T. S. Hunt on the Theory of Chemical Changes. 227 
ment of individuation, and crystals like the tissues of plants and 
animals, must be destroyed before they can become the subjects 
of chemical change; “corpora non agunt nisi sint soluta.” 
- That mode of generation which produces individuals like the 
parent, can present no analogy to the phenomena under consider- 
| is or alte tion, and met hosis, are 
Vision on the other. In the first case, two or more bodies unite, 
and merge their specific characters in those of a new species. In 
the second case, this process is reversed, and a body breaks up 
into two or more new species. Metamorphosis is in the same 
manner of two kinds; in metamorphosis by condensation, only 
one species is concerned, and in that by expansion, the result is 
homogeneous, and without specific difference. 
_ The chemical history of bodies is a record of these changes ; 
tis in fact their genealogy. The processes of union and divis- 
altemate with each other, and a species produced by the first, may 
Yield by division, species unlike its parents. [rom this succes- 
0n results double decomposition or equivalent substitution, which 
always involves a union followed by division, although under the 
lary conditions, the process cannot be arrested at the inter- 
late stage, 
The prevalence of certain modes of division in related species, 
8iven rise to the different hypotheses of copulates and radi- 
cals, which have been made the ground of systems of classifica- 
on; but these hypotheses are based on the notion of dualism, 
1 and can have no place in a theory of the science. A bod 
May divide into two hs more new species, yet it is evident that 
may ia ible with 
Yield other species whose preéxistence is incompatible witt 
we st hor can sis preéxistence of any species but those which 
t have called primary, be admitted as possible. Apart from 
tettena, or those of its derived species, can ever be a subject of 
“lenee, for it transcends the limits of hnman knowledge. 
