LAMENESS: ITS (.'Al'SES AND TREATMENT. 309 



mals the onset and progress of mysterious iuul iinreeon^iizable ail- 

 ments will at times halHe the most skilled veterinarian, and leave our 

 burden-bearino: servants to siicrnmb to the inevitable, and siiU'er and 

 perish in unrelieved distress. 



DISEASES OF BONES. 



PERIOSTITIS, OSTITIS, AND EXOSTOSIS. 



From the closeness and intimaev of the connection existing; between 

 the two jirinoipal elements of the bony sti'uctnre while in health, it 

 fre(iiiently becomes exceedingly dillicnlt, when a state of disease has 

 supervened, to discriminate accurately- as to the part primarly af- 

 fected and to determine positively whether the periosteum or the 

 b< dy of the bone is originally implicated. Yet a knowledge of the 

 fact is often of the first importance, in order to obtain a favorable 

 I'esult from the treatment to be instituted. It is. however, quite evi- 

 dent that in a majority of instances the bony growths which so fre- 

 quently appear on the surface of their structure, to which the general 

 term of exostosis is applied, have had their origin in an inflammation 

 of the periosteum, or enveloping membrane, and known as periostitis. 

 However this may be, we have as a frequent result, sometimes on the 

 body of the bone, sometimes at the extremities, and sometimes in- 

 volving the articulation itself, certain bony growths, or exostoses, 

 known otherwise by the term of splint, ringbone, and spavin, all of 

 which, in an imjwrtant sense, may be finally referred to the perios- 

 teum as their nutrient source and support, at least after their forma- 

 tion, if not for their incipient existence. 



Cmise. — It is certain that inflammation of the periosteum is fre- 

 quently referable to wounds and bruises caused by external agencies, 

 and it is also true that it may possibly result from the spreading 

 inflammation of surrounding diseased tissues, but in any case the 

 result is uniformly .seen in the deposit of a bony growth, moi-e or less 

 diffuse, sometimes of irregular outline, and at others projecting dis- 

 tinctly from the surface from which it springs, as so commonly pre- 

 sented in the ringbone and the spavin. 



SyviptorriA. — This condition of periostitis is often diflicult to «leter- 

 mine. The signs of inflammation are so ob.scure, the swelling of the 

 parts so insignificant, any increase of heat so imperceptible, and the 

 soreness so slight, that even the most acute observer may fail to find 

 the point of its existence, and it is often long after the discovery of 

 the disease itself that its location is positively revealed by the visible 

 presence of the exostosis. Yet the first question had been resolved, 

 in discovering the fart of the lameness, while the second and third 

 remained unanswered, and the identification of the affected limb 

 and the point of origin of the trouble remained unknown until their 

 palpable revelation to the sense.s. 



