MEAT BACTERIA 



153 



the health authorities get busy and almost invariably find the true 

 source of the trouble, and there the matter usually rests. No ra- 

 tional attempt is made to prevent a repetition of the occurrence. 

 Meats of all kinds when left exposed to the air soon show signs 

 of decomposition. The aerobic forms of bacteria are first to de- 

 velop, causing the decomposition of proteids and sugars. Inas- 

 much as sugar is usually present in small amounts only, the sugar 

 decomposers are soon crowded out by the proteid-splitting forms. 

 The small amount of acid formed by the sugar decomposers is 

 neutralized by the ammonia which is formed during proteid de- 

 composition. The aerobes very naturally act on the outside of the 

 meat particles, using up the oxygen in the air on and within the 

 immediate surface tissues of the meat. This reduction in oxygen 

 gradually permits the anaerobes to get a start, especially B. per- 

 fringens and B. bifermentens sporogenes. These use up proteids 

 as well as sugar, and the complete removal of sugar encourages 

 the more active development of pure aerobes which act upon 

 proteids only. The following tabulation from the work by Ellis 



