280 THE MODERN HORSE DOCTOR- 



consist in any acts or efforts of speed or strength productive of 

 concussion to the bones of the pastern. Some have ascribed the 

 presence of ringbone to blows. Undoubtedly, a blow upon a bone 

 would be very likely to produce exostosis ; but the pastern, the 

 hind pastern in particular, is rather an unlikely part to be struck. 

 After inflammation from any cause, even after that produced by 

 a common blister, very often we know an enlargement of the 

 pastern will be left ; and though this is not called ringbone, it 

 may be regarded as something very analogous to it." 



Nature of Ringbone. — " Ringbone is but a species of exos- 

 tosis — a bony tumor, which in one situation constitutes ring- 

 bone, in another splent, in another spavin ; yet the three differ 

 as well in their origin as in their effects. Ringbone has an ex- 

 ternal origin ; and though it may, from spreading, interfere with 

 the motion of a joint, still it does not, that we know of, produce 

 any affection of the synovial membrane ; spavin, on the con- 

 trary, seldom confines itself to the external or ligamentary tis- 

 sues, but affects the synovial membrane as well ; and splent 

 originates in the very joint — the Jibro-cartilaginous — which it 

 afterwards blocks up and grows from. 



" Ringbone is either a ligamentary or a periosteal affection, or 

 both. From the situation in which, we commonly find it, and 

 from the causes which are known to give rise to it, we believe it 

 usually to be ligamentary in its beginning ; though, when once 

 formed and given to spread, no tissue, save the tendons, escapes 

 conversion, to contribute to the osseous mass ; and even the ten- 

 dons themselves have been known to become partly ossified. In 

 fact, when the exciting cause has been great, or when there 

 exists an evident proneness in the constitution to ossific action, 

 such is the extensive and varied form ossification takes on, that 

 we can hardly say when it will end, so long as any soft tissues 

 yet remain to be converted. "Writing in the year 1823 on this 

 subject, with a hundred and fifty morbid specimens of the kind 

 upon the table before us, we find we were led at the time to make 

 the following remarks : — 



" ' By far the most common seats of [ossific] disease are the 

 pastern, coronet, and coffin bones. Out of the said hundred and 

 fifty specimens there are 



