Food : its composition and nutritive value

Book I. By

BARBARA WALLACE

MEMBER OF THE LECTURERS* ASSOCIATION, ORGANIZING COOKERY LECTURER FOR SCHOOLS AND CLASSES’, ALSO LECTURER ON COOKERY, HYGIENE, ETC.,

AT THE PRINCIPAL LITERARY AND SCIENTIFIC INSTITUTIONS OF GREAT BRITAIN.

GOTHARD,

LONDON:

W. STEWART & CO., THE HOLBORN VIADUCT STERS, E.C.

EDINBURGH AND GLASGOW: J. MENZIES & GO.

Contents

CHAP PAGE

I. Food : its Principles, Classification, Sources, . 5

II. The Composition of Vegetable Foods, ... 8

Chapter I. Food : Its Principles, Classification, Sources.1

1. Food is derived from the Ger. Fuller , and signifies all solid and liquid substances used for the support, nourishment, and health of the body — i.e. all substances that can be digested or taken into the system to repair the daily waste of the body, which is termed, in physiological science, ‘ the process of assimilation.’

2. The principles of food are composed of various substances or properties, which the science of chemistry has discovered. The chief of these are —

Albumen.

Acids.

Alcohol.

Amygdalin.

Asparagin.

Benzoin.

Berberine.

Brimstone.

Butyrine.

Cafeine.

Calcium.

Casein.

Carbon.

Cellulose.

Citric Acid.

1 The following abbreviations will be used throughout the work: — L .= Latin; Gk .—Greek; Ger .= German; l.=ltalian; Sp. = Spanish j Fr. —French.

G FOOD : ITS PRINCIPLES,

Chlorine.

Legumen.

Piperine.

Chondrin.

Lignose.

Phosphates.

Dextrine.

Lime.

Potash.

Dextrose.

Lupulin.

Ptheime.

Fibrin.

Manite.

Silica.

Gelatin.

Malic Acid.

Sodium.

Glucose.

Margarine.

Starches.

Glutin.

Mucilage.

Stearine.

Grape Sugar.

Mucin.

Sucrose.

Gum.

Morphia.

Sulphates.

Glycerine.

Narcotics.

Solaniue.

Haemoglobin.

Nitrogen.

Tannin.

Hydrogen.

Oleine.

Theine.

Iron.

Osmazone.

Theobromine.

Inosite.

Oxygen.

Vitelline.

Kreatin.

Palmatin.

Volatile oils.

Lactose.

Pectose.

Yeast.

Lsevulose.

Pepsin.

These substances are again divided into groups or classes, under the titles of — I. Nitrogenous or plastic foods — substances producing flesh and muscle; II. Carbonaceous or respiratory foods — substances giving heat ; III. Mineral Matter, which is last, but not the least valuable element in the foods of animal economy, whether of the human or brute creation.

3. The most simple, and decidedly the most important class of foods used by the human race, are the productions of the Vegetable World. Man can exist without animal , but not without vegetable foods. These dietetic substances are found — (1) In the stems, leaves, and flowers of plants ; as in rhubarb, lettuce, hops. (2) Esculent roots, tubers, bulbs, etc. ; as arrowroot, horse-radish, turnips, potatoes, onions. (3) Fruits, gourds, fungi, etc. ; as strawberries, vegetable marrows, mushrooms. (4) Cereals, seeds, and nuts;

CLASSIFICATION, SOURCES.

as wheat, peas, cocoa-nuts. (5) Barks, lichens, algae; as cinnamon, Iceland moss, Carrageen moss.

4. Foremost amongst the productions of the Animal Kingdom in general consumption iu this country ranks (1) Flesh meats; as beef, mutton, pork. (2) Fish; as herrings, trout, salmon, crabs. (3) Poultry, game, and wild animals; as turkeys, hares, hedgehogs, etc. (4) The productions from animals ; as cow’s milk, cheese, hen or plover’s eggs, rennet, etc.

5. From the Mineral Kingdom we obtain phosphates, salts, etc., as phosphate of lime (a bone-making substance), common salt.

6. There are liquid foods, of which Water is the principal, although it enters more or less into the composition of all solid foods.

