
correct conclusion as to how they are to be used and as 
to the relations of exercise, of air, and of foods thereto. 
II. As the human system derives its supplies from 
without, and is dependent upon its surroundings, we need 
to know precisely what these supplies are, and what sur- 
roundings are conducive to health, as well as to know 
what are hazardous thereto or positively injurious. 22 
Hygiene. 
Thus our relations to the earth, to the air, to water, to 
foods, to heat and light and moisture, to odors, to sensa- 
tions and impressions made on the senses, — indeed, to 
most of external nature, — is such that we have carefully 
to consider how these favorably or unfavorably affect 
human life. 
III. When we find actual defects, the practical appli- 
cation of Hygiene often requires that we should know 
how to adapt our methods to the defects so as to secure 
a return to the normal conditions, and cause complete re- 
covery. Here our effort is not merely to make up for the 
defect, but so to deal with it as by gradual improvement 
to remove it. Both physical and mental hygiene are 
sometimes able, by pliable and gradual methods, to secure 
return of health, where the abrupt application of the laws 
of health, as applicable to perfect functions, would pro- 
duce only disease. Thus a weakened muscle may not 
need such exercise as that muscle at such an age ought 
to be able to endure, but such as is suited to its reduced 
capacity, and so arranged as to restore it to its proper 
strength. 
IV. Since, when we find defects in our construction or 
functions, and defects in our environment or surround- 
ings which have a bearing on our well-being, we cannot 
always be rid of them, we often need to inquire by what 
methods adjustments are to be made and such compen- 
sation secured as will reduce the evil to a minimum. 
Thus houses and clothing and fires serve to adjust us 
to the outside world in some respects. If the upper teeth 
are gone, we may not only fulfil an indication as to 
digestion by an artificial set, but help to preserve those 
in the lower jaw by providing a co-operating set. Introductory Outline of the Subject. 
23 
V. In addition to these we need to have a correct view 
of our social and corporate relations as members of com- 
munity and of the obligations we are under to preserve 
our own health and that of our neighbors. Hence it is 
proper to speak of personal hygiene as having to do 
with (a) our personal health, as it relates to ourselves; 
(6) our personal health, as it relates to the welfare of 
our neighbor; and (c) public health, as it relates to 
the family, the school, the municipality, the state, or the 
nation. 
While all these divisions cannot be fully treated in 
such a manual as this, it is desirable to recognize the 
breadth of the study, as thus we are likely to be more 
eager in its pursuit, and to prepare for more extended 
insight. Since we more readily see a,nd understand 
nature as it surrounds us, than as it is within us, it will 
be the more convenient order to consider first our sur- 
roundings, as they are related to our health. Chapter II. 
THE EARTH AS RELATED TO HUMAN HEALTH. 
AS the earth is by nature fitted for the habitation of 
man, we expect to find it adapted thereto, just as 
we find the air suited for breathing. Yet the earth, 
like the air, has undergone very many changes, and may 
not now in every place and under every circumstance be 
suited for human dwelling. It is just as sensible to talk 
of changing ground as of changing air for health. 
2. The ground may have become so submerged by 
water, or so filled with it quite up to the surface, as to 
make it too damp or wet for a being not meant to be 
aquatic. It may have become so shut out from the sun 
as not to be able to dispose of that amount of water 
near the surface which, under natural circumstances, it is 
advantageous to have circulating or evaporating there. 
The soil or ground nearest the surface may be so over- 
charged with decaying or putrescible matter, that none 
of the usual processes of nature can dispose of it, and so 
there will be a pollution of the adjacent air, earth, or 
water. If so, it becomes unfriendly to man’s physical 
welfare. 
3. The ground or earth represents at least five con- 
stituents, all of which are related to health. It has its 
inorganic or mineral constituents, which may exist in the 
form of rock or be mingled with the softer materials of 
ground. These are such as fire will not consume. Many 
24 The Eabtii as related to Health. 
25 
of these are entirely harmless, or useful as ores, or as 
giving solidity to the earth’s surface, while others, if they 
become diffused in fine particles through the air, or come 
to be dissolved and suspended in water, have an influence 
upon health. Thus finely pulverized dust may be irritat- 
ing, or the water, as in limestone regions, may become im- 
pregnated with lime so as to produce hard water, which 
as a rule is not as healthful as the softer water. Some 
of these inorganic constituents, like the ore of arsenic, are 
directly poisonous. 
4. Next, the earth has both living and dead matter in 
various forms of animal and vegetable life. This, so long 
as it is alive, or so long as, in its processes of growth and 
decay, it is being appropriated by animals or plants to 
which it is suited, is not injurious. But so soon as there 
is such accumulation as is not thus appropriated, or 
such as is beyond the ordinary demands of vegetation, or 
where it is gathered with no growing vegetation to con- 
sume it, it becomes a menace to health, and must be 
studied in its relation thereto. The very richness of 
ground, which is so favorable to most plants, is likely 
to be hurtful to human life, if the soil is exposed to the 
heat of the sun, and has no chance to give up its riches 
to the plant-life for which it was intended. 
5. Next, the ground contains air or the constituents 
of air. Air is intended to circulate in the upper ground 
as well as above it. It is by its free circulation that the 
ground disposes of various organic and decayable matters 
in it, and allows these to be taken up by animals or by 
growing plants. All the multitudes of little spaces be- 
tween the particles of ground are filled up either by water 
or by air, which alternately circulate in it. If you fill 26 
Hygiene. 
a cup with soil, you may yet pour into it considerable 
water, which, as we say, soaks into the ground. This 
merely means that it occupies the spaces between the 
particles of earth which just before had been filled 
with air. 
While there are some other gaseous substances to be 
found in the ground besides the nitrogen and the oxygen 
which form common air, these are but small compared 
with the vast amount of air which the ground contains. 
It is often from thirty to fifty per cent, and in loose 
surface soil may even equal its own volume. This ca- 
pacity of the ground for air is also a measure of its capa- 
city to contain the various gaseous products of decompo- 
sition, which may be set free, and which not only make 
foul the ground, but the air also. If ground is polluted, 
foul gases in part take the place of pure ground-air. 
Health and life greatly depend upon the fact that air 
or water are not stagnant in the ground just beneath 
us, but are constantly circulating and conducting those 
changes which are favorable both to animal and vege- 
table life. It is one of the evils of wet ground, that it 
expels the air, and so prevents evaporation and circula- 
tion as to keep the ground soaked. This prevents those 
changes in organic or decayable substances which are 
necessary to enable them to be taken up by grains, vege- 
tables, and grasses. So we are to remember that air be- 
longs in the ground. In its circulation, it is meant to 
oxidize and hydrocarbonize animal and vegetable decay, 
so as to make it innocuous, and furnish great volumes 
of carbonic acid to vegetable life. 
6. Water, as we have already incidentally seen, has 
a very important relation to the earth. It is not only The Earth as related to Health. 
27 
that the earth is to be the receptacle of the water as it 
comes from the clouds, which, by its percolation through 
the soil, carries on various processes. There is a depth, 
varying with soil and locality, at which the ground water 
is intended to fill up the spaces between the earth par- 
ticles. It can thus be drawn upon for the supply of the 
earth vegetation, or by reason of its relation to strata 
and water-sheds it flows out upon the surface in ponds, 
lakes, and rivers, and is accessible by means of wells, 
so as to furnish drink to man and to beast. When it is 
stagnant too near the surface, it aids to convert organic 
matter into peat; but when it is found as a kind of per- 
manent reservoir far beneath the surface, it is there 
stored for use, only subject to slight fluctuation, and kept 
in better condition than by any storage art of man. We 
shall in another chapter consider it as a drink. Suffice 
it here to refer to (a) its important relation as a part of the 
earth in deciding as to conditions of decay, (6) in affecting 
temperature by its evaporation, and (c) in the dampness 
and ill-health it so often produces when stagnant or too 
constantly abounding near the surface. 
The chief design of drainage in its health-relations is 
to secure for the upper ground free circulation both of air 
and of water, and to drain off water from the soil. 
7. We next note that the sun and temperature have 
much to do with the ground. It is intended to have its 
alternations of heat and of cold. The sun causes in the 
earth a diurnal wave of heat, in our climate, of about four 
feet in depth, varied somewhat by soils and seasons. As 
this recedes by night there is circulation of heat beneath 
the surface; the line of uniformity of temperature is from 
fifty-seven to ninety-nine feet below the surface. Ground GEOLOGICAL SECTION. —The Different Formations and their Equivalent Soils. 
Post Tertiary. 
Alluvial Soils. 
Oak Land Soils. 
Pine Land Soils. 
Tertiary. 
' Cretaceous. 
Upper Marl Bed. 
Middle Marl Bed. 
Lower Marl Bed. 
Clay Marl. 
Clay and Sand Soils. 
Red Sandstone. 
Shale and Trap Soils. 
Mesozoic. 
Jurassic. 
Triassic. 
Caboxiferous. 
Permian. 
Sandstone and Shale Soils. 
Limestone Soils. 
Clays. 
Sandstone Soils. 
Limestone Soils. 
Coal-Measures. 
Sub-Carboniferous. 
Devonian. 
Old Red Sandstone. 
Limestone Soils. 
Slaty Soils. 
Limestone. 
Sandstone. 
Conglomerate Soils. 
Upper Silurian. 
Lower Silurian. 
Slate. 
Limestone. 
Sandstone Soils. 
Archsean. 
Gneissic Soils. The Eabtli as belated to Health. 
29 
may be kept so continuously cold as to be made damp 
thereby, or so continuously and excessively hot as that 
the decaying material in it is forced into rapidity of 
change incompatible with the health of human beings. 
The ancients termed fire, air, earth, and water the ele- 
ments. Each and all are in the ground beneath us, and 
have much to do with health. 
It is worthy of note how the lower animals come to 
know the differences of ground conditions, and to choose 
for rest spots where the ground is dry and airy. These 
are cases in which the instincts of animals are wiser than 
the thoughtlessness and ignorance of men. 
8. The earth differs much in all the respects we have 
mentioned according to its geological formation, its ele- 
vation, its latitude and longitude, its plains or forests, 
and other variations made by constitution, locality, or 
plant-growth. All these make or affect the climate. 
The wide variety there is in geological formation and 
arrangement needs to be studied and to some degree 
understood by the sanitarian. These do much in deter- 
mining the relations of air, water, heat, and decomposi- 
tion to the ground and to those upon it. A tenacious 
clay near the surface has made many a locality water- 
bearing and unhealthy, when the removal of a few feet 
deeper down would have given a gravel foundation and 
an extended drainage. The map on the opposite page 
will serve to show how many different strata there may 
be. They admit of all varieties of arrangement. 
It is, however, with the soil, or the earth within a few 
feet of the surface, that we have especially to deal when 
we speak of the earth as related to health. Soil is derived 
from the rock from which the substratum is composed, 30 
Hygiene. 
mingled with animal and vegetable matter. It crumbles 
into sand, clay, gravel, etc. So we come to speak of 
clayey, gravelly, and sandy soils. When there is an 
abundance of organic matter mingled with it or deposited 
upon it, as where successive forests have fallen upon 
it, we call it a loam. Where the soil is largely made up 
from such decay, or the overflow from such deposits, it 
is known as alluvial soil. 
Some soils, instead of being mostly made up of the 
broken-up rock or strata beneath them, have been formed 
by drifts or deposits of earth, stones, and loose material, 
which by winds, rains, and the force of great freshets 
of moving water or ice have images past been dislodged 
and deposited in valleys, or where they have been caught 
by some barrier. 
9. Between air and water and heat there is a cor- 
relation and conservation which is as wonderful below 
ground as above it. The surface, like the human skin, 
is but the plane of contact, while within is incessant 
motion. This condition of relations is necessary for the 
carrying forward of changes which, when uninterrupted, 
tend healthward, but which, when suspended, contami- 
nate the ground. There is a vis medicatrix naturae in 
the earth as well as in man, which is dependent upon the 
uninterrupted play of natural forces. The effect of stag- 
nant water is to cause the decomposed vegetable and 
animal matter in the soil to accumulate. The conditions 
of temperature of air and of liquids are self-regulating to 
a surprising degree, when art does not intervene. But 
to this end there must be air and heat and water circulation. 
Even those myriad organisms, from bacteria upward, 
which science is revealing, are instituted methods for The Earth as related to Health. 
31 
disposing of organic material; but it is only amid the 
activities of air and water circulation that their action 
is manifested. The capacity of the ground for air is 
readily shown by expelling the air from dried earth. In 
other words, by pouring into it water we find its capacity 
for air. Such ground as we are familiar with varies much 
as to its porosity or dryness; and even marble will hold 
four per cent of water. 
10. The sanitarian is not slow to make inquiry about 
soil, if he is seeking to determine where is the best place 
to live. He knows that a tenacious, clay soil is not likely 
to be healthful, unless it can be so drained at the sides 
or so cut through down into a gravel as to make it 
dry and more porous. He does not, because a pond is 
unsightly and a house will cover it, drain off a pond 
and build a house over it. He knows that the causes 
which made the pond there, and the long accumulation of 
organic matter about it, are unfavorable to health. If all 
his land is like that of a AVestern prairie, where the muck 
or alluvial deposit is many feet deep, he seeks to know 
how far it is to gravel or sand, or how he can drain and 
improve the soil, or compensate for its too great richness, 
by other aids to its healthfulness. He would, for instance, 
see that close to his house the land was heavily cropped 
each year, and that ashes and lime were added to it in the 
cropping rather than any organic compost. He would not 
shade it with trees as he would if building on a light 
gravelly soil exposed to the sun. 
11. It is a rule as to all soils desirable for dwellings, 
school-houses, or factories, that the level of the ground 
water should be at least three feet below the bottom 
of the cellar, and that it should not be so affected by 32 
Hygiene. 
heavy rains as to be subject to rapid or frequent rising. 
This means a soil where drainage is good, or where air 
and water and warmth get into the upper soil from above 
the surface. We not only want to be rid of the water, 
but equally to have the ground filled with pure air. If 
the well is near the house, its depth and the rise and fall 
of its water give indication of the general water level, 
unless there is some abrupt change of soil near the house. 
12. Where the water is too near the surface much can 
be done by thorough systems of drainage which are now 
well understood. The building of cellar-walls with hard 
brick laid in cement, and with the wall cemented on its 
back surface, with upright spaces between the layers, and 
with a cement floor, adds much to the dryness. In addi- 
tion, a course of slate or asphalt or other impervious 
material is sometimes laid upon the brick just above the 
surface of the ground. This is called a damp course, and 
is intended to prevent the passage of dampness from the 
cellar-wall to the walls of the building. Perforated brick 
and terra-cotta are used for the same purpose, as allow- 
ing evaporation, and so securing dryness as well as a 
material of different compactness. Impure ground-water 
is often sucked up from one brick to another so as to 
reach the walls of rooms. Chills and fever, colds, con- 
sumption, rheumatism, neuralgia, and other ailments are 
certainly often traceable to living on too damp earth, or 
in dwellings that partake of this dampness. 
13. Women, who live more in the house than men, 
are especially liable to suffer in health from cellar or 
house dampness. Whole districts of country have had 
their sickness-rates and death-rates sensibly and perma- 
nently diminished by systems of drainage. Many cities The Saute as related to Health. 
33 
need systems of drainage as much as they do systems 
of sewerage. Even in the putting down of sewers, one of 
the incidental benefits is that the lines of these sewers 
break through the layers of soil and provide drain- 
courses through the ground. Subsoil drainage and sur- 
face drainage are needed for many soils, if buildings are 
to be erected on them. Every home and every school- 
house needs to be studied in its relation to the earth 
around it. Chapter III. 
WATER IN ITS RELATION TO HEALTH. 
WE have had occasion to refer to water in the chap- 
ter on Earth, since it forms so large a portion 
of the globe on which we live. It is not only that the 
rivers, the seas, and the ocean form so large a part of it: 
it abounds also in the soil, and, hidden beneath various 
strata, it comes to the surface in springs or is sought for 
by means of wells. 
1. Leaving the consideration of its relation to all veg- 
etation and to all varieties of lower animal life, we have 
still greater occasion to consider it as a drink, and as 
related to the life and health of mankind. It forms so 
large a portion of the body, that in a person weigh- 
ing one hundred and forty pounds about one hundred 
pounds is water. So we have had the modest definition, 
that man is made up of a little solid material dissolved 
in six pailfuls of water. Of the blood, water constitutes 
eighty parts, and of the solid tissue, about seventy-five. 
Of all the secretions it is the chief component, so far 
as actual quantity is concerned. 
2, Our bodies, on an average, part with over two 
quarts, or sixty-four ounces, of water each day; and with 
much more under violent exertion. Of this amount full 
eighteen ounces passes off through the skin and about 
nine ounces through the lungs. Thus water is the great 
distributer of all materials introduced into the system, 
34 Water in its Delation to Health. 
35 
and the conveyance by which much of the used-up 
material passes away from it. While it cannot be said to 
be a food, in the usual sense, yet it may to some extent he 
appropriated as nourishment. In extreme cases of lack 
of food, it serves to bring into use the materials within the 
system which may, by any possibility, be made available 
for nutrition. By its evaporation, it equalizes the tem- 
perature of the body and assists in chemical changes. 
3. All the water used in the body is not derived from 
what is generally called potable or drinking water. It 
forms a part of grains that are usually spoken of as dry. 
It abounds in meats, vegetables, and fruits. We reckon 
about thirty-eight per cent of it in bread, seventy per cent 
in lean meat, from seventy to ninety per cent in vegeta- 
bles, and even more in some fruits. Indeed, if we used all 
these in a natural state, there would not be need of very 
much additional supply. The supply we do need we de- 
rive from the earth or from the sky. The great inquiry is 
how to secure it in the purest and most acceptable form. 
4. As a chemical substance, water consists of two parts 
of hydrogen and one of oxygen by volume, or one part of 
hydrogen and eight parts of oxygen by weight. It is 
capable of containing much air between its particles, and 
in its natural state always contains it. Because of this 
some kinds of fish do not need to come to the surface of 
the water to get their supply of air. A gallon of water 
at 62° F. weighs ten pounds; at the boiling-point, with 
the air expelled, it weighs nine and one-lialf pounds. 
When air is taken into the stomach unmixed, it some- 
times causes much disturbance, while that which gets 
there mixed with the water or the food is an important 
aid to digestion. 36 
Hygiene. 
Twenty-five gallons of water contains in its air about 
five parts of the oxygen and nitrogen of which ordinary 
air is composed. But while five parts of ordinary air 
contain nearly four parts of nitrogen and one of oxygen, 
five parts of the air of water will contain about three parts 
of nitrogen and two of oxygen. 
5. Well aerated water holds in solution about two 
cubic inches of oxygen and six of nitrogen per gallon. 
Twenty-five gallons of ordinary lake water contains from 
a quarter to a half pint of carbonic acid gas. River 
water often contains to every twenty-five gallons one 
gallon of carbonic acid gas in solution, because the 
chemistry of nature has been busy in disposing of the 
carbonaceous or decayable matter in it. Where water in 
city wells, for instance, is very sparkling, and almost 
inclined to effervesce, it is a suspicious circumstance ; for 
it shows how busy nature has been in appropriating the 
organic material, and that it may have failed to dispose 
of it entirely. Water that is exposed to air fouled with 
various gases will absorb them and hold them in solu- 
tion, when the water is stagnant and not abounding in 
oxygen. Thus water from graveyard wells may often 
be clear and sparkling, but if kept in a closed, half-filled 
bottle two or three days will emit odor. 
6. The best water for drinking or potable purposes is 
that which is mingled with pure air which is free from 
any organic animal or vegetable matter, either solid or 
gaseous, and which does not hold in suspension or solu- 
tion any mineral matter. Such ideal or chemically pure 
water is rarely if ever found; but with this as a standard, 
we can define those departures therefrom which are be- 
yond the bounds of safety. Water in its Relation to Health. 
37 
Water is frequently colored by vegetable matters, and 
yet the amount is such as to be easily neutralized or 
discharged from the system without evil effects. It is 
only when vegetable matter is in a state of decay that 
there is much risk. A good deal of it is disposed of in 
the ordinary processes of nature, but in very hot or dry 
weather becomes hazardous. The same is true as to 
animal matter, or excretions, which are in general more 
dangerous than vegetable matters. It is chiefly so when 
undergoing active putrefactive change, and especially 
when it contains those living vegetable micro-organisms 
which now are recognized as associated with disease. 
7. Much water is constantly being used which is con- 
taminated by sewerage or other organic impurities. It 
does not always do appreciable harm, because our systems 
are so constructed as to adjust themselves to a certain 
degree of irregularity, and to resist slight or ordinary 
embarrassments. There is also another reason. Nature, 
chiefly through the action of the air mingled through or 
dissolved in the water, is constantly transforming that part 
of the organic or decayable matter which is carbonaceous 
into carbonic acid gas, and the harmful nitrogenous mat- 
ter into insoluble nitre. Both of these, to the degree thus 
produced, are harmless. It is when this process is inter- 
rupted, or when the amount or kind of matter is such as 
not to admit of sufficient neutralization by these methods, 
that decomposable matters remain in the water, ready 
to act as fertilizers for forms of minute life so threatening 
to the higher life of man. The danger is, that in certain 
special conditions of atmosphere or temperature or local- 
ity, or of our own bodies, this organic matter will be 
roused into some peculiar or more rapid decomposition, 38 
Hygiene. 
and that some form of disease-breeding animal or plant 
life will, from it, obtain that abnormal cultivation which 
will excite disease. This may take the general form of 
irritation, such as will produce non-specific disease, or it 
may prove specific in its character, and we then have 
cholera, typhoid fever, or some other deadly plague. 
8. This brings us to notice the fact that, besides those 
defilements both of air and of water which are chemical 
in their nature, or have to do with foul gases, there is 
another source of danger which has come into great 
prominence in the last few years. It is found that both 
air and water abound with minute forms either of animal 
or vegetable life. To distinguish them from gaseous 
products, they are usually called “particulate,” as made 
up of particles. These are intended to be conservative 
of health and life, by feeding or nourishing upon those 
things not needed by man, and injurious to him. But 
when air and water are subjected to very abnormal con- 
ditions, and are continuously and extravagantly befouled, 
either these low forms of life multiply to an amount which 
nature cannot dispose of, or new and virulent forms 
spring up, which, getting into the system through air 
or water, give rise to specific forms of disease. This is 
known as the germ or parasitic theory of disease. These 
microbia or micro-organisms are oftener vegetable than 
animal, and are classified as are the lower forms of fungi 
in botany. The animal microbia are known as microzoa, 
and the vegetable as microphytes. Of the microphytes, we 
have various forms, as bacteria, bacilli, micrococci, and 
spirochsetse. These, implanting themselves on mucous 
membranes, and rapidly multiplying, are believed to 
cause fevers and various forms of communicable disease. Water in its Relation to Health. 
39 
They have been traced both in foul air and foul water, 
but most frequently in water. 
9. AVhile it may be said comparatively that very much 
impure water is used which does not cause disease, it is 
always hazardous. As with filth-laden soil, so with fouled 
water. The system puts up with it, and, although with 
some increased expenditure of vital force, may overcome 
their ill effects or may adjust itself to them. But too 
often the limit of endurance is reached. Under some special 
conditions, or because of what seems to us the accidental 
presence of some specific form of animal or plant life, this 
decayable matter is just the soil to fertilize and render 
noxious the floating particle, and we become the host for 
that quick and wonderful life of organized matter which 
results in disease or death. 
It is thus seen how impure waters do not always cause 
appreciable harm, and yet how at any time they may 
become the occasion of the most serious diseases. Very 
often, when no such results are recognized, the digestive 
system is disturbed, and the general vigor reduced. Many 
persons die from the diseases produced by impure water. 
10. The water that comes from the sky as rain-water 
has mingled with it much air, and is the purest natural 
water. In its descent it gathers a small amount of min- 
eral and organic matter, but this is likely to be much 
less than it finds in the ground. In cities, or where the 
smoke is dense, the water falling first is not so pure. 
While we would not give to rain-water storage undue 
prominence, there must ever be much reliance upon it. 
There will always be places where rain-water from roofs, 
or prepared impermeable surfaces, constitutes the only 
source of supply for separate dwellings. We therefore 40 
Hygiene. 
briefly outline the mode of its collection and preser- 
vation. 
11. Potable rain-water is best collected on slate roofs. 
The leader should always be so arranged as that the 
first rain can wash off the roof and not discharge into 
the cistern. Two or three automatic arrangements are 
used for this purpose. This prevents any fouling from 
the dust of roofs, from leaves, or from the “ cellulose or 
weather-beat” of shingle roofs. If a leader ends in a 
hogshead or tank proportioned in size to the roof, it can 
receive the first washing, and, when full nearly to the 
top, an overflow into the permanent cistern will carry off 
the pure, incoming stream, and leave the former to be 
used for non-drinking purposes. It is best, also, to have 
the mouth of the leader, as it leaves the roof, protected 
by a copper gauze, or a galvanized wire covering, so as 
to prevent any lodgment of leaves. 
12. Whether the cistern shall be near the roof, in some 
upper room, or whether it shall be in the ground, will 
depend much upon convenience and locality. If near 
the roof, it should be well built, preferably in a circular 
form, or if square and lined, should have such lining as 
will not furnish lead or copper or too much iron to the 
water. The overflow should be so arranged as not, when 
its pipe is empty, to be an open tube to convey foul gases 
to the water. It therefore should not enter into the gen- 
eral soil-pipe. The cistern, while constructed so as to be 
accessible for cleansing, and while generally needing a 
covering, should not be so made as to confine stagnant 
air over the water. 
13. When a cistern is placed in the ground, it should 
be deep enough to keep cool in summer and not to Water in its Relation to Health 
41 
freeze in winter, or to be cracked by the action of the 
frost. As the weight of water is ten pounds to the gallon, 
the receptacle for any large amount needs to be made 
strong. Cast-iron tanks, properly painted or dipped, after 
the Angus Smith method, are now often used. The capa- 
city of the cistern should be ample, as it is best to store 
the water of long rains rather than that of occasional 
summer showers. The reason for this is that the first 
rain-water washes out the impurities in the air and upon 
roofs. If we reckon the average rainfall at thirty 
inches, or seventeen gallons a square foot, and allow a 
loss of six inches for the first water and short rains, and 
six inches for evaporation, there could be had from a 
roof of three hundred and sixty square feet, available for 
storage, five hundred and forty cubic feet of water, or 
three thousand three hundred and seventy-five gallons 
in the year, which, for the house, would be an average 
daily supply of nine gallons. 
14. We next come to that supply of water which is de- 
rived from the surface of the ground. Although originally 
from above, it is variously deposited or retained in the 
earth. That which is found in lakes and streams is gen- 
erally known as the surface water-supply. It is that for 
which nature has its own reservoirs, on the surface of the 
earth, in lakes and streams, which receive the drainage of 
water-sheds more or less extended. Sometimes, this is 
spoken of as of two kinds, namely, the surface-water from 
uncultivated or sterile lands, and that from cultivated 
lands, since the kind of soil through which the water flows 
furnishes it more or less with the organic matters which 
it contains, as well as with mineral ingredients. If the 
organic matter is so superabundant as not to be dimin- 42 
Hygiene. 
ished by filtration through the soil, or oxidized by ex- 
posure to the air, it makes the water impure, while if 
limestone or other crumbling rocks abound, the character 
of the water is modified by these. Special plants may 
also give a peculiar odor to water, or, when in very great 
abundance, may add to it much decaying material. This 
water has the advantage that being on the surface it is 
exposed to air and sunlight, and by its motion over rock 
and pebbly bottoms is constantly aerated. How real is 
this advantage is sometimes illustrated by the freezing of 
rivers which are somewhat impure. Then, because of the 
exclusion of the air, the water, which in the summer 
was not complained of, in winter becomes scarcely lit 
for use. The disadvantage of such exposed sources of 
water is that they are subject to various artificial sources 
of pollution from cities, factories, dwellings, and soil en- 
richment. 
15. The next surface-supply is that from springs. These 
are governed in position and depth by that of the dif- 
ferent layers of the earth structure. Water, finding its 
way to an impervious bed, forms rivulets along that bed, 
and a water-level is there maintained. The direction 
of the slope, or dip of the slope, or a sudden change in 
the formation, causes the water to appear on the sur- 
face as a spring. If these are not deep they represent 
surface water of recent percolation through soil, and 
often rise and fall according to the abundance or lack 
of rain. 
16. Next, is the water-supply derived from shallow wells. 
These wells are those which are fed by land or surface 
drainage. Though some of them are spoken of as deep, 
unless their depth is over twenty-five feet, “ they depend Water in its Relation to Health. 
43 
directly for their water upon the area immediately sur- 
rounding them, the rain-water falling upon which sinks 
downward and laterally toward the bottom of the well. 
The quantity procurable may be likened to the contents 
of a cone, the base of which is the area around the well, 
and its apex the bottom of the well, the contents being 
renewed from time to time as the rain falls. The extent 
of this area, or base of the inverted cone, is the greater 
the more porous the ground is for any given depth of 
well.” 
Such is the water on which, in the absence of public 
supply, most communities depend. By passage through 
the ground strata, and by this filtration and oxidation, it 
is usually pure, unless in its course it has derived con- 
tamination beyond the power of the natural forces in 
operation in the ground and air to neutralize. Not only 
are some soils, such as gravel and sand, more porous 
than others, but rocks also differ in porosity. Thus the 
new red sandstone is so porous as to act as a filter, and 
often removes much organic matter. Some kinds of rock 
contain organic matter. 
Again we have the deep well, which represents what is 
sometimes called the resident water, or the more constant, 
deep water-level which is beyond the seasonal influence 
of drought or storm. To this class belong deep-dug wells, 
driven and bored wells, when deep, and artesian wells. 
17. Of all these classes, it may be said, in general, that 
supplies nearest the surface may be very excellent, if only 
in the upper soil and surroundings there is no super- 
abundance of organic matter. They even have the ad- 
vantage of the more active and continuous presence of 
air for oxidation purposes. Their risk is, that pollution 44 
Hygiene. 
of the adjacent lands or soils about them is more easily 
received by them than by the deeper reservoirs. 
18. As to each of these we single out the more im- 
portant suggestions and precautions. First, as to river 
and lake supply. Whether this shall be relied upon 
will depend upon the purity of the source, the character 
of the country through which it flows, the possibility 
of preserving it free from contamination such as would 
add to it decomposable organic matter, or such min- 
eral matter as is harmful, or such taste either from 
mineral or vegetable sources as would give discomfort. 
If any such matters are added, the question also arises 
as to how far these are self-correcting in the flow and 
exposure of the stream, and what means can be used 
to prevent or neutralize the impurity. Also, as a test 
of actual condition, we need the repeated examinations of 
chemists, and the testimony of close medical observers, 
who, by actual statistics of sickness and death, and close 
observation and analysis of cases, will be able to give 
opinions which can serve as guides. Where, owing to 
appreciable and temporary causes, there may be contami- 
nation, or cloudiness, or discoloration, or taste, it is to be 
considered whether filter-beds or other methods may not 
avail for cleansing. Thus, even the taste and smell from 
water-plants, such as the nostochia3 species, are greatly 
improved by proper filtration. 
19. The character and conditions of the reservoirs need 
to be carefully examined, both as to cleanliness and as to 
what is best for the agitation or aeration or protection 
from heat of the impounded water. For it is known that 
reservoir water is not always so pure as the source from 
which it comes. There are often no comparisons of con- Water in its Relation to Health. 
45 
ditions and strange neglects of examination. We not 
infrequently find reservoirs that have not been cleansed 
for years, or properly investigated to know whether they 
are in need of cleansing, with gates or oflier wood-work or 
appendages in an improper condition, and with adjacent 
soil contamination by reason of added pollutions. Wher- 
ever a city is supplied with water by a company, it is 
especially important that knowledge as to these matters 
be sought. The service-pipes, too, are sometimes found 
in an improper condition, and those having intermittent 
supply may need aeration. The growths and deposits on 
these have sometimes been such as to affect water. If 
the joints are calked with organic material, as hemp, etc., 
the water is sometimes polluted and unpleasant to the 
taste. The plant-life of reservoirs and pipes sometimes 
needs microscopical examination. 
20. Whether a river shall be used as the natural 
drainage for the adjacent territory, or whether it shall 
be practically the water-carriage for sewage, or whether 
it shall be the source of water-supply, is often a difficult 
and always a relative question. In a region where the 
rain-fall is large, and so many other sources of supply 
are available, rivers should not be resorted to where 
water can be obtained from series of wells, gravel-bed or 
other water-bearing strata, or impounded in reservoirs 
depending upon a supply high up amid uncultivated 
and comparatively uninhabited hills. This is accom- 
plished by arresting the flow of the streams at a point 
high up in their course, where forests abound, or where 
there are few inhabitants. Upland surface-water from 
uncultivated grounds, which, after percolating through 
the soil, can be gathered either from springs or wells, or 46 
Hygiene. 
from a kind of elongated well in the shape of a res- 
ervoir, on the edge of a hill, or so as to intercept a 
water-bearing strata, is by all acknowledged to be a 
most reliable source of supply, so far as the quality of 
water is concerned. 
The average rain-fall of the country must, with due 
allowance, be taken into consideration, together with the 
amount of water likely to be needed. The general rain- 
fall is forty to forty-four inches. One inch of rain falling 
on a square foot gives rather more than half a gallon, so 
that forty-four inches of rain-fall a year represents a little 
over twenty-two gallons for each square foot. 
There needs to be a careful study of the natural water- 
shed, its underlying strata, its extent, what its loss is by 
rapid flow from the surface, by sun-heat and evaporation, 
and by any artificial interruption or addition thereto. 
21. As to springs, although they generally represent 
water that has been filtered through higher ground and 
has reached a water-holding strata, it is to be remem- 
bered that springs thus open need careful protection from 
impurities, that they may be too highly charged with min- 
eral ingredients, and that they may become affected by 
the pollution of the soil in their immediate vicinity. 
22. Shallow wells are but elongated drainage-tubes laid 
perpendicularly instead of horizontally, and so, just as 
much as a field-drain, gather in the adjacent water. If 
the ground for a hundred feet or more around them has 
little organic matter in it, if it bears grass or other herb- 
age to dispose of any organic matter in it, or if there is 
gravel or sand which forms a good filter for the descend- 
ing rains, such water may be very good. But it is easy 
to see that wells that are not over ten or fifteen feet in Water in its Relation to Health. 
47 
depth are liable to many possible contaminations. There- 
fore both the ground about them, and the sides and cov- 
ering of the well, need to be protected from any sources 
of organic or decayable matter. Besides contamination 
from the soil above, or from carelessness about the cover- 
ing or the apparatus used for drawing the water, the 
roots of trees near by, or the decay of the wood-curb that 
has been used in bricking or stoning up the well, may 
cause impurity of the water. 
This diagram will serve to show how easily such wells 
may become contaminated from the surface. 
Scale 30 feet to the inch. 
FIG. II.—Showing different strata of soil and gravel. 
23. Deep wells are generally safer, because they repre- 
sent water-bearing strata out of the reach of surface 
contamination. They are openings into the pure reser- 
voirs that are not much affected by what happens on 48 
Hygiene. 
the surface of the ground. They give access to a purified 
residual water, which has a constancy of quantity and 
quality, and which, in long passage through the ground, 
has been thoroughly percolated. To this there are a few 
exceptions, by reason of the character of strata or local 
deposit. Such water also, by reason of the mineral charac- 
ter of the geological structure through which it has passed, 
or on which it rests, may have a mineral impregnation 
which gives it either valuable or disturbing mineral 
properties. Sometimes this deep water supply has such 
relation to hills or surrounding strata that it reaches the 
surface either through natural openings or through arti- 
ficial tubes. These latter constitute the true artesian wells. 
24. Bored or tube wells are merely the substitution of this 
form of access to the deep waters for the more usual form 
of dug wells. The tube well has the advantage over the 
ordinary deep well, in that the tube serves to shut out 
any organic matter from the surface which by reason of 
the artificial hole made from the surface might serve to 
let in organic matter from the upper soil. But even with 
these it sometimes happens that the upper ground does 
not pack closely about the pipe and that the outside of 
the pipe serves as a course or conduit by which foul sur- 
face or upper soil liquids may trickle down to the hidden 
well at the bottom of the pipe and be drawn up without 
much dilution. 
25. Tests of the Purity of Water. — Too much de- 
pendence must not be placed upon opinions as to the 
purity of water derived from the preferences of persons 
accustomed to its use. Water may have no taste that 
would be criticised, and may seem very refreshing to the 
thirsty one, even when dangerously impure. Then, too, Watee in its Relation to Health. 
49 
by use we become accustomed to a particular water, and 
may prefer it regardless of its real purity. It seems to 
be a part of human boastfulness to claim that one’s own 
well is the best in the neighborhood. Nor is it enough 
that no actual sickness has been traced thereto. It is 
marvellous how resistful some persons are to imperfect 
foods and drinks, and how the forces of a reserve energy 
of health either resist or compensate for depressing influ- 
ences. Yet there are others who are more affected, and 
all are making a wastage of resisting power that is more 
wisely and usefully expended in some other direction. 
There is often need of such examination of waters as 
can be made only by sanitary experts. The chemist, the 
physicist, and those accustomed to study and weigh all 
the facts which determine the purity of water, may need 
to be consulted where the evil threatens serious results. 
The following ready tests, as suggested by Prof. R. C. 
Kedzie, will serve to guide as to the quality of water. 
Color. Fill a large bottle made of colorless glass with 
the water; look through the water at some black object; 
the water should appear perfectly colorless and free from 
suspended matter. A muddy or turbid appearance indi- 
cates the presence of soluble organic matter or of solid 
matter in suspension. 
Odor. Empty out some of the water, leaving the bot- 
tle half full; cork up the bottle, and place it for a few 
hours in a warm place; shake up the water, remove the 
cork, and critically smell the air contained in the bottle. 
If it has any smell, and especially if the odor is in the 
least repulsive, the water should be rejected for domestic 
use. By heating the water to boiling, an odor is evolved 
sometimes that otherwise does not appear. 50 
Hygiene. 
Taste. Water fresh from the well is usually tasteless, 
even though it may contain a large amount of putres- 
cible organic matter. Water for domestic use should be 
perfectly tasteless, and remain so even after it has been 
warmed, since warming often develops a taste in water 
which is tasteless when cold. If the water, at any time, 
has a repulsive or even disagreeable taste, it should be 
rejected. 
26. Heisch’s test for sewage contamination. The delicacy 
of the sense of smell and of taste varies greatly in differ- 
ent individuals; one person may fail to detect the foul 
condition of a given water, which would be very evident 
to a person of a finer organization. But if the cause of a 
bad smell or taste exists in the water, the injurious effects 
on health will remain the same, whether recognized or 
not. Moreover, some waters of very dangerous quality 
will fail to give any indication by smell or taste. For 
these reasons I attach especial importance to Ileiscli’s test 
for sewage contamination, or the presence of putrescible 
organic matter. The test is so simple that any one can 
use it. Fill a clean pint bottle three-fourtlis full with the 
water to be tested, and dissolve in the water half a tea- 
spoonful of the purest sugar, loaf or granulated sugar 
will answer; cork the bottle and place it in a warm place 
for two days. If in from twenty-four to forty-eight hours 
the water becomes cloudy or milky, it is unfit for do- 
mestic use. If it remains perfectly clear, it is probably 
safe to use.” 
27. The chief tests used by chemists in determining the 
quality of potable water are known as the Chlorine test, 
the Ammonia or Wanklyn test, the Frankland or Com- 
bustion test, and the Biological or Koch test. Water in its Relation to Health. 
51 
In the Chlorine test, the amount of chlorides present 
in the water is determined, since chloride of sodium is a 
constant constituent of sewage, and the quantity in good 
water is very small. 
The Ammonia test is based on the fact that most nitro- 
genous, organic matter may be made to give off a part or 
the whole of its nitrogen as ammonia, and on the view 
that the nitrogenous, organic matter is the chief source 
of danger. The ammonia thus obtained is called “ albu- 
minoid ammonia.” 
In the Frankland or combustion process a given quan- 
tity of water is evaporated, and the residue is submitted 
to an organic analysis which converts the carbon into 
carbonic acid and liberates the nitrogen. The relative 
proportions of carbon and nitrogen indicate the character 
of the organic matter. 
The Biological method is the application of tests which 
determine the minute organisms in water, since impurity 
multiplies such animal and vegetable life therein as is 
believed to be often the efficient cause of disease. 
As all of these require expert tests, they are only re- 
ferred to here as showing how important to health such 
investigations are held to be, and how available they are. 
28. It is clear, from all that has been said, that in sink- 
ing wells the greatest care needs to be exercised in their 
construction and as to the apparatus used for drawing the 
water. The stone or brick work, called the steining, must 
be of such material as has in it no organic matter, and the 
earth packed behind it must contain no soil or decayable 
matter of any kind. If a curb has to be used, it must be 
of wood that does not impart taste to the water, and does 
not readily decay. For at least five or six feet from the 52 
Hygiene. 
surface the steining should be laid in cement, so as the 
better to keep out the upper surface-water. 
29. The apparatus for drawing must itself be free of 
anything that would contaminate the water. If it agitates 
the water in the drawing, fresh air is thus mingled with 
the water, as many claim with advantage. Among more 
recent devices for purifying water, especially in reservoirs, 
has been the introduction of compressed oxygen or com- 
pressed air into the water, in order that any organic 
matter it may contain may be more readily oxidized and 
thus neutralized. Many wells are injured by not having 
a covering which will prevent the entrance of any liquid 
or solid substance from the top. The top of the well 
should be a little higher than the surrounding ground, 
and there should be no careless rinsing of vessels about it. 
The water supply is in daily use, and should be guarded 
as we would guard health and life. 
30. Wells sometimes change in the quality of water. 
This may be owing to something having fallen into the 
well, to a seam in the adjacent or underlying rock which 
has become saturated with filth from some distance or 
serves as an inlet for some cesspool, or to some sudden 
discharge or pressure from a cemented vault or some 
other source. More frequently it happens that a cesspool 
or slop-pipe, or other foul source of organic matter, has 
for a long time allowed the soil not far off to become 
saturated. Boil, cool, and aerate suspicious drinking-water. 
31. Lead pipe, because of its convenience and pliability, 
is often used to bring water from wells or springs into 
houses. All waters contain more or less dissolved oxygen. 
This, combining with particles of the lead, may get into 
the system and cause that peculiar affection known as Water in its Relation to Health. 
53 
lead-poisoning, and so often taken at first to be rheumatic 
pain. Saline substances, sometimes present in waters, 
seem to increase this action of the oxygen on the lead. 
This is especially true of the ammoniacal salts, the 
nitrates and the nitrites. In some cases, the pipes become 
coated, so as to be protected from action where the water 
itself would otherwise produce it. So many and various 
have been the cases of digestive irritation, of wrist-drop, 
and of other affections of the system from lead-poisoning, 
that if lead be used, it is always recommended to run off 
from the pipes all water that has stood all day or all 
night in them, and not to use for drinking or cooking 
any water which has passed through the pipes when hot. 
New pipes are especially hazardous, and should be emptied 
frequently. Pipes from a public water supply are not as 
hazardous as those from wells or springs. Where a lead- 
pipe runs down to a well, and water is drawn through 
it by suction, the union of oxygen with the lead is often 
rapid, and instances of lead-poisoning from these are 
most frequent. Why some persons are so much more 
susceptible to lead-poisoning than others has not been 
explained. 
32. Filters and Filtration of Water.—Water that is 
cloudy in appearance or unpleasant in taste is some- 
times much improved by the use of a filter. This acts as 
a strainer to remove minute particles. By using materials 
which are not compact, but have spaces between the par- 
ticles for air, the water is brought into contact with it, and 
some oxidation of organic matter takes place. It is also 
claimed that in the use of some substances there is chemi- 
cal change, so that organic matter is neutralized and ren- 
dered harmless. While there is no evidence that specific 54 
Hygiene. 
particles, such, for instance, as give rise to typhoid fever, 
would be removed, the clarification and purifying of the 
water removes materials from which lower forms of life 
derive their pabulum. One objection to filters is, that 
if the impurities left behind in the filtering material are 
not occasionally washed out or removed, they remain to 
be decomposed. Yet filters act chemically as well as me- 
chanically, for they bring the oxygen and nitrogen of the 
air into closer contact with the divided particles of water, 
so that in place of the organic carbonaceous matter we 
get dissolved carbonic acid, and in place of the nitrogen- 
ous matter, a small quantity of harmless nitre. 
The great filter, as we have seen, is the earth through 
which the surface and rain water is passed to lower beds or 
strata, there to form the water-level in the ground, down 
to which we sink wells, or from which springs appear at 
hillsides or other points where there is change of strata. 
The perfection of this filtration depends much upon the 
character of the ground. If there are alternate layers 
of gravel and sand, or gravel only, the percolation or 
filtration is generally quite perfect. But if there is much 
organic matter in the soil, or mineral matter that can be 
dissolved, the water instead of being filtered is charged 
with it. 
33. Filtering is done on a large scale when large filter- 
ing-beds of sand, gravel, etc. are made in connection with 
reservoirs, so that the water can be filtered before it is 
distributed to houses. As generally constructed, they are 
water-tight basins with the sides built in masonry. The 
bottom is cemented, and piping or channel-ways are made 
upon it, so that the water after passing through the filter- 
beds may find easy access out. On the bottom layers Water in its Belation to Health. 
55 
broken stone is placed, and above it screened gravel 
of uniform size, and on this, one or two layers more of 
smaller size, the thickness of each being about three 
inches. Over all are two or three layers of sand arranged 
in similar manner. The water is let on from the reservoir 
so as to cover this filtering-bed a few inches in depth, and 
is allowed to flow through it at a regulated rapidity. 
Occasionally, the water is drawn off, so as to expose it 
to the air, and to cleanse it or replace the upper layers 
of sand. 
To obtain the best results, the filtering material should 
be frequently aerated. Air is a far better cleanser of a 
filter-bed than water. 
The idea, then, of a perfect filter is one which, by 
the mechanical arrangement of the parts of which it 
is composed, secures the most perfect mechanical separa- 
tion of every particle in suspension in the water; which, 
by adhesion to its surfaces or “ mechanical entanglement ” 
in its pores arrests these particles, and which also, by this 
arrangement, secures the most perfect facilities for the 
aeration of the water and oxidation of all organic matter 
in it. 
34. Cisterns are often well provided with filters of their 
own, by having a partition of brick, so that the water 
passes into one side and out through the other. A 
solid brick wall, laid carefully in cement mortar, makes 
a good filter. The bricks should be rather underburned, 
extending through from one side of the wall to the 
other, and the faces of the wall not covered with mortar. 
Water will filter through such a wall fast enough for the 
supply of a family, and if the rain all enters the cistern 
upon one side of the wall and is drawn out from the 56 
Hygiene. 
other side, the water is clean and sufficiently pure. Such 
cisterns should be occasionally cleaned out, and the par- 
tition wall scrubbed. If, by an ordinary bellows, air is 
blown through the brick septum from the side opposite 
to that on which the roof water comes in, it helps to 
restore its straining power. 
35. There are various forms of house-filters, some of 
which are cheap and valuable. Flannel tied on the faucet 
of the water-pipe will greatly improve the appearance of 
drinking-water, and will strain out much organic matter. 
A tube or box with sponge in it will also be satisfactory 
in clarifying turbid water, and it is easily and quickly 
washed and replaced. A sheet of filtering-paper, as used 
by druggists, in a glass or tin funnel, furnishes a good 
means of filtering water on a small scale. A fresh sheet 
of filtering-paper will be generally needed each day. 
Granulated, animal charcoal, in boxes or vessels where 
the water can filter slowly through it, improves its ap- 
pearance and quality. A common form of filter may 
be described as follows: — 
36. Take any common vessel perforated below, such as 
a flower-pot, and put a small, clean piece of sponge over 
the hole. Fill the lower portion with gravel-stones, over 
which place a layer of finer gravel, and on these a layer 
of clean, coarse sand, the proportion of each being about 
the same. On the top of this place a lid of unglazed clay, 
either very porous, or perforated with small holes, and on 
this a stratum, three or four inches thick, of well-burnt 
animal charcoal. A filter thus formed will last for a 
long time, is easily cleaned, and will be found to act both 
by mechanical and chemical purification. Water in its Relation to Health. 
57 
The following are good directions from so good an 
authority as Dr. Parkes: — 
“ Get a common earthenware garden flower-pot; cover the 
hole with a bit of zinc gauze or a bit of clean-washed flannel, 
which should be changed from time to time; then get some 
rather small gravel, wash it very well, and put it into the 
pot to the height of three inches; then get some white sand 
and wash it very clean, and put that on the gravel to the 
height of three inches; then take two pounds of animal char- 
coal, wash that also by putting it into an earthen vessel and 
pouring boiling water on it; then, when the charcoal has 
subsided, pour off the water, and put some more on for three 
or four times. When the charcoal has been well washed, 
put it on the sand and press it well down. Have four inches 
of charcoal, if possible. The filter is now ready. Pour 
water into the pot, and let it run through the hole into a 
large glass bottle. 
“ After a time the charcoal will get clogged; take off a 
little from the top and boil it two or three times, and then 
spread it out and let it dry before the fire. It will then be 
as good as ever. From time to time all the charcoal and the 
sand also may want washing. The sand may be put over 
the charcoal, and not between it and the gravel; but this 
plan sometimes leads to the charcoal being carried, with the 
water, through the gravel and out of the hole. The sand 
stops it. 
“ By filtering in this way, and by boiling the water, many 
dangers are done away with.” 
Another similar suggestion is as follows : Use a simple 
glazed earthenware jar, holding five gallons, or even 
less, having a double bottom. The upper bottom has 
a small hole, closed by a bit of sponge; the space of 58 
Hygiene. 
four inches or so between the two bottoms is packed with 
clean gravel, above which is fine, clean sand; the lower 
bottom is perforated with very fine holes, through which 
the water slowly passes to an earthenware vessel below, 
into the top of which the filtering vessel tightly fits. The 
water is drawn off from the lower vessel by a faucet. If 
this lower vessel is unglazed, it will serve at once as a 
cooler and reservoir. 
Charcoal has been objected to, because, if not occasion- 
ally changed or if impure, it attracts minute forms of 
animal life. This is not true of the fresh animal char- 
coal, which removes not only a large proportion of the 
organic matter in water, but also a not inconsiderable 
amount of mineral saline matters. 
37. The other chief filtering materials besides those 
named above are spongy iron, the magnetic carbide of 
iron, and silicated carbon. 
Spongy iron is prepared from the common hematite 
ore by fusion, and yields iron in a porous and granular 
condition. It is said by the Rivers Pollution Commis- 
sion of England to be a very active agent, not only in 
removing organic matter from water, but also in mate- 
rially reducing its hardness and otherwise altering its 
character. 
The magnetic carbide of iron, which is similarly used, 
is obtained by heating hematite with saw-dust. 
Silicated carbon consists of charcoal, silicon, and a little 
oxide of iron and alumina, and is highly recommended 
for filtration by Wanklyn. 
While too much reliance must not be placed on filters, 
yet they are often available means for correcting the taste 
and improving the general quality of the water. Even Water in its Relation to Health. 
59 
without the direct chemical effect claimed by some, they 
act as minute strainers, and by bringing air in contact 
with the water, oxidize that organic matter by which 
the lower forms of animal and vegetable life are sus- 
tained. Of the putrescible material, they at least remove 
much of the matter upon which the lower forms of animal 
and vegetable life are nourished, and so are of service. 
These filters require cleansing or the occasional re- 
newal of the filtering material. They should not be closed 
so as to keep water stagnant upon them, but may now 
and then be allowed to run dry, so as to refresh with air 
the spaces between particles. Where there is the least 
suspicion of well-water, boiling and aerating it by pouring 
from one pitcher to another is a good precaution. It is 
often well to consult the family physician, who may aid 
in the more simple tests; but if there is good reason 
for suspicion, he will advise you not wholly to rely upon 
these approximate results, but direct you to those who 
have more experience in the work, and the advantages 
of laboratories with all appliances needed. 
38. Hardness of Water. — Lime salts are the chief 
cause of hardness in water; compounds of magnesia, iron, 
and other elements, however, may contribute to that soap- 
destroying power of the water, which is practically meant 
by the term. Chemists recognize two kinds of hardness: 
(1) Temporary hardness, which is caused by the presence 
in the water of elements held in solution from which 
the carbonic acid can be separated by boiling. Thus 
the carbonic acid holding them in solution is driven out, 
and the precipitate this held then separates in the solid 
form, and can be removed by filtration. (2) Permanent 
hardness, which is caused by the above bases, which are 60 
Hygiene. 
in combinations not converted into the insoluble form 
by boiling, — sulphates, chlorides, etc., chiefly the first 
named. The temporary and permanent hardness together 
constitute the “ total hardness.” In general it is correct 
to say that hardness produced by earthy carbonates is 
“temporary hardness,” because it can be removed by 
boiling, while that produced by the earthy sulphates is 
permanent hardness because boiling does not remove it. 
The first is chiefly in the form of chalk and the latter 
of gypsum, — the former being a carbonate of calcium or 
carbonate of lime, and the latter a sulphate of lime. It 
is the former which is especially noticeable in some 
waters, which diminishes their value for culinary and 
manufacturing purposes, and which in some persons 
causes indigestion or inorganic deposits. In Glasgow 
it is estimated that the consumption of soap has been 
diminished one-half since the introduction of soft water. 
Every grain of chalk or calcium carbonate wastes eight 
or nine grains of soap. Not only does soft water need 
less soap, but it is much better for making tea and soups, 
or for boiling meats or vegetables. Those who have to 
use hard water for making tea often add a little soda in 
the pot so as to precipitate the lime. Boiling does tins 
somewhat, as is seen by the hard incrustation in kettles 
in which much hard water has been boiled. This not 
only makes more fuel necessary, but, as in the case of 
steam-boilers, weakens and injures the metal. As a unit 
standard, water is said to be hard when there is one grain 
of bicarbonate or sulphate of lime to a gallon of water. 
Ten grains of hardness is generally spoken of as the limit 
for culinary and drinking use, and even so much is not 
desirable. Water in its Relation to Health. 
61 
39. The hardness of water may be greatly diminished 
by what is known as the Clark process. The explanation 
of the process is as follows: Chalk, or carbonate of lime, 
becomes bicarbonate of lime when it is dissolved in water 
by carbonic acid. On adding lime, it unites chemically 
with the carbonic acid, which ordinary water contains, and 
forms chalk. The chalk formed, or the chalk originally 
present, having now no carbonic acid to hold it in solu- 
tion, is thrown out of solution and is slowly deposited. 
This removes the hardness which was caused by the bi- 
carbonate of lime. Milk of lime is the form in which the 
addition is generally made. Ordinary lime-water, kept in 
a stoppered bottle and added to hard water, will soften it. 
In the Porter, Clark, and Atkins processes the separated 
chalk or lime is at once filtered out through cloths. 
40. Aerated water is made by shaking good ordinary 
water with carbonic acid gas, in proper vessels, under 
pressure. The general name for it is soda-water, because 
the original effervescent fluid contained soda. True soda- 
water contains fifteen grains of bicarbonate of sodium 
to the half-pint, but the “ soda-water ” which is sold for 
drinking has simply been aerated with carbonic acid. 
It quenches thirst and slightly exhilarates. Ginger-beer 
and various other forms of drink are but aerated water, 
with some flavoring condiment. 
41. With the increasing evidence that water is often a 
conveyer of disease, and that frequently, by its impurities, 
it depresses the vitality of the system, it becomes the duty 
of every person to be familiar with the ordinary impuri- 
ties, and with some of the methods of their detection. So 
long as by the boiling of water, by aerating it, and by 
various other methods, we can protect ourselves from 
these risks of impurity, we should not fail to do so. 62 
Hygiene. 
42. There is need of some caution as to the use of ice 
and ice-water. By chilling the stomach, we may cause a 
sudden arrest of digestion. Ice is not so purified in the 
act of freezing but that it will partake of the character of 
the water from which it is formed. Minute worms have 
been taken alive from pond-ice some months after it has 
been frozen. Minute forms of fungoid or cryptogamic life 
are not destroyed by freezing. Outbreaks of disease have 
been traced to the use of impure ice. Chapter IV. 
AIR, LIGHT, SUN-HEAT, AND CLIMATE, AS RELATED 
TO HEALTH. 
IF earth and water are indispensable to human life, 
not less so is that gaseous mixture called air which 
pervades our globe, and which, when received into the 
lungs, accomplishes changes in the blood on which life 
directly depends. From 1,500 to 2,000 gallons of inspired 
air are each day received into the human system. A sin- 
gle inspiration of an adult takes into the lungs about 
thirty cubic inches. 
2. Pure or normal air consists of a mixture of the gases 
known as oxygen and nitrogen. The mixture is a me- 
chanical and not a chemical one, but the properties of the 
two gases vary somewhat. The oxygen is more soluble in 
water, and hence, as we have seen, is found in a larger 
proportion in water than in the open air. The oxygen 
and nitrogen of the air have the proportion, by volume, 
of 20.61 of oxygen to 77.95 of nitrogen, or, by weight, of 
23 parts of oxygen to 77 of nitrogen. The general state- 
ment is that air is composed of one part of oxygen and 
four of nitrogen. Oxygen is the most active constituent, 
as through its agency the most important changes are 
wrought. Sometimes nitrogen is spoken of as a mere 
diluting agent, but it has other incidental uses. 
3. Carbonic acid gas, or carbon dioxide (C02), is always 
present in the air in from three to four parts in 10,000, 
63 64 
Hygiene. 
but its presence is not known to be related to animal 
life. To this extent it is generally claimed as a natural 
constituent of air. But if increased to six or seven parts 
in 10,000 it becomes a direct interference with health, 
and when up to ten parts is very injurious to most 
persons. If increased to more than this, it will destroy 
life. It is heavier than oxygen or nitrogen, and so, unless 
heated, tends to sink into the lower strata of air. Its 
production is going on constantly in all combustion 
processes and the respiratory acts of all animal life. It 
is one of the gases of decomposition. Vegetation appro- 
priates much of this product. 
It has sometimes been claimed that plants and flowers 
are healthful in living and sleeping rooms because of this. 
It is true that green and living plants in air or sunlight 
do appropriate carbonic acid gas. But dead leaves and 
dowers do not. With all the moistening and enriching 
necessary to house-plants, they certainly do not improve 
house air, and deteriorate it unless they are green and 
well attended to. Ammonia is also present in small quan- 
tities in the outside air. Ozone, which is oxygen in a 
condensed form, is present in certain qualities of air, as 
that in the open country or amid mountains and forests. 
It seems to have a greater power of oxidation and purifi- 
cation than oxygen itself, and is claimed as a test of the 
value of some localities as health resorts. 
4. The air always contains more or less aqueous vapor, 
which is insensible to ordinary vision and feeling, or 
appears in fog, dew, rain, snow, or hail. Air is said to 
be saturated when it will hold no more moisture. But 
by raising the temperature the capacity for moisture is 
increased. The amount generally present varies from fifty A in, Light, Sun-heat, and Climate. 
65 
to seventy-five per cent. Where the air is both high 
in temperature and saturated with moisture, the heat 
becomes especially oppressive. The wind of very hot and 
saturated air is not cooling. 
5. Air has impurities added to it in various ways. If 
taken into our lungs, it comes out with a loss of about 
five per cent of oxygen and a gain of about five per 
cent of carbonic acid. The expiration of carbonic acid is 
greatest during the day. With this are associated impuri- 
ties of an organic nature, such as putrescible particles of 
various kinds and some of the gases of decay. An adult 
will, with usual activity of life, exhale about twenty cubic 
feet of carbonic acid gas, and thirty grains of unstable 
organic matter, in each day. This amount is much in- 
creased by great activity or by a bad condition of health. 
This does not include organic material from the skin or 
other sources which also get into the air. Numerous im- 
purities get into the air from without. All combustion, 
from the burning of a candle to that in the engine, con- 
sumes oxygen and gives out carbonic acid gas. Smoke, 
gas, dust, all forms of organic particles, minute specks 
of all vegetable and animal life, find their way into this 
great ocean of atmosphere above and around us. One has 
only to let the sunshine strike through a small chink in 
an apartment to see what multitudes of floating particles 
become visible. These are but specimens of a countless 
host too small to be seen by the unaided eye. In addi- 
tion, there are minute forms of vegetable and animal life 
in countless numbers, some of them conservative of pur- 
ity, but many of them, by their excretion or changes, 
adding to the suspended matter of the air. 
6. In the out-of-door atmosphere, the provisions of 66 
Hygiene. 
nature are in general fully adequate to the care of all the 
exhalations of the earth, and all the forms of mineral, 
animal, or vegetable matter, without risk to human life or 
health. There is such diffusion and chemical combination 
as not only to neutralize but to change these into valuable 
material. But in the artificial conditions of life, where 
there is not the same opportunity to carry far away the 
floating material or to neutralize it, or where the product 
is far more rapid and abundant than in natural condi- 
tions, we get such production of impure air as is dan- 
gerous to human health, and must be provided for by 
various methods of adjustment. In many industries and 
arts there is great liberation of deleterious matters. 
7. All impure air has a tendency to irritate the minute 
membranes of the throat and lungs, and to deprive us 
of that amount of oxygen needed for healthy respiration. 
The breathing of foul air, also, enfeebles lung power, 
diminishes skin circulation, and makes us much more 
liable to colds and other maladies. The minute forms 
of organic life, intended for conservative uses, are so 
over-nourished by such abundant material as to take on 
exuberant growth and multiplication. So the higher life 
is too often embarrassed or succumbs to the conditions of 
foulness, which make these lower forms disease-breeding 
and pestiferous. 
8. It is not wonderful that so many diseases result from 
foul air when we consider how dwellings, assembly-rooms, 
and all indoor industries, tend to accumulate deleterious 
substances, to prevent free circulation of air, and to pro- 
duce the gases of decay. Modern life has greatly added 
to these evils. Houses are built more compactly. Heat 
is introduced from cellar to attic. The gases from tires Air, Light, Sun-iieat, and Climate. 
