Some chemical difficulties of evolution

Front matter

A CRITICAL EXAMINATION

OF

By JAMES MACLAREN, M.A., Barrister-at-Law.

Preface

those most difficuH and most obscure of all the problems which the chemistry of nature presents to us, namely, the origin and the mode of action of that mysterious power which we call life ; and our sui-prise is certainly not lessened when we find that these speculations have been accepted without waiting for the opinion of the scientific chemists of the day, and that the faith of the believers is actually so strong that they have not hesitated to charge so bold and original a thinker, and so distinguished a philosopher, as Mr. Darwin, with being untrue to himself — nay, with want of moral courage — because he will not accept their supposed solution of these chemical problems as part of the body of established scientific truth.

I cannot help thinking that the present state of chemical science is in some degree to blame for the line which popular opinion has taken on this subject. Every work on chemistry which gives a full account of the principles which have been established, is filled, and necessarily filled, with a mass of repulsive-looking formulae, and a wilderness of small details, which make it highly distasteful to the general reader, and which certainly render it difficult for him to pick out the special facts and to select the particular general principles which bear upon the subject of Evolution. I have therefore, in the following pages, endeavoured to collect these facts and princij)les, and to place them before my readers in a convenient shape, with the object of enabling those who have not devoted any time to chemistry to form a fair estimate of the diffi-

PREFACE.

V eulties which the Evolutionist has to meet before his theory can be ranked among the indisputable facts of science. I have purposely avoided the use of formulge and of technical language as far as possible ; and where the use of technical words could not conveniently be dispensed with, I have given definitions of the terms which will, I trust, make them both intelligible and useful to the general reader.

For the sake of greater simplicity I have divided the subject into three parts : in the first I have endeavoured to explain the nature of chemical action, where life is absent ; in the second I have examined those more comphcated cases where living beings take part in inducing the changes observed ; and in the third I have attempted to point out the bearing of the principles explained in the first two parts upon the doctrine of Evolution and the views of Mr. Darwin, and to lay the difficulties which these principles raise fairly before my readers.

I have only, in conclusion, to remind those who have not made a study of chemistry that there is little or nothing novel in the chemistry which they will find in the following pages, and that the principles there stated are not mere speculations, but for the most part explanations founded on experiment and approved by the whole body of chemists ; and, in fact, I have to ask the kind consideration of any chemical readers for that repetition of well-known facts and familiar principles which the plan of my work has impased upon me. I have endeavoured to confine this repetition as vi

PREFACE.

far as possible to the first and second parts of my inquiry ; and I would suggest that any such readers should pass over those parts^ and turn at once to the third part, where I have discussed the theory of Evolution and the views of Mr. Darwin, with reference to the chemical compounds met with among the various forms of life.

J. J. MACLAEEN.

March 2nd, 1877.

Contents

INTKODUCTORY CHAPTER,

The theory of the evolution of life from non-living matter an extension of Mr. Darwin's views — The works in which it is put forward leave out of sight the chemical difEerences between the forms of life — Number and importance of these — Can the theory explain their existence satisfactorily — Supposed simplicity of a being composed of protoplasm only — Chemistry proves this substance to be a structure of astonishing complexity — Proposed course of the inquiry as to the chemical difEerences which living beings present . . 1

Part I. Chemical Action Where Life Is Absent

CHAPTER L

THE STEUCTtTEE OF MATTEE — ATOMS AND MOLECULES.

Three states of matter, soM, liquid, and gaseous — Sensible portions of matter are structures of some kind — Subdivision of a piece of ice by mechanical force — Further subdivision of the ice-matter by the action of heat — Division of the ice-matter into oxygen and hydrogen by the action of an electric current — Relations of weight and volume between the quantities of the new substances — Summary of the results of the experiment— Experiments on other bodies — Elementary substances — Law of combination in definite proporviii

CONTENTS.

