Chapter XXIII: Front Matter (23)

=NUTRI′′TION.= The phenomena of life are accompanied by the constant and unceasing waste of the materials of which the animal body is composed. Every act of volition, every exertion of muscular power, every functional action of the organism, whether perceptible or imperceptible and involuntary, every play of chemical affinity and decomposition, even thought itself, occasions the disorganisation and destruction, as living matter, of a portion of ourselves. But the process of respiration, and the various important changes with which it is connected, tends, more than all the other vital functions, to waste the substance of the body, the temperature of which it is its special office to support. This loss, this change, which commences with life and terminates only with death, is compensated for by the constant renewal of the whole frame by the deposition and assimilation, or organisation, of matter from the blood, which thus becomes gradually thinner and impoverished, unless, in its turn, it receives a corresponding supply of its vital elements. This it does from the food, which, by the functions of digestion, is converted into a ‘chyle,’ and after being taken up by the ‘lacteals,’ passes into the blood, of which it then becomes a part, and after being animalised and rendered similar to the being it is destined to nourish, by the peculiar action of the vital affinities, it attaches itself to those organs or tissues, the loss of which it is intended to supply. This constitutes nutrition.

The food of animals, or, rather, the nutritious portion of that food on which we live, is wholly organic matter, and is either directly or indirectly produced by the powers of vegetation from the inorganic world. The plant elaborates food for the herbivora, and these, in their turn, serve as food for the flesh-eating animals. In both cases the leading alimentary principles are the same; the difference is in their proportions. Flesh is identical in composition with blood, and with the body of the animal that blood is destined to nourish. It abounds in albumen, casein, and fibrin. The vegetable substances used as food also contain nitrogenised principles of a precisely similar character and chemical constitution to those found in flesh, and which we are, therefore, bound to believe are absolutely the same. The gluten of wheat, when purified from gliadin, presents all the characteristics of pure fibrin. The albumen extracted from vegetable juices, when coagulated by heat, cannot be distinguished from the boiled white of egg in a divided condition. The legumen or vegetable casein of almonds, peas, beans, and many of the oily seeds, bears the most striking resemblance to the casein of milk. These facts clearly show that the leading nitrogenised principles of animal bodies pre-exist in vegetables, and that the substances employed as food must have the same, or nearly the same, chemical composition as the body itself. The striking contrast of animal and vegetable food, as far as this point is concerned, is more apparent than real. The actual difference between the two is to be found in the existence of a large quantity of non-nitrogenised matter (sugar, starch, &c.) in the last, which is not contained in the other——matter which abounds in carbon, and which, by its combustion in the system, serves to support the animal heat at a less sacrifice of the organic fabric. In the flesh-eating animal the waste of the organic tissues is very rapid, and the tax upon the vital energies proportionate; for the temperature of its body is kept up, for the most part, by the burning of the nitrogenised matter of which these tissues are composed.

The process of digestion is that by which the available portions of the food are reduced to a form adapted for absorption by the vessels by which it is introduced into the system. In the flesh-eating animal this process is extremely simple, and consists in the mere comminution of the food by the teeth, and its reduction to the liquid state in the stomach, after which, from the nature of its composition, it is nearly all taken up, and at once conveyed into the blood. In the herbivora, however, the process of digestion is much more complicated, and occupies a longer period. Besides the ordinary principles of flesh, their food contains starch, sugar, gum, &c., mixed with much inert vegetable fibre and other useless substances, from which it must be separated. The first of these supply materials for the waste and growth of the body, the second meet the requirements of respiration, and the last pass unaltered through the alimentary canal.

The nature of the digestive process is not clearly established. The principal objects effected appear to be the conversion of starch, coagulated albumen, fibrin, casein, &c., into a liquid form. It is known that the saliva contains a peculiar principle (ptyalin) resembling diastase, capable of transmuting starch into sugar, and that when a little starch is held in the mouth for a short time this change actually occurs. It is also known that the gastric juice contains a peculiar organic principle named ‘pepsin,’ and that this substance, in conjunction with dilute hydrochloric acid, which is likewise present in the stomach, possesses the property of dissolving the albuminous principles of food. (See PEPSIN.) These changes occur whenever these conditions are established out of the body, and hence it is inferred that the process of digestion is effected by similar means. Of this, however, there is no direct evidence.

The use of food, as already noticed, is twofold. It supplies the materials of nutrition to balance the waste of the tissues continually taking place in the body, and it conveys into the system those elements which, by their chemical combinations, produce heat. To effect this purpose in the most beneficial manner, the food should not only be sufficient in quantity, but the proportions of its nitrogenised and carbonaceous principles should bear such relations to each other as to amply meet the demands of the system for each, without the existence, however, of an undue excess of either.

When the muscular movements of a healthy animal are restrained, a genial temperature kept up, and an ample supply of food containing much amylaceous or oily matter given, an accumulation of fat in the system rapidly takes place; this is well seen in the case of stall-fed cattle. On the other hand, when food is deficient, and much exercise is taken, emaciation results. These effects are ascribed to differences in the activity of the respiratory function. In the first instance, the heat-food is supplied faster than it is consumed, and hence accumulates in the form of fat; in the second, the conditions are reversed, and the creature is kept in a state of leanness by its rapid consumption. The fat of an animal appears to be the provision of nature for the maintenance of life during a certain period under circumstances of privation. Hence it is that a lean animal suffers more from cold than a fat one, and is also sooner starved.

“The origin of fat in the animal body has recently been made the subject of much animated discussion; on the one hand, it was contended that satisfactory evidence exists of the conversion of starch and saccharine substances into fat, by separation of carbon and oxygen, the change somewhat resembling that of the vinous fermentation; it was argued, on the other side, that oily or fatty matter is invariably present in the food supplied to the domestic animals, and that this fat is merely absorbed and deposited in the body in a slightly modified state. The question has now been decided in favour of the first of these views, which was enunciated by Professor Liebig, by the very chemist who formerly advocated the second opinion. By a series of very beautiful experiments, MM. Dumas and Milne-Edwards proved that bees exclusively feeding upon sugar were still capable of producing wax, which was pointed out as a veritable fact.”

