( Originally Published 1913 )
IT may be taken as evidence of the erroneous views current among scientific men on the true nature of science as respects Classification, that a distinct body of doctrine should claim for itself a distinct existence in the shape of a " Science of Organic Chemistry." Against this supposed science, Comte energetically protests as a source of inevitable confusion, and as a consequence of the absence of that Philosophy of Science which he has endeavoured to elaborate.
Open Dr. Gregory's admirable Handbook of Organic Chemistry the latest published,and read this definition : " Organic Chemistry is so called because it treats of the substances which form the structure of organized beings and of their products, whether animal or vegetable." Now, although it is not possible, I believe, to draw a line of demarcation between the inorganic and organic worlds, although the differences we observe are not essential, but phenomenal, nevertheless positive philosophers, who only study phenomena, recognise a marked difference between the phenomena of organized and those of inorganized substances, a difference which necessitates a corresponding difference in Classification; and as the phenomena of organized matter are regulated by special laws not applicable to inorganized matter, we ought to isolate them from the phenoméa of inorganized matter. Comte, therefore, properly objects to physiological phenomena being treated as simple chemical phenomena ; he objects to the Chemist undertaking to solve problems which require the cooperation of the Physiologist ; he objects to a science which, while it has physiology for its subject matter, attempts to dispense with physiological Method. The very phrase, Chemistry of organized bodies, implies the presence of an element not within the competence of Chemistry, except upon a vicious extension of the term. Chemistry does not concern itself with the phenomena of Life ; yet those phenomena are necessary to organized bodies !
In protesting against making Organic Chemistry a separate science, he must not be understood to underrate the importance of inquiries into the chemistry of organized bodies. His meaning is, that you might as well constitute a science of Animal Mechanics from the specification of all the mechanical phenomena observable in animals, as a science of Organic Chemistry from a specification of the chemical phenomena noticeable in organic bodies.
Physiology is subordinate to Chemistry ; the greater complexity of its phenomena embraces chemical laws, and some other laws peculiar to itself. That the physiologist could not create his science without the aid of Chemistry, lies in the very nature of Physiology ; but the chemist can and does create Chemistry without the aid of the physiologist. Therefore positive philosophy insists upon a division of this said Organic Chemistry into two different parts; 1st. That which relates to Chemistry, properly so called. 2nd. That which relates to Physiology. Few minds familiar with the importance of Method will fail to appreciate the necessity of this division.
The general principle upon which this division must be founded, Comte says, resides "in the essential separation of the condition of Death from that of Life, or, what comes to nearly the same thing, the stability and instability of the proposed combinations subject to the influence of ordinary agents. Among the various compounds indistinctly united under the. term organic, some owe their existence to the vital movement, are subject to continual variations, and almost always constitute simple union : these cannot belong to Chemistry, but to Biology, static or dynamic, according as we study them in their fixed state, or in the vital succession of their regular changes : blood, lymph, fat, &c., are of this class. The others, on the contrary, forming the proximate principles of these, are substances essentially dead, susceptible of remarkable permanence, and presenting all the characters of true combinations, independent of life : these, the organic acids, alcohol, albumen, urea, &c., belong to the domain of Chemistry, for they are the same as inorganic substances."
How, then, is the Chemist to distinguish between what belongs to his domain and what to the domain of Biology ? By a very simple rule. He has only to examine whether the proposed problem can be solved by the application of chemical principles alone, without the aid of any consideration of physiological action whatever. As soon as any of the phenomena of Life manifest themselves, he is warned of the presence of more complex agencies than are " dreamt of in his philosophy."
It is well known that although we can create certain organic compounds, we can only do so by the degradation of some previously existing organic substance. It is in vain that we analyze organic matters and ascertain their elements; we cannot put those elements together again, as we can with inorganic substances. There lies a mystery of synthesis to be touched on hereafter.
And this leads me to some considerations which may not be out of place, as an introduction to the next section.
Is there, except as a scientific artifice, any distinction between Inorganic and Organic bodies? No. The same elements are common to both ; the differences in the phenomena are owing to differences in the arranbement of these elements ; just as starch, wood, and sugar are different in their properties, though composed of the same elements.
