An Antitryptic Effect of Charcoal

By chance I recently observed that charcoal, when added to a digesting fluid of trypsin and casein, produces a very marked diminution of the tryptic effect. There can hardly be any doubt that this depends upon the trypsin being taken up by the charcoal, thus being prevented from acting upon casein. It is a well known fact that charcoal readily condenses gases on its surface, and likewise takes up colouring matters from solutions. That other solid substances and especially hydrogels, have got the power of taking up crystalloids from their solutions has been pointed out by several investigators (v. Bemmelen,' Schmidt,' Biltz,3 Bayliss,4 and others). This process has been termed adsorption (Du Bois Reymond, Ostwald). As to the laws of adsorption very little is known. Henry's rule, which has been found to be valid for the distribution of a soluble substance between two fluids, which implies that the ratio between the concentration in the two solvents is a constant ( c1 = k), when equilibrium has been reached, does not apply to the adsorption. In the case of adsorption, a state of equilibrium seems to be arrived at sooner or later; if Cads is the concentration in the solid substance and Cfl the concentration in the fluid, then Cads is not a constant, Cfl but diminishes as the total amount of the originally dissolved substance is increased. This means that the solid takes up relatively more from