50 THE CHEMISTRY OF CATTLE FEEDING 



On further heating with dehydrating agents they lose a second 

 molecule of water and are converted into nitriles. 



CH 3 .CO.NH 2 -> CH 3 CN + H 2 O 



By addition of hydrogen, nitriles are converted into amines. 

 CH 3 CN + 2 H 2 -> CH 3 .CH 2 .NH 2 



Amines, of the type of ethylamine, retain the basic 

 character of ammonia. The lower members of the series are 

 soluble in water, have a strongly alkaline reaction, and com- 

 bine with acids to form salts. 



CH 3 .CH 2 .NH 2 + HC1 -> CH 3 .CH 2 .NH 3 C1 



These salts are generally soluble in water, neutral and crystal- 

 line. They may be regarded as ammonium chloride in which 

 an atom of hydrogen is replaced by the alcohol radicle. 



Amino-acids, e.g. amino-acetic acid, belong to two types 

 at once. They have the basic properties of the amines proper 

 and also the acidic properties of the original acids. They can 

 therefore form salts both with acids and with bases. 



HO.OC.CH 2 (NH 2 ) HO.OC.CH 2 (NH 3 )Cl 



(Glycocine.) (Glycocine hydrochloric! e.) 



CH 2 (NH 2 ).CO.ONa 



(Sodium glycocolate.) 



But these two kinds of properties are incompatible ; the one 

 neutralises the other, and the compounds are neutral, soluble, 

 crystalline, salt-like bodies. There is reason to believe that 

 this condition arises from an actual combination of the acidic 

 with the basic part, i.e. that the hydrogen of the acid is trans- 

 ferred to the nitrogen, and the latter is joined to the oxygen 

 of the acid, as in the case of ammonium salts (NH 4 .O.NO 2 ). 

 The formula of glycocine is not therefore generally written 

 as NH 2 .CH 2 .CO.OH, but as 



By replacing one or more of the hydrogen atoms in the 



