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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 x
) . 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
1
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.
plivMol. f.’hern., 37.
2
Pfliiger, Pfiuger’s ’Archiv, 6 and 10; Finkler, ibid., 10 and 14; Oertmann, ibid.,
14 and 15; Hoppe-Seyler, ibid., 7.
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