August 20, 1870.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
155 
greenish-grey powder, which, when examined under the 
microscope, presents numerous crystals of carbonate of 
lime. The liber (endophloeum) is tough, and leaves 
fibrous pieces on being pounded. The dry bark is light 
and breaks easily across with a fibrous porous fracture. 
It scarcely possesses any smell, but has a pure strongly 
bitter taste, especially at its inner surface. The wood, 
as well as the leaves of this tree, are entirely devoid of 
bitterness. 
Seat of the Active Principle. —On examining a section 
of the fresh bark with an ordinary magnifying glass, the 
meshes between the interlacing fibres of the liber are 
seen filled up here and there with a reddish- or orange- 
yellow and somewhat glistening amorphous substance, 
which abounds within the inner part of the liber. Inter¬ 
mixed with it, and covering the whole of the fibrous 
texture of the mesophloeum, are seen shiny rhombic par¬ 
ticles of crystalline carbonate of lime. The yellow amor¬ 
phous substance is very soluble in water, and extremely 
bitter, and is the active principle of the bark in a state 
of combination. It is found in the largest proportion in 
the thick bark of old trees. The thinner bark of the top 
and branches is less valuable, for it contains a smaller 
amount of the active principle. 
Composition and Chemical Characteristics. —No 
complete analysis of the Ailanthus bark has as yet been 
made. My experiments, however, lead me to conclude 
the presence in it of an uncrystallizable bitter principle 
in combination with lime, carbonate of lime, salts of 
magnesia and alumina, uncrystallizable sugar, gum, a 
trace of volatile oil and lignin. The medicinal virtues 
of the bark depend entirely upon an azotized bitter prin¬ 
ciple possessing an acid nature, to which I propose to 
give the name of ‘ Ailanthic acid.’ It is to this that the 
bark owes its bitterness. 
A cold infusion of the bark, in the proportion of one 
ounce to twenty-four ounces of cold water, and allowed 
to macerate for twenty-four hours, was somewhat turbid, 
lemon-coloured, and very bitter. A strong decoction of 
it was turbid and highly bitter: when kept for some 
days, it slowly deposited a sediment, and the liquid be¬ 
came of a clear pale lemon-colour, and retained its 
bitterness. A tincture of the powdered bark, prepared 
with rectified spirit, was of a pale yellow colour and 
much less bitter than the decoction or infusion. The de¬ 
coction exhibited the following reactions :—Tincture of 
iodine or tincture of the sesquichloride of iron produced 
no change; oxalic acid or oxalate of ammonia caused 
a copious white precipitate (oxalate of lime), insoluble 
in acetic acid; alcohol produced muddiness (from the 
precipitation of gum) in a concentrated decoction; pro¬ 
tonitrate of mercury solution gave a copious white preci¬ 
pitate of a complex compound of the acid principle with 
mercury; solution of basic acetate of lead produced 
abundant white precipitate ; alkalies produced no change 
except removing its bitterness, which reappears on the 
addition of acids; alkaline carbonates and earths showed 
no such effect; acids produced no change; litmus-paper 
showed no signs of acidity (evidently showing that the 
acid principle was in combination with a base). 
Ailanthic Acid. —It was in the beginning of the year 
1867 that I first noticed the existence of this principle in 
the Ailanthus bark. Owing to its uncrystallizable nature 
and its comparative insolubility in other solvents than 
water, the difficulty of obtaining it in a pure state is 
such as to make its analysis still unsatisfactory. I leave 
to abler chemists its further examination. The following 
method gives the process of manufacturing this sub¬ 
stance :— 
Exhaust the powdered Ailanthus bark by repeatedly 
boiling it with water, collect and concentrate the decoc¬ 
tions. When cold, filter and add a sufficient quantity of 
a strong solution of oxalic acid to precipitate the lime. 
