1913] William N. Berg 445 



water, it would pass thru, if fibrin were placed in the water. He 

 explains this as follows (1872, p. 443) : 



Der Vorgang erklärt sich, wie ich glaube, durch die Annahme, dass 

 das Fibrin das Pepsin sehr energisch absorhirt, dass auch beim Fehlen 

 jenes minimale Mengen diffundiren, die Diffusion aber durch die Ab- 

 sorptionsfähigkeit des Fibrins beschleunigt und verstärkt wird. 



It is quite possible that the principle of this experiment might 

 have a wide application, i. e., that the diffusibility of many sub- 

 stances (now regarded as indiffusible) might be greatly increased 

 by placing material in the diffusion medium which was not soluble 

 in the medium but which could combine with the substance whose 

 diffusibility was under investigation. 



The above mentioned observations by von Wittich, on the 

 diffusibility and absorption of pepsin by fibrin, have recently been 

 used by several investigators. Beginning with the work of Abder- 

 halden and Steinbeck,^^ Abderhalden and his co-workers have 

 publisht a long series of researches on the adsorption of enzymes by 

 proteins. In none of these publications that the writer has seen is 

 there any allusion to the fact that the principle involved was not 

 new. The name of von Wittich was not mentioned. From their 

 papers one might justly infer that Abderhalden and Steinbeck be- 

 lieved that they had discovered the adsorption of pepsin by pro- 

 teins, when they were, in fact, using a principle discovered in 1872 

 by von Wittich. To a lesser extent this criticism applies to Hedin, ^^ 

 in whose several publications von Wittich is not mentioned, altho 

 many of the experiments and conclusions of Abderhalden and his 

 co-workers, and of Hedin, can be found in von Wittich's paper. 



In a very interesting manner Chodschajew^^ discusses the work 



of von Wittich on the diffusibility of pepsin, some of which 



Chodschajew repeated. Dauwe^^ mentions von Wittich as the first 



to observe the adsorption of pepsin by fibrin. 

 Washington, D. C. 



"■^ Abderhalden and Steinbeck: "Beitrag zur Kenntnis des Pepsins und der 

 Salzsäure," Ztschr. f. physiolog. Chemie, 68, p. 293, 1910. 



^ Hedin : " Observations on the action of trypsin," Joiir. of Physiol., 32, 

 p. 468, 1905 ; Biochemical Journal, 2, p. 81, 1907. 



"Chodschajew: " Les enzymes sont-elles dialysables ? " Archives de Physiol- 

 ogie normale et pathologique, 1898, p. 241. 



" Dauwe : "Ueber die Absorption der Fermente durch Kolloide," Beiträge zur 

 chemischen Physiologie und Pathologie, 6, p. 427, 1905. 



