BACTERIAL' SECRETIONS 147 



Bacterial Secretions. Besides the decomposition prod- 

 ucts just referred to, another class of new substances is 

 found in the putrefying and decaying food, and these are 

 to be regarded as secretions from the bacteria. Bacteria are 

 living organisms and, like larger animals and plants, are con- 

 stantly emitting from their bodies certain secretions. Our 

 own bodies are constantly secreting materials, like perspira- 

 tion, urea, etc. ; and bacteria, as the result of their activity, 

 are also constantly producing a small amount of secretions. 

 These secretions are totally different products from the 

 original food. The secretions from some species of bac- 

 teria are quite harmless, although others are of an intensely 

 poisonous nature. As a result, a bit of food that is under- 

 going putrefaction may in the course of time become 

 highly poisonous because of the appearance of poisonous 

 materials, part of which may be decomposition products 

 but most of which are probably bacterial secretions. 



Chemists and bacteriologists are not able to separate 

 very clearly decomposition products from the secretions 

 of bacteria, and for our purpose it is quite unnecessary. 

 We need only remember that as the bacteria consume our 

 food products they produce profound chemical changes 

 which we call putrefaction and decay. As the result of 

 these changes not only is a host of highly flavored prod- 

 ucts developed but also another series with strong odors. 

 Some of these new products are poisonous, others are not. 

 All of them have a tendency to be softer than the original 

 food and more easily dissolved in water ; the result of which 

 is that as the food is consumed by the bacteria it becomes 

 softer and more liquid. In the end it largely disappears, 

 being dissolved into gases which pass off into the air and 



