NATURE

FHROl ftO 01

• •

MOSQUITO
fAnophe/es Maculipennis)

KERR

^

R APHS

• ARTHUR: --E. SMITH. • "

THE LIBRARY

OF

THE UNIVERSITY
OF CALIFORNIA

PRESENTED BY

PROF. CHARLES A. KOFOID AND
MRS. PRUDENCE W. KOFOID

BY THE SAME AUTHOR.

Nature— Curious and
Beautiful.

With Eighty-nine Illustrations. Crown
Svo, cloth gilt, 3s. 6(2.

Hidden Beauties of
Nature.

With Fifty-nine Illustrations. Crown
Svo, cloth gilt, 2s. 6d.

LONDON

THE RELIGIOUS TRACT SOCIETY
4 BOUVEEIE STREET, E.G.

NATURE— THROUGH MICROSCOPE
AND CAMERA

* Oh, there are curious things of which men know
As yet but little ! Secrets lying hid
Within all natural objects. Be they shells,
Which ocean flingeth off her billows,
Or the low sand or flowers, or trees, or grasses,
Covering the earth ; rich metals or bright ores
Beneath the surface. He who findeth out
Those secret things hath a fair right to gladness;
For he hath well performed, and doth awake
Another note of praise on Nature's harp
To hymn her Great Creator.'

'To the Natural Philosopher there is no natural object that is
unimportant or trifling ; from the least of Nature's works he may
learn the greatest lessons.' — SIB J. F. W. HEBSCHEL.

FIG. I.
POLYCYSTINA FROM BARBADOS.

X40

NATURE

THROUGH

MICROSCOPE & CAMERA

BY

RICHARD KERR, F.Q.S., F.R.A.S

AUTHOR OF 'NATURE— CURIOUS AND BEAUTIFUL,'
'HIDDEN BEAUTIES OF NATURE,' ETC.

WITH SIXTY-FIVE PHOTO-MICROGRAPHS

BY
ARTHUR E. SMITH

TONGUE OF RHYNGIA

X25.

SECO.VD IMPRESS /ON

LONDON

THE RELIGIOUS TRACT SOCIETY

4 Bouverie St. & 65 St. Paul's Churchyard
1909

INTRODUCTION

BY G, SIMS WOODHEAD, M.A. M.D.,

PROFESSOR OF PATHOLOGY, CAMBRIDGE.

who have once attempted to catch
a glimpse of the wonderful secrets that
Nature will unveil to the earnest and discreet
searcher can never again look upon things as
common or of little importance because they
do not display to the eye of the superficial
observer the beauties that lie hidden under an
unattractive appearance or are shrouded in size
so minute that the ordinary eye is incapable of
discerning their exquisite plan and detail.

The ingenious and beautifully finished works
projected by the human brain and brought into
being by the human hand attract our attention
and compel our admiration. We are constrained
to admit that the telescope, the microscope, the

S DELICATE TRACERY OF DIATOMS

steam-engine or the watch, to say nought of those
rare works of art that from age to age have been
described as perfect of their kind, are wondrously
beautiful; and beautiful they are, but in com-
parison with some of the exquisite objects
subjected to the photographer's art in the follow-
ing pages they are indeed coarse and crude.
The writing of the Lord's Prayer on a surface
no larger in area than that covered by a three-
penny piece is looked upon as a great piece of
penmanship, but how the lines so made suffer
by comparison with some of the objects here
photographed. The delicate tracery of the
Heliopelta metii (Fig. 3), of the beautiful
diatom from Bori, in Hungary (Fig. 5), or of
the Coscinodiscus bi-angulatus (Fig. 4), can
only be properly ' resolved ' or brought into
view by the use of magnifications so great that
if applied to an object one inch in length they
would make it appear to be nearly sixty-eight
yards long, or would magnify the finest, most
beautiful silk that the spinner and weaver can
produce into something far rougher than a
wattle fence or a fabric woven of ship's cables.

FIG. 3.
DIATOM, HELIOPELTA METII.

\to face /. 7.

WIDE RANGE OF SUBJECTS 7

It would be mere repetition of what the author
has put down in description and explanation of
the plates to give further illustration of the
contrast that obtains between man's crude
handiwork and the many beautiful objects that
have here been brought under the lens of the
photographic camera.

And such a camera! I have seen many
collections of micro-photographs, and I have
examined many of the microscopic objects here
delineated, but never before have I fully
realised either the beauty of the objects them-
selves or the possibilities bound up in the
method by which these beauties have been
reproduced, and so rendered accessible to others
than those skilled in the use of the microscope.

The author and artist have gone over a wide
range of subjects, and have selected excellent
examples from each section of this range, and
any one who will take the trouble to examine a
single one of the photographs will be anxious
to cover the whole ground. When he has so
gone over this ground he should, if he is an
observant and thinking man, arise from the

8 THE VERY 'GARMENT OF GOD'

contemplation of these structures filled with
wonder at their perfection and with reverence
for the Power that conceived and brought about
their construction. No one can believe that
such things were created accidentally or by
chance; law appears in every organism, care
and design in every detail. Here is something
more than a mere crystallisation of like particles
from a liquid of a specific composition, wonderful
though that process is. Here we have thou-
sands upon thousands of exquisite forms each
one accurately reproduced or modified to meet
slightly altered conditions and to fit into
slightly altered surroundings. We have dif-
ferent forms of living matter from plants and
animals, we have dead or inorganic matter
snatched from its dead mass and converted by
this living matter into wondrously beautiful
structures. Can we believe that behind all this
design there is no great designer — that, in
fact, this is not the very ' garment of God ' ?
An honest attempt to get at the truth is never
to be feared. Truth is truth, and may always
be sought fearlessly. Truth can never turn out

EVIDENCE OF DESIGN g

anything but truth, and those who are engaged
in the investigation of natural phenomena have
little fear that anything we learn concerning
these phenomena can have any permanent
influence in undermining the essentials of our
religious belief.

It is sometimes maintained that the study of
natural science has a tendency to render men
less earnest in their study of religion; indeed,
many people look upon a knowledge of natural
science and a study of ' evolution * as being
incompatible with the existence of a religious
faith. Why should we abstain from studying
the marvellous works that are around us on
every side, even though we cannot expect to
understand them all ? ' Never let what you
know be disturbed by what you don't know/
In many cases it is impossible for us to follow
the process of evolution and growth of God's
wonderful works. Do we say that they do not
exist because we do not understand them ?
Should we not rather accept them in all their
beauty and with all their evidence of design as
an indication that there is a designer? If ia

10 A GREAT REASONING POWER

these material things we accept what appeals
to our natural senses and take much more for
granted, are we justified in taking the position
of the agnostic, and rejecting everything of the
spiritual life that we cannot understand ?
Should it not be maintained that the more we
become convinced of our ignorance concerning
natural phenomena the more ready shall we be
to accept all that is good and beautiful in
Christ (and Christianity), without insisting on
a full understanding by our finite minds of
much that He taught and did ?

Even those phenomena which we look upon
as every-day occurrences are to many of us
almost sealed books. We say that we know
all about them, — but do we ? We have merely
scratched the surface of such knowledge ; we
have not reached the heart of it. We know little
more of the causes, of the forces that are at
work than we know of some of the miracles
that were recorded nearly a couple of thousand
years ago. Behind all these beautiful works
there appears to be a great reasoning Power,
a Power that controls, One infinitely above our

to face p. 10.

FIG. 4.
PART OF A DIATOM, COSCINODISCUS BI-ANGULATUS.

x 1750.

{see page in.

BEYOND OUR COMPREHENSION II

understanding. Such a thought as this must
recur to every one who is dealing with Nature's
problems. Let me give an example, one often
used. I have had to study, as have all doctors,
the process of healing. Here one sees how in
a short time after the infliction of a wound a
series of phenomena of wonderful beauty but
of great complexity are manifested. First,
blood, or some of its component parts, forms
a temporary stop-gap, filling up the wound
from top to bottom ; then the wounded tissues
in the immediate neighbourhood of such tem-
porary stop-gap begin to undergo change : they
multiply, forming new, embryonic, or imperfectly
developed tissues. After a time these young
tissues, at first pierced by numerous new blood-
vessels, become fully developed, and the gap
is filled up with permanent tissue. If we look
at these processes merely from the outside and
from the purely materialistic point of view, we
may say that these living cells multiplying and
forming new tissues are bringing about the heal-
ing of the wound. But are we much nearer any
explanation of what lies behind ? We are com-

12 HOW LITTLE WE KNOW

pelled to confess that here are factors beyond
our comprehension. We say that these living
tissues are doing certain things, but we don't
know how or why they live, what they are
doing or how they do it. We may attempt
to explain life as a chemical or a physical
process, or as a combination of such processes,
but there always comes a point at which we
get beyond our depth and we have to fall back
on what we call vitality, and we pretend to
explain things by using terms which seem to
convey more than we really understand. We
have learnt a few facts, a few elementary details
concerning the marvels of Nature's laboratory,
but the more we learn the more must we be
impressed by the fact that above all that we
can see and beyond all that we can understand
there is a great power, a power which pervades,
moves, controls, and guides. Sometimes in our
intellectual conceit we may claim that we are
able to explain all things of which we have
had some experience, but if we will only be
honest with ourselves we find that our ex-
planations are not explanations at all. We

THE MACHINERY OF NATURE 13

are merely recording observations or express-
ing opinions, often very ill-founded. We are
not going to the real centre of things. We
are no doubt learning something of the
machinery of Nature and of the world, yet
in our hearts we know that if we leave out
God we have nothing left for the power that
guides, controls, and pervades that machinery.
Now and again we may be satisfied with
partial, and what are called natural explanations.
Far more frequently, however, we know that we
are not satisfied. We know, indeed, that God
is necessary to us, and that He must reign in
the world and in us before we can have any
sense of satisfaction in our existence. It has
often been said that intellectual conceit tends
to unbelief — a conceit more characteristic even
of the age just passed than of the present
generation. In former years, with the sudden
opening out of our knowledge of natural
phenomena there has always been a tendency
on the part of those who studied Nature, and
who tried to wrest from her her hidden
treasures, to accept nothing that they could

14 WEISMANN'S WORDS

not explain as a result of their own observa-
tion and deduction and for which they could
not find an immediate and demonstrable cause.
Men have wrestled long and patiently with
Nature that they might wring from her her
secrets; they have built up schemes and
systems, and in the end have come to think
that anything that cannot be fitted into one
of these systems must be useless and may be
thrown aside. They have said we have for
long enough accepted authority as our guide,
and it would seem that the agnosticism of
to-day, or of yesterday rather, may be accepted
as a reaction against doctrines and dogmas
based solely upon, and supported by, what was
termed authority.

Let those who are afraid of the teachings
of natural science take to heart Weismann's
words : ' Although I regard the doctrine of
descent as proved, and hold it to be one of
the greatest acquisitions of human knowledge,
I must repeat that I do not mean to say that
everything is clear in regard to the evolution
of the living world. On the contrary, I believe

LAW'S OF NATURE 15

that we still stand merely on the threshold
of investigation, and that our insight into the
mighty process of evolution, which has brought
about the endless diversity of life upon our
earth, is still very incomplete in relation to
what may yet be found out, and that, instead
of being vainglorious, our attitude should be
one of modesty. We may well rejoice over
the great step forward which the dominant
recognition of the evolution theory implies, but
we must confess that the beginnings of life
are as little clear to us as those of the solar
system. But we can do this at least : we
can refer the innumerable and wonderful in-
terrelations of the organic cosmos to their
causes — common descent and adaptation — and
we can try to discover the ways and means
which have co-operated to bring the organic
world to the state in which we know it. ...
We shall see that the recognition of a
law-governed evolution of the organic is not
more prejudicial to true religion than is the
revolution of the earth round the sun.'

We may learn something from this book of

16 CREATOR'S MANIFESTATIONS

the laws of Nature. But we must always re-
member that what we call the laws of Nature
are merely a codification of our own experience
and observation. Those who will study such
laws and the basis on which they are founded
will, we believe, feel bound to accept them as
additional evidence of the existence of God,
with whom rest all powers of law and order
and to whom the supernatural is unknown,
though He may know and make manifest
many things which may not accord with our
finite ideas of the orderly, and may not fall
in with our conception of the natural.

-

to face pige 17.

FIG. 5.

DIATOM, FROM BOKI, HUNGARY,
X IOOO.

[set- page no.

AUTHOE'S INTRODUCTION

CHARLES KINGSLEY has said, <I have
^^ seen the cultivated man craving for
travel, and for success in life, pent up in the
drudgery of London work, and yet keeping his
spirit calm, and perhaps his morals all the
more righteous, by spending over his micro-
scope evenings which would too probably have
been gradually wasted at the theatre.'

This is strong testimony to the value of the
microscope alone as an entertaining and civilising
instrument. But the value of the instrument is
increased enormously by the addition of the
photographic camera. It is not at all necessary
to have a huge camera like that represented in
the illustration (Fig. 8). But of this we shall
say something later.

2 11

18 INTELLECTUAL RECREATION

The uppermost thought in the minds of
those who engage in photo-micrography, even
in an elementary way, is, I fancy, What a vast
amount of intellectual pleasure people miss
who have no knowledge of these instruments,
people too who could well afford to have them,
and who, if so inclined, could use them with
advantage in quarters where valuable time and
money are spent at ' Bridge,' and where the
powers of conversation rise no higher than in
ecstatic admiration of some fancy dog.

£ To Amuse, and not to Educate,' is an
announcement we see on the hoardings. It
expresses the spirit of the times in England.
Amusement is the order of the day in dear old
England ; and other nations love to have it so,
because the more we ' fool away ' our time the
more they employ their time and talents in
raising the intellectual status of their countries,
and as a result their commercial prosperity
follows. They are to be commended, while our
case is to be deplored.

It is not hinted for one moment that games
and amusements should be abolished; such a

A NATION'S PROSPERITY 19

suggestion would be absurd. But we cannot
shut our eyes to the fact that there can be too
much of the amusement fetich. It is overdone,
and its devotees act as if the only aim in life
is to be amused. The prosperity of the nation
does not depend upon the amount of amusement
that can be crammed into our lives, but upon
the intellectual attainments of the units that
make up the nation.

There are hundreds of thousands of people
in certain counties whose whole conversation
is permeated with football and cricket language,
showing the uppermost and paramount thoughts
in their minds.

It is not at all unlikely that this ' amusement
and not education ' desire is the cause of our
trade finding its way barred by better work
by other peoples, the cause of a good deal of
the want of employment among our working
classes, and the direct or indirect cause of an
amount of poverty and crime.

There are too many places of amusement in
our cities, too many trashy and pernicious
novels read in our free libraries, too much time

20 AN ENTHUSIAST'S USEFULNESS

given to games, both in the upper and in the
working classes, and not enough time nor
attention given to those forms of intellectual
recreation which improve the mind. Our boys
are made physically strong, but is the mental
development keeping pace with the physical?
If not, our nation will deteriorate.

We do not suggest photography through the
microscope as the remedy for existing defects,
but we think that the more our young men
take up intellectual pastimes the better it will
be for the nation. This is one of those
pastimes. It is not a selfish one. One
enthusiast is a centre of usefulness to others,
for he cannot keep to himself the enjoyment
he receives from the study of Nature's beauties
and wonders.

A section of the book is devoted to histo-
logical subjects intended specially for junior
medical students. At the same time the
illustrations and descriptions of all the sub-
jects in this particular department ought to be
familiar to every one. The enormous work
done by the heart, the wonderful structure

'WONDERFULLY MADE* 21

of a human hair, and that of the skin, &c.,
are all points well worth our attention. There
is nothing in Nature, so far as we know it,
that is more wonderful than the human body,
even considered from the histologist's stand-
point. Our education is incomplete if we
have shunned all knowledge of our own system
and its wonders.

The illustrations are entirely original. No-
thing from these negatives has ever been
published excepting the ' spider's foot,7 which
appeared in the July number of ' Knowledge '
as a whole-page illustration.

An expression of our indebtedness is due to
Mr. Henry Tavener for his new discovery and
his permission to illustrate it — the Mideopsis
orbicularis of pond water ; also to Dr. Joseph A.
Featherstone, of Tooting, for his kindness in
describing the histological details of several
sections illustrated.

RICHABD KERB.

BIBLIOGEAPHY

TN the preparation of these chapters use has
-•- been made of the works noted below. If
quotations have been made from any which
are not entered in the following list, the
omission is not intentional.

The Cambridge Natural History.

The Concise Knowledge Library.

Text-Book of Zoology. By GLAUS and SEDGWICK.

A Treatise on Zoology. Ed. by E. KAY LANKESTEB.

Text-Book of Physiology. By MCKENDRICK. (J. Macle-

hose & Sons.)
Text-Book of Human Physiology. By LANDOIS and

STIRLING.

Kirkes' Handbook of Physiology. (John Murray.)
The Microscope and its Revelations. Ed. by DR. DAL-

LINGER.

Systematic Botany. By WARMING and POTTER.
Microscopical Science. By COLE.
The Micrographic Dictionary.
Botany. By SACHS.
Diseases of Field and Garden Crops. By WORTHINGTON

G. SMITH.

23

24 BIBLIOGRAPHY

Students' Text-Book of Botany. By S. H. VINES.

Physiology of Plants.

Foraminifera. By CHAPMAN.

Diatomaceae. By MILLS.

The Microscope. By JABEZ HOGG.

The Animal Kingdom. By RYMEB JONES.

One Thousand Objects for the Microscope. By M. C.
COOKE.

Handbook of Practical Botany. STRASBURGER and HILL-
HOUSE.

A General System of Botany. MAOUT and DECAISNE.

CONTENTS

FADE

INTRODUCTION BY G. SIMS WOODHEAD, M.A., M.D., PRO-

FESSOB OP PATHOLOGY, CAMBRIDGE . .5

AUTHOR'S INTRODUCTION ... .17

BIBLIOGRAPHY . . . . . .23

CHAPTER

I. THE ILLUSTRATIONS AND HIGH POSSIBILITIES

WITH THE MICROSCOPE . . .29

II. PRACTICAL HINTS ON PHOTO-MICROGRAPHY . 37

III. FOSSIL RADIOLARIA (POLYCYSTINA) AND FORA-

MINIFERA . . . . .44

IV. RADUL3J, CIRRI OF BARNACLE AND SPINES OF

ECHINI ... 57

V. INSECT LIFE, PROBOSCIS OF BLOW-FLY AND EGGS

OF FLY . . . . .69

vi. BUTTERFLY'S TONGUE, EYE OF DYTISCUS, TONGUE

OF BEE AND LEG OF BEE ... 79
VII. MOSQUITO, AN INSECT NAVVY, AND RHYNGIA . 90

VIII. HEAD OF CRANE FLY AND ANTENNA OF

MELOLONTHA « 98

26 CONTENTS

CHAPTER I,AOB!

IX. DIATOMS ...... 103

X. SECTIONS OP WHEAT STEMS, AND DODDER ON

CLOVER ..... 112

XI. STING OF NETTLE, ARISTOLOCHIA GIGAS AND

CALAMUS ROTANG . . . .123

XII. BUD OF LILY, VIRGIN'S BOWER, AND PETIOLE

OF NUPHAR LUTEA .... 133

xin. SPRUCE FIR, BUTCHERS' BROOM AND HIPPURIS

VULGARIS ..... 139

XIV. HUMAN HAIR . .... 147

XV. HUMAN SKIN, HEART MUSCLE (HUMAN) AND

HUMAN BONE ..... 152

XVI. HUMAN LUNG, RED CORPUSCLES, HUMAN TOOTH 163

XVII. PARASITES OF IGUANA, BUFFALO, SHEEP, AND

BEE J THE CHEESE MITE . . . 170

XVIII. A WATER-MITE (MIDEOPSIS ORBICULARIS), SPIDER'S

FOOT AND WOLF SPIDER . . . 179

XIX. TETANUS (LOCKJAW) BACILLI J SCALES OF THE

SOLE ..... 187

XX. CIRCLET OF SCOLEX J SILK . . . 190

LIST OP ILLUSTBATIONS

FIG. PAGE

1. POLYCYSTINA FROM BARBADOS . ,' Frontispiece

2. TONGUE OF EHYNGIA , . . Title-page

3. DIATOM, HELIOPELTA METII . . 7

4. PART OF A DIATOM, COSCINODISCUS BI-ANGULATUS 10

5. DIATOM, FROM BORI, HUNGARY. . . 17

6. DIATOM, ACTINOCYCLUS EALFSII . . .32

7. FOCUSSING THE OBJECT IN THE MICROSCOPE . 37

8. FOCUSSING ON THE CAMERA SCREEN . . 37

9. POLYCYSTINA FROM BARBADOS ... 44

10. FORAMINIFERA . . . . .52

11. EADULA OF WHELK .... 56

12. EADULA OF WHELK . . . .57

13. EADULA OF LIMPET .... 61

14. CIRRI OF BARNACLE . . . .65

15. ECHINUS SPINE SECTION ... 68

16. PROBOSCIS OF BLOW-FLY . . . .71

17. PART OF FLY'S PROBOSCIS ... 74

18. EGGS OF HOUSE-FLY . . . .77

19. BUTTERFLY'S TONGUE . ... 80

20. PORTION OF BEETLE'S EYE. . . .81

21. FOOT OF WATER BEETLE (DYTISCUS MARGINALIS) 83

22. TONGUE OF HONEY BEE . . . .86

23. PART OF HONEY BEE'S HIND LEG . . 88

24. GNAT (CULEX PIPIENS) . . . .89

25. MOSQUITO (ANOPHELES MACULIPENNIS) . . 91

26. LARVA OF ANT-LION. . . . .94

27. EHYNGIA. 96

28. HEAD OF CRANE FLY . . . .99

29. ANTENNA OF COCKCHAFER (MELOLONTHA) . 101

30. DIATOM, NAVICULA LYRA .... 103

31. DIATOM, TRICERATIUM FAVUS . rr • 106

ar

28 LIST OF ILLUSTRATIONS

FIG. PAGE

32. DIATOM, TBICEBATIUM FAVUS, VAB. SEPTANGULATUM 108

33. SECTION OF WHEAT-STEM . . . 110

34. SECTION OF WHEAT-STEM THROUGH THE NODE . 113

35. DODDER ON CLOVER . . . .118

36. STING OF NETTLE ..... 123

37. STEM SECTION ARISTOLOCHIA GIGAS . . 128

38. STEM SECTION EATTAN CANE (CALAMUS ROTANG) 131

39. SECTION OF LILY BUD .... 133

40. SECTION OF STEM OF EXOGEN (CLEMATIS VITALBA) 135

41. TRANSVERSE SECTION OF PLANT STEM (NUPHAB

LUTEA) ..... 138

42. SPRUCE FIR, STEM SECTION . . . 140

43. SECTION OF STEM OF BUTCHEBS' BBOOM . 142

44. STEM OF SECTION OF MABE'S TAIL (HIPPUBIS

VULGARIS) ..... 145

45. VEBTICAL SECTION OF HUMAN SCALP . . 147

46. TEANSVEBSE SECTION OF HUMAN SCALP . . 149

47. HUMAN SKIN, VEBTICAL SECTION . . 156

48. HEABT MUSCLE ..... 158

49. TBANSVEBSE SECTION OF HUMAN BONE . 160

50. SECTION OF HUMAN LUNG .... 163

51. HUMAN BLOOD ..... 165

52. HUMAN TOOTH, VEBTICAL SECTION . . 167

53. KITTEN'S JAW, VEBTICAL SECTION . . 170

54. PARASITE OF LIZARD (!XODES OF IGUANA) . 172

55. HJSMATOPINUS OF BUFFALO . . . 174

56. SHEEP TICK . . . . . .177

57. PARASITE OF BEE (BRAULA C-ECA) . . 178

58. CHEESE MITE . . . . 180

59. MlDEOPSIS ORBICULARIS . . . 181

60. SPIDER'S FOOT AND PART OF LEG. . . 183

61. WOLF SPIDER . . . . 184

62. TETANUS (LOCKJAW) BACILLI . .' . 187

63. SCALES ON SKIN OF A SOLE . * * 190

64. CIBCLET OF HOOKS ON A ScoLEX . . .193

65. FINE SILK . . V ' . . 194

CHAPTER I

THE ILLUSTRATIONS AND HIGH
POSSIBILITIES WITH THE MICROSCOPE

The Illustrations.

rnHE illustrations have been taken from
-*- photo-micrographs done on 12 by 10
plates directly through the microscope and
camera combined as one instrument. The
negatives have received no ' touching-up '
whatever.

