XVI.] ON THE THEORY OF CHEMICAL CHANGES. 427 



to those higher processes which give rise to new species by a 

 complete change in the specific phenomena of bodies. In the 

 capacity of such complete change consists the chemical activity 

 of matter. 



It is necessary to distinguish between the production of new 

 species differing in physical characters, and that reproduction 

 which belongs to organic existences. The distinction arises 

 from that individuation which marks the results of organic life, 

 and is eminently characteristic of its higher forms. The indi- 

 viduality not only of the organism, but of its several parts, is 

 more evident as we ascend the scale of organic life, while inor- 

 ganic bodies have a specific existence, but no individuality; 

 division does not destroy them. Crystallization is a commence- 

 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 soluta. 



That mode of generation which produces individuals like the 

 parent can present no analogy to the phenomena under con- 

 sideration ; metagenesis, or alternate generation, and metamor- 

 phosis are, however, to a certain extent, prefigured in the chem- 

 ical changes of bodies. Their metagenesis is effected in two 

 ways ; by condensation and union on the one hand, and by ex- 

 pansion and division 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. Metamor- 

 phosis is in the same manner of two kinds ; in metamorphosis by 

 condensation only one species is concerned, and in metamor- 

 phosis by expansion the result is homogeneous, and without 

 specific difference. 



The chemical history of bodies is a record of these changes ; 

 it is in fact their genealogy. The processes of union and divis- 

 ion embrace by far the greater number of chemical changes, in 

 which metamorphosis sustains a less important part. By union, 

 we rise to indefinitely higher species ; but in division a limit is 

 met with in the production of species which seem incapable of 

 further division, and these, being regarded as primary or origi- 



