Cooley's Cyclopaedia of Practical Receipts Volume I Part 192

The vegetable kingdom contributes spores, pollen, cells, cotton fibre, and the germs of vibriones and monads. Besides these are many living creatures, brought by the agency of monsoons and cyclones from extensive deserts. Showers of sand derived from these wastes occur in different parts of Europe. Ehrenberg submitted the sand obtained during seventy of these showers to microscopic examination, and found, in addition to sand and oxide of iron, numerous organic forms, amongst which 194 Polygastrica, 145 Phylolithariae, besides Polythalmia, &c. Silvestre found four species of diatoms and living infusoria in the sand obtained from a dust shower in Sicily in 1872. But, besides the presence of these organisms in the external air, which may be regarded exceptional, it contains, under ordinary conditions, numerous living creatures, some brought into it from the earth by the force of winds, others growing in it. More than 200 forms--rhizopods, tardigrades, and Anguilulae--have been found in it by Ehrenberg. So tenacious of life are these latter that, even if dried, they will retain their vitality for months, and even years.

Of the organisms found in the air the following are the most important:--1. Extremely small, round, and oval cells, which, that they may be rightly examined by the microscope, require a power of 600 or 1000 diameters. They are found sometimes growing together and sometimes cleaving, when they present an appearance like the figure 8. Sulphuretted hydrogen in the air is said to stimulate their growth and carbolic acid to check it. Although existing in the open air, they are by far more abundant in the atmosphere of dirty prisons. They are also met with in the sweat of the prisoners inhabiting these localities. Observers believe they increase rapidly by cleavage. No ill effects have been traced to them.

"To the same cla.s.s, perhaps, of these round and oval cells the bacteria and monads, which have been described as gathered from the air, must be a.s.signed; the development of these cells into vibriones and rod-like bacteria, though a.s.serted, has not yet been definitely proved, and, indeed, Burden-Sanderson's observations rather throw doubt on the statement that true bacteria exist in the air.

"2. Spores of fungi are not infrequent in the open air; they occur most commonly in the summer (July and August); they are not in this country more frequent with one wind than another; the largest number found by Maddox in ten hours was 250 spores; on some days not a spore can be found.

Maddox leaves undetermined the kind of fungus which the spores developed under cultivation; the spores were pale or olive coloured and oval, probably from some form of s.m.u.t. Angus Smith found in water through which the air of Manchester was drawn innumerable spores. Mr Dancer has calculated that in a single drop of the water 250,000 fungoid spores as well as mycelium were present; but as the water was not examined for some time there may have been growth. Mycelium of fungus seems uncommon in the air, but is sometimes found.

The cells of the _Protococcus pluvialis_ are not uncommon, neither, perhaps, are those of other algae. On the whole the experiments of Maddox show that in his locality (near Southampton) it is incorrect to speak of the air being loaded with fungoid spores; they can be found, but are not very numerous."[267]

[Footnote 267: Parkes.]

Amongst other suspended matters are minute fragments of dried horse droppings, derived from the original substance, reduced to powder by the traffic, and carried by aerial currents into the atmosphere. In the 'Chemical News' for October, 1871, Professor Tichborne gives the results of some a.n.a.lyses of the street dust of Dublin. Some dust taken from the top of a pillar 134 feet high contained 297 per cent. of organic matter, whilst that collected from the street consisted of as much as 452 per cent. This organic matter was princ.i.p.ally composed of comminuted stable manure; it was capable of acting as a ferment, and was possessed of deoxidising powers sufficient to reduce nitrate to nitrite of potash.

This evidence of the presence of suspended known matters in the air has led some pathologists to conjecture that certain formless substances found in it, undeterminable by the microscope, may in reality be disease germs, which, being transported through long distances by the wind, may also be the means of spreading certain maladies from one locality to another. In this manner cholera has been supposed to have been propagated from India, the particles of the dried excreta of cholera patients being supposed to be the carriers of the formidable disease; this hypothesis of its origin, however, is not yet, at any rate, universally accepted. "In the case of smallpox and scarlet fever the distance to which the 'contagions' spread by means of the air is certainly inconsiderable."[268]

[Footnote 268: Ibid.]

