position corresponding to that of the line N Q, in like manner be sheered across the river. On broad rivers, and when objects of great bulk and weight, as horses, carriages, or artillery, are to be conveyed across, two boats or barges placed in parallel positions, and carrying a platform extending between their exterior gunwales, are employed: the bay or interval between the vessels is as wide as is consistent with the strength of the platform, in order that as much as possible of the current may act against a side of the lower vessel. The vessels are made narrow and deep, and each is provided with a mast, which may be from twenty to thirty feet in height; these are connected together at ten or fifteen feet from the platform by two horizontal beams, one above the other, and between them is a block of wood which is capable of sliding from one mast to the other. The cable or chain is made to pass through a perforation in the sliding piece, and the latter is placed contiguously to either mast, according to the direction in which the vessels are to move. A drawbridge is constructed on each side of the platform, and one of them is let down to form a passage when the vessels arrive at the landing place on either side of the river. Each vessel has a rudder, and the tillers are connected by a bar, in order that one man may be able to turn both. For ample details concerning the subject of this article, see Sir Howard Douglas on 'Military Bridges.' FLYING SAP, is the sap formed by placing and filling several gabions at the same time, and not in succession as in the usual method employed in making the second parallel in the attack of a fortress. FO, pronounced by the Chinese Fuh, is the name by which Buddha is worshipped in China. According to the Chinese authorities quoted in Dr. Morrison's Chinese Dictionary' (vol. i. part i. pp. 92, 93), the religion of Fo was introduced into China in the seventh year of the reign of the Emperor Ming, about A.D. 50. Though the Chinese government has usually discountenanced, and at some periods persecuted, the followers of Fo, they have always been very numerous; yet Sir J. F. Davis remarks, in his work on the Chinese (vol. ii. p. 94), that, "the present condition in China of the religion of Fŏ is very far from flourishing; and the extensive and magnificent establishments which have been founded in former times are evidently in a state of dilapidation and decay. It is rarely that one meets with any of their nine or seven-storied pagodas in tolerable repair, though one or two of these striking and elegant objects occur in almost every landscape. Between Macao and Canton there are no less than four or five ninestoried pagodas on elevated points by the river-side, and every one of them is in a state of ruin." [BUDDHA.] FOCUS, Geometry. [ELLIPSE; HYPERBOLA; PARABOLA.] FOCUS, a Latin word signifying a hearth or fire-place, used in optics to denote the point at or near which the rays of light are collected by a lens or mirror. Its distance from the lens or mirror is called the focal length. [LENS; MIRROR.] FOG. [MIST.] FOG SIGNALS. The blowing of a horn, the ringing of a bell, the beating of a drum or gong or empty cask, the firing of a gun,-in short, any uncouth noise made on board a ship to warn others of her presence, is in a fog a means of safety. The Admiralty have rules for the government of a fleet of men of war in thick weather, such as occasional firing or ringing of a bell to indicate what tack a ship is upon, &c.; but little has been done for single ships of the merchant service on this important subject beyond certain regulations for the use of light-houses and light vessels, although every provision was made in the Merchant Shipping Act of 1854, for the enforcing of such regulations as might issue from authority. Difficulties evidently beset the question, as the safe passage of a ship in foggy weather through our crowded maritime highways must depend so much on individual precaution. As the principal commerce of the kingdom is becoming more and more carried on by steamers, and their "whistles" are a powerful and characteristic mode of warning, it might be well to organise a few signals for general use, after the following manner. Let the mark "- represent, on paper, a sound from the steam whistle, lasting while a person could leisurely count four, and the mark" indicate another sound from the whistle, enduring while a person could leisurely count two. It being in a fog so important to know in what direction a steamer is coming or proceeding, the following eight signals would form a complete code, which might moreover, from their extreme simplicity, be used either in a dark night or in hazy weather at any time. If a vessel is standing towards the North,} let her course be represented If North-East If North-West If East If South " If South-East If South-West If West As every sailing-vessel is supposed to carry a "fog horn," the above signals so easily made on it, or on a bugle, or with a common whistle, or even with the mouth (on an emergency), would in many cases pro bably prevent collision [COLLISIONS AT SEA]. And further, if a vessel be on the starboard tack, close hauled, a prolonged blow would announce it, and if close hauled on the port tack, a few short repeated sounds of any sort would give sufficient notice: while a vessel at anchor might make any beating sound. But all precautions taken on board ship in certain cases will prove useless unless means be taken to give sounds from the shore. The humane but partial and voluntary custom in some parts, of ringing a village church bell on a coast in thick weather, if rendered compulsory, -or the sounding of a bell at certain conveniently situated coastguard stations along the shore,-would not only alleviate the dangers which at present threaten seamen, but it would be a boon to boatmen and fishermen. For instance, three long sounds of equal length might always be used to indicate the shore. An excellent fog-horn has recently been introduced from the United States. Fog-signals, made with an explosive material, are also used on railroads. They are placed on the rail; the engine-wheel on passing over it causes it to explode with a noise calculated to announce the approach of the train to a considerable distance. FOIL, is a very thin sheet of metal, made usually for placing beneath artificial gems to heighten their brilliancy. Foils are made of tin, copper, tinned copper, or silvered copper-the last for the best work. They are left white for imitative diamonds, but are coloured for imitative rubies, sapphires, &c. The best white foil is made by coating a plate of copper with a layer of silver, and then rolling it into sheets in the flatting