The demonstration of tryptic digestion by an activated serum

In the earlier publications it was shown, that the placenta in the Abderhalden reaction is not digested. 1 It was assumed then that the dialyzable split products of protein appearing during the test originate from the serum as the result of its autodigestion. 2 It was shown also that although the normal serum shows no digestive power, such tryptic activity may be demonstrated in any fresh serum if it is rendered active by the removal of its antitrypsin. 3 In the recent experiments we have succeeded in demonstrating the proteolytic activity of the serum of pregnant individuals after the removal of its antitrypsin with boiled placenta, by allowing such a serum to act upon the standard suspension of fresh placenta cells. The number of cells were counted on a Fuchs-Rosenthal counting chamber at intervals during the experiment, and it was noticed that the cells underwent disintegration, only when mixed with the serum previously exhausted of its antitrypsin, whereas the control mixtures containing the whole male or female serum or salt solution remained practically unchanged. Such a digestion of placenta cells is not specific, as we have also observed it with the male serum, deprived of its antitrypsin by a non-specific mechanism, such as adsorption by kaolin or starch, as well as by the extraction with chloroform.