Part 23

2. _a._ The powder, or (with 'conia and nicotia') concentrated liquor, is treated with a drop or two of concentrated sulphuric acid:--A red colour is produced; probable presence of Brucia, Nicotina, Salicine, or Veratria. If the reddened mixture has at first a roseate hue, turning deep red on the addition of nitric acid, it is BRUCIA; if the original substance moistened with solution of potassa evolves the odour of tobacco, it contains NICOTINE; if the red colour produced by the acid is permanent and of an intense blood-hue, and the powder agglutinates into lumps like resin, it is SALICINE; if the colour is at first yellowish, changing to blood-red, and ultimately to crimson and violet, it is VERATRIA.

_b._ If instead of the substance being 'reddened' by strong sulphuric acid, no particular action ensues in the cold, it contains either Conia or Strychnia; if a small fragment of bichromate of potassa being now dropped in, produces a rich violet colour, it is STRYCHNIA; if the original matter on being heated, or treated with solution of potassa, evolves a penetrating, disagreeable odour, somewhat analogous to that from 'hemlock,' or to a mixture of those from tobacco and mice, it is CONIA.

"_Reactions with ceroso-ceric oxide._ This oxide exhibits characteristic colours with several alkaloids, especially with STRYCHNINE. When strong sulphuric acid is poured upon strychnine, and then a small quantity of ceroso-ceric oxide added, a fine blue colour is produced, similar to that which strychnine exhibits with potassium bichromate, but much more permanent. The blue colour gradually changes to cherry-red, and then remains unaltered for several days. This reaction is capable of detecting one part of strychnine in a million parts of liquid. BRUCINE similarly treated acquires an orange-colour, gradually changing to yellow; MORPHINE, olive-brown, finally brown; NARCOTINE, brown cherry red, finally wine-red; CODEINE, olive-green, finally brown; QUININE, pale-yellow; CINCHONINE and THEINE remain colourless; VERATRINE becomes reddish-brown; ATROPINE, dingy yellowish-brown; SOLANINE, yellow at first, finally brownish; EMETINE, brown; COLCHICINE, first green, then dirty brown; ANILINE, after a long time, acquires a blue colour extending from the edges inwards; CONINE becomes light-yellow. PIPERINE colours the sulphuric acid blood-red, and is turned dark-brown, almost black by the cerium oxide" (Sonnenschein).

"_Reactions with picric acid._ This acid is a very good precipitant for alkaloids, affording a very delicate test for many of them, and may perhaps also serve for separating them one from another. The precipitation takes place even in solutions containing a large excess of sulphuric acid, and is sometimes complete. _Precipitated_ are, BRUCINE, STRYCHNINE, VERATRINE, QUINIDINE, CINCHONINE, and most of the opium alkaloids; _not precipitated_, MORPHINE, ATROPINE (English), PSEUDO-MORPHINE, CAFFEINE, and all glucosides" (Hager).

The presence of one or more of the alkaloids being shown by any of the preceding methods, a portion of the original clear solution or powder, or of the precipitates or filtrates above referred to, must be treated with their characteristic tests, as given under the individual notices of these articles, so as to set at rest all doubt as to their identity. No single test must ever be relied on as a positive proof. The presence of Brucia, Morphia and Strychnia may be determined in substances which after being mixed with the salts of these alkaloids have undergone the acetous, vinous, or putrefactive fermentation, as shown by Orfila, MM. Larocque and Thibierge, and many other eminent chemists and toxicologists, and confirmed, in numerous cases, by our own experiments. Opium and morphia may thus be readily detected in beer, wine, soup, and milk. A paper by Professor DRAGENDORF in the 'American Chemist' for April, 1876, may be consulted with advantage.

_Concluding Remarks._ It is a singular fact that none of the organic bases found in plants have yet been formed artificially, although several analogous substances have been thus produced. Closely allied to the alkaloids there also exists an extensive series of neutral proximate principles, which differ from those substances chiefly in the absence of basic properties, and in most of them being destitute of nitrogen. They are usually bitter, and, like the alkaloids, generally represent the active properties of the plants in which they are found; whilst some of them possess considerable medicinal energy. Of this kind are asparagin, elaterin, gentianin, picrotoxin, salicin, &c. These two classes of bodies, though actually distinct, are frequently confounded. See ALKALI, ORGANIC BASES, POISONS, PROXIMATE PRINCIPLES, VEGETABLES, NOMENCLATURE, &c.; also the individual alkaloids under their respective heads.

