CHAPTER XI 



ELECTRICAL AND OTHER FACTORS IN THE 

 CATALYTIC ACTION OF PROTOPLASM 



Of the conditions, other than temperature and tlie 

 presence of catalyzers, influencing reaction-velocities, 

 Hght and other forms of radiation and electricity are 

 the most important. Apparently all chemical reactions 

 are influenced by radiation of appropriate wave-length, 

 and the acceleration caused under these conditions is 

 called ''photocatalysis." It differs, however, from the 

 chemical forms of catalysis in that energy is added to 

 the reacting system from without; in this respect the 

 conditions may be compared to those present when an 

 electric current is passed into a solution from an electrode ; 

 at the surface of transition between solution and electrode 

 chemical reactions are induced (electrolysis), the effect 

 depending directly on the quantity of electricity (i.e., 

 number of electrons) transferred between the molecules 

 of the electrode and those of the solution. Similarly 

 the chemical effect of hght is referred to faciHtation of the 

 transfer of electrons between molecules. In virtue of 

 its physical character as electromagnetic oscillation, 

 light alters the range of movement of the electrons; and 

 when the periodicities of electron motion and ether- 

 vibration correspond, this range may be increased to a 

 degree sufficient to enable adjacent molecules to interact. 

 The electrons affected are apparently the valence or 

 combination electrons of the molecules concerned. 

 The chemical action of light is thus ultimately to bo 



235 



