I.
In 1909 Neubauer and Fischer inaugurated the use of the dipeptid, glycyltryptophan, for the detection of peptid-splitting power in stomach contents, with special reference to the diagnosis of carcinoma. Their report called forth a shower of comments. It is not necessary to give a detailed account of the work, since this has been done repeatedly. But it may be recalled that it was based on an idea of Friedrich Müller that stomach contents from carcinoma patients could carry protein cleavage beyond the point at which normal peptic digestion ceases, and that this power was due to the presence in cancer tissue of an enzyme which could be secreted into the stomach.Emerson showed that malignant growths actually contain an enzyme capable of splitting protein beyond the albumose phase, and in greater strength than that seen in benign growths, normal tissues, or in blood. He found similar properties in gastric