THE TRANSMISSION OF LFISII MANIOMS BY CULTURES. 381 
agar according lo Novy-Xicolle of blood taken aseptically 
from the lieart, spleen, liver, bone-marrow, and in some cases 
of the peritoneal fluid. The results were constantly negative 
except with the peritoneal fluid a short time after the injec- 
tion of the culture, when it is still possible to find by micro- 
scopic examination some Leishmanias living and mobile. 
Thus after an hour and a quarter in one rat I was able to 
obtain a new culture from the peritoneum, while after two 
hours the result has always been negative. 
In complete accord with the result of the histological 
examination I have never obtained development of flagel- 
lates in a culture from the blood or from the internal organs, 
not even by injecting into the peritoneal cavity or directly 
into the circulation 4 c.c. of cultural fluid very rich in Leish- 
manias. These flagellate Protozoa would not, therefore, pass 
beyond the peritoneal barrier in the guinea-pig and the rat. 
I have stated above that I have injected the cultures of 
Leishmania directly into the blood in some animals. Al- 
though my investigations may not be sufficiently numerous, 
being limited to one guinea-pig and one rat alone, I have 
noted in the blood immediately after the injection a marked 
leucocytosis with prevalence of mononuclears, which reached 
its maximum degree after five to ten minutes, was maintained 
for half an hour, and then diminished gradually. In these 
cases also I was never able, even soon after the injection, to 
find flagellate Leishmanias in the blood, nor have I seen 
phagocyted forms. The animal has not contracted any 
infection. 
SUMJIAKY. 
Guinea-pigs and rats possess natural immunity to a high 
degree against the Leishmania of the Mediterranean basin in 
the flagellate stage in cultures on blood-agar (method of 
Xovy-.McNeal-Xicolle) . 
This immunity is exclusively of phagocytic nature. The 
I’rotozoa injected into the peritoneum become rapidly en- 
