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trition, that is not yet completely determined. A limb that is para- 

 lized, by the division or tying of its nerves, or by any other affection, some- 

 times retains its original size and plumpness ; most frequently, however, 

 though perhaps for want of motion, it becomes parched, emaciated, and 

 skrinks in a remarkable degree. 



CIX. We should be enabled to understand the process of nutrition, if 

 after having accurately determined the difference of composition between 

 our food, and the substance itself of our organs, we could see how each 

 function robs the aliments of their qualities, to assimilate them to our 

 own bodies; and what share each function takes in the transmutation of 

 the nutritive particles into our own substance. To illustrate this point, 

 suppose a man to live exclusively on vegetable substances, which, in fact, 

 form the basis of our food ; on whatever part of the plant he may live, 

 whether on the stem, on the leaves, on the blossoms, on the seeds, or on 

 the root; carbon, hydrogen, and oxygen enter into the composition of 

 these vegetable substances, which, by a complete analysis, may all be 

 resolved into water and carbonic acid. To these three constituent prin- 

 ciples, there is frequently united a small quantity of azote, of salts, and 

 of other materials, in different proportions. If then, we examine the na- 

 ture of the organs in this man whose food is entirely vegetable, it will be 

 found that they are different in their composition, and t'ar more animal- 

 ized than that kind of food; that azote predominates, though the vegeta- 

 ble substance contains none or only a very small quantity, that new pro- 

 ducts, undistinguishable in the aliments, exist, in considerable quantity, 

 in the body which is fed on them, and appear produced by the very act 

 of nutrition. 



The essence of this function is, therefore, to make the nutritive matter 

 undergo a more advanced state of composition, to deprive it of a portion 

 of its carbon and of its hydrogen, to make azote predominate, and to 

 produce several substances, which did not exist in it before. All living 

 bodies seem to possess the faculty of composing and decomposing the 

 substances by means of which they are maintained, and to form new pro- 

 ducts: but they possess it, in various degrees of energy. The sea-weed, 

 from the ashes of which soda is obtained, on being sown in a box of soil, 

 in which there is not a single particle of that alkali, and watered with 

 distilled water, will for a time continue to form it, as if it had grown 

 on the sea-shore, in the midst of marshes constantly inundated by salt 

 and brackish water. 



Living bodies then, are real laboratories, in which are carried on 

 combinations and decompositions which art cannot imitate ; bodies that 

 appear to us simple, as soda and silex, seem to be formed by the union 

 of their constituent particles: while other bodies, whose composition we do 

 not understand, undergo an irresistible decomposition : hence, one may 

 infer, that the power of Nature in the composition and decomposition of 

 bodies, far exceeds that of chemistry*. 



Straw and cereal plants contain an enormous quantity of silex, even 

 when the earth in which they grow bus been carei'ully deprived of its si- 

 liceous particles. Oats, particularly, contain a considerable quantity of 

 that verifiable earth ; the ashes obtained by burning its seed, on being 



* To the substances compounded by the animal body may be added lime, which is 

 formed in quantities far exceeding the amount taken in with the food. Godman. 



2 F 



