228 PARASITOLOGY. 
tions which indicates the formation of anti-bodies 
against these organisms. As an example :—the piro- 
plasmosis caused by the piroplasma bigeminum. 
Sarcosporida.—The body of this protozoon con- 
tains a toxic substance. A small quantity of the 
aqueous extract has proved fatal to rabbits. Its 
toxic property is impaired when heat at 56° C. is 
applied for two hours, and is destroyed when sub- 
jected to a temperature of 85° C. for 20 minutes. 
The fact that it has been found that somg, of the pro- 
tozoa are affected by changes in osmoticyptessure in- 
dicates that their outer covering is permedfte or semi- 
permeable. ~ 
Nematodes.—The intestinal parasites ' without a 
doubt give off an active antitrypsin which enables 
them to live in the intestinal tract. It is also be- 
lieved by some investigators that they give off a toxic 
substance which 1s absorbed from the intestinal tract 
and produces the constitutional disturbance noted, 
when in large numbers. 
The fluid from these worms have proven toxic for 
guinea pigs. The intoxication and febrile state noted 
in infestation with Trichina Spiralis indicates a toxic 
substance. 
Cestodes—The fluid in tape worm cysts as the 
Cysticercus Echinococcus, Cysticercus Tenuicollis, 
Cysticercus Pisiformis, Cysticercus Cerebralis and 
the Cysticercus Serialis have been found to be highly 
toxic. The symptoms this fluid produces are local 
irritation, inflammation and urticaria. No toxic 
symptoms are noted till the cyst wall is ruptured and 
the liberated fluid absorbed. These cysts contain a 
