528 The American Naturalist. (June, 
force and matter exist, there is no reason to deny that they may 
produce the root and stem and leaves of the plant, of materials 
which will enter into the cycle of changes now effected at 
greatly higher or lower temperatures, thus preserving the rate 
and kind of change, while altering the materials which undergo 
it. This result would be a metasomatic evolution. On the other 
hand, the greater rapidity or slowness of these reactions ‘might 
change the character of the organism, while the material remained 
unchanged, which would produce a metagenetic evolution. Or 
both substance and rate might alter, giving rise to an entirely 
different world, with different organisms and different processes, 
and as far from our present world as is the spiritual from the 
material. 
To resume the case: 1. A careful study of the modes of 
growth in the three kingdoms of nature—mineral, plant, and ani- 
mal—shows that there are strong analogies between them, the 
divergence being progressive in the order named, though many 
of the strongest characteristics, such as sensation, etc., of the 
highest or animal kingdom, are of such a kind that we are pre- 
vented from knowing their presence or absence in the other 
kingdoms. 
2. The characteristics common to all three kingdoms are the 
presence of force; its action upon matter; and its renewal by the 
change of one form of matter to another, in the course of which 
energy is manifested. ; 
3. In the crystal kingdom the restrictions on the existence and 
growth of the individual being least, and the variations of condi- 
tions and environment in which existence is possible, greatest, 
the individuals are more numerous and their composition more 
diverse, all of the known and unquestionably many as yet unknown 
elements uniting to form them. 
4. Asto the plant and animal kingdom the cycles of changes 
are based for the most part upon the disunion and separate com- 
binations of carbon and hydrogen, because, at the existing tem- 
perature, pressure oxygen-atmosphere, and sunlight, these changes 
can be produced to the greatest advantage of existing kinds of 
living things and life forces. 
