366 Mr. Plimmer and Capt. Fry. Further Results of [June 28, 



Experiments in vitro performed with the Blood of a Normal Rat which had 



teen treated with Antimony. 



Experiments were made in order to ascertain whether the blood of a rat 

 which had been treated with antimony would show any active trypanocidal 

 powers in vitro. Although in the case of an infected animal all the 

 trypanosomes in the peripheral blood would have been destroyed in about 

 an hour, no noticeable trypanocidal effects were shown by the blood of a 

 treated rat in the following experiments. 



A normal rat had 5 minims of a 1 per cent, solution of lithium antimonyl 

 tartrate injected subcutaneously : its blood was taken at 15, 30, 60, and 

 70 minutes after the injection, and was mixed with an equal quantity of 

 blood from a Surra rat containing many trypanosomes ; the mixed bloods, 

 taken at the times mentioned, were examined under the microscope at 

 various intervals from 5 to 30 minutes after the mixing, and the 

 trypanosomes were found to be entirely unaffected, so that the blood of the 

 treated normal rat did not have any trypanocidal effect added to it by the 

 dose of lithium antimonyl tartrate. The Surra rat, whose blood was used 

 for this experiment, was then given 5 minims of a 1 per cent, solution of 

 lithium antimonyl tartrate : — 



Blood was taken and showed the following : 



10 minutes after injection... Trypanosomes affected : movement very rapid. 

 20 „ ... Many " battledores." 



40 „ „ ... Trypanosomes greatly decreased in number 



all " battledores." 

 60 „ „ ... Blood quite free from trypanosomes. 



A normal rat was given four doses subcutaneously, one every other day, 

 of 5 minims of a 1 per cent, solution of lithium antimonyl tartrate : 

 24 hours after the last dose a drop of its blood was mixed with a drop of 

 blood from a Surra rat in which trypanosomes were plentiful. The mixture 

 was watched under the microscope for half an hour, but no effect was 

 produced : the blood of the treated animal behaving just as the blood of the 

 control, an untreated rat. 



A normal rat was given subcutaneously 10 minims (a lethal dose) of a 

 1 per cent, solution of lithium antimonyl tartrate, and its blood was mixed 

 at half an hour, one hour, and one-and-a-half hours after the injection with 

 an equal part of an emulsion of trypanosomes prepared from the lungs, liver, 

 and heart's blood of a Surra rat just dead. Each of the mixtures was 

 examined up to 30 minutes, but no effect whatever was produced on the 



