196 SOME MINUTE ANIMAL PARASITES 



insects able to transmit the disease when allowed to 

 bite healthy animals. The parasites merely degener- 

 ated in the insects employed. 



Attention was given at the same time to the bed- 

 bugs which were so extremely common. By a series 

 of careful experiments, Captain Patton proved that 



FIG. 39 THE PARASITE OF KALA-AZAR IN THE BUG 



A-D, Show the gradual development of the flagellum ; E, very 



young flagellate ; F-H, division stages ; K, full-grown flagellate 



the Kala-azar parasites actually underwent develop- 

 ment in the Indian bed-bug, Cimex rotundatus. Once 

 the parasites had been absorbed by the bug, the leuco- 

 cytes and cells containing them (Fig. 38, ^4) began 

 to degenerate, and the small parasites were set free 

 (Fig. 39, A). Some began to elongate almost at 