They were exhibited at the Royal Society's
Annual Conversazione, May 13, 1904. In the
catalogue is the following summary of the
exhibit : —

' Examples of Photo-Micrography. The ex-
hibit includes sections of histological, botanical,
and entomological specimens, intended to assist

30 THE ILLUSTRATIONS

students of biology generally and medical
students especially. The camera used is un-
usually large in order to ensure direct photo-
graphy. In no case are the results produced
from the enlargement of small negatives.7

Subsequently we were invited to exhibit
them at the Conversazione of the London
University held at the Imperial Institute,
May 27.

When photographs are enlarged from small
negatives there is no material gain as regards
new details. The advantage of a large camera
(Fig. 3) is shown in several of the illustrations
where a vast amount of design is visible which
could not be secured by ordinary enlargements.

We are well aware that with the electric
light or even the oxy-hydrogen lime-light,
time could be saved as regards the exposures;
but for general workers it is better to show
what can be done with ordinary means of
illumination, than to lead them to think that
the electric or other light is indispensable.

The extra large camera is not absolutely
necessary in all cases of photo-micrography,

RE-TOUCHING UNNECESSARY 31

but for certain diatoms and other objects that
display excessively minute structure it has its
advantages, some of which, we hope, are
apparent in the illustrations.

Excellent results have been obtained by
primitive or homely methods and appliances.
In fact two or three boxes telescopically ar-
ranged will answer all the ordinary purposes
of an elaborate camera fitted with long
bellows.

In photographing the features of the human
being it is customary to submit the negatives
to a system of re-touching. The photographers
would do very little of this were it not for
the vanity of their customers, and they would
do very little photography if they were to
omit the re-touching process.

But as regards the photography of micro-
scopic objects it is a mistake to add any line
or to make any object look as we would wish
it to look. Drawings from microscopic objects
often betray this defect.

No artists7 license should be resorted to
beyond reducing the density of, or strengthen-

32 NATURE IS PERFECT

ing the negative. The personal equation must
be left out, for it is hardly likely that any
naturalist can suggest an improvement in the
design of a diatom, of a radiolarian, or of a
section of an ordinary plant. Laplace, the
famous French astronomer, and undoubtedly
one of the greatest astronomers of any nation,
thought he could suggest a much better
position in the heavens for the Moon (see
Richard Proctor's The Expanse of Heaven,
chap. ii.). Similarly, to judge by the inter-
pretation put by some on the structure of
minute forms of life, daring, if not conceit,
manifests itself in a surprising degree.

Shakespeare teaches us all a lesson on this
point : —

'To gild refined gold, to paint the lily,
To throw a perfume on the violet,
To smooth the ice or add another hue
Unto the rainbow, or with taper-light
To seek the beauteous eye of heaven to garnish,
Is wasteful and ridiculous excess.'

to face page 32.

FIG. 6.
DIATOM, ACTINOCYCLUS RALFSII.

X750.

\_see page no.

THE HIGHEST MAGNIFICATION 33

High Possibilities with the Microscope.

What is the highest magnification obtained
with the modern microscope ?

This is a question the microscopist is fre-
quently asked.

Two answers can be given to that question.

Those unacquainted with the use of the
microscope will bear in mind that students of
that instrument never speak of the superficial
area of any microscopic amplification ; it being
understood by them that dimensions are
always to be expressed in diameters only.

Those who, at the Eoyal Society's recent
Conversazione, were privileged to see the "High
Power Microscopy," by Mr. J. W. Gordon, must
have realised that microscopy had made a
decided step forward by that gentleman's in-
vention.

The answer, or one of the answers to the
above question, will be apparent from a brief
consideration of Mr. Gordon's ingenious
methods.

He had two microscopes. In the field of

3

34 MICROSCOPIC POWERS

view of one he placed an opalescent screen
which he kept oscillating to serve as a
secondary source of radiation and to expand
the transmitted wave front, causing it to fill
the aperture of the second microscope. This
latter instrument gave a further magnification
of 100 diameters. The oscillation of the ground
glass or opalescent screen removed the imper-
fections of excessive magnification and rendered
invisible its own grain. A diatom (Pleurosigma
angulatum) was exhibited, and showed an
amplification of 10,000 diameters. Its mark-
ings were clearly defined.

When we remember that this particular
diatom is practically invisible to unassisted
eyesight, and that its highest amplification
in Dr. Dallinger's edition of Carpenter's
Microscope and its Revelations is 4,300
diameters, we cannot but realise that a
very distinct advance has been made.

To suggest a second answer to the question
propounded, I must refer to diffraction grat-
ings or microscopic rulings.

Lines have been ruled by extremely

SPECULUM METAL RULINGS 35

cate instruments on speculum metal up to
14,000 lines, and even more, per inch, but so
far Mr. Grayson has far surpassed all other
records in microscopic rulings. His plates
contain 120,000 lines per inch.

Mr. E. M. Nelson, one of the greatest
authorities on microscopic research, tells us
his experience in resolving those lines ; it
need hardly be said that such fine work
requires uncommonly good microscopic powers
and excellent illumination for their resolution.

Mr. Nelson found that he could resolve
strongly the 120,000th band with a £th inch
oil immersion lens ; he also resolved the same
lines with a cheap -f^ih inch oil immersion.

The 90,000th band he resolved with the |th
inch, and also with a Powell and Lealand's
best | inch ; and the 60,000th band with a
Zeiss J inch. (Royal Micros. Journal, 1904).

The rulings are mounted in realgar, and are
more difficult to resolve than diatoms of equal
fineness.

This being Mr. E. M. Nelson's experience,
the statement made in the latest works on

36 MICROSCOPIC POWERS

optics used in the Universities that f the
theoretical limit of microscopical vision is the
TOWU^h °f an inch' is hardly correct, inas-
much as 120,000 lines, or Jrd more, can
actually (not theoretically) be seen showing
up strongly with a Jth inch oil immersion,
which is by no means a very high-power
objective nowadays.

Although the high amplification of 1,000
diameters is not an extensive limit to the
powers of the microscope, yet, beyond this, the
objectives must be higher than the T^th inch,
and the eye-pieces of the highest power.

Only a few, who may be looked upon as
specialists in microscopy, ever exceed this range
of magnification.

Several of these illustrations are from nega-
tives of much higher amplification than 1,000
diameters, but in these cases the camera has
augmented the work of the microscope.

CHAPTER II

PRACTICAL HINTS ON PHOTO-
MICROGRAPHY *

A MICROSCOPE slide for photographic
•*"*- purposes should be perfect and the
object typical. An imperfect slide is difficult
to photograph and never looks well.

The starting point is to place the slide in
the microscope and see exactly what is required
to be photographed ; the microscope can then
be placed horizontally and the lighting arranged
so that the effect seen when viewed through
the tube is exactly what is required to appear
in the photograph. (Fig. 7).

It is well and convenient to have the camera
and microscope adapted to a rigid and per-
fectly straight base and in such a manner
* This chapter is contributed by Arthur E. Smith.

37

3* PHOTO-MICROGRAPHY

that the camera may be easily lengthened or
shortened.

If the camera can be placed on runners or
in a sliding groove to allow of its being moved
aside while the object is being illuminated
and adjusted in the microscope it will be a
decided advantage.

This done, the front of the camera should
be brought up to the eye-piece end of the
microscope. The point of junction must be
made light-tight, and the whole fixed so that
the two instruments are, for the time being,
practically one.

There will now be some sort of an image
on the ground glass, and a slight adjustment
of the focus ought to make that image sharp.

A long rod or a cord can be placed along
the length of the camera and adapted to work
the adjustment-screw of the microscope in either
direction, as shown in the illustration (Fig. 8).

For the low and medium powers a
focussing glass can be used with great advan-
tage, but with very high powers when the
image is dim the focussing can be better

THE MICROMETER 39

done with the naked eye or with a very low-
power magnifier.

The magnification should be carefully ascer-
tained and marked on each negative. For
lower powers this is easily found by using a
thin piece of metal with, say, a Jth inch hole
bored through it. When the photograph is
taken and the microscope slide removed, the
piece of metal is placed on the stage of the
microscope. The image of the hole falls on
the ground glass screen, and its amplification
can be easily ascertained.

With high powers a micrometer must be
used. This is a glass slide with lines ruled
on it, the y^th and y^th of an inch apart.
This is focussed as in the former instance on
the ground glass screen. If the lines of the
T^th divisions appear 2 inches apart, then
its magnification is 200 diameters. If the
lines of the •nnny*'1 division appear, say, 3 inches
apart, the magnification will be 3,000 diameters.

A convenient method is to have the support
of the camera graduated in inches and parts
of an inch. In this way the amplification

40 PHOTO-MICROGRAPHY

would be known without measuring each
time.

The focussing cloth may be used in the
usual way for low powers, but is almost out
of the question for high powers. With very
high powers the best way is to have a special
perfectly dark room for the camera.

The Developer, Plates, &c.

A convenient developer is that originally
issued as the Ilford Universal Developer, but
somewhat modified for ease of mixing.

Very weak images to low magnifications can
advantageously be produced on process plates,
as these give great contrast.

The higher magnifications must be done on
quick plates.

The exposures vary from two seconds to
about two hours, or even longer. These long
exposures of the higher powers are very difficult
to keep free from vibration. The slightest
shake, as a matter of course, spoils the
negative. A good condenser will materially
shorten the exposure.

USE OF SCREENS 41

Isochromatic plates are generally most useful,
as with the object stained purple, which is
usually the case, a yellow screen has to be
used between the light and the object to
make the purple come out much stronger.
At the same time it increases the exposure
four to six times, according to the density
of the yellow glass screen. The yellow screen
can also be used to reduce contrast where part
of the image is yellow. Take as an example,
a transparent insect containing yellow eggs ;
in the ordinary way of photographing, the
eggs would come out dark, but with a yellow
screen the eggs would come out full of detail.

The illustrations have been, for the most
part, taken on 12 by 10 plates. For this size
a comparatively long camera had to be used.

The objectives can be used without any eye-
pieces, or with varying eye-pieces, according to
the magnification required.

Approximate Exposures.

If an object has a normal exposure, say, of
10 seconds when amplified to 20 diameters,

42 AMPLIFICATION

it will require an exposure of 1,000 seconds
(just over 16 minutes), if the amplification is
to be 200 diameters.

Thus 200 = 10
20

102 = 100

100 x 10 sees. = 1,000 sees.

= 16 mins. +

If the exposure of an object be lj- mins.
when the amplification is 45 diameters, the
exposure will be 13J mins. if the amplification
is to be 135 diameters.

452 : 1352: : Ij mins. to 13J mins.

The magnification can be calculated approxi-
mately when no eye-piece is used, thus : —

With a 1-inch objective and a 40 inches
focus the magnification should be 40 diameters.

Or, with a ^th objective and a 30 inches
focus the magnification should be 30 x 6 = 180
diameters.

But as the objectives are not always

OBJECTIVES 43

accurately marked this method is not always
reliable.

The photographs from which these illustra-
tions have been taken have been done with
achromatic objectives.

In no case has any touching-up been
resorted to.

CHAPTER III

FOSSIL RADIOLARIA (POLYCYSTINA)
AND FORAMINIFERA

Fossil Radiolaria.

(Polycystina.)

~T~N the opinion of a great many microscopists
•*- there is no more beautiful object for study
than a slide of polycystina from the rocks of
Barbados.

People have been tempted to purchase micro-
scopes from having seen, for the first time, a
collection of these matchless structures. Word-
painting fails to describe their attractiveness.
Photography through the microscope helps to
convey a something of their beauty, but the
actual specimens must be seen mounted on a

FIG. 9.
POLYCYSTIXA FROM BARBADOS.

xi75-

{to face page 44.

OCEAN SURFACE DREDGINGS 45

dark background in order to arouse the enthu-
siasm they deserve.

To know something of their history and
nature we must consider some of the details
of structure of living representatives of these
homes or skeletons of creatures of long-past
ages.

During the ' Challenger ' expedition vast
numbers of exquisite forms assumed by the
skeletons of the Eadiolaria were found in the
ocean surface dredgings. Some of them consist
only of spines radiating from the centre, which,
however, are often beautifully sculptured and
branched. In one particular form the number
of spines is always twenty, and these are all
arranged with absolute regularity at definite
angles to each other. All this mathematical
accuracy in a flinty framework about the
hundredth of an inch in diameter !

Some of the creatures appear as spiny balls,
one ball inside the other, and fitted together
by lattice works of flint of glassy texture.
Ball within ball, they remind one of the
Chinese carvings in ivory.

46 FOSSIL RADIOLARIA

The protoplasm, or soft body of the tiny
organism, surrounds the framework inside and
outside. Some of the skeletons take the form
of a network with hexagonal apertures.

A framework may be round for a time, and
then a second framework may be added below
the first with a wide opening at its base, the
whole having the outlines of a helmet orna-
mented at definite points. There is an extra-
ordinary variety of form in the skeletons of
Eadiolaria. In all cases the fossil forms, as
well as their existing representatives, are of
microscopic dimensions, and, taken individually,
they are scarcely, if at all, visible to unaided
sight.

Eadiolaria are all marine ; most of them live
near the surface in tropical seas, and their
skeletons sink to the bottom of the ocean,
where they are now forming extensive deposits
of radiolarian ooze at depths of from 2,000 to
4,000 fathoms.

Passing now to the fossil forms, the flinty
skeletons seem to retain most of their beauty,
even though embedded for untold centuries in

GEOLOGICAL AGE 47

the siliceous marls and shales of the Tertiary
age which occur in Barbados, Cuba, Trinidad,
Kichmond in Virginia, Sicily, and the Nicobar
Islands.

The Eadiolaria in these deposits retain the
glassy silica of their shells, and for the most
part they are in as perfect condition as recent
forms, and many are of the same species as
those now living.

Recent researches in geology show that
Radiolaria may be of great geological age, and
that they occur in siliceous rocks of all forma-
tions from the Cambrian upwards.

There need be no difficulty in obtaining
specimens for examination, as will be seen
from a subjoined list of rocks in which they
are to be found in abundance.

Localities and rocks in which Eadiolaria have recently
been found: —

Cambrian strata in Thuringia.

Reddish rocks of Ordovician age in the South of Scotland.

Shales in Languedoc and Saxony.

Jaspers of Devonian age in Siberia.

Kieselshiefer of Hesse and Nassau.

Lower Culm or Carboniferous strata of Devon and
Cornwall,

48 FOSSIL RADIOLARIA

Jaspers and Whetstones in the Hartz and the Ural
Mountains.

Triassic rocks of Hungary.

Liassic rocks of Hanover and the Tyrol.

Jurassic rocks of Italy and Hungary.

Coast ranges of South California.

Cretaceous rocks of Westphalia and Manitoba.

From this extensive list it will be seen that
the Kadiolaria, with all their beauty of form,
are as old as most forms of life, and that their
history runs parallel with that of most of the
massive land and marine creatures of several
successive geological epochs.

They form the chief constituent in the com-
position of the jasper, chert, and hornstone
of vast extent in the Mesozoic and Palaeozoic
rocks. In fact these rocks, however intensely
hard they may appear, are mainly formed of
Kadiolarian skeletons. By making thin micro-
scopic sections these organisms may be seen
distinctly.

Greater satisfaction will, however, be secured
by submitting a sample of Barbadian rock to
the following process : —

< Crush the rock and boil it in a strong solu-

METHOD OF MOUNTING 49

tion of common washing soda until separated
into tiny particles. Strain off and keep back
the sediment, the object being to get rid of
any trace of carbonate of lime and to keep
the tiny polycystina shells. These must be
washed several times and then put into a test-
tube with nitric acid and boiled for half an
hour to remove any possible appearance of lime.
Again they must be removed and repeatedly
washed in water to get rid of the nitric acid.
They are then ready for mounting, and should
be bottled in distilled water until required.'
This is Mr. Martin J. Cole's method of mount-
ing them, and it cannot be excelled.

When a number of these fossil forms
are placed under the microscope, they will
be found to be a thing of beauty and a joy
for ever.

It is no exaggeration to say that sermons
have been preached which have been prompted
or suggested by a microscopic view of these
matchless and exquisitely beautiful organisms —
part of Nature's building material. And why
not ? Nature is the ' other book,' and the more

4

50 FOSSIL RADIOLARIA

both books are thoroughly understood, the more
they will be found to harmonise.

I recommend the polycystina to all grades
of thinkers, to scholars of every school of re-
search, to divines, to philosophers, to teachers
of youth, to leaders of thought, with the full
confidence that the study of these almost in-
visible relics of life will impress their minds
with the grandeur of Nature, the marvels of
geology, the possibilities and the potentialities
of mere specks of flint. And their influence
is not likely to end even there.

With regard to the first illustration of
Polycystina (Fig. 1, frontispiece), the original
photo-micrograph had an amplitude of 40
diameters. The exposure was three minutes
in sunshine. The second illustration (Fig. 9)
is from a photograph of 175 diameters. It was
also produced in sunshine, with an exposure
of eight minutes.

Foraminifera.

Under the microscope these shells, whether
recent or fossil, are always objects of great

FORAMINIFERA 51

admiration. Even if they were as large as
they are represented in the illustration they
would be looked upon as attractive, but we
have to try and realise that many of the
Foraminifera are no bigger than a pin's head,
while many are very much smaller. Beauty
where there seems to be no space for its
display must always impress us all the
more.

In nature the shells of this family play so
gigantic a part that the mind seems unable
to grasp an idea of the enormous range they
cover in the earth's crust, to say nothing of
their numerical strength or the amount of
individual life they represent.

They form an Order in the Animal King-
dom belonging to the sub-kingdom Protozoa
and to the class Ehizopoda.

Most of the foraminifera are microscopic,
and their beauty is seen only under the
microscope. The tiny animals themselves are
marine, gelatinous, and almost structureless,
but their shells are composed of carbonate of
lime for the most part.

52 FORAMINIFERA

Their shells range from the simple single
cell or chamber to compound or multilocular
aggregations of considerable complexity and
great attractiveness of form.

In some instances the cells are arranged
end to end in a straight line ; in others the
row of cells is arranged spirally.

In some instances two rows of cells are
arranged in alternate spirals. Some have the
cells opposing each other around an imaginary
axis. There are discoidal shells of intricate
and complicated forms, such as the Orbitolites.
There are others that in their early days
are arranged spirally like small ammonites,
but which, when fully grown, have their
shells produced at a tangent, so that they
look like so many old-fashioned pistols in
miniature.

The surfaces of these tiny shells show
numerous openings or foraminae (hence the
name), which are the outer orifices of
tubules passing through the walls of the
shells.

Most of the buildings in Paris are con-

FIG. IO.

FORAMINIFERA.
X 2O.

\to face Page 52.

NUMMULITIC LIMESTONE 53

structed of a limestone that is composed
chiefly of foraminifera shells known as
Miliolida.

The rocks comprising the Pyramids of
Egypt are almost entirely nummulitic, that
is, coin-shaped foraminifera.

If the foraminifera supplied no more mate-
rial than that required for the construction
of these Pyramids they would be considered
extensive as products of animal life, but the
Pyramids are only a very small portion of
the shelly deposit of an ocean floor of earlier
ages, now considered as belonging to the
Tertiary formation, which extends along the
south of Europe and northern Africa into
Asia.

The nummulitic limestone alone, which repre-
sents only one series of the foraminifera beds,
attains to a thickness of several thousand feet
and contributes largely to the formation of
the Pyrenees, Alps, Apennines, Carpathians,
and Himalayas.

The mind is overwhelmed when one tries
to think either of the life represented by

54 FORAMINIFERA

the foraminifera of the past, or the time
required for the deposition of such vast
hosts of shells in the formation of limestone
rocks.

The creatures have left behind the most
gigantic results ; results, too, that are on the
side of the elevating operations of Nature as
opposed to the degrading or wearing-down
influences, such as the action of water,
oxygen, or carbonic acid, &c.

