256 



from carbohydrates, still quite another factor operates here is proved by the following 

 observations. By feeding this bacterium with glucose, cane-sugar, maltose or lactose, 

 wall slime is readily yielded. In several other species, for instance Aerobacter viscosiis 

 and Bacillus polymyxa we find the same. But B. prodigiosum can besides produce 

 slime from albuminous substances such as gelatin and peptone, which B. polymyxa and 

 A. viscosus cannot. As now it is quite unacceptable that one and the same factor could 

 be able to produce cellulose slime as well from proteids as from carbohydrates, B. prodi- 

 giosum must possess a specific factor able to split off from the albuminous matter an 

 enzyme-substrate, converted, into cellulose slime by the wallforming factor. But this 

 proteid-splitting factor does not exist in B. polymyxa and A. viscosum. B. prodigiosum 

 viscosum is thus a mutant, distinct by at least two factors from B. prodigiosum itself, 

 which produces no slime at all, neither from carbohydrates nor from proteids. It 

 must thus be possible to detect another still unknown mutant lacking the factor to 

 produce from proteids a substrate that can be converted into slime, that is a mutant 

 capable to produce slime from carbohydrates only and not from proteids. 



A great number of other examples might be added demonstrating that the specu- 

 lations about the heredity units or factors have relation to enzymes. 



Limitation of the enzyme conception. 



In my opinion the preceding may lead to a better enzyme conception than the 

 existing. I will try to elucidate this by a few instances taken from the cecidia or 

 galls and the substances called ferments in immunology. 



Elsewhere I pointed out that the change of the plant at gall-formation is not 

 hereditary. From the galls of Nematus viminalis, kept on moist sand, quite normal 

 roots of the gall-bearer Salix purpurea, and from those of the gall-fly Neuroterus 

 lenticularis on oak-leaves, quite normal oak roots may arise 1 ). 



From the axil-buds of the willow-rose, caused by Cecidomya rosaria on Salix 

 alba, I have cultivated quite normal willow trees; likewise I grew normal plants of 

 Poa nemoralis from the bud in the remarkable gall of Cecidomya poae, whose strange 

 metamorphic roots readily develop into normal roots, when the whole gall is planted 

 in earth 2 ). By strongly pruning the twigs of Rosa canina whereon Bedeguars deve- 

 loped, caused by the gall-fly Rhodites rosac, the wonderful appendices of this gall 

 changed into long-petiolated, simple, green leaflets, whose anatomic structure and 

 external appearance were quite identic with those of the leaf on which the gall 

 originates. 



These instances, to which I could easily add others, show that in the formation 

 cf galls two groups of substances are concerned: the protoplasm of the plant, consi- 

 sting of the unchanged heredity units, and substances deriving from the egg of the 

 gall-animal, or from the larva of Cecidomyia, which evidently have the character of 

 enzymesubstrates. It is however clear that the heredity units concerned in the mor- 

 phologically higher galls, multiply more intensely, in any case become more numerous 



*) Only very few Lenticulariss^s possess this disposition, which is probably connected 

 with the spot where the gall grows on the leaf. 

 -) Botanische Zeitung 1886. 



