151 



ammonium may be replaced by an equivalent of a mono-atomic 

 electro-positive radical, such as methyl, ethyl, &c. ; a series of com- 

 pound ammoniums being produced, the salts of which may be thus 

 formulated : 



H 



N<^ g' yd 



R' 

 R' 

 H 

 H 



Cl, 



LR' 

 R' representing a mono-atomic electro-positive radical. 



These successive substitutions were accomplished by the action of 

 ammonia upon the bromides and iodides of the alcohol-radicals, 

 which since that time have become most valuable agents of substi- 

 tution in the hands of chemists. 



All the bases produced by this process being derived from 

 1 equiv. of ammonium, contain 1 equiv. of nitrogen ; they differ 

 in this respect essentially from the majority of the alkaloids extracted 

 from plants, and more particularly so from those which, like quinine, 

 morphine, strychnine, &c., specially claim our interest. By far the 

 greater number of the vegetable alkaloids contain 2 equivs. of nitro- 

 gen. In some vegetable and animal bases we find even 3 and 4 equivs. 

 of nitrogen. The molecular construction of these bodies is still ob- 

 scure, but it is extremely probable that they are derived from 2, 3 or 

 4 ammonia equivs., in which the hydrogen is more or less replaced 

 by poly-atomic molecules, and that the stability of such complicated 