mill. The coloured foils are prepared by coating the white foil with coloured varnish. The principal colours used by artists are employed, mixed with mastic, spirit, and drying oil, to form the coloured varnishes. The following are examples :-amethyst foil, lake and Prussian blue finely ground in drying oil; sapphire foil, Prussian blue and drying oil; garnet foil, dragon's blood and rectified spirit; emerald foil, pale shellac, alcohol, and acetate of copper; ruby foil, lake, isinglass, and shellac; topaz foil, turmeric, annatto, and shellac. Sheet lead, so extremely thin as to resemble foil, is employed as a lining for tea-chests. Mr. Wimshurst, one of the managers of the Assam Tea Company, invented, in 1858, a very peculiar method of producing this foil. It is said that England sells no less than 4000 tons of lead annually to the Chinese, chiefly to be made up into foil for lining their tea-chests; this they do rather clumsily. The Assam Company paid from 2000l. to 3000l. a year for lead-foil made on the old method of rolling; but Mr. Wimshurst has effected a great saving in this item by the adoption of his new method. He makes a cylinder of lead, by casting in a mould having a mandril or core in the centre; the mould opens by a hinge into two halves, and liberates the metal. A knife or cutter, as long as the cylinder, is gradually brought up to it, and shaves the surface. The cylinder rotates slowly while being thus cut. The mechanical arrangement is such that the cutting-blade advauces gradually towards the axis of the cylinder, and the rate of this advance determines the thickness of the film. The film is received on a collecting spindle, which can be removed with the coil upon it. The cutting-machine acts equally well on a cylinder of tin or one of lead, or of a combination of the two metals. FOLK-MOTE, or FOLK-GEMOTE, literally a meeting of the people; an assembly under the Anglo-Saxon government, respecting the nature of which some of our antiquaries have differed. Sir F. Palgrave believes that it existed in Britain before the establishment of the Saxons. Somner, in his 'Anglo-Saxon Dictionary,' calls it a general assembly of the people for considering and ordering matters of the Commonwealth. So the laws of King Edward the Confessor, "Folcmote, i. e., vocatio et congregatio populorum et gentium omnium, quia ibi omnes convenire debent, et universi qui sub protectione et pace Domini Regis degunt." The continuation of this statute of Edward the Confessor expressly directs that the meeting of the Folcmote should be held once in the year upon the 1st of May. est enim quod ibi debent populi omnes, &c., semel in anno scilicet convenire, scilicet in capite Kal. Maii." (Wilk., 'Leg. Anglo-Sax.,' p. 204.) "Statutum Brady, in his 'Introduction to Old English History,' Gloss. p. 47, is entirely mistaken when he speaks of it as an inferior ordinary court, held once a month. This was the Hundred Court. The Folk-mote and Shire-mote (or general meeting of a county) were synonymous. (Wilk. ut supr. Gloss. p. 404.) According to Sir F. Palgrave, the Folk-mote was a representative assembly to which the various districts sent their sheriff (gerefa) and four men. It certainly possessed judicial powers, of which he gives examples ('Rise and Progress of the English Commonwealth'); and jurors appear in many instances to have been selected from among the representatives attending the Folkmote. The Folk-mote, indeed, appears to have had nearly the same constitution, with powers, limited by the locality it represented, as the Witenagemote; to which frequently the same representatives were sent as attended the Folk-mote. In later times a Folk-mote, according to Stow, among the citizens of London, meant a meeting of themselves. Fabyan, in his Chronicles' (edit. 1811, p. 344), mentions a court of folk-mote held at Paul's Cross in 1256; and another assembled by command of Henry III. (ibid. p. 345), "where the king, according to the former ordinances made, axed licence of the commonalty of the city to pass the sea." FOMENTATIONS are liquid applications, generally of a warm temperature, placed in contact with a limited portion of the body, to mitigate or remove disease of the part, or of the neighbouring organs. They differ from partial or local baths, chiefly in the greater length of time which they are kept applied. Flannel cloths, or other substances, such as the spongio-piline, fit to retain heat and moisture, are commonly employed. To enable these substances to retain the heat still longer, they are often covered externally with oiled silk. It is proper to renew the application before the cloths begin to give a feeling of coldness. The liquids used are of various kinds, sometimes pure water; at other times medicated; they are termed emollient when charged with mucilaginous principles, such as mallows, and sedative or anodyne when they contain a narcotic principle, such as poppy heads. FONT, the vessel placed in a church to contain the water employed n baptism. The form of the font is evidently derived from that of the larger Roman stone vases, but few if any of the fonts now found in churches are of a date earlier than what in architecture is known as the Romanesque period. In our own country there are a great many fonts, curious both for their antiquity and their architectural design. One or two are, on questionable grounds, attributed to the Saxon period; but those respecting which there is no difference of opinion range from the Norman period to the decline of Gothic architecture. What may be called the normal form of a font is that of a cup or bowl hollowed out for water, and supported on a thick solid stem. The exterior of the bowl is in the older examples round, or square, but in the later most commonly octagonal; and the sides and stem are often highly enriched with sculptured figures, and occasionally traces of colour and gilding still remain, as at Gorleston and Blythborough, Suffolk, and Gresham, Norfolk. In many instances, a flight of steps forms a base for the stem; and in fonts of the Perpendicular period, even the steps are carved with panels, having quatrefoils and rosettes Funk within them. From about the middle of the 13th century, when by a rescript of the Archbishop of Canterbury fonts were required to be covered and locked, the lids of fonts began to acquire an ornamental character equally with the fonts themselves. At first they were merely plain covers with padlocks, but eventually (though probably not before the middle of the 15th century) they assumed a pyramidal or spirelike form, richly carved with a profusion of shafts, buttresses, and tracery, piled up to the apex. Covers of this kind still remain at Castleacre