DERS BY WILLIAM M. POWELL, M. D.. Ilttendlng Physician to the Mercer House for Invalid Women, at Atlantic COffc Wx- K. J.; Late Physician Jppthe work of preparing Students’ Manuals Is to end we cannot say, ■paanderaseries, in our opinion, bears off the palm at present.” Mtty Medical Magazine Best of their class that have yet appeared,” fftt California Practitioner Jpunders’sefies of Com pends are the besteverpublishedin this country.”'** *pt<—EISSENTIAL8 OF PHYSIOLOGY. Third edition. Finely illustrated K Revised and greatly enlarged by H. A. Hare, M.D. (Price, $i.00, net.) J|»;2.—ESSENTIALS OF SURGERY. With Appendix on Antiseptics. Fourth edition. 90 illustrations. By Edward Martin, M D. ip. 3.—ESSENTIALS OF ANATOMY. Based on Gray. Fourth edition. 180 illustrations. By Charles B. Nancrede, M.D. ■fo,4.—ESSENTIALS OF MEDICAL CHEMISTRY, ORGANIC AND INOR- GANIC. Third Revised edition. With an Appendix By Lawrence E Wolff, M.U. mo. 5.—ESSENTIALS OF OBSTETRICS. Third edition. Revised and greatly ■fe enlarged. 73 illustrations. By W. Easterly Ashton, M.D. Jr©, ft—ESSENTIALS OF PATHOLOGY AND MORBID ANATOMY. Fourth Br, thousand. 46 illustrations. By C. E. Armand Semple, M.D. HU ESSENTIALS OF MATERIA MEDICA. Therapeutic and Perscription B&- Writing. Second edition. Sixth thousand. By Henry Morris, M.D, Bgfos. 8 and 9.—ESSENTIALS OF PRACTICE OF MEDICINE. By Henry Morris, M.D. And an Appendix on Urine Examination. Illustrated. By Lawrence Wolfe, M. L). Second edition, enlarged by some. 300 Eeaenr ■K j tial Formulae, selected from eminent authorities, by Wii. M. Powell, ■K*..' M.D. (Double number, price, $2.00) M»o. 10.—ESSENTIALS OF GYNAECOLOGY. With 68 illustrations. Second edition. By Edwin B. Cragin, M.D. mjfo. 11.—ESSENTIALS OF DISEASES OF THE SKIN. Second edition. 75 BBB” Illustrations. By Henry W. 8tblwagon, M.D. m-.Ho. 13-ESSENTIALS OF MINOR SURGERY BANDAGING AND VENE* flp:- REAL DISEASES. 82 illustrations. By Edward Martin, M.D. INESSENTIALS OF LEGAL MEDICINE, TOXICOLOGY AND HY- K; G1ENE. 130 illustrations. By C. E. Armand Semple, M.D jP No. 14.—ESSENTIALS OF DISEASES OF THE EYE, NOSE AND THROAT. ER% 118 illustrations. By Edward Jackson, M.D., and E. Baldwin Gleason, E* M.D. E NO, 15.—ESSENTIALS OF DISEASES OF CHILDREN. By William M. Pow- 'h. ELL, M.D. V No. 16 —ESSENTIALS OF EXAMINATION OP URINE. Colored “Vogel Scale,” and numerous illustrations. By Lawrence Wolff, M.D. (Price, f 75 cents.) fc>No. 17—ESSENTIALS OF DIAGNOSIS. By S. Bolib-Cohkn M.D. and A. A K .... Gohner, M.D. 55 illustrations (some of which are colored), and a frontis- ei, piece. (Price, $1.50, net,) ■f No. 18-ESSENTIALS OF PRACTICE OF PHARMACY. By L. E. Sayre. ' ; No, 19—ESSENTIALS OF HYGIENE. Illustrated, By Robert P. Robin M.D. (Preparing.) II No. 20—ESSENTIALS OF BACTERIOLOGY. 77 Illustrations (sOitfk colon p, .- By M. V. Ball, M.D . * te No. 21—ESSENTIALS OF NERVOUS DISEASES AND INSANITY. 48 orfg; ' Illustrations. By Johw C. Shaw, M.D. &No. 22—ESSENTIALS OF MEDICAL PHYSICS. 15-i illustrations. By M BifflK, ■ J. Brockway, M. V. (Price, $1.00, net.) SaNo. 28—ESSENTIALS OF MEDICAL ELECTRICITY. 65 Ulus',ration David D. Stewart, M.D. and Edward S. La whence, M.D. SAUNDERS’ QUESTION-COMPENDS. No. T ESSENTIALS OK MEDICAL CHEMISTRY, ORGANIC AND INORGANIC, CONTAINING ALSO QUESTIONS OF MEDICAL PHYSICS, CHEMICAL PHILOSOPHY, ANALYTICAL PROCESSES, TOXICOLOGY, ETC., PREPARED ESPECIALLY FOR STUDENTS OF MEDICINE, BY LAWRENCE WOLFF, M. D., DEMONSTRATOR OF CHEMISTRY, JEFFERSON MEDICAL COLLEGE; PHYSICIAN TO TIIH GER- MAN HOSPITAL, OF PHILADELPHIA ; MEMBER OF THE GERMAN CHEMICAL SOCIETY, OF THE PHILADELPHIA COLLEGE OF PHARMACY, ETC. THIRD AND REVISED EDITION, WITH AN APPENDIX. PHILADELPHIA w. B. SAUNDE IT&V 913 Walnut Strk.et. 1893. Copyright, 1888—1891. By W. B. SAUNDERS. TO J. W. HOLLAND, M.D., PROFESSOR OF MEDICAL CHEMISTRY AND TOXICOLOGY, JEFFERSON MEDICAL COLLEGE OF PHILADELPHIA, WHO KINDLY ENCOURAGED THE WRITER IN THE PREPARATION OF THIS LITTLE WORK, AND BEFRIENDED HIM IN MANY OTHER WAYS, iolflnu IS GRATEFULLY INSCRIBED BY THE AUTHOR. PREFACE TO THE THIRD EDITION. The call for a third edition of this little book, after two editions of two thousand copies of each have been ex- hausted within three years, is certainly gratifying to the author, and assures him that his aim to present it as an aid to the medical student in his pursuit of chemistry has been realized. He thinks that this compend has riot interfered with more thorough reading from text-books, but has helped to make these better understood, and has thus rendered the path of the medical student in this direction less difficult. It was not found necessary materially to enlarge the sub- ject in this edition. But the text has been carefully gone over. A few errors were corrected, and several tables, of the elements, weights and measures with rules for convert- ing them, thermometric scales, etc., were appended. Trusting that this issue will have the same generous re- ception from all parts of the country which has been accorded to the former editions, the author hopes that it will be a welcome friend to the student, which will help him better to appreciate the subject under consideration, and in doing so extend his usefulness as a medical practitioner. L. W. August, 1891. V PREFACE TO THE FIRST EDITION. An extensive experience in preparing medical students for examination in Chemistry has satisfied the writer that the incomplete knowledge of this department of medical science, so often exhibited by students and physicians, is generally due to their inability to study the subject thoroughly with- out encroaching in too great a degree on the time required for the more practical branches of their profession. Most students appear to be justified in claiming that they have derived much profit from the systematic course of “ quizzing” which is in vogue at the medical schools. This benefit is attributable, no doubt, to the fact that by this mode of instruction essential points are brought out in the form of questions which exact attentive consideration before adequate answers to them can be given. In the volume here presented the author has the same object in view, and while he trusts that it will not be the means of dispensing with the deeper study of the subject, he feels assured that unless the frame-work of knowledge be first well constructed, substantial progress will be quite impossible. If this little work shall tend to give students a better understanding of Chemistry, and with it a greater love, or perhaps less of a distaste, for the pursuit in connection with their medical studies, the writer considers that he will have achieved much of that which he attempted. VII VIII PREFACE. As an introductory course to Chemistry in most, if not in all, medical colleges includes the principles of Physics, some essential questions on this subject precede the chemi- cal part of the work. Theoretical Chemistry, though treated in a separate chapter, is also frequently referred to through- out the text. The classification of the elements is some- what at variance with the most modern ideas of pure Chemistry, but it has been given with the view of pre- senting the matter in logical sequence to the medical mind. Toxicology has received ample consideration under the head of each element or compound which possesses markedly poisonous properties. Analytical processes have been brought out as far as compatible with the condensation of so large a subject within so limited a space. No separate chapter or part is devoted to the “ urine and its analysis,” its components being considered in the order of their pre- cedence in the adopted arrangement. The questions and answers of this Manual have been so arranged as to conform to the principal text-books on the subject. For this purpose the authoritative works of Fownes, Attfield, Richter, Charles, Barker, and Witthaus, as well as Holland on the Urine, and Draper and Ganot on Physics, have been freely used in its preparation. L. W. Philadelphia, Pa., 333 South Twelfth St. August, 1888. CONTENTS. PHYSICS. Weights, measures, and specific gravity .... 17 Ileat—thermometers 20 Magnetism .25 Electricity .28 PA«e CHEMISTRY. Theoretical chemistry 40 Hydrogen 50 Oxygen 52 Ozone . . • 54 Water 55 Electronegative monads—halogens 60 Chlorine . . . 61 Bromine 65 Iodine .66 Fluorine 66 Electronegative dyads 67 Sulphur . . .67 Electronegative triads or nitrogen group .... 72 Nitrogen 72 Phosphorus 76 Arsenic 80 Antimony 87 Boron group 89 Boron 89 IX X CONTENTS. PAGE Electronegative tetrads or carbon group . . . .90 Carbon 90 Silicon 98 Metals of the alkalies 99 Potassium 99 Sodium 104 Lithium 109 Ammonium 109 Metals of the alkaline earths Ill Calcium Ill Barium 115 Magnesium group 110 Magnesium 110 Zinc 118 Lead group < 119 Lead 119 Copper group 124 Copper 124 Mercury 127 Silver 132 Aluminium group 133 Aluminium 133 Iron group 134 Manganese 134 Iron 135 Nickel 140 Chromium group 140 Chromium 140 Uranium 141 Tin group . 141 Tin 141 Bismuth group . 142 Bismuth 142 CONTENTS. XI PAGE Platinum group 144 Gold .144 Platinum 145 Hydrocarbons and derivatives 146 Saturated hydrocarbons 146 Alcohols 151 Ethers 155 Aldehydes . . .159 Monobasic acids 161 Carbohydrates .175 Glucosides 183 Substituted ammonias . 185 Alkaloids 191 Proteids . 198 Coloring bodies 202 ESSENTIALS OF MEDICAL CHEMISTRY. PHYSICS. Weights, Measures, and Specific Gravity. What is weight? The amount of force necessary to neutralize the attraction of the earth upon a body. State the different kinds of weight. Apparent, absolute, and specific. Define these three. Apparent weight is that of a body in the air; absolute that in vacuo; specific, the relative weight of a body in comparison with that of the same volume of some other medium. Which system of weights and measures is employed in chemistry and chemical operations ? The Trench or metric system based upon the metre as unit. Give the subdivisions of a metre. It is subdivided into 10 decimetres, 100 centimetres, 1000 milli- metres. What are the terms for decimal multiples of the metre ? 10 metres equal to one dekametre. 100 metres equal to one hektometre. 1000 metres equal to one kilometre. State the unit of fluid measure of the metric system. The cube of one centimetre or one cubic centimetre, usually abbreviated as 1 c.c. How much is one litre ? 1000 cubic centimetres. 18 ESSENTIALS OF MEDICAL CHEMISTRY. Give the unit of metric weight. One gram, equal to 15.432 grains. How is the gram derived? From a cubic centimetre of distilled water at its maximum density (+ 4° C.). What are the decimal subdivisions of a gram ? 1 gram=10 decigrams=100 centigrams=1000 milligrams. How are the decimal multiples of a gram designate! ? By Greek numerals. 10 grams = 1 dekagram ; 100 grams = 1 hektogram ; 1000 grams = 1 kilogram. Give the equivalents in Troy weight of 1 gram, 1 kilogram, also in grams of 1 grain and 1 oz. Troy. 1 gram = 15.434 grains; 1 kilogram = 2.679 lbs. Troy; 1 grain = 0.065 grams ; 1 oz. Troy = 31.103 grains. What are scales and balances ? Instruments to determine the weights of bodies. State what chemical balances are, and their principal parts. Instruments indicating at least one milligram, having knife edges on which the beams and hangers are equipoised. How are chemical balances steadied, and how should they be kept? They are steadied by rests to keep them in a state of repose; they should be well levelled on a solid foundation in glass cases to prevent the influences of draughts of air, weather, heat, dust, etc. By what means are minute differences of weight determined ? By riders placed on notches on the beam. When a body is weighed in air and then in water, where is it the heaviest ? When weighed in air. What is the loss of weight it experiences in water ? As much as the weight of the volume of water it displaces. WEIGHTS, MEASURES, ETC 19 What is its specific weight or gravity then ? The relative proportion between its weight in air and its loss of weight in water. How is the specific gravity of a body heavier than water determined ? By weighing the body first in air and then immersed in water, determining the difference between the two, and then dividing the weight in air by that difference. If a body is lighter than water how is its specific gravity obtained ? Attach it to another body heavier than water, the loss of weight of which in water has been previously ascertained. Find out the loss in water of both together and deduct the loss of the heavier one from it; the difference will be that of the lighter body alone, with which divide its weight in air. If a body is soluble in water how is its specific gravity obtained ? By immersing it in another incompatible liquid of known sp. gr., dividing with its loss therein the weight in air, and then multiplying with sp. gr. of the liquid used. State what a Pyknometer is, and how the specific gravity of liquids is ascertained with it. A specific gravity bottle having a glass stopper with a capillary opening through it, and usually of a size to contain accurately 1000 grains distilled water at 4°C. If this is well filled with the liquid to be examined, and then dried externally and placed on the scales, the increased or decreased amount of the weight of the same divided by 1000 will give its specific gravity. The weight of the bottle in this operation must be counterpoised or tarecl; the temperature of the other liquid should be at 0° C. or computed for that degree. What is the law of Archimedes ? A body immersed in water loses part of its weight equal to the weight of the displaced liquid. 20 ESSENTIALS OF MEDICAL CHEMISTRY. State the position an egg will occupy in pure water and in a saturated solution of sodium chloride, and give the reason for the same. In pure water it sinks, in saturated Na Cl solution it floats, because the liquid displaced by it in the pure water is lighter than its own weight and heavier in the Na Cl solution, thus buoying it up in the latter. What instruments are based on the above experiment, and what are they used for, and what are their names ac- cording to application? Hydrometers, used for readily ascertaining the specific gravity of liquids, called, according to their use, urinometers, alcoholo- meters, lactometers, etc. How is the scale of hydrometers arranged ? For liquids heavier than water the sp. gr. scale of hydrometers has 1000 on top and the heavier marks below; the hydrometers intended for taking the sp. gr. of lighter liquids is marked 1000 at the bottom of the scale and the lighter degrees are above. What are urinometers, and what is the extent of their scales ? Hydrometers intended for taking the sp. gr. of urine; marked from 1000 at the top to about 1060 at the bottom. How is the specific gravity of a liquid observed by a hydro- meter ? By partly filling the cylinder with the liquid to be examined, floating the instrument therein, then filling carefully to the top of the cylinder, and reading the mark over the top of the liquid. How is the quality of good hydrometers ascertained ? By immersing in various liquids of known specific gravity and comparing the marks indicated with those known of the liquids. Heat—Thermometers. What is heat ? A condition of matter manifesting itself by physical phe- nomena and convertible into other forms of force. HEAT — THERMOMETERS. 21 When two bodies of different temperature are brought in con- tact what is the result? They tend to equalize the amount of heat they are respectively possessed of. If equal quantities of water of the temperature of 100° C. and of 162° C. are mixed together what will be the tempera- ture of the mixture ? The mean of the two or 131° G. If equal quantities of water at 0° C. and mercury at 100° C. are mixed, what is the temperature of the mixture, and why? The mixture will be at 3.3° C., because the heat capacity of water is 1000 to 0.033 for mercury; i e., the water requires about 33 times as much heat as mercury to elevate it to the same tem- perature. What is the individual heat capacity of bodies termed, and how defined ? Their specific heat, or the amount of heat necessary to raise the temperature of a body one degree compared with that re- quired to raise the temperature of the same weight of water one degree. What is a calorie and what a thermal unit (English) ? The quantity of heat necessary to raise one kilogram of water through one degree centigrade is one calorie (large); that neces- sary to raise one gram through one degree centigrade is the small or chemical calorie ; that required to raise one pound of water through one degree centigrade, one thermal unit = 0.45 calorie (large) ; one large calorie = 2.2 thermal units. What is the temperature of a mixture of equal weights of water of 60° C. and of 0° C.? 30° C. What is the temperature of equal weights of water at 60° C. and ice at 0° C. ? It will remain at 0° C. until all the ice is melted. Why is this so ? Because the ice absorbs all the heat of the water to accomplish its change from the solid to the liquid state. 22 ESSENTIALS OF MEDICAL CHEMISTRY. What is the heat absorbed by bodies in their change of state, not indicated by the thermometer, called ? Latent heat. What three states of matter are there ’ Solid, liquid, and gaseous. What is matter composed of? Molecules and interspaces. What are molecules ? The smallest physical units of matter. State the relative condition of molecules in solid, liquid, and gaseous bodies. In solids, the relative positions of the molecules are fixed, and cannot be changed without the expenditure of more or less force. In liquids, the relative positions of the molecules are not fixed, they glide past each other coherently, while in gaseous bodies the molecules repel each other, and tend to occupy larger spaces. If a metal ball fitting closely into a ring be heated and then placed in the ring, what is the result ? It will no longer pass through it until it again returns to its ordinary temperature. What can be said to be the effect of heat on bodies, and what on different forms of matter ? They are expanded by increase of temperature, and contracted by its decrease. The expansion in solids is small, in liquids greater, and for gases the greatest. As matter is composed of molecules and interspaces, which of the two are thus expanded by heat ? The interspaces, as the molecule is a unit, and cannot increase or decrease in size. What is a thermoscope ? A glass bulb containing air connected with a narrow tube con- taining a liquid. Very slight variations of temperature are in- dicated thus by a change of position of the liquid. H E A T — TH ERMO METERS. 23 If a bulb of alcohol or mercury or other liquid, to which is attached a narrow tube, is heated, what is the result ? The liquid ascends in the tube. What are thermometers? Instruments for measuring temperature. How are they constructed? They consist of a bulb of liquid attached to a closed and air- less capillary tube ; this latter is graduated to indicate the de- grees of temperature. What thermometers are principally used, which preferably, and why ? Alcohol and mercury thermometers ; the latter preferably, because the mercury does not wet the glass tube, and does not boil so readily as alcohol. When are alcohol thermometers to be preferred ? To measure very low degrees of temperature when mercury would freeze. Which are the principal scales of the thermometer in use ? Fahrenheit and Centigrade (Reaumur also). How is the Fahrenheit scale graduated ? It is divided into 212 equal divisions or degrees, the lowest of which is a mixture of equal parts of sal-ammonia and snow, and the highest the boiling point of pure water; the freezing point of water on this scale is 32°. How is the Centigrade scale graduated ? By division into 100 equal parts or degrees, the space of expan- sion from the freezing point to the boiling point of pure water. Which is commonly used, and which in chemistry ? The Fahrenheit scale is in common use in this country, the Centigrade scale in chemistry. How are degrees of Centigrade scale converted into those of Fahrenheit? As the number of degrees between the boiling and freezing 24 ESSENTIALS OF MEDICAL CHEMISTRY. point of water in Centigrade is 100 and in Fahrenheit 212 — 32 = 180, the proportion would be 100 :180 degree to be converted: x by division with 20 it would read 5 :9-i-cent.: x i. e., the degree to be converted is multiplied with 9, the result divided by 5, and 32 added to the result, as per following formula : Cent; X 9 + 32 = Fahr. 5 How are degrees of Fahrenheit converted into Centigrade? From the degree to be converted 32 is subtracted, the differ- ence is divided by 9, and the quotient multiplied by 5, as per following formula : —— X 5 = Centigrade. What are clinical thermometers, and what their range? Thermometers for determining the temperature of the body. Their scale ranges usually from 90°-110° F. What are self-registering thermometers, and what are inde- structible registeis? Thermometers which have a small separate column of mer- cury, which is shoved up by expansion, but does not contract with the main column, are called self-registering. If these regis- ters are so arranged that they cannot slip down, or be shaken down into the bulb, they are called indestructible. Why are new thermometers usually incorrect, and what should be done with them? On account of the contraction of the glass going on for some years, they should for that reason be seasoned at least three years before being marked. How are thermometers standardized? They are compared, at their different degrees, with other in- struments known to be correct. MAGNETISM. 25 MAGNETISM. What is magnetism ? The force by which loadstone attracts iron. Give the chemical name and composition of loadstone. Magnetic oxide of iron : Fe304 = Fe0.Fe203 = Ferrous-ferric oxide. Describe natural, temporary, and permanent magnets. Loadstone is a natural magnet. Soft iron, in which magnet- ism is induced, is a temporary magnet. Steel, when magnetized, becomes a permanent, artificial magnet. What are magnetic poles and what neutral lines? The ends of magnetic bars are termed their poles ; the middle line between them, which has no power of attraction, is their neutral line. State what the magnetic axis is. The shortest lines between the poles. Which is the north pole and which is the south pole of a magnet in this country ? The pole pointing to the north is the north pole, that pointing to the south the south pole ; in France and China the reverse terms are in use. When particles of soft iron are in contact or influenced by a magnet, what do they become in turn ? Temporary magnets. Give the action of a magnet on iron filings. They become, each particle, magnets of more or less strength, and consequently arrange themselves into tufts. What is magnetic induction? The production of magnetism in other substances either by direct or indirect contact. Can magnetism be induced by contact only? No, it may even act through different media, such as glass, wood, paper, etc. 26 ESSENTIALS OF MEDICAL CHEMISTRY. Does iron alone show magnetic polarity? Its compounds also, as well as those of nickel and cobalt, give evidence of it. If a magnet is broken in two or into many pieces, what is the magnetic condition of each piece ? Each piece is a distinct magnet with different poles, as one kind of polarity cannot exist without the other. What is the hypothesis of magnetism ? That each molecule of a magnet shows magnetic polarity. If a magnet is evenly balanced or suspended in the middle what position does it assume ? It places itself in the direction of the magnetic poles of the earth. About what distance are the terrestrial magnetic poles from the true poles ? More or less 1000 miles, varying according to the magnetic axis. Give the meaning of declination of the magnetic needle. The angle it makes with the meridian. What instrument for orientation is based upon the north and south direction of the magnetic needle. The mariner’s compass. State the result of approaching the north end of the magnetic needle with the north pole of a magnet. The needle point is repelled, and if the north point is ap- proached by the south pole of a magnet it is attracted. What law is based upon this? Like poles repel, unlike attract. If an unmagnetized steel needle is suspended in the middle and subsequently magnetized, what occurs besides its orientation ? It dips towards the poles, increasing in this respect the nearer it approaches them. MAGNETISM . 27 What is this called ? The dip or inclination of the magnetic needle. What is a horseshoe magnet, and what is its object? A magnetic bar bent in horseshoe shape, the two poles thus acting by induction upon each other, and increasing each other’s power. What is a magnetic battery or a Germain magnet ? A series of magnetic steel plates joined with their similar poles, making the magnet very powerful. What is an armature ? » A piece of soft iron closing the space between the poles of the horseshoe magnet, intended to preserve its magnetic force, which would otherwise be gradually lost. Are other bodies besides those known as magnetic affected by magnetism ? Many bodies are so affected, especially the metals, but in much less degree than iron, nickel, and cobalt. What is paramagnetism ? The power of magnets to direct substances affected by them in an axial position, i. e., parallel with the magnetic axis; such as iron, nickel, cobalt, manganese, chromium, etc.; the substances so affected are called paramagnetic. What is diamagnetism ? The power of magnets to give certain substances, influenced by them, a direction at right angles to the magnetic axis; such as bismuth, antimony, zinc, tin, etc. These are called diamag- netic. When two magnetic bars of equal power are joined with un- like poles together what is the attracting force of the two together? They neutralize each other, and have no attracting force. What are astatic needles ? Magnetic needles placed so that the north end of the one is counteracted by the south end of the other. They lose their power of orientation. 28 ESSENTIALS OF MEDICAL CHEMISTRY. ELECTRICITY. What is Franklinism? Frictional or static electricity; a physical condition produced in certain bodies, such as glass or resins, by friction with silk, wool, or catskin. What are its principal properties ? Those of attracting small light bodies such as paper, feathers, etc., and of repelling them on contact. How is this best shown ? By an electroscope. Describe a gold-leaf electroscope. It is an instrument for detecting electricity, consisting of two strips of gold leaf suspended together at one end in a glass jar and connected through the cover with a metallic bar and knob. When the latter is touched or approached with an electrified body the two strips fly apart, because they become equally elec- trified and repel each other. What electricity is produced by the friction of glass? Vitreous or positive electricity. What from resins ? Resinous or negative electricity. What are conductors, and what are non-conductors of elec- tricity ? Bodies conveying it are conductors; bodies not capable of con- veying it are non-conductors. What is the law of conductivity? Conductivity is inversely to resistance. What are insulators? Non-conductors. ELECTRICITY. 29 What is the law of electric attraction and repulsion ? Bodies charged with the same electricity repel each other; bodies charged with opposite electricity attract each other; or like electricities repel, unlike attract. How is electricity distributed in bodies ? On the surface, with increased polarity at projections, from which, if sufficiently attenuated, it may even discharge itself into the surrounding air. How may electricity be produced besides by friction ? By induction; electrified bodies attracting in neighboring bodies, not in contact with them, electricity of a different de- nomination towards them. What is the arrangement of simple cylinder electric machines? They consist of a glass cylinder, which, by a crank, may be rotated against a silk cloth or cushion containing amalgam. Close to this cylinder is an insulated metal globe which presents a number of points towards it. As fast as the positive electricity is exerted in the glass, the negative induced in the globe escapes to it from the points, and leaves the residuary positive electricity in the metallic insulated globe to increase with each rotation. What is an electrophorus ? An apparatus by which, through difference of potential and induction, considerable electricity may be stored up and dis- charged. It consists of a metal cover with an insulated handle placed on an electrified layer of shellac or resin ; in this way its lower surface becomes positive and the upper negative. If the negative is discharged the more positive accumulates, and if lifted oft'will give a positive spark. What is a Toepler-Holtz machine, and upon what principle is it based ? An electrical machine consisting of two upright glass plates, one stationary, and of uneven potential, which by rotation is multiplied, and by induction stores up electricity in the armature of the fixed plate. The principle is similar to that of the elec- trophorus. 30 ESSENTIALS OF MEDICAL CHEMISTRY. What is an electrometer ? A pith ball attached to a movable lever repelled from a knob electrified with the same denomination, thus indicating the electric tension. What are Leyden jars, and what batteries? Instruments for the accumulation of electricity ; they consist of glass jars coated inside and outside with tinfoil, the inner being connected with a wire and knob. When the outer con- nects with the earth and the inner with an electrical apparatus, they become charged respectively with negative and positive electricity, and when so charged may be discharged and give rise to a spark. If several such jars are connected together to in- crease their effect, they are termed an electric or Leyden battery. What is the character of electric sparks ? They move in the air in broken lines, as the air offers resist- ance to their passage by becoming condensed ; thus the zigzag course of lightning. What are the phenomena displayed by insulated electrified persons ? Their hair, when dry, stands on end, and sparks may be drawn from their bodies. State the medical use of static electricity. In nervous affections, hysteria, and palsy, the patient being insulated, and sparks drawn from him, then muscular contrac- tions will ensue. What is thermoelectricity ? The electricity produced when two different metals joined to- gether at each end have their joints unevenly heated; the strength of this depends on the difference of temperature be- tween the two joints. What are the thermoelectric batteries or piles ? A combination of thermoelectric pairs, principally of bismuth and antimony, or platinum and iron, so that heat may be ap- plied to, respectively, the first, third, fifth, etc., joints, while the others are kept cool. ELECTRICITY. 31 What is the principal use of thermoelectric piles or batteries ? To indicate slight changes of temperature by its effect upon the needle of the galvanometer. What is galvanism ? Chemical electricity, also termed voltaism, also dynamic elec- tricity ; the electricity produced when two bodies are immersed in a liquid, acting on them with unequal chemical energy. What are the bodies generally employed for this purpose, and which are the principal ones? The metals more generally, and zinc always one of them. Thus, zinc and copper, zinc and carbon, zinc and platinum, zinc and silver, etc. What are such two plates termed, and what a series of them ? A voltaic couple or element; a series of them a voltaic column or pile. Which is the positive and which is the negative plate ? The one being acted upon more energetically is termed the generating plate and has a higher potential; the current flows from it to the lower potential; the plate from which the current flows in the liquid being termed the positive, while the one to which it flows through the liquid is the negative. When the two plates are joined outside of the liquid by the polar wire, in which direction does the current flow therein ? The outside current flows from the negative plate to the posi- tive. The ends of the wires are termed poles or electrodes, and their denomination is the opposite from that of the plates they are attached to. Thus the one attached to the negative plate is at its termination called the positive pole or electrode, while the other attached to the positive plate forms the negative pole. What are the positive and negative poles also called ? The positive pole is called anode, and the negative pole ka- thode. 