Professor Liebig divided the principles found in food into two classes:——plastic elements of nutrition, or flesh-and-blood-making principles; and elements of respiration, or those which, by their decomposition or combustion in the system, generate heat. They are as follows:——

_Elements of Nutrition._ | _Elements of Respiration._
|
(Plastic or Nitrogenous.) | (Heat-producing.)
———————— | ————————
Animal flesh | Fat
Blood | Starch
Vegetable albumen | Gum
Vegetable casein | Cane sugar
Vegetable fibrin | Grape sugar
| Milk sugar
| Pectin sugar
| Alcohol

This division is in the main warranted by fact, but, no doubt, the nitrogenous elements of food produce heat as well as the non-nitrogenous.

=NUX VOMICA.= _Syn._ KOOCHLA NUT, POISON N., VOMIT N.; NUCES VOMICÆ, NUX VOMICA (B. P., Ph., L., E., & D.), L. “The seed of _Strychnos Nux vomica_, Linn.” (Ph. L.), imported from the East Indies (B. P.). This drug is chiefly known as a violent excitant of the cerebro-spinal system. In small doses, frequently repeated, it is tonic, diuretic, and, occasionally, laxative; in slightly larger ones, it is emetic; and, in large doses, it is an energetic and fearful poison.——_Dose_, 1 to 3 gr.; in paralysis, nervous affections, impotence, chronic dysentery, chronic diarrhœa, &c. Its frequent use is said to render the system proof against the poison of serpents. See STRYCHNINE, its active principle.

=OAK.= The British oak is the _Quercus Robur_ of Linnæus, of which there are two varieties, _Q. peduncata_ and _Q. sessiflora_. The wood of the oak is more durable than that of any other tree, and “for at once supporting a weight, resisting a strain, and not splintering by a cannon shot, it is superior to every other kind.” It, nevertheless, “warps and twists much in drying; and, in seasoning, shrinks about 1-32nd of its width.” Foreign oak is less durable, but more brittle and workable. The bark (OAK BARK; QUERCÛS CORTEX, QUERCUS——B. P., Ph. L., E., & D.) is used as an astringent and febrifuge, in doses of 30 to 120 gr., frequently; an astringent decoction is also made of it, but its chief employment is in tanning leather. The peculiar appearance of old oak or ‘wainscoting’ is given to the new wood by exposing it, whilst very slightly damp, to the fumes of ammonia.

=OAT.= _Syn._ AVENA, L. The common cultivated oat is the _Avena sativa_ (Linn.), a graminaceous plant, of which there are several varieties, as the _Avena sativa alba_, or white oat; _A. s. nigra_, or black oat; the potato oat, &c. Other species are also cultivated, as _Avena nuda_ (Linn.), pilcorn, or naked oat; _A. strigosa_, or Spanish oat, &c. The seed (OATS; CARYOPSIDES, SEMINA AVENÆ CRUDA) form the common horse-corn of this country, but in the northern parts of the country it is extensively used as food for man. The husked grain constitutes GROATS, and its meal OATMEAL. The latter does not form a dough with water, as wheaten meal or flour does.

Oats consist of from 24% to 28% of husk, and 74% to 78% of grain. According to M. Payen, they contain of starch, 60·59%; azotised matter, 14·39%; saccharine and gummy matter, 9·25%; fatty matter, 5·50%; cellulose, 7·60%; silica and saline matter, 3·25%. The husks contain between 6 and 7% of saline matter. (Prof. Norton.) The ash amounts to 2·18%, and consists of potassa and soda, 26·18%; lime, 5·95%; magnesia, 9·95%; oxide of iron, ·40%; phosphoric acid, 43·84%; sulphuric acid, 10·45%; chlorine,·26%; silica, 2·67%; alumina, ·06%. (Johnston.)

The yield of oats is from 20 bushels per acre in poor soils, up to 60, 70, and even 80 bushels per acre in rich soils. The weight per bushel varies from 35 to 45 lbs., and the product in meal is about one half the weight of the oats.

A large proportion of the oats given to horses passes off undigested. It has hence been proposed to prevent this loss, by either coarsely bruising them in a mill, or by pouring boiling water over them, and allowing them to macerate till cold, when they are to be given to the horses without straining off the water. It is stated on good authority that oats thus treated will not only fatten quicker, but go twice as far as without preparation. Oat bruisers are now manufactured by most agricultural implement makers.

Under the microscope the oat is seen to consist of two or three envelopes; the outer being composed of longitudinal cells; the second obliquely transverse and not very clearly seen; in this, the cells are wanting in part or pass into the cells of the third coat; the third envelope consists of a layer, usually single, of cells, like wheat. Before the envelopes are searched for the husks must be removed. The starch-cells are small, many sided, and cohere into round composite bodies, which are very characteristic, and which, by pressure, may be divided into separate grains. A high power is necessary for the examination of these latter. The starch of the oat does not polarise light.

=OAT′MEAL.= _Syn._ AVENÆ FARINA, F. EX SEMINIBUS AVENÆ (Ph. D), L.

Oatmeal is the grain of the oat deprived of the skin, kiln-dried, and afterwards ground. It is regarded as one of the most nutritious of our cereals, being rich in nitrogenous matter, fat, starch, and sugar. According to Letheby it contains in 100 parts:——

Nitrogenous matter 12·6
Carbo-hydrates 63·8
Fatty matter 5·6
Saline matter 3·0
Water 15·0
——————
100·0

Kreusler has shown that the nitrogenous principle of oatmeal contains gluten-casein, a substance very similar to the legumin of peas and beans. Letheby points out that, although it contains more nutrient material than wheat, its higher price renders it less economical as an article of diet. Oatmeal forms the staple of the food of the farm labourer both in Scotland and in England, being consumed more largely by the Scotch than the English peasant. Scotch oatmeal is superior to English in nutritive value. Oatmeal, when mixed with water, does not possess sufficient tenacity to enable it to be made into bread. It can, however, be baked into excellent cakes, which, when made in Yorkshire, are leavened, and when in Scotland, unleavened.

