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Show £12 I would have my reader to recollect the phenomena of the formation of bone, in cartilage, in membranes, or in that mass, which we are accustomed to call callus, around the ends of a broken bone ; of the formation of new membranes; of the adhesion of the soft parts by an intermediate sub stance; as well as of the formation of tumours from coagulum, as it is imagined. And I intreat him not to attach himself entirely to a solitary fact, nor to give himself up implicitly to the guidance even of a Hunter, who, amidst all the splena dor of his talents, was often unintelligible. 1. I think the leading error of this doctrine is the inat~ tentiou to the distinction between the coagulum thrown out from the organized extremities, and that which is spilt as it were by the accidental rupture of a vessel. In the one instance it is a secretion; and in the other a mere extravasa- «as- an or removes. or rumouns. tion, possessed of no power of reproduction; absorbed, if in a small quantity ; a source of inflammation and suppuration, if in a great quantity. I must see the coagulum of blood thrown out in apoplexy, and in aneurism, full of vessels, before yield- ing up the conviction that the coagulum of blood accidental~ 1y thrown out is absorbed, and a new deposition secreted. previous to the formation of vessels. 2. It is matter of surprizc to me, 110w the physiologists, who support the original observation of Mr. Hunter, can adhere with such devotion to the circumstance of this coagulum forming a connexion with the peritoneum obscurely imagined ; when if the fact were so, viz. that coagulum of pure blood formed adhesion to that, or any other surface, and grew there, it would be as familiarly known to every surgeon, 215 the pure coagulum of blood escaped from the rupture of an artery, or a vein, has no power of adhesion, or of forming vessels within it, yet if circumstances should present themselves to convince me of my error, the following View of the subject would stand uncontrovertcd by that circumstance. 41. Every part having a peculiarity of structure, preserves that peculiarity by the prescribed modification in the activity of its vessels ; this modification is continued when the part is injured, or cut, and the renovated matter is consequently like the original substance. Violent injury will sometimes interrupt this natural renovation; but on the subsiding of the violent commotion, and the return of the natural action, the part is reinstated. As, however, the functions, (and we may perhaps venture to say the structure,) of some parts of the body are more delicate and peculiar, these are not restored in all their pristine perfection, though always with such a relation to it as to show that the bond of union of the divided parts is not the same in all, but holds a relation to the origin- al formation. 5. If a bone is broken, a coagulum is thrown out ; the ves- sels of the bone penetrate this eoagulum, and the vessels of bone deposit bone. Such is the received explanation of the formation of new matter of bone, and a most imperfect one it is. This opinion does not at all correspond with the facts, which stand thus: The mass which we call callus, and which surrounds the broken ends of bones, is supplied with vessels principally from the surrounding soft parts, and yet bone is formed. If, therefore, the source from which the vessels chance to be derived influenced their action, muscle and as it is demonstrable that extravasated blood is absorbed, and that a limb turgid with extravasated blood will resume its membrane would be formed, instead of earthy matter depo- form. 3. We frequently have coagulum thrown out from inflanr ed surfaces with such a proportion of the colouring particles of the blood, as to appear like a pure coagulum of blood some- what blanched; and I have no doubt the coagulum found by Mr. Hunter was of this nature. But While I believe that original coagulum of blood, which is by the violence of the. accident, and the rupture of vessels, thrown out around the extremities of the bone, is absorbed, and a new deposition is slowly secreted ; the source of that secretion is the bone, and bone is formed in that nidus, although the vessels supplying it with blood be from parts entirely different in structure and The fact, as it has appeared to my eyes, is, that the . r.~1'~"'\j‘ oWWo-w, "an . _ sited. '7‘ . WON! 3,. vi ' M099» |