THE LACHliYMAL GLAND 227 



In the primary ducts a gratliial reduction of both goblet cells 

 and the layers of epithelial cells takes place. The interlobular 

 ducts possess no goblet cells, and two layers of epithelial cells 

 form the lumina. In the intralobular ducts one or two layers 

 of epithelial cells are seen. The outer layer gradually disappears 

 in the smaller intralobular ducts and in the intercalary ducts. 



5. Secretion granules are present in both the intercalary duct 

 and in the tubules. They are not found in the other ducts. 

 The granules are readily seen in all fresh glands when examined 

 in serum or isotonic salt solution. They disappear when the 

 fresh cells are placed in distilled water but reappear upon the 

 addition of 2 per cent sodium chloride solution. 



6. The granules in the intercalary ducts are preserved when 

 the tissue is fixed in Zenker's solution and stain specifically in 

 muchaematein and mucicarmin. They are not stained — when 

 fixed in Zenker's — with the serous granule stains. The granules 

 in the tubules are not preserved as a rule in Zenker's solution. 

 This phenomenon suggests that the cells or the tubules may 

 differ in function from those of the intercalary duct. I am not 

 prepared, however, to make this claim. 



7. The granules of both the intercalary duct and the tubules 

 are fixed in Bensley's alcohol sublimate bichromate solution and 

 in formalin bichromate sublimate solution. When tissues are 

 fixed in these solutions the granules in both the tubules and 

 intercalary ducts stain in the well known mucous stain — muc- 

 haematein and mucicarmin as well as in the serious granule stains 

 iron haematoxylin, copper chrome haematoxylin, neutral gen- 

 tian, neutral safranin. After staining tissues fixed in the former 

 solution with iron haematoxylin and then counterstaining with 

 mucicarmin, all the granules in certain cells stain black with the 

 former stain and all the granules in other cells stain red in the 

 latter, while in other cells both black and red granules are seen — 

 thus showing that even within the same cell some of the secretion 

 granules are affected by serous stains while others are affected 

 by mucous stains. Notwithstanding this double staining re- 

 action, there is not sufficient evidence to claim that the cells 

 forming the tubules are heterogeneous in character. 



