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Full text of "The world of life; a manifestation of creative power, directive mind and ultimate purpose"

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THE WORLD OF LIFE 



THE WORLD OF LIFE 



A MANIFESTATION OF 

CREATIVE POWER, DIRECTIVE MIND 

AND ULTIMATE PURPOSE 



BY 

ALFRED RUSSEL WALLACE 

O.M., F.R.S., D.C.L., Etc. 



NEW YORK 
MOFFAT, YARD & COMPANY 

I 9 I I 



Copyright, 1910, 191 1, by 

Moffat, Yard and Company 

New York 



All Rights Reserved 
Published January, 191 1 



PEEFACE 

In the present volume I have attempted to summarise and 
complete my half-century of thought and work on the Dar- 
winian theory of evolution. In several directions, I have 
extended the scope and application of the theory, and have 
shown that it is capable of explaining many of the phenomena 
of living things hitherto thought to be beyond its range. 

Among these are the detailed distribution of plants and 
animals, which I have discussed at some length. It occupies 
about one-fourth of the volume (Chapters II. to VI.)? and 
brings out certain facts and conclusions which I believe mil 
be of interest to all plant-lovers, and also be not without a 
certain value to botanists. 

'Next in importance are three chapters (X., XL, and XII.) 
devoted to a general review of the Geological Eecord and a 
discussion of the various problems arising out of it. Some 
of the conclusions to which this examination leads us are, I 
believe, both important and of much general interest. 

In Chapter VIII. I have endeavoured to show natural selec- 
tion actually at work in the continually perfecting that won- 
derful co-adaptation of the most diverse forms of life which 
pervades all nature. Some little-known aspects of bird-migra- 
tion are here discussed, and proof is given of the enormous 
importance of mosquitoes for the very existence of considerable 
proportion of our birds, including most of our most favoured 
pets and songsters. This chapter will, I think, have a special 
interest for every bird-lover. 

106920 



yi THE WOKLD OF LIFE 

In Chapter IX. I deal with some little-known phenomena 
in that hitherto neglected field of enquiry which I have termed 
" Eecognition Marks." Besides the obvious uses implied by 
their name, I have shown that they are of great importance — 
perhaps absolutely essential — in the process of the evolution 
of new species. During the enquiry I have arrived at the 
somewhat startling conclusion that the exquisite variety and 
beauty of insect-coloration and marking have not been devel- 
oped through their ovni visual perceptions, but mainly — per- 
haps even exclusively — through those of higher animals. I 
show that brilliant butterflies do not, and almost certainly 
cannot, recognise each other by colour, and that they probably 
do not even perceive colour at all except as to a certain extent 
presenting visual differences. 

But besides the discussion of these and several other allied 
subjects, the most prominent feature of my book is that I enter 
into popular yet critical examination of those underlying funda- 
mental problems which Darwin purposely excluded from his 
"works as being beyond the scope of his enquiry. Such are the 
nature and causes of Life itself, and more especially of its 
most fundamental and mysterious powers — growi:h and repro- 
duction. 

I first endeavour to show (in Chapter XIV.) by a careful 
consideration of the structure of the bird's feather ; of the 
marvellous transformations of the higher insects ; and, more 
especially of the highly elaborated wing-scales of the Lepidop- 
tera (as easily accessible examples of what is going on in every 
part of the structure of every living thing), the absolute neces- 
sity for an organising and directive Life-Principle in order to 
account for the very possibility of these complex out-growths. 



PEEFACE 



Vll 



I argue that they necessarily imply first, a Creative Power, 
which so constituted matter as to render these marvels pos- 
sible; next, a directive Mind, which is demanded at every step 
of the process we term growth and often look upon as so 
simple and natural a process as to require no explanation; 
and, lastly, an ultimate Purpose, in the very existence of the 
whole vast life-world in all its long course of evolution through- 
out the eons of geological time. This Purpose, which alone 
throws light on many of the mysteries of its mode of evolu- 
tion, I hold to be the development of Man, the one crowning 
product of the whole cosmic process of life-development; the 
only being which can to some extent comprehend nature ; which 
can perceive and trace out her modes of action ; which can 
appreciate the hidden forces and motions everywhere at w^ork, 
and can deduce from them all a supreme and overruling mind 
as their necessary cause. 

If we accept some such view as I have now indicated, I 
show (in Chapters XV. and XVI.) how strongly it is sup- 
ported and enforced by a long series of facts and co-relations 
which we can hardly look upon as all purely accidental coin- 
cidences. Such are the infinitely varied products of living 
things which serve man's purposes and man's alone — not only 
by supplying his material wants, and by gratifying his higher 
tastes and emotions, but as rendering possible many of those 
advances in the arts and in science which we claim to be the 
highest proofs of his superiority to the brutes and of his 
advancing civilisation. 

From a consideration of these better-knoAvn facts I proceed 
(in Chapter XXII.) to an exposition of the mystery of cell- 
growth; to a consideration of the elements in their special 
relation to the earth itself and to the life-world ; while in the 



viii THE WORLD OE LIFE 

last chapter I endeavour to show the purpose of that law of 
diversity which seems to pervade the whole material Universe. 
As an '' excursus," I devote Chapter XIX. to a discussion of 
the nature, extent, and uses of Pain, as strictly deduced from 
the law of Evolution. Strangely enough, this has never, I 
believe, been done before ; and it enables us to answer the 
question — ^' Is Xature Cruel ? " with a decided negative. 

This outline of the varied contents and objects of my book, 
wdll, I hope, be useful to my readers, and especially to my 
reviewers, by directing their attention to those parts of the 
work in which they may be more especially interested. 

I also wish to point out that, however strange and heretical 
some of my beliefs and suggestions may appear to be, I claim 
that they have only been arrived at by a careful study of the 
facts and conditions of the problem. I mention this because 
numerous critics of my former work — Man's Place in the 
Universe (to which this may be considered supplementary) — ■ 
treated the conclusions there arrived at as if they were wholly 
matters of opinion or imagination, and founded (as were their 
own) on personal likes or dislikes, without any appeal to evi- 
dence or to reasoning. 

I have now only to express my thanks to the friends and 
strangers who have kindly assisted me with numerical and 
other data for various portions of my work ; as well as to those 
publishers and authors who have allowed me to use the en- 
gravings or photographs with which my book is illustrated. 
They are in, every case (I believe) acknowledged in the text, 
or on the various plates and figures. 



Broadstone, Wimborne, 
November 1910. 



CONTENTS 

CHAPTER I 

PAGE 

What is Life and Whence it Comes 1 

CHAPTER II 
Species — their Numbers, Variety, and Distribution ... 12 

CHAPTER III 

The Numerical Distribution of British Plants : Temperate 
Floras Compared 24 

CHAPTER IV 
The Tropical Floras of the World • . . 43 

CHAPTER V 
The Distribution of Animals 89 

CHAPTER VI 

The Numerical Distribution of Species in Relation to Evolu- 
tion 100 

CHAPTER VII 
Heredity, Variation, Increase 109 

CHAPTER VIII 

Illustrative Cases of Natural Selection and Adaptation . . 134 

ix 



X THE WORLD OF LIPE 

CHAPTEE IX ' 



PAGE 



The Importance of Eecognition-marks in Evolution . . .168 

CHAPTEE X 

The Earth's Surface-changes the Motive Power of Evolution 187 

CHAPTEE XI 

The Progressive Development of the Life-World as shown 
by the Geological Eecord 303 

CHAPTEE XII 
Life of the Tertiary Period 235 

CHAPTEE XIII 
Some Extensions of Darwin's Theory ....... 371 

CHAPTEE XIY 

Birds and Insects as Proofs of an Organising and Directive 
Life-principle 309 

CHAPTEE XV 

General Adaptation of Plants, Animals, and Man . . . .321) 

CHAPTEE XVI 

The Vegetable Kingdom in its special Eelation to Man . . 350 

CHAPTEE XVII 
The Mystery of the Cell 361 



CONTENTS xi 

CHAPTER XVIII 

PAGE 

The Elements and Water in Eelation to the Life-AYorld . . 383 

CHAPTER XIX 
Is Nature Cruel? The Uses of Pain 398 

CHAPTER XX 
Infinite Variety the Law of the Universe 415 



LIST OF ILLUSTRATIONS 

FIG. PAGE 

1. Forest in Kelantan, Malay Poninsula 48 

2. Forest in Perak, Malay Peninsula 50 

3. Campos of Lagoa Santa, Brazil GO 

4. View of Campo Cerrado, Lagoa Santa 70 

5. View at Lapa Vermelha Eocks, Lagoa Santa . . . 72 

6. Casselia chamaedrifoUa 73 

7. Andira laurifolia 74 

8. A Forest Stream, West Java 80 

9. Diagram of Curve of Stature IIG 

10. Diagram of Variation 118 

11. American Bison 124 

12. The Lemming 129 

13. Shooting Wild Cleese at the Arctic Circle .... 147 

14. Geese Migrating 148 

15. Mr. Seebohm's Mosquito Veil 149 

16. Watching Grey Plover Among Mosquitoes .... 150 

17. Ice Breaking up, Petchora Eiver 152 

18. Midsummer on the Tundra 153 

19. Sudden Arrival of Birds 154 

20. Grey Plover, Xest and Young 156 

21. The Higher Tundra 159 

22. Migration Xight at Heligoland 162 

23. Mimicry of Wasp by a Beetle 170 

24. Tragelaphus speJcei 1<4 

25. Boocercus euryceros 1<4 

26. Gazella granii 1^4 

27. Gazelli walleri l'^4 

28. Strepsiceros Jciidu 1^" 

29. Strepsiceros imherhis 1^6 

30. Bubalis JacTcsonia 1'^^ 

31. ^pyceros melampus 1*^6 

• • • 

Xlll 



xiv THE WORLD OF LIFE 



riG. 



PAGE 



32. Cohus leche 178 

33. Cohus defossa 178 

34. Cohus Maria 178 

35. Oryx Gazella 178 

36. (E dicnertius grallarius 176 

37. (Edicnemus magnirostris 176 

38. Great Indian Stone Curlew 177 

39. Thelodus scoticus 208 

40. Pteraspis rostrata 208 

41. Cephalaspis murchisoiii 209 

42. Protocercal Tail 209 

43. Heterocercal Tail 209 

44. Homocercal Tail 210 

45. Pariasaurus Bainii 214 

46. Skull of Dicynodon lacerticeps 214 

47. Slvull of JEIusaurus felinus 215 

48. Skull of Inostransevia 216 

49. Eestoration of Dimetrodon 216 

50. Skeleton of Iguanodon 218 

51. Eestoration of Iguanodon 218 

52. Skull of Iguanodon 218 

53. Skeleton of Armoured Dinosaur 218 

54. Skull of Horned Dinosaur 219 

55. Eestoration of Stegosaurus 220 

56. Sauropodous Dinosaur 221 

57. Skeleton of Diplodocus carnegii 222 

58. Skull of Sauropodous Dinosaur 222 

59. Skull of a Theropodous Dinosaur 222 

60. Outline and Skeleton of Plesiosaurus macro cephalus . 224 

61. Outline and Skeleton of Ichthyosaurus communis . . 224 

62. Bones and Paddles of Ichthyosaurus 224 

63. Skeleton of Pterodactylus spectahilis 225 

64. Eestoration of Rhymphorhynchus phyllurus .... 226 

65. Toothless Pterodactyl 226 

66. Skull of Peteranodon longiceps 227 

67. Lower Jaw of Phasolothcrium huchlandi 228 

68. Jaw and Teeth of Spalacotherium. tricuspidens . • • 228 



LIST OF ILLUSTRxVTIONS xv 

FIG. . PAGE 

69. Jaw of Triconodon mordax 228 

70. Drawing of the Fossil Lizard-tailed Bird .... 230 

71. Skull of Arcliccoptcryxsiemensi 231 

72. Skeleton of Phenacodus primwvus 232 

73. Skeleton of Uintatherium ingens 236 

74. Skull of Uintatherium cornutum 237 

75. Skeleton of Titanotherium rohustum 238 

76. Skull of Arsinoitheriiim zitteli 240 

77. Skeleton of a Creodont 242 

78. Skeleton of Hyopotamus brachyrhynchus 243 

79. Anoplotherium commune 244 

80. Palwotheriiim magnum 244 

81. Skull of Moeriilierium hjonsi 244 

82. Skulls of Ancestral Elephants 246 

83. Skeleton of Tetrahelodon angvstidens 246 

84. Probable Appearance of Tetrahelodon augustidens . . 246 

85. Skeleton of Mastodon americanus 247 

^Q. Skeleton of Mammoth Elephas promigenius .... 249 

87. Skeleton of Toxodon platensis 250 

S8. Skeleton of Glyptodon clavipeR 253 

89. Probable Appearance of tlio Giant Ground-sloth . . 254 

90. Mylodon rohustus 254 

91. Skeleton of Scelidotlierium leptocephalum .... 255 

92. Skull of an Extinct Marsupial 257 

93. Skull of Thylacoleo carnifex 258 

94. Sabre-toothed Tiger 284 

95. Skeleton of Giant Deer 284 

96. Conocoryphe sultzeri .» 287 

97. Paradonides hohemiciis . ♦ 287 

98. Acidaspis dufrenoyi 288 

99. Ceratites nodosus 289 

100. Trachyceras aon 28 J 

101. Crioceras emerici 289 

102. Heieroceras emerici 289 

103. Macroscaphites ivanii . . o 290 

104. Hamites rotundus -^"^^ 

105. Ptychoceras emericiciniim '^•^^ 



xvi THE WORLD OF LIFE 

PAGE 

106. Ancyloceroe matheronianiinis 390 

107. Head of Babirusa 296 

108. Perspective View of a Part of a Wing-feather . . .313 

109. Oblique Section Showing how the Barbules hook To- 

gether 312 

110. Diagram of Nuclear Division 3 TO 



THE WORLD OF LIFE 



CHAPTER I 

WHAT LIFE IS, AjI^D WHENCE IT COMES 

When primeval man first rose above the brutes from which 
he was developed ; when, by means of his superior intellect, 
he had acquired speech and the use of fire ; and more espe- 
cially when his reasoning and reflecting faculties caused him 
to ask those questions which every child now asks about the 
world around it — what is this ? and why is that ? — he would, 
for the first time, perceive and wonder at the great contrast 
between the living and the not-living things around him. 

He would first observe that the animals which he caught 
and killed for food, though so unlike himself outwardly, were 
yet very like his fellow-men in their internal structure. He 
would see that their bony framework was almost identical in 
shape and in substance with his own; that they possessed flesh 
and blood, that they had eyes, nose, and ears; that presumably 
they had senses like his own, sensations like his own ; that they 
lived by food and drink as he did, and yet were in many ways 
so different. Above all, he would soon notice how inferior 
they were to himself in intellect, inasmuch as they never made 
fires, never used any kind of tools or weapons ; and that, 
although many of them were much stronger than he was, yet 
his superiority in these things, and in making traps or pitfalls 
to capture them, showed that he was really their superior and 
their master. 

Gradually, probably very slowly, he would extend these 
observations to all the lower forms of life, even wdjen both 

1 



2 THE WORLD OF LIFE 

externally and internally he could find no resemblance what- 
ever to his own body; to crabs and winged insects, to land- 
shells and sea-shells, and ultimately to everything which by 
moving and feeding, by growdng and dying, showed that it 
was, like himself, alive. Here, probably, he would rest for 
awhile, and it might require several generations of incipient 
philosophers to extend the great generalisation of " life " to 
that omnipresent clothing of the earth's surface produced by 
the infinitely varied forms of vegetation. The more familiar 
any phenomenon is — the more it is absolutely essential to 
our life and well-being — the less attention we pay to it and 
the less it seems to need any special explanation. Trees, shrubs, 
and herbs, being outgrowths from the soil, being incapable of 
any bodily motion and usually exhibiting no indications of 
sensation, might w^ell have been looked upon as a necessary 
appendage of the earth, analogous to the hair of mammals or 
the feathers of birds. It was probably long before their end- 
less diversity attracted much notice, except in so far as the 
fruits or the roots were eatable, or the stems or foliage or bark 
useful for huts or clothing ; wdiile the idea that there is in them 
any essential feature connecting them wdth animals and en- 
titling them to be classed all together as members of the great 
^vorld of life would only arise at a considerably later stage 
of development. 

It is, in fact, only in recent times that the very close resem- 
blance of plants and animals has been generally recognised. 
The basis of the structure of both is the almost indistinguish- 
able cell ; both grow from germs ; both have a varied life-period 
from a few" months to a maximum of a few" hundreds of vears : 
both in all their more highly organised forms, and in many of 
their lower types also, are bisexual ; both consist of an immense 
variety of distinct species, which can be classified in the same 
way into higher and higher groups; the laws of variation, 
heredity, and the struggle for existence apply equally to both, 
and their evolution under these laws has gone on in a parallel 
course from the earliest periods of the geological record. 



WHAT LIFE IS 3 

The differences between plants and animals are, however, 
equally prominent and fundamental. The former are, with 
few exceptions, permanently attached to the soil ; they absorb 
nourishment in the liquid or gaseous state only, and their tissues 
are almost wholly built up from inorganic matter, while they 
give no clear indications of the possession of sensation or vol- 
untary motion. But notwithstanding these marked differences, 
both animals and plants are at once distinguished from all the 
other forms of matter that constitute the earth on which they 
live, by the crowning fact that they are alive; that they grow 
from minute germs into highly organised structures; that the 
functions of their several organs are definite and highly varied, 
and such as no dead matter does or can perform ; that they are 
in a state of constant internal flux, assimilating new material 
and throwing off that which has been used or is hurtful, so as 
to preserve an identity of form and structure amid constant 
change. This continuous rebuilding of an ever-changing highly 
complex structure, so as to preserve identity of type and at 
the same time a continuous individuality of each of many 
myriads of examples of that type, is a characteristic found 
nowhere in the inorganic world. 

So marvellous and so varied are the phenomena presented 
by living things, so completely do their powers transcend those 
of all other forms of matter subjected to mechanical, physical, 
or chemical laws, that biologists have vainly endeavoured to 
find out what is at the bottom of their strange manifestations, 
and to give precise definitions, in terms of physical science, of 
what "life'' really is. One authority (in Chambers's Ency- 
clopaedia) summed it up in three w^ords — "Continuity, 
Ehythm, and Freedom," — true, perhaps, but not explanatory ; 
while Herbert Spencer declared it to be — " the definite com- 
bination of heterogeneous changes, both simultaneous and suc- 
cessive, in correspondence with external co-existences and 
sequences." This is so technical and abstract as to be unin- 
telligible to ordinary readers. 

The following attempt at a tolerably complete definition 



4 THE WORLD OF LIFE 

appears to sum up the main distinctive characters of living 
things : — 

Life is that 'power which, primarily from air and water and 
the substances dissolved therein, builds up organised and highly 
complex structures possessing definite forms and functions: 
these are preserved m a continuous state of decay and repair by 
internal circulation of fluids and gases; they reproduce their 
like, go through various phases of youth, maturity, and age, 
die, and quickly decompose into their constituent elements. 
They thus form continuous series of similar individuals; and, 
so long as external conditions render their existence possible, 
seem to possess a potential immortality. 

The characteristics here enumerated are those which apply 
to both plants and animals, and to no other forms of matter 
whatever. It is often stated that crystals exhibit the essential 
features of some of the lowest plants ; but it is evident that, 
with the exception of the one item of " definite form/^ they 
in no way resemble living organisms. There is no doubt, how- 
ever, that crystals do exhibit definite forms, built up by the 
atoms or molecules of various elements or compounds under 
special conditions. But this takes us a very small way towards 
the complex structure and organisation of living things. 

There are still people who vaguely believe that ^^ stones 
grow," or that '^ all matter is really alive," or that, in their 
lowest and simplest forms, the organic and the inorganic are 
indistinguishable. For these ideas, however, there is not a 
particle of scientific justification. But the belief that '^ life " 
is a product of matter acted upon by chemical, electrical, or 
other physical forces, is very widely accepted by men of science 
at the present day, perhaps by a majority. It is, in fact, held 
to be the only scientific view, under the name of ^' monism " ; 
while the belief that ^^ life " is sui generis, that it is due to 
other laws than those which act upon dead or unorganised 
matter, that it affords evidence of an indwelling power and 
guidance of a special nature, is held to be unscientific — to 
be, in fact, an indication of something akin to, if not actually 



WHAT LIFE IS 5 

constituting, an old-fashioned superstition. That such a view 
is not uncommon may be shown by a few extracts from scien- 
tific writers of some eminence. 

The well-known German biologist Ernst Haeckel, in a recent 
work, makes the following statement : 

" The peculiar phenomenon of consciousness is not, as Du Bois- 
Eeymond and the dualistic school would have us believe, a com- 
pletely transcendental problem ; it is, as I showed thirty-three years 
ago, a physiological problem, and, as such, must be reduced to the 
phenomena of physics and chemistry " (The Eiddle of the Uni- 
verse, p. 65, translated by Joseph M'Cabe). 

Again he says : 

" The two fundamental forms of substance, ponderable matter 
and ether, are not dead, and only moved by extrinsic force, but they 
are endowed with sensation and will (although, naturally, of the 
lowest grade) ; they experience an inclination for condensation, a 
dislike of strain; they strive after the one and struggle against the 
other'' (p. 78). 

In these two passages we have a self-contradiction in mean- 
ing if not in actual words. In the first, he reduces conscious- 
ness to phenomena of physics and chemistry ; in the second 
he declares that both matter and ether possess sensation and 
will. But in another passage he says he conceives ^^ the ele- 
mentary psychic qualities of sensation and will which may be 
attributed to atoms to be unconscious" (p. 64). 

It is this quite unintelligible theory of matter and ether 
possessing sensation and will, being able to strive and struggle 
and yet be unconscious, which enables him to say: 

"We hold with Goethe that matter cannot exist and be oper- 
ative without spirit, nor spirit without matter. We adhere firmly 
to the pure, unequivocal monism of Spinoza : Matter, or infinitely 
extended substance, and Spirit (or Energy), or sensitive and think- 
ing substance, are the two fundamental attributes, or principal 
properties, of the all-embracing essence of the world, the universal 
substance" (p. 8). 



