250 
Cultivation of Piroplasma 
Dog VIII. In this case all the cultures were kept at 24° C. In 
O’6°/ 0 salt solution after 18 hours large forms were numerous, some of 
which had radiating processes. 
Examinations made after 32 and 48 hours’ cultivation showed many 
large forms, a few of which possessed well marked radii. 
In 0'8 °/ 0 salt solution and in “ P ” solution large forms were seen, 
but none with true radii. 
Dog IX. Cultures were made in 0 - 8°/ 0 salt solution and were kept 
at 24° C. After 30 hours many large pyriform bodies were seen, a few 
of which showed radiating processes, but after 44 hours both the large 
forms and those with radii were less numerous. Similar cultures in 
0’6°/ 0 salt solution and in “P” solution showed no forms with radiating 
processes. 
Dogs X, XI, XII, and XIII. Similar experiments were made with 
blood derived from these animals, but no forms with radii were seen. 
Dog XIV. Cultures made in 0'8°/„ salt solution and kept at 24° C. 
for 26 hours showed numerous forms with well marked radii. Motility 
was observed in some of them. 
Dogs XV, XVI, XVII, X VIII, and XIX. Similar experiments 
were made with the blood of these animals but no forms with true radii 
were seen. 
From the foregoing account it can be seen that in some experiments 
numerous forms with radiating processes were encountered, whilst in 
others, apparently conducted under exactly similar conditions, none 
were found. We have been entirely unable to find any cause for these 
differences in the behaviour of the cultures. 
The differences apparently do not depend on the age of the animal 
from which the blood was taken, the height of the fever, or the rapidity 
with which it developed. Nor do they appear to depend on whether 
the temperature was falling or stationary, or on the period at which the 
blood was taken either in regard to the date of inoculation, or to the 
time at which the fever appeared. The following table summarises the 
data on which these statements are based. 
The forms with radiating processes were found most commonly in 
cultures made in 0'6 °/ 0 salt solution, and were most frequently obtained 
from the uppermost part of the layer of blood corpuscles. Although it 
appears to be necessary to use small quantities of fluid, probably in 
order to ensure the presence of a sufficient oxygen supply, we did not 
find that better results were obtained in shallow tilted dishes, with 
extremely shallow layers of fluid. Cultures which were left absolutely 
