104 HABIT AND INTELLIGENCE. [chap. 



and most interesting confirmation from the effects pro- 

 duced by the vapour of chloroform." ^ 

 Vegetables I have italicised a passage in the foregoing extract, in 

 probably qj-^qj, ^q direct attention to the fact that the motive powers 

 eneig\\ of plants, like those of animals, are subject to the law of 

 exhaustion by exercise and renewal during repose. This 

 appears to afford a presumption, though it would be too 

 much to say that it amounts to proof, that plants, as well 

 as animals, accumulate a store of vital energy which is 

 capable of transformation into motor energy when needed. 

 Eelationof I believe we may consequently state, with very strong 

 organisms probability, that the relation of organisms to energy is 

 and to parallel to their relation to matter. As an organism is 

 constantly acquiring matter, which it transforms by assimi- 

 lation into its own substance, so it is also constantly 

 acquiring energy from the chemical actions that go on 

 within its body, and transforming it into vital energy. 

 Energj- is This process may indeed be called the assimilation of 

 lated ^" ^^icrgy ; — energy, like matter, is transformed by the action 

 of the organism into the peculiar form which the organism 

 needs ; — and this is the definition of assimilation. And 

 as an organism is constantly parting with matter, which 

 undergoes chemical transformation that vtnfits it for con- 

 tinuing any longer to form part of the organism, so it is 

 also constantly parting with energy, which is transformed 

 into inorganic forms (I mean, forms that may exist inde- 

 pendently of vital agency) ; generally into heat or energy 

 of motion : in the case of electric fishes, into electricity ; 

 in the case of luminous insects, into radiance. 



We may consequently make the following general 

 statement. 

 General -^^i organism consists of a mass of peculiar chemical 



statement, compounds of high Complexity, and contains a charge of a 

 peculiar kind of static actual energy. It is constantly 

 transforming both matter and energy, by assimilation, into 

 those peculiar forms : and is as constantly parting with 



1 From a lecture " On Motion in Plants and Animals," delivered at the 

 Eoj'al Institiition on 14tb March, 1862, by William Scovell Savor}', F.E.S. 

 See also Beale's edition of Todd and Bowman's Physiology, pp. 33, 99. 



