137 



FOOD. 



POOD. 



138 



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 ' Archseologia,' the 

 'Archaeological 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'Antiquite's Monumental,' vol. vi., and 

 ' Atlas,' Paris, 1841; and his ' Rudiment d'Arche'ologie 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 com- 

 pletely 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 con- 

 diments. 



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 substantial 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 hi 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 molecu/et, 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 gages are evolved, i 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 1 which consist of three are of moat frequent occurrence in 

 the vegetable kingdom ; those which consist of four are of most fre- 

 quent occurrence in the animal kingdom. Where the elements are 

 three only they are generally oxygen, hydrogen, and carbon ; where 



i nitrogen 



nitrogen is absent in animal matters the substance approximates, or is 

 analogous to, vegetable matter, such as animal fats, which closely 



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, pro- 

 vided 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. 



II. Those which contain carbon, hydrogen, and oxygen. 



III. Those which contain neither azote nor carbon. 



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 con- 

 stituents 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 considnrs 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 accom- 

 panying 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, be- 

 cause 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. 



AUnimen is another important constituent of animal bodies, but of 

 more sparing occurrence in vegetable substances. In animal sub- 

 stances 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 



