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LIVERPC ‘0OL, 1896,

ADDRESS

BY

SIR JOSEPH LISTER, Barr., D.C.L., LL.D., P.R.S.,

PRESIDENT.

My Lord Mayor, my Lords, Ladies, and Gentlemen, I have first to
express my deep sense of gratitude for the great honour conferred upon
me by my election to the high office which I occupy to-day. It came
upon me as a great surprise. The engrossing claims of surgery have
prevented me for many years from attending the meetings of the
Association, which excludes from her sections medicine in all its
branches. This severance of the art of healing from the work of the
Association was right and indeed inevitable. Not that medicine has
little in common with science. The surgeon never performs an operation
without the aid of anatomy and physiology; and in what is often the
most difficult part of his duty, the selection of the right course to follow,
he, like the physician, is guided by pathology, the science of the nature
of disease, which, though very difficult from the complexity of its subject
matter, has made during the last half-century astonishing progress ; so
that the practice of medicine in every department is becoming more
and more based on science as distinguished from empiricism. I propose
on the present occasion to bring before you some illustrations of the
interdependence of science and the healing art ; and the first that I will
take is perhaps the most astonishing of all results of purely physical
inquiry—the discovery of the Réntgen rays, so called after the man who
first clearly revealed them to the world. Mysterious as they still are,
there is one of their properties which we can all appreciate—their power
of passing through substances opaque to ordinary light. There seems to
be no relation whatever between transparency in the common sense of

A

2 REPORT—1896.

the term and penetrability to these emanations. The glasses of a pair of
spectacles may arrest them while their wooden and leathern case allows
them to pass almost unchecked. Yet they produce, whether directly or
indirectly, the same effects as light upon a photographic plate. As a
general rule the denser any object is the greater obstacle does it oppose
to the rays. Hence, as bone is denser than flesh, if the hand or other
part of the body is placed above the sensitive film enclosed in a case of
wood or other light material at a suitable distance from the source of the
rays, while they pass with the utmost facility through the uncovered
parts of the lid of the box and powerfully affect the plate beneath, they
are arrested toa large extent by the bones, so that the plate is little
acted upon in the parts opposite to them, while the portions correspond-
ing to the muscles and other soft parts are influenced in an intermediate
degree. Thus a picture is obtained in which the bones stand out in sharp
relief among the flesh, and anything abnormal in their shape or position
is clearly displayed. ;

I need hardly point out what important aid this must give to the
surgeon. As an instance, I may mention a case which occurred in the
practice of Mr. Howard Marsh. He was called to see a severe injury of
the elbow, in which the swelling was so great as to make it impossible for
him by ordinary means of examination to decide whether he had to deal
with a fracture or a dislocation. If it were the latter, a cure would be
effected by the exercise of violence which would be not only useless but
most injurious if a bone was broken. By the aid of the Rontgen rays a
photograph was taken in which the bone of the upper arm was clearly

seen displaced forwards on those of the forearm. The diagnosis being thus —

established, Mr. Marsh proceeded to reduce the dislocation ; and his sue-
cess was proved by another photograph which showed the bones in their
natural relative position.

The common metals, such as lead, iron, and copper, being still denser
than the osseous structures, these rays can show a bullet embedded in a
bone or a needle lodged about a joint. At the last conversazione of the
Royal Society a picture produced by the new photography displayed
with perfect distinctness through the bony framework of the chest a half-
penny low down in a boy’s gullet. It had been there for six months,
causing uneasiness at the pit of the stomach during swallowing ; but
whether the coin really remained impacted, or if so, what was its position,
was entirely uncertain till the Rontgen rays revealed it. Dr. Macintyre
of Glasgow, who was the photographer, informs me that when the presence
of the halfpenny had been thus demonstrated, the surgeon in charge of the
case made an attempt to extract it, and although this was not successful
in its immediate object, it had the effect of dislodging the coin ; for a sub-
sequent photograph by Dr. Macintyre not only showed that it had disap-
peared from the gullet, but also, thanks to the wonderful penetrating
power which the rays had acquired in his hands, proved that it had not

ADDRESS, 3

lodged further down in the alimentary passage. The boy has since com-
pletely recovered.

The Rontgen rays cause certain chemical compounds to fluoresce, and
emit a faint light plainly visible in the dark ; and if they are made to fall
upon a translucent screen impregnated with such a salt, it becomes
beautifully illuminated. If a part of the human body is interposed
between the screen and the source of the rays, the bones and other
structures are thrown in shadow upon it, and thus a diagnosis can be
made without the delay involved in taking a photograph. It was in fact

_in this way that Dr. Macintyre first detected the coin in the boy’s gullet.
Mr. Herbert Jackson, of King’s College, London, early distinguished
himself in this branch of the subject. There is no reason to suppose that
the limits of the capabilities of the rays in this way have yet been reached.
By virtue of the greater density of the heart than the adjacent lungs
with their contained air, the form and dimensions of that organ in the
living body may be displayed on the fluorescent screen, and even its move-
ments have been lately seen by several different observers.

Such important applications of the new rays to medical practice have
strongly attracted the interest of the public to them, and I venture to
think that they have even served to stimulate the investigations of
physicists. The eminent Professor of Physics in the University College
of this city (Professor Lodge) was one of the first to make such practical
applications, and I was able to show to the Royal Society at a very early
period a photograph, which he had the kindness to send me, of a bullet
embedded in the hand. His interest in the medical aspect of the subject
remains unabated, and at the same time he has been one of the most dis-
tinguished investigators of its purely physical side.

There is another way in which the Réntgen rays connect themselves
with physiology, and may possibly influence medicine. It is found that
if the skin is long exposed to their action it becomes very much irritated,
affected with a sort of aggravated sun-burning. This suggests the idea
that the transmission of the rays through the human body may be not
altogether a matter of indifference to internal organs, but may, by long-
continued action, produce, according to the condition of the part con-
cerned, injurious irritation or salutary stimulation.

This is the jubilee of Anesthesia in surgery. That priceless blessing
to mankind came from America. It had, indeed, been foreshadowed in
the first year of this century by Sir Humphry Davy, who, having found
a toothache from which he was suffering relieved as he inhaled laughing
gas (nitrous oxide), threw out the suggestion that it might perhaps be
used for preventing pain in surgical operations. But it was not till, on
September 30, 1846, Dr. W. T. G. Morton, of Boston, after a series of
experiments upon himself and the lower animals, extracted a tooth pain-
lessly from a patient whom he had caused to inhale the vapour of sul-
phuric ether, that the idea was fully realised, He soon afterwards publicly

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4 REPORT—1896.

exhibited his method at the Massachusetts General Hospital, and after
that event the great discovery spread rapidly over the civilised world. I
witnessed the first operation in England under ether. It was performed by
Robert Liston in University College Hospital, and it was a complete success.
Soon afterwards I saw the same great surgeon amputate the thigh as
painlessly, with less complicated anwsthetie apparatus, by aid of another
‘ agent, chloroform, which was being powerfully advocated as a substitute
for ether by Dr. (afterwards Sir James Y.) Simpson, who also had the
great merit of showing that confinements could be conducted painlessly,
yet safely, under its influence. These two agents still hold the field as
general anesthetics for protracted operations, although the gas originally
suggested by Davy, in consequence of its rapid action and other advan-
tages, has taken their place in short operations, such as tooth extraction.
In the birthplace of anesthesia ether has always maintained its ground ;
but in Europe it was to a large extent displaced by chloroform till
recently, when many have returned to ether, under the idea that, though less
convenient, it is safer.. For my own part, I believe that chloroform, if
carefully administered on right principles, is, on the average, the safer
agent of the two.

The discovery of anesthesia inaugurated a new era in surgery. Not
only was the pain of operations abolished, but the serious and sometimes
mortal shock which they occasioned to the system was averted, while the
patient was saved the terrible ordeal of preparing to endure them. At
the same time the field of surgery became widely extended, since many

procedures in themselves desirable, but before impossible from the pro- _

tracted agony they would occasion, became matters of routine practice.
Nor have I by any means exhausted the list of the benefits conferred by
this discovery. '

Anesthesia in surgery has been from first to last a gift of science.
Nitrous oxide, sulphuric ether, and chloroform are all artificial products
of chemistry, their employment as anesthetics was the result of scientific

investigation, and their administration, far from being, like the giving of -

a dose of medicine, a matter of rule of thumb, imperatively demands the
vigilant exercise of physiological and pathological knowledge.

While rendering such signal service to surgery, anesthetics have
thrown light upon biology generally. It has been found that they exert
their soporific influence not only upon vertebrata, but upon animals so
remote in structure from man as bees and other insects. Even the fune-
tions of vegetables are suspended by their agency. They thus afford
strong confirmation of the great generalisation that living matter is of
the same essential nature wherever it is met with on this planet, whether
in the animal or vegetable kingdom. Anzsthetics have also, in ways to
which T need not here refer, powerfully promoted the progress of physio-
logy and pathology.

My next illustration may be taken from the work of Pasteur on fer-

—_—_— —_—_

ADDRESS. 5

mentation. The prevailing opinion regarding this class of phenomena
when they first engaged his attention was that they were occasioned
primarily by the oxygen of the air acting upon unstable animal or vege-
table products, which, breaking up under its influence, communicated
disturbance to other organic materials in their vicinity, and thus led to
their decomposition. Cagniard-Latour had indeed shown several years
before that yeast consists essentially of the cells of a microscopic fungus
which grows as the sweetwort ferments ; and he had attributed the break-
ing up of the sugar into alcohol and carbonic acid to the growth of the
micro-organism. In Germany Schwann, who independently discovered
the yeast plant, had published very striking experiments in support of
analogous ideas regarding the putrefaction of meat. Such views had
also found other advocates, but they had become utterly discredited,
largely through the great authority of Liebig, who bitterly opposed
them.

Pasteur, having been appointed as a young man Dean of the Faculty
of Sciences in the University of Lille, a town where the products of
alcoholic fermentation were staple articles of manufacture, determined to
study that process thoroughly ; and as a result he became firmly con-
vinced of the correctness of Cagniard-Latour’s views regarding it. In the
case of other fermentations, however, nothing fairly comparable to the
formation of yeast had till then been observed. This was now done by
Pasteur for that fermentation in which sugar is resolved into lactic acid
This lactic fermentation was at that time brought about by adding some
animal substance, such as fibrin, to a solution of sugar, together with
chalk that should combine with the acid as it was formed. Pasteur saw,
what had never before been noticed, that a fine grey deposit was formed,
differing little in appearance from the decomposing fibrin, but steadily
increasing as the fermentation proceeded. Struck by the analogy pre-
sented by the increasing deposit to the growth of yeast in sweetwort, he
examined it with the microscope, and found it to consist of minute
particles of uniform size. Pasteur was not a biologist, but although these
particles were of extreme minuteness in comparison with the constituents
of the yeast plant, he felt convinced that they were of an analogous
nature, the cells of a tiny microscopic fungus. This he regarded as the
essential ferment, the fibrin or other so-called ferment serving, as he
believed, merely the purpose of supplying to the growing plant certain
chemical ingredients not contained in the sugar but essential to its nutri-
tion. And the correctness of this view he confirmed in a very striking
manner, by doing away with the fibrin or other animal material altogether,
and substituting for it mineral salts containing the requisite chemical
elements. <A trace of the grey deposit being applied to a solution of
sugar containing these salts in addition to the chalk, a brisker lactic
fermentation ensued than could be procured in the ordinary way.

I have referred to this research in some detail because it illustrates

6 REPORT—1896.

Pasteur’s acuteness as an observer and his ingenuity in experiment, as
well as his almost intuitive perception of truth.

A series of other beautiful investigations followed, clearly proving that
all true fermentations, including putrefaction, are caused by the growth
of micro-organisms. “

Tt was natural that Pasteur should desire to know how the microbes
which he showed to be the essential causes of the various fermentations
took their origin. It was at that period a prevalent notion, even among
many eminent naturalists, that such humble and minute beings originated
de novo in decomposing organic substances ; the doctrine of spontaneous
generation, which had been chased successively from various positions
which it once occupied among creatures visible to the naked eye, having
taken its last refuge where the objects of study were of such minuteness
that their habits and history were correspondingly difficult to trace.
Here again Pasteur at once saw, as if by instinct, on which side the truth
lay ; and, perceiving its immense importance, he threw himself with ardour
into its demonstration. I may describe briefly one class of experiments
which he performed with this object. He charged a series of narrow-
necked glass flasks with a decoction of yeast, a liquid peculiarly liable to
alteration on exposure to the air. Having boiled the liquid in each flask,
to kill any living germs it might contain, he sealed its neck with a blow-
pipe during ebullition ; after which, the flask being allowed to cool, the
steam within it condensed, leaving a vacuum above the liquid. If, then,
the neck of the flask were broken in any locality, the air at that particular
place would rush in to fill the vacuum, carrying with it any living microbes
that might be floating in it. The neck of the flask having been again
sealed, any germs so introduced would in due time manifest their presence
by developing in the clear liquid. When any of such a series of flasks
were opened and re-sealed in an inhabited room, or under the trees of a
forest, multitudes of minute living forms made their appearance in them ;
but if this was done in a cellar long unused, where the suspended
organisms, like other dust, might be expected to have all fallen to the
ground, the decoction remained perfectly clear and unaltered. The oxygen
and other gaseous constituents of the atmosphere were thus shown to be of
themselves incapable of inducing any organic development in yeast-water.

Such is a sample of the many well-devised experiments by which he
carried to most minds the conviction that, as he expressed it, ‘la généra-
tion spontanée est une chimére,’ and that the humblest and minutest living
organisms can only originate by parentage from beings like themselves.

Pasteur pointed out the enormous importance of these humble
organisms in the economy of nature. It is by their agency that the dead
bodies of plants and animals are resolved into simpler compounds fitted
for assimilation by new living forms. Without their aid the world would
be, as Pasteur expresses it, encombré de cadavres. They are essential not
only to our well-being, but to our very existence, Similar microbes must

ADDRESS. ?

have discharged the same necessary function of removing refuse and
providing food for successive generations of plants and animals during the
past periods of the world’s history ; and it is interesting to think that
organisms as simple as can well be conceived to have existed when life first
appeared upon our globe have, in all probability, propagated the same
lowly but most useful offspring during the ages of geological time.

Pasteur’s labours on fermentation have had a very important influence
upon surgery. I have been often asked to speak on my share in this
matter before a public audience ; but I have hitherto refused to do so,
partly because the details are so entirely technical, but chiefly because I
have felt an invincible repugnance to what might seem to savour of self-
advertisement. The latter objection now no longer exists, since advancing
years have indicated that it is right for me to leave to younger men the
practice of my dearly loved profession. And it will perhaps be expected
that, if I can make myself intelligible, I should say something upon the
subject on the present occasion.

Nothing was formerly more striking in surgical experience than the
difference in the behaviour of injuries according to whether the skin was
implicated or not. ‘Thus, if the bones of the leg were broken and the
skin remained intact, the surgeon applied the necessary apparatus without
any other anxiety than that of maintaining a good position of the fragments,
although the internal injury to bones and soft parts might be very severe.
Tf, on the other hand, a wound of the skin was present communicating
with the broken bones, although the damage might be in other respects
comparatively slight, the compound fracture, as it was termed, was one of
the most dangerous accidents that could happen. Mr. Syme, who was, I
believe, the safest surgeon of his time, once told me that he was inclined to
think that it would be, on the whole, better if all compound fractures of
the leg were subjected to amputation, without any attempt to save the
limb. What was the cause of this astonishing difference? It was clearly
in some way due to the exposure of the injured parts to the external
world. One obvious effect of such exposure was indicated by the odour of
the discharge, which showed that the blood in the wound had undergone
putrefactive change by which the bland nutrient liquid had been converted
into highly irritating and poisonous substances. I have seen a man with
compound fracture of the leg die within two days of the accident, as
plainly poisoned by the products of putrefaction as if he had taken a fatal
dose of some potent toxic drug.

An external wound of the soft parts might be healed in one of two
ways. If its surfaces were ciean cut and could be brought into accurate
apposition, it might unite rapidly and painlessly ‘ by the first intention.’
This, however, was exceptional. Too often the surgeon’s efforts to obtain
primary union were frustrated: the wound inflamed and the retentive
stitches had to be removed, allowing it to gape ; and then, as if it had
been left open from the first, healing had to be effected in the other way

8 REPORT—1896.

which it is necessary for me briefly to deseribe. An exposed raw surface
became covered in the first instance with a layer of clotted blood or
certain of its constituents, which invariably putrefied ; and the irritation
of the sensitive tissues by the putrid products appeared to me to account
sutliciently for the inflammation which always occurred in and around an
open wound during the three or four days which elapsed before what were
termed ‘granulations’ had been produced. These constituted a coarsely
granular coating of very imperfect or embryonic structure, destitute of
sensory nerves and prone to throw off matter or pus, rather than absorb,
as freshly divided tissues do, the products of putrefaction. The granula-
tions thus formed a beautiful living plaster, which protected the sensitive
parts beneath from irritation, and the system generally from poisoning
and consequent febrile disturbance. The granulations had other useful
properties of which I may mention their tendency to shrink as they grew,
thus gradually reducing the dimensions of the sore. Meanwhile, another
cause of its diminution was in operation. The cells of the epidermis or
scarf-skin of the cutaneous margins were perpetually producing a crop of
young cells of similar nature, which gradually spread over the granulations
till they covered them entirely, and a complete cicatrix or scar was the
result. Such was the other mode of healing, that by granulation and
cicatrisation ; a process which, when it proceeded unchecked to its
completion, commanded our profound admiration. It was, however, essen-
tially tedious compared with primary union, while, as we have seen, it
was always preceded by more or less inflammation and fever, sometimes
very serious in their effects. It was also liable to unforeseen interruptions.
The sore might become larger instead of smaller, cicatrisation giving place
to ulceration in one of its various forms, or even to the frightful destruction
of tissue which, from the circumstance that it was most frequently met
with in hospitals, was termed hospital gangrene. Other serious and often
fatal complications might arise, which the surgeon could only regard as
untoward accidents and over which he had no efficient control.

It will be readily understood from the above description that the

inflammation which so often frustrated the surgeon’s endeavours after
primary union was in my opinion essentially due to decomposition of
blood within the wound.

These and many other considerations had long impressed me with the
grcatness of the evil of putrefaction in surgery. I had done my best to
mitigate it by scrupulous ordinary cleanliness and the use of various
deodorant lotions. But to prevent it altogether appeared hopeless while
we believed with Liebig that its primary cause was the atmospheric
oxygen which, in accordance with the researches of Graham, could not
fail to be perpetually diffused through the porous dressings which
were used to absorb the blood discharged from the wound. But when
Pasteur had shown that putrefaction was a fermentation caused by the
growth of microbes, and that these could not arise de novo in the

ADDRESS. 9

decomposable substance, the problem assumed a more hopeful aspect. If
the wound could be treated with some substance which, without doing too
serious mischief to the human tissues, would kill the microbes already con-
tained in it and prevent the future access of others in the living state,
putrefaction might be prevented, however freely the air with its oxygen
might enter. I had heard of carbolic acid as having a remarkable
deodorising effect upon sewage, and having obtained from my colleague
Dr. Anderson, Professor of Chemistry in the University of Glasgow, a
sample which he had of this product, then little more than a chemical
curiosity in Scotland, I determined to try it in compound fractures.
Applying it undiluted to the wound, with an arrangement for its
occasional renewal, I had the joy of seeing these formidable injuries follow
the same safe and tranquil course as simple fractures, in which the skin
remains unbroken.

At the same time we had the intense interest of observing in open
wounds what had previously been hidden from human view, the manner
in which subcutaneous injuries are repaired. Of special interest was the
process by which portions of tissue killed by the violence of the accident
were disposed of, as contrasted with what had till then been invariably
witnessed. Dead parts had been always seen to be gradually separated
from the living by an inflammatory process and thrown off as sloughs.
But when protected by the antiseptic dressing from becoming putrid and
therefore irritating, a structure deprived of its life caused no disturbance
in its vicinity ; and, on the contrary, being of a nutritious nature, it served
as pabulum for the growing elements of the neighbouring living structures,
and these became in due time entirely substituted for it. Even dead bone
was seen to be thus replaced by living osseous tissue.

’ This suggested the idea of using threads of dead animal tissue for tying
blood-vessels ; and this was realised by means of catgut, which is made
from the intestine of the sheep. If deprived of living microbes, and
otherwise properly prepared, catgut answers its purpose completely ; the
knot holding securely, while the ligature around the vessel becomes
gradually absorbed and replaced by a ring of living tissue. The threads,
instead of being left long as before, could now be cut short, and the
tedious process of separation of the ligature, with its attendant serious
danger of bleeding, was avoided.

Undiluted carbolie acid is a powerful caustic ; and although it might
be employed in compound fracture, where some loss of tissue was of little
moment in comparison with the tremendous danger to be averted, it was
altogether unsuitable for wounds made by the surgeon. It soon appeared,
however, that the acid would answer the purpose aimed at, though used
in diluted forms devoid of caustic action, and therefore applicable to
operative surgery. According to our then existing knowledge, two essen-
tial points had to be aimed at: to conduct the operation so that on its
completion the wound should contain no living microbes, and to apply a

A3

10 REPORT—1896.

dressing capable of preventing the access of other living organisms till
the time should have arrived for changing it.

Carbolic acid lent itself well to both these objects. Our experience
with this agent brought out what was, I believe, a new principle in
pharmacology—namely, that the energy of action of any substance upon
the human tissues depends not only upon the proportion in which it is
contained in the material used as a vehicle for its administration, but also
upon the degree of tenacity with which it is held by its solvent. Water
dissolves carbolic acid sparingly and holds it extremely lightly, leaving it
free to act energetically on other things for which it has greater affinity,
while various organic substances absorb it greedily and hold it tenaciously.
Hence its watery solution seemed admirably suited for a detergent lotion
to be used during the operation for destroying any microbes that might
fall upon the wound, and for purifying the surrounding skin and also the
surgeon’s hands and instruments. For the last-named purpose it had the
further advantage that it did not act on steel.

For an external dressing the watery solution was not adapted, as it
soon lost the acid it contained, and was irritating while it lasted. For
this purpose some organic substances were found to answer well. Large
proportions of the acid could be blended with them in so bland a form as
to be unirritating ; and such mixtures, while perpetually giving off
enough of the volatile salt to prevent organic development in the dis-
charges that flowed past them, served as a reliable store of the antiseptic
for days together.

The appliances which I first used for carrying out the antiseptic prin- -
ciple were both rude and needlessly complicated. The years that have
since passed have witnessed great improvements in both respects. Of
the various materials which have been employed by myself and others,
and their modes of application, I need say nothing except to express my
belief, as 2 matter of long experience, that carbolic acid, by virtue of its
powerful affinity for the epidermis and oily matters associated with it,
and also its great penetrating power, is still the best agent at our dis- ~
posal for purifying the skin around the wound. But I must say a
few words regarding a most important simplification of our procedure.
Pasteur, as we have seen, had shown that the air of every inhabited
room teems with microbes ; and for a long time I employed various inore
or less elaborate precautions against the living atmospheric dust, not
doubting that, as all wounds except the few which healed completely by
the first intention underwent putrefactive fermentation, the blood must
be a peculiarly favourable soil for the growth of putrefactive microbes.
But I afterwards learnt that such was by no means the case. I had
performed many experiments in confirmation of Pasteur’s germ theory,
not indeed in order to satisfy myself of its truth, but in the hope of
convincing others. I had observed that uncontaminated milk, which
would remain unaltered for an indefinite time if protected from dust,

ADDRESS. 1

was made to teem with microbes of different kinds by a very brief
exposure to the atmosphere, and that the same effect was produced by
the addition of a drop of ordinary water. But when I came to experi-
ment with blood drawn with antiseptic precautions into sterilised vessels,
I saw to my surprise that it might remain free from microbes in spite of
similar access of air or treatment with water. I even found that if very
putrid blood was largely diluted with sterilised water, so as to diffuse
its microbes widely and wash them of their acrid products, a drop of
such dilution added to pure blood might leave it unchanged for days at
the temperature of the body, although a trace of the septic liquid undi-
luted caused intense putrefaction within twenty-four hours. Hence I
was led to conclude that it was the grosser forms of septic mischief,
rather than microbes in the attenuated condition in which they existed
in the atmosphere, that we had to dread in surgical practice. And at
the London Medical Congress in 1881, I hinted, when describing the
experiments I have alluded to, that it might turn out possible to disre-
gard altogether the atmospheric dust. But greatly as I should have
rejoiced at such a simplification of our procedure, if justifiable, I did not
then venture to test it in practice. I knew that with the safeguards which
we then employed I could ensure the safety of my patients, andI did not
dare to imperil it by relaxing them. There is one golden rule for all
experiments upon our fellow-men. Let the thing tried be that which,
according to our best judgment, is the most likely to promote the welfare
of the patient. In other words, Do as you would be done by.

Nine years later, however, at the Berlin Congress in 1890, I was able
to bring forward what was, I believe, absolute demonstration of the harm-
lessness of the atmospheric dust in surgical operations. This conclusion
has been justified by subsequent experience : the irritation of the wound
by antiseptic irrigation and washing may therefore now be avoided, and
nature left quite undisturbed to carry out her best methods of repair,
while the surgeon may conduct his operations as simply as in former days,
provided always that, deeply impressed with the tremendous importance
of his object, and inspiring the same conviction in all his assistants, he
vigilantly maintains from first to last, with a care that, once learnt,
becomes instinctive, but for the want of which nothing else can compen-
sate, the use of the simple means which will suffice to exclude from the
wound the coarser forms of septic impurity.

Even our earlier and ruder methods of carrying out the antiseptic
principle soon produced a wonderful change in my surgical wards in the
Glasgow Royal Infirmary, which, from being some of the most unhealthy
in the kingdom, became, as I believe I may say without exaggeration, the
healthiest in the world ; while other wards, separated from mine only by
a passage a few feet broad, where former modes of treatment were for a while
continued, retained their former insalubrity. This result, I need hardly
remark, was not in any degree due to special skill on my part, but simply

12 REPORT—1896.

to the strenuous endeavour to carry out strictly what seemed to me a prin-
ciple of supreme importance.

Equally striking changes were afterwards witnessed in other institu-
tions. Of these I may give one example. In the great Allgemeines
Krankenhaus of Munich, hospital gangrene had become more and more
rife from year to year, till at length the frightful condition was reached
that 80 per cent. of all wounds became affected by it. It is only just to
the memory of Professor von Nussbaum, then the head of that. establish-
ment, to say that he had done his utmost to check this frightful scourge ;
and that the evil was not caused by anything peculiar in his management
was shown by the fact that in a private hospital under his care there was
no unusual unhealthiness. The larger institution seemed to have become
hopelessly infected, and the city authorities were contemplating its demo-
lition and reconstruction. Under these circumstances, Professor von
Nussbaum despatched his chief assistant, Dr. Lindpaintner, to Edinburgh,
where I at that time occupied the chair of clinical surgery, to learn the
details of the antiseptic system as we then practised it. He remained
until he had entirely mastered them, and after his return all the cases
were on a certain day dressed on our plan. From that day forward not
a single case of hospital gangrene occurred in the Krankenhaus. The
fearful disease pyemia likewise disappeared, and erysipelas soon followed
its example.

But it was by no means only in removing the unhealthiness of hos-
pitals that the antiseptic system showed its benefits. Inflammation being
suppressed, with attendant pain, fever, and wasting discharge, the suffer- -
ings of the patient were, of course, immensely lessened ; rapid primary
union being now the rule, convalescence was correspondingly curtailed ;
while as regards safety and the essential nature of the mode of repair, it
became a matter of indifference whether the wound had clean-eut surfaces
which could be closely approximated, or whether the injury inflicted had
been such as to cause destruction of tissue. And operations which had
been regarded from time immemorial as unjustifiable were adopted with ~
complete safety.

It pleases me to think that there is an ever-increasing number of prac-
titioners throughout the world to whom this will not appear the language
of exaggeration. There are cases in which, from the situation of the part
concerned or other unusual circumstances, it is impossible to carry out the
antiseptic system completely. These, however, are quite exceptional; and
even in them much has been done to mitigate the evil which cannot be
altogether avoided.

Task your indulgence if I have seemed to dwell too long upon matters
in which I have been personally concerned. I now gladly return to the
labours of others.

The striking results of the application of the germ theory to Surgery
acted as a powerful stimulus to the investigation of the nature of the

ADDRESS. 13

micro-organisms concerned ; and it soon appeared that putrefaction was
by no means the only evil of microbic origin to which wounds were liable.
Thad myself very early noticed that hospital gangrene was not necessarily
attended by any unpleasant odour; and I afterwards made a similar
observation regarding the matter formed in a remarkable epidemic of
erysipelas in Edinburgh cbviously of infective character. I had also seen
a careless dressing followed by the occurrence of suppuration without
putrefaction. And as these non-putrefactive disorders had the same self-
propagating property as ferments, and were suppressed by the same anti-
septic agencies which were used for combating the putrefactive microbes,
I did not doubt that they were of an analogous origin ; and I ventured
to express the view that, just as the various fermentations had each its
special microbe, so it might be with the various complications of wounds.
This surmise was afterwards amply verified. Professor Ogston, of Aber-
deen, was an early worker in this field, and showed that in acute abscesses,
that is to say those which run a rapid course, the matter, although often
quite free from unpleasant odour, invariably contains micro-organisms
belonging to the group which, from the spherical form of their elements,
are termed micrococci ; and these he classed as streptococci or staphylo-
cocci, according as they were arranged in chains or disposed in irregular
clusters like bunches of grapes. The German pathologist, Fehleisen, fol-
lowed with a beautiful research, by which he clearly proved that erysipelas
is caused by a streptococcus. A host of earnest workers in different
countries have cultivated the new science of Bacteriology, and, while
opening up a wide fresh domain of Biology, have demonstrated in so many
eases the causal relation between special micro-organisms and special
diseases, not only in wounds but in the system generally, as to afford
ample confirmation of the induction which had been made by Pasteur
that all infective disorders are of microbic origin.

Not that we can look forward with anything like confidence to being
able ever to see the materies morbi of every disease of this nature. One of
the latest of such discoveries has been that by Pfeiffer of Berlin of the
bacillus of influenza, perhaps the most minute of all micro-organisms ever
yet detected. The bacillus of anthrax, the cause of a plague common
among cattle in some parts of Europe, and often communicated to sorters
of foreign wool in this country, is a giant as compared with this tiny
being ; and supposing the microbe of any infectious fever to be as much
smaller than the influenza bacillus as this is less than that of anthrax, a
by no means unlikely hypothesis, it is probable that it would never be
visible to man. The improvements of the microscope, based on the
principle established by my father in the earlier part of the century,
have apparently nearly reached the limits of what is possible. But that
such parasites are really the causes of all this great class of diseases can

no longer be doubted.
The first rational step towards the prevention or cure of disease is to

ad

14 REPORT—1896.

know its cause ; and it is impossible to over-estimate the practical value
of researches such as those to which I am now referring. Among their
many achievements is what may be fairly regarded as the most important
discovery ever made in pathology, because it revealed the true nature of
the disease which causes more sickness and death in the human race than
any other. It was made by Robert Koch, who greatly distinguished
himself, when a practitioner in an obscure town in Germany, by the
remarkable combination of experimental acuteness and skill, chemical
and optical knowledge and successful micro-photography which he brought
to bear upon the illustration of infective diseases of wounds in the lower
animals ; in recognition of which service the enlightened Prussian
Government at once appointed him to an official position of great impor-
tance in Berlin. There he conducted various important researches; and
at the London Congress in 1881 he showed to us for the first time the
bacillus of tubercle. Wonderful light was thrown by this discovery upon
a great group of diseases which had before been rather guessed than known
to be of an allied nature ; a precision and efficacy never before possible
was introduced into their surgical treatment, while the physician became
guided by new and sure light as regards their diagnosis and prevention.
At that same London Congress Koch demonstrated to us his ‘ plate
culture’ of bacteria, which was so important that I must devote a few
words to its description. With a view to the successful study of the
habits and effects of any particular microbe outside the living body, it is
essential that it should be present unmixed in the medium in which it is

cultivated. It can be readily understood how difficult it must have been

to isolate any particular micro-organism when it existed mixed, as was
often the case, with a multitude of other forms. In fact, the various in-
genious attempts made to effect this object had often proved entire failures.
Koch, however, by an ingenious procedure converted what had been before
impossible into a matter of the utmost facility. In the broth or other
nutrient liquid which was to serve as food for the growing microbe he

dissolved, by aid of heat, just enough gelatine to ensure that, while it -

should beeome a solid mass when cold, it should remain fluid though re-
duced in temperature so much as to be incapable of killing living germs.
To the medium thus partially cooled was added some liquid containing,
among others, the microbe to be investigated ; and the mixture was
thoroughly shaken so as to diffuse the bacteria and separate them from
each other. Some of the liquid was then poured out in a thin layer upon
a glass plate and allowed to cool so as to assume the solid form. The
various microbes, fixed in the gelatine and so prevented from inter-
mingling, proceeded to develop each its special progeny, which in course
of time showed itself as an opaque speck in the transparent film. Any
one of such specks could now be removed and transferred to another vessel
in which the microbe composing it grew in perfect isolation.

Pasteur was present at this demonstration, and expressed his sense of

7

ADDRESS. 15

the great progress effected by the new method. It was soon introduced
into his own institute and other laboratories throughout the world ; and
it has immensely facilitated bacteriological study.

One fruit of it in Koch’s own hands was the discovery of the microbe
of cholera in India, whither he went to study the disease. This organism
was termed by Koch from its curved form the ‘comma bacillus,’ and by
the French the cholera vibrio. Great doubts were for a long time felt
regarding this discovery. Several other kinds of bacteria were found of
the same shape, some of them producing very similar appearances in cul-
ture media. But bacteriologists are now universally agreed that, although
various other conditions are necessary to the production of an attack of
cholera besides the mere presence of the vibrio, yet it is the essential
materies morbi ; and it is by the aid of the diagnosis which its presence in
any case of true cholera enables the bacteriologist to make, that threatened
invasions of this awful disease have of late years been so successfully
repelled from our shores. If bacteriology had done nothing more for us
than this, it might well have earned our gratitude.

I have next to invite your attention to some earlier work of Pasteur.
There is a disease known in France under the name of choléra des poules,
which often produced great havoc among the poultry yards of Paris. It
had been observed that the blood of birds that had died of this disease
was peopled by a multitude of minute bacteria, not very dissimilar in form
and size to the microbe of the lactic ferment to which I have before
referred. And Pasteur found that, if this bacterium was cultivated out-

_ side the body for a protracted period under certain conditions, it under-

went a remarkable diminution of its virulence ; so that, if inoculated into
a healthy fowl, it no longer caused the death of the bird, as it would have
done in its original condition, but produced a milder form of the disease
which was not fatal. And this altered character of the microbe, caused
by certain conditions, was found to persist in successive generations culti-
vated in the ordinary way. Thus was discovered the great fact of what
Pasteur termed the atténuation des virus, which at once gave the clue to
understanding what had before been quite mysterious, the difference in
virulence of the same disease in different epidemics.

But he made the further very important observation that a bird which
had gone through the mild form of the complaint had acquired immunity
against it in its most virulent condition. Pasteur afterwards succeeded
in obtaining mitigated varieties of microbes for some other diseases ; and
he applied with great success the principle which he had discovered in
fowl-cholera for protecting the larger domestic animals against the plague
of anthrax. The preparations used for such preventive inoculations he
termed ‘vaccins’ in honour of our great countryman, Edward Jenner.
For Pasteur at once saw the analogy between the immunity to fowl-
cholera produced by its attenuated virus and the protection afforded
against small-pox by vaccination. And while pathologists still hesitated,

16 REPORT—1896.

he had no doubt of the correctness of Jenner's expression variole vaccine,
or small-pox in the cow. ;

It is just a hundred years since Jenner made the crucial experiment of
inoculating with small-pox a boy whom he had previously vaccinated, the
result being, as he anticipated, that the boy was quite unaffected. It may
be remarked that this was a perfectly legitimate experiment, involving no
danger to the subject of it. Inoculation was at that time the established
practice ; and if vaccination should prove nugatory, the inoculation would
be only what would have been otherwise called for ; while it would be per-
fectly harmless if the hoped-for effect of vaccination had been produced.

We are a practical people, not much addicted to personal commemora-
tions : although our nation did indeed celebrate with fitting splendour the
jubilee of the reign of our beloved Queen ; and at the invitation of
Glasgow the scientific world has lately marked in a manner, though
different, as imposing, the jubilee of the life-work of a sovereign in science
(Lord Kelvin). But while we cannot be astonished that the centenary of
Jenner’s immortal discovery should have failed to receive general recogni-
tion in this country, it is melancholy to think that this year should, in his
native county, have been distinguished by a terrible illustration of the
results which would sooner or later inevitably follow the general neglect
of his prescriptions.

T have no desire to speak severely of the Gloucester Guardians. They
are not sanitary authorities, and had not the technical knowledge neces-
sary to enable them to judge between the teachings of true science and

the declamations of misguided, though well-meaning, enthusiasts. They

did what they believed to be right ; and when roused to a sense of the
greatness of their mistake, they did their very best to repair it, so that
their city is said to be now the best vaccinated in Her Majesty’s dominions.
But though by their praiseworthy exertions they succeeded in promptly
checking the raging epidemic, they cannot recall the dead to lite, or
restore beauty to marred features, or sight to blinded eyes. Would that
the entire country and our Legislature might take duly to heart this
object-lesson !

How completely the medical profession were convinced of the efficacy
of vaccination in the early part of this century was strikingly illustrated
by an account given by Professor Crookshank, in his interesting history of
this subject, of several eminent medical men in Edinburgh meeting to see
the to them unprecedented fact of a vaccinated person having taken small-
pox. It has, of course, since become well known that the milder form
of the disease, as modified by passing through the cow, confers a less
permanent protection than the original human disorder. This it was, of
course, impossible for Jenner to foresee. It is, indeed, a question of
degree, since a second attack of ordinary small-pox is occasionally known
to occur, and vaccination, long after it has ceased to give perfect immu-
nity, greatly modifies the character of the disorder and diminishes its

ADDRESS. aie)

danger. And, happily, in re-vaccination after a certain number of years
we have the means of making Jenner’s work complete. I understand
that the majority of the Commissioners, who have recently issued their
report upon this subject, while recognising the value and importance of
re-vaccination, are so impressed with the difficulties that would attend
making it compulsory by legislation that they do not recommend that
course ; although it is advocated by two of their number who are of
peculiarly high authority on such a question. I was lately told by a
Berlin professor that no serious difficulty is experienced in carrying out
the compulsory law that prevails in Germany. The masters of the
schools are directed to ascertain in the case of every child attaining the
age of twelve whether re-vaccination has been practised. If not, and
the parents refuse to have it done, they are fined one mark. If this does
not prove effectual, the fine is doubled : and if even the double penalty
should not prove efficacious, a second doubling of it would follow, but, as
my informant remarked, it is very seldom that it is called for. The
result is that small-pox is a matter of extreme rarity in that country ;
while it is absolutely unknown in the huge German army, in consequence
of the rule that every soldier is re-vaccinated on entering the service.
Whatever view our Legislature may take on this question, one thing
seems to me clear : that it will be the duty of Government to encourage
by every available means the use of calf lymph, so as to exclude the
possibility of the communication of any human disease to the child, and
to institute such efficient inspection of vaccination institutes as shall
ensure careful antiseptic arrangements, and so prevent contamination
by extraneous microbes. If this were done, ‘conscientious objections’
would cease to have any rational basis. At the same time, the ad-
ministration of the regulations on vaccination should be transferred (as
advised by the Commissioners) to competent sanitary authorities.

But to return to Pasteur. In 1880 he entered upon the study of
that terrible but then most obscure disease, Hydrophobia or Rabies, which
from its infective character he was sure must be of microbie origin,
although no micro-organism could be detected in it. He early demon-
strated the new pathological fact that the virus had its essential seat in
the nervous system. This proved the key to his success in this subject.
One result that flowed from it has been the cause of unspeakable consola-
tion to many. The foolish practice is still too prevalent of killing the dog
that has bitten any one, on the absurd notion that, if it were mad, its
destruction would prevent the occurrence of Hydrophobia in the person
bitten. The idea of the bare possibility of the animal having been so
affected causes an agony of suspense during the long weeks or months of
possible incubation of the disease. Very serious nervous symptoms aping
true Hydrophobia have been known to result from the terror thus inspired.
Pasteur showed that if a little of the brain or spinal cord of a dog that had
been really mad was inoculated in an appropriate manner into a rabbit, it

18 REPORT—1896.

infallibly caused rabies in that animal in a few days. If therefore such
an experiment was made with a negative result, the conclusion | migh
be drawn with certainty that the dog had been healthy. It is perhaps
right that I should say that the inoculation is painlessly done under an
aeccthictic: and that in the rabbit rabies does not assume the violent form
that it does in the dog, but produces gradual loss of power with little if
any suffering.

This is the more satisfactory because rabbits in which the disease has
been thus artificially induced are employed in carrying out what was
Pasteur’s greatest triumph, the preventive treatment of Hydrophobia in
the human subject. We have seen that Pasteur discovered that microbes
might under some circumstances undergo mitigation of their virulence.
He afterwards found that under different conditions they might have it
exalted, or, as he expressed it, there might be a renforcement du virus.
Such proved to be the case with rabies in the rabbit ; so that the spinal
cords of animals which had died of it contained the poison in a highly
intensified condition. But he also found that if such a highly virulent
cord was suspended under strict antiseptic precautions in a dry atmosphere
at a certain temperature, it gradually from day to day lost in potency, till
in course of time it became absolutely inert. If now an emulsion of such
a harmless cord was introduced under the skin of an animal, as in the
subcutaneous administration of morphia, it might be followed without harm
another day by a similar dose of a cord still rather poisonous ; and so from
day to day stronger and stronger injections might be used, the system
becoming gradually adoudtomed to the poison, till a degree of virulence .
had been reached far exceeding that of the bite of a mad dog. When this
had been attained, the animal proved incapable of taking the disease in
the ordinary way; and more than that, if such treatment was adopted
after an animal had already received the poison, provided that too long a
time had not elapsed, the outbreak of the disease was prevented. It was
only after great searching of heart that Pasteur, after consultation with
some trusted medical friends, ventured upon trying this practice upon ~
man. It has since been extensively adopted in various parts of the world
with increasing success as the details of the method were improved. It is
not of course the case that every one bitten by a really rabid animal takes
the disease ; but the percentage of those who do so, which was formerly
large, has been reduced almost to zero by this treatment, if not too long
delayed.

While the intensity of rabies in the rabbit is undoubtedly due to a
peculiarly virulent form of the microbe concerned, we cannot suppose that
the daily diminishing potency of the cord suspended in dry warm air is
an instance of attenuation of virus, using the term ‘ virus’ as synonymous
with the microbe concerned. In other words, we have no reason to
believe that the special micro-organism of hydrophobia continues to
develop in the dead cord and produce successively a milder and milder

ADDRESS. 19

progeny, Since rabies cannot be cultivated in the nervous system of a dead
animal. We must rather conclude that there must be some chemical
poison present which gradually loses its potency as time passes. And this
leads me to refer to another most important branch of this large subject
of bacteriology, that of the poisonous products of microbes.

It was shown several years ago by Roux and Yersin, working in the
Institut Pastewr, that the crust or false membrane which forms upon the
throats of patients affected with diphtheria contains bacteria which can
be cultivated outside the body in a nutrient liquid, with the result that it
acquires poisonous qualities of astonishing intensity, comparable to that
of the secrétion of the poison-glands of the most venomous serpents.
And they also ascertained that the liquid retained this property after the
microbes had been removed from it by filtration, which proved that the
poison must be a chemical substance in solution, as distinguished from the
living element which had produced it. These poisonous products of
bacteria, or toxins as they have been termed, explain the deadly effects of
some microbes, which it would otherwise be impossible to understand.
Thus, in diphtheria itself the special bacillus which was shown by Loffler
to be its cause, does not become propagated in the blood, like the microbe
of chicken cholera, but remains confined to the surface on which it first:
appeared : but the toxin which it secretes is absorbed from that surface
into the blood, and so poisons the system. Similar observations have
been made with regard to the microbes of some other diseases, as, for
example, the bacillus of tetanus or lockjaw. This remains localised in
the wound, but forms a special toxin of extreme potency, which becomes
absorbed and diffused through the body.

Wonderful as it seems, each poisonous microbe appears to form its
own peculiar toxin. Koch’s tuberculin was of this nature, a product of
the growth of the tubercle bacillus in culture media. Here, again, great
effects were produced by extremely minute quantities of the substance,
but here a new peculiarity showed itself, viz. that patients affected with
tubercular disease, in any of its varied forms, exhibited inflammation in
the affected part and general fever after receiving under the skin an
amount of the material which had no effect whatever upon healthy
persons. I witnessed in Berlin some instances of these effects, which
were simply astounding. Patients affected with a peculiar form of obsti-
nate ulcer of the face showed, after a single injection of the tuberculin,
violent inflammatory redness and swelling of the sore and surrounding
skin ; and, what was equally surprising, when this disturbance subsided
the disease was found to have undergone great improvement. By repeti-
tions of such procedures, ulcers which had previously been steadily
advancing, in spite of ordinary treatment, became greatly reduced in size,
and in some instances apparently cured. Such results led Koch to believe
that he had obtained an effectual means of dealing with tubercular disease
in all ‘ts forms. Unhappily, the apparent cure proved to be only of

20 REPORT—186. "3 5

transient duration, and the high hopes which had been inspired by Koch's

great reputation were dashed. It is but fair to say that he was strongly —
urged to publish before he was himself disposed to do so, and we cannot ,
but regret that he yielded to the pressure put upon him. :
But though Koch’s sanguine anticipations were not realised, it would
be a great mistake to suppose that his labours with tuberculin have been
fruitless. Cattle are liable to tubercle, and, when affected with it, may
become a very serious source of infection for human beings, more especially —
when the disease affects the udders of cows, and so contaminates the milk.
By virtue of the close affinity that prevails between the lower animals and
ourselves, in disease as well as in health, tuberculin produces fever in tuber-
cular cows in doses which do not affect healthy beasts. Thus, by the
subcutaneous use of a little of the fluid, tubercle latent in internal organs
of an apparently healthy cow can be with certainty revealed, and the
slaughter of the animal after this discovery protects man from infection.
It has been ascertained that glanders presents a precise analogy with
tubercle as regards the effects of its toxic products. If the microbe which
has been found to be the cause of this disease is cultivated in appropriate
media, it produces a poison which has received the name of mallein, and
the subcutaneous injection of a suitable dose of this fluid into a glandered
horse causes striking febrile symptoms which do not occur in a healthy
animal. Glanders, like tubercle, may exist in insidious latent forms
which there was formerly no means of detecting, but which are at once
disclosed by this means. If a glandered horse has been accidentally
introduced into a large stable, this method of diagnosis surely tells if it
has infected others. All receive a little mallein. Those which become
affected with fever are slaughtered, and thus not only is the disease pre-
vented from spreading to other horses, but the grooms are protected from
a mortal disorder.
This valuable resource sprang from Koch's work on tuberculin, which
has also indirectly done good in other ways. His distinguished pupil, —
Behring, has expressly attributed to those researches the inspiration of
the work which led him and his since famous collaborateur, the Japanese
Kitasato, to their surprising discovery of anti-toxic serum, They found
that if an animal of a species liable to diphtheria or tetanus received a
quantity of the respective toxin, so small as to be harmless, and after-
wards, at suitable intervals, successively stronger and stronger doses, the —
creature, in course of time, acquired such a tolerance for the poison as to —
be able to receive with impunity a quantity very much greater than
would at the outset have proved fatal. So far, we have nothing more
than seems to correspond with the effects of the increasingly potent cords
in Pasteur’s treatment of rabies. But what was entirely new in their
results was that, if blood was drawn from an animal which had acquired
this high degree of artificial immunity, and some of the clear fluid or
serum which exuded from it after it had clotted was introduced under the

ADDRESS. 21

skin of another animal, this second animal acquired a strong, though more
transient, immunity against the particular toxin concerned. The serum
in some way counteracted the toxin or was antitoxic. But, more than
that, if some of the antitoxic serum was applied to an animal after it had
already received a poisonous dose of the toxin, it preserved the life of the
creature, provided that too long a time had not elapsed after the poison
was introduced. In other words, the antitoxin proved to be not only
preventive but curative

Similar results were afterwards obtained by Ehrlich, of Berlin, with
some poisons not of bacterial origin, but derived from the vegetable
kingdom ; and quite recently the independent labours of Calmette of
Lille and Fraser of Edinburgh have shown that antidotes of wonderful
efficacy against the venom of serpents may be procured on the same prin-
ciple. Calmette has obtained antitoxin so powerful that a quantity of it
only a 200,000th part of the weight of an animal will protect it perfectly
against a dose of the secretion of the poison glands of the most venomous
serpents known to exist, which without such protection would have proved
fatal in four hours. For curative purposes larger quantities of the remedy are
required, but cases have been already published by Calmette in which death
appears to have been averted in the human subject by this treatment.

Behring’s darling object was to discover means of curing tetanus and
diphtheria in man. In tetanus the conditions are not favourable ; because
the specific bacilli lurk in the depths of the wound, and only declare their
presence by symptoms caused by their toxin having been already in a
greater or less amount diffused through the system ; and in every case of
this disease there must be a fear that the antidote may be applied too late
to be useful. But in diphtheria the bacilli very early manifest their pre-
sence by the false membrane which they cause upon the throat, so that
the antitoxin has a fair chance ; and here we are justified in saying that
Behring’s object has been attained.

The problem, however, was by no means so simple as in the case of
some mere chemical poison. However effectual the antitoxin might be
against the toxin, if it left the bacilli intact, not only would repeated
injections be required to maintain the transient immunity to the poison
perpetually secreted by the microbes, but the bacilli might by their growth
and extension cause obstruction of the respiratory passages.

Roux, however, whose name must always be mentioned with honour
in relation to this subject, effectually disposed of this difficulty. He
showed by experiments on animals that a diphtheritic false membrane,
rapidly extending and accompanied by surrounding inflammation, was
brought to a stand by the use of the antitoxin, and soon dropped off,
leaving a healthy surface. Whatever be the explanation, the fact was
thus established that the antitoxic serum, while it renders the toxin
harmless, causes the microbe to languish and disappear.

No theoretical objection could now be urged against the treatment ;

22 REPORT—1896.

and it has during the last two years been extensively tested in practice in
various parts of the world, and it has gradually made its way more and
more into the confidence of the profession. One important piece of evi-
dence in its favour in this country is derived from the report of the six
large hospitals under the management of the London Asylums Board.
‘The medical officers of these hospitals at first naturally regarded the prac-
tice with scepticism : but as it appeared to be at least harmless, they
gave it a trial ; and during the year 1895 it was very generally employed
upon the 2,182 cases admitted ; and they have all become convinced of
its great value. In the nature of things, if the theory of the treatment
is correct, the best results must be obtained when the patients are
admitted at an early stage of the attack, before there has been time
for much poisoning of the system : and accordingly we learn from the
report that, comparing 1895 with 1894, during which latter year the
ordinary treatment had been used, the percentage of mortality, in all
the six hospitals combined, among the patients admitted on the first day
of the disease, which in 1894 was 22-5, was only 4:6 in 1895; while for
those admitted on the second day the numbers are 27 for 1894 and 14:8
for 1895. Thus for cases admitted on the first day the mortality was
only one-fifth of what it was in the previous year, and for those enter-
ing on the second it was halved. Unfortunately in the low parts of
London which furnish most of these patients the parents too often delay
sending in the children till much later ;.so that on the average no less
than 67-5 per cent. were admitted on the fourth day of the disease or later.
Hence the aggregate statistics of all cases are not nearly so striking.
Nevertheless, taking it altogether, the mortality in 1895 was less than had
ever before been experienced in those hospitals. I should add that there
was no reason to think that the disease was of a milder type than usual
in 1895 ; and no change whatever was made in the treatment except as
regards the antitoxic injections.

There is one piece of evidence recorded in the report which, though it
is not concerned with high numbers, is well worthy of notice. It relates
to a special institution to which convalescents from scarlet fever are sent
from all the six hospitals. Such patients occasionally contract diphtheria,
and when they do so the added disease has generally proved extremely fatal.
In the five years preceding the introduction of the treatment with anti-
toxin the mortality from this cause had never been less than 50 per cent ,
and averaged on the whole 61-9 per cent. During 1895, under antitoxin,
the deaths among the 119 patients of this class were only 7-5 per cent.,
or one-eighth of what had been previously experienced. This very strik-
ing result seems to be naturally explained by the fact that these patients
being already in hospital when the diphtheria appeared, an unusually
early opportunity was afforded for dealing with it.

There are certain cases of so malignant a character from the first that
no treatment will probably ever be able to cope with them. But taking

% +

ADDRESS. 23

all’cases together it seems probable that Behring’s hope that the mortality
may be reduced to 5 per cent. will be fully realised when the public
become alive to the paramount importance of having the treatment com-
menced at the outset of the disease.

There are many able workers in the field of Bacteriology whose names
time does not permit me to mention, and to whose important labours I
cannot refer; and even those researches of which I have spoken have
been, of course, most inadequately dealt with. I feel this especially with
regard to Pasteur, whose work shines out more brightly the more his
writings are perused.

T have lastly to bring before you a subject which, though not bacterio-
logical, has intimate relations with bacteria. Ifa drop of blood is drawn
from the finger by a prick with a needle and examined microscopically
between two plates of glass, there are seen in it minute solid elements of
two kinds, the one pale orange bi-concave dises, which, seen in mass, give
the red colour to the vital fluid, the other more or less granular spherical
masses of the soft material called protoplasm, destitute of colour, and
therefore called the colourless or white corpuscles. It has been long
known that if the microscope was placed at such a distance from a fire as
to have the temperature of the human body, the white corpuscles might
be seen to put out and retract little processes or pseudopodia, and by their
means crawl over the surface of the glass, just like the extremely low
forms of animal life termed, from this faculty of changing their form,
ameebe. It was a somewhat weird spectacle, that of seeing what had
just before been constituents of our own blood moving about like inde-
pendent creatures. Yet there was nothing in this inconsistent with what
we knew of the fixed components of the animal frame. For example, the
surface of a frog’s tongue is covered with a layer of cells, each of which is
provided with two or more lashing filaments or cilia, and those of all the
cells acting in concert cause a constant flow of fluid in a definite direction
over the organ. If we gently scrape the surface of the animal’s tongue,
we can detach some of these ciliated cells ; and on examining them with
the microscope in a drop of water, we find that they will contiuue for an
indefinite time their lashing movements, which are just as much living or
vital in their character as the writhings of a worm. And, as I observed
many years ago, these detached cells behave under the influence of a
stimulus just like parts connected with the body, the movements of the
cilia being excited to greater activity by gentle stimulation, and thrown
into a state of temporary inactivity when the irritation was more severe.
Thus each constituent element of our bodies may be regarded as in one
sense an independent living being, though all work together in marvellous
harmony for the good of the body politic. The independent movements
of the white corpuscles outside the body were therefore not astonishing : but
they long remained matters of mere curiosity. Much interest was called to
them by the observation of the German pathologist Cohnheim that in some

24, REPORT—1896.

inflammatory conditions they passed through the pores in the walls of the
finest blood-vessels, and thus escaped into the interstices of the surrounding
tissues. Cohnheim attributed their transit to the pressure of the blood.
But why it was that, though larger than the red corpuscles, and contain-
ing a nucleus which the red ones have not, they alone passed through
the pores of the vessels, or why it was that this emigration of the white
corpuscles occurred abundantly in some inflammations and was absent
in others, was quite unexplained.

These white corpuscles, however, have been invested with extraordi-
nary new interest by the researches of the Russian naturalist and patholo-
gist, Metchnikoff. He observed that, after passing through the walls of
the vessels, they not only crawl about like amcebe, but, like them, receive
nutritious materials into their soft bodies and digest them. It is thus that
the effete materials of a tadpole’s tail are got rid of ; so that they play a
most important part in the function of absorption.

But still more interesting observations followed. He found that a
microscopic crustacean, a kind of water-flea, was liable to be infested
by a fungus which had exceedingly sharp-pointed spores. These were
apt to penetrate the coats of the creature’s intestine, and project into
its body-cavity. No sooner did this occur with any spore than it became
surrounded by a group of the cells which are contained in the cavity of
the body and correspond to the white corpuscles of our blood. These
proceeded to attempt to devour the spore; and if they succeeded, in
every such case the animal was saved from the invasion of the parasite.

But if the spores were more than could be disposed of by the devouring ~

cells (phagocytes, as Metchnikoff termed them), the water-flea succumbed.

Starting from this fundamental observation, he ascertained that the
microbes of infective diseases are subject to this same process of devouring
and digestion, carried on both by the white corpuscles and by cells that line
the blood-vessels. And by a long series of most beautiful researches he has,
as it appears to me, firmly established the great truth that phagocytosis

is the main defensive means possessed by the living body against the inva-

sions of its microscopic foes. The power of the system to produce anti-
toxic substances to counteract the poisons of microbes is undoubtedly in
its own place of great importance. But in the large class of cases in
which animals are naturally refractory to particular infective diseases the
blood is not found to yield any antitoxie element by which the natural
immunity can be accounted for. Here phagocytosis seems to be the sole
defensive agency. And even in cases in which the serum does possess
antitoxic, or, as it would seem in some cases, germicidal properties, the
bodies of the dead microbes must at last be got rid of by phagocytosis,
and some recent observations would seem to indicate that the useful
elements of the serum may be, in part at least, derived from the digestive
juices of the phagocytes. If ever there was a romantic chapter in
pathology, it has surely been that of the story of phagocytosis,

ADDRESS. 25

I was myself peculiarly interested by these observations of Metchni-
koff’s, because they seemed to me to afford clear explanation of the healing
of wounds by first intention under circumstances before incomprehensible.
This primary union was sometimes seen to take place in wounds treated
with water-dressing, that is to say, a piece of wet lint covered with a
layer of oiled-silk to keep it moist. , This, though cleanly when applied, was
invariably putrid within twenty-four hours. The layer of blood between the
cut surfaces was thus exposed at the outlet of the wound to a most potent
septic focus. How was it prevented from putrefying, as it would have
done under such influence if, instead of being between divided living
tissues, it had been between plates of glass or other indifferent material ?
Pasteur’s observations pushed the question a step further. It now was,
How were the bacteria of putrefaction kept from propagating in the
decomposable film? Metchnikoff’s phagocytosis supplied the answer.
The blood between the lips of the wound became rapidly peopled with
phagocytes, which kept guard against the putrefactive microbes and
seized them as they endeavoured to enter.

Tf phagocytosis was ever able to cope with septic microbes in so con-
centrated and intense a form, it could hardly fail to deal effectually with
them in the very mitigated condition in which they are present in the
air. We are thus strongly confirmed in our conclusion that the atmo-
spheric dust may safely be disregarded in our operations : and Metchni-
koff’s researches, while they have illumined the whole pathology of
infective diseases, have beautifully completed the theory of antiseptic
treatment in surgery.

T might have taken equally striking illustrations of my theme from other
departments in which microbes play no part. In fact any attempt to
speak of all that the art of healing has borrowed from science and con-
tributed to it during the past half-century would involve a very extensive
dissertation on pathology and therapeutics. I have culled specimens
from a wide field ; and I only hope that in bringing them before you I
have not overstepped the bounds of what is fitting before a mixed
company. For many of you my remarks can have had little if any
novelty : for others they may perhaps possess some interest as showing
that Medicine is no unworthy ally of the British Association—that, while
her practice is ever more and more based on science, the ceaseless efforts
of her votaries to improve what have been fittingly designated Que pro-
sunt omnibus artes, are ever adding largely to the sum of abstract
knowledge.

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of Science.

LIVERPOOL, 1896.

ADDRESS

TO THE

MATHEMATICAL AND PHYSICAL SECTION

BY

Proressor J. J. THOMSON, M.A., F.R.S.
PRESIDENT OF THE SECTION.

THERE is a melancholy reminiscence connected with this meeting of our Section,
for when the British Association last met in Liverpool the chair in Section A
was occupied by Clerk-Maxwell. In the quarter of a century which has elapsed
since that meeting, one of the most important advances made in our science has
been the researches which, inspired by Maxwell’s view of electrical action, con-
firmed that view, and revolutionised our conception of the processes occurring in
the Electro-magnetic field. When the Association last met in Liverpool Maxwell’s
view was almost without supporters, to-day its opponents are fewer than its sup-

orters then. Maxwell’s theory, which is the development and extension of
raaday’s, has not only affected our way of regarding the older phenomena of
electricity, it has, in the hands of Hertz and others, led to the discovery of whole
regions of phenomena previously undreamt of. It is sad to think that his prema-
ture death prevented him from reaping the harvest he had sown. His writings
are, however, with us, and are a storehouse to which we continually turn, and
never, I think, without finding something valuable and suggestive.

‘Thus ye teach us day by day,
Wisdom, though now far away.’

The past year has been rich in matters of interest to physicists. In it has
occurred the jubilee of Lord Kelvin’s tenure of the Professorship of Natural Philo-
sophy at the University of Glasgow. Some of us were privileged to see this year
at Glasgow an event unprecedented in the history of physical science in England,
when congratulations to Lord Kelvin on the jubilee of his professorship were
offered by people of every condition and country. Every scientific society and
every scientific man is Lord Kelvin’s debtor; but no society and no body of
men owe him a greater debt than Section A of the British Association ; he has
done more for this Section than any one else, he has rarely missed its meetings, he
has contributed to the Section papers which will make its proceedings imperishable,
and by his enthusiasm he has year by year inspired the workers in this Section to
renew with increased vigour their struggles to penetrate the secrets of nature,
Long may we continue to receive from him the encouragement and assistance
which have been so freely given for the past half century.

By the death of Sir W. R. Grove, the inventor of Grove’s cell, we have lost a
physicist whose name is a familiar one in every laboratory in the world. Besides
the Grove cell, we owe to him the discovery of the gas battery, and a series of re-
searches on the electrical behaviour of gases, whose importance is only now beginning

A

2 REPORT—1896,

to be appreciated. His essay on the correlation of the physical forces had great
influence in promoting that belief in the unity of the various branches of physics
which is one of the characteristic features of modern natural philosophy.

In the late Professor Stoletow, of Moscow, we have lost the author of a series
of most interesting researches on the electrical properties of gases illuminated b
ultra-violet light, researches which, from their place of publication, are, I am afraid,
not so well known in this country as they deserve to be.

As one who unfortunately of late years has had only too many opportunities of
judging of the teaching of science in our public and secondary schools, I should
like to bear testimony to the great improvement which has taken place in the
teaching of physics in these schools during the past ten years. The standard at-
tained in physics by the pupils of these schools is increasing year by year, and
great credit is due to those by whose labours this improvement has been accom-

lished. I hope I may not be considered ungrateful if I express the opinion that
in the zeal and energy which is now spent in the teaching of physics in schools,
there may lurk a temptation to make the pupils cover too much ground. You
may by careful organisation and arrangement ensure that boys shall be taken over
many branches of physics in the course of a short time; it is indeed not uncommon
to find boys of 17 or 18 who have compassed almost the whole range of physical
subjects. But although you may increase the rate at which information is ac-
quired, you cannot increase in anything like the same proportion the rate at which
the subject is assimilated, so as to become a means of strengthening the mind and
a permanent mental endowment when the facts have long been forgotten.

Physics can be taught so as to be a subject of the greatest possible educational
value, but when it is so it is not so much because the student acquires a knowledge
of a number of interesting and important facts, as by the mental training the study
affords in, as Maxwell said, ‘bringing our theoretical knowledge to bear on the
objects and the objects on our theoretical knowledge.’ I think this training can be
got better by going very slowly through such a subject as mechanics, making the
students try innumerable experiments of the simplest and, what is a matter of im-
portance in school teaching, of the most inexpensive kind, but always endeavouring

to arrive at numerical results, rather than by attempting to cover the whole range ~

of mechanics, light, heat, sound, electricity, and magnetism. I confess I regret the
presence in examinations intended for school boys of many of these subjects.
I think, too, that in the teaching of physics at our universities, there is perha:

a tendency to make the course too complex and too complete. I refer especially
to the training of those students who intend to become physicists. I think that
after a student has been trained to take accurate observations, to be alive to those
pitfalls and errors to which all experiments are liable, mischief may in some cases
be done if, with the view of learning a knowledge of methods, he is kept perform-
ing elaborate experiments, the results of which are well known. It is not given to
many to wear a load of learning lightly as a flower. With many students a load
of learning, especially if it takes a long time to acquire, is apt to crush enthusiasm.
Now, there is, I think, hardly any quality more essential to success in physical
investigations than enthusiasm. Any investigation in experimental physics
requires a large expenditure of both time and patience; the apparatus seldom,
if ever, begins by behaving as it ought; there are times when all the forces of
nature, all the properties of matter, seem to be fighting against us; the instruments
behave in the most capricious way, and we appreciate Coutts Trotter’s saying, that
the doctrine of the constancy of nature could never have been discovered in a labora-
tory. These difficulties have to be overcome, but it may take weeks or months to do
so, and, unless the student is enthusiastic, he is apt to retire disheartened from the
contest. I think, therefore, that the preservation of youthful enthusiasm is one of
the most important points forconsideration in the training of physicists. In my
opinion this can best be done by allowing the student, even before he is onppeats
to be acquainted with the whole of physics, to begin some original research of a
simple kind under the guidance of a teacher who will encourage him and assist in
the removal of difficulties. If the student once tastes the delights of the successful
completion of an inyestigation, he is not likely to go back, and will be better

TRANSACTIONS OF SECTION A. 3

uipped for investigating the secrets of nature than if, like the White Knight of
‘Alice in Wonderland,’ he commences his career knowing how to measure
or weigh every physical quantity under the sun, but with little desire or
enthusiasm to have anything to do with any of them. Even for those students
who intend to devote themselves to other pursuits than physical investigation, the
benefits derived from original investigation as a means of general education can
hardly be over-estimated, the necessity it entails of independent thought, perseve-
rance in overcoming difficulties, and the weighing of evidence gives it an educational
value which can hardly be rivalled. We have to congratulate ourselves that
through the munificence of Mr. Ludwig Mond, in providing and endowing a labora-
tory for research, the opportunities for pursuing original investigations in this country
have been greatly increased.