6 THE WOELD OF LIFE 

Here we have yet another contradiction — that the tJiinking 
infinite substance is unconscious! This leads to his theory 
of the " cell-soul/' which is the origin of all consciousness, hut 
which is itself unconscious. This he reiterates emphatically. 
He tells us that at a certain grade of organisation '^ conscious- 
ness has been gradually evolved from the psychic reflex activity, 
and now conscious voluntary action appears" (p. 41). Along 
wdth these strange conceptions, "vvhich really explain nothing, 
he propounds his " Law of Substance " as the one great foun- 
dation of the universe. This is merely another name for 
" persistence of force " or ^' conservation of energ}^," yet at 
the end of the chapter expounding it he claims that, '' in a 
negative way, it rules out the three central dogmas of meta- 
physics — God, freedom, and immortality" (p. 83). A little 
further on he again states his position thus: 

" The development of the universe is a monistic mechanical 
process, in which we discover no aim or purpose whatever; what 
we call design in the organic world is a special result of biological 
agencies; neither in the evolution of the heavenly bodies, nor in 
that of the crust of the earth do we find any trace of a controlling 
purpose — all is the result of chance.^' 

Then, after discussing what is meant by chance, he con- 
cludes : 

" That, however, does not prevent us from recognising in each 
' chance ' event, as we do in the evolution of the entire cosmos, the 
universal sovereignty of nature's supreme law, the taw of sub' 
stance'* (p. 97). 

Again, he defines his position still more frankly: 

*' Atheism affirms that there are no gods or goddesses, assuming 
that god means a personal, extra-mundane entity. This ^ godless 
world-system ' substantially agrees with the monism or pantheism 
of the modern scientist. It is only another expression for it, em- 
phasising its negative aspect, the non-existence of any supernatural 
deity" (p. 103). 



WHAT LIFE IS 7 

These vague and often incomprehensible assertions are inter- 
spersed with others equally unprovable, and often worded so 
as to be very offensive to religious minds. After having put 
forth a host of assertions as to a possible future state, which 
exhibit a deplorable ignorance of the views of many advanced 
thinkers in all the Churches, he says: 

" Our own ^ human nature ' which exalted itself into an image 
of God in an anthropistic illusion, sinks to the level of a placental 
mammal, which has no more value for the universe at large than 
the ant, the fly of a summer's day, the microscopic infusorium, or 
the smallest bacillus. Humanity is but a transitory phase of the 
evolution of an eternal substance, a particular phenomenal form of 
matter and energy, the true proportion of which we soon perceive 
when we set it on the background of infinite space and eternal 
time" (p. 87). 

The writings of Haeckel, the extremely dogmatic and asser- 
tive character of which have been illustrated in the preceding 
quotations, have had an immense influence on many classes of 
readers, who, when a man becomes widely known as a great 
authority in any department of science, accept him as a safe 
guide in any other departments on which he expresses his 
opinions. But the fact is that he has gone altogether out of 
his own department of biological knowledge, and even beyond 
the whole range of physical science, when he attempts to deal 
with problems involving '' infinity " and ^' eternity." He de- 
clares that " matter," or the material universe, is infinite, as 
is the '' ether," and that together they fill infinite S2:)ace, and 
that both are ^^ eternal " and both '' alive." ^one of these 
things can possibly be hnown, yet he states them as positive 
facts. The whole teaching of astronomy by the greatest 
astronomers to-day is that the evidence now at our command 
points to the conclusion that our material universe is finite, 
and that we are rapidly approaching to a knowledge of its 
extent. Our yearly increasing acquaintance with the possibil- 
ities of nature leads us to the conclusion that in infinite space 



8 THE WORLD OF LIFE 

there lyiay be other universes besides ours; but if so, they may 
l^ossibly be different from ours — not of matter and ether only. 
To assert the contrary, as Ilaeckel does so confidently, is surely 
not science, and very bad philosophy. 

He further implies, and even expressly states, that there is 
no spirit-world at all ; that if life exists in other worlds it must 
be material, physical life; and that, as all worlds move in 
cycles of development, maturity, and destruction, all life must 
go through the same phases — that this has gone on from all 
eternity past, and will go on for all eternity to come, with no 
past and no future possible, but the continual rise of life up to 
a certain limited grade, which life is always doomed to extinct 
tion. And it is claimed that this eternal succession of futile 
cycles of chance development and certain extinction is, as an 
interpretation of nature, to be preferred to any others ; and 
especially to those which recognise mind as superior to matter, 
which see in the development of the human intellect the prom- 
ise of a future life, and which have in our own day found a 
large mass of evidence justifying that belief. 

With Professor HaeckeFs dislike of the dogmas of theo- 
logians, and their claims to absolute knowledge of the nature 
and attributes of the inscrutable mind that is the power within 
and behind and around nature, many of us have the greatest 
sympathy ; but we have none with his unfounded dogmatism 
of combined negation and omniscience, and more especially 
when this assumption of superior knowledge seems to be put 
forward to conceal his real ignorance of the nature of life 
itself. He evades altogether any attempt to solve the various 
difficult problems of nutrition, assimilation, and growth, some 
of which, in the case of birds and insects, I shall endeavour 
to set forth as clearly as possible in the present volume. As 
Professor Weismann well puts it, the causes and mechanism 
by which it comes about that the infinitely varied materials 
of which organisms are built up ^' are always in the right 
place, and develop into cells at the right time," are never 
touched upon in the various theories of heredity that have been 



WHAT LIFE IS 9 

put forward, and least of all in that of Haeckel, who comes 
before us with what he claims to be a solution of the Riddle 
of the Universe. 

Huxley on the Nature and Origin of Life 

Although our greatest philosophical biologist, the late Pro- 
fessor T. H. Huxley, opposed the theory of a '' vital force " 
as strongly as Haeckel himself, I am inclined to think that 
he did so because it is a mere verbal explanation instead of 
being a fundamental one. It conceals our real ignorance un- 
der a special term. In his Introduction to the Classification 
of Animals (1869), in his account of the Rhizopoda (the 
group including the Amoebse and Foraminifera), he says: 

"Nor is there any group in the animal kingdom which more 
admirably illustrates a very well-founded doctrine, and one which 
was often advocated by John Hunter, that life is the cause and not 
the consequence of organisation; for in these lowest forms of ani- 
mal life there is absolutely nothing worthy of the name of organi- 
sation to be discovered by the microscopist, though assisted by the 
beautiful instruments that are now constructed. . . . It is 
structureless and organless, and without definitely formed parts. 
Yet it possesses all the essential properties and characters of vitality. 
Nay, more, it can produce a shell; a structure, in many cases, of 
extraordinary complexity and most singular beauty. 

" That this particle of jelly is capable of guiding physical forces 
in such a manner as to give rise to those exquisite and almost 
mathematically-arranged structures — being itself structureless 
and without permanent distinction or separation of parts — is 
to my mind a fact of the profoundest significance'^ (p. 10). 

This was written only a year after the celebrated lecture 
on " The Physical Basis of Life," in which Huxley made 
statements which seem opposed to those above quoted, and which 
certainly appear to be less philosophical. For example, he 
says that when carbon, hydrogen, oxygen, and nitrogen are 
combined with some other elements, they produce carbonic acid, 
water, and nitrogenous salts. These compounds are all life- 



10 THE WORLD OF LIFE 

less. " But wlien they are brought together under certain 
conditions they give rise to the still more complex body, proto- 
plasm, and this protoplasm exhibits the phenomena of life " 
(p. 52). Then follows an exposition of the well-known argu- 
ment as to water and crystals being produced by the " proper- 
ties " of their constituent elements, with this conclusion : 

" Is the case any way changed when carbonic acid, water, and 
nitrogenous salts disappear, and in their place, under the influence 
of pre-existing living protoplasm, an equivalent weight of the 
matter of life makes its appearance?" (p. 53). 

But here we have the words I have italicised introduced 
which were not in the previous staj:ement; and these are of 
fundamental importance considering the tremendous conclu- 
sion he goes on to draw from them — " that the thoughts to 
which I am now giving utterance are the exj)ression of molec- 
ular changes in that matter of life which is the source of our 
other vital phenomena." At the end of the lecture he says 
that " it is of little moment whether we express the phenomena 
of matter in terms of spirit, or the phenomena of spirit in 
terms of matter — each statement has a certain relative truth." 
But he thinks that in matters of science the materialistic ter- 
minology is in every way to be preferred. 

This is vague and unsatisfactory. It is not a mere question 
of terminology ; but his statement that " thought is the expres- 
sion of molecular change in protoplasm " is a mere begging 
of the whole question, both because it is absolutely unproved, 
and is also inconsistent with that later and clearer statement 
that " life is the cause of organisation " ; but, if so, life must 
be antecedent to organisation, and can only be conceived as 
indissolubly connected with spirit and with thought, and with 
the cause of the directive energy everyw^here manifested in the 
growth of living things. 

In the present volume I am endeavouring to arrive at a 
juster conception of the mystery of the Life- World than that 
of Professor Haeckel, and bv a verv different method. I shall 



WHAT LIFE IS 11 

endeavour to give a kind of bird's-eye sketch of the great life- 
drama in many of its broader and less-known phases, showing 
how they all form parts of the grand system of evolution, 
through adaptation to continuous changes in the outer world. 
I shall also endeavour to penetrate into some of the less trodden 
paths of nature-study, in order to exhibit the many indications 
that exist of the preparation of the Earth for Man from the 
remotest eons of geological time. 



CHAPTER II 

SPECIES THEIK NUMBEKS, VAKIETY, AND DISTRIBUTION 

When we begin to inquire into the main features, the mode 
of development, the past history, and the probable origin of 
the great World of Life of which we form a part, which 
encloses us in its countless ramifications, and upon whose pres- 
ence in ample quantity we depend for our daily food and 
continued existence, we have perpetually to discuss and to deal 
with those entities technically kno^vn as species, but which are 
ordinarily referred to as soi'ts or kinds of plants and animals. 
When we ask how many hinds of deer or of thiTishes, of trout 
or of butterflies, inhabit Britain, w^e mean exactly the same 
thing as the biologist means by species, though we may not be 
able to define what we mean so precisely as he does. 

Many people imagine, however, that Darwin's theory proves 
that there are no such things as species ; but this is a complete 
misconception, though some biologists use language which 
seems to support it. To myself, and I believe to most natural- 
ists, species are quite as real and quite as important as when 
they were held to be special creations. They are even more 
important, because they constitute the only definite, easily rec- 
ogTiised, and easily defined entities which form the starting- 
point in all rational study of the vast complex of living things. 
They are now known to be not fixed and immutable as for- 
merly supposed; yet the great mass of them are stable within 
very narrow limits, w^hile their changes of form are so slow, 
that it is only now, after fifty years of continuous search by 
countless acute observers, that we have been able to discover 
a very few cases in which a real change — the actual produc- 
tion of new species — appears to be going on before our eyes. 
The reader may therefore rest assured that there is no mystery 

1^ 



DISTRIBUTIO'N^ OF SPECIES 13 

in the word species, but that he may take it as meaning the 
same as kind, in regard to animals and plants in a state of 
nature, and that he will have no difficulty in following the 
various discussions and expositions in which this term is nec- 
essarily so prominent. The reason why species is the better 
term is because hind is used in two distinct senses — that of 
species when we speak of kinds of deer, of squirrels, or of 
thrushes, but also that of a genus or a family when we 
speak of the deer, squirrel, or thrush kind, as meaning the 
whole group of these animals. If we used the word tribe 
instead of hind in this latter sense, all ambiguity would be 
avoided. 

Eew persons who have not studied some branch of natural 
history have any idea of the vast extent, the infinite variety, 
the omnipresence and the intermingling of the varied species 
of animals and plants, and still less of their wonderful co-adap- 
tation and interdependence. It is these very characteristics 
that are least dwelt upon in books on natural history, and they 
are largely overlooked even in works on evolution. Yet they 
form the very basis of the phenomena to be explained, and 
furnish examples of development through survival of the fittest, 
on a larger scale and often of easier comprehension than the 
special cases most frequently adduced. It is this ground-work 
of the whole subject that we will now proceed to consider. 

The Distribution of Local and ^yorld Species 

The first important group of facts which we have to con- 
sider is that which relates to the number of existing species 
of the tw^o great divisions of life, plants and animals, and their 
mode of distribution over the earth's surface. 

Every one who begins to study and collect any gToup of 
animals or plants is at once struck by the fact that certain 
fields, or woods, or hills are inhabited by species which he can 
find nowhere else ; and further, that, whereas some kinds are 
very common and are to be found almost everywliere, others 
are scarce and only occur in small numbers even in the places 



14 THE WORLD OF LIFE 

where alone they are usually to be found. These peculiarities 
are most strongly marked in the case of plants, and in a less 
degree among insects and land-shells; and in the former group 
they are easily seen to depend mainly on such obvious peculiari- 
ties as soil and moisture, exposure to sun or wind, the pres- 
ence or absence of woods, streams, or mountains. 

But besides these inorganic causes — soil, climate, aspect, 
etc. — which seem primarily to determine the distribution of 
plants, and, through them, of many animals, there are other 
and often more powerful causes in the organic environment 
which acts in a variety of ways. Thus, it has been noticed 
that over fields or heaths where cattle and horses have free 
access seedling trees and shrubs are so constantly eaten down 
that none ever grow to maturity, even although there may be 
plenty of trees and woods around. But if a portion of this 
very same land is enclosed and all herbivorous quadrupeds 
excluded, it very quickly becomes covered with a dense vege- 
tation of trees and shrubs. Again, it has been noticed that 
on turfy banks constantly cropped by sheep a very large variety 
of dwarf plants are to be found. But if these animals are 
kept out and the vegetation allowed to grow* freely, many of 
the dwarfer and more delicate plants disappear owing to the 
rapid growth of grasses, sedges, or shrubby plants, which, by 
keeping off the sun and air and exhausting the soil, prevent 
the former kinds from producing seed, so that in a few years 
they die out and the vegetation becomes more uniform. 

A modified form of the same general law is seen when any 
ground is cleared of all vegetation, perhaps cultivated for a 
year or two, and then left fallow. A large crop of weeds 
then grows up (the seeds of which, must have beeoi brought 
by the wind or by birds, or have lain dormant in the ground) ; 
but in the second and third years these change their propor- 
tions, some disappear, while a few new ones arrive, and this 
change goes on till a stable form of vegetation is formed, often 
very different from that of the surrounding country. Such 
changes as these have been observed by local botanists on rail- 



DISTRIBUTION OF SPECIES 15 

way banks, of which I have given several examples in my 
Island Life (p. 513, footnote). All these phenomena, and 
many others which will be referred to later, are manifestly 
due to that " struggle for existence " which is one of the great 
factors of evolution through " survival of the fittest." 

A Lincolnshire clergyman (Rev. E. Adrian Woodruff e-Pea- 
cock of Cadney) has long studied the distribution of plants in 
a very minute and interesting manner, more especially in his 
own parish, but very extensively over the whole county. His 
more exact method is to divide up a field into squares of about 
16 feet each way with pegs, and then to note on special forms 
or note-books (1) a list of the species found in each square, 
and (2) the frequency (or proportion) of the occurrence of 
each species. From these the frequency over the whole field 
can be estimated, and the botanical peculiarities of various 
fields very accurately determined. By comparing the detailed 
flora of each field with its surface-geology, aspect, altitude, 
degree of moisture or aridity, etc., a very accurate conclusion 
as to the likes and dislikes of particular plants may be arrived 
at. 

As an example of the detailed treatment of a rather uncom- 
mon yet widely distributed plant, he has sent me a copy of his 
paper on the Black Horehound (Ballota nigra), sl species not 
uncommon over much of Central Europe, but scattered over 
Central and Southern Britain only in a few favourable locali- 
ties. In Lincolnshire it is found all over the county in suitable 
spots, but prefers a warm, open, and limy soil, as shown by 
150 records giving notes of its occurrence. The general results 
of the inquiry are thus given: 

"AVhen the sheets of notes are analysed the following points 
come out. It is a hedge and ditch-side species, but it seems to 
prefer a bank to the flat in the proportion of 10 to 1 ; the sunny 
bank to the shady side of a road running east and west in nearly 
the same proportion. On sandy soils it seems to get away from 
the villages to a greater distance than on clays, but perhaps the 
rabbit may explain this. It extends from Cadney village along 



16 THE WORLD OF LIFE 

hedge and ditch banks on roadsides as far as the Sandy Glacial 
Gravel extends in any direction. It is found in bushy ground, 
in old quarries and gravel pits, and on the decaying mud-capping 
of limestone walls. It is exterminated by stock in pasture, unless 
it is protected by the stinging-nettle or by the fouling of the 
ground by rabbits. It is apparently never found in meadows. It 
is even sometimes eaten by cows, when the much-loved Lamium 
album (the white dead-nettle) is left untouched; but it would 
seeem to be taken as a corrective or relish rather than as food. 
It is found so rarely in the open that it would almost appear 
to be a shade species of bushy ground. 

*' To sum up, Ballota nigra can only survive (in Lincolnshire) 
when unconsciously protected by man; for its natural require- 
ments, a bushy, open, limy, lightly stocked soil is practically not 
to be found.^' 

This careful study of a single species of plant gives us an 
excellent picture of the struggle for existence on the outer 
limit of the range of a species, where it first becomes rare, 
and, when the conditions become a little less favourable, ceases 
to exist. How this struggle affects the flora of limited areas 
under slightly different conditions is shown by the same 
writer's comparison of meadow and pasture. 

Tw^o fields of each were chosen in the same parish and with 
the same subsoil (Sandy Glacial Gravel) so as to afford fair 
examples of each. With the one exception of the mode of 
cultivation they were as alike as possible. Both had at some 
remote period been ploughed, as shown by faint ridges, but 
no one living or their immediate predecessors could remember 
them in any different condition from the present one. The 
four fields (29 acres together) contained in all 78 species of 
plants ; but only 46 of these were found in both pasture and 
meadow. The number of species in each was nearly the same 
— 60 in the meadows, 64 in the pastures ; 14 species being 
found only in the meadows and 18 in the pastures. Broadly 
speaking, therefore, one-fifth of all the species growing on these 
29 acres became restricted to well-defined portions of them 



disteibutio:n^ of species 17 

according as these portions were grazed by farm stock or reg- 
ularly mown for hay. 

Again, Mr. Woodruff e-Peacock states, that the assemblage 
of plants that form pasture-lands not only varies with every 
change of soil and climate, but also with any change of the 
animals that feed upon them ; so that any one experienced 
and observant can tell, by the presence of certain plants and 
the absence of others, whether horses, cattle, or sheep have been 
the exclusive or predominant animals that have grazed upon it. 

Another point of some importance is the greater stability 
in the flora of meadow as compared with that of pasture land. 
In the former only one plant was an accidental straggler, while 
in the latter there were 12, or two-thirds of the peculiar spe- 
cies. These are mostly rare, and are very often not truly Brit- 
ish plants, so that they cannot be considered as permanent 
pasture plants. The more stable meadow flora is no doubt 
largely due to the fact that few of the late-flowering plants 
are allowed to produce seed, and though seed may be often 
introduced by birds or the wind, many of these species soon 
die out. It thus appears that though pastures are actually 
richer in species than meadows, yet the latter have a more 
permanent character, as almost all those peculiar to pastures 
are comparatively rare and therefore very liable to disappear 
through very slight changes of conditions. 

These various facts, and many others which cannot be here 
given, serve to show us how very delicate are the mutual rela- 
tions and adjustments of plants to their total environment. 
In proportion as that environment is subject to change of any 
kind, some rare species die out, while others become diminished 
in numbers. And what takes place in single fields or other 
small areas, when closely studied, must certainly occur on a 
much grander scale over the whole earth, and especially in 
those countries and periods when great changes of climate or 
of physical geography are taking place. These detailed studies 
of " Meadow and Pasture Analysis " — as their author terms 
them — thus demonstrate on a very small scale that " struggle 



18 THE WOELD OF LIFE 

for existence " which, as we shall see further on, is always 
present, acts in an almost infinite number of ways, and is one 
of the most important factors in the developmental changes 
of the World of Life. We will now proceed to give some of 
the numerical facts of plant distribution, in various areas small 
and large, as well as over the whole earth; but it will be ad- 
visable first to give a brief account of the way in which this 
is usually dealt with by botanists. 

Four years before the appearance of the Origin of Species 
the great Swiss botanist, Alphonse De Candolle, published one 
of the most remarkable and interesting botanical works in 
existence, his GeogTaphie botanique raisonnee, in two thick vol- 
umes. He not only brought together all the then available 
facts as to plant distribution in every part of the world, studied 
them from almost every point of view, and grouped them in 
relation to every known agency that might be supposed to influ- 
ence their distribution, but at every step he most carefully 
and ingeniously discussed the problems involved, often of a 
very intricate nature, with a view to arriving at a more or less 
complete explanation. 

It is impossible here to give any adequate notion of this 
great work, but a few of the chief subjects treated may be 
mentioned. The effects of temperature and of light upon the 
growth and vitality of plants are first examined, and some 
very interesting conclusions are reached, among others the great 
importance of the time during which any particular degree 
of heat continues. This discussion occupies the first three 
chapters. Sixteen long chapters then deal with " Botanical 
Geography," in which all the geographical conditions that affect 
the distribution of plants are elaborately discussed, such as alti- 
tude, latitude, aspect, humidity, geological and mineralogical 
causes, both in their direct and indirect action, and as apply- 
ing to cultivated as well as ^vild plants. The areas occupied 
by species, both as regards size and shape, are then discussed, 
and the causes that lead to their variations investigated. He 
then shows what are the actual areas in various parts of the 



DISTRIBUTION OF SPECIES 19 

world, and under various geographical conditions, and thus 
arrives at the causes of great extension of certain species from 
Vilest to east in the north temperate zone, or along sea-shores 
or river-banks in the tropics ; while the normal area is consid- 
ered to be '^ massive " rather than elongated. 

