STUDIES ON FLAX RETTING. 



15 



I. In case the water is not changed, the loss of weight in the total stem 

 is about 18-16* or about ±% less than that in the common water retting 



3. The loss of weight due to the extractive power of water is about 

 55-60* of total loss. 



4. The greater part of the loss takes place before the end of first period 

 of retting. 



2. Composition of Flax Stem and their 

 Changes in Retting. 



Investigations on the composition of flax and their changes involved in 

 retting are bat few. In 1854 Hodges D determined the chief constituents of 

 flax fiber and found 82.5% of cellulose, and 7.6% of sugar, gums and pection 

 compounds. Omelianski 2) reported in 1904, results of his investigations 

 concerning the amounts of pectin compounds and cellulose in the retted as well 

 as in the control flax stem. For the study of pectin compounds, he treated 5 

 grams of the stem with alcohol for half an hour, washed with water and the 

 residue was then extracted with 250 c. c. of 2% hydrochloric acid solution for 

 half an hour. To the extracts was added an equal volume of strong alcohol, to 

 precipitate the pectin compounds. In the extract obtained from the control 

 stem some precipitate of pectin compounds was formed but none in that from 

 retted stem. It is evident from his results that the pectin compounds suffer 

 decomposition in retting process. On the other hand, the amount of cellulose 

 seems to remain unchanged. In his determination of cellulose he took 3 grams 

 of sample and mixed with 500 c.c. of Schweitzer's reagent. After standing for 

 5 days it was filtered through glass wool filter and precipitated with dilute 

 hydrochloric acid. The precipitate was washed with water, dried and 

 weighed. From the control stem 0.6959 grams of cellulose was obtained, 

 while in the retted stem 0.6979 grams of cellulose was found. 



