Chapter C: W. HEATON, F.I.C., F.C.S., Lecturer on Chemistry at the (22)

This dark segment is bounded by a luminous arch of a blueish-white colour, which varies in breadth from 1 to 6 diameters of the moon, having the lower edge sharply defined, and the upper edge only when the breadth of the arch is small. This arch may be considered to be a part of a luminous ring, elevated at a considerable distance above the earth's surface and having its centre corresponding with some point near the north pole. The preceding description indicates the general features of the appearance of the aurora borealis; but several auroras have been described which presented striking peculiarities. Sometimes the phenomenon assumed the form of one or more curtains of light, depending from dingy clouds whose folds were agitated to and fro as if by the wind. Sometimes this curtain appeared to consist of separate ribbons of light, arranged side by side in groups of different lengths, and attaining their greatest brilliancy at the lower edges. In this country the aurora borealis seldom assumes the distinctness and brilliancy which characterise its appearance in northern latitudes, but the description thus given indicates the type to which such appearance of the meteor more or less approaches. During the winter that prevails in the northern hemispheres the inhabitants of the arctic zone are deprived for months together of the sun's light, and their long dreary night is relieved by the light emanating from this beautiful meteor, which shines with great frequency and brilliancy in those regions.

A remarkable connection has been observed between the aurora and the earth's magnetism, the magnetic needle showing great disturbance during a display of the aurora. The arches of the aurora most commonly traverse the sky at right angles to the magnetic meridian, though deviations from this direction are not rare. Sir J. Franklin found that the disturbance of the needle was not always proportionate to the agitation of the aurora, but was always greater when the quick motion and vivid light were observed to take place in a hazy atmosphere. The aurora is most frequent and vivid in high latitudes, towards either pole, but the meteor is not confined to these parts, as Dr Hooker states that one of the most brilliant displays he ever witnessed was under the tropical sky of India; and other observers have recorded instances of its appearance in the equatorial districts of the globe.

The attitude of the aurora varies considerably; there appears to be little doubt, however, that it frequently occurs at small elevations. Both Franklin and Parry record instances where it appeared below the level of the clouds, which they describe as having been hidden behind the masses of its light, and as reappearing when the meteor vanished. It would seem that there are two distinct kinds of aurora one dependent upon local causes, as in the cases last given, while in the other causes are probably cosmical, and the auroral effects are seen at very distant points of the earth's surface.

=AURORA POMADE.= For promoting the action of the skin. Cocoa butter with orris.

=AUTOG'ENOUS= (t[)o]j'-). _Syn._ AUTOGE''NEAL; AUTOG'ENUS (t[)o]j'). L. Self-generating or affecting; acting without the aid of foreign matter. In _anatomy_, &c., developed from distinct and independent centres; as parts or processes. Among _metallists_, it denotes a method of joining metals by fusing the parts in contact, by means of a flame of hydrogen, or of a mixture of hydrogen and common air, without the intervention of a fusible alloy or solder. Lead, and even ordinary hard solders, are, however, sometimes so employed, and the name, though improperly, retained.

=AUTOMAT'IC.= _Syn._ AUTOMATI'CUS, AUTOM'ATUS, L.; AUTOMATIQUE, Fr.; AUTOMATISCHE, Ger. Self-acting or self-moving, or that seems to be so; mechanical; of or resembling an automaton. In _physiology_, involuntary, applied to functions which are performed without the operation of the will; as the movements in respiration, the contractions and dilations of the heart, the persistent contraction of the sphincters, &c. In _mechanics_, &c., moving and acting from concealed machinery; also, as applied to _machinery_, self-regulating and directing, within the limits prescribed by its author, though moved by external power. To the last class belongs the self-acting machinery of our flax and cotton mills, our engineering establishments, &c.; in which the elemental powers are made to animate, as it were, millions of complex organs, infusing into forms of wood, iron, and brass, an agency resembling that of intelligent beings. The manufactures in which such machinery is employed are termed the AUTOMATIC ARTS.

=AUTOPSY.= Literally, personal observation or examination; ocular view. The term, however, is now applied, rather loosely, to a post-mortem investigation. A post-mortem may be performed with the object of endeavouring to ascertain the cause of death in a medico-legal inquiry, or in the furtherance of the study of pathology. It is also a preliminary to embalmment, and is sometimes had recourse to as a means of saving the child when a woman dies in full pregnancy.

In France no post-mortem examination is permitted to take place until at least 24 hours after death, this delay being enforced as a safeguard against the possibility of the body operated upon being still alive. In England no post-mortem can be made without the consent of the friends of the deceased, unless by warrant from a coroner; although in many public institutions this consent is dispensed with. Whenever, however, a prisoner dies in gaol an inquest and post-mortem are held on the body.

An autopsy is to be discouraged in cases where a person has died from infectious disease; but should the law require it to be undertaken, disinfectants both during and after the operation should be liberally had recourse to.

=AUTUMNAL FEVER.= This term is chiefly employed by American medical writers to designate typhoid fever, because of its prevalence in the autumn.

=AUXILION.= A packet of small plasters for the painless and radical cure of corns. Each plaster is to be worn for about a week, and then the horny pustule is to be removed with a sharp knife. The plaster is a compound of 1 part of resin plaster and 2 parts of lead plaster, and is likely to promote the removal and solution of the thick skin of the corns. (Hager.)

=AVA.= _Syn._ KAVA-KAVA. The native names of the root, a species of piper, the _piper methysticum_, cultivated in Tahiti, Hawaii, the Society and Tongan Islands, the natives of which make it into an intoxicating drink. It is said to have been used in France with excellent effect in gonorrh[oe]a; and a tincture of it has been strongly recommended both for external and internal administration in gout. "For medicinal purposes it is used in the form of infusion," a drachm of the scraped root being macerated in a quart of water for five minutes. Its action appears to vary with the amount taken; in small doses it is generally stated to act as a stimulant and tonic, but when taken in large doses it produces an intoxication which differs from that caused by alcohol, in being of a silent and drowsy nature accompanied by incoherent dreams" ('Pharmaceutical Journal,' August 19th, 1876, which consult for further information.')