TILE COMPOSITION OF

Chapter II. The Composition Of Vegetable Foods

1. Cellular Tissue, or Cellulose (from L. cella ), is a white fibrous substance composing the basis of plants. It is insoluble in water or spirits, but in sulphuric acid it is quickly dissolved. It is akin to starch in its chemical composition. In the earlier stages of its growth it is digestible, but in old vegetables it assumes a woody, stringy character, and firmer in the tissue. From this we glean an important fact, plainly demonstrated too, viz. that the foods we obtaiu from the vegetable world in the shape of leaves, stalks, roots, etc., are more digestible when young, before the cellulose has become hard tissue. An almost pure type of cellulose is exhibited in cotton and pith. Its character slightly alters in different plants; for instance, in the common nettle or the flax plant it is close and hard, whilst it presents another feature in the beetroot or potato, where we find it loose and softer : therefore the pulp of the two latter would in any stage of growth be more digestible than either of the former. Cellulose is capable of being changed into its own weight in sugar by the application of certain acids.

2. Starch is the next most important element we find in the composition of vegetable foods. Starch is in appearance white, glistening, grauulated, heavy rather than bulky, and crisp to the touch. The purest type we have is arrowroot. Each tiny grain of starch is covered by a membrane or sac. It is insoluble in

VEGETABLE FOODS.

cold water, but on tlie application of water heated from 200° to 212° F., the interior portions of the little granules begin to swell, extending the outer membranes to their utmost limits, finally bursting the envelopes and mixing freely with the water ; it then forms a glutinous, semi- opaque mass, which we term in household economy starch. The word starch, by the way, is derived from stark = stiff, firm, as it is used for stiffening linen. It is computed that there are over 75,000,000 lbs. of starch used in Great Britain weekly for laundry purposes alone. Starch foods require thoroughly mixing with the saliva during the process of mastication, when certain chemical changes take place, transforming the starch into dextrose or grape sugar. Such portions as are not thus converted are indigestible. It will be seen by this that starch is, like cellulose, capable of a chemical change, forming sugar. This has been perfected in Germany, where there are large factories carrying on a lucrative trade by transforming into golden syrup, starch (procured from the horse chestnut) and sulphuric acid.

3. Sucrose (L. saccharum ), pure sugar , is the next important substance apparent in our analysis of foods. We find saccharine matter present in the products of the vegetable, animal, and mineral worlds. Its value as a food is equal to starch, and like it, sugar is insufficient to support animal life without the addition of other principles. It is antiseptic, nutrient, demulcent, soluble in cold water. It is obtained for dietetic purposes in great quantities from the sugar - cane ( Saccharum officinarum ), cultivated in the West Indies, Brazils, etc. Also from the beetroot ( Bttci vulgaris ), Europe and North America; maple ( Acer saccharum ), America ; and various sugar grasses, such as the Imphee of Zululand, millet sugar grass of China, Egypt, etc. Maize or Indian corn (Zea maps), cut whilst green before the time of inflorescence, yields abundant quantities, whilst the inhabitants of the tropics procure from the various Palmacece sugar for dietary purposes or fermentation, for the extraction of spirit or wine making. Sugar has been made from jute, pine shavings, and other like curious substances.

There are also classes of sugars of which sucrose is the chief or leading type. Amongst these may be mentioned grape sugar , muscle sugar , manna sugar , malt sugar , etc.

4. Glucose or dextrose, grape sugar , is not so soluble as sucrose, nor does it crystallize as easily. It is the substance we find coagulated or hardened in the pudding raisins of everyday use.

5. Lsevulose is another branch of the grape sugar family. It is found abundant in honey and many ripe fruits. The grape sugars, although they play an important part in the assimilation of foods taken into the human system, are not so sweet as cane sugar. Glucose, or grape sugar, is rapidly formed when bread and cane sugar are eaten. All starchy and saccharine foods must be thus converted before assimilation takes place in the body.

6. Lactose, milk sugar , is that substance which imparts the sweet taste to milk. It is also capable of crystallization, and in that form is sold at the chemists, and chiefly used in the preparation of infants’ foods. Milk sugar is soluble in water but not in spirits.

7. Inosite, muscle sugar , is found in the flesh of animals. It is crystalline when dried. Inosite gives to horse flesh the sweet taste it possesses.

8. Manite, maltose, etc., are varieties of grape sugar. Sugar, like the diamond, is composed of a large proportion of carbon ; thus, when heated to a white heat, and the air excluded, it assumes the properties of a very hard graphite, capable of scratching on glass.

VEGETABLE FOODS.

9. Caramel is carbonized or burnt sugar, i.e. in the process of burning some of the water is evaporated, leaving the carbon principle more developed than in sucrose — greater, in fact, in bulk when compared in its former relation to the quantities of hydrogen and oxygen in its composition.