The discovery at the end of last year by Professor Réntgen of a new kind of
radiation from a highly exhausted tube deqae which an electric discharge is
passing, has aroused an amount of interest unprecedented in the history of physical
science. The effects produced inside such a tube by the cathode rays, tho
bright phosphorescence of the glass, the shadows thrown by opaque objects, the
deflection of the rays by a magnet, have, thanks to the researches of Crookes and
Goldstein, long been familiar to us, but it is only recently that the remarkable
effects which occur outside such a tube have been discovered. In 1893, Lenard,
using a tube provided with a window made of a very thin plate of aluminium,
found that a screen impregnated with a solution of a phosphorescent substance
became luminous if placed outside the tube in the prolongation of the line from the
cathode through the aluminium window. He also found that photographic plates

laced outside the tube in this line were affected, and electrified bodies were discharged ;

e also obtained by these rays photographs through plates of aluminium or quartz.
He found that the rays were altected by a magnet, and regarded them as the pro-
longations of the cathode rays. This discovery was at the end of last year followed
by that of Rontgen, who found that the region round the discharge tube is traversed
by rays which affect a photographic plate after passing through substances
such as aluminium or cardboard, which are opaque to ordinary light; which pass
from one substance to another, without any refraction, and with but little regular
reflection; and which are not affected by a magnet. We may, I think, for the
purposes of discussion, conveniently divide the rays occurring in or near a vacuum
tube traversed by an electric current into three classes, without thereby implying
that they are necessarily distinctly different in physical character. We have (1)
the cathode rays inside the tube, which are deflected by a magnet; (2) the Lenard
rays outside the tube, which are also deflected by a magnet; and (3) the Réntgen
rays, which are not, as far as is known, deflected by a magnet. Two views are held
as to the nature of the cathode rays; one view is, that they are particles of gas
carrying charges of negative electricity, and moving with great velocities which
Bey have acquired as they travelled through the intense electric field which exists
in the neighbourhood of the negative electrode, ‘lhe phosphorescence of the glass
is on this view produced by the impact of these rapidly moving charged particles,
though whether it is produced by the mechanical violence of the impact, or whether
it is due to an electro-magnetic impulse produced by the sudden reversal of the
velocity of the negatively charged particle—whether, in fact, it is due to mechanical
or electrical causes, is an open question. This view of the constitution of the
cathode rays explains in a simple way the deflection of those rays in a magnetic
field, and it has lately received strong confirmation from the results of an experiment
made by Perrin. Perrin placed inside the exhausted tube a cylindrical metal
vessel with a small hole in it, and connected this cylinder with the leaves of a gold-
leaf electroscope. ‘The cathode rays could, by means of a magnet, be guided so as
either to pass into the cylinder through the aperture, or turned quite away from it.
Perrin found that when the cathode rays passed into the cylinder the gold leaf of
the electroscope diverged, and had a negative charge, showing that the bundle of
cathode rays enclosed by the cylinder had a charge of negative electricity. Crookes
had many years ago exposed a disc connected with a gold-leaf electroscope to the
bombardment of the cathode rays, and found that the disc received a slight positive

4 REPORT—1896.

charge; with this arrangement, however, the charged particles had to give up their
charges to the dise if the gold leaves of the electroscope were to be affected, and we
know that it is extremely difficult, if not impossible, to get electricity out of a
charged gas merely by bringing the gas in contact with a metal. Lord Kelvin’s
electric strainers are an example of this. It is a feature of Perrin’s experiment
thatsince it acts by induction, the indications of the electroscope are independent
of the communication of the charges of electricity from the gas to the cylinder, and
since the cathode rays fall on the inside of the cylinder, the electroscope would
not be affected, even if there were such an effect as is produced when ultra-violet
light falls upon the surface of an electro-negative metal when the metal acquires a
ositive charge. Since any such process cannot affect the total amount of electricity
inside the cylinder, it will not affect the gold leaves of the electroscope; in fact,
Perrin’s experiments prove that the cathode rayscarry a charge of negative electricity.
The other view held as to the constitution of the cathode rays is that they are
waves in the ether. It would seem difficult to account for the result of Perrin’s
a alee on this view, and also I think very difficult to account for the magnetic
deflection of the rays. Let us take the case of a uniform magnetic field: the
experiments which have been made on the magnetic deflection of these rays seem
to make it clear that in a magnetic field which is-sensibly uniform, the path of
these rays is curved ; now if these rays were due to ether waves, the curvature of
the path would show that the velocity of propagation of these waves varied from
point to point of the path. That is, the velocity of propagation of these waves is
not only aflected by the magnetic field, it is affected differently at different parts
of the field. But in a uniform field what is there to differentiate one part
from another, so as to account for the variability of the velocity of wave
propagation in such a field? The curvature of the path in a uniform field
could not be accounted for by supposing that the velocity of this wave motion
depended on the strength of the magnetic field, or that the magnetic field,
by distorting the shape of the boundary of the negative dark space, changed
the direction of the wave front, and so produced a deflection of the rays. The
chief reason for supposing that the cathode rays are a species of wave motion is
afforded by Lenard’s discovery, that when the cathode rays in a vacuum tube fall -
on a thin aluminium window in the tube, rays having similar properties are
observed on the side of the window outside the tube; this is readily explained on
the hypothesis that the rays are a species of wave motion to which the window is
partially transparent, while it is not very likely that particles of the gas in the
tube could force their way through a piece of metal. This discovery of Lenard’s
does not, however, seem to me incompatible with the view that the cathode rays are
due to negatively charged particles moving with high velocities. The space outside
Lenard’s tube must have been traversed by Réntgen rays, these would put the

surrounding gas in a state in which a current would be readily started in the gas if ~

any electromotive force acted upon it. Now, though the metal window in Lenard’s
experiments was connected with the earth, and would, therefore, screen off from the
outside of the tube any effect arising from slow electrostatic changes in the tube, it
does not follow that it would be able to screen off the electrostatic effect of charged
particles moving to and from the tube with very great rapidity. For in order to
screen off electrostatic effects, there must be a definite distribution of electrification
over the screen; changes in this distribution, however, take a finite time, which
depends upon the dimensions of the screen and the electrical conductivity of the
material of which it is made. If the electrical changes in the tube take place at
above a certain rate, the distribution of electricity on the screen will not have time
to adjust itself, and the screen will cease to shield off all electrostatic effects. Thus
the very rapid electrical changes which would take place if rapidly moving charged
bodies were striking against the window, might give rise to electromotive forces
in the region outside the window, and produce convection currents in the gas
which has been made a conduetor by the Réntgen rays. The Lenard rays would
thus he analogous in character to the cathode rays, both being convective currents
of electricity. Though there are some points in the behaviour of these Lenard rays
which do not admit of a very ready explanation from this point of view, yet the

4

=?

TRANSACTIONS OF SECTION A. 5

difficulties in its way seem to me considerably less than that of supposing that a
wave in the ether can change its velocity when moving from point to point in a
uniform magnetic field.

I now pass on to the consideration of the Réntgen rays. We are not yet
{ acquainted with any crucial experiment which shows unmistakably that these rays
; are waves of transverse vibration in the ether, or that they are waves of normal

vibration, or indeed that they are vibrations at all. Asa working hypothesis, how-

ever, it may be worth while considering the question whether there is any property

known to be possessed by these rays which is not possessed by some form or other

- of light. The many forms of light have in the last few months received a note-

worthy addition by the discovery of M. Becquerel of an invisible radiation, possess-

ing many of the properties of the Réntgen rays, which is emitted by many fluores-

cent substances, and to an especially marked extent by the uranium salts. By

means of this radiation, which, since it can be polarised, is unquestionably light,

__ photographs through opaque substances similar to, though notso beautiful as, those

L obtained by means of Réntgen rays, can be taken, and, like the Réntgen rays, they

cause an electrified body on which they shine to lose its charge, whether this be
positive or negative.

The two respects in which the Réntgen rays differ from light is in the
absence of refraction and perhaps of polarisation. Let us consider the absence
of refraction first. We know cases in which special rays of the spectrum pass
from one substance to another without refraction; for example, Kundt showed
that gold, silver, copper allow some rays to pass through them without bending,
while other rays are bent in the wrong direction. Pfliiger has lately found that
the same is true for some of the aniline dyes when in a solid form. In addition to

§ this, the theory of dispersion of light shows that there will be no bending when the
uency of the vibration is very great. Ihave here a curve taken from a paper
by Helmholtz, which shows the relation between the refractive index and the
frequency of vibration for a substance whose molecules have a natural period of
vibration, and one only ; the frequency of this vibration is represented by OK in the
diagram. The refractive index increases with the frequency of the light until the
latter is equal to the frequency of the natural vibration of the substance; the
refractive index then diminishes, becomes less than unity, and finally approaches
unity, and is practically equal to it when the frequency of the light greatly exceeds
that of the natural vibration of the molecule. Helmholtz’s results are obtained on
the supposition that a molecule of the refracting substance consists of a pair of
oppositely electrified atoms, and that the specific inductive capacity of the medium
consists of two parts, one due to the ether, the other to the setting of the molecules

along the lines of electric force.

Starting from this supposition we can easily see without mathematical analysis
that the relation between the refractive index and the frequency must be of the
kind indicated by the curve. Let us suppose that an electromotive force of given
amplitude acts on this mixture of molecules and ether, and let us start with the fre-
quency of the external electromotive force less than that of the free vibrations of the
molecules : as theperiod of the force approaches that of the molecules, the effect of
the force in pokey the molecules into line will increase ; thus the specific inductive
capacity, and therefore the refractive index, increases with the frequency of the
external force ; the effect of the force on the orientation of the molecules will be

eatest when the period of the force coincides with that of the molecules, As

| age as the frequency of the force is less than that of the molecules, the external
field tends to make the molecules set so as to increase the specific inductive capacity

of the mixture; as soon, however, as the frequency of the force exceeds that of the
molecules, the molecules, if there are no viscous forces, will all topple over and
point so as to make the part of the specific inductive capacity due to the molecules
4 of opposite sign to that due to the ether. Thus, for frequencies greater than that

of the molecules, the specific inductive capacity will be less than unity. When the
frequency of the force only slightly eahadls that of the molecules, the effect of the
external field on the molecules is very great, so that if there are a considerable
number of molecules, the negative part of the specific inductive capacity due to the

6 REPORT—1896. .

>
molecules may be greater than the positive part due to the ether,sothatthe
specific inductive capacity of the mixture of molecules and ether would be negative;
no waves of this period could then travel through the medium, they would be
totally reflected from the surface. { oe

As the frequency of the force gets greater and greater, its effect in making the a 5
molecules set will get less and less, but the waves will continue to be totally re-
flected until the negative part of the specific inductive capacity due to the mole-—
cules is just equal to the positive part due to the ether. Here the refractive —
index of the mixture is zero. As the frequency of the force increases, its effecton —__
the molecules gets less and less, so that the specific inductive capacity continually
approaches that due to the ether alone, and practically coincides with it as soon as
the frequency of the force is a considerable multiple of that of the molecules. In
this case both the specific inductive capacity and the refractive index of the medium
are the same as that of the ether, and there is consequently no refraction, Thus
the absence of refraction, instead of being in contradiction to the Réntgen rays, —
being a kind of light, is exactly what we should expect if the wave length of the
light were exceedingly small.

The other objection to these rays being a kind of light is, that there is no very
conclusive evidence of the existence of polarisation. Numerous experiments have
been made on the difference between the absorption of these rays by a pair of —
tourmaline plates when their axes are crossed or parallel. Many observers have
failed to observe any difference at all between the absorption in the two cases.
Prince Galitzine and M. de Karnojitsky, by a kind of cumulative method, have
obtained photographs which seem to show that there is a slightly greater absorption
when the axes are crossed than there is when the axes are parallel. There can,
however, be no question that the effect, if it exists at all, is exceedingly small
compared with the corresponding effect for visible light. Analogy, however, leads
us to expect that to get polarisation effects we must use, in the case of short
waves, polarisers of a much finer structure than would be necessary for long ones.
Thus a wire bird-cage will polarise long electrical waves, but will have no effect
on visible light. Rubens and Du Bois made an instrument which would polarise
the infra red rays by winding very fine wires very close together on a framework ;
this arrangement, however, was too coarse to polarise visible light. Thus, though
the structure of the tourmaline is fine enough to polarise the visible rays, it may
be much too coarse to polarise the Réntgen rays if these have exceedingly small
waye-lengths. As far as our knowledge of these rays extends, I think we may
say that though there is no direct evidence that they are a kind of light, there are ~
no properties of the rays which are not possessed by some variety of light. -

It is clear that if the Réntgen rays are light rays, their wave-lengths are of an
entirely different order to those of visible light. It is perhaps worth notice that
on the electro-magnetic theory of light we might expect two different vr of
vibration if we suppose that the atoms in the molecule of the vibrating substance
carried electrical charges. One set of vibrations would be due to the oscillations
of the bodies carrying the charges, the other set to the oscillation of the charges
on these bodies. The wave-length of the second set of vibrations would be com-
mensurate with molecular dimensions; can these vibrations be the Rontgen rays ?
If so, we should expect them to be damped with such rapidity as to resemble
electrical impulses rather than sustained vibrations. F

If we turn from the rays themselves to the effects they produce, we find that
the rays alter the properties of the substances through which they are: passing. —
This change is most apparent in the effects produced on the electrical properties
of the substances. A gas, for example, while transmitting these rays is a con-
ductor of electricity. It retains its conducting properties for some little time
after the rays have ceased to pass through it, but Mr. Rutherford and I have
lately found that the conductivity is destroyed if a current of electricity is sent
through the Réntgenised gas. The gas in this state behaves in this respect like
a very dilute solution of an electrolyte. Such a solution would cease to conduct
after enough electricity had been sent through it to electrolyse all the molecules
of the electrolyte. When a current is passing through a gas exposed to the rays, —

a

- «4

TRANSACTIONS OF SECTION A, yi

the current destroys and the rays produce the structure which gives conductivity
to the gas; when things have reached a steady state the rate of destruction by the
current must equal the rate of production by the rays. The current can thus not
exceed a definite value, otherwise more of the conducting gas would be destroyed
than is produced.

This explains the very characteristic feature that in the passage of electricity
through gases exposed to Rontgen rays, the current, though at first proportional
to the electromotive force, soon reaches a value where it is almost constant and
independent of the electromotive force, and we get to a state when a tenfold
increase in the electromotive force only increases the current by a few per cent.
The conductivity under the Réntgen rays varies greatly from one gas to another,
the halogens and their gaseous compounds, the compounds of sulphur, and mereury
vapour, are among the best conductors, It is worthy of note that those gases
which are the best conductors when exposed to the rays are either elements, or
compounds of elements, which have in comparison with their valency very high
refractive indices.

The conductivity conferred by the rays on a gas is not destroyed by a con-
siderable rise in temperature; it is, for example, not destroyed if it be sucked
through metal tubing raised to a red heat. The conductivity is, however, de-
stroyed if the gas is made to bubble through water, it is also destroyed if the gas
is forced through a plug of glass wool. This last effect seems to indicate that the
structure which confers conductivity on the gas is of a very coarse kind, and we
get confirmation of this from the fact that a very thin layer of gas exposed to the

6ntgen rays does not conduct nearly so well as a thicker one. I think we have
evidence from other sources that electrical conduction is a process that requires
a considerable space—a space large enough to enclose a yery large number of
molecules.

Thus Koller found that the specific resistances of petroleum, turpentine,
and distilled water, when determined from experiments made with very thin
layers of these substances, was very much larger than when determined from ex-
periments with thicker layers. Even in the case of metals there is evidence that
the metal has to be of appreciable size if it is to conduct electricity. The theory
of the scattering of light by small particles shows that, if we assume the truth
of the electro-magnetic theory of light, the effects should be different according
as the small particles are insulators or conductors. When the small particles are
non-conductors, theory and experiment concur in showing that the direction of
complete polarisation for the scattered light is at right angles to the direction of
the incident light, while if the small particles are conductors, theory indicates
that the direction of complete polarisation makes an angle of 60° with the
incident light. This result is not, however, confirmed by the experiments made
by Professor Threlfall on the scattering of light by very small particles of gold.
He found that the gold scattered the light in just the same way as a non-
conductor, giving complete polarisation at right angles to the incident light.
This would seem to indicate that those very finely divided metallic particles no
longer acted as conductors. Thus there seems evidence that in the case of con-
duction through gases, through badly conducting liquids and through metals,
electric conduction is a process which requires a very considerable space and
aggregations of large numbers of molecules, I have not been able to find any
direct experimental evidence as to whether the same is true for electrolytes.
Experiments on the resistance of thin layers of electrolytes would be of con-
siderable interest, as according to one widely accepted view of electrolysis con-
duction through electrolytes, so far from being effected by aggregations of
molecules, takes place by means of the ion, a structure simpler than that of
the molecule, so that if this represents the process of electrolytic conduction,
there would not seem room for the occurrence of an effect which occurs with every
other kind of conduction.

Tn this building it is only fitting that some reference should be made to the

uestion of the movement of the ether. You are all doubtless acquainted with the
eroic attempts made by Professor Lodge to set the ether in motion, and how suc~

8 REPORT—1896.

cessfully the ether resisted them. It seems to be conclusively proved that a solid —
body in motion does not set in motion the ether at an appreciable distance outside
it; so that if the ether is disturbed at all in such a case, the disturbance is not com-
parable with that produced by a solid moving through an incompressible fluid, but
must be more analogous to that which would be produced by the motion through
the liquid of a body of very open structure, such as a piece of wire netting, where
the motion of the fluid only extends to a distance comparable with the diameter of
the wire, and not with that of the piece of netting. There is another class of
phenomena relating to the movement of the ether which is, I think, deserving of
consideration, and that is the effect of a varying electro-magnetic field in setti

the ether in motion. I do not remember to have seen it pointed out that the
electro-magnetic theory of light implicitly assumes that the ether is not set in
motion even when acted on by mechanical forces. On the electro-magnetic theory

of light such forces do exist, and the equations used are only applicable when the
ether is at rest. Consider, for example, the case of a plane electric wave travelling
through the ether. We have parallel to the wave front a varying electric polari-
sation, which on the theory is equivalent to a current; at right-angles to this, and
also in the wave-front, we have a magnetic force.. Now, when a current flows
through a medium in a magnetic field there is a force acting on the medium at
right-angles to the plane, which is parallel both to the current and to the magnetic
force; there will thus be a mechanical force acting on each unit volume of the
ether when transmitting an electric wave, and sinee this force is at right-angles to
the current and to the magnetic force, it will be in the direction in which the
wave is propagated. In the electro-magnetic theory of light, however, we assume
that this force does not set the ether in motion, as unless we made this assumption
we should have to modify our equations, as the electro-magnetic equations are not
the same in a moving field as in a field at rest. In fact, a complete discussion of
the transmission of electro-magnetic disturbances requires a knowledge of the con-
stitution of the ether which we do not possess. We now assume that the ether is
not set in motion by an electro-magnetic wave. If we do not make this assump-
tion we must introduce into our equation quantities representing the components _
of the velocity of the ether, and unless we know the constitution of the ether, so

as to be able to deduce these velocities from the forces acting on it, there will be

in the equations of the electro-magnetic field more unknown quantities than we
have equations to determine. It is, therefore, a very essential point in electro-
magnetic theory to investigate whether or not there is any motion of the ether in

a varying electro-magnetic field. We have at the Cavendish Laboratory, using
Professor Lodge's arrangement of interference fringes, made some experiments to
see if we could detect any movement of the ether in the neighbourhood of an
electric vibrator, using the spark which starts the vibrations as the source of light. -
The movement of the ether, if it exists, will be oscillatory, and with an undamped
vibrator the average velocity would be zero; we used, therefore, a heavily damped
vibrator, with which the average velocity might be expected to be finite. The
experiments are not complete, but so far the results are entirely negative. We also

tried by the same method to see if we could detect any movement of the ether in ]
the neighbourhood of a vacuum-tube emitting Réntgen rays, but could not find any
trace of such a movement. Professor Threlfall, who independently tried the same -

experiment, has, I believe, arrived at the same conclusion.

Unless the ether is immovable under the mechanical forces in a varying electro-
magnetic field, there are a multitude of phenomena awaiting discovery. If the
ether does move, then the velocity of transmission of electrical vibrations, and
therefore of light, will be affected by a steady magnetic field. Such a field, even if
containing nothing but ether, will behave towards light like a crystal, and the
velocity of propagation will depend upon the direction of the rays. A similar
result would also hold in a steady electric field. We may hope that experiments
on these and similar points may throw some light on the properties of that medium
which is universal, which plays so large a part in our explanation of physical
phenomena, and of which we know so little,

“Cane

British Association for the Advancement of
Science.

LIVERPOOL, 1896.

ADDRESS

TO THE

CHEMICAL SECTION

BY

Dr. LUDWIG MOND, F-.R.S.,

PRESIDENT OF THE SECTION.

In endeavouring to fix upon a suitable theme for the address I knew you
would to-day expect from me, I have felt that 1 ought to give due consideration
to the interests which tie this magnificent city of Liverpool, whose hospitality we
enjoy this week, to Section B. of the British Association.

I have therefore chosen to give you a brief history of the manufacture of
chlorine, with the progress of which this city and its neighbourhood have been
very conspicuously and very honourably connected, not only as regards quantity—
I believe this neighbourhood produces to-day nearly as much chlorine as the rest
of this world together—but more particularly by having originated, worked out,
and carried into practice several of the most important improvements ever intro-
duced into this manufacture. I was contirmed in my choice by the fact that this
manufacture has been influenced and perfected in an extraordinary degree by the
vapid assimilation and ah! Ss ion of the results of purely scientific investigations
and of new scientific theories, and offers a very remarkable example of the
incalculable value to our commercial interests of the progress of pure science.

The early history of chlorine is particularly interesting, as it played a most
important 7é/e in the development of chemical theories. There can be no doubt
that the Arabian alchemist Geber, who lived eleven hundred years ago, must have
lmown that ‘Aqua Regia,’ which he prepared by distilling a mixture of salt,
nitre, and vitriol, gave off on heating very corrosive, evil-smelling, greenish-
yellow fumes, and all his followers throughout a thousand years must have been
more or less molested by these fumes whenever they used Aqua Regia, the one
solvent of the gold they attempted so persistently to produce.

But it was not until 1774 that the great Swedish chemist Scheele succeeded
in establishing the character of these fumes. He discovered that on heating
manganese with muriatic acid he obtained fumes very similar to those given off
by ‘Aqua Regia, and found that these fumes constituted a permanent gas of
yellowish-green colour, very pungent odour, very corrosive, very irritating to the
respiratory organs, and which had the power of destroying organic colouring
matters,

According to the views prevalent at the time, Scheele considered that the
manganese had removed phlogiston from the muriatic acid, and he consequently
called the gas dephlogisticated muriatic acid.

When during the next decade Lavoisier successfully attacked, and after a
memorable struggle completely upset the phlogiston theory and laid the founda-
tions of our modern chemistry, Berthollet, the eminent ‘father’ of physical

B

02 REPORT—1896,

chemistry—the science of to-day—endeavoured to determine the place of Scheele’s
gas in the new theory. Lavoisier was of opinion that all acids, including muriatic
acid, contain oxygen. Berthollet found that a solution of Scheele’s gas in
water, when exposed to the sunlight, gives off oxygen and leaves behind muriatie
acid. He considered this as proof that this gas consists of muriatic acid and
oxygen, and called it oxygenated muriatic acid.

In the year 1785 Berthollet conceived the idea of utilising the colour-
destroying powers of this gas for bleaching purposes. He prepared the gas by
heating a mixture of salt, manganese, and vitriol. He used a solution of the
in water for bleaching, and subsequently discovered that the product obtained fie
absorbing the gas in a solution of caustic potash possessed great advantages in

ractice.

: This solution was prepared as early as 1789, at the chemical works on the
Quai de Javelle, in Paris, and is still made and used there under the name of
‘Bau de Javelle.’

James Watt, whose great mind was not entirely taken up with that greatest
of all inventions—his steam-engine—by which he has benefited the human race
more than any other man, but who also did excellent work in chemistry—became
acquainted in Paris with Berthollet’s process, and brought it to Scotland. Here
it was taken up with that energy characteristic of the Scotch, and a great stride
forward was made when, in 1798, Charles Tennant, the founder of the great firm,
which has only recently lapsed into the United Alkali Company, began to use
milk of lime in place of the more costly caustic potash, in making a bleaching
liquid; and a still greater advance was made when, in the following year,
Tennant proposed to absorb the chlorine by hydrate of lime, and thus to produce
a dry substance, since known under the name of bleaching powder, which allowed
the bleaching powers of chlorine to be transported to any distance.

In order to give you a conception of the theoretical ideas prevalent at this
time, I will read to you a passage from an interesting treatise on the art of
bleaching published in 1799 by Higgins. In his chapter ‘On bleaching with the
oxygenated muriatic acid, and on the methods of preparing it,’ he explains the
theory of the process as follows :— s

‘Manganese is an oxyd,a metal saturated with oxygen gas. Common salt is
composed of muriatic acid and an alkaline salt called soda, the same which barilla
affords. Manganese has greater affinity to sulphuric acid than to its oxygen, and
the soda of the salt greater affinity to sulphuric acid than to the muriatic acid
gas; hence it necessarily follows that these two gases (or rather their gravitating
matter) must be liberated from their former union in immediate contact with each
other ; and although they have but a weak affinity to one another, they unite in
their nascent state, that is to say, before they individually unite to caloric, and
separately assume the gaseous state; for oxygen gas and muriatic acid gas already
formed will not unite when mixed, in consequence principally of the distance at
which their respective atmospheres of caloric keep their gravitating particles
asunder. The compound resulting from these two gases still retains the property
of assuming the gaseous state, and is the oxygenated muriatic gas.’

Interesting as these views may appear, considering the time they were pub-
lished, you will notice that the rd/e played by the manganese in the process and
the chemical nature of this substance were not at all understood. The law of
multiple proportions had not yet been propounded by John Dalton, and the
researches of Berzelius on the oxides of manganese were only published thirteen
years later, in 1812. The green gas we are considering was still looked upon as
muriatic acid, to which oxygen had been added, in contradistinction to Scheele’s
view, who considered it as muriatic acid, from which something, viz. phlogiston,
had been abstracted. :

It was Humphry Davy who had, by a series of brilliant investigations carried
out in the Laboratory of the Royal Institution between 1808 and 1810, accumu-
lated fact upon fact to prove that the gas hitherto called oxygenated muriatic acid
did not contain oxygen. He announced in an historic paper, which he read before
the Royal Society on July 12, 1810, his conclusion that this gas was an elementary

-

-

TRANSACTIONS OF SECTION B. 3

body, which in muriatic acid was combined with hydrogen, and for which he
proposed the name ‘chlorine,’ derived from the Greek yAwpés, signifying ‘ green,’
the colour by which the gas is distinguished.

The numerous communications which Humphry Davy made to the Royal
Society on this subject form one of the brightest and most interesting chapters in
the history of chemistry. They have recently been reprinted by the Alembic
Society, and I cannot too highly recommend their study to the young students of
our science,

Those who have followed the history of chemistry I need not remind how hotly
and persistently Davy’s views were combated by a number of the most eminent
chemists of his time, led by Berzelius himself; how long the chlorine controversy
divided the chemical world ; how triumphantly Davy emerged from it ; how com-
pletely his views were recognised; and how very instrumental they have been in
advancing theoretical chemistry.

The hope, however, which Davy expressed in that same historic paper, ‘that
these new views would perhaps facilitate one of the greatest problems in economi-
cal chemistry, the decomposition of the muriates of soda and potash,’ was not to
be realised so soon. Although it had changed its name, chlorine was still for
many years manufactured by heating a mixture of salt, manganese, and sulphuric
acid in leaden stills, as before.

This process leaves a residue consisting of sulphate of soda and sulphate of
manganese, and for some time attempts were made to recover the sulphate of soda
from these residues, and to use it for the manufacture of carbonate of soda by the
Le Blane process. On the other hand, the Le Blanc process, which had been dis-
covered and put into practice almost simultaneously with Berthollet’s chlorine
process, decomposed salt by sulphuric acid, and sent the muriatic acid evolved
into the atmosphere, causing a great nuisance to the neighbourhood.

Naturally, therefore, when Mr. William Gossage had succeeded in devising
plant for condensing this muriatic acid, the manufacturers of chlorine reverted to
the original process of Scheele, and heated manganese with the muriatic acid thus
obtained. Since then the manufacture of chlorine has become a bye-product of
the manufacture of soda by the Le Blane process, and remained so till very
recently.

For a great many years the muriatic acid was allowed to act upon native ores
of manganese in closed vessels of earthenware or stone, to which heat could be
applied, either externally or internally. These native manganese ores, containing
only a certain amount of peroxide, converted only a certain percentage of the
muriatic acid employed into free chlorine, the rest combining with the manganese
and iron contained in the ore, and forming a brown and very acid solution, which
it was a great difficulty for the manufacturer to get rid of. Consequently, many
attempts were made to regenerate peroxide of manganese from these waste liquors,
so as to use it over again in the production of chlorine.

These, however, for a long time remained unsuccessful, because the exact
conditions for super-oxydising the protoxide of manganese by means of atmospheric
air were not yet known.

Meantime, viz. in 1845, Mr. Dunlop introduced into the works created by his
grandfather, Mr. Charles Tennant, at St. Rollox, a new and very interesting
method for producing chlorine, which was in a certain measure a return to the
process used by the alchemists.

Indeed, the first part of this process consisted in decomposing a mixture of
salt and nitre with oil of vitriol—a reaction that had been made use of for so many
centuries! The chlorine so obtained is, however, not pure, but a mixture of
chlorine with oxides of nitrogen and hydrochloric acid, which Mr. Dunlop had to
find means to eliminate.

For separating the nitrous oxides, Mr. Dunlop adopted the method introduced
twenty years before by the great Gay-Lussac in connection with vitriol-making,
viz. absorption by sulphuric acid, and the nitro-sulphuric acid thus formed he also
utilised in the same way as that obtained from the towers which still bear Gay-
Lussae’s illustrious name, viz. by using it in the vitriol process in lieu of nitric

4 REPORT—1896.

acid. Ife then freed his chlorine gas from hydrochloric acid hy washing with |

water, and so obtained it pure. This process possessed two distinct advantages—
(1) it yielded a very much larger amount of chlorine from the same amount of
salt, and (2) the nitric acid, which was used for oxidising the hydrogen in the
hydrochloric acid, was not lost, because the oxides of nitrogen to which it was
reduced answered the purpose for which the acid itself had previously been
employed. But this process was very limited in its application, as it could only
be worked to the extent to which nitric acid was used in vitriol-making.

The process has been at work at St. Rollox for over fifty years, and, as far as I
know, is there still in operation; but [am not aware that it has ever been taken
up elsewhere.

Within the last few years, however, several serious attempts have been made
to give to this process a wider scope by regenerating nitric acid from the nitro-
sulphuric acid and employing it over and over again to convert hydrochloric acid
into chlorine. Quite a number of patents have been taken out for this purpose, all
employing atmospheric air for reconverting the nitrous oxides into nitric acid, and
differing mainly in details of apparatus and methods of work, and several of these
have been put to practical test on a fairly large scale in this neighbourhood, and
also in Glasgow, Middlesbrough, and elsewhere. As I do not want to keep you
here the whole afternoon, I bave to draw the line somewhere as to what I shall
include in this brief history of the manufacture of chlorine, and have had to decide
to restrict myself to those methods which have actually attained the rank of
manufacturing processes on a large scale. As noneof the processes just referred
to have attained that position, you will excuse me for not entering into further
details respecting them.

Mr. Dunlop’s process only produced a very small portion of the chlorine
manufactured at that time at St. Rollox, the remainder being made, as before,
from native manganese and muriatic acid, leaving behind the very offensive waste
liquors I have mentioned before, which increased from year to year, and became
more and more difficult to get rid of. The problem of recovering from these liquors
the manganese in the form of peroxide Mr. Dunlop succeeded in solving in 1855.

He neutralised the free acid and precipitated the iron present by treating these
liquors with ground chalk in the cold and settling out, and in later years, filter-
pressing the precipitate, which left him a solution of chloride of manganese, mixed
only with chloride of calcium. This was treated with a fresh quantity of milk of
chalk, but this time under pressure in closed vessels provided with agitators and
heated by steam, under which conditions all the manganese was precipitated as
carbonate of manganese. This precipitate was filtered off and well drained, and
was then passed on iron trays mounted on carriages through long chambers, in
which it was exposed to hot air at a temperature of 300° C., the process being

practically made continuous, one tray at the one end being taken out of these”

chambers, and a fresh tray being put in at the other end. One passage through
these chambers sufficed to convert the carbonate of manganese into peroxide,
which was used in place of, and in the same way as, the native manganese.

The whole of the residual liquors made at the large works at St. Rollox have
heen treated by this process with signal success for a long number of years. For
a short time the process was discontinued in favour of the Weldon process (of
which I have to speak next); but after two years Dunlop's process was taken u
again, and to the best of mv knowledge it is still in operation to thisday. It
has, however, just like Mr Dunlop's first chlorine process, never left thé place of its
birth (St. Rollox), although it was for a period A pee ten years without a rival.

In 1866 Mr. Walter Weldon patented a modification of a process proposed
by Mr. William Gossage in 1837 for recovering the manganese that had been
used in the manufacture of chlorine. Mr. Gossage had proposed to treat the
residual liquors of this manufacture by lime, and to oxidise the resulting protoxide
of manganese by bringing it into frequent and intimate contact with atmospheric
air. This process—and several modifications thereof subsequently patented—had
been tried in various places without success. Mr. Weldon, however, did succeed
in obtaining a very satisfactory result, possibly—even probably—because, not

a

TRANSACTIONS OF SECTION B. 5

being a chemist, he did not add the equivalent quantity of lime to his liquor to
precipitate the manganese, but used an excess. However, Mr. Weldon, if he was
not a chemist at that time, was a man of genius and of great perseverance. He
soon made himself a chemist, and having once got a satisfactory result, he studied
every small detail of the reaction with the utmost tenacity until he had thoroughly
established how this satisfactory result could be obtained on the largest scale with
the greatest regularity and certainty.

e even went further, and added considerably to our theoretical knowledge of
the character of manganese peroxide and similar peroxides by putting forward the
view that these compounds possess the character of weak acids. He explained in
this way the necessity for the presence of an excess of lime or other base if the
oxidation of the precipitated protoxide of manganese by means of atmospheric air
was to proceed at a sufficiently rapid rate. He pointed out that the product had
to be considered as a manganite of calcium, a view which has since been
thoroughly proved by the investigations of Goergen and others; and it is only fair
to state that Weldon’s process is not only a process for recovering the peroxide of
manganese originally used, but that he introduced a new substance, viz. manga-
nite of calcium, to be continuously used over and over again in the manufacture of
chlorine.

Mr. Weldon had the good fortune that his ideas were taken up with fervency
by Colonel Gamble of St. Helens, and that Colonel Gamble’s manager, Mr. F.
Bramwell, placed all his experience as a consummate technical chemist and
engineer at Mr, Weldon’s disposal, and assisted him in carrying his ideas into
practice. The result was that a process which many able men had tried in vain
to realise for thirty years became in the hands of Mr, Weldon and his coadjutors
within a few years one of the greatest successes achieved in manufacturing
chemistry.

The Weldon proce&s commences by treating the residual liquor with ground
chalk or limestone, thus neutralising the free acid and precipitating any sulphuric
acid and oxide of iron present. The clarified liquor is run into a tall cylindrical
vessel, and milk of lime is added in sufficient quantity to precipitate’ all the
manganese in the form of protoxide. An additional quantity of milk of lime, from
one-fifth to one-third of the quantity previously used, is then introduced, and air
passed through the vessel by means of an air-compressor. After a few hours all
the manganese is converted into peroxide; the contents of the vessel are then run
off; the mud, now everywhere known as ‘ Weldon mud, is settled, and the clear
liquor run to waste. The mud is then pumped into large closed stone stills, where
it meets with muriatic acid, chlorine is given off, and the residual liquor treated
as before.

You note that this process works without any manipulation, merely by the
circulation of liquids and thick magmas which are moved by pumping machinery.
As compared to older processes it also has the great advantage that it requires
very little time for completing the cycle of operations, so that large quantities of
chlorine can be produced by a very simple and inexpensive plant. These advan-
tages secured for this process the quite unprecedented success that within a few
years it was adopted, with a few isolated exceptions, by every large manufacturer
of chlorine in the world; yet it possessed a distinct drawback, viz. that it pro-
duced considerably less chlorine from a given quantity of muriatic acid than either
native manganese of good quality or Mr. Dunlop’s recovered manganese, At that
time, however, muriatic acid was produced as a bye-product of the Le Blane pro-
cess so largely in excess of what could be utilised that it was generally looked
upon as a waste product of no value. Mr. Weldon himself was one of the very
few who foresaw that this state of things could not always continue. The am-
monia soda process was casting its shadow before it. Patented in 1838 by Messrs.
Dyar & Hemming it was only after the lapse of thirty years (during which a
number of manutacturing chemists of the highest standing had in vain endeavoured
to carry it into practice) that this process was raised to the rank of a manufactur-
ing process through the indomitable perseverance of Mr. Ernest Solvay of Brussels,
and his clear perception of its practical and theoretical intricacies. A few years

B2

6 REPORT—1896.

later, in 1872, Mr. Weldon already gave his attention to the problem of obtaining
the chlorine of the sult used in this process in the form of muriatic acid. He pro-
posed to recover the ammonia from the ammonium chloride obtained in this
manufacture by magnesia instead of lime, thus obtaining magnesium chloride
instead of calcium chloride, and to produce muriatic acid from this magnesium
chloride by a process patented by Clemm in 1863, viz. by evaporating the solution,
heating the residue in the presence of steam and condensing the acid vapours
given off.

Strange to say, this same method had been patented by Mr. Ernest Solvay
within twenty-four hours before Mr. Weldon lodged his specification. It has
been frequently tried with many modifications, but has never been found practic-
able. Soon afterwards Mr. Weldon, with the object of reducing the muriatie acid
required by his first process, proposed to replace the lime in this process by mag-
nesia, and so to produce a manganite of magnesia. After treating this with
muriatic acid and liberating chlorine he proceeded to evaporate the residual
liquors to dryness, during which operation all the chlorine they contain would be
disengaged as hydrochloric acid and collected in condensers, while the dry residue,
after being heated to dull redness in the presence of air, would be reconverted
into manganite of magnesia. :

This process was made the subject of long and extensive experiments at the
works of Messrs. Gamble at St. Helens, but did not realise Mr. Weldon’s expecta-
tions. It, however, led to some further interesting developments, to which I shall
refer later on. :

Those of you who were present at the last meeting of the British Association
in this city will remember that this Section had the advantage of listening to a
paper by Mr. Weldon on his chlorine process, and also to another highly interest-
ing paper by Mr. Henry Deacon of Widnes ‘on a new chlorine process without
munganese.’ And those of you who came with the then President of the Section
(Professor Roscoe) to Widnes to visit the works of Messrs. Gaskell, Deacon & Co.
will well remember that at these works they saw side by side Weldon’s process
and Deacon’s process in operation, and no one present will have forgotten the
thoughtful, flashing eyes and impressive face of Mr. Deacon when he explained to -
his visitors the theoretical views he had formed as regards his process.

Mr. Deacon had made a careful study of thermo-chemistry, which had been
greatly developed during the preceding decade by the painstaking, accurate, and
comprehensive experiments of Julius Thomsen and of Berthelot, and had led the
latter to generalisations, which, although not fully accepted by scientific men,
have been of immense service to manufacturing chemistry.

Mr. Deacon came to the conclusion that if a mixture of hydrochloric acid with
atmospheric air was heated in the presence of a suitable substance capable of
initiating the interaction of these two gases by its affinity to both, it would to a~
very great extent be converted into chlorine with the simultaneous formation of
steam, because the formation of steam from oxygen and hydrogen gives rise to the
evolution of a considerably larger quantity of heat than the combination of
hydrogen and chlorine. Mr. Deacon found that the salts of copper were a very
suitable substance for this purpose, and took out a patent for this process in 1868.
He entrusted the study of the theoretical and practical problems connected with
this process to Dr. Ferdinand Hurter, who carried them out in a manner which
will always remain memorable and will never be surpassed, as an example of the
application of scientific methods to manufacturing problems, and ‘which soon
placed this beautiful and simple process on a sound basis as a manufacturing
operation. ?

7 In the ordinary course of manufacture the major part—about two-thirds—of
the hydrochloric acid is obtained mixed with air and a certain amount of steam, but
otherwise very little contaminated. Instead of condensing the muriatic acid from
this mixture of gases by bringing it into contact with water, Mr. Deacon passed it
through a long series of cooling pipes to condense the steam, which of course
absorbed hydrochloric acid, and formed a certain quantity of strong muriatie
acid. The mixture of gases was then passed through an iron superheater to raise

TRANSACTIONS OF SECTION B. a

it to the required temperature, and thence through a mass of broken bricks im-
pregnated with sulphate or chloride of copper contained in a chamber or cylinder
called a decomposer, which was protected from loss of heat by being placed in a
brick furnace kept sufficiently hot. In this apparatus from 50 to 60 per cent. of
the hydrochloric acid in the mixture of gases was burnt to steam and chlorine. In
order to separate this chlorine from the steam and the remaining hydrochloric
acid the gases were washed with water, and subsequently with sulphuric acid.
The mixture now consisted of nitrogen and oxygen, containing about 10 per cent.
of chlorine gas, which could be utilised without any difficulty in the manufacture
of bleach liquors and chlorate of potash, and which Mr. Deacon also succeeded
in using for the manufacture of bleaching powder, by bringing it into contact
in specially constructed chambers with large surfaces of hydrate of lime.
Within recent years this latter object has been attained in a more expeditious and
Et manner by continuous mechanical apparatus (of which those constructed

y Mr. Robert Hasenclever and Dr. Carl Langer have been the most successful),
in which the hydrate of lime is transported in a continuous stream by single or
double conveyors in an opposite direction to the current of dilute chlorine, and the
bleaching powder formed delivered direct into casks, thereby avoiding the intensely
disesioaebip work of packing this offensive substance by hand.

Mr. Deacon's beautiful and scientific process thus involves still less movement
of materials than the very simple process of Mr. Weldon, because in lieu of large
volumes of liquids he only moves a current of gas through his apparatus, which
requires a minimum of energy. The only raw material used for converting hydro-
chloric acid into chlorine is atmospheric air, the cheapest of all at our command.
The hydrochloric acid which has not been converted into chlorine by the process is
all obtained, dissolved in water, as muriatic acid, and is not lost, as in previous
processes, but is still available to be converted into chlorine by other methods, or
to be used for other purposes.

In spite of these distinct advantages, this process took a long time before
it became adopted as widely as it undoubtedly deserved. This was mainly due to
the fact that the economy in the use of muriatic acid which it effected was at
the time when the process was brought out, and for many years afterwards, no
object to the majority of chlorine manufacturers, who were still producing more
of this commodity than they could use. Moreover, there were other reasons. The
plant required for this process, although so simple in principle, is very bulky
in proportion to the quantity of chlorine produced, and as I have pointed out, the
process only succeeded in converting about one-third of the hydrochloric acid
produced into chlorine, the remainder being obtained as muriatic acid, which had in
most instances to be converted into chlorine by the Weldon process; so that the
Deacon process did not constitute an entirely self-contained method for this
manufacture. This defect, of small moment as long as muriatic acid was produced
in excessive quantities, was only remedied by an invention of Mr. Robert
Hasenclever a short number of years ago; when by the rapid development of the
ammonia soda process the previously existing state of things had: been completely
changed, and when, at least on the Continent, muriatic acid was no longer an
Shdatiant and valueless bye-product, but, on the contrary, the alkali produced
by the Le Blanc process had become a bye-product of the manufacture of chlorine.
Mr. Hasenclever, in order to make the whole of the muriatic acid he produces avail-
able for conversion into chlorine by the Deacon process, introduces the liquid
wuriatic acid in a continuous stream into hot sulphuric acid contained in a series
of stone vessels, through which he passes a current of air. He thus obtains
a mixture of hydrochloric acid and air, well adapted for the Deacon process,
the water of the muriatic acid remaining with the sulphuric acid, from which it
is subsequently eliminated by evaporation. In this way the chlorine in the
hydrochloric acid can be almost entirely obtained in its free state by the simplest
imaginable means, and with the intervention of no other chemical agent than
atmospheric air. Since their introduction the Deacon process has supplanted the
Weldon process in nearly all the largest chlorine works in France and Germany,
and is now also making very rapid progress in this country.

8 REPORT—1896.

Mr. Weldon, when he decided to give up his manganite of magnesia process,
by no means relaxed his efforts to work out a chlorine process which should
utilise the whole of the muriatic acid. While working with manganite of
magnesia he found that magnesia alone would answer the purpose without the
presence of the capa of manganese. He obtained the assistance of M. Pechiney,
of Salindres, and in conjunction with him worked out what has become known as
the ‘ Weldon-Pechiney ’ process, which was first patented in 1884.

This process consists in neutralising muriatic acid by magnesia, concentrating
the solution to a point at which it does not yet give off any hydrochloric acid, and
then mixing into it a fresh quantity of magnesia so as to Bi fed a solid oxychloride
of magnesium. This is broken up into small pieces, which are heated up rapidly to a
high temperature without contact with the heating medium, while a current of
air is passing through them. The oxychloride of magnesium containing a large
quantity of water, this treatment yields a mixture of chlorine and hydrochloric
acid with air and steam, the same as the Deacon process, and this is treated in a
very similar way to eliminate the steam and the acid from the chlorine. The acid
condensed is, of course, treated with a fresh quantity of magnesia, so that the
whole of the chlorine which it contains is gradually obtained in the free state.

The rapid heating to a high temperature of the oxychloride of magnesium with-
out contact with the heating medium was an extremely difficult practical problem,
which has been solved by M. Pechiney and his able assistant, M. Boulouvard, in a
very ingenious and entirely novel way.

They lined a large wrought-iron box. with fire-bricks, and built inside of this
vertical fire-brick walls with small empty spaces between them, thus forming a
number of very narrow chambers, so arranged that they could all be filled from
the top of the box, and emptied from the bottom. These chambers they heated to
a very high temperature s passing a gas flame through them, thus storing up in
the brick walls enough heat to carry out and complete the decomposition of tke
magnesium oxychloride, with which the chamber was filled when hot enough.

Mr. Weldon himself called this apparatus a ‘baker's oven, in which trade
certainly the same principle has been employed from time immemoriai; but to my
knowledge it had never before been used in any chemical industry. This process
has been at work at M. Pechiney’s large alkali works at Salindres, and is now at
work in this country at the chlorate of potash works of Messrs. Allbright and
Wilson at Oldbury, a manufacture for which it offers special advantages. Mr.
Weldon and M. Pechiney had expected that this process would become specially
useful in connection with the ammonia soda process by preparing in the way pro-
posed by Mr. Solvay and Mr. Weldon in 1872 a solution of magnesium chloride
as a bye-product of this manufacture; but instead of obtaining muriatic acid from
this solution by Clemm’s process, to treat it by the new process, so as to obtain the
bulk of the chlorine at once in the free state. But M. Pechiney did no more suc-
ceed than his predecessors in recovering the ammonia by means of magnesia in a
satisfactory way.

Quite recently, however, it has been applied to obtain chlorine in connection
with the ammonia soda process by Dr. Pick, of Czakowa, in Austria. He recovers
the ammonia, as usual, by means of lime, and converts the solution of chloride of
calcium, obtained by a process patented by Mr. Weldon in 1869, viz. by treatment
with magnesia and carbonic acid under pressure, into chloride of magnesium with
the formation of carbonate of lime. The magnesium chloride solution is then con-
centrated and treated by the Weldon-Pechiney process. .

I have repeatedly referred during this brief history to the great change which
has been brought about in the position of chlorine manufacture by the develo
ment of the ammonia soda process, and have pointed out that the muriatic acid
which for a long time was the bye-product of the Le Blane process, without value,
thereby became gradually its main and most valuable product, while the alkali
became its bye-product.

I have told you how, very early in the history of this process, Mr. Solvay and
Mr. Weldon proposed means to provide for this contingency, and how Mr. Weldon
continued to improve these means until the time of his death. Mr. Solvay, on his

TRANSACTIONS OF SECTION B. 9

part, also followed up the subject with that tenacity and sincerity of purpose
which distinguishes him; his endeavours being mainly directed to producing
chlorine direct from the chloride of calcium running away from his works by mix-
ing it with clay and passing air through the mixture at very high temperatures,
thus producing chlorine and a silicate of calcium, which could be utilised in cement-
making. The very high temperatures required prevented, however, this process
from becoming a practical success.

I have already told you what a complicated series of operations Dr. Pick has
lately resorted to in order to obtain the chlorine from this chloride of calcium.
Yet the problem of obtaining chlorine as a bye-product of the ammonia soda process
presents itself as a very simple one.

This process produces a precipitate of bicarbonate of soda and a solution of
chloride of ammonium by treating natural brine or an artificially made solution of
salt, in which a certain amount of ammonia has been dissolved, with carbonic acid.
In their original patent of 1838 Messrs. Dyar & Hemming proposed to evaporate
this solution of ammonium chloride and to distil the resulting dry product with
lime to recover the ammonia. Now all that seemed to be necessary to obtain the
chlorine from this ammonium chloride was to substitute another oxide for lime in
the distillation process, which would liberate the ammonia and form a chloride
which on treatment with atmospheric air would give off its chlorine and reproduce
the original oxide. The whole of the reactions for producing carbonat® of soda
and bleaching powder from salt would thus be reduced to their simplest possible
form ; the solution of salt, as we obtain it in the form of brine direct from the svil,
would be treated with ammonia and carbonic acid to produce bicarbonate and
subsequently monocarbonate of soda, the limestone used for producing the carbonic
acid would yield the lime required for absorbing the chlorine, and produce bleaching
powder instead of being run into the rivers in combination with chlorine in the
useless form of chloride of calcium, and both the ammonia used as an intermediary
in the production of soda and the metallic oxide used as an intermediary in the
production of chlorine would be continuously recovered.

The realisation of this fascinating problem has occupied me for a great many
years. In the laboratory I obtained soon almost theoretical results. A very large
number of oxides and even of salts of weak acids were found to decompose
ammonium chloride in the desired way ; but the best results (as was to be clearly
anticipated from thermo-chemical data) were given by oxide of nickel.

When, however, I came to carry this process out on a large scale, I met with
the most formidable difficulties, which it took many years to overcome successfully.

The very fact that ammonium chloride vapour forms so readily metallic chlo-
rides when brought in contact at an elevated temperature with metals or oxides
or even silicates, led to the greatest difficulty, viz. that of constructing apparatus
which would not be readily destroyed by it.

Amongst the metals we found that platinum and gold were the only ones not
attacked at all. Antimony was but little attacked, and nickel resisted very well if
not exposed to too high a temperature, so that it could be, and is being, used for
such parts of the plant as are not directly exposed to heat. The other parts of the
apparatus coming in contact. with the ammonium chloride vapour I ultimately
succeeded in constructing of cast and wrought iron, lined with fire-bricks or
Doulton tiles, the joints between these being made by meansof a cement consisting
of sulphate of baryta and waterglass.

After means had been devised for preventing the breaking of the joints
through the unequal expansion of the iron and the earthenware, the plant so
constructed has lasted very well.

Oxide of nickel, which had proved the most suitable material for the process in
the laboratory, gave equally good chemical results on the large scale, but occasion-
ally a small quantity of nickel chloride was volatilised through local over-heating,
which, however, was sufficient to gradually make up the chlorine conduits. We
therefore looked out for an active material free from this objection. Theoretical
considerations indicated magnesia as the next best substance, but it was found that
the magnesium chloride formed was not anhydrous, but retained a certain amount

10 REPORT—1896.

of the steam formed by the reaction, which gave rise to the formation of a con-
siderable quantity of hydrochloric acid on treatment with hot air. In conjunction
with Dr. Eschellman (who carried out the experiments for me), I succeeded in
reducing the quantity of this hydrochloric acid to a negligible amount by adding
to the magnesia a certain amount of chloride of potassium, which probably has the
effect of forming an anhydrous double chloride.

This mixture of magnesia and potassium chloride is, after the addition of a
certain quantity of china clay, made into small pills in order to give a free and
regular passage throughout their entire mass to the hot air and other gases with
which they have to be treated. In order to avoid as far as possible the handling
and consequent breaking of these pills, I vapourise the ammonium chloride in a
special apparatus, and take the vapours through these pills and subsequently pass
hot air through, and then again ammonium chloride vapour, and so on, without
the pills changing their place.

The vapourisation of the ammonium chloride is carried out in long cast-iron
retorts lined with thin Doulton tiles, and placed almost vertically in a furnace
which is kept by producer gas at a very steady and regular temperature. These
retorts are kept nearly full with ammonium chloride, so as to have as much active
heating surface as possible. From time to time a charge of ammonium chloride is
introduced through a hopper at the top of these retorts, which is closed by a nickel
plug. The ammonium chloride used is very pure, being crystallised out from its
solution as produced in the ammonia soda manufacture by a process patented by
Mr. Gustav Jarmay, which consists in lowering the temperature of these solutions
considerably below 0° C. by means of refrigerating machinery. The retorts will
therefore evaporate a very large amount of ammonium chloride before it becomes
necessary to take out through a door at their bottom the non-volatile impurities which
accumulate in them. The ammonium chloride vapour is taken from these retorts
by cast-iron pipes lined with tiles and placed in a brick channel,in which they are kept
hot, to prevent the solidification of the vapour, to large upright wrought-iron eylin-
ders which are lined with a considerable thickness of fire-bricks, and are filled with
the magnesia pills, which are, from the previous operations, left at a temperature
of about 300°C. On its passage through the pills the chlorine in the vapours is ~
completely retained by them, the ammonia and water vapour formed pass on and
are taken to a suitable condensing apparatus. The reaction of the ammonium
chloride vapour upon magnesia being exo-thermic, the temperature of the pills
rises during this operation, and no addition of heat is necessary to complete it.
The temperature, however, does not rise sufficiently to satisfactorily complete the
second operation, viz. the liberation of the chlorine and the re-conyersion of the
magnesium chloride into magnesium oxide by means of air. This reaction is
slightly endo-thermic, and thus absorbs a small amount of heat, which has to be |
haa in one way or another. I effect this by heating the pills to a somewhat

igher temperature than is required for the action of the air upon them, viz. to
600° C., by passing through them a current of a dry inert gas free from oxygen
heated by a Siemens-Cowper stove to the required temperature. I use for this
purpose the gas leaving the carbonating plant of the ammonia soda process.

This current of gas also carries out of the apparatus the small amount of
ammonia which was left in between the pills. It is washed to absorb this
ammonia, and after washing, this same gas is passed again through the Siemens-
Cowper stove, and thus constantly circulated through the apparatus, taking up the
heat from the stove and transferring it to the pills. When these have attained the
required temperature, the hot inert gas is stopped and a current of hot air passed
through, which has also been heated to 600° C. in a similar stove. The air acts
rapidly upon the magnesium chloride, and leaves the apparatus charged with 18 to
20 per cent. of chlorine and a small amount of hydrochloric acid. The chlorine
comes gradually down, and when it has reached about 3 per cent. the temperature
of the air entering the apparatus is lowered to 350° C. by the admixture of cold
air to the hot air from the stove; and the weak chlorine leaving the apparatus 1s
passed through a second stove, in which its temperature is raised again to 600° C.,
and passed into another cylinder full of pills which are just ready to receive the

TRANSACTIONS OF SECTION B. 11

hot-air current. A series of four cylinders is required to procure the necessary
continuity for the process.

The chlorine gas is washed with a strong solution of chloride of calcium,
which completely retains all the hydrochloric acid, and is then absorbed in an
apparatus invented by Dr. Carl Langer, by hydrate of lime, which is made to pass
hy a series of interlocked transporting twin-screws in an opposite direction to the
current of gas, and produces very good and strong bleaching powder, in spite of
the varying strength of the chlorine gas. The hydrochloric acid absorbed by the
solution of calcium chloride can by heating this solution be readily driven out and
collected.

This process has now been in operation on a considerable scale at our Works at
Winnington for several years, with constantly improving results, notably with
regard to the loss of ammonia, which has gradually been reduced to a small
amount. The process has fully attained my object, viz. to enable the ammonia
soda process to compete, not only in the production of carbonate of soda, but also
in the production of bleaching powder, with the Le Blanc process.

Nevertheless, I have hesitated to extend this process as rapidly as I should
otherwise have done, because very shortly after I had overcome all its difficulties,
entirely different methods from those hitherto employed for the manufacture of
chlorine were actively pushed forward in different parts of the globe, for which
great advantages were claimed, but the real lg and capabilities of which
were and are up to this date very difficult to judge. I refer to the processes for
producing chlorine by electrolysis.

During the first decade of this century, Humphry Davy had by innumerable
experiments established all the leading facts concerning the decomposing action of
an electric current upon chemical compounds. Amongst these he was the first to
discover that solutions of alkaline chlorides, when submitted to the action of a
current, yield chlorine. His successor at the Royal Institution, Michael Faraday,
worked out and proved the fundamental law of electrolysis, known to everybody
as ‘Faraday’s Law,’ which has enabled us to calculate exactly the amount of
current required to produce by electrolysis any detinite quantity of chlorine.
Naturally, since these two eminent men had so clearly shown the way, numerous
inventors have endeavoured to work out processes based on these principles for the
production of chlorine on a manufacturing scale, but only during the last few years
have these met with any measure of success.

It has taken all this time for the classical work of Faraday on electro-mag-
netism to develop into the modern en sees ta machine, capable of producing
electricity in sufficient quantity to make it available for chemical operations on a
large scale; for you must keep in mind that an electric installation sufficient to
light a ree town will only produce a very moderate quantity of chemicals.

In applying electricity to the production of chlorine, various ways have been
followed, both as to the raw materials and as to the apparatusemployed. While
most inventors have proposed to electrolyse a solution of chloride of sodium, and
to produce thereby chlorine and caustic soda, I am not aware that up to this day
any quantity of caustic soda made by electrolysis has been put on to the market.

Only two electrolytic works producing chlorine on a really large scale are in
operation to-day. Both electrolyse chloride of potassium, producing as a bye-
product caustic potash, which is of very much higher value than caustic soda, and
of which a larger quantity is obtained for the same amount of current expended.
These works are situated in the neighbourhood of Stassfurt, the important centre
of the chloride of potassium manufacture. The details of the plant they employ
are kept secret, but it is known that they use cells with porous diaphragms of
special construction, for which great durability is claimed. There are at this
moment a considerable number of smaller works in existence, or in course of
erection in various countries, intended to carry into practice the production of
chlorine by electrolysis by numerous methods, differing mainly in the details of
the cells to be used ; but some of them also involving what may be called new prin-
ciples. The most interesting of these are the processes in which mercury is used
alternately as cathode and anode, and salt as electrolyte. They aim at obtaining

12 REPORT—1896,

in the first instance chlorine and an amalgam of sodium, and subsequently con-
verting the latter into caustic soda by contact with water, which certainly has
the advantage of producinga very pure solution of caustic soda. Mr. Hamilton
Castner has rae out this idea most successfully by a very beautiful decomposing
cell, which is divided into various compartments, and so arranged that by slightly
rocking the cell the mercury charged with sodium in one compartment passes into
another, where it gives up the sodium to water, and then returns to the first com-
partment, to be recharged with sodium. His process has been at work on a
small seale for some time at Oldbury near Lirmingham, and works for carrying
it out on a large scale are now being erected on the banks of the Mersey, and also
in Germany and America.

Entirely different from the foregoing, but still belonging to our subject, are
metnods which propose to electrolyse the chlorides of heavy metals (zine, lead,
copper, &c.) obtained in metallurgical operations or specially prepared for the pur-
pose, among which the processes of Dr. Carl Hoepfner deserve special attention.
‘They eliminate from the electrolyte immediately both the products of electrolysis,
chlorine on one side and zine and copper on the other, and thus avoid all secondary
reactions, which have been the great difliculty in the electrolysis of alkaline
chlorides. :

All these processes have, however, still to stand the test of time before a final
opinion can be arrived at as to the effect they will have upon the manufacture of
chlorine, the history of which we have been following, and this must be my excuse
for not going into further details. I have endeavoured to give you a brief history
of the past of the manufacture of chlorine, but I will to-day not attempt to deal
with its future! Yet 1 cannot leave my subject without stating the remarkable
fact that every one of these processes which I have described to you is still at work
to this day, even those of Scheele and Berthollet, all finding a sphere of usefulness
under the widely varying conditions under which the manufacture of chlorine is
carried on in different parts of the world.

Let me express a hope that a hundred years hence the same will be said of the
processes now emerging and the processes still to spring out of the inventor's mind.
Rapid and varied as has been the development of this manufacture,1 cannot sup- -
pose that its progress is near its end, and that Nature has revealed to us all her
secrets as to how to procure chlorine with the least expenditure of trouble and
energy. Ido not believe that industrial chemistry will in future be diverted from
this Section and have to wander to Section A. under the segis of applied electricity.
{ do not believe that the easiest way of effecting chemical changes will ultimately
be found in transforming heat and chemical affinity into electricity, tearing up
chemical compounds by this powerful medium, and then to recombine their con-
stituents in such form as we may require them. I am sure there is plenty of scope
for the manufacturing chemist to solve the problems before him by purely chemi- ~
cal means, of some of which we may as little dream to-day as a few years ago it
could have been imagined that nickel would be extracted from its ores by means
of carbon-monoxide. :

At a meeting of this Association which brings before us an entirely new form
of energy, the Réntgen rays, which have enabled us to see through doors and walls
and to look inside the human body ; which brings before us a new form of matter,
represented by Argon and Helium, which, as their discovevers, Lord Rayleigh and
Professor Ramsay, have now abundantly proved, are certainly elementary bodies,
inasmuch as they cannot be split up further, but are not chemical elements, as they
possess no chemical aflinity and do not enter into combinations—at a meeting at
which such astounding and unexpected secrets of nature are revealed to us, who
would call in doubt that, notwithstanding the immense progress pure and applied
science have made during this century, new and greater and ferthan-cen dll dis-
coveries are still in store for ages to come ?

Brifish Association for fhe Advancement
of Science.

LIVERPOOL 1896

ADDRESS

TO THE

GEOLOGICAL SECTION

BY

J. E. MARR, M.A., F.R.S., Sec. GS.,

PRESIDENT OF THE SECTION,

Tue feelings of one who, being but little versed in the economic applications of
his science, is called upon to address a meeting of the Association held ina large in-
dustrial centre, might, under ordinary circumstances, be of no very pleasant character ;
but I take courage when I remember that those connected with my native county,
in which we are now gathered, have taken prominent part in advancing
branches of our science which are not directly concerned with industrial affairs.
I am reminded, for instance, that one amongst you, himself a busy professional
man, has in his book on ‘The Origin of Mountain Ranges’ given to the world a
theoretical work of the highest value; that, on the opposite side of the county,
those who are responsible for the formation and management of that excellent
educational institution, the Ancoats Museum, have wisely recognised the value of
some knowledge of geology as a means of quickening our appreciation of the
beauties of Nature ; and that one who has done solid service to geology by his
teachings, who has kept before us the relationship of our science to that which is
beautiful—l refer to the distinguished author of ‘Modern Painters’—has chosen
the northern part of the county for his home, and has illustrated his teaching
afresh by reference to the rocks of the lovely district around him. Nor can I help
referring to one who has recently passed away—the late Sir Joseph Prestwich—
the last link between the pioneers of our science and the geologists of the present
day, who, though born in London, was of Lancashire family, and whom we may
surely therefore claim as one of Lancashire’s worthies. With these evidences of
the catholicity of taste on the part of geologists connected with the county, I feel
free to choose my own subject for this address, and, my time being occupied to a
large extent with academic work, I may be pardoned for treating that subject in
academic fashion. As I have paid considerable attention to the branch of the
science which bears the somewhat uncouth designation of stratigraphical geology,
I propose to take the present state of our knowledge of this branch as my theme.
Of the four great divisions of geology, petrology may be claimed as being
largely of German origin, the great impetus to its piney having been given b:
Werner and his teachings. Paleontology may be as justly claimed by the Rieu
nation, Cuvier having been to so great an extent responsible for placing it upon
a scientific basis. Physical geology we may partly regard as our own, the principles
laid down by Hutton and supported by Playfair having received illustration from
a host of British writers, amongst whom may be mentioned Jukes, Ramsay, sud

C

9 REPORT—1896.

the brothers Geikie; but the grand principles of physical geology have been 80
largely illustrated by the magnificent and simple features displayed on the other
side of the Atlantic, that we may well refer to our American brethren as leaders in
this branch of study. The fourth branch, stratigraphical geology, is essentially
British as regards origin, and, as everyone is aware, its scientific principles were
established by William Smith, who was not only the father of English geology,
but of stratigraphical geology in general.

Few will deny that stratigraphical geology is the highest branch of the science,
for, as has been well said, it ‘gathers up the sum of all that is made known by the
other departments of the science, and makes it subservient to the interpretation of
the geological history of the earth.’ The object of the stratigraphical geologist is
to obtain information concerning all physical, climatic, and biological events which
have occurred during each period of the past, and to arrange them in chronological
order, so as to write a connected history of the earth. If all of this information
were at our disposal, we could write a complete earth-history, and the task of the
geologist would be ended. As it is, we have barely crossed the threshold of
discovery, and the ‘imperfection of the geological record,’ like the ‘glorious un-
certainty ’ of our national game, gives geology one of its great charms. Before
passing on to consider more particularly the present state of the subject of our
study, a few remarks upon this imperfection of the geological record may not be
out of place, seeing that the term has been used by so many modern writers, and
its exact signification occasionally misunderstood. The imperfection of the
paleontological record is usually understood by the term when used, and it will be
considered here as an illustration of the incompleteness of our knowledge of earth-
history ; but it must be remembered that the imperfection of the physical record is
equally striking, as will be insisted on more fully in the sequel.

Specially prominent amongst the points upon which we are ignorant stands the
nature of the Precambrian faunas. The extraordinary complexity of the earliest
known Cambrian fauna has long been a matter for surprise, and the recent dis-
coveries in connection with the Olenel/us fauna do not diminish the feeling.’
After commenting upon the varied nature of the earliest known fauna, the late
Professor Huxley, in his Address to the Geological Society in 1862, stated that
‘any admissible hypothesis of progressive modification must be compatible with

rsistence without progression, through indefinite periods. . . . Should such an
leathesis eventually be proved to be true, . . . the conclusion will inevitably
present itself, that the Paleozoic, Mesozoic, and Cainozoic faune and flor, taken
together, bear somewhat the same proportion to the whole series of living beings
which have occupied this globe, as the existing fauna and flora do to them.’
Whether or not this estimate is correct, all geologists will agree that a vast period
of time must have elapsed before the Cambrian period, and yet our ignorance of -
faunas existing prior to the time when the Olenel/us fauna occupied the Cambrian
seas is almost complete, True, many Precambrian fossils haveZbeen described at
various times, but, in the opinion of many competent judges, the organic nature of
each one of these requires confirmation. I need not, however, enlarge upon this
matter, for 1 am glad to say we have amongst us a geologist who will at a later
stage read a paper before this Section upon the subject of Precambrian fossils, and
there is no one better able, owing to his intimate acquaintance with the actual
relics, to present fairly and impartially the arguments which have been¥advanced
in favour of the organic origin of the objects which have been appealed to as
evidences of organisms of Precambrian age than our revered co-worker from
Canada, Sir J. William Dawson. We may look forward with confidence to the
future discovery of many faunas older than those of which we now possess certain

' Dr. C. D. Walcott, in his monograph on ‘The Fauna of the Lower Cambrian or
Olenellus Zone ’ (Washington 1890), records the following great groups as represented
in the Olenellus beds of America :—Spongie, Hydrozoa, Actinozoa, Echinodermata,
Annelida ? (trails, barrows, and tracks), Brachiopoda, Lamellibranchiata, Gasteropoda,
Pteropoda, Crustacea, and Trilobita, Others are known as occurring in beds of the
same age in the Old World.

TRANSACTIONS OF SECTION C. 3

knowledge, but until these are discovered, the paleontological record must be
admitted to be in a remarkably incomplete condition. In the meantime, a study
of the recent advance of our knowledge of early life is significant of the mode in
which still earlier faunas will probably be brought to light, In 1845, Dr. E.
Emmons described a fossil, now known to be an Olenel/us, though at that time the
earliest fauna was supposed to be one containing a much later group of organisms,
and it was not until Nathorst and Brégger established the position of the Olenellus
zone that the existence of a fauna earlier than that of which Paradovides was a
member was admitted ; and, indeed, the Paradovides fauna itself was proved to be
earlier than that containing Olenus, long after these two genera had been made
familiar to palzeontologists, the Swedish paleontologist, Augelin, having referred
the Paradowvides fauna to a period earlier than that of the one with Olenus. It is
quite possible, therefore, that fossils are actually preserved in our museums at the
present moment, which have been extracted from rocks deposited before the period
of formation of the Olene//us beds, though their age has not been determined. The
Olenellus horizon now furnishes us with a datum-line from which we can work
backwards, and it is quite possible that the Neobolus beds of the Salt Range,'
which underlie beds holding O/enel/us, really do contain, as has been maintained, a
fauna of date anterior to the formation of the Olene//us beds; and the same may
be the case with the beds containing the Proto/enus fauna in Canada,’ for this
fauna is very different from any known in the Olenellus beds, or at a higher
horizon, though Mr. G. F. Matthew, to whom geologists owe a great debt for his
admirable descriptions of the early fossils of the Canadian rocks, speaks very
cautiously of the age of the beds containing Protolenus and its associates. Not-
withstanding our ignorance of Precambrian faunas, valuable work has recently
been done in proving the existence of important groups of stratified rocks deposited
previously to the formation of the beds containing the earliest known Cambrian
fossils; I may refer especially to the proofs of the Precambrian age of the
Torridon sandstone of north-west Scotland, lately furnished by the officers of the
Geological Survey, and their discovery that the maximum thickness of these
strata is over 10,000 feet.s Amongst the sediments of this important system,
more than one fauna may be discovered, even if most of the strata were accu-
mulated with rapidity, and all geologists must hope that the officers of the Survey—
who, following Nicol, Lapworth, and others, have done so much to elucidate the
geological structure of the Scottish Highlands—may obtain the legitimate reward
of their labours, and definitely prove the occurrence of rich faunas of Precambrian
age in the rocks of that region.

But, although we may look forward hopefully to the time when we may lessen
the imperfection of the records of early life upon the globe, even the most hopeful
cannot expect that record to be rendered perfect, or that it will make any near
approach to perfection. The posterior segments of the remarkable trilobite
Mesonacis vermontana are of a much more delicate character than the anterior
ones, and the resemblance of the spine on the fifteenth ‘ body-segment’ of this
species to the terminal spine of Olenel/us proper, suggests that in the latter sub-
genus posterior segments of a purely membranous character may have existed,
devoid of hard parts. If this be so, the entire outer covering of the trilobites, at a

eriod not very remote from the end of Precambrian times, may have been mem-

ranous, and the same thing may have occurred with the structures analogous to
the hard parts of organisms of other groups. Indeed, with our present views as
to development, we can scarcely suppose that organisms acquired hard parts at a
very early period of their existence, and fauna after fauna may have occupied the
globe, and disappeared, leaving no trace of its existence, in which case we are not
likely ever to obtain definite knowledge of the characters of our earliest faunas,

' See F. Noetling, ‘On the Cambrian Formation of the Eastern Salt Range.’
Records Geol. Survey India, vol. xxvii. p. 71.

