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CORNELL
UNIVERSITY

LIBRARY

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Cornell University

Library

The original of this book is in
the Cornell University Library.

There are no known copyright restrictions in
the United States on the use of the text.

http://www.archive.org/details/cu31924031257839

LOWEST FORMS OF LIFE.

Organisms Produced within Closed Flasks which had been
- Previously Heated to 270-275° F. for Twenty Minutes, and
to Temperatures over 230°F. for One Hour. (X 800).

See pp. 175-178.

EVOLUTION

AND THE

ORIGIN OF LIFE

BY

-H” CHARLTON BASTIAN, M.A., M.D, F.RS.

Fellow of the Linnean Society,
Fellow of the Royal College of Physicians,
Professor of Pathological Anatomy in University College, London,
Physician to University College Hospital.

London:
MACMILLAN AND CoO.'
1874.

‘To experience we refer, as the only ground of all physical inquiry. But before
experience itself can be used with advantage, there is one preliminary step to make,
which depends wholly on ourselves: it is the absolute dismissal and clearing of the
mind of all prejudice from whatever source arising, and the determination to stand
or fall by the result of a direct appeal to facts in the first instance, and of strict
logical deduction from them afterwards.”

Sir Joun HerscuE.: Discourse on the Study of Natural Philosophy.

“The fair question is, Does the newly proposed view remove more difficulties,
require fewer assumptions, and present more consistency with observed facts than
that which it seeks to supersede? if so the philosopher will adopt it, and the world
will follow the philosopher—after many days.”

Mr. Justice Grove: Jxaugural Address as President of the British
Association, 1866.

PRE ac E,

SINCE the publication of my larger work, “The
Beginnings of Life,” in 1872, some long-overhang-
ing clouds have been dispersed. Well-informed men
of science no longer doubt that swarms of Bacteria
can be made to appear within sealed glass vessels
containing suitable fluids, after the vessels and their
contents have been exposed to the temperature of
boiling water. The thorough establishment of this
fact has been of the greatest importance.
Statements as to the reality of so unexpected
an appearance of Bacteria were previously received
with actual disbelief or the profoundest scepticism.
It was much easier to imagine that I had been
mistaken or deceived than to suppose that living
Bacteria could really appear within closed flasks

which had been subjected to the conditions men-

vi PREFACE.

tioned. This time-serving and popular verdict
once announced, was received with all the more
readiness, because others, not having exercised the
necessary care, had for a time failed to confirm
my results. Now, however, that the facts have
been substantiated and are generally acknow-
ledged, the subsequent course of events has made
it useful to ask, Why the majority of persons com-
petent to judge, previously received the statements
referred to with so much incredulity ?

To this question only one answer can be given.
The results were discredited because it was a
generally accepted belief amongst men of science
that exposure to the temperature of boiling water
would have killed all pre-existing Living Matter
within the flasks. And this being the case, the
appearance of swarms of Bacteria in the experi-
mental fluids in the course of a few days could
only be explained by the supposition that what
has been called ‘Spontaneous Generation’ had
occured. To acknowledge this, however, was rank
heresy, and was in opposition to some of the: most
cherished and sacred beliefs of many men of science.

In such an emergency what were scientific in-

PREFACE. vi

vestigators to do? Should they equivocate and,
without definite trial as to the truth or untruth
of their old belief in the destructive influence
of boiling water, at once cast it aside? This
would certainly seem a strange course to pursue,
seeing that a strong belief iu the lethal effects of
boiling water had been the measure of their
previous profound unbelief of facts now demon-
strated to them! Yet this course was in some
respects the easiest—it would expose those who
followed it to less external friction, and it allowed
them still to hold fast to a long-cherished con-
viction as to the truth of the dogma omne vivum
ex vivo, which they perhaps found it impossible to
throw aside. But whatever extenuating circum-
stances might be pleaded, it cannot be concealed
that the course actually adopted was not the
method by which men of science usually pursue

their investigations.

The question of ‘Spontaneous Generation,’ there-
fore, at present stands in this position. If it be
really true that all known forms of Living Matter

are killed by a brief exposure in the moist state

viii PREFACE.

to the temperature of 212° F., there is no longer
room for doubt. The occurrence of ‘Spontaneous
Generation’ must in this case be admitted as an
established fact, or ‘Law of Nature,’

But the evidence now in our possession concerning
the death-point of heated Living Matter all tends
to show that it is killed at a temperature below
that of boiling water, as will be seen by the facts
recorded in the last essay of this volume. The
two previous papers, moreover, contain the records
of experiments proving that Bacteria and their
germs are killed at 140° F.—these being the very
organisms that most frequently make their appear-
ance in the fluids within closed experimental vessels
which have been previously heated to 212° F.

In the present aspect of the question, therefore,
these three papers contain all the evidence needed
for the establishment of the occurrence of ‘Spon-
taneous Generation.’ In the two parts of the first
essay, however, I have endeavoured to show that
the acknowledgment of this natural origin of Liv-
ing Matter carries with it no contradictions, and is
indeed in accordance with the present state of

scientific knowledge. I have further striven to give,

PREFACE. ix

in brief compass, a synopsis of other evidence in
favour of Archebiosis and Heterogenesis (the two
processes now included under the phrase ‘Spon-
taneous Generation’); to indicate some of the
modifications in biological doctrine which a belief
in the present occurrence of these processes will
necessitate ; and generally to show, to the best of
my ability, the weakness and untenability of the
old view.

In the execution of a task so complicated and
difficult, there must necessarily be many imper-
fections. I am anxious, however, to promote what
I consider to be the cause of truth, and have
therefore collected the papers included in the
present volume, in the hope that they may be of
some little use and interest to those desirous of
obtaining information on the present aspect of the

great questions to which they relate.

QUEEN ANNE STREET, CAVENDISH SQUARE,
October 26th, 1874.

CONTENTS.

I.—THE EvoLuTion HYPOTHESIS AND THE ORIGIN OF LIFE.

PART I.

(From the Contemporary Review of March, 1874, with slight

Alterations and Additions.)
PAGE

Evolution—Its Scope and Meaning—Uniformity of Nature—
Modifications of Doctrine often Incomplete at First—The
Nebular Hypothesis—Original Advent of Living Things
on the Earth—Views of Eminent Evolutionists—Mr.
Darwin—Mr, Herbert Spencer—Mr. G. H. Lewes—
Professor Huxley—A pparent Inconsistencies — Origination
and Growth Compared—These Processes in Crystalline
and in Living Matter respectively -No Reason why Origi-
nation of Living Matter should have Ceased—Professor
Clarke Maxwell on the Persistence of Molecular Properties
—Mr. Spencer’s Assumption—Professor Huxley’s Views
—Their Inconsistencies—Sir Wm. Thomson’s Hypothesis
—Misconceptions concerning Spontaneous Generation—
These not to be Entertained by Evulutionists—Professor
Huxley’s Suppositions concerning the Past—Their Unten-
ability when Judged by his own line of Criticism—Condi-
tions Favouring Growth mostly Favour Origination—
Present Continuance of Archebiosis—Shown by Existence
of the Lowest Organisms—Mr. Spencer’s Mode of dealing
with this Question—His Views on this subject not Recon-
cilable with his Principles of Evolution—Has the Amoeba
a Longer Line of Ancestry than Man? Yes, unless the
Continuance of Archebiosis or Heterogenesis be Conceded. 1-39

xii CONTENTS.

PART IT.

(From the Contemporary Review of April, 1874, with Re-

arrangements and Additions.)
PAGE
Inconsistency of Limiting Archebiosis to the Past—Professor

Huxley’s Inaugural Address—Its Partial Consideration
of the Facts—Refutation of its Principal Positions—Air
does not Swarm with Bacteria Germs—Bacteria will
Appear in Fluids Previously Heated to 212° F.—Yet
Bacteria and other low Organisms are Killed in Fluids
Heated to 140° F.—Professor Huxley’s Action in Face
of New Facts—Behaviour of Other Opponents of Spon-
taneous Generation—Sir John Herschel’s Precepts. . . 43-50

Necessity of Examining the New and the Old Doctrine as
mere Hypotheses—Each Hypothesis Supported by an
Analogical Argument—That in favour of Archebiosis
—Foundations of the Counter Hypothesis—Insufficient
Warrant for the Formula ‘Omne Vivum ex Vivo’—It
affords a Notable Instance of Faulty Induction—Weighty
Considerations in Support of Archebiosis—Heterogenesis
a Necessary Consequence of Archebiosis—Its Occurrence
harmonious with Physical Doctrines of Life—Evidence of
its Occurrence more Varied than for that of Archebiosis—
Detailed Enumeration of Evidence—Panspermism Weak
even as an Hypothesis—Mr. Justice Grove’s Dictum—
Panspermism can be Overthrown by a ‘ Crucial Instance’
—Vacillations and Evasions of some Evolutionists in
Connection with this Part of the Subject—Concurrence
of Testimony as to the Temperature at which Living
Matter is Killed— Establishment of Archebiosis as a Law
of Nature. 2. 6 6 1 ee eee ee eek. 50-69

New Views — Characteristics of Living Matter — Its
Tendency to Organization—Conditions which Faveur it—
Cause of Reproduction — Meaning of Heterogenesis—
Ephemeromorphs — ‘ Alternate Generation’—Origin of
Species—Limitation of Sphere of ‘ Natural Selection ’—

CONTENTS. xiii

PAG
Its Real Influence— Other Causes of Modification — ae

Organic Polarity—Speculative Deductions Concerning
‘Trees of Life’ in the Past ; Concerning the Resemblance
of their Products in Different Ages; Concerning the
greater Extent of this Resemblance amongst the Lowest
Types ; and Concerning the possibility of the Vertebrate
Type having been more than once Attained. . . . . 69-76

IJ..-ON THE TEMPERATURE AT WHICH BACTERIA, VIBRI-
ONES, AND THEIR SUPPOSED GERMS ARE KILLED WHEN
IMMERSED IN FLUIDS Ok ExposeD 'ro HEAT IN A
Moist STATE.

(From the Proceedings of the Royal Society, No. 143, 1873 )

Controversy between the Abbé Spallanzani and Needham—
Spallanzani’s Conclusions—Overthrow of the Aerial-Con-
tamination Doctrines—Professor Huxley’s Criticisms — .
Writers’ Previous Investigations on Vital Resistance of
Bacteria— Method of Experimentation—Applicable for
Invisible Germs and for Parent Organisms—Means for
Lowering Productivity of Organic Fluids—New Inocula-
tion Experinents—Tabular Results—Conclusions as to
Degree of Heat which Destroys Bacteria and their Germs
—Decisive Nature of these Results—Taken in Conjunction
with other Experiments they Establish the Occurrence of
‘Spontaneous Generation’ . 2. 6. 6. ee ee 79-97

JIL.—FuRTHER OBSERVATIONS ON THE TEMPERATURE AT
WHICH BACTEREA, VIBRIONES, AND THEIR SUPPOSED
GERMS ARE KILLED WHEN EXPOSED TO HEAT IN A
Moist STATE; AND ON THE CAUSES OF PUTREFACTION
AND FERMENTATION.

(From the Proceedings of the Royal Socity, No. 145, 1873.)

Different Behaviour of Saline Fluids and Organic Infusions
when Inoculated—Cause of this Difference—Two-fold
Composition of Inoculating Material—Its Living and its
Mere Organic Elements—The Temperature of 140° F,

xiv

CONTENTS.

may De-energize the Former but not the La'ter—Experi-
ments with Infusions of Different Strengths tend to Prove
this—Reasons for Believing the Delayed Putrefaction in
Inoculated Organic Fluids Heated to 140° F. to be due to
the Mere Organic Matter of the Inoculating Medium—
Proof of this—And proof by New Experiments that
Bacteria and their Germs are Killed in Organic Fluids
Heated to140°F. . .

Uniformity of Evidence as to Death-point of Living

Ferments—Important Difference between Living and Not-
Living Ferments as regards their Power of Resisting Heat
—This Point of View Steadfastly Ignored by M. Pasteur
and his Followers—A bsence of all Evidence to Show that
Heat is Less Destructive to Living Matter in Some Fluids
than in Others —M. Pasteur’s Experiments never Distinctly
capable of Supporting such a Conclusion—He Ignored an
Equally Possible though Opposite Interpretation whose
Truth has been now Established .

Inadequacy of M. Pasteur’s ‘ Vital Theory’ of Fermen-

tation—What New Experiments Teach—Three Degrees
of Fermentability — Self-Fermentable Fluids — Tabular
Statement Concerning—Second Degree of Fermentability
—Explanation of M. Pasteur’s Celebrated Experiments in
which he Sowed mere Organic Fragments and called
them ‘Germs’— Explanation of Other Experiments—
Origin of Torula—Meaning of their Appearance—Fer-
mentation may gradually Merge into Putrefaction—Third
or Lowest: Degree of Fermentability—Fluids which only
Change under Influence of Most Potent Ferments (Living
Organisms) — Uniformity of Results in Inoculation Experi-
ments—This Adverse to Explanation of Cases of Delayed
or Smouldering Fermentation by M. Pasteur’s Theory—
Living Ferments Act Promptly and with Regularity
—wNot-living Ferments often Act Slowly and with Great
Irregularity—Results of Several Series of Different Experi-
ments point to Archebiosis as the only Means of Recon-
ciliation—Conclusions. . . .

PAGE

ToOI-112

112-116

116-129

CONTENTS. xv

PAGE
IV.—.THr Destructive INFLUENCE oF HEAT UPON

Livinc Matter.

(From the Contemporary Review of September, 1874, with many
Additions and slight Alterations.)

Effects of Boiling Water on Human Tissues—Its Action upon
Eggs — Importance of Definite Information upon this
Subject—Reluctance of the Modern Panspermatists to
Seek it—Original Investigations by Spallanzani—Reasons
for Referring to them—His Frank Announcement of the
Points in Dispute— Method and Results of his New
i-xperiments— His Conclusions and Reasoning thereon—
His attempt at Reconciliation of Different Experimental
Results—The Assumptions by which alone he could Stave
off a Belief in ‘Spontaneous Generation’. . + 133-155

His Assumptions regarded by the Light of Modern
Science—Bacteria and their Germs not able to Survive
Desiccation—Untenability of Another Assumption on
which he Relied—Reasons for Belief in the Ascertained
Death-Point of Bacteria (140° F.)—Harmonious Results
atrived at by Max Schultze, Kiihne, and others—Evidence
Concerning Organisms in Hot Springs—Unanimity of
Different Observers as to Death-point of Living Matter—

This in Accordance with known Unity of Protoplasm—
Curious Attitude assumed by Opponents of ‘ Spontaneous
Generation’ — Considerations under which they seek
Refuge—The ‘Lump’ Theory and its Explosion—New
Difficulties for Consideration of Opponents—Two Most
Important Experiments—Impossibility of Explaining their
Results except by Archebiosis . . . . 2. 2. 1. . . 155-180

Some Misapprehensions Discussed — Heterogenesis and
what it Means—The Evolutionist Must Distinguish it from
Archebiosis—The Vitalist could not believe in Archebiosis
—The Evolutionist must distinguish between Living and
Dead Organic Matter—Archebiosis may occur amongst
Dead Organic Materialsk—The Term therefore Applicable
to the Process occurring in Ordinary Flask Experiments
and also to the Primordial Origin of Life—The Actual
Process of Growth is as inexplicable as the Process of
Origination . 1. 6 6 6 ee ew ee ee ee 180-186

I.
THE EVOLUTION HYPOTHESIS,

AND THE ORIGIN OF LIFE.

PART L.

YEAR by year the word ‘Evolution’ becomes
diffused more widely through our literature, and
the central idea which it implies grows familiar to
an ever-increasing multitude of readers. We have
witnessed within the last few years a marvellous
awakening of interest in the minds of the public
generally to questions of science, and it so happens
that a discussion of the Doctrine of Evolution has
been more or less directly involved in those depart-
ments of Science and Philosophy which have during
this period received the largest share of popular
attention.

Perhaps the greatest impetus was given to the
spread of the doctrine about fourteen years ago,
by the publication of Mr. Darwin’s now celebrated
“Origin of Species.” This volume has been followed
by quite a library of works and memoirs on the
same subject—partly scientific and partly popular.
From about the same date also, Mr. Herbert Spencer
has been engaged in systematically elaborating the

B2

4 EVOLUTION AND THE

principles of an all-comprehensive Evolution Phi-
losophy, and the results of his genius and labour
are now undoubtedly influencing the thoughts of a
rapidly widening circle of readers. Both in this
country and abroad the doctrine of Evolution is
gradually but surely gaining ground amongst the
most reflective, and although many other writers
have been more ‘or less influential in determining
this result, it has been in the main brought about by
the two above mentioned.

Evolution implies continuity and uniformity. It
teaches us to look upon events of all kinds as the
products of continuously operating causes—it recog-
nises no sudden breaks or causeless stoppages in
the sequence of natural phenomena. It equally
implies that natural events do not vary sponta-_
neously. It is a philosophy which deals with
natural phenomena in their widest sense: it em-
braces both the present and the far-distant past.
It seeks to assure us that the properties and
tendencies now manifest in our surrounding world
of things, are in all respects similar to those which
have existed in the past. Without: a basis of this
kind, the Evolution Hypothesis would be a mere
idle dream. Uniformity is for it an all-pervading
necessity. - Starting from facts of daily observation
and from scientific experiments, the properties and:

ORIGIN OF LIFE. 5

tendencies of things are noted and grouped ; whilst
philosophers, using the knowledge thus gained, seek
to trace back the progress of events and show how
this complex world has gradually been derived from
a world of more and more simple composition. We
are taken back in imagination even much further.
We are referred to a primal haze or nebula—as the
gigantic germ of a future Universe. This was the
conception of Kant and of Laplace.

But whether we follow the philosopher in his bold
speculations concerning the past, or listen to the
biologist making his predictions as to the future
stages which the germ of a given animal will pass
through in the progress of its evolution—in each case
the ‘uniformity of nature’ is tacitly assumed. This
assumption underlies almost all our thoughts and
actions, even in every-day life. And without such a
belief regarding the succession of events science would
be impossible—the very idea of it, in fact, could never
have arisen. In its absence we could neither fathom
the past nor illumine the future. As Mr. Mill said,*—-
“Were we to suppose (what it is perfectly possible to
imagine) that the present order of the universe were
brought to an end, and that a chaos succeeded in
which there was no fixed succession of events, and
the past gave no assurance of the future, if a human

* Syst. of Logic, 6th edit. vol. ii. p. 98.

6 EVOLUTION AND THE

being were miraculously kept alive to witness this
change, he surely would soon cease to believe in any
uniformity, the uniformity itself no longer existing.”

It is true that in earlier times no absolute belief in
the uniformity of nature existed, even amongst the
select few. The Greek philosophers, including Aris-
totle, recognised ‘chance’ and ‘spontaneity’ as find-"
ing a definite place in Nature, and to this extent they
were not sure that the future would resemble the past.
But as we have become more familiar with a wider
range of natural phenomena and with their mutual
relations or order of appearance, so has the conception
of chance or spontaneity disappeared from the scien-
tific horizon—driven out of the field by the steady
advance of Law and Order. Those who embrace the
Evolution Philosophy are foremost in this opinion—
they believe that no effects of whatsoever kind can
occur without adequate causes, and, the conditions
being similar, that the same results will alway follow
the action of any given cause. Their whole creed is,
in fact, pre-eminently based upon an assumed Uni-
formity of Nature.

he present is essentially a time of transition in.
matters of opinion. Men who have been educated in.
one system of scientific beliefs are gradually being
converted to another, because the new system is

ORIGIN OF LIFE. 7

thought to be more harmonious with the observed
order of natural phenomena. This has been the case
even with our chief exponents of Evolution. They
have themselves had to unlearn much which they had
previously learned. The doctrine of Evolution has
thus been developed only by the sacrifice of many
previous early beliefs and modes of thought. But it
often happens that an old belief will—unknown per-
haps to the person himself—leave decided traces of
its previous influence, and thus prevent for a time the
full realization or adoption of all the logical conse-
quences of new views. This vestige of the old state
of opinion or habit of thought is more especially apt
to remain in directions where unexplained facts still
_exist and strong prepossessions or prejudices bar the
way. Some modes of this half-unconscious inconsist-
ency may become obvious to one worker or thinker,
and some to another, according to the particular
direction which his investigations or thoughts may
have taken; and if they are of an important nature
such inconsistencies should be pointed out from time
to time. With the view, therefore, of strengthening
an hypothesis which I, in common with so many
other workers in science, believe to be true, I now
venture to allude to certain apparent anomalies in the
declared opinions of the most prominent upholders of
the doctrine of Evolution in this country. It seems

8 EVOLUTION AND THE

all the more desirable that this should be done,
since the inconsistencies may be easily shown to be
wholly uncalled for, and to involve sundry unscientific
conceptions. Yet the modifications of opinion which
appear to be demanded—on the ground of fact as well
as on the ground of reason—will necessitate very con-
siderable and almost revolutionary changes in the
accepted code of biological doctrines.

An examination of the facts of science generally
and of various every-day phenomena, teaches us,
according to the Evolutionist, that Matter of different
kinds, situated as it is and has been, gradually tends
within certain limits to become more and more
complex in its internal and external constitution.
Coupling this conclusion with various astronomical
data, with geological data, and with facts derived
from the study of the past forms of Life upon our
globe, the Evolutionist essays to penetrate through
the long vista of bygone ages, till he may rest his
speculative gaze upon a vast rotating nebular mass
of gaseous matter of comparatively simple though
unknown constitution, from which he supposes our
Universe to have been slowly evolved. Without futile
questionings as to the explanation or cause of the
existence of the Nebula—without speculation as to
what simpler or more complex matter may have
immediately preceded it—it is obvious that we may

ORIGIN OF LIFE, 9

for our own convenience direct our attention espe-
cially to any particular stage of its hypothetical
- existence. At the same time we must be equally
free to admit that, in concentrating our attention
upon the nebular stage, or upon any other, we arbi-
trarily break into a mysterious cycle of existence
whose Cause is to us unfathomable. It is needless
for my purpose, however, to attempt to concentrate
the reader’s attention upon a period so remote in the
history of our Universe. We are led to believe that
the primordial nebula. as it cooled and condensed
acquired a more rapid axial rotation; that masses
were. gradually thrown off from its circumference ;
and that these in their turn condensed into rotating
spheroids, which continued to circulate round the
parent mass in elliptical orbits. Assuming, then,
with the Evolutionist, that our own planet had a past
history of this kind, we must also assume that it
gradually changed from a gaseous to a fluid state
before beginning to solidify by the formation of a
superficial crust—a crust which gradually thickened
as the fervent heat of it and of the fluid nucleus
abated by heat radiations into space. Until this
stage of the Earth’s history had been far advanced,
no Living Things could have existed upon its surface.
“Hence,” as Sir William Thomson said,* “when

* Inaugural Address at Meeting of British Association, /Vadure,
Aug. 3, 1871, p. 269.

Io EVOLUTION AND THE

the Earth was first fit for life there were no living
things on it. There were rocks, solid and disintegrated,
water, air all round, warmed and illuminated by a
brilliant sun, ready to become a garden.” Living
things must, however, have appeared upon its surface
at some very remote epoch, since their remains are
to be found far down in the rocks which at present
constitute its crust. How, therefore, it may be asked,
is the first appearance of ‘Living matter’ upon the
earth to be accounted for?

We should not needlessly invoke an unknown act
of Creative Power—we must not, even with Sir
William Thomson, resort to the strange notion of an
importation of living germs upon a “ moss-grown
fragment from the ruins of another world,” unless
more ordinary natural causes fail and it be found really
necessary to invent some such hypothesis—and the
necessity here could never be shown since:Sir W.
Thomson’s hypothesis shirks the question of the Origin
of Life so far as our earth is concerned, and merely
hands it over as an unsolved problem to the denizens
of another sphere. Now, the thoroughgoing Evolu-
tionist repudiates the notion of Creation in its ordi-
nary sense ; he believes that the operation of natural
causes, working in their accustomed manner, were
alone quite adequate to bring into existence a kind
of matter presenting a new order of complexity, and

ORIGIN OF LIFE. II

displaying the phenomena which we have generalised
under the word ‘Life.’ Living matter is thus sup-
posed to have come into being by the further opera-
tion under new conditions of the same agencies as
had . previously led to the formation of the various
inorganic constituents of the Earth’s crust—such
mineral and saline substances as we see around us
at the present day. What we ‘all ‘Life,’ then, is
regarded as one of the natural results under actual
conditions of the growing complexity of our primal
nebula. So that, in accordance with this view, we
have no more reason to postulate a miraculous inter-
ference or exercise of Creative Power to account for
the evolution of ‘living matter’ in any suitable por-
tion of the Universe (whether it be on this Earth or
elsewhere), than to explain the appearance of any
other kind of matter—the magnetic oxide of iron,
for instance. So far, all through Evolutionists are
quite agreed. This is the view of Spencer, Lewes,
Huxley, and others—possibly of Darwin. I say
possibly of Darwin, because on this subject it so
happens that the language of this most distinguished
exponent of Evolution is quite unusually tinctured
with a previous point of view. Speaking of the
probable commencement of Life upon our globe,
Mr. Darwin says*:—“TI believe that animals have

* Origin of Species, 6th edit. 1872, pp. 424 and 429.

12 EVOLUTION AND THE

descended from at most only four or five progenitors,
and plants from an equal or lesser number. Analogy
would lead me one step further, namely, to the
belief that all animals and plants have descended
from some one prototype.. . . There is grandeur
in this view of life, with its several powers, having
been originally breathed by the Creator into a few
forms, or into one; and that whilst this planet has
gone cycling on according to the fixed law of gravity,
from so simple a beginning endless forms, most
beautiful and most wonderful, have been and are
being evolved.” Taking into account the phraseology
made use of in the above quotation, we have little
difficulty in recognising the views of an Evolutionist,
dwarfed and modified tnough they are by an _ ulti-
mate appeal to a Creative act only a little less
miraculous and singular than the mythical origin of
our reputed ancestors— Adam and Eve. Some exist-
ing naturalists may perhaps contend that Mr. Darwin
ought to have kept more closely to the Mosaic record
—replacing his one primordial form by a dual birth
of male and female, without whose mutual influence
no “biological individuals” can in their opinion
come into existence. Such a supposition, it is true,
would be as antiquated and unnecessary from the
Evolutionist’s point of view as is the whole notion
of life having been originally “breathed” into one

ORIGIN OF LIFE. 13

or more organic forms. Mr. Spencer’s language is
happily free from both these defects: he neither uses
the phraseology of the Creative Hypothesis, nor does
he adopt a definition of biological “individuality ”
at variance with the Evolution Philosophy. He
distinctly teaches that living matter must have been
at first formless, and that multiplication would have
taken place, as amongst the lowest living units of
the present day, exclusively by agamic methods—
nay, more, he teaches that living matter must have
been the gradual product or outcome of antecedent
material combinations. “Construed in terms of evo-
lution,” he says,* “every kind of being is conceived
as a product of modifications wrought by insensible
gradations on a pre-existing kind of being, and this
holds fully of the supposed ‘commencements of
organic life,’ as of all subsequent developments of
organic life.”

But on the question whether the process of Arche-
biosis (life-evolution) is likely to have occurred once
only, as Mr. Darwin seems to hint, or in multitudinous
centres scattered over the earth’s surface, Mr. Spencer
makes no definite statement. The latter belief would,
however, be entirely in accordance with his general
doctrine ; and we seem all the more entitled to infer
that Mr. Spencer inclines to the notion of a multiple

* Principles of Biology, vol. ii, Appendix, p. 482.

