26o BACTERIA, YEASTS, AND MOLDS 



proportion of about one part acid to twenty parts water, 

 although sometimes it may be weaker and sometimes 

 stronger. A solution of one part to twenty may be used 

 for washing the hands, but stronger solutions will produce 

 a burning of the skin. It may be employed for almost any 

 of the purposes for which corrosive sublimate is used, but 

 its value is less and its cost is considerably greater. One 

 of the reasons for its popularity is the fact that it pos- 

 sesses a distinct odor, and people who do not properly 

 understand the matter of disinfection have an impression 

 that a disinfectant ought to have a strong odor.. It should 

 be understood thoroughly at the outset that deodorants 

 are not disinfectants. Substances with strong smells do not 

 ordinarily have any value as disinfectants. The odor of 

 carbolic acid is almost without value, and the security 

 which people feel when a disinfected room is filled with 

 carbolic acid fumes is wholly misplaced. To disinfect 

 the air requires materials of a different nature, and car- 

 bolic acid is not more useful as a disinfectant than are 

 many other antiseptics that emit no odor at all. Corro- 

 sive sublimate, for example, is very much more effica- 

 cious than carbolic acid, although it is totally without 

 odor. It may frequently be desirable in a sick room to 

 have a deodorant as well as a disinfectant ; but this is for 

 comfort rather than for safety, and other deodorants can 

 be employed which are equally as efficacious as carbolic 

 acid. The burning of coffee grains in a room will usu- 

 ally destroy offensive smells and serve as a deodorant, 

 although it is valueless as a disinfectant. 



Chloride of Lime. This is one of the cheapest and at 

 the .same time one of the best disinfectants. It may be 