The qualities of indigestibility and a tendency to produce irritability of the bowels and skin, have been ascribed to oatmeal; before it was so prepared as to effectually remove from it the husk and hairs by efficient screening, it was in Scotland a frequent source of intestinal concretion. These concretions, the nature of which was unravelled by Dr Wollaston, consisted principally of phosphate of lime mixed with the hairs and husks of the oat.

Of thirty samples of oatmeal examined by the ‘Lancet Sanitary Commissioner,’ no fewer than sixteen samples, or more than one half, were adulterated. The substance generally used for this purpose is barley meal, which is only half the price of oatmeal. Husks of barley, wheat, and of the oat itself, are also frequently used. Rice and maize are also sometimes added. That supplied to the army, navy, and the workhouses, was very commonly adulterated with whiting, plaster of Paris, or ground bones. The mineral sophisticant may be detected by the excess of ash, which should not exceed 2·36 per cent. These frauds are readily detected by the microscope.

_Grits_ or _Groats_ are the decorticated grain of the oat, which when bruised or crushed constitute Embden groats. Flummery (known in Scotland as _sowans_) is made by steeping the husks of the grain in water, until they become slightly sour, the strained liquid being boiled down to the consistence of gruel. Oatmeal soon becomes sour and rancid. It should be purchased at such shops as have a quick sale for it. See ACARI, STIR-ABOUT.

=OBE′′SITY.= _Syn._ OBESITAS, POLYSARCA, L. Unhealthy or troublesome fatness or corpulency. Sometimes the secretion of fat, and its accumulation in the adipose membrane, is almost as rapid as that of water in anasarca; on which account some of the old writers have called obesity a dropsy of fat. Persons in easy circumstances, of indolent habits, who live freely, and who are of a cheerful and contented deposition, are those most liable to obesity. The treatment consists in the very gradual reduction of the diet, until it falls rather below the average quantity required by a healthy adult; the very gradual disuse of fermented liquors, more especially beer; the gradual abridgment of the time devoted to repose, until it does not exceed 5 or 6 hours; the employment of several hours daily in exercise in the open air, at first moderate, but increased day by day in energy, until it becomes laborious; and, lastly, arousing the mind from a state of lethargy to one of active or even harassing employment.

In some cases the accumulation of fat has been enormous. Bright, of Maldon, weighed 728 lbs.; Daniel Lambert, of Leicester, 739 lbs.; a girl, 4 years old, noticed in the ‘Phil. Trans.,’ 1813, weighed 256 lbs.

Persons affected with obesity are generally short-lived.

=OBSTRUCTION OF LOCAL AUTHORITY.= Various penalties are mentioned in different sections of the Public Health Act for the offence of obstructing officers, &c., representing the local authority, in carrying out the Act. The following section, which we select, deals with the subject generally:——

Sec. 306. “Any person who wilfully obstructs any member of the local authority, or any person duly employed in the execution of this Act, or who destroys, pulls down, injures, or defaces any board on which any bye-law, notice, or other matter is inscribed, shall, if the same was put up by authority of the Local Government Board or of the local authority, be liable for every such offence to a penalty not exceeding £5.

“Where the occupier of any premises prevents the owner thereof from obeying or carrying into effect any of the provisions of this Act, any justice, to whom application is made in this behalf, shall by order in writing require such occupier to permit the execution of any works required to be executed, provided that the same appear to such justice to be necessary for the purpose of obeying or carrying into effect the provisions of this Act; and if within 24 hours after the making of the order such occupier fails to comply therewith, he shall be liable to a penalty not exceeding £5 for every day during the continuance of such non-compliance.

“If the occupier of any premises, when requested by or on behalf of the local authority to state the name of the owner of the premises occupied by him, refuses or wilfully omits to disclose, or wilfully misstates the same, he shall (unless he shows cause to the satisfaction of the court for his refusal) be liable to a penalty not exceeding £5.”

=O′CHRES.= These are native earthy compounds of clay, coloured with oxide of iron, with frequently a little chalk, or magnesia. The differences in the colour arise partly from the quantity of iron present, and partly from the state of oxidation in which the iron is found. Several varieties are known in commerce——BROWN OCHRE, FRENCH O., OXFORD O., RED O., ROMAN O., YELLOW O. All these, with the exception of the first and fourth, have a yellow colour. ARMENIAN BOLE, INDIAN RED, VENETIAN R., and SPANISH BROWN, are also ochres.

All the ochres are darkened by calcination. The yellow ochres acquire a red or reddish-brown colour by this treatment. The pigment called ‘light red’ is thus prepared from yellow ochre.

=ODONTAL′GIA.= See TOOTHACHE.

=O′DORAMENTS.= _Syn._ ODORAMENTA, L. Substances employed in medicine on account of their odour. They differ from disinfectants, in only disguising, but not destroying, noxious vapours, &c. AMMONIA, STRONG VINEGAR, and PASTILLES, furnish the most familiar examples of this class of substances. See DISINFECTANTS, PERFUMES, &c.

=O′DOUR.= The emanation of an odoriferous or scent-giving body. See PERFUMES.

=ŒNAN′THIC ETHER.= See ETHER (Œnanthic).

=OFFIC′INAL.= _Syn._ OFFICINALIS, L. A term applied to substances or medicines ordered in the Pharmacopœia.

=OIL.= _Syn._ OLEUM, L.; HUILE, Fr. This name is given to numerous liquid or semi-liquid substances, expressed or drawn from animal or vegetable bodies; to various products of the distillation of bituminous minerals; and to several unctuous mixtures in perfumery and pharmacy. To facilitate reference, we have grouped the principal substances generally called ‘oils’ into classes, under the following heads:——OILS (Drying); OILS (Empyreumatic): OILS (Fixed); OILS (Medicated); OILS (Mineral); OILS (Mixed); OILS (Perfumed); OILS (Volatile). See these articles also _below_:——

=Oil, Consol′idated.= _Syn._ CAMPTICON, FACTITIOUS CAOUTCHOUC. A substance having most of the properties of india rubber, prepared by oxidising boiled linseed oil, or any other oil that hardens on exposure to the atmosphere. To obtain the solid oil, plates of glass are dipped into linseed oil, the films are then allowed to dry, and the process is repeated again and again until the plates are coated with many layers of perfectly oxidised oil. Instead of plates of glass, extensive surfaces of prepared cloth are employed when the manufacture is carried out on a large scale. The solid oil, having been scraped or peeled off the surfaces, is worked with a small proportion of shell-lac, by means of a mixing machine with hot rollers, until a material singularly like caoutchouc is produced. The consolidated oil can be rolled on to fabrics, so as to form a waterproof cloth, having the finish and flexibility of rubber-cloth. By the action of heat the consolidated oil may be converted into a hard substance resembling vulcanite and ebonite. Its useful applications appear to be very numerous, but its manufacture has not as yet made much progress.