32 ESSENTIALS OF MEDICAL CHEMISTRY. If plates of zinc and copper are immersed in dilute sulphuric acid, and connected outside of the fluid by a wire, what results ? There will be an energetic chemical action at the zinc plate, hut the disengaged hydrogen will accumulate at the copper plate in such a measure as soon to stop the galvanic current passing through the wire ; the copper plate is then said to be polarized. What is then polarization of the plates, and how avoided ? Polarization of the plates means the accumulation of disen- gaged gas thereon, and the consequent interruption of the cur- rent. The polarization may be corrected by mechanical means, such as shaking, etc., or, as shown subsequently, by special arrangement of the fluid or fluids, so that the disengaged hydro- gen will be chemically bound in the fluid. Why should the zinc plates be amalgamated ? lo overcome local action or currents caused by the impurities of the zinc and other metals present therein. What are galvanic elements, and what batteries ? A single cell, containing two plates of different potential, im- mersed in suitable battery fluid in a stone, glass, or rubber vessel, constitutes an element;and a number of them, properly arranged or coupled, are termed a galvanic battery. What is a Daniell’s element? what its advantage? about what is it equal to in electromotive force ? and what is the ob- ject of its arrangement? A glass vessel containing a saturated solution of copper sul- phate, and in this a copper cylinder. Immersed in the copper solution, and inside the copper cylinder, is a porous cup filled with dilute sulphuric acid and containing a zinc cylinder. Its constancy of action makes it of special advantage, and it is for this reason that its electromotive force is accepted as a unit or nearly so. The principle of its action is chemically to overcome polarization ; for as the hydrogen from the zinc passes to the copper it decomposes the copper sulphate solution, substituting the atom of copper of the CuSO., forming thus 11,80*; the lib- ELECTRICITY. 33 erated copper is deposited on the outside copper cylinder, while the newly-formed II2S04 passes into the porous vessel to act on the zinc. Describe the arrangement of a Grove’s element. A two-fluid cell, containing, outside, zinc, immersed in dilute sulphuric acid; inside the porous cup is a platinum slip in nitric acid. The hydrogen evolved at the zinc, and passing to the plati- num, decomposes the nitric acid, thus also chemically preventing polarization. What is a Bunsen’s element ? A two-fluid cell, arranged similar to Grove’s, with a com- pressed gas retort carbon being substituted for the platinum. The object and principle are the same as in the former. What is a Smee’s element, and how is polarization prevented by it? A single fluid cell, in which a platinum sheet is immersed in dilute sulphuric acid between two zinc plates. The platinum sheet is covered with small fragments of platinum, or a silver plate covered with finely divided platinum may be substituted for it; the platinum particles mechanically aiding the disengage- ment of the hydrogen from the platinum. Describe the arrangement of a Grenet cell. A one-fluid cell, containing two fixed carbon plates, immersed in a battery fluid of sulphuric acid and potassium bichromate. Between the carbons is a zinc plate which can be lowered into the fluid to set it in action. The object of the potassium bichro- mate is to form chromic acid, which oxidizes the hydrogen into water. Give the arrangement of a Leclanche element. A porous cup containing a carbon rod, surrounded by pieces of peroxide of manganese and gas carbon. Outside the porous cup is a saturated solution of ammonium chloride, and immersed in it a rod of zinc. What is a Calland’s or gravity element? A modification of Daniell’s element, doing away with the 34 ESSENTIALS OF MEDICAL CHEMISTRY. porous cup. It consists of a star-shaped copper plate at the bottom of the vessel, which is surrounded by pieces of copper sulphate ; it is immersed in a saturated solution of the same sub- stance. The upper half of the vessel is occupied by dilute sul- phuric acid, which, by the difference of density, floats on the cop- per solution, and contains suspended in it a star-shaped arrange- ment of zinc. Its action is the same as in the Daniell, and is very constant; it is principally used in telegraphy. What is the electrical tension or potential ? The electricity accumulated at certain points. What is electromotive force ? The amount of electricity generated by an electrical battery. It is generally accepted as the difference of potential of the two plates. What is the electromotive series of metals ? The arrangement of metals according to their electrical de- portment ; the most electropositive being at one end and the most electronegative at the other, as follows : 1. Zinc. 2. Cadmium. 3. Tin. 4. Lead. 5. Iron. 6. Nickel. 7. Bismuth. 8. An- timony. 9. Copper. 10. Silver. 11. Gold. 12. Platinum. 13. Graphite. Thus iron in dilute sulphuric acid is electronega- tive to zinc but electropositive to copper. What is the law for the electromotive force between two metals ? That the electromotive force between two metals is equal to the sum of the electromotive forces between all the intervening metals. What is a volt ? The unit of electric pressure or electromotive force. It is about the electromotive force of one Daniell’s element. What is generally understood by the electric current ? The current of electricity passing through the wire. What is the direction of the outside current ? From the electronegative plate (carbon or copper), to the electropositive (zinc). ELECTRICITY. 35 On what does the current strength depend, and by what is it diminished ? The current strength depends on the amount of electromotive force, and is diminished by the resistance which it encounters. How may the relations then be stated? The current strength is directly proportional with the electro- motive force and inversely with the resistance. What is the resistance, and what two resistances do we en- counter in a galvanic cell ? The force opposing the flow of the current is the resistance ; that existing in the liquid between the plates is termed internal resistance ; that diminishing the conductivity of the wire is called external resistance. What is the law governing the resistance of a conducting wire ? The resistance is inversely as the cross section, and directly as the length of a conductor. What is the unit of resistance ? The “Ohm;” the resistance offered by a column of mercury, 104.81 centimetres long, one square millimetre in section at CPC. What is the unit by which current strength is computed ? The ampfere ; the current strength of one volt of electromotive force passing through a circuit having one Ohm resistance. How may the current strength be computed ? By the Ohm’s law ; the current strength is equal to the elec- tromotive force divided by the resistance, as per following formula: C = Of what advantage is the application of the Ohm’s law in galvanism ? The advantageous coupling of the elements with a view to greater intensity or quantity. When is the combination best for producing intensity ? By increasing the internal resistance; i. e., coupling the dif- ferent elements separately as such, as needed in galvanization of muscles and nerves, and also in electrolysis. 36 ESSENTIALS OF MEDICAL CHEMIST KY. How are the elements to be coupled for quantity ? By combining all the zincs together and also the carbons, thus diminishing internal resistance; this is the combination em- ployed for galvano-eautery and lighting purposes. How is electric light produced for medical purposes? By passing a galvanic current of quantity through a carbon filament or platinum wire contained in an airless glass globe, when the resistance to the current will produce the luminous effect. What is the principle of the galvano-eautery ? A thin platinum wire by the passage of a quantity of electricity will be intensely heated, and can then be applied for cautery purposes. What is the effect of an electric current passing around a mag- netic needle ? It will deflect the needle from its position. In which direction is the needle deflected by the galvanic current ? This depends upon the direction the current passes, and if above or below the needle. Bor ready comprehension a person may imagine himself floating in the current with the head in direction of the current and facing the needle, when the north end of the needle will be deflected to the left. What is a galvanometer ? An instrument so arranged as to indicate by the deflection of the needle the existence, direction, and intensity of currents. It is generally composed of astatic needles and multipliers. What instruments are employed to indicate the current strength for medical purposes ? Those indicating the amount of amperes, or rather milli-am- peres, passing through the circuit. They are termed ampere or milli-ampere-meters. What is the effect of an electric current passing around soft iron ? It makes a very powerful temporary magnet. ELECTRICITY. 37 When the current is broken or opened, and when made or closed, what takes place, and to what purpose is it ap- plied ? The iron is magnetized when the circuit is closed, and becomes demagnetized when opened. On these phenomena the electric telegraph is based. What is Faradism ? The electricity developed by induction from the galvanic current. How can this be illustrated ? By placing a wire, not connected with any battery, close and parallel with a wire connected with a galvanic battery; there will be an electrical manifestation in the former every time the galvanic current is made or broken. How does the induced current make itself manifest, and in what direction does it flow ? • It is not a steady current, deflecting the galvanometer needle only at the time the primary current is closed or open. When the current is closed, it flows in an opposite direction to the primary current, but on breaking it is reversed. Has the faradic current chemical properties, and if not, why not? It has no chemical powers, because it is a to and fro current, and its action in one direction is neutralized by the return flow. How may very powerful electric manifestations of the induced current be developed ? By multiplying the secondary wire. What are the instruments for this purpose, and component parts? RuhmkorfF coils; consisting of a primary coil, an iron core therein, an automatic breakpiece or interrupter, a secondary coil, and an accumulator or condenser for the extra current. Which is the longer, the primary or secondary coil ? The secondary, which is on the outside, and often contains many miles of wire. 38 ESSENTIALS ' OF MEDICAL CHEMISTRY. What is the object of the iron core? To attract the breakpiece when it becomes magnetized. What is the breakpiece ? A spring connecting with the primary wire by a small plate of platinum, and having a small hammer end, which is attracted when the core is magnetized ; it thus breaks the current, and springs back when the core is demagnetized, when the current is again made. What does the condenser consist of, and what is its object? It consists of layers of glass covered with tinfoil, acting on the principle of a Leyden jar. It accumulates and condenses the extra current. On what principle are medical faradic batteries constructed ? Similar to that of the Ruhmkorff coil with a Grenet cell to fur- nish the primary current. What measures should be adopted to insure the good working* of a faradic battery ? The interrupter should be kept free from rust and corrosive material; all connections should be tight, insulations should be complete, and the battery fluid should not be allowed to dry out, or become decomposed. When the purely faradic current is employed, does it matter how the poles are disposed of? No ; as the current goes both ways. What is the principal use of the faradic current in medicine? To excite nerves or bring about muscular contractions, both for diagnostic and therapeutic purposes. What is the use of the constant galvanic current in medicine ? For nerve stimulation, for cautery, and for its chemical effect. What is the chemical effect of the galvanic current, and what is it termed ? The chemical decomposition of compounds in a fluid state ; it is termed electrolysis. ELECTRICITY. 89 What takes place when water is subjected to electrolysis, and how does it take place ? It is decomposed into its constituent elements, hydrogen and oxygen. The hydrogen accumulating at the negative (—), the oxygen at the positive (-(-) pole or electrode. What are substances called subjected to electrolysis? what the results? what are these which go to the positive and those that go to the negative pole ? The products of decomposition are termed IONS ; the subjects for electrolysis are electrolytes ; those which go to the negative pole, the kathode, kathions ; those which go to the positive pole, the anode, anions. What takes place if a galvanic needle is inserted in the human body? The salts and fluids are decomposed ; alkalies and hydrogen go to the negative ; oxygen and acids go to the positive pole. What is electrolysis used for in medicine ? For removing tumors, hairs, neevi, warts, etc. In the electrolysis of tumors, what needle should be inseited into them, which in aneurisms, and why ? The electronegative in tumors, the electropositive in aneu- risms ; because the alkalies at the negative pole liquefy the tissues, while the acids at the positive pole condense them, and coagu- late the blood. 40 ESSENTIALS OF MEDICAL CHEMISTRY. CHEMISTRY. What is chemistry ? That branch of physical science which treats of the composi- tion of matter. What are physical, what chemical changes? Physical changes are those which do not affect the composition or construction of the molecule ; chemical changes, those altering its character, and thus changing matter itself. What is chemism ? That form of attraction which takes place between atoms. What is a molecule ? The smallest particle of matter that can exist in a free state, and cannot be divided without losing its character. What is an atom? The chemical unit of matter produced by the breaking up of the molecule. How may matter be subdivided ? Into simple or elementary and compound matter ; termed rela- tively elements and compounds. Define simple or elementary and compound matter. Matter made up of molecules, containing like atoms, is ele- mentary ; that whose molecules are made up of dissimilar atoms is termed compound. How many elements and therefore different kinds of atoms are known ? At the present time about sixty-six are definitely known as such. How are atoms designated in chemical notation ? example. By symbols, consisting of the first, or the first and some other letter of their Latin name. H for hydrogen, B for bismuth, Pb for lead (Plumbum), Ilg for mercury (hydrargyrum), etc. CHEMISTRY. 41 What do symbols express besides the atomic character ? The atomic weight. What is atomic weight ? The relative weight of an atom in comparison with the hy- drogen atom as a unit. It also expresses the smallest quantity of an elementary substance capable of entering into the formation of a chemical compound. In which way is the quality of the combining power of an atom expressed ? By its electrical polarity in relation to another atom. Thus, atoms are either electropositive, i. e., accumulating at the electro- negative pole, or electronegative, i. e., accumulating at the electro- positive pole during the electrolysis of a compound. Is the electro-chemical character of atoms definite or relative ? It is relative in so far that an atom is electropositive towards some, electronegative towards others, but it is definite in these relations ; thus, the metals are electropositive to the metalloids, and these are electronegative to the former. What is the quantity of atomic combining power ? The fact that some atoms can combine with one atom of hy- drogen, and others with two, three, and more of it, demonstrates the quantitative combining power of atoms. What is then the equivalence of an atom ? The quantity of its combining power expressed in hydrogen units, or the number of hydrogen atoms it can combine with, or be exchanged for. How is the equivalence of atoms expressed, and how is it writ- ten in notation ? Either by the use of Greek numerals, as monads, dyads, triads, tetrads, pentads, hexads, and heptads, or by Latin numerals, as univalents, bivalents, trivalents, quadrivalents, quinquiva- lents, sexivalents, and septivalents. In chemical notation this is expressed by placing Roman numerals above, and to the right of the symbol: H1. O11. 1ST11. CIV. AsL Syi. Clvn. 42 ESSENTIALS OP MEDICAL CHEMISTRY How may the equivalence of the atom be graphically repre- sented ? By illustrating the atom as a small ring or dot or symbol, and the equivalence by lines radiating from it; these lines are termed bonds, as follows :— Monad. Diad. Triad. Tetrad. Pentad. Ilexad. Heptad When an atom combines with another in several proportions, what characteristic series appear, and into what two groups are they accordingly classed ? Its higher compound always increases by two, as for in- stance, 1, 3, 5, and 7, or 2, 4, and 6. These two can never inter- change, and the series whose equivalents are in even numbers are termed artiads, while the odd are called perissads. In which way are multiples of atoms expressed in chemical notation ? By placing small Arabic numerals to the right and below the symbol, for instance, Cl2, 03, As4. What do groups of atoms represent, and what is their chemical notation termed ? They represent a molecule, and their designation in chemical notation is termed a formula; for example, NaCl, II2So4, etc. How are multiples of molecules expressed ? By inclosing their component symbols in parentheses and placing a small Arabic numeral outside to the right and below, or by placing a larger numeral before the molecule without parentheses ; thus, (NaCl)2 = 2 J7aCl. In which way is a reaction to take place between two chemical bodies designated, how its completion, and how the pro- duct or products ? Before the reaction takes place they are separated by a plus sign (-}-), the union complete by an equation sign (=), and the product by its formula, or, if more than one, they are separated by plus signs ; example, NaOII -1- IIC1 = NaCl + HaO. CHEMISTRY. 43 What are empyrial, what rational, and what graphical formulse ? An empyrial formula is one expressing the kind and number of atoms in the molecule. A rational formula indicates, besides this, the arrangement of the atoms in the molecule. The graphical are simply illustrations of rational formulte. H I C II—cf \c—0—H II—yC—ll %/ c I H Graphical formula. C6II60 Empyrial formula. C6H5.OH Rational formula. What two kinds of molecules can be chemically distinguished ? The elementary molecules composed of atoms of the same kind, and the compound, composed of atoms of dissimilar elements. Give the definition of molecular weight. The sum of the atomic weights of a molecule. How may compound molecules be classified? Binary molecules in which the atoms unite directly, and ternary molecules in which the atoms are indirectly united. Of how many kinds of atoms are binary molecules always com- posed ? Of only two different kinds of atoms. What is the rule for naming binary molecules ? As they must be composed of electropositive and electro- negative elements, the electropositive is always placed with its full termination first, while the electronegative has its terminal syllable changed to “ide”; thus, potassium chloride, hydrogen sulphide, calcium fluoride, etc. 44 ESSENTIALS OF MEDICAL CHEMISTRY. When an electropositive element unites with the electronegative in more than one proportion how are the two compounds distinguished by name ? By the affix of “ ic” to the one and “ ous” to the other; exam- ples : mercuric oxide, mercurous oxide ; ferric chloride, ferrous chloride. When there are other compounds by change of valence how are they expressed by name ? The electropositive of the lower receives before its name the affix of “ hypo” and the highest that of “ per”; thus, hypo- chlorous oxide and per-chloric oxide. How are multiples of the same kind of atoms in the name of the compound molecule expressed ? By the prefix of Greek numerals, such as carbon dioxide, sul- phur trioxide, nitrogen tetroxide, arsenic pentoxide. Some- times the multiple of the electropositive is similarly expressed, as in di-nitrogen tetroxide, di-arsenic pentoxide. What are compound radicals ? Unsaturated molecules, not existing in a free state, but cap- able of uniting directly with an atom or a similar compound to form saturated molecules. What is the rule for naming them and their compounds with atoms? That they end in yl; example : IIO—Hydroxyl; but some, as amidogen Nll2—Cyanogen ON—differ in this. Their compounds with atoms are subject to the same terminology as binary molecules. What is a ternary molecule? One in which two dissimilar atoms are united by means of a third having linking functions. Which are the atoms having linking functions? The principal one is oxygen, but sulphur, selenium, and tellurium also possess this function. What three classes of ternary molecules are distinguished? Acids, bases, and salts. CHEMISTRY. 45 What two kinds of acids do we distinguish ? Binary or hydracids, and ternary or oxyacids. Give the definition of an acid. A compound of hydrogen with an electronegative which can give up its hydrogen for the metal of a base to form a salt. How is an oxyacid constituted? It is a compound in which hydrogen is united by oxygen to an electronegative. H—O—R. What is a base ? A compound containing hydrogen united by oxygen to an electropositive. II—O—It. What is a salt ? A compound in which one or more electropositive atoms are united by oxygen to one or more electronegative atoms. R—O—R. What are the characteristic properties of bases, and what of acids ? Bases turn turmeric paper brown, and reddened litmus paper blue ; acids turn blue litmus paper red. Upon what type may the above be said to be formed ? The water type, because by replacing one H of H-O-H with — + R an acid is formed, by Ra base ; by replacing both II, one with R the other with R, a salt results. What names are applied to the bases ? Considered as compounds of the radical hydroxyl, they are named hydroxides or hydrates; thus, KOH potassium hydrate, UaOH sodium hydrate. What terminal endings are affixed to the acids ? Acids are expressed by the affix of “ic” to the abbreviated electronegative. The hydracids besides receiving the prefix “ hydro, ” the higher acids of an acid, terminate in “ic,” the lower in “ous.” Thus, IIC1 hydrochloric acid, II2S04 sulphuric acid, II2S03 sulphurous acid. 46 ESSENTIALS OF MEDICAL CHEMISTRY. What are the names of salts according to the acids used in their formation ? Hydracids form binary compounds, ending in “ ide “ ic” acids form “ate” salts; “ ous” acids form “ ite” salts; “hypo” acids form liypo-ites ; “per” acids form “ per-ates ;” thus, hydrochloric acid forms chlorides; sulphuric acid forms sulphates ; sulphurous acid forms sulphites ; hypochlorous acid forms hypochlorites ; perchloric acid forms perchlorates. What expresses the basicity of acids and the acidity of bases ? The basicity of acids depends on their amount of replaceable hydrogen, and the acidity of bases on their number of hydroxyl groups; example, HN03 monobasic acid, II2S04 dibasic acid, etc. KOH. monoacid base, Ca (OII)2 diacid base. What are normal, acid, basic, and double salts ? Normal salts, those having neither acid nor basic hydrogen in excess ;acid salts, those containing basic hydrogen in excess; basic salts, those having acid hydrogen in excess ; double salts, those containing two or more different positive atoms. Thus, normal salt, Ca8(P04),; acid salt, NaH2P04; basic salt, PbOH (C2H302); double salt, NH4Mg P04. What is the ammonia type, and the terms of its compounds ? The type of compounds formed by substituting the hydrogens of ammonia Nil,; the substitution of II by an electropositive atom or radical forming an “ amine ;” the substitution of H by an electronegative atom or radical forming an “ amide ;” while the substitution of an II by an electronegative and another by an electropositive, yields an alkalamide. What are the further denominations of amines and amides? According to the number of II substituted they may be mon- animes, di-amines, and tri-amines, or mon-amides, di-amides and tri-amides ; the names of the electronegative or electropositive atoms or radicals displacing the H, being placed between the Greek numeral and the words amine or amide. If more than one of the Nil, group enter into the compound, the substituting radicals are placed before the Greek numeral which are used CHEMISTRY. 47 according to the number of H left. Thus, ethylamine, di- or tri-ethylamine, mono-di- or tri-acetamide ; in the last case, how- ever, carbonyl-di-amide, etc. What are the relative volumes of the molecules of all bodies in a gaseous state ? The volumes of molecules of gases are alike ; or equal volumes of gases contain equal numbers of molecules. How do gases combine? Volume for volume when both are monads, two and one when monad and dyad, three and one when monad and triad, etc. How many volumes result in all these cases ? Two volumes or two molecules, if each combining volume is one molecule. When one molecule of hydrogen and one molecule of chlorine unite, what is formed ? Two molecules of IIC1. What does this prove ? That, as two molecules of IIC1 were formed, each contains one atom of II and one of Cl, the molecule of hydrogen and of chlorine contain each two atoms. What is stoichiometry ? The computation of the weights of bodies entering into chemi- cal combinations and their results. How are the molecular weights of chemical bodies determined ? By adding together the atomic weights of the component atoms. Thus II.,S04— ’211= 2 S = 32 40 = 64 Total = 98 = molecular weight of II2S04. When HNOj unites with KOH, what results? formula ? HNO3+KOH = + II.p. 48 ESSENTIALS OF MEDICAL CHEMISTRY. What does this equation also stand for in weight units ? 1 + 14 + 48 39 + 16 + 1 39 + 14 + 48 2 + 16 63 + 56 101 + 18 How may the elements be classified for convenience of study ? Into metals and non-metals, which are again grouped accord- ing to their valences, electro-chemical relations, as well as physical and chemical characters; hydrogen and oxygen are grouped by themselves as typical elements. Thus— Non-Metals. Group I. Hydrogen and oxygen. Group II. Electronegative monads, or Chlorine group. Fluorine, chlorine, bromine, iodine. Group III. Electronegative clyads, or Sulphur group. Sulphur, selenium, tellurium. Group iy. Electronegative triads, or Nitrogen group. Nitrogen, phosphorus, arsenic, antimony (bismuth, see metals). Group y. Boron. Group yi. Electronegative tetrads or Carbon group. Carbon, silicon. Metals. Group I. Alkali metals. Lithium, sodium, potassium, rubidium, caesium (ammonium). Group II. Metals of the alkaline earths. Calcium, strontium, barium. Group III. Magnesium group. Magnesium, beryllium, zinc, cadmium. Group IV. Lead group. Lead, thallium. Group Y. Copper group. Copper, silver, mercury. Group yi. Yttrium group. Yttrium, erbium, terbium, yterbium, scandium, deeipium, lanthanum, cerium, didymium. CHEMISTRY. 49 Group VII. Aluminium group. Aluminium, indium, gallium. Group VIII. Iron group. Manganese, iron, cobalt, nickel. Group IX. Chromium group. Chromium, molybdenum, tungsten, uranium. Group X. Tin groupj. Tin, titanium, zirconium, thorium. Group XI. Bismuth group. Vanadium, bismuth, tantalum, niobium. Group XII. Platinum group. Gold, platinum, palladium, rhodium, iridium, ruthenium, osmium. 50 ESSENTIALS OF MEDICAL CHEMISTRY. Hydrogen. What is hydrogen, and what its properties ? A colorless, odorless, tasteless elementary gas, rarely found free in nature. Symbol H, atomic weight 1, valence1, molecu- lar weight 2 ; one liter at 760 mm. pressure and 0° C. weighs 0.08958 grains = 1 erith. It is combustible, but not a supporter of combustion. A mixture of II and O will explode violently when lighted, forming water. How can it be demonstrated that it is lighter than air? A balloon or soap-bubble tilled with it will rapidly ascend. It can be readily transferred by pouring it from one inverted vessel into another from below upwards, displacing the air in doing so. What is its diffusibility ? It is highly diffusible, penetrating through porous bodies with ease, and diffusing through membranes. Is hydrogen under all circumstances and conditions a gaseous body? It can be reduced to the liquid state by cooling to —140° C., and under a pressure of 600 atmospheres. It then resembles a steel-blue, non-transparent fluid, somewhat like mercury, and upon evaporation even solidifies. How can the formation of water by the union of H and 0 be proven ? If a flame of hydrogen is allowed to burn in a cool glass cyl- inder, this will soon be found covered with dew. How can hydrogen be prepared ? By electrolysis of water, by the action of some metals on water, and by the action of zinc or iron on sulphuric or hydro- chloric acid. What is the result of the electrolysis of water in the Hoff- mann’s tubes, and how is the presence of H proven? When acidulated water is subjected to electrolysis, the II will accumulate in the tube containing the negative electrode, the O CHE MISTKY. 51 in that containing the positive electrode. There will be besides a definite relation between the volumes of the two gases so liber- ated, that of H being twice that of O, showing the composition of water as II20. The presence of H can be proven by collect- ing the gas in a test tube, and burning it, water resulting. How can hydrogen be prepared from water by the action of metallic potassium or sodium ? Sodium or potassium, by superior chemical attraction for oxygen, displaces at ordinary temperature one II, and unites with the residuary HO, as per following formula :— H,0 + Ha = NaOH + H. Can other metals produce the same resuit? Iron at red heat will do the same, uniting with O and liber- ating II. What is the most common process for obtaining hydrogen for experimental purposes ? The action of zinc or iron on sulphuric or hydrochloric acid, the metal replacing the II of the acid and setting this free to be collected, as per following formula :— Zn+H2S04=Zn S04+2H. What other process is employed for obtaining H in Fleitmann’s test ? The action of aluminium metal on sodium- or potassium- hydrate at ordinary temperature, or that of zinc at the boiling point, as follows : A1-J-3K0H=K3A103-J-3H. For what purposes is hydrogen in its nsscent state used in chemistry ? As a reducing agent, i. e., to take away from and unite with the oxygen of other bodies. What is the physiological effect of inhaling hydrogen, and why? It produces a higher pitch of the voice on account of the more rapid vibrations of the vocal cords in a less dense atmosphere. 