ORGANIC BASES. 197 



stitiition, which forms the basis of our present views as to this interest- 

 ing branch of chemistry. He assumed that ammonia was the type of 

 all orp^anic bases, and that it was itself such a base, of the simplest 

 composition. Ammonia consists of only two elements, containing one 

 atom of nitrogen and three of hydrogen in one molecule.* Liebig as- 

 sumed that, in the organic bases, a part of the hydrogen was replaced 

 by other radicals, composed of several elements; these bases might 

 therefore be considered as made up of a compound radical and a combi- 

 nation of one atom of nitrogen with only two of hydrogen, the other 

 atom of hydrogen being replaced by the new radical. The compound 

 thus formed is called amid.t Such a base is called an amid base.f 



Liebig developed this idea in the clear and ingenious manner peculiar 

 to himself, and expressed his views concerniug the probable nature of 

 compounds which could be formed from amid and the alcohol radicals. 

 Ten years later his ideas were verified by experiment. Ethylamine, and 

 a wljole series of similar bases, were produced by Wurtz in Paris in 

 1849. 



These discoveries of the celebrated French scientist justly excited un- 

 usual attention, which was still increased when A. W. Hofmaun and 

 Wurtz demonstrated that not only one atom of hydrogen in ammonia 

 could be replaced by an alcohol radical to form amid bases, but that 

 compound radicals could be substituted for two, and even for all three, 

 atoms of hydrogen. These bases might be designated as primary, sec- 

 ondary, and tertiary amid bases, according as one, two, or three atoms 

 of hydrogen of the ammonia ha^e been replaced by compound radicals. 

 (In English treatises on chemistry they are usually designated as amid, 

 imid, and nitril bases. — The Translator.) Their chemical formulae are rep- 

 resented by the following table, in which A, B, C, stand for the compound 

 radicals. 



Ammonia base. Amid base. Imid base, Nitril base. 



H) A) A) A) 



H }n H }n B Vn B >a 



H ^ H ^ H ^ C ^ 



As Hofmann has shown later that there is a series of compound rad- 

 icals which may replace two atoms of hydrogen in the doubled formula 

 of ammonia, producing a second extensive series of bases, whose com- 

 position is expressed in the following table, where A^ B^ and C^ repre- 

 sent the compound radicals. 



H: ) AM AM A' ) 



H. }U2 Hi ;u.2 B' }U2 B' Uj 



H: S Hj ) H: ) C S 



If we suppose only 52 such compound radicals capable of replacing 

 one atom, and 32 of replacing two atoms of hydrogen, we obtain 

 3.5,000 millions of possible compound organic bases. 



* The symbol N, (lutrojfen,) in chemical formulae, meaus oue atom of iiitrogeu, and 

 H one atom of hydrogen. The formula for ammonia is therefore : H+H-f H+N= H3N. 



t The chemical formula of amid is therefore : H- N. 



t The formula for an amidogen base is : A-j-Ho N, in which A stands for a compound 

 radical. 



