Regeneration of Bone from Periosteum. 57 



We were unable in our work to parallel German's results in the 

 case of all the species which he claims produce creatinine. This 

 we believe to be due to the fact that the ability to produce crea- 

 tinine is a characteristic which may easily be lost by bacteria 

 just as is the power of producing indol. 



41 (737) 



Regeneration of bone from periosteum. 

 By S. L. Haas. 



[From the Pathological Laboratory of Stanford University.] 



In an endeavor to establish the factor that periosteum plays 

 in the regeneration of bone, the following experiments were per- 

 formed on the ribs of rabbits. 



Several experiments consisting merely of a subperiosteal re- 

 section of the rib showed after 20 days a cartilaginous-like material 

 filling the entire space; while after a longer time complete filling 

 in with bone. 



The next endeavor was to isolate the periosteum so as to 

 prevent bony elements from growing in to the periosteal space. 



In one experiment the rib ends were capped with lead — after 

 12 days no evidence of regeneration. This method was discarded 

 as it was thought better to try and raise the rib from its periosteal 

 covering without severing the ends, and isolate it by sewing muscle 

 beneath the raised rib. 



In 10 experiments of this nature the results uniformly showed 

 a tendency for bone to grow in at the angle where the rib was 

 raised from its periosteal bed. In one experiment after 59 days 

 the whole area was filled in by bone, although in another after 

 8 months there was only a small spicule of bone growing in at the 

 sternal side. In only one experiment after 26 days was an isolated 

 island of bone found, free from connection with bone elements. 



Although this does not prove the point sought, it at least 

 emphasizes the tendency of bone to grow in the direction of existing 

 periosteum. 



At this stage it was noticed that there was a difference at 

 times in bone regeneration and it was suggested to try the effect 