? G. F. Matthew, ‘The Protolenus Fauna.’ Trans. New York Acad. of Science,
1895, vol. xiv. p. 101.

* Sir A. Geikie, ‘Annual Report of the Geological Survey [United Kingdom] . . .
for the year ending December 31, 1893,’ London, 1894.

C2

4 REPORT—1896.

and the biologist must not look to the geologist for direct information concerning
the dawn of life upon the earth.

Proceeding now to a consideration of the faunas of the rocks formed after
Precambrian times, a rough test of the imperfection of the record may be made b
examining the gaps which occur in the vertical distribution of forms of life. If
our knowledge of ancient faunas were very incomplete, we ought to meet with
many cases of recurrence of forms after their apparent disappearance from inter-
yening strata of considerable thickness, and many such cases have actually been
described by that eminent paleontologist, M. Barrande, amongst the Paleozoic
rocks of Bohemia, though even these are gradually being reduced in number owing
to recent discoveries ; indeed, in the case of the marine faunas, marked cases of
recurrence are comparatively rare, and the occurrence of each form is generally
fairly unbroken from its first appearance to its final extinction, thus showing that
the imperfection of the record is by no means so marked as might be supposed.
Freshwater and terrestrial forms naturally furnish a large percentage of cases of
recurrence, owing to the comparative rarity with which deposits containing such
organisms are preserved amongst the strata.

A brief consideration of the main reasons for the present imperfection of our
knowledge of the faunas of rocks formed subsequently to Precambrian times may
be useful, and suggestive of lines along which future work may be carried out.
That detailed work in tracts of country which are yet unexplored, or have been but
imperfectly examined by the geologist, will add largely to our stock of information,
needs only to be mentioned; the probable importance of work of this kind in the
future may be inferred from a consideration of the great increase of our know-
ledge of the Permo-Carboniferous faunas, as the result of recent labours in remote
regions. It is specially desirable that the ancient faunas and floras of tropical re-
gions should be more fully made known, as a study of these will probably throw
considerable light upon the influence of climate upon the geographical distribution
of organisms in past times. The old floras and faunas of Arctic regions are
becoming fairly well known, thanks to the zeal with which the Arctic regions have
been explored. But, confining our attention to the geology of our own country,
much remains to be done even here, and local observers especially have opportuni-
ties of adding largely to our stock of knowledge, a task they have performed so
well in the past. To give examples of the value of such work, our knowledge of
the fauna of the Cambrian rocks of Britain is largely due to the present President
of the Geological Society, ’when resident at St. David’s, whilst the magnificent
fauna of the Wenlock limestone would have been far less perfectly known than
it is, if it were not for the collections of men like the late Colonel Fletcher and
the late Dr. Grindrod. Again, the existence of the rich fauna of the Cambridgé
Greensand would have been unsuspected, had not the bed known by that name
been worked for the phosphatic nodules which it contains.

It is very desirable that large collections of varieties of species should be made,
for in this matter the record is very imperfect. There has been, and, I fear, is still,
a tendency to reject specimens when their characters do not conform with those given
in specific descriptions, and thus much valuable material is lost. Local observers
should be specially careful to search for varieties, which may be very abundant in
places where the conditions were favourable for their production, though rare or
unknown elsewhere. ‘Thus, I find the late Mr. W. Keeping remarking that ‘ it is
Loteworthy that at Upware, and indeed all other places known to me, the species
of Brachiopoda {of the Neocomian beds] maintain much more distinctness and
isolation from one another than at Brickhill.’!_ The latter place appears to be one
where conditions were exceptionally favourable in Neocomian times for the pro-
duction of intermediate forms,

A mere knowledge of varieties is, however, of no great use to the collector
without a general acquaintance with the morphology of the organisms whose
remains he extracts from the earth’s strata, and one who has this can do signal

! W. Keeping, Sedgwick Rssay: The Fossils and Paleontological Affinities of the
Neocomian Deposits of Upware and Brickhill, Cambridge, 1883.

TRANSACTIONS OF SECTION C.

service to the science. It is specially important that local observers should be
willing to devote themselves to the study of particular groups of organisms, and
to collect large suites of specimens of the group they have chosen for study. With
a group like the graptolites, for instance, the specimens which are apparently best
preserved are often of little value from a morphological point of view, and frag-
ments frequently furnish more information than more complete specimens. These
fragments seldom find their way to our museums, and accordingly we may examine
a large suite of graptolites in those museums without finding any examples showing
particular structures of importance, such as the sac-like bodies carried by many of
these creatures. As an illustration of the value of work done by one who has
made a special study of a particular group of organisms, I may refer to the
remarkable success achieved by the late Mr. Norman Glass in developing the
calcareous supports of the brachial processes of Brachiopods. Work of this charac-
ter will greatly reduce the imperfection of the record from the biologists’ point of
view.

The importance of detailed work leads one to comment upon the general
methods of research which have been largely adopted in the ease of the stratified
rocks. The principle that strata are identitiable by their included organisms is the
basis of modern work, as it was of that which was achieved by the father of
English Geology, and the identification of strata in this manner has of recent
years been carried out in very great detail, notwithstanding the attempt on the
part of some well-known writers to show that correlation of strata in great detail
is impossible. The objection to this detailed work is mainly founded upon the
fact that it must take time for an organism or group of organisms to migrate from
one area to another, and therefore it was stated that they cannot have lived con-
temporaneously in two remote areas. But the force of this objection is practically
done away with if it can be shown that the time taken for migration is exceedingly
short as compared with the time of duration of an organism or group of organisms
upon the earth, and this has been shown in the only possible way—namely, by
accumulating a very great amount of evidence as the result of observation. The
eminent writers referred to above, who were not trained geologists, never properly
grasped the vast periods of time which must have elapsed during the occurrence of
the events which it is the geologist’s province to study. An historian would speak
of events which began at noon on a certain day and ended at midnight at the
close of that day as contemporaneous with events which commenced and ended
five minutes later, and this is quite on a par with what the geologist does when
correlating strata. Nevertheless, there are many people who still view the
task of correlating minute subdivisions of stratified systems with one another,
with a certain amount of suspicion, if not with positive antipathy; but the
work must be done for all that. Brilliant generalisations are attractive as
well as valuable, but the steady accumulation of facts is as necessary for the
advancement of the science as it was in the days when the Geological Society
was founded, and its members applied themselves ‘to multiply and record
observations, and patiently to await the result at some future period.’ I have
already suggested a resemblance between geology and cricket, and I may be per-
mitted to point out that just as in the game the free-hitter wins the applause,
though the patient ‘ stone-waller’ often wins the match, so, in the science, the man
apt at brilliant generalisations gains the approval of the general public, but the
patient recorder of apparently insignificant details adds matter of permanent value
to the stores of our knowledge. In the case of stratigraphical geology, if we
were compelled to be content with correlation of systems only, and were unable to
ascertain which of the smaller series and stages were contemporaneous, but could
only speak of these as ‘ homotaxial,’ we should be in much the same position as
the would-be antiquary who was content to consider objects fashioned by the
Romans as contemporaneous with those of medieval times. Under such cireum-
stances geology would indeed be an uncertain science, and we should labour in the
field, knowing that a satisfactory earth-history would never be written. Let us
hope that a brighter future is in store for us, and let me urge my countrymen to
continue to study the minute subdivisions of the strata, lest they be left behina by

6 REPORT—1896.

the geologists of other countries, to whom the necessity for this kind of study is
apparent, and who are carrying it on with great success.

The value of detailed work on the part of the stratigraphical geologist is best
grasped if we consider the recent advance that has been made in our science owing
to the more or less exhaustive survey of the strata of various areas, and the appli-
cation of the results obtained to the elucidation of earth’s history. A review of
this nature will enable us not only to see what has been done, but also to detect
lines of inquiry which it will be useful to pursue in the future; but it is obvious
that the subject is so wide that little more can be attempted than to touch lightly
upon some of the more prominent questions. A work might well be written
treating of the matters which I propose to notice. We have all read our ‘ Prin-
ciples of Geology,’ or ‘The Modern Changes of the Earth and its Inhabitants
considered as illustrative of Geology,’ to quote the alternative title; some day we
may have a book written about the ancient changes of the earth and its inhabitants
considered as illustrative of geography.

Commencing with a glance at the light thrown on inorganic changes by a
detailed examination of the strata, I may briefly allude to advances which have
recently been made in the study of denudation. The minor faults, which can only
be detected when the small subdivisions of rock-groups are followed out carefully
on the ground, have been shown to be of great importance in defining the direction
in which the agents of denudation have operated, as demonstrated by Professor
W. C. Brégger, for instance, im the case of the Christiania Fjord ;' and I have
recently endeavoured to prove that certain valleys in the English Lake District
have been determined by shattered belts of country, the existence of which is
shown by following thin bands of strata along their outcrop. The importance of
the study of the strata in connection with the genesis and subsequent changes of
river-systems is admirably brought out in Professor W. M. Davis's paper on ‘The
Development of certain English Rivers,? a paper which should be read by all
physical geologists; it is, indeed, a starting-point for kindred work which remains
especially for local observers to accomplish. Study of this kind not only adds to
our knowledge of the work of geological agencies, but helps to diminish the im- -
perfection of the record, for the nature of river-systems, when rightly understood,
enables us to detect the former presence of deposits over areas from which they
have long since been removed by denudation.

An intimate acquaintance with the lithological characters of the strata of a
district affords valuable information in connection with the subject of glacial
denudation. The direction of glacial transport over the British Isles has been
largely inferred from a study of the distribution of boulders of igneous rock, whilst
those of sedimentary rock have been less carefully observed. The importance of
the latter is well shown by the work which has been done in Northern Europe in ~
tracing the Scandinavian boulders to their sources, a task which could not have
been performed successfully if the Scandinavian strata had not been studied in
great detail® I shall presently have more to say with regard to work connected
with the lithological characters of the sediments. Whilst mentioning glacial
denudation, let me allude to a piece of work which should be done in great detail,
though it is not, strictly speaking, connected with stratigraphy, namely, the
mapping of the rocks around asserted ‘rock-basins.’ I can find no actual proof
of the occurrence of such basins in Britain, and it is very desirable that the solid
rocks and the drift should be carefully inserted on large-scale maps, not only all
around the shores of several Jakes, but also between the lakes and tbe sea, in order
to ascertain whether the lakes are really held in rock-basins. Until this work

' W.C Brogger, Nyt. Wag. for Naturvidensk. vol. xxx. (1886), p. 79.

* W. M. Davis, Geograph. Journ. vol. v. (1895) p. 127.

* It is desirable that the boulders of sedimentary rock imbedded in the drifts of
East Anglia should be carefully examined and fossils collected from them. The
calcareous strata associated with the Alum Shales of Scandinavia and the strata of
the Orthoceras-Limestone of that region may be expected to be represented amongst
the boulders.

TRANSACTIONS OF SECTION C. 7

is done, however probable the occurrence of rock-basins in Britain may be con-
sidered to be, their actual existence cannot be accepted as proved.

When referring to the subject of denudation, mention was made a moment ago
of the study of the lithological character of the sediments. Admirable work in
this direction was carried out years ago by one who may be said to have largely
changed the direction of advance of geology in this country owing to his researches
*On the Microscopical Structure of Orystals, indicating the Origin of Minerals and
Rocks.’ I refer, of course, to Dr. H.C. Sorby. But since our attention has been
so largely directed to petrology, the study of the igneous and metamorphic rocks
has been most zealously pursued, whilst that of the sediments has been singularly
little heeded, with few exceptions, prominent amongst which is the work of
Mr. Maynard Hutchings, the results of which have been recently published in the
‘Geological Magazine,’ though we must all hope that the details which have
hitherto been supplied to us, valuable as they are, are only a foretaste of what is
to follow from the pen of this able observer. Descriptions of the lithological
changes which occur in a vertical series of sediments, as well as of those which are
observed when any particular band is traced laterally, will no doubt throw light
upon a number of interesting questions.

Careful work amongst the ancient sediments, especially those which are of
organic origin, has strikingly illustrated the general identity of characters, and
therefore of methods of formation, of deposits laid down on the sea-floors of past
times and those which are at present in course of construction. Globigerine-oozes
have been detected at various horizons and in many countries. Professor H,
Alleyne Nicholson ' has described a pteropod-ooze of Devonian age in the Hamilton
Limestone of Canada, which is largely composed of the tests of Styliola; and to
Dr. G. J. Hinde we owe the discovery of a large number of radiolarian cherts of
Paleozoic and Neozoic ages in various parts of the globe. The extreme thinness
of many argillaceous deposits, which are represented elsewhere by hundreds of feet
of strata, suggests that some of them, at any rate, may be analogous to the deep-
sea clays of modern oceans, though in the case of deposits of this nature we must
depend to a large extent upon negative evidence. The uniformity of character of
thin marine deposits over wide areas is in itself evidence of their formation at
some distance from the land; but although the proofs of origin of ancient sedi-
ments far from coast-lines may be looked upon as permanently established, the
evidence for their deposition at great depths below the ocean's surface might be
advantageously increased in the case of many of them. The fairly modern sedi-
ments, containing genera which are still in existence, are more likely to furnish
satisfactory proofs of a deep-sea origin than are more ancient deposits. Thus the
existence of Archeopneustes and Cystechinus in the oceanic series of Barbadoes, as
described by Dr. J. G. Gregory, furnishes strong proofs of the deep-sea character
of the deposits, whilst the only actual argument in favour of the deep-sea character
of certain Paleozoic sediments has been put forward by Professor Suess, who notes
the similarity of certain structures of creatures in ancient rocks to those possessed
by modern deep-sea crustacea, especially the co-existence of trilobites which are
blind with those which have enormously developed eyes.

A question which has been very prominently brought to the fore in recent
years is that of the mode of formation of certain coral-reefs. The theory of
Charles Darwin, lately so widely accepted as an explanation of the mode of
formation of barrier-reefs and atolls, has been, as is well known, criticised by
Dr. Murray, with the result that a large number of valuable observations have
been recently made on modern reefs, especially by biologists, as a contribution to
the study of reef formation. Nor have geologists been inactive. Dr. E. Mojsisovics
and Professor Dupont, to mention two prominent observers, have described knoll-
like masses of limestone more or less analogous, as regards structure, to modern
coral-reefs, They consider that these have been formed by corals, and indeed
Dupont maintains that the atoll-shape is still recognisable in ancient Devonian

’ Nicholson and Lydekker, Manual of Paleontology, chap. ii.

8g REPORT—1896.

coral-reefs in Belgium.' I would observe that all cases of ‘ knoll-reefs’ of this
character have been described in districts which furnish proofs of having been
subjected to considerable orogenic disturbance, subsequent to the formation of the
rocks composing the knoll-shaped masses, whilst in areas which have not been
affected by violent earth-foldings, the reef-building corals, so far as 1 have been
able to ascertain, give rise to sheet-like masses, such as should be produced accord-
ing to Dr. Murray’s theory. I would mention especially the reets of the Corallian
Rocks of England, and also some admirable examples seen amongst the Carbo-
niferous Limestone strata of the great western escarpment of the Pennine Chain
which faces the Eden Valley in the neighbourhood of Melmerby in Cumberland.
Considering the number of dissected coral-reefs which exist amongst the strata of
the earth’s crust, and the striking way in which their structure is often displayed,
it is rather remarkable that comparatively little attention has been paid to them
by geologists in general, when the subject has been so prominently brought before
the scientific world, for we must surely admit that we are much more likely to gain
important information, shedding light upon the methods of reef-formation, by a
study of such dissected reefs, than by making a few bore-holes on some special
coral island. I would specially reeommend geologists to make a detailed study of
the British coral-reefs of Silurian, Devonian, Carboniferous, and Jurassic ages.

Turning now to organic deposits of vegetable origin, we must, as the result of
detailed work, be prepared to admit the inapplicability of any one theory of the
formation of coal seams. The ‘ growth-in-place’ theory may be considered fairly
well established for some coals, such as the spore-coals, whilst the ‘drift’ theory
furnishes an equally satisfactory explanation of the formation of cannel-coal.
It is now clear that the application of the general term coa/ to a number of
materials of diverse nature, and probably of diverse origin, was largely responsible
for the dragging-out of a controversy, in which the champions of either side
endeavoured to explain the origin of all coal in one particular way.

The stratigraphical geologist, attempting to restore the physical geography of
former periods, naturally pays much attention to the positions of ancient coast-
lines ; indeed, all teachers find it impossible to give an intelligible account of the _
stratified rocks without some reference to the distribution of land and sea at the
ume of their formation. The general position of land-masses at various times has
been ascertained in several parts of the world, but much more information must be
gathered together before our restorations of ancient sea-margins approximate to
the truth. The Carboniferous rocks of Britain have been specially studied with
reference to the distribution of land and water during the period of their accumu-
lation, and yet we find that owing to the erroneous identitication of certain rocks
of Devonshire as grits or sandstones, which Dr. Hinde has shown to be radiolarian
cherts, land was supposed to lie at no great distance south of this region in Lower -
Carboniferous times, whereas the probabilities are in favour of the existence of an
open ocean at a considerable distance from any land in that direction. This case
furnishes us with an excellent warning against generalisation upon insuflicient
data.

As a result of detailed study of the strata, the effects of earth-moyements
have been largely made known to us, especially of those comparatively
local disturbances spoken of as orogenic which are mainly connected with
mountain-building, whilst information concerning the more widely spread
epeirogenic movements is also furnished by a study of the stratified rocks, The
structure of the Alps, of the North-West Highlands of Scotland, and of the
uplifted tracts ot North America is now familiar to geologists, whilst the study
of comparatively recent sediments has proved the existence of widespread and
extensive movements in times which are geologically modern; for instance, the
deep-water deposits of late Tertiary age found in the West Indies indicate
the occurrence of considerable uplift in that region. But a great amount of

' Similar knoll-like masses have been described in this country by Mr. R. H.
Tiddeman, as occurring in the Craven district of Yorkshire, but he does not attribute
their formation to coral-growth to any great extent,

TRANSACTIONS OF SECTION C. 9

work yet remains to be done in this connection, especially concerning horizontal
distortion of masses of the earth’s crust, owing to more rapid horizontal advance
of one portion than of another, during periods of movement. Not until we gather
together a large amount of information derived from actual inspection of the rocks
shall we be able to frame satisfactory theories of earth-movement, and in
the meantime we are largely dependent upon the speculations of the physicist,
often founded upon very imperfect data, on which is built an imposing super-
structure of mathematical reasoning. We have been told that our continents and
ocean-basins have been to a great extent permanent as regards position through
long geological ages ; we now reply by pointing to deep-sea sediments of nearly
all geological periods, which have been uplifted from the ocean-abysses to form
portions of our continents; and as the result of study of the distribution of fossil
organisms, we can point almost as confidently to the sites of old continents now
sunk down into the ocean depths. It seems clear that our knowledge of the causes
of earth-movements is still in its infancy, and that we must be content to wait
awhile, until we have further information at our disposal.

Recent work has proved the intimate connection betwixt earth-movement and
the emission and intrusion of igneous rocks, and the study of igneous rocks has
advanced beyond the petrographical stage; the rocks are now made to contribute
their share towards the history of different geological periods. The part which
voleanic action has played in the actual formation of the earth’s crust is well
exemplified in Sir Archibald Geikie’s Presidential Addresses to the Geological
Society, wherein he treats of the former volcanic history of the British Isles.'_ The
way in which extruded material contributes to the formation of sedimentary
masses has, perhaps, not been fully grasped by many writers, who frequently seem
to assume that deposition is a measure of denudation, and vice versd, whereas
deposition is only a measure of denudation, and of the material which has been
ejected in a fragmental condition from the earth’s interior, which in some places
forms a very considerable percentage of the total amount of sediment.

The intruded rocks also throw much light on past earth-history, and I cannot
give a better illustration of the valuable information which they may furnish to
the stratigraphical geologist, when rightly studied, than by referring to the
excellent and suggestive work by my colleague, Mr. Alfred Harker, on the Bala
Voleanic Rocks of Carnarvonshire.’

Perhaps the most striking instance of the effect which detailed stratigraphical
work has produced on geological thought is supplied by the study of the erystal-
line schists. Our knowledge of the great bulk of the rocks which enter into the
formation of a schistose complex is not very great, but the mode of production of
many of them is now well known, and the crude speculations of some of the early
geologists are now making way for theories founded on careful and minute obser-
vations in the field as well as in the laboratory. Recent work amongst the crystal-
line schists shows, furthermore, how careful we should be not to assume that
because we have got at the truth, we have therefore ascertained the whole truth.
We all remember how potent a factor dynamic metamorphism was supposed to be,
owing to discoveries made in the greatly disturbed rocks of Scotland and Switzer-
land; and the action of heat was almost ignored by some writers, except as a
minor factor, in the production of metamorphic change. The latest studies amongst
the foliated rocks tend to show that heat does play a most important part in the
manufacture ot schists. The detailed work of Mr. George Barrow, in North-East
Forfarshire,* has already thrown a flood of light upon the origin of certain schists,
and their connection with igneous rocks, and geologists will look forward with
eagerness to further studies of the puzzling Highland rocks by this keen observer.

The subject of former climatic conditions is one in which the geologist has
very largely depended upon followers of other branches of science for light, and
yet it is one peculiarly within the domain of the stratigraphical geologist; and

' Sir A. Geikie, Quart. Journ. Geol. Soe, vols. xlvii. and xlviii.
* Alf. Harker, Sedgwick Essay for 1888 (Camb. Univ. Press, 1889).
* G. Barrow, Quart. Journ. Geol. Soc. vol. xlix. (1893), p. 330.

10 REPORT—1896.

information which has already been furnished concerning former élimatic eondi-
tions, as the result of careful study of the strata, is cad tes only an earnest of
what is to follow when the specialist in climatology pays attention to the records
of the rocks, and avoids the theories elaborated in the student’s sanctum. The
recognition of an Ice Age in Pleistocene times at once proved the fallacy of the
supposition that there has been a gradual fall in temperature throughout geological
ages without any subsequent rise, and accordingly most theories which have been
put forward to account for former climatic change have been advanced with special
reference to the Glacial period or periods, although there are many other interest-
ing matters connected with climate with which the geologist has to deal. Never-
theless, the occurrence of glacial periods is a matter of very great interest, and
one which has deservedly received much attention, though the extremely plausible
hypothesis of Croll, and the clear manner in which it has been presented to general
veaders, tended to throw other views into the shade, until quite recently, when
this hypothesis has been controverted from the point of view of the physicist. In
the meantime considerable advance has been made in our actual knowledge, and
this year, probably for the first time, and as the result of the masterly réswmé of
Professor Edgworth David,' the bulk of British geologists are prepared to admit
that there has been more than one glacial period, and that the evidence of glacial
conditions in the southern hemisphere in Permo-Carboniferous times is esta-
blished. Croll’s hypothesis of course requires the recurrence of glacial periods, but
leaving out of account arguments not of a geological character, which have been
advanced against this hypothesis, the objection raised by Messrs. Gray and
Kendall,? that in the case of the Pleistocene Ice Age ‘the cold conditions
came on with extreme slowness, the refrigerations being progressive from the
Jocene period to the climax,’ seems to me to be a fatal one. At the same time,
rather than asking with the above writers ‘the aid of astronomers and physicists
in the solution of’ this problem, I would direct the attention of stratigraphical
geologists to it, believing that, by steady accumulation of facts, they are more
likely than anyone else to furnish the true clue to the solution of the glacial
roblem.

: I have elsewhere called attention to marked changes in the faunas of the
sedimentary rocks when passing from lower to higher levels, without the evidence
of any apparent physical break, or any apparent change in the physical conditions,
so far as can be judged from the lithological characters of the strata, and have
suggested that such sudden faunistic variations may be due to climate. I refer to
the matter as one which nay well occupy the attention of local observers.

One of the most interesting points connected with climatic conditions is
that of the former general lateral distribution of organisms, and its dependence
upon the distribution of climatic zones. The well-known work of the late -
Dr. Neumayr® has, in the opinion of many geologists, established the existence of
climatic zones whose boundaries ran practically parallel with the equator in
Jurassic and Cretaceous times, and the possible existence of similar climatic zones
in Paleozoic times has been elsewhere suggested; but it is very desirable that
much more work should be done upon this subject, and it can only be carried out
by paying close attention to the vertical and lateral distribution of organisms in
the stratified rocks.

So far we have chiefly considered the importance of stratigraphical geology
in connection with the inorganic side of nature. We now come to the bearing of
detailed stratigraphical work upon questions concerning the life of the globe, and
here the evidence furnished by the geologist particularly appeals to the general
educated public as well as to students of other sciences.

17T. W. E. David, ‘ Evidences of Glacial Action in Australia in Permo-
Carboniferous Time,’ Quart. Journ. Geol. Soe. vol. lii. p. 289.

2 J. W. Gray, and P. F. Kendall, ‘The Cause of an Ice Age, Brit. Assoc. Rep.
(1892), p. 708.

* M. Neumayr, ‘ Ueber klimatische Zonen wihrend der Jura- und Kreidezeit,’
Denkschr. der math.-naturrissen. Classe der kh. k. Akad. der Wissenschaften, vol. xlvii.
Vienna, 1883,

TRANSACTIONS OF SECTION C. 11

Attention has just been directed to the probable importance of former
climatic changes in determining the distribution of organisms, but the whole
subject of the geographical distribution of organisms during former geological
ester though it has already received a considerable amount of attention, will

oubtless have much further light thrown upon it as the result of careful observations
carried out amongst the stratitied rocks.

So long ago as 1853, Pictet laid it down as a paleontological law that ‘the
geographical distribution of species found in the strata was more extended than
the range of species of existing faunas.’ One would naturally expect that at a
time when the diversity of animal organisation was not so great as it now is,
the species, having fewer enemies with which to cope, and on the whole not too
complex organisations to be affected by outward circumstances, would spread
further laterally than they now du; but as we know that in earliest Cambrian
times the diversity of organisation was very considerable, it is doubtful whether
any appreciable difference would be exerted upon lateral distribution then and
now, owing to this cause. At the time at which Pictet wrote, the rich fauna of
the deeper parts of the oceans, with its many widely distributed forms of life,
was unknown, and the range in space of early organisms must have then struck
everyone who thought upon the subject as being greater than that of the shallow-
water organisms of existing seas, which were alone known. It is by no means
clear, however, with our present knowledge, that Pictet’s supposed law holds
good, and it will require a considerable amount of work before it can be
shown to be even apparently true. Our lists of the fossils of different
areas are not sufficiently complete to allow us to generalise with safety, but
a comparison of the faunas of Australia and Britain indicates a larger
percentage of forms common to the two areas, as we examine higher groups of
the geological column. If this indication be fully borne out by further work, it
will not prove the actual truth of the law, for the apparent wider distribution of
ancient forms of life might be due to the greater probability of elevation of
ancient deep-sea sediments than of more modern ones which have not been sub-
jected to so many elevatory movements. Still, if the law be apparently true, it is
a matter of some importance to geologists; and I have touched upon the matter
here in order once again to emphasise the possibility of correlating comparatively
small thicknesses of strata in distant regions by their included organisms.

Mention of Pictet’s laws, one of which states that fossil animals were con-
structed upon the same plan as existing ones, leads me to remark upon the
frequent assumption that certain fossils are closely related to living groups, when
the resemblances between the hard parts of the living and extinct forms are only
of the most general character. There is a natural tendency to compare a fossil
with its nearest living ally, but the comparison has probably been often pushed
too far, with the result that biologists have frequently been led to look for the
ancestors of one living group exclusively amongst forms of life which are closely
related to those of another living group. The result of detailed work is to bring
out more and more prominently the very important differences between some
ancient forms and ary living creature, and to throw doubts on certain compari-
sons; thus I find several of the well-known fossils of the Old Red Sandstone,
formerly referred without hesitation to the fishes, are now doubtfully placed in
that class.

The importance of detailed observation in the field is becoming every day more
apparent, and the specialist who remains in his museum examining the collections
amassed by the labours of others, and never notes the mode of occurrence of
fossils in the strata, will perhaps soon be extinct, himself an illustration of the
principle of the survival of the fittest. In the first place, such a worker can
never grasp the true significance of the changes wrought on fossil relics after they
have become entombed in the strata, especially amongst those rocks which have
been subjected to profound earth-movements; and it is to be feared that many
“species ‘are still retained in our fossil lists, whose supposed specific characters
are due to distortion by pressure. But a point of greater importance is, that one
who confines his attention to museums, cannot, unless the information supplied to

12 REPORT—1896.

him be very full, distinguish the differences between fossils which are variations
from a contemporaneous dominant form, such as ‘sports, and those which have
been termed ‘ mutations,’ which existed at a later period than the forms which
they resemble. The value of the latter, to those who are attempting to work out
phylogenies is obvious, and their nature can only be determined as the result of
very laborious and accurate field-work ; but such labour in such a cause is well
worth performing, ‘The student of phylogeny has had sufficient warning of the
dangers which beset his path, from an inspection of the various phylogenetic trees,
constructed mainly after study of existing beings only, so

‘. . . like the borealis race,
That flit ere you can point their place,’

but recent researches amongst various groups of fossil organisms have further
illustrated the danger of theorising upon insufficient data, especially sugyestive
being the discovery of closely similar forms which were formerly considered to be
much more nearly related than now proves to be the case; thus Dr. Mojsisovies*
tas shown that Ammonites once referred to the same species are specifically dis-
tinct, though their hard parts have acquired similar structures, sometimes con-
temporaneously, sometimes at different times, and Mr. 8. S. Buckman ? has observed
the same thing, which he speaks of as ‘ heterogenetic homceomorphy’ in the case
of certain brachiopods, whilst Prof. H. A. Nicholson and 1 * have given reasons for
supposing that such heterogenetic homceomorphy, in the case ot the graptolites,
has sometimes caused the inclusion in one genus of forms which haye arisen from
two distinet genera. As the result of careful work, dangers of the nature here
suggested will be avoided, and our chances of indicating lines of descent correctly
will be much increased. It must be remembered that however plausible the lines
of descent indicated by students of recent forms may be, the actual links in the
chains can only be discovered by examination of the rocks, and it is greatly to be
desired that more of our geologists, who have had a thorough training in the field,
should receive in addition one as thorough in the zoological laboratory. Shall I
be forgiven if I venture on the opinion that a certain suspicion which some of my
zoological fellow countrymen have of geological methods, is due to their compara-
tive ignorance of paleontology, and that it is as important for them to obtain
some knowledge of the principles of geology as it is for the stratigraphical
paleontologist to study the soft parts of creatures whose relatives he finds in the
stratified rocks ?

The main lines along which the organisms of some of the larger groups have
been developed, have already been indicated by several paleontologists, and
detailed es has been carried out in several cases. As examples, let me allude

to the trilobites, of which a satisfactory natural classification was outlined by the —

great Barrande in those volumes of his monumental work which deal with the
fossils of this order, whilst further indication of their natural inter-relationships
has been furnished by Messrs. C. D. Walcott, G. F. Matthew, and others; to the
graptolites, whose relationships have been largely worked out by Professor C.
Lapworth, facile princeps amongst students of the Graptolitoidea, to whom we
look for a full account of the phylogeny of the group; to the brachiopods, which
have been so ably treated by Dr. C, li. Beecher,* largely from a study of recent
forms, but also after careful study of those preserved in the fossil state ; and to the
echinids and lamellibranchs, whose history is being extensively elucidated by
Dr. R. T. Jackson,® by methods somewhat similar to those pursued by Dr. Beecher.

' E. Mojsisovics, Abhandl. der kh. k. geol. Reichsanst. vol. vi. (1893).

? 8.5. Buckman, Quart. Journ. Geol. Soc. vol. li. (1895), p. 456.

* H. A. Nicholson, and J. E Marr. Geol. Mag. Dec. 4, vol. ii. (1895), p. 531.

' C. E. Beecher, ‘ Development of the Brachiopoda, Amer. Journ. Sci., Ser. iii.,
vol. xli. (1891) p. 343, and vol. xliv. (1892) p. 133.

* R. T. Jackson, ‘ Phylogeny of the Pelecypoda,’ Mem. Boston Soc. Nat. Hist.,
vol. iv. (1890) p. 277; and ‘Studies of Palwechinoidea,’ Bull. Geol. Soc. Amer. vol.
vii. (1896) p. 171.

e

TRANSACTIONS OF SECTION C. 13

I might give other instances,! but have chosen some striking ones, four of
whic ‘a aaa illustrate the great advances which are being made in the study
of the paleontology of the invertebrates by our American brethren.

I have occupied the main part of my address with reasons for the need of con-
ducting stratigraphical work with minute accuracy. Many of you may suppose
that the necessity for working in this way is so obvious that it isa work of
Supererogation to insist upon it at great length; but experience has taught me
that many geologists consider that close attention to details is apt to deter
workers from arriving at important generalisations, in the present state of our
science, A review of the past history of the science shows that William
Smith, and those who followed after him, obtained their most important
results by steady application to details, and subsequent generalisation, whilst
the work of those who theorise on insufficient data is apt to be of little
avail, though often demanding attention on account of its very daring, and
because of the power of some writers to place erroneous views in an attractive
light, just as

... the sun can fling
Colours as bright on exhalations bred
By weedy pool or pestilential swamp,
As on the rivulet, sparkling where it runs,
Or the pellucid lake.’

Nor is there any reason to suppose that it will be otherwise in the future, and I
am not one of those who consider that the brilliant discoveries were the exclusive
reward of the pioneers in our science, and that labourers of the present day must
be contented with the gleanings of their harvest; on the contrary, the discoveries
which await the geologist will probably be as striking as are those which he has
made in the past. The onward march of science is a rhythmic movement, with
now a period of steady labour, anon a more rapid advance in our knowledge. It
would perhaps be going too far to say that, so far as our science is concerned, we
are living in a period rather of the former than of the latter character, though no
great geological discovery has recently affected human thought in the way in
which it was affected by the proofs of the antiquity of man, and by the publication
of ‘The Origin of Species.’ If, however, we are to some extent gathering materials,
rather than drawing far-reaching conclusions from them, I believe this is largely
due to the great expansion which our science has undergone in recent years. It
has been said that geology is ‘not so much one science, as the application of all
the physical sciences to the examination and description of the structure of the
earth, the investigation of the agencies concerned in the production of that strue-
ture, and the history of their action ;’ and the application of other sciences to the
elucidation of the history of our globe has been so greatly extended of recent years,
that we are apt to lose sight of the fact that geology is in itself a science, and that
it is the special province of the geologist to get his facts at first hand from exami-
nation of the earth. The spectroscope and the telescope tell the geologist much ;
but his proper instrument is the hammer, and the motto of every geologist should
be that which has been adopted for the Geological Congress, ‘ Mente et maileo.’
At the risk of being compared to a child playing with edged tools, I cannot
help referring to the bearing of modern stratigraphical research on the suggested
replacement of a school of uniformitarianism by one of evolution. The distin-
guished advocate of Evolutionism, who addressed the Geological Society in 1869
upon the modern schools of geological thought, spoke of the school of evolution as
though it were midway between those of uniformitarianism and catastrophism, as

' Hg. The following papers treating of the Cephalopoda :—A. Hyatt, ‘ Genesis
of the Arietids,’ Smithsonian Contributions, vol. xxvi. (1889); M. Neumayr, Jura-
Studien LI, ‘ Ueber Phylloceraten,’ Jahrb. der kh. k. Geol. Reichsanst. vol. xxi, (1871),
p- 297; L. Wiirtenberger, ‘Studien iiber die Stammesgeschichte der Ammoniten,’
Leipzig, 1880; S.S. Buckman, ‘A Monograph of the Inferior Oolite Ammonites of
the British Islands, 1887—( Monogr. Palwontographical Soc.)

14 REPORT—1896.

indeed it is logically, though, considering the tenets of the upholders of catastro-
phism, as opposed to those of uniformitarianism, at the time of that address, there
is no doubt that evolutionism was rather a modification of the uniformitarianism
of the period than intermediate between it and catastrophism, which was then
practically extinct, at any rate in Britain. Oue of my predecessors in this chair,
speaking upon this subject, says that ‘the good old British ship “ Uniformity,”
built by Hutton and refitted by Lyell, has won so many glorious victories in the
past, and appears still to be in such excellent fighting trim, that I see no reason
why she should haul down her colours, either to “ catastrophe ” or “evolution.”’
It may be so; but I doubt the expediency of nailing those colours to the mast.
That Lyell, in his great work, proved that the agents now in operation, working
with the same activity as that which they exhibit at the present day, might pro-
duce the phenomena exhibited by the stratified rocks, seems to be generally
admitted, but that is not the same thing as proving that they did so produce them,
Such proof can only be acquired by that detailed examination of the strata which
I have advocated in this address, and at the time that the last edition of the
‘ Principles’ appeared, our knowledge of the strata was far less complete than it
has subsequently become. It appears to me that we should keep our eyes open to
the possibility of many phenomena presented by rocks, even newer than the
Archean rocks, haying been produced under different conditions from those now
prevalent. The depths and salinity of the oceans, the heights and extent of con-
tinents, the conditions of voleanic action, and many other things may have been
markedly different from what they are at present, and it is surely unphilosophical to
assume conditions to have been generally similar to those of the present day, on
the slender data at our disposal. Lastly, uniformitarianism, in its strictest sense,
is opposed to rhythmic recurrence of events. ‘Rhythm is the rule with nature;
she abhors uniformity more than she does a vacuum,’ wrote Professor Tyndall,
many years ago, and the remark is worth noting by geologists Why have we no
undoubted signs of glacial epochs amongst the strata from early Cambrian times to
the Great [ee Period,except in Permo-Carboniferous times? Is there not an apparent
if not a real absence of manifestation of volcanic activity over wide areas of the
earth in Mesozoic times? Were not Devonian, Permo-Triassic, and Miocene times
periods of mountain-building over exceptionally wide areas, whilst the intervening
periods were rather marked by quiet depression and sedimentation? A study of
the evidence available in connection with questions like these suggests rhythmic
recurrence. Without any desire to advocate hasty departure from our present
methods of research, I think it should be clearly recognised that evolution may
have been an important factor in changing the conditions even of those times of
which the geologist has more direct knowledge. In this, as in many other ques-
tions, it is best to preserve an open mind ; indeed, I think that geologists will do well
to rest satisfied without an explanation to many problems, amongst them the one
just referred to; and that working hypotheses, though useful, are better retained in
the manuscript notebooks of the workers than published in the ‘lransactious of
Learned Societies, whence they filter out into popular works, to the great delight
of a sceptical public should they happen to be overthrown.

May I trespass upon your patience for one moment longer? As a teacher
of geology, with many years’ experience in ana out of a large University, I have
come to the conclusion that geology is becoming more generally recognised as a
valuable instrument of education. The memory, the reasoning faculties, and the

owers of observation are alike quickened. The work in the open air, which is
inseparable from a right understanding of the science, keeps the body in healthy
condition. But over and above these benefits, the communing with nature, often
in her most impressive moods, and the insignificance of events in a man’s lifetime,
as compared with the ceaseless changes through the long sons which have gone
before, so influence man’s moral nature, that they drive out his meaner thoughts
and make him ‘liye in charity with all men.’

Brifish Associafion for fhe Advancement of
Science.

LIVERPOOL, 1896.

ADDRESS

TO THE

ZOOLOGICAL SECTION

BY

Proressor E. B. POULTON, M.A., F.RS., F.LS.,

PRESIDENT OF THE SECTION.

A very brief study of the proceedings of this Section in byegone years will show
that Presidents have exercised a very wide choice in the selection of subjects. At
the last Meeting of the Association in this city in 1870 the Biological Section had as
its President the late Professor Rolleston, a man whose remarkable personality
made a deep impression upon all who came under his influence, as | have the
strongest reason for remembering, inasmuch as he was my first teacher in zoology,
and I attended his lectures when but little over seventeen. His address was most
characteristic, glancing over a great variety of subjects, literary as well as scientific,
and abounding in quotations from several languages, living and dead. <A very
different style of address was that delivered by the distinguished zoologist who
presided over the Meeting. Professor Huxley took as his subject ‘The History of
the Rise and Progress of a Single Biological Doctrine.’

Of these two types I selected the latter as my example, and especially desired
to attempt the discussion, however inadequate, of some difficulty which confronts
the zoologist at the very outset, when he begins to reason from the facts around
him—a difficulty which is equally obvious and of equal moment to the highly-
trained investigator and the man who is keenly interested in the results obtained
by others, but cannot himself lay claim to the position and authority of a skilled
observer—to the naturalist and to one who follows some other branch of know-
ledge, but is interested in the progress of a sister science.

wo such difficulties were alluded to by Lord Salisbury in his interesting presi-
dential address to the British Association at Oxford in 1894, when he spoke of
‘two of the strongest objections to the Darwinian explanation’ of evolution—viz.
the theory of natural selection—as appearing ‘ still to retain all their force.’ The
first of these objections was the insufficiency of the time during which the earth
has been in a habitable state, as calculated by Lord Kelvin and Professor Tait,
100 million years being conceded by the former, but only 10 million by the latter.
Lord Salisbury quite rightly stated that for the evolution of the organic world as
we know it by the slow process of natural selection at least many hundred
million years are required ; whereas, ‘if the mathematicians are right, the biologists
cannot have what they demand. . . . The jelly-fish would have been dissipated in
steam long before he had had a chance of displaying the advantageous variation
which was to make him the ancestor of the luuman race.’

The second objection was that ‘we cannot demonstrate the process of natural
selection in detail; we cannot even, with more or less ease, imagine it.’ “In
natural selection who is to supply the breeder's place?’ ‘There would be nothing _

D

2 REPORT—1896

but mere chance to secure that the advantageously varied bridegroom at one end
of the wood should meet the bride, who by a happy contingency had been advan-
tageously varied in the same direction at the same time at the other end of the
wood. It would be a mere chance if they ever knew of each other's existence—a
still more unlikely chance that they should resist on both sides all temptations to
a less advantageous alliance. But unless they did so the new breed would never
even begin, let alone the question of its perpetuation after it had begun.’

Professor Huxley, in seconding the vote of thanks to the President, said that
he could imagine that certain parts of the address mizht raise a very good dis-
cussion in one of the Sections, and I have little doubt that he referred to these
criticisms and to this Section. When I had to face the duty of preparing this
address, I could find no subjects better than those provided by Lord Salisbury.

At first the second objection seemed to offer the more attractive subject. It
was clear that the theory of natural selection as held by Darwin was misconceived
by the speaker, and that the criticism was ill-aimed. Darwin and Wallace, from the
very first, considered that the minute differences which separate individuals were
of far more importance than the large single variations which occasionally arise—
Lord Salisbury’s advantageously varied bride and bridegroom at opposite ends of the
wood. In facet, after Fleeming Jenkins’s criticisms in the ‘ North British Review’
for June 1867, Darwin abandoned these large single variations altogether. Thus
he wrote in a letter to Wallace (February 2, 1869): ‘I always thought individual
differences more important ; but I was blind, and thought single variations might
be preserved much oftener than I now see is possible or probable. I mentioned
this in my former note merely because I believed that you had come to a similar
conclusion, and I like much to be in accord with you.’! Hence we may infer that
the other great discoverer of natural selection had come to the same conclusion at
an even earlier date. But this fact removes the whole point from the criticism
I have just quoted. According to the Darwin-Wallace theory of natural selection,
individuals sufficiently advantageously varied to become the material for a fresh
advance when an advance became necessary, and at other times sufficient to main-
tain the ground previously gained—such individuals existed not only at the
opposite ends of the wood, but were common enough in every colony within its ~
confines. The mere fact that an individual had been able to reach the con-
dition of a possible bride or bridegroom would count for much, Few will dispute
that such individuals ‘have already successfully run the gauntlet of by far the
greatest dangers which beset the higher animals [and, it may be added, the lower
animals also |—the dangers of youth. Natural selection has already pronounced a
satisfactory verdict upon the vast majority of animals which have reached
maturity.’ *

But the criticism retains much force when applied to another theory of evolution _
by the selection of large and conspicuous variations, a theory which certain writers
have all along sought to add to or substitute for that of Darwin. Thus Huxley.
from the very first considered that Darwin had burdened himself unnecessarily in
rejecting per saltum evolution so unreservedly.’ And recently this view has been
revived by Bateson’s work on variation and by the writings of Francis Galton. I
had at first intended to attempt a discussion of this view, together with Lord
Salisbury’s and other objections which may be urged against it; but the more the
two were considered, the more pressing became the claims of the criticism alluded
to at first—the argument that the history of our planet does not allow sufficient
time for a process which all its advocates admit to be extremely slow in its
operation. I select this subject because of its transcendent importance in relation
to organic evolution, and because I hope to show that the naturalist has something
of weight to contribute to the controversy which has been waged intermittently
ever since Lord Kelvin’s paper ‘On Geological Time’* appeared in 1868. It has

' Life and Letters, vol. iii.

* Poulton, Colours of Animals, p. 308. ,

* See his letter to Darwin, November 23, 1859: Life and Letters, vol. ii.

* Trans. Geol. Soc., Glasgow, vol. iii. See also* On the Age of the Sun’s Heat,’
Macmillan, March 1862: reprinted as Appendix to Thomson and Tait, Matwral Philo-

TRANSACTIONS OF SECTION D. 8

been urged by the great worker and teacher who occupied the Presidential Chair
of this Association when it last met in this city that biologists have no right to
take part in this discussion. In his Anniversary Address to the Geological So-
ciety in 1869 Huxley said: ‘ Biology takes her time from geology. . . . If the
geological clock is wrong, all the naturalist will have to do is to modify his
notions of the rapidity of change accordingly.’ This contention is obviously true
as regards the time which has elapsed since the earliest fossiliferous rocks were laid
down. For the duration of the three great periods we must look to the geologist ;
but the question as to whether the whole of organic evolution is comprised within
these limits, or, if not, what proportion of it is so contained, is a question for the
naturalist. The naturalist alone can tell the geologist whether his estimate is suffi-
cient, or whether it must be multiplied by a small or by some unknown but cer-
tainly high figure, in order to account for the evolution of the earliest forms of
life known in the rocks. This, I submit, is a most important contribution to the
discussion.

Before ee further it is right to point out that obviously these argu-
ments will have no weight with those who do not believe that evolution is a
reality. But although the causes of evolution are greatly debated, it may be
assumed that there is no perceptible difference of opinion as to evolution itself, and
this common ground will bear the weight of all the zoological arguments we shall
consider to-day.

It will be of interest to consider first how the matter presented itself to
naturalists before the beginning of this controversy on the age of the habitable
earth. I will content myself with quotations from three great writers on biological
problems—men of extremely different types of mind, who yet agreed in their
conclusions on this subject.

In the original edition of the ‘ Origin of Species,’ (1859), Darwin, arguing from
the presence of trilobites, Nautilus, Lingula, ‘c., in the earliest fossiliferous rocks,
comes to the following conclusion (pages 306, 307) : ‘ Consequently, if my theory
be true, it is indisputable that before the lowest Silurian stratum was deposited
long periods elapsed, as long as, or probably far longer than, the whole interval
from the Silurian age to the present day; and that during these vast yet quite
unknown periods of time the world swarmed with living creatures.’

The depth of his conviction in the validity of this conclusion is seen in the fact
that the passage remains substantially the same in later editions, in which, how-
ever, Cambrian is substituted for Silurian, while the words ‘ yet quite unknown’
are omitted, as a concession, no doubt, to Lord Kelvin’s calculations, which he
then proceeds to discuss, admitting as possible a more rapid change in organic life,
induced by more violent physical changes.'

We know, however, that such concessions troubled him much, and that he
was really giving up what his judgment still approved. Thus he wrote to
Wallace on April 14, 1869: ‘Thomson's views of the recent age of the world have
been for some time one of my sorest troubles... .’ And again, on July 12,
1871, alluding to Mivart’s criticisms, he says: ‘I can say nothing more about
missing links than what I have said. I should rely much on pre-Silurian times ;
but then comes Sir W. Thomson, like an odious spectre.’

Huxley’s demands for time in order to account for pre-Cambrian evolution, as
he conceived it, were far more extensive. Although in 1869 he bade the
naturalist stand aside and take no part in the controversy, he had nevertheless
spoken as a naturalist in 1862, when, at the close of another Anniversary Address
to the same Society, he argued from the prevalence of persistent types ‘that any
admissible hypothesis of progressive modification must be compatible with per-
sistence without progression through indefinite periods;’ and then maintained

sophy, vol. i. part 2, second edition; and ‘On the Secular Cooling of the Earth,’
Royal Society of Edinburgh, 1862,
} 6th ed,, 1872, p. 286.

»
7

{ REPORT—1896.

that ‘should such an hypothesis eventually be proved to be true . . . the conclusion’
will inevitably present itself that the Paleozoic, Mesozoic, and Cainozoic faune
and flor, taken together, bear somewhat the same Da to the whole series
of living beings which have occupied this globe as the existing fauna and flora do
to them.’

Herbert Spencer, in his article on ‘Tllogical Geology’ in the ‘ Universal
Review ’ for July 1859,' uses these words: ‘ Only the last chapter of the earth’s
history has come down to us. The many previous chapters, stretching back to a
time immeasurably remote, have been burnt, and with them all the records of life
we may presume they contained.’ Indeed, so brief and unimportant does Herbert
Spencer consider this last chapter to have been that he is puzzled to account for
‘such evidences of progression as exist’; and finally concludes that they are of no
significance in relation to the doctrine of evolution, but probably represent the
succession of forms by which a newly upheaved land would be peopled. He
argues that the earliest immigrants would be the lower forms a animal and
vegetable life, and that these would be followed by an irregular succession of
higher and higher forms, which ‘ would thus simulate the succession presented by
our own sedimentary series.’

We see, then, what these three great writers on evolution thought on this
subject; they were all convinced that the time during which the geologists con-
cluded that the fossiliferous rocks had been formed was utterly insufficient to
account for organic evolution.

Our object to-day is first to consider the objections raised by physicists against
the time demanded by the geologist, and still more against its multiplication by
the student of organic evolution ; secondly, to inquire whether the present state
of paleeontological and zoological knowledge increases or diminishes the weight of
the threefold opinion quoted aboye—an opinion formed on far more slender
evidence than that which is now available. And if we find this opinion sustained,
it must be considered to have a very important bearing upon the controversy.

The arguments of the physicists are three :—

First, the argument from the observed secular change in the length of the day
the most important element of which is due to tidal retardation. It has been
kmown for a very long time that the tides are slowly increasing the length of our
day. Huxley explains the reason with his usual lucidity: ‘That this must be so
is-obvious, if one considers, roughly, that the tides result from the pull which
the sun and the moon exert upon the sea, causing it to act as a sort of break upon
the solid earth.’ * .

A liquid earth takes a shape which follows from its rate of revolution, and
from which, therefore, its rate of revolution can be calculated. :

The liquid earth consolidated in the form it last assumed, and this shape ha
persisted until now, and informs us of the rate of revolution at the time of con-
solidation. Comparing this with the present rate, and knowing the amount of
lengthening in a given time due to tidal friction, we can calculate the date of
consolidation as certainly less than 1,000 million years ago.

This argument is fallacious, as many mathematicians have shown. The present
shape tells us nothing of the length of the day at the date of consolidation ; for
the earth, even when solid, will alter its form when exposed for a long time to the
action of great forees. As Professor Perry said in a letter to Professor Tait *:
‘I know that solid rock is not like cobbler’s wax, but 1000 million years is a very
long time, and the forces are great.’ Furthermore, we know that the earth is always
altering its shape, and that whole coast-lines are slowly rising or falling, and that
this has been true, at any rate, during the formation of the stratified rocks.

This argument is dead and gone. We are, indeed, tempted to wonder that the

' Reprinted in his Hssays, 1868, vol. i., pp. 324-376.
* Anniv, Address to Geol. Soc., 1869.
> Nature, Jan. 3, 1895.

TRANSACTIONS OF SECTION D. DD

physicist, who was looking about for arguments by which to revise what he con-
ceived to be the hasty conclusions of the geologist as to the age of the earth,
should have exposed himself to such an obvious retort in basing his own con-
clusions as to its age on the assumption that the earth, which we know to be
always changing in shape, has been unable to alter its equatorial radius by a few
miles under the action of tremendous forces constantly tending to alter it, and
having 1,000 million years in which to do the work.

With this flaw in the case it is hardly necessary to insist on our great uncer-
tainty as to the rate at which the tides are lengthening the day.

he spectacle presented by the geologist and biologist, deeply shocked at

Lord Kelvin’s extreme uniformitarianism in the domain of astronomy and cosmic
physics, is altogether too comforting to be passed by without remark; but in thus
indulging in a friendly tu guogue, 1 am quite sure that I am speaking for every
member of this Section in saying that we are in no way behind the members of
Section A in our pride and admiration at the noble work which he has done for
science, and we are glad to take this opportunity of congratulating him on the
half-century of work and teaching—both equally fruitful—which has reached its
completion in the present year.

The second argument is based upon the cooling of the earth, and this is the
one brought forward and explained by Lord Salisbury in his Presidential Address.
It has been the argument on which perhaps the chief reliance has been placed, and
of which the data—so it was believed—were the least open to doubt.

On the Sunday during the meeting of the British Association at Leeds (1890),
1 went for a walk with Professor Perry, and asked him to explain the physical
reasons for limiting the age of the earth to a period which the students of other
sciences considered to be very inadequate. He gave me an account of the data
on which Lord Kelvin relied in constructing this second argument, and expressed
the strong opinion that they were perfectly sound, while, as for the mathematics,
it might be taken for granted, he said, that they were entirely correct. He did
not attach much weight to the other arguments, which he regarded as merely
offering support to the second.

This little piece of personal history is of interest, inasmuch as Professor Perry
has now provided us with a satisfactory answer to the line of reasoning which so
fully satisfied him in 1890. And he was led to a critical examination of the sub-
ject by the attitude taken up by Lord Salisbury in 1894. Professor Perry was
not present at the meeting, but when he read the President’s address, and saw
how other conclusions were ruled out of court, how the only theory of evolution
which commands anything approaching universal assent was set on one side
because of certain assumptions as to the way in which the earth was believed to
have cooled, he was seized with a desire to sift these assumptions, and to inquire
whether they would bear the weight of such far-reaching conclusions. Before
giving the results of his examination, it is necessary to give a brief account of the
argument on which so much has been built.

Lord Kelvin assumed that the earth is a homogeneous mass of rock similar to
that with which we are familiar on the surface. Assuming, further, that the tem-
perature increases, on the average, 1° F’. for every 50 feet of depth near the
surface everywhere, he concluded that the earth would have occupied not less
than twenty, nor more than four hundred, million years in reaching its present
condition from the time when it first began to consolidate and po-sessed a uniform
temperature of 7,000° F.

, in the statement of the argument, we substitute for the assumption of a
homogeneous earth an earth which conducts heat better internally than it does
toward the surface, Professor Perry, whose calculations have been verified by Mr. O.
Heaviside, finds that the time of cooling has to be lengthened to an extent which
depends upon the value assigned to the internal conducting power. If, for
instance, we assume that the deeper part of the earth conducts ten times as well
as the outer part, Lord Kelvin’s age would require to be multiplied by fifty-six.
Even if the conductivity be the same throughout, the increase of density in the

6 ; REPORT—1896.

deeper part, by augmenting the es for heat of unit volume, implies a longer
age than that conceded by Lord Kelvin, If the interior of the earth be fluid or
contain fluid in a honeycomb structure, the rate at which heat can travel would
be immensely increased by convection currents, and the age would have to be
correspondingly lengthened. If, furthermore, such conditions, although not
obtaining now, did obtain in past times, they will have operated in the same
direction.

Professor Tait, in his letter to Professor Perry (published in ‘Nature’ of
January 3, 1895), takes the entirely indefensible position that the latter is bound
to prove the higher iuternal conductivity. The obligation is all on the other side,
and rests with those who have pressed their conclusions hard and carried them
far. Thesa conclusions have been, as Darwin found them, one of our ‘sorest
troubles’; but when it is admitted that there is just as much to be said for another
set of assumptions leading to entirely different conclusions, our troubles are at an
end, and we cease to be terrified by an array of symbols, however unintelligible to
us. It would seem that Professor Tait, without, as far as I can learn, publish
any independent calculation of the age of the earth, has lent the weight of his
authority to a period of 10 million years, or half of Lord Kelvin’s minimum. But
in making this suggestion he apparently feels neifher interest nor responsibility in
establishing the data of the calculations which he borrowed to obtain therefrom a
very different result from that obtained by their author.

Professor Perry’s object was not to substitute a more correct age for that
obtained by Lord Kelvin, but rather to show that the data from which the true
age could be calculated are not really available. We obtain different results by
making different assumptions, and there is no suflicient evidence for accepting one
assumption rather than another. Nevertheless, there is some evidence which
indicates that the interior of the earth in all probability conducts better than the
surface. Its far bigher density is consistent with the belief that it is rich in
metals, free or combined. Professor Schuster concludes that the internal electric
conductivity must be considerably greater than the external. Geologists have
argued from the amount of folding to which the crust has been subjected that
cooling must have taken place to a greater depth than 120 miles, as assumed in
Lord Kelvin’s argument. Professor Perry's assumption would involve cooling to
a much greater depth.

Professor Perry’s conclusion that the age of the habitable earth is lengthened
by increased conductivity is the very reverse of that to which we should be led
by a superticial examination of the case. Professor Tait, indeed, in the letter
to which I have already alluded, has said: ‘ Why, then, drag in mathematics
at all, since it is absolutely obvious that the better conductor the interior in
comparison with the skin, the longer ago must it have been when the whole was
at 7000 F., the state of the skin being as at present?’ Professor Perry, in reply,
pointed out that one mathematician who had refuted the tidal retardation
argument ! had assumed that the conditions described by Professor Tait would
have involved a shorter period of time. And it is probable that Lord Kelvin
thought the same; for he had assumed conditions which would give the result—
so he believed at the time—most acceptable to the geologist and biologist.
Professor Perry's conclusion is very far from obvious, and without the mathematical
reasoning would not be arrived at by the vast majority of thinking men.

The ‘natural man’ without mathematics would say, so far from this being
‘ absolutely obvious,’ it is quite clear that increased conductivity, favouring escape
of heat, would lead to more rapid cooling, and would make Lord Kelvin’s age even
shorter.

The argument can, however, be put clearly without mathematics, and, with
Professor Perry’s help, I am able to state it in a few words. Lord Kelvin’s
assumption of an earth resembling the surface rock in its relations to heat leads to
the present condition of things, namely, a surface gradient of 1° F. for every
50 feet, in 100,000,000 years, more or less. Deeper than 160 miles he imagines

' Rev. M. H, Close in &. Dublin Soe., February 1878.

TRANSACTIONS OF SECTION D. 7

that there has been almost no cooling. If, however, we take one of the cases
put by Professor Perry, and assume that below a depth of four miles there is ten
times the conductivity, we find that after a period of 10,000,000,000 years the
- Raney at the surface is still 1° F. for every 50 feet; but that we have to
escend to a depth of 1,500 miles before we find the initial temperature of
7,000° F. undiminished by cooling. In fact the earth, as a whole, has cooled
far more quickly than under Lord Kelvin’s conditions, the greater conductivity
enabling a far larger amount of the internal beat to escape; but in escaping it
has kept up the temperature gradient at the surface.

Lord Kelvin, replying to Professor Perry’s criticisms, quite admits that the age
at which he had arrived by the use of this argument may be insufficient. Thus,
he says, in his letter': ‘I thought my range from 20 millions to 400 millions was
robably wide enough, but it is quite possible that I should have put the superior
imit a good deal higher, perhaps 4,000 instead of 400.’

The third argument was suggested by Helmholtz, and depends on the life of
the sun, If the energy of the sun is due only to the mutual gravitation of its
parts, and if the sun is now of uniform density, ‘the amount of heat generated by
his contraction to his present volume would have been sufficient to last 18 million
years at his present rate of radiation.’* Lord Kelvin rejects the assumption of
uniform density, and is, in consequence of this change, able to offer a much higher
upward limit of 500 million years.

This argument also implies the strictest uniformitarianism as regards the sun.
We know that other suns may suddenly gain a great accession of energy, so that
their radiation is immensely increased. We only detect such changes when they
are large and sudden, but they prepare us to believe that smaller accessions may be
much more frequent, and perhaps a normal occurrence in the evolution of a sun.
Such accessions may have followed from the convergence of a stream of meteors.
Again, it is possible that the radiation of the sun may have been diminished
and his energy conserved by a solar atmosphere.

Newcomb has objected to these two possible modes by which the life of the
sun may have been greatly lengthened, that a lessening of the sun’s heat by under
a quarter would cause all the water on the earth to freeze, while an increase of much
over half would probably boil it all away. But such changes in the amount of
radiation received would follow from a greater distance from the sun of
154 per cent., and a greater proximity to him of 184 per cent., respectively.
Venus is inside the latter limit, and Mars outside the former, and yet it would be a
very large assumption to conclude that all the water in the former is steam, and
allinthe latter ice. Indeed, the existence of water and the melting of snow on Mars
are considered to be thoroughly well authenticated. It is further possible that in
a time of lessened solar radiation the eart may have possessed an atmosphere
which would retain a larger proportion of the sun’s heat ; and the internal heat of
the earth itself, great lakes of lava under a canopy of cloud for example, may have
played an important part in supplying warmth.

Again we have a greater age if there was more energy available than in
Helmholtz’s hypothesis. Lord Kelvin maintains that this is improbable because
of the slow rotation of the sun, but Perry has given reasons for an opposite
conclusion.

The collapse of the first argument of tidal retardation, aud of the second of the
cooling of the earth, warn us to beware of « conclusion founded on the assumption
that the sun’s energy depends, and has ever depended, on a single source of which
we know the beginning and the end. It may be safely maintained that such a
conclusion has not that degree of certainty which justifies the followers of one
science in assuming that the conclusion of other sciences must be wrong, and in
disregarding the evidence brought forward by workers in other lines of research.

We must freely admit that this third argument has not yet fully shared the fate

' Nature, January 3, 1895.
* Newcomb’s Popular Astronomy, p. 523,

8 ' REPORT—1896.

of the two other lines of reasoning. Indeed, Professor George Darwin, although
attacking these latter, agrees with Lord Kelvin in regarding 500 million years as
the maximum life of the sun!

We may observe, too, that 500 million years is by no means to be despised: a
great deal may happen in such a period of time. Although I should be very so
to say that it is sufficient, it is a very different offer from Professor Tait’s
10 million,

In drawing up this account of the physical arguments, I owe almost everythin
to Professor Perry for his articles in ‘ Nature’ (January 3 and April 18, 1895),
and his kindness in explaining any difficulties that arose. I have thought it right
to enter into these arguments in some detail, and to consume a considerable pro-
portion of our time in their discussion. This was imperatively necessary, because
they claimed to stand as barriers across our path, and, so long as they were admitted
to be impassable, any further progress was out of the question. What I hope has
been an unbiassed examination has shown that, as barriers, they are more imposin
than effective; and we are free to proceed, and to look for the conclusions warran
by our own evidence. In this matter we are at one with the geologists; for, as
has been already pointed out, we rely on them for an estimate of the time occupied
by the deposition of the stratified rocks, while they rely on us for a conclusion as to
how far this period is sufficient for the whole of organic evolution.

First, then, we must briefly consider the geological argument, and I cannot do
better than take the case as put by Sir Archibald Geikie in his Presidential Address
to this Association at Edinburgh in 1892.

Arguing from the amount of material removed from the land by denudin,
agencies, and carried down to the sea by rivers, he showed that the time require
to reduce the height of the land by one foot, varies, according to the activity of the
agencies at work, from 730 years to 6,800 years. But this also supplies a measure
of the rate of deposition of rock; for the same material is laid down elsewhere,
and would of course add the same height of one foot to some other area equal in
size to that from which it was removed. F

The next datum to be obtained is the total thickness of the stratified rocks
from the Cambrian system to the present day. ‘On a reasonable computation
these stratified masses, where most fully developed, attain a united thickness of
not less than 100,000 feet. If they were all laid down at the most rapid recorded
rate of denudation, they would require a period of seventy-three millions of years
for their completion. If they were laid down at the slowest rate, they would
demand a period of not less than 680 millions.’

The argument that geological agencies acted much more vigorously in past
times he entirely refuted by pointing to the character of the deposits of which the
stratified series is composed. ‘We can see no proof whatever, nor even any
evidence which suggests that on the whole the rate of waste and sedimentation
was more rapid during Mesozoic and Paleozoic time than it is to-day. Had there
been any marked difference in this rate from ancient to modern times, it would be
incredible that no clear proof of it should have been recorded in the crust of the
earth,’

It may therefore be inferred that the rate of deposition was no nearer the more
rapid than the slower of the rates recorded above, and, if so, the stratified rocks
would have been laid down in about 400 million years.

There are other arguments favouring the uniformity of conditions throughout
the time during which the stratified rocks were laid down, in addition to those
which are purely geological and depend upon the character of the rocks themselves.
na ee more biological than geological, these arguments are best considered
rere, ,

The geological agency to which attention is chiefly directed by those who desire
to hurry up the phenomena of rock formation is that of the tides. But it seems

British Association Revorts 1886, pp. 514-518,

TRANSACTIONS OF SECTION D. 9

certain that the tides were not sufficiently higher in Silurian times to prevent the
deposition of certain beds of great thickness under conditions as tranquil as any of
which we have evidence in the case of a formation extending over a large area.
From the character of the organic remains it is known that these beds were laid
down in the sea, and there are the strongest grounds for believing that they were
accumulated along shores and in fairly shallow water. The remains of extremely
delicate organisms are found in immense numbers, and over a very large area.
The recent discovery, in the Silurian system of America, of trilobites, with their
long delicate antennz perfectly preserved, proves that in one locality (Rome, New
York State) the tranquillity of deposition was quite as profound as in any locality
yet discovered on this side of the Atlantic.

There are, then, among the older Palwozoic rocks a set of deposits than which
we can imagine none better calculated to test the force of the tides; and we find
that they supply evidence for exceptional tranquillity of conditions over a long
period of time.

There is other evidence of the permanence, throughout the time during which
the stratified rocks were deposited, of conditions not very dissimilar from those
which obtain to-day. Thus the attachments of marine organisms, which are per-
manently rooted to the bottom or on the shores, did not differ in strength from
those which we now find—an indication that the strains due to the movements
of the sea did not greatly differ in the past.

We have evidence of a somewhat similar kind to prove uniformity in the
movements of the air. The expanse of the wings of flying organisms certainly
does not differ in a direction which indicates any greater violence in the atmo-
spheric conditions. Before the birds had become dominant among the larger
flying organisms, their place was taken by the flying reptiles, the pterodactyls,
and before the appearance of these we know that, in Paleozoic times, the insects
were of immense size, a dragon-fly from the Carboniferous rocks of France being
upwards of 2 feet in the expanse of its wings. As one group after another of
widely dissimilar organisms gained control of the air, each was in turn enabled to
increase to the size which was best suited to such an environment, but we find that
the limits which obtain to-day were not widely different in the past, And this is
evidence for the uniformity in the strains due to wind and storm no less than to
those due to gravity. Furthermore, the condition of the earth’s surface at present
shows us how extremely sensitive the flying organism is to an increase in the
former of these strains, when it occurs in proximity to the sea. Thus it is well
known that an unusually large proportion of the Madeiran beetles are wingless,
while those which require the power of flight possess it in a stronger degree than
on continental areas. This évitution in two directions is readily explained by the
destruction by drowning of the winged individuals of the species which can
manage to live without the power of flight, and of the less strongly winged indi-
viduals of those which need it. Species of the latter kind cannot live at all in the
far more stormy Kerguelen Land, and the whole of the insect fauna is wingless.

The size and strength of the trunks of fossil trees afford, as Professor George
Darwin has pointed out, evidence of uniformity in the strains due to the condition
of the atmosphere.

We can trace the prints of raindrops at various geological horizons, and in some
cases found in this country it is even said that the eastern side of the depressions
is the more deeply pitted, proving that the rain drove from the west, as the great
majority of our storms do to-day.

When, therefore, we are accused of uniformitarianism, as if it were an entirely
unproved assumption, we can at any rate point to a large body of positive evidence
which supports our contention, and the absence of any evidence against it.
Furthermore, the data on which we rely are likely to increase largely, as the result
of future work.

After this interpolation, chiefly of biological argument in support of the geolo-
gist, I cannot do better than bring the geological evidence to a close in the words
which conclude Sir Archibald Geikie’s address : ‘After careful reflection on the
subject, I affirm that the geological record furnishes a mass of evidence which no

pd3

10 REPORT—1896.

arguments drawn from other departments of Nature can explain away, and which,
it seems to me, cannot be satisfactorily interpreted save with an allowance of time
much beyond the narrow limits which recent physical speculation would concede.’

In his letter to Professor Perry,' Lord Kelvin says:—

‘So far as underground heat alone is concerned, you are quite right that m
estimate was 100 million, and please remark ? that that is all Geikie wants; but
I should be exceedingly frightened to meet him now with only 20 million in my
mouth.’

