In our tests the digestion mixture was made up of 1 c.c. gastric juice and 15 c.c. N/10 HCl. The egg albumin in the Metts tubes was coagulated in boiling water for 10 minutes. The digestion time was 24 hours at 370 C. Under these conditions the pepsin concentration of the gastric juice of Mr. V. showed the following figures: appetite juice, 6j to 7\ mm. digestion; continuous secretion, 6 to 7 mm. digestion; contents of empty stomach, 3 to 4 mm. digestion. The results are stated in the length of albumin column , actually digested, because, according to Cobb, the law of Schutz does not hold for pepsin in concentrations that digest more than 4 to 5 mm. in 24 hours.
The appetite gastric juice of Mr. E., our second gastric-fistula case, when tested as above in 14 experiments, showed a pepsin concentration of 5 to 7 mm. with an average of 6 mm., a slightly lower value than the gastric juice of Mr. V. The pepsin concentration of the gastric juice of normal dogs runs somewhat lower, or 2 to 5 mm.
When the Metts tubes are placed in 16 c.c. of undiluted human gastric juice (appetite secretion) the digestion in 24 hours at 370 C. varies from 12 to 16 mm., or only twice the quantity digested in the dilution of 1 c.c. juice to 15 c.c. N/10 HCl. This seems to indicate that in normal gastric juice the pepsin is present in excess of the needs or at least far in excess of that needed in economic digestion.
The U.S. Pharmacopeia defines "100 per cent pepsin as a preparation capable of digesting three thousand times its own weight of finely divided egg white (coagulated) in three hours." The Pharmacopeia test is carried out as follows: 10 gm. of boiled white of egg is macerated through a No. 40 filter and placed in 40 cc 0.3 per cent HCL, 3$ mgr. dried pepsin added, and the mixture incubated at 52° C. for 3 hours, with occasional stirring. After being treated in this manner, there is only a very small residue of undissolved egg white at the end of three hours, but the procedu: of measuring the amount of this residue does not yield very accura results.
This test was applied to six different lots of appetite gasti juice of Mr. V. Under the foregoing conditions, i to i J c.c. appeti gastric juice digested io gm. of coagulated and finely divided ej white in 3 hours practically as completely as is done by 3J mj " 100 per cent pepsin." As defined by the U.S. Pharmacopeia, 1 c of human gastric juice must therefore contain 3J mgr. pepsin, 100 c.c. of the juice, 35 mgr. pepsin. We have seen that the appeti gastric juice of man contains about 400 mgr. organic material p 100 c.c. That is, according to the Pharmacopeia definition, on about 10 per cent of the organic matter in the human gastric jui is pepsin.
It has been shown that an adult normal person, if hungr secretes 600 to 700 c.c. gastric juice after an average palatab dinner, or a total of about 1,500 c.c. gastric juice in 24 hours. Thi is to say, there is a secretion of 240 to 250 mgr. pepsin per dinne capable under proper conditions of digesting from 630 gm. to 7; gm. of protein (coagulated and finely divided egg albumin) in hours; and the total pepsin secretion in 24 hours is 525 mg capable of digesting 1J kg. proteins (coagulated eggwhite) in 3 hour
It is therefore clear that the normal human stomach secreti pepsin far in excess of the actual needs of gastric digestion, or, mo: precisely, far in excess of what can be used advantageously undi ordinary conditions of gastric digestion. When the. boiled ej white is broken up in larger pieces, such as occurs in ordinary rapi mastication, 1 c.c. of gastric juice requires 6 to 10 hours for complei digestion.
This great excess of pepsin in normal gastric juice probabl explains the clinical findings of great reduction in pepsin contei without any evidence of impaired gastric digestion. It probabl also explains, in part at least, the practical uselessness of commerci; pepsin as a therapeutic measure in gastric disorders.