DEFINITIONS. 183 



cause, or, in other words, whether .there may not be se- 

 veral mediate causes between it and the Primary Cause, 

 are. questions to the solution of which we are totally in- 

 competent. Like gravity and electricity, we know life only 

 by its effects, or. rather we are acquainted with tlie three 

 only as so many names given to certain combinations of 

 effects. The particular combination or series of effects 

 which we call life, differs from gravity or electricity in the 

 circumstance that these effects are totally different from 

 each other. They however all concur to the same object, 

 namely, the preservation of the individual and of the spe- 

 cies. We observe however that during life, organic bodies 

 can resist most of those chemical and more general laws 

 which govern inorganic matter, and can modify the inert 

 properties of this by an apparatus of organs specially con- 

 structed for the purpose. And on the whole we con- 

 clude that it is not a being enjoying a distinct existence, 

 but an adherent quality which must necessarily havei^ 

 subject. It is a motive quality of matter hke gravity, 

 and without matter for its subject we have no reason to 

 suppose that it can exist. It is to the organic body what 

 the expansion of steel is to a watch, or that of steam is 

 to the engine ; but if we ask what is expansion ? what is 

 life? we can get no answer but a recital of their effects. 



21. The slightest study of the different systems of gene- 

 ration among the lower animals will show how erroneous 

 is the notion of those who would consider the life of each 

 organized body as a distinct immaterial being, superadded 

 to its material structure. The most minute embryo or 

 germ enjoys a vegetative Ufe while attached to its parent 

 stock, yet every experiment proves that it has as yet no 



