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 septicaemia. 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 

 septicaemia, 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- 



