VITALITY 



95 



us try to give an intelligible answer to 

 this question. Water may be raised from 

 the sea-level to a high elevation, and 

 then permitted to descend. In descend- 

 ing it may be made to assume various 

 forms to fall in cascades, to spurt in 

 fountains, to boil in eddies, or to flow 

 tranquilly along a uniform bed. It may, 

 moreover, be caused to set complex 

 machinery in motion, to turn millstones, 

 throw shuttles, work saws and hammers, 

 and drive piles. But every form of 

 power here indicated would be derived 

 from the original power expended in 

 raising the water to the height from which 

 it fell. There is no energy generated by 

 the machinery ; the work performed by 

 the water in descending is merely the 

 parcelling out and distribution of the 

 work expended in raising it. In precisely 

 this sense is all the energy of plants and 

 animals the parcelling out and distribu- 

 tion of a power originally exerted by the 

 sun. In the case of the water, the source 

 of the power consists in the forcible 

 separation of a quantity of the liquid 

 from a low level of the earth's surface 

 and its elevation to a higher position, the 

 power thus expended being returned by 

 the water in its descent. In the case of 

 vital phenomena, the source of power 

 consists in the forcible separation of the 

 atoms of compound substances by the 

 sun. We name the force which draws 

 the water earthward "gravity," and that 

 which draws atoms together " chemical 

 affinity "; but these different names must 

 not mislead us regarding the qualitative 

 identity of the two forces. They are 

 both attractions ; and to the intellect the 

 falling of carbon atoms against oxygen 

 atoms is not more difficult of concep- 

 tion than the falling of water to the 

 earth. 



The building up of the vegetable, then, 

 is effected by the sun, through the reduc- 

 tion of chemical compounds. The phe- 

 nomena of animal life are more or less 

 complicated reversals of these processes 

 of reduction. We eat the vegetable and 

 we breathe the oxygen of the air ; and in 

 our bodies the oxygen, which has been 



lifted from the carbon and hydrogen 

 by the action of the sun, again falls 

 towards them, producing animal heat and 

 developing animal forms. Through the 

 most complicated phenomena of vitality 

 this law runs : the vegetable is pro- 

 duced while a weight rises ; the animal is 

 produced while a weight falls. But the 

 question is not exhausted here. The 

 water employed in our first illustration 

 generates all the motion displayed in its 

 descent, but the form of the motion 

 depends on the character of the machinery 

 interposed in the path of the water. In a 

 similar way the primary action of the 

 sun's rays is qualified by the atoms and 

 molecules among which their energy is 

 distributed. Molecular forces determine 

 the form which the solar energy will 

 assume. In the separation of the carbon 

 and oxygen this energy may be so con- 

 ditioned as to result in one case in the 

 formation of a cabbage and in another 

 case in the formation of an oak. So also, 

 as regards the reunion of the carbon and 

 the oxygen, the molecular machinery 

 through which the combining energy 

 acts may in one case weave the texture 

 of a frog, while in another it may weave 

 the texture of a man. 



The matter of the animal body is that 

 of inorganic nature. There is no sub- 

 stance in the animal tissues which is not 

 primarily derived from the rocks, the 

 water, and the air. Are the forces of 

 organic matter, then, different in kind 

 from those of inorganic matter? The 

 philosophy of the present day negatives 

 the question. It is the compounding, 

 in the organic world, of forces belonging 

 equally to the inorganic that constitutes 

 the mystery and the miracle of vitality. 

 Every portion of every animal body may 

 be reduced to purely inorganic matter. 

 A perfect reversal of this process of 

 reduction would carry us from the inor- 

 ganic to the organic ; and such a reversal 

 is at least conceivable. The tendency, 

 indeed, of modern science is to break 

 down the wall of partition between 

 organic and inorganic, and to reduce 

 both to the operation of forces which 