52 ESSENTIALS OF MEDICAL CHEMISTKY. Oxygen. What is oxygen ? Its properties ? A colorless, odorless, tasteless, elementary gas. Symbol, O, a. w. 1G, valence11, m. w. 32; one litre weighing at 0° C. and 700 mm. 143 grams. It is liquefied at —130° C. and 470 atmospheres pressure; it is slightly soluble in water (about 3 per cent, at 15° C.). It is a supporter of combustion, but not combustible. It unites with all the elements excepting fluorine, forming with them compounds termed “oxides.” What is the process termed when oxygen unites with another element, and amidst what phenomena does it usually take place ? Oxidation, which, if it takes place rapidly, is generally accom- panied by development of heat and light, and is then termed combustion. Where is oxygen found, and in about what proportions ? It is the most abundant element in nature, existing free in the atmosphere, and in combination with other elements; it composes about two-tliirds of the entire globe. How may oxygen be prepared ? By heating mercuric oxide to a high temperature it is decom- posed into mercury and oxygen. IIgO=Hg-f-0. How is it prepared from potassium chlorate ? By heating the coarsely powdered KCIO, and collecting the escaping gas; as this gives rise to irregular and violent evolu- tion of the gas, about one-fourtli of its weight of powdered manganese dioxide is mixed with it, which causes the more even liberation of the gas and at a lower temperature ; the manga- nese dioxide, however, takes no chemical part in the process. 2KC10.(=2KCl-f 30,. In what other processes is oxygen liberated? In the electrolysis of water, also by the action of sunlight upon the leaves of plants. CHEM 1ST H Y. 53 What takes place if a piece of magnesium wire is ignited, and what is the product ? It deflagrates, emitting a very bright light, leaving as a white ash the magnesium oxide. If a glowing charcoal ember, ignited sulphur, phosphorus, cr a heated steel wire, is immersed in a jar containing oxygen what takes place, and what are the results ? They deflagrate rapidly, giving rise to heat and light, leaving as results the oxides of the different substances used. The car- bon produces C02, the sulphur S02, the phosphorus P205, the iron Fe203. What is the oxy-hydrogen flame, and how applied to the lime light? A flame produced from burning oxygen and hydrogen from a special burner. It is not luminous but very hot, melting even platinum, etc. I3y exposing to it a piece of lime, this becomes incandescent, and emits a bright white light. Is slow oxidaticn, such as the rusting of iron in the air, different in its result from rapid oxidation or combustion ? They are identical processes and yield the same results ; the heat given off' in rapid combustion is also given off, hut appa- rently insensibly, in the slow oxidation. What chemical process is going on in the burning of coal oil, candles, etc. ? An oxidation of their component parts ; their carbon forming carbon dioxide C02, and their hydrogen water II20. What is the part oxygen takes in the physiological process ? It is carried by the haemoglobin of the red blood corpuscles to the tissues, where it unites with their carbon and hydrogen, forming carbon dioxide and water •, the former of these as a waste product is given off by the lungs ; the heat liberated by this oxidation produces either animal heat or is converted into the other physiological forces. 54 ESSENTIALS OF MEDICAL CHEMISTRY. Why are inhalations of oxygen of no benefit in the treatment of disease ? Because the corpuscles cannot take up more or in a different dilution than formed in the atmospheric air. It is proven that animals when kept in an atmosphere of oxygen, do not exhale more C02 than when kept in air. Ozone. What is ozone ? Its properties ? Condensed oxygen ; triatomic molecules of oxygen, Os, of a density of 24 (III), m. w. 48. It possesses a penetrating chlorine odor and a bluish color; it is coercible at high pressure and low temperature yielding drops of indigo blue color. At 300° C. it becomes diatomic oxygen. It is chemically very active, oxidizing other bodies readily and bleaching organic coloring matter; it is absorbed without change by oil of turpentine and other essential oils. What may ozone also be said to be ? An allotropic form of oxygen, i. e., a substance which, though qualitatively of the same elementary composition, has different physical and chemical properties, owing to the difference of its molecular structure. How is ozone prepared ? 1. It forms when phosphorus is exposed to moist air or oxy- gen. 2. By the addition of small quantities of potassium per- manganate or barium peroxide to cold sulphuric acid. 3. By an electric discharge through the air or oxygen. How is it best prepared ? By the silent discharge of a powerful current from a Ruhm- korff coil through a Siemen’s induction tube, through which freshly prepared oxygen is allowed to flow. How is ozone recognized ? By its action on potassium iodide starch paper ; as it decom- poses the KI into K and I, the I turns the starch blue. Tincture of guaiacum is turned blue and lead acetate brown by 03. 55 CHEMISTRY. Hydrogen peroxide answers the same test, but 03 in addition blackens bright strips of silver. What influence has ozone on epidemic diseases ? It is said to arrest them by oxidizing the organic material giving rise to them. When and where is ozone found ? It is found in the air, especially after thunder storms, and abounds in high latitudes, the seashore, etc. What is the effect of inhaling air rich with ozone on the res- piratory organs ? It irritates them, causing coryza and even heemoptysis. Compounds of Hydrogen and Oxygen. Water. How can the composition of water be proven? By analysis and synthesis. What is analysis and what synthesis ? how can they he applied to water ? Analysis means the decomposition of a molecule into its com- ponent atoms, and synthesis the recomposition of the constituent atoms to form the molecule. Electrolysis effects the analysis of II20 into 2H and 10 ; and if two volumes of II and one of O are mixed, and united by an electric spark passing through them, water is formed. What is water ? Its properties ? A compound of H and O; formula H.,0, m. w. 18, density 9, sp. gr. 1; solidifies at 0° C. ; boils at 100° C. It is a limpid, color- less, odorless, and tasteless liquid. Its maximum density is at 4° C =39, 2° F., at which point its liter weighs 1000 grams. It is a poor conductor of heat and electricity. At 0° C. it solidifies, and is then known as ice ; at 100° C. it boils and assumes a gas- eous form, known as steam. Its solvent powers are very great. What are the chemical properties of Ha0 ? It is chemically very active, uniting with the oxides of the 56 ESSENTIALS OF MEDICAL CHEMISTRY. electropositives to form bases (CaO + H./) = Ca(OII)2), and with the oxides of electronegatives to form acids (C02 + II20 = H.2C03). How may water influence the molecular structure of crystal- line bodies? It enters into the molecular structure of many crystalline bodies without forming a chemical part thereof; when this is given up by them spontaneously they are termed efflorescent, and when they attract more from the atmosphere and liquefy, they are called deliquescent. When containing no IIX) molecule, a body is called anhydrous. What is distillation, what sublimation, and what distilled water ? Distillation means the volatilization of liquids, condensing and recovering their vapors in special apparatus. Sublimation is the same process applied to volatile solid bodies. Distilled water is the water purified by the former method for chemical and other purposes ; it is however not absolutely pure. Define the term potable, hard, temporary-hard, permanently- hard, and soft water. Potable is water when suitable for drinking purposes; hard is water when it contains calcium or magnesium salts, and does not lather with soap ; when it contains the carbonates of calcium or magnesium in solution and removable by boiling, it is tem- porarily hard ; when the hardness is due to other soluble salts of Ca or Mg not removable by boiling, it is permanently hard. Soft water contains little or no mineral salts in solution. What is the purest natural water, and what does it usually contain ? Rain- or snow-water, if not contaminated in collecting; it con- tains little solid matter, except traces of ammonium nitrite and nitrate, but some oxygen, nitrogen, and carbon dioxide in solution. What is the principal contamination to guard against in rain- water for potable purposes ? Lead from roofs or pipes, as the nitric and nitrous acids, as well as nitrates, render soluble compounds with lead. CHEMISTRY. 57 Which waters contain, besides solid ingredients, notable quan- tities of organic material ? River waters, especially those draining marshes or running sluggishly through marshy bottoms. Is organic material admixed to water always deleterious, and when is it? In itself organic material is not injurious, but as it is a soil for disease germs it is objectionable; when it arises from draining off animal excreta it may contain disease germs which render it dangerous to health. rlhus sewage contamination of water is apt to contain germs which can proliferate in organic material, and breed disease. What other admixture is found in river water, and of what im- portance is it ? Rivers running through alluvial soil may through freshets also contain in their waters suspended matter, which, when of min- eral origin, is of no especial significance, but if it arises from organic source may become dangerous to health. How may river water be purified ? By storage and sedimentation, allowing undissolved mineral and organic matter to be deposited ; by aeration, so that oxygen of the atmosphere oxidizes the organic matter; by filtration, restraining undissolved particles by interposed gravel beds; finally, by dilution from additional pure sources into its course. What precaution should be observed in selecting a water supply from rivers ? To select the source of supply sufficiently far away from large cities, and as far as possible below any places of habitation ol- factories emptying their refuse into it. What objection is there to well-water? That it contains surface water drained from cesspools, and that it is impregnated with both organic and inorganic material. The deeper the wells are, the danger from this source diminishes. 58 ESSENTIALS OF MEDICAL CHEMISTRY. What are deep and artesian wells, and the character of their water ? Wells sunk through impermeable strata, receiving their water from large distances, or from the underground flow of rivers. Their water is usually free from organic material, but abundant with mineral ingredients. What are the source and character of spi ing-water ? Springs generally receive their supply from rain-water which has filtered into deeper strata, and has found its outlet below its original level. It is generally cool and fresh, containing little organic matter, but abundant mineral material. What may indicate sewage contamination of water, and what amount thereof is permissible in potable water ? Sodium chloride and other chlorides may indicate sewage con- taminations, but are no evidence thereof. Potable water should not contain more than two grains of it to the gallon. If more, the character and amount of organic material should be determined. Is there any chemical process giving the amount of organic material contained in water ? No ; the organic material in water can only be arrived at com- paratively by either converting it by an allsaline potassium per- manganate solution into ammonia, and determining this with the Kessler’s test, or by determining how much potassium per- manganate solution is necessary to oxidize it, and comparing this with the amount of oxalic acid necessary to the same end. What process may be employed to determine the amount of organic material ? The biological test in which sterilized gelatine solution is in- oculated with the water to be tested ; the number of colonies of bacteria developed are then counted and compared with those developed from known pure water. How is the amount of chlorides in water determined ? By testing the water either directly or after concentration with a volumetric solution of silver nitrate, using potassium chromate as an indicator. CHEMISTRY. 59 How is this done? One hundred c.c. of the water are placed in a beaker glass, a few drops of the potassium chromate solution are added to render it yellowish. The mixture is rendered slightly alkaline, and then from a burette the silver nitrate solution (4.79 grams per liter) is dropped into it until the water turns faintly orange- red. Each c.c. of the silver solution so used represents 0.001 chlorine in 100 water or 0.01 in the liter. What does the presence of nitrites in water indicate ? The decomposition of organic nitrogenized material, and any other but rain-water, containing them, should be regarded with suspicion. How can small amounts of nitrites in water be readily de- tected? By adding to it a solution of diplienylamine in pure strong sulphuric acid. If nitrites are present a blue color wiil be de- veloped. Also by adding to the water to be examined a few drops of II.4So4 and then some starch-water, and lastly a few drops of KI solution. If the starch turns blue nitrites are present. What is indicated by detecting in water an excess of chlorides and also nitrites ? That it is contaminated with sewage. Is an excess of chlorides alone, without organic admixture, or of nitrites alone without chlorides sufficient to condemn a water ? No, as water may, for instance near the ocean, contain a greater amount of chlorides, and rain-water generally contains nitrites. What are the best means for purifying water? Filtration to remove suspended matter and boiling ; because this destroys the disease germs and corrects temporal hardness. How is water tested for lead ? By evaporating a certain amount, treating the residue with IINOj, evaporating the excess of HNO„ dissolving the residue in a little distilled water and passing through it a current of hydro- 60 ESSENTIALS OF MEDICAL CHEMISTRY. gen sulphide. If lead is present (other metals of this group being excluded), a brownish-black precipitate will be noticed ; when lead exists in notable quantities, the water may be tested direct by hydrogen sulphide or an addition of ammonium sulphydrate. What are carbonated, alkaline, chalybeate, saline, and sul- phur waters ? Waters having special ingredients which meet therapeutic in- dications. Those containing an excess of carbon dioxide are termed carbonated, others holding in solution the carbonates of the alkalies are called alkaline ; saline waters those containing neutral salts in serviceable quantities; while the waters contain- ing hydrogen sulphide or alkaline sulphides in solution are sulphur waters, and when iron is contained in them they are called chalybeate. What is hydrogen peroxide? Its prcpeities? A colorless syrupy liquid, sp. gr. 1.45, formula H20.,, m. w. 34. It is a powerful bleacher and deodorizer, unstable when concentrated, less so when in dilute solutions (commercial 1-10). In decomposition it gives off'nascent oxygen. How is it prepared ? By decomposing barium peroxide with sulphuric acid or car- bonic acid. BaO, + II2S04 = BaS04 + II A- Electronegative Monads—Halogens. What elements belong to this group ? Chlorine, bromine, iodine, fluorine. Why are they also called halogens ? Because they are salt producers, i. e., they produce with the metals salt-like derivatives. CHEMISTRY. 61 Chlorine. What is chlorine ? A yellowish-green elementary gas of suffocating odor, symbol, Cl, a.w. 35.37, m.w. 70: 1 liter weighs 3.17 grams. Sp. gr. 2.46. What are its physical properties? It is coercible at 15° C. and 4 atmospheres pressure; freely soluble in water, 1 volume at 20° C. taking up two volumes Cl; this solution being known as chlorine water; this forms crystals of chlorine hydrate (CL, + 10 II,O), below 0°C., but decomposes into its constituents at ordinary temperature. Give its principal chemical properties. It has a great affinity for almost all elements forming chlorides with them. This often takes place amidst heat and light phenomena, as when Dutch metal leaf or powdered antimony is thrown into the dry gas. It decomposes with water and other hydrogen compounds into HC1 and O. It decolorizes indigo and litmus solutions, also other organic colors when moist, by liberating nascent O, and also destroys organic germs in this manner. What is meant by nascent 0 and by nascent state? Nascent O means O at the moment of liberation before it as- sumes its free or molecular state. The nascent state of bodies really implies their atomic or also unsaturated state. Is chlorine combustible or a supporter of combustion, and what occurs when a burning candle is immersed in chlorine ? It is not combustible but a supporter of combustion ; a burn- ing candle will continue to burn in it, giving off dense volumes of carbon. How is chlorine prepared ? By heating a mixture of manganese dioxide with hydrochloric acid or with the materials forming this latter, namely, chloride of sodium and sulphuric acid. 62 ESSENTIALS OF MEDICAL CHEMISTRY. Explain the former process by equation and also the latter. Mn02 + 4 HCl = MnCl2 + Cl + 2 H20 Manganese dioxide. Hydrochloric acid. Manganous chloride. Chlorine. Water. Manganous chloride being formed which dissolves in the water. The other process depends upon the formation of hydro- chloric acid and the decomposition of this by the manganese dioxide: 2ITaCl + H2S04 = Na2S04 + HCl. Again : MnO, + H2S04 + 2HC1 = MnSO* + 2H20 + Cl2. Sodium chloride. Sulphuric acid. Sodium sulphate. Hydrochloric acid. Manganese dioxide. Sulphuric acid. Hydrochloric acid. Manganous sulphate. Water. Chlorine. What is the compound of chlorine and hydrogen ? Hydrogen chloride or hydrochloric acid, formula HC1, m. w. 3(5.37, a colorless gas, sp. gr. 1.26, of pungent odor, fuming in the air, irritates the air passages, very soluble in water, 1 volume dissolving 450 volumes at 15° C., the solution being known as hydrochloric or muriatic acid. What is the acidum hydrochloricum U. S. and what acidum hydrochloricum dilutum TJ. S.? The former is a colorless solution of pure HCl in water, sp. gr. 1.16 ; the latter is the further dilution of the stronger to the sp. gr. 1.049, containing 10 per cent. HCl. What are the tests for the recognition of HCl? Its vapors redden moist litmus paper, and give dense white vapors with ammonia. What are further tests for HCl and soluble chlorides? They give white, curdy precipitates with silver nitrate, which are soluble in ammonium hydrate. Does free hydrochloric acid exist in the body, and where? Yes ; in the gastric juice. What is the character of the stain on textiles by hydrochloric acid? Hark textiles are generally stained red by it ; the stain is evanescent and readily removed by ammonium hydrate. CHEMISTRY. 63 State in brief its poisonous action. Its action on the tissues is that of a corrosive, producing extreme laryngeal irritation, even oedema and consequent asphyxia, black eschars on tongue and pharynx, corrosion and possibly perforation of oesophagus and stomach, and even in absence of this, it may cause subsequently inanition from destruction of mucous surfaces or stricture of the oesophagus. What are the antidotes for poisoning- by HC1 ? Alkaline carbonates in dilute solutions, alkaline earths, mag- nesia, and soap-suds. What class of poisons does it belong to, which are the principal ones of this class, and what is the mode of their toxic action ? It belongs to the corrosive acids, the principal ones of which are sulphuric, nitric, and hydrochloric acid ; they act by the destruction of the tissue they come in contact with, but not by absorption. How is the strength of acids quantitatively determined, and upon what is this process based? By acidimctry, wherein the acids are neutralized by alkaline solutions of known strength, termed volumetric solutions. How are the volumetric solutions of KOH and NaOH prepared ? By making solutions of these alkalies and standardizing them with a normal solution of oxalic acid, which contains as many grains of the latter in a liter of distilled water as one-half of its molecular weight. The alkaline solution must be made of such strength as to neutralize exactly the oxalic acid solution volume for volume. How is the process of acidimetry performed? A certain amount, say 10 c.c., of the solution to be tested is placed in a beaker glass, diluted, and to it are added a few drops of red litmus solution as an indicator; then the volumetric alkaline solution is dropped into the former until the change of color of the litmus to a violet indicates the neutralization. The result of the neutralization is then computed either by stoichio- 04 ESSENTIALS OF MEDICAL CHEMISTRY. metric proportion or by reference to already computed tables. When the acidity of mixed acids is wanted this is expressed in comparative amounts of oxalic acid. Which are the oxygen compounds of chlorine ? C1.20 hypoehlorous oxide or hypochlorous anhydride. CIA chlorous oxide or chlorous anhydride. CIA chloric oxide or chloric anhydride. CIA perchloric oxide or perchloric anhydride. What do they form with water respectively? C1.20 -f H20 = 2IIC10 hypochlorous acid. CIA + H20 = 2HC102 chlorous acid. C1205+II20 = 2HC103 chloric acid. CIA + = 2HC104 perchloric acid. Are these compounds stable? In what form are they princi- pally found, and what are those cf medical interest? They are unstable, and are generally found as salts of the acids, of which the hypochlorite of calcium Ca(C10)2, hypo- chlorite of sodium NaCIO, and the potassium chlorate KC103) are of importance in medicine. In what substance is calcium hypochlorite contained, and with what other substance? How prepared? In calx chlorata, chlorinated lime, also called chloride of lime, commonly known as bleaching powder, which consists of a mix- ture of calcium chloride CaCl, and calcium hypochlorite Ca(C10)2. It is prepared by saturating slaked lime with chlorine gas. What preparation depends upon the presence of sodium hypo- chlorite for its efficacy ? The liquor sodse chloratse or chlorinatse, otherwise known as Labarraque’s solution. It is prepared by decomposing a satu- rated solution of chlorinated lime with a solution of sodium car- bonate, the latter being in excess. It is a powerful disinfectant, as, in its decomposition, it gives rise not alone to chlorine, but to nascent O also. CHEMISTRY. 65 Bromine. What is bromine? Its physical properties? An elementary liquid, of dark reddisli-brown color, and dis- agreeable odor. Symbol Br, a. w. 80; sp. gr. 3.18 at 0° C. ; it crystallizes at —7.3° C ; boils at 63°, giving rise to yellowish- brown vapors ; at a lower temperature the vapors are dark- brown ; one part of it at 15° C. dissolves in 39 Aq. It is soluble in alcohol, but more so in ether, chloroform, and carbon bisul- phide. What are its chemical properties ? Very much like those of chlorine, but less active, bleaching like it, but in a less degree. It colors starch yellow. When and how does bromine occur in nature? In sea-water and in saline springs, termed bitterns, as bro- mides. How is bromine prepared ? Like chlorine, by warming a mixture of manganese dioxide, and sodium bromide with sulphuric acid. Mn02 + 2KaBr + 2H2S04 = MnS04 + Na2S04 -f Br2 + 2H20. What is the hydrogen compound of bromine ? Hydrogen bromide or liydrobromic acid IIBr. How is HBr made ? Its properties ? By decomposing Br in H20 with hydrogen sulphide, as fol- lows : Br2 + H20 + H2S = H20 + S + 2HBr ; also by decom- position of a bromide with sulphuric acid. It is a colorless gas fuming on contact with the air. What is strong and what diluted hydrobromic acid ? The strong is a concentrated solution of gaseous IIBr in water, which when diluted to contain 10 per cent. HBr, sp. gr. 1.044, con- stitutes acidum hydrobromicum dilutum of the Pharmacopoeia. Which of the oxyacids of Br are used, and in what form ? The hypobromous acid IlBrO, as sodium liypobromite in the Knop’s solution for determining urea, q. v. GG ESSENTIALS OF MEDICAL CHEMISTKY. Iodine. What is iodine ? Its physical properties ? A crystalline, elementary body of metallic lustre. Symbol I, a. w. 127; sp. gr. 4.95; fusing at 113° C. to a liquid, and boil- ing at 200° C., giving off dark-violet vapors. It is slightly soluble in water, more readily in alcohol; in this form, when of officinal strength, it is the tinctura iodi; it is readily soluble in ether, chloroform, and carbon disulphide, in the last two with violet color ; potassium iodide favors its solution in water. Give its chemical properties. These are similar to chlorine and bromine, but weaker ; it im- parts a blue color to starch. Where does iodine occur in nature, and how is it prepared? It occurs in mineral springs and sea-water. Seaweed contains it, and when burned is known as kelp, from which it is manu- factured by a similar process to that employed for chlorine and bromine ; the magnesium iodide and sodium iodide being mixed with manganese dioxide and warmed with II2S04. What is the hydrogen compound of iodine ? Hydrogen iodide or hydriodic acid HI. a colorless gas, which is very soluble in water ; prepared similarly as hydrobromic acid, by treating iodine in water with hydrogen sulphide. It enters into the syrupus acidi hydriodici of the Pharmacopoeia. Fluorine. What is fluorine, and its properties ? Probably an elementary gas. Symbol FI, a. w. 19. Of such strong affinity for almost all substances, that it cannot be ob- tained free. What is its principal compound, and from what is this ob- tained ? Its principal compound is hydrogen fluoride HF1, or liydrofluo- CHEMISTRY. 67 ric acid ; it is obtained by the action of warm sulphuric acid on fluor-spar, the calcium fluoride ; CaFl2-f-II.j304 = CaS04-|-2IIFl. What are the properties of hydrofluoric acid ? Is fluorine found in the human economy, and where ? The aqueous solution of the gaseous hydrofluoric acid is a color- less liquid, very corrosive, and attacking the tissues severely. It also attacks glass, and is used for etching it. Fluorine, as fluo- ride of calcium, is found in the enamel of teeth and in the bones. Electronegative Dyads. Which elements compose this group? Sulphur, selenium, and tellurium (properly oxygen also). Sulphur. What is sulphur ? A solid elementary body, capable of existing in several allo- tropic conditions. Symbol S11 Iv VI, a. w. 32. State the different systems of crystallization, and their char- acteristics. 1. The regular or tesseral system, the crystals of which have three axes of equal length, intersecting each other at right angles. 2. The quadratic or tetragonal system, the crystals of which have one longer and two shorter axes ; the latter of equal length and all intersect each other at right angles. 3. The hexagonal or rhombohedral system ; the crystals of this system have four axes, three of equal length, which inter- sect each other in one plane at angles of 60° ; the fourth, a longer axis, intersects their plane at 90°. 4. The rhombic system, the crystals of which are all of unequal length, and intersect each other at 90°. 5. The monoclinic system ; its crystals have three unequal axes ; two of which intersect at 90° ; the third intersects one at 90°, and the other obliquely. 68 ESSENTIALS OF MEDICAL CHEMISTRY. 6. The trielinic system comprises the crystals which have three unequal axes, all obliquely inclined to each other. What is the physical structure of the different allotropic con- ditions of sulphur, and how is their occurrence accounted for? 1st, ordinary octahedral or rhombic sulphur, sp. gr. 2.05 ; 2d, prismatic or monoclinic sulphur, sp. gr. 1.98 ; 3d, soft, plastic sulphur, sp. gr. 1.95. These different modifications may be ac- counted for by the presence of varying numbers of atoms in their molecules. What is the effect of different degrees of heat on sulphur ? It melts at 115° C. as a pale yellow liquid ; between 200° and 250° C. it becomes viscid ; above that it becomes fluid again and boils at 440° C. In what different forms does sulphur come in commerce ? Roll sulphur, sublimed sulphur, which, when washed free from adhering acids, is termed sulphur lotum ; precipitated or lac sul- phuris. Where and how does sulphur occur in nature ? It is found free in volcanic*, regions ; also as compounds with many metals as well as in organic substances. How does sulphur behave chemically? Similar to oxygen, forming binary compounds with most of the metals, burning in the air with bluish flame to form sulphur dioxide SO,, and it may also exhibit linking powers like oxj'gen. What is the hydrogen compound of sulphur ? Its properties ? Hyd rogen sulphide, also termed sulphuretted hydrogen, II.,S ; a gaseous colorless body of the odor of rotten eggs, sp. gr. 1.177, and coercible ; soluble 3-4 volumes in 1 of water. It is com bustible, weakly acid, and poisonous. How is H ,S prepared ? By the action of H2S04 on ferrous sulphide EeS. FeS+H2S04,=FeSOt+H2S. CHEMISTRY. 69 How is ferrous sulphide made? By fusing together iron filings and sulphur. What does H2S form with metals ? Metallic sulphides. Does H2S occur in the body? Where and how does it form ? It occurs in the body from decomposition of albuminous food in the flatus ; from the tartar of the teeth and from decay of food between them; it gives rise to the blue liue on the gums in lead poisoning. How does H2S act as a poison ? By combining with and reducing the haemoglobin. Where does it occur, and what symptoms does it give rise to when inhaled for some time? In sewer gas, the inhalation of which for some time gives rise to giddiness, headaches, and low fevers. What are the antidotes for H2S poisoning? Stimulants, fresh air, and chlorine. What are the tests for H2S ? Its characteristic odor and moist lead acetate paper, by which 1 in 10,000 can be detected. What are the principal oxygen compounds cf sulphur ? Sulphur dioxide, sulphurous oxide So.2, and sulphur trioxide, sulphuric oxide So3. What is sulphur dioxide and its principal properties? A colorless gas of pungent suffocating odor, SOv, m. w. 04, sp. gr. 2.247 ; coercible at —15° C. or at ordinary temperature, and two atmospheres of pressure, crystallizing at — 70° C.; 50 volumes soluble in 1 volume water; neither a supporter of combustion nor combustible. What are its principal chemical properties? It unites with II20 to form sulphurous acid, H2S03; is a reduc- ing agent, i. e., has great affinity for oxygen. 70 ESSENTIALS OF MEDICAL CHEMISTRY. What is the sulphurous acid II. S. ? A solution of II2S03 in water, of the characteristic odor of burning sulphur, sp. gr. 1.022-1.023, and of strongly acid reac- tion. For what purposes is S02 employed, and how? To put out fires, bleach, reduce oxygen compounds, and as a germicide. For disinfecting purposes sulphur is burned in a closed room ; about 2 pounds are used for 1000 cubic feet of floor room. How is S02 prepared? By burning sulphur in oxygen or in atmospheric air, S2+0 4=2S02, also by the action of II2S04 either on copper or charcoal, sulphur dioxide being liberated, and in the latter pro- cess also C02. 2H2S04+Cu=CuS04 + S02-f 211,0, also, 2H2S04+C=C02+2S0.rf2H20. What is sulphuric oxide or sulphur trioxide? A white solid, crystallizing in silky needles S03, which unites with H.20 to form H2S04 ; it has no acid properties. What is sulphuric acid ? A dense colorless, inodorous, corrosive liquid H2S04, m. w. 98, sp. gr. 1.84, containing not less than 96 per cent. H.,S04. The acidum sulphuricum dilutum U. S. contains 10 per cent. H.,S04, sp. gr. 1.067. The commercial I12S04 is known as oil of vitriol. State some of the principal properties cf HSO,. It is a dibasic acid forming two salts with monad metals, which if H is present are termed acid, or if two metallic atoms normal salts. It has a great attraction for water, evolving heat when mixed with it; on this account it is used for drying gases and precipitates. Give in brief the process for the manufacture of H.2S04. This may he stated as taking place in four stages. 1. The formation of sulphur dioxide by burning sulphur or pyrites with access of air. S-[-02=S02. CHEMISTRY. 