1909.] Experimental Treatment of Trypanosomiasis. 367 



trypanosomes. These experiments may be compared with those recorded 

 on p. 356. 



Experiments with Antimony upon Dogs. 



Since the date of the last paper a large number of experiments have been 

 made with antimony in various forms upon dogs suffering from Surra. Of 

 the five dogs mentioned there one remains alive and well at the present 

 date, more than a year after inoculation. 



Our experiences with dogs show that they are extremely susceptible both 

 to the disease and also to antimony : they are therefore not quite suitable 

 animals for these experiments, although they have all lived many times the 

 length of the untreated disease, that is 14 days. Five of the dogs were 

 treated with small doses of sodium antimonyl tartrate in their drinking 

 water, but the disease is so acute in dogs that this method of giving the 

 drug, although it appeared to have some effect in postponing the reappearance 

 of the trypanosomes in the blood, did not produce results sufficiently 

 encouraging to warrant further experiments. 



With regard to the experiments made with metallic antimony suspended 

 in egg-yolk, the initial experiment was so encouraging as to make a further 

 trial necessary. In this case the dog at the first relapse was given 

 20 minims of a 2\ per cent, suspension : there was no local reaction, which 

 in dogs is of frequent occurrence after the administration of antimony in 

 any form, and the trypanosomes, which were very numerous, were entirely 

 absent from the blood in 24 hours ; the dog remained quite free from them 

 for 48 days, and gained 3 lbs. in weight, and appeared perfectly well. The 

 recurrence was very sudden, as the dog was perfectly well up to the moment 

 when he was seized with a series of fits which ushered in the recurrence, 

 from which he did not recover. A rat treated at the same time as this dog 

 with 5 minims of the same suspension is alive and well more than 100 days 

 after this one dose. 



Many of the dogs mentioned in the table below have died with fits and 

 paralyses and other nervous symptoms, but we are not certain whether these 

 are due to the disease or to the antimony. In certain of the dogs the 

 treatment has appeared to alter the acute disease into a chronic one, and in 

 one of these more chronic cases there was a considerable excess of cerebro- 

 spinal fluid and a cellular exudation around the vessels in the brain, very 

 similar in incidence and extent to that described and figured by one of us 

 in rats dead from infection with Trypanosoma gambiense* 



There is a curious uncertainty in the local effects produced in dogs by 

 * ' Eoy. Soc. Proc.,' B, vol. 79, p. 95. 



