REGARDED AS A MASS. 121 



the knee joint bending backward, the hip joint forward ; 

 the flexibility, in every direction, of the spine, especially 

 in the loins and neck, appear to be of great moment in 

 preserving the equilibrium of the body. With respect to this 

 last circumstance it is observable, that the vertebrae are so 

 confined by ligaments as to allow no more slipping upon their 

 bases, than what is just sufficient to break the shock which 

 any violent motion may occasion to the body. A certain 

 degree also of tension of the sinews appears to be essential 

 to an erect posture ; for it is by the loss of this, that the 

 dead or paralytic body drops down. The whole is a won- 

 derful result of combined powers, and of very complicated 

 operations. 



We have said that this property is the most worthy of 

 observation in the human body : but a bird, resting upon 

 its perch, or hopping upon a spray, affords no mean speci- 

 men of the same faculty. A chicken runs off as soon as it 

 is hatched from the egg ; yet a chicken, considered geo- 

 metrically, and with relation to its centre of gravity, its 

 line of direction, and its equilibrium, is a very irregular 

 solid. Is this gift, therefore, or instruction ? May it not 

 be said to be with great attention, that nature hath balanc- 

 ed the body upon its pivots 1 



I observe also in the same bird a piece of useful me- 

 chanism of this kind. In the trussingof a fowl, upon bend* 

 ing the legs and thighs up towards the body, the cook find's 

 that the claws close of their own accord. Now let it be 

 remembered, that this is the position of the limbs, in which 

 the bird rests upon it 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 necessary. 



VI. Regarding the human body as a mass ; regarding 

 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 following are examples of what I mean by these terms : 

 and I do not know how such critical deviations can, by 

 any possible hypothesis, be accounted for, without design. 



1. All the bones of the body are covered with a pGri- 

 osteum, except the teeth ; where it ceases, and an enamel 

 of ivory, which saw^ ^nd files will hardly touch; comes inta 



