114 LIFE AND DEATH. 



energy, as this dogmatic statement would have it 

 supposed. It is only the principle of the final forms. 

 The cycle of energy occasionally terminates in 

 mechanical energy (phenomena of motion) and in 

 a less degree in other energies ; such as, for example, 

 the electrical energy produced by the functional activity 

 of the nerves and muscles in all animals, or in the 

 functional activity of special organs in rays, torpedo- 

 fish, and the malapterurus electricus, or finally, in the 

 photic energy of phosphorescent animals. But these 

 are secondary facts. 



Heat is an Excretuni. — The third principle of bio- 

 logical energetics may be therefore thus enunciated : — 

 Vital energy in its final form becomes thermal energy. 

 This principle teaches us that if chemical energy is 

 the primitive generating form of vital energies, 

 thermal energy is the form of waste, of emunctory, 

 the degraded form as the physicists would say. Heat 

 is in the dynamical order an excretion of animal 

 life, as urea, carbonic acid and water, are excreta in 

 the substantial order. By a false interpretation of 

 the principle of the mechanical equivalence of heat, or 

 through ignorance of Carnot's principle, certain 

 physiologists have fallen into error when they still 

 speak of the transformation of heat into motion or into 

 into electricity in the animal organism. Heat is trans- 

 formed into nothing in the animal organism. It is dis- 

 sipated. Its utility arises not from its energetic value, 

 but from the part it plays as a primer in the chemical 

 reactions, as has been explained with reference to the 

 general characteristics of chemical energy. 



The Effect of Energetics on our Knowledge of the 

 Relations of the Universe. — The consequences of these 

 principles of energetic physiology, which give us so 