Other members of the foraminifera, known
as fusulina and rotalia, took a large share in
building up the limestones of the Old World.

Notwithstanding the minuteness of these
shells, most of them are partitioned into
several chambers, even if sufficiently small to
drop through the eye of a needle.

Plancus counted 6,000 shells in an ounce of
sand from the Adriatic. Omitting the sand
and weighing the shells only, 280,000 would
be required to weigh a single ounce.

One of the best examples of a strand com-
posed almost entirely of foraminiferal shells
in the British Islands is that of Dog's Bay on

LOCALITIES WHERE FOUND 55

the west coast of Ireland. The light shells are
blown inland in myriads for a considerable
distance, forming drifts and mounds. From
this bay alone Chapman obtained 124 species
and varieties.

The shells of the foraminifera are easily
distinguished by their peculiar shape and
texture. They are sometimes white and
opaque, glassy or translucent, and often deco-
rated with the finest and most beautiful
tracery.

Almost any sheltered bay will supply many
varieties for examination. Even a piece of
seaweed taken at low tide and placed in a
glass vessel of fresh water will be found to
contain a good number alive, as they leave the
plant for the sides of the vessel.

The shallow-water sands of the Grecian
Archipelago and the Levant contain large
proportions of foraminifera shells. Any new
sponge from these localities will be found to
contain quantities, which may be secured by
shaking the sponge over a paper or over a
vessel of water.

56 FORAMINIFERA

By carefully washing a specimen of chalk
from the top layer in a chalk cliff many
varieties may be obtained. The clays also
of the Lias and Oolite contain many exquisite
representatives of the foraminifera.

The original photograph from which the
illustration (Fig. 10) was taken is 40 times
the diameter of the tiny fossil marine
shells represented. A 2-inch objective was
used ; the focal distance was 84 inches ;
and the time of exposure was 15
minutes.

FIG. II.
RADULA OF WHELK.

><75-

[to face Page 56.

FIG. 12.
RADULA OF WHELK.

x6o.

face page 57.

CHAPTER IV

CIRRI OF BARNACLE AND
SPINES OF ECHINI

Radulae.

A T all times the ' tongues ' of the gaster-
-£*• opoda form very attractive objects for
microscopic observation, inasmuch as they dis-
play a marvellous arrangement of elegant horny
or chitinous teeth. The teeth are arranged in
patterns and rows with mathematical precision.
By their number, position, and arrangement
as well as by their individual shapes they are
of importance in characterising the families,
genera, &c.

The c tongue ' in every instance greatly assists
the creature either as a rasp for grinding sea-
weed, or as a hole-borer when used for drilling

57

58 RADUL/E

holes in the shells of other creatures for what
may be termed sarcophagous purposes. This
remarkable organ has a variety of names, and is
known as a radula, a spiny tongue, an odonto-
phore, a lingual ribbon, lingual band, &c.
In any case the word ' tongue ' is hardly so
appropriate as ' radula ' or ' odontophore.' In
the Gasteropods this apparatus, together with
the jaws, completes a marvellous mouth-
armature admirably adapted for the rasping
or trituration of their food before it reaches
the oesophagus and stomach.

The bivalves are not provided with radulae.

With regard to the structure of the radula,
in general terms it may be said to consist of a
cartilaginous strap which carries a long series
of transversely disposed teeth. By means of a
perfect arrangement of muscles and cushions
the strap works backwards and forwards as
though over a pulley, after the manner of a
chain-saw. When the food has passed beyond
the operation of the jaws it comes within the
province of the radula to tear or scratch, not to
bite it. The food passes over it and is carded

HOW USED 59

small, the effect being, as a writer describes it,
very much the same as if l instead of dragging
a harrow over the surface of a field, we were to
turn the harrow points upwards and .then drag
the field over the harrow ' ! *

The resulting wear and tear of the anterior
teeth is continually made good by the incessant
development of new teeth formed in a sort of sac
in which the hinder end of the strap is lodged.

In addition to this chain-saw-like motion the
odontophore has a scraping action, more or less
in a circular direction, whereby the shells of
other creatures are gradually bored.

If the radula of a limpet or whelk freshly
extracted be drawn across the hand, the teeth
can be plainly felt.

Now as to the disposition of the teeth on the
radula. The arrangement as well as the number
of teeth vary in the different representatives of
the Gasteropoda. The teeth are almost invariably
disposed in a kind of pattern like the longi-
tudinal rows of colour in a piece of ribbon (for
the teeth are beautifully coloured, even apart
* Cambridge Natural History.

60 RADUUE

from a polariscopic view), down the centre of
which runs a narrow stripe, and every band of
colour on one side is repeated in the same
relative position on the other side. The middle
teeth are known as the ' rachidian,' the teeth
next adjacent on each side are known as
1 laterals/ while the outermost are styled
' uncini ' or ' marginals.'

In the radula of the common whelk (Buc-
cinum undatum) there are about two hundred
and fifty teeth. In that of the common peri-
winkle about three thousand five hundred. In
the Ear Shell (Haliotis tuberculatus) the odonto-
phore is well developed. The teeth on the
median line are flattened out, recurved and
obtuse, those on the inner or first rows of
laterals are trapezoidal, while those known as
the ' uncini ' are generally hooked. The odon-
tophore of this creature seems to be most
complicated, the teeth vary in shape so much.
In fact, those of the inner laterals may be
compared to those of the shark, but are ex-
tremely minute. Instead of one row each, the
outer laterals contain several rows of teeth.

FIG. 13.

RADULA OK LIMPET.
X IOO.

[ to face page 61

ODONTOPHORES OF WHELKS 61

This creature's lingual band is divided
into five different areas, distinguishable by
the different characters of the teeth they
bear.

The odontophore of the common whelk has
only three plates in each row, one carrying the
small central teeth and the two lateral ones
bearing the larger teeth. It is one of the most
fascinating for observational purposes.

In the illustrations the odontophores of two
different whelks are shown, and it will be
noticed that there is a difference between them,
a difference that in the actual specimen could
not be detected but by the microscope. In
the central area of Fig. 11 there are six tiny
teeth in each horizontal row, but in Fig. 12
there are seven. Whether an abnormal con-
dition is here presented to us, or whether the
extra tooth per row in the median area is a
question of the creatures7 comparative ages, we
must leave to the opinion of the marine
biologists.

The radula of the English limpet (Patella
vulgata) is longer than the shell itself, and is

62 RADULJE

provided with 1,920 glassy hooks in 160 rows of
12 teeth each.

But it is among the land representatives
of the Gasteropoda that we meet with the
most astonishing instances of large numbers of
teeth.

Helix Pomatia has 21,000 arranged in sym-
metrical order on its lingual band. The large
garden slug (Limax maximus) possesses 26,000.
A single tooth measures only the 10,000th of
an inch ! These numbers, again, are excelled
by the Umbrella mediterranea and the Um-
brella indica. They seem to baffle calculation.
Possibly 750,000 may be somewhere near the
truth.

In the illustrations shown, only small portions
of radulse are taken and amplified to about 100
diameters. Even these show that the number
of teeth on each must be very great indeed.
When it is remembered that the foregoing
numbers refer to a series of forms curiously
carved and sculptured, and the total area
carrying them in magnificent regularity is only
like that of a coiled-up wateh-spring, we must

AMPLIFICATIONS 63

be filled with admiration at the marvellous
creative power lavished upon the organisation
of these lowly creatures.

The illustration of the whelk's radula (Fig. 11)
is from a negative of 100 diameters ; the objec-
tive used was the half-inch and the focal length
50 inches.

That represented in Fig. 12 is from a negative
of 80 diameters ; the objective was the half -inch
and the focal distance was 40 inches.

The radula of the limpet (Fig. 13) is illus-
trated from a photo-micrograph representing
the object amplified to 100 diameters; the
objective used was the half -inch and the focal
distance was 50 inches.

The Cirri of Barnacle.

The word * cirri ' is from cirrus, * a lock of
hair.'

Both the chief representatives of the Order
Cirripedia, viz., the Lepas or Barnacles, and
the Balani or Acorn-shells, possess several
pairs, generally six, of the appendages as
shown in the illustration.

64 CIRRI OF BARNACLE

The stones and pillars near the jetties at
the seaside are often to be found covered
with acorn-shells. If a stone so encrusted be
placed in a glass vessel of clear sea-water, the
delicate plumes may be seen opening out and
then retracting. The protruding and retracting
processes are accomplished with regularity and
order. These form the creature's fishing-
tackle. They are prehensile and flexible, and
consequently are admirably adapted to catch
any nutritious particles within their reach.

The sense of touch is exceedingly keen in
all parts of these wonderful casting-nets. By
the constant movements which the cirri keep
up, currents are formed which bring food-
particles within their grasp and on to the
mouth. The barnacles in the adult stage fix
themselves by a fleshy stalk to any suitable
object — shells, drift-wood, ships, &c. — and
develop a peculiar multivalve shell. The
acorn-shells attach themselves directly, with-
out any stalk, to stone or wood.

Sometimes after a long voyage the bottoms
of ships have to be freed from the barnacles.

Fit;. 14.

CIRRI OF BARNACLK.

x 1 8.

\_to face page 65.

FLOATING TIMBER 65

Several tons have been removed from one
ship.

Vast quantities of floating timber that
would, under ordinary conditions, seriously
interfere with marine commerce is rendered
heavier by barnacles and other creatures, and
sinks to lower depths. This department of
marine life has been more fully dealt with
in Nature — Curious and Beautiful.

The illustration (Fig. 14) is from a dark-
ground photo-micrograph, showing the object
as if amplified to 36 diameters. The time of
exposure was 15 minutes; the objective used
was the 1J inch, and the focal distance was
52 inches.

Spines of Echini.

To appreciate the complex structure and
the beauty of the spine or spike of a sea-
urchin, it will be necessary to give a little
attention to the plates which make up the
shell or ' test,' and also to the tubercles.
The shell consists of a number of plates

5

66 SPINES OF ECHINI

fitted together with greater precision than the
various parts which make up a coat of mail.
The shell adapts itself in the matter of
growth to the creature it contains. It is a
marvellously strong structure when we con-
sider how very light it is.

Its beauty may be seen by removing all the
spines. Sailors, who, generally speaking, have
plenty of time on their hands, are adepts at
polishing these natural boxes. The work re-
quires great gentleness of handling, but when
well done amply rewards the polisher.
Previous to the polishing process, but with
the spines removed, the surface of the plates
will be seen to be covered over with tubercles.
Each tubercle consists of a rounded boss, on
the centre of which is a small pimple or
mamelon.

'These tubercles are of three different sizes,
primary, secondary, and miliary. The primary
are the largest, and bear the largest spines.
Scattered irregularly over the plates are the
secondary tubercles, which carry the secondary
spines, and between these are numbers of

STRUCTURE OF SPINES 67

smaller elevations, the miliary granules. In
addition to the spines, the pedicillariae are
also supported on the top of these tubercles.
The spines, like the tubercles, are of three
sizes, primary, secondary, and tertiary, and
the structure of each is fundamentally the
same. Each spine consists of a long shaft
marked by longitudinal flutings ; the base is
hollowed into a cup or condyle, which fits
over the pimple of the tubercle. Each spine
is furnished with a collar which serves for
the attachment of the muscles which fix it
to the test.1 (A Treatise on Zoology.)

The transverse section, as in the illustra-
tion, shows that the spine is made up of a
number of solid wedges radiating from a
central axis, and separated by bands of porous
tissue.

The sections vary in design in the spines
of different kinds of sea-urchins. Thin
sections of spines make very beautiful objects
for the microscope. Patterns for rose
windows, for lace, and other forms of orna-
mental handiwork may be obtained from these

68 SPINES OF ECHINI

lovely forms of marine life. The photo-
micrograph from which the illustration
(Fig. 15) was taken shows an amplification
of 80 diameters. The time of exposure to
gas-light was 10 minutes ; the focal distance
was 80 inches, and the objective was the
one inch.

FIG. IS-
ECHINUS SPINE SECTION.

x6o.

[to face page 68.

CHAPTEE V

INSECT LIFE : PROBOSCIS OF BLOW-
FLY AND EGGS OF FLY

Insect Life.

A T first sight the study of insect life may
•*"*' not appear very attractive, but there
are some insects far more gorgeous in their
every-day coats than are many of the Eastern
potentates when bedecked with jewels of un-
told costliness. The microscope brings the
insect's gems and scales and facets and
plumes within the bounds of our appreciation,
but fails to exhaust all their sheen and un-
sullied brightness.

The various parts of the insect command
our highest admiration. The muscular system
of insects has always excited the wonder and

70 INSECT LIFE

astonishment of the naturalist from whatever
point of view he has examined this part of
their economy — whether he considered the
perfection of their movements, the wonder-
ful minuteness of the parts moved, or the
strength, persistence, or velocity of their con-
tractions.

It is true that some insects do a great
deal of damage, but there are others that
confer additional life, gaiety, and beauty to
the landscape. But is it not a wonderful
law of Nature that restricts the dimensions
of an insect within certain bounds ? The
ravages committed by them now are trifling
and insignificant in comparison with what
they could do if they were allowed to attain
to a large growth, and still possessed the
extraordinary powers with which they are so
conspicuously gifted. They could exterminate
all that the earth contains of vegetable and
animal life !

Kymer Jones tells us that the dragon-fly
possesses such indomitable strength of wing
that for a day together it will sustain itself

/

FIG. l6.

PROBOSCIS OF BLOW-FLY.
X40.

{to face page 71.

THE HOUSE-FLY 71

in the air, and fly with equal facility and
swiftness backwards or forwards, to the right
or to the left, without turning. The same
writer asks us to suppose for a moment that
the law which restricts the dimensions of an
insect could be dispensed with in a single
species. Suppose a wasp or a stag-beetle
dilated to the bulk of a tiger or of an
elephant — cased in impenetrable armour, fur-
nished with jaws that would crush the solid
trunk of an oak — winged and capable of flight
so rapid as to render escape hopeless — what
could resist such destroyers? Or how would
the world support their ravages ? With
regard to the house-fly (Musca domestica),
Bymer Jones quotes an anonymous writer
who has calculated the flight of this insect :
' In ordinary flight it makes with its wings
about 600 strokes, which carry it 5 feet, every
second; but if alarmed their velocity can be
increased six or sevenfold, or to 30 or 35 feet
in the same period! In this space of time an
Arab steed would clear only 90 feet, which is
at the rate of more than a mile a minute.

72 PROBOSCIS OF BLOW-FLY

Our little fly, in her swiftest flight, will in
the same space of time go more than the
third of a mile. Now, compare the difference
of the size of the two animals (ten millions
of the fly would hardly counterpoise one
racer), and how wonderful will the velocity
of this minute creature appear! Did the fly
equal the racehorse in size, and retain its
present powers in the ratio of its magnitude,
it would traverse the globe with the rapidity
of lightning/

Proboscis of Blow-fly.

Perhaps no object in insect life has been
photographed more frequently, yet it may be
said with truthfulness that no microscopist has
ever succeeded in either exhausting or in depict-
ing all its detail. The proboscis of the blow-fly
or that of the house-fly defies the highest am-
plification and still reserves to itself man}7
mysteries never seen by the microscopist. It
is more complicated than a locomotive, and
more highly finished than a costly gold watch.

BEAUTY OF STRUCTURE 73

It is a contrivance that commands our ad-
miration although we are acquainted with but
a few of its actions and uses.

Its exquisite beauty, the minuteness of its
thousands of springs, and the finish of its
mechanism have led many a man to reflect on
his own impotence, and have suggested to his
mind something of the sublime skill that must
be behind all that we are pleased to call
1 Nature.'

The specimen, photographed for the accom-
panying illustrations, in order to show its histo-
logical structure, has been opened out and its
lobes spread apart so as to present a thin section
for microscopic examination.

Only a portion of the proboscis is shown in
either instance. The maxillary palpi and most
of the muscular parts are purposely omitted.

A symmetrical system of canals pervades
each lobe. These are made up of spring-like
structures arranged side by side, which at first
remind one of the tracheal system of the water-
beetle Dytiscus ; but on closer examination they
are seen to be not spirally arranged, but forming

74 PROBOSCIS OF BLOW-FLY

open channels, which suggest an arrangement
for the passage of fluids.

From the observations of Doctor Anthony
these ' pseudo-tracheaB ' are suctorial organs,
which can take in liquid alike at their ex-
tremities and throughout the whole length of
the fissures. These fissures may be closed in
and thus form complete tubes. This of course
implies a voluntary power on the part of the
fly which extends to microscopic areas.

The original photo-micrograph from which
the illustration (Fig. 16) was taken, shows an
amplification of 100 diameters ; the time of ex-
posure was 16 minutes ; the focal distance was 50
inches, and the objective used was the half-inch.

In the second illustration (Fig. 17), the
original amplification is 1,000 diameters; the
focal distance was 46 inches ; the eye-piece of
5 diameters and the |th objective were used.

Eggs of the Fly.

There are several genera and species of flies
that are common in our houses, either habitually

FIG. I/.

PART OF FLY'S PROBOSCIS,
x 650

[to face page 74.

EGGS OF HOUSE-FLY 75

or casually, and it is by no means easy to distin-
guish and classify them. If the difficulty be
great as regards the insects themselves, it must
be greater as regards their eggs.

It is well, therefore, to describe the two
principal representatives of the Diptera — the
Muscidae and the Anthomyiidae.

The Muscidae contains many of the most
abundant flies, including the common house-fly,
the blue-bottle or blow-fly, &c.

The common house-fly (Musca domestica)
runs through its life-history in a very short
time. It lays about 150 eggs, that are very
small, on any kind of soft, damp animal or
vegetable matter. The larvae are hatched in a
day or two and feed on the surrounding carrion
or other putrid refuse ; they are fully grown in
five or six days, and then, passing through the
pupa stage, in another week or so emerge as
perfect flies.

It is not to be wondered at that in favourable
localities they increase in a short time to such
enormous numbers.

It is thought that flies pass the winter in

76 THE HOUSE-FLY

the pupal state. The house-fly is widely
distributed over the world, and it sometimes
occurs in large numbers away from the dwell-
ings of man.

The compound faceted eyes, the proboscis
and the complicated feet of the house-fly all
form instructive and interesting objects for the
microscope. It is now generally believed that
the pads on the feet do not support the fly
when walking on the ceiling or window-pane by
performing the office of suckers, but that they
exude a viscid fluid which enables the insect to
adhere to smooth surfaces.

The bite of flies that have been feeding on
putrid substances is attended with danger. It
is well that these flies are not allowed to
increase indefinitely. They are subject to the
attacks of a white fungus, and possibly to those
of a tiny insect, the chelifer.

It is hardly necessary to say that when a
fly assumes the perfect state it never grows
any larger, so that when we see small flies
that appear like the house-fly we must not
imagine they are the young of the larger ones.

FIG. 1 8.
EGGS OF HOUSE-FLY.

X42.

[to face page 77-

THE ANTHOMYIID^E 77

Linnaeus is reported to have said that the
progeny of three blow-flies could devour the
carcass of an ox as quickly as a lion could.
This would have to be under favourable con-
ditions for the multiplication of the insects.

'The other division of the Diptera is the
Anthomyiidae. These are similar in general
appearance to the common house-fly. They
form a large family of flies, and possibly the
most unattractive of the order. The eyes of
the male fly are very large and almost touch
each other. The main vein posterior to the
middle of the wing is continued straight to the
margin, and this being only so in the case of
the Anthomyiidae it forms the chief distinguish-
ing feature. The habits of the larva are varied.
Many attack vegetables, produce disintegration
in them and thus bring about decomposition.
Market gardeners are well aware of the
destructive powers of the Anthomyiidae.'*

Flies at best are not desirable visitors in our
houses, but it is evident that they act as
scavengers on a tremendous scale by devour-
* Cambridge Natural History.

78 THE HOUSE-FLY

ing obnoxious substances which might be
productive of zymotic and other diseases. It
is also evident that if we were to keep our
homes absolutely free from all impurities we
should not be so much troubled by these
visitors. House-flies will not remain long in a
house that has nothing for them to feed on.
On referring to the illustration (Fig. 18),
some 21 or 22 eggs of the fly will be seen.
They are objects of great beauty under the
microscope. The original photo-micrograph is
one of 72 diameters ; the time of exposure was
60 minutes ; the focal distance 60 inches, and
the objective used the inch.

CHAPTER VI

BUTTERFLY'S TONGUE, EYE OF DYTIS-
CUS, TONGUE OF HONEY BEE, AND
LEG OF HONEY BEE

The Butterfly's Tongue.

E structure of the proboscis or tongue
of the butterfly is inconceivably delicate.
Throughout its whole length it consists of two
half-tubes, which are convex on the outside
surfaces and concave on the inner, so that
when the two are brought together they form
a complete tube, which is lined with a very
smooth membrane. Each half-tube is sup-
posed to be an extended maxilla. In some
butterflies the tips possess a great number of
delicate papillae or fringes.

Each maxilla is made of innumerable rings
connected and moved by a double layer of

8o THE BUTTERFLY'S TONGUE

spiral muscular fibres, that wind in opposite
directions round its walls.

When unfolded each of these long filaments
is found, under the microscope, to be fur-
nished with a row of exceedingly minute teeth
along the margins. It is the locking together
of the two rows of teeth of one half-tube to
those of the other that establishes the tubu-
lar arrangement of the proboscis. They form
a complete canal leading to the orifice of the
mouth. When not in use the proboscis is
coiled up and lodged beneath the head.

The whole apparatus seems to act on pneu-
matic principles. It is adapted in every way
to suction. It pumps up the nectareous juices
from the cups of flowers, and is of necessity
of considerable length, in order to enable the
insect to reach the recesses in which the
honeyed store is lodged.

Newport describes the action of the pro-
boscis of the butterfly as follows : t On alight-
ing on a flower, the insect makes a powerful
expiratory effort, by which the air is expelled
from the interior of the air-tubes and from

FIG. 19.

BUTTERFLY'S TONGUE.

[to face page 80.

FIG. 20.

PORTION OF BEETLE'S EYE.

