This continual destruction of the epidermis has not sufficiently arrested the attention of physiologists. The following are the proofs of its reality; 1st, if with the blade of a knife, we scrape strongly its external surface, a large quantity of powder is removed which sulphuric acid easily dissolves, and which is greyish. The epidermis whitens a little in this place, then resumes its colour, especially if it is moistened. By scraping again, we do not remove any more powder, it is necessary in order to obtain it, to wait twelve or twenty hours. 2d. This substance becomes superabundant, when the skin has not been washed for a long time. Hence why those who soak their feet that have not been cleaned for a long time, detach so great a quantity of it. It is especially on the sole of the foot that this substance is formed in abundance. We often observe in dead bodies that it forms almost a layer in addition to the epidermis, but which is very distinct from it, and can be removed with ease. I attribute this circumstance to the thickness which the epidermis has in this place. We should no doubt find as much upon the hand, were it not for the continual friction of this part. We see it often on the patients in hospitals, after remaining a long time in bed without having been cleansed. Water naturally removes this substance, that is produced by the destruction of the epidermis, and, which, mixing with the residue of transpiration, that the air cannot carry off by evaporation, renders bathing, as I have observed, a natural want. Though it may be neither exhaled nor absorbed, and though its production may appear to be owing to mechanical friction, yet we can, in its relation, consider the epidermis as an emunctory of the body, since it is renewed by a substance coming from the dermis, as fast as it is removed. It is evident, as the epidermis has no vital properties, that it cannot be the seat of any kind of sympathies, which are aberrations of these properties. Hence its life is extremely obscure, I doubt even if it possesses vitality. We might almost say that it is a semi-organized body, inorganic even, which nature has placed between external inanimate bodies and the dermis, which is completely organized, in order to assist their passage and guard against their force.