OF ORGANIC NATURE. V 



but considering the subject before us, such a course 

 would not be that best calculated to assist us. In an 

 argument of this kind we must go further and dig 

 deeper into the matter; we must endeavour to look 

 into the foundations of living Nature, if I may so say, 

 and discover the principles involved in some of her 

 most secret operations. I propose, therefore, in the 

 first place, to take some ordinary animal with which 

 you are all familiar, and, by easily comprehensible and. 

 obvious examples drawn from it, to show what are the 

 kind of problems which living beings in general lay 

 before us ; and I shall then show vou that the same 

 problems are laid open to us by all kinds of living 

 beings. But, first, let me say in what sense I have 

 used the words " organic nature." In speaking of the 

 causes which lead to our present knowledge of organic 

 nature, I have used it almost as an equivalent of the 

 word " living," and for this reason, — that in almost all 

 living beings you can distinguish several distinct por- 

 tions set apart to do particular things and work in a 

 particular way. These are termed " organs," and the 

 whole together is called " organic." And as it is 

 universally characteristic of them, this term " organic " 

 has been very conveniently employed to denote the 

 whole of living nature, — the whole of the plant world, 

 and the whole of the animal world. 



Few animals can be more familiar to you than that 

 whose skeleton is shown on this diagram. You need 

 not bother yourselves with this " Equus caballus " 

 written under it ; that is only the Latin name of it, 

 and does not make it any better. It simply means the 

 common Horse. Suppose we wish to understand all 

 about the Horse. Our first object must be to study 

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