126 INFECTIOUS DISEASES DUE TO PROTOZOA 



marrow, etc. The parasites are smaller in the corpuscles contain- 

 ing many. Free parasites are also found, especially in advanced 

 stages of the disease (Robertson). Graham-Smith reports that 

 free forms are seldom seen in the earlier stages of the disease but 

 later become more numerous. On the day of death he found one 

 free parasite to 18 infected corpuscles. 



The number of infected corpuscles varies considerably. They 

 are more abundant in the acute form, in which they are in con- 

 siderable numbers during and immediately after the febrile period. 

 The following table shows the percentage of infected corpuscles 

 and the duration of the disease in 11 cases of the acute and sub- 

 acute forms of the disease (from Graham-Smith). 



Table XXXVII. — Canine Piroplasmosis (Graham-Smith). 



In dog I, the proportion of infected to non-infected corpuscles 

 varied from .3-.6% from the first appearance until the day before 

 death. In dog II, only .05% were infected five days before death, 

 two days later .3% were infected. 



In the chronic form the parasites are often scarce. Usually 

 examinations made on successive days will reveal their presence. 

 In some cases it is necessary to inoculate several c.c. of blood from 

 the suspected case into a young dog which will often develop an 

 acute case in which the parasites may easily be found. The 

 parasites are more numerous at autopsy in (he capillaries of the 

 internal organs. In the majority of cases Graham-Smith found 



