Abstract
Within the past two years, the antitryptic activity of human serum has been the subject of a considerable number of studies, and it has apparently become established that this property of the serum varies within wide limits in certain conditions of disease, being characteristically increased in all cachexias, notably so in cancer. Two methods have been employed in this study, which are exactly the same in principle, in that they are based on the use of a series of mixtures of trypsin in solution, and of the serum, the end-point in the one method being denoted by the smallest quantity of serum which totally inhibits the digestive action of the trypsin, on a plate of coagulated beef-serum, while, in the other, it is the lowest proportion of trypsin which completely digests the medium, namely, a solution of casein. It is evident that by either of these methods it is possible to determine only an approximate value of serum, lying between the two dilutions, just above and just below the so-called end-point. Moreover, the end-point itself is in neither method sharply defined. If, to these uncertainties, is added the fact that the media of digestion are subject to certain uncontrollable variations, such as the inherent differences in sera,—it will be manifest that the methods are materially lacking in exactness. Consequently, the results have been divergent.
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