THE MICROBE OF PLEURO PNEUMONIA. 
237 
guinea pigs ; we have never succeeded ; even after leaving them 
six weeks in the peritoneal cavity, the bouillon remained as 
limpid as it was on the first day, no matter how great the quan¬ 
tity of virus it had received. 
It is, then, a special microbe, which has grown through suc¬ 
cessive cultures in the peculiar media created by osmotic ex¬ 
changes, in the rabbit, within a bag of collodion or of reed-cane. 
Is this peculiar microbe the agent of pleuro-pneiimonic viru- 
lency ? 
Inoculation allows an affirmative answer. 
We proved it by our observation of five cows in which inocu¬ 
lations of a small quantity of culture in bags has given rise to 
the appearance of the essentially characteristic pleuro-pneu- 
inonic swelling. 
One of those cows (No. i) has died with a tremendous 
oedematons infiltration ; the four others resisted. Two of them 
(Nos. 2 and 3) reinoculated in forbidden region with a large 
dose (i c.c.) of pulmonary serosity, have not shown the slightest 
local or general symptom, while a susceptible cow (No. 4) inocu¬ 
lated at the same time, as a witness^ with 10 drops of the same 
serosity, died twenty-two days after inoculation. A third cow 
(No. 5) reinoculated after four months with i c.c. of pulmonary 
serosity from a subacute lesion, has not yet presented any fever 
nor any local lesion. The fourth (No. 6) has not yet been rein¬ 
oculated. 
* 
* * 
As we remarked above, the culture taken out of a collodion 
bag, after a stay of 15 or 20 days in the peritoneum of a rabbit, 
no matter how rich it may be, does not give rise to any growth 
when reinoculated in vitro^ in the air or vacuum, in any of the 
solid or liquid medias ordinarily used in bacteriology. How¬ 
ever, cultures very nearly alike those of the bags can be obtained. 
But for that one must use sterile bouillon for liquid of cul¬ 
ture, not inoculated, and which for several weeks has been kept 
in collodion bags within the peritoneum of a cow or a rabbit. 
Though free from virulent germs, this bouillon is also modified 
