animal, which subsists upon it as an exclusive diet, even though the actual pathogenic microbe may not be present in the secretion. With regard to fermented milk, that which has been simply soured, relaxes the bowels and the attendant congestion contributes to further derangement and even infection by any pathogenic germ which may be present, or by microbes which are habitually saprophytic, but take occasion to dangerously attack the weakened mucosa. If the milk has undergone putrefaction in the feeding bucket, the co-existence of the septic germ and the septic ptomaines and toxins, often determines indigestion and irritation of the mucosa. These poisons may further be absorbed and produce general constitutional disorder which reacts most injuriously on the stomach and digestion. Milk swallowed rapidly and in excess by a hungry calf or foal, overdistends the stomach, which, like other hollow viscera in such conditions, is rendered paretic or paralytic, and suffers from suspension of both the vermicular contractions and the peptic secretions. Under these conditions the milk, which is one of the most admirable culture media for bacterial ferments, undergoes rapid decomposition, with the production of a series of toxins and ptomaines varying according to the different kinds of microbes that may be present. Under such conditions microbes which are normally harmless, vigorously and destructively attack the mucous membrane and determine some of the worst types of juvenile diarrhœa. In artificial feeding there is another serious danger. Calves in particular are brought up largely on gruels made from farinaceous material. These contain a large quantity of starch which requires the action of the saliva (ptyaline) to resolve it into glucose, and fit it for absorption. But in the early days of life the salivary glands are almost entirely inactive, and it is only as the first three stomachs develop that this secretion becomes normally abundant. This is sought to be met by fixing in the feeding bucket a rubber teat, which the young animal is made to suck so as to solicit the secretion of saliva. The benefit obtained is however more from the slower ingestion of the milk than from any material increase of saliva from the as yet functionally inactive glands. The presence of hair balls in the stomach, derived from the skin of themselves or others is one of the most injurious of the causes of juvenile indigestion. Lying as these do at this early age in the one well developed stomach they interfere with its normal secretions, and being at first open in texture they become saturated with putrefying ingesta, which gives out the most poisonous products. The milk is materially affected by the food eaten by the nursing animal and such variations in the milk tend at times to derange a weak stomach. The following table from Becquerel and Vernois gives the results of dry and succulent food on the amount of the different proximate principles in the milk.