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in southern climates contain much and as fat is indispensable to such less carbon than the train-oil eaten in repair, we can therein see one source polar regions, would be a tolerable of the demand for fat. Besides subexample, if only fruits were eaten in serving this end, fat will also assist the one; but the Sicilian and Neapo- animal heat in virtue of its low conlitan eats more oil than the Swede, ducting power retarding the loss of and his macaropi is a highly car- temperature. Oil the body externally, bonised substance ; and the Hindoo and you efficiently protect it from subsists on rice and butter-sub- cold. The reader will bear in mind, stances highly carbonised, and classed that we are not disputing the position as chiefly respiratory, furnishing in that fat is burned in the body, or superabundance that very heat which that it is not one important source of his climate renders so undesirable. animal heat; far from it; the point According to theory, the Hindoo disputed is, whether fat is only a should eat very little non-nitrogen-heat-producer, and the demand for it ous food, and be content with plastic in cold countries only a demand for substances, since he wastes his tis- combustible material. On this point sues in daily labour, but does not it is well worthy of remark, that stand in need of any surplus heat; Schmidt's researches prove fat to be whereas, according to fact, he eats less easily combustible in the blood very little nitrogenous food, and a than the carbo-hydrates, and even great deal of “ heat-making” food. than the albuminates it so that the And this damaging fact is brought Hindoo, in his rice, eats a substance into even greater relief by the expe- more immediately oxidisable in the riments of Messrs Lawes and Gil- blood than the tallow eaten by the bert (who nevertheless do not seem Esquimaux; and if fat be demanded to oppose the theory), as thus re- in cold countries, only to supply anicorded by them : " The weather, mal heat, that supply would be better during part of the period of this afforded by starchy substances, were second series of experiments, was the chemical hypothesis the true one. exceedingly hot ; from this several of What has been already said will the animals suffered considerably; perhaps suffice to show how untenand some, either from this or other able a position is that which denies causes,

became quite ill, and died, or nutritive value to fats, sugars, starch,

killed to save their lives. water, &c., throwing the whole burden Nevertheless it is seen that there was of nutrition on the albuminous subupon the whole a larger amount of stances; it may complete the overrespiratory food consumed in relation throw of that position if I now show to weight in this series than in the that while the fats are tissue-makers, previous one, during the cooler sea- and heat-producers, the albuminates

."* Against such evidence as this, are heat-producers, and tissue-makers. the respiratory nature of non-nitru- No one doubts that heat is evolved genous food is more than equivocal. in the chemical changes which albu

It is a fact that, in cold countries, mivates undergo; the doubt raised fat and oil are greedily devoured ; can only be as to the amount. Liebig and it is the most striking fact that says :Liebig can adduce in his favour. But we have yet to learn that fat is sim- If the combustible elements of the ply so much “ combustible” material. plastic constituents of food served for The demand for fat in cold countries

the production of heat, the whole amount

of the substances consumed by the horse may arise out of various conditions. Increase of cold causes increased ac

in his hay and oats, by the pig in its tivity of respiration, and increased potatoes, could ouly suffice to support

their respiratory process, and conseactivity of muscular exertion. These quently their animal heat, in the horse cause a greater waste of tissue; con- for 4 hours daily, in the pig for 4 hours sequently increased repair is needed; daily ; or if confined to plastic food, they

were

son.

Report, p. 340. + See on this point, LEHMANN, Lehrbuch der Physiol. Chemie, 2d edition, iii. 203 and 386.

would require to consume five or six problems it is very brilliant. Nevertimes as much of it. But even in this theless, when we study what takes last case it is exceedingly doubtful place in the organism, we find direct whether these substances, considering and unequivocal contradiction given their properties, would in the circum; to each separate clause of the theory. stances under which they are presented We find on the one hand that races to oxygen in the organism produce the

of men live for considerable periods necessary temperature of the body and compensate for the loss of heat ; for of

on animal flesh alone—and this, being all organic compounds, the plastic con

the flesh of wild animals, contains stituents of food are those which possess

very little fat, even in comparison in the lowest degree the properties of with butchers' meat, which does not combustibility, and of developing heat contain much ; yet these men lead by their oxidation.”*

