Rudolph August Witthaus.

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It is also formed by heating piperazin with zinc dust. Pyrazin and
its homologues are produced during fermentation, and exist in fusel-
oils, and in commercial amylic alcohol. It is a solid; f . p. 55;
b. p. 115; has the odor of heliotrope, and is strongly basic.

The three diazins form condensation products with benzene: the
CH:CH



benzorthodiazins, I /C 6 H 4 , cinnolin, and II /CeH 4 , phthal-



X
/

N N N.CH

azin, and benzometadiazins, and benzoparadiazins.

CH 2 .NH.CH 2
Hexahydro-pyrazin Piperazin Diethylene Diamin I

CH 2 .NH.CH 2

may be obtained by reduction of para-diazin, but is manufactured
from diphenyi-diethylene diamin, CeHs.N^cH^CHa/N-^Hs, which is

obtained by the action of ethylene bromid upon anilin. It crystallizes
in colorless needles; f . p. 104; b. p. 145; soluble in water, and
deliquescent. It is strongly alkaline and basic, and absorbs carbon
dioxid from air. It forms a soluble compound with uric acid (p. 355) ,
and is used medicinally as a solvent for uric acid in lithiasis.

HN.CO.NH
Urazin Diurea I I is the diketonic derivative of sym-

metrical tetrazin (p. 353).



B. CONDENSED HETEROCYCLIC COMPOUNDS.

These compounds, which are more numerous than the correspond-
ing carbocyclic compounds (p. 438), may be considered as being
derived from the latter by substitution of N for methine, =CH ,
or of O, S, or NH in a bivalent position, or, as in the case of
iso-indole (p. 463), by substitution and modification of internal link-
age. The number of these substances is still further increased by
the existence of four ringed-compounds, such as the anthraquinolins
and indigo-blue (p. 466). The formulas on the following page are
those of some of the nitrogen derivatives, in which indole and isoindole
may be considered as derived from indene (p. 438) : carbazole from
fluorene; quinolin, iso-quinolin and naphthydrin from naphthalene:



CONDENSED HETEROCYCLIC NUCLEI



463



acridin and the anthrapyridins from anthracene; and phenanthridin
from phenanthrene :



HC3 C - CHjS

I Bz. || Py. ||
HC2 .C CHa

\1/ \ /

C Nn

H H

Benzo-pyrrole.

(Indole).



H
C

X \

HC C CHa

1 II 1
HC C N

\ /"\ X

C C
H H

Iso-indole.


]

<

HC

HC

\

<

J



C



\



H
C



H

Cy



HC3 C CH/3

I Bz. || Py. |
HC2 C CHa



H
C



HC

I
HC



\



CH

I
N



C CH

II I

C CH

N C
H H

Diphenylene-imid.
(Carbazole).

H H
C C

HC C CH

I II I

HC C CH

\



C N


C C


N N


H


H H




Benzo-pyridin.


Iso-quinolin.


Naphthydrin.


(Quinolin).






H


H H H H H


C


C C C C C


S \ /


' \ X.N X \ /


\ / \>


HC C


C CH HC C


C CH


1 II


II 1 1 II


II 1


HC C


C CH HC C


C N


S / v


JX \ X \ X \


X \ X


c


N C C C C'


H


H H H H


Acridin. a-Anthrapyridin.


H H


H H H


H H


C C


C C=C


C=C


x \ /


\ / \ / \


/ \


HC C


C CH HC C C CH


1 II


II 1 \ - X


\ X


HC C


C CH C C


c-c


\ / \L


/ \ X H \


/ H


c c


N N=C


H H




H


/3-Anthrapyridin. Phenanthridin.



CONDENSED NUCLEI CONTAINING OXYGEN OR SULFUR

MEMBERS.

Of these we will consider only a few of the oxygen compounds:
Coumarone Benzofurfurane (formula p. 464) is formed by

the action of KHO upon the coumarins, and is the parent substance

of two series of substitution derivatives, and /8.