Coming then to detailed facts, he shows that about 200 
species (out of the total then known of about 120,000) have 
areas equal to one-third or more of the entire land surface of 
tlie globe. Further, in certain Families (usually called ^Nat- 
ural Orders) there are plants which range from the Arctic 
regions to the southern extremity of the great continents. 
Among the former are our common Marsh Marigold (Caltha 
palustris) and Common Sundew (Drosera rotund i folia), which 
are found in all Northern Europe, Asia, and America ; while 
our common Sowthistle (Sonchus oleraceus) is found scattered 
over the whole globe, tropical as well as temperate, and is per- 
haps the nearest of any known plant to being truly cosmopol- 
itan. 

By a laborious comparison the author arrives at the con- 
clusion that the average area occupied by the species of flower- 
ing plants is rroth part of the whole land surface of the globe. 
But the area varies enormously in different parts of the world. 
Thus, in the wdiole Russian Empire, species have a mean area 
of irVth the land surface, owing to the fact that so many range 
east and west over a large part of Europe and Xorth Asia ; 
while in South Africa the mean range is only W&oth of that 
surface, which expresses the fact of the extreme richness of 
the latter flora, many of the species composing w^hich have 
extremely restricted ranges. He also reaches the eonclusion 
that in passing from the pole to the equator the mean areas 
of the species become smaller. A few examples of very lim- 
ited areas are the following : — Several species of heaths are 
found only on Table Mountain, Cape of Good Hope; Cam- 
immda isopliylJa grows only on one promontory of the coast 
of Genoa; the beautiful Alpine Gromwell (Lithospermum 
Gastoni), on one cliff in the Pyrenees; Wulfenia Carintliiaca, 



20 



THE WORLD OF LIFE 



on one mountain slope in Carintliia ; Primula imperialis, on 
the summit of Mount Pangerago in Java, and many others. 

In order to compare the plants of different parts of the world 
in their various relations, De Candolle divides the whole land 
surface into fifty botanical regions, each distingTiished by the 
possession of a considerable proportion of peculiar species of 
plants. These regions are of greatly varying extent, from Xo. 
18, comprising the whole of Xorthern Asia, to Xo. 10, limited 
to the small island of Tristan d'Acunha in the South Atlantic. 

The list is as follows : — 



A. De Candolle's Botaxical Regions 



1. Arctic zone. 

2. Europe, temperate. 

3. Mediterranean. 

4. Azores, Madeira, Canaries. 

5. Sahara, Cape Verde Islands. 

6. Guinea N., Soudan. 

7. " S., Congo, Benguela. 

8. Island of St. Helena. 
0. South Africa. 

10. Tristan d'Acunha. 

11. Islands of Kerguelen, St. Paul, 

etc. 

12. Madagascar, etc. 

13. Mozambique, Zanzibar. 

14. Abyssinia to Egypt. 

15. Persia, Euphrates. 

16. Caucasus, Armenia. 

17. Tartary east of Caspian. 

18. Siberia, Ural to Kamschatka, 

Lake Aral. 

19. Asia Central. 

20. Afghanistan to Indus. 

21. Nepal to Bhutan. 

22. China, Japan. 

23. Philippines. 

24. Siam, Cochin China. 



25. Burma and Assam. 

26. Bengal, Ganges. 

27. Peninsular India, Ceylon. 

28. Malacca, N. Ireland. 

29. Australia, New Zealand. 

30. Fiji to Marquesas. 

31. Mariannes, Carolines. 

32. Sandwich Islands. 

33. N.W. America. 

34. Canada and United States. 

35. Texas, California, Mexico. 

36. West India Islands. 

37. Venezuela. 

38. Colombia. 

39. Peru. 

40. Galapagos. 

41. Bolivia and Andes. 

42. Guayanas. 

43. Amazonia. 

44. Brazil N.E. 

45. "" W., Paraguay. 

46. " S.E. 

47. Uruguay, La Plata. 

48. Chile, Juan Fernandez. 

49. Patagonia, Falkland Islands. 

50. The Antarctic Archipelago. 



By an extensive comparison of floras all over the world it 
is found that less than Ave per cent, of the total of the kno^vn 
species are found in more than two of these regions. Fam- 



DISTRIBUTION OF SPECIES 21 

ilies which have very few annual species show a still smaller 
percentage (three per cent) ; while those whose species are mostly 
trees or shrubs have less than two per cent which extend to 
more than two regions. 

He also finds that those with fleshy fruits have a wider dis- 
persal than those with dry fruits, and those with very small 
seeds, wider than those with larger seeds. Eighteen species 
only are found to be spread over half the land surface of the 
globe. There are no trees or shrubs among these; grasses are 
most abundant among them ; and composites — the daisy and 
aster family — the least ! This last conclusion seems very 
strange in view of the fact that this family has its seeds so 
frequently provided with special means of dispersal, either by 
the wind or by animals. But he also points out, what is now 
well known to botanists, that the species of Compositse are not 
usually very widely spread ; and also that several other natural 
orders in which the seeds are usually winged for wind-dispersal 
are not more widely distributed than those whose seeds are 
not winged. These facts certainly prove that the dispersal of 
seeds by wind or by birds has been brought about for the pur- 
pose of securing ample means of reproduction Avithin the area 
to which the whole plant has become specially adapted, not 
to facilitate its transmission to distant lands or islands which, 
only in a very few cases, would be suited for its growth and 
full development. Very extensive dispersal must, therefore, 
in most cases be looked upon as an adventitious result of gen- 
eral adaptation to the conditions in which a species exists. 

De Candolle's work also treats very fully the subject of the 
comparative preponderance of the various natural orders of 
plants in different regions or countries. This mode of study- 
ing plant-distribution was introduced by our greatest English 
botanist, Robert Brown, and it is that most generally used by 
modern botanical writers on distribution. It consists in the 
characterisation of the vegetation of each region or district by 
the proportionate abundance in species belonging to the dif- 
ferent natural orders. 



22 THE WOKLD OF LIFE 

This is used in many different ways. In one the minimum 
number of orders whose species added together form one-half 
of the whole flora are given. Thus, it was found that in the 
Province of Bahia (Brazil) the 11 largest natural orders com- 
prise half the whole number of species. In British Guiana 
12 orders are required, and in British India 17. Coming to 
temperate regions, in Japan there are 16, in Europe 10, in 
Sweden 9, in Iceland and in Central Spain 8. The general 
result seems to be that those regions which are very rich in their 
total number of plants require a larger number of their pre- 
ponderant orders to make up half the total flora ; which implies 
that they have a larger proportion of orders which are approxi- 
mately equal in number of species. 

Another mode of comparison is to give the names of the 
first three or four, or even ten or twelve, of the orders which 
have the greatest number of species. It is found, for example, 
that in equatorial regions LeguminossB usually come first, 
though sometimes Orchids are most abundant ; in temperate 
regions the Composites or the Grasses; and in the Arctic, 
Grasses, followed by Crucifera? and Saxifrages. A few of the 
tables constructed by De Candolle are given as examples. 

British Guiaxa ( Scliomburgh ) 

3254 species 

Leguminosae 469 species 

Orchidese 214 " 

Rubiacege 176 " 

Melastomaceae 126 " 

The Andes of New Grenada (Humboldt) 

1041 species 

Composite 86 species 

Leguminosae 65 " ' 

Rubiacese 49 " 

Graminese 42 " 

Orchidese .it,,. • 41 " 



DISTKIBUTION OF SPECIES 



23 



Australia and Tasmania (R. Brown) 

4200 species 

Legiiminosse 
Euphorbiacese 
Compositae 
Orchidese 



Cyperaceae 
Giaminese 
Myrtaceaj 
Proteacese 



Iceland. 

1. Cyperaceae 47 

2. Graminese 45 

3. Compositae 24 

4. Caryophylleae 23 

5. Cruciferae 21 

6. Amentaceae 20 



402 species 

7. Saxifrageae 15 

8. Rosaceae 15 

9. Ericaceae 12 

10. Juncaceae 12 

11. Ranunculaceae 11 

12. Polygoneae 11 



As a short general conclusion De Candolle says: 



The Leguminosae 
The Composites , 
The Grasses . . 



. . dislike cold. 
, . dislike cold and wet. 
dislike drought. 



Other examples will be given when discussing the compara- 
tive relations of the various temperate and tropical floras of 
the world. 



CHAPTER III 

THE NUMEEICAL DISTRIBUTION OF BRITISH PLANTS I TEMPERATE 

FLORAS COMPARED 

Proceeding from the more to tlie less familiar regions we 
will be^rin witli a few of the facts as to the flora of our own 
country. Partly owing to its insular character, and also be- 
cause it has few lofty mountains or extensive forests, the num- 
ber of species of flowering plants is somewhat (but not much) 
below that of most continental countries of equal area. It con- 
tains about 1800 species, as a rough mean between the estimates 
of dift'erent botanists.^ It may seem curious that there should 
be any such difference of opinion, but one of the facts that 
have alwa^^s been adduced as showing that species are not fixed 
and immutable entities is the frequent occurrence of varieties, 
which are sometimes so peculiar and so apparently constant 
that they are treated by some botanists as distinct species, by 
others as sub-species, and by others again as forms or varieties 
only. These modifications of a species are usually confined to 
a more limited area than the species itself, and are occasionally 
connected with each other or with the parent species by inter- 
mediate forms. Again, when these varieties are cultivated, 
and esjDecially when a large number of plants are raised from 
their seeds, they are apt to revert partially or wholly to the 
parent form. Another source of difference of opinion among 
botanists is, as to the treatment of those plants, found usually 
near human habitations, which are supposed to have been orig- 
inally introduced, either purposely or accidentally, from foreign 
coimtrios. Such are the wild Larks])ur and Monkshood, the 

1 In all the tables and comparisons of " Ploras " in this work, unless 
where ferns are specially noted, flowering plants only are intended, even 
when the term '* plants " is used. 

24 



TEMPERATE FLORAS 



25 



Red Valerian, the Balm, the Martagon Lily, and many others. 
This explanation is necessary in order to avoid any supposition 
of positive error when the figures here given do not agree 
with those of anv of the text-books or local floras. 

xJ 

The chief diiferences arise, however, from the increased 
study of certain difficult groups leading to the separation of 
large numbers of slightly differing forms, that hardly any 
one but an expert can distinguish, as distinct species. The 
most important of these are the Brambles (the genus Rubus) 
and the Ilawkweeds (the genus Hieracium). During the last 
thirty years the numbers of these have more than doubled, 
according to the standard authority for British botanists — 
The London Catalogue of British Plants. The numbers in 
an early and late edition are as follows : — 



Genus. 


7th Ed., 1877. 


lOth Ed., 1908. 


Rubus 


54 species 
48 

1 

1 


116 species 
133 " 


Hieracium 


Euphrasia 


15 


Rhinanthus 


8 " 







In the last two cases two well-known plants — the little 
" eyebright " of our turfy banks, and the '' yellow rattle " of 
peaty meadows, which have been each considered to form a 
single species from the time of Linnseus to that of Bentham 
and Hooker — are now subdivided into a number of distinct 
species, each claimed to be well recognisable and constant. 
With such rapid changes in the estimate of species in so 
well-known a flora as our own it may be thought that the 
number of species in foreign countries is even more uncertain. 
This, however, is by no means the case, as tlio great 
majority of the species of plants a^ well as of animals; offer 
little difficulty, and present few fixed varieties (though 
abundance of variation), so that for general comparisons the 



D. H. HILL LIBRARY 



26 THE WORLD OF LIFE 

figures obtainable are very fair approximations, and give us 
interesting and valuable information. 

About one-third of the total numbe'r of our species of 
wild flowering plants belong to what the late Mr. H. C. Watson 
termed the British type ; that is, they are found in suitable 
places over the whole of Great Britain, and in most districts 
are so plentiful that they may be termed common plants — 
such are the Alder, Birch, and Hazel among trees and shrubs ; 
the Honeysuckle, Ivy, Heather or Ling, Daisy, Chickweed, 
!N^ettle, and a host of others. Another gi'oup is abundant 
in England, but absent from the Highlands or from Scotland 
generally, such as the Dwarf Gorse and Yellow Dead-Nettle. 
Several arctic or alpine plants are peculiar to the Highlands, 
a considerable number of species are found only in our 
eastern counties, while as many or more are characteristic of 
the west. 

More curious perhaps than all these are the cases of 
plants found only in one small area, or two or three isolated 
patches ; and of others which are limited to a single station, 
sometimes of a few acres or even a few yards in extent. 
Such are the Cotoneaster, found only on Great Orme's Head 
in ]^. Wales; the Yellow Whitlow-Grass, on Worms Head 
in S. Wales ; the pretty white-flowered Potentilla rupestres, 
on a single mountain-top in Montgomeryshire; the small 
liliaceous plant, Simetlius hicolor, in a single grove of pine 
trees near Bournemouth, now probably exterminated by the 
builder, and another plant of the same family, Lloydia 
serotina, limited to a few spots in the Snowdon range ; the 
beautiful alpine Gentiana verna, in upper Teesdale, Yorkshire, 
and others confined to single mountains in the Highlands. 
Between the extremes of widespread abundance and the 
greatest rarity, every intermediate condition is found ; and 
this is, so far as we know, a characteristic of every part of 
the world. This, again, affords a striking proof of that 
struggle for existence which has already been referred to, 
acting, as Darwin was the first to point out; first to limit the 



TEMPEEATE FLOKAS 



27 



range of a species, often so that it exists only in two more or 
less isolated areas, then to diminish the number of individuals 
in these areas, and finally to reduce them to a single group 
which ultimately succumbs to an increased stress of competi- 
tion or of adverse climatal changes, when a species which 
may have once been flourishing and widespread akogether 
ceases to exist. The rarity of a species may thus be 
considered as an indication of approaching extinction. 

Numerical Distribution of Plants hi Britain 

We will now give a few numerical statements as to the 
comparative abundance of the species of plants in large and 
small areas in various parts of the world, such facts having a 
special application to the theory of evolution. The 55 
counties of England and Wales (counting the three Ridings 
of Yorkshire as counties) have usually areas from 500 to 
2500 square miles; and a considerable number of them 
have had their plants enumerated in special catalogues or 
floras. The following are the approximate numbers of the 
flowering plants in a few of these : — 



Statistics of County Floras 




County. 


Area, Sq. Miles. 


No. of Species. 


Carnarvonshire 


563 
1357 

980 
1533 

790 
1612 

840 

636 
1519 
2638 

233 
2658 


1056 


Cornwall 


1140 


Dorsetshire 


1010 


Essex 


1010 


Glamorganshire 


950 


Hampshire 


1150 


Herefordshire 


865 


Hertfordshire 


890 


Kent 


1120 


Lincolnshire 


1200 


Middlesex 


835 


West Yorkshire 


995 


Mean of the 12 counties 


1198 


1026 


Great Britain 


87,500 


1800 







28 



THE WOELD OF LIFE 



This table of the distribution of plants in our counties 
is very instructive, because it shows us the influence of 
diversity of soils on the number of species that can grow 
and maintain themselves naturally as wild plants. This is 
largely dependent on the extreme diversity of the geology of 
our island, almost every geological formation from the oldest 
to the most recent being rej^resented in it. This variety of 
soil seems to be much more important than diversity of sur- 
face due to altitude, so that our lowland counties are quite 
as rich as those which are hilly or mountainous. Again, we 
see that, within moderate limits, greater area has little in- 
fluence on richness of the flora, the largest. West Yorkshire, 
having only about one-fifth more species than the smallest, 
Middlesex, with only about one-twelfth the area. 

The preponderating importance of variety of soil and sur- 
face conditions affording good stations for plants, such as 
woods, hedgerows, streams, bogs, etc., is well shown by a few 
special comparisons that have been made by experienced 
botanists. 

The Parish of Cadney (Lincolnshire), a little over 3 square 
miles in area, has 720 species of flowering plants; the county 
nearly 900 times as large, having 1200. 

The Parish of Edmondsham (in Dorsetshire), covering less 
than 3 square miles, has 640 species ; the county, 340 times 
as large, having 1010 species. 

An equally remarkable instance was given by Mr. H. C. 
Watson fifty years ago, and no doubt from his own observa- 
tions, as he resided in the countv. 





Area, 


Sq. Miles. 


Species. 


Surrey 




760 
60 
10 

1 


840 


An area in Surrey of 


660 




600 


" at Thames Ditton, Surrey. • - 


400 



TEMPEEATE FLOIUVS 29 

Here we see that 10 square miles coutaiiied nearly as many 
species as 60, and nearly two-thirds the nmiibcr in TOO square 
miles ; while the single square mile produced nearly half the 
number in the whole county. 

Taking still smaller areas, Mr. Woodruffe-Peacock found 
fields in Lincolnshire and Leicestershire, of from 10 to 25 
acres, to yield from 50 to 60 species of plants ; while a plot 
of 16 Vo feet square (or 1 perch) would usually have 20 to .')0 
species. Old and long-disused stone-quarries are often very 
rich, one of about two acres producing sometimes as many 
species as the fields of eight or ten times the area. On a plot 
of turf 3 feet by 4, at Down in Kent, Mr. Danvin found 20 
species of flowering plants growing. 

These facts of the distribution of plants in our own is- 
lands prove, that for moderately large areas in the same 
country possessing considerable diversity of soil and general 
conditions affecting plant-life, the majority of the species are, 
as a rule, so widely scattered over it that approximately similar 
areas produce a nearly equal number of species. Further, 
we find that areas of successively smaller and smaller sizes have 
a very much greater number of species relatively than larger 
ones ; so that, as we have seen, 10 square miles may show al- 
most as much variety in its plant-life as an adjacent area 
of 60 square miles, and that a single square mile may some- 
times contain half the number of species foimd in 700 square 
miles. 

This characteristic of many small areas being often much 
richer in proportion to area than larger ones of which they 
form a part, is a necessary result of the great differences in 
the areas occupied by the several species and the numbers 
of the individuals of each ; from those very common ones which 
occur abundantly over the whole country, to others which, al- 
though widespread, are thinly scattered in favourable situa- 
tions, down to those exceptional rarities which occur in a very 
few spots or in very small numbers. Those spots or small 
areas which present the most favourable conditions for plant- 



30 THE WORLD OF LIFE 

life and are also most varied in soil, contour, water-supply, 
etc., will, when in a state of nature, be occupied by a large 
proportion of the common and widespread plants, together 
with so many of the less common or the rare species which 
find the requisite conditions in some part of its varied soil 
and aspects, as to produce that crowding together of species 
and luxuriance of growth which are such a joy to the botanist 
as well as to the less instructed lover of nature. 

All these peculiarities of vegetation are to be met with in 
every part of the world, and often in a more marked degree 
than with us. But this depends very much on diversities of 
climate and on the extent of land surface on which the entire 
flora has been developed. The total number of species de- 
pends mainly on these two factors, and especially on the 
former. The variety of species is small in arctic or sub-arctic 
lands, where the long and severe winter allows of only certain 
forms of vegetable and animal life; and it is equally if not 
more limited in those desert regions caused by the scarcity 
or almost complete absence of streams and of rain. It is most 
luxuriant and most varied in that portion of the tropics where 
the temperature is high and uniform and the supply of mois- 
ture large and constant, conditions which are found at their 
maximum in the Equatorial Zone within twelve or fifteen 
degrees on each side of the equator, but sometimes extend- 
ing to beyond the northern tropic, as on the flanks of the 
Himalavas in north-eastern India, where the monsoon winds 
carrv so much moisture from the heated Indian Ocean as to 
produce forests of tropical luxuriance in latitudes where most 
other parts of the world are more or less arid, and very often 
absolute deserts. 

Temperate Floras compared 

I will now endeavour to compare some of the chief floras 
of the Temperate Zone, both as regards the total number of 
species in fairly comparable areas, and the slight but clearly 



TEMPERATE FLOEAS 



oi 



marked increase of the number in more southern as compared 
with more northern latitudes. 

I will first show how this law applies even in the com- 
paratively slight difference of latitude and climate within our 
own country. Dividing Great Britain (without Wales) ^ into 
three nearly equal portions — Scotland north of the Forth and 
Clyde, Mid-Britain, and South Britain, including all the 
southern counties; with areas of 22,000, 26,000, and 31,000 
square miles — the number of species (in 1870) was, respec- 
tively, 930, 1148, and 1230. At the same period the total of 
Great Britain was 1425 species. These figures are all ob- 
tained from Mr. H. C. Watson's Cybele Britannica, and must 
therefore be considered to be fairly comparable. We see here 
that the whole of the Scottish Highlands, with their rich alpine 
and sub-alpine flora, together with that of the sheltered valleys, 
lakes, and mountainous islands of the west coast, is yet de- 
cidedly less rich in species than Mid-Britain, while both are 
less rich than South Britain, with its more uniforai surface, 
but favoured with a more southern climate. 

The following table shows these facts more distinctly : — 





Area, 
Square Miles. 


No. of 
Species. 


North Britain 


22,325 
26,550 
31,050 


930 


Mid-Britain, Lowlands south to Stafford -^ 

and Leicester J 

South Britain ( Wales excluded ) 


1148 
1230 







The above figures have been kindly extracted from Wat- 
son's volume by my friend the late Mr. W. H. Beeby. 

Making a comparison of some countries of Europe we have 
similar results more clearly shown. 

1 Wales is omitted in order to make the three divisions more equal, and 
contrasted in latitude only. 



32 



THE WOELD OE LIEE 



Floras of Europe, showing Influence of Latitude 



Countries. 



Europe 

Lapland 

Scandinavia and 
Denmark . . . . 

Sweden 

Britain 

Germany 

Switzerland . . . 

France 

Italy 

Sardinia 

Sicily 



Area. 
Square Miles. 



No. of 
Species. 