=ALKALOIDS OF ACONITE=. The nature of the active principle of aconite root does not appear to have been satisfactorily determined. Messrs Groves, Wright, and Williams contend that the _Aconitum napellus_ yields an active crystalline alkaloid, which they distinguish as _Aconitine_, and to which they assign the formula C_{33}H_{43}NO_{12}; they add that additionally the root contains more or less of another active alkaloid, which they term _Pseudaconitine_, and which is represented by the formula C_{36}H_{49}NO_{11}; they also assert that the extract of the roots contains varying quantities of certain decomposition products resulting from the saponification of the above bases by the acids, which are produced by the breaking up of part of the aconitine. The name of these decomposition products is _Aconine_ and _Pseudaconine_. Of _Aconitum ferox_ they report that it yields a comparatively large quantity of _Pseudaconitine_ and a small quantity of _Aconitine_. They further affirm that the so-called aconitine of commerce is a mixture of true aconitine and pseudaconitine with variable quantities of their alteration products, aconine and pseudaconine, and of certain amorphous unnamed alkaloids.

Messrs Paul and Kingzett contest the accuracy of these deductions, and dispute the correctness of the formula given to aconitine. Dr Paul doubts whether the alkaloid to which the active properties of the root are ascribed has ever yet been obtained in an isolated condition. He thinks it probable that the substance obtained from aconite root was to a great extent a salt of an acid, like aconitic acid. For further information the reader is referred to the 'Pharmaceutical Year Book' for 1873, 1874, 1875, 1876, and 1877.

=AL'KANET.= _Syn._ ANCHU'SA, L.; ORCANETTE, Fr.; ORKANET, Ger.; OR'CHANET*, DYER'S AL'KANET, D. BU'GLOSS*. The _anchu'sa tincto''ria_ (Willd.; _lithosper'mum tincto''rium_--Linn.), a deciduous herbaceous plant, with a perennial, dark blood-red root. _Hab._ Asia Minor, Greece, Hungary, &c. It is also largely cultivated in the neighbourhood of Montpellier. The dried root (ALKANET ROOT; RADIX ANCHUSÆ, R. A. TINCTORIÆ) is chiefly imported from the Levant. It contains a beautiful blood-red colour, which it freely gives out to oils, fats, wax, spirits, essences, and similar substances, by simply infusing it in them, and is consequently much employed to colour these articles. Wax tinged with it, and applied on warm marble, stains it of a rich flesh-colour, which sinks deep into the stone, and possesses considerable durability. Its spirituous tincture also imparts a deep red to marble.

_Prop._, _&c._ The colouring matter of alkanet was regarded by Pelletier as a fatty acid (ANCHUSIC ACID); but it has since been shown to be a species of resin (ANCHUSINE, PSEUDO-ALKANNINE, P.-ALKANIUM). According to Dr John, good alkanet root contains 5-1/2 per cent. of this substance. Anchusine melts at 140° Fahr.; is scarcely soluble in water, to which it only imparts a dirty red colour, but is very soluble in alcohol, oils, and acetic acid. Alkalies turn it blue. It is found wholly in the root-bark. In selecting this article, the smaller roots should therefore be chosen, as they possess more bark than the larger ones, in proportion to their weight. Exposure to ammoniacal fumes, or even handling it much with the fingers, changes its red to a crimson or purplish hue.

_Uses_, _&c._ It is much employed by druggists and perfumers to colour oils, lip-salves, plasters, pomatums, &c.; by varnish-makers, to tinge their varnishes and lacquers; by statuaries to stain marble; by dairy-farmers, to colour cheese; by wine-merchants and bottlers (in the form of tincture), to stain beforehand the corks of their port-wine bottles, in order to imitate the effects of age, and as colouring and flavouring for factitious port wine; and by dyers, and others. A species of crimson rouge was formerly prepared from it (hence its name).

=ALLANTO'IC ACID.= See ALLANTOIN.

=ALLAN'TOIN.= C_{8}H_{6}O_{6}N_{4}. _Syn._ ALLANTO'IC ACID*, AMNIOT'IC A.[dagger] AM'NIC A.[dagger]; ALLANTOÏ'NA, L. A substance discovered by Vauquelin and Buniva in what they imagined to be the liquor amnii of the cow, and hence named by them amniotic acid. It was afterwards shown by Dzondi and Lassaigne to exist in the fluid of the allantoïs, and not of the amnios. It has since been produced artificially by Wöhler and Liebig.

