# Popular Science Monthly/Volume 13/October 1878/Monera, and the Problem of Life III

 MONERA, AND THE PROBLEM OF LIFE.
By EDMUND MONTGOMERY, M. D.

III.—THE PHYSICAL PHASE OF THE PROBLEM.—(Concluded.)

IT has been shown in former articles that living motion is the result of alternate expansion and contraction on the part of the protoplasm; and we could not fail to perceive that this occupation of so much more or so much less space is the physical property of the protoplasm under different states of chemical composition. It remains to be ascertained by what agencies the chemical composition and decomposition of the living substance are affected. What are the influences that disintegrate the protoplasm? and what are the influences that reintegrate it?

A little attention to the visible changes which occur in the expanding material of different monera, when being checked in its onward course, soon demonstrates that it is the resistance of the medium, the counteraction of the energies composing the immediate environment, which causes chemical rupture in the organic substance. The molecule of protoplasm, like all very high compounds, and, in fact, like almost all nitrogenous compounds, is in a considerable degree explosive. During the expansion of the protoplasm, the medium is pushing against it with a force of its own; and it is this opposing energy, exerted by the medium, which, at some definite moment of its increasing composition and consequent expansion, causes this living substance at last to explode.

No unscientific conjecture has been allowed to enter into the above conception of this highly-important vital occurrence. It is as a mental sketch, in its outline, as positive and certain as any fact of Nature can possibly be.

In observing this process of decomposition, first the outer envelope of the projecting cone is seen to become disintegrated, and, in lower monera, also solidified. In these lower specimens the expanding material pushes still onward along the central axis of the cone, breaking through its apex, until it is at last also overcome by rigidity.

As the expanding material is perfectly translucent, the slightest optical change in it can be easily detected. The whitish, somewhat more opaque appearance of the stagnating protoplasm indicates that an important molecular alteration has taken place. That this alteration is of a chemical nature is actually proved by the products of decomposition being in many instances visibly gathered into a separate globule.

Thus the dynamical energy of the medium applies the match, gives the turning-stroke to the pending explosion, and it is by this dynamical act that the specific chemical rupture is effected, in consequence of which the protoplasm reassumes its former contracted state in space.

In physiology, the peculiar activity displayed by the protoplasm, and induced by the dynamical influence of the medium, is called the function of the acting substance. The function is said to be stimulated by the dynamical influence, and the material compounds which separate from the living substance during this operation are distinguished as products of functional disintegration.

The special function of living contraction, which we have been enabled so plainly to follow up in our primitive organisms, is typical of all motor and sensory functions whatever. Contractility is the fundamental expression of vital function. It is the first unmistakable, distinctly visible manifestation of living activity.

All these functional performances, these visible and otherwise directly sensible parts of organic activity, compose the open spectacle of life—the ostensible conspicuous display of vitality. They correspond to the manifest figurative exhibitions of an exquisitely-contrived clock, all set in motion during its unwinding. But beyond this variegated automatic show perceived on the outside, what depths of unsolved mystery, molecular and other, remain behind in the impenetrable recesses of organization, affording a boundless field for scientific exploration, as well as teleological speculation.

All those of the past and present who, in the stronghold of final causes, have fortified their faith in a spirit of guiding forethought—Voltaire, the sprightly scoffer, with Paley, the sifting advocate, and so many more who have sought to interpret the secret scheme of apparent design traceable in the all-befitting coaptation—of things to me it seems they have but slightly and superficially used their strong means.

The wonder lies essentially in the unification and integration of manifold influences into the compass of one single individual entity, not so essentially in the subsequent spontaneous correlation of that individual to those manifold influences. The wonder lies chiefly in the concentrated and unified organization of the relations, not so much in their functional display afterward. The problem is the established unity of the multifariously related individual, not the planning and fitting of these multifarious relations themselves. The power of our life is intrinsically wrought, not extrinsically derived.

