Cooley's Cyclopaedia of Practical Receipts Volume Ii Part 288

=VENTILA'TION.= The proper ventilation of our habitations, as well as of other buildings in which we pa.s.s any considerable portion of our time, is quite as necessary to health as food and clothing. Lavoisier, writing in the middle of the last century, remarks--"It is certain that mankind degenerate when employed in sedentary manufactures, or living in crowded houses, or in the narrow lanes of large cities; whereas they improve in their nature and const.i.tution in most of the country labours which are carried on in the open air." Yet many persons, by the care which they take to shut out fresh air, and to prevent the escape of that which their own bodies, by pulmonary and surfacial respiration, have contaminated, would seem to hug to themselves the discomfort of breathing over and over again an impure and unrefreshing atmosphere, and to be anxious to finish their career by lingering suicide. The almost universal indifference to the subject, considering its importance, is unaccountable.

The first step towards effecting and maintaining a liberal supply of fresh air is either by means of ventilators or by regularly opening the windows for stated periods daily. During the colder portions of the year, when fires are kept burning, and there is an up-current in the chimney, nothing is so simple and effective as the well-known chimney-valve of Dr Arnott; and, indeed, without this, open fires are powerful instruments of ventilation. In cold weather, where expense is not an object, the apartments may be supplied with air that has been previously warmed by pa.s.sing through a heated chamber, on the principle recommended by Dr Reid; but care must be taken that, in warming the air, we do not overheat it, nor contaminate it.

A sufficient supply of light, another powerful sanitary agent, is now regarded as nearly as essential as thorough ventilation, and the two are commonly treated of together. According to Palladio, the opening of windows should not exceed a fourth, nor be less than a fifth, of the length of the side of a room, and should be in height two and one sixth times the width. Mr Gwilt, another high authority on this subject, has given as a definite rule, that we should allow 1 square foot of gla.s.s to every 100 cubic feet of s.p.a.ce in any apartment or inclosure. A great deal must, however, depend on the shape of the apartment; but, in all cases, care should be taken that the windows are placed at the longest side of the room, and not at the narrowest, or the end of it. A southern aspect affords the most light and heat; a northern one the most diffused and least variable light, and is hence usually chosen by artists for their studios.

=VERA'TRINE.= C_{32}H_{52}N_{2}O_{8} _Syn._ VERATRIA, VERATRINA, SABADILLINE; VERATRIA (B. P., Ph. L., & E.), L. An alkaloid discovered by Pelletier and Caventou, in the seeds of _Asagreae officinalis_ (sabadilla), and in the rhizomes of _Veratrum alb.u.m_ (white h.e.l.lebore).

_Prep._ 1. (Ph. E.) Digest sabadilla seeds in boiling water for 24 hours, then squeeze them, dry them thoroughly by a gentle heat, beat them in a mortar, and separate the seeds from the capsules by agitation in a deep and narrow vessel; next grind the seeds in a coffee-mill, and exhaust them by percolation with rectified spirit; concentrate the resulting tincture by distillation, so long as no deposit forms, and pour the residuum, whilst still hot, into 12 times its volume of cold water; then filter through calico, and wash the residuum on the filter as long as the washings yield a precipitate with ammonia; unite the filtered liquid with the washings, add ammonia in excess, collect the precipitate on a filter, wash it slightly with cold water, and dry it first by imbibition with filtering paper, and then in the vapour bath. "The product is not pure, but sufficiently so for medical use. From this coloured substance it may be obtained white, but at considerable loss, by solution in very weak hydrochloric acid, decolorisation with animal charcoal, and reprecipitation with ammonia."

2. (Ph. L. 1836.) This is the same in principle as the last; a tincture is formed by boiling the seeds in rectified spirit, which is then evaporated to a syrup, dissolved in very dilute sulphuric acid, the veratrine precipitated with, magnesia, redissolved in very dilute acid, treated with animal charcoal, the filtrate again evaporated to a syrup, and precipitated with ammonia; it is, lastly, washed and dried.