_Prep._ 1. The allantoïc fluid of the f[oe]tal calf is evaporated to 1-4th or 1-5th of its volume, and then set aside for some time. The crystals thus obtained are purified by re-solution, digestion with animal charcoal, and re-crystallisation.

2. (Wöhler and Liebig.) Uric acid, 1 part; is dissolved in water, 20 parts; and freshly precipitated and well-washed binoxide of lead is added to the solution until the colour ceases to change; the liquid is next filtered while hot, evaporated until a pellicle forms on the surface, and then set aside to crystallise; the crystals being purified as before.

_Prop., &c._ Small, but very brilliant prismatic, transparent, colourless crystals; tasteless; neutral; soluble in 160 parts of cold water, and in much less at 212°; nitric acid converts it into ALLANTURIC ACID; oil of vitriol resolves it into ammonia, carbonic acid, and carbonic oxide; hot concentrated solutions of the caustic alkalies change it into ammonia and oxalic acid.

=ALLANTOX'ICUM.= [L.] _Syn._ ALLANTOX'ICUM, L. (prim., Gr.). The poison developed, during putrefaction, in sausages made of blood, liver, &c. "It often proves speedily fatal." (Kraus.)

=ALLGEMEINE FLUSSTINCTUR= (Sulzberger, Salzungen). For the relief of a number of diseases, among which are cholera and sea-sickness. Aloes, 1 part; spirit of wine, 2 parts. (Spau.)

=ALLIA'CEOUS= (-sh'us). _Syn._ ALLIA'CEUS, L.; ALLIACÉ, AILIACÉ, Fr.; KNOBLAUCHARTIG, &c., Ger. Garlick-like; an epithet applied to substances having the odour or properties of garlic or onions.

=Alliaceous Plants.= Chives, garlic, leeks, onions, rocambole, shallots, &c.

=ALLIGA'TION.= _Syn._ ALLIGA'TIO, L. In _commercial arithmetic_, a rule for ascertaining the price or value of mixtures, and for determining the proportions of the ingredients that must be taken to produce mixtures of any given price, value, or strength. The first is called ALLIGATION ME'DIAL; the second, ALLIGATION ALTERN'ATE. Its principles and applications are explained under MIXTURES (Arithmetic of).

=ALLOP'ATHY.= _Syn._ ALLOPA'THIA, L. (from [Greek: allos], _other_, _different_, and [Greek: pathos], _affection_ or _disease_, Gr.); ALLOPATHIE, Fr. In _medicine_, the method of curing disease by the use of remedies which tend to produce a condition of the system, either differing from, opposed to, or incompatible with the condition believed to be essential to the disease it is sought to cure. It is commonly employed to distinguish the ordinary system of medical practice from hom[oe]opathy (which see). Hence (an) ALLOP'ATHIST, and the corresponding adjective ALLOPATH'IC (_allopath'icus_, L.).

=ALLOT'ROPY.= _Syn._ ALLOT'ROPISM; ALLOTRO'PIA, ALLOTROPIS'MUS, L. Literally, a difference in character; another form of the same substance. In _chemistry_, a term invented, by Berzelius, to express the state or condition, or the change of character, assumed by certain substances at different temperatures, or under different treatment, whilst their nature and composition continue the same. It more particularly relates to colour, hardness, solubility, texture, &c. Boron, carbon, silicon, iron, sulphur, and phosphorus, afford striking examples of the changes here referred to.

=ALLOX'ANTIN.= C_{8}H_{4}N_{4}O_{7}.3H_{2}O. A crystallisable substance, first obtained by Dr Prout from uric acid.

_Prep._ 1. Uric acid, 1 part; is boiled in water, 32 parts; dilute nitric acid being added until solution is complete; the resulting liquid is evaporated to 2/3rds its volume, and then set aside for 10 or 12 hours; the crystals, which are deposited, are purified by re-solution and crystallisation.

2. Sulphuretted hydrogen gas is passed, in a full stream, through a moderately strong aqueous solution of alloxan, in the cold. The alloxantin, which is deposited as a crystalline mass, is purified by draining, cautious washing with cold water, re-solution in boiling water, and re-crystallisation. The impure mother-liquor from which crystals of alloxan have separated, if diluted with water, may be used for this purpose.

