254 



glycerin too. In the photoplasm of Bacterium splendidum another factor occurs adap- 

 ted to a still unknown substrate deriving from peptone and mannite. Really these 

 still hypothetical substrates are but different luciferines in the sense of D u b o i s. 

 It should be borne in mind here that D u b o i s knows nothing at all of his luciferine 

 of the polades, 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. prodigiosum, where race formation easily occurs, a corresponding factor 

 analysis of the chromoplasm will be possible, since, according to former demon- 

 strations, 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 B ii c h n e r. 



In consequence of the foregoing it is clear that conceptions such as chromo- 

 plasm, photoplasm, alcoholprotoplasm etc., 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 for- 

 warded, 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 1 ). 



Cell -rv all factors are enzymes. 



For the higher plants and animals factor analysis is based on crossing experi- 

 ments 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 pro- 

 perties 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 sub- 

 stances. 



We saw how this principle may be applied to a physiological function ; that it can 

 likewise lead to the factor analysis of a morphological character I will now endeavour 

 tc show with regard to the cell-wall. 



The formation of the cell-wall is commonly considered as a function of the 

 parietal protoplasm and must necessarily repose on the action of factors or heredity 

 units. For some microbes this process is clearly caused by one or more enzymes and 

 this is distinctly the case when the wall substance consists of levulan. This matter 

 results from canesugar (and slow.er and less profusely from raffinose), but from no 

 other substances. It forms the cell-wall of many species of sporulating bacteria, such 



') This theory I first advanced, though with some doubt, in: Mutation bei Mikroben, 

 Folia microbiologica, Bd. i, pag. 2, 1912, but now the difficulties are overcome. 



