302 DR. E. KLEIN. 



epithelium remains of this character throughout the canal. 

 (b) Underneath the epithelium is the mucous membrane, 

 which, like that of the palate, is dense fibrous tissue with the 

 usual capillary networks. Numerous elastic fibrils running 

 in a longitudinal direction are met with between the 

 bundles of connective tissue. There are indications only of 

 papillae. The tissue belonging to the wall of the canal is 

 not well defined from the surrounding fibrous tissue, except 

 that it is loose in its texture, (c) The cartilage is hyaline 

 and does not present any peculiarity of structure. The 

 shape of it and its relation to Jacobson's cartilage have been 

 mentioned above. 



The following measurements give an idea of the size of 

 these different parts : 



At a point illustrated in fig. 6 the long transverse dia- 

 meter is about 1*17 mm. Tlie short transverse diameter 

 through the broadest point about 0*675 mm. The thick- 

 ness of the epithelium is about 0'3375 mm. 



2. The organ of Jacobson. As has been pointed out 

 above, the organ or tube of Jacobson opens into Stenson's 

 canal below the bone of the palate ; from this opening to the 

 point where the organ of Jacobson has entered the nasal 

 septum, i.e. beyond the point where the Stenson's canal has 

 opened into the nasal furrow, and consequently has ceased 

 to exist as such, the organ of Jacobson is comparatively a 

 small tube with a lumen circular in transverse section. 



Figs. 6, 7, and 8 show these points distinctly. In figs. 6 

 and 7 the organ of Jacobson is still in company with Sten- 

 son's canal and below the osseous palate; in fig. 8 Stenson's 

 canal is no more, and the organ of Jacobson is already con- 

 tained in the nasal septum. 



Throughout the rest of the organ except the most hind 

 portion, the lumen of the organ is more or less kidney- 

 shaped, owing to the lateral wall possessing a convex, the 

 median wall a concave, surface. In about the middle of the 

 organ and a little anterior to it, this condition is best deve- 

 loped. In figs. 9, 10, and 11 the relative size and shape of 

 the organ are well shown. At the posterior extremity of 

 the organ the transverse diameter decreases considerably, 

 and the shape of the organ alters in this manner, that although 

 its lumen in transverse section is still convex-concave, the 

 upper sulcus of it extends upwards in the shape of a long 

 thin cleft. At the very end of the organ the lumen becomes 

 smaller, elliptical in transverse section, and ultimately is 

 altogether lost. In figs. 12 and lo these relations are easily 

 recognised. 