This most weighty truth the science of organization maintains not on mere general grounds or formal conclusions drawn from assumed premises, but it is ready to prove it step by step by actual verification. The subsistence of the reverse supposition is altogether emotional and metaphysical; it rests on fictitious ontology. From foreign spheres an outside hand of power is made to reach forth, and to set going, by dint of will or deed, the precious clock of life, with all its play of sensation and motion, its revealing and its conquering beats. From out the indefinite infinitudes an unlimited skill is evoked, and upon it are imposed the effortless contrivance and accomplishment of all that is so laboriously painful, joyful, marvelous to us.

This, in its best sense, means blind surrender of all knowledge to implicit trust. But life, grown conscious amid incessant struggle and remorseless fate, feels now sufficiently inured and emboldened not to shrink from prying with utmost earnestness into the secret of its own significance. It yearns to comprehend.

However, one obstacle removed, another at once takes its place. It so happens, namely, that we ourselves are most ingenious contrivers, all of us inveterate mechanists from our birth, using with much advantage things that already are. And, very likely, because of such universal human propensity, the advanced thinkers of our race conceive that a chaos of some kind of original stuff must have served a similar purpose to an infinitely mightier contriver, maker, Nature, or whatever special appellation anthropomorphic or metaphysical predilection may dictate for it. Poor philosophy this, that has to beg the entire question. No, we are very far yet from having solved the riddle of final causes and natural synthesis. We stand on the outside, perplexed as ever, in spite of Hume's concentrative naturalism, and Kant's schools of criticism and transcendentalism. No word of prophetic speech, or weighing knowledge, has yet uttered the true meaning of things. Our mind, with its shallow dip, emotional and mechanical, does but pierce the rippling face of creative profundity.

One point, however, one steadfast point, is everywhere discernible among the phantasmal shifting of appearances and thoughts; and this one positive element of truth thus enunciates itself: Only by unremitting, infinitely graduated, indwelling travail, does at all times the fruit of existence receive its birth. The import of this guiding truth can be but superficially reprojected and numerically symbolized by the recognition of signs of inorganic evolution, and the heaping of ages upon ages of geological time. Its real value can be realized only by the discovery and penetration of its actual source of emanation—organization.

Perhaps our monera will materially assist us in gaining some estimate of the potency of organization. In its adequate composition will consist the arduous task of the philosophy of the future.

The study of moneric protoplasm has disclosed that so-called contractility is not merely a property of the living substance, but that it is its function, stimulated by the dynamical influences of the medium, and effected by means of chemical disintegration. The organic molecule, before it experienced its chemical, its functional rupture, was held together by the bond of inwrought chemical affinities. Now that disassociation has been accomplished, these chemical affinities are left unsatisfied. The disintegrated protoplasm forms but one complemental part of a higher, most definite combination. If the other complemental part should happen to be in readiness somewhere, and be brought, by some means or other, into actual contact with the mutilated protoplasm, then surely the existing affinities would exert their influence, and the higher compound would be restored in its former integrity and completeness. This—expressed in the language of chemistry—is exactly what in reality occurs.

The union of the disintegrated protoplasm with complemental material, furnished by the medium, can be directly witnessed without any possibility of misapprehension. We see the disintegrated protoplasm. We see it combine with substances drifted to it by the medium, and we see it in consequence reassume its former state.

Now, at last, we have actually entered the threshold of organization. We have discovered the fundamental fact of its statics. We know positively that reintegration of the living substance, restoration of the disturbed vital equilibrium, is the work of preëstablished chemical affinities, and that it requires extraneous matter of a specific kind to enable this restitution to take place.

The statical aspect of all organization offers nothing but a complication of this one event of chemical equilibrium, a vast complication in the molecular gradations of functionally disintegrated protoplasm, a vast complication also in the gradations of restitutive material.

