The Trypanosomes causing, Dourine. 



95 



Buffard* found a try pari osome in two Algerian horses and an ass which 

 had Dourine. They succeeded in reproducing Dourine in a horse experi- 

 mentally after passage of the virus through a dog. This work was 

 subsequently confirmed by Nocard.t 



Doflein,J in his book on the parasitic protozoa, ] 901, refers briefly to 

 Rouget's description of the disease and to the morphology and pathogenicity 

 of the parasite. The photographs illustrating Doflein's article are apparently 

 reproductions of Rouget's original plates. Reference is made to Nocard's 

 work on the transmission of the disease by coitus, and also to the fact that 

 he believed the parasite to be identical with those causing Nagana and Surra. 

 Since, however, the disease was spread by coitus and the trypanosome failed 

 to infect ruminants, Doflein considered that the parasite described by Rouget 

 was distinct from those causing ISTagana and Surra and gave to it the name 

 T. equiperdum. It appears, therefore, that five years after the strain was 

 lost Doflein named the parasite purely on the description of the trypano- 

 some given by Rouget. Rouget's account of the morphology of the parasite 

 must then be regarded as the authentic description of T. equiperdum. 

 Unfortunately, in Rouget's original paper (loc. cit.) the account of the 

 morphology of the trypanosome is rather vague. Its length is given as 

 18-26//, and its breadth as 2-2 5//,. The parasite is described as terminating 

 in a free flagellum which forms about a fourth of the total length of the 

 creature. 



All subsequent authors agree that T. equiperdum is a monomorphic parasite 

 in which all forms are furnished with a free flagellum. The Frankfurt and 

 the East Prussian strains conform to this description. The strain brought 

 from Algiers by Hagenbeck and maintained at Berlin and here, under the 

 name T. equiperdum,, differs in important particulars from the classical 

 description of T. equiperdum, and from the other strains we have examined. 

 We must conclude, therefore, that the symptom-complex of the disease 

 clinically known as Dourine can be produced by more than one species of 

 trypanosome. 



It is important to record that we are unable to distinguish morphologically 

 the parasite of Hagenbeck's Dourine horse from T. rhodesicnse, T. pecaudi, or 

 T. vgandce (T. brucei of Uganda). Nevertheless, we hesitate to suggest that 

 it is identical with any, or all, of these, in view of the fact that it produced 

 in a horse symptoms clinically known as Dourine. That a trypanosome 



* " Le Trypanosome de la Dourine," 'Archives de Parasitologic,' 1900, vol. 3, p. 124. 

 + " Sur les Rapports qui existent entre la Dourine et le Surra ou le Nagana," ' Compt. 

 Rend. Soc. Biol.,' 1901, vol. 53, p. 464. 



% 'Die Protozoen als Parasiten und Krankheitserreger,' Aufl. I, p. 66, Jena. 



