Prof. LeConte on the Correlation of Forces. 137 
of the partial decomposition is to change the food from an inso- 
luble to a soluble form ; and this can be done only by elimina- 
tion of a portion of the carbon in the form of carbonic acid. 
According to the view which I now present, the food is always 
laid up in a more highly carbonized condition than is wanted, in order 
that force may be set free by elimination of superfluous carbon. Ac- 
cording to the ordinary view, if an insoluble food could be found 
capable of conversion into the soluble form without loss of car- 
bon, then germination of the seed might take place without 
loss of weight, by the direct conversion of heat into vital force. 
According to my view, decomposition, and therefore loss of weight 
is absolutely necessary to develope the organizing force, the loss of 
weight being in fact the exact measure of that force. 
3rd. As soon as the plant developes green leaves, a complete 
change takes place in its mode of development. It no longer 
loses weight, but increases in weight. It not only developes, but 
grows. The reason of this is that the organizing force is no 
longer developed by decomposition of food laid up within its 
own tissues, but by the decomposition of food taken ab externo. 
Sunlight is universally admitted to be the physical force con- 
cerned in this decomposition. Further, it is generally supposed 
that there is a direct and immediate conversion of light into 
vital force in the green leaves of plants. But evidently this is 
impossible, since the work done by the light is the separation of the 
two elements carbon and oxygen. Light is therefore converted into 
motion. It is therefore the chemical affinity thus set free which 
is the force immediately converted into vital force. The food of 
plants consists of carbonic acid, water, and ammonia (CO?, HO 
and NH’), or in some cases, according to M. Ville, of CO?, HO 
and N*. Sunlight acting through the medium of the green 
leaves of plants has the remarkable power of decomposing CO*. 
The force thus set free from a latent condition, or the chemical 
affinity of carbon in a nascent condition, is the force by means of 
which C, H, O and N are raised to the organic conditiont. To 
return to my former illustration: matter (oxygen) falling from 
the second to the first plane developes force sufficient to raise 
other matter from the second to the third plane. Thus it is 
evidently impossible, on the principle of conservation of force, that 
* See review of the controversy between Boussingault and Ville on this 
subject, Bibl. Univ., Arch. des Sci. vol. xxx. p. 305. Also Phil. Mag. S. 4. 
vol. xiii. p. 497. Ann. des Sci. S. 4. vol. ii. p. 357. Amer. Journ. Science, 
vol. xix. p. 409. Bibl. Univ., Arch. des Sci. vol. xxviii. p. 335. Ann. des 
Sci. S. 4. vol. vii. p. 5. 
tT Ammonia is also probably decomposed in the tissues of the leaves of 
— (Carpenter, ‘‘ Correlation of Physical and Vital Forces,” Phil. Trans, 
0, p. 732. See also Morren, Bibl. Univ., Arch. des Sci., New Series, 
vol. v. p. 84). This would of course produce additional organizing force. 
