The latter product is an amorphous mass agreeing with kino-red; by
heating it at 160-170° it again loses water, thus affording another
anhydride.
Etti succeeded in preparing methylic chloride, pyrocatechin CH₄(OH)₂ as
well as gallic acid C₇H₆O₅, by decomposing kinoïn.
We have prepared kinoïn from _Australian kino_ (see page 198), but
failed in obtaining it from Malabar kino, which however Etti states to
have used. Kino affords about 1½ per cent. of kinoïn.
The solutions of kinoïn turn red on addition of ferric salts.
Commercial kino yielded us 1·3 per cent. of ash.
=Commerce=—The quantity of true kino collected in the Madras forests is
comparatively small, probably not exceeding a ton or two annually. The
drug is often shipped from Cochin.
=Uses=—Kino is administered as an astringent. It is said to be used in
the manufacture of wines, and it might be employed if cheap enough in
tanning and dyeing.
Other sorts of Kino.
1. _Butea Kino_, _Butea Gum_, _Bengal Kino_, _Palas or Pulas Kino_,
_Gum of the Palas or Dhak Tree_.
This is an exudation from _Butea frondosa_ Roxb. (_Leguminosæ_), a
tree of India and Burma, well known under the name of _Palas_ or
_Dhak_, and conspicuous for its splendid, large, orange, papilionaceous
flowers.[773] According to Roxburgh it flows during the hot season from
natural fissures or from wounds made in the bark, as a red juice which
soon hardens into a ruby-coloured, brittle, astringent gum.
[772] We have to thank Mr. Broughton, late of the Cinchona Plantations,
Ootacamund, for determining this point. In the bark almost saturated
with fresh liquid kino, he utterly failed to obtain any indication of
pyrocatechin by the tests which he found to render it easily evident in
dry kino.
[773] See Nees von Esenbeck, _Plantæ medicinales_, Düsseldorf, iii.
(1833) tab. 79.
Authentic specimens of this kino have been placed at our disposal by
Mr. Moodeen Sheriff of Madras and by Dr. J. Newton of Bellary. That
received from the first-named gentleman consists of flattish, angular
fragments (the largest about ½ an inch across) and small drops or
tears of a very dark, ruby-coloured gum, which when held to the light
is seen to be perfectly transparent. The flat pieces have been mostly
dried on leaves, an impression of the veins of which they retain on
one side, while the other is smooth and shining. The substance has a
pure astringent taste, but no odour. It yielded us 1·8 per cent. of ash
and contained 13·5 per cent. of water. Ether removes from it a small
quantity of _pyrocatechin_. Boiling alcohol dissolves this kino to the
extent of 46 per cent.; the solution which is but little coloured,
produces an abundant greyish-green precipitate with perchloride of
iron, and a white one with acetate of lead. It may be hence inferred
that a tannic acid, probably kino-tannic acid, constitutes about half
the weight of the drug, the remainder of which is formed of a soluble
mucilaginous substance which we have not isolated in a state of purity.
By submitting the Butea kino of Mr. Moodeen Sheriff to dry distillation
we obtained pyrocatechin.
The sample from Dr. Newton is wholly in transparent drops and
stalactitic pieces, considerably paler than that just described, but of
the same beautiful ruby tint. The fragments dissolve freely and almost
completely in cold water, the solution being neutral and exhibiting the
same reactions as the former sample.
Butea kino, which in India is used in the place of Malabar kino, was
long confounded with the latter by European pharmacologists, though
the Indian names of the two substances are quite different. It is not
obtained exclusively from _B. frondosa_, the allied _B. superba_ Roxb.
and _B. parviflora_ Roxb. affording a similar exudation.
