SENSE OF SMELL. 411 



of air must be slow and feeble. Still more peculiar, however, 

 is it that this current of air must be inhaled, and must pro- 

 ceed from in front to back, no doubt because it is then bro- 

 ken against the spur which forms the anterior part of the 

 inferior turbinated bone, and thus portions of it rise easily 

 to the olfactory membrane. The air exhaled through the 

 posterior cavity of the nasal chambers produces no impression 

 in passing through, whatever may be the quantity of odorous 

 particles that it may contain ; the same is true if, by any 

 artificial means (injection or insufflation), a current of air is 

 directed upon the olfactory mucous, either through the open- 

 ing of the nostrils, or through a passage made in the frontal 

 and the frontal sinuses. These facts are well known to epi- 

 cures, who, when they desire to try the flavor of a wine, do 

 not breathe into the nasal chambers through the posterior 

 orifices, but breathe gently forwards and upwards through 

 the orifice of the mouth, and draw in, very slowly and by 

 short jerks, the air which comes in contact with their nos- 

 trils. 



We have seen that the seat of smell corresponds exactly 

 with the distribution of the olfactory nerve, which justifies 

 us in considering this nerve as governing this special sensa- 

 tion. Magendie supposed the sense of smell to reside in the 

 trifacial ; his reason for this was that, having cut the nerve 

 of the first pair (the olfactory) in a dog, and then held some 

 ammonia to its nose, the animal drew back and shook its 

 head ; this, however, as in the case of the tongue, was a phe- 

 nomenon of general, not of special, sensibility : the caustic 

 vapors of the ammonia acted, not on the sense of smell, but 

 on the sensibility of the Schneiderian membrane in general, 

 which is innervated by the trifacial nerve. 



Some clinical observations have, however, thrown some 

 doubts upon the functions of the olfactory nerve, considered 

 as an organ of smell : the most curious of these cases is that 

 of the autopsy of a woman, in whom Cl. Bernard found the 

 bulb and the olfactory trunk entirely wanting, and the corre- 

 sponding part of the ethmoid bone imperforate ; the strict 

 inquiry, however, established the fact that this person's sense 

 of smell had been perfect during life, and that no peculiarity 

 in this respect had ever been observed in regard to her. 

 Instances of this kind cannot be explained, but some ex- 

 periments seem to confirm the opinion that the olfactory 

 nerve has an office of special sensibility. Schiff took five 



