Visinffdants 207 



conditions for their multiplication, with the 

 usual consequence of causing more or less dis- 

 ease in the family. The human body possesses 

 more or less power of resistance to bacteria, but 

 if these natural forces cannot overcome their 

 invasion, they in turn will be successful and 

 produce disease. 



Once infected with disease -producing bacteria, 

 a house should be renovated from attic to cellar, 

 and subjected to the action of agents possessing 

 the power of destroying the pathogenic or- 

 ganisms. Numerous means are employed to kill 

 bacteria, among them being the use of disin- 

 fectants in the form of liquids or gases, and the 

 application of heat. The list of chemical disin- 

 fectants is long, but owing to their cost, a rela- 

 tively small number are available for the disin- 

 fection of houses. The use of carbolic acid, 

 copperas, whitewash, and the fumes of burning 

 sulfur are familiar disinfectants used for this 

 purpose. Among the disinfectants which can be 

 applied directly to wounds, to prevent suppura- 

 tion, are weak solutions of corrosive sublimate 

 and of carbolic acid. 



The greater number of l^acteria, pathogenic 

 or harmless, which do not form spores, are de- 

 stroyed by a temperature of 155 degrees Fahren- 

 heit for twenty minutes. Very few resist the 

 boiling point; thus water may be made safe by 



