260 THE LIFE OF PASTEUR 



hold broth, or beer-yeast water, either of them neutralized by 

 potash. After a few hours, a sort of flake was floating in the 

 liquid; the bacteridia could be seen, not under the shape of 

 short broken rods, but with the appearance of filaments, 

 tangled like a skein ; the culture medium being highly favour- 

 able, they were rapidly growing longer. A drop of that liquid, 

 abstracted from the first vessel , was sown into a second vessel , 

 of which one drop was again placed into a third, and so on, 

 until the fortieth flask ; the seed of each successive culture came 

 from a tiny drop of the preceding one. If a drop from one of 

 those flasks was introduced under the skin of a rabbit or 

 guinea-pig, splenic fever and death immediately ensued, with 

 the same symptoms and characteristics as if the original drop 

 of blood had been inoculated. In the presence of the results 

 from those successive cultures, what became of the hypothesis 

 of an inanimate substance contained in the first drop of blood? 

 It was now diluted in a proportion impossible to imagine. It 

 would therefore be absurd, thought Pasteur, to imagine that 

 the last virulence owed its power to a virulent agent existing 

 in the original drop of blood ; it was to the bacteridium , multi- 

 plied in each culture, and to the bacteridium alone, that this 

 power was due ; the life of the bacteridium had made the 

 virulence. "Anthrax is therefore," Pasteur declared, "the 

 disease of the bacteridium, as trichinosis is the disease of the 

 trichina, as itch is the disease of its special acarus, with this 

 circumstance, however, that, in anthrax, the parasite can only 

 be seen through a microscope, and very much enlarged." After 

 the bacteridium had presented those long filaments, within a 

 few hours, two days at the most, another spectacle followed ; 

 amidst those filaments, appeared the oval shapes, the germs, 

 spores or seeds, pointed out by Dr. Koch. Those spores, sown 

 in broth, reproduced in their turn the little packets of tangled 

 filaments, the bacteridia. Pasteur reported that "one single 

 germ of bacteridium in the drop which is sown multiplies 

 during the following hours and ends by filling the whole liquid 

 with such a thickness of bacteridia that, to the naked eye, it 

 seems that carded cotton has been mixed with the broth." 



M. Chamberland, a pupil who became intimately associated 

 with this work on anthrax, has defined as follows what Pasteur 

 had now achieved : " By his admirable process of culture out- 

 side organism, Pasteur shows that the rods which exist in the 

 blood, and for which he has preserved the name of bacteridia 