and North Walsingham churches, Norfolk; Ewelme, Oxfordshire; Thaxted, Essex, and elsewhere. The more ancient fonts are generally very large; the basin being sufficiently capacious to permit of the baptism of the infant by immersion. As a rule they are made of stone, and almost always from a single block; but some leaden fonts of Norman, as well as of later date, are still extant both in this country and in France: in the latter country a few remain of copper or bronze. Fonts were mostly placed in the western end of the nave, near the entrance of the church; but sometimes in a portion of the church separated from the body of the building by walls or a screen, or entirely detached from it. Of these baptisteries as they were called [BAPTISTERY], examples occur at Canterbury Cathedral; Luton, Bedfordshire; Cranbrook, Kent; and Menacuddle, St. Austel, Cornwall; but more perfect examples may be found in some recent churches erected in conformity with strict "ecclesiological" principles; as All Saints, Margaret-street, London, where the font (which has a carved cover of the kind described above), is enclosed in a rich baptistery, which is shut off from the nave by low walls, though under the same roof; and at All Souls' church, Halifax, where a baptistery is formed in the basement of the tower, which stands at the north-west angle of the church. Fonts of Norman date are nearly always large and massive; the basin is usually round or square, but some occur which have been rendered octagonal by chamfering off the angles of the square blocks, as at Drayton church, Norfolk. They are supported on a very thick stem, but in some of the largest there are also smaller shafts placed under the angles of the basin, as at Lincoln cathedral; Ifley church, Oxfordshire; South church, Hayling Island, Hampshire, &c. Norman fonts are frequently sculptured with rude bassi-relievi, of the Crucifixion or Baptism of Christ, or some other typical subject, figures of the apostles, saints, grotesque figures, scroll-work, &c. Porchester church, Hants, has a very ancient circular font, resembling in character the puteal, or circular stone-mouth of the well in the atrium of a Roman house it is decorated with intersecting arches on columns, with a frieze of foliage and figures above. At Coleshill, Warwickshire, is a Norman font, of which the basin is a mere cylinder, but elaborately sculptured outside with the Crucifixion (enclosed within a circle), the evangelists, &c., and supported on an enormously thick stem. A handsome circular font richly covered with scroll-work occurs at Great Shefford church, Berks; at Monks Risborough, Buckinghamshire, the circular basin is fluted. Most Norman fonts are of stone, but some occur of lead. One of the most remarkable of these is in Dorchester church, Oxon. The bowl is of cast lead, of 1 foot 10 inches internal diameter, 2 feet 2 inches external, and 1 foot deep. Around the outside are eleven seated figures under semicircular arches, representing, probably, the Apostles-Judas being omitted. The pedestal is of stone and more modern. A leaden font of very beautiful workmanship is in the chapel of Llancourt, on the Wye. Fonts of the same date in Normandy, are almost exactly similar in style, but somewhat richer and more refined in finish; showing, not merely similarity of origin, but supporting the probability of their being executed by the same workmen, or workmen trained in the same school. Fonts of the First Pointed, or Early English date, are like those of the preceding period, circular and square, but they are likewise not seldom octagonal. In general character they greatly resemble the Norman, but they differ from them in being somewhat less massive, and more finished in style; they have sometimes arcaded-work, sometimes trefoils on the bowls, with slender shafts dividing the panels, and almost always detached supporting shafting, as well as a thick central stem. In the Second Pointed, or Decorated Style, the fonts are finer in design than the earlier examples, but less refined in execution than might be expected from the superiority of the buildings of this period. The basins are now usually octagonal, but occasionally they are hexagonal, as at Rolvenden, Kent, and Drayton Parsloe, Buckinghamshire. Fonts of this period are characterised by the flowing tracery of the panels, engaged shafts, highly enriched ornamentation, diapered panels, and occasionally elegant sculpture. A good example of this style occurs in the church of All Saints, Norwich. In the Perpendicular, or Third Pointed Style, the form is almost invariably octagonal. Occasionally figures of men or animals are introduced as apparent supporters to the bowl, as at St. Martin's, Oxford, where supporting figures are placed within recesses formed by buttresses at the angles of the stem; and at St. John's, Norwich, where lions are similarly placed. The ornamentation is now much more rich, becoming more and more florid in the later examples, and at last erring greatly on the side of excess of decoration, as in the otherwise fine font at Walsoken, Norfolk. On the panels of the basin foliated circles or quatrefoils frequently inclose roses or heraldic shields. The stem, where single, is often octagonal and panelled. Statuettes and bassirelievi, sometimes very beautifully executed, occur in the costlier examples, both within niches on the panels of the basin, and around the stem. A very beautiful example of a Perpendicular font of the best period occurs at East Dereham Church, Norfolk, of which we give an engraving. The lofty pyramidal font-covers spoken of above, XXX Font in East Dereham Church, Norfolk, from an original drawing made by Mr. W. B. Clarke, architect, in 1834. are chiefly of this period-the famous one at Ewelme, Oxford, which is 10 feet 6 inches high, is a characteristic example. From the decline of Gothic architecture little attention was given to fonts in this country; and not only were no new ones of any artistic pretension executed, but the old ones were neglected, and often applied to the most unworthy uses. Since the revival of Gothic architecture, however, many fonts have been executed of a very costly kind, and exhibiting great imitative skill, if not much originality of design. Simpson's 'Series of Baptismal Fonts,' and Paley's 'Illustrations of Baptismal Fonts,' furnish descriptions and engravings of numerous English fonts of the several periods, and the latter work gives also careful admeasurements of each example: the Archæologia,' the 'Archæological Journals,' and the local histories, will supply many additional instances. Sufficient examples and descriptions (for the purpose of comparison) of French fonts, will probably be found