=AVE'NA.= [L.] The oat; oats.

=AVE'NIN= (-n[)i]n). _Syn._ AVENA'INE* ([)a]v-e-) AVENI'NA, &c., L.; AVÉNINE, &c., Fr. A nitrogenous compound, analogous to, and probably identical with, casein, obtained from oats, and on which its nutritiveness chiefly depends.

_Prep._ The grain, reduced to the state of powder or meal, is washed on a sieve, and the milky liquid, after being allowed to deposit its starch, is heated to about 200° Fahr., to coagulate the albumen; when cold, acetic acid is added as long as a white powder falls, which is AVENIN; this is collected on a filter, drained, and dried by a gentle heat.

=AVEN'TURIN, Avant'urin= (-[=u]-r[)i]n; -v[)o]_ng_-t[=o][=o]--Knowles and Smart). [Eng. Fr.] A beautiful iridescent variety of rock crystal, minutely spangled throughout with yellow scales of mica (AVENTURIN, A. QUARTZ). A variety of felspar (A. FELSPAR) of somewhat similar appearance is found in the Continent and the Peninsula, of which the finer kinds are called A. ORIENTALE and PIERRE DE SOLEIL by the lapidaries. Both varieties are now imitated by the glass and porcelain manufacturers. See GLASS, GLAZE, PASTE, &c.

=A'VIARY= (-ve-). _Syn._ AVIA''RIUM, L.; VOLIÈRE, Fr.; VOGELHAUS, VOGELHECKE, Ger. A place for keeping birds; generally applied to an enclosed space or building in which birds are kept, or bred, on account of their rarity, plumage, or song; and not for food.

_Situa., &c._ For exotic birds, a place should be selected where the temperature can be maintained at a proper degree throughout the year, and which is well protected from the weather. This is commonly done by choosing a space attached to the summerhouse or hot-house. When the aviary is only intended for birds of climates similar to our own, any part of the open garden may be chosen, and a portion closed in, either with trellis-work or wire-work, or netting; care being taken to provide, in some easily accessible portion of it, full protection from vicissitudes of weather and season. Nor must cleanliness, and due ventilation and protection from foul air or noxious fumes, be left unattended to.

=AVIGNON' BERRIES= ([)a]v-veen-yo_ng_). French berries.

=AV'OIRDUPOIS'= ([)a]v-[)e]r-du-pois'). The common weight of 16 oz. or 7000 gr. to the lb., used in these realms for all kinds of goods, except jewelry and the precious metals, and medicines in dispensing, or as ordered in the 'British Pharmacop[oe]ia' of 1867.

=AX'IS.= [L., Eng., Fr.] _Syn._ AXE, Fr.; ACHSE, Ger. Primarily, that on or around which anything acts or performs; an axle or axle-tree. In _anatomy_, that on or around which any organ or part rests, gravitates, or centres. In _astronomy_, the diameter on or about which a celestial body revolves. In _botany_, part or parts about which particular organs are arranged; an imaginary line passing from the base to the apex of a pericarp &c. In _crystallography_, imaginary lines passing through the central points of a crystal, and about which the molecules or particles of matter composing it may be conceived to be symmetrically built up. In _geology_, the centre of a mountain-group. In _mechanics_, the straight line, real or imaginary, about which any body oscillates or revolves. See CRYSTAL, &c.

=AX'LE, Ax'le-tree= ([)a]ks'l). _Syn._ ESSIEU, Fr.; AXE (am rade), &c., Ger. In _mechanics_, the pin, rod, or material line, on which a wheel, &c., turns. See ANTI-ATTRITION, FRICTION, &c.

=AX'UNGE= (-[)u]nje). _Syn._ AXUN'GIA, L. _Primarily_, 'wheel-grease,' the lard or fat of an animal; restricted in _pharmacy_ to hog's lard.--AXUNGIA CURA'TA, A. PREPARA'TA, is prepared or washed hog's lard (which _see_).

=AYER'S PILLS.= Sold in long wooden boxes, each containing 25 pills, covered with sugar and starch, and composed of pepper, colocynth, gamboge, and aloes. (Hager.)

=AZADIRACHTA INDICA.= (Ind. Ph.) Nim or Margosa Tree. (Ind. Ph.) _Habitat._ Common throughout India; often cultivated in gardens. _Officinal parts._--1. The bark (_Azadirachtæ cortex_, Nim bark). It varies much in appearance, according to the size and age of the tree producing it. The bark from the trunk of a tree above three or four years of age is covered with a thick scaly epidermis, and varies in thickness from 1/4 to 1/2 inch. That from the smaller branches is smooth, of a dullish purple colour, marked by longitudinal lines of ash-coloured epidermis, from 1/8th to 1/12th of an inch apart. The inner layer of the bark, of a whitish colour in the fresh state, is powerfully bitter, far more so than the outer dark-coloured layer, which, however, possesses a greater amount of astringency. It contains a crystallisable principle (margosine) and an astringent principle (catechin).--2. The fresh leaves (_Azadirachtæ folia_, Nim leaves).--_Properties._ Bark astringent tonic and antiperiodic; leaves stimulant.--_Therapeutic uses._ In intermittent and other paroxysmal fevers, in general debility, and convalescence after febrile and other diseases, the bark has been employed with success. The leaves form a useful application to ulcers and skin diseases when a mild stimulant is required.--_Dose._ Of the powdered bark, a drachm three or four times a day.

_Preparations._ DECOCTION OF NIM BARK (Decoctum Azadirachtæ). Take of the inner layer of nim bark, bruised, 2 _oz._; water, a pint and a half. Boil for 15 minutes, and strain whilst hot.--_Dose._ As an antiperiodic, from 1-1/2 to 3 _fl. oz._, every second hour previous to an expected paroxysm. As a tonic, 1 or 2 _fl. oz._ twice or thrice daily. As this decoction soon decomposes in hot weather, it should be prepared fresh for use when required.