3. By means of ether, as noticed under ALKALOID and ACONITINE. This is by far the best method.

4. (B. P.) Cevadilla, 2 lbs.; distilled water, q. s.; rectified spirit, q. s.; solution of ammonia, q. s.; hydrochloric acid, q. s.; purified animal charcoal, 60 gr. Macerate the cevadilla with half its weight of boiling distilled water in a covered vessel for 24 hours. Remove the cevadilla, squeeze it, and dry it thoroughly with a gentle heat. Beat it now in a mortar and separate the seeds from the capsules by brisk agitation in a deep narrow vessel, or by winnowing it gently on a table with a sheet of paper.

Grind the seeds in a coffee mill, and form them into a thick paste with rectified spirit.

Pack this firmly in a percolator, and pa.s.s rectified spirit through it till the spirit ceases to be coloured. Concentrate the spirituous solution by distillation, so long as no deposit forms, and pour the residue, while hot, into 12 times its volume of cold distilled water. Filter through calico, and wash the residue on the filter with distilled water, till the fluid ceases to precipitate with ammonia. To the united filtered liquid add the ammonia in slight excess, let the precipitate completely subside, pour off the supernatant fluid, collect the precipitate on a filter, and wash it with distilled water till the fluid pa.s.ses colourless. Diffuse the moist precipitate through 12 oz. of distilled water, and add gradually, with diligent stirring, sufficient hydrochloric acid to make the fluid feebly but persistently acid.

Then add the animal charcoal, digest at a gentle heat for 20 minutes, filter, and allow the liquid to cool. Add ammonia in slight, excess, and when the precipitate has completely subsided, pour off the supernatant liquid, collect the precipitate on a filter, and wash it with cold distilled water till the washings cease to be affected by nitrate of silver accidental with nitric acid. Lastly, dry the precipitate, first by imbibition, with filtering paper, and then by the application of a gentle heat.

_Prop._ Pure veratrine is perfectly white; but as usually met with, it is a yellowish or greenish-white powder; it is highly acrid; uncrystallisable; scarcely soluble in water, soluble in ether, and freely soluble in hot alcohol; heated to about 125 Fahr., it fuses like wax, and solidifies, upon cooling, to a transparent yellow ma.s.s. With the dilute acid it forms salts, which are either amorphous or difficulty crystallisable. The smallest possible portion of its powder causes violent sneezing.

_Tests._ 1. Pota.s.sa, ammonia, and their carbonates, give flocculent white precipitates which at first are not crystalline under the microscope, but which, after some minutes, a.s.sume the appearance of small scattered cl.u.s.ters of short prismatic crystals; they are insoluble in excess of pota.s.sa and its carbonate, and only very slightly so in excess of ammonia.--2. With sulphuric acid it strikes an intense red colour, changing afterwards to crimson, and finally to violet.--3. A dilute acetic solution of veratrine is turned to a superb red by strong sulphuric acid.

Veratrine is distinguished from brucine and the other alkaloids by its fusibility--by the crystalline form of its precipitate with pota.s.sa, and--by its reaction with oil of vitriol.

_Uses, &c._ "As an external application, it has been efficaciously employed by Magendie in France, and by Dr Turnbull in this country; but the extravagant eulogies of the latter have not tended to confirm the reputation of this remedy." (Dr A. T. Thomson.) From 6 to 12 gr., dissolved in 1 fl. oz. of rectified spirit, as a liniment; or 30 gr., mixed with 1 dr. of olive oil, and 1 oz. of lard, as an ointment, have been occasionally found very serviceable in neuralgia, and other like painful affections, and in gouty and rheumatic paralysis. As an internal remedy it possesses no advantage, as it merely acts as a violent and depressing cathartic.--_Dose_, 1/24 to 1/16 gr. In larger doses it acts as a powerful irritant poison. For antidotes, &c., see ALKALOID.

=VERA'TRUM.= See WHITE h.e.l.lEBORE.

=VER'DIGRIS.= _Syn._ aeRUGO, L.; VERT-DE-GRIS, Fr. This is a mixture of several basic acetates of copper which have a green or blue colour. It is obtained in the wine districts of the south of Europe, by the action of refuse grapes, from which the juice has been expressed, on thin sheets of copper. When pure it should dissolve, almost entirely, and without effervescence, in dilute sulphuric acid. It is very poisonous; for antidotes, see COPPER.

