724 DISEASES AND ABNORMALITIES OF THE YOUNG ANIMAL. 



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

 over the most prominent portions of the joint becomes absorbed, 

 ulcerates, and if not divided by 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 fcetor 

 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 — i.e., when the lymph is plastic and 

 the constitution strong — it undergoes healthy organisation, and remains 

 as a part of the joint, producing, however, permanent thickening, dis- 

 tortion, and stif&iess. 



Prognosis, 



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

 regard to this disease must always be unfavourable, 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 

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



Pathological Anatomy. 



According to Eoloff, the predominant lesions are the characteristic 

 alterations of rachitism and periostitis. The cartilage uniting the 

 epiphyses to the shaft of the bones is soft from cellular proliferation, and 

 injected 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 they are of a much 

 more serious character than those observed in adult animals. The 

 synovial membrane is highly inflamed, and there is great infiltration of 

 the connective tissue around the joints. 



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

 yellow-coloured 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 remarked that, in Lambs, the 2wst mortem appearances are 

 general and local. The general, in the earlier stages, are effusion of 

 lymph between the intercostal muscles, beneath the pleura and into the 

 lungs, and in other organs ; with hyperemia or engorgement of the 

 small bloodvessels of the mucous membrane of the stomach (fourth 

 compartment) and intestines. 



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

 tions are found under and within the structure of the skin of dependent 

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

 various cavities of the body. The large bloodvessels — even those of the 

 brain — are filled with dark, grumous, damson-coloured blood ; the 

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

 full of minute abscesses, which give it a mottled appearance that is fre- 

 quently mistaken for tuberculosis ; all the organs and tissues are tinged 

 with the colouring matter of the bile ; the small vessels of the omentum 

 are charged with blood, and the mucous lining of the fourth division of 

 the stomach is congested and black wherever the milk has lain in con- 



