February. 1912. 



KNOWLEDGE. 



57 



U 



( 





c ^ 



make it obvious that the action of a druf^ nia\- 

 frequentl\- be foretold h\ investigating its decompo- 

 sition products and stability in the chemical 

 laborator\-. Whereas .\cetanilide, as previoush' 

 mentioned, has found an application in practical 

 medicine, two compounds belonging to the same 

 class, namely Eormanilide and l>en/anilide are quite 

 useless, since the former is far too readih acted upon 

 by reagents, and the latter 

 under similar conditions 

 is not appreciabl}' broken 

 down into reactive pro- 

 ducts. It has been 

 shown by numerous 

 workers that the stereo- 

 configuration of an 

 organic com|)(jund, i.e., 

 the spatial arrangement 

 of the component atoms 

 and grou|)s may exert a 

 profound infiuence on 

 its chemical properties: 

 thus the '■ ortho " and 

 " para " toluidines (which 

 differ only in the space 

 relationship between the 

 two substituent groups 

 in the benzene ring), 

 behave quite differently 

 towards reagents, the 

 former compound being 

 the less reactive of the 



two; corresponding with this difference in chemical 

 properties, the to.xicity of the "para" compound is 

 approximatelv twice as great as that of the "ortho" 





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o 



:> 







FlGUKli 61. 



Trypanosoines in Blood. 



Photographed from an excellent drawing made froiri 



an actual specimen. 



certain alkaloids, ether, and chloroform, found a 

 place in the first British Pharmacopoeia, and the 

 last edition contains details regarding a number of 

 synthetic com[)ounds, among which may be men- 

 tioned .\cetanilide. Phenazone, Salol, and Sulphonal. 

 .\l)art from the great advances in Pharmacology- 

 brought about by the researches of chemists and 

 ph\siologists, there has been a distinctl\- forward . 

 movement on the part 

 of pharmacists to place 

 within the reach of 

 medical practitioners 

 galenical preparations 

 of undoubted quality, 

 strength and elegance, 

 and this advance is 

 largely due to the 

 British Pharmaceutical 

 Conference. 



In the first edition of 

 the British Pharmaco- 

 poeia, previously referred 

 to, man\- tests are given 

 for impurities in inor- 

 ganic chemicals, but very 

 few standards are set for 

 drugs of organic origin ; 

 in the second edition 

 there is a distinct im- 

 provement in this 

 direction, which is main- 

 tained in a .striking 

 manner in the latest edition, in which directions are 

 given for the accurate standardization of a consider- 

 able number of tinctures and extracts — such as those 



^•^^^^ 



derivative. .\n importantexamplc of this phenomenon of nux-vomica, opium, belladonna and ipecacuanha, 



will be dealt with subsecjuentl\-. wlien the treatment 

 of sleei)ing sickness is discussed. 



This increasing use of isolated active principles 

 and definite chemical compounds in place of pre- 

 parations of uncertain strength and indefinite action, 

 is well demonstrated b\- a comparative study of the 

 three editions of the British Pharmacopoeia, when it 

 will be noticed that many of the old-fashioned con- 

 coctions are being gradually rei)laced by those which 

 are rational and scientific in their composition. As 

 an example we ma\' take two classes of preparation 

 typical of the old conditions of pharmacy, con- 

 fections (electuaries) and decoctions — the former are 

 semi-solid medicaments consisting of various drugs, 

 chiefly of vegetable origin, mixed together with 

 sweetening agents, such as honey, and the latter arc 

 made by boiling barks, roots, and so on, with water. 



The 1864 Pharmacoi)oeia includes seven confec- 

 tions and thirteen decoctions; the 1885 edition, a 

 much larger work, includes eight confections and 

 thirteen decoctions, and the latest edition, published 

 in 1895, mentions onl}- four confections and three 

 decoctions. In place of such as these there has 

 been an introduction of increasing numbers of 

 definite chemical substances into official pharma- 

 ceutical works; several such preparations, c.t;.. 



which contain as their active principles poisonous 

 alkaloids. In one special case — nux-vomica — the 

 pre[)arations are adjusted to contain a definite 

 percentage of strychnine instead of total alkaloids, 

 since it has been found that this alkaloid is far more 

 toxic and active than those with which it is 

 associated. In cases where no official standard is 

 set, various workers have described satisfactor\- 

 methods for obtaining uniform standards, which 

 are adopted by the leading manufacturing chemists. 

 While methods of chemical standardization are very 

 desirable, yet, in some instances, they are not quite 

 satisfactory, and in such cases physiological methods 

 are used : this applies more especially to those 

 preparations derived from digitalis, ergot, and 

 strophanthas, where an inactive drug might be 

 responsible for most serious results. .\11 this 

 valuable information with regard to the structure 

 and pharmacology of drugs would be of little use 

 in practical medicine but for the great accumulation 

 of knowledge regarding the cause of man\- diseases. 

 In this direction Lord Lister, Pasteur and Koch have 

 done pioneer work in proving conclusively that 

 definite diseases are frequently associated with 

 definite micro-organisms termed bacteria or bacilli, 

 which must be exterminated to elTect a cure. It 



