LECTURE III. 117 



without the expense of muscular exertion. 

 It is yellow, tough, firm, and powerfully 

 elastic. 



The spinous processes are situated so 

 far behind the centre of motion, that if they 

 had been tied together by unyielding liga- 

 ments, these must have been formed of con- 

 siderable length, to allow of the greatest de- 

 gree of bending of the column, and then they 

 would have been useless and wrinkled in 

 its common position. The elastic ligament 

 admits of the utmost motion of the column, 

 and, by its powerful elasticity, tends to 

 restore it, and retain it in its natural 

 form. The elasticity of the substance, in- 

 terposed between the bodies of the verte- 

 brae, also co-operates in restoring the co- 

 lumn to its natural figure. If we take the 

 vertebral column of a young subject sepa- 

 rately from the other parts of the skeleton, 

 and forcibly bend it in different directions, 

 we find it suddenly and forcibly recoil, and 

 assume its proper shape. The vertebral 

 column is not straight ; it comes forwards 

 in the neck and loins, so as to appear like 



I 3 