;3,850,000 
150,000 
456,000 

173,000 

87,500 

208,000 

16,000 

204,000 

91,400 

9,300 

9,940 



9500 

500 

1677 

1165 
1860 
2547 
2454 
4260 
4350 
1770 
2070 



Nyman 

A. De Candolle 



(( 



Lend. Cat., 1895 

Garehe, 1908 

Schinz and Kellar, 1908 

Coste, 1906 

Beccari 



The above table shows us a continuous and well-marked 
increase as we go from north to south, the irregularities in 
this increase being well accounted for bj local conditions and 
by allowing something for differences of area. Sweden is so 
much poorer than Britain, owing to its having been completely 
ice-clad during the glacial epoch, while much of southern Brit- 
ain was free. Gennany is poorer than Erance, partly on 
account of its severer continental climate, but also owing to 
Erance possessing a greater variety of surface, owing to its 
including a portion of the loftiest Alps in the south-east, the 
isolated Pyrenees in the south, the Jura and Vosges mountains 
on the north-east, and its central volcanic ranges, together with 
its southern Mediterranean coast, and a very extensive west- 
ern and northern coast-line. It also has a more diversified 
soil, owing to far less of its surface being buried under glacial 
debris. Italy has still greater advantages of a similar kind, 
and its slight superiority to Erance, with less than half the 
area, is about what we should expect. It well illustrates the 
fact, already ascertained, that difference of area within moder- 
ate limits is of far less importance than comparatively slight 
advantages in soil and climate. 



TEMPERATE ELOEAS 



33 



Turning now to N'orth America, the following figures from 
the latest authorities have been supplied by my friend Mr. 
J. D. A. Cockerell : — 



state. 



Montana and Yellowstone 

Park 

Nebraska 

Colorado 

California 



Area, 
Square Miles. 



150,000 

118,000 
104,000 
158,000 



No. of 
Species. 



1934 

1478 
2872 
2700 



Remarks. 



Data in 1900 

1898 
1900 
" recent 



Two subdivisions of the eastern United States show well the effects 

of latitude. 



Central and north-east ~ 
States — Michigan to L 


736,000 


32r98 


Recent estimate 


Virginia, Kentucky 

South-east United States .... 


630,000 


6321 


et (( 



The number of species in proportion to area and position 
is apparently less than in Europe, though the corresponding 
latitudes are farther south. Germany and Switzerland com- 
bined, with an area less than one-third of the north-eastern 
and central States, have about as many species ; while Erance, 
in about the same average latitude, but with less than one- 
third the area, has considerably more. The south-eastern 
States extending to 30° S. lat. have about the same number 
of species as Europe from the Alps and Carpathians south- 
ward, while the area of the latter is very much smaller and 
its latitude about eight degrees farther north. 

The whole Mediterranean flora was estimated bv Griesbach 
and Tchikatcheff, in 1875, to comprise 7000 species in an area 
of about 550,000 square miles ; so that the best comparisons 
that we can make between large European and American areas 
show a decided superiority in the former. This is no doubt 
partly due to the much severer winter climate in correspond- 
ing latitudes of !N'orth America ; and perhaps the long per- 



84 THE WORLD OE LIFE 

sistence of siicli conditions before the glacial period may be 
the main cause of the whole phenomenon. 

It is, however, in temperate Asia that we find what seem 
to be the richest extra-tropical floras, at least in the north- 
ern hemisphere. The great work of Boissier, Elora Orientalis 
(1880), describes 11,876 species in the region of East Europe 
and South- West Asia, from Greece to Afghanistan inclusive, 
the area of which may be roughly estimated at 2,000,000 
square miles. It is a region of mountains and deserts inter- 
mingled wdth luxuriant valleys and plains, and almost trop- 
ically warm in its southern portion. So much of it is diffi- 
cult of access, however, that the collections hitherto made 
must fall far short of being complete. Its extreme richness 
in certain groups of plants is showm by the fact that Boissier 
describes 757 species of Astragalus or Milk-vetch, a genus of 
dwarf plants spread over the w^hole northern hemisphere, but 
nowhere so abundant as in this region. Europe has 120 
species. • 

The only other extensive area in temperate Asia the plants 
of which have been largely collected and recently catalogued 
(by Mr. W. B. Ilemsley of the Kew Herbarium) is China 
and Corea, occupying a little more than 1% million square 
miles. The enumeration, completed in 1905, shows 8200 
species of flow^ering plants actually described. But as large 
portions of this area have never been visited by botanists, 
and as new species w^re still flowing in rapidly at the close 
of the enumeration, there can be little doubt that the total 
will reach, before many years have elapsed, 10,000 or per- 
haps 12,000 species. It is, moreover, an area that is es- 
pecially rich in trees and shrubs, and as these are less col- 
lected by the travelling botanist than the herbaceous plants, 
it becomes still less easy to speculate on the actual number 
of species this country really contains. Japan, which is prob- 
ably better known, has about 4000 species in less than one- 
tenth the area, and is thus a little richer than Erance. It 



TEMPERATE ELOEAS 35 

agrees, however, very closely with the AVestern Himalayas as 
estimated by Sir J. D. Hooker. 

Coming to the southern hemisphere, we find several ex- 
amples of exceedingly rich floras. The first to be noticed is 
Chile, where, in an area of 250,000 square miles, 5200 species 
of flowering plants have been found. In Australia, Xew South 
Wales, with an approximately equal area, has 3105 species, 
while West Australia has 3242 species in what is probably 
not more than one-fourth the area, as so much of that Colony 
is absolute desert. 

But richer than either of these is extra-tropical South 
Africa, where, in about a million square miles, 13,000 species 
are known, and there are still probably many to be added. 
The richest portion of this area is the Cape Eegion, as de- 
fined by Mr. H. Bolus, where, in 30,000 square miles, there 
are about 4500 species of flowering plants. This area is the 
same as that of southern Britain, and about one-third that of 
West Australia excluding the tropical portions and the desert. 

All these rich areas in the southern hemisphere agree in 
one respect, they are limited inland hj mountains or deserts, 
and their coast-line is bordered by a considerable extent of 
sea less than 1000 fathoms deep, and another still larger 
extent under 2000 fathoms. There is thus a high prob- 
ability that in all these cases the flora was originally 
developed in a much larger and more varied area, and that 
it has been, in comparatively recent times, very greatly re- 
duced in extent, thus crowding the various species together. 
This has, no doubt, caused the extinction of some, while 
others show that they are on the road to extinction by their 
limitation to very narrow areas, as is especially the case with 
many of the orchids, the heaths, and other characteristic 
South African groups. Of course the mere submergence of 
a large amount of lowlands would not, of itself, enable any 
of its plants to invade the adjacent undisturbed land; but 
the subsidence would no doubt have been very slow, and 



36 



THE WOELD OE LIFE 



might have included the degradation of lofty mountains. 

It Avould also be accompanied by a lowering of some of the 
existing area. This would modify the climate in various 
ways, leading probably to a higher temperature and more 
moisture, thus giving more favourable conditions generally 
for a great variety of plants. 

For easy reference it may be well to give here a table 
showing the main facts as to these warm-temperate floras. 

Warm-Temperate Floras compared 
Northern Hemisphere 



Country. 



S.E. United States. 

Mediterranean 

Greece to -j 

Afghanistan j 

China and Corea. . . 

Japan 

Himalayas, West. . . 
Algeria 



Area, 
Square Miles. 



630,000 
550,000 

2,000,000 

1,500,000 
150,000 
150,000 
150,000 



No. of 
Species. 



6,321 
7,000 

11,876 

8,200 
4,000 
4,000 
2,930 



T. D. A. Coekerell 
Tchikateheff 

Boissier, Flora 
talis, 1880 
Hemsley, 1905 
Havati, 1908 
Hooker, 1906 
Matthews, 1880 



{ 



Orien- 



Chile 


Souther 

250,000 
310,700 

? 90,000 

88,000 

26,380 

103,650 

1,000,000 

30,000 


n Eemiepheri 

5,200 
3,105 

3,242 

1,830 

965 

1,474 

13,000 

4,500 


? 

• 


N.S. Wales 

W. Australia 

Victoria 


Miiller 

r " (tropics and 
\ deserts omitted ) 

Miiller 


Tasmania 


ii 


New Zealand 

South Africa 

The Cape Region . . 


Cheeseman, 1906 
Thomer's Census 
H. Bolus, 1886 



Temperate Floras of Smaller Areas compared 

We will now deal with a series of smaller areas (com- 
parable to our counties) which I have been able to collect 
from various parts of the world ; and I propose to arrange 
them in order of latitude, from north to south, so as to show 
still more distinctly the influence of climate. Each main 



TEMPERATE ELOEAS 



37 



division of the globe will be considered separately for 
convenience of reference, and we begin with Europe, for wbicli 
materials are the most accessible, though still far from abun- 
dant. 

The recent publication of a flora of Harjedal, a province 
of central Sweden, with a mountainous surface and abundant 
forests, shows how poor is a sub-arctic area which has 
recently been buried under an ice-sheet. The real wonder is 
that it should have acquired so rich a flora by the natural 
means of dispersal from more southern lands. 



Temperate Floras of Small Areas in Europe 



Locality. 






I 

C 
< 

a, 



Harjedal (Sweden), lat. 61°-64' 

Malvern Hills 

Hertford (near) 

Strasburg, lat. 48 J ° 

Schaflniiausen 

Thurgau 

Basel 

Zurich 

St. Gallen 

r Schwyz, Uri, Underwalden , 

< Glarus 

I Uri 

r Grisons , 

^ Valais, 464° 

tTicino, 46J° 

Ofengebietes, Grisons 

Vallee de Joiix, Jura , 

Bergunerstocke, Engadine 

Poschiavo, S. of Bernina Pass ... 

Euganean Hills, Padua 

Susa, Piedmont (Beccari) 

Ferrara, Valley of Po (Beccari) 

Mytilene (Lesbos) (Candargy) . . 



Area, 
Sq. Miles. 


No. of 
Species. 


5375 


606 


120 


802 


80 


810 


120 


960 


114 


1220 


381 


1006 


163 


1117 


666 


1151 


779 


1295 


950 


1352 


267 


1100 


415 


1160 


2773 


1550 


2027 


1752 


1088 


1504 


86 


797 


100 


823 


47 


873 


92 


1200 


795 


1400 


540 


2203 


1012 


794 


675 


1249 



Remarks. 



Birger. 1908 

De Candolle 
(( 

a 

H. H. Field 

(( 
it 
it 
it 
it 
it 
it 

a 

Lat. 46°40' 
Lat. 46°40' 
Lat. 46°30' 
46°20' 
45°30' 
45° 10' 
44°50' 
39°00' 



(I am indebted to Mr. Herbert H. Field for all the data 
in this table, except where otherwise stated. They are from 



38 THE WOELD OF LIFE 

the original authorities, and he has kindly brought them 
up to date as far as possible, so that they may be fairly com- 
parable.) 

Although very unequal in extent, the various Swiss 
cantons, which form the bulk of this table, are remarkably 
similar in their botanical riches, the smallest, most northerly, 
and least alpine (Schaffhausen) having more than two-thirds 
the number of species of the Valais, the most southerly, 
nearly the largest, and the most alpine, the main chain of 
the Alps for nearly 100 miles forming its southern boundary, 
and the Bernese Alps its northern, But Schaffhausen geo- 
graphically connects eastern France wdth western Germany, 
and partakes of the rich flora of both countries. This table 
of the Swiss cantons is also very interesting in showing us 
that alpine floras are really no richer in species than those 
of the lowlands, if we compare approximately equal areas. 
A remarkable illustration of this is the comparison of the 
Ofengebietes, a district including snowy peaks, forests, and 
lowland meadows, having almost exactly the same number 
of species as an equal area near Strasburg, or one around 
the town of ITertford ! Switzerland, thouirh so verv unlike 
Great Britain in situation, climate, and physical conditions 
generally, yet reproduces in its cantons that curious uni- 
formity in species-production that we found to be the case 
in our counties. But as Switzerland, though only one-fifth 
of our area, has a gTeater number of species by one-third, 
that superiority is, as a rule, reproduced in its subdivisions. 
Susa, in Piedmont, wdth its fertile valleys and snowy Alps, 
has by far the richest flora of the whole series, due to its 
w^arm climate, variety of surface, and complete shelter from 
the north. Mytilene, the farthest south, has doubtless been 
impoverished botanically by its large population and extensive 
fruit culture. 

It is, I think, clear that, other things being equal, an 
alpine flora is not at all richer than a lowland one ; but, as 
we shall see further on, there are indications that the high 



TEMPERATE FLORAS 39 

alpine flora really partakes of that poverty wliicli appertains 
to liigii latitudes. It is the novelty and beauty of alpine 
plants that are so attractive to the botanist and so entrancing 
to the lover of nature, that give an impression of abundance 
which is to some extent deceptive, and this is increased by 
the fact that Avhole groups of plants which are more or less 
rare in the lowlands are plentiful at higher altitudes. Two 
other circumstances add to this impression of abundance — 
alpine flowers are mostly very dwarf, and being all at the 
same level, attract the eye more than when distributed over 
various heights from that of the creeping herb to the summit 
of lofty trees ; and, in addition to this, the shortness of the 
season of growth leads to a much larger proportion of the 
species flowering together than on the lowlands at the same 
latitude. 

Extra-European Temperate Floras 

The number of floras which are available for comparison 
with those of Europe are few in number and yqxj widely 
scattered ; but they serve to illustrate the fact already dwelt 
upon, that the dift'erences of species-j^opulation in fairly com- 
parable areas approach to a general uniformity all over the 
world. 

Boulder County is probably one of the most favourably 
situated areas in the United States. It is onlv a little west 
of the centre of the country; it comprises warm valleys and 
one of the highest of the Rocky Mountain summits. Long's 
Peak, and being in the latitude of southern Italy and Greece, 
has abundant sunshine and a warm summer temperature. 
It thus agrees in physical conditions with some of the alpine 
cantons of Switzerland, and the number of its flowering 
plants is almost identical with the average of Zurich, St. Gall, 
Schwyz, etc., which have almost the same mean area. 

Washington, D.C., with an undulating surface just above 
the sea-level, and a fair amount of forest and river-swamp, 
agrees very well with the mean of Strasburg and Schaff- 



40 



THE WOKLD OF LIFE 



Extra-European Temperate Floras. Small Areas. 



Lat. 



40°N. 
39°N. 



37°N. 
37°N. 



35 °S. 

35*S. 

34°S. 

32rs. 

27rS. 

27J°N. 



Country. 



North America. 
Boulder Co., Colorado. . . 
Washington, D.C 

Japan. 

Mount Nikko 

Mount Fujiyama 

South Africa. 
Cape Peninsula 

Aust7nlia. 

Illawarra, N.S.W 

Cumberland Co., N.S.W. . 
Mudgee (Wellington Co.) 
Brisbane, Q 

North India. 
Temperate Sikhim 



Area 
Sq. Miles. 



751 
108 

360 
520 

197 

200 

1400 

600 

800 

1800 



No. of 
Species. 



1200 
922 

800 
730 

1750 

829 
1213 

631 
1283 

2000 



Remarks. 



Cockerell 
Ward 

Hayati 

Bolus 

A. G. Hamilton 
W. Woolls 
A. G. Hamilton 
Jas. Wedd 

Hooker 



liausen, somewhat similarly situated, but at a higher latitude. 

The two mountain areas in Japan, which Mr. Hajati 
informs me have been well explored, show an unexpected 
poverty in species, being much below any of the Swiss cantons 
of equal area. This is the more remarkable as Japan itself 
is equal to the most favoured countries in Europe — France 
and Italy; and this again indicates the combined effect of 
altitude and insularity in diminishing species-production, the 
lower parts of these Japan mountains being highly cultivated. 

In the southern hemisphere we come first to the Cape 
Peninsula, as limited by Mr. Bolus, and often thought 
to be the richest area of its size in the world. There are 80 
species of heaths and nearly 100 species of orchises in this 
small tract only a little larger than the Isle of Wight. 'No 
other similar area in the temperate zone approaches it, 
though it is possible that an equally rich area of the same 
extent might be found in temperate Sikhim, where several 



TEMPEEATE ELOEAS 41 

distinct floras meet and intermingle. But as the Valais is 
nearly as rich as Sikhim, and Susa with one-fourth the area 
is still richer^ it is quite possible that smaller areas may 
be found as rich as that of the Cape Peninsula. The best 
third of the Susa district would probably approach closely 
if it did not quite equal it. Temperate Australia is another 
country which has obtained a high reputation for its floral 
riches, for much the same reason as the Cape of Good Hope. 
In 1810 Robert Brown made known the extreme interest 
of the Australian flora, both from its numerous hitherto un- 
known types of vegetation and the variety and beauty of its 
flowering shrubs. It was therefore supposed that the country 
was not only botanically rich in new species and genera, but 
actually so in the number of its species in proportion to area, 
and this may really be the case with limited portions of West 
Australia (for which I have been able to obtain no detailed 
information), but is certainly not the case for Xew South 
Wales, Victoria, or Tasmania. Cumberland County, which 
contains Sydney and the celebrated Botany Bay, is only a 
little richer than our counties of about the same area, while 
the celebrated district of Illawarra only produces about the 
same number of plants as does Middlesex, which has, ex- 
clusive of London, a less area. Many parts of Europe in a 
similar latitude are much more productive. 

There is, however, one world-wide group of plants in 
which, as regards small areas, eastern temperate Australia 
seems to be pre-eminent — that of terrestrial Orchids. Mr. 
H. Bolus, in his work on the Orchids of the Cape Peninsula, 
states that there are 102 species in an area of 197 square 
miles ; and he quotes Mr. Eitzgerald, the authority on the 
Orchids of Australia, that " within the radius of a mile '' he 
remarks, " certainly no such concentration would be found 
on the Cape Peninsula." I think it probable that the 
" radius of a mile '' is meant a mile bevond the citv and 
suburbs of Svdnev, in which case it mio'ht bo an area of 
from 10 to 20 square miles. Or it might mean a picked 



42 THE WORLD OF LIFE 

area of about 4 square miles of uncultivated land some miles 
away. That this latter is quite possible is shown by my 
friend Mr. Henry Deane, who has for many years studied 
the flora of 20 square miles of country around Hunter's Hill, 
on the Paramatta Kiver, to the north-west of Sydney, and he 
here obtained 59 species of Orchids out of a total of 618 
flowering plants. The sequence of the first eight orders in 
number of species is as follows : — 



1. Orchidese 51) 

2. Myrtaceae 5.5 

3. Leguminosse 53 

4. Pioteacese 35 



5. Compositae 32 

6. Graminese 31 

7. Cyperacese 30 

8. Epacridese 25 



In XcAv South Wales, as a Avhole, Leguminosse are first 
and Orchids fifth in order. There is probably no other 
purely temperate flora in which Orchids so distinctly take 
the first place as in the vicinity of Sydney. 

The contrast in the numbers of species, in approximately 
comparable areas, between these two groups of waiTQ-temperate 
floras is fairly well marked throughout, there being, with few 
exceptions, a decided preponderance in the southern hemis- 
phere. South Africa is undoubtedly richer than China, though 
its area is less ; and perhaps than the oriental region of Bois- 
sier; Avhile Chili compares favourably with Japan or the West- 
ern Himalayas. Still, the differences are not very pronounced, 
and are such as appear due to their past history rather than to 
any existing conditions. Those in the northern hemisphere 
(except perhaps in the case of the Mediterranean coasts) have 
probably been for a considerable period stationary or expand- 
ing; while those in the south have almost certainly been far 
more extensive, and in later geological time have been contrac- 
ting, and thus crowding many species together, as already ex- 
plained. 



CHAPTER IV 

TJIE TEOPICAL FLORAS OF THE WORLD 

Although the idea of the tropics is always associated with 
that of a grand develojiment of luxuriant vegetation, yet this 
characteristic by no means applies to the whole of it, and 
the inter-tropical zone presents almost as much diversity in 
this respect as the temperate or even the frigid zones. This 
diversity is due almost wholly to the unequal and even er- 
ratic distribution of rainfall, and this again is dependent on 
the winds, the ocean currents, and the distribution and ele- 
vation of the great land masses of the earth. 

Once a year at each tropic the sun at noon is vertical for 
a longer period continuously tlian in any other latitude, and 
this, combined with the more complex causes above referred 
to, seems to have produced that more or less continuous belt of 
deserts that occurs all round the globe in the vicinity of those 
two lines, but often extending as far into the tropics as into 
the temperate zone. In a few cases similar conditions occur 
so near the equator as to be very difficult of explanation. It 
will be instructive to review briefly these arid regions, since 
they must have had considerable influence in determining 
the character of the tropical vegetation in their vicinity. 
Beginning with the Sahara, pre-eminently the great desert 
of our globe, if we take it with its extension across Arabia, 
we find that it occupies an area nearly equal to the whole 
of Europe, and that the African portion extends as far to 
the south as to the north of tlie tropic of Cancer. It thus 
eats away, as it were, a great slice of what in other continents 
is covered with tropical vegetation, and forms a vast barrier 
separating the tropical and temperate floras, such as exists 

43 



44 THE WORLD OF LIFE 

in no other part of the world. Passing eastward, the desert 
regions of Baluchistan, Tibet, and Mongolia are situated 
farther and farther north ; while abundant rainfalls and a 
truly tropical vegetation extend far beyond the tropic into 
what is geographically the temperate zone. This is especially 
the case along the southern slopes of the Himalayas and their 
extension into Burma and southern China. 

In the western hemisphere we have the desert regions of 
Utah, Arizona, and parts of northern Mexico all in the tem- 
perate zone. 

In the southern hemisphere the desert interior of central 
and western Australia reproduces the Sahara on a smaller 
scale. In Africa there is the Kalahari desert, mostly south 
of the tropic, but on the west coast extending to about 15° 
from the equator. In South America an arid belt of almost 
complete desert extends along the coast from near the equator 
to Coquimbo in Chili, whence crossing the Andes it stretches 
south-eastward into Patagonia. Even more extraordinary is 
the fact that in north-eastern Brazil, in the provinces of 
Ceara, Pernambuco, and Bahia, are considerable areas which 
have such small and uncertain rainfall as to be almost des- 
erts, and are practically uninhabitable. And this occurs 
only a few hundred miles beyond the great Amazonian forests 
of Maranham in 3° S. latitude. 

With the exception of these areas of very deficient rain- 
fall, it will, I believe, be found that the intertropical regions 
of the globe are the most productive in species of plants, 
and, further, that as we approach the equator, where the 
temperature becomes more uniform throughout the whole year 
and the amount of rain and of atmospheric moisture is also 
more evenly distributed, the variety of the species reaches 
a maximum. There is some evidence to show that this is 
the case not only in the region of the great forests, but also 
in those less humid portions which are more or less open 
country with a vegetation of scattered trees and shrubs, to- 
gether with herbaceous and bulbous plants which cover the 



i 



TEOPICAL FLORAS 



45 



ground only during the season of periodical rains, as will be 
shown later on. 