TINCTURE OF NIM BARK (_Tinctura Azadirachtæ_). Take of the inner layer of nim bark, bruised, 2-1/2 _oz._; proof spirit, 1 pint. Macerate for seven days in a closed vessel, with occasional agitation; strain, press, filter, and add sufficient proof spirit to make 1 pint. It may also be prepared by percolation in the same manner as Tincture of Calumba, q. v.--_Dose._ From 1/2 to 2 _fl. dr._ as a tonic.

POLTICE OF NIM LEAVES (Cataplasma Azadirachtæ). Take of fresh nim leaves a sufficiency; bruise and moisten with tepid water. A good stimulant application to indolent and ill-conditioned ulcers. Should it cause pain and irritation, as it sometimes does, equal parts of rice-flour and linseed-meal may be added. The bitter oil of the seeds is held in high repute by the natives as an anthelmintic, and as an external application in rheumatism. It is also said to be an insecticide.

=AZOERYTH'RYN= (-r[)i]th'-r[)i]n). A substance obtained, by Kane, from archil. It is insoluble in alcohol, ether, and water; but is very soluble in alkaline lyes, to which it imparts a port-wine colour.

=AZO'IC.= _Syn._ AZÖOT'IC; AZO'ICUS, AZÖOT'ICUS, &c., L. Lifeless; wholly destitute of organic life. In _geology_, &c., applied to strata which do not contain organic remains.

=AZOLIT'MIN= ([)a]z-o-l[)i]t'-m[)i]n). A dark-red substance obtained, by Kane, from litmus, of which it forms a large portion of the colouring matter. It is insoluble in alcohol, and in water unless alkalised.

=AZ'OTE*= ([)a]z'[=o]te; a'-z[=o]te). [Eng., Fr.] _Syn._ AZO'TUM*, L.; AZOT*, Ger. Nitrogen (because it is unfit for respiration, _i.e._ destroys life).

=AZOT'IC.= _Syn._ AZOT'ICUM, L.; AZOTIQUE, Fr.; AZOTISCH, Ger. Of or like azote, or containing it or formed from it; irrespirable; destructive to life.--AZOTIC ACID[dagger] is nitric acid; A. GAS[dagger], nitrogen.--AZO'TOUS ACID[dagger] was nitrous acid.

=AZ'OTISED= (-t[=i]zd). _Syn._ NITROGENISED, Containing azote or nitrogen; a common epithet of nitrogenous substances used as food.

=AZ'URE= ([)a]zh'-[=u]re; [=a]'zhure--Knowles, Smart, Walker). _Syn._ CÆRU'LEUM, L.; AZUR, Fr.; HELLBLAU, HIMMELBLAU, Ger. In _dyeing_ and _painting_, sky-blue; also the name of one or more pigments which possess this colour. See BLUE DYES, BLUE PIGMENTS, SMALTS, ULTRAMARINE, &c.

=AZ'URE-STONE.= Lapis lazuli.

=AZ'URITE= (-[=i]te). In _mineralogy_, lazulite; blue malachite; sometimes, lapis lazuli (the name being, unfortunately, very loosely applied by different writers).

=AZ'YMOUS[dagger]= (-e-m[)u]s). _Syn._ AZ'YMUS, L. Unleavened; unfermented; as sea-biscuit. Unleavened bread was formerly termed AZ'YME[dagger] (-e-me) and AZ'YMUS[dagger] by theologists.

=BAB'LAH.= The rind or shell of the fruit of _mimosa cineraria_. According to Dr Ure, it contains a considerable quantity of gallic acid, some tannin, a red colouring principle, and an azotised substance, and is the article imported from the East Indies and Senegal under the name of NEB-NEB.--Used as a cheap dye-stuff for various shades of drab and grey.

=BAC'CA= (b[)a]k'-[)a]). [L.; pl., bac'cæ, b[)a]k'-s[=e].] A berry.

=BACK.= [D., bak, a bowl or cistern.] _Syn._ BAC. In _brewing_, a large, open, flat reservoir or cistern; commonly that in which wort is cooled. In _distillation_, the vessel into which the wort is pumped from the coolers, in order to be 'worked' with yeast. The LIQUOR-BACK in a brewery, distillery, or rectifying house is the water reservoir or cistern.

=BACKS.= In the _leather trade_, the thickest and stoutest portion of the hide, used for sole-leather.

=BACON= (b[=a]'-kn). [W., baccun, prob. from Ger., bache, a wild sow; "old Fr., for dried flesh or pork"--Craig.] The flesh of swine salted and dried, and subsequently either smoked or not. The term is usually restricted to the sides and belly so prepared; the other parts of the animal having distinctive names. Sometimes, though rarely, the term is extended to the flesh of bears, and of other like animals, cured in a similar manner.

_Qual., &c._ When bacon has been properly prepared from young and well-fed animals, and is neither 'stale' nor 'rusty,' it forms a very wholesome and excellent article of food, especially adapted for a light or hasty meal, or as a relish for bread or vegetables. For persons with a weak stomach, and for invalids, great care should be taken to cook it without injuring its flavour, or rendering it indigestible. This is best effected by cutting it into slices of moderate thickness, and carefully broiling or toasting it; avoiding dressing it too hastily, too slowly, or too much. The common practice of cooking it in almost wafer-like slices, until it becomes brown and crisp, renders it not merely indigestible, but also a most fertile source of heartburn and dyspepsia. Fried bacon is remarkably strong, and is hence more likely to offend the stomach than when it is broiled, or preferably toasted before the fire; the last being, of all others, the best way of dressing it so as to preserve its delicacy and flavour. Gourmands, however, often esteem, as 'une bonne bouche,' bacon dressed in the flame arising from the dropping of its own fat.

_Choice._ Good bacon has a thin rind, and an agreeable odour, the fat has a firm consistence and a slightly reddish tinge; the lean is of a pleasing red colour, is tender, and adheres, whilst raw, strongly to the bone. When the fat is yellow, it is either 'rusty' or becoming so, and should be avoided. The streaky parts are not only those which are most esteemed, but are the most wholesome.

Bacon should be broiled or toasted in front of the fire. The rashers should be in thin slices, and the rind should be removed. The melted fat from the bacon should never be wasted. To partake of all broiled meats in perfection they should be served up as soon as they are taken off the gridiron.