=OIL-GAS.= A mixture of several gaseous hydrocarbons, obtained by passing common whale fat, resin, the heavy petroleum or shale oil, or the tarry residues left after the distillation of these two latter substances, or other cheap animal oil, through red-hot tubes, or by allowing it to fall in drops on red-hot stones or bricks arranged in an iron retort, or other suitable apparatus. The gas has great illuminating power, requires no purification, and is quite free from the ammoniacal and sulphur compounds which vitiate coal-gas. The sp. gr. of oil-gas varies with the heat employed in its production. It averages from 0·76 to 0·90, but it may rise as high as 1·1.

The composition of coal gas, as given by Payen, is as follows:——

+----------------------------+--------+-----------+
| | | Gas from |
| |Oil Gas.| Petroleum |
| | | residues. |
+----------------------------+--------+-----------|
| Olefiant gas and homologues| 22·5 | 17·4 |
| Marsh gas | 50·3 | 58·3 |
| Hydrogen | 7·7 | 24·3 |
| Carbonic oxide | 15·5 | —— |
| Nitrogen | 4·0 | —— |
+----------------------------+--------+-----------+

=OILS (Drying).= All the fixed oils have an attraction more or less powerful for oxygen, and, by exposure to the air, they either become hard and resinous, or they only thicken slightly, and become sour and rancid. Those which exhibit the first property in a marked degree, as the oils of linseed, poppy, rape, and walnut, are called ‘drying oils,’ and are used as vehicles for colours in painting. The others are frequently termed ‘glutinous’ or ‘non-drying oils.’

The resinifying or drying property of oils is greatly increased by boiling them, either alone or along with some litharge, sugar of lead, or white vitriol, when the product forms the ‘boiled oil’ or ‘drying oil’ (oleum desiccativum) of commerce. The efficacy of the process, according to Liebig, depends on the elimination of substances which impede the oxidation of the oil. The following formulæ are adopted for this purpose:——

1. Linseed oil, 1 gall.; powdered litharge, 3/4 lb.; simmer, with frequent stirring, until a pellicle begins to form; remove the scum, and when it has become cold and has settled decant the clear portion. Dark coloured; used by house-painters.

2. Linseed oil and water, of each 1 quart; white vitriol, in powder, 2 oz.; boil to dryness. Paler than the last.

3. Pale linseed or nut oil, 1 pint; litharge or dry sulphate of lead, in fine powder, 2 oz.; mix, agitate frequently for 10 days, then set the bottle in the sun or a warm place to settle, and decant the clear portion. Very pale.

4. Linseed oil, 100 galls.; calcined white vitriol (‘sulphate of zinc’), in fine powder, 7 lbs.; mix in a clean copper boiler, heat the whole to 285° Fahr., and keep it at that temperature, with constant stirring, for at least one hour; then allow it to cool, in 24 hours decant the clear portion, and in 3 or 4 weeks more rack it for use. Used for varnishes.

5. (Liebig.) Sugar of lead, 1 lb., is dissolved in rain water, 1/2 gall.; litharge, in fine powder, 1 lb., is then added, and the mixture is gently simmered until only a whitish sediment remains; levigated litharge, 1 lb., is next diffused through linseed oil, 2-1/2 galls., and the mixture is gradually added to the lead solution, previously diluted with an equal bulk of water; the whole is now stirred together for some hours, with heat, and is, lastly, left to clear itself by exposure in a warm place. The lead solution which subsides from the oil may be used again for the same purpose, by dissolving in it another lb. of litharge, as before.

6. (Wilks.) Into linseed oil, 236 galls., pour oil of vitriol, 6 or 7 lbs., and stir the two together for 3 hours; then add a mixture of fuller’s earth, 6 lbs., and hot lime, 14 lbs., and again stir for 3 hours; next put the whole into a copper, with an equal quantity of water, and boil for about 3 hours, lastly, withdraw the fire, and when the whole is cold, draw off the water, run the oil into any suitable vessel, and let it stand for a few weeks before using it. Patent.

7. (‘Allg. Polytech. Zeitung.’) Binoxide of manganese (in coarse powder, but not dusty), 1 part; nut or linseed oil, 10 parts; mix, and keep the whole gently heated and frequently stirred for 24 to 36 hours, or until the oil begins to turn reddish. Recommended for zinc paint, but is equally adapted for other purposes for which boiled oil is employed.

_Obs._ There is often a difficulty in obtaining the oils ‘bright’ after boiling or heating them with the lead solutions; the best way, on the small scale, is either to filter them through coarse woollen filtering paper, or to expose the bottle for some time to the sun or in a warm place. On the large scale, the finer oils of this kind are often filtered through Canton-flannel bags. The litharge and sulphate of lead used in the above processes may be again rendered available for the same purpose, by washing them in hot water, to remove adhering mucilage.

=OILS (Empyreumat′ic.)= _Syn._ OLEA EMPYREUMATICA, L. The ’empyreumatic oils’ of the old pharmaceutical writers were oily fluids obtained by the dry distillation of various substances, animal, vegetable, and mineral. But few of them are in use at the present day, though formulæ are given for them in some of the foreign pharmacopœias. Two or three have useful applications in the arts, and it is therefore necessary that we should briefly describe their preparation. When the ingredients are of a liquid or pasty nature, or become so when heated, they are usually mixed with about twice their weight of sand, powdered glass, or other like substance, to divide them, and thus expose them more effectually to the action of the fire. Care must also be taken to provide a well-cooled receiver, which must be furnished with a tube to carry off the non-condensable gases liberated at the same time as the oil. The products of the first distillation are generally purified by rectification, either alone or along with water. In general, they require to be preserved from the light and air.