Tropical Floras — Large Areas 



Country. 



British India 

The Indian Peninsula 

Burma 

Indo-China 

Malay Peninsula 

Ceylon 

Java 

Philippines 

New Guinea 

Queensland 

Tropical Africa south of-* 

Sahara / 

Madagascar and Mascarenes. 

Central America and Mexico. 

Nicaragua to Panama 

Brazil 

Trinidad , 

Jamaica 



Area, 
Square 
Miles. 



No. of 
Species. 



1,300,000 

500,000 

172,000 

225,000 

35,000 

25,000 

50,000 
115,000 
310,000 

668,000 

6,500,000 
229,000 

910,000 

80,000 

3,200,000 

1,750 

4,200 



17,000 
4,500 
6,000 
7,000 
5,100 
2,800 

4,000? 

4,656 

6,000 

4,454 

18,300 
5,950 

12,000 
3,000 

22,800 
1,967 
2,720 



Authority. 



Sir J. D. Hooker 
Hooker 

Gagnepain 

Gamble 

Hooker 

Koorders 

Merrill 

Lauterbach 

Bailey 

Thonner's Census 
Thonner 

Hemsley 



Martius 

Harti 

Brittan 



The Tropical Flora of Asia 

As no part of the Asiatic continent (except the Malay 
Peninsula) approaches within eight degrees of the equator, its 
tropical area is very limited, barely reaching one and a quarter 
million square miles; and even if we add to it the whole of 
the Malay Archipelago, the Philippines, ^ew Guinea, and 
tropical Australia, it will not much exceed two millions. Yet 
these countries are in general so richly clothed with a tropical 
vegetation, that the actual number of their species will almost 

1 Mr. W, E. Broadway, who has collected in the island, informs me that 
some hundreds of species remain to be discovered in Trinidad. 



16 THE WORLD OF LIFE 

certainly surpass those of Africa, with three times their 
tropical area, and may approach, though I do not think they 
will equal, those of tropical America, or even of tropical 
South America only. Portions of this area have been well 
explored, especially the great peninsulas forming India 
proper, Burma, and Indo-China ; but the two latter are only 
sufficiently known to show their extreme richness botanically, 
and the same may be said of the numerous large islands of 
^ the Malay Archipelago. We may, I think, be certain that 
what is known of these two sub-regions is less than what re- 
mains to be made known. 

Sir Joseph Hooker estimates the whole flora of British. 
India at 17,000 species, including the desert flora of the Indus 
valley and the rich temperate and alpine floras of the 
Himalayas above an elevation of 6500 feet in the east and 
above 4000 or 5000 in the west. But as I am here dealing 
with tropical floras, it is only necessary for me to give such 
figures as are available for the specially tropical portions of 
it. 

The Indian Peninsula, bounded on the north by a curving 
line of hills and mountains which run not far from the line 
of the geographical tropic, is somewhat poor when compared 
with the aboundino: riches of Burma and Indo-China; vet it 
possesses areas, especially in the Western Ghats and the 
Xiigiris, of great botanical richness and beauty, much of which 
is still inadequately explored. Arid conditions prevail over 
much of its surface, both in the north and in the central 
plains, but these are interspersed w'ith deep moist valleys 
containing a vegetation allied to that of Assam. As a result 
of this greater aridity than that of the countries farther east, 
the peninsula is much poorer in Orchids, having only 200 
species against 700 in Burma ; but it has a great excess in 
Grasses, L^mbellifer?e, Labiatj:Te, and Boragine?e, and a cor- 
responding poverty in Melastomaceo?, Gesneracege, Myrtacese, 
Palms, and other more peculiarly tropical orders. 

Ceylon, though so closely connected with the peninsula, has 



TKOPICAL FLORAS 47 

a distinct flora, nearly 800 of its species and 23 of its genera 
being '^ endemic/' that is, wholly peculiar to it. It has much 
stronger affinities with the ]\ialayan flora, due in part, no 
doubt, to its moister and more uniform insular climate, but 
also to some features of its past history. 

The figures given in the table of the chief tropical floras 
of the world (p. 45) indicate, so far as possible, the actual 
numbers of the species now existing in collections, and, for 
purposes of comparison, require certain allowances to be 
made. 

Burma and Tndo-China are much less known than Penin- 
sular India, vet in a smaller area each has a considerably laro;er 
number of species ; while the Malay Peninsula, which is more 
completely forest-clad, is in proportion to its area still richer, 
due mainly to its more equable equatorial climate. The fol- 
lowinc: table of the chief natural orders is taken from Mr. 
Ilemsley's Introduction to the Flora of Mexico and Central 
America : — 

British Ixdia (17,000 species) 



1. Orchidere 1060 

2. I^giiiiiinosiE 831 

3. Glramineoe 800 

4. Robiacese 611 

5. Euphoibiacese 624 

6. Acanthaceae 503 



7. Compositae 598 

8. Cypeiaceaj 385 

0. Labiatae 331 

10. Urticaceae 305 

11. Asclepiadeae 249 

12. Rosaceae 218 



The sequence of the orders is taken from Sir J. Hooker's 
Sketch of the Flora of British India, a most interesting and 
instructive pamphlet published in 1906, but the numbers of 
species are inserted from Mr. Hemsley's work dated 1888. 
Since then the total numbers have increased from 13,647 to 
17,000, about one-fourth, so that the above figures will have 
to be increased in that proportion ; but they will have increased 
unequally, as shown by the fact that the orchids are estimated 
by Sir. T. Hooker at 1600. 

There is apparently no other extensive region as varied 
in soil and climate as British India, in which Orchids occu]\v 
the first place in the sequence of the orders. This is due to 



48 



THE WORLD OF LIFE 



their great numbers in Burma, but even more to the fact 
that in the whole range of the Himalayas epiphytic Orchids 
extend far into the temperate zone, while in the more eastern 
ranges they are pre-eminently abundant. This is well shown 
by the well-explored district of Sikhim, in which Orchids take 
the first place, not only in the tropical lowlands, but in the 
temperate zone from 6500 to 11,500 feet above the sea-level. 
It is possible that in some parts of the temperate Andes, wdiere 
Orchids are known to be extremely plentiful, the same pro- 
portion may exist ; but no such district appears to have been 
yet sufficiently explored by botanists. Before going further 
it will be as well to give the sequence of the orders in the 
districts already referred to. 

Tropical Sikhim (up to 6500 feet) (2000 species) 



1. Orchideae (1) 

2. Leguminosae (2) 

3. Gramineae (3) 

4. Urticacese (8) 

5. Euphorbiaceae (5) 



6. Cyperaceae (7) 

7. Rubiacese (4) 

8. Compositae (9) 

9. Aselepiadeae 

10. Acanthaceae (6) 



The numbers enclosed in brackets give the sequence in 
Burma, Avhich is very similar, except that Scitaminese (the 
Gingerworts) is the tenth order, while Asclepiadese is ex- 
cluded. 

The Malay Peninsula differs still more from the flora of 
north-eastern India, in being more exclusively equatorial and 
typical Malayan, and in this case I am able, through the kind 
assistance of Mr. J. T. Gamble, to give the number of species 
for the first twelve orders, which will be interesting for com- 
parison with others to be given further on. 

Malay Peninsula (5138 species) 



1. Orchidaceae 540 

2. Rubiaceae 312 

3. Leguminosae 266 

4. Euphorbiaceae 255 

5. Anonaceae 178 

6. Palmae 163 

Ferns 



7. Lauraceae 153 

8. Gramineae 144 

9. Zingiberaceae (Scitamineae) 137 

10. Gesneraceae 131 

11. Acanthaceae 128 

12. Cyperaceae 127 

368 species. 













Fig. 1. — Forest in Kelantan, jNIalay Peninsula. 



TROPICAL FLORAS 49 

This may be considered a typical Malayan flora of the low- 
lands, the mountains not being sufficiently extensive or lofty 
to favour the abundance of Composita' found in Sikhini and 
Burma; while the Anonacese (custard apples); the Lauracege 
(true laurels), producing cinnamon, cassia, and many other 
sj^ecies and odoriferous nuts, barks, and fruits, and, above 
all, the noble order of Palms, which have alwavs been con- 
sidered the most characteristic of the vegetable productions of 
the tropics, all take a higher place than in any part of India. 
Sir Joseph Hooker estimates the known, palms of Burma at 
68, so that it is hardly probable that any future additions 
will bring them to an equality with the much smaller Malay 
Peninsula. This affords another illustration of the increase 
in the number of species of Palms as we approach the equator, 
and renders them, with the Rubiacese, the Euphorbiacese, and 
the Orchids, the most typical of equatorial orders of plants. 

Through the kindness of Professor R. H. Yapp I am able 
to give here two beautiful photographs taken by himself in 
the Malayan forests, which give an excellent idea of the 
general character of the vegetation, though unfortunately not 
many of the trees or other plants shown can be identified; 
but a few remarks may be made as to their general charao- 
ter. 

Very prominent on the large trunk in the foreground is 
the bird's-nest fern (Asplenium nidus), very common in the 
forests and also in our hot-houses. Above it is a climbing 
fern (AcrosticJium scandens). On the left is a light-coloured 
slender tree with knobs or spines, and having many climbers 
about it. This may be a palm. 

Among the tangled vegetation in every direction are slender 
lines, upright, oblique, or beautifully curved; these are the 
lianas or forest-ropes, many being rattans (palms), but others 
belong to various dicotyledonous plants of many natural or- 
ders; and these form one of the most constant and charac- 
teristic features of the damp equatorial forests both in the 
eastern and western hemispheres. The slender shrub to the 



50 THE WOELD OF LIFE 

left, with a spray of foliage showing light against the dark 
trunk, may be an Ixora. On the left, crossing the spined 
trunk, is one of the climbing palms or rotangs (commonly 
called ^'rattan'' in England), while the dense mass of vege- 
tation to the right is largely composed of slender bamboos. 

The other view (Fig. 2) is more characteristic of the dense 
Malayan forest, where trees of all sizes, climbers of many 
kinds, and tangled undergrowth, of dwarf palms, shrubs, and 
herbs, fill up every spot on which plants can obtain a foot- 
ing. The large twisted climber in the foreground is perhaps 
a Bauhinia (Leguminosse), thougli it may belong to any of 
a variety of genera, and even orders, which form such ropes. 
The distinct ribbed leaf showing to the left of the most 
tw^isted part is probably one of the Melastomacege. The dwarf 
palms in the foreground are also very characteristic. Just 
above where the twisted climber goes out of sight is a climb- 
ing fern (Acrostichum scandens), and it seems to grow on 
a knobbed or spined trunk like the one in the other picture. 
A close examination will show that the five or six trunks 
of tall trees visible have each peculiarities of growth or of 
bark which prove tbem to belong to quite distinct species. 
The very straight one to the left of the rope-climber is a 
palm. The abundance of climbers is shown by the numerous 
very fine wdiite or black lines here and there crossing the 
picture, especially in the lower portion, each representing a 
liana or forest-cord striving to work its way upward to the 
light. In the original photograph the tangled mass of foliage 
in the foreground is seen to consist of a great variety of plants. 
The fern with very narrow fronds at the base of the rope is 
NepJu'oIejns cordifolia, while the large closely pinnate leaves 
in the foreground, as well as the smaller ones, truncate at 
the ends, are various species of palms. The prints, unfor- 
tunately, do not show all the details in the original photo- 
graphs. 

Professor O. Beccari, in the interesting volume on his ex- 
plorations in Borneo, tells us that when building a house 




Fig 2. — Forest in Perak. ^fal.iv Pcniiisiiln. 






TKOPICAL FLORAS 51 

on tlie Mattang inuunUiiii in Sarawak, three straight trees, 
each about 9 inches diameter, were found growing at such a 
distance and position as to be exactly suitable for three of 
the corner posts of the house in which he afterwards resided 
during some months' collecting there. When the tops were 
cut off, and he could examine them, he found them to be- 
long to three different genera of two natural orders, and also 
that they were all new species probably peculiar to Borneo. 
Another illustration he gives of the great productiveness of 
these forests in species of trees is, that in the two months 
he lived in his forest home he obtained fifty species of 
Dipterocarps (an order in which he was much, interested) in 
two months' collecting and within a mile of his house. This 
order of plants consists entirely of large forest-trees, and is 
especially characteristic of the true Malay flora from the 
Peninsula to Java, Celebes, and the Philippines. It is prob- 
ably at its maximum in Borneo, as Professor Beccari gives 
it as the twelfth in the sequence of orders as regards number 
of species: (1) Rubiace^e; (2) Orchidace^, 200 species; (3) 
Euphorbiaceee ; (4) Leguminosse; (5) Anonace^e; (6) Melas- 
tomacene; (7) Palmse, 130 species; (8) Urticacese; (9) 
Myrtacese; (10) Aracese; (11) Guttiferse; (12) Diptero- 
carpe?e, 60 species. This list, it must be remembered, refers 
to the '^ primeval forests " alone, taking no account of the 
widespread tropical flora found in old clearings and in the 
vicinity of towns and villages. 

Before leaving the Asiatic continent I must say a few words 
as to the figures given in the table for the plants of Indo- 
China, comprising the whole territory between Buraia aud 
China, which has been at least as w^ell explored by French 
botanists as have Burma and the Malay Peninsula by our- 
selves. Having been unable to obtain any statistical infor- 
mation on this area from English botanists, I applied to ]\r. 
Gagnepain, of the botanical department of the ^N^atural His- 
tory Museum of Paris, who hns kindly furnished me witli 
the following facts. They have at the Museum very large 



62 ' THE WORLD OF LIFE 

collections of 2)laiits from all parts of tliis territory, collected 
from 1862 onwards, but great numbers of the species are 
still undescribed. Only small portions of the Hora have been 
actually described in works still in process of publication ; but, 
from his knowledge of this extensive herbarium, he believes 
that the flora of Indo-China, as actually collected, comprises 
about 7000 species. 

Flora of the Malay Islands 

The great archipelago (usually termed the Malayan, or 
^' Malaisia "), which extends from Sumatra to Xew Guinea, 
a distance of nearly 4000 miles, and from the Philippines 
to Timor, more than 1000 miles, comprises an actual land 
area of 1,175,000 square miles, which is fully equal to that 
of all tropical Asia, even if we include the lower slopes of 
the Eastern Himalayas. Tliis great land-area has the advan- 
tage over the continent of being mainly situated within ten 
degrees on each side of the equator, and having all its coasts 
bathed and interpenetrated by the heated waters of the Indian 
and Pacific Oceans. These conditions have led to its being 
almost wholly forest-clad, and to its possessing a flora com- 
parable in luxuriance and beauty with that of the great 
Amazonian plain, situated almost exactly at its antipodes. 

The western half of this archipelago has undoubtedly 
been united with the continent at a comparatively recent 
geological epoch, and this portion of it, both in its animal 
and vegetable life, is nearly related to that of the Malay 
Peninsula and Siam ; but the three chief islands, Sumatra, 
Borneo, and Java, are of such great extent, and have such, 
differences, both of geological structure and of climate, as 
to give to each of them a distinct individuality, combined 
with, in all probability, a Avealth of species fully equal to 
that of the adjacent continent.^ The remainder of the Archi- 

1 The Director of Kew Gardens informs me that, in 1850, the flora of the ( 
" Netherlands India," extending from Sumatra to New Guinea but exclud- 
ing the Philippines, was estimated by the Dutch botanists to possess 0118 



TEOPICAL FLORAS 53 

pelago has bad, however, a different origin, and has been 
much longer isolated. Celebes and the Philippines have cer- 
tain features in common, indicating a remote but partial union 
with, or approximation to, the Asiatic continent, and probably 
subsequent submergence to an extent that has greatly impov- 
erished their mammalian fauna. Xew Guinea, however, 
stands alone, not only as the largest island in the world (ex- 
cluding Australia), but as, in some respects, the most remark- 
able, both by its extraordinary length of about 1500 miles, 
and its possession of a range of snow-capped and glaciated 
mountains. Biologically it is unique by having produced the 
wonderful paradise-birds, numbering about 50 species ; while 
its true land-birds already known amount to about 800 species, 
a number very far beyond tliat of any other island — Borneo, 
with its almost continental fauna, having about 450, and the 
great island-continent of Australia about 500. 

But, as regards plant-life, this vast archipelago is much less 
known than that of inter-tropical Asia, though it will, I believe, 
ultimately prove to be even richer. Of the two larger w-estern 
islands, Sumatra and Borneo, I can obtain no estimate of the 
botanical riches, and the same is the case with the whole of 
the Moluccas. Java is better known, but still inadequately. 
There remains for consideration the Philippines, Celebes, and 
^ew Guinea, as to which we have recent information of con- 
siderable interest. 

Since the Americans have established themselves in the 
Philippines they have done much to make known its natural 
products; and Mr. E. D. Merrill, botanist to the Bureau of 
Science at Manilla, has greatly increased our former scanty 
knowledge of its very interesting flora. He has been so kind 
as to send me several of his published papers, as well as a 
complete MS. list of the families and genera of vascular plants, 
with the number of species known to inhabit the islands up to 

species of flowering plants then known. As such large portions of all the 
islands are almost unknown botanically, it seems not improbable that the 
actual numbers may be three times as many. 



54 THE WORLD OF LIFE 

August 1909. This shows the large total of 4656 indigenous 
flowering plants already collected, though extensive areas in all 
the islands, and more especially in the great southern island 
Mindanao, are altogether unexplored. Besides these, there are 
no less than 791 ferns and their allies, a number which is 
probably not surpassed in any other country of equal extent 
and as imperfectly explored. The Malay Peninsula has rather 
more flowering plants, but its ferns are only 368, as given in 
]\rr. Eidley's list, issued in 1908. The following is the 
sequence for the first twelve orders (excluding introduced 
plants) from Mr. Merrill's lists: — 

Philippixes (4G56 species) 



1. Orchideffi 372 

2. Eubiacese 267 

3. Leguminosae 258 

4. Euphorbiacese 227 

5. Urticaceae, with ]\Ioraceae . . 221 
G. Graminese 215 



7. Cyperaceae 137' 

8. Myrtaceae 105 

9. Palmse 100 

10. Asclepiadeae 94 

11. Melastomaceae 86 

12. Compositae 83 



Ferns 791 species. 

Comparing this with the Malay Peninsula (jd. 18), we find 
the first four orders in similar places of the sequence, while 
Anonacese, ScitamineiT, and Melastomacese give way to Myr- 
tacese, Palma^, and Asclepiadeae. 

The Philippine flora has a large proportion of its species 
peculiar to it. In some families, such as the Ericaceae, Ges- 
neracese, Pandanacese, etc., almost all are so. Among species 
of limited range some interesting facts have been ascertained 
by Mr. Merrill. Of identical or closely allied species in sur- 
rounding countries, 39 have been found to extend to northern 
India, 38 to China, and 21 to Formosa, while only 9 have been 
noted in the nearer islands of Borneo, Java, and Sumatra. 
But the most decided similarity is found between the Philip- 
pines and Celebes, 76 species having been found either identical 
or represented by allied species ; and, considering how very 
imperfectly the Celebesian flora is known, the amount of simi- 
larity may be expected to be really very much greater. A sim- 



TEOPICAL PLOKAS 55 

ilar relation of the mammals, birds, and insects of the two 
island groups have been pointed out in my Island Life, and 
leads to the conclusion that the islands have, at some distant 
period, been almost or quite united. 

The Flora of Celebes 

Very little was known of the flora of this extremely inter- 
esting island till 1898, wdien Dr. S. H. Koorders published a 
large quarto volume of nearly 750 pages, giving the results of 
his own collections during four months in the north-east pen- 
insula (Minahasa) together with all that had been made known 
by the few botanists who had previously visited the islands. 

Dr. Koorders himself collected or examined 1571 species, of 
which nearly 700 were trees ; and he has given lists of 468 
species w-hich had been collected in various parts of the island 
by other botanists, making a total of 2039 species of flowering 
plants. The great peculiarity of the flora is indicated by the 
fact that nineteen of the genera of trees are not kno^\Ti in 
Java ; wdiile the affinities are, on the whole, more Asiatic than 
Australian, as is the case with the animals. The closest affin- 
ity is W'ith the Philippines, as with the birds and mammals, 
as indicated by a new genus of trees (W allacesdendron celehi- 
cwn), allied species having been since found in the adjacent 
group. Dr. Koorders also remarks that some of the plants 
have very peculiar forms, almost comparable with those I have 
pointed out m its butterflies. One of these is no doubt the 
new^ fig-tree (Ficus minaliassa) , a drawing of which forms the 
frontispiece of this volume. It is about 40 feet high, the 
fruits hanging thickly from the branches in strings 3 or 4 feet 
long, giving it a very remarkable appearance. His general 
result is, that the flora is very rich in peculiar species, but 
rather poor in peculiar genera. 

As this work is wholly in Dutch, I cannot give further 
details, but having counted tlie species in each natural order 
I will add a list of the ten largest orders for comparison with 
others here given : — 



56 



THE WOELD OF LIFE 



\ 



1. Urticaeese 158 

2. Legviminosse 105 

3. Rubiacese 103 

4. Euphorbiaceae 100 

5. Orchideae 81 



6. Palmaeeae 78 

7. Gramineae 71 

8. Compositse 63 

9. :\Iyrtaeea». 58 

10. Meliaceae 58 



I will add a few words on a point of special interest to 
myself. Having fonnd that tlie birds and mammals of the 
eastern half of the Archipelago Avere almost wholly different 
from those in the western half, and that the change occurred 
abrnptly on passing from Bali to Lombok, and from Borneo 
to Celebes (as explained in chapter xiv. of my Malay Archi- 
pelago), the late Professor Huxley proposed that the straits 
between them should be called '' Wallace's Line," as it forms 
the boundary between the Oriental and Australian regions. 
But later, as stated in my Island Life, I came to the conclu- 
sion that Celebes was really an outlier of the Asiatic continent 
but separated at a much earlier date, and that therefore Wal- 
lace's Line must be dra^vn east of Celebes and the Philippines. 