The integration and differentiation of vital function on the one hand, and the preparation and composition of food-material on the other hand, form—as we will become fully aware further on—the two great divisions in the subject-matter of the science of organization, divisions corresponding to the fundamental biplicity of all advanced organization, its animal and its vegetative life. Organization in the sphere of animal life is the expression of the development of manifold outside relations in the vital unit. Organization in the sphere of vegetative life is the expression of the preparation of more and more elaborate material, fit to restore the functional waste of those developed relations.

I believe no candid critic can deny that the above related observations have laid open to inspection the secret mechanism of life; have reduced to the domain of operations known in the inorganic world the performances that, in a primitive state of life, visibly constitute vital activity.

With little more mental exertion than is required for the faithful interpretation of obvious appearances, a scientific feat has been accomplished which but yesterday seemed totally impracticable. I am aware that, on account of its strange simplicity, many will deem that, after all, not much advantage has been gained by it. But let no one deceive himself in this. By dint of this internal as well as external understanding of motility, we know at this very moment more, much more, about the property of life in the living substance than we do of any other property belonging to any other substance.

We clearly conceive the manner how, and the conditions by which, motility, this most prominent vital manifestation, constitutes an inherent property of the living substance. Do we as yet comprehend in the same way the intimate modes of activity which constitute the properties appertaining to inorganic substances? Is any kind of those peculiar motions which form the scientific essence of the various forces of inorganic Nature so strictly and deeply intelligible as has now become that specific motion which forms the scientific essence of the force of life?

Motion of any kind stands at present just in the same relation to dead matter as that special mode of motion called contractility stood, before this, to living matter. Mechanical motion, heat, electricity, etc., are all qualities occultisimal, known only by the relative measurement of the spaces of contraction and expansion which their manifesting substrata occupy, or are thought to occupy.

Comparative expansion and contraction are, and must be, the subject matter of all quantitative science. All intensities are made quantitatively scientific by being "converted" into modes of space. Time itself is thus measured, and the intensity of heat can be ascertained only by the expansion and contraction of the manifesting substances. So with all. Our undulatory theories are expressions of the same helpful makeshift; an expanding and contracting substratum.

Motility is precisely such another expansion and contraction. But, now, we know not merely the fact. We know, besides, how it is effected. We know something about the working of it within the manifesting substance. By this qualitative penetration, this more substantial insight into natural operations, we have broken the consolidated crust of mere superficial shiftings in space, and have forced a scientific entry into deeper spheres of knowledge.

The comparisons between motility and other modes of motion are strictly appropriate. How much so cannot be adequately appreciated until the origin and development of sensation have been traced; of which all modes of motion are, in the last instance, accurately corresponding affections or reactions.

And, now, what has become of this most vexed problem of problems—the origin of life? Is not protoplasm a chemical compound like other substances, merely varying from them in its degree of molecular complexity? Its most characteristic manifestation, its distinguishing mode of motion, its peculiar force—the one specific activity constituting its most vital difference—is better known to us than any quality which forms the distinguishing feature between other substances. Do we greatly concern ourselves about the origin of MgO,SO3+7H2O, or any other mineral substance? Why, then, should the origin of some combination of C, H, N, O, be made a question of the life and death of our principal philosophies? Has it actually come to this, that the scientific foundation of our creed rests on the decision whether COO is or was once changed into CHO by natural or supernatural means; and this when there is plenty of H about in our world? Yes, it is even so, however incredible, however little flattering to our intellectual pretensions. The contending claims of naturalism and supernaturalism, the fate of the most momentous question touching the guidance of our life, turn actually, in the field of science, upon the paltry issue of the synthesis of ternary carbon compounds, whether this be chemically or whether it be superchemically effected. COO is undisputably an inorganic compound. CHO is undisputably an organic compound. This designates accurately the actual depth of the gulf existing between organic and inorganic Nature.

The chief vital manifestation of protoplasm, its contractility, can no longer startle us, for we know exactly how it is produced by well known chemical and physical means. The combination of C, H, N, O, constituting protoplasm, is nothing but a very complicated chemical compound. CHO is a less complicated compound. COO is a still less complicated compound.

