STUDIES ON FLAX RETTING. 35 



with woody substances and that the middle lamella of fibers are therefore not 

 destroyed in the retting process, though the bast fibers are separated from 

 the parenchyma which are destroyed by micro-organisms. 



In 1904 D. Stormeri) made further investigations on this 

 point and ascertained that the portions which gave a wood reaction with 

 phloroglucin and hydrochloric acid or anilin sulphate are middle lamella of 

 the bast fiber cells and xylem portion, and that the bast fibers themselves and 

 - cell-walls of cortical parenchyma gave no color reaction. When the middle 

 lamella were treated with ruthenium red, they stained, like parenchyma, in- 



i presence of pectii 



le middle lamella of fibers showed only the hadromal reaction, indicating 

 le desctruction of pectin substance during the retting process. 



In our microscopical study we used the section of the stem 5-10 u in 

 lickness, prepared either by the celloidin imbedding or the common paraffin 

 nbedding. 



For the celloidin imbedding, we must first prepare water free objects, 

 'o attain this object, the sample was treated first in dilute alcohol, then in 

 trong alcohol and lastly in absolute alcohol. Then ,the objects were kept in 

 mixture of the same volume of alcohol and ether from 6-10 hours and then 

 a the dilute celloidin solution, containing 2 grams of celloidin in 100 c.c. of 

 he mixed solution ; then in the double' strong solution of celloidin from 2-3 

 lays and before the paraffin imbedding, the objects were kept in bergamot oil 

 rom 12-24 hours. After the treatment, the objects were imbedded in 

 paraffin according to the usual method. 



1. Anatomical Structure of Flax Stem. 



Before we go into the results of our observations upon the changes of 

 structure during retting, let us briefly describe the anatomical structure of the 



K . Stormer.— tfber die Wasserroste des Finches. -Centr. M. f. Agr. chem. (1905) p. 841. 

 Centr. bl. f. Bakt. IT Abt. Bd. f. (1904) p. 351. 



