APPENDIX 287 



affinity, another force is active in chemical reactions: this he called cata- 

 lytic force. As an example he used Kirchhoff's discovery of the action of 

 dilute acids in the hydrolysis of starch to dextrose. In this process the 

 acid is not consumed, hence Berzelius concluded that it did not act through 

 its affinity, but merely by its presence or its contact. . . . He then suggests 

 that the specific and somewhat mysterious reactions in living organisms 

 might be due to such catalytic bodies as act only by their presence, mthout 

 being consumed in the process. He quotes as an example the action of 

 diastase in the potato. 'In animals and plants there occur thousands 

 of catalytic processes between the tissues and the liquids.' The idea of 

 Berzelius has proved fruitful. , . . We now know that we have no right 

 to assume that the catalytic bodies do not participate in the chemical 

 reaction because their quantity is found unaltered at the end of the reac- 

 tion. On the contrary, we shall see that it is probable that they can ex- 

 ercise their influence only by participating in the reaction, and by form- 

 ing intermediary compounds, which are not stable. The catalyzers may 

 be unaltered at the end of the reaction, and yet participate in it. 



"In addition we owe to Wilhelm Ostwald^ the conception that the cata- 

 lyzer does not as a rule initiate a reaction which otherwise would not occur, 

 but only accelerates a reaction which otherwise would indeed occur, but 

 too slowly to give noticeable results in a short time." 



NOTE V 



THE CAUSES OR AGENTS OF SPEED AND ORDER IN THE REACTIONS 

 OF LIVING BODIES — ENZYMES, COLLOIDS, ETC." 



" There is still another feature of cell chemistry which must strike even 

 the most superficial observer, and that is the speed with which growth 

 and the chemical reactions occur in it. . . . Starch boiled with water 

 does not easily take on water and split into sweet glucose, but in the plant 

 cell it changes into sugar under appropriate conditions very rapidly. How 

 does it happen then that the chemical changes of the foods go on so rapidly 

 in living matter and so slowly outside? This is owing to the fact, as we 

 now know, that living matter always contains a large number of sub- 

 stances, or compounds, called enzymes (Gr. en, in; zyme, yeast; in yeast) 

 because they occur in a striking way in yeast. These enzymes, which are 

 probably organic bodies, but of which the exact composition is as yet 

 unknown, have the property of greatly hastening, or as is generally said, 

 catalyzing, various chemical reactions. The word catalytic {kata, down; 

 lysis, separation) means literally a down separation or decomposition, but 



'Ostwald, W., Lehrhnch dcr aUgemeinen Chemie, vol. II, 2d part, p. 248, 1902. 

 2 Mathews, Albert P., Physiological Chemistry, pp. 10-12. 



