Chapter C: W. HEATON, F.I.C., F.C.S., Lecturer on Chemistry at the (4)

The leaves should be gathered as soon as the flowers appear. The root should be taken up in autumn. When the whole plant is employed, it should be gathered as soon as the flowers begin to open. The strength (richness in aconitia) varies considerably with the time of the year. 1 oz. of the fresh root contains 1/4 to 3/4 gr. of aconitia; 1 lb. of the dried English root contains from 12 to 36 gr. (Herapath). The leaves possess the greatest activity just before flowering; the root, after it. The root is at all times fully six times as strong as the leaves or herb. The wild plant contains much more aconitia than that which is cultivated. The herb, and all its preparations, lose their efficacy if long kept. The powder, more particularly, cannot be relied on. Mr Holmes says it is difficult to find in a commercial sample of aconite root one root in a dozen, which upon fracture appears sound and in good condition.

_Properties, Antidotes, &c._ See ACONITE.

_Tests, &c._ See ACONITE.

_Uses, &c._ In small doses aconite is narcotic, powerfully diaphoretic, and sometimes diuretic; in larger ones, the symptoms are similar to those produced by aconitia. It acts as a powerful sedative on the heart's action, and destroys sensibility without disturbing the mental faculties. It has been given in chronic rheumatism, gout, paralysis, scirrhus, scrofula, cancers, venereal nodes, epilepsy, amaurosis, intermittents, &c.; but its exhibition requires the greatest possible caution. As a topical benumber it has been used with great advantage in painful affections depending on increased sensibility of the nerves. Externally it "is most valuable for the cure of neuralgic and rheumatic pains. In neuralgia, no remedy, I believe, will be found equal to it. One application of the tincture produces some amelioration; and after a few times' use, it frequently happens that the patient is cured. In some cases, the benefit appears almost magical. In others, however, it entirely fails to give permanent relief." "I do not think that in any (case) it proves injurious." "When it succeeds, it gives more or less relief at the first application. When the disease depends on inflammation, aconite will be found, I think, an unavailing remedy." "In rheumatic pains, unaccompanied with local swelling or redness, aconite is frequently of very great service." (Pereira, iii, 691.) _Dose_, of the powder, 1 to 2 gr., gradually increased to 6 or 8. Dr Stocrk was the first who gave wolfsbane internally, about the year 1762. It has since been successfully employed in Germany in cases of chronic rheumatism, gout, &c., some of which were of long standing and had resisted every other remedy. In England it has been less extensively used.

=Aconitum Panicula'tum.= Panicled wolfsbane; a species formerly ordered in the Ph. L.; and, with _a. napellus_, also in the Ph. U. S. It is less active than the officinal species.

=A'CORN.= _Syn._ GLANS. QUER'CUS, L. The seed or fruit of the oak. In the early ages of the world, acorns probably formed one of the principal articles of the food of man. (Ovid, _Met._, i, 106; Virgil, _Georg._, i, 8; &c.) In modern times, during periods of scarcity, they have been consumed as food on the Continent. Besides starch, they contain a peculiar species of sugar, which crystallises in prisms, and is unfermentable; they also contain tannic and gallic acids. Mannite and dulcose are the substances which it most nearly resembles. (M. Dessaignes.) During the autumn, acorns are said to be sometimes poisonous to cattle and sheep. Supposed cases of so-called acorn poisoning are best treated by withdrawing the supply of acorns, or removing the animals from the pastures on which the acorns fall, and by the administration of aperients, alkalies, and stimulants.

=AC'ORUS CAL'AMUS.= See SWEET FLAG.

=ACOTYLE'DONS= (-ko-te-l[=e]'-). _Syn._ ACOTYLE'DONES (d[)o]n-[=e]z; L., prim. Gr.), Jussieu; ACOTYLÉDONS, Fr.; OHNE SAMENLAPPEN, Ger. In _botany_, plants whose seeds are not furnished with distinct cotyledons or seed-lobes. _Acotyledonous plants_ form one of the two great divisions of the vegetable kingdom, according to the natural system. They are remarkable by increasing chiefly in length, by additions to their end; and not by addition to the outside, as in Exogens; nor to the inside, as in Endogens. They are also termed ASEX'UAL and FLOWERLESS PLANTS, and answer to the CRYPTOGAMIA of the Linnean system. See ACROGENS, CELLULARES, THALLOGENS, &c.

=ACOUS'TICS= (-kow'-). The science of audition and sound; that branch of physics which treats of their cause, nature, and phenomena. The doctrine of the production and transmission of sound is termed DIACOUS'TICS; that of reflected sound CATACOUS'TICS.

=Acoustics.= In _medicine_, remedies employed to relieve deafness. See DEAFNESS and DROPS, ACOUSTIC.

=ACQUETTA.= [IT., _Little Water._] _Syn._ AQUA TOFFANA; A. TOFFANIA; ACQUETTA DI NAPOLI DELLA TOFFANA, IT. A celebrated poison, prepared by an Italian woman named Toffano, or Tophana, and in great request in Rome about the middle of the 17th century. The composition of this poison has been a matter of frequent controversy. Pope Alexander VII, in his proclamation, described it as "aquafortis distilled into arsenic." This would produce a concentrated solution of arsenic acid. The Emperor Charles VI, who was governor of Naples during Toffano's trial, declared to his physician, Garelli, that it was arsenic (arsenious acid) dissolved in _aqua cymbalariá_. According to Gerarde this cymbalarià was an aquatic species of pennywort, highly poisonous. The only objection to the latter statement is the smallness of the dose, regard being had to the comparative insolubility of arsenious acid; but if the woman Toffano prepared two poisons, as is probable from history--one, a single dose of which was fatal, and another, of which the dose required repetition, and which was more gradual in its activity--the discrepancy will be at once removed.

=AC'RID.= _Syn._ AC'ER, AC'RIS, L.; ACRE (âcre), Fr.; BEISSEND, SCHARF, Ger. In _chemistry_ and _medicine_, sharp, pungent, acrimonious. Acrid substances are such as excite a sensation of pungency and heat when tasted, and which irritate and inflame the skin; as mustard, turpentine, cantharides, &c.

=ACRIDITY.= _Syn._ ACRETÉ, Fr.; ACRITUDO, L. The quality of being acrid.

=AC'RIMONY.= _Syn._ ACRIMO'NIA, L.; ACRIMONIÉ, ACRETÉ, Fr.; SCHARFE, Ger. In _medicine_ and _chemistry_, the quality or property of inflaming, irritating, corroding, dissolving, or destroying other bodies.

=ACROGENS.= _Syn._ ACROGENÆ, L.; ACROGÈNES, Fr. In _botany_, acotyledonous or cryptogamic plants, in which stems and leaves, or an organisation approaching leaves, are distinguishable; which have stomates or breathing spores on their surface, are propagated by spores, and increase by the growth of the stem at the point only. Ferns and club-mosses are examples of this class of plants.

