THE OSSEOUS SYSTEM. 383 



perceptions, but in any case the painful impressions are 

 conveyed, be identical with those through which the reflex 

 actions, above referred to, are carried on, is not determined; but, 

 looking at the origin of most of the bone-nerves from the 

 cerebro-spinal nerves, such an opinion might perhaps be main- 

 tained, it being premised that the connections of the nerves 

 with the brain are to be regarded as less intimate than in the 

 case, for instance, of the cutaneous nerves. I would, in 

 addition, call attention to the remarkable occurrence of nerves 

 in the cartilage of the septum narium in the Calf, although 

 I am unable to say anything more with respect to their nature 

 than with regard to that of the nerves of bone. 



[On the subject of the numerous pathological changes which 

 occur in the bones, only some brief remarks can here be made. 

 Fractures readily unite, under but moderately favorable circum- 

 stances, by true bone-substance, which, in the cylindrical bones 

 of animals is preceded by the formation of a true cartilage, a 

 fact of which I and others are satisfied ; whilst, according to 

 Paget, this rarely appears to be the case in man. In the 

 spongy bones, in fractures within the articular capsules, and 

 under unfavorable circumstances, the fractured ends frequently 

 unite merely by a fibrous callus, a sort of articulation being 

 formed between them. After loss of substance the osseous 

 tissue is readily regenerated ; and it is the periosteum especially, 

 which, in this case, as in the growth of a bone in thickness, 

 plays the principal part in the restoration ; of course by 

 means of the exudation poured out from its vessels. In 

 animals, entire bones of the extremities, and ribs are rege- 

 nerated, pretty nearly in their original figure, not only when 

 the periosteum has been saved, of which many examples are 

 exhibited in Heine's collection in Wurzburg, but even after 

 entire excision with the periosteum, a rudiment of the bone is 

 reproduced (Heine). In man also, a good many instances 

 have been afforded of the reproduction of entire bones, such as 

 the lower jaw, the ribs, the scapula (Chopart); and the cases of 

 isolated, — in some instances large, portions of bone being so 

 regenerated are very numerous. It is especially the diaphyses, 

 which are readily replaced, when they have been lost in one 

 way or another, less frequently the spongy bones and spongy 



