DECEMBER 29, 1899. ] 
their atoms are easily set in motion, we can 
further understand that, by thus lessening 
certain affinities in them, another grouping 
of atoms may result. 
Itthus becomes intelligible why one mole- 
cule of an enzyme can, like a machine,change 
innumerable molecules, one after the other, 
ofanother compound. The chemical changes 
produced consist either in depolymerization, 
as in the production of dextrin from starch, 
or in hydrolytic action, as in the conversion 
of maltose into glucose, or in a further split- 
ting combined with atomic migration, as in 
the production of amido-acids and bases 
from protein by trypsin. 
Such chemical action produced by the 
mere transmission of chemical energy by a 
certain substance, which remains chemically 
unaltered, but acts like a machine, are called 
catalytic. We know that such actions are 
produced by finely divided metals, by alka- 
lies and strong acids and that such are also 
produced by labile organic compounds. 
Thus, for instance, an aqueous solution of 
ethylaldehyde transforms dicyanogen rap- 
idly in oxamid without undergoing a change 
itself (Liebig). Finely divided nickel splits 
acetylene into carbon and hydrogen,* finely 
divided platinum splits hydrogen peroxide 
into water and oxygen, ete. 
We may now consider the third of the 
above questions: How can the specific action of 
the enzymes be explained ? How is it, for exam- 
ple, that diastase can saccharify starch but 
not inulin, that inulase can saccharify inulin 
but not invert cane-sugar, that invertase 
can invert cane-sugar but not milk-sugar ? 
Here the principle of the configuration of 
the molecules comes in. The closer the 
contact, the more perfect a transmission of 
energy is possible. The molecular adhe- 
sion, however, is enhanced by a certain co- 
incidence of the surface features of the 
molecules. The writer in the year 1893 
* Moissan and Moureu, Compt. Rend., Vol. 122, p. 
1240. 
SCIENCE. 
961 
applied this principle to explain the fact 
that certain alkaloids have in very small 
quantities an effect only upon certain nerves, 
but not on all nerves, nor upon glands or 
muscles.* Later on, E. Fischer applied 
the same principle to the specific action of 
the enzymes, adopting the comparison to 
lock and key. However, Fischer did not 
discuss at all the question how enzymes can de- 
velop their energy nor did Green in his 
recent work: ‘Soluble Ferments’ devote a 
single line to it. The action of enzymes 
might be distinguished as enzymations to 
separate them from true fermentations 
which are such actions of bacteria as are 
intimately connected with, and directly 
dependent upon their living protoplasm 
itself and not upon enzymes secreted. 
From the recent observation of Hduard 
Buchner that alcoholic fermentation is not 
directly connected with the life of the yeast 
cell, it does not necessarily follow that 
lactic, butyric, or acetic fermentations are 
mere enzymations. Besides this, A. Wrob- 
lewski} has in a recent very interesting 
article pointed out important differences 
between zymase and the ordinary enzymes. 
The expressed juice of yeast is always 
opalescent and loses its fermentative action 
when filtered perfectly clear. It further 
soon loses its action upon mere dilution 
with water and also upon addition of 14 
per cent. of neutral salts. Formaldehyde, 
as well as sodium nitrite destroy the activity 
of zymase more easily than that of the true 
enzymes. Twenty per cent. ethyl alcohol 
destroys the zymase but not yet the known 
enzymes. 
OsoarR Lorw. 
U. S. DEPARTMENT OF AGRICULTURE, 
WASHINGTON, D. C. 
* A natural system of poisonous actions, Chapter 
VI., Munich, 1893, Dr. E. Wolff, publisher. 
Tt Centralblatt fiir Physiologie, September, 1899. He 
also showed that white diastase can be precipitated 
by saturation with sulphates, invertase can not. 
