OF NATURAL HISTORY. S33 



* a man,' fays the Count de Buffon, ' were deprived of fight, he 

 ' would make no movement to gratify his eyes. The fame thing 



* would happen, if he were deprived of any of the other fenfes ; 

 ' and, if deprived of every fenfe, he would remain perpetually at 

 ' Veft, and no objedt would excite him to move, though, by natural 

 ' conformation, he were fully capable of motion.' Natural wants, 

 as that of taking nourillament, neceffarily excite defire or appetite. 

 But, if a man be deprived of fenfation, want cannot exift, becaufe 

 all its fources are annihilated. This is cutting off all the caufes, and 

 at the fame time looking for the efFeds. An animal without feme 

 fenfation is no animal, but a dead mafs of matter. Sentiment is the 

 only ftimulus to animal motion ; the aptnefs of the parts produces 

 the effed, which varies according to the ftrudture and deftination of 

 thefe parts. The fenfe of want creates defire. Whenever an ani- 

 mal perceives an objedt fitted to fupply its wants, defire is the ne- 

 ceflary confequence, and adion or motion inftantly fucceeds. 



Befide progreflive motion, the motion of hands, and other parts 

 of animal bodies, which are all efFedted by means of mufcles, and 

 are fubjed to the will of the creatures who perform them, there are 

 other motions that have little or no dependence on our inclinations. 

 Of this kind are the adion of the heart, the circulation of the blood-, 

 the digeftion of food, the periftaltic motion of the bowels^ the pro- 

 grefs of the chyle from the ftomach and inteflines to the fubclavian 

 vein, the movement of the various fecreted liquors, fuch as the gall, 

 the urine, the faliva, &c. Thefe, together with the adion of the 

 kmgs in refpiration, have received the denomination of vital and in- 

 "voluntary ffw//o7ZJ, becaufe moft of them go on without any confcious 

 exertions of the intelledual principle. If fuch a variety of nice and 

 complicated movements had been left to the determination and di- 

 redion of our minds, they muft neceffarily have occupied too much 

 of our attention ; and many of them would infallibly have been ne- 



gleded. 



