ANTHRAX 121 



man ; and anthrax is produced by a bacterium known 

 as Bacillus anthracis, which had been recognized and 

 was accused of causing the disease before Pasteur began 

 to interest himself in such matters. It annually carried 

 off 20 per cent, of the sheep in the agricultural district 

 of La Beauce, and in Auvergne some 10 to 15 per cent. 

 In certain localities the loss was greater, amounting 

 at times to an annual death-rate of 50 per cent. The 

 disease was by no means confined to France ; it was 

 spread over Europe. In the government of Novgorod 

 it was responsible for over 56,000 deaths in three 

 years. In Egypt it was regarded as the direct 

 descendant of the plagues of Pharaoh. It ravaged the 

 large sheep farms of the Argentine Republic. 



The bacillus which causes this disease, and which at 

 times by inhalation effects a lodgment in the bodies of 

 those engaged in handling wool and hides, was already 

 known when Pasteur took up the study of pathogenic 

 germs. About the same time it was also attracting 

 the attention of the young German physician Dr. 

 Koch, who subsequently became a severe critic of 

 some of Pasteur's work; but in this article we are 

 dealing with Pasteur, and limitations of space compel 

 us to leave unnoticed the brilliant work of many in- 

 vestigators who have made the latter end of the nine- 

 teenth century one of the greatest epochs in medical 

 history. 



Pasteur and his assistants made many fascinating 

 studies on the behaviour and life-history of the 

 Bacillus anthracis. He found it very susceptible to 

 slight variations of temperature. The few degrees by 

 which the temperature of a bird's blood exceeds that 

 of a mammal were sufficient to prove fatal to the 

 bacillus ; but by an ingenious experiment he showed 

 that if the temperature of a bird be artificially lowered 

 it becomes susceptible to the disease, though it readily 

 recovers if the artificial surroundings be removed. 



