426 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. [November 25, 1871. 
conviction that the alcoholic menstruum possesses supe¬ 
rior advantages over that of the aqueous one; for by 
means of it there is obtained directly, by the process of 
percolation, a more highly concentrated solution, obviat¬ 
ing the long and tedious application of heat necessary 
to reduce the aqueous solution to a proper strength, 
thus more than counterbalancing whatever advantages, 
if any, therapeutically, the aqueous may have been sup¬ 
posed to possess over the spirituous solvent. 
It has doubtless been owing to the tedious and ineffi¬ 
cient methods heretofore in vogue in the manufacture 
of this syrup that this formula has been discarded 
from our Pharmacopoeia, and to its partial disuse in 
professional practice. It is certainly, however, when 
properly prepared, an efficient, useful and convenient 
preparation for children, for whom it was originally 
intended; and if a reliable and satisfactory formula, 
such as we present, should be adopted in its manufac¬ 
ture, its restoration to its former place in professional 
favour will doubtless follow.— Amer. Journ. Pharm. 
THE MOST IMPORTANT METHODS OF DETER¬ 
MINING ARSENIC VOLUMETRICALLY. 
BY E. WAITZ.* 
The author has investigated with great care the dif¬ 
ferent methods for determining arsenious acid, viz., 
1st, by means of free iodine; 2nd, by means of dipo- 
tassic dichromate; 3rd, by means of potassic permanga¬ 
nate ; as well as the method for estimating arsenic acid 
by means of uranic acetate. 
The iodine method depends, as is well known, upon 
the conversion of arsenious into arsenic acid in alkaline 
solution. In an acid solution arsenious acid can exist in 
the presence of iodine or chlorine, and is only partly 
converted into the higher oxide. The alkali must be in 
the form of a carbonate, for a caustic alkali combines 
with the iodine. The author’s experiments show that 
normal sodic carbonate fixes iodine, but that the acid 
carbonate does not; a solution saturated in the cold 
should be used. This only confirms the previous obser¬ 
vations of Fresenius. On employing a standard solu¬ 
tion of arsenious acid in hydrochloric acid, the free acid 
has first to be neutralized by means of caustic soda or 
acid sodic carbonate. With an excess of this latter salt, 
good results were obtained. 
Experiments made with a view of converting precipi¬ 
tated arsenious sulphide into arsenious acid by the 
action of an ammoniacal solution of silver nitrate upon 
the sulphide dissolved in ammonia, as well as by means 
of freshly precipitated bismuthous hydrate, and of sub¬ 
stituting in this manner the trisulphide—which can be 
obtained in a state of great purity—for the trioxide, 
were unsuccessful, as the reaction is never quite com¬ 
plete, owing to the formation of sulpho-salts of silver 
and bismuth. 
The method first proposed by Kessler f of determining 
arsenious acid in an acid solution by means of dipotassic 
dichromate, and standardizing back by means of a ferrous 
sulphate solution, gave good results. Excess of hydro¬ 
chloric acid has to be avoided. Kessler succeeded in 
utilizing arsenious sulphide by treating it m a hydro¬ 
chloric acid solution with mercuric chloride, a saturated 
solution of which converts the sulphide slowly at the 
ordinary temperature, more rapidly on the application 
of a gentle heat, into the trioxide. The reaction is over 
when the mass has become white. The author’s experi¬ 
ments show further that the mixture of trisulphide and 
sulphur which is obtained when a solution of arsenic 
acid is precipitated with sulphuretted hydrogen, cannot 
* Zeitschr. f. Anal. Chem. x. 158-183; from the Journal 
of the Chemical Society. 
t Fogg. Ann. cxviii. 17, and Fres. Zeitschr. fur Anal. 
Chemie, ii. 383. 
be converted directly into arsenious acid by digestion 
with mercuric chloride, on account of the dense nature 
of the precipitate, but that it is readily acted upon, after 
dissolving out the trisulphide by means of dilute am¬ 
monia and reprecipitating with hydrochloric acid. 
The oxidation of arsenious into arsenic acid by means 
of potassic permanganate is never perfect, * and a volu¬ 
metric method based upon this reaction w r as found by 
the author to be most untrustworthy; but by adding 
excess of permanganate—more than double the amount 
required according to theory—and standardizing back 
with a solution of ferrous sulphate, very accurate results 
were obtained. 
The volumetric determination of arsenic acid by means 
of uranic acetate in the presence of free acetic acid and 
an alkaline acetate, did not yield trustworthy results. 
THE ACTIVE PRINCIPLE OF POLYGONUM 
HYDROPIPER. 
BY C. J. BADEMAKER, M.D. 
Plaving seen hydropiper frequently used, both in tho 
form of tincture and fluid extract in amenorrhoea and 
other uterine disorders, with very satisfactory results, I 
was induced to make a chemical examination of this 
drug. 
In order to obtain the active principle or principles, 
the following processes were resorted to: — 
Experiment LA—Two pounds of the herb were ex¬ 
hausted with diluted alcohol, the alcohol distilled off by 
means of a water-bath, the remaining liquid was evapo¬ 
rated to about one-third of the original bulk; during 
the evaporation a considerable amount of resinous matter 
was precipitated, the solution was filtered from the re¬ 
sinous precipitate and the filtrate treated with basic ace¬ 
tate of lead, which produced a yellow precipitate. 
The precipitate produced was collected on a filter and 
washed with distilled water. The precipitated magma 
was then suspended in distilled water and treated with 
sulphuretted hydrogen; the resulting mixture of sul¬ 
phide of lead and organic principle was treated with 
ether, the ether separated from the sulphide of lead and 
allowed to evaporate spontaneously. 
The crystals thus formed were soluble in alcohol, 
ether, chloroform, and slightly soluble in diluted alco¬ 
hol, but almost insoluble in water; when rubbed with 
water they become very sticky; the solution of the 
crystals had an acid reaction with litmus. Under the 
microscope they made a beautiful appearance, resembling 
the crystals of uric acid of human urine. 
This acid may he called polygonic acid. 
Experiment < lnd .—The filtrate from which the acid had 
been removed by means of basic acetate of lead, was 
treated with sulphuric acid, in order to remove the ex¬ 
cess of lead, and then rendered alkaline by means of 
caustic potash and treated with ether. 
The ether was separated and allowed to evaporate 
spontaneously. The mass thus left was perfectly white, 
neutral to test-paper, and had a bitter taste, was soluble 
in alcohol, ether, and the mineral acids ; its solution in 
acids was not precipitated by ammonia, caustic potash, 
or sodic carbonate, nor was I able to obtain any crystals. 
From [this I concluded that it possessed no basic pro¬ 
perties. 
Experiment 3rd .—One pound of fluid extract (480 grs. 
to the fluid ounce) was treated with hydrochloric acid, 
about five drops of the acid to each fluid ounce of the 
liquids, and then treated with ether. The ether sepa¬ 
rated and treated with basic acetate of lead, the precipi¬ 
tate produced was collected on a filter and washed with 
distilled water, the precipitated magma was suspended 
in distilled water and treated with sulphuretted hydrogen. 
The mixture of sulphide of lead and organic principle 
* Gmelin, Handbuch der Chem. 4th ed. ii. p. 640. 
