Scientific American Supplement, No. 443, June 28, 1884 | Page 8

small pieces, and
placed them in a large glass beaker, then nearly filled it with distilled
water, and heated to about 80° C., keeping the decoction at this
temperature for about half an hour, I occasionally stirred with a glass
rod, and then allowed it to cool, and filtered. This filtrate was then
evaporated nearly to dryness, when a small quantity of six-sided prisms
crystallized out, which subsequently were found to be the hydrate of
phenol (C_{6}H_{5}HO)_{2}H_{2}O. Its melting point was found to
be 17.2° C. Further, the crystals already referred to were dissolved in
ether, and then allowed to evaporate, when long colorless needles were
obtained, which, on being placed in a dry test tube and the tube placed
in a water bath kept at 42° C., were found to melt; and on making a
careful combustion analysis of these crystals, the following
composition was obtained:
Carbon 76.6 Hydrogen 6.4 Oxygen 17.0 ----- 100.0
This gives C_{6}H_{6}O, which is the formula for phenol.
On dissolving some of these crystals in water (excess) and adding ferric
chloride, a beautiful violet color was imparted to the solution. To
another aqueous solution of the crystals was added bromine water, and
a white precipitate was obtained, consisting of tribromophenol. An
aqueous solution of the crystals immediately coagulated albumen.
All these reactions show that the phenol occurs in the free state in the
cones of this plant. In the same manner I treated the acicular leaves, and
portions of the stem separately, both being previously cut up into small
pieces, and from both I obtained phenol.
I have ascertained the relative amount of phenol in each part of the

plant operated upon; by heating the stem with water at 80° C., and
filtering, and repeating this operation until the aqueous filtrate gave no
violet color with ferric chloride and no white precipitate with bromine
water.
I found various quantities according to the age of the stem. The older
portions yielding as much as 0.1021 per cent, while the young portions
only gave 0.0654 per cent. The leaves yielding according to their age,
0.0936 and 0.0315 per cent.; and the cones also gave varying amounts,
according to their maturity, the amounts varying between 0.0774 and
0.0293.
Two methods were used in the quantitative estimation of the amount of
phenol. The first was the new volumetric method of M. Chandelon
(Bulletin de la Societe Chemique de Paris, July 20, 1882; and
_Deutsch-Americanishe Apotheker Zeitung_, vol. iii., No. 12,
September 1, 1882), which I have found to be very satisfactory. The
process depends on the precipitation of phenol by a dilute aqueous
solution of bromine as tribromophenol. The second method was to
extract, as already staled, a known weight of each part of the plant with
water, until the last extract gives no violet color with ferric chloride,
and no white precipitate with the bromine test (which is capable of
detecting in a solution the 1/60000 part of phenol). The aqueous extract
is at this point evaporated, then ether is added, and finally the ethereal
solution is allowed to evaporate. The residue (phenol) is weighed
directly, and from this the percentage can be ascertained. By this
method of extraction, the oil of turpentine, resins, etc., contained in
Pinus sylvestris do not pass into solution, because they are insoluble in
water, even when boiling; what passes into solution besides phenol is a
little tannin, which is practically insoluble in ether.
From this investigation it will be seen that phenol exists in various
proportions in the free state in the leaves, stem, and cones of Pinus
sylvestris, and as this compound is a product in the distillation of coal,
and as geologists have to a certain extent direct evidence that the flora
of the Carboniferous epoch was essentially crytogamous, the only
phænogamous plants which constituted any feature in "the coal forests"

being the coniferæ, and as coal is the fossil remains of that gigantic
flora which contained phenol, I think my discovery of phenol in the
coniferæ of the present day further supports, from a chemical point of
view, the views of geologists that the coniferæ existed so far back in
the world's history as the Carboniferous age.
I think this discovery also supports the theory that the origin of
petroleum in nature is produced by moderate heat on coal or similar
matter of a vegetable origin. For we know from the researches of
Freund and Pebal (_Ann. Chem. Pharm._, cxv. 19), that petroleum
contains phenol and its homologues, and as I have found this organic
compound in the coniferæ of to-day, it is probable that petroleum in
certain areas has been produced from the conifers and the flora
generally of some primæval forests. It is stated by numerous chemists
that "petroleum almost always contains solid paraffin" and similar
hydrocarbons. Professors