96 
DR. A. W. HOFMANN’S RESEARCHES REGARDING THE 
lation ; I have however no doubt that even the illustrious propounder of this view is 
at present far from believing that all the organic bases are amidogen-compounds. 
The progress of our knowledge has changed the form of this view, without shaking 
its foundation. A good theory is more than a temporary expression of the state of 
science, collecting under a general view the facts acquired up to the moment of its 
birth. It will not, like ephemeral hypothesis, vanish before the light of succeeding 
discoveries, but expanding with the growth of science, it will still correctly represent 
the known facts, though of necessity modified into a more general expression. 
Such a theory then was that of Liebig. Resting as it did, upon the facts observed 
in the formation of the neutral amides, it was, as originally framed, an expression of 
the knowledge we then possessed. Subsequent researches show^ed that it was not 
only the 1 equiv. of hydrogen (the abstraction and replacement of which had led us 
to amidogen and the amides) that could be removed from the ammonia, but that 
similarly 2 equivs., and even the whole of the hydrogen could be withdrawn from 
their position in this base and substituted by other atoms, as in the imides and 
nitriles. 
If then we give to Liebig’s view the extension of which it naturally admits, and 
which is demanded by the onward steps of science, we arrive at a more general 
conception of the nature of the organic bases ; amidogen and the amides now pre- 
senting themselves to us only as particular instances of the permutations possible 
among the elements of the primary type ammonia. It seemed but logical to look 
among the bases for analogues too of the imidogeti-compounds and the nitriles. In 
other words, it appeared desirable to inquire whether the several equivalents of 
hydrogen in ammonia could not be replaced, not only by atoms neutralizing the 
basic properties of the original system, but also by elements or groups of elements, 
not affecting, or but slightly modifying the alkaline character of the primary com- 
pound. Were this possible, we should arrive at the formation of three classes of 
organic bases, derived from ammonia by the replacement respectively of 1, 2 or 3 
equivalents of hydrogen. 
Expressed in formulae, these compounds would be — 
"] 
H' 
H 
■N= Ammonia. 
^N=Bases of the first class 
, provisionally called amidogen-bases. 
XJ 
HI 
X 
Y. 
X 
Y 
^N=Bases of the seeond class, provisionally called imidogen-bases. 
^N= Bases of the third class, provisionally called nitrile-bases. 
ZJ 
