576 The Blood Flagellates 



F G 



Fig. 12. 1. A-E. Flagellated forms of Leishmania donoi'njii from cul- 

 tures; x2500; (A, B after Laveran; C-E, after Wenyon). F-H. Leishmania 

 tropica, leishmanial forms from sores; x5500 (after Weuyon). I. L. donovani 

 in large mononuclear cell; from blood. xl350 (after Laveran). J. L. dono- 

 vani in spleen; semidiagrammatic. xlO.S5 (after Xattan-Larrier). K. L. dono- 

 vani in liver; semidiagrammatic, xl035 (after \attan-I.arrit-r). 



develops a flagellum, and becomes a leptomonad form (Fig. 12. 1, A-C) 

 measuring 7-20ij, in length. Active leptomonads are usually abundant in 

 cultures after 48-72 hours at 22-25°. Old cultures may contain non-flagel- 

 lated stages resembling the original leishmanial forms. 



The organism causing American cases of visceral leishmaniasis, found 

 in dogs and cats as well as in man, has been considered a new species, 

 L. chagasi (14). However, the flagellate may be identical with L. donovani 

 of kala-azar (2, 59). 



