_Causes._ It commences in _paresis of the rumen_ in the weak, debilitated, convalescent or starved animals which are suddenly put on rich, and appetizing food. Hence it is common in animals that break into a cornbin, a store of potatoes, a field of growing corn or small grain, or that are turned out on green food in early spring. Cadeac maintains that paresis of the rumen is the essential cause in all cases, while the nature of the aliments ingested fills a secondary and comparatively insignificant rôle. According to this view the torpid stomach can neither relieve itself through regurgitation for rumination, nor expel through the œsophagus the constantly evolving gas which therefore distends the viscus to excess. In support of this view may be adduced the occurrence of tympany through fatigue, fear, cold, enlarged (tubercular) mediastinal glands pressing on the gullet and vagus, obstruction of the œsophagus by a solid body (choking), impaction of a morsel of solid food in the demicanal of the calf as noticed by Schauber, and the cessation of the normal vermicular movements of the rumen in connection with inflammation of its coats, or extensive inflammation elsewhere or finally of fever. Even in paralysis of the stomach by poisons like lead, tympany may be a result. Cadeac attributes tympany following the ingestion of green food wet with a shower, or drenched with dew, of frosted potatoes or turnips, or of iced water, to the paralyzing action of the cold on the rumen. This view is manifestly too extreme, as the bloating occurs often after a warm summer shower, or after the consumption of potatoes and other roots and tubers which have been spoiled by frost but which are no longer at a low temperature when consumed. _Tympany_ may also start from the ingestion of certain kinds of _food_ which are _in a very fermentescible condition_. Green food, especially if the animal has been unaccustomed to it, is liable to act in this way. Clover and especially the white and red varieties, lucern (alfalfa), sainfoin, cowpea and other specially leafy plants, which harbor an unusual number of microbian ferments, and which contain in their substance a large amount of nitrogenous material favorable to the nourishment of such ferments are particularly dangerous in this respect. All of these are most dangerous when wet with dew or when drying after a slight shower, partly no doubt at times by reason of the chilling of the stomach, but mainly because the ferments have been stimulated into activity by the presence of abundance of moisture. Drenching and long continued rains are less dangerous in this respect than the slight showers and heavy dews, manifestly because the former wash off a large portion of the microbes, which under a slight wetting multiply more abundantly.