DRUGS 339 



by whom the British Pharmacopoeia (1914) is issued. But many 

 other chemical compounds used for medicinal or dietary pur- 

 poses have been the subject of experiment. Some have had 

 their utility established and have been adopted with practice, 

 while many others, after a brief notoriety, have returned to 

 oblivion. 



The discovery of new remedies depends more and more on a 

 combination of chemical and physiological knowledge. No better 

 illustration of this principle could be adduced than the case of 

 the remarkable compound " salvarsan," or 606, the use of which 

 was introduced into medicine by the late Professor Ehrlich. 1 



Salvarsan is an artificial chemical compound containing the 

 element arsenic in such a condition that it does not produce the 

 ordinary effects of arsenical poisoning. It possesses the property 

 of seeking out and destroying the specific organism of syphilis, 

 the spirochcBta pallida. 



Salvarsan does not represent the first attempt to use arsenical 

 compounds for medical purposes. Common white arsenic, the 

 arsenious oxide As 4 6 , has long been recognised as a valuable 

 alterative and tonic medicine when given in minute doses. It is 

 also known to act as a dangerous poison in quantities exceeding 

 a small fraction of a grain. Some fifty years ago cacodylic acid 

 (dimethylarsinic acid) 



OH 



was tried in cases of tuberculosis and arsenic acid itself was 

 reported to have some value. Later a number of arsenical 

 organic compounds were prepared by the French chemist 

 Bechamp and others. Among the rest a substance named 

 "atoxyl" was introduced into medicine. Its constitution was, 

 however, unknown and misrepresented till, in 1907, Ehrlich, in 



1 Paul Ehrlich was born of Jewish parentage at Strehlen, in Silesia, in 1854. 

 He studied medicine in the Universities of Breslau and Strasbnrg, and graduated 

 in the latter. He devoted himself to researches connected with the nature, 

 origin and treatment of diseases which are attributable to the presence in the 

 body of specific organisms such as tubercle, diphtheria and syphilis. His idea 

 appears to have been that each cell in the body, including bacterial parasites, 

 has a specific affinity for some particular substance. The blood stream may be 

 compared to a river containing a variety of fish, and the problem is to find a 

 drug which when introduced into this stream will kill the noxious while not 

 injuring the normal inhabitants. 



Ehrlich died on August 20, 1915. 