Whether we suppose the unknown Forces which manifest themselves in phenomena to be many, or one, taking many directions whether we suppose the so-called elementary atoms to be distinct elements, or one element, the conclusion is not ' affected that, Between inorganic and organic bodies one principal distinction lies in the latter being combinations of more complex orders. Thus, a particle of salt is composed of a group of two atoms, while a particle of olive oil is composed of several hundreds of atoms. From the dawn of organic life upwards, we perceive an ascending complexity, owing, primarily, I believe, to the greater multiples of the elementary equivalents. Thus, if a particle of salt contains only two atoms, these two atoms only attract each other in one direction; but in a particle of sugar, which consists of thirty-six atoms, the attraction is acting in thirty-six different directions. " Without adding," says Liebig, " or withdrawing any element, we may conceive the thirty-six simple atoms, of which the atom of sugar consists, to be arranged in a thousand different ways ; with every alteration in the position of any single atom of the thirty-six, the compound atom ceases to be an atom of sugar, since the properties belonging to it change with every alteration in the arrangement of the constituent atoms." (Letters on Chemistry.)
The four elements, named organogens, oxygen, hydrogen, carbon, and nitrogen, are infinite in their modes of combination. Lead and oxygen combine in two proportions only, viz., the protoxide Pb 0, and the peroxide Pb 02, and these unite to form a third combination, red lead. But the combinations of the organogens are innumerable, and differ, not only in relative but in absolute quantities (Mulder: Physiologische Chemie.) and it is from the infinite variety of these combinations these directions of force, that the variety of organic phenomena proceed.
To make intelligible by an illustration this effect of different arrangement : When iron is in mass it has but a slight tendency to become oxidized; but the same mass of iron, if minutely divided, cannot be brought into contact even with atmospheric air at a low temperature, without becoming red hot, and at the same time becoming converted into an oxide. Cobalt, nickel, and uranium possess the same qualities (Mulder). What is the explanation of this curious fact which, by the way, is at the service of homoeopathists as an argument for triturated medicines ? Not that the particles of iron acquire a new force by division ; but that these molecules, when accumulated into a mass, are prevented from acting in that direction, and their force is what we call "latent."
We come, then, to the conclusion that, between the inorganic and the organic there is mainly a difference of combination, an increasing complexity in the lines of direction of force. This is the foundation stone of the dynamical theory. Once suppose a new force created, and the mechanical theory will support the pretensions of metaphysics ; development will give place to incessant creation, and the metaphysical entities named Vital Principles will reign supreme. For, observe, the marked phenomenal difference between organized and inorganized matter naturally strikes men as arising from essential differences. " There was a time when men could not account for the origin of the lime of the bones, the phosphoric acid in them and in the brain, the iron in the blood, and the alkalies in plants ; and we now find it inconceivable that this ignorance should have been regarded as a proof that the animal or vegetable organism possessed the power of creating iron, phosphorus, lime, and potash, by virtue of its inherent vital forces, out of food containing none of these substances.
This convenient explanation naturally put an end to the inquiry as to their real origin, and arrested true investigation." (Liebig.)
Unless we accept some such metaphysical explanation, how are we to understand, if inorganic and organic are essentially different the ordinary processes of nutrition and growth ? A plant takes from earth, air, and water certain gases, which it converts into cellular tissue, and thence into woody tissue, and so on—i. e., creates organic matter from inorganic matter; plays the part of a God by virtue of its " inherent vital forces !" Whereas, on the dynamic theory, although the mystery of Life remains as inaccessible as ever, the Methods of Nature are at least conceived to be consistent and homogeneous.
Many prejudices will be shocked by this identification of the organic with the inorganic; but Truth is always consistent with itself, and on no other conception can the whole of the phenomena be made consistent. This denial of any essential distinction between the organic and inorganic is confirmed by Mulder, the greatest philosophic chemist of the day ; and to the first ninety-five pages of his Physiologische Chemie I refer the reader.* Indeed, one of the most indisputable truths which the study of Nature elicits is the impossibility of drawing definite lines of demarcation. Every one knows how the animal and vegetable kingdoms are inextricably interlaced at their boundaries ; and when men find the articulations of the Gallionella ferruyinea one of the Infusoria discovered by Ehrenberg composed almost entirely of oxide of iron, they are puzzled where to draw the line between the mineral and the animal. Müller, indeed, insists upon an essential distinction between the molecular and vital action. " Chemical compounds," he says, "we know are regulated by the intrinsic properties and the elective affinities of the substances uniting to form them; in organic bodies, on the contrary, the power which induces and maintains the combination of their elements does not consist in the intrinsic properties of these elements, but is something else, which not only counteracts these affinities but affects combinations in direct opposition to them, and conformably to the law of its own operation."