an active life, respire vigorously, and Every chemist would echo this need abundant animal heat ; so that statement, because Chemistry teaches nitrogenous food must to them be that of all the elements of the ani- amply sufficient for the temperamal body nitrogen has perhaps the ture of the body. On the other hand,

we find races of men living always on feeblest attraction for

oxygen; not only so, but it even deprives 'other vegetable food, containing little nitrosubstances, with which it combines,

gen, and in climates where a superof their tendency to unite with oxy- needed; so that to them non-nitro

abundance of animal heat is not gen. Phosphorus, for example, has an

genous food must be sufficient for the eager affinity for oxygen, as we know from its ready combustibility in at

chief supply of nutrition. And not mospheric air at ordinary tempera- only do these massive facts overtures ; but when combined with power the chemical hypothesis, but

even Chemistry itself, when internitrogen its combustibility is so difficult that it can only be effected

at rogating the facts of organic life, disred heat and in oxygen gas. Liebig of albuminates for oxygen, out of the

covers that, however weak the affinity hence concludes, and from the chemi- blood, its affinity, in the blood, surcal point of view is justified in concluding, that precisely the same rela- passes that of fat. Schmidt, to whose tions are preserved in the blood. The debted, found that on feeding cats

experiments science is so deeply inalbuminous (nitrogenous) bodies have, he says, but a very slight affinity for fat alone, or with much fat and little

now with flesh alone, and now with oxygen.

flesh, the albuminates were always “If the albumen of the blood, which

more rapidly destroyed than the fat, is derived from the plastic portion of the which was at first stored up in the food, possessed in a higher degree the body to be afterwards gradually power of supporting respiration, it would oxidised ; and these experiments are be utterly unfit for the process of nutrition. Were albumen as such destruc

confirmed by Persoz in fattening tible, or liable to be altered in the circu- geese with maize : the blood of the lation, by the inhaled oxygen, the rela- fattened geese was very rich in fat, tively small quantity of it, daily supplied but notably impoverished in albuto the blood by the digestive organs, men; the quantity of muscular subwould quickly disappear. As long as the stance was much diminished, and blood contains, besides albumen, other when the fattening was rapid the substances which surpass it in attraction weight of the whole body was absofor oxygen, so long will the oxygen be lutely diminished.t unable to exert a destructive action on

To the chemist these results will this the chief constituent of the blood; be paradoxical, if not inconceivable, and the significance of the non-nitrogen- and he will doubtless point to the ous food is thus made clear."

well-ascertained fact that in starvaIt is not surprising that a theory tion it is the fat which disappears so logical should have gained general first, and the muscles only yield up acceptance ; and as a specimen of their elements to destruction when chemical reasoning on physiological most of the fat has been oxidised.

* LIEBIG, Chemical Letters, 372. + LEHMANN, Physiol. Chemie, iii. 386.

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This point has already been dwelt nearly equal in the two series; yet on by us when treating of HUNGER that of the nitrogenous constituents and THIRST. All that can here be varies in the proportion of from three said is, that it needs to be recon- to stwo !” Again : “In the fourth ciled with the seemingly contradice pen where there was by far the largest tory facts; and when we come to amount of nitrogen consumed the understand more of the conditions of animals löst weight; and in the other organic substances in various parts three pens the productiveness of the of the organism, we may under- food is in the inverse order of the stand how it is that fat which is amounts of nitrogen taken in the scarcely oxidisable in the blood may food. Indeed, we believe that an be readily oxidisable in the tissues. unusually high percentage of nitroHow slow we should be in conclud- gen in succulent produce is frequenting from what takes place out of the ly a pretty sure indication of imorganism, to what takes place in it, maturity and innutritious qualities. is taught us in a hundred physio- Summing up the results of their logical facts: thus the fat which can whole series of experiments, the be decomposed into fatty acid and largest yet instituted, they declare glycerine by means only of the most that it is “ their available non-nienergetic acids and alkalis in the trogenous constituents rather than laboratory, is thus changed in the their richness in nitrogenous ones organism by the pancreatic juice, that measure both the amount conwhich has but feeble chemical pro- sumed to a given weight of animal, perties, but which brings about the in a given time, and the increase in result by means of an organic sub- weight obtained.” + And they refer stance acting as a ferment.*

