350 THE SENSORIAL FUN( TIONS. 



its niastei' by the scent alone, through the avenues 

 and turnings of a crowded city, accurately distin- 

 guishing his track amidst thousands of others. 



The utility of the sense of smell is not confined 

 to that of being a check upon the respiration of 

 noxious gases; for it is also a powerful auxiliary to 

 the sense of taste, which of itself, and without the 

 aid of smell, would be very vague in its indications 

 and limited in its range. What may have been its 

 extent and delicacy in man while he existed in a 

 savage state, we have scarcely any means of deter- 

 mining ; but in the present artificial condition of 

 the race, resulting from civilization and the habitual 

 cultivation of other sources of knowledge, there is 

 less necessity for attending to its perceptions, and 

 our sensibility to odours has probably diminished 

 in the same proportion. It is asserted both by 

 Soemmerring and Blumenbach that the organ of 

 smell is smaller in Europeans and other civilized 

 races of mankind, than in those nations of Africa 

 or America, which are but little removed from a 

 savage state : it is certainly much less developed in 

 man than in most quadrupeds. To the carnivorous 

 tribes, especially, it is highly useful in enabling them 

 to discover their natural food at great distances. 



The cavity of the nostrils, in all terrestrial verte- 

 brated animals, is divided into two by a vertical 

 partition ; and the whole of its internal surface is 

 lined by a soft membrane, called the Schneiderian 

 membrane * which is constantly kept moist, is sup- 

 plied with numerous blood-vessels, and upon which 

 are spread the ultimate ramifications of the olfac- 



* It has been so named in honour of Schneider, the first anato- 

 mist who gave an accurate description of this membrane. 



