Chapter II: BLEACHING of =Linen=:--Linen may be bleached in a similar way to (1)

'cotton,' but the process is much more troublesome and tedious, owing to its greater affinity for the colouring matter existing in it in the raw state. Under the old system, several alternate buckings with pearlash or potash and lengthened exposure on the field, with one or two sourings, and a final scrubbing with a strong lather of soft soap, constituted the chief details of the process. In this way a high degree of whiteness, though not an absolutely pure or snow white, was ultimately produced. Grass-bleaching or crofting is still extensively used for linen; but it is more generally employed only for a limited time, and in combination with a modification of the system at present almost universally adopted for cotton goods; whilst, in some cases, crofting is omitted altogether, and the bleaching conducted wholly by the latter process. The following _Tables_ exhibit the outlines of the new system as at present practised in Ireland and Scotland:--

_a._ For plain sheetings:--

1. They are bucked for 12 or 15 hours in a lye made with about 1 _lb._ of pearlash (or soda-ash) to every 56 _lbs._ of cloth, and washed.

2. Crofted for about 2 days.

3. Bucked in milk of lime.

4. Turned, and the bucking continued, some fresh lime and water being added; and washed.

5. Soured in dilute sulphuric acid at 2° Twaddle.

6. Bucked with soda-ash for about 10 hours, and washed.

7. Crofted, as before.

8. Bucked again with soda-ash, as before.

9. Crofted for about 3 days.

10. Examined, the white ones taken out, and the others again bucked and crofted.

11. Scalded or simmered in a lye of soda-ash of about only 2-3rds the former strength, and washed.

12. Chemicked, for 2 hours, at 1/2° Twaddle, washed, and scalded.

13. Again chemicked, as before.

14. Soured for 4 hours, as in No. 5; washed, and finished.

This occupies 13 to 15 days, according to the weather.

_b._ For shirtings, &c.:--As the preceding, but with somewhat weaker solutions.

_c._ For goods to be subsequently printed:--

1. Bucked in milk of lime for 10 or 12 hours.

2. Soured in dilute hydrochloric acid of 2° Tw., for 3 to 5 hours, and washed.

3. Bucked with resinate of soda for about 12 hours.

4. Goods turned, reboiled as before, and washed.

5. Chemicked at 1/2° Tw., for 4 hours.

6. Soured at 2° Tw., for 2 hours, and washed.

7. Bucked with soda-ash for about 10 hours, and washed.

8. Chemicked as in No. 5.

9. Soured, as at No. 6, for 3 hours; washed, and dried.[222]

[Footnote 222: The strengths of the solutions, when not otherwise stated, are about the same as those given under COTTON (_antè_).]

_Obs._ The chief difficulty in bleaching linen arises from the fact that its colouring matter is insoluble in acid or alkaline solutions until it has been long acted upon by light, air, and moisture, as in the common process of grass-bleaching. Chlorine hastens the operation; but, unfortunately, it can only be employed towards the end of the process; as when earlier used, the colour of the raw cloth becomes set, and irremovable. To obviate this difficulty Mr F. M. Jennings, of Cork, has lately[223] introduced the joint use of an alkali and an alkaline hypochlorite (chloride) in the place of the ordinary chloride of lime. He prepares a bath of solution of soda at 5° Twaddle, which he raises by the addition of chloride of soda (or of potash) to 6 or 7°, and in this he steeps the cloth (after the first bucking and souring) for some hours, heat, or constant squeezing between rollers, being had recourse to, to facilitate the action. Souring and washing follow, when the goods are again put into the alkaline and chloride bath, as before; after which they are soured, and bucked again with soda. These last three operations are repeated until the cloth is almost white, when crofting for one half to one fourth the time required by the usual method renders it fit for the final bucking, and finishing. Indeed, it is said that if the process be very carefully managed it renders crofting unnecessary.

[Footnote 223: Patent dated 1859.]

Raw linen loses about 1-3rd of its weight in bleaching.

III. =Silk=:--Silk is usually bleached by first steeping it, and then boiling it in solutions of white soap in water, after which it is subjected to repeated rinsings, a little indigo-blue, or archil, being added to the last water to give it a pearly appearance. When required to be very white (as for gloves, stockings, &c.), the goods are cautiously submitted, for 2 or 3 hours, to the action of the fumes of burning sulphur, and then finished by rinsing, as before.

_Obs._ Boiling or sulphuring is not required for the white silk of China. Raw silk loses from 4 to 5 _oz._ per _lb._ by bleaching.

IV. =Wool=:--In bleaching raw wool it is first deprived of the yolk or peculiar natural varnish with which it is covered. For this purpose it is steeped and stirred for about 20 minutes in rather warm water (135°--140° Fahr.), either with or without the addition of 1-4th part of stale urine; after which it is placed in baskets to drain, and soon afterwards thoroughly rinsed in a stream of water, when it is again allowed to drain, and it is hung up to dry. The further operations depend on circumstances, wool being sometimes whitened in the fleece, or in the yarn, but still more frequently and extensively not till woven. When it is intended to send it in the first two forms white to market, it is hung up or spread out, whilst still wet, and sulphured (see _below_); after which it is either at once rinsed for some time in cold water, or is previously treated with a very weak bath of soft soap.

In the case of woollen fabrics the operations of purifying or whitening the wool, beyond the removal of the yolk, are, for the most part, mixed up with the weaving and working of it. The pieces leave the hands of the weaver of a dingy grey colour, loaded with oil, dirt, and dressing. They then pass to the fulling-mill, where they are treated with fuller's earth and soap, often preceded with ammonia or stale urine, after each of which they are well washed out or scoured with cold water, and are then ready for the dyer. When it is intended to obtain them very white, or to dye them of a very delicate shade, they are commonly sulphured; after which they are washed or milled in cold water for some hours, a little finely ground indigo being added towards the end, to increase their whiteness; an addition also made when the cloth is sufficiently white without the sulphuring process.

