GENTLEMEN,--On the last occasion we made ourselves acquainted with the first normal impulse which, in the natural course of events, calls into activity the innervation apparatus of the gastric glands. This impulse is a mental one, and consists in a passionate longing for food, that which in every-day life, and in the practice of the physician, is called “appetite,” and which everybody, both medical and lay, endeavours carefully to promote. We may now venture to say explicitly, APPETITE IS JUICE, a fact which at once displays the pre-eminent importance of the sensation. Medical science endeavours to assist the debilitated stomach by introducing the active constituent of gastric juice--pepsin--from without, or by prescribing other remedies believed to promote its secretion. It is, however, of interest to follow our experimental investigation still farther. What position is to be assigned to the “psychic” or “appetite-juice”[30] in the course of normal gastric digestion? Is any definite _rôle_ to be attributed to it? What course does gastric digestion take when it is absent? Fortunately to all these important questions satisfactory answers are forthcoming by experiment. We have only to regret that these answers come so late. Let us recall to memory how the secretion of gastric juice proceeded after feeding with flesh or bread in the case of our dog with the isolated miniature stomach. The following are the quantities and digestive capabilities of the first two hourly portions of juice after the administration of 200 grams of flesh or bread (experiments by Dr. Chigin): ═════╤═══════════════════╦═══════════════════ │ Flesh. ║ Bread. Hour.├————————-┬————————-╫—————————┬————————— │Quantity │Digestive║Quantity │Digestive │of juice.│ power. ║of juice.│ power. —————┼————————-┼————————-╫————————-┼————————— 1st │12.4 c.c.│ 5.43 mm.║13.4 c.c.│ 5.37 mm. 2nd │13.5 ” │ 3.63 ” ║ 7.4 ” │ 6.50 ” ————-┴—————————┴————————-╨—————————┴—————————