Observations on the nature of the antitrypsin of the serum

In a previous communication to this society, it was shown by the authors that the viscosimeter offers a method for determining the anti-tryptic activity of serum which is extremely accurate, delicate and constant in its results. Further study by means of this method has revealed the fact that this so-called anti-tryptic activity is in reality very much more complex than had hitherto been suspected. If a series of intracellular enzymes are prepared from various human organs and from carcinomata, according to the method of Wiechowski, by drying, it becomes possible to test the inhibitory action of any given serum against each of these enzymes by the use of the viscosimeter. This has been done by the authors with a considerable number of sera. The resulting figures, which have been constant in successive experiments, demonstrate that the inhibitory value of each serum is distinct and different for each of the enzymes tested. These differences are extreme, inasmuch as a given serum may show an inhibition of only five per cent. of the total digestion against one organ enzyme, and as much as 95 per cent. against another. With a second serum, again, these relations are found reversed.