The usual mode of SULPHURING woollen goods is to hang them up on pegs or rails, or, in the case of fleece-wool, to spread it about, at the upper part of a close, lofty room or chamber, called a sulphur-stove. In each corner of this room is set a cast-iron pot containing sulphur, which, after the introduction of the goods, is set on fire, when the door at the lower part of the chamber is shut tight and clayed. This is commonly done over-night; and by the morning, the bleaching being finished, the goods are removed, washed, and azured.

Sulphuring, unless very skilfully managed, imparts a harsh feel to woollen goods, which is best removed by a very weak bath of soap-and-water (lukewarm); but the action of soap in part reproduces the previous yellowish-white tinge. Milling with cold, or lukewarm water, tinged with indigo, is the best substitute.

_Obs._ Raw wool loses from 35 to 45% of its weight by scouring, and 1 to 2% more in the subsequent operations of the bleacher; the loss being in direct proportion to the fineness of the staple.

[asterism]The above are the four principal applications of the art of bleaching; but, in technical language, the words bleaching, bleacher, bleachery, bleach-works, &c., when employed alone, are understood to have reference only to cotton and linen. This has arisen from the enormous extent of these manufactures, and from the process of bleaching them forming a business entirely distinct from that of weaving, dyeing, or printing them. The following, with the exception of the first, are of comparatively minor importance and interest:--

V. =Materials for Paper=:--Old rags for the manufacture of paper, and paper-pulp, are now almost universally bleached with chlorine or chloride of lime; the former being generally used in France, and the latter in England. The process usually consists in (1) boiling in an alkaline lye to remove grease and dirt, (2) washing, (3) pressing, (4) deviling or tearing up the pressed cake into fine shreds or pulp, (5) chemicking, with agitation, for about an hour, in a clear solution of chloride of lime,[224] followed by (6) washing, (7) souring with dilute hydrochloric acid at 1 or 2° Tw., or treatment with a solution of some antichlor, or both, and (8) a final washing and pressing. For the common kinds of paper, the operations included in No. 7 are omitted; but unless the whole of the lime-salt be removed from the pulp, the paper made of it is liable to turn brown and become rotten by age. In some cases rags are bleached before being divided and pulped. Cotton-waste is bleached in a similar way to rags.

[Footnote 224: The 'strength' varies with the colour and quality of the rags. From 2 to 4 _lbs._ per _cwt._ of rags is a common proportion; but for dyed and printed rags as much as 7 or even 8 _lbs._ per _cwt._ are often employed. It is better, however, to prolong the process with a weaker solution, than to hasten it by using the chloride in excess. Large rectangular cisterns of wood, or of slate, are commonly employed as the bleach-vessels. Cisterns of wood, or brick-work lined with gutta percha or with asphalto-bitumen, are employed in some paper-mills, and answer admirably.]

In France, the chlorine, in a gaseous form, is passed from the generators into the bleach-cisterns containing the pulp, which in this case must be fitted with close covers.

=VI. Printed Paper=, as Books, Engravings, Maps, &c.--These when stained or discoloured may be whitened by (1) wetting them with pure clean water, (2) plunging them into a dilute solution of chloride of lime, (3) passing them through water soured with hydrochloric acid, and then (4) through pure water until every trace of acid be removed. This process may be further improved by further dipping them into a weak solution of some antichlor, and again washing them, before finally drying them. It is only rare and valuable original works or specimens of art that are worth this treatment, which, owing to the very nature of paper, requires considerable address to manage. In many cases a sufficient degree of renovation may be effected by simply exposing the articles, previously slightly moistened, to the fumes of burning sulphur, followed by passing them through a vessel of pure water.

=VII. Straw, Straw-plait=, and articles made of them, are, on the large scale, usually bleached by (1) a hot steep or boil in a weak solution of caustic soda, or a stronger one of soda-ash, followed (2) by washing and (3) by exposure to the fumes of burning sulphur. To effect the last, the goods are suspended in a close chamber connected with a small stove, in which brimstone is kept burning. On the small scale, a large chest or box is commonly employed. A piece of brick, or an old box-iron heater, heated to dull redness, is placed at the bottom of an iron crock or earthen pan, a few fragments of roll sulphur thrown on, the lid instantly closed, and the whole left for some hours. Care should be taken to avoid inhaling the fumes, which are very deleterious as well as disagreeable and annoying. Straw goods are now also frequently bleached by the use of a weak solution of chloride of lime, or of water strongly soured with oxalic acid or even oil of vitriol, followed by very careful rinsing in clean water; but here, as in the former case, the natural varnish, dirt, grease, &c., must be first removed by alkalies or soap, to enable the chlorine or acid to act on the fibres.

=VIII. Wax.= Wax is bleached by first melting it at a low temperature in a cauldron, from whence it is allowed to run out by a pipe at the bottom into a capacious vessel filled with cold water.

This vessel is fitted with a large wooden cylinder, which turns upon its axis; and the melted wax falls upon this cylinder. The surface of the cylinder being always wet, the wax does not adhere to it, but becomes solid, assuming the form of ribbons as it does so, and in this shape becoming distributed through water in the tub. The wax is then removed and placed upon large frames stretched upon linen cloth, which are supported about 18 inches above the ground, and erected in a situation exposed to the air, dew, and sun. The several ribbons thus placed on the frame should not exceed an inch and a half, and they ought to be so moved about from time to time as that each part may be equally exposed. If the weather be favorable the wax will become white in a few days. It is again remelted, formed into ribbons, and exposed as before. These operations are continued in until the wax is completely bleached, after which it is melted and run into moulds.

