FLAX-STEM ANATOMY IN RELATION TO RETTING. 17 
the wooden core entirely free from any fibers. The wooden core 
is then broken 6 to 9 inches above the first break (fig. 15), the 
worker being careful not to leave any jagged pieces of wood that 
would catch on the fibers when the test is made. In the third 
step one hand grasps the stem above the second break and the 
other pulls on the exposed lower end of the wooden core (fig. 16). 
In a positive loose-core test (fig. 17) the wooden core slips out 
from the cortex with- 
out any clinging on 
the part of the fibers. 
The cortex or fibrous 
cone pulls away from 
the wooden core as a 
single unit, and there- 
fore the loose -core 
test does not give any 
idea as to the fine- 
ness of division of 
the fibers. For the 
same reason it does 
not give any indica- 
tion as to the degree 
of disintegration of 
the epidermis, for 
even though the cuti- 
cle were already-sepa- 
rated and ready to 
drop away from the 
fibers at the shght- 
est dislodement at the 
time the loose - core 
test is made, it re- 
mains clinging to the 
fibers in an undis- 
turbed condition as 
the core is withdrawn. 
It is therefore neces- 
sary to devise a test 
in which the cortex 
is not handled as a 
single unit and in 
Fic. 12.—Retting flax, showing the persistence of the 
leaf scars. The process of retting has here reached 
one of the last stages. The cortex has separated 
from the wooden core, but is still almost intact. The 
structure of the epidermis shown as part of the un- 
derlying tissue has been destroyed. Explanation: 
which the stages of 
retting in the differ- 
ent parts of the cortex 
b = Fiber branches, e = epidermis, f = fiber bundles, 
l= ieaf scar, p = point of attachment. Note how the 
fiber branches cling to the leaf scar at points of at- 
tachment. 
may be observed. 
A difficulty is experienced in testing wet flax stems for completion 
of retting regardless of the method used; when the stems are with- 
drawn, one at a time, from the retting tanks which are tightly 
packed with flax straw, all or part of the cortex may be rubbed off 
by contact with the adjacent stems. The stem, being in the nature 
of a wedge, slips out more readily if it is withdrawn from the butt 
end of the bundle. This precaution is not sufficient to prevent 
injury to the cortex from contact with the other stems. The diffi- 