in M. A. De Caumont's Cours d'Antiquités Monumental,' vol. vi., and 'Atlas,' Paris, 1841; and his 'Rudiment d'Archéologie-Architecture religieuse,' Par. 1854. FOOD. All organised bodies are nourished by he introduction into their internal structures of materials from without. Such materials are called indifferently aliments or food, and are fitted to supply and maintain the fluid and solid matter of the body. For this purpose they must either be soluble naturally, out of the body in common menstrua such as water, or capable of being dissolved by the digestive principle of the stomach. However diversified the articles employed may be in external appearance or chemical composition, they are reduced by the action of the organs of digestion into a fluid (chyle) [DIGESTION, in NAT. HIST. DIV.] of homogeneous character, which is reconverted into solids and fluids of different natures by the influence of the powers of assimilation. Before undergoing this second change, they must be brought into the state of arterial blood, and so form a part of the circulating fluids of the body. Substances which are incapable of undergoing these successive changes cannot be considered as articles of food, or capable of imparting nourishment to the frame. There are however various articles which, although incapable by themselves of nourishing, appear, when taken in conjunction with other articles, to contribute essentially to nutrition. But even of a substance unquestionably nutritious, the whole mass is never completely nutritive, that is, capable of being entirely assimilated; some portion of it merely giving it bulk, or being of a nature calculated to make certain impressions on the organs of digestion, and to stimulate them to those actions which conduce to the exercise of the function of digestion, such as the tannin of our vegetable food, salt and other condiments. Those substances which have previously been endowed with life can alone be considered as affording nutriment to animals of a high degree of organisation, such as man, of whose aliment we here mean to treat. For a practical view of the subject, it may be divided into two heads, namely, the substantials and the accessories; the first comprising the real materials or sources of nourishment; the second, condiments, &c., which either render the food more grateful to the palate, or by a vital or chemical action on the organs of taste and the stomach, promote its digestion. It is customary to distinguish the articles of food into solid and fluid, or meats and drinks, and into animal and vegetable. But the former is merely a distinction of convenience, and does not extend to any ultimate difference in the nature of the material, but only to the manner in which they are respectively treated by the organs of digestion; while the latter is only important in a medical point of view, as relates to the amount of nutriment in a given quantity of food, and the impression which the two kinds of food make upon the system generally. "Specific differences are distinguishable in the chyme at least, if not in the chyle, according as the food from which it is formed has consisted of vegetable or animal matter, and according as it has contained fatty or oily substances, or been destitute of them." Nevertheless as those substances alone contribute to the nourishment of the body by being assimilated by it which can be resolved into their organic molecules, and as these are only found in the proximate principles of animals and vegetables, of which principles none perhaps are exclusively animal, it seems most advantageous to treat at the outset of the principles, without reference to the source whence derived. The molecules can only be liberated by being diffused through some fluid, and therefore it matters not whether they be brought into such a condition by external agency or by the apparatus with which the higher animals are furnished, namely, the teeth, stomach, &c. To a fluid state they must be brought before they can pass the fine strainers of the alimentary canal. The resolution of the materials of food into their organic molecules is the real office of the digestive organs, while exercising that function within healthy limits; the resolution of the proximate principles into their elementary or ultimate principles, when various gases are evolved, is a morbid or diseased action of these organs. The proximate principles of alimentary substances consist sometimes of three, sometimes of four elementary or constituent principles. Those which consist of three are of most frequent occurrence in the vegetable kingdom; those which consist of four are of most frequent occurrence in the animal kingdom. Where the elements are three only they are generally oxygen, hydrogen, and carbon; where four, oxygen, hydrogen, carbon, and nitrogen, or azote. dominance of carbon is the characteristic of vegetable matter; the predominance of nitrogen the characteristic of animal matter. Wherever nitrogen is absent in animal matters the substance approximates, or is analogous to, vegetable matter, such as animal fats, which closely The pre resemble vegetable oils. Animals which are decidedly carnivorous do not prosper if kept long on food destitute of azote; but man, whose dwelling-place is under different climates, can dispense with an azotised diet better in some parts of the world than in others, for instance, better in tropical countries than near the poles. The pilgrims and attendants on the caravans in their journeys across the deserts of Africa can subsist for a length of time on gum, which does not contain azote. Majendie, who carefully investigated the subject, concludes from his experiments-1st, That animals derive the azote which enters into their composition entirely from their food, and hence, that no animal can live for a considerable time on food entirely destitute of azote. 2nd, That animals, even those naturally carnivorous, can live a certain time upon food entirely destitute of azote, in consequence of which the excretions of those naturally carnivorous become altered, throwing off less azote than when they are fed on animal food, and acquiring the properties which these excretions have in animals whose food contains a very small proportion of azote. 