67 
and lights add to the carbonic and other gases unfriendly 
to health and life. A usual gas-burner removes as much 
oxygen and produces as much carbonic acid gas as four 
or five men. It is only not so harmful because not laden 
with organic and decayable matter, but is still deleterious, 
and in large quantities destructive of life. Various other 
worse forms of gaseous substances are produced, as car- 
bonic oxide, marsh-gas, sulphuretted hydrogen, etc. Even 
where the air is only confined and dry, wre have a great 
sense of relief in the change to the purer air of the 
open country. 
9. Purity of Air. — There are various ways by which 
we test the purity of air. The most ready and common 
of these is by sense of smell, so that when wre pass into a 
room differing a little in purity from the outer air we 
perceive a difference. But the trouble with this test is 
that this sense is so easily blunted, and what we once 
perceived soon becomes unnoticeable. Besides this, there 
are other impressions made upon the sensory system, as 
when we are conscious of dryness, or of feeling uncom- 
fortable in a close room, or in certain conditions of 
atmosphere. 
10. The chief reliance now' is on microscopical and 
chemical examination of the air. With the microscope, 
we are able to detect the various floating particles, and 
to determine whether they are organic, and if so, whether 
alive or dead, and if inorganic, what form of substance 
they represent. The thermometer, the barometer, or the 
hygrometer come to our aid in determining questions 
of temperature and moisture. 
Chemical examination has aided very much, and espe- 
cially as conducted by R. Angus Smith in his studies 68 
Hygiene. 
of chemical climatology. He devoted himself much to 
the examination of outside air, and shows how, not- 
withstanding the laws of diffusion, the air of towns, 
with its smoke, its particles and acids and gases, is not 
so uniformly good as that of the country, and that 
the air of mountains and valleys differs from that 
of closely-built country districts. Suffice it here to say, 
as to chemical examination, that it is now possible to 
estimate the carbonic acid and various other gases, and 
the organic impurities contained in the atmosphere, as 
well as many of their sources and the amount produced. 
It is upon these that many of the rules as to heating and 
ventilation are based, as will be seen in the chapter on 
that subject. 
11. Our standard of pure air is to be derived from its 
composition as found in nature, and from the experiences 
of careful observers as to localities where the air is found 
especially beneficial. Thus it is a valuable fact, if it can 
be shown, that ozone or condensed oxygen abounds more 
in hilly than in city districts, and that such air is to be 
considered pure and more beneficial for this cause. Hav- 
ing ascertained fully what constitutes pure air and the 
deterioration to which it is subject, we are ready to con- 
sider what are the qualities needing to be supplied to 
persons living or kept in inclosures, under certain defined 
conditions as to position, numbers, etc. 
12. The quantity of air needed to be supplied to a room 
containing a given number of persons has been vari- 
ously computed. In order to approach correctness, many 
facts have to be taken into consideration. Thus a room 
occupied as a hospital produces air of a greater degree 
of foulness than the usual room as occupied by well Air, Light, Sun-heat, and Climate. 
69 
persons. Something depends on the mode of building, 
since some houses have more windows, cracks, and crev- 
ices than others, or have walls of less thickness, or are so 
inclosed as to cause dampness, and interfere with the free 
and rapid distribution of air. The design of houses 
should not be to exclude air, but to introduce it without 
undue draught. Even the walls should not be air-tight. 
Rooms differ much as to the amount of dust, or other 
forms of animal, mineral, or vegetable matter introduced 
into them, as well as in its readiness to decomposition 
and decay. As fires and lights consume oxygen and 
furnish carbonic acid gas, and as these are often asso- 
ciated with dust and various gases, and with varying 
currents or movements of the air, these too are to be 
considered. Sanitarians have not failed to take into con- 
sideration all these modifications; to experiment upon the 
effect of different causes, or of several of them differ- 
ently combined. The first basis generally considered is 
that of the needs of each individual. 
13. Not far from 400 cubic feet of air passes through 
the lungs of each person in a state of ordinary activity 
every twenty-four hours. In this time, the lungs take out 
of the air about 18 cubic feet of oxygen, and put into it 
about 18 cubic feet of carbonic acid gas. In the same 
time an average of about one-half pint of impure water 
goes out from the lungs, and about 30 grains of putres- 
cible organic matter, in addition to as much or more from 
the skin. Children are more active in their vital pro- 
cesses than older persons, and in the period of school- 
life are generally reckoned as needing about the same 
amount of air as adults. 
14. If we rest our calculation on the amount of carbonic 70 
Hygiene. 
acid gas exhaled, which is quite an approximate meas- 
ure of other impurities, and upon the amount of oxygen 
removed, there would be about 17 cubic feet of air that 
lias been disposed of each hour, and so disposed of as 
not only to deprive it of its purity, but to give back into 
the remaining air materials which, with every one of the 
eighteen expirations per minute, was reducing its purity. 
If a person should be shut up in an air-tight box, ten 
feet long, ten feet wide, and ten feet high, it would be but 
a very few minutes before there would be a cry for more 
air. As an ordinary stove, burning anthracite coal, for 
every pound of fuel burned consumes 2§ pounds of oxy- 
gen, or 32 cubic feet, corresponding to the amount in 
1000 cubic feet of air, this greatly adds to the exhaustion. 
As the combustion of one cubic foot of coal or lighting- 
gas consumes the oxygen of 10 cubic feet of air, and 
produces 2 cubic feet of carbonic acid, the demand would 
be all the sooner if lights were being used. One pound 
of oil consumes the oxygen of 130 cubic feet of air, and 
produces about 21 cubic feet of carbonic acid. Whenever 
the heating is done by apparatus located in the room, 
a consumption of oxygen takes place, with the addition 
of dust and gases. This is only partly compensated for 
by the draught caused. 
A careful study of these facts, and careful tests of the 
quantity of these constituents in the air of various 
rooms, has led to the following conclusions, which, 
although not claimed as absolutely accurate, are so ap- 
proximate as to have received the assent of the best 
authorities. 
The minimum amount of cubic space in a room which 
should be allowed for each person is as follows: — Air, Light, Sun-iieat, and Climate. 
71 
In a school-room 250feet. 
In a dwelling, in a room constantly occupied all day 
or all night 300 “ 
In a tenement or lodging-house 350 “ 
In a hospital ward 1000 “ 
In computing cubic space two things are by experi- 
ment shown to be essential. First, that the height of a 
room over twelve feet should be disregarded; and, second, 
that of the cubic space, the floor space should not be too 
little. Three by four, or twelve square feet, is the small- 
est floor space approved of for each pupil in a school- 
room. 
The bases of these calculations are, first, the amount of 
cubic feet of air per head needed each hour; second, the 
necessity of so introducing it as not to cause draught; 
and, third, the general result of experience as to the 
effects produced by lesser quantities. 
15. To supply the amount of pure incoming air neces- 
sary to change the air without draught, so as to keep the 
carbonic acid, etc. below the standard of from 6 to 7 parts 
in 10,000, it is found that at least three times the amount 
of air per hour needs to be introduced that is allowed for 
the cubic space. Where there are fires and lights which 
derive their combustion by consuming the oxygen of the 
room-air, the amount often needs to be doubled. With 
this general statement as a guide, it needs to be said, in 
addition, that so many are the modifications arising from 
exposure of location, from material and shape of inclosure, 
from prevailing winds, from changes in atmosphere, from 
character of audience and length of occupancy, that it 
often seems desirable to make local tests by the thermom- 
eter, the hygrometer, the Angus Smith carbonic acid test, 72 
Hygiene. 
the senses of persons coming in out of pure air, besides a 
few chemical tests which may be resorted to. 
16. The Angus Smith test is thus stated: Keep the room 
so that the air gives no precipitate when a ten and a half 
ounce bottle is shaken with half an ounce of clear lime- 
water. To make the test, clean a wide-mouthed bottle 
and fill it with pure rain-water. Empty out the water 
in the room so that the bottle will fill with the room- 
air. Wait until it is dry and pour into the bottle a half- 
ounce of clear lime-water and shake thoroughly. If there 
be no trace of turbidity or milkiness, it does not con- 
tain more than eight parts in 10,000 of carbonic acid gas. 
This will show that the amount of carbonic acid present 
is not beyond the amount consistent with health. 
Ammonia, sulphuretted hydrogen, and ammonia sul- 
phide when present can be detected as follows: For the 
ammonia test tincture of logwood is evaporated to dry- 
ness and the residue dissolved in ether. Strips of filter- 
ing-paper are dipped in it, to which ammonia gives a 
brownish color. In the Frankland water-test process 
we have already noted the significance of ammonia. 
Sulphuretted hydrogen is best detected by exposing 
strips of blotting-paper dipped in a solution of acetate 
of lead. 
Ammonia sulphide is detected by paper dipped in a 
solution of nitro-prusside of sodium. All these are asso- 
ciate gases of decomposition. 
17. Moisture of Air. — Although we have already 
spoken of water, we need again specially to notice it as 
a constituent of air. For the relation of health or life 
to the moisture in the air is not less vital than to the air 
itself. About twenty-two per cent of all the heat that Air, Light, Sun-heat, and Climate. 
73 
leaves the body passes off by evaporation. Upon it our 
comfort largely depends. This evaporation depends much 
upon the amount of moisture in the air. Leaving out of 
consideration that which is condensed and appears as 
rain, frost, hail, snow, or dew, the insensible moisture of 
the air, like the insensible perspiration of the body, is 
one of the essential, regulative forces for health. 
There is a sense in which the atmosphere in which we 
live may be said to consist of a mechanical mixture of air 
and watery vapor. 
Air is said to be saturated with vapor or moisture, 
when the space occupied by the air and the vapor will 
not admit of the presence of any more vapor. But the 
capacity of air to contain vapor of water increases rapidly 
with the increase of temperature. 
Prof. C. F. Brackett illustrates it thus: “ If one pound 
of air at 32° F. were saturated with moisture it would 
contain .00379 pounds of water. If, now, the whole were 
heated to 42° F. it would no longer be saturated, since at 
this temperature a pound of air would be capable of 
holding .00561 pounds. Merely heating the pound of air 
together with the vapor contained in it has changed its 
hygrometric state from complete saturation to one which 
is only 68 per cent saturated. In like manner, if the 
temperature were successively raised to 52°, 62°, 72° F. 
the corresponding degrees of saturation would be 46, 32, 
and 23 per cent.” 
18. As evaporation from our bodies is to us not only a 
comfort but a condition of health, if we are placed in an 
atmosphere warm and saturated with moisture, we are 
far more uncomfortable than in an atmosphere of greater 
warmth with less moisture. If, however, with a raised 74 
Hygiene. 
temperature, the degree of saturation with moisture falls 
very low, as to .23, we ourselves are called upon to impart 
more, and great dryness and discomfort result. While 
we have not control over the outer conditions of moist- 
ure, we can, by change of clothing, of exposure, and of 
climate often get the desirable or necessary results. 
It is a fallacy to suppose that the windows of a room 
must be closed on wet days to keep the damp out. Damp 
air is only hazardous when the point of saturation is 
nearly reached. With the temperature of a room moder- 
ately high and the introduction of air without direct 
draught, the damp outside air is far better than the 
confined air within. When we come to speak of ventila- 
tion and heating we shall have occasion to consider more 
fully the artificial relations of in-door life to air, and how 
they can be regulated. 
19. Light as related to Health. — In considering the 
eye we shall have occasion to consider light in its special 
relations to it. But besides this, light has a very important 
influence upon general health, growth, and increase of 
vigor. It is one of the conditions of vital action. Carter 
the oculist speaks of it thus: “ The potatoes which germi- 
nate in a dark cellar and push out straggling white and 
sickly roots toward any chink by which sunbeams pene- 
trate the darkness, the artificially bleached celery and sea- 
kale of the gardener, the children who grow up in shaded 
lanes and dark alleys of great cities, the work-people who 
labor in cellars or mines, all alike proclaim the great 
truth, that light without sunlight is only half living.” 
Want of sunlight, to the human race, means stunted 
bodies, imperfectly formed blood, feeble limbs, dull senses, 
and torpid minds. Essential to the well-being of those Air, Light, Sun-heat, and Climate. 
75 
who are reputed to be healthy, it is no less essential to 
the recovery of the sick. There are well-authenticated 
instances of hospitals having a light and a dark side in 
which the percentage of recovery has been distinctly 
greater on the former; and a like influence upon the 
health of inmates has been repeatedly observed in schools, 
barracks, asylums, and other public buildings. “ Who,” 
says Miss Nightingale, “has not observed the purifying 
effect of light, and especially of direct sunlight, upon the 
air of a room ? ” It is well known that the inhabitants 
of those sides of deep valleys on which no sunshine 
ever comes are apt to be pale, stunted, and deformed. 
20. The value of sun-baths was known to the ancients. 
While there must be some adjustment to circumstances, 
it is certain that it is desirable to have not only light, but 
sunlight, enter living-rooms and school-rooms. Also, that 
there be enough windows to secure light nearly as it is 
had in the great open. Because sunlight tends to bleach 
curtains and other adornments, it is too often shut out 
where most needed. It is far better to choose fabrics 
that will not be thus affected and that have no folds 
for retaining dust. A thin material will subdue direct 
solar light, so that it will not dazzle and yet admit the 
warming rays into the room. Fluted or ground glass 
will change the rays of the sun, and yet increase the 
amount of light that finds entrance, and can be used in 
certain windows of schools with advantage. 
21. The effort as to every school-room should be to have 
no interruptions to full light. Many city school-rooms by 
reason of adjacent buildings, and many country school- 
houses by reason of adjacent trees, are too much shaded. 
Ever bear in mind that it is not merely a question whether 76 
Hygiene. 
one can see, but also whether the cheering and healthful 
and transforming power of bright, pure light is secured. 
No doubt the direct rays of the sun will sometimes show 
an amount of particles floating in the atmosphere of the 
room sufficient to surprise those who regarded the air 
as very pure; but this will only serve to emphasize the 
need of avoiding all kinds of dust in the school-room. 
The effect of full light, if let in from proper directions, 
is always to aid in comfort as well as in health. When 
not occupied, buildings and rooms are greatly benefited 
by the free admission of sun as well as air, so that all 
dampness may be overcome, and sun and draught may 
unite in their cleansing and purifying work. Many ex- 
periments have been made which show the effect of 
different degrees of light. Good authorities claim that, 
were it possible, school and other houses should be located 
with their corners toward the cardinal points, as thus we 
are more likely to secure some sunshine in each room on 
every sunny day. 
22. Electricity, as contained in the atmosphere, and as 
related both to light and heat, is also to be regarded 
as associated with the air and as modifying its conditions. 
But neither science nor experience as yet enable us to 
speak of it in this relation, or of its general influence on 
health. 
23. Heat as related to Human Health.—While heat 
has so many and such important relations to human 
health and welfare, its chief consideration needs to be 
deferred to those chapters in which we consider our cloth- 
ing and our foods, and the action of the body as related 
to heat. 
As a general statement, the sun is the source of all heat. A in, Iagiit, Sun-heat, and Climate. 
77 
Materials are divisible into those which are good or bad 
conductors of heat. As heat becomes stored in various 
substances which thus become known as fuel, so animal 
heat is stored in food. One of the chief activities and 
functions of the human body is to convert other sub- 
stances into animal heat. Being thus converted, it is 
often a question how to so relate the body to clothing and 
to the outer world as to hasten the removal of heat when 
desirable, and to secure retention of heat when we need 
more warmth. By the laws of conversion and adjust- 
ment, the body tends to such an equality of internal heat 
that 98.6° F. can be stated as the normal temperature. 
But notwithstanding this, our sensations are subject to 
varied impressions of heat and cold, such as affect the 
health even when not changing the internal temperature. 
Or if the shock is great, or a disease intense, the internal 
temperature may be raised from the normal standard to 
105° or more, but with great risk to life. The produc- 
tion of heat for us by means of foods, and in most climates 
by the artificial aid of fuel, is an indispensable necessity. 
24. Our best warmth is that derived from foods and 
from exercise and other natural stimuli of internal pro- 
cesses. Next to this, is the use of such variations in day 
and night clothing as will retain sufficient heat to prevent 
chilliness and make us comfortable. The consideration 
of all this will find its place in connection with the subject 
of Heating and Ventilation. 
25. Climate and Health. — Most of these surroundings, 
or outside influences, that we have been considering, go 
to make what we call the climate. Meteorology is the 
science which treats of the atmosphere and its phe- 
nomena. Climatology is the science which treats of the 78 
Hygiene. 
causes which affect the climate at a particular place. By 
the climate of a place, we understand its peculiar con- 
dition with respect to temperature, moisture, and other 
atmospheric phenomena. By weather we understand the 
condition of the atmosphere at a particular time with 
respect to temperature, moisture, winds, cloudiness, etc. 
Climate, while depending primarily on (a) the distance 
from the ecjuator, (b) the distance from the sea or very 
large bodies of water, (c) the height above the sea, and (d) 
prevailing winds, depends also (c) on the drainage of the 
ground, (/) the character and contour of the geological 
structure, (g) the amount of forests, (h) the rainfall, (i) 
the cultivation of the soil, (j) the access of light and heat, 
and other minor influences. 
26. Hence, in studying climate, we are studying the 
effect of various combinations and modifications of our 
surroundings. Continental and oceanic outlines; the in- 
terspersion of islands in the seas, and of lakes in the lands; 
the disposing of mountain-chains and forests, to interrupt 
or change the direction of winds and to condense the moist- 
ure they bear; the courses of the valleys, determining 
those of the rivers; the character of the soil in respect to 
radiation and absorption of heat; the nature and extent 
of vegetation; the slope, as to sun and wind exposure; 
and various other things, affect climate in general, and 
even give a variety of climate to localities not far distant 
from each other. 
While instruments of precision and the classified obser- 
vations of many observers furnish us general indications, 
we often have occasion to take these only as guides, and 
then learn by our own experience what locality is best fit- 
ted to our own physical condition. Health often depends Am, Light, Sun-heat, and Climate. 
79 
either upon change of locality, or upon a proper adjust- 
ment of ourselves to the conditions of the locality in 
which we have to reside. 
Our houses and our clothing are among our first and 
most important attempts at this adjustment, and have 
value to the extent that they serve to adapt us to our 
surroundings. As these are the primary artificial efforts 
we make to adjust ourselves to our surroundings, and as 
the skin is the medium of contact with the world about 
us, these will be considered when we come to treat of it. Chapter V. 
SHORT LESSONS IN THE ANATOMY OF THE HUMAN FRAME, 
AS RELATED TO THE HYGIENIC CARE OF THE BODY. 
HAVING thus considered the more immediate sur- 
roundings* of man which have most to do with his 
life and his health, before any further consideration of 
these or of other natural relationship with the outer world, 
it will be necessary to pass to another division of Hygiene, 
namely, to such consideration of human structure and 
function as will enable us to present those mutual rela- 
tions and conditions which have to do with the main- 
tenance of health. In so doing, it will also be convenient 
to point out the indications as to hygienic management 
and the promotion of sanitary welfare. 
2, The human form or substance is made up of bones, 
muscles, tendons, ligaments, organs, arteries, veins, lymph- 
vessels, nerves, tissues, skin, hair, and nails. Of these, 
taking one hundred and fifty-four pounds as the aver- 
age weight, the bones make about twenty-four pounds. 
They are of shapes and sizes suited for the various 
purposes for which they are intended. As spoken of to- 
gether, they form the skeleton. They are united by liga- 
ments and cartilages. The number of bones is differently 
stated, accordingly as some which at an early period of 
life are separated become united, or as some very small 
bones allied to cartilage are classified with them. Some 
also include the teeth, while others name them separately 
80 Bones of the 
Head and Face. 
Clavicle, or Collar-bone. 
Bones of Vertebral Column. 
-Scapula, or Shoulder-bone. 
Sternum, or Breast-bone. 
Ribs.' 
Humerus. 
Ulna. 
Pelvis, including (S.) Sacrum and 
(O.) Coccyx. 
Radius. 
Carpus, or Wrist.—Eight 
small bones. 
Hand. — (19) bones. 
Femur. 
Patella. 
Tibia, or Large Bone of Fore-leg., 
Fibula, or small Splint Bone of Leg. 
Tarsus, or Ankle and Heel Bones (7), 
Bones of Foot.— Nineteen bones. 
FIG. III. —The Human Skeleton, showing- position of bones 82 
Hygiene. 
as a special form of bony structure. The number as thus 
given varies from two hundred to two hundred and four- 
teen, or to two hundred and forty-six if the thirty-two 
permanent teeth are included. The bones differ in shape 
and hardness, and are variously penetrated by blood- 
vessels and nerves. During growth hardening is not com- 
plete. Except where there is articular cartilage for joints 
or motion, the bones are covered with a thin, tough, vas- 
cular membrane known as the periosteum, or bone-cover- 
ing. Sometimes, when a bone is severely bruised, without 
being broken, it sets up inflammation in this covering, 
and a variety of felon results, which is very painful. 
3. The bones are the principal levers, which so co-operate 
as to support the body erect, and which, through the dis- 
tribution and action of manifold muscles, secure for it its 
power of motion and the exercise of force. The accom- 
panying skeleton in profile, and the parts as given there- 
with, show the relations of these various bones, and how 
they unite to make up the bony structure. Also the front 
view of the scapula, or shoulder-blade, the thorax, or 
chest, the pelvis, and the spinal vertebrae shows more fully 
their individual shapes. 
The bones which form the head are at first eight in 
number, and so joined as to admit of compression, 
motion, and change of shape; but as the brain which they 
cover grows, and as the head needs more protection, they 
come to be solidified into one arch of solid bone. 
Of the fourteen bones which are usually spoken of as 
those of the face, the two nasal bones which form the 
bridge of the nose, the two malar or cheek-bones, and the 
lower maxillary, or jaw-bone, chiefly give form to the face. 
The bones of the back or spine are so arranged as to fit Hygienic Care of the Body. 
83 
one upon another, and admit of motion, by which, with- 
out much change in any one, and by the action of all, the 
body is flexible, and can be bent forward and to the side, 
Spinal Cord. 
Vertebrae. 
Processes, or Ridge of Spine 
■Natural Curves of the Spine. 
Natural Curve 
-Sacrum. 
.. Coccyx. 
FIG. IV. —The Vertebral Column. 
and to a degree backward, without injury. Five of the 
lower vertebrae of the backbone unite to form the sacrum, 
and four more to form the coccyx, or end of the vertebral 
column. 
4. The bones of the chest admit of free motion for 
breathing and for other purposes. These are the sternum, 
or breast-bone, the ribs and the vertebrae, to which they 
are joined. 
The bones of the arms and legs are so arranged as to 
secure free motion in many directions. Thus the humerus, 
or upper arm, with its round joint, and the radius and 84 
Hygiene. 
ulna of the lower arm, securing a rolling motion, with the 
eight small bones of the wrist, and the nineteen of each 
hand, give great facility of movement. The shoulder- 
bone, or scapula, is remarkable in that the muscles, with 
Sternum, or Breast-Bone. 
Cartilage end of Breast- 
Bone. 
Ribs. 
Ribs.- 
Lower Floating Rib. 
12th 
Dorsal Vertebra. 
FIG. V. — The Bones of the Human Thorax. 
only the aid of a single slight bone, the clavicle, or collar- 
bone as a brace, are able to give it firmness of position, 
and yet secure for it that mobility which makes it, with 
Acromion, or Clavicle-Joint. 
Glenoid, or Shoulder-Joint. 
FIG. VI. —The Scapula, or Shoulder-Bone. 
the arm, the forearm, and the hand, the most wonderful 
machine the world has ever known. 
The pelvis (Lat. a basin) is the irregular hollow bone 
forming the lower part of the body, which supports the Hygienic Care of the Body. 
85 
contents of the abdomen, and transmits the weight of the 
body to the lower limbs. It is formed by the union of 
Sacrum. 
Crest of Pelvis. 
Acetabulum, or Hip-Joint 
FIG. VII.-The Pelvis. 
the two large side or hip bones with the sacrum and the 
coccyx. The lower limbs, made up of the femur or long 
bone, and the tibia and fibula with the patella as the knee- 
Patella. 
Head 
-Head. 
Shaft of Tibia. - 
Shaft of Fibula. 
Internal Malleolus. 
■External Malleolus. 
FIG. VIII.—The Left Tibia and Fibula and Patella. 
cap, give firmness and yet great mobility to the body. 
Thus the weight of the body is transmitted to the foot 
with its elongated heel and its arch of bones. 
5. A few of the bones are worthy of special notice, be- 
cause of their more manifest and skillful adaptation to 86 
Hygiene. 
particular uses. Thus, as we shall see, the bones of the 
interior of the ear are arranged to move loosely and 
readily on each other to aid in promoting sound. The 
bone which supports the tongue (hyoid bone) is firm, 
and yet itself movable and not fastened to other bones. 
The lower jaw is set at such relation to the upper as 
to secure great force when, by the action of muscles, 
pressure is sought to be made against the upper jaw for 
the mastication of food. The ribs are adjusted to each 
other so as to rise upward and forward, and recede down- 
ward and backward instead of in a direct line. 
6. The bones of the forearm are so fixed as to give ro- 
tary as well as angular motion. This is accomplished 
by the radius or outer bone being small at the elbow, and 
yet forming the chief part of the joint at the wrist, while 
on the other hand the ulna or inner bone forms the joint 
at the elbow, and in its turn has but a small size at the 
wrist. These are so bound together by bands and liga- 
ments, and so moved by muscles as to allow a variety of 
movement unsurpassed in any human mechanism. 
The wrist and ankle bones are many in number, so as 
to give freedom of motion, and yet are very firmly bound 
together. The bones of the hand are so related to each 
other, and the thumb to the hands and fingers, as to 
secure mobility and strength. The patella, or loose bone 
over the knee, is located in the tendon of a muscle so as 
to give mobility, and yet secure a direction of force and 
greater power. The foot, by its shape, secures the strength 
of an arch, and yet a mobility essential for its variety of 
work. These but illustrate great varieties of adaptation 
and design, constantly apparent in the study of structure. 
The bones are united to each other by joints of various Hygienic Care of tiie Body. 
87 
kinds, such as the broad or hinge-joint at the elbow, or 
the ball-and-socket joint of the thigh-bone, and by great 
varieties of modification of these suited to particular 
localities and uses. 
7. Hygiene is greatly concerned in recognizing the 
perfect adaptation of parts and in enforcing those rules 
which preserve the bony structure and secure for it its 
best capacity. When we find how accurately each part 
is adapted to its work, and how all the parts as joined 
together co-operate for the one purpose of life and health, 
we are the more easily led to avoid deviations and in- 
fringements. 
It is the province of Hygiene to teach how bones are 
(a) to have their proper nutriment, (b) to be preserved 
from distortion by improper posture, exercise, or manage- 
ment, and (c) to be protected from injury by accident. 
For their proper nutriment the body should receive 
such food, both as to quality and quantity, as contains 
the materials of which they are composed, or such as the 
organs of the body are able to convert into such material. 
What these are will appear when we come to study the 
foods adapted to the human system. 
For preservation from distortion, it must, first of all, 
be remembered that, although bones seem firm, they are 
capable of becoming distorted, or may suffer in nutrition, 
by the use of food deficient in the properties they need. 
They may also become bent or deformed by mechanical 
means. Pressure on the bone of the forehead has caused 
a tribe of people to be known as flat-head Indians. Pres- 
sure on the bones of the foot has made the Chinese noted 
for their compressed feet, and has injured the gait and 
comfort of many other people. 88 
Hygiene. 
8. Carelessness as to posture in sitting, standing, or 
walking has often caused curvature of the spine, and thus 
greatly interfered with that adjustment of cones and pyra- 
mids which it forms and which sustains the spinal column. 
Careful examination shows that the spinal cord is made 
up of three distinct pyramids joining each other and 
having great accuracy of adjustment. It also has a cervi- 
cal curve forward and a dorsal or sacral curve back- 
ward. Desks and tables, chairs, and other seats need to 
be of size and shape suited to those who are to make use 
of them. 
It is to be borne in mind that the prevention of distor- 
tion also depends much on the condition and use of the 
muscles and tendons and ligaments attached to the vari- 
ous bones, to be considered hereafter. AVe have dis- 
tortion of the bones and the muscles illustrated in what 
is known as pigeon-breast or hollow-breast, where the 
shape of the thorax has been changed by position or 
pressure. Drooping shoulders or bowed limbs are often 
the result of habit or dress, and can generally be corrected 
during youth. If not, the contour of the bones is dis- 
turbed, arches or columns lose their symmetry and 
spinal curvature or other forms of one-sidedness occur. 
Although the deformities made by habit or by fashion 
are not confined to bones, a notice of a few of these 
habits will illustrate how subversive they are of all 
laws of health, and of the most perfect use of the animal 
mechanism. 
9. It is not necessary to refer to the extremes of these 
deformities, as found in a few very barbarous tribes 
where cutting of the flesh as well as deformity of the 
bones has been carried to a great extent. Hygenic Care of the Body. 
89 
The teeth are often deformed by art. Among some 
African tribes a triangular piece is filed away between 
each of the central incisors, or front teeth, and so a gap 
made in the middle of the front row. A recent writer has 
shown how the thumb-sucking of children will produce 
change in the shape of the lower lip and in the form 
of the lower jaw and teeth. This and other like habits 
FIG. IX. —Thorax: Natural shape. 
account for a pointed chin and other changes in the 
lower jaw, as inherited by children. In collections, many 
skulls are to be found, — as those of the Chinook Indians 
of the neighborhood of the Columbia river, and the 
Quinchuas of Peru,—which show depressed foreheads 
and elongated heads caused by systematic pressure. 
10. How the thorax and all that constitute the chest 90 
Hygiene. 
and waist has suffered, is shown by the comparison of 
two such figures as these, although the unnatural one is 
presented as by no means an extreme case. Unnatural 
pressure in the region of the diaphragm is not unusual 
in both sexes. Change of the natural shape of the waist 
by tiglit-lacing and systematic compression of the ribs 
FIG. X. — Thorax: Unnatural shape 
not only interferes with the free action of the lungs, but is 
an embarrassment to the functions of several of the most 
important organs concerned in digestion. It also inter- 
feres with the remarkable nervous distribution in the 
vicinity of the stomach, and in too many cases has been 
the incipient cause of those nervous conditions too often 
found in those who would otherwise have been free tliere- Hygenig Care of the Body. 
91 
from. Tight waist-bands, or the carrying of a large 
amount of clothing suspended from the hips, is also 
objectionable. While the sides of the large bone of the 
pelvis are well adapted for the bearing of some weight, if 
so adjusted as to fall there, great advantage is gained by 
dividing weight with the shoulder by means of straps or 
elastic bands. The processes of life conducted by the vital 
organs of the body are too essential for us to trespass 
FIG. XI. — L, Liver. S, Stomach. 
upon them by any of those external appliances which 
tend to compress them or to interfere with natural free- 
dom of motion. This figure shows the situation of some 
of these organs. 
11. These are examples of common deformities. 
The narrow boots or shoes of men which tend to 
cramp the foot and compress the toes are even surpassed 
by some forms of ladies’ shoes. 92 
Hygiene. 
How the human foot has suffered, even in Christian 
lands, the following figures will illustrate: — 
FIG. XII. —Foot, Natural Shape. 
FIG. XIII.-Foot Deformed 
12. In the action of walking, the foot expands in 
length and breadth; in length often as much as one tenth, 
in breadth even more. Shoes should be made right and 
left. The heel should be low and broad, so that the 
weight is not thrown on the toes, and so that the gastroc- 
nemii and solei, or leg muscles, can act, which they can- 
not do with a high heel. The broad, flat heel gives a 
good base for the column which forms the line from the 
center of gravity. The inner line of the shoe should be 
made so straight as not to push outward the great toe in 
the least degree. For marching boots, a slight bulge is 
often made over the base of the great toe, to allow easy 
play for the large joint. While the instep may be snug, 
room must be left for the fore part of the foot as it touches Hygienic Care of the Body. 
93 
the ground, and for the toes, which have important power 
of adjustment, and were never meant to overlap each 
other. They are the terminal springs of the foot. 
Tibia. 
Astragalus, or 
Heel Bone. 
FIG. XIV. — Showing Bones of the Foot and Ankle 
The relations of the foot as an arch to bear up the 
body, and to give elasticity of motion of parts, are here 
shown. 
13. Deformities of the pelvis are sometimes caused by 
modes of standing or sitting or walking in childhood. 
Some persons show such defect of solidity in bones, 
or such weakness in the ligaments and muscles about 
them, that, when the bones do not break, they bend 
in various shapes and cause deformity. This is to be 
remedied in part by exercise and proper food. While 
formation and growth are natural processes, we are ever 
to bear in mind that we have great control over them. 
As in the system of the natural world, so in the human 
system, we can do much to determine form and strength. 
We must see to it that the body in all its parts has the 
best chance for perfection, and especially that the bony 
framework does not become changed beyond the reach 
of repair. Chapter VI. 
MUSCLES. - BODILY EXERCISES. - CALISTHENICS. 
"ly/TUSCLES are bundles of fiber which have contrac- 
ItJL tility, or power of shortening under the command 
of the will, or under influences independent of the will. 
When these influences are suspended, they return to their 
original place and shape. 
Muscles are of twro classes, voluntary and involuntary; or 
those subject to the control of the will, and those acting 
under some other form of stimulus. The first class form 
the bulk of the muscles, and are chiefly distributed to 
the bony framework. The second are chiefly within the 
cavities of the body, and have to do with the vital pro- 
cesses of circulation, respiration, digestion, etc. 
We have first to do with the voluntary muscles. They 
make up in weight about forty-four per cent of the body. 
These are chiefly intended to direct and control the 
movements of the various bones, although occasionally 
there are muscles which by co-ordinate movements with 
or upon other muscles also accomplish change of direction 
or exert power. By placing one hand around the larger 
muscle of the upper arm, and moving the forearm back- 
ward and forward, one may obtain an idea of muscular 
power and action. This figure of the forearm furnishes 
an example of how muscles of various sizes and shapes 
are formed, and by their tendons attached to bones. As 
the muscles are usually attached to bones, and act as so 
94 The Muscles. 
95 
many levers or strings to pull them one way or another, 
they may even come to be means of deforming bones. 
When a bone is out of its line of direction, or broken, 
they serve to draw it still more 
out of its place, and so occasion 
much pain. 
2. These muscles depend for 
their strength upon the general 
condition of health, upon food 
proper in quality and quantity, 
and upon such exercise and use 
or training as are found to develop 
and strengthen them. Thus the 
muscle in the arm of the black- 
smith becomes, by his vocation, 
developed into a size and power 
beyond what would be the direct 
result of proper food and good 
healtli. As the bony structure de- 
pends much for its right position 
and power upon the good condi- 
tion of muscles which are co-oper- 
ative with or essential to each 
other, we are never to lose sight 
of the dependency of the one upon 
the other. In all these studies 
of different parts of the human 
mechanism, while parts are capable of special develop- 
ment and vigor, it is to be borne in mind that all parts 
are more or less dependent on each other, and that, as 
a rule, the perfection of any local part is not possible 
without a good condition of the whole system. 
Muscle. 
Tendon 
FIG. XV.—Left Forearm. 96 
Hygiene. 
3. Tendons, or sinews (Lat. tendere, to stretch) are the in- 
elastic white cords by which muscles are attached to the 
bones. They are really the connective tissue, or thin 
sheath which covers the muscle extended to the bone or 
attachment-point, so as to form a tendon. Thus, by pla- 
cing the hand at the back part of the ankle, just above 
the heel, and moving the muscle of the leg, you may 
feel the tendo Achilles, which is the tendon of a large 
muscle of the leg, and is attached to the heel-bone. 
4. Ligaments (Lat. ligare, to bind) are the tough bands, 
or strings of white fibrous material, by which bones, in- 
tended for more or less movement, are held closely enough 
in place not to allow of their slipping out of place under 
ordinary circumstances. When there is such a slip, it is 
called a dislocation. When there is a severe pulling or 
twisting, which does not displace any bone, but strains the 
ligaments, it is called a sprain. When this kind of sub- 
stance is much strained, it is generally slow to recover. 
The term dislocation is chiefly applied to bones when out 
of place; but sometimes a large ligament is thrown out 
of place more than in a sprain, and is said to be dislo- 
cated. When there is the breaking of a bone, it is called 
a fracture. Bones, where they meet for joints or motion, 
are enclosed or covered with a tissue or substance called 
synovial membrane, which secretes a slippery fluid to pre- 
vent friction. Then the ligaments qye bound about or 
over this. When the substance is a little harder or more 
dense than the tendon or ligament, it is called cartilage, 
or gristle. Bones themselves may be said to be carti- 
lage, or connective tissue, hardened by being united with 
lime or other mineral ingredients. 
5. As with bones so with muscles, their general vigor de- The Muscles. 
97 
pends upon the welfare of the whole system. Yet muscles 
and sets of muscles admit of special care and training. It 
is to be borne in mind that many muscles are intended 
to co-operate with and assist each other, while others are 
for purposes directly opposite. Thus, when we chew food, 
there are several muscles of different forms and shapes that 
bring the lower jaw against the upper. When we bend 
the forearm upon the arm, there is a class of muscles 
called flexors, on the front of the arm, that bring it into 
tins position. When we desire to straighten it again, there 
is another class on the back of the arm, called extensors, 
that enable us to extend it at full length. There are, 
again, muscles on each side of the body that are the 
analogues or complements of each other, as those each 
side of the breast-bone and between the ribs, or those 
running along each side of the back. The erect position 
on two feet, which seems so natural, results from the ad- 
justment of a multitude of muscles which co-ordinate or 
balance each other. It is our power over their action, and 
the quickness of its exercise, that enables us to keep the 
center of gravity and to change it so often. It is possible 
to develop one class of muscles so much as to make one 
side of the body much stronger than the other, and so 
make us lop-sided. 
6. Thus the bones themselves may be drawn from their 
exact shape and position by a too constant action of one 
set of muscles. We sometimes see the effect of this in 
those who, very early in life, occupy a wrong position 
in play, work, or study. It is surprising how often exact 
measurements reveal the fact that persons who have not 
been aware of any lack of symmetry of either side are 
found to vary more or less from a perfect standard. Both 98 
Hygiene. 
health, power, and grace of motion depend much upon a 
developed or preserved symmetry, for which the skeleton 
and its muscles are well adapted. 
7. Exercise is of importance because it is education. 
All true education is that which secures healthful de- 
velopment. There is constantly going on in the human 
system a process of decay and renewal, a using up of 
force, and a production of new force from materials fur- 
nished. Thought as well as bodily exertion causes waste 
of material, and demands resupply. Life and health are 
always dependent upon this relationship of demand and 
waste, and of supply to the reinvigoration or resupply of 
the material needed for the continuance, not only of work, 
but of the process of living. Within limits, nature has 
great resources of adjustment and compensation, and 
when deprived of her supply by overwork, or by too 
tardy resupply, will still avail herself of various means 
within the system. But this is only temporary, and is 
always a tax on vital force. 
8. It is because exercise has so much to do with the 
destruction and renewal of the body, that it becomes 
an essential consideration. Exercise is the chief agent 
in the renovation of tissue, and is needful because in 
the processes of life all tissue is undergoing destruc- 
tion. It quickens the circulation of the blood, which 
is the remover of waste and the bearer of nour- 
ishing material. It especially aids the action of the 
minute blood-vessels or capillaries. It, therefore, not only 
quickens the activity of circulation, but also that of the 
involuntary muscles which have to do with the inspira- 
tion and expiration of air. The influence of increased 
circulation and respiration is felt in all the organs, and Bodily Exercise. 
99 
so digestion and all natural secretion is promoted. To the 
persons in process of growth it is even more important, 
because, besides supplying daily waste, it is contributing 
to development, and determining the size, functions, 
powers, and habits of the whole body. 
9. While exercise is primarily the use and movement 
of the voluntary muscles, it includes far more than this. 
It is their use in such way as to affect the whole system. 
By it, the activity of all voluntary muscles, and to some 
extent of the involuntary muscles, and the activity of the 
functions of all organs, are more or less determined. Ex- 
ercise influences the rapidity of action in the lungs, the 
heart, and other vital parts. The functional ability of 
every organ is in relation to its activity, or is affected 
thereby. 
10. Modes of exercise are fundamental in their influence, 
since not mere motion, but such motion as affects also 
involuntary muscles to some degree, and such as affect 
organs and their functions, is essential. As exercise also 
has a relation to the outer world, and brings the powers 
of the body either into co-action with or antagonism to 
other powers, it must be adapted to these co-operations 
or antagonisms. Thus, walking up a hill or stairs, or 
carrying a weight, or pushing as distinct from pulling, 
are specimens of modes of exercise called out by motion 
amid other forces. 
11. We are to learn much as to exercise, or the use of 
muscles, from the methods that are natural. We find 
all muscular action is intermittent, and that much of it 
is interchangeable. Parts are relieved not only by alter- 
nation, contraction, and rest, but also by the fact that one 
set of muscles often relieves the other by compensating 100 
Hygiene. 
for their tardy work, or by quite directly substituting 
their work or by resting disabled parts. 
So great is this influence of exercise over the involun- 
tary muscles, over respiration, circulation, perspiration, 
secretions, and all forms of organic or functional action, 
that, while the human system has a perfect apparatus 
for life, it is dependent upon the aid of exercise for its 
efficient operation and proper continuance. Not only the 
heart, but all the vessels, are so responsive to the influence 
of work, or use, that they have been called “ hollow mus- 
cles,” since all these innumerable ducts have a contrac- 
tile or elastic power, which, like the heart, is affected 
more or less by exercise. 
While the ability of bodily exercise depends on the 
muscular and respiratory systems these, in their turn, are 
much affected as to vigor and efficiency by exercise. 
Therefore, if asked what exercise does, the reply is: 
12. (a) It increases the size and power of the voluntary 
muscles employed. 
(b) It increases the functional capacity of the involun- 
tary muscles employed. 
(c) It promotes the health and strength of the whole 
body by increasing respiration, quickening circulation, 
and sending more blood through the minute vessels of 
the organs and the minute vessels of the skin. It has 
a broader and more useful service when guided by a 
knowledge of anatomy and physiology, since it can be 
made to aid those who are of a weak organization, or 
who, because of accident or neglect, need repair or re- 
construction. It is well to have great physical strength, 
but this is not indispensable, since there may be sym- 
metry and good health without it. Bodily Exercise. 
101 
(d) Exercise may preserve or recover health where it 
does not impart great strength. Indeed, there is a dis- 
tinction between that kind of exercise which is intended 
to fit a person to exert great muscular force, or to perform 
some feat with a class of muscles, and that which is 
merely intended to sustain a general vigor of constitu- 
tion, and to fit one for the ordinary duties of life. 
More attention is now being given to what is called 
body-building, or a general and equable development of 
all the parts, than to mere muscular training. 
(e) We are to adapt exercise to persons, to circumstances, 
and to conditions, and sometimes to particular organs that 
show lack of development or vigor. To over-develop a set 
of muscles, as those of the arm for great lifting, does not 
always include a strengthening of the whole framework. 
It is body-building we need; we are to seek such vital 
capacity, such adjustment of all the parts, as will best 
sustain the whole. Many a person loses health because 
there is a defect in one vital part even when all the rest of 
the system is in good condition. The strength of a chain 
is to be estimated by that of its weakest link, and this is 
too often the case as to the strength of the body. Where 
we cannot fully repair or bring a person fully up to a 
standard of health, we can study the type of the indi- 
vidual, and bring him up to a higher standard of comfort 
and vigor. We use the resources we have to acquire 
more. All do not begin with the same capital of health, 
or even acquire it, but they can, at least, learn what their 
capital is, and its ability of preservation or increase, and 
live accordingly. 
13. Hence, while we can give some general rules or an- 
nounce some general principles as to exercise, there are 102 
Hygiene. 
details which need adaptation to individual cases. Exer- 
cise should he regulated by individual fitness, and should 
he gradually increased with increasing strength. Hence 
the art often needs, like any other instruction, to be 
taught by those who have knowledge, and who, by 
practice, have learned to discern the indications. It 
cannot all be taught by books. 
14. Health is not the mere vigor of the present, but the 
power to work long, to work well, and to endure unto the 
end. For this, one needs not only strength for the daily 
routine of life, but such as will give reaction and recu- 
peration from the strain and fatigue which, with all our 
caution, is pretty sure now and then to overtake one who 
attempts to meet the work and responsibilities of life. All 
this requires a thorough appreciation of physical educa- 
tion in school life, and a thorough course of instruction 
therein. 
15. There are a few rules as to exercise which, with this 
understanding, may serve as general guides. Some refer- 
ences to particular exercises may aid those who cannot 
fully avail themselves of teachers. 
Very active exercise should not be taken just after 
a full meal. The reason of this is, that the supply of 
vital force is generally diminished just before a needed 
meal, and that digestion itself, in its first processes, has 
not yet refurnished the system. Observation shows us 
that most animals incline to quiet immediately after 
eating. 
Active exercise before breakfast is not generally bene- 
ficial. No doubt it may be advantageous to such as 
have large vital force; but experiment shows that it is 
better, after so long a fast, to take some nourishment 
before exercise. B ODIL Y Ex EE CISE. 
103 
16. The forms of exercise most to be relied upon by 
those in good health, and who are not seeking to remedy 
any special disability, are such as bring into play the most 
of the voluntary muscles used for change of place. 
Walking is a specimen of natural exercise, and, like 
some others, has this advantage, that it also gives us 
change of air and change of scene. On the other hand, 
stair-climbing is a form of unnatural exercise, which, if 
frequent and long continued, is an injury to many, and 
especially in schools. The most uniform rule as to the ex- 
tent and degree of exercise is that it shall continue until 
there is a feeling of glow or warmth of surface, or a slight 
perspiration. Exercise may be carried beyond this without 
harm, as is often necessary in work, and of advantage 
during the process of growth. But the value of exercise, 
as such, is generally reached when there is glow and 
slight perspiration. A feeling of fatigue is always an 
indication of a needed, partial or continued rest, or a 
change as to the mode of exercise. 
The kinds of exercise needed for special ailments or de- 
fects are to be recognized as quite distinct from those for 
the general educational benefit of the whole body. Thus 
the Swedish or Ling and the Zander systems are espe- 
cially adapted to those who are below their usual vigor, 
while the McLaren, Spencer, and Sargent systems are 
for general service. 
Bathing is to be recognized as an important exercise, in- 
asmuch as much of its benefit is derived from the strip- 
ping, rubbing, and oiling, the sun-bath and manipulation 
which may be used therewith. Indeed, for many it is to 
be ranked more as an exercise than anything else. 
Exercise should always be taken where the ventilation 104 
Hygiene. 
is good. As all active movements tend to increase the 
amount of air inhaled, it is important that it be not 
contaminated in any wise. 
Natural breathing, as opposed to holding the breath, 
is important during all exercise, and such deliberation 
as prevents all unnecessary straining to accomplish the 
object sought. 
17. Special Aids to Exercise, — Athletics, Gymnas- 
tics, Calisthenics. — In order that the body may receive 
proper exercise, that the bones and the muscles attached 
to them may be kept in the best order, and the vari- 
ous organs be aided in their functions, resort is had to 
various artificial systems, especially for the discipline of 
voluntary motion. These are known as athletics, gym- 
nastics, and calisthenics. Athletics refers chiefly to games 
or methods of skill practiced for contest, and exercise such 
as wrestling, boxing, fencing, jumping, running, riding, 
ball-playing, skating, quoits, golf, rowing, etc. Archery, 
croquet, lawn-tennis, and the allied games of la-crosse, 
fives and racket, have made a very valuable addition to 
out-of-door athletics, so that girls as well as boys have 
increased opportunities for recreating exercises. 
The saw is a convenient means of exercise. Have a 
high bench, with a large vise fastened upon it to hold 
the stick of wood. Then use a common coarse hand-saw, 
or use one in each hand. It preserves posture, and is 
an exercise very available for girls as well as boys. It is 
inexpensive, and many a girl can thus secure chest and 
muscle development and great benefit to general health. 
18. Gymnastics, among the Greeks, denoted various 
out-of-door methods of exercise in which the gymnast 
appeared with little clothing for feats and exertions show- Special Aids to Exercise. 
105 
ing vigor, courage, and skill, and developing physical 
power. This training was considered so important, that 
it came to express the entire course of education. So 
in Germany the elementary and high schools are called 
gymnasia. In athletics and gymnastics, only such cloth- 
ing is desirable as taste requires, and such as shall not 
by weight, stiffness, or warmth interfere with freedom of 
motion. 
In gymnastics, the most prominent mechanical aids 
are the horizontal bars, the parallel bars, the vaulting-horse, 
the ropes and rings, and the flying trapeze. In all these 
there is need of special instruction and of studying the 
adaptation of age and constitution. In all more active 
exercises, while the person should rely mostly on a loose 
flannel suit, wraps to moderate the rapidity of cooling, and 
to protect from draught or change of temperature, are 
quite necessary. 
19. In most of those exercises which are termed recre- 
ative, while the occupancy of attention and the skill ac- 
quired are excellent, yet much that is educational is lost 
sight of. In most of these exercises the right arm and 
the lower limbs are so much more used than the rest of 
the body, that they are trained out of harmony with, or 
sometimes at the expense of, other parts. After the body 
is full grown, and all the parts have acquired due form 
and power, this kind of exercise is not apt to go so far as 
to distort. But in the training of youth, the recreative idea 
should be in subjection to the educational, and constant 
effort be made to develop the wholeness of one’s self. 
This means that respiration, blood circulation, nutrition, 
and waste should be studied very closely, and that exer- 
cise should have regard to these more than to mere 106 
Hygiene. 
growth of muscle. When these are assisted in the pro- 
cess of growth, and by due course of training, ordinary 
recreative exercise and prudence quite suffice to main- 
tain them. 
20. Calisthenics relates to those forms of exercise used 
as a system for the development of parts of the body, or for 
general exercise, independent of mechanical contrivance. 
Such are rhymthic movements of the limbs, — musical, 
vocal, and parlor or school-room manual exercises. The 
word calisthenics means beauty and strength, and the 
practice of calisthenics secures both grace of movement 
and vigor of physique by means of rhythmic exercises. 
21. Some of the feats called gymnastic, and various 
forms of athletics, are exhibits of skill and art at the ex- 
pense of health. In all forms of exercise, we must find the 
basis in the demands which the anatomy and physiology 
of the human system indicate, or those special demands 
which departure from the anatomy (deformity or deficient 
development) and disturbance of physiology ('pathology, 
or imperfect function) indicate. The teachings obtained 
by experience, or as the results secured from various 
kinds of bodily discipline, are also a guide. There are 
so many persons not born with perfect conditions for 
health, or not in early life having all the advantages for 
perfectness of form and of function, that very many are 
benefited by modes of exercise skillfully adapted to their 
needs. Every motion should be fully achieved sooner or 
later, according to capacity or increase of strength. 
22. In calisthenics much service can be done by manual 
movements in the school-room which give change of post- 
ure, which rest for a few moments from study, and which 
give at the same time pleasure and recreation. Often, too. Special Aids to Exercise. 
107 
a school-room can be aired during the active exercise of 
the pupils, when they would feel chilly if inactive or in 
a sitting posture. Pupils, while studying their lessons 
at home, may pause five minutes in each half-hour, and 
not really lose any time. The muscles are rested and the 
system refreshed by a change of seat or of position. 
For a knowledge of calisthenics, or of light gymnastics, 
such brief manuals as that of Prof. J. M. Watson, or the 
Home Gymnastics of Hartelius (Lippincott & Co.), or 
the Gymnastic Free Exercises of Ling and Roth (Balliere, 
New York), or the Code-Book of Puritz (Triibner, London), 
will give all needed instruction. These furnish examples 
of movements applicable to all parts of the body, which 
may be accompanied by music, and by the use of light 
apparatus. 
23. In connection with calisthenics, or light gymnastics, 
it is well to employ some of the well-known forms of 
hand apparatus. Hand exercises are conducted with a 
simple wand or bar, which may be round or slightly 
rectangular, and of about two inches or less in diameter. 
These are of great aid in many movements. 
Hand-rings made of cherry or walnut, polished, admit 
of considerable use in pulling exercises, or where the two 
hands are needed to be kept in parallel position. 
Dumb-bells, in all their various sizes and weights and 
lengths, are of important service in developing muscles, 
and for the general invigoration of those of sedentary 
habits. Beginners, as a rule, should use the wooden 
dumb-bells, which can now be had of various sizes and 
weights, and admit of most valuable use. 
Besides the various motions and uses so fully described 
by authors, it is not difficult for any two or three persons, 108 
Hygiene. 
or a class, to agree upon a series of movements, and 
thus give great variety of use. 
We are indebted to the Orientals for the valuable aids 
to exercise known as the Indian Clubs. These come in 
long and short sizes, with diameter of handle and knob 
and entire weight proportioned to those of different ages 
and degrees of strength. 
24. It is not necessary in this manual to note all the 
various devices, many of which admit of light use as well 
as of the more venturesome feats. Those who use the 
manual forms and the lighter apparatus will seek these 
if needed. But the calisthenics of the school-room or the 
small playground do not need more than those we have 
mentioned. Even to those accustomed to active exer- 
cise, they afford change and recreation, and both in the 
home and in the school serve to impress the relation of 
activity and of educated movement to grace of carriage 
as well as to robustness of health. While exercise needs 
to resemble actual labor in all its essential particulars, 
these modifications greatly aid those who pursue no 
manual industry, and by their order of movement aid 
in mental and moral as well as physical culture. 
For all these and other exercises it is to be recognized 
that there must be a corresponding attention to proper 
food, to a proper use of the breathing apparatus, to a 
training of the senses, to sleep and rest, and to all 
those particulars which tend to keep the system in a 
proper condition to exert force. Chapter VII. 
THE SKIN, ITS B'UNCTIONS AND ITS CARE. 
NEXT to some knowledge of the bones and the 
muscles, and their immediate attachments, as re- 
lated to healthy care and use, we pass to a notice of the 
coverings drawn over these which are in closer contact 
with our surroundings. The muscles are sheathed in 
what is called connective tissue, which is continued to the 
end of the tendons. It passes from the true skin to all 
the other parts, and is known as the areolar (Lat. areola, 
a small. open space) or elastic, fibrous, or cellular tissue. 
Tissue (Lat. texere, to weave) is a general word to denote 
organized membranous structure or material. It varies 
in the aspect of its nuclei, or cells. So various modi- 
fications result, and it is called areolar, cellular, or fatty 
tissue, from the variations in the form of the cells 
which are interposed in its meshes. 
The tissue just beneath the skin is oftenest spoken of 
as areolar tissue, and by fat and other deposits is modi- 
fied as to its network, thickness, and structure. 
2. Over this, and indeed as a kind of modification 
thereof, we have the skin or integument which covers 
the whole body. At some points, as the lips, it shades 
off into a similar but more delicate layer, which is redder, 
and is kept moist by giving out a slightly viscid fluid. 
This gives to it the name of mucous membrane. This 
may be called the skin of the internal body. The general 
109 110 
Hygiene. 
outer skin or integument is made up of two parts, the epi- 
dermis and the dermis or true skin, “ cutis vera.” The 
epidermis is really but a hardened secretion from the 
dermis, or true skin, without vessels or nerves. As it 
can be raised, as in a blister, and separated from the true 
skin, it is convenient to speak of it as the epidermis, or 
upper layer. The upper cells thicken and become hard 
on pressure. Its lower surface is a little softer, and in it 
are the pigmentary cells in which the coloring matter 
of the skin is developed or deposited. This determines 
the color or complexion. The corium, or deeper structure, 
consists of strong intertwining fibrous bands, amid which 
are nerves, lymphatics, blood-vessels, fatty tissue, hair- 
follicles, sweat-glands, oil-glands, nerve papillae, etc. 
A gland is an organ whose function is that of secre- 
tion or excretion, or both combined, and which contains 
ducts or vessels for the escape of matter elaborated or 
excreted by the gland. These ducts pass through the 
epidermis and open upon it, 
3. The sudoriferous (Lat. sudor, sweat, and ferre, to fur- 
nish) or sweat-glands, situated in the dermis or corium, 
have each their minute convoluted and spiral tubes or 
ducts, and are so numerous that if extended in one line 
they would make a length of about 24 miles. Krause 
estimates their number at 2,381,248. Says Huxley: 
“They are fewest in the back and neck, where their 
number is not much more than 400 to a square inch. 
They are more numerous on the skin of the palm and 
sole, where their apertures follow the ridges visible on 
the skin, and amount to between 2,000 and 3,000 to the 
square inch. At a rough estimate, the whole integument 
probably possesses not fewer than from two millions and The Skin and its Care. 
111 
a quarter to two millions and a half of these tubules, 
which therefore must possess a very great aggregate of 
excretive power.” Without these glands and their tubules 
there would be some perspiration. The skin would be in 
the position of a moderately thick, permeable membrane 
interposed between a hot fluid, the blood, and the atmos- 
phere. Thus some perspiration would be going on from 
this structural condition, but it would be only slight 
without the sweat-glands. These and their tubes are 
so interposed amid the thin walls of the capillaries as 
to be sure to receive therefrom by transudation. 
4. Besides, or connected with their functions as excre- 
tory organs, their great function is to regulate the heat of 
the body. As the heat of the body is raised by the oxida- 
tion of the food, which is greatly increased by exercise or 
by exposure to extreme heat, a part of it is made latent by 
the conversion of the water into vapor in these sudorifer- 
ous ducts. It passes off from the skin as insensible per- 
spiration, but is often condensed on the skin as sensible 
perspiration. The evaporation causes reduction of heat, 
and so regulates it. If persons long exposed to extreme 
heat cannot perspire there is always danger. A workman 
in the harvest-field was noticed to drink much water, but 
not to perspire as did the rest. A few hours after he fell 
with sunstroke, and died. The amount of insensible 
perspiration each day is from one and one half to two 
pounds avoirdupois. 
5. The cutaneous perspiration is slightly acid, of faint 
odor, and contains saline matter, carbonic acid, and traces 
of lactic, formic, acetic, and butyric acids, with small 
quantities of sebaceous matter and epidermis and epithe- 
lial cells. The skin also slightly absorbs oxygen. Thus 112 
Hygiene. 
frogs have lived several hours with the lungs removed. 
The quantity of carbonic acid is from one-thirtieth to 
one-sixtieth of that excreted by the lungs. 
6. The sweat-glands are greatly affected as to their ac- 
tivity by heat and various atmospheric conditions, by the 
state of the blood, of internal organs, and of the nervous 
system. The nerves open and close the ducts, as the 
conditions of heat and cold may indicate, so that this 
safety-valve apparatus is operated by them. Mental emo- 
tion may cause either a sudden cessation or pouring out 
of perspiration. By cutaneous perspiration alone it has 
been found possible to reduce the weight of a man over 
two pounds in an hour. Thus by profuse sweating 
much solid matter in solution or minute suspension is 
eliminated from the system. Hence various forms of 
forced perspiration have been used to rid the system of 
effete or irritating materials, and to relieve congestion or 
change the abnormal structure and function of internal 
organs. 
So important is the perspiratory power of the skin 
that of old the kidneys and the skin were called the 
common emunctories (Lat. emungo, to bloiv out). These 
organs were so named because they could forcibly 
pour out and separate from the system all unneeded, 
superfluous secretions. 
7. The quantity of water excreted by the skin is in 
general about double that by the lungs. If the skin were 
kept for a time encased in an impermeable covering, as 
shellac or varnish, death would result. The whole amount 
of material thrown off from the skin daily is reckoned 
from 10,000 to 15,000 grains, varying somewhat accord- 
ing to various conditions. The Skin and its Care. 
113 
The skin, with its different layers and glands, is shown 
by the accompanying cut. 
8. The skin, the lungs, and the kidneys need to be 
regarded as associated or complementary organs. 
They are the three chief organs of excretion. 
Ends of Perspiration Ducts. 
Papilla on surface of 
Dermis or Corium. (a) 
■Cuticle or Epidermis. 
Deeper or Kete Muco- 
sum layer of Cuticle. 
Perspiration Duct. 
Perspiration Duct, 
(a) to (b) 
Perspiration Glands. (6) 
Cluster of Fat-cells. 
FIG. XVI. —Vertical Section of the Skin. 
“Different as these organs may be in appearance, 
they are constructed on one and the same principle. 
Each, in ultimate analysis, consists of a very thin sheet 
of tissue, like so much delicate blotting-paper, the one 
face of which is free, or lines a cavity in communica- 
tion with the exterior of the body, while the other is 
in contact with the blood which is to be purified. The 114 
Hygiene. 
excreted matters are, as it were, strained from the blood 
through this delicate layer of filtering-tissue, and on to 
its free surface, whence they make their escape. 
“ Each of these organs is especially concerned in the 
elimination of the chief waste products, — water, car- 
bonic acid, and urea,—though it may at the same time 
be a means for the escape of the others. Thus the 
lungs are especially busied in getting rid of carbonic 
acid, but at the same time they give off a good deal of 
water. The duty of the kidneys is to excrete urea (to- 
gether with other saline matters), but at the same time 
they pass away a large quantity of water, and a trifling 
amount of carbonic acid; while the skin gives off much 
water, some amount of carbonic acid and a quantity of 
saline matter, among which urea is sometimes present.” 
9. In twenty-four hours the skin throws off or excretes 
on an average 10,000 grains, or about eighteen ounces, of 
water; the lungs 5,000 grains, or nine ounces of water; 
the kidneys 24,000 grains, or about fifty ounces. 
The skin throws off about 400 grains of carbonic acid 
in twenty-four hours, of solid matter 300 grains, and so 
is a direct auxiliary to the lungs. In disease it often can 
be made to do far more than this, and so relieves con- 
gestion. 
10. Water is the largest excretion from the skin. More 
gaseous matter is given off by the lungs, and more solid 
matter (1,000 grains) by the kidneys. Through the lungs 
and the skin the body loses much of its liquid and gase- 
ous matter. They are the only parts through which oxy- 
gen is introduced in the blood. The amount through the 
skin in man is not large, hut it is accessory to the lungs. 
In some lower animals the skin contributes much to the The Skin and its Care. 
115 
respiratory function. In general, it may be said that the 
skin partakes of the nature of both lungs and kidneys, 
seeing that it absorbs oxygen and exhales carbonic acid 
and water like the former, while it excretes organic and 
saline matter in solution like the latter. The animal heat 
is regulated by the skin and by the organs of circulation. 
