742 DISEASES AND ABNORMALITIES. 



from bulging of the more flaccid portions of the synovial membrane and 

 skin ; and, from portions of the effused lymph becoming liquefied, fluc- 

 tuation is produced — other portions remaining solid. The fluctuating 

 swellings extend along the thecse or sheaths of the tendons — two joints 

 often becoming in this way connected with each other ; finally, the skin 

 over the most prominent portions of the joint becomes absorbed, ulcer- 

 ates, and if not divided with the lancet or by accidental violence, bursts 

 — allowing the escape of the contained fluids and semi-solid matters, 

 and being followed by sinuous ulcers, caries, or abscess proper, of the 

 joint. The sinuses may extend a considerable distance from the joint, 

 and discharge an ichorous unhealthy fluid, accompanied by foetor if bony 

 or ligamentous structure is involved. In some cases the exuded lymph 

 simply becomes liquefied and absorbed, without any external opening 

 being formed ; in others — /. e., when the lymph is plastic and the consti- 

 tution strong — it undergoes healthy organization, and remains as a part 

 of the joint, producing, however permanent thickening, distortion, and 

 stiffness.. 



Prognosis. 



From what has been stated, it will be seen that the prognosis with re- 

 gard to this disease must always be unfavorable, especially when the 

 creature is very young. The mortality reaches as high as forty, fifty, 

 sixty, and even more per cent. Indeed, Darreau states that eighteen out 

 of every twenty foals die ; and Lecoq says that the breeders in Noi*mandy 

 have an axiom, " Poulain boiteux, poulain perdu." 



Pathological A?iatomy, 



According to Roloff, the predominant lesions are the characteristic 

 alterations of rachitism and periostitis. The cartilage uniting the epiphy- 

 ses to the body of the bones, is soft from cellular proliferation, and in- 

 jected in places by hsemorrhagic spots ; the periosteum is also thickened, 

 injected, and here and there detached from the bones ; while towards the 

 diarthrodial surfaces the bone tissue is greatly involved. There are, in 

 fact, all the lesions of arthritis, but of a much more serious character than 

 are observed in adult animals. The synovial membrane is highly in- 

 flamed, and there is great infiltration of the connective tissue around the 

 joints. 



Reynal has found in the intra-articular cavities of the joints, deep- 

 yellow-colored clots, streaked with red, and elastic and firm, which are 

 nothing more than false membranes that have had time to form in the 

 short space of two to five days. 



Walley remarks that, in lambs, the post-7nortem appearances zxt general 

 and loca,l. The general, in the earlier stages, are effusion of lymph be- 

 tween the intercostal muscles, and beneath the pleura and into the lungs 

 and other organs ; with hyperaemia or cngorge'ment of the small blood- 

 vessels of the mucous membrane of the stomach (fourth compartment) 

 and intestines. 



If the disease has existed for any length of time, erysipelatous exuda- 

 tions will be found under and within the structure of the skin of depend- 

 ent parts, or effusion of serum (dropsy) into the connective tissue, and 

 into the various cavities of the body. The large blood-vessels — even those 

 of the brain — are filled with dark grumous damson-colored blood ; the 

 structure of the brain is dark : the liver is often enlarged, friable, and 



