The chemical and physiological balance of organic nature; an essay

Front matter

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OF ABERDEEN.

Preface

The Essay which my colleague, M. Boussingault, and I now submit to the public, comprises, in brief terms, an exposition of the grand features in the life of plants and animals considered in a chemical point of view.

It presents a variety of new views, calculated to supply general physiology, medicine, and agriculture, with grounds upon which the study of the chemical phenomena that take place in organised beings may be advantageously pursued.

We feel intimately persuaded that the considerations embraced in this Essay may henceforth be made to bear upon many of the most important questions of public economy. — Not that we have given such developement to our principles as makes them always obviously

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applicable to matters of detail, — time alone will admit of our doing this ; but we apprehend that our views, generally speaking, are so stated, as to shew conclusions interesting to the legislator and public economist in connexion with agriculture in general, and in particular with the growth of corn, and of sugar, the feeding of cattle, and, above all, with that question, — of such vital importance, — the maintenance of the labouring classes of mankind.

With regard to the shape in which this little work is published, it will be enough to state that after having settled our views upon the various questions it embraces, one of us took upon himself the task of developing these view’s in his Course at the Ecole de Médecine, and of giving a summary of them in a concluding discourse, which is here reported verbatim.

We have, however, added, in the form of an Appendix, a series of documents comprising a definite statement of the principal facts and most important laws.

It is our purpose, at a future time, to publish the whole of the details which the subject

PREFACE.

involves but we trust that we shall be excused for anticipating this intention by the present sketch. The summary in the hands of the reader, in fact, presents him with a host of questions, which, taken isolatedly, would appear altogether unimportant, but which, in their connexion with the general theory espoused, acquire a character of the very highest interest. May we but inspire him with a taste for these inquiries — with a desire to engage in studies that offer so vast a scope for activity of every kind, and that teem with conclusions of the last consequence to mankind !

J. Dumas.

* This has just been done by M. Boussingault, in his work, entitled, “Rural Economy/’ — English Editor .

TO THE

THIRD EDITION.

In publishing a Third Edition of our little work, we lay aside the repugnance that is naturally felt in speaking of our own views, assured that these have now obtained all but universal assent.

Transferred to the pages of many scientific and literary journals, translated into English, German, Spanish, and Italian, this Discourse has disseminated views that will, doubtless, exert a powerful influence on the progress of agriculture and the general economic management of the soil.

Several of our details have, almost as a matter of course, found opponents ; but hitherto we have not had to change our opinions upon a single point of any importance, although ready to do so, should careful experiments and pre-

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cise facts at any time make change necessary. We take this opportunity of saying so much, not haying deemed it requisite to come forward as defenders upon every occasion in which our opinions have been called in question.

In the same way, if we have been silent with regard to the many claims of priority which have been preferred, it is because we believed that every one might readily satisfy himself that our views are founded on a mass of evidence derived from our own personal experience, or from that of a small circle of friends, who have long held the same opinions as ourselves. Abundant proof of this will be found in the documents appended to this Edition.

Nevertheless, the dissent, the discussion, the attacks, to which the publication of this Essay has given rise, make it imperative on the subscriber of this notice to take on himself his share of responsibility for the views which it contains, and which additional experience, time, and reflection, seem but to strengthen.

Boussingault.

Paris , January 10, 1844.

Contents

PAGE

Preface . v

— — to 3d Edition ix

I

Vegetables, animals, man, contain matter in their composition. Whence comes it? What part does it play in their tissues and in the fluids which bathe them? What becomes of it when death breaks the chain by which its various parts and forms were so closely conjoined?