10. Oleine (Gk. elaion ; L. oleum), one of the four proximate principles of fat ( oleine , margarine, stearin e , glycerine ). Oleine is found in both animal and vegetable substances. Refined olive oil (Olea Etiropea) is the fairest type of oleine. Oils are of two kinds— -fixed or jat oils, and volatile or essential oils. Fixed oils are

chemically divided into two classes, viz. drying oils, i.e. those which will solidify or harden, as linseed and nut oils; unctuous oils, those which retain their liquid qualities, and do not become solid unless under the action of cold, as olive and rape oils. Unctuous oils become rancid by age. Fixed oils are relaxing and softening in their nature ; volatile oils stimulating, anti-spasmodic. The fat of bacon and pork is chiefly oleine, hence its liability to turn rancid or rusty. Oleine is one of the great heat -givers. Its qualities are

nutrient, demulcent, laxative, emollient. It is not soluble in water, is partly so in alcohol, and quite in ether. Oleine is the principal liquid component of butter.

11. Margarine, a fatty, solid substance. When olive oil is exposed to cold, little flakes are seen floating amongst the oil ; this is chemically known as margarine. It is found in suet, etc.1

1 Oleo margarine , from the * Far West,’ so well known to the American and English traders, is prepared from a mixture of (1) a large quantity of oil, ‘ adulterated ’ with forty or fifty per cent, of cream ; this is prepared by country dairymen, and requires an experienced, clever ‘ buyer ’ to detect it. (2) Oil is adulterated with just enough cream to allow of its being churned, in the proportion of one part cream to twenty of oil

12. Palmatine takes its name from the orangecoloured substance which forms the solid portion of the oil extracted from the kernels of a palm nut named Elais Guincensis. Palmatine quite dissolves in boiling ether, but its crystals are insoluble in water, alcohol, or cold ether. It is the solid fat found in butter, and is more frequently classed by chemical analysts as a proximate principle of fats and oils rather than margarine.

13. Stearine is the white, crystalline, semi-transparent, scale-like substance one sees glistening on the surface of a basin of dripping when cooled, especially the dripping from roast loin of mutton. It forms a large proportion of the solid matter of fixed fats. It is insoluble in water, but dissolves in ether and boiling spirits.

14. Glycerine (Gk. glukus, sweet) is the last mentioned and most useful of the four proximate principles of fats and oils. As cellulose is the basis of all plants, so glycerine is the foundation of all fats and oils. It combines quickly with water, and can be dissolved in alcohol. It has useful solvent powers, such as dissolving starches, acids, etc. Glycerine is a viscid liquid, quite colour-

This is a patent * butter ’ easily detected. The oil used is that produced generally from seeds of the cotton plant, ‘ cotton waste, ’ etc. (3) The representative of salt butter made from cleansed fats and oils. It is stated that over 2,000,000 lbs. per year of fat are drawn from the refuse of dead animals (cats, dogs, etc.) in Paris alone, and sent to be converted into butter ; whilst from Barren Island, the great emporium of bone dust, etc., near N ew York, many thousand tons per year are sent out. These vat shimmings, when cleansed, find their way into our markets as prime Devon butter, salt butter, butterine, and cheap lards, etc. The constituents of these butter substances, when ready for market, are not injurious to health, and have a nutritive value equal to the pure produce of cow’s milk. They keep sweet much longer than butter, and turn quite rancid on decaying ; never sour or acid in the first stages, like the lactic particles in milk butter.

VEGETABLE FOODS.

less when pure. As its name signifies, it is sweet to the taste, leaving a slight metallic, burning sensation in the mouth a few seconds after it has been swallowed. It is much used in cases of chest, throat, and lung diseases, as an internal remedy, whilst a similar principle, called vasceline , obtained from petroleum, is used outwardly. Glycerine is invaluable in cases of bronchitis, as it nourishes and heals. In an impure state this substance, as first extracted, is slightly coloured from the presence of extraneous matter. In its crude state it has many useful applications. Glycerine is rendered fit for domestic and medical purposes by the process of distillation. Animal charcoal is used for filtering it and clearing it from ammoniacal and volatile impurities. It is largely used to adulterate milk when mixed with water.

15. Bee’s Wax, eaten frequently with virgin honey, has the same constituents as fats and oils, but lacks the basis, viz. glycerine.

16. Dextrine is a gum-like substance found in all starch foods that have been heated above 300° F. Bread, beer, biscuits, and several patent foods which have been exposed to the action of heat during their preparation, contain dextrine. It is semi-transparent, and, like gum, soluble in water. A preparation of malt, flour, and sulphuric acid produces dextrine. This is known and sold as British gum.

