242 Human Frame. 



mission, and the strainers must be always 

 employed; therefore, there is actually a 

 perpetual circulation of the blood, and 

 the secretions are always going on. Even 

 all this provision, however, would not be 

 -sufficient ; for that store of blood would 

 be soon consumed, and the fabric would 

 break down, if there were not a provision 

 made for fresh supplies. These we ob- 

 serve in fact are profusely scattered round 

 her in the animal and vegetable king- 

 doms ; and she is furnished with hands, 

 the fittest instruments that could have 

 been contrived, for gathering them, and 

 for preparing them in a variety of ways 

 for the mouth. But these supplies, which 

 we call food, must be considerably ch^ng- 

 ed ; they must be converted into blood. 

 Therefore, she is provided with teeth for 

 cutting and bruising the food, and with a 

 stomach for melting it down ; in short, 

 with all the organs subservient to diges- 

 tion. The finer parts of the aliments on- 

 ly can be useful in the constitution : these 

 must be taken up and conveyed into the 

 blood, and the dregs must be thrown off* 

 With this view, the intestinal canal is ac- 

 tually given. It separates the nutritious 