_Concluding Remarks._ The theory of bleaching, notwithstanding the giant strides of chemistry during the last 20 years, remains still unsettled; and hence the processes employed are still, for the most part, empirical. It appears probable that chlorine acts by uniting with the hydrogen of the water, or of other compounds present, or probably with that of both, and that it is the oxygen thus liberated, and whilst in the nascent state, that is the true operative agent. Hence bleaching by chlorine, or by the hypochlorites, may be regarded as an oxidation of the colouring matter; but whether the chlorine or the oxygen effects this oxidation is of little practical importance--the result being the same--the destruction of the compound, and the removal of the colour that depends on its existence. It is doubtful whether the bleaching power of sulphurous acid is due to it as an oxidising or a deoxidising agent; but the last is probably the case, with a like destruction of the compound constituting the colouring matter. It may, however, be supposed that sulphurous acid acts as an oxidiser, as it appears to do when it decomposes sulphuretted hydrogen; or it may act by simply altering the compound by inserting itself, a view receiving some support from the fact that wool whitened by sulphuring may be restored to nearly its previous colour by merely treating it with soap or alkalies.

The bleaching power of light depends on its actinic or chemical rays, which, like chlorine, appear to act as an oxidising agent.

Chlorates, chromates, chromic acid, manganates, &c., have been proposed as bleaching agents for textile filaments and fabrics, but without success or practical advantage. Immersion in water more or less strongly impregnated with sulphurous acid has, however, been successfully substituted for the common sulphuring process, particularly for silk.

To avoid the injury of the goods by sparks, and by drops of water highly saturated with sulphurous acid falling from the roof, Mr Thom has invented a method of passing them rapidly through, or keeping them in constant motion in the sulphuring chamber. His apparatus is constructed on the principle of the washing-machine, the fumes of burning sulphur being used instead of water.

M. Tessie du Motay has proposed a new method for bleaching. He takes about equal parts of permanganate of soda and sulphate of magnesia, and dissolves them in lukewarm water. The tissues, previously freed from grease, are to be plunged into this bath until they are covered with a brown coating. They are then to be placed in a bath of sulphuric acid at 4 per cent., and rinsed after the brown matter is removed. They may be finally passed through sulphurous acid. Mr Ramsay's method consists in sprinkling with water equal parts of chloride of lime and sulphate of magnesia, when hydrochlorate of magnesia is formed. It may be remarked that none of the more modern methods of bleaching have been found, when reduced to practice, to be cheaper, better, or more advantageous to work than those sanctioned by long experience and use.

[Further information in connection with bleaching will be found under the heads ACTINISM, BLANCHING, CALICO-PRINTING, CHARCOAL, CHLORIDES (Bleaching), CHROMATES, CHROMIC ACID, HYPOCHLORITES, HYPOCHLOROUS ACID, LIGHT, RINSING, SPOTS and STAINS, SULPHURATION, WASHING, &c.; also under BONES, ENGRAVINGS, FAT, FEATHERS, HORN, IVORY, OIL, PAPER, PRINTED BOOKS, RAGS, SPONGE, STRAW-PLAIT, TALLOW, WAX, &c.[225]]

[Footnote 225: An accurate description of the apparatus and machinery employed in bleach-works, with numerous engravings, will be found in Ure's 'Dict. of Arts, Manuf. & Mines,' 5th ed., i, 318-351, &c.]

=Bleaching Liq'uid.= Solution of chloride of lime.

=Bleaching Pow'der.= Chloride of lime.

=Bleaching Salts.= The commercial hypochlorites.

=BLEAR'-EYE= (bl[=e]re'-[=i]). _Syn._ LIPPITU'DO, L.; CHASSIE, LIPPITUDE, Fr. An exudation of a puriform matter from the margins of the eyelids, which are red, tumid, and painful; and frequently, during the night, glued together by the discharge.

_Treatm._ Mild astringent collyria, as those of sulphate of zinc or alum (6 or 8 gr. to 1 oz. of water). An ointment formed of 1 part of the ointment of nitrate of mercury (Ph. L.), diluted with 11 parts of sweet washed lard, may be advantageously applied nightly, by means of a camel-hair pencil, the smallest quantity possible only being used. Excess in eating and drinking should be avoided, and some aperient medicine taken.

=BLEAK= (bl[=e]ke). _Syn._ BLAY[double-dagger], BLEY[double-dagger], (bl[=a]). The _cypri'nus albur'nus_ (Linn.), a small river-fish, the scales of which are used in making artificial pearls (which _see_).

=BLEB.= A vesicle or blister. In some states of general derangement of health this arises spontaneously. It should be treated in the same way as scalds.

=BLEED'ING= (bl[=e]de'-). In the sense of a flow or loss of blood, see HÆMORRHAGE; in that of bloodletting, see CUPPING, LEECHING, VENESECTION, &c.

=Bleeding Piles.= Take every morning aperient doses of milk of sulphur, then a small teaspoonful of confection of black pepper every day. Wash externally with a sponge and cold water. Apply compound gall. ointment to the piles if external.

=Bleeding from the Air Passages and Lungs.= Let the patient at once go to bed, and keep perfectly quiet, avoiding movement of any kind as much as possible. Administer dilute acids in frequently repeated doses, with five drops of tincture of digitalis. The bowels should be kept open by means of Epsom salts in infusion of roses. Give iced drinks and let solid ice be sucked. Mustard plasters may be applied to the chest. A morphia lozenge may now and then be sucked gradually away, as well as a small piece of sal prunella. The cough must be allayed by the administration of small doses of morphia in gum water or barley water. All food should be taken cold.

The treatment that we have indicated in the last two forms of hæmorrhage is intended for the exclusive guidance of emigrants or of others so placed as to be unable to summon prompt medical aid. Wherever this can be obtained no time should be lost in at once seeking it.

=Bleeding from the Nose.= Apply cold water containing ice, if obtainable. It should be so applied to the nose as to cause a shock. A cold piece of metal, such as a key, placed on the naked back sometimes stops the hæmorrhage. If neither of the above means succeed inject with a syringe a solution of alum or sulphate of zinc (ten grains to the ounce), or snuff up the nostrils some gallic acid, powder of pomegranate, kino, or catechu, mixed with starch. A plug of lint may also be dipped in either of the above solutions, or rolled in the powders, and pushed up the nostrils, or some tincture of perchloride of iron, properly diluted and applied on a piece of lint, may be tried.