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Such are the questions which we approached with so much diffidence at first, inasmuch as to answer them might have been beyond the powers of modern chemistry ; hut, by and by, with greater confidence, when we felt, by the silent and secret accord of our minds, that our footing was sure, and as we saw that the wished-for goal was gradually approached in spite of every obstacle. If, from this labour, at which you have been spectators, — in which, I should rather say, you have lent your aid, — if from this scientific effort some general views have arisen, some simple and comprehensive formulæ have appeared, I feel that I ought to make myself the historian of these : — but allow me the pleasure of adding that they also belong to you, that they belong to our school, the spirit of which has, of late, been unfolding itself upon this new ground. It is the zeal, indeed, with which you have followed me in this career that has given rne the strength to pursue it ; it is the lively interest you have taken that has sustained me, your curiosity which has awakened mine, your confidence which has made me see, — which assures me at this moment, that we are in the path of truth.

These words will bring to your minds with what amazement we discovered together, that of all the elements of modern chemistry, organic nature made use of but three or four ;

that of those vegetable and animal substances which are now multiplied almost to infinity, general physiology requires no more than some ten or twelve species ; and that all the phenomena of life, so complex in appearance, may be referred in their essence to a single general formula, so simple, that in a few words every thing seems stated, every thing having been recalled to mind, every thing foreseen.

Have we not, in fact, found, by a multitude of results, that an animal, in a chemical point of view, constitutes a true apparatus of combustion, by which carbonaceous matters, burnt incessantly, are returned to the atmosphere in the shape of carbonic acid ; in which hydrogen, burnt incessantly, is returned as water ; whence, in fine, free azote is ceaselessly exhaled in the breath, and, in the state of oxide of ammonium, is thrown off in the urine ?

From the animal kingdom, therefore, as a whole, carbonic acid, watery vapour, and azote or oxide of ammonium, are continually escaping,— simple substances, and few in number, the formation of which is intimately connected with the history of the atmosphere itself.

Have we not, on the other hand, found that vegetables, in their natural and healthy state, decompose carbonic acid incessantly, fixing the carbon, and setting free the oxygen ; that they decompose water, seizing on its hydrogen, and

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disengaging its oxygen as before ; lastly, that they either abstract azote directly from the air, or take it indirectly from oxide of ammonium, or nitric acid ; thus acting, in every particular, inversely or in opposition to animals ? If the animal kingdom constitute an immense apparatus of combustion, the vegetable kingdom, in its turn, constitutes an immense apparatus of reduction, where carbonic acid decompounded leaves its carbon, water its hydrogen, and oxide of ammonium and nitric acid their ammonium or their azote.

If animals incessantly produce carbonic acid, water, azote, and oxide of ammonium, vegetables consequently consume, without cease, oxide of ammonium, azote, water, and carbonic acid. What the one gives to the atmosphere, that the other takes from it ; so that, surveying these facts from the loftiest point of view, and in connexion with the physics of the globe, it would be imperative on us to say that, in so far as their truly organic elements are concerned, plants and animals are the offspring of the air ; that they are but condensed or consolidated air ; and that, to form a true and accurate idea of the constitution of the atmosphere at the epochs which preceded the birth of organised beings, it would be necessary to restore to it, by calculation, the whole of the carbonic acid and azote, the elements of which were appropriated by vegetables and animals when they appeared.

Vegetables and animals, therefore, come from the atmosphere, and return to it again ; they are true dependants of the air.

Vegetables, then, assume from the atmosphere the elements which animals exhale into it ; viz. carbon, hydrogen, and azote, or rather carbonic acid, water, and ammonia.

But how do animals procure the elements which they give to the atmosphere ? Let us inquire particularly into this point. Now it is impossible to contemplate, without admiration, the sublime simplicity of the laws of nature here, as every where ! Animals always derive their elements primarily from vegetables.

We have found, in fact, by results beyond the reach of question, that animals do not create any of the truly organic substances, but that they consume or destroy them ; that vegetables, on the contrary, habitually create these substances, and that they destroy but few, and this only for particular and determinate ends.

It is, in the vegetable kingdom therefore, that the great elaboratory of organic life is found ; it is there that both vegetable and animal substances are compounded: and they are all alike formed at the cost of the atmosphere.

From vegetables these substances pass readyformed into the bodies of herbivorous animals,

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which destroy one portion of them, and store up another in their tissues.

