1909.] Experimental Treatment of Trypanosomiasis. 363' 



the periods of time necessary to ensure immobility and death of the 

 trypanosomes can be ascertained. By a comparison of the results obtained 

 a very good estimate of the probable action of any drug when given to an 

 affected animal can be arrived at. 



for instance, sodium and lithium antimonyl tartrates were found to act, in 

 the same dilutions, in a manner fairly comparable to their antimony content,, 

 and to their action on the trypanosomes in an affected animal. Again, with 

 atoxyl a much higher concentration of the drug was necessary — it had to be 

 about ten times stronger — in order to obtain the same destruction pictures,, 

 results corresponding with the rapidity of the disappearance of trypanosomes 

 from the peripheral blood of affected animals when treated with the above 

 drugs. 



In the case of the two new lactates mentioned above, their therapeutical 

 value was accurately foretold by a preliminary study of their action in vitro 

 in the manner described. In all these experiments controls have been 

 carried out : it has been found that trypanosomes will live and retain their 

 activity for hours when infected blood and the diluting fluid alone are mixed 

 together. 



The various changes taking place in trypanosomes on coming into contact 

 with a dilute trypanocidal drug, commencing with their preliminary extra- 

 ordinary increase of activity, and their subsequent swelling up, immobility,, 

 and disintegration, can be watched in all their different stages in this, 

 manner. These effects resemble very closely the changes which take place in 

 the trypanosomes in the peripheral circulation of an animal treated with 

 antimony. 



The following tables show the effects produced by the different substances 

 in their various dilutions. 



Dilutions of sodium antimonyl tartrate in 0"89 per cent, salt solution 

 mixed with Surra rat's blood, in equal parts. The control in all cases is 

 equal parts of blood and 089 per cent, salt solution. 



Dilutions. 



Time. 



Control. 



1—500. 



1—1000. 



1—5000. 



1—10,000. 



Motionless 



Motionless 



Pew active forms 



Trypanosomes active 



1 min. 



Very active. 



» 



33 



Motionless 



Pew active forms ; 



10 mins. 



33 









rest sluggish 







33 



33 



33 



All sluggish 



30 „ 



33 



» 



33 



33 



Motionless 



1 hour 



33 