=ACROLEIN.= _Syn._ ACRYLIC ALCOHOL. This substance occurs amongst the products of decomposition when glycerine or any of its compounds is subjected to ordinary distillation. It derives its name from its violently irritant effect upon the mucous membranes of the eyes and respiratory organs. It is best prepared by the process of Redtenbacher (see 'Leibig's Ann.,' xlvii, 114), by distilling in a capacious retort, a mixture of glycerine with phosphoric anhydride, or with hydric-potassic sulphate (the acid sulphate or bisulphate of potash); the vapours must be condensed in a properly cooled receiver, which is luted on to the retort and provided with a tube opening into a chimney having a good draught. The distilled liquid separates into two layers, the upper one consisting of acrolein, and the lower one of an aqueous solution of the same substance mixed with a quantity of acrylic acid. This distillate, after digestion with finely powdered litharge, with the object of neutralising the acid, must be rectified by the heat of a water bath: the acrolein so obtained must be submitted to a second rectification from calcic chloride. All these operations must be conducted in vessels filled with carbonic anhydride (carbonic acid) because acrolein becomes rapidly oxidized when exposed to the air.

Acrolein is a clear colourless liquid, lighter than water, boiling at about 125° F. It has great refracting power and a burning taste; when pure it is neutral to test paper.

=AC'ROSPIRE= (-spire). _Syn._ ACROSPI'RA, L.; PLUMULE, Fr.; BLATTKEIM, Ger. The shoot or sprout of a seed, when it begins to grow; the part of a germinating seed termed the plume, or plumula.

When the growth of a seed begins to be developed, the germ, from which the stem originates, shoots forth under the form of a delicate curved fibre, which, gradually bursting its covering, makes its appearance at the end of the seed. The fibrils of the radicle first sprout forth from the tip of the grain; a white elevation appears, that soon divides into three or more radicles, which rapidly grow larger, and are succeeded by the plumula, which peeps forth at the same point, in the form of a pale green leaflet, which, twisting thence beneath the husk to the other end of the seed, ultimately bursts its prison-house, and becomes a perfect leaf. See GERMINATION and MALTING.

=ACTINIC RAYS.= See ACTINISM.

=ACTINISM.= _Syn._ ACTINIC RAYS; CHEMICAL RAYS. A term given to a supposed principle accompanying the heat and light of the sunbeam. Actinic rays chiefly exist beyond the violet extremity of the solar spectrum, and are characterised by the power of exciting chemical change, _e.g._, the decomposition of certain silver salts (in photography); the combination of a mixture of chlorine and hydrogen, &c. The so-called vital functions of animals and plants are also greatly influenced by the actinic or chemical rays.

=ACTINOGRAPH.= An instrument for registering the intensity of the chemical influence (_actinism_) of the sun's rays.

=ACT, TOWNS IMPROVEMENT CLAUSES, 1847= (10 & 11 Vict., c. 34), The following provisions of this Act are incorporated in the Public Health Act, 1875, and refer exclusively to urban districts:--

1. With respect to naming the streets and numbering the houses.

2. With respect to improving the line of the streets and removing the obstructions.

3. With respect to ruinous or dangerous buildings.

4. With respect to precautions during the construction and repair of sewers, streets, and houses.

5. With respect to the regulation of slaughter houses.

Notices for alterations under the 69th, 70th, and 71st sections, directions under the 73rd section, and orders under the 74th section of the said Towns Improvement Clauses Act, may, at the option of the urban authority, be served on owners instead of occupiers, or on owners as well as occupiers, and the cost of works done under any of these sections may, when notices have been so served on owners, be recovered from owners instead of occupiers; and when such cost is recovered from occupiers, so much thereof may be deducted from the rent of the premises where the work is done as is allowed in the case of private rates under the Act.

=AC'TUAL.= Real, effectual, absolute; as opposed to that which is merely virtual or potential. In _surgery_, a red-hot iron, or any other heated body, used as a cautery, is termed the ACTUAL CAUTERY; whilst a caustic or escharotic so employed is called the POTENTIAL CAUTERY.

=ACTUAL CAUTERY.= See ACTUAL.

=ACUTE'.= _Syn._ ACUT'US, L.; AIGU, Fr.; HEFTIG, HITZIG, SPITZIG, Ger. Sharp, pointed, sensitive. Applied to the senses, as acute hearing, eyesight, &c. In _pathology_, diseases exhibiting violent symptoms, and whose course is short, are said to be acute diseases.

=ADAPTER.= In _chemistry_, a tube placed between two vessels (commonly a retort and receiver) for the purpose of uniting them or increasing the distance between them, so as to facilitate the condensation of vapour in distillation. (See _figure._)

=ADDER'S TONGUE.= _Syn._ COMMON ADDER'S TONGUE; OPHIOGLOS'SUM VULGA'TUM, Linn. A perennial plant, of the natural order Filices (DC.), growing wild in England. It is found in our woods and pastures, and flowers in May and June. It was once used to form a celebrated traumatic or vulnerary ointment and is still highly esteemed among rustic herbalists.

=ADEPS.= _Syn._ LARD. See ADEPS PRÆPARATUS, FAT, and LARD.

=ADEPS BENZOATUS.= _Syn._ BENZOATED LARD.

=ADEPS PRÆPARATUS.= _Syn._ AXUNGE; PREPARED LARD.

=ADHE'SION= (-h[=e]-zhün). _Syn._ ADHÆ'SIO, L.; ADHESION, Fr.; ANHÄNGUNG, ARXLEBUNG, Ger. The act or state of sticking or being united.

=Adhesion.= In _physics_, the force with which bodies remain attached to each other when brought into contact; _e.g._, ink adheres to paper, paint adheres to wood, &c. It differs from 'cohesion' in representing the force with which different bodies cling together; whereas cohesion is the force which unites the particles of a homogeneous body with each other, _e.g._, particles of iron cohere and form a mass of iron; particles of water cohere and form a mass of water, &c.

=Adhesion.= In _pathology_, the morbid union, from inflammation, of parts normally contiguous but not adherent.

=Adhesion.= In _surgery_, the reunion of divided parts, by the adhesive inflammation; as when incised wounds heal by what is termed the 'first intention.'

=ADHE'SIVE.= _Syn._ ADHÆSI'VUS, L.; ADHÉSIF, Fr.; ADHÄSIVE, VERWACHSEND, Ger. In _pharmacy_, &c., having the quality or property of sticking or adhering. Hence adhe'siveness.

=AD'IPOCERE= (-s[=e]re). _Syn._ GRAVE-WAX[double-dagger]; ADIPOCE''RA, L.; ADIPOCIRE, Fr.; FETEWACHS, Ger. A substance resembling a mixture of fat and wax, resulting from the decomposition of the flesh of animals in moist situations, or under water. It is chiefly margarate of ammonium. Lavoisier proposed to produce this substance artificially, for the purposes of the arts. Attempts have since been made to convert the dead bodies of cattle (carrion) into adipocere, for the purposes of the candle-maker and the soap-boiler, but without success. Besides, dead animal matter can be worked up more profitably than in making artificial adipocere.