An inferior quality of verdigris is now prepared from pommage, or apple marc, in the cider districts of England.

=Verdigris, Distilled.= _Syn._ CRYSTALLISED VERDIGRIS. This name is applied to the normal acetate of copper, which is prepared in the wine districts by dissolving ordinary verdigris, 1 part, in good distilled vinegar, 2 parts; the operation being performed in a copper vessel by the aid of a gentle heat and agitation; the solution is afterwards slowly evaporated until a pedicle begins to form on the surface, when it is transferred into glazed earthen pans ('oulas'), in each of which are placed 2 or 3 cleft sticks, and it is then left in a warm apartment for 14 or 15 days to crystallise.

A spurious article is often prepared by adding a solution of sulphate of copper, 12-1/2 lbs. to a solution of sugar of lead, 19 lbs., or q. s., and filtering, evaporating, and crystallising the mixture.

There is an acetate of copper and lime which resembles distilled verdigris in colour. It was manufactured pretty extensively in Scotland some years ago, and fetched a high price, till Dr Ure published an a.n.a.lysis of it in the 'Edin. Phil. Trans.' It is much inferior for all uses in the arts.

Pure distilled verdigris is entirely soluble in water, and is not precipitated on the addition of sulphuric acid or of ammonia in excess.

=Verdigris, English.= _Prep._ Blue vitriol, 24 lbs.; white vitriol, 16 lbs.; sugar of lead, 12 lbs.; alum, 2 lbs. (all coa.r.s.ely powdered); mix, and heat them in a pot over the fire until they unite into a ma.s.s. Sold by fraudulent dealers for foreign verdigris.

=VER'DITER.= _Syn._ BLUE VERDITER, REFINER'S VERDITER; CENDRES BLEUES, Fr.

A blue pigment, obtained by adding chalk, whiting, or milk of lime, to a solution of copper in nitric acid; or, by triturating recently precipitated and still moist carbonate of oxide of copper with hydrate of lime.

_Prep._ A quant.i.ty of whiting or milk of lime is put into a tub, and upon this the solution of copper is poured; the mixture is stirred every day for some hours together, until the liquor loses its colour; it is then poured off, and more solution of copper added; this is repeated until the whiting or lime has acquired the proper colour; the whole is then washed with water, drained, spread on chalk stones, and dried in the sun.

_Obs._ The cupreous solution employed in the above process is made by neutralising the nitric solution obtained from the refiners of gold and silver, by heating it along with metallic copper. For the finer qualities of verditer the lime should be of the purest kind, and the cupreous precipitate should be carefully triturated with it, after it is nearly dry, by which a fine velvety appearance is produced. The 'cendres bleues en pates' of the French differ from the above mainly in a solution of chloride of copper being employed, and in the resulting green precipitate being turned blue by the action of carbonate of pota.s.sa. Verditer is made into crayons whilst moist, or dried into a powder, or it is used as a water colour in the moist state.

=Verditer, Green.= _Syn._ BREMEN GREEN. The process for refiner's verditer frequently miscarries, and a green colour is produced instead of a blue one. It may also be obtained directly by omitting the 'blueing up' with carbonate of pota.s.sa, mentioned above.

=VER'JUICE.= _Syn._ AGRESTA, OMPHACIUM, L. The expressed juice of unripe grapes. The term is also often extended to the expressed juice of the wild or crab apple. It was formerly used as an astringent and refrigerant in medicine; but it is now princ.i.p.ally employed as an ingredient in sauces, ragots, &c.

=VERMICEL'LI.= This, like macaroni, is prepared from a stiff paste made of a peculiar fine kind of granular wheat flour, called semoule, which is mixed up with hot water, and, after being well kneaded, is formed into small ribands, cylinders, or tubes, by being placed in a vertical cylinder press, the bottom of which is filled with proper-shaped holes, through which it is driven by an iron plate or 'follower' being forced down by a powerful screw. The pieces that protrude are broken off, twisted into any desired shape upon paper, and dried. Those in the form of fillets or ribands are called 'lazagnes.' Vermicelli contains a large amount of gluten, and is extremely nutritious, although slightly less digestible than the ordinary wheaten foods. See MACARONI.

