SMELL. 



283 



called the Schneiderian membrane,* which is constantly 

 kept moist, is supplied with numerous blood vessels, and 

 upon which are spread the ultimate ramifications of the ol- 

 factory nerves. The relative magnitude of these nerves is 

 much greater in carnivorous quadrupeds than in those which 

 subsist on vegetable food. In quadrupeds as well as in man, 

 these nerves are not collected into a single trunk in their 

 course towards the brain, but compose a great number of fila- 

 ments, which pass separately through minute perforations 

 in a plate of bone, (called the ethmoid bone) before they en- 



382 



N 



ter into the cavity of the skull, and join that part of the ce- 

 rebral substance with which they are ultimately connected. 

 The surface of the membrane which receives the impres- 

 sions from odorous effluvia, is considerably increased by 

 several thin plates of bone, which project into the cavity of 

 the nostrils, and are called the turbinated bones. These are 

 delineated at T, T, in Fig. 3S2, as they appear in a vertical 

 and longitudinal section of the cavity of the human nostril, 

 where they are seen covered by the Schneiderian mem- 



* It has been so named in honour of Schneider, the first anatomist who 

 gave an accurate description of this membrane. 