Hatchettine or rock-fat is sometimes called 'adipocere'; and bog-butter is a substance nearly similar to it.

=AD'JECTIVE.= _Syn._ ADJECTI'VUS, L.; ADJECTIF, Fr. In _dyeing_, depending on another, or on something else; applied to those colours which require a base or mordant to render them permanent. See DYEING.

=AD'JUVANT.= [Eng., Fr.] _Syn._ AD'JUVANS, L.; AIDANT, &c., Fr. Assistant; helping. (As a substantive--) In _prescriptions_, see PRESCRIBING (Art of).

=ADULTERATION.= Strictly speaking, this term ought only to be applied to the practice of adding substances to articles of commerce, food or drink, for the purposes of deception or gain, but a wider interpretation is frequently placed on the word than the definition given by magistrates and analysts, these latter often regarding accidental impurity, or even, in some instances, actual substitution as acts of adulteration.

The following definition of an adulterated substance has been adopted by the Society of Public Analysts--

A substance shall be deemed to be adulterated--

A. _In the ease of food or drink:_

1. If it contain any ingredient which may render such article injurious to the health of a consumer.

2. If it contain any substance that sensibly increases its weight, bulk, or strength, or gives it a fictitious value, unless the amount of such substance present be due to circumstances necessarily appertaining to its collection or manufacture, or be necessary for its preservation, or unless the presence thereof be acknowledged at the time of sale.

3. If any important constituent has been wholly or in part abstracted or omitted, unless acknowledgment of such abstraction or omission be made at the time of sale.

4. If it be an imitation of or sold under the name of another article.

B. _In the case of drugs:_

1. If when retailed for medical purposes under a name recognised in the 'British Pharmacop[oe]ia' it be not equal in strength and purity to the standard laid down in that work.

2. If when sold under a name not recognised in the 'British Pharmacop[oe]ia' it differs materially from the standard laid down in approved works on materia medica, or the professed standard under which it is sold.

_Limits._ The following shall be deemed limits for the respective articles referred to:

_Milk_ shall contain not less than 9·0 per cent., by weight, of milk solids, not fat, and not less than 2·5 per cent. of butter fat.

_Skim Milk_ shall contain not less than 9·0 per cent. by weight, of milk solids not butter fat.

_Butter_ shall contain not less than 80 per cent. of butter fat.

_Tea_ shall not contain more than 8·0 per cent. of mineral matter, calculated on the tea dried at 100° C., of which at least 3·0 per cent. shall be soluble in water, and the tea as sold shall yield at least 30 per cent. of extract.

_Cocoa_ shall contain at least 20 per cent. of cocoa fat.

_Vinegar_ shall contain not less than 3 per cent. of acetic acid.

The practice of fraudulent adulteration has been indulged in for centuries. In every civilised state there have been enactments against it. The Romans had their inspectors of meat and corn. In England an Act to prohibit adulteration was passed as early as 1267, and penalties against it were in force in 1581, 1604, 1836, 1851. In 1822, Accum published a work having the sensational title of 'Death in the Pot,' and in 1855 appeared Dr Hassall's book, 'Food and its Adulterations.' The information conveyed in these works, added to the revelations of the 'Lancet' Sanitary Commission, and the contributions to scientific literature on the subject of food by Letheby, Pavy, Parkes, Blyth, and others, together with the published evidence given before the House of Commons Commission appointed to carry out an inquiry into the subject, roused public attention to such a degree as to lead to the passing by the legislature of the Adulteration Acts.

The sophistications may be divided into several distinct classes:

1. To give weight or volume, such as water added to butter, plaster of paris to flour, &c.; red earths to annatto, sand to tea-leaves, &c.; water to milk, &c.; all these, therefore, are substitutions of worthless or very cheap articles which take the place of the real.

2. To give a colour which either makes the article more pleasing to the eye, or else disguises an inferior one, _e.g._, Prussian blue, black lead, &c., to green teas; annatto to cheese, &c.; arsenite of copper to sweetmeats, &c.

3. Substitutions of a cheaper form of the article, or the same substance from which the strength has been extracted put in the place of the real, _e.g._, tea mixed with spent leaves, &c.

4. A very small class where the adulteration is really added with no fraudulent intent, but to enhance the quality of the goods sold--alum to bread in small quantities.

The following, according to Blyth ('Dic. of Hygiène'), is a list of articles most commonly adulterated, with the names of the substances used in their sophistication:--

