18 The Gemmule vs. the Plastidule as the [January, 
ready to be set free in the dynamic process of fertilization of the 
ovum, and of embryonic development. “‘ Growth force potential 
in the spermatozoid, on its destruction [fusion with the egg] be- 
comes converted into heat or other force. Thus may originate 
the growth force of the ovum, which, once commenced, is con- 
tinued through the period of growth.” It seems to me probable 
that the process of repetition is simply a phase of the manifestation 
of growth force as in the asexual fusion of growing cells, forma- 
tion of spores in low plants and navicelle cysts in Gregaring. It 
seems to me probable, also, that the cleavage of the yelk of the 
ovum supervenes just as soon as the static condition of its mole- 
cules is interfered with by blending with the spermatozodid whose _ 
molecules are in a dynamical or potential condition as aforesaid. — 
It is clear that if this is true, we get a composite result or resultant. 
In point of fact, this is tacitly implied where Prof. Cope says in 
continuation: “ The process might be compared to the application — 
of fire to a piece of wood. The force conversion is communicated — 
to other material than that first inflamed.” That is,the molecular ` 
movements of the embryonic mass, viz., sperm and germ, tends — 
to be assumed by all the material which it appropriates to itself; 
this: may be extended to the process of digestion or appropria- — 
tion of protoplasm in animals and to the formation of protoplasm — 
by plants when in growing conditions from binary and ternary — 
compounds It is also clear that the quantitatively indefinite 
element x of the modifying environment of the plastidule is ad- 
mittedly involved in consideration of the effect of use and effort, 
as held by this distinguished biologist, and that if use and effo 
are modifying causes, and molecular vibrations, whether they be 
-in waves or ellipses or curves of any kind, will be influenced and 
accordingly modified. It must also necessarily be implied that 
these effects are persistent and that they involve the idea o 
Perigenesis quite as much as the plasticule. 
The totality of the phenomena of differentiation and reduction 
(specialization, cephalization) in living forms, are, in view of the 
foregoing considerations, it seems to me, to be referred to dynami- 
cal causes. Laplace, from a mathematical standpoint, saw that 
= this must be so. Lamarck, in his Philosophie Zoologique} in the 
_ chapter VII, tom I, pp. 218-268, entitled, “ Zhe influence of cir- 
cumstances upon the actions of animals,’ has some observations: 
1 Nonvelle Edition, tom. I and II, Baillere, Paris, 1830. 
