INTRODUCTION. 



41 



Maintenance of Parasitic Protozoa in Laboratory Animals. — 

 In a laboratory strains of parasitic Protozoa may be main- 

 tained in suitable animals which have been found by previous 

 examination not to harbour natural parasites of their own. 

 This method serves the same purpose as cultivation, and it is 

 easier to maintain a strain in an animal host than in a culture. 

 Blood parasites, such as the malarial parasites and the piro- 

 plasmata, can be introduced by inoculating the blood from 

 an infected to a clean host, and parasites that pass out in the 



& 

 0--F 



>(f-E 



^^S\ 



-c 



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Fig. 2. — Sinton's apparatus for cultivation of malarial parasites in 

 a small quantity of blood. The smaU Wright's capsule 

 shown on the right contains the ascitic or hydrocoele fluid. 

 (After Sinton.) 



encysted condition, such as Coccidia, can be mixed with the 

 food and allowed to be ingested. The practice has been 

 particularly successful in certain special cases. 



The malarial parasites of birds can be maintained for a long 

 time in canaries, sparrows, and other susceptible birds by 

 inoculating blood from the one to the other. Some birds 

 acquire heavy and fatal infections and others mild ones from 

 which they recover. The piroplasmata of dogs are readily 



