442 The Definition of Enzyme Action [April 



Partly on accoimt of their obscure places of publication, and 

 partly on account of fanlty references in the literature, Ostwald's 

 original definitions were f ound with some difficulty : 



Katalyse ist die Beschleunigung eines laugsam verlaufenden chem- 

 ischen Vorganges durch die Gegenivart eines fremden Stoffes. . . .* 



Man nennt die Stoffe, welche solche Änderungen der Geschwindig- 

 keit bewirken, Katalysatoren, und zwar positive und negative, je nach- 

 dem sie Beschleunigungen oder Verzögerungen hervorbringen. Der 

 Begriff der Katalysatoren hat erst in neuerer Zeit diese bestimmte Defi- 

 nition erfahren (Ostwald 1894). . . .^ 



Since Ostwald himself dates the definition of catalysis at 1894, 

 it would naturally be assumed that that date is the correct one. 



While engaged, about five years ago, in a study of enzyme ac- 

 tion, the attention of the writer was drawn to a paper publisht by 

 von Wittich,*^ not alone because of the ingenuity of the experi- 

 mental work described therein, but especially because of von 

 Wittich's striking conclusion (p. 469) regarding the nature of 

 peptolytic action: 



Es bleibt daher nichts anderes übrig, als anzunehmen, dass die 

 Säure allein hinreicht, um jene bekannte Umwandlung des Fibrins ein- 

 zuleiten, dass aber die Gegenwart des Pepsins letztere wesentlich 

 beschleunigt. 



The "Umwandlung" referred to is the transformation of fibrin 

 into peptone. 



von Wittich had observed that fibrin was slowly transformed 

 into peptones by hydrochloric acid and that this transformation took 

 place much more rapidly in the presence of pepsin. Other investi- 

 gators had made the same Observation, but without correctly under- 

 standing the role of the enzyme, as von Wittich apparently did. 



These facts were mentioned about four years ago by the writer, 

 who believed that von Wittich had antedated Ostzvald in the defini- 

 tion of catalysis. Until recently, lack of opportunity prevented a 

 sußiciently careful search of the literature on this particular point. 



* Ostwald : Ztschr. f. physikal. Chemie, 15, p. 706, 1894. 



'Ostwald: Grundriss der allgemeinen Chemie, 3 Aufl., p. 515; Leipzig, 1899. 

 ' von Wittich : " Weitere Mittheilungen über Verdauungsfermente," Archiv 

 f. d. gesammte Physiologie, 5, p. 435-469, 1872. 