From herbivorous animals they pass readyformed into the bodies of carnivorous animals, which destroy or lay them up, according to their wants.

Finally, during the life of these animals, or after their death, the organic substances in question return to the atmosphere from whence they originally came, in proportion as they are destroyed.

Thus is the mysterious circle of organic life upon the surface of the globe completed and maintained ! The air contains or engenders the oxidised substances required, — carbonic acid, water, nitric acid, and ammonia. Vegetables, true-reducing apparatus, seize upon the radicals of these, carbon, hydrogen, azote, ammonium ; and with them, they fashion all the variety of organic or organisable matters which they supply to animals. Animals, again, true apparatuses of combustion, reproduce from them carbonic acid, water, oxide of ammonium, and azotic or nitric acid, which return to the air to reproduce the same phenomena to the end of time.

And if, to this picture, already so striking by its simplicity and grandeur, we add the indubitable part performed by the solar light, which is alone possessed of power to bring into play this immense, this unparalleled apparatus, constituted by the vegetable kingdom, in which the oxidized products of the atmosphere are subjected to reduction, it is impossible not to be struck wTith the import of these words of Lavoisier : “ Organisation, sensation, voluntary motion, life, only exist on the surface of the earth and in places exposed to light. It might be said, indeed, that the fable of Prometheus was the expression of a philosophical truth, which had not escaped the penetration of the ancients. Without light, nature were without life and without soul : a beneficent God in shedding light over creation strewed the surface of the earth with organisation, with sensation, and with thought !”

These words are as true as they are eloquent. If sensation and thought, if the noblest faculties of the soul and the understanding require a material vesture for their manifestation, vegetables are the labourers charged with the task of building it up, and from elements which they derive from the air, and elaborate under the influence of the light which the sun, its inexhaustible fountain, pours in ceaseless floods upon the earth.

And, as if all in these grand phenomena were destined to be associated with causes which should appear the most remote, we may here observe upon the sources whence the

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oxide of ammonium and azotic acid, from which vegetables derive a portion of their food, are themselves derived. They are, in fact, produced upon the grand scale by the action of those magnificent electric sparks that dart from the storm-cloud, and, furrowing vast fields of air, engender in their course the nitrate of ammonia, which analysis discovers in the thunder-shower.

As it is from the mouths of volcanoes, then, whose convulsions so often make the crust of our globe to tremble, that the principal food of plants, carbonic acid, is incessantly poured out ; so is it from the atmosphere on fire with lightnings, from the bosom of the tempest, that the second and scarcely less indispensable aliment of plants, nitrate of ammonia, is showered down for their behoof.

Might it not be said, that we have here a remembrancer of that chaos mentioned in the Bible, of those periods of tumult and disorder which preceded the appearance of order and organisation upon the earth ?

For, scarcely are carbonic acid and nitrate of ammonia formed, than a calmer, though not less energetic force begins to act upon them for new purposes : this force is light. By the agency of light, carbonic acid yields up its carbon, water its hydrogen, nitrate of ammonia its nitrogen. These elements combine.

organic matters are formed, and the earth is clothed with verdure.

It is, in fact, from absorbing incessantly a true force, the light and heat of the sun, that vegetables perform their functions, and produce the vast quantities of organised or organic matter which are the destined food of the animal creation.

And then, if we add that on their side animals engender heat and elicit force in consuming that which vegetables have produced and slowly accumulated, would it not seem that the ultimate intent of all these phenomena, that their most general or comprehensive formula was laid open to our view ?

The atmosphere presents itself to us as including the primary materials of all organisation. Volcanoes and thunder-storms meet us as the laboratories in which are compounded the carbonic acid and nitrate of ammonia which life requires for its manifestation and extension.

Light arrives, and with the concurrence of carbonic acid and nitrate of ammonia, the vegetable world, the grand producer of organic matter, is developed. Plants farther absorb the chemical force which reaches them from the sun and enables them to decompose carbonic acid, water, and ammonia ; plants are embodiments of a reducing power, of greater virtue than any

OF ORGANIC NATURE.

other that is known, for no other will decompose carbonic acid in the cold.

