OF THE SENSE OF TASTE. Ill 



211. By touch we appreciate most of the physical pro- 

 perties of bodies, such as their dimensions, form, temperature, 

 consistence, polish or the opposite, weight, movements, <fcc. 

 Some philosophers have adopted exaggerated ideas of the 

 importance of this sense to human intelligence, for which 

 there is not the slightest occasion. 



OF THE SENSE OF TASTE. 



212. By this sense we discover the savours of 

 bodies. 



213. Certain bodies are extremely sapid, others but 

 little, and some not at all. The cause of these differences is 

 quite unknown ; but, generally speaking, insoluble bodies are 

 not sapid, and when the tongue is dry and parched the taste 

 is not perceived. 



214. By taste most animals distinguish their food ; and 

 hence, no doubt, the reason why the instrument is placed at 

 the entrance of the digestive tube. The tongue is the prin- 

 cipal seat of taste ; but other parts of the mouth possess the 

 power of perceiving certain savours. The mucous membrane 

 which covers the tongue of man is sufficiently well supplied 

 with bloodvessels and nerves supplying papillae of various 

 forms lenticular, fungiform, and conical. The tongue itself 

 is muscular, and receives branches of motor and sentient 

 nerves. A branch of the fifth pair is the gustatory ; it is 

 sometimes called lingual. 



215. If this nerve be cut in the living animal, the sense 

 of taste is destroyed, but the movements of the tongue 

 remain ; if divided within the cranium, the sense of taste is 

 destroyed all over the interior of the mouth. 



The section of the hypoglossal nerves destroys the motion 

 of the tongue and of all other parts to which these nerves 

 proceed. The sense of taste remains unaffected. The 

 glossopharyngeal, distributed chiefly to the pharynx, and 

 which are sensitive nerves, have also some gustatory 

 powers. 



216. The tongue has nearly the same structure in all 

 animals ; but in birds it is generally cartilaginous, and without 

 nervous papillae; accordingly, their sense of taste is con- 

 sidered as obscure. It is much the same in fishes ; and in 

 the lower animals, the faculty seems to be exercised by all 

 the interior of the mouth. 



