318 



THE PROTOZOA 



development in which slender, so-called " spirillar " forms are split 

 off from the large leptomonad forms. 



There can be little doubt but that the cultural development observed in 

 all the species of Leishmania represents the natural development which t he 

 parasite goes through in some invertebrate host. As regards, first, L. dono- 

 vani, arguments have been brought forward incriminating the bed-bug as the 



FiO. 140. Leishmania tropica. A, Parasites from the sore, showing different 

 forms ; B and C, development in cultures : B, parasites growing and multi- 

 plying prior to the formation of the flagellum ; C, adult flagellated leptomonad 

 forms, with a couple probably the result of binary fission ; D, adult leptomonad 

 form ; E, similar form with the kinetonucleus dividing ; F, G, stout forms, 

 two stages of division ; note the flagella arising direct from the kinetonuclei, 

 which are connected by a centrodesmose, indicating that the centriole is con- 

 tained within the kinetonucleus (compare p. 87). A C, after Row, from 

 preparations stained by the Romanowsky method, magnified 2,000 : D G, 

 after Wenyon (84), from preparations stained with iron-hsematoxylin after 

 wet fixation. 



transmitting agent, and Patton (573) has found that the parasite goes through 

 the same stages of development in the digestive tract of the bug (Cimex rotun- 

 datus) as in the artificial cultures ; but Donovan believes the true intermediate 

 host in Madras to be another species of bug, Conorhinus rubrifasciatus, and 

 Wenyon (84) considers that the development in the bug obtained by Patton 

 is, like the development in artificial cultures, only an imitation of the develop- 

 ment in the true host, and not a proof of transmission by the bug. Basile 



