WILLIAM ROUX'S THEORY 171 



pearing where it occurs. Bones submitted to a greater 

 strain than they should normally sustain have been 

 observed to assume, owing to functional stimulation, 

 a much greater development. A seven-year-old boy 

 had, on account of osteomyelitis, almost completely 

 lost the shaft of his tibia, the only thing left being a 

 spur a few inches long which was a continuation of 

 the upper apophysis. Poirier tried to replace the tibia 

 by the fibula by resetting the latter and uniting it to 

 the lower apophysis of the missing tibia. Fifteen 

 months later the fibula had trebled in size and had com- 

 pletely replaced the tibia. 1 In another case the weld- 

 ing of bones effected itself naturally in an adult indi- 

 vidual. Owing to a disease which affected the patient 

 in childhood the head of the tibia became separated 

 from its diaphysis and became welded to the fibula. 

 The latter bone grew and when the patient, then fifty- 

 five years old, was examined, both bones were of the 

 same size. 2 



Cope cites two similar cases of luxated elbow joint, 

 one in a man and the other in a horse. Friction elim- 

 inated the bony tissue at the point of contact and an 

 articular surface appeared. 3 



1 Poirier. Rapport au Congres de Chirurgie (1896) sur le remplace- 

 ment d'une diaphyse tibiale d6truite par Vosteomy4lite par la dtaphyse 

 peroniere. 



2 Communicated by S. Ledttc to the editor-in-chief of V Annie biolo- 

 gique and reported in Vol. II of that publication. 



3 Proceed, of the Amer. Philos. Soc, 1892, cited by Cope in Primary 

 Factors of Organic Evolution, p. 277. 