=BACTERIUM= (BACTERION, a little rod). Since the publication of the researches of Professor Cohn, of Breslau, upon the nature of this organism, the idea previously entertained by Ehrenberg and others as to its animal origin has been long abandoned, and microscopists now very generally regard it as belonging to the vegetable kingdom. It is probably one of the lowest and most simple forms of vegetable or animal life, and consists of an envelope more or less enclosing protoplasm--the nitrogenous substance from which the cell nucleus is formed. Dr Lionel Beale very carefully crushed a very large bacterium while under observation by the microscope, and when the external membrane was ruptured the protoplasm was seen to escape, and to exhibit what Dr Beale regards as vital movement. In form, bacteria may be either globular, rod-shaped, egg-shaped, or filamentous. Cohn has described a variety presenting the appearance of beaded chains, or aggregations.

Bacteria vary considerably in size, some being as much as 1/3000th of an inch in length, whilst others are less than 1/10000th, and are only visible by the aid of a glass of very high power, such as the 1/50th of an inch objective. Dr Beale says, "The germs from which the little particles spring are far more minute and more difficult to identify. They appear as minute specks, the largest of them exhibiting a circular outline, and probably being spherical. The smallest are too minute to be discerned with the highest magnifying powers at our command. If a specimen of fluid in which these particles are rapidly growing and multiplying be carefully examined, many points will be observed to appear from time to time. After watching with great care for a considerable time a given spot I have assured myself that new particles actually come into existence; and that one does not, after intently watching for a time and concentrating the attention upon a certain space, merely see one coming into view one after another, as star after star. The material in which the minute germs of bacteria are imbedded, and which, at least in part, consists of formed material produced by the bacteria, is much softer than the matter of which the capsule of fungi consists. It is, perhaps, almost as soft as mucus. I believe that even the most minute bacterium germ is surrounded by a layer of such soft formed matter, in which very minute particles of bioplasm (protoplasm) divide and subdivide before they attain even the 1/100000th of an inch in diameter. When, therefore, bacteria in an early stage of development dry, it is not possible to identify them. When moistened, the dry mass swells up, and the bioplasm in the soft mucus-like matter grows, each particle producing a fresh investment of formed material, and then if the conditions are favorable, the germs either at once divide and subdivide for a time, or grow into perfect bacteria, which move freely and grow and multiply in this more advanced stage of development."

Bacteria increase by bisection, and when the surrounding conditions are favorable their rate of production is marvellous. It has been computed that an individual bacterium will generate nearly 17,000,000 of its fellows within twenty-four hours. The very probable vegetable origin and nature of bacteria insisted upon by Professor Cohn not only appears to derive great support from his researches into the metamorphoses they undergo during development, &c., but also from their behaviour with certain chemical reagents. For instance, it was found that boiling them in solution of potash had no effect, and also when treated with sulphuric acid and iodine they deported themselves somewhat as cellulin does under like circumstances; although from their extreme minuteness any changes that take place in their tissue are very difficult to observe. Another remarkable analogy presented between bacteria and plants is the manner in which they both assimilate the elements of which they are built up; for they derive their nitrogen not from previously existing albuminous compounds, but from ammonia.

They may be made to develop themselves in any fluid if the fluid contains an organic substance in which carbon is present, a nitrogenous substance which need not be organic, and a phosphate. They appear to derive their carbon by the decomposition of almost any substance, containing this element except carbonic acid, and they will obtain their nitrogen from a nitrate, the nitrate becoming reduced to the state of a nitrite. A knowledge of these facts will of course indicate the method to be followed if we wish to obtain bacteria. All that we have to do is to prepare a liquid that fulfils the conditions just stated. Dr J. Burdon Sanderson gives the following formula for one:--Phosphate of potassium 1/2 per cent., sulphate of magnesium, 1/2 per cent., dissolve in water having a trace of phosphate of calcium in suspension, and then add a per cent. of tartrate of ammonium, and boil the mixture. If properly boiled the liquid will be free from bacteria; but the contact of almost any organic substance, for example, a drop of water, a pinch of hay, a morsel of meal, &c., will cause their appearance.

The tenacity of life exhibited by the bacteria is extremely great. Dr Beale says, "Extreme dryness does not destroy them, and they withstand a temperature far below the freezing point; and that under adverse circumstances they remain dormant, and are not destroyed by a degree of heat which is fatal probably to every other living organism." Bastian says that the germs of bacteria are destroyed at a temperature of 160° F., but others are of opinion that under certain circumstances these germs are not killed at 212°, and that they may increase and multiply after having been exposed to this degree of heat. Professor Tyndall indeed has shown that in one experiment heating for a quarter of an hour at a temperature of 230° F. was insufficient to destroy them, whilst in another the five minutes' exposure of an atmosphere containing them to the incandescence of the voltaic current failed to kill them.

Cohn relates that manufacturers of pots of preserved peas at Lubek have since 1858 been obliged to cook them in a solution of 28 per cent. of salt, at a temperature of 226° F., to prevent the putrefaction of their contents, as in warm years nearly half the pots were found to be spoiled. In experiments made in conjunction with Dr Hare, Cohn found that in infusions boiled for less than fifteen minutes organisms were, without exceptions, developed. Somewhat lower temperature proved fatal to the great majority of bacteria. Those that survived were all found to belong to the genus _Bacillus_, and among _bacilli_ to the species _Bacillus subtilis_.

The experiments of Drs Ferrier and Burdon Sanderson would seem to show that bacteria do not nominally exist in the fluids and tissues of the body, but that their presence in the animal fluids may be traced to external surface contamination with ordinary water, the extent of their development being in proportion to the amount of the contamination. They contend that different varieties of water possess different degrees of what they term the 'zymotic power.' They examined the waters supplied by the several London water companies, and they found them to consist of varying degrees of bacterian impurity. They assert that all except freshly distilled water teems with invisible germs of bacteria. Writing of the universality of the presence of bacteria and bacterian germs, Dr Beale remarks:--"It would be difficult to say where bacterium germs do not exist. In air, in water, in the soil adhering to tiny particles of every kind, in every region of the earth, from the poles to the equator, they are found. In the substance of the tissues--nay, in the cells of almost all plants, and in the interstices of the tissues of many animals--bacteria germs exist. I know not what part of the body of man and the higher animals is entirely destitute of particles which under favorable circumstances develop into bacteria. Upon the skin and the surface of the mucous membranes they exist in profusion, and they abound in the mouth and in the follicles and glands."