ACONITIA with other alkaloids, _e.g._, delphinia, aconella, &c.
ALE, common salt, _Cocculus indicus_, grains of paradise, quassia,
and other bitters, sulphate of iron, alum, &c.
ALLSPICE, mustard husks.
ANCHOVIES, other fish, and colouring matters, _e.g._, Armenian
bole, Venetian red, &c.
ANNATTO, all sorts of starch, soap, red ferruginous earths,
carbonate and sulphate of lime, salts, &c.
ARROWROOT, various other fecula, such as sago, tapioca, potato,
and others.
BALSAM OF COPAIBA, turpentine and fixed oils.
BEEF (POTTED), Armenian bole.
BISMUTH, carbonate of lead, sometimes arsenic (this latter is an
impurity not intentional).
BLOATERS (POTTED), Armenian bole.
BRANDY, water, burnt sugar, &c.
BREAD, potatoes (mashed), alum, inferior flour, &c., &c.
BUTTER, water, salt, colouring matter, lard, tallow, and other
fats.
CAJUPUT OIL, copper, camphor dissolved in oil of rosemary, and
coloured with copper as a substitute.
CALAMINE, coloured sulphate of baryta.
CALOMEL, sulphate of baryta, chalk, white precipitate, white lead,
pipe-clay, &c., &c.
CALUMBA, tinged bryony root, root of _Frasera Walteri_, and
others.
CAMBOGE, starch, &c.
CAMPHOR, a substitution of Borneo camphor has been made.
CANTHARIDES, golden beetle, artificially coloured glass, &c.
CARBONATE OF LEAD, sulphate of baryta, sulphate of lead, chalk,
&c., &c.
CARMINE (COCHINEAL), sulphate of baryta, bone black, &c.
CASSIA (SENNA), leaves of _Solenostemma argel_, and other foreign
leaves.
CASTOR OIL, other oils, often small quantities of croton oil.
CAYENNE, ground rice, vermilion, Venetian red, turmeric.
CHAMPAGNE, gooseberry and other wines as substitutes, different
colouring matters, &c.
CHEESE, annatto, bole (Armenian), and other colouring matters.
CHICORY, colouring matters, such as ferruginous earths, and burnt
sugar, Venetian red, &c., and different flours, such as wheat,
rye, beans, &c., and sometimes sawdust.
CIDER, lead (as an impurity, not intentional).
CIGARS, substitutions of hay and other rubbish, inferior tobacco,
leaves sometimes darkened by some brown vegetable dye.
CINNAMON, cassia, clove stalks, and different flowers.
CLARET, brandy, and substitution of inferior wines.
CLOVES, clove stalks.
COCOA AND CHOCOLATE, cheaper kinds of arrow-root, such as _Tous
les mois_ and East Indian, animal matter, corn, sago, tapioca,
&c.
COFFEE, chicory, roasted wheat, rye flowers, and colouring
matters, such as burnt sugar, &c.
COD-LIVER OIL, other oils mixed with it.
COLOCYNTH (COMPOUND EXTRACT OF), the extract is not unfrequently
made with the pulp and seeds.
CONFECTIONERY, injurious colouring matters, such as arsenite of
copper, chromate of lead, &c.
CONFECTION, AROMATIC (AROMATIC CHALK POWDER), expensive
ingredients omitted, turmeric substituted for saffron, &c.,
&c.
COPAL, gum dammar, resin, &c.
CURRY-POWDER, red lead, ground rice, salt.
CUSPARIA BARK, the bark of _Strychnos Nux Vomica_ is said to have
been substituted.
CUSTARD AND EGG POWDER, turmeric, chrome yellow, and different
flours.
ELATERIUM, starch, flour, chalk, &c.
EPSOM SALTS, chloride magnesium, chalk, &c.
ETHER, alcohol.
FLOUR, other and inferior flours, as the flour from rice, bean,
Indian corn, potato, &c., sulphate of lime, alum.
GELATINE, salt and sugar.
GIN, water, sugar, capsicum, flavouring matters of different
kinds, turpentine, alum, tartar.
GINGER, turmeric, and husks of mustard, flour from wheat, sago,
&c.
GUAIACUM RESIN, other resins.
HONEY, flour, cane sugar, &c.
HOPS, _Cocculus indicus_, grains of paradise, &c., &c.
IODIDE OF POTASSIUM, water, carbonate of potash, chlorides of soda
and potash, iodate of potash, iodine, &c.
IODINE, water, plumbago, charcoal, black oxide of manganese, &c.
IPECAQUANHA, other roots, extraneous woody fibre; when in powder,
chalk, flour, &c., have been added.
ISINGLASS, gelatine.
JALAP, raspings of guaiacum, false jalap root, &c.
LARD, carbonate of soda, salt, potato, flour, and lime.
LEMON JUICE, a mixture of sugar and water, acidulated with
sulphuric acid, has been substituted.
LIQUORICE, rice, chalk, gelatine, and different flours.
MAGNESIA, MAGNESIA SULPHATE, lime, carbonate of magnesia.
MAGNESIA, CARBONATE, lime, sulphate, &c., &c.
MARMALADE, apple, or turnip pulp.
MERCURY, lead, tin, zinc, bismuth, &c.
MERCURY GREEN IODIDE OF, red iodide of
MERCURY RED OXIDE OF, brick-dust, red lead, &c.
MERCURY AMMONIATED (WHITE PRECIPITATE), chalk, carbonate of lead,
plaster of Paris, &c., &c.
MILK, water.
MUSTARD, turmeric, wheat flour.
MYRRH, gum bdellium, and other gum resins.
OATMEAL, barley flour, rubble.
OPIUM, stones, sand, clay, vegetable extracts, sugar, treacle,
water, &c.
PAREIRA ROOT, different roots substituted.
PEPPER, linseed meal, different flours, mustard husks, &c.
PICKLES, salts of copper, acetate of copper.
PORTER AND STOUT, sugar, treacle, water and salt.
POTASH, carbonate, sulphate, and chloride of potash, lime, iron,
and alumina.
POTASH, ACETATE OF, sulphates, and chlorides of potash.
POTASH, CARBONATE OF, sulphates, and chlorides of potash.
POTASH, BICARBONATE OF, carbonate of potash.
POTASH, CITRATE OF, sulphates of potash.
POTASH, CHLORATE OF, chloride of potassium.
POTASH, TARTRATE OF, tartrate of lime.
POTASH, NITRATE OF, sulphate or chloride of potassium.
PRESERVES, salts of copper.
QUININE, sulphate of lime, chalk, magnesia, cane-sugar, sulphate
of cinchonine, &c.
RHUBARB, turmeric, and inferior varieties substituted for Turkey.
RUM, water, cayenne, burnt sugar.
SAGO, potato flour.
SAUCE, treacle, salt, cochineal, Armenian bole, and other
colouring matters.
SCAMMONY, chalk, starch, guaiacum, jalap, dextrin, &c.
SENEGA, guiseng, gillenia.
SENNA, leaves of _cynanchum argel._
SHERRY, sulphates of potash, soda, brandy, burnt sugar, &c.
SNUFF, carbonate of ammonia, glass, sand, colouring matter, &c.
SODA, BICARBONATE, carbonate and sulphate of soda.
SODA, CARBONATE, sulphate of soda.
SODA, PHOSPHATE OF, phosphate of lime.
SPICES, colouring materials, substitutions, and different flours.
SQUILLS (POWDERED), wheat flour.
SUGAR (MOIST), sand, flour, &c.
SULPHUR, sulphurous acid (as an impurity).
SULPHURIC ACID, lead, water, arsenic, hydrochloric acid, &c.
TAPIOCA, mixing inferior starches with the pure tapioca.
TEA, sand, iron filings, exhausted tea leaves, foreign leaves; and
in green teas, black lead, Prussian blue, China clay.
TOBACCO, inferior tobacco, water.
TURMERIC, yellow ochre, carbonate of soda, or potash.
UVA URSI (BEARBERRY LEAVES), leaves of red whortleberry, and
others.
VINEGAR, sulphuric acid, and metallic impurities.
WINES, water, jerupiga, bitartrate of potash, substitution of
inferior wines, brandy, spirits, and various other matters.
ZINC, OXIDE OF, chalk, carbonate of magnesia.

"The Sale of Food and Drugs Act" has now supplemented several Acts which were passed during the present century for the prevention of adulteration. An Act prohibiting the mixture of injurious ingredients with intoxicating liquors remains unrepealed, as do also one or two statutes relating to trade frauds as for example the Adulteration of Seeds Act, 1809. These latter have not been incorporated in "the Sale of Food and Drugs" Act.

=Æ= ([=e]). [L.] For words sometimes written with this initial diphthong, and not found below, look under =E=.

=ÆGI'RINON= (-j[=i]'-). [Gr.] See OINTMENT.

=ÆGYPTI'ACUM=[dagger] (-j[)i]p-t[=i]'-). [Lat.] _Syn._ UNGUEN'TUM ÆGYPTIACUM, L. Oxymel or liniment of verdigris. The name originated with Hippocrates, who is said to have learned its composition in Egypt.

