PRACTICAL STERILIZATION AND DISINFECTION 153 



The fresh surface of soil thus exposed may be sprinkled with 

 a solution of a chemical disinfectant as above described. 



Fig. 105. — Formaldehyde gener- 

 ator used in city work for room 

 disinfection. 



Fig. 106.— Government formal- 

 dehyde generator. 



"Portions of walls and ceiling not readily accessible may 

 be disinfected by chlorine gas liberated from chloride of 

 hme by crude carbolic acid. This is accomplished by mak- 

 ing a cone of 5 or 6 pounds of chloride of lime, in the top 

 of which a deep crater is made for the placement of from 



