Frank Richard Stockton - "Round about Rambles in Lands of Fact and Fancy"

Arthur Thomas Quiller Couch - "Green Bays. Verses and Parodies"

H. G. Wells - "Certain Personal Matters"

Joseph Conrad - "The Nigger Of The Narcissus"

Books of The Times: Perfect Neighbors, Perfect Strangers
Author Solutions, a publisher of print-on-demand books, has acquired Xlibris, a rival self-publisher, expanding its footprint in one of the fastest-growing segments of publishing.

Arts, Briefly: Self-Publishing Company Acquires Its Rival
In Michel Faber’s novel based on the Prometheus myth, a linguist discovers what appears to be a fifth Gospel, a new account of the Crucifixion.

Books of The Times: A 5th Gospel Can Be Like a 5th Wheel
An independent publisher said it was negotiating to release Herman Rosenblat’s discredited memoir, “Angel at the Fence,” as fiction.

Thomas Henry Huxley - Lay Sermons, Addresses and Reviews

T >> Thomas Henry Huxley >> Lay Sermons, Addresses and Reviews




I may say, therefore, that the sixth segment is like the others in plan,
but that it is modified in its details.

The first segment is like the others, so far as its ring is concerned,
and though its appendages differ from any of those yet examined in the
simplicity of their structure, parts corresponding with the stem and one
of the divisions of the appendages of the other segments can be readily
discerned in them.

Thus it appears that the lobster's tail is composed of a series of
segments which are fundamentally similar, though each presents peculiar
modifications of the plan common to all. But when I turn to the fore
part of the body I see, at first, nothing but a great shield-like shell,
called technically the "carapace," ending in front in a sharp spine, on
either side of which are the curious compound eyes, set upon the ends of
stout moveable stalks. Behind these, on the under side of the body, are
two pairs of long feelers, or antennae, followed by six pairs of jaws,
folded against one another over the mouth, and five pairs of legs, the
foremost of these being the great pinchers, or claws, of the lobster.

It looks, at first, a little hopeless to attempt to find in this complex
mass a series of rings, each with its pair of appendages, such as I have
shown you in the abdomen, and yet it is not difficult to demonstrate
their existence. Strip off the legs, and you will find that each pair is
attached to a very definite segment of the under wall of the body; but
these segments, instead of being the lower parts of free rings, as in
the tail, are such parts of rings which are all solidly united and bound
together; and the like is true of the jaws, the feelers, and the
eye-stalks, every pair of which is borne upon its own special segment.
Thus the conclusion is gradually forced upon us, that the body of the
lobster is composed of as many rings as there are pairs of appendages,
namely, twenty in all, but that the six hindmost rings remain free and
moveable, while the fourteen front rings become firmly soldered
together, their backs forming one continuous shield--the carapace.

Unity of plan, diversity in execution, is the lesson taught by the study
of the rings of the body, and the same instruction is given still more
emphatically by the appendages. If I examine the outermost jaw I find it
consists of three distinct portions, an inner, a middle, and an outer,
mounted upon a common stem; and if I compare this jaw with the legs
behind it, or the jaws in front of it, I find it quite easy to see,
that, in the legs, it is the part of the appendage which corresponds
with the inner division, which becomes modified into what we know
familiarly as the "leg," while the middle division, disappears, and the
outer division is hidden under the carapace. Nor is it more difficult to
discern that, in the appendages of the tail, the middle division appears
again and the outer vanishes; while, on the other hand, in the foremost
jaw, the so-called mandible, the inner division only is left; and, in
the same way, the parts of the feelers and of the eye-stalks can be
identified with those of the legs and jaws.

But whither does all this tend? To the very remarkable conclusion that a
unity of plan, of the same kind as that discoverable in the tail or
abdomen of the lobster, pervades the whole organization of its skeleton,
so that I can return to the diagram representing any one of the rings of
the tail, which I drew upon the board, and by adding a third division to
each appendage, I can use it as a sort of scheme or plan of any ring of
the body. I can give names to all the parts of that figure, and then if
I take any segment of the body of the lobster, I can point out to you
exactly, what modification the general plan has undergone in that
particular segment; what part has remained moveable, and what has become
fixed to another; what has been excessively developed and metamorphosed,
and what has been suppressed.