=Bleeding from the Stomach.= _Syn._ HEMATEMESIS. In this case the blood is vomited usually in clots of a dark colour. It should be noticed whether it comes from the back of the nose or throat. The treatment consists in perfect repose in bed, and in the administration of dilute sulphuric acid in infusion of roses, with saline aperients. If these fail to give relief, tannin and krameria may be tried, and small doses of laudanum or five grains of alum may be given every four hours. If in pain, add to it 1/4 grain of acetate of morphia. All food and drinks should be taken cold, the latter iced. Pernitrate of iron in from 10 to 30 minim doses is a valuable remedy.

=BLENDE= (bl[)e]nd). A name applied to several minerals; appr., zinc-blend, or native sulphuret of zinc--the black jack of miners.

=BLIGHT= (bl[=i]te). See MILDEW, and PLANTS (Diseases of).

=BLIND'NESS= (bl[=i]nd'-). _Syn._ ABLEP'SIA, CÆ'CITAS, &c., L.; AVEUGLEMENT, CÉCITÉ, Fr.; BLINDHEIT, Ger. Deprivation or want of sight.

Blindness may be congenital, or born with a person; or it may arise from accident, external violence, or disease. In the latter it may frequently be relieved by medical and surgical treatment. See AMAUROSIS, CATARACT, EYES, OPHTHALMIA, VISION, &c.

=Blindness, Day.= _Syn._ NIGHT'-SIGHT; N[)Y]CTALO'PIA, L. A disease of the eye in which vision is painfully acute or more or less extinct in a strong light, as that of day; but clear and pleasant in the dusk of evening and at night. Its chief causes are excessive exposure of the eyes to the direct influence of very strong or glaring light, or to heat, or both of them together; and is often one of the sequelæ of ophthalmia (which _see_).

=Blindness, Night.= _Syn._ DAY'-SIGHT; HEMERALO'PIA, L. An affection of the eye, the reverse of the preceding, in which objects are clearly seen only in broad daylight. In the beginning of the complaint the patient continues to be able to see, though less clearly, for a short time after sunset, and even by moonlight, and perhaps distinctly by bright candle light; but after a short time this power is lost. It most frequently occurs in hot climates, and low latitudes at sea. Its chief causes are fatigue and exposure of the eyes to the glare of the tropical sun, probably coupled with gastric derangement. In some cases it is congenital, and is then generally incurable. The treatment consists in avoiding exciting causes, and endeavouring to restore the tone of the stomach, and the general health, by the usual methods. The eyes at the same time should be topically medicated by the frequent use of cold water, or mild astringent collyria. See OPHTHALMIA (Chronic).

=BLIS'TER.= _Syn._ PAP'ULA, PUS'TULA, L.; PUSTULE, VESSIE, &c., Fr.; BLASE, BLATTER, Ger. A bladder or vesicle caused by the deposition of serous fluid between the cuticle and the derma or true skin, occasioned by the application of a vesicant, or by a burn, scald, or friction.

=Blister.= _Syn._ VESICATO''RIUM, L.; EPISPASTIQUE, VESICATOIRE, Fr.; BLASEN-PFLASTER, B.-STOFF, Ger. A substance which vesicates or raises blisters; in pop. lang., a vesicating plaster or similar application.

The use of blisters is very ancient, and appears to date back long prior to the time of Hippocrates. Indeed, their value as cutaneous stimulants and counter-irritants appears to have been recognised by the medical faculty of all nations down to the present time. 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, as a state of excitement or irritation, in the same or a neighbouring part. In this way is explained the utility of blisters in local inflammation and spasmodic action, and it is this principle which regulates their application in pneumonia, gastritis, hepatitis, phrenitis, angina, rheumatism, colic, spasmodic affections of the stomach, &c.--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 frequently give relief in neuralgia, toothache, and other like 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.

Blisters are commonly prepared with cantharides plaster, or with some other preparation of cantharides; and, in the former case, usually have their surface sprinkled over with powdered Spanish fly; whilst the blistering surface is surrounded with a margin spread with common adhesive plaster, for the purpose of causing them to adhere to the part to which they are applied. In order to prevent the action of the cantharides upon the mucous membrane of the bladder, or urinary organs, they are also often sprinkled with a little powdered camphor, or better still, are moistened with camphorated ether, which, on its evaporation, leaves a thin layer of camphor on the surface; but care must be taken that the layer be not too thick, as in that case the plaster would not take effect. With a like object, a piece of thin book-muslin or tissue-paper (silver-paper) is frequently placed between the blistering surface of the plaster and the skin; the efficacy of which may be still further heightened by first soaking the muslin or paper in olive or almond oil.

The usual time an ordinary blister of cantharides plaster is allowed to remain in contact with the skin is from 10 to 12 hours. It is then gently removed. The subsequent treatment depends on the object in view. When it is not wished to maintain a discharge from the blistered surface, the vesicle is cut with the point of a pair of scissors at its most depending part, to let out the fluid which it contains, followed by a dressing of spermaceti or other simple ointment; but when the case requires the blister to be kept open, or to be converted into a perpetual blister, as it is sometimes called, the whole of the detached cuticle is carefully removed with the 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, as well as fabrics spread with them, have been brought before the public. These are noticed hereafter. See PLASTER, VESICANTS, &c.

=Blisters, Extempora''neous.= Among the best of these may be mentioned the following:--

1. A piece of lint dipped in the strongest vinegar of cantharides, and immediately after its application to the skin, covered over with a piece of strapping, or preferably a piece of sheet gutta percha or oiled silk, to prevent evaporation. Raises a blister in from 5 to 8 minutes.

2. Concentrated acetic acid, applied in the same way, has a similar effect.

3. (Dr Darcq.) Into a flat watch glass pour from 8 to 10 drops of highly concentrated liquor of ammonia; cover the liquid with a small piece of linen of rather less diameter than that of the glass, and at once apply this little apparatus to the previously shaved skin. The whole must be kept in its place by means of moderate pressure with the fingers, until a red ring, about 2 centimètres in breadth, is observed round the glass, when it is certain that vesication is effected. Sometimes scarcely 30 seconds are necessary for obtaining the result. The apparatus may then be removed, and the blistered part treated in the usual manner; the dressing being according to the object in view.

