94 



Drs. B. Blacklock and W. Yorke. 



Strains B and C the curves are again those of monomorphic trypanosornes 

 and correspond closely to those obtained from the rats, in Strain A the 

 curve has two widely separated main peaks, one occurring at 17-19/a 

 and the other at 25-27/i, and is typically that of a dimorphic parasite. 

 Apart then from the slightly greater average length of Strain B and the 

 prolongation of the cytoplasm along the flagellum in Strain C noted above, 

 we have been unable to discover any character which enables us to 

 distinguish these two strains. Both, however, are differentiated from 

 Strain A by the presence in the latter of posterior nuclear forms and by 

 the occurrence of typical " short stumpy " forms. These distinctive points 

 are more readily brought out by a study of the infections in guinea-pigs than 

 in rats. 



Table III. — Percentage of Short, Intermediate, and Long Forms in each of 



the Three Strains. 



Strain. 



Animal. 



Short and stumpy, 

 14-21 /x. 



Intermediate, 

 22-24 fx. 



Long, 

 25—36 fx. 



Eat 



Guinea-pig .... 



Total 



Eat 



Guinea-pig .... 



Total 



Eat 



Guinea-pig .... 



Total 



10 -o 

 35 -8 



22 -9 



5-2 

 7-2 



6 2 



10-4 

 14 -8 



12 -6 



( 13 -4 

 15 -2 



14 -3 



13 -6 

 20 -4 



17 -0 



24 -4 

 31 -2 



27 '8 



76 -6 

 49-0 



62 -8 



81 -2 

 72 -4 



76 -8 



65 "2 

 54 -0 



59 -6 



In view of these facts we must reconsider the nomenclature of the parasites 

 and decide which of them corresponds with the type to which the name 

 T. equiperdum was given. In order to determine this point it is necessary to 

 refer to the literature of the subject. 



In 1896, Bouget* described a trypanosome in the blood of an Algerian 

 horse which was suffering from Dourine. Bouget succeeded in infecting a 

 number of laboratory animals with the parasite, but, unfortunately, the 

 strain was lost shortly afterwards. Three years later (1899) Schneider and 



* " Contribution a l'Etude du Trypanosome des Mammiferes," ' Annales de l'lnstitut 

 Pasteur,' 1896,. vol. 10, p. 716. 



