94 



HABIT AIND INTELLIGENCE. 



[chap. 



tlieir 

 origin 



is che- 

 mical. 



Does the 

 aBimal 

 organism 

 store 

 energy ? 



Illustra- 

 tion from 

 Arm- 

 strong's 

 Accumu- 

 lator. 



and a few other fishes, have a special apparatus for the 

 production of electricity at will ; the structure of which, 

 according to Professor Owen, very much resembles that of 

 the muscles. 



But motion, light, and electricity, as well as heat, can 

 only be produced by the transformation of pre-existing 

 forms of energy ; and the usual statement is, that all the 

 energy which animals transform and part with is due to 

 the oxidation which, as we have seen, goes on within the 

 organism. This statement however needs modification, for, 

 as we have seen, the organic compounds, which undergo 

 oxidation and decomposition in the organism, are thermo- 

 positive;^ and consequently energy is liberated in their 

 decomposition, which no doubt becomes available for 

 transformation into heat, muscular motive power, or any 

 other form that may be needed for the purposes of the 

 organism. But this we can say with perfect accuracy, 

 that all the energy that animals transform has a chemical 

 source, either in oxidation, or in the decomposition of 

 thermo-positive compounds. 



The question now arises, whether the energy that 

 animals part with in muscular action is obtained, by these 

 chemical actions, at the very moment when it is wanted ; 

 or whether there is a stock of energy constantly kept in 

 the body, in a peculiar form distinct from any chemical 

 form, and capable of being drawn on for conversion into 

 muscular motive power when wanted ? 



This distinction may not be quite intelligible to readers 

 who are not familiar with the subject of the trans- 

 formations of energy ; but it may be illustrated by the 

 following example. "When a steam-engine is at work in 

 the usual way, the motive power that it exerts is all pro- 

 duced, by the combustion of the fuel in the furnace, at the 

 very moment when it is wanted ; and the steam-engine 

 can do no more work in any given time than is due to the 



appear in a steady glow, but in flashes or scintillations, which are produced 

 by irritating the animal ; and some of the smaller Crustacea also emit light 

 in little flashes. (Carpenter's Comparative Physiology, p. 841. )J 

 1 P. 89. 



