178 



ON THE EXTERNAL SENSES 



it resides partly in the tongue, and tips of the fingers, as in man, buf 

 equally, and in some species even in a superior degree, in their toes. In 

 the racoon (ursus lotor) it fexists chiefly in the under surface of the front 

 toes. In the horse and cattle orders, it is supposed by most naturalists to 

 exist conjointly in the tongue and snout, and in the pig and mole to be con- 

 fined to the snout alone : this however is uncertain ; as it is also, though 

 there seems to be more reason for such a behef, that in the elephant it is 

 seated in the proboscis. Some physiologists have supposed the bristly 

 hairs of the tiger, lion, and cat, to be an organ of the same kind ; but 

 there seems little ground for such an opinion. In the opossum (and es- 

 pecially the Cayenne opossum) it exists very visibly in the tail ; and M. 

 Cuvier suspects that it has a similar existence in all the prehensile-tailed 

 mammals. 



Blumenbach supposes the same sense to have a place in the same organ 

 in the platypus or ornithorhynchus as he calls it, that most extraordinary 

 duck-billed quadruped which has lately been discovered in Australia, and, 

 by its intermixture of organs, confounds the different classes of animals, 

 and sets all natural arrangement at defiance. 



The local organ of touch or feehng in ducks and geese, and some other 

 genera of birds, appears to be situated in the integument which covers 

 the extremity of the mandibles, and especially the upper mandible, with 

 which apparatus they are well known to feel for their food in the midst df 

 mud in which they can neither see nor perhaps smell it. 



We do not know that amphibials, fishes, or worms possess any thing 

 like a local sense of touch ; it has been suspected in some of these, and 

 especially in the arms of the cuttle-fish, and in the tentacles of worms that 

 possess this organ, but at present it is suspicion and nothing more. 



In the insect tribes, we have much reason for believing such a sense to 

 reside in the antennas, or in the tentacles ; whence the former of these 

 are denominated by the German naturalists /wAZ/iomer or feeling-horns» 

 This belief has not been fully estabhshed, but it is highly plausible, from 

 the general possession of the . one or the other of these organs by the 

 insect tribes, the general purpose to which they apply them, and the ne- 

 cessity which there seems for some such organ from the crustaceous or 

 horny texture of their external coat. 



The senses of taste and smell in animals bear a very near affinity 

 to the local sense of touch ; and it is diflicult to determine whether the 

 upper mandible of the duck tribe, with which they distinguish food in the 

 mud, may not be an organ of taste or smell as well as of touch ; and 

 there are some naturalists that in hke manner regard the cirrous filaments 

 or antennules attached to the mouths of insects as organs of taste and 

 touch equally. Taste in the more perfect animals resides jointly in the 

 papillae of the tongue and the palate ; but I have already had occasion to 

 observe that it may exist, and in full perfection, in the palate alone, since 

 it has been found so in persons who have completely lost the tongue from 

 external force or disease. 



In animals that possess the organ of nostrils this is always the seat of 

 smell ; and in many quadrupeds, most birds, and perhaps most fishes, it 

 is a sense far more acute than in man, and that which is chiefly confided 

 in. For the most part it resides in the nerves distributed over a mucous 

 membrane that lines the interior of the bones of the nostrils, and which 

 13 called the Schneiderian membrane, in honour of M. Schneider, a cele- 

 brated anatomist, who first accurately described it. Generally speaking, 