4. (Trousseau.) Bibulous paper slightly wetted with a little of the ethereal extract of cancharides, and instantly applied to the skin, the whole being covered with a piece of common adhesive plaster to prevent evaporation.

5. Boiling water applied by means of a suitably shaped tube, the adjacent parts being at the same time protected from injury. Instantaneous.

=Blister, Horse.= See VETERINARY MEDICINES.

=Blister*, Perpet'ual.= See BLISTER (_antè_).

=BLIS'TERING.= _Syn._ VES'ICANS, VESICATO''RIUS, L.; EPISPASTIQUE, VÉSICANT, VÉSICATOIRE, Fr.; BLASENZIEHEND, &c., Ger. In _medicine_, &c., that vesicates or raises blisters when applied to the skin.

=Blistering Pa'per, Plas'ter, Tis''sue= (t[)i]sh-[=u]), &c. See PLASTERS, VESICANTS, &c.

=BLOAT'ER.= See BLOTE.

=BLONDE.= [Fr.] _Syn._ BLOND'-LACE. Silk-lace. The name is now also applied to cotton-lace edged with silk. For the mode of cleaning it and getting it up, see LACE and MUSLIN.

=BLOOD= (bl[)u]d). _Syn._ SAN''GUIS, L.; SANG, Fr.; BLUT, Ger. The general circulating fluid of animals, and that on which the nourishment and growth of their bodies depend, and from which all the secretions are formed. It is warm and red in vertebrated animals; and, for the most part, cold and white in the invertebrata. In man and all other mammals, and in birds--the two highest classes of the animal kingdom--the blood, though collectively forming but one circulating stream, varies considerably in appearance according to the part or vessels in which it is found. That contained in the left side of the heart, and in the arteries, possesses a very brilliant scarlet colour, and is called arte''rial blood; whilst that found in the right side of the heart, and in the veins, has a darkish purple colour, and is called ve'nous blood. The two, however, differ little from each other in their chemical properties and composition; the most marked point of difference being that venous blood holds carbonic acid in solution, whilst oxygen predominates in the blood of the arteries. The fibrine of venous blood is also soluble in a solution of nitrate of potassa; whilst that of arterial blood is insoluble in that menstruum.

_Comp._ Blood consists of a transparent and nearly colourless fluid (plas'ma, se''rum, s[)e]ralbu'men), in which float about a countless multitude of microscopic round red bodies (blood-discs, blood-corpuscles), to which its colour is due, accompanied by a few colourless globules (white blood-corpuscles) of a somewhat larger size. The red corpuscles are found, on more minute examination, to consist of an envelope containing a solution of hæmatosin.

_Prop._ These are, for the most part, well known. It has an alkaline reaction, a saline and rather disagreeable sweetish taste, and when newly drawn evolves a peculiar odour or halitus, which almost immediately disappears. As it cools and on repose it coagulates, owing, according to some, to the spontaneous solidification of the fibrine.

The following table, based upon the observations of Schmidt and the analysis of Lehmann, is given by the latter, as representing the average quantitative relation of the principal constituents of normal blood. It will be noticed that the blood is here regarded as composed of two portions, one consisting solely of the red particles, and the other of the liquid, in which these red corpuscles are suspended, termed the _liquor sanguinis_, which consists of the serum holding fibre in solution:--

_Sp. gr. of Blood-corpuscles, 1·0885._

1000 parts blood-corpuscles contain--

Water 688·00
Solid constituents 312·00
consisting of--
Hæmatin (with iron) 16·75
Globulin and cell membrane 282·22
Fat 2·31
Extractive matters 2·60
Mineral substances (without
iron) 8·12
Chlorine 1·686
Sulphuric anhydride (SO_{3}) 0·066
Phosphoric anhydride (P_{2}O_{5}) 1·134
Potassium 3·328
Sodium 1·052
Oxygen 0·667
Calcium phosphate 0·114
Magnesium phosphate 0·073

_Sp. gr. of Liquor Sanguinis, 1·028._

1000 parts of liquor sanguinis contain--

Water 902·90
Solid constituents 97·10
consisting of--
Fibrin 4·05
Albumen 78·84
Fat 1·72
Extractive matters 3·94
Mineral substances 8·55
Chlorine 3·644
Sulphuric anhydride (SO_{3}) 0·115
Phosphoric anhydride (P_{2}O_{5}) 0·191
Potassium 0·323
Sodium 3·341
Oxygen 0·403
Calcium phosphate 0·311
Magnesium phosphate 0·222

The ash of blood contains about 6·84 per cent. of ferric oxide. (Lehmann.)

The following table gives the results of the average composition of human blood in man and woman, according to the analyses of Becquerel and Rodie:

Male. Female.
Specific gravity of defibrinated blood 1·0600 1·0575
" " of serum 1·0280 1·0274
Water 779·00 791·00
Fibrin 2·20 2·20
{ Serolin } { 0·02 } { 0·02
{ Phosphorised fat } { 0·49 } { 0·46
Fatty Matters { } 1·60 { } 1·62 {
{ Cholesterin } { 0·09 } { 0·09
{ Saponified fat } { 1·00 } { 1·05
Albumen 69·40 70·50
Blood-corpuscles 141·10 127·20
Extractive matters 6·80 7·40
------- -------
1000·10 1000·02
------- -------
{ Sodium chloride 3·10 3·90
Salts { Other soluble salts 2·50 2·90
{ Earthy phosphates 0·33 0·35
Metallic iron 0·57 0·54
----- -----
6·50 7·69

The blood also contains, in solution, oxygen, nitrogen, carbonic acid, as well as a free alkaline carbonate, urea, and small traces of alcohol have also been detected in normal blood.

The following report of a commission composed of MM. Mialhe, Mayel, Lefort, and Cornil, appointed to devise the best method for the examination of blood stains, was published in 1873. The following translation of the report appeared in the 'Chemical News' of December 5th, 1873.

