OCTOBEE 12, 1900.] 



SCIENCE. 



553 



acids, and the phenomena of fermentation 

 under the action of organized ferments or 

 of enzymes. Various theories have been 

 proposed to explain this phenomenon, but 

 none of them seems to be universally ap- 

 plicable. Such theories as the temporary 

 formation and splitting up of an additional 

 product are not applicable in the case of 

 the action of platinum on hydrogen per- 

 oxide. Moreover, we have not only posi- 

 tive or accelerating catalysis, but also 

 negative or retarding catalysis, as in the 

 preservation of hydrocyanic acid by traces 

 of other acids, the retardation of the action 

 of free oxygen on sodium sulphite by traces 

 of alcohol, aldehyde and other organic 

 substances, and the influence of palladium 

 on sugar inversion. Such retarding actions 

 can hardly be explained on any hypothesis 

 yet offered. In recent years Ostwald has 

 contributed greatly to the possible future 

 solution of the problem by defining in what 

 it consists. I have stated that every reac- 

 tion proceeds to a state of equilibrium, 

 with a certain definite reaction velocity ; 

 the element of time is, therefore, an impor- 

 tant one in chemical changes. Ostwald 

 has pointed out that the influence of the 

 catalyzer is solely to modify the time 

 factor. Reactions which may proceed 

 ordinarily with a velocity so small as to 

 be inappreciable in a lifetime, laay be made 

 by the presence of a catalyzer to take place 

 in a few minutes or hours, and conversely, 

 reactions ordinarily proceeding rapidly may 

 be greatly retarded ; but whichever occurs, 

 the final state of equilibrium is the same, 

 whether the catalyzer be present or not ; it 

 acts solely by modifying the reaction ve- 

 locity. The knowledge of this important 

 generalization is essential to any further 

 progress. The importance for organic 

 chemistry of a thorough study of catalysis 

 can hardly be overestimated. < I need only 

 mention the important Friedel- Crafts reac- 

 tion, in which anhydrous aluminium chlo- 



ride is the catalyzer, and the reaction dis- 

 covered by Beckmann. Probably a large 

 portion of the chemical reactions known to 

 us can be controlled by the use of a suitable 

 catalyzer, being capable of acceleration or 

 retardation at will, while many which do 

 not occur with appreciable speed may be 

 brought about in a limited time. 



Especially important are the relations of 

 catalysis to physiological chemistry. The 

 unorganized ferments of the organism, the 

 enzymes, are simply catalytic agents. Be- 

 sides the well-known diastase, ptyalin, pep- 

 sin, and trj'psin, there are many others, the 

 importance of which is becoming more 

 manifest every day. Since Buchner's dis- 

 covery of zymase, the enzyme of the yeast 

 cell, there seems to be a tendency to at- 

 tribute nearly all the chemical processes of 

 the organism, even oxidation, to enzymes. 

 How far these views are correct is without 

 the scope of the present subject, and I can 

 allude to but a single recent discovery, the 

 importance of which can hardly be over- 

 rated. A. C. Hill * has recently shown that 

 the transformation of maltose into dextrose 

 under the action of the enzyme maltase is 

 in reality a reversible reaction. The equa- 

 tion is : 



C,,H,p, + H,0 = 2C,H,p,. 



Before the reaction is complete, the action 

 of the ferment ceases. If, on the contrarj', 

 we add the enzyme to a solution of dextrose, 

 a portion of the latter is converted into 

 maltose, the reaction being expressed by the 

 above equation read from right to left. 

 This is a striking confirmation of Ostwald's 

 view that the catalyzer simply influences 

 the rate, not the final condition, of the sys- 

 tem. It has been suggested, and the view 

 is a very plausible one, that in the living 

 organism the very same enzymes which 

 produce decompositions may under other 

 conditions, in conformity with the law of 

 *Journ. Chem. Soc. (London), 73. 634. 