Then come animals, consumers of matter, and producers of heat and of force, true instruments of combustion. It is in them, unquestionably, that organised matter acquires what may be called its highest expression. But it is not without detriment to itself that it becomes the instrument of sensation and of thought. In this new capacity organised matter is burnt; and in giving out the heat, or electricity which constitutes and is a measure of our force, it is destroyed and returned to the atmosphere from whence it had originally come.

The atmosphere, therefore, is the mysterious link that connects the animal with the vegetable, the vegetable with the animal kingdom.

Vegetables absorb caloric, and store up the matter which they have had the power to fashion ;

Animals, again, through which, it may be said, that organic matter merely passes, burn or consume it, to produce by its means the heat and various forces which their motions turn to profit.

Allow me, here, borrowing a simile from modern science, of grandeur somewhat commensurate with these grand phenomena, to liken the vegetable world of the present age, the true storehouse whence animal life is fed, to that other magazine of carbon which we possess in our primeval beds of coal, and which, burnt under the genius of Papin and of Watt, produces carbonic acid, water, heat, motion, — we might almost add, life and intelligence.

In our eyes, therefore, the vegetable world constitutes an immense magazine of combustible matter, destined to be consumed by the animal world, and in which this last finds the source of the heat and locomotive powers which it turns to account.

A common link between the two organic kingdoms, then, — the atmosphere ; four elements in vegetables and in animals — carbon, hydrogen, azote, and oxygen ; a very limited number of forms under which vegetables lay these up, under which animals consume them ; a few laws of great simplicity, which their enchainment simplifies still more : such is the picture of organic chemistry in the abstract, which results from our studies of the present session.

You, doubtless, felt as I did myself, that, before finally separating, it would be well for us to fall back upon ourselves, as it were, to make sure of our data, and to contrast and review our opinions, in which are involved the explanation and developement of the grand principles which we have announced ; finally, that it would be advantageous to you in your future

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studies, to have, in writing, and in precise terms, the expression of views which have been engendered in part under the stimulus of your regards, and therefore presented with the hesitation which so frequently accompanies the first cast of our thoughts.

II

Inasmuch as all the phenomena of life are carried on upon substances having for their bases carbon, hydrogen, nitrogen, and oxygen ; inasmuch as these substances pass from the animal to the vegetable kingdom, through in* termediate forms — carbonic acid, water, and oxide of ammonium ; since, in fine, the air is the source whence the vegetable world is nourished, is the reservoir within whose bosom the animal world is annihilated, we are naturally led to study these different bodies from the particular point of view of general physiology.

Composition of Water (1 ). — Water is incessantly formed and decomposed in the bodies of animals and vegetables. With a view to the due appreciation of what is to follow, let us inquire into its composition. Direct experiments,— the combustion of hydrogen in oxygen gas, — in which I have produced more than a quart of artificial water, render it extremely probable that water is composed by weight, of

1 part Hydrogen, and 8 parts Oxygen, and that these simple and round numbers express the prime relations in which these two elements combine to constitute water.

As substances are always represented in the eyes of the chemist by atoms or molecules, as he always seeks to connect in thought, with every substance, the weight of its atom, the simplicity of the relation just stated is not without importance. Each atom of water, in fact, being a compound of one atom of hydrogen and one atom of oxygen, we arrive at those simple numbers, which are not readily forgotten. An atom of hydrogen weighs 1, an atom of oxygen weighs 8, and an atom, or molecule of water, weighs 9.

Composition of Carbonic Acid (2). — Carbonic acid is produced incessantly by animals, and decomposed incessantly by plants ; its composition, therefore, merits especial attention on our part.

Now carbonic acid, like water, is represented by the most simple numbers.

Experiments in which the diamond was burnt directly, and converted into carbonic acid, have satisfied me that this acid is formed by the combination of 6 parts, by weight, of carbon, with 16 parts, by weight, of oxygen.