The former keeps down the temperature through the 
agency of the perspiration, by which evaporation is pro- 
moted in a ratio proportionate to the surplus heat gen- 
erated. Nothing tends to keep down the accumulation 
of heat more than evaporation, by which heat is rendered 
latent or insensible. It is thus that the skin regulates 
the animal heat in- a Turkish bath, and that a live animal 
may live in a hot oven in which a dead one would be 
roasted. Our insensible and perceptible perspirations are 
the great regulators of internal beat, so that, however rich 
our foods may be in heat-producing qualities, the tempera- 
ture of the body in a state of health is kept very evenly 
at 98.6° F. 
11. T1 le sebaceous or oil-glands (Lat. sebum, suet) are 
lodged abundantly in the surface of the corium, or deep 
skin. Each gland consists of a single bag or follicle of 
basement membrane lined with epithelium and ducts ter- 
minating in a pouchlike extremity, these having various 
forms. The ceruminous or wax-glands of the ear and 
the glands of the eyelids are of a similar kind. The 
number of sacculi connected with each duct varies from 
two to twenty. The orifices of the ducts open upon the 
surface, and are more numerous about the hair-follicles. 
They are intended to render the skin soft and pliable. 
The retention of sebaceous matter in these ducts, when 
of the larger size, gives rise to specks, as sometimes seen 116 
Hygiene. 
upon the face. In the ear, its accumulation as cerumen 
or wax often causes partial deafness. 
12. T1 le minute hairs scattered in great numbers over 
the skin have their origin in a nerve-sac in the corium, 
or true skin. The sebaceous glands usually connect 
with the hair-sacs, and are lubricated there in the skin. 
These minute ducts are very numerous. The lymphatics 
(Lat. lympha, water), so called because carrying a watery- 
like fluid, are also sometimes called absorbents; from 
their ability of absorbing certain materials for replenish- 
ing the blood. These abound in an interlaced network 
in the upper portion of the corium, where they are in- 
termingled with the capillary and nerve plexuses. The 
nerves are also spread about in the upper surface of the 
corium, with fine branches given off to the papillae either 
as loops or some probably terminating in a free extremity. 
The minute blood-vessels enter amid the areola and inter- 
lacing fibers of the corium and divide into a capillary 
plexus (Lat. pledo, to braid), which feed the sweat and oil 
glands, etc. It is in the minute capillaries of the skin 
that we have the changes manifested by perspiration. 
13. The various parts of the skin are abundantly sup- 
plied with blood-vessels, not only for local nourishment, 
but because the capillary system of which the skin is the 
container does such a great excreting work for the whole 
body. The arterial blood which started from the lungs 
has gathered up very much material needing to be dis- 
posed of before its return to the heart and the pulmonary 
circulation. 
The conversion of arterial into venous blood takes place 
not only in the lungs, but in most of the capillary vessels 
of the body, and especially in that wonderful capillary Tiie Skin and its Care. 
117 
network of vessels found in the skin. A clean, healthy 
skin is therefore constantly aiding the lungs in supplying 
oxygen and removing used-up materials from the blood. 
Any serious derangement in the skin-tissue is quite likely 
to make itself felt upon the delicate pulmonary tissue. 
14. Amid all the areolar network in the corium there 
are not only many blood-vessels, but from it an abundant 
nerve supply passes to the upper layer of the skin. The 
corium is only about one-tenth of an inch in thickness. 
When we have cutis anserina, or goose-skin (<horripilation) 
it is owing to the contractility of the corium, or deeper 
tissue of the true skin about the hair-sacs. The alleged 
standing of “the hair on end,” so far as true, is owing 
to this. 
The papillary layer of the cutis vera, or true skin, con- 
sists of conical papillae upon the free or outside surface 
of the corium. These consist of a convoluted nerve loop 
about one-hundredth of an inch in length, and of single 
or convoluted capillary loops. Both as to size and ar- 
rangement the papillae differ, for while on the general 
surface they are small and quite evenly distributed, in 
sensitive parts, as the lips, hands, and feet, they increase 
in size and numbers. In those parts where sensation is 
very highly developed the nerve fiber has a little point 
within the papillae, sometimes called a “ tactile corpuscle,” 
which seems somehow to add to the delicacy of the sense 
of perception. In some parts the papillae are arranged 
in rows, or collected in small square-shaped masses, 
with a minute sweat-duct orifice in the center. It is 
to this kind of arrangement that the lines and furrows 
we see in the feet and hands are due, these being the 
parts between the rows of papillae. 118 
Hygiene. 
15. We have already noted how the skin and its glands 
have most important functions as to the circulation and 
its relation to the lungs, and the kidneys as excretory or 
separating organs. The skin is wonderfully endowed with 
nerves, and is greatly under their influence. In order to 
keep the circulatory, glandular, excretory, and combus- 
tive processes in proportion or physiological balance, the 
nervous system as distributed in the skin performs a 
most important work. Its relations to organs, to func- 
tions, to sensation, will, perception, secretion and excre- 
tion, circulation, and all physiological action, and to 
many disturbing or pathological processes, is such that, 
like a ready custodian, it is on the alert to provide 
for or prevent contingencies which may impair the wel- 
fare of the body. Some parts are more sensitive than 
others. Besides the general sensibility, it is made to 
subserve the special sense of touch. Experiments with 
the points of compasses, blunted with pointed pieces of 
cork, have enabled Weber and others to determine the 
various degrees of sensibility of different parts. Thus 
the two points of the compass can be distinguished from 
each other at a distance of one-twenty-fourth of an inch 
at the tip of the tongue, one-fourth of an inch at the tip 
of the nose, five-twelfths of an inch at the palm of the 
hand, at the tips of the fingers one-twclftli of an inch, 
and five-sixths of an inch on the forehead. 
16. Upon the dermis is a superficial layer composed of 
minute particles which are being constantly shed off in 
scales or scarf-skin and as rapidly reproduced. This 
latter is called the epidermis. It is seen separate when 
by some irritant, as a burn, a blister is raised. 
This epidermis, cuticle, or scarf-skin is accurately mod- Tiie Skin and its Care. 
119 
elled on the papillary layer of the cutis vera, or true skin, 
and may also be spoken of as of two parts, namely, the 
epidermis proper and the rete mucosum, or {mucous, net, L.) 
membrane containing the coloring-matter. The color is 
dependent upon pigment, or coloring-matter in the cells, 
just as we have it similarly in the choroid coat of the eye 
and in the different colors of hair. Were it not for the 
epidermis, the skin would absorb too readily, for we see, if 
we remove it, as by a blister, how quickly any substance 
sprinkled over it enters into the circulation. The exter- 
nal or denser surface of the epidermis consists mostly 
of thin scales, and being subjected to friction they are 
flattened and made harder and desquamated; hence they 
are constantly falling off. 
Then, again, as in the case of workmen, or in exposed 
parts, the epidermis thickens, and so protects the hands, 
feet, and other surfaces. Where there is too much press- 
ure, or friction long continued, it becomes hardened by 
pressure into successive layers, the upper ones being 
broader than the lower, and so a kind of cone or peg is 
formed, with its apex downward. So corns are formed, 
and come to be very troublesome, and so also bunions 
and various results of this pressure and friction occur. 
Thus the thickening which is intended on the hands, feet, 
and other exposed points, and at the flexure of joints, to 
protect, becomes by over use or abuse a source of pain. 
17. Some idea of the amount of the loose epidermis, 
and of its quick reproduction, can be formed by soaking 
the feet, and then removing all the scarf-skin that can be 
rubbed or scraped off, and looking at it under a micro- 
scope. Those who have to be engaged in kinds of work 
that subject one spot to great friction do well, by oil and 120 
Hygiene. 
by covering, to afford special protection. Corns and bun- 
ions are avoided by a perfect fit of shoe. When there 
are the first evidences of undue friction, a softening of 
the part by warm water and frequent oiling, or the use 
of a borax-wash, will help to prevent subsequent irrita- 
tion. All loose skin that can be easily removed should be 
scraped off with a smooth, hard edge, and the shoe that 
is very tight, or so loose as to constantly rub against parts 
of the foot, should give place to one that fits. 
18. The hair is essentially epidermis, composed of co- 
alesced cells inclosed in a kind of sac, with a papillae. 
The hair is developed by the superficial cells coating the 
papilla being adjusted one upon another so as to form a 
shaft or continuous extension of epidermic cells. 
There is constant formation of new sacs and papillae, 
and of material for the shaft from the bottom, so that 
the hair is pushed forward, and its ends drop off after 
reaching their length. The shaft consists of a central 
pith, or medullary substance, which sometimes contains 
air, and of a cortical substance and an outer cuticle. The 
outside epidermic cells form a root-sheath around the 
root of the hair, which when it is pulled generally comes 
away with it. The hairs scattered over the skin evi- 
dently have slight movement under contraction of the 
corium, and with their oil-glands and their minute ori- 
fices help the functions of the skin. A good head of hair 
numbers over 100,000 hairs. The number, scattered all 
over the body near these minute gland-openings, amount 
to many thousands. 
19. Nails have a similar development. A bed of elon- 
gated papillae is formed, covered with growing epidermic 
cells in ridges which flatten and coalesce so as to form The Skin and its'Care. 
121 
the nail, and it is thrust forward by new growth, much 
after the manner of a hair. 
It has been thus necessary to give with some detail the 
anatomy and physiology of the skin, because it is so com- 
plex, has so many offices connected with health, and is so 
external as to be far more subject to outer influences than 
some inner membranes. It is not only a covering, but -a 
counterpart to all it covers, and a basis for adjustment 
between ourselves and the surrounding world. We have 
seen that, besides other variations in tissue, it has a won- 
derful network of circulatory vessels, of perspiratory and 
oil glands, and their ducts, with hair and nails formed 
of its own materials, besides pigment and other cells of 
various special type. 
20. When we consider the uses of the skin in the ani- 
mal economy we find that, (a) as an organ of excretion it 
ranks with the lungs and the kidneys; that, (b) as an 
organ of respiration it absorbs oxygen and yields car- 
bonic acid, and has other interchanges that show it to 
be both excretive and absorptive. Upon it (c) more than 
upon any other part of the system we depend for the 
regulation of the temperature of the body, so essential 
to life and health, (d) It is an organ of sensation and 
touch. 
21. Besides the protection it gives to the whole body 
as a covering, it has its own special provisions by means 
of (e) perspiratory and oil glands and hair-follicles and 
nails, and indicates to us its need of being unimpeded 
and often aided in its effort to rid the system from 
used-up material, to secure additional supplies, and to 
serve as a medium of exchange between that inner world 
(microcosm) which we call man and that outer world 122 
Hygiene. 
(macrocosm), on his relation to which his welfare so much 
depends. It is, therefore, to be regarded not so much as 
a covering as an organ having complicated and essential 
relations to the whole system, — an outspread sheet of 
membrane, having offices similar to the more concealed 
sheets of folded vessels packed away under the name of 
lungs or kidney, and having in addition a collateral rela- 
tion to the various and internal physiological processes 
of life. 
22. It might be suggested that an organ showing such 
provision for cleanliness and for heat regulation might 
be depended upon to regulate itself, without any gratui- 
tous offer of assistance from our own wills. But it is to 
be remembered that to a very great degree the adjustment 
of life to external conditions has been committed to our- 
selves. We have, in common with other animals, been 
endowed with instincts to a much greater degree than is 
generally recognized, by which we almost insensibly and 
as a matter of course make changes that are indicated. 
But as man is endowed with planning and thinking 
powers beyond the brute, he is also expected to find out 
by experience how to aid nature or how to adapt himself 
to changes. 
23. It is also to be remembered that man, as we find 
him, is not in a natural state. He has been subjected 
to changes and influences which give types of heredity 
that affect not only individuals, but nations. Changes 
of climate, life in houses or in closely packed streets, sub- 
jection to various kinds of diet and embarrassments to 
health which arise from various mistakes or failures, or 
from the inroads of disease, are only to be met under that 
law of adaptability and adjustment which has so merci- 
fully been put under the regulation of the individual. The Skin and its Care. 
123 
From a study of all the facts to which physiology 
points, and which careful experience has certified, we are 
able to give very many rules that serve to aid us in 
management. While these rules are not absolute, they 
are very efficient as guides, and even the necessary devia- 
tions from them often become capable of determination. 
24. Care of the Skin, and its Functions. — Surely we 
may state cleanliness as the first indication in respect 
to the skin. The very fact that it is a secreting organ, 
that it has sweat-glands and oil-glands, and that im- 
portant changes are constantly going on in the blood 
as it passes from one set of vessels through minute capil- 
laries or the walls of very thin membranes to another set 
of vessels, determine the fact that it must not be sealed 
up by any form of dirt or organic matter of any kind. 
Experience is constantly attesting how much can be 
done in health and in disease by wise attention to the 
skin. We are familiar with the fact that these minute 
ducts, which open by millions on the skin, may become 
impeded by specks of retained matter, generally, but not 
always, too small for the naked eye to perceive. 
We know, too, what wonderful effects can be produced 
upon the skin by the reaction following the use of water, 
and how the minute capillary vessels come to be better 
filled with blood, and have a more active circulation. 
The same is true of the lymphatics, which reach the skin, 
and which will be more fully described, in connection 
with the larger circulatory system. 
No doubt the great means by which we relieve conges- 
tion of the internal organs, or their embarrassed functions, 
is through attention to the warmth and circulation of 
the skin. Its nerve condition, too, is much affected in the 124 
Hygiene 
same way. Even a mustard-piaster, by the redness it 
produces and the relief it often gives to internal pain, 
illustrates what can be done, either by direct or reflex 
nervous impression, to effect internal conditions. 
25. The four principal methods, either alone or com- 
bined, by which we are to promote the health of the skin, 
and its adaptation to the needs of internal organs, are 
washing or bathing, soaping, oiling, and rubbing. Each, 
first of all, is valuable as a means of removal for all 
excretions from the skin, including not only the various 
secretions, but the minute scales of epidermis or scarf-skin 
which are so numerous, and which should be frequently 
rubbed off. All the four methods named give help in 
this direction. Often they are to be combined. It is one 
of the advantages of the bath, that it so often means, or 
should mean, the combination of all these to the degree 
that may be indicated, and that in the employment 
of these there may be derived many of all the benefits 
of general and recreatory exercise. 
26. Even the ordinary washing, morning and night, 
means a very different thing to different persons. The 
man who stops at a stream, washes a little dirt from the 
hands, bathes the face a moment, and then rushes on, has 
used water, and may be refreshed by its coolness and wet- 
ness, but has not done much washing. From this up to a 
complete morning toilet there are more degrees of varia- 
tion than some imagine. Should not the chief toilet be 
at night? A proper washing always includes a cleansing 
of the nails, a careful washing about the eyes and in the 
ears, a bathing of the neck, and such drying of the sur- 
face as amounts to a light friction of the skin. There is 
some reason to claim that these parts need more frequent The Skin and its Care. 
125 
ablution than others, because more exposed to floating 
particles in the air. Next to these, the feet need most 
frequent cleansing. This arises from the fact that their 
frequent use causes more scarf-skin and secretion than 
most other parts. Being surrounded by a somewhat 
more impermeable covering than the rest of the body, the 
secretions do not find so ready diffusion. The nails, too, 
serve as points for the retention of effete material. It is 
not near as much the custom as it should be for persons 
to wash the feet daily. It need not be a foot-bath, but a 
simple wiping of the feet with a towel wet with cold or 
warm water, and a proper drying. There is no danger 
of taking cold from such a habit, but the feet are much 
more likely to be kept warm and to be fitted to endure 
cold or sudden changes. 
27. The use of water all over the body, for the sake of 
cleanliness, varies with different persons. Some have a 
thicker skin, or are more abundant in their skin secre- 
tions, than others. While there is some force in the idea 
that those who perspire freely have more need for fre- 
quent washing, to remove the solid materials of the per- 
spiration; yet it is also true that those of sedentary 
habits seem more likely to have stoppage of various 
ducts, and because of this need to have the skin more 
thoroughly washed and stimulated by friction. We have 
known persons so frequent and thorough in their ab- 
lution as to weaken and irritate the skin; but, as a rule, 
the error is in the other direction. 
Most persons are benefited by a daily washing, or bath, 
and we have never known a person by nature so cleanly 
as not to be benefited at least by a weekly wash. 
Gibbon says that for a long time Rome needed no 126 
Hygiene. 
physician but the bath, and there is no doubt that the 
bath is a preventive as well as a remedial measure. 
As chilliness and shivering are not desirable, there are 
many who do best to bathe in a room of a temperature 
of 65° or 70° F., and to whom water not too cool is best 
suited. 
28. As to the temperature of the water, baths may be 
classified as follows: — 
Cold bath, 60° F. to freezing-point. 
Cool bath, 60° to 75° F. 
Tepid bath, 85° to 92° F. 
Warm bath, 92° to 98° F. 
Hot bath, 98° to 112° F. 
Blythe divides as follows: — 
Cold bath, 33° to 75° F. 
Temperate bath, 75° to 82° F. 
Tepid bath, 82° to 90° F. 
Warm bath, 90° to 98° F. 
Hot bath, 98° to 112° F. 
The usual internal heat of the body in health is quite 
uniformly maintained at 98.6°, whatever may be the cool- 
ness of the atmosphere at the outer surface of the skin. 
29. The question has been raised whether complete 
submersion of the body under the water for several min- 
utes, as in swimming, is not unnatural, as it deprives the 
bod}r of its relation to the air, for which it is intended. 
There is reason to believe that such entire submersion 
should not be continued very long at a time. An able 
English physician has drawn attention to it as a cause 
of congestion of internal organs, and some diseases have 
been attributed thereto. In bathing for cleanliness, it is 
not necessary. The time spent in the water in sea-bath- 
ing is very apt to be longer than is best for health. The Skin and its Care 
127 
30. The benefits of bathing are much increased, both 
in promoting cleanliness and in softening the skin, by 
the use of soap, or some form of alkali. This use is based 
on the fact that the oil-glands of the skin may be defi- 
cient in action, or that small openings in it have become 
clogged or covered, or the scarf-skin has become by press- 
ure or otherwise unusually adherent. As borax or soda 
will unite with the oily matter found in the skin, or will 
neutralize the acid of the sweat, and thus of themselves 
form a surface-soap, they are often used instead of, or 
alternately with, soap. It is often well to rub the entire 
body with a good quality of castile-soap, with only just 
enough water to make of it a lather, and so, for a few 
minutes before the washing, lubricate the body. In 
persons whose skin was sallow or lacked whiteness we 
have seen great benefit from this method of rubbing and 
softening the skin. The method now known as Massage, 
in which there is such a bathing, soaping, and kneading 
of the integument and muscles as to soften them, and 
increase flow of blood and nervous sensibility, has been 
found in many cases advantageous. 
31. The oiling of the skin, so common among Oriental 
nations, is not so much needed in climates where clothing 
is used; but where there is apparant dryness of the skin, 
and feeble capillary circulation, it is of great advantage. 
The slight absorbent power of the skin is thus utilized, 
and it also tends to excite the glands of the skin into 
action. The amount of oil to be used is generally slight, 
and such kinds as have the least stearine are to be pre- 
ferred. No doubt many of the liniments, which chiefly 
consist of some form of oil, cut or rendered more absorb- 
able by alcohol or ammonia, are useful in this way. 128 
Hygiene. 
When the skin has suffered in sickness, as in many 
fevers, and notably in scarlet-fever, the oiling has many 
advantages. The oiling should generally, within twenty- 
four hours, be followed by a tepid bath, or a washing 
of the surface with soft water, in which soda or borax 
is used in the proportions of a tablespoonful to a gal- 
lon of water, or else some form of soap which is a ready 
solvent. 
32. In all use of hard water it is well to remember that 
its solvent properties are small. In fact, the continuous 
use of hard water often chaps the hands and face and 
roughens the skin. When the water is hard, it is better 
to use rain-water, or such as has been boiled. 
The use of soap removes the temporary hardness of 
water, for by the mutual action of the soap and the com- 
pounds of lime and magnesia, the latter are converted into 
a lime (magnesia soap), and so a soft water is left by con- 
verting the mineral matter into an insoluble substance, 
or curd. Thus some soap is wasted, but the water is im- 
proved. Ordinary washing-soda softens water in the same 
way. So, also, on a large scale, as where water is needed 
to be softened for laundry purposes, a saturated solution 
of lime-water, or milk of lime, is made and added to the 
water. This unites chemically with the carbonate of lime 
in the water and precipitates it. As waters differ in hard- 
ness, the proportions needed somewhat differ. But, for 
ordinary hardness, one part of lime-water to about twelve 
parts of water will generally be sufficient. 
In all matters relating to bathing and cleansing, the 
use of soft water is quite important. 
33. Friction of the skin is valuable as a means of se- 
curing its healthy condition and that of the whole body. The Skin and its Care. 
129 
We do not mean by this such hard rubbing as may be 
carried to the extent of irritation. But it is the general, 
gentle rubbing of the whole surface that is greatly condu- 
cive to health. The bare hands may be used for this 
purpose. Only those who have methodically practiced 
it know how the skin can be warmed and exhilarated 
in this way. It is the best remedy for cold feet or 
cold hands. A short time thus spent at the time of ris- 
ing from bed, or before getting out of bed, or at even- 
ing upon retiring, aids much to quicken the capillary 
circulation, and to give a sensation of warmth. It is 
valuable for cleanliness, because it facilitates the removal 
of organic particles, and of the epidermis or scarf-skin. 
Sensitiveness of skin, and its power of sensation as an 
organ of touch, will be considered in connection with 
the organs of special sense. 
34. In thus considering cleanliness we have, in fact, 
considered most that relates to our control over the skin 
as related to health; for one cannot thus treat it without 
promoting its secretion and excretion, its transpiration, 
its equability, or capacity to adjust temperature to our 
needs. The unimpeded circulation thus secured is the 
best guaranty against cold, and a great promoter of 
general good health. Chapter VIII. 
CLOTHING AND HABITATIONS AS OUR NEXT PROTEC- 
TION FOR HEALTH. 
CLOTHING is important, not because it can originate 
or create warmth, but because it so utilizes the heat 
produced as to keep the air that is circulating about our 
bodies warm enough to make us comfortable. 
So, in speaking of the skin, we associate with it the 
clothing. For many its only meaning seems to be that 
which has to do with decency, beauty, and taste. Im- 
portant as all these are, the most important view to be 
taken of clothing is that which relates to the health. It 
is the additional skin which, because of changes of tem- 
perature and of conditions, often necessarily artificial, we 
are called upon to provide. Its design is to obstruct or 
regulate the abstraction of heat, which, as we learn from 
Physics, goes on from every warm or moist body placed 
in a cooler atmosphere, either by radiation, evaporation, or 
conduction. 
2. The heat that is radiating from us is kept longer 
about us by our clothing; and even the thinnest cloth- 
ing, such as a veil over the face, will lessen radiation, 
and so help to keep us warm. As about fifty per cent 
of air-heat is, under usual conditions, lost by radiation, 
we need to know how far clothing can interrupt this, 
and what kinds do it most effectually.1 
1 For definitions of Radiation, Conduction, and Convection see 
the chapter on Heating and Ventilation. 
130 Clothing as a Protection for Health. 
131 
When we are surrounded by other bodies, or things 
equally as warm as ourselves, as in artifically heated 
rooms, or in a crowd with persons as warm as ourselves, 
our own radiation is exactly counterbalanced by that 
which is received from our surroundings, and our loss 
is chiefly by conduction and convection. This is chiefly 
accomplished by the currents of air moving about us. 
Fortunately, there is this constant movement of air, 
which is seldom less than one and one-half feet per sec- 
ond, and not perceptible as a draught until it amounts 
to about three feet per second. 
3. Under usual conditions, the losses by radiation and 
conduction are the chief losses of bodily heat. When, how- 
ever, these are insufficient, we fortunately have such a 
supply of sweat-glands and tubing in the skin, and such 
relations of the capillary circulation thereto, that the skin 
increases its insensible perspiration to sensible, and thus 
evaporation reduces the temperature and keeps it from 
becoming excessive. When the skin pours forth water, 
as in perspiring, the evaporation equalizes differences 
resulting from varying production of heat or from em- 
barrassment of the other two methods. We have already 
seen how the miles of sweat-ducts can rapidly deliver 
this liquid. Its importance is seen from the fact that 
to change fifteen drops of water to vapor two and one- 
half caloric units are required.1 
4. Between these three methods there is opportunity 
for delicate adjustment of heat. But even this, in chang- 
ing climates and circumstances, depends much, in varia- 
1 A caloric unit is the heat required to raise the temperature 
of one pound avoirdupois of water one degree Fahrenheit. 132 
Hygiene. 
tion and efficiency, upon the proper adaptation of cloth- 
ing. Consequently, clothing has been very carefully 
studied. A common idea is that clothing is designed to 
shut out the air from our bodies, but as conduction and 
evaporation, and to some degree radiation, depend upon 
air, the complete shutting out of air would not conduce 
to healthy regulation of temperature. 
5. The design of clothing is rather to catch between its 
fibers the circulating air, and so to regulate the tempera- 
ture of the air between the outside and our skins as shall 
make it of comfortable warmth. Heat radiates from, and 
is conducted from or evaporated through, different forms 
and kinds of clothing at quite different rates. Color has 
an influence in relation to radiant heat received. In the 
presence of direct sunlight or flame Pettenkofer found for 
white textures the following proportions: — 
When cotton received 100 
Linen received 98 
Flannel 102 
Silk 108 
With shirtings of different colors the proportions were: 
White 100 
Pale straw color 102 
Dark yellow 140 
Light green 155 
Dark green 165 
Turkish red 168 
Light blue 198 
Black 208 
Hence, in this regard, the order of preference is gen- 
erally stated thus: white, gray, yellow, pink, green, blue, 
and black. 
In the shade these differences nearly disappear. Clothing as a Protection for Health. 
133 
The power of absorbing odors is greatest in the fol- 
lowing order: black, blue, red, green, yellow, white. 
6. Clothing merely means to put materials between 
our skins and the outside air, which shall retard the 
outgoing of heat, and, meeting air, shall warm it before 
it reaches the skin. 
One of the first facts which experiment has shown, and 
which is confirmed by experience, is, that it is not the 
substance and the weight, but the texture and the volume, 
that cause the chief difference. A loose substance, as in 
a new bed-quilt, greatly loses its power to help us retain 
warmth when it becomes compressed or packed. Hence, 
an article like feathers, which cannot be thus packed 
by use into a hard flat surface, is very valuable as a 
covering. The same is true of furs, and especially of 
the light hair near the skin. So three or four layers 
of the same article will keep us warmer than the same 
amount in weight closely compacted. A covering of 
fifty newspapers, for instance, one upon the other, will 
retain heat far more than if the same number are 
compressed into one mass. This is illustrated by the 
coldness of a very tight boot or glove in cold weather, 
as compared with one looser and of the same weight and 
material. Any garment for warmth must, therefore, ad- 
mit of air next to the skin, and in its crevices or meshes. 
So garments made of very fine fiber are warmer in pro- 
portion to weight and thickness than those of coarser fiber. 
Persons who have tried the use of buckskin, or leather, 
or india-rubber, as a clothing, have found themselves 
suffering greatly when exposed to severe cold. These 
have their uses, but only as shutting out water, or cold 
winds, so far as is consistent with the free passage of 
air through garments beneath them. 134 
Hygiene. 
7. “ Our clothing not only renders the air still around 
us, but it also regulates its temperature by the heat which 
leaves our body; we heat our garments, and they con- 
tinually heat the air passing through the meshes and 
] lores of the texture. We may compare our clothing to 
a stove warmed by the heat emanating from our body- 
engine for the purpose of warming the air round our 
surface.” 
8. Another important consideration in the choice of 
clothing for health is that relating to its property of con- 
densing water from the atmosphere, generally known as 
the hygroscopic property of different materials. This 
also, in part, determines the ability of various kinds of 
material to dispose of the perspiration from the body. 
A series of interesting experiments have been made as 
to this with the following results: wool has a greater 
hygroscopic power than linen; the maxima and minima 
of flannel being 175 and 75, and those of linen being 
111 and 41. Linen is quickly wetted and soaked, wool 
more slowly, but linen cannot take up the same quan- 
tity. Evaporation is much quicker with linen. Drying 
proceeds much more evenly in wool. Linen, cotton, 
and silk become very quickly air-tight by wetting, but 
wool only after a long soaking. 
9. The elasticity of fiber, on which the porosity of all 
fabrics chiefly depends, is very different in different 
materials. Here, again, wool stands apart; its fibers do 
not lose much elasticity when they get wet, while wet 
linen and silk lose it rapidly. The greater facility of 
catching cold in wet linen or silk than in wet wool is 
in exact proportion to the greater facility with which 
water expels the air contained in their fibers. Clothing as a Protection for Health. 
135 
The more the air in any material is displaced by 
water the less it keeps us warm, the quicker it conducts 
the heat; hence, the frequent injury resulting from wet 
clothes, and the striking discomfort produced by a damp, 
cold air. 
Cotton has many advantages over linen, but is not so 
universally applicable as wool. It conducts heat more 
rapidly than wool, and less rapidly than linen. It is 
very non-absorbent of water, and so cannot compare with 
wool in hygroscopic properties. Wool, for instance, has 
double the power of cotton or linen to absorb sweat. The 
fiber of cotton becomes hard or packed in wearing, and so 
diminishes in porosity. It has an advantage over wool in 
that it does not shrink in washing. Smallness of thread, 
smoothness of texture, and equality of spinning have 
much to do, not only with the quality, but with its hy- 
gienic value as clothing. When cotton of well-woven, 
smooth texture is mixed with wool, in the proportion of 
about fifty per cent woven in the same thread, it makes 
a valuable garment, which, without unduly diminishing 
the thermal and hygroscopic value of wool, prevents 
shrinkage, by which, in time, the wool fiber itself would 
become harder and less absorbent. All these articles for 
clothing may differ somewhat in their regulative power 
as to heat and moisture by difference in quality as well 
as in material or fineness of thread or texture. Thus, if 
the garments are made of old, or worked-up wool and 
cloth (known as shoddy), the fiber will have been com- 
pressed, and be quite different from that of fresh wool 
or cotton. Smoothness and softness and closeness of texture, 
with weight large in proportion to bulk, are the general 
requirements for suitable clothing. 136 
Hygiene. 
10. Coverings for Different Parts of the Body.— 
Head-covering. The essentials for a good head-covering, 
as to quality and as to material, are the same as for other 
parts of the body, with a few slight modifications. It 
should be remembered that the natural hair of the head 
is a protection against alternations of heat and cold. 
Where there is thinness of hair, or baldness, special 
attention must be given to the protection of the head 
from draughts or from severe cold or heat. 
The head-covering in general should be as light as is 
consistent with durability, and should not press too closely 
the head or the hair. So the band of it about the head 
should not be tight; and, to secure movement of air 
inside, the cap should usually have small perforations in 
the top. Parkes thus describes the Glengary Scotch-cap, 
which he commends: “It is very soft and comfortable, 
presses nowhere on the head, has sufficient height above 
the hair, can be ventilated by openings when desired, 
cannot be easily blown off*, can be carried at the top of 
the head when desired in hot weather, or pulled down 
completely over the forehead and ears in cold weather.” 
How easily the temperature of the air inside of a cap 
may be affected was shown when, in India, white cotton 
covers were ordered for caps in summer, and it reduced 
the temperature of air in the cap about 4° to 7° Fahr. 
In very hot weather a wet handkerchief in the top of 
the hat, if it has good ventilation, acts as a cooler. In all 
close head-dresses, too, little attention is given to the heat 
of the inside air. Women, with all their varieties of head- 
costume, as a rule, have more healthy head-coverings 
than men. Ornament is not to be objected to, if protec- 
tion and lightness are regarded. The addition of large Clothing as a Protection for Health. 
137 
masses of hair is of course objectionable, if, either by 
thickness of covering or weight, it surpasses the ordinary 
provisions of nature. 
Baldness is often hereditary, and results either from 
some condition of ill-health which has caused the falling 
off of the hair, and not infrequently from neglect of the 
scalp or too much cap-covering. 
11. Protection of Face and Neck.—The face and 
the neck are generally safe to be left uncovered, except 
in excessive heat or cold. It may be claimed that slight 
protection of the upper part of the neck is required for 
those exposed to vicissitudes of weather. For this pur- 
pose the beard seems to have been given to man. The 
protection should not be such as to press upon vessels 
or impede the natural movement of the neck. In cold 
winds, the space about the neck may afford too free 
entrance for wind over the chest, and so it is wise to 
have a small silk or woolen handkerchief to place tem- 
porarily around it. But for general use, there is much 
to be said against neckcloths which are wrapped about 
the neck. 
12. The covering of the rest of the body in a climate 
subject to many changes, in which, by means of trans- 
portation, we are rapidly exposed to great changes of the 
latitude and longitude, becomes a most important con- 
sideration. Besides usual clothing, overcoats, shawls, and 
blankets, for adjusting ourselves to changes, are very 
valuable. 
It is well agreed, both from experiment and experi- 
ence, that woolen, or woolen and cotton, so mixed as not 
unduly to decrease the porosity or obstruct the air, 
and to combine lightness and non-contractility, are de- 138 
Hygiene. 
sirable. We must learn to adjust the undersuit to our 
needs, and not hesitate to make frequent changes, if 
variations of exposure require it. 
No part of the body below the neck should be with- 
out protection, in summer and winter. In the winter, it 
is a question of warmth; in summer, it is to have an 
absorbent for the perspiration, and to protect from the 
changes which are common between noon and midnight. 
Often the thinnest and finest forms of merino are best in 
summer, and are not to be dispensed with. Compensation 
can be had by having the more exterior garments light 
or thick, as may be needed. Those who are susceptible to 
change get much advantage from a double undersuit, 
the inner garments being much the thinner and finer. 
The socks are better if made partly of wool. A thinner 
inside sock is often worn with benefit. 
13. Great advantage for cleanliness and health is ob- 
tained by having both a night and day undersuit, so that 
one can be refreshed while the other is worn. Soldiers 
or others not well provided or situated for other changes 
find a double suit, thus used, much better than the con- 
tinued use of the same suit in succession. In India, the 
English soldiers often wear a double fold of flannel around 
the abdomen, which is called a cholera-belt. In washing 
clothing containing much wool, it should be put in 
hot soap-suds, and rinsed in cold water, without much 
rubbing, and dried without wringing. 
14. As the question of excessive or defective cover- 
ing is a relative one, it is much better to announce 
principles than to designate precise weight or amount. 
The usual weight of clothing for a soldier, without over- 
coat or boots, is stated at ten pounds. Clothing a Protection for Health. 
139 
Not much need be said of linen or muslin as the 
next covering. These are not objectionable, unless so 
thickly starched as to he too impervious or too rough. 
They give slight additional protection. We have already 
noted these in comparison with wool and with cotton of 
different texture. 
Having protected the skin with inner garments, chosen 
on the principles here discussed, it matters comparatively 
little what form the other coverings have, except that 
they are to be made of materials which will be an ad- 
ditional protection, and so arranged as not to give an 
unequal temperature. Thus there is no good hygienic 
reason for the covering of the body with pantaloons, 
vest, and coat, and then, as in a dress-suit, leaving the 
whole front with an open breast. Yet if it must be done, 
let some under garment make up for the opening. 
15. Of all these coverings, the waistcoat is the most 
important. If made of wool, or of mixed wool and 
cotton, if as thick on the back as at the front, and if 
closing in front to a point where it is joined by a woolen 
or silk scarf of about the same capacity for retaining 
heat, we have the article of dress next in importance 
to the undersuit. It incloses the organs which in their 
relation to the atmosphere are more vital than any 
others. All females should have a corresponding cov- 
ering in some form which will not prevent any outside 
form of appearance or adornment which may be desired. 
Let dress and taste have their sway, if only the body, 
more precious than either, has proper protection. 
16. All other forms of clothing, except those to which 
we have alluded, are to be such additions as will not in- 
terfere with action or protection. Coats, overcoats, dresses, 140 
Hygiene. 
are all to be studied with the same general view. The 
chief danger as to these is from the undue amount, or 
the mode of adjustment. While the shoulders and the 
hips are both adapted for the bearing of some additional 
weight, it should be not so great as to be burdensome, 
and not such as unduly to impede motion. A narrow 
and slipping suspender or arm-loop is quite different 
from one of moderate elasticity, so joined with its oppo- 
site, if need be, upon the back as to afford an easy up- 
holding. A series of small cords about the waist, and 
a weight of several unnecessary pounds, may be a great 
embarrassment as a load, or as respects motion. The 
shoulders and the hips should each bear a part. Dress 
can be so made that the support is divided. There 
are many reasons why the female dress should receive 
the careful consideration of those who are not easily led 
to advocate grotesque costumes, but who really believe 
that when a hygienic demand is made apparent, dress 
and taste will succeed in conforming itself thereto. 
The principles of physical science and art, which are 
so much at the basis of all practical hygiene, are teach- 
ing us how it is possible to distribute the weight of the 
lower garments, to make them flexible, yet firm enough 
not to embarrass locomotion, and with the addition of the 
close and indispensable under-garments to give a pro- 
tection consistent both with health and taste. No one 
who desires vigor can afford to overlook the principles 
which underlie dress as a comfort and health as well 
as beauty. Much evil has undoubtedly arisen from an 
undue pressure of dress over the chest and abdomen. 
17. The use of bands to fasten sleeves or stockings is 
also recognized as doing much harm, unless they are Clothing as a Protection for Health. 
141 
more elastic and less close fitting than many bands 
having the name of elastics. It is deplorable to find 
how often varicose veins and ulcers and enfeebled or 
diseased limbs have resulted from this cause. Those 
of the manual labor vocations especially suffer from 
various forms of hands and bandages used to keep 
garments on or in their places. Where varicose veins 
have been produced, early attention should be given to 
securing elastic stockings or other means of artificial 
pressure. 
18. The protection of the feet is especially indicated 
because they are apt to become cold whenever there is 
much languor of circulation, and to become cold or wet 
by exposure. We have already alluded to the fact that 
not enough care is taken of the foot, so as, by washing, 
oiling, rubbing, and properly fitting coverings to it, to 
give it the advantage of a uniform healthful condition. 
After the clothing which we give to it, in common with 
the rest of the body, we add leather, because, if well pre- 
pared, it is soft and porous, and it also has some firmness 
for impact, and retains heat. In very windy climates, 
coats are made of it, and it is much used as temporary 
outside coverings. In the coldest nights, the Anatolian 
shepherds lie out in their sheepskin coat and hood 
without injury, though unprotected men are frozen to 
death. Judged by the standard of hygienic clothing, it 
must be claimed that many thicknesses of leather are 
not desirable. Neither should a leather, covered with an 
impermeable coating, be worn continuously, however 
desirable it may be, for a time, to keep the feet from 
getting wet. It is but little better to wet the feet by 
retained perspiration, or interrupted evaporation, than 142 
Hygiene. 
by exposure to outside moisture; a very impermeable 
leather is therefore objectionable. As boots and shoes, 
if old and long worn, are soiled by the organic par- 
ticles from the feet, inside disinfection and drying are 
often desirable. 
19. Waterproof Clothing. — This principle as to the 
use of leather applies to all waterproof clothing. Because 
it protects from rain and wind it is often valuable for 
use amid exposure. But because of its interference with 
temperature, and especially as causing condensation and 
retention of perspiration, it is not a good permanent 
clothing. The effect is somewhat modified when the 
waterproof has a woolen lining. For temporary use this 
kind of clothing is valuable. The same applies to the 
use of rubbers for the feet. When india-rubber boots 
are worn a day or more at a time, it is best to have soft 
woolen or chamois sandals to wear within them. In- 
dividuals differ much as to their readiness of perspira- 
tion, and especially as to that of the feet. Where rubbers 
are found to produce moisture of the socks and feet, 
they had better be avoided, except during actual storms. 
Much depends as to the use of waterproof clothing 
on the condition of atmosphere. In cold storms it can 
be worn much longer and more safely than when the 
weather is warm and the air highly charged with 
moisture. 
20. Thus it is seen that the whole subject of clothing 
has very important hygienic relations, — such as have 
their basis in the ascertained facts as to the character, 
make, and color of fabrics, and as to the physiology of 
life. It is a matter in which there must be compensation 
and adjustment to the varying conditions of ourselves and Clothing as a Protection to Health. 
143 
the atmosphere about us. But these facts aid much 
in guiding us. Gloves and coverings for the wrist need 
only the same principles to guide as those for other ex- 
posed parts. In very cold weather we economize heat by 
closing all apertures for its escape. So if the dress about 
the wrists or feet is closed, there is less access for currents 
of air and less egress of heat. 
21. It is to be remembered that about one-third of life 
is spent in bed, and our clothing, while in it, is a matter 
of great importance. The same principles presented as 
to day-clotliing apply here, except that there is no need 
of such as protects from wind and rain. The linen or 
muslin sheet is not objectionable if it has above or 
beneath it the woolen blanket. Feathers and hair-beds 
are good, if the material is always nicely kept. If not, 
the dependence should be more upon spring-beds and 
blankets. It is well to bear in mind that when in bed 
in a horizontal position the constant flow of air around 
our bodies causes the strongest currents to be ascending 
toward the head. So, if the air is impure by reason of 
any want of care or of change of under-garments, the 
lungs receive more than their share of organic matter. 
Cleanliness and warmth of clothing without undue 
weight, and such extra clothing as can be put on or 
laid off at pleasure, are very important for the bed- 
room. Heated bed-rooms are seldom needed for the young, 
and there should always be some arrangement by which 
fresh air can be admitted without draught. Foul air al- 
ways makes demand for more clothing. 
22. Habitations. — Our next artificial method of add- 
ing to the covering afforded by the skin and by clothing 
is that of a habitation or dwelling-house. It is an effort 144 
Hygiene. 
to adjust ourselves to the world about us by providing 
another external means of covering. It is only an ad- 
dition to clothing, so that where it suffices no house- 
covering is sought. Where more is needed, the provision 
ranges through all degrees, from that of the occasional 
shelter against wind or rain or sunshine to that against 
cold. 
23. As with clothing, so with houses; those are the 
best which give us the outside air, delivered from those 
extremes which are found uncomfortable or unbearable. 
Thus, if we could be put in houses whose walls no air 
could penetrate, we would be much in the same plight 
as if our skins were covered with varnish, or our con- 
stant garments were all water and air proof. It is be- 
cause bricks are porous to air that they are so much 
used in building. If the bricks are soaked through with 
water, there is no room for air in the spaces. Then 
they become air-tight, and by reason of dampness and 
lack of air we could not live in such a house. 
The questions, then, as to a good house are: How shall 
we build it so as to secure purity of air in it? how shall 
we adapt it for proper coolness when it is too hot out of 
doors, and for proper heat when it is too cold without? 
24. Our first attention must be to the ground upon 
which it is built. It must be so porous by nature or 
so kept by art that air may permeate that part of it on 
which the house rests. If there is undue water it will 
not only abstract heat, but it will be drawn into the 
building material and help to shut out pure air of proper 
temperature. Therefore the person seeking this additional 
clothing needs a dry soil, and for a reason similar to that 
for which he needs a dry garment, lienee underdrain- Clothing as a Protection to Health. 
145 
ing and cement floors and sides, and sometimes a damp 
course of slate or asphalt, after the foundation is above 
the ground, are necessary in order to protect the build- 
ing material from sucking up water instead of taking in 
air. A drainage .toward the house, loose soil about the 
building, the discharge of roof-leaders on the ground, and 
the shutting out of sunlight, are among the causes which 
often add to the dampness of the ground, and render 
houses damp and unhealthy. It is because painted and 
papered walls serve to prevent the circulation of air from 
without and within, through the bricks, that they are 
not as healthy as walls of different finish. But where 
the ground and walls are very dry, there will still be cir- 
culation, and the evil is trivial. Not so, however, where 
there is great dampness, or where new paper is put on 
without removing the old. 
25. From what has been already said, we know that 
clothing that becomes full of dust or dirt, or sealed 
up by being greasy, is not fit for use, because the air 
is thus in part excluded, and what there is is laden with 
particles and gases that hasten to decomposition. 
For just the same reasons, the house that is full of dust 
or decaying matter in the walls, or in the air of the 
rooms, also needs to be washed and aired. The reasons 
for clean houses and thorough housekeeping are the same 
as the reasons for clean clothes and a clean skin. The 
care of dwellings, school-rooms, and all houses, therefore, 
requires all the details of the most thorough airing and 
cleansing, and all facilities for securing them. 
26. As by virtue of the necessities of civilized and do- 
mestic life, there are produced in the house many sources 
of foul air, we are to be constantly on the alert to 146 
Hygiene. 
remove these or to compensate therefor. We thus study 
to have the dwelling permeated by pure air, so tem- 
pered in its velocity of movement as not to occasion 
undue draught, of such temperature as not to chill, and 
of such quantity as will dilute the air which is constantly 
being deteriorated; also there is need to provide means 
for letting out the air of the room so that constant 
entrance, dilution, and displacement may go on. 
27. As to school-houses, and all public assembly- 
rooms, we are to remember that in these we have even 
greater demands for purity of air; and yet by reason of 
numbers, and various other circumstances, it is more 
difficult to obtain the needed supply. How this is to 
be done we shall have occasion more fully to discuss 
when speaking of Ventilation and Heating. At 
present, we only have occasion to note the house as a 
form of clothing, and as aiding the body and its cover- 
ing, the skin, in the adjustment of the world without 
to the world within. Chapter IX. 
THE BLOOD AND ITS CIRCULATION. 
AS the chief function of the lungs is to affect the 
blood, we next come to inquire as to it, and the 
force and mode of its circulation. The minute capilla- 
ries (Lat. capillus, a hair), or blood-paths, with which 
we have had to deal in the lungs are but the terminal 
fibrillse of an immense system, having its origin at a 
central organ. These minute tubes enlarge into others 
known as arteries and veins, the one class of vessels 
carrying blood from the heart and the other class dis- 
tributing it thereto. As we shall hereafter see, when 
speaking of Foods, these vessels are the carriers of 
blood, and of the blood material which is gathered from 
the digestive canal after it has been duly prepared. The 
mode by which it is gathered and enters the circulation 
we shall see in our study of the digestive apparatus. 
2. The shape and position of the heart are best illus- 
trated by presenting it as located in relation to the lungs. 
See diagram, p. 156. 
A section of it, on the next page, as seen from the front, 
will give some idea of its inner structure. It is located in 
the central part of the thorax, or cavity under the lower 
two-thirds of the sternum, or breast-bone. Its apex or 
lower end extends out beyond the breast-bone between 
the left fifth and sixth ribs, and can be felt by its beat 
about two and one-half inches to the left of the median 
147 148 
Hygiene. 
line. In a full-grown man it is about five inches long, 
three and one-half inches broad, and two and one-half 
inches thick, and weighs about ten ounces. It is a 
rounded conical organ, the shape of which can be filled 
Right Pulmonary Artery. 
Arch of 
Aorta. 
Left Pulmonary Artery, 
Upper Vena Cava. 
Left Pulmonary Veins. 
Right Pulmonary Veins. 
Left Auricle. 
Mitral Valve. 
Tricuspid Valve. 
Lower Vena Cava. 
Right Auricle. 
• Lett Ventricle. 
Right Ventricle. 
Septum Ventriculorum.* 
’Descending Aorta. 
FIG. XVII.—Section of the Human Heart. Frontal aspect 
out from the diagram. It is divided by muscular walls 
into four cavities, the two upper ones being called auri- 
cles and the two lower ventricles. It is more significantly 
spoken of as the right and the left heart. 
3. The right auricle receives into it the blood which 
flows to it from the great veins, and by its contraction 
passes it on into the right ventricle. The ventricle in 
contracting forces the blood through the large vessels 
called the pulmonary arteries. This right heart is, there- 
fore, sometimes called the pulmonic heart. The dark or 
venous blood which has been gathered from the whole 
system is forced by the right heart into the lungs; it is 
then spread out over a vast network of capillaries, or 
small blood-vessels, as before noted, through the thin The Blood and its Circulation. 
149 
walls of which it comes in contact with the inbreathed 
atmospheric air. Thus it parts with those portions of 
its contents which are no longer of use, and, receiving 
oxygen from the air, is converted into red or arterial 
blood. 
4. This blood passes from the lungs by its pulmonary 
vessels to the left auricle of the heart. This contracts 
and sends it into the left ventricle. This is a cavity with 
strong muscles and great propelling pow7er, and throws 
the blood with great force through the semi-lunar valves 
into the large tube known as the aorta. From it, through 
the branching vessels, it is distributed to the whole sys- 
tem. The impulse it thus receives is conveyed to all the 
arteries, and is called their pulsation. We generally feel 
for it at the w7rist, and call it the pulse. The preceding 
diagram sufficiently marks the general location of the 
various parts of the heart. 
5. The right auricle of the heart is separated from the 
right ventricle by a valve known as the tricuspid valve. 
The left auricle is separated from the left ventricle by a 
valve known as the mitral valve. The ventricles are 
a little larger than the auricles, and each is capable of 
containing from four to five ounces of blood. 
It is thus seen that the human system contains a per- 
fect apparatus for the distribution of the blood to every 
bone, muscle, and fiber of the system, as also a method 
for securing its purification. The fluid itself may be said 
to have tw7o bases of supply, together w7ith associate or 
intermediate provisions for the removal of all foreign 
or used-up or deleterious materials. 
6. The food, through the alimentary canal, gives the 
primary supply, while the same canal, which imparts the 150 
Hygiene. 
food, has collateral to it various separators which remove 
and discharge extraneous material. So also the heart 
has its way of sending the blood up to the lungs, that 
it may there be rid of materials no longer wanted, and 
also receive a supply of life-giving oxygen to do its 
work in the various changes which it secures throughout 
the system. The amount of blood on an average is cal- 
culated to be about one-thirteenth of the weight of the 
body, so that in a person weighing one hundred and 
thirty pounds it would be ten pounds. 
7. We now come naturally to inquire what blood is, 
and how, as thus distributed, it imparts life and vigor 
to the human system. As we look at it, it seems to be 
merely a reddish fluid, varying from red to dark blue, 
accordingly as it has come from arteries or capillaries 
or veins. If, however, some is drawn, it soon becomes 
jelly-like. After a little, a clear yellowish watery-look- 
ing fluid appears on the surface and about the edge of 
the vessel, while the central part is a red semi-solid 
mass. The liquid we call the serum of the blood, and 
the more solid mass the clot. As we come to examine 
the clot, we find it made up of various minute corpus- 
cles, or minute rounded or oval bodies, and that they 
are held together by fibrin, a substance with which we 
will come to be familiar in the study of foods. The 
fibrin, too, we find to have originally belonged with the 
serum, and with it to have made what is known as the 
liquor sanguinis, or plasma. 
8. When the corpuscles come to he studied they are 
found to be of two varieties, known as the red corpuscles 
and the colorless or whites corpuscles. 
The former are much the more numerous, while the 
latter are somewhat the larger. The Blood and its Circulation. 
151 
The red corpuscles are flattened, circular discs aver- 
aging 32V0 °f an inch in diameter. The colorless cor- 
puscles average 2 5V0 °f an inch in diameter. They 
form what is called a nucleated cell, from which it is 
quite certain that in some way the red corpuscles are 
derived. 
9. Considered chemically, the blood is an alkaline 
fluid, consisting of water, of solid and gaseous matters. 
“The proportions of these several constituents vary 
according to age, sex, and condition, but the following 
statement holds good on the average: 
“ In every 100 parts of the blood there are 79 parts 
of water and 21 parts of dry solids; in other words, 
the water and the solids of the blood stand to one 
another in about the same proportion as the nitrogen 
and the oxygen of the air. Roughly speaking, one- 
quarter of the blood is dry, solid matter; three-quarters 
water. Of the 21 parts of dry solids, 12 (equal four- 
sevenths) belong to the corpuscles. The remaining 9, or 
about two-thirds (equal to two-sevenths, or the whole 
solid matter), is albumen, a substance like white of egg, 
coagulating by heat, and one-third (equal one-seventh 
of the whole solid matter) a mixture of saline, fatty, 
saccharine matters, sundry products of the waste of the 
body, and fibrin. 
10. “ The total quantity of gaseous matter contained 
in blood is equal to rather less than half the volume 
of the blood; that is to say, 100 cubic inches of blood 
will contain rather less than 50 cubic inches of gases. 
These gaseous matters are carbonic acid, oxygen, and 
nitrogen; or, in other words, the same gases as those 
which exist in the atmosphere, but in totally different 152 
Hygiene. 
proportions; for whereas air contains nearly three-fourths 
nitrogen, one-fourth oxygen, and a mere trace of car- 
bonic acid, the average composition of the blood gases 
is nearly two-thirds carbonic acid, rather less than one- 
third oxygen, and one-tenth nitrogen. 
11. “ It is important to observe that blood contains 
much more oxygen gas than could be held in solution 
by pure water at the same temperature and pressure. 
This power of holding oxygen appears in some way to 
depend upon the corpuscles, firstly, because mere serum 
has greater power of absorbing oxygen than the pure 
water has; and, secondly, because red corpuscles sus- 
pended in water, instead of serum, absorb oxygen very 
readily. The oxygen thus held by the red corpuscles 
is readily given up by them for purposes of oxidation, 
and indeed can be removed from them by means of 
a mercurial gas-pump. It would appear that the con- 
nection between the oxygen and the red corpuscles is 
of a peculiar nature, being a sort of loose chemical 
combination with one of their constituents, that constitu- 
ent being the haemoglobin; for solutions of haemoglobin 
behave towards oxygen exactly as blood does. 
12. “ The corpuscles differ chemically from the plasma, 
in containing a large proportion of the fats and phos- 
phates, all the iron and almost all the potash of the 
blood; while the plasma, on the other hand, contains by 
far the greater part of the chlorine and the soda. 
“ The blood of adults contains a larger proportion 
of solid constituents than that of children, and that of 
men more than that of women; but the difference of sex 
is hardly at all exhibited by persons of flabby, or what 
is called lymphatic, constitution. Tiie Blood and its Circulation. 
153 
13. “ The total quantity of blood contained in the body 
varies at different times, and the precise ascertainment 
of its amount is very difficult. It may probably be 
estimated, on the average, at not less than one-thirteentli 
of the weight of the body. 
“ The function of the blood is to supply nourishment, 
too, and take away waste matters from all parts of the 
body. It is absolutely essential to the life of every part 
of the body that it should be in such relation with a 
current of blood, that matters can pass freely from the 
blood to it, and from it to the blood, by transudation 
through the walls of the vessels in which the blood is 
contained.” 
The circulation of the blood is affected or embarrassed 
in various ways. 
Persons subject to fright or frequent excitement are 
likely eventually to have some trouble of the heart or 
the larger blood-vessels. It is true that the heart is 
made to endure many variations, but frequent and rapid 
changes of heart-beat are to be avoided. 
14. The effects of stimulants upon the circulation need 
careful consideration. In the study of Drinks and Con- 
diments we will have occasion to notice their dietetic 
effects as allied with their effects on the circulation. 
There is no effect of alcohol more insidious than that 
produced by the nervous thrill it imparts to the action of 
the heart, and which is propagated all along the various 
vessels of the circulation. Even the temporary benefit 
derived from it, in cases of collapse, is most forcible 
evidence that its frequent or continued use is attended 
with most disturbing results. 
The minute enlarged capillaries often seen upon the 154 
Hygiene. 
face, and the general redness of countenance produced 
by alcohol, in many who are regarded as temperate in 
its use, are the forcible declaration, that to the very tip- 
ends of the circulating system it is capable of suspend- 
ing contractile action, of paralyzing vaso-motor nerves, of 
weakening the caliber of the vessels, and of producing 
permanent engorgement or congestion in them. If this 
is true of the minute vessels of the face, it is equally true 
of those of the lungs, the liver, the kidneys, and other 
organs. When it is remembered that most of the vital 
organs are made up of millions of these little arterioles 
and veins, what takes place on the skin is the demon- 
stration of far-reaching and abiding impairment of all 
vascular organs. 
15. In different persons different organs seem to feel 
the severity of the disturbance, but all are more or less 
weakened. Authorities may differ in their estimate of 
causes which have produced embarrassing and finally 
fatal changes in various secreting and excreting organs, 
but we believe no one has yet been found to dispute 
the unrivalled capacity of alcohol to produce irritative and 
degenerative changes in the minute capillary circulation on 
which the integrity and ability of the vital organs de- 
pend. This does not absolutely retire it from use in the 
hands of the skilled physician in emergencies of disease, 
any more than it does opium, belladonna, or corrosive 
sublimate, but it does certify that alcohol is the most 
riskful of drinks, in all that relates to the circulation of 
the blood in those organs whose vitality and function 
depends on the perfectness of their capillary circulation. 
It is essentially a disturber of the rhythm and the 
function of the blood-flow. The Blood and its Circulation. 
155 
16. The blood is found to contain all the material 
needed for the nourishment of the entire system, as 
derived from ordinary food. Intermediate between it 
and the food we have a fluid that is known as lymph. 
This is contained in the lymphatic vessels. These are 
the vessels which absorb chyle from the digestive track. 
This, mingling with the juice peculiar to the lymphatics, 
is conveyed into the thoracic duct, and so into the blood 
current. The lymph-vessels have, in their course, small 
solid, oval, glandular bodies, varying in size from a 
millet-seed to an almond, through which they pass on 
their way to the thoracic duct. The chief of these are 
found in the neck, the axilla, the groin, and the mesen- 
tery, and are called glands. 
All parts of the body which have capillaries, except 
perhaps the bones, brain, and spinal cord, eyeballs, 
cartilages, and tendons, have also these lymphatic vessels 
intermingling with the blood-carrying vessels, though 
not in direct communication. They are not supplied by 
any large vessels bringing food to them, but open into 
vessels or trunks which carry fluid from them. These 
various trunks center into and ramify through the lym- 
phatic glands. Finally, most of these lymphatic tubes, 
after thus twisting about amid glands, pour their liquid 
into the thoracic duct, which runs up along the spinal 
column and empties its contents into the blood circula- 
tion at the junction of the left jugular and sub-clavian 
veins. The lymph is blood minus its red corpuscles, and 
becomes changed as it mingles with the current. 
17. The spleen, a small spongy organ to the left of the 
stomach, is regarded as having important relations to 
the blood and the lymph circulation, but these are not 156 
Hygiene. 
as yet so known as to bring it within the reach of 
hygienic care. 
18. The blood is being constantly added to by the 
life-supporting constituents it is constantly deriving from 
foods as well as from the air, while it is also the receiver 
of material from all parts of the system. It has been 
compared to a river, the nature of the contents of which 
is largely determined by the nature of the head-waters 
and of the animals which swim in it; but which is also 
very much affected by the soil over which it flows, by the 
water-weeds which cover its banks, and by affluents from 
distant regions; by irrigation-works which are supplied 
from it, by drain-pipes which flow into it. Even the 
change from venous to arterial blood does not take place 
in the lungs only, but in most parts of the body, the skin 
especially being the analogue of the lungs. 
There is a real difference in the quality of blood, as 
the body is well or illy nourished, as well as from the 
infusion into it of deleterious substances. By compar- 
ing the composition of foods, of the blood and of the 
various tissues, we are able to arrive at quite definite 
conclusions as to the demands of the human system. 
19. From what we have seen of the course of the 
blood and of its uses, it is evident that we should not, by 
undue pressure, interfere with its natural flow. Exercise 
strongly determines its activity of flow. We are so con- 
stituted that, if we live indolent lives, or if the skin 
is so obstructed as to interfere with its natural action, 
the same amount of blood will not find its way into 
the minute vessels which form the boundary between 
ourselves and the world about us. As the drawing of 
blood to the surface relieves internal congestion, so The Blood and its Circulation. 
157 
those who do not properly use the limbs and muscles 
have the blood too much centered in or about the in- 
ternal organs. 
20. The hygiene of the blood requires proper food, ex- 
ercise, cleanliness, right living, and sound organs, and 
then the system will not fail to make use of its natural 
powers of construction, elimination, and repair. The 
importance of a natural distribution of blood is seen 
when, by some sudden shock of the system or failure 
of heart-action, faintness is produced. The heart be- 
comes disturbed in its action, and the person turns 
pale, and will fall unless there is speedy relief. When 
a person suddenly turns pale or faints, he should be at 
once put in a reclining posture at full length. Pure, 
fresh air should be secured, and water sprinkled in the 
face. A drink of water, or the smell of vinegar, am- 
monia, or other strong scent, will often aid in recovery. 
All these are useful, because they aid to restore the 
proper circulation by a quick impression made on the 
nervous system, and transmitted to the blood-vessels. 
Clothing, if tight, should be loosened, and especially 
about the waist and neck, to remove all pressure from 
the blood-vessels. 
21. Faintness illustrates how the circulation of the 
blood is connected with the nervous system. Minute 
nerves, known as the nerves of the vaso-motor system, 
supply all the blood-vessels, and the tubes are more or 
less responsive to nervous impressions made upon the 
senses. Thus, a man once reaching up to hang a piece 
of meat caught his arm violently on the hook and 
fainted, but when the coat was taken off it was found 
that the flesh had not been wounded. We find, too, 158 
Hygiene. 
how even the nervous and circulatory system can be 
educated. The person who tries to resist faintness is 
not so apt to faint, Many a person who at first faints 
at the sight of blood becomes so accustomed to it as 
not to be affected by it. 
22. Nose-bleed generally denotes either thinness of 
blood or a tendency of too much blood to a particular 
part. It sometimes results from the wounding of some 
small vessel by pricking, or from an irritation of the nose 
in some way. When from one nostril, it is often easily 
stopped by closing that nostril with the ball of the 
thumb and inbreathing with force through the other. 
Cold applied to the head and neck, or the snuffing of a 
little alum or alum-water up the nose, is often efficacious. 
When there is bleeding from a wound, bring the sides 
of the wound closely together, and then wrap it tightly 
about with a bandage until a physician comes. 
23. If an artery is wounded, tie a handkerchief 
tightly above the wound, and twist it about with a lead- 
pencil, or larger stick, until the surgeon arrives. We 
have known all sorts of things, from salves and starches 
down to spirits and tobacco, put into wounds to stop 
bleeding, or to heal them; but beyond a little oil, to 
keep the bandage from sticking, just over the cut, such 
applications are not necessary. Often scars or sores 
come from the neglect of cuts, which if neatly joined 
would heal as it is called by first intention. When 
there is hemorrhage from the throat or lungs, perfect 
rest, pure air, and a mustard-plaster to the chest, and 
the use of ice or a strong solution of salt, or a few 
drops of turpentine on sugar, are the best measures 
until further aid can be had. Chapter X. 
