( 471 ) 



If the rotted bark of tlie flax, or the pith, or the juice, contained in 

 the rotted stalk, is microscopically examined, we find there accumulated 

 the above mentioned verj characteristic Gramdobacter ijectlnovorum 

 (Plate Fig'. 1), which has supplanted nearly all other microbes and 

 which literally fills up the intercellular spaces {(rp Fig. 2), in many 

 places quite co^■ers the surfjice of the fibres and has, moreover, com- 

 pletely dissolved the thin-walled cells of the secondary rind, and 

 thereby freed the bast-bundles from the wood. In an iodine solution 

 this bacterium turns deep blue over nearly its whole length in con- 

 sequence of its amount of granulose. 



This is a so-called anaerobe. From the experiment described, where 

 an aerated water-current incessantly flows around the flax, it follows, 

 however, that a fair amount of air is of no prejudice to its develop- 

 ment ; and a more minute observation shows that here, too, as 

 with all other anaerobes, a limited aeration is not only harmless, 

 but beneficent, and even necessary to make the growth go on in 

 the long run. 



Our observation that the water of the Leie, near and at Courtray, 

 is strongly polluted by sulphuretted hydrogen, induced us to add 

 c. a. 50 mgrs. of H'S per 1. to the water for our rotting-experiment, 

 by which even in the rotting-w^ater flowing off a little H'S might be 

 detected. The rotting was decidedly retarded by this addition and 

 was less complete than in absence of sulphuretted hydrogen ; yet, 

 G. pectinovorum had strongly accumulated, though less profusely 

 than commonly. 



Quite otherwise was the effect of KNO°. If 0.2 grs. of it were 

 added per 1. of the water-current, then a trace of KNO" might 

 still be demonstrated in the rotting-water. Accumulation of G. pec- 

 tinovorum and rotting proved complete in this case, so that, when 

 Mr. Plaisier, flax-merchant at Hendrik Ido Ambacht, came to judge 

 of our rotted flax-samples, he classified our saltpeter-flax as "first 

 rate". But it is clear that the presence of saltpeter is not necessary. 



In fact, the accumulation of bacteria in the said experiment reposes, 

 besides on the slight but necessary aeration, on the circumstance that 

 by the water-current in the first 24 hours, such a complete extraction 

 of the flax is attained, that all soluble nitrogen compounds are 

 nearly completely expelled from it, and only the not easily soluble 

 protoplasmatic proteid remains in the flax-cells, which substance, 

 together with the still present carbohydrates and the pectose, prove 

 to be the very nutriment for G. pectinovorum and, moreover, the 

 food required to give rise to the secretion of pectosinase, hence, to 

 the rotting-process. If the extraction has not taken place and the 