But I imagine I hear the question, How is all this to be tested? No
doubt it is a pretty and ingenious way of looking at the structure of
any animal, but is it anything more? Does Nature acknowledge, in any
deeper way, this unity of plan we seem to trace?

The objection suggested by these questions is a very valid and important
one, and morphology was in an unsound state, so long as it rested upon
the mere perception of the analogies which obtain between fully formed
parts. The unchecked ingenuity of speculative anatomists proved itself
fully competent to spin any number of contradictory hypotheses out of
the same facts, and endless morphological dreams threatened to supplant
scientific theory.

Happily, however, there is a criterion of morphological truth, and a
sure test of all homologies. Our lobster has not always been what we see
it; it was once an egg, a semifluid mass of yolk, not so big as a pin's
head, contained in a transparent membrane, and exhibiting not the least
trace of any one of those organs, whose multiplicity and complexity, in
the adult, are so surprising. After a time a delicate patch of cellular
membrane appeared upon one face of this yolk, and that patch was the
foundation of the whole creature, the clay out of which it would be
moulded. Gradually investing the yolk, it became subdivided by
transverse constrictions into segments, the forerunners of the rings of
the body. Upon the ventral surface of each of the rings thus sketched
out, a pair of bud-like prominences made their appearance--the rudiments
of the appendages of the ring. At first, all the appendages were alike,
but, as they grew, most of them became distinguished into a stem and two
terminal divisions, to which, in the middle part of the body, was added
a third outer division; and it was only at a later period, that by the
modification, or abortion, of certain of these primitive constituents,
the limbs acquired their perfect form.

Thus the study of development proves that the doctrine of unity of plan
is not merely a fancy, that it is not merely one way of looking at the
matter, but that it is the expression of deep-seated natural facts. The
legs and jaws of the lobster may not merely be regarded as modifications
of a common type,--in fact and in nature they are so,--the leg and the
jaw of the young animal being, at first, indistinguishable.

These are wonderful truths, the more so because the zoologist finds them
to be of universal application. The investigation of a polype, of a
snail, of a fish, of a horse, or of a man, would have led us, though by
a less easy path, perhaps, to exactly the same point. Unity of plan
everywhere lies hidden under the mask of diversity of structure--the
complex is everywhere evolved out of the simple. Every animal has at
first the form of an egg, and every animal and every organic part, in
reaching its adult state, passes through conditions common to other
animals and other adult parts; and this leads me to another point. I
have hitherto spoken as if the lobster were alone in the world, but, as
I need hardly remind you, there are myriads of other animal organisms.
Of these, some, such as men, horses, birds, fishes, snails, slugs,
oysters, corals, and sponges, are not in the least like the lobster. But
other animals, though they may differ a good deal from the lobster, are
yet either very like it, or are like something that is like it. The cray
fish, the rock lobster, and the prawn, and the shrimp, for example,
however different, are yet so like lobsters, that a child would group
them as of the lobster kind, in contradistinction to snails and slugs;
and these last again would form a kind by themselves, in
contradistinction to cows, horses, and sheep, the cattle kind.

But this spontaneous grouping into "kinds" is the first essay of the
human mind at classification, or the calling by a common name of those
things that are alike, and the arranging them in such a manner as best
to suggest the sum of their likenesses and unlikenesses to other things.

Those kinds which include no other subdivisions than the sexes, or
various breeds, are called, in technical language, species. The English
lobster is a species, our cray fish is another, our prawn is another. In
other countries, however, there are lobsters, cray fish, and prawns,
very like ours, and yet presenting sufficient differences to deserve
distinction. Naturalists, therefore, express this resemblance and this
diversity by grouping them as distinct species of the same "genus." But
the lobster and the cray fish, though belonging to distinct genera, have
many features in common, and hence are grouped together in an assemblage
which is called a family. More distant resemblances connect the lobster
with the prawn and the crab, which are expressed by putting all these
into the same order. Again, more remote, but still very definite,
resemblances unite the lobster with the woodlouse, the king crab, the
water-flea, and the barnacle, and separate them from all other animals;
whence they collectively constitute the larger group, or class,
_Crustacea_. But the _Crustacea_ exhibit many peculiar features in
common with insects, spiders, and centipedes, so that these are grouped
into the still larger assemblage or "province" _Articulata_; and,
finally, the relations which these have to worms and other lower
animals, are expressed by combining the whole vast aggregate into the
sub-kingdom of _Annulosa_.

