2^4 APPLIED BACTERIOLOGY 



If the former, they are composed of carbon, hydrogen, 

 nitrogen, and oxygen ; if the latter, the oxygen is wanting. 

 Non-volatile amides are solid ; on the other hand, volatile 

 amines are liquid. 



The chemical constitution of many of the alkaloids and 

 ptomaines can be illustrated by the following constitutional 

 formulae : 



I 



HC- 



H H H^ 



C C 



\ 

 — CH 



I 

 -CH 



/ \ 



I I 



HoC CHo 



\ / 



CNN 



H H 



Benzine. Pyridine. Piperidine. 



As is seen from the above formulae, pyridine is very 

 nearly related to benzine, from which it is easily obtained 

 by replacing one of the CH groups by nitrogen. Both 

 benzine and pyridine have some of their carbon bonds 

 unsatisfied, so that each C and the N having a bond free 

 to combine with other atoms or groups of atoms, there 

 is the possibility of a very large number of addition and 

 substitution derivatives being formed. Perhaps the most 

 simple case is the following. All the free bonds in pyridine 

 may be satisfied by the addition of a single atom of hydrogen 

 to each, when the result is the production of the alkaloid 

 piperidine. 



Leueomaines. — Gautier first pointed out the fact that 

 certain bodies of an alkaloidal nature are produced within 

 and by the living tissues of the animal body. These are 

 without doubt the result of the metabolism of the pro- 

 toplasm, or they may be the result of the decomposition of 

 albuminoid substances within the body. The leueomaines 

 exist in very small quantity in normal urine, but they very 

 largely increase in quantity in certain diseases. 



