Dilation of the stomach may arise either from physical or physiological causes. In the former case it results from the slow growth of malignant and other formations in or around the pyloric opening by which the food is prevented from escaping into the small intestines. In the latter - the more common form of the affection - it appears more especially in old animals who have led a life of indolence and high living, and are then cast away to subsist on large quantities of coarse indigestible food. Under these circumstances the mucous membrane becomes atrophied, pale in colour, and more or less disorganized, while the muscular coat is thin and greatly stretched, so that the organ is two or more times larger than it should be. Chronic dilation of the stomach and of the intestines also is sometimes seen in old broken-winded animals.
These partake of the character of indigestion, with more or less rapid wasting. At first the appetite falls away, the skin becomes staring and dirty, the belly increases in size, the bowels are irregular - at one time constipated, at another relaxed, always distended with flatus.
In this disease treatment is of little avail. In the majority of cases it is an evidence of general decay, and where it arises from causes which obstruct the passage into the bowels, as from tumours in and about the pylorus, there is little to be hoped for.