212 Comparative Physiology. 



vegetables are, in the living state of these fluids, the appro- 

 priate stimulus to the assimilating and organising power, which 

 in each tissue converts the nutritious matter into a structure 

 like its own ; but the same materials, not themselves endowed 

 with vital properties, would be totally inert. Every tissue 

 possesses vital properties peculiarly its own, besides that com- 

 mon to all, and each ]3roperty of each organ has stimuli appro- 

 priate to itself." 



It is impossible in a condensed view to do sufhcient justice 

 to so difficult a subject ; by those interested in such abstract dis- 

 quisitions, recourse must be had to the work itself, which will 

 amply repay the trouble. On the same subject DeCandoUe re- 

 marks, that there are four forces in nature, attraction, affinity, 

 (or chemical force), and also vital and intellectual force. It is 

 difficult, he says, to divine what is chemical and what vital, 

 and to say whether vitality is owing to the form of the organ, 

 or the form of the organs to vitality. Cuvier says form is essen- 

 tial to life. Life is opposed, he says, to chemical affinity, and 

 is a mysterious power, capable of uniting molecules in a way 

 which no other power can. Miiller compares life to an idea, 

 or instinct, forming a pattern to which the organism is made to 

 conform, and calls it a principle. The simple germinal disc he 

 regards as the potential whole of the futiu*e being. The or- 

 ganised state is the result of the organic creative power, and 

 organic matter. Whether the two have ever been separated is 

 not, he says, an object of science. Schleiden says form is the 

 result of vitality, and not vitality of form. It is not necessary 

 to suppose life a separate psychological being ; the term prin- 

 ciple does not necessarily imply this supposition. Dr. Carpenter 

 says, it is unphilosophical to su2:)pose that the Creator first gave 

 existence to a vital principle or organic agent, and then set it to 

 work in organising the body, since every organised structure is 

 capable of exhibiting life when the appropriate stimuli are 

 applied, so long as it retains the constitution which causes it to 

 possess those properties. It is unnecessary, however, to set 

 limits as to time to creative power ; when the molecules were 

 arranged in proper order, we are told God infused into them 

 the breath of life : this life may have existed before, or may 

 have then been created on purpose, for any thing we know, or are 

 likely ever to know. We may call it a property of organised 

 beings, or a principle ; or we may confound the two together, 

 by the manner we talk of them. Life and organisation are so 

 inseparably connected that we can hardly think of them as 

 separate. We know not yet whether attraction is a property 

 or a principle ; though, from increasing as the mass increases, 

 it has been called a property, it may be a principle, for aught 

 we can tell, which produces the attractive projaerties, and may 



