284 APPLIED BACTERIOLOGY 



putrefactive processes : hydrogen, nitrogen, phosphuretted 

 hydrogen, sulphuretted hydrogen, carbon dioxide, marsh - 

 gas, formic acid, valerianic acid, many of the volatile and 

 fixed fatty acids, free ammonia, ammonium sulphide, tri- 

 methylamine, propylamine, indol, scatol, etc. 



The particular products yielded in putrefactive and fer- 

 mentative processes vary necessarily with the composition 

 of the decomposing material, the prevailing conditions, and 

 with the species of organisms present. Many of the 

 gaseous and volatile products of putrefaction are charac- 

 terised by their very offensive smell. The anaerobic bacteria, 

 generally speaking, give rise to the most malodorous pro- 

 ducts. In ■ the case of a decomposing body of an animal, 

 the odours evolved are worse in situations where oxygen has 

 not free access. Anaerobic organisms are always present in 

 the intestines, and after death they quickly invade the 

 whole body, and grow under very favourable conditions as 

 to temperature, the interior of the body providing in every 

 way a suitable pabulum for their growth. The aerobic 

 organisms on the surface of the dead body possibly assist 

 the putrefaction in the interior by consuming the oxygen. 

 The products of the putrefactive anaerobes are marsh-gas, 

 sulphuretted hydrogen, and free hydrogen, with traces of 

 such foul-smelling bodies as scatol, etc. 



The products of decomposition evolved by the aerobic 

 bacteria upon the surface are generally more simple in 

 character, and consist mainly of carbon dioxide and 

 ammonia. 



