On the Modification Of

An endeavor to find if specific meanings might be attached to the temperature characteristics of vital processes has led to the view 1 that common activities of organisms appear to be governed by the velocities of members of a system of chemical reactions, identified to the extent that they yield quantitatively concordant critical increments, which are repeatedly encountered in very different kinds of living matter (Crozier, 1925-26). Experimentally determining which of several possible critical increments a given phenomenon shall be made to exhibit thus signifies control of specific governing reactions (Crozier and Stier, 1924-25, a), and makes possible, even without great regard for the theory giving rise to it, a new type of analysis. Its development is facilitated by knowledge of instances in which it is possible to modify the temperature characteristic, even when no truly reversible determination may be attained. Several quite different possible kinds of modification can be predicted to occur, on the basis of what is already known of the temperature relations. I t will be shown that some of these possibilities are realizable. They may be roughly enumerated: (1) The velocity or the latitude of variation may be changed without change of increment; (2) a normal temperature characteristic