44 



GENERAL ANALYSIS. 



quite fills the ca- FIG. 68. 



nal throughout 

 the spinal col- 

 umn. 



75. WHEN 

 THE SPINAL COL- 

 UMN IS FLEXED, 



the central canal 

 is lessened, and 

 apart of the fluid 

 within is instant- 

 ly pressed up into 

 cushion beneath the 

 brain, holding it firm- 

 ly, as in a vice, but 

 with the gentleness of 

 an infant. 



76. THE PROTEC- 

 TIONS OF THE BRAIN 

 from jars, found in the 

 three members, the 

 neck, trunk, and lower 

 extremities, are: (1st) 

 the elastic springs, 

 cushions, gristles or 

 cartilages of the spinal 

 column; (2d) the fluid 

 of the spinal canal ; 

 (3d) the marrow in 



FIFTH MEMBER OF THE BODY. 



77. THE MIND NEXT REQUIRES means for handling 

 the various objects of its regard. These means are fur- 

 nished in the upper extremities. 



78. THE UPPER EXTREMITIES are levers of a some- 

 what more complex structure than the lower extremities, 



the bones; (4th) 

 the gristle of 

 the joints; (5th) 

 the curvatures 

 of the column, 

 pelvis, and the 

 bones of the ex- 

 tremities ; and 

 (6th) the bend- 

 ing of the limbs 

 at the joints. 



Fig. 68 is a plan of a sec- 

 tion of the Head and spinal 

 column. C, the large brain, c, 

 the small brain, and sc, spinal 

 cord ; a a is intended to convey 

 a good idea of the fluid-filled 

 cushion beneath the Brain 

 and around the spinal cord 

 for its whole length, except at 

 points where nerves leave it. 

 The fluid will always move 

 more quickly than the less fluid 

 Brain, and of course will, in 

 case of rapid motion of the 

 head, be impelled into that 

 part of the cushion against 

 which the brain will be thrown, 

 and thus the cushion will al- 

 ways be thickest where the 

 thickness is most needed. 



75. What effect - ? 

 78. What are - 



Describe Fig. 68. 76. What are - ? 77. What does - ? 