Hitherto we have spoken only of the nature of the dust occurring in the external air. The composition of that met with in confined s.p.a.ces is, of course, largely influenced by surrounding conditions and circ.u.mstances; for instance, in indifferently ventilated apartments, in addition to the substances already enumerated, the dust of the confined air has been found to contain small particles of food, bits of the hair of human beings, domestic animals, and feathers of birds, as well as of coals, cinders, charred wood, linen, cotton, and wool fibres, varieties of epithelium, and certain round cells resembling nuclei.

In the apartments of the sick it is additionally charged with a very large quant.i.ty of organic matter.

The spores of the Tricophyton and Acorion have been discovered in and seem peculiar to skin hospitals. In that taken upon two occasions from the ward of St. Louis (the Skin Hospital of Paris), and submitted to examination, one specimen was found additionally to contain 36 per cent. and in the other 46 per cent. of organic matter.

"The scaly and round epithelia found in most rooms are in large quant.i.ty in hospital wards, and probably in cases where there is much expectoration and exposure of pus or puriform fluids to the air the quant.i.ty would be still larger."[269]

[Footnote 269: Parkes.]

The investigation of the air of a cholera ward in 1849 by Britain and Swayne, at Clifton, revealed the presence of bodies resembling fungi; minute scales of variolous matter have been found by Bakewell in smallpox wards, and cells of pus and epithelium in the sheds and stables of animals affected with cattle disease and pleuro-pneumonia. Dr Watson detected in the air of a ward for consumptive patients at Netley, together with pus cells, bodies bearing a great resemblance to the cells met with in tuberculous matter, these latter not being discoverable in the open air or in the rooms of non-consumptive persons; whilst Rainy, examining the air of the cholera ward at St. Thomas's Hospital, found bacteria in it, besides fungi. The presence of these bodies was, however, detected in the open air.

The atmosphere of mines, workshops, manufactories, and rooms in which handicraft of any kind is carried on, is more or less laden with small particles of substances employed in the arts, manufactures, and various industries. The nature of these floating substances, as well as a list of the diseases, together with the amount of mortality they produce, will be found under the article "TRADES, CERTAIN, THEIR EFFECTS ON HEALTH."

Dr Wynter Blyth gives the following instructions for collecting atmospheric dust for examination:--

"The most simple way to obtain the emanations from a sick room for microscopical observation is to suspend a common water bottle from the ceiling filled with iced water. The moisture of the air condenses, and brings with it organic matters; or the moisture may be gathered which adheres to panes of gla.s.s in cold weather; or a bottle may be taken containing some distilled water, absolutely free from impurities of any kind, and filled several times with the air of the place. The water may then be submitted to microscopical and chemical examination.

"Metallic dust, such as iron, may be attracted by a magnet. The most usual and successful way is, however, by _aspiration_, either by an aspirator made for the purpose [see ASPIRATOR], or by means of an ordinary cask, by which a considerable volume of air is drawn through a small quant.i.ty of distilled water, glycerin, or other liquid. The indirect way for the organic matter, &c., mentioned above, viz., a.n.a.lysis of the rain water, and the obvious way of collecting the dust, by carefully sweeping it off shelves, &c., may be also enumerated.

"_Examination of dust._ The dust obtained by any or all of these methods should now be examined microscopically and chemically. Low powers should be used at first, and then (if looking for germs) the highest that can be obtained. If the dust is in any quant.i.ty it can be submitted to chemical examination, but a knowledge of what cla.s.s it belongs to--animal, mineral, or vegetable--is sufficient for most purposes."[270]

[Footnote 270: 'Dictionary of Hygiene.']

=DUST-BIN.= A dust-bin on any premises may become a nuisance and a peril to health if certain precautions are not observed with respect to it.

It should have a tolerably tight-fitting cover, and one that is waterproof also, if, especially as it ought to be, the dust-bin is situated in the open air. The bottom should never be the bare earth, but one that is properly bricked or tiled. It should be lime-washed occasionally, in summer time the most frequently. Only dry refuse, such as ashes and the sweepings of rooms, &c., should be thrown into it.

