264 JOHN C. KOCH 



the area occupied by the spongy bone increases the thickness of 

 the shell of compact bone decreases, finally reaching a minimum 

 in section 75. 



In sections 68 to 75 two systems of trabeculae are seen: 

 one consisting of lines paralleling on either side of the center, 

 the lateral and medial margins of the sections; the other, a sys- 



Fig 26 Sagittal mid-section of distal end of femur. This is taken from the 

 dissecting room specimen of normal structure, the upper end of which is shown 

 in figure 23. (Natural size.) 