Coumarin, and isocoumarin and their alkyl and phenolic deriva-



464 MANUAL OF CHEMISTRY

tives, e.g. umbelliferone, aesculetin, daphnetin, hesperetin, exist in
different vegetables (pp. 410, 413) . Coumarin is the odorous principle
of Tonka beans, and also exists in a variety of other vegetables. It is
formed by the action of acetic anhydrid and sodium acetate upon
salicylic aldehyde. It forms crystalline needles; f.p. 67; soluble in
water, alcohol and ether. Coumarin and isocoumarin are benzo-
derivatives of a-pyrone (p. 458):

H H H H H

C C C C C

S \ S \ S'\ / \ / \

HC C CH HC C CH HC C CH

I II II I II I I II I

HC C CH HC C CO HC C O

\ / \ / \ / \ / \ / \ /

CO CO C C

H H HO

Coumarone. Coumarin. Iso-coumarin.

Benzo- and dibenzo-7-pyrones, the latter called xanthones, exist
in several natural yellow dyes of vegetable origin, as from quercetin
and chrysin (p. 413).



CONDENSED NUCLEI CONTAINING A NITROGEN MEMBER.
BENZOPYRROLE AND ITS DERIVATIVES INDIGO COMPOUNDS.

Indole Benzopyrrole (formula p. 463) is produced: (1) by
distilling oxindole over zinc -dust; (2) by heating o-nitro-cinnamic
acid (p. 403) with potash and iron filings, or by similar reduction
of other unsaturated o-nitro substitution products of benzene (3)
by the interaction of calcium formate and phenylglycocoll (p.
424) . It is one of the products of putrefaction of the proteins by
anaerobic bacteria, and is formed in the intestine during pancreatic
digestion of those substances. It is partly eliminated with the faeces
and partly reabsorbed, appearing in the urine in su If ocon jugate com-
bination. It crystallizes in large, shining, colorless plates, having
the disagreeable odor of naphthylamin. It is a weak base, and its
salts are decomposed by boiling water. Its aqueous solution, acidu-
lated with HC1, is colored rose -red by KNO2. By fusion with KHO
it yields anilin. It gives the "pine-shaving reaction" (p. 455). It
forms a compound, crystallizing in red needles, with picric acid.

Indole Homologues Derivatives of indole are produced by
substitution either in the benzene or in the pyrrole ring. The posi-
tions are distinguished as Bz. 1, 2, 3, 4 and Py.w, , and ft (see
formula p. 463). The alkyl indoles, the superior homologues of
indole, are formed: (1) by heating anilin with compounds containing
the group CO.CH2C1. Thus chloracetone and anilin yield - methyl-



CONDENSED HETEROCYCLIC COMPOUNDS 465



indole :

(2) by heating the phenylhydrazones (p. 429) of the ketones, alde-
hydes or ketone acids with ZnCl2. Thus w, a-dimethylindole is
obtained from acetone - phenyl- methyl - hydrazone :



The best known alkyl indoles are those in which the alkyl group
is in the pyrrole ring. They dissolve in concentrated acids, and are
precipitated unaltered from the solutions by dilution with water.
Fused with KHO, they yield potassium salts of indole- carboxylic
acids. Their hydrogen may be replaced by acidyls or by the diazo
group. They give the "pine-shaving reaction," and form red,
crystalline compounds with picric acid.

)8-Methyl-indole Skatole CeH^H^^CH exists in fa>ces,

in which it exceeds the indole in amount. It is formed during putre-
faction of the proteins, or by the action upon them of KHO in
fusion; also by the reduction of indigo. It is best obtained syntheti-
cally by heating propidene - phenylhydrazone with zinc chlorid :

C6H 5 .NH.N:CH.CH 2 .CH3 = C 6 H4< N ( H^)CH+NH3. It crystallizes
in brilliant plates; f.p. 95 (203 F.); insoluble in water, soluble in
alcohol and in ether; distils with vapor of water; has a strong faecal
odor. Its solution in concentrated HC1 is violet. Its H2SO4 solution
is colored deep purple when heated. Skatole, like indole, is in part
reabsorbed from the intestine, and appears in the urine, combined
with sulfuric and glucuronic acids.

/3-Methyl-indole-a-carboxylic Acid CeH^NH 5 !^ - 00011 f -P-
165; is a product of putrefaction, and also occurs in normal urine.
It produces an intense violet color with HC1 and dilute Fe2Cle solu-

tion. Skatole-acetic acid C 3 H 4 ^NH^^ C - CH 2.COOH is also pro-
duced during putrefaction.

Iso-indole (formula, p. 463) is formed by the action of alco-
holic ammonia upon brom-acetophenone (p. 400). It crystallizes in
colorless, silky plates; f. p. 195; insoluble in water, soluble in
alcohol, ether and benzene.