=ÆOL'IPILE= (-p[)i]le). A hollow ball of metal, having a slender neck with a very small orifice, contrived to exhibit the conversion of water into steam by the action of heat, and to account for the natural production of winds. It was known to the ancients, is mentioned by Vitruvius, and was studied by Descartes and others. It has been used in _surgery_ to produce eschars, in the same cases as moxas; the effect of the steam being limited by means of a piece of perforated pasteboard. When filled with alcohol, and the jet of vapour inflamed, it is sometimes employed as a blowpipe. M. Soyer used an apparatus of this kind to supply the heat in his portable furnace. The liquid, however, which he employed was camphine.

=A'ER=, ([=a]'-[)e]r). [L. prim. Gr.] Air.

=A'ERATED= ([=a]'-[)e]r-r[=a]te-[)e]d). In _chemistry_, &c., impregnated with carbonic acid. See ALKALI, LEMONADE, WATERS, MINERAL.

=AE''RIAL= ([=a]-[=e]re'-e-[)a]l). Belonging to the air or atmosphere; produced by, consisting of, depending on, or partaking of the nature of the air.

AERIFICA'TION ([=a]-[)e]r-e-). _Syn._ AËRIFICA'TIO, L.; AÉRIFICATION, GAZÉIFICATION, Fr. In _chemistry_, the conversion of a body into gas.

=A'ERIFORM= ([=a]'-[)e]r-). _Syn._ AËRIFORM'IS, L.; AÉRIFORME, GAZÉIFORME, Fr. LUFTFORMIG, &c., Ger. In _chemistry_, air-like, gaseous.

=AEROL'OGY.= _Syn._ AËROLO'GIA, L.; AÉROLOGIE, Fr., Ger. In _physics_, a discourse or treatise of the air. In _physiology_ and _hygiène_, the doctrine of the air, more especially with regard to its salubrity and action on organised beings.

=AEROM'ETER.= _Syn._ AËROME'TRUM, L.; AÉROMÈTRE, Fr. An instrument used in aërometry.

=AEROM'ETRY=. _Syn._ AËROME'TRIA, L.; AÉROMÉTRIE, Fr.; LUFTMESSKUNST, &c., Ger. In _chemistry_ and _physics_, the art of measuring gases, and of determining their densities.

=AERONAUT'ICS.= _Syn._ AÉRONAUTIQUE, Fr. The art of sailing in, or of navigating the air. See BALLOONS.

=AEROPHO'BIA.= [L.] _Syn._ AÉROPHOBIE, Fr. In _pathology_, a dread of air (wind); a common symptom in hydrophobia, and occasionally present in hysteria and phrenitis.

=AEROSTAT'ICS.= _Syn._ AÉROSTAT'ICA, L.; AÉROSTATIQUE, Fr. That branch of pneumatics which treats of air, and other elastic fluids, in a state of rest.

=AEROSTA'TION.= [Eng., Fr.] _Syn._ AËROSTA'TIO, L. The art of weighing the air; aërial suspension and navigation. See BALLOONS.

=ÆRU'GO= ([=e]-). [L.] The rust of brass, bronze, or copper; verdigris.

=ÆSCULIN.= C_{21}H_{24}O_{13}. A crystalline fluorescent substance existing in the bark of the horse-chestnut (_æsculus hippocastanum_) and of other trees of the genera _Æsculus_ and _Paria_. In the above-named sources Æsculin is associated with another fluorescent body called Pariin.

=Æ''THER.= See ETHER.

=ÆITHE''REA= (-th[=e]ré-). [L. pl.] Ethers.

=ÆSTHET'ICS= ([=e]z-). _Syn._ ÆSTHET'ICA, L. Medicines or agents which affect sensation. See ANÆSTHETICS and HYPERÆSTHETICS.

=ÆTHIOPS.= See ETHIOPS.

=AFFEC'TION.= [Eng., Fr.] _Syn._ AFFEC'TIO, L. In _pathology_, a term nearly synonymous with disease.

=AFFINITY.= _Syn._ CHEMICAL AFFINITY; AFFINITAS, L.; AFFINITÉ, Fr.; VERWANDTSCHAFT, Ger. If oil and water be shaken together they produce no change upon one another, as is proved by their separating into two layers with their properties unaltered, when the mixture is allowed to remain at rest for a short time. Such bodies are said, in chemical language, to have no affinity for one another. If iodine and metallic mercury be rubbed together in a mortar they will unite in definite proportions by weight, and form a combination possessing properties totally distinct from those of its constituents. Thus, iodine is a greyish, metallic-looking solid, convertible into a violet vapour by heat, perceptibly soluble in water, and capable of producing a blue compound with starch. Mercury is a metallic, silvery-looking liquid. The product of their union (biniodide of mercury) is a scarlet powder, destitute of metallic lustre, convertible into vapour by heat, without the production of violet fumes, insoluble in water, and incapable of developing a blue colour with starch. Again, the greenish-yellow and intensely poisonous gas, chlorine, unites in definite proportions by weight with the soft, wax-like, and highly poisonous metal sodium to produce the white crystalline solid chloride of sodium (common salt), a compound which, except in very large quantities, is not only not poisonous, but actually beneficial to health.

Such combinations are called chemical compounds, and the force which binds their constituents together is distinguished from all other attractive forces by the term affinity or chemical affinity. Bodies united by affinity are also said to have united chemically.

Affinity is in most cases exerted between different substances, in which respect it resembles adhesion; but bodies united by adhesion, _e.g._ ink to paper, paint to wood, &c., unlike those united by affinity, suffer no change of properties.

Affinity is exerted at immeasurable distances, therefore substances to be submitted to its influence must be brought into (apparently) actual contact. This condition is frequently fulfilled by the vaporisation, fusion, or solution of one or more of the bodies to be submitted to its action.

In many instances substances which have no affinity for one another at ordinary temperatures manifest this power when heated.

Whenever chemical union takes place, heat is invariably evolved; conversely, the decomposition of a chemical compound is always accompanied by an apparent loss of heat or reduction of temperature.

Finally, the most striking phenomena characteristic of, and accompanying, chemical affinity are, development of heat, change of properties, and union in definite or constant proportions by weight.

=AFFUSION.= In _chemistry_, the washing of a precipitate, &c., for the purpose of removing soluble matters. In _medicine_, affusion is of three kinds:--

1. _Lotions_, which consist in washing a part of the body with a sponge or rag soaked in a liquid.

2. _Aspersions_, which consist in throwing a liquid drop by drop, like rain, upon the body.

3. _Shower baths_, which consist in allowing a number of small streams of water to fall from a height upon the surface of the body. If the water fall from a considerable height, affusion is then termed _douche_ by the French.

=AFT'ER-DAMP.= _Syn._ CHOKE-DAMP. Carbonic acid gas resulting from explosion of air and fire-damp (light carbonetted hydrogen) in coal mines.