We have seen, however, that Geikie considered the rate of sedimentation to
be, on the whole, uniform with that which now obtains, and this would demand
a period of nearly 400 million years. He points out furthermore that the time
must be greatly increased on account of the breaks and interruptions which occur
in the series, so that we shall probably get as near an estimate as is possible from
the data which are available by taking 450 million as the time during which the

stratified rocks were formed.

Before leaving this part of the subject, I cannot refrain from suggesting a line
of enquiry which may very possibly furnish important data for checking the
estimates at present formed by geologists, and which, if the mechanical difficulties
can be overcome, is certain to lead to results of the greatest interest and importance.
Ever since the epoch-making voyage of the ‘Challenger,’ it has been known that
the floor of the deep oceans outside the shallow shelf which fringes the continental
areas is covered by a peculiar deposit formed entirely of meteoric and volcanic
dust, the waste of floating pumice, and the hard parts of animals living in the
ocean, Of these latter only the most resistant can escape the powerful solvent
agencies. Many observations prove that the accumulation of this deposit is
extremely slow. One indication of this is especially convincing: the teeth of sharks
and the most resistant part of the skeleton—the ear- bones—of whales are so thickly
spread over the surface that they are continually brought up in the dredge, while
sometimes a single haul will yield a large number of them. Imagine the count-
less generations of sharks and whales which must have succeeded each other in
order that these insignificant portions of them should be so thickly spread over
that vast area which forms the ocean floor. We have no reason to suppose that
sharks and whales die more frequently in the deep ocean than in the shallow
fringing seas; in fact, many observations point in the OREO direction, for
wounded and dying whales often enter shallow creeks and inlets, and not uncom-
monly become stranded. And yet these remains of sharks and whales, although
well known in the stratified rocks which were laid down in comparatively shallow
water and near coasts, are only found in certain beds, and then in far less abun-
dance than in the oceanic deposit. We can only explain this difference by es gd
that the latter accumulate with such almost infinite slowness as compared with
the continental deposits that these remains form an important and conspicuous
constituent of the one, while they are merely found here and there when looked
for embedded in the other. The rate of accumulation of all other constituents is
so slow as to leave a layer of teeth and ear-bones uncovered, or covered by so thin
a deposit that the dredge can collect them freely. Dr. John Murray calculates
that only a few inches of this deposit have accumulated since the Tertiary Period.
These most interesting facts prove furthermore that the great ocean basins and
continental areas have occupied the same relative positions since the formation of the
first stratified rocks ; for no oceanic deposits are found anywhere in the latter. We
know the sources of the oceanic deposit, and it might be possible to form an esti-
mate, within wide limits, of its rate of accumulation. If it were possible to
ascertain its thickness by means of a boring, some conclusions as to the time which
has elapsed during the lifetime of certain species—perhaps even the lifetime of the
oceans themselves—might be arrived at. Lower down the remains of earlier
species would probably be found. The depth of this deposit and its character at

1 Nature, Jan. 3, 1895.
2 P. L. and A,, Vol. ii., p. 87.

TRANSACTIONS OF SECTION D, 11

deeper levels are questions of overwhelming interest; and perhaps even more so is
the question as to what lies beneath. Long before the ‘Challenger’ had proved
the persistence of oceanic and continental areas, Darwin, with extraordinary fore-
sight, and opposed by all other naturalists and geologists, including his revered
teacher, Tyall, had come to the same conclusion. His reasoning on the subject is
so convincing that it is remarkable that he made so few converts, and this is all
the more surprising since the arguments were published in the ‘ Origin of Species,’
which in other respects produced so profound an effect. In speculating as to the
rocks in which the remains of the ancestors of the earliest known fossils may still
exist, he suggested that, although the existing relationship between the positions
of our present oceans and continental areas is of immense antiquity, there is no
reason for the belief that it has persisted for an indefinite period, but that at some
time long antecedent to the earliest known fossiliferous rocks ‘continents may
have existed where oceans are now spread out; and clear and open oceans may
have existed where our continents now stand.’ Not the least interesting result
would be the test of this hypothesis, which would probably be forthcoming as the
result of boring into the floor of a deep ocean; for although, as Darwin pointed
out, it is likely enough that such rocks would be highly metamorphosed, yet it
might still be possible to ascertain whether they had at any time formed part of a
continental deposit, and perhaps to discover much more than this, Such an under-
taking might be carried out in conjunction with other investigations of the highest
interest, such as the attempt to obtain a record of the swing of a pendulum at the
bottom of the ocean.

We now come to the strictly biological part of our subject—to the inquiry as
to how much of the whole scheme of organic evolution has been worked out in
the time during which the fossiliferous rocks were formed, and how far, therefore,
the time required by the geologist is sufficient.

It is first necessary to consider Lord Kelvin’s attempt to rescue us from the
dilemma in which we were placed by the insufficiency of time for evolution—the
suggestion that life may have reached the earth on a meteorite. According to
this view, the evolution which took place elsewhere may have been merely com-
pleted, in a comparatively brief space of time, on our earth.

We Imow nothing of the origin of life here or elsewhere, and our only
attitude towards this or any other hypothesis on the subject is that of the
anxious inquirer for some particle of evidence. But a few brief considerations
will show that no escape from the demands for time can be gained in this way.

Our argument does not deal with the time required for the origin of life, or
for the development of the lowest beings with which we are acquainted from the
first formed beings, of which we know nothing. Both these processes may have
required an immensity of time ; but as we know nothing whatever about them, and
have as yet no prospect of acquiring any information, we are compelled to confine
ourselves to as much of the process of evolution as we can infer from the structure
of living and fossil forms—that is, as regards animals, to the development of the
simplest into the most complex Protozoa, the evolution of the Metazoa from the
Protozoa, and the branching of the former into its numerous Phyla, with all their
Classes, Orders, Families, Genera, and Species. But we shall find that this is
quite enough to necessitate a very large increase in the time estimated by the
geologist.

The Protozoa, simple and complex, still exist upon the earth in countless
species, together with the Metazoan Phyla. Descendants of forms which in their
day constituted the beginning of that scheme of evolution which I have defined
above, descendants, furthermore, of a large proportion of those forms which, age
after age, constituted the shifting phases of its onward progress, still exist, and in
a sufficiently unmodified condition to enable us to reconstruct, at any rate in
mere outline, the history of the past. Innumerable details and many phases of
supreme importance are still hidden from us, some of them perhaps never to be
recovered. But this frank admission, and the eager and premature attempts to
expound too much, to go further than the evidence permits, must not be allowed

12 : REPORT—1896.

to throw an undeserved suspicion upon conclusions which are sound and well
supported, upon the firm conviction of every zoologist that the general trend of
eyolution has been, as I have stated it, that each of the Metazoan_Phyla originated,
directly or indirectly, in the Protozoa.

The meteorite theory would, however, require that the process of evolution
went backward on a scale as vast as that on which it went forward, that certain
descendants of some central type, coming to the earth on a meteorite, gradually
lost their Metazoan complexity and developed backward into the Protozoa, throw-
ing off the lower Metazoan Phyla on the way, while certain other descendants
evolved all the higher Metazoan groups. Such a process would shorten the
period of evolution by half, but it need hardly be said that all available evidence is
entirely against it.

The only other assumption by means of which the meteorite hypothesis would
serve to shorten the time is even more wild and improbable. Thus it might be
supposed that the evolution which we believe to have taken place on this earth,
really took place elsewhere—at any rate as regards all its main lines—and that
samples of all the various phases, including the earliest and simplest, reached us
by a regular meteoric service, which was established at some time after the com-
pletion of the scheme of organic evolution. Hence the evidences which we study
would point to an evolution which occurred in some unknown world with an age
which even Professor Tait has no desire to limit.

If these wild assumptions be rejected, there remains the supposition that, if life
was brought by a meteorite, it was life no higher than that of the simplest Proto-
zoon—a supposition which leaves our argument intact. The alternative supposition,
that one or more of the Metazoan Phyla were introduced in this way while the
others were evolved from the terrestrial Protozoa, is hardly worth consideration.
In the first place, some evidence of a part in a common scheme of evolution is to
be found in every Phylum. In the second place, the gain would be small; the
arbitrary assumption would only affect the evidence of the time required for evolu-
tion derived from the particular Phylum or Phyla of supposed meteoric origin.

The meteoric hypothesis, then, can only affect our argument by making the

most improbable assumptions, for which, moreover, not a particle of evidence can.

be brought forward.

We are therefore free to follow the biological evidence fearlessly. It is neces-
sary, in the first place, to.expand somewhat the brief outline of the past history of
the animal kingdom, which has already been given. Since the appearance of the
‘Origin of Species,’ the zoologist, in making his classifications, has attempted as far
as possible to set forth a genealogical arrangement. Our purpose will be served by
an account of the main outlines of a recent classification, which has been framed

with a due consideration for all sides of zoological research, new and old, and~

which has met with general approval. Professor Lankester divides the animal
kingdom into two grades, the higher of which, the Enterozoa (Metazoa), were
derived from the lower, the Plastidozoa (Protozoa). Each of these grades is again
divided into two sub-grades, and each of these is again divided into Phyla, cor-
responding more or less to the older Sub-Kingdoms. Beginning from below, the most
primitive animals in existence are found in the seven Phyla of the lower Protozoan
sub-grade, the Gymnomyxa. Of these unfortunately only two, the Reticularia (Fora-
minifera) and Radiolaria, possess a structure which renders possible their preservation
in the rocks, The lowest and simplest of these Gymnomyxa represent the starting-
point of that scheme of organic evolution which we are considering to-day. The
higher order of Protozoan life, the sub-grade Corticata, contains three Phyla, no one
of which is available in the fossil state. They are, however, of great interest and
importance to us as showing that the Protozoan type assumes a far higher organi-
sation on its way to eyolye the more advanced grade of animal life. The first-
formed of these latter are contained in the two Phyla of the sub-grade Coslentera,
the Porifera or Sponges, and the Nematophora or Corals, Sea-Anemones, Hy-
drozoa and allied groups, Both of these Phyla are plentifully represented in the

fossil state. It is considered certain that the latter of these, the Nematophora, —

TRANSACTIONS OF SECTION D. 13

ave rise to the higher sub-grade, the Colomata, or animals with a cwlom or
Body-caviéy surrounding the digestive tract. ‘This latter includes all the remain-
ing species of animals in nine Phyla, five of which are found fossil—the Echino-
derma, Gephyrea, Mollusca, Appendiculata, and Vertebrata.

Before proceeding further, I wish to lay emphasis on the immense evolutionary
history which must have been passed through before the ancestor of one of the
higher of these nine Phyla came into being. Let us consider one or two examples,
since the establishment of this position is of the utmost importance for our argu-
ment. First, consider the past history of the Vertebrata,—of the common ancestor
of our Balanoglossus, Tunicates, Amphioxus, Lampreys, Fishes, Dipnoi, Amphibia,
Reptiles, Birds, and Mammals. Although zoologists differ very widely in their
opinions as to the affinities of this ancestral form, they all agree in maintaining
that it did not arise direct from the Nematophora in the lower sub-grade of
Metazoa, but that it was the product of a long history within the Coslomate sub-
grade. The question as to which of the other C@lomate Phyla it was associated
with will form the subject of one of our discussions at this meeting; and I will
therefore say no more upon this period of its evolution, except to point out that
the very question itself, ‘the ancestry of Vertebrates,’ only means a rela-
tively small part of the evolutionary history of the Vertebrate ancestor within
the Celomate group. For when we have decided the question of the other
Ceelomate Phylum or Phyla to which the ancestral Vertebrate belonged, there
remains of course the history of that Phylum or those Phyla earlier than the point
at which the Vertebrate diverged, right back to the origin of the Coelomata; while,
beyond and below, the wide gulf between this and the Coelentera had to be
crossed, and then, probably after a long history as a Coelenterate, the widest and
most significant of all the morphological intervals—that between the lowest
Metazoon and the highest Protozoon—was trayersed. But this was by no means
all. There remains the history within the higher Protozoan sub-grade, in the
interval from this to the lower, and within the lower sub-grade itself, until we
finally retrace our steps to the lowest and simplest forms. It is impossible to
suppose that all this history of change can have been otherwise than immensely
pacuerd ; for it will be shown below that all the available evidence warrants the

elief that the changes during these earlier phases were at least as slow as
those which occurred later.

Tf we take the history of another of the higher Phyla, the Appendiculata, we
find that the evidence points in the same direction. The common ancestor of our
Rotifera, earthworms, leeches, Peripatus, centipedes, insects, Crustacea, spiders
and scorpions, and forms allied to all these, is generally admitted to have been
Cheetopod-like, and probably arose in relation to the beginnings of certain other
Ccelomata Phyla, such as the Gephyrea and perhaps Mollusca. At the origin of
the Coelomate sub-grade the common ancestor of all Coelomate Phyla is reached,
and its evolution has been already traced in the case of the Vertebrata.

What is likely to be the relation between the time required for the evolution
of the ancestor of a Coelomate Phylum and that required for the evolution, which
subsequently occurred, within the Phylum itself? The answer to this question
depends mainly upon the rate of evolution in the lower parts of the animal
kingdom as compared with that in the higher. Contrary, perhaps, to anticipation,
we find that all the evidences of rapid evolution are confined to the most advanced
of the smaller groups within the highest Phyla, and especially to the higher
Classes of the Vertebrata. Such evidence as we have strongly indicates the most
remarkable persistence of the lower animal types. Thus in the Class Imperforata
of the Reticularia (Foraminifera) one of our existing genera (Saecamina) occurs
in the Carboniferous strata, another (Trochammina) in the Permian, while a
single new genus (Receptaculites) occurs in the Silurian and Devonian. The
evidence from the Class Perforata is much stronger, the existing genera Nodosaria,
Dentalina, Textularia, Grammostomum, Valvulina, and Nummulina all occurring
in the Carboniferous, together with the new genera Archediscus (?) and Fusulina.

I omit reference to the much-disputed Hozoon from the Laurentian rocks far
below the horizon, which for the purpose of this address I am considering as the

14 REPORT—1896,

lowest fossiliferous stratum. We are looking forward to the new light which will
be thrown upon this form in the communication of its veteran defender, Sir
William Dawson, whom we are all glad to welcome.

Passing the Radiolaria, with delicate skeletons less suited for fossilisation, and
largely pelagic and therefore less likely to reach the strata laid down along the
fringes of the continental areas, the next Phylum which is found in a fossil state
is that of the Porifera, including the sponges, and divided into two Classes, the
Calcispongiz and Silicospongis#. Although the fossilisation of sponges is in many
cases very incomplete, distinctly recognisable traces can be nae out in a large
number of strata. From these we know that representatives of all the groups of
hoth Classes (except the Halisarcide, which have no hard parts) occurred in the
Silurian, Devonian, and Carboniferous systems, The whole Phylum is an example of
long persistence with extremely little change. And the same is true of the Nema-
tophora: new groups indeed come in, sometimes extremely rich in species, such as
the Palwozoic Rugose corals and Graptolites; but they existed side by side with
representatives of existing groups, and they are not in themselves primitive or
ancestral. A study of the immensely numerous fossil corals reveals no adyance in
organisation, while researches into the structure of existing Aleyonaria and Hydro-
corallina have led to the interpretation of certain Paleozoic forms which were pre-
viously obscure, and the conclusion that they find their place close beside the
living species.

All available evidence points to the extreme slowness of progressive evolu
tionary changes in the Ccelenterate Phyla, although the Protozoa, if we may judge
by the Reticularia (Foraminifera), are even more conservative.

When we consider later on the five Coslomate Phyla which occur fossil, we
shall find that the progressive changes were slower and indeed hardly appreciable
in the two lower and less complex Phyla, viz.: the Echinoderma, and Gephyrea,
as compared with the Mollusca, Appendiculata, and Vertebrata.

Within these latter Phyla we have evidence for the evolution of higher groups
presenting a more or less marked advance in organisation. And not only is the
rate of development more rapid in the highest Phyla of the animal kingdom, but

it appears to be most rapid when dealing with the highest animal tissue, the ~

central nervous system. The chief, and doubtless the most significant, difference
between the early Tertiary mammals and those which succeeded them, between the
Secondary and Tertiary reptiles, between man and the mammals most nearly
allied to him, is a difference in the size of the brain. In all these cases an enormous
increase in this, the dominant tissue of the body, has taken place in a time which,
geologically speaking, is very brief.

When speaking later on upon the evolution which has taken place within the

Phyla, further details upon this subject will be given, although in this as in other —

cases the time at our disposal demands that the exposition of evidence must
largely yield to an exposition of the conclusions which follow from its study.
And undoubtedly a study of all the available evidence points very strongly to the
conclusion that in the lower grade, sub-grades, and Phyla of the animal kingdom
evolution has been extremely slow as compared with that in the higher. We do
not know the reason. It may be that this remarkable persistence through the
stratified series of deposits is due to an innate fixity of constitution which has
rigidly limited the power of variation; or, more probably perhaps, that the lower
members of the animal kingdom were, as they are now, more Conn confined to
particular environments, with particular sets of conditions, with which they had to
cope, and, this being successfully accomplished, natural selection has done little
more than keep up a standard of organisation which was sufficient for their needs;
while the higher and more aggressive forms ranging over many environments, and
always prone to encounter new sets of conditions, were compelled to undergo respon-
sive changes or to succumb. But whatever be the cause, the fact remains, and is of
the highest importance for our argument. When the ancestor of one of the higher

Phyla was associated with the lower Phyla of the Coelomate sub-grade, when ~

further back it passed through a Ccelenterate, a higher Protozoan, and finally a
lower Protozoan phase, we must believe that its evolution was probably very slow

TRANSACTIONS OF SECTION D. 15

as compared with the rate which it subsequently attained. But this conclusion is
of the utmost importance ; for the history contained in the stratified rocks nowhere
reveals to us the origin of a Phylum. And this is not mere negative evidence, but
ositive evidence of the most unmistakable character. All the five Calomate
Ph la which occur fossil appear low down in the Palsozoic rocks, in the Silurian
or Cambrian strata, and they are represented by forms which are very far from being
primitive, or, if primitive, are persistent types, such as Chiton, which are now
living. Thus Vertebrata are represented by fishes, both sharks and ganoids; the
Appendiculata by cockroaches, scorpions, Limulids, Trilobites, and many Crustacea ;
the Mollusca by Nautilus and numerous allied genera, by Dentalium, Chiton,
Pteropods, and many Gastropods and Lamellibranchs; the Gephyrea by very
numerous Brachiopods, and many Polyzoa ; the Echinoderma by Crinoids, Cystoids,
Blastoids, Asteroids, Ophiuroids, and Echinoids. It is just conceivable, although,
as I believe, most improbable, that the Vertebrate Phylum originated at the time
when the earliest known fossiliferous rocks were laid down. It must be remem-
bered, however, that an enormous morphological interval separates the fishes which
appear in the Silurian strata from the lower branches, grades, and classes of the
Phylum in which Balanoglossus, the Ascidians, Amphioxus, and the Lampreys are
placed. The earliest Vertebrates to appear are, in fact, very advanced members of
the Phylum, and, from the point of view of anatomy, much nearer to man than to
Amphioxus. If, however, we grant the improbable contention that so highly
organised an animal as a shark could be evolved from the ancestral vertebrate in
the period which intervened between the earliest Cambrian strata and the Upper
Silurian, it is quite impossible to urge the same with regard to the other Phyla.
Tt has been shown above that when these appear in the Cambrian and Silurian,
they are flourishing in full force, while their numerous specialised forms are a
positive proof of a long antecedent history within the limits of the Phylum.

If, however, we assume for the moment that the Phyla began in the Cambrian,
the geologist’s estimate must still be increased considerably, and perhaps doubled,
in order to account for the evolution of the higher Phyla from forms as low as
many which are now known upon the earth ; unless, indeed, it is supposed, against
the whole weight of all such evidence as is available, that the evolutionary history
in these early times was comparatively rapid.

To recapitulate, if we represent the history of animal evolution by the form of
a tree, we find that the following growth took place in some age antecedent to the
earliest fossil records, before the establishment of the higher Phyla of the Animal
Kingdom. The main trunk representing the lower Protozoa divided, originating
the higher Protozoa; the latter portion again divided, probably in a threefold man-
ner, originating the two lowest Metazoan Phyla, constituting the Ceelentera. The
branch representing the higher of these Phyla, the Nematophora, divided, origina-
ting the lower Coelomate Phyla, which again branched and originated the higher
Phyla. And, as has been shown above, the relatively ancestral line, at every
stage of this complex history, after originating some higher line, itself continued
down to the present day, throughout the whole series of fossiliferous rocks, with
but little change in its general characters, and practically nothing in the way of
progressive evolution. Evidences of marked advance are to be found alone in the
most advanced groups of the latest highest products—the Phyla formed by the
last of these divisions.

It may be asked how is it possible for the zoologist to feel so confident
as to the past history of the various animal groups, I have already explained
that he does not feel this confidence as regards the details of the history,
but as to its general lines, The evidence which leads to this conviction jis
based upon the fact that animal structure and mode of development can be, and
have been, handed down from generation to generation from a period far more
remote than that which is represented by the earliest fossils; that fundamental
facts in structure and development may remain changeless amid endless changes of
a more general character ; that especially favourable conditions have preserved
ancestral forms comparatively unchanged. Working upon this material, com-

16 REPORT—1896.

parative anatomy and embryology can reconstruct for us the general aspects of a
history which took place long before the Cambrian rocks were deposited, This
line of reasoning may appear very speculative and unsound, and it may easily
become so when pressed too far. But applied with due caution and reserye, it
may be trusted to supply us with an immense amount of valuable information
which cannot be obtained in any other way. Furthermore, it is capable of stand-
ing the very true and searching test eupplie? by the verification of predictions
made on its authority. Many facts taken together lead the zoologist to be-
lieve that A was descended from C through B; but if this be true, B should
possess certain characters which are not known to belong to it. Under the in-
spiration of hypothesis a more searching investigation is made, and the characters
are found. Again, that relatively small amount of the whole scheme of animal
evolution which is contained in the fossiliferous rocks has furnished abundant
confirmation of the validity of the zoologist’s method. The comparative anatomy
of the higher Vertebrate Classes leads the zoologist to believe that the toothless
beak and the fused caudal vertebra of a bird were not ancestral characters, but
were at some time derived from a condition more conformable to the general plan
of vertebrate construction, and especially to that of reptiles. Numerous secondary
fossils prove to us that the birds of that time possessed teeth and separate caudal
vertebra, culminating in the long lizard-like tail of Archeopteryx.

Prediction and confirmation of this kind, both zoological and paleontological,
have been going on ever since the historic point of view was adopted by the
naturalist as the outcome of Darwin’s teaching, and the zoologist may safely claim
that his method, confirmed by paleontology so far as evidence is available, may be
extended beyond the period in which such evidence is to be found.

And now our last endeayour must be to obtain some conception of the amount
of evolution which has taken place within the higher Phyla of the Animal Aingdop
during the period in which the fossiliferous rocks were deposited. The evidence
must necessarily be considered very briefly, and we shall be compelled to omit the
Vertebrata altogether.

The Phylum Appendiculata is divided by Lankester into three branches, the
first containing the Rotifera, the second the Chetopoda, the third the Arthropoda. OF
these the second is the oldest, and gaye rise to the other two, or at any rate to
the Arthropoda, with which we are alone concerned, inasmuch as the fossil records
of the others are insufficient. The Arthropoda contain seven Classes, divided into
two grades, according to the presence or absence of antennse—the Ceratophora,
containing the Peripatoidea, the Myriapoda, and the Hexapoda (or insects); the
Acerata, containing the Crustacea, Arachnida, and two other classes (the Pantopoda
and Tardigrada) which we need not consider. The first Class of the antenna-
bearing group contains the single genus Peripatus—one of the most interesting:
and ancestral of animals, as proved by its structure and development, and by its
immense geographical range. Ever since the researches of Moseley and Balfour,
extended more recently by those of Sedgwick, it has been recognised as one of the
most beautiful of the connecting links to be found amongst animals, uniting the
antenna-bearing Arthropods, of which it is the oldest member, with the Chatopods.
Peripatus is a magnificent example of the far-reaching conclusions of zoology, and
of its superiority to paleontology as a guide in unravelling the tangled history of
animal evolution. Peripatus is alive to-day, and can be studied in all the details
of its structure and development; it is infinitely more ancestral, and.tells of a far
more remote past than any fossil Arthropod, although such fossils are well known
in all the older of the Paleozoic rocks. And yet Peripatus is not known as a
fossil. Peripatus has come down, with but little change, from a time, on a mode-
rate estimate, at least twice as remote as the earliest known Cambrian fossil.
The agencies which, it is believed, have crushed and heated the Archean rocks
so as to obliterate the traces of life which they contained were powerless to efface
this ancient type, for, although the passing generations may have escaped record,
the likeness of each was stamped on that which succeeded it, and has continued
down to the present day. It is, of course, a perfectly trite and obvious conclusion,

—

TRANSACTIONS OF SECTION D. 17

but not the less one to be wondered at, that the force of heredity should thus far
outlast the ebb and flow of terrestrial change throughout the vast period over
which the geologist is our guide.

If, however, the older Palseozoie rocks tell us nothing of the origin of the
antenna-bearing Arthropods, whut do they tell us of the history of the Myriapod
and Hexapod Classes ?

The Myriapods are well represented in Paleozoic strata, two species being
found in the Devonian and no less than thirty-two in the Carboniferous. Although
placed in an Order (Archipolypoda) separate from those of living Myriapods, these
species are by no means primitive, and do not supply any information as to the
steps by which the Class arose. The imperfection of the record is well seen in the
traces of this Class; for between the Carboniferous rocks and the Oligocene there
are no remains of undoubted Myriapods.

We now come to the consideration of insects, of which an adequate discussion
would occupy a great deal too much of your time. An immense number of species
are found in the Palwozoic rocks, and these are considered by Scudder, the great
authority on fossil insects, to form an Order, the Paleodictyoptera, distinct from any
of the existing Orders. The latter, he believes, were evolved from the former in
Mesozoic times. These views do not appear to derive support from the wonderful
discoveries of M. Brongniart ' in the Upper Carboniferous of Commentry in the
Department of Allier in Central France. Concerning this marvellous assemblage of
species, arranged by their discoverer into 46 genera and 10] species, Seudder truly
Says:

‘Our Imowledge of Paleozoic insects will have been increased three or fourfold
at a single stroke. .... No former contribution in this field can in any way
compare with it, nor even all former contributions taken together.’ *

When we remember that the group of fossil insects, of which so much can be
affirmed by so great an authority as Scudder, lived at one time and in a single
‘locality, we cannot escape the conclusion that the insect fauna of the habitable
earth during the whole Paleozoic period was of immense importance and variety.
Our knowledge of this single group of species is largely due to the accident that coal-
mining in Commentry is carried on in the open air.

Now, these abundant remains of insects, so far from upholding the view that
the existing orders had not been developed in Paleozoic times, are all arranged by
Brongniart in four out of the nine Orders into which insects are usually divided,
viz. the Orthoptera, Neuroptera, Thysanoptera, and Homoptera. The importance
of the discovery is well seen in the Neuroptera, the whole known Paleozoic
fauna of this Order being divided into 45 genera and 99 species, of which 33
and 72 respectively have ee found at Commentry.

Although the Carboniferous insects of Commentry are placed in new families,
some of them come wonderfully near those into which existing insects are classified,
and obviously form the precursors of these. This is true of the Blattide, Phasmide,
Acridiide, and Locustide among the Orthoptera, the Perlide among the
Neuroptera, and the Fulgoride among the Homoptera. The differences which
separate these existing families from their Carboniferous ancestors are most
interesting and instructive. Thus the Carboniferous cockroaches possessed ovi-
positors, and probably laid their eggs one at a time, while ours are either vivi-
parous or lay their eggs in a capsule. The Protophasmid resemble living species
in the form of the head, antenne, legs, and body; but while our species are either
wingless or, with the exception of the female Phyllide, have the anterior pair
reduced to tegmina, useless for flight, those of Paleozoic times possessed four well-
developed wings. The forms representing locusts and grasshoppers (Paleeacridiide)
possessed long slender antenne like the green grasshoppers (Locustide), from
which the Acridiidee are now distinguished by their short antenne. The diver-
gence and specialisation which is thus shown is amazingly small in amount. In

1 Charles Brongniart.—‘ Recherches pour servir 4 l'Histoire des Insectes fossiles
on temps primaires, précédées d’une Etude sur la nervation des ailes des Insectes.’
1894. hes
"28, H. Scudder, Am. Journ. Sci. vol. xlvii., February 1894. Art, viii.

18 REPORT—1896.

the vast period between the Upper Carboniferous rocks and the present day the cock-
roaches have gaiued a rather different wing venation, aud have succeeded in laying
their eggs in a manner rather more specialised than that of insects in general; the
stick insects and leaf insects have lost or reduced their wings, the grasshoppers
have shortened their antennw, These, however, are the insects which most closely
resemble the existing species; let us turn to the forms which exhibit the greatest
differences. Many species haye retained in the adult state characters which are
now contined to the larval stage of existence, such as the presence of tracheal gills
on the sides of the abdomen. In some, the two membranes of the wing were not
firmly fixed together, so that the blood could circulate freely between them, On
the other hand, they are not very firmly tixed together in existing insects. Another
important point was the condition of the three thoracic segments, which were quite
distinct and separate, instead of being fused as they are now in the imago stage.
This external difference probably also extended to the nervous system, so that the
thoracic ganglia were separate instead of concentrated. The most interesting
distinction, however, was the possession by many species of a pair of prothoracic
appendages much resembling miniature wings, and which especially suggest the
appearance assumed by the anterior pair (tegmina) in existing Phasmidw ‘There
is some evidence in favour of the view that they were articulated, and they exhibit
what appears to be a trace of venation. Brongniart concludes that in still earlier
strata, insects with six wings will be discovered, or rather insects with six of the
tracheal yills sutticiently developed to serve as parachutes. Of these, the two
posterior pair developed into the wings as we know them, while the anterior pair
degenerated, some of the Carboniferous insects presenting us with a stage in
which degeneration had taken place but was not complete.

One very important character was, as I have already pointed out, the enormous
size reached by insects in this distant period. This was true of the whole known
fauna as compared with existing species, but it was especially the case with the
Protodonata, some of these giant dragon-flies measuring over two feet in the
expanse of the wings.

As regards the habits of life and metamorphoses, Brongniart concludes that
some species of Protoephemeride, Protoperlidw, &c., obtained their food in an
aquatic larval stage, and did not require it when mature. He concludes that
the Protodonata fed on other animals, like our dragon-flies ; that the Paleacridiides
were herbivorous like our locusts and grasshoppers. the Protolocustide herbivorous
and animal feeders like our green grasshoppers, the Paleoblattidee omnivorous
like our cockroaches. The Homoptera, too, had elongated sucking mouth-parts
like the existing species. It is known that in Carboniferous times there was a lake
with rivers entering it, at Commentry. From their great resemblance to living
forms of known habits, it is probable that the majority of these insects lived near
the water and their larve in it. ;

When we look at this most important piece of research as a whole, we cannot
fail to be struck with the small advance in insect structure which has taken place
since Varboniferous times. All the great questions of metamorphosis, and of the
structures peculiar to insects, appear to have been very much in the position
in which they are to-day. It is indeed probable enough that the Orders which
zoologists have always recognised as comparatively modern and specialised, such
as the Lepidoptera, Coleoptera, and Hymenoptera, had not come into existence.
But as regards the emergence of the Class from a single primitive group, as regards
its approximation towards the Myriapods, which lived at the same ‘time, and of
both towards their ancestor Peripatus, we learn absolutely nothing. All we can
say is that there is evidence for the evolution of the most modern and specialised
members of the Class, and some slight evolution in the rest. Such evolution is of
importance as giving us some vague conception of the rate at which the process
trayels in this division of the Arthropoda. If we look upon development as
a series of paths which, by successively uniting, at length meet in a common point,
then some conception of the position of that distant centre may be gained by
measuring the angle of divergence and finding the number of unions which occur
in a given length. In this case, the amount of approximation and union shown in

TRANSACTIONS OF SECTION D. 19

the interval between the Carboniferous Period and the present day is relatively
so small that it would require to be multiplied many times before we could
expect the lines to meet in the common point, the ancestor of insects, to
say nothing of the far more distant past, in which the Tracheate Arthropods
met in an ancestor presenting many resemblances to Peripatus. But it must not
be forgotten that all this vast undetined period is required for the history of one of
the two grades of one of the three branches of the whole Phylum.

Turning now to the brief consideration of the second grade of Arthropods,
distinguished from the first grade by the absence of antenna, the Trilobites are
probably the nearest approach to an ancestral form met with in the fossil state.
Now that the possession of true antenne is certain, it is reasonable to suppose that
the Trilobites represent an early Class of the Aceratous branch which had not yet
become Aceratous. They are thus of the deepest interest in helping us to under-
stand the origin of the antennaless branch, not by the ancestral absence, but by the
loss of true antenne which formerly existed in the group. But the Trilobites did
not themselves originate the other Olasses, at any rate during Paleozoic times.
They represent a large and dominant Class, presenting more of the characters of the
common ancestor than the other Classes; but the latter had diverged and had
become distinct long before the earliest fossiliferous rocks; for we find well-marked
representatives of the Crustacea in Cambrian, and of the Arachnida in Silurian
strata. The Trilobites, moreover, appear in the Cambrian with many distinct and
very different forms, contained in upwards of forty genera, so that we are clearly
very far from the origin of the group.

Of the lower group of Crustacea, the Entomostraca, the Cirripedes are repre-
sented by two genera in the Silurian, the Ostracodes by four genera in the Cambrian
and over twenty in the Silurian; of these latter two genera, Cythere and Bairdia,
continue right through the fossiliferous series and exist at the present day.
Remains of Phyllopods are more scanty, but can be traced in the Devonian and
Carboniferous rocks. The early appearance of the Cirripedes is of especial interest,
inasmuch as the fixed condition of these forms in the mature state is certainly not
primitive, and yet, nevertheless, appears in the earliest representatives.

The higher group, the Malacostraca, are represented by many genera of Phyl-
locarida in the Silurian and Devonian, and two in the Cambrian. These also
afford a good example of the imperfection of the record, inasmuch as no traces of
the group are to be found between the Carboniferous and our existing fauna in
which it is represented by the genus Nebalia, The Phyllocarida are recognised as
the ancestors of the higher Malacostraca, and yet these latter already existed—
in small numbers, it is true—side by side with the Phyllocarida in the Devonian.
The evolution of the one into the other must have been much earlier. Here, as in
the Arthropoda, we have evidence of progressive evolution among the highest
groups of the Class, as we see in the comparatively late development of the Brachyura
as compared with the Macrura, We find no trace of the origin of the Class, or of
the larger groups into which it is divided, or, indeed, of the older among the small
groupings into families and genera.'

Of the Arachnida, although some of the most wonderful examples of persistent
types are to be found in this class, but little can be said. Merely to state the
bare fact that three kinds of scorpion are found in the Silurian, two Pedipalpi,
eight scorpions, and two spiders in the Carboniferous, is sufficient to show that the

eriod computed by geologists must be immensely extended to account for the

evelopment of this Class alone, inasmuch as it existed in a highly specialised
condition almost at the beginning of the fossiliferous series; while, as regards
so extraordinarily complex an animal as a scorpion, nothing apparent in the way of
progressive development has happened since. Professor Lankester has, however,
pointed out to me that the Silurian scorpions possessed heavier limbs than those of
existing species, and this is a point in favour of their having been aquatic, like
their near relation, Limulus. it so, it is probable that they possessed external

1 For an account of the evolution of the Crustacea see the Presidential Addresses
to the Geological Society in 1895 and 1896 by Dr. Henry Woodward.

20 REPORT—1896.

gills, not yet inverted to form the lung-hook. The Merostomata are of course a
Paleozoic group, and reach their highest known development at their first appear-
ance in the Silurian; since then they have done nothing but disappear gradually,
leaving the single genus Limulus, unmodified since its first appearance in tha
Trias, to represent them. It is impossible to find clearer evidence of the decline
rather than the rise of a group. No progressive development, but a gradual cr
rapid extinction, and consequent reduction in the number of genera and species, is
a summary of the record of the fossiliferous rocks as regards this group and many
others, such as the Trilobites, the Brachiopods, and the Nautilide. All these
groups begin with many forms in the oldest fossiliferous rocks, and three of them
have left genera practically unchanged from their first appearance to the present
day. What must have been the time reyuired to carry through the vast amount
of structural change implied in the origin of these persistent types and the groups
to which they belong—a period so extended that the interval between the oldest
Paleozoic rocks and the present day supplies no measurable unit ?

But I am digressing ben the Appendiculate Phylum. We have seen that the
fossil record is unusually complete as regards two Classes in each grade of the
Arthropod branch, but that these Olasses were well developed and flourishing in
Palzeozoic times. The only evidence of progressive evolution is in the development
of the highest orders and families of the Classes. Of the origin of the Classes
nothing is told, and we can hardly escape the conclusion that for the development
of the Arthropod branches from a common Cheetopod-like ancestor, and for the
further development of the Classes of each branch, a period many times the length
of the fossiliferous series is required, judging from the insignificant amount of
development which has taken place during the formation of this series.

It is impossible to consider the other Coelomate Phyla as I have done the
Appendiculata. I can only briefly state the conclusions to which we are led.

As regards the Molluscan Phylum, the evidence is perhaps even stronger than
in the Appendiculata. Representatives of the whole of the Classes are, it is believed,
found in the Cambrian or Lower Silurian. The Pteropods are generally admitted
to be a recent modification of the Gastropods, and yet, if the fossils described in the
genera Conularia, Hyolithes, Pterotheca, &c. are true Pteropods, as they are
eee to be, they occur in the Cambrian and Silurian strata, while the group
of Gastropods from which they almost certainly arose, the Bullide, are not known

before the Trias. Furthermore, the forms which are clearly the oldest of the
Pteropods—Limacina and Spiriales—are not known before the beginning of the
“Tertiary Period. Hither there is a mistake in the identification of the Paleozoic
fossils as Pteropods, or the record is even more incomplete than usual, and the
most Ssacialiied of all Molluscan groups had been formed before the date of the
earliest fossiliferous rocks. If this should hereafter be disproved, there can be no
doubt about the early appearance of the Molluscan Classes, and that it is the irony
of an incomplete record which places the Cephalopods and Gastropods in the
Cambrian and the far more ancestral Chiton no et than the Silurian. Through-
out the fossiliferous series the older families of Gastropods and Lamellibranchs are
followed by numerous other families, which were doubtless derived from them ;
new and higher groups of Cephalopods were developed, and, with the older groups,
either persisted until the present time or became extinct. But in all this splitting
up of the Classes into groups of not widely different morphological value, there is
very little progressive modification, and, talcin such changes in such a period as
our unit for the determination of the time which was necessary for the origin of
the Classes from a form like Chiton, we are led to the same conclusion as that
which followed from the consideration of the Appendiculata, viz. that the fossi-
liferous series would have to be multiplied peelesn | AP in order to provide it.

Of the Phylum Gephyrea, I will only mention the Brachiopods, which are
found in immense profusion in the early Paleozoic rocks and which have occupied
the subsequent time in becoming less dominant and important. So far from

_helping us to clear up the mystery which surrounds the origin of the Class, the
earliest forms are quite as specialised as those living now, and, some of them (Lingula

TRANSACTIONS OF SECTION D. 21

Discina) even generically identical. The demand for time to originate the group
is quite as grasping as that of the others we have been considering.

All the Classes of Echinoderma, except the Holothurians, which do not possess
a structure fayourable for fossilisation, are found early in the Palsozoic rocks,
and many ofthem inthe Cambrian. Although these early forms are very different
from those which succeeded them in the later geological periods, they do not possess
a structure which can be recognised as in any way rimitive or ancestral. The
Eehinoderma are the most distinct and separate of all the Ccelomate Phyla,
and they were apparently equally distinct and separate at the beginning of the
fossiliferous series.

In concluding this imperfect attempt to deal with a very vast subject in a very
short time, I will remind you that we were led to conclude that the evolution of
the ancestor of each of the higher animal Phyla, probably occupied a very long
period, perhaps as long as that required for the evolution which subsequently
paracel within the Phylum. But the consideration of the higher Phyla
which occur fossil, except the Vertebrata, leads to the irresistible conclusion that
the whole period in which the fossiliferous rocks were laid down must be
multiplied several times for this later history alone. The period thus obtained
requires to be again increased, and perhaps doubled, for the earlier history.

In the preparation of the latter part of this address I have largely consulted
Zittel’s great work. I wish also to express my thanks to my friend Professor
Lankester, whom I have consulted on many of the details, as well as the general plan
which has been adopted.

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LIVERPOOL, 1896.

ADDRESS

GEOGRAPHICAL SECTION,

Masor DARWIN, Sec. R.G.S.,
PRESIDENT OF THE SECTION,

In reviewing the record of geographical work during the past year, all other
performances pale in comparison with the feat accomplished by Nansen. It is not
merely that he has gone considerably nearer the North Pole than any other
explorer, it is not only that he has made one of the most courageous expeditions
ever recorded, but he has established the truth of his theory of Polar currents,
and has brought back a mass of valuable scientific information. When Nansen
comes to England I am certain that we shall give him a reception which will prove
how much we admire the heroism of this brave Norwegian.

Besides the news of this most remarkable achievement, the results of a con-
siderable amount of useful exploratory work have been published since the British
Association met last at Ipswich. With regard to other Arctic Expeditions, we
have had the account of Lieutenant Peary’s third season in Northern Greenland,
from which place he came back in September last, and to which he has again
returned, though without the intention of passing another winter there. In
October the ‘ Windward’ brought home more ample information as to the progress
of the Jackson-Harmsworth Expedition than that communicated by telegram to the
Association at Ipswich, and on her return from her remarkably rapid voyage this sum-
mer she brought back the record of another year. As to geographical work in Asia,
Mr. and Mrs. Littledale returned safely from their explorations of the little known
parts of Tibet; the Pamir Boundary Commission, under Colonel Holdich, has
collected a great deal of accurate topographical information in the course of its
labours ; Dr. Sven Hedin continues his important researches in Turkestan ; and
the Royal Geographical Society was glad to welcome Prince Henry of Orleans
when he came to tell us about his journey near the sources of the Irrawaddy. As
to Africa, the most important additions to our knowledge of that continent are
due to the French surveyors, who have accurately mapped the recently discovered
series of lakes in the neighbourhood of Timbuktu, Lake Faguibine, the largest,
being found to be 68 miles in length; Dr. Donaldson Smith has filled up some
large blanks in the map of Somaliland; and Mr. and Mrs. Theodore Bent have
investigated some interesting remains of ancient gold workings inland of the Red
Sea. In other parts of the world less has been done, because there is less to do,
Mr. Fitzgerald has proved for the first time the practicable character of a pass
across the Southern Alps, thus supplementing the excellent work of Mr. Harper
and other pioneers of the New Zealand Alpine Club; and Sir W. M. Conway has
commenced a systematic exploration of the interior of Spitzbergen, a region to
which the attention of several other geographers is also directed.

E

2 REPORT—1896. a.

It is impossible in such a brief sketch to enumerate even the leading events of
the geographical year, but what I have said is enough to remind us of the great
amount of valuable and useful work which is being done in many quarters of the
world. It is true that if we compare this record with the record of years gone by,
we find a marked difference. Then, there was always some great geographical
problem to be attacked ; the sources of the Nile had to be discovered ; the course
of the Niger had to be traced; and the great white patches on our maps stimulated
the imagination of explorers with the thought of all sorts of possibilities. Now,
though there is much to be learned, vet, with the exception of the Poles, the work
will consist in filling in the details of the picture, the general outlines being all
drawn for us already. Personally I cannot help feeling a completely unreasoning
regret that we have almost passed out of the heroie period of geography. What-
eyer the future may have in store for us, it can never give us another Columbus,
another Magellan, or another Livingstone. The geographical discoverers of the
future will win their fame in a more prosaic fashion, though their work may in
reality be of even greater service to mankind. There are now few places in the
world where the outline of the main topographical features is unknown ; but, on the
other hand, there are vast districts not yet thoroughly examined. And, in examin-
ing these more or less known localities, geographers must take a far wider view
than heretofore of their methods of study in order to accommodate themselves to
modern conditions. ; ;

But even if we confine our attention to the older and more narrow field of
geography, it will be seen that there is still an immense amount of work to be
done. We have been filling in the map of Africa during recent years with
extraordinary rapidity, but yet that map is likely to remain in a very unsatisfactory
condition for a long time to come. Englishmen and other Europeans have always
shown themselves to be ready to risk their lives in exploring unknown regions, but
we have yet to see how Sans they will undertake the plodding work of recordin
topographical details when little renown is to be won by their efforts. It kone
be one of the objects of geographical societies to educate the public to recognise
the importance of this work, and General Chapman deserves great credit for bring-
ing the matter before the International Congress last year in such a prominent
manner. He confined himself to four main recommendations. (1) The extension
of accurate topographical surveys in regions likely to be settled by Europeans.
(2) The encouragement of travellers to sketch areas rather than routes. (3) The
study of astronomical observations already taken in the unsurveyed parts of Africa
in a systematic manner, and the publication of the results. (4) The accurate
determination of the latitude and longitude of many important places in unsurveyed
Africa. I am certain that all geographers are in hearty accord with General
Chapman in his views, and it is, perhaps, by continually bringing this matter before
the public, that we shall best help this movement forward.

Not only do we want a more accurate filling in of the picture, but we have yet
to learn to read its lessons aright. The past cannot be understood, and still less
can the future be predicted, without a wider conception of geographical facts.
Look, for example, at the European Colonies on the West Coast of Africa. Here
we find that there have been Portuguese settlements on the Gold Coast since the
year 1471, the French possibly having been established there at an even earlier
date ; whilst we English, who pride ourselves on our go-ahead character, have had
trading fuctories on the Coast since 1667. I have here a map showing the state of
our geographical knowledge in 1815. Why was it that Europeans have never,
broadly speaking, pushed into the interior from their base on the coast, which they
had oceupied for so many centuries? That they had not done so, at least to any
purpose, is proved by this map. Why had four centuries of contact with Europeans
done so little even for geographical knowledge at that time? The answer to this
question may be said to be mainly historical; but the history of our African
Colonies can never be understood without a study of the distribution of the dense
belt of unhealthy forest along the shore; of the distribution of the different types
of native inhabitants; and of the courses of the navigable rivers, all strictly geo-

graphical considerations.

: -
a TRANSACTIONS OF SECTION E. 3

Geography is the study of distribution, and early in that study we must be
struck with the correlation of these different distributions. If we take a map of
Africa, and mark on it all the areas within the tropics covered with dense forest
or scrub, we shall find we have drawn a map showing accurately the distribution
of the worst types of malarial fever ; and that we have also indicated with some
approach to accuracy—with, however, notable exceptions—the habitat of the lowest

of mankind. These are the facts which give the key to understanding why
the progress of European colonisation on the West Coast has been so slow.

Along the coast of the Gulf of Guinea we find settlements of Europeans at
more or less distant intervals. All along, or nearly all along this same coast, we
find a wide belt of fever-stricken forest, fairly thickly inhabited by uncivilised
Negro and Bantu tribes. Inside this belt of forest the country rises in altitude,
and becomes more open, whilst at the same time there is a distinct improvement
in the type of native ; and the more we proceed inland, the more marked does this
improvement become. There appear in fact to have been a number of waves of
advancing civilisation, each one pressing the one in front of it towards these
inhospitable forest belts. Near the coast the lowest type of negro is, generally
speaking, to be found; then, as the more open country is reached, higher types of
negroes are encountered—for example, the Mandingoes of the Senegal region are
distinctly higher than the Jolas inhabiting the mouths of the Gambia; and the
Hausas of the Sokoto Empire are vastly superior to the cannibals of the Oil Rivers.
In both these cases the higher types are probably not pure negroes, but have Fulah,
Berber, or Arab blood in their veins; for we see, in the case of the Fulahs, how
they become absorbed into the race they are conquering; near the Senegal River
they are comparatively light in colour, but in Adamawa they are hardly to be dis-
tinguished by their features from the negroes they despise. Thus the process
appears to have been a double one; the higher race driving some of the lower
aboriginal tribes before them out of the better lands, and, at the same time, raising
other tribes by means of an admixture of better blood. These waves of advancing
civilisation seem to have advanced from the north and east, for the more we pene-
trate in these directions, the higher is the type of inhabitant met with, until at
last we reach the pure Berbers and the pure Arabs. Thus there are two civilising
influences visible in this part of Africa; one coming from the north and east—a
Mahommedan advance—which keeps beating up against this forest belt and occa-
sionally breaking into it; the other, a Christian movement, which, until the
middle of this century, was brought to a dead halt by this same obstacle. The
map of Africa, showing the state of geographical knowledge in 1815, makes it clear
that, except in a few cases where rivers helped travellers through these malarial
regions, nothing was known about the interior. No doubt much has been done
since those days, but this barrier still remains the great impediment to progress
from the West Coast ; and those who desire our influence to spread more effec-
tively into the interior must wish to see some means of overcoming this obstacle.
On the East Coast of Africa the conditions are somewhat different, as there is
comparatively little dense forest there; but the districts near that coast are also
usually unhealthy, and how to cross those malarial regions quickly into the healthy
or less unhealthy interior is the most important problem connected with the
development of tropical Africa.

Other influences have been at work, no doubt, in checking our progress from
the West Coast. In old days, the European possessions in these districts were
mere depots for the export of slaves. As the white residents could not hope to
compete with the natives in the actual work of catching these unfortunate creatures,
and as the lower the type the more easily were they caught, as a rule, there was
no reason whatever for attempting to penetrate into the interior, where the higher
types are met with. But, though this export trade in human beings is now no
longer an impediment to progress, the slave trade in the interior still helps to bar
the way. When the forest belt is passed, we now come, generally speaking, to the
Ime of demarcation between the Mahommedan and the Pagan tribes, and here slave
catching is generally rife; when it is so, the constant raids of the Mahommedan
chiefs keep these border districts in a state of unrest, which in every way tends to

A REPORT—1896.

impede progress. Thus a mere advance to the higher inland regions will not b
any means solve all our difficulties; but it will greatly lessen them; and it is
universally admitted that the more communication with the interior is facilitated,
the more easy will it be to suppress this terrible traflic in human beings. By the
General Act of the Brussels Anti-Slavery Conference of 1890-91, it was agreed by
the assembled delegates that the construction of roads, and, in particular, of rail-
ways, connecting the advanced stations with the coast, and permitting easy access
to the inland waters, and to the upper courses of rivers, was one of the most effec-
tive means of counteracting the slave trade in the interior. Here, then, we have
the most formal admission which could be given of the necessity of opening up
main trunk lines of communication into the interior.

But not only does geographical knowledge help to demonstrate the necessity of
improving the means of communication between the coast and the interior, but it
helps us to decide where it is wise to make our first efforts in this direction. In
the first place, it is essential to note that if the Continent of Africa is compared
with other Continents, its general poverty is clearly seen. Mr. Keltie, in his excel-
lent work on the Partition of Africa, tells us that ‘at present (1895) it is estimated
that the total exports of the whole of Central Africa by the east and west coast do
not amount to more than 20,000,000/. sterling annually.’ For the purposes of com-
parison it may be mentioned that the export trade of India is between sixty and
seventy millions sterling annually, and that India is only about one-seventh or
one-eighth of the area of the whole of Africa. On the other hand, the trade of
India has been increasing by leaps and bounds, largely in consequence of the
country being opened out by railways, and there is every reason to hope that some-
what similar results would occur in Africa under similar circumstances, though
the lower civilization of the people would prevent the harvest being so quickly
reaped. But, however it may be as to the future, the present poverty of Africa is
enough to demonstrate the necessity of pushing ahead cautiously and steadily, and
of doing so in the most economical manner possible.

M. Decle, in an interesting paper, read before the International Geographical
Congress in London last year, strongly advocated the construction of cheap roads
for use by the natives, taking precautions to prevent any traffic in slaves along
them, His suggestions are well worthy of consideration ; but the cost of transport
along any road would, I should have thought, soon have eaten up any profits on
the import or export trade to or from Africa. What must be done in the first
instance is to utilise to the utmost all the natural lines of communication which
require little or noexpenditure to render them serviceable; in fact, to turn our
attention at first to the rivers and to the lakes. I have already pointed out that
the early maps of Africa prove that the rivers have almost invariably been the first
means of communication with the interior, and until this continent is rich enough
to support an extensive railway system, we must rely largely on the waterways as
means of transport.

Tt may be as well here to remark that geographical knowledge is often required
in order to control the imagination. I do not know why it is, but almost everyone
will admit that if he sees a lake of considerable size depicted on a map, he immedi-
ately feels a desire to visit or possess that locality in preference to others. A lake
may be of far less commercial value than an equal length of thoroughly navigable
river, and yet it will always appear more attractive. ook at the way in which
the English, the French, and the Germans are all pressing forward to Lake Chad ;
and yet Lake Chad is in reality not much more than a huge swamp, and, in all pro-
bability, it is excessively unhealthy. Again, it is probable that the Albert Nyanza
will prove to be of comparatively small value, because the mountains come down so
clese to its shores. Of course, the great lakes form an immensely important feature
in African geography, but we must judge their commercial value rationally, and
without the bias of imagination. 4

To develop the traffic along the rivers and on the lakes is the first stage in the
commercial evolution of a continent like Africa. But it cannot carry us very
far. Africa is badly supplied with navigable rivers, chiefly as a natural result
of the general formation of the land. The continent consists, broadly speaking,

TRANSACTIONS OF SECTION Ex 5

of a huge plateau, and the rivers flowing off this plateau are obstructed by
cataracts in exactly the places where we most want to use them—that is, when
approaching the coasts. The second stage in the commercial evolution will
therefore be the construction of railways with the view of supplementing this
river traffic. Finally, no doubt, a further stage will be reached, when railways
will cut out the rivers altogether; for few of the navigable rivers are really well
suited to serve as lines of communication. ‘This last stage is, however, so far off
that we may neglect it for the present; though it must be noted that there are
‘some parts of Africa where there are no navigable rivers, and where, if anything
is to be done, it must be entirely by means of railways.

Thus, as far as the immediate future is concerned, the points to which our
attention should be mainly directed are (1) the courses of the navigable parts of
the rivers, and (2) the routes most suitable for the construction of railways in
order to connect the navigable rivers and lakes with the coast. As to the
navigable rivers, little more remains to be discovered with regard to them, and
we can indicate the state of our geographical knowledge on this point with
sufficient accuracy for our purposes by means ofa map. Of course the commercial
value of a waterway depends greatly on the kind of boats which can be used, and
that point cannot well be indicated cartographically.

As to the railways, we must study the physical features of the country
through which the proposed lines of communication would pass. All the
obstacles on rival routes should be most carefully surveyed when considering
the construction of railways in an economical manner. Great mountain chains
are seldom met with in Africa, and from that point of view the continent is us a
whole remarkably free from difficulties. But drifting sand is often a serious
trouble, and that is met with commonly enough in many parts. Wide tracks of
rocky country also form serious impediments, both because of the cost of con-
struction, and also because the supply of water for the engines becomes a problem
not to be neglected. Such arid and sandy districts are of course thinly in-
habited, and we may therefore generally conclude that where the population is
scanty, there railway engineers will have special difficulties to face. On the
other hand, dense forests are also very unsuitable. We have not much ex-
perience to guide us, but it would appear probable that the initial expense of
clearing the forest, and the cost of maintenance, in perpetually battling against
the tropical vegetable growth. will be very heavy; for it will not do to allow the
line to be in constant danger of being blocked. ‘The dampness of the forest,
which will cause all woodwork and wooden sleepers to rot, will be no small
source of trouble, and the virulent malarial fevers, always met with where the
vegetation is very rank, will add immensely to the difficulty both of construction
and of maintenance. The health of the European employés will be a most serious
question in considering the construction of railways in all parts of tropical Africa,
for the turning up of the soil is the most certain of all methods of causing an
outbreak of malarial fever; and the evil results would be most severely felt in
constructing ordinary railways in dense forests. In making the short Senegal
railway, where the climate is healthier than in many of the districts further
south, the mortality was very great. Perhaps we shall have to modify our usual
methods of construction so as to mitigate this danger, and, in connection with
this subject, I may perhaps mention that the Lartigue system seems to be specially
worthy of consideration—a system by which the train is carried on a single ele-
vated rail. This is perhaps travelling rather wide of the mark of ordinary geo-
graphical studies, but it illustrates the necessity of a thorough examination of
the environment before we try to transplant our own methods to other climes.

We may, however, safely conclude that we must as far as possible avoid
both dense forests and sandy and rocky wastes in the construction of our first
railways.

Then, as to the lines of communication, considered as a whole, rail and river
combined, we must obviously, if any capital is to be expended, make them in the
directions most likely to secure a profitable traffic. In considering this part of the
question, it will be seen that there are several different problems to be discussed :

E2

6 REPORT—1896.

(1) trade with the existing population in their present condition; (2) trade with’

the native inhabitants when their countries have been further developed with the —

aid of European supervision ; and (3) trade with actual colonies of European
settlers. To many minds the last of these problems will appear to be the most
important, and in the end it may prove to be so. But the time at my disposal
compels me to limit myself to the consideration of trade with the existing native
races within the tropics, with only an occasional reference to the influence of white
residents. We must, no doubt, carefully consider which are the localities most
likely to attract those Europeans who go to Africa with the view of establishing
commercial intercourse and commercial methods in the interior ; and there can be
no doubt that considerations of health will play a prominent part in deciding
this point. Moreover, as the lowest types of natives have few wants, the more
primitive the inhabitants of the districts opened up, the less will be the probability
of a profitable trade being established. Por both these reasons the coast districts
are not likely in the end to be as good a field for commercial enterprise as the
higher lands in the interior; for the more we recede from the coast, the less
unhealthy the country becomes, and the more often do we find traces of native
civilisation. To put it simply, we must consider both the density of the population
and the class of inhabitant in the districts proposed to be opened up. Of course,
the exact nature of the products likely to be exported, and the probability of
demands for European goods arising amongst the natives of different districts, are
vitally important considerations in estimating the profits of any proposed line of
railway ; but to discuss such problems in commercial geography at length would
open up too wide a field on an occasion like this. .

If the importance of considering the density of the population in the different
districts in such a preliminary survey is admitted, we may then simplify our
inquiry by declining to discuss any lines of communication intended to open up
regions where the population falls below some fixed minimum—whatever we may
like to decide on. Of course, the question of the greater or less probability of a
locality attracting white temporary residents is very important, but unless there is
a native population ready to work on, there will be little done for many years to
come. Politically it may or may not be right to open up new districts by railways
for the sake of finding outlets for our home or our Indian population ; but here I
am considering the best lines for the development of commerce, taking things as
they are. What then shall be this minimum of population? The population of
Bengal is 470 per square mile; of india, as a whole, about 180; and of the United
States, about 21 or 22. If it is remembered that the inhabitants of the United
States are, per head, vastly more trade-producing than the natives of Afriea, it will
be admitted that we may for the present exclude from our survey all districts in
which the population does not reach a minimum of 8 per square mile; it might be
right to put the minimum much higher than this. On the map now before you,
the uncoloured parts show where the density of population does not come up
to this minimum, and we can see at a glance how enormously this reduces the area
to be considered. The light pink indicates a population of from 8 to 32 per square
mile, and the darker pink a denser population than that. Of course, such a map,
in the very imperfect state of our knowledge, must be very inaccurate, as I am
sure the compiler would be the first to admit. On the same map are marked the
navigable a of rivers. I should like to have shown the dense forests also, but
the difficulty of giving them with any approach to correctness is at present
insuperable.

lere, then, is the kind of map we want in order to consider the broad outline
of the questions connected with the advisability of attempting to push lines of
communication into the interior. The problem is how to connect the inland parts
of Africa, which are coloured pink on this map, with the coast, by practicable lines
of communications, at the least cost, with the least amount of dense forest to be
traversed, and, in the case of railways, whilst avoiding as far as possible all thinly
populated districts.

It is of course quite impossible here to discuss all the great routes into the
interior, and I should like to deyote the remaining time at my disposal to the

TRANSACTIONS OF SECTION E. 7

consideration of this problem as far as a few of the most important districts are
concerned, confining myself, as I have said, to trade with existing native races
within the tropics. Taking the East Coast first, and beginning at the north, the
first region suthciently populous to attract our attention is the Valley of the Nile,
and parts of the Central Sudan. Wadai, Darfur, and Kordofan are but scantily
inhabited, according to our map, and this is probably the case now that the
Khalifa has so devastated these districts; but, without doubt, much of this country
could support a teeming population, and is capable of great commercial develop-
ment. The Dahiec-Ghbeal districts are especially attractive, being fertile and
better watered than the somewhat arid regions further north. These remarks
remind me how difficult it is at this moment to touch on this subject without
trenching on politics. Few will deny that the sooner this region is connected
with the civilised world the better, and it is only as to the method of opening it
up, and as to who is to undertake the work, that burning political questions will
arise. The geographical problems connected with the lines of communication to
the interior can be considered whilst leaving these two points quite on one side.

A glance at the map reminds us of the well-known fact that, below Berber,
the Nile is interrupted by cataracts for several hundred miles, whilst above that
town there is a navigable water-way at high Nile until the Fola rapids are reached,
a distance of about 1,400 miles, not to mention the 400 to 600 miles of the Blue
Nile and the Bahr-el-Gazal, which are also navigable. The importance of a rail-
way from Suakin to Berber is thus at once evident, and there is perhaps only one
other place in Africa where an equal expenditure would open up such a large tract
of country to European trade. This route, however, is not free from difficulties.
Suakin is hot and unhealthy. Then the railway, about 260 miles in length, passes
over uninhabited-or thinly inhabited districts the whole way. Though the hills
over which it would pass are of no great height, the highest part of the track
being under 3,000 feet above the sea, it is often said that the desert to be
traversed would add greatly to the difficulty of construction. According to
Lieut.-Colonel Watson, R.E., however, these difficulties have been greatly exag-
gerated, for the water supply would give no great trouble. The sixth cataract,
between Meterma and Khartum, would make navigation for commercial purposes
impossible when the waters are low; it is probable that this impediment could be
overcome by erecting locks, but it is impossible to estimate the cost of such works.
Then, again, the Nile above Khartum is much obstructed by floating grass or sudd,
making navigation at times almost impossible ; but it was Gordon's opinion that a
line of steamers on the river, even if running at rare intervals, would keep the
course of the stream clear; this, however, remains to be proved.

If the canalisation of the sixth cataract should prove to be too costly an under-
taking, then it would be most advisable to carry on the railway beyond that
obstacle. This might be done by prolonging the line along the banks of the Nile,
or by adopting an entirely different route from Suakin through Kassala. I hope
we shall hear something from Sir Charles Wilson as to the relative merits of
these proposals during the course of our proceedings. Proposals have also been
made for connecting the Nile with other ports on the Red Sea, and all of these
suggestions should be carefully examined before a decision is made as to the exact
route to be adopted. But in any case, considering the matter merely from a
geographical standpoint, and putting politics on one side—a very large omission
in the case of the Sudan—it would appear that one or other of these routes
should be one of the very first to be constructed in all Africa.

Passing further south, it is obvious from the configuration of the shore, and
from the distribution of the population, that the lines of communication next to
be considered are those leading to the Victoria Nyanza, and on to the regions lying
north and west of the lake.

Two routes for railways from the coast to the Victoria Nyanza have been pro-
posed, one running through the British and the other through the German sphere
of influence. Looking at the matter from a strietly geographical point of view,
there is perhaps hardly sufficient information to mar us to judge of the relative

merits of the two proposals, Both run through an unhealthy coast zone, and

8 REPORT—1896.

* .
both traverse thinly inhabited districts until the lake is reached. The German
route, as origivally proposed, would be the shorter of the two; but there is some
reason to think that the British line will open up more country east of the lake,
which will be suitable for prolonged residence by white men. Sir John Kirk, in
discussing the question of the possible colonisation of tropical Africa by Europeans,
said: ‘These uplands vary from 5,000 to 7,000 feet in height, the climate is cool,
and, as far as known, very healthy for Europeans. This district is separated from
the coast by the usual unhealthy zone, which, however, is narrower than elsewhere
on the African littoral, Between the coast zone and the highlands stretches a
barren belt of country, which attains a maximum width of nearly 200 miles. The
rise is gradual, and throughout the whole area to be crossed the climate is drier
and the malarial diseases are certainly much less frequent and less severe than in
the regions further south.’ These very advantages, however, may have to be
paid for by the greater difficulty of railway construction. Putting aside future
prospects, the map shows that the populous region to the west of the lake makes
either of these proposed lines well worthy of consideration, though it would
perhaps be rash to predict how soon the commerce along them would pay for the
interest on the capital expended. What will be the fate of the German project I
do not know, but we may prophecy with some contidence that the British line, the
construction of which has been commenced, will be completed sooner or later.

The two lines of communication we have disecussed—the Suakin and the Victoria
Nyanza routes—are intended to supply the wants of widely separated districts; but,
looking to a more distant future, they must sooner or later come into competition
one with the other, in attracting trade from the Central Sudan. Before this can
occur, communication by steamboat and by railway must be opened up between the
coast and the navigable Nile by both routes. This will necessitate a railway being
constructed, not only to the Victoria Nyanza, but also from that lake, or round it, to
the Albert Nyanza ; and, as the Nile is rendered unnavigable by cataracts about Du-
file, and as the navigation is difficult between Dutile and Lado, here also a railway
would be necessary in order to complete the chain of steam communication with
the coast. If goods were brought across the Victoria Nv anza by steamer, and taken
down the Nile in the same manner from the Albert Nyanza to Dutile, this route
would necessitate bulk being broken six times before the merchandise was under way
on the Nile; by the Suakin route, on the other hand, bulk would only have to be
broken twice, provided the sixth cataract were rendered navigable. Thus, if this
latter difficulty can be overcome, and if the sudd on the Nile is not found to
impede navigation very much, this Nyanza route will certainly not compete with
the Suakin route for any trade on the banks of the navigable Nile until a railway
is made from the coast to Lido, a distance of over 800 miles as the crow flies, and
certainly over 1,000 miles by rail. It must be remembered also that the Nyanza
route passes over mountains 8,700 feet above the sea; that the train will have to
mount, in all, nearly 13,000 feet in the course of its journey from the coast; and
that a difficult gorge has to be crossed to the eastward of the Victoria Nyanza.
From these facts we may conclude that it will be a very long time before the
Nyanza route will draw any trade from the Central Sudan.

The line through the British sphere of influence runs to the northern end of
Victoria Nyanza, but from Mr. Vandaleur's recent expedition into these regions we
learn that a shorter route, striking the eastern shore of the lake, is under considera-
tion. To lessen the expense of construction would be a great boon, but if we look
to the more ambitious schemes for the future, something may he said in favour of
the original proposal as being better adapted to form part of a line of railway
reaching the navigable Nile. j

With regard to the comparison between the German and British routes to the
Victoria Nyanza, the latest accounts seem to imply that the Germans have prac-
tically decided on a line from the coast to Ujiji, with a branch from Tabora to the
Victoria Nyanza. ‘This would be a most valuable line of communication ; but it
seems a pity that capital should be expended in competitive routes when there are
so many other directions in which it is desirable to open up the continent. If the
Germans wish to launch out on great railway projects in Africa, let them make a

TRANSACTIONS OF SECTION E. 9

line from the south end of Lake Tanganyika to the northern end of Lake Nyasa,
and thence on to the coast; they would thus open up a vast extent of territory,
and Baron von Schele tells us that a particularly easy route can be found from
Kilva to the lake. Such a line of communication, especially if eventually con-
nected with the Victoria Nyanza to the north, would be more valuable than any
other line in Africa in putting an end to the slave trade, as it would make it pos-
sible to erect a great barrier, as it were, running north and south across the roads
traversed by the slave traders.

A line through German territory connecting Lake Nyasa with the sea would, no
doubt, come into competition with the route connecting the southern end of that
lake with the Zambesi, and thus with the coast. The mouths of the Zambesi,
though they are passable, will always present some impediment to commerce. But
after entering the river navigation is not obstructed until the Murchison Rapids on
the Shiré River arereached. Here there are at present sixty miles of portage to be
traversed, and this transit must be facilitated by the construction of a railway, if this
route is to be properly developed ; Mr. Scott Elliot tells us that 120 miles of railway,
from Chiromo to Matope, would be necessary for this purpose. Beyond this latter
point there isa good waterway to Lake Nyasa. Thus a comparatively short line of
railway would open up this lake to European commerce, and this route is likely to
be developed at a much earlier stage of the commercial evolution of Africa than the
one through German territory above suggested. It will be seen that these routes
connect fairly populous districts with the coast, and it must also be recollected
that the high plateau between Lake Nyasa and the Kafue River is one of the very
few regions in tropical Africa likely to attract white men as more or less perma-
nent residents.

