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 Infested, — Horse, camel, elephant and 

 dog. 



Paris Infested.— The blood. 



Disease Produced — Surra : rot. 



Fig. 73— Trypanosoma Evansi 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 o£ the mucous membrane of the eyes and 