Dr Eberth, of Zurich, states that he has found on ordinary sweat small oval-shaped bacteria which are frequently united in strings of two or three, and endowed with rather active movements. The author thinks that they very likely conduce to produce certain chemical modifications of sweat.

Drs Ferrier and Sanderson appear to have satisfactorily proved that fungi are not developed from microzymes, and that their apparent association is one of juxtaposition only. They give the following reasons for adopting this conclusion:--(1) The quick appearance of _torula_ cells in Pasteur's solution whenever it is exposed to the air, and the rapid development and luxuriant fructification of the higher form (_penicillium_) show that so far as the chemical composition of the liquid is concerned, there exist in it all the conditions favorable to the process. (2) When precautions are taken to prevent contamination by impure surfaces or liquids, the development which ends in _penicillium_ goes on from first to last without the appearance of microzymes. (3) Whenever it is possible to impregnate the test-liquid with microzymes, without at the same time introducing torula cells or germs, the development of the former begins and continues by itself without any transformation into the latter. Thus _fungi_ are not developed, notwithstanding the presence of microzymes in the same liquid in which, microzymes being absent, but air having access, they appear with the greatest readiness. As we have already seen the germs of bacteria exist largely in air; the experiments of Hiller, of Berlin, would seem to negative the theory of Ferrier and Sanderson, as they tend to show that bacteria have little influence on putrefaction.

We are indebted to Dr Lionel Beale for these illustrations, which are taken from his very interesting work on 'Disease Germs.'

Hiller's experiments tend to show that putrefaction is independent of the presence of bacteria, that bacteria can develop in liquids such as urine without producing its decomposition, and that the degree of their development and the rate of their multiplication depend upon the amount of assimilable material.

The following is the definition given to the word 'microzyme' (which occurs above) by its originator, Dr Sanderson: "I proposed the word 'microzyme' as a convenient general term for the first organic forms which present themselves in organic nitrogenous liquids when about to undergo spontaneous decomposition."

From the experiments of Béchamp it appears that under some circumstances the mother of vinegar, a conglomeration of microzymes, can be transformed into bacteria, and under other circumstances into a cellular ferment which can excite normal alcoholic fermentation in cane sugar. Subsequent researches have shown that the converse of this is also true, and that the cellular ferment may be transformed into microzymes and bacteria.

A mixture of starch and yeast kept at a temperature of 24° to 35° soon liquefies, and the yeast undergoes remarkable changes. The cells swell, become transparent, and gradually disappear. Myriads of microzymes of great agility spring into existence, then vibrios appear, and as these increase the microzymes diminish. The vibrios in their turn are succeeded by myriads of bacteria, and finally the bacteria disappear, leaving nothing but microzymes, single or coupled together. During these changes a small quantity of gas is disengaged, no butyric acid is formed, and but little acetic or lactic acids.

As then the mother of vinegar when changed into bacteria becomes lactic or butyric ferment, and when transformed into cellular matter becomes alcoholic ferment, and as beer yeast becomes lactic or butyric ferment when reduced to microzymes, vibrios, or bacteria, it is evident that the property of being a ferment of any particular nature does not depend essentially upon the nature of the ferment, but upon its organisation or structure.

A contributor to the 'Medical Times and Gazette' of February 2nd, 1878, advances the opinion that many of the bacteria are only parts of a plant which has other forms and other modes of growth and propagation when not confined to the living organism or to fluids, and regards the bacterium as a transitional or provisional and not as a permanent form, but an abnormal phase of life thrust upon the plant by accident.

=BACTERIA AS ORIGINATORS OF DISEASE.=--The researches of many eminent microscopists and physiologists afford abundant evidence of the presence of bacteria in the blood of persons affected with various infectious diseases. For instance, Core and Feltz, of Strasbourg, found a linked bacterium in the blood of those attacked with septicæmia, typhoid, and puerperal fevers. The same investigators also discovered bacteria in the blood of patients suffering from scarlet fever; this blood when injected into the veins of rabbits set up a feverish disease that proved fatal.

Again, in the blood of man and the sheep attacked with smallpox, a bacterium of the globular or sphere-shaped variety was found by Keber, Hallier, and Zurn.

Bacteria have also been found in the blood during measles, and in the splenic apoplexy of sheep and cattle. They have likewise been identified in diphtheritical exudations both from the kidneys and womb, as well as in the blood during an attack of rheumatic fever, and they are undoubtedly present in the same fluid during many feverish disorders. Drs Lewis and Cunningham failed to discover them in the blood of cholera patients. Professors Cohn and Koch stand prominently forward as the advocates of the germ theory of disease by bacteria. Professor Cohn divides the bacteria into groups, genera, and species, and assigns to each species a different function.

For instance, he considers the ferment of contagion to be due to the presence of a variety of the sphere-shaped bacterium--one of his groups. He divides the whole group into three--the chromogen, zymogen, and pathogen, the bacteria of pigmentation, of fermentation, and of contagion, respectively. He says those organisms are exceedingly minute, darkish or coloured granules, so small as to be immeasurable. They frequently present the appearance of beaded chains or the form of aggregations. They are motionless and are occasionally found with the _Bacterium termo_ in putrefying organic liquids.

Messrs Chauveau and Sanderson have discovered a bacterium in vaccine lymph which believers in the germ theory class among the pathogen bacteria, and which they have named the _Micrococcus vaccinæ_. Amongst the pathogen bacteria they also include the _Micrococcus dipthericus_ and _Micrococcus septicus_, the former found in the epithelium of certain organs during certain forms of pyæmia, and the latter in the miliary eruption of typhus, pyæmia, and other diseases. The chromogen or pigmentary bacteria have occasionally been the means of working miracles. Several instances of bread exuding blood, under supernatural circumstances, are related by Rivola. Ehrenberg found this colour on some bread in the house of a patient who had died of cholera, and he ascertained the pigment to be due to the presence of the _Monas prodigiosa_, small round bodies which Professor Cohn classes with the micrococci, a variety of the sphere-shaped bacterium.