Further south we come to the Zambesi River, which should, of course, be
utilised as far as possible. But this line of communication to the interior has
many faults. The difficulties to be met with at the mouths of the Zambesi have
already been alluded to. Then the whole valley is unhealthy, and white travellers
would prefer any route which would bring them on to high land more quickly.
Moreover the Kebrabasa rapids cause a serious break in the waterway, and, as the
river above that point is cake navigable for canoes, it is doubtful if it would ever
be worth making a railway for the sole purpose of connecting these two portions
of the river.

As the population of the upper Zambesi valley is considerable, and as the
country further from its banks is said to be likely to be attractive to white men,
there can be no doubt of the advisability of connecting it with the coast. This
naturally leads us to consider the Beira route, as a possible competitor with the
Zambesi. A sixty centimetre railway is now open from Fontesvyilla to Chimoio
(190 kilometres), and it is probable that during the course of the next two years
the construction of the railway will be completed from the port of Beira itself as
far as the territory of the Chartered Company. ‘This will form the first step in the
construction of a much better line of communication to the Upper Zambesi regions
than that afforded by the river itself. It is true that the gauge is very narrow, and
that the first part of the line passes through very unhealthy districts; but this line
will nevertheless be a most valuable addition to the existing means of penetrating
into the interior of the continent. It is needless to say that the object of this
railway is to open up communications with Mashonaland, not for the purposes now
suggested.

South of the Zambesi the map shows us that there are no regions in tropical
Africa where the density of the native population reaches the minimum of eight
per square mile. Here, however, we come to the gold fields, where there is
attractive force enough to draw white men in great numbers within the tropics,
and where, no doubt, some of the most important problems connected with railway
communications will have to be solved in the immediate future. But, for reasons of
‘time and space, I have limited myself to the discussion of districts within the tropics,
where trade with the existing native races is the object in view. The Beira
railway does not in reality come within the limits I have imposed on myself,

10 REPORT—1896. \= >

* —~
except as to its future development. Had time permitted, I should like to have —
discussed the route leading directly from the Cape to Mashonaland, its relative —
merits in comparison with the Beira railway, PLN to where the two will come
into competition one with the other. But I must pass on at once to consider the
main trunk routes from the West Coast leading into the interior of Africa.

Passing over those regions on the West Coast where railways would only be
commenced because of the probable settlement, temporary or permanent, of white
men—passing over, that is, the whole of the German sphere of influence—we first
come to more dense native populations near the coast towns of Benguela and
St. Paul de Loanda. The latter locality is the more hopeful of the two, accord-
ing to our map, and here we find that the Portuguese have already con-
structed a railway leading inland for 191 miles to close to Ambaca. The intention
of connecting this railway with Delagoa Bay was originally announced, and IT am
not aware to what extent this vast project has now been cut down, so as to bring
it within the region of practical proposals. A further length of 35 miles is, at all
events, being constructed, and 87 more miles have been surveyed. The Portuguese
appear to be very active at present in this district, as there are several other rail-
ways already under consideration ; one from Benguela to Bihe, of which 16 miles
is in operation, another from Mossamedes to the Huilla Plateau, and a third from
the Congo to the Zambesi. It is difficult to foretell what will be the outcome of
these schemes, but our population map is not very encouraging.

Next we come to the Congo, and here there is a grand opportunity of opening
up the interior of the continent. In going up this great stream from the coast we
first traverse about 150 miles of navigable waterway, and afterwards we come to
some 200 miles of cataracts, through which steamers cannot pass. Round this im-
pediment a railway is now being pushed, 189 kilometres of rails (117 miles) being
already laid. Then we enter Stanley Pool, and from this point we have open
before us—if Belgian estimates are to be accepted—7,000 miles of navigable water-
way. If this fact is correct, and if the population is accurately marked on our
map, then there is no eee in all Africa where 200 miles of railway may be ex-
pected to produce such marked results. The districts traversed are unhealthy,
and the natives are, generally speaking, of a low type; but in spite of these draw-
backs, which no doubt will delay progress considerably, we may confidently predict —
a grand future for this great natural route into the interior. ;

To the north of the Congo, the next great navigable waterway met with is the
Niger. Again, granting the correctness of the population map, it can be seen at a
glance that there is no area of equal size in all Africa so densely inhabited, and no
district where trade with the existing native population appears to offer greater
inducement to open up a commercial route into the interior. Luckily little has to
be done in this respect, for the Niger is navigable for light-draught steamers in the
full season as far as Rabba, about 550 miles from the sea; here the navigation
soon becomes obstructed by rocks, and at Wuru, about 70 miles further up the
river, the rapids are so unnavigable that even the light native canoes have to be
emptied before attempting a passage, and there are frequent upsets. From Wuru
the rapids extend to Wara, after which a stretch of clear and slow-running river
is met with. Above this, again, the Altona Rapids extend for a distance of 15
miles ; then 15 miles of navigable waterway, and then 20 miles more of rapids are
encountered. Yelo, the capital of Yauri, is situated on these latter cataracts, above
which the Middle Niger is navigable for a considerable length. The Binue is also
navigable in the floods for many miles, the limits being at present unknown ; part
of the year, however, it is quite impassable except for canoes. The trade with
the Western Sudan, which has been made possible by the opening up of this river,
is still only in its infancy, and to get the full benefit of this waterway a line of
railway ought to be carried on from Lokoja to Kano, the great commercial centre
of Hausaland; Mr. Robinson's recent journeys over this country, which we hope to
hear about at a later period of our proceedings, have served to confirm the impres-
sion that no great physical difficulties would be encountered. The political con-
dition of the country may, however, make the construction of this pei quite
impossible for the present; for here we are on the borderland between Mahom-

a

medanism and Paganism, where the slave trade always puts great impediments in
the path of progress, but where the same circumstances make it so eminently desir-
able to introduce a higher condition of civilisation. The only drawback to the
Niger as a line of communication to the Western Sudan is the terribly unhealthy
nature of the coast districts which have to be traversed. Any man, who finds a
means of combating the deadly diseases here met with, will be the greatest bene-
factor that Africa has ever had; but of such a discovery there are ‘but few signs
at present.

It is perhaps too soon to speculate as to the best means of opening a trade
route to Fradat and the more central parts of the Western Sudan; for we may be
sure that little will be done in this direction for years to come. Several com-
peting routes are possible. From the British sphere, we may try to extend our
communications eastward from the navigable parts of the Binue. The French,
on the other hand, may push northwards from the Ubangi; whilst, in a later
stage of commercial evolution, the best route of all may be found through
German terrritory, by pushing a railway from the shore in a direct line towards
Bagirmi and Wadai. To compare the relative merits of these trunk lines is
perhaps looking too far into the future, and traversing too much unknown
country, to make the discussion at all profitable.

Proceeding northwards, or rather westwards, along the coast we find ourselves
skirting the belt of dense forest already described as being the great obstacle to
advance in this part of Africa. Tt is to be hoped that this barrier will be pierced
in several places before long. Naturally we turn our attention to the different
spheres of British influence, and here we are glad to learn that there are several
railways being constructed or being considered, with a view to opening up the
interior,

At Lagos a careful survey of a railway running in the direction of Rabba has
been made, and the first section is to be commenced at once. To connect the
Niger with the coast in this way would require 240 miles of railway, but the
immediate objectives are the towns of Abeokuta and Ibadan, which are said to
contain more than a third of a million inhabitants between them. No doubt the
pero coast region makes such a line most desirable; but whether it would

e wise to push on at all quickly to the Niger, and thus to come into competition
with the steamboat traffic on that river, is a very different question.

Surveys have also been made for a railway to connect either Kormantain or
Apan on the Gold Coast with Insuaim, a town situated on a branch of the Prah.
It is believed that the local traffic will be sufficiently remunerative to justify the
construction of this line. But, looking to the further prolongation of this rail-
way into the interior, it appears possible that those who selected this route were
too much influenced by the desire to reach Kumasi, which is a political rather
than a commercial centre. According to the views I have been advocating to-day,
the main object of a railway in this quarter should be the crossing of the forest
belt, and if, as there is some reason to believe, that belt is exceptionally wide and
dense in this locality, the choice of Kumasi as a main point on the route will
have been an unfortunate selection. A little further south, nearer the banks of
the Volta, it is probable that more open land would be met with, and moreover
that river itself, which is navigable for steam launches from Ada to Akusi, would
be of use as a preliminary means of transport. It is to be hoped that the merits
of a line from Accra through Odumase will be considered before it is too late.

IT am now approaching the end of my brief survey of tropical Africa, for the best
method of opening communication between the Upper Niger and the coast is the
last subject shall touch on. With this object in view, the French have con-
structed a railway from Kayes, the head of steam navigation during high water,
on the Senegal to Bafulabé, with the intention of ultimately continuing the line
to Bamaku on the Niger Unexpected difficulties have been met with in the
construction of this railway, and, as the Senegal River between Kayes and St.
Louis is only navigable for about a quarter of the year, it would hardly appear as
if the selection of this route had been based on sound geographical information.
No doubt the French will find some other practicable way of connecting the Upper

TRANSACTIONS OF SECTION E. 11

12 REPORT—1896,

Niger with the coast, and surveys are already in progress with that object in
view. It may be worth mentioning that the Gambia is navigable as far as
Yarbutenda, and that it affords on the whole a better waterway than the Senegal ;
it is possible, therefore, that a railway from Yarbutenda to Bamaku might form a
better means of connecting the Niger with the coast, than the route the French
have selected.

At Sierra Leone a railway is now being constructed in a south-easterly
direction with a view of tapping the country at the back of Liberia. But here, as.
in the case of the Gambia route, political considerations are of paramount im-

ortance; for no doubt the best commercial route, geographically speaking, would

ave been a line run in a north-easterly direction to some convenient point on the
navigable part of the Upper Niger. such a railway were ever constructed, it
would connect the longest stretch of navigable waterway in this region with the
best harbour on the coast. But the fact that it would cross the Anglo-French
boundary is a complete bar to this project at present.

Proposals for connecting Algeria with the Upper Niger by rail have often been
discussed in the French press, the idea being to unite the somewhat divided parts
of the French sphere of influence by this means. If the views here sketched
forth as tu the necessity of selecting more or less populous districts for the first
opening up of lines of communication into the interior are at all correct, these

rojects would be simple madness. For many a year to come Algeria and the
Viger will be connected by sea far more efficiently than by any overland route,
and I feel sure that when the details of these plans are properly worked out we
shall not find the French wasting their money on such purely sentimental schemes.

I must now conclude, and must give place to the other geographers who have
kindly undertaken to read papers to us on many interesting subjects. All I have
attempted to do is briefly to sketch out some of the main geographical problems
connected with the opening of Central Africa in the immediate future. Such a
review is necessarily imperfect, but its very imperfections illustrate the need of
more accurate geographical information as to many of the districts in question.
Many blunders may have been made by me in consequence of our inaccurate know-
ledge, and, from the same cause, many blunders will certainly be made in future by
those who have to lay out these routes into the interior. In fact my desire has
been to prove that, notwithstanding the vast strides that geography has made in
past years in Africa, there is yet an immense amount of valuable work ready for
anyone who will undertake it.

Possibly, in considering this subject, I have been tempted to deviate from the
strictly geographical aspect of the case. Where geography begins and where it
ends is a question which has been the subject of much dispute. Whether geography
should be classed as a separate science or not has been much debated. No doubt
it is right to classify scientific work as far as possible; but it is a fatal mistake to
attach too much importance to any such classification. Geography is now going
through a somewhat critical period in its development, in consequence of the
solution of nearly all the great geographical problems that used to stir the imagina-
tion of nations ; and for this reason such discussions are now specially to the fore.
My own humble advice to geographers would be to spend less time in considering
what geography is and what it is not; to attack every useful and interesting
problem that presents itself for solution; to take every help we can get from every
quarter in arriving at our conclusions ; and to let the name that our work goes by
take care of itself.

Brifish Association for fhe Advancement
of Science.

LIVERPOOL, 1896.

ADDRESS

TO THE

ECONOMIC SCIENCE AND STATISTICS SECTION

BY

The Right Hon. LEONARD COURTNEY, M.A., M.P.,
PRESIDENT OF THE SECTION.

WsaeEn the British Association revisits a town or city, it is the laudable custom
of the President of a Section to refer to what was said by his predecessor in the
same chair on the former occasion. I should in any case be disposed to follow this
practice, but I could not choose to do otherwise when I find it was my honoured
friend Professor Jeyons who cccupied this place in Liverpool in 1870. He was
one of a group which passed away in quick successicn, to the great loss of the study
of Economics in this country, since each had much premise of furtber usefulness, and
left us with labours unfulfilled. Bagehot, Cairnes, Cliffe Leslie, Fawcett, Jevons,
occupied a large space in the field of economic study, and no one among them
excelled Professor Jevons in the vigour and clearness of his analysis or in the sin-
cerity and range of his speculations, His first work which arrested public attention
was perhaps not so much understood as misunderstood. This busy, bustling, hurrying
eae cannot afford time to pause and examine the consecutive stages of a drawn-
out argument, and too many caught up and repeated to one another the notion that
Jevons predicted a speedy exhaustion of our coalfields, and they and their successors
have since been congratulating themselves on their cleverness in disbelieving the
prophecy. No such prophecy was in truth ever uttered. The grave warning that
was given was of the impossibility of continuing the rate of development of coal
production to which we had been accustomed, of slackening, and even arrested
growth, and of the increasing difficulty of maintaining a prosperity based on the
relative advantages we possessed in the low cost of production of coal; and this
warning has been amply verified in the years that have since passed, as will be at
once admitted by all who are competent to read and understand the significance
of our subsequent experience. But I must not dwell on this branch of Jevons’s
work nor on the many other contributions he made to the study of our economic
life. Tam concerned with what he said here twenty-six years since.

At first sight the address of my predecessor may seem loose and discursive ; but
viewed in due perspective, it appears a serious inquiry into the apparent failure of
economic teaching to change the course and elevate the standard of our social life,
and an earnest endeavour to impress these principles more strongly on the public
mind so that the future might better the history he reviewed. He referred to the
repeal of the Corn Laws, and owned with regret that the condition of the people
was little changed, that pauperism had scarcely abated, that little forethought was
shown by the industrial classes in preparing for the chances of the future ; and he
dwelt on the mischievous influence of the unthinking benevolence of the wealthy
in undermining provicence by its constant and increasing activity in mitigating the

EF

2 REPORT—1896,

evils of improvidence. Jevons was not content to condemn the doles of past
testators ; he wanted the reorganisation of the Hospital service of our towns, so that
as far, at least, as the ordinary and inevitable casualties of sickness and accident are
concerned, they might be met by the co-operation of workers inspired by motives
of self-reliance instead of by ever open gratuitous service making forethought un-
necessary and even foolish. In this connection it may be noticed that while giving
a hearty welcome to Mr. Forster's Edueation Act, passed in the same year that he
spoke, he noted with satisfaction that primary education had not been made gra-
tuitous so as to take away another support of prudence. It is strange, too, in the
light of our recent experience, to find him regretting that the task of remodelling
local taxation had not been undertaken, so that local wants might be met by a just
apportionment of their charge and the principles of association of the members of
local communities placed on a firmer basis.

It will be seen that what really occupied the mind of my predecessor was the
apparent slow success of Economic thinkers in influencing political action, and
we, looking back over the intervening twenty-six years, have certainly no more
cause of congratulation than he felt ; we are forced to ask ourselves the same ques-
tion what is the reason of our apparent failure; we are driven to examine anew
whether our principles are faulty and incomplete or whether the difficulties in their
acceptance, they being sound, lie in the prejudices of popular feeling which politi-
cians are more ready to gratify than to correct.

I do not pause to meet the charges of inhumanity or immorality which have in
other times been brought against Economists. Jevons pleaded for the benevolence
of Malthus, who might indeed be presumed, as an English clergyman, to be not
altogether inhuman or immoral. In truth everyone who has ever had any thought
about social or fiscal legislation—and we have had such laws among ourselves for
five centuries—everyone who has ever tried to influence the currents of foreign
trade—and such attempts date from an equally remote past—has been moved by some
train of economic reasoning, and must strictly be classified as an Economist ; and
the only difference between such men and those who are more usually recognised
by the name is that the latter have attempted to carry their thoughts a little
further,and have been more busy to examine the links of their own reasoning and
the soundness of their conclusions. The men who attempted to fix wages, to limit
the numbers in special trades, to prohibit or to compel certain specific exports, all
had some notion that they were engaged in doing something to strengthen if not
to improve the better organisation of communities. Even the aims which appear
to us most selfish were disguised as embodying social necessities. But by the
beginning of the present reign it may be said that the study of Political Economy
in this country had worked itself free from earlier errors, and it had come to be
believed that the secret of social regeneration lay in the utmost allowance of free-
dom of action to every individual of the community, so far at least as that action
affected himself, coupled with the most complete development of the principle of
self-reliance, so as to bring home to every member, freed from legal restraint on
his liberty of action, the moral responsibility of self-support and of discharging the
duties, present and to come, of his special position. With this education of
the individual in self-reliance, and with this liberation of the same individual in
the conduct of life, it was held that by certain, if slow, stages the condition
of the community would be improved, and a wholesome reorganisation naturally
effected.

Whatever view we may now hold of this belief, whether we must discard it as
incomplete or even erroneous, or whether we remain strong in the conviction of its
intrinsic soundness and in the possibility of realising the hopes it offered, it must
still be evident that those who professed it were imbued with the deepest interest
in the well-being of their fellow creatures, and that the aim of all their speculations
was the purification of social life, and its healthy and abundant development.

Such was the theory more or less openly expressed by Economie thinkers when
the British Association was founded, and the same theory, as I conceive, lay at the
base of Jevons’s address in 1870. Can we hold it now, or must it be recast ?

Since 1870 Primary Education has practically been made gratuitous. The

9

TRANSACTIONS OF SECTION F. 3

Legislature had an opportunity for abolishing the mischief of doles, but showed no
inclination to make use of it, and there were even traces of a feeling of favour for
the maintenance of these bequests of the past. The indiscriminate multiplication
of so-called charitable institutions has in no way been reformed, and there is as
great activity as ever in the zeal of those who would mitigate or relieve the effects
of improvidence without touching improvidence itself. As far as the course of
legislation is concerned, it may be feared that it has been directed to diminish
rather than to increase the spirit of self-reliance. Codes of regulations have been
framed for the supervision of the conduct of special industries, and their sphere
has been extended so as to embrace at no distant period, if not now, the whole
industrial community. The reformed Poor Law, which was regarded as a great
step in the education of the workman, especially of the agricultura! labourer, in
independence, stands again upon its trial, and proposals are at least in the air for
assuring to the aged poor a minimum measure of support without any regard to
the circumstances of their past lives, or to the inevitableness of their condition.
The suggestions made by responsible statesmen have indeed been more limited and
cautious, but it will be acknowledged of those, as of the German system, from which
they may be said to be in some measure borrowed, that they involve a great depar-
ture from that ideal of individual development to which I have referred. Add to this
that there isa movement, which has become practical in many large cities and towns,
for the community itself to engross some forms of industrial activity, and to under-
take in respect of them to meet the wants of their inhabitants. All these develop-
ments and more may be summed up as illustrations of Collectivity—an ideal
which has its advocates and professors, and which looks in the future for regulated
civic and national monopolies instead of unrestricted freedom of individual
activity, and for the supervision and control of those industries which may
remain unabsorbed by state or town. In pursuit of this last conception there
have been put forward not only requirements as to hours and conditions of
labour, but a demand also for a Living Wage or a minimum, below which no
workman shall be paid; and this principle has been already adopted by some muni-
cipalities in respect of their monopolised industries. The State itself indeed has,
through the popular branch of the legislature, declared more or less clearly in
favour of the same principle in respect of the industries which are conducted in
its service.

We have not only to acknowledge the continued slowness of politicians to
adopt and enforce the teaching of Economists such as Jevons contemplated, but
also the rise of another school of Economic thought which competes for, and in
some measure successfully obtains, the attention of the makers of laws. The
question which has already been suggested thus becomes inevitable. We must
inquire whether the failure of former teaching has not been due to errors in itself
rather than to the indocility of those who have neglected it.

The greatest difficulty which the teachers of the past have to overcome when
put upon their self-defence lies in the suspicion, or more than suspicion, of an
occupied multitude that their promises have failed. It is thought of them, if it
is not openly said, that they had the ear of legislators for a generation, that the
course and conduct of successive administrations were governed by their principles,
and yet society, as we know it, presents much the same features, and the lifting up
of the poor out of the mire is as much as ever a promise of the future. Some
quicker method of introducing a new order is called for, and any scheme offering
an assurance of it is welcomed. A ready answer can be given to much of the
suspicion of failure that is entertained. That freedom of industrial action, which
is the first postulate of the Economists, has never been secured. We are so much
accustomed to the conditions of our own life that this declaration may seem
strange to many, who will say that at least in England labour and trade are free ;
but it must be admitted, on reflection, that in one great sphere of action the liberty
so sea ag has, for good or bad reasons, never been conceded. The limitations
and restrictions necessarily consequent upon the system of land laws established
among us are not commonly understood, but although much has been done to libe-
rate agriculture from their fetters, its perfect freedom has not been attained. There

4, REPORT—1896.

may be free trade in the United Kingdom and free land in the United States,
but the country is yet to be found in which both are realised, and even if
both these requisites were attained the sores of social life would not be
removed unless the spirit of self-reliance were fully developed: and how little has
been done to secure this essential condition of progress! nay, how much has
been done by law, and still more by usage, to weaken and destroy its power!
The Economist of whom I have been speaking may boldly claim that so far as he
bas had a free hand, his promises have been realised; there has been a larger
population with increased means of subsistence and diminished necessity of Pees
people better housed, better fed, better clothed, with fewer relative failures of self-
support ; and if the teaching which has been partially adopted has brought about
so much, everything it promised would have been secured had it been fully
followed. If the teaching had been fully followed? This raises the question
whether there are inherent difficulties in the nature of man preventing such a con-
summation, and many will be ready with the answer that such difficulties exist,
are permanent and cannot be surmounted. As long as human nature is what it is
—so runs the current phrase—men will not see misery without relieving it, they will
not wait to inquire into its cause and whether it could have been prevented, and it
is claimed that this instinct is one of the best attributes of humanity, which we
should not attempt to eradicate. This kind of reply easily catches the popular ear.
It seems generous, sympathetic, humane. But it is based on a view of human
nature being incapable of education which has been and will long be the excuse for
acquiescence in all imperfections and even iniquity;.nor can that be said to be
truly generous, sympathetic, or humane which refuses to inquire into the possi-
bility of curing disease, and prefers the selfishness of self-relief to the patient
endeavour to probe and remove the causes of the sufferings of others. The
Economist of the past generation would, I think, be justified in repudiating with
warmth the feeble temper which recoils from the strenuousness of endeayouring to
deal with social evils at their origin, and in reprobating the acceptance as inevi-
table of vices we take no pains to prevent. This, however, does not conclude the
whole matter. Even if we did attain the ideal of bringing home to all the members
of the community the fatal consequences of improvidence and vice, should we find
improvidence and vice ever narrowing into smaller and smaller circles, or should we
be confronted with their existence as before, with this difference, that past attempts
toalleviate their miserable consequences would be discredited and abandoned? I fear
I must here confess to a somewhat faltering faith. That a vigorous enforcement
of the penalties of improvidence would diminish it, is a conclusion justified by
experience as well as suggested by theory ; but that it and its consequences would not
still remain gross and palpable facts is a conclusion I have not the courage to gain-
say. At all events, I cannot refuse to consider the question whether something
more than the complete freedom of the individual is not necessary for the reforma-
tion of society, and to examine with an open mind any supplementary or alternative
proposals that may be made to reach this end. Yet one thing must be said, and
said with emphasis, of the theory of the Economist. It was a working theory. No
theory can be accepted even for examination which does not show a working
organisation of society, and the theory we have had under review has this necessary
characteristic, even if it does not open up a certain way to a perfect reconstruction
of our social system.

It will be conceded by the most fearless and thorough-going advocates of the
liberty of individual development, that it must be supported by large measures of
co-operative action. No individual can by any amount of forethought protect himself
by himself against the chances and accidents of the future. No one can tell beforehand
what is in store for himself in respect of sickness, or accident, or those changes of cir-
cumstances which may arise from the default of others; and mutual aid is necessary
to meet such contingencies. ‘The freedom and activity of association thus indicated
are in no way inconsistent with the fullest theory of individual responsibility. Nor
is there any departure from it in the voluntary combination among themselves of
persons, individually weak, to supervise and safeguard the economic conditions into
which they may enter with others relatively stronger. A single workman may be

TRANSACTIONS OF SECTION F. 5

powerless to induce his employer to modify in any particular the terms of his
employment, but when workmen band together they may meet employers as equal

owers. Such liberty of combination is a development and not a limitation of
individual liberty. Another step is taken when the parties to such an arrange-
ment as has been suggested seek to make its provisions compulsory on others, be
they workmen or employers, who may enter into similar relations; and the prin-
ciples of former Economists would generally prompt them to condemn such
attempts at compulsion. The Factory Acts were opposed in this way, although
they rested upon different grounds; for, though in their consequences they affected
the labour of adults, they were propounded for the defence of young persons and
children unable to protect themselves or to be the parties to free contracts. Legis-
lation has, however, been extended to control directly the employment of fully
responsible persons, and this has been defended by three lines of argument. It is
urged that when the unchecked liberty of individuals destroys in fact the liberty
of action of larger multitudes, it is in defence of liberty of action that those
individuals are controlled. If a sea wall is necessary to prevent h large tract from
being periodically inundated, it cannot be permitted to the owner of a small patch
along the coast to leave the wall unbuilt along his border, and thus threaten the
lands of his neighbours with inundation. Again, it is urged that when the over-
whelming majority of persons engaged in a particular industry, employers and
employed, are agreed upon the necessity of certain rules to govern the industry, it
is not merely a convenience, but is a fulfilment of their liberty, to clothe with the
sanction of law the regulations upon which they are agreed. Lastly, it is sub-
mitted that there are individuals in whom the sense of responsibility is so weak
and whose development of forethought is so hopeless, that it is necessary the law
should regulate their conduct as it may regulate the conduct of children. I do
not propose to examine in detail these real or apparent limitations of individual
liberty. The first plea appears to me to be sound in principle, though it may often
have been applied to cases not properly coming within it. As to the second, the
convenience of giving to an all but universal custom the force of law is incontestable,
but it is at least doubtful whether this is sufficient to deprive individuals who
deliberately wish to put themselves outside it of the liberty of doing so. Unless
their action could be brought within the first line of argument, sufficient reason for
restraint does not appear. As for the hopeless class whose existence is made a
plea for restrictive legislation, the Economist may forcibly argue that they have
never been left to learn the full force of the lessons of experience, and it is the
impatient interference of thoughtless men and thoughtless laws which allows this
class to be perpetually recruited.

The limitations of individual liberty, to which I have referred, are familiar to
us, and have obtained a firm hold in our legislation; but we enter upon compara-
tively new ground when we turn to the proposals that an increasing number of
industries should be undertaken and directed by State or Municipality, and that a
minimum and not inadequate subsistence should be assured to all those engaged in
such industries, if indeed the principle be not presently extended outside the
monopolies so established. The ideas which are clothed in the phrases ‘The
socialisation of the instruments of industry,’ and ‘The guarantee of a minimum
wage to all workmen,’ appear to involve a complete reorganisation of society, and
an absolute abandonment of the theories of the past. This is not enough to justify
their immediate rejection or their immediate acceptance. The past has not been
so good that we can refuse to look at any proposals, however strange in appearance,
offering a better promise for the future. It has not been so bad that we must
abandon its methods in despair, as if no change could be for the worse, if not for
the better. A patient inquirer, feeling his way along the movement of his time,
may even be constrained to accept a patchwork covering of life instead of the ideal
garment woven without seam throughout; or he may be led to see that the
harmony of society, like the harmony of the physical universe, must be the result
of divers forces, out of which is developed a perfect curve.

No one could now be found to deny the possibility, and few to question the
utility, of the socialisation of some services. The post office is in all civilised

6 REPORT—1896.

countries organised as a national institution, and the complaints that are some-
times heard as to defects in its administration never extend to a demand for its
abolition. Jevons, in a careful paper, showed that the same financial success
which marks our present postal system, must not be expected from the nationalisa-
tion of the telegraph service, and be dismissed even suggestions for the nationalisa-
tion of railways. His predictions have been amply verified with respect to the
telegraph account; but telegraphs are a national service amongst ourselves, and
railways are largely nationalised in many continental countries, and in some of our
own colonies and dependencies. Some of our largest municipalities have under-
taken the supply of water and of gas, or even of electric light, to the inhabitants,
and a movement has begun, which seems likely to be extended, of undertaking the
service of tramways. Demands have also been made for the municipalisation or
nationalisation of the telephone service.

It may be said of all the industries thus described as taken oyer, or likely to be
taken over, by the nation and local communities, that when they are not so taken
over they require for their exercise special powers and privileges conceded by the
State or community, and the conditions of such concessions are settled by agree-
ment between the community and the body or bodies exercising such industries.
These conditions may involve the payment of a fixed sum, or of a rent for the
concession, or the terms upon which the services are to be rendered may be
prescribed in a stipulated tariff of charges, or the amount of profit to be realised
by the concessionaires may be limited with provisions for reduction of charge
when such limit is reached, or it may be required that in working such industries
certain limits of wages shall be observed as the minima to be paid to the work-
men employed upon them. Speaking very broadly, it may be said that the
community delegates or leases the right of practising the industry, and there is no
impassable gulf between prescribing the terms on which a lease shall be worked
and assuming the conduct of the industry leased. There may be difficulties in
tle management by a community of a cumbrous and unwieldy undertaking, but
there is no difficulty affecting the organisation of society when the undertaking
must be created and shaped by the community in the first place. The arguments
against the assumption of such monopolies by State or Local Authorities are those
of expediency, founded on a comparison of gain and loss. It may be urged that
there are more forcible motives of economy on the part of a concessionaire than on
the part of a community working the undertaking itself; that improvements of
method and reductions of cost will be more carefully sought; and although such
improvements and reductions might in theory be realised by the workmen and
agents of a community, which would thus secure all the savings effected by them,
yet private interest is quicker in discovery and more fertile in suggestion, and
it is more profitable in the end for the community to allow a concessionaire to
secure such profits, subject to a stipulation that some part of them should return to
the community in the way either of increased money payment, or of reduced rates
of charge fur the services performed. It may be urged that when a community
works an industry itself, it may do so at a loss, thus benefiting those who specially
require its services at the cost of the whole body; but this objection is not peculiar
to undertakings so directly worked. It is a matter of common experience for State
or Municipality to grant important subventions to persons willing to undertake
such works on stipulated terms of service, and such subyentions involve a levy
from the whole community for the benefit of those availing themselves of the
services,

New considerations of great difficulty arise when we pass to the suggestion of
the undertaking by local authorities of productive industries not in the nature of
monopolies. In monopolies direct competition, often competition in any shape,
is practically impossible; in other industries competition is a general rule; and it is
by virtue of such competition that the members of the community do in the long
run obtain their wants supplied in the most economical manner. When com-
modities are easily carried without serious deterioration, the constantly changing
conditions of production and of transport induce a constant variation in the sources
of cheapest supply—that is of supply under conditions of least toil and effort-—

TRANSACTIONS OF SECTION F,. 7

and any arrest of this mobility involves a corresponding set-back in the advance-
ment of the economic condition of mankind. It is a necessary consequence
’ of this process that the local production of special commodities should be subject
to diminution and extinction, and that the labours hitherto engaged in such local
production should become gradually worthless. Quite as much labour as before
might be expended in achieving the result, but it would be misapplied ; it
ought not to command the same return; it should cease, It is at least difficult to
foresee how far the production of commodities exposed to free competition could
be maintained by communities themselves in face of the movement we have
described. There would be a danger of pressure to do away with invasive com-
petition—action which, in my judgment, would be destructive of the most powerful
cause of improvement in the condition of the people. There would be an allied
danger of a refusal to recognise the possibility of a diminished worth of work
which remains as toilsome as ever, and of an increasing congestion of labour when
the great movement of the world demands its dispersion It may be that those
evils are not inevitable, but they would require to be faced if any serious attempt
were made to increase the range of national or municipal industries, and I haye not
yet seen any attempt at their serious investigation.

The position thus taken may be illustrated by an experience to which I have
elsewhere referred, but so pregnant with suggestion that I need not apologise for
recalling it. My native county, Cornwall, was in my boyhood the scene of wide-
spread activity in copper and tin mining. There had not been wanting warnings
that the competition of richer deposits in far countries would put an end to these
industries in the county, but the warnings had not been realised and remained
unheeded. In the years that have since passed they have been gradually and
almost completely fulfilled. There are no copper mines now in Cornwall, and the
tin mines, which were scattered far and wide throughout the county, are reduced
to two or three within one limited area. It is not the case that the ores have
been exhausted; they could still be raised, but at a cost of production making the
process unprofitable. The mines were abandoned one by one, and the population
of the county has steadily diminished in every recent census. What would the
experience have been had the mines been a county or national property worked by
county or nation? I do not stop to comment on the difficulty of expropriating
present owners, which, however, must not be forgotten. If the collective owner
had leased the mines to companies of adventurers (to use the local phrase), the
lessees would have gradually relinquished their concessions, as they have done
when taking them from private owners. Nor would the case have been materially
different even if the collective owner had introduced the novel stipulation into his
leases that the working miners should be paid according to prescribed rates of
wages. The process of relinquishment might have been precipitated and accelerated
by insisting on such a condition, but otherwise the experience would have been the
same. The shrinkage of industry would go on without a check, and it is to be
hoped that the workmen who found their work failing would, with the fine courage
ana enterprise they have in fact shown, have betaken themselves to the fields of
mining industry displacing their own in all parts of the world. Can one think that
the same process would have been maintained had the collective owner worked
the mines directly, and the working men looked to county or nation for the con-
tinuance of work and wages? The attachment which all men have for the homes
of themselves and their fathers would have stimulated a demand for a recurrence
to the other resources of the collective owner for the maintenance of an industry
that was dying. Some demand might even be made for a repression or prohibition
of that competition which was the undoing of the local industry. These possi-
bilities may be regarded as fanciful, and it is true that forces might be kept under
control that operated within an area and affected a population relatively so
limited. But what if the warnings of Jevons respecting coal in England proved like
the warnings of the men who foresaw the cessation of tin mining in Cornwall, and
the community had to deal with the problem of the dwindling coal industry in
face of nationalised coal mines and armies of workmen employed by the nation ?
The initial difficulties of the nationalisation of that which for centuries has been

8 REPORT—1896.

the subject of private property are formidable, but they could doubtless be overcome
by the short and simple process of confiscation. This transformation is theoretically
conceivable. It is in the subsequent development of the scheme of nationalised and
municipalised industries that we are confronted with tasks not so easy of solution.
How is its working to be reconciled with that opening up of more and more pro-
ductive fields which is one of the prime factors of social progress? How is the
allotment of men to be directed so that they may be shifted about as new centres
open and old centres close? What checks or commands can be invoked to restrain
the growth of population in a district when it should be dwindling? These are
questions that can scarcely be put aside, and it may even be acknowledged that
they gain fresh force when viewed in the light of another experience, Agricul-
tural industry has recently been subjected to severe trials through a great breadth
of this country. This has been due to cheaper importations from other lands, and
though the competition has in my judgment been aggravated by causes into which
I will not now digress (which aggravation however might and should be dealt
with), the importation of food at less cost is a result no Economist will regard
as otherwise than beneficial to the community as a whole. It is well that
bread and flesh and the sustenance of life should be procured with as little toil as
possible, however severe the trial for those who have been engaged hitherto in
the production of those necessaries. We know that it has been so severe that
demands for relief and assistance have been loudly made, and their power has been
such as to have been in some measure successful; but had land been nationalised
and farms held from the State or from county, town, or parish, they would have
assumed a different shape, have been urged with greater purpose, and have received
larger treatment. The difficulties ofssuch a nationalised industry, passing into what
may be described as a water-logged condition, would test beyond the straining point
such statesmanship as our experience warrants us to believe possible.

However much we may contemplate the reconstruction of an industrial system,
it must, if it is to be a living social organism, be constantly responsive to the ever-
changing conditions of growth ; some parts must wax whilst others wane, extend-
ing here and contracting there, and manifesting at every moment those phenomena
of vigour and decline which characterise life. Inthe development of industry new
and easier ways are constantly being invented of doing old things; places are
being discovered better suited for old industries than those to which resort had
been made ; there is a continuous supersession of the worth of known processes and
of the utility of old forms of work involving a supersession, or at least a transfer, of
the labour hitherto devoted to them. All these things compel a perpetual shifting
of seats of industry and of the settlements of man, and no organisation can be enter-
tained as practicable which does not lend itself to those necessities. They are the
pre-requisites of a diminution of the toil of humanity. As I have said before, the
theory of individual liberty, however guarded, afforded a working plan ; society
could and did march under it. The scheme of collective action gives no such
lea of practicability ; it seems to lack the provision of the forces which should

ring about that movement upon which growth depends. The Economist of the
past generation still holds his ground, and our best hips lies in the fuller accept-
ance of his ideas. Such, at least, appears to me to be the result of a dispassionate
inquiry ; but what may be wanting is something more than a dispassionate temper—
a certain feryour of faith. The Economist must feel, if he is to animate multitudes
and inspire legislatures, that he, too, has a religion. Beneath the calmness of his
analysis must be felt the throb of humanity. Slow in any case must be the secular
progress of any branch of the human family; but if we take our stand upon facts,
if our eyes are open to distinguish illusions from truth, if we are animated by the
single purpose of subordinating our investigations and our actions to the lifting up
of the standard of living, we may possess our souls in patience, waiting upon the
promise of the future.

Spottisrcoode | 5 Co. Printers, New-street Square, London.

=

Brifish Association for fhe Advancement of
Science.

LIVERPOOL, 1896.

ADDRESS

TO THE

MECHANICAL SCIENCE SECTION

BY

Sirk DOUGLAS FOX, Vice-President Institution of Civil Engineers,
PRESIDENT OF THE SECTION.

Ir is rather over a quarter of a century since the British Association last held
its meeting in the hospitable city of Liverpool. The intervening period has been
one of unparalleled progress, both generally and locally, in the many branches of
knowledge and of practical application covered by Civil and Mechanical Engi-
neering, and therefore rightly coming within the limits for discussion in the
important Section of the Association in which we are specially interested,

During these twenty-five years the railway system of the British Isles, which
saw one of its earliest developments in this neighbourhood, has extended from
15,576 miles, at a capital cost of 552,680,000/., to 21,174 miles, at a capital cost of
1,001,000,0007. The railway system of the United States has more than trebled
in the same period, and now represents a total mileage of 181,082, with a capital
cost of $11,565,000,000,

The Forth and Brooklyn, amongst bridges, the Severn and St. Gothard,
amongst tunnels, the gigantic works for the water-supply of towns, are some of
the larger triumphs of the civil engineer ; the substitution of steel for iron for so
many purposes, the perfecting of the locomotive, of the marine engine, of hydraulic
machinery, of gas and electric plant, those of the mechanical branch of the pro-
fession.

The city of Liverpool and its sister town of Birkenhead have witnessed
wonderful changes during the period under review. Great and successful efforts
‘have been made to improve the watergate to the noble estuary, which forms the
key to the city’s greatness and prosperity ; constant additions have been made to
the docks, which are by far the fnest and most extensive in the world. The
docks on the two sides of the river have been amalgamated into one great trust.
In order properly to serve the vast and growing passenger and goods traffic of the
port, the jaa railway companies haye expended vast sums on the connections
with the dock lines and on the provision of station accommodation, and there have
been introduced, in order to facilitate intercommunication, the Mersey Railway,
crossing under the river, and carrying annually nearly 10 millions of passengers,
and the Liverpool Overhead Railway, traversing for six miles the whole line of
docks, and already showing a traffic of 7 millions of passengers per annum. A
very complete waterside station connected with the landing-stage has been lately
opened by the Dock Board in connection with the London and North-Western
Railway. In addition to this, the water-supply from Rivington and Vyrnwy has
now been made one of the finest in the world.

G

2 REPORT—1896,

The following comparative figures, kindly supplied by Mr. K. Miles Burton, —
may be of interest :—

1871 1895
Population of Liverpool . - A - 493,405 : : 641,000 (Estimated)
‘s Birkenhead 5 so te MOS ae P - 109,000 W
Area of docks, Liverpool, about ~ . : 236 acres. 3624 acres
ie ce Birkenhead, about . 5 aT Ps 3 LEGO aes
383 5225
Number of steamers using the port - 7,448 b : 18,429
Average tonnage of six largest vessels
entering the port . 5 : 2 2,890 A 4 6,822

The following figures show the importance of the local railway traffic :—

Number of passenger stations within the

boroughs. : - . - c — : : 58
Number of goods stations : ‘ = — ‘ f 50
Number of passengers crossing the Mer- .

sey in the twelve months (Woodside

Ferry). 5 3 : ‘ : é — : « 7,143,088
Number of passengers crossing the Mer-

sey in the twelve months (Mersey ,

Railway) . o 5 . 5 5 — . . 6,976,299

To the hydraulic engineer there are few rivers of more interest, and present-
ing more complicated problems, than the Mersey and its neighbours, the
Dee and the Ribble. They all possess vast areas of sand covered at high water,
but laid dry as the tide falls, and in each case the maintenance of equilibrium
between the silting and scouring forces is of the greatest importance to the welfare
of the trading communities upon their banks. The enclosure of portions of the
areas of the respective estuaries for the purposes of the reclamation of land, or for _
railway or canal embankments, may thus have far-reaching effects, diminishing the
volume of the tidal flow and reducing the height of tide in the upper reaches of
the rivers. Some idea of the magnitude of these considerations may be derived
from the fact that a spring tide in the Mersey brings in through the narrows
between Birkenhead and Liverpool 710 millions of cubic yards of water to form a
scouring force upon the ebb. The tidal water is heavily laden with silt, which is
deposited in the docks, and, at slack water, upon the sandbanks. The former is
removed by dredging, and amounts to some 1,100,000 cubie yards per annum ;
the latter is gradually fretted down into the channels and carried out to sea before -
the ebb. Whilst a considerable portion of the narrows is kept scoured, in some
places right down to the sandstone rock, there is a tendency, on the Liverpool side,
near the landing-stage, to silt up, a difficulty counteracted, to some extent, by the
extensive sluicing arrangements introduced by Mr. George Fosbery Lyster, the
engineer of the Mersey Docks and Harbour Board.

Very extensive and interesting operations have been carried on by the Board
in connection with the bar at the mouth of the river. Dredgers specially designed
for the purpose have been employed for some six years, with the result that
15,142,600 tons of sand and other dredged matter have been removed, and the
available depth of water at low-water increased from 11 to 24 feet in a channel
1,600 feet in width.

Those who have made the transatlantic passage in former years can more
readily appreciate the very great advantage accruing from this great improvement.

Formerly vessels arriving off the port on a low tide had to wait for some hours
for the water-level to rise sufficiently to enable them to cross the bar; the result of a
large vessel lying outside, rolling in the trough of the sea with her engines stopped,
was that not infrequently this proved to be the worst part of the voyage between
New York and Liverpool, and passengers who had escaped the malady of sea-

TRANSACTIONS OF SECTION G. 3

sickness throughout the voyage were driven to their cabins and berths within three
or four hours of landing.

Owing to the very successful dredging operations, ships of largest size can now
enter or depart from the Mersey at any state of the tide, and they are also able to
run Elongeiae the landing-stage without the intervention of a tender.

Such vessels as the ‘Teutonic’ or ‘ Majestic,’ of nearly 10,000 registered tonnage,
566 feet in length, 57 feet wide, and 37 feet deep; or the still larger vessels, the
‘Campania’ or ‘ Lucania,’ of nearly 13,000 tons register, 601 feet in length, 65 feet
in width, and 38 feet in depth, can be seen, on mail days, lying alongside.

Whilst the estuary of the Mersey presents a narrow entrance with a wide
internal estuary, the Dee, owing to extensive reclamation of land in the upper
reaches, has a wide external estuary leading to an embanked river of very limited
width, up which the tide rushes with great velocity laden with silt, rising in some
two hours, then, during a short time of slack water, depositing the silt, which is
not removed by the ebb-tide, spread over some ten hours, and therefore having
comparatively little velocity. In this case, also, the outer estuary shows a great
tendency to silt up beyond the reach of any but the highest spring tides.

The reclamation of the Ribble has not yet proceeded so far as to so seriously
affect the general conditions of the estuary; but here, also, there is a constant
tendency in the channels to shift, and the erosion which takes place when a high
tide and wind combine is very remarkable.

A most important improvement was introduced in 1886, by Mr. G. F, Lyster,
when it was decided to raise the water-level in certain of the docks by pumping,
the wharves being heightened in proportion, and half-tide basins, or locks, made
use of to compensate for the difference of level.

The area of the docks so treated in Liverpool is 78 acres, whilst at Birkenhead
the ee area of the docks on that side of the river, amounting to 160 acres, is so
raised.

The hydraulic power used in the docks is very large, the indicated horse-power
of the engines amounting to 1,673 in the case of Liverpool, and 874 in that of
Birkenhead ; whilst the Hydraulic Power Company are supplying some 1,000 h.p.
to railways and private firms.

The direct-acting hydraulic lifts of the Mersey Railway have now been at work
for ten years, and through these, at St. James’s Station, no less than 75,000,000 to
80,000,000 of passengers have passed with regularity and safety.

It is remarkable that, whilst Great Britain led the van in the introduction of
steam locomotion, she has lagged in the rear as regards electric and other
mechanical traction. This arose in the first instance from mistaken legislation,
which strangled electrical enterprise, which is still much hampered by the reluctance
of public authorities to permit the introduction of the necessary poles and wires
into towns.

At the date of the latest published returns there were at work in the United
States no less than 12,133 miles of electric, in addition to 599 miles of cable,
tramway. Hardly a large village but has its installation, and vast have been the
advantages derived from these facilities. In Brooklyn one company alone owns
and works 260 miles of overhead trolley lines. With the exception of some small
tramways at Portrush, Brighton, Blackpool, South Staffordshire, Hartlepool, &c.,
the only examples in this country of serious attempts to apply electro-motive force
to the carriage of passengers are the City and South London Railway and the
Pore. Overhead Railway, the latter being the latest constructed, and having,
therefore, benefited by the experience gained upon the London line.

This railway is over six miles long, a double line of the normal, or 4 ft. 84 in.
gauge, running on an iron viaduct for the whole length of the docks; the installa-
tion is placed for convenience of coal supply about one-third of the distance from
the northern end. Particulars of this interesting work will be placed before the
Section, but suffice it to say that a train service of three minutes each way is
readily maintained, with trains carrying 112 passengers each, at an average speed
of twelve miles per hour, including stoppages at fourteen intermediate stations.

4 REPORT—1896.

During the last year, as before stated, 74 million passengers were carried, the cost —
of traction per train mile being 34d.

The Hartlepool Tramway is proving successful, overhead trollies and electric
traction having taken the place of a horse tramroad, which was a failure from a
traffic point of view.

Careful researches are being prosecuted, and experiments made, with the —
intention of reducing the excessive weight of storage batteries. If this can be
effected, they should prove very efficient auxiliaries, especially where, in passing
through towns, underground conductors are dangerous, and overhead wires
objectionable. :

In connection with electric traction, it is very important to reduce, if possible,
the initial force required for starting from rest. Whether this will be best attained
by the improvement of bearings and their better lubrication, or by the storage, for
starting purposes, of a portion at least of the force absorbed by the brakes, remains
to be seen, but it is a fruitful field for research and experiment.

In the United States there is a very general and rapid displacement of the
cable tramways by the overhead wire electric system. The latter has many oppo-
nents, owing, probably, to causes which are preventible.

Many accidents were caused by the adoption-of very high tension currents,
which, on the breakage of a wire, were uncontrollable, producing lamentable
results,

The overhead wires were placed in the middle of the street, causing interference
with the passage of fire-escapes. :

‘The speed of the cars was excessive, resulting in many persons being run over.

The cable system, therefore, found many advocates, but the result of experience
is in favour of electrical traction under proper safeguards.

The cable system can only compete with the electric system when a three-
minute or quicker service is possible, or, say, when the receipts average 20/. per
mile per day; it is impossible to make up lost time in running, and the cars cannot
be ‘backed.’ If anything goes wrong with the cable the whole of the traffic is
disorganised. The cost of installation is much greater than in the case of elec-
tricity, and extensions are difficult. :

On the other hand, electricity lends itself to the demands of a growing district,
and extensions are easily effected; it satisfies more easily the growing demands
on the part of the public for luxury in service and car appointment. It is less
expensive in installation, and works with greater economy. By placing the wire
at the side of the street, and using a current of low voltage, the objections are
greatly minimised, and the cars are much more easily controlled and manipulated.
In cases of breakdown these are limited to the half-mile section, and do not
completely disorganise the service. Electric cars have been worked successfully on
gradients of 1 in 7. S

The conduit slot system can be adopted with good results, provided care is
taken in the design of the conduit, atl allowance made for ample depth and
clearance ; a width of 3-inch is now proved to be sufficient. Where, however,
there are frequent turnouts, junctions, and intersecting lines, the difficulties are
great, and the cost excessive.

The following figures represent the cost of a tramway, on this system, in
America :— :

£
Cost of track and conduit . . . 5,600 (per mile of single track)
Insulator, boxer, and double conductor. 480
Asphalte paving on 6 inches of concrete
to 2 feet outside double track . . 1,600
£7,580

Complete cost of operating 4 miles of double track for 24 hours
per day with 24 minute service, 4:55d, per train mile (exclusive
of interest, taxes, &c.).

One train consists of one motor car and one trailer.

TRANSACTIONS OF SEOTION G. 5

The trains make a round trip of eight miles in one hour, with three minutes
lay-off at each end.

The cost of keeping the slot clean comes to about 40/. per quarter, and the
repairs to each plough conductor about 50s. per quarter.

Attempts have been made to obviate the necessity of the slot by what is
known as the closed conduit : but at present the results are not encouraging.

The following figures will help to convey to the mind the great development
which is taking place in America, as regards the earnings upon lines electrically
equipped. They are derived from the Report of the State Board of Railroad Com-
missioners for Massacnusetts.

1888 1894 Increase
Net earnings per passenger carried eee) ‘78 62°5 per cent.
Net earning per car mile : ; . 2:78 483 73°56 ,,
Net earning per mile of road . : . £484 £762 57 y

In addition to the application of electricity for illuminating purposes, and for
the driving of tram cars and railways, it has also been applied successfully to the
driving of machinery, cranes, lifts, tools, pumps, &ce., in large factories and works.
This has proved of the greatest convenience, abolishing as it does the shafting of
factories, and applying to each machine the necessary power by its own separate
motor; the economy resulting from this can hardly be over-estimated.

It is also successfully employed in the refining of copper, and in the manu-
facture of phosphorus, aluminium, and other metals, which, before its application,
were beyond the reach of commercial application.

The extent of its development for chemical purposes in the future no one can
foresee.

It is hardly necessary to call attention to the successful manner in which the
Falls of Niagara, and the large Falls of Switzerland, and elsewhere, are being
harnessed and controlled for the use of man, and in which horse-power by thousands
is being obtained.

At Niagara, single units of electrical plant are installed equal to about 5,000
horse-power output. These units are destined to be utilised for any of the purposes
penal suggested, and it is computed that one horse-power can be obtained

m the river, and sold for the entire year day and night continuously, for the
sum of 3/. 2s. 6d. per annum.

Electric head lights are being adopted for locomotives in the United States.

The use of compressed air and compressed gas for tractive purposes is at
present in an experimental stage in this country. The latter is claimed to be the
cheapest for tramway purposes, the figures given being—

d,
Single horse cars 3 é “ - : . ; : 53
Electrical cars, with overhead wires . . 7 ; é 4}
Gas cars . : : ; : 34

Combination steam and electric locomotives, gazoline, compressed air, and hot-
water motors are all being tried in the United States, but definitive results are not
yet published.

The first electric locomotive practically applied to hauling heavy trains was
put into service on the Baltimore and Ohio Railway in 1895 to conduct the traffic
through the Belt Line Tunnel.

It is stated that, not only was the guaranteed speed of 30 miles per hour
attained, but, with the locomotive running light, it reached double that speed.

On the gradient of 8 per cent. a composite train of forty-four cars, loaded with
coal and lumber, and three ordinary locomotives—weighing altogether over 1,800
tons—was started easily and gradually to a speed of 12 miles an hour without
slipping a wheel. The voltage was 625. The current recorded was, at starting,
about 2,200 ampéres, and, when the train was up to speed, it settled down to
about 1,800 ampéres. The drawbar pull was about 63,000 lbs.

The actual working expense of this locomotive is stated to be about the same
as for an ordinary goods locomotive—viz. 23 cents per engine mile.

G2

6 REPORT— 1896.

The rapid extension of tunnel construction for railway purposes, both in towns —
and elsewhere, is one of the remarkable features of the period under review, and
has been greatly assisted by the use of shields, with and without compressed air.
This brings into considerable importance the question of mechanical ventilation.
Amongst English tunnels, ventilation by fan has been applied to those under the
Severn and the Mersey. The machinery for the latter is, probably, the most
complete and most scientific application up to the present time.

There are five ventilating fans, two of a? are 40 feet in diameter, and
12 feet wide on the blades; two of 30 feet, and 10 feet wide; and one Baa
running fan of 16 feet in diumeter, all of which were ably installed by Messrs.
Walker Brothers of Wigan. They are arranged, when in full work, to throw
800,000 cubic feet of air per minute, and to empty the tunnel between Woodside
and St. James’s Street in eight minutes ; but, unfortunately, it is found necessary,
for financial reasons, not to work the machinery to its full caper:

The intended extension of electrical underground railways will render it neces-
sary for those still employing steam traction either to ventilate by machinery or to
substitute electro-motive force. J

Great improvements have been lately made in the details of mechanical venti-
lators, especially by the introduction of anti-vibration shutters, and the driving
by belts or ropes instead of direct from the engine. The duties now usually
required for mining purposes are about 300,000 cubic feet of air per minute with
a water-gauge of about 4 inches; but one installation is in hand for 500,000 cubic
feet of air per minute, with a water-gauge of 6 inches.. Water-gauge up to 10
inches can now be obtained with fans of 15 feet diameter only.

An interesting installation has been made at the Pracchia Tunnel on the
Florence and Bologna Railway. J

The length of the tunnel is 1,900 metres, or about 2,060 yards; it is for a
single line, and is on a gradient of 1 in 40. When the wind was blowing in at the
lower end, the steam and smoke of an ascending train travelled concurrently with
the train, thus producing a state of affairs almost unimaginable except to those
engaged in aaa the traffic.

Owing to the height of the Apennines above the tunnel, ventilating shafts are
impracticable ; but it occurred to Signor Saccardo that, by blowing air b means
of a fan into the mouth of the tunnel, through the annular space which exists
between the inside of the tunnel arch and the outside of the traffic gauge, @
sufficient current might be produced to greatly ameliorate tbe state of things.

The results have been most satisfactory, the tunnel, which was formerly
almost dangerous, under certain conditions of weather, being now kept cool and
fresh, with but a small expenditure of power.

In an age when, fortunately, more attention is paid than formerly to the well-
being of the men, the precautions necessary to be observed in driving long-
tunnels, and especially in the use of compressed air, are receiving the consideration
of engineers. In the case of the intended Simplon Tunnel, which will pierce the
Alps at a point requiring a length of no less than 124 miles, a foreign commission
of engineers was entrusted by the Federal Government of Switzerland with an
investigation of this amongst other questions. 3

During the construction of the St. Gothard Tunnel, which is about 10 miles
in length, the difficulties eneountered were, of necessity, very great; the question
of ventilation was not fully understood, nor was sanitary science sufficiently ad-
vanced to induce those engaged in the work to give it much attention. The
results were lamentable, upwards of 600 men having lost their lives, chiefly from an
insidious internal malady not then understood. But the great financial success of
this international tunel has been so marked, as to justify the proposed construction
of a still longer tunnel under the Simplon.

The arrangements which are to be adopted for securing the health of the
employés ave admirable, and will surely not only result in reducing the death rate
toa minimum, but also tend to shorten the time necessary for the execution of the
undertaking to one-half.

The quantity of air to be forced into the workings will be twenty times greater than

TRANSACTIONS OF SECTION G. 7

in previous works. Special arrangements are devised for reducing the temperature of
the air by many degrees, suitable houses are to be provided for the men, with excel-
lent arrangements for enabling them to change their mining clothes, wet with the
water of the tunnel, before coming in contact with the Alpine cold; every man
will have a bath on leaving ; his wet clothes will be taken care of by a custodian,
and dried ready for his return to work ; suitable meals of wholesome food will be
provided, and he will be compelled to rest for half-an-hour on emerging from the
tunnel, in pleasant rooms furnished with books and papers. This may appear to
some as excessive care; but kind and humane treatment of men results, not only
in benefit to them, but also in substantial gain to those employing them, and the
endeavour of our own authorities, and of Parliament, to secure for our own work-
people the necessary protection for their lives and limbs in carrying out hazardous
trades and employments, is worthy of admiration.

The great improvements in sub-aqueous tunnelling can be clearly recognised
from the fact that the Thames Tunnel cost 1,150/. per lineal yard, whilst the
Blackwall Tunnel, consisting of iron lined with concrete, and of 25 feet internal
diameter, has, by means of Greathead’s shield and grouting machine, been driven
from shaft to shaft a distance of 754 yards for 375/. per yard.

Tunnels have now been successfully constructed through the most difficult strata,
such as waterbearing silt, sand, and gravel, and, by the use of grouting under pres-
sure, subsidence can almost entirely be avoided, thus rendering the piercing of the
substrata of towns, underneath property without damaging it, a simple operation ;
and opening up to practical consideration many most important lines of communi-
cation hitherto considered out of the question.

On the other hand, very little improvement has taken place in the mode of
constructing tunnels in ordinary ground, since the early days of railways. The
engineers and contractors of those days adopted systems of timbering and construc-
tion which have not been surpassed. The modern engineer is, however, greatly
assisted by the possibility of using Brindle bricks of great strength to resist pres-
sure, combined with quick-setting Portland cement, by the great improvements
which have taken place in pumping machinery, and by the use of the electric light
during construction.

A question which is forcing itself upon the somewhat unwilling attention of
our great railway companies, in consequence of the continual great increase of
the population of our cities, is the pressing necessity for a substantial increase in
the size of the terminal stations in the great centres of population.

Many of our large terminal stations are not of sutlicient capacity to be worked
properly, either with regard to the welfare of the staff, or to the convenience of the
travelling public.

Speak to station-masters and inspectors on duty, when the holiday season
is on, and they will tell you of the great physical strain that is produced upon
them and their subordinates, in endeavouring to cope with the difficulty.

This, if nothing else, is a justitication for the enterprise of the Manchester, Shef-
field and Lincolnshire Railway Company in providing an entirely new terminus
for London.

It is thirty years since the last, that of St. Pancras, was added, and during that
period the population of London has increased by no less than two millions.

The discussion, both in and out of Parliament, of the proposals for light rail-
ways has developed a considerable amount of interest in the question. Experi-
ence only can prove whether they will fulfil the popular expectations. If the
intended branch lines are to be of the standard gauge, with such gradients and
curves as will render them suitable for the ordinary rolling-stock, they will, in
many cases, not be constructed at such low mileage costs as to be likely to be
remunerative at rates that would attract agricultural traffic. The public roads of
this country (very different from the wide and level military roads of Northern
Italy and other parts of the Continent) do not usually present facilities for
their utilisation, and, once admitted, the necessity for expropriating private
Property, the time-honoured questions of frontage severances and interference
with amenities will force their way to the front, fencing will be necessary, and,

8 REPORT—1896,

even if level crossings be allowed at public roads, special precautions will have to
be taken, }

Much must then depend upon the regulations insisted upon by the Board of
Trade. If, in consideration of a reduction in speed, relaxation of existing safe-
guards are permitted, much may, no doubt, be effected by way of feeders to existing
main lines.

If, on the other hand, the branches are of narrower gauge, separate equipment
will be necessary, and transhipment at junctions will involve both expense and
delay. It is very doubtful whether the British farmer would benefit much from
short railways of other than standard gauge. He must keep horses for other pur-
poses, and he will probably still prefer to utilise them for carting his produce to the
nearest railway station of the main line, or to the market town.

The powers granted by the Light Railways Act, in the hands of the able
Commissioners appointed under the Act, cannot, however, fail to be a public boon.

Special Acts of Parliament will be unnecessary, facilities will granted,

rocedure simplified, some Government aid rendered, and probably the heavy
batten of a Parliamentary deposit will be removed.

It would seem quite probable, that motor cars may offer one practical solution of
the problem how best to place the farms of the country in commercial touch with
the trunk railways, seaports, and market towns. They could use existing roads,
could run to the tarmyard or field, and receive or deliver produce at first hand.

Such means of locometion were frequently proposed towards the end of the
last century, and in the early part of the present one, and it was not until the year
1840, that the victory of the railway over steam upon common roads was assured,
the tractive force required being then shown to be relatively as 1 to 7.

The passing of the Act of 1896, superseding those of 1861 and 1865, will
undoubtedly mark the commencement of a new era in mechanical road traction.
The cars, at present constructed chiefly by German and French engineers, are
certainly of crude design, and leave much to be desired. They are ugly in appear-
arce, noisy, difficult to steer, and vibrate very much with the revolutions of their
engines, rising as they do to 400 per minute ; those driven by oil give out offensive
odours, and cannot be readily started, so that the engine runs on during short.
stops. There would seem to be arising here an even more important opening for
the skill of our mechanical engineers than in the ease of bicycles, in which
wonderful industry the early steps appear also to have been foreign.

It is claimed for a motor car that it costs no more than carriage, horse, and
harness, that the repairs are about the same, and that, whilst a horse, travellin,
20 miles per day, represents for fodder a cost of 2d. per mile, a motor car
24 horse-power will run the same distance at $d. per mile.

The highway authorities should certainly welcome the new comer, for it is
estimated that two-thirds of the present wear and tear of roads is caused by-
horses, and one-third only by wheels.

Perhaps no inyention has had so widespreading an influence on the construction
of railways as the adoption of the Bessemer process for the manufacture of steel rails.
This has substituted a homogeneous crystalline structure, of great strength and
uniformity, for the iron rails of former years, built up by bundles of bars, and
therefore liable to lamination and defective welds. The price has been reduced
from the 13/. per ton, which iron rails once reached, to 8/. 15s. as a minimum for
steel. There are, however, not infrequently occurring, in the experience of rail-
way companies, the cracking, and eyen fracture of steel rails, and the Government
has lately appointed a Board of Trade Committee for the investigation, inciden-
tally of this subject, but specially of the important question of the effect of fatigue
upon the crystallisation, structure, and strength, of the rail. Experience proves, at
any rate, that it is of great importance to remove an ample length of crop end, as
fractures more frequently take place near the ends, aided by the weakening caused
by bolt holes. Frequent examination by tapping, as in the case of tyres, seems, at
present, the most effective safeguard.

It is open to serious question, whether the great rigidity of the permanent way
of the leading railways of this country is an advantage. Certainly the noise is

TRANSACTIONS OF SECTION G. 9

very great, more so than in other countries, and this points to severe shocks, heavy
wear and tear of rails and tyres, and—especially when two heavy locomotives are
run with the same train—liability to fracture. Whilst the tendency in this
country, and in the United States, has been to gradually increase the weight of
rails from 40 lbs. up to 100 Ibs. per lineal yard, there are engineers who think that
to decrease the rigidity of rail ath fishplate, and weight of chair, and to increase the
sleepers, so as to arrive as nearly as possible at a continuous bearing, would result
in softness and smoothness of running.

The average and maximum speeds now attained by express trains would appear
to have reached the limit of safety, at any rate nnder the existing conditions of
junctions, cross-over roads, and other interferences with the continuity of the rail.

f higher speeds are to be sought, it would seem to be necessary to have isolated
trunk lines, specially arranged in all their details, free from sharp curve and severe
gradient, and probably worked electrically, although a speed of 100 miles per hour
is claimed to have been reached by a steam locomotive in the United States.

The grain trade of the port of Liverpool has assumed very large proportions,
and the system of storage in large silos has been adopted, with great advantage,
both as regards capital, outlay, and the cost of working, per ton of grain.

The Liverpool Grain Storage Warehouses at Bootle will be open to Members
of the Association, and there can be seen the latest development of the mechanical
unloading, storing and distribution of grain in bulk ; the capacity is large, being :—

Warehouse No. 1, 56,000 tons
. » 2,380,000 ,, or 4,240,000 bushels
Quay Stores 20,000 ,,

thus constituting this granary as one of the largest, if not the largest, in the
world.

The question of the pressure of grain is a very difficult one, and, in constructing
the brick silos, which are 12 feet across at the top, by nearly 80 feet in depth, large
allowance has been made both for ordinary pressure, and for possible swelling of
the grain.

The grain is unloaded by elevators, and then transported on bands, the result
being its cooling and cleansing, as well as its storage and distribution.

he question of the early adoption in England of the metric system is of im-
ortance not only to the engineering profession, but also to the country at large.
he recommendation of the recent Royal Commission, appointed for the consideration

of the subject, was, that it should be taught at once in all schools, and that, in two
years’ time, its adoption should be compulsory ; but it is much to be regretted that,
up to the present time, nothing has been done.

The slight and temporary inconvenience of having to learn the system is of no
moment compared to the great assistance it would prove to the commercial and
trading world; the simplification of calculations and of accounts would be hailed
with delight by all so soon as they realised the advantages. England is suffering
greatly in her trade with the Continent for want of it.

Our foreign customers, who have now used it for many years, will not tolerate
the inconvenience of the endless variety of weights and measures in use in
England, and they consequently purchase their goods, to a great extent, from
Germany, rather than use our antiquated English system. It is no exaggeration to
say that, with their knowledge of the metric system, they regard ours as completely
obsolete and unworkable, just in the same way as we should were we to buy our
corn, our wine, our steel and iron, by the hin, the ephah, or the homer, or to
compute our measurements by cubit, stadium, or parasang.

Tt behoves all who desire to see England regain her trade to use all their
influence in favour of the adoption of this system, as its absence is, doubtless, one
of the contributory causes for the loss that has taken, and is taking, place.

An important argument in favour of the metric system of weights and measures
is that it is adopted all over the civilised world by physicists and chemists; and it
may be stated with confidence, that the present international character of these
sciences is largely due to this,

10 REPORT—1896,

It is interesting also to notice, that the metric system is being gradually intro-
duced into other branches of science. Anthropometric measurements made by the
Committees of the British Association in this country and in Canada are invariably
given in metres, and a comparison with measurements made in other countries can
be at once made.

The period of twenty-five ae under review has indeed witnessed great
advances, both in scientific knowledge and practical application. This progress has
led to powerful yet peaceful competition between the leading nations. Both from
among our cousins of the United States, and from our nearer neighbours of
Europe, have we, at this Meeting, the pleasure of welcoming most respected repre-
sentatives. But their presence, and the knowledge of the great discoveries made,
and colossal works carried out, by them and their brother scientists and engineers,
must make us of Great Britain face with increased earnestness the problem of
maintaining our national position, at any rate, in the forefront of all that tends
towards the ‘ utilisation of the great sources of power in Nature for the use and
convenience of man.’ Those English engineers who have been brought in contact
with engineering thought and action in America and abroad have been impressed
with the thoroughness of much of the work, the great power of organisation, and
the careful reliance upon scientific principles constantly kept in view, and upon
chemical and mechanical experiments, carried out often upon a much more
elaborate scale than in this country. This is not the place from which to discuss
the questions of bounties and tariffs, which have rendered possible powerful com-
petition for the supply of machinery and railway plant from the Continent to our
own Colonies; but there is certainly need for advance all along the line of mechani-
cal science and practice, if we are to hold our own—need especially to study the
mechanical requirements of the world, ever widening and advancing, and to be
ready to meet them, by inventive faculty first, but also by rigid adherence to
sound principles of construction, to the use of materials and workmanship of the
highest class, to simplicity of design and detail, and to careful adaptation of our
productions to the special circumstances of the various markets.

It is impossible to forecast in what direction the great advances since 1871 will
be equalled and exceeded in the coming quarter of a century. Progress there will-
and must be, probably in increased ratio; and some, at the end of that period, ma:
be able to look back upon our gathering here in Liverpool in 1896 as dealing wi
subjects then long since left behind in the race towards perfection.

The mechanical engineer may fairly hope for still greater results in the per-
fection of machinery, the reduction of friction, the economical use of fuel, the
substitution of oil for coal as fuel in many cases, and the mechanical treatment
of many processes still dependent upon the human hand.

The electrical engineer (hampered as he has been in this country by unwise
and retrograde legislation) may surely look forward to a wonderful ee in’
the use of that mysterious force, which he has already learned so wonderfully to
control, especially in the direction of traction.