The Flora of New Guinea 

Early botanical explorers in Kew Guinea were disappointed 
by finding the flora to be rather poor and monotonous. This 
was the case with Prof. O. Beccari, who collected on the north- 
w^est coast; and Mr. H. O. Forbes, of the Liverpool Museum, 
informs me that he formed the same opinion so long as he had 
collected on the lowlands near the coast, but that on reaching 
a height of near 1000 feet a much richer and quite novel flora 
was found. Prof. Beccari, who is at this time studying the 
palms from various recent Dutch, British, and German collec- 
tions, now thinks that the number of species in Xew Guinea 
is probably as gTeat, in equal areas, as in Borneo or the Malay 
Peninsula, but that the species are not so distinctly marked 
as in those countries. Thev are what he terms second-ffrade 
species as compared with the first-grade species of the latter. 
But he forms this opinion chiefly from the palms, of which 
he makes a special study. 



TKOPICAL riOKAS 57. 

Dr. Lauterbach, who is engaged in describing the new plant- 
collections recently obtained, is evidently much impressed by 
them. He states that down to 1905 there were known from 
German Xew Guinea 2048 species of flowering plants, while 
about 1000 additional species had been found in other parts 
of the island. But the last Dutch expedition, from the por- 
tions of the collections he has examined, will probably add 
another 1000 species. Again he says that from collections 
recently made by Schlechter in German Xew Guinea, and 
through letters from him, an ^' immense increase in the number 
of species is in prospect.'^ A few^ more years of such energetic 
collecting will disclose more of the treasures of this the largest 
of the great tropical islands, while its grand central chain of 
mountains may be expected to produce a large amount of nov- 
elty and beauty. Dr. Lauterbach's conclusion, in a letter to 
Prof. Beccari, is as follows : " I believe, indeed, that one would 
not estimate it too highly if one reckoned the sum total of the 
Papuan Phanerogams at a round number of 10,000." Con- 
sidering that ^ew Guinea has more than double the area of 
the Philippines (which Mr. Merrill also estimates may con- 
tain 10,000 species) ; that it is nine times the area of the 
Malay Peninsula, which has already more than 5000 species 
described; that it has the enormous length of 1500 miles, all 
between 0° and 11° of S. latitude; that it has an extremely 
varied outline ; that it possesses abundant diversity of hill and 
valley, and a central range of mountains which have now been 
proved to rise far above the line of perpetual snow ; and finally, 
that it is almost everywhere clad with the most luxuriant for- 
ests, and enjoys that moist and equable equatorial climate 
which is proved to be most favourable to vegetable as well as 
to insect life, it seems to me probable that it may ultimately 
prove to be among the richest areas on the earth's surface. In 
bird-life it seems likely to surpass any other equal area, and it 
may do so in plants also, but In the luxuriance of insect-life 
I am inclined to think that it will not equal the richest por- 
tions of equatorial America. 



68 THE WORLD OF LIFE 

The only other tropical flora in the eastern hemisphere in- 
cluded in my table is that of Queensland, which is mostly 
within the tropics, but a large part of the interior consists of 
elevated plains with a rather arid climate where little of the 
luxuriance of tropical vegetation is to be met with. Probably 
not more than one-fourth of the area is clothed with a typical 
tropical vegetation, but this has as yet been very partially 
explored botanically. The number of species compares best 
with that of the Indian peninsula, with wdiich it agrees nearest 
in area ; and both these countries, though very rich in certain 
districts, cannot be considered to present examples of the full 
luxuriance of tropical vegetation. 

Floras of Tropical Africa and America 

The floras of the remainder of the tropics are, for various 
reasons, of less interest for the purposes of this work than 
those of the eastern hemisphere, and a very brief reference to 
them wdll be here given. Although Africa has a tropical area 
nearly equalling those of Asia and America combined, it has a 
flora of less extent and of less botanical interest than that 
of either of them. Its area of luxuriant tropical forest is 
comparatively of small extent, and much of it is yet unex- 
plored, so that the number of species in the latest enumeration 
is perhaps more than might have been expected. The islands 
belonging to Africa — ■ Madagascar, Mauritius, Bourbon, and 
the Seychelles — are, however, of extreme interest, on account 
of the remarkable character, as well as the extreme speciality, 
both of their plants and animals. As, however, these pecul- 
iarities have been rather fully discussed in chapter xix. of my 
Island Life, it is not necessary to repeat them here. I may 
state, however, that in Mauritius there are about 40 peculiar 
genera, nearly all of shrubs or trees, while no less than 5 
peculiar genera of palms are found in the Seychelle Islands. 
The following table of tlie sequence of orders in Madagascar 
may be of interest for comparison with those of other large 
floras. 



TROPICAL FLOEAS 59 

Madagascar (5000 species) 



1. Leguminosae 346 

2. Compositae 281 

3. Euphorbiaceae 228 

4. Orchideae 170 

Ferns 



5. Cyperaceae 160 

6. Rubiaceaj 147 

7. Acantluiceae 131 

8. Giamineae 130 

318 species. 



The above table was made when the whole flora consisted 
of 3740 known species. As it is now increased to nearly 5000, 
the figures given will have to be increased by one-third on the 
average. But as this increase may be very unequal, they have 
been left as sriven. 






Flora of Tropical America 

We have seen reason to believe that the temj^erate flora of 
^orth America is somewhat poorer than that of Europe and 
northern Asia, though the south temperate zone as represented 
by Chili is exceptionally rich. But there can be little doubt 
that its whole tropical flora is extremely rich ; and it may not 
improbably be found to contain nearly as many species of 
plants as all the rest of the tropical world. This may per- 
haps be indicated by the fact that it has fourteen or fifteen 
natural orders quite peculiar to it, wdiile the remainder of the 
globe has about the same number ; but, taking account of 
three other orders that are almost exclusively American, Mr. 
Hemsley is of opinion that the balance is on the side of 
America. 

America has the great advantage of possessing the largest 
continuous or almost continuous extent of tropical forest on 
the globe. The vast Amazonian plain forms its central mass 
of about two millions of square miles of almost continuous 
forest. From this there are northward extensions over the 
Guianas and parts of Venezuela, along the north-east branch 
of the Andes to Trinidad, and thence through Panama and 
Honduras to the lowlands of eastern and western Mexico. 
Southward it sends out numerous branches along the great 
river valleys into central and western Brazil, and thence along 



60 THE WORLD OF LIFE 

the eastern slopes of the Andes to beyond tlie southern tropic; 
while all along the Atlantic coast there is a belt of equal lux- 
uriance, spreading out again in the extreme south of Brazil 
and Paraguay to about 30° of south latitude. We could thus 
travel continuously for about five thousand miles from Mexico 
to northern Argentina in an almost unbroken tropical forest, 
or about the same distance down the Amazon valley to Par- 
anahyba in northern Brazil, and then, after a break of a few 
hundred miles, along the east coast forests for about two thou- 
sand miles more. This probably equals, if it does not surpass, 
the tropical forest area of the rest of the globe. 

We must also take into account the fact that, as a rule, 
tropical forests differ from those of the temperate zone in the 
s^^ecies not being gregarious, but so intermingled that adjacent 
trees are generally of distinct species, while individuals of the 
same species are more or less widely scattered. When, from 
some commanding elevation, we can look over a great extent 
of such a forest, we can usually see, at considerable intervals, 
a few, perhaps a dozen or more, small patches of identical 
colour, each indicating a single tree of some particular species 
which is then in flow^er. A few^ days later we see a different 
colour, also thinly scattered; but in the region of the most 
luxuriant tropical forests we never see miles of country thickly 
dotted with one colour, as would often be the case if our Euro- 
pean oaks or beeches, birches or pines, produced bright-col- 
oured flowers. This fact would alone indicate that the tropical 
forests are wonderfully productive in species of trees and woody 
climbers, and hardly less so in shrubs of moderate size, which 
either live under the shade of the loftier trees or line the banks 
of every river, stream, or brooklet, or other opening to which 
the sun can penetrate. In those latter positions there is also 
no lack of herbaceous plants, so that the whole flora is exceed- 
ingly rich, and the species composing it rapidly change in 
response to the slightest change of conditions. 

The difficulty of collecting and preserving plants in these 
forest-clad areas is so great, and the number of resident bot- 



TEOPICAL FLORAS 61 

anists who alone could adequately cope with the work is com- 
paratively so small, that it is not surprising to find thai the 
great forest region of tropical America is still very imperfectly 
known. Only tw^o considerable areas have been systematically 
collected and studied — in ^orth America the entire tropical 
portion from South Mexico to Panama commonly known as 
'" Central America " ; and in South America the vast areas of 
Brazil, itself comprising more than half of tropical South 
America. The comparatively easy access to this latter country, 
the attraction of its gold and diamond mines, its extensive 
trade with England and with other civilised countries, have 
all led to its being explored by a long series of botanists and 
travellers, the result of whose labours have been incorporated 
in a moniimental work, the Flora Brasiliensis of Martins, re- 
cently completed after more than half a century of continuous 
labour. 

The number of species described in this work is 22,800, an 
enormous figure considering that its area is less than half that 
of tropical Africa, and that probably two-thirds of its surface 
has never been thoroughly examined by a botanist. The Cen- 
tral American flora, as described by Mr. Hemsley,^ in less 
than one-third of the area of Brazil has about 12,000 species, 
and this is no doubt a much nearer approach to its actual num- 
bers than in the case of Brazil. 

As regards the additions that may yet be made to that flora, 
and especially to the great forest region of adjacent countries, 
I will quote the opinion of a very competent authority, the late 
Dr. Bichard Spruce, who assiduously studied the flora of the 
Amazon valley and the Andes for fourteen years, and himself 
collected about 8000 species of flowering plants, a large pro- 
portion of which were forest-trees. In a letter to Mr. Bentham 
from Ambato (Ecuador), dated 22nd June 1858, he writes: " I 
have lately been calculating the number of species that yet 
remain to be discovered in the great Amazonian forest from 

1 See Biologia Centrali Americana, by Messrs. Godman and Salveri; 
Botany, 4 vols., 1888. 



62 THE WORLD OF LIFE 

the cataracts of the Orinoco to the mountaius of Matto Grosso. 
Taking the fact that by moving away a degree of latitude or 
longitude I found about half the plants different as a basis, 
and considering what very narrow strips have up to this day 
been actually explored, and that often very inadequately, by 
Humboldt, Martins, myself, and others, there should still 
remain some 50,000 or even 80,000 species undiscovered. To 
any one but me and yourself, this estimation will appear most 
extravagant, for even Martins (if I recollect rightly) emits 
an opinion that the forests of the Amazon contain but few 
species. But allowing even a greater repetition of species than 
I have ever encountered, there cannot remain less than at least 
half the above number of species undiscovered." ^ 

Spruce was one of the most careful and thoughtful of writers, 
and would never have made such a statement without full con- 
sideration and after weighing all the probabilities. In the 
same letter he describes how, when leaving the Uaupes River 
after nine months of assiduous collecting there in a very lim- 
ited area, a sunny day after continuous rains brought out' 
numerous flowers, so that as he floated down the stream he 
saw numbers of species quite new to him, till the sight became 
so painful that he closed his eyes to avoid seeing the floral 
treasures he was obliged to leave ungathered ! At Tarapoto 
he observed that some flowers opened after sunset and dropped 
off at daAvn, so that they would be overlooked by most collectors, 
while of many the flowering season was very limited, sometimes 
to a single day. Join to this the scarcity of individuals of 
many species scattered through a trackless forest, and it is evi- 
dent that the true floral riches of these countries will not be 
fully appreciated till numerous resident botanists are spread 
over the entire area. 

From the facts of distribution given by Mr. Hemsley we 
learn that about one-twelfth of the species of Central America 

1 See Spruce's Xotes of a Botanist on the Amazon and Andes, vol. ii. p. 
208. 



TEOPICAL FLORAS 63 

are found also in South America, and that about TOO are found 
in the eastern portion from Venezuela to Brazil, so that prob- 
ably not more than 500 reach the latter country. The com- 
bined floras of Brazil and Central America, even as now 
imperfectly loiown, will therefore reach about 34,300 species. 
N^ow, considering how very rich the eastern slopes of the Andes 
are known to be, and that the average width of the forest zone 
between Brazil and the Andes is from 400 to 500 miles, while 
the plateaux and western slopes also have a rich and distinct 
flora and fauna, I think it will be admitted, that whatever the 
combined floras of Brazil and Central America may amount 
to, that number will be nearly or quite doubled when the entire 
floras of Venezuela, the Guianas, Colombia, Ecuador, and Peru 
are thoroughly explored. As, roughly speaking, Brazil con- 
tains about half the great tropical forests of South America, 
and allowing that its portion is the best kno^vn, we may fairly 
add one-third of Spruce's lower estimate (25,000) to its 
present numbers, Avhich will bring the whole to very nearly 
40,000 sjDecies. By doubling this, we shall reach 80,000 as 
the probable number of species existing in tropical South 
America. 

As this number is considerably more than half the latest 
estimate of the number of flowering plants yet known in the 
whole world (136,000 species),^ more than half of which 
number will be absorbed by the comparatively well-known tem- 
perate floras, it will be apparent that we have at present a very 
inadequate idea of the riches of the tropical regions in vege- 
table life. This result will be further enforced by additional 
facts to be adduced later. 

I will here give a table of the few known statistics for trop- 
ical America, which, though very fragmentary, will serve to 
show the basis on which the preceding estimate of probable 
numbers rests. 

1 This number has been given me by Mr. W. B. Hemsley, Keeper of the 
Kew Herbarium, as being that of Dr. Tlionner in 1008. 



64 



THE WORLD Or LIFE 



Floras of Tropical America 



Country. 


Area, 
Sq. Miles. 


De 

scribed 
Species. 


Remarks. 


Mexico (8.) and Cen- 1 

tral America J 

Brazil 


910,000 

3,200,000 

79,000 

4,200 

1,750 

2,400 


12,000 

22,800 

3,000 

2,722 

1,967 

445 


Hemsley, 1888 
Martins 


Nicaragua to Panama .... 
Jamaica 


Hemsley 

L. N. Brittan, 1909 


Trinidad 


J. H. Hart, 1908 


CralaDasros 


(1902) 







Note. — The number of Trinidad plants is from a Herbarium 
List by Mr. J. H. Hart, F.L.S., Superintendent of the Botanical 
Gardens, published in 1908. He states, however, that "a large 
amount of material has not been arranged under natural orders " 
and that "the later added specimens have not been arranged for 
several years past." But he adds, " As it now stands, there is 
a good representation of the Trinidad flora." 

Mr. W. B. Broadway of Tobago, who has lived several years in 
Trinidad and has studied its flora, informs me that from his own 
observation he believes that many hundreds of additional species 
remain to be collected; and this is what we should expect, as the 
island is a continental one ; while Jamaica, though larger, is almost 
oceanic in character, and is therefore almost certain to have a less 
complete representation of the tropical American flora than the 
former island. 

The great work on the flora of Mexico and Central America 
deals, unfortunately for my present purpose, with an area in 
which temperate and tropical, arid and humid conditions are 
intermingled to a greater extent even than in the case of 
British India already referred to. Mexico itself comprises 
about four-fifths of the whole area, and nearly half its surface 
is north of the tropic and is largely composed of lofty plateaux 
and mountains. It thus supports a vegetation of a generally 
warm-temperate but rather arid type; and these same condi- 
tions with a similar flora, also prevail over the great plateau 
of southern Mexico. This type of vegetation extends even 



TEOPICAL FLORAS 65 

farther south into the uphuuls of (liiateinala, so that we only 
get a wholly tropical flora in the small southern section of the 
area from Kicaragua to Panama. 

The following table of the twelve largest orders in the whole 
flora Avill be of interest to compare with that of British India; 

Mexico and Central America (11,688 species) 



1. Compositse 1518 

2. Leguminosae 944 

3. Orchidese 938 

4. Gramineae 520 

5. Cactaceae 500 

6. Rubiaceae 385 



7. Eiiphorbiacese 368 

8. Labiata? 250 

9. Solanaceae 230 

10. Cyperaceae 218 

1 1. Piperaeese 214 

12. Malvaceae 182 



Ferns 545 

The most remarkable feature in this table is the great pre- 
ponderance of Compositse characteristic of all the temperate 
and alpine floras of America, and the presence of Cactaceae, 
Solanaceae, Piperaeese, and Malvaceae among the 12 predomi- 
nant orders, the first of the four being confined to America. 

It may be noted that of the 12 most abundant orders 8 are 
the same in these two very widely separated parts of the earth. 
But even this table greatly exaggerates the actual difference 
between the two very distinct floras. There are 175 natural 
orders in British India, and of these only 20 are absent from 
the Mexican region. Of these 20 orders 18 have less than 10 
species (5 of them having only 1 species), so that, judging 
from the great types of plants, the difference is wonderfully 
small. We can therefore understand Sir Joseph Hooker's 
view, that there are only two primary geographical divisions of 
the vegetable kingdom, a tropical and a temperate region. 

It must be remembered, however, that even when the series 
of orders in two remote areas are nearlv identical, there mav 
be a very marked difference between their floras. Orders that 
are very abundant in one area may be very scarce in the other ; 
and even when several orders are almost equally abundant in 
both, the tribes and genera may be so distinct in form and 
structure as to give a very marked character to the flora in 



66 THE WORLD OF LIFE 

which they abound. Thus the Urticacese include not only 
nettles, hops, and allied plants, but mulberries, figs, and bread- 
fruit trees. Even Avith so much identity in the natural orders, 
there is often a striking dissimilarity in the plants of distinct 
or remote areas, owing to the fact that the genera are very 
largely different, and that these often have a very distinct 
facies in leaf and flower. Thus, though the Myrtacese are 
found in hot or warm countries all over the world, the Euca- 
lypti, so abundant in Australia, give to its vegetation a highly 
peculiar character. So the Onagracese are found in all the 
temperate regions, yet the Fuchsias of South-temperate 
America are strikinoly different from the Willow-herbs of 

CD «- 

Europe or the CEnotheras of ^^Torth America ; and there are 
thousands of equally characteristic genera in all parts of the 
world. 

In Mr. Hemsley's elaborate table of the General Distribution 
of Vascular Plants, he gives, in Central America, the number 
of species of each order in Nicaragua, Costa Rica, and Panama 
respectively, these three states constituting the tropical section 
of the whole area, and the same for six subdivisions of the rest 
of the area. But the numbers added together will give more 
than the actual number of species in the combined flora, be- 
cause an unlvnown portion of the species will be found in two 
or three of these divisions. But he gives the total numbers 
for these three states and also for the remainder of the nine 
areas. He also gives the numbers which are '^ endemic " in 
these two groups of areas separately and in the whole flora ; I 
have therefore been able to ascertain the proportion which the 
endemic bear to the total in Mexico and Guatemala, which I 
find to be as 3 to 4 verv^ nearly, so that by deducting one-fourth 
of the sum of the species in these areas I obtain the number 
existing in the combined area. But as it is known that in the 
tropics species have a less range than in the temperate zone, 
I deduct one-fifth in the case of the three tropical areas, which 
will, I believe, approach very nearly to the actual number of 
species in the combined floras as given in the following table. 



TEOPICAL FLOEAS 67 



Nicaragua, Costa Kica, and Panama (3000 species) 



1. Orchidcai 280 

2. Conipositu? 107 

o. LegLiiniiiQsaj 17(3 

4. Riibiaeete 14(5 

5. Uraminetp iH) 

6. Eiiphoibiacese 72 



7. Gesneraceaj GO 

8. Cyperawa? 08 

0. Alelastomacea^ 07 

10. Urticacoai 58 

11. Aioideie 5-t 

12. Palraai 50 



Ferns 252 

This table brings out clearly the extra-tropical character of 
Mexico as compared with these tro|)ical sections of Central 
America. Xo less than five orders of the former twelve have to 
be omitted (Cactacea?, Labiates, Solanacese, Piperaceas, and Mal- 
vaceae), which are replaced by the more exclusively tropical Ges- 
neracea?, Melastomacese, Urticacese, xVroideae, and Palmte. 
Here, in two adjacent areas differing about 12° in mean lati- 
tude, there is a more pronounced difference in the prevalent 
orders of plants than exists between two great regions on oppo- 
site sides of the globe. Another characteristic tropical feature 
is seen in the large number of ferns, which are nearly one- 
half those of the whole number found in Mexico and Central 
America, which has an area nine times as great. 

Of the other tropical American floras little need be said. 
Jamaica and Trinidad are the onlv West Indian islands of 
the larger group for which I have been able to get recent 
figures. Mr. L. ]^. Brittan, of the ]^ew York Botanical Gar- 
dens, who has collected in the former island, estimates the 
species at 2722, which, for a sub-oceanic island, is a large 
amount. Trinidad, which is almost a part of the continent, 
should be much richer, and its existing collections, not quite 
reaching 2000, are certainly much below its actual number 
of species. The Galapagos, now probably fairly well known, 
but possessing only 445 species, show us how scanty may be 
the flora of a group of islands of considerable size and situated 
on the equator, when the conditions are not favourable for 
plant-immigration or for the gTowth of plants at or near the 
sea-level, as has been pointed out in my Island Life. 



Q8 THE WOKLD OF LIFE 

The Flora of Lagoa Santa 

There is, however, one small area in the Campos of Brazil 
in about 20° S. lat. and 2700 feet above the sea-level, which 
has been thoroughly explored botanically bv a Danish botanist, 
Professor Eug. Warming, who lived there for three years with 
his fellow-countrvman Dr. Lnnd, who first studied the fossil 
vertebrates in the caves of the district. This was in 1SG3-66; 
and after studying his collections for twenty-five years with the 
assistance of many other botanists he published in 1892 a 
quarto volume giving a most careful account of the vegetation 
in all its aspects, with numerous very characteristic illustra- 
tions, both of individual plants and of scenery, forming one 
of the most interesting botanical works I have met with. Un- 
fortunately it is printed in Danish, but a good abstract (about 
thirty pages) in French renders it accessible to a much larger 
body of readers. 

