from Dr. Thornton. ■ 227 



be able to do it when it is pressed into the kings with any 

 force, even a greater than is sufficient to swell the air- 

 vessels to their usual magnitudes : and therefore animals do 

 not die in a confined air, from the vesiculce not being suf- 

 ficiently dilated on account of a diminution of the elasticity 

 of the air. A diminution of the elasticity of the air is no 

 otherwise hurtful than as it hinders the vesicles from being 

 sufficiently dilated, and thereby hinders the blood from re- 

 ceiving its usual quantity of acid in a given time ; on which 

 account the blood will not be sufficiently dissolved and 

 warmed in the lungs j which will make respiration quick 

 and uneasy, but cannot cause sudden death." , 



His xxviith Proposition is, — *' The noiirishment of animals 

 changes its texture in their bodies tilt it becomes like their 

 solid and durable parts. 



" For the solid and durable parts of animal bodies grow- 

 out of their nourishment ; ,but their growth is from an ad- 

 dition and adhesiou of like parts, and therefore the nourish- 

 ment of animals changes its texture in their bodies till it 

 becomes like their solid and durable parts. 



^' Cor. 1 . Hence it appears that animals will not be rightly 

 nourished when their nourishment does not change its tex- 

 ture in their bodies till it becomes like their solid and dura- 

 ble parts. 



" Cor. 2. Hence it appears that the nourishment, by 

 changing its texture in the bodies of animals, becomes 

 more drv and earthy than it was before, otherwise it would 

 not be like their solid and durable parts, 



" Proposition xxviii. — The tertiire of the nourishment is 

 changed in the bodies of, animals by a gentle heat and motion. 



" The first remarkable change in the texture of the nou- 

 rishment is made in the stomach : in this bowel the solid 

 parts of the food are dissolved and intimately mixed with 

 the fluids. This mixture is usually called chyle. 



" Some, from observing that fluids have a power of dis- 

 solving bodies, have thought that a fluid in the stomach 

 dissolves the food and turns it into chyle; but as it does 

 not appear from experiments and observations that there is 

 a fluid in the stomach endued with such a power, this opi- 

 nion is without foundation. 



" Others, from observing the great strength of the giz- 

 zards of fowls, and tluit there is ommonly (iravel found iu 

 ihcni, have imagined that the food is dissolved in the sto- 

 machs of fowls, and consequently i'l the stomachs of all 

 ;iniuials, by attrition or grinding. But if this opinion be 

 examined, it will likewise appear to be withoui; foundation: 

 for the food of fow Is is mostly grain, all sorts of which are 

 P 2 liard 



