Local chills, produced by ingestion of food covered with rime, hoarfrost, or simply with dew, may favour gaseous indigestion; such conditions retard or suspend the peristaltic movements by direct local action, and probably by producing vaso-motor disturbance of the mucous membrane. In very rare cases chill has an undeniable influence, either by provoking general vaso-motor disturbance, which reacts on the secretions, or neuro-motor trouble. Gaseous indigestion is not uncommon in animals living on dry winter food, which have been moved from their ordinary quarters and sent on railway journeys or to fairs, etc. As a general rule this form of indigestion is commonest in spring, when the transition from dry winter food to grass, etc., has not been carefully effected. It is also frequent during stormy weather in full summer. Marked barometric changes seem to have an influence on the general health, and particularly on the nervous system, thus favouring organic fermentations. =Symptoms.= The earlier symptoms of indigestion escape observation, but they soon begin to develop rapidly, and are then very easy to follow. They always exhibit the same characters, developing, however, with more or less rapidity in different cases. Soon after they commence feeding animals appear to experience special discomfort, which causes those at grass to stop grazing; even when stabled they stop feeding. From this time they show eructation, repeated yawning, restlessness, and some anxiety. In a quarter of an hour, or less, the left flank begins to project, both laterally and vertically, so that eventually the walls of that part of the abdomen may project above the transverse processes of the lumbar vertebræ. The right flank also becomes swollen, as a consequence of the intestine being thrust out of position. The animal very rapidly shows general disturbance; the nostrils are dilated, the mucous membranes congested, respiration becomes rapid, and asphyxia threatens. The respiration soon becomes panting, for the distended rumen paralyses the diaphragm and compresses the lungs. To ease respiration the animals open the mouth, extend the neck, and stand with the front limbs spread apart; but this fails to prevent dyspnœa becoming more intense and asphyxia imminent. The heart beats more rapidly, the superficial veins appear swollen, and the mucous membranes cyanotic. The rhythmic contractions of the rumen can no longer be detected by manual examination of the left flank; and on auscultation one neither hears the liquid nor the rolling sound, but only exaggerated crepitation. Finally, there is marked tympanitic resonance on percussion. In cases of very grave tympanites the gaseous pressure in the interior of the rumen appears to stop the crepitation sound. The animals soon become unable to walk or even to move, suddenly fall to the ground, and die rapidly from asphyxia.