78 



PHYSIOLOGY. 



A vertebra of the loins ; a, a, their bodies, larger and more spongy 

 than those of the others ; b, b, 6, the superior ; c, c, c, the inferior ar- 

 ticular processes, strong and deep, the superior concave ; the inferior 

 convex ; d, d, d, the transverse processes, small and long, serving as 

 levers for the attachment of muscles ; e, e, the spinous processes, 

 strong, horizontal, and flattened at the sides; /, the spinal foramen. 



28. The vertebrae, as I have stated, are not in contact, 

 but separated by a considerable interval, which is filled by a 

 peculiar gristly substance of a highly elastic nature, which 

 is pressed out from betwixt the bones, and therefore permits 

 them to approach, and play a little in the motions of the 

 body. This compressible cushion of cartilage and ligament 

 serves indeed the triple purpose of uniting the bones to each 

 other, of diminishing and diffusing the shock in walking or 

 leaping, and of admitting a greater extent of motion than if 

 the bones were in more immediate contact. These separate 

 vertebras are firmly bound to each other in such a way as to 



