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Gluten-casein .... .... .... .... .... .... 438

Gluten-fibrin .... .... .... .... .... *. 441

Maize-fibrin .... .... .... .... .... .... .... 441

Wlicat-mucedin .... .... .... .... .... .... 443

Rye-mucedin.... .... .... .... 444

Plant-gelatin .... .... .... .... .... .... 445

Appendix to Proteides of Wheat.

Gluten .... .... .... .... .... .... .... 447

Plant-fibrin .... .... .... .... .... .... 451

Phytocoll .... .... .... .... .... .... 452

Goemin .... ...; .... .... .... .... 452

Emulsin, or Synaptase .... .... .... .... .... 452

Diastase.... .... .... .... .... .... 455

Cerealin.... .... .... .... .... .... .... 456

Baregin .... .... .... .... .... .... .... 457

Yeast . 458



ADDENDA.

Paralbumin .... .... .... .... 464

Mucin from the Submaxillary Gland .... .... .... .... 466

Nuclein ... 467



COMPOUNDS CONTAINING 48 ATOMS OF CARBON.



Primary Nucleus C 48 H 33 ; Oxygen-nucleus

Sylvinolic Acid.



R. MALY. Wien. Acad. Ber. 44, 121; Krit. Zeitschr. 5, 47; J. pr.
Chem. 86, 111; Chem. Centr. 1862, 76; Repert. Chim. pure 4, 443;
Jahresber. 1861, 389.

Formation and Preparation. When hydrochloric acid gas is passed
into an alcoholic solution of abietic acid, the liquid becomes hot, and
assumes a brown colour, and, after cooling, deposits sylvic acid (xvii,
318), the brown filtrate from which yields sylvinolic acid in white
flocks, on addition of water.



C 88 H 64()io + 2HO = C^H^O 4 + C 48 E 36 O 8 ? (Kr.)

Properties. White amorphous powder, melting at 130 with decom-
position. Has an acid reaction.

Maly.

a. b. mean.

48 C ........ 288 .... 74-23 50 C ........ 300 .... 75*00 .... 74*55

36 H ........ 36 .... 9-28 36 H ........ 36 .... 9'00 .... 9'24

8O ....... 64 .... 16-49 8O ........ 64 .... 16'00 .... 16-21

C48 H 36 O 8.... 388 .... 100-00 C 50 H 36 O 8 .... 400 .... lOO'OO .... 100-00

Maly gives the formula b, but the formation of sylvinolic acid from abietic acid
seems to support the formula with 48 atoms of carbon.

Sylvinolic acid is insoluble in water. It is bibasic, and forms
neutral salts having the formula C^WO 8 .

Potash and Soda salts. Amorphous masses, soluble in alcohol, and
forming opalescent liquids in water.

Lime-salt. Obtained by precipitating an alcoholic solution of the
acid with alcoholic chloride of calcium and ammonia. Bulky flocks,
slightly soluble in alcohol.

Flocks. Maly.

C 48H3'O 6 ............ 370 ............ 86-85

2CaO ................ 56 ............ 13-15 ............ 10'24

C 48 H 34 Ca 2 O 8 .... 426 ............ lOO'OO

Silver-salt. Nitrate of silver throws down from the alcoholic acid
a white powder, which reddens on exposure to light, and dissolves
easily in ammonia- water, and with difficulty in alcohol.

VOL. XVIII. B



PRIMARY NUCLEUS C^H 39 ; OXYGEN-NUCLEUS C 48 EO 2 .

Maly.



G ........... . 370 ............ 61-46

2AgO ............ 232 ............ 38-54 ............ 37'04

C 48 H 34 Ag 2 O 8 _. 602 ........ 100-00

Sylvinolic acid dissolves easily in alcohol and in ether, and is left
behind in the form of a pitch on evaporating the solution.

Conjugated Compounds of Sylvinolic Acid.

