147 



Glands of the general surface. 



In addition to the openings seen along the lateral line and visible 

 to the naked eye, the general surface, as before stated, is studded 

 with other openings of a similar character, but so much smaller as to 

 become visible only to the assisted sight. The diameter of these 

 openings is about -^ of an inch, and nearly uniform throughout. 

 They are rounded or oval; have their margins sharply defined, 

 slightly elevated above the surface and surrounded by thickly set gra- 

 nules of pigment. In a vertical section of the skin, examined by 

 transmitted light, membranous tubes are seen to proceed onwards 

 from these openings to the subcutaneous filamentous tissue in which 

 they terminate. The physical properties of this latter tissue offer a 

 striking contrast to those of the skin proper. The latter is hard and 

 dense, and thin sections may readily be made to transmit the light: 

 the former is loose, soft, oily, of a dead white colour when com- 

 pressed, and under all circumstances transmits the light with diffi- 

 culty. Demonstration of the mode of termination of these tubes, 

 therefore, is attended with considerable difficulty ; and even when ef- 

 fected, is more the result of chance than of any peculiarities in the 

 means employed. Under favourable circumstances, however, the ter- 

 mination of these tubes may be very distinctly made out. It will then 

 be seen that they end in little saccular dilatations, more or less con- 

 tracted at different points, as if the cavity were subdivided into com- 

 partments by imperfectly developed membranous septa. These tubes 

 and their saccular terminations were generally filled with small oil- 

 globules, which, by manipulation of the glasses, might be made to ap- 

 pear at the mouths of the follicles on the free surface of the skin. It 

 was almost impossible to determine the exact structure of the parietes 

 of these follicles, on account of the great diffraction of light produced 

 by the oily matter in their interior, from which they could not be freed. 

 Two sorts of fibrous tissue appeared to enter into the composition of 

 their walls, — the one external, loose, reticulated, and connected with 

 the subcutaneous filamentous tissue, and the other an internal or 

 fibrous, coat proper, composed of distinct translucent fibres, marked by 

 the presence of atrophied nuclei, and resisting the action of acetic 

 acid. The inner surface of this latter tunic was very glistening, and 

 appeared marked in various ways by horizontal and cross lines. These 

 markings, though in some parts regular, I could not safely refer to a 

 cellular origin. The saccular terminations of these follicles were each 



