92 LIFE: ITS NATURE AND ORIGIN 



way that one calls by the name analysis the decomposition of 

 bodies by chemical affinity." 



It is interesting to read the reaction of contemporaries of Berzelius 

 to his views: 2 



"On Catalysis and Catalytic Force, by Berzelius. As is well known, 

 in the action of gold, etc., on hydrogen peroxide, of acids on sugar, of 

 sulfuric acid on alcohol, (according to Mitscherlich), of spongy plati- 

 num on hydrogen, etc., we have recently had examples, even though 

 they are not all of like cogency, of the existence of various influences 

 that substances exert on each other, which differ from heretofore 

 known types of chemical activity. That is, there evidently are sub- 

 stances which possess the power to decompose into their constituents 

 other materials with which they come into contact, without entering 

 into combination to any appreciable extent with the new compounds 

 formed. This type of chemical activity has been known as decompo- 

 sition by mere contact. Berzelius proposes to call this power of sub- 

 stances catalytic power, and the process due to it catalysis. He does 

 not mean to say that the force is a new one, but is convinced that we 

 are here dealing with a special form of expression of known forces. 

 Catalytic force seems to reside in the power of the substances in ques- 

 tion to arouse in other substances, by their mere presence, affinities 

 according to which the elements of the compound substance rearrange 

 themselves, so as to attain complete electrochemical neutralization. 

 This is analogous to the action of heat, and the question arises 

 whether, as in the case of heat, a different degree of catalytic force will 

 produce different catalyzed products from various substances, and 

 whether different catalyzers will not produce different catalytic results 

 with a given material. This cannot now be answered, for according 

 to present experience, every substance having catalytic power appears 

 to have it only as against certain other substances. 3 



Since many biological catalytic changes occur in the colloidal 

 zone, the following excerpts from earlier publications are given, 

 before considering some more recent aspects of catalysis. We 

 begin with a fundamental paper of Thomas Graham: 4 



"The property of volatility, possessed in various degrees by so 

 many substances, affords invaluable means of separation, as is seen in 

 the ever-recurring processes of evaporation and distillation. So 

 similar in character to volatility is the diffusive power possessed by all 

 liquid substances that we may fairly reckon upon a class of analogous 

 analytical resources to arise from it. The range also in diffusive 

 mobility exhibited by different substances appears to be as wide as the 

 scale of vapor tensions. Thus the hydrate of potash may be said to 