1. Summary of the Constituents of the Pine resins.

The resinous sap which exudes from various species of conifers,
contains a volatile oil (xiv, 240) and one or more non-volatile con-
stituents, which consequently are found in turpentine, as well as in
the colophony or resin obtained by distilling turpentine with water and
melting the residual mass.

a. According to Unverdorben, colophony is to be regarded as impure
(amorphous) pinic acid. Turpentine, French colophony, and the resin
of Pinus sylvestris, contain also (crystallisable) sylvic acid, together
with smaller portions of other resins. Trommsdorff, Rose, and Liebig
likewise distinguish pinic and sylvic acids as two different acids.

fc. According to Laurent, the turpentine of Pinus maritima, as well
as the other species of pine, contains (crystallisable) pimaric acid,
which is converted on standing into the isomeric pinic acid (formerly
described as amorphous pimaric acid), and by distillation into the like-
wise isomeric sylvic acid (formerly distinguished as pyromaric acid).
Strecker (Ann. Pharm. 68, 338) regards sylvic, pimaric, and pyromaric
acids as identical, whilst according to Sievert, sylvic and pimaric acids
are different ; the latter, however, volatilises unaltered, so that Sievert
regards Laurent's pyromaric acid as pimaric acid.

c. According to Maly, whose view is here regarded as the soundest,
colophony or pinic acid is the anhydride of abietic acid, and suscep-
tible of conversion into (crystallised) abietic acid by absorption of
water. The salts of pinic acid are formed from abietic acid, by the
absorption of water. The sylvic acid of Unverdorben is also abietic
acid ; but not that of Sievert, who decomposed abietic acid by the
action of sulphuric acid, and examined the body thus formed as sylvic
acid, C 40 H 30 4 (xvii, 318). If the latter part of Maly's view is well
founded, Trommsdorff, Rose, and Liebig must have examined sylvic
acid, whilst it is not clear from the statements of Unverdorben and
Sievert, whether they refer to the acid prepared with sulphuric acid, or
to that obtained by crystallisation (Kr). Maly is inclined to regard
Laurent's pimaric acid also as abietic acid.



2. Abietic Acid.



MALY. Wien. ATcad. Ber. 44, 121 ; Krit. Zeitschr. 5, 47 ; J. pr. Chem.
86, 111; Chem. Centr. 1862, 73; Rep. Chim. pure, 4, 443; Kopp's
Jahresber. 1861, 389. Ann. Pharm. 129, 94; J. pr. Chem. 92, 1 ;



ABIETIC ACID. 3

Chan. Centr. 1864, 508 ; Krit. Zeitschr. 7, 441 ; Kopp's Jahresb. 1863,
402. Ann. Pharm. 132, 249; Kopp's Jahresb. 1864, 408. J. pr.
Chem. 96, 145; Chem. Centr. 1865, 1160; Kopp's Jahresb. 1865,
402.

See other researches under sylvic acid (xvii, 318) . Abietinsdure (Maly) to be
distinguished from the abietinic acid of Caillot.

Source. As abietic anhydride it forms, together with volatile oil
the chief constituent of the resin of Pinus Abies, P. Larix, and pro-
bably of other pines and firs.

Preparation. Powdered colophony is digested for a week with
70 per cent, alcohol, whereby it is converted into a granular mass ; the
liquid is separated ; and the residue is dissolved in alcohol of 90 to
92 per cent., then filtered, and completely precipitated by mixing the
solution with hot water. After pouring away the liquid, the brown
resinous cake is converted, on standing for 1 to 3 weeks, into a
crystalline mass, enclosing in its interstices a brown soft resin. The
latter body is removed by cold alcohol, and the crystals are pressed
and purified by crystallisation from hot alcohol. In this way crystals
are obtained amounting to 80 p. c. of the colophony employed (Maly).

Properties. Irregular, transparent, pointed crystals grown together
by their broader ends, or white, pointed, oval laminae (Maly). Doubly
oblique prismatic ? There are five faces (fig. 70) ; u' before and behind,
t before and behind to the left, and p. Angle t behind : u' behind =
47 ; t before : u before = 131 30' ; p : u 1 = 69 ; t behind : p = 104
(by calculation 104 35'); t before :p = 133 30' (v. Lang, J. pr. Chem.
96, 162). When heated to above 100 for some time, it cakes together
slightly. It begins to melt at 129, and melts completely at 144 with-
out losing weight. Has an acid reaction. It is eliminated by the
kidneys unaltered.



88 C ..


Crystals.
528


78-57


78-63


Maly.
mean.


78-54


(Kraut.)
78-37


64 H ..
10 O


64
80 ....


