THE GROWTH OF BONE 65 



in their new surroundings. It is significant that 

 these cases have become common only since the 

 modern treatment by massage and movements 

 has been introduced, excellent as it is when suitably 

 applied. If the periosteum had remained intact, this 

 could never have occurred. The treatment, if such 

 a lump forms, is not excision, which usually leads 

 to recurrence, but strict limitation of movement by 

 means of a splint. 



The reason why so much more callus forms in 

 animals than in man is because so much more 

 movement of the broken ends takes place. In these 

 circumstances there is often a stage in which cartilage 

 is to be found in the callus, on its way to form bone. 



It is evident, therefore, that care should be exer- 

 cised, after a fracture in which it is probable that the 

 periosteum is torn, to avoid deep massage and move- 

 ments close to the site of the fracture during the first 

 fortnight, although they may well be applied to the 

 neighbouring joints. When the fracture is very near 

 a joint it is far better to trust to a single efficient 

 movement once a week (to avoid adhesions) than to 

 allow repeated small movements in the early stages. 



It is well known that exostoses or spurs of bone 

 usually form in the attachment of muscles or tendons. 

 The probable explanation is that by the continual 

 drag and, it may be, slight wrenches, some osteo- 

 blasts are detached from the bone and invade the 

 tendon. 



Universal myositis ossificans, such as occurs in a 

 so-called " brittle man," may be due to some such 

 cause as this, or perhaps to embolism of osteoblasts. 



5 