THE LUNGS, AND THEIR RELATION TO HEALTH. 
NEXT to the skin, in its contact with the outside 
world, we come to consider the lungs and their 
office work as related to the maintenance of health. 
We are so constituted that the blood, which is the 
vehicle of life, in its circulation through the system 
must be spread out, as it were, in sheets over surfaces 
against which air is let in, so that it may receive oxy- 
gen from the air, and give up carbonic acid, gases, and 
particles of organic matter, which the system must get 
rid of by such means. As air with its oxygen is the 
only mixture of gases fitted for this purpose, it must 
have free access to the organs in which the chief ap- 
paratus for aerating the blood is located. This consists 
of two organs known as the lungs. They are situated 
within the ribs on each side of the median line of the 
body. They are formed so as to present, in the smallest 
space, a very extensive surface of blood to a very large 
surface of air. A sheet of air is thus spread alongside 
of a sheet of blood with a membrane between, so thin 
that oxygen, carbonic acid, and other ingredients, inter- 
change freely. 
2. The lungs are two large, spongy, elastic organs 
occupying the right and left sides of the thorax, or 
chest. The chest includes the back as far down as the 
lower ribs. They consist of lobes which are divided into 
159 160 
Hygiene. 
lobules, or small sacs, each of which is a little lung 
of itself. Under the stimulus of air and blood, these 
air lobules, or vesicles, expand and contract, and do 
their work of interchange. The right lung is a little 
larger than the left, and has three lobes, while the left 
Right Jugular Vein. 
Left Jugular Vein. 
Carotid Arteries. 
,Carotid Arteries. 
Trachea. 
Aorta. 
Subclavian Vessels. 
Bronchi. 
Subclavian Vessels., 
Bronchi... 
Pulmonary 
Veins. 
Pulmonary Veins. 
Right Auricle. 
Left Auricle. 
[■Left Lung. 
Heart. 
Right Ventricle. 
Right Lung. 
Vena Cava 
Inferior. 
Left Ventricle. 
FIG. XVIII. — The Heart, Large Vessels, and Lungs. 
has but two. The two lungs weigh about twenty-four 
ounces. Their relative position is shown by the figure. 
When healthy, the lung is so light, and has so much 
air in it, that it floats in water, and is the only one of 
the viscera that does. These two air-sponges, although The Lungs as Belated to Health. 
161 
contained in so small a space, have a very large capa- 
city. Over one thousand gallons of air pass through 
them each day, and in active exercise they may be 
made to use two thousand gallons per day. To dis- 
tribute the air to these air lobules a system of tubes 
is necessary. 
3. The system begins with the trachea (Gr. rpaivg, 
rough), or windpipe. This is a membranous tube, kept 
constantly open by from sixteen to twenty cartilages 
which extend around about two-thirds of its circumfer- 
Larynx. 
Trachea. 
Right Bronchm 
Bronchial Tube. 
Left Lung. 
Ultimate Bronchial 
Tubes. 
PIG. XIX.— Air Tubes of Right Lung exposed, and Left Lung. 
ence. It is about four and one-half inches long, and 
three-fourths of an inch in diameter. Beginning at the 
larynx, or voice-box, it extends down to opposite the 162 
Hygiene. 
third dorsal vertebrae, where it divides into two branches, 
which, in their turn, divide into multitudes of bronchial 
tubes. 
This system of tubes is known as the bronchi or 
bronchial portion of the lungs. The subdivision is well 
shown in the preceding plate. Bronchitis is inflamma- 
tion of these tubes. The ultimate or smallest bronchial 
tubes terminate in infundibula, or air-sacs, which are 
minute conical expansions of the ultimate tubes about 
of an inch in diameter. Their walls are, as it were, 
puffed out like tucks or minute pouches or saccules, 
and are called air-cells. Their number is not less than 
600,000,000. 
4. These air-cells are about 2 0 0 °f an inch in diameter. 
Between these vesicles are intercellular passages, in which 
a delicate yellow, elastic tissue gives support, and a rub- 
ber-like readiness of motion. The respiratory surface 
afforded in the two lungs is not less than 1400 square 
feet. On the outside, and just alongside of all these vesi- 
cles of air, is a capillary network of minute blood-vessels, 
almost countless in numbers, and varying from 3oVg- 
of an inch in diameter to smaller sizes. The heart and 
circulation, as controlled by the nervous energy, causes 
the fountain of blood from the entire system to be dis- 
tributed in these, and so to come alongside of the fresh, 
pure air, and make that interchange on which life de- 
pends. Breathing is the process by which pure air 
is drawn from the outer world into the trachea or 
windpipe through the nose and mouth. Entering these 
minute air-cells it gives up its oxygen to the capillary 
circulation, and receives in its stead carbonic acid gas, 
watery vapor, and all gases or decayable organic matter 
that can thus escape by expiration. The Lungs as Related to Health. 
163 
5. The heat of the expired air is about 98°. About 
8G0 cubic feet of air is thus passed into the lungs, in 
ordinary quiet life, in the course of each 24 hours. 
About 10,000 grains, or 18 cubic feet, of oxygen is thus 
given up, and about 12,000 grains, or over 21 cubic feet, 
of carbonic acid removed. With it is given off about 
9 ounces of watery vapor, and a varying amount of 
epithelial cells and other highly decomposable animal 
matter. All of the air vesicles of the lungs are not 
used at each inspiration or expiration, but there is a 
reserve for such times of exertion as require the in- 
halation of a larger amount of air. 
6. But even where there is rapid expiration, consid- 
erable air is left in the lungs. That which passes in 
and out in ordinary breathing is sometimes called the 
tidal air. After an ordinary inspiration, there is about 
200 cubic inches of air in the lungs. Only from 20 to 
30 cubic inches passes in or out at each breathing. 
As this residual air is always present, it forms an 
atmosphere in the lung, into which the carbonic acid 
and other used-up materials are infused, as also the 
pure air which is inhaled. It thus becomes the medium 
of exchange between the pure and the impure air. If 
there is disease of any kind in the lungs, it becomes still 
more befouled, and may need special antiseptics and 
disinfectants to be added to the inbreathed air. Deep 
inspirations of pure, cool air are of much value. 
7. It is important to bear in mind that the carbonic 
acid given off from the lungs is not formed by the sud- 
den combustion of the oxygen breathed in with the car- 
bon in the capillaries, but the carbonic acid exists in the 
venous blood as it comes to the lungs, and the oxygen 164 
Hygiene. 
inhaled is merely absorbed and carried onward, in a 
condensed state, with the blood current, probably only 
in solution. 
Blood contains much more oxygen gas than could be 
held in solution by water at the same pressure and 
temperature. According to Magnus, the blood holds 
two and one-lialf times as much oxygen as is held 
by pure water. 
8. As our design is always to add only the purest 
air, or what Linnaeus calls habitable air, to this volume 
of residual air, we easily see what a mistake it is if the 
air breathed in is itself impure. The great strife of 
physical life is to secure pure air. 
If in some way the air has been deprived of its oxy- 
gen, or any part of it, it fails of its first, great purpose; 
if in its stead it is already laden with carbonic acid, or 
dust, or foul gases, or organic particles, it is so far 
unfitted to bring back its quota of foulness from the 
residual air of the lungs. 
Impure air is far more a cause of ill-health than most 
imagine. It is not merely that various lung diseases are 
caused thereby. The venous blood, laden with its used- 
up material, ready to be delivered and exchanged for 
the vital oxygen it needs, is not clarified as it should be, 
and the vessels are compelled to carry back again some 
of the used-up material. To some extent, the whole 
system is devitalized. Were it not that the human sys- 
tem has great power of endurance and adjustment, and 
is able sometimes to transfer to other organs the work 
which should have been done in the organ designed for 
it, life would be in constant peril. 
As it is, health is often injured or vitally impaired The Lungs as Related to Health. 
165 
by such forced substitutions. The embarrassment may 
finally show itself in a diseased lung, or congestion of 
other organs, or impairment of function and a general 
waste of vigor. 
9. There is a sense in which pure air is as much a 
food as anything that is taken into the stomach. If we 
are deprived of it, there is a real want of nourishment. 
The food taken into the stomach cannot be so well ap- 
propriated, and the blood fails to be the distributer of 
vitality that it should be. The result is a general 
loss of vigor. Either because of unremoved material, or 
of local irritation, minute deposits of ill-organized parti- 
cles take place about the areoles of the lung in the form 
of tubercle, or the walls of the vesicles become thin and 
feeble, and hemorrhage occurs. Thus many a case of 
consumption is started. Deposit often takes place long 
before there is cough, or any of the signs of local im- 
pairment or constitutional disturbance. 
10. The act of respiration is accomplished by the elasti- 
city of the lungs and the mechanical arrangement of the 
thorax, or chest, in which they are contained. The elas- 
tic tissue of the air-cells is distended when the lungs are 
full, and then quickly contracts upon the air sufficiently 
to aid in expiration. The contractile power of the mus- 
cular walls of the bronchial tubes and the cilia, or hair- 
like plush upon the inner lining of these tubes, co-oper- 
ates with the expulsive movement of the air-cells to 
remove the air and any liquids or solids. 
This contractile and ciliary movement aids to remove 
all undue secretion, and is an additional aid in coughing, 
where the irritation is not too great. 
11. The chest walls form a wonderful mechanical appa- 166 
Hygiene. 
ratus for the reception and expulsion of air. The ribs 
are so attached to the vertebrae of the back-bone or 
spinal column as to be freely movable, and are so 
sloped toward the sternum or breast-bone as naturally to 
settle downward and forward. Crossing sets of muscles 
between the ribs are so arranged that the external in- 
tercostal muscles raise the chest while the internal 
intercostals depress it. Below the ribs, and between the 
lungs and the viscera of the abdomen, is a peculiar 
inner muscle, or set of fan-shaped muscles, called the 
diaphragm, which can co-operate in this action of the 
chest walls, or may remain quiet. 
Cartilage of Sternum. 
Inferior Vena 
Cava. 
(Esophagus. 
Costal 
Cartilage. 
Lowest Rib. 
Aorta. 
Pillars of Diaphragm. 
FIG. XX. —Showing the Diaphragm from the Abdominal side. 
This figure will give some idea of it. It separates 
the cavities of the thorax, and the abdomen, and so The Lungs as Related to Health. 
167 
forms the floor of the one and the roof of the other. 
Its mobility aids in the act of breathing. 
Although the two generally co-operate, we may have 
costal or chest respiration, or hold the chest nearly still, 
and have the respiration mostly conducted by the dia- 
phragm and abdomen, and so called diaphragmatic 
respiration. Usual, gentle respiration is aided by the 
movements of the diaphragm. 
12. The muscles of the abdomen also have an impor- 
tant service in connection with respiration. They much 
aid the action of the diaphragm and the chest, and are 
available, in various ways, as an aid during exertion. 
Usual respiration is from 13 to 15 times per minute, 
about 30 cubic inches of air being inspired and about 
the same amount expired. The mechanism of respira- 
tion is a little different in the two sexes. In men, the 
diaphragm and the abdominal muscles do the chief 
work, while in women the respiratory movement is 
mostly thoracic or costal. 
It has been necessary thus to note these facts as to 
the mechanism of respiration, because so many embar- 
rassments happen to this vital process. 
Curvature of the spine, even when slight, as often 
caused by a habit of dropping of one shoulder, or in 
other ways, mars not only the symmetry of form, but 
interferes with the breathing. Pressure in various 
forms on the ribs, the breast-bone, or the adjacent 
muscles, is a still more frequent embarrassment. It 
may occur from the mode of dress, where the chest-walls 
are too tightly bound for free and natural expansion, 
or where the waist is girt about with various cords 
or swaddling-bands. Children, women, and adult men, 168 
Hygiene. 
often suffer such embarrassments. Suspenders, if inelas- 
tic and often slipping from the shoulder, do not well 
distribute the weight. 
13. A waist and chest coat fitted to the real form may 
have sufficient stiffness to help support the clothing, 
which depends even more on properly adjusted shoul- 
der-straps. But, unfortunately, the more usual effort is 
to make the form fit its case. Many valuable improve- 
ments in chest or thorax dress are now secured, and it 
is either carelessness or perverseness to adopt injurious 
forms. Women are more dependent on chest breathing 
than men, and so should be even more careful not to 
impede the free and natural action of the chest. Un- 
trammeled breathing is of so much more importance 
than an ideal form produced by artificial compres- 
sion, that no one should attempt to sacrifice the former, 
especially as in the natural form of the body no mis- 
take has been made, either as to utility or comeliness. 
Posture is to the student a matter of no small im- 
portance. A chair sufficiently low, or a desk sufficiently 
high, or an occasional standing posture, will not only 
rest the muscles, but will aid much in the free play 
of the breathing apparatus. 
14. Where there is any defective capacity of the lungs, 
or where there is flatness of chest or deficiency of muscu- 
lar power, much benefit is often derived from exercise, or 
from gymnastic training under those who understand 
the way of accomplishing the object sought. There 
must be proper invigoration of the general system by 
good food and sleep, such exercise as gives play to the 
proper muscles and antagonizes errors of shape or habit, 
and such development of inspiration and expiration as The Lungs as Related to Health. 
169 
shall gradually increase the breathing capacity. Sudden 
efforts are never to be encouraged, but it is marvellous 
how, by proper drill and exercise, defects can be remedied 
and increased power secured. Physicians, and those who 
closely study returns as to the cause of death, aver that 
fully one-half of those who die between five and sixty 
years of age die from impure air or affections of the 
breathing apparatus. Parkes says that statistical in- 
quiries into mortality prove, beyond doubt, that of the 
causes of death which usually are in action, impurity of 
the air is the most important. 
15. Having defined pure air, and the relations of the 
lungs thereto, and how they are to be kept in working 
order, we pass next to notice how we are to protect them 
from impure air. If this be not done to a reasonable 
extent, no increase of capacity, and no riddance of undue 
pressure, will prepare them to receive a form of aerial 
supply for which they never were adapted or intended. 
First of all, in the great open, we sometimes need to 
guard them against certain dangers that may arise. It 
is to be remembered that the nose, which has no 
muscular apparatus to close it, is the extension of the 
trachea or windpipe, and is the natural aperture for the 
inflowing of air. It is true that the mouth is accessory, 
and in running or violent exercise, is available, just as 
are other parts of the body which are foreign to the 
essential act of breathing. 
An excellent little book was written by Catlin, the 
Indian antiquarian, with the title, “ Keep your mouth 
shut.” Its object was to show that the most prevalent 
cause of lung disease is the undue use of the mouth for 
breathing purposes. 170 
Hygiene. 
The nose is admirably arranged by its divided and 
complicated passages, its hairs, secretions, and membrane, 
and its mode of jointure with the larynx, for straining 
and warming the air, for which purposes the mouth has 
no arrangement. Bronchial irritation, and other lung 
disturbances, frequently happen from undue use of the 
mouth in the open air, from the habit of breathing 
through it or of sleeping with it open. 
16. In certain employments, where there is much dust, 
workmen are greatly benefited by keeping the mouth 
closed, and by aiding the nose in its work by occasional 
cleansing and sponging. 
In the close streets and lanes of cities, on dusty roads, 
and in houses, shops, or assembly-rooms, we find the 
chief pollutions of the natural atmosphere. So great is 
the evil to cities from smoke, that in some of the manu- 
facturing cities of Great Britain great effort is made to 
rid them of this nuisance by smoke-consuming and 
smoke-filtering apparatus. 
As to our usual dwellings, school-houses, or other 
assembly-rooms, the first question that naturally arises 
is, how shall we know that the air is becoming or has 
become fouled to a degree inconsistent with healthful 
indwelling? Now that it is pretty well settled what 
amount of air-space and of pure air is needed for healthy 
breathing, where we find numbers of persons shut up 
in a room not answering to these conditions, and the 
additional sources of contamination afforded by lights, 
fires, etc., we may be quite sure that the air is being 
unduly deteriorated. The next practical test is, how the 
air seems to one coming in thereto out of the open air. 
To such, there is a sensation of stuffiness or closeness The Lungs as Related to Health. 
171 
not so readily perceived by those in the room, which is 
quite an unmistakable indication. 
As the condition of the air as related to health has 
already been considered, and as under Heating and 
Ventilation it will also be discussed, we need not en- 
large upon it here. 
17. The Voice and its Health. — The human voice is 
so much a part of expression, of emotion, and can be 
educated so much like one of the senses, that it would 
not be surprising if eventually it should be classified as 
a special sense. Its apparatus is as wonderful as that 
of the eye or the ear. While utterance is a more com- 
plex process, there is a voice as well as ear and eye 
attent, and will and culture show its marvellous capa- 
cities. The larynx, or that part of the trachea or wind- 
pipe which contains the vocal cords, is the essential 
organ. While the lungs form the bellows, the pharynx, 
mouth, and nasal cavities aid in the resonance. 
The larynx, in its upper part, is a cylindrical box of 
a triangular form, growing narrow and cylindrical be- 
low. It is formed by nine cartilages, connected by liga- 
ments and moved by nine muscles, of which eight are 
in pairs. The thyroid cartilage is the largest and most 
prominent, as it unites in front at a projecting angle, 
and forms the bulge in the trachea generally known as 
Adam’s apple. The tradition is that it was so called 
because of a vagrant fancy of the Orientals that it re- 
sulted from eating the forbidden fruit. 
18. The epiglottis is the cartilage behind the root of the 
tongue, placed above the glottis so as to leave freedom 
for respiration. While the larynx is elevated in swallow- 
ing, the epiglottis falls over the glottis and closes it, and 172 
Hygiene. 
at the same time acts as a lid to cover the glottis when- 
ever the oesophagus, or tube to the stomach, is being 
used. While not a direct part of the machinery of the 
voice, it affects the vibratory motion of the air, and 
probably contributes to the timbre. 
The hyoid bone, to which the larynx is suspended, 
ascends and descends with it, and is in control of liga- 
ments and muscles. As we look into the interior of 
this wonderful music-box, we find it a movable labyrinth, 
with two folds of membrane stretched horizontally across 
it, known as the true or inferior vocal cords. Besides 
these, there are two other folds parallel to and above 
them, termed the sirperior or false vocal cords, which 
are not known to contribute directly to the formation 
of the sounds, but which aid in the adjustments. 
19. The muscles are so arranged as to give to the car- 
tilage great variety of movement, and great variation in 
the shape of the larynx and the tension of the vocal cords. 
The larynx has an abundant supply of minute vessels 
and nerves, and some small glands which lubricate the 
epiglottis and the part above the cords. The pharynx, 
or part of the throat on either side of the uvula, or palate, 
the pillars of membrane on either side, forming an arch, 
the tonsils, the nasal fossa, the cheeks, the mouth, the 
lips, the tongue, each and all have varying parts to 
perform. 
20. The mode in which the voice organ acts lias been 
variously compared to that of the violin, the flute and 
reed and pipe instruments. In some respects it com- 
bines them all. The sound results from vibrations of 
the vocal cords and ligaments, the same as occurs in 
reed instruments from elasticity of the reed and the The Lungs ms Related to Health. 
173 
varying length of the tube. The pitch depends on the 
tension of the vocal cords by which the size of the 
glottis, or inner larynx, varies, and on the ascent and 
descent of the larynx, by which the vocal tube short- 
ens and lengthens. 
In the effort to produce sound the true vocal cords 
draw nearer to each other, and the air, passing through, 
sets the vocal ligaments in vibration. Such flexibility 
in every part and such variety of air, force, tension, 
and vibration, are secured as to give an almost un- 
limited variety of tone, pitch, and intensity. There is 
a wonderful range in the adjustment of the vocal 
cords, which is so increased by practice that a singer 
has been known to have a control that could determine 
the contraction of the vocal ligaments to one-fifteen- 
thousandth of an inch. 
The quality and compass of voice which have been 
acquired is as wonderful as any of the attainments of 
the senses. We once stood near the outer door of the 
immense hall in which Mine. Parepa Rosa sang in 
New York city, and in the midst of the anvil chorus 
of hundreds of singers and all varieties of instruments, 
could distinctly catch her warbling notes, clear and 
shrill beyond and above the rest. The voice of women, 
although different from that of men, has no variation 
in its inner apparatus, except that the larynx is about 
one-third smaller. The tissue is thinner and more elas- 
tic, and so gives a more acute pitch. 
21. There is no portion of the body that admits of more 
cultivation than the apparatus which produces voice, 
and none that oftener suffers from imperfect develop- 
ment or care. The hygiene of the voice often has to 174 
Hygiene. 
do both with health and wTith success in life. Articula- 
tion and reading are among the most important early 
educational exercises. Early training in singing has 
the additional advantage that it educates the ear and 
voice together, and so gives taste and power of ex- 
pression. 
The child should be practised on notes that it can 
produce without much effort, and the exercises should 
not continue for more than fifteen or twenty minutes. 
The least vocal fatigue should be avoided. 
22. The modification of timbre and pitch of voice, 
which takes place in growing girls and boys, causing, for 
a time, a hoarse or shrill voice, is to be so far recognized 
that the voice shall not, at this period, be over-exer- 
cised or over-trained. The larynx does not acquire 
its full development before the age of twenty years, 
and may be so affected that any over use may lead to 
serious impairment. 
The skilled teacher always has careful regard to any 
changes or embarrassment that the voice has at any 
time, and will see to it that no unwise attempt is made to 
recover its timbre or compass. The highest and lowest 
notes are especially to be avoided by many. The abuse 
of the acute sounds injures many voices. Independent 
of vocal exercises, which, if properly conducted, are usu- 
ally of advantage, the voice is not infrequently injured 
by loud calling or screaming. 
23. It is always unfortunate to have to use the voice 
in speaking, singing, or much talking, when the throat 
is irritated, or when there is huskiness or hoarseness. 
Chronic laryngitis is often produced in this way, which 
sometimes becomes permanent, and is always slow of The Lungs as Related to Health. 
175 
recovery. Entire rest, the breathing of moist, warm air, 
and the use of some emollient to soften the parts and 
make up for the lack of secretion, are always the part 
of prudence. The use of the voice has such relation to 
mental exercises that all that relates to its preservation 
and quality must be guarded with judicious care. Even 
the temper can be restrained by the measured and 
low-toned voice. 
24. Eight habits of breathing, care of the breath, the 
mouth, the teeth, and of all the throat, and of the nose, 
have much to do with the perfection of the voice. Dr. 
Durant well says: “The purity of the voice results from 
the ease with which the air is expelled from the lungs; 
the precision with which the varying tensions of the vocal 
cords are made; the absence of all obstacles to the pas- 
sage of the air through-the bronchi, larynx, mouth, and 
nasal fossae; the condition of the membranes lining the 
vocal apparatus; the art with which the sonorous wave is 
modified in the buccal and nasal cavities before reaching 
the external air; and, finally, the absence of all causes 
which might oppose the action of the expiratory and 
inspiratory muscles, as well as those which move the 
larynx itself.” 
25. What has already been said as to the preserva- 
tion of the natural contour of the chest, as well as of 
the care of the breathing and digestive organs, is thus 
emphasized. There must be free action of the entire 
respiratory apparatus as well as of the muscles adja- 
cent to and below it. Unnatural modes of breathing 
are not infrequently acquired, and must be corrected 
by a return to right practice. The ribs, the dia- 
phragm, and the ventral walls have each a natural part 176 
Hygiene. 
which they instinctively perform, unless hindered hy 
dress or by ill-acquired habits. Singing involves fuller 
and more rapid respiration than is usual. The scope 
is from 6 to 30 respirations a minute, the average being 
from 16 to 18. Thus the usual respiration of about 
500 or 600 cubic inches of air per minute may be in- 
creased to 800 or 900 per minute. 
Nature has provided for this by its residual and tidal 
air, and its vastness of vesicular lung-compass, hut there 
must be culture and adaptation. What is true of sing- 
ing is measurably true of other exercises of the voice, 
as reading, elocution, talking, and shouting. All need 
training by natural methods. 
26. The proper use of the wonderful organ of speech 
is for general as well as local health. On the other 
hand, over-strain, irritation, exposure of the inner throat 
to severe cold, to heavy air, to sudden chilling by ices, 
to over stimulation with troches, is often the irritating 
cause of both local and general disturbance of health. 
Even children in school know something of the nervous 
tension and exhaustion of recitation and of vocal action. 
Foul air, too, often adds to the injury. Although talking 
and singing and speaking do not impress us as labor so 
much as do other exercises, yet rapid and exhausting 
work is being done in the larynx amid the air-cells of 
the lungs and the minute vessels of the capillary circu- 
lation. There must be good food, good sleep, and that 
1 i abit of quiet breathing and free chest expansion which 
are in contrast with nervous inhalation or breath-catch- 
ing, which betokens exhaustion or an ill habit of 
breathing. While the loss of voice is rare, its impair- 
ment is frequent. The Lungs as Related to Health. 
177 
27. It is to be remembered that for very many the voice, 
whether in the well-modulated tones of conversation or 
in the rhythm of music and song, is a chief possession 
and accomplishment, and as such is to have all that 
hygienic care which is essential, not only to its quality, 
but to the vigor of the marvellous and vital organs 
with which it is associated. A physician of London 
has acquired a world-wide reputation for his minute 
care of the throats of singers. The treatment is far 
more hygienic than medicinal, consisting in the most 
rigid attention to food, sleep, diet, care of teeth, mouth, 
throat, nasal fossa, the larynx, the chest, the lungs, the 
body as a whole. The voice itself thus becomes all the 
more admirable because it is the expression of perfect 
health of body and of mind, of soul and emotion, of 
all that constitute true life, and so gives utterance to a 
harmony of the whole nature. Chapter XI. 
DIGESTION: ITS ORGANS AND METHODS. 
THE next demand made upon the outer world for 
the sustenance of human life is for food. Just as 
the air is needed to go down to the lungs, and there 
re-vitalize the blood and remove the used-up material; 
so there is an arrangement by which food goes into 
another part of the system, has extracted from it what 
is necessary for the support of life, and then receives 
in its course much spent material for rejection. In the 
one case as in the other, the transforming and support- 
ing material enters into the blood through a minute 
system of small vessels. 
It will be necessary, in a brief way, to outline the 
apparatus through which the preparation and transfer 
of this food is accomplished. 
The following diagram gives a view of various organs, 
so that the relative position of the digestive apparatus 
may be seen. 
2. The receptacle into which the food is received is 
known as the alimentary canal. Commencing at the 
lips and mouth, and continued into the pharynx and 
back part of the mouth, it soon becomes that part of 
the tube known as the oesophagus, gullet, or food- 
pipe. This is a flexible tube behind the windpipe, and 
about nine inches in length. It then expands into a 
pouch known as the stomach, which, after being con- 
178 Digestion-. Its Organs and Methods. 
179 
tracted at its lower orifice, is continued into a tube 
known as the small intestine. This, again, expands into 
the large intestine. The stomach of a full-grown man 
is, when full, about twelve inches in length and four 
inches in its greatest diameter, and has a capacity of 
about one quart, The entire length of the intestines 
•The Lungs. 
The Lungs. 
The Heart. 
Le Diaphragm. 
The Liver. 
The Stomach. 
The Gall Bladder. 
The Large Intestine. 
■ The Small Intestine. 
PIG. XXI.— The Relative Position of the Chief Organs in the 
Chest and. the Abdomen. 
is about twenty-six feet, of which the large intestine 
constitutes six feet. This flexible pipe is arranged in 
folds, and has connected with it various glands and 
tubes which perform a part in the digestive act. 180 
Hygiene. 
The following figure shows the course of the food, 
with some of the accessory organs, as far down as the 
upper part of the pelvis. 
Salivary Glands 
Pharynx 
Salivary Glands. 
(Esophagus. 
Left Subclavian Vein. 
Liver turned upward, 
Thoracic Duct. 
Gall Bladder and Bile 
Duct. 
Stomach turned upward 
Pyloric End of Stomach. 
Spleen 
Small Intestine. 
Panereas. 
Large Intestine, J 
or Colon. 
Laeteals, or Chyle Lym- 
phatics. 
Descending portion of 
Colon. 
Union of Small and Large 
Intes. at Ileo-ccecal Valve- 
Convolutions of Small , 
Intestines. | 
FIG. XXII.—Showing- the Digestive Apparatus, and the Course 
of the Food. 
3. The mouth is the irregular cavity which forms the 
beginning of the alimentary canal, and which is in- 
tended for the mastication and mingling of the more 
solid food. It is lined by mucous membrane. It con- 
tains the tongue, which, by its muscular arrangement 
and shape, is well-fitted to aid in the movement of the 
food. Both the mouth and the tongue have their lining 
or mucous membrane studded with buccal glands about Digestion: Its Organs and Methods. 
181 
the size of millet-seeds, which, through their ducts, pour 
out saliva, and so add to the moisture of the food. Most 
of the saliva is supplied by the two glands under the 
tongue known as the sub-lingual, two under the jaws 
known as sub-maxillary, and two just at the bend of 
the jaw and below the ears known as the parotid glands. 
The ducts of the parotid glands open nearly opposite each 
second, upper, molar tooth; those of the sub-maxillary 
glands, under the tongue at its junction with the under 
surface of the mouth; and the sub-lingual glands, quite 
near to these. These fountains of saliva, or spittle, are 
furnished not only to moisten the mouth and the food 
and render it fit for mastication, but these juices help 
to make the starchy matter of foods soluble by aiding 
in its conversion into sugar. Starchy foods cannot be- 
come nutritive until this change is wrought in them. 
It is because of the absence or scarcity of those juices 
which especially affect starch, in young and unweaned 
children, that starchy foods are not so good for them. 
The combined juices of the mouth are slightly alka- 
line. From one to three pounds, or, on an average, over 
a quart per day, is secreted by an adult. The amount 
varies much according to the amount and dryness of 
the food and the degree of mastication. 
4. Here is manifest the importance of deliberate 
and thorough mastication. Eating should be one of 
the most deliberate and thorough of all the duties of 
life. A minute division of the food in the mouth, and 
its mixture there with air and with saliva, are the first 
essentials to good digestion. The rest of the digestive 
track, if called upon to make up for defects in the first 
process, will eventually show the ill-effects. 182 
Hygiene. 
Besides this process of mixing, the mouth has been 
fitted for the thorough grinding and crunching of food. 
The muscles that operate the lower jaw are so arranged 
that great force can be exerted, and with such change 
of direction as shall give advantage for thorough division. 
Biting, grinding, crushing, moistening, besides the mix- 
ing with air and digestive juice, are all to be accom- 
plished in the mouth. Neglect of any of these is the 
beginning of wrong-doing to the whole digestive appa- 
ratus. 
The entire arrangement of the teeth is admirably 
adapted for their purpose. In order that there may be 
FIG- XXIII.—The Teeth, showing temporary set of the upper 
jaw and the 6th year Molars of second set. 
no failure, a reserve set is furnished to take the place 
of the twenty of the temporary set which answers for 
earlier life. 
5. The permanent teeth, thirty-two in number, are ar- 
ranged in the form of arches in the upper and lower 
jaws. The sixteen teeth of each jaw have four types or Digestion.- Its Organs and Methods. 
183 
shapes, and are therefore known as the four incisors, or 
cutting teeth; the two canine, or tearing teeth, the four 
bicuspid or double-pointed crowns, both for cutting 
and crushing, and the six molars or grinders. These 
again are so varied in their surfaces as to give every 
advantage for the reduction of food. 
6. What are known as the sixth-year molars deserve a 
special notice, because they are so frequently confounded 
with the first set of teeth. The reason of this is that 
these back teeth of the upper and lower jaw on either 
side make their appearance before any of the first teeth 
are shed. But if neglected, as they too often are, they 
are early lost or never replaced. When you are able to 
count a row of eleven or twelve in each jaw, you may 
be sure that the last molar on either side belongs to the 
second set. Teeth, like bones, are not fully solidified in 
early childhood, and even the second set needs to be 
allowed to acquire hardness, instead of being converted 
into nut-crackers. It is a good plan to have a dentist 
look at these first permanent teeth as soon as they are 
fairly through, so that any possible tendency to decay 
may be checked. These sixth-year molars have been 
given writh the plate of the temporary teeth in order to 
attract attention to them. 
7. The following table gives the order of the full 
upper set of teeth, which have their sixteen opposites 
in the lower jaw. 
The permanent set appears about as follows: 
First molars 5 to 6 years. 
Central incisors 6 to 8 “ 
Lateral incisors 7 to 9 “ 
First bicuspids 9 to 10 “ 184 
Hygiene. 
Second bicuspids 10 to 11 years. 
Canines 11 to 13 “ 
Second molars 12 to 14 “ 
Third molars, or wisdom teeth . . 17 to 22 “ 
8. In good constitutions, when well taken care of, and 
when used as they should be for mastication, the perma- 
nent teeth last a lifetime. But if not cared for as they 
should be, the membrane of the mouth becomes affected 
by the condition of the stomach, the gases of imper- 
fect digestion come up and act upon the teeth, and 
there is premature loss. In cases of perfect digestion 
and of inheritance of good teeth, we find that they 
are generally kept until old age, without the necessity 
of any special care. 
But conditions, as we have them, are so artificial that 
there is, as a rule, need of careful attention to the teeth. 
Rinsing of the mouth after each meal, and on rising 
and going to bed, are most important. The brushing 
of the teeth, so as to remove any particles of food, is 
also a valuable aid. Slight decay of the teeth, and 
closeness or irregularity, not only do harm directly, 
but indirectly, by the retention of small particles of 
food that hasten to decay, and so cause bad breath 
and foul air. 
When there is a tendency for tartar to collect 
about the teeth, care must be taken that not merely 
the points of the teeth are brushed, but that they are 
touched by the brush all along the gums. Decaying 
teeth should either he filled or removed. In order 
to preserve the contour of the jaw, it is not deemed wise 
to pull many of the first teeth, but they can be cheaply 
filled with temporary filling. Digestion: Its Organs and Methods. 
185 
9. The care of the teeth and the chewing of the food are 
so much within the reach of personal habits, and are so 
essential to good digestion, that not onty should children 
be advised, but they should be trained into methods of 
care. 
Brushes are of much value, but are intended for rub- 
bing rather than scrubbing the teeth. There is no need 
of elaborate powders. Precipitated chalk or orris-root 
powder answers the purpose. Thorough attention to 
the mouth, in order to keep its membranes and the 
dental arches in the best condition, secures not only a 
sweet breath, but good health. Any oversight here is 
a neglect of that part of the digestive apparatus which 
we can most easily reach. 
10. The food having had proper reception in the 
mouth, and having been thoroughly mingled with its 
juices, and masticated by its dental apparatus, is now by 
a peculiar muscular and peristaltic action carried to 
the funnel-shaped opening behind the mouth, known 
as the pharynx, and so on to the gullet, or oesophagus, 
which ends in the upper and left side of the stomach. 
It there comes to an organ having wonderful arrange- 
ments for movement, and a juice is freely poured 
into it from various glands, follicles, and ducts in the 
walls. A healthy stomach can, if need be, furnish 
three gallons of digestive juice each day. 
The thin, acid fluid thus furnished is known as the 
gastric juice. The proteids or albuminoids of the food, as 
they are called, are dissolved and absorbed directly by 
the veins of the stomach, which are arranged with thin 
walls so as to admit of this absorption. The water 
is also freely taken up. So much of the starch of the 186 
Hygiene. 
food as has been well mingled with the saliva, so as to 
be converted into sugar, is also disposed of here. 
11. The flow of this gastric juice is greatly influenced 
by mental and nervous states, by exercise, by kinds of 
food, by appetite, etc. Great anxiety or excitement will 
partly suspend the action of the stomach. As water- 
ing of the mouth takes place over food, so with a 
strong desire for food there is an increase of digestive 
juices. Fatigue, or over distension of stomach, inter- 
feres with the flow, while exercise and a sensible meal 
increases it. Condiments and stimulants momentarily 
increase it, but when continuously used they tend to 
corrugate the folds of the stomach and to enfeeble its 
secretive functions. Thus many stomachs are greatly 
injured by alcohol and by sharp condiments. 
We can learn a great deal as to what solid and liquid 
foods to use by studying how they are dealt with in the 
digestive canal. The muscles of the stomach are so 
arranged as by their contraction and relaxation to 
agitate the food, and by a partial onward movement to 
push it out into the next part of the digestive canal. 
12. The stomach is of an elongated shape, and has such 
a poucli-form as to be pressed out when full. Some- 
times palpitation of the heart results from its over- 
distension. The point where the foods enters it is 
called the cardiac end. The lower end is the pylorus, 
so called because it is closed like a gate, admitting 
and retaining the cruder portions until, at the close 
of the digestive process, or its partial suspension, it 
relaxes aud lets through the denser material. 
While the stomach is so important an organ of diges- 
tion, it is to be remembered that it deals with only a Digestion: Its Organs and Methods. 
187 
part of our foods. It does not act on fats or starches, 
but stops the action of other juices upon them. 
The pepsin and hydrochloric or lactic acid of the 
gastric juice acts as a solvent on the proteids or albu- 
minoids to be hereafter described. 
These are so acted on that a great deal of the fluid 
which results from stomach digestion is at once ab- 
sorbed through the delicate meshes of the multitude of 
minute vessels of the stomach into the blood current 
which the gastric veins gather into the portal vein, 
which carries it to the liver. 
13. All the rest, in the form of an acid gruel called 
chyme, is passed into the next portion of the digestive 
track. This mixture is somewhat varied by the food, 
but consists chiefly of the amyloids, or starchy foods, 
not yet converted into sugar, and the albuminoids, 
which have not been absorbed, together with a little 
sugar, saliva, and gastric juice, and the indigestible 
parts of the food. The digestive tube which receives 
the chyme is about twenty feet in length, and is called 
the small intestine. Its parts are generally spoken of 
as the duodenum, the jejunum, and the ileum. 
So soon as the chyme has passed the pyloric or lower 
orifice of the stomach, it meets the three fluids known 
as the biliary, the pancreatic, and the intestinal, and the 
name is changed to chyle. The biliary or hepatic juices 
come to it by a small duct, which is the united duct 
from the liver and the gall-bladder. It enters about 
three inches below the pylorus. It empties into the 
digestive stream from two to three pounds of fluid 
each day. This fluid has a twofold character. It is 
the used-up material which has been separated from 188 
Hygiene. 
the blood in the liver, and therefore is of the nature 
of an excretion or excrement; it also contains materials 
for neutralizing the acid of the gastric juice, and for 
converting fats into an emulsion. It is called bile. 
The substance called glycogen is made in the liver 
from the digested materials brought to it by the portal 
vein. It tends to change into glucose-sugar in the 
presence of an animal ferment. This is a part of the 
digestive process, and furnishes respiratory fuel or food. 
14. The pancreas, or “sweet-bread,” is a small gland 
close to the stomach, and has a duct at its terminus 
which enters the intestine so near the bile-duct as to 
seem to form a common duct. The entrance is not 
far from the middle of the bend of the duodenal 
portion of the small intestine. The pancreas secrete 
about one-half pint of juice a day. It acts on starchy 
substances and on the albuminoids or proteids, and 
aids the digestion of fats. Besides these fluids from 
glands or organs, the mucous membrane of the intestine 
is provided with numerous small and mostly simple 
glands which pour into it a secretion of less defined 
function, which is spoken of as the intestinal juice. 
All these liquids unite to extract and appropriate from 
the chyle or chyme the nutrition it is capable of im- 
parting. The digestion of albuminous matter is com- 
pleted, the fats are emulsionized so as to be appro- 
priated by the system, and the starches fully converted 
into sugars. 
15. These constituents of food, thus acted upon and 
prepared, are absorbed by the veins and by small tubes 
known as lacteals. Those taken up by the veins of the 
intestines follow the same course as those taken up by DigestionIts Organs and Methods. 
189 
the veins of the stomach, and enter the portal or liver 
circulation first. The other portion consisting mostly of 
emulsified fats, passes into the lacteals, and is gathered 
into a special tube known as the thoracic duct, and 
so passes into the left subclavian vein, and to the 
heart, and becomes a part of the blood, as before noted. 
16. “The lower part of the thoracic duct is dilated, 
and is termed the receptacle or cistern of the chyle. It 
receives the lymphatics of the intestines, which, though 
they differ in no essential respect from other lymphatics, 
are called lacteals, because they are filled with a milky 
fluid, which is termed the chyle. The lacteals or lym- 
phatics of the small intestine not only form networks 
in its walls, but send blind prolongations into the little 
velvety processes termed villi, with which the mucous 
membranes of the intestines is beset. The trunks which 
open into the network lie in the mesentery or mem- 
brane which suspends the small intestine to the back 
wall of the abdomen. The glands through which these 
trunks lead are hence called mesentric glands.” 
17. The movement of the fluid along the intestines is 
accomplished by the progressive and worm-like action 
of the muscular coat of the intestines, which is called 
peristaltic action. The alkali of the bile neutralizes the 
acid, and the bile and pancreatic juice emulsionize 
or sub-divide the fats into very small particles, which 
are held in the fluid much as cream is suspended in 
milk. When the chyme-acid is neutralized, the conver- 
sion of starch into sugar, which is mostly suspended in 
the stomach, takes place rapidly under the action of the 
biliary, pancreatic, and intestinal juices. 
The fluid is called chyme as it passes from the 190 
Hygiene. 
stomach, but as it thus becomes acted on is called chyle. 
It is moved along by the contractile action of the 
small intestines, and the dissolved matter is absorbed 
by the vessels of the villi, as before described. The 
minute particles of fatty matter, by a little different 
squeezing process, find their way into the vessels. So 
between the blood-vessels and the lacteals the nutrients 
contained in the food are appropriated. The semi-liquid 
material, thus deprived of the peptone, or digested albu- 
minous matter; of the soluble amyloids, or starchy mate- 
rials converted into sugar; and of the sugars and fats, 
passes through a fold of the intestine, which forms a 
valve known as the ileo-csecal valve, which marks the 
change from the small to the large intestine. Here 
there is, in the upper part of this intestine, an acid 
reaction, and probably some remaining portions of the 
food are appropriated. Then the portion not appro- 
priated as food, and the excrementitious secretions, pass 
on to their separation from the body. 
18, While it is not necessary to present all the minute 
details of the digestive process, this much is needful to 
be known, in order that we may speak intelligibly of 
the hygiene of the digestive track. First of all, none 
of the organs concerned in digestion need, or admit of, 
artificial pressure. The stomach is intended for expan- 
sion, and where food is taken the extension of its 
surface is a part of the method by which the flow of 
gastric juice is increased, while its rolling and slightly 
peristaltic motion is a mode of mingling and digesting 
the food. 
Cords or bands, or stays of any kind, pressing too 
hard upon it, interfere with its size and movement. Digestion: Its Organs and Methods. 
191 
Physicians distinctly recognize forms of dyspepsia in 
which there is either constriction, or irritable distention 
of the stomach and muscular spasm, or other interfer- 
ence with its normal motions. Pressure upon it also 
causes it to press unduly upon adjacent organs, and so 
may irritate and disturb them. 
The diaphragm, which is the movable muscular parti- 
tion between the thorax and the abdomen, and has 
much to do with breathing, often suffers from undue 
pressure. Hiccough is often the sign that it is pressed 
upon by some distended organ, or that some form of 
nervous irritability is conveyed to it. 
The heart is not infrequently affected by such press- 
ure, and also by the over-distention of the stomach by 
food, liquids, or gas. 
The liver is so large an organ, and has so much to 
do in the digestive process, that it, too, may suffer 
from undue compression. It is the largest gland in the 
body, weighing about four pounds, and sending into 
the intestine each day an amount of fluid one-half of 
its own weight, which passes into the upper intestine 
just below the stomach. It is located where undue 
pressure about the waist has a tendency to press or 
displace it. 
19. But the great injury that comes to the digestive 
apparatus is from taking into it materials either too 
frequently or not frequently enough, or not containing 
the right quantity of food rightly prepared. Frequency 
of eating should be regulated by age, or by the demands 
made upon the system. Growth is of itself a demand. 
In the growing period, digestion and circulation, waste 
and repair, are more rapid than at full age. Parkes 192 
Hygiene. 
says, that in the period of growth the utmost limits 
between the meals should be four hours. The heartier 
meals should be in the morning, and not later than 
six o’clock in the afternoon; but no one should go to 
bed hungry. 
In the selection of food, we are guided much by ap- 
petite. But as appetite may be artificial, we also need 
to find out what are the foods which study and expe- 
rience have shown to be essential. By the aid of chem- 
istry, and of inquiries into the physiology of digestion, 
great progress has been made in the last twenty-five 
years in the knowledge of foods, such as has greatly 
added to their variety and adaptation, and such as 
ought to aid much in the promotion of health. 
It is easily shown that the stomach of man is only 
intended for such food as is liquid or semi-liquid, 
or such as has been reduced by mastication. It must 
contain in it those ingredients which it is known the 
system will demand from it, or such as it has the power 
by its own additions and changes of converting into 
nutritive material. We easily find that constant de- 
pendence upon liquid foods is not desirable, except in 
certain enfeebled conditions of the stomach. 
The temperature at which digestion goes on is from 
98° to 100° F. If this is reduced by cold food or ice- 
water, so as to interfere with quick reaction, digestion 
does not begin, or is interrupted. When the stomach 
is in any way enfeebled in digestion, some warm drink 
just before or with a meal is often found of service. 
The kinds of food, and the preparation of foods as to 
cooking, will be considered elsewhere. 
20. The quantity of food depends on the demands Digestion-. Its Organs and Methods. 
193 
of the system, and is therefore variable. Because there 
is an approximate law, we generally eat three times per 
day. But there may be days when four meals are 
needed, just as much as three or two are needed on 
other days. Food and sleep are relative to each other, 
so that persons who sleep well and long do not need so 
much food as those who spend less time at rest. 
The taking of a large amount of indigestible material 
with the food tends to disturb the process of digestion. 
Nature has provided for the disposal of certain parts of 
foods which are not convertible into blood or tissue, but 
not to such an extent as to warrant the use of articles 
having in them no food material. Cast-off matter con- 
sists not so much of that which has not been digested 
as of that which is separated from the system in the 
process of waste and repair. 
21. It is easy to see how the membrane of the intesti- 
nal track can be injured by putting into it substances 
which interfere with its natural processes. If we take 
very hot condiments into the mouth we are conscious 
that they act unnaturally and unfavorably upon its 
membrane. If they burn it so that we have to cool 
it, we find that a condition has resulted which requires 
a reparative or healing process. If we keep on putting 
the same material in the mouth until it becomes used 
to it, what we call toleration is established. This 
does not prove that in this continued use, without the 
discomfort had in the first instance, we are doing no 
harm. While the harm is not so declarative, and 
while it may be modified by the adjusting powers of the 
human system, inquiry into the effect upon internal 
organs and their functions leaves no doubt that vital 
force is impaired. 194 
Hygiene. 
The digestive track thus comes to endure cayenne- 
pepper, tobacco, alcohol, and various other substances, 
which, when first taken, are irritative to the mem- 
branes, and which are not needed. No one can study 
the minute anatomy and physiology of the wonderful 
apparatus of digestion, and see the effect which im- 
proper foods and drinks have upon its delicate struc- 
ture, without realizing that we must give to the system, 
and to each physiological process of it, such material as 
it was intended to operate upon. If it is found that 
any fluid placed on the mucous membrane of the stom- 
ach engorges its minute blood-vessels beyond the usual 
fullness for the digestive process, and constricts the 
various follicles and minute gland-ducts of the stomach, 
so that they can no longer pour forth, in their natural 
method, the juices needed for digestion, the proof is 
positive that there is interference with good digestion. 
This has been frequently enough proved as to certain 
sharp-tasting substances, .and so-called condiments, and 
as to alcohol. In addition to this it has been shown 
that so-called moderate drinkers eventually have im- 
pairment of the vital acts of digestion, and that the 
stomach, the liver, the intestines, and the kidneys reg- 
ister effects which are prejudicial to health and long 
life. 
22. The effect of materials taken into the stomach is 
sometimes to be inferred from the immediate results; 
sometimes from the results secured by a systematic 
plan for a long time in which, by increase of appetite, 
or of weight, or by improved health, or the opposite of 
these, we are able to prove the influence of the article 
used. Frequently where there is apparent advantage Digestion : Its Organs and Methods. 
195 
for a time, we are able to show by the impairments of 
organs or functions, or by an early decay of vital 
powers, that what seemed of temporary advantage, or 
at least tolerable, has proven to be injurious. 
While the appetites and preferences and prejudices 
of men, or their insufficient facts and inconclusive rea- 
sonings often lead to error, yet it is encouraging to 
know that there are many careful and candid and 
competent observers who collect evidence and give it 
logical consideration, and so secure for us reliable results. 
When we come to consider Foods, it will be apparent 
that nature has made an adaptation between the diges- 
tive organs and food materials which should guide us 
in the choice of foods and the methods of their prepa- 
ration. Chapter XII. 
OUR FOODS AND THEIR USES. 
IN the study of the human system, for an inquiry 
into the best methods of keeping it in health, we 
necessarily have occasion to find out whence it ob- 
tains the material which it is able to change into 
vital force. We have found that its nutrition is chiefly 
derived from the blood, and that this obtains its supply 
from materials furnished in foods and drinks that are 
conveyed to it through the digestive apparatus. 
As we ascertain the various constituents of which 
the body is composed, and by which it exerts its force, 
we inquire whether these are furnished in the foods 
and drinks used, or whether there is a chemistry of 
digestion which converts these into food. We could 
not be at all sure as to our views without some 
examination of the foods and drinks which enter into 
the system. If we find in these the very substances 
which are found in the human system, and which we 
there find convertible into life-force, and are able to 
trace the modes of appropriation, we are enabled to 
recognize their true value as foods. 
The inquiry is the more important because it enables 
us, in a large degree, to estimate the value of foods 
and drinks, and so to determine the indications for 
their use. As the value of the food also depends on its 
preparation, and on the way in which it can be trails- 
196 Foods and their Uses. 
197 
formed in the stomach, we will need to look briefly into 
modes of preparation as they are carried on outside of 
the body in the processes of division and in cookery, as 
also to those changes which are wrought within, and 
which, by converting one substance into another, con- 
tribute to life and health. 
2. The division which has been generally accepted, of 
materials contained in the system, is into two classes. 
First, that which furnishes the substance for the body 
itself; and next, that which furnishes the heat which 
maintains the temperature of the body. These are 
often distinguished as flesh-producing and heat-pro- 
ducing foods. The chemists term them nitrogenous 
and non-nitrogenous foods, nitrogen being a chief con- 
stituent of the flesh or body-forming foods. If we 
could accurately draw the line betwixt the two, it 
would be expressed as follows: 
I. Nitrogenous: 
Flesh-forming. 
Muscle or tissue repairing. 
II. Non-nitrogeneous, or carbonaceous: 
Fat-forming. 
Heat-producing. 
Force-giving. 
The first includes not only the material of which 
the body is made, but also that which is needed to re- 
pair the wastes of the body. The second includes the 
food which produces muscular and intellectual strength 
for work. 
The nitrogenous matters are so largely represented 
by albumen, of which the white of eggs is an example, 198 
Hygiene. 
that these are sometimes called the albuminoids. They 
are also called protein compounds (Gr. npdnoc, first), 
and are the flesh-forming and muscle and tissue repair- 
ing foods. These exist largely in meat, and in some 
vegetables, as beans. 
Eats, and also sugar and starch, belong to the oppo- 
site, or carbonaceous class. The latter are sometimes 
called carbohydrates, and are very important, They are 
convertible into heat and force, and reappear but little 
in the organic body. 
3. The chief examples of each of these divisions of 
food may be stated thus: 
Albumen, as in eggs, beans, etc. 
Gluten, as in wheat and other cereals. 
Casein, as in milk, cheese, etc. 
Fibrin, as in meat, fish, etc. 
Gelatine, as in jellies, etc. 
I. 
All fats or oils. 
Starch, as in potatoes, rice, grains, etc. 
Sugars, as in fruits, sugar-cane, and glucose. 
II. 
These two classes of foods, with water as the great 
conveyancer or medium of exchange, and with a few 
alkaline or other salts, are indispensable as material 
for the body and for the exercise of force. 
4. The salts are chiefly the phosphate of lime, which 
forms the basis of the bones, and phosphates, sulphates; 
and chlorides of potassium and sodium, with a little 
magnesium and iron. Common salt, or chloride of 
sodium, is the only one which, as a rule, has to be sup- 
plied in addition to the ordinary foods, and chiefly 
as an aid in digestion and assimilation. These, for Foods and their Uses. 
199 
distinction, are called mineral compounds, while the 
others are called organic compounds. Yet, as we have 
seen, the organic compounds are generally the media 
or conveyancers of these mineral compounds. 
It is not incidental that the organic compounds 
of our bodies and our foods are found to be the same, 
for the latter become foods by virtue of the demands of 
our bodies. In an average man, weighing about 150 
pounds, chemists have reckoned the water to be about 
90 pounds; the nitrogenous matters or albuminoids, 
27h pounds; the fats, 23! pounds; the mineral matters, 
8! pounds, and the carbohydrates, etc., a trace. 
Milk, as containing all these aliments in their readiest 
form, is a representative food. 
5. The distinction between the flesh-forming and the 
heat-producing foods cannot be perfectly drawn, since 
under some circumstances the one is convertible into 
the other. Most foods contain some proportion of each. 
As a rule, those foods which contain each about in 
the proportion required by the system in the state 
of health, practically are found to be the foods in 
most universal use. In digestion, the starches are con- 
verted into sugars, and thus aid considerably in pro- 
ducing animal heat and fat. The heat-producing power 
of fat in its natural state is about twice as great as 
that of starch or sugar. An attempt to reckon the 
value of foods precisely from the proportion of their 
constituents fails, because neither class of foods is en- 
tirely exhausted of its energy or power in digestion, 
and because the conditions of the system and various 
self-contained powers of the temporary supply modify 
the close relation between the constituents of foods 200 
Hygiene. 
and of the body. Those, however, who have studied 
these subjects, have not confined themselves to theo- 
retical considerations, but with these in view, and with 
comparison made by the actual weighing and assort- 
ment of foods, have been able to deduce many valuable 
guides as to their effective and economical use. 
The daily requirements of the body may thus be 
stated : 
Stated . Nitrogenous, or Carbonaceous, or 
Flesh-producing Food. Heat-producing Food. 
During idleness 2.73 ounces. 20.60 ounces. 
During routine or regular work 4.48 “ 26.44 “ 
The need during illness is equivalent to a little over 
two pounds of wheat-bread, lightly buttered, and that 
during work to three and one-half pounds of bread. 
This gives, for a working-man, a need of about six 
times as much of the heat or force producing as of the 
flesh or tissue producing foods. 
Professor Huxley has thus given his conception of 
the constituent elements of a model human body, and 
of its daily demands and losses in the full exercise of 
its physiological functions : — 
A full-grown man should weigh 154 pounds, made up 
thus: muscles and their appurtenances, 68 pounds; skele- 
ton, 24 pounds; skin, 10-g- pounds; fat, 28 pounds; brain, 
3 pounds; thoracic viscera, pounds; abdominal viscera, 
11 pounds; blood which would drain from the body, 7 
pounds. This man ought to consume per diem lean beef- 
steak, 5,000 grains; bread, 6,000 grains; milk, 7,000 grains; 
potatoes, 3,000 grains; butter, 600 grains; and water, 
22,900 grains. His heart should beat 75 times a minute, 
and he should breathe 15 times a minute. In twenty-four 
hours he would vitiate 1,750 cubic feet of pure air to the Foods and their Uses. 
201 
extent of 1 per cent; a man, therefore, of the weight men- 
tioned ought to have 800 cubic feet of well-ventilated 
space. He would throw off by the skin 18 ounces of 
water, 300 grains of solid matter, and 400 grains of car- 
bonic acid every twenty-four hours, and his total loss during 
the twenty-four hours would be 6 pounds of water, and 
a little above 2 pounds of other matter. 
6. Without going into extended detail, it is very easy 
for any one to see how important are the studies of 
the food-values of different articles. We have come to 
know, very nearly, what are the requirements of the 
human system as to the material it is seeking to ob- 
tain from without. 
We are able, in many substances, to identify the pre- 
cise materials which are thus required for the body, 
and measure the amount which is stored in each kind 
of food. We are also able to determine whether they 
are in the simple form for a ready digestibility, or 
whether they are so combined as to embarrass their 
ready appropriation by the system. In many cases, 
like that of starch, while not finding the precise article 
required by the system, we find an article readily con- 
vertible into the one required, and can precisely de- 
termine the method and conditions of its conversion. 
AVe are also able to estimate circumstances in which, 
not only by excessive work, but by loss of sleep, or 
foulness of air, or special states of health, extra de- 
mands are made upon the system, which must be met 
by corresponding increase of food. 
7. We find also that many vegetables have in store the 
very foods that are contained in flesh. Although there 
is a sense in wdiich flesh is an advance in the process 202 
Hygiene. 
of digestion and a concentrated food, since the animal 
is an extract from the vegetable, yet, as in albuminous 
substances, for instance, we find some vegetables equally 
rich, and giving up their food very readily to the sys- 
tem. Thus the common haricot or kidney-bean and 
the lima-bean have a large store of such food, and are 
very valuable as a substitute for meat. Indian-corn, 
well-cooked, has much of the strength of meat, and is 
rich in oil. 
While from the composition of each food it is not 
easy to state what amount should be consumed by each 
person, and while, therefore, it is not worth our while 
here to repeat the elaborate tables which have been 
made, yet it is easy to see how, by studying these, and 
by studying both the science and the art of feeding, 
we are able to arrive at many valuable results. We 
can thus quite confidently indicate what are the best 
and most economical foods in general, and for those 
engaged in any special departments of work. 
Seeing what constituents are needed by the system to 
produce flesh, or heat and force, we note next to what 
extent these are found in some of the more valued 
foods. 
8. The fibrin, albumen, casein, gelatin, and gluten are 
the chief nitrogenous foods. 
Fibrin is found chiefly in butchers’ meat and poultry, 
19 to 22 per cent; in fish, 13 to 15 per cent. 
Albumen is found in butchers’ meat and poultry, 2 to 
3 per cent; in fish, 4 to 5 per cent; in eggs, 15 to 18 
per cent; and in ox-liver, 20 per cent. 
Casein is found chiefly in milk, the proportion for that 
of cows being 4a per cent. Foods and their Uses. 
203 
Gelatin is contained in fish and butchers’ meat, 6 to 
7 per cent; in bones, 39 to 49 per cent; in isinglass, 70 
to 93 per cent. The chemical composition of animal 
and vegetable albuminates is very similar, and they mani- 
festly serve equal purposes in the body. 
Of gluten there is in common turnips of one per- 
cent; in cabbage, of one per cent; in red beets, 14 
per cent; in potatoes, 3 to 4 per cent; in Indian-corn, 
dry peas, and rice, about 34 per cent; in barley, 6 per 
cent; in oats (Scotch), 8f per cent; in wheat (usual 
range), 11 to 15 per cent; in rye, 8 to 10 per cent; in 
beans, 104 per cent. 
Eats are supplied as follows: Lard and drippings 
contain 98 to 99 per cent; suet and fresh butter, 874 
per cent; dried bacon, 744 per cent; green bacon, 714 
per cent; fresh mutton, 45 per cent; cocoa and choco- 
late, 42 per cent; fresh beef, 334 per cent; salted beef, 12S 
per cent; cheese, 28 per cent; eggs, 11 per cent; fresh 
herrings, 7 per cent; Indian-corn, 54 per cent; oatmeal, 
5 per cent; new milk, 34 per cent; skim-milk, 2 per 
cent; buttermilk, 14 per cent; wheaten flour, 1 per cent; 
and even bread and rice, I per cent. These percentages 
will be larger if the fat be in its ordinary and not 
dried state; the difference is in the water which the 
fat ordinarily contains. 
Sugar and starch are the chief representatives of the 
carbohydrates or carbonaceous foods which are not fat, 
and are found mostly in cereal and vegetable foods. 
Of sugar we have as follows: Rice, about 1 to 2 per 
cent; maize, 14 per cent; peas, 2 per cent; rye-meal 
and wheaten bread, 34 to 34 per cent; cows’ milk, 4f 
per cent; oatmeal, 8 per cent; wheaten flour, from 6 204 
Hygiene 
to 8 per cent; beet-root, 5 to 10 per cent. Fruits vary 
from 10 to 20 per cent. Potatoes have about 2 per 
cent. 
In starches, various kinds of potatoes vary from 12 
to 24 per cent; beans, 34 to 36 per cent; wheaten bread, 
534 per cent; wheaten dour, 564 to 72 per cent; oat- 
meal, 59 per cent; rye-meal, 61 per cent; barley-meal, 
67 per cent; maize, 81 per cent; rice, 83 to 85 per cent. 
Arrow-root, sago, and tapioca contain a still larger 
proportion of starch. 
9. Remembering that the protein, albuminoids, or nitro- 
genous nutrients represent the flesh-forming and tissue- 
repairing foods, and the fats and carbohydrates the 
noil-nitrogenous, carbonaceous, or heat and force pro- 
ducing foods, as nearly as distinctions can be drawn, 
the following tables of Prof. W. O. Atwater will give an 
idea of the proportions in ordinary foods as purchased. 
They are worthy of careful notice, as an indication of 
relative values, and as showing how nearly the findings 
of experimental science correspond with our experience. 
We are also much helped in preparing dietaries, and in 
suiting foods to the varying requirements of the system. 
The table of Bell which follows, showing the constit- 
uents of cereals, also gives a correct idea of relative 
values. Foods and their Uses. 
205 
TABLE I. — Composition of Animal Poods. 
Edible Portion. — Flesh, etc., freed from Bone, Shell, and other Refuse. 
Kinds of Food-Matekials. 
(Italics indicate European analy- 
sis, the rest are American.) 
Nutrients. 
Water. 
Total Nutrient 
I Nitrogenous or 
I (albuminoids). 
j Fats. 
Carbo- 
hydrates. 
| Ash. 
MEATS. - Fresh. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Beef, side, well fattened .... 
54.6 
45.4 
17.2 
27.2 
1.0. 
Beef, lean, nearly free from fat . 
76.0 
24.0 
21.8 
0.9 
1.3 
Beef, round,* rather lean . . . 
66.7 
33.3 
23.0 
9.0 
1.3 
Beef, sirloin,* rather fat.... 
