254 
Cultivation of Piroplasma 
which had shown “ marked multiplication ” at the bottom of tubes con¬ 
taining blood. After 15 days, according to Lignieres, the parasites in 
haemoglobin serum showed marked multiplication and a third subculture 
gave even better results than did the second. All the culture forms 
were spherical and he states they contained one to four germs which 
leave the parent cell, grow rapidly and often remain in pairs connected 
by a filament which cannot be demonstrated by staining. Lignieres 
(1903, PI. IV) illustrates such forms in a later publication but his de¬ 
ductions appear to be so largely hypothetical that we do not deem it 
necessary to consider them further. 
Dschunkowsky and Lulls (1901) tried to cultivate the parasites in 
haemoglobin serum in test tubes. A grayish deposit, which could be 
shaken up, formed at the bottom of the tubes. They thought they 
observed evidence of great multiplication at the end of 10—20 days. 
The parasites also appeared to multiply in defibrinated blood both inside 
and outside the red blood corpuscles. The parasites were definitely 
motile and appeared to multiply up to 20—25 days both at room 
temperature and at 38° C. (It was supposed at the time that they 
were working with Tlieileria parva.) 
Piroplasma ovis. 
Motas (1904, p. 31) attempted to cultivate this parasite in blood, 
blood serum and haemoglobin serum at different temperatures. His 
results were all negative. He notes that the blood gradually loses its 
virulence when preserved at 15—18° C., but may remain virulent up 
to 10—14 days. The blood remains virulent for longer periods, up to 
15—20 days, if maintained at lower temperatures, provided no bacterial 
growth takes place. If the tubes become contaminated virulence is 
only retained up to 5—10 days. The parasites did not live nearly so 
long when citrate or oxalate of potash were added to the blood. The 
virulence was not affected by an exposure of 12 hours to minus 5—6° C. 
or by exposure to 43—44° C. for the same time. 
Piroplasma eqni. 
Theiler (1903, p. 99) states chat he has on several occasions kept the 
blood of horses containing this parasite in vitro. The blood was placed 
in test tubes and kept at different temperatures, in the ice box, at room 
temperature, and in the incubator. In the incubator the parasites 
disappeared from the blood as soon as the corpuscles lost their 
