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quantity of broth. When, after a few days, the contents of 

 the larger flask appears quite turbid, the cultivation of 

 the bacilli is finished, and the vaccine can be used for inocu- 

 lating animals to protect them from anthrax, two drops for 

 sheep and four drops for cattle. 



1.347. This method of attenuation is exactly opposite 

 to that of Pasteur in this respect, that in Pasteur's method 

 spore formation is suppressed, whereas in Chauveau's method 

 spore formation goes on profusely inside the oxygen 

 vessel. 



1.348. Pasteur's method of preparing anthrax vaccine 

 consists in keeping the virulent vaccine for 20 days at a 

 uniform temperature of 42 to 43 C. in the preparation of the 

 weaker or premier vaccine ; and at the same temperature for 

 12 days in the preparation of the stronger or deuxieme 

 vaccine. 



1.349. It may be here remarked in passing, that the 

 periods of time, or the degrees of temperature mentioned 

 throughout this Chapter, need not be so exact. If, for instance, 

 instead of keeping the virulent vaccine for 12 days in the 

 etuve at 41, 42, 43, or even 44 C., one were to keep it 

 for 15 days under the same conditions, the character of the 

 vaccine will not be much different. The figures used are 

 the most favourable. But if an accidental departure to a 

 small extent takes place, it does not do any harm. They are 

 not exact to a degree and a day or an hour, as the case may 

 be, in either Pasteur's laboratory or in the laboratory at 

 Lyons. When, however, the time prescribed is three hours, 

 it will not do to have it only one hour or one day. In this 

 case a difference of a few minutes is of no consequence. 



1.350. In M. Pasteur's laboratory the preparation of 

 the vaccines is not taught. The above description was com- 

 piled by the author at the Veterinary College laboratory at 

 Lyons and also at Professor Duclaux's Laboratory in Paris. 

 What is taught in Pasteur's laboratory is how to manage the 



