At this stage the preparation resembles a tube with a cannula in each end.The preparation is clamped in a vertical position to a ring stand, and connected to a light lever by means of a thread. An end of the ligature about the atrio-ventricular junction is a convenient place to attach the thread to the atrium. In the resulting preparation, oxygenated Lockds solution at 36 to 37°C flows through one cannula and out the other. The various pressure levels are approximately those shown in the diagram; the chief aims in adjusting these levels are to have the atrium moderately distended and to have sufficient Loclte's solution flowing through the preparation. (I have used about 10 cc per minute).The preparation will continue to beat with a rather constant rate and amplitude for several hours. It responds to changes in the ionic composition of the Loclte's solution and to epinephrine in the expected manner. Other substances have not been tried. The advantages of this preparation are its simplicity and durability.The 2 cannulae are now loosely tied together.
Although the association of high gastric acidity with certain cases of gastric and duodenal ulcer has long been recognized, the question of whether there are any findings on gastric analysis constant enough to be of real diagnostic value has never been settled. The figures in the literature cover a wide range; in most series of ulcer cases hyperacidity is said to have been present in 30 to 70 per cent of the patients, whereas the remainder showed normal or subacidity. Palmer (1) has recently reviewed the question of anacidity with gastric ulcer. Some writers would relate the tendency to hyperacidity with position of the ulcer near the pylorus or with other factors. Hurst (2) is impressed by the occurrence of duodenal ulcer only in people who already have a hyperacidity. Brown (3) has recently summarized the question as follows: "Somewhat less than 50 per cent of patients show high normal or hyperacid conditions. In rather more than 50 per cent of cases the figures are well within normal limits; occasionally subacidity occurs and rarely anacidity."In regard to the volume of secretion even less definite information is available. The presence of large volumes has been assumed in certain instances of ulcer but the absence of methods for volume determinations has made any accurate comparisons with the*normal impossible.In summary, then, the general implication of the literature is to the effect that no constant or characteristic findings on gastric analysis are associated with peptic ulcer.In a series of recent papers, Bloomfield and Keefer (4) draw attention to the inadequacy of the current methods of studying gastric function by means of the ordinary fractional test. Using a new procedure which made it possible to estimate, under uniform conditions 511
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