1922] on Microscopic Parasites and their Carriers 517 



Fig. 8. — Piroplasma (Babesia canis) of the Dog, and its transmission by 

 the dog tick (Bhipicephalus sanguinceiis). 



a-d Parasites in the red blood corpuscles of the dog. (Magnified 2000 times.) 

 a-b, two forms of the parasite, the round and the amoeboid form; c-d, multi- 

 plication in the blood by division of the parasite into two. 



h, o, p, s Diagram of the tick to show the very much branched stomach, h ; 

 the salivary gland, s ; the proboscis, p ; and the ovary, o. 



e Egg of tick, which contains the parasite. 



l Larva of tick, which is infected when it hatches from the egg. 



x-z Development of the parasite in the tick. (Magnified 3000 times.) 

 X, elongate form which grows in the tissues of the tick, and finally produces a 

 large number of minute parasites, z, which invade the ovaries and infect 

 the eggs. 



