After Fermi and Pernossi, Camus and Gley, Pugliese and Coggi, and Hahn had drawn attention to the antitryptic action of normal blood serum, it was demonstrated by various observers that, under pathologic conditions, this may be either increased or diminished. Ascoli and Bezzola, more especially, were able to show that there is a marked increase in the antitryptic content of the blood serum in pneumonia up to the time of the crisis, while after the crisis, with the disappearance of the local symptoms, there is coincidently a marked decrease in the antitrypsin. Somewhat later Kolaczek, Bittorf, Wiens and others studied the antitryptic content of the serum in various diseases, finding a decrease in some and an increase in others. A systematic study of the question was, however, not made until quite recently, when Brieger and Trebing1 drew attention more particularly to the marked increase of the antitryptic content