100 DR. E. KLEIN. 
membrane covering the cartilaginous nasal septum, but this 
does not hold good in the guinea-pig. 
Gratiolet speaks! of the tissue in that slit as of “ une sorte de 
mesentere.” In the guinea-pig, however, the above-mentioned 
plough-shaped projection of the upper part of the cartilage of 
Jacobson includes one or two spacious longitudinal channels or 
clefts for the branches of the nerves and blood-vessels supplying 
the organ of Jacobson. 
Figs. 1 and 2 of Plate VII give an accurate representation 
of the relation of the cartilage of Jacobson to the organ of 
Jacobson, and to the cartilaginous nasal septum. Both figures 
were made with the camera, and their respective preparations were 
obtained from the same organ of Jacobson at different places. 
In fig. 1 the capsule is complete; in fig. 2 it is incomplete in 
some places ; while in others the cartilage is reduced in thickness 
to a very considerable degree. 
Balogh,” in his description and illustrations of the cartilage of 
Jacobson in the sheep, introduces a perfectly unnecessary and 
complicated terminology of the different parts of the cartilage. 
As far as I can understand his elaborate description (pp. 451 
and 452), the cartilage does not differ much from that described 
by Gratiolet of other mammals. Balogh does not know of 
Gratiolet’s work, otherwise he might have been able to follow 
this latter’s simple description. 
As mentioned above, the organ of Jacobson is flattened, and, 
therefore, its walls are generally considered as the lateral and 
median wall, the latter being the one nearest to the median line 
of the septum. For a better understanding we shall speak, in 
addition, of an upper and lower sulcus, meaning the parts where 
the lateral and median walls are in contact. 
In the guinea-pig the outline of the transverse section is not 
simply oval, but is kidney-shaped, the lateral wall being pressed 
inwards, z.e. against the Jumen or cavity of the organ. 
The size of the organ is about the same on both sides. 
Gratiolet mentions, in the upper and outer part of the organ, a con- 
spicuous projection, “un bourrelet saillant, que je ne saurais mieux com- 
parer qu’al’organe décrit dans l’intestin du lombric sous le nom d’intestinum 
in intestino.” 
Balogh‘ finds in the organs of the sheep a similar projection of the wall 
from the upper outer part, ‘ Drusenwulst.” But in the guinea-pig there is 
no such projection from the upper part of the wail, the lateral wall as a 
1 Loe. cit., p. 19. 
2 « Sitzungsber. d. Kais. Akadem. d. Wiss.,’ Vienna, volume 42, p. 449, 
“ Das Jacobson’sche Organ des Schafes.” 
3 Loc. cit., p. 20. 
$ Loc. cit., p. 457. 
