PHILOSOPHICAL SOCIETY OP WASHINGTON. 339 



The less difficult problem of the building up of the plant after 

 the consumption of the seed, under the direct action of the solar 

 rays, is then considered ; the leaves of the young plant absorbing 

 by their moisture carbonic acid from the atmosphere, which being 

 decomposed by solar actinism, yields the de-oxidized carbon to 

 enter into the structure of the organism. "All the material of 

 which a tree is built up, (with the exception of that comparatively 

 small portion which remains after it has been burnt, and con- 

 stitutes the ash,) is derived from the atmosphere. In the decom- 

 position of the carbonic acid by the chemical ray, a definite 

 amount of power is expended, and this remains as it were locked 

 up in the plant so long as it continues to grow." And thus 

 under the expenditure of an external force, the plant (whether 

 the annual cellular herb or the perennial fibrous tree) was shown 

 to be built up from the simpler stable binary compounds of the 

 inorganic world, to the more complex and unstable ternary com- 

 pounds of the vegetable world. " In the germination of the 

 plant, a part of the organized molecules runs down into carbonic 

 acid to furnish power for the new arrangement of the other por- 

 tion. ^ In this process no extraneous force is required : the seed 

 contains within itself the power, and the material, for the grow^th 

 of the new plant up to a certain stage of its development. Ger- 

 mination can therefore be carried on in the dark, and indeed the 

 chemical ray which accompanies light retards rather than accele- 

 rates the process." (p. 446.) This important organic principle 

 appears to receive here its earliest enunciation. 



It was also pointed out that on the completion of the cycle of 

 growth (however brief or however extended), the decay of the 

 plant not only returns the elevated matter to its original lower 

 plane, but equally returns the entire amount of heat energy ab- 

 sorbed in its elevation : an amount precisely the same, whether 

 the slow oxidation be continued through a series of years, or a 

 rapid combustion be completed in as many minutes. "The 

 power which is given out in the whole descent is according to 

 the dynamic theory, just equivalent to the power expended by 

 the impulse from the sun in elevating the atoms to the unstable 

 condition of the organic molecules. If this power is given out 

 in the_ form of vibrations of the jetherial medium constituting 

 heat, it will not be appreciable in the ordinary decay say of a 

 tree, extending as it may through several years : but if the pro- 

 cess be rapid, as in the case of combustion of wood, then the 

 same amount of power will be given out in the energetic form 

 of heat of high intensity." 



The elevation of inorganic matter (carbonic acid, water, and 



amount of building energy displayed in the development of the seed 

 under conditions of low and diffused heat : and the expression " Vital 

 Porce" used both by Fowler and Carpenter, was studiously avoided br 

 Heury. ' ' -^ 



113 