Starchy foods are, during the process of digestion, changed for a period into dextrine.

17. Mucilage is another gum- like substance obtained from vegetable foods. It is chiefly extracted from seeds, roots, bulbs, and barks. The chemical constituents are similar to starch, and their heat-giving powers are equal. Mucilage is obtained by infusion of linseeds, marsh mallow roots, onions, etc.

18. Gum(Fr.^om?/je), a vegetable product almost like

H dextrine in appearance and character. The value of gum, mucilage, and others of the same class of substances as nutritive agents has been doubted by some analytical chemists, whilst by others the qualities of animal gelatine have been attributed to it. It takes, however, a standing point between the starches and sugars. It is found in many kinds of food, and no doubt plays its useful part in the human economy as an aliment. Gum is soluble in water, forming a viscid substance. It is insoluble in spirits or ether. Gum Arabic is the general example : it is transparent, tasteless, inclining from yellowish white to brown.

19. Mannite (Syrian mano , a gift) is another of the gum or semi-sugar-like substances. It is very sweet to the taste, of strong odour, and crystallizing on extraction from the manna juice, of which it is the essential principle. It will dissolve in water, but will not, like sucrose and other sugars, ferment.

20. Malic Acid (L. malum , an apple), a valuable acid in fruits and vegetables. For instance, the strawberry, pear, mountain ash, apple, etc., all contain malic acid. It is a blood purifier, food solvent, and has slight nutritive qualities. Rheine is an analogous substance found in rhubarb.

21. Citric Acid (L. citreum , citron) is that substance which gives the sour taste to lemons, citrons, and oranges. This acid is very wholesome, but some medical men ascribe to it injurious effects upon the system. When taken in large quantities, it is said to induce irregular palpitation and disease of the heart.

22. Acetic Acid (L. acetum , vinegar) is the most common vegetable acid. Vinegar is just acetic acid diluted with water. It is found ready formed in organic matter, but it may be produced by certain substances, such as alcohol, being mixed with azotized organic matter, exposed to the air to be oxygenized, when it rapidly

VEGETABLE FOODS.

becomes converted into acetic acid. The white wine vinegar one frequently purchases is in many cases guiltless of vinous extraction, and is obtained from ‘ destructive wood distillation,’ which produces a poisonous acid named pyroligneous acid; this is diluted with distilled water, and sold as the best French white wine vinegar. True acetic acid is obtained from malt and wine. It has a sharp, sour taste, and in its pure state will cauterize the mouth. It has the power of changing to a reddish colour vegetable blues.

23. Tartaric Acid is the organic acid principle found in grapes. It is obtained in a crude state in wine casks, and termed by some argol. It is the basis of various salts. When purified it forms cream of tartar.

24. Alcohol (Arabic a/, the ; Jcoohl, any volatile substance) is a colourless, limpid, stimulating, pungent liquid, having an aroma or bouquet. It never freezes, although it can be rendered gelatinous by exposure to intense cold. It boils at a much lower degree of temperature than water. It has only one source, i.e. fermentation of saccharine matter. A popular medical journal gives the following description of the nutritive qualities of alcohol : — 1 Liebig, Bouchardat, and others of our scientific men affirmed that alcohol was an aliment. However, in 1860, Lallemand, Perrin, and Duroy, men of known chemical ability, denied the statement, asserting that it passed unaltered through the system. These differences led to minute researches by very eminent analytical chemists, who ultimately discovered that alcohol, taken in small doses, was really consumed in the animal economy, and of decided nutritious value. It was also a source of warmth, and yielded materials for assimilation and renewal of tissue, increasing pulsation where it was sluggish. On the other hand, when taken in large quantities, the greater portion was eliminated unchanged, the pulsation became low and hard, and the temperature of the body lessened. It is for the latter cause it is given in fever cases. A good study of the negative side of the question can be obtained from our learned friend Dr. Richardson’s excellent little works on the subject.’

25. Theme, Cafeine, Theobromine, are also stimulants, found respectively in tea, coffee, and cocoa, which produce a direct effect on the brain, — most powerful, however, in tea and coffee, — although their influence on the muscular action of the heart and skin are exactly opposite. Tannin is also a vegetable product found and extracted from barks, fruits, leaves — as oak bark, grapes (skin), tea leaves. It is astringent and preservative, renewing the muscular tissue.

