PAET FOURTH. 



GERMICIDES AND ANTISEPTICS. 



A KNOWLEDGE of the vital resistance of the 

 various species of bacteria to the action of differ- 

 ent chemical reagents is important from several 

 points of view. First, such information has an 

 important bearing upon elementary biological 

 problems, which are best studied in these simple 

 unicellular plants; second, practical sanitation, and 

 the preservation of various food-products, depend 

 to a considerable extent upon the proper use of 

 germicides and antiseptic's; and, third, modern 

 therapeutics has been largely influenced by the 

 indications which this knowledge seems to furnish 

 for the treatment of infectious diseases and surgi- 

 cal injuries. 



By a germicide agent we mean one which has 

 the power to destroy the vitality of the various 

 species of bacteria known to us, including those 

 disease-germs which have been demonstrated, 

 such as the anthrax bacillus, the bacterium of 

 symptomatic anthrax, the micrococcus of fowl- 

 cholera, that of septicaemia in the rabbit, etc. 



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