We do not in the least know how COO originates. We know a little better how CHO originates. And, perhaps, it will presently appear that we know still better how the combination of C, H, N, O, constituting protoplasm, originates. The advantage of intelligibility lies all on the side of organic Nature. It is astounding fro contemplate in what a degree this may actually prove to be the case.

We owe an incalculable debt of gratitude to quantitative science. In our panic-stricken minds it has established the certainty of serene order everywhere. Through the never-failing verification of inflexible laws it attests the necessary connection and absolute interdependence of all accessible changes in Nature. Thus it has liberated us from a thralldom infinitely more pitiful than any form of common slavery—the thralldom of our own vicious and cruel superstitions. In many ways it has enriched our lives a thousand-fold, and we may, in future, expect from it an ever-increasing harvest of similar benefits.

It appears to me as if I could discern with some degree of distinctiveness—just beginning to loom in the distant twilight of consciousness an entirely new era of knowledge; an era governed by the science of organization, by means of which more concentrative appreciation the synthesis of reality will receive a deeper explanation, and all facts of Nature appear in an organic light, in a qualitative interdependence, evolution being then understood as creative evolution, and not as mere transformation of modes of motion and atomical redistribution of matter. I have conjured up into the medium of shadowy words this most vague fancy of an organic epoch in science, because I firmly believe that we are already in possession of a clew to the means and ways by which the development of the living substance has been and is still being achieved; while, on the contrary, we possess no clew whatever to the means and ways which have led to the development of the now existing inorganic substances from the supposed primordial substratum.

We watch a moner for hours, for days. There it is, ever continuing without intermission to expand and to contract; alternately to suffer decomposition and to accomplish its recomposition. A blank sameness, an almost thought-paralyzing monotony of life, is thus exhibited by many of these primitive beings. Only always expansion and contraction, by means of that same kind of reintegration and disintegration. Nothing more, apparently. It would almost seem as if the anti-evolutionists were right after all in their main view of life. It, indeed, resembles most strikingly a perpetual seesaw; the very same thing always over again—a mere organic toy, ingeniously contrived, so as to maintain itself intact, in spite of encroaching outside influences; the unmeaning disturbance of a most delicate equilibrium, and the following exact reëstablishment of that very same equilibrium. This, reduced to its most simple biological expression, is the foundation of the opinions which oppose evolutionism by maintaining the permanence of organic species, or their archetypal origin.

All turns upon the decision of the following point: Does there exist an absolute equivalence, a total identity between the compound separated from the protoplasm by the dynamical influences of the medium and the restitutive compound taken up from the medium by dint of the specific affinities inherent in the protoplasm? Does there normally exist a complete fixity in the observed play of equilibrated activities? Does this ever-reiterated exhibition of motility fulfill only its own motory object? Or, translated into the language of volition, Does the organism merely move to feed, and feed to move? This, in truth, is the pith of this momentous question.

The chemical affinities inwoven in the protoplasm are, like all chemical affinities, of a most definite kind. This chemical definiteness is even outwardly manifest in the strict preservation of all peculiarities in the different living substances which constitute the varieties of monera. Now, this functional restitution of protoplasm is effected entirely by means of these inherent chemical affinities. It is clear, therefore, that, if a deviation is ever to occur in the beats of this chemically so firmly established vital pendulum, it can be operated only in two ways: Either the dynamical influences succeed in splitting off from the expanding protoplasm a slightly-differing molecule, affecting thus the total chemical equilibrium in such a manner as to bring about a somewhat altered reintegration of the same, or the restitutive material possesses, by dint of its own peculiar molecular composition, the power of forcing the disintegrated substance to reintegrate itself with some slight deviation.

