THE ORGAN OF JACOBSON IN THE RABBIT, 559 
send their ducts through the epithelium of the lateral wall verti- 
cally and straight through the middle of the lateral wall. These 
glands do not extend through the whole subepthelial layer from 
the upper to the lower sulcus, but are limited chiefly, as stated 
above, to the middle part of the lateral wall, hence the fold; 
above and below the gland the subepithelial layer contains 
numerous lymph-corpuscles as before. 
This glandfold remains now through the whole length of the 
organ of Jacobson to near its posterior extremity. 
The presence of this glandfold in the lateral wall necessitates 
a change in the shape of the cavity of the organ of Jacobson; 
whereas the cavity in transverse section through the anterior 
regions appears more or less oval, it now for obvious reasons 
possesses the shape of a bean or kidney (compare figs. 10 and 11). 
The cartilage of Jacobson, being trough-shaped with an upper 
opening, it follows that the glands in the upper part of the wall 
of the organ of Jacobson, viz. those, the ducts of which open in 
the upper sulcus, form an unbroken continuity through that 
opening with the serous glands of the mucous membrane covering 
the septal cartilage. These points, ¢.¢. the presence of a gland- 
fold in the lateral wall, the continuity of the glands of the 
organ of Jacobson with those of the mucosa covering the septal 
cartilage, together with the above-mentioned trough-shaped 
nature of Jacobson’s cartilage, form the chief differential 
characters by which to distinguish at once the sections placed 
through the most anterior portions of the organ of Jacobson 
from those made of the rest, except the posterior extremity, which 
will be considered presently. 
In some places the median wall of the organ of Jacobson contains a 
few alveoli of serous glands ; these are evidently outrunners from the glands 
of the lower wall, that is, those opening into the lower sulcus. 
In these respects, then, the organ of Jacobson differs consi- 
derably from that of the guinea-pig, as described in my former 
papers, while it approaches to a certain limited extent that of 
the typical organ of the mammal, as described by Gratiolet, and 
that of the sheep, as described by Balogh. Gratiolet! speaks of 
the upper wall as possessed of a “ bourrelet saillant,” and con- 
taining numerous glands, but it is quite clear from his descrip- 
tion that this ‘‘bourrelet saillant” is not the same thing as our 
“‘ slandfold,” since, besides its different position, he ascribes 
it not to a separate group of glands, but to the glands in general. 
He also speaks? “d’un grand sinus veineux qui régne dans toute 
l’étendue du bourrelet.”’ 
RAEG,; Pe 205 
7L.¢., p. 21. 
