When deductions are made for the ammonia nitrogen of the juice, the formol-titrable nitrogen of Mr. V.'s appetite gastric juice varied from 3 to 9 gm. nitrogen per 100 c.c. The gastric juice of a second fistula case (Mr. E.) gave 7 gm. per 100 c.c. Four lots of dog's appetite gastric juice (Pavlov pouch) gave only 1 to 2 gm. of amino-acid nitrogen. It thus appears that normal human gastric juice contains slightly more amino-acid than ammonia nitrogen; but the greater part of the gastric-juice nitrogen is associated with more complex proteins.
Zunz reports that the amino-acid nitrogen (test meals) usually exceeds the ammonia nitrogen, and that both substances are increased in cases of gastric cancer. In three normal persons the maximum amino-acid was 10 gm. per 100 c.c. of gastric content, while in several gastric cancer cases it reached 15 to 20 gm. per 100 c.c. of content. But these figures cannot be directly compared with ours on pure gastric juice, because of the uncertain factors associated with the gastric contents following a test meal.