SOi DR. E. KLEIN. 



median wall is the one nearest to the middle line of the 

 nose. 



(a) The cartilage of Jacobson. As has been described 

 above, at the most anterior section of the organ the cartilage 

 of Jacobson is directly continuous witli that of Stenson's 

 canal (figs. 4 and 5). At first, and before entering the nasal 

 septum, the cartilage of Jacobson is a curved plate, cres- 

 centic in transverse section (figs. 5, 6, and 7), and increasing 

 in thickness and extent from forward to backward. Having 

 entered the nasal septum the cartilage of Jacobson, while 

 considerably larger than in front, has become crook-shaped, 

 as is shown in fig. 8. We may now distinguish on it a 

 larger or vertical labium and a smaller or horizontal 

 labium. The former is much thicker at its upper extremity 

 than in any other part. Passing backwards, we find in the 

 whole length of the organ the cartilage of the same shape 

 and position as is seen in figs. 9, 10, and 11, but the size 

 varies, for the vertical labium becomes very much longer 

 than in front (see figs. 10 and 11). In the middle part of 

 the organ the horizontal labium of the cartilage possesses a 

 minute lateral projection (fig. 10), which causes here a similar 

 bulging out of the mucous membrane of the surface of the 

 nasal septum — ^Jacobsou's projection. Near the posterior 

 extremity Jacobson^s cartilage changes slightly in shajje, 

 as the extremity of the horizontal labium becomes sligbtiy 

 curved upwards (see fig. 12). At the very end of the organ 

 the horizontal labium altogether disappears, and also the 

 vertical labium becomes slightly shortened (fig. 13). This 

 horizontal labium extends for a short distance beyond the 

 extremity of the organ of Jacobson as a smooth plate of 

 cartilage, and ultimately terminates with a blunt extremity. 



As regards the structure of Jacobson's cartilage there is 

 very little to be said ; it is hyaline cartilage, many of the 

 cartilage cells containing either one large or many small 

 oil globules. In the latter instance the cells show a 

 beautiful honeycombed network as a framework for the oil 

 globules. 



Before the organ of Jacobson enters the nasal septum, 

 i. e. before it passes through the bone, and while still con- 

 tained in the membrane of the palate, the epithelium lining 

 the lumen is stratified pavement epithelium of very nearly 

 the same nature and thickness as that lining Stenson's canal. 

 Underneath the epithelium is a dense fibrous membrane, 

 containing in the lateral wall, i, e. the wall next the canal 

 of Steiison (see figs. 6 and 7), very numerous lymphoid 

 corpuscles. Outside the subepithelial dense membrane is a 