60.0 
40.0 
20.0 
19.0 
1.0 
Beef, neck,* “ second cut ”... 
64.5 
35.5 
19.9 
14.5 
1.1 
Beef, liver 
69.5 
30.5 
20.1 
5.4 
3.5 
1.5 1 
Beef, tongue 
63.5 
36.5 
17.4 
18.0 
1.1 
Beef, heart 
43.5 
16.3 
26.2 
1.0 | 
Veal, lean 
78.8 
21.2 
19.9 
0.8 
0.5 
Veal, rather fat 
72.3 
27.7 
18.9 
7.5 
1.3 
Mutton, side, well fattened . . 
45.9 
54.1 
14.7 
38.7 
0.7 
Mutton, leg 
61.8 
38.2 
18.3 
19.0 
0.9 
Mutton, shoulder 
41.4 
18.1 
22.4 
6.9 
Mutton, loin (chop) 
49.3 
50.7 
15.0 
35.0 
0.7 
MEATS. — JPrepared. 
Dried Beef 
58.6 
41.4 
30.3 
4.4 
6.7 
Corned Beef, rather lean . . . 
58.1 
41.9 
13.3 
26.6 
2.0 
Smoked Ham 
41.5 
58.5 
16.7 
39.1 
2.7 
Pork, bacon, salted 
10.0 
90.0 
3.0 
80.5 
6.5 
FOWL. 
Chicken, rather lean 
72.2 
27.8 
24.4 
2.0 
1.4 
Turkey, medium fatness .... 
66.2 
33.8 
23.8 
8.7 
1.3 
Goose, fat 
38.0 
62.0 
15.9 
45.6 
0.5 
DAIRY PRODUCTS, EGGS, Etc. 
Cow’s Milk 
87.4 
12.6 
3.4 
3.8 
4.8 
0.7 
Cow’s Milk, skimmed 
90.7 
9.3 
3.1 
0.7 
4.8 
0.7 
Cow’s Milk, buttermilk .... 
90.3 
9.7 
4.1 
0.9 
4.0 
0.7 
Coio’s Milk, whey 
93.2 
6.8 
0.9 
0.2 
5.0 
0.7 
Cheese, whole milk 
31.2 
68.8 
27.1 
35.4 
2.4 
3.9 
Cheese, skimmed milk .... 
41.3 
58.7 
38.3 
6.8 
9.0 
4.6 
Butter 
9.0 
91.0 
1.0 
87.5 
0.5 
2.0 
Hen’s Eggs 
73.1 
26.9 
13.4 
11.8 
0.7 
1.0 
FISH, Etc. 
Flounder, whole 
84.2 
15.8 
13.8 
0.7 
1.3 
Haddock, dressed 
81.4 
18 6 
17.1 
0.3 
1.2 
Bluefish, dressed 
78.5 
21.5 
19.0 
1.2 
1.3 
Cod, dressed 
82.6 
17.4 
15.8 
0.4 
1.2 
Whitehall, whole 
69.8 
30.2 
22.1 
6.5 
1.6 
Shad, whole 
70.6 
29.4 
18.5 
9.5 
1.4 
Mackerel, average, whole . . . 
71.6 
28.4 
18.8 
8.2 
1.4 
Salmon, whole 
63.6 
36.4 
21.6 
13.4 
1.4 
Salt Cod 
53.8 
26.1 
21.7 
0.3 
Salt! 
20.1 4.1 
Smoked Herring 
34.5 
53.8 
36.4 
15.8 
11.7 11.6 
Salt Mackerel 
42.2 
47.2 
22.1 
22.6 
10.6 2.5 
Oysters 
87.2 
12.8 
6.0 
1.2 
3.6 
2.0 206 
Hyqiene. 
TABLE II. — Constituents of Vegetable Foods. 
Kinds of Foods. 
Water. 
— 
gl* 
N 
En 
UTRIEN 
o 
6 
' J' 
?- 
Wood fiber. 
Mineral 
Matters. 
foods. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Per ct. 
Wheat-flour, average* .... 
11.6 
11.1 
1.1 
75.4 
0.2 
0.6 
Wheat-flour, maximum* .... 
13.5 
13.5 
2.0 
78.5 
1.2 
1.5 
Wheat-flour, minimum* .... 
8.3 
8.6 
0.6 
68.3 
0.1 
0.3 
Graham-flour (wheat) 
13.0 
11.7 
1.7 
69.9 
1.9 
1.8 
Cracked Wheat 
10.1 
11.9 
1.7 
74.6 
1.1 
Rye-flour 
13.1 
6.7 
0.8 
78.3 
0.4 
0.7 
Pearled Barley 
11.8 
8.4 
0.7 
77.8 
0.3 
1.0 
Buckwheat flour 
1.3.5 
6.5 
1.3 
77.3 
0.3 
1.1 
Buckwheat “ farina ” . . . . . 
11.2 
3.3 
0.3 
84.7 
0.1 
0.1 
Buckwheat “ groats ” 
10.6 
4.8 
0.6 
83.1 
0.3 
0.6 
Oatmeal 
7.7 
15.1 
7.1 
67.2 
0.9 
2.0 
Maize-meal 
11.5 
9.1 
3.8 
69.2 
0.8 
1.6 
Hominy 
13.5 
8.3 
0.4 
77.1 
1.3 
0.1 
Rice 
12.4 
7.4 
0.4 
79.2 
0.2 
0.1 
Beans 
13.7 
13.2 
2.1 
53.7 
3.7 
3.6 
Peas 
15.0 
22.9 
1.8 
52.4 
5.4 
2.5 
Potatoes 
75.5 
2.0 
0.2 
20.7 
0.8 
1.0 
Sweet Potatoes 
75.8 
1.5 
0.4 
20.0 
1.1 
1.2 
Turnips 
91.2 
1.0 
0.2 
6.0 
0.9 
0.7 
('arrots 
87.9 
1.0 
0.2 
8.9 
1.2 
0.8 
Cabbaqe 
90.0 
1.9 
0.2 
4.9 
1.8 
1.2 
Cauliflower 
90.4 
2.5 
0.4 
5.0 
0.9 
0.8 
Melons 
95.2 
1.1 
0.6 
1.4 
1.1 
0.6 
Pumpkins 
90.0 
0.7 
0.1 
7.3 
1.3 
0.6 
Apples 
84.8 
0.4 
0.0 
12.8 
1.5 
0.5 
Pears 
83.0 
0.4 
0.0 
12.0 
4.3 
0.3 
Starch 
15.1 
1.2 
0.0 
83.3 
0.0 
0.1 
('ane-Suqar 
2.2 
0.3 
0.0 
96.7 
0.0 
0.8 
Wheat-bread t 
32.7 
8.9 
1.9 
55.5 
1.0 
Grahain-bread 
.34.2 
9.5 
1.4 
53.3 
1.6 
Rye-bread 
30.0 
8.4 
0.5 
59.7 
1.1 
Soda Crackers 
8.0 
10.3 
9.4 
70.5 
1.8 
“ Boston ” Crackers 
8.3 
10.7 
9.9 
68.7 
2.4 
“ Oyster ” Crackers 
3.9 
12.3 
4.8 
76.5 
2.5 
Oatmeal Crackers 
4.9 
10.4 
13.7 
69.6 
1.1 
Pilot (bread) crackers 
7.9 
12.4 
4.4 
74.2 
1.1 
Macaroni 
13.1 
9.0 
0.3 
76.8 
0.8 
10. Cereal Foods. — The chief of these are wheat, 
maize, rye, oats, and rice. They are the seeds of various 
grasses, and are usually called grains. They are the most 
* Of analyses of American flours, 
f From flour of about average composition. 
The analyses of foods in Roman letters are American, those of foods in Italics 
are European. Foods and their Uses. 
207 
valuable of all food substances, because they contain so 
many of the constituents needed for life and health. 
The following table of Bell gives the usual proportions. 
TABLE I. — Constituents of Cereals. 
Wheat. 
Wheat. 
Long- 
eared 
•Barley. 
Carolina 
Constituents. 
Winter 
Sprinjr 
English 
Oats. 
Maize. 
Rye. 
Rice 
without 
sown. 
sown. 
husk. 
1.48 
1.56 
1.03 
14.5 
3.58 
1.43 
.19 
Starch ..... 
63.71 
65.86 
63.51 
49.78 
64.66 
61.87 
77.66 
Sugar (as cane) 
Albumen, etc. in- 
2.57 
2.24 
1.34 
2.36 
1.94 
4.30 
.38 
soluble in alcohol 
Other nitrogeneous 
10.70 
7.19 
8.18 
10.62 
9.67 
9.78 
7.94 
matter, soluble in 
alcohol .... 
4.83 
4.40 
3.28 
4.05 
4.60 
5.09 
1.40 
Cellulose .... 
3.03 
2.93 
7.28 
13.53 
1.86 
3.23 
Traces 
Mineral matter . . 
1.60 
1.74 
2.32 
2.66 
1.35 
1.85 
.28 
Moisture .... 
12.08 
14.08 
13.06 
11.86 
12.34 
12.45 
12.15 
Total .... 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 
The ash constituents are about as follows: — 
TABLE II. — Constituents of the Ash of Cereals. 
Constituents. 
Wheat. 
Golden 
Drop. 
Barley. 
Oats. 
(Middle- 
sex). 
Rye. 
Maize. 
(Ameri- 
can). 
Rice 
without 
husk. 
(Carolina). 
Total ash on dry grain . 
1.81 
2.66 
3.01 
2.11 
1.54 
.31 
Potash 
K20 
30.07 
12.74 
9.34 
20.42 
26.01 
17.71 
Soda 
Na2 O 
.66 
4.03 
— 
— 
.91 
— 
Sodium chloride . . 
NaCl 
3.05 
.31 
1.03 
2.78 
2.13 
3.24 
Magnesia .... 
MgO 
11.39 
7.59 
7.75 
9.23 
18.73. 
7.86 
Lime 
CaO 
5.17 
3.45 
4.22 
1.89 
1.82 
2.62 
Oxide of iron . . . 
PeO 
.19 
.34 
.36 
1.25 
.52 
.60 
Alumina 
ai2o3 
Trace 
2.28 
— 
.11 
— 
— 
Oxide of manganese Mn2 03 
Trace 
Trace 
Trace 
Trace 
Trace 
— 
Sulphuric anhydride 
S03 
3.18 
1.44 
3.10 
1.29 
1.62 
.87 
Phosphoric anhydridt 
p2 o5 
45.50 
39.11 
32.09 
48.03 
47.45 
65.36 
Silica 
SiO 
.79 
24.70 
39.56 
10.43 
.81 
1.74 
Sand 
— 
4.01 
2.55 
4.57 
— 
— 
Total 
100.00 
100.00 
100.00 
100.00 
100.00 
100.00 208 
Hygiene. 
11. The following gives an idea of the proportions 
in usual wheat-flour. 
TABLE III. —Constituents of Flour. 
Constituents. 
Household, 
Best 
Household. 
Best 
Whites. 
Starch ancl Dextrine 
G9.04 
71.05 
70.33 
Cellulose 
.52 
.70 
.77 
Sugar corresponding to cane sugar. . 
Albuminoids and other nitrogenous 
.71 
.64 
.68 
matter insoluble in alcohol .... 
9.30 
7.94 
9.40 
Nitrogenous matter soluble in alcohol 
6.83 
5.05 
4.20 
Fat 
1.06 
1.22 
1.08 
Mineral matter 
.67 
.73 
.58 
Water 
11.81 
12.67 
12.96 
Total 
100.00 
100.00 
100.00 
A part of the nitrogenous matter is represented by 
crude gluten, which can be separated by kneading the 
Hour in a little water, and then pouring a stream of 
water upon it while the kneading is continued, so as 
to wash out the starch. It also carries with it soluble 
nitrogenous principles, and albumen. Ordinary wheat- 
dour contains in all from 85 to 95 per cent of nutritive 
material. 
Bread can be prepared either from grains from which 
the husk or covering is separated, as in the usual white 
bread, or from dour in which this is retained, gen- 
erally known as brown-bread. There has been much 
discussion as to their comparative nutritive properties. 
It is true that in the husk or covering there is more of 
the fat and of phosphates or bone-making material, but 
a very thin removal of the husk can take place with- 
out removing much of this. If all is retained, rough 
particles of the husk may produce irritating effects, and Foods and their Uses. 
209 
interfere with assimilation. The amount of waste is at 
least double that of white flour bread. Brown-bread 
is often falsified, bran and a little molasses being stirred 
into second-rate dark flour. 
Whole wheat is sometimes run between rollers, and so 
deprived of any roughness which the husk might give 
it. There can be no doubt that if bread could be pre- 
pared with less removal of the covering of the grain, it 
would be a little more nutritious. 
Average wheat bread has 28.5 per cent of carbon, 
and 1.27 per cent of nitrogen, and hence one pound 
will contain 1996 grains of carbon and 89 grains of 
nitrogen. It is, therefore, at usual prices, a good stand- 
ard of nutritive, economical food. One pound of Scotch 
oatmeal has 2800 grains of carbon and 140 of nitro- 
gen, and is therefore not so economical as wheat flour. 
12. Indian-corn is a nutritious and economical food, 
and deserves, as such, far more attention than it re- 
ceives. Its nutritive value is, in carbon, the same as 
wheat flour, and its nineteen grains less of nitrogen is 
compensated for by a considerable quantity of free 
hydrogen, which is found in the fat, in which the grain 
is somewhat rich. It depends for its digestibility and 
for its relish more on cooking than does the wheat 
flour. It requires long boiling, and to be carefully 
stirred into hot water while being prepared. If thus 
allowed to boil for an hour or more, and made so as 
not to become too thick when cold, it can be cut into 
slices and used for frying, and thus form both a nutri- 
tious and savory dish. 
13. Milk is to be regarded as a leading food, because 
it contains each and all of the food constituents in the 210 
Hygiene. 
best proportions. Each pint of good milk lias 546 
grains of carbon, and 43f grains of nitrogen, with all 
needed salts. The two leading constituents are the 
casein, which makes cheese, and the fat, which makes 
butter. It is better warmed, but not boiled, when taken 
with meals, as this mingles the oil and casein more 
fully with the milk, if it has been kept standing. 
Skim-milk has only lost the most of the oil of the 
milk, and is therefore inferior only in this one in- 
gredient. At one cent per pint, Edward Smith, a high 
English authority, says of it, that there is no animal 
food which is cheaper. When used in cooking, a little 
added suet supplies the place of the cream. Buttermilk 
is equally valuable as a food, except when it is churned 
from very sour milk, or has become cheesy by age. 
Even in this state it is largely eaten in Ireland, and 
it is found that the amount of food derived from it 
in this condition is more than half of that of skimmed 
milk. 
Smith, in his dietary, insists that skim-milk, butter- 
milk, and even the whey of milk, have such value 
as foods, that, unless there is very unusual cheapness 
of other articles, they are most important additions to 
human foods. 
The whey, although having lost its fat and cheese, 
has sugar of milk and lactic acid, and is not only nutri- 
tive, but is often an aid to digestion. 
Cheese, if made of milk only, is the representative of 
the casein of the milk, with some fat, and is a cheap 
food. While a little may aid digestion, enough for a 
meal is only partially digested, so that it is doubtful if 
more than two ounces at a time is available. Foods and their Uses. 
211 
14. Meat is a form of food which, when rightly pre- 
pared, is easily transformed into our own flesh or tissue. 
In its ultimate composition it does not differ much 
from flour, and, in its albuminates, but little from 
some vegetables. There is much more water in flesh 
than in flour, although with this extracted flesh is a 
very concentrated food. Of all flesh, beef and mutton 
are the best regular foods. The evil effects which are 
so generally claimed to follow the use of pork and 
veal, says Smith, “ have not, I believe, any connection 
with the composition of those meats, but depend upon 
the imperfect way in which they are masticated and 
prepared for the process of digestion. The lean flesh of 
pork is hard, whilst the fibers of the flesh of veal are 
held loosely together, so that in the former case the 
teeth separate the fibers wdtli difficulty, and in the latter 
the fibers elude the grinding process of mastication; 
and, in both cases, the meat is swallowed in masses 
too large for the ready action of the gastric juice.” 
So much depends upon right cooking and right masti- 
cation. Inferior cuts of meat often differ in value only 
because of the absence of fat between the layers of fiber, 
and their less juiciness and consequently less flavor. 
Coarseness of fiber interferes with mastication, and 
thereby with digestion. 
In the English market, with every piece of flesh 
sold a small piece of bone is added. Bones broken and 
boiled for six or eight hours add much nutrition to 
broths and soups, because of the alkaline and other 
salts which they contain. 
Pork or bacon, although so often talked against, is 
a very important food. Bacon differs from beef and 212 
Hygiene. 
mutton only in the two facts, that the proportion 
of fat to lean is much greater, and that it has under- 
gone the process of salting, and, being dry, it possesses 
a larger amount of nutriment to a given weight than 
when the flesh was fresh. It therefore supplies more 
carbon, and thereby diminishes the necessity of bread; 
but it offers less nitrogen, and thereby renders the 
demand for milk and other highly nitrogenous food 
greater. In point of practical economy, bacon exceeds 
fresh meat. It is true of it, as of all salted meats, that 
the salt draws out the juices of the meat, and at the 
same time hardens the fiber and diminishes or takes 
away its digestibility. The fat of the pork, however, 
is not toughened by it so as to interfere with diges- 
tion. 
As pork can now be preserved without so large an 
addition of salt, and as thorough cooking overcomes 
objections grounded on the presence of parasites, which 
also exist in other foods, we believe that great care 
should be used to secure a large produce of this food, 
and a proper condition of it before salting. 
15. Eggs are very valuable as adjuncts to other food, 
since they consist chiefly of nitrogenous matter, but 
being deficient in carbonaceous material, they must 
he eaten with bread or other carbonaceous food. 
Fish may be compared with butchers’ meat by ref- 
erence to the tables already quoted. In the flesh of 
most fish, the nutritive material is largely protein. 
If they can be procured fresh, and properly cooked, 
they are a cheap and valuable food. Those not rich 
in oil need the addition of fat in frying or as dress- 
ing, but the food is highly available. Salting makes Foods and tiieir Uses. 
213 
the same variation of value as is made by the salting 
process for meats. But if the fiber is not tough, and 
the overplus of salt is removed, salt fish is both 
appetizing and economical. It needs thorough chew- 
ing. 
16. Beans deserve a very high rank among the dry 
farinaceous foods. They are far more palatable and 
available than the dry peas which are used largely 
abroad. The common bean, the kidney or haricot 
bean and the lima-bean, are all very valuable, the 
economy depending on their comparative price. The 
nutritive value of beans is higher than that of all 
other vegetables, since they somewhat exceed that of 
wheaten flour in carbon, and have more than double 
the amount of nitrogen. Bean soup, made after the 
beans have had proper soaking, and with no undue 
amount of pork, or baked beans, or beans dried after 
being cooked and ground, and used as a kind of flour 
for admixture in puddings, make a most valuable and 
economical dish. Peas have similar qualities to beans, 
but not in the same degree. 
Potatoes, as to their value and economy, need very 
careful attention from all householders. They are 
capable of furnishing a most valuable addition to bread- 
stuffs, and oils and meat; but very much depends on 
the quality of the potato and the modes of prepara- 
tion. 
In each pound of good peeled potatoes there are 770 
grains of carbon and 24 grains of nitrogen. As they 
are below the value of bread, their economy will depend 
on the relative price. 
A potato which, after cooking, cuts like soap, or is 214 
Hygiene. 
eaten cold, is not easily digested, and yields up its nutri- 
ment tardily. It is most economical to roast them, or 
to boil them with the skins on, in which case they 
should be eaten hot. Potatoes contain some valuable 
potash salts which are mostly lost in boiling without 
skins, but are retained in baking and stewing. 
17. Green Vegetables. — Cabbage, turnips, carrots, 
parsnips, and onions contain from 85 to 92 per cent 
of water before cooking; and therefore their amount 
of nutrients is small in proportion to bulk. 
Parsnips rank next to potatoes in nutriment, and 
possess 6 per cent of carbon and 0.22 per cent of 
nitrogen. 
Carrots take the next place, and offer 5.5 per cent 
of carbon and 0.20 per cent of nitrogen. 
The Swedish turnip and the onion contain 4.5 per cent 
of carbon and 0.22 of nitrogen. The common turnip 
ranks a little lower. 
Cabbage, although so much used, ranks inferior to 
these in the nutriment which a given weight contains. 
For practical purposes, all succulent vegetables may be 
classed together, and one pound of each computed to 
contain 420 grains of carbon and 14 grains of nitrogen. 
18. It is to be borne in mind that most of these vege- 
tables have gluten, as a nitrogenous food in an available 
form, which is to be taken into account in their absolute 
value and in their comparative rating. The amount 
of this found in some of them is as follows: — 
Beans (farinaceous vegetable) ... 10£ per cent. 
Cabbage 8 “ “ 
Potatoes 3 to 6 “ “ 
Red beets “ “ Foods and their Uses. 
215 
Poor wheat has as low as 9 per cent, and barley and 
Scotch oats from 6 to 7 per cent. 
Potash and soda and phosphorus are found combined 
in most vegetables; and iron is met with in carrots, 
potatoes, cabbage, tomatoes, and even in cucumbers. 
It is plain that these vegetables are to be rated at 
rather more than their food-values because of their 
juices as appetizers. Parsnips, carrots, and beets pos- 
sess much sugar in their valuable juices, and a con- 
siderable amount of other elements of nutrition. The 
same can be said of onions, which, like cabbage, seem 
to draw a large portion of their food from the at- 
mosphere, and to have something of the tonic effect 
of pure air. The essential oil of the onion is a stimu- 
lant to digestion. Cabbage resists certain kinds of 
fermentation. The tomato, half fruit and half vegetable, 
besides its general value, is of great service as an ap- 
petizing sauce. Tomatoes also, besides a trace of iron, 
contain an acid, like that of the apple. All these vege- 
tables are available as changes from the regular diet, 
and, like the fruits, as having juices whose full ad- 
vantages are to be learned only by close watching of 
effects. 
It is true of all vegetables that they are most digestible 
when well-cooked, without grease, and seasoned and oiled, 
if need he, afterward. 
19. Sugars. — These, as available to man, are found 
all ready in cereals, vegetables, and in most fruits, and 
are derived, in different forms, from the sugar-cane, the 
sugar-maple, from beets, and are in the crystallized form 
of cane-sugar. Glucose is another form of sugar of less 
sweetening and food qualities. It is found in honey, and 216 
Hygiene. 
obtained from potatoes, Indian-corn, ete. There is not 
much of it in vegetable juices. Molasses has much of it 
not derived direct from the sugar-cane, but in process of 
heating a transformation takes place. As a rule, artificial 
sugars are not economical as a part of diet. Nature 
converts the starch of many of our foods, such as bread, 
potatoes, etc., into sugar, and avails itself of the natural 
supply contained in milk, fruits, etc., so that in a perfect 
diet, for perfect health, much more sugar is not needed. 
Sugar has no nitrogen, and contains 2800 grains of car- 
bon to a pound. Smith speaks of it thus: “ Sugar is the 
first article to be cut off or discarded in times of press- 
ure, and in districts where milk is very abundant and 
cheap, its ordinary use is almost unknown. ... It is, 
however, a very valuable food, since it is most rapidly 
digested, and supplies heat-forming materials to the body. 
When, however, it is compared with wheaten flour it is 
a very dear food, since three to four times more carbon 
will be obtained for one pennyworth of flour, besides the 
nitrogen, none of which is found in sugar. It has also 
been proved that even its fattening properties, when it 
is supplied in excess of the quantity which the daily 
wants of the body require to produce heat, are not 
greater than that of starch as found in the cheapest 
grains. . . . Whilst it is a good food, it is not an eco- 
nomical one.” Children do not derive quite as much 
sugar from the starches as do adults, and therefore 
it is a little more needed by them. It is best eaten in 
the form of a pure syrup, with bread. 
20. Cookery of Foods. — In comparing the constitu- 
ents of the human body and of foods, we have seen 
that they are so much the same as to show that our Foods and their Uses. 
217 
demand for, or our acceptance of foods, depends upon 
the fact that they have in store just what is the make- 
up of the human system. Where, as in the case of 
sugar and starch, they do not reappear in the body, we 
know just how they have been converted into heat anti 
force. They do not actually appear in substance and 
deposit in the body only because they are so energeti- 
cally converted into power in the process of digestion. 
But we must not only find these materials in foods, 
but find them in such a state as that they can be 
appropriated. The foods, as stored in the animal or vege- 
table, may not be in such a state as to be appropriated by 
ordinary digestion, or the digestive apparatus may be in- 
capable of doing its work of assimilation when they are 
rightly furnished. In either case there will be failure of 
nutrition. Just now we have to do with that failure 
which may occur from the condition of the food. It is 
the great design of cookery to place food in such a sol- 
uble and digestible state as will render it most available 
to the digestive organs. In doing this, it is true, wre have 
some regard to flavors whose power over appetite and 
digestion we cannot chemically analyze. But the chief 
point is to secure that tenderness of fiber, and that 
condition of flesh-forming and heat-producing material 
contained in them, which will be most readily digested 
and absorbed. This means very different treatment for 
different substances. 
21. Thus even cooked water is in many respects different 
from unboiled water. The boiling expels the air and 
other gases always occupying the interspaces between 
the particles of natural water. The water contains in 
solution some mineral constituent, as lime, which is 218 
Hygiene. 
precipitated by boiling. Organic impurities are by this 
process driven off in the form of gases. We now know 
that minute forms of life, both animal and vegetable, 
exist even in pure water, and in much greater quantities 
in impure water, and that these are destroyed by boiling. 
This general fact does not make it necessary that water 
should always be boiled, but when we are suspicious 
of a water-supply it is well to boil the water. If it is 
aerated afterward, by pouring it from one vessel to 
another, we secure the advantage of aerated water 
without the risk of impurities. It is true also that 
tepid water, taken at the time of meals, agrees better 
with the digestion of some persons than does cold water. 
It is claimed that the Chinese would suffer much more 
than they do from the filthiness of some of their cities 
and dwellings, were it not that the ordinary drink of 
the people is boiled water flavored by an infusion of 
tea leaves. 
22. There are some articles that are made less di- 
gestible, or their contents less available, by cookery. 
Thus a fresh egg, beaten raw, with a little salt and 
sugar added, is more digestible than any form in which 
it can be cooked. 
The egg, both white and yolk, is chiefly composed of 
albumen, the yolk having added to it a peculiar oil 
and some coloring matter. 
If we immerse an egg in boiling water, and keep it 
boiling for about three minutes, we convert the white 
into a tough, hard, and indigestible mass. The yolk 
has scarcely been warmed. The outer albumen is 
hard, although we call it a soft-boiled egg. The rea- 
son is that we have kept up a cooking temperature Foods and their Uses. 
219 
of 212° F., when only 160° F. is needed to coagulate 
albumen. If the water is brought to the boiling-point 
and removed from the fire, and the egg at once dropped 
in so as to be covered by the hot water, and allowed 
to remain in the covered sauce-pan for from ten to 
fifteen minutes, it will be a soft-boiled egg, with the 
albumen, all through, in a flaky, instead of a hard- 
ened state, and so much more digestible. This, with- 
out further details, serves as an example of the relation 
of the cookery of foods to the amount of food-value 
actually derived from any given article. It well illus- 
trates what proper cookery can do to preserve or make 
palatable a most valuable food, and on the other hand 
to diminish or almost destroy its value. 
23. Since albumen exists in flesh mostly in a juicy 
form, this fact as to eggs has an important bearing on 
the cookery of all meats. 
If we desire to fully extract the juices of the meat, 
so as to make soup, since albumen is soluble in cold 
water gradually raised to a heat below 160° F., we put 
the meat in cool or lukewarm water and keep it sim- 
mering for a considerable time at a temperature below 
this point, until its soluble compounds have passed 
into the soup. Then a gentle squeezing of the meat will 
still add more to the soup. 
If, on the other hand, we desire that the nutrient 
strength of the meat be retained in the meat itself, 
we pursue exactly the opposite course. The joint is 
plunged into boiling water, so that the albumen may 
harden on its surface. If kept constantly boiling, there 
will again be too much hardening of the albumen in 
the interior; so after about five minutes of boiling, 220 
Hygiene. 
the vessel should be set aside where the water will 
retain a temperature of about 180° F. Of course it will 
take longer thus to get the boiled leg of mutton thor- 
oughly done, but the difference both in flavor and 
in nutrient qualities will repay for the trouble. Even 
the addition of salt has a special purpose, since it helps 
to coagulate the outside albumen, raises the boiling- 
point of the water, and by increasing the density of 
the water, retards the oozing out of the juices. 
When meat is stewed, the intent is to separate the 
juices from the meat and transfer them into the other 
materials of which the stew is composed. Here, again, 
as we do not wish to confine the juices, simmering, and 
not boiling, is the process. In roasted meat, on the 
other hand, the design is to retain the juices in the 
meat, and to concentrate them by evaporating some 
of the water mingled with them, and then to give 
to them additional flavor by a browning of the surface. 
These examples will suffice to illustrate how a piece 
of meat may, by its mode of cookery, be deprived of 
its nutritive qualities, or have them transferred quite 
fully as in soup, or partly as in stewing, or have them 
retained and made more digestible by the tendering 
of the fiber and the concentration of the juices, as in 
boiling or roasting. 
24. Grains, as used in various forms, are greatly affected 
by cookery. 
Rice, oftenest of, all is used without any grinding 
or kneading preparation. It is a grain that, when 
well prepared, is nearly all assimilated, and in the 
climates where not much oil is needed, must ever be 
the leading food. If put in cold water, and over a Foods and their Uses. 
221 
good fire, it is cooked by the time the water reaches 
the boiling-point. As soon as it is done, it should be 
rapidly drained, so as to rob every grain of moisture. 
It is true that it may be rendered palatable in other 
ways, but this is the kind of cooking that will allow 
the greatest amount of it to be assimilated. 
Oatmeal and maize are the other two grains which, 
after grinding, are used without kneading or fermen- 
tation by yeast. 
In cooking so simple a dish as oatmeal porridge, 
the difference between cooking it rapidly to the boiling- 
point in a few minutes, and simmering it gently for 
nearly an hour, will determine its ease of digestion, 
and the amount of it which will be assimilated. The 
same is true as to mush made from maize or Indian- 
corn. 
Bread is made from the flour or meal of grain by 
moistening it with water and mingling it with yeast, or 
gaseous matters, in order by fermentation or aeration 
to make it light, and baking it. As bread has in it 
water, albuminoids, and carbohydrates it undergoes 
important changes, which, if rightly conducted, aid in 
its assimilation. 
While the albuminoids and nitrogenous matters are 
made less soluble, they are not made indigestible. The 
starch granules are broken up and changed into sugar 
and dextrine, both of which are more digestible. When 
well masticated, the bread of fine wheaten flour is more 
digestible than most grain foods. 
25. The chief modes of preparing grains for bread are 
as follows: — 
(a) Unleavened bread, such as the corn-bread of 222 
Hygiene. 
America, or the oat-cakes and bannocks of Scotland, 
is made into a paste with water, salt being pretty freely 
added, and raised by quick heat. 
(b) Leavened or fermented bread is made by using 
leaven or yeast, and thus causing fermentation, or ris- 
ing and lightness. Thorough kneading diffuses the 
leaven, and also has to do with facilitating the chemical 
changes which take place in the mass. In this process, 
and in baking, the starch granules are closely com- 
bined with the gluten, and on the outer surface the 
starch is converted into dextrine and caromel, — forms 
of sugar. The loaf or roll is so made more easy of 
mastication and digestion. 
The difference between the digestibility of well-pre- 
pared hot bread and of cold bread is not so much in 
their composition as in the fact that the hot bread is 
more sticky, or is more apt to be swallowed without 
sufficient chewing. 
(c) Another form of raised bread is prepared by me- 
chanical means instead of yeast, and is known as 
aerated bread. Water is charged with carbonic acid 
gas, and this is so brought into a closed space, partly 
filled with flour, and so mingled with it as to cause 
lightness, by the air-diffusion and artificial kneading. 
A quick baking, in a proper oven, secures a light bread 
through this mechanical method. 
(d) Much bread in the form of hot bread or biscuit 
is made by using bicarbonate of soda and cream of 
tartar, or hydrochloric acid, or by means of bicarbo- 
nate of soda and the acid phosphates of lime and 
potash. These are mingled through the flour, and 
then .the heat liberates the carbonic acid gas in the Vegetables. 
223 
process of baking, and so secures lightness. The various 
baking-powders and self-raising flours depend on this 
method. It cannot be said that this method is inju- 
rious, but by reason of impurities in commercial chem- 
icals, or the effect of certain of these impurities on some 
digestive organs, they are not so uniformly reliable 
as the usual yeast-raising method. 
26. Vegetables. — In the cookery of vegetables, as the 
main point is tenderness, and as the albuminoids are 
a subsidiary part, the boiling cannot be kept up 
too constantly to the time when they are just done. 
The water is to be kept boiling from the moment the 
vegetables are put in. They are to be kept pressed 
beneath the water, so as to cook equally, and at the 
moment they have become tender must be taken out 
and dried if necessary. It is true that vegetables lose 
somewhat in valuable salts and in other ingredients 
in cooking, but this is the least of the evils, since it is 
necessary to soften the fiber of leguminous plants. 
The water in which peas, beans, asparagus, etc., are 
boiled is often used as a stock for soups, because of 
its flavors and slight nutrient qualities. 
The tables before quoted show the comparative value 
of these vegetables as thus secured by cookery. 
27. This brief outline of foods, and of the cookery of 
foods, will suffice to direct attention to the identity 
of materials found outside of the body with those of 
which the body is composed. While we are not able 
to explain the marvellous combination by which mental 
as well as physical power is elaborated, we are able to 
obtain most valuable indications as to what foods are 
to be chosen, how they are to be varied, and how they 224 
Hygiene. 
are to be prepared. Chemistry and the results of actual 
use now enable us to adapt foods to particular condi- 
tions, so as to secure more flesh or more vigor. It is 
just as practicable for the individual to inquire how to 
feed so as to get the best health, and the best power 
for work or for usefulness, as it is for the engineer to 
inquire wliat kind of fuel will give the most steam, and 
how this steam can he utilized so as to secure the 
greatest amount of force. 
The person who early comes to a proper consider- 
ation of these forces, their origin and the mode of 
their utilization, has made a very important step 
forward in education. Too many learn the lesson too 
late to make it wholly available. Each student and 
each worker, in any department must find out the indi- 
cations in his own case, — what is desirable and what 
undesirable, what agrees and what disagrees, how food 
and sleep and exercise are to he adjusted to each 
other, and then acquire that poise, that self-control, that 
behavior, or having the being in possession, which 
will enable him to apply this knowledge in the daily 
business of living according to the general laws of 
health, and according to those individual modifica- 
tions which his own constitution, capabilities, surround- 
ing, and his own kind of labor require. Our knowledge 
of the hygiene of digestion and assimilation, and of foods 
and their preparation, is now such as to enable us to 
greatly conserve the health and physical education of 
the people. Chapter XIII. 
DRINKS AND CONDIMENTS. 
THE chief drinks of mankind are water, milk, tea, 
coffee, cocoa, and fermented or distilled liquors. 
The need for any fluid arises from the fact that water 
is a conveyancer or medium of exchange for the vari- 
ous processes of nutrition, and for the removal of the 
secretions and excretions of the system. In one case, 
that of milk, it is the necessary vehicle for the food 
of mankind before the chewing apparatus is furnished. 
In other cases, it may or may not be used as the 
vehicle for various aliments, juices, or flavors of which it 
becomes the carrier. It has already been noted that the 
juices of grains, vegetables, meats, and fruits are a part 
of the natural water supply, as well as that which is 
furnished from the sky or in the earth as pure water. 
2. Tea, Coffee, and Cocoa. — These, although needing 
a somewhat individual study, are so allied to each 
other as to justify their consideration side by side. 
There is one organic constituent or alkaloid that is 
common to them all, and upon which, more than on 
any other ingredient, the call for or habit of their 
use depends. This essential alkaloid, as found in tea, is 
called theine; in coffee, caffein; and in cocoa, theo- 
bromine. The chemical formula given for the first 
two is C8H10N4O2 and for the theobromine C7H8N402. 
The theine-like alkaloid, found in cocoa and called 
225 226 
Hygiene. 
theobromine, is so slight a variation from the other 
two that these three, as to their stimulating alkaloids, 
are spoken of generally as identical. Their form of 
combination gives some variation as to their effects and 
as to the mode of treatment in order to secure it. 
Thus the theine in tea is in combination with tannin, 
and this fact must be regarded. Coffee is modified by 
its essential oil, and by the caramel developed in roast- 
ing. Carbon, hydrogen, nitrogen, and oxygen are found in 
each. They are all rich in nitrogen, tea containing about 
29 per cent. While tea contains little or no available 
oil or fat, coffee has from 11 to 14 per cent, and cocoa 
contains from 47 to 53 per cent. In tea there is little 
or no sugar, or material for it. In coffee, the starch, 
sugar, dextrine, and vegetable acids amount to from 15 
to 16 per cent. In cocoa there is from 4 to 8 per cent 
of starch, convertible into sugar. 
Roasted coffee has 14 per cent of albumen, but tea 
and cocoa not enough in the soluble form to be ap- 
preciated. 
As to the other nutrients, and the salts, they do 
not need comparison. While they have minute quanti- 
ties of usual nutrients, in neither would the form nor 
the cheapness lead to their use for these. Sugar and 
milk, and their warmth, add much to their alimentary 
qualities. 
3. It is the peculiar effect of the alkaloid, or essential 
principle of each, and their aroma, that inclines us to 
their use. Experiments with these, as separated have 
somewhat aided in our estimation of them. Each has 
a stimulating and restorative action on the nervous sys- 
tem, which is no doubt a little aided by the warmth. Effect of Stimulants. 
227 
In addition to the purifying effect of boiling, all these 
drinks have slight antiseptic qualities. This is especially 
true of the caramel of roasted coffee. Tea increases 
the action of the skin and the amount of water se- 
creted by the kidneys. Coffee is more stimulating to 
the nervous system, in part perhaps due to its essential 
oil. The refreshing effect of tea is more lasting. Caffeine 
given in full doses to animals will produce trembling 
and stiffness of the muscles. No depression follows the 
use of either. 
4. The effect of tea and coffee is somewhat different 
upon different persons, and is to no small degree to be 
learned by close observation. As they are not to be 
accepted as foods, in the usual sense of the word, we 
are to watch closely their effects, and to be governed 
by these, in judging of the propriety or extent of their 
use in individual cases. It is true of all stimulants 
and nervines, that the effect is somewhat modified by 
their being taken apart from food and into an empty 
stomach. They are generally best taken near or at the 
time of eating. Tea, because of the tannin it contains, 
is sometimes used as an astringent. Its action in this 
regard is not so great as in usual quantities to inter- 
fere with digestion. The casein of milk combines with 
the tannic acid, and, while diminishing the amount in 
taste, makes it more insoluble. When taken frequently 
and in large quantities, it no doubt enfeebles the di- 
gestion. This is one reason why cream is much better 
for tea than milk. 
The young, as a rule, are better off without tea and 
coffee, unless they are taken in such small quantities as 
to be merely a flavor to some warm fluid. For some, they 228 
Hygiene. 
are better at meals than cold water. Very hot water, 
made cool enough to drink by the addition of milk, and 
sweetened with sugar, is a good drink, and will not 
be found insipid to those who become accustomed to 
its use. 
5. The objections made to tea and coffee do not apply 
to cocoa. The large amount of fat and of albuminoid 
or nitrogenous substance contained in cocoa gives to it 
a real food value. The starch it contains is converted 
into dextrine in the roasting of the beans or seeds. 
After roasting, the beans are passed through a machine 
which loosens their husks or outer coat. These being 
separated, the nibs or inner pieces of the bean are left. 
It is furnished in the market in this form, or more 
generally in a powder or paste, as ground cocoa and 
chocolate. They can be had pure, although there are 
many adulterations; that with fat and starch is among 
the most objectionable. The amount of natural oil is 
an objection to many. Much of it is now removed, and 
the cocoa-butter, as it is called, is used for other pur- 
poses. Preparations of cocoa and chocolate, from which 
the oil has been removed, are to be preferred. If nicely 
prepared with hot water, milk, and sugar, the}" may, with 
much advantage, be brought into more general use. 
Our drinks have so much to do with health, and 
with that vital force we need for study or other work, 
that it is well to secure early in life definite choices in 
judgment and habits as to their use. While there are 
many who make too free a use both of tea and coffee, 
their moderate use rests upon entirely a different evi- 
dence and defence from that attempted for some other 
drinks. Effect of Stimulants. 
229 
6. Alcoholic Beverages. — Every person needs to 
know the relation that fluids containing alcohol bear 
to foods, and to individual and public health. Their 
effect on mind and morals cannot be overlooked, since 
these have to do with the welfare of the body. If they 
tend to the formation of habits which seriously affect 
health, or if they in any wise weaken that power of self- 
restraint or self-control which is at the basis of both 
health and character, the young need to be informed 
and impressed in time with the peril their use involves. 
However much spirituous liquors differ among them- 
selves, as they do in many respects, they all depend for 
their use as beverages upon the alcohol they contain. 
There is a slight food-value in some of them, because 
of the fruits or grains from which they are derived, 
and of the sugar, salts, and oils they may contain. But 
neither on the ground of value or cheapness as a food 
would they ever be sought. Alcohol is a neutral com- 
pound of carbon, hydrogen, and oxygen, which, by the 
action of acids, form ethers. The most common variety 
of it is spirit of wine or ethylic alcohol (CH4O). In 
its common definition, it is that inflammable, volatile, 
spirituous liquid which is the intoxicating principle in 
spirit, wines, and beers. 
7. Liquors containing alcohol are generally spoken 
of under two classes. These are the fermented liquors, as 
wine, beer, etc., and distilled liquors, as brandy, whisky, 
rum, etc. Fermented liquors are said to be fortified when 
some distilled liquor is added thereto, either to pre- 
serve them or to make them more intoxicating. This 
is very frequently done. 
Wines have various acids, glycerine, and a little albu- 230 
Hygiene. 
minous substance. Beer contains, besides its alcohol, 
carbonic acid, volatile and fixed oils, malt extract, with 
a little starch, sugar, and albuminous substance, hop, 
resin, or other added bitters, and various salts. Pure 
vinegar is a better acid for health, when needed, than 
any of those from wines or beers. 
Brandy is a spirit derived from the distillation of 
wine, or is made artificially by adding various sub- 
stances to proof spirit. Rum is distilled from fermented 
molasses or inferior kinds of sugar-cane. Whisky is a 
spirit most frequently made from grains, as corn, rye, 
etc. It is also made from vegetables and fruits. Gin is 
a spirit made by diluting proof spirit and flavoring it 
with various substances. Any or all of these can be 
made artificially nearly like the distillation, so that they 
are not to be rated as necessarily falsifications.1 
There are also many imitations and fraudulent prep- 
arations. Names do not represent distinct vintages or 
distillations so often as they represent the skillful combi- 
nations of various dealers. 
8. It can be said of all alcoholic liquors, that there 
is nothing in them so desirable as to make it worth 
while to use them unless it can be shown that the 
alcohol is needed. When we come to study the relation 
of alcohol to foods, first of all we are impressed by the 
fact that it is not found in nature, as are such foods as 
are essential for the maintenance of life and health. 
No analysis of foods ever finds it present in them as 
an article to be taken into the human system. If it 
had any such food value as was once claimed for it, 
1 See Blythe’s Manual of Practical Chemistry, and Prescott “ On the 
Chemical Examination of Alcoholic Liquor.” Effect of Stimulants. 
231 
this omission would have been a most surprising one. 
When we turn to the physiology of digestion, and of 
the appropriation of foods in the system, we find noth- 
ing whatever to indicate that it was ever intended to be 
used by mankind as a food. Every advance in chemistry, 
and in the knowledge of the relations of food to human 
force and vitality, has been an advance away from the 
recognition of alcohol. Such authorities as Liebig, Mole- 
schott, Pettenkofer, Voit, Konig, Beneke, Meinert, Payen, 
Frankland, Playfair, Lewes, Smith, Parkes, Prescott, 
Nichols, and Atwater give it no place in any standard 
daily rations. 
9. Before chemistry assigned alcohol its proper place, 
experience had classed it among the toxics. Persons 
affected by it were not said to be fed overmuch, but 
to be intoxicated. Toxic is the Greek word for poison. 
We can turn to no book to-day, in chemistry or hygiene, 
and find it treated among the articles of food. If 
we have regard to the convenient division of nitrogen- 
ized or flesh-forming foods, we soon find that it has 
no nitrogen, and therefore cannot be arrayed in this 
class. If we look for it among the heat-producing 
foods, we find that it does not respond to the laws 
of animal combustion, either by producing force or 
increasing heat. Notwithstanding the sensation of heat 
produced by its contact with the digestive track, or 
from other causes, the thermometer and other tests 
show that it produces a slight reduction of temper- 
ature. 
In common with opium, chloral, hasheesh, and some 
other stimulants, narcotics, or nervines, alcohol has 
some temporary action where there has been a breach 232 
Hygiene. 
of natural law by which the system has been thrown 
into an abnormal condition. By such momentary effect 
these steal their way into recognition so as to have been 
called deceptive foods. They create a habit which is 
interpreted by the willing subject into a demand. 
10. As a rule, the serious fact in reference to alcohol 
is that it interferes with nutrition. It not only lacks 
food value of its own, but it detracts from the value 
of real foods. It so affects the organs which have to 
do with the assimilation and distribution of food, that 
they are incapacitated for or are disturbed in the per- 
formance of their functions. 
Experience has preceded science in crossing it from 
daily rations. This is the more significant, because 
the tables of food intended for soldiers, for sailors, 
for those in institutions, and for invalids, have been 
studied out by the very highest authorities, and have 
been tested by the most exact experience. It has been 
while in search after the best methods for getting the 
most intense force and power of endurance out of men 
in national service by sea and by land, that this evil 
spirit has been cast out. All other considerations 
have been thrust aside, and on this material basis 
alcohol has been retired from service. Where con- 
tinuous power is desired for efficient use it has no 
place. In training for athletic sports or manual 
contests, it is rigidly excluded from the dietary even 
of those who have been accustomed to its use. It 
utterly fails to be a nutrient, or to answer the purposes 
for which foods are intended. In view of its appalling 
effects on society, even if it were a food it would need 
to be proven to be a necessary food. It accomplishes so Effect of Stimulants. 
233 
much injury to human health and life, that it ought 
to be prohibited from use. Even rye would be pro- 
hibited from use if no rye could be had which had 
not ergot in it, and if the disease known as ergotism 
came to be prevalent among the people, as is disease 
from alcohol. 
11. As to the effect of its use upon human health and 
vigor, so fearful is the record, and so repeated and 
almost universal is the testimony, that we need not to 
report much of it here. Perhaps the most convincing 
recent evidence is that of the returns of vital statistics 
of the Registrar-General for England and Wales, for the 
last ten years from 1870 to 1880 inclusive. These are 
contained in the supplement of the Forty-fifth Annual 
Report (1885), in which are tabulated the facts as to 
two million six hundred and seventy-nine thousand 
four hundred and sixteen deaths. These are the results 
of unimpassioned figures, gathered outside of the records 
of Reform Societies. 
“ The mortality of men who are directly concerned in 
the liquor-trade, as brewers, innkeepers, publicans, inn and 
hotel servants, and maltsters, is appalling. The comparative 
mortality figures are as follows, 1,000 being used as a stand- 
ard : Brewers, 1,361; all dealers in spirits, wines, or beer, 
1,521; inn and hotel servants, 2,205. For maltsters, who are 
only concerned with the materials and not with the liquor 
itself, the figure is 830.” 
The report proceeds as follows: — 
“It is well, whenever the opportunity offers itself, to test 
the accuracy of our death-rates by comparison with data 
derived from independent sources, and in the case of the 234 
Hygiene. 
innkeepers and publicans such comparison is possible. 
By the experience of the Scottish Amicable Life Assurance 
Society (1826-1876), the mortality of males occupied in 
this business was 68 per cent in excess of the actuaries’ 
or healthy male-table, and 49 per cent in excess of the 
English life-table. This result tallies very closely with 
figures in our table, where it appears that the mortality 
of the innkeepers and publicans is 52 per cent above the 
present mortality of all males. 
12. “That this terrible mortality is attributable to drink 
might be safely assumed a priori, but the figures render it 
incontestable. The mortality attributed to alcoholism 
itself is far higher for innkeepers and publicans than for 
any other industry, and more than five times as high as 
the average; that for brewers falls far short of this, but 
nevertheless is the next highest to that of innkeepers, with 
the single exception of cabmen. Under the heading ‘ liver 
diseases’ the mortality of innkeepers is no less than six 
times as high as the average, and more than twice as high 
as that of brewers, and of butchers, who come next in order 
in this respect to innkeepers There are, in short, no 
organs apparently that are not more or less seriously dam- 
aged by the excessive use of alcoholic drinks, though the 
liver appears to suffer the most. 
13. “It may also be worth noting that a comparison 
between Mr. Neison’s figures and our own comparative 
mortality figures shows that a large proportion of the 
innkeepers and publicans, and of the brewers, must be of 
temperate habits; for whereas the comparative mortality 
figure of innkeepers in our table is 1,521, and that of 
brewers is 1,361, that for recognized intemperate persons, 
according to Mr. Neison’s data, would be 3,240.” 
Their desire for profitable business often helps to re- 
strain innkeepers from drunkenness. While the tables Effect of Stimulants. 
235 
show the greater evil of distilled liquors, the wine and 
beer death-rate is enormous. 
Such is the excess of death-rate among those whose 
business interests help to restrain them from drunk- 
enness. 
At the same standard, the mortality figure for clergy- 
men shows the contrast of 556; for gardeners, 599; 
for farmers, 631; and for agricultural laborers, 701. 
14. In addition, the statisticians say that the excessive 
mortality in many other callings, as that of cabmen, 
etc., is one to be accounted for by the use of alcoholic 
liquids, although this is not stated as the cause. Here 
are some of the statistical comments: — 
“ Commercial travelers, who lead mostly an out-of-door 
existence, have a mortality of 948. That a very consider- 
able proportion of the mortality is due to this cause is ap- 
parent when it is noted that, under the headings Alcoholism, 
Liver Disease, Gout, Suicide, the mortality figures for this 
occupation come very high up on the list. The death-rate 
of tailors, 1,051, and that of shoemakers, 961, are both high. 
While both trades are sedentary, and somewhat unhealthy, 
much of the excess arises from those diseases which point 
to alcohol as a cause.” 
These are but specimens of very many other employ- 
ments in which the statistical record points to an excess 
of diseases in which, in the opinion of the statisticians, 
the high proportion is mostly to be charged to the 
habitual use of alcohol, and often by those who were 
not regarded as intemperate. 
15. Induration of portions of the nervous centers, 
congestion of the respiratory organs, and shrivelling 
and thickening of the coats of the stomach, are not un- 236 
Hygiene. 
usual results of the frequent and habitual use of small 
quantities of alcohol. Still more serious is the effect 
upon the kidney and its functions. The power of alco- 
hol to act upon the vaso-motor nerves of the capillary 
system, and to produce engorgement in minute vessels, 
is plainly shown in the reddened face and changed com- 
plexion of many habitual users who are not called exces- 
sive drinkers. The varied forms of renal disease which 
now destroy so many in middle life, or reduce them 
to invalidity, generally result from irritating substances, 
which find their way into the renal vessels. No irritant 
so frequently has this effect as alcohol. So marked and 
general is its effect in the way of inducing congestion 
of the capillary circulation of the system, and of most 
of its organs, and their subsequent destructive changes, 
that it has been well-termed by Dickinson the very 
“ genius of degenerations.” The stomach, the liver, and 
the kidneys are generally the first organs to be em- 
barrassed in their functions by it. It then goes on to 
alter their structure so as to embarrass or suspend their 
service. One of the most constant and important reve- 
lations, both of pathology and of statistics, is that this 
occurs so uniformly in those who have been regarded 
as only moderate drinkers. 
How the brain and the nervous system become 
involved in the disturbance is too well known, and too 
frequently attested by what we hear and see in the 
daily wTalks of life, to need extended comment. Alcohol 
retards the normal chemical changes which are essen- 
tial to the processes of growth and repair. We need to 
give to the constructive forces full play. These are not 
stimulated, but blunted by alcohol. We cannot sue- Effect of Stimulants. 
237 
cessfully operate this wonderful machinery of life by 
forces which disturb circulation, disorder the nervous 
system, and embarrass vital organs both in structure and 
function. 
16. When we come to examine into the different forms 
of alcoholic mixtures we find them differing in their 
injurious effects as they differ in the amount of alcohol 
they contain. We of course cannot expect so rapid 
results from cider and beers, with from 4 to 10 per 
cent of alcohol, as we have from wines of from 9 to 26 
per cent; and from brandy, whisky, and gin, with their 
50 to 60 per cent of alcohol. It is for the alcohol in 
them that they are used, and it is its use which consti- 
tutes the peril to health and to life. If needed, like am- 
monia, in prolonged faintness, or like the goad or the 
whip for the horse out of the reach of food, let the phy- 
sician so decide. But because it is sometimes prescribed 
as a medicine, it has no claim for any ordinary use. 
17. The deleterious effects of all alcoholic liquids have 
so impressed most governments that restrictive meas- 
ures have been adopted as to the sale of such liquors, 
and their sale entirely prohibited or discouraged, so 
far as minors are concerned. Many who will not prac- 
tice total abstinence for themselves are in favor of bring- 
ing up men and women entirely without it for at least 
twenty-one years. The foods which are found adapted 
to the first twenty-one years of life are sufficient for the 
rest of life. 
18. Against the use of liquids containing alcohol in 
any form must be urged, not only that they are not 
needed as foods, but that their use is likely to create an 
appetite for them which is dangerous to health and to 238 
Hygiene. 
life. In all the grades, from so-called moderate use to in- 
tensest intoxication, alcohol is fraught with fearful risks 
to health and life, as well as to character and success. 
However proud we may be of our own powers of resist- 
ance, the universal testimony of experience is, that what- 
ever tends to weaken our self-restraint is to be avoided. 
Fluids containing alcohol have shown such a wondrous 
ability to break down this power of self-control, and for 
creating a desire and appetite for such drinks, that, more 
than all other influences combined, they have overcome 
the resistance of the will, and proved the allurement and 
destruction of thousands. 
Those who think they will stand, and those whom 
others have thought would stand, have fallen by multi- 
tudes. He who would do himself no harm must not 
run such a risk. The loss of self-control is a bodily as 
well as mental and moral infirmity often seen to pass 
from one generation to another. In any case, it in- 
volves in its consequences many more than ourselves. 
Hygiene has no more imperative law, and no more 
persuasive words in behalf of health, than to say, “ Touch 
not, taste not, handle not.” Character, education, health, 
happiness, and the hope of success, demand that life 
should be begun and carried through without indul- 
gence at such a peril. It is a sad misnomer to call it 
drinking each other’s health to drink alcohol. The 
fountain of health has not, and requires not, any such 
admixture. 
19. Condiments. — There is a class of substances taken 
into the mouth which do not admit of classification 
with foods, but which have, nevertheless, some relation 
to digestion, and to the nutrition of the system. Some Effect of Stimulants. 
239 
of them are a hindrance thereto or an interference 
therewith. 
In this class may be ranked the various peppers, cat- 
sups, and spices, essential oils and tobacco. We do 
not include among these common salt, since it supplies 
the blood with sodium chloride, one of its normal and 
necessary constituents, and also probably aids the stom- 
ach in the formation of its digestive juices. 
It is also true of some of the condiments, that they 
have a slight food value. Thus mustard is a seed 
which has slight nutrient properties. But we speak 
of several of these as condiments because they are 
chiefly used as flavors, or from habit, or as stimulants 
to digestion. 
Mustard, cayenne pepper, horse-radish, and ginger may 
be spoken of as those most used in their original forms 
as well as in combinations. 
Epicures have studied some of these with great care, 
and chemists have sought to ascertain the secret of 
their excitation. 
Olives, for instance, are claimed to stimulate the 
gustatory nerve, and the upper portion of the throat 
and epiglottis, and so to increase appetite. 
Cayenne pepper, and some others, act upon the inner 
lining of the stomach, and temporarily increase the 
flow of gastric juice, so that they may meet the emer- 
gency of over-eating at the peril of ultimate injury 
It must be said of the most of these condiments, that, 
before they come into general use in the case of any 
one individual, he or his physician should be able to 
give some good reason why they are needed. For we 
know as to these, as well as some other articles, that 240 
Hygiene. 
such over-taxing of organ or function creates a desire 
and a habit, and what was not a natural appetite be- 
comes one. Hence the habitual user will be able to 
take them in such strength as would be unpleasant 
or even impossible for a person not accustomed to 
such use. 
20. Black pepper, with its slight pungent and aro- 
matic taste, shows by its ash unusual value as con- 
taining valuable salts, and a pretty constant quantity 
of phosphoric acid. Potash, soda, magnesia, lime, 
sulphuric acid, and a trace of iron are found. This 
gives to it a much more important place than that 
occupied by most of the other condiments. White 
pepper is the same berry, with a greater removal of 
its black husk or covering. Cayenne pepper, although 
in so frequent use in many sauces and catsups, is a 
direct and severe irritant. It is the cause of many 
cases of dyspepsia and other forms of gastric impair- 
ment. 
Mustard, as noticed, has a small food value, and its 
acrid character is not so persistent as that of many 
other condiments. Such a mild irritant may be of oc- 
casional service. Thus a hungry man may be so situated 
as to have to eat a piece of tough meat, or eat nothing. 
No doubt thorough chewing, arid a little mustard upon 
the meat, will aid the stomach in a digestion, which 
would otherwise be incompetent. These are the whips 
which may make indigestible things partly digestible, 
and give to exhausted stomachs a little more activity. 
But how much better it is to use digestible food and 
to have a capable stomach. 
Ginger has much starch and gum, and owes its pun- Effect of Stimulants. 
241 
gency to a volatile oil, and an aromatic, acrid, soft 
resin. 
Horse-radish is a root which is a pungent stimulant, 
and which has a slight nutritive value. It is rather 
more irritant to the stomach, and for this reason not so 
good for general use as either black pepper or mustard. 
As an appetizer, it is better than either. 
Curry powders are mixtures of various condiments, 
such as ginger, garlic, black pepper, coriander-seed, etc., 
and can only be rated by the character of the ma- 
terials used. Their first use was as a dressing for rice, 
to render it more palatable, among the natives of Ceylon 
and India. They have been imitated in various forms 
by Europeans. 
Catsups and sauces, as now so extensively used, are 
composed of fruits, flavors, and condiments in order 
to cover the taste of some foods, to give special flavor 
to others, and to stimulate the appetite and digestive 
apparatus. It can be said of them, as a whole, that 
the prevailing use of them is excessive and very inju- 
rious. It is probable that the increase of diseases of the 
stomach and digestive apparatus, and especially of the 
kidney, are largely attributable to the use of so much 
of this kind of unnatural stimulation, but especially 
to those preparations made very hot with peppers and 
acids. 
Delicate and appetizing flavors, such as those of 
fruits, acids, and oils, can be obtained without all this 
confection of irritants. Williams, in his recent Chem- 
istry of Cookery, is so emphatic as to say that “thou- 
sands of poor wretches are crawling miserably to their 
graves, the victims of the multitude of maladies of 242 
Hygiene. 
both mind and body that are connected with chronic 
incurable dyspepsia, brought about by the use of cay- 
enne and its condimental cousins.” 
21. Tobacco. — It may seem strange to some, for us 
to place this among condiments. But it is an aromatic 
plant and leaf, and probably its sweetness and slight 
acrid taste, its stimulus and its power to appease 
hunger, had at first more to do with its use than any 
other cause. It has been variously claimed to be a 
food, a tonic, a condiment, a stimulant, a nervine, 
and an intoxicant. It is when we turn to a materia 
medica, or to some work on toxicology, that we find the 
fullest account of it. Its first free use generally causes 
giddiness, trembling of the limbs, faintness, depression, 
sickness of stomach, and cold sweats. The pulse is 
weak and quivering, the breathing hurried or embar- 
rassed, and the vision impaired. In toxic doses, the 
action is on the central nervous system, producing 
failure of respiration. If the chewing or smoking has 
not been very excessive, the ordinary symptoms soon 
pass off. If its use is much less, or if a toleration of 
it is acquired, it acts as a beguiling sedative. 
22. Whatever may be the ultimate accommodation of 
the system thereto, as with alcohol, a class of symptoms 
very different from those from the use of milk or meat 
or cereals or fruits tells us that it rightly finds its clas- 
sification among articles unfriendly to the best health 
or to the nourishment of vital forces. Its most decided 
effect is upon the functions of organs rather than upon 
their structure. As a rule, it is not near so apt to 
make change of structure as is alcohol. Yet permanent 
changes, especially to blood-vessels and the nervous Effect of Stimulants. 
243 
system, result therefrom. Woodman and Tidy, in their 
volume on Forensic Medicine and Toxicology, speak thus: 
“ Excessive smoking has proved fatal, as in the cases 
recorded by Gmelin, when two men smoked seventeen 
and eighteen pipes respectively at one sitting. Mr. 
Smith of Sheffield records two cases of paralysis of the 
portia dura directly caused by hard smoking.”' There 
is a general testimony that dyspepsia, heart palpitation, 
and nervous symptoms often result therefrom. Its evil 
effect upon young persons has been accurately set forth 
by Dr. Decaisne,1 and Dr. A. C. Gorgas,2 Medical In- 
spector, U. S. N. This testimony is the more significant 
because there was a return to the use of tobacco on 
the part of the students of the Naval Academy, but 
the contrasted facts caused a subsequent renewal of the 
order to desist from its use. The evidence has been such 
from other sources that a prohibitory law applicable to 
youths has been enacted in Germany. While during 
the growing period of life all are more susceptible to 
the evil effects of tobacco, those of full age are affected 
in a milder degree. There is a constant tendency of 
the habit to increase. 
23. Even among those who have the belief that the 
moderate use of tobacco does not injure all persons, there 
is such agreement as to its effect upon the young, that 
most of them favor laws which make it a punishable 
offence for those under age to use tobacco in any form. 
