oo INTRODUCTION. 



calling them sponge-like laminae, irregularly convoluted. Over the 

 walls of these cavities, and over these turbinated and spongy plates, a 

 fine mucous membrane is spread, on which the minute and multitudi- 

 nous fibres of the olfactory nerves ramify. In most animals the olfac- 

 tory apparatus is far more extensively developed than in Man ; on the 

 sense of smell depends their selection or discovery of food : thus it 

 ministers to their necessities, but to their necessities alone. Though 

 among the savage tribes of the human race, the sense of smell, from 

 habitual exercise, as a consequence of an almost brute-like mode of life, 

 may be more acute than in civilized races, yet in Man it is less dis- 

 criminative than in most other Mammalia. Nature does not bestow 

 her gifts without designing to confer advantage ; and, where none is to 

 be gained, the endowment, which, if possessed, might be even injurious, 

 is denied. Man does not depend, for his daily maintenance, on the per- 

 fection of this sense, which, to so many of the lower race, is of main 

 importance. He can, indeed, distinguish and relish the grateful odour 

 of flowers, the summer scents that fill the air with fragrance, and the 

 perfume of gums and spices : he is affected with disgust by the noisome 

 effluvia of other objects, but he cannot, like the hound, track the foot- 

 steps of the distant quarry ; nor, like the Buffalo or Rhinoceros, perceive, 

 by his power of smell, the approach of the Lion, or other enemies. The 

 sense of smell ministers less to the animal necessities in Man than in the 

 brute, but more to the intellectual faculties : modified, as he possesses 

 it, it becomes an agent in the acquisition of knowledge, and is a source 

 of pleasure or disgust, unconnected with the mere supplies of life. 



It is here to be observed, that, besides the true nasal cavities* 

 which have already been pointed out, there are connected with them 

 other cells, or cavities, lined by a continuation of the same membrane, 

 but of a thinner texture, and supplied by a finer mesh of blood-vessels. 

 Two of these cavities are in the frontal bone (or one in each frontal 

 bone where that bone is double), above the orbits ; they are termed the 

 frontal sinuses. One occurs in each superior maxillary bone, below the 

 eye, and is termed the antrum Highmorianum (cavern of Highmore) ; 

 and two of inconsiderable size exist in the body of the sphenoid. In Man 

 the frontal sinuses are of small extent, and are usually defined by a slight 

 projection of the bone, to be perceived above the inner angle of each eye, 

 on the edge of the forehead. 



In the Ape tribe, notwithstanding the strong superciliary ridge, which 

 gives such a peculiar and sinister expression to the countenance, these 

 sinuses are obliterated.* In many Mammalia, however, they are of 

 large extent, and occupy the whole of the forehead and crown, giving an 

 appearance of greater development to the anterior part of the brain than 



* At least the Author has been able to detect no trace of them, even by making a section of the bone. 



