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Referring to that series of bones, which seems to approximate the 

 nearest to the entrochi, I mean the vertebrae, to the diseases of which, 

 in the human body, particular attention has been paid, two most 

 prominent facts are observable. The one is, that in every disease of 

 these parts in which the substance of the bone has been so materi- 

 ally affected, as to have been rendered unfit for motion, the articu- 

 lating surfaces anchylose together, so that the morbidly tender parts 

 are no longer liable to injury by motion. The other fact is, that as 

 these parts, weakened by disease, must, of course, be less capable of 

 supporting the weight naturally imposed on them, an exudation of 

 lymph is thrown out, in which is deposited that portion of earthy 

 matter which is necessary to the constitution of callus. By this pro- 

 cess, the consequence of injury and of inflammation of these parts, 

 the requisite degree of support is obtained, although the motion im- 

 mediately belonging to these parts is lost. 



The specimen to which I have called your attention bears indubi- 

 table marks of these entrochi having been the subjects of both these 

 processes. The naked eye at once sees, in that part of the straight co- 

 lumn which is uncovered, an unnatural state of the trochitae or verte- 

 brae : their forms are not similar, nor are their lines of articulation re- 

 gular. By a closer inspection, especially with a magnifying glass, it 

 may also be discovered, that the processes forming the crenulated 

 edge have been removed, and that a line only slightly undulated, 

 marks where the articulation existed, and shews plainly such a species 

 of connection between the trochitae as must have occasioned a com- 

 plete anchylosis. 



Equally positive is the evidence in favour of the substance, in 

 which these entrochitae are involved, being produced by the powers of 

 restoration possessed by the animal. Its colour, its texture, and, in- 

 deed, its general appearance, accord so exactly with those of the en- 

 trochi themselves, as to render it indubitable that it has proceeded 

 from a similar organization. 