If I had worked my way from a sponge instead of a lobster, I should have
found it associated, by like ties, with a great number of other animals
into the sub-kingdom _Protozoa_; if I had selected a fresh-water polype
or a coral, the members of what naturalists term the sub-kingdom
_Caelenterata_ would have grouped themselves around my type; had a snail
been chosen, the inhabitants of all univalve and bivalve, land and
water, shells, the lamp shells, the squids, and the sea-mat would have
gradually linked themselves on to it as members of the same sub-kingdom
of _Mollusca_; and finally, starting from man, I should have been
compelled to admit first, the ape, the rat, the horse, the dog, into the
same class; and then the bird, the crocodile, the turtle, the frog, and
the fish, into the same sub-kingdom of _Vertebrata_.

And if I had followed out all these various lines of classification
fully, I should discover in the end that there was no animal, either
recent or fossil, which did not at once fall into one or other of these
sub-kingdoms. In other words, every animal is organized upon one or
other of the five, or more, plans, whose existence renders our
classification possible. And so definitely and precisely marked is the
structure of each animal, that, in the present state of our knowledge,
there is not the least evidence to prove that a form, in the slightest
degree transitional between any of the two groups _Vertebrata, Annulosa,
Mollusca_, and _Caelenterata_, either exists, or has existed, during that
period of the earth's history which is recorded by the geologist.
Nevertheless, you must not for a moment suppose, because no such
transitional forms are known, that the members of the sub-kingdoms are
disconnected from, or independent of, one another. On the contrary, in
their earliest condition they are all alike, and the primordial germs
of a man, a dog, a bird, a fish, a beetle, a snail, and a polype are, in
no essential structural respects, distinguishable.

In this broad sense, it may with truth be said, that all living animals,
and all those dead creations which geology reveals, are bound together
by an all-pervading unity of organization, of the same character, though
not equal in degree, to that which enables us to discern one and the
same plan amidst the twenty different segments of a lobster's body.
Truly it has been said, that to a clear eye the smallest fact is a
window through which the Infinite may be seen.

Turning from these purely morphological considerations, let us now
examine into the manner in which the attentive study of the lobster
impels us into other lines of research.

Lobsters are found in all the European seas; but on the opposite shores
of the Atlantic and in the seas of the southern hemisphere they do not
exist. They are, however, represented in these regions by very closely
allied, but distinct forms--the _Homarus Americanus_ and the _Homarus
Capensis_: so that we may say that the European has one species of
_Homarus_; the American, another; the African, another; and thus the
remarkable facts of geographical distribution begin to dawn upon us.

Again, if we examine the contents of the earth's crust, we shall find in
the latter of those deposits, which have served as the great burying
grounds of past ages, numberless lobster-like animals, but none so
similar to our living lobster as to make zoologists sure that they
belonged even to the same genus. If we go still further back in time,
we discover, in the oldest rocks of all, the remains of animals,
constructed on the same general plan as the lobster, and belonging to
the same great group of _Crustacea_; but for the most part totally
different from the lobster, and indeed from any other living form of
crustacean; and thus we gain a notion of that successive change of the
animal population of the globe, in past ages, which is the most striking
fact revealed by geology.

Consider, now, where our inquiries have led us. We studied our type
morphologically, when we determined its anatomy and its development, and
when comparing it, in these respects, with other animals, we made out
its place in a system of classification. If we were to examine every
animal in a similar manner, we should establish a complete body of
zoological morphology.

Again, we investigated the distribution of our type in space and in
time, and, if the like had been done with every animal, the sciences of
geographical and geological distribution would have attained their
limit.

But you will observe one remarkable circumstance, that, up to this
point, the question of the life of these organisms has not come under
consideration. Morphology and distribution might be studied almost as
well, if animals and plants were a peculiar kind of crystals, and
possessed none of those functions which distinguish living beings so
remarkably. But the facts of morphology and distribution have to be
accounted for, and the science, whose aim it is to account for them, is
Physiology.

Let us return to our lobster once more. If we watched the creature in
its native element, we should see it climbing actively the submerged
rocks, among which it delights to live, by means of its strong legs; or
swimming by powerful strokes of its great tail, the appendages of whose
sixth joint are spread out into a broad fan-like propeller: seize it,
and it will show you that its great claws are no mean weapons of
offence; suspend a piece of carrion among its haunts, and it will
greedily devour it, tearing and crushing the flesh by means of its
multitudinous jaws.

