Ccnitagious and Epizootic Diseases. 45 



other, so that their numbers are generally kept within benef- 

 icent bounds. In the case, however, of those that can live 

 in animal and vegetable bodies, the limit is manifestly set 

 by the number of such susceptible bodies furnished ready 

 to be attacked. Hence the danger of a plague is always 

 proportionate to the number of live-stock susceptible to it, 

 and with continual intercourse between these there can be 

 no limit to the rapid progress, the extent, and the deadly 

 effects of the infection. 



LIST OF DISEASE-PEODUCING BACIEEIA. 



The following is a partial list of the bacteria found in 

 diseased states in animals : 



Bacterium. Short Bods. 



Bacterium Syncyanum (Cyanogens) in Blue Milk. 



" Synzanthinum (Zanthogens) in Yellow Milk. 



" CEruginosum in Red Milk. 



