1283 
adapted to a still unknown substrate deriving from peptone and 
mannite. Really these still hypothetical substrates are but different 
‘Juciferines” in the sense of Dusors. It should be borne in mind 
here that Dusois knows nothing at all of his luciferine of the 
pholades, whereas regarding the photobacteria at least the substances 
are known from which they result. 
By multiplying the nutrition experiments it will be possible to 
come to a complete “factor analysis” of the photoplasm. For other 
bacteria the difficulties will be greater, but for B. prodiyiosum, 
where race formation easily occurs, a corresponding factor analysis 
of the “chromoplasm” will be possible, since, according to former 
demonstrations, it must quite like the photoplasm be regarded as a 
complex of heredity units possessing the character of oxidases. 
So we arrive also here at a result analogous to that already obtained 
for the alcohol function, which may be ascribed as well to ‘alcohol 
protoplasm” as to some enzymes, the zymase of BÜücHNer. 
In consequence of the foregoing it is clear that conceptions such 
as “chromoplasm’’, “photoplasm”’, ‘‘aleoholprotoplasm”’ ete., are not 
in contradiction with the wider view that considers the protoplasm 
in general as composed of enzymes, as they themselves are built 
up of these. 
There being nothing to object to the further generalisation of the 
view here forwarded, it is allowed to consider the heredity units as 
enzymes and these as heredity units, clearly two different names 
for the molecules or micells of the living part of the protoplasm. ’) 
Cell-wallfactors are enzymes. 
For the higher plants and animals factor analysis is based on 
crossing experiments between forms of which we wish to state by 
what and by how many heredity units they differ. For the bacteria 
and the other microbes, where for want of sexuality crossing is 
impossible, factor analysis is then possible when the factors of 
special properties can be recognised by race formation through 
mutation, which I already put forward before. The recognition of 
the heredity units as enzymes may likewise lead to factor analysis 
by applying the property of enzymes only to act on special 
substances. 
We saw how this principle may be applied to a physiological 
1) This theory I first advanced, though with some doubt, in: Mutation bei 
Mikroben, Folia microbiologica, Bd. 1, Pag. 2, 1912, but now the difficulties are 
overcome. 
82 
Proceedings Royal Acad. Amsterdam. Vol. NIX. 
