Page:The New International Encyclopædia 1st ed. v. 04.djvu/662

* CHEMISTRY. musculaf iiiovcmonts involved in respiration, and the constant movements of the intestinal walls, involve a Iar>;e exjienditure of eneigj- which is quite independent of the cncrf;y required for muscular contraction wlicn somi* task is to be performed. I'onsciiuently. in the case of an ac- tive man, the amount of chemical activity in- volved in the various processes incidental to the liberation of the required energy is large. The ellicient and economical liberation of this energy in the body is dependent not only upon the comiilctcncss of digestion, tlic readiness of absorption and assimilation, and the efliciency of the circulation, but much depends also upon the projH'r working of the excretory apparatus. Waste ])roducts formed in oxidation must be removed, otherwise the physicdogical rliytlim is interfered with. The ashes and clinkers must be taken from the human furnace if the fires are to be kept burning freely. For this purjjose, the bkin, lungs, and kidneys are ellicient channels, and the study of the excretions poured out tlirough these several enumctories throws much light upon the (•xtcnt and character of the oxida- tion going on in the body. It is a truism that the chemical study of the urine throws light especially uptm the extent and character of the proteid metabolism going on in the body. TTie nitrogenous waste products — those which come from the breaking down of proteid nuiterial — • find their outlet through the urine, and abnor- malities in this excretion have a significance easy of interpi'etation. It must not be overlooked, in considering the domain of physiological chemistry, that its scope is a broad one. The chemical processes going on in the animal body, for e.xample, are multi- tudinous. There are few functions in which physiological chemistry does not play some part, and the light which its study throws upon pliysi- ology as a whole can hardly be estimated. The phenomenon of muscular contraction is in great part chemical. V'ntil the discovery of muscle- plasma and the contained myosinogen by Kiiline, j'hysiologists were in the dark regarding what took place inside the nuis(de-fibre during con- traction and after the death of the fibre. The discovery of glycogen in the liver by Claude Bernard, and the relationship of glycogen to the sugar of the blood, opened up the whole subject of the glycogenic function of the liver, and Iherebv paved the way for a clearer understand- ing of the function of carbohydrate material in the body. The subject of secretion and the mode of formation of the digestive enzymes from their precursors, the zymogens, inside the cells of the secreting glands, was unraveled in great part through the application of chemical methods by Buch eminent pliysiologists as Corvisart, Kiiline, Heidenhain, and Langley. The study of ]ym])h-formation was rendered possible through the use of chemical methods, and the same methods of study have taught ]iliysiologists all that is known regarding the chemical nature of the blood, its various chem- ical constituents, and the various parts played by the serum, plasma, and corpuscles in the co- agulntion of the blood and in many normal and abnormal processes. ^Metabolism in the liver — aside from glycogen- fonnation — has had much light thrown upon it by chemical methods of study, and the whole broad subject of internal secretion and the duct- 580 CHEMISTS AND DRUGGISTS. less glands has been helped forward at a rapid jiace by the wi>rk of physiological clu'mist.s, who have unraveled in ])art the chemical nature of the S])ecilic sulistances responsible for the jihysio- logical action of the various secretions. Lastly, mention may be made of the part which physiological chemistry is now playing in the deelopment of our knowledge concerning bacteriology and the infectious diseases. The micro-organisms which are responsible for the various infectious diseases now preying on man- kind owe their action in great part to specific chemical poisons which they ])roduce. The chem- ical nature and physiological action of these poisons is being carefully studied, and, with fuller knowledge of their properties, ready meth- ods for combating these diseases will be avail- able. Even to-day our knowledge of these toxins is considerable, and more than one antitoxin has been discovered by which imnuinity can be secured or a logical method of treatment devised. Here is a large and practical field for the appli- cation of the principles and nu'thods of ])hysio- logical chemistry, and we may ho]ic in the near future for such an extension of oir knowledge of bacterial poisons as will enable us to cope successfully with these destroyers of health and life. A study of physiological chemistry prom- ises expansion of knowledge concerning the nor- mal changes occurring in the organism, and also afi'ords a means of recognizing the approach of abnormal conditions, the forerunners of disease and death. BinLioGUAPnY. Waller and Symes, FAemen- iari/ riii/siological Chemislri/ (London, 1807); Bunge, Text-Iiook of Physioloiiival rnid I'atho- logical Chemist ri/, trans, by Woolbridge (London, 1890; new German ed. Leij)zig, 18!)4) : llainmar- sten, A Text-Hook of Physioloyicnl Chcmistri/, trans, by Mandcl (New York, 1803) ; Wurtz, Traitc dc chimie biologique (Paris, 1880-85) ; Salkowski, I'racticum der phi/siolofiischcn und patliolofiischen Chemie (Berlin, 1893) ; Iloppe- Scyler, Ilandhuch dcr phi/.iiologisch- und patho- logisck-clieinischoi Analyse fiir Arr:::tc und Studirendc (Berlin, 1893); Neumeister, Lchr- biich dcr physiologischen Chemie (Jena, 1897). The substances forming the chemical basis of the organisms of animals and plants nuiy be found described vnidcr their special nanu's. See also Food. CHEMISTS AND DRUGGISTS, Laws Re- Latim; III. In tlic I'liilcd States the terms apo- thecaries, druggists, ]iliarmacists. and sometimes chemists, are u.sed with little or no distinction as names of those licensed to compound and sell drugs aiul medicines upon prescriptions of physi- cians or otherwise; in Great Britain, liowcver, a legal distinction exists between the three classes — apothecaries, chemists and druggists, and phar- maceutical chemists. The law of 1S(!8, designed especially to restrict the sale of poisons, made the classification just referred to for the sake of public convenience. Under this law, apothe- caries form practically a lower branch of the medical ]U'ofcssioii. having the right to ju'actice in certain classes of cases; clicmists and drug- gists are those who have passed an examination at the pharmacy college, and have received a license to sell and compound drugs and poisons; jiliariuaccutical chemists are those who have passed a second, 'major,' examination, and who constitute a higher branch of the profession.