1871.) 243 
D. ON GrowtH Force. 
From such examples as those that precede, but more especially from 
the last, it seems necessary to believe that there resides in organ- 
ized matter, and in its most unmodified representative, the nucleated 
cell, an affection which displays itself in repetition. This phenomenon 
reduced to its lowest terms, may mean cell-division only, but the proof 
is only clear in cases of growth proper. This affection displays itself in 
very slow or more rapid repetitions,—cell-division in growth occurring 
rapidly, while its recurrences at rutting seasons in the development of 
horns, feathers, etc., are separated by long intervals of time. In accele- 
ration these repetitions occur with increased rapidity, ¢.¢., in the adding 
of more structures during the same growth periods, while in low types 
its repetitions are few and therefore slow. : 
What is the relation of cell division to the forces of nature, and to 
which of them as a cause is it to be referred, if to any? The animal or- 
ganism transfers solar heat and the chemism of the food (protoplasm) 
to correlated amounts of heat, motion, electricity, light (phosphores_ 
cence), and nerve force. But cell-divisionis an affection of protoplasm 
distinct from any of these ; although addition to homogeneous lumps or 
parts of protoplasm (as in that lowest animal, Protamaba of Heckel,) 
should prove to be an exhibition of mere molecular force, or attraction, 
cell-division is certainly something distinct. It looks like an exhi- 
bition of another force, which may be called growth force. It is corre- 
lated to the other forces, for its exhibitions cease unless the protoplasm 
exhibiting it be fed. 
Professor Henry pointed out many years ago that this must be the case, 
basing his belief on the observed phenomena of growth in the potato, and 
in the egg. The starch of the potato weighs much more than the young 
shoot of cellulose, etc., into which it has been converted by growth ac- 
tivity, so that a portionof the substance of the tuber has evidently escaped 
in some other direction. This isshown to be carbonic acid gas and water, 
derived from the slow combustion of the starch, which inthus running down 
from the complex organic state, to the more simple inorganic compounds, 
evolves an amount of force precisely equal in amount to the chemical 
force (or chemism) requisite to bind together the elements in the more 
complex substance.* 
Carpenter also states that in his opinion the growth of the Fungi is 
produced by a force liberated by the retrograde metamorphosis of their 
food, which is of an organic character, (7. e., humus). This metamor- 
phosis consists, as in the tuber, in the production of carbonic acid gas 
and water, and a force equivalent to the chemism which had bound them 
in the former complex union.+ But in higher forms of vegetable life and 
in growth that follows germination, the plant must appropriate carbon 
from the carbonic acid of the atmosphere. The decomposition of the 
* Agricultural Report of the Patent Office, 1857. 
t Correlation of Physical and Vital Forces, 1864, (Quarterly Journal of Science.) , 
