January 27, 1872.] 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
615 
Gall-nuts are employed to produce blacks on silks, in 
the preparation for Turkey-red, to produce fast blacks 
in calico-printing, and, lastly, large quantities are used 
in tlie manufacture of pyrogallic acid, the consumption 
of which in the present large requirements of photogra¬ 
phy must be enormous. We shall see, as we proceed, 
that gall-nuts are the only available tannin matter for 
production of this acid. 
An inferior quality of gall-nut is also sold, which is 
found on the Quercus robur , which grows in Hungary, 
Styria, Croatia and Piedmont. It is used in those coun¬ 
tries for tanning leather, and in some parts of Germany 
-as a cheap substitute for the Eastern nuts. 
Sumach is, as Dr. Stenhouse’s researches show, the 
•only substance in which the tannin principles are iden¬ 
tical with those of gall-nuts, although in this tannin 
matter there is a comparatively large quantity of gallic 
acid. It also contains a soluble yellow principle. 
Sumach is foimd in commerce as a coarse powder, ob¬ 
tained by the trituration of the young branches and 
leaves of several varieties of the family Terebintliacece. 
The species most cultivated is the Rhus coriaria, -which 
is a plant indigenous to Italy, Sicily, France, Spain and 
Portugal. The shrub grows to a height of sixteen feet 
in the most arid soils, and is very extensively cultivated 
in some of those countries. The twigs and leaves are 
gathered once a year. 
Although sumach varies greatly in the amount of 
tannin it contains, there can be no doubt that from the 
Rhus coriaria is the best, whilst the most inferior comes 
from the south of France, and is the produce of the 
Coriaria myrtifolia. 
In consequence of the powdered state in which sumach 
is sold, it not only varies greatly in quality, but is often 
deliberately adulterated with sand or the leaves of other 
plants. It is easy to discover the sand, it being only 
mecessary to put some of it in water, when the sand, from 
its greater specific gravity, readily falls to the bottom of 
the vessel. I will describe the method of determining 
the amount of tannic acid later on. 
Extract of sumach is sometimes employed in print¬ 
works to produce yellows with acetate of tin, blacks 
and greys with iron mordants, and dark yellow with 
.sulphate of zinc. It is also used to produce blacks on 
woollen fabrics, although it does not give as good blacks 
as gall-nuts. Its principal use, however, is to mordant, 
either alone or in conjunction with salts of tin, the 
cotton warps of the mixed fabrics so extensively manu¬ 
factured in Yorkshire, by which means the cotton takes 
the same colours as the woollen weft, both with vegetable 
dye-stuffs and those derived from coal-tar. 
Sumach is too expensive a tannin matter to be used 
for the tanning of leather, but it is employed by the 
•currier in the preparation of skins for dyeing with light 
shades. 
Valonia is the acorn-cup of the Quercus AEgilops, which 
grows in the isles of the Grecian Archipelago and on the 
coasts of Asia Minor. It is especially employed for tan¬ 
ning leather and adulterating garancine. 
Divi-divi is the pod of the Ccesalpinia [coriaria, and is 
chiefly imported from South America. 
Mjrobalans , which is largely used for tanning leather 
and producing blacks on wools, is the dried nut of the 
Terminalia Chebula , and is imported chiefly from Calcutta. 
Dr. Stenhouse has shown that the tannin matter of 
valonia, divi-divi, myrobalans and oak-bark are not 
identical with those of gall-nuts and sumach. They do 
not yield gallic acid when boiled with dilute sulphuric 
acid, but sugar and some other organic principle. 
From the above facts, it must be obvious to all who 
nse tannin matters, whether dyers or tanners, that these 
substances not only vary in value, according to the 
variety of plant from which they have been obtained 
and the country whence they are imported, but there 
are sources.of deterioration which cannot be detected by 
the eye. Thus, for example, if a new sumach be mixed 
with a comparatively old one, it is impossible to detect 
the fraud. The only method, therefore, of ascertaining 
the value of a sample is to determine chemically the 
amount of tannic acid it contains. This may be done 
by the following process:—A weighed quantity (say 100 
grains) of the substance to be tested is boiled with dis¬ 
tilled water, and the decoction run off into a beaker, with¬ 
out filtering. This process is repeated four or five times. 
A test solution is prepared by dissolving one drachm 
of gelatine in four ounces of water, and adding 15 grains 
of powdered alum to the solution. 155 grains of this 
solution represent 5 grains of pure tannic acid. The 
test fluid is carefully dropped into the beaker, until, 
on the falling of a drop upon the surface, the charac¬ 
teristic ring of tannate of gelatine is no longer pro¬ 
duced. The quantity of test fluid used is then ascer¬ 
tained, and from this the amount of tannic acid is 
calculated. 
Before passing from this class of tannin substances, 
there is one that I must mention, which has been used 
from the most ancient times, in Egypt, Arabia and other 
Eastern countries, to dye wool, horsehair, leather, etc. 
It is the leaves of the Lawson ia inermis , which appears 
to be the gopher wood of Scripture and the hennis of 
the Egyptians. The leaves are mixed with water to 
form a paste of an orange-brown colour. This paste also 
is employed by the Asiatic ladies to dye the nails of their 
hands and feet, as well as their ears and hair. 
Catechu , gambier and gum kino are the most valuable 
of the tannin substances which give a green coloration 
with persalts of iron. They are most extensively used 
to produce a great number of shades, varying from light 
drabs to dark brown, in cheap dyed cotton goods, such as 
fustians and corduroys. They are used in calico print¬ 
ing chiefly to produce browns, in silk dyeing to weight 
the silk, and in tanning to produce a low class of lea¬ 
ther, easily distinguishable from that properly tanned 
with bark and other matters belonging to the first class, 
because, when used for making shoes, it communicates 
to the stockings a peculiar orange-yellow hue. 
For a long time there was much doubt as to the genus 
of plants from which catechu, gambier and kino, which 
resemble each other very closely in their properties, 
were derived. M. Guibourt, a few years ago, solved the 
problem. He found that real catechu , cutcli , or terra 
japonica was the berry of the Areca palm, called Areca 
catechu , and the Acacia catechu; whilst gambier is ex¬ 
tracted from the leaves of the TJncaria Gambir , belonging 
to the family Rubiacece , and kino is obtained principally 
from the Butea frondosa, a leguminous plant. 
Catechu is found in commerce principally in two 
states, the best in lumps varying in weight from 80 to 
90 lb., of a dull purple colour, and covered with leaves ; 
the second, in masses more or less covered with sand. 
Gambier is imported into this country in the form 
of small cubes, having a yellowish-brown colour. 
Good catechu should not leave, on incineration, more 
than 4 or 5 per cent, of ash. Its aqueous solution 
should give, with alcohol or gelatine, an abundant white 
precipitate, with lime and baryta a brown precipitate, 
with salts of lead and tin a yellow precipitate varying in 
shade with the salts employed, and with bichromate of 
potash a brown precipitate. It should also take a de¬ 
cided brown hue with alkalies, and assume a greenish 
colour with salts of iron. 
Catechu, besides naturally varying widely in quality, 
is freely adulterated with mineral substances, starch, 
tannin matters and blood. 
I have just stated the amount of ash a good catechu 
should yield. To ascertain the presence of starch, the 
sample should be first treated with alcohol, and the inso¬ 
luble residue boiled with water, which will give a fine 
blue coloration on the addition of iodine if starch be pre¬ 
sent. The presence of any ordinary tannin matter in 
the catechu will modify the green coloration which the 
latter substance gives with the persalts of iron. Blood 
