216 REFUTATION OF THE SALT RADICAL THEORY, 
Of Liebig's " Principles" so called. 
90. Under the head of the "theory of organic acids," in 
Liebig's Treatise on Organic Chemistry, we find the fol- 
lowing allegations dignified by the name of principles. 
Manifestly they must tend to convey a false impression to 
the student, that hydrogen has a peculiar property of creat- 
ing a capacity for saturation, instead of being only the mea- 
sure of that capacity, as is actually true, and likewise that 
in this respect it has a peculiarity which does not exist. 
91. The allegations to which I refer are as follows, being 
a literal translation from the French copy of the Traite of 
Liebig, page 7: — 
"The hydrated acids are combinations of one or more elements with 
hydrogen, in which the latter may be replaced wholly or in part by 
equivalents of metals." 
" The capacity of saturation depends consequently on the quantity of 
hydrogen which can be replaced. 
*< The compound formed by the other elements being considered as a 
radical, it is evident that the composition of this radical can exercise no 
influence on the capacity of saturation. 
"The capacity of saturation of these acids augments or diminishes in 
the same ratio as the quantity of hydrogen, not entering into the salt 
radical, augments or diminishes. 
"If into the composition of the salt radical there should be introduced 
an undetermined quantity of any elements, without changing the quan- 
tity of hydrogen extraneous to the radical, the atomic weight of the 
acid would be augmented, but the capacity of saturation would remain 
the same." 
92. As by the advocates of the existence of " salt radi- 
cals /' hydrogen is considered as playing the part of a me- 
tallic radical, and must, therefore, as respects any relation 
between it and the capacity of saturation, be in the same 
predicament as any other electro-positive radical, I cannot 
conceive wherefore laws, which affect every other body of 
this kind, should be stated as if particularly associated with 
hydrogen.* 
* There is, in some respects, a coincidence so remarkable as to the 
part taken by Dr. Kane and myself, with respect to hydrogen, that I 