=AFT'ER-PAINS.= Those following childbirth. The only remedy is patience; they may, however, be frequently alleviated by small doses of morphia or liquor opii sedativus. Heated cloths and warm fomentations are sometimes useful, particularly if assisted by moderate but sufficient pressure on the abdomen, by means of a broad bandage. They seldom follow with severity the first birth.

_Treatment for Animals._ Remove clots from parts, raise the hind-quarters. Give clysters of linseed tea, lukewarm, and laudanum or belladonna extract. Syringe out parts with Condy's fluid considerably diluted. Give internally belladonna, opium, or chloroform. Draw away milk.

=AFT'ER-WASH= (w[)o]sh). In the art of the distiller, the liquor in the still after the spirit has been drawn over.

=AG'ARIC.= [Eng., Fr.] _Syn._ AGAR'ICUM, AGAR'ICUS, L.; BLÄTTERSCHWAMM, PILZ, SCHWAMM, Ger. In _botany_, a genus of fungi, of numerous species, embracing the mushrooms and champignons. Of these plants, some are edible; others poisonous. The term is also commonly applied to the boletus found on oaks (TOUCHWOOD), and on larches (MALE AGARIC). See MUSHROOMS.

=Fly-agaric.= _Syn._ FLY MUSH'ROOM; AGAR'ICUS MUSCA''RIA, Linn.; AMANI'TA M. One of the most narcotic and poisonous of our fungi, producing, in small doses, intoxication and a pleasing species of delirium; for which purpose it is commonly employed in Kamschatka. (Hooker.) It possesses the singular property of imparting an intoxicating quality to the urine, which continues for a long time after taking it. This secretion is, therefore, commonly saved by the natives during a scarcity of the fungus. "Thus, with a few amanitæ, a party of drunkards may keep up their debauch for a week;" and the intoxication so produced is capable of "being propagated through five or six individuals." (Langsdorff.) Water in which it has been boiled is poisonous; but the boiled fungus itself is inert. The liquid from it is used as a fly-poison; whence the name mushroom is derived. It may be known by its rich orange-red colour in autumn.

=AG'ATE= (-[=a]te, -[)e]t[double-dagger]). [Eng., Fr.] _Syn._ ACHA'TES (-k[=a]'-t[=e]z), L. A semi-pellucid uncrystallised species of quartz, remarkable for its hardness, variety of colour, and susceptibility of receiving a high polish. It is an aggregate of various siliceous minerals, of which chalcedony appears generally to be the base. Carnelian, jasper, amethyst, and other similar minerals, often enter into its composition. The colours are often delicately arranged in stripes, bands, or clouds. Those which take an angular form, as the Scotch pebble, are called FORTIFICATION AGATES. It is the least valuable of the precious stones, and is chiefly made into rings, seals, beads, burnishers, &c., on account of its hardness. Its powder is used for cleansing and polishing iron, brass, &c., and to sharpen edge-tools.

=AGEING LIQUOR.= Dissolve 3 lbs. of chlorate of potash in 4 galls. of boiling water. Add 20 lbs. of powdered white arsenic to 20 lbs. of solution of caustic soda at 60° Tw., and boil until the arsenic is completely dissolved. Add the latter solution to the former, with stirring, until the mixture stands at 28° Tw.

=AG'NAIL.= See WHITLOW.

=AGRYPNOT'ICS= (-gr[)i]p-). _Syn._ ANTHYPNOT'ICS (-h[)i]p-); AGRYPNOT'ICA, ANTHYPNOT'ICA, L. In _medicine_ and _pharmacology_, agents or substances which prevent sleep; as tea, coffee, digitalis, vinegar, &c.

=A'GUE= (-g[)u]). Ague may be defined as febrile phenomena occurring in paroxysms, and observing a certain regular succession, characterised by chill, abnormal heat, and unnatural cutaneous discharge, which prove to be a temporary crisis and usher in a remission. These phenomena are developed in an uninterrupted series or succession more or less regular, which pass into each other by insensible stages. Ague is paludal fever, and has always been observed to prevail in marshy moist districts, and in low, swampy humid countries, in which seasons of considerable heat occur.

The neighbourhood of marshes, or of a district which has been at some recent time under water; the banks of extensive lakes, and the shores of rivers and seas where the water flows sluggishly, and in some places stagnates; shallow rivers; extensive level tracts of forest land, where moisture is always present; and the surface of the land constantly covered with excavation from the ground,--these are the terrestrial physical conditions, in which marsh and littoral fevers are almost universally to be found, although it must be admitted that there are some marshy districts in which the disease does not show itself.

In these latter localities the effects of the miasmatic poison, show themselves in cholera or typhus. No precise knowledge of the nature and source of this subtle poison which, in default of a better name we call _malaria_, has yet been acquired; indeed it has yet to be proved that _malaria_ has a distinct existence. Science has as yet been unable to discover the presence of any poisonous principle in the air of ague on other regions.

Ague may exist without any alteration of structure being set up; but in the milder forms of this fever a greater number of organs and tissues are morbidly altered than perhaps in any other form of disease. The parts so affected are the liver, spleen, lungs, heart, brain, and the serous and mucous membranes of the body generally. Within certain limits, the specific action of the malarial poison may be said to be in the inverse ratio of the intensity of the fever which attends its action. The affections of the liver and spleen also vary greatly according to the locality in which the patient is attacked; for instance, whilst in some parts of India the spleen is the organ principally involved, in other districts of the same continent it is the liver. In England, under proper medical treatment, the patient usually recovers without any manifest derangement either of structure or impairment of function of any organ or tissue. The liver may, however, become affected if the patient suffering from the disease has been neglected for any length of time.

Notwithstanding the opinions of Finke and Professor Colin, there appears to be considerable ground for the supposition that ague may be caused by drinking marsh and surface water. In an interesting paper on the 'Indian Annals' for 1856, Mr Bettington, of the Madras Civil Service, says:--"It is notorious that the water produces fever and affections of the spleen." In confirmation of this assertion, he brings forward what seems to be some remarkably strong evidence. He cites cases of villages placed under the same conditions as to marsh-air in some of which fevers were prevalent, whilst in others they were absent; and he found on inquiry that whilst the latter villages were supplied with pure water, the inhabitants of the former had to drink marsh or mullah water, full of vegetable _débris_. In one village there were two sources of supply--a spring and a tank, the first fed by surface, and the other by marsh water. Those only who partook of the tank water were attacked by fever. Again, in Tulliwaree the fever was so universal that scarcely any inhabitant escaped it. In this village Mr Bettington caused a well to be dug, and the result was that the fever disappeared. Similar cases have occurred in this country. Twenty years ago Mr Blower, of Bedford, directed the attention of medical men to a case that occurred in a village, in which ague had nearly disappeared when a well was dug; and to another instance which occurred in the village of Houghton. In this parish almost the only family which escaped ague was that of a farmer; the members of this family partook of well water; whilst those who did not escape the disease drank ditch water.

