A second resemblance may be drawn from the expansion of their parts, a property which is common to both; for vegetables grow as well as animals, and if the manner in which they expand is different, it is not totally nor essentially so, since there are very considerable parts in animals, as the bones, the hair, the nails, the horns, &c. whose expansion is a perfect and real vegetation; and the foetus, at its first formation, may be said rather to vegetate than live. A third resemblance arises from there being some animals which propagate like plants, and by the same method. The multiplication of the vine-fretter, which is made without copulation, is like that of plants by seeds; and that of polypuses, by cutting them, resembles the multiplication of trees by slips. We can then assert with greater foundation, that animals and vegetables are beings of the same order, and that nature passes from one to the other by insensible links; since the properties wherein they resemble each other are general and essential, and those on which they differ confined and particular. If we compare animals and vegetables by other lights, for example, by number, situation, size, form, &c. we shall draw fresh inductions from them. The number of the animal species is much greater than that of plants. In the class of insects alone there are a greater number of species than there are kinds of plants on the surface of the earth. Animals likewise much less resemble each other than plants; and it is this resemblance among the latter which makes the difficulty of knowing and discerning them, and has given rise to so many botanical systems; and it is for this reason that more labour has been bestowed on that than on zoology.