In other words, variations in the molecular constitution of the protoplasm can only be effected either by the dynamical influences of the medium, or by the restitutive material of the medium. Spontaneous variations, starting from within the already-established molecular equilibrium of the protoplasm itself, would be like all other spontaneous changes, an inadmissible supposition, an effect without a cause. In another stage of the inquiry we will learn the exact effect which restitutive material, when not accurately complemental, does actually exert on the protoplasm. I will here only mention that it has, very demonstrably, only the power specifically to deteriorate the same, and not in the least the power to give it any impulse toward higher development. In the course of organic progress it is the living substance which lifts the food to the level of its own requirements; not the food which confers higher vital powers on the protoplasm.

There remains only one path, then, through which development can make its entry into the living substance, and this is—be it fully understood—the infinitely toilsome elaboration of molecular complexity by means of ever-reiterated functional disintegration. If it, namely, should happen, that the dynamical influences of the medium are so attuned as to shift and complicate—by force of their sundry specific modes of operation—the molecular equilibrium of the protoplasm, ever so immeasurably little at a time, then, by incessant perseverance, an appreciable organic effect may, at last, be attained.

There are strong reasons which make it highly probable—I do not say certain, because it lies in the nature of the process that it cannot be directly witnessed—but there are manifold occurrences which make it very evident that this mode of development is actually the one adopted in Nature.

In a general way we all know, with perfect certainty, that previous functional exercise of an organ fits the same all the better for further functional performances. Use develops functional structure; disuse involves its atrophy. All educational acquirement rests on this foundation, and also all degradation of skill or culture.

We will endeavor to form some mental representation of the activities which are elaborating these great and evident results.

The energy of the dynamical influences is exerted on protoplasm in the course of chemical composition. It is a substance in process of molecular cumulation which encounters, in its onward flow, the forces of the medium. The foremost part of an advancing conical projection, for instance, will consist of higher material than its lateral part, and will therefore be differently affected even by the same forces of the medium. But, if we further take into consideration that the influences of the medium are themselves of a manifold nature, each kind affecting the protoplasm with a specific energy of its own, it can be readily conceived that a most complicated molecular disturbance must ensue. This must be all the more the case in a substance in which the forces of the medium have not each their definite, circumscribed, and attuned channel of functional stimulation; but are attacking more or less every part of its circumference.

Dynamical considerations, too abstruse to be here introduced, make it extremely probable that a preponderance of effect in favor of the dynamical energies best attuned to the highest, foremost portion of the expanding living substance will give rise to a restitution of the entire mass more in the likeness of the higher protoplasm disintegrated by the more subtile dynamical influences. Thus the constitution of the protoplasm at the very beginning of its next pulse of recomposition will, by this slight increment of complication, resemble a whit more its molecular state, when at the height of its former expanding pulse. The decomposition caused by the combined specific energies of the medium will be followed by a somewhat higher composition.

The elaboration of organic substances in plants is at all times notably effected by a process similar to the one here indicated. It is brought about by a twofold chemical activity, incited by a specific dynamical influence of the medium. First there occurs a specific decomposition, and then, in consequence, a somewhat altered recomposition; or, technically expressed, there occurs reduction followed by substitution. It is believed that under the influence of light there is split off from carbonic acid one atom of oxygen, which is then replaced by one atom of hydrogen:2COO ${\displaystyle +}$ H2O-C2H2O2 ${\displaystyle +}$ OOO.

But, before examining the conditions under which this fundamental and most weighty transformation of the inorganic into the organic takes place, I will state, in further support of the gradual development of the living substance, that the phenomenon of individual growth gives in itself plain evidence of organic development having actually occurred in the past. Growth is essentially a concise recapitulation of developmental changes.

But, not to complicate matters too much, I have here purposely left out of consideration all manifestations appertaining to growth, as well as those appertaining to propagation. Both these phases of organic existence do not belong to the domain of production, but entirely to that of reproduction. Propagation multiplies, growth reconstructs, organic results previously achieved.

Though it cannot be denied that the attentive observation of moneric protoplasm has restricted the physical phase of the problem of life to the limits of a purely chemical question, and though it may be conceded that organic development is truly effected by means of chemical activity dynamically incited, yet with many there will persist an ungratified curiosity concerning the origin of life. This dissatisfaction, expressed in clear words, can only amount to the following objection: "Granting that motility is merely the scientifically intelligible property of a specific chemical compound, yet it has not been shown how on our planet the first organic compound has actually started into existence."

