It may be objected that the peroxidase prop- erties of charcoal are due solely to a combination of catalase and oxidase properties. This cannot be the case in the oxidation of uracil by hydrogen peroxide in the presence of charcoalg as shown in a previous paper.'" There we also stressed the fact that colloidal charcoal has definite peroxidase activity while lacking marked catalase activity. The latter property has now been investigated for a large number of charcoal sols. ...
