208 THE FITNESS OF THE ENVIRONMENT 



D 

 OTHER ORGANIC COMPOUNDS 



The organic substances which contain 

 nitrogen are very numerous and exceedingly 

 diverse in their properties. A few of the 

 principal classes of such compounds are the 

 following : — 



Amines R-NH 2 , R 2 NH, R 3 N 



Nitro compounds R — N0 2 



Nitriles R-C = N 



Isonitriles R — NC 



Amino-acids R - CH • NH 2 • COOH 



R-N. 



Azoxy compounds I /O 



R-N x 



Azo compounds R— N=N— R 



Hydrazo compounds R — NH — NH — R 



Derivatives of purine, pyridine, and other 

 ring systems, etc. 



The nitrogenous organic substances include 

 classes of compounds which differ in their 

 properties from any of the non-nitrogenous 

 substances. Of such special properties the 

 most conspicuous is perhaps alkalinity. Like 

 ammonia, of which it is a derivative, the 

 amino group (— NH 2 ), and various other 

 groups containing nitrogen possess this char- 