In the 'Indian Annals' for 1867 is a paper by Dr Moore, confirming the opinion that ague may be produced by the causes already stated, and M. Commaille ('Rec. de Mêm. de Med. Mil.,' Nov., 1868) states that in Marseilles, paroxysmal fevers, formerly unknown, have made their appearance, since the water supply to that city has been drawn from the Marseilles Canal.

In his report for 1870 Dr Townsend, the Sanitary Commissioner for the central provinces of India, states that the natives of India hold an opinion that the use of river and tank water during rainy seasons (when the water always contains an increased quantity of vegetable matter) will almost always cause ague. Boudin ('Traité de Géographie et de Statistiques Médicale,' 1857, t. i, p. 142), records an extraordinary case. Eight hundred soldiers, in good health, embarked in three vessels to pass from Bona, in Algiers, to Marseilles, in the year 1834. They all arrived at Marseilles the same day. In two vessels there were 680 men, without a single sick one amongst them. In the third vessel, the Argo, there had been 120 soldiers; 13 died during the short passage, and of the 107 survivors no less than 98 were disembarked suffering from all forms of paludal fevers. We may presume that the diagnosis was correct, since Boudin himself examined the men. When the vessels started the crew of the Argo had not a single sick man aboard. The crew and soldiers of all the boats were exposed to the same atmospheric conditions. The influence of air must, therefore, be excluded. There is no mention of food, but it has never been suggested that food has ever been concerned in the production of malarious fever. It was a very different matter, however, with the water supply. In two of the vessels the water was good, whilst the Argo had been supplied with marsh water, which was offensive to the smell, as well as unpalatable. This latter was supplied to the soldiers, whilst the crew drank uncontaminated water. Amongst those who deny that marsh water is the cause of ague must be quoted Professor Colin. The professor, who is regarded as an authority on intermittent fever, in his work De l'Ingestion des Eaux Marécageuse comme cause de la Dysenterie et des Fièvres intermittentes,' instances numerous cases in Algiers and Italy in which impure marsh water gives rise to indigestion, diarrh[oe]a, and dysentery, but in no case to intermittent fever; and he states that in all his observations he has never met with an instance of ague having such an origin. Without contesting the case of the Argo, he views it with considerable suspicion, and doubts whether Boudin is correct in his details. Finke also states that, in Hungary and Holland, marsh-water is daily drank without causing any ill-effects. The inhalation of the fumes of oxide of zinc appears to produce in workers of this metal a variety of ague termed by Shackrah "brass ague," and by Dr Greenhow, "brass-founder's ague." The symptoms of the malady are tightness and oppression of the chest; with indefinite nervous sensations, followed by shivering, an indistinct hot stage, and profuse perspiration. These attacks, however, are not periodical.

It is open to doubt whether the malarious poison exists in the form of a gas, for the observations of microscopists go to show the extreme minuteness of the germs of disease, which are probably not more than 1/70000th of an inch in size, and it is regarded as probable that the real cause of ague is the entry into the circulation of some low forms of spores of fungi, or of some minute animalcules. Ague is always to be met with in places where fungi grow, and is always associated with what Pettenkofer calls "the ground air"--that is, the air contained in the interstices of the soil, no inconsiderable volume of which is drawn into every house which has a fire on the floor which rests on the earth. That animalcules (?) may exist in the blood is evidenced by the discovery of Dr Lewis, who found hair-like worms in the circulation; and whilst considering this point, we must bear in mind that the remedial agents employed to check ague, quinine, arsenic, &c., are drugs capable of destroying animal life, and it is not impossible that they may exercise a beneficial effect in destroying the spores or animalcules to which the disease may be due.

The best means to be employed to combat malarial fevers in any district are thorough and efficient drainage (and it must be remembered that drainage purifies both the ground-air and the ground water) and a supply of wholesome water free from decomposing vegetable matter.

That the adoption of the above means cannot fail to succeed is incontestably proved by the fact, that during the last 200 years, ague in England has diminished to a wonderful extent, in short, as good drainage and a pure water supply have prevailed, there has been a proportionate diminution of paludal poisoning.

During the protectorate of Cromwell great mortality prevailed in London, from the ravages of ague; at that time London was as swampy as the fens of Lincolnshire. See FEVER (Intermittent).

=Ague-cake.= The popular name of a tumour felt under the false ribs on the left side, formed by enlargement and induration of the spleen, following protracted ague; also, sometimes, of indurations of the liver following ague.

=Ague-drop.= See DROPS.

=Ague-salt= (s[)o]lt). Disulphate of quinine.

=Ague-tree.= Sassafras.

=Ague-weed.= The herb thorough-wort ('Eupato''rium perfolia'tum,' Linn.).

=AIG'REMORE= ([)e]g'r-mor). [Fr.] Pulverised charcoal in the state it is used to make gunpowder.

=AIGUILLETTE= (ATTELETTE). [Fr.] In _cookery_, a term applied to several small dishes, from the articles of which they consist being mounted on silver needles, or skewers, with ornamental handles or tops. (See _engr._) They form one of the varieties of the 'hors-d'[oe]uvres' of Soyer; and are commonly served on a napkin. The skewers should be about four inches long, and of the thickness of an ordinary packing needle. The person eating what is served on them takes the head of the skewer between the thumb and fingers of the left hand, and picks it off with his fork. Those noticed by Soyer are--

=Aiguillettes à l'Éperlan= (_smelts_);

=Aiguillettes aux Huitres= (_oysters_);

=Aiguillettes de Filets de Sole= (_soles_);

=Aiguillettes de Homard= (_lobsters_);

=Aiguillettes de Langue de B[oe]uf= (_ox-tongue_);

=Aiguillettes de Ris de Veau= (_sweetbread of veal_);

=Aiguillettes de Volaille à la Jolie Fille= (_fowl_);--

all of which are prepared in a nearly similar manner, merely varying the sauces, &c., to suit the article and palate. See ATTELETTES, HORS-D'[OE]UVRES, &c.

=AHORNZUCKER= (genuine American maple sugar). For coughs, hoarseness, and all affections of the throat and chest caused by cold. The raw maple sugar as imported. (Hager.)

=AILANTHUS.= The inner bark of the _ailanthus glandulosa_, a common tree growing in northern China, said by Dr Dudgeon to have proved very successful in dysentery.

The _ailanthus glandulosa_ is also well known throughout the United States. Professor Hétet, of Toulon, tried the effect of the powdered bark, leaves, and various preparations of the bark or drugs, with the result of their administration being attended with purgative effect--and the discharge of worms.

The powdered bark has been given in small cases of tape-worm in the human subject, with marked success. The dose of the powder found sufficient for the expulsion of the tapeworm was from seven or eight to thirty grains.

=AIL'MENT.= Pain, indisposition; disease. Its use is generally restricted to the non-acute, and milder forms of disease.

