﻿90 MIYAJIMA. 



of the calves, after the injection, was microscopically and culturally ex- 

 amined from time to time. One of the animals proved itself to be 

 refractive, as is observed in the case of the direct inoculation of the 

 infected blood. However, the others were infected with parasites, which 

 fact was first proved by the cultural method and later demonstrated to 

 be the case microscopically. In one instance, eight days after inocula- 

 tion, the blood of the susceptible animal began to give a growth of the 

 flagellated parasite in culture, whereas seventeen days later by the aid of 

 the microscope alone, the intracellular parasites were visible in the same 

 animal. (PI. Ill, fig. 12.) The number of our experiments on animals 

 is not as yet sufficiently large for us definitely to give the duration of 

 incubation of the infection and other details. 



The foregoing discussion brings us to the following conclusions : 



1. A variety of hamocytozoa known as Piroplasma parvum can readily 

 be cultivated outside of the living body. 



2. The parasites undergo the developmental change in blood-bouillon 

 and finally take the form of a typical trypanosoma. This trj^panosoma 

 can not be detected in the blood of infected animals. 



3. A simple mixture of blood and bouillon is the most suitable medium 

 for the cultivation of protozoa such as Piroplasma parvum and Trypan- 

 osoma lewisi. 