The recent investigations of Koch were directed to the cause of splenic fever, and Cohn on examining his specimens found that they were examples of Bacteria of the species called _Bacillus anthracis_, which seems to present little or no difference to the _Bacillus subtilis_ of hay infusions. Koch found that _bacilli_ increase with enormous rapidity in the blood, and in the fluid of tissues of living animals, by developing in length and dividing transversely. The animals employed were chiefly mice, and a small incision being made at the root of the tail, as minute a drop as possible of the fluid containing the _bacilli_ was injected into the system. The spleen invariably became enormously swollen, and filled with a large number of crystalline-looking rods of varying size, never exhibiting movement or spore formation; they increased in numbers solely by division. The number of _bacilli_ found in the blood varies in different animals; thus in the guinea-pig it was enormous, sometimes exceeding that of the blood-corpuscles; in the rabbit much smaller, so that sometimes several drops had to be examined before any were found, in the mouse often _nil_. In the blood of dead animals or other suitable fluids the _bacilli_ grow to very long straight leptothorax-like filaments (within certain limits of temperature, and with the presence of air), while the formation of numerous spores goes on at the same time.

Kohl believes that it is to the presence of the spores that the occurrence of splenetic fever appears to be referable. When living, inoculation with them always produced the disease; but if killed, as by drying, or a high temperature, inoculation failed; it was necessary either that living spores should be present, or that the filaments should be capable of generating spores, in order that the disease should be propagated by inoculation.

Koch tried whether the poisonous bacilli spores could gain entrance through the digestive organs, but found that mice and rabbits could eat them with impunity. Koch draws attention to the similarity of splenic fever to typhus and cholera. He says it presents analogies to typhus in its dependence on soil-water, its preference for low grounds, its sporadic occurrence throughout the year, and its development into an epidemic in the late summer and autumn. Like cholera, again, he says, it is connected with soil-water, and it also agrees with cholera in the point which has been so well made out by Pettenkofer, that on board ship an interval of three or four weeks is sufficient to prevent its further development.

Hence Koch is disposed to hope that the contagium of typhus and cholera may still be discovered in the form of some _Schizophyte_ or spheroidal bacterium, though practical observers have hitherto sought for them in vain.

Many pathologists, however, refuse to accept the accuracy of these deductions, and regard the presence of bacteria in the blood and tissues during disease as of no significance; whilst they deny that it is satisfactorily proved that they are the cause of disease.

Dr Lionel Beale says:--"Changes in the processes of digestion are soon followed by the multiplication of bacteria in every part of the alimentary canal, and within a few hours countless millions may be developed. They multiply in the secretions under certain circumstances, almost as soon as these are formed, and I have adduced evidence to show that bacteria germs exist even in healthy blood. In the very substance of some cells I have seen them, and in many cases in which little granules have been discerned in connection with bioplasts. There is reason to believe that some of them are really bacteria germs, passive as long as the higher life is maintained in its integrity, but ready to grow and multiply the instant a change favorable to them, and adverse to us, shall occur."

And again he remarks:--"Bacteria prey upon morbid structure, and upon the substances resulting from the death of bioplasm (protoplasm). We ought not, therefore, to be surprised at their existence in disease. They are found in great numbers amongst pus-corpuscles which have ceased to live, and they grow and multiply with great rapidity in fluids which contain disease germs, as soon as these begin to lose their specific powers and to undergo decomposition." See GERMS.

=BAD''GER= (b[)a]j'-[)e]r). _Syn._ ME'LES, L.; BLAIREAU, Fr.; DACHS, Ger. The _ur'sus me'les_ (Linn.), one of the plantigrade carnivora, a burrowing nocturnal animal, common in Europe, Asia, and North America. Since the extirpation of the bear, the badger is the sole representative of the ursine family in our indigenous zoology. Its habits are "nocturnal, inoffensive, and slothful; its food consists of roots, earth-nuts, fruits, the eggs of birds, insects, reptiles, and the smaller quadrupeds; its noxious qualities are consequently few and of slight moment, and by no means justify the exterminating war unintermittently waged against it." (Brande.) Its "muscular strength is great, its bite proverbially powerful; and a dog must be trained and encouraged to enter willingly into combat" with it. (Id.)

_Uses, &c._ The flesh of the badger is prized as food; the skin used for pistol furniture; the hair made into brushes. The American badger is commonly called the GROUND-HOG. The Cape badger produces HYRACEUM (which _see_).

=BAD'IANE= (-e-[)a]hn). [Fr.] _Syn._ BAD'IAN, B.-SEED. Star-anise seed.

=BADI''GEON= (b[)a]-d[)i]zh'[=o]ne; b[)a]d'-e-zh[)u]n[double-dagger], or b[)a]-d[)i]j'[)u]n[double-dagger]--Smart). Among operatives and artists, any cement used to fill up holes and to cover defects in their work. Among statuaries, a mixture of plaster and free-stone is commonly used for this purpose; among joiners and carpenters, a mixture of sawdust and glue, or of whiting and glue; and among coopers, one of tallow and chalk. The name is also given to a stone-coloured mixture used for the fronts of houses, and said to be composed of wood-dust and lime, slaked together, stone powder, and a little ochre, umber, or sienna; the whole being mixed up with weak alum water to the consistence of paint, and laid on in dry weather.

=BAEL.= [Nat.] _Syn._ INDIAN BAEL, BEL*; BAEL, B. IN'DICUS, BE'LA, B. IN'DICA, L. The _[oe]g'le marmelos_ (Correa; _cratæva m._, Linn.) one of the Aurantiaceæ (DC.). Dried half-ripe fruit imported from the E. Indies, under the name of INDIAN BAEL. Astringent and refrigerant; highly extolled in chronic dysentery, diarrh[oe]a, English cholera, and relaxations generally. It is also used in bilious fevers, hypochondriasis, melancholia, &c. Root-bark, stem-bark, and expressed juice of the leaves, particularly the first, also used in the same cases in India. Ripe fruit fragrant and delicious; used, in the E. I., as a warm cathartic, and regarded as a certain cure for habitual costiveness. Mucus of the seeds used by painters as size; also as a cement. Unripe fruit used to dye yellow. It is generally administered under the form of DECOCTION or EXTRACT (which _see_).