\to face pagf 8 1

METHOD OF USE 81

those with which they are connected in the
head and body ; and at the moment of ap-
plying its proboscis to the food it makes an
inspiratory effort, by which the central canal
in the proboscis is dilated, and the food as-
cends it at the same instant to supply the
vacuum produced; and thus it passes into the
mouth and stomach ; the constant ascent of
the fluid being assisted by the action of the
muscles of the proboscis, which continues dur-
ing the whole time that the insect is feeding.
By this combined agency of the acts of
respiration and the muscles of the proboscis
we are enabled to understand the manner in
which the humming-bird sphynx extracts in
an instant the honey from a flower while
hovering over it, without alighting, and which
it certainly would be unable to do were the
ascent of the fluid entirely dependent upon
the action of the muscles of the organ.'

The proboscis of the butterfly when coiled
up is about the same size as the fine hair-
spring of a watch, yet it is endowed with
thousands of muscular fibres and other minute

6

82 EYE OF DYTISCUS

parts, and its action is based on what we
term pneumatic principles. It is a beautiful
object, and its study with the microscope
ought to fill one with admiration.

The illustration (Fig. 19) shows only part
of the butterfly's proboscis coiled up. It is
reduced from a photo -micrograph of 130
diameters ; the focal distance was 66 inches,
and the eye-piece of 5 diameters with the half-
inch objective was used.

Eye of Dytiscus.

Only a very small portion of the very beau-
tiful eye of Dytiscus marginalis is shown in
the illustration (Kymer Jones and other emi-
nent naturalists have called this creature
Dyticus). The number of ocelli on the eyes
of insects is remarkably great. The two eyes
of the house-fly contain 4,000 ocelli ; those
of the dragon-fly, 24,000; those in the Mor-
della beetle 25,088; the eyes of the butterfly
contain about 17,000.

The dytiscus is a true water-beetle, and is

FIG. 21.

FOOT OF WATER BEETLE, DYTISCUS MARGINALIS.
X25.

\.to face page 83.

LEGS AND WINGS OF DYTISCUS 83

remarkable inasmuch as in either its larval
or its mature condition it can exist in water.
There are reasons, however, for supposing that
these creatures are modified terrestrial in-
sects. A peculiar feature of their history is
that they thrive better in the cooler waters
of the earth. Lapland is one of the parts of
Europe richest in Dytiscidae. About 1,800
species are known. Although both larvae and
imagos are perfectly at home in the water,
they must come up to the surface to get air.

The hind pair of legs is the chief means
of locomotion. These swimming legs are de-
serving of admiration on account of their
mechanical perfection.

The wing-cases so fit the body that the
air carried down by them under the water is
held, as it were, in an air-tight compartment,
and is distributed through the spiracles to the
tracheal system. When v the dytiscus feels the
necessity for fresh air, it exposes the tip of its
body exactly at the level of the water. Eespi-
ration is effected by this means as well as by the
store of air carried down under the wing-cases.

84 EYE OF DYTISCUS

The eye of Dytiscus marginalis is always
considered a beautiful object for the micro-
scope. The face of a watch and portraits of
the late Queen have frequently been photo-
graphed through the facets or ocelli of this
beetle's eye. A small portion of the eye is
best for this purpose, because it is easier to
flatten out a tiny area than the whole cup-
shaped exterior.

Glaus sums up particulars of the creature
in the following words : ' Swimming-beetles,
with filiform ten- or eleven- jointed antennae
and broad swimming-legs beset with setae ;
the hind legs project back and are especially
adapted for swimming by the possession of a
close covering of swimming hairs.7

The illustration (Fig. 20) is taken from a
photo-micrograph of 550 diameters; the time
of exposure was 10 minutes; the focal length
was 20 inches; the objective was the ^th,
and an eye-piece of 5 diameters was used.

The illustration (Fig. 21) is from a negative
of 32 diameters.

85

Tongue of Honey Bee.

The structure of the tongue of Apis mellifica
is remarkably complex, and yet -comprised
within very small dimensions. The two outer
semi-sheaths are greatly extended maxillae,
which form a tube-sheath, when closed, for
the protection of the delicate lingula or
tongue proper, as well as the two labial
palpi. These latter are also greatly de-
veloped, and coming together form an inner
sheath for the tongue. The tongue itself, being
a most delicate organ, is well protected by
double sheaths.

When it is necessary to put the tongue
into operation the maxillae pierce the flower
and open out, enlarging the opening made to
make way for the tongue to penetrate the
flower-depths for their juices. The tongue,
when in use, is capable of protrusion far be-
yond the limits of its double sheaths. It is
a veritable proboscis covered with hairs. When
the whole apparatus is closed, the tongue is
retracted into a small space.

86 TONGUE OF HONEY BEE

It was the opinion of Dr. Jabez Hogg that
the tongue is cylindrical, and used after the
manner of that of the butterfly. But this
does not seem to be borne out in the illustra-
tion. In the original photo-micrograph we
have the whole apparatus shown 10 inches
long. Of this length the tongue proper is 5
inches, and therefore of sufficient size for close
observation. It appears to be a solid body
with annular muscular bands, capable of ex-
tension and contraction.

The juices of the flowers are conveyed along
the tongue to the receptacle at the base of
the labial palpi. Each of these labial palpi
is terminated by three jointed articulations,
which must add greatly to the efficiency of
the palpi, most probably constituting them
special organs of touch.

At the base of each maxilla are the man-
dibles. In wasps as well as bees these organs,
according to several observers, supply the place
of trowels, spades, pick-axes, saws, scissors, and
knives, as necessity may require.

Taking into account all the varied functions

FIG. 22

TONGUE OF HONEY BEE.
X20.

[to face page 86.

LEG OF HONEY BEE 87

of the apparatus known as the bee's tongue
and its adjuncts, and the enormous amount
of work it does for man, one is appalled at
its minuteness, its complexity, and- its ex-
cellence.

The photo-micrograph from which the illus-
tration (Fig. 22) was taken shows the object
amplified to 36 diameters; the focal distance
was 72 inches ; the time of exposure to
gas-light two minutes, and the objective used
was the 2 inch.

Leg of Honey Bee.

(Apis mellifica.)

The hind legs of these indefatigable creatures
are used as implements in their daily work.
There is a series of modifications in the hind
legs of the male, queen, and worker, so that
all are different. Those of the worker are
modified more highly to adapt them to their
industrial occupations. This fact in Nature
always arouses the keen interest of naturalists,
in consequence of the difficulty that exists in
connection with the creature's heredity, for

88 LEG OF HONEY BEE

neither of the parents is endowed with this
excessive modification of the hind legs. It is
admitted to be * a very special adaptation
appearing in the majority of the individuals
of each generation, though nothing of the sort
occurs in either parent.' *

Among the many functions of the workers'
hind legs is that of acting as receptacles for
carrying pollen to the nest or hive. The parts
most modified are the tibia and the first joint
of the tarsus or foot. In many bees other
parts of the body carry pollen. Sometimes
the hind legs are thick and densely covered
with hairs that hold the pollen in a dry
state until it is carried home.

At times the outer face of the tibia is free
from hairs except at the margins, in which
case pollen plates are supposed to exist. In
this case the pollen is said to be mixed with
nectar from the bee's mouth and rendered
plastic.

The inner side of both tibia and tarsus,
especially the latter, is covered with hairs;
* Cambridge Natural History.

FIG. 23.

PART OF HONEY BEE'S HIND LEG.
X25.

{.to face page 88.

FIG. 24.
GNAT (CULEX PIP1ENS).

[to face page 89.

ARRANGEMENT OF HAIRS 89

those on the tarsus are arranged as in a
brush, and are used for brushing the pollen
from the flowers into the various receptacles
on the creature's legs and body. The brush
arrangement of hairs is noticeable in the
illustrations.

The illustration (Fig. 23) is from a photo-
micrograph of 45 diameters ; the focal distance
was 70 inches, and the objective used was the
2 inch.

6 *

CHAPTEE VII

MOSQUITO, AN INSECT NAVVY, AND
RHYNGIA

The Mosquito.

A SCEKTAINING the life-history of the
-£•*- mosquito is one of the grand achieve-
ments of modern times. Several prominent
medical experts have taken an enormous
amount of trouble in this direction, and have
even risked their lives in their desire to find
some reliable means of combating or prevent-
ing malarial fever, the germs of which are
carried by the mosquito.

Malaria, or ague, is a disease peculiar to
man, and it is caused by an extremely minute
parasite which lives in the red corpuscles of
the blood. The malaria parasite is transmitted
to man by the * stab ' of the mosquito.

In the main hall of the Natural History

90

MODELS OF MOSQUITOES 91

Museum, Cromwell Koad, are models of mos-
quitoes twenty-eight times as large (linear
measurement) as the original insects, which
are placed beside them for comparison for
educational purposes.

The common mosquito (Gulex pipiens) which
we frequently see on our window-panes does
not transmit the malaria parasite. The spot-
winged mosquitoes (Anopheles maculipennis),
abundant in England and nearly all parts of
the world, are carriers of the malaria parasite.
The parasite multiplies not only in the human
blood, but in the stomach and tissues of the
mosquito.

Various forms of malaria are distinguished
by medical men according to the frequency
of the recurrence of fever and other symptoms,
as Tertian, Quartan, &c. Each is due to
a distinct species of parasite, though the
differences are very slight.

The life-history represented by the models
referred to is that of the parasite of the
so-called ' pernicious ' or < sestivo-autumnal '
malarial fever. The malaria parasite is an

92 THE MOSQUITO

animal belonging to^the lowest grade of Pro-
tozoa, and is allied to the Gregarines. Malaria
was formerly common in England ; it was then
known as ague. It is now extinct in this
country, but is common in Southern Europe
and the Tropics, where it causes disastrous
sickness and many deaths. The foregoing
particulars have been obtained from the de-
scriptive matter accompanying the models in
the glass case.

In the illustration (Fig. 24) the common
window-gnat (Gulex pipiens) is shown. The
original photo-micrograph has an amplification
of 15 diameters; the focal length was 45
inches ; the time of exposure was half a
minute ; and the objective used was the 3 inch.
In the next illustration (Fig. 25) * the dan-
gerous mosquito (Anopheles maculipennis) is
represented with its proboscis extended. The
original photo-micrograph shows an amplifica-
tion of 21 diameters ; the focal distance was
82 inches ; and the objective used was the
3J inch.
* From a micro-slide supplied by Messrs. E. <& J. Beck.

MYRMELEON 93

The close arrangement of tiny hairs on
different parts of the wings gives rise to the
spotted appearance, and to the creature's second
name, maculipennis.

An Insect Navvy.

(Myrmekon.)

This most remarkable insect — the Ant-lion
— in its larval state, is, if we are to judge by
its methods of work, a navvy, and is amongst
the most wonderful creatures in the insect world.

It is endowed with powers of a surprising
order, and it displays an ingenuity equal
to that shown by many larger animals that
occupy a much higher position in the animal
world.

The insect must not be judged by its
appearance. This applies to creatures in a
higher order of life.

Before we enter into its special claims upon
our attention by enumerating any of its
remarkable doings it is necessary to say some-
thing about its life-history.

94 AN INSECT NAVVY

4 When the larva is full grown it forms a
globular cocoon by fastening together grains of
sand with fine silk from a slender spinneret
placed at the posterior extremity of the body.
In this cocoon it changes to an imago of very
elongate form, and does not emerge until its
metamorphosis is quite completed, the skin of
the pupa being, when the insect emerges, left
behind in the cocoon. We have no Ant-lions
inhabiting Great Britain, though specimens
introduced do very well in confinement.'

The famous naturalist Keaumur gives us an
interesting account of the creature's habits :
1 The larvae are predaceous, and secure their
prey by means of pitfalls they excavate in the
earth, and at the bottom of which they bury
themselves, leaving only their elongated jaws
projecting out of the sand at the bottom of
the pit. It is a very unusual circumstance in
insect life that the larva of the Ant-lion can
only move backwards. In forming their pit
they use their broad bodies as ploughs, and
throw out the sand by placing it on their
heads and then sending it to a distance by a

FIG. 26.
LARVA OF ANT-LION.

X 14.

to face page 94.

REAUMUR'S ACCOUNT 95

sudden jerk. When about to construct a trap
the larva does not commence at the centre,
but makes first a circular groove of the full
circumference of the future pit. Burying its
abdomen in the surface of the earth, the
insect collects on its head, by means of the
front leg, the sand from the side which is
nearest to the centre, and then jerks the sand
to a distance. By making a second circuit
within the first one, and then another, the
soil is gradually removed, and a conical pit is
formed, at the bottom of which the Ant-lion
lurks, burying its body, but leaving its for-
midable mandibles widely extended and pro-
jecting from the sand. In this position the
young Ant-lion waits patiently till some wander-
ing insect trespasses on its domains. An ant
or fly coming over the edge of the pitfall
finds the sand of the sloping sides yielding
beneath its body, and in its efforts to secure
itself probably dislodges some more of the
sand, which, descending to the bottom of the
pit, brings the lurking " lion " into activity.
Availing himself of his power of throwing sand

96 AN INSECT NAVVY

with his head, the Ant-lion jerks some in the
direction of the trespasser, and continues to
do so until the victim is brought to the bottom
of the pit and into the very jaws of its de-
stroyer. The position chosen for the pitfall is
in a place that will keep dry, as the larva
cannot carry on its operations in damp or wet
sand.'

This description of the Ant-lion's tactics is
taken from The Cambridge Natural History,
and fully shows the reasons for naming the
creature an ' insect navvy.'

It is also remarkable that the Ant-lion has
no true mouth, or orifice resembling a mouth,
yet the parts which take its place are perfectly
adapted for enabling it to empty its prey of
its juices.

The pharynx is provided with a complete
set of muscles, and, together with the buccal
cavity, performs the functions of an instrument
of suction.

The Ant-lion is also remarkable in that it is
capable of sustaining prolonged fasts. Dufour
kept specimens for six months without any

•' -

FIG. 27.
RHYNGIA.

xiS.

^«^ 96.

RHYNGIA 97

food. It is to be hoped the creatures sur-
vived. The authority just quoted does not
carry the account of the experiment further.

The Myrmeleon formicarius is found in
Ceylon.

The illustration (Fig. 26) of this most re-
markable insect is taken from a photo-micro-
graph of 24 diameters ; the time of exposure
to gas-light was two minutes; the focal dis-
tance was 48 inches, and the 2-inch objective
was used.

Rhyngia.

This insect is generally known as the ' Snout
Fly/ A portion of the extreme end of its
proboscis is shown on the title-page (Fig. 2).
The illustration (Fig. 27) is from a negative
of 18 diameters, while that on the title-page is
from a negative of 95 diameters.

CHAPTER VIII

HEAD OF CRANE FLY AND ANTENNA
OF MELOLONTHA

Head of Crane Fly.

(Tipula.)

Crane Fly, or c Daddy-long-legs/ as
it is commonly called, is a curious insect,
and is known all over the world, the family
being a very large one and found everywhere,
irrespective of extremes of climate, altered
conditions of plant-life, or any of those great
changes which completely alter the character
of living things in general.

Some of its representatives extend their
range even to the most inclement climates,
where other insects could not exist.

So far, our naturalists tell us, it is impos-
sible to assign any reason of utility for the

FIG. 28.

HEAD OF CRANE FLY.
XI5

[to face page 99.

4 DADDY-LONG-LEGS ' 99

extreme elongation of the legs of these insects.
Doubtless there is a reason, which will be dis-
covered when we know the full particulars of
its life. ' As every one knows, the legs break
off with great ease, and the insect appears to
get on very well without them. It is fre-
quently the case that they are much longer
in the males than in the females. Other parts
of the body exhibit a peculiar elongation ; in
some forms of the male the front of the
head is prolonged into a rostrum. The larvae
exhibit a great variety of form, some being
terrestrial, others aquatic ; but the terrestrial
ones seem all to delight in damp situations,
such as shaded turf or rotten tree-stems.
There are more than a thousand species of
these flies known and many genera.'

In the illustration (Fig. 28) the eyes of
the insect attract special attention and the
highest admiration from every one who studies
them. They are faceted, and are of wonderful
complexity and delicacy.

They are totally different in structure and
very distinct in function from the eyes of the

ioo THE CRANE FLY

vertebrate animal, and are seated on very large
special lobes of the brain. These lobes, indeed,
are so large and so complex in structure that
the insects may be described as possessing
special ocular brains brought into relation with
the lights, shades, and movements of the ex-
ternal world by a remarkably complex optical
apparatus.

The illustration is taken from a photo-micro-
graph representing a portion of the insect as
if amplified to 35 diameters. It is the result
of one minute's exposure to gas-light. The
focal distance was 70 inches, and the objective
used was the 2-inch.

Antenna of Melolontha.

This object, one of the antennae of the
cockchafer, is well adapted for photographic
purposes, and can even be sketched in outline
with great ease by using the camera lucida.

Throughout the whole surface of this com-
pound appendage an enormous number of
small circular cavities is observable. If

FIG. 29.

ANTENNA OF COCKCHAFER (MELOLONTHA).
XI5-

[to face page 101.

ANTENNA OF MELOLONTHA 101

modern observations be correct, these tiny
cavities have an important duty to perform,
and a great gain has been made with regard
to our knowledge of this creature.

Dr. Hicks, in his work On a New Structure
in the Antennce of Insects, seems to show
conclusively that the sense of hearing is
inseparably connected with these innumerable
concavities spread over the divisions or
appendages that make up an antenna.

Burmeister suggests that a soft articulating
membrane at the base of each antenna, which
can be rendered tense or otherwise by the
movements of the antenna, represents the
drum of the ear ; also that it is so placed as
to receive impressions of sound vibrations.

That the insects possess the sense of hearing
need not be doubted.

The wonderful antennae of the melolontha
doubtless have special duties to perform as
well as to act as receivers of sound waves.
They are organs of touch; this sense is
bestowed upon all insects, and to judge from
the perfection of the structures which some

102 ANTENNA OF MELOLONTHA

insects build, and the mathematical accuracy
of their work, their sense of touch must be
extremely delicate. This sense is generally
believed to be specially localised in the
antennae.

The varied movements of the lamellae of
the antennae of the cockchafer may be realised
by the opening and folding over of the several
divisions of a carved ivory fan.

The original photograph of this antenna
(Fig. 29) shows an amplification of 36 dia-
meters. The time of exposure was 4 minutes
to gas-light ; the focal distance from plate
object was 72 inches. A 2-inch objective
was used.

see page no.

FIG. 30.

DIATOM, NAVICULA LYRA.
X900

[to face page 103.

CHAPTEK IX
DIATOMS

"T^vIATOMS constitute a group of microscopic
-*-^ plants found all over the world in most
waters — fresh, brackish, or salt. They are
yellowish-brown in colour, and consist of a
single cell, free or adhering in chains or
planes. A coat of silica invests the plant.
This coat is composed of two valves, generally
alike, joined together by connecting girdles.
It is the opinion of some authorities that
the flinty structures are skeletons arranged
in symmetrical halves and joined at their
margins by an intermediate rim or hoop.
The valves are of various forms, and their
surfaces exhibit delicate markings. Many of
these united valves or skeletons are not

103

104 DIATOMS

unlike pill-boxes, each with a lid, bottom, and
rim. Some are oblong, others sigmoid, ellip-
tical, triangular, &c.

Diatoms were formerly placed in the animal
kingdom, chiefly because they are able to
move. A more exact study of their structure
and mode of nutrition shows that they must
be classed with the lower Algae.

Diatoms increase in number by successive
division into two, in such a manner that suc-
ceeding generations are diminished in size.
This diminution is owing to the fact that the
wall of the older portion overlaps that of the
younger, and the diminution therefore corre-
sponds in extent with the thickness of the
wall. This process goes on through a series
of generations, the minimum size being about
half the maximum. When the minimum is
reached, the wall is cast off, the contents
become rounded in form and increase in
size, and a new individual of the maximum
size is produced. The late Professor W.
Smith estimates that no less than a thou-
sand million individuals may be produced

DEPOSITS OF DIATOMS 105

by division from a single plant in one
month !

Vast numbers of these organisms are
peculiar to the open sea, and they possess a
sufficient degree of buoyancy to enable them
to live and to move amongst its waters with-
out the aid of any supporting body whatever.
Their buoyancy and power of movement are
entirely independent of the ordinary to-and-
fro motile power shared by them, in a greater
or less degree, with all the other free forms
of Diatomacese.

It is impossible to conceive the extra-
ordinary abundance of diatoms throughout
the world. According to Ehrenberg, they
have exercised an important influence in
blocking up harbours and diminishing the
depths of channels. A mud deposit, consist-
ing, chiefly, of their siliceous valves, no less
than 400 miles long by 120 miles broad, was
found at a depth of between 200 and 400 feet
on the flanks of Victoria Land in 70° south
latitude.

Deposits of diatoms are found in tertiary

io6 DIATOMS

and post-tertiary strata. The Bergmehl of
Norway is composed of fresh-water species.
Small deposits have been found underlying
beds of peat in Great Britain and Ireland. A
bed 25 feet in thickness, composed entirely of
marine species, and extending over a large area,
occurs at Eichmond, in Virginia. Similar beds
exist in other countries.

No mind, however mathematical, can have
any conception of the numerical strength of
these lowly yet magnificent organisms. For
example, in the Botanical Department of the
Natural History Museum, Cromwell Koad, a
glass case contains a block not more than
two cubic feet in measurement. It contains
not fewer than 12 billion (12,000,000,000,000)
individual plants ! This block representing so
much life could be carried under the arm
with ease. Figures must fail to help us when
trying to form an idea of the life repre-
sented in the deposit in the Antarctic Ocean,
48,000 miles in area, or in the fossil deposit
of Virginia.

With regard to this almost cubical block,

FIG. 31.
DIATOM, TRICERATIUM FAVUS.

x 600.

see page no.

[to face page 106.

REV. F. WOLLE'S OPINIONS 107

the contents of the cells and the whole tissue
of the plants have gone except the siliceous
coats. The mass is from a fresh-water lake
in Australia. Year after year the diatoms
in myriads lived for a short time in the
water; when dead, the organic portions
decayed, and the remaining imperishable
siliceous coats fell to the bottom of the lake,
and in time formed the pure deposit of
which this is a fragment.

