478 



LECTURE XIX. 



bones are always infractions,* those of the epiphyses are 

 due to the proliferation of the cartilage and constitute 

 simple inflexions ; and it is easy to conceive that parts, 

 which are so entirely deprived of their regular develop- 

 ment (as they are in rickets), and ought, properly, to be 

 densely impregnated with calcareous salts, must retain 

 great mobility. 



FIG. 133. 



Fig. 133. Vertical section of cartilage from the diaphysis of a ricketty, growing 

 tibia from a child two years old. A large conical process of medullary tissue, send- 

 ing out a lateral band on the left side, extends from m up into the cartilage ; it con- 

 sists of fibrous basis-substance with spindle-shaped cells. At the circumference, at 

 c, c, c the cartilage in a state of proliferation with large cells and groups of cells; 

 at c', c' commencing thickening and internal indentation of the cartilage-capsules 

 which at o, o coalesce and form osteoid tissue. 300 diameters. 



* By infraction I understand an incomplete fracture (solution of continuity) within 

 the periosteum, which remains intact. From a MS. Note by the Author. 



