In an infected locality the development is always the same. The animals lose flesh, become anæmic, and, unless vigorously treated, soon die. The ordinary duration of the disease is from five to eight months, sometimes more. If, however, patients are isolated and well treated they recover. =Causation.= The specific cause of foot rot still remains to be discovered, although everything points to the conclusion that it consists in an organism capable of cultivation in manure, litter, etc., for foot rot is transmissible by cohabitation, by mediate contagion through infected pasture, by direct contact and by inoculation. The chief favouring influences are bad drainage, filthy condition of the folds, and herding in marshy localities. =Diagnosis.= The condition can scarcely be mistaken, for the sheep suffers from no other disease resembling it, excepting, perhaps, foot-and-mouth disease. =Prognosis.= The prognosis is grave, for the disease usually assumes a chronic course, affects entire flocks, and the patients require individual attention. =Treatment.= The primary essential to success in treatment consists in separating and isolating the diseased animals in a scrupulously clean place and providing a very dry bed. In the early stages the disease may be checked by astringent and antiseptic foot baths. It is then sufficient to construct a foot-bath at the entrance to the fold, containing either milk of lime, 4 per cent. sulphate of iron, copper sulphate, creolin, etc. Through this the sheep are passed two or three times a week. These precautions rarely suffice when the feet are already extensively diseased; and when the horn is separated to any considerable extent, surgical treatment is indispensable. All loose portions of horn should be removed and antiseptic applications made to the parts. When a large number of sheep are affected the treatment is very prolonged, but it is absolutely indispensable, and the numerous dressings required necessarily complicate the treatment. It would be valuable to experiment with small leggings, which would retain the dressings in position, and, at the same time, shelter the claws from the action of the litter, while favouring the prolonged action of the antiseptic. When the lesions are not extensive, a daily dressing is sufficient. Among the materials most strongly recommended are antiseptic and astringent ointments containing carbolic acid, iodoform, or camphor. Vaseline with 5 per cent. of iodine is very serviceable, and much to be preferred to applications like copper sulphate, iron sulphate, etc. Its greatest drawback is its expense. CHAPTER III. DISEASES OF THE SYNOVIAL MEMBRANES AND OF THE ARTICULATIONS. I.—SYNOVIAL MEMBRANES AND ARTICULATIONS. SYNOVITIS.