of the Royal Academy of Paris, for 1824. 307 
tion a rupture of one of the crura cerebri was discovered. 
M. Majendie has not confined his observations to the centre 
of the nervous system, he has made some very curious obser- 
vations respecting the nerves distributed to the organs of 
sense. Hitherto the first pair of nerves or olfactory has been 
considered as dedicated to the organ of smell. M. Majendie, 
wishing to make an experiment which appeared to him a 
work of supererogation, to prove the correctness of an opinion 
doubted by none, cut the olfactory nerves of a young dog. 
What was his surprise the following day to find the animal 
sensible to strong odours! The experiment repeated on other 
animals afforded similar results. ‘The author suspected that 
this sensibility was to be attributed to the branches of the fifth 
pair distributed to the nostril; he accomplished the division 
of these nerves on either side, notwithstanding their depth, 
in dogs, cats, and Guinea pigs, and thus destroyed all sensibi- 
lity in the nostril. Animals which sneezed, rubbed the nose, 
and turned away the head when compelled to inhale the va- 
pour of ammonia or acetic acid, remained passive when the 
fifth pair was divided, or at least manifested only the effects 
resulting from stimulation of the larynx. This effect of strong 
-odours remained even in hens, from whose heads the whole 
cerebral hemispheres and olfactory nerves had been removed. 
We might certainly suspect that the volatile alkali acted only 
chemically on the pituitary membrane, and attribute the effects 
more to pain than smell ; in that case the pain alone would de- 
pend upon the fifth pair: but M. Majendie, who saw the force 
of this objection, observes, that it is much weaker with re- 
ference to the animal oil of Dippel or essential oil of almonds, 
which affected the organ before the fifth pair was divided, and 
lost all effect when it was cut, although the first pair remained 
untouched. What would still better rebut the objection, would 
be to prove that animals which have had the olfactory nerve 
divided, still continued to seek and distinguish their food by 
the nose. ‘The experiments on this head do not appear as yet 
conclusive, but he promises to prosecute the investigation. 
The dissections of Dr. Ramond, reported by M. Majendie, 
prove also that when the hemispheres are gorged with blood, 
or that deep and rooted alterations take place in their cortical 
substance, the sensibility of the nostril to the most delicate 
odours is not impaired. But it is not to the sense of smell 
alone that the participation of the fifth pair is essential ; it con- 
tributes to all the senses of those organs to which it is distri- 
buted ; when divided, the sense of touch is also destroyed, but 
on the anterior part of the io only; behind the ear and 4 
: ; 2 2 ; the 
