the Fundamental Problem of Nature, 15 



mical and physical forces, although only differently determined ? 

 Suppose that all life on the globe, both animal and vegetable, 

 were to be destroyed and vital force to disappear completely, would 

 the total amount of energy on the globe be diminished ? Would 

 the vital force which disappeared reappear as chemical or as phy- 

 sical force? or would there be a destruction of force? If the 

 former be supposed, then .there is no difference between vital 

 and the other forces of nature further than in the mode of ope- 

 ration. Vital force would in this case simply be the ordinary 

 forces of nature transformed, or, in other words, the ordinary 

 forces differently determined. But if we suppose vital force in 

 itself to be different from other forces irrespective of its mode of 

 operation, and that when it ceases to be vital force it does not 

 become ordinary chemical or physical force, but disappears alto- 

 gether, then the destruction of vital force would involve a viola- 

 tion of the principle of the conservation of energy. If we do 

 not admit a transformation of vital energy, we must assume that 

 when a plant or an animal decays and dies, so many foot-pounds 

 of energy existing in the molecules become extinct. And, on 

 the other hand, when a plant or an animal increases from the 

 embryo state to maturity, so many foot-pounds of energy come 

 into existence. 



Such a view of vital force as this would be diametrically op- 

 posed to the modern science of energy, and wholly untenable. 

 Evidently the vital energies of the plant and animal are derived 

 from the chemical affinities of the food and nutriment which 

 they receive. Vital force is chemical force transformed. The 

 same remark holds true of the mechanical and other physical 

 energies of the body. The energy by which the arm is raised or 

 by which the heart beats is derived from the food. Animal heat 

 is derived from chemical combination. 



So far as all this is concerned, the advocates of the phy- 

 sical theory of life are evidently correct. But are they warranted 

 in affirming, as they do^ that all the energies of plants and ani- 

 mals are either chemical or physical ? Whether such an affir- 

 mation be correct, depends entirely on the idea which may be 

 attached to the terms chemical and physical. If what is meant 

 be that all the energies in organic nature have had a chemical or 

 physical origin, and that there is no energy in nature which has 

 not at one time existed either as chemical or as physical energy, 

 then no one acquainted with the science of energy would for a 

 moment question the correctness of such a conclusion. In this 

 case what is termed vital energy would simply be transformed 

 chemical or transformed physical energy. It would differ from 

 the energies in operation in the chemical and physical worlds 

 only so far as the mode of operation is concerned : the forces 



