486 



ZOOLOGY 



Anthrax 



The 



vaccination 

 of sheep 



12. In 1877 Pasteur undertook to combat the 

 anthrax or charbon disease, which was killing great 

 numbers of cattle and sheep. There were places where 

 half the sheep in a flock perished. Even human beings 

 were occasionally attacked. No one knew what to do. 

 The disease was due to a relatively large bacillus, very 

 difficult to destroy. This organism was isolated and 

 described by Dr. Koch of Germany. Pasteur de- 

 veloped a method of vaccination, following the general 

 plan employed for smallpox. It is not necessary here 

 to describe his methods of preparing the "attenuated 

 virus," which he injected into the animals to be pro- 

 tected. The theory of vaccination is based on the fact 

 that the body is able to develop substances which com- 

 bat or neutralize the poison, and that if it is warned by 

 a weak dose, it will be ready to withstand a strong one. 

 The function of vaccination, then, is not unlike that of 

 the Scotch thistles or the geese at Rome, famous in his- 

 tory. The notion of vaccinating sheep did not com- 

 mend itself to the veterinarians, and, as in the case of 

 the silkworm disease, Pasteur sought a public demon- 

 stration. The Melun Agricultural Society put sixty 

 sheep at his disposal. Twenty-five were to be vacci- 

 nated twice, and later inoculated with virulent anthrax. 

 Twenty-five others were to be inoculated without vacci- 

 nation. Ten, untreated, remained to show that the 

 flock was normal. Now, said Pasteur, the unvacci- 

 nated sheep, on being inoculated, will perish. The 

 vaccinated ones, also inoculated, will remain healthy. 

 After anxious days, during which even Pasteur feared 

 that something would go wrong, the experiment proved 

 successful, and the whole population joined in applause. 

 Once more an important industry had been saved from 

 destruction. 



