556 DR, U. KLEIN. 
T now come to the essential part of this paper, viz. the descrip- 
tion of the structure of the tissues forming the wall of the organs 
or tubes of Jacobson. 
In the guinea-pig, as has been pointed out in my paper of 
this year’s April number of this Journal, the mucous membrane 
lining the depth of the nasal furrow is in the front part of the 
nasal organ covered with stratified pavement epithelium, and the 
mucosa itself contains, like the mucosa of the neighbouring parts, 
a plexus of veins longitudinally arranged and is infiltrated with 
numerous lymph-corpuscles. The same epithelium and structure 
of the mucous membrane of the nasal furrow, except that the 
infiltration with lymph-corpuscles is here much less marked than 
in the guinea-pig, is also met with in the front part of the nasal 
organ of the rabbit, and I can therefore pass this over without 
any further details, and will refer the reader to figs. 1, 2 and 
3, of the present memoir. 
As in the guinea-pig, so also in the rabbit, there exists an 
open communication of the tubes or organs of Jacobson with 
the lower nasal furrow by means of a narrow mouth, such as is 
shown in fig. 3.1. In front of this opening we notice in the 
mucous membrane of the nasal furrow a conspicuous plexus 
of large veins, the tissue between which contains bundles 
of muscular tissue, that is to say, we have here already to deal 
with a cavernous tissue similar to that occurring in the lateral 
wall of the organ of Jacobson, at and about. the mouth, such as is 
represented in fig. 8. The cavernous tissue is a conspicuous part 
of the mucous membrane and occupies the part of this latter which 
corresponds to the lower wall of Jacobson’s cartilage. The part 
of the mucous membrane corresponding to the median labium of 
Jacobson’s cartilage is more or less occupied by glands extending 
downwards and upwards, so as to form a continuity with those 
contained in the mucous membrane of the nasal furrow and septum 
respectively. 
All these glands, be it said once for all, whether in the wall of 
Jacobson’s organ, or in the mucous membrane of the nasal septum, 
or the concha inferior, or the wallsof the nasal furrow, are always 
serous glands of exactly the same nature as those described in my 
former papers; the ducts are lined with a single layer of columnar 
cells, whose outer portion is conspicuously fibrillated, just as in the 
salivary tubes of Pfliiger. 
The mouth of Jacobson’s organ is lined with stratified pave- 
ment epithelium; the subepithelial tissue contains numerous 
lymph-corpuscles. Immediately past the mouth the epithelium 
is stratified columnar all round the lumen of the now closed tube 
1 My friend Dr. Reuben Harvey, of Dublin, informs me that he found 
the same condition also in the rat and cat, 