Add a sufficient quantity of strong solution of basic ace¬ 
tate of lead, which precipitates gum, extractive matter, 
colouring-matter, and excess of oxalic acid; filter. Con¬ 
centrate the clear liquor on a slow fire, remove it when 
cold into a proper vessel, and pass through it sulphuretted 
hydrogen gas so as to precipitate all the lead; boil, 
filter, and evaporate the clear liquid on a water-bath.* 
The proportion of ailanthic acid contained in the bark 
varies a good deal according to the age of the tree, as 
well as the thickness, collection, and preservation of the 
bark. The average quantity of acid I obtained from 
two pounds of good thick bark was nearly one ounce. 
Properties, etc. —When solid, ailanthic acid is of a waxy 
consistence, reddish-brown, becoming dark coloured when 
liquefied, almost inodorous, deliquescent, very soluble in 
water, much less so in alcohol or ether, insoluble in chlo¬ 
roform or benzole. It is uncrystallizable and is ex¬ 
tremely prone to become glutinous, even when kept in a 
stoppered phial; on account of its hygroscopic proper¬ 
ties, it swells so much as to be preserved with great diffi¬ 
culty in an ordinary bottle. Its aqueous solution ab¬ 
sorbs oxygen. When heated, it swells, bums, and leaves 
ash, consisting chiefly of carbonate of lime and salts of 
alumina. Its taste is purely and strongly bitter, it red¬ 
dens litmus, is neutralized by alkalies and strong earths, 
forming combinations which are devoid of bitterness. 
Its compound with ammonia is readily decomposed by 
heat, leaving the acid free. It decomposes the carbo¬ 
nates of alkalies, of earths, and of several metals, espe¬ 
cially when aided by heat, and takes the place of car¬ 
bonic acid, which escapes with effervescence; the com¬ 
pounds thus formed are all more or less soluble in water 
and are bitter. When heated along with a strong solution 
of caustic potash, ammoniacal fames are given off, indi¬ 
cating the presence of nitrogen in its composition. When 
heated along with strong sulphuric acid, it becomes 
blackened and a penetrating odour is evolved. Hydro¬ 
chloric acid produces no change when cold, but, on boil¬ 
ing, it changes its colour to a deep dark red. Nitric 
acid oxidizes it immediately with the production of effer¬ 
vescence (from the escape of nitrogen), especially when 
boiled, it makes the liquid clearer and paler. Chromic 
acid produces no change. Tincture of galls gives no 
precipitate. Protonitrate of mercury solution gives a 
copious white precipitate, which is blackened by the ad¬ 
dition of ammonia; this forms one of its characteristic 
tests. Persalts of mercury give no precipitate. Chlo¬ 
ride of gold gives a dirty purple precipitate, which slowly 
exhibits greenish and purplish tints by reflected light. 
Chloride of platinum gives no precipitate. Nitrate of 
silver gives a whitish precipitate, which soon turns dark 
coloured. Diacetate of lead gives a white precipitate, 
but does not throw down the whole of the ailanthic acid. 
Acetate of lead produces no change. No evident changes 
were produced under the following tests:—Chlorine 
water and ammonia ; oxalate of ammonia; red and yellow 
prussiates of potash; sulphocyanide of potassium ; proto¬ 
chloride of tin; potassio-tartrate of antimony; proto- 
and per-salts of iron; and sulphate of copper. 
Ailanthic acid does not possess the power of setting free 
iodine from a solution of iodide of potassium. A con¬ 
centrated solution of it dissolves oxalate of lime. 
Ailanthate of Lime. —In this form ailanthic acid exists 
in nature. It is soluble in water, forming a pale orange- 
coloured solution, which is very bitter. Oxalic acid and 
oxalate of ammonia separate the lime from combination. 
It can be dried into a hard, solid, reddish-brown mass, 
which, when exposed to air, attracts moisture, but less 
quickly than the pure acid, and is less sticky to the feel. 
When drying, it swells much more than the pure acid* 
Its taste is not so bitter as that of the pure acid; it dis¬ 
solves freely in water, and is uncrystallizable. 
Ailanthate of Lead. —This compound is formed during 
the preparation of ailanthic acid. It is of an ochre-yellow 
colour when fresh, but changing to a darker red when 
kept. When hot and dry, it is hard and brittle like 
* In this process ailanthic acid still retains a small percent¬ 
age of uncrystallizable sugar, which is difficult of removal* 
