CnuvncH.—On the Chemistry of Phormium tenax. 263 
centage of sugar was deduced from the examination of the matters thus 
removed from the tissues of the leaves. The analysis of the solution thus 
prepared led to the following numbers, as representing the proportion of sugar 
in the leaves of the Phormium :— 
Caleulated as Cane Sugar. 
In the fresh leaves ев es “ii 5:45 per cent. 
In the dry leaves d 19:20 as 
It may be concluded that these numbers are rather too high, owing to the 
conversion of some of the gum and starch of the plant into sugar by means of 
the treatment to which the aqueous extract had been submitted. But though 
Dl per cent. of sugar is probably an extravagant estimate, I am inclined to 
think that it is not more than 1 per cent. in excess of the truth; so far, at 
least, as the richness of English grown leaves is concerned. 
D.—The Bitter Principle. 
A notion appears to prevail that the bitter principle of the Phormium 
tenax is a coloured substance: this is quite incorrect. Doubtless when an 
aqueous or alcoholic extract of the leaf is made, the bitter principle, thus 
dissolved out, is accompanied by colouring matters, but these matters merely 
accompany the true bitter principle. If reference be made to the report, 
p. xix., 1871, of the Flax Commissioners,* it will be seen that the bitter 
principle is therein spoken of as coloured—‘ purity of colour can only be 
obtained by thoroughly washing out the bitter principle from the plant.” 
Again, in the appendix to the above-named report, at page 84, Capt. Hutton 
states, “The bitter principle might perhaps be used as a dye or stain for 
wood,” etc. The mixed nature of the substances extracted from the plant by 
water, and the subsequent changes which some of the substances undergo in 
the presence of air and moisture, account for the mistake which I have pointed 
out. As I shall have again to refer to the colouring matters of Phormium in 
the next section, I will now merely describe the method by which the bitter 
principle was obtained in a state approaching purity. 
The selected leaves were cut into small pieces and then carefully dried. 
About a pound of the dry matter was then exhausted with boiling alcohol. 
The hot alcoholic extract (or rather extracts) was then filtered, some wax (see 
§ 1 B) being deposited on the filter during the passage of the liquid through 
it. The filtered liquid was then evaporated, first in a retort, then at 100° 
centigrade, and finally in vacuo. The residue corresponded to 19-6 per cent. 
of the dried leaves taken. It was, of course, free from starch and gum, but 
contained many other substances besides the bitter principle. In order to 
isolate this principle the following plan was adopted :—The last-described 
residue was boiled in abundance of water, and then the liquor was filtered, 
* App. to Journ. H. of R., 1871, G. No. 4. 
