360 



SECRETION. 



with an external layer of inelastic and small elastic fibres, and are lined by cells. Next 

 the membrane, the cells are polyhedric, pale, and granular, most of them presenting a 

 nucleus and a nucleolus ; but the follicle itself contains fatty granules and the other con- 

 stituents of the sebaceous matter, with cells filled with fatty particles. These cells 

 abound in the sebaceous matter as it is discharged from the duct. The great quantity of 

 fatty granules and globules found in the ducts and follicles of the sebaceous glands ren- 

 ders them dark and opaque when examined with the microscope by transmitted light, 

 and their appearance is quite distinctive. The larger glands are surrounded with capil- 

 lary blood-vessels. The glands which open into the larger hair-follicles will be illus- 

 trated in connection with the anatomy of the hairs. 



The ceruminous glands of the ear produce a secretion resembling the sebaceous mat- 

 ter in many regards, but in their anatomy they are almost identical with the sudoripa- 

 rous glands. They belong to the variety of glands called tubular, and they consist of a 

 nearly straight tube which penetrates the skin and a rounded or ovoid coil situated in the 

 subcutaneous structure. These glands are found only in the cartilaginous portion of the 

 external meatus, where they exist in great numbers. They are rather more numerous in 

 the inner than in the outer half of the meatus. 



The ducts of the ceruminous glands are short and nearly straight, simply penetrating 

 the different layers of the skin, and are from y^ to ^ 7 of an inch in diameter. Their 

 openings are rounded and about ^fg- of an inch in diameter. They sometimes terminate 

 in the upper part of one of the hair-follicles. They present an external coat of white 

 fibrous tissue and are lined with several layers of small, pale, nucleated epithelial cells. 



i& a& 



FIG. 100. Ceruminous glands. (Sappey.) 



Vertical section of the skin of the external auditory meatus: 1, 1, epidermis; 2, 2, derma; 3, 3, series of hair-follicles 

 lodged in the substance of the skin ; 4, 4, series of sebaceous glands attached to these follicles ; 5, 5, subcutaneous 

 areolar layer ; 6, 6, ceruminous glands ; 7, 7, ceruminous glands with the ducts divided ; 8, 8, adipose vesicles. 



The glandular coil is an ovoid or rounded, brownish mass, from T |- 7 to -^ or $ of 

 an inch in diameter. It is simply a convoluted tube, continuous with the excretory duct 

 and terminating in a somewhat dilated, rounded extremity. It presents, occasionally, 

 small, lateral protrusions. The diameter of the tube is from -3-^ to -^^ of an inch. It 

 possesses a fibrous coat, with a longitudinal layer of involuntary muscular fibres, and 

 externally a few elastic fibres. It is lined by a single layer of irregularly polygonal cells, 

 which are from to - of an inch in diameter. These cells contain numerous 



