82 EXPERIMENTAL RESEARCHES 



may be obtained as to what to avoid, and in 

 what direction therapeutics should advance. I 

 will not enter here into the details of my work, 

 but will only give you a general resume of the 

 chief results. 



The substances which have hitherto proved 

 efficient in combating trypanosome infections 

 can be divided into three groups, viz. : (i) The 

 group of the basic triphenyl-methane dyes ; (2) 

 The group of the benzidine dyes ; (3) The 

 group of the arsenicals. 



The salts of mercury may be used as adju- 

 vants to each of the foregoing. 



Among the triphenyl-methane stains, which 

 were first employed by Wendelstadt, para- 

 fuchsin is by far the most satisfactory. It is 

 possible, by prophylactic feeding with this drug, 

 to render mice resistant to trypanosome infec- 

 tions for a long time, and I believe that this 

 innocent substance might well be employed in 

 the Tropics for the prophylaxis of human 

 sleeping-sickness. 



As regards the second type of substances, 

 belonging to the benzidine group, trypan-red 

 is a cotton dye which shows the remarkable 

 property of staining mice an intense red, which 

 remains fast for months. I have also prepared 



