Cows fed on overkept, fermented, and soured rations have acid milk, which readily turns and coagulates. Thus old, long-kept brewer's grains, swill, the refuse of glucose factories, and ensilage which has been put up too green all act in this way. The same may come from disease in the cow's udder, or any general disease of the cow with attendant fever, and in all such cases the tendency is to rapid change and unwholesomeness. If the milk is drawn and fed from a pail, there is the added danger of all sorts of poisonous ferments getting into it and multiplying; it may be from the imperfect cleansing and scalding of the pail; from rinsing the pails with water that is impure; from the entrance of bacterial ferments floating in the filthy atmosphere of the stable, or from the entrance of the volatile chemical products of fermentation. In addition to the dangers coming through the milk, the calf suffers in its digestive powers from any temporary illness, and among others from the excitement attendant on the cutting of teeth, and impaired digestion means fermentations in the undigested masses and the excessive production of poisonous ptomaines and toxins. Whatever may be the starting or predisposing cause of this malady, when once established it is liable to perpetuate itself by contagion and to prove a veritable plague in a herd or a district. _Symptoms._--The symptoms of a diarrhea may appear so promptly after birth as to lead to the idea that the cause already existed in the body of the calf, and it usually shows itself before the end of the second week. It may be preceded by constipation, as in retained meconium, or by fetid eructations and colicky pains, as in acute indigestion. The tail is stained by the liquid dejections, which are at first simply soft and mixed with mucus with a sour odor, accompanied with a peculiar and characteristic fetor (suggesting rotten cheese), which continually grows worse. The quantity of water and mucus steadily increases, the normal predominance of fatty matters becoming modified by the presence of considerable undigested casein, which is not present in the normal feces, and in acute cases death may result in one or two days from the combined drain on the system and the poisoning by the absorbed products of the decomposition in the stomach and bowels. When the case is prolonged the passages, at first 5 or 6 a day, increase to 15 or 20, and pass with more and more straining, so that they are projected from the animal in a liquid stream. The color of the feces, at first yellow, becomes a lighter grayish yellow or a dirty white (hence the name white scour), and the fetor becomes intolerable.