_Prop., &c._ Crystals, small colourless, transparent, four-sided, oblique rhombic prisms; scarcely soluble in cold water; solution reddens litmus; with baryta water it gives a characteristic violet-coloured precipitate, which disappears on heating; and with nitrate of silver a black precipitate of that metal; the crystals are reddened by ammoniacal vapours.

=ALLOY'.= _Syn._ ALLIAGE, Fr.; LEGIRUNG, VERMISCHUNG DURCH SCHMELZEN, Ger. In _coinage_, a compound of the precious metals with another, or others, of less value; also the least valuable metal, or metals, in such compounds. In _chemistry_ and _metallurgy_, combinations of the metals with each other usually obtained by fusion. When mercury is one of the component metals, the compound is termed an AMALGAM.

_Prep., &c._ No General rules can be given for this purpose. Alloys of metals differing greatly in fusibility, are commonly made by adding the more fusible one, either in the melted state, or in small portions at a time, to the other melted, or heated to the lowest possible temperature at which a perfect union will take place between them. The mixture is usually affected under a flux, or some material that will promote liquefaction, and prevent volatilisation and unnecessary exposure to the air. Thus, in melting lead and tin together, for solder, resin, or tallow is thrown upon the surface; in tinning copper, the surface is rubbed with sal ammoniac; and in combining some metals, powdered charcoal is used for the same purpose. Quicksilver combines with many metals in the cold, forming AMALGAMS.

_Comp._ The following _Table_ exhibits the composition of the more important compounds of this class:--

_Table of the principal Alloys._[27]

NAMES. COMBINING METALS.

ALBATA See German Silver. AMALGAMS Mercury and other metals. BATH-METAL Copper and zinc. BELL-METAL Copper and tin. BRASS Copper and zinc. BRITANNIA METAL Tin with antimony, copper, and bismuth. BRONZE Tin and copper. BRONZE ALUMINIUM Copper and aluminium. CANNON-METAL Tin and copper. DUTCH GOLD Copper and zinc. FUSIBLE METAL Bismuth, lead, and tin. GERMAN SILVER Copper, nickel, and zinc, with, sometimes, a little iron and tin. GOLD (_standard_) Gold with copper. GOLD (_old standard_) Gold with copper and silver. GUN-METAL See Cannon-metal. MOSAIC GOLD Copper and zinc. OR-MOLU Copper and zinc. PEWTER (_common_) Tin and lead. PEWTER (_best_) Tin with antimony, bismuth and copper. POT-METAL, COCK-METAL Copper and lead, with, sometimes, a little zinc. QUEEN'S METAL Tin with antimony, bismuth, and copper. SHOT-METAL Lead with a little arsenic. SILVER (_standard_) Silver and copper. SOLDER Tin and lead. SPECULUM-METAL Tin and copper, and arsenic. STEREOTYPE-METAL Lead, antimony, and bismuth. TOMBAC, RED TOMBAC Copper and zinc. TUTANIA See Britannia metal. TYPE-METAL Lead and antimony. WHITE COPPER (_Packfong_; Copper and arsenic. _Whitetombac_)

[Footnote 27: For the proportions of the component metals, refer to the alloys under their respective heads.]

_Prop., &c._ Alloys generally possess characteristics unshared by their component metals. Thus, copper and zinc form brass, which has a different density, hardness, and colour to either of its constituents. Whether the metals tend to unite in atomic proportions, or in any definite ratio, is still undetermined. The evidence afforded by the natural alloys of gold and silver, and by the phenomena accompanying the cooling of several alloys from the state of fusion, goes far to prove that such is the case. (Rudberg.) The subject is, however, one of considerable difficulty, as metals and metallic compounds are generally soluble in each other, and unite by a simple fusion and contact. That they do not combine indifferently with each other, but exercise a species of elective affinity not dissimilar to other bodies, is clearly shown by the homogeneity and superior quality of many alloys in which the constituent metals are in atomic proportions. The variation of the specific gravity and melting-points of alloys from the mean of those of their component metals, also affords strong evidence of a chemical change having taken place. Thus, alloys generally melt at lower temperatures than those required for their separate metals. They also usually possess more tenacity and hardness than the mean of their constituents.

Matthiessen found that when weights are suspend to spirals of hard-drawn wire made of copper, silver, gold, or platinum, they become nearly straightened when stretched by a moderate weight; but wires of equal dimensions composed of copper-tin (12% of tin), silver-platinum (36% of platinum), and gold-copper (84% of copper), scarcely undergo any permanent change in form when subjected to tension by the same weight.

