30 SPECIAL SENSES. 



be evident to any one who reads the experiments of Magen- 

 die, in which he attempted to show that the sense of smell 

 was retained after division of these nerves, that he confused 

 the general sensibility of the parts with the peculiar impres- 

 sions of odors ; and the cases, especially the one reported by 

 Bernard, in the human subject, in which it was supposed 

 that the olfactory sense existed, notwithstanding congenital 

 absence of the olfactory nerves and bulbs, 1 are by no means 

 satisfactory, in view of the numerous instances in which pre- 

 cisely the opposite has been observed. 



The more recent experiments upon animals are entirely 

 conclusive as regards the effects of division of the olfactory 

 nerves. Eschricht published, in 1826, a curious experiment 

 in contradiction to one of the observations of Magendie. He 

 extirpated, in a toad, the cerebral hemispheres and the olfac- 

 tory bulb and nerves. Upon applying liquor ammonise to 

 the nostrils of the animal, it drew back, moved the head and 

 rubbed its nose with the fore-feet ; movements which had led 

 Magendie, in similar experiments, to conclude that the sense 

 of smell was not destroyed. Eschricht, in repeating this ex- 

 periment, applied the ammonia to the anus. The animal 

 then moved forward, contracted the sphincter repeatedly, and 

 rubbed the anus with its feet (" prorsum animal procurrebat, 

 celerrimus erat sphincteris motus et quomodo anterior pes 

 antea nasum, ita posterior anum palpabat "). a If the first ex- 

 periment of Magendie showed that the sense of smell was 

 retained, the experiment of Eschricht would equally show 

 that the mucous membrane of the anus of the animal operated 

 upon was endowed with olfactory sensibility. 



Among the numerous experiments upon the higher orders 

 of animals, in which the olfactory nerves have been divided, 

 we may cite, as open to no objections, those of Yulpian and 

 Philipaux, on dogs. It is well known that the sense of smell 



1 BERNARD, Systime nerveux, Paris, 1858, tome ii., p. 229. 



2 ESCHRICHT, De Functionibus primi et quinti Paris Nervorum in olfactoris 

 Organo propriis. Journal de physiologic, Paris, 1826, tome vi., p. 350, note. 



