BONE, PATHOLOGICAL CONDITIONS OF. 



445 



gether. This fluid, which was termed the osse- 

 ous juice, was supposed to acquire the requi- 

 site consistence afterwards, and thus became 

 the medium of a firm union. Nothing, how- 

 ever, was said of the time or manner in which 

 the consolidation was effected, nor of the 

 absorption of the superabundant part of this 

 fluid subsequently. 



The first who doubted this theory of the 

 osseous juice, or rather who thought it insuffi- 

 cient, was Duhamel, a man of extraordinary 

 ingenuity, but unfortunately not a physician, 

 and therefore not qualified to examine or to 

 explain the results of vital actions. lie adopted 

 his ideas as to the formation and growth of 

 bone analogically from trees and vegetables, 

 and supposing the periosteum to answer the 

 same purpose to bone that the bark did to the 

 wood, he conceived that ossification went for- 

 ward by the conversion of the internal layer of 

 periosteum into bone. It was natural, having 

 formed this theory as to the original conforma- 

 tion, to advance it still farther into an explana- 

 tion of the mode of re-union in fracture. He 

 said that the extremities of the torn periosteum 

 covering the fragments swelled ; that they met, 

 and uniting, formed a kind of brace or ferule 

 inside and outside of the fracture; sometimes, 

 in case of the external membrane being torn 

 off, the internal answered every purpose alone; 

 sometimes the external periosteum was suffi- 

 cient, but in every case it was this that perfected 

 the operation. It is needless now to canvass 

 a theory that has long since been given up as 

 untenable, yet as if to show how little of 

 novelty can be expected in physiological rea- 

 soning, it will be found that an opinion not 

 very far removed from this in its bearings was 

 the one entertained by Dupuytren, so recently 

 lost to science. 



The next opinion to be noticed is that of 

 Haller. This great physiologist, who was a 

 cotemporary of Duhamel,* quite dissatisfied 

 with the ideas entertained in his time on this 

 subject, endeavoured to develope the truth by 

 experiments, and conducted many, in conjunc- 

 tion with a pupil of his named Dethlef. The 

 result was, that the process of re-union ap- 

 peared to him to be the same as that of the 

 original ossification; 1st, that a gelatinous or 

 gluey substance is poured out around the ends 

 of the fragments; 2d, that this substance be- 

 comes converted into genuine cartilage; and 

 lastly, that an osseous deposit is laid down in 

 the cartilage, forms a ring of bone, and gra- 

 dually increases until the entire ossification is 

 completed. This theory is principally objec- 

 tionable in the regularity with which these 

 changes are said to take place, whereas it is 

 more than questionable whether this gelatinous 

 fluid, the origin of the callus, ever becomes car- 

 tilage at all. Doubtless it is altered in con- 

 sistence and becomes hard and firm, opaque 

 and elastic, and thus far resembles cartilage in 

 its sensible qualities;! but it is tinged of a red 



* Haller was born a short time after Duhamel, 

 and died before him, this latter philosopher having 

 attained the age of 82. 



t Macdonald. 



colour by feeding the animal with madder, 

 which is not the case with cartilage ; and che- 

 mical analysis shews its nature to be osseous 

 and not cartilaginous. However, the experi- 

 ments of Haller and Dethlef are entitled to 

 great attention from the care with which they 

 were conducted, and with a little modification 

 their results are probably not very remote from 

 truth. 



Hunter, so happy in the doctrine of adhe- 

 sion, endeavoured to extend it as widely as 

 possible, and has certainly simplified both our 

 notions with respect to divided parts and our 

 practice in procuring union, although his cor- 

 rectness in considering effused blood to be the 

 medium of that union has been frequently 

 doubted. According to him, the first effect of 

 fracture is, the effusion of blood from the 

 ruptured vessels of the bone and the adjacent 

 structures: this blood becomes organised by 

 vessels shooting into it ; whilst in the mean 

 time the ends of the fragments inflame, and 

 this inflammation produces adhesion in the 

 surfaces that are even, and a disposition in the 

 scales or points of the broken edges that re- 

 main, to be removed by absorption. Pretty 

 nearly the same are the conclusions to which 

 Mr. Howship arrived after a series of expe- 

 riments conducted with great accuracy and 

 minuteness. This paper is in the ninth volume 

 of the Medico-Chirurgical Transactions, in 

 which these experiments (performed on the 

 fractured bones of rabbits) are detailed and 

 illustrated with engravings. They refer to the 

 appearances observed on the third day, on the 

 fifth, the ninth, the fifteenth, the twenty-third, 

 and thirty-second days after the fracture. The 

 relation of these experiments singly would 

 occupy more space than can be appropriated to 

 this part of the subject, and we must therefore 

 confine ourselves to the conclusions as drawn 

 from them by the author himself. He concludes 

 that the first effect of fracture is extravasation 

 of blood into the surrounding cellular struc- 

 tures, principally that of the periosteum ; into 

 the medullary cavities of both fragments and 

 between their fractured extremities. This blood 

 soon coagulates ; after some further time its 

 colouring matter disappears ; and the thick- 

 ened periosteum becoming more firm assumes 

 the sensible characters of cartilage. The de- 

 position of osseous matter takes place within 

 the coagulum, beginning at the part nearest the 

 fracture and extending gradually from this 

 point: it even commences in the clot situated 

 within the medullary cavity before the colour- 

 ing matter is removed ; but under every cir- 

 cumstance and in every situation, we are to 

 understand that the coagulum of blood is the 

 nidus of ossification and the medium of union 

 between the fragments. Notwithstanding the 

 respect due to such high authority, there are 

 many who do not believe in the possibility of 

 effused blood becoming organised, and look 

 with doubt and suspicion on every experiment 

 and every observation by which such a doc- 

 trine is sought to be established. They reason, 

 that if, under any circumstances, blood became 

 the medium of union, we ought to leave the 