tions by weight — ^Atomic theory — Definition of atom — of molecule — ^Atomic weights of the different elements — Properties of gases — Eeceived explanation — Molecules, and the manner in which they are connected in sohds, liquids, and gases — Law of Ampere — Comparison of such molecules in the case of a compound with the molecules of the atomic theory — Are the two molecules identical — What is the atomic structure of the molecule of an element — Experiment of combining equal volumes of hydrogen and chlorine to form hydrochloric acid — The molecules of hydrogen and chlorine each contain two atoms — Gaseous molecule of hydrochloric acid identical with its molecule as defined by atomic theory — Similar results of other experiments on gases — Atomic sti'uctui'e of the molecules of various elements — Complete agreement of conclusions with the relation between the volumes of hydrogen and oxygen obtained in the experiment on the ice-matter — Other similar coincidences establish the theory- Independent confirmation by the theory of heat — Distinction of the chemical atom from the atom of the philosopher — Size of the molecule of water — Its invisibility under the naicroscope — Probable size of molecule of protoplasm . . 8 — 34

Chapter II

THE ATOMIC STRUCTUEB OP MOLECULES — QTJANTIVALENCE — MOLECULAR EQUILIBRIUM — CAUSES OP CHEMICAL CHANGE.

AH atoms do not play an equal part in completing the structure of a molecule — Architectural value of the various elements— No element of a lower architectural value than hydrogen — Hydrogen the standard of reference — Difference in architectural value does not depend on chemical affinity — Variation of the same substance in architectural value — Definition of quantivalence — Classification of elements according to quantivalence — Hypothetical structures foi-med by uniting atoms by bonds — Suppositions requisite to make these structures identical with the molecules met with in nature — Relations between the bonds when the real molecules are represented by such structm-es — Law of molecular equiUbrium — Qualification when it is extended to compound molecules containing multivalent atoms — Known forms of molecule among the elements— Universal application of the law of mole-

CONTENTS, ix cular equilibrium in its qualified form — Differences in tlie intensity of the chemical action between the atoms of different elements — Nature of the atoms composing a molecule ought theoretically to affect its stability — Experimental confirmation— Definition of chemical change — of molecular change — Distinction between the two kinds of change — Law of molecular equilibrium proves that all chemical change is due to force applied from without —Essential identity of all the known forms of physical force — All may take part in causing chemical change 35 — 46

Chapter III. Mode Op Action Of Chemical, Fokce

mical action due to some mode of motion affecting the atoms themselves — Nature of the movement at present involved in obscurity — Chemical affinity a polar force — Probable explanation of the phenomena of quantivalence — Change in quantivalence always due to force in form of chemical affinity — Distance a material element in the action - of chemical force — The distances at which the force acts probably comparable with the magnitudes of molecules and atoms — Test of the law of molecular equilibrium — Relative position of atoms in a molecule, and nature of the action of multivalent atoms, ought to affect stability of molecule — Isomerism — Cases in which chemical change may be expected to take place — Three classes of cases — Those due to chemical force alone — Those due to other forms of force alone — Those due to the joint action of chemical and other forms of force — Examples — All instances of chemical change where life is absent fall within one or other of these classes — Difficulty in distinguishing between chemical and molecular change in complex cases — Difficulty in giving a complete explanation of such cases 47 — 57

Chapter IV, The Steuctuee Op Sensible Masses Op Mattee

Our defective knowledge of the subject — Our comparative ignorance of the laws which govern the formation of crystals — Our almost complete ignorance of the laws determining the

X

COJS"rEJ>JTS.

fonnation of other bodies — Two very distinct types of construction— Crystalloids — Colloids — DifEerence between these bodies probably due to difference in the structure of their molecules — Atomic structui-e of colloids as compared with crystalloids — Apparent influence of multivalent atoms in giving rise to colloids — Complexity of the atomic structure of colloids — Probable energy of such molecules — Probable size as compared with the molecules of crystalloids — Peculiar properties of colloids — DifiEusion — Inability of colloids to diffuse through a colloid partition — Separation of colloids from crystalloids by virtue of this property — Eemarkable chemical changes attendant on such separation — The formation of colloidal oxide of iron as observed by Graham — Probable explanation of the reaction— A good example of the difficulty of distinguishing chemical from molecular change — Colloidal oxide of iron a typical colloid — Never shows any trace of life — Importance of this fact . . 58 —

CHAPTEE V.