The following are the principal substances belonging to this class:——

=Oil of Al′oes.= _Syn._ ALOETIC OIL; OLEUM ALOETICUM, L. 1. From Socotrine or hepatic aloes distilled along with sand.

2. (Batavian——Cadet de Gassincourt.) Olive oil, 1 lb.; hepatic aloes and myrrh, of each in powder, 2 oz.; olibanum, 1/2 oz.; distil in a sand bath, from a stoneware retort. Used as an external vermifuge for children; a portion is rubbed 2 or 3 times a day over the umbilical regions.

=Oil of Am′ber.= _Syn._ OLEUM SUCCINI, L. From coarse pieces of amber, distilled in an iron retort, either alone or reduced to powder and mixed with sand. The oil is separated from the fetid liquor and succinic acid which passes over, and rectified along with about 6 times its volume of water, by a gentle heat. It then forms ‘RECTIFIED OIL OF AMBER’ (OLEUM SUCCINI——Ph. L. 1836, O. S. RECTIFICATUM——Ph. D. 1826, O. S. PURISSIMUM——Ph. E. 1841). _Prod._ 20%.

_Prop., &c._ It has a pale yellow colour, a strong, ungrateful odour, and a hot, acrid taste; heat and air blacken and thicken it; it boils at 186° Fahr. Sp. gr. ·758 at 75° Fahr. It is antispasmodic, rubefacient, and stimulant.——_Dose_, 5 to 12 drops, made into an emulsion with mucilage; in hysteria, epilepsy, and convulsive affections. Externally, as a friction, either alone or combined with laudanum or sweet oil, in rheumatism, tic douloureux, hooping-cough, &c.

=Oil of Amber, Oxydated= (_Artificial Musk_). Pat into a cup 1 dr. of oil of amber, and add to it, drop by drop, 3-1/2 fl. dr. of strong nitric acid; let it stand for 36 hours, then separate and wash the resinous matter. Antispasmodic and nervine.——_Dose_, 5 to 10 gr. For children, 1/2 gr. to 1 gr.

=Oil, An′imal.= 1. (Empyreumatic or Fetid; OIL OF HARTSHORN, DIPPEL’S O.; OLEUM ANIMALE EMPYREUMATICUM, O. CORNU CERVI, O. DIPPELII, L.) Chiefly obtained as a secondary product in the manufacture of bone-black. Fetid and dark coloured. Used chiefly to make lampblack.

2. (Ethereal; RECTIFIED OIL OF HARTSHORN; OLEUM ANIMALE ÆSTHERIUM, O. CORNU CERVI RECTIFICATUM, LOCO OLEI ANIMALIS DIPPELII, L.)——_a._ A finer kind of animal oil, made by slowly distilling oil of hartshorn, and collecting only the first portion that comes over. Pale and limpid. Exposure to light discolours it.

_b._ (Ph. Bor.) Fetid animal oil distilled in a sand bath, and the product rectified with four times its volume of water. White, limpid, fragrant. Light discolours it.

_Prop._ The refined product is said to be antispasmodic, anodyne, and diaphoretic.——_Dose_, 5 to 30 drops, in water; in large doses it acts as an irritant poison.

=Oil of Birch.= _Syn._ OLEUM BETULÆ, L. From the inner bark of the birch, by heating it in an earthen pot with a hole in the bottom, to allow the oil to flow through into another jar sunk in the ground and luted to it. Thick, balsamic, fragrant. Used chiefly to dress russia leather.

=Oil of Box-wood.= _Syn._ OLEUM BUXI, O. B. EMPYREUMATICUM (Ph. L. 1746), L. From box-wood sawdust. Reputed resolvent; anodyne, antispasmodic, and diaphoretic.——_Dose_, 5 to 20 drops; in convulsions, epilepsy, gonorrhœa, &c. Externally, in toothache, &c.

=Oil of Bricks.= _Syn._ OLEUM LATERITIUM (Ph. L. 1746), L. From olive oil, mixed with brickdust, and distilled; or, from hot bricks steeped in olive oil, then broken to pieces, and distilled.

=Oil of Bricks (Factitious).= _Syn._ OLEUM LATERITIUM FACTITIUM, L. From linseed oil, 1 lb.; oil of turpentine, 1/2 lb.; oil of bones or of hartshorn and Barbadoes tar, of each 1 oz.; simply stirred well together. This is generally substituted for the preceding in the shops.

=Oil of Cade.= _Syn._ OLEUM CADINUM, L.; HUILE DE CADE, Fr. From the _Juniperus oxycedrus_ or Languedoc juniper. Used as oil of tar, which is commonly sold for it.

=Oil of Coal.= _Syn._ COAL OIL. From the gas-works. See NAPHTHA.

=Oil of Gua′iacum.= _Syn._ OLEUM GUAIACI, O. G. EMPYREUMATICUM, L. From guaiacum shavings or raspings. Reputed balsamic, pectoral, and resolvent.

=Oil of Harts′horn.= Bone oil and rectified bone oil are commonly sold for it, but are inferior to it. See OIL, ANIMAL (_above_).

=Oil, Paper.= _Syn._ RAG OIL, PYROTHONIDÆ; OLEUM CHARTÆ, L. On the small scale, by burning paper on a cold tin plate, and collecting the oil; on the large scale, by the destructive distillation of paper or linen rags. In baldness, toothache, ear-ache, &c.

=Oil, Par′affin.= See OILS, MINERAL.

=Oil, Petro′′leum.= See OILS, MINERAL, PETROLEUM.

=Oil, Rag.= See OIL, PAPER, _above_.

=Oil, Rock.= See NAPHTHA, OILS, MINERAL, PETROLEUM.

=Oil, Shale.= See OILS, MINERAL.

=Oil of Soot.= _Syn._ OLEUM FULIGINIS (Ph. L. 1746), L. From wood-soot. Fetid; reputed antispasmodic and nervine.

