CHAPTER V 



THE DESTRUCTION OF BACTERIA 



GENERAL CONSIDERATIONS 



No branch of bacteriology has been more fruitful in practical 

 application than that which deals with the factors which bring about 

 the destruction of microorganisms. Upon the study of this branch 

 has depended the growth and the development of modern surgery. 



The agents which affect bacteria injuriously are many, and are 

 both physical and chemical in nature. 



When a procedure completely destroys bacterial life it is spoken 

 of as sterilization or disinfection, the term disinfection being em- 

 ployed more especially to designate the use of chemical agents. 

 When the procedure destroys vegetative forms only, leaving the 

 more resistant spores uninjured, it is spoken of as "incomplete 

 sterilization." When an agent, on the other hand, does not actually 

 kill the microorganisms, but merely inhibits their growth and mul- 

 tiplication, it is spoken of as an antiseptic. The term deodorant 

 is indiscriminately applied to substances which mask or destroy 

 offensive odors, and may or may not possess disinfectant or antiseptic 

 value. Some deodorants act chemically on the noxious gases, de- 

 stroying them. 



PHYSICAL AGENTS INJURIOUS TO BACTERIA 



The principal physical agents which may exert deleterious action 

 upon bacteria are: drying, light, electricity, and heat. 



Drying. Complete desiccation eventually destroys most of the 

 pathogenic bacteria, yet great differences in resistance to this con- 

 dition are shown by various microorganisms. Ficker, 1 who has made 

 a systematic study of the influence of complete drying upon bacteria, 

 concludes that the resistance of bacteria to desiccation is influenced 



1 Ficker, Zeit. f . Hyg., xxix, 1896. 



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