26. Asparagin is the crystalline principle. It is valuable as a blood purifier and diuretic.

27. Nitrogen (Gk. nitron , nitre ; gennao , I generate), a transparent, colourless gas, inactive when in a free state, but when in combination with other substances it displays energetic properties. It is an essential, proximate principle of animal and vegetable bodies. Nitrogen enters largely into the composition of all nutritive foods ; animals cannot exist on food which does not contain nitrogen. Again, all the nitrogenous foods are solid. Nitrogen is one of the gases constituting the atmosphere, so is a most important substance to animal life.

28. Albumen (L. albus , white), contained in animal and vegetable matter. It is a white, viscid substance, distinguished by becoming a solid when certain degrees of heat are applied, — for instance, in making beef tea we find a sort of curd, brown in colour, floating in the soup-like substance; that is mostly coagulated albumen. The white of an egg represents the purest type of albumen. The serum , or whitish liquor in the blood, is nearly all albumen. It is in the juice of flesh, sap of

VEGETABLE FOODS.

IT vegetables, seeds, etc. All foods containing albumen are known as albuminoids. It is calculated that 3000 lbs. of blood yield 110 lbs. of albumen for manufacturing purposes.

29. Protein is the foundation of all animal and vegetable cellular tissue. Casein, albumen, and fibrin are spoken of in some chemical works as proteinaceous substances.

30. Fibrin (L. fibra, a thread) is found in both blood and muscular tissue. When free it resembles long elastic filaments. It arranges itself into fibrous bundles. In blood drawn from living animals, the fibrin begins to coagulate on exposure to the atmosphere. The value of dried flesh, on analysis, was found to be almost identical with blood in its component parts. The value of blood fibrin as an article of restorative diet has long been known and prescribed by the Continental doctors, and in Paris particularly, where in the early morning, crowds of consumptive patients may be seen eagerly waiting for the draughts of warm blood dealt out at the abattoirs or slaughter-houses.

31. Phosphorus (Gk. phos, light; phoreo , I bring) occurs in organic matter. It abounds in cereals, seeds, roots, fruits, and fish (particularly in shell-fish), as wheat, barley, peas, beans, potatoes, apples, mackerel, lobsters, etc. Phosphorus is a great brain feeder taken in natural quantities and in combination with the foods iu which it exists, but the constant use of this substance in the form of pills, etc. and as a brain stimulator is not good, being apt to produce disease if the habit is persevered in. Phosphorus is found in blood, bone, albumen, nervous tissue, hair, etc., therefore we should so select our food that some portion of it should daily supply this very important element to the body.

32. Carbon (L. carbo , charcoal). On referring to the chemical symbols at the end of this work, it will be seen that carbon is one of the most important of organic elements, and is an elementary substance on which, in a greater or less degree, most of our foods are based. It is present in the vegetable, animal, and mineral kingdoms. A diamond is pure carbon crystallized. The greater part of coal consists of carbon. It is found, also, in combination with oxygen, in small quantities in air and spring water, and is in this form called carbonic acid. One of the most beautiful laws of nature is the absorption of carbonic acid by plants as food when cast out by animals, this substance being fatal to human but conducive to the welfare of plant life. Carbon is black, dense, opaque, tasteless, infusible, insoluble, inodorous, conducting heat badly and electricity freely. It is a digestive, antiseptic, and disinfectant agent. It is used in the forms of biscuits and lozenges as a remedy for indigestion. It is valuable as an antidote in cases of vegetable poisoning, especially when mixed with boiling water and taken as hot as possible. It counteracts animal putrefaction.

33. Hydrogen (Gk. hudor , water ; gennao , I produce) is an elementary substance ; it is gaseous, colourless, tasteless, and capable of liquefaction under certain circumstances. It is the lightest substance known, and enters into the structure of most of the articles used as daily food. In combination with oxygen it forms water.

34. Oxygen (Gk. oxas , acid ; gennao, I produce) is the most abundant of all the elementary substances. Eight-ninths of water is composed of oxygen and one quarter of the atmosphere. It is the most important element we have, as without it animal life could not exist. There is only one substance in which it does not unite, and that is fluorine. It is thrown out by plants when under the direct influence of the sun’s rays. It gives acidity to the substances iu which it predoini-

VEGETABLE FOODS.

nates. It exists nowhere in a pure state. Pure oxygen would be too stimulating for animal life.