14 EVOLUTION AND THE

occurrence of Archebiosis, both in space and in time,
since he does not reject the possibility of its occur-
rence in our own day. Granting “that the formation
of organic matter and the evolution of life in its
lowest forms may go on under existing cosmical con-
ditions,” he believes it “more likely that the formation
of such matter and of such forms took place at a
time when the heat of the earth’s surface was falling
through those ranges of temperature at which the
higher organic compounds are unstable.” But con.
clusions which we are only able to infer from the
writings of Mr. Spencer have been distinctly enun-
ciated by Mr. G. H. Lewes. In a criticism of the
“Darwinian Hypotheses,” he very forcibly pointed
out that it is quite compatible with the hypothesis
cf evolution to admit a variety of starting points for
the formation of living matter, and he consequently
laid down in principle a very important extension of
the Darwinian doctrine, in its application to higher
organisms. He said:* “Although observation re-
veals that the bond of kinship does really unite many
divergent forms, and the principle of Descent with
Natural Selection will account for many of the re-
semblances and differences, there is at present no

warrant for assuming that all resemblances and

* Fortnightly Review, 1868.

ORIGIN OF LIFE. 15

differences are due to this one cause, but, on the
contrary, we are justified in assuming a deeper prin-
ciple which may be thus formulated: All the complex
organisms are evolved from organisms less complex,
as these were evolved from simpler forms: the link
which unites all organisms is not always the common
bond of heritage, but the uniformity of organic laws
acting under uniform conditions. . . . It is there-
fore consistent with the hypothesis of Evolution to
admit a variety of origins or starting points.” In
this paper Mr. Lewes distinctly postulates the prob-
ability of a repetition of the process of Archebiosis,
wherever the conditions were favourable, and though
he says nothing against the continuance of such a
process in the present day, neither does he dwell
upon it as a probability.

Professor Huxley’s* opinions on the subject of
Archebiosis are very similar to those of Mr. Spencer}
with the exception that he seems more strongly
opposed to the notion of its occurrence at the present
day, and it is to this aspect of the question that I
would now direct the reader's attention. Why should
“men of such acknowledged eminence in matters of
Philosophy and Science as Mr. Herbert Spencer and
Professor Huxley promulgate a notion which seems

* Inaugural Address at Meeting of British Association, WVature,
Sept. 15, 1870, Pp. 404.

16 EVOLUTION AND THE

to involve an arbitrary infringement of the Uniformity
of Nature?

They would both have us believe that living matter
came into being by the operation of natural causes—
that is, by the unhindered play of natural affinities
operating in and upon matter which had already
acquired a certain degree of molecular complexity.
They believe that the simpler kinds of mineral and
crystalline matter continue to come into being now
as they have ever done; nay, more, they believe
that the higher kind of matter, originally initiated
by the operation of natural causes, continues to ‘grow’
both in animal and in vegetal forms, solely under
similar influences, and yet they consider themselves
justified in supposing that natural causes are now
no longer able independently to initiate this living
matter or protoplasm. Again, we find Professor
Tyndall* also affirming, in the most unhesitating
language, the ultimate similarity between crystalline
and living matter: affirming that all the various

_ structures by which the two kinds of matter may be
represented are equally the “ results of the free play
i of the forces of the atoms and molecules” entering
into their composition. And yet he, too, would have
us believe that whilst differences in degree of mole-
cular complexity alone separate living from not-living

* Fragments of Science, qth edit. (1872), pp. 85—87, and 113—119.

ORIGIN OF LIFE. 17

matter, the physical agencies which freely occasion
the growth of living matter are now incapable of

causing its origination.

Why, we may fairly ask, should a supposed differ-
ence be erected by Evolutionists between Origination
and Growth in the case of living matter, whilst no
one -dreams of making any such distinction in refer-
ence to crystalline matter? Is it true that the
process of growth differs from the process of origi-
nation, and, if so, in what respects? Philosophically
speaking there is little difference. Take the case of
the formation of the “silver tree” cited by Professor
Tyndall. A weak galvanic current is passed through
a solution of nitrate of silver, and simultaneously in
a first increment of time a number of molecules of
oxygen and of silver begin to aggregate independently
into crystals of oxide of silver ; in a second increment
of time the operation of the same causes~ produces
similar results, only now part of the new crystalline
matter forms in connection with the existing recently-
formed germs of crystals, though part of it may still
aggregate independently. During a third, a fourth,
and all succeeding increments of time in which the
same causes operate amidst similar conditions, similar
results must ensue. But, taking the process of origi-

nation that occurs in the first increment of time,
c

18 EVOLUTION AND THE

would Professor Tyndall have us believe that it is
in any essential way different from that process of
growth which may take place in a second, third, or
fourth increment of time? Does not the very fact
that origination and growth so often occur simulta-
neously in the case of crystalline matter, and under
the influence of the same causes, show us that the
two processes are intrinsically similar, and that con-
ditions favourable for growth are also likely to be
favourable for origination? And if this be true for
crystalline matter, may we not infer that it would
also be true for living matter? These are questions
neither asked nor answered in any definite manner
by those whose opinions I have already cited. They
are, however, questions by no means unworthy of an
attentive consideration.

Although, as a general rule, conditions favourable
for the growth of any particular kind of crystalline
matter are likely to be favourable for its origination,
still it must be acknowledged that the presence of
a crystal will occasionally lead to its growth in a
medium in which similar crystalline matter had
previously shown no tendency to form independently
—even in cases where the introduction of a non-
crystalline nucleus would not be able to determine
a similar formation of crystalline matter. Notwith-
standing the general law, ,therefore, that conditions

‘ORIGIN OF LIFE. 19

favourable for the growth are also favourable for
the origination of crystalline matter, we are com-
pelled to admit that growth may be determined
under certain conditions where origination does not
occur, and that the presence of pre-existing crystalline
matter favours the process. And a distinction of
the same kind undoubtedly obtains in the case of
living matter. We know quite positively that
although Bacteria will not originate in a previously-
boiled ammonic tartrate solution, or ‘ Pasteur’s
solution, that the addition of a few of these
organisms (all other conditions remaining the same)
to either one of the solutions will soon occasion a very
considerable growth of the living matter of which
Bacteria are composed.* Weare thus reduced to ask,
whether the influence of the pre-existing nucleus is
relatively more potent or more necessary in the
case of living matter than it is in the case
of crystalline matter? And this is a question which
unfortunately we are unable definitely to answer:
such minute quantitative and qualitative distinctions
cannot be made. But so long as we have no positive
knowledge on this subject, we surely have little
right to infer that processes both of origination and
of growth continue in the case of crystalline matter,
and that the process of growth alone survives in the

* The Beginnings of Life, vol. i. p. 325.

20 EVOLUTION AND THE

case of living matter. There are no facts easily
discoverable upon which such a fundamental assump-
tion can be legitimately based — for it is one
which the Evolutionist should not admit except upon
evidence of the clearest and most unambiguous
nature.

The probabilities would certainly seem to be alto-
gether in favour of the continuance of a natural
process like Archebiosis after it had been once
initiated, more especially when this natural process
is so closely allied to another (namely, the ‘growth’ of
living matter) which manifests itself with the utmost
readiness on all parts of the earth’s surface. So
that unless very cogent reasons can be adduced
against the occurrence of Archebiosis at the present
day, looked at from an @ priori point of view, there
would seem scarcely room for doubt upon the
subject. The properties and chemical tendencies of
material bodies appear to be quite constant through
both time and space. Speaking upon this subject
in a recent discourse on ‘Molecules,’ Professor
Clerk Maxwell says,* “We can procure specimens
of oxygen from very different sources, from the
air, from water, from rocks of every geological
epoch. The history of these specimens has been
very different, and if, during thousands of years,

* Nature, Sep. 25, 1873, p. 440.

ORIGIN OF LIFE. 21

difference of circumstances could produce difference
of properties, these specimens of oxygen would
show it. . . . In like manner, we may procure
hydrogen from water, from coal, or, as Graham
did, from meteoric iron. Take two litres of any
specimen of hydrogen, it will combine with exactly
one litre of any specimen of oxygen, and will
form exactly two litres of the vapour of water.

Now, if during the whole previous history
of either specimen, whether imprisoned in the rocks
flowing in the sea, or careering through unknown
regions with the meteorites, any modification of
the molecules had taken place, these relations
would no longer be preserved. . . . But we have
another, and an entirely different method of com-
paring the properties of molecules. The molecule,
though indestructible, is not a hard rigid body, but
is capable of internal movements, and when these
are excited it emits rays, the wave-length of which
is a measure of the time of vibration of the mole-
cule. . . . By means of the spectroscope the
wave-lengths of different kinds of light may be
compared to within one ten-thousandth part. In
this way it has been ascertained, not only that
molecules taken from every specimen of hydrogen
in our laboratories, have the same set of periods
of vibration, but that light having the same set of

22 EVOLUTION AND THE

periods of vibration, is emitted from the sun and
from the fixed stars. . . . We are thus assured
that molecules of the same nature as those of our
hydrogen exist in those distant regions, or at least
did exist when the light by which we see them was
emitted.” With evidence such as this before us,
which could be multiplied to an enormous extent,
we should hesitate before needlessly postulating
any infringement of the uniformity of natural
phenomena: we ought in fact only to entertain
such a supposition when it has been lightly forced
upon us. Certainly we should not resort to it
and then strain the interpretation of natural and
experimental phenomena into a forced accord-
ance.

What, then, are the reasons assigned for. the non-
occurrence at the present day of the process of
Archebiosis? All that Mr. Spencer says upon the
subject is, that such a process seems to him more
likely to have occurred at “a time when the heat
of the earth’s surface was falling through those ranges
of temperature at which the higher organic com-
pounds are unstable,” than at the present day. Why
such conditions would be more favourable than
those now existing Mr. Spencer does not say; and
that such an alteration should suffice to put a stop
to Archebiosis, although we see living matter still

ORIGIN OF LIFE. 23

growing freely all. over the earth under the most
diverse conditions as regards temperature, seems
very difficult to believe. Yet no other suggestion
is offered in explanation of an assumption which
seems essentially unscientific. For the assumption
that Archebiosis took place only in the remote
past puts this process on a gas? miraculous level,
and tends to assimilate it to an act of special
creation, the very notion of which Mr. Spencer, in
other cases, resolutely rejects.

Again, what reason does Professor Huxley give, in
explanation of his supposition as to the present non-
‘occurrence of Archebiosis? He says,* if it were given
to him “to look beyond the abyss of geologically re-
corded time” to a still more remote period of the
earth’s history, he would expect “to be a witness to
the evolution of living protoplasm from not-living
matter.” And the only reason distinctly implied why
a similar process should not occur at the present day,
is because the physical and chemical conditions of the
earth’s surface were different in the past from what
they are now. And yet, concerning the exact nature
of these differences, or the degree in which the dif-
ferent sets of conditions would respectively favour the
occurrence or arrest of an evolution of living matter,
Professor Huxley cannot possess even the vaguest

* Nature, Sep. 15, 1870, p. 404.

24 EVOLUTION AND THE

knowledge. He chooses to assume that the unknown
conditions existing in the past were more favourable
to Archebiosis than those now in operation. This,
however, is a mere assumption which may be entirely
opposed to the facts. It is useless of course to argue
upon such a subject, but still it might fairly be said,
in opposition to his view of the impotency of
present telluric conditions, that the abundance of dead
organic mattey now existing in a state of solution
would seem to afford a much more easy starting-point
for life-evolution than could haveexisted in that remote
past, when no living matter had previously been formed,
and consequently when no dead organic matter thence
derived could have been diffused over the earth’s
, surface.*

Professor Huxley is, however, very inconsistent,
since, in spite of his declared expectation of witnessing
the evolution of living from lifeless matter, if it were
given him “to look beyond the abyss of geologically
recorded time,” he had said scarcely five minutes be-
fore, in reference to experimental evidence bearing
upon the present occurrence of a similar process, that
“Gf, in the present state of Science, the alternative is
offered us, either germs can stand a greater heat than

* This is a consideration of great importance; since those who believe
that Archebiosis occurs in organic solutions at the present day, have not
yet professed to show that it can occur in saline solutions free from all
traces of organic matter.

ORIGIN OF LIFE. 25

has been supposed, or the molecules of dead matter,
for no valid or intelligible reason that is assigned, are
able to re-arrange themselves into living bodies, exactly
such as can be demonstrated to be frequently produced
in another way, I cannot understand how choice can be,
even for a moment, doubtful.” Having thus expressed
himself, it was a little strange that Professor Huxley
almost immediately afterwards forgot to inform his
audience what “valid or intelligible reason” he was
able to assign for the occurrence of that evolution of
not-living matter into living protoplasm, in the remote
past to which he alluded. A supernatural interposi-
tion of creative power would explain the presence of
living things upon our earth, just as easily as a super-
natural preservation of living matter from the destruc-
tive effects of heat would account for the presence of
living organisms within certain experimental flasks.
But Professor Huxley most inconsistently says that
even in the face of scientific evidence concerning the
destructive powers of heat upon living matter, he would
rather explain the presence of organisms in certain
flasks on the hypothesis of a (supernatural) preserva-
tion of germs, than believe in the otherwise proved
occurrence of a present life-evolution similar to that
which he assumes to have taken place in the past. He
is willing to accept the supernatural in the present,
though he declines to interpret the past by its aid. He

26 EVOLUTION AND THE

assumes this attitude because no “ valid or intelligible
reason” is assigned in explanation of life-evolution, a
belief in which would render unnecessary any appeal
to the supernatural in the present ; though he himself
postulates the occurrence of the same unexplained
process in the past solely in order to avoid having
recourse to the supernatural. Professor Huxley’s
position in reference to this question is very puzzling,
and one cannot help wondering through what mono-
chromatic glass he had been taking his observations
(from his watch-tower) in order to come to the con-
clusion that “the present state of science” gives any
sanction to such vacillations, or entitles him to appeal
to a supernatural preservation of germs instead of
trusting to the known uniformity of natural pheno-
mena.

Sir William Thomson was certainly much more
consistent. He too seemed inclined to explain the
experiments of our own day by resorting to the hypo-
thesis of a supernatural preservation of germs, and
similarly he seems not unwilling to explain the original
advent of Life upon this globe, by another assumed
process of “contagion.” He has resort neither to a
creative hypothesis, nor to the hypothesis of a natural
becoming of living matter, but, shelving the question
of “origin” altogether, he suggests that our Earth
may have become peopled with organic forms owing

ORIGIN OF LIFE. 27

to the advent upon it, in the remote past, of a “moss-
grown fragment from the ruins of another world.” Sir
William Thomson’s hypothesis seems strangely im-
probable in itself, though it has, in comparison with
the views of other distinguished authorities, the some-
what rare merit of being not inconsistent with his
notions concerning the experiments of to-day. He
does not reject the supernatural in the past, whilst
resorting to it for the present—he resorts to it in the
present and in the past alike, and curiously evades
altogether the real problem as to the Origin of Life.
Since so little—or rather nothing—is said by Pro-
fessor Huxley in support of his supposition that
living matter does not originate in the present day,
even though the process of origination is so closely
akin to that of growth, and though the process of
growth is taking place at every moment of our lives,
in every region of the globe, and under the most
varied conditions—amidst tropical heat and icy cold-
ness, on mountain-tops and deep down in almost un-
fathomable ocean-beds,—it seems only reasonable to
suppose that he must have been influenced by some
strong prepossessions. And so far as one can gather
from his Presidential Address before the British As-
sociation, from which I have already quoted, he does
appear to have been powerfully biased by theoretical
considerations. One of these we shall now consider.

28 EVOLUTION AND THE

Much stress is laid by certain writers upon the fact
that “the doctrine of spontaneous or equivocal gene-
ration has been chased successively to lower and
lower stations in the world of organized beings as
our means of investigation have improved.”* So
that, as another very eminent writer says, “if some
apparent exceptions still exist they are of the lowest
and simplest forms.” And it is usually inferred
from this fact that further knowledge and improved
means of observation will prove these apparent ex-
ceptions to be no exceptions to the supposed general
rule—ommne vivum ex vivo. A consideration of this
kind seems to have powerfully influenced Professor
Huxley.

Much confusion exists in reference to this point,
which needs to be removed. In the first place, it
must be freely admitted that many ancient notions,
dating from the time of Aristotle, on the subject of
“Equivocal or Spontaneous Generation,” as a mode
of origin for large and complex organisms, were
altogether crude and absurd. Secondly, it is neces-
sary to distinguish (and Professor Huxley did so)
between two meanings of the phrase which have
often been confounded with one another—viz., be-

* Prof. Lister, Introductory Lecture (University of Edinburgh),
1869, p. 12. .

+ Mr. Justice Grove (Presidential Address), Rep. of Brit. Assoc. for
the Advancement of Science, 1866, p. 71.

ORIGIN OF LIFE. 29

tween Heterogenesis, or the mere allotropic modifi-

cation of already existing living matter, and Arche- \
biosis, or the independent origination of living matter. {
Thirdly, it should be distinctly understood that

those who strictly adhere to the Evolution Hypothesis

could never believe in the origination of any but the

‘lowest and simplest” organic forms by a process of

Archebiosis. So that the gradual driving of the

question back as one possibly applicable to such

organisms only, is just what the Evolutionist would

have expected, and therefore the objection above

indicated should have been quite pointless for Pro-

fessor Huxley.

Molecular combinations giving rise to units of pro-
toplasm far below the mzndmum visibile stage of our
most powerful microscope, would represent those ini-
tial collocations by which alone living matter could
come into being—though the invisible ‘germs’ thus
initiated may afterwards appear as minutest visible
specks which grow into Bacteria, Vibriones, or Torulz.
We may, therefore, be further permitted to remark
that even if it were given to Professor Huxley to
“look beyond the abyss of geologically recorded
time,” he would be extremely unlikely to witness an
“evolution of living protoplasm from not-living mat-
ter.” At the most, he might see (that is, if equipped
with a powerful microscope) only what he may

30 EVOLUTION AND THE

equally well see now—viz., a gradual emergence into
the sphere of the visible of minute specks of living
protoplasm. But though #e might, when looking
back to this remote age, be inclined to consider such
appearances as testifying to the evolution of living
protoplasm from not-living matter, he would per-
chance find it just as difficult to convince others of
the absence of invisible salamandrine germs (derived
perhaps from the “moss-grown fragment of another
world”) as he is himself difficult to be convinced by
similar appearances at the present. day. Professor
Huxley appears, for the time, to have lost sight of a
consideration justly deemed by Professor Tyndall to
be of great importance in the interpretation of evo-
lutional phenomena—viz., the enormous difference in
point of size between the first constituent molecules
of protoplasm and the minutest visible organisms.
As Professor Tyndall* puts it, compared with their
constituent elements, “the smallest vibrios and bac-
teria of the microscopic field are as behemoth and
leviathan”—even though the latter are often less
‘than soéo0 Of an inch in diameter. How then could
Professor Huxley expect that he might be able to
witness those initial combinations which may never be
seen by mortal eye? All that he might have seen

* Fragments of Science, 4th edit. (1872), p. 151.

ORIGIN OF LIFE. 31

then he can see now—however much this may fall
short of his declared expectation.

Thus it would appear that a consistent belief in the
Evolution Hypothesis almost necessarily carries with
it a belief in the continuance of the process of Arche-
biosis from the remote epoch when living matter first

; appeared upon this earth down to the present time.
The Evolutionist teaches us that living matter is not
in its essence different from other kinds of matter,
and that it originally came into being, like the
\various forms of mineral and crystalline matter, by
the operation of mere natural causes. As Professor
Huxley says:—* “Carbon, hydrogen, oxygen, and
nitrogen are all lifeless bodies. Of these carbon and
oxygen unite in certain proportions and under certain
conditions to give rise to carbonic acid; hydrogen
and oxygen produce water; nitrogen and hydrogen
give rise to ammonia. These new compounds, like
the elementary bodies of which they are composed,
are lifeless). But when they are brought together
under certain conditions, they'give rise to the still
more complex body, protoplasm; and this proto-
plasm exhibits the phenomena of life” Again we
know that the properties and chemical tendencies of
compounds and elementary substances are the same
* Fortnightly Review, Feb. 1869.

32 EVOLUTION AND THE

now as they have been in past ages. So that if living
matter has once arisen naturally and independently,
and if it still continues to “grow” freely under the
most varied conditions upon and beneath the Earth’s
surface, the laws of uniformity alone, upon which all
Science is based, should lead us to expect that it
would continue to have a similar independent ‘ origin.’
These conditions being fulfilled, we have, there-
fore, the best possible @ przort warrant for the belief
that living matter is continually coming into being
by virtue of the operation of the same ‘laws’ or
molecular properties as suffice to regulate its growth.

Let the Evolutionist attempt to deny it, and see
what other difficulties and contradictions he plunges
into, in addition to that lack of consistency which
I have already pointed out.

If an evolution of living matter occurred only far
back beyond the depths of geologically recorded time,
and if, as Mr. Darwin* would have us believe, “all
the living forms of life are the lineal descendants of
those which lived long before the Cambrian epoch,”
how is the Evolutionist to explain the existence of the
multitudinous myriads of lowest and almost structure-
less organisms which exist at the present day? He
starts in his argument in favour of Evolution from the
fact that the condition of homogeneity is one of neces-

* Origin of Species, 6th edit. p, 428.

ORIGIN OF LIFE. 33

sarily unstable equilibrium. All homogeneous matter
inevitably tends to become more or less heterogeneous,
and, of the different kinds of matter, none unites within
itself the various qualities tending to favour this pas-
sage from the homogeneous to the heterogeneous in
the same degree as living matter. These tendencies
are daily exemplified to us by the phases of embryonic
development passed through by the more or less homo-
geneous germs of multitudinous complex organisms.
The embryonic development of one of the higher ani-
mals—of man himself for instance—is a kind of highly
condensed epitome of animal evolution in general.
And the varied forms of life of higher organization,
both animal and vegetal, which have existed, and still
exist, upon the surface of our earth, are all supposed
by the Evolutionist to have arisen by dint of insensible
modifications wrought through the long lapse of ages
upon successive generations of organic forms. But if
living matter, situated as it is and has been, contains
within itself the potentiality of undergoing such mighty
changes and of ever growing in complexity—if from
originally structureless protoplasm (that is, structure-
less to our senses) all the varied forms of life have been
derived, how is it that some of this very same matter
should have remained through the long lapse of ages
almost in its primitive structureless condition? Why

should one portion of the living matter which came
D

34 EVOLUTION AND THE

into being in pre-Cambrian epochs have (in its succes-
sive developments) passed through such marvellous
changes, whilst another portion has continued to grow
—through all the inconceivably numerous generations
that must have occurred between that time and the
present—without undergoing change ?*

What, then, is the meaning of the existence of
Bacteria, Torule, Amcebe, and such simplest organ-
isms at the present day? Mr. Spencer saw the diffi-
culty above indicated, but apparently did not fully
realize its force. He attempted (very inconsistently,
as it appears to me) to meet it by supposing that
living matter may escape increasing organisation so
long as it can avoid the influence of gross changes in
‘external conditions’; and, just as inconsistently, he
assumed that living matter could actually escape
these changes in external conditions through that long
lapse of ages which the lowest estimate regards as a
period of no less than 100,000,000 of years. Speaking

* The multiplication of the lowest forms of life takes place so simply
that, as Prof. Huxley has pointed out, it is nothing more than a process
of ‘discontinuous growth.’ But that such similarity as is above in-
dicated should exist between the structureless units of living matter ot
the present day and those of a remote past, if we have to do merely

' with direct descent or kinship, is regarded as highly improbable by Mr.
/ Darwin, who says:—‘‘ Judging from the past, we may safely infer that
“ not one living species will transmit its unaltered likeness to a distant

futurity.”—Origin of Species, (1872) 6th edit. p. 428,

ORIGIN OF LIFE, 35

of what he presumes to be ancient though almost
structureless kinds of organisms, and endeavouring
to account for their stationary condition as regards
structure by supposing that they have succeeded
through long ages in what I may perhaps be allowed
to call ‘dodging’ all changes in their environment,
Mr. Spencer says:—‘New influences are escaped
by the survival of species in the unchanged parts
of their habitats, or by their spread into neighbour-
. ing habitats, which the change has rendered like their
original habitats, or by both.”

Now, in opposition to both these views of Mr.
Spencer, many very cogent objections may be alleged.
In the first place, in supposing that the organization

-of living matter would not increase even through ages
of time unless it were subject to marked variations in
external conditions, Mr. Spencer makes a supposition
which seems notably at variance with his own doctrines
of Evolution. Does he not for a time ignore those
internal causes of change which must ever be in
operation within living matter as within all other kinds
of matter—and which, even in combination with ap-
proximately fixed external conditions, should suffice
to produce a continually-increasing differentiation
(organization) in living matter? Mr, Spencer himself
says* :—“ All finite forms of the homogeneous—all

* First Principles, 2nd edit. pp. 429 and 548.
D 2

36 EVOLUTION AND THE

forms of it which we can know or conceive—must in-
evitably lapse into heterogeneity. In three several
ways does the persistence of force necessitate this,
Setting external agencies aside, each unit of a homo-
geneous whole must be differently affected from any
of the rest by the aggregate action of the rest
upon it. The resultant forces exercised by ‘the
aggregate on each unit, being in no case alike
both in amount and direction, cannot produce like
effects on the units. And the various positions
of the parts in relation to any incident force pre-
venting them from receiving it in uniform amounts
and directions, a further difference in the effect .
wrought on them is inevitably produced.” Even
this is not all: Mr. Spencer also points out that “every
differentiated part is not simply a seat of further dif-
ferentiations, but also a parent of further differentia-
tions; since in growing unlike other parts, it becomes
a centre of unlike reactions on incident forces, and by
so adding to the diversity of forces at work adds to the
diversity of effects produced. This multiplication of
effects is proved to be similarly traceable throughout
Nature.” Now, if causes like these are inevitably at
work upon and within the simplest forms of life, no
change in external conditions would be needed in order
to insure alteration or increasing complexity of struc-
ture, through months or years, to say nothing about

ORIGIN OF LIFE. | 37

long ages.* But as a matter of fact (and now we
turn to the second part of Mr. Spencer’s argument),
even if we were to grant that the liability of organ-
isms to increase in complexity of structure, only
“arises from the actions and reactions between organ-
isms and their fluctuating environments,” seeing that
these changes in the environment are, as enumerated
by Mr. Spencer, due to “astronomic, geologic,
meteorologic, and organic agencies,” organisms never
could by any possibility shelter themselves through

* If an increasing complexity of structure does not gradually ensue,
,the specimens of living matter in question will, after a time, undergo
some other molecular rearrangements, resulting in different manifestations
of Heterogenesis—either of an ascending or of a retrograde nature.
_ Heterogenetic transformations from vegetal to animal type are very
| frequent occurrences, whilst heterogenetic degradations (with resolution
into colonies of lower forms) are still more frequent terminations of the
lives of lower animal and vegetal organisms. The latter, especially, are
often mere repetitions of similar, short-lived, and more or less inde-
pendent, units. And if these original forms constantly reappear, so
do the same crystalline forms always show themselves when given
chemical compounds emerge from a state of solution. The different
varieties of living matter (from the point of view of its molecular composi-
tion) are probably innumerable, and each minute difference in molecular
constitution, at whatever period it may have been induced, causes the
living unit either gradually or suddenly to unfold into a different organic
form. Similarly recurring external influences acting upon similarly
constituted units of living matter should constantly engender molecular
variations resembling those which have previously existed, and these
when produced must necessarily lead the living unit through evolutional
changes similar to those which others have undergone. To the ‘‘ wzi-
Sormity of organic laws acting under uniform conditions” (p. 15) we
must, therefore, turn for the true explanation of the persistent recurrence
of myriads of Living as well as of Crystalline Forms.