9-52
11-91


9-80
11-57





9-65
11-81


9-68
11-95

















C8SH64Q10 .... 672 100-00 100-00 lOO'OO lOO'OO

TT Strecker (Ann. Pharm. 150, 131; Zeitschr f. Chem. [2], 6, 381) denies the
existence of Maly's abietic acid, and regards the formula C^H^O 10 as founded on
incorrect analyses. He points out that the so-called abietic acid is prepared from
the same material, and in the same manner, as the sylvic acid of Unverdorben,
Trommsdorff, Siewert, and others (xvii, 318), Trommsdorff and Siewert in par-
ticular, not having used sulphuric acid in the preparation, by which, according to
Maly, abietic acid undergoes a transformation ; moreover, that the properties of
abietic acid, as described by Maly, exhibit a general agreement with those of sylvic
acid, excepting in the melting point, which has been stated by various authors at
temperatures ranging between 129 and 162 ; Duvernoy found 129 ; Maly's own
statements, made at different times, vary between 129 and 165. For these reasons
Strecker regards abietic acid as identical with sylvic acid, and as having the com-
position C^H^O 4 . The same view is held by Duvernoy (Ann. Pharm. 148, 143 ;
Zeitschr f. Chem. [2], 5, 303). See on the contrary Maly (Ann. Pharm. 149, 244;
Zeitschr f. Chem. [2], 5, 304) Tf.

B 2



4 PRIMARY NUCLEUS C^H? 8 ; OXYGEN-NUCLEUS

Decomposition. 1. On passing hydrochloric acid gas into alcoholic
abietic acid, sjlvic (xvii, 318,) and sylvinolic acids are formed:



+ 2HO = C 48 H 35 O 8 + CWH^O 4 ? (Kr.)

"Wlien abietic acid is added to boiling alcoholic hydrochloric acid, and distilled,
a small quantity of oily drops, probably of an ethyl- compound, passes over.
2. Abietic acid is but little altered in appearance by dry chlorine, but
it evolves hydrochloric acid gas, and increases about 14*13 p. c. in
weight.

The product is Maly's dichlor abietic acid, C^CPH^O 5 , in accordance with his
older formula for abietic acid, C^IP-'O 5 . In the formation of this body, however,
100 parts of abietic acid must have taken up 20 - 53 parts, and not as Maly calculates,
13'4 parts, of chlorine. The statement that this acid contains 16'92 p. c. of chlorine
(calc. 17-53 p. c. Cl) is in favour of Maly's formula C^CPH^O 5 , or C^CPH^O 10 ;
but this formula is inconsistent with the fact that the soda-salt of the acid contains
10-45 p. c. of soda, whilst by calculation it should contain only 7*26 p. c. (Kr.).
" Dichlorabietic acid " forms a whitish-yellow mass of acid reaction, melting at 124,
with liberation of suffocating vapours. It dissolves less freely than abietic acid in
hot dilute caustic soda, and is precipitated unaltered by acids. It is less soluble
than abietic acid in alcohol, easily soluble in ether. Its soda-salt, obtained by add-
ing carbonate of soda to a hot alcoholic solution of the acid and evaporating, forms
an alkaline brittle resin.

3, Abietic acid dissolves easily when triturated with oil of vitriol,
forming a reddish-brown solution, from which it is at first precipitated
by water unchanged. When the solution is slightly warmed, or
allowed to stand for 24 hours, it evolves sulphurous acid, after
which water throws down a reddish precipitate containing sulphur,
which dries up to a whitish-yellow mass over oil of vitriol. This body
is decomposed at the temperature of 80 in the moist state, with liberation
of sulphuric acid, and even when dry it turns soft and blackens below 100. It
has an acid reaction ; forms with alkalis uncrystallisable compounds, and with baryta a
compound which is insoluble in alcohol, and contains sylvic acid, together with about
an equal number of atoms of sulphuric acid. It dissolves slightly in alcohol, and
very easily in ether-alcohol, forming a purplish-violet solution, which turns brown
on standing - On mixing a hot alcoholic solution of abietic acid with
sulphuric acid, sylvic acid is produced. No sugar is formed, even after
long standing.

4. When triturated with pentachloride of phosphorus, abietic acid
turns warm and brown and becomes fluid ; the product yields on distil-
lation, hydrochloric and chlorophosphoric acids in succession, and,
lastly, at 295 to 350, and still higher temperatures, a volatile oil,
whilst charcoal remains behind (Maly).

The volatile oil, Maly's abietone, forms when rectified a wine-yellow
fluorescent liquid, of faint aromatic odour, free from chlorine, and when
rectified over sodium, free from oxygen. It solidifies to an amorphous
mass in the cold. When it is submitted to fractional distillation and
collected in four portions, the separate portions, the first of which
distils at 295 to 303, have the composition given below, for which
Maly gives the accompanying formulae. Bromalrietone, obtained by
dissolving the first portion in ether and adding bromine, is dark-
brown, not decolorised by potash, and contains 23*6 to 27*2 p. c. of
bromine.

a. Maly. b. Maly.

