In this laboratory indol-acetic acid has been found in 21 per cent, of ninety-one urines of healthy normal persons.1 Of 174 urines from dementia praecox patients 48 per cent. contained indol-acetic acid. The occurrence of the compound in the urine seemed to be related to a peculiar constitutional condition.
Hopkins and Cole2 showed that B. coli, under partial aerobic conditions, would produce indol and indol-acetic acid from tryptophan. Salkowski3 showed that if indol-acetic acid were given by the mouth, it immediately appeared in the urine. Herter4 reported indol-acetic acid in the urine of an under-developed child suffering from an excessive and peculiar form of intestinal putrefaction. Putting these facts together, the natural conclusion would be that indol-acetic acid in the urine is a result of its production in the intestine by intestinal putrefaction of foods containing tryptophan. If this conclusion were true, indol-acetic acid, like