192 SOME MINUTE ANIMAL PARASITES 



shaped blepharoplast. Longitudinal division occurs, 

 just as in the insect flagellate. In fact, there is now 

 good evidence that the so-called Leishman- Donovan 

 body, orLeishmaniadonovani, is a developmental form 

 or resting stage of a herpetomonad which may occur 



in the bed bug of 

 India, Cimex rotun- 

 d at us . When 

 attempts have been 

 made to " grow " 



Kala-azar parasites 

 artificially in test- 

 tubes, it has been 

 a matter of some 

 difficulty to induce 

 development. But 

 citrated splenic 

 blood containing 

 parasites, when 

 kept at 22 to 

 25 C., showed 



D 



FIG. 38 THE PARASITE OF KALA-AZAR 

 IN TiiE BLOOD 



A , Mononuclear cell, containing twelve 

 Leishman - Donovan bodies ; B, C, 

 D, three parasites free in the blood- 

 stream 



active flagellates 

 swimming therein, 

 and the stages in 

 the development 

 f r o m a small, 

 motionless oval 



body to an active, elongate form with a lashing flagel- 

 lum, could be followed. However, it may be a long 

 way between what happens to an organism in a test- 

 tube and what occurs in Nature, where conditions 

 are more variable and less easily controlled. Conse- 



