42 INFECTION AND IMMUNITY 



surrounding soil, and contaminate some well or stream 

 from which drinking-water is obtained. For this 

 reason privy vaults, cesspools, and sewers should 

 never be allowed to become infected. All infectious 

 material, such as the dejections of patients with 

 cholera or typhoid fever, should be destroyed at its 

 source, in the sick-room ; or, if it is ascertained that 

 such material has been thrown into a privy vault, the 

 entire contents of the vault should be promptly disin- 

 fected. The same rule applies to infectious material 

 thrown upon the ground, or wherever it may be. 



