"BETTING" OF FLAX AND HEMP. 197 



119. The So-called "Retting" of Flax and Hemp. 



The present forms the most fitting occasion for making a few 

 explanatory remarks on this matter. -As is well known, it is the 

 bast fibre of these plants that is referred to when hemp or flax is 

 spoken of in the textile industry. In order to lay these fibres 

 bare and obtain them in a pure state, it is necessary to dissolve 

 the intermediate intercellular substance (the so-called central 

 lamellae) which consists, not of Pectose, as stated by J. Kolb, 

 but (according to the researches of Mangin) of calcium pectate. 

 This can be effected by chemical means, by a (patented) process 

 which Baur successfully introduced into Silesia on a large scale 

 in 1882, and which consists mainly in treating the plants with 

 very dilute sulphuric acid, and then neutralising the adherent acid 

 by a weak alkali bath. The solution of the cementing calcium 

 pectate can, however, be brought about by a fermentation, known 

 as "retting," that has been practised from remote ages without 

 any special knowledge of the more delicate processes involved. 

 According as the moisture necessary for this fermentation (or for 

 the development of the fission fungus effecting the same) is im- 

 parted to the rippled stalks by means of dew, sprinkling them 

 with water, or by immersion, the process is known as dew-retting, 

 water-retting, or, finally, mixed retting. 



With reference to the bacterial species taking an active part 

 in this process, VAN TIEGHEM (VI.) in 1879 expressed the opinion 

 that they should be assigned to his Bacillus amylobacter, which 

 he, as already mentioned, also regarded as the cause of cellulose 

 fermentation. The inaccuracy of this view is evident, since, if the 

 retting (Fr. rouissage, Ger. rosten) of the flax were mainly a process 

 of cellulose fermentation, there would not be much of the fibre 

 (which chiefly consists of cellulose) left. It was V. Fribes, who 

 working under the directions of S. WINOGRADSKY (I.) in 1895 

 clearly proved the true state of the case and made known the 

 active agent of this pectin fermentation. This organism is a 

 fairly large-celled species, occurring in the form of rods, which, 

 when young, have a length of 10-15 /x with a breadth of 0.8 /A, 

 but subsequently become broader ( i ju,), and swell up to a thickness 

 of 2 /u, at the one end (tadpole shape), where a long endospore 

 (1.2 x 1.8 /ut) is developed. This (anaerobic) bacillus will not grow 

 on gelatin, but when supplied with nitrogenous food in the form 

 of peptone will ferment glucose, saccharose, lactose, and starch, 

 leaving these, however, untouched when the peptone is replaced 

 by ammonia salts. On the other hand, even in this latter case, 

 any pectin bodies that may be present, i.e. pectin and pectic acid, 

 are fermented, and that, too, even more readily than the carbo- 

 hydrates already mentioned. The organism, however, has no 

 action on cellulose and gum-arabic. When clean portions of 

 plants, previously washed, first with acidified, and then with faintly 



