The Structure of the Mammalian Csophagus. 29 
mass of tissue the apex of which is directed towards the duct, the 
base towards the periphery of the lobule. These pyramidal masses 
are the units of structure, being composed exclusively of tubules and 
acini lined by secreting cells. As indicated above, the gland is 
tubulo-acinous in type, the body of the unit composed of branching 
tubules which terminate in bulb-like acini, tubules and acini being 
occupied by the same type of epithelial cell. The acini show a 
slight expansion of the lumen and the cells are frequently longer in 
the acini than in the tubules, thus accounting for the difference 
in size. 
To the question of the presence of demilunes in the esophageal 
elands of man I have given much attention. In view of the fact 
that I have found these structures without difficulty in all cesophageal 
elands of other mammals it was my expectation that they would 
also be found in man. Accordingly I have studied carefully com- 
plete series of sections, 5 micra thick, of glands from three different 
wsophagi, using the methods of staining which I have found most 
efficient in demonstrating these structures in other mammals. The 
result of this study has, however, been wholly negative and I am 
foreed to agree with Schaffer, who states that the human cesophageal 
elands are pure mucous glands without demilunes. Referring to 
the literature I find that neither Klein (79) nor Renaut (97), who 
are quoted in this connection by Schaffer and Oppel, specifically 
state that they found demilunes in the human cesophagus, although 
the former found them in the dog and Renaut’s description applies in 
general to the dog and man. Bohm and v. Davidoff (95) state that 
there are but few mucous glands in the esophagus but that when 
present they contain well marked demilunes, but it is diffieult to 
determine whether these authors had before them the true cesophageal 
elands occurring in the submucosa, or the superficial glands of 
Riidinger which have been shown by Schaffer (97) and Hewlett 
(00) to contain parietal cells and from which their illustration of 
the cesophageal glands of man is clearly taken. 
The character of the mucous cells forming the secreting tubules 
is well shown in Fig. 12. Protoplasmic cells containing no mucin as 
described by Schaffer occur also in my preparations, whole groups 