The same chemist gives the following approximative results upon the tenacity of certain metals and wires hard drawn through the same gauge (No. 23):

Breaking strain for:

lbs. Copper 25-30 Tin under 7 Lead " 7 Tin-lead (20% lead) about 7 Tin-copper (12% copper) " 7 Copper-tin (12% tin) " 80-90 Gold 20-25 Gold-copper (8·4% copper) 70-75 Silver 45-50 Platinum 45-50 Silver-platinum (30% platinum) 75-80

On the other hand, their malleability, ductility, and power of resisting oxygen is generally diminished. The alloy formed of two brittle metals is always brittle; that of a brittle and a ductile metal, generally so; and even two ductile metals sometimes unite to form a brittle compound. The alloys formed of metals having different fusing-points are usually malleable whilst cold, and brittle whilst hot. The action of the air on alloys is generally less than on their simple metals, unless the former are heated. A mixture of 1 part of tin and 3 parts of lead is scarcely acted on at common temperatures; but at a red heat it readily takes fire, and continues to burn for some time like a piece of bad turf. In like manner, a mixture of tin and zinc, when strongly heated, decomposes both moist air and steam with almost fearful rapidity.

The specific gravity of alloys is never the arithmetical mean of that of their constituents, as commonly taught; and in many cases considerable condensation or expansion occurs. When there is a strong affinity between two metals, the density of their alloy is generally greater than the calculated mean; and _vice versâ_, as may be seen in the following Table:--

_Alloys having a density_--

Greater than the mean of Less than the mean their constituents:-- of their constituents:--

Copper and bismuth, Gold and copper, " palladium, " iridium, " tin, " iron, " zinc, " lead, Gold and antimony, " nickel, " bismuth, " silver, " cobalt, Iron and antimony, " tin, " bismuth, " zinc, " lead, Lead and antimony, Nickel and arsenic, Palladium and bismuth, Silver and copper, Platinum and molybdenum, Tin and antimony, Silver and antimony, " lead, " bismuth, " palladium, " lead, Zinc and antimony. " tin, " zinc.

"Every alloy," says Dr Ure, "is, in reference to the arts and manufactures, a new metal, on account of its chemical and physical properties. A vast field here remains to be explored. Not above sixty alloys have been studied by chemists, out of many hundreds which may be made, and of these very few have yet been practically employed. Very slight modifications often constitute very valuable improvements upon metallic bodies." See ANALYSIS, ASSAYING, BRASS, BRONZE, ELECTROTYPE, GERMAN SILVER, GOLD, METALS, SPECIFIC GRAVITY, &c.

=ALL'SPICE.= See PIMENTO.

=ALLU''VIAL.= (-l'[=o][=o]v'-y[)a]l). _Syn._ ALLU''VIOUS*; ALLU''VIUS, L.; D'ALLUVION, Fr. In _geology_, applied to partial deposits of mud, sand, gravel, &c., left by rivers and floods upon land not permanently submerged beneath water; in _agriculture_, applied to soils so formed or deposited.

=ALLU''VIUM.= [L., Eng.] _Syn._ ALLUVION, Fr.; ANFLÖSSUNG, ANSCHWEMMUNG, Ger. In _geol._ and _agr._, alluvial deposit or soil. See SOILS, &c.

=AL'LYL= (-l[)i]l). C_{3}H_{5}. In _chemistry_, the radical of the essential oils containing sulphur, as those of assaf[oe]tida, garlic, horseradish, mustard, onions, &c., which are either sulphides or sulphocyanides of allyl. Its probable existence was first shown by Captain Reynolds, who succeeded in producing several of its derivatives. It has since been obtained, in a separate state, by the action of sodium upon iodide of allyl. It is an oily substance with a high boiling point.

=Allyl, Sulphide of=, (C_{3}H_{5})_{2}S; obtained (artificially) by acting on sulphocyanide of allyl with sulphide of potassium. See OIL OF GARLICK.

=Allyl, Sulphocy'anide of=, C_{3}H_{5}CNS; obtained by submitting iodide of allyl to the action of sulphocyanide of potassium; or by gently heating a mixed alcoholic solution of sulphide of allyl and bichloride of mercury, with sulphocyanide of potassium. See OIL OF MUSTARD (VOLATILE).