198 PARASITOLOGY. 
plasm divide into two. The newly formed Trypano- 
somes develop to full sized organisms and divide 
again. An insect,—as a blood sucking fly—feasting 
upon an animal affected with surra, becomes infested 
and in turn by piercing the skin of another animal 
to draw blood, inoculates it. 
Animals Intested.—Horse, camel, elephant and 
dog. 
Parts Intested.—The blood. 
Disease Produced—Surra; rot, 
Fig. 73—TRyPANOSOMA EvaANsi and blood cells. 
Symptoms.—The Trypanosoma invades the blood 
stream and develops very rapidly; if they be im- 
mediately introduced into the blood stream they 
cause the first symptoms of surra to appear in from 
six to eight days. Surra is marked by a thermic 
disturbance; there is noticed a remittent or inter- 
mittent fever which lasts for several weeks; erup- 
tions, resembling those of urticaria, may appear; 
petechia of the mucous membrane of the eyes and 
> a 