38 EVOLUTION AND THE

long ages of time from the influence of such external
inciters of change. Mr. Spencer’s explanation of the
cause of the existence of multitudinous almost struc-
tureless organisms at the present day, therefore, as it
appears to me, entirely falls to the ground. The lowest
organisms cannot through long ages escape the inci-
dence of new external conditions (such as we know,
from actual observation, do powerfully modify them),
neither, if they could, should the progress of organiza-
tion thereby entirely cease—since the internal causes
of change would still remain active and still continue
to give rise to a ‘multiplication of effects, as Mr.
Spencer has himself explained.

Thus the existence of such lowest and simplest
organisms as the microscope everywhere reveals at the
present day, is quite irreconcilable with the position
that life-evolution has not occurred since an epoch in-
conceivably remote in Time. As I have elsewhere
asked * :—“Would the Evolutionist really have us
believe that such forms are direct continuations of an
equally structureless matter which has existed for
millions and millions of years without having under-
gone any differentiation ? Would he have us believe
‘that the simplest and most structureless Amceba of
the present day can boast of a line of ancestors stretch-
ing back to such far remote periods that in comparison

* The Beginnings of Life, 1872, vol. i. p. xii.

ORIGIN OF LIFE. 39

with them the primzval men were but as things of
yesterday?” On the other hand, let him admit the
present occurrence of Archebiosis and Heterogenesis,
and both the existence and protean variability of the
lowest organisms are at once readily explained. We
may suppose units of living matter continually seeth-
ing into existence afresh, endowed with enormous
plasticity, and developing either directly or indirectly
‘into the various lower forms of life—thus new
‘recruits are constantly appearing, ever ready to fill up
the gaps occasioned by promotion and death amongst
their predecessors.

I.
THE EVOLUTION HYPOTHESIS,

AND THE ORIGIN OF LIFE.

PART II.

HAVING endeavoured to show how very inconsistent
is the view of certain leading Evolutionists, that
Archebiosis was limited to the earliest stage or stages
of the prodigious period during which living things
have flourished upon the Earth’s surface; and also
how irreconcilable such a notion is with the fact of
the existence of multitudes of almost structureless
organisms at the present day, let us now turn to a
brief consideration of the evidence which is considered
by many to prove the present occurrence of Arche-
biosis. In other words, let us consider the nature of
the evidence which may go to assure the Evolutionist
that he need postulate no arbitrary infringement of
the ‘-uniformity of nature, and that living matter, like |
other kinds of matter, comes into being by virtue
of the same laws or molecular properties as suffice
to regulate its growth.

When Professor Huxley delivered his celebrated
Inaugural Address before the British Association in
1870, by disregarding the consideration of adverse
facts, and bringing to the front a long chain of evi-

ePaper 2

44 EVOLUTION AND THE

dence on a subject which had only a very subordinate
importance for the argument,* he did his best to
convince the public that there was no evidence justi-
fying a belief in the present occurrence of Archebiosis
—and that, on the contrary, the doctrine “omne
vivum ex vivo” was still, not only in the ascendant,
but “victorious along the whole line.” He showed,
by what doubtless appeared to the majority of his
audience a brilliantly conclusive chain of evidence,
that the sole cause of putrefaction in certain expe-
rimental fluids was, as maintained by Pasteur, their
unperceived contamination with atmospheric germs.
Professor Huxley, however, fell into the error which
M. Pasteur had previously committed -— he ascribed
to the presence and influence of germs of Bacteria,
phenomena which have now been shown to be pro-
ducible, and actually produced in many instances,
by the mere dead organic particles which the air
contains in such abundance. Speaking of living
Bacteria germs, Professor Huxley summed up by
saying :—“ Considering their lightness and the wide
diffusion of the organisms which produce them, it is
impossible to conceive that they should not be sus-
pended in the atmosphere in myriads.” Had Pro-
fessor Huxley himself made some careful and dis-
criminating experiments on this part of the subject,

* See Mature, Sep. 22 and 29, 1870.

ORIGIN OF LIFE. 45

he might have found that the supposed impossibility
of conception was entirely delusive. Again, it is
well known that Professor Huxley did at the time
discredit the now admitted fact that Bacteria will
appear in sealed flasks (containing suitable fluids)
whose air has been expelled by boiling.* He dis-
credited this fact because he believed that Bacteria
must have been destroyed by the process of boiling
—and because he was unwilling to believe that they
could be produced de zovoe. He went, as we have
seen, so far as to say that he would rather discredit
scientific evidence concerning the destructive influence
of heat upon living matter, than believe in the present
occurrence of a life-evolution similar to that which
he postulates for the past—although he is quite unable
to assign any valid reason for making such a distinction
between present evolutional potentialities and those
assumed to exist in an unknown past.

What then has been the subsequent progress of |
events? In the first place it has been shown by
Professor Burdon Sanderson, myself, and others, that \
living Bacteria germs are not diffused through the i
air to any appreciable extent,f and this is now a very \
widely accepted doctrine, in spite of its being, as
Professor Huxley imagined, an impossible conception.

* Nature, Sep. 15, 1870, p. 403.
+ Beginnings of Life, 1872, vol. ii. p. 6.

46 EVOLUTION AND THE

Secondly, the fact, which he discredited, of the ap-
pearance of Bacteria in closed flasks after the boiling
of their contents, has been fully substantiated by
' Professor Sanderson, Professor Huizinga, and others.
They have satisfied themselves as to the correctness
of my statements, and have found that swarms of
Bacteria will appear in the course of a few days
within sealed experimental flasks whose fluids have
been previously boiled. Meanwhile it has been shown,
and is believed by the majority of biologists, that the
briefest exposure to the influence of boiling water
(212° F.) is destructive to all living matter. Whilst
_ those who have attempted accurately to define the
precise degree of heat which suffices to kill the
lower infusorial organisms have invariably found
that none of them could survive exposure to a tem-
perature of 140° F. for five minutes.* Indeed all
the simplest forms which can be individually watched
are found to be killed when suddenly exposed to
temperatures below 131° F., and Max Schultze} as
well as Kiihne has ascertained that many of them
perish even at or below 122° F.

Thus it has been established that living protoplasm
is certainly destroyed by sudden exposure to a tem-
perature of 140° F. when in the moist state, irre-

* Proceedings of Royal Society, No. 145 (1873), pp. 325—33I.
+ Das Protoplasma, 1863, p. 63..

ORIGIN OF LIFE. 47

spective of the nature of the fluid in which it may
be immersed; and it has been established that
living matter of the same kind will constantly make
its appearance in many suitable fluids—safely pro-
tected from contamination—within a few days after
the fluids have been exposed to the very much more
destructive temperature of 212° F.—to say nothing of
still higher grades of heat. What conclusion, then,
can be drawn by men of science, but that Archebiosis
still occurs—that living matter, like crystalline matter,
is still capable of arising de novo, or independently
of pre-existing germs? The Evolutionist’s belief in
the uniformity of nature becomes still further justi-
fied by evidence.

Stripped from all unnecessary and unessential
complications, such is our present state of knowledge
on this problem as to the present occurrence or non-
occurrence of Archebiosis. It is easy, of course, for
any person who does not investigate a subject for
himself, and who continues to disregard the investi-
gations of others as long as their results are opposed
to views which he may chance to have adopted, to
continue unshaken by the course of events. But it
is none the less rash and disingenuous for him to
renew (without comment or rectification) the procla-
mation that his particular view is still “victorious
along the whole line,” after the inexorable logic of

48 EVOLUTION AND THE

facts has shown it to be otherwise.* Later in the
day Professor Huxley may, perchance, learn more
readily to distinguish the difference between ‘ mark-
ing time’ and marching.

Again, many of those who do not fully believe in the
Evolution Hypothesis, and who still cling, more or less
fully, to a ‘vitalistic’ philosophy appear bewildered,
if not terrified, by the conclusion which stubborn facts
threaten to force upon them. ‘They behave in the
most inconsistent manner, and,-in dealing with these
facts imperilling their old prepossessions, they find it
convenient to forget for the time and occasion the ordi-
nary rules of scientific research, Although the turning-
_ point of the whole question as to the present occur-

\ rence or non-occurrence of Archebiosis must obviously
depend upon the precise temperature at which living
matter ceases to live, none of those who are opposed
to a belief in its present occurrence, and have taken
part in the controversy, will fairly face this all-import-
ant part of the question. They are alert enough
to realize their danger. For those who have admitted
that Bacteria will appear in previously-boiled fluids
would have no possible loophole for escape, if they
also found the facts I have mentioned concerning the
thermal death-point of Bacteria, and living matter
generally, to be correct. Hence they studiously

* See Professor Huxley’s ‘‘ Critiques and Addresses,” 1873, with his
emarks on this subject at the conclusion of the Preface,

ORIGIN OF LIFE. 49

avoid investigating, or ever writing anything definite,
upon this part of the subject. Taking advantage of
the enormous weight of prejudice and prepossession
against views which they are themselves for one
reason or another unwilling to admit; taking advan-
tage also of collateral complexities with which the
subject is unavoidably beset, they succeed (either
knowingly or unwittingly) in introducing confusion
into their treatment of the question by dealing with
side-issues as though they were essentials. The inco-
herence of their argument seems, in fact, to remain
undiscovered by a large majority of their readers, and
they thus contrive to escape detection—like cuttle-fish
behind the clouds produced by their own ink.

Well may Sir John Herschel have said,* when
speaking of the use and abuse of hypotheses, that
“a bigoted adherence to them, or, indeed, to peculiar
views of any kind, in opposition to facts as they
arise, is the bane of all philosophy.” Well indeed
will it be for Science generally, or the Cause of Truth,
when her followers in all departments learn more
fully to act in accordance with wise precepts such ‘as
these + :—“ Experience once recognized as the foun-
tain of all our knowledge of nature, it follows that
in the study of nature and its laws, we ought at once

* Discourse on the Study of Natural Philosophy, p. 204.

+ Idem, p. 79.
E

50 EVOLUTION AND THE

to make up our minds to dismiss as idle prejudices,
or at least suspend as premature, any pre-conceived
notion of what might or what ought to be the order
of nature in any proposed case, and content ourselves
with observing, as a plain matter of fact, what 7s.
To experience we refer as the only ground of all
physical inquiry. But before experience itself can
be used with advantage, there is one preliminary step
to make, which depends wholly on ourselves: it is
the absolute dismissal and clearing the mind of all
prejudice, from whatever source arising, and the
determination to stand or fall by the result of a
direct appeal to facts in the first instance, and of
strict logical deduction from them afterwards.”

Having said thus much concerning recent events
and the nature of the experimental evidence by which
the occurrence of Archebiosis is to be established, it
will be well now finally to scrutinize the basis of the
old and of the new beliefs in order to ascertain the
relative cogency of the arguments upon which they
rest. We may also test them generally in the way
that hypotheses are usually tested—that is, we may
strive to form an independent judgment upon the
question, as to which of them gives the best expla-
nation of the largest number of phenomena, and which
best enables us to predict new facts.

ORIGIN OF LIFE. 51

Reduced to its simplest form, the fundamental fact
whose interpretation is doubtful may be thus ex-
pressed :—Certain of the most minute living things are
known to appear in some fiuids independently of pre-
existing visible germs.* In explanation of phenomena
of this kind, observed by the aid of the microscope
two hypotheses are offered :—

(1). The hypothesis of Archebiosis (carrying Hetero-
genesis with it as a necessary consequence), which
supposes that these minutest living things have come
into being, and into the region of the visible, by a
process of chemical combination and growth, similar
in kind to that by which crystalline germs originate
in other fluids.

(2). The hypothesis of Panspermism (discrediting .
both Archebiosis and’ Heterogenesis), which supposes
that the minutest living things above referred to
have merely developed in the fluids, owing to the
accidental presence therein of invisible ‘ germs’
thrown off from pre-existing living organisms.

Thus we start with two possibilities which, in the
eyes of the Evolutionist at least, have about an equal
amount of probability. Each hypothesis is also
supported by an analogical argument of considerable
force. :

The analogy tending to support the first hypothesis

* See ‘‘ The Beginnings of Life,” vol. i, pp. 292, ef seg.
E 2

52 EVOLUTION AND THE

is drawn from the essential similarity existing between
living matter and other forms of matter, and from the
fact that Crystals, which originate independently in
fluids, make their appearance in suitable media just
as these lowest living Organisms are observed to do.
Although this analogy has not been dwelt upon by
those who do not share my views on this question,
it is one which many of them would be bound to
accept, since the relationship between crystals and °
organisms is generally admitted by Evolutionists.
This relationship is distinctly affirmed by Mr. Her-
bert Spencer and also just as completely by Professor
Tyndall—as I have already mentioned. Professor
Huxley, moreover, speaks most distinctly on this ~
subject. He says :*—“It is not probable that there
is any real difference in the nature of the molecular
forces which compel the carbonate of lime to assume
and retain the crystalline form, and those which cause
the albuminoid matter to move and grow, select and
form, and maintain its particles in a state of incessant
motion. The property of crystallizing is to crystalliz-.
able matter what the vital property is to albuminoid
matter (protoplasm). The crystalline form corre-
sponds to the organic form, and its internal structure
to tissue structure. Crystalline force being a property
of matter, vital force is but a property of matter.”

* Essay on ‘‘ The Physical Basis of Life,” Fortnightly Review, 1869.

*

ORIGIN OF LIFE. 53

’ The second hypothesis may be said to be based
'/upon (rather than merely supported by) the analogy,

tion’ amongst living things. It is argued that if all

Ij from the observed universality of ‘reproduc-

Br) if

\\

\

|

\

|

a ce

living things, as far as the process is visible, are
‘reproduced’ or derived from pre-existing parent
iving things, so, it is probable that cases in which

the process is invisible would come under the same
i

i

. .| otherwise universal law—expressed by the phrase

omne vivum ex vivo.

But this formula, which has now become a party

mt watchword, bases its supposed universality and

|
| authority, partly (2) upon a simple and incomplete

_ observation of phenomena, and partly (%) upon an

4

‘erroneous assumption.

(a). On the side of observation the formula omne
vivum ex vivo is supposed to derive its authority from
the fact that the experience of mankind generally—
both skilled and unskilled—testifies to its truth.
Here, however, the authority of the formula is in-
validated, on account of a grave misapprehension
as to the real nature of the problem. It is almost
unnecessary to say that observation is of no avail
in regions where it becomes impossible, and conse-
quently that observation cannot tell us whether
previously invisible specks of living matter have
arisen from invisible living germs or by an inde- .

54 EVOLUTION AND THE

ov

pendent elemental mode of origin. Thus, living
matter may have been continually coming into being
all over the surface of. the Earth ever since the time
of man’s first appearance upon it, and yet the
fact that no member of the human race has ever
“seen (or is ever likely to see) such birth, throws
even no shade of doubt upon the probability of
its occurrence.

What then becomes of the supposed validity of this
much respected phrase, omne vivum ex vivo? No
more requires to be said than that it is an instance
of one of those rude and loose inductions, common
amongst the uneducated, and in early days even
amongst scientific men. As the late Mr. Mill*
said :— The unprompted tendency of the mind is
to generalize its experience, provided this points all
in one direction ; providing no other experience of a
conflicting character comes unsought. The notion of
seeking it, of experimenting for it, of dzterrogating
Nature (to use Bacon’s expression) is of much later
growth. The observation of nature by uncultivated
intellects is purely passive; they accept the facts
which present themselves, without taking the trouble
of searching for more.... But though we have
always a propensity to generalize from unvarying
experience, we are not always warranted in doing so,

* System of Logic, 6th edit., vol. i., p. 349.

ORIGIN OF LIFE. 55

Before we can be at liberty to conclude that some-
thing is universally true because we have never known
an instance to the contrary, we must -have reason to
believe that if there were in nature any instances to
the contrary, we should have known of them.” Now
it was only by an utter inattention to this latter all-
important requirement that the “ past experience of
mankind” could ever have appeared to warrant the
induction omue vivum ex vivo.

As Mr. Mill pointed out,* the proposition, “all
swans are white,” must have appeared to Europeans,
not many years ago, an “unequivocal instance of
uniformity in the course of nature.” Subsequent
experience has shown that they were mistaken,
although they and all their predecessors through
many centuries had observed nothing to contradict
this proposition. “The uniform experience therefore
of the inhabitants of the known world, agreeing in
a common result, without one known instance of
deviation from that result, is not always sufficient
to establish a general conclusion.”

(6). The exposure of the untruth of certain old
and crude doctrines concerning ‘spontaneous genera-
tion,’ many of which date from the earliest times ; and
the fact that the belief in this mode of generation has
been successively driven, with increasing knowledge,

* Loc. cit. vol. i., pp. 348, 351-

56 EVOLUTION AND THE

from higher to lower forms of life, till at the last it is
maintained as a mode of origin only for the very
lowest and most minute of living things, has been
regarded by many (as I have already pointed out)
as one of the most weighty arguments against this
kind of generation. But this objection, as before
shown, is robbed of all its seeming strength when it is
said that the modern Evolutionist would only expect
to obtain evidence concerning the de novo origin of
the minutest specks of Living Matter—gradually
emerging into the region of the visible and subse-
quently developing into the most elementary Forms
of Life.

Thus the formula, omne vivum ex vivo, has even
no sufficient @ priori warrant. It is an induction
which has been formed after a partial scrutiny of the
facts—one that has been arrived at, not in accord-
ance with the modern methods of experimental
inquiry, but by the ancient custom of mere passive
observation and enumeration, against which the
founder of the Inductive Philosophy so strongly
raised his voice.*

So far, then, it would seem that at least as much
is to be said in favour of the new as of the old
hypothesis, even from a mere frima facie considera-

* Named by him “ Inductio ‘per enumerationem simplicem, ubi non
reperitur instantia contradictoria.”

ORIGIN OF LIFE. 57

tion of their merits, whilst a closer scrutiny of their
respective foundations tells much more in favour
of the new hypothesis of Archebiosis; in the first
place, because no reason can. be shown why the
process of life-evolution should have been arrested ;
and secondly, because if it does occur at the pre-
sent time, it never could come under the direct
observation of anybody, and consequently the
general experience of mankind concerning the
‘reproduction’ of living things, upon which the
second hypothesis and the dictum omne vivum
ex vivo have been founded, would in no way be.
questioned—the facts would lie altogether outside
this experience.*

But a belief in Archebiosis, whether past or present,
seems to me necessarily to carry with it a belief in
Heterogenesis. So that if Archebiosis be continually
taking place, Heterogenesis should be an equally
common phenomenon. And even for those who
believe that Archebiosis took place in the past though
it has now ceased, Heterogenesis would remain as
a very possible and even probable process from an

* As I have elsewhere said : —“‘ Living matter, like crystalline matter,
is only formable by a synthesis of its elements. As crystals have not
the power of self-multiplication, they have only one mode of origin.
But because organisms have reproductive powers, the obviousness of
these modes of increase has sufficed to cast doubts upon the reality
of the independent origin of living units.”—The Beginnings of Life,

vol. ii., p. 77

58 EVOLUTION AND THE

a priori point of view. Such a process is, in fact,
for living matter what Allotropism is for crystalline
matter. And it so happens that the evidence in
favour of the present occurrence of Heterogenesis
is even stronger and much more varied than that
in favour of the present occurrence of Archebiosis.
Whilst the latter is a strongly warranted inference,
the former is a matter of direct cbservation. So that
concerning the present occurrence of Heterogenesis
we may say, (1), that it follows as an almost neces-
sary consequence from the physical doctrines of life ;
(2), that it is a process which admits of daily obser-
vation by skilled observers; and (3), that it explains
many series of phenomena of the most varied nature,
which would otherwise remain quite inexplicable.*

* It is worthy of note, moreover, that it is the recognition of the
present occurrence of Heterogenesis which is the : il-important neces-
sity. A belief of this kind will carry with it all those important
changes in biological doctrine and in medical science which seem to me
both necessary and inevitable. The further belief as to the present
occurrence of Archebiosis, is an extension of the ‘ Spontaneous Gene-
ration’ doctrine, which, though it may be logically demanded and
warranted, is one of altogether secondary importance ‘n relation to the
changes of doctrine that it would involve. This state of things is the
more important, because a belief in Heterogenesis is open to biologists
of all shades of opinion. Indeed those biologists who still believe in the
existence of a special ‘vital principle,’ would in all probability only
ifner the occurrence of Heterogenesis from such experimental facts as
would warrant, on the part of the Evolutionist, a belief in the present
occurrence of Archebiosis. The Evolutionist, however, is bound to
recognize a difference between living organic matter and dead organic
matter, which the Vitalist, holding himself aloof from positive scientific

ORIGIN OF LIFE. 59

Our present position may perhaps be best illus-
trated by tabulating in parallel columns a statement
of the principal reasons and facts which seem to
support the hypothesis of the present occurrence of
Archebiosis and Heterogenesis, but which are more
or less inexplicable by the hypothesis of Pansper-
mism and an exclusive Life-transmission doctrine.
I am compelled to arrange the matter in this
apparently one-sided form, because I know of no
large classes of facts adverse to the hypothesis
of the present continuance of Archebiosis and

Heterogenesis.

In support of the present occur-
rence of Archebiosis.

1. Our belief in the Continuity
of natural phenomena seems to re-
quire it.

2. The fact that crystalline
matter still comes into being, or
originates under the majority of
those conditions in which its
growth occurs.

3. The fact that the microsco-
pical evidence in favour of origi-
nation is similar in the case of
crystalline and living matter—
both appear to arise de xovo.

Against Panspermism and an ex-
clusive Life-transmission doctrine.

1. The postulation of an in-
fringement of the Continuity of
natural phenomena without ade-
quate cause.

2. The impossibility of explain-
ing why living matter, which still
grows under the most varied con-
ditiuns, should. have ceased to
originate under many of them.

3. This apparent de zovo origin
of specks of living matter is only
to be denied by the assumption
of their derivation from invisible
germs pre-existing in the fluid—
and for this assumption there is no
independent warrant.

evidence so far as these particular doctrines are concerned, might not
feel called uvon to admit.—See ‘The Beginnings of Life,” vol. i,

pp. 244-249.

60 EVOLUTION AND THE

4. Living matter (in the form of
the specks ab sve mentioned) does
appear quickly and abundantly in

Cituations where the uniformity of:

natural phenomena entitles us to
believe that no living matter
(whether visible or invisible) could
have pre-existed.

In’ support of the present occur-
rence of Heterogenesis.*

5. Actual observation with the
microscope of many phenomena of
thiskind. (Vol. II., chaps. xvii.,

xix, —xxii.)

6. The analogy between the
phenomena of Heterogenesis and
those of Allotropism. (Vol. IL,

pp. 49—85.)

7. The fact that the presence of
certain of the lowest organisms
within higher organisms is more
or less determinable at will. (Vol.
IL, pp. 317—345-)

8. Our power of determining
the presence of animal or plant-
like organisms at will, in vessels
containing certain organic infu-
sions. (Vol. II, pp. 209—219,
231—235.)

4. The occurrence of Life-Evo-
lution or Archebiosis in certain
experimental flasks is only to be
denied by making another assump-
tion (as to the power of resisting
heat displayed by living matter),
which is not only without scien-
tific warrant, but is in opposition
to established facts.

Against Panspermism and an
exclusive belief in Homogenesis.

5. The gratuitous assumption
that many otherwise good ob-
servers should all be deceived—
simply because their interpreta-
tions contradict the preconceived
opinions of the majority of natu-
ralists.

6. The absence of all reason why
phenomena of Allotropism should
not show themselves with different
kinds of living matter, as with
simpler molecular compounds.

7. The impossibility of explain-
ing this, except by the disproved
assumption that higher organisms
are always permeated by innume-
rable invisible and generally latent
germs of such lowest organisms.

8. Our power of watching all
the stages by which these animal
or plant-like forms are produced,
from the “pellicle on hay infu-
sions,” and our inability otherwise
to account for their first appear-

* As most of these facts have not been referred to in this commui-
cation, I subjoin, after each pair of paragraphs, references to the
chapters or pages in which the subject has been discussed or referred to
in my work, ‘‘ The Beginnings of Life.”

ORIGIN OF LIFE. 61

9. The Order observable in the
succession of living things which
appear in very many organic infu-
sions :—1I. Bacteria; 2, Monads
and Amceba, or Fungus Germs ;
3. Ciliated Infusoria ; 4. Rotifers.

10. The wide diffusion and con-
stant association of certain organ-
isms (Rotifers, Sloths, and Nema-
toids) which multiply by very large
and well-known germs.

11, Our power of determining
the presence of some of the higher
Fungi (Mushrooms), and of Nema-

oids, at will, in certain organic
mixtures.

12. The wide diffusion and
numerical abundance of Desmids
and Diatoms. (Vol. II, pp. 420,
435—455.)

13. The: incoustancy of par-
ticular species of lower organisms
in the same habitats from year to
year ; and the sudden appearance
of other organisms in enormous
numbers in situations where they
had not previously existed.

14. The uniform association of
certain other organisms with their
accustomed matrices, ag., of par-
ticular kinds of Mould with par-
ticular organic substances, and the
almost invariable association of
Euglenze with Rotifers.

15. The observed relations be-
tween size of matrix and grade of

ance as bodies of comparatively
large dimensions.

g. No reasonable explanation of
this order in accordance with the
hypothesis of Homogenesis, and
with facts known concerning the
distribution of the germs of such
organisms. (Vol. II., pp. 297—
306, 502-535.)

10, These facts, quite irrecon-
cilable with the ascertained absence
of such germs or organisms from
the atmosphere, and an exclusive

doctrine of Homogenesis. (Vol.
IL, pp. 535—538.)
11. These results seemingly

inexplicable from the point of
view of Panspermism and Homo-
genesis, (Vol. IL, pp. 433, 537
note.)

12. Inexplicable by what we
know concerning their absence
from the atmosphere and their
modes of multiplication.

13. Facts either incapable of
being explained by, or directly op-
posed to, the hypothesis of Homo-
genesis and Panspermism. (Vol.

IL, pp. 535s 454)

14. The uniformity of such
associations quite incompatible
with known facts concerning the
prevalence of germs of Fungi,
Euglenz and Rotifers in the air.
(Vol. IL, pp. 302 zote; 535, 508
note.)

15. The impossibility of ex-
plaining away all these observa-

62 EVOLUTION AND THE

organization attained by the allo-
tropic product, where a vegetal
matrix is transformed into an
animal organism.

16. The interchangeability of
those organic forms which are
derivable from originally similar
vegetal matrices.

17. The extreme variability of
the simplest representatives of the
Vegetal Kingdom. (Vol. II,
pp. 150—165, and Appendix D.)

18. The present existence
amongst such lower organisms of
all the gradations by which a
purely sexual process of generation
is gradually evolved. (Vol. IL,
p- 552, and Zuadle.)

19. The explanation of the mys-
terious phenomena of ‘* Alternate
Generation” —and_ especially of
the anomalous exceptions in the
case of Medusee with large eggs.

20. The existence of multitudes
of almost structureless organisms
at the present day. (Vol. IL,
pp. 605—62z2.)

tions, by assuming them to be the
faulty inferences of hasty or un-
skilled observers. (Vol. IL,
chaps. xx.—xxii.)

