Note:  Do not rely on this information. It is very old.


Catalysis is a term employed to denote a class of chemical actions which are induced by the presence of some substance - the catalytic agent - which does not itself, however, undergo any perceptible change. Many can be explained on the supposition of the formation and subsequent decomposition of intermediate products in which the catalytic agent takes part; but in many cases the exact nature of the influence exerted by the agent is not yet understood. Finely-divided powders, as platinum black, frequently condition catalytic actions, and the influence of acids in causing the inversion of cane sugar, or the conversion of starch into grape sugar, may also be referred to this class.