40 INTRODUCTION. 



Taste and smell may be considered merely as 

 finer kinds of feeling, for which the surface of the 

 tongue and of the nostrils is peculiarly organized ; 

 the former by means of papillse somewhat inflated 

 and spongy, the latter by its extreme delicacy, and 

 the perpetual renewal on its surface of mucous 

 secretion. We have already spoken of the eye and 

 of the ear in general. The organ of generation 

 appears endowed with a sort of sixth sense, resid- 

 ing in the interior skin. 



The stomach also and the intestines manifest, by 

 sensations peculiar to themselves, the state of these 

 viscera. Accident or disease may produce in 

 every part of the body sensations of greater or less 

 acuteness. 



Many animals are deficient in ears and nostrils, 

 others are destitute of eyes, and "some appear re- 

 duced to the sense of feeling only, but this last is 

 never wanting. 



The impressions made upon the external organs 

 of sense are conveyed by the nerves to the central 

 masses of the nervous system, which consist, in 

 the higher animals, of the brain and spinal marrow. 

 The more elevated any animal is in the scale of 

 creation, the greater volume of brain does it pos- 

 sess, and the more is the sensitive capacity con- 

 centrated as to a focus, there ; this sensorium is, in 

 them, seated in the head, as are also the principal 

 organs of sense ; in the more subordinate races of 

 animated beings successively, the medullary masses 

 are more and more equally dispersed ; and in the 