=Oil of Tar.= _Syn._ SPIRIT OF T.; OLEUM PINI, O. P. RUBRUM, O. TÆDÆ, O. PICIS LIQUIDÆ, L. By simple distillation from wood-tar. Reddish and strong scented. By one or more rectifications it becomes colourless and limpid. It soon gets thick. Used in ringworm and several other skin diseases, made into an ointment with lard. It is poisonous if swallowed in large doses.

=Oil of Tobac′co (Empyreumatic).= _Syn._ OLEUM TABACI EMPYREUMATICUM (Ph. U. S.), L. From tobacco, in coarse powder, gradually heated in a green-glass retort to dull redness, and kept at that temperature as long as any oil passes over; the oily portion is then separated from the water in the receiver, and kept for use. Highly narcotic and poisonous.

=Oil of Wax.= _Syn._ OLEUM CERÆ, L. From beeswax and sand distilled together; the product is rectified once or oftener. Reputed diuretic.——_Dose_, 3 to 6 drops.

=OILS (Fixed).= _Syn._ FAT OILS, UNCTUOUS O.; OLEA FIXA, O. EXPRESSA, L.; HUILES GRASSES, Fr. The fixed oils are compounds of carbon, hydrogen, and oxygen (oxyhydro-carbons), obtained from the organic kingdom, and characterised by their insipidity, unctuosity, insolubility in water, and being lighter than that fluid. Olive oil, which is obtained from the vegetable kingdom, and spermaceti oil, which is obtained from the animal kingdom, may be taken as types of the rest.

The fixed oils are chiefly found in the fruit and seeds of plants, and in thin membranous cells, forming what is called the adipose tissue, in the bodies of animals. According to their consistence, they may be classed into ‘OILS,’ ‘BUTTERS,’ and ‘TALLOWS,’

_Prop., &c._ Among the best-known properties of the fixed oils are——the permanent stain they give to paper, which they render translucid; their non-volatility at the ordinary temperature of the atmosphere, or at that of boiling water, or, indeed, at any temperature insufficient for their decomposition; their constantly floating on the surface of water when added to it; and, lastly, their inability to mix with that fluid. Some of them, as palm oil and cocoa-nut oil, are solid at ordinary temperatures; but the majority are fluid, unless they have been considerably cooled, when they separate into two portions——the one solid, consisting chiefly of stearin, or some analogous substance, and the other liquid, consisting chiefly of olein or elain. Nearly all of them, when exposed to the air, absorb oxygen rapidly, and either gradually harden or become rancid and nauseous. From the first are selected the ‘drying oil’ used by painters; the last are used as food, in cookery, and for machinery, lamps, &c. The whole of these oils, when heated to their boiling points (500° to 600° Fahr.), suffer decomposition, yielding various hydrocarbons; and when suddenly exposed to a red heat, they furnish a gaseous product (oil-gas), which was formerly employed for illumination. It is owing to this property of oil and liquid fats that candles and lamps give their light. The wick is a gas-producing apparatus in miniature. With the caustic alkalies and water the fixed oils unite to form soap. When some of these oils are absorbed by porous bodies, and thus expose a vastly increased surface to the air, they absorb oxygen with such rapidity as to generate a considerable degree of heat. Paper, tow, cotton, wool, straw, shavings, &c., slightly embued with oil, and left in a heap, freely exposed to the air or sun, often spontaneously inflame. In this way many extensive fires have arisen. The above is more particularly the case with linseed, rape, nut, and olive oil. The first, made into a paste with manganese, rapidly becomes hot, and ultimately inflames spontaneously.

The specific gravities of the fixed oils range between ·865 and ·970, water being 1·000.

_Prep._ The fixed oils, except where otherwise directed, are obtained from the bruised or ground fruit or seed, by means of powerful pressure, in screw or hydraulic presses, and are then either allowed to clarify themselves by subsidence or are filtered. Both methods are frequently applied to the same oil. In some cases the impurities are removed by ebullition with water, and subsequent separation of the pure oil. Heat is frequently employed to increase the liquidity of the oil, and thus lessen the difficulty of its expulsion from the mass. With this object the bruised mass, placed in bags, is commonly exposed to the heat of steam, and then pressed between heated plates of metal. This is always necessary with the ‘butyraceous oils.’

Another method is by boiling the bruised seed in water, and skimming off the oil as it rises to the surface. This is the plan adopted for castor oil in the West Indies.

In a few cases, for medicinal purposes, the bruised mass is mixed with 1/2 its weight, or an equal weight, of alcohol or ether, and after 24 hours’ digestion the whole is submitted to pressure, and the alcohol or ether removed by distillation at a gentle heat. The first menstruum is commonly employed for croton oil on the Continent; the second, for that of ergot of rye.

_Purif._ Several methods are adopted for refining or purifying the fixed oils, among which are the following:——

1. The oil is violently agitated along with 1-1/2 to 2% of concentrated sulphuric acid, when it assumes a greenish colour, and, after about a fortnight’s repose, deposits much colouring matter, becomes paler, and burns with greater brilliancy, particularly if well washed with steam or hot water, and clarified by subsequent repose or by filtration. This answers well for most of the recently expressed vegetable oils. It also greatly improves most of the fish oils.

2. A modification of the last method is to well mix the acid with the oil, then to blow steam through the mixture for some time, and afterwards to otherwise proceed as before.

3. FISH OIL (WHALE, SEAL, &c.) is purified by——

_a._ Violently agitating it with boiling water or steam, by placing it in a deep vessel with perforated bottom, through which high pressure steam is forced for some time; it is afterwards clarified by repose, and filtered through coarse charcoal.

_b._ The oil is violently agitated with a boiling hot and strong solution of oak bark, to remove albumen and gelatin, and next with high-pressure steam and hot water; it is, lastly, dried and filtered.

_c._ The oil, gently heated, is stirred for some time with about 1% of good chloride of lime, previously made into a milk by trituration with water; about 1-1/2% of oil of vitriol, diluted with 20 times its weight of water, is then added, and the agitation renewed and maintained for at least 2 hours; it is, lastly, well washed with steam or hot water.

