130 COMPARISONS OF STRUCTURE IN ANIMALS. 



forwards, backwards, or laterally to a greater 

 or less degree, without an abrupt angle occur- 

 ing in any part, to the injurious pressure of 

 the spinal cord. The flexure is always formed 

 by the concurrence of many vertebree, and not 

 of two, and the arch formed is gradual. Thus 

 the hedgehog or the dormouse may roU itself 

 tip into a ball, without disturbing the great 

 cord of nervous communication between the 

 trunk and the brain. In man, who stands 

 erect, the head is nearly balanced upon the 

 spine ; and thus he gazes around him, 

 " monarch of all " he surveys ; but his spine 

 is not a straight column like a ruler, for then, 

 though erect, his form would be destitute of 

 grace, and his movements would be stiff and 

 ungainly. It presents a series of graceful 

 curves, that convert it into a perfect spring. 

 The neck gently arches forwards, and thence 

 between the shoulders takes a slight curve in 

 the opposite direction, and again arches for- 

 ward along the region of the loins. The 

 vertebra of the loins are the largest, those 

 of the neck the smallest, and seven in 

 number ; and as the head is balanced, or 

 nearly so, on the spine, requiring no strong 

 muscles to sustain its weight, the processes of 



