THE LA(^HRYMAL GLAND 171 



stain deeply I'ed in Van (Jieson's. Within the interstices of 

 these fibres many nuclear elements are seen which are (a) the 

 nuclei of the endothelium, a rich plexus of arterioles, venules, 

 and capillai-ies which are found in the walls; (b) lymphoid cells, 

 which in \'ery rare instances are so numerous that they obscure 

 the collagenic fibres (I do not consider these lymph cell ac- 

 cunuilations normal as they occur so infrequently) ; (c) occasion- 

 ally solitary nuclei are seen in a cytoplasm which stains yellow 

 in Van Gieson's. The structure of these cells, together with the 

 staining characteristics, suggests that they are smooth muscle 

 cells; (d) plasma cells are also seen. 



In addition to the very small and numerous vessels which 

 accompany and supply the ducts, large vessels and nerves are 

 seen in close proximity to the ducts and following their ramifi- 

 cations to the gland substance. There is no regular distribution 

 of these vessels, so far as numbers are concerned, in relation to 

 the primary ducts. Sometimes only one of these larger arteries 

 is seen in close proximity to a group of primary ducts. Frequently 

 two are seen. Generally one large vein is seen to accompany 

 these ducts. This is true also of the non-medullated nerves. 

 However, much variation is the case with these as well. 



Interlobular ducts. The primary ducts ramify to form the 

 interlobular ducts. These further subdivide to form the intra- 

 lobular ducts. It must be borne in mind, however, that intra- 

 lobular ducts may originate directly from the main or primary' 

 duct. Again practically all of the primary ducts and even the 

 main ducts for some distance are interlobular. Consequently 

 the artificial subdivision of the duct system into primary, inter- 

 lobular, and intralobular ducts must be accepted in a general 

 sense only. In the following description of the interlobular 

 ducts reference is made to those ducts which as a rule result 

 from the ramification of the primary ducts and lie between the 

 lobules. 



The lumina of these interlobular ducts are wide and av(!rage 

 as a rule about one-half to one-fourth the diameter of those of 

 the primary ducts. Here again an explanation is necessary, for 

 the diameters of the former are much larger at their origin than 



