Page:Defensive Ferments of the Animal Organism (3rd edition).djvu/85

 juice on the same peptone. It was possible to show that the decomposition in both cases was very similar, i.e., that the initial rotation varied in the same direction and to the same extent, whether the plasma of specially treated animals was used, or the active extract of yeast.

The following experiment proved, with exceptional clearness, that the plasma of an animal, when specially treated, actually reduces proteins. The plasma was mixed with gelatine or with white of egg, and the mixture was placed in a dialysation tube. Very shortly the presence of peptones could be demonstrated in the outer fluid—distilled water being chosen for this purpose—by means of the biuret reaction. But when plasma of normal animals was mixed with albuminous bodies and placed in a dialysation tube, no substances giving the biuret reactions could be traced in the outer fluid, even after standing for many days. Finally, it has been proved quite recently that, by mixing the plasma or serum of specially treated animals with albumen, the nitrogenous contents of the outer fluid increase to a considerably greater extent than when the plasma of normal animals and albumen are mixed together. In the last case the increase of nitrogen in the outer fluid is no greater than when the same quantity of plasma is brought into the dialysation tube by itself, i.e., without addition of albumen. It must be understood