68 NATURAL THEOLOaY. 



CHAPTER VIII. 



OF MECHANICAL ARRANGEMENT IN THE 

 HUMAN FRAME. 



V/e proceed, therefore, to propose certain examples talcen 

 out of this class ; making choice of such as, among thosa 

 which have come to our knowledge, appear to be the most 

 striking and the best understood ; but obliged, perhaps, to 

 postpone both these recommendations to a third, that of the 

 example bemg capable of explanation without plates, or fig- 

 ures, or technical language. 



OF THE BONES. 



I. I challenge any man to produce in the joints and piv" 

 ots of the most compHcated or the most flexible machine 

 that was ever contrived, a construction more artificial, oi 

 more evidently artificial, than that which is seen in the ver- 

 tebra3 of the human neck. Tv/o things were to be done : 

 the head was to have the power of bending forward and 

 backward, as in the act of nodding, stooping, looking upward 

 or downward ; and, at the same time, of turning itself round 

 upon the body to a certain extent — the quadrant, w^e wdll 

 say, or rather, perhaps, a hundred and twenty degrees of a 

 circle. For these two purposes two distinct contrivances 

 are employed : first, the head rests immediately upon the 

 uppermost part of the vertebrae, and is united to it by a 

 /^^?^g■e -joint, upon which joint the head plays freely forward 

 and backward, as far either w^ay as is necessary, or as the 

 ligaments allow ; wliich w^as the first thing required. But 

 then the rotary motion is unprovided for ; therefore, se,?ond- 

 ly, to make the head capable of this, a further mechanism 

 is introduced — not between the head and the uppermost 

 bone of the neck, where the hinge is, but between that bone 

 and the bone next underneath it. It is a mechanism re- 

 sembling a tenon and mortise. This second, or uppermost 



