high degree, and that this virulence was increased by successive inoculations. A similar series of investigations had led another French physician, Davaine, to the opinion that the disease called anthrax, when it occurs in animals, and malignant pustule when it affects man, was caused by a certain variety of bacteria, to which he gave the name bacteridia.

Davaine repeated the experiments of Coze and Feltz, and in September, 1872, read before the Académie des Sciences, in Paris, a report of three series of inoculations with putrid blood, the results of which were so startling that for several months the discussions in the Academy turned almost exclusively upon the subject of septicæmia, or blood-poisoning. The first series showed that inoculation of a rabbit with a drop of blood, putrefied in the open air, rarely killed the animal, and that sometimes ten or fifteen drops were necessary. The second series comprised successive inoculations of blood from one septicæmic animal to the next, and showed that ¹⁄₁₀ to ¹⁄₁₀₀ of a drop was sufficient to kill the fifth, ¹⁄₁₀₀₀₀ ¹⁄₂₀₀₀₀ would kill the tenth, while, for the twenty-fifth, the one-ten-trillionth part of a drop was fatal.

Incredible as some of these assertions seemed, they were verified by many experimenters; but the minimum dose that would certainly kill was placed at the one-millionth part of a drop. Davaine claimed that the active poisonous principle was the bacterium, which, by its growth and multiplication in the blood, acted as a ferment; and this opinion, supported by Pasteur, was generally accepted, and it was supposed that the ordinary acute inflammatory complications of wounds, accompanied by symptoms of general poisoning, were caused by the accidental entry of bacteria. The same opinion had been held before, and the novelty of Davaine's views lay chiefly in the excessive minuteness of the quantity necessary to produce the effect.

The chief benefit derived from these experiments and discussions in Paris was found in the great interest which was excited everywhere in the question. The experiments were repeated, and the conclusions examined in almost every pathological laboratory in Europe, and we have every reason to expect that, through this general examination and discussion, the truth will appear. From time to time articles appeared denying the virulence claimed for bacteria; the earliest of these was a paper submitted to the Académic des Sciences, in April, 1873, by M. Onimus, who had been experimenting under the direction of Prof. Robin. He placed putrefying blood in a bag made of a dialytic membrane, and immersed the whole in distilled water, which, after a few hours, was found to be filled with bacteria. Inoculation with the blood produced the usual results, but inoculation with the water caused no septic symptoms whatever; on the other hand, the same blood, when subjected to various processes which removed or destroyed the bacteria, retained its virulence, and from these ex-