We are, therefore, led to represent carbonic acid as formed of 1 atom of carbon weighing 6, and two atoms of oxygen weighing 16,

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which together constitute 1 atom of carbonic acid weighing 22.

Composition of Ammonia (3). — Finally, ammonia would appear, in its turn, to be formed, in round numbers, of 3 parts of hydrogen and 14 of azote, which may be represented by 3 atoms of hydrogen weighing 3, and 1 atom of azote weighing 14.

Thus, as if to shew her infinite resources, Nature does not bring into play, in connexion with organisation, more than a very small number of elements, combined in the simplest relations.

The whole atomic system of the physiologist, in fact, revolves upon these four numbers, 1, 6,7,8:

1 is the atom of hydrogen,

6 is that of carbon,

7, or twice 7=14, is that of azote, and 8 is that of oxygen.

Let him always attach these numbers to these names; because to the chemist no such things as abstract hydrogen, carbon, azote, or oxygen, exist. They are always true entities which he has in view ; it is of their atoms that he invariably speaks, and for him the word hydrogen signifies an atom which weighs 1, the word carbon an atom which weighs 6, and the word oxygen an atom which weighs 8.

Composition of the Air { 4). — Has the atmosphere which plays so important a part in organic nature, as simple a constitution as water, carbonic acid, and ammonia? Such is the question which M. Boussingault and I have lately studied attentively. And we have found, in conformity with the opinions of the majority of chemists, and in opposition to the views of of Dr. Prout, to whom chemistry is indebted for so many ingenious inquiries, that air is a mixture, a true mixture.

The air of the atmosphere contains, by weight, 2300 of oxygen to 7700 of azote ; by volume, 208 of the former to 792 of the latter.

The air contains, in addition, from to T^-OTths,by volume of carbonic acid, whether it be taken in the midst of a great city such as Paris, or in the country. (5) In general it contains about Tôéôô^hs °f carbonic acid.

The air, moreover, contains an almost inappreciable quantity of the carburetted hydrogen gas, which is incessantly evolved by stagnant waters and marshes. (6)

We do not here speak of the watery vapour, the quantity of which varies so much at different times, nor yet of the oxide of ammonium and nitric acid, which can only exist momentarily in the atmosphere, by reason of their great solubility in water.

The air of the atmosphere, therefore, is a mixture of oxygen, nitrogen or azote, carbonic acid, and carburetted hydrogen or marsh-gas.

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The quantity of carbonic acid in the atmosphere varies, and that even considerably, inasmuch as the difference extends from -ro-ooo^18 to T()fôô^s* Might not this fact be cited as a proof that plants abstract carbonic acid from the air, whilst animals exhale it? is it not an assurance that the equilibrium in the elements of the air is rightly ascribed to the inverse actions of animals and of vegetables upon it ?

It is long, indeed, since it was observed, that animals rob the air of its oxygen, and exhale into it carbonic acid ; and that plants, in their turn, decompose this carbonic acid, fixing its carbon, and restoring its oxygen to the air.

As animals go on breathing incessantly, and as plants only respire under the influence of the solar light ; as in winter, the earth is stripped and naked, whilst in summer it is clothed with verdure ; it was believed that the air ought to bear witness in its constitution to these varying states or influences. The carbonic acid, it was imagined, must increase in the night and diminish in the day ; the oxygen, on the contrary, diminish in the night and increase in the day.

The carbonic acid and the oxygen, it was also conceived, must follow the course of the seasons, augmenting inversely in one, falling off inversely in the other. (7)

All this is true, undoubtedly, and perfectly

c sensible in regard to small portions of air confined under a bell-glass ; but in the mass of the atmosphere all local and temporary differences are lost and confounded. A long succession of ages would be requisite to bring into play and render manifest any preponderance in either of the two realms of nature, with reference to the composition of the atmosphere. We are, therefore, far — very far from experiencing those daily or annual variations which philosophers and the vulgar were at one time alike disposed to regard as equally easy to observe and to foresee. (8)

With regard to the oxygen, calculation shews that, even in exaggerating all the data, not less than 800,000 years must elapse before the animals living on the surface of the earth could consume it entirely.

