2 $6 DIGESTIVE ORGANS. [sect. 135. 



with those of the spleen and lymphatic glands, leads us to enquire whether they 

 are not to be ranked with those organs. At any rate, it ought not to be for- 

 gotten that these follicular glands also undoubtedly secrete, and that, accord- 

 ingly, the comparison of them with lymphatic glands (Br'ucke) can certainly 

 not be carried out in all points. The solitary follicles of the large intestine, 

 from which a secretion obviously takes place into the depression situated 

 over them, have, in my opinion, the nearest resemblance to the follicles in 

 question, also the patches of Peyer, which I place in the same rank. 



3.— SALIVARY GLANDS. 



§ J 35- The Salivary Glands, i. e., the parotis, submaxillaris, 

 sublingualis, and the glands of Rivini, agree so fully in their 

 structure with the racemose mucous glands, that a detailed de- 

 scription of them would be superfluous. They are compound 

 racemose glands, and may be considered anatomically as aggre- 

 gations of numerous mucous glands ; that is to say, the lobules 

 of the first and second order correspond, the latter to the entire 

 mucous glands, the former to single lobules of them. The 

 lobules of the second order then unite to form still larger divisions, 

 and a certain number of the latter form the entire gland. The 

 excretory ducts, corresponding in number to the divisions of the 

 gland, are more or less branched, and ultimately present the same 

 conditions at their extremities as those of the mucous glands. 



In intimate composition, likewise, the salivary glands offer little 

 worthy of remark. The acini, in all the three kinds of glands, 

 uniformly measure o"oi6'" to o'024'", or 0-03"' in diameter, are as 

 variously shaped as in the mucous glands, and arise .in a similar 

 manner from the ducts. Their membrana propria is frequently 

 double-contoured, and always covered internally with a pavement 

 epithelium, whose cells, which have but one nucleus, and are 

 o'oos'" to 0*008'" in size, can be obtained in beautiful series by 

 squeezing a gland. In the submaxillary and sublingual glands, 

 these cells constantly contain mucus, also a large number of fat- 

 granules and sometimes pigment-granules ; whilst in those of the 

 parotid the mucus is absent, and even the granular formations are 

 less frequent. In the former, acetic acid renders the contents of 

 the cells turbid, and does not clear them up when added in excess, 

 on which account it cannot be recommended for their investigation, 

 but rather diluted caustic soda, which allows the epithelial cells to 

 be seen in situ. 



The excretory ducts of the salivary glands are lined by a simple 

 layer of cylindrical epithelium, whose cells measure up to o'Oi6'" 



