36o 



1. T. lewist. — Is found in a small percentage 

 of ordinary sewer rats in England. It ,is non- 

 pathogenic. It is common in rats of tropical 

 countries. White rats are easily infected, but 

 never spontaneously show infection. Possibly 

 there are various species of this trypanosome. It 

 is slenderer than T. brucet. Its undulating" mem- 

 brane is less wide. It is stated that infection can 

 be transmitted by a rat flea. 



2. T. brucei. — This is the highly pathogenic 

 trypanosome of Ngana, or tsetse fly disease. 

 Lengthj27 m by 2 m- T. brucei is fatal to nearly 

 all, if^not all, mammals. In the horse there occurs 

 watery discharge from the eyes and nose ; puffy 

 swelling under the belly ; sheath of penis, etc., 

 marked anaemia, wasting. 



Fig. 81. T. gambiense, T.leivisi, T. brucei, T. equiperdum, 



and dividifig form of T. brucei, shewing two nuclei, 



two blepharoplasts 



The disease was shown by Bruce to be con- 

 veyed from infected animals to healthy ones by 

 means of Glossina morsttans. The fly after biting 

 remains infective from twelve to forty-eight hours. 



