170 



JOHN SUNDWALL 



Goblet cells are also seen in the primary ducts. They are 

 not so numerous by any means as in the main ducts. Many 

 transverse sections of the former may show none of these cells 

 while others again may show from one to three. Their staining 

 characteristics are similar to those described for these cells in 

 the main ducts (figs. 9 and 10). 



The epithelial cells of primary ducts border on a more or less 

 indefinite basal membrane, which stains a deep blue in Mallory's 

 stain, and is derived from and is a condensation of the circular 

 layer of collagenic fibres which surround the epithelium and 

 form the duct wall. The average thickness of this connective 



Fig. 9 Epithcliviin of i)riiiiarv duct, cross section. Zeiss, oc. 4, obj. S mm. .4, 

 goblet cell. 



Fig. 10 Epithelium of primary duct. Enlarged drawing, Zeiss, oc. 4, obj. 

 2 mm. oil. ^4. cement lines. 



tissue wall is 50 to 100/x. Its outer borders are gradually lost 

 in the general connective tissue septa of the gland, which are 

 always more abundant where these ducts are found. Long fine 

 interlacing elastic fibres are present throughout the entire thick- 

 ness of this circular connective tissue coat. Immediately sur- 

 rounding the basement membrane these fibres form a closely 

 interlacing layer similar to that described for the large main 

 ducts. As the ducts become smaller, through ramification, 

 there is a gradual decrease of these fibres and in some of the 

 smaller primary ducts they are difficult to make out. 



The chief component of the circular connective tissue wall is 

 the collagenic or white fibrous tissue. The collagenic fibres 