to the instinctive preference given by We might multiply to a great extent the under-fed labouring classes to the objections which present them- fat meat, such as pork, over those selves to Liebig's theory of Food, meats which are leaner and more but those already stated are suffi- nitrogenous. cient to show that it is erroneous in Long as we have tarried over this every particular, in spite of its logi- part of our subject, the time will not cal dependence and plausibility. The have been misspent if it have clearly only extensive series of experiments impressed the conviction that nitroon feeding, with which we are acquaint- genous food is not the exclusively ed, as immediately serviceable, are plastic food, and that per-centages of those instituted by Messrs Lawes nitrogen afford no nutritive standard and Gilbert, and to them the reader --the conviction that Liebig's classiis referred ; because, although they fication is fundamentally and circumare by no means such as, from stantially erroneous and dangerousthe nature of the experiments, can and the conviction that Chemistry is give Physiology any accurate data, wholly incompetent to solve the prothey are valuable as practical results, blem of Food. and utterly destructive of Liebig's As soon as we relinquish the theory. They show among other seductive notion of physiological things that “although pigs were satis- deduction from chemical laws, and fied to eat a smaller proportion of place ourselves at the proper point food in relation to their weight, in of view, namely, that of the

organism those pens where the proportion of to be nourished, our classification of nitrogen was comparatively large, Food speedily falls under two main yet the proportion of increase to the divisions — Inorganic and Organic food consumed was less than where substances; and, doubtless to the the amount of non-nitrogenous food reader's surprise, the Inorganic turns consumed was greater." And fur- out to be the more important of the ther, that “whilst the non-nitrogen- two, supposing always that a question ous substance consumed to produce of degree can lawfully be entertained 100 lb. increase in weight is very where both kinds are indispensable.

Cours de 1854-55,

P. 391.

Claude BERNARD, Leçons de Physiologie Expérimentale.

+ Report, p. 344. VOL. LXXXIII—NO. DIX.

2 A

We are not, indeed, accustomed to disturb so elegant a formula ; yet consider minerals as food, or water the truth must be told, and the truth as highly nutritious; but that is is, that not a single statement so because we are not accustomed to expressed is altogether correct. Cerconsider the subject with the need- tain it is that Plants can, and do, ful accuracy. Tell the first man you convert inorganic substances into the meet that water is on the whole more organic, but it is not less certain nutritious than roast-beef, and that that this power is very limited, all common salt, or bone-ash, is as much except the simplest (perhaps not even an edible as the white of egg, and it these) needing organic principles to is probable that he will throw anxious be yielded by the soil in which they glances across the streets to assure grow. This destroys the distinction himself your keeper is at hand. between Plants and Animals, by Make the same statements to the showing that both, more or less, first man of science you meet, and depend on organic substances. It is the chances are, that he will think this inability in Plants to dispense you very ignorant of organic chemis- with organic matter that renders try, or that you are playing with a manure necessary.t While so much paradox.* Nevertheless, it is de- is certain, the general assumption is, monstrably true, and never would that Animals are altogether incapable have worn the air of a paradox, if of converting any inorganic materials men had steadily conceived the into organic; and are rigorously denature of an alimentary substance. pendent on Plants for every organic That is an aliment, which nourishes; substance met with in their bodies. whatever we find in the organism, This assumption seems to me wholly as a constant and integral element, unwarranted by any decisive knoweither forming part of its structuré ledge yet obtained. The main arguor one of the conditions of vital pro- ment on which it rests, namely, that cesses, that, and that only, deserves unless organic substances be given in the name of aliment. But we have the food, and in certain proportions, been seduced from this simple con- the animal perishes of starvation, ception, partly by vain endeavours to has no longer any coercive force when ascertain in analyses of food and we reflect that starvation as ineviexcreta what are the truly nutritive tably follows if inorganic substances substances, and partly by misconcep- be with held.I Organic substancestions of the processes of Nutrition. of a low order it is true-have been

Of these latter there is one, widely manufactured by the chemist out of spread, which declares, that while inorganic substances; and if alcohol Plants are able to nourish themselves and urea are already capable of directly by inorganic materials fur- being made in the laboratory, I nished them in the air, earth, and

reason for supposing that water, Animals are incapable of thus even more complex substances may drawing nourishment from inorganic not be made in the vital organism, materials, but depend solely on the the seat of such incessant chemical organic materials prepared for them transformation. Be this as it may, by Plants.