1st. When the stain is of recent date, or supposed to be so, the red corpuscles should be particularly examined, and every care taken to preserve them without change. The stains must not be washed with water, so that the hæmatin may not be altered. After insisting on the microscopic characters of the blood stains, isolated or compared with those of various animals, the commission enumerates with care the fluids which are destructive or preservative of blood-corpuscles. Among the first, water, and particularly hot water, acetic, gallic, hydrochloric, and sulphuric acids; and of alkalies, potash and soda, even in weak solution, and ether and chloroform, also many other reagents, so alter the blood-corpuscles as to cause them to entirely disappear. Alcohol, chromic and picric acids, and bichromate of potash, preserve the corpuscles, though they alter their form. The preservative fluids are those whose composition approaches nearest to serum, such as the iodised serum of Schultze, an excellent preparation made with amniotic fluid, to which are added a few drops of the tincture of iodine, so as to give it the colour of white wine; or, better, a fluid composed thus; white of egg, 30 grams; distilled water, 270 grams; and chloride of sodium, 40 grams; or even a fluid containing 0·5 per cent. of chloride of sodium, or 5 or 6 per cent. of sulphate of sodium. If the stains be wetted and softened by these fluids, and then examined, white and red corpuscles and fibroid particles will be observed.

2nd. In more difficult cases, when the microscope, owing to the alterations which time has effected in the hæmatin, can give but vague information, examination by the spectroscope and chemical analysis enables us to arrive at precise results. The use of these means being less known, and also more delicate, requires special study.

1. _Spectrum analysis._ Colouring matters have the power of absorbing certain coloured rays of white light--the same always for the same substance. This is the principle upon which spectroscopic examination is based. If into any analysing tube filled with water a few drops of solution of hæmoglobin be introduced, till it has the colour of peach-blossoms, the luminous rays of the spectrum passing through this fluid present two bands of absorption, in the lines D and E of Frauenhofer, in the yellow and the green. The same fact would be observed if a few drops of blood were substituted for hæmoglobin in the analysis.

In a case of doubt the hæmoglobin of the blood could be reduced by adding to this latter a reducing body. Destroyed hæmoglobin has a different spectrum from oxygenated hæmoglobin, a single absorption band as large as the two former bands united, and a little to the left of Frauenhofer's line D.

2. In blood in a state of decomposition, or which has been treated with acids or caustic alkalies, hæmoglobin is changed into a new substance; hæmatin is formed, which, combined with hydrochloric acid, gives definite crystals.

In order to obtain them we must proceed thus:--A small fragment of dried blood is placed on a glass slide; it is dissolved in a drop of water, and a minute portion of sea-salt added. It is covered with a thin slide, and pure acetic acid is made to pass between the two slides, and it is heated over a spirit-lamp to boiling-point; acetic acid is again added, and it is heated afresh; and this is repeated till the crystals are obtained.

They are rhomboidal, of a dirty brown colour, quite characteristic, and require to be seen with a magnifying power of three hundred or four hundred diameters. With the smallest quantity of blood these two reactions can always be produced--the spectrum examination and the crystals of hydrochlorate of hæmatin; and they are so certain that the existence of one alone enables one to affirm the presence of blood.

3. The third process, though not so exact as the preceding, ought, nevertheless, never to be neglected. If to a very small quantity of blood dissolved in a little water be added a few drops of tincture of guaiacum and of binoxide of hydrogen, a persistent blue colour is immediately produced; but this very sensitive reaction can be obtained with other organic matter, such as nasal mucus, saliva, &c.; it therefore only gives a probability. We must proceed in the following manner:--A tincture of guaiacum is prepared with alcohol at 83 degrees, and guaiacum resin; a mixture of sulphuric ether and binoxide of hydrogen is also made, and enclosed in a stoppered bottle, and kept under water in the dark. This preparation is less liable to change than pure oxygenated waters. The object stained with blood, if it be white, is put into a little cup, then moistened with water to dissolve out the blood stain, and washed in distilled water; this water is then submitted to the action of these reagents.

If the thing stained be coloured, and the stain little or not at all visible, it must be moistened, and then pressed between two or three sheets of white blotting-paper, and tried first with the guaiacum. If the stain be of blood a reddish or brown spot will form on the paper.

One of the sheets should be treated with ammonia, and the stain will become crimson or green. A second sheet treated with tincture of guaiacum and ozonised ether will give a blue colour more or less intense, according to the quantity of the blood.

To recapitulate:--1. If the stains or scales of blood appear recent, the corpuscles may, after the necessary precautions, be examined under the microscope, and their presence, diameter, &c. observed, which will enable one to diagnose the origin of the blood, whether human or animal. 2. If the stains be old and the blood changed, the reaction with the tincture of guaiacum would make the presence of blood probable; but its actual presence cannot be affirmed without spectrum examination or the production of crystals of hydrochlorate of hæmatin; one of the two is sufficient. It is unnecessary to add that these reactions do not show whether the blood is human or animal.

Bullocks' blood has of late years, more especially in France, come into use as a remedy for anæmia and pulmonary phthisis. A correspondent, writing from Paris to the 'Medical Times and Gazette' in 1872, says: "It is a curious sight to see the number of patients of both sexes and of all ranks and ages, who flock to the slaughter-house every morning to drink of the still fuming blood of the oxen slaughtered for the table. I was struck with the facility with which young ladies take to it, and I have heard many say that they prefer it to cod-liver oil."

In a paper read in 1872 before the Academy of Sciences in Paris by M. Boussingault, detailing his researches into the composition of blood, the author expressed his surprise that bullock's blood was not more generally used as a food, as it contains all the constituents of a perfect aliment. According to the above chemist, of all nutritive substances the blood of animals contains the largest amount of iron. In man, Boussingault found in 100 grammes of blood 51 milligrammes of iron; in that of the ox, 55 milligrammes; of the pig, 59 milligrammes; and in that of the frog, 42 milligrammes. But it was not only in red blood that iron was found, Boussingault detected it in white blood also; and he found the blood of snails to contain as much iron as that of the ox or calf.