_d._ Mr Davidson treats the oil first with a strong solution of tan, next with water and chloride of lime, then with dilute sulphuric acid, and lastly, with hot water.

_e._ Mr Dunn’s method, which is very effective, and admirable on account of its simplicity, is to heat the oil by steam to from 180° to 200° Fahr., and then to force a current of air of corresponding temperature through it, under a flue or chimney, until it is sufficiently bleached and deodorised; it is, lastly, either at once filtered or is previously washed with steam or hot water.

_f._ Another method, formerly very generally adopted and still in use, is to violently agitate the oil for some time with very strong brine, or with a mixed solution of blue vitriol and common salt, and then either to allow it to clarify by repose or to filter it through freshly burnt charcoal.

4. ALMOND, CASTOR, LINSEED, NUT, OLIVE, RAPE, and some other vegetable oils, are readily bleached by either of the following processes:——

_a._ Exposure in glass bottles to the sun’s rays, on the leads or roofs of houses, or in any other suitable position, open to the south-east and south. This is the method employed by druggists and oilmen to whiten their castor and linseed oils. 14 to 21 days’ exposure to the sun in clear weather during summer is usually sufficient for castor oil when contained in 2 to 4-quart pale green glass bottles (preferably the former), and covered with white gallipots inverted over them. The oil is filtered before exposing it to the light, as, if only in a slight degree opaque, it does not bleach well. Almond and olive oil are, when thus treated, apt to acquire a slight sulphurous smell; but this may be removed by filtration through a little animal charcoal, or, still better, by washing the oil with hot water.

_b._ Another method employed to decolour these oils is to heat them in a wooden, tinned, or well-glazed earthen vessel along with some dry ‘filtering powder’ (1 to 2 lbs. per gall.), with agitation for some time, and lastly, to filter them in the usual manner through an oil-bag. In this way the West-end perfumers prepare their ‘WHITE ALMOND OIL’ (OLEUM AMYGDALÆ ALBUM), and their ‘WHITE OLIVE OIL’ (OLEUM OLIVÆ ALBUM). Formerly, freshly burnt animal charcoal was used for this purpose, and is still so employed by some houses.

5. Mr Bancroft refines OILS FOR MACHINERY AND LUBRICATING PURPOSES generally, by agitating them with a lye of caustic soda of the sp. gr. 1·2. A sufficient quantity is known to have been added when, after repose, a portion begins to settle down clear at the bottom. About 4% to 8% is commonly required for lard oil and olive oil. After 24 hours’ repose the clear supernatant oil is decanted from the soapy sediment, and filtered.

6. Not only the oils above referred to, but all other oils and fats, may be rendered perfectly colourless by the use of a little chromic acid; or, what is the same, by a mixture of a solution of bichromate of potassa and sufficient sulphuric, hydrochloric, or nitric acid, to seize on all the alkali, and thus liberate the chromic acid.

7. PALM OIL and COCOA-NUT OIL are generally refined and bleached by either chromic acid or chlorine, or by heat:——

_a._ The ‘butyraceous oil’ is liquefied by heat in a wooden vessel, and 7% to 9% of good chloride of lime, previously made into a smooth cream with water, is added, and the whole assiduously stirred until the ingredients appear united; the mixture is then allowed to cool, and is next cut up into small lumps, which are exposed to a free current of air for 2, 3, or even 4 weeks; these are melted in a wooden vessel heated by high-pressure steam circulating through leaden pipes, or in a cast-iron boiler lined with lead, and an equal weight of oil of vitriol (diluted with about 20 times its weight of water) is poured in, and the whole gently boiled until the oil is discoloured and runs clear; the fire is then moderated, and the whole allowed to settle; lastly, the fire is removed, and the oil is left to cool very slowly.

_b._ The process with chromic acid has been already noticed, but is more fully explained _below_.

_c._ The oil, heated to the temperature of about 250° Fahr., is exposed to the action of high-pressure steam, which is continuously ‘blown’ through it for 10 or 12 hours, or even longer. The process is greatly facilitated by the introduction of some chromic acid.

8. Mr Watt’s methods of purifying fats and oils are very effective, more especially for those intended for illumination. They are as follows:——

_a._ (For FISH OILS.) Each ton is boiled for 1/2 an hour with caustic soda, 1/2 lb., previously made into a weak lye with water; or steam is blown through the mixture for a like period; oil of vitriol, 1/2 lb., diluted with 6 times its weight of water, is next added, the whole again boiled for 15 minutes, and allowed to settle for an hour or longer, when the clear oil is run off from the water and sediment into the bleaching tubs; here solution of bichromate of potash, 4 lbs., in oil of vitriol, 2 lbs., previously diluted with water, q. s., together with a little nitric acid and some oxalic acid, are added, and after thorough admixture of the whole, by blowing steam through it, strong nitric acid, 1 lb., diluted with water, 1 quart, is poured in, and the boiling continued for 1/2 an hour longer; a small quantity of naphtha or rectified spirit of turpentine is then mixed in, and the oil is, finally, well washed with hot water, and left to settle.

_b._ (For PALM OIL.) The oil is melted by the heat of steam, and, after it has settled and cooled down to about 130° Fahr., is carefully decanted from the water and sediment into the steaming tubs; here a mixture of a saturated solution of bichromate of potash, 25 lbs., and oil of vitriol, 8 or 9 lbs., is added, and after thorough admixture, hydrochloric acid, 50 lbs., is poured in; the whole is then constantly stirred until it acquires a uniform greenish colour, or is sufficiently decoloured, a little more of the bleaching materials being added if the latter is not the case, after which it is allowed to repose for half an hour to settle; it is next run into a wooden vat, where it is washed, &c., as before.

_c._ (For VEGETABLE OILS.) These are treated with a solution of chromic acid, or with a solution of bichromate of potassa, or some mineral acid, as noticed at No. 6. For COLZA, LINSEED, MUSTARD, NUT, and RAPE OIL, a little hydrochloric acid is added; but for ALMOND, CASTOR, OLIVE OIL, and POPPY OIL, no such addition (at least in excess) is required.

