382 INFLAMMA TION. 



this knowledge, strange as it may appear. Through the kind- 

 ness of Dr. J. Lewis Smith, of New York City, I obtained two 

 fractured arm-bones of children, one of fourteen days', the other 

 of about four weeks', standing. I learned from these specimens 

 that the process of healing is in human bones identical with that 

 observed in animals. 



Upon fracturing the bones of an animal, hemorrhage is pro- 

 duced, on account of the rupture of blood-vessels in surrounding 

 tissues, as well as those of the bone ; the initial swelling of the 

 tissues around the place of injury is known to surgeons to be 

 due to the extravasation of blood. The subsequent fate of the 

 extravated blood-corpuscles we do not know ; what we call 

 " absorption " of the blood is merely an expression of ignorance. 



In the first few days following the injury inflammation sets 

 in, varying in intensity with the degree of displacement of the 

 ends of the fractured bone, and the general constitution of the 

 animal operated upon. The inflammatory process is most active 

 in the tissues which have the most abundant vascular supply 

 i. e.y the outer layer of the periosteum and the ruptured muscles, 

 while it is less marked in the central medullary tissue of the 

 bone, and still less in its compact portions. 



The result of the inflammation, as described in former arti- 

 cles, is that the involved tissues, and mainly the periosteum, 

 break down into medullary corpuscles, the same formation which 

 originally contributed to produce the periosteal tissue. By an 

 outgrowth of living matter, new medullary or inflammatory 

 elements are afterward produced, all of which remaining in 

 uninterrupted connection represent the inflammatory new forma- 

 tion. The compact bone-tissue, in the immediate vicinity of the 

 fracture, is also melted out, and on the eighth day we see medul- 

 lary spaces, which are more or less numerous, and filled with 

 medullary or inflammatory corpuscles. These corpuscles are con- 

 nected with the inflammatory tissue arising from the periosteum 

 and the central marrow. 



In the second week the inflammatory elements, being identi- 

 cal with medullary or embryonal corpuscles, form a new tissue, 

 in a manner already dwelt upon in the chapter on formation of 

 connective tissue. The result of tissue formation in this case is 

 again identical with that observed in the earliest stages of 

 embryonal life i. e., the medullary tissue is transformed into 

 cartilage. Cartilage tissue appears after fractures, both of the 

 human and animal bones, and constitutes the provisional callus of 