=VER'MIFUGES.= _Syn._ ANTHELMINTICS; ANTHELMINTICA, HELMINTHAGOGA, VERMIFUGA, L. Medicines employed to destroy or expel intestinal worms.

Some of these, as coa.r.s.ely powdered tin and iron filings and cowhage, act as mechanical agents, by irritating the worms; others have a specific action upon worms, as male fern, kousso, santonin, &c.; others, again, owe their power to their action as purgatives, as calomel, gamboge, jalap, &c.

See WORMS.

=VERMIL'ION.= _Syn._ FACt.i.tIOUS CINNABAR, RED SULPHIDE OF MERCURY, RED SULPHURET OF MERCURY. This article may be prepared both in the moist and dry way; that of commerce is almost entirely obtained by the latter.

_Prep._ 1. By sublimation. Take of pure mercury, 202 parts; pure sulphur, 33 parts; fuse them together by a gentle heat, observing not to allow the ma.s.s to take fire; when fused, cover over the vessel, and, when the whole has become cold, powder the ma.s.s, and sublime it in a closed vessel, so placed in a furnace that the flame may freely circulate and play upon it to about half its height, the heat being at first gradually applied, and afterwards augmented until the lower part of the subliming vessel becomes red hot; the cold sublimate is broken into pieces, ground along with water to a fine powder, elutriated, pa.s.sed through a sieve, and dried. _Prod._ Fully 112% of the weight of the mercury employed.

2. In the humid way. (Brunner.) Take of pure quicksilver, 300 parts; pure sublimed sulphur, 114 parts; triturate them together for several hours, until a perfect 'ethiops' is formed, add gradually of caustic pota.s.sa, 75 parts, (dissolved in) water, 450 parts; continue the trituration for some time longer, then gently heat the mixture in an iron vessel, at first constantly stirring, but afterwards only from time to time, observing to keep the beat at about 113, or, at all events, under 122 Fahr., and to add fresh water, to compensate for the portion evaporated. When the colour begins to redden, great caution is requisite to preserve the mixture at the lower temperature, and to keep the sulphuret of mercury perfectly pulverulent; as soon as the colour becomes nearly 'fine,' the process must be conducted with increased caution, and at a lower heat for some hours, or until a rich colour is produced, when the newly-formed vermilion must be elutriated with water, to separate any particles of metallic mercury, and carefully dried. _Prod._ 332 parts of vermilion, equal in brilliancy to the finest Chinese.

_Obs._ It has been said that the rich tone of Chinese vermilion may be imitated by adding to the materials 1% of sulphuret of antimony, and by digesting the ground sublimate, first in a solution or sulphuret of pota.s.sium, and next in diluted hydrochloric acid, after which it must be well edulcorated with water, and dried. Our own belief is, that the finer qualities of vermilion owe their superiority of shade more to the care bestowed on their sublimation, and the extent to which their division is carried, than to anything else.

Vermilion is a beautiful and permanent red pigment, and works and covers well both in oil and water.

=VERMIN.= This term has rather a large application, since, although it is generally understood to be applied to rats, mice, and certain parasitic insects infesting the dwellings and sometimes the bodies of men, it is extended by the farmer, the gardener, and the breeder of game, to those creatures from the depredations of which these three cla.s.ses suffer pecuniary loss. Hence it embraces not only foxes and polecats, but weasels, stoats, hedgehogs, owls, hawks, kites, carrion crows, magpies, wood-pigeons, hares, rabbits, rooks, moles, and small birds.

Whilst the attempted partial destruction of any of the cla.s.ses of animals or birds above specified may be regarded as of doubtful value, there can be no question about the practice when it is carried to the verge of extermination.

In this latter case the balance of nature is interfered with, and the system of checks which she has established for the prevention of the undue preponderance of one tribe of the animal kingdom over the other being interfered with, the result will be the undue propagation of particular species inimical to the operations of the husbandman, &c.

