DISEASES OP THE BONES. 285 



fected, and to determine positively whether the periosteum or the 

 body of the bone is originally implicated. Yet a knowledge of the 

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

 result 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 involv- 

 ing the articulation itself, certain bony growths, or exostoses, known 

 otherwise by the term splint, ringbone, and spavin, all of which, in an 

 important sense, may be finally referred to the periosteum as their 

 nutrient source and support, at least after their formation, if not for 

 their incipient existence. 



Cause. — 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, more 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. 



Symptoms. — This condition of periostitis is often difficult to deter- 

 mine. The signs of inflammation are so obscure, 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 locate 

 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 fact 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 senses. 



Treatment. — When, by careful scrutiny, the ailment has been 

 located, a resort to treatment must be had at once, in order to pre- 

 vent, if possible, any further deposit of the calcareous structure and 

 increase of the exostotic growth. With this view the application of 

 water, either warm or cold, rendered astringent by the addition of 

 alum or sugar of lead, will be beneficial. The tendency to the forma- 

 tion of the bony growth, and the increase of its development after 

 its actual formation, may often be checked by the application of a 

 severe blister of Spanish fly. The failure of these means and the 

 establishment of the diseased process in the form of chronic perios- 

 titis cause various changes in the bone covered by the disordered 

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