Indoxyl - Oxy indole C 6 H 4 <^HJ^ CH - not to be con '
founded with oxindole (p. 466), is a phenolic derivative of indole,
obtained from indigo -blue by fusion with KHO without contact of
air; or from its a -carboxylic acid, indoxylic acid. It is a very
unstable, oily substance, soluble in water, and readily oxidized to
indigo-blue (below). It readily combines with sulfuric acid or the



sulfates to form indoxyl-sulfuric acid, C 6 H 4 <T ; ^ \ , which is



C O S:0 2

; ^ \

NH CH OH



30



466 MANUAL OF CHEMISTRY

the uroxanthm, or urinary indican, existing in the urine, and formed
from indole. Acids decompose it, with formation of indoxyl, which
is converted into indigo -blue by Fe2Cle (see Urine).

Oxindole CcH^^n/CO ^ e lactam of o-amido-phenyl acetic
acid (p. 424), is obtained from dioxindole by reduction with sodium
amalgam in acid solution; or by reduction of o-nitrophenyl- acetic
acid. It crystallizes in easily soluble, colorless needles; f . p. 120.
In moist air it oxidizes to dioxindole. It reduces ammoniacal silver
nitrate solution. It combines with acids and bases.

Dioxindole Hydrindic Acid CeE^^^^^CO is the lactam

o-amido-mandelic acid (p. 424), and is formed by the action of Na
on isatin suspended in water. It forms yellow prisms, soluble in
water, and combines with acids and bases.

Isatin C6H 4 \^g/CO the lactam of o-amido-benzoyl- formic
acid (p. 424), is formed by oxidation of indigo -blue by HNOs; by
oxidation of oxindole or of dioxindole; and by other methods. It crys-
tallizes in shining, transparent, red-brown prisms, odorless, sparingly
soluble in water, readily soluble in alcohol. On further oxidation it

/CO
yields isatoic acid, CeH^ I. . With hydroxylamin it forms isa-

N.COOH
y C=NOH
toxim, CeH^ .\ , which is also formed by the action of nitrous

JN -^ OvyJti.

acid upon oxindole.

Indigo - blue IndigotinC 6 H4^NH/ c : C \NH/ C 6 H 4 constitutes
the greater part of commercial indigo. It does not exist preformed
in nature, but many plants, particularly Indigotifera tinctoria and
Isatis tinctoria, contain a yellow glucosid, indican (p. 413), which
on heating with dilate acids, or probably by enzymic action on ex-
posure to air in presence of water, is decomposed into a sugar and
indigo -blue. Commercial indigo contains 20 to 90 per cent, of
indigo-blue, which may be separated, nearly pure, by cautious sub-
limation. It is formed in several reactions, e.g., by oxidation of
indoxyl by Fe2Cle and HC1; from o-nitro-cinnamic acid by two
methods; by fusing phenyl-glycocoll (p. 424) with KHO; or by
heating o-nitro-acetophenone (p. 400) with zinc dust. It forms
purple -red, metallic, shining prisms or plates, odorless, tasteless,
neutral, soluble in hot anilin, hot oil of turpentine, and melted
paraffin, insoluble in the usual solvents. When heated it is in
part converted into a dark red vapor, and partly decomposed into
anilin and other products. In the presence of aqueous alkaline
solutions, reducing agents convert indigo-blue into indigo-white,

or di-indoxyl, CoR^^C c^C 6 H 4 , which dissolves in the



CONDENSED HETEROCYCLIC COMPOUNDS 467

alkali. This substance absorbs oxygen from the air rapidly, with
regeneration of indigo -blue. In absence of air it may be precipitated
from its alkaline solution by HC1, as a white, crystalline powder,
insoluble in water, but soluble in alcohol and ether, forming yellow
solutions. When oxidized, as by warming with dilute HNOa, indigo-
blue is converted into isatin, whose dilute solutions are also yellow.
Hence the decoloration of indigo -blue solution is utilized as a test
both for oxidizing (HNOa) and for reducing ( Mulder -Neubauer test
for glucose) substances.

Indigo-sulfonic Acids. Indigo -blue dissolves slowly in concen-
trated sulfuric acid, to a green solution, from which water precipitates
a blue powder, soluble in water, but insoluble in dilute acids. This
is indigo-monosulfonic or phoenicin-sulfonic acid, CieHg^C^.SOsH,
which forms purple-red salts, soluble in water. With fuming (Nord-
hausen) sulfuric acid, indigo-disulfonic, sulfindylic, or sulfindigotic
acid, CieHg^CMSOsHh, is formed, whose K and Na salts are also
soluble in water, and are met with in commerce as pastes called
indigo-carmine.