As ill.u.s.trating this, we may mention the destruction to various crops in France caused some years ago by the ravages of certain grubs and insects, the unusual increase in the numbers of which was clearly traced to the foolish practice, amongst French farmers, of shooting all the small birds.

See BUG, LOUSE, RATS.

=VERT'IGO.= Dizziness and swimming of the head. In its more serious forms there is more or less mental confusion, the objects around the patient appear in motion, the ears are oppressed with strange sounds, and visible illusions are experienced, whether the eyes be closed or open, and in darkness as well as in the light. The causes are fulness of the vessels of the head, nervous derangement, general debility, haemorrhage, the use of narcotics, an overloaded stomach, and, in some cases, an empty one. It is also frequently symptomatic of fevers and inflammations, and of a condition threatening apoplexy. The treatment must be varied, according to the cause and the peculiar habit or condition of the patient.

=VES'ICANTS.= _Syn._ EPISPASTICS; EPISPASTICA, VESICANTIA, L. Substances which vesicate or raise blisters. Among these are the cantharis or blistering fly, mezereon, croton oil, boiling water, &c.; the first only of which is now in common use in England.

"It is a principle sufficiently established with regard to the living system, that, where a morbid action exists, it may often be removed by inducing an action of a different kind, in the same or a neighbouring part. On this principle is explained the utility of blisters in local inflammation and spasmodic action, and it regulates their application in pneumonia, gastritis, hepat.i.tis, phrenitis, angina, rheumatism, colic, and spasmodic affections of the stomach--diseases in which they are employed with the most marked advantage. A similar principle exists with respect to pain; exciting one pain often relieves another. Hence blisters often give relief in toothache, and some other painful affections. Lastly, blisters, by their operation, communicate a stimulus to the whole system, and raise the vigour of the circulation. Hence, in part, their utility in fevers of the typhoid kind, though in such cases they are used with still more advantage to obviate or remove local inflammation." ('Med. Lex.')

Blisters are commonly prepared with cantharides plaster, or with some other preparation of cantharides; and, in the former case, are usually lightly covered with the powdered fly. In order to prevent the action of the cantharides upon the mucous membrane of the bladder, blistering plasters are often sprinkled with a little powdered camphor, or, better still, are moistened with camphorated ether, which leaves a thin layer of camphor. In all these cases the layer should not be too thick, for in that case the plaster would not take effect.

When it is not wished to maintain a discharge from the blistered part, it is sufficient to make a puncture in the vesicle, to let out the fluid; but when the case requires the blister to be 'kept open,' as it is called, the whole of the detached cuticle is carefully removed with a pair of scissors, and the part is dressed with either the ointment of cantharides or of savine, at first more or less diluted with lard, or simple ointment, with an occasional dressing of resin cerate. According to Mr Crowther, the blistered surface is best kept clean by daily fomentation with warm water.

Of late years, to obviate the unpleasant effects occasionally arising from the common blister, various compounds having cantharides for their base have been brought before the public. Of these, the vesicating collodion noticed under COLLODION is the most convenient and effective.

The following also deserve notice:--

1. Take of cantharides, in fine powder, 2 parts; spermaceti, 2 parts; olive oil, 4 parts; white wax, 8 parts; water, 10 parts; simmer, with constant agitation, for 2 hours, strain through flannel, separate the plaster from the water, gently remelt it with common turpentine, 1 part, and spread the ma.s.s whilst still fluid. This nearly resembles the form recommended by MM. Henry and Guibourt.

2. (P. Cod.) Distil off the ether from a concentrated ethereal tincture of cantharides, melt the oily residue with twice its weight of white wax, and spread the mixture on thin oiled silk, or on cloth, prepared with wax plaster.

3. (Oettinger.) Cantharidal ether (prepared from cantharides, l part; ether 2 parts), and sulphuric ether, of each 10 dr.; turpentine and black resin, of each 2-1/2 dr.; mix, dissolve, and apply it to the surface of stretched silk or taffeta which has been previously prepared with two coatings of a solution of isingla.s.s.