Enzyme Actions and Properties.

This volume is divided into two sections, one general and the other special. In the general section the development of the enzyme concept is presented, together with a criticism of the more recent views of Fodor. The colloidal character of enzymes, their probable molecular weights, amphoteric character, adsorption and elution properties, specificities and general methods of producing enzyme preparations are covered in general. In the treatment of the adsorption phenomena and the activation of proenzymes, the influence of Willstädter is obvious. Enzyme kinetics are treated with care and in considerable detail, but specificity is treated too briefly. In the special section a rather lengthy discussion on esterases is followed by one on proteases. In the latter the work of American investigators on pepsin and rennin is not referred to and the author appears to lean toward the view of the identity of pepsin and "lab." As one might expect, the