296 H. M. WOODCOCK. 



there is no otiier host among the Primates it is improbable that there is 

 any other Mammalian one for this species. The Invertebrate host is, 

 undoubtedly, Glossina palpalis; the possibility of this being so appears 

 to have been first suggested by Brumpt (9). The distribution of this 

 Tsetse-fly narrowly coincides with that of the disease, and where there is no 

 fly, sleeping-sickness is not prevalent. It has not yet been proved whether 

 or no other species of Glossina also naturally transmit the parasites. 



Nabarro and Grieg (S. S. Rep., No. 5) mention, in addition, the occur- 

 rence of three or four cases of trypanosomosis among diseased animals 

 which came under their observation in Uganda. The parasites occurred as 

 follows : — (a) in sick transport oxen in Entebbe, which came originally from 

 East Africa (the illness caused being locally known as " Mukebi ") ; (b) in a 

 herd of diseased cattle at Jinga, Busoga ("Sutoko"); (c) in an English 

 dog which had contracted the disease while with the Abyssinian Boundary 

 Commission ; and (d) in a sick mule at Entebbe. Prom the observations 

 and animal experiments by these workers, and subsequently by Grieg and 

 Gray (24 b), the conclusions arrived at are as follows : — the Trypanosomes 

 concerned are probably all distinct from T. garabiense; (a) the parasite 

 in sick oxen at Entebbe (" Mukebi") is a distinct species; (h) the "Jinga" 

 Trypanosome is most probably a variety of T. brucii, the illness being an 

 acute form of Nagana; (c) and (d) the "Abyssinian Boundary" parasites 

 and the Trypanosomes found in a sick mule appear to be identical, and con- 

 stitute probably another distinct species. 



T. dimorpbon, Dutt. and Todd, 1904. As implied by the specific name, 

 more than one "type" of this parasite is usually distinguished. One is 

 small and tadpole-like (fig. 49, I b, II a), the other long, fusiform, and more 

 resembling an ordinary Trypanosome (I a, II d). A third variety, wide 

 and stumpy (II b and c) is also distinguished by Button and Todd, but 

 Laveran and Mesnil (54) consider that this only represents an enlarged 

 tadpole form about to divide. The average dimensions are : of the tadpole 

 variety, length 10-15/* by •7-l'5At; of the elongated one, length about 

 25)1* by 1^-2 A*. The exact relations of these two kinds of form to one 

 another have not yet been ascertained. Although Laveran and Mesnil 

 describe and figure a series of intermediate stages (I), they do not think 

 that the smaller type grows or passes into the longer one, basing this view 

 on the ground that each is capable of reproducing its like by equal binary 

 fission.' In one important respect the accounts of Laveran and Mesnil and 

 of Dutton and Todd are at variance. The first-named authors maintain 

 that none of the parasites have any free continuation of the fiagellum, this 

 terminating, in all cases, at the posterior end of the body, which is here 



' It is quite possible, however, that these large parasites possess some 

 other mode of division in addition, by means of which they give rise to a 

 fresh succession of tadpole forms. 