35. Sulphur (L. sulphur , brimstone) is a valuable mineral substance, hard, brittle, and yellowish in colour. It is present in albumen, — the simple test of this is that it turns silver a greenish black. A spoon of this metal, used in an egg after it has been boiled, turns of this colour and discovers the presence of sulphur. It is a non-conductor of electricity : when heated or rubbed, it gives off a peculiar smell. It is the most powerful disinfectant known, and the only one which will effectually destroy the germs of infectious disease; whilst in the form of flowers of sulphur it is a certain cure in cases of typhoids, small-pox, diphtheria, etc.

36. Casein (L. cciseus , cheese). This is the nitrogenous principle found in milk, and forms the larger proportion of the substance known as curd. It somewhat resembles albumen in its composition. It is found in the yolk of eggs. A similar substance, known in chemistry as vegetable casein , is found in peas, beans, etc. Animal casein is not so easily digested as the vegetable substance which it resembles. It repairs the waste of muscle, and, taken in small quantities after meals, is supposed to act as a digestive agent. Acids quickly coagulate it, by, for instance, separating the butter and whey from the curd of milk.

37. Narcotic (Gk. narlce , stupor). This principle is found in many vegetable foods, as in lettuce, onion, hops, etc. It is sedative and soothing in its effects, giving a sleeping tendency, while it lulls or softens pain ; it also renders the process of digestion slower. It is useful if taken in the natural way, i.e. through the medium of foods such as the onion, especially to brain workers ; but if extracted from the poppy, or any other such opium or narcotic-yielding plant, and taken in the

B

VEGETABLE FOODS.

form of a drug, it is hurtful in the extreme to both mind and body. The use of a narcotic ought not to be indulged in without medical advice and in cases of disease.

38. Tannin (L. tann , an oak). This is a valuable astringent property found in vegetable substances. Its action on animal matter is well known by the process of tanning the raw hides of animals to preserve them from decay, by which means they become leather. The effect of tannin on the human system when taken in the form of food — as in tea, for instance — is to repair the waste of the tissues, and prevent decay of the body to a certain degree. Tannin also retards digestion ; therefore, if taken in combination with flesh meats, it might produce feelings of dyspepsia, but with fish it renders the meal more satisfying, as fish is much more rapidly digested than flesh foods.

VEGETABLE FOODS, ETC.

Chapter III. Vegetable Foods And Tiieir Nutritive Values

1. In the volume ■which it is intended shall follow this, the subject of the action of nitrogenous, carbonaceous, and mineral foods, with their several effects on the human system, will be duly considered. At present we will study the nutritive value of individual articles of food and their composition.

2. Vegetable foods, being man’s first and original food, will be taken as a primary example. And by way of introduction, we shall describe briefly the parts of a vegetable.

3. It is rather difficult to distinguish between the lower types of the animal and vegetable kingdoms. Physiologists disagree, with regard to some of the substances, as to which kingdom they pertain. Yeast is an example of this. Plants are made up of cellulose (see chap, ii.), and in the lower tribes there are few distinctive parts. They simply form a combination of leaves called the thallus , as in lichens and algse. If we examine plant life a few grades higher, we find very distinctive features which it is impossible to mistake.

(1) We have the Root, which fixes the plant to or in the ground, from whence it draws its nourishment by imbibing liquid foods from the earth, which are drawn up through the cellular tissue, and afford one of the means of plant life. Roots have a variety of forms. The root of a tree generally spreads itself like the upper branches of Ihe tree, whilst it throws out

VEGETABLE FOODS AND little fibres called j'ootlels. What we generally term the root of a potato is really an underground stem, and the fibres which come from the tubers or extended parts of the stems are really the roots.

(2) Stems are the central portion of the plant, and are found under ground as well as above. The suckers of the mint plant and couch grass illustrate these underground stems. They are composed of bundles of fibre, being either long, string-like collections of tissues, or deposited iu circles round a pithy cylinder. In a tree, the stem, being very large, is termed the trunk. This is encased by bark, which is cellular tissue dried and become hard from age. When a tree or plant has small substems, they are termed branches.

(3) Leaves grow from a small appendage attached to the branch called the leaf-bud. They assist in the feeding of the plant, and act as its lungs, absorbing certain substances from the air and so nourishing it ; whilst by means of the leaf waste substances are emitted by the plant useless to its vital energy, but of infinite value to the economy of animal life. Leaves consist of two parts, the stalk and blade. The latter has a variety of forms. It has in some plants a complete network of ribs and veins covering it, in others these run in parallel lines.

(4) Flowers consist of several parts : the outermost green scales are termed the calyx ; each part of this is called a sepal; within this is the corolla , which is the chief feature in the flower, viz. the coloured part. Then we have the petal , which is a single division of the corolla.