' As regards the longevity of diatoms/
says the Kev. F. Wolle (Diatomacece of North
America), l it may be said that dried speci-
mens cannot be revived, but they have been
known to survive nearly a quarter of a
century in their natural element, even though
kept for long periods in the dark, and at
times frozen in solid ice. Their siliceous
covering is almost indestructible, resisting the
strongest acids and passing unscathed through
very high degrees of heat.'

Specimens for mounting can readily be
collected in a wide-mouth bottle, with some
fine muslin to act as a net. When the

108 DIATOMS

diatoms are attached to the stems of other
plants under water, it is best to remove the
stem with its specimens. Very frequently,
however, they are only entangled in the
meshes of confervse, and can be obtained by
the usual ring net employed by microscopists.
The surface mud of ponds generally contains
large supplies of beautiful representatives of
this remarkable family. To separate them
from the sand, &c., the contents of the
bottles should be placed in distilled water
and allowed to remain for a time, when
the sand, being the heavier, will collect at
the bottom, and the diatoms may be
skimmed off.

A few words more as to the markings
which the surfaces of the diatoms exhibit.
Some of them are arranged in lines, parallel
or radiating, or assume the outline of the
individual specimen. Some markings appear
as dots, others as if crossing each other.
Many naturalists believe that the markings
are depressions, but as different effects may
be obtained by different methods of illumina-

FIG. 32.

DIATOM, TRICERATIUM FAVUS, VAR. SEPTANGULATUM.
X280.

see page n

io8.

SYMMETRICAL MARKINGS 109

tion, the question of hemispherical elevations
or cup-like sculpturings is by no means
settled. It remains, however, that these tiny
objects, although so very small that many of
them are on the borders of our vision, or
even below unassisted sight, are decorated
with thousands of lines and markings in
fixed, definite, symmetrical order, each kind
of diatom having its own special markings
characteristic of its group. Very high powers
of the microscope reveal not only surface or
primary patterns, but also secondary or even
tertiary markings. Mr. E. M. Nelson, who is
deservedly looked upon as a recognised
authority on the study of these wonderful
products of Nature, admits that even with
the highest microscopical powers he is not
able to exhaust or reach the limits of design
in a diatom ! Complex designs involving the
symmetrical arrangement of many thousands
of lines and dots on a speck of flint that is
too small to be seen without a microscope !
The seven artificially-constructed wonders of
the world, whatever they may be, are not to

no DIATOMS

be compared with these marvels of regularity
and exquisite beauty.

To illustrate this chapter there are sis
pictures. The first is taken from a photo-
micrograph of 1,500 diameters. The diatom
is Actinocyclus ralfsii (Fig. 6). Under the
microscope this object gives a display of colour
very much resembling the action of a diffrac-
tion grating.

The second is a magnificent diatom (Fig. 5).
In the original photo-micrograph it shows an
amplification of 2,500 diameters ! It was found
in clay in Hungary.

The third is Navicula lyra (Fig. 30). The
illustration is from an amplification of 1,500
diameters ; the exposure was 60 minutes ;
the focal length 40 inches; an eye-piece
of 7 diameters; and the ^th objective were
used.

Next comes the ' sun shield/ Heliopelta
metii (Fig. 3). The illustration is from a
photo-micrograph taken under a magnification
of 580 diameters. No collection of diatoms
can be representative without this specimen.

FIG. 33.

SECTION OF WHEAT-STEM.
XI5.

[to fact page no.

DIATOMS ill

Triceratium favus (Fig. 31) follows, and is
from an amplification of 1,375 diameters.

The next illustration (Fig. 32) is that of
Triceratium favus, var. Septangulatum, and is
from an amplification of 640 diameters.

The last illustration (Fig. 4) of the diatom
series is from a photo-micrograph of 1,750
diameters. Only a small portion of this diatom
is seen. It is that of Coscinodiscus bi-angulatus.

That there are thousands of markings on the
surface of any one of these diatoms is evident.
If we try to realise this fact — and that several
diatoms are so small that we can barely see
them, while many are completely below the
powers of the strongest eyes — we shall have
something that will test our thinking-powers,
and that may induce us to take a deeper
interest in Nature-study.

CHAPTEE X

SECTIONS OF WHEAT STEMS, AND
DODDER ON CLOVER

Section of Wheat Stem.

E illustrations reveal a marvellous
-*• arrangement of cells in simple sections
of an ordinary plant. The perfect order and
the way in which they are all disposed in so
limited a space as the thickness of a stem
of wheat is most surprising. There are few,
if any, of our grasses which have a more
remarkable history than that of the common
wheat, Triticum vulgare. For this, and for
other apparent reasons, information about this
plant should be well studied by everybody.
The plant is, of course, known to every one;

but few are aware that it is derived from a wild

ua

FIG. 34.
SECTION OF WHEAT-STEM THROUGH THE NODE.

\to face page 113.

^GILOPS 113

grass of Southern Europe and Western Asia.
That a wild and apparently useless grass, very
dissimilar from wheat, should by careful culti-
vation become so changed as to afford a useful
and nutritious grain for the food of many
nations in countries widely separated, is a
proof of the advantages of civilisation, what-
ever may be advanced against it. But this
is not all. Its adaptability to circumstances
renders it capable of easily affording a large
series of varieties. No plant is so easily
adapted to the variations of climate, soil, and
management as is wheat. It has a wider geo-
graphical range than most plants. Eice, maize,
and wheat may be said to support the greatest
number of the human race.

The eminent botanists, M. Fabre in France,
and T. Moore, of The Treasury of Botany
fame, have taken the wild grass ^Egilops and
placed it under modern methods of cultivation.
In the course of a few years, they had the
gratification of seeing good ears of wheat
gradually emerging, as it were, from the
formerly wild grass. Many of the plants rose

8

114 WHEAT STEMS

to 2 feet in height with spikes and flowers
containing as many as twelve spikelets.

The genuineness of the connection between
the grass JEgilops and our wheat is established
by the fact that the bruised foliage of the wild
grass and the cultivated wheat both emit the
same odour ; still further, both are subject to the
attacks of the same species of parasites (blights).

Wheat and other cerealia contain in their
herbage, and especially in their seeds, nutri-
tious principles which entitle them to take first
rank amongst the plants useful to man, and
of the greatest importance from an economic
point of view.

Besides starch, sugar, and mucilage, they
yield sulphoazotised matters such as fibrin,
casein, albumen — elements essential to the
formation of flesh in animals ; especially do
they yield phosphate of lime, the basis of their
bony framework.

A very curious experiment can be performed
with a growing stem of wheat. There are to
be noticed, at considerable distances apart,
certain knot-like swellings — nodes — sharply

GEOTROPIC CURVATURE 115

marked off from the thin cylindrical parts and
usually coloured differently. One of these
knots with a portion of the stem above and
below, comprises a ' haulm.1

'If a haulm be bent sharply above the soil,
while growing, so that the whole of its upper
part comes to lie horizontally, it will be noticed
after from two to four days that a knee-like
curvature has been formed at its node, in con-
sequence of which the apical portion of the
haulm again erects itself vertically ; as a rule
two or three nodes take part in this change,
the nodes being about the knee-like formations.
The result is known as geotropic curvature.
The curvature of the node is due to the fact
that its under side, when placed in the un-
wonted horizontal position, becomes consider-
ably elongated as a result of vigorous growth,
while the upper side grows feebly or not at all,
or even often becomes considerably shortened.

* If a scarlet runner growing erect in a vessel
be inverted and left upside-down for some hours,
it will, even in that short time, show geotropic
curvature of the mobile organs.' (Sachs.)

Il6 WHEAT STEMS

The illustration (Fig. 33) is taken from a
photo-micrograph of 36 diameters. It was
done on a process plate owing to the section
being exceptionally weak. The time of ex-
posure was 3 minutes ; the focal distance was
36 inches, and the objective used was the
1-inch.

It will be observed that this portion of the
stem is a hollow cylinder. The fact is that the
original central cellular tissue was torn up and
destroyed in the process of growth. Surround-
ing the central hollow is the cellular tissue,
while the dark patches are fibro-vascular
bundles. The outer dark margin consists of
closely-packed epidermal cells.

In the next illustration (Fig. 34) we have
a section through one of the nodes. The
epidermal cells constitute, as in the previous
instance, the thin outer limits of the stem.
The wide band inside these limits is the sheath,
or base of the leaf, containing fibro-vascular
bundles in the midst of cellular tissue.

Further in we have the stem within the leaf,
also with fibro-vascular bundles. The central

THE PARASITIC DODDER 117

cellular tissue is here intact, being young.
This illustration is also taken from a photo-
micrograph of 36 diameters ; the focal distance
was 36 inches ; and a 1-inch objective was
used.

Dodder on Clover.

The dodder is not only devoid of roots and
leaves in the strict sense, but is destitute of
green colouring matter, the substance which
helps to elaborate the food of plants, and
occurs so abundantly in clover, from which
dodder draws its nutriment. It does not
possess any of the small mouths or organs of
transpiration possessed by ordinary plants.

It is also remarkable in another respect. It
is generally agreed that dodders produce an
acrid and purgative juice, detrimental to flocks
and herds. The question naturally arises,
Where do they obtain these injurious principles ?
It is certainly singular that a parasitic plant
should be capable of elaborating acrid juices
from the sweet non-acrid sap of its host.

n8 DODDER ON CLOVER

A plant exhibiting so many exceptions to
the laws which govern ordinary plant-life
must of necessity possess some points of
interest in its structure and habits. Omitting
minute details, dodders are plants with
yellowish or reddish, leafless, threadlike stems,
the leaves being represented by a few small
transparent scales. The small bell-shaped
flowers are packed closely together in clusters.
The threadlike stems are furnished with
numerous very small suckers with which the
parasite attaches itself to its host.

It is extremely common to find seeds
of dodder amongst impure clover seeds im-
ported from the Continent. It is not always
easy to sift dodder from the clover. Clover
seeds send their roots deep into the earth,
while the dodder seeds are sending their
threads into the air in search of a host on
which to live parasitically. Ultimately they
succeed in reaching the young clover seed-
lings. When the dodder twines round a
seedling clover the rapidly-growing clover
carries the dodder away from the ground. As

FIG. 35.
DODDER OX CLOVER.

\toface pa

METHOD OF SPREADING HQ

the clover grows the dodder grows with it,
and the parasite is lifted higher from the
ground. As the spring and summer advance,
the dodder flowers profusely, and as the clover
plants grow in size and come in contact
with each other, the dodder spreads from one
host to another. The dodder, in growing,
branches and re-branches repeatedly, and throws
out long arms, so that during a single
summer one or two infested clover plants will
help to spread the dodder over a large area.
The parasite cannot live on the remains of
the plants it has destroyed, so, in the process
of growth, it leaves the central clover plant
for other plants at the circumference of a
dead circle of clover, which may be many
feet, or even yards, in diameter.

The suckers, already mentioned as being
useful to the dodder in enabling it to attach
itself to the clover, are pushed into the fine
longitudinal furrows (which are always present
on clover stems) until they reach the internal
cellular structure of the clover. Each sucker
being provided with a woody skeleton, it acts

120 DODDER ON CLOVER

like a small thorn, and is thus enabled to
pierce the clover stem. The parasitic life of
the clover dodder commences with the inser-
tion of the first sucker into the host plant.
When the pith is reached by the suckers
pushing themselves in between the cells of
the stem of the host, the cellular tissue of
the dodder comes into close contact with the
living cells of the clover, with the result that
the vital juices elaborated by the clover pass
through the cell walls of the clover into the
cells of the dodder ; thus the sap of the clover
feeds the parasite by transfusion.

The dodder grows with such extraordinary
rapidity when it has once fixed on clover, and
it produces so many branches and branchlets,
with such a vast number of suckers, that
the growth of the parasite usually far exceeds
that of the host. The consequence is the
dodder completely drains out the elaborated
juices of the clover, and kills it by exhaus-
tion. The destruction of the clover is also
hastened by the great weight of the accu-
mulated masses of entangled dodder. Every

ITS SUCKERS 121

patch of dodder should be carefully raked
together and burnt, and by this process and
careful sifting its appearance in the fields can
generally be prevented.

In the illustration (Fig. 35) part of the
enclosing stem of the dodder is seen with
three of its suckers inserted in the almost
circular section of the clover stem. In the
original photograph an amplitude of 80 dia-
meters is shown ; the focal distance was 40
inches; the exposure to gas was 5 minutes,
and the half -inch objective was used. The
section of the clover stem displays a beautiful
arrangement of cells.

Looking again at the section, the outer
margin of the portion of dodder shown con-
sists of cellular tissue; next to that is the
woody cylinder. The three suckers of the
dodder are distinctly seen inserted in the
clover. With regard to the clover part of the
section, we see inside the margin about ten
nbro-vascular bundles ; all the remaining cells
towards and at the centre are loose cellular
tissue.

122 DODDER ON CLOVER

All the foregoing details descriptive of the
dodder I have taken from Mr. Worthington
G-. Smith's excellent work on Diseases of
Field and Garden Crops.

FIG. 36.
STING OF NETTLE.

X55

[to face page 123.

CHAPTER XI

STING OF NETTLE, ARISTOLOCHIA
GIGAS, AND CALAMUS ROTANG

Sting of Nettle.

rr

-*-

sting of a nettle is shown in the
original photograph amplified to 100
diameters. In reality the sting is a plant
hair which is tubular, unicellular, sharply
conical, and terminating at the top in a small
knob, which in this instance has been broken
off. At the base the sting, or hair, broadens
out, is bulb-like, and fits into a cup which is
developed from the tissues of the leaf. The
bulb contains the acrid fluid which causes so
much pain, and frequently raises blisters on
the hand that touches it. As the hand is
rubbed against the nettle the knob is broken

123

124 STING OF NETTLE

off the sting, and immediately a free passage
is made for the irritant fluid to pass into the
wound. If the sting be broken off below the
point, as is the case when it is grasped firmly,
the poison is poured on the skin instead of
underneath it, and is not felt.

In this country we are more fortunate as
regards the nettles than our friends in Aus-
tralia. In New South Wales some nettles,
notably the Urtica gigas, are formidable trees
in more senses than one, and they frequently
form a great impediment to the traveller.
They vary in size from 20 feet to 120 feet in
height. Their leaves attain a breadth of 15
inches. The poisonous fluid secreted from the
foliage is excessively virulent, especially in the
younger leaves. It produces intense pain, and
often leads to dangerous results.

There is, however, another side to the life-
history of the nettle. In all countries in
which the nettle thrives it is a most useful
plant, whatever the species may be. The
stinging-nettle of our hedges and roadsides —
Urtica dioica — is cooked and eaten as a vege-

NETTLES AS FOOD, ETC. 125

table. The Belgians and Germans use it for
this purpose more than we do. In this form
it is looked upon as a blood purifier.

Sir Walter Scott mentions the fact that
the nettle was cultivated in Scotland as a
potherb.

The young tops of nettles, when dried, form
a good food for cattle. The fresh tops are
enjoyed by pigs, and when chopped up they
make an excellent food for fowls and young
turkeys. Both the dried leaves and the seeds
are given to fowls in winter-time to make
them lay eggs. In Holland and other coun-
tries, horse-dealers mix seeds of nettles with
oats or other food to give the animals a sleek
coat. Many of the nettle tribe have medicinal
properties — astringent, aperient, diuretic, &c.
The excellent fibres they produce are used for
making hemp, ropes, cordage, fishing-lines,
cloth, and even lace. Specimens of lace from
nettle fibre made by peasant women in Ire-
land may be seen in the chief museum in
Kew Gardens.

Looking fairly at the shortcomings and the

126 ARISTOLOCHIA GIGAS

virtues of the nettle family, we are bound
to conclude that the latter outweigh the
former, and that nettles are most useful
plants, even if troublesome when touched in-
cautiously. There are one or two facts about
the nettle which we must not omit to notice.
The ease with which the sting penetrates the
human skin is accounted for by the fact that
its walls are composed of flint, as may be
easily proved by heating it red-hot on a plate
of mica. If the sting be carefully removed
from the growing plant, the streaming of the
protoplasm can be distinctly seen. The cuticle
shows oblique striation, which ascends in the
same direction in all stings.

As already stated, the illustration (Fig. 36)
is from a photo-micrograph, showing the sting
as if enlarged to 100 diameters ; the focal dis-
tance was 45 inches, and a half-inch objective
was used.

Aristolochia gigas.

A section of this remarkable plant is shown
in the illustration. Its peculiarity is at once

MICROSCOPIC STRUCTURE 127

noticeable in the arrangement of its vascular
bundles in the shape of separable wedges, and
in the absence of concentric rings or zones.
The wood of this plant differs in appearance
from that of exogenous trees or shrubs, as it
consists of radiating plates of wood surrounding
a pith and encircled by bark.

The section shows at the centre the pith
containing cells, and around this a belt of
isolated vascular bundles in which the wood is
the darker portion, pierced with holes, which
latter are sections of vessels.

The plants of this genus are for the most
part shrubs, generally climbing round the
branches of trees. They abound in tropical
South America.

The flowers of some of the kinds are remark-
able for the oddity of their forms and for their
large size. Humboldt mentions one growing
on the banks of the Magdalena as having
blossoms, measuring 4 feet in circumference,
which the Indian children sportively draw on
their heads as caps.

Several kinds of Aristolochia are cultivated

128 ARISTOLOCHIA GIGAS

in hothouses in England for the singularity
and handsome appearance of their flowers,
although their colours are by no means
brilliant.

The flowers of various species act as fly-
traps. They are bent in the middle and are
lined with hairs pointing downwards, so that
ingress is easy, but escape impossible to the
insect, which ultimately aids in the ripening
of the seed.

The plant, especially the root, possesses
many kinds of medicinal qualities, several of
which could only be referred to in a medical
work.

So satisfied are the natives of Mexico, Peru,
and Central America of its extraordinary
medicinal properties and specific virtues in
cases of snake-bite, that every Indian or negro
who has to traverse the country invariably
has a supply of this friendly plant in a dry
or prepared state, to meet any accident that
may befall him from inadvertently placing his
foot upon one of these dreaded and deadly
foes of mankind.

FIG. 37-

STEM SECTION, AR1STOLOCH1A GIGAS.
XI4.

[to face page 128.

MICROSCOPIC STRUCTURE 129

The illustration (Fig. 37) is taken from
a photo-micrograph of 32 diameters ; the
time of exposure was 5 minutes ; the focal
distance was 48 inches ; and the objective
used was the inch and a half.

Looking more closely at the section we see
certain dark portions at intervals on the
margin ; these are the bases of the leaves ;
next comes the bark; pointing towards the
centre are radiating plates of wood with
large air passages ; between these and the
bark are plates of wood running concentrically
with the bark; these are held loosely together
by soft, medullary processes. In the centre
is the cellular pith.

This is an example of an aberrant exoge-
nous stem.

Calamus Rotang.

The Calamus rotang is one of the chief
species of palms that furnish the canes and
rattans used in this and other countries for
bottoms of chairs, couches, sides of carriages,
and similar purposes.

9

130 CALAMUS ROTANG

In the countries where these canes abound
— the Malayan Peninsula and other parts of
Asia — the natives use them for a great variety
of purposes ; baskets of all kinds, mats, hats,
and other useful articles being commonly made
of them.

Their most important use, however, is for
the manufacture of ropes and cables usually
employed by coasting vessels. In the Hima-
layas they are used in the formation of
suspension bridges across rivers.

Dr. Hooker thus describes their con-
struction : < Two parallel canes, on the same
horizontal plane, were stretched across the
stream ; from these others hung in loops, and
along the loops were laid one or two bamboo
stems for flooring ; cross-pieces below this
flooring hung from the two upper canes,
which they thus served to keep apart. The
traveller grasps one of the canes in either
hand and walks along the loose bamboos
laid on the swinging loops.'

In the natural state the canes have reed-
like stems, seldom more than an inch in

FIG. 33.
STEM SECTION, RATTAN CAM: (CALAMUS ROTANG).

x 14

[to face page 131.

CELLULAR STRUCTURE 131

thickness, but often much less, generally
growing to a great length, climbing over and
amongst the branches of trees. The stem
has long internodes, the leaves being situated
at some distance from one another. Some-
times in Ceylon and the Malay Islands the
cane attains to the length of 300 feet. They
fling, so to speak, their long shoots on the
jungle and on the branches of trees, and
hang there by means of their hooks.

The illustration (Fig. 38) is taken from a
photo-micrograph o* 30 diameters ; focal
distance, 30 inches ; the 1-inch objective was
used.

The section shows the reed-like structure
of the palm — Calamus rotang — an example
of an endogenous stem without medullary
rays.

Commencing at the outside, the outer
hard, dense part consists of closely-packed
epidermal cells. Next to this are vascular
bundles right round within the margin ; the
smallest cells which predominate throughout
the section are simply cellular tissue ; the

132 CALAMUS ROTANG

older part of the cane is next to the
vascular bundles of the marginal series;
then there are vascular bundles scattered
about, each containing a large white cell,
but those assuming the shape of the letter
V enclose within their range the newer part
of the cane.

FIG. 39.

SECTION OF LILY BU.O.
X 12.

[to face page 133.

CHAPTER XII

BUD OF LILY, VIRGIN'S BOWER, AND
PETIOLE OF NUPHAR LUTEA

Bud of Lily Section.

OF the lily itself no description is necessary.
A glance at the section of its bud shows
an amount of geometrical arrangement that
is, in no small degree, surprising, Triangles,
circles, hexagons, and even trapeziums find a
place in its small dimensions. Minute cellular
tissue is to be seen in all portions of its
structure.

Beginning at the outside, we notice sections
of six separate parts : these are the petals
peculiar to all lilies. Each shows cellular
tissue and nbro-vascular bundles. Then come
six stamens, each containing a pair of two-

133

134 BUD OF LILY AND CLEMATIS

celled anthers which contain pollen. Each of
the six stamens contains a filament. In the
centre is a separate mass that could be en-
closed in a six-sided figure. This is the ovary,
but only the upper portion, without ovules.

The illustration (Fig. 39) is from a photo-
micrograph of 25 diameters ; the focal distance
was 50 inches ; and the objective used was the
2-inch.

Virgin's Bower.

