INFECTIOUS GERMS. 



nnHE spread of the new cattle disease, epizootic 

 aphtha, in this country, under circumstances 

 so remarkable, has awakened in the minds of farm- 

 ers and others a desire to leanj something of the 

 nature of the contagious principle, and the myste- 

 rious manner in which it is communicated from 

 one animal to another. 



An agent of infection so subtle that a dog or cat 

 walking through a barn where diseased animals 

 are kept, and then running four or five miles in 

 the open air and entering another barn, infects a 

 herd of healthy animals without contact, must be 

 regarded as extraordinary in its nature. After 

 all, it is no more extraordinary or wonderful than 

 the infectious germs of small-pox, scarlet fever, or 

 measles, which are readily conveyed very long 

 distances in the clothing, and in the air, and which 

 remain uninfluenced by meteorological agencies, 

 heat and cold, wet and dry. The susceptibility 

 of different individuals to the influence of -conta- 

 gious germs is no less wonderful than the nature 

 of the germs themselves. It may be said that no 

 two persons are affected alike by them, and it is 