If it be supposed, therefore, that an accurate analysis of the air was made in the year 1800; and that, through the whole of the succeeding century, plants had ceased from their functions over the entire surface of the earth, all the animals, nèvertheless, being conceived to go on, living and breathing as usual, an analysis undertaken in 1900 would not shew the oxygen of the air diminished to any greater extent than g~ïï1ïïïïth part of its weight, a quantity which is altogether inappreciable to the most delicate means of investigation we

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possess at the present day, and which, very certainly, would have no influence on the life of animals.

Nevertheless we do not deceive ourselves as to the fact : the oxygen of the air is consumed by animals, which convert it into water and carbonic acid ; and it is restored by vegetables, which decompose these two substances.

But nature has so arranged matters that the magazine of the atmosphere, in reference to its consumption by animals, is such, that the necessity for the intervention of vegetables for its purification could only become apparent after the lapse of centuries.

The atmosphere which surrounds us weighs as much as 581,000 cubes of copper, one kilometre in the side ; its oxygen alone weighs as much as 134,000 of these cubes. Now, supposing the earth to be peopled by 1,000,000,000 of men, and its animal denizens to be equivalent to 3,000,000,000 of men, it may be shewn that these together do not consume a weight of oxygen equal to 15 or 16 cubical kilometres of copper in the course of a year, whilst the air, as we have seen, contains 134,000 of such kilometres.

It would require no less a period than 10,000 years before all the men on the face of the globe could produce any effect that should be sensible to Volta’s eudiometer, even supposing vegetable life to be extinct daring the whole of this time.

With regard to the question of permanence in the composition of the atmosphere, therefore, we may say, with a perfect assurance of accuracy, that the proportion of oxygen which it contains is secured for a long succession of ages, even supposing the influence of the vegetable world to be nil ; and that plants, nevertheless, go on incessantly restoring to it oxygen in quantity, at least equal, and perhaps even superior, to that which it loses ; for vegetables live at the expense of the carbonic acid that is emitted by volcanoes, as well as of that which is exhaled by animals.

It is not, therefore, as purifiers of the air, that plants are so immediately and especially necessary to animals ; it is rather as supplying them, and that incessantly, with organic matter ready prepared for assimilation, w hich they may burn or otherwise consume to their advantage.

The service which vegetables render us in purifying the air we breathe is necessary, without doubt, but it is so remote that our gratitude is little. There is another service, so immediate, so intimate, that did it fail for but a single year, the earth would be depopulated : it is that which these same vegetables confer in preparing food for us, and for the whole animal creation. It is here especially that the

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connexion of the two kingdoms of nature is remarkable. Annihilate vegetation, and forthwith animals perish of hunger; the entire realm of organisation must necessarily disappear with that of vegetation.

Yet we have said that the carbonic acid of the atmosphere varies from t0 tôo^ôô'^1s

of its bulk. These variations are easy to observe, and they occur very frequently. May not this be a phenomenon proclaiming the influence of animals which introduce this acid into the air, and that of plants which abstract it ?

No ; you are aware of the fact, that the phenomenon in question is simply meteorological. It is with carbonic acid as with watery vapour, which is formed at the surface of the ocean to be condensed elsewhere, to fall back as rain or dew, and to be raised again in the form of vapour.

This water, which is condensed and falls, dissolves and precipitates the carbonic acid ; this water which evaporates, raises and abandons the same gas to the air.

It would, consequently, be of great interest, meteorologically, to contrast the variations of the hygrometer with those of the seasons, and the state of the heavens with variations in the quantity of carbonic acid contained in the air ; but hitherto all tends to prove that the rapid variations observed constitute simple meteorological incidents, and by no means, as was once supposed, physiological incidents, which, isolatedly considered, would very certainly produce variations vastly more slow than those that are actually noted, whether in cities or the country.