FERMENTS, FERMENTATIONS, AND LIFE. 271 
hindering the development of these organisms, and thus 
preventing the malady. 
When we inject into the subcutaneous cellular tissue of 
a living animal a putrefied or septic liquid, that is, one 
containing those thread-like corpuscles known by the name 
of vibrios and bacteria, it sometimes happens that the ani- 
mal experiences no inconvenience. Dogs particularly re- 
sist with vigor the poisonous influence of such a fluid, but 
the case is different with other species, and notably with 
rabbits. The system becomes the seat of grave phenomena, 
almost always mortal, of which the general group com- 
poses the affection known by the term septicemia. The 
microscopic organisms in such a case poison the animal, not 
only by the mere fact of their presence in the blood, but 
besides and especially because they develop and propagate 
in it with astonishing rapidity, in the same way that yeast 
reproduces itself in barley-wort. But the most singular 
thing in these pathological fermentations is the fact noted 
some years ago for the first time by Coze and Feltz, and 
the study of which Davaine took up last year. Davaine 
demonstrates, by experiments made on rabbits and Guinea- 
pigs, that one drop of blood, from an animal affected with 
septicemia, has the power of imparting the infection to 
another animal inoculated with it, that a drop taken from 
the second can transmit the disease to a third, and so on. 
Still more, very wonderfully, the poisoning power of the 
blood of these animals increases with the degree of advance 
in the series of inoculations. The culture of the virus 
heightens its maleficent properties. ‘This gradual increase 
of the virulent force is such that, if we take a drop of blood 
from an animal representing the twenty-fifth term in a 
series of successive inoculations, and so dilute this drop 
with water that a drop of the dilution corresponds to one 
trillionth of the original drop, we get a liquid of which the 
smallest quantity still displays mortal activity. These ex- 