16. Difficulties similar to those
last-mentioned. (Vol. II., pp.

491—499.)

17. The impossibility of deny-
ing the united but independent
testimony of so many observers,
although such variability seems
irreconcilable with the notion of
these organisms being direct con-
tinuations of an extremely ancient
similar matter which has resisted
change for ages.

18. The impossibility of finding
any explanation of this fact which
shall be consistent with an exclu-
sive doctrine of Life-transmission
and Homogenesis.

19. The absence of all explana-
tion, not only of the phenomena
but of the exceptions thereto.
(Vol. IL, pp. 560—571.)

20. The impossibility of believ-
ing that living matter could per-
sist with so little change for
100,000,000 years or upwards,
whilst other portions of the same
matter have progressively deve-
loped into all the varied forms of
Life that have appeared upon this
globe.

Taken as a whole, the amount of evidence, both
deductive and inductive, seems, to say the least,

ORIGIN OF LIFE. 63

very decidedly to preponderate in favour-of the
present occurrence of Archebiosis and Heterogenesis.
Both fact and reason appear to be notably in-
sufficient on the side of the counter hypothesis. So
that a careful consideration of the respective merits
of the two views—looked at merely as hypotheses
—seems to show in a very unmistakable manner
which is most worthy of our acceptance.

Whilst the hypothesis of Panspermism is based
upon an illegitimate belief, is at variance with many
uniformities of nature, and is wholly incapable of
embracing the required facts, that of Archebiosis and
Heterogenesis is legitimate in its foundation, is not at
all at variance with natural uniformity, and is capable
already of explaining a very wide circle of facts per-
taining to the past and present history of our globe.

But these are the very tests by which we are
accustomed to probe a new hypothesis, with the
view of ascertaining its probable truth or falsity.
What Mr. Justice Grove* said in 1866, when speaking
of the Darwinian hypothesis, is now just as appli-
cable concerning the hypothesis of the present occur-
rence of Archebiosis and Heterogenesis. ~ He said :—
“ The fair question is, Does the newly proposed view
remove more difficulties, require fewer assumptions,

* Presidential Address, in Report of British Association, 1866, p.
xxviii.

64 EVOLUTION AND THE

and present more consistency with observed facts
than that which it seeks to supersede? if so, the
philosopher will adopt it, and the world will follow
the philosopher—after many days.”

But if, even when looked at merely as hypotheses,
that of Archebiosis with Heterogenesis seems so
likely to drive the old doctrine out of the field, we
instinctively look around us for one of those “crucial
instances” which may serve, as has been so often
the case in the history of science, finally to decide
between the contending claims of old and new views.

Now a crucial instance of this kind (or oppor-
tunity of employing the all-decisive experimental
“Method of Difference”), does very fortunately lie
within our reach, and has already been referred to,
Its true value, however, may be now more clearly
seized by the reader; so that for this reason, and
because all past discussions on the question of the
Origin of Life have shown that this is the part of the
subject whose scientific basis is least understood or
most persistently disregarded, I venture, even though
with some slight reiteration to make a few con-
cluding remarks on this crucial test—whose decision
the opponents of Archebiosis attempt to set aside by
a mixture of what appears to me to be, illogical
arguments and groundless assumptions,

ORIGIN OF LIFE, 65

There are only two possible modes of accounting
for the fact that “certain of the most minute living
things are known to appear in some fluids inde-
pendently of pre-existing visible germs.” If there-
fore it can be shown that living though invisible
germs did not pre-exist in certain fluids in which
such minute living things subsequently make their |
appearance as usual, we thereby prove that in such
instances they must have owed their appearance to
the other process—viz., to Archebiosis. Nothing
can be plainer than this; if a given event must be
occasioned by one or other of two causes, and if in
certain instances we can show that the event followed,
notwithstanding the absence of one of these causes,
then the event must have been occasioned by the
other cause. An experiment of this nature is named
a ‘crucial instance’ or experimentum cructs.

‘Let us look then into the nature of the crucial
instance which lies at our disposal in this emergency.

If we wish to ascertain whether living matter
exists, or rather if we wish to make sure that living
matter does not exist in any given fluid, the only
course open to us is to submit the fluid to the in-
fluence of agencies which we have previously ascer-
tained to be capable of ‘killing’ such matter—that
is to say, of putting an end to the combination of

properties the existence of which formerly gave us
F

66 EVOLUTION AND THE

the right to call it ‘living’ matter. As scientific
men, we distinguish one body or class of bodies from
another by the fact of their possessing certain dis-
tinctive attributes or properties—and happily, in this
respect, common usage does not differ from scientific
usage. No one would think of calling any metal
‘gold’ unless it possessed the combination of pro-
perties peculiar to: gold; no physicist would call a
“body a ‘magnet’ unless he could show that it.
possessed magnetic properties; no chemist would
call a fluid ‘alcohol’ unless he could show that such
fluid possessed the known properties of alcohol, and
similarly no biologist would call a body ‘living’
unless it possessed those attributes or properties
which we are accustomed to regard as fundamental
or characteristic. Again, no man of science would
dream of crediting living matter in an imaginary
case with properties different from those which he
has on all previous occasions found it display—if he
had reason to believe that it existed in any given
medium, he would of course look for it on the basis
of its known properties, just as a chemist would
search for gold in any solution thought to contain
it, by having regard only to its accustomed or known
properties. The man of science necessarily starts
from and assumes the truth of the ‘uniformity’ of
natural phenomena at every step—to do otherwise,

ORIGIN OF LIFE. 67

in fact, would’ bea mockery of science. Assumed
invisible germs, therefore, if postulated at all by the
man of science, must be postulated to exist with
properties similar to those of known germs, since
they would all alike be composed of protoplasm, or
simplest living matter. And; again, if he has satis-
fied himself that, in all known: instances where trial
has been made, the sudden exposure of living matter
to a moist heat of 140° F. has proved destructive
to it—that is, has destroyed the combination of
attributes which previously entitled it to be called

‘living ’—he can only conclude that this is a general

truth which he may take for granted in the future.
Being, from the Evolutionist’s point of view, alto-
gether a question of physical or molecular property,
the resistance of protoplasm or living matter to heat
stands upon the same level as that of the degree of

heat necessary to destroy or ‘kill’ one of the simpler ‘
chemical compounds ; or the degree of heat necessary

to cause ebullition in a given fluid. These are all
cases in which, as Mr. Mill said,* “we reckon with
the most unfailing confidence upon uniformity,” so
that “when a chemist announces the existence of
a newly-discovered substance, if we confide in his
accuracy, we feel assured that the conclusions he
has arrived at will hold universally, though the

* System of Logic, 6th edit., vol. i, p. 351.
F 2

68 EVOLUTION AND THE

induction be founded but on a single instance.” Now
here, far from being based upon a single instance, the
fact that very many different kinds of living matter
are killed by a temperature of 140° F., rests upon the
repeatedly recorded observations of several indepen-
dent investigators—upon the observations of Pouchet,
Liebig, Cantoni, Hoppe-Seyler, Kiihne, Max Schultze,
myself, and others.

But as it is the fact that living matter is killed at
140° F., and as it is also true that certain fluids heated
to much higher temperatures (to 212° F. and upwards)
and subsequently exposed to certain conditions free
from all possibility of contamination with living
matter, will shortly swarm with the living things
whose mode of origin we desire to learn, the man
of science is compelled to conclude that such living
Organisms must have originated independently of
living germs, and, therefore, after the manner of
Crystals. Here then is our ‘crucial instance.’

Thus by this simple resort to the ‘Method of
Difference,’ we are enabled to solve our problem, and
finally decide between two rival hypotheses. The
occurrence of Archebiosis is, therefore, established as
a natural phenomenon, and like other natural pheno-
mena, we are entitled to believe not only that it will
recur whenever the conditions are similar or otherwise
suitable, but that it has been in operation through

ORIGIN OF LIFE. 69

the whole of that long vista of bygone ages during
which the surface of our Earth has been occupied by
living things.

Having been compelled by experimental evidence
and observation to believe in the present occurrence
of Archebiosis and Heterogenesis, I will now strive
to lay before the reader some of the principal and
most interesting consequences resulting from such
a recognition of natural uniformity. This I will
endeavour to do in as short a space as is com-
patible with my object of giving the intelligent reader
some notion of the general scope and nature of the
biological doctrines which recent experiments and
observations seem to force upon us. A detailed
statement of the facts and reasons upon which the
following views are based, may be found by those
who desire it elsewhere.*

Living matter is constantly being formed de novo
in obedience to.the same laws and tendencies as
those which determine all the more simple chemical
combinations. The qualities which we summarize
under the word ‘life’ are in all cases due to the
combined molecular actions and properties of the
aggregate that displays them, just as the properties

* The Beginnings of Life,

70 EVOLUTION AND THE

which we include under the word ‘magnetism’ are
due to particular modes of collocation that have
been assumed by the molecules of iron.

Living matter is especially characterized by the
complexity of its molecules and their state of con-
tinual intestine movement. This peculiarity, as well
as other related qualities, make the simplest aggre-
gates of such matter especially prone to undergo
those secondary structural re-arrangements which all
plastic and homogeneous masses of matter are liable
to exhibit. And although in the case of living
matter these re-arrangements manifest themselves
by producing what we call ‘organization,’ still the
forms and structures which many of the lowest
organisms tend to assume are entirely referrible to
the polarity of their molecules—just as the forms
of crystals are the results of like, though simpler,
polarities.

And, speaking generally, the complexity of organ-
ization attainable by the lower animal forms gradually
tends to increase as the masses of matter from
which new forms are to develop increase in size:
owing apparently to the multiplication of effects that
may be induced by the production of several series
of molecular re-arrangements within the larger aggre-
gates, The changes progress, however, in each case
till a condition of moving equilibrium is established

ORIGIN OF LIFE. 71

between the sum total of molecular actions taking
place within the living aggregate and the forces of
its environment.

The power of undergoing spontaneous division
(fission or gemmation), which is manifested by living
matter, and upon which all the phenomena of ‘re-
production’ depend, is apparently one of its most
fundamental properties, though it is in itself a result
of that molecular mobility and complexity to which
we have previously referred.

And it is this same molecular mobility which
makes an aggregate of living matter, in the form of
a simple organism, very prone to undergo changes
in its intimate constitution—either ‘spontaneously,’
or under the incidence of a known change in external
forces. Some new conditions may not visibly affect
it, others may cause its ‘death,’ whilst others again
may affect it only to such an extent as to bring
about some modification of its molecular constitution,
which, by reason of an altered polarity, entails a
more or less marked transformation of form and
structure (Heterogenesis).

Thus the marvellous convertibility of lower organ-
isms, their ability to undergo self-multiplication,
and their tendency to become (under favourable con-
ditions) more complexly organized, are all necessary
consequences of those physical doctrines concerning

72 EVOLUTION AND THE

‘life,’ the truth of which is deemed to have been
established by previously-recorded experiments.

-These myriads of lowest forms of life, multiplying
only by processes of fission and gemmation, con-
stitute an inextricably-tangled plexus of more or less
convertible animal or vegetal forms (corresponding
pretty closely with the Protista of Professor Haeckel)
which, though often reappearing, are for the most
part evanescent and transitory states, either of com-
paratively new-born living matter, or of portions of
matter which have become individualized by hetero-
genetic processes occurring in the substance of the
higher forms of life. But, howsoever derived, such
forms constitute a vast assemblage of ‘Ephemero-
morphs’ amongst which Heterogenesis occurs almost
as frequently as Homogenesis.*

Gradually, however, the first traces of those pro-
cesses of ‘conjugation’ and of internal gemmation
begin to manifest themselves, which subsequently be-
come perfected into ‘sexual’ modes of reproduction.

And when animal and vegetal organisms mani-
festing that cyclical homogenesis known as ‘alternate
generation,’ appear upon the scene, and with them
those simpler allies (formed from large germs), which

* The song of the Ephemeromorphs might be, in the words of Ovid,
“Corpora vertuntur ; nec quod fuimusve, sumusve,
Cras erimus.”

ORIGIN: OF LIFE. 73

‘undergo a direct process of development, we first
begin to obtain such regularly-recurring and definite
assemblages of animal and vegetal forms as are
usually grouped under the name of ‘species.’

Until such assemblages of repeating individuals
make their appearance—that is, until Homogenesis
becomes the rule—the ‘laws of Heredity’ can
scarcely be said to come into operation. Hence, the
complexly-interrelated individuals constituting this
vast underlying plexus of Infusorial and Cryptogamic
life must remain wholly uninfluenced, so far as their
form and structure are concerned, by what Mr. Darwin
has termed ‘Natural Selection.’ Such vegetal and
animal organisms, however, gradually tend to become
more and more complex. An ascending develop-
ment takes place; and as this occurs, the causes
which originally sufficed to determine their form and
structure, and which for a time continue to induce
comparatively rapid and marked deviations, become
less and less capable of bringing about structural
modifications during the life of the individual.
Changes which are now less rapidly accomplished
have to be perfected in a succession of individuals.
Thus is the operation initiated of those subtle and
more slowly modifying agencies which have been
so admirably illustrated by Mr. Darwin.

But amongst. specific forms of slight complexity

74 EVOLUTION AND THE

the influence of Natural Selection as a modifying
agent is probably much less important than it is
amongst more active and complex animal forms: and
in all cases its action in producing change may be
assisted by ‘spontaneous’ internal changes in the
molecular activity of certain parts of the organism,
or by other internal changes more obviously induced
by modifications in the sum total of ‘external con-
ditions’ acting upon the organism.

Each cause of specific modification, however,
whether acting alone or in concert with one of the
other producers of internal change, can only come
into play in subordination to the ever potent laws
of ‘organic polarity,’ by which a multiplication of
effects is apt to be induced.

In addition to these conclusions concerning the
present order of events, we seem warranted in draw-
ing the following speculative deductions concerning
the past:—

An elemental origin of living matter similar to
that which takes place at the present day, and, in
addition, all the related heterogenetic phenomena,
have probably been taking place on the surface of
our globe since the far remote period when such
matter was first engendered.

The countless myriads of living units which have
been evolved in different ages of the world’s history

ORIGIN OF LIFE, 75

must, in each period, have given rise to innumerable
multitudes of what have been called ‘trees of life,’
branching out into animal and vegetal forms of
almost inconceivable variety. Myriads of these
‘trees,’ including all their branches and innumerable
ramifications, may have wholly died out during the
many vicissitudes of the earth’s surface and the long
lapse of ever fruitful ages; though the descendants
or ultimate ramifications of some of such trees —
dating back to quite different and perhaps far-distant
epochs—may still survive. How far, however, the
roots of any of the ‘trees’ from which the existing
higher forms of life are derived, may have extended
back into the depths of geologic time, we are utterly
unable to estimate.

Throughout all this life-evolving period of the
history of our globe, the progress of ‘ organization’
seems to have been essentially similar. And that
this should be so, seems readily explicable by the
consideration that living things, both as regards their
origin and their subsequent differentiation or develop-
ment, are the immediate products of ever-acting
natural laws or material properties. These properties
should act therefore now as they have ever done, and
so continue to produce almost similar effects.

The lower the forms of life—that is, the nearer
they are to their source—the greater seems to have

76 EVOLUTION, ORIGIN OF LIFE.

been the similarity amongst those which have been
produced in different ages—just as the lowest forms
are now similar in all regions of the earth. On the
other hand, the longer any particular ‘tree of life’
has lived (of which there have been countless multi-
tudes born in each. age), the wider may be the diver-
gence of form presented by the ultimate outgrowths
of any two of them, or of outgrowths of similar rank
produced from trees which have developed during
different ages—especially when the assemblages of
organisms constituting one of these ideal trees, have
lived under the influence of any unusual set of telluric
conditions. :

The ‘vertebrate’ grade of organization may have
been many times attained by ultimate branches of
_ different ‘trees of life’ But how long or when the
particular ‘tree of life, from one of the branches of
: which Man was developed, appeared upon the earth,
it is quite impossible to-say.

II.

ON THE TEMPERATURE AT WHICH BACTERIA,
VIBRIONES, AND THEIR SUPPOSED GERMS
ARE KILLED WHEN IMMERSED IN FLUIDS
OR EXPOSED TO HEAT IN A MOIST STATE.

FoR more reasons than one we may, perhaps, now
look back with advantage upon the friendly contro-
versy carried on rather more than a century ago
between the learned and generous Abbé Spallanzani
and our no less distinguished countryman Turberville
Needham. Writing concerning his own relation to
Needham, the Abbé said*, “I wish to deserve his
esteem whilst combating his opinion” ; and in accord- |
ance with this sentiment, we find him treating his
adversary’s views with great respect, and at the same
time repudiating much of the empty and idle criticism
in which so many of Needham’s contemporaries in-
dulged with regard to his work. This criticism,
Spallanzani sayst, “Without looking into details,
contented itself by throwing doubt upon some of the
facts, and by explaining after its own fashion others
whose possibility it was willing to admit.” He more-
over warmly reprobated the ignorant and disrespectful

* Nouvelles Recherches sur les Découvertes Microscopiques et la
Génération des Corps Organisés, &c. London and Paris, 1769, vol. i.,
p. 69. + Loc. cit., p. 9.

So THE DEATH-POINT OF

statements made by an anonymous writer who had
shown himself little worthy of being heard upon the
subjects in dispute. Spallanzani on this occasion
very wisely said* :—“ When it is a question concerning
observations and experiments, it is necessary to have
repeated them with much circumspection before
venturing to pronounce that they are doubtful or
untrustworthy. He who will allow himself to speak
of them with contempt, and who can only attempt to
refute them with writings composed by the glimmer
derived from a treacherous lamp, will not find him-
self in a condition to retain the esteem of learned
men.” The anonymous writer (in his ‘Lettres a un
Américain’), to whom Spallanzani referred, had gone
so far as to doubt the statements of Needham as to
the constant appearance of organisms in infusions
which had been previously boiled, and also intimated
that even if they were to be found, it was only
because they had been enabled to resist the de-
structive influence of the boiling fluid. This latter
assertion was emphatically denied by Spallanzani,
his denial being based upon a most extensive series
of experiments with eggs in great variety and
with Seeds of all degrees of hardness; these were
all found to be killed by a very short contact with
boiling water. Spallanzani had thoroughly satisfied
» Loc. cit, p. 114.

BACTERIA AND THEIR GERMS. 81

himself that even very thick-coated seeds could
not resist this destructive agent ; whilst he thought
that the idea, entertained by some, of the eggs of
the lowest infusoria being protected from the in-
jurious influence of the boiling water by reason of
their extreme minuteness, was a supposition so
improbable as scarcely to deserve serious con-
sideration. Such a notion was, he thought, wholly
opposed to what was known concerning the trans-
mission of heat. Whilst, therefore, the opinion of
those who believe that eggs have the power of
resisting the destructive influence of boiling water
could be fully refuted, Spallanzani thought it by
no means followed that the infusoria which always,
after a very short time, appeared in boiling in-
fusions had arisen independently of the existence
of eggs. The infusions being freely exposed to the
air, it was very possible that this air had intro-
duced eggs into the fluids, which by their develop-
ment had given birth to the infusoria.*

After the lapse of a century it has at last been
clearly shown that this supposition of aérial con-

» A few pages further on this view is thus shortly expressed :—“ Il
est évident que touts les tentatives faites avec le feu, peuvent bien servir
a prouver que les animaux microscopiques ne naissent point des ceufs que
l'on supposait exister dans les infusions avant qu’on leur fit sentir le feu;
mais cela n’empéche pas qu’ils n’aient pu étre formés de ceux qui auront
été portés dans les vases aprés Vébullition.”

G

82 THE DEATH-POINT OF

tamination ‘advanced by Spallanzani (warrantable
and natural as it was at the time) is one which, in
the great majority of cases, is devoid of all founda-
tion in fact, so far as concerns the organisms
essentially associated with processes of putrefaction,
viz. Bacteria and Vibriones. The means of proving
this statement based upon independent observations
made by Professor Burdon Sanderson and myself,
were recently submitted to the consideration of
the Royal Society:t Before the reading of this
communication I was under the impression that
almost everyone of those who had taken part in
the controversies which had been carried on both
here and abroad concerning the Origin of Life
were prepared to admit, as Spallanzani had done,
that the eggs or germs of such organisms as appear
in infusions were unable to survive when the infusions
containing them were. raised to the temperature at
which water boils. This impression was produced
in part by the explicit statements on this subject
that had been made by very many biologists, and
also in part by a comparatively recent and authori-
tative confirmation which this view as to the
destructive effects of boiling infusions upon Bac-
teria had received. Little more than two years
ago Professor Huxley, as President of the British
* See Proceedings of Royal Society, No. 141, 1873, p. 129.

BACTERIA AND THEIR GERMS. 83

Association for the Advancement of Science
recorded experiments in his Inaugural Address
which were obviously based upon this belief as
a starting-point; and subsequently, in one of the
Sectional Meetings, after referring to some of my
experiments, and to the fact that all unmistakeably
vital movements ceased after Bacteria had been
boiled, Professor Huxley added* :—“I cannot be
certain about other persons, but I am of opinion
that observers who have supposed that they have
found Bacteria surviving after boiling have made 7
the mistake which I should have done at one time, |
and, in fact, have confused the Brownian movements .
with zrue living movements.” Some eminent
biologists do not now (in reference to the experi-
ments cited in my last communication) suggest
that the organisms found in the infusions were
dead and had been there before the fluids were
boiled: they express doubts concerning that which
seems formerly to have been regarded as estab-
lished, and now wish for evidence to show that
the germs of Bacteria and Vibriones are killed in a
boiling infusion of hay or turnip, as they have been
proved to be in ‘ Pasteur’s Solution’ and in solutions
containing ammonic tartrate and sodic phosphate.
With the view of removing this last source of
» See Report in Quart. Journ. of Microscop. Science, Oct. 1870.
G2

84 THE DEATH-POINT OF

doubt more effectually, and also of refuting the
unwarrantable conclusion* of M. Pasteur, to the
effect that the germs of Bacteria and Vibriones
are not killed in neutral or slightly alkaline fluids
at a temperature of 212°F., I almost immediately
after the reading of my last communication com-
menced a fresh series of experiments.

Nearly two years ago, in my ‘Modes of Origin
of Lowest Organisms, I brought forward evidence
to show that Bacteria, Vibriones, and their sup-
posed germs are killed at a temperature of 140° F.
(60°C.) in neutral or very faintly acid solutions
containing ammonic tartrate and sodic phosphate,
and also evidence tending to show that these living
units were killed in neutral infusions of hay and
in acid infusions of turnip at the same temperature.

The crucial evidence adduced concerning the
degree of heat destructive to Bacteria, Vibriones,
and their germs, in the saline solution, was of this
nature. The solution had been shown to be incapable
of engendering Bacteria and Vibriones (under all
ordinary conditions) after it had been boiled, although
it still continued capable of supporting the life and

* Reasons for this opinion have been fully set forth in ‘‘The Begin-
nings of Life,” vol. i., pp. 374 é seg. ; or the discriminating reader may
at once find my justification for this expression by reading pp. 58—66,
of M. Pasteur’s memoir in ‘‘ Anr.. de Chim. et de Physique,” 1862,

BACTERIA AND THEIR GERMS. 85

encouraging the rapid multiplication of any of these
organisms which were purposely added to it. Some
of this boiled solution therefore was introduced into
flasks previously washed with boiling water; and
when the fluids had sufficiently cooled, that of each
flask was inoculated with living Bacteria and
Vibriones—in the proportion of one drop of a fluid
quite turbid with these organisms to one fluid ounce
of the clear saline solution.* These mixtures con-
taining an abundance of living organisms were then
heated to various temperatures, ranging from 122° F.
(50°C.) to 167°F. (75°C.); and it was invariably
found that those which had been heated to 122° or
131°F, became quite turbid in about two days, whilst
those which had been raised to 140° F., or upwards, as
invariably remained clear and unaltered. The turbidity
in the first series having been ascertained to be due to
the enormous multiplication of Bacteria and Vibriones,
and it being a well-established fact that such organ-
isms when undoubtedly living always rapidly multiply
in these fluids, the conclusion seemed almost inevit-
able that the organisms and their germs must have
been killed in the flasks which were briefly subjected
to the temperature of 140°F. How else are we to

* Fuller details concerning these experiments may be found in the
little work already mentioned at pp. 51—56, and also in ‘‘ The Begin-
nings of Life,” vol. i., pp. 325—332.

86 THE DEATH-POINT OF

account for the fact that these fluids remained quite
unaltered although living organisms were added to
them in the same proportion as they had been to those
less-heated fluids which had so rapidly become turbid?
Even if there does remain the mere possibility that the
organisms and their supposed germs had not actually
been killed, they were certainly so far damaged as to
be unable to manifest any vital characteristics. The
heat had, at all events, deprived them of their powers
of growth and multiplication ; and these gone, so little
of what we are accustomed to call ‘life’ could remain,
that practically they might well be considered dead.
And, as I shall subsequently show, the production of
this potential death by the temperature of 140°F,
enables us to draw just the same conclusions from
other experiments, as if such a temperature had pro-
duced a demonstrably actual death.* Seeing also that
these saline solutions were inoculated with a fluid in
which Bacteria and Vibriones were multiplying rapidly,
we had aright to infer that they were multiplying in
their accustomed manner, “as much by the known
method of fission, as by any unknown and assumed
method of reproduction.” So that, as I at the time
said,f “These experiments seem to show, therefore,
that even if Bacteria do multiply by means of invis-

* See p. 95.
+ Modes of Origin of Lowest Organisms, 1871, p. 60.

BACTERIA AND THEIR GERMS. 87

ible gemmules, as well as by the known process of
fission, such invisible particles possess no higher power
of resisting the destructive influence of heat than the
parent Bacteria themselves possess.”

This is, in fact, by far the most satisfactory kind of
evidence that can be produced concerning the powers
of resisting heat enjoyed by Bacteria and Vibriones,
because it also fully meets the hypothesis as to their
possible multiplication by invisible gemmules possessed
ofa greater power of resisting heat,and because no mere
inspection by the microscope of dead Bacteria can en-
title us positively to affirm that they are dead, even
though all characteristically vital or ‘true. living’
movements may be absent.

Facts of a very similar nature were mentioned in
the same work strongly tending to show that Bacteria
and Vibriones are also killed at the same temperature
in other fluids, such as infusions of hay or turnip.
These facts were referred to in the following state-
ment* :—“ Thus, if on the same slip, though under
different covering-glasses, specimens of a hay-infusion
turbid with Bacteria are mounted, (2) without being
heated, (2) after the fluid has been raised to 122° F. for
ten minutes, and (c) after the fluid has been heated to
140° F. for ten minutes, it will be found that in the
course of a few days the Bacteria under a and 6 have
notably increased in quantity, whilst those under ¢ do
* Modes of Origin of Lowest Organisms, 1871, p. 60.

8 THE DEATH-POINT OF

not become more numerous, however long the slide is
kept. Facts of the same kind are observable if a
turnip-infusion containing living Bacterza is experi-
mented with; and the phenomena are in no way differ-
ent if a solution of ammonic tartrate and sodic
phosphate (containing Bacteria) be employed instead
of one of these vegetable infusions. The multiplica-
tion of the Bacteria beneath the covering-glass, when
it occurs, is soon rendered obvious, even to the naked
eye, by the increasing cloudiness of the film.”