Suppose that we had known nothing of the lobster but as an inert mass,
an organic crystal, if I may use the phrase, and that we could suddenly
see it exerting all these powers, what wonderful new ideas and new
questions would arise in our minds! The great new question would be,
"How does all this take place?" the chief new idea would be, the idea of
adaptation to purpose,--the notion, that the constituents of animal
bodies are not mere unconnected parts, but organs working together to an
end. Let us consider the tail of the lobster again from this point of
view. Morphology has taught us that it is a series of segments composed
of homologous parts, which undergo various modifications--beneath and
through which a common plan of formation is discernible. But if I look
at the same part physiologically, I see that it is a most beautifully
constructed organ of locomotion, by means of which the animal can
swiftly propel itself either backwards or forwards.

But how is this remarkable propulsive machine made to perform its
functions? If I were suddenly to kill one of these animals and to take
out all the soft parts, I should find the shell to be perfectly inert,
to have no more power of moving itself than is possessed by the
machinery of a mill, when disconnected from its steam-engine or
water-wheel. But if I were to open it, and take out the viscera only,
leaving the white flesh, I should perceive that the lobster could bend
and extend its tail as well as before. If I were to cut off the tail, I
should cease to find any spontaneous motion in it; but on pinching any
portion of the flesh, I should observe that it underwent a very curious
change--each fibre becoming shorter and thicker. By this act of
contraction, as it is termed, the parts to which the ends of the fibre
are attached are, of course, approximated; and according to the
relations of their points of attachment to the centres of motion of the
different rings, the bending or the extension of the tail results. Close
observation of the newly opened lobster would soon show that all its
movements are due to the same cause--the shortening and thickening of
these fleshy fibres, which are technically called muscles.

Here, then, is a capital fact. The movements of the lobster are due to
muscular contractility. But why does a muscle contract at one time and
not at another? Why does one whole group of muscles contract when the
lobster wishes to extend his tail, and another group, when he desires to
bend it? What is it originates, directs, and controls the motive power?

Experiment, the great instrument for the ascertainment of truth in
physical science, answers this question for us. In the head of the
lobster there lies a small mass of that peculiar tissue which is known
as nervous substance. Cords of similar matter connect this brain of the
lobster, directly or indirectly, with the muscles. Now, if these
communicating cords are cut, the brain remaining entire, the power of
exerting what we call voluntary motion in the parts below the section is
destroyed; and on the other hand, if, the cords remaining entire, the
brain mass be destroyed, the same voluntary mobility is equally lost.
Whence the inevitable conclusion is, that the power of originating these
motions resides in the brain, and is propagated along the nervous cords.

In the higher animals the phaenomena which attend this transmission have
been investigated, and the exertion of the peculiar energy which resides
in the nerves has been found to be accompanied by a disturbance of the
electrical state of their molecules.

If we could exactly estimate the signification of this disturbance; if
we could obtain the value of a given exertion of nerve force by
determining the quantity of electricity, or of heat, of which it is the
equivalent; if we could ascertain upon what arrangement, or other
condition of the molecules of matter, the manifestation of the nervous
and muscular energies depends, (and doubtless science will some day or
other ascertain these points,) physiologists would have attained their
ultimate goal in this direction; they would have determined the relation
of the motive force of animals to the other forms of force found in
nature; and if the same process had been successfully performed for all
the operations which are carried on in, and by, the animal frame,
physiology would be perfect, and the facts of morphology and
distribution would be deducible from the laws which physiologists had
established, combined with those determining the condition of the
surrounding universe.

There is not a fragment of the organism of this humble animal, whose
study would not lead us into regions of thought as large as those which
I have briefly opened up to you; but what I have been saying, I trust,
has not only enabled you to form a conception of the scope and purport
of zoology, but has given you an imperfect example of the manner in
which, in my opinion, that science, or indeed any physical science, may
be best taught. The great matter is, to make teaching real and
practical, by fixing the attention of the student on particular facts;
but at the same time it should be rendered broad and comprehensive, by
constant reference to the generalizations of which all particular facts
are illustrations. The lobster has served as a type of the whole animal
kingdom, and its anatomy and physiology have illustrated for us some of
the greatest truths of biology. The student who has once seen for
himself the facts which I have described, has had their relations
explained to him, and has clearly comprehended them, has, so far, a
knowledge of zoology, which is real and genuine, however limited it may
be, and which is worth more than all the mere reading knowledge of the
science he could ever acquire. His zoological information is, so far,
knowledge and not mere hearsay.