This flora is strictly limited to an area of sixty-six square 
miles, so that every part of it could be easily explored on foot, 
and again and again visited as different species came into 
flower or ripened their fruit. The surface is undulating and 
in parts hilly, with a lake, a river, some low rocky hills, 
marshes, and numerous deeply eroded ravines and valleys, often 
with perpendicular rocky sides, where there is perpetual mois- 
ture and a rich forest-vegetation. But everywhere else is for 
half the year arid and sun-baked, covered with scattered decid- 
uous trees and shrubs, and during the rains producing a fairly 
rich herbaceous vegetation. It is, in fact, a good example 
of the campos that occupy such a large portion of the interior 
of Brazil, though perhaps above the average in productiveness. 

An open country such as this is, of course, much easier to 
examine thoroughly than a continuous forest, which, though 
actually richer, calls for a much longer period of exploration 
before all its riches can be discovered. But though the coun- 
try is so open, with trees and shrubs spread over it in a park- 
like manner, Mr. Warming tells us that trees of the same spe- 



TROPICAL FLORAS 



69 



cies are so widely scattered that it is sometimes difficult to 
find two of the same kind. Another interesting fact is, that 
the number of species of all kinds — trees, shrubs, and herbs — 




ei 



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is twice as great in the patches of forest as in the open campos, 
while the two are so distinct that he believes them to have 
hardly a species in common. 



TO THE WORLD OF LIFE 

Through the kindness of Professor "Warming I am able to 
reproduce here a few of his characteristic drawings and photo- 
graphs, with descriptions furnished by himself. These offer 
a striking contrast to the photographs of typical Malayan vege- 
tation at pp. 48 and 50. 

As shewn in the view on p. 69 (Fig. 3) the vegetation cov- 
ering the hills is w^hat is termed ^^ cam2:)os limpos," consisting 




Fig. 4. — The Campo Cerrado; Lapa Vermelha Rocks to the Right. 

of grasses and herbs with small shrubs, but with few trees 
scattered in the grass-land. These trees are low, the stems 
and branches tortnons or twisted. In the valleys where the 
soil is richer in hnmus and always moist, there is thick forest. 



TEOPICAL FLOKAS 



71 



The soil in all the campos is red clay. In the distance is seen 
the smoke of fires on the campos. In the foreground is a 
'' campo cerrado," i.e. a campo with many trees, but never so 
close that the sun does not shine on the dense carpet of high 
grasses and herbs under the trees ; which latter belong mostly 
to the Leguminosge, Ternstromiacese, Vochysiacese, Anonacese, 
Bignoniacese, etc. 

Fig. 4 is a view taken in the " Campo cerrado," showing the 
stunted form of the trees which characterise it. In the back- 
ground are calcareous cliffs, in which are the fossil-producing 
caves. At the foot of the cliffs the trees are closer and higher ; 
and on the top is a more open and dry forest, each kind of 
forest having its peculiar species of trees. 

Fig. 5 (facing p. 72) is a view taken close to the rocks. 
The upper branches of Mimosas and other trees are shown, 
which grow at the foot of the cliffs, one of them being a tree 
of the custard-apple family, whose branches are fruit-laden. 
Numerous tall cactuses (Cereus ccerulescens) are seen growing 
up from the rock itself, and several stinging and thorny plants. 
Other genera growing on the rocks are Opuntia, Pereskia, 
Peperomia, Epidendrum, Tradescantia, Gloxinia, Amaryllis, 
Bomarea, Griffinia, and many others, so that we have here a 
curious mixture of forest trees and climbers with moisture- 
loving plants and those characteristic of arid conditions, all 
growing close together if not actually intermingled. 

Before describing a few of the special peculiarities of the 
campo vegetation of Lagoa Santa, I will here give some numer- 
ical data of interest to botanical readers. The sequence of the 
orders in this very interesting flora is as follows : — 

Lagoa Santa (2490 species) 



1. Compositae 26G 

2. Leguminosae 235 

3. Gramineae 158 

4. Orchidaceae 120 

5. Euphorbiaceae 100 

6. Myrtacese 100 



7. Rubiaceae 94 

8. Cyperaceae 77 

0. Malpighiaceap 04 

10. INIelastomaceae 62 

1 1. Labiatae 49 

12. AsclepiadeiB 48 



Ferns and allies 106 species. 



72 THE WORLD OF LIFE 

The chief feature which distinguishes this flora from that of 
Nicaragua and Costa Rica is the presence in some abundance 
of the highly characteristic South ximerican order Malpighia- 
cese, the high position of Myrtacese, with Labiates and Ascle- 
piads in place of Aroids and Palms. Of the rather numerous 
Orchids about 70 are terrestrial, 50 epiphytes. There are over 
40 genera, of which Spiranthes has 16 species, Habenaria 12, 
while 22 have only 1 species each. The very large American 
genus Oncidium has only 5 species, while the grand genus 
Cattleya, so abundant in many parts of Brazil, seems to be 
entirely absent. 

Adaptations to Brought 

The plant figured on the next page, like many others of the 
campos, has its roots swollen and woody, forming a store of 
water and food to enable it to withstand the effects of drought 
and of the campo-fires. The old stems show where they have 
been burnt off, and the figures of many other plants with woody 
roots or tubers, figured by Mr. Warming, show similar effects 
of burning. 

Still more remarkable is the tree figured on p. 74 (Fig. 7), 
which is adapted to the same conditions in a quite different 
way, as are many other quite unrelated species.-^ The group 
of plants is really an underground tree, and not merely dwarf 
shrubs as they at first appear to be. What look like surface- 
roots are really the branches of a tree the trunk of which, and 
often a large part of the limbs and branches, are buried in 
the earth. The stems shown are the root-like branches, which 
are 4—5 inches diameter, w^hile the growing shoots are from 
2 to 3 feet high. The whole plan (or tree) is from 30 to 40 
feet diameter. As the branches approach the centre they de- 

1 The following species have a similar mode of gro\vth : Anacardium 
Jiumile, Hortia Brasiliensis (Riitacese), Cochlospermum insigne (Cistaceae), 
Simaha Warniingiana (Simariibaeese) , Erythroxylon campestre (Erythroxy- 
laceae), Plumiera Warmingii ( Apocynaceae ) , Palicourea rigida (Cincho- 
naceae ) , etc. 




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TROPICAL FLOEAS 



73 




Fig. 6. — Casselia Chamcedrifolia, nat. size (Verbenacefie) . 

scend into the earth and form a central trunk. A French 
botanist, M. Emm. Liais, says of this species: " If we dig we 



74 



THE WORLD OF LIFE 



find liow all these small shrubs, apparently distinct, are joined 
together underground and form the extremities of the branches 
of a large subterranean tree which at length unite to form a 
single trunk. M. Eenault of Barbacena told me that he had 




Fig. 7. — Andira Laurifolia (Papilionacese). 

dug about 20 feet deep to obtain one of these trunks." The 
large subterranean trees with a trunk hidden in the soil form 
one of the most singular features of the flora of these campos 
of Central Brazil. 

The above facts are from Mr. Warming's book, supplemented 
by some details in a letter. They are certainly very remark- 
able ; and it is difficult to understand how this mode of growth 
has been acquired, or how the seeds get so deep into the 
ground as to form a subterranean trunk. But perhaps the 
cracks in the dry season explain this. 

A large part of these campos is burnt every year at the end 
of the dry season, but as the vegetation is scanty the fires pass 



TKOPICAL FLORAS T5 

quickly onwards and do not appear to kill or injure the trees 
or even the small herbaceous plants. In fact, numbers of 
these plants as soon as the rains come produce foliage earlier 
than Avhere there has been no fire, and often produce flowers 
when unburnt trees or shrubs of the same species remain 
flowerless. Mr. Warming and otlier botanists believe that the 
practice of firing the campos was a native one long before the 
European occupation, and that many of the plants have become 
adapted to this annual burning so as to benefit by it. 

It is interesting to note here the opinions of two eminent 
botanists, only thirty years ago, as to the comparative riches 
of certain tropical and temperate countries. In his great work 
on The Vegetation of the Globe, Griesbach thus refers to the 
Brazilian flora : ^^ The results of the explorations of Martins, 
Burchell, and Gardiner, cannot be compared with those fur- 
nished by the Cape. The number of endemic species may per- 
haps reach 10,000, but the area is twenty times greater than 
that of Cape Colony, and we may conclude that, as regards its 
botanical riches, the Brazilian flora is very far from rivalling 
that of the extremity of South Africa." Gardiner, however, 
after spending three years in collecting over a large portion 
of the interior of Brazil, though chiefly in the campos and 
mountain ranges, concludes his account of his travels with these 
w^ords : " The countrv is beautiful, and richer than anv other 
in the world in plants." This general statement may not be 
strictly true, but it seems clear that the facts already adduced 
are sufficient to show that, as regards the comparison of tem- 
perate with tropical floras, there can be no doubt as to the 
superiority of the latter. This point will, I think, l)e made 
still clearer in the following discussion of some almost unno- 
ticed facts. In the case of Brazil and Cape Colony, however, 
it is clear that Griesbach was creatlv in error. Tlie wliole 
area of extra-tropical South Africa has probably been as well 
explored botanically as Brazil, the richest portions of which 
have been only as it were sampled. Yet wo find less than 
14,000 species in the former against 22,S00 in the latter. It 



76 THE WOELD OF LIFE 

will be now shown that when smaller and better known areas 
are compared the superiority of the tropics is more clearly 
apparent. 

The Floras of Small Areas and their Teachings 

The conclusions already reached by the examination of the 
chief floras of the world, whether in areas of continental extent, 
or in those more approaching to the average of our counties, 
that, other things being equal or approximately so, the tropics 
are far more prolific in species, will receive further confirma- 
tion, and I think demonstration, from data I have collected 
as to the botanical richness of much smaller areas, which having 
been more thoroughly explored afford more reliable evidence. 
They also afford very suggestive facts as to the best mode of 
future exploration which may enable us to arrive at a fair 
approximation as to the total world-population of flowering 
plants. 

For the convenience of readers I give here two tables I 
have prepared of the floras of small areas in tropical and tem- 
perate zones, each arranged in the order of their area in square 
miles for convenience of reference and comparison. 

I will now briefly discuss the various interesting questions 
raised by a consideration of these tables. 

It is, I believe, still a very common opinion among botanists 
that the wonderfully diversified flora of the Cape Region of 
South Africa is the richest in the whole world in so limited 
an area. This is partly owing to the fact that such a large 
proportion are beautiful garden plants, which for sixty years, 
from 1775 to 1835, j^oured in a continued stream into Europe 
and seemed almost inexhaustible. The wonderful group of 
heaths, of which there are about 350 species, all beautiful and 
many among the most exquisite of flowers ; the almost equally 
numerous pelargoniums, the brilliant ixias, gladioli and allies, 
the gorgeous proteas, the w^onderful silver-tree, the splendid 
lilies and curious orchises, the endless variety of leguminous 
shrubs, and the composites including the everlasting flowers. 



TEOPICAL FLORAS 



77 



Tropical Floras — Small Areas 



Place. 



1 
2 
3 
4 
5 
6 



Malacca 

Singapore 

Penang 

Lagoa Santa, Brazil 

Mount Pangerango, Java 
Kambangan Island, Java 



Area. 


Species. 


660 


2000 


206 


1740 


107 


1813 


66 


2488 


n 


1750 


n 


2400 



Authoritj'. 



Gamble. 

Ridley. 

Curtis. 

Warming. 

Koorders. 

Koorders. 



Temperate Floras — Smalt. Areas 



1 
2 

3 
4 
5 
6 
7 
8 
9 
10 



Place. 



Mount Nikko, Japan .... 

Cape Peninsula 

Schaffhausen 

Washington, D.C 

Hertford ( near ) 

Paramatta River, Sydney 

Capri, Italy 

Edmondsham, Dorset 

Cadney, Lines 

Tliames Ditton 



Area. 


Species. 


360 


800 


180 


1750 


114 


1020 


108 


922 


80 


810 


20 


620 


4 


719 


3 


640 


3 


720 


1 


400 



Authority, 



Havati. 

Bolus. 

A. de Candolle. 

Ward. 

A. de Candolle. 

H. Deane. 

Beguinot. 

Rev. E. F. Linton. 

Rev. Woodruffe-Peacock. 

H. C. Watson. 



together with hundreds of other delicate and beautiful little 
greenhouse plants, — formed an assemblage which no other 
country could approach. Rich as it is, however, there is now 
reason to believe that West Australia — Swan River Colony 
in its original restricted sense — is quite as productive in spe- 
cies, while evidence is slowly accumulating that many parts 
of the tropics are really still more productive. 

The first to be noticed of these rich tropical areas of small 
extent is the island of Penang in the Straits of Malacca, which, 
though only 106 square miles in area, contains 1813 species. 
Sir Joseph D. Hooker, in his Sketch of the Flora of British 
India (1906), terms this " an astonishing number of species," 
and remarks on the large proportion which are arboreous, and 
of the altitude of the island being only 2750 feet. TTere, there- 



78 THE WOKLD OF LIFE 

fore, in an area considerably less than that of the Cape Pen- 
insula, the species are actually more numerous, and this was 
evidently a new and astonishing fact to one of the greatest of 
our living botanists. 

But the somewhat larger island of Singapore shows us that 
this amount of productiveness is quite normal; for though it is 
206 square miles in extent, it is almost flat, the greatest eleva- 
tion being only a few hundred feet. A large part of the sur- 
face is occupied by the town and suburbs, while the original 
forest that covered it has been almost all destroved. Yet Mr. 
Ridley finds it to have recently contained 1740 species, and 
when the town was founded and the forest untouched, it almost 
certainly had 2000 or even more. 

We have seen also that Lagoa Santa in South Brazil, 
2700 feet above sea-level, with a much smaller area than 
Penang, and a much less favourable climate, has one-third 
more species, mainly collected by one enthusiastic botanist 
during three years' work in this limited district. Here are no 
mountains, the whole country being an undulating plateau, 
while for six months there is so little rain that the trees 
almost all lose their leaves. The aridity causes the trees to 
be mostly stunted and unshapely; the leaves are clothed on 
one or both surfaces with felt or dense hairs; and the stems 
of herbaceous plants are often swollen into thick tubers 
either underground or just above it. There is thus a mani- 
fest struggle for existence ajrainst the summer drought with 
intense sun-heat, and it would hardly be imagined that under 
such conditions the number of species would equal or exceed 
that of some of the most luxuriant parts of the tropics. 

I will now pass on to a consideration of the two last 
items in the table of small tropical floras, which are more 
instructive and even amazing than any I have met with in 
the course of this inquiry. "\^^ien I was in Java about fifty 
years ago I ascended the celebrated mountains Gede and 
Pangerango, the former an active, and the latter, much the 
higher, an extinct volcano. The two, however, form one 



TROPICAL FLORAS T9 

mountain with two summits. During the ascent I was much 
impressed by the extreme hixuriance of the forest-growth, and 
especially of the undergrowth of ferns and herbaceous plants. 
I was told by the gardener in charge of the nursery of 
cinchonas and other plants, that 300 species of ferns had been 
found on this mountain, and I think 500 orchids. I was 
therefore anxious to learn if any figures for the plants of 
the whole mountain could be obtained, and was advised by 
the Director of Kew Gardens to apply to Dr. S. Koorders of 
the Reijks Museum, Leiden. In reply to my inquiries, Dr. 
Koorders wrote me as follows : — 

"The botanical mountain-reserve on the Gede (Pangerango) is 
indeed very interesting and very rich, but I know other parts of 
Java with a much larger number of phanerogams, e. g., the small 
island of Xoesa Kambangan near Tjilatjap. On that island I 
collected on an area of about 3 square kilometres (= 1% square 
mile) 600 of arborescent species of phanerogams, and about 1800 
species of not-arborescent species. This island is about — 50 m. 
altitude (=164 feet).'' 

" On Mount Pangerango, between 5350 feet and the top, 10,000 
feet, the number of forest-trees is about 350 species on the same 
area, and about 1400 species of not-arborescent phanerogams." 

On reading the above, I thought at first that Dr. Koorders 
must have made a mistake, and have meant to write 30 in- 
stead of 3 square kilometres. So I wrote to him again ask- 
ing for some further information, and pointing out that 
Kambangan Island was many times larger than the area he 
had given. To this he replied that he " only explored a small 
part methodically," and that the number of species he gave 
me '^ were found in that part only." ^ It thus became clear 

1 It may seem to some readers, as it did at first to myself, that it is im- 
possible to have over two thousand species of flowering plants growing 
naturally on about a square mile. But a little consideration will show 
that it is by no means so extraordinary as it seems. Let us suppose that 
the average distance apart of trees in an equatorial forest is ten yards, 
which I think is much more than the average; then in a square mile there 
will be 176 X 170 = 30,976 trees. But in Kambangan Island there are 600 



80 THE WORLD OF LIFE 

that no mistake had been made. I was further satisfied of 
this bj referring to a small volume by M. Jean Massart, en- 
titled Un Botaniste en Malaisie. He there describes the 
^' mountain reserA'e " on Pangerango as being 300 hectares of 
virgin forest, extending from the limits of cultivation to near 
the summit. As '' 300 hectares " is the same area as '' 3 
square kilometres/' there can be no doubt as to the figures 
given. M. Massart also states that Dr. Koorders was head 
of the " forest-fiora " department of the Buitenzorg Botanical 
Gardens, and that he had established eighteen other reserves 
in various regions of Java. Each of these reserves is under 
a native superintendent, who allows no tree to be cut down 
without orders, and watches for the flowering and fruiting of 
every species of tree. One specimen at least of all the species 
is numbered, and paths made and kept in order, so that they 
can be easily visited, and the flowers or fruit gathered for the 
herbarium. Dr. Koorders has now obtained specimens of 
about 1200 trees indigenous to Java, while 3500 specimens 
have been numbered in the reserves. This number is without 
counting either shrubs or climbers. 

I give here a reproduction of a charming little photo- 
graph taken in West Java more than fifty years ago by my 
friend, the late Walter Woodbury, and I believe in the south- 
ern country not very far from the island which Dr. Koorders 
found so rich (Fig. 8). The intermingling of dwarf palms 
and ferns, with the varied foliage of shrubs and herbaceous 
plants, and the abundance of lianas hanging everywhere from 
the trees overhead, give an impression of tropical luxuriance 
beyond even that of the Malayan photographs pp. 48 and 49. 

The system of small forest reserves in tropical or other im- 

species of trees in IJ square mile, so that each species would be represented 
on the average by 60 individuals. But, as some are comparatively common, 
others rare, there would in some cases be only 3 or 4 specimens, while many, 
having from 50 to 100, would be really abundant, but, if fairly scattered 
over the whole area, even these might require searching for to find two or 
three specimens; which accords with the facts as testified by all botanical 
travellers. 







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TEOPICAL FLORAS 81 

perfectly known countries seems to ine to offer so many ad- 
vantages that the adoption of it in Java by the Dutch botanists 
must, I think, be looked upon as an important discovery. It 
has the great advantage of being at once economical and ef- 
fective; it brings about the maximum of scientific result with 
the minimum of cost, of time and of labour. It has proved 
that the careful and systematic study of very small areas is 
calculated to extend our knowledge of the vast world of plant- 
life more than any other that has hitherto been adopted. The 
plan is to have, in any extensive country or island, a suit- 
able number of what may be termed " botanical reserves " 
(but which wdll also serve as zoological reserv^es, especially for 
bird and insect life) ; these to be of small size, say one square 
mile each, to be kept absolutely in a state of nature, except 
the provision of numerous paths giving access to at least one 
specimen of every species of tree the reserve contains. Ex- 
perience in Java seems to show that one man, or two if 
necessary, can keep the paths open, watch for the flowering 
and fruiting of trees, gather and send specimens to the head 
of the department, and also, I presume, serve as guide to any 
botanical visitors to the reserve. But when the trees had been 
all found, numbered, and named, the same superintendent 
or keeper would have time and opportunity for the collec- 
tion of specimens of all the shrubs, climbers, epiphytes, and 
herbs that grew in the reserve, identifying the place of all 
the rarer species by direction and distance from the nearest 
named tree, the epiphytes, orchids, ferns, mosses, etc., being 
identified by the tree they grew upon being numbered, and 
made accessible by a path. Of course this area of 3 square 
kilometres, or about a square mile, may not be in all 
cases sufficient, but it seems likely to be the most suitable for 
luxuriant tropical forests. In more open country, as at 
Campo Santo, a space of from 10 to 50 square miles might 
be advisable, because the trees on such an area might be as 
easilv found as in a mile of unbroken forest, and w^ould not 
be much more numerous. In any new tropical country of 



82 THE WOKLD OF LIFE 

Avhicli ^ve obtain possession, or where there are still large areas 
of virgin forest, it would be advisable to reserve one square 
mile in each square degree, say one in every 5000 square 
miles. 

There are many incidental advantages in this thorough de- 
termination of the plants growing on a definite if small area 
over that which has usually been adopted of, as it were, skim- 
ming the cream of the flora of enormous areas, such as most 
of our botanical collectors have been obliged to adopt. The 
first advantage is that the census of species in each of the 
reserved areas can be easily made exhaustive, and therefore 
comparable with other similar reserves. Then, when a few 
well-chosen " reserves " are similarly treated, the change of 
species in each degree of latitude and longitude can also be 
determined with considerable accuracv. In like manner the 
change of species for each 1000 or 500 feet of elevation can 
also be found. Again, the proportion of forest trees to the 
whole of the flowering plants in each locality will enable the 
whole flora of a large district to be determined as to numbers 
by ascertaining the number of species of trees only in a few 
small areas. 

As an illustration of this mode of computation Dr. Koorders 
has found that on the Pangerango mountain the trees form 
one-fifth of the whole flora, while on Kambangan Island they 
form one-fourth. If there are, as Dr. Koorders tells me, 
about 1200 species of trees actually found in Java, and if, 
on account of the eastern part of the island having much less 
lowland forest, we take one-fifth as the more probable pro- 
portion for the whole, then the flora of Java may be estimated 
at a minimum of 6000 species; and if the number of the 
trees is found to be greater, then at a proportionately higher 
number. Hence it is very important that in each local flora 
the number of its trees, shrubs, and herbs should be separately 
given. It appears that a forest reserve of 17 square miles 
has been established on the Bay of Manilla ; but, as it is as 
yet very imperfectly explored, it would be more useful to 



TROPICAL FLORAS 83 

thoroughly explore two or three well-chosen areas of one square 
luilo each. 