88 C ........ 89-80 ........ 89-84 88 C .... 90'41 ........ 90-24

60 H ....... 10-20 ........ 10-21 56 H .... 9'59 ........ 9'50

... 100-00 . 100-05 C^fl 56 ... 100-00 . 9974



ABIETIC ACID.



88 C


c.

90'72


Maly.
.. 90*40


88 C


d.
91*35


Maly.
91'12


54 H


9-28


9-19


50 H


8-65


8'79















100-00 99-59 C 88 !! 50 .... 100-00 99'91

5. Abietic acid is converted by the action of sodium-amalgam into
hydrabietic acid. 6. When fused with hydrate of potash it yields pro-
pionic, but no protocatechuic acid (Maly).

Combinations. Abietic acid is Ubasic, and forms (rarely) acid and
(generally) neutral salts.

Ammonia-salt. Abietic acid dissolves easily in alcoholic ammonia.
In aqueous ammonia the crystals swell up, turn cloudy, and dissolve,
at first to an opalescent liquid, which becomes clear on warming- or on
addition of more ammonia. The solution solidifies to a clear stiff jelly
on cooling.

Abietic acid dissolves in warm potash and soda-ley, without forming
crystallisable compounds. These solutions, and that obtained by
adding carbonate of soda to the alcoholic acid, dry up to yellow amor-
phous brittle masses, soluble in alcohol. The acid is not soluble in
aqueous carbonate of potash.

Baryta-salt. Chloride of barium throws down from the aqueous
potash-salt dense flocks, which dissolve more easily in alcohol than in
water.

Maly.

C 84 H 62Oio 670 83-02

2Ba 137 16-98 17'11

C 88 H 62 Ba 2 10 .... 807 lOO'OO

Lime-salt. Formed by mixing an alcoholic solution of the am-
monia-salt with alcoholic chloride of calcium. A portion of the com-
pound is precipitated at once, and the greater part on pouring the
filtrate into a large quantity of water. White powder, which does
not lose weight at 100. Dissolves easily in alcohol, slightly in
water.

Maly.

C 88 H 62Oio 670 94-37

2 Ca 40 5-63 5'80

CH 62 Ca 2 O 10 .... 710 100-00

An acid lime-salt cannot be * obtained in the same way as the cor-
responding magnesia-salt (Maly).

Magnesia-salt. A. Neutral. Aqueous chloride of magnesium
forms with the potash-salt, flocks which change to a dense sandy
deposit. The salt dissolves with difficulty in water, and easily in

alcohol.

Maly.
Over oil of vitriol. mean.

C^H^O 10 670 96-53

2 Mg 24 3-47 3'53

0H 62 Mg ! O 10 .... 694 10010



6 PRIMARY NUCLEUS C^H 33 ; OXYGEN-NUCLEUS CH*0.

B. Acid. Obtained by boiling alcoholic abietic acid with carbonate
of magnesia as long as a test-portion of the liquid is turned milky by
water, and until a flocculent precipitate is formed ;. filtering into a large
quantity of water ; and collecting the quickly deposited flocks. Light,
white mass, resembling magnesia. Becomes electric when rubbed,
and hardens at 100, without losing weight. Dissolves easily in
alcohol, and is precipitated from the solution by water,

Maly. (Kraut.)

C88H63Q10 ........ 671 ............ 9825

Mg .................... 12 ............ 175 ............ 1-56 ............ 1-62

C 88 H 63MgO 10 .... 683 ............ 100-00

Alumina- salt. White flocks, slightly soluble in water and in
alcohol, easily soluble in ether and in bisulphide of carbon.

Zinc-salt. Formed from the potash-salt and sulphate of zinc.
White flocks, nearly insoluble in water, slightly soluble in alcohol, and
freely in ether,

Maly.

Over oil of vitriol. mean.

C^H^O 10 ............ 670 ............ 91-15

2 Zn .................... 65 ............ 8-85 ............ 9'13

CSWZnSQ 10 .... 735 ............ 100-00

The potash-salt throws down from nitrate of cobalt a peach-blossom
coloured, and from mercurous nitrate, a white precipitate, both un-
changed by boiling.

Copper-salt. A solution of abietic acid in ether or bisulphide of
carbon, takes up a large quantity of oxide or carbonate of copper.
Sulphate of copper throws down from the potash-salt of abietic acid
pale-green flocks, slightly soluble in water and alcohol, easily soluble
in bisulphide of carbon and ether, with splendid green colour.