And if it were my business to fit you for the certificate in zoological
science granted by this department, I should pursue a course precisely
similar in principle to that which I have taken to-night. I should
select a fresh-water sponge, a fresh-water polype or a _Cyanaea_, a
fresh-water mussel, a lobster, a fowl, as types of the five primary
divisions of the animal kingdom. I should explain their structure very
fully, and show how each illustrated the great principles of zoology.
Having gone very carefully and fully over this ground, I should feel
that you had a safe foundation, and I should then take you in the same
way, but less minutely, over similarly selected illustrative types of
the classes; and then I should direct your attention to the special
forms enumerated under the head of types, in this syllabus, and to the
other facts there mentioned.

That would, speaking generally, be my plan. But I have undertaken to
explain to you the best mode of acquiring and communicating a knowledge
of zoology, and you may therefore fairly ask me for a more detailed and
precise account of the manner in which I should propose to furnish you
with the information I refer to.

My own impression is, that the best model for all kinds of training in
physical science is that afforded by the method of teaching anatomy, in
use in the medical schools. This method consists of three
elements--lectures, demonstrations, and examinations.

The object of lectures is, in the first place, to awaken the attention
and excite the enthusiasm of the student; and this, I am sure, may be
effected to a far greater extent by the oral discourse and by the
personal influence of a respected teacher than in any other way.
Secondly, lectures have the double use of guiding the student to the
salient points of a subject, and at the same time forcing him to attend
to the whole of it, and not merely to that part which takes his fancy.
And lastly, lectures afford the student the opportunity of seeking
explanations of those difficulties which will; and indeed ought to,
arise in the course of his studies.

But for a student to derive the utmost possible value from lectures,
several precautions are needful.

I have a strong impression that the better a discourse is, as an
oration, the worse it is as a lecture. The flow of the discourse carries
you on without proper attention to its sense; you drop a word or a
phrase, you lose the exact meaning for a moment, and while you strive to
recover yourself, the speaker has passed on to something else.

The practice I have adopted of late years, in lecturing to students, is
to condense the substance of the hour's discourse into a few dry
propositions, which are read slowly and taken down from dictation; the
reading of each being followed by a free commentary, expanding and
illustrating the proposition, explaining terms, and removing any
difficulties that may be attackable in that way, by diagrams made
roughly, and seen to grow under the lecturer's hand. In this manner you,
at any rate, insure the co-operation of the student to a certain extent.
He cannot leave the lecture-room entirely empty if the taking of notes
is enforced; and a student must be preternaturally dull and mechanical,
if he can take notes and hear them properly explained, and yet learn
nothing.

What books shall I read? is a question constantly put by the student to
the teacher. My reply usually is, "None: write your notes out carefully
and fully; strive to understand them thoroughly; come to me for the
explanation of anything you cannot understand; and I would rather you
did not distract your mind by reading." A properly composed course of
lectures ought to contain fully as much matter as a student can
assimilate in the time occupied by its delivery; and the teacher should
always recollect that his business is to feed, and not to cram the
intellect. Indeed, I believe that a student who gains from a course of
lectures the simple habit of concentrating his attention upon a
definitely limited series of facts, until they are thoroughly mastered,
has made a step of immeasurable importance.

But, however good lectures may be, and however extensive the course of
reading by which they are followed up, they are but accessories to the
great instrument of scientific teaching--demonstration. If I insist
unweariedly, nay fanatically, upon the importance of physical science as
an educational agent, it is because the study of any branch of science,
if properly conducted, appears to me to fill up a void left by all other
means of education. I have the greatest respect and love for literature;
nothing would grieve me more than to see literary training other than a
very prominent branch of education: indeed, I wish that real literary
discipline were far more attended to than it is; but I cannot shut my
eyes to the fact, that there is a vast difference between men who have
had a purely literary, and those who have had a sound scientific,
training.

Copyright (c) 2007. topmasterworks.com. All rights reserved.