(Clematis vitalba.)

The Clematideae are well known for their
ornamental plants. Almost all the genera
have species which are cultivated for their
great beauty. They are not endowed with
sweet-scented flowers, neither have they the
insect-loving honey. Still, the insects visit
them for their pollen. The clematis is a
twining shrub belonging to the Eanunculaceae,
among which they are known by their single-
coloured calyx without petals, and by the long
feathery tail attached to their single-seeded
carpels.

FIG. 40.
SECTION OF STEM OF EXOGEN (CLEMATIS VITALBA).

X20.

[to face page 135.

VIRGIN'S BOWER 135

Virgin's Bower is the only English species,
and is so called on account of its being used
for covering bowers. It is also known as
Traveller's Joy, probably because of its being,
in winter, among the most conspicuous and
ornamental of wayside plants, often covering
hedges for a considerable distance with its
feathery seed-vessels. The flowers are greenish-
white, and, as already stated, they are destitute
of perfume.

From the feathery appearance of the seed-
vessels, resembling grey hair, the plant is
sometimes known by a third name, Old Man's
Beard.

The section shows the vine-like herbaceous
or woody stem of Clematis vitalba. Beginning
at the centre, we have the cellular tissue of
the pith ; then the fibro-vascular bundles with
air cells. Around the margin is the beautiful
structure of the cortical parenchyma.

The illustration (Fig. 40) is from a photo-
micrograph of 40 diameters ; the focal distance
was 36 inches; and the objective used was
the 1-inch.

136 PETIOLE OF NUPHAR LUTEA

Many climbing plants have sensitive tendrils
by means of which they cling to their supports,
but in the clematis, instead of separate special
organs, the clinging powers are embodied in
the long, thin stalks of the leaves themselves,
which wind round their supports.

Petiole of Nuphar Lutea.

The Nuphar lutea, or common yellow water-
lily, and the Nymphcea alba, or great white
water-lily, have the same generic characters.
The calyx consists of five or $ix leaves, the
petals are numerous and small, and there are
stamens on the seed-vessels.

These two plants are generally to be found
on lakes and ponds, in parks and gardens.
The white water-lily is found frequently in
lakes and still waters in Scotland, and the
yellow is common in most rivers and lakes.
The country people call the yellow water-lily
' Brandy-bottle,' as it smells like brandy.

The petals are usually thirteen in number,
and form a continuous spiral with the stamens.

STRUCTURE AND USES OF PLANT 13?

The Victoria regia, a Brazilian species, has
peltate leaves of more than a yard in diameter.
Both the Nuphar lutea and the Victoria regia
can effect self-fertilisation.

The fruit, which rests on the water, becoming
detached from its stalk and dehiscing from
the base upwards, effects the dissemination of
the seeds.

The section of the petiole shows the stellate
hairs at intervals. Some are transparent and
difficult to see.

The root-stocks bruised and infused in milk
are said to be destructive to cockroaches, and
when burnt to be particularly obnoxious to
crickets. The flowers are used by the Turks
in the preparation of cooling drinks, like
sherbet.

The seeds, as they contain a quantity of
starch, are used in some countries as food.
The root-stalks and flower-stalks are traversed
by a great number of air canals, the arrange-
ment of which is the same in both organs.

In the illustration (Fig. 41) the large open
ings are transverse sections of the largest inter-

138 PETIOLE OF NUPHAR LUTEA

cellular spaces bounded by simple layers of
cells. The stellate idioblasts can be seen.
The dark patches are fibro-vascular bundles.

The original photo-micrograph shows an
amplification of 20 diameters ; the focal dis-
tance was 40 inches ; and the objective was
the 2-inch.

'In the water-lily the subsequent flat leaves
are, when in the bud state, rolled together,
either each individual leaf by itself, or so that
the young leaves envelope one another. On
subsequent growth the rolled-up margins are
drawn apart and the leaves become extended
flat.

1 Now as long as the young leaves remain in
this rolled-up condition in the bud-state they
are said to be orthotropic, because they con-
stitute a radial convolute structure. But as
soon as they extend themselves they become
plagiotropic, and are placed obliquely or
horizontally with reference to gravitation and
extended at right angles with respect to the
rays of light/ (Sachs.)

FIG. 41.
TRANSVERSE SECTION OF PLANT STEM (NUPHAR LUTEA).

X 12.

[to face

CHAPTEE XIII

SPRUCE FIR, BUTCHERS' BROOM, AND
HIPPURIS VULGARIS

Spruce Fir Section.

rnHE Spruce Firs are by some botanists
-*- known as Pice a, and are a sub -genus of
the Conifera. Sometimes they are included
with the Silver Firs in Abies.

The firs are for the most part lofty trees,
with small narrow evergreen leaves placed in
two rows along the sides of the branches, or
occasionally tufted.

The cone, which is usually of a cylindrical
form, consists of a number of woody scales
which overlap each other, but are not thickened
at their points as are the scales of pine
cones.

189

140 SPRUCE FIR

This species of fir supplies fine timber trees
and yields turpentine and several substances
valued by the chemist.

The Spruce Fir so common in Norway,
Eussia, and the mountainous parts of Europe
generally, is known as Abies excelsa. It
is a handsome tree, and often rises to a
height of 150 feet. The leaves are dull green,
four-cornered, and sharply pointed. The
cones are cylindrical, with scales that are
slightly waved or toothed. These trees thrive
best on a damp soil. The timber is much used
and known as white deal. From the trunks
issues a resin commonly called frankincense,
which when melted in water and strained
constitutes Burgundy pitch.

The Silver Fir, sometimes called Abies picea,
receives its name from the fact that its leaves
are whitish on their under sides. They are
arranged in two rows, and have their points
turned upwards. The cones are erect, of a
greenish-purple colour, with scales provided
with long tapering bracts on their outer surface.
The beauty of this tree is such that Virgil has

m m

; .M /.

FIG. 42.

SPRUCE FIR, STEM SECTION,
XI5-

{To face page 140.

MICROSCOPIC STRUCTURE 141

applied to it the epithet 'pulcherrima,' 'very
beautiful.' It attains a height of 100 feet
and upwards, and is a native of Central Europe
and Northern Asia.

Its timber is not so much prized as that of
some other species, but has the great advantage
of being durable under water.

From its bark exudes a resin, which when
purified is known as ' Strassburg Turpentine.'

The illustration (Pig. 42) is taken from a
photo-micrograph of 32 diameters; the focal
distance was 32 inches; and the objective
used was the 1-inch.

It represents a section across a twig of the
Norway Spruce, Abies excelsa.

Commencing at the outside edge we see the
thick cortical cells ; next we have the cellular
tissue with air cells, or air spaces; these lie
immediately under the cortical cells; in the
third layer we observe white spaces at inter-
vals in cellular tissue, these are resin canals;
further towards the centre and radiating in
marvellously beautiful lines closely packed
together, are the woody fibrous vessels ; inside

142 BUTCHERS' BROOM

these and forming the centre of the twig are
the cells of the interior.

Butchers' Broom.

Butchers' Broom (Buscus aculeatus) is
generally found in a gravelly soil in the South
of England, where it favours woods more than
the open country. It is a handsome pltnit, and
especially so in the winter, when its bright
scarlet berries are matured.

It is prized as a Christmas decoration, and
retains its freshness longer than the holly.

It is a shrublike plant with thick white
roots, which send up a number of stems that
grow to a height of some 2 or 3 feet.

Each stem has many ovate, sharp-pointed,
dark green leaves. The flower appears on the
upper surface of the leaf. The position of the
flower and berry in the centre of the leaf
renders this plant very peculiar, and shows
another instance of the wonderful variety there
is in Nature.

Ruscus androgynus, a native of the Canaries,

FIG. 43.

SECTION OF STEM OF BUTCHERS' BROOM
X 2O.

[to face page 142.

HOW DESCRIBED BY BOTANISTS 143

bears its flowers along the edges of the leaves,
and in Buscus hypophyllum the flowers are
borne on the under side of the flattened
branches.

The young shoots of the English Butchers'
Broom are eaten like those of asparagus, and
the mature plants are made into brooms. The
plant is one of the Asparagese. Belonging
to the same sub-order are Asparagus, Lily
of the Valley, Solomon's Seal, Herb Paris,
which is poisonous, Wood Lily, and Parlour
Palm.

Recognised authorities on botanical subjects,
in a few words, express a great deal. In
Warming and Potter's Systematic Botany the
Butchers' Broom is described as follows : — ' Is a
South European shrub with leaf-like ovoid or
elliptical shoots, which are borne in the axils of
scale-like leaves, and bear flowers in the central
line. Dioecious, stamens 3, united, anthers
extrose.'

On referring to the Student's Text Book of
Botany, by S. H. Vines, I find the plant
described as follows : — ' Small shrub, with leaf-

144 HIPPURIS VULGARIS

like branches on which the declinous flowers
are borne in the axils of minute leaves.7

The photograph from which the illustration
(Fig. 43) was taken shows an amplification of
40 diameters. The focal distance was 62
inches ; the exposure 4 minutes. A yellow
screen and a Ij-inch objective were used.

Beginning at the outer margin of the section
we have the epidermal cells ; close to these we
see the bark cells; then loose cellular tissue
with air passages; all the remaining portion
consists of cellular tissue containing at intervals
the fibro-vascular bundles. The cells at the
centre are the new growth.

Hippuris vulgaris.

The Mare's-tail grows wholly or partially
submersed in ditches or canals. It sends up
from its creeping roots numerous unbranched
erect stems, having at short intervals whorls of
linear leaves. In the axils of the leaves are
small inconspicuous flowers, each of which

FIG. 44.

STEM OF SECTION OF MARE'S TAIL (HIPPURIS VULGARIS)
XI4

[ to face page 145.

OF INTEREST TO STUDENTS 145

contains a single stamen but no petals, and an
ovary with a single seed.

* There are two or three species, only one of
which is to be found in these islands. It is so
unlike any other plant, except perhaps Equise-
tum (the Horse-tail), that it is easily recognised.
The branches in the Equisetum are jointed,
while the narrow verticellate leaves are con-
tinuous throughout. There is some resemblance
in habit between the Hippuris and the
Equisetum, but in all essential characters they
are perfectly distinct. So far the plant has not
been found of any special importance in medi-
cine or the arts, but to the microscopist
sections of its stems are of great interest. The
beautiful arrangement of the multitude of cells
must always command attention and admira-
tion.' (Sachs.)

The illustration (Fig 44) is taken from a
photograph showing an amplification of 32
diameters ; the focal distance was 50 inches ;
and the objective used was the 2-inch.

Beginning at the centre of the section, we see
the pith surrounded by a cylinder of fibro-

10

146 HIPPURIS VULGARIS

vascular tissue. Outside this cylinder and close
to it are cellular tissues and air passages. Next
we have large intercellular spaces, their walls
consisting of cellular tissue. At the margin
immediately on the inside is cellular tissue,
while the external part consists of thick epider-
mal cells.

CHAPTEE XIV
HUMAN HAIR

A SINGLE human hair is by no means an
-*--*- elementary structure. It is surprising
what an amount of physiological detail it
contains. There seems to be as much care
and skill expended upon it and all its parts,
and they are many, as upon a limb or any of
the great vital organs of the body.

In its immediate composition there are nine
or ten different layers in addition to its muscles,
glands, and blood vessels. If added to all this
we were to look at a single hair histologically,
and see the various cells as they are arranged
in cuticle, shaft, Huxley's layer, Henle's layer,
and cortex of root, we should be inclined to
think we were examining a much larger and

148 HUMAN HAIR

more important matter than a single hair.
Suppose out of mere curiosity we look more
closely at some of the properties and the
composition of a hair.

First, then, the hair has considerable elas-
ticity. 'It will stretch -33 of its length. It
has great powers of cohesion, for a single
healthy hair will carry from 3 to 5 Ibs. It
will resist putrefaction for a long time. There
are many proofs of this remarkable property.
It is highly hygroscopic,' * as it readily
detects damp in the atmosphere. It is also
capable of displaying electrical effects in dry,
frosty weather. Ladies know this when brush-
ing the hair. In some of the lower animals
hairs possess an additional property; they are
feelers and real organs of touch.

1 As regards the chemical composition of
hair, it contains alkaline sulphates, calcium
sulphates, iron oxide, and salicic acid. Dark
hairs yield more iron than blonde hairs. The
black or brown colour of hair in general is due

* Text-Book of Human Physiology. Landois and Stirling.
(C. Griffin & Co.)

.

FIG. 46.

TRANSVERSK SECTION OF HUMAN SCALP.
X 100.

[to face page 149.

THE VARIOUS LAYERS 149

to melanin. There seem to be several varieties
of this pigment. Compared with the hairs of
other animals the melanin of the human hair
contains less nitrogen and more sulphur.' *

As to the physiological composition of a
single hair, we have the medulla in centre ;
this is surrounded by the cortex; next in
order is the cuticle, then Huxley's layer;
Henle's layer is next ; then we have the
external root sheath; next in order is the
homogeneous layer ; outside this the layer of
circular fibres ; and next the layer of horizontal
fibres. The three latter make up the connective
tissue portion of the hair follicle, t

We have roughly enumerated merely the main
facts connected with the component parts of a
hair ; and although we have omitted the relative
functions of all these parts, we must agree that
a hair is a most wonderful structure.

But we have not yet done justice to the hair.

* Text- Book of Human Physiology. Landois and Stirling.
(C. Griffin & Co.)

t Text-Book of Physiology. McKendrick. (J. Maclehose
& Sons.)

150 HUMAN HAIR

We should look at it from another standpoint.
'"The part projecting from the skin" is the
shaft, or scapus ; the part passing obliquely into
the skin is the root, or radix pili ; and at the
end of the root is the bulb, bulbus pili, having a
hollow underneath filled with a tissue belonging
to the corium, and termed the papilla. The
root is surrounded by a modified portion of skin
termed the follicle, in the formation of which are
found both corium and epidermis. The epider-
mal portion forms the sheath or sheaths. From
two to five glands open into the follicle, termed
sebaceous glands. A few bundles of plain,
smooth, muscular fibre pass obliquely from the
side of the follicle to the under surface of the
corium. These constitute the erector muscle
of the hair — musculus arrector pili. When
they contract towards the corium they pull on
the sheath and erect the hair.' *

The cuticle is formed of tile-shaped hard
cells, the edges of which sometimes project
from the surface of the hair. If a hair be

* Text-Book of Physiology. McKendrick. (J. Maclehose
& Sons.)

CELLULAR ARRANGEMENT 151

rolled between the finger and thumb, it will
pass along invariably in one direction, showing
that the cells are arranged to face one way.
If a hair be drawn along the lips one way and
then in the opposite direction, a difference will
readily be detected.

In the hair of certain lower animals, when
this imbricated arrangement of the cells is more
pronounced, the hairs are better adapted to the
process of felting.

On referring to the illustrations, Fig. 45
shows a vertical section of the human scalp.
Several hairs or portions of hair are seen in
situ. The original photograph is one of 26
diameters. The time of exposure was 2 minutes ;
the focal distance was 39 inches ; and the objec-
tive used was the Ij-inch without the eye-piece.
The next illustration (Fig. 46) is from a photo-
micrograph of 100 diameters. It shows the
transverse sections of several hairs, also sweat
glands and erector muscles besides several other
histological details; the focal distance was 50
inches, and the objective used was the J-inch.

CHAPTEE XV

HUMAN SKIN, HEART MUSCLE, AND
HUMAN BONE

Human Skin.

c nnHE skin consists chiefly of the exterior

*-*- epithelium, called also cuticle or epi-
dermis, and the corium, derma, or Gutis vera.

1 Below the corium are embedded several
organs with special functions, namely, the
sudoriferous glands, sebaceous glands, and
hair follicles. On the surface of the skin are
sensitive papillae.

'The so-called appendages of the skin — the
hair and nails — are special modifications of the
epidermis.

1 The epidermis j or epithelium, which covers
the true skin, is composed of several strata of

152

THE VARIOUS LAYERS 153

various shapes. Four of these layers are
distinguishable.

' First. — The Stratum corneum, which con-
sists of many layers of horny scales. The
different thickness of the epidermis in different
regions of the body is chiefly due to variations
in the thickness of this layer, e.g., on the
horny parts of the palm of the hand and
soles of the feet it is of great thickness.

6 Second. — The Stratum lucidum, a bright
homogeneous membrane, consisting of squamous
cells, closely arranged, in some of which a
nucleus can be seen.

1 Third. — The Stratum granulosum, consisting
of one layer of flattened cells, which are dis-
tinctly nucleated. A number of granules
extend from the nucleus to the margins of
the cells.

' Fourth. — The Bete mucosum, which consists
of many strata. The deeper cells are columnar
with oval nuclei, then follow several layers with
spherical nuclei. The deeper surface of the
Eete mucosum is accurately adapted to the
papillae of the true skin, being, as it were,

154 HUMAN SKIN

moulded on them. This layer is of constant
uniform thickness in all parts of the skin.
The pigment of the skin, the varying quanti-
ties of which cause the various tints observed
in different individuals and different races, is
contained in the deeper cells of the Hete
mucosum.

'It is a most remarkable fact that the
epidermis maintains its thickness in spite of
the constant wear and tear to which it is
subjected.'

How the Outer SJcin is removed.

The explanation of this is as follows : —
1 The columnar cells of the Hete mucosum
elongate, and their nuclei divide into two ;
the upper part of each cell separates from
the lower ; thus from a long-columnal cell are
produced a polyhedral and a short columnar cell.
The latter elongates and the process is repeated.

{ The polyhedral cells thus formed are pushed
up towards the free surface by the production

* Kirkes, Handbook of Physiology. Morrant Baker's
Edition. (John Murray.)

HOW THE OUTER SKIN FALLS OFF 155

of fresh ones beneath them, and become
flattened by pressure ; they also become
gradually horny by evaporation and trans-
formation of their protoplasm into keratin,
till at last by rubbing they are detached at
the surface as dry, horny scales. There is
thus a constant production of fresh cells in
the deeper layers, and a constant throwing
off of the old ones from the free surface.
When these two processes are accurately
balanced the epidermis maintains its uniform
thickness. When by intermittent pressure a
more active cell-growth is stimulated, the pro-
duction of cells exceeds their waste, and the
epidermis increases in thickness, as we see in
the horny hands of the labourer.

1 The Gutis vera. — The corium, or cortis,
which rests upon a layer of adipose or cellular
tissue of varying thickness, is a dense and
tough, but yielding and highly elastic structure.
It is composed of nbro-cellular tissue, inter-
woven in all directions, and forming by their
interlacement numerous spaces or areolae.

1 The Papilla, are conical elevations of the

156 HUMAN SKIN

corium, each with a single or divided free
extremity, more prominent or more densely set
at some parts than at others. Most abundant,
for example, on the palmar surface of the hand
and fingers and the soles of the feet, where,
therefore, the sense of touch is greatest.

* Each papilla is abundantly supplied with
blood, receiving from the vascular plexus in
the cutis one or two tiny arteries which
divide into capillary loops in its substance,
and then re-unite into a minute vein which
passes at its base.

1 The nerve terminations and many other
important points about the skin cannot be
noticed here, but it is necessary that even
a brief reference should be made to the

Functions of the Skin.

' (1) As an external integument for the
protection of deeper tissues.

' (2) As a sensitive organ in the sense of
touch.

' (3) An important excretory organ, e.g.,
perspiration, &c.

.

FIG. 47.

HUMAN SKIX, VERTICAL SECTION.
X IOO.

[to face page 156.

HEART MUSCLE 157

* (4) An absorbing organ.

1 (5) It plays an important part in the
regulation of the temperature of the body.'*

The illustration (Fig. 47) is taken from a
photo-micrograph showing an amplification of
100 diameters of the vertical section : the
focal distance was 50 inches ; and the objective
used was the j-inch.

Heart Muscle (Human).

The structure of the human heart is mar-
vellous in every microscopic detail. It must
be so in order to do the incessant and
gigantic work it does. Throughout life it
never ceases for rest, day or night. It is a
wonderful and startling thought that for 60, 70,
or even 100 years it continues its rhythmical
beats, pumping the vital fluid through the
complex human system of arteries, capillaries,
and veins. If it were to take a single half-
hour's rest we should die.

* Kirkes, Handbook of Physiology. Morrant Baker's
Edition. (John Murray.)

158 THE HUMAN HEART

In order to place before our readers a con-
crete idea of the amount of work done in a
given time by the heart, we have consulted
the calculations of seven great medical autho-
rities, and in a very brief form we append a
summary of results : —

Two of the number, after entering into
mathematical estimates, came to the conclu-
sion that the heart in one day of eight
hours does about one-quarter of the work
done by a . labouring man during the same
time, assuming that the workman works
honestly. (Dr. Waller.)

Another authority calculates the work done
per day by a horse and the work done
in the same time by the human heart, and,
omitting the details of his calculations, he
finds that the work of the heart equals ^th
that of the horse. (Dr. Hales.)

A fourth medical writer calculates that the
total work of the heart in twenty-four hours
is about 124 foot-tons. (Dr. Haughton.)

Three other medical experts agree in the
manner of ascertaining the work of the heart,

FIG. 48.

HEART MUSCLE.
X550-

[to face Page 158.

THE WORK IT DOES 159

and their results are almost identical. The
following is an outline that may bring the
matter clearly before us, while it ought to
make us value the mechanical achievements
of our hearts and the magnificence of the
structure capable of such heavy work : —

1 In estimating the amount of work done
by any machine it is usual to express it in
terms of " unit of work.'7 The "unit of
work" is defined to be the energy expended
in raising a unit of weight (1 Ib.) through
a unit of height (one foot). In England the
"unit of work" is the "foot-pound." The
work done by the heart at each contraction
can be readily found by multiplying the weight
of the blood expelled by the ventricles by the
height to which the blood rises in a tube
tied to an artery. This height has been
found to be about 9 feet in the horse, and it
has been shown that this estimate is nearly
correct for a large artery in man.

c Taking the weight of blood expelled from
the left ventricle at each systole as 4 ozs.,
that is, J Ib., we have 9 x J = 2J foot-pounds

i6o HUMAN BONE

as the work done by the left ventricle at each
systole; and adding to this the work done by
the right ventricle (about a third that of the
left) we have 2J + f = 3 foot-pounds as the
work done by the heart at each contraction.' *

In the illustration we see only an exceed-
ingly small portion of the muscular structure
of this most wonderful organ (Fig. 48). Its
fibres are visible ; they are columnar and faintly
striated; the nuclei are distinctly seen. Each
fibre is branched, and there is no covering.