The facts just cited concerning the behaviour of thin
films of turbid infusions which had been heated to
different temperatures gave me the clue as to the
proper direction of future work. It would seem that
when mounted in the manner described, such thin
films of infusion continue capable of supporting and
favouring the multiplication of any already existing
Bacteria and Vibriones, although under such con-
ditions no new birth of living particles appears to take
place even in these fluids. The question then arose as
to whether, by subjecting larger quantities of the same
infusions to any particular sets of conditions, we could
ensure that they also should continue to manifest the
same properties ; because if so, it would be almost as
easy to determine the death-point of Bacteria and
Vibriones when exposed to heat in these infusions, as
it had been to determine it for the saline solutions
already mentioned.

BACTERIA AND THEIR GERMS. 89

It was pointed out by Gruithuisen early in the
present century, that many infusions, otherwise very
productive, ceased to be so when they were poured
into a glass vessel whilst boiling, and when this was
filled so that the tightly-fitting stopper touched the
fluid. Having myself proved the truth of this asser-
tion for hay-infusion, it seemed likely that, by having
recourse to a method of this kind, I should be able to
lower the virtues of boiled hay- and turnip-infusions,
to the level of those possessed by the boiled saline
solution with which I had previously experimented—
that is, to reduce them to.a state in which, whilst they
appear (under these conditions) quite unable of them-
selves to engender Bacteria, Vibriones, they continue
well capable of favouring the rapid multiplication of
such organisms.

This was found to be the case; and I have
accordingly performed upwards of one hundred ex-
periments with inoculated portions of these two
infusions raised to different temperatures. The
mode in which the experiments were conducted was
as follows :—

Infusions of hay and turnip of slightly different
strengths were employed. These infusions, having
been first loosely strained through muslin, were
boiled for about ten or fifteen minutes, and then
whilst boiling strained through ordinary Swedish
filtering-paper into a glass beaker which had pre-

go THE DEATH-POINT OF

viously been well rinsed with. boiling water. A
number of glass bottles or tubes were also prepared,
which, together with their stoppers or corks, had
been boiled in ordinary tap water for a few minutes.*
They were taken. out full of the boiling fluid; and
the stoppers or corks being at once inserted, the
vessels and their contents were set aside to cool.
When the filtered infusion of hay or turnip had
been rapidly cooled down. to. about 110° F. (by
letting the beaker containing it stand in a large
basin of cold water), it was inoculated with some
of a turbid infusion of hay swarming with active
Bacteria and Vibriones—in the proportion of one
drop of the turbid fluid to each fluid ounce of the
now clear filtered infusion.t The beaker was then
placed upon a sand-bath, and its contained fluid
(in which a thermometor was immersed) gradually
raised to the required temperature. The fluid
was maintained at the same temperature for five
minutes by alternately raising the beaker from and
replacing it upon the sand-bath. The bottles to
be used were then one by one uncorked, emptied,

* The vessels employed have varied in capacity from two drachms to
four ounces ; some have been provided with glass stoppers and others
with very tightly fitting corks; and the latter I find have answered quite
as well as the former. On the whole I have found tightly corked one-
ounce phials to be about the most convenient vessels to employ in these
inoculation experiments.

+ It was found desirable to filter the infusions after they had been
boiled, because the boiling generally somewhat.impaired their clearness.

BACTERIA AND THEIR GERMS. 91

and refilled to the brim with the heated inoculated
fluid.* The corks or stoppers were at once very
tightly pressed down so as to leave no air between
them and the surface of the fluids. The beaker
was then replaced upon the sand-bath and the gas
turned on more fully, in order that the experi-
mental fluid might be rapidly raised to a temperature
9 F.(5°C.) higher than it had been before. After
five minutes’ exposure to this temperature other
bottles were filled in the same manner, and so on
for the various temperatures the influence of which
it was ‘desired to test..

Thus prepared, the bottles and tubes have been
exposed during the day to a temperature ranging
from 65°F to 75°F. And generally one had not to
wait long in order to ascertain what the results were
to be. In some cases, if the contents of the vessels
were to become turbid, this was more or less mani-
fest after an interval of forty-eight hours; in other
cases, however, the turbidity manifested itself three
or more days later: the reason of this difference will
be fully discussed in a subsequent communication.

; For the sake of simplicity and. brevity, the ne-
cessary particulars concerning the 102 experiments
have been embodied in the following Table :—

* At this stage, of course, very great care is needed in order to avoid
all chance of accidental contamination either with living organisms or
with unheated fragments or particles of organic matter. .

92

THE DEATH-POINT OF

Inoculation Experiments made with the view of ascertaining the Tem-
peratures at which Bacteria, Vibriones, and their supposed Germs
are killed in Organic Infusions.

NEUTRAL HAY-INFUSION.

1. Number Results
Temp. to “of Date | at Expiration
which . of Turbidity,

Experiments if of the
exposed made. Hany. 8th day.
ol E ) 1 24 hours. Turbid.
131° F. 7 48 hours. All turbid.

if 1 in 48 hours,
140° F, 9 Aa ed All turbid.
( rin 8 days, .
op 2in 5 days. } re turbid.
nao 4 { rin 8 days One clear.
158° F. 15 aes All clear.
167° F. 4 ae All clear.
176° F.
(80° C.) 12 sve All clear.
ACID TURNIP-INFUSION.
Number Results
a D: beaaeas
rent ‘ E. ee of Turbidity, at een
exposed. aaa dé: if any. 8th day.
122° F, ase ? “ eo
130° F. 7 Ge dina All turbid.
6 in 4o hours,
140° F, 12 4in 3 days. } All turbid.
2in 4 days. f
rin 3 ea % aa
3in 5 days. even turbid.
149° F. a2 rin 7 days. {re clear.
2in 8 days,
158° F, 17 see All clear.
167° F. 4 oe All clear.
176° F. a eee sa

BACTERIA AND THEIR GERMS. 93

The experimental results above tabulated seem
naturally divisible into three groups. Thus, when
heated only to 131° F., all the infusions became
turbid within two days, just as the inoculated saline
solutions had done.* Heated to 158°F. all the in-
oculated organic infusions remained clear, as had
been the case with the saline solutions in my previous
experiments when heated to 140° F. There remains,
therefore, an intermediate heat zone (ranging from a
little below 140° to a little below 158° F.) after an
exposure to which the inoculated organic infusions
are apt to become more slowly turbid, although in-
oculated saline solutions raised to the same tempera-
tures invariably remain unaltered. The full explana-
tion of these apparent anomalies I propose to make
the subject of a future communication to the Royal
Society; meanwhile we may quite safely conclude
that Bacteria, Vibriones, and their supposed germs are
either actually killed or else completely deprived of
their powers of multiplication after a brief exposure
to the temperature of 158° F, (70° C).

This evidence now in our possession as to the limits
of ‘vital resistance’ to heat displayed by Bacteria,
Vibriones, and their supposed germs in neutral saline
solutions, and in neutral or acid organic infusions, is

* In the experiments already referred to, p. 85.

94 THE DEATH-POINT OF

most pertinent and valuable when considered in rela-
tion to that supplied by other sets of experiments
bearing upon the all-important problem of the Origin
of Life. These latter experiments alone may possibly
leave doubt in many minds; but the more thoroughly
they are considered in relation to the evidence
brought forward in this communication, the more
fully, I venture to think, will every lingering doubt as
to the proper conclusion to be arrived at be dispelled.

Thus we now know that boiled turnip or hay-infu-
sions exposed to ordinary air, exposed to filtered air,
to calcined air, or shut off altogether from contact
with air, are more or less prone to swarm with Bacteria
and Vibriones in the course of from two to six days;
but, placed under slightly different conditions such as
were employed in the inoculation experiments above
quoted, although infusions of the same nature do
not undergo ‘spontaneous’ putrefactive changes, yet
when living Bacteria and Vibriones are added, and
not subsequently heated, putrefaction zzvariably takes
place and the fluids thus situated rapidly become
turbid, There is therefore nothing in the conditions
themselves tending to hinder the process of putrefac-
tion, so long as living units are there to initiate it,
Our experiments now show that as long as the added
Bacteria, Vibriones, and their supposed germs are
subjected to a heat not exceeding 131°F. (55°C.),

BACTERIA AND THEIR GERMS. 95

putrefaction invariably occurs within'two days; whilst,
on the contrary, whenever they are subjected to a
temperature of 158° F. (7o°C.) putrefaction does not
occur. To what can this difference be due, except to
the fact that the previously living organisms, which,
when living, always excite putrefaction, have been
killed by the temperature of 158°F.? It would be of
no avail to suppose that the absence -of putrefaction
in these latter cases is due to the fact that a heat of
158° F., instead of killing the organisms and their
germs, merely annuls their powers of reproduction,
because in the other series of experiments (with which
these have to be compared), where similar fluids are
exposed to ordinary or purified air, or are shut off
from the influence of air altogether, the most active
putrefaction and multiplication of organisms takes
place in two, three, or four days, in spite of the much
more potent heat of 212° F. to which any pre-existing
germs or organisms must have been subjected. The
supposition, therefore, that the Bacterza, Vibriones, and
their germs were not killed in our inoculation experi-
ments at the temperature of 158° F., but were merely
deprived of their powers of reproduction, would be no
gain to those who desire to stave off the admission
that Bacteria and Vibriones can be proved to arise de
novo in certain cases, Let us assume this (which is
indisputably proved by these inoculation experi-

96 THE DEATH-POINT OF

ments), viz. that an exposure to a temperature of 158°
(70° C.) for five minutes deprives Bacteria, Vibriones,
and their germs of their usual powers of growth and
reproduction—that is, that it reduces them to a state
of potential, if not necessarily to one of actual death.
What end would be served by such a reservation ?
The impending conclusion could not be staved off by
means of it. The explanation of what occurs in the
other set of experiments, where the much more potent
heat of 212° F. is employed, still would not be possible
without having recourse to the supposition of a de
novo origination of living units, so long as those which
may have preexisted in the flasks could be proved to
have been reduced to such a state of potential death.
It would be preposterous, and contrary to the whole
order of Nature, to assume that the vastly increased
destructive influence of a heat of 212° F. had restored
vital properties which a lesser amount (158° F.) of the
same influence had completely annulled.

The evidence supplied by these different series of
experiments, in whichever way it is regarded, as it
seems to me, absolutely compels the logical reasoner
to conclude that the swarms of living organisms
which so often make their appearance in boiled infu-
sions treated in one or other of the various modes
already proved to be either destructive or exclusive
of preexisting living things are the products of a

BACTERIA AND THEIR GERMS. 97 |

new brood of ‘living’ particles, which, in the absence
of any coexisting living organisms, must have taken
origin in the fluid itself. For this mode of origin of
living units, so long spoken of and repudiated as
‘spontaneous generation, I have proposed the new
term Archebiosis.

Til.

FURTHER OBSERVATIONS ON THE TEM-
PERATURE AT WHICH #SACTERIA
VIBRIONES, AND THEIR SUPPOSED
GERMS ARE KILLED WHEN EXPOSED TO
HEAT IN A MOIST STATE; AND ON THE
CAUSES OF PUTREFACTION AND FER-
MENTATION.

WHILST a heat of 140° F. (60° C.) appears to be
destructive to Bacteria, Vibriones, and __ their
supposed germs ina neutral saline solution, a heat
of 149° or of 158°F. is often necessary to prevent
the occurrence of putrefaction in the inoculated
fluids when specimens of organic infusicns are
employed. What is the reason of this difference ?
Is it owing to the fact that living organisms are
enabled to withstand the destructive influence of
heat better in such fluids than when immersed in
neutral saline solutions? At first sight it might
seem that this was the conclusion to be drawn
We must not, however, rest satisfied with mere
superficial considerations.

The problem is an interesting one; yet it should
be clearly understood that its solution, whatever it
may be, cannot in the least affect the validity of
the conclusion arrived at in my last paper, viz.

' ‘that living matter is certainly capable of arising
de novo. We were enabled to arrive at the con-

102 THE DEATH-POINT OF BACTERIA

clusion above mentioned regarding Archebiosis by
starting with the undoubted fact that a heat of
158°F. reduces to a state of potential death all
the Bacteria, Vibriones, and their supposed germs
which an organic infusion may contain. The
inquiry upon which I now propose to enter, there-
fore, touching the degree of heat below this point
which may suffice to kill such organisms and their
supposed germs in an organic infusion, and touch-
ing the cause of the delayed putrefaction apt to
take place in inoculated organic infusions which
have been heated to temperatures above 140° and
below 158°F., is one lying altogether outside the
chain of fact and inference by which the occurrence
of Archebiosis is proved.

It seems to me that the solution of the problems
which form the subject of the present communica-
tion can only be safely attempted by keeping
constantly before our minds two main considera-
tions :—

Thus, in the experiments whose results it is
now our object to endeavour to explain, the fluids
have been inoculated with a compound consisting
partly (a) of living units, and partly (4) of a drop
of a solution of organic matter in a state of
molecular change; so that in many cases where
putrefaction has been initiated after the inoculating

AND THE CAUSES OF FERMENTATION. 103

compound has been heated to certain temperatures,
there is the possibility that this process of putrefac-
tion may have been induced (in spite of the death
of the organisms and their germs) owing to the
influence of 4, the dissolved organic matter of the
inoculating compound; that is to say, the heat to
which the mixture has been exposed may have
been adequate to kill all the living units entering
into the inoculating compound, although it may
not have been sufficient to prevent its not-living
organic matter acting as a ferment upon the
infusion.*

And there are, I think, the very best reasons for
concluding that in all the cases in which turbidity
has occurred after the organic mixtures have been
subjected to a heat of 140° F. (60° C.) and upwards,
this turbidity has been due, not to the survival of
the living units, but rather to the fact that the
mere dead organic matter of the inoculating com-
pound has acted upon the more unstable organic
infusions in a way which it was not able to do
upon the boiled saline fluids.

In order more fully to explain the grounds upon
which this conclusion is based, it will now be
necessary to recast the results of the 102 inocula-
tion experiments recorded in my last communica-

* See “The Beginnings of Life,” vol. ii., p. 2.

104 THE DEATH-POINT OF BACTERIA

tion.* They require to be thrown into a new
tabular form, in order to show how the results
differed amongst themselves when organic infusions
of different strengths were employed. The con-
sideration of this aspect of the question was
purposely delayed, in order to avoid the introduc-
tion of unnecessary complications into my last
communication, seeing that the conclusion which I
then sought to establish was in no way affected
by these facts.

NEUTRAL HAY-INFUSION.

Infusion of sp. gr. 1005. Infusion of sp. gr. 1002.
T Number| Date of /Resultsat the| Number, Date of |Results at the
Sere of Turbidity, |Expiration of of Turbidity, | Expiration of
rature. | Fexpts. if any. the 8th day. |!) Expts. if any. the 8th day
ie a j } 1 24 hours. Turbid. Por ie “ne
131° F. 6 48hours. | All turbid I 48 hours. Turbid.
140° F, rin 48 hrs. * rin 3 days. .
Moet 7 TEPER Latantia | = (hee Les turbid.
6 2in 5 days. |Three turbid
149° F. 4 \j xin 8 days. | One clear.
s° F.
(pe °C.) } 15 is All clear.
167 ee ao 4 a All clear.
Gere) \ 12 ie All clear.

« See Froceedings of the Royat Society, No. 143, p. 230.

AND THE CAUSES OF FERMENTATION. 105

Reference will be made to these Tables in the
setting forth of my reasons for the conclusion that

ACID TURNIP-INFUSION.

Infusion of sp. gr. 1008. Infusion of sp. gr. 1005.
Tempe-| Number] Date of /Resultsat the|/Number) Date of [Results at the
pa ae . of Turbidity, | Expiration of of Turbidity, | Expiration of
‘| Expts. if any. the 8th day. |} Expts. if any. the 8th day.
122° F, one ars ae aay oo OT
131° F. 5 24 hours. | All turbid. 2 48hours. | All turbid.
wor} 6 gohours, | All turbid. 6 { 233 or han turbid.
. rin 3 days. Four turbid.
149° F. 3 5 days. All turbid. 7 { rin 7 days. ¥
2 in 8 days, Three clear.
158° F. eae bis aan 17 ae All clear.
167° F, on on on 4 eee All clear.
176° F. ny) oes on tne ove an

the more or less delayed putrefaction which takes
place in inoculated organic infusions raised to the
temperature of 140° F., and to other degrees of heat
above this point, is due to the influence of the not-
living ingredient (4) of the inoculating compound.
These reasons are the following :—

1. Because the turbidity which has occurred in
inoculated organic infusions that have been subjected
to a temperature of 140° F. has always manifested

106 THE DEATH-POINT OF BACTERIA

itself appreciably later, and advanced much more
slowly than in similar mixtures which had not been
heated above 131° F.; whilst it has commenced even
later, and progressed still more slowly, when occurring
in mixtures previously heated to 149° F. Such facts
might be accounted for by the supposition that ex-
posure in these organic fluids to the slightly higher
temperature suffices to retard the rate of growth and
multiplication of the living units of the inoculating
compound, although the facts are equally explicable
upon the supposition that the later and less energetic
putrefactions are due to the sole influence of the
mere organic matter of the inoculating compound.

2. So far as the evidence embodied in the Tables
goes, it tends to show that the more unstable dif-
ferent specimens of similar infusions are (that is, the
stronger they are), the more rapidly and frequently
does late turbidity ensue, and the more this late
turbidity approaches, both in time of onset and in
rate of increase, to that which occurs when inoculated
infusions are not heated to more than 131° F.—when
both living and not-living elements of the inoculating
compound act conjointly as ferments. Such facts
show quite clearly that where the intrinsic or pre-
disposing causes of change are strong, there less
potent exciting agencies are more readily capable of
coming into play; but they still do not enable us

AND THE CAUSES OF FERMENTATION. 107

to decide whether the exciting cause of this delayed
turbidity is in part the living element whose vitality
and rate of reproduction has been lowered by the
heat or whether the effects are wholly attributable
to the mere organic matter of the inoculating com-
pound.

So far, therefore, we have concomitant variations
which are equally compatible with either hypothesis.
But it will be found that each of the three succeeding
arguments speaks more and more plainly against the
possible influence of the living element, and in favour
of the action of the organic matter of the inoculating
compound, as an efficient exciting cause of the de-
layed putrefactions occurring in the cases in question.

3. As stated in my last communication,* when
single drops of slightly turbid infusions of hay or
turnip previously heated to 140° F. are mounted and
securely cemented as microscopical specimens, no
increase of turbidity takes place, although drops of
similar infusions heated only to 122° F. do notably
increase in turbidity (owing to the multiplication of
Bacteria) when mounted in a similar manner. Under
such restrictive conditions as these, in fact, a drop of
an inoculated and previously heated organic infusion
behaves in precisely the same manner as a drop of
a similarly treated ammonic-tartrate solution. In

.* Loc. cit. p. 228 [p. 87].

108 THE DEATH-POINT OF BACTERIA

each case, when heated to 140° F., turbidity does not
occur, apparently because there are no living units to
multiply, and because in these mere thin films of
fluid dead ferments are as incapable of operating
upon the organic fluids as they are upon the am-
monic-tartrate solutions,

4. Because, in the case of the inoculation of fluids
which are-not easily amenable to the influence of
dead ferments, such as a solution containing ammonic
tartrate and sodic phosphate, this delayed turbidity
does not occur at all. Such inoculated fluids become
rapidly turbid when heated to 131° F., though they
remain clear after a brief exposure to a temperature
of 140° F. When the living units in the inoculating
compound are killed, there is nothing left to induce
turbidity in such solutions. The mere fact that these
fluids do not undergo change when exposed to the
air proves conclusively that they are very slightly
amenable to the influence of the ordinary dead
organic particles and fragments with which the atmo-
sphere abounds, The absence of delayed turbidity
in these fluids serves, therefore, to throw much light
upon the cause of its occurrence in the organic
infusions.

5. And, lastly, I can adduce crucial egdenee sup-
plied by the ‘Method of Difference, speaking with
its accustomed clearness. Two portions of the samc

AND THE CAUSES OF FERMENTATION. 109

hay- or turnip-infusion can be inoculated in such
a manner as to supply us with the information we
require. In the one case we may employ a drop
of a turbid ammonic-tartrate solution previously
heated to 140° F., in which, therefore, the living units
would certainly be killed; whilst in the other we
may add another unheated drop of the same turbid
saline solution to the organic fluid, and then heat
this mixture also to the temperature of 140° F.. The
comparative behaviour of these two inoculated fluids
(placed, in the ordinary manner, in previously boiled
corked phials) should be capable of showing us
whether the living elements of the inoculating com-
pound were able to survive when heated in the organic
infusion. If they did survive, the fluids inoculated
in this manner ought to undergo putrefaction earlier
and more rapidly than those inoculated with the drop
of turbid fluid, in which we know the Bacteria, |
Vibriones, and their supposed germs would have been
reduced to a state of potential death. With the view
of settling this question, therefore, the following ex-
periments were made: =

IIo

THE DEATH-POINT OF BACTERIA

Description of
Experiments.

Results.

Inferences.

A. Boiled ammonic-tar-
trate solution, inoculated
with an unheated drop of a
similar solution turbid with
Bacteria, &c.

B. Boiled ammonic-tar-
trate solution, inoculated
witha drop of a turbid saline
solution previously heated
to 140° F.

C. Boiled turnip-and-hay-
infusions, inoculated with a
drop of a turbid saline solu-
tion previously heated to
140° F.

D. Boiled turnip-and hay-
infusions, inoculated with a
drop of an unheated turbid
saline solution, the inocu-
lated fluid being sub-
sequently heated to 140° F.

E. Boiled turnip-and hay-
infusions, inoculated with a
drop of an unheated saline
solution, the inoculated fluid
being subsequently heated
to 140° F,

Turbid in 40 hours.

Clear at the expira-
tion of Sth day.

Turnip-infusions tur-
bid in 2} days.

Hay-infusions clear
at expiration of 8th
day.

Turnip-infusions tur-
bid in 24 days.

Hay-infusions clear
at expiration of 8th
day.

Turnip-infusions tur-
bid in 28 hours.

Hay-infusions turbid
in 38 hours.

That boiled ammonic-tar-°
trate solution is a fluid
inoculable by living Bac-
teria, &c., and favourable
for their growth and rapid |
multiplication.

That Bacteria, Vibriones,
and their supposed germs
are either killed or de-
prived of all power of
multiplication when heat-
ed to 140° F. in this fluid.

The precisely similar be-
haviour of the turnip-
and hay-infusions of
series C and series D re-
spectively shows that the
Bacteria, Vibriones,and
their supposed germs are
as inoperative in series
Das they are known to
be in series C; whilst
the behaviour of the hay-
infusions shows that they
are little amenable to the’
influence of the drop of
the saline fluid when its
living units are killed.

Shows that the heat of 131°
F. is not sufficient to kill
Bacteria, Vibriones, and
their supposed germs in
organic infusions, and,
again, that turnip-infu-
sions are more rapidly in-.
fluenced by such an inocu-
lating agent than some
hay-infusions.*

No experiments could speak more decisively. Those
of series B show that Bacteria, Vibriones, and their

* These experiments of series C, D, and E were many times repeated
with specimens of the same turnip- and hay-infusions, the specific gravity

of the former being about 1008 and that of the latter 1005.

Different

Specimens [of the material to be infused, and] of hay especially, vary so
much that it becomes absolutely essential to use portions of the same
infusion for the comparative experiments of these different series.

AND THE CAUSES OF FERMENTATION. II

supposed germs are either actually or potentially
killed when heated to 140° F. in the neutral saline
fluid, which the experiments of series A show to be
eminently favourable for their growth and reproduc-
tion. Being certain, therefore, that the living units
are killed in the drops with which the fluids of
series C were inoculated (because they were drops ot
the same fluid as was employed in series B), we may
be equally certain that the turbidity and putrefaction
which did ensue in the turnip-solutions of series C
were due to the influence of the mere dead con-
stituents of these drops of the turbid saline fluid;
whilst, seeing that the behaviour of the fluids of
series D was precisely similar to those of series C,
we have a perfect right to infer that this series of
fluids (D) was as devoid of living units as those of C
are known to be—that is, that Bacteria, Vibriones,
and their supposed germs are killed by the tempera-
ture of 140° F. in organic fluids, just as they are in
saline fluids, although, as shown by the experiments
of series E, they do not succumb to a heat of 131° F
These experiments of series C and D further illus-
trate the different degrees of amenability of different
organic fluids to the same dead ferments ; whilst the
comparison of the results with the hay-infusions of
series C and D with those previously cited (in which
the inoculating compound was a drop of an organic

112 THE DEATH-POINT OF BACTERIA

infusion heated to the same temperature of 140° F.)
will illustrate the different influence of dissimilar
dead ferments upon infusions of the same kind.

The evidence now in our possession shows, there-
fore, that whilst the temperature at which living fer-
ments cease to be operative varies within very narrow
limits (131°—140° F.),* that which destroys the virtues
of not-living ferments varies within much wider limits,
and depends not only upon the amount of heat
employed, but also upon the nature of the pu-
trescible or fermentable liquid to which such ferment
is added, in conjunction with the degree of heat and
other conditions to which the mixture is subsequently
exposed.t Here, therefore, we have evidence as to
the existence of a most important difference between
living and not-living ferments, which has always
been either unrecognised or more or less deliberately

* Liebig has proved that a temperature of 140° F, kills Zorula, and
always suffices to arrest a process of fermentation taking place under
their influence in a sugar solution. Zoru/z heated in water to 140° F.
also fail to initiate fermentation in a sugar solution. I have also found
that an exposure to a temperature of 131° F. for five minutes always
suffices to destroy the life of Desmids, Euglenee, Amcebx, Monads,
Ciliated Infusoria, Rotifers, Nematoids, and other organisms contained
in specimens of pond-water. All these lower organisms seem to be
destroyed at about the same temperature, as might have been expected
from the fundamental relationship which must exist between these several
varieties of the one substance—living matter.

+ See “ The Beginnings of Life,” vol. i., p. 437.

