November 11,1871.] THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
395 
One hundred parts of fresh root yield on perfect desic¬ 
cation twenty parts of dried substance. The roots as im¬ 
ported always contain sixteen or eighteen per cent, of 
water; the fresh roots, therefore, give 24 or 25 per cent, 
of commercial madder. Dutch and Alsacian madder, 
after being ground, is stored in large casks, and kept for 
two or three years, when the colouring matter is de¬ 
veloped, and its tinctorial power is much increased; if, 
however, it is kept five or six years, further changes 
■ensue, and its value seriously decreases. French Avig¬ 
non madder can he employed at once, although the qua¬ 
lity is much improved by keeping it one or two years. 
The best Avignon madders are grown on lime forma¬ 
tions. The roots that have a red colour are called palus , 
and those that are pink rosees ,—the former being con¬ 
sidered the finest. The value of these madders is in 
ratio to the fineness of their powder, the finer powder 
•containing the most colouring matter. 
The nature of the chemical changes occurring in 
madder during the time it is stored, and which so much 
improves its commercial value, was entirely unknown 
until the elaborate and interesting researches of Dr. E. 
Schunck, F.R.S., published in the year 1851. Tie suc¬ 
ceeded in isolating a peculiar ferment called Erythrozym, 
w r hich possesses the property of decomposing a substance 
called by him Rubian. Rubian may be considered as a 
-glucoside (this name being given by chemists to com¬ 
pounds of sugar with other organic principles), and is 
^decomposed by erythrozym into a peculiar sugar and 
Alizarine. Whether there are in the rubia-root several 
-glucosides which unfold themselves respectively into 
sugar and one of the colour-giving principles, or there 
Is only one glucoside, and its colour-giving principle as 
it is liberated gets successively oxidized into alizarine, 
■purpurine, etc., is not yet satisfactorily determined. 
Still, this valuable discovery of Dr. Schunck has thrown 
much light on the subject, and has led to several im¬ 
portant commercial improvements, to which I shall call 
your attention as I proceed. One hundred parts of dried 
madder-root consist of— 
Soluble in cold water ........ 55 parts. 
'Soluble in boiling water, and which contains 
the greater part of the colour-giving prin¬ 
ciples ..3 ,, 
Soluble in alcohol ......... T5 „ 
Fibrous matter.40-5 „ 
I shall make no remark on the gum, mucilage, pectine, 
pectic acid, and pectates which the rubia-root contains, 
hut state that the water extract contains also the yellow 
•colouring-matter discovered by Kuhlmann in 1824, and 
■called by him Xanthine; but this colour has never re¬ 
ceived any commercial application, from its want of bril¬ 
liancy. Water also dissolves another colouring principle 
called Chlorogenine , which is decomposed by weak acids 
into sugar and a brownish-green matter. Both these 
•colouring substances are sources of annoyance to the 
calico-printer, as they render very difficult the obtaining 
of pure whites in printed goods, and they dim the bril¬ 
liancy of the shades produced by the combination of ali¬ 
zarine and purpurine with the mordants. Further, the 
cold water dissolves the sugar contained in the root, and 
on the Continent it is transformed into alcohol. The 
yield of alcohol varies with the nature of the root, and 
ranges between 7 and 10 lb. per cwt. of root. This fact 
•shows that there is from 10 to 15 per cent, of sugar in 
■the root. 
Messrs. Julian and Roquet have based on the above 
facts a commercial process for preparing a purified mad¬ 
der, which they call Jleurs de garance , of which several 
million pounds are now manufactured in France per 
annum. It not only yields brighter colours than the 
original madder, but, as it does not soil the white parts 
of prints, its use saves the printer much soap and 
-labour. To prepare the Jleurs de garance , the madder is 
mixed with eight or ten parts of water, and left for three 
or four days at a temperature of 75° to 80° F., when fer¬ 
mentation ensues, transforming the sugar of the root 
into alcohol, which is collected. The madder, deprived 
of all soluble substances, is dried, and ready for use. 
A hundred parts of madder yield from 55 to 60 per cent, 
of Jleurs de garance. I may state, en passant , that the 
injury which Dutch and Alsace madders sustain when 
kept too long in casks is doubtless owing to the fact 
that, after the erythrozymic fermentation is completed, 
an alcoholic and lactic one sets in, w r hich acts injuriously 
on the colour-giving principles. 
I now proceed to lay before you the outlines of two 
interesting processes for extracting commercially the 
two useful colour-giving principles, Alizarine and Pur¬ 
purine. 
The first is due to M. Leitenberger, and is based on the 
fact that purpurine is soluble in water at 130° F., whilst 
alizarine only dissolves at 170° F. He mixes madder 
with water, and heats the whole gradually, by means of 
a jet of steam, to 130°, at which temperature it is main¬ 
tained for some time. The liquor is then run off and 
filtered. To the clear solution, lime, or, still better, 
baryta, is added, w 7 hen a lake pi-ecipitates. This is 
washed and mixed with hydrochloric acid. The pur¬ 
purine thus liberated is thrown on a filter, washed, and 
is ready for use. The madder remaining from the above 
operation is dried and heated in close vessels with w 7 ood 
spirit, which dissolves the alizarine. This extract, thus 
obtained, after being concentrated by distillation, is 
ready for use. A hundred parts of root yield from two 
to three per cent, of purpurine, and four or four and a 
half per cent, of alizarine. 
The second process, that of Professor Smile Kopp, is 
based on another discovery of Dr. Schunck, namely, that 
weak acids acts upon rubian in the same manner as 
erythrozym, unfolding it into sugar and alizarine. M. 
Kopp found, some years since, that sulphurous acid 
dissolved the glucosides of purpurine and alizarine, 
and applied this observation as follows:—600 lb. of 
Alsace madder are macerated for twelve or fifteen hours 
with 800 gallons of a weak solution of sulphurous acid, 
to which is added one-thousandth part of hydrochloric 
acid, to neutralize the earthy carbonates existing in the 
root. This operation is repeated three times. To the 
liquors, three per cent, of sulphuric acid are added, and 
the whole heated to a temperature not exceeding 140° F., 
when red-coloured flakes separate and gradually deposit, 
which, when washed and dried, are commercial pur¬ 
purine. The liquor is then carried to the boil for a 
couple of hours, and allowed to cool, when a dark green 
powder is found deposited in the vessels, which, when 
washed and dried, is commercial alizarine. 
This process has been carried out by Messrs. Schaaffer 
and Lauth for many years, and no doubt yields a larger 
amount of colour-giving principle than M. Leitenberger’s 
method, the glucosides being doubtless more completely 
decomposed by the acids than by water alone. It has 
the further advantage of obtaining the colouring matters 
free at once, which have only to be washed to be ready 
for use. 
The dyeing power of the alizarine thus obtained is 
equal to forty times its weight of madder, or ten times 
that of garancine. These colouring substances, except 
green alizarine, are not substituted for madder in the 
dyebeck, but are printed on the cloth and steamed, as 
will be described further on. 
M. Kopp found that his green alizarine is a mixture of 
alizarine with chlorogenine; and that this latter body can. 
be separated by treating the mixture with a light oil of 
tar, having a boiling-point of 300° which dissolves the 
chlorogenine. Alizarine is employed in the production 
of rich purples, whilst purpurine is used for reds and 
pinks. _ 
Before describing pure alizarine and purpurine, I may 
state as a fact very interesting, although of no commercial 
value, that if superheated steam be passed over a prepa- 
