1922] on The Search for Specific Remedies 637 



In the case of antimony and bismuth the production of complex 

 organic derivatives has been neither successful nor necessary. Rela- 

 tively simple salts, and even the free metal in a fine state of division, 

 have been found !;o possess valuable specific curative properties against 

 certain forms of infection. The most familiar of all antimony com- 

 pounds, tartar emetic, has proved to be a specific not only for a 

 protozoal infection, such as kala-azar, but for infection by the small 

 trematode worm Bilharzia ; but the mode of its action is still a 

 mystery. 



In the action of emetine, the chief alkaloid of ipecacuanha, on 

 amoebic dysentery, we have another example of a curative effect which 

 cannot be explained by a direct killing of the parasites. Other 

 alkaloids can be found, and even derivatives of emetine itself, which 

 are more harmful to the aincebas outside the body, much less 

 poisonous to man than emetine, but devoid of curative action 

 on human amoebic dysentery. Emetine, moreover, is powerless to 

 check the course of an artificial infection produced in a kitten with 

 ameeba3 from a case of human dysentery, w 7 hich readily yields to 

 emetine treatment. Again we are forced to the conclusion that the 

 co-operation of the body of the host is an essential factor in the 

 curative action. 



The discovery of the nature of this co-operation, by the body of 

 the infected animal, in the action of the many artificial specific 

 remedies now available, would appear to be an essential step towards 

 a more orderly advance in this field of investigation. 



[H. H. D.] 



WEEKLY EVENING MEETING, 



Friday, April 7, 1922. 



Sir James Reid, Bart., G.C.Y.O. K.C.B. M.I). LL.D., 

 Vice-President, in the Chair. 



Sir Ernest Rutherford, LL.D. D.Sc. F.R.S. M.R.I. 



Evolution of the Elements. 



[Absteact deferred.] 