71 2. Generating nitrogen tetroxide N204, which gives off oxygen to the S02 forming S03 and N202, 3. The S03 is mixed with aqueous vapor resulting in the formation of II2S04, as follows: 2S02+N204=2S03-}-NA* so3+h2o=h,so4. While, 4tli, the N202 is reoxidized by contact with the oxygen of the air, na+o2=na, and can be used again as before, the whole of the process being conducted in leaden chambers ; the resulting liquid is condensed to the proper specific gravity. What class of poisons does H,S04 belong to, and what are the symptoms caused by it ? It belongs to the corrosive mineral acids, causing white eschars on tongue, lips, and pharynx, possibly oedema of larynx and per- foration of stomach, and, if not, the patient may die of inanition eventually. What are the antidotes for poisoning by sulphuric acid ? Magnesia, alkaline carbonates, soap-suds, also eggs and milk. What are the tests for sulphuric acid ? Red stains on dark textiles, disappearing on application of ammonium hydrate. II,SO, and the soluble sulphates give dense white precipitates with barium chloride or nitrate; when con- centrated down II,jS04 will char the carbohydrates. Paper moistened with a diluted II2S04, and the water evaporated by gentle heat will char. Concentrated II.,S04 heated with copper slips will liberate vapors of sulphur dioxide. What is hyposulphurous acid, and what is sodium hyposulphite? Hyposulphurous acid H2S02, an unstable compound ; the so- called sodium hyposulphite Na2S203 is really not a hyposulphite but a thiosulphate. 72 ESSENTIALS OF MEDICAL CHEMISTRY. What is Nordhausen or fuming sulphuric acid? A thick, oily, fuming liquid, sp. gr. 1.85-1.9, sometimes called disulphuric acid, because its formula may be obtained from two molecules of II2S04 by the subtraction of H20 ; 2I12S04—II20= H2S207. It splits up by heat into II2S04 and S03, so that it may be considered a solution of S03 in II2S04. It dissolves indigo. Electronegative Triads or Nitrogen Group. Which elements belong to this group ? Nitrogen, phosphorus, arsenic, antimony, bismuth Nitrogen. What is nitrogen ? An elementary gas, symbol N1111 v, a. w. 14, sp. gr. 0.971 •, one liter weighs 1.25 grams. What is it also called, and where does it occur free? It is also called azote, and occurs free in the atmosphere, of which it constitutes about four-fifths. Give the properties of N. It is colorless, odorless, tasteless ; coercible only at —130° C. and 280 atmospheres ; it is neither combustible nor a supporter of combustion ; it combines directly with very few substances ; it extinguishes flames and life when immersed in it. How can nitrogen be prepared ? By isolating it from the air by burning phosphorus in a closed vessel; also by decomposing ammonium nitrite by heat as fol- lows :— NH4N02 = + 2H20. Ammonium nitrite. Nitrogen. Water. What is the atmosphere ? A gaseous envelope surrounding the earth, composed of a mechanical mixture of oxygen by volume 20.8 and nitrogen 79.2 in 100 volumes. It contains, besides a little C0.2, some aqueous CHEMISTRY. 73 vapor, also traces ofNII3, CH4, II2S, S02; the proportions ofN and O are very constant. State the probable height of the atmosphere and the pressure exerted by it on the square inch. The height of the atmosphere has been variously computed from 50-150 miles. It exerts a pressure of 15 pounds to the square inch. How can atmospheric pressure be demonstrated? By filling a glass tube over 30 inches in length with mercury and reversing it while immersed in a vessel of mercury ; the column of mercury in the tube will at once fall to about 30 inches or 760 millimetres ; this column is counterpoised by the atmos- phere, and there will be a vacuum above it. What instruments are based upon this, and how are they con- structed ? Barometers for measuring atmospheric pressure. They are glass tubes closed at the top and ending in a cistern or syphon of mercury. They have attached to the tube a scale for measur- ing the height of the column of mercury. State the cause of variable atmospheric pressure. Storms, changes in the meteorological condition, and increased or decreased altitudes. How does atmospheric pressure affect the volume of gases? Greater pressure diminishes their volume and diminished pres- sure increases it. What other factors influence the volume of gases, and how ? Heat increases their volume, cold diminishes it. What has to be done to compare volumes of gases, and how is this done ? They have to be reduced to a common standard at 0° C. and 760 mm. pressure. This can be accomplished by the following formula :— y_v-_P- ~ 7(50 (1+0.003661.) 71 ESSENTIALS OF MEDICAL CHEMISTRY. V stands for the volume wanted at 0° C. and .760 mm. pres- sure ; v. for the observed volume ; p. for observed pressure ; t. for observed temperature, while 0.00366 is the coefficient for the ratio of expansion of gases by heat. What is the compound of nitrogen and hydrogen ? Ammonia NH„ m. w. 17 ; one liter weighs 0.762 grams. Give the principal properties of ammonia. It is a colorless gas of pungent odor, sp. gr. 0.59, coercible at 6.5 atmospheres pressure at 10° C. or without pressure at —40° C.; one volume of water absorbs at 0° C. 760 mm., 1050 volumes NH3 ; it is not combustible nor a supporter of combustion. It unites with acids directly forming pentad nitrogen compounds. See Ammonium. How is NH:i obtained, and how prepared ? It is obtained free from the ammoniacal liquor of gasworks, and may be prepared by the action of quicklime CaO on ammonium chloride NII4C1. 2NII4Cl+Ca0=CaCl,+n20+2NH3. Give the names and formulse of the oxygen compounds of nitrogen. Nitrogen monoxide N20, a colorless gas. Nitrogen dioxide N202, a colorless gas turning red with O or atmospheric air. Nitrogen trioxide, nitrous anhydride N20.„ a dark blue liquid. Nitrogen tetroxide N20„ a yellowish-brown liquid or gas. Nitrogen pentoxide, nitric anhydride N205, a white crystalline solid. What is nitrogen monoxide ? This is a colorless gas of sweetish taste and slight odor, some- times termed nitrous oxide, also laughing gas, N20, m. w. 44 ; one liter weighs 1.97 grams ; sp. gr. 1.527 ; coercible with 30 atmospheres pressure at 0° C. It is a supporter of combustion, inflaming glowing embers immersed in it as in oxygen. CHEMISTRY. 75 How is N20 produced ? By the decomposition of ammonium nitrate by heat. What is its physiological effect, and for what purposes used ? It produces first exhilaration, then anaesthesia and asphyxia. It is used as an anaesthetic for short operations, for which it is regarded as quite safe. What is nitrogen dioxide ? A colorless gas N202, m. w. 60 ; one liter weighs 1.34 grams; sometimes called nitric oxide, sp. gr. 1.038, coercible, slightly soluble in water, forms with O or atmospheric air brown vapors of nitrogen tetroxide N204. How is N202 prepared, and for what used? By the reduction of nitric acid by metals, such as copper, Cu;!+8nN03=3Cu(N0.j)2-{-4H20-|-N20.; ; it may be employed to detect oxygen in gases. What is nitrogen trioxide ? A dark blue liquid boiling at 0° C., N.,0:1, m. w. 76 ; it forms with water nitrous acid, N203-f-H.,0=2HN02, which forms ni- trites with bases. Describe nitrogen tetroxide and its use. A yellowish-brown liquid or brown vapor at ordinary tempera- ture ; N204 resulting when N202 is exposed to the air. It is an oxidizing agent, used in converting II2SO:j into II2S04. State what results when nitrogen pentoxide unites with water, and give character of product. Nitrogen pentoxide forms with water nitric acid, N205-f-H20 =211 NO.,, a colorless, fuming, corrosive acid liquid, m. w. 63, sp. gr. 1.52. How is nitric acid prepared ? By the action of sulphuric acid on a nitrate. NH4N03=N,0+2H,0. Sodium nitrate. NaN03 + H,S04 = UNO, + NallSO, Sulphuric acid. Nitric acid. Acid sodium sulphate. 7G ESSENTIALS OF MEDICAL CHEMISTRY. What are the chemical properties of HN0:!? It is a monobasic acid of great oxidizing power, coloring organic nitrogen compounds yellow, and converting others, such as glycerin, cotton, etc., into explosives of great force. What is fuming nitric acid? What the acidum nitricum U. S., and the acid, nitric, dil. U. S.? Fuming nitric acid is a nitric acid containing nitrogen dioxide in solution. Acid, nitric. U. S. a colorless nitric acid, sp. gr. 1.42, containing 69.4 percent. IIN03. Acid, nitric, dilut. has a sp. gr. 1.039, and contains 10 per cent. IIN03. What is the effect of HN03 as a poison ? The same as the other corrosive mineral acids, with the only difference that the eschars are yellow. Give the tests for nitric acid and for nitrates, Niti'ic acid gives yellowish-red stains on dark textiles, not removable by ammonium hydrate; it colors blue litmus red, darkens ferrous sulphate in presence of sulphuric acid, bleaches indigo solution, gives rise to red vapors with copper slips, and gives a red color on addition of brucine. The nitrates are recog- nized by the same tests if the HN03 is first liberated by H2SG4. What is nitro-hydrochloric acid? A mixture of 3 parts of HNO;i and 5 of HC1, also called aqua regia, as it dissolves gold and platinum, which neither alone effects. This is due to free chlorine and chlorine derivatives (nitroxyl chloride N02C1 and nitrosyl chloride NOC1). Phosphorus. What is phosphorus ? A waxlike, colorless, or slightly yellow, semi-transparent ele- mentary solid, luminous in the dark. Symbol P1 1,1 v, a. w. 31, m. w. 124, vapor density G2, sp. gr. 1.83, melts at 44° C. to a colorless liquid, boils at 290° C. It occurs in two allotropie states. How is the molecular weight of bodies obtained? By multiplying their vapor density by two. CHEMISTRY. 77 What are some of the principal physical properties of phos- phorus? It is soft and tough at ordinary temperature, insoluble in water, soluble in ether and alcohol, very soluble in carbon di- sulphide, from which it crystallizes in rhombic dodecahedra. Describe what two principal allotropic modifications of phos- phorus there are, and what properties has the second. The one is yellow and the other is dark-red ; the latter is called amorphous ; the red is insoluble in carbon disulphide, is not luminous, is not poisonous, and does not melt. How is red phosphorus prepared from the yellow? By heating the yellow in an atmosphere of C02 to 300° C. State the chemical properties of phosphorus. It has a great affinity for O, combining with it at a compara- tively low temperature, and for that reason has to be kept under water. It also combines with II and Cl, Br and I. Where and how does phosphorus occur? It is not found free in nature, but as phosphates. Its principal source is the calcium phosphate of bones. What is one of the technical uses for phosphorus ? In the manufacture of friction matches, for which the red variety is preferable as less injurious to the operators. It is also used in rat poisons. What is the local action of phosphorus ? When handled carelessly it ignites, causing severe burns and sloughs, not infrequently accompanied by systemic intoxication. What are the results of inhaling its fumes for some time, as in match factories ? Chronic poisoning, resulting frequently in maxillary necrosis. State the symptoms of acute poisoning by phosphorus. It is an insidious poison, killing sometimes soon after inges- tion, but frequently only for some time after with symptoms of acute, yellow atrophy of liver, jaundice, suppression of urine, delirium, uraemia, and coma. 78 ESSENTIALS OF MEDICAL CHEMISTRY. What is the treatment for and what is the antidote to poisoning by phosphorus? Stomach pump, cupric sulphate as emetic, which is antidotal as well, rendering the phosphorus non-assimilable as copper phosphide, also old spirits of turpentine. How can the lucifer disease in match factories be prevented? By good ventilation, and having oil of turpentine placed openly about the work-rooms, and worn in cloths or sponges around the necks of operators, but principally by the employment of the red variety only. What is a good test for phosphorus? By boiling the substance suspected to contain it in acidulated water, and allowing the vapors to strike a paper containing silver nitrate, which is colored dark by the formation of silver phos- phide. Explain the principle of Mitscherlich’s test for phosphorus. It is based upon the distillation of the substance suspected to contain phosphorus from acidulated water, when, upon striking the cool surface of the condenser, it will give rise to luminosity at that point if viewed in the dark. Alcohol, ether, oil of tur- pentine, and other essential oils interfere with this test. In examining vomited matter or a stomach suspected to contain phosphorus, what should be dene ? It should be inspected in the dark for luminosity, and also be examined for its characteristic odor. What is phosphine ? A hydrogen compound of phosphorus, termed hydrogen phos- phide PII3, in. w. 34. It is a colorless gas, with a garlicky odor. It ignites at about 100° C., is poisonous, and is sometimes liber- ated in marshes, when it is known as the ignis fatuus or Will- o’-the-wisp. Give the oxygen compounds of phosphorus. Phosphorus trioxide P203 and phosphorus pentoxide P2Os. CHEMISTRY. 79 Which are the direct acids of phosphorus? Hypophosphorous acid H3PO„ the oxide of which has not been isolated. Phosphorous acid derived from P2Os-(-3H20 = 2H.4P03. Phosphorous pentoxide yields with water orthophos- phoric acid H3P04, as follows : P205 -f- 3H20 = 2H3P04. What are the other phosphoric acids, and how derived? By the abstraction of one molecule of water from respectively one or two molecules of H3P04, the meta- and pyrophosphoric acids are formed as follows :— HsP04 — H20 = IIP03 or metaphosphoric acid. 2II3P04— II20 = H4P207 or pyrophosphoric acid. State the salts respectively formed by the different phosphoiic acids. Hypophosphorous acid forms hypophosphites, phosphorous acid phosphites, orthophosphoric acid orthophosphates, meta- phosphoric acid metaphosphates, and pyrophosphoric acid pyro- phosphates. What salts are formed by the orthophosphoric or tribasic phos- phoric acid ? Three different kinds of salts,'according to the number of II atoms displaced. Thus the mono-sodium or acid sodium phos- phate NaII2P04 as found in the urine ; di-sodium or neutral so- dium phosphate Na2HP04 as found in the blood*; also the hydro- calcium phosphate Ca (II,P04)2, and the normal calcium phos- phate Ca., (Po4)2 of the bones. Besides these, double salts may be formed by a univalent and a divalent atom together displacing the three II as in ammonium-magnesium phosphate NII/Mg"- P04. Which is the acidum phosphoricum of the XT. S. Pharmacopoeia, and what the test for it? The orthophosphoric acid H3P04, recognized by giving a yel- low precipitate with silver nitrate when neutralized with ammo- nium hydrate, and by giving a white precipitate with the mag- nesium mixture. These tests apply equally to its salts. 80 ESSENTIALS OF MEDICAL CHEMISTRY. What is arsenic ? A steel-gray crystalline, elementary solid, of metallic lustre. Symbol As111 v, a. w. 75 ; sp. gr. 5.7, m. w. 800 (a second amor- phous variety of black color, has a sp. gr. of 4.71); volatilizes at 180° C. without fusing, giving rise to yellowish-brown fumes of garlicky odor. It gradually oxidizes in the air, and burns at red heat with blue flame to form arsenious oxide. How is arsenic found in nature? Sometimes in its free state, but generally as a compound of other elements, such as sulphur or oxygen (As.20:)) and the metals Fe and Co. It is separated from its oxide by heating with charcoal As.203 -f- 3C = 2As -+- 3CO. What is the technical use of arsenic ? In fireworks, the manufacture of shot, and as fly-powder, under the name of cobalt or fly-stone. Describe the hydrogen compound of arsenic. Hydrogen arsenide or arsine, also called arseniuretted hydro- gen, a colorless gas of garlicky odor AsH3, m. w. 78, sp. gr. 2.7 ; it is very poisonous. What are the chemical properties of AsH:i ? It burns in the air with a bluish flame, to arsenious oxide As203. If its combustion is interfered with by introducing into its flame a cold surface of porcelain, it deposits thereon a brownish- black stain of elementary arsenic. If heated to redness in a glass tube conducting it, it deposits a mirror-like ring of elementary arsenic beyond the flame. It decomposes solutions of silver nitrate into metallic silver, forming arsenious acid. How is hydrogen arsenide formed and prepared? By the action of nascent hydrogen on arsenical compounds, also by the action of moist air and organic compounds on arsenical pigments. It is principally prepared by generating hydrogen in the presence of arsenious oxide as follows :— Arsenic. GZn + 6H,S04+As20a=6ZnS04+3II/)+2AsII3. CHEMISTRY. 81 What compounds does arsenic form with oxygen? Arsenic trioxide or arsenious oxide As20.), and arsenic pent- oxide or arsenic oxide As205. In what forms does arsenic trioxide occur? It occurs in two varieties, the vitreous or amorphous as trans- parent glassy masses, sp. gr. 3.78, which gradually change to the non-transparent or porcelainous variety of crystalline structure, sp. gr. 3.59. The commercial variety comes in powder form and is called white arsenic. State the properties of As,03. It volatilizes at 218° C., is white or colorless, odorless, is only slightly soluble in cold water, about 1 to 2 parts per 1000, more readily soluble in boiling water, and after boiling for one hour 50-80 parts dissolve in 1000. (Aqua Tofani.) What is the action of HN0:i cn As 0f ? It gives up O to the As203 and forms As205. What do the oxides of arsenic form with water ? Arsenic trioxide forms with water arsenious acid, As20:j ~f- 3H20=2HaAs0 . Arsenic pentoxide forms arsenic acid. As2Os 4-3II20=2II3As0j, both giving acid reactions. Name the respective salts of arsenious and arsenic acid. Arsenites and arseniates. Which are the principal compounds of arsenic with the halogens ? Arsenic trichloride AsC13, a colorless oily liquid. Arsenic tribromide AsBr3, a white crystalline substance. Arsenic tri- iodide AsIo, red crystals. What are the sulphur compounds of arsenic ? Arsenic trisulphide As2S.t when As20:t is precipitated by II2S ; it also occurs in nature as auripigment or orpiment or king’s yel- low, and is used as a yellow pigment, also as a depilatory. There is also an arsenic pentasulphide As2S-, and an arsenic disulphide As,S2 ; the latter exists in nature, and under the name of realgar is used as a red pigment. 82 ESSENTIALS OF MEDICAL CHEMISTRY. Name the Pharmacopceial preparations of arsenic anl their strength. Liquorpotassii arsenitis, Fowler's solution, 1 As.,0,, and 1KHC03 in 100 water with compound spirit of lavender. Liquor acidi arseniosi, solution of arsenic chloride, containing 1 part As20:) and 2 parts HC1 in 100 water. Liquor arsenici et hi/drdrgyri iodidi, Donovan's solution, contain- ing 1 part AsI3 and lllgl2 in 100 water. Liquor sodii arseniatis, solution of sodium arseniate, Pearson's solution, 1 part anhydrous sodium arseniate in 100 water. What is Scheele’s green, and what Paris green ? Compounds of arsenious acid and copper, frequently used with homicidal intent, and employed to destroy insects. Do wall papers contain arsenic, and in what quantity? Many contain arsenic in quantities from 1 to 50 grains to the square yard. This is not confined to low priced paper or those of green color alone. Is arsenic found in textiles, etc., anl how may it prove injurious in this way ? It is found in various textiles, prints, cretonnes, tarlatans, etc., and may give rise to poisonous symptoms by direct absorption as well as by inhalation of AsH3 produced from the reduction of the As203 therein. In what manner does arsenic prove poisonous ? Elementary arsenic is probably not poisonous as such, but by- oxidation it becomes so. As flv-stone or fly-paste it becomes poisonous by oxidation to As203. How is AsH, as a poison ? It is the most poisonous of all As compounds, on account of its rapid absorption by the lungs. Which is the most common poisonous compound of As ? As203, contained in the ratbanes of the market; its smallest poisonous dose is two grains; but recovery has been known to take place after ingestion of two ounces ; chances appear better for recovery after large doses than small ones, as they are more CHEMISTRY. 83 promptly ejected. Fowler’s solution taken in overdoses frequently proves a source of poisoning; children appear less susceptible than adults. What is the toxic action of arsenic compounds ? They are irritants but not corrosives; ulceration results from irritation and inflammation indirectly, therefore the stomach- pump may be used in the earlier stages but not later on. Inflam- mation may also be found in the intestines, peritoneum, and bladder, but principally in the duodenum, oesophagus, pharynx, and the mouth may also be inflamed from vomiting. What are the preserving powers of arsenical compounds? Cadavers are preserved by them, and thus marked preservation of an exhumed body would direct suspicion to arsenical poi- soning. Give the symptoms of arsenical poisoning. They come on in from a half hour to ten hours; if early, chances for recovery are more favorable. Symptoms : austere me- tallic taste, fetid breath, constriction of pharynx and oesophagus, sinking sensation with great preecordial pains, retching and vomiting, intense thirst, but drinks ai’e not tolerated no matter how bland ; darting, shooting pains in colon, colitis, dark bloody stools, small thready pulse, cold skin, pinched nose, collapse, eruption of skin may breakout in a few days, sensation benumbed, paralysis, tetanic spasms, delirium, prostration, and death. Are all cases alike? Not always ; patient may die, as in cholera morbus or in Asiatic cholera, with suppression of urine and without gastric irritation, and the general symptoms may vary greatly. What are the symptoms of slow arsenical poisoning ? Nausea, occasional vomiting, colitis, fever, debility, conjunc- tivitis, oedematous eyelids, ptyalism, alopecia, and brown pig- mentary spots on skin. What is the treatment for arsenical poisoning ? Evacuate the stomach by favoring emesis with warm water or warm milk or even zinc sulphate ; give demulcents such as eggs 81 ESSENTIALS OF MEDICAL CHEMISTRY. and milk, and then give the chemical antidote, ferric hydrate in tablespoonfuls every 5-10 minutes, or in place of it dialyzed iron, which, however, is not so reliable. How is ferric hydrate prepared? What its other name, and what its action as an antidote? Ferric hydrate or hydrated oxide of iron can be prepared in different ways. It may be prepared by completely precipitating the solution of a ferric salt with ammonium hydrate and wash- ing the resulting precipitate. A better preparation is the ferri oxidum hydratum cum magnesia, resulting by precipitating tinct. ferri chloridi fsiij with magnesia calciuata 3ij. The mixture of these diluted with water should be exhibited freely. In absence of magnesia a solution containing one ounce of sodium carbonate may be substituted for it. When magnesia is used the reaction is as follows : Fe2O(i-t-3Mg0 -f 3H20=Fe2(OII)6-f-3MgClr The action of the antidote on arsenic trioxide may be demonstrated as follows : 2Fea(0H)6+As,03=Fe.42As04+5H.p+Fe(0H),, i. e., the arsenic trioxide will be converted into an inert ferrous arseniate. Describe the test for arsenic when found in substance. Place the particles found in a small reduction tube and heat, when it will be sublimed in the cooler portion of the tube as octahedral crystals. If the particles are covered with flux (a mixture of equal parts of dry sodium carbonate, and potassium cyanide), or with charcoal, the As.,0., will be reduced, and an arsenical mirror will form in the cooler portion of the tube. To confirm the character of the mirror, heat the mirror with access of air, when it will sublime in the cooler portion of the tube as a white ring, which, under the microscope, will be found composed of the octahedral crystals of As203. What is necessary in testing for arsenic ? The test has to be confirmed in as many ways as possible. How are solutions suspected to contain arsenic to be tested ? Acidulate them with a few drops of IIC1, and treat with H2S. If arsenic is present, a lemon-yellow precipitate will be thrown down ; this is not soluble in cold IIC1, and should be further CHEMISTRY. 85 tested after filtration and drying by reducing it with flux, and producing the arsenical mirror and the white ring of octahedral crystals. What is Fleitmann’s test for arsenic ? This depends on the fact that zinc or aluminium produces II with KOH or NaOII ; the former at the boiling point, and the latter at ordinary temperature. If, after generating the II, the purity of the materials is tested by placing a piece of filtering paper moistened with AgN03 over the test-tube containing them, and this is not discolored by it, a few drops of the suspected liquid are added, when, if arsenic is present, the paper contain- ing the AgNO;) will present a dark stain ; the presence of II.2S or sulphides should, however, first be excluded by testing the liquids with a solution of a lead salt. This test, while convenient as a preliminary test, is not conclusive evidence. It does not give any reaction with antimonials. Describe some other tests for arsenic in solution. Ammonio-sulphate of copper will give a bright-green precipi- tate with arsenical solutions, and ammonio-nitrate of silver a yellow precipitate. Neither of these precipitates is conclusive, and should be reduced with flux to give the mirror and subsequent white ring of octahedral crystals. What is Reinsch’s test for arsenic ? Describe it. The test by which arsenical compounds are reduced with me- tallic copper. To that purpose the purity of the copper and HCl should first be tested by boiling the copper slip or gauze in di- luted IICl. If, after boiling, the copper does not tarnish, add some of the suspected liquid and boil again. If arsenic is pre- sent, the copper will be coated with elementary arsenic. This can be demonstrated by drying and rolling up the copper slip, and heating it in an open glass tube. If it is As, there will appear in the cooler portion of the tube the characteristic white ring of octahedral crystals of As./).,. What other substances may deposit on the copper in this test ? Sb and ilg may also deposit on the copper in Reinsch’s test, 86 ESSENTIALS OF MEDICAL CHEMISTRY. but they will give respectively amorphous or metallic globular sublimates. How can Reinsch’s test be made quantitatively ? By gradually inserting into the boiling acid mixture pre- viously weighed pieces of copper until they are no longer coated ; they are then dried and weighed ; the increase in weight giving the amount of As in the quantity of liquid employed. What are the advantages and disadvantages of Reinsch’s test ? The advantages are that it can be made in the presence of organic matter; that it is very delicate, and can be made quan- titative as well. Its disadvantages are that it is not available for arsenic acid or arseniates without previous reduction. Describe Marsh’s test for arsenic. This depends upon generating II from pure zinc with pure HaS04 from a suitable apparatus; the purity of the materials and apparatus being tested by allowing the hydrogen to burn for some time, and testing with a cool porcelain surface inserted into the flame. If no stain is thus produced, introduce some of the suspected liquid through the funnel tube, and again test the flame with the porcelain ; if a stain results, arsenic may be pre- sent, the flame in this case will be blue, and if the conducting tube is heated to redness in its course, a mirror will form in the tube beyond the flame. What are the advantages and disadvantages of Marsh’s test ? Its advantages are that arsenious acid, arsenites, arsenic acid, and arseniates can be detected by it; its disadvantages that it cannot be employed in the presence of organic material, which must first be destroyed by KCflCX, and 1IC1, and that it shows antimony as well as arsenic. How can the stains of As and Sb on the porcelain produced by Marsh’s test be differentiated ? Arsenic stain is instantly soluble in NaCIO, antimony is not; As stain dissolves slowly only in NIIJIS, Sb instantly ; As stain dissolved in HNOa and evaporated gives a brick-red stain with AgN03, Sb does not. The mirror in the tube, if As, is beyond the CHEMISTRY. 87 flame; if Sb, nearer and on either side of the flame, and may be differentiated as above. What is the comparative sensitiveness of Reinsch’s and Marsh’s test? Ileinsch’s shows grain ; Marsh’s 5(5jh—H20=HBo2) forming meta-boric acid HB02; heated to 140° C. it forms tetra- boric acid II2B407. What is the principal salt of H ,B,07 ? Its sodium salt termed borax Na2B,07, which occurs in nature and finds large application in medicine and the arts. 90 ESSENTIALS OF MEDICAL CHEMISTRY. Electronegative Tetrads or Carbon Group. What elements constitute this group ? Carbon and silicon. What is carbon ? An elementary solid, CIr * IV, a. w. 12, occurring in three prin- cipal allotropie modifications ; it is not fusible nor volatile. What are the principal forms carbon is found in? Diamond, a crystalline substance of the monometric system, of great lustre and hardness, sp. gr. 3.5, bad conductor of heat and electricity, combustible at intense heat to COr Graphite, a leaden gray, usually amorphous, substance of unctuous touch, sp. gr. 2.25, good conductor of heat and elec- tricity ; occasionally found crystalline in hexagonal plates, com- bustible with difficulty ; it is sometimes termed plumbago, and used for making lead pencils. Amorphous carbon, the product of incomplete combustion of organic bodies; also found in the fossil state. Name the different varieties of amorphous carbon. Soot or lampblack, vegetable coal or charcoal, animal coal or boneblaek, gas carbon or plumbagine, bituminous or soft coal, also cannel coal, coke, and anthracite or hard mineral coal. Describe lampblack and its use. The carbonaceous matter condensed from the incomplete com- bustion of resins and hydrocarbons, etc., a finely divided form of carbon used for making printing and marking inks. Describe charcoal and its use. The product of incomplete combustion of wood, has a black color, is odorless, tasteless, sp. gr. 1.7 ; it is very porous, and can absorb many gases and vapors (90 volumes NH3, 55 H.2S, 9 02) ; it is a powerful disinfectant. When saturated with one kind of gas it can still take up others; it contains condensed oxygen which can oxidize decaying matter and decolorize organic colors. Carbon. CHEMISTRY. 91 Describe animal charcoal, its manner of purification and use. A similar production from bone as charcoal from wood ; it is purified by treating it with HC1, and used as an antidote for alkaloidal poisons, which it absorbs. Describe gas carbon and its use. The carbon deposited in gas retorts, very hard, of metallic lustre, good conductor of electricity, therefore used in galvanic batteries. Describe the principal varieties of mineral coal. Fossil coal in its different varieties containing C, FT, II, O, and S, besides mineral ash. Bituminous coal is rich in hydro- carbons, and when incompletely combusted leaves coke. Anthra- cite is the purest variety of mineral coal, is a good conductor of heat, and contains about 96-98 per cent, of pure C. What are the compounds cf carbon with hydrogen, and under what head are they generally considered ? Hydrocarbons, which, together with their derivatives, are gene- rally considered under the head of organic chemistry. (See Hy- drocarbons and their derivatives.) Which are the oxygen compounds of carbon ? Carbon dioxide C02, carbon monoxide CO. What is carbon dioxide, and what else is it called ? Carbon dioxide, CO.,, also termed carbonic anhydride or car- bonic acid gas, is a colorless gas of slightly pungent odor and acid taste. State the physical properties cf C02, It is heavier than air, sp. gr. 1.524, and can therefore be poured from one vessel to another; it will dissolve in equal volumes of water without pressure and much more with pressure. It condenses under a pressure of 36 atmospheres at 0° C. to a colorless mobile liquid, which, when allowed to evaporate, leaves portions of the C02 as a snow-like solid. What are the chemical properties of C02 ? It is neither combustible nor a supporter of combustion, unites 92 ESSENTIALS OF MEDICAL CHEMISTRY. with water to form carbonic acid, C02-|-II20==II2C03, which forms carbonates with the bases, is dibasic, and produces both acid and normal salts. K0H+H2C03=KHC03+H20 ; also : 2KOII+H2C03==K2C03+ 2H.O. How is C02 prepared ? By the decomposition of carbonates by acids. In the gazogenes by tartaric acid and sodium bicarbonate, similarly in the effer- vescent powders of the Pharmacopoeia, but for laboratory use or the manufacture of carbonic acid waters by the decomposition of marble (calcium carbonates), with hydrochloric or sulphuric acid. CaC03+2HCl=CaCl2+H,0+C02. Is Co* found in nature and where ? How dees it result ? It is found in nature as resulting from the direct combustion of carbon, also the decomposition of CaC03 by heat to form lime (CaC03=Ca0-j-C0!i), as resulting from terrestrial exhalations in caves and mines, when it is called choke-damp ; it also results from fermentation in cellars and brewery vats ; it is found free in the atmosphere in the proportion of about 0.05 per cent, volume. Where else does Co2 result from, in what amounts, and how can its presence be proven ? C02 also results as a consequence of the oxidation of the food and tissues in the body, and is exhaled as waste product by the lungs, the respired air containing about 4 per cent, volume. Its presence can be proven by breathing into lime water (calcium hydrate Ca(OII)2), which will be rendered turbid by the insoluble CaCO;j formed ; this will be redissolved by an excess of H2COs. How is C02 principally used in medicine and dietetics ? As carbonic acid waters or sparkling wines impregnated with CO,2 under pressure ; it imparts to them a refreshing, biting, sparkling taste, and acts as sedative to the gastric mucous mem- branes ; also in malt liquors where it results from fermentation. CHEMISTRY. 