The Osseous System 347 



a few instances true ossific union may take place, more especially 

 when the periosteum is carried over with it, but in most cases the 

 same results were obtained as in heteroplasty. 



Schmitt removed a portion of the ulna one and one-half com. 

 in length and in its place transplanted a piece of bone from another 

 dog. Complete bony union took place on one side and fibrous union 

 on the other. No absorption was apparent and the vitality of the 

 implanted portion seemed to be rnaintained by thickening of its 

 periosteum. 



Only when autoplasty {i. e., where implanted portions were 

 taken from the same individual) was practiced, was there indication 

 of true union, and this was made more certain when the periosteum 

 remained adherent or flaps were left intact at the site of operation. 

 Even in this case there were signs of absorption. 



All the above operations were done strictly aseptically. When 

 the parts were not rendered fully aseptic, they suppurated and ex- 

 truded- the implanted portions. Thus it became evident that re- 

 generation of bone can only take place from periosteum, and where 

 the latter is entirely removed no true ossification can follow. A 

 displaced fragment, when replaced, must have connection with 

 periosteum which in turn is in vital condition either by connection 

 with neighboring periosteum or adjacent tissues. Hence the sur- 

 geon aims to conserve the periosteum to secure its bone-constructive 

 power. 



The periosteum is capable of remarkable vitality, for it may live 

 and produce bone after its transplantation into an animal of a dif- 

 ferent species. Trueheart recorded a case of a man in which he 

 grafted pieces of periosteum to restore the middle third of a clavicle 

 which had been shot away. Fresh transplants were inserted three 

 times a month for two months when two and three-fourths inches 

 of bone had been produced. The periosteum was from newly- 

 killed dogs. A novel method was pursued by Rydygier. He tried 

 separating flaps from the periosteum just above a pseudarthrodic 

 defect, except at the border where it remained attached, turning 

 them over so that the inner side lay outwards and vice versa, and 

 laid them over the false tissue. Good results were achieved, but 

 Schmitt who repeated the experiments, failed, on account of the 

 movements of the animals, which could not wholly be restrained, 

 tearing out the flaps. Schmitt then resected a piece of a long bone 



