216 NATURAL THEOLOGY. 



their own accord. Now let it be remembered, 

 that this is the position of the limbs in which the 

 bird rests upon its perch. And in this position it 

 sleeps in safety ; for the claws do their office in 

 keeping hold of the support — not by any exertion 

 of voluntary power, which sleep might suspend, 

 but by the traction of the tendons in consequence 

 of the attitude which the legs and thighs take by 

 the bird sitting down, and to which the mere 

 weight of the body gives the force that is neces- 

 sary. 



VI. Regarding the human body as a mass ; re- 

 garding the general conformations which obtain 

 in it ; regarding also particular parts in respect to 

 those conformations ; we shall be led to observe 

 what I call " interrupted analogies." The follow- 

 ing are examples of what 1 mean by these terms ; 

 and I do not know how such critical deviations 

 can, by any possible hypothesis, be accounted for 

 without design: — 



I. All the bones of the body are covered with a 

 periostium, except the teeth, where it ceases; and 

 an enamel of ivory, which saws and files will 

 hardly touch, comes into its place. No one can 

 doubt of the use and propriety of this difference ; 

 of the " analogy " being thus "interrupted ;" of the 

 rule, which belongs to the confirmation of the 

 bones stopping where it does stop ; for, had so ex- 

 quisitely sensible a membrane as the periostium 

 invested the teeth, as it invests every other bone 



