42 GENERAL AND PHYSICO-CHEMICAL. 



from the lactic-acid bacilli and beer vinegar bacteria, it is possible to 

 separate the specific fermentative principle of these organisms from the 

 living organism and to bring about changes with the dead organism 

 (E. BUCHNER, and MEISENHEIMER and GAUNT, HERZOG 1 ). The ques- 

 tion whether there exist ferment processes which, in PASTEUR'S sense, 

 are the result of the biological phenomena connected with the metab- 

 olism of the micro-organism and which we can directly identify with the 

 life processes, is very difficult to answer; hence for the present we have 

 no foundation for a sharp differentiation between the organized ferments 

 and enzymes. The metabolic processes of the living organisms which 

 we recognize as fermentation phenomena must as a rule be ascribed to 

 enzymes acting within the cell. If such processes are closely connected 

 with the life of the cell, then this is explained in part by the fact that 

 this special enzyme is produced only by living cells and in part by the 

 fact that it cannot be separated from the living cells or that it is readily 

 destroyed on the death of the cell. The names enzyme and ferment are 

 now generally used in the same sense. 



Formerly the view was generally accepted that ANIMAL OXIDATION 

 takes place in the fluids, while to-day we are of the opinion, derived 

 from the investigations of PFLUGER and his pupils, 2 that it is connected 

 with the form-elements and the tissues. The question as to how this 

 oxidation in the form-elements is induced and how it proceeds cannot 

 be answered with certainty. On the other hand, it is accepted that the 

 living protoplasm in some manner or other takes part, in which case the 

 oxidation processes must cease with the life of the cells while Ion the 

 other hand it has been found that certain oxidative processes can be 

 brought about by means of catalyts in the ordinary sense as well as by 

 enzymotic substances. If in the latter case the oxygen of the air is 

 directly transported to the oxidizable substance then we call this a direct 

 oxidation. Ordinarily the oxidative processes take place in the follow- 

 ing way. First a peroxide is formed by taking up oxygen, like in 

 the formation of hydrogen peroxide, H-O-O-H, which then transfers 

 oxygen to the oxidizable substance by aid of the mentioned substances. 

 In these cases the oxidation is indirect. All these oxidative processes 

 will be treated in detail in Chapter XVI. At the same time also other 

 enzymes will be discussed which decompose hydrogen peroxide, with 

 the setting free of oxygen, without oxidizing at the same time. These 



X E. Buchner and J. Meisenheimer, Ber. d. d. chem. Gesellsch., 36; 634 (1903); 

 and Annal. d. Chem. u. Pharm., 349; with Gaunt, ibid., 349; Herzog, Zeitschr. f. 

 physiol. Chem., 37. 



2 Pfliiger, Pfliiger's 'Archiv, 6 and 10; Finkler, ibid., 10 and 14; Oertmann, ibid., 

 14 and 15; Hoppe-Seyler, ibid., 7. 