93 What is the effect of pure carbon dioxide when inhaled? It produces spasm of the glottis. When diluted with atmospheric air how does it act, and what amount of dilution will produce this effect ? It will asphyxiate persons even when as little as 5 to 8 per cent, is contained in the atmosphere. How is C02 detected in caves, wells, vats, etc. ? By lowering a lighted candle into them, which, if over 10 to 12 per cent. C02 is present, will be extinguished. If it burns dimly even, it is unsafe to descend into them, as the candle will burn where man cannot live. What is the amount of CO, in the atmosphere, and why does it not increase ? The amount of C02 in the atmosphere is about 4 parts by vol- ume in 10,000. This is quite constant, as the C02 generated in the various ways is absorbed by plants and also inorganic ma- terial. To what is the vitiation of the atmosphere in crowded rooms due? Partly to the carbonic dioxide exhaled by the persons in them and that generated by the burning of lights therein, also to the organic exhalations from the lungs. What is the smallest amount of space permissible for each occu- pant of dormitories ? The space for each individual should not be less than 400 cubic feet, but for the sick, and especially those suffering from offen- sive diseases, it should be at least two or three times as much. How does C02 act as a poison ? It acts similar to water in drowning persons by keeping the oxygen of the air from reaching the haemoglobin of the blood, and preventing the elimination of the C02 produced in the blood and tissues. How are persons overcome by C02 to be treated when in inac- cessible localities ? If they cannot be reached or removed from the place, by add- 94 ESSENTIALS OF MEDICAL CHEMISTRY. ing freshly burned charcoal, which absorbs 35.5 volumes of the CO.,, and by so doing sets up a current of air towards him, also by freshly slaked lime or forcing in currents of fresh air ; if re- moved therefrom, by artificial respiration, cold douche, fara- dism, friction, etc. What is carbon monoxide ? Carbon monoxide or carbonous oxide, also improperly termed carbonic oxide, is a compound of divalent carbon with oxygen, CO11, m. w. 28. A colorless, odorless, tasteless gas, little soluble in water, sp. gr. 0.969. How is it prepared, and how does it ordinarily result ? It is prepared either by passing C02 over heated charcoal C02 -f- C = 2CO, or by heating oxalic acid with strong sulphuric acid, the latter decomposing and withdrawing II20, and liber- ating COa and CO ; II.2C.i04 = H20 -f- CO,2 + CO. It results ordi- narily by incomplete combustion of coal, as noticeable in coal stoves after the draft has been shut off, also in burning charcoal in the charcoal basins without fanning. What are the chemical properties of Co? It does not support combustion, but is combustible, burning with a blue flame to C02, reduces many metallic oxides at red heat, and as an unsaturated compound unites with other elements directly. How does it act as a poison ? It acts as a direct poison, paralyzing the red corpuscles, and destroying the function of haemoglobin as an oxygen carrier, by uniting with it to form carbonic-oxide haemoglobin, which cannot again form oxyhaemoglobin. What is its effect when inhaled in small quantities ? It produces languor, debility, anaemia, and its accompanying symptoms ; as little as 0.5 per cent, will kill a bird. Why is coal gas poisonous, and why is water gas more so than the former? Because coal gas contains about 5 per cent. CO, and water gas about 27 to 30 per cent. CHEMISTRY. 95 How can CO be determined quantitatively? By agitating the gas or air to be examined in a eudiometer with an ammoniacal solution of cuprous chloride, which will absorb it and indicate the amount by the difference of volumes after opening it under water. How is carbon monoxide detected in the blood after death ? The blood has a bright-red color; when examined with the spectroscope it presents bands similar to oxyhaunoglobin ; the latter, however, can be converted to reduced haemoglobin by reducing agents, but the carbonic oxide haemoglobin remains unaltered when thus treated. How are cases of poisoning by CO to be treated ? Removing the gas present in the lungs by artificial respira- tion ; this is not curative however. Transfusion of blood would be indicated here, also inhalation of oxygen, but principally liberal and readily assimilated foods, stimulants, and iron. What are the compounds of carbon with sulphur ? Carbon disulphide CS2 and carbon oxysulphide COS. What is carbon disulphide ? A colorless, mobile liquid, of high refractive power, peculiar disagreeable odor, CS2, m. w. 76, sp. gr. 1.27, boiling at 46° C. ; it burns with blue flame to C02 and S02, dissolves iodine with violet color; also dissolves phosphorus, sulphur, caoutchouc, fats, and oils. What compound does carbon form w'th nitrogen ? Cyanogen gas, C2N2, m. w. 52 ; a colorless gas, of penetrating, pungent odor, similar to that of peach kernels ; sp. gr. 1.806 ; coercible, soluble in water, burning with purple-red flame to CO and N. What is C ,N, really, and in which form found in compounds ? CZN C2N2 is really dicyanogen of the graphical formula | CeN and is met with in compounds as the univalent radical cyanogen Cy or — CeN, which behaves chemically like the halogens, form- 93 ESSENTIALS OF MEDICAL CHEMISTRY. ing binary compounds with the metals, such as KCy, AgCy, and forms a binary acid with H, i. e., HCy, also ternary acids, such as cyanic acid 1ICNO, and sulphocyanic acid HCNS. What is hydrccyanic acid? Hydrogen cyanide, also termed Prussic acid, HOIS' or IlCy, a colorless, mobile liquid ; boiling at 27° C. ; of the specific odor of peach kernels. How is HCy formed, and how made? It forms by the action of the emulsion of bitter almonds on the amygdalin contained therein, in a similar manner also in cherry laurel leaves, peach kernels, wild cherry bark, etc. It is also found in the essential oil of bitter almonds. It can be made by decomposing a cyanide KCy or AgCy with a stronger acid, 2KCy + II2S04 - K,S04 -f 2HCv. State the strength of U. S. and cf Scheele’s HCy. The hydrocyanic acid of the U. S. Ph. contains 2 per cent, of HCy, Scheele’s acid 5 per cent. The Pharmacopoeial prepara- tion is unstable, and therefore of uncertain strength. What is the toxic effect of HCy ? Ilyd roeyanic acid in solution, in vapor form, or as soluble cya- nide, is very poisonous, death taking place, as a rule, within a short time, preceded by convulsions, unconsciousness, slow and labored respiration, cold extremities, dilated pupils ; generally the patient is dead before aid is rendered ; but if he survives one hour there is hope of recovery on account of the volatility of the poison. What is the treatment of poisoning by HCy ? Cold affusions, ammonia, galvanism, stimulants, atropine, chlorine developed from bleaching powder and vinegar. Smith’s antidote, composed of ferrous and ferric salts, in presence of alkaline carbonates forms non-poisonous Prussian blue. How is HCy detected after death ? 1. By the probable presence of its characteristic odor. 2. By placing the part to be examined, after acidulation, in a jar, and this in warm water, and then cover the jar with a glass plate CHEMISTRY. 97 moistened with AgN02; if HCy is present a white film of AgCy will form ; this is not soluble in cold HN03 or only sparingly in NH,IIO. 3. Proceed in the former manner, but moisten the glass plate with KOH, instead of AgNO.(, and touch with a ferric and ferrous salt, which, on addition of IIC1, gives rise to a deep blue color. 4. Moisten the glass plate as in the fore- going tests, but with ammonium sulphydrate, and then test with solution of ferric chloride, which, if HCy is present, gives rise to a red color, readily discharged on addition of a solution of mercuric chloride. This is due to ammonium sulphocyanide being formed, and saliva containing it gives the same reaction. Meconic acid also gives rise to a red color with ferric chloride, but it is not discharged on addition of HgCl2. What is the oxyacid of (CN)2, and what compound does it form with ammonium ? Cyanic acid IICNO, which forms ammonium cyanate NH4CNO with ammonium. Of what interest is ammonium cyanate ? Because it is isomeric with and convertible into carbamide or urea CON2II4. What is isomerism ? When two substances are composed of the same kind and number of atoms, but of different physical characters, owing to the different arrangement of their atoms in the molecule. State and explain the two kinds of isomerisms. Metamerism, when bodies of different physical character cor- respond in centesimal composition and molecular weight, and polymerism when they correspond in centesimal composition, but their molecular weights are different, the one being the mul- tiple of the other. Give the formula of sulphocyanic acid, name its salts, and which occur in the body. Sulphocyanic acid HCNS ; forms sulphocyanides ; potassium and sodium sulphocyanide are found in the saliva, and give red color with ferric chloride, which is discharged by mercuric chloride. 98 ESSENTIALS OF MEDICAL CHEMISTRY. Which are the principal metallocyanides and their use ? Potassium ferrocyanide, K4FeCy6, yellow prussiate of potas- sium, which gives blue precipitate of Prussian blue with ferric salts and potassium ferrieyanide, KfiFe2Cy12, red prussiate of potassium, which, with ferrous salts, gives a dark blue precipi- tate of Turnbull’s blue. Silicon. What is silicon ? An elementary solid, SiIV, a. w. 28. Which compound of silicon is most abundant ? Silicic oxide Si0.2, m. w. 60, is found abundantly in minerals, quartz, rocks, and sand ; it is found in all natural waters and in the cereals. Combined with water it forms acids which yield silicates. What silicates are of interest in medicine? The sodium or potassium silicates Na.2SiO:j,K2SiO;j, which are soluble in water, and are used for fixing surgical dressings under the name of liquid glass. What other silicates find common use ? The mixed silicates of sodium and calcium, or potassium and calcium, or lead and potassium, under the name of glass. What are the different varieties of glass, their composition, and use? Soda or soft glass, composed of sodium and calcium silicates, fuses readily, used for window and ordinary glass vessels. Pot- ash, Bohemian, also hard glass, composed of potassium and cal- cium silicates, not very fusible, are used for the manufacture of chemical glassware. Crystal or flint glass, composed of lead and potassium silicates, fuses more readily, refracts light, and acquires a clear lustre ; it is used for lenses aud optical purposes, etc. CHEMISTRY. 99 Metals of the Alkalies. Which are the metals belonging to this group and their common characteristics ? Potassium, sodium, lithium, rubidium, caesium, and am- monium. This latter though a compound is generally grouped with them. They are all soft, fusible, and volatile, have great affinity for oxygen, decompose water, readily forming basic oxides which with water yield caustic hydrates ; they form sol- uble carbonates and only one chloride. Potassium. What is potassium ? A waxy, bluish-white metallic element K1, a. w. 39, sp. gr. 0.865, melting at 62.5° C., distilling at red heat. What are its chemical properties ? It has a great affinity for O, tarnishes in the air, and if thrown on water it decomposes it; K-(-II/)=KOII-f II liberat- ing II which ignites and burns with a violet flame. It has to be kept immersed in a hydrocarbon on this account. Where and how is K formed ? Potassium exists in nature only in compounds, both in minerals as well as in plants, from the latter of which it is largely ob- tained by leaching out their ashes after combustion ; it is then termed potash or pearlash, which consists principally of K^CO^. How is K separated from K2C03 ? By reduction of the carbonate with charcoal and distilled over K2C03+2C=2K+3CO. When metallic potassium is thrown on water how is the water affected after the reaction, and why ? The water will become alkaline after reaction on account of the formation of potassium hydrate KOI!. 100 ESSENTIALS OF MEDICAL CHEMISTRY. What is potassium hydrate ? Potassium hydrate or hydroxide, also termed caustic potash KOII, m. w. 56.7, is a white crystalline mass which deliquesces readily, absorbing II20 and C02; it has a strong alkaline reaction, is readily soluble in alcohol and water, and, from being cast in moulds, comes usually to market in thin sticks. How is KOH prepared ? By decomposing the carbonate with calcium hydrate and evaporating the clear solution to dryness. K2COs+Ca(OH)2= CaC03+2K0H. What is the officinal solution of KOH ? An aqueous solution of potassium hydrate termed liquor potassse containing about 5 per cent. KOH, sp. gr. 1.036; 28 grams should require not less than 25 c.c. of the volumetric solution of oxalic acid for neutralization. How is the strength of alkaline solutions determined ? By alkalimetry with a volumetric solution of oxalic acid, q. v. How is the process of alkalimetry performed ? A certain amount of the alkaline solution to be tested, say 10 c.c., is placed in a beaker glass diluted, and to it are added a few drops of blue litmus solution as an indicator; then the volu- metric solution of oxalic acid is dropped into it until the change of color of the litmus to violet denotes the neutralization. The result is then computed either by stoichiometric proportion or by reference to already computed tables, or expressed simply in the quantity of oxalic acid solution used. What is the action of KOH on the tissues ? It dissolves and destroys them. What class of poisons does it belong to, and what others belong to this class ? The alkaline caustics, made up of potassium hydrate, sodium hydrate, and ammonium hydrate. State the symptoms produced by this class of poisons. Acrid taste, burning sensation in mouth and oesophagus, con- OHLMISTRY. 101 striction of fauces, inability to swallow, intense pain in stomach, abdominal tenderness, purging, prostration, mouth and tongue covered with white blisters and eschars. If the patient survives there may be sloughing followed by stricture of the oesophagus and a white waxy appearance from inanition. What are the antidotes for poisoning by the alkaline caustics ? Diluted vinegar, lemon juice, or other mild vegetable acids, also oils, fats, or milk. What are the tests for potassium hydrate? Alkaline reaction, absence of effervescence when neutralized with acids, violet color of non-luminous tiame when platinum covered with it is introduced. Neutralized with HC1, a yellow precipitate with platinum chloride ensues. Which are the potassium compounds with the halogens ? Potassium chloride KC1 crystallizes in vitreous cubes, sp. gr, 1.84, found in the blood. Potassium bromide KBr obtained together with potassium bromate, KBrO„ by the action of bro- mine on potassium hydrate, crystallizes in cubes, sp. gr. 2.24. Potassium iodide, KI, crystallizes in cubes, sp. gr. 2.9, dissolves in 0.7 parts of water. Potassium fluoride KF1 crystallizes in cubes, is very soluble in water, and etches glass. How are KBr and KI chemically distinguished? Their solutions when decomposed by Cl, give in the case of KBr, Br, recognized by giving a yellow compound with starch water, and in the case of KI, a blue starch iodide ; the iodine liberated in this latter test can also be shown by the violet color imparted when shaken with or with chloroform. What is potassium cyanide? A compound of K with Cy, KCy, a white fusible mass, de- liquescing in air, of the odor of prussic acid, is very poisonous like HCy only slower ; treatment for poisoning by it is as in HCy. Which is the officinal potassium sulphide ? The liver of sulphur or potassium pentasulphide K2S5. 102 ESSENTIALS OF MEDICAL CHEMISTRY. What is potassium hypochlorite ? A compound of K with HC10, which exists only in solution, known as Eau de Javelle, which has a chlorine odor, and is a powerful bleaching and disinfecting agent. What is potassium chlorate? A salt of chloric acid HC103, in which the H is replaced by K, formula KC103; crystallizes in shining tablets, not readily sol- uble in water. It has a saline, cooling taste, is astringent, and is used to make oxygen, q. v.; it is used internally, and also as a gargle, etc ; is poisonous in over doses, and after death is found in the kidneys ; it explodes violently when heated or rubbed up with oxidizable substances, and should not be prescribed with these in powder form. Which are the two sulphates of potassium ? Neutral potassium sulphate K2S04, crystallizes in rhombic prisms, of a bitter, saline taste, formerly employed in making Dover’s powder. Acid potassium sulphate KHS04, crystallizes in rhombic tablets, readily soluble in water. Describe the salt known as saltpetre, and its use. Potassium nitrate KN03, also termed nitre; the result of the decay of nitrogenous substances in presence of potassium car- bonate, this process being artificially employed for its production. It crystallizes in six-sided rhombic prisms, has a cooling taste, fuses at 3.38° C., and at higher heat gives off oxygen. It is principally used in the manufacture of gunpowder ; it is poison- ous in over doses. Antidote : emetics and raw eggs. What two chromates of potassium are there ? Potassium chromate, also termed neutral potassium chromate, K2Cr04, yellow rhombic crystals, used as an indicator in the de- termination of chlorides. Potassium dichromate K,Cr,0., also called acid or red potassium chromate, crystallizes in large red triclinic prisms. It is used with II.2S04 in battery fluid. It is an active poison. Antidote : magnesia and alkaline earths. What is potassium permanganate ? KMn04, crystallizing in dark-purple prisms, soluble in water CHEMISTRY. 103 with a beautiful purple color; a valuable oxidizing agent and disinfectant, oxidizing organic matter and forming brown man- ganese sesquioxide. Its solution in water is known as Coudy’s fluid. Which are the two carbonates of potassium ? The neutral potassium carbonate, salt of tartar, or pcarlash K,COs, a white granular deliquescent powder, readily soluble in water with alkaline reaction, and the hydropotassium carbonate or acid potassium carbonate, also termed potassium bicarbonate KIICO3, crystallizing in monochnie prisms, not so readily soluble in water as the normal salt. What is potassium citrate? The potassium salt of citric acid, abbreviated formula, K((T; officinal in the liquor potassii citratis, also the mistura potassii eitratis ; it is antifebrile, and renders the urine alkaline by being converted into carbonates. Potassium acetate, what is it? A potassium salt of acetic acid KC.,H:iO., or KA ; crystalline and very deliquescent ; it is diuretic and laxative. Which is the principal potassium cxalate? The acid potassium oxalate or binoxalate of potassium KIIC.,0, ; a mixture of this with the quadroxalate is known as salt of sorrel or salt of lemon, used for removing ink stains ; re- sembles Epsom salts in appearance, and often mistaken for it. It is poisonous, the same as oxalic acid, q. v. What is potassium tartrate, and what acid potassium tartrate? Potassium tartrate or soluble tartar results when two II of tartaric acid are replaced by K; 1^0,11,0,;; it is very soluble in water. Acid potassium tartrate or potassium bitartrate, also termed cream of tartar, the salt resulting when only one II of tartaric is replaced by K ; it crystallizes in rhombic prisms, only slightly soluble in water, and of acid reaction. From what is cream of tartar made ? From argols, the impure acid potassium tartrate deposited from the grapes in the casks during vinous fermentation. 104 ESSENTIALS OF MEDICAL CHEMISTRY. How are potassium compounds recognized ? They are mostly readily soluble in water. Tartaric acid will give with concentrated solutions a white precipitate of acid po- tassium tartrate; introduced into a non-luminous flame, they give rise to a violet coloration. The spectrum exhibits one red and one violet line. Sodium. What is sodium ? A silver-white, soft, elementary metal NaT, a. w. 5% sp. gr. 0.98; fusing at 97° C., and distilling over at red heat. It oxi- dizes and tarnishes readily when exposed, decomposes water disengaging H, and has to be preserved under a hydrocarbon. It burns with a yellow flame. How is sodium prepared ? Like potassium, by heating sodium carbonate and charcoal to a white heat in an iron retort, when it distils over. Where and how does sodium occur ? It is abundant as chloride in rock salt, also in sea-water and saline springs; also in deposits, as sodium nitrate and borate. What is sodium hydrate ? Sodium hydrate or hydroxide, also termed caustic soda, NaOH, is a white, crystalline substance, usually found in the market in cylindrical sticks presenting radiating crystalline fractured surfaces, attracts moisture, and on exposure changing on the surface to sodium carbonates. Its solution in water is known as soda lye, the officinal solution as liquor sodse. What are the properties of liquor sodse, and how is it prepared ? It is an aqueous 5 per cent, solution of NaOH, sp. gr. 1.059, 20 grams should not require less than 25 c.c. of volumetric solution of oxalic acid for neutralization ; it belongs to the caust ic alkaline poisons, producing the same symptoms as IvOH and requiring the same antidote. It is prepared similarly as KOII from Na2C03 and Ca(OH)2; Na2C03 + Ca(OII)2 = CaC03 + 2 NaOH. 105 CHEMISTRY. What is the respective physiological effect of potassium, and what of sodium compounds ? Potassium compounds are heart and muscle poisons, while those of sodium are inert. What is the chlorine compound of sodium? (Sodium chloride, common or table salt, NaCl, crystallizing in transparent cubes, sp. gr. 2.13, soluble in about 3 parts of water. What is the function of NaCl in the animal economy ? It is found in all tissues and liquids of the body, especially in the blood. It is ingested with the food and principally elimi- nated by the kidneys. In the tissues it tends to promote cell nutrition by conducting the osmotic process; it appears in all excretions but dhiefly in the urine. In what quantities is NaCl, or chlorides represented by it, eliminated in £4 hours ? The total chlorides of the urine eliminated in 24 hours, con- sisting principally of sodium and potassium chlorides, average about 12-16 grams. What influences the amount of chlorides present in the urine ? The amount ingested, also the condition of health ; thus in febrile diseases they are diminished, especially when these are due to inflammatory exudations ; e. g., in pneumonia, they may be almost or totally absent and reappear with a limitation of the inflammatory process. How is the presence of chlorides in the urine demonstrated ? By adding first a few drops of IINO,, to prevent the precipita- tion of the phosphates, and then adding a solution of silver nitrate, when a more or less dense precipitate of silver chloride will indicate approximately the amount of chlorides present: N aCl+AgN 0:i=N aN O, -)- AgCl. How are the chlorides in the urine volumetrically determined ? With a solution of silver nitrate standardized to precipitate accurately 0.01 NaCl for each c.c. (29.06 AgNOs to 1 liter 11,0.) 10G ESSENTIALS OF MEDICAL CHEMISTRY. Describe the process for determining volumetrically the amount of chlorides in urine. Dilute 10 c.c. urine with 50 c.c. water in a porcelain dish or beaker, add a few drops of neutral potassium chromate solution to give it a distinctly lemon-yellow color. Allow the silver nitrate solution to gradually flow into it, while stirring, until the urine turns permanently orange-red. Each c.c. of the silver solution used indicates 0.01 NaCl present in the 10 c.c. urine, or ten times the total number of c.c. the percentage of chlorides expressed in NaCl, subtracting one c.c AgNO., solution for supersaturation. If the urine is highly colored or putrid or albuminous, what should first be done ? The organic matter should be oxidized with potassium per- manganate solution gradually added while boiling until a faint pink hue remains ; the resulting manganese sesquioxide is then filtered off, the quantity brought up to the original volume with distilled water, and proceeded with as above. What is sodium bromide ? A binary compound of sodium and bromine NaBr, soluble in 1.13 parts of water at 20° C., and representing 77.07 per cent. Br. What binary compound does Na form with I? Sodium iodide Hal, dissolves in 56 parts of water at 20° C., and represents 84.6 percent, iodine. What is sodium hypochlorite, and in what preparation is it contained ? Sodium hypochlorite, NaCIO, is contained in the liquor sodce chloratae or Labarraque’s solution, prepared by decomposing a saturated solution of chlorinated lime with a solution of sodium carbonate. It is a powerful bleaching and disinfecting agent. Give the formulae of the chlorate, bromate, and iodate of sodium. Sodium chlorate NaC103, sodium bromate NaBr03, sodium iodate NaI03. Which is the principal sulphate of sodium ? The neutral sodium sulphate I7a3S04 known as Glauber’s salt, 107 CHEMISTRY. crystallizing in large efflorescent prisms, which melt in their water of crystallization when heated. How do the sulphates get into the blood, and how are they eliminated ? The sulphates of potassium and of sodium are in part directly derived from the foods, and also together with organic sulphur compounds from the oxidation of the albuminoids of the body. They are eliminated by the urine in quantities of about 3 to 4 grams in 24 hours. How may the sulphates of the urine be demonstrated and ap- proximated ? By acidulating the urine with a few drops of IIC1 and then adding a solution of barium chloride which causes a white pre- cipitate; this may be compared for approximation with that from a known normal specimen of urine. How are the sulphates determined volumetrically ? By acidulating 100 c.c. urine with IICl and boiling it. Into this drop gradually from a burette the standard solution of barium chloride (30.5 BaCl., in 1000 11,0), until no further pre- cipitate ensues, testing this frequently to attain accurate results. Each c.c. of the Bad, solution used corresponds to 0.01 grm. SO.,, the total number of c.c. BaCl, used gives at once the per- centage. What are sodium sulphife and hyposulphite? Sodium sulphite Ha,SO.,, the salt resulting when the H in H,SOs is replaced by Ha. Sodium hyposulphite Ha,S,03 is a reducing agent and a disinfectant. Which are the principal sodium phosphates ? The disodium phosphate or neutral sodium phosphate Ha, IIP04, sodii phosphas U. S., slightly alkaline; and the mono- sodium phosphate or acid sodium phosphate HaII,P04 of acid reaction. When Na,HP0, is heated what forms? It loses water and forms sodium pyrophosphate Ha4P,07. 108 ESSENTIALS OF MEDICAL CHEMISTRY. Where is the NaHPO, found in the body and where the NaH2 PO,? The Na2IIP04 is found in all the tissues and liquids of the body but is converted into tbe NaII2P04 by the NaIIC03 of the blood and eliminated as such in the urine, to which the latter owes its normal acid reaction. Na2IIP04+NaHC03==NaH2P04-p Na2C03. Which are the two principal carbonates of sodium ? Sodium carbonate, sal soda, washing soda, Na2C03, and hydro- sodium carbonate, acid sodium carbonate, also sodium bicarbon- ate, NaHCO,. What is sodium carbonate? Where and how obtained? Sodium carbonate is found free in nature, but mostly manu- factured on a large scale from sodium chloride. It is a salt crystallizing with 10 Aq, in large efflorescent crystals, has a strong alkaline reaction and yields C02 when treated with acids. What is sodium bicarbonate ? A salt manufactured by treating Na2C03 with C02 (Na2C03-+- C02-|-H20=2NaHC03), of feeble alkaline reaction, giving up C02 on heating and boiling forming Na2C03; it crystallizes without water entering its molecule. What officinal preparations does NaHC0:! enter? The soda powders (pulveres effervescentes) and the Seidlitz powders (pulveres effervescentes aperientes) ; the former con- taining NallCOj and tartaric acid in different papers, the latter NaHC03 with Itochelle salt and tartaric acid, also in two sepa- rate papers. How is NaHCO, used in baking? To aerate, i. e., raise the bread, hence its name sal sera tus or baking powder. It should be mixed for this purpose with either cream of tartar or tartaric acid sufficient to change it into a neutral tartrate, while the C02 given off will render the bread light and spongy. What is Rochelle salt? Sodium potassium tartrate NaKT. 4- 4Aq. A double salt of CHEMISTRY. 109 tartaric acid, in which one II is replaced by K and the other by Na. It is prepared by neutralizing cream of tartar with sodium carbonate; it crystallizes in large transparent prisms, and is readily soluble in water. How are sodium compounds recognized ? They are almost all readily soluble in water ; inserted into a non-luminous flame they give rise to a yellow coloration, and, viewed through the spectroscope, they exhibit a yellow line. What is lithium ? An elementary metal Li, a. w. 7, sp. gr. 0.59; the lightest of all metals known ; found in compounds in various minerals and in the waters of some mineral springs. What is lithium carbonate ? Lithium carbonate Li2C03; a valuable antacid, rendering the urine alkaline, and forming soluble lithium urate with uric acid. It is a white, pulverulent substance, very little soluble in plain water, hut considerably more so in carbonic acid water. What is lithium bromide, and what its advantages over other bromides? Lithium bromide LiBr is a crystalline substance, very deli- quescent, containing more bromine than any other bromide (91.95 per cent.). What are the characteristic flame reactions of Li compounds ? They produce, when inserted into non-luminous flames, a bright-red coloration, which, when viewed through a spectro- scope, causes an intense red line in the spectrum. Lithium. Ammonium. Why should ammonium, NH„ be considered with the metals of the alkalies? Because it shows in its chemical action much similarity to them, forming salts like them, and can be converted into an amalgam with mercury, NII4IIg. 110 ESSENTIALS OF MEDICAL CHEMISTRY. What is ammonium hydrate? NHtOH, formed by passing gaseous ammonia NH, into water, NH3 + H„0 = NH4OH ; a clear liquid, of strong amtnoniacal odor, lighter than water, of a strong alkaline reaction, which, on heating, is decomposed into NII3 and H20. What is aqua ammoniae, and what aqua ammoniae fortior U. S.? Aqua ammoniae is an aqueous solution of Nil,,, sp. gr. 0.950, containing 10 per cent, by weight of the gas. Aqua ammoniae fortior is the same, but has a sp. gr. 0.900, and contains 28 per cent, by weight of the gas. To what class of poisons does NH40H belong? To the caustic alkalies, producing the symptoms of these with greater respiratory disturbances, and requiring the antidotes already mentioned for this class (see Potassium hydrate). Which are the principal halogen compounds of NH,? Ammonium chloride NH4C1, ammonium bromide NII,Br, am- monium iodide NH4I. How is NH.Cl prepared, and what are its properties? Muriate of ammonia or sal ammoniac NH4C1 is prepared by neutralizing NII4OfI with IIC1; NII.OII + HC1 = NII4C1 + 11,0 ; crystallizes in small feather-like forms, of a sharp, salty taste ; dissolves readily in water, and sublimes without melting ; heated with KOII, NaOII or Ca(OH)2, it gives off Nil.,. What is ammonium hydrcsulphide and its use ? Ammonium sulphydrate, NH4HS, is a compound produced by saturating NH4OII with II.2S ; it is at first colorless, but becomes yellow. It is principally employed as a precipitant in the labo- ratory for analytical purposes. What is ammonium sulphate ? (NTI4)2S04, obtained by saturating NII4OH with II2S04; a crys- talline salt, readily soluble in water. What is ammonium nitrate, and its use ? NII4NO.