416 BIOLOGY. 



from all parts, and particularly from the spinal cord, so 

 also is this the case with the intestinal sense, which is 

 still only an internal tegumentary sense. The lingual 

 nerves proceed from several situations, and that too from 

 the upper part of the spinal cord. 



2464. The oral cavity also consists, properly speaking, 

 of mere tactile organs, which have been repeated in the 

 head. Thus, there are tactile organs which are subservient 

 to the gustatory sense, in biting, chewing, and swallowing. 



2465. The lips are tactile organs upon the threshold 

 or brink, as it were, of the gustatory sense. 



2466. In the oral cavity, however, the glands of the 

 intestinal canal are repeated. The salivary glands secrete 

 fluid, like the pancreatic glands. 



2467. The sense of feeling is present in all animals. 

 They are only animals by virtue of it ; but the sense of 

 taste appears to be first formed at a later period, after 

 the intestine has separated from the integument ; in the 

 animals that have no intestine, its existence is proble- 

 matical, and even in Fishes and Birds it is but poorly 

 developed. 



3. Pulmonic or Lung-sense. 



2468. When the respiratory organ is hoisted up into 

 the head, and there becomes an organ of sensation, it 

 passes over into a sense. 



2469. That the nose is the thorax, together with its 

 viscera, repeated in the head, has been already remarked. 

 The many convolutions of the turbinated or olfactory 

 bones correspond to the ramifications of the trachea ; the 

 nasal cartilages to the tracheal or laryngeal rings ; the 

 olfactory membrane to the pulmonic vesicles. 



2470. The process of the lungs repeated in the head 

 becomes smell, like that of the intestine became taste. 

 The olfactory sense is the highest blossom of the arteriose 

 vascular system or the branchial net. On this account 

 the olfactory membrane is the most delicate, and the 

 densest tissue of arteries and veins. 



2471. The nose is related to the mouth, as the tho- 



