quantities of other organic substances, which often render the isolation of a single alkaloid in the pure state very difficult.
As to the chemical constitution of alkaloids, very little is as yet known. It has been found, however, that most of these substances are tertiary aromatic bases, and that by far the greater number of them contain one or more methoxy-groups, OCH;,, linked to a benzene nucleus. The chemical relationship of the alkaloids to pyridine, quinoline, and uric acid, has been mentioned above. Most alkaloids have a powerful physiological action even if employed in very small quantities. The action of certain alkaloids is, however, at least partly antagonistic to the action of certain others. For this reason one alka- loid may sometimes be employed to relieve the poisonous effect of another alkaloid, though it may itself be a violent poison. The antagonism of morphine and atropine is of considerable value in cases in which a subcutaneous injection of morphine is indicated: the cardiac depression, indigestion, and constipation, usually caused by morphine, may be prevented by injecting sim- ultaneously a trace of atropine.
The alkaloids are sometimes spoken of as vegetable bases, natural organic bases, or vegetable alkaloids. The latter name is applied to them in contradistinction to the animal alkaloids, or ptomaines, that are formed during the putrefaction of animal products. Like the vegetable alkaloids, the ptomaines are highly poisonous nitrogenous bases, and they resemble the vegetable alkaloids both in their chemical properties and in their physiological action. See Ptomaines.
Bibliography. Pictet, La constitution chimique des alcaloïdes végéteaux (second edition, Paris, 1897; German translation, Berlin, 1891); Dupuy, Alcaloïdes (Brussels, 1887-89); Schmidt, Ueber die Erforschung der Konstitution und die Versuche zur Synthese richtiger Pflanzenalkaloide (Stuttgart, 1900); Bruhl, Die Pflanzenalkaloide (Brunswick, 1900). The most important alkaloids are described in some detail under their special names.
AL'KANET (dim. of Sp. alcana, alhena,
from Ar. «/, the -f- hinnd) , Anchusa. A genus of
plants belonging to the natural order Boragi-
nacece. The species are herbaceous plants, rough
with stiff hairs, and having lanceolate or ovate
leaves, and spike-like, bracteated, lateral, and ter-
minal racemes of flowers, which very much resem-
ble those of the species of Myosotis, or forget-me-
not. The common alkanet {Anchusa officinalis)
grows in dry and sandy places, and bj' waysides,
in the middle and north of Europe. It is rare
and a very doubtful native in Great Britain.
The tlow'ers are of a deep purple color. The
roots, leaves, and flowers were formerly used in
medicine as an emollient, cooling, and soothing
application. The Evergreen Alkanet (Anchusa
sempcrvirens) is also a native of Europe, and a
doubtful native of Great Britain, although not
uncommon in situations to which it may have
escaped from gardens, being often cultivated for
the sake of its beautiful blue flowers, which ap-
pear early in the season, and for its leaves,
which retain a pleasing verdure all winter. It
is a plant of humble growth, rising only a few
inches above the gi-ound. A number of other
species are occasionally seen in our flower bor-
ders. Anchusa tinctoria, to which the name
Alkanet or Alkanna (Ar. al-chenneh) more
strictly belongs, is a native of the Levant and
of the south of Europe, extending as far north
as Hungary. The root is sold under the name
of alkanet or alkanna root; it is sometimes cul-
tivated in England; but the greater part is im-
ported from the Levant or. the south of France.
It appears in commerce in pieces of the thick-
ness of a quill or of the finger, the rind blackish
externally, but internally of a beautiful dark-
red color, and adhering rather loosely to the
whitish heart. It contains chiefly a resinous red
coloring matter, to which the name alkanet is
often applied. (See Alkanet below.) Vir-
ginian alkanet is probably a species of the genus
Lithospcrmum.
ALKANET. A beautiful red coloring mat-
ter obtained from the roots of the alkanet or
orchanet herb (Anchusa tinctoria, Tausch.) and
largely used for imparting a, red color to var-
nishes, cosmetics, etc. It is extracted from the
roots by means of benzine, and, on evaporating
the latter, is obtained in the form of a thick
paste thatr is insoluble in water, but readily
soluble in alcohol, ether, benzine, various oils,
and other oi'ganic liquids. Alkanet should not
be confounded with the red coloring matter con-
tained in the roots of the henna, or alcanna,
plant (Lau'sonia incrmis L.). The chemical
composition of purified alkanet seems to corre-
spond to the formula CsHuO,.
AL'KEKEN'GI. See Physalis.
AL-KHUWARIZMI, al-Ku'wariz'me, Abu 'Abd Allah Mohammed ibn Musa, of Khuwarism, a province in which Khiva is now located. (?-c.831). A Moslem philosopher, and the most celebrated algebraist of his time. He was one of the savants who went to Bagdad in Al-Mamun's reign. He worked in the obervatory there, computed a
set of astronomical tables and wrote several works
on mathematics. Among these works were treatises on the Hindu arithmetic (transl. Gerard of Cremona, or Adelard of Bath; published by Boncompagni, Rome, 1857), the sun-dial, the astrolabe (an instrument used to take the altitude of the sun), on chronology, geometry, and algebra. His Al-jabr wa'l muqabalah, i.e. the redintegration and the comparison, gave the name to alge-
bra (q.v.). His discussion of the quadratic
equation, in which he called to his assistance
geometric diagrams, is quite complete. His name
appeared in Latin in the form Algoritmi, from
which we have our word algorism (q.v.). His
algebra was translated into Latin by Gerard of
Cremona, and into English by F. Rosen (London, 1831). Consult Brockelmann, Geschichte der arabischcn Litteratur (Weimar, 1898, part i., p. 215.).
AL-KINDI, ȧl-kēn'dḗ, or ALCHINDIUS,
ăl-kĭn'dĭ-ŭs, Abu Yusuf Ya‘ḳub ibn Isḥak al-Kindi. An Arabian philosopher, who flourished in the ninth century. He wrote more than two hundred treatises on almost everything within the range of the philosophy and science of his time. By the Arabs themselves he is viewed as the Peripatetic philosopher in Islam. Of his many works, but a few on medicine and astrology remain. Consult the study by Flügel (Leipzig, 1857), and A. Nagy, Die philosophischen Abhandlungen des al-Kindi (Münster, 1897).
ALKMAAR, alkniiir'. An old town in the province of North Holland, in the Netherlands, situated on the North Holland Canal, 20 miles northwest of Amsterdam (Map: Netherlands,
