NATURAL THEOLOGY. 217 



of the body, their action, necessary exposure, and 

 irritation, would have subjected the animal to con- 

 tinual pain. General as it is, it was not the sort 

 of integument which suited the teeth ; what they 

 stood in need of was a strong, hard, insensible, 

 defensive coat ; and exactly such a covering is 

 given to them, in the ivory enamel which adheres 

 to their surface."'' 



2. The scarf-skin, which clothes all the rest of 

 the body, gives way, at the extremities of the toes 

 and fingers, to nails. A man has only to look at 

 his hand, to observe with what nicety and pre- 

 cision that covering, which extends over every 

 other part, is here superseded by a different sub- 

 stance and a different texture. Now, if either 

 the rule had been necessary, or the deviation from 

 it accidental, this eflect would not be seen. When 

 I speak of the rule being necessary, I mean the 

 formation of the skin upon the surface being pro- 

 duced by a set of causes constituted without de- 

 sign, and acting, as all ignorant causes must act, 

 by a general operation. Were this the case, no 

 account could be given of the operation being 

 suspended at the fingers' ends, or on the back 

 part of the fingers, and not on the fore part. On 

 the other hand : if the deviation were accidental, 

 an error, an anomalism — were it any thing else 

 than settled by intention — we should meet with 

 nails upon other parts of the body : they would 



*'' See the dissertation on teeth, in the Appendix. 

 19 