„ a salt produced by neutralizing NTI4OII with IINOa, and crystallizing from its solutions in long six-sided prisms. It CHEMISTRY. 111 is very soluble in water, and fuses at 150° C., decomposing at 210° into nitrous oxide N20 and water; this is utilized for the production of nitrous oxide for anaesthesia. Where is ammonium nitrite found, and how formed ? It is found in the air after thunder-storms and in rain-water, resulting from the action of the electric spark on moist air. Which are the carbonates of ammonium ? Neutral ammonium carbonate (NH4)2C03 decomposes readily into NHj and acid ammonium carbonate NH41IC03. The am- monii carbonas U. S., or so-called ammonium sesquicarbonate, also sal volatile, is a mixture of the acid ammonium carbonate with ammonium carbamate (NH4HC03 + NH4NH2C02). How can ammonium compounds be recognized ? They are colorless, volatile, and give off NH3 when treated with bases. This may be recognized with moist litmus paper, which turns blue. With platinum chloride they give a yellow, crystalline precipitate. Metals of the Alkaline Earths. Which are the metals composing this group ? Calcium, strontium, barium. What are the characteristics of the metals of this group ? They are divalent, form basic hydrates, and insoluble carbon* ates, phosphates, and sulphates. Calcium What is calcium ? A light-yellowisli metal Ca, a. w. 39.9, sp. gr. 1.5778, decom- poses water, and burns with a bright light. It is abundant throughout nature in its compounds, principally as carbonate. What is the principal calcium oxide, and how prepared ? Calcium oxide, also termed lime or quicklime, calx U. S. CaO is prepared from the native calcium carbonate CaC03 (lime- 112 ESSENTIALS OF MEDICAL CHEMISTRY. stone or marble), by heating it in kilns for that purpose. CaC03 = CaO -f C02. From the air it attracts C02 and again forms CaC03. Slaked lime, what is it chemically, and how obtained ? Slaked lime or calcium hydrate Ca(OH)2 is a white amorphous powder, forming a milky paste with water (milk of lime), and dissolves in cold water, about 1 part in 760 ; this is termed lime- water, liquor calcis U. S., and prepared by the action of water on CaO ; CaO + H20 = Ca(OH)2. What is syrupus calcis ? A solution of Ca(OH)2 in sugar and water. The addition of sugar makes the Ca(OII)2 very much more soluble, 1 fluidounce containing about 8 grains. If lime is taken in substance, what is the effect, and what the antidotes ? It acts as a caustic poison. Antidotes: diluted acids and oils. What is calcium fluoride ? Fluorite or fluor-spar CaFl2, used for obtaining hydrofluoric acid HF1. What are the compounds of Ca with Cl, Br, and I? Calcium chloride CaCl2 calcium bromide CaBr2, calcium iodide Cal,. How is calcium chloride prepared and how used ? It is prepared by the action of IICl on CaC03; CaC03 + 2IICl =CaCl2+H2C03. It is a crystalline deliquescent salt, which, when heated, loses its water of crystallization and appears in a fused state ; it is used for freezing mixtures, also for desiccating gases. What is chlorinated lime ? Bleaching powder or calx clilorata is probably a mixture of calcium hypochlorite Ca(C10)2 and calcium chloride CaCl2 or CaClClO ; it is prepared by passing chlorine over slaked lime : 2Ca(OH)s+2ClJ=Ca(OCl)a+CaClJ+2IIaO, CHEMISTRY. 113 and is used principally as a bleaching and disinfecting agent, de- pending on the liberation of Cl by lIvCO. of the air or by other acids admixed with it. Calx sulphurata U. S., what is it? A mixture of calcium sulphide CaS and calcium sulphate CaS04, prepared by heating together lime and precipitated sulphur. What is calcium sulphate, and in what form is it generally used? Calcium sulphate in its crystalline form is known as gypsum CaSO,-p2Aq, and when dehydrated by calcination is known as plaster of Paris, used for fixed surgical dressings, as on mixing with water it again assumes its hydrated crystalline state. What compounds does Ca form with phosphoric acid ? The acid calcium phosphate or monocalcium phosphate, also termed superphosphate of lime, Ca(Il,P04).,; the di-calcium phosphate Ca2(HP04)2-l-2H20, and the tricalcium phosphate or neutral calcium phosphate, also termed bone phosphate and precipitated phosphate of calcium Ca.,(P04)2. Which of the three calcium phosphates is principally found in the body, and what part thereof? All three are found in the body, but principally the neutral salt, which is contained in a large amount in the bones and the teeth; it is sometimes found in the urine, the acid salt being always present therein and forming there along with the mag- nesium phosphate the so-called earthy phosphates. What is the total elimination of phosphoric acid by the urine in 24 hours, and what part of the phosphates so elimi- nated are phosphates of the alkalies, and how much earthy phosphates ? The total elimination of phosphoric acid in the form of phos- phates is about 2-3 grams in 24 hours, two-thirds of which are alkaline and one-third earthy phosphates. How can the earthy phosphates of the urine be separated? By rendering the urine alkaline with KOII or NaOIl, when, 114 ESSENTIALS OF MEDICAL CHEMISTRY. on heating, the earthy phosphates will separate out in flakes, and then can be removed by filtration. After separation of the earthy phosphates how can the a’kaline phosphates be precipitated ? By adding to the filtrate one-third of its volume of magnesia mixture the alkaline phosphates will be precipitated. How can the total amount of phosphoric acid in urine be readily approximated ? By Teissier’s method; in a graduated cylindrical vessel add 50 c.c. urine and 15 c.c. magnesia mixture, shake together and let stand for 24 hours, each c.c. of the deposit will represent ap- proximately 0.30 grams P205 per liter or 0.03 per cent, thereof. How is the total amount of phosphoric acid in urine determined by the volumetric process ? Take 50 c.c. urine in a suitable vessel, add 15 c.c. acidulated solution of sodium acetate and heat to the boiling point; then drop into the mixture from a burette, drop by drop, a standard- ized solution of uranium acetate (1 c.c. to represent 0.005 P205). Test frequently by dropping some of the heated mixture into a solution of potassium ferroeyanide ; when a chocolate color pre- cipitate begins to appear the process is finished. For each c.c. of the uranium acetate solution used count 0.005 grams P2t)5 in the 50 c.c. urine, or twice as much to get the percentage. How does calcium carbonate occur in nature ? CaC03 is abundant and in vast deposits known as chalk, limestone, and marble \ it is also found crystalline as calc-spar, Iceland spar, and arragonite ; the shells of Crustacea, of birds’ eggs, corals, and the bones and teeth of animals contain it. What are the officinal forms of CaC03 ? Precipitated chalk, calcii carbonas prsecipitatus U. S., pre- pared by precipitating a solution of CaCl2 with Na2COH, and prepared chalk, creta prseparata U. S., a native friable calcium carbonate freed from most impurities by elutriation. What are the properties of CaCOj ? It is almost insoluble in pure water, but soluble in water con- 115 CHEMISTRY. taining 11 ,CO ,, forming probably calcium hydrocarbonate or acid carbonate, also called bicarbonate of calcium. As many waters, streams, and springs are strongly impregnated with 11,,00., they hold CaC03 in solution and deposit it on evapora- tion, as illustrated by the formation of stalactites. By which analytical reactions are calcium compounds recog- nized ? Solutions of calcium salts are precipitated by alkaline carbon- ates and phosphates ; ammonium oxalate gives a white pre- cipitate with them, insoluble in weaker acids, hut soluble in strong HC1 or UNO.,. With sodium tungstate they give dense white precipitates. Calcium salts color a non-luminous flame red. Barium. In which form dees barium occur in nature, and what are its symbol and a. w. ? Barium is found exclusively as a native sulphate, which, on account of its great weight, is also called heavy spar and barytes ; the native carbonate is termed witherite. The symbol of barium is Ba; a. w. 137 ; sp. gr. 3.6. What are the oxides and what is the hydrate of barium? There are two, barium oxide, also called baryta BaO, and barium peroxide Ba02, used in making hydrogen peroxide. When barium oxide is dissolved in water it forms barium hy- drate or hydroxide Ba(OIf)2, the solution being known as baryta water, which is strongly alkaline, and is rendered turbid by C02, insoluble BaCO;i being formed. What are the compounds of Ba with Cl and with HN03, and their use ? Barium forms a soluble crystallizable barium chloride, BaCl.„ with Cl, with UNO., it forms a soluble crystallizable barium nitrate Ba(N03)2 ; both of these salts are used for the detection and determination of sulphuric acid and soluble sulphates. What is the action of the soluble barium salts on the human economy? They are actively poisonous. Antidotes : soluble sulphates. 116 ESSENTIALS OF MEDICAL CHEMISTRY. How are the barium compounds recognized ? Their solutions give white precipitates with alkaline carbon- ates, also heavy white precipitates with II2S04 or soluble sul- phates, insoluble in acids, white precipitates with alkaline phosphates soluble in I1.N03; they color a non-luminous flame green. Magnesium Group. Which are the principal metals of interest in this group, and what are their common characteristics ? Magnesium, Mg, Zinc, Zn, Cadmium, Cd. They are all dyads forming but one oxide and one sulphide. Their oxides and hydroxides are almost all insoluble in water; they form soluble sulphates and insoluble carbonates and phosphates. Magnesium. What is magnesium ? A bright silver-white metal, Mg, a. w. 24, sp. gr. 1.75, burns when ignited with intense white light to magnesium oxide, MgO, dissolves readily in dilute acids forming salts, and is not attacked by alkalies. When and how does magnesium occur in nature? Its compounds abound in nature as carbonate, as silicate in talcum, soapstone, asbestos, and meerschaum, as soluble salts in most natural waters, and largely so in sea-water and some mineral springs ; they are also present in the economy into which they enter by the foods and water, and are eliminated by the urine as phosphate. What is magnesium oxide ? Magnesia or calcined magnesia MgO, obtained by calcining the hydrate or carbonate ; a white, voluminous, amorphous pow- der, very insoluble in water; two varieties are used in medi- cine, of which the former is known as magnesia or magnesia levis, while the heavier article is known as magnesia ponderosa. CHEMISTRY. 117 What is magnesium hydrate? Magnesium hydrate or hydroxide Mg(OII)2 is the precipitate resulting when a solution of a magnesium salt is decomposed by the hydrate of potassium or sodium ; in suspension with water it is known as milk of magnesia. What is magnesium chloride? A very deliquescent salt MgCl2, present in many mineral springs, and in some impure grades of table salt. What is magnesium sulphate? Magnesium sulphate, Epsom salt MgS04 7Aq, found in sea- water and in a number of mineral springs. It crystallizes in four-sided rhombic prisms, is readily soluble in water, has a bitter, saline taste, and finds much use as an aperient. Which are the principal phosphates of magnesium ? The tri-magnesium phosphate Mg.j(Po4).i in bones, the mono- magnesium phosphate MgHPo(+7Aq present in the urine; when it meets ammonium compounds, it forms the ammonium-magne- sium phosphate MgNII4P04 -+- 6Aq, also termed triple-phos- phate. MgIIP04 + NH4HO - MgNH4P04 + H,0. What is the cause of the formation of triple-phosphate in the urine, and what is its significance ? When urine is decomposed by putrefactive change ammonium carbonate is formed, CON,H4 + H.,0 = (NH4).,CO;4; this with magnesium phosphate yields ammonium-magnesium phosphate, which separates out in microscopic prismatic crystals resembling coffin lids. If these occur persistently, the liability to forma- tion of fusible or triple-phosphate calculi arises. Which are the principal carbonates of magnesium ? Neutral magnesium carbonate MgC03, which occurs in nature as magnesite. The inagnesii carbonas of the Pharmacopoeia is a mixture of magnesium carbonate with magnesium hydrate (MgCO:,),Mg(OHh+ 5H..O ; a white voluminous powder, usually ollered in the market as light-white cubes. This, when suspended 2MgHP04 + (N H4),CO, == H20O3 2MgNH4PQ4, 118 ESSENTIALS OF MEDICAL CHEMISTRY. in water and carbon dioxide, is passed through it, dissolves and forms what is known as liquor magnesii carbonatis or fluid mag- nesia. How are magnesium compounds recognized ? The alkaline hydrates precipitate from their solutions magne- sium hydrate, the carbonates basic magnesium carbonate; the precipitates are insoluble in water, but soluble in solutions of ammonium salts from which di-sodium phosphate precipitates ammonium-magnesium phosphate. What is zinc ? A bluish-white metal, Zn, a. w. 65, of crystalline fracture, sp. gr. 7-7.2; fuses at 412° C., and distils at about 1000° C. It is soluble in dilute with liberation of H, also in KOII or NaOII on boiling, when it yields II as with acids. What is zinc hydrate ? A white amorphous powder Zn(OH)2, precipitated by the de- composition of a zinc salt solution with an alkaline hydrate, in an excess of which it is freely soluble. What is zinc oxide? A white, tasteless powder, ZnO, insoluble in water, but freely soluble in acids, with which it forms salts; it turns yellow on heating, and white again on cooling. It is largely used in the arts for paint, as it will not darken on exposure to HaS like the lead pigment; it is also employed in medicine, both internally as well as externally, in the unguentum zinci oxidi. What is the chlorine compound of zinc ? Zinc chloride ZnCla, a white deliquescent fusible substance ; it is a painful caustic; in solution, containing 50 percent., it is known as liquor zinci ehloridi; it is used as a flux for solder, also as a disinfectant (Burnett’s disinfecting fluid) ; diluted it serves as a soft injection for the preservation of dead bodies. What is the toxic action of ZnCl,, and its antidote? It coagulates albumen, hence its corrosive action, and again Zinc. 119 CHEMISTRY. by absorption it manifests its specific action on the nerve centres, paralyzing motion, and causing tremor and coma. Antidotes : milk, eggs, and vegetable astringents. What sulphide do neutral solutions of zinc salts yield with H2S? A white zinc sulphide ZnS. What is zinc sulphate ? White vitriol ZnS04, crystallizing with 7Aq in rhombic crys- tals, resembling those of magnesium sulphate ; it forms insoluble compounds with albumen and milk ; it is a rapid, non-depress- ing emetic in doses of gr. xx-xxx. How may the compounds of zinc be recognized ? Their solutions give a white precipitate with alkaline hydrates, soluble in excess; K2C03 and Na2C03 white precipitate, insoluble in excess ; (NII4)2C03 white precipitate soluble in excess; HJS white precipitate from neutral solutions; ammonium sulphy- drate white precipitate, insoluble in excess of it, as well as in KOH, or NaOH, or NII4Oil; potassium ferrocyanide white precipitate, insoluble in IIC1. Lead Group. Which are the metals of this group ? Lead and thallium. Lead. What is lead? A bluish-white heavy metal, Pb, a. w. 207, soft and ductile, of bright lustre on freshly-cut surface, becoming tarnished after exposure ; sp. gr. 11.37; fuses at 325° C. ; forms alloys with other metals ; among these is type-metal, composed of lead and antimony, and soft solder of lead and tin. What is the principal source of lead ? Galena, a native lead sulphide, from which it is separated by roasting. 1*20 ESSENTIALS OF MEDICAL CHEMISTRY. V/hat is the action of water on metallic lead ? Pure water does not act on lead, but by the action of air and water, alternately, it becomes coated with lead hydrate Pb(OII)2, which is somewhat soluble in water; thus new lead pipes may give rise to the contamination of water. If the water contains C02 and salts, the lead becomes coated with insoluble carbonate and sulphate, and old pipes therefore give greater immunity from contamination ; however, by an excess of C02, the carbon- ate may be rendered slightly soluble. The presence of nitrates and nitrites in water conducted through lead pipes also tends to produce lead contamination in water. V/hat is lead hydrate ? Pb(OH)2; a white precipitate thrown out from solutions of lead salts by alkaline hydrates ; it renders water alkaline, and forms lead carbonate with COr Which are the principal oxides of lead ? Lead monoxide, PhO or litharge, lead peroxide or dioxide Pb02, plumboso-pluinbic oxide Pb,04 or minium. What is lead monoxide ? PbO, litharge, is the officinal plumbi oxidum, produced by heating lead in the air, is a reddish-yellow substance, of rhom- bic scales, or when obtained as yellow amorphous powder it is known as massicot. It has strong basic properties, saponifies fats, producing with olive oil the emplastrum plumbi U. S., melts at red heat, and unites with silicic anhydride to form lead glass ; it is employed thus to make the glaze on pottery ; it is also used as a dryer for paints ; it dissolves in water as hydrate, rendering it alkaline, and absorbs then C02; it also dissolves in hot solutions of KOII and NaOH, from which it crystallizes on cooling. What is lead peroxide ? Lead peroxide or dioxide, Pb02; a brown amorphous powder remaining when minium is treated with IINO:i. It has acid pro- perties uniting when warmed with KOII to form potassic plum- bate, K2PbOj -f- 3Aq. 121 CHEMISTRY. What is minium ? Red lead or minium is a bright red powder Pb30«, a compound of lead oxide with lead peroxide It is obtained by heating litharge to 300-400° C. in the air ; it is used as a pig- ment for red paint. What is lead chloride ? PbCl2, the white precipitate resulting by adding HC1 or a soluble chloride to solutions of lead salts. It is very little soluble in cold water, soluble in 30 parts of hot water, from which it crystallizes on cooling. What is lead iodide ? Pbl2, the yellow precipitate resulting from solutions of lead salts when treated with potassium iodide ; little soluble in cold but more freely soluble in boiling water, from which it crystallizes on cooling in beautiful six-sided [dates discernible under the micro- scope ; it is readily soluble in KOH. When solutions of lead salts are treated with H,S what results ? Lead sulphide PbS, a black amorphous powder, insoluble in dilute acids. In nature PbS occurs in cubic crystals of a metallic lustre, and is commonly known as galena. If sulphuric acid or soluble sulphates are added to solutions of lead salts what results ? Lead sulphate PbS04, a white powder almost insoluble in water. What is lead nitrate ? Pb(N03)2, a crystalline salt resulting when lead is treated with UNO.,; it dissolves in 8 parts of water, and as such forms a dis- infecting fluid called Ledoyen’s solution. When to a solution of lead salt potassium chromate is added what is formed? Lead chromate, chrome yellow, PbCrO,, a bright yellow amor- phous powder, insoluble in weaker acids but readily soluble in KOH. It is used largely in the arts as a pigment, and has been used with fatal effect to give buns and cakes the yellow color of eggs. 122 ESSENTIALS OF MEDICAL CHEMISTRY. Which is the principal lead salt used in medicine ? Lead acetate or sugar of lead Pb(C2H302)2+3 Aq, also termed saccliarum saturni, crystallizing in large, colorless prisms, of sweetish taste, acetous odor, acid reaction, and efflorescent on exposure ; with water containing CO., it makes turbid solutions, lead carbonate being precipitated. For what purposes is lead acetate usually employed ? In medicine as a sedative and astringent; it is generally found as an ingredient in the different hair-color restorers, and while not very actively poisonous itself it may become so if its use in such a manner is persistently continued. When lead acetate in solution is boiled with lead oxide, PbO, what results ? The PbO is dissolved and a solution of lead subacetate or basic lead acetate is formed, which is known as the liquor plumbi subacetatis U. S., also termed Goulard’s extract ; when diluted it is known as the liquor plumbi subacetatis dilutus or lead water. What is neutral lead carbonate ? Lead carbonate PbC03 is a white amorphous powder, different commercial forms of which are known as white lead, flake white, cremnitz white, etc., which are basic varieties ; such is also the plumbi carbonas U. S. (PbC03):!Pb(0II).i. For what purpose is the lead carbonate employed ? Principally as pigment and base for oil paints, for making plumber’s joints, in medicine in ointment form, for glaze of paper, and frequently as a most objectionable cosmetic. It is the most poisonous of the lead compounds. What are the symptoms of acute lead poisoning ? Metallic taste, thirst, colic, constipation, cramps, urinary sup- pression, convulsions, but the mind is preserved to the last. Is the prognosis in acute lead poisoning favorable, and what is the treatment for it ? Prognosis in such cases is generally favorable ; treatment should consist of emetics or stomach-pump followed by either CHEMISTRY. 123 magnesium or sodium sulphate and sulphuric acid lemonade to produce insoluble lead sulphate together with morphine for pain. From what sources may chronic plumbism arise ? From drinking water or beer conducted through new leaden pipes, inhalation of, or absorption by the skin of white lead or paints, from snuff or chewing tobacco wrapped in lead, from lead-glazed pottery, from contact with lead or lead compounds as in plumbers, painters, lead workers, miners, type founders, also from cosmetics and hair restorers containing lead, and even from hat linings or biting off'silk weighted with lead. What are the symptoms of chronic plumbism ? Indigestion, colic and constipation, cachexia, ptyalistn, weak- ness of muscles of forearm, lead palsy, wrist drop, paralysis of extensor muscles with atrophy of extensor and interosseous muscles ; blue lines arising from deposit of PbS on the gums due to the presence of II,S in the breath and decaying food ; arthralgia, encephalopathy, spasms, mania, melancholia, con- vulsions, coma. What is the treatment of chronic plumbism ? To clear out the alimentary tract with MgS04 or Na2S04, also potassium iodide, tincture of iron, and galvanism. How can lead compounds be recognized ? They give from acid solutions a black precipitate with II.J3, insoluble in acids, also with NII4HS insoluble in excess. With sulphuric acid or soluble sulphates a white precipitate ; with potassium iodide a yellow precipitate, also with potassium chromate. How is urine or other liquids, suspected to contain lead, to be tested ? Concentrate to dryness and incinerate ; dissolve residue in UNO., and evaporate solution to dryness over a water bath, dis- solve in distilled water and test with H2S. The sulphide, if sufficient, may then be reduced by the blow'-pipe to a malleable particle of lead, or it may be dissolved in IIN03, the acid evapo- 124 ESSENTIALS OF MEDICAL CHEMISTRY. rated and residue dissolved in distilled water to be tested with KI, when the lead iodide, after heating, will be seen under the microscope as six-sided plates. Copper Group. Of what metals does this group consist ? Copper, mercury, and silver. What is copper? A reddish-brown metal Cu, a. w. G3.2, soft and ductile, sp. gr. 8.9, unaltered in dry air, with moisture it is coated with green copper carbonate; on heating it oxidizes to black cupric oxide. Dilute HC1 or II2S04 does not act on it, but the stronger acids dissolve it to form salts. Which are the principal alloys cf copper ? Brass =Cu-|-Zn ; bronze Sn or Pb or Zn-f-Cu ; bell metal Sn-|-Cu ; German silver Cu-j-Zn-J-Ni. What two classes of compounds does copper form ? Cupric and cuprous ; it is divalent in the cupric and mono- valent in its “ ous” compounds ; the molecules of the latter, however, are to be regarded as double formulas. Copper. Cu Cu—Cl n /0=Cu,0 ; | =Cu.,CL ; “ ous” compounds. ' Cu—Cl Thus Cu=0,Cu=Cl,,,Cu=(0U),,Cu=S0+; “ic” compounds. What is cupric hydrate, and how derived? A greenish-blue precipitate resulting when a solution of a copper salt is treated with sodium or potassium hydrate. Cu (OII)2. It readily changes into black cupric oxide when heated. Cu(OH).2=CuO-f II20. What is cupric oxide ? A black amorphous powder CuO, forming when Cu(OH)4 is heated as above, also by oxidation of copper turnings in the CHEMISTRY . 125 air. By heating it reduces carbon compounds forming carbon dioxide and water of them. It dissolves in the alkaline hy- drates with a dark blue color, directly with NH4OH, and in the presence of organic substances with IvOH or NaOH. In the presence of glucose it is reduced at the boiling point to Cu20. What is cuprous oxide? A bright and crystalline powder Cu.,0, forming when a solu- tion of CuO in NaOII or KOII is boiled in the presence of grape sugar. Which are two chlorides of copper ? Cupric chloride CuCl2 and cuprous chloride Cu2Cl2. The latter dissolved in NII.IIO has the property of absorbing carbon mon- oxide, and is used for the analysis of that gas. What precipitate does H.S yield with copper solutions ? A brownish-black precipitate of copper sulphide CuS. Describe the sulphuric acid compound of copper. Copper sulphate or sulphate of copper, also blue vitriol or blue- stone CuS04 + 5Aq, is formed by the action of strong H2S04 on copper. It is a blue crystalline efflorescent salt, giving off its water of crystallization on heating, and appears then as a white, powder. CuS04 is an emetic, principally used in phosphorus poisoning. What compound results when a solution of CuS04 is treated with NH,0H ? A greenish-white precipitate is at first thrown down, which dissolves in an excess of the NII4OH with a deep-blue color. This solution is known as the solution of ammonio-sulphate of copper, and a dry salt of that name is also officinal. What is copper nitrate ? Cupric nitrate Cu(NO.j)2 ; a crystalline salt, of dark-blue color, readily soluble in alcohol and water, and decomposed by heat into cupric oxide. Describe the compounds of copper with arsenic. Copper arsenite Cu(AsO,)2, also called Sebeele’s green, is a bright-green powder, precipitated by treating copper solutions 120 ESSENTIALS OF MEDICAL CHEMISTRY. with sodium or potassium arsenite. Schweinfurth or Paris green is an insoluble green crystalline powder, representing a mixture of acetate and arsenite of copper ; both of these com- pounds are extremely poisonous, and the latter especially is used extensively for destroying insects on plants (potato bugs, etc.). Which is the principal carbonate of copper ? The greenish-blue precipitate resulting when a solution of cop- per is treated with an alkaline carbonate ; it is a basic carbonate of copper, CuC03Cu(0II).2, also occurring in nature as malachite of a beautiful green color. What are the two acetates of copper ? Cupric acetate or diacetate Cu(C2H.i02)2 -+- Aq ; large bluish- green crystals, and acetate of copper, cupri subacetas U. S., also called verdigris or rnrugo, consisting of a mixture of three different basic acetates of copper, which occur in masses of pale- green or bluish color. What are the poisonous properties of copper ? Pure copper is non-poisonous, but the commercial variety is rarely free from arsenic. Pure copper should not stain if boiled in HC1; copper vessels are often soldered with Pb and Sn, and these may prove poisonous. Food decaying in copper vessels often generates poisonous ptomaines. Copper is probably dis- solved by food from all copper vessels, but this is so little that it does no harm, but if the vessels corrode, and the food takes up the compounds, poisonous symptoms may arise. What are the symptoms of poisoning by copper compounds ? Vomiting and metallic taste of vomit; color, resembling that of bilious vomit, greenish ; turning blue on addition of IIN4OII; purging, tenesmus, colic pains, suppression of urine, and jaun- dice. What are the antidotes for acute copper poisoning ? Iron by hydrogen, eggs, and demulcents. Describe the symptoms of chronic copper poisoning. These are frequently met with in malachite and copper CHEMISTRY 127 workers; they exhibit a green line on the gums, lassitude, de- bility, tenesmus, and diarrhoea. Which articles of food may give rise to copper poisoning ? Pickles, peas, and string-beans are sometimes colored with copper salts. Dentist’s gold mixed with it may cause it, also spoiled flour corrected with Cu compounds, and jellies, sweet- meats, preserves, and fats left standing in copper vessels. How may copper compounds be recognized ? Metallic iron, such as needles or knives, dipped into articles containing copper compounds, become covered with metallic cop- per ; II2S gives with Cu solutions black precipitate, also ammo- nium sulpbydrate, NH,OH in excess strikes a deep blue color, and potassium ferrocyanide a brown precipitate. Mercury. What a *e mercury and its properties ? A bright metallic liquid Hg, a. w. 200, sp. gr. 13.6 ; volatile at all temperatures ; boils at 360° C. ; forms alloys with almost all metals ; remains unaltered in the air, but oxidizes at or near its boiling-point. What two classes of compounds does Hg form ? Like copper it forms “ous”and “ie” compounds, being divalent in the “ic” and monovalent in the “ ous” compounds, the mole- cules of the latter however seem to be regarded as double for- H0=(C,Hs),0. How do the alcoholic radicals behave chemically ? Like the metals. How is ether produced on a large scale ? In two reactions. 1. Ethyl alcohol is acted on by II2S04, the alcoholic radical takes the place of one II of II2S04, forming ethyl-sulphuric acid. C2H6OH -f- H2S04 = C2H5HS04 —{— H20 = Ethyl-sulphuric acid= c,!>so.. ' 2. The ethyl-sulphuric acid (sulphovinic acid) with another molecule of alcohol forms the oxide of two ethyl radicals and sul- phuric acid is set free again. C,II5HS04+C,H50II=C,H5-0-C2HR-fH2S04. Does ethyl-sulphuric acid act by catalysis, and what is cata- lysis ? It does not act by catalysis. Catalysis means the action by the presence of a body, and is really chemically an undefined term. Is the term sulphuric ether for ether a correct one ? No ; because it contains neither sulphuric acid nor sulphur. What are the properties of ether? It is a colorless, limpid, mobile liquid, of sharp burning taste and a characteristic ethereal odor, sp. gr. 0.723, boils at 34.5° C., slightly soluble in water ; it is highly inflammable, and when mixed with air it is explosive. CHEMISTRY, 157 In regard to their use as anaesthetics, what is to be observed with ether and chloroform respectively ? Ether can be administered without access of air, but chloroform should always be administered with access of air ; ether is in- flammable, both in substance and its vapors as well. Chloroform is not inflammable. What are mixed ethers ? Ethers that have two different alcoholic radicals ; e. g., methyl- ethyl ether. CH,-0-00. v21a5 What are compound ethers ? Compound ethers, sometimes termed esters, are compounds containing one univalent alcoholic radical united by oxygen to a monobasic acid radical. What do these compounds correspond to? To the salts of inorganic bodies, the alcoholic radical repre- senting the electropositive, the acid radical the electronegative, both united by oxygen. Give the reaction for the formation of acetic ether or ester. C2H5OH+CaH3O.OH=gA0>0=C2H3OAH5. In making acetic ether or compound ethers of weaker acids what has to be done ? Alcohol. Acetic acid. Acetic ether=ethyl acetate. A little sulphuric acid has to be added to make first ethyl- sulphuric acid ; this in turn is converted into H.,S04, the acid radical taking its place. C.,II- V C.ILHSO.