We see upon the epidermis the same wrinkles as upon the skin, because being exactly contiguous, both wrinkle at the same time. Different pores open on its surface after having passed through it. Some transmit the hairs; these are the most apparent; others give passage to the exhalants. We do not see these in the natural state, because their course is oblique, and they open between two small layers, which, being in contact with each other when we do not sweat, conceal their termination. But if, the skin being very dry, we suddenly sweat, as after drinking tea, then the little drops which escape from the whole cutaneous surface, not having had time to run together, but remaining separate, we see, by the places where they are, the orifice of the exhalants. Besides, if we examine against the light a considerable portion of epidermis, its transparency allows us to see many small pores separated from each other by interstices, and which pass through it in an oblique direction. It is only in the soles of the feet and the palms of the hands that we cannot make this observation, which is owing to the thickness in those parts. It is impossible to distinguish in these pores the absorbent orifices from those of the exhalants, even when mercury enters the first by friction. The internal surface of the epidermis adheres very closely to the skin. The means of union are at first the exhalants, the absorbents and the hairs, which in passing through the first, adhere to it more or less, and thus fix it to the second, from which they arise. By separating the epidermis by maceration, which is the most proper means, we see on its internal surface many small elongations of greater or less length, and which, when examined attentively, appear to be nothing but the broken extremities of exhalants and absorbents. In fact these little elongations which are easily raised up, and which then appear like small ends of thread when they are of some size, but which exhibit only inequalities when they are left very short, have all of them an oblique course, and terminate in the pores which, we have said, pass through the epidermis to go to its surface. Their existence is sufficient, at the first inspection and without the aid of a microscope, to enable us to distinguish the internal from the external face of this membrane. The spaces that separate them are more or less large. About these spaces, the adhesions are less. It is at this place that the small epidermoid vesicles are formed with which the skin is covered when plunged into boiling water. The depressed interstices, which separate these vesicles, are the places where the exhalants are and which have prevented the epidermis from being raised up. When ebullition is long continued, they are detached also.