INFLUEIfCE 01" TIME XSJ) MASS IN PKODTJCING CHEMICAL

CHANGE.

General points which apply to both coUoids and crystalloids — Time required to complete any chemical change taking place between sensible masses of matter — Influence of mass on the result — Probable theoretical explanation of the facts — Test by examination of the reaction between compounds in mixed solutions — Experimental results — Our want of knowledge of the exact nature of solution— Application of theory to the results obtained — Similar changes when reaction takes place betweeii bodies in a state of fusion — Agreement of theory with experiment in these cases 68—

Chapter VI. Surface Action

Cases where non-living bodies cause chemical change whilst themselves remaining unaltered— Two classes of changes of this kind— The first a mere ordinary chemical change— The second class— Action of finely divided platinum on

CONTENTS.

xi mixture of gases — Reasons for giving this action the name of sul-face action— Similar actions of other bodies— Laws of surface action— Similar results of surface action in solutions — Nature of the phenomena of surface action . . 76 — 81

CHAPTER I. THE CHEMICAL ACTION OF LIVrNG BEINGS — GEOWTH

Identity of the essentially living part of all living beings — Protoplasm— Protein compounds — Atomic structure of these compounds — AH are colloids— Great complexity of theii' atomic structure — Manner in which the sulphur and the phosphorus are combined in these bodies — Professor Huxley's account of the growth of a spore of mould in a solution containing tartrate of ammonia, phosphates, and sulphates — Chemical examination of the phenomena presented — Formation of the mixed solution — Probable reaction — No formation of colloids — Introduction of the mould spore — Breaking up of the chemical molecules which ensues — Result not due to mere chemical action between the atoms contained in the spore and the substances in solution — Nor to any form of suiiace action exerted by the spore — Not accounted for by the action of heat or any other known form of physical force supplied from without — The spore itself exerts force — Vital force — Nature of the evidence given by growth — Supposed analogy between the growth of a crystal and that of a living being — Comparison of the phenomena exhibited in the growth of a crystal, the decomposition of water, and the growth of a living being — The supposed analogy does not exist — Whence was the vital force obtained — Phenomenon of death— No sufficient reexson for disbelieving in the existence of vital force— Illustration from the solution of a steel magnet — Our inability at present to correlate the force of vitality with other forms of force — Not a valid objection to belief in vital force . . 82—100 xii

CONTENTS.

Chapter II. Higher Forms — Vegetable Life — Animal Life

The spore unable to decompose carbonic anhydride — Plants able to do this — Chlorophyll — Its composition — Growth of a wheat plant — Destruction of molecules of carbonic anhydride and other simple substances — Manufacture of protoplasm out of atoms thus procured — Marvellous nature of the chemical change effected — Extreme stabiUty of the molecules of carbonic anhydride — Extreme instability of protoplasm — Contrast between the enormous power exhibited in tearing up stable molecules and the wonderfully delicate manufacturing power exhibited in the production of protoplasm— Animal life — Animal heat — Animal manufacturing power— Animals, like plants, exhibit vital force — Complexity of the materials required by animals for their laboratory — Phenomena of voluntary motion and of mental power — Comparison of animal with vegetable life . . , 101 — 107

Chapter III. Nature Of The Action Op Living Beings

Properties which distinguish all living matter, whether vegetable or animal, from dead matter — These properties primarily due to vital force — Attempts to account for the properties in a different manner — Life not due to the semi-fluid state of aggregation of protoplasm — Nor to the mere chemical composition of this substance — Hlusti'ation from the magnetism exhibited by the loadstone — Dr. Bastian's view — It fails to explain the varying extent to which the protoplasm of different living beings transforms physical force — or to account for th6 phenomenon of death — Isolated position of living protoplasm if regarded as a mere transforming agent — Apparent impossibility of transforming vital force into any known form of physical force — Probable occurrence of spontaneous generation if Dr. Bastian's view be correct— Life not the result of organization— Life still a mystery— Test of its existence in any given portion of matter— Class of changes to which the chemical actions of living beings belong— Are the products of living beings true chemical compounds — Their uniformity of composition— Probable inference— Phenomena of dccomposi-

CONTENTS, xiii tion after death— Application of the law of molecular equilibrium— General conclusions on the nature and causes of the chemical actions of living beings .... 108 — 124

Chapter I

THE THEOBIES PTTT FORWARD TO ACCOTOT FOR THE EXiSTEJSrCE AND VARIETY OF THE FORMS OF LIFE.