A simple and ingenious method for the therapeutic administration of the serum of the blood of sheep and oxen has been lately devised by Dr Francis Vacher, the medical officer of Birkenhead. Dr Vacher takes the blood of these animals, allows it to stand until it clots, removes the clot, and dries it at a gentle heat in a hot-air chamber. By this means he obtains a nearly odourless and comparatively tasteless powder, which is ten times the strength of fresh serum. To this preparation he gives the name "_serum sanguinis exsiccatum_." He believes that his dried serum will prove a valuable nutrient in consumption, scrofula, diabetes, and loss of flesh.

_Uses, &c._ That of bullocks is employed for the clarification of wines and syrups; also in the preparation of adhesive cements, as the vehicle in coarse paint for outdoor work, as a manure, as a bleaching powder, to make pure animal charcoal, and for several other purposes. The blood of sheep, pigs, and bullocks, mixed with flour or oatmeal, and seasoned, is eaten by the common people, but it is rather indigestible, and apt to induce disease. Gut-skins stuffed with this mixture form "black puddings."

Bullock's blood, dried by exposure in thin layers to a current of air, at a heat under 125°, and then reduced to powder, is exported in large quantities to the colonies, where it is used, as a 'clarifier,' in the sugar-works. Dried at a temperature ranging between 212° to 220°, then coarsely powdered, and the dusty portion sifted off, it is much used by fraudulent dealers to adulterate grain-musk. See CHARCOAL (ANIMAL), GLOBULIN, HÆMATOSIN, PLASMA, SERUM, STAINS, VISION, &c.

=Blood-purifying Tea, Gout and Rheumatic= (Franz Wilhelm, Neunkirchen). Equal parts of senna leaves, sarsaparilla root, liquorice, rad. tritici, red sandalwood, bittersweet stalks, cut small and mixed. (Hager.)

=Blood-purifying Tea= (F. Köller, Graz). Senna leaves, 32 parts; guaiacum wood, 10 parts; juniper wood, restharrow root, rad. tritici, dandelion root, chicory root, of each 8 parts; alder bark, 3 parts; sassafras, 2 parts; star-anise, 5 parts, dirty and worm-eaten, roughly chopped, and mixed. (Hager.)

=Blood, Spit'ting of.= See HÆMOPTYSIS.

=Blood, Vom'iting of.= See STOMACH DISEASES.

=BLOOD'-ROOT.= _Syn._ RED'-ROOT, PUCCOON'; SANGUINA''RIA, L. The _sanguin[=a]r'ia Canaden'sis_ (Linn.), a papaveraceous plant of North America; also its root (SANGUINA''RIA, Ph. U. S.), which is the part used in medicine. Juice, blood-red, used in dyeing. In small doses (3 to 5 gr.) it is stimulant, diaphoretic, and expectorant; in large ones (10 to 20 gr.), narcotic, emetic, and purgative. The powder is sometimes used as an escharotic. See SANGUINARINE.

=BLOOD'STONE.= A hard compact variety of hæmatite used to form burnishers. The name is also applied by lapidaries to the heliotrope.

=BLOOM.= In _perfumery_, &c., a name given to several calorific skin-cosmetics, of which the following are examples:--

=Bloom of Almonds= (ah'-m[)u]ndz). _Syn._ AL'MOND-BLOOM. _Prop._ Boil 1 _oz._ of ground Brazil-wood in 2-1/2 _pints_ of soft water for 30 minutes, adding the juice of two lemons towards the end; strain, and add 3/4 _oz._ of isinglass, 1/4 _oz._ of powdered cochineal, 1 _oz._ of alum, and 1/2 _oz._ of borax; boil again for 4 or 5 minutes, and strain through muslin. Glass or earthenware vessels must be used, as metals injure its colour.

=Bloom of Roses.= _Prep._ 1. Dried red rose leaves, 1-1/2 _oz._; boiling water, 1 _pint_; infuse in glass or earthenware for 2 hours, press out the liquor, and add the juice of 3 large lemons; the next day filter, or decant the clear portion. Both the above should be kept in a cool place, otherwise they soon spoil. A little spirit of wine (3 or 4 _fl. oz._ to the pint) is sometimes added to them to remove this objection. They are greatly inferior to the following:--

2. Carmine, 1/4 _oz._; strong liquor of ammonia (not weaker than ·900), 1 _oz._; put them into a stoppered bottle, set it in a cool place, and occasionally agitate it for two or three days, to effect a solution; then add of rose-water, 1 pint; and, after admixture, further add of esprit de rose, 1/2 _fl. oz._; pure rectified spirit, 1 _fl. oz._; again well agitate, and set the whole aside for a week; lastly, decant the clear portion from the dregs (if any), for use or sale. Very fine. A cheaper article is made by omitting a portion of the carmine, and the whole of the esprit and spirit; and a still inferior one by substituting 1-1/2 _oz._ of silver-grain cochineal (in powder) for the carmine, with digestion for a week in the ammonia previously diluted with one half of the water.

=Bloom of Youth, or Liquid Pearl= (G. W. Laird, New York). A colourless liquid holding in suspension 34 per cent. of zinc oxide entirely free from lead. (Chandler.)

=BLOTE.= To prepare or cure by drying and smoking; now only applied to fish.

=BLO'TER.= _Syn._ BLOAT'ER. A bloted fish; appr., a herring slightly salted, and only very slightly dried and smoked.

=BLOW'PIPE= (bl[=o]'-). _Syn._ CHALUMEAU, Fr.; LÖTHROHR, Ger. An instrument by means of which the flame of a candle or lamp, or a gas-jet, is directed upon any substance placed to receive it, which is thus subjected to an intense heat. The blowpipe is to the artist and the experimentalist what the wind-furnace is to the artisan; but it is proportionately more powerful, convenient, and economical.