There is reason to believe that our young population 
is being greatly injured thereby, and also that the use of 
tobacco has become so general, and often so excessive, 
1 British Medical Journal, September 26, 1868. 
2 Am. Pub. H. Asso., Vol. VII., pp. 230-240. 244 
Hygiene. 
among adults as to be traceable in special injurious effects 
upon them and their descendants. Tobacco-smoking in- 
creases pulse-rate. Both in chewing and smoking there 
is an unnatural stimulus of the salivary glands. Their 
office as aids to the first process in digestion is inter- 
fered with. While it is true that the evil effects of very 
occasional smoking are transitory to many, it is equally 
true that the excess in the habit which generally occurs 
makes in time a permanent impression upon the nervous 
system. 
Its effect in checking growth is unmistakable. So far 
as the young are concerned, it is doing more harm to 
bodily health than alcohol. A substance which will 
produce such profound impression as it does when first 
used, and which has caused death when applied for a 
long time to a raw surface on the body, and which has 
by its irritation induced cancer, surely ought not to be 
in ordinary use among mankind. 
24. The cigarette has been found to be even more harm- 
ful than the other forms of smoking. Besides many evils 
which its use involves, not the least is one already noted 
as to alcohol. It not only becomes a habit that it is hard 
to abandon, but the very failure which so many make in 
their efforts to quit its use shows too plainly that it un- 
dermines the power of self-control, and so is a weakening 
of that vigor of trained will, of that mastery of self, which 
is a part of the physical as well as of the intellectual wel- 
fare and prowess of manhood. As an interest both of the 
individual and the state, the use of tobacco in any form 
by children should be prohibited under proper penalties. 
As a matter of public and personal health, and in the 
interests of the vigor of the coming generation, this 
restraint is demanded. Effect of Stimulants. 
245 
Some of the States have already passed laws prohibit- 
ing the sale of tobacco to those under sixteen years of 
age. 
There seems to be good evidence that modern modes of 
life, and the pressure of excessive business, incline many 
to indulge in that class of substances which produce a 
slight exhilarating effect, followed by a calm such as 
occurs in the first stage of narcotism. There is great 
occasion for the young to guard themselves against all 
plausible excuses for any of these indulgences. We have 
never known any one to regret abstinence from them, and 
have known very many, in the moderate use of some of 
the milder forms of excitants and sedatives, to be earnest 
in advising against the acquirement of such habits. Chapter XIV. 
MODES OF HEATING. 
THE first division of the subject of Heating is into 
what are called natural and artificial systems. 
The truly natural system is where we depend upon the 
natural warmth of the body and the heat derived from 
the sun. Clothing and change of position are merely 
our methods of adapting ourselves to changes, and are 
found sufficiently available under various circumstances. 
While these cannot be entirely depended upon, they 
are nevertheless to be emphasized. Those who build 
houses with a southern exposure, and with windows 
giving good access to light and heat, and yet inter- 
rupting draught, have practically carried out this idea. 
Clothing, and proper changes of clothing, and the use 
of such garments as can be easily put on or off at 
pleasure, are to be considered. It is fitly urged, that 
we may become too dependent on such forms of arti- 
ficial heat as are furnished by fire. 
2. It is always to be remembered that the body 
itself is a heat-producer, and that exercise and care of 
the skin, and proper quantities and kinds of food, and 
good sleep, have much to do with the generation and 
utilization of heat. We must not educate ourselves 
or our children to be more dependent on fire heat 
than is necessary. Those who too constantly hover 
around the stove, or who so receive heat as that one 
246 Modes of Heating. 
247 
side of the body is overheated and another part ex- 
posed to cold or draught, are not enough impressed with 
the need of availing themselves of the strictly natural 
sources of heat to a degree that shall limit the demand 
for purely artificial methods. Where the thermometer 
is at 70° F., and here and there a person feels too 
cool, there must be inquiry as to any improper source 
of draught, or else such person should have more 
clothing, more food, or better health. 
Our need for special sources of heat arises from the 
variations of actual temperature, and from the necessity 
of surrounding ourselves with houses in which there are 
many artificial arrangements. Besides the heat con- 
tained in our bodies, warmth is conveyed to us by one 
or all of the three methods of radiation, conduction, 
and convection. 
3. Radiation. — Radiation is the giving off’ of rays of 
heat from a heated surface. The rays diverge in straight 
lines from every part of a heated surface, and from 
minute depths below the surface of hot bodies. The 
radiation may be increased by increase of the surface 
and by improving the nature of the surface. Radiation 
takes place in vacant space, that is, in a space contain- 
ing no form of matter which we can weigh, as well as 
in the midst of certain media called diathermanous. Air, 
glass, and other bodies, which, in general, freely allow 
light to pass through them, are examples of such dia- 
thermanous bodies. 
Conduction. — When heat is communicated from 
molecule to molecule of a body, while the molecules 
retain their relative places the process is called con- 
duction. This process is illustrated in the action of 248 
Hygiene. 
most solid bodies, especially the metals, when one 
portion of such bodies is raised in temperature above 
the other portions, by being brought in contact with 
a hot body. When one end of a poker is thrust into 
the fire, the temperature at the end is raised by the 
fire and the process of conduction is at once set up. 
The conducting power of different substances is very 
different. Thus, that of copper is 89.92, while that of 
iron is 37.43, and of zinc 36.30. 
Convection. — In general, when liquids are heated, 
the portions first heated become thereby expanded, and 
so rendered specifically lighter than the remaining 
portions. Owing to the almost perfect freedom of 
motion among the particles of such bodies, the ex- 
panded portions are displaced upwards, while the 
heavier particles sink down to take their places, and, 
in turn, become heated and rise in like manner. This 
process of heat diffusion is called convection. 
Where there is reliance on natural heat, the build- 
ing or room is so located as to command the greatest 
amount of heat from the sun and the least wind, also 
the laws of conduction and non-conduction are recog- 
nized, and the materials, and even the colors, used for 
the room are such as will secure for it the most heat 
without any artificial source of heat. 
4. The most usual methods of artificial heating are 
as follows: 
I. By heating the air of the room. 
II. By heating air outside of the building or room, 
and conveying it into the room. 
The sub-divisions of the first method are chiefly 
these: Modes of Heating. 
249 
(a) By fire in a fireplace, or its equivalent. 
(b) By fire in some form of stove. 
(c) By radiators, or pipes heated by hot air or hot 
water or steam, and located in a room, but heated 
from the outside. 
Of the second method we have the following varie- 
ties : 
(a) By furnaces, the heated fresh air of which is 
introduced through registers. 
(b ) By radiators of various forms located outside of 
the rooms, heated by various methods, over which fresh 
air flows, and, being warmed, is let into the rooms. 
The general objection to all forms of the first method 
is that it involves the heating of air which is in the 
room, and so of air which is undergoing deterioration. 
We shall see, however, that this statement admits of 
some modifications. The general recommendation for 
the second method is that it admits of the introduction 
of air properly prepared for breathing. As a rule, it is 
more expensive, although in a matter so affecting health 
this should not have too large consideration. 
5. Under the head of heating by heating appliances 
in the room, our first example is the fireplace, in direct 
connection with the chimney, with its wood or coal fire. 
This is admitted as being a healthful mode of heating. 
The fire and the chimney thus become ventilators, by 
drawing toward themselves the air of the room, which 
is re-supplied from various cracks and crevices. Where 
there is a very strong draught, it may occasion rapid 
currents in the room. The chief objection to a fireplace 
in the chimney is, that it is difficult to secure an amount 
of heat sufficient for an entire room. The only heat 250 
Hygiene. 
secured is that by radiation. Much heat goes up the 
chimney, and the consumption of fuel is large in pro- 
portion to the amount of heat produced. 
To increase the throwing out of the heat, and to pre- 
vent so much going up the chimney, various plans have 
been devised. One of the earliest of these was the Frank- 
lin fireplace heater, by which it was sought to deflect 
more of the heat into the room. Changes in the throat 
of the chimney, and in the mode of setting the fireplace, 
have also been made, in order that less heat might 
be drawn up, and yet a proper draught be secured. 
The brightness of metals and other choices of radiating 
surfaces have been made in order to throw out the heat 
into the room. 
So valuable has the fireplace proved as a means of 
ventilation, and so available is it also as a supplement 
to other modes of heating, or for mild cr damp weather, 
that there are those who, regardless of what may be the 
other particular modes of heating, advocate the fireplace 
for ventilation. 
6. The next mode of heating is by fire in some form 
of stove. Here the air for draught is drawn from the 
room, thus, like the fireplace, inducing an inflow of 
air from without. By radiation and conduction heat is 
distributed through the room, and thus the air that is in 
the room is heated. With the best form of heating appa- 
ratus, and proper management, this mode of heating 
is compatible with purity of air. The value of the fire- 
place and of the stove is thus illustrated by Prof. C. O. 
Curtman: —■ 
“ Using an ordinary stove, and selecting as fuel anthracite 
which contains about 98 per cent of pure carbon, we find that Modes of Heating. 
251 
for every pound of fuel burned, two and two-thirds pounds 
of oxygen, measuring about thirty-two cubic feet, are con- 
sumed. This corresponds to nearly 160 cubic feet of air. As 
much air escapes through the chimney unburnt, we need 
not wonder that Regnault’s experiments led him to nearly 
double that amount, and assume that 312 cubic feet of air 
are required for every pound of anthracite burnt in a stove. 
“ A school-room twenty by thirty feet in extent, and 
twelve feet high, contains 7,200 cubic feet of air, weighing 
about 540 pounds. If, during a cold winter day, 300 pounds 
of coal are burnt in the stoves of this room, there will be 
(according to Regnault) 93,600 cubic feet of air, weighing 
over 7,000 pounds, passing through the stove into the 
chimney. In other words, by the mere automatic ventila- 
tion produced by the burning of the fuel, the room, con- 
taining 7,200 cubic feet of air, must be emptied and refilled 
thirteen times in a day; but as the period of active firing 
does not usually occupy more than nine hours (from 7 a. m. 
to 4 p. m.), the air is emptied and replaced about once in 
every forty minutes during school hours. Within these 
forty minutes fifty children would inspire about 600 cubic 
feet of air, from which they would remove about 6 cubic feet 
of oxygen. The rate of ventilation in such a room, pro- 
duced automatically by an ordinary stove consuming 300 
pounds of coal, is therefore more than sufficient for even 
a greater number of occupants, and, in ivarmer days, when 
only one-fourth of the fuel is consumed, ventilation will still 
be active enough for all purposes.” 
This, of course, will not be true, to the full extent, 
if the stove is air-tight, except in that portion of the 
room near where air for draught is admitted. But with 
this frequent aid, and if the stove door be often open, or 
the space not tight where the pipe enters the chimney, 
much ventilation is secured. 252 
Hygiene. 
7. Several points need to be carefully guarded. First, 
if, in this method, a good draught and perfect combustion 
are not secured, much of coal-gas and its compounds pass 
into the air of the room. These consist of carbonic acid, 
carbonic oxide and sulphur, and other compounds, and 
much deteriorate the air. Where an attempt is made to 
moderate or regulate draught by a damper, this often 
adds to the evil. If, on the other hand, the stove be- 
comes overheated, or is loose-jointed, carbonic oxide comes 
through the joints of the stove or through the heated 
metal, and deteriorates the air by its poisonous qualities. 
Carbonic oxide is always formed where the supply of 
air for draught is insufficient. Headache and lassitude 
are more frequently owing to this than to a general 
foulness of air. While base-burners, as they are called, 
do not let out much gas in filling, they need to have 
good draughts. They do not aid much in ventilation. 
Pipes or stove-flues, filled vTith soot or dust, often im- 
pair the draught in good chimneys. 
If the heat for warming the air is to be generated in 
the room, it is very important that there shall be perfect 
combustion to an extent not to allow any gas to enter 
the room from the stove. This presupposes an adequate 
supply of air and a good draught of the smoke-pipe or 
chimney. 
Where the draught is otherwise complete, the turning 
of dampers, or the opening of the stove door, while 
putting in the coal, may cause the presence of gas in the 
inbreathed air. A great deal of trouble with stoves and 
furnaces comes from imperfect draught of chimneys, or 
from too small an air inlet to the coal. Excess of fuel 
over air produces imperfect combustion by lack of oxy- Modes of Beating. 
253 
gen, while excess of air over fuel produces imperfect 
combustion by diminution of temperature. 
8. Supposing that a proper supply of fresh air is in 
some way reaching the room, and that the heating appa- 
ratus in the room is heating it, a question arises as to the 
dryness of the air, since our sensation of heat is affected 
thereby. One effect of heat upon air is to raise its point 
of saturation. One cubic foot of air, say at thirty-two 
degrees, is capable of containing a certain amount of 
moisture, and no more. If we raise it to a heat near 
that of the human body, it is capable of containing 
much more, and consequently absorbs moisture from 
everything that contains any. The heating of the air 
does not dry it in the sense of extracting moisture from 
it; it only increases its capacity of containing water, 
thereby rendering it more absorbent or thirsty. 
Our difficulty here arises from the fact that air may be 
too rapidly increased in its capacity for moisture on the 
one hand, or may bo saturated with moisture on the other. 
When the temperature of air cannot be diminished 'with- 
out depositing water upon the walls or window-panes, 
or without its appearing as a mist, it is said to be satu- 
rated. If the temperature of saturated air be raised, it 
will become drier to the senses, and will immediately 
begin to take up water which is exposed to it. 
Air is dry or moist, not in proportion to the water it 
contains, but in proportion as it is more or less removed 
from the point of saturation. The point of saturation 
rises more rapidly than the temperature. 
9. A glass tumbler filled with cold water in summer 
is soon bedewed with moisture, because the air around 
it is cooled, and its moisture precipitated upon it; the 254 
Hygiene. 
same occurs in winter if the tumbler is brought into a 
close room in which many persons are assembled, and 
in which the air is loaded with the accumulated vapor 
exhaled from the lungs and skin. For the same cause, 
in winter the cold windows of a crowded room, not 
provided with efficient ventilation, are constantly cov- 
ered with minute drops of water, which soon collect 
and run down the glass in streams. 
The highest point of the thermometer at which vapor 
begins to be deposited by the air is called the dew-point; 
it is the point at which dew begins to form. The humid- 
ity of the air is practically measured by the difference 
between the dry-bulb and the wet-bulb thermometer. 
A temperature of from 65° to 80° F., with a saturated 
atmosphere, becomes sultry and oppressive. The surplus 
heat cannot be removed by conduction or radiation, and 
the natural effort of the system is to produce evaporation. 
Above 80° F., a saturated air becomes most oppressive. 
Air may be considered dry at 35° F., that is to say, its 
capacity for moisture at that point is low. 
It is because the capacity of air for moisture is so rap- 
idly increased by warming, that, in a climate like ours, it 
is more apt, in rooms, to lose moisture too rapidly than 
it is to be over moist. Air, suddenly heated, appropri- 
ates to itself moisture that should be left for our use. 
We can somewhat prevent the air from appropriating 
too much of the surrounding moisture, if we provide for 
it an additional source of supply by warm water or 
an evaporating-pan. Different states of atmosphere re- 
quire different quantities. Under usual circumstances, 
in rooms having stoves, the evaporation of half a pound 
of water an hour gives a moderately dry and healthy Modes of Heating. 
255 
atmosphere. A sponge moistened from time to time, 
and kept hanging in front of a register, often adds to 
comfort, because it aids partly as a filter to retain dust, 
and is a source of moisture. Vessels of porous clay, 
placed upon the register, have also been used as a 
means of adding moisture. 
10. Another point bearing on modes of heating is 
that made by Hood : — 
“ There are always suspended in the air myriads of par- 
ticles of animal and vegetable matter; but these almost 
unheeded atoms possess a high philosophical importance, 
however they may, generally, be disregarded. Many of these 
particles are easily decomposed by heat, and are then re- 
solved into their various gases, either in their elementary 
or mixed state. Hence many of the methods of producing 
artificial heat are materially affected, as regards their whole- 
someness, by the fact of their being able or not able to 
decompose or chemically alter these floating particles of 
matter. To this cause is mainly attributable the unpleasant 
smell produced by several modes of warming buildings, by 
highly-heated metallic surfaces; and we have already seen 
that the hygrometric and electric condition of the air is also 
altered by the same means. All the different descriptions 
of hot-air stoves are more or less liable to these objections; 
as also the high-pressure system of hot-water apparatus, and 
still more the cockle or hot-air furnaces. Dr. Nott’s stoves, 
and also the Russian and German stoves, are subject to this 
inconvenience; and asphyxia is frequently produced in Rus- 
sia by the use of these stoves. The cockle or hot-air furnace 
is particularly liable to these objections; for not only will it 
act powerfully in decomposing the floating particles of ex- 
traneous matter contained in the air, resolving them into 
sulphureted, phosphureted, and carbureted hydrogen, with 256 
Hygiene. 
various compounds of nitrogen and carbon, but it will like- 
wise decompose a portion of the vapor contained in the air, 
absorbing the oxygen and liberating the hydrogen. 
“ Carbonic oxide is generated by all stoves which are con- 
structed so as to burn with a very slow draught. The carbu- 
reted hydrogen is abundantly produced by the gas-stoves, in 
consequence of a portion of the gas escaping unburned from 
the stove; and this unburned gas, when combined with the 
large quantity of vapor which is produced by the combustion 
of carbureted hydrogen, as already described, renders these 
stoves peculiarly unwholesome. All these causes of deteri- 
oration of the air affect different persons in very different 
degrees; but wherever the causes exist the result will neces- 
sarily be derangement of the animal system, however robust 
the persons may be who are exposed to their influence; but, 
of course, the sensations will be soonest experienced by the 
delicate and the valetudinarian.” 
It is still worse if the cylinder is permitted to become 
red-hot. 
Hot stoves cause a dry or burnt condition of air, 
which it is difficult to describe, but which leads those 
accustomed to wood-fires, or to other forms of heating, 
to speak of the heat as not agreeable. 
11. The dust and dirt connected with the fixing of 
stoves also loads the air with many particles. Care, 
iind an understanding of the evils to be overcome, 
will enable us to guard against many of these disad- 
vantages. As stoves will continue to be the dependency 
of very many homes, it is well that these risks be 
thoroughly appreciated. Stoves, more than modes of 
heating from outside, need good provisions for ventila- 
tion. For as the air being warmed is that of the room, 
it soon becomes foul, and should have some mode of Modes of Heating. 
257 
exit. This should not be by holes around a pipe into 
the bed-room above, which, unless the lower room is 
very open, thus becomes the storehouse of the hot and 
foul air of the lower room. A side flue so near the 
chimney as to be warmed by it may have a movable 
ventilator set in both above and below, and aid much 
in the ventilation. 
12. Where the heating is by hot air, or hot water, 
or steam, brought into pipes running along the walls 
of a room or through radiators, it is to be remembered 
that we are still heating the air of the room, and not 
introducing fresh heated air. It is true that we get 
clear of some of the disadvantages of stoves. The heat 
can be more equally distributed to. different parts of 
the room, and can be more evenly regulated. There is 
no escape of stove gases, and none of the dust connected 
with stoves. The mingling of carbonic oxide with the 
air is not so common, and an overheated or burnt con- 
dition not so often complained of. On the other hand, 
it is heat without any of the possibilities of ventilation 
which are more or less incidental to stoves, stove-pipes, 
and fireplaces. Unless there is provision for natural 
or artificial ventilation, it can be made a form of heat- 
ing in which the contamination of air rapidly takes 
place. For assembly-rooms, schools, and other public 
buildings, it is usually preferred to stoves, because con- 
venient, or because special systems of ventilation are 
associated with it. A fireplace with a small fire in such 
rooms is often wisely used as one of the aids to venti- 
lation, if not for heating. 
Where such pipes are heated by hot air they are 
subject to those changes which occur in heated metal 258 
Hygiene. 
by the alternations of temperature, and may, by their 
joints, let out some of the gases of the fuel or of im- 
perfect combustion. Pipes which are warmed by hot 
water circulating through them can have their heat 
regulated with exactness, and so are free from the ob- 
jections arising from the direct application of heat to 
iron. With water under ordinary atmospheric pressure, 
a mean temperature in the pipes of over ICO0 or 180° 
cannot be secured. Some aid is obtained by increasing 
the velocity of circulation. Greater heat is secured by 
hot water under mechanical pressure, as the radiation of 
the heat to the room becomes more active. 
The use of steam for heating pipes has similar ad- 
vantages, with some increase of effect. For similar 
reasons that water under pressure accomplishes more 
than water at ordinary atmospheric pressure, steam 
with its elasticity and quickness of movement conveys 
heat to the air with greater rapidity. Both for water 
and steam under pressure there must be such construc- 
tion and management as to insure safety. 
13. We next consider those modes of heating in 
which air is introduced, or intended to be introduced, 
into a building or room in a condition pure and warm 
enough for comfortable breathing. The fireplace and 
the stove have been so modified as thus to furnish to 
a room a supply of outside air warmed. 
One plan for doing this is illustrated in the Galton 
grate, where cold air from without is let in around the 
rear of the grate, and, being warmed, becomes diffused 
from the sides of the grate into the room. Another plan 
is, where a stove is surrounded by a metal case, or 
“jacketed,” so that cold-air is let in around the stove, Modes of Heating. 
259 
and being heated ascends above the jacket and is diffused 
in the room. The accompanying diagram illustrates 
the latter method. In each of these cases, the air for 
Jacket-Space 
S 
T 
0 
V 
E 
Jacket-Space 
Floor 
Air. 
FIG, XXIV,—Stove with fresh-air inlet and jacket. 
the draught of the stove or grate is derived from the 
room, while the air that moves about the grate or the 
stove, inside of the jacket, comes from outside, and is 
diffused through the room, as pure air for breathing. 
14. The most common form for the introduction of 
warm air into cold rooms is by the furnace. Intro- 
duced originally only as a mode of heating factories, 260 
Hygiene. 
it came into popular use without a full consideration 
of its relations to heated air and ventilation. 
At first it was, and, to some extent, it still is, merely 
a big stove below a room, instead of in it, and the 
substitution of the heated air of the cellar, or of the 
ground around the cellar, for the air in the upper 
room. Too often this is no improvement, either for heat 
or for ventilation. 
The cellar supply of air is seldom as pure as that 
above ground, and frequently where attempt is made 
to furnish outside air supply, a great deal is still drawn 
from the basement. In the putting in of coal more 
dust is made, and the door is longer open, and so dust 
and coal-gas from this source, as well as from imperfect 
combustion, freely find their way to the rooms above. 
In the effort to make one furnace do for a house, 
pipes are often so arranged as to lose much heat, and 
the smoke-pipe has such a horizontal or circuitous 
course as to diminish draught, and to become over- 
laden with coal-dust and soot. 
15. To meet the first of these objections, it is usual 
to have what is called a cold-air box, so that air from 
out of doors may be let in around the heater, and, hav- 
ing become warmed, pass into the pipes connected with 
registers, and so into the rooms. In such a case the 
draught air for the furnace is that of the cellar. If 
each furnace could be so connected with the outer air, 
and jacketed, that none but the outer air could get to 
it, and so bo warmed as in an air-chamber, and thus 
conveyed, it would accomplish more than is now gen- 
erally secured. 
The cold-air box should in any case be used with Modes of Heating. 
261 
a sieve or wire-gauze to sift the air coming in, and 
should be very tight, so that the cellar or draught air 
cannot get into it, and should be so arranged that the 
air may be distributed about the furnace. In windy 
weather it needs regulation, to secure the proper heating 
of the introduced air. 
The heated air brought into the room should never 
be at a temperature higher than 170°, but is often 
200° F. 
16. The air thus warmed and introduced into the 
room, unless distributed by several registers, comes in 
too much at one point, and has the same or even greater 
disadvantages as to overheated dust and over-thirsti- 
ness for moisture that the stove in the room has. 
An evaporating-pan on the furnace, or one hung in 
the register just where the heated air enters the room, 
is of some service. Attempts have been made, by means 
of a movable top to the register, to have cloths or 
sponges that will also sift out some of the dust and 
moisten the air. It is well to have the registers so 
arranged as to admit of this kind of adjustment. 
Furnaces must be classed as a hazardous method of 
securing pure warm air, and should be subjected to the 
various tests to determine the purity of the introduced 
air. The methods of ventilation adapted to rooms heated 
by furnaces will appear in the general consideration of 
ventilation. 
17. The next method of heating to be noted is that 
of indirect radiation, in which it is attempted to thor- 
oughly prepare the air in every respect before it enters 
rooms or buildings. It is passed over a series of tubes 
or radiators variously heated and arranged so as to 262 
Hygiene. 
secure ample radiating surface outside the rooms, and 
utilize the heat for introduction. It is not necessary 
to give in detail all the various methods adopted. They 
extend to modes of moving fresh air rapidly over these 
radiators, either by high chimneys or fans; to an in- 
definite use of radiating surfaces and the use of felt and 
other wrappings for retaining heat, and of conductors 
and non-conductors, variously applied. 
In some cases, as in the English Houses of Par- 
liament, the air is passed through coarse cloth sieves, 
and is constantly moistened by sprinkling apparatus, 
and then introduced with right temperature and ve- 
locity through perforated floors. It is an attempt to 
secure, for houses, outside air fully prepared for use, 
and has been very successful. Cheap as outdoor air is, 
when thus dealt with, it is quite costly, but valuable. 
It is a general principle, in all methods of indirect 
radiation, that the whole air should be warmed to the 
degree necessary for introduction into rooms, rather 
than that air should be very highly heated in this out- 
side chamber, and then brought to a proper temper- 
ature in this chamber by adding thereto cold air from 
without, so as to make it fit for the rooms. As the 
various modes of conducting indirect radiation, and the 
fixtures required, do not come under household regula- 
tion, we only need to point out the general method of 
adaptation, and the object sought. 
18. In all methods of heating, more attention needs to 
be given to the effects of imperfect or interrupted fire- 
draught, and to the evils of imperfect combustion of the 
fuel used. In fireplaces, and with wood-fires, this so 
declares itself by smoke or by a feeble fire, that it is Modes of Heating. 
263 
soon recognized. But in the various forms of stoves 
and furnaces, the fouled air that gets into rooms from 
this source is very considerable. 
Chimneys should be so built as to shape and caliber, 
as to smoothness of inside surface, as to pipe connec- 
tions in rooms, as to position in walls, and free height 
above roof, as to secure good draught. Often the course 
of the smoke-pipe is too circuitous, or it runs horizon- 
tally so far as much to diminish draught, even where 
the chimney is not defective. The filling up with dust 
and soot is another difficulty, to be remedied by fre- 
quent cleansing. 
Sometimes the draught can be much improved by 
some form of apparatus attached to the top of the 
chimney, usually known as a cowl. Some of these 
caps or cowls are chiefly valuable as keeping out snow 
or rain. The chief object of cowls is to present such 
a surface to currents and winds as to cause an as- 
pirating or suction effect on the air below in the 
chimney. It is well known that a wind blowing across 
a cylindrical tube causes a suction or aspiration. 
These cowls are made so as to adjust themselves to 
the direction of the wind. 
19. There is no source of ill-health so prevalent as 
that dependent upon ill-regulated temperature, and its 
almost necessary accompaniment of impure air. By 
knowing what are the conditions under which the vari- 
ous forms of heating are to be applied, and by testing 
the actual state of the room air, those who are intelli- 
gent and observing will be able to remedy many defects, 
or so appreciate them as to seek skilled advice. 
The great difficulty as to all systems is, that, in order 264 
Hygiene. 
to know whether this plan or that plan is the best, 
all the local complications must be duly considered. 
Even where the system is in general correct, imperfect 
management, or a failure on the part of the person in 
charge to adjust the amount of heat or the plan of 
ventilation to the variation in the number of persons, 
in the state of atmosphere, and in the condition of in- 
mates, may make all the difference between wholesome 
and unwholesome air and a well-regulated temperature. 
20. It is very important that all school-rooms, or 
public assembly-rooms of any kind, have definite and 
well-understood methods of heating and ventilation, 
and that they be placed under skilled management. 
The various forms of pulmonary disease make up a 
very large proportion of the causes of death. They are 
equally the cause of prolonged invalidity. In school 
life, the foundation is laid for very many diseases of 
the respiratory apparatus, that only become fully appar- 
ent in the disabilities of more mature life. Heat is the 
motive power in ventilation, and the greatest complica- 
tions, as to the air we breathe, occur in winter, when 
we are dependent upon it. No physical experiments 
are so important as those that determine the daily 
purity or impurity of the air which is heated and fur- 
nished for indoor life. Pure air is a vital concern in 
education, and, especially in the interest of the rising 
generation, must be furnished. Chapter XY. 
VENTILATION OF HOUSES. 
ALTHOUGH we have already considered air in 
general as related to health, and some of the 
conditions of air in houses as related to artificial heat, 
the modes of securing proper ventilation demand fur- 
ther consideration. Our special need of ventilation in 
houses arises from the fact that the dust, gases, etc., 
incident to house-living, tend to deteriorate the air, 
and that we ourselves, in the process of life, are burning 
out or consuming the oxygen which it contains, as 
well as conveying to it decomposable or organic matter 
and noxious gases. The fires, the gas-jets, and every- 
thing that has breath and life within the house, tend 
to exhaust the air of its life-sustaining properties, while 
the myriads of floating particles load it with organic 
matter more or less unfriendly to vital purity. 
2. The atmosphere provided for us is composed of 
three gases, — oxygen, nitrogen, and carbonic dioxide, 
usually known as carbonic acid. With these the vapor 
of water is always associated. The first two are usu- 
ally called essential elements, hut water and carbonic 
dioxide are so far accessory, that air is never found, 
in nature, absolutely without them. The oxygen, ni- 
trogen, and carbonic acid form a simple mechanical 
mixture which is very perfect, although the same bulk 
of these gases has each a different weight. When thus 
265 266 
Hygiene. 
mixed, the diffusion of gases is so perfect that they 
do not separate, except as they come in contact with 
some substance which will absorb or combine with 
some one of these constituents. 
3. The usual proportion in which these normal com- 
ponents are found is about as follows: Nitrogen, 79; 
oxygen, 20.96; carbonic acid, .04. There are slight 
variations, within a range which cannot be said to 
affect human health. Ozone is oxygen in a peculiar 
state, but as it is not usually found in the air of dwell- 
ings, it need not be treated of here. The active 
principle in the air, in its relation to breathing, is 
oxygen, so that any considerable variation from 20.96 
per centum at once indicates deterioration. If the pro- 
portion comes to be as low as 20.60, the air is to be 
regarded as bad. 
The quantity of nitrogen may become of undue propor- 
tion because of the diminution of the oxygen, but does 
not, by any actual excess, become a danger to life. It 
is only when we come to the artificial conditions of in- 
door life that we find any great change from the normal 
constituency of the atmosphere. This change chiefly 
consists in a decrease of oxygen and an increase of 
carbonic acid. Pure carbonic acid may be present in 
the air to the amount of fifty or more parts in 10,000 
without serious inconvenience, but if the carbonic acid 
present is the result of the burning out of the oxygen 
of the air, as in the process of breathing, the case is far 
different. It then indicates to what degree there has 
been a diminution of the oxygen of the atmosphere 
breathed; and because the amount of organic or de- 
cayable material present in the expired air bears a Ventilation of Houses. 
267 
pretty regular proportion to the amount of carbonic 
acid exhaled, it becomes a measure of this also. 
When the normal amount of 4 in 10,000 is increased 
to 6 or 7, the air is apt to seem close to a person 
entering from the outer air. This will be a little mod- 
ified by the condition of the person, and the tempera- 
ture of the air. A room is stifling when the amount 
is as high as 8 parts to 10,000. 
4. House air that is not habitable generally owes its 
unfitness for breathing purposes to one or all of the 
following conditions. 
(а) The undue deficiency of oxygen and undue in- 
crease of carbonic acid. 
(б) The addition of ammoniacal and other nitrogenous 
products and various gases of imperfect combustion. 
(c) The addition of dusts and various particles of an 
animal, a vegetable, or a mineral nature, some of which 
irritate in their processes of growth and decay, and 
some of which irritate mechanically. 
(d) Such heat and dryness of air as causes it to make 
too great demands upon our bodies for moisture. 
(e) Such heat and saturation with moisture as pre- 
vents the air from readily taking up the perspiration 
or other secretions of our bodies. 
(/) Such sudden changes of air as expose us to 
draughts and to such changes in temperature or in per- 
spiration, as produce colds, irritation, or congestion in 
parts of the system. 
The adjustments and compensations necessary to over- 
come or modify these conditions in our indoor life are 
the chief subjects of consideration when we speak of 
ventilation. 268 
Hygiene. 
5. The first condition is usually due to the presence 
of living beings, of fires or of gas, lamp or candle lights 
in the room, — any and all of which appropriate the 
natural oxygen of the air, and substitute in its place 
carbonic acid. A j>erson, in passing the usual amount 
of 350 or 400 cubic feet of air through the lungs each 
24 hours, appropriates about 18 cubic feet of oxygen 
and exhales a little over 18 cubic feet of carbon. Air 
which has been breathed once has lost about 5 per cent 
of its oxygen, and has gained a little more than 5 per 
cent of carbonic acid. A pound of anthracite coal in 
a common stove consumes 2§ pounds of oxygen, or 
about 32 cubic feet. A candle burning at the rate of 
120 grains of spermaceti an hour, which is the English 
standard of comparison, consumes about one-lialf as 
much oxygen as a man. The combustion of 1 cubic 
foot of coal-gas consumes the oxygen of 10 cubic feet of 
air, and produces 2 cubic feet of carbonic acid. 
6. The second and third conditions are caused by 
various forms of minute particles that are brought into 
the dwelling or separated by the wear of articles therein, 
the various dusts and gases from fires and lights, and 
especially the organic and decayable materials given off 
by the body in breathing, and in its other processes 
of waste and repair. The varying amount of decom- 
posable particles given off by the body in 24 hours 
is estimated at about 300 grains. Of this, the amount 
of animal organic matter from the lungs may be esti- 
mated as 30 to 40 grains per day for each adult. It 
consists of small particles of skin, epithelium, fatty mat- 
ters, and a peculiar fetid, organic vapor, which is the 
cause of the disagreeable odor in close and crowded Ventilation of Houses. 
269 
rooms, and gives rise by its decomposition to products 
detrimental to health. If this air be passed through 
water, the latter soon exhibits all the phenomena of 
putrefactive fermentation. The amount of vapor of 
the skin and lungs together is about 30 ounces per 
diem. These materials vary much in quantity and 
the rapidity of decomposition. When we have many 
persons together, as in an assembly or school room, 
this source of contamination is rapidly multiplied. 
7. The fourth condition,—heat and dryness of the 
air, — is important, because moisture, as well as the heat 
which the thermometer registers, affects our sensation of 
warmth, and has much to do with health conditions. 
In the chapter on Heating we have already presented 
the method by which the body equalizes its moisture 
as well as its temperature. 
8. If the air is hot and dry it makes constant demands 
upon the water of our bodies. About nine ounces, or 
more than half a pint of watery vapor, as an average, is 
given off from the lungs every twenty-four hours. The 
quantity of insensible perspiration is about twice as 
much. When we heat the air we increase its capacity 
for moisture. In its effort to claim this, it seizes upon 
our bodies as one of its sources of supply, and thus 
makes us uncomfortable, unless we can constantly com- 
pensate therefor. 
On the other hand, the saturation of air with moisture 
prevents that free transpiration from ourselves which is 
necessary to comfort. In either case, we are oppressed, 
and must seek a supply of pure fresh air, and of air so 
in motion as to make up for these special conditions. 
9. In providing for the sixth condition, we have, on the 270 
Hygiene. 
one hand, to secure the needed change of air, and on 
the other to so introduce the air as not to cause danger- 
ous draughts. When the external temperature is warm, 
there is little risk in doing this with windows or doors 
wide open, the chief risk being from sitting near small 
holes where the air can rush through in the form of a 
concentrated current like* that from a bellows. But where 
we are dependent upon the heat of the room, it is very 
important that the air does not enter with too much 
draught. Even if it is fresh warmed air, it may he in- 
troduced with such a current as to cause undue heat 
and dryness to those within its range. 
This feeling of draught depends, in part, on the velo- 
city of introduction, and, in part, on other conditions. 
The warmth of the moving air influences the sensation 
of the persons exposed to it. At a temperature of 55° or 
G0°, a rate of IT feet per second (or about 1 mile per 
hour) is not perceived; a rate of 2 and 24 feet per second 
(1.4 and 1.7 miles per hour) is perceptible to many persons; 
3 feet per second (2 miles per hour nearly) is perceptible 
to most; a rate of 34 feet is perceived by all persons; any 
greater speed than this will give the sensation of draught, 
especially if the entering air be of a different tempera- 
ture or moist. If the air be about 70° F., a rather greater 
velocity is not perceived, while if it be still higher (80° or 
90° F.), the movement becomes again more perceptible. 
This is also the case with the temperature below 40° F. 
10. Our power of introducing air into a room without 
draught depends upon the size of the room, the number 
of persons to be supplied with air, the relative temper- 
ature of outside and inner air, and the mode of intro- 
duction. In a small room, it is more difficult to have Ventilation of Houses. 
271 
the air distributed before reaching the person, and so he 
may feel a draught. Where there is a number of persons, 
the air must be introduced more rapidly, unless there 
is adaptation of size of room and modes of introduction 
thereto. We have already noted variations made by 
temperature and moisture. If the air comes in through 
some direct inlet, and nearly all at one or two points, 
more draught is likely to occur. Smallness of opening 
may give direction to the current, as where a hole in a 
pane of glass directs a current upon some exposed part 
of a person near by, and causes a draught which a 
wide-open window would not. As a rule, we are not so 
likely to have draughts when the air is introduced at 
various points in small quantities, instead of at two or 
three points in large quantities. 
We also do much to prevent the sensation of draught 
if we introduce it above the heads of persons occupying 
the room, and in such wise as to secure for it a slight 
ascent. Thus, if the lower sash be raised and a tight- 
fitting strip of board be placed under it, the only inlet 
will be near the middle of the window, between the 
lower and the upper sash. The upper part of the lower 
sash serves to give to the air, as it enters and gains a 
little heat, a slight upward motion. The direct current 
of the air is intercepted. It is also true that if a wire 
gauze is put in under a sash, or at the upper part, it 
cuts the air so as to diminish the draught. 
11. The amount or air-space needed by each individual 
depends primarily upon the amount of oxygen that is 
being burnt up or removed from the air of the room. 
Our first data are derived from the amount of air 
consumed or deteriorated by each person. If every 272 
Hygiene. 
breath took out only a certain amount of air and its 
oxygen, and the expiration or outbreathing of the air 
from the lungs did not return to the room, the problem 
would be a simple one, for new and pure air would 
take the place of the air extracted by breathing. But 
a cubic foot of air, as it comes from the lungs in ordinary 
respiration, has lost most of its oxygen, and contains, 
instead, upwards of seventy cubic inches of carbonic 
acid, besides organic matter and fouled watery vapor. 
This air has not only been devitalized, but infused with 
injurious particles. 
The need of air-space or ventilation also depends upon 
shape of room, height of ceiling, floor-space, etc. 
12. With all these facts in view, those who have most 
carefully considered them, and have tested by experi- 
ment also, claim that in a room ordinarily tight 2,000 
cubic feet of air must be admitted each hour for each 
person in it. This is based upon the conclusion that, 
to preserve the standard of purity, about 650 feet of air 
is actually needed each hour for each person. But as 
practically we cannot change the entire air of a room 
oftener than three times an hour without draught, we 
must introduce three times the amount actually used up. 
The amount of cubic space required for each person 
has been stated as from 250 to 300 feet for dwellings, 
school-rooms, etc., while for tenements, hospitals, etc., it 
should be much more. As school-rooms are not occu- 
pied all the time, and give opportunity for air-flushing 
during and after school, from 25 to 30 cubic feet of 
air per minute for each person will answer. 
As height of ceiling over twelve feet is not counted, 
this would give to each person in a room, or to each Ventilation of Houses. 
273 
scholar in a school, a floor-space of about four feet by 
five, or five feet by five. 
13. It is well to consider all the various theoretic 
needs and modifications, because they help us to attain 
to accuracy. What is called experience needs to be 
tested by scientific facts, just as scientific facts need to 
be tested by experience. In this case, with the fact that 
there are so many modifications, and the additional fact 
that no room is dependent upon any one inlet, since 
windows, crevices, and even bricks admit much air, 
the statement of test most relied upon is that of 
Parkes and De Chaumont, which is, that the amount 
of air required for any occupied room is the amount 
needed to keep the room free from any perceptible 
odor to a person entering it from the outer air, and 
to keep the percentage of carbonic acid (carbon di- 
oxide) as near as possible to the normal rates of four 
parts in 10,000, and never beyond seven parts in 10,000. 
14. The sensation of uneasiness produced by breath- 
ing impure air is an indication of the injurious effects 
that result from it, which is too often neglected. 
When the air is not sufficiently pure to effect the 
complete decarbonization of the blood, we have already 
seen that the result is the circulation of venous blood 
through the brain; the respiration then becomes im- 
peded, and the nervous system deranged; the extent 
of these effects, of course, varying with the amount 
of the exciting cause, and with the peculiar constitu- 
tions of the individuals exposed to their influence. 
I)r. Harwood remarks on this subject, “ The want of 
wholesome air, however, does not manifest itself on the 
system so unequivocally, or imperatively; no urgent 274 
Hygiene. 
sensation being produced, like that of hunger, and 
hence the greater danger of mistaking its indications. 
The effects of its absence are only slowly and insidi- 
ously produced; and thus, too frequently, are over- 
looked until the constitution is generally impaired, 
and the body equally enfeebled.” 
15. Ventilation is generally spoken of as either natural 
or artificial. It is called natural when there are no 
special appliances for the admission or removal of air. 
It depends upon the difference in the specific gravities 
of warm or cold air. Of this character is that ventila- 
tion which takes place through the porous walls of 
buildings, through cracks and crevices, and through 
windows and doors which may be opened and closed. 
Where there is a chimney with opening into the room 
it also is spoken of as a natural mode of ventilation, 
although its capacity in this respect will vary much 
with the temperature of the column of air it contains. 
The incidental and by no means unimportant venti- 
lation afforded by stoves and by grates, or fireplace 
fires, are also generally included in natural ventilation, 
since they are not specially arranged for that purpose. 
They not only are fed by the air drawn to them, 
which thus makes a vacuum to be filled by incoming 
air, but they have much to do with the interchange of 
currents in the room. Besides the air thus drawn 
in for combustion, in fireplaces, much air escapes 
above the fire, and in many stoves upper openings 
draw out much of the air of the room. Stoves with 
good draught thus receive air from the room, and by 
directly connecting with the chimney serve as venti- 
lators. Ventilation of Rouses. 
275 
It is to be borne in mind, that rooms which have 
their heating apparatus within them are much more 
likely to be ventilated in this way than those into which 
heated air is introduced. For rooms heated in the 
latter way do not make draught of air to the same 
extent as does a heating center within the room, and 
do not, like the stove or fireplace, provide an exit for 
air. 
16. Where natural ventilation alone is depended upon, 
the thermometer, and the sensations of individuals, are 
the chief guide, as to the purity and comfort of the 
air. Too often, however, the inmates become used even 
to foul air, and it is wise to test it by the sensations 
of those coming in from out-of-doors. 
In this method of ventilation the chief question, so 
far as the entrance of air is concerned, is how to 
prevent draught. We have already alluded to some 
of the methods in use. Various other methods are 
devised, which may be divided into three classes, viz. 
those which by means of small holes, or gauze, or 
screens, or holes as in wainscoting, seek to let in the 
air through many small apertures, instead of a single 
one; those which introduce it through double sashes, 
or bent tubes, or elbows, so that it shall not come in by 
direct current, and shall, perhaps, get a little warmed 
in the entrance, and those which, as in the so-called 
Tobin system, or by perforated brick and valves, in- 
troduce it above the heads of persons so that it shall 
first mingle with the upper air of the room. All of 
these admit of some method by which the air can be 
shut off if the room is too cool. 
17. In all the methods of natural ventilation, it is 276 
Hygiene. 
generally assumed that there will be such interchange 
of currents that foul air will get out of the room by 
natural methods. Occasionally, this is aided by placing 
some form of valve in the side of a chimney, or some 
form of ventilator near the ceiling, with the idea 
that the foul air will ascend with the heat, and find 
readier exit there. Such openings often let out smoke 
or become wholly or partly shut by soot. While with 
few persons in a room, and good housekeeping and 
good judgment on the part of the occupants, such 
methods of ventilation may answer for a time, they 
are evidently not adapted to rooms where there are 
many persons, or where the heat is derived from out- 
side sources. It is to be borne in mind that foul air 
is heavier than pure air at the same temperature, and 
also- that warm air being rarefied does not, with each 
breath, give so much oxygen to the lungs as cold air. 
18. Artificial ventilation is where some mechanical 
means are used either for the admission or removal 
of air or for both. 
It is also not uncommon to have artificial methods 
for the ingress of air with no artificial methods for its 
egress, or to have artificial methods of egress, trusting 
to natural methods for its introduction. 
When fresh air is introduced into the room by some 
mechanical force, it is usually spoken of as the plenum 
method, as when, for instance, a bellows or fan intro- 
duces cold or warm, fresh air into the room. 
When, on the other hand, air is drawn out of a room 
by some mechanical force, it is known as the exhaust, 
suction, or vacuum method. 
In some buildings both are used; in others, one or Ventilation of Houses. 
277 
the other only is used, it being claimed that if you 
drive in air, the impure air will find its way out, or if 
you pull out air, other air will find its way in. In 
either or all of these plans, we need to bear in 
mind that the law of diffusion of air and of gases is 
not dependent upon the specific gravity or tempera- 
ture, although these effect some modification. All gases 
tend to diffuse horizontally. 
Air laden with organic particles, even if warm, tends 
to cool as it reaches walls, and to flow down their 
surfaces and settle, or find exit near the floor. It is 
not safe to form all our plans upon the basis that the 
air as it comes from the lungs is warm, or that car- 
bonic acid is heavier than pure' air, or that heated air 
ascends and cool air falls. In practice, and in the 
interchange of currents amid numbers of people, there 
are variations from this rule, which need both the 
tests and judgment of experts and the experience of 
close observers. 
19. The reasons which in some cases decide for in- 
troducing the fresh warm air at the top of the room, 
and in other cases at the bottom, are well presented 
by two good authorities. Prof. Huxley states the first 
view thus: — 
“ If there is little or no interference with outside currents, 
the air within the building may readily be made to move 
in a body from above downward, and the rapidity of its 
movement can be easily regulated. It may be objected to 
this downward movement, that the natural tendency of 
impurities is upward with the course of the warmer air, 
and that, by being made to take a downward direction, 
they are brought back again to be reinhaled. If it were 278 
Hygiene. 
true that the impurities as such immediately rose to the 
ceiling and escaped from the apartment, the objection would 
hold; hut this is not the case. On the contrary, it is known 
that the carbonic acid and other gaseous impurities are 
equally diffused, and the weight of the organic substances 
and other suspended matters leads to the inference that 
they would gravitate toward the floor, particularly when 
rising currents of warm air are excluded, as they should be, 
by introducing it at the top of the room. In no other way 
can so steady and equable a movement be obtained as by 
introducing the warm air at the top, and removing it below; 
and, apart from any theoretical considerations, it is found to 
yield excellent practical results.” 
20. This view, however, while in the main correct, 
does not decide that, with proper adjustment of inside 
arrangements and the introduction of warmed air, it 
may not be better, in other cases, to introduce the air 
from below. D. B. Dick speaks of another method, 
thus: — 
“ Before we can arrive at a definite conclusion, we must 
consider what becomes of the cold air that will find its way 
in, in spite of our efforts to keep it out. Little streams of 
it will flow in under the doors, trickle down the face of the 
outside walls, and especially from the windows, also from 
all the chinks that ought to be air-tight, but are not. But, 
wherever they come from, they will all settle in a layer on 
the floor. The thermometer proves this, while our cold feet 
corroborate its evidence. Even the cat shows its knowledge 
of the fact by getting up on the chair to get out of it, or 
deserting her soft rug on the floor to sleep on the bare top 
of the kitchen table. 
“ The warm air being admitted at the floor will warm Ventilation of Mouses. 
279 
some of the cold air there, losing some of its own heat in 
doing so; then in its ascent to the ceiling it will carry with 
it the vitiated air and the watery vapor, with its organic 
impurities, and if the outlet is at the ceiling, it will sweep 
them both out of the room, without giving them a chance 
to cool and fall down again among the pure air. Although 
it is desirable that there should be a number of separate 
inlets, it is better to have only one outlet, because if the suc- 
tion should be greater in one than the other it might draw 
against it, and then the flow of air would be from one outlet 
to the other, instead of from the inlets to the outlets.” 
21. As in many other cases, it is easy to announce 
the principle, and easy, afterward, for the architect and 
the sanitary engineer to determine in any given house 
or room the method best adapted. But to give a rule 
or dicta, inflexible and applicable to all cases, is not so 
easy. So much depends on variations, most of which 
are controllable, some of which are difficult of control, 
that we must not too readily conclude that we can 
apply just the same method in every case. 
Although the introduction of the fresh air above has 
often been successfully adopted, yet such results as 
that of the Grand Opera House at Vienna, and the 
Fifth Avenue Presbyterian Church of New York, show 
how the method of introduction of warmed pure air 
from below is successful. It is also admitted to be 
more economical. More depends upon the locality and 
number of the entering points than upon proximity to 
floor or ceiling. 
For the removal of foul air, it is now generally believed 
that openings near the floor are more useful than those 
at the ceiling, although in large assembly-rooms both are 
desirable. Hygiene. 
280 
22. The whole subject has been well stated by Dr. 
J. S. Billings, in his recent work on Ventilation and 
Heating, from which we abbreviate the following out- 
line : — 
“First. The register must be in such a position, and of 
such a size, that the requisite amount of air can be introduced 
through it without causing currents of air of such velocity 
as will cause discomfort to the occupants of the room. The 
only difficulty in this respect occurs in rooms occupied by 
a number of persons, such as assembly and school rooms, 
churches, theaters, hospitals, etc. Under such circumstances, 
it is sometimes very difficult to so locate the fresh-air 
registers that the currents therefrom will not be unpleasantly 
perceptible if they are rapid, and it then becomes neces- 
sary to make these registers of such an area that the velocity 
of the inflowing air need not exceed one and a half feet per 
second to secure the introduction of an amount sufficient 
for both warming and ventilation. When the registers 
are so situated that the currents from them will produce 
no discomfort, they may be made smaller. For example, 
if it be determined to introduce the fresh air directly 
through a perforated floor in an assembly-room, the total 
area of openings should be at least one hundred square 
inches for each occupant, while the area of register open- 
ings need not be more than forty square inches for each 
occupant, if they are placed near the ceiling. 
“ Second. Taking it for granted that the fresh air is to 
be warmed in cold weather before it is brought into the 
room, its registers must not be placed below the foul-air 
registers, unless the former are scattered near the floor 
of the room. The reason for this is, that direct currents 
between the inflow and outflow registers are easily estab- 
lished when the latter are above the former, and in such Ventilation of Rouses. 
281 
case little change is effected in the great mass of the air in 
the room. 
“ Third. Flues of proper size cannot usually be placed 
in thin walls, such as ordinary interior partitions. A flue 
measuring less than five inches in its smallest diameter is 
of little use. Fortunately, in ordinary dwelling-houses, 
where this difficulty of thin partition walls is greatest, the 
precise location of fresh-air and foul-air flues is of minor 
importance, so long as the precaution advised in the pre- 
ceding section he observed. 
“ Fourth. Fresh-air registers should not be placed in a 
floor so as to be flush with its surface, because dust and dirt 
will fall into the flues and be returned, to a certain extent, 
in the column of ascending air. Such registers are also a 
fruitful source of loss of small articles. It is always pos- 
sible to continue the flue upward into a step or seat, and 
then place the register in the side of this. 
“ There is less objection to placing foul-air registers in the 
floor; but even this should be avoided, unless the open- 
ings are covered by some article of furniture, as, for instance, 
in a hospital ward, where a good position for the foul-air 
registers is in the floor beneath each bed; and even then 
the register should not be flush with the floor, but rise an 
inch or two above its surface. 
23. “ Fifth. In dwelling-houses and buildings of moderate 
size, it is economical to centralize the heating apparatus 
as much as possible, keeping the fresh-air flues in inner 
walls; but it is not easy by this method to secure suffi- 
cient warmth in the vicinity of windows, especially on the 
side most exposed to the winter winds. 
“On the other hand, hot-air flues should not be placed 
in outer walls, unless these are thick and substantial, and 
even then it will be good economy to make the flue of terra- 
cotta or galvanized iron, so set as to leave an air-space of 282 
Hygiene. 
an inch or two on the other side. For rooms on the floor 
immediately above the radiators, it is not necessary to place 
flues in the walls in order to bring the registers under or 
near the windows, which is their best place, so far as heating 
is concerned. Foul-air flues should not he placed in outer 
walls, unless they are to be carried downward and to have 
some means of aspiration connected with them. 
“ Sixth. General Morin, and the majority of modern French 
engineers, advise that the place of introduction of fresh air 
shall be near the ceiling, in order to avoid unpleasant 
currents, while the discharge openings, on the contrary, 
should be near the floor. The introduction of warm air 
near the ceiling, in order to prevent disagreeable currents, 
is not absolutely essential, for such currents can be avoided, 
as above explained, by making the registers of proper size; 
and to secure comfort in cold weather, it is necessary, on 
this plan, that the air shall be introduced at a temperature 
several degrees higher than is required if it he admitted at 
a lower level. 
“ The proper position of the foul-air registers depends on 
the purpose of the room and on the season. During cold 
weather, in the majority of cases, they should be near the 
level of the floor, to secure a satisfactory distribution of 
the air with the least expense. In large assembly-halls, 
however, and especially where it is desired to provide for 
respiration, air as pure as possible, instead of foul-air diluted 
to a certain standard, the discharge-openings should be above. 
“ Seventh. In order to secure a thorough distribution of 
the incoming air, it is usually recommended that the dis- 
charge-openings should be in the side of the room opposite 
to that in which the fresh-air openings are placed, and as 
far as possible from them. 
“ In all dwelling-houses, however, and in rooms not hav- 
ing windows on opposite sides nor containing a sufficient Ventilation of Houses. 
283 
number of occupants to exercise any special influence on 
the temperature, good ventilation will be secured by placing 
the fresh warm-air openings on an inner wall, and the dis- 
charge-openings in the same wall at the same or a lower 
level. This is the arrangement in most dwellings heated 
by indirect radiation, the fresh-air register being in the 
side of the chimney near the floor, and the foul-air passing 
out through perforated fireboards on the same level a few 
feet away. The result is the establishment of a circulation 
from the fresh-air opening upward and along the ceiling 
to the outer walls and windows, thence down the wall to the 
floor, and along the floor to the discharge. 
“ But when we come to deal with rooms having a large 
floor area in proportion to the height, and containing fifty 
or more persons, whose heat production is a factor that 
must be taken into consideration, there is some danger by 
this method that there will be an unsatisfactory distribu- 
tion of the fresh air when the temperature of the external 
air is not below 50° F.” 
24. Where the method is that form of indirect heat- 
ing in which a room is kept warm by radiators or pipes 
which receive their heat from apparatus outside the 
rooms which does not introduce any new air with the 
heat, we are always to bear in mind that, although 
the heating does not consume the oxygen of the air 
in the room, it does not provide any means of escape for 
foul air. So, practically, such rooms, if occupied by many 
persons, greatly need good artificial arrangements for 
ventilation. 
Where some form of flue is relied upon for ventilation, 
the following points are to be borne in mind. No flue 
can be considered complete unless it has a caliber of eight 284 
Hygiene. 
inches in diameter, is smooth internally, and unless, by 
some means, a pretty uniform temperature up to about 
65° can be secured in it. Ventilating-pipes connected 
with it should also be smooth, and angles should be 
avoided as far as possible. Not enough allowance is 
made for the effect of angles on friction, and for the ad- 
hesion of air to surfaces. Many holes that are called 
ventilators, the anenometer and other methods of test 
show to be very deficient in draught, and so of little ser- 
vice. The draught is sometimes aided by cowls or other 
fixtures attached to the top of the chimney or duct, vary- 
ing with the wind, and aiding the outward current. 
25. The testing of the purity of the air is a matter of 
importance, and yet so much a chemical and biological 
investigation as to be at the command of those unskilled 
in methods, to only a small extent. The test afforded by 
the sensations of those coming into rooms out of pure 
air is of considerable value, as the unblunted senses are 
themselves instruments of test. 
What is known as the Angus Smith method is quite 
available. It is based on the fact that the amount of 
carbonic acid present in air is an approximate test 
of its purity or impurity, and that we are able to get an 
ocular sign of this by the use of lime-water. 
Dr. Lincoln, of Boston, lias found the . following test 
available. A series of bottles of known size are chosen, 
graded from large to small, and fitted in a wooden frame. 
The whole apparatus is carried to the room to be tested. 
The bottles have been previously filled with water, and 
when inverted the air fills them at once. They are 
stoppered and carried to the laboratory, where a given 
amount (say one-half ounce) of lime-water is introduced Ventilation of Houses. 
285 
into each, and also a few drops of a solution of phenolph- 
thalein, which gives a rose color to the lime-water. By 
long shaking of the bottles, the carbonic acid present is 
neutralized, and the color fades. The largest bottle that 
shows a complete change affords a comparison by which 
we may reckon the amount of carbonic acid gas present. 
What is known as the Wolpert test is a convenient 
form of apparatus in which, by means of a graduated 
glass tube containing some lime-water, and another glass 
tube with a rubber bulb, the air of the room is squeezed 
into the lime-water, and the number of compressions with 
the hand necessary to cloud the lime-water, quite accu- 
rately determines the amount of carbonic acid present. 
26. In connection with the subject of heating and ven- 
tilation the mode of lighting needs some consideration. 
The effect of sunlight is conservative of health, although 
it may so be reflected in rooms as to cause excess of heat, 
to which ventilation must be adjusted. The electric 
light has the advantage over all other artificial lights, 
in that it does not consume the oxygen from the at- 
mosphere or add to it carbonic acid gas. It is also 
free of dust and of other gases which are apt to be 
mingled with other forms of lighting. 
All other forms of light used are damaging to the 
purity of air, chiefly as they exhaust oxygen and add 
carbon dioxide. But they vary considerably as to the 
amount of smoke, imperfect combustion, and of dust 
and gases. So much heat is evolved from a common 
kerosene lamp, for instance, that the currents it causes 
are also to be considered. Some of the lamps which are 
arranged for use without chimneys also contaminate the 
air by imperfect combustion. 286 
Hygiene. 
27. In the use of gas, as a matter of self-protection, 
consumers should occasionally test the quality of the gas. 
Gas employees, in certain parts of their work, often 
suffer from catarrh, bronchitis, and phthisis. This is in 
part due to the ammonia, carbonic acid, sulphureted 
hydrogen, and other gases evolved. The purifiers, con- 
densers, and washers seek to remove these, and do it 
quite effectually when the apparatus is in good order 
and skillfully used. Gas cannot be used in a conserva- 
tory unless the products of combustion are fully removed. 
It is impossible to remove the sulphur entirely from 
gas. The English law prescribes that there shall be 
no sulphureted hydrogen in the gas as delivered, and 
that other forms of sulphur combination shall not ex- 
ceed twenty-five grains per one hundred cubic feet. 
28. Lights have, by their heat, been largely utilized 
for making a draught that will carry foul air out of 
rooms. To this end, chandeliers often have air-ducts 
above them communicating with the roof. While these 
are not quite so effective as they seem to be, and do 
not generally make a current that reaches to the sides 
and corners of the room, they nevertheless aid some- 
what in an upward draught. There are now instru- 
ments of precision by which it is possible to determine 
where and how to fix and locate foul air-ducts, as 
also to determine the velocity of movement of the air 
in them. 
29. Gas, as made by the iron process, consists chiefly 
of hydrogen .40 to .50 parts, marsh-gas .35 to .45, car- 
bonic oxide .045 to .075, olefiant gas and other hydro- 
carbons .04 to .08, and usually very small amounts of 
carbonic acid and air. Ventilation of Houses. 
287 
Gas made from petroleum contains no sulphur or 
ammonia. 
Water-gas, as it is called, is made by passing steam 
over incandescent red-hot carbon, the product being 
a mixture of hydrogen and carbonic oxide. This non- 
luminous gas is then made luminant by the com- 
bination with it of gas from petroleum, naphtha, or 
cannel-coal. It contains, as a rule, about 50 per cent 
of hydrogen, 40 per cent of carbonic oxide, and 10 per 
cent of petroleum or naphtha gas. 
It is now claimed by many companies that the car- 
bonic oxide, which is so injurious, is reduced so that it 
is equal in purity to the gas produced by other pro- 
cesses. There is need, we believe, of a constant watch- 
fulness among consumers, to have the quality of the 
gas furnished tested from time to time. 
30. Escape of gas by reason of imperfect gas-fixtures 
is to be carefully guarded against. The Brooklyn report 
of 1883 shows that many lose their lives, or are par- 
tially suffocated thereby. Many more suffer a general 
deterioration of health. 
Various forms of gas-burners are now in the market, 
some of which, no doubt, save the consumption of gas. 
They are all to be tested as to whether they interfere 
with combustion. 
Electricity will no doubt ere long be made available 
to the student and to homes for lighting purposes. In 
the great advantage that it does not consume the oxy- 
gen of the air, and has no deleterious gases, it commends 
itself as one of the aids to securing greater purity of 
air. It needs to be tested more fully as to the effect 
of the light on the eyes, and as to what shading is 288 
Hygiene. 
needed. It is well adapted for large assembly-rooms, 
and will aid much in preventing that stifling sensation 
too often experienced where large evening audiences are 
assembled. 
It is thus apparent that the whole subject of arti- 
ficial lighting needs to be recognized as related to the 
contamination of air or the reduction of its oxygen, as 
also to some extent as affecting modes of heating. Chapter XVT. 
THE SCHOOL AND ITS APPOINTMENTS. 
WHILE it is recognized that it is not always possi- 
ble to secure the very best sites or buildings for 
schools, it is always desirable to have a perfect ideal 
as a standard of comparison, and to secure the nearest 
approach thereto. 
