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in a physiological point of view, whatever we may think of them, will the only one really implicated-with continue their labours, analysing, scarcely any results at all. No one weighing, experimenting, and prodoubts that Food is a physiological pounding hypotheses ; and it is right question, inasmuch as it relates they should do so : all honour and simply to an organism. Never- success to them! But if the question theless, it has fallen into the hands of Food is to receive any practical of the chemists; and our treatises, solution, it must no longer be left in text-books, and even popular works, their hands; or only such details of have been encumbered by hypo- it left in their hands as properly theses which may amuse specula- belong to them. It must be taken tive ingenuity, but furnish very up by physiologists, who, while little positive result.. Against this availing themselves of every chemivice of Method, and this misdirection cal result, will carry these into of valuable labour, a voice should another sphere and test them by energetically be raised. The error another Method. Not a step can the is not a speculative error, simply : it physiologist advance without the is one carrying important conse- assistance of the chemist; but he quences; it either leads physicians must employ Chemistry as a means and farmers into serious mistakes, or of exploration, not of deduction—as leads them to throw up scientific a pillar, not a pinnaclean instruguidance in disgust, because the ment, not an aim. The chemist may hypothesis, so convincing on paper, analyse fat for him ; but he, on returns out stubbornly irreconcilable ceiving this analysis, will request the with fact. Let us not, however, be chemist not to trouble him with hypomisunderstood. In declaring the theses respecting the part played by chemical hypotheses on the subject fat in the organism : for although of Food to which Liebig, Dumas, the chemist may accurately estimate Boussingault, Payen, and others, the heat evolved in the oxidation of have given the sanction of their so much fat, the physiologist has to names, to be more of an encumbrance do with a vital laboratory, extremely than an illumination, there is no idea unlike that in which the chemist of undervaluing their labours. All works, and he has to ascertain how real work is important, no genuine the fat comports itself there. research is unworthy of our grati- Alimentary substances are subtude; but it is one thing to reverence stances which serve as nourishment; power, and respect the work achieved, but a great mistake is made when another thing to assign the nature it is imagined that their nutritive and position of that work. With value can chiefly reside in the regard to the vast chemical researches amounts of carbon, nitrogen, hydrointo the subject of Food which have gen, oxygen, and salts, which they occupied a quarter of a century, it contain; it resides in the relation seems to me that their value has which the several substances bear to been almost exclusively chemical, and the organism they are to nourish. only in an indirect and limited de- Music is not harmonious to the deaf, gree physiological. Hence, in spite nor is colour splendid to the blind. of the unanimity and apparent pre- The substance which nourishes one cision observable in the analyses and animal affords no nourishment to hypotheses offered by chemists, no another, nor will any table of “ nuimportant practical results have been tritive equivalents,” however precise, attained, not a single alimentary convince us that a substance ought problem has been solved by them. to nourish in virtue of its composi
There may be readers who, failing tion, when experience tells us that to see the ground of this distinction it does not nourish, in virtue of some between chemical and physiological defective relation between it and the investigations, will not understand organism. That “one man's meat the importance I attach to it; but is another man's poison” is a proverb they will perhaps come round to my of strict veracity. There are persons, point of view before this essay even in Europe, to whom a muttonreaches its close. The chemists, chop would be poisonous. The cele
brated case of the Abbé de Villedieu employed, they are soon undeceived
“ He could be altogether slighted, especially not eat mutton in any form. The when it takes the form of refusal; peculiarity was supposed to be because this caprice is probably owing to caprice, but the mutton nothing less than the expression of was repeatedly disguised and given a particular and temporary state to him unknown; but uniformly of his organism, which we should with the same result of producing do wrong to disregard. And whenviolent vomiting and diarrhæa. ever a refusal is constant, it indiAnd from the severity of the effects, cates a positive unfitness in the which were in fact those of a viru- Food. Only gross ignorance of Phylent poison, there can be little doubt siology, an ignorance unhappily too that if the use of mutton had been widely spread, can argue that because persisted in, it would soon have a certain article is wholesome to destroyed the life of the individual.” many, it must necessarily be wholeDr Pereira, who quotes this passage, some to all.
Each individual oradds, “ I know a gentleman who has ganism is specifically different from repeatedly had an attack of indi- every other. However much it may gestion after the use of roast mut- resemble others, it necessarily in some ton.” Some persons, it is known, points differs from them; and the cannot take coffee without vomiting; amount of these differences is often others are thrown into a general considerable. If the same wave of inflammation if they eat cherries or air striking upon the tympanum of gooseberries. Hahn relates of himn- two different men will produce sounds self that seven or eight strawberries to the one which to the other are would produce convulsions in him. inappreciable---if the same wave of Tissot says he could never swallow light will affect the vision of one sugar
without vomiting. Many man as that of red colour, while to persons are unable to eat eggs; and the vision of another it is no colour cakes or puddings having eggs in at all, how unreasonable is it to extheir composition, produce serious pect that the same substance will disturbances in such persons : if they bear precisely the same relation to are induced to eat them under false the alimentary canal of one man as to assurances of no eggs having been that of another! Experience tells
• Journal de Medicine. Août 1760, quoted by Lucas, De l'Hérédité, who is the authority for the next statement.
