April 20,1872.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
845 
55 
grs. 
sulphuric acid then precipitated with chloride of 
barium solution. The precipitated sulphate of 
barium when washed and dried indicated 
anhydrous sulphurous acid. 
II. 100 grs. of the salt dissolved, and tested with 
P.B. vol. sol. iodine, indicated almost the same. 
The salt-crystallizes with 0 molecules of water, the 
whole of which is given off at 100° C. The crystals 
prepared as above and dried in the air or over 
sulphuric acid give the formula of 
Mg'2S0 3 '6H,0. 
and at 100° C., Mg 2S0 3 . 
Thus theory would give a percentage of 54'7 of 
anhydride, while analysis gives 55 in the crystals. 
THE PREPARATION OF CHRYSAMMIC 
ACID AND CHRYSAMMATES. 
BY WILLIAM A. TILDEX, D.SC. LOXD, 
These beautiful compounds are usually prepared 
from aloes, but the soluble extractive matters which 
constitute at least half of the crude drug, yield little 
but picric and oxalic acids, and the resinoid gives a 
mere trifle of chrysammic acid. 
I find it preferable, therefore, to employ for the 
manufacture of aloetic and chrysammic acids the 
aloin of Barbadoes aloes, which, since the discovery 
of Fluckiger’s ‘ nataloin’ would be appropriately 
named barbaloin. The following is an outline of 
the process I adopt. Fine Barbadoes aloes must be 
selected; and the variety which has a rich brown, 
not dark, colour and powerful odour, yields the best 
result. One part of such aloes is dissolved by r agi¬ 
tation with seven or eight parts of boiling water, 
slightly acidulated with hydrochloric acid. The 
solution is allowed to cool and to remain at rest for 
twenty-four hours, when it may be strained to re¬ 
move the deposited resin. It is then evaporated 
down in an open dish till a syrupy consistence is at¬ 
tained, and there remains rather less than two parts 
of liquid. This, set aside for a day or two, solidifies 
in consequence of the formation of a mass of granular 
crystals. The whole is drained in a calico bag, and 
then submitted to gradually increasing pressure till 
entirely free from the black mother-liquor. In this 
way a lemon-yellow mass of barbaloin results, which 
amounts to from 20 to 25 per cent, of the aloes 
if a proper selection has been made. To render it 
quite pure, it requires one or two crystallizations from 
rectified spirit, but for the preparation of chrysammic 
acid this is unnecessary. It has only to be dried 
and powdered and introduced in small portions into 
about six times its weight of fuming nitric acid 
(sp. g. 1*45), kept cool. After standing a few hours, 
about half its volume of water is added and heat ap¬ 
plied until, in consequence of the formation of deposit, 
the liquid bumps. During this digestion, a consider¬ 
able quantity of carbonic anhydride escapes with the 
nitrous fumes. A further quantity of water is then 
added, and when cold the bright yellow crystalline 
deposit of aloetic and clirysammic acids filtered off. 
The liquid retains oxalic and picric acids, together 
with a small quantity of aloetic acid, which may be 
recovered by distilling away the nitric acid and 
washing the residue with water. The mixture of 
aloetic and chrysammic acids thus obtained is dried 
and boiled gently for eight or ten hours with sufficient 
nitric acid to cover it. Water is again added, and 
the crystalline precipitate collected and washed till 
the washings become pink. It is then boiled for 
an hour with about an equal weight of potassic 
acetate dissolved in fifty parts of water. The solu¬ 
tion thus obtained deposits on standing a copious 
crystallization of green sparkling potassic clirysam- 
mate, which may be washed with a little cold water. 
The mother-liquors, which retain potassic aloetate, 
are evaporated down, acidified by nitric acid, and 
the aloetic acid converted into chrysammic acid by 
further treatment with nitric acid, as already 
described. 
Proceeding in this way, barbaloin readily yields 
more than a third of its weight of pure potassic 
chrysammate. 
Chrysammic Acid. —Crystals of chrysammic acid 
are best obtained by dissolving potassic chrysam¬ 
mate in a considerable quantity of boiling water, 
and strongly acidifying the liquid with acetic acid. 
Thin yellow fern-leaves, a quarter of an inch long, 
mixed with a few long red crystals, are deposited in 
a few hours. On warming the whole gently, the 
latter are redissolved, and the yellow fern leaves 
which are mixed with a few much smaller tables 
may be filtered off and washed. They consist of pure 
chrysammic acid ; in mass they strongly resemble 
picric acid, but are more lustrous. 
After exposure to dry air at ordinary temperatures 
for a few days, they suffer no loss of weight by heat¬ 
ing to 150° C. Evaporated with pure sulphuric acid, 
they leave no residue. 
Lead Chrysammate. Described by Schunck and 
Mulder as a red powder containing variable pro¬ 
portions of lead. It may easily be obtained, how¬ 
ever, beautifully crystallized, by mixing a boiling 
solution of potassic chrysammate with a slight excess 
of plumbic acetate dissolved in boiling water and 
acidified with acetic acid. On cooling, long thin 
prisms, exhibiting a magnificent bronze reflection, are 
formed. The light transmitted by the crystals is 
pale red and strongly polarized, so that on viewing, 
by means of a lens, some ot them suspended in the 
mother-liquor, the light is seen to be completely cut 
off, when two of them cross each other at right angles. 
Mounted properly, they form a pretty microscopic 
object. 
The salt was found to have the formula 
Pb'(N0 2 ) 4 0 4 .4H„0. 
Theory. 
HoO 
Pb 29-69 
Barium Chrysammate. Hitherto described is a 
red powder. Obtained in the crystalline foim by 
mixing boiling solutions of potassic clii} sammate 
and barium chloride acidified with acetic acid. It 
appears to be one of the most insoluble of the chi} - 
sammates, as the mother-liquors left after the 
crystallization of the salt are almost colouiless. 
forms brown shining needles, which, however pre¬ 
sent none of the green or golden lustre so noticeaU i 
in most of the other salts. . 
The formula seems to be the same as that assigned 
Mulder to the uncrystallized compound, 
c 14 h s 
10'33 
Experim nt. 
10*18 
26*9 2 
hy 
VIZ. 
'14 
H 2 Ba" (N0 2 ) 4 0 4 2H 2 0. 
Theory. 
Experiment. 
2277 
Ba 23'IS 
Potassium Chrysammate crystallizes in two forms; 
