804 ETHYL AND AMMONIUM SERIES. 



rence between the two series depends upon a chemical diffe- 

 rence in the characters of their radicals ; acetyl being capable of 

 forming acids, while amidogen does not possess that pro- 

 perty. 



Expressing amidogen NH 2 by Ad, and acetyl C 4 H 3 by Ac, 

 the following pairs of compounds from the two series will be 

 found to correspond in composition, differing only in the one 

 containing acetyl while the other contains amidogen. (Liebig's 

 Traite). 



