BONE, PATHOLOGICAL CONDITIONS OF. 



444 



and the surrounding soft parts affords the 

 strongest grounds for believing that the minute 

 vascular and membranous organization of the 

 bones is as susceptible of impressions from 

 irritation or sympathy as the muscular, glandu- 

 lar, or other soft structures of the body." The 

 bones in common with other parts are conse- 

 quently subject to inflammation with all its 

 consequences of adhesion, suppuration, granu- 

 lation, ulceration, &c. &c., but subject to the 

 following modifications which result from the 

 peculiarities of structure and material compo- 

 sition indicated, and the intimate connexion 

 just alluded to between them and the adjacent 

 soft parts. 



1. The connexion between the bone and 

 periosteum is so complete that it is not easy to 

 conceive how inflammation of a bone can occur 

 without its membranes being more or less en- 

 gaged, and therefore it is difficult to meet with 

 a case of diseased bone unaccompanied by 

 periostitis. 



2. The effects of inflammation on the mem- 

 brane and on the bone must be different. One 

 structure can swell, the other in the first in- 

 stance cannot; and hence the vessels of the 

 bone itself in a state of debility and compressed 

 by an unyielding substance are very liable to 

 die, whilst those of the periosteum tumefy and 

 exhibit a more mitigated form of disease. 

 Thus the periosteum in inflammation is gene- 

 rally found swollen or thickened, and detached 

 from the bone underneath, which is then usually 

 either carious or necrosed. 



3. Those bones or parts of bones which are 

 hardest and firmest usually die soonest, whence 

 Mr. Wilson's remark that " they are the soonest 

 cured," the process of exfoliation being set up 

 by the surrounding living parts in order to 

 remove that which is dead. 



4. In the various processes of repair and re- 

 production the periosteum largely participates, 

 and if this latter membrane has been injured 

 or torn off, the vessels of the adjacent cellular 

 tissue seem to assume a new function in order 

 to supply its place. Thus, if a portion of the 

 scalp is torn down, leaving the cranium per- 

 fectly denuded, it by no means follows that 

 the bone must exfoliate if the flap has been 

 carefully laid down and still preserves its 

 vitality ; but perhaps the best illustration may 

 be drawn from some cases of necrosis succeed- 

 ing to injuries by which the periosteum had 

 been removed, in which the process of regene- 

 ration is commenced and completed notwith- 

 standing. 



Thus far, then, we have seen that there is little 

 difference between the inflammatory process in 

 bone and in any other structure of similar or 

 equal vascular organization ; the chief or cha- 

 racteristic peculiarities must therefore depend 

 on the presence of the earthy material, which 

 we shall find influencing the phenomena of 

 the disease, but perhaps more especially its 

 progress. Thus, whether the operation is sana- 

 tive or otherwise whether adhesion is to be 

 accomplished, ulceration or granulation is to 

 be set up, or a spoiled or dead portion of bone 

 is to be removed the progress of the work is 



more sluggish, and its ultimate accomplishment 

 deferred to a much later period, than in any 

 other animal structure. When a bone is wound- 

 ed, coagulating lymph is thrown out as quickly 

 and with as much facility as from any other 

 tissue, but nothing can be more familiarly 

 known than that it will require a length of time 

 before consolidation is effected, and the solution 

 of continuity is repaired. 



The process of ulcerative absorption in any 

 structure is scarcely understood either as to the 

 stimulus which first determines the vessels to 

 this action or their modus operand! subse- 

 quently; still less can we comprehend how a 

 solid unorganized material like the earthy phos- 

 phate of bone comes to be thus removed. 

 That this process is not performed with the 

 same facility as in softer structures of equal or 

 inferior vascularity is obvious from the tedious- 

 ness of its progress, a delay that is therefore 

 attributable to the presence of this earthy sub- 

 stance. The absorption of the earthy particles 

 takes place under two different conditions; one 

 without the secretion of purulent matter (dry 

 caries), examples of which may be seen in the 

 caries of bones compressed by aneurismal tu- 

 mours, and in some cases of angular curvature 

 of the spine. It is of importance to remark 

 this kind of caries, and to observe that its pro- 

 gress is equally or perhaps more rapid than 

 that in which purulent matter is secreted. 

 Many writers have assumed that pus possessed 

 a solvent quality, and by thus preparing the 

 ossific matter for absorption, materially assisted 

 in. the process an idea which the preceding 

 observation strongly militates against. In the 

 other there is a secretion of purulent matter, 

 and the case is analogous to suppuration and 

 ulceration in the softer tissues, except that the 

 process is still very slow, and in general the 

 odour of the matter is very offensive. 



Adhesion.* Formation of callus. The phe- 

 nomena attendant on this process are most 

 easily and familiarly observed in the re-union 

 of fractures. It is very remarkable, however, 

 that considering the number of celebrated men 

 who have directed their attention to this subject, 

 and the opportunities for observation that are 

 so constantly occurring, nothing has yet been 

 positively determined. We have theories in 

 abundance, apparently founded on and sup- 

 ported by experiment, but still so contradictory 

 that it is impossible not to entertain a suspicion 

 that the theories were in general formed in the 

 first instance, and the facts, if they did not 

 immediately apply, wrested a little in order to 

 support them afterwards. Hence this part of 

 our pathological studies consists of little more 

 than a history of opinions and doctrines neces- 

 sary to be known as constituting part of the 

 literature of the profession, but totally unavail- 

 able to any practical purpose. 



The most ancient explanation of the process 

 by which callus is formed is, that it was per- 

 fected by means of a viscous fluid poured out, 

 around and between the fragments of a divided 

 bone, which were thus mechanically glued to- 



* The adhesive ossific inflammation of Hunler. 



