CHAPTER II. 



STERILIZATION DISINFECTION ANTISEPSIS- 

 FOOD PRESERVATION. 



Definitions. By sterilization is meant the killing or the re- 

 moval of all micro-organisms in or on a body or substance. 

 Disinfection has a somewhat analogous signification, but denotes 

 the destruction or removal of infectious microbes, and this may 

 or may not be accomplished without complete sterilization, 

 according to the nature of the particular case in hand. Anti- 

 sepsis means the inhibition of growth of micro-organisms with- 

 out ordinarily killing or removing them, and is especially applied 

 to the checking of microbic activity in wounds and the effects 

 produced thereby (sepsis). Food preservation involves similar 

 principles, depending upon the prevention of microbic activity 

 in dead organic matter either by sterilization or by the presence 

 of inhibitive substances, similar to antiseptics, but in this instance 

 called preservatives. 



In connection with sterilization we shall consider those agents 

 which remove or destroy a part of the microbic flora without 

 producing complete sterility, as well as the methods which insure 

 complete sterilization. A few examples of each general class 

 will be considered. 



Physical Sterilization. Among the physical means by which 

 sterilization may be accomplished, those which are merely me- 

 chanical may be mentioned first. The removal of microbes from 

 an infected surface by washing them away is a method of wide 

 application. Complete sterility may sometimes be attained in 

 this way. In ordinary disinfection of woodwork, walls and 

 floors, or of the hands, mechanical cleaning is of primary impor- 

 tance, even though it does not insure complete sterilization. 



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