DISINFECTANTS. 51 



Water is the next great disinfectant employed by na- 

 ture, although moist bodies decay more rapidly than dry. 

 It is a disinfectant by the process of washing, which is 

 mechanical. It is in this way that each shower of rain 

 becomes a natural disinfectant. Light is another disin- 

 fectant, which seems to have been overlooked by many, 

 when their barns and stables were built. Without light, 

 the rose would lose its color, and man and animals would 

 lose and never attain their vigor. 



In proof of the advantage of light, in maintaining 

 health and warding off disease, it is stated that in a bar- 

 rack at St. Petersburg, there was only one case of dis- 

 ease on the side laid open to the light, to three on the 

 dark side. 



Heat and cold are two agents highly useful as disin- 

 fectants. Heat prevents fermentation and decay by 

 drying and changing the chemical state of substances, as 

 it were, by cooking, whether by fire or the sun. Cold, 

 again, is the most powerful antiseptic and disinfectant. 

 Frosts prevent decay and disease, and at the same time 

 share the connection existing between them. 



1. Artificial Disinfectants. — Creosote is a most 

 powerful antiseptic and disinfectant, when applied to a 

 part, but it is not easily managed. Smoke is another 

 good antiseptic, as it contains a little creosote. By it 

 herring and other fish are preserved. 



Spices, and other aromatic substances, have long been 

 used as disinfectants, but they possess no such property, 

 as they do not prevent decomposition of bodies: they 

 merely cover the smell. 



Chloride of lime and chloride of zinc act as good disin- 

 fectants. 



The chloride of manganese is certainly as economical a 



