126 



SUDORIPAROUS GLANDS. 



[sect. 68. 



latter possess an external covering of indistinctly fibrous con- 

 nective tissue with elongated, scattered nuclei, •which is sharply 

 bounded internally by a delicate membrana propria, and this is 

 lined within with a simple, double or multiple layer of polygonal 

 cells of o , o05" / to o'oo^j'". These cells entirely resemble, in their 

 chemical and other characters, the deeper pavement-epithelial 

 cells, except that they contain some fat-granules, 

 and still more frequently a small number of 

 yellowish or brownish pigment-granules. The 

 B thick walled sudo- 



riparous glandular 

 canals have, in ad- 

 dition to the two 

 coats above de- 

 scribed, a middle 

 layer of longitu- 

 dinal, smooth mus- 

 cular fibres, whose 

 elements are rea- 

 dily separable. In 

 all cases in which 

 the glandular ca- 

 nals contain only fluid, the epithelium is a simple, very distinct 

 layer of polygonal cells of o'oo6'" to o - oi5"'; in the opposite case 

 it can be seen only with difficulty, or not at all. With regard to 

 the occurrence of these two forms of glandular canals, it is found 

 that thick walls and a muscular structure occur especially in the 

 larger glands of the axilla, whose tubes all possess muscular walls, 

 and thence acquire a peculiar striated appearance. A structure in 

 all respects similar I have found only in the large glands at the root 

 of the penis and on the nipple ; although a partially developed or 

 less strongly marked muscular structure undoubtedly exists in some 

 other places, particularly in the glands of the palm of the hand, 

 whose wide canals are remarkable for the thickness of their walls, 

 and present muscular fibres distinctly to be seen, although not so 

 well marked as elsewhere. This remark applies also to particular 

 glands on the scrotum and even on the back, the labia major a, the 

 mons Veneris, and in the neighbourhood of the anus — but with 

 this qualification, that often but a small part of the glandular tube, 

 or even only its ultimate blind extremity is provided with muscular 

 fibres. The glands of the leg, penis, breast (the areola excepted), 

 the eyelid, and the majority of those of the back, the thie;h and 



Sweat ducts, magnified 350 times. A. One with thin walls and a 

 central cavity without a muscular coat from the hand.; a. connective 

 investment; 6. epithelium ; c. cavity. B. A portion of a canal without 

 a cavity, and with a delicate muscular layer from the scrotum ; a. con • 

 nective tissue ; b. muscular layer ; c. cells in the canal with yellow 

 granules in their contents. 