AND THE CAUSES OF FERMENTATION. 113

ignored by M. Pasteur and his followers.* This
difference is, moreover, thoroughly in accordance
with the broad physico-chemical theory of fermen-
tation which has been so ably expounded by Baron
Liebig and others, and the truth of which may now
be regarded as definitely established. According to
this theory ‘living’ matter, as a ferment, would take
rank merely as a chemical compound having a
tolerably definite constitution; and this, we might
-reasonably infer, would, like other chemical com-
pounds, be endowed with definite properties—and
amongst others that of being decomposed or radically
altered by exposure to a certain amount of heat.
Looked at also from this essentially chemical point of

* See, for instance, all M. Pasteur’s celebrated experiments in which
he had recourse to an ‘‘ ensemencement des poussiéres qui existent en
suspension dans V’air,” as recorded in chaps. iv. and v. of his memoir in
“ Ann. de Chimie et de Physique,” 1862, M. Pasteur was engaged in
an investigation one of the avowed objects of which was to determine
whether fermentation could or could not take place without the intervention
of living organisms, which M. Pasteur held (in opposition to many other
chemists) to be the only true ferments, In his inoculating compound
(dust filtered from the atmosphere), there was, as M. Pasteur was fully
aware, a large amount of what his scientific opponents considered not-
living ferment, whilst Zossidly there existed a certain number of living
ferments. In explaining the results of his experiments, however, M.
Pasteur and others thought he was pursuing a logical and scientific
method when he attributed these results to the action of the possibly
existing element of the inoculating compound, whilst he ignored alto-
gether the other element which was certainly present in comparatively
large quantity, and the testing of whose efficacy was the ostensible

object .of his research.
{

Il4 THE DEATH-POINT OF BACTERIA

view, it would be only reasonable to expect that the
molecular movements of living ferments with a
lowered vitality might not be more marked or
energetic than those which many not-living organic
substances are apt to undergo; and this being the
case, we might expect that there would often be a
great practical difficulty in ascertaining whether a
ferment belonging to the arbitrary and artificial
(though, in a sense, justifiable and natural) category
of “living” things had or had not been in operation.
It has, moreover, been most unmistakably proved
that the limits of vital resistance to heat which
Bacteria, Vibriones, and their supposed germs are
capable of displaying are essentially the same in the
three type fluids which I have employed—that is, ina
weak saline fluid, in a neutral organic infusion, and in
an acid organic infusion. No evidence exists really
tending to show that these organisms or their germs
are capable of withstanding the effects of heat better
in one of such fluids than in another. We may
therefore safely affirm that M. Pasteur never had any
valid evidence in support of his conclusion that the
germs of Bacteria and Vibriones can resist heat better
in neutral or slightly alkaline solutions than in slightly
acid mixtures. The experimental results which led
him to arrive at such a conclusion were not logically
capable of receiving any such interpretation, whilst

AND THE CAUSES OF FERMENTATION. IIS

they can be legitimately accounted for in accordance
with the broader physico-chemical theory of fermen.
tation, the truth of which has now been established.*
We may also safely afirm that M. Pasteur’s more
specific statement, to the effect that the germs of
some Bacteria and Vibriones are capable of resisting
the influence of a heat of 212° F. when in the moist
state, though they are killed by a temperature of
230° F., was a conclusion altogether unwarranted by
the evidence which he adduced. Finding that certain
fluids treated after the manner introduced by Schwann
always remained quite devoid of living organisms, M.”
Pasteur very legitimately concluded that pre-existing
organisms and germs had been killed during the
boiling of the liquid ; but finding that when a little
powdered chalk was added to fluids of the same
kind (which in all other respects were treated in a
similar manner) living organisms were after a time
invariably found to appear, although they as in-
variably failed to appear when the same fluids were
heated to a temperature of 230° F. (110° C.), two
equally legitimate provisional conclusions were open

* I attempted to show, nearly three years ago (see Mature, July 14,
1870, pp. 224-228), that the differences which M. Pasteur ascribed to
differences of vital resistance of organisms in particular fluids were just

as explicable in accordance with the physico-chemical theory of fermen-
tation, by reference to the different degrees of fermentability of the

«

several fluids,
> I 2

116 THE DEATH-POINT OF BACTERIA

to M. Pasteur in explanation of these facts. What
did M. Pasteur do? Following the same method as
he had formerly employed,* he again ignored one of
the equally possible interpretations, and unsuccess-
fully attempted to prove, by a repetition of similar
reasoning,t that the different results in the two
series of experiments were due to the fact that the
germs of Bacterta and Vibriones which had been
killed by the temperature of 212° F. in the first series
were not killed by this temperature in the second
series (in which a slightly alkaline fluid had been
employed), although they were destroyed by the
higher temperature of 230° F. Thus results which
were due to the action of not-living ferments
were ascribed to living ferments, and the possible
action of not-living ferments was ignored, although,
as I have said before, the ostensible object of M.
Pasteur’s researches was to inquire into the relative
importance of not-living and living ferments, or
whether, in fact, ‘dead’ substances (in the ordinary
acceptation of the word) could act as ferments.
When viewed from the stand-point of the physico-
chemical theory of fermentation, the apparently
contradictory results arrived at by the same experi-
menter at different times or by different experi-

* See note ~ on page 113.
+ See “Ann, de Chim. et de Phys.” 1862, pp. 60-65.

AND THE CAUSES OF FERMENTATION. 117

menters, in this line of research, cease to be the
inexplicable puzzle which they must always appear to
those who place implicit faith in the narrower and too,
exclusive ‘vital’ theory of fermentation advocated.
by M. Pasteur and his followers.

My investigations have convinced me that, with
regard to degree of fermentability, the various fer-
mentable fluids and mixtures are divisible into three
distinct subclasses :—

I. There are what may be called self-fermentable
* fluids or mixtures—that is, fluids or mixtures which,
after exposure to a temperature of 212°F. or higher,
are still capable of undergoing fermentative changes
without the addition of less-heated matter, either not-
living or living. The changes occurring in these self-
fermentable fluids (in which pre-existing living things
have been killed), when strictly protected from contact
with adventitious particles, vary in rapidity and
in intensity from the highest to the very lowest
degrees of fermentability. These gradations are de-
pendent principally upon the nature of the fluids or
mixtures employed, and upon the degree of heat to
which they have been submitted, though partly also
to the temperature, pressure, presence or absence of
filtered air, and degree of light to which the mixtures
are subsequently exposed. For the sake of conveni-
ence, these gradations may be ranged into several

118 THE DEATH-POINT OF BACTERIA

distinct groups, though of course any such divisions
as I am now about to sketch are purely artificial and
are connected with one another in nature by innumer-

able transitions,

Nature of Fluids.

A. Turnip-infusion with cheese,
turnip - infusion neutralized by
liquor potasse, ordinary turnip-
infusion, strong hay-infusion, &c.

B. Turnip-infusion neutralized
by liquor potassze, ordinary turnip-
infusion, ordinary hay-infusion,
&e,

C. Beer-wort,* &c.

D. Weak hay-infusions, urine,
solutions containing ammonic car-
bonate and sodic phosphate with
minute organic impurities, &c.

Nature of Results.

Within two to four days marked
turbidity, owing to the appear-
ance of swarms of Bacteria and
Vibriones. Fluids more or less
foetid. (Putrefaction.)

No uniform turbidity, but growth
of flocculi in a more or less clear
liquid. After a time the flocculi
(composed of aggregated Bac-
teria and Vibriones) gradually
subside, and the activity of the
process ceases. Fluids either
foetid or having a mere sour
odour.

Fluids which become more or less
‘uniformly and rapidly turbid,
owing to the appearance of
swarms of Zorula,

Do not become visibly turbid or
produce visible flocculi, although
on microscopical examination
they may be found to contain
living Bacteria pretty uniformly
distributed, but in comparatively
small quantities. The odour is
often not more appreciably
altered than the clearness of such
solutions.

* Ihave had no experience with such a fluid myself. M. Pouchet’s
observations were, however, most striking on this subject (see his ‘‘ Nou-
velles Expériences,” Paris, 1864, p. 190).

AND THE CAUSES OF FERMENTATION. 119

Nature of Fluids.

E. Weak hay-infusions, urine,
solutions containing ammonio-cit-
tate of iron and minute organic
impurities,* &c,

F. Solutions of ammonic tar-
trate and sodic phosphate with
minute organic impurities, &c,

G, Weak or strongly acid in-
fusions, and also many saline so-
lutions containing organic impuri-
ties. :

Nature of Results.

Same as in the last group, + though
after weeks or months a dirty-
looking sedimentary matter
slowly accumulates at the
bottom of the flask, which on
microscopical examination is-
found to be composed partly of
Bacteria with Vibriones and
Lepiothrix, and partly of Tor-
ule or more thickly-walled fun-
gus-germs.

Same as in the last group, only
the dirty sedimentary matter
which accumulates never con-
tains either Bacteria, Vibriones,
or Leptothrix. Living Torule
and thick-walled fungus-germs
in various stages of formation
are frequently met with, ard
also, occasionally, a mycelium
resulting from the development
of some of these bodies.

May remain permanently barren,
and never show any traces of
organisms either dead or living.t

* In solutions containing iron, green organisms may subsequently be
found (see ‘‘ Beginnings of Life,” vol. ii. p. 157).
+ This, in fact, is in many cases the kind of ehange which the fluids

a described ultimately undergo.

t See many negative experiments recorded in ‘‘ The Beginnings ot

Life,” vol. i. ch. xi.

Mr. W.N. Hartley has laboured very indus-

triously to disprove something which I never asserted (see Proceedings
of Royal Society, vol. xx. p. 140). In my early paper in Mature, I
expressly stated that organic impurities were always present in the
saline solutions which I employed ; and, as may be seen by the note
appended to the conclusions of that paper, I never claimed to have

120 THE DEATH-POINT OF BACTERIA

II. To the second subclass belong fluids which,
after exposure toa temperature of 212°F. or higher,
may be kept clear or apparently unaltered so long as
they are shut off from contact with unheated atmo-
spheric or other organic particles, but which do under-
go putrefaction, or more or less marked fermentation,
soon after they are brought into contact even with
mere not-living organic matter.

The experiments recorded in this communication
have most conclusively proved the efficacy of not-
living organic matter as a ferment or inciter of change
in previously barren fluids. And combining the know-
ledge derived from these experiments with that which
we pow possess concerning the absence of living
Bacteria, Vibriones, and their germs in the air, to-
gether with the known prevalence of minute organic
particles and fragments of various kinds, the explana-
tion of M. Pasteur’s celebrated experiments in which

established that living organisms could appear in saline solutions free
from traces of organic impurity. Mr. Hartley did attempt to work with
approximately pure saline solutions, and in other respects also the con-
ditions of his experiments differed so much from mine, that the results
which he obtained could not possibly be considered to disprove what I
had previously stated. Some of his flasks were heated to 180° C., a
temperature about which I had said nothing; and whilst his organic
infusions were too weak, some of his saline solutions were too concen-
trated, though the strengths of others were not given at all. Fluids
were also employed (such as urine, heated to 130° C.) which I had not
made use of, and which I should not have thought of experiment-
ing with.

AND THE CAUSES OF FERMENTATION. 121

he had recourse to an “ensemencement des poussiéres
qui existent en suspension dans lair,” becomes quite
easy and legitimate without having recourse to the
hypothesis of Panspermism.* Now, also, are we
enabled to understand all the apparent inconsistencies
of those experiments in which previously boiled fluids
have been exposed to the ordinary air of different
localities, and have then been resealed. If many
specimens of these fluids remained unchanged, whilst
others, after a few days, swarmed with Bacteria and
Vibriones, we may now very safely attribute these
previously puzzling results to the comparative absence
or presence of organic fragments in the particular
volumes of air which chanced to get into the flasks,
and to the different nature of the fluids employed by
different experimenters.

Many of the fluids which habitually remain clear
after a previous ebullition in flasks whose necks have
been plugged with cotton-wool, many times bent, or
hermetically sealed after the entry of calcined air, or
when enclosed in vessels which are completely full
(in Gruithuisen’s fashion), belong to this subclass, In

* See the experiments before alluded to, which are recorded in
chaps. iv. and v. of his Memcir.

+ See M. Pasteur’s Memoir, chap. vii, and also Compt. Rend.,
Nov. 5, 1860. See also a record of other experiments made with the
air of alpine regions by MM. Pouchet, Joly, and Musset, in Comgzt,
Rend., Sept. 21, 1863.

122 THE DEATH-POINT OF BACTERIA

’

other cases, however (as in many of those instances
where urine or hay- or turnip-infusions have been
employed), those who do not content themselves with
a mere naked-eye inspection of the apparently pure
fluids would find on microscopical examination of the
sediment that such fluids were to a low degree self-
fermentable—that they correspond, in fact, with group
E of the last subclass;* whilst, in addition, my re-
searches have shown that many of such fluids are
capable of being rendered self-fermentable to a
marked degree, if, instead of subjecting them to
contact with calcined air or variously filtered air, its
reflux after ebullition is altogether prevented by her-
metically sealing the neck of the flask during ebullition.
Operating in this way, I have repeatedly found that
fluids freed from the pressure of air and from its in-
fluence altogether, become to a marked extent self-
fermentable, although the same fluids exposed to
filtered or calcined air under ordinary atmospheric
pressure remain unaltered and barren, or at most
exhibit the very low degree of fermentability referred

* Other fluids richer in organic matter or otherwise more favourably
endowed, instead of presenting this low degree of self-fermentability, are
notably prone to undergo change when we attempt to preserve them in
the manner described, although such modes of preparation do suffice for
preserving so many fluids, This has been fully admitted by Schroeder
and Dusch, Schwann, Pasteur, and others,

AND THE CAUSES OF FERMENTATION. 123

to as characterizing group E.* But just as amongst
the self-fermentable fluids we find there are some
which only engender Zorule or other allied fungus-
germs, so now we find that some previously boiled
fluids, even when fully exposed to the air, swarm only
with Torule. Those exciting agents derived from the
atmosphere which, with one set of fluids, initiate
changes leading to the evolution of Bacteria, with
another set lead only to the evolution of Zorule.
And whilst telling us that the Bacteria which appear
in previously barren fluids after exposure to air are
not due to their contamination with germs of Bacteria,
some observers would have us conclude that the Torule
which appear in other previously barren fluids after a
similar exposure are the products of preexisting aérial
germs of such organisms. This conclusion, however,
cannot readily be accepted in the face of the evidence
derived from the closed-flask experiments with self-
fermentable fluids of the lowest degree.f Such experi-
ments, in fact, render the hypothesis as to the wide-
spread distribution of aérial germs of Torul@ wholly
unnecessary, by showing that certain fluids, by reason

* In illustration of this statement see ‘‘The Beginnings of Life,”
Appendix C, Exps, viii., ix., xiv., xv., xviii., XX., XXVi., XXX., XXxlii,
and xxxvi.

+ The only evidence in favour of such a conclusion is not one jot
more conclusive than that which was formerly adduced in favour of the
universal prevalence of Bacterta-germs in the air.

124 THE DEATH-POINT OF BACTERIA

of certain intrinsic peculiarities, when they undergo
fermentation give rise to Zorule only. We are thus
led to conclude that whilst some fluids are capable of
engendering both kinds of organisms, others tend only
to produce one or other of them—whether the fluids
are contained in closed flasks or in open vessels ex-
posed to the incidence of atmospheric particles. I
have more than once seen nothing but Zorule appear
in an infusion of turnip exposed to the air after it had
been heated in a closed tube to a temperature of 293°F.
for twenty minutes, and I have once seen the same
thing occur in an unheated infusion of turnip exposed
to the air, though on all other occasions such infusions
have swarmed only with Bacteria and Vibriones. On
the other hand, a boiled ammonic-tartrate solution ex-
posed to the air, though protected from an excess of
atmospheric particles (for the advent of a large number
of these might in some cases incite putrefaction), is
never found to contain Bacteria ; the fluid continues
clear, though a sediment gradually accumulates at the
bottom of the flask, amongst which Toru/g and other
fungus-germs are constantly to be found—more nu-
merous though otherwise very similar to those which
are to be met with in flasks closed during ebullition,
or in others to which only filtered air is admitted.
Although Zorule only appear in such fluids, they
continue all the time to be eminently inoculable by

AND THE CAUSES OF FERMENTATION. 125

Bacteria ; and, again, when the Toru/e begin to decay
they are apt to incite a more or less manifest putre-
faction, during. which the fluid gradually becomes
turbid with Bacteria. It is, in fact, a general rule
that putrefaction is apt to supervene upon a fermenta-
tion of a more smouldering type.

III. In the third subclass I include fluids which,
after exposure to 212°F. or higher temperatures, are
unable, either alone or under the influence of ordinary
atmospheric particles or fragments, to undergo putre-
faction, although such a process can invariably be
initiated by bringing the fluids into contact with
living ferments. As example of such fluids, I may
‘cite the neutral saline solution to which I have so
often referred and that known as Pasteur’s solution.
Other fluids of the same kind have lately been re-
ferred to by Professor Huizinga.** The fact that
certain fluids cannot be made to undergo putrefac-
tion by the influence of dead organic particles, al-
though they become at once amenable to the influence
of living units, unmistakably shows the superior
potency of living ferments; their action has, more-
over, invariably proved to be certain and inevitable in
all the cases in which they were known to be present.
Even these least fermentable fluids of our third sub-
class invariably become turbid within three days after

* See Nature, March 20, 1873, p. 380.

126 THE DEATH-POINT OF BACTERIA

inoculation with living units, if maintained at a tempe-
rature of about 70°F,; whilst when other more change-
able fluids are inoculated, putrefaction ensues with
equal certainty, though with much greater rapidity.

What we have learned, therefore, concerning the
invariable uniformity of simple inoculation experi-
ments should of itself teach us how difficult it would
be to account for cases of delayed putrefaction, or for
cases in which a mere smouldering fermentation is set
up, by the old though now well-nigh exploded notion
of contamination by preexisting germs. Where
living ferments really exist, the course of events is
definite and almost invariable in its rapidity; but
where fermentation takes place as a result of chemical
changes occurring in the fluid itself (either by its own
unaided powers, or under the stimulating influence of
a less-heated organic ferment) there is abundant room
for all the irregularity and variation actually en-
countered. These cases of irregularity and variation
have always, on other grounds, defied all legitimate
attempts to bring them individually within the pale
of a narrow and exclusively ‘vital’ theory of fer-
mentation ; and now a wider experience with living
ferments equally tends to show the impossibility of
legitimately explaining a great mass of irregular
phenomena by means of agents whose action is shown.
to be constant and almost invariable.

AND THE CAUSES OF FERMENTATION. 127

Thus it can now be proved, by evidence of a most
unmistakable nature, that the process of putrefaction
which invariably occurs in previously boiled putres-
cible infusions contained in flasks with narrow but
open necks is not commonly (is, perhaps, only very
rarely) initiated by living germs or organisms derived
from the atmosphere; it can also be proved that
putrefaction and the appearance of swarms of living
organisms may occur in some boiled fluids when they
are simply exposed to air which has been filtered
through a firm plug of cotton-wool or through the
narrow and bent neck of a flask, to air whose particles.
have been destroyed by heat, or even in fluids her-
metically sealed in flasks from which all air has been
expelled. The evidence in our possession is therefore
most complete on this part of the subject: it shows
beyond all doubt, not only that putrefaction may and
does very frequently occur under conditions in which
the advent of atmospheric particles, whether living
or dead, is no longer possible, but also that living
particles derived from the atmosphere can only be
very rare and altogether exceptional initiators of the
putrefaction which invariably occurs in previously
boiled infusions exposed to the air.

Again, the evidence which we now possess with
reference to the influence of heat upon Bacteria,
Vibriones, and their supposed germs is no less deci-

128 THE DEATH-POINT OF BACTERIA

sive. It has been unmistakably proved that such
organisms and their imaginary germs are either
actually or potentially killed by a brief exposure to the
temperature of 140° F. when in the moist state; and
it had also been previously established that they are
invariably killed by desiccation even at much lower
temperatures.*

But if living germs do not come from the air to
contaminate the previously boiled fluids, and if it is
not possible for any of them to have escaped the des-
tructive influence of heat in the boiling fluid or on
the walls of the vessel in which the fluid is contained,
what can be the mode of origin of the swarms of
living things which so rapidly and invariably appear
in such infusions when contained in open flasks, and
which so frequently appear when the infusions are
contained in flasks whose necks are closed against

* See the experiments and conclusions of Dr. Burdon Sanderson in
Thirteenth Report of Med. Officer of Privy Council, p. 61. This fact
of the inability of these organisms and their germs to resist desiccation
shows the futility of some objections which have been from time to time
raised by those who thought that Bacteria, Vibriones, and their germs
might resist the destructive influence of heat (by adhesion to the glass
above the level of the fluid, or even in the fluid itself), just as dried and
very thick-coated seeds have been known to do. Dry heat would seem
to be even more fatal to such organisms and their germs than a moist
heat of the same degree, owing to their extreme inability to resist
desiccation : if they become dry they are killed at a temperature of
about 104° F., whilst if they remain moist they succumb, as we have
seen, to a temperature of 140° F.

AND THE CAUSES OF FERMENTATION. 129

atmospheric particles of all kinds? They can only
have arisen’ by the process which I have termed
Archebiosis.

Conclusions..

If a previously boiled ammonic-tartrate solution
remains free from Bacteria and Vzbriones when ex-
posed to the air, it is because the air does not contain
living organisms of this kind or their supposed
‘germs,’ and’ because mere dead: organic particles are
not capable of initiating Putrefaction in such a fluid.

‘And if ordinary organic infusions previously boiled
and exposed to the air do rapidly putrefy though
some of the same infusions when exposed only to
filtered air remain pure, it is because such fluids are
in the absence of living units, quite amenable to the
influence of the dead organic particles which the air
so abundantly contains, although they are not self-

Sh

fermentable.

Whilst if other more changeable fluids, after
previous boiling, when exposed to filtered air or cut
off altogether from contact with air, do nevertheless
undergo Putrefaction or Fermentation, it is because
these fluids are self-fermentable, and need neither
living units nor dead organic particles to initiate
those putrefactive or fermentative changes which lead

to the evolution of living organisms.
K

IV.
THE DESTRUCTIVE INFLUENCE OF

HEAT UPON LIVING MATTER.

WATER is boiling merrily over a brisk fire, when
some luckless person upsets the vessel, so that the
heated fluid exercises its scathing influence upon an
uncovered portion of the body—hand, arm, or face.
Those who have seen much of the effects produced
upon the human skin by such accidents, will have
acquired information not unworthy of influencing
their opinion on some more general problems con-
nected with the action of heat upon living matter.
Here, at all events, there is no room for doubt. Boil-
ing water unquestionably exercises a most pernicious
and rapidly destructive action ‘upon the living matter
of which we are composed. There is no need ta
appeal to the sufferer’s sensations for this information.
This, indeed, is a point of view which we may for the
present dismiss. For however agonizing these sensa-
tions may be, they could only supply us with infor-
mation upon a collateral point with which we are not
at present concerned. Apart from’ such subjective
effects there are objective effects. That is, we are

134 THE DESTRUCTIVE INFLUENCE OF

casily able to see the changes produced by boiling
water upon living matter—revealing themselves as
they do by an immediately altered appearance of the
skin, and by the terrible wound so quickly produced.
Upon these distressing, though, unfortunately, only
too familiar consequences of the action of heat upon
living matter, it is not necessary for me further to
dwell; I would merely have the reader so far bear
them in mind that they may not be incapable of
recall during the perusal of this article. The oc-
casional revival of such impressions may perhaps
prove a little instructive to those who chance to be
at all dubious as to the destructive effects of boiling
water upon lower organisms.

Probably, however, some of my readers may
already be possessed by the notion that the dis-
astrous effects just referred to are consequences
following rather from the fact of the high organiza-
tion of man’s tissues than from any intrinsic incom-
patibility of nature between living matter and boiling
water, The thought is natural enough and not un-
justifiable. On the other hand, it will not do to
attach much importance to it. Let us for a moment
consider the effects produced upon an ordinary hen’s
egg by a brief immersion in boiling water. Here we
have the ‘white,’ composed of albumen similar to
that which enters so largely into the composition of

HEAT UPON LIVING MATTER. 135

living tissues, turned from a clear fluid into an
opaque solid ; and we have the ‘ yelk, made up of a
dense aggregation of the simplest living units, also
more or less solidified. In spite of the investing
calcareous shell, these very obvious and: destructive
effects can be produced upon this large egg or ‘germ’
by an exposure for three or fourr minutes: to the in-
fluence of boiling water. Yet: the living matter in
this case is so simple that it possesses next to no
organization—it is so little vitalized that it can
only be considered to be half alive.

The conclusion would seem, therefore, to force itself
upon us that there is something intrinsically dele-
terious in the action of boiling water upon living
matter—whether this living matter be of high or
of low organization.

This subject is one of great importance in many
respects, so that it may repay us to look into the evi-
dence bearing upon it with some degree of care. It
-is of great practical importance, for instance, in refer-
ence to the process of disinfection by heat, where we
have to do with articles of furniture or wearing ap-
parel used by a person suffering from a contagious
disease. Because, in such a case, what we ought
undoubtedly to know is whether the temperature of
boiling water, or even some lower temperature,

136 THE DESTRUCTIVE INFLUENCE, OF

suffices to kill any living particles which may act as
so-called ‘germs of disease.’ This is a subject upon
which there should be no room for doubt. Again,
from a purely scientific point of view, the question is
of equal cogency because of its bearing upon one of
the most momentous problems in biological science—
namely, that of the Origin of Life. It is on this
latter account, more especially, that I now take up the
inquiry as to the grade or degree of heat which proves
destructive to different kinds of living matter.

A preliminary word of explanation, therefore, must
be given concerning the bearings of this question
upon the Origin of Life problem.

It is at present very generally admitted, upon the
strength of well-known .experiments, that living
matter will appear and grow rapidly in hermetically
sealed flasks containing certain fluids after the flasks
and their contents have been thoroughly raised to the
temperature of boiling water for ten minutes or more.
These experiments we may mentally label as Series
A. Other experiments, which we may similarly label
Series B, had also shown that a brief exposure in the
moist state to a temperature considerably below the
boiling point of water, is destructive to all kinds of
living matter submitted to its influence. The experi-
ments of Series A, therefore, taken in conjunction with
those of Series B, must (if the latter results are as

HEAT UPON LIVING MATTER, 137
’ S

reliable as the former) be held to prove that living
matter can originate independently, or de xovo,
through the mere productive properties of certain
infusions or solutions.

If the facts are true, is it possible to stave off the
conclusion? Whilst the candid reader is asking him-
self this question, I may further point out to him that
as the previously discredited results belonging to
Series A are no longer denied, doubt is now only
possible upon a subject hitherto supposed to be
settled—namely, as to whether living ‘matter is really
killed by exposure in the moist state to a tempera-
ture of 212° F. Obviously, at such a juncture, it
rested more especially with those Panspermatists who
chose still to be opponents of ‘spontaneous genera-
tion, to show that this belief concerning the de-
structive efficacy of boiling water, upon the truth of
which they had previously relied, was erroneous—
seeing that the advocates of spontaneous generation
had demonstrated the truth of their position with
reference to the experiments of Series A. Should the
Panspermatists fail to:produce this evidence as to the
untruthfulness of their-old view, they must not expect
to hear that they have the best of the argument; and
still less will they be able to hold their ground if,
whilst abstaining themselves from all experiments
belonging to Series B, their scientific opponents do

138 THE DESTRUCTIVE INFLUENCE OF

make careful investigations in this direction, and
arrive at the conclusion; that not only was the old
opinion right as to the destructive action of boiling
water, but that living matter unaccustomed to the
influence of heat is killed. by a brief exposure even
to the much lower temperatnre of 140° F.

Such being the present aspect of the problem,
those most interested in it may remember that know-
ledge would not advance in the rapid way which it does,
were it not for the fact that the difficulties of one
generation of menioften disappear before the clearer,
because more unprejudiced, vision of the next. Grow-
ing gradually more.familiarized with the facts, those
who come after us will be more and more influenced
by them, and at the same time less warped by theo-
retical considerations already out. of harmony with
our present state of knowledge: I.may perhaps be
allowed to use the words-of Mr. Darwin and say with
him: “I look with: confidence to the future,—to
young and rising naturalists, who will be able to view
both sides of the question with impartiality.” We
are now in a state of transition. We are gradually
learning to accept the:doctrines of Evolution, as ap-
plicable to different departments of knowledge, though,
as is so frequently the.case when new doctrines are
being adopted, the transition is effected by many in

a partial manner—they, unconsciously, perhaps, en-

HEAT UPON LIVING MATTER.. 139

deavour to make a sort of compromise, trying to
retain some of their most deeply-rooted convictions
and mix them harmoniously with new views. Me-
tallic mercury, however, will not mix with water, and
it will be found that there is a similar incompati-
bility between the explanations of the Pansperma-
tists and our present state of knowledge in regard to
the question of the Origin of Life.

