BACTERIA AND THEIR EFFECTS. 403 



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 Sep- 

 tember, 1872, read before the Acadhnie 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 septicaemia, 

 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 

 septicemic animal to the next, and showed that -^ to yi-g- of a drop 

 was sufficient to kill the fifth, 10 ^ 00 to iii) l l)i) 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 sup- 

 posed 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 minute- 

 ness 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 every- 

 where in the question. The experiments were repeated, and the con- 

 clusions examined in almost every pathological laboratory in Europe, 

 and we have every reason to expect that, through this general exam- 

 ination 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 Acad'emie 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. Inocu- 

 lation 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- 



