SYSTEMATIC SYNTHESIS OF TISSUES INTO ORGANS. 219 



down the front surface of the bodies of the vertebrae to 

 the very extremity of the coxcyx (see Fig. 6, PI. 16), 

 and another is found on the back face of the bodies, that 

 is, within the canal. Several others exist, of minor im- 

 portance. 



338. Thus THE SPINAL COLUMN FINISHED stands be- 

 fore us one of the most admirable pieces of mechanism 

 the mind can contemplate, exceedingly strong yet beau- 

 tifully elastic by means of its curvatures and cushions, 

 securely protecting, at the same time, in its flexible 

 canal the vital spinal cord, and affording, though so neat 

 and compact, ample surface for the attachment of all 

 the ligaments and tendons that are adapted to produce 

 or limit its motions. Resting upon it, the head is carried 

 without ajar; and hanging upon it, all the delicate vital 

 organs enclosed in the walls of the trunk are carried 

 with equal safety. 



339. THE RIBS, 12 in number (sometimes 10, some- 

 times 14), SERVE the purpose of levers in controlling 

 motions of the spinal column, and as a framework to 

 enclose and protect the organs of the Chest. 



340. THE RIBS ARE CONSTRUCTED with very irregular 

 forms, and singularly adapted by their peculiarities to 

 be strong, while at the same time they are very light. 



341. THE RIBS ARE ATTACHED by a head to a socket, 

 formed in the back part of the sides of the bodies of each 



Describe Fig. 5, PL 1 6. Write table of Div. Write 2d table. 338. What said ? 

 9. What do ? 840. How ? 341. How ? 



