THE LACHRYMAL GLAND 217 



Fixed and staified preparations 



Se('i'(>ti()ii (':ii)illaries are readily seen in tissues stain(Hl with 

 the s(Mi)us granule stains already named (figs. 18 and 19). Here 

 the\' are seen as intercellular structures and are outlined by a 

 thin deeply stained cement substance. These sections plainly 

 show that the secretion capillaries are much modified by the 

 stages of granule formation within the cells. If bordering cells 

 are in a maximum stage the capillaries are not seen, only the 

 cement line projects downward between these cells. On the 

 other hand, if the cells are in a medium or minimum granular 

 stage the capillaries are wide and open and outlined by the cement 

 substance. 



In none of my preparations have I observed true intracellular 

 secretion capillaries, notwithstanding they have been described 

 by others. It might be well to add here that the literature on 

 this particular subject is very confusing. Under the caption 

 of intracellular canaliculi, one finds at least three separate and 

 distinct types of these canals described without any particular 

 discrimination as to their nature — (a) intracellular secretion 

 canaliculi as described by E. Miiller and R. Krause; (b) intra- 

 cellular blood capillaries, in liver cells, as shown by Schafer; 

 and (c) the canalicular apparatus (reticular apparatus) (Holm- 

 gren's canals) which is found in most animal and vegetable 

 cells. The adoption of a uniform nomenclature is certainly 

 desirable in this instance. It is interesting to observe that 

 similar methods (silver impregnation) have been used for the 

 demonstration of all of these and is it not possible that in many 

 instances intracellular secretion capillaries have been described 

 when the canalicular apparatus of Holmgren alone was present .-^ 

 The latter is discussed under X. 



The cement substance of glands was first described by Heiden- 

 hain and later by Zimmermann, Bonnet, Cohn, Solger, Carlier, 

 Meyer, Oppel, Bensley, and others. Kolossow, on the other 

 hand, doubted its existence. 



I have already described the cement structures in the larger 

 ducts fVI. The Duct System and Tubules.) Cement lines are 