+CyLO.OH = ' )0+II,S04. C.,ILCr What is nitrous ether, and how formed? By the action of nitrous acid on alcohol. C2II C,H5OH+imO,-C,H5N02= NCr Alcohol. Nitrous ether. 158 ESSENTIALS OF MEDICAL CHEMISTRY. Into which Pharmacopoeial preparation does this enter ? Into the spiritus retheris nitrosi, which should contain 5 per cent, nitrous ether and 95 per cent, alcohol. What compound amylic ether is largely employed in medicine ! c5nn. The amyl nitrite CJI, ,110.,= )0 formed by the action NCK of nitrous acid on amylic alcohol. C5H110H+HN0,=C5Hn-0-N0+H20. Describe the properties of amyl nitrite and its use in medicine. It is a yellow liquid, sp. gr. 0.877, boils at 95° C., insoluble in water, soluble in alcohol; when diluted it has a pleasant, but con- centrated suffocating odor, flushing the face by paralyzing the peripheral capillaries and thereby relieving cardiac tension ; it is used in angina pectoris, also in asthma, 5-6 drops being in- haled. Where are the compound ethers profusely found in nature ? As flavors in fruits and essential oils. Can these flavors or oils be produced artificially ? They can be produced artificially to resemble the natural flavors very closely. If judiciously employed they are not neces- sarily injurious. Which essential oil can be artificially produced ? The oil of wintergreen, which is principally methyl salicylate, ch3 ;0, and can scarcely be distinguished from the artificial C,IIs0/ product. What are fats considered chemically ? Fats are, in their chemical construction, ethereal salts or com- pound ethers and are acted on by alkaline hydrates like these. The process in the case of fats is termed saponification, and the product soap. CHEMISTRY. 159 What is an aldehyde? Dehydrogenated alcohol in which O11 takes the place of HO and an additional H. Aldehydes. c2h5oh+o=c2h4o+h2o CH3 c3h,o=co^ XH What is methyl aldehyde ? O II Formic aldehyde, CH20=H— C—H, so called because it is formic acid 0H2O2 minus O, and can be converted into this by oxidation. What is ethyl aldehyde, and what else is it called ? C2IItO ; it is also called acetic aldehyde or acetaldehyde, be- cause it is acetic acid minus O, wn, and by what reaction recognized? They are known as the biliary acids, and recognized by the Pettenkofer’s reaction. How is the Pettenkofer’s reaction applied, and what has to be done when used for testing urine or blood ? A minute quantity of cane sugar is added to their solutions, and this floated on H,,S04 in a test-tube, when a fine purple color will appear at their line of contact. In applying this to urine or blood, the fluids must be evaporated, the residue extracted with alcohol, and this mixed with ether, the precipitate resulting is dissolved with water and tested as above. What is lGucine ? Amido-caproic acid, CH3(CH2)3.CH.NH,COOH = CeH]3H02, found in the urine of those suffering from hepatic diseases, prin- cipally in acute yellow atrophy, appearing as spheres under the microscope. What other substance is associated in such conditions with leu- cine in the urine ? Tyrosine, C9HnN03, appearing under the microscope as stellar bundles or sheaves. What is creatine and what creatinine ? Creatine, C4H9H303, methyl glycocyamine, is another amido- acid found in the animal organism, especially in the juice of mus- cles, and also in the brain, blood, and amniotic fluid. Creatinine, C4II7N'hO, a product of dehydration of creatin, is normally pre- sent in the urine, and obtained from this as a zinc compound by precipitation with zinc chloride. When the hydrogen of ammonia is substituted by electronega- tive or acid radicals, what results ? Amides, thus acetamide is CHaO.NHa; if respectively one or Taurocholic acid. Cholic acid. Taurin CHEMISTRY. 187 more of the II of NII;j, they form primary, secondary, or tertiary amides; if a multivalent acid radical replaces one II in more than one group of they are termed R di- or R tri-amide. What is carbonyl di-amide ? J vriT Carbamide or urea, CO"<^jj'2= CON2H4, an isomere of am- nium cyanate, NII4.CON. How does urea originate in the body, and how is it excreted ? Urea is the final product of elimination of all nitrogenous food entering the body ; it is principally eliminated by the kidneys in quantities of about 500 grains daily ; more or less influenced by the amount of albuminous food ingested and the condition of the skin, bowels, and kidneys. What are the properties of urea ? It is neutral, odorless, of a cooling bitter taste, very soluble in water and alcohol, insoluble in ether; it crystallizes in four- sided transparent prisms with bevelled edges ; it forms crystalline compounds with acids, bases, and salts. How is the oxalate or nitrate of urea prepared from the urine ? By acidulating condensed urine either with oxalic or nitric acid, crystals of urea oxalate, (CH4N20)2C2H204-f-2Aq, or urea nitrate, CH4N20.HN03, separate on cooling. What is the compound of urea with mercuric oxide ? A white precipitate of the formula CH4N20.3Hg0. How is urea decomposed by sodium hypobromite or hypo- chlorite? Into sodium chloride or bromide, carbon dioxide, water, and nitrogen. N,H4CO + 3NaBrO=3NaBr 4-C02+2H20+Na. In which way is this utilized ? In different processes for the quantitative determination of urea in the urine. What is the differential density or Fowler’s method for the de- termination of urea in urine ? The process of decomposing the urea therein with Labar- 188 ESSENTIALS OF MEDICAL CHEMISTRY. raque’s solution and comparing the loss of specific gravity, which is in direct proportion to the urea decomposed. How is this process carried out ? Take the specific gravity of the urine accurately, also that of the liquor sodse chloratse ; the latter multiply by 7, and to the product add the specific gravity of the urine; the sum of the two divided by 8 gives then the specific gravity of a mixture of 1 volume urine and of 7 of the hypochlorite solution. Then add 1 volume of urine to 7 of liquor sodse cldoratse, allow the mixture to stand for several hours until effervescence has ceased, and take the specific gravity of the mixture; this subtracted from that representing the mixture before reaction gives the difference, which, if multiplied with 0.77, corresponds to the percentage of urea present in the urine. On what process does Liebig’s method for the quantitative de- termination of urea depend ? On the formation of urea compounds with mercuric oxide, a standard solution of mercuric nitrate being used with sodium bi- carbonate as an indicator. How is this process conducted ? Urine is deprived of its sulphates and phosphates with baryta water; after filtration it is titrated with the standard solution of mercuric nitrate, an excess of which is indicated by the sodium bicarbonate. What is known as the Russell and West’s method for determin- ing the urea in urine ? That based upon the decomposition of the urea by either the alkaline hypobromite or hypochlorite of sodium, and measuring the volume of nitrogen evolved which is converted into weight, and as such corresponds in a certain ratio with the amount of urea decomposed. What apparatus is used for this purpose, and how is the process conducted ? It consists of a flask containing a test tube with the urine to be examined ; around this tube in the bottle is the NaCIO or CHEMISTRY. 189 NaBrO solution ; connected with a glass tube through its stopper is a rubber tubing communicating with an inverted graduated burette floating in a cylinder of water. When the flask with the tube is inclined so that the urine will mingle with the Na BrO or NaCIO solutions it is decomposed, the C0.2 being absorbed by the alkaline solution present Avhile the N enters into the graduated burette displacing the water therein and is so read off in c.c. ; these are converted into urea by multiplying with 0.0027, giving in grams the urea present in the urine decom- posed. How is the alkaline sodium hypobromite solution (Knop’s solution) prepared ? 100 grams NaOH are dissolved in 250 c.c. water, and to this 25 c.c. bromine are added. In order to have accurate results what must be done ? The volume of nitrogen read off must be corrected for baro- metric pressure and temperature. What formula is used for this purpose ? yi _ v (b—w) 760(1+0.00366 t.) in which V’= is the volume required ; v= volume observed ; b= barometric pressure ; w= tension of aqueous vapor ; t= observed temperature centigrade. How does urea split up under the influence of the micrococcus urea ? It unites with water and forms ammonium carbonate. In which morbid conditions is the amount of urea increased in the urine, and in which diminished ? During increased metabolism ; in febrile and inflammatory- affections it is increased, also in the different forms of diabetes ; in acute yellow atrophy of the liver it may be entirely absent; in acute and chronic forms of Bright’s disease it may he greatly diminished, causing low sp. gr. of the urine, and giving rise to uraemia from being retained in the circulation. C0K2H4+2H,0=(NHJ8C03. 190 ESSENTIALS OF MEDICAL CHEMISTRY. What is uric acid, and in what form is it derived from the urine ? It is a compound urea, derived from the urine as a colored microscopical crystal of lozenge shape, either solitary or in clusters, the angles corresponding to the shortest diameter being rounded off. Does uric acid occur free in the urine normally ? It does not occur free in normal urine but as salts, sodium, potassium, or ammonium urate ; these are also found in the blood during gout and in fevers. What is the clinical significance of the presence of free uric acid in the urine ? When present at micturition or shortly afterwards it may give rise to the formation of gravel. How does uric acid form in the system ? As result of suboxidation of albuminoids, as an incomplete product in the formation of urea. Of what are gout stones principally composed ? Sodium urate. What are the properties of pure uric acid ? A white crystalline powder, odorless and tasteless, very little soluble in water, dissolving without decomposition in strong II.,S04, from which it is precipitated on addition of water; it is a dibasic acid forming with the alkaline bases both normal and acid salts. What is the solubility of uric acid ? 1 in 15,000-18,000; it is the most insoluble product of tbe body. Why do urates form deposits in joints and cartilages? Because they are poorly supplied with blood, which is a solvent for them. What is the reaction of blood during gout ? It is less alkaline than normally. CHEMISTRY. 191 Why are alkalies indicated in gout ? Because they increase the alkalinity of the blood so as to favor the elimination of the urates. What diet and manner of living favor the formation of uric acid ? Red meats, heavy wine, rich food, and lack of exercise. How is uric acid recognized chemically ? By the murexide test; to apply this dissolve the substance to be examined in a few drops of II£T03, the solution is then re- duced to dryness by gentle heating, leaving a yellowish residue ; if this is moistened with NH4OII a beautiful purple color, murexide, is developed if uric acid is present. How is the amount of uric acid in urine determined ? 200-300 c.c. mine are acidulated with 5-10 c.c. HC1 and allowed to stand for 24 hours when the crystals formed are col • lected and washed on a tared filter; the dried filter being weighed, the increase of weight gives approximately the amount of uric acid. Alkaloids. What are alkaloids ? Nitrogenized vegetable compounds of basic character, form- ing salts with acids, by directly combining with them like am- monia. How are they subdivided ? According to their physical condition into volatile and fixed alkaloids; those containing no oxygen are mostly liquid and volatile ; others containing it are solid and non-volatile. What are they chemically ? Tertiary (like the quinoline and pyridine bases) and secondary amines as far as they have been studied. How do alkaloids behave towards solvents ? The free or basic alkaloids are generally insoluble or very little soluble in water, but soluble in ether, chloroform, amylic alcohol, 192 ESSENTIALS OF MEDICAL CHEMISTRY. benzin, carbon bisulphide, alcohol, and acids ; as salts they are insoluble in these, but as a rule soluble in water. Have all plants different alkaloids ? Different plants may have identical or analogous alkaloids, several natural orders having similar or analogous ones; one plant may have a number of them ; thus nux vomica has three, ignatia has three, cinchona four, opium about twenty-one, etc. Which are the general characteristics of alkaloids ? They are alkaline ; form precipitates with tannic acid, form- ing insoluble tannates (for that reason tannin is used as an anti- dote for them); they are precipitated also by the fixed alkalies, also by phospho-tungstie acid, ammonium molybdate, potassium iodo-hydrargyrate, platinic chloride, picric acid, etc. Why is it difficult to separate and determine poisonous alkaloids from cadavers ? Their separation is intricate and requires delicate manipula- tion ; then they are present as a rule in minute quantities only; they are besides generally subject to decomposition during the decay of the body, and finally their differentiation from ptomaines offers great difficulty, as they often possess the same color reac- tions, and in some instances similar physiological effects. What must be done to establish the identity of an alkaloid? All the color tests must answer, besides the physiological action and taste. On what depends the Staas-Otto method for extracting alka- loids ? Upon the fact that their acid salts are soluble in water, and can be rendered insoluble therein by alkalies as free bases; as such they are taken up by ether or chloroform, amylic alcohol, carbon bisulphide, etc., and from these recovered by evaporation of the solvents. Which are the principal liquid alkaloids ? Nicotine C16H14N„ coniine CbII15N, piperidine CaHuN, and sparteine C15H.,6N.2. CHEMISTRY. 103 From what plant is nicotine obtained, and what are its proper- ties? It is obtained from tobacco ; it is a colorless oily liquid of characteristic odor, is very poisonous, producing nausea, cold sweats, giddiness, cardiac depression, and difficulty of respira- tion. Treatment: wash out the stomach with a strong infusion of tea, charcoal, and stimulants. Where is coniine obtained from, and what are its properties ? Coniine is obtained from hemlock (conium U. S); it is a color- less volatile liquid, of strong alkaline reaction, and penetrating odor. With HC1 its vapors give rise to white clouds, as is also the case with NH,; it is a powerful poison, causing paralysis of the muscles of the extremities, and when reaching the muscles of respiration death ensues from apnoea. Treatment, as in nicotine poisoning, with artificial respiration. Which are the principal alkalo:ds from cinchona? Quinine, quinidine, cinchonine, and cinchonidine. What is quinine, and how recognized ? Quinine, is in its basic state an amorphous white powder ; it is freely soluble in acids, with which it forms crys- talline salts, the sulphate being the one most in use ; its acid solutions are lluorescent; treated with chlorine it turns green on the addition of NH4OH, or red if potassium ferrocyanide is added. Which are the principal opium alkaloids, and with what acid are they united in opium? Morphine, codeine, narceine, narcotine, etc., united with rae- conic acid, as meconates in the natural state. What is morphine, and what its properties ? An alkaloid of opium, Cl7IIli)NO.!-]-Aq, crystallizing in trun- cated prisms of alkaline reaction, combining with acids to form salts. The alkaloid is insoluble in ether and chloroform, very little soluble in water, more so in alcohol, and also in acetic ether; its salts are soluble in water and alcohol; insoluble in acetic ether. 194 ESSENTIALS OF MEDICAL CHEMISTRY. Which are the symptoms produced by morphine poisoning ? Regular breathing, moist skin, livid lips, blue nose; further on irregularly rhythmical (Cheyne-Stokes) breathing, and coma. This is always an alarming symptom, but recovery is still possi- ble, and the efforts to restore the patient should not be given up. How does morphine or opium in toxic doses affect the pupils ? They are contracted ; other alkaloids, such as eserine, aconi- tine, and strychnine, produce the same effect, but the general symptoms produced by them are different. It is to be remem- bered however that in apoplexy, involving the Pons varolii, the pupils are also contracted as in opium poisoning. How soon may death result from morphine poisoning? Symptoms may come on in from 15-30 minutes to an hour or three hours; dry pills may not produce effects for 0-12 hours. Death may take place in 45 minutes, but usually not before 8-10 hours. What is the treatment of poisoning by morphine or opium ? Use the stomach pump ; if early enough emetics, mustard, salt and water, and zinc sulphate ; if no emesis is induced by these in a short time they must be abandoned. Wash out the stomach with strong tea, give animal charcoal, use faradism and artifi- cial respiration, flagellation with wet towels, to keep up respi- ration by reflex irritation, best to the region of the trigeminus, keep the patient moving and awake, strong coffee, enemata with brandy ; atropine is good as a respiratory stimulant. By which tests can morphine be recognized? IUSr03, orange-yellow color, shading off into yellow, Fe^Cl(i, greenish-blue. Iodic acid is reduced by morphine, rendering color of solution brownish from free iodine, changing to bluish- black on addition of starch water. What is tested for in looking for opium, and how? Meconic acid ; this gives a red color with ferric chloride, ex- tinguished bjr stannous chloride, but not by mercuric chloride. What is strychnine, and its properties ? An alkaloid extracted from nux vomica and ignatia, crystal- CHEMISTRY. 195 lizing in various modified forms of octahedra and four-sided prisms, which latter predominate. It is odorless, but of very- bitter taste, and said to be recognizable when so dilute as 1 in 100,000, and can be readily recognized 1 in 50,000, and 1 in 10,000 it is distinctly bitter ; it is soluble in 7000 parts of water, 1 in 1000 carbon disulphide, 1 in 340 ether, 1 in 100 alcohol, and 1 in 10 chloroform ; it is markedly basic and stable. Which is the principal salt of strychnine ? Strychnine sulphate St4H2S04; it does not char or color w'ith H,S04; dissolves in 10 parts of water and 60 alcohol; it is the principal ingredient in various vermin killers, and is largely used for destroying animals. What symptoms does strychnine produce in poisonous doses? Tetanic spasms ; muscles of respiration are rigidly con- tracted, producing a sensation of suffocation; every muscle becomes contracted, lasting from minute; opisthotonos, broad grin, great pain, lockjaw, respiratory muscles and dia- phraghm fixed, pupils contracted, dilating with relaxation of spasm; spasms come more and more rapidly until the victim dies of asphyxia and exhaustion. What is the fatal dcse of strychnine and its effect on infants? Fatal dose 1-2 grains, but recovery has been reported from 40 grains. Infants may be poisoned by strychnine through the mother’s milk, though the mother is not affected ; this is attri- butable to the more irritable spinal cord of children. How are cases of strychnine poisoning to he treated? Give the usual antidotes for alkaloids, but if the patient resists or cannot take them on account of spasm, put him partially under the influence of chloroform and then give emetics and antidotes. If emetics fail what is to be done ? Use the stomach-tube through perforated gag to prevent the patient from hiting it during spasm, and inject through this strong infusions of oak bark or tea or solutions of tannin, and wash out the stomach thoroughly. 11)6 ESSENTIALS OF MEDICAL CHEMISTRY. What are physiological antidotes for strychnine ? Chloroform, chloral, bromides ; chloral by rectum 30-60 grains as required. How may strychnine be recognized? By the bitter taste, 1 in 10,000 or 5000 must give it distinctly ; the bitter taste is even more delicate than the color test; if it is not bitter it is not strychnine, but though bitter it may be some- thing else ; H.,S04 produces no change with strychnine, but by the action of nascent oxygen it gives rise to a play of colors from blue to purple, violet, crimson, and orange-yellow. How is nascent oxygen generated in the color-test for strych- nine? By HS^04, to which is added a small fragment either of potas- sium bichromate or permanganate, or else manganese dioxide or lead peroxide. What is known as the Marshall Hall’s test? The physiological test; it is done by injecting some of the sus- pected liquid subcutaneously into a small frog ; if strychnine is present the animal will have tetanic spasms, etc. What is brucine and its properties ? It is an alkaloid associated with strychnine in nux vomica and ignatia, frequently contained in the strychnine of the market; in action it only represents about dn the strength of strychnine; test for brucine is IINOa with which it turns bright red (brucine is also a test for IINO;j). Which alkaloids derived from the solanacese are isomeric? Atropine, from atropa belladonna, analogous to daturine from datura stramonium, hyoscyamine from liyoscyamus niger, and duboisine from duboisia myoporoides, all of which have the formula C]7II,.jN03 and similar effects, dilating the pupils, and therefore termed mydriaties. What is atropine? An alkaloid of atropa belladonna, probably existing asa malate in the plant (daturine may be considered as analogous to it); CH KMISTKY. 107 it is soluble in 400 parts of water, is of alkaline reaction, and freely soluble in alcohol, ether, and chloroform. What is homotropine ? A synthetical product obtained from tropine and mandelic acid ; it is employed as a substitute for atropine. What are the symptoms of poisoning by atropine ? Giddiness, drowsiness, thirst, incoherent speech, and almost loss of articulation, dry mouth and throat, strong pulse, occa- sional vomiting, flushed face (erythema), dilated pupils, delirium, ischuria, coma, but death not usual ; cause of poisoning most frequently from eating the berries of the deadly nightshade. What antidotes should be employed in cases of poisoning by atropine ? Emetics, zinc sulphate, apomorphine hypodermically; stom- ach-pump if these fail; wash out the stomach with strong infu- sions of tea, oak-bark, or tannin solutions, and charcoal. By which test can atropine be recognized ? With H2S04 and a fragment of potassium bichromate it gives rise to an’odor of orange blossoms or attar of roses and a green color. What is the principal alkaloid of aconitum napellus ? Aconitine, C33H43NO]2, producing numbness and tingling of mouth, fauces, and extremities, cardiac failure, and death by syncope. The physiological effect on the tongue is the best test for its detection. Antidotes, same as for other alkaloids, to- gether with cardiac stimulants. What are ptomaines ? The basic products derived during the process of decay of cadaveric bodies. What are leucomaines ? The basic products derived from organized bodies during life by the retrograde chemical process. Are the ptomaines constant chemical bodies ? No, they vary according to the stage and the conditions super- vening during decay, and are quite unstable. 198 ESSENTIALS OF MEDICAL CHEMISTRY. How do the ptomaines compare with other amines ? Some of the well-known amines are produced during decay as ptomaines. Are they all poisonous, and by what terms are the poisonous ptomaines known from the non-poisonous ? They are by no means all poisonous ; but for those of a poison- ous character the affix of “ toxine” has been proposed, such as typhotoxine, etc. Name some of the known ptomaines. Neurine, neuridine, muscarine, cadaverine, mydseline, sep- sine, saprine, putrescine, collidine and hydrocollidine, myda- toxine, mydine and methylguanidiue, typhotoxine, and tyro- toxicon, etc. What is tyrotoxicon ? The poisonous ptomaine of putrid cheese and putrid decompo- sition of milk ; it is claimed to be a diazobenzol, C6Hr)N2C4H,02. Name some of the leucomaines. Guanin, xanthin, hypoxanthin, creatin, and creatinin. Proteids. What are proteids or protein bodies ? Albuminoids or albuminous bodies constituting the principal component of the animal organism, and also present in plants and seeds. How are they chemically constituted ? Their molecules have a very complex composition, but always contain nitrogen. In which way can they be studied ? By their products of decomposition, resulting both from chemi- cal and putrefactive changes. What are the two principal states in which they occur ? In the soluble and insoluble state; the latter being derived from the former by heat and various chemical bodies ; the in- CHEMISTRY. 199 soluble albuminoids cannot be directly reconverted into the sol- uble. Of what elements are the albuminoids principally composed ? Carbon, oxygen, nitrogen, hydrogen, and sulphur. Which are the general tests for the recognition of albumi- noids ? With the alkaline cupric (Fehling’s) solution they give a violet coloration ; with strong nitric acid they give a yellow coloration, changing with ammonia water to a brownish-red on cooling; this is known as the xanthoproteic reaction ; with Millon’s re- agent they give a rose or red coloration. What are the two principal albumins ? Eggalbumen as occurring in white of eggs, and serumalbumin as present in the serum of the blood. How can these two be distinguished? Eggalbumen coagulates when shaken with ether ; serumalbu- min does not. What is serumalbumin ? In its dry state it is yellowish and transparent; it exists in solution in the serum of the blood and other fluids of the body, and pathologically also in the urine at times. Are other albuminoids besides serumalbumin secreted from the urine at times ? Serumalbumin is the principal one, but globulin, albuminose, peptone, hsemialbuminose, and mucine may also be present in urine under certain conditions. What changes may serumalbumin undergo in the urine ? It may be changed by alkalies into alkali-albumin and by stronger acids into acid-albumin, both of which are not coagu- lable on boiling ; if the urine is alkaline from ammonia or other alkalies it has to be neutralized and rendered slightly acid. Which are the two most reliable tests for detecting albumin in urine ? Boiling and the contact method with IINO:i. 200 ESSENTIALS OF MEDICAL CHEMISTRY. How is the boiling test performed ? If urine is not acid render it so with a drop or two of acetic acid (if too much acid is added, uneoagulable acid-albumin is formed). Heat the upper portion of the urine in the test-tube, so as to have two strata for comparison, and if at or near the boiling-point a coagulum or turbidity results, albumin is present. What is the contact method (Heller’s), and how applied ? It is a ready and accurate method for bedside testing, and very reliable. Put a small quantity of urine into a test-tube, and, after inclining the latter, carefully pour in a little nitric acid so that there will be two distinct layers ; if albumin is pre- sent there will be a cloudy zone between the acid and the urine. How may this reaction be simulated ? If the patient has been taking copaiba, which, however, will become apparent by its odor. How may the quantity of albumin in urine be approximately expressed for clinical purposes ? By the proportion of the bulk of precipitated albumin after standing for 24 hours to the total volume of the fluid employed, as, for instance, \ or albuminous layer, etc. How much albumin is usually in the urine of albuminuria, and what is the greatest amount that can be in it ? It is rarely present in more than 1,0 per cent., but may rise to 1 and even 4 per cent. How is the quantity of albumin in the urine approximately de- termined with Esbach’s albuminometer ? By precipitating it with acidulated solution of picric acid in a graduated tube which indicates the relation of the volume of its precipitate to dry albumin, as follows : fill the tube to U with the urine and add picric acid solution to It, let stand for 24 hours, after which read off according to the graduation the amount of dry albumin contained in a liter of urine. What may give rise to the presence of albumin in urine ? Renal disease, characterized by the presence of casts, also blood or pus from some part of the uropoetic apparatus. CHEMISTRY. 201 Are traces of albumin in urine always indicative of renal lesions? No, unless casts are also found. How are blood and pus best detected in the urine ? By the characteristic appearance of their corpuscles under the microscope. How do albuminoids split up in peptic digestion ? They are considered to contain a hemi- and anti-group, the former splitting up into antialbumose and antipeptone, the latter into hemialbumose and hemipeptone. What is peptone, and its destination ? It is a soluble albuminoid, noneoagulable by heat or nitric acid, resulting in consequence of peptic digestion ; it is intended to be reconverted by the function of the liver into serumalbumin, if this is not accomplished it may circulate as such and be ex- creted by the kidneys without causing serious trouble to health. If it is excreted in large quantities it causes peptonuria, detected by overlaying Fehling’s solution with urine, when a roseate color will appear on the line of contact. What is mucin ? A substance resembling albuminoids, but containing no sul- phur ; it is a product of the mucous membranes, precipitated by dilute UNO., but not by strong. It is not coagulated by heat, soluble in alkalies, but precipitated by acids ; from urine con- taining it in solution it is precipitated best by acetic acid. Which are the principal globulins, and what do they form ? The metaglobuhn or fibrinogen and the paraglobulin or fibrinoplastin ; they form in the presence of fibrin ferment the coagulated albuminoid fibrin. What is fibrin ? A white elastic substance, which separates from blood on standing but does not pre-exist as such in it. What is alka'i albumin ? A modification of albumin produced by the action of alkalies on solutions of albumin ; it is present in the blood, chyle, mus- 202 ESSENTIALS OF MEDICAL CHEMISTRY. cles, etc. ; it is uncoagulable by boiling and contains no sulphur. What is acid albumin ? Syntonin, albumose, or parapeptone ; it is obtained when solu- tions of albumin are treated with acids, and is not coagulable by boiling. What is casein ? An albuminoid found in milk resembling alkali albumin but containing sulphur ; it is not coagulated by boiling but precipi- tated from its solutions by rennet and acids. What is gelatin, and how obtained? Gelatin is the collagen of white connective tissue ; it is amor- phous, translucent, yellowish, almost colorless and tasteless, swells up in cold and dissolves in hot water, cooling into a jelly. It is insoluble in alcohol and ether but soluble in glycerin ; it is precipitated from its solutions by tannin but not by alum. It is obtained from bones, tendons, etc., the collagen of which is by boiling with water converted into gelatin. Coloring Bodies. How may the soluble pigments of the body be regarded as form- ing? Originally from the blood coloring matter, haemoglobin, chang- ing to hsematin and hsemotoidin, this to the biliary pigments bilirubin and biliverdin, while the hydrobilirubin of the faeces may be considered identical with the urobilin of the urine. What is haemoglobin ? Haemato-globulin, haematocrystallin, cruorin, or erythrocruo- rin, is a crystalline substance of complex composition contain- ing all the elements of albumin plus iron. Where is it found ? In the red corpuscles of the blood. Describe its properties. It is a crystalline solid, not diffusible, of red color, capable of CHEMISTRY. 