[186] for these substances coming together form a combination, but that which is combined is not the less capable of being resolved again into the distinctive qualities from which it was originally formed. For with a sponge saturated with oil it is possible for the water to be taken up and for the wine to be left behind, which may perhaps be because the origin of sponge is derived from water, and therefore it is natural that water being a kindred substance is calculated by nature to be taken up by the sponge out of the combination, but that that substance which is of a different nature, namely the wine, is naturally left behind.