=BAGASSE'= (-g[)a]s'). [Fr.] The dry refuse stalks of the sugar cane as they leave the crushing-mill.--Used as fuel in the colonial sugar-houses.

=BAGG'ING.= The cloth or materials of which bags or sacks are made. In _agriculture_, applied to a method of reaping corn by a chopping, instead of a drawing cut. See RATS, &c.

=BAHIA POWDER.= See ARAROBA.

=BAHR'S NON-POISONOUS MEDICAL SNUFF.= A snuff largely advertised in the Berlin journals, composed chiefly of powdered galls. (Hager.)

=BAIN-MARIE.= [Fr.] In _old chemistry_, a water bath; also, sometimes, a sand bath. In _cookery_, a shallow vessel containing heated water, in which saucepans, &c., are placed, when it is necessary either to make them hot, or to keep them so, without allowing them to boil. It is extremely useful in making sauces, warming soups and small dishes, and when dinners are delayed after they are ready to be served.

=BA''KING= (b[=a]ke'-). _Syn._ ACTION DE CUIRE AU FOUR, Fr. The process of cooking, or of heating, drying, and hardening any substance in an oven or kiln, or by the rays of the sun; the art or trade of a baker[double-dagger]; also technically, a batch or ovenful, or the quantity baked at once (= FOURNÉE, Fr.).

In _cookery_, baking is, perhaps, of all others, the cheapest, most convenient, and best way of dressing dinners for small families, where a good domestic oven is at hand. Though the flavour of baked meat is generally considered barely equal to that of the same parts roasted, there are some joints and dishes to which it appears particularly suitable. Among these may be mentioned legs and loins of pork, legs and shoulders of mutton, fillets of veal, &c. A baked pig, if it has been occasionally basted, and the heat has not been too great, eats equal to a roast one. Geese and ducks treated in the same way are also excellent. A baked hare which has been basted with raw milk and butter also eats well; and so do various pieces of beef, especially the buttock. Cooks tell us that this last should be sprinkled with a little salt for a day or two before dressing it, and after being washed is preferably baked, along with about a pint of water, in a glazed earthen pan tied over with writing paper, 'three or four times thick.' A baked ham is said to be preferable to a boiled one; to be tenderer, fuller of gravy, and finer flavoured. It should be soaked in water for about an hour, wiped dry, and covered with a coarse thin paste or batter. Ordinary dishes require similar treatment in baking to that given them when roasted.

For domestic use, where the kitchen-range does not include a really good oven, the portable articles known as a 'DUTCH-OVEN,' and an 'American oven,' form an excellent substitute, admirably adapted for small joints, poultry, &c., all of which, when these utensils are skilfully employed, possess a delicacy and flavour fully equal to the same when roasted; whilst not more than one half the fire is required for the purpose. According to Miss Acton they also "answer excellently for delicate sweet puddings, and for cakes." See BREAD, CAKES, ROASTING, &c.

=Baking Pow'der.= See POWDERS.

=Baking Powder, American.= For making light pastry. Tartaric acid and chalk. (Reichardt.)

=Baking Powder, Borwick's German=, is an artificial fermentation powder, compounded with coarse maize-flour. (Gädike.)

=Baking Powder, Goodall's=, is a compound of 2 parts of rice flour with 1 part of a mixture of tartaric acid and bicarbonate of soda. (K. Boschan.)

=Baking Powder or Yeast Powder, Professor Horsford's= (Cambridge, U.S.). This is a powder supplied in two packets. The one contains an acid phosphate of lime and magnesia made up with a certain quantity of flour, and the other is bicarbonate of soda, with a little chloride of potassium.

=BAL'ANCE.= As in the process of what is termed gravimetric analysis the chemist has to determine the weights of the different substances employed as well as found, it will be self-evident that for his results to be trustworthy the balance he employs must be perfectly accurate and reliable.

The accompanying drawing, from Roscoe, represents a common form of chemical balance.

The apparatus consists of a perforated brass beam (AA), vibrating about its centre, at which is fixed a triangular knife-edge of agate (C); this rests upon a horizontal agate plane attached to the upright brass pillar. To each end of the beam light brass pans (BB) are hung, each pan being suspended by an agate plane, upon an agate knife-edge fixed on the end of the beam at DD. This arrangement is rendered necessary in order to reduce as much as possible the friction of the edges on their supports, which friction, if unchecked, would seriously impair the sensibility of the balance.

In order to prevent the agate edges being worn away by constantly rubbing on the agate planes, the beam and the ends (DD) are supported by the brass arm (EE), when the balance is not in use, so that the agate surfaces are not in contact. The beam and pans are released when required by turning the handle (F). The movement of the brass arm (EE) is accompanied by means of a rod descending through the upright brass pillar, and resting on a simple eccentric, by the turning of which by the handle (F) it may be gradually raised or lowered. The substance to be weighed (held by a tube, watch glass, &c.) is placed in one of the pans, and weights added one by one in the other, until the beam is in equilibrium: this is ascertained by the long pointer(G) oscillating to an equal distance on each side of the central mark or index, this latter being subdivided into equal spaces, so that the oscillations can be measured. A spirit level is also a necessary appendage to the instrument, since it enables the operator to place the beam on an exactly horizontal level.

The beam of the balance is generally graduated into decimals. This saves the trouble of placing a weight on the scale, since it enables the operator to weigh the milligramme and its fractions by suspending a centigramme rider or hook on or between the indicated points of a graduated line.

