150 



Scientific Proceedings (113). 



elaboration of a derivative many times more powerful in the 

 cure of protozoon infection. At present, a considerable amount 

 of work is being performed along the lines established by Ehrlich 

 and numerous organic arsenicals have been prepared, still, the 

 synthesis of new chemical compounds merely for the purpose of 

 testing their toxic and therapeutic properties and thereby finding 

 the best drug for the treatment of disease will not advance the 

 science of chemotherapy beyond mere empiricism. 



Is it impossible to find a relationship between certain atomic 

 groupings and toxicity or curative effect? Once the influence 

 of these various groups upon the parasite or the animal body is 

 appraised the synthesis of new compounds will assume a more 

 rational course. Some very valuable findings have already been 

 made in this direction by Ehrlich who discovered the remarkable 

 trypanocidal and spirillocidal effects of the arseno group (As = As) 

 when attached to the nuclear carbon atom. 



Our attention has been attracted to the influence of the 

 amino group upon toxicity and therapeutic effect when present 

 in organic arseno compounds. We confined our study to the 

 derivatives of 3, 3' diamino -4, 4/ dihydroxy arsenobenzene, the 

 dihydrochloride of which is the important remedy in syphilis 

 known as salvarsan or arsphenamine. When this substance is 

 converted into other compounds containing various substituents 

 in the amino group, the toxicity and curative properties are 

 influenced to such an extent as to lead to the assumption that the 

 amino group is as vitally essential as the arseno group. As an 

 illustration, let us consider a condensation product of arsphena- 

 mine with sodium formaldehyde sulphoxylate known as neo- 

 arsphenamine. As described in the patent papers and also in the 

 work of Raiziss and Falkov, 1 it is evident that substitution took 

 place completely in one amino group and partially in the second. 

 The work of Schamberg, Kolmer and Raiziss 2 and also Roth 3 

 show that the average maximum tolerated dose of this com- 

 pound is 0.254 milligrams per kilo of body weight, whereas that 



1 Journal Biol. Clicm., March, 1921. 



2 Schamberg, J. F., Kolmer, J. A., and Raiziss, G. W., A mer. Jour, of Med. 

 Sci., clx, No. 188. 



I Roth, G. B., Archiv. Dermal, and Syph., II, No. 3, 301. 



