﻿214 Proceedings of the Boyal PhysicaJ Society. 



placing cells to be provided for out of the blood supply of 

 the developing bone ; in other words, the indi\dduation of the 

 osteoblasts is only moderately successful, is relatively low, 

 and therefore osteogenesis is hio:h. 



"Without the scaffolding provided for them by the cartilage, 

 the osteoblasts cannot add much to the length of the bone, 

 they, therefore, add lamina after lamina to its circumferences. 

 In such conditions, as a subsidiary, and, in large measure, as 

 an accidental factor, the effects of muscle activity are felt by 

 the bone cells as determinants of areas of osteogenetic hyper- 

 activity. The areas of myo-osseous and tendino-osseous 

 articulation are in a sense areas of irritation, the contraction 

 and relaxation of the muscle imposing intermittent strain 

 upon the periosteum, which, in turn, through the application 

 of a well-known physio-pathological law is known to lead to 

 increased vascularitv. The increased vascularity increases 

 the available supply of nutriment, and leads to a particularly 

 active euryplasia in the areas of myo-osseous articula- 

 tion. 



Further, the more intense within limits the general food 

 shortage is, the more intense will be the osteogenetic activity ; 

 because, as the success of individuation diminishes, the 

 activitv of genesis increases. 



The conclusion, therefore, is that smooth and graceful bones 

 are associated with favourable nutritive conditions, with free 

 endochondral ossification; that rugged, strongly-marked bones 

 are associated with what are, from the point of view of the 

 celh relatively unfavourable nutritive conditions, with free 

 periosteal ossification. 



(d) The Metaholism of the Male compared with the Meta^ 

 holism of the Female. — The expenditure of energy by the male 

 is normally greater than the expenditure of energy by the 

 female, and as a result the metabolism of the male is normally 

 more vigorous, more katabolic, than that of the female. The 

 proof of this statement is wide-based on physiological, 

 psychical, and biological facts, and I propose to hold it as, in 

 the main, established. 



It is now possible to state, in terms of metabolism, the 



