When the chyme passes into the duodenum it finds preparation made for it. The pancreas commences to secrete as soon as food enters the stomach; hence a quantity of its secretion is already accumulated in the intestine when the chyme enters. The gall-bladder is distended with bile, secreted since the last meal; the acid chyme stimulating the duodenal mucous membrane causes, through the nervous system, a contraction of the muscular coat of the gall-bladder, and so a gush of bile is poured out on the chyme. From this time on both liver and pancreas continue secreting actively for some hours, and pour their products into the intestine. The glands of Brunner and the crypts of Lieberkühn are also set at work. All of these secretions are alkaline, and they suffice very soon to more than neutralize the acidity of the gastric juice, and so to convert the acid chyme into alkaline chyle, which, as found in the intestine after an ordinary meal, contains a great variety of things: water, partly swallowed and partly derived from the salivary and other secretions; some undigested albumens; some unchanged starch; oils from the fats eaten; peptones formed in the stomach but not yet absorbed; salines and sugar, which have also escaped complete absorption in the stomach; indigestible substances taken with the food; all mixed with the secretions of the alimentary canal.

What is chyme? What things would be found in chyme after an ordinary meal? When does chyme begin to be sent on to the intestine? How? How soon is the stomach completely emptied after a meal? What has accumulated in the small intestine when the chyme reaches it ?

* Several of the above facts were first observed on a Canadian trapper. Alexis St. Martin, who as a result of a gunshot wound had a permanent opening from the surface of the abdomen to the interior of the stomach.