This is an abstract statement of the almost universal proposition, that the vital force overrules chemical action that the body, for instance, resists decomposition while alive, but as soon as life has left it, chemical action resumes its wonted efficiency, and decomposes the substances formerly protected by vital force. This is almost universally believed to be the explanation of an obvious fact. That it is a purely metaphysical explanation I hope the reader sees at once. Vital force is one of the metaphysical entities. A more intimate acquaintance with chemical and physiological phenomena will, I am persuaded, prove the explanation to be wholly erroneous. As Liebig truly says, " So far from there being any foundation for the opinion that chemical force is subordinate to vital power, so as to become inoperative or imperceptible to us, the chemical effects of oxygen in the process of respiration, for example, are seen in full activity during every second of life." He might have multiplied the examples indefinitely. Whenever we think we see chemical force inoperative it is simply because the force is acting in another direction. The same phenomenon occurs in purely chemical combinations. For example, sulphur has an affinity for lead i. e., when the direction of its force is not counteracted by some other direction when its path is not intersected by some other path, it will combine with lead. But if we fuse a mixture of iron and lead together with sulphur in a crucible, the iron separates from the lead and combines with the sulphur; and so long as there is any particle of iron uncombined with sulphur, so long does the affinity of the sulphur for the lead remain inoperative. When all the iron is combined, then the sulphur which remains free combines with the lead. What is this but the analogue of that very process which prevents the decomposition of a living body by the action of atmospheric air, and permits the decomposition of the dead body ? Or, again, when water poured into a red hot crucible is converted into ice, if there be liquid sulphuric acid present, are we to suppose chemical force inoperative because the ordinary effects of heat upon water are thus changed ?
That a great difference exists between chemical phenomena and vital phenomena I have already admitted, and upon that difference rests the necessity for a separation of the sciences of Chemistry and Biology, and consequently the effacement of any distinct science of Organic Chemistry. But this difference is not essential. It does not arise from the presence of a new force, but from the complication of the phenomena owing to the varieties in direction of the one unknown force. It is a new evolution, not a new creation.
An egg is organic, but it is not living. That is to say, its component molecules are so arranged that the application of a determinate force (heat) will give a determinate direction to its molecules, which will result in the phenomena of life. The seeds which were found in Egyptian tombs, where they had lain for thousands of years, were not alive ; they manifested none of the phenomena of life; they might have existed an eternity in that state; yet by placing them in proper conditions they germinated lived. Now there are three explanation of this fact.
1st. The seed had a " vital principle" within it, capable of manifesting itself under suitable conditions.
2nd. The seed received life from heat, which is a "vital principle."
3rd. The seed was a peculiar arrangement of organic molecules, which, when a determinate direction was given to its forces, manifested certain phenomena collectively named life.
The two first are pure metaphysical assumptions ; the last is an abstract statement of what observation reveals.
"If," says Mulder, "we review the phenomena of life caused by a change of materials, we must go back to the original formation of organs to the growth of an individual from a germ. We perceive no greater traces of the future Oak in the Acorn, than of the Chicken in the embryo of the Egg. Should we say that the Acorn is governed by an Oak forming Force, the embryo by a Chicken forming Force ? Though it cannot be denied, that, in the embryo, the rudiments of the future organs of the Chicken are not to be found ; yet we do find the materials from which the first rudiments of organs will be produced, ere we find rudiments of rudiments. The molecular forces, which are inseparable from matter, are present as well as the materials. If in these molecules there exists, no capacity of becoming organs, (i. e., if the directions are not determinately such as will produce organs,) and if in the germ of organs there exists no capacity of ultimately becoming organs, no Chicken at all is produced. This capacity, this predisposition (i. e., this possible direction) must be present in the molecules, otherwise the heat necessary for hatching would be insufficient to produce germs of organs, in the first place, and organs afterwards, (i. e., the direction being different, the result would be different.) This is the only reason why the embryo of the Egg will not produce an Oak, nor an Acorn a Chicken."
To this it may be answered that the cause of the pre-disposition to form organs is the latent "vital principle," or Chicken forming force. But I ask Why assume the presence of this mysterious entity ? How, if the egg be addled, and no organs are produced, where is the vital principle then?
What evidence have you for the existence of any such mysterious entity as the so-called "vital principle ?" The fact that chickens and oaks do necessarily result from certain combinations of matter under certain conditions ? But there is in this process nothing more than we see in the analogues of the inorganic world ; in crystals for example : a solution is before me, having none of the appearances or properties of crystals, yet by a touch with a feather, the whole mass becomes crystallized, and into crystals as definite in form and properties as the Chicken or the Oak. Is there a Crystal forming Force a Crystal Principle latent in that solution? Again : evaporate a solution of sulphate of soda in water, and you get prisms. Are we to suppose that the sulphate of soda exists as minute prisms in the solution, or that a Prism Principle is latent therein ?