=AIR.= [Eng., Fr.] _Syn._ Aer, L. (from [Greek: aêr] Gr.); LUFT, Ger.; ATMOSPHERIC AIR; THE ATMOSPHERE. This name was formerly given to any aëriform body; thus, by the old chemists ammoniacal gas was called alkaline air; oxygen,--dephlogisticated, vital, or empyreal air; carbonic anhydride (carbonic acid), fixed air; hydrogen, inflammable air; heavy carbonetted hydrogen, olefiant gas, heavy inflammable air; nitrogen,--mephitic, phlogisticated, or nitrous air. At the present time the term air is usually restricted to the gaseous envelope surrounding the solid and liquid parts of our globe.

=Air, Atmospheric= (or simply, The Air). The air chiefly consists of a mechanical mixture of four volumes of nitrogen and one volume of oxygen, or more accurately--

By volume. By weight.
Nitrogen 79·1 76·8
Oxygen 20·9 23·2
----- -----
100 100[12]

[Footnote 12: At a meeting of the Paris Academy of Sciences, held on the 31st of December, 1877, it was announced that M. Cailletet had succeeded in liquefying atmospheric air.]

We may premise our description of the functions of the constituents of the atmosphere by the following quotation from Mr Blyth's 'Dictionary of Hygiène and Public Health':--"One of the most important properties of air is its power of penetration and its universality. Air is, indeed, present everywhere; there is scarcely a solid, however compact it may appear to be, which does not contain pores, and these pores filled with air. The soil contains no small quantity; indeed, if it were not so the numberless insects, worms, &c., which burrow in its interstices would cease to exist. The most compact mortar and walls are penetrated with it, and water of natural origin contains a large quantity of air in solution. The atmosphere is supposed to extend to a very great height, from 200 to 300 miles; it used to be considered only five (forty-five) miles high, but observations on shooting stars, &c., show that this opinion is erroneous. Owing to the force of gravity, the air is much denser near the earth, and gets more attenuated layer by layer as you ascend. If, then, the atmosphere were possessed of colour, it would be very dark just round the globe, and the tint would gradually fade into space. The air is by no means wholly gaseous; it contains, indeed, an immense amount of life, and small particles derived from the whole creation. In the air may be found animalcules, spores, seeds, pollen cells of all kind, vibriones, elements of contagion, eggs of insects, &c., and a few fungi, besides formless dust, sandy, and other particles of local origin; for example, no one can ride in a railway carriage without being accompanied with dust, a great portion of which is attracted by a magnet, and is, indeed, minute particles of iron derived from the rails. The purest air has some dust in it. There probably never fell a beam of light from the sun since the world was made which did not show, were there eyes to see it, myriads of motes; these, however, generally speaking, are quite innocuous to man--some, indeed, may possibly be beneficial. Another most important property of air is its mobility; on the calmest day and in the quietest room there are constant currents of air which rapidly dilute any noxious odours of gases."

The chief functions of the oxygen are to maintain respiration and support combustion, while the office of the nitrogen is to dilute the oxygen and control its energy.

Besides nitrogen and oxygen, aqueous vapour, carbonic anhydride, ammonia, and nitric acid are met with in the atmosphere, the last especially during and shortly after thunder storms.

Although, doubtless owing to local conditions, trifling variations may occur in the proportion of oxygen present in the atmosphere, this variation is so trifling that the difference of the amount in air from places separated by very long distances will be found in the second decimal place only; thus, whilst a portion of air taken during a balloon ascent by Mr Green gave on analysis 20·88 per cent. by vol., Dr Frankland found in air collected by himself on the summit of Mont Blanc 20·96 per cent. by vol. A still nearer approximation in uniformity in the amount of oxygen present in atmospheric air is exhibited in the following table, which gives the results of 95 analyses by Regnault on air obtained from nine different localities:--

100 from Paris gave in 100
parts, by vol. of oxygen 20·913 to 20·999
9 from Lyons and around
gave in 100 parts, by vol.
of oxygen 20·918 to 20·966
30 from Berlin gave in 100
parts, by vol. of oxygen 20·908 to 20·998
10 from Madrid gave in 100
parts, by vol. of oxygen 20·916 to 20·982
23 from Geneva and Switzerland
gave in 100 parts,
by vol. of oxygen 20·909 to 20·993
15 from Toulon and Mediterranean
gave in 100
parts, by vol. of oxygen 20·912 to 20·982
5 from Atlantic Ocean gave
in 100 parts, by vol. of
oxygen 20·918 to 20·965
1 from Ecuador gave in 100
parts, by vol. of oxygen 20·960
2 from Pichincha gave in
100 parts, by vol. of
oxygen 20·949 to 20·981
------ ------
Mean of all foregoing 20·949 20·988
" of the Paris specimens 20·96

Vapour of water is essential to the respiration of animals and plants, in order that the organs concerned in this operation may be kept in a soft and moist condition.

Carbonic anhydride is evolved during combustion, putrefaction, and fermentation; it is also a product of the respiration of animals, and highly poisonous to them, even when diluted with large proportions of air. This gas is, however, greedily absorbed by plants, which decompose it; they assimilate the carbon and return the oxygen to the atmosphere, ready to be again consumed in supporting the life of the animal world.

Dr Angus Smith has defined a very pure air to be one that contains with 20·99 per cent. of oxygen 0·30 of carbonic acid (anhydride).

This latter varies in amount in the atmosphere of cities, as will be seen upon inspection of the subjoined table, extracted from Dr Smith's work 'Air and Rain':--

Per cent.
Air of Madrid, outside the walls, mean of 12 analyses, by Luna ·045
Mean of 12 analyses, within the walls of Madrid, by Luna ·051
Mean of 14 analyses, by Angus Smith, in Manchester suburbs ·369
In Manchester streets ·403
Usual weather ·0403
During fogs ·0679

De Saussure's analyses show that there is more carbonic acid on the mountains than in the plains, as might be inferred from the comparative absence of vegetation in elevated positions. Dr Pietra Santa states that the air of hills or mountains, at the height of 2300 feet, is lighter than common air, contains a smaller proportion of oxygen, and is impregnated with a largely increased amount of aqueous vapour. It also contains a large quantity of ozone. He considers such a climate peculiarly soothing to persons suffering from chest diseases.

Dr Angus Smith's analysis of the air from the mountainous districts of Scotland confirms the above statement of Dr Pietra Santa's. The heaths and mountains of that country are remarkably healthy localities, and the air from them gave on analysis 20·94 per cent. by vol. of oxygen, and only ·033 of carbonic acid.

Ammonia is derived from the putrefaction of animal and vegetable substances. It is from atmospheric ammoniacal compounds that plants obtain much of the nitrogen which is essential to the formation of many parts of their structure.

Nitric acid, like ammonia, is absorbed, and its nitrogen assimilated, by plants.