CHAPTER XV 



PRODUCTS OF METABOLISM 



Introduction. Bacteria differ from other plants in general 

 in that their catabolic properties exceed their anabolic. 

 They are preeminently analytical rather than synthetic 

 organisms. In the multiplication of cells a large amount of 

 organic matter is accumulated in the protoplasm, but this 

 is relatively small compared with the disintegrating processes 

 which they are able to inaugurate. It is proposed in this 

 chapter to consider some of the products of metabolism, prin- 

 cipally, in order that we may understand something more of 

 the nature of the changes which go on in the bacterial cell, 

 but also because the determination of some of these by-prod^ 

 ucts is a matter of great importance in the differentiation 

 of various bacteria. In considering the products of metab- 

 olism, however, it will be difficult to distinguish between 

 those which are produced within the cell and those substances 

 which are formed outside of the cell as a result of the break- 

 ing down of the food substance or the abstraction of certain 

 elements therefrom. In certain cases it is impossible to know 

 whether a particular product is actually formed within the 

 cell or whether it is a split product. Very frequently, from 



171 