It remains for me now, therefore, to. trace the
different steps by which we have arrived at our
present knowledge concerning the destructive effect
of Heat upon Living Matter. And, to do this effec-
tually, I must refer my readers to good work done in
the latter third of the last century by the acute and
learned Abbé Spallanzani, whilst he was engaged in
promulgating Panspermatist doctrines in opposition
to the views of our countryman Needham, who, in
those days, steadfastly proclaimed the. truth and
reality of ‘spontaneous. generation’—though the
philosophical doctrines. by. which he was influenced
caused him to limit the-acceptation of the phrase to
what we now understand. by the term Heterogenesis.

I refer first of all to the work of Spallanzani, partly
because he alone, of all thase who have adopted
Panspermatist views and. have. taken part in this
controversy, has fairly and. fully faced the question

140 THE DESTRUCTIVE INFLUENCE OF

of the degree of heat which proves fatal to various
living things, by making it the subject of direct
investigation. Others who have since defended
similar views (including Pasteur in France, and
Huxley and Sanderson in this country) have not
made the thermal death-point of living matter a
special subject of investigation, and have more or
less distinctly confounded the issues of this question
with that of the cognate though really distinct pro-
blem, as to whether certain infusions could them-
selves prove mother liquids and give independent
birth to living matter. Dire confusion has thus been
produced. A problem of a very simple nature has
been made to appear very complex, whilst those who
are able clearly to understand the real nature of the
question at issue are left to marvel why the followers
of Spallanzani have never ventured frankly to deal
with the question of the limits of ‘vital resistance’
to heat, as Pouchet termed it. Certainly they
have displayed, to say the least, a strange slug-
gishness in reference to this exceedingly important
problem.

But apart from the fact that no Panspermatist, or
declared opponent of spontaneous -generation, since
the time of Spallanzani has fully and directly experi-
mented upon the subject, I am all the more induced
to call the reader's attention to the Abbe’s treatment

HEAT UPON LIVING MATTER. 141

of it because, with some few exceptions, his investi-
gations were conducted in a manner which cannot be
improved upon at the present day, and because his
reasonings in reference to them are characterised by
great sagacity and fairness—allowance being made
for the actual state of knowledge in his time. The
work of the learned Abbé to which I shall especially
refer is entitled in the admirable French translation
by Jean Senebier, “ Opusclues de Physique Animale et
Végétale,’ the translation itself having been published
at Geneva in 1767.

Reflecting upon the import of experiments of his
own that he had just recorded, in which living organ-
isms were found in closed vessels containing infusions
of certain vegetable seeds after these closed vessels had
been immersed in boiling water for half, or, in some
cases, nearly three-quarters of an hour, Spallanzani
frankly avows * that if the first of the new organisms
had not come into being by some such independent
method as that suggested by, Needham, they must
have appeared either because certain ‘germs’ fron
which they had been derived had been able to resist
the destructive influence of boiling water for nearly
three-quarters of an hour, or because, after the cool-
ing of the closed vessels, some of the organisms
observed had passed from the air through certain

* Loc. cit. p. 48.

142 THE DESTRUCTIVE INFLUENCE OF

imaginary pofes in the glass. At the first glance
these seemed, as he says, “ deux suppositions égale-
ment impossibles, ou du moins trés difficiles 4 conce-
voir.” For very excellent reasons, not difficult for
the reader to imagine, the Abbé then points out that
the latter hypothesis, at all events, is entirely unte-
nable. The question thus became one of the simplest
description. If no good reason could be found in
support of the seemingly improbable supposition that
the experimental results referred to were to be ac-
counted for by a survival of germs, then, as he
confessed, he must admit the fact of an independent
and germless origin of living things. Whilst, if on the
other hand, it should appear probable that germs or
reproductive particles of living things could survive
the influence of such a prolonged immersion in boiling
fluids, he would not feel at all bound (on the strength
of his previous experiments) to believe in the indepen-
dent origin of living matter. This simple issue was
fully realized by Spallanzani, and acting in accordance
with the most obvious of scientific principles, he care-
fully sought for fresh evidence by means of well-
directed experiments, in order to guide him towards
a conclusion as to whether germs of living things
could or could not have resisted the action of boiling
water for more than half an hour.

He appreached the question in the following

HEAT UPON LIVING MATTER. 143

manner :—“ Can one,” he savs, “find any proof
sufficient to banish, or, at all events, to diminish one’s
natural repugnance to admit that the germs of ani-
malcules of the lowest order have the power of
resisting the action of boiling water? In reasoning
from the germs or eggs of animals with which we are
acquainted, would it be difficult for us to imagine
animalcules having this peculiarity ? It is true that
we are not acquainted with any eggs endowed with
such properties. I have already considered this
subject in the ninth chapter of my Dissertation.
1 there show how several kinds of eggs of insects—
not to speak of eggs of birds—perish under a heat
less than that of boiling water. I have shown also
that the seeds of plants are destroyed when they are
exposed to the heat of boiling water, and that even
those whose outer coat is of the hardest description
are not thereby spared.” But he goes on to say, as
he had only been able hitherto to make his observa-
tions on a limited number of eggs and seeds, there
was the chance that more extended observations
might reveal some capable of resisting this generally
destructive influence. He says he had never lost his
hope—with regard to seeds more especially—since
he had seen a statement by Duhamel to the effect
that some grains of wheat had germinated after
having been heated in a stove to a temperature above

144 THE DESTRUCTIVE INFLUENCE OF

the boiling point of water.** And as there is a con-
siderable resemblance between seeds and eggs, Spal-
lanzani was led to hope that something of the same
alleged extraordinary capacity for resisting heat
might be possessed by the eggs or germs of such
organisms as make their appearance in previously
boiled fluids. He was therefore stimulated to under-
take fresh observations upon eggs and seeds generally,
with the view, on the one hand, of ascertaining the
precise temperature which proved fatal to each kind,
and, on the other, of finding out whether these eggs
or seeds were capable of resisting a greater degree of
heat than the several animals or plants to which they
belonged.

This latter part of the inquiry was rightly deemed
by Spallanzani to be of great importance and capable
of affording him much guidance towards the proper
interpretation of his other experiments. He had
already determined that the lower Infusoria them-
selves are killed at a temperature of 34° Réaumur, or
108$° F.; and now having found that such organisms:

* Heated in all probability in the dry state. But it is well known
that seeds and desiccated animals can resist the influence of heat much
better in the dried state than when they are thoroughly moistened and
then heated, and it is as to the effects of heat upon living matter under
the latter conditions that we are at present concerned. For this reason,
therefore, I shall not dwell upon certain other experiments of Spallan-

zani, in which he heated seeds in the midst of dry sand—they lie
outside the houndaries of our present inquiry.

HEAT UPON LIVING MATTER. 145

would appear within closed vessels previously sub-
jected to a temperature of 212° F. (owing, as he was
inclined to think, to a survival of their germs), Spal-
lanzani was anxious to ascertain whether the differ-
ence in the capacity of resisting heat, imagined to
exist in this case between parents and germs, could
be justified by the establishment of similar differences
in heat-resisting capacity between other parent organ-
isms and their germs.

In carrying out these inquiries, Spallanzani adopted
the following method: * He placed the eggs, seeds or
organisms, made use of in his experiments, in a vessel
containing cold water, into the upper strata of which
was immersed the bulb of a thermometer. The
water was then heated slowly, and when the thermo-
meter indicated that the temperature had been
attained whose effect it was desired to test, the eggs,
seeds, or organisms were at once withdrawn and
placed, under suitable conditions, in a separate
vessel where their subsequent fate could be watched.
The effects of different grades of heat upon the ob-
jects experimented with were thus estimated, and the
temperature in successive trials was mostly made to
differ from that last employed by 5°R., or about
11°F. Operating in this way, and, in the case of eggs
or seeds, subsequently taking great care to place

* Loe. cit., p. 53.
L

146 THE DESTRUCTIVE INFLUENCE OF

those used in the different trials, under similar con-
ditions, alike favourable for germination or develop-
ment, Spallanzani obtained the following results :—

Of Frogs’ eggs only an extremely small number
developed after having been simply raised to the
temperature of 131° F., whilst not one developed
which had been heated to 145° or upwards. The
effects of intermediate temperatures were not tried,
and consequently the precise death-point was not
ascertained. The chances are, however, more in
favour of its being under than over 140° F. Tadpoles
produced from similar eggs all perished at 111°, and
the same temperature likewise proved fatal to the
parent Frogs from which the eggs had been derived,
as well as to aquatic Salamanders and to some Fish
with which experiments were made.

Silk-worms’ eggs, and the eggs of the Elm-moth
(Papillon de Orme), developed less and less fre-
quently when successive batches were heated to
temperatures approaching 144}°. When they were
actually submitted to this heat all perished, though
the highest temperature followed by development is
not recorded. Silk-worms themselves, as well as the
caterpillars of the Elm-moth, were uniformly killed
as soon as the water in which they were immersed
attained 108}°.

Eggs of the common Blow-fly only developed in

HEAT UPON LIVING MATTER. 147

very small numbers when raised to the temperature
of 135°, whilst all perished at 140°. The larve reared
from these eggs all died, as those of the silk-worm
and Elm-moth had done, as soon as the temperature
of the water rose to 1084°. Other adult larve of the
same species with which experiment was subse-
quently made perished at the same heat.

In addition, Spallanzani experimented with certain
aquatic organisms, though he was unable to discover
their eggs, and consequently was unable to make
experiments as to their power of resisting heat.
Thus he found that Leeches perished at 111°, and
the Nematoids known as “Vinegar Eels” at 113°.
Other aquatic Worms were killed at 111°, whilst
Water Fleas died at 107°.

So far, therefore, Spallanzani’s results were most
uniform : the different kinds of eggs were killed by
mere momentary exposure to a temperature of about
140° F,, whilst the animals to which they were related
perished at or about 110°.

The Abbé next turned his attention to the power
possessed by plants and their seeds of resisting the
action of heated water. These observations were
conducted in the same manner, though only the roots
of the plants were immersed in the water whilst its
‘heat was being raised. The plants with which ex-
periment had been made were afterwards carefully

L2

148 THE DESTRUCTIVE INFLUENCE OF

replaced in earth. Much care was also taken when
the seeds were sown to keep the batches distinct
from one another, and to place them as much as
possible under the influence of similar conditions.

Spallanzani’s first experiments were made with the
seeds of the Chick-pea, Lentil, Wheat-grass, Flax,
and Clover. The water was heated slowly, and the
seeds were taken out as soon as the desired tem-
perature was attained, so that there was only a
momentary exposure to the temperatures about to be
cited. Of those which had been.exposed to 190° F.
many did not germinate ; still fewer of the seeds that
had been exposed to 201° produced young plants,
whilst of those heated to 212° not one germinated.
After the young plants which had been developed
from seeds heated to lower temperatures had grown
for thirteen days, their capability of resisting heat
was tested in the manner described, and with this.
result: Those whose roots had been momentarily
exposed to 156° continued to live after they had been
replanted, whilst others whose roots had been exposed
to 167° and upwards speedily dried up and perished,
though all alike had been replanted in carefully
watered earth.

These were the only complete experiments made
by Spallanzani with plants and their seeds; but
many other kinds of seeds only—including those of

HEAT UPON LIVING MATTER. 149
4

the broad-bean, barley, kidney-bean, maize, vetch,

spinach, beetroot, turnip, and mallow—were exposed
to the influence of heat whilst packed in dry sand.
Although this method is less exact and trustworthy,
and is one with which we are not now concerned,
still it may be stated that only four of the numerous
seeds with which experiment was made after this
fashion survived their brief exposure in the dry state
to the temperature of 212°: all the others failed to
germinate.

The Abbé’s researches, therefore, taught him three
things: (1), that eggs can endure a decidedly higher
degree of heat than that proving fatal to animals of
the kind from which they have been derived; (2),
that an analogous difference exists between seeds
and plants in respect to their capacity of withstand-
ing the action of heat; and (3), that seeds and plants
can resist higher grades of heat than eggs and
animals respectively.

After calling attention to these conclusions, Spal-
lanzani said,* “Je suis sans-doute bien dloigné de
prétendre expliquer ces résultats ; je sens la difficulté
de l’entreprise, de sorte que j‘hazarderai tout au plus
quelques conjectures, en les donnant pour ce qu’ elles
valent, et en laissant 4 chacun la liberté de penser
ce quil voudra.” As his conjectures, however, cannot

* Loc. cit., p. 64.

150 THE DESTRUCTIVE INFLUENCE OF

be much improved upon at the present day, it will
be as well to call the reader’s attention to them and
briefly point out their nature.

At the first glance, the Abbé says, the superior
power of resisting heat displayed by eggs and seeds
as compared with animals and plants might be sup-
posed to be due to the developed organisms feeling
the effects of heat more rapidly, owing to their being
free from those envelopes which enclose the egg or
the seed. But the weight of this supposed reason soon
disappears—in the case of eggs, at all events. Look-
ing to the thinness of their investing membrane this
supposition, as Spallanzani says, “ paroit tout-a-fait
peu vraisemblable, quand on pense 4 la facilité et a
la rapidité du feu pour pénétrer une portion de
matiére si mince.” He quickly dismisses—as being
even more improbable—the notion that the smallness
of the germ or egg can act as its safeguard, by
rendering it less amenable to the influence of heat,
Having thus cleared the ground, Spallanzani states
what seems to him to be the principal reason of the
difference observed. We ought to reflect, he says,
upon the difference between the life of an animal in
its egg stage, and its subsequent life as a developed
organism. For however deficient our knowledge may
be upon this subject, we may feel assured that life
shows less of the characters of life in the egg than in

HEAT UPON LIVING MATTER. 151

the organism which is born from it. The life of the
egg is “trés foible’—“sa vie est moins vie.” And
then Spallanzani asks whether the fact of this life of
the embryo within the egg being “so small and so
feeble’”’—being “a life which deserves so little the
name of life”—may not be the reason that eggs are
able to bear the influence of heat better than the
developed organisms whose existence is more active
and complex? He believes this to be the principal
reason of the increased power of resisting heat dis-
played by eggs, and in support of it calls attention
to the fact that many animals (as well as plants), when
the rate of their vital phenomena is lowered, during
winter sleep, are much better able to withstand many
injurious external influences than when they are dis-
playing to the full all the manifestations which
constitute their ‘life. Animals—such as frogs and
salamanders, for instance—resist the effects of injuries
better, when they have been incurred during the be-
numbing cold of winter than at periods of the year
when organisms like these are full of life and activity.

A similar difference obtains between the degree
and complexity of the life of seeds as compared with
that of plants, and this difference may in part simi-
larly explain the superior power of resistance to heat
shown by seeds. Here, also, amongst plants, we find
that ability to withstand hurtful influences generally

152 THE DESTRUCTIVE INFLUENCE OF

increases as their life becomes more sluggish. Thus
Spallanzani says, “ One may say that in winter plants
live less fully than at other seasons, and during this
period they are also much less liable to perish when
they are plucked from the ground or unduly pruned,
than if they had been treated in the same manner
during summer.”

Again, whilst a difference of the same kind may in
part be cited as the cause of the less injurious effect
of heat upon seeds and plants as compared with that
which it exercises over eggs and animals respectively,
Spallanzani believed that the greater tenacitv of life
shown by seeds is only in part due to the fact that the
outer coats of most seeds are much harder than those
of eggs. Thus, the envelopes of some seeds which are
only killed at a temperature near 212° are not harder
than the shell of an egg, which is nevertheless killed
at the much lower temperature of 140° F. This
difference is explicable, according to Spallanzani,
rather by the fact that the fluids contained within the
egg are so much more abundant than those within
the seed. The greater moisture of the animal embryo
causes it more rapidly to experience the full effect of
the heat, so that with a short exposure to a given
temperature the egg may be easily killed whilst the
seed escapes.*

* Spallanzani’s argument thus naturally suggests the notion that many

HEAT UPON LIVING MATTER. 153

Now then for the application of the facts, towards
the interpretation of Spallanzani’s other experiments
in which the lowest organisms appeared in closed
flasks whose contents had been exposed to the tem-
perature of boiling water for half an hour. Certainly
the ‘germs’ of such animalcules could not be supposed
to have survived an ordeal of this kind, if they are to
be compared with the eggs of animals, seeing that the
death of the latter has been brought about by momen-
tary exposure to a temperature far short of the boiling
point. The supposition would however seem more
possible if, instead of comparing these germs with the
eggs of animals, one regarded them as belonging to
the same category as the seeds of plants. Spallanzani
frankly admits that they would seem to be more
allied to eggs than to seeds, though he attempts to
bridge the gap by saying that certain eggs are known
(to which these germs may be allied) in some respects

of the seeds with which he experimented required a high temperature to
kill them, merely on account of their dryness. If the seeds had been
well soaked in cold water beforehand, so as to have thoroughly
moistened them, might they not have been killed at a much lower
temperature—that is, only a little, if at all, above rqgo° F., or the tem-
perature which proved destructive to the more moist animal germs?
Facts to be subsequently mentioned (p 161), which have been ascertained
by Max Schultze and Kiihne, would seem to render this very prubable,
and compel us to regard Spallanzaui’s experiments with sceds as needing
repetition with the modification above suggested. The plants also, like
the animals, should have been wholly instead of partially immersed in
the heated water.

154 THE DESTRUCTIVE INFLUENCE OF

resembling seeds. Such eggs,—‘become dry, are
preserved in this state, and then develop like seeds
after they have been placed in some damp medium.”
“Why then,” he adds,* “may not the germs of the
lowest kind of animalcules be possessed of a similar
nature?” He next adduced various considerations
which led him to regard this view as more and more
probable, though none of his reasons would be deemed
very weighty or even relevant by physiologists of the
present day. The space at my disposal will not
permit of my following him into these discussions—
the reader curious on the subject can, however, con-
sult Spallanzani’s work for himself.

In respect therefore to the questions with which
we are now more especially concerned, the contro-
versy carried on between Spallanzani and Needham
about a century ago led to the following important
results. Not a single living thing, egg, or seed, had
been shown to be able to resist, when in the moist
state, an exposure to boiling water for a single
moment. AllI naturally moist forms of living matter
with which experiment had’ been made, had been
shown to be killed by a much lower heat—that is, at
a temperature of about 140° F. or less.

And in order to account for the appearance of the
lowest animalcules in previously boiled fluids, other-

* Loc. cit., pp. 69—73.

HEAT UPON LIVING MATTER. 155

wise than by ‘spontaneous generation,’ Spallanzani
was compelled to assume (2) that the unknown germs
whose existence had been postulated, notwithstanding
their animal origin, were of the nature of seeds rather
than eggs, because they were capable of undergoing
desiccation with impunity—such ability to survive
desiccation conferring upon them the greater power
of resisting heat which characterizes seeds. Nay,
further (4), although no seeds could be shown to be
able to resist the influence of boiling water, Spallan-
zani assumed that these unknown seed-like germs
might be able to do so.* Thus alone was he able to
continue in the Panspermatist faith—on the strength ,
of these hazardous assumptions only, could he refuse
assent to the probability of a germless origin of living
matter, more or less after the fashion suggested by
Needham and others.

We may, therefore, now consider how far «the pro-
gress of science has tended to confirm or reverse the
hypothesis by which Spallanzani sought to shelter

* He had only met with a few seeds which had resisted a momentary
exposure in dry sand to a temperature of 212° F. But seeing that not
one of the numerous seeds with which he had experimented had been
able to survive a similar momentary exposure to boiling water, he had
no real warrant for supposing that the germs in question would be able
todoso. Spallanzani, in short, here committed the error of arguing that
what had occurred in dry sand might occur in water—even though
his own experience had not supplied him with a single instance of
survival of egg or seed after it had been even momentarily scathed by

boiling water.

156 THE DESTRUCTIVE INFLUENCE OF

himself, and ward off the conclusions of his opponent.
He saw fully, and had frankly admitted,* that there
was but one means of escaping from Needham’s con-
clusions. But, were these means legitimate?

(a2) Although it is doubtless true that the superior
dryness of seeds does enable them to resist the in-
fluence of heat longer than moist eggs are able to do,
and therefore also enables them apparently to resist
for a brief period a temperature notably higher than
would have proved fatal to them had they been ina
moist state—it is altogether another question when we
have to decide whether the naturally moist Bacteria
or their germs are really endowed with this seed-like
property of developing after desiccation. To main-
tain his Panspermism in the face of his own experi-
ments, Spallanzani was compelled to assume that
the germs of the lower Infusoria do possess this
potentiality. Modern science, however, declares.that
they have no such property. We are told most un-
reservedly by Professor Burdon Sanderson,t not only
that “the germinal particles of microzymes [Bacteria]
are rendered inactive by thorough drying without
the application of heat,” that is, by mere exposure
to air for two or three days at a temperature of

* See p. 142.
+ ‘Thirteenth Report of the Medical Officer of the Privy Council,”
p. 61.

HEAT UPON LIVING MATTER. 157

104° F., but also that, ‘‘fully-formed Bacteria are
deprived of their power of further development by
thorough desiccation.” Thus is the most important
assumption made by Spallanzani swept away, and
with it all the strength that his position may
have appearéd to possess. His followers cannot
hope to save their germs from the full action of
heat, however much they may wish to do so (and
there are strong signs that they are thus influenced)
by assuming the pre-existence of a protective desic-
cation. Are they not told, on what is to them the
unquestionable authority of Professor Sanderson, that
such desiccation would be in itself destructive ?

(6) We are left, therefore, face to face with only
one other question. Has the progress of science, it
may be asked, since the time of Spallanzani, in any
way tended to strengthen the possibility that Bacteria
germs, or any forms of living matter in the moist
state, can resist the destructive action of boiling water,
even for two or three minutes? To this question a
negative answer may be unreservedly given. The pro-
gress of science has, on the contrary, shown that such a
supposition becomes more and more improbable when
judged by the light of all uncomplicated investigations
bearing on the subject. To these results of modern
research I must now call the reader’s attention.

In the first place the specific question with which

158: THE DESTRUCTIVE INFLUENCE OF

we are more immediately concerned, as to the thermal
death-point of Bacteria and their germs, has itself
been answered by most decisive experiments. As
the writer has elsewhere already shown,* all direct
experimentation on this subject leads to the conclusion
that Bacteria and their germs, whether visible or in-
visible, are killed by a brief exposure to a heat of
140° F. in the moist state. Thus Dr. Sanderson’s
experiments having proved that the germs of these
organisms are, as regards their ability to withstand
desiccation, related to eggs rather than to seeds,
the writer's own experiments tend still further to
strengthen this resemblance by showing that these
Bacteria germs (like the eggs with which Spallanzani
experimented) are invariably killed at a temperature
of about 140° F.

Although, therefore, my experiments are not
favourable to Spallanzani’s assumptions, they are
entirely in accordance with his experiments. The
thermal death-point ascertained by him for the eggs
of Insects and of Batrachia agrees almost exactly
with that which I have established for Bacteria
germs—although at the time my own experiments
were made I was unaware of these particular results .
obtained by Spallanzani.t

* In the two papers which precede this.
+ Up to that time I had read his earlier work entitled, “ Nouvelles

HEAT UPON LIVING MATTER. 159

Is there, then, anything in this fact concerning
Bacteria and their germs at all at variance with
what we might have been led to expect, judging
from our knowledge of the capacity for resisting heat
shown by other kinds of living matter? Here again
a negative answer may be unreservedly given. The
grounds for this opinion must, however, be set forth ;
and in dealing with this important question I will-
range what I have to say under the following
heads :—(1) The results obtained by many other
investigators working quite independently of one
another (and in many cases also without distinct
reference to the Origin of Life question) all go
to show that different kinds of living matter are
killed, when heated in the moist state, at or below
the temperature of 140° F. (2) The only known
exceptions to this rule, furnished by organisms in hot
springs, are cases of a special kind differing altogether
from those with which we are at present concerned :
though even here it is found that all such organisms
perish at temperatures short of the boiling point.
(3) Our knowledge as to the thermal death-point of
Living Organisms and of units of Living Matter is
remarkably harmonious, and is in accordance there-

Recherches sur les Découvertes Microscopiques, et la Génération des
Corps Organisés,” &c., and not the one from which I have just been

quoting.

160 THE DESTRUCTIVE INFLUENCE OF

fore with what we know concerning the unity of
living matter generally. (4) The assumptions en-
tertained by some modern Panspermatists in sup-
port of their notion that living matter unaccus-
tomed to the influence of heat is able to resist
the destructive action of boiling water, are of the
most frivolous nature-—alike unsupported by ex-
periment and contradicted by all ordinary expe-
rience. .

(1.) Liebig proved that sugar-yeast (Torula cere-
visi@) entirely lost its power of growth and germi-
nation at 140° F.* It was ascertained by Tarnowski,
after numerous experiments conducted, as Sachs
says,t “with all possible precautions,” that spores
of Penicillium and other common fungi, also. most
closely related by nature to Bacteria, “entirely lost
their power of germinating when heated in their
own nourishing fluids” to a temperature of 131° F.
Again, it has been ascertained by Dr. Timothy

* M. Pasteur’s very important mode of effecting the preservation of
wines is based upon a similar fact. He says (Compt. Rend. t. Ixxv.
1872, p. 304) :—‘‘ Toutes les maladies habituelles des vins sont dues
4 des champignons microscopiques.” Raising the wines in bottle to a
temperature of about 60° C. (140° F.) suffices, he adds, to kill these
fungi and their germs. In short an experience of six or seven years has
shown that ‘‘aprés une exposition rapide 4 une température comprise
entre 55 et 65 dégrés” the wines no longer become sick, but even im-
prove in quality.

+ “Lehrbuch der Botanik,” 3rd ed., p. 626.

HEAT UPON LIVING MATTER. 161

Lewis* that the germs of tape-worms are invariably
killed at the temperature of 140°, whilst Professor
Mantcgazza. has shown that the male reproductive
particles of frogs are killed by exposure to-a heat
of 131° So far, therefore, concerning germs, in
addition to what I have already mentioned about
Spallanzani’s observations upon the eggs of Insects
and Batrachia.

Turning our attention next to adult organisms of
different kinds or to their elemental parts, the
following facts may be cited. Pouchett found that
all kinds of Ciliated Infusoria were certainly killed
at 131° F., and whilst confirming this observation
the writer found that a brief exposure to the same
temperature always sufficed to kill Amoebe, Monads,
Euglenez, Desmids, Rotifers, Nematoids, and other
minute aquatic organisms. The writer did not try
to ascertain what was the lowest temperature which
would prove fatal to these organisms, though ' this
has been done by other observers. Spallanzani, for
instance, ascertained that Ciliated Infusoria, Water-
fleas, Leeches, Nematoids, and other worm-like
creatures, all perished at 107-113° F.; whilst Max

* “Fighth Annual Report of the Sanitary Commissioners with the

Government of India,” 1871, p. 139. Prof. Pellizzari has also of late
acrived at similar results (see ‘‘The London Medical Record,” Oct.

14, 1874, p. 641).
+ “Nouvelles Expériences,” &c., 1864, p. 33.

162 THE DESTRUCTIVE INFLUENCE OF

Schultze * and Kiihnet (in part working over the
same ground) have quite recently fixed the heat
limits fatal to such organisms at temperatures
varying between 104° and 113° F. At these tem-
peratures, indeed, the protoplasm entering into their
formation, as well as that of the tissue elements of
higher animals, was not only killed, it became
coagulated and assumed the condition named by
Kiihne ‘heat-stiffening.”” Both Max Schultze and
Kiihne also found that the protoplasm of plant-cells
with which they experimented (belonging to the
genera Urtica, Tradescantia, and Vallisneria) was
similarly killed and altered by a very brief ex-
posure to a temperature of 1183° F. as a maximum.
-All accurate new observations, therefore, go to prove
that different kinds of living matter, whether in the
form of germ or of developed organism, are killed
by a brief unaccustomed exposure in the moist
state to a temperature at or below 140° F.

