THE NEW CHEMISTRY. A DEVELOPMENT OF THE OLD. 117 
they at first opposed. Liebig and Wohler’s research on oil of 
bitter almonds led to the discovery of a number of compounds, 
exhibiting many general analogies, which could best be ex- 
plained by supposing the existence in each of a compound radicle, 
or group of atoms. When it became necessary once more to 
adopt the idea of compound radicles, the theory of substitution 
was found to be strengthened, not weakened, thereby. Many 
reactions were made clear by supposing that an element might 
be substituted by a group of elementary atoms, by a compound 
radicle. But in adopting the idea of compound radicles the 
substitutionist yet maintained that the chemical compound was 
a distinct whole, made up of parts he admitted, but, never- 
theless, having these parts so modified and merged in one 
another that the resultant acted as a homogeneous compound. 
Thus when the new school likened the ethers to the metallic 
oxides, they did not mean to assert that the molecule of ether 
was composed of two parts, ethyl and oxygen, held together by 
electric bonds, and ready to part company without difficulty ; 
nor, in asserting that ether was one substance, and not a 
dualistic system, did they deny the existence of a structure 
within the molecule of ether. They admitted the existence of 
a closer relationship between the atoms of carbon and hydrogen 
constituting the group ethyl, than between these atoms and 
those of oxygen, and they generalized the reactions and analogies 
of ether, by saying that it might be regarded as sodium oxide 
in which both sodium atoms had been substituted by two com- 
pound atoms of ethyl. Berzelius had himself likened the ethers 
I to oxide of potassium, and by doing this the great apostle of 
dualism had paved the way for the advance of the unitary 
theory. 
That portion of the dualistic doctrine which was embodied 
in the theory of compound radicles was adopted by the unitary 
schools, but adopted in a modified form : the effects of this 
modification were not long in making themselves felt. 
Berzelius, in his later works, had been ready to give a 
dualistic formula to any compound without stopping to inquire 
into the facts known about that compound : he had tended to 
forsake the only true scientific method, and to substitute the 
; vagaries of his fancy for the facts of nature. The new school 
averred that ‘ compound radicle ’ was an expression generalizing 
a class of facts ; that the reactions of bodies were most simply 
, explained by supposing that when acted on by chemical force 
i the little parts of these bodies behaved as having a definite 
, structure ; and that therefore the formula of a given body might 
| be written as containing different compound radicles under 
different conditions. 
The fault of the old chemistry was that more attention was 