3rd, That vegetable and animal substances destitute of azote are highly nutritious, provided at the same time azote can be supplied from some other aliment containing it, though in small proportion. It seems however that vegetable aliments acquire an accession of azote in the digestive organs, though probably at the expense of some part of the system. Admitting the general correctness of Majendie's views, alimentary substances may be divided into three classes: I. Those which contain azote, carbon, oxygen, and hydrogen. The first class naturally demands the greatest share of attention, because "the aliments which contain azote correspond with animal substances in general, and are calculated to repair the waste of our solids and fluids without great alteration or effort in the digesting organs. All the immediate principles of this class are not however equally digestible, or possessed of the same properties." It is necessary therefore to say a few words on the leading forms or states in which azotised principles occur. Fibrin: this and other terms are retained here, though not in strict accordance with the present chemical phraseology with respect to food and its constituents, because these having been long in use are better known to unscientific readers. The modern views and phrases are all given under the Art. FOOD, in NAT. HIST. DIV. Animal fibrine, animal albumen, and animal caseine, constitute the chief animal proteinaceous principles, that is, compounds of protein and sulphur, and in the two former of phosphorus also. [PROTEIN.] 1. Fibrin.-This is found in greatest abundance in the animal kingdom, constituting the principal part of the muscular fibre of animals, and no inconsiderable portion of the blood, when by rest that fluid is coagulated. It has been thought to exist in some of the constituents of the vegetable kingdom, particularly in the juice of the fruit of the Carica Papaya, or papaw-tree, and in certain other plants with a milky juice, such as the Palo de Vaca, Cow-tree (Galactodendron utile) of South America, and some fungi, or mushrooms. The identity of the principle found in these vegetables with animal fibrin has been questioned by some recent chemists. Dr. Thomson considers the principle of the cow-tree distinct, and terms it galactin, while Gmelin terms that of the others emulsin, which he considers analogous to gluten. Fibrin constitutes the chief part of the solid matter of the muscles of animals, particularly of those which are old and have dark-coloured dry flesh it is that portion which remains in the form of fibres after all the soluble matters have been removed from the flesh of animals by long boiling. It is insoluble in cold water, is corrugated by long boiling in water, is insoluble in alcohol, but strong acetic acid causes it to swell considerably, rendering it transparent like cartilage, in which state it may be dissolved, or, at least, diffused through water by long boiling. The flesh of animals is divided into white and coloured, and indeed it differs in the same animal at different ages, having different accompanying constituent principles at different periods of life. Thus in the calf the muscles are white, or only pinkish; in the ox they are deep red; in the first state much gelatin and little of ozmazome is present; hence the gravy of veal easily gelatinises, while that of beef rarely does so. Fibrin is in general more tender, that is, more easily digested, because the force of aggregation is more easily overcome by the powers of the stomach in middle-aged than in old animals, and in the flesh of the female than that of the male, unless the males have been castrated when young. Albumen is another important constituent of animal bodies, but of more sparing occurrence in vegetable substances. In animal substances it occurs in two states, fluid and coagulated. The most perfect examples of it in the former state are the white of eggs, which is an alkaline solution of albumen, and the blood, which is likewise probably an alkaline solution of albumen. Coagulated albumen constitutes cartilage, horn, hair, and the nails or hoofs of animals. It forms the chief constituent part of oysters, muscles, snails, &c. Milk is an albuminous fluid. At the temperature of 165° Fahr. albumen is coagulated, and it is likewise solidified by many acids, such as that of the gastric juice (in the form of rennet), and by some metallic salts. Milk, though coagulated by acids, is not so by boiling. Albumen is likewise found in the green feculæ of plants in general, and in some vegetables in very considerable quantity, such as the fruit of the Hibiscus esculentus, or Ochro, and the bark of the Ulmus campestris, or elm. The former is used in Sicily to thicken soups, and both are used in the West Indies to clarify sugar. Animal caseine, the portion of milk which is coagulated by rennet, and some acids out of the body, and by the gastric juice in the stomach, constitutes curd. In the milk it is kept in a fluid state by the alkaline principles present. These are neutralised by the acids. Gelatin abounds in most animal substances, and is common in proportion to the youth of the individual. It exists in bones, ligaments, tendons, membranes, skin, muscles, as well as in a portion of the horns of animals. The skin of fish, much of their substance, and the swimming-bladder of the sturgeon, are formed of gelatin. It is remarkably bland and nearly insipid, as may be remarked in any solution of isinglass. Gelatin is not of common occurrence in the vegetable kingdom, and it is distinct from vegetable jelly. It occurs, however, in the Protococcus nivalis. Gelatin is the opposite of albumen in its qualities; in cold water it swells, is not transparent, is soft, and somewhat elastic. The gelatin of isinglass and of young animals is slowly but completely soluble in scarcely tepid water, while that of old animals, of skins, and of hoofs or feet, requires warm water for its solution. The solution, when of a certain strength, gelatinises into a tremulous or solid jelly. It is a highly nutritious principle, but its digestibility is, in popular estimation, much overrated. Mucus is a principle probably found only in animal structures, unless it exists in some plants of the tribe of Boraginacea. It differs from albumen principally in not being coagulable by heat, while it differs from gelatin in not being precipitated by vegetable astringents, though tannin coagulates the watery combinations of mucus: neither does a concentrated solution of it gelatinise on cooling. Mucus is a constituent of most of the secretions of animals, particularly of the membranes termed mucous. It is deemed both nutritious and of easy digestion. Osmazome, animal extractive, or alcoholic extract of flesh, is deemed the principle to which meat owes its sapid taste and odour when dressed. Berzelius is disposed to refer these qualities to a watery extract of flesh, which he terms zomoidin. Osmazome is by no means a simple, but, on the contrary, a very compound substance, consisting of at least two different extractive materials, lactic acid, several salts, alkalies in combination with hydrochloric acid and lactic