1M 



rooa 



rooD 



1W 



likewise solidified by many acid*, such a* that of the gastric juice (in 

 the form of rennet), and by aoma metallic lalt*. Milk, though eoagu- 

 laud by aciiU, in not ao by boiling. 



Albumen U likewua found in the green feculic of planU in general, 

 and in aome vegetable* in very conaiderable quantity, auch as the fruit 

 of the llibiKiu umlmtiti, or OeAro, and the bark of the irimut ram- 

 pettrit, or elm. The former U used in Sicily to thicken soups, and 

 both are uaed in the Weat Indiea to clarify sugar. 



Animal cattuu, the portion of milk which is coagulated by rennet, 

 lad aome aciiU 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 

 principle) present Theae are neutralised by the acids. 



Gttali" abounds in most animal substances, and U common in pro- 

 portion 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 anirn'r'* The skin of fish, much of their substance, and the swim- 

 ming-bladder of the sturgeon, are formed of gelatin. It is remarkably 

 bland and nearly insipid, as may be remarked in any solution of 

 iategUa*. Gelatin is not of common occurrence in the vegetable 

 kingdom, and it is distinct from vegetable jelly. It occurs, however, 

 in the Protococciu nivalu. 



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 U, in popular estimation, 

 much overrated. 



MUCH* is a principle probably found only in animal structures, 

 unless it exists in some plants of the tribe of Hurayiuacfr. 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. 



Onutzomt, 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 :omidiit. 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, Ac. 



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 (Ayaric** campettrii), the A. mutcariui, A. 

 bultwms, A. ttujagalta, and in the sppridia of the Elapkonyea offici- 

 nalii. This principle is not soluble in alcohol, and to distinguish it 

 from oznuusome 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 con- 

 sequently are deficient in savour; it is more abundant in that of 

 niml. of which the flesh if red, such as beef and mutton ; it exists 

 chiefly in the fibrous organs, or combined with fibrin in tho muscles, 

 but the tendons and gelatinous organs are, in a great measure, il. 

 of it Animals with dork-coloured flesh, such as the hare, and dillerent 

 kinds of game, possess most, and hence are much esteemed by the 

 lovers of savoury viands. 



(ijutr* 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 feculiP. 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 cunchoidal fracture. It is without smell 

 or taste, insoluble in and heavier than water. Uml.-r ordinary cir- 

 cumstances, about a fourth port of what is termed gluten consists of a 

 principle called glimlin. What remains after the removal of thin 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 leynmin and also 

 rtffdo-animal lubHanre. 



Gluten is found in many esculent plants, such as the leaves of 

 cabbages and creases, and in other edible cruciferous vegetables. Of the 

 nutritions powers of gluten, separate from the starch, Jat. gliodin, Ac., 

 with which it is always associated, nothing certain is known. In a 

 state of combination, sach as that of wheat-flour, it is highly nutri- 

 tion*. Such also is the character of the seeds of pea*, 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, ore 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. 



t'mulri* (vegetable albumen, vegetable casein, or amygdolin) occur* 

 in most of the elaborated juice* of plants, and in many dry parts of 

 plant*, namely, in all oily seeds which when triturated with water 

 form an emulsion. The real nature of this principle is not clearly 

 ascertained. Many chemist* deem it identical with animal albumen ; 

 others consider it identical with the casein of the milk of animals; 

 while other* pronounce it to be gluten. To Gmelin it appears di 

 he has accordingly given it the above name. Legumin U the term 

 given to some form* of this principle; 



11. Proximate principles which consist of oxygen, hydrogen, and 

 carbon, called hydro-carbonates. 



(inn is a principle of vegetables, in all of which, but mostly in tho 

 soft port* of them, it is found ; in some, however, it abounds so much a* 

 to form their chief characteristic : they are thencu called mucilaginous, 

 or gummy, such as the carrot, parsnip, Ac. Gum is colourless, but 

 from admixture of other matters it is often of a yellow or l>rowniah 

 hue, transparent or tran/tlucid, of an insipid rather sweetish taste, 

 and not crystaUisable. Wlu-n 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 form* the chief material for their nutriment, it is termed 

 mucilage. From some trees, either by spontaneous cracks or in. 

 it exudes and concretes on the bark, as is seen in the various acacias, 

 which yield tho yum arabif, the plum, and cherry trees, Ac. Tl. 

 some difference^ in chemical character in the various sorts of gum, 

 according to the plant which yields it, but these scarcely ai! 

 nutritive properties. The principle which is found in many fruits, 

 such as the gooseberry, currant, orange, Ac., which is rtgtlatile J 

 regarded as a kind of gum, though designated jxrti*. 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, 

 Ac.), which communicate to the juices of these fruiU their taste, and 

 ohm enable them to redden litmus paper. The grateful and < 

 properties of such fruit* U therefore chiefly due to the vegetable 

 while their nutritious qualities depend upon the pectin and other 

 piiii.-iples. Some of these, such as plums, apples, gooseberries, con- 

 tain 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, lia\ niL.-tli.-ir 

 bulk increased and their qualities improved ; those which are bitter 

 or narcotic, as endive, lettuce, sea-kale, Ac., being by blaiu-hing ren- 

 dered 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 tho gum is associated; but their nutritr 

 perties 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 fore, 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. 



/is a principle much more abundant in veget. .!]. tli;m ..njin.il 

 fluids; it exists however in small quantity as a constituent. 

 bile, and in the milk of many animals; and it in formed in large 

 quantity as a product of perverted action of the digestive and assimi- 

 lating organs, in the disease termed diabetes. [DIABETES.] In eli.-mi- 

 cal 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 arc crystal- 

 lisable and those which are not, and likewise into those which are sus- 

 ceptible of fermentation and those which are not so. The sugar of the 

 sugar-cane is the most perfect example of those kinds wl. 

 crystollisable and capable of undergoing fermentation ; sugar of milk 

 and mannite are examples of the second class. A remarknlile t 

 presents itself in sugars of the first class; for, while susceptible, when 

 dissolved in sufficient water, of the vinous or acetous fcnn.-i 

 they greatly assist, when concentrated, in preserving vegetable sub- 

 stances, either when naturally present in them, as in many fruits-, 

 grapes, raisins, prunes, Ac., or when added artificially in making con- 

 serves, jellies, Ac. 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 favour- 

 able years. [SI-GAR.] 



Honey contains a variety of sugar, which is both nourishing and 

 capable by fermentation of yielding mead, which was long the favourite 

 beverage of tho ancient Briton. Many fungi, or mushrooms, contain a 

 peculiar kind of sugar, which contributes to render them nutritious. 



/i 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 re.! 

 occurs spontineously in tho course of flowering in plants, and in (lie 



