( 472 ) 



experiment is made without the water-current going through the 

 flax, a rich growth of all Ivinds of other bacteria will arise, but a 

 real accumulation of G. pectinovorum and a good rotting-process is 

 not obtained in the first two or three days. 



The cause of this striking phenomenon reposes exclusively on 

 the competition of the different microbe species. This is evident 

 from the fact that with pure cultures of 6^. ^><?c?moyt>;'?/m, even without 

 refreshing the water, a very good rotting is possible. The substances 

 removed from the flax by the water-current are not in themselves 

 prejudicial to G. pectinovorum, but they favour the growth of the 

 other species, in particular of the lactic-acid micrococci, so much more 

 strongly, that G. pt'ctinororum can develop only later and with very 

 great difficulty. It is also certain that the secretion of pectosinase in 

 the dilute liquid is more profuse than in the more concentrated 

 nutrient solutions. Thus we did not succeed in rotting flax by placing 

 it in dilute sterilised malt-extract with chalk, of about 2^ on the saccharo- 

 meter of Balling, which was in a vigorous fermentation by a 

 pure culture of G. pectinovorum. Evidently no pectosinase secretion 

 takes place under so favourable nutrient conditions. 



Hence, there is a double reason why extraction so much promotes 

 the rotting: the pectose bacterium gets the ascendency, and its faculty 

 of secreting pectosinase becomes active. 



If we compare tlie microscopic image of the bacteria (PI. Fig. 1) 

 of the flax, rotted after the current "experiment", with that, treated in 

 the usual way, after the white or blue rotting methods, one is struck 

 b^ the enormous diiference. In the latter case hardly anything is seen 

 but the foreign species and G. pectinovorum is scarcely detected ; 

 whilst in the product, obtained by the current-experiment G. pectino- 

 vorum is seemingly in pure culture ^). 



7. Simplification of the current-experiment. 



When the great importance for the rotting-process of extraction 

 of the flax-stalks and of aeration had been recognised, it was natural 

 to try whether the current-method could be replaced by a more 

 rational way of water-refreshing for the practice. 



This was effected in the following simple manner. 



After standing 24 hours on the flax, the water was completely 

 decanted off, so that all spaces between the stalks were drained and 

 could fill with air. Subsequently a new supply of water was provided, 

 either of fresh water of about 30' C. or of 2:ood rottino;- water of 



1) Compare further § 12. 