Dibenzo-pyrrole Diphenyl-imid Carbazole (formula p. 463)
exists in crude anthracene, and is formed by passing diphenylamin
through a red-hot tube, and from other diphenyl derivatives. It
is a crystalline solid; f . p. 238; soluble in alcohol and in toluene.
It is a weak base, gives the pine -shaving reaction, and the blue color
with isatin and H.2S04, and forms a picrate fusible at 182.



QUINOLIN AND ISO-QUINOLIN AND THEIR DERIVATIVES.

The quinolin, or benzo-pyridin bases accompany the pyridin
bases (p. 459) in bone-oil, and like those substances, are closely
related to the vegetable alkaloids. Quinolin, the parent substance of
the group, was first obtained by distilling quinin and cinchonin with
lime.

Chemically the quinolins are also related to the naphthalenes
(p. 452), and are formed by similar synthetic methods. Thus
quinolin is formed from allyl-anilin : C 6 H 5 .NH.CH 2 .CH:CH 2 =

C6H4\cH:CH+ 2H2 ' i n tne same manner as naphthalene is formed
from phenyl-butylene (p. 440). Quinolin and its derivatives may
also be produced synthetically : (1) From o-amido-benzenic com-
pounds containing an oxygen atom in the second lateral chain.
Thus o-amido-benzoic aldehyde and acetone yield a-methyl- quinolin:



N l . + 2HiO. (2) By heat-
ing the anilins with glycerol and H2SO4, in presence of an oxidizing



I
468 MANUAL OF CHEMISTRY

agent, such as nitro-benzene : C 6 H 5 .NH 2 H-CH 2 OH.CHOH.CH 2 OH=

,CH:CH

C6H/ I +3H 2 O+H 2 . (3) By the action of aldehydes upon
N iCH

anilins in presence of H 2 SO4 or HC1. Thus a- methyl -quinolin is ob-
tained from anilin and acetic aldehyde : C6H 5 .NH 2 -h2CHO.CH3=
,CH:CH



The quinolin bases are liquids of penetrating odor, sparingly sol-
uble in water, readily soluble in alcohol and in ether. They are
strong triacid bases, and form salts and ammonium-like compounds.
/CH:CH

Quinolin C 6 H 4 \ I is a mobile liquid ; b. p. 238 (460.4

N iCH

F.); becoming rapidly brown on exposure to air; has an intensely
acrid and bitter taste, and an odor somewhat like that of bitter
almonds; sparingly soluble in water, readily soluble in alcohol and
ether. Its dichromate crystallizes in yellow needles ; f. p. 165; very
sparingly soluble in water.

Quinolin Homologues Quinolin is the nucleus of a vast number
of products of substitution, among which are many isomeres, due to
differences in orientation, according as the substitution occurs in the
o-, m-, or p- position in the benzene ring, or in the a, ft, or y posi-
tion in the pyridin ring (see formula, p. 463). Thus there are seven
methyl-quinolins, or lepidins, etc.

Quinolin is of medical interest chiefly in connection with the vege-
table alkaloids of which it is the nucleus (p. 478). Certain synthetic
basic substances containing the quinolin nucleus have also been used
in medicine, in saline combination, as antiperiodics and antipyretics.
Among these are thallin, ethyl-thallin and kairin.

y CH:CH

a-Oxyquinolin Carbostyril CelLiy I is the lactam of

X N :C.OH

o-amido-cinnamic acid, formed by reduction of o-nitro-cinnamic ester.



Iso- quinolin CeH I differs from quinolin in that the

attachment of the benzene and the pyridin rings is by the ft and 7 po-
sitions of the latter in iso- quinolin, and by the a and ft positions in
quinolin (see formulae, p. 463). It accompanies quinolin in coal-tar,
and is the nucleus of the opium alkaloids (p. 483). It resembles
quinolin in its properties. F. p. 23; b. p. 240.5.

Hydroquinolins. Compounds corresponding to dihydroquinolins
are known. Tetrahydroquinolins are formed, by hydration of the
pyridin ring, by the action of nascent hydrogen on quinolius. Deca-
hydroquinolin, Co His N, corresponding to piperidin (p. 461), is
formed by heating quinolin with hydriodic acid and phosphorus.