Probability on astronomical grounds that the earth has cooled down from an intensely heated state — Inference as to the probable antiquity of life — The Evolutionists accept the view that the earth was once intensely heated — The teaching of geology as to the appearance and disappearance of special forms of life — The individuals of all existing species are the offspring of similar parents — If we exclude hybrids, no case known where a species can be directly traced back to ancestors substantially different — The hypotheses put forward as histories of the production and development of life — The Creationist's view — The Evolutionist's view — Its completeness — Mr. Darwin's view — Consistent with either view of the origin of life — Points common to Mr. Darwin and the Evolutiom"sts properly so called — Necessary consequences of these points — Their application to the chemical products manufactured by living beings . , . 125 — 134

Chapter II

THE BEARING OF THE THREE VIEWS ON THE SPECIAL CHEMICAI, PRODUCTS MANUFACTURED BY LIVING BEINGS — THE ORIGIN OF LIFE.

The Creationist's view — Its sufficiency to explain the phenomena — Absence of experimental confirmation — Status of the view as a scientific theory — The Evolutionist's view — Necessary simplicity of the first living forms — What were the conditions which enabled the physical forces to produce a living being— Can the cooling of the earth have supplied any xiv

CONTENTS.

sufficient conditions — The original form of life could not have existed until a temperature below that of boiling water had been reached — Existence of the inorganic chemical compounds met with in nature, prior to that time — Insignificance of the change to which the production of life is attributed — Conditions of the production and continuance of life as conceived by the Evolutionist — Loss of a trifling amount of heat insufficient to account for the production of life — The Evolutionist assumes the occurrence of a miracle — Superior logical position of the Creationist — Production of protoplasm in former ages — Chemical condition of the available carbon in ancient times — Laws of Berthollet — Chemical conditions of our globe when life is supposed to have first appeared — Far less favoui'able to the production of protoplasm than the present conditions — Nature of the difficulty experienced by chemists in forming complex compounds, such as protoplasm — The greater the supply of force in ancient times, the less the probability of the production of protoplasm — The Evolutionist view of the origin of life is to be rejected as a scientific theory .... 135 — 152

CHAPTER IIL

THE EVOLUTIONIST'S VIEW CONTINUED — THE DEVELOPMENT OV SPECIAL CHEMICAL COMPOUNDS.

The archigonic moneron — mass of homogeneous protoplasm — The production of special chemical compounds on Evolutionist principles from the starting-point of the archigonic moneron — Hypothesis of the action of the physical forces — Reasons for rejecting it — Hypothesis of change in the manufacturing power of protoplasm — Not open to those who deny the existence of vital force — Reasons for rejecting it when the existence of vital force is admitted — Hypothesis of change in the actual substance of protoplasm — Production of chlorophyll from protoplasm — Conditions of the problem given by actual observation — Conditions imposed by the principles of evohition — Marked absence of any intermediate body capable of decomposing cai-bonic anhydride — Inutility of any compound connecting protoplasm with chlorophyll — Other changes in the plant must have coincided with production of chlorophyll — Increase of light will not account

CONTENTS,

XV for the change — Chlorophyll cannot have been produced suddenly, or by a series of tentative experiments — The Evolutionist fails to account for the occurrence of chlorophyll, which is absent in the simplest existing forms — The portion of the blood which contains iron in combination — ■ Its importance — Its chemical composition — Nature of the change involved in completing a molecule by the addition of an atom of ii'on — The part of the blood which contains iron cannot have been developed fi"om protoplasm by simple evolution — or produced suddenly, or by a series of tentative experiments — The Evolutionist fails to account for its occurence— Extraction and utilization of silica by living beings — Difficulties presented by the process — Number of cases resembling those already examined .... 153 — 184

Chapter IV

THE evolutionist's VIEW CONTINUED— THE EVIDENCE AT PRESENT BEOUGHT FORWARD.