2. _African or Gambia Kino._—Of this substance we have a specimen
collected by Daniell[774] in the very locality whence it was obtained
by Moore in 1733 (see p. 195), and by Park at the commencement of the
present century. The tree yielding it, which still bears the Mandingo
name _Kano_, and grows to a height of 40 to 50 feet, is _Pterocarpus
erinaceus_ Poiret, a native of Tropical Western Africa from Senegambia
to Angola. The juices exude naturally from crevices in the bark, but
much more plentifully by incisions; it soon coagulates, becoming deep
blood-red and remarkably brittle. That in our possession is in very
small, shining, angular fragments, which in a proper light appear
transparent and of a deep ruby colour. In solubility and chemical
characters, we can trace no difference between it and the kino of the
allied _Pt. Marsupium_ Roxb. This kino does not now find its way to
England as a regular article of trade. From the statement of Welwitsch,
it appears that the Portuguese of Angola employ it under the name of
_Sangue de Drago_.[775]
3. _Australian, Botany Bay, or Eucalyptus Kino._—For some years past,
the London drug market has been supplied with considerable quantities
of kino from Australia; in fact at one period this kino was the only
sort to be purchased.
[774] See his paper _On the Kino Tree of West Africa, Pharm. Journ._
xiv. (1855) 55.
[775] _Madeiras e Drogas medicinaes de Angola_, Lisboa, 1862, 37.
As it is the produce of numerous species of _Eucalyptus_, it is not
surprising that it presents considerable diversity of appearance. The
better qualities closely agree with Pterocarpus kino. They are in
dark reddish-brown masses or grains, which when in thin fragments are
seen to be transparent, of a garnet red hue and quite amorphous. The
substance is mostly collected by the sawyers and wood-splitters. It is
found within the trunks of trees of all sizes, in flattened cavities of
the otherwise solid wood which are often parallel to the annual rings.
In such place the kino, which is at first a viscid liquid, becomes
inspissated and subsequently hard and brittle. It may also be obtained
in a liquid state by incisions in the stems of growing trees: such
liquid kino has occasionally been brought into the London market; it is
a viscid treacle-like fluid, yielding by evaporation about 35 per cent.
of solid kino.[776]
Authentic specimens of the kino of 16 species of _Eucalyptus_ sent
from Australia by F. von Müller, have been examined by Wiesner of
Vienna.[777] He found the drug to be in most cases readily soluble in
water or in spirit of wine, the solution being of a very astringent
taste. The solution gave with sulphuric acid a pale red, flocculent
precipitate of _Kino-tannic Acid_; with perchloride of iron (as in
common kino) a dusky greenish precipitate,—except in the case of the
kino of _E. obliqua_ L’Hér. (Stringy-bark Tree), the solution of which
was coloured dark violet.
Wiesner further states, that Eucalyptus kino affords a little
_Catechin_[778] and _Pyrocatechin_. It contains no pectinous matter,
but in some varieties a gum-like that of _Acacia_. In one sort, the
kino of _E. gigantea_ Hook,[779] gum is so abundant that the drug is
nearly insoluble in spirit of wine.
By Etti’s process, as given at page 197, we obtained kinoïn from an
Australian Kino, which contained numerous fragments of the wood. We
noticed that both Australian and Malabar kino emitted a somewhat
balsamic odour, when they were treated with hydrochloric acid.
From this examination, it is evident that the better varieties of
Eucalyptus kino, such for instance as those derived from _E. rostrata_
Schlecht. (_Red_ or _White Gum_, or _Flooded Gum_ of the colonists),
_E. corymbosa_ Sm. (_Blood-wood_) and _E. citriodora_ Hook., possess
the properties of Pterocarpus kino and might with no disadvantage be
substituted for it.
[776] Victoria Exhibition, 1861.—Jurors’ Report on Class 3. p. 59.
[777] _Zeitschrift des österreich. Apotheker-Vereines_ ix. (1871) 497;
_Pharm. Journ._ Aug. 5, 1871. 102.
[778] In our opinion this is doubtful.
[779] Bentham unites this species to _E. obliqua_ L’Hér (_Flor. Austr._
iii. 204).