t>RlNCiPLES OF VETERINARY SWRGERY 609 



HISTOLOGY. — The osseous tissue is found to have al- 

 most disappeared. Instead of 50 per cent of phosphates 

 there is but 2 to 3 per cent. The Haversian canals, which 

 can scarcely be found, are surrounded with fibrous tissue, 

 indicating- not only an inflammation, but also a perversion 

 of nutrition, bearing a close resemblance to a fasciculated 

 sarcoma, and forming wound-up-elements thaf are but 

 slightly vascular. 



LESIONS. — The principal lesions are those of the bones. 

 Every portion of the skeleton is attacked. Their essential 

 character is the rarefaction of the osseous tissue by the dis- 

 appearance of the osseous elements. The alterations are 

 visible to the naked eye, and they vary according to the ex- 

 tent of the disease. They are found to attack the flat bones, 

 the bones of the head, the ribs, the posterior extremities, 

 the pelvis, etc., but to an unequal extent. At the early 

 stages the bones are congested and ecchymosed. The 

 medullary canal is dilated and the marrow is hypersemic. 

 In the more advanced stage these characteristics are ac- 

 centuated. The bones become more fragile and friable, and 

 may fracture without producing a sound. They are easily 

 cut with a knife; diminish in density; and lose 10 to 15 per 

 cent in weight. The periosteum has various aspects. It is 

 slightly chang-ed, bluish or reddish color, and is very vascu- 

 lar, thick, pulpy and easily removed. The articular surfaces 

 are violet colored, ulcerated and exhibit necrosis of the arti- 

 cular cartilagfe. There is arthritis, abundant secretion of 

 synovia and tumefaction of the articulations, of the binding 

 ligaments and of the tendinous attachments. 



The bone, when stripped of its periosteum, presents a 

 porous surface resembling a skimmer or sieve. When 

 squeezed, an oily liquid mixed with blood is pressed out. 

 They are not resistant. The vertebras and the flat bones 

 are particularly rarefied. Numerous fractures are observed 