PHENYL-PYEIDYL, DIPYRIDYL COMPOUNDS, ETC. 469



C. PHENYL-PYRIDYL, DIPYRIDYL, AND PYRIDYL-
PYRROLE COMPOUNDS.

These compounds (p. 453) contain two nuclei, one at least hetero-
cyclic, united together by loss of two hydrogen atoms.

Phenyl-pyridyls, or phenyl-pyridins (p. 461) consist of one or
more phenyl groups substituted in pyridin, 7-Phenyl-pyridyl,

N \CH-CH^ C ~ C \CH-CH/ CH as wel1 as the a and P compounds,
and diphenyl- and tetraphenyl-pyridins, are known.

y, y-Dipyridyl-N<^I^>C-C<^zi>-is formed by the

action of sodium upon pyridin. It forms colorless needles; f. p.
114; which yield isonicotinic acid (p. 461) on oxidation. The - ft
and ft -ft dipyridyls are formed by oxidation of the phenanthrolins,
and both yield nicotinic acid on oxidation. A fourth, probably a -a,
is formed by passing vapor of pyridin through a red-hot tube. The
dipyridyls take up nascent hydrogen to form substances, CioHi4N2,
isomeric with nicotin, and resembling that alkaloid (p. 473) closely
in chemical properties and in physiological action. The one obtained
from ft- ft dipyridyl is a very soluble and highly poisonous liquid,
called nicotidin. That from 7-7 dipyridyl is a crystalline solid, sol-
uble in water, less actively poisonous than nicotin, and called iso-
nicotin.

The pyridyl-pyrroles are formed by union of a pyridin and a
pyrrole ring, as the dipyridins are formed by union of two pyridin

y CH=CH v ^CH NH

rings. a- Pyridin -^-pyrrole, HC^ iC C\ I , consti-

^CH N^ X CH=CH

tutes the nucleus of nicotin (p. 474). It is a crystalline solid;
f. p. 72.

ALKALOIDS.

Until the constitution of all the substances grouped under this
term shall have been determined, the limitations of the application of
the name can be only provisional. It was first applied to the few
alkali -like substances first obtained from vegetable products, the
vegetable bases morphin, narcotin, veratrin, strychnin. Afterwards
its application was extended, and at the same time made more precise,
to include organic, nitrogenized substances, alkaline in reaction, and
capable of combining with acids to form salts in the same way as does
ammonia. This limitation is, however, too broad, as it classes the
aliphatic amins, and other similar bodies, with the true alkaloids,
which are cyclic. All substances generally classed as alkaloids, whose



470 MANUAL OF CHEMISTRY

constitution has been determined, contain at least one nitrogen-
containing heterocyclic ring, except theobromin and caffein, which
are not true alkaloids, but purin bases (p. 358). Almost all alka-
loids of known constitution contain the pyridin ring, more or less
modified by hydrogen at ion, either alone or in quinolin or isoquinolin.
Therefore, until recently, alkaloids were considered to be: basic sub-
stances containing the pyridin ring. But the hygrins, alkaloids
existing in coca leaves, are derivatives, not of pyridin, but of pyr-
rolidin (p. 456), a five-membered nucleus. So far as is now known,
no alkaloid contains more than one nitrogen atom in one and the same
ring. Therefore, provisionally, it may be stated that the alkaloids
are basic substances derived from heterocyclic nuclei containing but
one nitrogen atom in each nucleus. Under this definition pyridin
and quinolin and their homologues are alkaloids, as well as indole,
and other basic pyrrole compounds.

Some of the alkaloids, nicotin, conim, spartem and arecolin are
liquid, volatile, and contain C, N and H. Most of them, to the num-
ber of more than a hundred, are solid, crystalline, only partially
volatile without decomposition, if at all, and contain C, N, H and O.
Most of the alkaloids are very sparingly soluble in water, although
some are readily soluble; but soluble in alcohol, ether, petroleum-
ether, chloroform, benzene or amylic alcohol. Their salts, on the
other hand, are, for the most part, soluble in water, but insoluble in
the other solvents mentioned, except alcohol, in which they are
soluble. They are laevogyrous, except quinidin, cinchonin, conim,
narcotin and pilocarpin, which are dextrogyrous. Usually their
rotary power is diminished by combination with acids, although with
quinin the reverse is the case. Free narcotin is laevogyrous, its
salts are dextrogyrous. Most of the alkaloids are bitter in taste, and
alkaline in reaction.