The civil engineer has still great channels to bridge or tunnel, vast communi-
ties to supply with water and illuminating power, and (most probably with the
assistance of the electrician) far higher speeds of locomotion to attain. He has
before him vast and ever-increasing problems for the sanitary benefit of the world,
and it will be for him to deal from time to time with the amazing internal traffic
of great cities. China lies before him, Japan welcomes all advance, and Africa is
great with opportunities for the coming engineers. ;

Let us see to it, then, that our rising engineers are carefully educated and
prepared for these responsibilities of the future, and that our scientific brethren
may be ever ready to open up for them by their researches fresh vistas of possibili-
ties, fresh discoveries of those wonderful powers and facts of Nature which man
to all time will never exhaust.

The Mechanical Section of the British Association has done good work in this
direction in the past, and we may look forward with confidence to our younger
brethren to maintain these traditions in the future.

Brifish Associafion for fhe Advancement of
Science.

LIVERPOOL, 1896.

ADDRESS

TO THE

ANTHROPOLOGICAL SECTION,

BY

ARTHUR J. EVANS, M.A, FS.A.,
PRESIDENT OF THE SECTION.

‘The Eastern Question’ in Anthropology.

TRAVELLERS have ceased to seek for the ‘Terrestrial Paradise,’ but, in a broader
sense, the area in which lay the cradle of civilised mankind is becoming generally
recognised. The plateaux of Central Asia have receded from our view. Antbropo-
logical researches may be said to have established the fact that the White Race, in
the widest acceptation of the term, including, that is, the darker-complexioned
section of the South and West, is the true product of the region in which the
earliest historic records find it concentrated. Its ‘ Area of Characterisation’ is
conterminous, in fact, with certain vast physical barriers due to the distribution of
sea and land in the latest geological period. The continent in which it rose, shut in
between the Atlantic and the Indian Oceans, between the Libyan Desert, and
what is now Sahara, and an icier Baltic stretching its vast arms to the Ponto-
Caspian basin, embraced, together with a part of anterior Asia, the greater part of
Europe, and the whole of Northern Africa The Mediterranean itself—divided
into smaller separate basins, with land bridges at the Straits of Gibraltar, and
from Sicily and Malta to Tunis—did not seriously break the continuity of the
whole. The English Channel, as we know, did not exist, and the old sea-coast of
what are now the British Islands, stretching far to the west, is, as Professor
Boyd Dawkins has shown, approximately represented by the hundred-fathom line.
To this great continent Dr. Brinton, who has so ably illustrated the predominant
part played by it in isolating the white from the African black and the yellow
races of mankind, has proposed to give the useful and appropriate name of
‘Burafrica.’ In ‘ Eurafrica, in its widest sense, we find the birthplace of the
highest civilisations that the world has yet produced, and the mother country of
its dominant peoples.

It is true that later geological changes have made this continental division no
longer applicable. The vast land area has been opened to the east, as if to invite
the Mongolian nomads of the seppes and Tundras to mingle with the European
population ; the Mediterranean bridges, on the other hand, have been swept away.
Asia has advanced, Africa has receded. Yet the old underlying connexion of the
peoples to the north and south of the Mediterranean basin seems never to have
been entirely broken. Their inter-relations affect many of the most interesting
phenomena of archeology and ancient history, and the old geographical unity of
‘ Eurafrica’ was throughout a great extent of its area revived in the great political
system which still forms the basis of civilised society, the Roman Empire. The
Mediterranean was a Roman lake. A single fact brings home to us the extent to

H

2 REPORT—1896.

which the earlier continuity of Europe and North Africa asserted itself in the
imperial economy. At one time, what is now Morocco and what is now
Northumberland, with all that lay between them on both sides of the Pyrenees,
found their administrative centre on the Mosel.

It is not for me to dwell on the many important questions affecting the physio-
logical sides of ethnography that are bound up with these old geographical relniaag
I will, however, at least call attention to the interesting, and in many ways
original, theory put forward by Professor Sergi in his recent work on the ‘ Mediter-
ranean Race.’

Professor Sergi is not content with the ordinary use of the term ‘ White Race.’ —
He distinguishes a distinct ‘ brown’ or ‘brunette’ branch, whose swarthier com-
lexion, however, and dark hair bear no negroid affinities, and are not due to an:

intermixture on that side. This race, with dolichocephalic skulls, amongst whi
certain clearly defined types constantly repeat themselves, he traces throughout
the Mediterranean basin, from Hgypt, Syria, and Asia Minor, through a large part
of Southern Europe, including Greece, Italy, and the Iberic peninsula, to the
British islands. It is distributed along the whole of North Africa, and, according
to the theory propounded, finds its original centre of diffusion somewhere in the
parts of Somaliland. :

It may be said at once that this grouping together into a consistent system of
ethnic factors spread over this vast yet inter-related area—the heart of ‘ Eurafrica’—
presents many attractive aspects. The ancient Greek might not have accepted
kinship even with ‘the blameless Ethiopian,’ but those of us who may happen
to combine a British origin with a Mediterranean complexion may derive a certain
ancestral pride from remote consanguinity with Pharaoh. They may even be
willing to admit that ‘the Ethiopian’ in the course of his migrations has done
much to ‘change his skin.’

In part, at least, the new theory is little more than a re-statement of an ethno-
graphic grouping that commands a general consensus of opinion, From Thurnam’s
time onwards we have been accustomed to regard the dolichocephalic type found in
the early Long Barrows, and what seem to have been the later survivals of the
same stock in our islands, as fitting on to the Iberian element in South-western
Europe. The extensive new materials accumulated by Dr. Garson have only served
to corroborate these views, while further researches have shown that the character-
istic features of the skeletons found in the Ligurian caves, at Cro Magnon and
elsewhere in France, are common to those of a large part of Italy, Sicily, and
Sardinia, and extend not only to the Iberiec group, but to the Guanche interments
of the Canary Islands.

The newly correlated data unquestionably extend the field of comparison; but
the theories as to the original home of this ‘ Mediterranean race’ and the course
of its diffusion may be thought to be still somewhat lacking in documentary
evidence. They remind us rather too closely of the old ‘Aryan’ hypothesis, in
which we were almost instructed as to the halting places of the different detach-
ments as they passed on their way from their Central Asian cradle to rearrange
themselves with military precision, and exactly in the order of their relationship,
in their distant European homes. The existing geological conditions are tie
the basis of this migratory expansion from Ethiopia to Ireland; parallel streams
move through North Africa and from Anatolia to Southern Europe. One cardinal
fact has certainly not received attention, and that is, that the existing evidence of
this Mediterranean type dates much further back on European soil than even in
ancient Egypt.

Professor Sergi himself has recognised the extraordinary continuity of the
cranial type of the Ligurian caves among the modern population of that coast.

But this continuity involves an extreme antiquity for the settlement of the
‘ Mediterranean Race’ in North-western Italy aa Southern France. The cave
interments, such as those of the Finalese, carry back the type well into Neolithic —
times. But the skeletons of the Baoussé Roussé caves, between Mentone and
Ventimiglia, which reproduce the same characteristic forms, take us back far
behind any stage of culture to which the name of Neolithic can be properly applied.

TRANSACTIONS OF SECTION H. 3

The importance of this series of interments is so unique, and the fulness of the
evidence so far surpasses any other records immediately associated with the earliest
remains of man, that even in this brief survey they seem to demand more than a
passing notice.

So much, at least, must be admitted on all hands: an earlier stage of culture is
exhibited in these deposits than that which has hitherto been regarded as the mini-
mum equipment of the men of the later Stone Age. The complete absence of

ottery, of polished implements, of domesticated animals—all the more striking
rom the absolute contrast presented by the rich Neolithic cave burials a little
further up the same coast —how is it to be explained? The long flint knives, the
bone and shell ornaments, might, indeed, find partial parallels among Neolithic
remains ; but does not, after ull, the balance of comparison incline to that more
ancient group belonging to the ‘ Reindeer Period’ in the South of France, as illus-
rated by the eaves of La Madeleine, Les Eyzies and Solutré ?

It is true that, in an account of the interments found in 1892 in the Barma
Grande Cave, given by me to the Anthropological Institute, I was myself so pre-
possessed by the still dominant doctrine that the usage of burial was unknown to
Paleolithic man, and so overpowered by the vision of the yawning hiatus between
him and his Neolithic successor, that I failed to realise the full import of the
evidence. On that occasion I took refuge in the suggestion that we had here to
deal with an earlier Neolithic stratum than any hitherto recorded. ‘ Neolithic,’
that is, without the Neolithic.

But the accumulation of fresh data, and especially the critical observations of
M. d’Acy and Professor Issel, have convinced me that this intermediate position is
untenable. From the great depth below the original surface, of what in all cases
seem to have been homogeneous quaternary deposits, at which the human remains
were found, it is necessary to suppose, if the interments took place at a later
period, that pits in many cases from 30 to 40 feet deep must have been excavated in
’ the cave earth. But nothing of the kind has been detected, nor any intrusion of
extraneous materials. On the other hand, the gnawed or defective condition of the
extremities in several cases points clearly to superficial and imperfect interment of
the body; and in one case parts of the same core from which flints found with the
skeleton had been chipped were found some metres distant on the same floor level.
Are we, then, to imagine that another pit was expressly dug to bury these ?

In the case of a more recently discovered and as yet unpublished interment, at
the excavation of which I was so fortunate as to assist, the superficial character of
the deposit struck the eye. The skeleton, with flint knife and ochre near, decked
out with the usual shell and deer’s tooth ornaments, lay as if in the attitude of
sleep, somewhat on the left side. The middle of the body was covered with a lar
flat stone, with two smaller ones lying by it, while another large stone was laid
over the feet. The left arm was bent under the head as if to pillow it, but the
extremities of the right arm and the toes were suggestively deficient : the surface
covering of big stones had not sufficiently protected them. The stones themselves
seem in turn to have served as a kind of hearth, for a stratum of charred and
burned bones about 45 em. thick lay about them.

Is it reasonable to suppose that a deposit of this kind took place at the bottom
ofa pit over 20 feet deep, left open an indefinite time for the convenience of
roasting venison at the bottom ?

A rational survey of the evidence in this asin the other cases leads to the conclu-
sion that we have to deal with surface burial, or, if that word seems too strong, with
simple ‘ seposition ’—the imperfect covering with handy stones of the dead bodies
as they lay in the attitude of sleep on the then floor of the cavern. In other
words, they are zn situ in a late quaternary deposit, for which Professor Issel has
proposed the name of ‘ Meiolithie.

ut if this conclusion is to hold good, we have here on the northern coast of
the Mediterranean evidence of the existence of a late Paleolithic race, the essential
features of which, in the opinion of most competent osteological inquirers, reappear
in the Neolithic skeletons of the same Ligurian coast, and still remain characteristic
of the historical Ligurian type. In other words, the ‘ Mediterranean Race’ finds

H2

4 REPORT—1896.

its first record in the West; and its diffusion, so far from having necessarily
followed the lines of later geographical divisions, may well have begun at a time
when the land bridges of ‘ Eurafrica’ were still unbroken. :

There is nothing, indeed. in all this to exclude the hypothesis that the original
expansion took place from the East African side, That the earliest homes of
primeval man lay in a warm region can hardly be doubted, and the abundant
discovery by Mr. Seton Karr in Somaliland of Paleolithic implements reproducing
many of the most characteristic forms of those of the grottoes of the Dordogne
affords a new link of connexion between the Red Sea and the Atlantic littoral.

When we recall the spontaneous artistic qualities of the ancient race which has
left its records in the carvings on bone and ivory in the caves of the ‘ Reindeer
Period,’ this evidence of at least partial continuity on the northern shores of the
Mediterranean suggests speculations of the deepest interest. Overlaid with new
elements, swamped in the dull, though materially higher, Neolithic civilisation,
may not the old wsthetic faculties which made Europe the earliest-known home of
unything that can be called human art, as opposed to mere tools and mechanical
contrivances, have finally emancipated themselves once more in the Southern
regions, where the old stock most survived? In the extraordinary manifestations
of artistic genius to which, at widely remote periods, and under the most diverse
political conditions, the later populations of Greece and Italy have given birth, may
we not be allowed to trace the re-emergence, as it were, after long underground
meanderings, of streams whose upper waters had seen the daylight of that earlier
world ? : ‘

But the vast gulf of time beyond which it is necessary to carry back our gaze
in order to establish such connexions will hardly permit us to arrive at more
than vague probabilities. The practical problems that concern the later culture
of Europe from Neolithic times onwards connect themselves rather with its relation
to that of the older civilisations on the southern and eastern Mediterranean shores,

Anthropology, too, has its ‘ Eternal Eastern Question.’ Till within quite
recent years, the glamour of the Orient pervaded all inquiries as to the genesis
of European civilisation. The Biblical training of the northern nations prepared
the ground. The imperfect realisation of the antiquity of European arts; on the
other hand, the imposing chronology of Egypt and Babylonia; the abiding force
of classical tradition, which found in the Phoenician a deus ex machind for
exotic importations; finally, the ‘Aryan Hypothesis, which brought in the
dominant European races as immigrant wanderers from Central Asia, with a
ready-made stock of culture in their wallets—these and other causes combined to
create an exaggerated estimate of the part played by the Hast as the illuminator of
the benighted West.

More recent investigations have resulted in a natural reaction. The primitive
‘ Aryan’ can be no longer invoked as a kind of patriarchal missionary of Central
Asian culture. From d’Halloy and Latham onwards to Penka and Schrader an
array of eminent names has assigned to him an European origin. The means by
which a kindred tongue diffused itself among the most heterogeneous ethnic
factors still remain obscure; but the stricter application of phonetic laws and
the increased detection of loan-words has cut down the original ‘ Aryan’ stock of
culture to very narrow limits, and entirely stripped the members of this linguistic
family of any trace of a common Pantheon.

Whatever the character of the original ‘ Aryan’ stage, we may be very sure
that it lies far back in the mists of the European Stone Age. The supposed
common names for metals prove to be either a vanishing quantity or strikingly
irrelevant. It may be interesting to learn on unimpeachable authority that the
Celtic words for ‘gold’ are due to comparatively recent borrowing from the Latin;
but nothing is more certain than that gold was one of the earliest metals known
to the Celtic races, its knowledge going back to the limits of the pure Stone Age.
We are told that the Latin ‘ensis, ‘a sword,’ is identical with the Sanskvit ‘asi’
and Iranian ‘ahi, but the gradual evolution of the sword from the dagger, only
completed at a late period of the Bronze Age, is a commonplace of prehistoric
archeology. If ‘ensis,’ then, in historical times an iron sword, originally meant a

TRANSACTIONS OF SECTION H. »

bronze dagger, may not the bronze dagger in its turn resolve itself into a flint
knife ?

The truth is that the attempts to father on a common Aryan stock the
beginnings of metallurgy argue an astonishing inability to realise the vast
antiquity of languages and their groups. Yet we know that, as far back as we
have any written records, the leading branches of the Aryan family of speech
stood almost as far apart as they do to-day, and the example of the Egyptian and
Semitic groups, which Maspero and others consider to have been originally con-
nected, leads to still move striking results. From the earliest Egyptian stela to
the latest Coptic liturgy we find the main outlines of what is substantially the
same language preserved for a period of some six thousand years. The Semitic
languages in their characteristic shape show a continuous history almost as ex-
tensive. For the date of the diverging point of the two groups we must have
recourse to a chronology more familiar to the geologist than the antiquary.

As importer of exotic arts into primitive Europe the Phoenician has met the
fate of the immigrants from the Central Asian ‘ Arya.’ The days are gone past
when it could be seriously maintained that the Phoenician merchant landed on the
coast of Cornwall, or built the dolmens of the North and West. A truer view of
many trade as passing on by inter-tribal barter has superseded the idea of a

irect commerce between remote localities. The science of prehistoric archeology,
following the lead of the Scandinavian School, has established the existence in
every province of local centres of early metallurgy, and it is no longer believed that
the implements and utensils of the European Bronze Age were imported wholesale
by Semites or ‘ Etruscans.’

It is, however, the less necessary for me to trace in detail the course of this re-
action against the exaggerated claims of Hastern influence that the case for the
independent position of primitive Nurope has been recently summed up with fresh
arguments, and in his usual brilliant and incisive style, by M. Salomon Reinach, in
his *‘ Mirage Orientale. For many ancient prejudices as to the early relations of
East and West it is the trumpet sound before the walls of Jericho. It may, indeed,
be doubted whether, in the impetuousness of his attack, M. Reinach, though he has
rapidly brought up his reserves inhis more recent work on primitive European
sculpture, has not been tempted to occupy outlying positions in the enemy’s country
which will hardly be found tenable in the long run. I cannot myself, for instance,
be brought to believe that the rude marble ‘ idols’ of the primitive “Zgean popula-
tion were copied on Chaldean cylinders. I may have occasion to point out that the
oriental elements in the typical higher cultures of primitive Europe, such as those of
Mycene, of Hallstatt, and La Téne, are more deeply rooted than M. Reinach will
admit. But the very considerable extent to which the early European civilisation
was of independent evolution has been nowhere so skilfully focussed into light as in
these comprehensive essays of M. Reinach. It is always a great gain to have the
extreme European claims so clearly formulated, but we must still remember that
the ‘Sick Man’ is not dead.

The proofs of a highly developed metallurgic industry of home growth accu-
mulated by prehistoric students par? passu over the greater nh of Europe, and the
considerable cultural equipment of its early population—illustrated, for example,
in the Swiss Lake settlements—had already prepared the way for the more start-
ling revelations as to the prehistoric civilisation of the A2gean world which have
resulted from Dr. Schliemann’s diggings at Troy, Tiryns, and Mycenm, so admirably
followed up by Dr. Tsountas.

This later civilisation, to which the general name of ‘ gean’ has been given,
shows several stages, marked in succession by typical groups of finds, such as those
from the Second City of Troy, from the cist-graves of Amorgos, from beneath the
voleanic stratum of Thera, from the shaft-graves of Mycenee, and again from the
tombs of the lower town. Roughly, it falls into two divisions, for the earlier of
which the culture illustrated by the remains of Amorgos may be taken as the
ae point, while the later is inseparably connected with the name of

yeene.

The early ‘ Aigean’ culture rises in the midst of a vast province extending from

6 REPORT—1896,

Switzerland and Northern Italy through the Danubian basin and the Balkan

ninsula, and continued through a large part of Anatolia, till it finally reaches

yprus. It should never be left out of sight that, so far as the earliest historical
tradition and geographical nomenclature reach back, a great tract of Asia Minor
is found in the occupation of men of European race, of whom the Phrygians and
their kin—closely allied to the 'Thracians on the other side of the Bosphorus—
stand forth as the leading representatives. Qn the other hand, the great antiquity
of the Armenoid type in Lycia and other easterly parts of Asia Minor, and its
priority to the Semites in these regions, has been demonstrated by the craniological
researches of Dr. von Luschan. This ethnographic connexion with the European
stock, the antiquity of which is carried back by Egyptian records to the second
millennium before our era, is fully borne out by the archeological evidence. Very
similar examples of ceramic manufactures recur over the whole of this vast region.
The resemblances extend even to minutiz of ornament, as is well shown by the
examples compared by Dr. Much from the Mondsee, in Upper Austria, from the
earliest stratum of Hissarlik, and from Cyprus. It is in the same Anatolo-Danubian
area—as M, Reinach has well pointed out—that we find the original centre of
diffusion of the ‘Svastika’ motive in the Old World. Copper implements, and
weapons too, of primitive types, some reproducing Neolithic forms, are also a
common characteristic, though it must always be remembered that the mere fact
that an implement is of copper does not of itself necessitate its belonging to the
earliest metal age, and that the freedom from alloy was often simply due to a tem-
porary deficiency of tin. Cyprus, the land of copper, played, no doubt, a leading
part in the dissemination of this early metallurgy, and certain typical pins and other
objects found in the Alpine and Danubian regions have been traced back by Dr.

Naue and others to Cypriote prototypes. The same parallelism throughout this

vast area comes out again in the appearance of a class of primitive ‘idols’ of clay,
marble, and other materials, extending from Cyprus to the Troad and the A%gean
islands, and thence to the pile settlements of the Alps and the Danubian basin,

while kindred forms can be traced beyond the Carpathians to a vast northern

Neolithic province that stretches to the shores of Lake Ladoga.

It is from the centre of this old Anatolo-Danubian area of primitive culture, in
which Asia Minor appears as a part of Europe, that the new Jgean civilisation
rises from the sea. ‘Life was stirring in the waters.’ ‘The notion that the
maritime enterprise of the Eastern Mediterranean began on the exposed and
comparatively harbourless coast of Syria and Palestine can no longer be main-
tained. The island world of the 4Jgean was the natural home of primitive navi-
gation. The early sea-trade of the inhabitants gave them a start over their
neighbours, and produced a higher form of culture, which was destined to react on
that of a vast European zone—nay, even upon that of the older civilisations of
Egypt and Asia. f

The earlier stage of this Aigean culture culminates in what may conveniently
be called the Period of Amorgos from the abundant tombs explored by Dr. Diimm-
ler and others in that island. Here we already see the proofs of a widespread
commerce. The ivory ornaments point to the South ; the abundance of silver may
even suggest an intercourse along the Libyan coast with the rich silver-producing
region of South-eastern Spain, the very ancient exploitation of which has been so
splendidly illustrated by the researches of the brothers Siret. Additional weight
is lent to this presumption by the recurrence in these Spanish deposits of pots with
rude indications of eyes and eyebrows, recalling Schliemann’s owl-faced urns; of
stone ‘idols,’ practically identical with those of Troy and the Aigean islands, here too
associated with marble cups of the same simple forms; of triangular daggers of
copper and bronze, and of bronze swords which seem to stand in a filial relation to
an‘Amorgan’ type of dagger. In a former communication to this Section I
ventured to see in the so-called ‘Cabiri’ of Malta—very far removed from any
Phcenician sculpture—an intermediate link between the Iberian group and that of
the Aigean, and to trace on the fern-like ornaments of the altar-stone a comparison

with the naturalistic motives of proto-Mycenean art, as seen, for instance, on the

early vases of Thera and Therasia.

»

TRANSACTIONS OF SECTION H. 7

A Chaldean influence cannot certainly be excluded from this early Aigean
art. It reveals itself, for instance, in indigenous imitations of Babylonian cylinders.
My own conclusion that the small marble figures of the A%gean deposits, though
of indigenous European lineage, were in their more developed types influenced by
Istar models from the East, has since been independently arrived at by the Danish
archeologist, Dr. Blinkenburg, in his study on prae-Mycenzan art.

More especially the returning-spiral decoration, which in the ‘ Amorgan Period’
appears upon seals, rings, bowls, and caskets of steatite, leads us to a very interest-
ing field of comparison. his motive, destined to play such an important part in
the history of Muropean ornament, is absent from the earlier products of the great
Anatolo-Danubian province. As a European design it is first found on these
insular fabrics, and it is important to observe that it first shows itself in the form
of reliefs on stone. The generally accepted idea, put forward by Dr. Milchhotler,
that it originated here from applied spirals on metal work is thus seen to be bereft
of historical justification. At a somewhat later date we find this spiraliform
motive communicating itself to the ceramic products of the Danubian region,
though from the bold relief in which it sometimes appears, a reminiscence of the
earlier steatite reliefs seems still traceable. In the late Neolithic pile-station of
Butmir, in Bosnia, this spiral decoration appears in great perfection on the pottery,
and is here associated with clay images of very advanced fabric. At Lengyel, in
Hungary, and elsewhere, we see it applied to primitive painted pottery. Finally,
in the later Hungarian Bronze Age it is transferred to metal work.

But this connexion—every link of which can be made out—of the lower
Danubian Bronze Age decoration with the gean spiral system—itself much
earlier in origin—has a very important bearing on the history of ornament in the
North and West. ‘he close relation of the Bronze Age culture of Scandinavia and
North-western Germany with that of Hungary is clearly established, and of
the many valuable contributions made by Dr. Montelius to prehistoric archeology,
none is more brilliant than his demonstration that this parallelism of culture
between the North-west and South-east owes its origin to the most ancient
course of the amber trade from the North Sea shores of Jutland by the valley
of the Elbe and Moldau to the Danubian Basin. As Dr. Montelius has also
shown, there was, besides, a western extension of this trade to our own islands,
If Scandinavia and its borderlands were the source of amber, [reland was the land
of gold. The wealth of the precious metal there is illustrated by the fact
that, even as late as 1796, the gold washings of County Wicklow amounted to
10,0007. A variety of evidence shows a direct connexion between Great Britain
and Seandinavia from the end of the Stone Age onwards. Gold diadems of
unquestionably British—probably Irish—fabric have been found in Seeland and
Fiinen, and from the analysis of early gold ornaments it clearly results that it was
from Ireland rather than the Ural that Northern and Central Europe was supplied.
Mr. Coffey, who has made an exhaustive study of the early Irish monuments,
has recently illustrated this early connexion by other comparisons, notably the
appearance of a design which he identifies with the early caryings of boats on the
rocks of Scandinavia.

This prolongation of the Bronze Age trade route—already traced from the
Middle Danube—from Scandinavia to Ireland, ought it to be regarded as the
historic clue to the contemporary appearance of the spiral motive in the British
Islands? Is it to this earlier intercourse with the land of the Vikings that we
must ascribe the spiral scrolls on the slabs of the great chambered barrows of the
Irish Bronze Age—best seen in the most imposing of them all, before the portal
and on the inner chambers of New Grange ?

The possibility of such a connexion must be admitted; the probability is great
that the contemporary appearance of the spiraliform ornament in Ireland and on the
Continent of Europe is due to direct derivation. It is, of course, conceivable that
such a simple motive as the returning spiral may have originated independently
in various parts of Lurope, as it did originate in other parts of the world. But
anthropology has ceased to content itself with the mere accumulation of sporadic
coincidences. It has become a historic study. It is not sutlicient to know how

8 REPORT—1896.

such and such phenomena may have originated, but how, as a matter of fact, they
did. Uence in the investigation of origins and evolution the special value of the
European field where the evidence has been more perfectly correlated and the
continuous records go further back. An isolated example of the simple yolute
design belonging to the ‘Reindeer Period’ has been found in the grotto of
Arudy. But the earliest cultural strata of Europe, from the beginning of the
Neolithic period onwards, betray an entire absence of the returning spiral motive.
When we find it later propagating itself as a definite ornamental system in a
regular chronological succession throughout an otherwise inter-related European
zone, we have every right to trace it to a common source.

But it does not therefore follow that the only alternative is to believe that the
spiral decoration of the Irish monuments necessarily connects itself with the
ancient stream of intercourse flowing from Scandinavia.

We have to remember that the Western lands of gold and tin were the goals
of other prehistoric routes. Especially must we bear in mind the early evidence
of intercourse between the British Isles and the old Iberic region of the opposite
shores of the Continent. The derivation of certain forms of Bronze Age types in
Britain and Ireland from this side has already been demonstrated by my father,
and British or Irish bronze flat axes with their characteristic ornamentation have
in their turn been found in Spain as well asin Denmark. The peculiar technique
of certain Irish flint arrowheads of the same period, in which chipping and grind-
ing are combined, is also characteristic of the Iberian province, and seems to lead
to very extended comparisons on the Libyan side, recurring as it does in the
exquisite handiwork of the non-Egyptian race whose relics Mr. Petrie has brought
to light at Nagada. In prehistoric Spanish deposits, again, are found the actual
wallet-like baskets with in-curving sides, the prototypes of a class of clay food-
vessels which (together with a much wider distribution) are of specially frequent
occurrence in the British Isles as well as the old Iberian area.

If the spiral decoration had been also a feature of the Scandinavian rock
carvings, the argument for derivation from that side would have been strong. —
But they are not found in them, and, on the other hand, the sculptures on the
dolmens of the Morbihan equally show certain features common to the Irish stone
chambers, including the primitive ship figure. The spiral itself does not appear cn
these ; but the more the common elements between the Megalithic piles, rot only
of the old Iberian tract on the mainland, including Brittany, but in the islands of

the West Mediterranean basin, are realised, the more probable it becomes that the y

impulse came from this side, The prehistoric buildings of Malta, hitherto spoken
of as ‘Pheenician temples, which show in their primitive conception a great
affinity to the Megalithic chambers of the earliest British barrows, bear witness
on this side to the extension of the Aigean spiral system in a somewhat
advanced stage, and accompanied, as at New Grange, with intermediate lozenges.
In Sardinia, as I hope to show, there is evidence of the former existence of monu-
ments of Mycenan architecture in which the chevron, the lozenge, and the spiral
might have been seen associated as in Ireland. It is on this line, rather than on the
Danube and the Elbe, that we find in a continuous zone that Cyclopean tradition
of domed chambers which is equally illustrated at Mycenze and at New Grange.

These are not more thau indications, but they gain additional force from the
converging evidence to which attention has already been called of an ancient line
of intercourse, mainly, we may believe, connected with the tin trade between the
East Mediterranean basin and the Iberian West. A further corroboration of the
view that an A2gean impulse propagated itself as far as our own islands from that
side is perhaps afforded be a very remarkable find in a British barrow.

I refer to the Bronze Age interment excavated by Canon Greenwell on Folkton
Wold, in Yorkshire, in which, beside the body of a child, were found three carved
chalk objects resembling round boxes with bossed lids. On one of these lids were
grouped together, with a lozenge-shaped space between them, two partly spirali-
form partly concentric circular ornaments, which exhibit before our eyes the —
degeneration of two pairs of returning spiral ornaments. Upon the sides of two of
these chalk caskets, associated with chevrons, saltires, and lozenges, were rude

TRANSACTIONS OF SECTION H. 9

indications of faces—eyes and nose of bird-like character—curiously recalling the
early Aigean and Trojan types of Dr. Schliemann. These, as M. Reinach has

ointed out, also find an almost exact parallel in the rude indications of the human
face seen on the sculptured menhirs of the Marne and the Gard valleys. To this
may be added the interesting comparisons supplied by certain clay vessels, of
rounded form, somewhat resembling the chalk ‘caskets’ discovered by MM.
Siret in Spanish interments of the early metal age, in which eyes and eyebrows of
a primitive style are inserted, as on the British relics, in the inter-spaces of linear
ornamentation. The third chalk dise exhibits, in place of the human face, a
butterfly with volute antenne, reminding us of the appearance of butterflies as a
decorative motive on the gold roundels trom the shaft-graves of Mycene, as also
on early Mycenzean gems of steatite from Crete ; in the latter case with the feelers
curving outwards in the same way. The stellate design with central circles on the
lid of one of the chalk caskets is itself not impossibly a distant degeneration of the
star-flowers on the same Mycenan plates. Putting all these separate elements of
resemblance together—the returning spiral and star, the rude face and butterfly—
the suggestion of /Sgean reminiscence becomes strong, but the other parallels lead
us for the line of its transmission towards the Iberian rather than the Scandi-
navian route.’

So much, at least, results from these various comparisons that, whether we find
the spiral motive in the extreme West or North of Europe, everything points to
the Aigean world as its first European centre. But have we any right to regard
it, even there, as of indigenous evolution ?

It had been long my own conviction that the ASgean spiral system must itself
be regarded as an offshoot of that of ancient Egypt, which as a decorative motive
on scarabs goes back, as Professor Petrie has shown, to the Fourth Dynasty.
During the time of the Twelfth Dynasty, which, on general grounds, may be sup-
posed roughly to correspond with the ‘Amorgan Period’ of Agean culture, it
attained its apogee. The spiral convolutions now often cover the whole field of the
scarab, and the motive begins to spread to a class of black bucchero vases the chall
inlaying of whose ornaments suggests widespread European analogies. But the
important feature to observe is that here, as in the case of the early Agean
examples, the original material on which the spiral ornament appears is stone, and
that, so far from being derived from an advanced type of metal work, it goes back
in Egypt to a time when metal was hardly known.

The prevalence of the spiral ornamentation on stone work in the /Egean islands
and contemporary Egypt, was it merely to be regarded as a coincidence? To turn
one’s eyes to the Nile Valley, was it simply another instance of the ‘ Mirage
Orientale’? For my own part, I ventured to believe that, as in the case of
Northern Europe, the spread of this system was connected with many collateral
symptoms of commercial inter-connexion, so here, too, the appearance of this early
/®gean ornament would be found to lead to the demonstration of a direct inter-
course between the Greek islands and Egypt at least a thousand years earlier than
any that had hitherto been allowed.

One’s thoughts naturally turned to Crete, the central island, with one face on
the Libyan Sea—the natural source and seminary of gean culture—where fresh
light was already being thrown on the Mycenzean civilisation by the researches of
Professor Halbherr, but the earlier prehistoric remains of which were still unex-
plored. Nor were these expectations unfounded. As the result of three expe-
ditions—undertaken in three successive years, from the last of which I returned
three months since—it has been my fortune to collect a series of evidences of a
very early and intimate contact with Egypt, going back at least to.the Twelfth

1 A further piece of evidence pointing in this direction is supplied by one of the
chalk ‘caskets.’ On the upper disc of this, in the place corresponding with the
double-spirals on the other example, appears a degeneration of the same motive in a
more compressed form, resembling two sets of concentric horseshoes united at their
bases. This recurs at New Grange, and single sets of concentric horseshoes, or semi-
circles, are found both there and at Gavrinnis. The degeneration of the returning
spiral motive extends therefore to Brittany.

H3

10 REPORT—1896.

Dynasty, and to the earlier half of the third millennium before our era. It is
not only that in primitive deposits, like that of Hagios Onuphrios, scarabs, acknow-
ledged by ee archeologists to be of Twelfth Dynasty date, occurred in
association with steatite seals presenting the ASgean spiral ornamentation, and
with early pottery answering to that of Amorgos and the second city of Troy.
This by itself might be regarded by many as convincing. But,—what from the
point of view of intercourse and chronology is even more important,—in the same
deposit and elsewhere occurred early button-shaped and triangular seals of steatite
with undoubted indigenous copies of Egyptian lotos designs characteristic of the
same ped, while in the case of the three-sided bead-seals it was possible to trace
a regular evolution leading down to Mycenzean times. Nor was this all. Through-
out the whole of the island there came to light a great variety of primitive stone
vases, mostly of steatite, a large proportion of which reproduced the characteristic
forms of Egyptian stone vases, in harder materials, going far back into the Ancient
Empire. ‘The returning spiral motive is also associated with these, as may be seen
from a specimen now in the collection of Dr. Naue, of Munich.

A geological phenomenon which I was able to ascertain in the course of my
recent exploration of the eastern part of the island goes far to explain the great
importance which these steatite or ‘soapstone’ fabrics played in the primitive
culture of Crete and the Augean islands. In the valley of the Sarakina stream I
came upon vast deposits of this material, the diffusion of which could be further
traced along a considerable tract of the southern coast. The abundant presence
of this attractive and, at the same time, easily workable stone—then incomparably
more valuable, owing to the imperfection of the potter’s art—goes far to explain
the extent to which these ancient Egyptian forms were imitated, and the conse-
quent spread of the returning spiral motive throughout the fBigean.

In the matter of the spiral motive, Crete may thus be said to be the missing
link between prehistoric Ireland and Scandinavia and the Egypt of the Ancient
Empire. But the early remains of the island illustrate in many other ways the
comparatively high level of culture already reached by the Aigean population in
pre-Mycenean times, Especially are they valuable in supplying the antecedent
stages to many characteristic elements of the succeeding Mycenvean civilisation.

This ancestral relationship is nowhere more clearly traceable than in a class of
relics which bear out the ancient claim of the islanders that they themselves had
invented a system of writing to which the Pheenicians did not do more than add
the finishing touches. Already, at the Oxford meeting of the Association, I was
able to call attention to the evidence of the existence ot a prehistoric Cretan script
evolved by gradual simplification and selection from an earlier picture writing.
This earlier stage is, roughly speaking, illustrated by a series of primitive seals
belonging to the ‘Period of Amorgos.’ In the succeeding Mycenwan age the —
script is more conventionalised, often linear, and though developments of the
earlier forms of seals are frequently found, they are usually of harder materials,
and the system is applied to other objects. As the result of my most recent
investigations, I am now able to announce the discovery of an inscribed pre-
historic relic, which surpasses in interest and importance all hitherto known objects
of this class. It consists of a fragment of what may be described as a steatite
‘Table of Offerings,’ bearing part of what appears to be a dedication of nine letters
of probably syllabic values, answering to the same early Cretan script that is seen
on the seals, and with two punctuations. It was obtained from the lowest level
of a Mycenzean stratum, containing numerous votive objects, in the gteat cave of
Mount Dikta, which, according to the Greek legend, was the birthplace of Zeus.

This early Cretan script, which precedes by centuries the most ancient records
of Pheenician writing, and supplies, at any rate, very close analogies to what may
be supposed to have been the pictorial prototypes of several of the Phcenician
etters, stands in a direct relation to the syllabic characters used at a later date by
the Greeks of Cyprus. The great step in the history of writing implied by the
evolution of symbols of phonetic value from primitive pictographs is thus shown
to have effected itself on European soil.

In many other ways the culture of Mycenee—that extraordinary revelation from

TRANSACTIONS OF SECTION H. ll

the soil of prehistoric Greece—can be shown to be rooted in this earlier Egean
stratum, The spiral system, still seen in much of its pure original form on the
gold vessels and ornaments from the earlier shaft-graves of Mycenw, is simply the
translation into metal of the pre-existing steatite decoration."

The Mycenean repoussé work in its most developed stage as applied to human
and eral subjects has probably the same origin in stone work. Cretan examples,
indeed, give the actual transition in which an intaglio in dark steatite is coated
with a thin gold plate impressed into the design. On the other hand, the noblest
of all creations of the Mycenzan goldsmith’s art, the Vaphio cups, with their bold
reliefs, illustrating the hunting and capture of wild bulls, find their nearest analogy
in a fragment of a cup, procured by me from Knésos, of black Cretan steatite,
with naturalistic reliefs, exhibiting a fig-tree in a sacred enclosure, an altar, and
men in high action, which in all probability was originally coated, like the intaglio,
with thin plates of gold.

In view of some still prevalent theories as to the origin of Mycenzan art, it
is important to bear in mind these analogies and connexions, which show how
deeply set its roots are in Agean soil. The Vaphio cups, especially, from their
superior art, have been widely regarded as of exotic fabric. That the art of
an European population in prehistoric times should have risen above that of
contemporary Egypt and Babylonia was something beyond the comprehension
of the traditional school. These most characteristic products of indigenous skill,
with their spirited representations of a sport the traditional home of which
in later times was the Thessalian plains, have been, therefore, brought from
‘Northern Syria’! Yet a whole series of Mycenzean gems exists executed in the
same bold naturalistic style, and of local materials, such as lapis Lacedsemonius,
the subjects of which are drawn from the same artistic cycle as those of the cups,
and not one of these has as yet been found on the Eastern Mediterranean shores.
Like the other kindred intaglios, they all come from the Peloponnese, from Crete,
from the shores and islands of the A®gean, from the area, that is, where their
materials were procured. Their lentoid and almond-shaped forms are altogether
foreign to Semitic usage, which clung to the cylinder and cone, The finer
products of the Mycenean glyptic art on harder materials were, in fact, the
outcome of long apprentice studies of the earlier A2gean population, of which we
have now the record in the primitive Cretan seals, and the explanation in the vast
beds of such an easily worked material as steatite.

But the importation of the most characteristic Mycenean products from
‘Northern Syria’ has become quite a moderate proposition beside that which we
have now before us. In a recent communication to the French Academy of
Inscriptions, Dr. Helbig has re-introduced to us a more familiar figure. Driven
from his prehistoric haunts on the Atlantic coasts, torn from the Cassiterides, dis-
lodged even from his Thucididean plantations in pre-Hellenic Sicily, the Phoenician
has returned, tricked out as the true ‘ Mycenzan.’

A great part of Dr, Helbig’s argument has been answered by anticipation.
Regardless of the existence of a regular succession of intermediate glyptic types,
such as the ‘ Melian’ gems and the engraved seals of the geometrical deposits of
the Greek mainland, like those of Olympia and of the Hermon at Argos, which
link the Myceneean with the classical series, Dr. Helbig takes a verse of Homer
to hang from it a theory that seals and engraved stones were unknown to
the early Greeks. On this imaginary fact he builds the astounding statement
that the engraved gems and seals found with Mycenean remains must be of
foreign and, as he believes, Phcenician importation. The stray diffusion of one
or two examples of Mycenean pots to the coast of Palestine, the partial re-
semblance of some Hittite bronze figures, executed in a more barbarous Syrian
style, to specimens of quite different fabric found at Tiryns, Mycenz, and, it may
be added, in a Cretan cave near Sybrita, the wholly unwarranted attribution to
Phoenicia of a bronze vase-handle found in Cyprus, exhibiting the typical lion-
headed demons of the Mycenswans—these are only a few salient examples of the

See Hellenic Journal, xii, (1892 p 221

12 REPORT—1896. a

reasoning by which the whole prehistoric civilisation of the Greek world, so
instinct with naturalism and individuality, is handed over to the least original
member of the Semitic race. The absence in historic Greece of such arts as that
of intarsia in metal work, of glass-making (if true) and of porcelain-making, is
used as a conclusive argument against their practice by an A%gean population, of
uncertain stock, a thousand years earlier, as ifin the intervening dark ages between
the primitive civilisation of the Greek lands and the Classical Renaissance no arts
could have been lost!

Finally, the merchants of Kefté depicted on the Egyptian monuments are once
more claimed as Phoenicians, and with them—though this is by no means a
necessary conclusion, even from the premise—the precious gifts they bear, in-
cluding vases of characteristic Mycenman form and ornament. All this is
pone opposed to the conclusions of the most careful inquirer into the
origins of this mysterious people, Dr. W. Max Miiller (to be distinguished from
the eminent Professor), who shows that the list of countries m which Kefté occurs
places them beyond the limit of Phoenicia or of any Semitic country, and connects
them rather with’ Cilicia and with Cyprus, the scene, as we now know, of important
Mycenvean plantations. It is certain that not only do the Keftiu traders bear
articles of Mycenzean fabric, but their costume, which is wholly un-Semitic, their
leggings and sandals, and the long double locks of hair streaming down below their
armpits, identify them with the men of the frescoes of Mycenz, and of the Vaphio
and Knoésian cups.

The truth is that these Syrian and Pheenician theories are largely to be traced
to the inability to understand the extent to which the primitive inhabitants of the
Mgean shores had been able to assimilate exotic arts without losing their own
individuality. The precocious offspring of our Continent, first come to man’s
estate in the Algean island world, had acquired cosmopolitan tastes, and already
stretched forth his hands to pluck the fruit of knowledge from Oriental boughs.
He had adopted foreign fashions of dress and ornament. His artists revelled in lion-
hunts and palm-trees. His very worship was infected by the creations of foreign
religions.

The great extent to which the Mycenzans had assimilated exotic arts and -
ideas can only be understood when it is realised that this adaptive process had
begun at least a thousand years before, in the earlier period of ®gean culture.
New impulses from Egypt and Chaldzea now succeed the old. The connexion
with Eighteenth and Nineteenth Dynasty Egypt was of so intimate a kind that it
can only be explained by actual settlement from the AJgean side. The abundant
relics of ASgean ceramic manufactures found by Professor Petrie on Eyyptian
sites fully bear out this ict ie The early marks on potsherds discovered
by that explorer seem to carry the connexion back to the earlier Agean period, —
but the painted pottery belongs to what may broadly be described as Mycenean —
times. ‘The earliest relics of this kind found in the rubbish heaps of Kahun,
though it can hardly be admitted that they go quite so far back as the Twelfth
Dynasty date assigned to them by Mr. Petrie (c. 2500 3.c.), yet correspond with the
earliest Mycenzean classes found at Thera and Tiryns, and seem to find their nearest
parallels in pottery of the same character from the cave of Kamares on the northern
steep of the Cretan Ida, recently described by Mr. J. L. Myres and by Dr. Lucio
Mariani, Vases of the more typical Mycenean class have been found by Mr. Petrie
in a series of deposits dated, from the associated Hgyptian relics, from the reign
of Thothmes Til. onwards (1450 3.c.), There is nothing Phoenician about these—
with their seaweeds and marine creatures they are the true products of the
island world of Greece. The counterpart to these Mycenwan imports in Egypt is
seen in the purely Egyptian designs which now invade the northern shores of
the /gean, such as the ceiling of the sepulchral chamber at Orchomenos, or the
wall-paintings of the palace at Tiryns—almost exact copies of the ceilings of the
‘Theban tombs—designs distinguished by the later Egyptian combination of thespiral
and plant ornament which at this period supersedes the pure returning spiral of the
earlier dynasties. The same contemporary evidence of date is seen in the scarabs
and porcelain fragments with the cartouches of Queen 'l'yi and Amenhotep IL,

TRANSACTIONS OF SECTION H. Ss

found inthe Mycenzan deposits. But more than a mere commercial connexion
between the ASgean seat of Mycensean culture and Egypt seems to be indicated by
some of the inlaid daggers from the Acropolis tombs. The subject of that repre-
senting the ichneumons hunting ducks amidst the lotos thickets beside a stream
that can only be the Nile, as much as the intarsia technique, is so purely of
Egypt that it can only have been executed by a Mycenzan artificer resident within
its borders. The whole cycle of Egyptian Nile-pieces thoroughly penetrated
Mycenzean art,—the duck-catcher in his Nile-boat, the water-fowl and butterflies
among the river plauts, the spotted cows and calves, supplied fertile motives for
the Mycenzan goldsmiths and ceramic artists. The griflins of Mycene reproduce
an elegant creation of the New Empire, in which an influence from the Asiatic
side is also traceable.

The assimilation of Babylonian elements was equally extensive. It, too, as we
have seen, had begun in the earlier Agean period, and the religious influence from
the Semitic side, of which traces are already seen in the assimilation of the more
primitive ‘idols ’ to Eastern models, now forms a singular blend with the Egyptian,
as regards, at least, the externals of cult. We see priests, in long folding robes of
Asiatic cut, leading griffins, offering doves, holding axes of a type of Ngyptian
derivation which seems to haye been common to the Syrian coast, the Hittite
regions of Anatolia, and Mycenzan Greece. Female votaries in flounced Baby-
lonian dresses stand before seated Goddesses, rays suggesting those of Shamas
shoot from a Sun-God’s shoulders, conjoined figures of moon and star recall the
symbols of Sin and Istar, and the worship of a divine pair of male and female
divinities is widely traceable, reproducing the relations of a Semitic Bel and Beltis.
The cylinder subjects of Chaldean art continually assert themselves: A Mycenzan
hero steps into the place of Gilgames or Eabani, and renews their struggles with
wild beasts and demons in the same conventional attitudes, of which Christian art
has preserved a reminiscence in its early type of Daniel in the lions’ den. The
peculiar schemes resulting from, ur, at least, brought into continual prominence by
the special conditions of cylinder engraving, with the constant tendency to which
it is able of the two ends of the design to oyerlap, deeply influenced the glyptie
style of Mycene. Here, too, we see the same animals with crossed bodies, with
two bodies and a single head, or simply confronted. These latter affiliations to
Babylonian prototypes have a very important bearing on many later offshoots of
European culture. The tradition of these heraldic groups preserved by the later
Mycenean art, and communicated by it to the so-called ‘ Oriental ’ style of Greece,
finds in another direction its unbroken continuity in ornamental products of the
Hallstatt province, and that of the late Celtic metal workers.

‘But this,’ exclaims a friendly critic, ‘is the old heresy—the “ Mirage
Orientale” overagain. Such heraldic combinations haye originated independently
elsewhere :—why may they not be of indigenous origin in primitive Europe? ’

They certainly may be. Confronted figures occur already in the Dordogne
caves. But, in a variety of instances, the historic and geographical connexion of
these types with the Mycenzean, and those in turn with the Oriental, is clearly
made out. That system which leaves the least call on human efforts at inventive-
ness seems in anthropology to be the safest.

Let us then fully acknowledge the indebtedness of early A2gean culture to the
older civilisations of the East. But this indebtedness must not be allowed to obscure
the fact that what was borrowed was also assimilated. On the easternmost coast
of the Mediterranean, as in Egypt, it is not in a pauper’s guise that the Mycenean
element makes its appearance. It is rather the invasion of a conquering and
superior culture. It has already outstripped its instructors. In Cyprus, which had
lagged behind the A%gean peoples in the race of progress, the Mycenzan relies
make their appearance as imported objects of far superior fabric, side by side with
the rude insular products. The final engrafting on Cypriote soil of what may
be called a colonial plantation of Mycene later reacts on Assyrian art, and
justifies the bold theory of Professor Brunn that the sculptures of Nineveh betray
Greek handiwork. The concordant Hebrew tradition that the Philistines were
immigrants from the Islands of the Sea, the name ‘ Cherethim,’ or Cretans, actually

14 REPORT—1896.

applied to them, and the religious ties which attached ‘Minoan’ Gaza to the cult
of the Cretan Zeus, are so many indications that the 4{gean settlements, which in
all probability existed in the Delta, extended to the neighbouring coast of Canaan,
and that amongst other towns the great staple of the Red Sea trade had passed
into the hands of these prehistoric Vikings. The influence of the Mycenmans on
the later Phoenicians is abundantly illustrated in their eclectic art. The Cretan
evidence tends to show that even the origins of their alphabet receive illustration
from the earlier gean pictography. It is not the Mycenzeans who are Pheeni-
cians. Itis the Phoenicians who, in many respects, acted as the depositaries of
decadent Mycenzean art.

If there is one thing more characteristic than another of Phcenician art, it is its
borrowed nature, and its incongruous collocation of foreignelements. Dr, Helbig
himself admits that if Mycenaean art is to be regarded as the older Pheenician, the
Pheenician historically known to us must have changed his nature. What the
Mycenzeans took they made their own. They borrowed from the designs of Babylon-
ian cylinders, but they adapted them to gems and seals of their own fashion, and
rejected the cylinders themselves. The influence of Oriental religious types is
traceable on their signet rings, but the liveliness of treatment and the dramatic
action introduced into the groups separate them, ‘oto calo, from the conventional
schematism of Babylonian cult-scenes, The older element, the sacred trees and
pillars which appear as the background of these scenes—on this I hope to say
more later on in this Section—there is no reason to regard here as Semitic. It
belongs to a religious stage widely represented on primitive European soil, and
nowhere more persistent than in the West.

Mycenzean culture was permeated by Oriental elements, but never subdued
by them, This independent quality would alone be sufficient to fix its original
birthplace in an area removed from immediate contiguity with that of the
older civilisations of Egypt and Babylonia, The gean island world answers
admirably to the conditions of the case. It is near, yet sufficiently removed,
combining maritime access with insular security. We see the difference if we
compare the civilisation of the Hittites of Anatolia and Northern Syria, in some
respects so closely parallel with that of Mycenz. The native elements were there -
cramped and trammelled from the beginning by the Oriental contact. No real
life and freedom of expression was ever reached ; the art is stiff, conventional,
becoming more and more Asiatic, till finally crushed out by Assyrian conquest.
It is the same with the Phcenicians. But in prehistoric Greece the indigenous
element was able to hold its own, and to recast what it took from others in an
original mould. Throughout its handiwork there breathes the European spirit
of individuality and freedom. Professor Petrie’s discoveries at Tell-el-Amarna
show the contact of this 42gean element for a moment infusing naturalism and life
into the time-honoured conventionalities of Egypt itself.

A variety of evidence, moreover, tends to show that during the Mycenan
period the earlier A2gean stock was reinforced by new race elements coming from
north and west. The appearance of the primitive fiddle-bow-shaped fibula or
safety-pin brings Mycenwan Greece into a suggestive relation with the Danube
Valley and the Terremare of Northern Italy. Certain ceramic forms show the
same affinities; and it may be noted that the peculiar ‘two-storied’ structure of
the ‘ Villanova’ type of urn which characterises the earliest Iron Age deposits of
Italy finds already a close counterpart in a vessel from an Akropolis grave at
Mycense—a parallelism which may point to a common Illyrian source. The

ainted pottery of the Mycenmans itself, with its polychrome designs, betrays
Northern and Western affinities of a very early character, though the glaze and
exquisite technique were doubtless elaborated in the A2gean shores. Examples of
spiraliform painted designs on pottery going back to the borders of the Neolithie
period have been found in Hungary and Bosnia. In the early rock-tombs of Sicily
of the period anterior to that marked by imported products of the fully developed
Mycenwan culture are found unglazed painted wares of considerable brilliancy,
and allied classes recur in the heel of Italy and in the cave deposits of Liguria of
the period transitional between the use of stone and metal. ‘The ‘household gods,

TRANSACTIONS OF SECTION H. 15

if so we may call them, of the Mycenzans also break away from the tradition of
the marble A%gean forms. We recognise the coming to the fore again of primitive
European clay types in a more advanced technique. Here, too, the range of
comparison takes us to the same Northern and Western area. Here, too, in Sicily
and Liguria, we see the primitive art of ceramic painting already applied to these
at the close of the Stone Age. A rude female clay figure found in the Arene
Candide cave near Finalmarina, the upper part of the body of which, armless
and rounded, is painted with brown stripes on a pale rose ground, seems to me to
stand in a closer relation to the prototype of a well-known Mycenean class than
any known example. A small painted image, with punctuated cross-bands over
the breast, from a sepulchral grotto at Villafrati, near Palermo, belongs to the same
early family as the Jucchero types of Butmir, in Bosnia. Unquestionable parallels
to the Mycenzan class have been found in early graves in Servia, of which an
example copied by me some years since in the museum at Belgrade was found near
the site of that later emporium of the Balkan trade, Viminacium, together with
a cup attesting the survival of the primitive A%gean spirals. These extensive
Italian and Illyrian comparisons, which find, perhaps, their converging point in the
North-Western corner of the Balkan peninsula, show, at least approximately, the
direction from which this new European impulse reached the Algean shores.

It is an alluring supposition that this North-Western infusion may connect itself
with the spread of the Greek race in the A%gean islands and the Southern part of
the Balkan peninsula. There seems, at least, to be a reasonable presumption in
favour of this view. The Mycenzan tradition, which underlies so much of the
classical Greek art, is alone sufficient to show that a Greek element was at least
included in the Mycenzan area of culture. Recent criticism has found in the
Mycenean remains the best parallel to much of the early arts and industries
recorded by the Homeric poems. The megaron of the palaces at Tiryns and
Mycenze is the hall of Odysseus; the inlaid metal work of the shield of Achilles
recalls the Egypto-Mycenzean intarsia of the dagger blades; the cup of Nestor with
the feeding doves, the subjects of the ornamental design—the siege-piece, the lion-
hunt, the hound with its quivering quarry—all find their parallels in the works of
the Mycenean goldsmiths. The brilliant researches of Dr. Reichel may be said to
have resulted in the definite identification of the Homeric body-shield with the
most typical Mycenzan form, and have found in the same source the true expla-
nation of the greaves and other arms and accoutrements of the epic heroes.

That a Greek population shared in the civilisation of Mycene cannot reasonably
be denied, but that is far from saying that this was necessarily the only element,
or even the dominant element. Archzeological comparisons, the evidence of geo-
graphical names and consistent tradition, tend to show that a kindred race, repre-
sented later by the Phrygians on the Anatolian side, the race of Pelops and
Tantalos, the special votaries of Kybelé, played a leading part. In Crete a non-
Hellenic element, the Eteocretes, or ‘true Cretans,’ the race of Minds, whose name
is hound up with the earliest sea~empire of the Aigean and perhaps identical with
that of the Minyans of continental Greece, preserved their own language and
nationality to the borders of the classical period. The Labyrinth itself, the double-
headed axe as a symbol of the divinity called Zeus by the Greek settlers, the
common forms in the characters of the indigenous script, local names and historical
traditions, further connect these Mycenan aborigines of Crete with the primitive
population, it, too, of European extraction, in Caria and Pisidia, and with the older
elements in Lycia.

It is difficult to exaggerate the part played in this widely ramifying Mycenwan
culture on later European arts from prehistoric times onwards. Beyond the limits
of its original seats, primitive Greece and its islands, and the colonial plantations
thrown out by it to the west coast of Asia Minor to Cyprus, and in all probability
to Egypt and the Syrian coast, we can trace the direct diffusion of Mycenzean

roducts, notably the ceramic wares, across the Danube to Transylvania and
oldavia. In the early cemeteries of the Caucasus the fibulas and other objects
indicate a late Mycenean source, though they are here blended with allied elements
of a more Danubian character. The Megaeen impress is very strong in Southern

16 REPORT— 1896.

Italy, and, to take a single instance, the prevailing sword-type of that region is of
Mycenwan origin. Along the western Adriatic coast the same influence is traceable
to a very late date in the sepulchral stele of Pesaro and the tympanum relief of
Bologna, and bronze knives of the prehistoric Greek type find their way into the
later Terremare. At Orvieto and elsewhere have even beets discovered Mycenzan
lentoid gems. In Sicily the remarkable excavations of Professor Orsi have brought
to light a whole series of Mycenzean relics in the beehive rock-tombs of the south-
eastern coast, associated with the later class of Sikel fabrics.

Sardinia, whose name has with great probability been connected with the
Shardanas, who, with the Libyan and Adgean races, appear as the early invaders of
Egypt, has already produced a Mycenzan gold ornament. An unregarded fact
points further to the probability that it formed an important outpost of Mycenwan
culture. In 1853 General Lamarmora first printed a MS. account of Sardinian
antiquities, written in the latter years of the fifteenth century by a certain Gilj,
and accompanied by drawings made in 1497 by Johan Virde, of Sassari. Amongst
these latter (which include, it must be said, some gross falsifications) is a capital
and part of a shaft of a Mycenean column in a style approaching that of the
fagade of the ‘Treasury of Atreus.’ It seems to have been found at a place near
the Sardinian Olbia, and Virde has attached to it the almost prophetic description,
‘columna Pelasyica.’ That it is not a fabrication due to some traveller from
Greece is shown by a curious detail. Between the chevrons that adorn it are seen
rows of eight-rayed stars, a detail unknown to the Mycenrean architectural decora-
tion till it occurred on the painted base of the hearth in the megaron of the palace
at Mycenve excavated by the Greek Archeological Society in 1886. In this
neglected record, then, we have an indication of the former existence in Sardinia
of Mycenzean monuments, perhaps of palaces and royal tombs comparable to those
of Mycene itself.

More isolated Mycenwan relics have been found still further afield, in Spain,
and even the Auvergne, where Dr. Montelius has recognised an evidence of an old
trade connexion between the Rhone valley and the Eastern Mediterranean, in the
occurrence of two bronze double axes of AZgean form. It is impossible to do more
than indicate the influence exercised by the Myceniean arts on those of the early.
Iron Age. Here it may be enough to cite the late Mycenzean parallels afforded by
the Agina Treasure to the open-work groups cf bird-holding figures and the
pendant ornaments of a whole series of characteristic ornaments of the Italo-
Hallstatt culture. ;

In this connexion, what may be called a sub-Mycenwan survival in the North-
Western corner of the Balkan peninsula has a special interest for the Celtic West.
Among the relics obtained by the fruitful excavations conducted by the Austrian
archeologists in Bosnia and Herzegovina, and notably in the great prehistoric
cemetery of Glasinatz,a whole series of Early Iron Age types betray distinct
Mycenan affinities. The spiral motive and its degeneration—the concentric
circles grouped together with or without tangential lines of connexion—appears on
bronze torques, on fibula of Mycenwan descent, and the typical finger-rings with
the besil at right angles to the ring. On the plates of other ‘spectacle fibule ’ are
seen triquetral scrolls singularly recalling the gold plates of the Akropolis graves
of Mycenwe. These, as well as other parallel survivals of the spiral system in the
Late Bronze Age of the neighbouring Hungarian region, I have elsewhere ' ventured
to claim as the true source from which the Alpine Celts, together with many Italo-
[llyric elements from the old Venetian province at the head of the Adriatic, drew
the most salient features of their later style, known on the Continent as that of La
Téne. These Mycenzan survivals and Illyrian forms engrafted on the ‘ Hallstatt’
stock were ultimately spread by the conquering Belgic tribes to our own islands, to
remain the root element of the Late Celtic style in Britain—where the older spiral
system had long since died a natural death—and in Ireland to live on to supply the
earliest decorative motives of its Christian art.

' Rhind Lectures, 1895, ‘On the Origins of Celtic Art,’ summaries of which
appeared in the Scotsman.

TRANSACTIONS OF SECTION H. 17

From a Twelfth Dynasty scarab to the book of Durrow or the font of Deerhurst
isa farcry. But, as it was said of old, ‘ Many things may happen in a long time.’
We have not to deal with direct transmission per sa/tum, but with gradual propa-
gation through intervening media. This brief survey of ‘ the Eastern Question in
Anthropology’ will not have been made in vain if it helps to call attention to
the mighty part played by the early ®gean culture as the mediator between
primitive Europe and the older civilisations of Egypt and Babylonia. Adequate
recognition of the Eastern background of the European origins is not the ‘ Oriental
Mirage.’ The independent European element is not affected by its power of assimi-
lation. In the great days of Mycens we see it already as the equal, in many ways
the superior, of its teachers, victoriously reacting on the older countries from which
it had acquired so much. I may perhaps be pardoned if in these remarks, availing
myself of personal investigations, | have laid some stress on the part which Crete
has played in this first emancipation of the European genius. There far earlier
than elsewhere we can trace the vestiges of primeval intercourse with the valley
of the Nile. There more clearly than in any other area we can watch the con-
tinuous development of the germs which gave birth to the higher gean culture.
There before the days of Phcenician contact a system of writing had already been
worked out which the Semite only carried one step further. To Crete the earliest
Greek tradition looks back as the home of divinely inspired legislation and the first
centre of maritime dominion.

Inhabited since the days of the first Greek settlements by the same race,
speaking the same language, and moved by the same independent impulses, Crete
stands forth again to-day as the champion of the European spirit against the
yoke of Asia,

“mr

Brifish Association for the Advancement
of Science.

LIVERPOOL, 1896.

ADDRESS

PHYSIOLOGICAL SECTION

W. H. GASKELL, M.D., LL.D., M.A., F.RS.
PRESIDENT OF THE SECTION,

WHEN I received the honour of an invitation to preside at the Physiological
Section of the British Association, my thoughts naturally turned to the subject of
the Presidential Address, and it seemed to me that the traditions of the British
Association, as well as the fact that a Physiological Section was a comparatively
new thing, both pointed to the choice of a subject of general biological interest
rather than a special physiological topic ; and I was the more encouraged to choose
such a subject because I look upon the growing separation of physiology from
morphology as a serious evil, and detrimental to both scientific subjects. I was
further encouraged to do so by the thought that, after all, a large amount of the
work done in physiological laboratories is anatomical—either minute anatomy or
topographical anatomy, such as the tracing out of the course of nerve-fibre tracts
in the central and peripheral nervous system by physiological methods. Such
methods require to be supplemented by the morphological method of inquiry. If
we can trace up step by step the increasing complexity of the vertebrate central
nervous system ; if we can unravel its complex nature, and determine the original
simpler paths of its conducting fibres, and the original constitution of the special
nerve centres, then it is clear that the method of comparative anatomy would be
of immense assistance to the study of the physiology of the central nervous system
of the higher vertebrates. So also with numbers of other physiological problems,
such as, for instance, the question whether all muscular substances are supplied
with inhibitory as well as motor nerves; to which is closely allied the question of
the nature of the mechanism by which antagonistic muscles work harmoniously
together. Such questions receive their explanation in the researches of Biedermann
on the nerves of the opening and closing muscles of the claw of the crayfish, as
soon as it has been shown that a genetic relationship exists between the nervous
system and muscles of the crayfish and those of the vertebrate.

Take another question of great interest in the present day, viz. the function
of such ductless glands as the thyroid and the pituitary glands. The explanation
of such function must depend upon the original function of these glands, and
cannot, therefore, be satisfactory until it has been shown by the study of compara-
tive anatomy how these glands have arisen. The nature of the leucocytes of the
blood and lymph spaces, the chemical problems involved in the assigning of carti-
lage into its proper group of mucin compounds, and a number of other questions
of physiological chemistry, will all advance a step nearer solution as soon as we
definitely know from what group of invertebrates the vertebrate has arisen.

I have therefore determined to choose as the subject of my address ‘The

I

2 REPORT—1896,

Origin of Vertebrates,’ feeling sure that the evidence which has appealed to me as
a physiologist will be of interest to the Physiological Section; while at the same
time, as I have invited also the Sections of Zoology and Anthropology to be
present, I request that this address may be considered as opening a discussion on
the subject of the origin of vertebrates. I do not desire to speak ex cathedrd,
and to suppress discussion, but, on the contrary, I desire to have the matter
threshed out to its uttermost limit, so that if I am labouring under a delusion the
nature of that delusion may be clearly pointed out to me.

The central pivot on which the whole of my theory turns is the central nervous
system, especially the brain region. There is the ego of each animal; there is the
master-organ, to which all the other parts of the body are subservient. It is to my
mind inconceivable to imagine any upward evolution to be associated with a
degradation of the brain portion of the nervous system. The striking factor of
the ascent within the vertebrate phylum from the lowest fish to man is the steady
increase of the size of the central nervous system, especially of the brain region.
However much other parts may suffer change or degradation, the brain remains
intact, steadily increasing in power and complexity. If we turn to the inverte-
brate kingdom, we find the same necessary law: when the metamorphosis of an
insect takes place, when the larval organs are broken up by a process of histolysis,
and new ones formed, the central nervous system remains essentially intact, and
the brain of the imago differs from that of the larva only in its increased growth
and complexity.

A striking instance of the same necessary law is seen in the case of the
transformation of the larval lamprey, or Ammoceetes, into the adult lamprey, or
Petromyzon; here also, by a process of histolysis, most of the organs of the head
region of the animal undergo dissolution and re-formation, while the brain remains
intact, increasing in size by the addition of new elements, without any sign of
preliminary dissolution, On the other hand, when, as is the case in the Tunicates,
the transformation process is accompanied with a degradation of the central nervous
system, we find the adult animal so hopelessly degraded that it is impossible to
imagine any upward evolution from such a type.

It is to my mind perfectly clear that, in searching among the Invertebrata for-
the immediate ancestor of the Vertebrata, the most important condition which such
ancestor must fulfil is to possess a central nervous system, the anterior part of
which is closely comparable with the brain region of the lowest vertebrate. It is
also clear on every principle of evolution that such hypothetical ancestor must
resemble the lowest vertebrate much more closely than any of the higher vertebrates,
and therefore a complete study of the lowest true vertebrate must give the best
chance of discovering the homologous parts of the vertebrate and the invertebrate.
For this purpose I have chosen for study the Ammoccetes, or larval form of the
lamprey, rather than Amphioxus or the Tunicates, for several reasons. rs

n the first place, all the different organs and parts of the higher vertebrates
can be traced directly into the corresponding parts of Petromyzon, and therefore of
Ammocetes. Thus, every part of the brain and organs of special sense—all the
cranial nerves, the cranial skeleton, the muscular system, &c., of the higher
vertebrates can all be traced directly into the corresponding parts of the lamprey.
So direct a comparison cannot be made in the case of Amphioxus or the
Tunicates. ;

Secondly, Petromyzon, together with its larval form, Ammoceetes, constitutes an
ideal animal for the tracing of the vertebrate ancestry, in that in Ammoccetes we
have the most favourable condition for such investigations, viz. a prolonged larval
stage, followed by a metamorphosis, and the consequent production of the imago or
Petromyzon—a transformation which does not, as in the case of the Tunicates, lead
to a degenerate condition, but, on the contrary, leads to an animal of a distinctly
higher vertebrate type than the Ammoccetes form. As we shall see, the Ammo-
coetes is so full of invertebrate characteristics that we can compare organ for
organ, structure for structure, with the corresponding parts of Limulus and its
allies. Then comes that marvellous transformation scene during herent a
process of histolysis, almost all the invertebrate characteristics are destroyed or

TRANSACTIONS OF SECTION I, 3

changed, and there emerges a higher animal, the Petromyzon, which can now be
compared organ for organ, structure for structure, with the larval form of the
Amphibian ; and so through the medium of these larval forms we can trace upwards
without a break the evolution of the vertebrate from the ancient king-crab form.
On the other hand, Amphioxus and the Tunicates are distinctly degenerate ; it is
easier to look upon either of them as a degenerate Ammoccete than as giving a
clue to the ancestor of the Ammoccete. It is to my mind surprising how difficult
it appears to be to get rid of preconceived opinions, for one still hears, in the
assertion that Petromyzon as well as Amphioxus is degenerate, the echoes of the
ancient myth that the Elasmobranchs are the lowest fishes, and the Cyclostomata
their degenerated descendants.

The characteristic of the vertebrate central neryous system is its tubular
character ; and it is this very fact of its formation as a tube which has led to the
disguising of its segmental character, and to the whole difficulty of connecting
vertebrates with other groups of animals. The explanation of the tubular
character of the central nervous system is the keystone to the whole of my theory
of the origin of vertebrates. The explanation which I have given differs from all
others, in that I consider the nervous system to be composed of two parts—an
internal epithelial tube, surrounded to a greater or less extent by a segmented
nervous system ; and I explain the existence of these two parts by the hypothesis
that the internal epithelial tube was originally the alimentary canal of an
arthropod animal, such as Limulus or Eurypterus, which has become surrounded
to a greater or less extent by the nervous system.