+ PEREIRA : Treatise on Food and Diet, p. 242.
that it is not so. A glance at the that our text-books are at once so preanimal kingdom reveals the striking cise, and so erroneous. Open almost differences manifested by two closely any work on Physiology or Organic allied organisms in their capability Chemistry, and you will meet with of assimilating the same substance. expositions of the theory of Food, There are two species of Rhinoceros, and the nutritive value of various the black and the white. The black aliments, which are so precise and so species feeds on the graceful, but unhesitating in their formulæ, that deadly, plant, Euphorbia candela- you will scarcely listen to us with brum, and converts it into its own patience when we assert that the presubstance; but if the white species cision is fallacious, and the doctrines happen to eat thereof, it is inevitably demonstrably erroneous. Neverthepoisoned. The Herbivora are divided less we hope, before concluding, to into two classes, the first subsisting .convince you that Chemistry is itself on a variety of plants, the second on in too imperfect a condition to give one kind only. But even the various clear and satisfactory answers to its feeders will not touch certain plants own questions in this direction-as eagerly devoured by others : thus Mulder and Lehmann frankly avow the horse passes over almost all the —and further, that Chemistry, even cruciferæ ; the ox all the labiates; supposing it to be perfect, must ever goats, oxen, and lambs refuse almost be incompetent to solve physiological all the solaneæ ; and the poisons are problems, to which, indeed, it must food to many, the rabbit devouring always afford indispensable aid, withbelladona, the goat hemlock, and the out hope of doing more. horse aconite. The dog will feed on Vital processes depend on chemibread, or biscuit, which his ancestor cal processes, but are not chemical, the wolf would starve rather than and cannot, therefore, be explained touch. The cat, although preferring by Chemistry. There is something animal food, will eat bread and milk, special in vital phenomena which which the tiger will not look at. necessarily transcends chemical in
We have brought these facts forward vestigation. We need not pretend to for the sake of giving distinct relief settle what vitality is, or on what the to the importance which must inevit- speciality of its phenomena ultimately ably belong to physiological consider- rests, to be assured that it is someations in every question of Food ; and thing quite unlike what goes on in to indicate the necessity of fixing our our laboratories, and demands other attention on the organism to be tests than those furnished by Chenourished, rather than on the chemi- mistry. The philosophic poet warns cal composition of the substances which nourish it. When we are “ From higher judgment-seats make no building a bridge, or making a appeal machine, we can accurately guide
To lower ;” ourselves by estimates of the strength and such appeal, from higher to of the wood and iron, because these lower, is the appeal of Physiology to substances do not lose their properties Chemistry, No analysis of a nerve under new arrangements; but in will ever throw light on Sensibility; building the mysterious fabric of the
no arrangement of chemical formula body, we have little or no guidance will explain the form and properties from our estimates of the properties of a cell. You may take a mechanism of substances out of the body, be- to pieces, and explain by physical cause the body itself is an important laws the action and interaction of factor in the sum, acting on the sub- each wheel and chain ; but you canstances as well as acted on by them, not take a tissue to pieces, and from annulling or exalting their properties the elements deduce its properties. in a way quite peculiar to itself. If an overwhelming illustration of And it is because this has been over- this obvious truth be needed, we may looked, or not sufficiently estimated, find it in the ovum of an animal :
* Mulder: Versuch einer Physiol. Chemie. LEHMANN : Lehrbuch, d. Physiol. Chemie, 2d edit.
here is a microscopic sphere, composed canon intelligible, and at the same of substances well known to chemists, tiine to uproot a widespread fallacy, which contains potentially an animal, Few errors have gained more general and will reproduce not only the form, acceptance than that which declares features, stature, and specific attri- the Family to be the perfect type of butes of the parents, but also many of the State, and which would regulate their acquired habits, tendencies, and polity by domestic rules. A paternal tricks ; has Chemistry, in the whole government, in which the monarch is extent of its domain, anything analo- the head of the family; and a social gous to this ? Can Chemistry furnish government, in which all men are us even with an approach to an ex- united as brothers, are the two ideals planation of it ! Chemical analysis of absolutists and socialists, who are inay conduct us to the threshold of pitiless in scorn of all other political Lite, but at the threshold all its guid- schemes. When we see how a wellance ceases. There, a new order of com- conducted household is harmoniously plications intervenes, a new series of governed, each member fulfilling his laws has to be elicited. Chemistry proper office, and each assisting all; confesses its inability to construct when we see how the farmer adminiorganic substances, or even to say sters his affairs without any one to how they are constructed ; it can, at question his absolute will; the idea present, only say of what they are of so managing a nation naturally constructed. This being so, it is suggests itself, for What is a nation clear that every atteinpt to explain but an extension of the family ? ask chemically the nutritive value of any the theorists. I answer, the Family aliment, by an enumeration of its is specifically different from the Na
, constituents, must belong to what tion : it is no type of the State, beBerzelius admirably styles “the phy- cause, not to mention other points, it siology of probabilities.
