EXPLANATION OF THE PLATES. 203 



FIG. IV. Transverse section of a papilla of the true 

 skin. 1, True skin ; 2, its limitary border ; 3, epidermis. 



PLATE XXIV. 



NAILS AND HAIK. 



FIG. I. Transverse section of a nail near its root 



magnified 6 diam. 1, The true skin, forming the matrix of the 

 nail ; 2, rete mucosum / 3, epidermic structure of the nail ; 4, 

 fold of true skin in which the root and sides of the nail are 

 received ; 5, surface of this fold continuous with the matrix ; 

 6, rete mucosum of neighboring skin, continuous with that of 

 the nail ; 7, line of junction of the epidermis of the neighbor- 

 ing integument with the epidermic layer of the nail. 



FIG. II. The same section magnified 25 diam. 1, Papillae 

 of true skin forming matrix of the nail ; 2, rete mucosum of 

 nail; 3, its epidermic layer; 4, line of junction of epidermis 

 of neighboring skin with that forming the nail ; 5, the only 

 locality at which they are truly continuous : 6, true skin, with 

 its papillae, of the fold, or groove, lodging the roots and sides 

 of the nail ; 7, rete mucosum ; 8, papillae of the derma in trans- 

 verse section ; 9, sweat duct ; 10, epidermis. 



FIG. III. Longitudinal section of a nail magnified 6 

 diam. 1, Nail ; 2, derma ; 3, epidermis. 



FIG. IV. A hair from the scrotum in its follicle, with a 

 sebaceous gland magnified 50 diam. 1, lower part of the 

 shaft of the hair ; 2, its root ; 3, its bulb ; 4, epidermis of the hair; 

 5, its cortical substance ; 6, its medullary canal ; 7, papilla of the 

 bulb ; 8, true skin forming wall of the hair follicle; 9, exterior 

 epidermic layer; 10, interior epidermic layer; 11, sebaceous 

 gland; 12, its excretory duct. 



FIG. V. Imbrication of the cells forming the epidermic 

 layer of the hair. 



FIG. VI. Cells from the same layer detached and treated 

 by acetic acid. 



