ON FLAX, 129 
strongly acid extract, which was found to consist chiefly of a peculiar tannic 
acid, which strikes a deep green colour with the persalts of iron. This acid, 
which may provisionally be termed lino-tannic acid, was also obtained in white 
needle-shaped crystals, by adding neutral acetate of lead to the zthereal solu- 
tion of the plant, and decomposing the lead compound diffused in alcohol by 
sulphuretted hydrogen. The filtrate from the sulphuret of lead, which had 
an orange colour, when evaporated to dryness, afforded on treatment with 
zether, a solution from which, when the ether has spontaneously evaporated, 
crystals of the acid separated. The acid, though existing in minute quantity 
in the plant, has been detected both in the unsteeped and dressed flax, and 
possesses considerable interest in connexion with the technical preparation 
of the fibre, as its presence explains the discoloration which is frequently 
observed when the flax-straw has been steeped in water containing salts of 
iron. In addition to the lino-tannic acid, the straw of the flax plant was 
found to contain a considerable amount of malic acid, and also an acid yellow 
colouring substance of a resinous nature, which can be extracted by alcohol, 
and yields, with basic acetate of lead, a rich chrome-yellow-coloured preci- 
pitate, which, when suspended in alcohol and decomposed by sulphuretted 
hydrogen, and the sulphuret of lead removed, yields a straw-coloured liquid, 
from which, on evaporation, the resin is obtained in the form of a tenacious 
orange-brown extract, which is insoluble in zther, but dissolves readily in 
alcohol, and is precipitated from its solution in the form of a buff-coloured 
- mass, which is dissolved by alkalies, with the production of a rich orange- 
coloured solution. 
From the green plant, and also from the dressed fibre, water extracts a 
gelatinous substance which is thrown down as a bulky precipitate on the 
addition of alcohol. ‘This precipitate was found to consist of pectine with 
malate and sulphate of lime. In the unripe plant, and also in the stems, as 
pulled from the field in the usual state of maturity, when the seeds contained 
in the capsules have commenced to assume a brown colour, starch was dis- 
covered, and could readily be extracted by placing the stems in a powerful 
lever press, and moistening them with a small quantity of water. By allow- 
ing the expressed liquids to remain at rest, the starch subsides, and can be 
recognized by the microscope as consisting of extremely minute corpuscles, 
which assume a purple colour on the addition of a watery solution of iodine. 
When, however, the flax-straw is examined after it has remained exposed to 
the air for several days in the stook, the liquid obtained by subjecting it to 
pressure and washing with water was found to afford no indication of the 
_ presence of starch. In the dressed flax, no starch could be detected, but 
the presence of a considerable amount of grape-sugar was demonstrated. 
The discovery of grape-sugar in the fibre is in many respects exceedingly 
interesting, as it serves to afford an explanation of the statement frequently 
_ made by experienced steepers, that, by storing up the steeped flax as imper- 
fectly dried, by exposure to the air for some weeks before proceeding to re- 
move the adherent woody matters by mechanical means (by scutching), the 
_ Separation of the fibre is found to be greatly facilitated, and its qualities 
: improved. 
4 Examination of the Steeping Process. 
_- As stated in former communications to the Section, experiments, which 
‘were conducted by immersing flax in water, both at ordinary temperatures, 
and also in vats filled with water, heated and steadily maintained at from 
80° to 90° Fahr., have shown that in both cases the series of decompositions 
1 ed might be regarded as identical, and that the fermentation 
1857. K 
