304 THE ANIMAL AS A PRIME MOVER. 



As remarked by Professor Foster, 1 "from many considerations it is 

 extremely probable that a chemical change — an explosive decomposi- 

 tion of more complex into more simple substances — is the basis of a 

 nervous impulse." The energy thus developed is largely in this case 

 employed in conveying the impulse along the nerve and in setting up 

 muscular or mental evolutions and applications of energy at its 

 extremity. 



The introduction of chemical actions in the production of solution of 

 the available constituents of the food is one of the essential elements 

 of the extraordinarily perfect utilization of all its substance, of its 

 complete digestion, entire absorption, and thorough assimilation. Only 

 from a state of solution could complete absorption or precipitation take 

 place. Food undergoes "profound disruption" before it can become a 

 part of the body or furnish it energy. " It would almost seem that the 

 qualities of each particle of living protoplasm were of such an indi- 

 vidual character that it had to be built up afresh from almost the very 

 beginning." 2 



The presence of considerable quantities of phosphorus, especially in 

 the nervous system of the auimal, indicates that chemical actions may 

 be very rapid, and possibly may especially indicate the resultant pro- 

 duction of peculiar material and nonmaterial output, as the electric 

 current of the gymnotus, if not all animals, light in the firefly, the vital 

 forces of all vital machines. The presence of water in large quantity 

 points the same way. 



The blood is the carrier and distributor of all potential energy from 

 the dissolved material of supply, and the capacity of the blood vessels 

 is probably something of a gauge of the quantity of energy supplied 

 the parts to which they lead, and of the mean rate of expenditure dur- 

 ing their period of operation aud restoration to normal condition of 

 rest. Whether the nutriment and the potential energy thus conveyed 

 supply energy directly, as supposed by Dr. Pavy and others, 1 ' or indi- 

 rectly by the upbuilding of tissue later broken down and supplying 

 directly the stock of energy needed for transformation, as supposed 

 and probably experimentally proven by Dr. Flint, 4 the result is the 

 same. 



The influence of the form in which the potential energy is supplied 

 the machine is well exhibited where, as in penal institutions like that 

 of the State of New York, "experimental classes can be formed and 

 the effect of the changes thus. found practicable observed and meas- 

 ured." The inverse ratio of food supply to crime and to illness had long 

 been recognized by students in anthropology aud sociology; the fact 

 that every variation of the quality of an ample food supply produces 



1 Encyclopaedia Britannica. Article, Physiology, p. 21. 



8 Ibid. 



:i The Lancet, Nov. 25, 1876. 



4 Journal of Anatomy and Physiology, Oct., 1877, 