First of all, it is important to secure ample grounds 
around the building. This is not only desirable for play 
and recreation space, but because buildings closely ad- 
joining, by interference with light and ventilation, and 
by noise, smoke, or other inconvenience, detract from the 
completeness of the building for its purpose. The front- 
age of the building depends somewhat on locality and 
direction of winds. Effort should be made so to arrange 
it as to give to each room some sunlight on pleasant 
days. As a rule this is best accomplished by having 
the corners of the building in the direction of the four 
cardinal points. 
2. The choice and preparation of the ground for the 
building must also have special reference to the secur- 
ing of a dry, well-drained area. The water-level in the 
soil should never be higher than seven feet from the 
surface. Ground that is compact, like clay, must be so 
thoroughly underdrained as to give a cellar that will 
be dry, and a playground from which water will quickly 
disappear. The building should be so provided with 
289 290 
Hygiene. 
rain-leaders as that the water from the roof will not fall 
upon the lot, but be carried off to the street or other con- 
venient place. It is usually best to have the cellar or 
basement partly above the ground level, so that it may 
have windows which will not need to be in part below 
the surface. 
Where the entire structure is to be of stone or brick, 
it is best to have a damp course, just above the ground 
level, either of slate or asphalt, so that there may be no 
conveyance of any possible dampness to the upper walls. 
With a view to proper aeration or equability of tempera- 
ture, wooden school-houses should be inlaid with brick. 
3. Entries and stairs must always be wide. The stairs 
should never be spiral, but have platforms or landings 
instead of long flights. The steps should be of good 
width and easy rise. The best width is generally not 
less than 12 or more than 18 inches, and the rise not less 
than 4 or more than G inches. The French rule is as 
follows: “ As, on the average, human beings move hori- 
zontally 2 feet in a stride, and as the labor of rising ver- 
tically is twice that of moving horizontally, the width of 
the tread added to tAvice the height of the rise should be 
equal to 2 feet. Thus, if the rise be 6 inches, the tread 
should be 12 inches. For children, the width of the 
tread should be a little less. Doors must al\Arays open 
outAvard. Double stairs or fire-escapes are often needed 
as a precaution. School-rooms should never be higher 
than the second story above the basement.” 
Ceilings less than ten feet in height and 0ATer twelve 
are not desirable. A greater height than tAATelve feet 
adds to the number of stair-steps and gives no valuable 
aid to ventilation. The School and its Appointments. 
291 
The first great effort should be to keep dampness and 
dust out of school-rooms. To this end, all over-clothing 
must be well provided for in rooms outside of the school- 
rooms. The narrow stall system, in which each pupil 
may leave all outer garments, rubber-shoes, umbrellas, etc., 
is desirable, and not expensive, if space is well utilized. 
4. It is seldom advisable to have more than 50 schol- 
ars in one room. With a floor-space of 25 feet for each 
scholar, this would give 1,250 feet of floor. A room 25 by 
50 or 30 by 40 is better than a square. For class-rooms 
alternately occupied, a floor-space of 15 feet will answer. 
It is very important that the floor be of such material, 
and so oiled or polished, and so joined, as that dust shall 
not lodge in crevices. For the same reason, all beaded 
mouldings on doors or windows are to be avoided. 
Every particle of dust kept out of a school-room, and 
every crevice avoided, is so much gain for the air of the 
room. The greatest difficulty as to desks or seats fas- 
tened to the floor is that they serve as catching-places 
for organic particles. In all well-ordered schools, at the 
spring and fall room-cleaning, they are unscrewed and 
removed so as to admit of thorough cleansing of floors. 
The desks and all shelves need thorough scrubbing. As 
a rule, wainscoting for school-rooms is better than the 
base-board, if only the seasoning and joining are such 
as to present one even surface, easily kept cleansed and 
dusted. Above this, whitewashed walls are best for crowded 
schools, since a coat of whitewash each month will do 
much for the purity of the air. Where other walls are 
had, they should be of the hardest and smoothest finish. 
5. Where, for any reason, light from the sides or rear 
cannot be commanded, light from above is much better 292 
Hygiene. 
than light from below the level of the pupil’s head. Light 
from above is shaded by the eyebrows, eyelids, and eye- 
lashes, and often by head-coverings, so that we can more 
easily adjust ourselves to the excess. Light from below, 
especially from white and polished surfaces, will soon 
tire the vision. Single, quarter-round cornices should take 
the place of any network adornments. Rounded corners 
are now preferred wherever they can be made. 
White walls are not so favorable to many eyes as light 
blue. Light in which the blue element is in excess, 
although not to the exclusion of all others, is b}r most 
persons felt to be soothing and grateful. Gray and light 
green are also good colors. After the discovery by New- 
ton of the compound character of light, it was soon 
found that the harmonious and pleasing combinations 
were those in which the colors are complementary, that is, 
in which they would make up white light if blended 
together. 
The window-space in school-rooms should not be less 
than one-fifth of the floor-space. The panes of glass 
should be large, so that series of cross-bars will not in- 
tercept the light. As it should not come from below the 
level of the pupil, while sitting, they should be not less 
than four feet from the floor. The windows both for 
light and ventilation should extend nearly to the ceiling. 
Light from the rear is much better than from the front. 
Light from the left side is to be preferred to light from 
the right, since we read and write from left to right, 
and the arm and hand do not obstruct it. If win- 
dow-shades are used they should be of colors similar 
to the wall, and should only be used to keep out 
sunlight or very excessive light. There should be a The School and its Appointments. 
293 
passage-way between the windows and the desk, and no 
desk should be so far from a window, or so situated as 
to other occupied desks, as to much diminish or intercept 
the light. 
There should be transom or tilting windows over the 
doors. 
6. The location of blackboards in the room is im- 
portant. These should be so placed that the pupil will 
not have to face the light, but receive it from the left 
side or the rear. Great care should be taken that black- 
boards are in excellent order, so that marks upon them 
can be distinctly seen. The scholar should have no 
embarrassment in work of this kind. Letters or figures 
on boards, when well made and full two inches in height, 
cannot be seen over thirty feet. 
7. Seats should be single if possible, and desks should 
be adjusted to the size of the scholars. The front of the 
desk should be perpendicular to the edge of the seat, 
and the position will be a convenient one if the desk 
is so arranged as to admit of partial folding, or change 
of angle. In writing, the paper should be raised to an 
angle of 20°; for reading, it is better raised to an angle 
of 40° ; but if not adjustable, 30° will answer. The rela- 
tion of the seat to the desk should be such that the 
book may be from 12 to 16 inches from the eyes when 
the scholar sits erect. The shelf beneath the desk 
should be movable so that it can be taken out, at the 
direction of the teacher for examination. The socket 
for the inkstand should be open, so that any dust may 
fall through. 
A good rule as to the relative height of seats and 
desks is, that the desks should be of such a height 294 
Hygiene. 
that the elbows may rest upon them when the body 
is erect without any displacement of the shoulders. It 
is not to be forgotten that the physical system is pliable 
during the period of school life. Bones and cartilages, 
as well as softer tissue, yield to continued pressure, 
and become permanently set in a wrong way. Many 
injuries to the spinal column, to the chest, to the eyes, 
occur in school life. The heating and ventilation of 
rooms are treated in a separate chapter, and serve as 
directions for schools. 
8. No perfection of a school-room will take the place 
of excellent janitorship, which means thorough house- 
keeping. The arguments for sweeping and dusting 
and airing occupied rooms in the house each day are 
multiplied more than tenfold when we come to deal 
with a school. Scrubbing of floors, dry and sometimes 
wet rubbing of paint and of walls, washing of furniture, 
and all the details of the very best room-keeping, must 
be sedulously attended to. It is not only a part of 
health and comfort, but of the true education. It aids 
much in the training of the children to correct habits 
as well as in the securing of better health. Thorough 
airing should always take place immediately after the 
dismissal of the scholars. 
9. Spitting on the floor should always be an offence, 
and all the more since we have come to know that 
the dried sputa of whooping-cough, diphtheria, and of 
other diseases can impart the contagion. A single 
spittoon in each room should be provided for an abso- 
lute necessity. There should be a waste-basket in each 
school-room, so that nothing may be thrown upon 
the floor. These are not mere niceties, but have to The School and its Appointments. 
295 
do with discipline and health. Each school needs to 
be provided with wash-basins, soap, and towels. Clean 
hands, a clean face, and a pocket-comb help on the true 
education: 
The school life should not prove any risk to health, 
but should have the preservation or improvement of 
health as one of its educational designs. Calisthenics 
and gymnastics, as already referred to, aid much in 
securing pure air and right development. 
10. It is recognized that many nervous diseases have 
their origin in school-life. A good authority has said 
that in its ultimate analysis education is a training 
of the nervous system. Perfect health and rhythm of 
the nervous system has very much to do with vigor, 
self-control, self-reliance, right habits, and success. It 
is a mastery that is to be studied and trained for. 
Overwork, spasmodic work, cramming spells, mental 
pressure, without physical exercise and recreation, are 
the causes of debility, headache, irritability, sleepless- 
ness, dyspepsia, and nervousness in all its protean 
forms. Slight attacks of any spasmodic disease, by the 
law of imitation, are apt to incline others of mobile 
temperament to similar disturbance of self-control. 
Such symptoms must very early attract the attention 
of teachers during the period of school life. We should 
never wait for spasm or lesser irregularities of nervous 
and muscular action, or for that general want of tone 
which too often proclaims an impending break-down 
or wreck of that which is the most intricate and sensi- 
tive of all vital structure. Nay, we should see to it 
that there is such well-planned and well-executed edu- 
cation of all that relates to bodily development as 296 
Hygiene. 
shall preclude the possibility of the mind being edu- 
cated at the expense of the body. There is a hygiene 
of the mental as well as of the physical. They are so 
interwoven, that they train with poor judgment and 
worthless hands who seek to guide or handle the 
one without the other. 
11. While the diseases of schools are not peculiar to 
school life, yet some of the communicable diseases are 
so fostered by or spread from our schools as to need 
special caution. 
The impure breath and the soiled skin are the two 
first great sources of a minor class of transferable dis- 
eases. Thus it is not uncommon for parasitic diseases, 
such as those of the scalp or some form of skin irritation, 
to be conveyed by those who are not cleanly in their 
habits, or who have contracted them from uncleanly 
sources. 
Even common sore throats are sometimes communi- 
cable, and unclean mouths and foul breaths should be 
prevented by the free use of water for rinsing, and by 
cautions in special cases. The teacher by general 
statements as to the relation of foul breath to bad air 
and disease can often inculcate the spirit of cleanliness. 
Inflamed or sore eyes we have occasion to notice 
elsewhere. But it cannot be too plainly impressed that 
sore-eyed children should not attend school unless 
some physician lias vouched for the mild and non-com- 
municable character of the malady. 
12. Among the usual contagious diseases, measles, 
whooping-cough, and mumps are very frequently aided 
into epidemic prevalence by the schools. As a rule it 
is generally not considered necessary entirely to suspend The School and its Appointments. 
297 
school on account of them. Yet measles is often a 
serious disease, and especially as leaving the lungs 
susceptible to the inroads of bronchitis and consump- 
tion in later years. All parents should be advised 
to keep children who have had measles out of school 
until the cough has entirely ceased. 
Small-pox is so well recognized as a fearful invasion, 
that we only need to refer to the fact that vaccination 
should be universal. 
Diphtheria has come to be so frequent and insidious 
a disease, that teachers, school officers, and parents 
should exercise the utmost care. Children should not 
be sent to school, from families where diphtheria is, 
until there is consent of the physician. The same is true 
as to scarlet-fever. The only way to prevent entire sus- 
pension of schools for a time is to prevent these diseases 
from spreading by the exercise of due precaution. Chapter XVII. 
WHAT TO DO WITH REFUSE, OR CAST-OFF MATERIAL. 
LIFE is made up of construction, waste, and repair. 
It is so arranged that in the very processes of life, 
as well as in the incidents of living, there is a constant 
production of what is variously called excretion, refuse, 
or offalling. It consists of materials which are organic, 
and so are changed by the various processes of decom- 
position. 
In addition to these, all organic nature about us is 
undergoing the same process. The material cast off is 
not at first, as a rule, hazardous to health. But if by 
retention or accumulation in quantity, decomposition 
goes on amid the living where there is not enough air 
to dilute and neutralize it or convey it away, or where 
there is not enough vegetation to appropriate it, it is 
left to taint the air, to pollute the water and the soil, 
and so to cause the perils of disease to animals, and 
especially to mankind. 
It therefore becomes necessary for us to understand 
that such material is not to be allowed to accumulate 
in and about human dwellings, but is to be disposed 
of by those methods which the various processes of 
nature indicate. 
2. One of the most radical of these is combustion. 
The description of the Gehenna outside of Jerusalem 
is that of a constant fire into which was thrown every- 
298 What to ho with Refuse. 
299 
tiling of a decayable nature, in order that it might 
be burned up. This plan has been adopted in some 
cities, especially in times of pestilence. It is claimed, 
with truth, that thus all refuse material is put beyond 
the risk of causing harm. The only question is, 
whether there are not other plans as available, and 
on other grounds to be commended. Inasmuch as 
in the arrangements of nature, such material is 
quickly appropriated and transformed without risk, 
the chief point seems to be, not to interrupt natural 
processes, or so arrange that they may take place 
where there can be no risk to health or life. Nature 
employs other forms of combustion besides fire. 
As to human secretions and excretions, a part is 
easily and readily disposed of in the usual methods 
of frequent bathing and ablutions. Water serves as a 
carrier and remover, and both air and moisture help 
to transform them into materials for plant-life. 
3. There is no rotation or conservation in nature 
more beautiful than that which relates to the relations 
of plant and animal life. Whatever is not so readily 
or rapidly disposed of only needs to be carried away 
to be mingled with earth in order that vegetation 
may fully appropriate it, and not leave any part for 
human inhalation. 
As a rule, nature allows a brief time in which such 
refuse is not dangerous, but at the same time forbids 
its storage in any form within human habitation, or 
where human beings congregate. Cesspools, garbage- 
heaps, middens, slop-holes, and all provisions for the 
accumulation of any such material amid the schools 
or the homes of the people, are to be regarded as haz- 300 
Hygiene. 
ardous. The only limitation to this statement is in 
the fact, that if such materials are mingled with the 
ground in only such quantities as it and its vegetation 
can dispose of, or is kept dry, or kept away from any 
heat or moisture, it will not undergo these dangerous 
decompositions. 
4. But because there is so much of moisture in the 
air and the earth, and because the heat so often ranges 
high, and reaches even to depths in the ground, it is 
not safe to adopt, as a system, the storage of any 
decayable, fermentable, or putrescible material. It has 
too often happened that what has been found for a long 
time to produce apparently no bad results, suddenly 
takes on that kind of change which either deteriorates 
or poisons the air or water, and so causes general ill- 
health or specific and dangerous maladies. 
Hence there is the one uniform rule as to all in- 
habited places, that such matter should not accumulate, 
or if there are arrangements for temporary storage, 
there should be such kind of storage, and such timely 
and orderly removal, as will greatly reduce the risk. 
It is also to be remembered, that, where there are light 
and heat and air, and open ventilation, as in the 
compost-heat in the barn-yard, nature often conducts 
such processes without any peril, whereas similar de- 
composition taking place in heated cesspools or in 
accumulated varieties of mingled refuse, may cause the 
greatest disturbance. 
5. It is also more perilous because such underground 
accumulations are reached by the varying water-level 
in the ground. So when heavy rains come, or when 
the earth has been kept wet by absence of sun and What to do with Refuse. 
301 
air, the little rills of ground-water carry polluted 
matter into the wells, there to mingle with the potable 
water-supply. It is known that many a case of fever 
or flux occurs from this cause. 
The opposite of this sometimes occurs in some soils 
or ground structure. The wells have been kept full, 
and the material at the distance has been kept covered 
with water. But a sudden and prolonged drought 
lowers the well-water, and so the well becomes the 
drain for a greater area. This polluted water is drawn 
off toward the well, while the uncovered mass is left 
to hasten to more rapid decomposition because of the 
heat and partial dryness. 
6. Too often the bad art of man interrupts and 
overcomes this conservatism of nature. Sometimes the 
results are merely such pollution of air, or such dete- 
rioration of water, as only causes a family or an indi- 
vidual to be less healthy, and to be complaining of 
various departures from a feeling of real wellness. 
Some, with good vital force, become adjusted to the 
condition because of their natural vigor, while others 
go into some form of ill-health. Occasionally the result 
is, to a whole community, a specific epidemic like 
typhoid fever. 
We have an analogue to this in typhus fever, where 
filthy houses, filthy yards, and filthy living induce the 
typhus, ship, or jail fever, which consumes multitudes, 
and provides a contagion that seizes upon those who 
live amid healthy surroundings. 
7. It is not necessary to specify all the various forms 
of accumulation, or the various methods by which cast- 
off materials are retained in close proximity or not 302 
Hygiene. 
disposed of in a safe way. It is enough to know that 
cleanliness means, not merely neatness, but such man- 
agement of person and things, of self and surroundings, 
of food and of clothing, of heat and air, of soil and 
dwelling, of school-house and grounds, as will cause all 
refuse, all decayable or organic matter, to be disposed 
of in such a way as not to imperil health. In doing 
this we may only have to let natural processes have 
their way, or to imitate them. In other cases, we have 
so far changed natural conditions as to need to make 
compensation by artificial methods. 
Thus, while, in general, the use of fire, earth, air, 
and water are sufficient to take care of such products, 
sometimes we need to call into use some special disin- 
fectant, as chloride of lime, to destroy the exciting 
cause, or as sulphate of iron, to interrupt its progress, 
or plaster or charcoal, to absorb its results, and thus 
to deliver animal life from its dangers. 
8. It is far more important to appreciate the prin- 
ciple here involved, than it is, in this connection, to 
give all the details by which it is to be accomplished. 
Personal cleanliness and perfect housekeeping are the 
beginnings. The watchfulness of prevention will much 
limit the accumulation of very many decayable matters. 
The fire will dispose of very much of dry refuse. In 
the structural arrangements, which are made for the 
less easily disposable matters, the necessity of a proper 
method will be so felt that the careful householder 
will see to it that satisfactory arrangements are made, 
and that proper administration is exercised. No mat- 
ters of science and art have been more fully studied, 
and safe methods will not fail to come to the notice What to do with Refuse. 
303 
of those who understand the possible and too often 
actual evils from accumulations of refuse. 
9. Where, on account of odors, or the suspicion of 
foul accumulations or dangerous pipes or sewers, disin- 
fectants are needed, the following will be found con- 
venient. 
Draughts of air may be used for all floating foulness; 
dry rubbing for all easily detached foulness; wiping 
and water scrubbing for all attached foulness. 
Hot air. Clothing or bedding is cleansed by being 
put in a furnace of dry heat of from 230° to 300° F. 
It should be subjected to the heat for about one hour. 
Hot water. Very hot or boiling water is applicable 
to the cleansing of all garments, utensils, etc., admitting 
of such a method. Put them in when the water is quite 
hot, and allow it to come to the boiling-point. Where 
garments have been soiled, it is well to throw them 
first into a tub containing a disinfectant solution, and 
from it transfer them to the hot water. If too soiled 
for renovation, they should be destroyed by fire. 
To disinfect a room or building, so needing disin- 
fection that its contents and surfaces cannot be easily 
dealt with singly, close the room or building, its 
windows, doors, and chimneys, so as to exclude the 
outer air as far as possible. Break roll-sulphur in small 
pieces, place it on an iron plate or other metallic dish, 
and set this on a pair of tongs, or other crossbar, over 
an iron pot in which there is water, or over a large 
box of sand, so as to avoid danger of fire from small 
particles of burning sulphur. Light it by a few hot 
coals, or some alcohol poured around the sulphur and 
lighted. Then leave, and shut the door after you. 304 
Hygiene. 
Three pounds of sulphur is sufficient for 1,000 cubic 
feet of space. The sulphur will convert all the oxygen 
of the air into sulphurous acid, and all organic particles 
are likely to be changed. Keep the room closed three 
hours after the burning has ceased, and then air well 
four hours before occupying. Clothing and bedding 
needing disinfection may be hung on lines and left in 
the room. Most furniture is not permanently injured, 
but needs dry wiping, and then washing off afterwards. 
10. Chloride of lime is a valuable disinfectant, chiefly 
because it contains from 25 to 30 per cent of chlorine, 
which is liberated under proper methods of use. It 
needs slight moistening, frequent stirring, and some- 
times the addition of an acid, as vinegar or common 
spirits of salt. The test of its efficiency is that the odor 
of it be kept constantly perceptible. 
One-half pound of it to a gallon of soft water is good 
for cleansing utensils, sinks, water-closets, drains, etc. 
One ounce to a gallon of water suffices for linen, which 
must not be left long in the solution, but be wrung out 
in fresh water. During an epidemic, sprinkle dry 
chloride of lime over contents of vaults, sinks, and cess- 
pools, etc., daily. 
Solution of chlorinated soda, usually known as Labar- 
raque’s solution, is a convenient liquid preparation, 
valuable for use in saucers in the sick-room, or in 
utensils. Its odor should be perceptible to any person 
entering the room. 
The chlorides are not to be used with carbolic acid. 
Sulphate of iron (copperas) when used is dissolved 
in water in the proportion of one and a half pounds to 
a gallon of water, for soil, sewers, etc. What to bo with Refuse. 
305 
Sulphate of zinc and common salt, dissolved together 
in water, in the proportion of four ounces of sulphate 
and two ounces of salt to the gallon, are used for cloth- 
ing, bed-linen, etc. 
One-half pound of sulphate of iron (copperas or 
green vitriol), or one ounce of sulphate of zinc (white 
vitriol), or one ounce of sulphate of copper (blue 
vitriol), or one ounce chloride of zinc (butter of zinc), 
or one ounce of chloride of lime (bleaching-powder), 
put to a quart of water, answer similar purposes as 
disinfectants. 
11. The following are also valuable. 
Solution of corrosive sublimate. One ounce to eight gal- 
lons of water. It should be colored with indigo to prevent 
its being mistaken for pure water. 
Commercial sulphuric acid. One pint to eight gallons 
of water. 
The following, because of its mild odor, may be used 
by those who object to the odor of chlorine, or that of 
the other disinfectants. 
Thymol solution. Two drams of thymol (crystals) dis- 
solved in ten drams of alcohol, twenty drams of glycerine, 
and one gallon of hot water. It gives a slight pleasant 
odor. 
Lime; plaster; charcoal; dry earth; sifted ashes. All 
these have value, chiefly to be tested by the rapidity 
with which they correct odors. Fresh-slaked lime should 
be scattered in all places of foul odor. It, or charcoal 
or plaster, may be scattered over heaps emitting foul 
odor. Calx-powder is made by pounding one bushel of 
fresh dry charcoal and two bushels of stone-lime, and 
mixing them, and is of great practical use. 306 
Hygiene. 
All these substances absorb foul gases, and dry up 
moisture, and so help to retard decomposition, or ab- 
sorb its results. Where lump-charcoal is used, it may 
be refitted for use by reheating it. Quick-lime and 
ground-plaster should not be used where they may be 
washed into pipes, as they form lime-soap or obstruct 
by hardening. Chapter XVIII. 
THE NERVOUS SYSTEM, AND ITS RELATION TO HEALTH. 
HAVING studied sufficiently for hygienic purposes 
the bony system by which the framework is sus- 
tained, the joints by which it is made capable of 
motion, the muscles by which it is moved, the stomach 
and other apparatus by which food is received, digested, 
and assimilated, the blood which is the chief liquid for 
supply, and the heart, lungs, and vessels of circulation 
and distribution, we now come to inquire into the 
system which presides over all as a force for motion 
and sensation. This is known as the nervous system. 
Dalton defines the function of the nervous system 
to be, “ to associate the different parts of the body in 
such a manner that stimulus applied to one organ 
may excite the activity of another.” It is the presid- 
ing force by which the coordination, cooperation, and 
rhythm of the whole machinery is secured. 
2. The nervous system, although often spoken of thus 
by one term, has two great divisions. 
The first is known both as the cerebro-spinal system, 
and the nervous system of animal life. It is made up 
of the brain, the spinal cord, and the cerebral and spinal 
nerves, and the plexuses or nerve-bundles connected there- 
with. 
The second is known as the great sympathetic or 
ganglionic system. It is called by Bichat, the nervous 
307 308 
Hygiene. 
system of organic life, and by Dalton, the nervous sys- 
tem of vegetative life. 
It is called the sympathetic system, because, mostly 
through it, all parts of the general system are brought 
into sympathy. 
It is called ganglionic, not because the other system 
has no ganglia, but because this system so largely 
abounds in ganglia. 
It is called the system of organic life, because it forms 
the chief plexuses about the heart and stomach, and has 
most to do with the action of great central organs. Its 
nervous centers (ganglia) are situated anteriorly, at the 
junction of the vertebrae of the spinal column, and are 
connected by intermediate cords or nerve-fibers. They 
thus form a chain alongside of the vertebral column. 
It is fortunately placed mostly beyond our control, or 
else we might forget to keep the heart beating. Dr. 
John Brown, in his little book on Health, has, as a 
frontispiece, the hand of the Creator clasping the heart 
and regulating its motion, and beneath it the motto, 
“ For in Him we live and move and have our being.” 
It is this nervous system that gives to the heart its 
motion, and that enables life to carry on its processes. 
3. The cerebro-spinal system begins with the cerebrum 
or brain, and is continued through the spinal column. 
The cerebrum is encased in the hard structure of bone 
which forms the cranium or head, and then has three 
coverings of membrane. The brain substance consists 
of two hemispheres, so that, in a sense, it may be called 
a double organ, as are the eyes, ears, etc. At the base 
of these there is a lobe or offset known as the cere- 
bellum. It has especially to do with the rhythm or The Nervous System and Health. 
309 
coordination of muscular action. The degree to which 
this is affected in intoxication points to the rapid and 
profound impression made upon the brain. Each of 
these hemispheres is composed of two substances, so 
distinct in fact and in appearance as to have the 
names of white and gray nervous matter. The white 
nerve substance is everywhere an organ of transmission. 
It is so composed of fibers as sometimes to be called 
fibrous tissue, and each fiber or filament is a tubular 
membrane, in the interior of which is a semi-fluid 
matter. Then through the center of the fiber is a 
gray thread, which is known as the axis cylinder, and 
is probably the most essential part. 
These fibers run parallel to each other, as the threads 
of a skein of silk, varying in size from 20V0 to 12 o‘o~o 
of an inch in diameter. They are smallest in the 
brain and spinal cord, and largest in the nerve 
trunks. These nerve fibers are collected in bundles 
of larger or smaller size. 
4. A nerve is made up of several bundles. More or 
less of the fibers and branches are made by the divis- 
ion of these bundles into smaller ones. The white 
substance constitutes a large portion of the central 
part of the cerebrum, and of the mass near where the 
spinal canal starts out from the brain, and known as 
the cerebellum. The gray substance thus seems like 
a cortex or bark, covering the white or inner mass. 
But in the spinal cord, the white portions form the 
exterior part. The whole of the substance of nerve 
trunks and branches is made up of it, except as they 
are stiffened by some areolar tissue interwoven to give 
them firmness. 310 
Hygiene. 
5. The gray nervous matter, which is thus the cover- 
ing in the brain and the central portion in the spinal 
cord, is found in considerable mass at the base of the 
brain, as it extends to form the center of the spinal 
cord. It consists of cells embedded in granular matter 
with a kind of granular pigment which gives it the 
gray color. This gray matter, wherever it is found 
collected in any part of the system, is called a gan- 
glion. These are secondary nervous centers, smaller 
and less complex than the brain. They are found 
in the cerebro-spinal system, at the posterior roots of 
all the spinal nerves, where they come out between 
the vertebrae as well as at points of nerve distribution. 
The sympathetic system is to such a degree made up 
of ganglia or aggregated gray matter as often to be 
called the ganglionic system. 
6. The spinal cord is but the continuation of the 
brain, and, like it, is protected by a bony structure made 
up by the vertebrae with intermediate spaces between, 
through which nerves branch out to be distributed to 
the whole body. 
The brain and spinal cord are so arranged that 
the right side of the brain is connected with the left 
side of the cord, and the right side of the cord with 
the left of the brain. It is because of this arrangement 
that injury to one side of the brain affects the opposite 
side of the body. The weight of the brain is about 
three pounds, and that of the spinal cord about one- 
thirtieth as much. 
7. We next come to notice the nerves, which come 
from this cerebro-spinal system. Those known as the 
cranial nerves come out from the medulla oblongata, The Nervous System and Health. 
311 
which is near the cerebellum, and is the cranial por- 
tion of the spinal cord. 
A process of white nerve-fiber connects the cerebrum, 
the cerebellum, and the medulla oblongata. 
The cranial nerves succeed each other in pairs from 
in front backward as follows: 
1st pair. Olfactory, or nerves of smell. 
2d pair. Optic, or nerves of sight. 
These two are almost processes or extensions of the 
brain, as if to bring it into direct contact with the 
outer world. 
3. Motores Oculi, which as nerves of motion supply most 
of the muscles of the eye. 
4. Pathetic. This, a very small nerve, supplies one of 
the muscles of the eye. It was called pathetic because 
it moves the muscle of the eye which is claimed to give 
it most expression. 
5. Trifacial. This is the largest cranial nerve. It has two 
roots (motor and sensory) like those from the spinal canal, 
and like them it has a ganglion at the root of its pos- 
terior part. It is the great nerve of motion and sensation 
for the entire face. Some well-known affections of the 
muscles of the face, and local neuralgias, arise from cold 
or other irritation of this nerve or some of its many 
branches. Thus we have facial paralysis, or that painful 
affection known as tic-doloreux. 
6. Abducens. This is a small motor nerve to one of the 
muscles of the eye. 
7. Facial, also called portio dura, from its hard texture. 
It supplies some of the muscles of the face, the interior 
ear, and the parotid gland, and often has to do with face 
and ear ache. 312 
Hygiene. 
8. Auditory, or portio mollis. It is a nerve of sensation 
distributed only to the middle ear. 
9. Glosso-Pharyngeal. This is partly a nerve of taste and 
partly of motion to the muscles of the pharynx. 
10. The Pneumogastric, or par vagum. It is called pneumo- 
gastric because so plentifully distributed to the lungs and 
Anterior 
■ lobe. 
Corpus 
callosum. 
Posterior 
lobe. 
Middle 
lobe. 
Nerves 
with 
numbers 
as given 
in text. 
Cerebel- 
lum. 
Medulla 
oblongata. 
FIG. XXIV. —Right side view of Human Brain, showing Cerebral 
Lobes and Cranial Nerves of Cerebellum, etc. 
the stomach, and par vagum, because so widely distributed 
to the heart, liver, etc. It has both motor and sensitive 
filaments, and ganglia. It has more extended distribution 
than any other of the cranial nerves, and in some respects 
is the most vital of them all. 
Figure XXIV. shows the relative positions. The Nervous System and Health. 
313 
11. Spinal Accessory. So called because a part of it is 
accessory to the tenth pair. A part of it arises from the 
lateral track of the cord and gathers up fibers along the 
cervical portion of the spinal cord. 
12. Hypoglossal, or chief motor nerve of the tongue. 
8. All these nerves are more or less connected with 
the white and gray matter of the brain. They inoscu- 
late variously with each other by ganglia or plexuses, 
and often motor and sensory filaments and white and 
gray matter are brought into contact or communica- 
tion. 
There is thus a series of independent yet cooperative 
forces made harmonious by one presiding Maker; in 
parts so under the control of the will, and in other 
parts so independent of it, as to accomplish all that 
can be done by will-power, and all that is necessary 
to be done without it. 
We have noted thus briefly the cranial nerves, be- 
cause, as thus exhibited, we can come more easily to 
the idea that both as nerves of sensation and of motion, 
they have relation to our own personal and hygienic 
management. 
Those least under our control, and meant to be inde- 
pendent of it, may, by disorder or abuse, so become 
involved as to change their rhythm of independent 
action into the most distressing contortions and spasms 
of movement. Others under our wills may be so 
wrongly educated as to be sources of pain rather than 
of pleasure. They will generally take care of them- 
selves, if all the rest of the body is rightly kept. But 
if there is disorder of body, of will, of emotion, instead 
of being our instruments for self-control, they become 
our most perplexing enemies. 314 
Hygiene. 
The system of nerve life is much like the delicate 
mainspring of a watch, which we do not need to 
fully understand. But we must learn not to abuse 
the instrument which contains such complicated work. 
We are finding out that just as there is an unper- 
ceived change which takes place in the minute mole- 
cules or structure of iron, by and repeated strain, 
known as the fatigue-work of iron, so we may produce 
functional and organic changes of nerves which unfit 
them for the work for which they were intended. 
9. The ultimate accomplishment of all education is 
to secure normal action of the entire nervous system; 
to secure for it the best conditions for health, and to 
prevent that impairment which gives rise to so many 
ailments. This glance at its minute complexity, and 
its relation to our inner selves and to the outer world, 
exhibits the fact that upon it chiefly depends all success 
in training the human being. This fact is all the more 
weighty and significant, because we are realizing that 
nervous impairment is becoming more frequent, that 
educational methods too often seem to increase it, and 
that great attention needs to be directed to such care of 
the body as will secure the normal action of all parts 
of this, its most delicate structure. Overstrain and 
overwork, if making their record here, have touched 
most vital parts. It will not do to load the mind with 
information, and in the act break down the material 
structure on which effectiveness depends. 
While what we have thus far noted is the portion of 
the nervous system allied most closely to the mind, 
we need also to follow the completion of the cerebro- 
spinal system, as found within and along the spinal 
column, and the ganglionic system. The Nervous System and Health. 
315 
This figure shows the human brain (lower surface), 
the spinal column, and the cranial and spinal nerves. 
Tissue between 
Hemispheres. 
Anterior Lobe. 
Cranial Nerves. 
Middle Lobe. 
Medulla Oblongata. 
Cerebellum. 
First Spinal Nerve. 
; Brachial Plexus. 
Dorsal Nerves. 
Lumbar Nerves. 
Lumbar Plexus. 
" Sacral Plexus. 
FIG. XXV. —Showing the Human Brain, and its processes. 
10. Coming forth from the column, between the ver- 
tebrse of the backbone, are 31 pairs of nerves. Each 
one arises by two roots, an anterior or motor and a 316 
Hygiene. 
posterior or sensitive root. The posterior roots have each 
a ganglion, except that it is, in some cases, wanting in 
the fifth pair. The motor are called the efferent {ex, out 
of, fero, to bear) and the sensory afferent {ad, to, fero, to 
bear) nerves. 
“ All the power of causing muscular contraction 
which a spinal nerve possesses is lodged in the fibers 
which compose its anterior roots ; and all the power of 
giving rise to sensation in those of its posterior roots. 
Hence the anterior roots are commonty called motor, 
and the posterior sensory. A sensory nerve is a nerve 
which, when active, brings an impulse to the central 
organ, or is afferent, and a motor nerve, a nerve which 
carries away an impulse from the organ, or is efferent. 
“ When a limb, as we say, ‘ goes to sleep,’ it is be- 
cause the nerves supplying it have been subjected to 
sufficient pressure to destroy the nervous continuity 
of the fibers. We lose voluntary control over, and sen- 
sation in, the limb, and these powers are only gradually 
restored as that nervous continuity returns.” 
11. The grouping of the spinal nerves is as fol- 
lows : — 
Cervical 8 pairs. 
Dorsal 12 “ 
Lumbar 5 “ 
Sacral 5 “ 
Coccygeal 1 “ 
These pass out through the intervertebral foramina on 
either side of the spinal column. The two roots, which 
are united just before passing out, after passing out 
divide into two branches of mingled fiber, an anterior 
branch supplying the front of the body and a posterior The Nervous System and Health. 
317 
and smaller branch supplying the back. These nerves 
anastomose in various parts and connections so as to 
form plexuses, and these variously intercommunicate 
with each other, with the cervical nerves, and with the 
sympathetic ganglia. Among the most prominent are 
the cervical, brachial, lumbar, and sacral groups, from 
which nerves are distributed in various directions, giving 
motion and sensation to the most distant parts. 
12. The sympathetic system of nerves is the other re- 
maining system now to be considered. 
It consists of a series of ganglia, or knots of gray 
matter, connected by intervening cords, and extending 
along each side of the cerebro-spinal column from the 
head to the last bone of its column, communicating 
with all the nerves of the body, and giving branches 
to all the internal organs and viscera. As some of 
these organs are supplied by it exclusively, it came to 
be called the nervous system of organic life. 
Each ganglion may be considered a distinct center 
giving off branches of communication, (a) between the 
ganglia (b) with the cerebral or spinal nerves or (c) to 
communicate with the other sympathetic filaments and 
the viscera and the ganglia located in the thorax, 
abdomen, and pelvis. These ganglia are about as large 
as a very small bean. 
The chief ganglia of the sympathetic nerves may be 
classified as 
Cranial or Cephalic 4 
Dorsal 12 
Sacral . 5 
Cervical 3 
Lumbar 4 
Coccygeal 1 318 
Hygiene. 
From these we have nerves given off to various parts, 
and they are so distributed that we have besides a 
cardiac ganglion, cardiac plexuses, and pulmonary plex- 
uses. The great splanchnic nerve, itself a sort of plexus, 
ends in the semilunar ganglia which form a part of a 
gangliform circle behind the stomach, known as the 
solar or epigastric plexus. From it we have ten or more 
plexuses to the stomach, liver, spleen, kidney, etc. 
The two semilunar ganglia of the solar plexus are 
the largest ganglia in the body. It is because of this 
that a blow upon the stomach is so often serious, and 
sometimes quickly fatal. 
The lumbar and sacral ganglia give off many nerves 
and filaments, but form only two or three plexuses. 
The nerves which govern the walls or muscular fiber 
of the arteries, veins, and capillaries are called vaso- 
motor nerves. Impressions made upon them result in a 
change of the caliber of these vessels, and greatly affect 
our sensations. 
Special regions of the spinal cord have the special 
function of acting as centers for these vaso-motor nerves. 
13. As we view these two great divisions of the 
nervous system, namely, the cerebro-spinal and the sympa- 
thetic, we find them closely inosculating and connecting, 
and having many points of resemblance. Both are com- 
posed of white and gray matter. Although the white 
substance predominates in the brain and spinal cord and 
nerves, and the gray in the sympathetic system, yet the 
brain itself is made up of ganglia, and gray matter is 
found in it and in the spinal cord. In both, the white 
matter has to do with conveying impression and the 
gray with generating force, the one being as the battery 
and the other as the telegraphic wires. The Nervous System and Health. 
319 
Through the one, the system of animal life is con- 
trolled in parts by the will. In the other, the system 
of organic or vegetable life, the action is spontaneous, 
or without will power. Yet they are in close corre- 
spondence. Also in the cerebro-spinal system, in what 
is known as reflex action, we have a response of motor 
nerves to impressions and muscular action therefrom 
without any intervention of sensory or volitional power, 
as when the eyelids wink before a blow. 
14. The stimulus or irritation applied voluntarily or 
involuntarily, directly or indirectly, to the ends of the 
afferent or sensory nerves gives rise to a molecular 
change, which is propagated along the nerves to the 
spinal cord, with which they are connected, and so is 
transmitted to the motor or efferent nerves, which pass 
from the spinal cord to the muscles affected. The brain 
also gives rise to some reflex actions, but the spinal cord 
is spoken of as the central organ of reflex action. The 
power is possessed only by the gray matter, and is not 
possessed by any ordinary nerve. 
This reflex power, in which the sensory nerves carry 
a message to the central organ, which quicker than 
thought is reflected to the motor nerves, and so results 
in action, is a process constantly going on. Prof. Iduxley 
well illustrates it, thus: — 
“ Let us consider what takes place in such an act as 
reading aloud. In this case, the whole attention of the 
mind is, or ought to be, bent upon the subject-matter of the 
book, while a multitude of most delicate muscular actions 
are going on, of which the reader is not in the slightest 
degree aware. Thus the book is held in the hand at the 
right distance from the eyes; the eyes are moved from side 320 
Hygiene. 
to side, over the lines and up and down the pages. Further, 
the most delicately adjusted and rapid movements of the 
muscles of the lips, tongue, and throat, of the laryngeal 
and respiratory muscles, are involved in the production of 
speech. Perhaps the reader is standing up, and accompany- 
ing the reading with appropriate gestures. And yet every 
one of these muscular acts may be performed with utter 
on his part, of anything but the sense of 
words in the book. In other words, they are reflex acts.” 
The reflex actions proper to the spinal cord itself are 
natural, and are involved in the structure of the cord 
and the properties of its constituents. By the help of 
the brain we may acquire an infinity of artificial reflex 
actions, that is to say, an action may require all our 
attention and all our volition for its first, or second, or 
third performance, but by frequent repetition it becomes, 
in a manner, part of our organization, and is performed 
without volition, or even consciousness. 
The possibility of all education is based upon the exist- 
ence of this power which the nervous system possesses 
of organizing conscious actions into more or less uncon- 
scious, or reflex, operations. It may be laid down as a 
rule, that if any two mental states be called up together, 
or in succession, with due frequency and vividness, the 
subsequent production of one of them will suffice to call 
up the other, and that whether we desire it or not. 
The object of intellectual education is to create such 
indissoluble associations of our ideas of things, in the 
order and relation in which they occur in nature; that 
of moral education is to unite as fixedly the ideas of 
evil deeds with those of pain and degradation, and of 
good actions with those of pleasure and nobleness. The Nervous System and Health. 
321 
Very much of intellectual acquirement is the conver- 
sion of volition into automatic or spontaneous power. 
15. We are not able to detect a circulating fluid in 
nerves so distinctly as in blood-vessels. Yet from what 
we have found of the tubular structure of nerve fiber it 
is not mere poetry to speak of a circulating, vital, or 
nervous force. The state of the fluid may have very 
much to do with nervous action. Just as the waves 
within the ear-labyrinth are played upon by the waves 
of sound, so this nervous complexity is operated upon 
by a variety of forces. While brain and cord and 
ganglia everywhere have their own action as centers, 
they also have relations to each other. While each plays 
its own part, the whole complicated machinery moves 
on with a rhythm of continuous harmony so wonderful 
that we can but admire and adore. 
16. Nerve action is the foundation element in health 
and disease. We need to avail ourselves of such forces 
as we find conducive to good nerve health, and to 
avoid those which interfere therewith. 
When we do not fully understand a machine in 
all its mechanism and details, we may, nevertheless, 
become quite aware of the conditions under which it 
was made to run. So one may come to know very 
much about the functions of the nervous system and 
the conditions of its healthy exercise, and so treat it 
well, without an entire knowledge of its character or 
mechanism. 
It is hard to get it out of order, numberless as are 
the present instances of its disorder. But once out of 
order, it will not be mended by any common tinkering. 
Nay, it is so much a high-wrought and divinely wrought 322 
Hygiene. 
excellency, that human hands too often fail in attempts 
at such attainments of skill. 
Beware that it be not jostled about too rudely, or 
handled carelessly lest the machinery becomes hope- 
lessly ajar, or very difficult to repair. It lias to do 
with physical, mental, and moral hygiene. Many a life 
is wasted or made erratic, because the error is made 
here. Not only the body weakens, but the mind loses 
its resiliency, and harmony of thought and action are 
impaired. 
The great principle involved in a proper care of the 
nervous system is so to care for the body in all its 
parts as that it shall be properly nourished, and each 
function properly performed. Knowledge and experience 
must teach us the limits of nerve endurance. 
When the eye becomes tired it is time to stop or change 
the glare of light, or in some other way seek restoration. 
So with every other organ, and with the mind itself. 
17. The greatest difficulty with the nervous system is 
that it so often fails to have the aid of discipline and 
of will power. As there is tonic to the whole body in 
air, water, and sunshine, so there is tonic to the ner- 
vous system in willing obedience to that which is right 
in discipline, training, and self-control. We fortify the 
nervous system in studying how to control action, 
motion, sensation, volition, and all that appertains to 
that wonderful border-land between the voluntary and 
involuntary, of which brain and nerves are the com- 
municating telephones. 
Nervous diseases perhaps more than any other class 
of diseases are the outcome of wrong methods of con- 
ducting the daily discipline of voluntary life. A person The Nervous System and Health. 
323 
may become over emotional by over indulgence of the 
sensibilities; or ungovernable, because too frequently 
yielding to appetites or habits or passions; or unstrung, 
because the toil of thought has claimed too many hours 
and caused undue fatigue. 
It is one of the results of the study of Hygiene, 
that it puts so many not only on guard, but into the 
practice of methods of consistent life. Thus there is 
adjustment of work to ability, of desire, to necessary 
control, until still greater powers are acquired, or the 
person learns the limitation of his power, and conforms 
his desires and his aspirations thereto. It also teaches 
us how much the nervous system is capable of educa- 
tion, how drill and discipline may correct abnormal 
tendencies. Thus a proper and healthy control of the 
nervous system may be maintained, and in many cases 
re-acquired, after symptoms of disorder have appeared. 
18. Alcohol, etc. — The great risk incurred in the 
use of alcohol, opium, chloral, tobacco, and the long 
array of narcotics and stimulants, is that they make their 
quickest and profoundest impression on the nervous 
systems of animal and organic life. They touch the 
very mainsprings of life, and in a way that too often 
shows that we are tampering with that part of our- 
selves which we should touch the least frequently and 
the least rudely, unless we accurately know the ultimate 
as well as immediate effects of that touch. Ere we 
know it, we may disturb fibers and motions and sensa- 
tions which it is hard to restore. We know not whether 
we are only affecting function, and that temporarily, 
or whether we are changing structure. Too often it 
is a process of education by which we impart real and 324 
Hygiene. 
automatic desire in the wrong direction, and change of 
structure results. In the case of alcohol, we have 
abundant evidence that vital organs are engorged by 
the paralysis of the vaso-motor system. 
19. Overwork and overstrain do their harm to the same 
intricate network, unless there is rest, recreation, and 
amusement. Most of all, sleep is the great panacea for 
tired nerves, and must never be shortened by those 
who would preserve the vigor of life, in its central 
axis, in the hidings of its power. If for any reason 
there has been loss of sleep, there must be compen- 
sation therefor. 
Recreation and rest are additional aids. Food of 
easy digestion and in increased quantities will, to some 
degree, make amends for loss of sleep. But all who 
labor must plan for such amount of sleep as seems to 
be required. We know of a distinguished writer who 
keeps an account of his lost sleep-time, and makes it 
up by going to bed in the daytime each week enough 
to make up for any loss. It is far better to let work 
and rest alternate in close relationship. 
Other invigorations of the nervous system are to 
be sought from exercise, change of air and scene, 
and sometimes by the use of special medicinal tonics. 
Let it ever be remembered that, in the ultimate 
analysis, the welfare of the nervous system is the 
radical aim and effort of all hygienic care. Out of it 
are the issues of life, for it is the mainspring of each 
organ, the presiding genius of each function, the basis 
and substance of all life. 
20. The care of nervous condition, and the invigora- 
tion of the nervous system, are important parts of The Nervous System and Health. 
325 
the training and instruction of children. A headache 
is never to be trifled with, by urging the child on 
to intellectual work. It is a noble tact, a tadus 
eruditus, to be able to discern when the child labors 
too much in study, or is perplexed into worry by 
overwork. Trials with scores of children, oft repeated, 
have shown that no classes do as well in mental arith- 
metic in the afternoon as in the forenoon. Changes 
of study, and of the order of different grades of study, 
can be made to contribute to vigor. Irritability or 
discouragement in pupils is often mental tire. 
Any distinctly nervous symptoms, such as twitching, 
sobbing, and excessive laughing, indicate the need 
of attention to the health, and the supply of such 
foods and tonics as are of recognized value. Spasm 
of any kind in children, even if no after effects appear, 
is to be taken as full notice that the nervous system 
is being impaired. Teachers need to study and discern 
the temperament of pupils and the nerve tonicity. 
There is no wear and tear like that of a disturbed 
nervous organization. 
21. That plan of education which does not take 
into account the nervous organization is very defective. 
A correct plan of education must include what is some- 
times called mental and moral hygiene. “ It teaches the 
child to understand that he is the trustee of his body, 
by giving him general outlines of his duty to it and its 
wonderful power and readiness to serve him in return, 
so that he will instinctively respect it, and be really in- 
terested in taking good care of it, and acquire a natural 
presence of mind with which to meet its special and 
sudden requirements, without in any morbid manner 326 
Hygiene. 
dwelling upon it and its functions. It instructs him in 
the general effects and uses of the emotions; that truth, 
unselfishness, courage, cheerfulness, patience, and kind- 
ness all tend to make him happy, and others around 
him happy, and that happiness is a great help, and 
indeed a necessity, to health. It shows him that undue 
emulation in study or play leads to overstrain of the 
body, and to the hateful vices of envy and selfishness,— 
vices which produce emotions directly and harmfully 
affecting health, — and that it is far better to be indi- 
vidually well, noble, and happy, than to be successfully 
competitive at so great a cost. It teaches that giving 
way to ill-temper produces special disturbances hurtful 
to body and mind; that bad habits, such as the use of 
alcohol, tobacco, opium, or other narcotic substances, 
have most mischievous effects on the nervous system; 
and are essentially silly, ignoble, and degrading; that 
the only true pride consists in being too proud to abuse 
the body intrusted to us, and too proud to be swrayed 
by any opinions but those of the worthy and of the 
good.” We must put our attention upon this broad 
study of Hygiene in all its relations, as we do upon 
the study of History or Geography, or any other branch. 
Only it is the trunk and timber of the tree of knowledge 
more than it is a branch. It is not only that care and 
exercise develop muscular power. The teaching is a dis- 
cipline of will-power, an exercise of self-control, an aiding 
of the nervous system in that coordination and coopera- 
tion on which true life and true living so much depend. 
Industry, bravery, patience, prudence, system, equipoise, 
common sense, come out of such knowledge and such 
discipline. The Nervous System and Health. 
327 
22. True education is not only consistent with health, 
but is a culture of health. A trained mind not only 
has possession of itself for thought, but for the control 
of physical life. It looks after the condition of the 
machine which it is to operate and upon which its in- 
tegrity and functions depend. 
We must be convinced that the body stands in need 
of exercise and discipline as well as the mind, and then 
seek to learn the process by which it is to be trained 
and its good ability secured. In learning how to order 
the body aright, and how to have it fulfil our orders, 
we at the same time get mental and moral stamina. It 
is when seeking to develop the wholeness of our being 
that we get the benefits of education. 
This, far more than what is spoken of as talent, 
gives success in life, and make it easy for the human 
animal to have power and influence both mental and 
moral. It is this well-fed, well-slept, well-trained, well- 
exercised nervous system, more than anything else 
that has to do with our whole well-being. This means 
all that can be meant for us in this world, and in- 
cludes much that is hopeful for us as to the next. Chapter XIX. 
THE SENSES. 
IN considering the nervous system, we have had occa- 
sion to notice nerves as the media or source of 
sensation and motion. Muscles contract in response to 
the motor or efferent nerves which are distributed to 
them. These nerves derive their activity from the 
central nervous organ with which the motor and 
sensory nerves are connected. The central organ is 
sometimes the brain, sometimes the spinal cord, and 
sometimes almost a prolongation of the brain, as with 
some of the special senses. The ganglia, and the vari- 
ous meshes and intertwining of nerves we have before 
noticed, also serve as points of departure. 
Whatever this central point for motion or response 
be, it is thrown into activity by the sensory or afferent 
nerves to which the motor or efferent nerves respond. 
These, too, in various ways, connect with the central 
organ on the one hand, and with parts of the body on 
the other. The change which thus takes place first in 
the sensory or afferent nerve generally results from some 
external impression. 
2. Most, if not all the voluntary movements of the 
body are affected by the process of stimulus proceeding 
from without, as has been indicated, and this, as quick 
as thought, is reflected back by what is called reflex 
328 The Senses. 
329 
action. In addition to what we may call natural reflex 
action, we have seen that multitudes of reflex actions 
become acquired, so that things at first done through 
teaching come to be done automatically. Indeed, habit 
makes such actions as natural as instinct, or non-ac- 
quired actions, by the molecular changes which take 
place. 
When, as frequently happens, movements or actions 
so affect our sensory nerves that we become conscious 
of them, we speak of them as sensations. These are a 
part of our consciousness, which, like primary beliefs 
and intuitions, have to be accepted as ultimate and 
indescribable facts. 
3. We are aware of great variety in sensations, hut it 
is not always easy to trace them to their center. Some, 
like fatigue, restlessness, despondency, irritability, we can- 
not assign to any particular place. Others, like faintness, 
or tendency to tears or emotions, we may or may not 
trace to some external impression. Some of them are 
natural, some of them the first slight advances toward 
disease. Volition strongly intermingles with them; edu- 
cation teaches which of them are to be cultivated, which 
resisted, and the method best adapted in either direction. 
All this class of sensations, while they may be affected 
by the external world, inform us nothing about it. They 
are purely subjective sensations; yet as we speak of 
educating the senses, we are also to recognize that sensa- 
tions may he retained as normal and made more acute, 
or may be made abnormal and morbid. 
We are able, quite distinctly, to separate them from 
what we are used to call the senses, and yet they admit 
of training. 330 
Hygiene. 
4. There is one sense, known as the muscular sense, 
which it is difficult to classify. While having the same 
general origin and mode of operation as the sensations, 
it is in its power of receiving external impressions so 
analogous to some of the organs of sense as that many 
now classify it therewith. 
This muscular sense is the sense by which we judge 
of the relative weight of a body, or the degree of resistance 
it offers to our effort to move it. It is different from 
touch or pressure or contact. It enables the person to 
form some idea of the weight of an article or its degree 
of resistance. The idea is not formed by looking at it or 
feeling of it, but by the muscular act of lifting. Some 
would include this as a result of external sensations, 
and classify it with the senses of touch, taste, smell, hear- 
ing, and sight. 
5. Most of our sensations are compounds of different 
sensations with each other, or with ideas and emotions. 
Aristotle claimed that each of the five senses was only a 
modification of the sense of touch. Some have claimed 
the parental love of children as a special sense. The 
vocal power, or that of speech, some regard as a special 
sense. How two recognized senses act in combination 
is seen in the perception or sense we call taste, which, 
in its result, is largely made up of smell and touch. 
Many of the conclusions we arrive at are dependent 
upon the exercise of mind or judgment, so that the 
brain is in a special sense as much an organ of sense 
or sensation as the eye or ear. 
So complex is the source of our information as to the 
external world, that it is difficult to use such words as 
sensation, emotion, volition, and perception with pre- The Senses. 
331 
cision. When I touch anything, my conclusions as to 
it are derived partly from sight, or experience, or judg- 
ment. By feeling of variously shaped blocks with the 
eye shut, we may render doubtful what would otherwise 
have been a clear perception of feeling. Sir Humphry 
Davy, in his early life, was assisting Dr. Beddoes, who 
cured diseases by inhalation of gas. Davy, in order to 
ascertain temperature, placed a thermometer under the 
man’s tongue. The patient fancied that this was the 
wonderful inhaler, and had such a sensation of inhala- 
tion that the use of the thermometer, and nothing else, 
was continued for several days, and evident benefit re- 
sulted. “Our notions of singleness or roundness are 
really highly complex judgments, based upon a few 
simple sensations, and when the ordinary conditions of 
these judgments are reversed, the judgment is also re- 
versed.” 
6. The cultivation and control of the senses is of 
great importance, both to render them accurate or auto- 
matic, and to prevent what is useless or harmful. How 
far single senses can be trained and made to replace 
others is illustrated in the blind and the deaf. There is, 
even without these extremes, a correlation which is won- 
derful. Sense, sensation, emotion, volition, thought, and 
judgment intertwine as wonderfully as does the wonder- 
ful machinery of the nervous system, and common sense 
is the presiding governor needed for the whole. Each 
teacher needs to appreciate the bearing of education 
upon sensations as well as upon the senses. We must 
know something of our great instrument, the nervous 
system, and play properly upon its chords, if we would 
rightly reach the mind of which it is the machinery. 332 
Hygiene. 
With these preliminary suggestions, we proceed to notice 
the senses which have heretofore been classed as the 
five senses. 
7. The Sense of Touch. — Our general sensibility is 
dependent upon the sensitive nerves of the cerebro- 
spinal system, which form the chief network amid the 
papillae of the skin. Thus the skin becomes the chief 
medium of general sensibility; for sense of heat and 
cold, of roundness and solidity, and of moisture, 
fluidity, or felt motion, and various other forms of 
sensation, are acquired here. The quality of the sen- 
sation is much determined by the thickness of this 
covering, or by the fact that the deeper layer of the 
skin is raised up into elevations known as papillae. 
Loops of capillary vessels enter these, and the sensory 
nerve-fibers distributed to the skin terminate in them. 
The sensibility of different parts seems to be principally 
decided by the number and prominence of these papillae. 
Valentin arranges the order of 'sensitive perception as 
follows: 
Tip of the tongue; palmar surface of the tips of 
the fingers; of the second phalanges, and the red 
surface of the lips; of the first phalanges, and the 
end of the nose; the dorsum of the tongue; the dorsal 
surface of the phalanges; the cheeks, and back of the 
hand, etc. While two points can be distinguished by 
the tips of the fingers, if but one-twelfth of an inch 
apart, the two points of a carpenter’s compass, three 
inches apart, may give but one sensation at the middle 
of the back. 
8. Because the skin and the mucous membrane of 
the nose, mouth, and throat share in this sensibility, The Senses. 
333 
differing in degree, but not in kind, we speak of touch 
as a general sense or sensibility, having no specialized 
organ. Button says of it, that it rectifies all the other 
senses. The modes in which it can be changed or 
developed are interesting. Even the impression which 
we sometimes have in the dark, that we are approach- 
ing a solid object, is a part of the sense of touch, as 
conveyed by the air. 
So far as heat and cold are concerned, and in some 
other cases, the sense is relative rather than absolute. 
Huxley illustrates it by three basins, one having ice- 
cold water, one containing water as hot as it can be 
borne, and one a mixture of the two. If the hand is 
placed in the last, after it has been in the hot water 
basin, it will feel cold, but if placed in it after being 
in the ice-cold basin it will feel warm. 
9. If the skin is brought too near the fire, it be- 
comes more sensitive to cold. Much itching of the 
skin, chilblains, chapped hands, etc., are not so much 
owing to degrees of cold, as to sudden changes. None 
suffer so much from cold feet and hands as those who 
hold them much by the fire after being cold. There 
are very many ways of disordering skin sensations, 
which are owing to the undue alternations, to un- 
evenness in the amount of clothing, difference of press- 
ure and friction, etc. If these sensations are at once 
heeded, and the disturbed part bathed with a little borax 
or soda-water or glycerine, and the suspected cause 
avoided, the trouble ceases. If the sensations are neg- 
lected many of the varied forms of skin irritation are 
produced. Change of garments or covering, change of 
thickness, and change of habit as to exposure, are of 
great benefit in such cases. 334 
Hygiene. 
10. What is known as the tactus eruditus, or learned 
touch, is, on the other hand, a proper and useful devel- 
opment of sensibility, and can be cultivated. Many 
of the arts depend on this. What we call handiwork 
is often the product of a cultivated touch as much 
as of a cultivated taste. We know an oculist who, 
in washing the hands and in the use of gloves, has 
in thought the preservation of his finger-touch, for the 
nice operations he performs. So the seamstress, the 
decorator, and all classes of expert artists, are greatly 
dependent upon this cultivated sense of touch. Per- 
sons who have been maimed have been taught to 
write with the toes as well as others do with the 
fingers. 
In the blind we see this sense developed to such a 
marvellous degree as to indicate the possibility of high 
training. We are learning more and more how much 
all education is a training of the senses; their capaci- 
ties, their record, and their ability, depending not less 
upon the uses to which they are put than upon their 
original endowments. 
11. Taste.—The senses of taste, smell, hearing, and 
sight are those most frequently recognized as depend- 
ing upon specially localized organs. 
The sense of taste is located in the mucous mem- 
brane of the tongue, the soft palate, and the fauces. 
The mucous membrane of the tongue is raised into 
papillae of various shapes and sizes supplied with sen- 
sory filaments from the trifacial and glosso-phaiyngeal 
nerves. The same nerves give to the tongue general 
sensibility, so that it is an addition to the general 
sense of touch in this way. While it is, by the ordi- The Senses. 
335 
nary sensibility of touch, in the mouth that we per- 
ceive hardness and softness, temperature, etc., the special 
sense of taste receives the impressions of flavor, acidity 
and alkalinity, and much of what goes to make relish 
or dislike, and the appetite. Even these are modified 
by the sense of smell, which can also reach it through 
the posterior openings of the nose. Thus in the mouth 
the three senses cooperate, and give to the gateway 
of the breathing and digestive systems their combined 
guard. 
12. The sense of taste is an example of how, by 
habit, sensations which are unpleasant, or actually pain- 
ful, may become agreeable. We find such to be the case 
as to very many sauces and condiments, which at first 
irritate and burn the mucous membrane of the mouth 
and throat so as to suspend taste, and even require 
treatment. Thus cayenne pepper and other severe 
irritants, are made pleasant to the taste, while at the 
same time they are doing their serious damage to 
the minute vessels and tubules of internal organs. 
So tobacco, at first unpleasant, and causing a stinging 
sensation, is craved by the taste, until chewing, rub- 
bing of snuff, and dipping have come to be practiced 
by those of both sexes, and of many climes. 
Still more, the alcoholic beverage, which at first burns 
the mouth and throat so as to require much weaken- 
ing, is, after a time, passed down the throat, fiery and 
stinging, with a relish. The perverted taste even makes 
the mouth to water for it, and the taste to crave it 
with an insatiable craving. 
There are some appetites, which are but the de- 
mands of nature for food and for replenishment, but 336 
Hygiene. 
too much of what we call appetite is perverted taste, 
asking more sensitively for harmful things than for 
the actual foods and sustenance of life. It is a famil- 
iar illustration, not only of how taste can be cultivated, 
changed, and perverted, but also illustrates how any 
sense may be either so educated, and improved or 
deranged and degraded, as to give to it the highest 
possibilities for good or for evil. 
13. The sense of smell has for its organ that part of 
the nose lined by mucous membrane, upon which the 
filaments of the olfactory nerve are outspread, namely, 
the mucous membrane of the superior and middle 
turbinated or scroll-like bones. 
