CHAP. III. 



Of Nutrition and Groijuth. 



A N animal body is a kind of internal mould, 

 X^,. in which the nutritive matter is fo alTi- y 

 milatcd to the whole, that, without changing 

 the order or proportion of the parts, each part 

 receives an augmentation. This increafe of 

 bulk has, by fome philofophers, been called an 

 expanfion or unfolding of the parts ; becaufe 

 they fancied they had accounted for the phae- 

 nomenon, by telling us, that the form of an 

 animal in embryo was the fame as at full ma- 

 turity, and that, therefore, it was eafy to con- 

 ceive how its parts fliould be proportionally un- 

 folded and augmented by the addition of ac- 

 ceffory matter. 



But, how can wc have a clear idea of this aug- 

 mentation or expanfion, if we confidcr not the 

 bodies of animals, and each of their parts, as fo 

 jnany internal moulds which receive the accef- 

 ibry matter in the order that refults from their 

 polition and ftrudure ? This expanfion cannot 

 be efledled folely by an addition to the furfaces, 

 but, on the contrary, by an intus-fufception, or 

 by penetrating the whole mafs j for the lize of 



the 