acid, &c. It is probably limited to the animal kingdom, though a substance strongly analogous to it is found in many mushrooms, or fungi, namely, the common mushroom (Agaricus campestris), the A. muscarius, A. bulbosus, A. thejogalus, and in the sporidia of the Elaphomyces officinalis. This principle is not soluble in alcohol, and to distinguish it from ozmazome it is termed Pilzosmazom; to it different fungi owe, when dressed, their savoury odour, resembling that of animal food, and probably a portion of their nutritious property. Osmazome exists sparingly in young and white meats, which consequently are deficient in savour; it is more abundant in that of animals of which the flesh is red, such as beef and mutton; it exists chiefly in the fibrous organs, or combined with fibrin in the muscles, but the tendons and gelatinous organs are, in a great measure, destitute of it. Animals with dark-coloured flesh, such as the hare, and different kinds of game, possess most, and hence are much esteemed by the lovers of savoury viands. Gluten is, of all vegetable principles which occur in considerable quantity, the one which contains most azote, having from 14 to 20 per cent. Cafeine, or the alkaloid of coffee, possesses a much larger proportion. Gluten is met with, associated with starch and other matters, in the seeds of the cereal grains, in several other seeds, in many fruits, and in all green and other sappy parts of plants which yield feculæ. When separated from the principles with which it is usually associated, it is, when moist, a white, soft, elastic, and highly glutinous substance (bird-lime); when dry, it is white or whitish gray, hard, of a dull shining and conchoidal fracture. It is without smell or taste, insoluble in and heavier than water. Under ordinary circumstances, about a fourth part of what is termed gluten consists of a principle called gliadin. What remains after the removal of this and other matters present with it, is, according to Taddei, pure gluten, which he names zymoian. In the fleshy seeds of pulse, such as beans and peas, exists a substance resembling gluten, called legumin and also vegeto-animal substance. Gluten is found in many esculent plants, such as the leaves of cabbages and cresses, and in other edible cruciferous vegetables. Of the nutritious powers of gluten, separate from the starch, fat, gliadin, &c., with which it is always associated, nothing certain is known. In a state of combination, such as that of wheat-flour, it is highly nutritious. Such also is the character of the seeds of peas, beans, and other edible pulse. Fluids which contain at the same time any of the varieties of sugar and of gluten, or gluten-like principles, are capable, under favourable circumstances, of undergoing the vinous fermentation. A kind of fermentation occurs, by the agency of the gluten, in the conversion of wheat-flour into bread. Emulsin (vegetable albumen, vegetable casein, or amygdalin) occurs in most of the elaborated juices of plants, and in many dry parts of plants, namely, in all oily seeds which when triturated with water form an emulsion. The real nature of this principle is not clearly ascertained. Many chemists deem it identical with animal albumen; others consider it identical with the casein of the milk of animals; while others pronounce it to be gluten. To Gmelin it appears distinct; he has accordingly given it the above name. Legumin is the term given to some forms of this principle. II. Proximate principles which consist of oxygen, hydrogen, and carbon, called hydro carbonates. Gum is a principle of vegetables, in all of which, but mostly in the soft parts of them, it is found; in some, however, it abounds so much as to form their chief characteristic: they are thence called mucilaginous, or gummy, such as the carrot, parsnip, &c. Gum is colourless, but from admixture of other matters it is often of a yellow or brownish hue, transparent or translucid, of an insipid rather sweetish taste, and not crystallisable. When pure, it is entirely soluble in water, whether warm or cold, forming with it a tenacious fluid; it is insoluble in alcohol. In the state of solution in which it occurs in plants, of which it forms the chief material for their nutriment, it is termed mucilage. From some trees, either by spontaneous cracks or incisions, it exudes and concretes on the bark, as is seen in the various acacias, which yield the gum arabic, the plum, and cherry trees, &c. There is some difference in chemical character in the various sorts of gum, according to the plant which yields it, but these scarcely affect its nutritive properties. The principle which is found in many fruits, such as the gooseberry, currant, orange, &c., which is vegetable jelly, is regarded as a kind of gum, though designated pectin. This is neither acid nor possessed of basic properties, and the reason why it so often seems sour is by being united with vegetable acids (malic, citric, &c.), which communicate to the juices of these fruits their taste, and also enable them to redden litmus paper. The grateful and cooling properties of such fruits is therefore chiefly due to the vegetable acids, while their nutritious qualities depend upon the pectin and other principles. Some of these, such as plums, apples, gooseberries, contain 73 to 80 per cent. of water. (See Johnston's 'Chemistry of Common Life.') Mucilaginous vegetables are rarely fit for use when growing wild; but they are much ameliorated by the processes of horticulture, having their bulk increased and their qualities improved; those which are bitter or narcotic, as endive, lettuce, sea-kale, &c., being by blanching rendered mild and safe, or by being served to table while young, as asparagus. The difference in flavour of such vegetables is due to the principles with which the gum is associated; but their nutritive properties are owing to the gum, which even when taken alone, though mawkish, and at last repudiated by the palate, is certainly adequate to the support of the human frame for many weeks or perhaps months. During the harvest of gum at Senegal the Africans live entirely upon it, eight ounces being the daily allowance for each man. In general they become plump on this fare, and indeed such should be the result, if the calculation be correct which assigns as great nutritive power to four ounces of gum as to one pound of bread. Sugar is a principle much more abundant in vegetable than animal fluids; it exists however in small quantity as a constituent of the bile, and in the milk of many animals; and it is formed in large quantity as a product of perverted action of the digestive and assimilating organs, in the disease termed diabetes. [DIABETES.] In chemical