Beginners are usually unable to maintain a continued stream of air from the jet of this instrument, although the doing so is really a very simple affair. The operation merely depends on a little artifice in using it, which is more difficult to describe than to acquire. The effect intended to be produced is a continual stream of air for many minutes, if necessary, without interruption, even for an instant. This is done by simply applying the tongue to the roof of the mouth, so as to interrupt the communication between the mouth and the passage of the nostrils; by which means the operator is at liberty to breathe through the nose, at the same time that by the muscles of the lips he forces a continued stream of air from the anterior part of the mouth through the blowpipe. When the mouth begins to be empty it is replenished by the lungs in an instant, while the tongue is withdrawn from the roof of the mouth, and replaced again in the same manner as in pronouncing the monosyllable tut. In this way the stream of air may be continued for a long time without fatigue, provided the flame be not urged too impetuously; and even should it be so urged no other inconvenience will be felt than that of slight fatigue of the muscles of the lips.

The hottest portion of the flame produced by the action of the blowpipe is at the tip of the outer white flame, which has also the property of rapidly burning or oxidising substances placed in it which are susceptible of such a change; and it is hence commonly called the OXIDISING FLAME. The interior blue flame is, for a like reason, called the DEOXIDISING or REDUCING FLAME, as it possesses the property of extracting oxygen from most bodies capable of being so affected.

Substances to be submitted to the action of the blowpipe-flame are placed on a support, which is either a piece of charcoal, or a wire or small spoon of platinum, gold, or silver, as the case may require. Sometimes a plate of cyanite is used. Pine-wood charcoal is preferred for this purpose; and the sides, not the ends of the fibres, are presented to the flame. When a very intense heat is required, the substance operated on should not exceed the size of half a peppercorn.

Several characteristic colour reactions may often be obtained in the examination of a substance for analysis, by fusing a small portion of it, with a bead of microcosmic salt, and exposing it for some time to the outer flame of the blowpipe. If the substance dissolve readily in the salt and rather copiously to a clear bead _whilst hot_, and is of a blue colour by candle light inclining to violet, it denotes COBALT. If it be green, upon cooling blue; in the reducing flame after cooling, red--COPPER. If green, particularly fine on cooling, unaltered in the reducing flame, CHROMIUM. If brownish red, on cooling light yellow or colourless; in this reducing flame, red whilst hot, yellow whilst cooling, then greenish--IRON. If reddish to brownish red, on cooling yellow to reddish yellow or colourless; in the reducing flame unaltered--NICKEL. If yellowish-brown, on cooling light yellow or colourless; in the reducing flame almost colourless, and blackish-grey on cooling--BISMUTH. If light yellowish to opal, when cold, rather dull; in the reducing flame whitish-grey--SILVER. If amethyst-red, especially on cooling; colourless in the reducing flame, not quite clear--MANGANESE. If the bead remains clear on cooling, ANTIMONY, ALUMINA, ZINC, CADMIUM, LEAD, LIME, and MAGNESIA are indicated, the latter five when added in somewhat large proportion to the microcosmic salt, give enamel white beads. The bead of oxide of LEAD saturated is yellowish. If the bead becomes enamel-white on cooling, even where only a small portion of the powder has been added to the microcosmic salt--BARYTA and STRONTIA are indicated.

If the substance dissolves in the microcosmic salt slowly and only in small quantity, the bead being colourless and remaining so after cooling, the undissolved portion looking semi-transparent, and if upon the addition of a little sesquioxide of iron it acquires the characteristic colour of an iron bead--this denotes SILICIC ACID.

For producing extreme degrees of heat the flame is blown with a jet of oxygen gas, the instrument being then called an OXYGEN BLOWPIPE; or a mixture of oxygen and hydrogen is burned, when it is called an OXY-HYDROGEN BLOWPIPE. The heat produced by the last is so great that no substance can stand exposure to it, even the most refractory native compounds being immediately fused. Gold is volatilised, and iron is rapidly consumed the instant it is placed in the flame.

1. Hemming's safety-jet for the oxy-hydrogen blowpipe.
_a_, Pipe conveying oxygen gas.
_b_, " hydrogen gas.
_c_, Ball
stuffed with fine wire-gauze.
_e_, Jet (internal diameter 1-80th of an
inch).
2. Black's blowpipe.
3. Bergman's "
4. Pepy's "
5. Wollaston's "
6. Oxy-hydrogen blowpipe.]

The principal varieties of the blowpipe in general use are figured in the engravings above.

Beside the above there are several other varieties of the blowpipe occasionally employed; one in which the air is expelled by the pressure of a column of water, and hence called the HYDROSTATIC BLOWPIPE; another, in which the flame is blown with the vapour of boiling alcohol, is named the SPIRIT-BLOWPIPE.

=Blowpipe, Herapath.= For sealing and bending glass tubes and constructing glass apparatus of various forms, it is convenient to have the blowpipe mounted on a fixed support, and when a flame of considerable power is required, the blast must be supplied by bellows worked with the foot. A very convenient form of blowpipe for these purposes is that invented by Herapath, and represented in the following figure, _a_ is a flexible tube attached to a stop-cock (_b_), which communicates with a tube (_c d_), bent at right angles at _d_, where a T-shaped tube (_e f g_) slips on by means of the piece _f_. The blow-pipe jet (_h i_) passes into the longer arm of the T-piece, and fits somewhat tightly; _k l_ is a second piece of flexible tube, terminating in a mouthpiece, or connected with a blowing apparatus. On turning on the gas, it passes in the direction marked by the arrows, and is to be inflamed at _e_. On blowing with the mouth, or by means of a pair of bellows, into the tube _k l_, the ignited gas takes the form of a blow-pipe flame of great power, the nature of which is entirely under control by means of the stop-cock _b_, and also by regulating the quantity of air supplied through the tube (_k l_). The T-shaped piece is movable at _f_, so that the jet may be directed to any position. The apparatus may be mounted on a heavy foot, and connected with the gas-supply, by means of the flexible tube, so that it can be placed in any required position on the laboratory table; or it may be permanently fixed on a table specially devoted to the purpose, and having beneath it a pair of bellows worked by a treadle.

A simple and inexpensive apparatus for supplying a continuous blast of air for blowpipe or other purpose is figured below.