268 DECO^IPOSITION 



The Products of Putrefaction. — While the end 

 products CO2 and HoO and ammonia are readily enough 

 recognized, there are a great many intermediate products, 

 many of which are only temporary. The first products 

 are similar to those produced in digestion, and include 

 peptones and albumoses, which are decomposed into 

 the animo-acids. A number of gaseous compounds may 

 also be formed, among which are methane (CH4) and 

 hydrogen sulphide (HoS). Bubbles of methane and 

 sulphuretted hydrogen may often be seen rising from the 

 muddy bottoms of swamps, and sulphuretted hydrogen is 

 given off by rotten eggs and by the decaying remains of 

 plants and animals accumulated in the mud at the bottom 

 of slow-running polluted streams and in ponds. Some- 

 times H and N are also given off. The volatile compounds 

 which characterize putrefaction include mercaptan, skatol, 

 and indol, substances the composition of which has been 

 fairly worked out ; but undoubtedly in addition to these, 

 and associated with putrid odors, are others not yet known 

 which give the characteristic smells to the putrefactions 

 of different materials. 



Ptomaines form one of the most interesting groups 

 of degradation products from protein. They are simple 

 compounds of C, H, 0, and N, produced by bacterial 

 decay in food. They resemble the alkaloids used in 

 medicine and include some of the most violent poisons 

 known. Bacterial toxins, on the other hand, are charac- 

 teristic metabolic products of certain species of bacteria, 

 and are largely independent of the food upon which they 

 are living. 



The Putrefaction Process may be best illustrated 

 by a specific instance. Thus we may discover the body of 

 a cow recently dead, lying on the ground. This body con- 

 tained at the time of deatb many bacteria within its diges- 

 tive tract, and it becomes infected with other destructive 

 bacteria, none of which can be held in check by the dead 

 organism as they would have been had the body continued 