Against this rather radical claim on the science of life might be urged, that we do not precisely know how, for instance, carbonic acid has naturally originated. But we will be told that one has only to bring carbon, under certain known conditions, together with oxygen, and that then carbonic acid will invariably result.

To this might again be replied that organic substances can also be made to originate in the same manner; that from inorganic material Woehler produced urea, Strecker taurin, Kolbe acetic acid. etc.

However, I am perfectly aware that this is not the kind of information which will satisfy the somewhat unscientific but historically justifiable craving for positive and circumstantial enlightenment concerning the origin of living substance. The desire is to understand the genuine organic synthesis which has legitimately led to the formation of such peculiar compounds as now actually manifest vital phenomena.

With the protest, clearly defined, and well sustained in these pages, that this question is not at all one of vitality, but merely one of specific chemistry, I will venture a few tentative gropings. Their verification would constitute not a biological but a purely chemical task.

The transformation of the inorganic into the organic world is at present, so far as we are aware, exclusively accomplished by the mediation of protoplasm, containing that peculiar kind of coloring-matter to which the greenness of vegetation is due, and which has received the name of chlorophyl. This chlorophyl-tinged protoplasm is the substratum in which carbonic acid is deprived of its oxygen, and organically incorporated. Here, and here alone, organic substance originates in Nature.[1] It is the one magic gate through which the inorganic effects its passage into the organic; the one transubstantiating medium by which the death-like spell of inertness is broken and the dormant energies of matter admitted to bloom forth into life.

By what agencies is this stupendous chemical feat, this vivifying transmutation, wrought? How is so signal a synthesis of material constituents dynamically incited? If we possessed no further knowledge concerning this initial shaping of organic compounds, it might be supposed that the chlorophyl-tinged protoplasm exerted some kind of catalytic influence on carbonic acid, causing by its mere presence decomposition of the same, and affording thereby to the free carbon an opportunity of entering into the organic nexus. But it is far otherwise—exceedingly more wonderful.

Prompted by Priestley's discovery of oxygen—the vivifying gas inhaled by animals and exhaled by plants, and its contrast to carbonic acid, the suffocating gas exhaled by animals and inhaled by plants—the entire scientific world, during the first decades of the present century, became deeply agitated by the recognition and elucidation of what was called the chemical and physiological balance of organic Nature."

It was taught—and to the present day this teaching forms the groundwork of most physiological conceptions—that plants imbibe and reduce carbonic acid furnished by animals, forming therefrom organic compounds of high calorific value; and that these food-compounds reunite in the animal with the oxygen inhaled by it, yielding by this combustion all the power exhibited in its vital manifestations.

While this—from our present point of view—fundamentally erroneous and most misleading conception exerted an all but universal sway over scientific minds, it happened that, under its influence, so early as 1844, our illustrious and veteran scientist and philosophical historian, Dr. John W. Draper, succeeded in establishing, by a series of beautiful experiments, a far deeper and vastly more essential connection in Nature.

This connection, if I am not greatly mistaken, is destined to become the redeeming thread by which Science will extricate itself from the mechanical maze of rigid resistance and equivalent mass-motion. By dint of so significant and mathematically available a clew, it may in time reach a somewhat more commensurate recognition of effects synthetically secured, of inherent cumulative elaboration, the unforfeitable boon of specific dynamical influences, which with restless toil are ever busy, widening the scope of qualitative wealth, intensifying the intestine sensitiveness and sympathetic response by which substances inwardly answer the inward call of other substances.