9. RANCID OILS and FATS are recovered by boiling them for about 15 minutes with a little water and calcined magnesia; or, by filtering them through freshly burnt charcoal.

In reference to the above processes, it may be useful to remark, that chlorine, the common bleacher and deodoriser of other substances, cannot be well employed directly in the purification of oils, as certain chemical reactions occur when these substances are brought together, which increase the colour instead of removing it, and are often otherwise injurious. The same remarks apply to the use of the ‘chlorides,’ which frequently fails in unskilful hands, and is, indeed, of questionable utility, except, perhaps, in the case of palm oil. Even charcoal exerts little of its usual energy on the oils, and whilst it removes or lessens their offensive odour, sometimes increases their colour. The addition of 1% or 2% of very pure and recently rectified naphtha or oil of turpentine (camphine) to lamp oil is a real improvement, since it increases its combustibility and its illuminative power.

OILS FOR MEDICAL PURPOSES, as CASTOR OIL, COD-LIVER OIL &c., must not be subjected to any process beyond mere clarification by subsidence, filtration through Canton flannel or porous paper, or, at the utmost, washing with warm water, as otherwise their active and valuable properties, if not wholly removed, will be considerably lessened. See FILTRATION.

_Purity._ The fixed oils vary greatly in their value, and hence the constant inducement which leads the unprincipled dealer to adulterate the more expensive ones with those of a similar character, but of an inferior kind of grade. Various methods are adopted to detect these frauds, among which the following are the most valuable of those capable of general application. Others referring to individual oils will be found under the respective heads.

1. (From the odour.) The method of applying this test is to heat a few drops of the oil under examination in a small porcelain, platinum, or silver spoon or capsule (a watch-glass answers well), and to carefully compare the odour evolved with that arising from a known pure sample of the same kind and quality of the oil similarly treated. The odour of the two, when each is pure, is precisely alike, and immediately suggests the plant or animal from which it has been obtained. The presence of LINSEED, NUT, RAPE, SEAL, TRAIN, or WHALE OIL, is thus readily detected, and the imperfections of the sample, even if pure, rendered much more perceptible.

2. (From the density.)——_a._ According to M. Penot, every oil supposed to come from the same plant, or the same animal, has its own particular density, which, at the same temperature, never deviates more than a few thousandths. To apply this test, the relative density or specific gravity of the sample must be determined. This may be done by means of a thousand-grain bottle or an ordinary ‘AREOMETER,’ or, more conveniently, by an ‘ELAÏOMETER’ or ‘OLEOMETER,’ constructed and graduated for the purpose. ‘Fischer’s ELAÏOMETER’ or ‘OIL-BALANCE’ is much employed on the Continent for this purpose, and is a very useful instrument. On the large scale, the weight of an accurately measured imperial gallon of the oil may be taken.

_b._ M. Lauret, an eminent Parisian chemist, a short time since observed that the variations of the density of an oil from adulteration are rendered much more apparent when it is examined in a heated state. To render this discovery practically available, he plunges an ‘elaïometer,’ graduated for the given temperature, into a small tin cylinder nearly filled with the oil, and then places this in a vessel containing boiling water; as soon as the whole has acquired a uniform temperature, he observes the point on the scale of the instrument at which it floats. This point for——

Colza oil is 0°
Fish oil 83°
Poppy oil 124°
Hemp-seed oil 136°
Linseed oil 210°

_c._ By employing a specific gravity bottle or small glass globe, fitted with a stopper in which is hermetically fixed a capillary tube of about 8 or 9 inches in length, we may apply the above principle of M. Lauret with the greatest accuracy. This little apparatus is filled with the oil, and then immersed in boiling water for a sufficient length of time for it to acquire that temperature; it is then removed and weighed. The smallest adulteration is, it is said, in this way immediately detected.

When the density of the given sample has been taken, and the name of the oil used to adulterate it is known, the quantity of the latter present may be approximately determined from the specific gravities by the common method of alligation.[49]

[Footnote 49: See MIXTURES, Arithmetic of.]

3. (Sulphuric-acid test.)——_a._ Heidenreich was the first person who gave a useful and general application to the reactions which occur when oil of vitriol is mixed with the fatty oils. As soon as these substances are placed together, very intense chemical action commences, the temperature of the mixture rises, and the mass becomes coloured. These changes are sufficiently varied in the case of the different oils to furnish us with the means of identifying many of them, and of determining their purity. The method of M. Heidenreich is to lay a plate of white glass over a sheet of white paper; on the glass he places 10 or 15 drops of oil, and then adds to it a small drop of concentrated sulphuric acid (‘oil of vitriol’). The appearances which follow differ with the character of the fatty oil examined, and whether the acid is allowed to act on the oil undisturbed (without stirring) or the two are stirred together with a glass rod. In many cases, as with tallow oil, a peculiar odour as well as a change of colour is developed, and a further means of detection supplied. M. Heidenreich has minutely described these reactions, which, for the most part, closely resemble those given in the table, p. 1129. It is necessary, however, in order to ensure great accuracy, to compare the effect of the reagent on the sample with those which it produces on pure oil of the same kind and character under precisely similar circumstances.

_b._ M. Penot, who has followed up the researches of M. Heidenreich with considerable success, recommends the employment of 20 drops of oil, instead of only 10 or 15; and the use of a small capsule of white porcelain, instead of a plate of glass. He also employs a saturated solution of bichromate of potash in sulphuric acid, which he uses in the same proportion as before; but in this case the oil and the reagent are always stirred together.

The observations of M. Penot have been repeated in many cases by Mr Cooley, and the results, with additions, and rearranged, are given in the table, p. 1129.

“By perusing this table,” writes M. Penot, “it will be observed that the same oil does not, under all circumstances, yield precisely similar results with the same reagent. This depends on the place of growth, the age, and the manner of pressing. If, however, any oil be examined comparatively with a perfectly pure one, the proof of adulteration may be rendered, if not certain, at least probable, by noting the difference. Thus I obtained, by adding 1 part of either whale-train, or linseed oil, or oleic acid, or 10 parts of rapeseed oil, the following results:——