PARTS OF ANIMALS, II. xvi. 



gether, and similarly all the bottom teeth, and then 

 each set were extended in a forward direction, and 

 made to taper : this Avould result in a beak such as 

 birds have.) In all animals except man the lips are 

 intended to preserve and to protect the teeth ; hence 

 Λve find that the distinctness of formation in the lips 

 is directly proportionate to the nicety and exactitude 

 of formation in the teeth. In man the lips are soft 

 and fleshy and can be separated. Their purpose is 

 (as in other animals) to protect the teeth ; but — 

 still more important — ^they subserve a good pur- 

 pose, inasmuch as they are among the parts that 

 make speech possible. This double function of the 

 human lips, to facilitate speech as Avell as to protect 

 the teeth, may be compared with that of the human 

 tongue, which is unlike that of any other animal, and 

 is used by Nature for two functions (a device of hers 

 which we have often noted), (a) to perceive the 

 various tastes, and (h) to be the means of speech. 

 Now vocal speech consists of combinations of the 

 various letters or sounds, some of which are produced 

 by an impact of the tongue, others by closing the lips ; 

 and if the lips Avere not supple, or if the tongue were 

 other than it is, the greater part of these could not 

 possibly be pronounced. For further particulars 

 about the various diiferences between these sounds 

 you must consult the authorities on Metre. 



Itv.'as weceiiari/, however, from the start that each of 

 these two parts should be adapted and well-fitted for 

 their function as stated above ; therefore their nature 

 had to be suitable thereto, and that is why they are 

 made of flesh. Human flesh is the softest kind of flesh 

 there is ; and this is because man's sense of touch is 

 much more delicate than that of any other creature. 



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