Any hypothesis which deals with the origin of one group of animals from
another must satisfy three conditions :—

1. It must be in accordance with the phylogenetic history of each group. It
must therefore give a consistent explanation of all the organs and tissues of the
higher group which can be clearly shown not to have originated within the group
itself. At the same time, the variations which have occurred on the hypothesis
must be in harmony with the direction of variation in the lower group, if not
actually foreshadowed in that group.

This condition may be called the Phylogenetic test.

2. The anatomical relation of parts must be the same in the two groups, not
only with respect to coincidence of topographical arrangement, but also with
respect to similarity of structure, and, to a large extent, also of function.

This condition may be called the Anatomical test.

3. The peculiarities of the ontogeny or embryological development of the higher
group must receive an adequate explanation by means of the hypothesis, while at
the same time they must help to illustrate the truth of the hypothesis.

This condition may be called the Ontogenetic test.

I hope to convince you that all these three conditions are satisfied by my
hypothesis as far as the head ren of the vertebrate is concerned. I speak only
of the head region at present, because that is the part which I have especially
studied up to the present time, and also because it is natural and convenient to
consider the cranial and spinal nerves separately ; and I hope to demonstrate to you
that not only the nervous system and alimentary canal of such a group of animals
as the Giganostraca—7.e. Limulus and its allied forms—is to be found in the head
region of Ammoceetes, but also, as must logically follow, that every part of the
head region of Ammoccetes has its homologous part in the prosomatic and
mesosomatic regions of Limulus and its allies. I hope to convince you that our
brain is hollow because it has grown round the old cephalic stomach; that our
skeleton arose from the modifications of chitinous ingrowths; that the nerves of
the medulla oblongata—i.e. the facial, glosso-pharyngeal, and vagus neryes—arose
from the mesosomatic nerves to the branchial and opercular appendages of
Limulus, while the nerves of the hind brain are derived from the nerves of the
prosomatic region of Limulus ; that our cerebral hemispheres are but modifications
of the supra-cesophageal ganglia of a scorpion, while our eyes and nose are the
direct descendants of its eyes and olfactory organs.

In the first place, I will give you shortly the reasons why the central nervous

¥2

REPORT—1896,

Fig. 1.—Comparison of Vertebrate Brain from Mammalia to Ammocetes.
(Epithelial parts represented by dotted lines.)

CORP.
STRIAT

MAMMALIA, REPTIULA. AMPHIBIA.

CESOPH opr
CANG

TELEOST, Amocarrs,

TRANSACTIONS OF SECTION I. 5

system of the vertebrate must be considered as derived from the conjoined central
neryous system and alimentary canal of an arthropod.

Comparison of the Central Nervous System of Ammocetes with the
Conjoined Central Nervous System and Alimentary Canal of an
Arthropod Animal such as Limulus.

1. The phylogenetic test proves that the tube of the central nervous system was
originally an epithelial tube, surrounded to a certain extent by nervous material.

The anatomical test then proves that this epithelial tube corresponds in its
topographical relations to the nervous material exactly with the alimentary canal
of an arthropod in its relations to the central nervous system ; and, further, that the
topographical relations, structure, and function of the corresponding parts of this
nervous material are identical in the Ammoceetes and in the iheged.

We see from these diagrams, taken from Edinger, how the greater simplicity of
the brain region as we descend the vertebrate phylum is attained by the reduction

Fig. 2.— Dorsal and lateral view of the Brain of Ammoccetes,

of the nervous material more and more to the ventral side of the central tube, with
the result that the dorsal side becomes more and more epithelial, until at last, as is
seen in Ammoceetes, the roof of the epichordal portion of the brain consists
entirely of fold upon fold of a simple epithelial membrane, interrupted only in one
lace by the crossing of the [Vth nerve and commencement of the cerebellum.
ih the prechordal part of the brain this simple epithelial portion of the tube is
continued on in the middle line as the first choroid plexus of Ahlborn, and the
lamina terminalis round to the ventral side; where, again, in the infundibular
region, the epithelial saccus vasculosus, which has been becoming more and more

6 REPORT—1896. : -

conspicuous in the lower vertebrates, together with the median tube of the
infundibulum, testifies to the withdrawal of the nervous material from this part of
the brain, as well as from the dorsal region. Further, as already mentioned in my
previous papers, the invasion of this epithelial tube by nervous material during the
upward development of the vertebrate is beautifully shown by the commencing
development of the cerebellar hemispheres in the dogfish; by the dorsal growth of
nervous material to form the optic lobes in the Petromyzon ; by the occlusion of
the ventral part of the tube in the epichordal region to form the raphé, as seen in its
commencement in Ammoceetes. Finally, evidence of another kind in favour of
the tubular formation being due to an original non-nervous epithelial tube is given
by the frequent occurrence of cystic tumours, and also by the formation of the
sinus rhomboidalis in birds.

The phylogenetic history of the brain of vertebrates, in fact, is in complete
harmony with the theory that the tubular nervous system of the vertebrate
originally consisted of two parts—viz. an epithelial tube and a nervous system
outside that tube, which has grown over it more and more, and gives not only no
support whatever, but is in direct opposition, to the view that the whole tube was
originally nervous, and that the epithelial portions, such as the choroid plexuses
and roof of the fourth ventricle, are thinned-down portions of that nerve tube.
Passing now to

2. The anatomical test, we see immediately why this epithelial tube comes out
so much more prominently in the lowest vertebrates, for, as can be seen from the
diagrams, and is more fully pointed out in my previous papers,' every part of the
central tube of the vertebrate nervous system corresponds absolutely, both in
position and structure, with the corresponding part of the alimentary canal of the
arthropod, and the nervous material which is arranged round this epithelial tube
is identically the same in topographical position, in structure, and in function as
the corresponding parts of the central nervous system of an arthropod.

Especially noteworthy is it to tind that the pineal eye (PN), with its large
optic ganglion, the ganglion habenule (GHR), falls into its right and appropriate
place as the right median eye of such an animal as Limulus or Eurypterus. In
the following table I will shortly group together the evidence of the anatomical
test.

A. Coincidence of Topographical Position.

LIMULUS AND ITS ALLIES, AMMOC@TES AND VERTEBRATES.
Alimentary Canal :—
1. Cephalic stomach. Ventricles of the brain. ‘
2. Straight intestine,ending in anus. Spinal canal, ending by means of the
neurenteric canal in the anus. a
3. Csophageal tube. Median infundibular tube and saccus
yasculosus.
Nervous System :—
1. Supra-cesophageal ganglia. Brain proper, or cerebral hemispheres.
2. Olfactory ganglia. Olfactory lobe.

3. Optic ganglia of the lateral eyes. | Optic ganglia of the lateral eyes.
4. Optic ganglia of the median eyes. Ganglia habenule.

5. Median eyes. Pineal eyes.

6. Gsophageal commissures. Crura cerebri.

7. Infra-cesophageal or prosomatic Hind brain, giving origin to the IIIrd,
ganglia, giving origin to the IVth, and Vth cranial nerves.

prosomatic nerves.

8. Mesosomatic ganglia, giving origin Medulla oblongata, giving origin to the
to the mesosomatic nerves. Viith, [Xth, and Xth cranial nerves,

9. Metasomatic ganglia. Spinal cord.

' Gaskell, Journ. of Anat. and Physiol. vol. xxiii. 1888; Journ. of Physiol.
vol, x. 1889; Brain, vol. xii. 1889; Q. J. af Mier. Sci. 1890,

si

TRANSACTIONS OF SECTION I,

B. Coincidence of Structure and Physiological Function.

1. The simple non-glandular epithelium of the nerve tube coincides with the
simple non-glandular epithelium of the alimentary canal, ciliated as it is in
Daphnia.’

2. The structure and function of the cerebral hemispheres, olfactory lobes, and
eee oeelis closely resemble the corresponding parts of the supra-cesophageal

nglia.
eo 3. The structure of the right pineal eye, with its nerve end-cells and rhabdites,
is of the same nature as that of a median arthropod eye.

4. The structure of the right ganglion habenule is the same as that of the
optic ganglion of the median eye.

5. The region of the hind brain, like the region of the infra-cesophageal ganglia,
is concerned with the co-ordination of movements.

6. The region of the medulla oblongata, like the mesosomatic region of
Limulus and its allies, is concerned especially with the movements of respiration.

7. The centres for the segmental cranial nerves resemble closely in their
groups of motor cells and plexus substance the centres for the prosomatic and
mesosomatic nerves, with their groups of motor cells and reticulated substance
(Punkt-Substanz).

3. The third test is the ontogenetic test. ‘The theory must be in harmony with,
and be illustrated by, the embryonic development of the central neryous system.
Such is the case, for we see that the nerve tube arises as a simple straight tube
opening by the neurenteric canal into the anus, the anterior part of the tube, z.e.
the cephalic stomach region, being remarkably dilated ; the anterior opening of this
tube, or anterior neuropore, is considered by most authors to have been situated in
the infundibular region.

Next comes the formation of the cerebral vesicles, indicating embryologically
the constricting growth of neryous material outside the cephalic stomach. First,
the formation of two cerebral vesicles by the growth of nervous material in the
position of the ganglia habenuls, posterior commissure, and Meynert’s bundle, z.e.
the constricting intluence of commissures between the optic part of the supra-ceso-
phageal ganglia and the infra-cesophageal ganglia; then the formation of the third
cerebral vesicle by the constricting influence of the 1Vth nerve and commencing
cerebellum. Subsequently the first cerebral vesicle is divided into two parts by
another nerve commissure—the anterior commissure, ¢.e. by nerve material joining
the supra-cesophageal ganglia. Further, the embryological evidence shows that in
the spinal cord region the nerve masses are at first most conspicuous ventrally and
laterally to the original tube, such ventral masses being early connected together
with the strands of the anterior commissure ; ultimately, by the growth of nervous
material dorsalwards, the dorsal portion of the tube is compressed to form the

osterior fissure and the substantia Rolandi, the original large lumen of the old
intestine being thus reduced to the small central canal of the adult nervous system.
Finally, this nerve tube is formed at a remarkably early stage, just as ought to be
the case if it represented an ancient alimentary canal.

The ontogenetic test appears to fail in two points :—

1. That the nerve tube of vertebrates is an epiblastic tube, whereas if it repre-
sented the old invertebrate gut it ought to be largely hypoblastic.

2. The nerve tube of vertebrates is formed from the dorsal surface of the
embryo, while the central nervous system of arthropods is formed from the
ventral surface,

With respect to the first objection, it might be argued, witha good deal of
plausibility, that the term hypoblast is used to denote that surface which is known
by its later development to form the alimentary canal; that in fact, as Heymons’
has pointed out, the theory of the germinal layers is not sufficiently well esta-
blished to give it any phylogenetic value. It is, however, unnecessary to discuss

Hardy and McDougall, Proc. Camb, Philos. Soc. vol. viii. 1893.
Heymons, Die Embryonalentwickl. v. Dermapteren u. Orthapteren, Jena, 1896.

8 REPORT—1896.

this question, seeing that Heymons has shown that the whole alimentary tract in
such arthropods as the earwig, cockroach, and mole cricket, is, like the nerve tube
of vertebrates, formed from epiblast.

The second objection appears to me more apparent than real. The nerve layer
in the vertebrate, as soon as it can be distinguished, is always found to lie ventrally
to the layer of epiblast which forms the central canal. In the middle line of the
body, owing to the absence of the mesoblast layer, the cells which form the noto-
chord and those which form the central nervous system form a mass of cells which
cannot be separated in the earlier stages. The nerve layer in the arthropod lies
between the ventral epiblast and the gut; the nerve layer in the vertebrate lies
between the so-called hypoblast (¢.e. the ventral epiblast of the arthropod) and
the neural canal (¢.c. the old gut of the arthropod). The new ventral surface of
the vertebrate in the head region is not formed until the head fold is completed.
Before this time, when we watch the vertebrate embryo lying on the yolk, with its
nervous system, central canal, and lateral plates of mesoblast, we are watching the
embryonic representation of the pe a Limulus-like animal; then, when the
lateral plates of mesoblast have grown round, and met in the middle line to assist
in forming the new ventral surface, and the head fold is completed, we are watching
the embryonic representation of the transformation of the Limulus-like animal into
the scorpion-like ancestor of the vertebrates.

In the Arthropoda, the simple epithelial tube which forms the stomach and
intestine is not a glandular organ, and we find that the digestive part of the ali-
mentary tract is found in the large organ, the so-called liver. This organ, together
with the generative glands, forms an enormous mass of glandular substance, which,
in Limulus, is tightly packed round the whole of the central neryous system and
alimentary canal, along the whole length of the animal (represented in fig. 4 by
the dark dotted substance). ‘The remains of this glandular mass are seen in
Ammoccetes in the peculiar so-called packing tissue around the brain and spinal
cord (represented in fig. 6 by the dark dotted substance). It satisfies the three
tests to the following extent :—

1. The phylogenetic test.—As we descend the vertebrate phylum, we find that
log pay:

the brain fills up the brain-case to a less and Jess extent, until finally in Ammoceetes-

a considerable space is left between brain and brain-case, filled up with a peculiar
glandular-looking material, interspersed with pigment, which is not fat tissue, and
is most marked in the lowest vertebrates. The natural interpretation of this
phylogenetic history is that the cranial cavity is too large for the brain in the
lowest vertebrates, and is filled up with a peculiar glandular substance because
that glandular substance pre-existed as a functional organ or organs, and not
because it was necessary to surround the brain with packing material in order to

keep it steady, owing to the unfortunate mistake having been made of forming a_

brain much too small for its case.

2. The anatomical test shows that this glandular and pigmented material is in
the same position with respect to the central nervous system of Ammoccetes as the
generative and liver material with respect to the central nervous system and
alimentary canal of Limulus.

8. The ontogenetic test remains to be worked out, 1 do not know the orgin of
this tissue in Ammoccetes ; the evidence has not yet been given by Kuppfer.’ He

has, however, shown that she neural ridge gives origin to a mass of mesoblastic

cells, the further fate of which is not worked out. The whole story is yery sugges-
tive from the point of view of my theory, but incomprehensible on the view that
the neural ridge is altogether nervous.

Finally, we ought to find in the invertebrate group in question indica-
tions of the commencement of the enclosure of the alimentary canal by the
central nervous system; such is, in fact, the case. In the scorpion group a
marked process of cephalisation has gone on, so that the separate ganglia,
both of the prosomatic and mesosomatic region, have fused together, and fused

‘ Kuppfer, Studien +z. vergleich. Entmwicklungsgesch. d. Kopfes der Kranioten,
2, Heft, Miinchen u. Leipzig, 1894.

é

TRANSACTIONS OF SECTION I. 9

also with the large supra-cesophageal mass. In the middle of this large brain
mass a small canal is seen closely surrounded and compressed with nervous
matter, as is shown in this specimen of Thelyphonus ; this canal is the alimentary
canal. Again, Hardy, in his work on the nervous system of Crustacea, has sections
through the brain of Branchipus which demonstrate so close an attachment between
the nervous matter of the optic ganglion and the anterior diverticulum of the gut
that no line of demarcation is visible between the cells of the gut wall and the
cells of the optic ganglion.

For all these reasons I consider that the tubular nature of the vertebrate
central nervous system is explained by my hypothesis much more satisfactorily
and fully than by any other as yet put forward; it further follows that if this
hypothesis enables us to homologise all the other parts of the head region of the
vertebrate with similar parts in the arthropod, then it ceases to be an hypothesis,
but rises to the dignity of the most probable theory of the origin of vertebrates.

Origin of Segmental Cranial Nerves.

1. The phylogenetic test.—It follows from the close resemblance of the brain
region of the central nervous systems in the two groups of animals that the cranial
nerves of the vertebrate must be homologous with the foremost nerves of such an
animal as Limulus, and must therefore supply homologous organs. Leaving out
of consideration for the present the nerves of special sense, it follows that the seg-
mental cranial nerves must be divisible into two groups corresponding to two sets
of segmental muscles, viz. a group supplying structures homologous to the appen-
dages of Limulus and its allies, and a group supplying the somatic or body muscles ;
in other words, we must find precisely what is the most marked characteristic of
the vertebrate cranial nerves, viz. that they are divisible into two sets correspond-
ing to a double segmentation in the head region. The one set, consisting of the
Vth, Vilth, [Xth, and Xth nerves, supply the muscles of the branchial or
visceral segments; the other set, consisting of the IIIrd, [Vth, VIth, and XIIth
nerves, the muscles of the somatic segments. Further, we see that the nerves
supplying the branchial segments, like the nerves supplying the appendages in
Limulus, are mixed motor and sensory, while the nerves supplying the somatic
segments are all purely motor, the corresponding sensory nerves running separately
as the ascending root of the fifth nerve; so also in Limulus, the nerves supplying
the powerful body muscles arise separately from those supplying the appendages,
and also are quite separate from the purely sensory or epimeral (Milne Edwards) !
nerves which supply the surfaces of the carapace in the prosomatic and mesoso-
matic regions. Finally, the researches of Hardy* have shown that the motor portion
of these appendage nerves, just like the nerves of the branchial segmentation in
vertebrates, 7.e, the motor part of the trigeminal, of the facial, of the glosso-pharyngeal,
and of the vagus, arise from nerve centres or nuclei quite separate from those
which give origin to the motor nerves of the somatic muscles. The phylogenetic
history, then, of the cranial nerves points directly to the conclusion that the Vth,
VIith, IXth, and Xth nerves originally innervated structures of the nature of
arthropod appendages.

We can, however, go further than this, for we find, as we trace downwards
throughout the vertebrate kingdom the structures supplied by these nerves, that
they are divisible into two well-marked groups, especially well seen in Ammo-
coetes, viz. :—

1. A posterior group, viz. the VIIth, IXth, and Xth nerves, which arise
from the medulla oblongata and supply all the structures within a branchial
chamber.

2. An anterior group, viz. the Vth nerves, which arise from the hind brain
and supply all the structures within an oral chamber.

! Milne Edwards, ‘ Recherches sur l'Anatomie des Limulus,’ Ann. des Se. Nat.,

5th ser.
* Hardy, Phil. Trans. Roy. Soc. 1894,

13

10

REPORT—1896,

The reason for this grouping is seen when we turn to Limulus and its allies, for
we find that the body is always divided into a prosoma and mesosoma, and that
viz. :—

the appendage nerves are divisible into two corresponding well-marked groups,
1. A posterior or mesosomatic group, which arise from the mesosomatic ganglia
and supply the operculum and branchial appendages.

Fic. 3.—Head Region of Ammoccetes, split longitudinally into a ventral
and dorsal half, (Ventral Half.)

|
oo

Appendages § Nerves

TENTACULAR ~]/

volt = AE

—~
5
il

VELAR [fie

vir

CILIATED
GROOVE
BRANCHI
lst BRANCHIAL CHIAL
Ix

2nd BRANCHIAL

~' OPENINGS
x!

3rd BRANCHIAL—
x?

{
——3
THYROID
ORIFICE
4th BRANCHIAL
x?

5th BRANCHIAL
x‘

6th BRANCHIAL
x?

7th BRANCHIAL
x°

2, An anterior or prosomatic group, which arise from the prosomatic ganglia
and supply the oral or locomotor appendages,

TRANSACTIONS OF SECTION I. 11

Comparison of the Branchial Appendages of Limulus, Eurypterus, &c.,
with the Branchial Appendages of Ammocetes. Meaning of the 1Xth
and Xth Nerves.

We will first consider the posterior group—the VIIth, [Xth, and Xth nerves—
and of these I will take the IXth and Xth nerves together, and discuss the VIIth
separately. These nerves are always described as supplying in the fishes the

Fic. 3.—Head Region of Ammoceetes, split longitudinally into a ventral
and dorsal half. (Dorsal Half.)

Appendages § Nerves

TENTACULAR TRABECULZ

v= i-4
PITUITARY BODY
V BEAR OLD SOPHAGUS

v

SERRATED EDGE
OPERCULAR Tigy CILIATED GROOVE
VII !-? t
Ist BRANCHIAL
IX

2nd BRANCHIAL
x!

3rd BRANCHIAL
x?

4th BRANCHIAL- s

5th BRANCHIAL
x!

6th BRANCHIAL Ni ,
x5
SOMATIC MUSCLE

SPLANCHNIC MUSCLE
7th BRANCHIAL :

x®

QP ee Sh CARTILAGE

(oma)

muscles and other tissues in the walls of a series of gill-pouches, so that the respi-
ratory chamber is considered to consist of a series of pouches, which open on the
one hand into the alimentary canal, and on the other to the exterior. Such a
description is possible even as low down as Petromyzon, but when we pass to the
Ammoceetes we find the arrangement of the branchial chamber has become so
different that it is no longer possible to describe it in terms of gill-pouches. The

14

=
Ly] MUCO-CARTILAGE

12 REPORT—1896,

Fig. 4.—Limulus, Nerves of Appendages and Cartilages.

BRANCHIAL
CARTILAGES

ENTAPOPHYSIAL
CARTILAGINOUS
LIGAMENTS

Fic. 5,—Eurypterus,

TRANSAC'BIONS OF SECTION f. 13

Fig. 6.—Ammoceetes, Nerves of visceral segments and cartilages.

PROSOMA

eH

(pm sh
ro | es Sen

L SITY

5, Cyl
ny

A)
; SSSA ANN
4 =

MESOSOMA

SUBCHORDAL BRANCHIAL
CARTILAGINOUS CARTILAGES
LIGAMENTS

In all three Figures vy, —v,=Prosomatic appendages and nerves ; vii=I1st mesosomatic ap-
pendage or opereular ‘appendage and nerves; ‘ix, x, ... = remaining mesosomatic
appendages and nerves; M = Chilaria in Li imulus, metastoma in Eurypterus,

nature of the branchial chamber is seen in fig. 3, which demonstrates clearly
that the IXth and Xth nerves supply a series of separate gill-bearing struc-
tures or appendages, which hang freely into a common respiratory chamber;
each one of these appendages is moved. by its own separate group of branchial
muscles, and possesses an external branchial bar of cartilage, which, by its
union with its fellows, contributes to form the extra-branchial basket-work so
characteristic of this primitive respiratory chamber, The segmental branchial unit
is clearly in this case, as Rathke originally pointed out, each one of these suspended
gills, or rather gill-bearing appendages; it is absolutely unnatural, as Nestler'
attempts to do, to take a portion of the space between two consecutive gills and
call that a gill-pouch. It is, to my mind, one of the most extraordinary and con-
fusing conceptions of the current morphology to describe an animal in terms of
the spaces between organs, rather than in terms of the organs by which those
spaces are formed. We might as well speak of a net as a number of holes tied
together with string. Another most striking advantage is obtained by considering
the segmental unit to be represented by each of these separate branchial append-
ages—viz, that we can continue the series in the most natural manner (as seen in
fig. 3) in front of the limits of the IXth and Xth nerves, and so find a series
of appendages in the oral chamber serially homologous with the branchial append-
ages. The uppermost of the respiratory appendages is the hyo-branchial, supplied

' Nestler, Archiv f. Naturgeschich. 56, vol. i.

14 REPORT—1896.

by the VIIth nerve, then, passing into the oral chamber, we find a series of non-
branchial appendages, viz. the velar and tentacular appendages, supplied by branches
of the Vth nerve. In fact, by simply considering the tissue between the so-called
gill-pouches as the segmental unit, we no longer get lost in a maze of hypothetical
gill-pouches in front of the branchial region, but find that the resemblances between
the oral and branchial regions, which have led to the endless search for gill-slits
and gill-pouches, really mean that the oral chamber contains appendages just as
the branchial chamber, but that the former were not gill-bearing.

The study of Ammoccetes, then, leads directly to the conclusion that the ancestor
of the vertebrate possessed an oral or prosomatic chamber, which contained a series
of non-branchial, tactile and masticatory appendages, which were innervated from
the fused prosomatic ganglia or hind brain, and a branchial or mesosomatic
chamber, which contained a series of branchial appendages which were innervated
from the fused mesosomatic ganglia or medulla oblongata. These two chambers
did not originally communicate with each other, for the embryological evidence
shows that they are separated at first by the septum of the stomatodseum, and
also that the oral chamber is formed by the forward growth of the lower lip.

The phylogenetic test on the side of Limulus and its congeners agrees in a
remarkable manner with the conclusions derived from the study of Ammoceetes,
for we see that the variation which has occurred in the formation of Eurypterus
from Limulus is exactly of the kind necessary to form the oral and branchial
chambers of the Ammoccetes. Thus, we find with respect to the mesosomatic
appendages that the free, many-jointed appendages of the crustacean become con-
verted into the plate-like appendages of Weenies in which the separate joints are
still visible, but insignificant in comparison with the large branchis-bearing lamella ;
then comes the in-sinking of these appendages, as described by Macleod,’ to form the
branchial lamellg, or so-called lung-books of Thelyphonus, and the branchie of
Eurypterus, in which all semblance of jointed and free appendages disappears and
the branchiz project into a series of chambers or gill-pouches, each pair of which
in Thelyphonus open freely into communication. In this way we see already
the commencement of the formation of a branchial chamber similar to that of
Ammoccetes. ;

So also with the innervation of these mesosomatic appendages, originally a series
of separate mesosomatic ganglia, each of which innervates a separate appendage ;
then a process of cephalisation takes place, in consequence of which, in the first
place, a single ganglion, the opercular ganglion, fuses with the already fused proso-
matic ganglia, as is seen in the stage of Limulus; then, as pointed out by Lankester,
in the different groups of scorpions more and more of the mesosomatic ganglia fuse
together, and so we find the upward variation in this group is distinctly in the
direction of the formation of the medulla oblongata coincidently with the formation |
of a branchial chamber. ;

In a precisely similar way, we find the variation which has occurred in the
prosomatic appendages leads directly to the formation of the oral chamber and oral
appendages of Ammoceetes ; for the original chelate and locomotor appendaa of
Limulus become converted into the tactile non-chelate appendages of terus —
(cf. figs. 4 and 5), and the small chilaria (M) of Limulus, according to Lankester,
fuse in the middle line and. grow forward to form the metastoma of Eurypterus,
thus forming an oral chamber, into which the short tactile appendages could be
withdrawn, closely similar in its formation to the oral shinies of Ammoceetes.
The prosomatic ganglia supplying these oral appendages have already, in Limulus
(see fig. 4), been fused together to form the infra-cesophageal ganglia or hind brain.

The phylogenetic test, then, both on the side of the vertebrate and of the inver-
tebrate, points direct to the conclusion that the peculiarities of the trigeminal and
vagus groups of nerves are due to their origin from nerves supplying prosomatic
and mesosomatic appendages respectively.

2. The anatomical test confirms and emphasises this conclusion in a most
striking manner, for we find not only coincidence of topographical arrangement, a8

' Macleod, Archiv. de Biologie, vol. y. 1884.

TRANSACTIONS OF SECTION I. 15

already mentioned, but also similarity of structure ; thus we see that the blood in
the gill lamella and velar appendages of Ammoccetes does not circulate in distinct
capillaries, but, as in the arthropod appendages, in lacunar spaces, which by the
subdivision of the surface of the appendage to form gill lamella become narrow
channels; that also certain of the branchial muscles and of the muscles of the velar
appendages are of the invertebrate type of so-called tubular muscles. These inver-
tebrate muscles are not found in higher vertebrates, Lut only in Ammocetes, and
moreover disappear entirely at transformation.

Origin of the Vertebrate Cartilaginous Skeleton.

Perhaps, however, the most startling evidence in favour of the homology
between the branchial segments of Ammoccetes and the branchial appendages of
Limulus is found in the fact that a cartilaginous bar external to the branchia
exists in each one of the branchial appendages of Limulus, to which some of the
branchial muscles are attached in precisely the same way as in Ammoceetes. The
branchial cartilages of Limulus (see fig. 4) spring from the entapophyses and form
strong cartilaginous bars which are extra-branchial in position, just as in Ammo-
coetes, in addition to each branchial bar, a cartilaginous ligament passes from one
entapophysis to another, so as to form a longitudinal or entapophysial ligament,
more or less cartilaginous, which extends on each side along the length of the
mesosoma. In precisely the same way the branchial bars of Ammoccetes are
joined together along each side of the notochord by a ligamentous band of more
or less continuous cartilaginous tissue, forming a subchordal or parachordal carti-
laginous ligament.

Further, we see that this cartilage of Limulus is of a very striking structure,
quite different from that of vertebrate cartilage, and that it is formed in a fibro-
massive tissue which, like the matrix of the cartilage, gives a deep purple stain
with thionin, thus showing the presence of some form of chondro-mucoid. This
fibro-massive tissue is closely connected with the chitinogenous cells of the entapo-

hyses.
Saiartiiog is it to find that the branchial cartilages of Ammoccetes possess
identically the same structure as the cartilages of Limulus; that the branchial
cartilages are formed in a fibro-massive tissue which, like the matrix of the cartilage,
ives a deep purple stain with thionin, and that this fibro-massive tissue, to which
hneider ' ives the name of muco-cartilage, or Vorknorpel, entirely disappears at
transformation.

Further, according to Shipley,* the cartilaginous skeleton of the Ammoccetes
when first formed consists simply of a series of straight branchial bars, springing
from a series of cartilaginous pieces arranged bilaterally along the notochord.

The formation cf the trabecule, of the auditory capsules, of the crossbars to
form the branchial basket-work, all occur subsequently, so that exactly those parts
which alone exist in Limulus are those parts which alone exist at an early stage in
Ammoccetes. Another distinction is manifest between these branchial cartilages
and those of the trabecule and auditory capsules, in that the latter do not stain in
the same manner; whereas the matrix of the br»nchial cartilages stains red with
picro-carmine, that of the trabecule and auditory capsules stains deep yellow, so
that the junction between the trabeculee and the first branchial bar is well marked
by the transition from the one to the other kind of staining. The difference cor-
responds to Parker's * soft and hard cartilage.

The new cartilages which are formed at transformation, either in places where
muco-cartilage exists before or by the invasion of the fibrous tissue of the brain-
case by chondroblasts, are all of the hard cartilage variety.

The phylogenetic, anatomical, and ontogenetic history of the formation of the

' Schneider, Beiirage z. Anat. u. Entmwicklungsgesch. der Wirbelthiere. Berlin,
1879.

? Shipley, Quart. Journ. of Micr. Sci. 1887.

® Parker, Phil Trans. Roy. Soo, 1883.

16 REPORT—1896, ae

vertebrate skeleton all show how the bony skeleton is formed from the cartilaginous,
and how the cartilaginous skeleton can be traced back to that found in Petromyzon,
and so to the still simpler form found in Ammocostes ; from this, again, we can pass
directly to the cartilaginous skeleton of Limulus, and so finally trace back the
cranial skeleton of the vertebrate to its commencement in the modified chitinous
ingrowths connected with the entapophyses of Limulus. A similar explanation of
the origin of cartilage from modifications of the chitinous ingrowths of Limulus
was suggested by Gegenbauer! so long ago as 1858, in consideration of the near
chemical resemblances between the chitin and mucin groups of substances.

Comparison of the Thyroid and Hyo-branchial Appendage of Ammocestes
with the Opercular Appendage of LEurypterus, Thelyphonus, de.
Meaning of the VIIth Nerve.

Seeing, then, how easily the [Xth and Xth nerves in Ammoccetes correspond
to the mesosomatic nerves to the branchial appendages in Limulus, and therefore
to the corresponding nerves in such an animal as Eurypterus, we may with con-
fidence proceed to the consideration of the VIIth nerve, and anticipate that it will
be found to innervate a mesosomatic appendage in front of the branchial appendages,
and yet belonging to the branchial group; in other words, if the VIIth nerve is to
fit into the scheme, it ought to innervate a structure or structures corresponding
to the operculum of Limulus or of Thelyphonus, &c. Now we see in figs. 5 and8
the nature of the operculum in Eurypterus and in Thelyphonus, Phrynus, &c. It is
in reality composed of two parts, a median and anterior portion which bears on its
under surface the external genital organs, and a posterior part which bears branchie ;
so that the operculum of these animals may be considered as a genital operculum
fused to a branchial appendage, and therefore double. It is absolutely startling to
find that the branchial segment immediately in front of the glosso-pharyngeal seg-
ment in Ammoceetes (fig. 3) consists of two parts, of which the posterior, the
hyo-branchial, is gill-bearing, while the anterior carries on its under surface the
pseudo-branchial groove of Dohrn, which continues asa ciliated groove up to the _
opening of the thyroid gland.

Again, the comparison of the ventral surfaces of Eurypterus and Ammoccetes-
(cf. fig. 5 and fig. 8) brings to light a complete coincidence of position between
the median tongue of the operculum in the one animal and the median plate of
muco-cartilage in the other animal, which separates in so remarkable a manner the
cartilaginous basket-work of each side, and bears on its under surface the thyroid
gland. Finally, Miss Alcock has shown that not only the hyo-branchial, but also
the thyroid part of this segment, is innervated by the VIIth nerve; so that every
argument which has forced us to the conclusion that the glosso-pharyngeal and ——
yagus nerves are the nerves which originally supplied branchial appendages equally
points to the conclusion that the facial nerve originally supplied the opercular
appendage—an appendage which closed the branchial chamber in front, which con-
sisted of two parts, a branchial and a genital, probably indicating the fusion of
two segments ; and that the thyroid gland belonged to the genital operculum, just as
the branchise belonged to the branchial operculum. This interpretation of the parts
supplied by the facial nerve immediately explains why Dohrn is so anxious to make
a thyroid segment in front of the branchial segments, and why a controversy is still
going on as to whether the facial supplies two segments or one. .

What, then, is the thyroid gland? Of all the organs found in the vertebrate,
with perhaps the single exception of the pineal eye, there is no one which so
clearly is a relic of the invertebrate ancestor as the thyroid gland. This gland,
important as it is known to be in the higher vertebrates, remains of much the
same type of structure down to the fishes, and even to Petromyzon; suddenly,
when we pass to the Ammoccetes, to that larval condition so pregnant with inver-
tebrate surprises, we find that the thyroid has become a large and important organ,

! Gegenbauer, ‘ Anat. Untersuch. eines Limulus,’ Abhand/. der Naturf. Gesellsch.
in Halle, 1858.

—_— Sy

TRANSACTIONS OF SECTION I. 17

totally different in structure from the thyroid of all other vertebrates, though
resembling the endostyl of the Tunicates,

The thyroid of Ammoccetes may be described as a long tube, curled up at its
posterior end, which contains in its wall, along the whole of its length, a peculiar
glandular structure, confined to a small portion of its wall.

A section through this tube is given in fig. 7, and shows how this glandular
structure possesses no alveoli, no ducts, but consists of a column of elongated cells
arranged in a wedge-shaped manner, the apex of the wedge being in the lumen
of the tube; each cell contains a spherical nucleus, situated at the very extreme

Fig. 7.

MUCO-CARTILAGE OPERCULUM
BRANCHIAL ”
Thyroid (Ammoccetes), Thyroid (Scorpion).

end of the cell, farthest away from the lumen of the tube. Such a structure is
different form that of any other vertebrate gland. Its secretion is not in any way
evident. It certainly does not secrete mucus or take part in digestion, and for a
long time I was unable to find any structure which resembled it in the least
degree, apart, of course, from the endostyl of the Tunicates.

Guided, however, by the considerations already put forward, and feeling
therefore convinced that in Eurypterus there must have been a structure re-
sembling the thyroid gland underneath the median projection of the operculum,
I proceeded to investigate the nature of the terminal genital apparatus under-
lying the operculum in the different members of the scorpion family, and reproduce
here (tig. 8) the figures given by Blanchard ' of the appearance of the terminal male
genital organs in Phrynus and Thelyphonus. Emboldened by the striking appear-
ance of these figures, I proceeded to cut sections through the operculum of the
European scorpion, and found that that part of the genital duct which underlies
the operculum, and that part only, contains within its walls a glandular structure
which resembles the thyroid gland of Ammoccetesin a remarkable degree. A section
is represented in fig. 7, and we see that under the operculum in the middle line is
situated a tube, the walls of which in one part on each side are thickened by the
formation of a gland with long cells of the same kind as those of the thyroid; the
nucleus is spherical, and situated at the farther end of the cell, and the cells are
arranged in wedges, so that the extremities of each group of cells come to a point
on the surface of the inner lining of the tube, This point is marked by a small
round opening in the internal chitinous lining of the tube. These cells form a
column along the whole length of the tube, just as in the thyroid gland, so that
the chitinous lining along that column is perforated by numbers of small round

' Blanchard, L’ Organisation du Regne Animas.

REPORT—1896. |

Fig. 8. Comparison of the ventral surface of the branchial region.

THELYPRONUS. EvRYPTERUS

TRANSACTIONS OF SECTION I. 19

AMMOC@TEs.
In all figures the opercular appendage is marked out by its dotted appearance.

holes. This glandular structure is not confined to the male scorpion, but is found
also in the female, though not so well developed.

So characteristic is the structure, so different from anything else, that I have no
hesitation in saying that the thyroid of Ammoccetes is the same structurally as the
thyroid of the scorpion, and that, therefore, in all probability the median projection
of the operculum in the old forms of scorpions, such as Eurypterus, Pterygotus,
Slimonium, &c., covered a glandular tube of the same nature as the thyroid of
Ammocecetes.

We see, then, that the structures innervated by the VIIth, [Xth, and Xth
nerves are absolutely concordant with the view that the primitive vertebrate
respiratory chamber was formed from the mesosomatic eppentines of such a form
as Limulus by a slight modification of the method by which the respiratory
apparatus of Thelyphonus and other Arachnids has been formed, according to
Macleod: The anterior limit of this chamber was formed by the operculum, the
basal part of which formed a septum which originally separated the branchial from
the oral chamber.

Comparison of the Oral Chamber of Ammocaetes with that of Eurypterus.
Meaning of the Vth Nerve.

Passing now to the oral chamber—z.e. to the visceral structures innervated by
the Vth nerve—we find, as already suggested, distinct evidence in Ammoceetes of
the presence of the modified prosomatic appendages of the original Eurypterus-
like form. The large velar appendage is the least modified, possessing as 1t does
the arthropod tubular muscles, a blood system of lacunar blood-spaces, and a
surface covered with a regular scale-like pattern, formed by cuticular nodosities,
similar to that found on the surface of Eurypterus and other scorpions. The
velar appendages show, further, that they are serially homologous with the re-
spiratory appendages, in that they have been utilised to assist in respiration, their
moyements being synchronous with the respiratory movements,

20 REPORT—1896.

The separate part of the Vth nerve which supplies the velar appendage passes
within it from the dorsal to the ventral part of the animal, and then, as Miss
Aleock has shown, turns abruptly forward to supply the large median tentacle,
This extraordinary course leads directly to the conclusion that this median
tentacle, which is in reality double, constitutes, with the velum of each side, the
true velar appendages.

Again, on each side of the middle line there are in Ammoccetes four large
tentacles, each of which possesses a system of muscles, muco-cartilage, and blood-
spaces, precisely similar to the median ventral tentacle already mentioned. Each
of these is supplied, as Miss Alcock has shown, by a separate branch of the
motor part of the Vth nerve (see fig. 6), and each branch is comparable with the
branch supplying the large velar appendage.

That such tentacles are not mere sensory papille surrounding the mouth, but
have a distinet and important morphological meaning, is shown by the fact that
they are transformed in the adult Petromyzon into the remarkable tongue and
suctorial apparatus: a modification of oral appendages into a suctorial apparatus
which is abundantly common among Arthropods.

Finally, the Vth nerve innervates the visceral muscles of the lower and
upper lips of Ammoccetes. In order, then, for the story to be complete, the
homologues of the lower and upper lips must also be found in the system of
prosomatic appendages of forms like Limulus and Eurypterus. The lower lip,
like the opercular or thyroid appendage, possesses a plate of muco-cartilage, and,
as already mentioned, falls into its natural place as the metastoma of the old
Eurypterus-like form, by the enlargement and forward growth of which the oral
chamber of Ammoccetes was formed. The meaning of the upper lip will be con-
sidered with the consideration of the old mouth tube. The comparison of the
metastoma of Eurypterus with the lower lip of Ammoccetes demonstrates the
close resemblance between the oral chambers of Eurypterus and Ammoceetes. In
order to obtain the condition of affairs in Ammoccetes from that in Eurypterus, it
is only necessary that the metastoma should increase in size, and that the last
oral appendage, the large oar-appendage, should follow the example of the other
oral appendages, and be withdrawn into the oral cavity, and so form the velar
appendage.

Thus we see that, just as the mesosomatic appendages of Limulus can be traced
into the branchial and thyroid appendages of Ammoccetes through the inter-
mediate stage of forms similar to Eurypterus, so also the prosomatic appendages
and chilaria of Limulus can be traced into the velar and tentacular appendages
and lower lip of Ammoccetes through the intermediate stage of forms similar to
Eurypterus.

3%. Lastly comes the ontogenetic test. The concordant interpretation of the
origin of the motor part of the Vth, of the VIIth, [Xth, and Xth nerves given by
the anatomical and phylogenetic tests must explain and be illustrated by the facts
of the development of Ammoceetes.

We see :—

1. The oral chamber of Ammoccetes is known in its early stage by the name of
the stomatodw#um, and we find, as might be anticipated, that it is completely
separated at first from the branchial chamber by the septum of the stomatodzeum.

2. This septum is the embryological representative of the basal part of the
operculum, and demonstrates that originally the operculum separated the oral and

__ branchial chambers.

3. Subsequently these two chambers are put into communication by the break-
ing through of this septum, illustrating the communication between the two
chambers by the separation of the median basal parts of the operculum.

4. The velar appendages, the tentacular appendages, the lower lip, all form as
out-buddings, just as the homologous locomotor appendages are formed in arthropods.

5. The branchial bars are not formed by a series of inpouchings in a tube of
uniform thickness, but, as Shipley ' has pointed out, by a series of ingrowths at

' Loe. cit.

——

TRANSACTIONS OF SECTION I. 21

regular intervals ; in other words, the embryological history represents a series of
buddings—z.e. appendages within the branchial chamber similar to the buddings
within the oral chamber—and does not indicate the formation of gill-pouches by
the thinning of an original thick tube at definite intervals.

6. The communication of the branchial chamber with the exterior by the
formation of the gill-slits represents a stage in the ancestral history which is con-
ceivable, but cannot at present be explained with the same certainty as most of the
embryological facts of vertebrate development. I can only say that Striibel! has
pointed out, and I can confirm him, that after the young Thelyphonus has left the
egg, and is on its mother’s back, before the moult which gives it the same form as
the adult, the gills and gill-pouches are fully formed, but do not as yet communi-
cate with the exterior.

7. The branchial cartilages in the Ammoccetes are formed distinctly before the
auditory capsules and trabecul:e, illustrative of the fact that they alone are formed
in Limulus.

Comparison of the Auditory Apparatus of Ammocetes with the Flabellum
of Limulus. Meaning of the VIIIth Nerve.

The correctness of a theory is tested in two ways:—(1) It must explain all
known facts; and (2) it ought to bring to light what is as yet unknown, and the
more it leads to the discovery of new facts, the more certain is it that the theory
is true. So far, we see that the prosomatic and mesosomatie regions of the body in
Limulus and the scorpions are comparable with the corresponding regions of
Ammoceetes as far as their locomotor and branchial appendages are concerned, and
that, therefore, a satisfactory explanation is given of the peculiarities of the Vth,
VIlth, 1Xth, and Xth nerves. In all vertebrates, however, there is invariably
found a special nerve, the VIIIth nerve, entirely confined to the innervation of the
pedal sense-organs of the auditory apparatus. It follows, therefore, that if my
theory is true the VIIIth nerve must be found in such forms as Limulus and its
allies, and that, therefore, a special sense-organ, probably auditory in nature, must
exist between the prosomatic and mesosomatic appendages, at the very base of the
last prosomatic appendage. At present we know nothing about the nature or
locality of the hearing apparatus of Limulus. It is, therefore, all the more in-
teresting to find that in the very position demanded by the theory, at the base of
the last prosomatic appendage, is found a large hemispherical organ, to which a
movable spatula-like process is attached, known by the name of the flabellum.
T1 is organ is confined to the base of this limb; it is undoubtedly a special sense~
organ, being composed mainly of nerves, in connection with an elaborate arrange-
ment of cells and innumerable fine hairs, which are thickly imbedded in the chitin
of the upper surface of the spatula. The arrangement of these cells and hairs is
somewhat similar to that of various sense-organs described by Gaubert,* and
supposed to be auditory. When the animal is at rest this sensory surface projects
upwards and backwards into the crack between the prosomatic and mesosomatic
carapaces, so that while the eyes only permit a look-out forwards and sidewards,
and the whole animal is lying half buried in the sand, any vibrations in the water
around can still pass through this open crevice, and so reach the sensory surface of
this organ.

Finally, the most striking and complete evidence that this sense-organ of
Limulus is homologous with the auditory capsule of Ammoccetes is found in the

fact that in each case the nerve is accompanied into the capsule by a diverticulum

of the liver and generative organs. (See dotted substance in figs. 4 and 6.) In
Limulus the liver and generative organs, which surround the central nervous system
from one end of the body to the other, do not penetrate into any of the appendages,
with the single exception of the flabellum.

In Ammoceetes the peculiar glandular and pigmented tissue which surrounds

' Striibel, Zool. Anzeiger, vol. xv. 1892.
? Gaubert, Ann, d. Sci. Nat., Zool., 7th ser., tome 13, 1892,

22 REPORT—1896.

the brain and spinal cord, and has already been recognised as the remains of the
liver and generative organs, does not penetrate into the velar or other appendages,
but is found only in the auditory capsule, where it enters with and partly surrounds
the auditory nerve.

The coincidence is so startling and unexpected as to bring conviction to my
mind that in the flabel/um of Limulus we are observing the origin of the vertebrate
auditory apparatus ; and it is, to say the least of it, suggestive that in Galeodes the
last locomotor appendage should carry the extraordinary racquet-shaped organs
which Gaubert has shown to be sense-organs of a special character, and that in the
scorpion a large special sense-organ of a corresponding character, viz. the pecten,
should be found which, from its innervation, as given by Patten,’ appears to belong
to the segment immediately anterior to the operculum, rather than to that imme-
diately posterior to it.

Comparison of the Olfactory Organ of Ammoceetes with the Camerostome of
Thelyphonus. Meaning of the Ist Nerve. Also comparison of the
Hypophysis with the Mouth-tube of Thelyphonus.

In precisely the same way as the theory has led to the discovery of a special
sense-organ in Limulus and its allies which may well be auditory, so also it must
lead to the discovery of the olfactory apparatus of the same group, for here also, just
as in the case of the auditory apparatus, we are at present entirely in the dark.

The olfactory organ in such an animal as Thelyphonus ought to be innervated
from the supra-cesophageal ganglia, and ought to be situated in the middle line, in
front of the mouth. ‘lhe mouth is at the anterior end in these animals, the lower
lip or hypostoma (see fig. 9) being formed by the median projecting flanges of the
basal joints of the two pedipalpi; above, in the middle ae is a peculiar median
appendage called the camerostome. Still more dorsal we find in the median line
the rostrum, with the median eyes near its extremity, and laterally on each side of
the camerostome, and dorsal to it, are situated the powerful chelicerse, which are
considered by some authorities to represent antennee. Of these parts the camero-
stome is certainly innervated from the supra-cesophageal ganglia, and upon cutting
sagittal and transverse sections in a very young Thelyphonus we find that the
surface is remarkably covered with very fine sense-hairs, arranged with great regu-
larity and connected with a conspicuous mass of large cells. Upon making trans-
yerse sections through this region we see that the camerostome projects into the
orifice of the mouth, and that its sense-epithelium forms, together with a similar
epithelium on the lower lip, a closed cavity surrounded by a thick hedge of fine
hairs. Here, then, in the camerostome of Thelyphonus 1s a special sense-organ
which, from its position and its innervation, may well be olfactory in function, or at
all events subserve the function of taste.

Upon comparing this organ with the olfactory organ of Ammoccetes we see a
most striking resemblance in general arrangement and structure.

Just as the mouth tube of Thelyphonus is formed of two parts, the pedipalp and
camerostome, so, according to Kuppfer, the nasal tube of Ammoccetes is composed
of two parts, the upper lip and the olfactery protuberance. Of these two parts
we see that the upper lip, or hood, like the pedipalp, is innervated by the Vth nerve,
or nerve of the prosomatic appendages, while the olfactory protuberance, like the
camerostome, is innervated by the Ist nerve. LKuppfer’s investigations show us
further (fig. 9) how the olfactory protuberance is at first free, is directed
yentralwards, and lies at the opening of the hypophysial tube ; how afterwards, by
the forward and upward growth of the upper lip to form the hood, the nasal tube
is formed, with the result that the nasal opening lies on the dorsal surface just in
front of the pineal eye. Kuppfer, like Dohrn and Beard, looks upon this hypo-
physial tube as indicating the palewostoma, or original mouth of the vertebrate, a
view which harmonises absolutely with my theory, and receives the simplest of
explanations from it, for, as you see on the screen, sections through the mouth tube

' Patten, Quart. Journ. of Mier. Sci. vol. xxxi, 1890,

-

TRANSACTIONS OF SECTION I. 23

of Thelyphonus are word for word the same as sections through the nasal tube of
Ammoceetes; here in the one section is the projecting camerostome, here is the
corresponding projection of the olfactory protuberance, here is the sense-epithelium
of the lower lip or hypostoma, here is the sense-epithelium of the upper lip or
hood. Here, as fig. 9 shows, the mouth tube passes in the ventral middle
line to where it turns dorsalwards into the middle of the conjoined nervous mass

Fig. 9.

we “Og

Oral COuamba
ee 7 OT. dp

Jaa P
A.—Median sagittal section through head of young Thelyphonus.
B— , ” ” » * » Ammoceete (after Kuppfer).
C.— full-grown Ammocete (after Kuppfer.)

” ” ” ”

of the supra- and infra-cesophageal ganglia. There the nasal tube ends blindly at
the spot where the infundibular tube lies on the surface of the brain.

Further, the topography of corresponding parts is absolutely the same in the
two animals: in the dorsal middle line the rostrum, with the two median eyes near
its extremity ; in the corresponding position the two pineal eyes ; below this, in the
middle line, the camerostome ; corresponding to it in the Ammoccetes the olfactory

24 REPORT—1896.

protuberance; then the modification of the median projections of the foremost
ventral appendages—the pedipalpi—to form the hypostoma, in the corresponding
position the upper lip or hood of Ammoccetes, which forms the hypostoma as far
as the hypophysial tube or paleostoma is concerned, but an upper lip as far as the
new mouth is concerned. The muscles of this upper lip belong all to the splanch-
nic and not to the somatic group, and are innervated by the appropriate nerve of
the prosomatic appendages, viz. the motor part of the Vth. Ventral to the pedi-
palpi in Thelyphonus there is nothing, ventral to the corresponding lip in the
Ammoceetes is the lower lip, and we have seen that, although such a structure is
absent in the land scorpions of the present day, it was present in the sea scorpions
of old time, was known as the metastoma, and is supposed to be a forward growth
which started at the junction of the prosoma with the mesosoma. Precisely corre-
sponding to this we see from Kuppfer that the lower lip of Ammoccetes is a forward
growth from the junction of the stomatodwum with the respiratory chamber.

We see then, so far, that the comparison of the vertebrate nervous system
with the conjoined central nervous system and alimentary canal of the arthropod
has led to a perfectly consistent explanation of almost all the peculiarities of the
head region of Ammoccetes. We have solved the segmentation of the skull and the
mysteries of the cranial nerves, for we have found that the cranial segmentation of
the vertebrate can be reduced to the segmentation of the prosomatic and mesoso-
matic regions of the Limulus, that the cranial skeleton arose from the modified
internal chitinous skeleton of the Limulus, that the new mouth was formed by the
forward growth of the metastoma, leading to the formation of an oral chamber,
while the old mouth remained as the hypophysial tube, guarded by its olfactory
and taste organs.

Search as we may in the prosomatic and mesosomatic regions of scorpion-like
animals, there are but few points left for elucidation; among these the most
important are, 1, the fate of the coelomic cavities and coxal gland; 2, the fate of
the heart; 3, the fate of the external chitinous covering.

Comparison of the Head Cavities of the Vertebrate with the Prosomatic
and Mesosomatic Celomic Spaces of Limulus.

A recent el by Kishinouye ' on the development of Limulus enables us to
compare the coelomic cavities in the head region of a vertebrate with those of the
prosomatic and mesosomatic segments of Limulus, and we see that the comparison is
wonderfully close ; for whereas each mesosomatic segment possesses a coelomic cavity,
just as each of the segments of the branchial chamber panned by the vagus, glosso-
pharyngeal, and facial nerves possesses a coelomic cavity, this is not the case with the
prosomatic segments. In these latter the first coelomic cavity isa large preoral one,
common to the segment of the first appendage and all the segments in front of it;
the segments belonging to the second, third, and fourth appendages have no coelomic
cavities formed in them, the second ccelomie cavity belongs to the segment of the
fifth appendage. Similarly in the vertebrate in the region corresponding to the
prosoma there are only two head cavities recognised, viz. the lst proral head
cavity of Balfour and V. Wijhe ; and 2nd or mandibular head cavity, associated
especially with the Vth nerve. According to my view the motor part of the Vth
nerve represents the locomotor prosomatie appendages of Limulus, and we see
that already in Limulus the three foremost of these appendages do: not form
coelomic cavities.

In fact, the agreement in the formation and position of the coelomic cavities in
the head region of the vertebrate and in the prosomatic and mesosomatic regions
of Limulus could not well be more exact; further, these cavities agree in this, that
in neither case are they permanent; both in the vertebrate and in the arthropod
they are supplanted by vascular spaces.

' Kishinouye, Journ. of Coll. of Sei, Tokio, vol. v. 1891,

TRANSACTIONS OF SECTION I. 25

Comparison of the Pituitary Gland with the Coxal Gland of Limulus.

In connection with the second ccelomie cavity in Limulus is found an ancient
gland, partially degenerated according to some views, which was probably excretory
in function and has been considered as homologous to the crustacean green glands.
In a precisely corresponding position, and presenting a structure fairly similar to
that of the coxal gland of Limulus, we find in Ammoccetes and in other vertebrates
the pituitary gland, How far this gland tissue is developed in connection with
the mandibular head cavity I do not know, but I venture to suggest that the
complete evidence of its homology with the coxal gland will be found in its
developmental connection with the walls of the 2nd or mandibular head
cavity.

Comparison of the Vertebrate Heart and Ventral Aorta with the Ventral
Longitudinal Branchial Sinuses of Limulus and its Allies.

The heart of the vertebrate presents two striking peculiarities, which make it
different from all invertebrate hearts: first, its developmental history is different;
and, secondly, it is at first essentially a branchial rather than a systemic heart.
The researches of Paul Mayer ' have shown that the subintestinal vein, from which
in the fishes the heart and ventral aorta arise, is in its origin double, so that in all
vertebrates the heart and ventral aorta arise from two long veins which are
originally situated on each side of the middle line. By the formation of the head
fold these come together ventrally, coalesce into a single tube to form the
subintestinal vein and heart, still remaining double as the two ventral aorte
with their branchial branches into each gill, as is well shown in the case of
Ammocestes.

It is a striking coincidence that in Limulus and the Scorpions two large
venous collecting sinuses are found situated in the same ventral position, for the
same purpose of sending blood to the branchis, as already described for the
vertebrate ; still more striking is it to find, according to the researches of Milne
Edwards and Blanchard, that these longitudinal sinuses have already begun to
function as branchial hearts, for they are connected with the pericardium by a system
of transparent muscles, described by Milne Edwards and named by Lankester veno-
pericardiac muscles. These muscles are hollow, both near the vein and near the
pericardium, so that the blood in each case fills the cavity, and, as they contract
with the heart, that part of them in connection with the venous collecting sinus
aad functions, as pointed out by Milne Edwards and Blanchard, as a branchial

eart.

By this theory, then, even the formation of the vertebrate heart is prevised in
Limulus, and I venture to think that in Ammocecetes we see the remnant of the
old dorsal single heart of the arthropod in the form of that peculiar elongated
organ composed of fattily degenerated tissue which lies between the spinal cord
and the dorsal median skin.

Comparison of the Cuticular and Laminated Layers of the Skin of
Ammocetes with Chitinous Layers.

The external epithelial cells of Ammoccetes possess a remarkably thick cuticular
layer. ‘The striated appearance of this layer is due to a number of pores through
which the glandular contents of the cells are poured when the surface is made to
secrete. That this striated appearance is due to true porous canals, just as in
chitin, and not to a series of rods, is easily seen by the inspection of sections, and
also by watching the secretion through them of rose-coloured granules when the
living cell is stained with methylene blue. The surface layer of this cuticular
layer, according to Wolff,’ resists reagents in the same manner as chitin.

' Mayer, Mitth. a. d. Zool. St. zu Neapel, vol. vii.
2 Wolff, Jen. Zeitschr. vol. xxiii,

26 REPORT—1896. = 7

Internal to the epithelial cells of the skin of Ammoccetes is a remarke
layer of tissue, generally called connective tissue. It resembles, however, hist
logically, in the Ammoccetes, a section through chitin most closely; the layer
are perfectly regular and parallel ; cells are found in it with great sparseness, an
it is not until after transformation, when it is altered and invaded by new cell
elements, that it can be looked upon as at all resembling connective tissue. It
resembles chitin in its reaction to hypochlorite of soda. In order to completely —
dissect off this laminated layer from an Ammoccetes, all that is necessary is to
place the animal in a weak solution of hypochlorite of soda, and in a short time it
entirely disappears, bringing to view the muscles, branchial cartilage pigment,
front dorsal part of the central nervous system, &c., in a most striking manner. —
At present I am puzzled that so manifest a chitinous covering should lie internal
to the epithelial cells of the surface; such a position is not, however, unknown
among invertebrates, and may be accounted for in various ways.

For the sake of clearness I will sum up before you in the form of a table the —
corresponding parts in Ammoccetes and in Limulus and its allies, as far as I have
discussed them up to the present, from which you will see that there is not a
single organ which is present in the prosomatic and mesosomatic regions of —
Limulus and its allies which is not found in the corresponding situation and of
corresponding structure in Ammoccetes.

Table of Coincidences between Limulus and its Allies, and between
Ammocetes and Vertebrates. .

LIMULUS AND ITS ALLIES,
Central Nervous System.
Supra-cesophageal ganglia
Optic part. ;
Olfactory part
(Esophageal commissures
Infra-cesophageal ganglia
Prosomatic ganglia
Mesosomatic ganglia
Ventral chain.
Metasomatic ganglia
Alimentary Canal.
Cephalic stomach .
Straight intestine
Terminal part
(Esophagus
Mouth tube
Liver . : : : :
Appendages and Appendage Nerves.
Prosomatic or locomotor append-
ages . ; ; ,

Foremost appendages
Last appendages

Metastoma ; ; :
Nerves of prosomatic appendages .
Mesosomatic or branchial append-

ages. 2 : : :

Opercular appendages

Genital part
Branch. part
Basal part

Branchial appendages

Special Sense Organs and Nerves.
Lateral eyes and optic nerves
Median eyes and nerves

AMMOCCETES AND VERTEBRATES.

Cerebral hemispheres.

Optic thalami, ganglia habenula, &c,
Olfactory lobes.

Crura cerebri.

Epichordal brain.

Hind brain, cerebellum, post-corp. quadrig. —
Medulla oblongata.

Spinal cord.

Ventricular cavities of brain.
Central canal of spinal cord.
Neurenteric canal.
Infundibular tube and saccus vasculosus,
Hypopbysial tube, later nasal canal. _
Part of subarachnoideal glandular tissue.

Appendages of oral chamber or stoma- —
todzum.

Upper lip and tentacles.

Velar appendage and median ventral
tentacle.

Lower lip.

Various branches of Vth nerve.

Appendages of branchial chamber.

Appendage innervated by VIIth nerve.

Thyroid glandand pseudo-branchial groove.

Hyobranchial.

Septum of stomatodreum.

Branchial appendages innervated by IXth
and Xth nerves,

Lateral eyes and optic nerves.
Pineal eyes and nerves,

TRANSACTIONS OF SECTION 1. 07

Camerostoma and olfactory nerves Olfactory organ and Ist nerve.
Flabellum and nerve. 2 . Auditory organ and VIIIth nerve.
Epimeral nerves to surface of pro-
soma and mesosoma . Sensory part of Vth nerve.
Internal and External Skeleton.
Internal skeleton.

Branchial cartilages : . Branchial cartilages.
Entapophysial cartilaginous
ligaments Subchordal cartilaginous ligaments.

Fibro-massive tissue (fore-
runner of cartilage or

‘Vorknorpel’). ; . Muco-cartilage or ‘ Vorknorpel.'
External skeleton.
Chitinous layer. : . Cuticular layer on surface of body and

: subepithelial laminated layer.
KLaeretory Organs and Calomic

Cavities.
Coxal gland . : - : . Pituitary gland.
Ist head cavity, preoral : . lst head cavity, preoral.

2nd head cavity. Cavity of pro-
somatic segments 3

. 2nd head cavity, mandibular.
Cavities to each mesosomatic

segment . ; : : . Cavities of hyoid and branchial segments.
Heart and Vascular System.
Dorsal heart . ; : ! . Column of fatty tissue dorsal to spinal cord,
Longitudinal venous sinuses . Heart and ventral aorta.
Lacunar blood spaces of ap-
pendages é ‘ . Lacunar blood spaces in velar and

branchial appendages.

The Possible Meaning of the Notochord.

Although we can say that every structure and organ in the prosomatic and
mesosomatic regions of Limulus, &c., is to be found in the head region of Ammo-
coetes, we cannot assert the reverse proposition, that every organ in the head region
of Ammocecetes is to be found in Limulus, &c., for we find a notable exception in
the case of the notochord, a structure which is par excellence a vertebrate structure,
and has in consequence given the current name to the group. Such a structure is
clearly not to be found in Limulus and its allies; it has evidently arisen in connec-
tion with the formation of the vertebrate alimentary canal from the oral and
branchial chambers, and it evidently at one time possessed a functional significance,
for the lower we descend in the vertebrate scale the more conspicuous it becomes.

Unfortunately we know nothing of the condition of the notochord in the early
extinct fishes, so that we are reduced to the embryological method of enquiry in our
endeavours to find out the meaning of this organ. This method appears to point
to the origin of the notochord from a tube connected with the alimentary canal,
originally therefore an accessory digestive tube; the reasons why such a view has
been put forward are, first, the origin of the notochord from hypoblast; secondly,
the evidence that it is to a certain extent tubular; and thirdly, that it is an
unsegmented tube extending from the oral to the anal regions of the body.
Beisther argument, to my mind stronger than any other, is based on the principle
that nature repeats herself, and if, therefore, we find the same proliferation of
cells in the same place forming a series of solid notochordal rods, we may fairly
argue that we are observing a series of repetitions of the same process for the same
object. Now the formation of the head region of Petromyzon shows that at first
a median proliferation of hypoblastic cells occurs to form the notochord, which
then separates off from the hypoblast; later on a similar proliferation takes place
to form the subnotochordal rod, which similarly separates off from the hypoblast ;
later still, at the time of transformation, a third median proliferation of the cells of
the hypoblast takes place, to form a solid rod of cells. This solid rod then com-
mences to hollow out at the end nearest the intestine, and the hollowing out

28 REPORT—1896. os

process extends gradually to the oral end, until a hollow tube is formed connectin
the mouth with the intestine. In this way the new gut of the adult Petromyzon
is formed from a solid median rod of cells closely resembling in its formation the
original notochord.

I put it forward therefore as a suggestion, that in the ancient times when the
merostomata were lords of creation and the competition was keen among these —
ancient arthropod forms, in which the neryous system was so arranged that
increase of brain substance tended more and more to compress the food channel,
and therefore to compel to the suction of liquid food instead of the mastication —
of solid, accessory digestive apparatuses were formed, partly in connection —
with the formation of the oral and respiratory chambers, and partly by means of
the formation of the notochord. Of these accessory methods of digestion the
former became permanent, while the latter becoming filled up with the peculiar
notochordal tissue became a supporting structure, still showing by its unsegmented —
character its original function. That a tube formed from the external surface
either as notochord or as the respiratory portion of the alimentary canal in
Ammoccetes should be capable of acting as a digestive tube is clear from the
researches of Miss Alcock,! for she has shown that the secretion of the skin of
Ammoceetes easily digests fibrin in the presence of acid. Such a secretion, like the
similar secretion of the carapace of Daphnia and other crustaceans, was originally
for the purpose of keeping the skin clean.

The evidence which I have put before you is in agreement with the conclusion
that the fore gut of the vertebrate arose gradually from a chamber formed by the
lamellar branchial appendages, which functioned also as a digestive chamber. By
the growth of the lower lip, or metastoma, and the modification of the basal portion
of the last locomotor appendage, which basal part was inside the lower lip, into a
valvular arrangement like the velum, the animal was able to close the opening into
the respiratory chamber and feed as blood-sucker in the way of the rest of its kind,
or, when living food was scarce, keep itself alive by the organic material taken into
its respiratory chamber with the muddy water in which it lived.

The Possible Formation of the Vertebrate Spinal Region.

It remains to briefly indicate the evidence as to the formation of the rest of the _
alimentary canal and the spinal region of the body.

The problems connected with the formation of this region are of a different
nature from those already considered in connection with the cranial region.

In the cranial region the variation that has taken place within the verte-
brate group and in the course of the formation of the vertebrate is, on the
whole, of the nature called by Bateson substantive, ze. increase or suppression —
of parts, while throughout the parts remain constant in their relations to each —
other. It matters not whether it is trog, fish, bird, or mammal we are considering ;
we always find the same cranial nerves supplying the same segments. When we
consider the spinal cord and its immediate junction with the cranial region, this
is no longer so; here we find a repetition of similar segments, with great variation
in the amount of that repetition ; here we find the characteristic feature is meristic
yariation rather than substantive, and so indetermined is the vertebrate in this
respect that even now the same species of animal varies in the number of its
segments and in the arrangement of its nerves. In this part of the vertebrate
body this repetition is seen not only in the central nervous system and its nerves,
but also in the exeretory organs, so that embryology teaches us that the vertebrate
body has grown in length by a series of repetitions of similar segments formed
between the head end and the tail end; such lengthening by repetition of segments —
has been accompanied by the elongation of the unsegmented gut, of the unsegmented
notochord, and of the unsegmented neural canal.

To put it shortly, all the evidence points to and confirms the view so strongly
urged by Gegenbauer, that the head region is the oldest part and the spina

' Alcock, Proce. Camb. Phil. Soc. vol. vii. 1891,

TRANSACTIONS OF SECTION I. 29

region an afterthought, that the attempt so often made to find vertebra and spinal
nerves in the cranial region is an attempt to put the cart in front of the horse—to
obtain youth from old age. We may, it seems to me, fairly argue from the sequence
of events in the embryology of vertebrates that the primitive vertebrate form was
chiefly composed of the head region, and that between the head and the tail was a
short body region. In other words, the respiratory chamber and the cloacal region
were originally close together, just as would be the casein Limulus if the branchial
appendages formed a closed chamber. According, then, to my view, there would
be no difficulty in the respiratory chamber opening originally into the cloacal
region, te. the same cloacal region into which the neurenteric canal already
opened. The short junction tube thus formed would naturally elongate with the
elongation of the body, and, as it originally was part of the respiratory chamber,
it equally naturally is innervated by the vagus nerve. ‘This, then, is the explana-
tion of that most extraordinary fact, viz. that a nerve essentially branchial should
innervate the whole of the intestine except the cloacal region. Whether this is the
true explanation of the formation of the mid-gut of the vertebrate cannot be tested
directly, but certain corollaries ought to follow: we ought to find, on the ground
that the sequence of the phylogenetic history is repeated in the embryo, that,
1, the growth in length of the embryo takes place between the cranial and sacral
regions by the addition of new segments from the cranial end; 2, the formation
of the fore-gut and hind-gut ought to be completed while the mid-gut is still an
undifferentiated mass of yolk cells; 3. the cloacal region ought to be innervated
from the sacral nerves, while the stomach, mid-gut and its appendages, liver and
pancreas, ought to be innervated from the vagus.

The first proposition is a well-known embryological fact. The second pro-
position is also well known for all vertebrates, and is especially well exemplified in
the embryological development of Ammoccetes, according to Shipley. The third
proposition is also well known, and has received valuable enlargement in the recent
researches of Langley and Anderson,'' Further, we see that in this part of the
body the ancestor of the vertebrate must have had a ccelomic cavity the walls of
which were innervated, not from the mesosomatic nerves or respiratory nerves, but
from the metasomatic group of nerves; and in connection with this body cavity
there must have existed a kidney apparatus, also innervated by the metasomatic
nerves ; with the repetition of segments by which the elongation of the animal was
brought about the body cavity was elongated, and the kidney increased by the
repetition of similar excretory organs. All, then, that is required in the original
ancestor in order to obtain the permanent body cavity and urinary organs charac-
teristic of the vertebrate is to postulate the presence of a permanent body cavity m
connection with a single pair of urinary tubes in the metasomatic region of the
body. As yet I have not worked out this part of my theory, and am therefore
strongly disinclined to make any assertions on the subject. I should like, however,
to point out that, according to Kishinouye,? a permanent body cavity does exist in
this part of the body in spiders, known by the name of the stercoral pocket; into
this coelomic cavity the excretory Malphigian tubes open.