composition sugar does not differ greatly from gum, except in having a greater proportion of carbon. This additional proportion however is sufficient to confer upon it considerable differences in character. Sugar is of different kinds, according to the plant which yields it, and according to the part of the plant from which it is obtained. Sugars are therefore divided into those which are crystallisable and those which are not, and likewise into those which are susceptible of fermentation and those which are not so. The sugar of the sugar-cane is the most perfect example of those kinds which are both crystallisable and capable of undergoing fermentation; sugar of milk and mannite are examples of the second class. A remarkable feature presents itself in sugars of the first class; for, while susceptible, when dissolved in sufficient water, of the vinous or acetous fermentation, they greatly assist, when concentrated, in preserving vegetable substances, either when naturally present in them, as in many fruits, grapes, raisins, prunes, &c., or when added artificially in making conserves, jellies, &c. Those fruits which grow in seasons favourable to the elaboration of much saccharine matter in their tissues not only keep better, but are more wholesome than when grown in less favourable years. [SUGAR.] Honey contains a variety of sugar, which is both nourishing and capable by fermentation of yielding mead, which was long the favourite beverage of the ancient Briton. Many fungi, or mushrooms, contain a peculiar kind of sugar, which contributes to render them nutritious. Starch possesses a larger proportion of carbon than sugar and gum: by removal of this additional proportion of carbon it is reduced to the state of one or other of those principles. This process of reduction occurs spontaneously in the course of flowering in plants, and in the stomach during digestion. When combined with gluten, it is susceptible of fermentation, and by undergoing the panary fermentation forms bread, one of the most important articles of food in civilised life. As this is ordinarily managed, some portion of the flour is made to yield up a certain amount of its carbon; but the precise nature of the change which the flour undergoes during this action is not clearly understood. The digestibility of the flour is however greatly increased by this process; and by various admixtures, chiefly of common salt, the taste is improved. [BREAD.] Starch exists largely in plants, but more abundantly in some parts than others: such as many seeds, particularly of the cereal grains, rice, barley, maize, and millet, in which it occurs in great purity; in wheat along with gluten; with saccharine matter in oats, and some leguminous seeds; with a viscid mucilage in potatoes, rye, and Windsor beans, and occasionally with an acrid principle, which can generally be dissipated by heat, as for example the Jatropha Manihot, which yields tapioca. Though seeds and roots yielding starch in abundance are all comprehended under the term farinaceous, there are essential differences between them according to the principles with which it is associated, which cause them to differ in their digestibility, and consequently in their eligibility and suitableness for different ages and individuals. Flour, starch, arrow-root, cassada-flour, or tapioca, salep, sago, and other similar preparations, are all merely varieties of the same principle. Starch is not only highly nutritive, but one of the blandest and most wholesome articles of diet, capable, in due proportion, of being used for the food of tender infants, and not improper at any subsequent period of life, though during youth and manhood it requires other principles to be taken along with it. Oils and fat, however much unlike in some respects to the other principles arranged under this head, are formed out of precisely the same constituent elements; and during digestion the stomach brings even the most apparently dissimilar into a degree of relationship more intimate than might have been anticipated. The chief difference between them and the alimentary substances already mentioned, is in their greater proportion of hydrogen. Sugar and starch are both susceptible of fermentation, during which a portion of carbon is removed from each by combining with oxygen and escaping in the form of carbonic acid gas-from starch in the early stages of fermentation, during which a portion of carbon is taken which brings it to the state of sugar; from which again a proportion of carbon and of oxygen is taken, and alcohol produced, the hydrogen remaining undiminished in quantity :--and as alcohol is merely an oleaginous body of a weak kind, the analogy is complete; for all farinaceous and saccharine aliments undergo changes in the digestive organs before they can be assimilated in the system, similar to what occurs in fermentation, namely, being converted into oil. [DIGESTION.] Oils are insoluble in water, and therefore, though highly nutritive, they are not available for the support of the body till their immiscibility with water has been overcome. Hence they are apt to oppress the stomach during the early stages of digestion, if taken alone without being mingled with substances which facilitate their union with water. When this is accomplished they are very readily assimilated, as, according to Dr. Prout, “albuminous and oleaginous principles may be considered already fitted for the purposes of the animal economy without undergoing any essential change in their composition." Oils are either fluid or concrete, and both forms occur in the animal and vegetable kingdoms, though in the latter they are most generally fluid. Acids are present in many vegetable substances which affect the digestive organs in various ways, though they may not contribute directly to the nourishment of the system. III. Alimentary principles which do not contain carbon. Water is the only one of these which it is necessary to notice. This is essential to the existence of all organised beings in whatever way it is introduced into their tissues. Not only is it introduced by human beings in the state of common water, and many beverages of which the chief part is water, but our ordinary articles of animal food contain, on an average, 75 per cent. of water, and only 25 per cent. of nutritive matter; and many of our vegetables contain a still larger proportion. Such are the chief principles employed by man in a state of civilisation for his subsistence. But it is not enough that a sufficient quantity of one or more of these be swallowed. The function of digestion must be called into action to enable the crude materials to be assimilated. This is partly excited by the mere presence