1. Charcoal removes trypsin from solution. The amount removed depends on the order in which the solutions are mixed. The reaction is not reversible and is almost independent of the pH of the solution.
2. Charcoal which has been previously treated with gelatin does not remove trypsin from solution.
3. The reaction is not analogous either to the reaction between trypsin and the inhibiting substance of serum or to the reaction between solid protein and either pepsin or trypsin.