SECT. 74.] 



SEBACEOUS GLANDS. 



J 37 



Fig. 61. 



J 



or flask-shaped, or even elongated and tubular. Their size varies 

 extremely,, from o - o6'" to o - i6"' in length, o , o2'" to o*i'" in 

 breadth ; it amounts, on an average, in the round ones, to 0"04'", 

 and in the others to o - o8'" in length, and 0*03'" in breadth. Their 

 excretorv ducts are likewise of verv various dimensions — long or 

 short, wide or narrow ; the principal excretory ducts measure in 

 the nose and labia minora up to +'" in length, -^~" to \'" in 

 breadth, and possess an epithelium Q'Ois'" to 0"03'" thick. 



The Meibomian glands of the eyelids, whose description will be 

 given with that of the eye, resemble the sebaceous glands in all 

 essential points, except that they are larger. 



§ 74. The minute structure of the sebaceous glands is as follows. 

 Everv gland has an outer delicate envelope of connective tissue, 

 which proceeds from the hair-follicle, or in the case of independent 

 glands, from the coriurn ; within are masses of cells, which are 

 continued from the outer root-sheath of the hair-follicle, and 

 form a lining of round- 

 ed or polygonal, nu- 

 cleated cells, disposed 

 iu several (2 to 6) 

 layers. In the glan- 

 dular saccules them- 

 selves, these cells ge- 

 nerally contain a little 

 fat, and form a simple 

 layer, but gradually 

 pass iuto cells which 



A. A glandular vesicle of an ordinary sebaceous gland, magnified 

 loiirlcSS fat that theV 250 times, a. Epithelium sharply defined, but -without being in- 



J vested by a membrana propria, and passing continuously into the 

 mi°"llt be fltlv termed fat-cells in the interior of the gland-tube (the contents are rather 

 • indistinctly represented). B. Sebaceous cells from the gland-tubes, 



SebaceOUS Cells (fi°\ 6l\ an( * the sebaceous matter, magnified 350 times, a. Smaller nu- 

 V. »! /' c i e ated cells, containing but little fat, and possessing more the cha- 

 Tlieirfat aDDeai'S either racter of epithelium ; 6. cells abounding in fat, without visible nuclei; 

 "1 c. cells, in which the fat-particles are beginning to run together; 



in the form of Small d - cel1 writl1 one fat-drop; e. /., cells whose fat has partly dis- 

 appeared. 



discrete drops (b &), or, 



as is more common, in larger drops (c) ; in many cells, indeed, 

 there are only a few, or even but one single drop entirely filling 

 them, so that they offer a great resemblance to fat-cells of the 

 panniculus adiposus. If these innermost cells, in which nuclei 

 can be but rarely discovered, be followed towards the excretory 

 ducts, nothing is easier than to observe that similar cells, in unin- 

 terrupted succession, are continued into the ducts — that is, into 