203 existing in two modifications, as oxyhsemoglobin and reduced haemoglobin or haemoglobin ; the former being scarlet-red and the latter purplish. It is soluble in water and alkaline solu- tions, and insoluble in alcohol and ether. How can oxyhsemoglobin and reduced haemoglobin be distin- guished ? By the spectroscope ; the absorption spectrum of the former exhibiting two bands, in D and E, while the latter shows one band between D and E. When and how do the changes in haemoglobin take place ? The oxyhaemoglobin in the tissues gives off some of its oxygen, and forms hsemoglobin, which in the lungs takes up oxygen, and again forms oxyhsemoglobin. What is the function of haemoglobin ? To carry oxygen to the tissues. How is oxyhaemoglobin changed in watery solution ? Into methsemoglobin, another modification, recognized by its absorption spectrum, which exhibits a band between C and D and two more, a larger and a smaller, between D and E. When haemoglobin is treated with dilute acids or alkalies vhat results ? It is decomposed into globin or globulin and a ferruginous pigment hsematin. This, according to its acid or alkaline state, gives two different spectra, of which the acid hsematin exhibits two bands, one between C and D, and a larger one between D and E; the alkaline hsematin exhibits one band only, between C and D and closer to the latter. Keduced hsemoglobin treated as the former produces reduced hsematin, recognized by two bands, one between D and E, and another to the right of E. What effect has carbon monoxide on haemoglobin ? It produces carbonic oxide hsemoglobin, recognized by exhib- iting two bands in the spectrum similarly situated as those of oxyhsemoglobin, but the right is narrower than that of the latter. Carbonic oxide hsemoglobin besides is a stable compound, and cannot be reduced as the oxy-modideation. 204 ESSENTIALS OF MEDICAL CHEMISTRY. How can haemoglobin be recognized? By the ozone test, which is applied by adding to the suspected liquid a few drops of fresh tincture of guaiaeum, giving it a milky- white color; upon adding to this, and shaking it with a little old spirits of turpentine or ethereal solution of hydrogen peroxide, an indigo-blue color is developed if haemoglobin is present; this may be equally as well applied to dry-blood stains. Which is the best test for haemoglobin? The haemin test. This consists of taking some of the suspected liquid, coagulating it by boiling with a drop of acetic acid; the coagulum after drying is mixed in a minute proportion with a trifle of sodium chloride on a microscopic slide, a drop or two of glacial acid is then added, and it is brought to the boiling-point, when upon cooling there will be seen under the microscope char- acteristic purplish or brownish-red rhombic prisms or plates of haemin or lisematin hydrochloride (Teichmanu’s crystals). Under what two conditions may haemoglobin appear in the urine ? In hsematuria and haemoglobinuria. What is haematuria ? The pathological condition characterized by the presence of blood corpuscles in the urine. What is haemoglobinuria ? The pathological condition characterized by the presence of haemoglobin in solution in the urine without having corpuscular form. Haematoidin, what is it ? Yellow crystals occurring in old extravasations; its formula is C10H:!4YA, which makes it homologous with bilirubin, though they differ spectroscopically. Which are the two principal biliary pigments ? Bilirubin and biliverdin. How is bilirubin supposed to be derived from haematin ? By combining with water as follows :— 3(C32H:i6N4Fe06) + 3H20=6(CI(iHlsN,03) + 3Fe0. Hsematin. Bilirubin. CHEMISTRY. 205 What is bilirubin ? The principal coloring matter of the bile. What is biliverdin ? A modification, or rather an oxidized product of bilirubin, forming spontaneously when alkaline solutions of bilirubin are exposed. How are the biliary pigments recognized ? By Gmelin’s test. Describe Gmelin’s test. Add nitric acid to the suspected liquid, and if biliary pigments are present a green precipitate will form, which, on addition of more acid, gives rise to a play of colors from green, blue, violet, and red to yellow ; this is best shown if a few drops of bile or liquor containing it and nitric acid are allowed to flow together on a porcelain plate when the colors will appear at the line of contact. Which is the principal urinary pigment ? Urobilin, C3SH44N407, identical in composition with hydro- bilirubin, the modified biliary pigment in the faeces. What is the indican of the urine? A yellowish pigment, sometimes called uroxanthin, contained in some urines ; with HC1 it turns reddish-blue or blue from the formation of indigo ; chemically it is an indoxyl-potassium sul- phate, and originates from the indol of the faeces. Which pigment gives urine the brownish-black color of certain pathological conditions ? Uromelanin, a black coloring body corresponding to the choroi- dal pigment and that of melanotic tumors. APPENDIX. Table of Element?. j Symbols. Atomic valence. Atomic weight. j Symbols. Atomic valence. Atomic weight. Aluminium . . A1 iii 27 Nickel .... Ni ii, iv 58.6 Antimony Niobium . . . Nb iii, v 94 (Stibium) . . Sb iii, v 119.6 Nitrogen . . . N i, iii,v 14 Arsenic .... As iii, v 74.9 Osmium . . . Os ii,iv,vi, viii 195 Barium .... Ba ii, iv 136.8 Oxygen .... o ii 16 Beryllium Palladium . . . Pd ii, iv 106.2 (Glucinum). . Be ii 9.1 Phosphorus . . P iii, v 31 Bismuth . . . Bi iii, v 207 Platinum . . . Pt ii, iv 194.3 Boron .... B iii 10.9 Potassium Bromine . . . Br i, iii, v, vii 79.8 (Kalium) . . K i 39 Cadmium . . . Cd ii 111.9 Rhodium . . . Rh ii, iv 104.1 Caesium .... Cs i 132.7 Rubidium . . . Rb i 85.3 Calcium .... Ca ii 39.9 Ruthenium . . Ru ii.iv, vi.viii 104.2 Carbon .... C iij iv 12 Scandium . . . Sc hi 44 Cerium .... Ce iii, v 141 Selenium . . . Se 11, IV, VI 78.9 Chlorine . . . Cl i, iii, v, vii 35.4 Silicium . . . Si iv 28 Chromium . . Cr ii, iv 52.4 Silver Cobalt .... Co ii, iv, vi 58.6 (Argentum) Ag i 107.7 Copper (Cuprum) Cu ii 63.2 Sodium Didymium . . D iii 144.6 (Natrium) . . Na i 23 Erbium .... Eb iii 165.9 Strontium . . . Sr ii, iv 87.3 Fluorine . . . F i 19 Sulphur .... ii, iv, vi 32 Gallium .... Ga iii 69.8 Tantalum . . . Ta V 182 Gold (Aurum) . Au i, iii 196.2 Tellurium . . . Te ii, iv, vi 126 Hydrogen . . . n i 1 Thallium . . . T1 i, in 203.6 Indium .... In iii 113.4 Thorium . . . Th iv 232 Iodine .... I i, iii, v, vii 126.6 Tin (Stannum) . Sn ii, iv 117.5 Iridium . . . Ir ii, iv 192.5 Titanium . . . Ti IV 48 Iron (Ferrum) . Fe ii, iv, vi 55.9 Tungsten or Lanthanum . . La iii 138.2 Wolfram . . w ii, iv, vi 183.6 Lead (Plumbum) Pb ii, iv 206.4 Uranium . . . U iv; vi 239 Lithium . . . Li i 7 Vanadium . . V iii, v 51.2 Magnesium . . Mg ii 23.9 Ytterbium . . Yb iii 173 Manganesium . Mn ii, iv, vi 54.8 Yttrium . . . Y iii 89 Mercury . . . Zinc Zn ii 64.9 (Hydrargyrum) Hg ii 199.8 Zirconium . . . Zr iv 90 Molybdenum . . Mo ii, iv, vi 95.8 207 208 APPENDIX. Weights and Measures. METRIC AND ENGLISH WEIGHTS. 1 milligram = 0.001 gram. = 0.015 gr. Troy. 1 centigram = 0.01 “ = 0.154 “ “ 1 decigram = 0.1 “ = 1.543 “ “ 1 gram = = 15.434 grs. “ 1 decagram = 10 grams = 154.34 “ “ 1 hectogram = 100 “ = 3.53 ozs. “ 1 kilogram = 1000 “ = 35.27 “ “ 1 grain Troy, = 0.0648 gram. 1 drachm Troy, — 3.888 grams. 1 ounce “ = 31.103 “ 1 “ Br. P. = 28.35 1 “ Avoird. = 28.35 “ 1 pound Troy, 12 oz. = 373.242 “ 1 “ Avoird. =453.6 “ 1 millimetre = 0.001 metre = 0.03937 inch. 1 centimetre = 0.01 “ = 0.3937 “ 1 decimetre = 0.1 “ = 3.937 inches. 1 metre = = 39.3704 “ 1 decametre = 10 metres = 32 ft. 9.7 “ 1 hectometre = 100 “ = 328 “ 1 inch. 1 kilometre — 1000 “ = 3280 “ 10.4 inches. METRIC AND ENGLISH MEASURES. 1 inch = 0.0254 metre. 1 foot = 0.3048 “ 1 yard = 0.9144 “ 1 rod = 5.0292 metres. 1 furlong = 201.1662 “ 1 mile = 1609.3297 “ METRIC AND APOTHECARIES’ FLUID MEASURES. 1 millilitre, cubic centimetre or C. C. = 0.001 litre = 16.23 minims. 1 centilitre = 0.01 “ = 2.71 fluiddraehms. 1 decilitre = 0.1 “ = 3.38 fluidounces. 1 litre = = 33.81 fluidounces. 1 decalitre = 10 litres = 2.6417 galls. 1 hectolitre = 100 “ = 26.417 “ 1 kilolitre = 1000 “ = 264.17 1 minim = 0.061c. c. 1 fluiddraehm = 3.7 “ 1 fluidounce = 29.6 “ 1 pint = 0.47 litre. 1 quart = 0.946 “ 1 gallon = 3.785 litres. 1 quart = 0.946 “ Rules for Converting Apothecaries’ into Metric Weights and Measures approximately. (According to Oldberg.) 1. To express quantities by weight of the Apothecaries’ system in metric terms, or to write medical prescriptions in metric weights. Rule A. Reduce each quantity to grains ; then divide the number by 10 (or move the decimal point one place to the left), and from the quotient subtract one-third. The remainder is in each case the num- ber of grams representing (nearly) the same quantity. Or, 209 APPENDIX. Rule B. Reduce each quantity to drachms, and multiply the num- ber by 4. The product is in each case the number of grams repre- senting (nearly) the same quantity. Or, Rule C. Reduce each quantity to ounces, and multiply the number by 32. The product is in each case the number of grams representing (nearly) the same quantity. 2. To express quantities by measure of the Apothecaries’ system in metric terms, or to write medical prescriptions in metric cubic measures. Rule D. Reduce each quantity to minims ; then divide the number by 10 (or move the decimal point one place to the left), and from the quotient subtract one third. The remainder is in each case the num- ber of cubic centimetres representing (nearly) the same quantity. Or, Rule E. Reduce each quantity to fluiddrachms, and multiply the number by 4. The product is in each case the number of cubic centi- metres representing (nearly) the same quantity. Or, Rule F. Reduce each quantity to fluidounces, and multiply the number by 32. The product is in each case the number of cubic centimetres representing (nearly) the same quantity. 210 appendix. Table of Equivalents of Centigrade and Fahrenheit Thermometric Scales. Cent. Fahr. Cent. Fahr. Cent Fahr. Cent. Fahr. Cent Fahr. Cent Fahr. o o O O O o O o O o o o —40 -40.0 -15 +5.0 +9 +48.2 +33 +91.4 +67 +134.6 +81 +177.8 39 38.2 14 6.8 10 50.0 34 93.2 58 136.4 82 179.6 38 36.4 13 8.6 11 51.8 35 95.0 59 138.2 83 181.4 37 34.6 12 10.4 12 53.6 36 96.8 60 140.0 84 183.2 36 32.8 11 12.2 13 55.4 37 98.6 61 141.8 85 185.0 35 31.0 10 14.0 14 57.2 38 100.4 62 143.6 86 186.8 34 29.2 9 15.8 15 59.0 39 102.2 63 145.4 87 188.6 33 27.4 8 17.6 16 60.8 40 104.0 64 147.2 88 190.4 32 25.6 7 19.4 17 62.6 41 105.8 65 149.0 89 192.2 31 23.8 6 21.2 18 64.4 42 107.6 66 150.8 90 194.0 30 22.0 5 23.0 19 66.2 43 109.4 67 152.6 91 195.8 29 20.2 4 24.8 20 68.0 44 111.2 68 154.4 92 197.6 28 18.4 3 26.6 21 69.8 45 113.0 69 156.2 93 199.4 27 16.6 2 28.4 22 71.6 46 114.8 70 158.0 94- <101.2 26 14.8 1 30.2 23 73.4 47 116.6 71 159.8 95 203.0 25 13.0 0 32.0 24 75.2 48 118.4 72 161.6 96 204.8 24 11.2 + 1 33.8 25 77.0 49 120.2 73 163.4 97 206.6 23 9.4 2 35.6 26 78.8 50 122.0 74 165.2 98 208.4 22 7.6 3 37.4 27 80.6 51 123.8 75 167.0 99 210.2 21 5.8 4 39.2 28 82.4 52 125.6 76 168.8 100 212.0 20 4.0 5 41.0 29 84.2 53 127.4 77 170.6 101 213.8 19 2.2 6 42.8 30 86.0 54 129.2 78 172.4 102 215.6 18 0.4 7 44.6 31 87.8 55 131.0 79 174.2 103 217.4 17 16 +1.4 3.2 8 46.4 32 89.6 56 132.8 80 176.0 104 219.2 Rules for Converting Centigrade into Fahrenheit. (D to stand for the degree to be converted.) D If above the freezing point of water, 32° F. (0° 0.), — X 9 4- 32. 5 If below freezing, but above 0° F.(—17.77° C.), 32— If below 0° F. (—17.77° C.) ")_32. '5x9' Rules for Converting Fahrenheit into Centigrade. (D—32) If above the freezing point of water, 32° F. (0° C.), -— X 5. (32—D) If below freezing, but above 0° F. (—17.77° C.) — x 5. If below 0° F. (—17.77° C.) — x 5. 9 INDEX. Acetaldehyde, 159 Acetic ether, 157 Acid, acetic, 161 glacial, 162 albumin, 202 amido-acetic, 185 amido eaproic, 186 arsenic, 81 arsenious, 81 beuzoic, 173 boric, 89 buytric, 162 camphoric, 169 carbolic, 171 carbonic, 92 eaproic, 162 cholic, 185 citric, 167 cyanic, 97 formic, 161 gallic, 184 gallotannic, 184 glyeocholic, 185 liippuric, 174 hydriodic, 66 hydrobromic, 65 hydrochloric, 62 hydrocyanic, 96 hydrofluoric, 66 hypophosphorous, 79 hyposulphurous, 71 lactic, 167 meconic, 194 metaboric, 89 metaphosphoric, 79 nitric, 75, 76 nitro-hydrochloric, 76 oleic, 163 orthophosphoric, 79 oxalic, 166 palmitic, 162 phosphoric, 79 phosphorous, 79 picric, 172 Acid, pyrophosphoric, 79 salicylic, 174 stearic, 163 sulphocyanic, 97 sulphuric, 70 Nordhausen, 72 sulphurous, 70 tartaric, 167 taurocholic, 185 tetraboric, 89 uric, 190 valerianic, 162 Acidimetry, 63 Acids, 44, 45 corrosive, 63 Aconitine, 197 Albuminoids, 198 Alcohols, 151 Alcoholic beverages, 155 Aldehydes, 159 Alkali albumin, 201 Alkalimetry, 100 Alkaline phosphates, separation from urine, 114 Alkaloids, 191 Aluminium, 133 hydrate, 133 oxide, 133 Alums, 134 Amido-acids, 185 Ammonia, 74 type, 46 Ammonium, 109 chloride, 110 carbonates, 111 cyanate, 97 hydrate, 110 hydrosulphide, 110 iodide, 110 nitrate, 110 nitrite, 110 sulphate, 110 valerianate, 162 Amidogen, 185 211 212 IN HEX. Amides, 46, 186 Amines, 46, 185 Ampere, 35 AmpSre-meter, 36 Amygdalin, 183 Amyl nitrate, 158 Amylose, 176 Analysis, 55 Aniline, 170 Anions, 39 Anode, 31 Anstie’s test for alcohol, 154 Anthracite, 91 Antidote for arsenic, 136 Antimon. et potas. tart., 88 Antimonium sulphuratum, 88 Antimony, 87 sulphide, 88 trichloride, 88 trioxide, 88 Aqua ammonise, 110 Aqua Tofani, 81 Archimedes, law of, 19 Argols, 103 Armature, 27 Aromatic group, 169 Arseniates, 81 Arsenic, 80 disulphide, 81 pentasulphide, 81 pentoxide, 81 tribromide, 81 trichloride, 81 tri-iodide, 81 trioxide, 81 trisulphide, 81 Arsen ites, 81 Artiads, 42 Atmosphere, 72 vitiation of, 93 Atom, 40 Atomic weight, 41 Atoms, linking, 44 Atropine, 196 Auric chloride, 145 Aurous chloride, 145 Axis, magnetic, 25 Balances, chemical, is Barium, 115 chloride, 115 hydrate, 115 nitrate, 115 Barium, oxide, 115 Barometers, 73 Bases, 44, 45 Battery, magnetic, 27 Benzaldehyde, 174 Benzene, 169 Benzyl hydrate, 173 Benzylic alcohol, 173 Biliary acids, 186 Bilirubin, 204 Biliverdin, 205 Bismuth, 142 bromide, 143 chloride, 143 iodide, 143 nitrate, 144 oxychloride, 143 subcarbonate, 144 subiodide, 143 subnitrate, 144 trioxide, 143 Bismuthyl, 143 Bituminous coal, 91 Boettger’s test for glucose, 143. 180 Boiling test for albumin, 200 Borax, 89 Boron, 89 Bromethane, 151 Bromine, 65 oxides of, 65 Brommethaue, 149 Bromoform, 150 Brucine, 196 Butyric fermentation, 154 Butter, 165 of antimony, 88 Butterin, 166 Bunsen’s element, 33 pALCIUM, 111 \J bromide, 112 carbonate, 114 chloride, 112 fluoride, 112 hydrate, 112 hypochlorite, 64 iodide, 112 oxide, 111 phosphates, 113 sulphate, 113 Calland’s element, 33 Calomel, 128 Calorie, 21 INDEX. 213 Calx sulpliurata, 113 Camphor, 168 Cane sugar, 178 Caoutchouc, 168 Carbamide, 187 Carbohydrates, 175 Carbon, 90 dioxide, 91 disulphide, 95 monoxide, 91, 94 skeleton, 147 Carbonic oxide haemoglobin, 203 Casein, 203 Cast-iron, 135 Catechol, 173 Charcoal, 90 Celluloid, 176 Celluloses, 175 Chemism, 40 Chemistry, 40 Chloral, 159 hydrate, 160 Chlorethane, 151 Chlorides in water, determination of, 58 Chlorinated lime, 112 Chlorine, 61 oxyacids of, 64 Chloroform, 150 Cholesterin, 174 Chromic acid, 140 oxide, 140 Chromium, 140 tri oxide, 140 Chyluria, 165 Cinchonidine, 193 Cinchonine, 193 Colloids, 137 Collodium, 176 Coloring bodies, 202 Conductors, 28 Coniine, 193 Compound ethers, 157 Copper, 124 acetates, 126 alloys, 124 ammonio-sulphate, 125 arsenite, 125 carbonate, 126 chlorides, 125 nitrate, 125 sulphate, 125 sulphide, 125 Correction of gases for pressure and temperature, 73 Corrosive sublimate, 129 Cream of tartar, 103,167 Creatine, 186 Creatinine, 186 Crystallization, system of, 67 Crystalloids, 137 Cupric hydrate, 124 oxide, 125 Cuprous oxide, 124 Current, electric, 34 Cyanogen, 95 gas, 95 DANIELL’S element, 32 Declination, magnetic, of needle, 26 j Davy's safety lamp, 148 1 Determination of chlorides, 105 I Determination of organic matter in water, 58 Determination of phosphoric acid in urine, 114 Determination of sulphates in urine, 107 Dextrin, 177 Diamagnetism, 27 Dialysate, 137 Dialyzed iron, 137 Diamond, 90 Diastase, 153 Dichlorethane, 151 Dichlormethane, 149 Dicyanogen, 95 Diffusate, 137 Digitalin, 184 Direction of galvanic current, 31 Distillation, 56 Donovan’s solution, 82 EARTHY phosphates, separation from urine, 113 Eggalbumen, 199 Electric light, 36 machines, 29 Electricity, resinous, 28 vitreous, 28 Electro-chemical characterof atoms, 41 Electro-magnetism, 36 214 INDEX. Electrolysis, 38 Electrolytes, 39 Electrometer, 30 Electromotive force, 34 series, 34 Electrophorus, 29 Electroscope, 28 Elements, 40 classification of, 48 Equations, chemical, 42 Equivalence, 41 Esbach’s method for determining albumin in urine, 200 Esters, 157 Ethane, 148 Ethers, 155 Ethylic alcohol, 152 Ethyl aldehyde, 159 hydrate, 152 sulphuric acid, 156 Ethylic ether, 156 Extract of malt, 153 FARADISM, 37 Fats, 158, 164 Fehling’s solution, 180 test, 180 Fermentation, 152 Ferments, 152 Ferric chloride, 138 ferrocyanide, 139 hydrate, 84,136 nitrate, 139 oxide, 138 sulphates, 139 Ferrous and ferric compounds, 136 bromide, 138 carbonate, 139 chloride, 138 iodide, 138 ferric oxide, 138 hydrate, 136 oxide, 138 phosphate, 139 sulphate, 138 sulphide, 69, 138 Fibrin, 201 Fire-damp, 148 Fleitmann’s test, 85 Fluorine, 66 Formula, chemical, 42 Formulae, empyrical, rational, gra- phic, 43 Fossil coal, 91 Fowler’s method for determining urea, 187 Fowler’s solution, 82 Franklinism, 28 Galena, 119 Galvanic batteries, 32 elements, 32 Galvanism, 31 Galvano-cautery, 36 Galvanometer, 36 Gas carbon, 91 Gelatin, 202 Glass, 98 Globulins, 201 Glucose, 179 Glucoses, 175 Glucosides, 183 Glycerin, 163 Glycocol, 185 Glycogen, 177 Glycol, 166 Gmelin’s test, 205 Gold, 144 Gram, 18 Graphite, 90 Gravity, specific, 19 Grenet cell, 33 Grove’s element, 33 Gums, 177 Gutta percha, 168 Gypsum, 113 204 Haematoidin, 204 ILematuria, 204 Hsemin test, 204 Haemoglobin, 202 Haemoglobinuria, 204 Haines’ test for glucose, 180 Halogens, 60 Heat, 20 latent, 22 specific, 21 Heller’s test for albumin, 200 Homologous series, 146 Homotropine, 197 Hydracids, 45 Hydrates, 45 Hydrobilirubin, 205 Hydrocarbons, 91, 146 INDEX. 215 Hydrogen, 50 antimonide, 87 arsenide, 80 peroxide, 60 sulphide, 68 Hydrometers, 20 Hydroquinone, 173 Hydroxides, 45 INCLINATION of magnetic needle, 1 26 Indican, 205 Indoxy 1-potassium sulphate, 205 Induced current, 37 Induction, electric, 29 magnetic, 25 Insulators, 28 Intensity of current, 35 Iodine, 66 Iodoethane, 151 Iodoform, 150 Iodomethane, 149 Iron, 135 by hydrogen, 135 Isomerism, 97 JOHNSON’S picric acid test for glucose, 181 KATHIONS, 39 Kathode, 31 Kermes mineral, 88 Knop’s solution, 189 T ABARRAQUE’S solution, 64 JU Lactic fermentation, 153 Lactose, 178 Laevulose, 178 Lampblack, 90 Laughing gas, 74 Law of conductivity, 28 of electric attraction, 29 of magnetic attraction, 26 Lead, 119 acetate, 121 carbonate, 122 chloride, 121 chromate, 121 hydrate, 120 in water, testing for, 59 iodide, 121 Lead, nitrate, 121 oxides, 120 subacetate, 122 sulphate, 121 sulphide, 121 Lecithin, 166 Leclanche element, 33 Leucine, 186 Leucomaines, 197 Leyden jar, 30 Liebig’s method for determining urea, 188 Lime, 111 chloride of, 61 chlorinated, 64 slaked, 112 water, 112 Lines, neutral, 25 Liquid alkaloids, 192 Liquor acidi arseniosi, 82 arsenici et hydrarg. iodid., 82 potassse, 100 potass, arsenit., 82 sodae, 104 sodii arseniatis, 82 Lithium, 109 bromide, 109 carbonate, 109 Liter, 17 Loadstone, 25 Magnesia, ii6 Magnesium, 116 carbonates, 117 chloride, 117 hydrate, 117 oxide, 116 phosphates, 117 sulphate, 117 Manganese, 134 dioxide, 135 Manganous sulphate, 135 Magnetism, 25 hypothesis of, 26 Magnets, temporary, 25 Marsh’s test, 86 Menthol, 169 Mercuric chloride, 128 iodide, 129 nitrate, 130 oxide, 128 sulphide, 130 Mercurous chloride, 128 216 INDEX. Mercurous iodide, 129 nitrate, 130 oxide, 128 sulphide, 130 Mercury, 127 ammoniated, 129 Mercury, cyanide, 130 Metals, 48 Metamerism, 97 Methane, 147 Methyl, 149 alcohol, 151 aldehyde, 159 hydrate, 151 saiicylate, 158 Methj'lic alcohol, 151 Metre, 17 Milk, 165 Minium, 121 Mixed ethers, 157 Molecular weight, 47, 48 Molecule, 22, 40 condition of, 22 Molecules, binary, 43 naming of, 43, 44 ternary, 43, 44 Monobasic acids, 161 Moore’s test for glucose, 180 Morphine, 193 Mucin, 201 Murexide test, 191 Naphthalene, 174 Naphthols, 175 Nascent state, 61 Needles, astatic, 27 Nickel, 140 Nickelous bromide, 140 Nicotine, 193 Nitrates in water, 59 Nitrobenzene, 170 Nitrogen, 72 dioxide, 75 monoxide, 74 oxides of, 74 pentoxide, 75 tetroxide, 75 trioxide, 75 Nitroglycerin, 164 Nitrous ether, 157 Non-conductors, 28 metals, 48 Notation, chemical, 40, 42 OHM, 35 Ohm’s law, 35 Oil of turpentine, 168 Oleates, 163 Olefins, 166 Olein, 164 Oleomargarin, 166 Opium alkaloids, 193 Organic matter in water, 57 Organized ferments, 152 Orpiment, 81 Oxidation, 52 Oxides, 52 of chlorine, 64 Oxyacids, 45 Oxygen, 52 Oxyhaemoglobin, 203 Oxyhydrogen flame, 53 Ozone, 54 PALMITIN, 164 Pane rea tin, 153 Paraffin, 149 Paraffins, 146 Paraldehyde, 159 Paramagnetism, 27 Parchment paper, 176 Paris green, 82, 126 Pepsin, 152 Peptone, 201 Perissads, 42 Petroleum, 148 Pettenkofer’s test for biliary acids, 186 Phenol, 171 Phenyl, 169 hydrate, 171 Phosphates, normal, neutral, and acid, 79 Phosphine, 78 Phosphorus, 76 oxides of, 78 red, 76 Platinic chloride, 145 Platinum, 145 Polarization, 182 of plates, 32 Poles, magnetic, 25 Polymerism, 97 Potassium, 99 acetate, 103 acid sulphate, 192 tartrate, 103, 167 INDEX. 217 Potassium, bicarbonate, 103 bromate, 101 bromide, 101 carbonate, 103 chlorate, 102 chloride, 101 chromate, 102, 140 citrate, 103 cyanide, 101 dichromate, 102,141 ferricyanide, 98 ferrocyanide, 98 fluoride, 101 hydrate, 101 hypochlorite, 102 iodide, 101 nitrate, 102 oxalate, 103, 166 permanganate, 102, 135 silicate, 98 sulphate, 102 sulphide, 101 sulphocyanide, 97 tartrate, 103 Potential, 34 Proteids, 198 Prussian blue, 98, 139 Ptyalin, 152 Ptomaines, 197 Purification of water, 59 Pyknometer, 19 Pyrocatechin, 173 Pyroxilin, 176 Quantity of current, 36 Quinidine, 193 Quinine, 193 Radicals, compound, 44 Rain-water, 56 Realgar, 81 Reinsch’s test, 85 Resistances, electric, 35 Resorcin, 173 River-water, 57 Roberts’ method for determining sugar in urine, 182 Rochelle salt, 108 Ruhmkorff coil, 37 Russell and West’s method for de- termining urea, 188 Saccharoses, 175 Salicin, 184 Salts, 44, 45 normal acid, basic, double, 46 of lemon, 166 Saltpetre, 102 Saponification, 164 Saturated hydrocarbons, 146 Scales, thermometric, 23 Scheele’s green, 82, 126 Serumalbumin, 199 Sewage in water, 57, 58 Silicon, 98 Silicic oxide, 98 Silver, 132 chloride, 132 monoxide, 132 nitrate, 132 sulphide, 132 Smee’s element, 33 Soaps, 164 Sodium, 104 bicarbonate, 108 bromate, 106 bromide, 106 carbonate, 108 chlorate, 106 chloride, 105 hydrate, 104 hypochlorite, 64,106 hyposulphite, 71 iodate, 106 iodide, 106 phosphates, 107 potassium tartrate, 108,167 silicate, 98 sulphate, 106 sulphite, 107 sulphocyanide, 97 urate, 190 Soluble ferments, 152 Spring-water, 56 Staas-Otto, method for extracting alkaloids, 192 Stannic chloride, 142 oxide, 142 Stannous chloride, 142 oxide, 142 Starch, 177 Stearin, 164 Steel, 135 Stibine, 47 Stoichiometry, 47 218 INDEX. Strychnine, 194 Sublimation, 56 Substituted ammonias, 185 Substitution compounds of hydro- carbons, 149 Sulphides, 69 Sulphur, 67 dioxide, 69 oxides of, 69 trioxide, 70 Symbols, 41 Synthesis, 55 Syrupus calcis, 112 Tannin, 184 Tartar emetic, 88 Taurin, 186 Tension, electric, 34 Terebenthene, 168 Terpenes, 168 Terpine hydrate, 168 Test for arsenic in substance, 84 Mitscherlich’s for phosphorus, 78 sodium chloride in urine, 105 Tests for lead, 123 Thermoelectricity, 30 Thermometers, 20, 23 Thermoscope, 22 Tin, 141 Toluene, 173 Tri-brommethane, 150 Trichloraldehyde, 159 Trichlormethane, 149 Tri-iodomethane, 150 Trinitroglycerin, 163 Trinitrophenol, 172 Triple-phosphate, 117 Trommer’s test for glucose, 180 Turnbull’s blue, 98 Turpentines, 168 Tyrosine, 186 Unsaturated hydrocarbons, 146 Uranium, 141 acetate, 141 nitrate, 141 Urea, 187 nitrate, 187 oxalate, 187 Urinometers, 20 Urobilin, 205 Uromelanin, 205 Uroxanthin, 205 VERDIGRIS, 126 Vermilion, 130 Vinegar, 162 Volatile fatty acids, 161 Volt, 34 Volumetric solutions, 63 WATER, 55 Water, alkaline, 60 carbonated, 60 chalybeate, 60 composition of, 55 hard, 56 permanently hard, 56 potable, 56 saline, 60 soft, 56 sulphur, 60 temporary hard, 56 Watertype, 45 Weight, 17 absolute, 17 apparent, 17 metric, 17 specific, 17 Well water, 57 White precipitate, 129 Wrought iron, 135 XANTHOPROTERIC reaction, 199 ZINC, 118 Zinc chloride, 118 hydrate, 118 oxide, 118 sulphide, 119 sulphate, 119 Now Heady—Fourth Edition. CONTAINING “HINTS ON DISSECTION.” Essentials of Anatomy and Manual of Practical Dissection. By CHARLES B. NAJSfCREDE, M.D., Professor of Surgery and Clinical Surgery in the University of Michigan, Ann Arbor; Corresponding Member of the Royal Academy of Medicine, Rome, Italy; late Surgeon Jefferson Medical College, etc. etc. With Handsome Full-page Lithographic Plates in Colors. Over 200 Illustrations. No pains or expense has been spared to make this work the most exhaustive yet concise Student's Manual of Anatomy anti Dissection ever published, either in this country or Europe. The colored plates are designed to aid the student in dissecting the muscles, arteries, veins, and nerves. For this edition the woodcuts have all been speci- ally drawn and engraved, and an Appendix added containing 60 illustrations representing the structure of the entire human skeleton, the whole based on the eleventh edition of Gray’s Anatomy, and forming a handsome post 8vo volume of over 400 pages. 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Cleveland Medical Gazette, Cleveland, Ohio, Sept. 18D2. “ Every well-equipped medical library should contain a good ‘Dictionary of Medicine.’ In the book before us nil the words commonly used in medicine and its various branches are given, with their pronunciation, accentuation, ''etymology, etc., followed by a clear and concise definition. The appendix, of some eighty pages, will prove of great aid to the busy practitioner. We bespeak for Keating’s New Dictionary of Medicine an extensive sale.” The Canada Medical Record, Montreal, Canada, Aug. 1892. “ A modern dictionary, thoroughly up to date, is a necessary addition to the medical library. We have no hesitation in recommending Keating’s for the purpose. 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In addition, however, there are features not included in other works of this class. The appendix is full, and will be found of great use for purposes of reference; and the work is likely to meet with great favor. We are glad to welcome its appearance on account of its distinctive features, and its handy and present- able form.” St. Louis Medical and Surgical Journal, St. Louis, Mo., Sept. 1892. “ A reliable guide to the definition of the majority of medical terms such as are found in current medical literature, including the later and as yet unfa- miliar names applied to operations, diseases, etc. Korni A—"2, 24, ’93—22m A few Professional Opinions of “A New Pronouncing Dictionary of Medicine,” by John M. Keatinq, M.D., LL.D. “ This superb work is placed on the right-hand side of my desk, there to remain as long as I am interested in the best ‘medical ’ literature.” (Signed) ALEX. J. C. SKENE, M. D., Dean of the Long Island College Hospital, Professor of Medical and Surgical Sept. 5, 1892. Diseases of Women, Long Island Medical College, Brooklyn, N. Y. “ I will point out to my classes the many good features of this book as com- pared with others, which will, I am sure, make it very popular with students.” (Signed) JOHN CRONYN, M. D., LL. D., Professor of Principles and Practice of Medicine and Clinical Medicine ; Aug. 23. 1892. President of the Faculty Medical Dept. Niagara University, Buffalo, N. Y. “ I am convinced that it will be a very valuable adjunct to my study table, convenient in size and sufficiently full for ordinary use.” (Signed) C. A. LINDSLEY, M. D., Professor of Theory and Practice of Medicine, Medical Dept. Yale University ; Aug. 15, 1892. Secretary Connecticut State Board of Health, New Haven, Connecticut. “1 have perused the work carefully, and am highly pleased with it. The phonetic method of pronunciation is complete and perfect. I have looked in vain in every other dictionary for the pronunciation of ‘ Micrococci,’ a word more frequently mispronounced than any other term in present use. I shall unhesitatingly recommend the work to my classes.” (Signed) J. A. CLOSE, M. D., Aug. 15, 1892. Professor of Principles and Practice of Medicine and Microscopy, St. Louis College of Physicians and Surgeons. “ I am much pleased with Keating’s Dictionary, and shall take pleasure in recommending it to my classes next winter.” (Signed) HENRY M. LYMAN, M. D., Professor of Principles and Practice of Medicine, Rush Medical College, Chicago, III. Aug. 5, 1892. “ My examination and use of it have given me a very favorable opinion of its merit, and it will give me pleasure to recommend its use to my class.’’ (Signed) J. W. II. LOVEJOY, M.D., Aug. 20, 1892. Professor of Theory and Practice of Medicine, and. President of the Faculty, Medical Dept. Georgetown University, Washington, D. C. ‘•A very good dictionary, and likely to be acceptable to medical men and students. Its price is moderate, and it contains a vast amount of information. Its special feature as a pronouncing dictionary will enhance its value to many. I will place it on our list of recommended ‘ medical dictionaries.’ ” (Signed) W. B. GEIlvIE, M. D., Aug. 15, 1892. Prof ssor of Principles and Practice of Medicine, Trinity Medical College, Toronto, Canada. NOW READY. Notes on the Newer Remedies THEIR THERAPEUTIC APPLICATIONS AND MODES OF ADMINISTRATION. BY DAVID CERNA, M.D., Ph.D., Demonstrator of and Lecturer on Experimental Therapeutics in the University of Pennsylvania, FORMING A SMALL OCTAVO VOLUME OF ABOUT 175 PAGES (7 x 5) INCHES. PRICE, - The work will take up in alphabetical order all the Newer Reme- dies, giving their physical properties, solubility, therapeutic ap- plications, administration, and chemical formula. It will, in this way, form a very valuable addition to the various works on Therapeutics now in existence. Chemists are so multiplying compounds that if each compound is to be thoroughly studied, investigations must be carried far enough to determine the practical importance of the new agents. Brevity and conciseness compel the omission of all biographical references. .FUST PUBLISHED. A MANUAL OF THE PRACTICE Or MEDICINE. BY A. A. STEVENS* A.M., M.D., Instructor of Physical Diagnosis in the University of Pennsylvania, and Demonstrator of Pathology in the Woman’s Medical College of Philadelphia. Post 8vo,, 502 pages. Illustrated. Price, Cloth $2.50 W. B. SAUNDERS, Publisher, PHILADELPHIA, PA. Contributions to the science of medicine have poured in so rapidly during the last quarter of a century, that it is well nigh impossible for the student, with the limited time at his disposal, to master elaborate treatises, or to cull from them that knowledge which is absolutely essential. From an ex- tended experience in teaching, the author has been enabled by classification, the grouping of allied symptoms, and the judicious elimination of theories and redundant explanations, to bring within a comparatively small compass a complete outline of the Practice of Medicine.