INTRODUCTORY
It has recently been asserted by a number of investigators that the antitryptic power of blood serum affords a reliable diagnostic criterion of the existence of cancer. It is the object of the present paper to record the results of a series of observations based on this new method, and to give a critical estimate of the value of these results from a practical and a theoretical point of view.It has been known for many years that blood serum is capable of inhibiting the proteolytic power of trypsin. First made by Fermi and Pernossi, this observation was at once confirmed by Camus and Gley, Pugliese and Coggi, and in Germany by Hahn; more recent observations by Kolaczek, Bittorf, Müller, Wiens and Opie, established the fact beyond question. Ascoli and Bezzola in 1903 found that the antitryptic power of the serum was notably and constantly increased in cases of