ON ASSIMILATION AND NUTRITION. 



151 



tion of the carbon, and a certain quantity of the hydrog-en, would escape also 

 — leaving behind the remainder of the carbon and the hydrogen, now inca- 

 pable of escape from the want of oxygen to give wings to their flight, to- 

 gether with the residual earth of the animal machine. 



But hydrogen and carbon, though in this case incapable of sublimation 

 for want of oxygen, would still, from their mutual attraction and juxtaposi- 

 tion, enter into a new union and produce a new result, and this result must 

 necessarily be fat ; for fat is nothing else than a combination, in given pro- 

 portions, of carbon and hydrogen. And hence, whatever the respective ani- 

 mal organs of the bodies deposited in these burial caverns may have antece- 

 dently consisted of, whether muscles, ligament, tendon, skin, or cellular sub- 

 stance, when thus deprived of their oxygen and azote, the whole must of ne- 

 cessity be converted into fat. Pure and genuine fat it would have been, pro- 

 vided there had been nothing left behind but mere carbon and hydrogen, and in 

 their respective proportions for the formation of fat ; but as we can scarcely 

 conceive such proportions could take place, or that every corpuscle of the azote 

 could be carried off before the total escape of the oxygen, many parts of it 

 must necessarily have assumed a flaky, soapy, or waxy appearance, from the 

 union of the azote left behind with some portion of the hydrogen, and the 

 consequent production of ammonia or volatile alkali ; since, by an intermix- 

 ture of alkali with fat, every one knows that soap or a saponaceous substance 

 is uniformly produced. 



But, excepting in situations of this kind, in reality, in every situation in 

 which dead animal matter, destitute of its living principle, is exposed to the 

 usual auxiliaries of putrefaction, putrefaction will necessarily ensue, and the 

 balance will be fairly maintained : — the common elements of vital organiza- 

 tion will be set at liberty to commence a new career, and the animal world 

 will restore to the vegetable the whole which it has antecedently derived 

 from it. 



In this manner is it, then, that nature, or rather that the God of nature, is 

 for ever unfolding that simple but beautiful round of action, that circle of 

 eternal motion, in which every link maintains its relative importance, and the 

 happiness of every part flows from the harmony of the whole. Can we, then, 

 do better than conclude with the correct and spirited apostrophe of one of our 

 most celebrated poets 1 — 



, Look round the world I behold the chain of love 

 Combining all below and all above. 

 See plastic nature working to this end ; 

 Atoms to atoms — clods to crystals tend.* 

 See dying vegetables life sustain ; 

 See life, dissolving, vegetate again. — 

 Ail serv'd, all serving, nothing stands alone, 

 The chain holds on, and where it ends unknowa. 



LECTURE XIV. 



ON THE PROCESSES OF ASSIMILATION AND NUTRITION ; AND THE CURIOUS EFFECTS 

 TO WHICH THEY LEAD. 



We have traced out in our preceding studies something of the means by which 

 form, and magnitude, and motion are produced in the inorganized world : — 

 how the various substances that surround us combine and separate, vanish 

 from us and reappear, and, in the multifarious processes they undergo, give rise 

 to new products by new and perpetually shifting involutions. We have far- 

 ther traced an outline of the means by which organized matter is capable of 

 building up the curious structures of plants and animals ; how the chief func- 



• This line is altered to answer the present purpose in a better manner. 



