CHAPTER III. 



THE DESTRUCTION OF BACTERIA, STERILIZATION 

 AND DISINFECTION. 



THE knowledge of the means by which bacteria 

 are destroyed underlies the methods employed in dis- dls t k> f n ec ~ 

 infection, sterilization, and antisepsis as they are used 

 in preventing the spread of infection. The term dis- 

 infection means the total destruction of bacteria by 

 any agent, while sterilization is limited to the destruc- sterili . 

 tion of- bacteria by heat. An antiseptic is a chemical and^nti- 

 agent that prevents the growth and multiplication of 

 bacteria, but does not necessarily destroy them. A 

 deodorant is a substance that masks offensive odors 

 or substitutes an agreeable odor for a disagreeable 

 one. Some of the disinfectants and antiseptics are also 

 deodorants, but few of the deodorants have disin- 

 fectant properties. 



The agents that affect bacteria injuriously may Physical 

 be physical or chemical. Among the physical agents 

 may be mentioned drying, light, and heat. 



Drying prevents the growth of bacteria and will 

 eventually destroy them. The spores of bacteria, how- 

 ever, will resist drying for a much longer time. It is 

 for this reason that the bacterial content of dust is 

 chiefly in the form of spores. The effect of drying is 

 influenced by the temperature at which the drying 



2 (17) 



