140 MICROBES, FERMENTS, AND MOULDS. 



the disease, but generally in a very mild form, and it 

 is an important result of this treatment that they are 

 henceforward safe from a fresh attack of the disease ; 

 in a word, they are vaccinated against anthrax. 



In the cultures prepared with the view of attenu- 

 ating the microbe, it is the action of the oxygen of 

 the air which renders the bacteridium less virulent. 

 It should be subjected to a temperature of from 42 

 to 43 in the case of Bacillus anthracis, to enable it 

 to multiply, and at the same time to check the pro- 

 duction of spores which might make the liquid too 

 powerful. At the end of the week, the culture, which 

 at first killed the whole of ten sheep, killed only four 

 or five out of ten. In ten or twelve days it ceased 

 to kill any ; the disease was perfectly mild, as in the 

 case of the human vaccinia, of which we shall speak 

 presently. After the bacteridia have been attenuated, 

 they can be cultivated in the lower temperature of 

 from 30 to 35, and only produce spores of the same 

 attenuated strength as the filaments which form them 

 (Chamberland). 



The vaccine thus obtained in Pasteur's laboratory 

 is now distributed throughout the world, and has 

 already saved numerous flocks from almost certain 

 destruction. Although this process has only been 

 known for a few years, its results are such that the 

 gain to agriculture already amounts to many thousands 

 of pounds. 



Toussaint makes use of a slightly different mode 



