690 
from, and give aid to, several other hypo- 
theses—it possesses a wide range of appli- 
eability. 
In 1892, our esteemed colleague, Professor 
J. W. McLaughlin, in his book on ‘ Fer- 
mentation, Infection and Immunity,’ elab- 
orated a‘ Physical Theory,’ a quotation 
from which is here presented. After de- 
veloping the modern conception of complex 
molecules, Dr. McLaughlin goes on to say: 
“¢ When we add to this conception of atomic 
and molecular union, that of atomic vibra- 
tions in unvarying periods of time which 
are distinctive of each kind of atom, and 
that of ethereal wave-motions vibrating in 
equal periods with the atoms that produce 
them, the law of ‘ interference’ enables us 
to understand how atomic wave-motions 
may be supplemented or antagonized by 
other atomic wave-motions, and how mo- 
lecular wave-motions may, likewise, be 
similarly influenced by other molecular 
waves; that, in fact, the molecular waves 
which give a substance its energy will vary 
with molecular grouping. Now it is in 
these principles of molecular dynamics, and 
in chemistry and biology, that, we believe, 
is to be found the explanation of cell metab- 
olism—constructive and destructive—of 
fermentation, of infection and immunity.” 
On page 66, he says: ‘‘It is only when the 
molecular vibrations of a ferment, whether 
this be a living, organized ferment, or a 
non-living, unorganized ferment, coincide 
with those of a fermentable substance, that 
the latter may be disrupted by. the former, 
and fermentation ensue.’’ While these two 
quotations do not adequately present Dr. 
McLaughlin’s theory, they suggest a con- 
necting link with the physical hypothesis 
of de Jager. 
“Starting with Naegeli’s view that fer- 
menting yeast-cells emit vibrations which 
pass out of the cells and decompose the 
sugar in the solution surrounding them, de 
Jager suggests that the enzymes may be 
SCIENCE. 
[N. 8S. Vou. XIII. No. 331. 
regarded not as substances at all, but as 
the vibrations themselves, that is as prop- 
erties of substances rather than material 
bodies.”” He compares them to light, elec- 
tricity, magnetism. Fermentation does not 
depend upon chemical action of a molecu- 
lar substance, but chemical transforma- 
tions are brought about by physical forces. 
Maurice Arthus has very ingeniously elab- 
orated the theory of de Jager. 
O’Sullivan and Tompson have shown 
that invertase is capable of inverting more 
than 100,000 times its own weight of cane 
sugar without exhausting itself; and Tam- 
man proved that under proper conditions 
the enzyme is decomposed during its ac- 
tivity with extreme slowness. These reac- 
tions find their parallel in the action of 
nitric oxide in the manufacture of sulphuric 
acid, and in the action of sulphuric acid in 
the production of ethyl oxide ; and Bredig 
and von Berneck have recently shown that 
“one gram-atom (193 grams) of colloidal 
platinum diffused through seventy million 
liters of water shows a perceptible action 
on more than a million times the quantity - 
of hydrogen peroxide.” 
In these four instances it will be observed 
that the invertase, nitric oxide, sulphuric 
acid, and colloidal platinum acted solely in 
the capacity of catalyzers, that is, they 
modified the time factor of the reaction 
—the positive catalyzers accelerating, and 
the negative catalyzers retarding, the ve- 
locity of the reactions. Catalyzers, then, 
serve in the capacity of liberating impulses. 
That zymohydrolysis is a chemical action 
finds further support in the recent work of 
A. Croft Hillon‘ Reversible Zymohydroly- 
sis.’ By varying the concentration of mix- 
tures of glucose and maltose he found that 
the equilibrium point of these two sugars 
was reached when 85.5% of glucose and 
14.5% of maltose were present. Increasing 
the glucose beyond 85.5% sent the hydrol- 
ysis one way, and the reaction reversed 
