The second reagent which is poured out on the raw material in the digestive canal is the gastric juice. How, in the normal course of events, is the work of the gastric glands, which prepare this juice, called into play? With the first, and manifestly important factor, which has a relation thereto, you are already acquainted, and, indeed, have already seen. I refer to the production of gastric juice in the empty stomach, as a result merely of the swallowing of food in the so-called sham feeding of an œsophagotomised dog. When one takes into consideration the absolute independence of this factor, and the intensity of the effect, which makes itself evident in the secretion of a large quantity of juice of high digestive power, the exciting agency which brings about such secretion must be recognised as one of the most important and effective processes in gastric digestion. But in what does it consist? At first sight it appears--and when I previously drew your attention to the fact I expressed the opinion--that there is here a simple reflex effect from the cavity of the mouth upon the secretory nerves of the stomach, similar to the reflex excitation, _e.g._, of the parotid gland, by finely powdered flesh thrown into the mouth. Now, however, I assert quite emphatically that this is not the case. We have, it is true, in the activity of the salivary glands an analogous phenomenon to indicate--not, however, that of which we have just spoken. We might apply every conceivable form of stimulus which could possibly come into play in the act of eating, and yet would not obtain the slightest indication of secretory activity in the stomach. In this dog with a gastric fistula, and with also a divided œsophagus, I will try such an experiment, using the most effective chemical stimulus to the buccal mucous membrane, viz., acid solution. The secretion of saliva begins at once, as you see; the acid is, therefore, effective. From the stomach, however, in spite of continued excitation, no secretion results, although the acid, mixed with the saliva, is swallowed and flows out again from the upper segment of the œsophagus--that is to say, passes along precisely the same path that the food takes in sham feeding. We could experiment in the same way with a number of other substances: saline, bitters, pepper (strong local excitation), mustard, and so on, and always with the same results; a free secretion of saliva, but perfect quiescence of the gastric glands. We may even, with the same object, employ the soluble constituents of flesh in the form of a decoction, and likewise observe, in most cases at least, no sign of activity on the part of the gastric glands.