The first, which relates to the nutritive nature of this matter, is in part resolved by the reasons we have already given, and will be fully demonstrated in the succeeding chapter. We will shew that there exists an infinity of living organic particles in Nature; that their production is of little expence to Nature, since their existence is constant and invariable, and that the causes of death only separate without destroying them. Therefore the matter which the animal or vegetable assimilates is an organic matter of the same nature as the animal or vegetable itself, and which consequently can augment the size without changing the form or quality of the matter of the mould, since it is in fact of the same form and quality as that which it is constituted with. Thus, in the quantity of aliments which the animal takes to support life, and to keep its organs in play, and in the sap, which the vegetable takes up by its roots and leaves, there is a great part thrown off by transpiration, secretion, and other excretory modes, and only a small portion retained for the nourishment of the parts and their expansion. It is very probable, that in the body of an animal or vegetable there is formed a separation of the brute particles of the aliments and the organic; that the first are carried off by the causes just mentioned; that only organic particles remain, and that the distribution of them is made by means of some active power which conducts them to every part in an exact proportion, insomuch that neither receive more or less than is needful for its equal nutrition, growth, or expansion.