220 BIOLOGY OF SPECIALIZED .GROUPS 



enzymes. Glycerine and the various fatty acids are among 

 the end-products. It is a difficult matter to isolate the par- 

 ticular species of bacteria in putrefying fluids which produce 

 the steatolytic enzymes. 



In order that putrefaction take place, certain of the pre- 

 requisites of bacterial growth must be at hand. A certain 

 amount of moisture is absolutely necessary. It is a familiar 

 fact that protein material, such as meat, when dried, does not 

 decompose. Temperature is another important requirement. 

 Low temperatures prevent the action of the putrefactive 

 bacterial enzymes. Fischer refers to the finding of the Sibe- 

 rian mammoths which had been frozen in the ice for centuries 

 and the flesh was still in good condition. 



The bacteria concerned in the putrefactive processes are 

 aerobic, anaerobic, and facultative anaerobic. The aerobic 

 bacteria by using up the supply of oxygen and forming carbon 

 dioxide thus provide the necessary conditions for anaerobiosis, 

 and consequently the rapid generation of gases and disin- 

 tegration of the compound. Aerobic bacteria in putrefac- 

 tion are, on the whole, of secondary importance. 



Mechanism of Putrefaction. Putrefaction is primarily 

 a process of decomposing and splitting up nitrogenous com- 

 pounds by the action of the proteolytic enzymes of bacteria. 

 It is in a measure a fermentive process. It should be remem- 

 bered that in every case when an animal or plant compound 

 is decomposing that the zymogenic or fermentive bacteria 

 are acting on the carbohydrate compounds at the same time 



