390 GENERAL ANATOMY. 



ciple, have admitted that the fragments are united by a gluti- 

 nous or coagulable matter. 



J. Hunter, Macdonald, and Howship, have thought that this 

 organizable and agglutinating matter is furnished by the blood. 

 It is well known that Duhamel and Fougeroux have admit- 

 ted that the periosteum furnishes a bony ring which unites the 

 fragments. Blumenbach has given the figure of a human bone 

 surrounded by a ring of this kind. M. Pelletan taught the 

 same thing in his clinical lectures. Camper had observed that 

 there are an external callus and an internal callus. Bichat, 

 M. Dupuytren, M. Cruveilher, and others, have admitted that 

 these external and internal ossifications are provisory. 



Many pathologists,and especially Bordenave, Bichat, Riche- 

 rand, Scarpa, &c. have maintained that the union of divided 

 bones is effected by cellular and vascular granulations, like that 

 of the soft parts, which is true in either case only where the 

 division is external and suppurative, and not when it takes 

 place, as well as the union, without external wound and with- 

 out suppuration. 



1 have already elsewhere* remarked, that all that these hy- 

 potheses want, in order to be theories or exact expression of 

 facts, is to be combined, or not to be exclusive. This was 

 Troja's opinion, and is also that of M. Boyer, M. Delpech, &c. 

 In fact, in the uniting of a simple fracture, there take place 

 in succession, agglutination of the fragments by an organizable 

 fluid, the materials of which are furnished by the blood; ossi- 

 fication of a similar substance, infiltrated all round the frac- 

 ture, both internally and externally; lastly, vascular and osse- 

 ous union between the fragments themselves. 



The periosteum, which, when it exists, appears to perform 

 so important a part in the production of the callus, is no more 

 indispensable here than in the reproduction after necrosis. It 

 has been removed from the ends of fractured bones in birds, 

 and has been reproduced at the same time that the callus 

 formed. 

 Comminuted fracture of the long bones, and especially that 



* A. Beclard, Propositions sur quelques Points dc la Alcdecine, Paris, 1813. 