Maly.
C 88 H 62oio ............ 670 ............ 91-36

2 Cu .................... 63-6 ............ 8-64 ............ 8'67

C8SH<52Cu 2 O 10 ........ 733-6 ........... 100-00

Silver-salt. Alcoholic nitrate of silver throws down from a warm
alcoholic solution of abietic acid, on addition of a drop of ammonia-
water, a white pulverulent precipitate, slightly soluble in alcohol
and very easily soluble in ammonia- water and ether. This salt alone, and
no acid salt, is formed also when an ethereal solution of the silver-salt is mixed with
excess of abietic acid and precipitated by ammonia, or when the acid magnesia-salt
is precipitated by niti-ate of silver.

Maly.
88 C .................... 528 ............ 59-61 ............ 59'5L

62 H ..... _ ............ 62 ............ 6-99 ............ 7-39

10 .................... 80 ............ 9-03 ............ 9-07

2Ag ................ 216 ............ 24-37 ............ 24-03



Five other salts contained 2571 to 26'32 p. c. of oxide of silver (theory requires
26-17 p. c. AgO).



ABIETIN. 7

Abietic acid is soluble in bisulphide of carbon, wood-spirit, chloroform,
ether, and benzene (Maly). It does not combine with urea or aniline
(Maly).

3. Abietate of Ethyl.

C 98 H 72 10 _ 2C 4 H 5 0,C 88 H 62 8 .

R. MALY. J. pr. Chem. 96, 145.

Freshly precipitated abietate of silver is added, in small portions, to
iodide of ethyl previously diluted with ether, whereupon the mixture
becomes warm and iodide of silver separates. After standing for
24 hours, the liquid is filtered, and the filtrate evaporated over the
water-bath. The product is purified by dissolving it in ether-alcohol,
precipitating with water, taking up the oily drops which separate

with ether, and evaporating This body is not formed by passing hydrochloric

acid gas into alcoholic abietic acid, and is only sparingly formed by distilling an
alcoholic solution of abietic acid with oil of vitriol.

Abietate of ethyl forms a yellowish, clear, somewhat soft mass, of
a syrupy consistence at 100 and having a resinous ethereal odour.
It is decomposed by distillation, with elimination of water. It is
insoluble in water, but sparingly soluble in alcohol, easily in ether and
ether-alcohol.

Maly.
mean.



96 C


576


78-15


78-16


73 H


73


9-90


9-92


11 O .


88 .


11-95


11-92











2C 4 H 5 O,C 88 H 62 O 8 + HO .... 737 ........... lOO'OO ........... lOO'OO

The formula 2C 4 H 5 O, C^H^O 8 requires 79'1 p, c. C., 9'69 H.

4. Abietin.

? C 106 H 76 16 = SC'H'O^C 88 !! 6 ^ 7 .
R. MALY. J. pr. Chem. 96, 146.

A mixture of concentrated alcoholic abietic acid and glycerin, after
standing for 14 days in the cold, deposits small white crystals, which
after washing with water melt at 125, and dissolve in ether and alcohol,
but cannot be recovered from the solutions in an unchanged state.
The crystals are formed from 3 atoms of glycerin and 1 atom of abietic
acid, with elimination of 12 atoms of water :



3C G H 8 O 6 = 3C 6 H 5 3 ,C 88 H 61 Q7 + 12HO.

Maly.
106 C ... , 636 ............ 75-71 ............ 75-38

76 H ............. 76 ............ 9-04 ............ 9'23

16 O ............................ 128 ............ 15-25 ............ 15-39

........ 840 ............ 100*00 ............ lOO'OO



8 PRIMARY NUCLEUS C^H 38 ; OXYGEN-NUCLEUS

5. Abietic Anhydride.

C 88 H e2 = C 48 H 38 6 ,C 40 H 29 3 .
MALT. Ann. Pharm. 132, 249 ; J. pr. Chem. 96, 140.

