THE BACTERIDIUM IS THE SOLE CAUSE OF ANTHRAX 251 



la biere, and his contests with his opponents, he came 

 out well equipped, with a perfected technique, and a 

 knowledge both of bacterial species and of how to grow 

 them. To solve all these problems he could draw only 

 from his own depths, and this he showed at once. 



Old observations and experiments had taught him 

 that the blood of a sound animal, taken as it circulates 

 in the veins and exposed to air which is free from germs, 

 does not putrefy at the highest temperatures, nor give 

 birth to any organism. It seemed to him probable, 

 therefore, for he knew nothing then of the cultural ex- 

 periments of Delafond and of Koch, that the blood of 

 an animal infected with anthrax, if sown in a suitable 

 medium, would stock it solely with anthrax bacilli which 

 he could then keep pure for an indefinite time in suc- 

 cessive cultures, as he had done with yeast and other 

 ferments. 



Experiment proved it to be so, and showed that this 

 bacteridium multiplies abundantly in urine made neu- 

 tral or slightly alkaline. From that time, the problem 

 was solved. Let us take a series of cultures of this 

 bacteridium transferring each time one drop from the 

 preceding culture into 50 cc. of fresh urine. The first 

 dilution is 1/1000, the second 1/1,000,000, the third 

 1/1,000,000,000, etc. After ten cultures it falls to 

 such a figure that the original drop of blood which 

 furnished the first sowing, has been, so to speak, drowned 

 in an ocean. Everything that it carried with it, to 

 which we might be tempted to attribute a role in the 

 production of anthrax red corpuscles, white corpuscles, 

 granules of all sorts are either destroyed by the change of 

 medium or are widely disseminated in this ocean and are 

 lost there. Only the bacteridium has escaped the dilution 

 because it has multiplied in each of the cultures. 

 But a drop from the last culture kills a rabbit or guinea 



