170 NATURAL THEOLOGY. 



not BO This is the fact with respect to the human mouth . 

 the fact also is, that the parts ahove enumerated are called 

 into use from the beginning ; whereas the teeth would be 

 only so many obstacles and amioyances if they were thtre. 

 When a contrary order is necessary, a contrary order pro- 

 vails. In the worm of the beetle, as hatched from the egg, 

 the teeth are the first things which arrive at perfection. 

 The insect begins to gnaw as soon as it escapes from the 

 shell, though its other parts be only gradually advancing to 

 their maturity. 



What has been observed of the teeth, is true of the horns 

 of animals ; and for the same reason. The horn of a calf or 

 a lamb does not bud, or at least does not sprout to any con- 

 siderable length, until the animal be capable of browsing 

 upon its pasture, because such a substance upon the fore- 

 head of the young animal would very much incommode the 

 teat of the dam in the office of giving suck. 



But in the case of the teeth, of the human teeth at least, 

 the prospective contrivance looks still further. A succession 

 of crops is provided, and provided from the beginning — a sec- 

 ond tier being originally formed beneath the first, which do 

 not come into use till several years afterwards. And this 

 double or supplementary provision meets a difficulty in the 

 mechanism of the mouth, which would have appeared almost 

 insurmountable. The expansion of the jaw — the conse- 

 quence of the proportionable growth of the animal and of its 

 skull — necessarily separates the teeth of the first set, how- 

 ever compactly disposed, to a distance from one another, 

 which would be very inconvenient. In due time, therefore, 

 that is, when the jaw has attained a great part of its dimen- 

 nions, a new set of teeth springs up — loosening and pushing 

 uut the old ones before them — more exactly fitted to tha 

 space which they are to cccupy, and rising also in such close 

 ranks as to allow for any extension of line which the subse- 

 quent enlargement of the head may occasion. 



II. It is not veiy easy to conceive a more evidently pro- 



