398 MYSTERIES OF LIFE. 



has already been shown to act in producing combination 

 between gases; but of this we have no proof. We 

 know that electricity is capable of producing the 

 required conditions, and we also learn, from the beau- 

 tiful researches of Faraday, that the quantity of elec- 

 tricity developed during decomposition is exactly equal 

 to that required to effect the combination of the same 

 elements. Thus it is quite clear that, during the com- 

 bination of the carbon of the blood with the oxygen of 

 the air, a large amount of electricity must become 

 latent in the compound. The source of this we know 

 not : it may be derived from some secret spring within 

 the living structure, or it may be gathered from the 

 matter surrounding it. There is much in nervous exci- 

 tation which appears like electrical phenomena, and 

 attempts have been frequently made to refer sensation 

 to the agency of electricity. But these are the dreams 

 of the ingenious, for which there is but little waking 

 reality. 



Every mechanical movement of the body occasions 

 the development of heat ; every exertion of the muscles 

 produces sensible warmth ; and, indeed, it can be shown 

 by experiment that every expansion of muscular fibre is 

 attended with the escape of caloric, and its contraction 

 with the absorption of it. There are few operations of 

 the mind which do not excite the latent caloric of the 

 body, and frequently we find it manifested in a very re- 

 markable manner by a suddenly-awakened feeling. The 

 poet, in the pleasure of creation, glows with the ardour 

 of his mind, and the blush of the innocent is but the 

 exhibition of the phenomenon under some nervous ex- 

 citation, produced by a spirit-disturbing thought. Thus 

 we see that the processes of digestion and respiration 

 are not the only sources of animal heat, but that many 

 others exist to which much of the natural temperature 

 of the body must be referred. 



So much that is mysterious belongs to the phenomena 