The naming of the salts of the alkaloids has been the subject of
no little discussion. In obedience to the rules of orthography
adopted (see Appendix) the names of the alkaloids are made to
terminate in in, although in non-chemical writings the termination
ine is still usual, and the older termination ia is occasionally met
with. As most of the alkaloids are tertiary amins and some second-
ary amins, they combine with acids in the same manner that ammonia
does, that is, without elimination of water or of hydrogen, and by
change of the nitrogen valence from trivalent to quinquivalent:



2H 3 : N+H 2 S0 4 =(H 3 1

Ammonia. Sulfuric acid. Ammonium sulfate.

2[(Ci 7 H 19 3 ) i N]+H 2 S0 4 =[(C 17 H 19 3 ) KO
Morphia. Sulfnric acid. Morphium sulfate.



ALKALOIDS 471

Therefore these salts do not contain morphin, CnHigOsN'", as a sub-
stitute for the hydrogen of the acid, but the hypothetical morphium
(CuH^oOaN^ 7 , as the ammoniacal salts are not salts of ammonia, NHs,
but of ammonium, NEU. The compounds formed by the union of mor-
phin and other alkaloids with the hydracids, HC1, HBr, HI, may
properly and conveniently be referred to as morphin hydrochlorid (not
hydrochlorate) hydrobromid, hydroiodid, etc., they being considered,
not as salts of those acids, but as compounds in which one of the
valences of the quinquivalent nitrogen atom is satisfied by hydrogen
and another by chlorin.

Many of the alkaloids behave like esters, and are hydrolyzed by
baryta or the caustic alkalies, or by mineral acids, into two com-
ponents, one a base, the other an acid, the latter usually cyclic and
nitrogenous. On the other hand, concentrated HC1 removes EbO
from those alkaloids containing more than one hydroxyl, converting
them into apo-alkaloids, as morphin is converted into apomorphin.
Other alkaloids, containing methoxyl groups (OCHs), when acted
upon by concentrated HC1, are modified by replacement of OH for
the methoxyl groups. Reducing agents form hydro -bases, as piper-
idin is derived from pyridin. Distillation with zinc -dust causes
removal of the lateral chains from the oxygen-containing alkaloids,
with liberation of pyridin or quinolin. Oxidizing agents form car-
boxylic acids, or decompose the alkaloid into an acid and a base, or
cause the union of two molecules of the alkaloid with loss of
hydrogen .

Separation of Alkaloids from Organic Mixtures. The separation
of an alkaloid from an organic mixture (contents of stomach, viscera,
etc.) in a condition of puritj r sufficient to permit of its identification,
is one of the most difficult tasks of the toxicologist, and not to be
attempted in a case liable to be the subject of legal inquiry except by
one thoroughly competent. The processes usually followed are modi-
fications of that originally used by Stas, of which the most exhaus-
tive is the method of Dragendorff. They depend upon differences in
the solubilities of the several alkaloids and of their salts in water or
alcohol, and in various solvents immiscible with water. The alkaloid
is first extracted as a tartrate, sulfate or hydrochlorid by water or
alcohol, acidulated with the appropriate acid, and the extract purified
to a clear, acid, watery solution. This acid solution is then succes-
sively shaken with the immiscible solvents, such as ether, petroleum-
ether, benzene, chloroform, amylic alcohol and acetic ether, the
solvents being separated from the aqueous solution, and each evap-
orated by itself. During this treatment the alkaloids are held in the
aqueous solution, while the other solvents extract impurities and
certain glucosidal and acid poisons. The watery solution is now



472 MANUAL OF CHEMISTRY

rendered alkaline, which causes liberation of the alkaloid from its
saline combination, and is again successively agitated with the im-
miscible solvents named, they being each individually separated from
the aqueous liquid and evaporated. Each solvent extracts those
alkaloids which it is capable of dissolving, and they are sought for
by the suitable tests in the appropriate residues. Thus strychnin is
extracted by benzene, and morphin by amylic alcohol. The details
of the process, which are quite elaborate, must be carefully observed,
and the student is referred to special treatises upon the subject.

General Reactions of the Alkaloids. A great number of
"general reagents" for alkaloids have been suggested, of which only
the more important can be here mentioned:

Potash, soda, ammonia, lime, baryta and magnesia precipitate the



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