162 SEPARATION OF BONE. 



matter in this minutely disintegrated state are so 

 very small that the fluid containing them in suspen- 

 sion would exhibit the same properties as that in 

 which small particles were actually dissolved, for the 

 particles in suspension would traverse animal mem- 

 brane with the fluid, and would be brought into suf- 

 ficiently intimate contact with the bioplasm to be 

 taken up and appropriated by the living matter itself. 

 By this farther change particles do become chemically 

 altered, and the constituent elements separated from 

 one another and prepared for recombinations and the 

 formation of substances, it may be, of a kind totally 

 different from those which existed before. 



221. Reparation of bone. The great importance 

 of this subject to the surgeon has led to many very 

 interesting researches. From the time of Duhamel 

 to the present day, the several steps of the process 

 by which new bone is formed have been ably elu- 

 cidated in all that relates to their more obvious 

 characters by the investigation of distinguished 

 scientific men and practitioners. "When a fracture 

 occurs, blood is, of course, effused into the wound, 

 both from the ruptured vessels of the bone itself, and 

 from those of the surrounding structures participating 

 in the injury. This blood soon undergoes change. 

 Its colouring matter is absorbed, and its bioplasm 

 particles (white blood corpuscles) multiply. The 

 fibrin at length disappears, being appropriated 

 by the developing bioplasts, and in its place a 

 form of fibrous tissue is produced. This at length 

 undergoes calcification, and from the fourth to 

 the sixth week a soft temporary bone, termed by 

 Dupuytren provisional callus, results. This is slowly 

 replaced by the development of permanent bone 

 {permanent callus) from the growth and multiplica- 

 tion of the bioplasts of the torn periosteum of the 

 original bone. 



222. Of inflammation of bone. In the develop- 