On no account should fragments of vegetable or animal nature be put in, such as fishbones, potato parings, cabbage stalks, dirty or discarded pieces of apparel, or bits of rags or dusters. These should be at once burnt on the kitchen fire; the best kind of stove for consuming these is that known as the kilnhouse. Meat bones should be got disposed of as soon as possible, as they frequently give rise to unpleasant and offensive odours. Finally, the dust-bin should not be too large. If too capacious, it acts as a guile for servants not to have it cleaned out as often as it should be, the frequent removal of its contents being a most essential condition toward the preservation of health.

=DUSTING.= This very important branch of household labour is sometimes very inefficiently performed. Very frequently the dust of an apartment is not removed, but merely disturbed or driven from one place to settle down on another.

It should always as much as possible be got rid of by means of a duster or a brush and dust-pan.

As the dust should adhere to the former, this should from time to time be taken out into the open air and shaken. During the time a room is being dusted the furniture should be collected in as small a s.p.a.ce as possible, and enveloped in the dusting-sheet. The dusting-sheet on its removal should be carefully folded together, taken into the air and shaken. The furniture may then be dusted and returned to the proper places.

A duster should never be rubbed over furniture standing close to a wall, or a dirty mark on the wall-paper will be the result. The same caution applies to mantel-pieces, where the paper may soon be spoilt by the act of dusting, unless contact with the duster be avoided.

=DUTCH DROPS.= The dark-coloured residue left by the dry distillation of turpentine. (Hager.)

=DUTCH GOLD.= See ALLOY.

=DUTCH LIQ'UID.= See OLEFIANT GAS.

=DYE'ING.= The act of tinging or colouring absorbent materials by impregnating them with solutions of colouring matters or dye-stuffs. The colouring matters which impart their tints without the intervention of other substances are called 'substantive colours'; while those which require such aid are called 'adjective colours.' The bodies employed to fix and develop the latter cla.s.s are called 'mordants.' The exact way in which dye-stuffs act upon fibrous materials has not yet been investigated as fully as it deserves; the generally received opinion is that the fibre has a chemical affinity for the colouring matter in the case of substantive dyes, and likewise for the mordant, which, in its turn, has an affinity for the colouring matter of adjective dyes. Another opinion is that the fibres have pores, which, when expanded by heat or chemical agents, admit particles of colouring matter. However this may be, it is certain that different materials 'take' dyes in different proportions; thus, silk and wool take the coal-tar dyes in the most perfect manner, but cotton requires the intervention of a most powerful mineral or animal mordant. Wool takes the colouring matters of most dye-stuff so well that the deepest tints can readily be produced. SILK and COTTON are dyed with greater difficulty, whilst LINEN shows still less disposition to take dyes. The operations which take place in dyeing are 'mordanting,'

'ageing,' 'dunging,' 'dyeing,' and 'clearing.' The first of these operations is noticed under MORDANT. After the fabric has been mordanted, it is generally hung up in a room through which a current of steam and air is pa.s.sing, by means of which the union between the fibre and the mordant is quickened very considerably. This exposure to moist air is the step in the process to which the term 'ageing' is applied. The operations of 'dunging' and 'clearing' are noticed above (see DUNGING). The 'dyeing'

proper, which follows the 'dunging,' is effected by running the fabric through the solution of the dye-stuff, the colour being modified more or less by the nature of the mordant used. Under the names of the different colours the means used to dye such colours are minutely described. See BLACK DYE, BLUE DYE, &c.

The following particulars respecting the production of the more common colours may prove interesting to the reader, who merely requires some general information on the subject:--

BLACK is usually produced by logwood or galls with an iron mordant. Common black silks are dyed with logwood and fustic, iron being used as a mordant. The best silks are dyed black on a blue ground. Woollen goods are first dyed blue with indigo, and afterwards with sumac, logwood, and green or blue copperas. Cotton and linen goods are dyed black in a very similar manner.

BLUE is commonly produced from indigo, either in the form of sulphate or in aqueous solution. Prussian blue, with a persalt of iron or tin as a mordant, gives a very splendid dark blue. Of late several blues of novel shades have been produced from coal-tar.

RED is obtained in various shades by using cochineal, safflower, lac-dye, madder, or logwood, with a tin mordant.