The marvelously slender thread of vivifying connection, traced to its origin by Draper, is an ethereal but most definite band of vital dependence, absolute dependence. It is a truly promethean beam, for without it no life, no fire on earth. You suppress from the entire amount of solar influence—calorific, luminous, and chemical—solely the yellow rays, and you have quenched life at its starting-point: no more elaboration of organic compounds by chlorophyl-protoplasm, no more food-supply, no more vitality. You have cut off the thread of life, the golden band of union by which the still embryonic vitality of our planet receives sustenance from the mighty parent-orb. This great discovery of Draper the recent researches of Sachs and Pfeffer have only essentially corroborated.

It is here, then, that the knot of organic complexity is being really tied in Nature, and this is, therefore, the exact point at which the mystery of organic synthesis has to be unraveled. A most specific dynamical influence meets here in a peculiar preexisting substratum with certain inferior matter, and under this confluence of conditions, by a chemical process of reduction and substitution, molecular organization is effected.

In framing my hypothesis of the origin of organic compounds on our globe, I would closely adhere to the above facts. After what I have learned with regard to the yellow rays, I would not expect aboriginal organic synthesis to have taken place at the bottom of the sea, where all dynamical influences must be dispersed, or so suffused as to have lost their definite efficiency. I would then imagine some probable preëxisting substratum—some compound of silicium, for instance. Silicium is evidently a very wonderful substance, strangely like carbon in many respects. It is capable of existing in at least as many similar molecular modifications; and, above all, some of its compounds, though inorganic, occur in the colloid state.

It would not be an extravagant supposition to assume a film of some such colloid compound of silicium floating on the top of the sea, exposed to specific solar influences, imbibing carbonic acid from the air, and being traversed by currents of sea-water, holding carbonate of lime and other salts in solution. Under such favorable circumstances it is not altogether improbable that carbon may have actually by degrees been chemically substituted for silicium, and that thus the first hydrocarbons were allowed slowly to slide into existence.

When we consider what a prominent part silicious and cretaceous organisms play in the history of our globe, it would not be so very astonishing to learn that the inorganic substance has to be looked upon as the original matrix, and not merely as the skeleton of such organisms.

There may have been an age in which silicium was the leading element, followed by an age in which lime ruled organic composition, followed again by an age in which Carbon and Company is the thriving firm, to be supplanted by an age in which nitrogen will be foremost, till this also is forced into the background by phosphorus, etc.

It would not be difficult to fill a volume with plausible reasonings in support of the above nevertheless completely hypothetical conceptions. Side by side with the great and positive truths revealed by the study of incipient motility, truths most scrupulously verified during years of closest application, I would have grudged such fanciful conjectures even the little space here allotted to them, if it had not been my intention to invoke their assistance by way of contrast.

It cannot be too forcibly impressed on all who take an earnest interest in science that we have constantly to bear in mind the radical difference obtaining between verified scientific results and analogical scientistic suggestions. The former represent tasks performed, the latter tasks imposed. The former constitute our accredited store of premises, on the ground of which we may with some safety indulge our reasoning propensities; the latter is the more or less skillful performance under such reasoning license. To reason from premises not verified as forming an integral part in the necessary enchainment of natural events is, however, to move in a world of thought in no way contiguous to the realm of science.

Whoever, therefore, wishes to form an opinion regarding the truths here advanced, whether they be in strict accordance with Nature, or whether they be merely mistaken interpretations, need only to examine monera for himself.

Motility is the key to the understanding of vitality and organization. With little trouble any one can now convince himself that living motion is actually accomplished by the operations which I have here disclosed.

A certain organic substance expands under chemical composition, and afterward contracts under chemical decomposition. Its disintegration is incited by the dynamical influences of the medium; its reintegration is brought about by its own inherent chemical affinity, which affinitive power effects its combination with complemental material furnished by the medium.

In pursuing the inquiry here begun, the next step would be to show how complications of these sundry phases of the one central fact of motility lead to definite organization in various directions, and to the rise of sensation.

1. The experimental synthesis of organic compounds, found to be accomplished, under certain artificial conditions, by normally parasitic organisms, containing no chlorophyl, need not be taken into consideration in the above argument, however interesting in itself it may otherwise prove to be.