THE TRYPANOSOMES OF MAN 



419 



times from T. brucei, but its altered environment in man has 

 changed its physiological characters. As the fly remains the same, 

 one would expect this portion of the life-cycle to be similar in the 

 two trypanosomes. 



We look upon T. nigeriense and T. gamhiense var. longum as 

 belonging to T. gamhiense, because, apart from the morphological 

 similarity, to which We do not assign importance, their pathological 

 action in man and the lower animals appears to be identical. 



As a result of these considerations, and changing the names so as 

 to agree with the new nomenclature, we recognize the following 

 parasites of man : — ■ 



A. Belonging to the genus Castellanella : — ■ 



1. Castellanella gambiensis (Dutton, 1902). 



2. Castellanella casfellanii (Kruse, 1903). 



3. Castellanella rhodesiensis (Stephens and Fantham, 1910). 



B. Belonging to the genus Duttonella :■ — ■ 



.4. Duttonella vivax (Ziemann, 1905), var. Macfiensis 

 (Castellani and Chalmers, 1918). 



C. Belonging to the genus Schizotrypanum : — ■ 



5. Schizotrypanum cruzi Chagas, 1909. 



These five species may be differentiated as follows : — ■ 



A. With schizogony — 5. cruzi. 



B. Without schizogony: — 



1. Monomorphic — D. vivax. 

 II. Polymorphic : — 



{a) Posteriorly nucleate — C. rhodesiensis. 

 (b) Not posteriorly nucleate : — • 



1. Animal infections chronic and comparatively 



mild. Common North-West Africa — • 

 C. gambiensis. 



2. Animal infections severe. Common Equatorial 



Africa — C. castellanii. 



Castellanella gambiensis (Dutton, 1902). 



Usual old name Trypanosoma gambiense Dutton, 1902. 



Synonyms. — T. nepveui Sambon, 1903; T. hominis Manson, 1903; 

 T. fordii Maxwell, 1903 ; T. nigeriense Macfie, 1913 ; T. gambiense 

 var. longum Da Costa, St. Anna, Dos Santos, and Alvares, 1915. 



Definition. — Castellanella without schizogony, polymorphic, tro- 

 phonucleus not situate close to aflagellar end. Infections chronic. 



History. — This trypanosome was flrst noticed by Ford in a case 

 of peculiar fever on the Gambia. He showed the parasite to Dutton, 

 who, recognizing it to be a trypanosome, described and named it; 

 and they considered it to be the cause of Gambia fever, which was 

 never thought by them to be connected with sleeping sickness. 

 The organism had, however, been previously seen in the blood of 

 man and imperfectly described by Nepveu. We consider it to be 



