462 Our Surroundings 



In selecting a site for a home, one should make sure that the 

 land is well drained, that an ample supply of pure water is eas- 

 ily available, that other buildings are not so close as to shut off 

 sunlight and fresh air, and that space for play is sufficient. The 

 home site should not be near buildings used for industries that 

 create unhealthy or odorous conditions. In the house itself care- 

 ful attention should be paid to proper plumbing, ventilation, and 

 heating. 



Disinfection. A disinfectant is an agent capable of destroy- 

 ing disease germs. It is a germicide. A disinfectant thus has a 

 definite purpose and should be distinguished from an antiseptic and 

 a deodorant. A deodorant is an agent which merely destroys 

 offensive odors. It may or may not be a disinfectant or an 

 antiseptic. Disinfection, to be effective, must be carried out 

 with the strictest attention to minute details. It has been well said 

 that "there can be no partial disinfection of infectious material; 

 either its infectious power is destroyed or it is not. In the latter 

 case there is failure to disinfect." Merely to remove an odor or 

 to stop for a while the growth of germs does not disinfect. Dis- 

 infection kills germs. 



It should always be kept in mind that sunlight is an excellent 

 disinfectant. Aside from this, the methods of disinfection most 

 commonly used may be classed as thermal and chemical. Thermal 

 means pertaining to heat. Fire is of course the most effective 

 thermal disinfectant, since it oxidizes all organic matter. Where 

 the use of fire as a disinfectant would result in the destruction 

 of valuable property, such as expensive clothing and hangings, 

 steam is often used. Steam at 240 degrees Fahrenheit is said to 

 kill very quickly even the most resistant spores as well as ordinary 

 germs. Dry heat is not so penetrating and hence not so effective 

 as moist heat, and should be used only when the articles disinfected 

 would be injured by moisture or by chemicals. 



In the use of the chemical method, formaldehyde is regarded 

 as one of the best disinfectants. It may be used in a gaseous or 

 a liquid state. Clothing, rugs and curtains are quickly sterilized 

 when exposed to its action. Chloride of lime is one of the cheapest 

 and best disinfectants. It should contain at least 35 per cent 