Relative importance of the various special products met with among living beings — Classification of such products — The single class which may be an example of development by

evolution contains products of minor importance only •

Objections to the application of the theory to even this class

The evidence on which the Evolutionist relies — It does not afEord any well-established instance of the formation of a new chemical product by a living being — Nature of the evidence required to estabhsh the production of the usual compounds from new raw materials — and to establish the fact of the use of new elements — Absence of such evidence- Absence of evidence proving the formation of a new compound fi-om familiar raw materials— Variations in the quantity of any product produced are not cases in point — Cases of the formation of new products under the influence of injuries not in point — Differences in the colour of individuals do not supply the evidence required — Absence of evidence of the formation of new chemical compounds among living beino-s transported to a dijfferent climate or domesticated— Summary of the objections to the second part of the Evolutionist's view— The Evolutionist's view erroneous on the points in which it differs from Mr. Darwin's view , , , 185—197 xvi

CONTENTS.

CHAPTEE V.

MR. DARWIN'S VIEW.

DifEerences between Mr. Darwin's view and the Evolutionist's view — The dLEEerence one of principle— Advantages presented by Mr.- Darwin's view — Possible suppositions as to the chemical products met with among the original forms — Kelative probability of such suppositions— Number of special products met with among living beings — Difficulties thus raised — The Darwinian not precluded from supposing that the manufacturing powers of living beings vaiy — This a question of evidence — The law of variation — Opposite action of the laws of chemical combination — Improbability a priori of any indefinite variation among the compounds produced by two individuals of the same kind — Onus of proof that the manufacturing powers of living beings vary is on the Darwinian — The evidence adduced — Its comparative value ■ — Its deficiencies — Its insufliciency at present to bring the production of any chemical compound within Mr. Darwin's view — Probability that this ■will ultimately be eifected as to some compounds of minor importance — Example illustrating the difiiculties previously discussed — The changes with which Mr. Dai'win has actually dealt in his works are invariably molecular changes — The nectary of the Angrascum sesquipedale — The machinery of the leaf of Drosera — Numerous similar instances in his works — Restiicted application of his view rendered necessary by the present state of the evidence — The application of the view to changes of form and shape beyond the scope of the present inquiry . 198 — 212

Chapter VI

CHEMICAL FACTS WHICH POINT TO THE EXISTENCE OF SOME MORE UNIVERSAL CAUSE THAN THE ACTION OF NATURAL SELECTION AND INHERITANCE— GENERAL CONCLUSIONS FROM THE WHOLE INQUIRY.

Chemical facts suggesting some other possible cause for part of the similarities between living forms — Connecting links between distinct chemical compounds — The North British Reviewer and Mr, Maclaren's comments on his ai-ticle

CONTENTS.

XVll

. — Occurrence of groups among the elements — The relationships between the members of such a group would in the case of living beings be referred by Mr. Darwin to descent from a common ancestor — The halogens — Compai-ison of their properties — They form a well-mai-ked gi'oup — Other families among the elements — Groups among compounds — Probably due to similarity in composition — Application of this argument to living beings — Even elements are not invariable in form — AUotropy and dimorphism— The extraordinary variety of living forms the real wonder — Bearing of these chemical facts on Mr. Darwin's view — Summary of the difficulties which Mr. Darwin's view still presents to the chemist — Estimate of the present position of the view — General conclusions from the whole inquiiy — The origin of life an unexplained mystery — The formation of the most important chemical compounds as yet unexplained — Position of Mr. Darwin's view — Eeal nature of the difficulty which besets the subject — Any further light on these matters must come from the study of chemistiy — Present position of that science with reference to the inquiry — Position of the Creationist's view at the present time — The aui-hor's own conclusions ■ 213 — 231

SOME CHEMICAL DOTICTILTIES OF EVOLUTION.

Chapter I. Introductory

The theory that all the forms of life which we find surrounding us have descended from a common ancestor, and that this common ancestor, this first of all living forms, was called into existence at a remote X period of the world's history by the action of ordinary physical force on part of the non-living matter of which our globe consists, has lately attracted much attention, and has been accepted by a large number of persons.

