_Symptoms: Chronic Form._ In Argentina, Lignieres observed the disease especially during the hot summer months (December to May), and after weaning in the lambs. This may be from the marked change of food, from the greater activity of microbian life at this season, from the exhausting effect of the heat, or from a combination of two or more of these conditions. It appears alike in the sheepfold, and on the open prairie. In considerable flocks the symptoms may be at first overlooked, so that the death of several sheep may be the first thing to draw attention. Then a certain number are found to scour, arch the back, walk stiffly, lose condition, and have the wool flattened and devoid of yolk (_clapped_ wool). The sheep may be dull, lagging behind its fellows, or lying apart by itself, ruminating infrequently and for shorter periods than natural, and there may be inappetence, or depraved appetite (eating earth), though some eat well to the end. Irregular and at intervals capricious appetite is a frequent condition. When caught and examined, the wool is easily torn out, the muscles are soft and wasted, (the leg muscles may have practically disappeared), the bones stand out at all points, the skin is pale, thin, bloodless and devoid of its subcutaneous fat, (paper skin), there may be œdemas along the ventral aspect of the body, pitting on pressure, and between the branches of the lower jaw (poked), the eyes are sunken, the conjunctiva may be puffy and œdematous, but like the muzzle and mouth they are pale and anæmic and the pulse is small, though the excitement may have roused cardiac palpitations. The temperature varies from time to time often reaching 105° or 106° F. There is liable to be a muco-purulent discharge from nose and mouth especially noticeable during drinking. As the disease advances the subject becomes weak, paretic, dull and stupid, it remains down without interest enough to seek food, though still eating if it is brought to it. The head is usually rested on the flank, and the animal often lies so for days in a state of semi-stupor without disposition or ability to rise, paretic or paraplegic. Auscultation may sometimes detect a mucous râle or crepitus, and percussion a flatness of sound over some part of the lung. Chronic arthritis is an occasional symptom. _Diagnosis._ The symptoms closely resemble those of distomatosis or strongylosis, and the disease is often complicated with one or more of these, so that it may become difficult to judge how much is due to the microbian infection and how much to the helminthiasis. The presence, continuously or intermittently, of the hyperthermia is almost pathognomonic of the operation of the microbe.