My lord the stomach! He is not the only, nor is he the chief, agent in digestion; but with him rests the decision as to whether the food offered to the alimentary tract is suitable in quality and quantity. He is offended if it be not offered with all the circumstance and ceremony which becomes his rank. As an intimation that he is about to receive food, he accepts the news from the mouth that its nerve-endings are subject to mechanical stimulation. But the chewing of indiarubber would produce a like effect. The stomach, therefore, confers with the organs of taste and smell. If their report is favourable, he argues that the substance which the teeth are crushing will justify an outflow of gastric juice. He responds most generously when prolonged mastication assures him that he may trust to receiving the food in a sufficiently subdivided state. At our peril we neglect to propitiate my lord. Not always debonair when treated with consideration, he is morose or petulant when slighted. Never content with lip-service, he exacts the labour of teeth and tongue and palate. The tribute we offer may be of the best—savoury, wholesome, well cooked, well chewed—but if it be not tendered with some degree of love, if thoughts are concentrated on other things, if no attention is devoted to the meal, if no sense of liking accompanies our offering, my lord the stomach on his part affords the viands an indifferent reception. In consulting our own tastes we are to a large extent consulting the needs of the stomach. Ravenous and excessive feeding is not an exhibition of taste; it is a return to the instinct of the savage, who was never sure that he would get his full share, and was afraid to trust that another meal would be obtainable when nature declared it due. Some degree of epicureanism is favourable to digestion. The flow of gastric juice in the stomach occurs reflexly in response to the emotion of appetite, to stimulation of the nerves of taste and smell, to the obscure sensations which accompany the activity of the muscles of mastication. The gastric juice secreted in a day amounts probably to about 8 or 9 pints. To this we must add, when considering the quantity of fluid which passes through the stomach, the saliva, which certainly reaches as much as 2 pints, and the beverages taken with food. Gastric juice collected in the manner described above is a clear, colourless, inodorous fluid. It is very acid, and so powerfully peptic as to digest its own weight of coagulated white of egg. Its solid constituents amount to 0·5 per cent. They consist of the two ferments pepsin and rennin, with traces of proteins and mucin, and various inorganic salts. Its acidity is due to free hydrochloric acid to the amount of 0·2 per cent. This acid is more or less in combination with the pepsin. In pure gastric juice hydrochloric acid is the only acid present; but when mixed with food the juice contains other acids also, especially lactic.