of a substance in the stomach, but more effectually when that substance is in itself of a stimulating quality, or is accompanied by certain accessories either added during the preparation of the food or at meal-times. Such accessories are termed condiments, which either make the food more grateful, or exercise a beneficial influence over the stomach during the process of digestion. The desire to eat is rarely so great when insipid food is offered to an individual as when savoury viands are presented. The very odour or aroma of these excites the salivary glands to more abundant secretion of saliva, which is a preparation for the digestion of the food about to be taken. Though the mere application of heat in the process of cooking developes an aroma from many substances which were previously devoid of it, either by altering the chemical composition of the material, or by volatilising a principle latent in the substance, yet many adventitious articles are used to assist in increasing or modifying this odour, or to correct certain qualities in particular kinds of food which are either disagreeable or injurious. Respecting the most common of these a few words may be allowed. That condiment which is of most universal requirement and utility is salt, or chloride of sodium. It is the only one which is indispensable, for not only does it exist in the milk which forms the earliest nutriment of the infant, but at all subsequent periods of life it is needed. Independently of the part which this compound performs in the stomach during digestion, it is still further serviceable in the blood, and more so in the blood of man than of any other being, as Berzelius has remarked that the blood of man contains three times more hydrochlorates than that of the ox. Besides, the use of salt greatly benefits the alimentary canal and hinders the generation of Worms. [ANTHELMINTICS.] It is one of the most ready means of rendering insipid food acceptable to the palate, as is noticed in one of the earliest compositions that have come down to us. "Can that which is unsavoury be eaten without salt?" (Job vi. 6.) Perhaps the next most important condiment is vinegar, which, like most vegetable acids, when taken in moderation, greatly assists in promoting the digestion of young meats of a gelatinous kind, such as veal. Mustard and pepper of different kinds are also useful, and more so in warm than cold countries, as they rouse the languid stomach, and enable it to effect the digestion of the food. Hot pickles, from containing vinegar at the same time, are often advantageous when used in moderation, but the abuse of such articles produces many serious effects, particularly obstruction of the liver, with its long train of disorders. The use of spices and aromatic agents not only renders the food more pleasant but enables the stomach to bear a larger quantity. Hence they are too often made the means of leading the gourmand to be guilty of excess; and that cook is often most prized who can most cunningly minister to the pampered appetite. This is perverting cookery, a highly proper and commendable art, from its legitimate end. "In the hands of an expert cook, alimentary substances are made almost entirely to change their nature, their form, consistence, odour, savour, chemical composition, &c.; every thing is so modified that it is often impossible for the most exquisite sense of taste to recognise the substance which makes up the bases of certain dishes. The greatest utility of the kitchen consists in making the food agreeable to the senses, and rendering it easy of digestion. But its perfection seldom stops here: frequently among people advanced in civilisation the object to which it aspires is to excite the appetite, to appease eapricious palates, or to satisfy luxurious vanity. Then, far from cookery being a useful art, it becomes a real pestilence, carrying with it a train of diseases, and not unfrequently the premature death of many of its infatuated votaries." (Majendie's 'Physiology.') [MILK; WATER; WINE.] A few remarks are appended to serve as a guide in the use of food and to avoid errors. Though man is omnivorous, and can subsist on either animal or vegetable food-an arrangement which fits him to dwell in any part of the habitable globe, yet he is subject with regard to the actual material of his diet, in a remarkable manner, to the influence of climate, since a particular kind of aliment, which is very appropriate in one country is improper in another; thus, as we advance from the equator towards the poles, the necessity for animal food, or its equivalent in a highly nitrogenous class of vegetables, becomes greater, till, in the very north, it is the sole article of subsistence, except a few cruciferous plants, especially cochlearia or scurvygrass, abounding in nitrogen. Animal food, from containing nitrogen, is more stimulating, and, therefore, less suitable for hot climates, where, on the contrary, saccharine, mucilaginous, and starchy materials are preferred; hence, in the zone of the tropics, we find produced in abundance, rice, maize, millet, sago, salep, arrow-root, potatoes, breadfruit, banana, and other watery and mucilaginous fruits. Quitting this zone, we enter that which produces wheat, and here, where the temperature is lower, we find united with the starch of this grain that peculiar vegetable principle (gluten) possessing all the properties of animal matter, and yielding nitrogen and ammonia by its decomposition. Thus, by a gradual and insensible transition, nature furnishes to man the food which is most appropriate for him in each region. In the subtropical zone vegetable diet is still preferred, but, in chemical composition, the favourite articles approximate animal substances. This holds also in the temperate zone, not only in respect of wheat, but also in the chesnut, which is almost the sole means of subsistence in some of the mountainous regions of France, Italy, and Spain, though instead of the gluten of wheat, this seed contains albumen, the relation of which to animal food is even closer than that of gluten. In reviewing the geographical distribution of the cereal grains, we find that starch nearly pure is produced in the greatest abundance in the hottest parts of the world, particularly in rice and maize; it becomes associated in the subtropical regions with an equivalent for animal food; and in still colder regions, where wheat fails, oats and barley take its place. These, though possessed of less gluten than wheat, are, nevertheless more heating, and therefore, better calculated for northern latitudes. The inhabitants of Scotland and Lapland, with their oaten and barley or rye bread, are thus as thoroughly provided |