180 Gerhard? s Organic Chemistry. 



certain ferments, aspara 

 of ammonia. 



The compounds like succinidam which differ from ordinary 

 amides by the elements of water are designated by M. Gerbardt 

 as hydride amides ; they often present acid characters. Prussic 

 acid is anhydride amide of formic acid, in other words the amide 

 of formic anhydride which is carbonic oxyd CO. When formate 

 of ammonia is heated it is directly resolved into this acid and 

 water CH 2 ; NH 3 =2H 2 0+CHN; and when prussic acid is 

 mixed with strong acids, or when its salts are boiled with alka- 

 lies, it reassumes the elements of water and regenerates a formate 

 and ammonia. The cyanic acid is the amide of carbonic anhy- 

 dride (carbonic acid gas), and like the other amides, regenerates 

 ammonia and the acid under the influence of acids and alkalies. 

 A large number of azotized acids are included in this class. 



(Precis, Vol. I, pp. 110-120.) 



Ethers. — These are compounds resulting from the action of 

 mineral and organic acids upon the alcohols, and like the amides 

 contain the elements of both their constituents minus the ele- 

 ments of water. Those of the monobasic acids are formed from 

 one equivalent of the alcohol and one of the acid, by the abstrac- 

 tion of the elements of one equivalent of water. The ethers of 

 the bibasic acids are in a similar manner produced by their reaction 

 upon two equivalents of alcohol. In accordance with the theory 

 of compound radicals, they are regarded as salts of the oxyd of 

 a radical which is derived from the alcohol by the abstraction of 

 the elements of water, but the acids in these supposed salts cannot 

 be detected by the usual reagents ; the chlorid and oxalate of ethyls 

 are not decomposed by salts of silver and lime. When the ethers 

 are heated with a solution of potash, they reassume the elements of 

 water and regenerate alcohol and the acid. In their formation 

 and decomposition these compounds present a close resemblance 

 to the amides ; corresponding to the acid amides we have acid 

 ethers or yimc acids. The bibasic acids with one equivalent of 

 alcohol yield coupled acids (see p. 176) which* are monobasic. In 

 these and similar reactions, « the substances in which hydrogen or 

 one of the elements at the positive extremity of the electrical 

 scale, predominates, are attacked by oxygen chlorine and other 

 elements which are placed at the negative^ extremity of the scale, 

 or by compounds in which these negatively electric elements 

 predominate." The acids, chlorine, bromine and some metallic 

 chtonds are thus electro-negative, while the alcohols, hydro-car- 

 bons and ammonia are electro-positive. This division is of neces- 

 sity only relatively true ; thus benzoic acid by its oxygen is neg- 

 ative to alrnhnl hnt ic n»,;*;~. *. _i.i ...-.._ "\ -.•__; J ttrhicB 



act upon its hydrogen.--(P 



