578 
iTlterrUanfnu 
A Duct in the Palate connected nith the Senses 
of Smell and Taste. 
The wonderful acuteness and power of discrimination which 
many animals exercise in the discovery and selection of their food, 
have often suggested the existence of new senses, different from 
those which we possess, and conveying peculiar and unknown 
powers of perception. 
An organ which appears to perform some sensitive function of 
this kind has been discovered in a great number of quadrupeds 
by Jacobson # . In the human skeleton there exists a small per- 
foration in the roof of the mouth, just behind the sockets of the 
incisor teeth, forming a communication with the under and fore 
part of the nostrils. This canal is perceptible only in the dried 
bones ; for in the living body it is completely closed by the mem- 
brane lining the mouth, which sends a prolongation into it: but 
in quadrupeds this passage is pervious, even during life, and is 
sometimes of considerable width. Jacobson found, on examining 
this structure with attention, that the canal led to two glandular 
organs of an oblong shape, and inclosed in cartilaginous tubes : 
each gland has in its centre a cavity which communicates above 
with the general cavity of the nostrils. These organs lie con- 
cealed in a hollow groove beneath the bone, where they are care- 
fully protected from injury; and they receive a great number of 
nerves and bloodvessels resembling in this respect the organs of 
the senses. Their structure is the same in all quadrupeds in 
which they have been examined ; but they are largest in the fa- 
mily of the Rodentia , and next in that of the Ruminantia : in 
the horse they are very large, but the duct is not pervious; 
while in carnivorous animals they are on a smaller scale. In 
monkeys they may still be traced, although extremely small; ap- 
pearing to form a link in the chain of gradation connecting this 
tribe with the human race, in whom every vestige of these organs 
has disappeared, excepting the aperture in the bones already 
noticed. Any use that can be attributed to these singularly 
constructed organs must evidently be quite conjectural. The 
ample supply of nerves which they receive would indicate their 
performing some sensitive function; and their situation would 
point them out as fitting them for the appreciation of objects 
presented to the mouth to be used as food : hence it is probable 
that the perceptions they convey have a close affinity to those of 
smell and taste. 
Roget’s Bridgewater Treatise , vol. ii, p. 568. 
* Sec Annalcs du Musee, vol. xviii, p.412. 