The Plants feed on the distinction between Animals and minerals, the Herbivora feed Plants falls to the ground when we Plants, and the Carnivora on the see that Plants do require organic Herbivora. The cycle is complete, substances, and that Animals do the symmetry of nature is perfect. nourish themselves with inorganic One feels a kind of pity in having to substances taken directly from earth,

see no

on

* “Minerals are not in the least alimentary, although many animals often eat them mixed with or combined with their food."-TIEDEMANN : Physiologie, i. 230.

+ VERDEIL and Risler have ascertained that all fertile soils contain a soluble organic substance resulting from the decomposition of vegetable matter.-Comples Rendus de la Société de Biologie, iv. 111-112.

# The necessity for organic food will be better understood when we come to speak of Digestion, and the action of nitrogenous substances as ferments.

§ LEHMANN is of the same opinion.— Physiol. Chemie, iii. 180.

92

air, and water. We hew salt from culty healed (sometimes not at all), the quarry to cast it in handfuls upon simply because their phosphate of our stews and soups, or in pinches lime has been diminished by the deon our meat and potatoes. We draw mands of the child. A similar effect water from the spring to drink ; and, is noticeable in infants during teethlike the plants, we draw gases (oxygen, ing, a period when the rickets perhaps also nitrogen) from the air, often make their dreaded appearance. to enter into those various combina- But still more fatal is the effect of tions without which no life is possible. withholding this salt from the food, It may be unusual to call these nutri- as we learn in the striking experitive principles, but if unusual it is not ments of Chossat, who withheld it unscientific. If “to nourish the body" from pigeons, allowing them to eat mean to sustain its force and repair no more than was contained in the its waste-if food enters into the liv- grain and water on which he fed ing structure--and if all the integral them : they all perished miserably, constituents of that structure are after attacks of diarrhea and softenderived from food—there can be no- ing of the bones.* thing improper in designating as The absolute necessity of a supply nutritious, substances which have an of inorganic materials in Food is furenormous preponderance among the ther illustrated in one of the experiintegral constituents. People who ments of Messrs Lawes and Gilbert, think it paradoxical to call water who note that Food, will cease their surprise on learning that water forms two-thirds

“ the pigs in pen 5, where Indian meal of the living body; and they will per- with large tumours breaking out on their

alone was given, had become affected haps cease to marvel at the nutritive necks, their breathing and swallowing value here attributed to minerals, becoming at the same time difficult ; we, on learning that when all the water

in order to test the question as to wheis eliminated, and the solids which ther this arose from the defect of nitroform the remaining one-third are gen or from other causes, supplied them analysed, they are found to contain with a trough of mineral substances : no less than one-third of mineral they soon recovered from their complaint, substances which remain as ashes. and eventually proved to be among the

fattest and best of the entire series of Nor must the presence of these mineral substances be regarded as acciden- pigs, at least a dealer in pork, with a tal or unimportant. They are con

practised eye, purchased, by preference,

one of these animals from among the stant, constituent, essential. Blood is

whole set of carcasses. The mineral mixnot blood without its salts and iron; ture supplied to them was composed of bone is not bone without its phos- twenty parts coal-ashes, four parts comphates; muscle is not muscle without mon salt, and one part superphosphate its salts.

of lime ; and for it they seemed to exLet us glance at one or two of these hibit considerable relish.” + inorganic elements; and, first, at phosphate of lime. There is not a

The point is forcibly put by Liesingle humour, nor a single tissue in big = the body, which without a certain “In the two preceding letters, there proportion of this salt. By removing has been ascribed to certain constituents it, the integrity of the tissue is de- of seeds, tubers, roots, herbs, fruits, and stroyed, and all characteristic pro

flesh, the power of supporting the pro

cesses of nutrition and respiration ; and perties as infallibly altered as if the organic elements were removed. If diction when it is stated that no one of

it will appear as a very striking contrathe needful quantity be withheld or these substances by itself, neither caseine withdrawn, the bones become weak- alone, nor the substance of muscular ened, as we see in pregnant women, fibre, nor the albumen of eggs or of the whose fractured limbs are with diffi- blood, nor the corresponding vegetable

* Von Bibra found that the quantity of phosphate of lime contained in the bones was determined by their ratio of work; those of the legs and feet containing more than the arms and hands, and both these more than the ribs or the passive bones.

+ Report, p. 339.

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