228 PARASITOLOGY. 



tions which indicates the formation of anti-bodies 

 against these organisms. As an example : — the piro- 

 plasmosis caused by the piroplasma bigeminiim. 



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 some of the pro- 

 tozoa are affected by changes in osmotic pressure in- 

 dicates that their outer covering is permeable 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 is 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 i^n tape worm cysts as the 

 Cysticercus Echinococcus, Cysticercus TenuicoUis, 

 Cyisti'cercus Pisiformis, Cysticercus Cerebrailis 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 



