THE COLLOIDAL STATE. 65 



the two reactions occur independently of each other in 

 entirely separate localities. 



In heterodrome antagonistic reactions the acceleration 

 of the two reactions by one and the same catalyzer is 

 impossible; one catalyzer can be effective in only one of 

 the two reactions. A reaction can take place in one 

 direction, and at a certain stage for example, after a 

 condensation or polymerization through one enzyme be 

 switched into another direction; or the components of 

 the complex antagonistic reaction may be influenced 

 through two different catalyzers. Between two catalyzers 

 which displace the equilibrium of a homodrome antag- 

 onistic reaction in opposite directions, there exists a true 

 antagonism, while a complex antagonistic effect exists 

 where the two components of a heterodrome reversible 

 reaction are governed by two catalyzers. We may there- 

 fore distinguish also between simple and complex antag- 

 onistic ferments. 



A suitable example of a heterodrome antagonistic re- 

 action in metabolism is furnished by the formation and 

 destruction of uric acid in the animal body. The funda- 

 mental investigations of H. WIENER have thrown light 

 upon this subject. WIENER found that the " surviving" 

 ground-up pulp of different animal organs has the power 

 of both forming and destroying uric acid. In the liver 

 of the ox the two processes can take place simultaneously 

 and are, no doubt, dependent upon the activities of two 

 different catalyzers. As the sensitiveness of the two 

 catalytically acting substances toward heat is different, 

 the two chemical changes can be separated from each 

 other, the power to decompose uric acid being lost later 

 than the power to form it. That we have to do here 