At the upper portion is a delicate plate of the ethmoid 
bone, called the cribriform plate, from its sieve-like holes. 
Only this perforated, horizontal plate of bone separates 
the nasal cavity from the brain, so that the olfactory 
nerve, like the optic, is really more like a prolongation 
of brain than a distinct nerve. 
The broad bulbs of the olfactory lobes rest upon the 
upper side of the cribriform plate, and from these the 
olfactory filaments spread out on the superior and 
middle turbinal or spongy bones, which are permeated 
by air-cavities connecting with the nasal fossa. 
14. In the quiet flow of air to the lungs, the air of the 
upper chamber is not freely mingled with the former, 
and so when we wish to perceive faint odors we sniff 
the air so as to carry it into these interstices. The 
ill-effects of the use of snuff must be apparent to any 
one who will consider that this delicate sieve mem- 
brane is its receptacle. We sneeze through irritation of 
the fifth pair of nerves, which gives to the nose general The Senses. 
337 
sensibility to the acrid or pungent substances which are 
felt rather than smelt. 
It is evident how readily odors or air can be made 
to reach this olfactory chamber, and it is not improbable 
that the action of sedatives upon a headache, and even 
of anesthetics on the brain, is not merely due to inha- 
lation into the lungs, but also to the vaporous emana- 
tions which may pass almost in contact with the brain, 
or be conveyed directly thereto. 
As it is the upper portion of the nose that receives 
the impression of odors, we may smell not only through 
the nose, but through the open mouth. This is especially 
so in connection with the eating of food, and is service- 
able in warning us of that which is disagreeable or in 
adding to the relish of that which is savory. 
15. In a cold we lose in part the sense of smell, owing 
to the swelling of the membrane over the turbinated 
bones. Smell is much dependent upon the immediate 
contact of organic particles with moving air, chiefly in 
the upper nose, and so is impaired by anything that 
obstructs clear nasal breathing. 
The sense of smell is the simplest of all, so far as 
it relates to dependence upon association with other 
senses. We get from it little idea of quantity, size, 
or weight, and it acts, not by contact, but upon vapor. 
The general sensibility of the mucous membrane 
is quite distinct from the special sense of odor. It is 
therefore, typically, a special sense. 
It is a common observation, that mental associations 
are awakened by odors, more than by the impression of 
any other sense. Dreams are often caused by the foul- 
ness of the air. Odors will awaken some persons more 
readily than noises. 338 
Hygiene. 
16. Hearing. — The sense of hearing lias its special 
organ, the ear, and a special nerve known as the auditory- 
nerve. 
As the nerve of smell is spread out on the mucous 
surface along the turbinated bones of the nose, so the 
filaments of the auditory nerve are spread out in what 
is known as the internal ear. The ear, for convenience, 
is spoken of as consisting of three parts, — the external, 
the middle, and the internal ear. 
The external ear consists of the expanded portion, 
external to the head, — and known as the auricle or 
pinna, — and the meatus or auditory canal leading to 
the middle ear. The extension at the side of the head 
has been termed the “ handsome volute ” to the human 
capital, and its lobes, the hanging ornaments to the 
head. It is mostly a firm cartilage, covered by skin, 
and so provided with muscles as to have firmness, 
and «uch slight motion as may be required. In fact, 
there are muscles for drawing the ear upward, back- 
ward, and forward, but the muscular fibers are not so 
abundant in man as in some of the lower animals. 
17. In deaf persons, however, these muscles serve to 
change the shape of the ear, and make of it more of a 
tunnel for the collection of sound. The availability of 
an instrument, now in use for aiding hearing by push- 
ing the ear forward, shows that the mere shape of the 
ear is no unimportant matter. Its size, shape, and con- 
volutions have direct reference to its special purpose, 
namely, to make it effective in collecting the waves of 
air which produce sound. If put on upside down, or 
sidewise, it would not so well serve this purpose. 
There is much difference in the shape of ears, as The Senses. 
339 
much or more than in that of any other organ, and it 
is not infrequent that the two ears vary in some par- 
ticulars. They are not so uniform as the eyes, but, as 
Semicircular Canals. 
• Incus or Anvil-bone. 
- External Meatus 
Auditorius. 
Vestibule. 
Cochlea. _ 
Concha. 
Auditory Nerve. 
Fenestra Rotunda. 
Stapes. 
Inside of Membrana 
Tympani. 
Malleus or Hammer- 
bone. 
Lobules... 
FIG. XXVI. —Diagram of the Ear. 
we cannot look well at the whole surface of both ears 
at the same time, slight variations are not noticed. 
The above figure gives the general structure of the 
ear. 
18. The auditory canal is an oval cylinder reaching 340 
Hygiene. 
from the concha, or root, of the external ear to the 
membrana tympani, or drum, which separates the external 
from the middle ear. It is about one and one-fourth 
inches in length, and so curved as to be higher in the 
middle than at either extremity, and a little narrower 
there. About one-half inch of the canal is cartilagi- 
nous, and the rest bony, or in the bony structure. 
Two or three fissures in the anterior part make this 
portion, which is lined by a continuation of the ex- 
ternal integument, slightly movable. The skin and 
membrane lining the ear is furnished with hairs and 
oil-glands, and further in are wax-glands which secrete 
the cerumen or wax. Both of these aid to keep out 
insects and foreign substances. The ear needs washing 
as well as the face, and the ends of the little fingers, 
when wet at the usual washing time, are well fitted 
to moisten the ear, while the towel or a soft rag will 
remove any accumulation. This gentle care of the ear 
is often neglected. 
19. The middle ear, or tympanum, forms an irregular 
cavity in the petrous bone of the cranium. 
The cavity is less than one-half inch in depth, and 
about one-fourth inch in its irregular diameter. It is 
closed in front by the membrana tympani, the delicate 
membrane stretched obliquely across the edge of the 
tympanum. This vibrates to the waves of sound, and 
transmits the vibrations to the small bones of the middle 
ear. The membrana tympani is impervious to fluids. 
The membrane is made tense or relaxed by the muscles 
of the middle ear. 
The further end of the middle ear is bounded l>y 
the outer surface of the labyrinth or internal ear. The Senses. 
341 
Air is admitted to the middle ear through a tube 
known as the Eustachian tube, which extends from the 
ear to the throat, and is about one and one-half inches 
long. The entrance of this opening from the mouth or 
pharynx to the middle ear keeps the air therein at the 
same pressure or tension as the external atmosphere. 
This often induces deaf people to open the mouth to 
hear, as thus some sound is gathered. 
20. As we dissect the tympanitic membrane off from 
the entrance to the middle ear, we find that it is at- 
tached, on its inner side, to a small bone called the mal- 
leus. It is of hammer-like shape, the handle of which 
is fastened to the membrane, but so as to be movable. 
Its head fits into the cup of another little bone further 
in, called the incus or anvil, which has two prongs, one 
of which is attached to the margin of the opening of 
certain cells known as the mastoid cells, and the other 
ends in a little ball. This again articulates with a third 
bone, called the stapes or stirrup. These three bones are 
known as the ossicles of the ear. 
This third bone is fastened to the fenestra ovalis, 
which is the little opening leading from the middle 
ear to that part of the labyrinth or internal ear known 
as the vestibule. The fastening is by means of a cir- 
cular band composed of elastic tissue. Below, and 
slightly behind this, there is another little opening closed 
by a membrane, and known as the fenestra rotunda, 
leading to that part of the labyrinth or internal ear 
known as the cochlea. The neck of the stapes gives 
attachment to the stapedius muscle. 
21. These bones are connected together, and with the 
middle ear, by three ligaments. They have at their 342 
Hygiene. 
articulations cartilage and synovial membrane fitting 
them for motion. Two muscles tighten or relax the 
tympanitic membrane, and one probably so alters the 
angle of the stapes as to compress the contents of 
the vestibular portion of the internal ear. The tensor 
and stapedius muscles, acting together, tighten the tym- 
panic membrane, and modify or restrict its vibrations. 
All this minute delicacy of structure indicates the need 
of protecting the ear from injury. 
In addition to this chain of bones in this little rock 
cavern of the middle ear, there is on the posterior wall 
a larger opening, leading by several smaller ones to 
cells known as mastoid cells, which are in the mastoid 
process of the temporal bone, and vary in number 
and size. These multiply the vibratory surface, and 
so have to do with resonance of sound. The whole 
middle ear, as thus described, is lined with mucous 
membrane sufficiently moist. 
It is apparent that the construction of this organ is 
such as fits it to be responsive to the play of some 
delicate ethereal power, and that no harpsichord of 
human mechanism was ever better fitted to respond 
to the human touch than is this to the tactile vibra- 
tions of the air. With all this wonderful machinery of 
the middle ear, the bones and canals are so minute, 
that the entire cavity would not contain over a half- 
teaspoonful of liquid. 
22. The third part, or internal car, already incident- 
ally referred to, is called in general the labyrinth. It is 
a collection of cavities in the petrous bone known as 
the vestibule, the semicircular canals, and the cochlea. 
The semicircular canals may be included as a part of 
the vestibule. The Senses. 
343 
The vestibule begins at the point where the middle 
and internal ears join, namely, at the fenestra ovalis, or 
end of the stapes, and has an irregular diameter of 
about one-fifth of an inch. At its farthest extremity 
is the meatus auditorius internus, which is the opening 
at which the auditory nerve issues from the brain to 
be spread out in its manifold filaments in the internal 
ear. 
The semicircular canals are three in number, and 
above and behind the vestibule, but so much a part 
thereof as by many to be described as an appendage, 
or a part. They almost describe a circle, having a 
tubular diameter of about one-twentieth of an inch, 
and beginning and ending in the vestibule. This 
would make six openings, but as two of them run 
together, there are but five openings into the labyrinth. 
At one end of each, where it joins the vestibule, 
there is a dilatation called the ampulla. Delicate but 
stiff nerve filaments abound in the inner walls of the 
ampulla, and these respond to any vibration occasioned 
in the watery fluid about them. Figure XXVII. gives 
a good idea of the wonderful construction of this musical 
instrument. 
The cochlea (snail-shell) is a spirally-coiled canal, 
rather below the vestibule, in length and breadth 
only about one-fourth of an inch, consisting of two 
parts, the central axis or modiolus, and the spiral canal 
coiled two and one-half times around it, so as to make 
a length of about one and one-half inches. This 
spiral canal communicates with the middle ear by one 
of its openings. It has a thin membrane like the 
drum, and forms a mouth or funnel to the cochlea. 344 
Hygiene. 
The interior of this spiral canal of the cochlea, lined 
by fibro-serous membrane, and known as the scala 
media, is divided into two passages by a septum, upon 
which nerve tubules are distributed. 
23. The inner surface of all the osseous labyrinth of 
the internal ear, made up of the vestibule with its semi- 
circular canal, and the cochlea with its spiral canal, 
is lined by a fibro-serous membrane containing a very 
little fluid. The fluid it secretes is known as the 
Cells of Claudius. 
Cells of Corti. 
Outer spiral nerve 
fibers. 
The inner hair-cells.' 
Outer and inner rods 
or pillars of Corti’s 
arch. 
Ascending nerve 
fibers. 
Holes for passage of nerve 
fibers of the organ 
of Corti. 
Cells lining the sulcus 
spiralis. 
The auditory teeth. 
PIG. XXVII. — Terminal Auditory Apparatus. 
liquor cotunnii, or perilymph, which thus fills also the 
scala media, or spiral canal of the cochlea. 
In the vestibule and semicircular canals, it divides 
the osseous labyrinth from another sac, the mem- 
branous labyrinth yet to be considered, but in the 
cochlea, the fibro-serous membrane lines the two sur- 
faces of the bony part of the lamina, dividing the spiral 
canal in which so many nerve filaments are distributed. 
It forms the membrane completing the division of the 
canal, and so is bathed with perilymph. The Senses. 
345 
Inside of all this is another sac containing fluid, 
and this is known as the endolymph. 
In the perilymph and endolymph are certain small, 
mobile, hard bodies, and the ultimate filaments of the 
auditory nerves are so distributed upon the walls of 
the sacs that their terminations must be knocked by 
the vibrations of these small, hard bodies, should any- 
thing set them in motion. 
24. The vibrations of the fluid contents of the sacs 
themselves suffice to affect the filaments of the audi- 
tory nerve under the action of sound, just as the retina 
of the eye responds to light, but this is greatly inten- 
sified by these sand particles, just as the sand on the 
sea-shore gives vibrations to the waves. 
Sound acting on the drum, or tympanic membrane, 
is, through the action of the three small bones before 
noticed, made to impinge on the fenestra ovalis, which 
leads to the internal ear, and so causes vibration 
throughout the fluid of the perilymph. This, in turn, 
reaches the fenestra rotunda and the endolymph, with 
its otolithes or gritty particles, and so the filaments of 
the auditory nerve are reached. 
The auditory nerve at the meatus auditorious internus 
divides into two branches, known from their distri- 
bution as the vestibular and cochlear, and these again 
divide into branches and filaments until the nerve 
itself is outspread into a nervous membrane. 
It lines the surface of the modiolus or calumella of the 
cochlea, and spreads itself like minute harp-strings over 
the spiral canal. These filaments are known as the 
fibers of Corti. With the microscope we can count 3,000 
or more. Fig. XXVII. shows this internal ear apparatus. 346 
Hygiene. 
Professor C. F. Brackett simplifies the description in 
this way. The tympanum is a drum-head placed 
obliquely. The three bones, as so many levers, serve 
to change its tension. These in turn connect with 
a bladder-like sac filled with water, inside of which 
is another movable bladder-sac, also filled with fluid. 
In contact with it, nerve filaments are spread out. It 
has little sand-particles in it. 
25. Now, when the tympanum is impinged by waves 
of sound, the effect is felt first on the bones, and con- 
veyed to the first sac of water, and then to the second, 
setting its waves in motion, and these, with the grits 
impinge on each nerve fiber, and so the effect, soft or 
hard, high or low sound, is struck against these nerves 
and conveyed to the seat of consciousness. 
Professor Bonders states the time occupied in the 
transmission of a sensation from the ear to the brain, 
the formation of a judgment, and the transmission of 
volition from the brain to the hand, at .09 of a second, 
while in the case of sight it is .15 or .17 of a second. 
At one point, the nerve fibers are arranged harp-like, 
so as to give 400 sensitive cords to each octave, of 
which the interval of space is one-sixty-sixth of a note. 
Even this description gives but little idea of the 
intricacy and marvellous art of arrangement. The won- 
ders of the ear are only less thought of than those 
of the eye, because the organ is so little seen, and was 
not so early investigated. Sound, in its record and 
action and response, is as remarkable as light. Its 
relation to knowledge, to voice, to music, and to 
life is so delicate and intricate, that lost hearing is 
often harder to restore than lost sight. Tiie Senses. 
347 
26. Of the hygiene of the internal ear we know noth- 
ing. That of the middle only concerns what we can do 
for the Eustachian tube which connects it with the 
throat, and for the tympanic membrane, or drum, 
which separates it from the external canal of the ear. 
Now and then, sudden or prolonged deafness occurs 
from enlarged tonsils, or unhealthy condition of the 
pharynx part of the throat, or from swelling of the 
tubes, or the impaction of mucous in them. 
It has been necessary to refer to the anatomy, and 
its mode of function, because of its intimate relation 
to the middle ear. This lias relations with the throat 
and the external ear in such a way as makes the care 
of it most important. Nearly all the cases of severe 
or permanent deafness involve the middle ear. As its 
function, and often its organic condition, depends much 
on the access of air through the eustachian canal 
leading from the throat, it must be kept in a healthy 
condition. Unfortunately, sore-throat, enlarged tonsils, 
severe cold, and various conditions of the fauces or 
region of the palate, too often give rise to disease 
of the middle ear. The condition of the throat should 
therefore early attract attention. Noises in the head, 
or dullness, or over sensitiveness to sound, should lead 
to inquiry as to its condition. Frequent rinsing of the 
throat is of great service. 
27. The membrane of the ear is sometimes affected 
or destroyed by disease of the middle ear. Scarlet-lever 
sometimes causes disease here. One or more of the 
minute bones of the ear sometimes penetrate the drum, 
and are removed, causing loss of hearing. 
The membrana tympani, or drum, may suffer inflam- 348 
Hygiene. 
mation. It is occasionally fractured by the discharge 
of cannon or other sudden noises. Ear-ache is never to 
be trifled with, as only the skilled physician can know 
whether it indicates disease of the internal or external 
ear. 
Injuries to the external ear may occur from injury to 
the drum, or from cold or inflammation. Sometimes the 
wax or natural secretion of the ear becomes hard so as 
to cause irritation or deafness. This is especially liable 
to occur when the ear is much exposed to dust, or is 
not well cared for by washing. Sometimes children 
put beans or pebbles into the ear, which, from the nar- 
rowness and uneven caliber of its canal, are difficult of 
extraction. Their removal is made more difficult be- 
cause of the unsuccessful efforts of unskilled persons. 
28. If the ears are systematically cleansed in the 
manner already indicated at the usual washing-time, 
and if they are not irritated, or unduly exposed to cold, 
they are not likely to need other attention. Soft linen 
or tissue-paper answers well for drying them. When the 
Avax is tenacious or the orifice dry, the use of warm 
borax-water, so that some of it gets into the ear, is 
effectual. Where there is tenderness of the ear, or where 
there is exposure to intense cold, a minute piece of soft 
wool in the ear is a good protection. Ear-ache is often 
caused by the retarded secretions. The habit of keeping 
wool or cotton in the ear is not a good one. Pains about 
the ear are often neuralgic in their character. All sharp 
pains of the ear should be controlled by an opiate 
until the doctor is summoned. 
In cultivating the ear for music it is not so susceptible 
of weariness as is the eye, but nevertheless there may The Senses. 
349 
be too continuous application. Like all the senses, hear- 
ing needs alternations of rest. 
We are all familiar with the degree to which delicacy, 
correctness of aural sensation and perception admit of 
cultivation. There is nothing in any organ of sense so 
wonderful as the mode in which we are made conscious 
of degrees in pitch, quality, and the various variations 
in sound. Chapter XX. 
THE SENSE OF VISION. 
The sense of sight is exercised through the eye as 
its organ, and the pair of nerves known as the 
optic nerves. In its wonderful mechanism, the eye im- 
presses itself at once upon our attention more directly 
than any other organ of sense. It seems like a window 
to the intellect, through which the outer world looks 
in, and by which much of the material for thought 
and knowledge is conveyed to the mind. It also 
seems as an organ through which the mind looks out, 
and so gives us impressions as to the faculties and 
emotions. 
2. It may be defined as an optical instrument, so 
fitted to light as to receive the images of objects, and 
to give to the mind a right impression thereof. It is 
so provided with machinery for protection and adjust- 
ment as to suit it for all reasonable variations of dis- 
tance, or of surrounding media. 
As it is more illustrative and simpler to consider the 
eye from without inward, we will begin with the 
appendages which have to do with its protection, and 
its more perfect usefulness. 
3. The eyebrows form an arch over the cavity for 
the eye, and are so set with short, thick hairs as to 
impede sweat, dust, or other material from settling in 
and about the eye. They serve also for the attachment 
350 The Sense of Vision. 
351 
of muscles which aid in controlling the amount of light 
admitted to the eye. Under a sudden blaze of light, we 
quickly, and almost involuntarily, draw down the eye- 
brows and diminish the aperture. 
The eyelids are two thin folds of integument, the upper 
being more movable and larger. Both are furnished 
with two or three rows of hairs, which by their setting, 
and their celerity of movement, afford protection to the 
eye. The tarsal cartilages on their edges gives them form 
and support. On their inner surface they are set with 
glands known as the Meibomian glands. There are about 
twenty or thirty on each lid. These resemble the oil- 
glands of the skin, and keep the mucous membrane of 
the lids and of the eye surface bathed with a watery and 
slightly mucilaginous secretion, which prevents dryness 
and adhesion of the lids. The form of inflammation 
commonly known as sty is a stoppage of some one or 
more of these glands. The mucous membrane which 
covers the eyelids on the inside, and is reflected over a 
part of the eye, is called the conjunctiva. 
At the inner canthus or corner of the eye is a small 
red spot known as the caruncula lachrymalis. It is made 
up of follicles like a gland, and produces a whitish 
secretion a little different from that of the Meibomian 
glands, such as is often found at the inner corner. 
4. The lachrymal or tear apparatus consists of a 
gland situated in a depression at the upper outer angle 
of the orbit, about the size of a small plum-stone, 
having ducts six or eight in number, which open by 
rows of capillary tubes on the upper and outer part 
of the conjunctiva or mucous membrane of the upper 
eyelid, and are so arranged as to moisten the whole 352 
Hygiene. 
eye, winking being a special means of distributing the 
moisture. Under strong emotion the flow becomes 
greater, and our feelings are expressed by tears. 
But under usual circumstances there must needs be 
an arrangement for carrying off this secretion without 
having it always flowing out over the eyelids. To this 
end we have at the inner canthus, or corner of the 
eye, small orifices in each eyelid constantly open, which 
can be seen, and are known as puncta lachrymalis. These 
lead into capillary canals called canaliculi, and these 
again into a little reservoir known as the lachrymal sac. 
From this goes a duct known as the nasal duct, which 
carries the superfluous tears into the nose. Its value is 
appreciated by those who, having had this duct ob- 
structed, are compelled constantly to use the handker- 
chief. A chaplain of the House of Representatives was 
gratified at the impression he was making on a Con- 
gressman, until informed that his use of his handker- 
chief was owing to this infirmity. 
The eye being provided with these appendages to 
secure its cleansing and protection, is so situated in a 
bony orbit as that it is well protected on all other 
sides from injury. The cavity is formed by the join- 
ing of several bones, and thus an arch or socket is 
made about this precious organ. 
5. The ball of the eye, or eye proper, may be de- 
scribed as a body spherical in form, of diameter a 
little under one inch, made up of several successive 
layers or coverings, between which are refracting media 
or humors. The optic, or special nerve of sight, enters 
this orbit from the posterior part, the whole being 
supplied with nerves and blood-vessels, and operated 
by several muscles. The Sense of Vision. 
353 
This figure will aid in the explanation of it. 
These layers or coverings are three in number. They 
are as follows: (a) the sclerotic coat and cornea, (b) 
the choroid, iris, and ciliary processes, (c) the retina. 
The refracting media are three: (a) the aqueous 
humor, (b) the crystalline lens and capsule, and (c) 
the vitreous humor. 
Meibomian 
Glands. 
Crystalline 
Lens. 
Vitreous 
Humor. 
Elevated Muscle of 
Upper Lid. 
Ciliary Processes 
of Muscle. 
Superior Rectus 
Muscle. 
Sclerotic Coat. 
Choroid Coat. 
Aqueous Humor.: 
Pupil. 
Retina. 
Cornea. 
Iris. 
Optic Nerve. 
Adipose or Fatty- 
Tissue. 
Glands.-* 
Inferior Rectus 
Muscle. 
Sclerotic 
Coat. 
Retina. 
Choroid 
Coat. 
FIG. XXVIII. - Vertical Section of the Eye, 
As you look at another’s eye, you see first a whitish 
coat, in the center of which is a smaller disc, through 
which is an opening changing in size with the degree 
of light. The first is the sclerotic or hard coat of 
the eye, the second being the cornea, set in it like 
a watch-glass, and having the opening referred to. The 354 
Hygiene. 
cornea forms about one-sixth of the surface of the eye, 
and is a little longer in its transverse than in its 
vertical diameter. The muscles which move the eye 
are inserted into the sclerotic coat, and through it are 
distributed various nerves and blood-vessels needed for 
the sensibility and vitality of the eye structure. 
Removing this layer or covering of the eye, as you 
would the peel of an onion, a little transparent fluid 
exudes. This is what is known as the aqueous humor. 
It forms several drops, or four or five grains in weight, 
and has alkaline reaction. This aqueous humor fills 
the anterior chambers of the eye. It is adjacent to the 
sclerotic and cornea on their entire inner surface, and 
also to the next tunic, or coat of the eye. The space 
bounded in front by the cornea, and behind by the 
front of the iris and the ciliary ligament, is called the 
anterior chamber of the eye. 
6. The second coat of the eye, as we pass inward, is 
as if, taking off the outside covering of a ball, you found 
a second one made up, for instance, of muslin, silk, 
and linen pieces, instead of one covering such as the 
leatlier-like sclerotic and cornea. 
The strip, or circle in front, right behind the cornea, 
is called the iris, with its ciliary processes, — that by 
the edge, where the sclerotic, and its watch-glass the 
cornea, join, is called the ciliary ligament and muscle, 
and the part of the tunic, or covering making up the 
other five-sixths of the globe, is called the choroid coat. 
The iris, so called from its rainbow or varied colors, 
is that little colored center you see when you look 
into a person’s eye to tell whether he has black, gray, 
blue, or hazel eyes. The small black opening in it, The Sense of Vision. 
355 
which contracts or expands as the light is less or 
greater, is called the pupil. 
The iris is like a fold directly behind the cornea. It 
has its delicate fibers of tissue radiating toward the 
pupil, its muscular fibers for contracting the pupil, 
and its pigment cells. 
7. The ciliary processes consist of appendages or folds, 
formed by the plaiting of the middle and internal layer 
of the choroid coat, and arranged in a circle behind 
the iris, and around the edge of the lens. They are 
from sixty to eighty in number, their periphery being 
attached to the ciliary ligament. The central border 
is free. On its margin, which nearly corresponds with 
the juncture of the sclerotic and cornea, you can per- 
ceive a narrow white ring. This is the ciliary ligament 
and ciliary muscle, which form the edge of the iris, 
and so the continuation of the second coat of the eye 
as it merges into the remaining portion of the second 
coat, known as the choroid. 
The ciliary ligament connects the external and middle 
coat of the eye at this point. The ciliary muscle, 
Bowman supposes, is so placed as to draw the crystalline 
lens forward, and so adjust the eye for near vision. 
8. The choroid coat, which in extent very nearly cor- 
responds with the sclerotic part of the first coat, or tunic 
of the eye, is a vascular membrane of dark color, made 
up of three layers, in which blood-vessels abound. The 
inner layer is made up of cells, with pigment matter 
arranged in tesselated form. The cells are so delicate 
that a stream of water will wash the black substance 
off. Immediately behind the pupil, or opening into 
this iris, is the crystalline lens, through which all 356 
Hygiene. 
light must pass and be refracted. This lens, of which 
an eye-glass or spectacle may serve as an illustration, 
is a transparent body enclosed in a very elastic and 
transparent membrane known as the capsule of the 
lens. 
The lens is about one-third of an inch in its trans- 
verse diameter, and about one-fourth of an inch in 
depth. It is convex, both on its outside and its inside 
surface, but more on its inside, or rear surface. If we 
take off the capsule we find the lens made up of one 
peel after another, each layer of membrane being harder 
or denser than the next outer one, until we come to 
the hard, central nucleus. 
This capsule and lens has a suspensary ligament 
which aids to keep it in place. 
9. The retina forms the third coat, or tunic, of the 
eye. On its outer surface, it is in contact with the 
inside layer of the choroid, or second coat; on its inner 
surface with the vitreous, or third humor of the eye. 
This retina is a delicate nerve membrane, and by 
some has been styled the outspreading of the optic 
nerve with which it is continuous, just as the nerve of 
smell is spread out in the nose and the nerve of hear- 
ing in the ear. 
It is spoken of as made up of three membranes, the 
external, the middle or granular, and the internal or 
nervous. All the blood-vessels ramify freely through 
the internal layer. Upon this delicate membrane, after 
passing through the previous coats and humors of the 
eye, the images of external objects are received. The 
thin layer which connects the anterior margin of the 
retina with the surface of the crystalline lens is known 
as the zonula ciliaris. The Sense of Vision. 
357 
10. The cavity within this retina, or third tunic, 
into which light is admitted through the cornea, the 
aqueous humor, the iris, and the crystalline lens, is 
filled with what is known as the vitreous humor. The 
vitreous humor is an albuminous and very transparent 
jelly-like fluid, enclosed in a delicate membrane, and 
forms the chief part of the bulk of the inner eye. 
This humor thus enclosed is hollowed in front to the 
shape of the crystalline lens. It is also connected with 
its suspensory ligament. 
The optic nerve enters the globe of the eye at the 
posterior part, a little to the nasal side of the center, 
through the optic foramen, directly from the brain, and 
pierces the sclerotic and choroid coats, and expands 
into the nervous membrane of the retina. 
We noted, in the chapter on the nerves, how the two 
optic nerves cross before emerging from the brain. 
11. The ball or globe of the eye is moved by six 
muscles, two known as oblique and the other four as 
straight. 
These are inserted into the sclerotic coat of the eye, 
and, acting singly or together, roll the eye in many 
directions, and give it power of retraction in its orbit 
as well as of slight protrusion forward. 
The superior oblique muscle is especially worthy of 
note as having its line of direction changed by passing 
through a pulley at the internal angular process of 
the frontal bone, so that it can roll the eye inward and 
forward, and carry the pupil outward and downward. 
“ Such is the perfection of the mechanism, that the 
cornea is raised or lowered without the least lateral 
deviation, like the objective of a meridian-glass; and 358 
Hygiene. 
the eye perceives by this succession of movements if 
the image of a line on the retina deviates two ten- 
thousandths of an inch from the vertical.” 
12. We have thus considered all the apparatus con- 
cerned in carrying the sensation of light to the brain, 
and now we must needs see how the mechanism accom- 
plishes its object. This is necessary because so many 
Superior Oblique Muscle- 
Superior Rectus Muscle- 
Inferior Rectus Muscle 
External Rectus Muscle. 
Left Optic Nerve 
Motor-oculi Nerve. 
FIG. XXIX. —The Muscles of the Eyeball. 
errors of vision result from not understanding these 
relations. Light, which consists of undulations in an 
ethereal medium, is so modified in passing through the 
transparent portions of the eye as to form images of 
the objects from which it proceeds. From these images 
the brain derives correct impressions of the objects them- 
selves. 
If we go into a dark room and light a candle, how 
shall we throw an image of the candle on the wall? The Sense of Vision. 
359 
We can do it by taking a lens, say a piece of glass, 
convex on both sides, and, holding it between the 
candle and the wall, farther or nearer, until we find 
that it will cast the image. The point at which this 
image is best cast is called the focus. It will be 
brightened or dimmed, diminished or enlarged, as we 
change the candle nearer or farther from the lens. 
We will thus be able to determine at what distance we 
secure the greatest size consistent with distinctness. 
This is the right focus for that lens. Here we have 
the principle of the human eye. 
13. An image of the object to be looked at is to be 
made on the retina, which is the wall or surface on 
which it has been arranged that the image must be 
cast, in order that the brain may take cognizance of 
it, and receive such impressions as shall give an accu- 
rate conception of the object observed. 
Light is received through the watch-glass of the 
sclerotic or outer coat, namely, the cornea. Refraction, 
or the proper bending of the rays of light, depends 
somewhat on the convexity of the cornea. It also finds 
in the aqueous humor a medium of some refractive 
power, this humor being also of service in distending 
and giving shape to the anterior chamber of the eye. 
Light thus comes to the iris, which is a self-regulating 
diaphragm or curtain, with a hole in it, which expands 
or contracts to the stimulus of light, and so regulates 
the quantity, letting in or shutting out so much as is 
needed to secure a proper image of the object looked 
at. Longet calls it an “ intelligent diaphragm.” By 
cutting off side or marginal rays, it overcomes certain 
well-recognized optical defects which would otherwise 
result. 360 
Hygiene. 
The use of a diaphragm, or dark plate with a hole 
in the center, in the ordinary camera obscura, is for 
the same purpose. In perfecting many optical instru- 
ments, we learn to avail ourselves of mechanism simi- 
lar to that of the eye. But the iris has this great 
advantage, that it is self-regulating. 
14. Over all the inside of the choroid coat, which 
with the iris forms the second coat of the eye, and to 
which light thus gets access, there is a black pigment 
as well as over the posterior surface of the iris and 
ciliary processes. This, like the blackening of parts in 
the interior of the telescope and magic-lantern, serves 
to absorb scattering rays of light, and prevent such re- 
flection as would obscure vision. Where, as in albinos, 
there is an absence of pigment, there is imperfection 
of vision. 
Thus guarded against any sources of optical confusion, 
the light, passing through the pupil of the iris, comes 
to the crystalline lens, the design of which, like the 
lens used with the candle in the dark room, is to cast 
an image of the object seen, at the proper focus. This 
focus, in the case of the eye, is the retina, or third coat 
of the eye, the membrane which — the vitreous humor 
intervening — is to receive the image ready for the per- 
ception of the brain, or mind. This vitreous humor, 
with which light comes in contact, as it passes from the 
crystalline lens to the retina, not only gives shape to 
the globe of the eye by extending it, but has some 
office in connection with the refraction or proper adap- 
tation of light. Refraction, we have already noticed, 
is chiefly accomplished by the cornea and aqueous 
humor. The Sense of Vision. 
361 
If every part of the eye has, up to this point, done 
its duty, or been complete in its office and adjustments, 
the retina receives the perfect impression, and the object 
is correctly seeif. 
15. But as the eye has to deal with different degrees 
of light, it has constant occasion for adjustment in 
order that the retina may always be at the proper 
focus. If the image is thrown either in front of it, or 
so that the rays fall too far back, sight is imperfect. 
This adjustment occurs in various ways, by the 
action of the muscles, by the contraction or expansion 
of the pupil, by the refracting power of the different 
humors, by the absorption of the scattered rays, by 
the pigment, but chiefly by the fact that the crystalline 
lens can alter its convexity, and perhaps its position, 
in its adjustment of the vision to different distances. 
In instruments we have to change the lens, but the 
eye is self-adjusting. Tyndall, after some criticisms on 
what he calls its imperfections, says that, “as a prac- 
tical instrument, and taking into account the adjust- 
ment by which its defects are neutralized, it must ever 
remain a marvel to the reflecting mind.” If a person 
has a cornea more convex than usual, or if some other 
cause increases the refractive power of the eye, objects 
at a usual distance for good eyes are seen indistinctly, 
because the shadow is cast in front of the retina, or 
proper focus. Short-sightedness is the result, and there 
is need to wear concave glasses, which, by making rays 
diverge, counteract the excessive refractive power. 
Not only the shape of the cornea, but greater or less 
convexity of lens, has to do with near-sightedness. 
If the cornea is too flat, as often happens in old age, 362 
Hygiene. 
or if from any other cause refractive power is too 
small, the person is too long or far sighted, and the 
book for reading has to be held too far off. In this 
case convex glasses must be worn the rays 
converge, for the shadow is cast too far back. 
16. It is well to bear in mind, that “even in those 
phenomena which at first seem purely physical, we 
must not forget that the refracting media of the eye 
are organized, and cannot be compared, except by 
approximation, to inorganic bodies, on the form or 
density of which physicists base their calculations. 
This is necessarily the cause of the difference in the 
theories promulgated in regard to vision; for although 
the eye in some respects may be considered as an optical 
instrument, wre can never arrive at exact deductions 
by comparing organs analogous, or even similar in 
their construction, but different in their nature.” 
Behind the retina, no mortal has as yet described 
the mechanism, and yet the sensation of light occurs, 
and the brain takes such cognizance of the delicate 
undulations of the rippling light waves impressed on 
the retina, as, like a telegraphic record, to declare the 
meanings of form, shape, and color, and transform them 
into conceptions, perceptions, and living thoughts, reach- 
ing out to a great infinity of knowledge. 
The study of the eye involves, not merely a knowl- 
edge of optics, as presented in the text-books of physics, 
but also an appreciation of its complete adaptation to 
its design. As we study the contacts of mind and 
matter, it is all the clearer that these and their instru- 
ments were made by a Maker “ knowing how,” to an 
extent on which no shadow of doubt is thrown, except The Sense of Vision. 
363 
by certain philosophers, who, in the use of the senses 
provided, fail to realize their own finiteness in the 
midst of such infinite perfection. 
When we consider how much the eye is used and 
misused, and yet how seldom, comparatively, it fails 
in its work, we cannot but devoutly admire the won- 
derful power of this window for the brain which lets 
in so much of the light of the world, and is so much 
the expression of that intellect within, which has appro- 
priated knowledge, and made it the medium for bene- 
fiting the world. 
17. We now notice some of the more common affec- 
tions of the eye, which require hygienic forethought and 
care. 
The affections of the eye which are most frequent are 
those having to do with its appendages or chief outside 
protectors. These are the eyebrows, eyelids, the conjunc- 
tiva, or inner lining of the lids, and the lachrymal glands, 
with their secretions and ducts. Strange as it may seem, 
among the disfigurements of the face which have been 
called adornments, there has been either the removal 
of the hairs or the painting of the eyebrows so as to 
interfere with their natural purpose. A slight irritation 
of the minute glands in the eyelids is often the first sig- 
nal that the eye is being overtaxed. This also is the 
first signal that they are being subjected to bad air or 
improper light, or that there is congestion about them. 
The form of pimple known as a sty has its origin in 
these glands. The secretion from them helps to lubri- 
cate the eyelids, for the thousands of movements they 
make each day. If this secretion becomes viscid it acts 
as a direct irritant to the eyes. 364 
Hygiene. 
18. There is also a contagious form of inflammation 
of the lid-margins and of the roots of the eyelashes 
which does an immense amount of mischief, although 
it is not so often destructive to sight as is purulent 
ophthalmia. 
The careful washing of the eye each day with cool 
or cold water, and the avoidance of bright light, espe- 
cially in reading or study, is very important when the 
eye shows any affection of the lids. 
When the lids are disposed to stick together, they 
should be bathed at night along the edges with a little 
glycerine, or glycerine mixed with a solution of borax. 
If the eyelashes are at all fastened together in the morn- 
ing, a mild solution of soda or borax should be used. 
Too often the foundation is laid for a very troublesome 
irritation of the eyes by carelessness as to the lids. 
19. Besides this secretion there is another, more abun- 
dant, from a small gland for each eye, lodged in the 
orbit, on the outer side of the ball. This lachrymal 
gland has several small ducts opening on the inner por- 
tion of the eyelids. Its purpose is to furnish to the 
eye a constant cleansing water, which shall moisten and 
wash its surface, and then pass off through the duct 
before noticed into the cavity of the nose. If the eye 
be irritated by dust or pungent vapors, or if the emo- 
tions be greatly moved, the secretion from these lachry- 
mal glands comes faster than it can be carried off into 
the nasal ducts, and there is an overflow of tears. 
This also happens when the duct has become occluded. 
Of this the first symptom is a slight swelling in the 
inner corner or canthus of the eye. It should receive 
immediate attention. If neglected, a small abscess may The Sense of Vision. 
365 
form, and the duct become permanently destroyed, so 
as to cause a constant slight overflow of tears at this 
point. 
20. At the edge of the eyelids, the skin changes to 
a delicate vascular mucous membrane known as the 
conjunctiva, which lines the lids, and is reflected over the 
front of the eyeball. This membrane is highly suscepti- 
ble. Foul air, irritating substances, specks in the eye, or 
improper use of the eye, often cause its highly vascular 
structure to become congested. This is the usual form 
of sore eyes. It often passes on to a chronic form, in 
which the minute vessels, and the tissue surrounding 
them, become raised above the general surface of the 
conjunctiva, and so, in the form of granular lids, act 
as a foreign substance. 
There is no organ to which preventive treatment is 
more important than for the eye. At the beginning of 
excessive watering of the eye, a little rest, or the use 
of a slight alkali, as soda, or a slight astringent, as cold 
or lukewarm tea, is often of service. When there is 
any increase of trouble, skilled advice must early be 
sought. 
Those who have the care of children should be quick 
and careful to notice any disease or soreness of the eye. 
Not only the use of the same towel, but nearness to 
the secretions from sore eyes, often communicates dis- 
ease therefrom to the eyes of others. When specks of 
any kind get into the eye, if they are not sharp so as 
to have penetrated its coats, a holding of the eye still 
and shut until it is filled with tears will often wash 
out the offending substance. Rubbing of the eye is to 
be avoided. A turning of the upper lid, or a pulling 366 
Hygiene. 
down of the lower so as to see the speck and remove 
it with the twisted point of a handkerchief, may be 
well done by any person of usual dexterity. But it 
must always be remembered that the coverings of 
the eye are delicate, and that nothing irritating must 
be used. 
21. Sometimes a little capillary vessel in the eye is 
injured so as to cause a blight in the eye. This is 
generally not so serious as it looks, and it passes away 
in a few days. This outside care of the eye is im- 
portant, because, although there is seldom loss of sight 
from conjunctivitis, or inflammation of the coverings of 
the eye, the usefulness of the organ is often greatly 
impaired by it. 
The eye is sometimes drawn away from its natural 
position by an affection known as squint, or a cast in 
the eye. In squinting, the axes of the eyes do not con- 
verge equally toward the object viewed. There is an 
irregular action of the muscles of the eye, or a con- 
firmed failure on the part of one or the other of them 
to do its whole work. While sometimes resulting from 
disease, squinting may occur from habit. Where any 
tendency thereto is perceived, the eyes can be exercised 
by using one at a time, and looking with it in a direc- 
tion opposite to that toward which it inclines, or using 
the affected eye a little from time to time, with the 
finger extended over the nose as an additional septum. 
22. The affection which is most common in early life, 
and which is too often promoted by study and habits 
of school life, is myopia, otherwise called short-sight or 
near-sightedness. It is an over convergence of the rays 
of light, so that, being too much bent or refracted, the The Sense of Vision. 
367 
rays unite before reaching the retina, and so come to 
it overcrossed. It may here be said of all diseases or 
disabilities of the eye not superficial, and so not recog- 
nized to their full extent by the casual observer, that 
they often account for failures in study, and what is 
regarded as dullness of perception in pupils. It is the 
experience of oculists, that school-boys and school-girls 
who come to them with eye troubles, on being ques- 
tioned, confess to having been much scolded for imper- 
fect lessons or stupidity. 
Myopia, or short sight, is much more an acquired 
than an hereditary disability. Among the causes recog- 
nized are: 
(a) Bad light; (b) bad form or size of type, poor 
printing, or paper bad as to quality or color; (c) im- 
proper positions in study; (d) bad ventilation or heat- 
ing ; (e) overwork, or whatever tends to congestion 
about the head; (/) neglect of exercise for the body 
as a whole. 
The limits of a normal or healthy vision have been 
quite accurately determined. The test-types of Dr. 
Snellan are those generally adopted by oculists. A 
few of them are here given. The figures over the 
letters indicate the distance at which they will be 
distinct to the normal eye. 
Variations from normal vision may be recorded by 
using the numerals given as denominators and the 
distance in feet at which the letters are clearly seen 
as numerators; thus, if letters which should be legible 
at 10 feet can only be clearly perceived at 5 feet, 
vision = 368 
Hygiene. 
1 ft. 8i in. 
SLAHOTEUDC 
2 ft. 6 in. 
TSODHCULFE 
3 ft. 3h in. 
FOECHSUTDL 
4 ft. 6 in. 
ECLSUTFDOH 
6 ft. 1J in. 
SLFDCEUHTO 
7 ft. 
DFSELUHCTO 
9 ft. 
THDFSDUOLHEC 
10 ft. 1£ inches. 
ECHDLUTOFS 
The following words represent well-known sizes of 
types: 
Pearl. Agate. Minion. Brevier. Long Primer. 
Whilst dying embers through the room 
Small Pica. Pica. Great Primer. Double Pica. 
teach light to counterfeit a gloom The Sense of Vision. 
369 
Pica type should be used in teaching children to 
read, and is the best for ordinary reading. 
We quote as follows from Dr. Andrews: — 
23. “The reason why myopia is not unfrequently 
produced in school life can be easily conceived when 
we remember to how many of the influences above 
referred to, the eye of the child may be subjected. 
“The near-sighted eye is one which has too great 
a diameter from front to rear. The result is that the 
rays of light from objects which should be brought 
to a focus upon the retina at the back part of the eye 
come to a focus from objects at a point nearer the front 
of the eye. If the light is thus focalized before reaching 
the retina, there is a diffused or indistinct image for 
which the person seeks, to make up by a nearer ap- 
proach of the eye. This adds an additional evil by 
a greater exclusion of light. 
“In early life the tissues are soft. Some eyes are 
believed to have a more yielding or plastic tissue than 
others. The extensible, sclerotic coat becomes stretched. 
The yielding occurs most at the rear of the eyeball, 
which thus becomes elongated. So the retina is moved 
behind the best locality for focalizing. No doubt this 
exists sometimes as an inheritance or an anatomical 
defect. But far oftener it is a yielding caused by the 
improper use of the eye. 
“The act of accommodation of the eye is, by nature, 
one of slight but of healthy tension. But if constantly 
overdrawn, or if the tissue of the eye is flabby or not 
sufficiently resistant, the form is changed so as to be- 
come a serious defect. The child that uses the eye too 
early or too much in study, or with wrong type, or 370 
Hygiene. 
books, or when the general health is not good, or too 
soon after recovery from sickness, or in overheated or 
foul air, or in too great a glare or with deficiency 
of light, is too likely to give a training to the eye which 
secures for it more or less imperfection of vision. 
24. “Not to refer to the statistics of Germany, the 
facts given by Loring, Derby, Risley, and Smith, in our 
own country, show that eye defects are too common 
among our school-children. Drs. Loring and Derby, in 
examining 2,2G5 children in New York City between 
the ages of six and twenty-one, found, among the 
youngest, myopia in 3.5 per centum, and among those 
of older years 26.78 per centum. Dr. Risley of Phila- 
delphia, in an examination of 5,000 eyes, confirms the 
view as to the frequency of myopia, although also 
specifying other errors of refraction not included with 
these. In 400 recent examinations by Dr. Smith of 
Chicago for the Board of Education, four in every ten 
were found to have more or less myopia. Professor 
Erisman says he never knew myopia to begin after 
the fifteenth or sixteenth year. It generally occurs 
between six and sixteen years of age, and especially 
between six and twelve years. 
25. “A pupil should be able to see print plainly at 
a distance of from fourteen to sixteen inches. It is a 
mistake that short sight improves with advancing 
years, for although there is, for other reasons, not so 
early a need of spectacles for far sight, there is a weak- 
ening of the posterior eye which subjects it to more 
accidents after middle life. So Carter says, “ Every 
myopic eye should be looked upon as a weak organ, 
capable indeed of being preserved in a state of useful- Tiie Sense of Vision. 
371 
ness, but liable to many dangers and mischances.” 
Where there is this defect, bi-concave spectacles should 
be worn, the weakest glass being chosen with which the 
child can see comfortably. At the same time, effort 
should be made to overcome the evil, by securing con- 
ditions unfavorable to myopia, and by using the eyes 
briefly without glasses as soon as it can be done without 
inconvenience, and so soon as a right distance of the 
book is not found to fatigue, or to give indistinctness. 
“It is a great error, because it is wise to resort to 
glasses, to conclude that all the exciting causes which 
produced the myopia are to be continued. While we 
fully recognize the glasses to be the less of two evils, 
they are not the least, if we accept them as an entire 
substitute and retain other conditions promotive of 
myopia. The object of spectacles is not to make the 
patient see any better, but to compel him to keep his 
work farther away. 
26. Astigmatism is that condition of the eye in which 
all lines running in a given direction look blurred. 
It has to do with a difference in the curvature of the 
cornea in two different meridians. It is especially 
when this is different in the two eyes that attention 
is drawn to it. The correction is made by the use of 
spectacles having piano-cylindrical lenses. The effects 
of astigmatism are thus stated by Dr. R. B. Carter: — 
“The influence of astigmatism upon the sight is 
very considerable, and is exerted in various ways. Its 
first and most obvious effect is to produce differences 
in the apparent distinctness of equal lines which are 
drawn in different directions, and in this way it pro- 
duces indistinctness of some of the linear boundaries 372 
Hygiene. 
of figures, leaving others clearly defined. Thus, an 
astigmatic person, in reading a printed page, may be 
able to see clearly the printed lines which enter into 
the formation of many letters, and also, for example, 
distinguish an m from an n. But he would have to 
place the page at a different distance, or to alter the 
accommodation of his eyes, in order to distinguish the 
horizontal lines with equal clearness, and to tell readily 
an n from u. 
The indistinctness of many boundary lines produces 
a corresponding diminution in the acuteness of vision, 
and the necessity constantly to alter the adjustment in 
looking at the same object produces great fatigue of 
the ciliary muscles. Hence defective sight, coupled with 
weariness and aching of the eyes, are the symptoms 
of which astigmatic people most commonly complain. 
These symptoms, which may be kept in comparative 
abeyance, while the accommodation is strong and active, 
tend constantly to increase and to become every year 
more irksome as the accommodation is curtailed by 
advancing life.” 
27. In the chapter as to the School and its Appoint- 
ments we have already spoken of light in its relation to 
school-work. A child’s eye will not bear the continu- 
ous use which older eyes, whose tissue is firm, and whose 
powers have been developed by habit, may well endure. 
Children should not be permitted to read in the 
evening without good and abundant light. The book 
should be so placed relatively to the light and the face, 
that the angle of incidence shall differ from that formed 
by the book and the eye. The light should never be 
directly in front of the face. It may be a little to the The Sense of Vision. 
373 
left, and in front, but it is better to have it above and 
behind the head. 
No child should be permitted to lie on the floor to 
study a lesson or read. Especially is this injurious 
when done before a burning grate. In a recumbent 
position the strain on the inferior rectus muscle of the 
eye, or that which moves the eye downward, is very 
great. The hours given to reading or studying in the 
evening should be short. The healthy child, who has 
risen at seven in the morning, and pursued the proper 
course of study in school through the day, is in no 
condition, mentally or physically, to resume them 
again at seven in the evening. If it be necessary, let 
the evening study be limited to one hour. 
28. It is well in reading to interrupt the strain of 
continuous gaze upon the page, and rest the eyes, by 
looking into the distance occasionally, even if only for 
a few seconds. In studying, or in reading anything 
that requires thought, this is likely to be done uncon- 
sciously ; the natural condition in close thought is rest 
of everything except the brain. 
As distant vision represents rest for the eyes, and 
near vision represents exertion, care should be taken in 
reading not unnecessarily to increase this exertion by 
holding the book too close. The book should not be 
held nearer to the eyes than is necessary to make the 
print appear perfectly sharp and distinct, and no print 
should be read continuously that cannot be seen clearly 
at about fifteen inches. 
29. In reading while lying down it is hardly possible 
to hold the book in a favorable position, and the external 
muscles of the eye are strained. In addition to this, 374 
Hygiene. 
when the head is on a level with the body, instead of 
erect, there is a tendency to an excess of blood in the 
eyes. 
“ It is not well to persist in reading when overcome 
with sleep, as there is a constant tendency for the 
muscles of accommodation to relax, and of the eyes to 
diverge, and they have to be forced back to their work 
by an effort of the will. The effect of this is soon shown 
in a congestion of the blood-vessels of the conjunctiva 
or white of the eye. ” 
30. Of all the artificial lights, that of an Argand 
burner is the best, because of its steadiness. That 
from a good kerosene lamp is next. Candles and the 
ordinary gas-jets are objectionable, because of flicker- 
ing; of the latter, the so-called fish-tail burner gives 
the steadiest flame. 
Thus far, care and prevention have applied to the 
school-room. Too few homes have well-lighted rooms 
day or night. Even where there are large areas of plate 
and crystal glass, curtaihs, lambrequins, and shutters 
are used to exclude sunlight in the dwellings of the 
rich; small windows, low rooms, obstructing buildings, 
and narrow alleys darken the abodes of the poor. 
The reading of children at home is often done under 
unfavorable circumstances. Examine the books which 
come from the library, the story-papers, the novels, the 
magazines, and the long list of small-type literature. 
Watch the children, and see the enormous strain they 
put upon accommodation muscles of the eye to read 
the abominable print. Compare this with the clear fine 
face of long primer or pica. The hygienic principles 
applied to books in school should be enforced in home 
reading. The Sense of Vision. 
375 
The following directions of Dr. Lincoln of Boston 
are of value: — 
31. “ When writing, reading, drawing, sewing, always 
take care that, (a) the room is comfortably cool, and 
the feet warm; (6) there is nothing tight about the 
neck; (c) there is plenty of light, without dazzling 
the eyes; (d) the sun does not shine directly upon 
the object you are at work upon, or upon objects in 
front of you; (e) the light does not come from in 
front; it is best when it comes over the left shoulder; 
(/) the head is not bent very much over the work; 
(g) the page is nearly perpendicular to the line of 
sight; that is, that the line of the eye is nearly oppo- 
site the middle of the page, for an object held slanting 
is not seen so clearly; (h) that the page or other object 
is not less than fifteen inches from the eye; (i) in any 
case where the eyes have any defect, fine needlework, 
drawing of fine maps, and all such work, except for very 
short tasks in the morning, (j) In addition, never 
study or write before breakfast by lamplight; (k) do not 
lie down when reading; (l) if your eyes are aching 
from firelight, from looking at the snow, from over- 
work or other causes, a pair of colored glasses may 
be advised to be used for a while; (m) never play 
tricks with the eyes, as squinting or rolling them, (n) 
The eyes are often troublesome when the stomach is 
out of order. (o) Avoid reading or sewing by twilight, 
or when debilitated by recent illness, especially fever. 
(p) It is indispensable in all forms of labor requiring 
the exercise of vision on minute objects, that the worker 
should rise from his task now and then, take a few 
deep inspirations with closed mouth; stretch the frame 376 
Hygiene. 
out into the most erect posture, throw the arms back- 
ward. and forward, and if possible step to a window, or 
into the open air, if only for a moment.” 
32. While the chief danger to children is from myopia, 
or short-sight, there are occasionally children that are 
hypermetropic, or too long-sighted. “ Flat-eye ” is another 
name for it. Fatigue, pain, and indistinct vision, after 
any long reading or study, will be generally complained 
of. The child does not relieve it by holding the book 
at a distance, but soon complains again. Headaches 
and convergent squinting may result from it. Here, 
convex glasses are needed. 
Where much reading or writing is done at night, 
it is well to use a shade over the study-light, so that 
the light is cast more directly on the paper or book. 
33. Persons who see well, and yet are defective in per- 
ceiving distinctions of colors, are said to be color-blind. 
This inability is most marked as to red, green, and violet, 
or blue and violet, which are called the primary colors 
of the spectrum. Being unable to see these they thus see 
all colors modified as they would be by their absence. 
The defect varies greatly in degree. A large proportion 
of the color-blind are so in reference to red, next as to 
green, but comparatively few are violet-blind. A person 
who is red-blind cannot distinguish red from green. If 
blind to violet he cannot tell that from yellow. Because 
systems of color signals, both for ship and railroads, are 
so indispensable, it is now common to examine employees 
as to powers of discerning colors. The usual test is the 
Holmgren test, which consists in the use of worsteds of 
various colors. The person being examined does not name 
the colors, but having a sample of each selects and The Sense of Vision. 
377 
places each in its appropriate bunch. Examinations 
show, among men at least, one out of every fifty defective, 
and many to a degree that unfits them for any service 
requiring accuracy in the perception of colors. The 
defect is often congenital, but is also known to be caused 
by alcohol or tobacco, and by some forms of mental 
disease. 
34. There are other forms of visual defect, but these 
are generally so declarative as to excite attention and lead 
to the seeking of professional advice. As any defect in 
vision is a serious interference with the work of life, 
the eye is to be looked upon as the chief instrument 
of the student, the mechanic, the artisan, the laborer of 
every kind. As such, it is to be guarded and kept as 
would be the most essential and delicate tools used in 
any occupation. To do the best of work with it, it 
must he kept in the best of order. 
It is because this is true to a greater or less extent 
of every organ, and of the whole body, that the teaching 
and practice of Hygiene are essential parts of educa- 
tion. INDEX. 
PAGE 
Carbonic Oxide .... 252, 256 
Catsups 241 
Cerebro-Spinal System . . . 308 
Cereals 206, 229 
Cesspools 299 
Chemical Tests of Water . . 50 
Cigarettes 244 
Circulation of the Blood, 147, 153 
Cisterns 40 
Climate 29, 63, 77 
Clothing ... 79, 130-146, 246 
Colds Ill, 337 
Color of Clothing 132 
Combustion 252 
Composition of the Blood . . 150 
Condiments 193, 238 
Conduction 129, 249 
Conjunctiva, The 365 
Convection 129, 248 
Coffee, Tea, and Cocoa . . . 225 
Cookery 216 
Corns and Bunions .... 119 
Cowls 263 
Curry Powders 241 
Deep Wells 43, 47 
Deformities 88 - 93, 97 
Department of Hygiene ... 21 
Design 18 
PAGE 
Aerated Water 36, 61 
Air, 25, 63-66, 72, 144, 152, 164, 169, 
176, 251 
Air Cells 163 
“ Space 272 
Albuminoids 185 
Alcohol, 153, 186, 194, 229-238, 242, 
323, 335, 377 
Alimentary Canal 178 
Ammonia 64 
Anatomy 15, 80 
Animal Life 25 
Astigmatism 371 
Athletics 104 
Atmosphere 265 
Bacteria 38 
Bad Clothing 143 
Bathing 103 
Biology 15 
Blight of Eye 366 
Blood, The 147, 164 
“ Hygiene of 157 
Bones 80, 87 
Bread 221 
Bronchia 170 
Calisthenics 106 
Carbonic Acid 63, 266 
379 380 
Index. 
TAGE 
Diaphragm, The . . . 166, 191 
Digestion 178 
Diseases in Schools .... 295 
Disinfectants 304 
Drainage ■ 27 
Draught 71, 270 
Drinking-water 35 
Drinks ... 225 
Duct, Thoracic 155 
Ear, The 339 
Earache 348 
Earth, The 24, 34 
Eating 191 
Education 20, 325 
Electricity 76 
Evaporation 129, 131 
Exercise 98, 156 
Eye, The 296, 350 
Eyebrows 350 
Faintness 157 
Filters and Filtration . . 53, 56 
Fireplaces 249 
Foods 186, 196 
Frictions of the Skin .... 128 
Furnaces 249 
Gases 25, 265, 286 
Gases of the Blood .... 151 
Gas-lighting 286 
Galton Grate 258 
Glands . . . .110, 180, 181, 188 
Ground Water 32 
Gymnastics 104 
Habitations 143 
Hair, The 120 
Hardness of Water . . .59, 128 
Head Covering 136 
PAGE 
Health of Skin 124 
Hearing ......... 338 
Heat 30, 76, 148, 191 
Heating 246 
Hot Air Heating 257 
Hot Water Heating .... 257 
House and Cistern Filters . . 56 
House Plants 64 
Humors of the Eye .... 357 
Hygiene of Bones 87 
Hygiology 13 
Hyperinetropia 376 
Ice Water 62 
Impurities of Air . . . .65, 272 
Indirect Radiation ..... 261 
Iris, The 354 
Laryngitis 174 
Lead Pipes 52 
Ligaments and Tendons . . 96 
Light 63, 74, 76, 268 
Liver, The 91, 191 
Lung Hemorrhage 158 
Lungs, The 159 
Lymphatic Vessels . 116, 123, 155 
Meats 202, 211 
Mesentery, The 189 
Microbia 38 
Microphytes 38 
Milk 209 
Minerals 24 
Moisture in Air . . 64, 72, 254, 300 
Molars, Sixth Year .... 183 
Mouth Breathing . . . 169, 175 
Muscles, The .... 94, 166, 342 
Muscles of the Eye .... 357 
Muscular Sense 330 
Myopia 366 Index. 
381 
PAGE 
Nails, The 120 
Narcotics 231, 238 
Nervous Diseases 322 
Nervous System 307 
Nitrogen 63, 266 
Nose-bleed 358 
Odors 337 
Oiling of Skin 103 
Oil Glands 115 
Opium 323 
Overwork 324 
Oxygen 63, 266 
Ozone 64, 266 
Parasites 38 
Pathology 16 
Pepper 240 
Personal Hygiene 23 
Physician 14 
Physiology and Anatomy . . 15 
Plants and Flowers in Rooms 64 
Plates of Skeleton . . . 83-85 
Posture . 88, 168 
Potable Water 35 
Pressure ... 90, 92, 156, 190 
Profile of Skeleton 81 
Psychology 17 
Purity of Air .... 67, 72, 284 
Purity of Water 48 
Radiation 129, 249, 250 
Radiators 249 
Rainfall 46 
Rainwater 39 
Reflex Nervous Action . . . 319 
Refuse 299 
Reservoir 44 
Respiration 165 
Retina, The . . . . . 356, 360 
River and Lake Water ... 44 
PAGE 
Sanitation, Sanitary Science . 16 
Saturation of Air . . . .64, 263 
School-houses 289 
Schools 251, 289 
Sensations 329 
Senses, The 328 
Sewerage 37 
Shallow Wells 42, 46 
Sickness a Breach of Law . . 14 
Sight 350, 359 
Skeleton, in Profile .... 81 
Skin, The 109, 333 
Smell 336 
Soap 60 
Soil 30 
Sore-tliroat 296, 347 
Specks in the Eye 365 
Spinal Curvature 167 
Spleen, The 155 
Springs 42 
Squint 366 
Stagnant Air and Water . . 26 
Steam Heating 258 
Stimulants, 153, 154,194,229-238,242 
Stomach, The 180 
Stoves 250 
Sty 351, 363 
Study of Hygiene, Beasons for 20 
Sugars 215 
Sun-baths 75 
Sun-heat 63 
Surface Water 41 
Sweat Glands 110 
Sympathetic Nervous System, 310,317 
Tables of Foods 205 
Tears 351 
Teeth The 182, 185 
Temperature 192, 254 
Tests of Air 284 382 
Index. 
PAGE 
Tests of Purity of Water . . 48 
Thermometers 254 
Thoracic Duct 155 
Tobacco, 194, 242 - 245, 323, 325, 377 
Touch, Sense of 332 
Tube Wells 48 
Types for Testing Eyes . . . 368 
Uses of the Skin 121 
Vaso-motor Nerves 157 
Vegetable Life 25, 38 
PAGE 
Vegetables 214, 223 
Ventilators 277, 230 
Voice, The 171 
Walking 103 
Water 34, 112, 115 
Water, Boiled . . . 60, 61, 217 
Water Gas 287 
Water-proof Clothing .... 142 
Wells 42 
Wounds 158 
Note. — As all technical terms used are explained in the text, or can 
be found in the general Dictionaries, it has not been deemed necessary to 
add a Glossary.