That it has been so accepted is in great measure to be attributed to the views which Mr. Dai'win has put forward with great force and ability in support of the position that the observed differences between specicB can in the main be accounted for by small

CHEMICAL DIFFICULTIES OF EVOLUTION.

variations perpetuated by descent, and preserved by the advantage they gave their possessors in the battle of life. Mr. Darwin, however, does not himself assert that all forms are descended from one, and that this form was called into existence by the action of ordinary physical force; these positions are "extensions " of Mr. Darwin's views, which, so far as the writer has been able to discover, have been obtained, not by making further experiments, but by framing theories from the facts which Mr. Darwin and his followers have collected and arranged in support of his views.

If now we take up one of the works in which these extended views are put forward, such as Hseckel's "History of Creation," two points will strike us as especially worthy of remark. (1) That our author professes to give a complete history of the origin and progi'ess of life, to account for all the phenomena we observe among living beings, and to lay down an authentic pedigree for each living creature, which accounts for every peculiarity which this creature exhibits. (2) That in tracing the long chain of descent connecting the highest living being with the original form of life, the force of chemical attraction, and the laws which govern chemical combination, are referred to once, and once only, namely, where an appeal is made to the action of ordinary physical force to account for the production of the first living form. We are told that the appearance of this form was due frO the production of a chemical compound, to which

INTRODUCTORY.

the names of " protoplasm " and " matter of life " have been given, and that the essentially living part of every creature, as distinguished from parts used for purposes of support, defence, and so on, is composed of this substance. When this has once been pointed out, the chemistry of life is entirely put on one side ; we hear nothing of any differences between the chemical compounds met with among the various forms of life, nothing of any differences between the chemical results of the life of different forms of being ; and the non-chemical reader might at least be pardoned for supposing that no such differences were met with in nature.

We need hardly say this is far indeed from being the trath. Many of the most important and essential parts of living beings, parts which are as absolutely necessary to the continuance of their life as the " matter of life " is to the existence of this life, differ extremely in chemical composition among different forms. Some of these compounds contain elementary substances which are altogether absent, not only from the other special compounds we have referred to, but actually from the " matter of life " itself. Others are marked by the possession of chemical properties so singular that the chemist is forced to consider them as among the most wonderful productions met with in the whole world of nature. And lastly, the occurrence of these special compounds is as marked and constant a point of distinction between different forms of life as any of those differences of shape and struc-

4 CHEMICAL DIFFICULTIES OF EVOLUTION.

ture to which the author of the " History of Creation" devotes page after page.

It is plain, therefore, that in attempting to give any true and complete history of creation, the production and occurrence of these special chemical compounds, and the fact that they are respectively met with among some only of the forms of life, must not be left out of sight, and we propose in these pages to consider how far the arguments put forward by Professor Hseckel and the school to which he belongs satisfactorily account for the existence of these chemical compounds, and how far these " extensions " of Mr. Darwin's views are to be looked upon as of equal value with the position actually taken up, and the views put forward by that great inquirer into the facts which nature presents to us.

In reading the works of Professor Hseckel, or of any of the school of thinkers to which he belongs, we can hardly fail to be struck with the stress which is laid on the simplicity of structure of the lowest forms as compared with the higher forms of life. We are repeatedly told that the lowest forms are mere shapeless homogeneous lumps of the " matter of life," we are shown their extreme simplicity of form in powerful and effective contrast with the complexity of form exhibited by beings higher in the scale, and we are invited to believe that we have here reached something very simple indeed, and which does not require our further attention when we are considering the pi-oblems presented by the variety of the forms of life.

INTRODUCTORY.

The sooner, however, we disabuse ourselves of the notion that these small shapeless lumps of the matter of life are really simple the better. Our author believes them to be so, merely because he has not examined them with sufficient minuteness. This cannot be done by the aid of the microscope, or of any dissecting instruments we are able to construct ; it is necessary here to have recourse to chemistry to ascertain what the real nature of this apparently simple body is, and the results which chemistry gives are surprising indeed.