(2.) So far I have been referring to the influence
of heat upon living matter when it is suddenly
applied to an altogether unaccustomed extent. This
is the mode of operation with which we are especially
concerned, as with the view to the interpretation of

* “Das Protoplasma,” Leipzig, 1863, pp. 33 and 46.
+ “Untersuch ueber das Protoplasma und die Contractilitat,”
Leipzig, 1864, pp. 46 and 103.

HEAT UPON LIVING MATTER. 163

experiments on the Origin of Life question we wish
to know the effects of great heat upon organisms
accustomed to ordinary atmospheric and aquatic
temperatures. On the other hand, it should be
pointed out that organisms have been found living
in hot springs at temperatures very considerably
above those I have just been quoting ; although the
very highest of the temperatures, under the influence
of which living things have been reported as existing
in thermal springs, is still a few degrees below the
boiling point of water. The various observations
made upon this subject have been collected and
criticised with much care by Professor Jeffries
Wyman,* to whose paper I would refer the reader.
The most remarkable instances—that is, the highest
temperatures cited which are at all trustworthy—in
which Conferve, or allied organisms, have been met
with, are thus summarized by Professor. Wyman.
“The statements we have quoted,” he says, “ give
satisfactory proof that different kinds of plants may
live in water of various temperatures, as high as
168° F. as observed by Dr. Hooker in Sorujkund ;
174° as observed by Captain Strachey in Thibet ;
185° as observed by Humboldt in La Trinchéra ;
199°:as. observed by Dr. Brewer in California; and
208° as observed by Descloizeaux in Iceland.”
* ¢¢ American Journal of Science and Arts,” vol. xliv., Sep. 1867.
M 2

164 THE DESTRUCTIVE INFLUENCE OF

Having no grounds for criticising these observations,
we are bound to look upon them, provisionally at
least, as correct and taken with all due care—though
it is only fair to add that both Max Schultze and
Cohn appear to be not altogether satisfied with
some statements of the same kind,* Such instances,
if thoroughly accurate, may perhaps be taken as
examples of the- highest temperature that it is
possible for living matter to endure, even where it
has been inured to the influence of heat in the
most gradual manner. And the real point of view
from which such facts should be regarded is pointed
out by Professor Wyman when he says: “ Having
become adapted through a long series of years to
their surroundings, such organisms may be supposed
to live under circumstances the most favourable
possible for sustaining life at a high temperature.
It is a well-known physiological fact, that living
beings may be slowly transferred to new and
widely different conditions without injury; but if
the same change is suddenly made they perish. In
the experiments made in our laboratories, the
change of conditions is relatively violent, and there-
fore liable to destroy life by its suddenness,” ‘Hence
it is that a considerably lower temperature than that
of the springs above mentioned suffices to kill all

* See Max Schultze, “Das Protoplasma,” Leipzig, 1863, p. 67.

HEAT UPON LIVING MATTER. 165

living matter not previously inured to the influence
of heat.

(3.) Omitting, therefore, the facts concerning the
existence of living organisms in thermal springs as
being altogether peculiar, and lying outside the
boundaries of our present inquiry, all that we know
about the unaccustomed influence of high tempera-
tures upon living things can easily be shown to be
even more harmonious than it may at the first
glance appear. We have only to bear in mind two
or three general principles in order to be able to
harmonise the several experimental results arrived
at with the now very generally admitted doctrine
as to the oneness or generic resemblance existing
between all forms of living matter. We must bear
in mind, first of all, the consideration enforced by
Spallanzani, that there are different grades of
vitality, or, in other words, different kinds of living
matter exhibiting more or less of the phenomena
known as vital; and that of these kinds those which
exhibit the most active, life are those which would
be most easily killed by heat. Thus we should
expect the latent ‘life’ of the germ, egg, or seed
to be less easily extinguished than the more subtle
and, at the same time, more active life of the fully
developed tissue element or organism; and we should
also expect that the vegetal element or organism

166 THE DESTRUCTIVE INFLUENCE OF

would, as a rule, be less readily killed than the
more highly vitalised animal element or organism.
These principles, based upon the consideration of
relative complexity of life, are, however, subject to
the influence of a disturbing cause. Thus, we must
also take into account, in the case of animals,
whether we have to do with the elements of a
warm-blooded or of a cold-blooded organism, since,
contrary to what might otherwise have been the
case, custom or habitual conditions may tend to
render the more active tissue elements of warm-
blooded animals better able to withstand the
influence of heat than similar elements of less
highly vitalised cold-blooded animals, Keeping
these considerations in view, therefore, we may see
by the following figures, how harmonious are the
facts already ascertained !

Temperatures at which Death occurs.

are killed at
Simple aquatic organisms ‘ 104°-113° F,
(Spallanzani, Max Schultze and .
Kiihne.)
Tissue elements of cold-blooded
animal—Frog , ‘ ‘ : 104
(Kiuhne.)

HEAT UPON LIVING MATTER. “467

are killed at
Tissue elements of warm-blooded

animal—Man : j : I1I°
(Stricker and K ithne)
Tissue elements of Plants—Urtica,
Tradescantia and Vallisneria . 116$°-1184°
(Max Schultze and Kiihne.)
Eggs, F pees alae! and Bacteria

germs. : : . 122°-140""
(Spallanzani, Liebig, 7. dsssb
and others.)

So far as can be ascertained by really scientific
methods, free from all obvious possibilities of mis-
representation, these are the temperatures which
undoubtedly kill the different varieties of that
common life-stuff known as Protoplasm — the
“physical basis of life,” as it has been termed by
Professor Huxley. That it should present this
comparative unity in its behaviour towards heat as
weil as to other physical agencies, is surely not in
antagonism with the generally-approved biological
doctrines, of which Professor Huxley has made
himself the most celebrated exponent in this country,
In his own forcible language he tells us as follows :*
—“ Beast and fowl, reptile and fish, mollusc, worm,

* “Lay Sermons,” pp. 126-129.

168 THE DESTRUCTIVE INFLUENCE OF

and polype, are all composed of structural units of
the same character, namely, masses of protoplasm
with a nucleus . . . . What has been said of the
animal world is no less true of plants. . . . Proto-
plasm simple or nucleated is the formal basis of all
life. . . . Thus it becomes clear that all living
powers are cognate, and all living forms are funda-
mentally of one character.”

‘Before the breath of controversy had arisen Pro-
fessor Huxley was, moreover, inclined to believe that
this protoplasm or primitive life-stuff would display a
comparatively uniform behaviour under the influence
of heat. Thus in the essay from which I have just
quoted, he says, it cannot “be affirmed with perfect
confidence that all forms of protoplasm are liable to
undergo that peculiar coagulation at a temperature
of 40°—50° Centigrade which has been called ‘heat-
stiffening, though Kihne’s beautiful researches have
proved this occurrence to take place in so many and
such diverse living beings, that it is hardly rash to
expect that the law holds good for all.”

(4.) I now turn to say a very few words concerning
the general attitude and specific statements made by
those who, still wishing not to give in their adherence
to the fact of the occurrence of ‘spontaneous gene-
ration,’ affect to believe that Bacteria germs or other

HEAT UPON LIVING MATTER. 169

kinds of living matter can resist the influence of
boiling water.

In the first place it should be said that not one
of these modern Panspermatists has striven to justify
his position by scientific evidence bearing directly
upon the death-point of Bacteria and their germs,
whilst several of them have openly attempted to
make good their position in the most unscientific
manner — that is, by adducing, when facts seem
adverse, experiments admitting of two interpretations,
as though they only admitted of one, and then of
these two possible interpretations selecting that which
the experiments were neither calculated to warrant
nor originally destined to illustrate. This shuffling
with conclusions becomes all the more reprehensible
when the interpretation selected is known to be
directly contradicted by other less equivocal evidence,
as to the very existence of which, however, those who
adopt this course take care to say nothing.* This
is a kind of treason to Science, of which one can
only hope that the future may prove less prolific
than the past has been.

And, if we turn now to the specific statements
made by those who profess to believe that Bacteria
and their germs are able to resist the influence of

* See p. 136, Also ‘‘ Nature,” 1873, Nos. 190-193, 206, 207, and
209,

170 THE DESTRUCTIVE INFLUENCE OF

boiling water—we discover in the first place that all
who advance such suppositions find it cenvenient to
pass unnoticed the several series of experiments by
which it has been proved, that Bacteria and their
germs are uniformly killed by an exposure to 140° F.
for five minutes. My opponents find it most con-
venient to take no notice of these experiments,
though no one has as yet attempted to dispute their
cogency. They prefer to talk vaguely, as though
such experiments had never been made, and to
adduce various theoretical reasons whose validity
they do not attempt to test experimentally. To do
this, indeed—as they must be more than half aware
—would be a vain attempt, since the suppositions
which they advance are opposed to generally-
accredited facts and scientific doctrines, even if they
have not already been specifically refuted.

The suppositions principally dwelt upon may be
ranged under three categories.

(a.) It is assumed by some that the mere minute-
ness of the germs of Bacteria may serve to protect
them from that destructive influence which heat
exercises upon living matter generally.* This is

* Some of those who rely upon this supposed reason have resorted
to direct attempts to ascertain the death-point of the germs of other
organisms, although their results have been, in part, vitiated by the

evaporation of the drop of fluid employed—so that the organisms were
subsequently exposed to the higher degrees of heat in a dry state.

HEAT UPON LIVING MATTER. I7I

an old objection entirely unsupported by facts, and
those who dwell upon it may be reminded that it was
unhesitatingly rejected by the former chief of their
school, Spallanzani, who said, “un raisonnement de
cette sorte est absoluement contraire a toutes les
notions que nous avons du feu.” They may be
further reminded that the writer’s own experiments
completely meet this objection, since they. refer to
the death-point of invisible germs of Bacteria just
‘as much as to the death-point. of those which are
visible.*

(6.) Others, without definitely committing them-
selves to the belief that Bacteria germs can resist
the destructive influence of boiling water when they
are immersed in it, affect to believe that some germs
may have escaped its influence by being -‘sourted’
out of the fluid on to the sides of the glass when the
process of boiling commenced. How any such germs
could escape the moistening and destructive influence
of the hot steam with which they would still be in
contact these reasoners do not say, though some of
them are cautious about openly suggesting an ante-
cedent and protective state of extreme desiccation
in the face of Dr. Sanderson’s experiments proving
that this would be in itself destructive. The futility
of this objection, so far as the general question is

* Seep. 86.

172 THE DESTRUCTIVE INFLUENCE OF

concerned, has, moreover, been completely demon-
strated by the fact that organisms will occur just as
freely under conditions where no such objection can
be alleged, that is, when the vessel and its contents
are heated by submergence in boiling water, after
it has been hermetically sealed—a mode of heating
which those who adduced the objection above men-
tioned ought to have known had been occasionally
adopted by different experimenters since the time
of Spallanzani.

(c.) The third objection raised is no less remark-
able, owing to its being similarly brought forward
as an unsupported supposition in the face of much
other evidence testifying to its nullity. When the
writer's earlier experiments were first recorded, the
public was authoritatively told by ‘Professor Huxley
that the results were quite unworthy of credence.
The fact that tons of meats and vegetables were an-
nually preserved from putrefaction by a very similar
process was supposed to be the strongest evidence
that he had in some manner deceived himself. It
was never suggested or thought of, therefore, at this
time that such moist meats and vegetables were in-
capable of being heated through, even when pounds
of them were aggregated together. It was, in short,
implicitly said that they could be so heated, and the
fact of the preservation of the meats and vegetables

HEAT UPON LIVING MATTER. 173

was itself deemed to be the best evidence that all
‘germs’ which might have been contained in their
interior had been killed. Now that the writer has
demonstrated to unbelievers, and when others have
ascertained for themselves, that organisms are to be
met with and that putrefaction will occur within
almost airless and hermetically sealed flasks whose
contents have been previously boiled, the tactics of
these unbelievers are entirely changed. Forgetting
altogether the previous objection upon which they
telied so long as they doubted the writer’s facts, they
now advance an interpretation of his results, which.
must carry with it its own stultification to the minds
of those who are not similarly oblivious of their
previous position. The writer’s methods are declared
to be faulty because he did not think it needful to
free his infusions from all particles, however minute
and however soft. Impetuous critics now shake their
heads, and talk with apparent learning about “the
protective influence of lumps.” Whilst heat was
previously supposed to be capable of operating asa
germ-killer through pots of meats and vegetables,
and whilst it has been proved to act in the same way
through the thick and dry envelopes of seeds, now
a pea or a minute particle of cheese, even though
smaller than a pin’s head, is thought to exercise a
“ protective influence” over imaginary germs!

174 THE DESTRUCTIVE INFLUENCE OF

Such puerilities might safely be left to die a natural
death, though it may be as well to remind those who
profess to trust to them, that although they do not
put their notions to the test of direct experiment,
others have, for certain practical reasons, had occasion
to do so. Dr. Timothy Lewis, who has been for some
time in Calcutta carrying on, in concert with Dr, D.
Cunningham, important sanitary investigations, has,
amongst other things, directed his attention to the
vitality of tape-worm germs in cooked meat. He
proved, first, that tape-worm germs are undoubtedly
killed by exposure for five minutes to a tempera-
ture of 140° F.; and then, with the view of ascer-
taining how far they would be likely to experience
such a temperature in the ordinary process of meat-
cooking, he made other important observations hav-
ing considerable interest for us. Dr. Lewis found
that when legs of mutton had been put into the
boiler almost as soon as the water, their central
temperature averaged 140° F. by the time the water
around them had reached the boiling point ; and that
after the water had boiled for five minutes, the in-
ternal temperature of other legs of mutton which had
remained in the boiler had on an average reached 170°.
This is a practical method of dealing with the question
which those sceptical dreamers who talk of the “protec-
tive influence of lumps” would do well to imitate.

HEAT UPON LIVING MATTER. 175

After this I may perhaps be deemed fully justified
in quoting two very typical experiments for the
further consideration of those who stave off their
belief in the occurrence of ‘spontaneous generation
—either by relying upon insufficient reasons for
doubting the influence of boiling water, or because
of their following Pasteur, Cohn, and others, in
supposing that certain peculiar Bacteria germs are
not killed except by a brief exposure to a heat of
227° or 230° F. For even if we could grant them
these limits, of what avail would the concession be
towards averting the dreaded admission of the oc-
currence of ‘spontaneous generation,’ in the face of
the following experiments, and others of a similar
nature ?.

Experiment I.—A strong infusion of turnip was
rendered faintly alkaline by liquor potasse, and to
this a few separate muscular fibres of a cod-fish were
added. Some of this mixture was introduced into a
flask of nearly two ounces capacity. Its neck was
drawn out and afterwards hermetically sealed by
the blow-pipe flame, whilst the fluid within was
boiling. When thus closed the flask was about half
full of fluid. It was then introduced into a digester
which was gradually heated, and afterwards kept at
a temperature of 270-275° F,, for twenty minutes,
though it seems also well to point out that if we

176 THE DESTRUCTIVE INFLUENCE OF

include the time taken for the water of the digester
(in which the closed flask was immersed) to attain
this heat, and also again to cool down to 230° F.,
this flask was exposed to temperatures above 230° F.
for ONE HOUR, as I myself .carefully noted at the
time. When withdrawn from the digester the closed
flask was kept at a temperature of 70-80° F. for
eight weeks, and during part of this time it was
exposed to the influence of direct sunlight. After
it had been ascertained that the flask was free from
all crack or fault, its neck was broken, in order that
its contents might be examined. The reaction of the
fluid was found to have become decidedly acid, and
it had a sour though not fcetid odour, as though a
fermentative process had been taking place in the
solution. The fluid was very slightly turbid, and there
was a well-marked sediment consisting of reddish-
brown fragments, and of a light flocculent deposit.
On microscopical examination the fragments were
found to be portions of altered muscular fibre, whilst
the flocculent deposit was composed for the most
part of granular aggregations of Bacteria. In the
portions of fluid and of deposit which were examined,
there were thousands of Bacteria of most diverse
shapes and sizes, either separate or aggregated into
flakes. There were also a large number of monilated
chains, of various lengths, of a kind very frequently

HEAT UPON LIVING MATTER. 7

met with in abscesses and other situations, where
pyemia or low typhoid states of the system exist,
in the human subject. There were, in addition, a
large number of ZYorula corpuscles, as well as of
brownish nucleated spore-like bodies, gradually in-
“credsing in size from mere specks, about zy3qqth up
to gs/yath of an inch in diameter. Lastly, there was
‘a small quantity of a mycelial Fungus filament,
bearing short lateral branches, most of which were
capped by a single spore-like body. (See Fig. 1.)
Experiment IT. A strong infusion of common cress
(Lepidium sativum), to which a few of the leaves and
stalks of the plant were added, was inclosed in an
hermetically-sealed flask in the same way, heated in
the digester at the same time (and therefore to the
same temperature), and was subsequently exposed to
the influence of the same conditions as I have already
mentioned in connection with the last experiment.
This flask was, however, opened one week later—that
is at the close of the ninth week after it had been
heated in the digester to 270-275° F. Before break-
ing the neck of the flask the inbending of the glass
under the blowpipe flame showed that it was still
hermetically sealed. The reaction of the fluid was
found to be distinctly acid, though there was no
notable odour. The fluid itself was tolerably clear
and free from scum, but there was a dirty-looking
N

178 THE DESTRUCTIVE INFLUENCE OF

flocculent sediment at the bottom of the flask,
amongst the éébris of the cress. On microscopical
examination (with a 7,th “immersion” objective)
much altered chlorophyll existed, either dispersed
or aggregated amongst the other granular matter
of the sediment, and amongst some of this three
minute and delicate Protamebe were seen, varying
in form, and creeping with moderately rapid slug-
like movements. They contained no nucleus, and
presented only a few granules in their interior. In
the same drop of fluid, and also in others subse-
quently examined, more than a dozen very active
Monads (goth of an inch in diameter) were seen,
each provided with a long, rapidly-moving lash by
which neighbouring granules were freely knocked
about. There were many smaller motionless and:
tailless spherules of different sizes, whose body:
substance presented a similar appearance to that of
the Monads—and of which they were, in all proba-
bility, earlier developmental forms. There were also
several unjointed Bacteria, presenting most rapid
progressive movements accompanied by quick axial
rotations. Many Yoru/a corpuscles and other Fun-
gus “spores” also existed, as well as portions of
a mycelial filament containing equal segments of
colourless protoplasm within its thin investing mem-
brane. (See Fig. 2.)

HEAT UPON LIVING MATTER. 179

A drop of the fluid containing several of these
active Monads was placed for about five minutes on
a glass-slip in a water oven maintained at a tem-
perature of 140° F. All the movements of the
Monads ceased from this time, and they never after-
wards showed any signs of life.

These experiments are merely two of the most
remarkable selected from several others in which
even higher temperatures were originally had re-
course to in order to free the fluids and flasks
generally from anything like a trace of living matter.
Nothing that has yet been alleged by way of objec-
tion to the admission of ‘spontaneous generation’ as
an everyday fact, at all affects such experiments as
these. The shortest way out of the difficulty would
therefore be to doubt the facts. I can assure the
reader, however, that they are as true and quite as
reliable as those other results obtained when work-
ing with lower temperatures, which, though strongly
disbelieved in at first, are now generally recognized.
as trustworthy. And although ‘these now accredited
results abundantly suffice, in face of our present
knowledge concerning the limits of vital resistance
to heat, to establish the strongest probability of the
occurrence of ‘spontaneous generation,’ yet such ex-
periments as those which I have now recorded even
still further confirm this view, since .it becomes in-

: N 2

180 THE DESTRUCTIVE INFLUENCE OF

credible that whilst all known forms of living matter
with which accurate experiment has been made in-
variably perish at or below 140° F., the particular
examples of some of the same forms which appear
within our sealed flasks have been able to survive a
much longer exposure to 270-275° F. If this were
true, then indeed would the cultivation of Science be
a vain pursuit— uniformity,’ in fact, must be postu-
lated and granted, or Science with humbled and
sorrowful crest must retire from the field.

A word or two may be said in conclusion with
reference to the interpretation which should be at-
tached to such experiments as those just recorded.
And this subject cannot be better introduced than
by means of the following extract from the already-
quoted and valuable paper by Professor Jeffries
Wyman.* He says :—“ There can therefore be no
certainty of the existence of spontaneous generation
in a given solution, until it can be shown that this
has been freed of all living organisms which it con-
tained at the beginning of the experiment and kept
free of all such from without during the progress
of it. On the other hand, this kind of generation

* Whilst these pages have been passing through the press the sad
news has reached us of the premature death of Professor Wyman. In
him Science has lost one of her most faithful followers.

HEAT UPON LIVING MAT. TER. 181

becomes probable, whenever it is made certain that
Infusoria are generated in solutions in which the
conditions just mentioned have been complied with.
We say probable, because their appearance under
such circumstances would not amount to a proof.
The absolute proof of spontaneous generation must
come from the formation of living organisms out of
inorganic matter. If Infusoria are generated in
solutions of organic matter, independently of spores
or germs, the question may be fairly raised whether
we do not begin the experiment with materials in
which life already exists, even though this material
is not in the form of distinct organisms.” Now,
these last few lines as they at present stand, tend,
as it appears to me, to convey to the reader very
erroneous impressions—and yet I am aware that
views of the same kind are very commonly ex-
pressed, and seem to exist in an inchoate or half-
realised form in the minds of many distinguished
‘persons. It is for this reason, and on account of
the authority attaching to Professor Wyman’s state-
ments that I am induced to take notice of this
particular passage in order to attempt its recti-
fication.

In the first place then, under the old term,
‘spontaneous generation’ are included two processes
quite distinct from one another—namely, Hetero-

182 THE DESTRUCTIVE INFLUENCE OF

genesis and Archebiosis. With regard to Hetero-
genesis, this is merely the opposite of Homogenesis ;
and the latter is the name for that mode of gene-
ration or reproduction amongst living things which
is looked upon with most respect and which is most
generally known. It is the process by which “like
produces like ”—that is, where the offspring grow into
beings similar to their parents. In Heterogenesis,
on the other hand, we have the birth of dissimilar
products, the beginning of a new branch from a
“‘life-tree,” in which the offspring have no tendency
to assume the parental type. This occurs, for
instance, where the protoplasmic matter of an animal
or of a vegetal cell becomes modified and resolved
into Bacteria. Here we have to do with the mere
transformation of living matter. It is therefore a
truism to say that it can only take place where
living matter pre-exists. And seeing that many
investigators, amongst whom I may especially
mention, Needham,* Pouchet, and Trécul, have, both
now and formerly, understood by the phrase ‘ spon-
taneous generation, merely such a process of meta-
morphosis of living matter as is implied by the
term Heterogenesis, it is, to say the least, very mis-
leading to assert without qualification that, “the
absolute proof of spontaneous generation must come

* See ‘‘ The Beginnings of Life,” vol. i., pp. 246-252, and vol. ii., p. 181.

ITEAT UPON LIVING MATTER. 183

from the formation of living organisms out of in-
organic matter.”

It seems obvious, however, that when Professor
Wyman wrote this passage, he, forgetting for the
time the more common acceptation of the phrase
‘spontaneous generation, must have used it only in
the sense in which I now employ the term Arche-
biosis—in the sense, that is, of life-origination. But,
even taking the phrase ‘spontaneous generation’ in
this one sense only, how far, we may ask, was
Professor Wyman justified in saying that its
proof “must come from the formation of living
organisms out of inorganic matter?”

The statement is, in my opinion, one which cannot
be logically entertained by a believer in the ordinary
physical doctrines of life; and consequently, if Iam
correct in this view, it should be professed by no
consistent believer in Evolution. Those who do not
assent to these physical doctrines of life would
probably never be able to believe in Archebiosis at
all—to the ‘vitalist, life is an immaterial principle
specially created, and therefore our flask experiments
terminating in the birth of new organisms, could at the
most be regarded by him as proving the occurrence of
Heterogenesis. Life was there, he might say, as an
indestructible principle, so that the new organisms
avhich appear are simply new embodiments of this

184 THE DESTRUCTIVE INFLUENCE OF

‘principle’—a kind of transformation has taken place.
This, in short, is the view to which a vitalist would
be driven, if he had become convinced that no germs
of Bacteria, or of such other organisms as are found
in our flasks, could have survived the preliminary
process of heating. Such a vague sort of position
is not open, however, to evolutionists or to those
who believe in the now generally accepted physical
doctrines of life. They are bound to recognize the
undoubted distinction which exists between mere
dead organic matter, and that organic matter which
displays the phenomena of life. They should no
more think of calling a body ‘living’ which could
not be made to display the characteristics of life,
than they would call a body ‘magnetic, when it
would show none of the properties pertaining to
magnetism. If they had learned, therefore, that
living matter when exposed to heat of a certain
intensity became lifeless matter (that is, that it
could no longer be made to display the phenomena
of life), the process by which new living protoplasm
comes into existence amongst this dead organic
material, would be, for them, as much an instance
of its new independent origin as if the process had
occurred in the midst of mere inorganic elements,
The term Archebiosis is therefore applicable to the
process that must take place in our ordinary flask

HEAT UPON LIVING MATTER, 185

experiments where we deal with dead organic matter,
just as it is also applicable to those more primordial
combinations which first gave birth to living proto-
plasm on the surface of our Earth.

Should there be persons still reluctant to accept
this conclusion, simply because they cannot bring
themselves to believe in a process of ‘ origin,’
concerning the actual steps of which they know
nothing, one may ask whether it ever occurred to
them to doubt the fact of the increase in size of
an elm-tree simply because they were similarly
unable to know the intimate nature of those nutritive
processes, by which dead inorganic elements are
fashioned into its living substance—because in short
they do not know the secret steps of the process
by which its ‘growth’ is accomplished !

And in reply to those who speak scornfully,
because of the complexity of some of the organic
mixtures which have been employed, I would say
that. my object throughout has been to establish,
in the first place, the mere fact of the occurrence of
Archebiosis. And whilst thinking that this could
be done most easily, if at all, by making use of
organic mixtures, I also felt sure (for the reasons
already stated) that it could be dane just as decisively
with them as with simpler solutions of more definite

composition.

186 JMFLUENCE OF HEAT UPON LIVING MATTER.

Having established the fact of the present ele-
mental ‘origin’ of living matter, those who choose
may afterwards seek to discover and explain the
“steps by which it occurs. This appears to me to
be at present an almost hopeless line of research.
And certainly before venturing to attempt to
unravel a problem so exceedingly difficult and
complex, I should strive to solve the riddle of
organic ‘growth.’ What, for instance, are the steps
of the process by which protoplasm is produced
from the elements of a simple solution of ammonic
tartrate, when Bacteria are rapidly growing and
multiplying therein? Here is the problem of
growth and nutrition in its simplest form! Yet
who can solve it? Till this is done we shall
stand little chance of discovering the chemical stages
of the process by which Living Matter originates.

Meanwhile let none forget, that, from the point
of view of our ignorance of the intimate nature
of both processes, we may as reasonably doubt the
fact that Living Matter grows as we may doubt
the fact that it can arise independently — and,
further, let none forget that Origin and Growth are 7
in essence merely stages of one and the same
process.

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