Mr. Farnum's Lecture.

"To-night we shall discuss digestion and in turn take up the various factors in this very important process." Saliva, the first factor, has a mechanical action, by penetrating all through the food in the mouth, it makes the work of grinding it up by the teeth much more easy. It is an alkaline fluid, and has the property of changing starch into sugar. Mr. Huxley's model man would eat 12 oz. of bread and 6 oz. of potatoes every twenty-four hours.

Starch is a compound of carbon, hydrogen and oxygen, each of them an essential constituent of the body. All food should be well masticated, and the proportion of vegetable and animal foods eaten carefully considered. When a portion of food, or drink, saliva, or any other substance has been carried back past a certain point on the posterior part of the tongue, it is completely out of our power to resist swallowing. After leaving the mouth the food passes through the oesophagus to the stomach, which is a hollow muscular organ, and provided with a number of glands which produce the gastric juice. The muscles of the stomach are described as consisting of three layers. At the lower opening is a muscle called the sphincter, which opens and shuts the outlet into the intestines. The mucous membrane lining the stomach is continuous with that in the mouth, running along down through the oesophagus. When the stomach is empty it is thrown into folds, which become smooth as it fills up. Alexis St. Martin, who was the means of furnishing most of our knowledge of the functions of the stomach, was under observation for thirty-two years. On stimulation of the stomach by any means the gastric fluids begin to flow. It is said that drinking large quantities of water impedes digestion by diluting this gastric juice. Violent muscular exertion before or after eating has the same effect. Live tissue can be digested, and after death the stomach sometimes digests itself. The pancreatic juice and the bile are poured into the small intestine. The amount of bile secreated in twenty-four hours has been estimated at forty ounces.