The Paleontological Evidence.

It is clear, from what has already been said, that the paleontological evidence
ought to show, first, that the vertebrates appeared when the waters of the ocean
were peopled with the forefathers of the Crustacea and Arachnida, and, secondly,
the earliest fish-like forms ought to be characterised by the presence of a large
cephalic part to which is attached an insignificant body and tail.

Such was manifestly the case, for the earliest fish-like forms appear in
the midst of and succeed to the great era of strange proto-crustacean animals,
when the sea swarmed with Trilobites, Eurypterus, Slimonium, Limulus,
Pterygotus, Ceratioceras, and a number of other semi-crustacean, semi-arachnid

} Langley and Anderson, Journ. of Physiology, vols. xviii., xix.
2 Kishinouye, Journ. of Coll. of Sci. Tokio, yol, iy, 1890, vol. vi. 1894,

80 REPORT—1896,

creatures. When we examine these ancient fishes we find such forms as Pteraspis, —
Pterichthys, Astrolepis, Bothriolepis, Cephalaspis, all characterised by the enormous
disproportion between the extent of the head region and that of the body. Such
forms would have but small power of locomotion, and further evolution consisted
in gaining greater rapidity and freedom of movements by the elongation of the
abdominal and tail regions, with the result that the head region became less and
less prominent, until finally the ordinary fish-like form was evolved, in which the
head and gills represent the original head and branchial chamber, and the flexible
body, with its lateral line nerve and intestine innervated by the vagus nerve,
represents the original small tail-like body of such a form as Pterichthys.

Nay, more, the very form of Pterichthys and the nature of its two large oar-like _
appendages, which, according to Traquair, are hollow, like the legs of insects, sug-
gest a form like Eurypterus, in which the remaining locomotor appendages had
shrunk to tentacles, as in Ammoccetes, while the large oar-like appendages still
remained, coming out between the upper and lower lips and assisting locomotion.
The Ammoccetes-like forms which in all probability existed between the time of
Eurypterus and the time of Pterichthys have not yet been found, owing possibly
to the absence of chitin and of bone in these transition forms, unless we may
count among them the recent find by Traquair of Palzeospondylus Gunni.

The evidence of paleontology, as far as it goes, contirms absolutely the evi-
dence of anatomy, physiology, phylogeny, and embryology, and assists in forming
a perfectly consistent and harmonious account of the origin of vertebrates, the
whole evidence showing how Nature made a great mistake, how excellently she
rectified it, and thereby formed the new and mighty kingdom of the Vertebrata.

ia

Consideration of Rival Theories,

In conclusion I would ask, What are the alternative theories of the origin of
vertebrates? It is a strange and striking fact how often, when a comparative
anatomist studies a particular invertebrate group, he is sure to find the vertebrate
at the end of it: it matters not whether it is the Nemertines, the Capitellide,
Balanoglossus, the Helminths, Annelids, or Echinoderms; the ancestor of the verte-
brate is bound to be in that particular group. Verily I believe the Mollusca alone
have not yet found a champion. On the whole I imagine that two views are
most prominent at the present day—(1) to derive vertebrates from a group of
animals in which the inbatany canal has always been ventral to the nervous
system; and (2) to derive yertebrates from the segmented group of animals,
especially annelids, by the supposition that the dorsal gut of the latter has become
the ventral gut of the former by reversion of surfaces. Upon this latter theory,
whether it is Dohrn or yan Beneden or Patten who attempts to homologise similar
parts, it is highly amusing to see the hopeless confusion into which they one and
all get, and the extraordinary hypotheses put forward to explain the fact that the
gut no longer pierces the brain. One favourite method is to cut off the most
important part of the animal, viz. his supra-cesophageal ganglia, then let the mouth
open at the anterior end of the body, turn the animal over, so that the gut is now
ventral, and let a new brain, with new eyes, new olfactory organs, grow forward
from the infra-cesophageal ganglia. Another ingenious method is to separate the
two supra-cesophageal ganglia, let the mouth tube sling round through the separated
ganglia from ventral to dorsal side, then join up the ganglia and reverse the
animal. The old attempts of Owen and Dohrn to pierce the dorsal part of the
brain with the gut tube either in the region of the pineal eye or of the fourth
ventricle have been given up as hopeless. Still the annelid theory, with its
reversal of surfaces, lingers on, even though the fact of the median pineal eye is
sufficient alone to show its absolute worthlessness.

Then, as to the other view, what a demand does that make upon our credulity!
We are to suppose that a whole series of animals has existed on the earth, the ©
development of which has run parallel with that of the great group of segmented
animals, but throughout the group the nervous system has always been dorsal to —
the alimentary canal. Of this great group no trace remains, either aliye at the —

TRANSACTIONS OF SECTION I. 31

i day or in the record of the rocks, except one or two aberrant, doubtful
‘orms, and the group of Tunicates and Amphioxus, both of which are to be looked
upon as degenerate vertebrates, and indeed are more nearly allied to the Ammo-
ccetes than to any other animal. ‘This hypothetical group does not attempt to
explain any of the peculiarities of the central nervous system of vertebrates; its
advocates, in the words of Lankester, regard the tubular condition of the central
nervous system as in its origin a purely developmental feature, possessing no
pergenatic importance. Strange power of mimicry in nature, that a tube so
‘ormed should mimic in its terminations, in its swellings, in the whole of its topo-
graphical relations to the nervous masses surrounding it the alimentary canal of
the other great group of segmented animals so closely as to enable me to put before
you so large a number of coincidences.

Just imagine to yourselves what we are required to believe! We are to
eres that two groups of animals have diverged from a common stock some-
where in the region of the Coelenterata, that each group has become segmented and
elongated, but that throughout their evolution the one group has possessed a
ventral mouth, with a ventral nervous system and a dorsal gut, while in the
other—the hypothetical group—the mouth and gut have throughout been ventral
and the nervous system dorsal. Then we are further to suppose that, without
being able to trace the steps of the process, the central nervous system in the final
members of this hypothetical group has taken on a tubular form of so striking a
character that every part of this dorsal nerve-tube can be compared to the dorsal
alimentary tube of the other great group of segmented animals. The plain,
straightforward interpretation of the facts is what I have put before you, and
those who oppose this interpretation and hold to the inviolability of the alimentary
canal are, it seems to me, bound to give a satisfactory explanation of the vertebrate
nervous system and pineal eye. The time is coming, and indeed has come, when
the fetish-worship of the hypoblast will give way to the acknowledgment that the
soul of every individual is to be found in the brain, and not in the stomach, and
that the true principle of evolution, without which no upward progress is possible,
consists in the steady upward development of the central nervous system.

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Brifish Associafion for fhe Advancement
of Science.

LIVERPOOL, 1896.

ADDRESS

BOTANICAL SECTION

BY

D, H, SCOTT, M.A., Pua.D., F.R.S., Honorary Keeper of the Jodrell
Laboratory, Royal Gardens, Kew,

PRESIDENT OF THE SECTION.

Present Position of Morphological Botany.

Tue object of modern morphological botany (the branch of our science to which
I propose to limit my remarks) is the accurate comparison of plants, both living
a extinct, with the object of tracing their real relationships with one another,
and thus of ultimately constructing a genealogical tree of the vegetable king-
dom. The problem is thus a purely historical one, and is perfectly distinct
from any of the questions with which physiology has to do.

Yet there is a close relation between these two branches of biology; at any
rate, to those who maintain the Darwinian position. For from that point of view
we see that all the characters which the morphologist has to compare are, or
have been, adaptive. Hence it is impossible for the morphologist to ignore the
functions of those organs of which he is studying the homologies. To those
who accept the origin of species by variation and natural selection there are no
such things as morphological characters pure and simple. There are not two
distinct categories of characters—a morphological and a physiological category—
for all characters alike are physiological. ‘According to that theory, every
organ, every part, colour, and peculiarity of an organism must either be of benefit
to an organism itself, or have been so to its ancestors. . . . Necessarily, according
to the theory of natural selection, structures either are present because they are
selected as useful, or because they are still inherited from ancestors to whom they
were useful, though no longer useful to the existing representatives of those ancestors.”*

The useful characters may have become fixed in comparatively recent times, or
a long way back in the past. In the latter case the character in question may
have become the property of a large group, and thus, as we say, may have become
por ologiealy important

‘or instance, parasitic characters, such as the suppression of chlorophyll, are
equally adaptive in Dodder and in the Fungi. In Dodder, however, such cha-
racters are of recent origin and of little mor hologicny importance, not hinder-
ing us from placing the genus in the natural order Convolvulacee ; while in
Fungi equally adaptive characters haye become the common property of a great
class of plants.

Then, again, the existence of a definite sporophyte generation, which is the
great character of all the higher plants, is in certain Fungi inconstant, even among
members of the same species,

Although there is no essential difference between adaptive and morphological

\ Lankester, Advancement of Science, p. 307,

K

2 REPORT—1896.

characters, there is a great difference in the morphologist’s and the physiologist’s
way of looking at them. The physiologist is interested in the question how
organs work; the morphologist asks, what is their history ?

The morphologist may well feel discouraged at the vastness of the work before
him. The origin of the great groups of plants is perhaps, after all, an insoluble
problem, for the question is not accessible either to observation or experiment.

All that we can directly observe or experiment upon is the occurrence of varia-
tions—perhaps the most important line of research in biology, for it was the study
of variation that led Darwin and Wallace to their grand generalisation. Many
observers are working to-day in the spirit of the great masters, and it is certain
that their work will be fruitful in results. It is evident, however, that such
investigations can at most only throw a side light on the historical question of the
origin of the existing orders and classes of living things. The morphologist has
to attack such questions by other methods of research.

The embryological method has so far scarcely received justice from botanists.

A great deal of what is called embryology in eae is not embryology at all,
but relates to pre-fertilisation changes. Of real embryology—that is to say, the
development of the young plant from the fertilised ovum—there is much less than .
we might expect. Thus no comparative investigation of the embryology of either |
Dicotyledons or Monocotyledons has ever been carried out, our knowledge being
entirely based on a few isolated examples. |

In the cases which have been investigated perhaps excessive attention has been
devoted to the first divisions of the ovum, the importance of which, as Sachs long
ago showed, has been overrated, while the later stages, when the differentiation
of organs and tissues is actually in progress, have been comparatively neglected.

The law of recapitulation (or repetition of phylogeny in ontogeny) has been
very inadequately tested in the vegetable kingdom. Whatever its value may be,
it is certainly desirable that the development of plants as well as animals should
be considered from this point of view ; and this has so far been done in but very
few cases, M. Massart, of Brussels, has made some investigations with this object
on the development of seedlings and of individual leaves. He is led to the con-
clusion that examples of recapitulation are rare among plants. .

So far, at least, embryological research has only yielded certain proof of re- .
capitulation in a few cases, as in the well-known example of the phyllode-bearing
acacias, in which the first leaves of the seedling are normal, while the later formed
ones gradually assume the reduced phyllode form.

A less familiar example is afforded by Gunnera. Here, as is well known, the
mature stem has a structure totally different from that of ordinary Dicotyledons, |
and much resembling that characteristic of most Ferns. In most species of |
Gunnera there are a number of distinct vascular cylinders in the stem, instead of .
one only, and there is never the slightest trace, so far as the adult plant is con-
cerned, of the growth by means of cambium, which is otherwise so general in the
class. The seedling stem, however, is not only monostelic below the cotyledons,
but in this region, though nowhere else, shows distinct secondary growth. Thus,
if we were in any doubt as to the general affinities of Gunnera, owing to its
extraordinary mature structure, we should at once be put on the right track by the
study of the embryonic stem, which alone retains the characteristic dicotyledonous
mode of growth.

It is only in a few cases, however, and for narrow ranges of affinity, that the
doctrine of recapitulation has at present helped in the determination of relationships
among plants. Beyond this, conclusions based on embryology alone tend to
become merely conjectural and subjective. In fact, all comparative work, in so
far as it is limited to plants now living, suffers under the same weakness
that it can never yield certain results, for the question whether given characters
are relatively primitive or recently acquired is one upon which each naturalist is
left to form his own opinion, as the origin of the characters cannot be observed.

! ‘La Récapitulation et I’Innovation en Embryologie Végétale, Bull. de la Soe,
roy. de Bot. de Belgique, vol. xxxiii., 1894,

~

TRANSACTIONS OF SECTION K. 3

To determine the blood-relationships of organisms it is necessary to decipher
their past history, and the best evidence we can have (when we can get it) is from
the ancient organisms themselves. The problem of the morphologist is an
historical one, and contemporary documentary evidence is necessarily the best. It
is paleontology alone which can give us the real historical facts.

ANATOMICAL CHARACTERS,

In judging of the affinities of fossil plants we are often compelled to make
great use of vegetative characters, and more particularly of characters drawn
from anatomical structure. It is true that in many cases we do so because we
cannot help ourselves, such anatomical features being the only characters available
in many of the specimens as at present known. But the value of the method has
been amply proved in other cases where the reproductive structures have also
been discovered, and are found to fully confirm the conclusions based on anatomy.
I need only mention the great groups of the Lepidodendree and the Calamites, in
each of which the anatomical characters, when accurately known, put us at once
on the right track, and lead to results which are only confirmed by the study of
the reproductive organs

Tn this matter fossil botany is likely to react in a beneficial way on the study
of recent plants, calling attention to points of structure which have been passed
over, and showing us the value of characters of a kind to which systematists had
until recently paid but little attention. At present, owing to the work of
Radlkofer, Vesque, and others, anatomical characters are gradually coming into
use in the classification of the higher plants, and in some quarters there may even
be a tendency to over-estimate their importance. Such exaggeration, however, is
only a temporary fault incident to the introduction of a comparatively new
method. In the long run nothing but good can result from the effort to place our
classification on a broader basis. In most cases the employment of additional
characters will doubtless serve only to further confirm the affinities already
detected by the acumen of the older taxonomists. There are plenty of doubtful
points, however, where new light is much needed ; and even where the classifica-
tion is not affected it will be a great scientific gain to know that its divisions are
based on a comparison of the whole structure, and not merely on that of particular
organs.

othe fact that anatomical characters are adaptive is undeniable, but this applies
to all characters, such difference as there is being merely one of degree. Cases
are not wanting where the vegetative tissues show greater constancy than the
organs of reproduction, as, for example, in the Marattiaceew, where there is a
great uniformity in anatomical structure throughout the family, while the
sporangia show the important differences on which the distinction of the genera is
based. It is in fact a mistake to suppose that anatomical characters are neces-
sarily the expression of recent adaptations. On the contrary, it is easy to cite
examples of marked anatomical peculiarities which have become the common
property of large groups of plants.
or instance, to take a case in which I happen to have been specially interested,
the presence of bast to the inside as well as to the outside of the woody zone is a
modification of dicotyledonous structure which is in many groups, at least of
ordinal yalue. The peculiarity is constant throughout the orders Onagracee, Ly-
thracew, Myrtaces, Solanacer, Asclepiadacew, and Apocynaces, not to mention
some less important groups. In other families, such as the Cucurbitace and the
Gentianew, it is nearly constant throughout the order, but subject to some exceptions.
Among the Composite a similar, if not identical, peculiarity appears in some of
the sub-order Cichoriacew, but is here not of more than generic value. In Campa-
nula the systematic importance of internal phloém is even less, for it appears in some
species and not in others. Lastly, there are cases in which a similar character
actually appears as an individual variation, as in Carum Carvi, and, under abnor-
mal conditions, in Phaseolus multiflorus.
These latter cases seem to me worthy of special study, for in them we can

K—2

4 REPORT—1896,

trace, under our very eyes, the first rise of anatomical characters which have else-
where become of high taxonomic importance. A comparative study of the anatomy
of any group of British plants, taking the same species growing under different
conditions, would be sure to yield interesting results if any one had the patience to
undertake it.

Enough has been said to show that a given anatomical character may be of a
high degree of constancy in one group while extremely variable in another, a fact
which is already perfectly familiar as regards the ordinary morphological charac-
ters. For example, nothing is more important in phanerogamic classification than
the arrangement of the floral organs as shown in ground-plan or floral diagram.
Yet Professor Trail’s observations, which he has been good enough to communicate
to me, show that in one and the same species, or even individual, of Polygonum,
almost every conceivable variation of the floral diagram may be found.

There is, in fact, no ‘royal road’ to the estimation of the relative importance
of characters; the same character which is of the greatest value in one group may
be trivial in another; and this holds good equally whether the character be drawn
from the external morphology or from the internal structure.

Our knowledge of the comparative anatomy of plants, from this point of view,
is still very backward, and it is quite possible that the introduction of such charac-
ters into the ordinary work of the Herbarium may be premature ; certainly it must
be conducted with the greatest judgment and caution. We have not yet got our
data, but every encouragement should be given to the collection of such data, so
that our classification in the future may rest on the broad foundation of a com-
parison of the entire structure of plants.

In estimating the relative importance of characters of different kinds we must
not forget that characters are often most constant when most adaptive. Thus, as
Professor Trail informs me, the immense variability of the flowers of Polygonum
goes together with their simple method of self-fertilisation. The exact arrange-
ment is of little importance to the plant, and so variation goes on unchecked. In
flowers with accurate adaptation to fertilisation by insects such variability is not
found, for any change which would disturb the perfection of the mechanism is at
once eliminated by natural selection.

Histoboey.

I propose to say but little on questions of minute histology, a subject which
lies on the borderland between morphology and physiology, and which will be
dealt with next Tuesday far more competently than I could hope to treat it. Last
year my predecessor in the presidency of this Section spoke of a histological dis-
covery (that of the nucleus, by Robert Brown) as ‘the most epoch-making of
events’ in the modern history of botany. The histological questions before us at the
present day may be of no less importance, but we cannot as yet see them in proper

erspective. The centrosomes, those mysterious protoplasmic particles which have
fee supposed to preside over the division of the nucleus, and thus to determine
the plane of segmentation, if really permanent organs of the cell, would have to
rank as co-equal with the nucleus itself. If, on the other hand, as some think,
they are not constant morphological entities, but at most temporary structures
differentiated ad hoc, then we are brought face to face with the question whether
the causes of nuclear division lie in the nucleus itself or in the surrounding
protoplasm. ;

Nothing can be more fascinating than such problems, and nothing more difficult.
We have, at any rate, reason to congratulate ourselves that English botanists are
no longer neglecting the study of the nucleus and its relation to the cell. Fora
long time little was done in these guna? in our country, or at least little was
published, and botanists were generally content to take their information from
abroad, not going beyond a mere verification of other men’s results. Now we
have changed all that, as the communications to this Section sufficiently testify.

Nothing is more remarkable in histology than the detailed agreement in the
structure and behayiour of the nucleus in the higher plants and the higher

q

TRANSACTIONS OF SECTION K. 5

animals, an agreement which is conspicuously manifest in those special divisions
which take place during the maturation of the sexual cells. Is this striking agree-
ment the product of inheritance from common ancestors, or is the parallelism
dependent solely on similar physical conditions in the cells? This is one of the
great questions he which we may hope for new light from the histological dis-
cussion next week.

ALTERNATION OF GENERATIONS.

We have known ever since the great discoveries of Hofmeister that the develop-
ment of a large part of the vegetable kingdom involves a regular alternation of
two distinct generations, the one, which is sexual, being constantly sueceeded—so far
as the normal cycle is concerned—by the other which is asexual. This alternation
is most marked in the mosses and ferns, taking these words in their widest sense,
as used by Professor Campbell in his recent excellent book. In the Bryophyta,
the ordinary moss or liverwort plant is the sexual generation, producing the oyum,
which, when fertilised, gives rise to the moss-fruit, which here alone represents the
asexual stage. The latter forms spores from which the sexual plant is again
developed.

In the Pteridophyta the alternation is equally regular, but the relative develop-
ment of the two generations is totally different, the sexual form being the insigni-
ficant prothallus, while the whole fern-plant, as we ordinarily know it, is the
asexual generation.

The thallus of some of the lower Bryophyta is quite comparable with the pro-
thallus of a fern, so as regards the sexual generation there is no difficulty in seeing
the relation of the two classes; but when we come to the asexual generation or
sporophyte the case is totally different. There is no appreciable resemblance
between the fruit of any of the Bryophyta and the plant of any vascular
Cryptogam.

There is thus a great gap within the Archegoniate ; there is another at the
base of the series, for the regular alternation of the Bryophyta is missing in the
Algee and Fungi, and the question as to what corresponds among these lower
groups to the sporophyte and odphyte of the higher Cryptogams is still disputed.

ow as reyards this life-cycle, which is characteristic of all plants higher than
Alge and Fungi, there are two great questions at present open. The one is
general: are the two generations, the sporophyte and the odphyte, homologous
with one another, or is the sporophyte a new formation intercalated in the life-
history, and not comparable to the sexual plant? The former kind of alternation
has been called homologous, the latter antithetic. This question involves the
origin of alternation; its solution would help us to bridge over the gap between
the Archegoniate and the lower plants. ‘The second problem is more special :
has the sporophyte of the Pteridophyta, which always ek as a complete plant,
been derived from the simple and totally different sporophyte of the Bryophyta, or
are the two of distinct origin ?

At present it is usual, at any rate in England, to assume the antithetic theory
of alternation. Professor Bower, its chief exponent, says:! ‘It will also be
assumed that, whatever may have been the circumstances which led to it, anti-
thetic alternation was brought about by elaboration of the zygote [#.e. the fertilised
ovum] so as to form a new generation (the sporophyte) interpolated between suc-
cessive gametophytes, and that the neutral generation is not in any sense the result
of modification or metamorphosis of the sexual, but a new product having a distinct
phylogenetic history of its own.’ In his essay on ‘ Antithetic as distinguished from
Homologous Alternation of Generations in Plants,’* the author describes the hypo-
thetical first appearance of the sporophyte as follows: ‘Once fertilised, a zygote
might in these plants [the first land plants] divide up into a number of portions
Seda a each of which would then serve as a starting-point of a new indi-
vidual.

' «Spore-produieng Members,’ Phil. Trans. vol. clxxxy. B. (1894) p. 473,
* Annals of Botany, vol. iv. (1890), p. 352. :

6 REPORT—1896.

On this view, the sporophyte first appeared as a mere group of spores formed
by the division of the fertilised ovum. Consequently the inference is drawn that
all the vegetative parts of the sporophyte have arisen by the ‘sterilisation of
potentially sporogenous tissue.’ That is to say, there was nothing but a mass of
spores to start with, so whatever other tissues and organs the sporophyte may form
must be derived from the conversion of spore-forming cells into vegetative cells.
Professor Bower has worked out this view most thoroughly, and as the result he
is not only giving us the most complete account of the development of sporangia
which we have ever had, but he has also done much to clear up our ideas, and to
show us what the course of evolution ought to have been if the assumptions
required by the antithetic theory were justified.

Without entering into any detailed criticism of this important contribution to
morphology, which is still in progress, I wish to point that we are not, after all,
bound to accept the assumption on which the theory rests. There is another view
in the field, for which, in my opinion, much is to be said. The antithetic theory is
receiving a most severe test at the friendly hands of its chief advocate Should it
break down under the strain we need not despair, for another hypothesis remains
which I think quite equally worthy of verification.

This is the theory of Pringsheim, according to which the two generations are
homologous one with another, the odphyte corresponding to a sexual individual
among Thallophytes, the sporophyte to an asexual individual. To quote Prings-
heim’s own words:! ‘The alternation of generations in mosses is immediately
related to those phenomena of the succession of free generations in Thallophytes,
of which the one represents the neutral, the other the sexual plant.’ Further on *
he illustrates this by saying: ‘The moss sporogonium stands in about the same
relation to the moss plant as the sporangium-bearing specimens of Saprolegnia
stand to those which bear odgonia, or as, among the Floridez, the specimens with
tetraspores are related to those with cystocarps.’ This gets rid of the intercalation
of a new generation altogether; we only require the modification of the already
existing sexual and asexual forms of the Thallophytes.

The sudden appearance of something completely new in the life-history, as

required by-the antithetic theory, has, to my mind, a certain improbability. Ev

nihilo nihil fit. We are not accustomed in natural history to see brand-new
structures appearing, like morphological Melcbizedeks, without father or mother.
Nature is conservative, and when a new organ is to be formed it is, as every one
knows, almost always fashioned out of some pre-existing organ. Hence I feel a
certain difficulty in accepting the doctrine of the appearance of an intercalated
sporophyte by a kind of special creation.

We can have no direct knowledge of the origin of the sporophyte in the Bryo-

oe themselves, for the stages, whatever they may have been, are hopelessly lost. _

n some of the Algie, however, we find what most botanists recognise as at least a
parallel development, even if not phylogenetically identical.’ In Gadoyonium, for
example, the odspore does not at once germinate into a new plant, but divides up
into four active zoospores, which swim about and then germinate. In Coleochete
the odspore actually becomes partitioned up by cell-walls into a little mass of
tissue, each cell of which then gives rise to a zoospore.

In both these genera (and many more might be added) the cell-formation in
the germinating odspore has been generally regarded as representing the formation
of a rudimentary sporophyte generation. If we are to apply the antithetic theory
of alternation to these cases, we must assume that the zoospores produced on ger-
mination are a new formation, intercalated at this point of the life-cycle. But is
this assumption borne out by the facts? I think not. In reality nothing new is
intercalated at all, The ‘ zoospores’ formed from the odspore on germination are
identical with the so-called ‘ zoogonidia,’ formed on the ordinary vegetative plant at
all stages of its growth.

In science, as in every subject, we too easily become the slaves of language.

' Gesammelte Abhandlungen, U. p. 370. ® Thid. p. 371.
* See Dower Antithetic Alternation, p. 361.

|

TRANSACTIONS OF SECTION K. 7-

By giving things different names we do not prove that the things themselves are
different. In this case, for example, the multiplication of terms serves, in my
opinion, merely to disguise the facts. The reproductive cells produced by the
ordinary plant of an Gdogonium are identical in development, structure, behaviour,
and germination with those produced by the odspore. The term ‘zoogonidia’ applied
to the former is a ‘question-~begging epithet,’ for it assumes that they are not
homologous with the ‘zoospores’ produced by the latter. I prefer to keep the old
name zoospore for both, as they are identical bodies.

To my mind the point seems to be this. An Cdogonium (to keep to this
example) can form zoospores at any stage of its development ; there is one particu-
lar stage, however, at which they are a/ways formed—namely, on the germination
of the odspore. Nothing new is intercalated, but the irregular and indefinite
succession of sexual and asexual acts of reproduction is here tending to become
regular and definite.

In Spheroplea, as was weil pointed out by the late Mr. Vaizey,! though his
view of alternation was very different from that which I am now putting forward,
the alternation is as definite as in a moss, for here, so far as we know, zoospores
are only formed on the germination of the fertilised ovum. If Spheroplea stood
alone we might believe in the intercalation of these zoospores, as a new stage, but
the comparison with Ulothrix, G8dogonium, Bulbochete and Coleochete shows, I
think, where they came from.

The body formed from the odspore is called by Pringsheim the first neutral
generation. In Gdogonium this has no vegetative development, for the first thing
that the odspore does is to form the asexual zoospores, and it is completely used up
in the process. In other cases it is not in quite such a hurry, and here the first
Peed rckaration has time to show itself as an actual plant. Thisissoin Ulothriz,
a much more primitive form than Cidogonium, for its sexuality is not yet com-
pletely fixed. Hare the zygospore actually germinates, forming a dwarf plant, and
In this stage passes through the dull season, producing zoospores when the weather
becomes more favourable. On Pringsheim’s view the dwarf plant is not a new
creation, but just a rudimentary Udothrix, which soon passes on to spore-formation.
So, too, with the cellular body formed on the germination of the odspore
of Coleochete ; this also is looked upon as a reduced form of thallus. On any
view this genus is especially interesting, for the sporophyte remains enclosed by
the tissue of the sexual generation, thus offering a striking analogy with the
Bryophyta.

In the Phyecomycetous Fungi—plants which have lost their chlorophyll, but
which otherwise in many cases scarcely differ from Algse—the odspore in one and
the same species may either form a normal mycelium, or a rudimentary mycelium
bearing a sporangium, or may itself turn at once into a sporangium (producing
zoospores) without any vegetative development. Here it seems certain that
Pringsheim’s view is the right one, for all stages in the reduction of the first neutral
paeetion lie before our eyes. Nowhere, either here or among the green Algw,

o I see any evidence for the intercalation of a new generation or a new form of
spore on the germination of the fertilised ovum.

Pringsheim extends the same view to the higher plants. The sporogonium
of a mossis for him the highly modified first neutral generation, homologous with
the vegetative plant, but here specially adapted for spore-formation. I have
elsewhere pointed out * that this view has great advantages, for not only does it
harmonise exactly with the actual facts observed in the green Algze and their allies,
but it also helps us to understand the astoundingly different forms which the
archegoniate sporophyte may assume.

It seems to me that Pringsheim was right in regarding the fruit-formation of
Floridez as totally different from the sporophyte-formation of Coleochete or the
Bryophyta. The cystocarp bears none of the marks ofa distinct generation, for
throughout its whole development it remains in the most complete organic connec-

' Annals of Botany, vol. iv., p. 373.
2 Nature, February 21, 1895,

8 REPORT—1896.

tion with the thallus that bears it. The whole Floridean process, often so com-
plicated, appears to be an arrangement for effecting the fertilisation of man
female cells as the result of an original impregnation by a single sperm-cell.
There is here still a great field for future research ; but in the light of our present
knowledge there seems to be no real parallelism with the formation of a sporophyte
in the higher plants.

The gap between the Bryophyta and the Alge remains, unfortunately, a wide
and deep one, and it is not probable that any Alge at present known to us lie at
all near the line of descent of the higher Cryptegams. iceia is often compared
with Coleochete, but it is by no means evident that Riccia is a specially primitive
form. In Anthoceros, which bears some marks of an archaic character, the sporo-
phyte is relatively well developed. To those who do not accept the theory of
intercalation it is not necessary to assume that the most primitive Bryophyta must
have the most rudimentary sporophyte.

Apart from other differences, Bryophyta differ from most green Algz in the
fact that asexual spores are on/y found in the generation succeeding fertilisation.
The spores moreover are themselves quite different from anything in Alge, and
the constancy of their formation in fours among all the higher plants from the
liverworts upwards, is a fact which requires explanation. I should like to sug-
gest to some energetic histologist a comparison of the details of spore-formation
in the lower liverworts and in the various groups of Alge, especially those of the
green series. It is possible that some light might be thus thrown on the origin of
tetrad-spore-formation, a subject as to which Professor Farmer has already gained
some very remarkable results. On Pringsheim’s yiew some indications of homo-
logy between bryophytie and algal spore-formation might be expected, and any-
how the tetrads require some explanation.

The peculiarities of the sporophyte in the Archegoniats, as compared with any
algal structures, depend, no doubt, on the acquirement of a terrestrial habit, while
the odphyte by its mode of fertilisation remains ‘ tied down to a semi-aquatic life.’ '
Professor Bower's phrase ‘ amphibious alternation ’ expresses this view of the case
very happily, and indeed his whole account of the rise of the sporophyte is of the
highest va ue, even though we may not accept his assumption as to its origin’
de novo.

I attach special weight to Professor Bower's treatment of this subject,
because he has shown how the most important of all morphological phenomena
in plants, namely the alternation of generations in Archegoniate, may be explained
as purely adaptive in origin. All Darwinians owe him a debt of gratitude for
this demonstration, which holds good even if we believe the sporophyte to be the
modification of a pre-existing body, and not a new formation.

APOSPORY AND APOGAMY.

We must remember that the theory of homologous alternation has twice
received the strongest confirmation of which a scientific hypothesis is susceptible—
that of verified prediction. In both cases Pringsheim was the happy prophet.
Convinced on structural grounds of the homology of the two generations in
mosses, he undertook his experiments on the moss-fruits, inthe hope,as he says,” that
he would succeed in producing protonema from the subdivided seta of the mosses,
and thus prove the morphological agreement of seta and moss-stem. His experi- —
ment, as everybody knows, was completely succcessful, and resulted in the first
observed cases of apospory, i.e. the direct outgrowth of the sexual from the asexual
generation.

Here he furnished his own verification; in the second case it has come from
other hands. In the paper of 1877, so often referred to, he says (p. 391): ‘ Here,
however [z.e. in the ferns], the act of generation, that is, the formation of sexual
organs and the origin of an embryo, is undoubtedly bound up with the existence
of the spore, until those future ferns are found which I indicated as conceivable in

' Bower, Antithetic Alternation.
2 Ges, Abh, II. p. 407.

TRANSACTIONS OF SECTION K. 9
my preliminary notice, in which the prothallus will sprout forth directly from the
‘ond.’

It is unnecessary to remind English botanists that Pringsheim’s hypothetical
aposporous ferns are now perfectly well known in the flesh ; such cases having
been first observed by Mr. Druery and then fully investigated by Professor
Bower.

A very remarkable case of direct origin of the oéphyte from the sporophyte has
lately been described by Mr. E. J. Lowe, in a variety of Scolopendrium vulgare.
Here the young fern-plant produced prothalli bearing archegonia as direct out-

owths from its second or third frond. The specimen had a remarkable history,
br the young plants were produced from portions of a prothallus which had been
kept alive and repeatedly subdivided during a period of no less than eight years.
I cannot go into the interesting details here, they will be published elsewhere ;
but I wish to call attention to the fact that in this case the production of the sexual
from the asexual generation, occurring so early in life, has no obvious relation to
suppressed spore-formation, and so appears to differ essentially from the cases first
described, which occurred on mature plants. I believe Mr. Lowe’s case is not an
altogether isolated one.

The converse phenomenon—that of apogamy—or the direct origin of an asexual
plant from the prothallus without the intervention of sexual organs, has now been
observed in a considerable number of ferns, the examples already known belonging
to no less than four distinct families: Polypodiacew, Parkeriacese, Osmundacee,
and Hymenophyllacer. In Trichomanes alatum Professor Bower found that
apospory and apogamy co-exist in the same plant, the sporophyte directly giving
rise to a prothallus, which again directly grows out into a sporophyte ; the life-
eycle is thus completed without the aid either of spores or of sexual organs. Dr.
W. H. Lang who has recently made many interesting observations on apogamy,
wiil, I am glad to say, read a paper on the subject before this section, so I need say
no more.

Imust, however, express my own conviction that the facility with which, in ferns,
the one generation may pass over into the other by vegetative growth, and that in
both directions, is a most significant fact. It shows that there is no such hard and
fast distinction between the generations as the antithetic theory would appear to
demand, and in my opinion weighs heavily on the side of the homology of sporo-
pasts and odphyte. I cannot but think that the phenomena deserve greater attention
rom this point of view than they have yet received.

A mode of growth which affords a perfectly eflicient means of abundant propa-
gation cannot, I think, be dismissed as merely teratological.

Since the foregoing paragraph was first written Dr. Lang has made the remark-
able discovery (already communicated to the Royal Society) that in a Lustrea
sporangia of normal structure are produced on the prothallus itself, side by side
with normal archegonia and antheridia. I cannot forbear mentioning this striking
observation, of which we shall hear an account from the discoverer himself.

The strongest advocate of the homology of the prothallus with the fern plant
could scarcely have ventured to anticipate such a discovery.

RELATION BETWEEN Mosszs AND FERNs.

Goebel said,in 1882: ‘The gap between the Bryophyta and the Pteridophyta is
the deepest known to us in the vegetable kingdom. We must seek the starting-
point of the apeyee e: elsewhere than among the Muscinere: among forms which
may have been similar to liverworts, but in which the asexual generations entered
from the first on a different course of development.’' I cannot help feeling that
all the work which has been done since goes to confirm this wise conclusion.
Attempts have been made in the most sportsmanlike manner (to adopt a phrase of
Professor Bower's) to effect a passage over the gulf, but the gulf is still unbridged.
I cannot see anywhere the slightest indication of anything like an intermediate
form between the spore-bearing plant of the Pteridophyta and the spore-bearing

' Schenk’s Handbuch der Botanik, vol. ii. p. 401.
K—3

r 7

10 REPORT—1896,

fruit of the Bryophyta. The plant of the Pteridophyta is sometimes small and
simple, but the smallest and simplest seem just as unlike a bryophytic sporogonium
as the largest and most complex. On the side of the moss group, Anthoceros has.
been often cited as a form showing a certain approach towards the Pteridophytes,
and Professor Campbell in particular has developed this idea with remarkable in-
genuity. An unprejudiced comparison, however, seems to me to show nothing more
here than a very remote parallelism, not suggestive of affinity.

There is no reason to believe that the Bryophyta, as we know them, were the
precursors of the vascular Cryptogams at all. There is a remarkable paucity of
evidence for the geological antiquity of Bryophyta, though mary of the mosses at
any rate would seem likely to have been preserved if they existed. Brongniart
said, in 1849, ‘ The rarity of fossil mosses, and their complete absence up to now
in the ancient strata, are among the most singular facts in geological botany ;’*
and since that time it is wonderful how little has been added. Things seem to
point to both Pteridophyta and Bryophyta having had their origin far back
among some unknown tribes of the Alge. If we accept the homologous theory
of alternation, we may fairly suppose that the sporophyte of the earliest Pterido-
phyta always possessed vegetative organs of some kind. The resemblance between
the young sporophyte and the prothallus in some lycopods indicates that at some
remote period the two generations may not have been very dissimilar. At least
some such idea gives more satisfaction to my mind than the attempt to conceive
of a fern-plant as derived from a sterilised group of potential spores.

The Bryophyta may have had from the first a more reduced sporophyte, the
first neutral generation having, in their ancestors, become more exclusively adapted
to spore-producing functions. I must not omit to mention the idea that the
Bryophyta, or at any rate the true mosses, are degenerate descendants of higher
forms. The presence of typical stomata on the capsule in some cases, and of
somewhat reduced stomata in others, has been urged in support of this view. It
is possible ; but if so, from what have these plants been reduced ?

Few people, perhaps, fully realise how absolutely insoluble such a problem as
we have been discussing really is. I say nothing as to the mosses, which may
have arisen relatively late in geological history. ‘The Pteridophyta, at any rate, -
are known to be of inconceivable antiquity. Not only did they exist in greater
development than at present in the far-off Devonian period, but at that time they
were already accompanied by highly organised gymnospermous flowering-plants.
Probably we are all agreed that Gymnosperms arose somehow from the vascular
Cryptogams. Hence, in the Devonian epoch, there had already been time not only
for the Pteridophyta themselves to attain their full development, but for certain
among them to become modified into complex Phanerogams. It would not be a
rash assumption that the origin of the Pteridophyta took place as long before the
period represented by the plant-bearing Devonian strata as that period is before ~
our own day. Can we hope that a mystery buried so far back in the dumb past
will be revealed ?

It will be understood that I do not wish to assume the réle of partisan for the
homologous theory of alternation. Possibly the whole question lies beyond human
ken, and partisanship would be ridiculous. But I do wish to raise a protest
against anything like a dogmatic statement that alternation of generations must
have been the result of the interpolation of a new stage in the life-history. Let
us, in the presence of the greatest mystery in the morphology of plants, at least
keep an open mind, and not tie ourselves down to assumptions, though we may
use them as working hypotheses.

HisroLoGicaAL CHARACTERS OF THE TWO GENERATIONS.

There is one histological question upon which I must briefly touch because it
bears directly on the subject which we have been considering. I shall say very
little, however, in view of the discussion next Tuesday.

' Tableau des Genres de Végétaux Fossiles, p. 13.

TRANSACTIONS OF SECTION K. Lil

It is now well known that in animals and in the higher plants a remarkable
numerical change takes place in the constituents of the nucleus shortly before the
act of fertilisation, The change consists in the halving of the number of chromo-
somes, those rod-like bodies which form the essential part of the nucleus, and are
regarded by Weismann and most biologists as the bearers of hereditary qualities.
Thus in the lily the number of chromosomes in the nuclei of vegetative cells is
twenty-four ; in the sexual nuclei, those of the male generative cell and of the ovum,
the number is twelve. When the sexual act is accomplished the two nuclei unite,
and so the full number is restored and persists throughout the vegetative life of
the next generation. The absolute figures are of course of no importance; the
point is, the reduction to one half during the maturation of the sexual cells, and
the subsequent restoration of the full number when their union takes place. | say
nothing as to the details or the significance of the process, points which have
been fully dealt with elsewhere, votably in an elaborate recent paper by Miss Fi.
Sargant.

Now, in animals (so far as I am aware) and in angiospermous plants the reduc-
tion of the chromosomes takes place very shortly before the differentiation of the
sexual cells. Thus in a lily the reduction takes place on the male side immediately

rior to the first division of the pollen mother-cell, so that four cell-divisions in all
intervene between the reduction and the final differentiation of the male generative
cells. On the female side the reduction in the same plant takes place in the
primary nucleus of the embryo-sac, so that here there are three divisions between
the reduction and the formation of the ovum. I believe these facts agree very
closely with those observed in the animal kingdom, and so far there is no par-
ticular difficulty, for we can easily understand that if the number of chromosomes
is to be kept constant from one generation to another, then the doubling involved
in sexual fusion must necessarily be balanced by a halving.

There are, however, a certain number of observations on Gymnosperms and
archegoniate Cryptogams which appear to put the matter in a different light.
Overton ' first showed that in a Cycad, Ceratozamia, the nuclei of the prothallus or
endosperm all have the half-number of chromosomes. Here then the reduction
takes place in the embryo sac (or rather its mother-cell), but a great number of
cell-zenerations intervene between the reduction and the maturation of the ovum.
In fact the whole female odphyte shows the reduced number, while the sporophyte
has the full number. The reduction takes place also in the pollen mother-cell.
Further observations have extended this conclusion to some other Gymnosperms.

In Osmunda among the ferns there is evidence to show that reduction takes
place in the spore mother-cell, and that the sexual generation has the half-number
throughout. Professor Farmer has found the same thing in various liverworts,
and shown that the reduction of chromosomes takes place in the spore mother-cell ;
and his observations of cell-diyision in the two generations have afforded some
direct evidence that the odphyte has the half-number and the sporophyte the full
number throughout. Professor Strasburger fully discussed this subject before
Section D at Oxford,*? and came to the conclusion that the difference in number
of chromosomes is a difference between the two generations as such, the sexual
generation being characterised by the half-number, the asexual by the full number.

The importance of this conception for the morphologist is that an actual
histological difference appears to be established between the two generations; @
fact which would appear to militate against their homology. Some botanists even
go so far as to propose making the number of chromosomes the criterion by which
the two generations are to be distinguished. Considering that the whole theory
rests at present on but few observations, I venture to think this both premature
and objectionable ; for nothing can be worse for the true progress of science than
to rush hastily to deductive reasoning from imperfectly established premises.

The facts are certainly very difficult to interpret. Those who accept the
antithetic theory of alternation suppose the sexual generation to be the older, and

' Annals of Botany, vol. vii. p. 139.
* See Annals of Botany, vol. viii. p. 281.

12 REPORT—1896.

that in Thallophytes the plant is always an odphyte, whether ‘actual’ or ‘ potential.’
Hence they believe that in Thallophytes the plant should show throughout
the reduced number of chromosomes, reduction hypothetically taking place
immediately upon the germination of the odspore. If this were true it would lend
some support to the idea of the intercalation of the sporophyte, but at present there
is not the slightest evidence for these assumptions. On the contrary, in the bi
Thallophyte in which chromosome-counting has been successfully accomplished
(Fucus) Professor Farmer and Mr. Williams find exactly the reverse ; the plant
has throughout the fv// number of chromosomes ; reduction first takes place in the
odgonium, immediately before the maturation of the ova, and on sexual fusion the
full number is restored, to persist throughout the vegetative life of the plant.
Fucus is, no doubt, a long way off the direct line of descent of Archegoniate, but
still it is a striking fact that the only direct evidence we have goes dead against
the idea that the sexual generation (and who could call a Fucus-plant anything
else but sexual?) necessarily has the reduced number of chromosomes. This fact
is indeed a rude rebuff to deductive morphology.

I am disposed to regard the different number of chromosomes in the two
generations observed in certain cases among Archegoniate not as a primitive but
as an acquired phenomenon, perhaps correlated with the definiteness of alternation
in the Archegoniatz as contrasted with its indefiniteness in Thallophytes. In
Fucus, in flowering plants, and in animals the soma or vegetative body has the full
number of chromosomes. With these the sporophyte of the Archegoniate agrees;
it is the odphyte which appears to be peculiar in possessing the half-number,
so that if the evidence points to intercalation at all, it would seem to suggest that
the odphyte is the intercalated generation—obviously a reductio ad absurdum.
I do not think we are as yet in a position to draw any morphological conclusions
from these minute histological differences, interesting as they are.

The question how the number of chromosomes is kept right in cases of
apospory and of apogamy is obviously one of great interest, and I am glad to say
that it is receiving attention from competent observers.

SEXUALITY OF FunGI.

Only a few years ago De Bary’s opinion that the fruit of the ascus-bearing
Fungi is normally the result of an act of fertilisation was almost universally
accepted, especially in this country. Although the presence of sexual organs had
only been recorded in comparatively few cases, and the evidence for their functional
activity was even more limited, yet the conviction prevailed that the ascocarp is at
least the homologue of a sexually produced fruit. The organ giving rise to the
ascus or asci was looked upon as homologous with the odgonium of the
Peronospore, the supposed fertilising organ either taking the form of an
antheridial branch as in that group, or, as observed by Stahl in the lichen Collema,
giving rise to distinct male cells, or spermatia. More recently there has been
a complete revolution of opinion on this point, and a year ago or less most
botanists probably agreed that the question of the sexuality of the Ascomycetes
had been settled in a negative sense. This change was due, in the first place, to
the influence of Brefeld, who showed, in a great number of laborious investigations,
that the ascus-fruit may develop without the presence of anything like sexual
organs; while Moller proved that the ily osed male cells of lichens’are in a
multitude of cases nothing but conidia, capable of independent germination.

The view thus gained ground that all the higher Fungi are asexual plants,
fertilisation only occurring in the lower forms, such as the Peronosporee and
Mucorinee, which have not diverged far from the algal stock. The ascus, in
particular, is regarded by this school as homologous with the asexual sporangium of
a Mucor. This theory has been brilliantly expounded ina remarkable book by
Von Tavel, which we cannot but admire as a model of clear morphological
reasoning, whether its conclusions be ultimately adopted or not.

Still, it must be admitted that the Brefeld school were rather apt to ignore

|

TRANSACTIONS OF SECTION K. 13

such pieces of evidence as militated against their views, and consequently their
position was insecure so long as these hostile posts were left uncaptured.

Quite recently the whole question has been reopened by the striking observa-
tions of Mr. Harper, an American botanist working at Bonn.

Zopf, in 1890,' pointed out that up to that time it had not been possible in any
Ascomycete to demonstrate a true process of fertilisation by strictly scientific
evidence, namely, by observing the fusion of the nuclei of the male and female
elements. Exactly the proof demanded has now been afforded by Mr. Harper’s
observations, for in a simple Ascomycete, Spherotheca castagnei, the parasite
causing the hop-mildew, he has demonstrated in a manner which appears to be
conclusive the fusion of the nucleus of the antheridium with that of the ascogo-
nium,” It is impossible to evade the force of this evidence, for the fungus in
question is a perfectly typical Ascomycete, though exceptionally simple, in so far as
only a single ascus is normally produced from the ascogonium. It is unnecessary
to point out how important it is that Mr. Harper’s observations should be con-
firmed and extended to other and more complex members of the order. In the
mean time the few who (unlike your President) had not bowed the knee to Brefeld
may rejoice !

It is impossible to pursue the various questions which press upon one’s mind in
considering the morphology of the Fungi. The occurrence not only of cell-fusion,
but of nuclear fusion, apart from any definite sexual process, now recorded in
several groups of Fungi, urgently demands further inquiry. Such unions of nuclei
have been observed in the basidia of Agarics, the teleutospores of Uredines, and
even in the asci of the Ascomycetes. That such a fusion is not necessarily, as
Dangeard * has supposed, of a sexual nature, seems to be proved by the fact that
it occurs in the young ascus of Spherotheca long after the true act of fertilisation
has been accomplished. It is possible, however, that these phenomena may throw
an important side-light on the significance of the sexual act itself.

Another question which is obviously opened up by the new results is that of
the homologies of the ascus. The observations of Lagerheim * on Dipodascus point
to the sexual origin of a many-spored sporangium not definitely characterised as
an ascus. On the other hand, not only sporangia, but true asci are known to arise
in a multitude of cases direct from the mycelium. It is of course possible that as
regards the asci these are cases of reduction or apogamy ; on the other hand, it is
not wholly impossible that the asci may turn out to be really homologous with a
sexual sporangia, even though their development may often have become associated
with the occurrence of a sexual act However this may be, there is at present no
reason to doubt that a very large proportion of the Fungi are, at least functionally,
sexless plants.

SHALAZOGAMY.

Among the most striking results of recent years bearing on the morphology of
the higher plants, Treub’s discovery of the structure of the ovule and the mode of
fertilisation in Casuarina must undoubtedly be reckoned. The fact that the
pollen-tube in this genus does not enter the micropyle, but travels through the
tissues of the ovary to the chalaza, thus reaching the base of the embryo-sac, was
remarkable enough in itself, and when considered in connection with the presence
of a large sporogenous tissue producing numerous embryo-sacs, appeared to justify
the separation of this order from other angiosperms. Then came the work of Miss
Benson in England, and of Nawaschin in Russia, showing that these remarkable
peculiarities are by no means confined to Casuarina, but extend also in various
modifications to several genera of the Cupuliferee and Ulmacez. They are not,
however, constant throughout these families, so that we are no longer able to
attach to these characters the same fundamental systematic importance which
their first discoverer attributed to them. It is remarkable, however, that these

' «Die Pilze,’ Schenk’s Handbuch der Botanik, Ba. iv. p. 341.

2 Berichte der deutschen bot. Gesellschaft, vol. xiii., January 29, 1896.
5 Le Botaniste, vols. iv. and v.

* Pringsheim's Jahrbuch f. Wiss. Bot. 1892.

14 REPORT—1896,

departures from the ordinary course of angiospermous development oceur in

families some of which have been believed on other grounds to be among the most_

primitive Dicotyledons.

Evippencs OF DrscENT DERIVED FROM Fosstt Borany.

At the beginning of this Address I spoke of the importance of the comparatively
direct evidence afforded by fossil remains as to the past history of plants. It may
be of interest if I endeavour to indicate the directions in which such evidence
seems at present to point.

It was Brongniart who in 1828 first arrived at the great generalisation that
‘nearly all of the plants living at the most ancient geological epochs were
Cryptogams,’' a discovery of unsurpassed importance for the theory of evolution,
though one which is now so familiar that we almost take it for granted. Those
paleozoic plants which are not Cryptogams are Gymnosperms, for the angiospermous
flowering plants only make their appearance high up in the secondary rocks.
Even the Wealden flora, recently so carefully described by Mr. Seward, one of
the secretaries to this section, has as yet yielded no remains referable to Angio-
sperms, though this is about the horizon at which we may expect their earliest
trace to be found.

Attention has already been called to the enormous antiquity of the higher
Cryptogams—the Pteridophyta—and to the striking fact that they are accompanied,
in the earliest strata in which they have been demonstrated with certainty, by
well-characterised Gymnosperms. The Devonian flora, so far as we know it,
though an early, was by no means a primitive one, and the same statement applies
still more strongly to the plants of the succeeding Carboniferous epoch. The
palsozoic Cryptogams, as is now well known, being the dominant plants of their
time, were in many ways far more highly developed than those of our own age;
and this is true of all the three existing stocks of Pteridophyta, Ferns, Lycopods,
and Equisetinez.

We cannot therefore expect any direct evidence as to the origin of these groups
from the paleeozoic remains at present known to us, though it is, of course, quite
possible that the plants in question have sometimes retained certain primitive
characters, while reaching in other respects a high development. For example, the
general type of anatomical structure in the young stems of the Lepidodendrez was
simpler than that of most Aes os at the present day, though in the older trunks
the secondary growth, correlated with arborescent habit, produced a high degree of
complexity. On the whole, however, the interest of the paleozoic Cryptogams
does not consist in the revelation of their primitive ancestral forms, but rather in
their enabling us to trace certain lines of evolution further upward than in recent
plants. From the Carboniferous rocks we first learn what Cryptogams are capable
of. In descending to the early strata we do not necessarily trace the trunk of the
genealogical tree to its base; on the contrary, we often light on the ultimate twigs
of extensive branches which died out long before our own period.

In a lecture which I had the honour of giving last May before the Liverpool
Biological Society, I pointed out how futile the search for ‘ missing links’ among
fossil plants is likely to be. The lines of descent must have been so infinitely
oe in their ramification that the chances are almost hopelessly great against
our happening upon the direct ancestors of living forms. Among the collateral
lines, however, we may find invaluable indications of the course ot descent.

Fossil botany has revealed to us the existence in the Carboniferous epoch of a
fourth phylum of vascular Cryptogams quite distinct from the three which have
come down—more or less reduced—to our own day. This is the group of
Sphenophyllex, plants with slender ribbed stems, superposed whorls of more or less
wedge-shaped leaves, and very complex strobili with stalked sporangia. The
group to a certain extent combines the characters of Lycopods and Horsetails,
resembling the former in the primary anatomy, and the latter, though remotely, in
external habit and fructification, Like so many of the early Cryptogams, Spheno-

' Williamson, Reminiscences of a Yorkshire Naturalist, 1896, p. 198,

TRANSACTIONS OF SECTION K. 15

phyllum possessed well-marked cambial growth. One may hazard the guess that
this interesting group may have been derived from some unknown form lying at
the root of both Calamites and Lycopods. The existence of the Sphenophyle
certainly suggests the probability of a common origin for these two series.

In few respects is the progress made recently in fossil botany more marked
than in our knowledye of the affinities of the Calamariew. [ven so recently as
the publication of Vount Solms-Laubach’s unrivalled introduction to ‘ Fossil
Botany,’ the relation of this family to the Horsetails was still so doubtful that the
author dealt with the two groups in quite different parts of his book. This is
never likely to happen again. The study of vegetative anatomy and morphology
on the one hand, and of the perfectly preserved fructifications on the other, can
leave no doubt that the fossil Calamariez and the recent Hquiseta belong to one
and the same great family, of which the palozoic representatives are, generally
speaking, by far the more highly organised. ‘This is not only true of their
anatomy, which is characterised by secondary growth in thickness just like that of
a Gymnosperm, but also applies to the reproductive organs, some of which are
distinctly heterosporous. In the genus Calamostachys we are, I think, able to trace
the first rise of this phenomenon.

The external morphology of the cones is also more varied and usually more
complex than that of recent Equiseta, though in some Carboniferous forms, as
in the so-called Calamostachys tenuissima of Grand’ Eury, we find an exactly
Equisetum-like arrangement.

The position of the Sigillarie as true members of the Lycopod group is now
well established. The work of Williamson proved that there is no fundamental
distinction between the vegetative structure of Lepidodendron, which has always
been recognised as lycopodiaceous, and that of Sigil/aria. Secondary growth in
thickness, the character which here, as in the case of the Calamodendrew, misled
Brongniart, is the common property of both genera. Then came Zeiller’s dis-
covery of the cones of Sigillaria, settling beyond a doubt that they are hetero-
ere Cryptogams. A great deal still remains to be done, more especially as to
the relation of Stigmaria to the various types of lyeopodiaceous stem. At present
we are perhaps too facile in accepting Stigmaria ficoides as representing the
underground organs of almost any carboniferous Lycopod.

We are now in possession of a magnificent mass of data for the morphology
of the palsozoic lycopods, and have perhaps hardly yet realised the richness of
our material. I refer more especially to specimens with structure, on which, here
as elsewhere, the scientific knowledge of fossil plants primarily depends,

It is scarcely necessary to repeat what has been said so often elsewhere, that
the now almost universal recognition of the cryptogamic nature of Calamodendres
and Sigillarie is a splendid triumph for the opinions of the late Professor
Williamson, which he gallantly maintained through a quarter of a century of
controversy.

Perhaps, however, the keenest interest now centres in the Ferns and fern-like
plants of the carboniferous epoch, No fossil remains of plants are more abundant,
or more familiar to collectors, than the beautiful and varied fern-fronds from the
older strata. The mere form, and even the venation of these fronds, however,
really tell us little, for we know how deceptive such characters may be among
recent plants. Ina certain number of cases, discovery of the fructification has
come to our aid, and where sori are found we can have no more doubt as to the
specimens belonging to true Ferns. The work of Stur and Zeiller has been
especially valuable in this direction, and has revealed the interesting fact that a
great many of these early Ferns showed forms of fructification now limited to the
small order Marattiaceee. I think perhaps the predominance of this group has
been somewhat exaggerated, but at least there is no doubt that the marattiaceous
type was much more important then than now, though it by no means stood
alone. In certain cases the whole fern-plant can be built up. Thus Zeiller and
Renault have shown that the great stems known as Psaronius, the structure of
which is perfectly preserved, bore fronds of the Pecopteris form, and that similar
Pecopteris fronds produced the fructification of Asterotheca, which is of a marat-

16 REPORT—1896.

tiaceous character. Hence, for a good many Carboniferous and Permian forms
there is not the slightest doubt as to their fern-nature, and we can even form an
idea of the particular group of Ferns to which the affinity is closest.

I will say nothing more as to the true Ferns, though they present innumerable
points of interest, but will pass on at once to certain forms of even greater import-
ance to the comparative morphologist.

A considerable number of paleozoic plants are now known which present
characters intermediate between those of Ferns and Cycadew. I say present inter-
mediate characters, because that is a safe statement ; we cannot go further than
this at present, for we do not yet know the reproductive organs of the forms in
question,

In Lyginodendron, the vegetative organs of which are now completely known,
the stem has on the whole a cycadean structure ; the anatomy, which is preserved
with astonishing perfection, presents some remarkable peculiarities, the most
striking being that the vascular bundles of the stem have precisely the same
arrangement of their elements as is found in the leaves of existing Cycads, but
nowhere else among living plants. The roots also, though not unlike those of
certain ferns in their primary organisation, grew in thickness by means of
cambium, like those of a Gymnosperm. On the other hand, the leaves of
Lyginodendron are typical fern-fronds, having the form characteristic of the
genus Sphenopteris, and being probably identical with the species S. Haninghausi.
Their minute structure is also exactly that of a fern-frond, so that no botanist
would doubt that he had to do with a Fern if the leaves alone were before him.

This plant thus presents an unmistakable combination of cyecadean and fern-
like characters. Another and more ancient genus, Heterangiwm, agrees in many
details with ZLyginodendron, but stands nearer the ferns, the stem in its primary
structure resembling that of a Gileichenia, though it grows in thickness like a
cycad. These intermediate characters led Professor Williamson and myself to
the conclusion that these two genera were derived from an ancient stock of Ferns,
combining the characters of several of the existing families, and that they had
already considerably diverged from this stock in a cycadean direction. I believe
that recent investigations, of which I hope we shall hear more from Mr. Seward, ~
tend to supply a link between Lyginodendron and the more distinctly cycadean
stem known as Cycadoxylon.

Heterangium first appears in the Burntisland beds, at the base of the carboni-
ferous system; from a similar horizon in Silesia, Count Solms-Laubach has de-
scribed another fossil, Protopitys Bucheana, the vegetative structure of which also
shows, though in a different form, a striking union of the characters of Ferns and
Gymnosperms. Count Solms shows that this genus cannot well be included among
the Lyginodendre, but must be placed in a family of its own, which, to use his own
words, ‘ increases the number of extinct types which show a transition between the
characters of Filicineze and of Gymnosperms, and which thus might represent the
descendants in different directions of a primitive group common to both.’ ;

Another intermediate group, quite different from either of the foregoing, is
that of the Medullosew, fossils most frequent in the Upper Carboniferous and Per-
mian strata. The stems haye a remarkably complicated structure, built up of a
number of distinct rings of wood and bast, each growing by its own cambium.
Whether these rings represent so many separate primary cylinders, like those of an
ordinary polystelic Fern, or are entirely the product of anomalous secondary
growth, is still an open question, on which we may expect more light from the
investigations of Count Solms. In any case, these curious stems (which certainly
suggest in themselves some relation to Cycadew) are known to have borne the
petioles known as Myeloaylon which have precisely the structure of cycadean
petioles.*

Renault has further brought forward convincing evidence that these Myeloxylon
petioles terminated in distinctly fern-like foliage, referable to the form-genera

' Bot. Zeitung, 1893, p. 207.
? Seward, Annals of Botany, vol. vii. p. 1.

TRANSACTIONS OF SECTION K. 1 /

Alethopteris and Neuropteris. WHence it is evident that the fronds of these types,

like some specimens of Sphenopteris, cannot be accepted as true Ferns, but may

a cima suspected of belonging to intermediate groups between Ferns and
cads.

: It is not likely (as has been repeatedly pointed out elsewhere) that any of these
intermediate forms are really direct ancestors of our existing Cycads, which
certainly constitute only a small and insignificant remnant of what was once a
great class, derived, as I think the evidence shows, from fern-like ancestors,
probably by several lines of descent.

One of the greatest discoveries in fossil botany was undoubtedly that of the
Cordaiteee—a fourth family of Gymnosperms, quite distinct from the three now
existing, though having certain points in common with all of them. They are
much the most ancient of the four stocks, extending back far into the Devonian.
Nearly all the wood of Carboniferous age, formerly referred to Coniferse under the
name of Dado.wylon or Araucarioxylon, belonged to these plants. Thanks chiefly
to the brilliant researches of Renault and Grand’ Eury, the structure of these fine
trees is now known with great completeness. The roots and stems have a coniferous
character, but the latter contain a large, chambered pith different from anything in
that order. The great simple lanceolate or spatulate leaves, sometimes a yard
long, were traversed by a number of parallel vascular bundles, each of which has
the exact structure of a foliar bundle in existing Cycader, This type of vascular
bundle is evidently one of the most ancient and persistent of characters, Both
the male and female flowers (Cordaianthus) are well preserved in some cases. The
morphology of the former has not yet been cleared up, but the stamen, consisting
of an upright filament bearing 2-4 long pollen-sacs at the top, is quite unlike
anything in Cycadew; a comparison is possible either with Gingko or with the
Gnetacer.

In the female flowers—small cones—the axillary ovules appear to have two
integuments, a character which resembles Gnetacew rather than any other Gymno-
sperms. Renault’s famous discovery of the prothallus in the pollen-grains of
Cordaites indicates the persistence of a cryptogamic character; but it cannot be
said that the group as a whole bears the impress of primitive simplicity, though it
certainly combines in a remarkable way the characters of the three existing orders
of the Gymnosperms.

There is one genus, Poroxylon, fully and admirably investigated by Messrs.
Bertrand and Renault, which from its perfectly preserved vegetative structure (and
at present nothing else is known) appears to occupy an intermediate position
between the Lyginodendrese and the Cordaitez. he anatomy of the stem is
almost exactly that of Lyginodendron, the resemblance extending to the minutest
details, while the leaves seem to closely approach those of Cordaites. Poroxylon
is at present known only from the Upper Carboniferous, so we cannot regard it as
in any way representing the ancestors of the far more ancient Cordaitew. The
genus suggests, however, the possibility that the Cordaitew and the Cycadex
fialng the latter term in its wide sense) may have had a common origin among
corms belonging to the filicinean stock. It is also possible that the Cordaites, or
plants allied to them, may in their turn have given rise to both Conifers and
Gnetacere.

It is unfortunate that at present we do not know the fructification of any of
the fossil plants which appear to be intermediate between ferns and Gymnosperms.
Sooner or later the discovery will doubtless be made in some of these forms, and
most interesting it will be. M. Renault's Cycadospadix from Autun appears to
show that very cycad-like fructifications already existed in the later Carboniferous
period, and numerous isolated seeds point in the same direction, but we do not
know to what plants they belonged.

I think we may say that such definite evidence as we already possess decidedly
points in the direction of the origin of the Gymnosperms generally from plants of
the Fern series rather than from a lyecopodiaceous stock, i

I must say a few words before concluding on the cycad-like fossils which are
so striking a feature of mesozoic rocks, although I feel that this is a subject with

18 REPORT—1896,

which my friend Mr. Seward is far more competent to deal. Both leaves and
trunks of an unmistakably cycadean character are exceedingly common in many
mesozoic strata, from the Lias up to the Lower Cretaceous. In some cases the
structure of the stem is preserved, and then it appears that the anatomy as well
as the external morphology is, on the whole, cycadean, though simpler, as regards
the course of the vascular bundles, than that of recent representatives of the
group.

- dance to say, however, it is only in the rarest cases that fructifications of a
truly cycadean type have been found in association with these leaves and stems. In
most cases, when the fructification is accurately known, it has turned out to he of a
type totally different from that of the true Cyeadew, and much more highly organ-
ised, This is the form of fructification characteristic of Bennettites, a most remark-
able group, the organisation of which was first revealed by the researches of
Carruthers, afterwards extended by those of Solms-Laubach and Lignier. The
venus evidently had a great geological range, oxtending from the Middle Odlite (or
perhaps even older strata) to the Lower Greensand. Probably, all botanists are
agreed in attributing cycadean affinities to the Bennettitew, and no doubt they
are justified in this. Yet the cycadean characters are entirely vegetative and anato-
mical ; the fructification is as different as possible from that of any existing cycad,
or, for that matter, of any existing Gymnosperm. At present, only the female
flower is accurately known, though Count Solms has found some indications of
anthers in certain Italian specimens. The fructification of the typical species, B.
Gibsonianus, which is preserved in marvellous perfection in the classical specimens
from the Isle of Wight, terminates a short branch inserted between the leaf-bases,
and consists of a fleshy Hi Sr bearing a great number of seeds seated on a long
pedicel with barren scales between them. The whole mass of seeds and inter-
mediate scales is closely packed into a head, and is enclosed by a kind of pericarp
formed of coherent scales, and pierced by the micropylar terminations of the erect
seeds, Outside the pericarp, again, is an envelope of bracts which have precisely
the structure of scale-leaves in cycads. The internal structure of the seeds is per-
fectly preserved, and strange to say, they are nearly, if not quite, exalbuminous,
practically the whole cavity being occupied by a large dicotyledonous embryo.

This extraordinary fructification is entirely different from that of any other
known group of plants, recent or fossil, and characterises the Bennettites, as a
family perfectly distinct from the Oycades, though probably, as Count Solms-
Laubach suggests, having’a common origin with them at some remote period. The
Bennettitese, while approaching Angiosperms in the complexity of their fruit,
retain a filicinean character in their ramenta, which are quite like those of ferns,
and different from any other form of hair found in recent Cycadew. Probably the
bennettitean and cycadean series diverged from each other at a point not far re-
moved from the filicinean stock common to both. 4

I hope that the hasty sketch which I have attempted of some of the indications
of descent afforded by modern work on fossil plants may have served to illustrate
the importance of the questions involved and to bring home to botanists the fact
that phylogenetic problems can no longer be adequately dealt with without taking
into account the historical evidence which the rocks afford us.

Before leaving this subject I desire to express the great regret which all
botanists mus: feel at the recent loss of one of the few men in England who have
carried on original work in fossil botany. At the last meeting of the Association
we had to lament the death, at a ripe old age, of a great leader in this branch of
science, Professor W. C. Williamson. Only a few weeks ago we heard of the
premature decease of Thomas Hick, for many years his demonstrator and
colleague. Mr Hick profited by his association with his distinguished chief, and
made many valuable original contributions to paleeobotany (not to mention other
parts of botanical science), among which I may especially recall his work, in
conjunction with Mr. Cash, on <Astromyelon (now known to be the root of
Calamites), on the leayes and on the primary structure of the stem in Calamites, on
the structure of Calamostachys, on the root of Lyginodendron, and on a new fossil
probably allied to Stigmaria, His loss will leave a gap in the too thin ranks of

TRANSACTIONS OF SECTION K. 19

fossil-botanists; but we may hope that the subject, now that its importance is

beginning to be appreciated, will be taken up by a new generation of enthusiastic
investigators.

ConcLusion.

To my mind there is a wonderful fascination in the records of the far-distant
ast in which our own origin, like that of our distant cousins the plants, lies
idden. If any fact is brought home to us by the investigations of modern

biology, it is the conviction that all life is one: that, as Nageli said, the distance
from man to the lowest bacterium is less than the distance from the lowest bac-
terium to non-living matter.

In all studies which bear on the origin and past history of living things there

is an element of human interest—

* Hence, in a season of calm weather,
Though inland far we be,
Our souls have sight of that immortal sea
Which brought us hither,’

The problems of descent, though strictly speaking they may often prove insoluble,
will never lose their attraction for the scientifically guided imagination.

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