202 EXPLANATION OF THE PLATES. 



FIG. VI. Diagrammatic representation of the minute 

 structure of a lobule of the liver. 1, Vena portse ; 2, 

 interlobular vein ; 3, capillary network (portal plexus) ; 4, 

 meshes of this network filled with large hepatic cells ; 5, biliary 

 duct; 6, prolongations from this duct terminating in blind 

 extremities ; 7, epithelium of the biliary duct. 



FIG. VII. Cellular elements of the spleen. Splenic 

 cells ; 2, epithelial cells from its blood-vessels. 



Fig. VIII. Thyroid "body (adult). 1, One of its cavities ; 

 2, walls of the cavity composed of connective fibres ; 3, plas- 

 matic cells ; 4, epithelium which has already undergone change. 



PLATE XXIII. 



THE SKIN. 



FIG. I. Section of the skin from the palmar aspect of the 

 last phalanx of the index finger magnified 60 diam. 1, Epi- 

 dermis ; 2, its external or horny layer ; 3, internal layer, or rete 

 mucosum of Malpighi. Beneath the epidermis the true skin, or 

 derma, is represented, also in two layers ; 4, its superficial, 5, its 

 deep layer ; 6, papillae of the derma ; 7, a tactile corpuscle ; 

 8, sweat glands ; 9, excretory duct of sweat glands; 10, adi- 

 pose cells. 



FIG. II. Section of the skin from the palmar surface of 

 the last phalanx of the middle finger. 1, Cells of the horny 

 layer of epidermis destitute of nuclei; 2, polygonal cells of the 

 rete mucosum: 3, oval cells, which always form the deepest 

 layer of the epidermis ; 4, structureless and transparent boun- 

 dary line between epidermis and cutis vera ; 5, plasmatic cells 

 of derma, mingled with connective and elastic fibres ; 6, tactile 

 corpuscle in the interior of a papilla ; 7, the nerve fibre with 

 which it is connected ; 8, branches of this nerve fibre; 9, plas- 

 matic nuclei enveloped by amorphous material. 



FIG. III. Section of the skin from the scrotum. 1, 

 Deep epidermic cells loaded with pigment. 



