THE PRINCIPLE OF VITAL AFFINITY. 179 



compounds pre-existing in that fluid ; but that, under the influence of the living 

 solid, transformations or new arrangements of the chemical elements take place, 

 and new compounds are formed. 



In regard to the precise nature, or seat, of some of these transformations, 

 there is considerable difficulty, but we are at present concerned only with the 

 principle ; and may state in illustration of it, two cases of transformation, of 

 which there is no doubt, the change from carbonic acid and water to starch in the 

 cells of plants (oxygen escaping), and the change from starch to fat in the cells 

 of animals (carbonic acid and water escaping). And that I am correct in asserting 

 that the organ which exercises this and other chemical powers in living plants is 

 not only of the simplest construction, but of uniform construction, while the pro- 

 ducts of its action are very various, will appear from the following statement by 



MULDEK. 



" Pure cellulose is easily obtained from the pith of the elder-tree, from very 

 young roots, and from other young parts of plants. From these parts it is pre- 

 pared by digesting them, after being minutely divided, with alcohol, ether, di- 

 luted potash, hydrochloric acid, and water. In this manner, the starch, gum, 

 fats, resins, vegetable alkalis, salts, sugar, — and at the same time the peculiar 

 woody matter are separated." 



" After the action of these solvents, and especially of the alkali, the cellulose, 

 which was formerly solid and dense, appears in a spongy form. We may state 

 as a fact, that the proper tissue of all plants which have been previously exposed 

 to the influence of these solvents, leaves a substance luhich is identical in all of 

 them, a substance which contains carbon and the elements of water." — (Chemistry 

 of Vegetable and Animal Physiology, pp. 188-195.) 



Mulder annexes to this statement a speculation in regard to the influence 

 of forms in organized bodies, as affecting their chemical powers or properties, 

 which, so far as I can understand it, I think fitted to convey an erroneous im- 

 pression. 



" One of the first and chief laws visible in organic nature is, that the form 

 has as much influence on the character of the phenomena as the substance of 

 which that form consists. The effects of the primary forces existing in the 

 molecules, have become, by the combination of elements into hollow globules, 

 altogether peculiar." 



" In organic nature, besides all the peculiarities existing in the carbon, hy- 

 drogen, and oxygen, we must suppose, as a chief consequence of this, a tendency 

 to form membranaceous, concave, spherical little bodies, in which, because of this 

 form, new peculiar properties manifest themselves, which cannot be brought out 

 by other forms. Thus, by matter and form, all that we observe in nature is, to 

 a great extent determined." — {Ibid., p. 189.) If by this it is meant that the acqui- 

 sition of the form is the physical cause of the existence of the properties which 

 cells, or any other organized structures present in the living state, two questions 



