56 WALKER. 



by either Salvin-Moore and Breinl or Fantham. The trypano- 

 some bends upon itself ventrally and becomes fused into a round, 

 binucleate body, around the border of which the flagellum re- 

 mains for a time attached, but is later cast off. This method of 

 development, therefore, corresponds more nearly with the forma- 

 tion of the schizonts of Schizotrypanum cruzi. In the spleen, 

 bone marrow, and axillary glands round, ring, and coiled forms 

 were found on the fourth to sixth day, usually surrounded by 

 a clear area which gave the impression that the protoplasmic 

 mass was lying in a vacuoloid space that was surrounded by a 

 limiting membrane. In these forms the blepharoplast frequently 

 appeared to lie detached from the protoplasmic mass in the 

 clear area. Buchanan also found in smears of the spleen ring- 

 form parasites and all stages in the development of these to the 

 fairly mature trypanosomes within the red blood-corpuscles, 

 which appear to be similar to the intracorpuscular stages of 

 Schizotrypanum cruzi described by Chagas. 



In the development of Trypanosoma evansi in guinea pigs, 

 round nonflagellated forms are found in the spleen and bone 

 marrow that correspond to the "latent bodies" described by 

 Salvin-Moore and Breinl in Trypanosoma gamhiense and by 

 Fantham in Trypanosoyna gamhiense and Trypanosoma rliode- 

 siense. These bodies of Trypanosoma evansi, however, appear 

 to be not "latent," but developmental, forms which undergo 

 a schizogony comparable to that taking place in Schizotrypanum 

 cruzi. While all of the relations of this reproductive process 

 to the life-cycle of the parasite have not been worked out, nor 

 the process studied in the natural host of this trypanosome, it 

 has seemed advisable to publish a preliminary account of it. 

 The hope is expressed that it may lead to a more careful study 

 of what appears to be early stages of the same reproductive 

 process in Trypanosoma gamhiense and other species of Trypano- 

 soma, and to a further investigation of the relation, if any, 

 of the different stages of this process to latency in trypanoso- 

 miasis and to relapses after chemotherapeutic treatment. 



Two strains of Trypanosoma evansi, one from a horse and 

 the other from a carabao, have been studied. These two strains 

 have been propagated by subcutaneous inoculations from guinea 

 pig to guinea pig, and the development herein described is based 

 upon the study of the blood and organs of these animals. 



The blood, taken from the ear veins, and the internal organs 

 of guinea pigs killed at different periods of the infection, have 

 been studied fresh, in dried smears, in smears fixed wet, and 