Abietic acid does not undergo any alteration at 100, and even at
higher temperatures does not give off water until it begins to be coloured
and decomposed. Neither does it yield an anhydride when melted in a
stream of carbonic acid and more strongly heated. But the forma-
tion of abietic acid from pine and larch resins, as well as from colo-
phony, is the result of the absorption of water, so that these bodies
must be regarded e as the anhydride of abietic acid, or as mixtures
containing it, as the following experiments show :

a. Colophony dried over oil of vitriol is dissolved in alcohol ; and
water is added to the solution till turbidity is produced ; then after the
formation of a mass of crystals of abietic acid, the whole is evaporated,
and the residue is again dried over oil of vitriol, and lastly in the water-
bath. In this way 96*5 parts of colophony take up 3'5 parts of water,
corresponding to the formula C^H^O 8 + 2HO (calc. 3-82 parts HO).

b. A solution of colophony in absolute alcohol deposits no crystals,
even after standing for months, whereas a solution in alcohol of 70 p. c.
deposits as much as 80 p. c. of the amount dissolved in 8 days. simi-
larly the resinous drops which exude from pine trunks retain their transparency,
after becoming hard from loss of volatile oil, and turn milky and crystalline only in
wet weather.

c. When the resin collected from pines or larches is freed from
volatile oil over the water-bath, there remains an amorphous yellow
residue, which softens between 90 and 100, is of a syrupy con-
sistence at 100, and dissolves easily in alcohol, ether, and chloroform.
This body has the composition of abietic anhydride.

Maly.
Pine and Larch resins.

88 C 528 80-73 80'23

62 H 62 9-48 9'87

80 64 9-79 9-90

C 88 H 62 O 8 ... ( 654 . WO-OO . 100-00



6 Hydrabietic Acid.



MALY. J. pr. Chem. 96, 149.

^ Sodium-amalgam is added to a warm alcoholic solution of abietic
acid so long as each fresh addition continues to produce a perceptible
action, and the resulting soda-salt is allowed to crystallise in the cold.
From the aqueous solution of this salt, neutral acetate of lead throws
down hydrabietate of lead, which is decomposed under alcohol by



COLOPHONY AND PINIC ACID. 9

hydrosulphuric acid. The solution, freed from sulphide of lead by
filtration, yields crystals of hydrabietic acid on spontaneous evapo-
ration.

White fatty laminae, melting partially at 140 and completely at
160. Burns on platinum foil, evolving resinous vapours, and leaving
no residue.

Maly.
mean.

88 C 528 78-10 77'97

68 H 68 10-05 10-28

10 80 11-85 11-75

C 88H'O 10 6 ? 6 100-00 100-00

Hydrabietic acid is insoluble in water. It is Ubasic, and forms
neutral salts, represented by the formula, C^H^MH) 10 .

Soda-salt. Long, silky needles, which effloresce rapidly in the air,
and lose the whole of their water at 100.

Maly.

C88H66Q10 674 87-08

2Na 46 5-94 6'18

6 HO 54 6-98 6'62

C88H 66 JSTa 2 10 + 6HO .... 774 100-00

Lime-salt. Precipitated by chloride of calcium from the ammonia-
salt, in white flocks soluble in alcohol.

The aqueous soda-salt produces white precipitates with neutral
acetate of lead, mercurous nitrate, and nitrate of silver ; it does not preci-
pitate mercuric chloride.

Hydrabietic acid dissolves easily in alcohol and ether.



Appendix to Abietic Acid,

1. Colophony and Pinic Acid.

The colophony or resin, obtained by distilling turpentine with water
and melting the residual mass, is to be regarded, according to Unver-
dorben, as impure pinic acid, or according to Maly, as abietic anhydride.
Pinic acid occurs also in white resin and in turpentine.

Unverdorben's pinic acid is obtained by distilling Venice turpentine
with water, so that the oil of turpentine passes over ; dissolving the
residue in 65 p. c. alcohol ; precipitating the solution with alcoholic
acetate of copper; washing the precipitate with absolute alcohol;
dissolving it in alcohol containing hydrochloric acid, and mixing the
solution with |th of its volume of water. It forms a colourless trans-
parent mass, hard and brittle in the cold, but elastic when warmed, and
melting like colophony. It is inodorous, and has a very faintly bitter
taste (Unverdorben). Sp. gr. of colophony = 1-0727 (Brisson), 1-08
(Thomson). Pinic acid is obtained by the spontaneous evaporation of
its ethereal solutions in amorphous granules containing 77-66 p. c. C.,
9*73 H., and 12-61 0., and is consequently isomeric with sylvic acid
(Laurent, Ann. Chim. Phys. 65, 324).

According to Unverdorben, colophony (as also the resin of Pinus



10 PRIMARY NUCLEUS C 4 *H. ; OXYGEN-NUCLEUS

sylvestris) contains two other resins, differing- from the preceding:
a. A resin soluble in rock-oil and oil of turpentine, obtained by digesting



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