PROTOZOA AND DISEASE. 121 
called Leishman-Donovan body, the parasite of dum-dum 
fever or splenomegaly, a disease occurring in India and 
Africa, has recently been shown to be a stage in the 
life history of a flagellate protozoon. Of great import- 
‘ance, also, is the family of Spirochztes, one of which, 
Treponema (Spirochete) pallidum, is the organism which 
causes syphilis. Another highly important genus is Fivo- 
plasma (Babesia), a sporozoon. These are blood parasites, 
Fic. 54. 
2. Trypanosoma gambiense, showing nucleus, blepharoplast, 
and flagellum. 
2and 3. Individuals undergoing longitudinal fission. 
4. Leucocyte engulfing a trypanosome. 
causing Texas fever in cattle and analogous diseases in 
horse, sheep, dog, and possibly man also. The parasite 
of Texas fever is transmitted through two generations 
of ticks. Lastly may be mentioned the parasites of 
‘malaria, JLaverania and Plasmodium, whose compli- 
‘cated life histories in mosquito and man are now well 
‘known. j , 
General zoological interest.—The Protozoa illustrate, in 
