MINUTE ANATOMY OF NASAL MUCOUS MEMBRANE, 103 
the membrane at the lower sulcus, but extend at this latter 
place also a short distance into the median wall. 
There is a remarkable difference in the distribution of the 
glands between the organ in the guinea-pig and the rabbit, in 
this latter the glands being chiefly accumulated in the upper and 
outer position, just as it is described by Gratiolet and Balogh. 
The alveoli are branched and more or less convoluted tubes 
of exactly the same nature as other serous glands, e.g. the parotid. 
The transverse diameter of the alveoli varies between 0°024 and 
0-036 mm. The alveoli are limited by a membrana propria ; 
they possess a very minute lumen and are lined with a single 
layer of polyhedral or short columnar epithelial cells, each 
~~ with a spherical nucleus, situated in the outer part of the cell. 
The cell substance is a dense reticulum, and therefore appears as 
a uniformly granular protoplasm. The outline of the alveoli is 
not smooth, but shows numerous minute, rounded prominences, 
owing to some of the epithelial cells possessing a convex outer 
surface. And it is just in these cells that the projecting convex 
outer part of the cells, containing at the same time the small round 
nucleus, appears more uniform and better stained than the inner 
part, and hence the appearance is producéd very similar to 
that presented by the cells of the alveoli of the pancreas. 
The ducts are short and they take up directly the alveoli; 
they are lined with a single layer of columnar epithelial cells; in 
some instances the outer portion of the cell substanee- appears 
longitudinally striated, just like those in the salivary ducts of 
Pfliiger. The ducts open with a narrow mouth into the lower 
sulcus, where the columnar ciliated cells of the lateral wall pass 
into the mouth of the former. And these mouths form indeed 
the boundary between the epithelium of the lateral and that of 
the median wall. I have seen specimens (see fig. 5) where a 
duct opening in the lower sulcus with a narrow mouth—about 
0:012 mm. in diameter—became much distended behind this, 
and extended in this state into the wall of the organ at the 
lower sulcus to a depth of about 0°22 mm., the diameter of its 
lumen being here 0:1; and throughout this whole length it was 
lined with columnar ciliated epithelium, the length of the epi- 
thelial cells being 0°02 mm., the length of their cilia about 
0006 mm. In this same specimen from which fig. 5 is taken 
Jacobson’s cartilage was wanting almost everywhere except at 
the upper sulcus. 
2. The median wall. As such will be considered that part of 
the circumference of the organ which is not strictly limited to 
the median line of the nasal septum, but which is covered with 
a thick epithelium; this, owing to its peculiar nature, is the 
‘ sensory epithelium,” 
