BY DR. KLEIN. 143 



consists of larger elements, which are coarsely granular, and 

 of polyhedral form, and occasionally contain 3'ellowish-brown 

 pigment. 



As the epithelium elements are often found separated from 

 the membrana propria, it may be inferred that they are much 

 more loosely attached to it than in the other form. Further, 

 it is to be noticed, that the membrana propria contains a con- 

 tinuous longitudinal layer of unstriped muscular fibres, which 

 seem to lie towards its inner surface. Wherever glands of this 

 form occur, they appear to be quite distinct from the others, 

 for no intermediate or transition forms present themselves. 

 It is possible that these glands have a casual relation to the 

 offensive odor of perspiration in certain persons. 



The orifices of the ducts of both kinds of sweat glands are 

 lined with laminated epithelium, which is in direct continuity 

 with the rete Malpighii. The cells of the layer which lies on 

 the propria are of a polyhedral or rather pallisade form. 

 Those which lie next them are somewhat flattened, forming 

 layers which are more and more scanty the further they are 

 from the orifice ; they entirely cease where the duct joins the 

 gland. The membrana propria of the gland itself is lined by 

 a layer of polyhedral cells, which are of uniform size and ap- 

 pearance, and consist of protoplasm. These are readily stained 

 by carmine, and are continuous with the deepest Ia3'er of the 

 epithelium (the pallisade cells). 



Sebaceous Glands. The sebaceous glands consist of closed 

 tubes, which are usually branched, and receive a variable num- 

 ber of tributary sacculi. They either open at the surface, or 

 into hair follicles. In ever}- sebaceous gland the secreting part 

 may be distinguished from the duct. The duct is lined with 

 pavement epithelium, which, when the orifice is at the surface, 

 can be seen to be continuous with the rete Malpighii. In 

 glands which open into hair follicles, it is continuous with the 

 external sheath of the bulb. In passing from the duct to the 

 secreting part, the epithelium changes its character, being re- 

 presented by a layer of granular, cubical, or polyhedral ele- 

 ments which lines the propria. Besides these cells, the sacculi 

 contain larger elements, which are so closely packed together 

 as to be flattened against each other. In fresh preparations 

 these appear to be loaded with fat, but in preparations treated 

 with absolute alcohol and oil of cloves they exhibit a distinct 

 nucleus and investing membrane. The sebaceous glands can 

 be best studied in the skin of mature foetuses, e. gr., in that of 

 the lips and nasal orifice, labia major a, prepuce, and scalp. 

 The acinous form is exemplified in the Meibomian follicles of the 

 eyelids. Sections of these parts hardened in chromic acid must 

 be made, which can be stained and mounted in Dammar var- 

 nish. 