The original photo-micrograph shows an
amplification of 550 diameters: the time of
exposure to gaslight was 5 minutes ; the focal
distance was 72 inches; and the objective
used was the J-inch ; the eye-piece of 5
diameters was also used.

Human Bone.

Speaking generally, bone seems to have three
distinct duties — it gives support and firmness

* Kirkes, Handbook of Physiology. Morrant Baker's
Edition. (John Murray.)

•**•*•%. »W»Jr*lTl< *1

FIG. 49.
TRANSVERSE SECTION OF HUMAN BONE.

[to face page 160.

MICROSCOPIC STRUCTURE 161

to the bodies of all members of the vertebrate
kingdom ; it protects many delicate organs ;
and it affords points of attachment for muscles.

On examining a thin transverse section of
human bone under the microscope with a
low power it is found to exhibit a number
of round or oval apertures. These are trans-
verse sections of the Haversian canals. Each
Haversian canal contains an artery, vein, nerve,
and lymphatic vessels, all for nourishing the
bone. They mostly run parallel with the axis
in long bones, but in flat bones they are
parallel to the surfaces.

Still keeping to our transverse section, but
using a higher power in the microscope, we
find it exhibits numerous dark spots with fine
lines branching from them in all directions.
The dark spots are the lacunae, and the fine
lines branching from them are the canaliculae,
or calcigerous canals. The dark appearance
of both lacunae and canaliculae is owing, in
dried bone, to the air they contain.

If the air be removed by immersion in
oil of turpentine they become white or

11

162 HUMAN BONE

transparent, according to the position of the
light.

In a transverse section of bone, the lacunae
of the layer surrounding the Haversian canals
are seen to be placed tangentially to the
orifices of these canals, whilst those of the
layer near the surfaces of the bone run paral-
lel with those surfaces.

A Haversian system, consisting of a Ha-
versian canal, its lacunae, and all the canali-
culae that communicate with that same canal,
is complete in itself, and entirely independent
of other Haversian systems.

Chemically, bone consists of gelatine with
phosphate of lime and magnesia, small quan-
tities of carbonate of lime, carbonate of mag-
nesia, fluoride of calcium, and a little oxide
of iron and magnesia.

The photo-micrograph from which the illus-
tration (Fig. 49) was taken shows an ampli-
fication of 550 diameters — the Haversian canals
appearing as large as chestnuts; the objective
used was the one-sixth, and the focal distance
was 78 inches.

FIG. 50.

SECTION OF HUMAN LUNG.
X 20.

{to face f>nge 163.

CHAPTER XVI

HUMAN LUNG, RED CORPUSCLES OF
THE BLOOD, AND HUMAN TOOTH

Human Lung.

A VEEY tiny portion of the human lung
-*-^- is shown in Fig. 50. The section is
taken transversely through a small bronchus
which appears in the illustration as the largest
of the openings. Connected with it is a mucous
gland. Sections of an artery and a vein can
be seen near the bronchus.

Four or five smaller openings, having a star-
like structure, are bronchioles (air tubes). Near
the bronchus, but lying on the side opposite
the mucous gland, are two curved, dark
objects. These are sections through two por-
tions of cartilage.

163

164 HUMAN LUNG: RED CORPUSCLES

The tiniest openings, of which many hun-
dreds are visible, are the lung alveoli, or air
cells. It is in these that the blood is aerated.
Their walls are comprised of a network of
blood vessels.

The original photo-micrograph (Fig. 50)
showed an amplification of 20 diameters ; the
focal distance was 60 inches ; and the objec-
tive used was the 3-inch.

Red Corpuscles.

Although to the naked eye the blood seems
uniformly tinted, it is found by the microscope
to be really an almost colourless fluid, con-
taining minute coloured cells which contain the
haemoglobin or red colouring matter of the
blood. Even in thin layers the blood is opaque,
on account of the different refractive powers of
the corpuscles and the plasma in which they
are suspended.

In man, and in all mammals except the
Camelidse, the form of the coloured corpuscles
is that of a bi-concave disc. In the Came-

FIG. 51.

HUMAN BLOOD.
X IOOO.

[to face page 165

'COLOURED' AND 'COLOURLESS* 165

lidae they are bi-convex and oval. There is
no nucleus observable in the red corpuscles
of the human being. There are also a few
nucleated ' white ' corpuscles which contain
no haemoglobin.

Ked and white corpuscles are now generally
known as ' coloured' and ' colourless.'

The proportion of coloured corpuscles in
health is from between 400 and 500 to one
of the colourless, but in disease there are
only about ten coloured to one of the colourless.

In the moist state the coloured corpuscles
of healthy blood form 45 per cent, by weight
of the whole mass of the blood.

In the average healthy blood there are
5,000,000 corpuscles per cubic millimetre. The
colourless corpuscles are known as leucocytes.
The coloured corpuscles of the Camelidse have
no nucleus, but in birds, fishes, and reptiles the
corpuscles are oval, bi-convex, and nucleated.

No corpuscle similar to the coloured cor-
puscle is found in the blood of invertebrate
animals, but bodies not unlike the colourless
corpuscles are seen.

166 USES OF BLOOD

Corpuscles were first seen in the blood of a
frog by Swammerdam in 1658, by Malpighi
in that of the hedgehog in 1661, and by
Leeuwenhoek in the blood of man in 1673.

Uses of Blood.

(1) < To be a medium for the reception
and storing of matter (food, drink, and oxy-
gen) from the outer world, and for its convey-
ance to all parts of the body.

(2) ' To be a source whence the various
tissues of the body may take the materials
necessary for their nutrition and maintenance,
and whence the secreting organs may take
the constituents of their various secretions.

(3) 'To be a storehouse of potential energy,
by the expenditure of which the heat of
the body may be maintained ; and by cor-
relation, vital and other force may be
manifested.

(4) ' To be a medium for the reception of
refuse matters from all the tissues, and for
their conveyance to those organs whose func-

FIG. 52.
HUMAN TOOTH, VERTICAL SECTION.

x8.

\_to face page 167.

STRUCTURE OF HUMAN TOOTH 167

>

tion it is to separate them and cast them
out of the body.

(5) l To warm and moisten all parts of the
body.' *

The illustration (Fig. 51) is taken from a
photo-micrograph showing human blood cor-
puscles amplified to 1,000 diameters. The
exposure required was 25 minutes ; the focal
length was 25 inches ; the one-sixth objective
and an eyepiece of 1 diameters were used.

Section of Human Tooth.

The vertical section of the human tooth,
roughly speaking, shows the enamel on the
crown, the dentine, the neck, the fangs, the
pulp cavity, and the Crusta petrosa, or cement
which surrounds the fangs.

The dentine constitutes the greater portion
of the substance or mass of the tooth; it
corresponds with the ivory in the tusks of
other creatures, and is whitish and of a silky

* Kirkes, Handbook of Physiology. Morrant Baker's
Edition. (John Murray.)

168 HUMAN TOOTH

lustre. It forms the entire boundary of the
pulp cavity, with the exception of a small
portion at the base of the fangs.

The dentine, or ivory, consists of a vast num-
ber of tubes or canaliculae called the ' ivory
tubes.' They are shown in the illustration as
extremely fine tubes, pursuing an undulatory
course, at first curving, then bifurcating, and
continually giving out numerous fine lateral
communicating branches.

The enamel covers the body of the crown.
It is thickest at the opposing surface, decreas-
ing towards the neck, where it terminates.
The enamel is covered by a very thin mem-
brane, which contains calcareous matter. This
can be dissolved by the action of muriatic
acid.

The enamel has a fibrous aspect, and ap-
pears of a bluish-white colour by reflected
light, and of a greyish-brown by transmitted
light. It is very brittle, and so hard as to
strike fire with steel. It consists of numerous
solid fibres, or prisms, mostly six-sided, wavy,
and transversely striped. These usually ex-

JAW OF KITTEN 169

tend throughout the thickness of the enamel
and are generally perpendicular to the surface
of the ivory they cover. The cement or bone
of the tooth does not differ structurally from
ordinary bone, excepting that it rarely contains
Haversian canals.

The photo-micrograph from which the illus-
tration (Fig. 52) was taken shows an ampli-
fication of 15 diameters ; the focal distance
was 50 inches; and the f-inch objective was
used.

In the next illustration (Fig. 53) we have
represented a vertical section through the jaw
of a kitten. This shows the positions of both
the ' milk ' and the ' permanent ' teeth.

The photograph shows an amplification of
26 diameters ; the focal distance was 84
inches ; the time of exposure to gaslight was
10 minutes; and the objective used was the
3j-inch.

CHAPTER XVII

PARASITES OF IGUANA, BUFFALO,
SHEEP, AND BEE; THE CHEESE MITE

Ixodes.

PEAKING generally, the enthusiastic stu-
dent of the microscope rarely objects to
study any insect or other creature that to the
ordinary observer appears unattractive, or even
objectionable. He is sure to find something
of an attractive or interesting character in
some part of its structure or history — e.g., the
scales on its wings, the complex arrangement
of its eyes, its breathing apparatus, its mouth
appendages, &c.

But frequently, beyond all these fascinating
materials of study, he has higher aims in view.
He is in the pursuit of knowledge. There is

170

FIG. 53-

KITTEN'S JAW. VERTICAL SECTION SHEWING THE "MILK
TOOTH BEING DISPLACED BY THE PERMANENT TOOTH.

X 12.

aer page 169.

[to face page 170

VALUE OF RESEARCH 171

some epidemic or some disease, the causes
of which are only surmised. The parasites,
germs, bacilli, suspected, have to undergo
rigorous examination, so that their whole de-
velopment may be made known, and the cause
of the disease or other trouble ascertained.

Pasteur with his microscope was able to
save the vintage and the silk industries of
the Continent. Owing to the microscopic study
of parasites, bacilli, &c., our medical men
are gradually becoming more skilled in their
methods of conquering some diseases, in pre-
venting others, and in rendering some of them
less dangerous to human life.

Malarial fever, now known as being chiefly
caused by the mosquito — Anopheles — as noticed
in another chapter, is a case in point.

Miss Ormerod, armed with her microscope,
helped the farmers by showing to them the
life-history and habits of the insect-enemies of
their crops.

Certain insects may be objectionable in ap-
pearance and habits, but their history, mode
of development, &c., must be known before we

172 IXOPES

can be prepared to stop their ravages or the
results directly or indirectly arising out of
their existence. This age in which we live
will be referred to in history as the age
in which this special line of research was
initiated.

At the meeting of the British Association
recently held it was conclusively shown that
the disastrous plague is spread throughout
India by the agency of a parasite.

We have four creatures to notice, which
cannot be recommended for any apparent
beauty they may possess. If they have ele-
ments of beauty, it is probable these are only
recognised and fully appreciated by their own
species.

They differ from insects in general chiefly
in that they possess eight legs instead of six ;
the thorax also is fused with the abdomen,
while the abdomen is not divided into segments.

The mouth -appendages are adapted for
piercing, sucking, or biting.

A very wonderful tracheal system is usually
present.

STRUCTURE AND HABITS 173

The four pairs of legs are segmated and
usually end in claws, but these may be replaced
by a sucking-disc.

The claws are wonderfully adapted for cling-
ing round the hairs of animals upon which
they may be living as ectoparasites.

The creatures are classed with the Acarinai
and are looked upon as ticks.

It is thought that originally they were
vegetable feeders. Even now they feed on
vegetable matter, but are ever ready to attach
themselves to animals and to perforate the
skin with their saw-edged trunks. Cattle and
snakes are their chief victims.

They are greedy creatures, and will suck
blood to such an extent that their bodies
sometimes swell to the size of a small walnut.

They have a large plate on each side of
the ventral part of the body, which may act
as a sucker of attachment, or it may do similar
duty to that of the spiracle of the water
beetle, noticed in another chapter.

This sucker-plate forms a very beautiful
object for the microscope.

174 THE H^EMATOPINUS

Ixodes of Iguana.

The first of these is Ixodes, an external
parasite on the lizard Iguana.

The illustration (Fig. 54) is from a photo-
micrograph of 30 diameters ; the focal distance
was 30 inches ; and the objective used was the
1-inch.

The Hsematopinus.

This creature is the parasite of the buffalo,
and it belongs to the sub-order Parasitica.

It is devoid of wings, and dwells on the
skin of the buffalo, sucking its blood.

The proboscis is fleshy and unjointed ; there
are two simple eyes ; the antennae have five
joints; the legs arise from the edge of the
pro-thorax, and they terminate in a hooked
claw. This forms an admirable apparatus for
clinging on to the hairs of their hosts. The
young do not undergo any metamorphosis.

The illustration (Fig. 55) is from a photo-
micrograph of 40 diameters; the time of ex-
posure to gaslight was two minutes; the focal

FIG. 55.

H^EMATOPINUS OF BUFFALO.
X25.

[to face page 174.

THE SHEEP TICK i?5

distance was 27 inches; and the objective
used was the inch and a half.

The Sheep Tick.

The zoological name of the Sheep Tick is
Melophagus ovimus. It belongs to a division
of the Diptera, or two-winged insects, known
as the Hippoboscidce. The wings are variable,
sometimes present and large, sometimes mere
strips.

In the same group with the Sheep Ticks
are the Forest-fly, the Horse-fly, &c.

The proboscis is of peculiar formation, and
is not like that of other flies. It consists of
two elongate, closely - adapted hard flaps,
capable of diverging laterally to allow of an
inner tube to be passed out from the head.

The Sheep Tick seems to be specially
adapted for creeping about on the skin of the
sheep beneath the wool.

Its life-history is not fully known. The
creature, unlike most other insects, lays but one
egg at a time, which becomes hard externally.

176 BRAULA CiECA

The larva from the egg has no true head.
Its tracheal system is also peculiar.

The illustration (Fig. 56) is taken from a
photo-micrograph of 32 diameters ; the time
of exposure was one minute; the focal dis-
tance was 64 inches; and the objective used
was the 2-inch.

Braula Caeca.

Notwithstanding its name, this insect is not
blind. Its eyes are not so highly organised
as are those of many other insects, but it can
see over short distances, and that is all it
requires.

It lives as a parasite on the honey-bee, and
is of necessity an exceedingly small creature,
Lucas says that it specially affects the thorax
of the bee. Miiggenburg believes it pays
special attention to the queen bee, because of
the exposed membranes between the segments
of the body.

Boise, another observer, says that the
creature, not content with living on the bee,

FIG. 56.

SHEEP TICK.

XI4.

[to face page 177.

THE CHEESE MITE 177

deposits a pupa in the cell beside the young
larva of the bee, and that the young Braula
appears as a perfect insect in 21 days.

It is Packard's opinion that on the day the
larva hatches from the egg it sheds its skin
and turns to an oval puparium of a dark
brown colour.

By comparing the antennae with those of
the sheep tick a resemblance will be noticed,
though they are not so completely concealed
in their cavities.

In the original photo-micrograph this para-
site is (Fig. 57) shown with an amplitude of
220 diameters; the focal length required was
66 inches; an eye-piece of 5 diameters and
a 1-inch objective were used.

The Cheese Mite.

The name by which this creature is now
known is TyroglypTius siro. The creature is
classed with Ixodes, and therefore belorigs to
the Acarina. It has a peculiarly-shaped pro-
boscis in the form of a cone. It possesses

12

i?8 THE CHEESE MITE

four pairs of legs, which are five-jointed and
have lobes for attachment and claws. Large
suckers, especially in the male, are located
near the posterior end of the body. The
snout appears to do the duty of mandibles.

The powder of old, dry cheese consists
almost entirely of mites and their eggs. The
eggs are hatched in about eight days.

The illustration (Fig. 58) is taken from a
photo-micrograph of 250 diameters ; the focal
distance was 75 inches; an eye-piece of 5
diameters and a 1-inch objective were used.

FIG. 57.

PARASITE OF BEE.
X 100.

[ 7'ff /ace page 178.

CHAPTEB XVIII

4

^

A WATER-MITE. (Mideopsis orbicularis.)
SPIDER'S FOOT AND WOLF SPIDER

A Water-Mite.

(Mideopsis orbicularis.)

E tiny Water-mite (Fig. 59) is a new
discovery, and has recently been shown
at the Quekett Club by Mr. Henry Tavener,
the discoverer. It will be sure to interest those
who study pond-life. Its body is almost a true
circle. Each of the eight legs consists of five
segments, the hairs of which point backwards.
The object is an exceedingly beautiful one under
the microscope.

The original photo-micrograph shows the
creature as if amplified to 90 diameters; the
focal distance was 75 inches ; and the objective
used was the 1-inch.

180 SPIDER'S FOOT

Spider's Foot.

The Spider's foot always excites the admira-
tion of every one who watches it attentively
as it is employed by the spider in its many
operations.

It is constructed upon a very curious plan,
and is evidently adapted for a variety of duties,
reminding one of the American tool that can
be utilised for six or seven other tools as
necessity arises. But its chief functions appear
to be connected with those of the spinnerets,
when it renders admirable service in 'rope-
drawing ' and guiding.

The foot has three strong, horny claws; on
the largest of these there are eighteen teeth like
those of a comb, while fifteen appear on the
next claw and three or four on the smallest.
These are quite distinctly seen on the original
photographic plate. Doubtless with this appa-
ratus the spider can regulate the rate of issue
of the filaments as they proceed from the spin-
nerets. The use of the word c spinneret ' is
unfortunate, as the spider does not spin.

see page 177.

FIG. 58.
CHEESE MITE.

x 125.

[to face page 180.

THE SPIDER'S TELEGRAPHY 181

By its feet it can suspend itself on its
almost invisible thread. The comb-claws are
frequently used for cleansing purposes, in much
the same way as the house-fly uses its feet.

That the creature possesses some kind of
telephonic or telegraphic power is evident to
any close observer of the ways of the garden
spider. Whatever the nature of the power may
be, it is certain that the Spider can, when quite
out of sight in a remote end of its home, locate
the exact position of a fly on the web. Dr.
Dallinger and other writers attribute this power
to the exquisite sensitiveness of the spider's
feet. * By resting these upon a trap-line of
silk carried to her den she can, by a veritable
telegraphy, discover instantly, not only the fact
that there is prey upon her snare, but the exact
spot in the web of the snare in which that prey
is entangled. In the same way by seizing
certain tautened threads communicating with
the main lines of the snare, she can discover in
an instant the presence and position of her
prey, though far beyond the reach of vision.'
A veritable and wonderful system of telegraphy

182 SPIDER'S FOOT

indeed, and all contained within very limited
dimensions ! This is another instance of
modern science anticipated by one of Nature's
tiny creatures.

Spiders not only have done this, but they also
aid science very materially owing to the extreme
fineness of their silken threads. The astrono-
mer encourages the spider for the sake of its
web, the strands of which are finer than any
other substance he has access to, and are used
for micrometer lines in the eye-pieces of his
telescopes.

The Garden Spider displays great ingenuity in
the protection of its web on windy days. The
writer's attention was drawn one stormy day to
a large web at the end of the garden. It was
stretched from a cabbage to the paling ; it was
a frail-looking structure, and apparently was not
strong enough to last long in such weather.
Still, it withstood the storm, and this is where
the spider's instinct rose to the occasion. A
long thread of silk depended from the centre
of the web and hung down a considerable
distance below. To the end of this thread was

FIG. 60.

SPIDER'S FOOT AND PART OF LEG.

X 1 2s.

[to face page 183.

STRUCTURE OF WEB 183

attached a ball of clay about the size of a
small marble. The clay ball was literally
wrapped up in web material. Its use was
obvious. When the web was blown one way
the plumb pulled in the opposite direction, and
so the snare was kept comparatively steady.
It was a success — it withstood the storm !

Blackwall, the great authority of the past
generation on spiders, states that two different
kinds of materials are used in the construction
of their nets. The boundary lines, the radii
and the first-formed spirals are unadhesive, and
possess only a moderate share of elasticity ; they
are evidently composed of a different material
from that used in making the spiral line which
completes the web, which is exceedingly viscid
and elastic in a remarkable degree. The
viscidity of the spiral thread may be shown
to depend entirely upon the presence of a series
of globules, resembling tiny beads ; if these
be removed, a fine glossy line is left which is
highly elastic but perfectly unadhesive.

Dr. Dallinger tells us that these beads, or
globules, are produced after the thread is drawn

184 THE WOLF SPIDER

out, by a special vibratory action set up in the
thread by the spider !

The original photo-micrograph (Fig. 60)
shows this foot amplified to 260 diameters.
The approximate focal length was 37 inches ;
an eye-piece of 7 diameters, and a 1-inch
objective were used.

At the request of the editor of Knowledge
this appeared in a whole-plate illustration in
the July number of that magazine, 1904.

The Wolf Spider.

(Lycosa.)

The Wolf Spiders usually pursue their prey
by running after them, hence their name.
There are some spiders that do not seem to be
able to run, but are good jumpers. Of these
Salticus tardigradus and Pelenes tripunctatus
are English examples. The former are usually
found in park overlapping palings, the latter
at the base of the underclifis near the seashore.
The Wolf Spiders are numerous, and are found
near most woods in England.

FIG. 6l.
WOLF SPIDER.

\to face page 184.

SPIDERS' NESTS, ETC. 185

They have eight eyes arranged in transverse
rows. Their legs are long and hairy. The
female carries the egg-pouch about with her,
attached to the end of her body till the young
are hatched, when they climb on her back. To
this family belongs the famous spider Lycosa
tarentula (Linn.). Its bite was supposed in
Italy to bring on a fit of melancholia that
could only be cured by the tune known as the
Tarantella.

The nests of some of these spiders are hardly
less curious than are those of the Trap-door
Spiders. Of these a North American species,
Lycosa arenicola (Scudder), makes a structure
resembling a huge bird's-nest or small turret
over the entrance to the tube. Some of the
Lycosidae frequent water and are able to pursue
their prey on it or in it. The Dolomodes fim-
briatus (Clerck) actually constructs a small
raft, on which it sails about.

