Immunity 545 



inoculated with such attenuated cultures, no other change 

 occurs than a local inflammatory reaction that soon disap- 

 pears and leaves the birds protected against future infec- 

 tion with virulent bacilli. From these observations Pasteur 

 worked out a system of protective vaccination in which the 

 fowls are first inoculated with attenuated, then with more 

 active, and finally with virulent cultures, with resulting 

 protection and immunity. 



Use has been made of this bacillus to kill rabbits in Aus- 

 tralia, where they are pests. It is estimated that two gallons 

 of bouillon culture will destroy 20,000 rabbits irrespective 

 of infection by contagion. 



The bacillus of chicken-cholera may be identical with 

 organisms found in various epidemic diseases of larger 

 animals, and, indeed, no little confusion has arisen from 

 the description of what is now pretty generally accepted to 

 be the same organism as the bacillus of rabbit-septicemia 

 (Koch), Bacillus cuniculicida (Flugge), bacillus of swine- 

 plague (Loftier and Schiitz), bacillus of "Wildseuche " 

 (Hiippe), bacillus of " Biirlelseuche " (Oriste-Armanni), etc. 



35 



