A Theory of Ferments and Their Action. 
31 
solely in the enormous surface exposed in proportion to weight and 
mass, is evidence that the arrangement of molecules in a substance that 
will expose a relatively large surface to molecular energy is a necessary 
.factor in the composition of ferments. 
THE SUBSTRATE. 
The relations in specific features that exist between a ferment and 
its substrate, and a ferment and its decomposition products, have been 
subjects of observation and of much discussion; but the causes of these 
relations have never been satisfactorily determined. A great advance 
in our knowledge of the nature of these relations was, however, made 
by Emil Fischer when he showed that sugars which are chemically alike 
do not respond to the action of the same ferment. Maltase, for example, 
splits up all the a-glucosides, but has no power on the b-glucosides; 
while another ferment — emulsion — breaks up the b-glucosides and has 
no influence on the a-glucosides. The two series of glucosides — the 
alpha and beta series — are chemical isomers, that is, the molecules of 
both series contain the same land and number of atoms, but the atoms 
occupy different spatial relations in the molecules of the two kinds of 
glucosides. Now Emil Fischer says that it is this matter of difference 
in spatial relations, which the atoms of the two series occupy, that 
causes them to respond differently to the action of the same fer- 
ment. But no clear explanation of this fact has been given, and it 
remains for the biophysical theory to point out how spatial arrange- 
ments of atoms in molecules may affect their vulnerability to ferments. 
The rationale of this has already been gone into in describing how and 
why molecular energy is determined by molecular structure. It may, 
however, be necessary to a clear understanding of the theory, to repeat 
that ferment energy of a molecule is an expression of its ether waves, 
but such energy is potential, and can not, therefore, do work until the 
molecules of a ferment are brought in contact with the molecules of 
another substance, a substrate, whose ether waves they may influence, 
in response to the principle of interference; when this occurs the poten- 
tial energy of the molecules is converted into dynamic energy. Maltase 
ferments the alpha, series of glucosides for the reason that the ether 
waves of the ferment and the glucosides coincide, and it does not fer- 
ment the beta series because there is no coincidence of ether waves, in 
this case, between maltase and the glucoside. The substrate to a fer- 
ment can not, therefore, be an indifferent substance; on the contrary, 
the principle of interference requires that the molecular structure of 
the substrate shall bear a definite relation to the ferment in a stereo- 
chemical configuration of its molecules, since a definite relation in 
