70 165 Drawing of a magnified section through the skin of the palmar surface of the thumb, including three of the ridges seen on that surface. _a_, the outer or horny layer of the _cuticle_; _b_, the deeper layer of the same called “_rete mucosum_;” _c_, _c_, _c_, the _cutis_, with _papillæ_ rising from its surface beneath the ridges and projecting into the rete mucosum; _g_, _g_, grains of _fat_ lying in the deeper part of the cutis and in the tissue beneath it. Between _f_ and _f_ are three _sweat-glands_, each composed of a tube rolled up into a ball or knot. The tubes (_h_, _h_) are seen ascending from them through the cutis and cuticle, and opening at the tops of the ridges. (From Kölliker’s _Mikroskopishe Anatomie_.) 71 170 Section of skin still more magnified. _a_, Outer or horny stratum of cuticle; _b_, inner stratum of cuticle, or “rete mucosum;” _c_, papillary stratum of cutis; _d_, deeper or fibrous stratum of cutis. The curling tube rolled into a ball at the lower part is the sweat-gland. Its duct is seen ascending through the fibrous structure of the cutis, and presents the coiled appearance of a rope as it traverses the cuticle. 72 170 A few layers of the cuticle and rete mucosum of a Negro, showing the spots of dark pigment in the rete which give the black colour to the Negro’s skin. (This and the preceding from Todd and Bowman’s _Phys. Anatomy_.) 73 170 Section of a Corn and adjacent skin. _a_, the _cuticle_; _c_, the _cutis_ with its _papillæ_. The cuticle is seen to be very thick, and the papillæ are somewhat enlarged in the corn. 74 170 Section of a Wart and adjacent skin. _a_, _cuticle_; _c_, the _cutis_ with its _papillæ_. The latter are seen to be enlarged, or “hypertrophied,” in the wart. 75 174 Vertical section, made lengthways, of a Nail raised from its bed, showing its connexion with the cuticle. _a_, _a_, _cuticle_; _d_, _d_, _nail_. 76 174 Similar section of a Nail lying in its bed of cutis. _a_, _cuticle_; _b_, _rete mucosum_; _c_, _cutis_; _d_, _nail_. 77 174 Section of the Cutis from which the nail, the cuticle, and the rete have been removed.