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. Storm er 1 ) 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- 
tensely red, showing the presence of pectin substance ; but, on the retted stem, 
the middle lamella of fibers showed only the hadromal reaction, indicating 
the destruction of pectin substance during the retting process. 
In our microscopical study we used the section of the stem 5-10 u in 
thickness, prepared either by the celloidin imbedding or the common paraffin 
i imbedding. 
For the celloidin imbedding, we must first prepare water free objects. 
To attain this object, the sample was treated first in dilute alcohol, then in 
strong alcohol and lastly in absolute alcohol. Then ,tlie objects were kept in 
a mixture of the same volume of alcohol and ether from (i-10 hours and then 
in the dilute celloidin solution, containing 2 grams of celloidin in 109 c.c. of 
the mixed solution ; then in the ^double' strong solution of celloidin from 2-3 
days and before the paraffin imbedding, the objects were kept in bergamot oil 
from 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 
1) — K . Stürmer. — Über die Wasserröste des Flaches.— Centr. bl. f. Agr. chem. (1905) p. 841. 
Centr. bl. f. Bakt. JT Abt. Bd. I (1904) p. 351. 