The balance is enclosed in a glass case, which serves not only to protect it from dust, but to allow of the weighing being carried on away from the outer air, in which the prevalence of draughts proves a source of considerable annoyance to the weigher. The front of the scale case generally consists of three parts, viz. a fixed centre piece and two lateral frames or doors, all of course of glass. It is of importance that the air inside the balance case should be perfectly dry, since a humid atmosphere would not only affect the weight of many hygroscopic substances when placed in the pans, but likewise be liable to attack the instrument itself. To guard against these casualties a small beaker containing oil of vitriol, or chloride of calcium, or freshly-burnt lime, should be kept in the case. A balance capable of weighing 70 or 80 grammes in each scale will be found to meet the needs of most chemists.

Fresenius says, "The ACCURACY of a balance depends upon the following conditions:

"_a._ The fulcrum must be placed above the centre of gravity of the beam.

"_b._ The suspension points of the scales must be on an exact level with the fulcrum.

"_c._ The beam must be sufficiently strong and inflexible to bear without bending the greatest weight that the construction of the balance admits of.

"_d._ The arms of the balance must be of equal length; _i.e._ the points of suspension must be equidistant from the fulcrum or point of support.

"The SENSIBILITY or DELICACY of a balance depends upon the following conditions:

"_a._ The friction of the edges upon their supports must be as slight as possible.

"_b._ The centre of gravity must be as near as possible to the fulcrum.

"_c._ The beam must be as light as possible."

The following are the tests given by the same authority for the accuracy and sensibility of a balance:

"1. The balance is in the first place accurately adjusted, if necessary, either by the regulating screws, or by means of tinfoil, and a milligramme weight is then placed in one of the scales. A good and practically useful balance must turn distinctly with this weight; a delicate chemical balance should indicate the one tenth of a milligramme with perfect distinctness.

"2. Both scales are loaded with the maximum weight the construction of the balance will admit of; the balance is then _accurately_ adjusted, and a milligramme added to the weight in one scale. This ought to cause the balance to turn to the same extent as in 1. In most balances, however, it shows somewhat less on the index.

"3. The balance is accurately adjusted should it be necessary to establish a perfect equilibrium between the scales by loading the one with a minute portion of tinfoil (this tinfoil must be left remaining upon the scale during the experiment); both scales are then equally loaded, say with about fifty grammes each, and if necessary the balance is again adjusted (by the addition of small weights, &c.). The load of the two scales is then interchanged, so as to transfer that of the right scale to the left, and _vice versâ_. A balance with perfectly equal arms must maintain its absolute equilibrium upon the interchange of the weights of the two scales.

"4. The balance is accurately adjusted; it is then arrested, subsequently set in motion, and again allowed to recover its equilibrium; the same process should be repeated several times. A good balance must invariably reassume its original equilibrium.

"A balance of which the end edges afford too much play to the hook resting upon them, so as to allow the latter slightly to alter its position, will show perceptible differences in different trials. This fault, however, is possible only with balances of defective construction.

"A balance to be perfectly useful for the purposes of quantitative analysis _must_ stand the first, second, and last of these tests. A slight inequality of the arms is of no great consequence, since this may be readily and completely remedied by the manner of weighing." See WEIGHTS.

=Balance, Hydrostat'ic.= See SPECIFIC GRAVITY.

=Balance, Tor'sion.= A delicate instrument, invented by Coulomb, for measuring the intensities of the electrical and magnetic forces.

=BALD'NESS= (bawld'-). _Syn._ CAL'VITAS, CALVI''TIES (v[)i]sh'-e-[=e]z), L.; CALVITIE, CHAUVETÉ, Fr.; KAHLHEIT, KAHLKOPF, KAHLKÖPFIGHEIT, Ger. Primarily, absence or loss of any natural covering; appr., destitution or loss of hair, more especially of that of the top and fore-part of the head. In _botany_, absence of beard or awn.

Grey hair and baldness dependent on old age are natural consequences of man's infirmity, and must be regarded as evidence of failing vigour, rather than in the light of a disease. Premature loss of hair may be induced by various causes. It is common after severe fevers, and is frequently caused by external pressure, friction, or violence, and by such other local actions and conditions which, when long continued, interrupt the normal functions of the skin. Persons with a consumptive, scorbutic, scrofulous, or syphilitic taint, or of a general bad habit of body, frequently lose their hair early. In these cases it probably arises from debility or paralysis of the cutaneous vessels, and the consequent insufficient nutrition of the hair-bulbs. When it occurs in persons under the middle age, and apparently enjoying good health, it may be often traced to the pernicious practice of constantly wearing a hard non-ventilating hat, or to disordered stomach, habitual smoking or hard drinking, irregular habits, or late hours. Excessive anxiety or grief, and intense study and thoughtfulness, also tend to promote the early decay of the hair. The natural baldness of the aged, and frequently the premature baldness of earlier years, arises from the gradual attenuation of the scalp, which ultimately becomes too thin to afford room for the performance of the functions of the hair-producing organs, and too scantily supplied with blood for their due nutrition and support.[104]

[Footnote 104: In such cases it will be found that, owing to this attenuation, the scalp covers a larger portion of the skull than previously; and that its sides have somewhat receded from the top of the head, so that the roots of the remaining hair descend lower towards the forehead, temples, and back of the neck, than when the parts were in vigorous health. This may be perceived by applying the open hand to the part, and then gently closing the fingers, when the scalp may be drawn into its original position, and will then appear loose and wrinkled over the occiput, &c.; and this in a manner very different to what occurs when the top of the head is covered, or well-covered, with hair.]

_Treatm._ The baldness of senility and that arising from the permanent injury or destruction of the hair-bulbs, admit of no cure, notwithstanding the daily assurances of advertising impostors to the contrary. In other cases, when a disposition to baldness exists, shown by the hair falling off in large quantities, or ceasing to grow with its usual vigour and rapidity, the frequent but gentle use of the hair-brush, and of any bland stimulating oil, pomade, or wash, if adopted in time, will generally prove sufficient to arrest the progress of decay, and, very frequently, to restore the hair to its pristine condition. The head may be advantageously washed in cold water, at least once a day; or what is better, a shower bath may be taken on rising in the morning. Should this plan not succeed, the head, or the upper part of it, may be shaved, and a wig, or a scalp, adopted for a time. The effect of keeping the hair closely cropped or shaved is to make it grow thicker, stiffer, and stronger, and this often when all other means fail.