has the bond of personal affection, There is one cardinal rule which and the bond of personal interest, can never be violated with impunity, which two puissant influences can and which is, nevertheless, perpetu- never operate to anything like the ally violated in our gropings towards same extent on the State. The father the light. It is this : Never attempt dearly loves his children, and his desto solve the problems of one science by potism may be absolute because it is the order of conceptions peculiar to truly paternal, his tender vigilance and another. There is an order of con- forgiving love will soften all the harshceptions peculiar to Physics, another ness of absolute rule. But no philpeculiar to Chemistry, a third pecu- anthropist will be romantic enough fiar to Physiology, a fourth peculiar to to expect that king or kaiser can by Psychology, a fifth peculiar to Social any possibility feel this affection for Science. While all these sciences are his subjects ; and thus one essential intimately related, each has its sphere element of the family disappears. of independence which must be re- Again, the father's personal interest spected. Thus Chemistry presup- is bound up with his administration poses Physics, and Physiology pre. (as the farmer's is), and every false supposes Chemistry; but no physical step he makes will be made feelingly laws will explain chemical pheno- evident to him. But the sovereign's mena, no chemical laws will explain personal interest is not in any such vital phenomena; nor,conversely, will manner directly bound up with the Chemistry solve physical problems, goodness of his administration ; if he nor Physiology solve chemical pro- can keep secure upon his throne, if blems. In every vital process physi- neither revolutions nor assassins are cal and chemical laws are implied, provoked, it can make little difference and the knowledge of these becomes to his welfare if the streets are filled indispensable ; but over and above with lamentations, and the battlethese laws, there are the specific laws field with corpses. And even supof Life which cannot be deduced from posing him to be tender-hearted and Physics and Chemistry.
conscientious, really desirous of the Ăn illustration drawn from social good of his subjects, yet his own perscience may serve to render this sonal interest is not so directly and
obviously bound up with theirs as the same individual; and as every that of the father's with his house- variation in composition necessarily hold. Thus, on the supposition that affects the properties of each subthe despot is the best and wisest stance, it is impossible that such acof men, and his subjects are really tions can be reduced to those exact desirous of universal brotherhood quantitative formulæ on which Che(two tremendous assumptions always mistry, is founded. Chloride of soquietly made), the Family could offer dium is the same substance, having no proper type of the State, because precisely the same composition and the two most puissant elements in the properties, whether taken from the Family must be wanting in the State. sea, from the earth, from the plant, The application of the canon just laid or manufactured in the laboratory. down is easily seen : while, on the But nerve-tissue is never precisely one hand, the Family must neces- the same in two men; the blood of sarily enter into the State, which is no two men is precisely alike; the in truth an aggregation of families, milk of no two women is identical in it can never furnish the typical laws composition--they all vary (within for the State, because the actions of certain limits), and sometimes the individual men cannot be the standard variation is considerable. It is on for the actions of masses, and the mere this, as I have elsewhere maintained, aggregation of families brings about that depends what we call the diffesuch a complication of interests, pas- rence of“temperament,” which makes sions, and opinions, that a totally one twin so unlike his brother, and new set of relations is evolved. Thus makes the great variety of the huprecisely as Polity presupposes Domesticity, but is not embraced by We have now done with the geneit, precisely as the State is dependent ralities which it was needful to exon the Family, and is, nevertheless, plain before approaching the quesbelonging to a higher jurisdiction, só tion of Food. If the reader's assent does Physiology presuppose Chemis- has been gained, he will see that try, but is not included in it, cannot from the radical incompetence of be regulated by its laws. Domestic Chemistry to settle any true physiolife furnishes the basis for political logical question whatever, all the life, as chemical actions furnish the laborious efforts of later years have basis for vital actions.
been barren, or nearly so,
as regards Whatever the future progress of the important subject of Food, beChemistry may effect in the way of cause they have been only chemical simplifying physiological problems reasonings on Physiology. Plausible (and no one doubts that it must and brilliant as some of the theories greatly aid us), there is one radical have been, they are all at fault when distinction which must ever keep the reduced to practice. They have two sciences separate. It is this : gained general acceptance, because Chemical laws are quantitative, be- of the simplicity with which they cause chemical actions are definite seemed to solve abstruse problems; combinations ; whereas physiological and the human mind is so eager to laws can never become quantitative, have explanations, that any logical but only qualitative, because vital plausibility is sure to captivate it. substances are indefinite in composi- Of all current hypotheses on this tion; that is to say, while chemical subject, none claims a closer scrusubstances are formed by combina- tiny than that which_Liebig has tions of unvarying quantities, never made familiar to all Europe, and more, never less, so much acid to so which, winged by the two qualities much base always forming the same of simplicity and plausibility, has salt, so many atoms of one substance been carried into the lecture-room always uniting with so many of an- and study, where it continues to other to forin a third ; the substances hold its place, in spite of the growing on which vital actions specially de- conviction that it is untenable. Liepend are never precisely and accu- big divides Food into two classes. rately definite ; they vary in different The first is Plastic, or tissue-making, individuals, and at different ages of and comprises the organic substances