ETIOLOGY 413 



a dog will usuall)' produce the disease. The parasite disap- 

 pears from the blood and tissues very rapidly after death, 

 so that, to prove successful, inoculations should be made 

 from an infected individual before or immediately after death. 

 They are not affected after forty-eight hours. 



Schneider and Buffard, Nocard and others found the try- 

 panosoma in the blood and exudates of horses, asses and dogs 

 suffering from dourine. They failed to find it in the same 

 localities in animals of the same 

 species which were free from 

 dourine. The infected blood 

 preserved for 24 hours in sealed 

 glass tubes, and then inoculated 

 into dogs produced character- ~ "'' 



istic symptoms and lesions with 

 many trypanosoma in the blood. 

 Inoculation into two other dogs, 

 with the same material, but at 



the end of 48 hours, produced a 



1- V . . • 1 i_ • 1 Fig. ioq. Trvpanosoma of dou- 



slight transient hyperemia only, . ',, -^ .,:'.. 



rine in the process of division 

 without local lesions or propaga- (^^^^^ Lignil-res). 



tion of the parasite in the blood. 



The blood from the same animal inoculated after fifteen days 



gave negative results. 



Baldrey found Romanowsky's and Wright's modifications 

 of Leishman's method the best methods for staining the try- 

 panosoma ; the latter is very useful and handy, as no mixing 

 of solutions is necessary and no fixing required. 



The following is Romanowsky' s Stain : 



STOCK SOI.UTION NO. I. 



Hochst's Medicinal Methylene Blue ^ i part 



Sodium Carbonate pure 0.5 parts 



Distilled water 100 parts 



Place this solution in an incubator at 37° C. for two or three days, 

 when a purple color will be noticed at the edges of the liquid ; this 

 depends upon the formation of a new red color — methylene red — which 

 combined with eosin forms the active principle of the stain and has a 



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