ON SPECIFIC THERAPEUTICS. 81 



LECTURE III. 



CHEMO-THERAPEUTIC STUDIES ON TRYPANOSOMES. 



THE studies on trypanosomes, which have of 

 late been carried out with the greatest energy, 

 especially in the Institut Pasteur in Paris, the 

 School of Tropical Medicine in Liverpool, and 

 the Speyerhaus in Frankfort-on-the-Main, are 

 of the greatest theoretical and practical im- 

 portance ; for in this field of study the patient 

 research work of Experimental Therapeutics 

 has first come into full activity, and at the same 

 time a basis has been gained on which we may 

 hope successfully to undertake the practical 

 attempt of suppressing sleeping-sickness. The 

 exceedingly great difficulty of these studies is 

 evidenced by the fact that hundreds and thou- 

 sands of substances have to be examined by 

 animal experiments, before a few producing a 

 therapeutic effect can be found. I myself have 

 in course of time examined more than 600 such 

 substances. From their effect on animals, hints 



G 



