Intestinal digestion seems little affected in achylia gastrica (Stockton,[84] Ehrman and Lederer,[85] Bayliss and Starling[32]). This may be due to other secretin stimulants as fats, or to the action of the nervous mechanisms (Meltzer[86]).

THE DESTRUCTION OF SECRETIN BY HUMAN GASTRIC JUICE

We have carried out in detail experiments on the digestive effect of human gastric juice on secretin. Our results in every respect confirm the findings of Lalou,[62] who worked with commercial pepsin and dog’s gastric juice, but are even more striking because of the much superior quality of pure human gastric juice.

Methods.—The human gastric juice was obtained from Mr. V., the gastric fistula case of our laboratory. The chemical and digestive characters of his juice are discussed in a recent paper.[87] In the different experiments, different samples of gastric juice were used. The secretin employed was always freshly prepared. Digestion was carried out in the incubator at 38 C. with the reaction of 0.4 per cent. acid, and the end of the period was marked by either boiling the mixture or (in the first two experiments) by turning the mixture alkaline. The action of the preparation, we proved, was not influenced by the method used. The dogs on which the preparations were tested were prepared for carotid blood pressure, injection into the external jugular vein, and cannula in the pancreatic duct, essentially the methods of Bayliss and Starling[32] being employed. The preparations were injected at body temperature after being neutralized and filtered. Except for the addition of normal salt solution instead of gastric juice, the control injections of secretin were submitted to exactly the same treatment as the other preparations.

Results.—Our results are embodied in Table 1. We assured ourselves before beginning the series that incubation of secretin with boiled gastric juice produced no change. It is to be noted in the table that each experiment is a unit complete in itself, beginning and ending with a control injection of secretin. Special attention is called to the marked destruction that follows contact of human gastric juice with secretin for merely one minute. In Experiment 4, using 1 c.c. of human gastric juice, the action fell to 14 drops from an original secretion of 21; in Experiment 5, using 8 c.c. of gastric juice, the action fell to 6 drops from an original secretion of 20. Of interest also is the rate at which we get complete destruction of secretin. This is practically 2 hours for 2 c.c. with secretin giving originally 110 drops (Experiment 2, Fig. 1), or 30 minutes for 5 c.c. with a secretin giving originally 53 drops (Experiment 6). These results are practically parallel, though they were obtained with different samples of gastric juice and in different experiments.

TABLE 1.—THE DESTRUCTION OF SECRETIN BY HUMAN GASTRIC JUICE

No. of ExperimentQuantity
of
Gastric
Juice
Used,
C.c.		Secretion of Pancreatic Juice in Drops
10 C.c.
Secretin
Control
—Beginning
Experiment		The Secretin After Incubation with Human Gastric Juice10 C.c.
Secretin
Control
—End of
Experiment
Dig. Time, HoursSecretion RateDig. Time, HoursSecretion RateDig. Time, HoursSecretion Rate
12 286 04    02  016
221102 711⁄2181 1841
32 401 7 3⁄4 7 1⁄4 831
41 21  1⁄211 1⁄412  1⁄601418
58 20  1⁄2 1 1⁄4 3  1⁄60 618
65 53  1⁄2 2..........

We also tried the effect of keeping the digestive time constant and varying the amount of gastric juice employed. Increasing the quantity of gastric juice used increases the quantity of secretin destroyed (Table 2).

TABLE 2.—EXPERIMENT 7*

PreparationPancreatic
Juice Drops
10 c.c. secretin20
10 c.c. secretin digested with 0.5 c.c. gastric juice15
10 c.c. secretin digested with 3 c.c. gastric juice13
10 c.c. secretin digested with 10 c.c. gastric juice 8