PURPLE. Until the last few years the dyer was dependent for his purples on orchil or cudbear, but he has now at his disposal the magnificent series of aniline, or coal-tar, colours, ranging from the most delicate violet, or 'mauve,' to the full crimson-purple, known as 'magenta.' See PURPLE DYE.

YELLOW. The most important yellow dyes are made from quercitron, fustic, turmeric, arnotto, and French and Persian berries. For further information, see BLEACHING, CALICO-PRINTING, &c.

=DYER'S SPIRITS.= See TIN MORDANTS.

=DYES.= See DYEING, and the names of the princ.i.p.al colours.

=DYE-STUFFS.= The colouring materials used in dyeing are so called. The more important of them are noticed under the respective names.

=DYNAMITE.= n.o.bel's dynamite consists of a mixture of 75 parts of nitroglycerin incorporated with 25 parts of an infusorial earth known as 'kieselghur,' found at Luneburgh, and consisting of the fossil sh.e.l.ls of infusoria. Kieselghur is almost pure silica. Dynamite is in regular use on the Continent for mining operations, and its manufacture and transport appear to be subject only to reasonable precautions. If ignited in the open air, or even when loosely packed, it burns quietly away, with the evolution of a small quant.i.ty of nitrous acid. Although the first cost of dynamite is four times that of gunpowder, it is said to be really only half as expensive, since it possesses eight times the explosive power of the latter; added to which the labour of boring blast-holes is avoided. It also possesses the advantage of not being impaired in efficiency by damp.

When required for use the dynamite is rammed into a thick paper cartridge, into which a fusee is pa.s.sed, by means of which it is ignited. Although dynamite when once made may be comparatively harmless until exploded at will; that great risk is incurred in its manufacture may be inferred from the fact that, upon two occasions the manufactory on the Continent in which it is prepared has been twice entirely destroyed. On the occasion of the last accident it was impossible to learn the cause of the disaster, since every one in the building was blown to atoms.

Diralin is said to be a mixture of nitroglycerin with sawdust or wood-pulp as used in paper-mills, the two latter substances having been previously treated with nitric and sulphuric acids.

=DYNAMOM.= (Dr Momma Dusseldorf.) A galvano-electric curative apparatus. A small capsule of horn, containing a disc secured to a pedicel. On the disc a number of sharp needles are fixed. By gently moving the apparatus, and afterwards withdrawing it, artificial pores are produced in the skin by punctures which are not very painful. These are then to be rubbed with a certain oil, probably containing cantharides. (Wittstein.)

=DYS'ENTERY.= _Syn._ b.l.o.o.d.y FLUX; DYSENTERIA, L. A disease arising from inflammation of the mucous membrane of the large intestines, and characterised by stools consisting chiefly of blood and mucus, or other morbid matter, accompanied with griping of the bowels, and followed by tenesmus. There is generally more or less fever, and the natural faeces are either retained or discharged in small, hard b.a.l.l.s (_scybala_). The common causes of this disease are marsh miasma, improper diet, excessive exhaustion, and fatigue, and, above all, exposure to the cold and damp air of night after a hot day.

_Treat._ The common dysentery of this country generally gives way to gentle aperients (castor oil or salts-and-manna), to cleanse the bowels, followed by mild opiates or morphia, to allay irritation. The chronic symptoms, which frequently hang about for some time, are best combated by mild tonics and vegetable bitters (bark, calumba, cascarilla).

Occasionally, chalybeates (ammonia-citrate of iron, lactate of iron, wine of iron, saccharine carbonate of iron) will be found useful during convalescence. Throughout, the diet should be light and nutritious.

The contagious dysentery, of camps and hot climates, is a severe and often fatal disease, in which the preceding symptoms are complicated with remittent or typhoid fever. Its treatment is tedious and difficult, and depends chiefly on judiciously meeting the several symptoms as they develop themselves. Aperients, diaph.o.r.etics, and nauseants, followed by tonics, are the remedies generally relied on. The febrile symptoms must be treated according to their inflammatory or putrid tendency. This variety of the disease frequently gives rise to organic diseases of the abdominal viscera, dropsy, &c. It is regarded by some as contagious, but without sufficient reason.