SURRA 377 
hemorrhages, particularly on the right side of the heart and over the 
lower portion of the lungs. The lymphatics are in general somewhat 
enlarged, often markedly so. The heart muscle shows parenchyma- 
tous changes, in degree depending somewhat on the duration of the 
disease. 
In some of the lower animals the scrotum and even the testicles in 
the male and the vulva in the female are greatly swollen, and in the 
male rabbit the tension may be so great as to rupture the scrotum. 
Small preputial or labial ulcers are not uncommon. 
Steel noticed ulceration of the stomach in about two-thirds of his 
Fic. 88. PHOTOGRAPH OF BLOOD OF HORSE CONTAINING TRYPANOSOMA. 
(Taken by Smith and Kinyoun.) 
cases among mules in Burma. In India this ulceration has not been 
observed among horses asa sequence of surra. In the Philippines, 
changes in the intestine due to anemia with occasional ulcers are 
reported. 
The clinical aspect of surra is essentially one of progressive anemia, 
accompanied by paroxysms and intermissions, during both of which 
there is a natural decrease in the number of the red blood corpuscles 
and in the amount of hemoglobin in the blood, with consequent 
anemia of the visible mucous membranes. 
Smith and Kinyoun found the blood changes to be as follows: 
“The pathological changes caused by this parasite is a rapid destruction of the red 
blood cells,causing an acute anemia. The changes occur in the blood coincident with the 
