130 Biological Chemistry. 



the air ; the hydroxide is, in fact, a stronger base than am- 

 monia. The hydroxides readily neutralize acids 



N(C 2 H 5 ) 4 OH + HC1 = N(C 2 H 5 ) 4 C1 + H,0 



SUMMARY. The amines may be regarded as alkyl 

 substitution products of ammonia, in which one, two, or 

 three hydrogen atoms may be substituted by an alkyl 

 group to form respectively primary, secondary, or tertiary 

 amines. They can be prepared by the interaction of 

 alkyl iodides and an alcoholic solution of ammonia. 

 The primary amines can also be formed by the action of 

 potassium hydroxide and bromine on acid amides, which 

 yield an amine with one carbon atom less ; they can 

 also be obtained by the reduction of nitriles. The three 

 classes can be distinguished from one another by the 

 differences in their behaviour towards nitrous acid, the 

 primary compounds giving alcohols with evolution of 

 nitrogen, the secondary nitroso derivatives, whilst the ter- 

 tiary do not react. The primary amines also give the 

 characteristic carbylamine reaction. Tertiary amines 

 yield with alkyl iodides (or bromides) the crystalline 

 quaternary ammonium iodides or bromides, from which 

 hydroxides and other derivatives can be obtained. 



Similar phosphorus and arsenic compounds are known. 



Part XIV. Nitriles, Isonitriles, and other Allied Nitrogen 

 Compounds. 



When nitrogenous refuse, such as horn-shavings, hair, 

 etc., are heated with iron and potassium carbonate to a 

 high temperature, and the fused mass is afterwards ex- 

 tracted with hot water, a solution is obtained which 

 deposits on concentration lemon-yellow hydrated crystals 

 of the composition K 4 Fe(CN) 6 4H 2 0. This so-called yellow 

 prussiate of potash, or potassium ferrocyanide, has been 



