70 PHYSICAL CHEMISTRY IN MEDICINE. 



red-green reaction and the yellow-blue reaction as homo- 

 drome antagonistic ones, the mobile equilibria of which 

 can be pushed in opposite directions under the influence 

 of two catalyzers. But these reactions may at one time 

 take place in the one direction, at another in the opposite 

 direction, so that red and green can never be simultaneously 

 discovered in a color, no more than blue and yellow. The 

 black- white sensation would, on the other hand, represent 

 a heterodrome antagonistic reaction which, under the 

 influence of white light, moves along one course, but en- 

 deavors spontaneously to move back along another. As 

 these oppositely running components of the antagonistic 

 reaction can occur side by side, black and white can 

 be perceived simultaneously. 



With this we will bring our consideration o antag- 

 onistic reactions in living matter to an end. A more 

 detailed study of the questions which are involved is 

 reserved for a future paper. 



If, in conclusion, we look back once more over the 

 path that has been traversed, every step seems to indicate 

 that physico-chemical investigations of a substance that 

 is closely related to living matter are able to throw much 

 light upon the conditions that exist in living matter. In 

 fact, we see that the experimental results obtained in 

 this way pass over to meet those which direct observation 

 of the changes that go on in living matter yields. 



Investigations of this kind are well suited to show how 

 all biological methods are of the same value, in that 

 they leave no room for strictly mechanistic or vitalistic 

 tendencies. They form a mighty support for the true 

 scientific monism. The investigator, however, they fill 

 with a conception of those overpowering feelings of the 



