“In more acute cases (from sudden access of green food, change of water, or ingestion of irritant plants), the affection partakes more or less of the nature of congestion or inflammation of the viscus (omasitis), and may run a rapidly fatal course” (Law, _loc. cit._). The animal is seen apart from the herd in a characteristic recumbent position, the eyes are red and glassy, the eyelids semi-closed, the patient shows much drowsiness and stupor, but when raised may still feed in a sleepy, listless manner. The bowels are loose or confined, the pulse and breathing accelerated, the right hypochondrium is firm and tender, and the sound of fermentation absent or subdued over the omasum. Soon nervous disorder appears, the eyes glare wildly, the animal seeks relief in motion—sometimes in a straight line, sometimes to one side—and being blind and unconscious of obstacles, may fall into pits or ditches, knock against trees, fences, gates, or buildings, and continue pushing against resisting objects, breaking its horns or teeth; and otherwise sustaining injury through violent muscular contractions. =Course.= Chronic cases may continue indefinitely, with symptoms of poor health, impaired digestion, and gradual loss of condition. After death the omasum may contain dried food which the animal consumed several months before the attack. In cases ending in early recovery there occurs abundant diarrhœa, “the fæces are mixed with flattened, dark, solid, and polished masses, the impacted ingesta from the omasum. Tympany subsides; movement in rumen and omasum and rumbling in bowels can be heard. Appetite returns.” (Law.) =Diagnosis.= The condition of the pulse and respiration, and the grunting with expiration may lead to confusion with pneumonia. At first there is no fever, tenderness is confined to the right flank; there is an absence of pulmonary crepitation, of pleural effusion, and of movement in the rumen and omasum. Signs of gastric and intestinal disorder can be detected. =Lesions.= The omasum is gorged—it may be twice its normal size—solid, resistant, almost stony. The spaces between the leaves are packed with dried food, which, when removed, carries a layer of epithelium from the mucous membrane. (This (layer on contents) is not inconsistent with health.) The rumen contains ingesta packed in masses, more or less offensive from putrefaction. The abomasum is empty of food, but contains much mucus. Its mucous membrane is congested. The small intestine is red in places, empty and collapsed. The larger intestine contains a quantity of dry, glistening pellets, and much mucus. =Treatment= follows the lines of impaction of rumen, though the response is usually less certain, and always slower. Flax-seed tea, several bucketfuls per day, will often succeed. Epsom and common salts, with sol. ammoniæ, excite thirst; liquids should be supplied freely.