Connected with the life-history of the Lycosa
is an interesting insect, the Mantispa. In the
spring, when these spiders have formed their

bags of eggs, the minute larvae of the Mantispa

12*

186 THE WOLF SPIDER

find them out, tear a hole in the bag, and enter
among the eggs ; here they wait until the eggs
have attained a fitting stage of development
before they commence to feed. Brauer found
that they ate the spiders when these were quite
young, then they changed their skin for the
second time and also underwent a great change
of form.

The newly - habilitated Mantispa spins a
cocoon in the interior of the egg-bag of the
spider, and changes to a nymph inside the
larva-skin. Finally the nymph breaks through
the barriers, larva-skin, cocoon, and egg-bag of
spider, by which it is enclosed, and appears
shortly afterwards as a perfect Mantispa. The
mother spider, although watching over the
development of her eggs, seems to be uncon-
scious of the havoc that is going on among her
young.

The illustration (Fig. 61) is taken from a
photo-micrograph showing the creature as if
amplified up to 18 diameters ; the focal distance
was 36 inches ; and the objective used was the
2-inch.

FIG. 62.

TETANUS (LOCKJAW) BACILLI.
x i, coo.

\to face page 187,

CHAPTEE XIX

TETANUS (LOCKJAW) BACILLI ; SCALES
OF THE SOLE

WHATEVER else there may be of
importance or otherwise in these
chapters, there can be no doubt as to the
interest of the discovery made quite recently
by a medical friend. The extremely useful
purposes to which photo-micrography can be
applied have rarely met with a better illus-
tration.

The doctor was called to see a child
seriously ill, and he diagnosed the trouble
as tetanus in its most virulent form. As a
result of a strict investigation as to its cause
the fuller's earth used by the nurse came
under suspicion, especially as tetanus bacilli

1ST

188 TETANUS BACILLI

are found in most samples of cultivated
soil. He took it away. He had cultivations
made by inoculating a nutrient glucose broth
(peptonised juices of meat with sugar) with
a portion of the fuller's earth, thus enabling
any bacilli present to germinate. The tube
containing the inoculation was then kept in
water at a temperature of 80° C. for ten
minutes, when all non-sporulating organisms
were killed off. This was then incubated for
forty-eight hours in another tube (Buchner's),
with a bulb at the lower end filled with equal
quantities of strong pyrogallic acid and a
20 per cent, solution of KOH (caustic potash),
so that all free oxygen was absorbed; oxygen
being inhibitory to the growth of the tetanus
bacilli.

A specimen from the culture so obtained
was mounted in the ordinary way and stained
with fuchsin. Under the -^ih oil immersion
lens bacilli were discovered. The bacilli of
tetanus are immobile, and from their shape
they are termed 'drumstick.' The illustration
(Fig. 62) shows several specimens of this shape.

SCALES OF THE SOLE 189

This discovery concerns alike doctors, nurses,
and parents. The mortality among infants
is enormous, and is commented upon almost
daily in our papers. Here, apparently, . is
one cause of at least one of the fatal
diseases. Fuller's earth must be abandoned
altogether as a dressing for open wounds, how-
ever produced, or its sale in an unsterilised
form be prohibited.

The illustration is from a photo-micrograph,
showing the ' drumstick7 bacilli amplified
to 1,000 diameters. As already stated, the
objective used was a T^th oil immersion.

Scales of the Sole.

The imbricated arrangement of the scales
covering the skin of the sole makes this fish
of more than ordinary interest to students with
a microscope. The illustration (Fig. 63) is
from a negative of 36 diameters.

CHAPTEK XX
CIRCLET OF SCOLEX ; SILK

The Circlet of Scolex.

beautiful object is scarcely visible to
unaided eyesight, both because of its
minuteness and of its transparency. In the
original photo-micrograph it looks like a
piece of sculptured marble. Three questions
naturally arise in connection with this
curious object. First, is the circlet arranged
artificially ? What are its uses ? And what
is a scolex?

The circlet occupies this form in Nature,
and is arranged around the head of a tiny
creature. Its mission is to hook on to
certain internal parts of creatures on which

190

SCALES ON SKIN OF A SOLE.

x 30.

S to face page 190.

CIRCLET OF SCOLEX 191

it subsists, and in which it undergoes develop-
ment into a more advanced stage of life.

Finally, what is a Scolex? Only medical
students will be interested in the answer.

Professor Siebold long suspected that the
ring of horny spines forming the armature of
the Cysticercus fasciolaris met with in the
liver of the mouse, and a similar structure in
Tcenia crassicollis, found in the cat, strongly
resembled each other, and at length, by
experiments which we need not describe,
ascertained beyond the possibility of a doubt
that they are identically the same.

Kuchenmeister also found by experiments
with animals that C&nurus cerebralis and
Cysticercus cellulosa are but Scoleces in the
ordinary chain of life of the tape-worm.

Van Beneden's researches led to the same
result.

We may feel somewhat squeamish about
the mention of Entozoa, but it is better to
know something of the life-history of these
internal enemies of the human being, and
benefit by the knowledge, than to remain in

IQ2 SILK

ignorance and eat certain foods, or food
insufficiently cooked, thereby incurring dis-
tressing consequences.

The scolex, then, is but one stage in the
life of a Taenia. The Cysticercus is another,
equivalent to the larval condition. In this
form it occurs in the cellular tissue of the
pig, and produces the disorder known as
1 measly pork.' It is also found in the ape,
dog, ox, rat, &c.

When in large numbers, as in the Csenurus
stage, it appears in the brain of the sheep,
and causes the disorder known as 'staggers.'

A long account of this uninviting subject is
to be found in Rymer Jones's Animal Kingdom.

The original photo-micrograph (Fig. 64)
shows an amplification of 550 diameters; the
focal distance was 50 inches; an eye-piece of
5 diameters, and a J-inch objective were used.

Silk.

It is not necessary to say much about
silk. Every one knows how it is produced,

,

FIG. 64.

CIRCLET OF HOOKS ON A SCOLEX.
X IS0-

[ To face page 19.

SILK 193

and the life-history of the moth is also
well known. But a portion of manufactured
silk is here shown to illustrate the coarse
workmanship which the workman considers
fine. The amplification is only a fraction of
that which some of the objects described in
other chapters have undergone. If it had
been magnified on the same scale as any of
the diatoms, it would have appeared as coarse
as a door-mat. Search where we may among
the finest art treasures, the costliest minia-
tures on ivory, the finest linen, or anything
else that displays man's highest skill and
most artistic taste, and all will appear rough
and uneven under the microscope. This
portion of silk (Fig. 65) was, in the first
instance, photographed through the micro-
scope and amplified to 50 diameters ; the
focal distance was 50 inches ; and the
objective used was the 1-inch. The object
being opaque reflected light was required ;
hence the exposure (15 minutes) was long.

The piece of silk selected was not coarse
as compared with other silks. This contrast

13

194 IMPERFECTION OF MAN'S WORK

between man's most tasteful work and that
of the humble things of Nature ought to
impress us more than it does. It is humi-
liating, in a sense, that if we amplify man's
work its deficiencies and imperfections increase
with the amplifying process, but the opposite
occurs with Nature's works. The more we
enlarge the microscopic natural history object
the more wonderful it appears.

The microscope and the camera used either
singly or as a combined instrument aid us in
forming some faint conception of the beauty
of this material world — fallen as it is — and
yet so fair and so full of the Creator's
wisdom.

THE END.

FIG. 65.

FINE SILK.

X5°-

[to face page 194.

INDEX

ABIES, 4, 138, 140
Actinocyclus Ralfsii, 110
jEgilops, 113
Anopheles, 91, 171
Ant- Lion, 93

Antenna of Melolontha, 100
Anthomyiidae, 77
Apis mellifica, 85, 87
Aristolochia gigas, 126

BARNACLE, CIRRI OP, 63
Bee, Leg of Honey, 87

„ Tongue of Honey, 85
Bergmehl, 106
Blackwall, 183
Bone, Human, 160
Braula caeca, 176
Burmeister, 101
Butchers' Broom, 142
Butterfly's Tongue, 79

CALAMUS ROTANG, 129
Canaliculae, 161, 168

Carpathians, 53
Cirri of Barnacle, 63
Clematis vitalba, 134
Claus, 84
Cockchafer, 100
Cole, Martin J., 49
Corpuscles, Bed, 164
Coscinodiscus bi-angulatus,

111

Crane Fly, 98
Culex pipiens, 92
Cutis vera, 152
Cysticercus, 192

DADDY-LONG-LEGS, 98

Developer, 40

Diatoms, 103

Dodder on Clover, 117

Dog's Bay, Ireland, 54

Dolomedes fimbriatus, 185

Dragon-Fly, 70

Dufour, 96

Dytiscus marginalis, 82

195

196

INDEX

ECHINI, SPINES OP, 65
Egyptian Pyramids, 53

FABBB, M., 113
Foot-pounds, 159
Foraminifera, 50
Fuller's Earth, 187

H-EJMATOPINUS, 174

Hair, Human, 147
Haliotis, Badula of, 60
Haversian Canals, 161
Heliopelta, 110
Henle's Layer, 147
Hicks, Dr., 101
Hippuris vulgaris, 144
Hogg, Dr. Jabez, 86
Hooker, Dr., 130
House Fly (Muscadomestica),
75,78

ISOCHROMATIC PLATES, 41

Ixodes, 170

JONES, PROP. EYMER, 71, 82

KINGSLEY, CHARLES, 17

LACUNA, 161

La Place, 32

Law of Restriction, 70, 71

Leeuwenhoek, 166

Lily, Bud of, 133

Limpet, Badula of, 61

Lockjaw, 187
Lung, Human, 162
Lycosa, 184

MANTISPA, 185
Mare's-Tail, 144
Melolontha, Antenna of, 100
Mideopsis orbicularis, 179
Miliolida, 53
Mite, Cheese, 177
Moore, T., 113
Mosquito, 90
Muscidae, 75
Muscle of Heart, 157
Myrmeleon, 93

NAVICULA LYRA, 110
Nelson, E. M., 35, 109
Nettle Sting, 123
Nicobar Islands, 47
Nummulitic Limestone, 53
Nuphar lutea, 136
Nymphoaa alba, 136

ODONTOPHORE, 58, 61
Old-man's-beard, 135
Ormerod, Miss, 171

PATELLA VULQATA, 61

Pedicellariae, 67

Pelenes tripunctatus, 184

Petiole of Nuphar lutea, 136

Plancus, 54

Pleurosigma angulatum, 34

INDEX

197

Polycystina, 44
Proboscis of Blow Fly, 72
Proboscis of Butterfly, 79

EADULA OP LIMPET, 59, 60
of Whelk, 60

Eete mucosum, 153

Khyngia, 97

Buscus aculeatus, 142
,, androgynus, 142
„ hydrophyllum, 143

SCOLEX, CIRCLET OP HOOKS

ON A, 191
Silk, 192
Skin, Human, vert, sect.,

152

Spider's Foot, 180
Smith, Worthington G., 122
Sole, Scales of the, 189
Spruce Fir, 139
Stag Beetle, 71

Stratum corneum, 153
„ granulosum, 153
,, lucidum, 153

Swammerdam, 166

TETANUS BACILLI, 187
Tick, Sheep, 175
Tipula, 98
Tooth, Human, 167
Triceratium favus, 111
Triticum, 112

URTICA DIOICA, 124

VICTORIA LAND, 105

regia, 137

Virgin's Bower, 134

WATER LILY, 136
Wheat Stem, 112
Whelk, Eadula of, 60
Wolf-Spider, 184
Wolle, Rev. F., 107

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Assistant at the Observatory.
With many Illustrations from Original Photographs.

Large crown 8vo. Cloth gilt, gilt edges. 53.
'The scientific work carried on at the Observatory is lucidly described.'—

' An excellent popular book of science.'— Daily News,

-LM.I • ATxauAiu^x. 0 a-ii<ji.iwgi djjii n<td All llic iaaullUlLlull win*

even for those who understand nothing about it/ — Academy,

The Midnight Sky.

Familiar Notes on the Stars and Planets.

By EDWIN DUNKIN, F.R.S., F.R.A.S.,

Fast President of the Royal Astronomical Society, late Chief Assistant

at the Royal Observatory, Greenwich.

With 32 Star Maps and numerous other Illustrations.

New and thoroughly Revised Edition, with an additional Chapter

and many New Engravings.
Imperial 8vo. Cloth, gilt top. 8s.

' Those little Maps of the starry spaces far surpass, in clearness and useful worth,
ftD I have seen before in the planisphere way ; no reader but by help of them may
find, with a minimum of trouble, the star he seeks. . . . Why did not somebody
teach me the constellations too, and make me at home in the starry heavens, which
are always overhead, and which I don't half know to this day ? '—THOMAS CARLYLB
(referring to the first edition of this book).

* For a study of the constellations nothing can be simpler than the system which
Mr. Dunkin has adopted. One especially interesting chapter in the present volume
is entirely new. It is an account of the principal observatories of the world, bat
especially of Greenwich Observatory, where for so many years Mr. Dunkin was chief
assistant.' — School Board Chronicle.

' For any one who desires to study the face of the sky we can imagine no bettef
present than this very handsome volume.'— Yorkshire Daily Post.

LONDON: THE RELIGIOUS TRACT SOCIETY.

The Honey Bee :

Its Nature, Homes, and Products.

By W. H. HARRIS, B.A., B.Sc.

With Eighty-two Illustrations. Crown 8vo. Cloth gilt. 2s. 6d.

' Contains a comprehensive and lucid account of its subject, written in an in-
teresting style, and accompanied by numerous woodcut illustrations. No aspect of
the subject, whether historical, scientific, or practical, appears to have been neglected
by the author.'— Naturalist.

Ants and their Ways.

By the Rev. W. FARREN WHITE, M.A.

With numerous Illustrations, and a Complete List of Genera and
Species of the British Ants.

Crown 8vo. Cloth gilt. 2s. 6d.

' Will be of great assistance to any entomologist wishing to commence the study of
our native ants ; while as an interesting volume for the general reader, and as a
gift -book for young people with a taste for natural history, it may be recommended
as among the very best of its kind.' — Nature.

Modern Ideas of Evolution as Related
to Revelation and Science.

BySiRj.W.DAWSON, C.M.G., LL.D., F.R.S.,

Author of « The Chain of Life in Geological Time ; ' ' Egypt and
Syria : their Physical Features in relation to Bible History,' etc.

Sixth Edition. Revised and Enlarged.
Crown 8vo. Cloth gilt. 33. 6d.

•It embodies the thoughts of an eminent geologist on some of the chief flaws and
discrepancies in what he justly styles the " hypothesis " of evolution. If there is
anything calculated to arrest the cocksure young scientist, who is always the young
man in a hurry, this book will do it. Perhaps nothing but a counterblast — and Sir
William Dawson's book is too well reasoned to deserve the term — can be expected to
shake the unfaltering confidence of the middlemen of science, who purvey Darwinism,
or what they consider to be Darwinism, to the intelligent multitude.' — Saturday
Review.

The Meeting Place of Geology and
History.

By SIR J. W. DAWSON, C.M.G., LL.D., F.R.S.,

Author of ' Modern Ideas of Evolution as related to Revelation and

Science.'
With Illustrations. Crown 8vo. Cloth gilt. 55.

1 A popular exposition by a competent authority of the results of recent researches
in the debatable ground intervening between the later part of the geological record
and the beginnings of sacred and secular history.' — Times.

LONDON : THE RELIGIOUS TRACT SOCIETY

BISHOP HANNINGTON

And the Story of the Uganda Mission.

Prepared by W. GRINTON BERRY. M.A.
With Map, Portrait, 3 Coloured and 4 other Illustrations, crown 8vo,

cloth gilt, Coloured Medallion on Cover, Is. 6d.
The personality of Hannington was full of colour and vigour, and
the story of his work, particularly of his adventures in East Africa,
ending with his martyrdom on the shores of the Victoria Nyanza, is
cne of the most fascinating in missionary annals. Hannington was
himself a picturesque writer, with a noteworthy gift of producing
dashing and humorous descriptive sketches, and quite a third of the
present volume consists of Hannington's own narratives. This volume
will serve to sustain and deepen the perennial interest in Uganda,
where the Gospel has won some of its most glorious triumphs.

ALFRED SAKER

The Pioneer of the Cameroons.

By his Daughter, E. M. SAKER.

With Map, 3 Coloured and other Illustrations, Coloured Medallion
on Cover, crown 8vo, cloth gilt, Is. 6d.

The Cameroons are a little known land, but they have been the
scene of some of the most interesting work done by British mission-
aries on the West Coast of Africa. The land, like Sierra Leone, long
justified the title of "The white man's grave." The people were
savages, amongst whom it was not easy to work. The language was
new, and Alfred Saker gave his life to this field. The story of his
adventures and encouragements is singularly interesting.

A DOCTOR AND HIS DOG IN UGANDA

From Letters and Journals of A. R. Cook, M.D.

Medical Missionary of the Church Missionary Society.

Edited by Mrs. H. B. COOK.

With a Preface by EUGENE STOCK. Second Impression. With Photo-
graph, Map of Uganda, and 12 other Illustrations, crown 8vo,
cloth gilt, 2s.

" With sincere pleasure I commend this little book. A great deal
has been published from time to time on Uganda and the Uganda
Mission, but this is the first book recounting the experiences of a
Medical Missionary. To one who remembers the past history it is
wonderful to read a book like the present." — Eugene Stock.

"This little book will be of interest to people other than those
actively engaged in mission work, for the social and economic con-
ditions of the country are by no means lost sight of." — Manchester
Courier.

" We know of no other book which gives so vivid and realistic a
picture of the daily life of the missionaries of Uganda." — Record.

LONDON: THE RELIGIOUS TRACT SOCIETY.

JAMES CHALMERS

His Autobiography and Letters.

By the late RICHARD LOVETT, M.A.,
Author of "James Gilmour of Mongolia," etc.

Seventh Impression. With 2 Maps and 8 Portrait Illustrations,
511 pages. Large crown 8vo, cloth gilt, 3s. 6d. In padded
paste grain, round corners, gilt edges, 6s. 6d. net.

" Altogether no brighter or more skilful narrative of missionary life
— from the subjective as well as from the objective point of view — has
ever been published than this." — The Spectator.

" It is the best missionary biography that has appeared during the
last twenty years. It is a book that will live and take rank as a mission-
ary classic. It is full of thrills, tremulous with .pathos, glowing in its
passion, and sublime in its tragic ending. A book to be read and
re-read when the enthusiasm of humanity wanes, and we are tempted
to let fireside heroics take the place of action." — The Daily News.

GRIFFITH JOHN

The Story of Fifty Years in China.

By R. WARDLAW THOMPSpN, D.D.
(Foreign Secretary of the London Missionary Society).

Fifth Impression. With Two Maps and Sixteen other full-page Illus-
trations. Demy 8vo, cloth gilt, 568 pages, 3s. 6d.

"No one can read this story without being inwardly refreshed.
The mere adventure side of it is stirring to a degree. It reveals a
Pauline daring and endurance." — Christian World.

"The story of Dr. John's life is a very fascinating one, and it is told
by Dr. Wardlaw Thompson with much literary skill, and excellent
taste and judgment." — The Westminster Gazette.

W. HOLMAN BENTLEY

The Life and Labours of a Congo Pioneer.

By his Widow, H. M. BENTLEY.

With a Photogravure Portrait, Map, and 19 other Illustrations,
466 pages, demy 8vo, cloth gilt, 6s. net (by post, 6s. 5d.).

"This highly interesting memoir forms a worthy tribute to the
honourable life and devoted labours of a notable pioneer of Christianity
in Darkest Africa, who gave twenty-seven years to missionary work
upon the Congo. . . . The book forms an admirably interesting life-
story of successful mission work." — The Standard.

" Important in itself as the record of a notable, heroic and con-
secrated life, important also in the influence which it is sure to have
on scores of young men and women in our Churches." — The Baptist
Times.

LONDON : THE RELIGIOUS TRACT SOCIETY.

THE BAG AN DA AT HOME

With one hundred pictures of life and work in Uganda.

By C. W. HATTERSLEY.

80 full-page Illustrations, demy 8vo, cloth gilt, 5s. net.
Mr. Hattersley knows more about Uganda and its people than any
author who is just now before the public. Would you know the
difference between the Uganda of Mtesa or the Uganda of King Daudi ;
or how the British administer Uganda ; or how the Baganda live
from day to day ; or how the missionaries have given the people a
system of education ; or how they marry in Uganda ; or how the
sleeping-sickness is slaying its thousands ; or how the Gospel has won
some of the most striking results in the history of Christendom ?
Then this book will tell you.

UGANDA BY PEN AND CAMERA

By C. W. HATTERSLEY.

Second Impression. With a Preface by T. F. VICTOR BUXTON, 34
Illustrations, large crown 8vo, cloth gilt, 2s.

" The narrative is a vivid and soul-stirring record of one of the most
remarkable movements in the annals of missionary enterprise." —
Christian.

" Mr. Hattersley's book is full of interesting details, from which one
may get a clear idea of the country and its people." — Spectator.

AMONG THE TIBETANS

By ISABELLA L. BISHOP, F.R.G.S.,

Author of " Unbeaten Tracks in Japan," etc.
With 22 Illustrations, crown 8vo, cloth, Is. 6d. ; also in paper cover, Is.

"This is one of the brightest, most life-like, and most perfectly
balanced of Mrs. Bishop's works." — Spectator.

"A delightful book of travel, characterised by all the distinguished
writer's purity of style, vividness of description, and attention to
detail, which make her books so interesting and useful." — Record.

THE CROSS IN THE LAND OF THE

TRIDEN"".
Or, India from a Missionary Point of View.

By HARLAN P. BEACH.
Crown 8vo, cloth, Is.

" The trident, the three-pronged fork, which appears in every Siva
temple in India, has come to be regarded as the symbol of the Hindu
religion. This little book deals with missionary work in India, but is
in no sense a narrative. It, however, contains much matter which
will prove attractive to ordinary readers." — English Churchman.

LONDON : THE RELIGIOUS TRACT SOCIETY.

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