It is really deplorable that in so many of our tropical de- 
pendencies no attempt has been made to preserve for posterity 
any adequate portions of the native vegetation, especially of 
the virgin forests. As an example, the island of Singapore 
was wholly covered with grand virgin forest at the begin- 
ning of last century. When I was there in 1851 the greater 
part of it was still forest, but timber-cutting and clearing 
for gambir and other plantations has gone on without restric- 
tion till there is now hardly any true virgin forest left ; and 
quite recently the finest portion left has been allowed to be 
destroyed by a contractor in order to get gi-anite for harbour 
w^orks, which might almost as easily have been obtained else- 
where. The grand forest trees were actually burnt to make 
way for the granite diggers ! 

Surely, before it is too late, our Minister for the Colonies 
should be urged without delay to give stringent orders that 
in all the protected Malay States, in British Guiana, Trinidad, 
Jamaica, Ceylon, Burma, etc., a suitable provision shall be 
made of forest or mountain '' reserves," not for the purpose 
of forestry and timber-cutting only, but in order to preserve 
adequate and even abundant examples of those most glorious 
and entrancing features of our earth, its native forests, woods, 
mountain slopes, and alpine pastures in every country under 
our control. It is not only our duty to posterity that such 
reserves should be made for the purpose of enjoyment and 
study by future generations, but it is absolutely necessary in 
order to prevent further deterioration of the climate and de- 
struction of the fertility of the soil, which has already taken 
place in Ceylon and some parts of India to a most deplorable 
extent. For this end not only must timber-producing forests 
of an ample size be secured, but on all mountain slopes con- 
tinuous belts of at least 400 or 500 yards wade should be 
reserved wherever forests still exist, or where they have been 
already lost be reproduced as soon as possible, so as to form 



84 THE WOKLD OF LIFE 

retainers of moisture by the surface vegetation, checks to 
evaporation by the shade of the trees, guards against torrential 
rains, mud slides, snow slides where such are prevalent, and 
protection against winds. On level or nearly level ground, 
where such varied uses would not be required, similar belts 
at greater distances apart should be saved for local uses and 
amelioration of climate, besides " botanical reserves " of ade- 
quate extent to give a representation of each type of vege- 
tation in the country. 

I would also strongly urge that, in all countries where there 
are still vast areas of tropical forests, as in British Guiana, 
Burma, etc., all future sales or concessions of land for any 
purpose should be limited to belts of moderate breadth, say 
half a mile or less, to be followed by a belt of forest of the 
same width; and further, that at every mile or half-mile, 
and especially where streams cross the belts, transverse patches 
of forest, from one to two furlongs wide, shall be reserved, 
to remain public ]3roperty and to be utilised in the public 
interest. Thus only can the salubrity and general amenity 
of such countries be handed on to our successors. Of course 
the general position of these belts and clearings should be 
determined by local conditions; but there should be no ex- 
ception to the rule that all rivers and streams except the very 
smallest should be reserved as public property and absolutely 
secured against pollution; while all natural features of es- 
pecial interest or beauty should also be maintained for public 
use and enjoyment. 

The great Eoraima mountain in British Guiana, for ex- 
ample, with at least half a mile of forest around its base, 
should, so far as w^e are possessors of it, be absolutely se- 
cured; and generally, every important mountain summit, with 
ample means of access, should also be reserved, so that they 
may not be monopolised or defaced by the greed of specula- 
tive purchasers. It should always be kept in mind that the 
reckless clearing of large forest-areas, especially in the tropics, 
produces devastation which can never be repaired. It leads 



TROPICAL FLORAS 85 

to the denudation of the rich surface soil bj torrential rains ; 
this soil has been produced by countless ages of forest growth, 
and it will require an equal lapse of time to reproduce it. 

Returning now to the more direct teachings of small areas 
when methodically studied, I may add that Dr. Koorders has 
informed me that some years since he made a visit to 
Minahassa, in X. Celebes, and in four months, between the 
sea-level and 6500 feet, he collected or observed about 2000 
species of flowering plants, of wdiich about 700 were forest 
trees. As these last are Dr. Koorders' special study it is 
to be presumed he paid great attention to them, yet he could 
hardly have obtained such a complete knowledge of them in 
a few months as in the ^' reserves " of Java, where, in suc- 
cessive years, not a single species could have escaped dis- 
covery. This would imply that the forest flora of Xorth 
Celebes is even richer than that of Java, and it is almost 
certainly more peculiar. And if the larger islands of the 
Moluccas — Gilolo, Batchian, and Ceram — are equally rich 
(and they have all the appearance of being so), then every 
estimate yet made of the species-population of the whole 
Archipelago must be very far below the actual numbers. 

There must be hundreds of young botanists in Europe and 
America who w^ould be glad to go to collect, say for three 
years, in any of these islands if their expenses were paid. 
There would be work for fifty of them, and if they were prop- 
erly distributed over the islands from Sumatra to Xew Guinea 
in places decided upon by a committee of botanists who knew 
the country, with instructions to limit their work to a small 
area which they could examine thoroughly, to make forest 
trees their main object, but obtain all other flowering plants 
they met with, a more thorough and useful botanical explora- 
tion Avould be the result than the labours of all other col- 
lectors in the same area have accomplished, or are likely to 
accomplish, during the next century. And if each of these 
collectors had a moderate salary for another three years in 
order to describe and publi^^h the results of their combined 



8Q THE WORLD OF LIFE 

work on a uniform plan, and in a cheap form, the total ex- 
pense for all the nations of Europe combined would be a 
mere trifle. Here is a great opportunity for some of our 
millionaires to carry out this important scientific exploration 
before these glorious forests are recklessly diminished or 
destroyed — a work which would be sure to lead to the dis- 
covery of great numbers of plants of utility or beauty, and 
would besides form a basis of knowledge from which it woukl 
be possible to approach the various great governments urging 
the establishment, as a permanent possession for humanity, of 
an adequate number of such botanical, or rather biological, 
^' reserves '' as I have here suggested in every part of the 
world. 

Before leaving the very interesting problems suggested by 
the floras of '' small areas," I will point out that in the tropics, 
in warm temperate and in cool temperate zones alike, the evi- 
dence goes to show that mountain floras are not so rich in 
species as those of the plains. I have already shown that it 
is the case in our own islands, in Switzerland and in South 
Euroj^e. The table of extra-European small areas (p. 40) 
shows that the gTeat Japanese mountain, Fujiyama, with a 
larger area and an altitude of over 12,000 feet, has a smaller 
number of species than Mt. Kikko, with a smaller area and 
an altitude of only 8000 feet, both mountains being cultivated 
to the same height (800 feet), and both being equally well 
explored. And now, coming to the tropics, we find in Java 
two areas of the same extent and fullv explored bv the same 
botanist, one on a grand mountain slope from 4500 to 0500 
feet, and celebrated for its rich flora, the other at the sea- 
level, and the latter is decidedly the richest. Yet we find 
Gardiner, in his Travels in Brazil, taking the very opposite 
of this for granted. He says, at the end of his Avork : '' Xo 
good reason has yet been suggested to account for the greater 
number of species which exist on a given space on a mountain 
than on a plain." The answer seems to be that there is no 



TROPICAL FLORiVS 87 

such general fact to be explained. There may often, no doubt, 
be more plants on some mountains than on the adjacent plains, 
especially on open plains where social plants abound. On 
mountains the botanist can often collect more species in the 
same time, because diversities of soil and station are more 
crowded together, but the accurate determination of the species 
on areas from one square mile up to some hundreds of miles 
shows that the fact is almost uniformly the other way. 

It is also of special interest to note that the well-known 
fact in our own country, that a parish of 2 or 3 square miles 
in area often contains more than half the flora of the whole 
county many hundred times as great (as in the cases of Cad- 
ney, Edmondsham, and Thames Ditton, given in the table), 
appears to be even exaggerated in the more luxuriant tropical 
forests, where a single square mile often contains as many 
species as 100 miles in similar forests elsewhere. 

It is, however, interesting to note that when we compare 
very small areas, measured by feet or yards instead of by 
square miles, it is the temperate floras which seem to have 
a decided advantage. Darwin records that on a piece of turf 
3 feet X 4 feet long exposed to uniform conditions, (prob- 
ably on the chalk downs of Kent or the Isle of Wight) he 
found twentj" species of plants belonging to eighteen genera 
(Origin of Species, 6th ed. p. 88). Sir Joseph Hooker in 
the Himalayas, 11,480 feet above the sea, in the upper Lachen 
valley, found a much richer vegetation. He says : ^^ Herba- 
ceous plants are much more numerous here than in any other 
part of Sikhim; and sitting at my tent door I could, without 
rising from the ground, gather forty-three plants, of which 
all but two belonged to English genera." And in a note ho 
adds : " In England thirty is on the average the equivalent 
number of plants which in favourable localities I have 
gathered in an equal area." ^ 

In my limited reading I have found no other reference to 
this form of species-abundance, nor do any of my botanical 
I Himalayan Journals (olieap ed.), p. 335, 



88 THE WOELD OE LIFE 

friends appear to have recorded such; hut it Avould be inter- 
esting to know if any parts of Switzerland or the Pyrenees 
were as rich as the Himalayas. I should expect not, as the 
latter has a great advantage in area, and also I presume in 
climate. The snow protection in winter would be similar, 
but I presume the summer would be somewhat longer and the 
temperature more equable, while the more nearly vertical sun 
and much greater rainfall would probably lead to a more 
luxuriant development of species than in higher latitudes, or 
less elevated stations. Darwin points out that the produc- 
tion of short velvety flower-decked turf depends entirely on 
its being regularly cropped down by ruminants, preventing 
the more delicate plants from being smothered by the coarser. 
Now, this group of animals is one of the latest developments 
of the world of life; and we thus learn that these delight- 
ful expenses of flower-enamelled turf are actually produced by 
the sheep or goats, the deer or antelopes whose presence gives 
them a further charm, and which were themselves developed 
just at the period when man appeared upon the earth, gifted 
with faculties which enables him alone to fully appreciate 
their beauty, and to utilise many of them as aids to his own 
civilisation. 



CHAP TEE y 

THE DISTEIBUTIOiq^ OF ANIMALS 

The sketch now given of the broader features of the distribu- 
tion of plants over the various parts of the earth's surface 
will apply, with little modification, to the various classes of ani- 
mal life, which, although having the power of locomotion, are yet 
by the necessity of acquiring food and preserving themselves 
from enemies, almost as strictly limited to definite areas as 
are plants themselves. 

It will only be necessary to give a few facts to illustrate 
this, for which purpose insects and birds afford the most in- 
structive materials. We will begin with the Lepidoptera, or 
Butterflies and Moths, in our own country and in a typical 
county. The following data have been kindly furnished by 
Mr. William Cole, F.L.S., Hon. Sec. of the Essex Eield 
Club. 

Distribution of Lepidoptera 

Sq^Mfles. ^^''''''• 

Great Britain 87,500 2070 

Essex 1,530 1655 

In order to compare the numbers in a smaller area, I have 
only materials for the Macrolepidoptera or Butterflies and 
larger Moths. 

Sq^MHes. ^^'''''■ 

Great Britain 87,500 822 

Essex 1,530 620 

Epping Forest 10 428 

It is interesting to note here the curious correspondence 
with the number of the flowering plants, which in the mean 
of twelve counties was almost tlio same as the area in miles; 

89 



90 THE WORLD OF LIFE 

and here we find the total number of the Lepidoptera in 
Essex, which is not far from an average county, very nearly 
the same as its area. The number of species of these insects 
is also suggestive, in being about one-half greater than the 
number of flowering plants (1010) on which they almost all 
feed in their larval state. We know that many different 
species feed on some of our commonest plants — as the oak, 
poplar, elm, nettle, etc. — while some larv^^e feed on several 
distinct plants indiscr,iminately. But probably the larger 
number feed on one species of plant only, and thus almost all 
our plants, except the very rarest, afford food for at lea^t one 
lepidopterous larva. 

Again, just as we found that a selected area of 10 square 
miles in Surrey had nearly two-thirds of the plants in the 
whole county, so here we find that a selected area of 10 square 
miles in Essex has nearly two-thirds of the Macrolepidoptera 
found in the county. Here, too, we see the result of the de- 
pendence of the insects on the plants, the great variety of 
the latter in Epping Forest (150 species) rendering possible 
a corresponding variety of the former. 

Coleoptera (Beetles) 

The enormous order of the beetles (Coleoptera) not being 
exclusively feeders on living plants, but both in their larval 
and perfect state often feeding on animal food or on vege- 
table debris, are probably more uniform in their numbers in 
different areas if not absolutely barren or very highly culti- 
vated. 

Area. Species. 

Great Britain 87,500 3260 

Essex 1,530 1655 

As it requires perseverance in collecting for many years 
in order to obtain all the beetles in even a very limited 
district, I think it probable that the above figures do not so 
closely represent the actual number of species inhabiting the 
county as in those given for the plants, or even the moths. 



THE DISTRIBUTION OF AOTMALS 91 

To show the vast numbers and variety of the insect tribes, 
I give here the approximate numbers of actually described 
insects, kindly furnished me by Mr. C. O. Waterhouse of the 
Entomological Department of the Natural History Museum. 

Insects of the World. Number of Described 

Species. 

Coleoptera (Beetles) 120,000 

Lepidoptera ( Moths and Butterflies ) 00,000 

Hymenoptera (Bees, Wasps, Ants, etc.) 45,000 

Diptera (Flies, Gnats, Midges, etc.) 28,000 

Rhynchota (Bugs, Cicadas, etc.) 18,000 

Orthoptera (Locusts, Crickets, etc.) 8,000 

Neuroptera ( Dragon-flies, May-flies, etc. ) 5,000 

Several smaller Orders 5,000 

Land Area, 48,000,000 square miles 240,000 

I 

If we consider that large areas of the most productive 
tropical regions are still almost unexplored by the ento- 
mologist, and that even in the best-known parts the less 
attractive groups are very little known, it is almost certain 
that the actual number of species of insects now in existence 
is double that above given, while it may be three or four 
times as many. 

To show how difficult it is to ascertain how many species 
of insects are now known to exist, I give another recent esti- 
mate by Mr. A. E. Shipley, F. R. S., in his Presidential 
Address to the Zoological Section of the British Association 
in 1909. This was based upon a careful estimate by Dr. 
Giinther, in 1881, when Keeper of Zoology in the British 
^luseum. His estimate then was 220,150 species of insects. 
In the twenty-seven succeeding years, the 7.ooJogical Record 
gives the number of new species described in all parts of the 
world. During the whole of this time the numbers described 
have increased vear bv vear, and Air. Shiplev has therefore 
taken the number for the vear 1897 as an averaa'c of the 
wliole (8364 n.s.), and multijdying this by 27 ('allowing the 
odd 364 for synonyms) we have an addition of 216,000, which 



92 THE WOKLD OF LIFE 

added to 220,000 gives a total now known of JfS6,000, an 
immense increase on the estimate of Mr. Waterhouse. Of 
course a far more correct way would be to add the number 
described as new, each year of the twenty-seven; but as this 
would involve the counting of all the descriptions in thousands 
of pages of close print, we cannot be surprised that such a 
labour was not undertaken. 

It is hardly possible for any one who has not collected 
some special group of insects in countries where they abound, 
to realise what the numbers given above really mean. In 
the Malay Islands alone, I myself collected over a thousand 
distinct species of one of the most beautiful families of beetles 
— the Longicorns — of which about 900 were previously quite 
unknown. Of another immense family — the Curculionidge, 
or Weevils — I obtained also about 1000 species, of which the 
same proportion were new. Wliile the former group are re- 
markable for grace of form, variety of marking, and often for 
exquisite colouration, the latter are equally interesting for 
their endless modifications of shape, more sober but beauti- 
fully marked bodies, strangely bossed surfaces, and, occa- 
sionally, the most brilliant metallic colours. 

The interest of making such collections, in which the variety 
was so great as to seem absolutely endless, may be imagined 
by any lover of nature. But the interest in their study has 
been intensified by the firm conviction — the growth of half 
a century of thought upon the subject — that every detail of 
these wonderful modifications of structure, form, and coloura- 
tion, have been due to general laws in operation for count- 
less ages, and that every minutest character, as they occurred 
through successive variations and became fixed in each species, 
had a definite purpose; that is, were of use to the creatures 
which exliibited them. This, however, will be shown later 
on, when we have to deal with the more important factors 
of evolution — variation and heredity. 



THE DISTRIBUTION OF ANIMALS 93 

The Species of Birds 

We will now pass on to the most familiar, the most beauti- 
ful, and the most wonderful of all living things — the birds. 
These form one of the culminating lines of development of 
the great world of life ; they are the most specialised of all 
the higher animals ; and so far as perfection of organised 
structure is concerned may be considered to hold a higher 
place than the mammals themselves. Were they not so familiar 
to us, we should consider it to be impossible that warm-blooded, 
active creatures, with a bony skeleton, could have their fore- 
limbs (or arms) so modified as to be used exclusively for 
flight, and yet, with no organ of prehension but the mouth 
prolonged into a beak, sometimes aided by a foot, be completely 
adapted to obtain every kind of vegetable or animal food, to 
protect themselves from enemies, and to construct the most 
perfect abodes for their helpless young to be found among the 
higher animals. 

Some zoologists consider that in the power of flight birds 
are surpassed by insects, but I cannot think this to be the 
case. If we take into consideration the weight they have to 
carry, the height they often attain above the earth, their per- 
fect command over the direction and speed of their motion, 
and the exquisite and highly complex organ by which flight 
is effected, birds must take the higher place. The insect's 
flight is simpler and more automatic; that of the bird more 
elaborate in every part, more completely under the control 
of the creature's will. It is also, I believe, more varied in 
exact adaptation to the mode of life of each of the species. 

As regards their variety of structure, the numbers of the 
species, and their mode of distribution over the earth's sur- 
face as compared with the other forms of life already con- 
sidered, a few examples will be sufficient to prove their general 
correspondence with other animals. It must be remembered, 
however, that in birds the numbers inhabiting the several 
countries are less precise and less comparable than in any other 



94 THE WORLD OF LIFE 

group. This is due to several causes. In all extra-tropical 
lands a large proportion of the species are migratory, and the 
facts observed are very similar over the whole of the north 
temperate zone. Some go to more northern lands in summer 
to breed, returning south in autumn ; others leave us in autumn 
to winter in the south, returning to lis in the spring; others, 
again, are birds of passage only, staying with us a few days 
or weeks on their way north or south. All these are con- 
sidered to be truly natives, in our case to be ^' British birds." 
But others only visit ns occasionally, some at very long inter- 
vals, while others, again, are mere " stragglers," who have 
lost their way or been driven to us by storms, and have only 
perhaps been recorded (seen or killed) once or twice. There 
is therefore a vast range for personal opinion as to what species 
should or should not be included as " British " or " European " 
or '^ Canadian " birds. If we add to this uncertainty the 
extreme variety of opinion as to the limits of ^' species," " sub- 
species," and " varieties," or ^' local races " of birds which 
now exist, we see how hopeless it is to expect uniformity in 
numerical estimates of the birds of different countries or re- 
gions. As an example of this difference of treatment, we may 
take two of the most recent estimates of the bird-population 
of the world. Dr. Glinther, in 1881, estimated the species 
of birds then known at 11,000, and Mr. Shipley added to this 
an average of 105 new species per annum — estimated from 
the y.oological Record — for the twenty-seven years elapsed 
since that date, bringing the total up to 13,835. But in the 
late Dr. Bowdler Sharpens Hand List of the Genera and 
Species of Birds, just completed, the number is stated as being 
18,937. This enormous divergence, as I am informed by an- 
other great authority on Ornithology, Dr. P. L. Sclater, is 
mainly, if not wholly, due to the fact, that Dr. Sharpe '^ in- 
cludes as species all the numerous slight local forms which 
are called ' sub-species ' by the new school of Ornithologists, 
many of which, in my opinion, do not present sufficient dif- 
ferences to require separation at all." 



THE DISTRTBUTIOIsr OF AXIMALS 



95 



Keeping tlicse difficulties iu mind, the following estimates, 
for which I am largely indebted to my friend, Mr. Henry 
Dresser (author of a great work on the Birds of Europe), will 



be found interesting. 



Species of Birds 



Square Miles. 



Europe 

Great Britain 
Dorset 



3,850,000 

87,000 

988 



Number of Species. 



770 
410 
2101 



Mansel-Pleydell's Birds of Dorset. 

The numbers for Dorset are obtained by omitting all the 
" stragglers " and very rare visitors, including all that are 
regular immigrants or birds of passage, as well as those which, 
though irregular, are tolerably frequent visitors. Here, again, 
we see that a county area has rather more than half the 
British species, as was the case wdth flowering plants and 
some of the most extensive orders of insects. 

The difficulty of obtaining really comparable figures for the 
countries and regions shown on page 96 is at present insuper- 
able, but the approximations given are of considerable interest. 

The same table exhibits several points of interest, espe- 
cially as regards the correspondence of the proportionate 
numbers of such different organisms as birds and plants. As 
regards the Palsearctic and N^earctic regions (temperate 
Europe and Asia on the one hand, temperate North Am.erica 
on the other), we see that the birds of the former are about 
one and a half times those of the latter, the areas being nearly 
as two to one. The plants are probably not far from the 
same proportion; for if we take those of Europe with North 
Africa at 10,000, and add thereto those of the Flora Orientalis 
of Boissier (12,000), and the China flora of Hemsley (9000), 
and allowing that the species common to any two of these may 



96 



THE WOELD OF LIFE 



Table of the Species of Birds 



Region or Country. 



Palaearctic Region 

Nearctic Region 

Ethiopian Region 

Oriental Region 

British India 

Borneo 

Philippines 

Neotropical Region 

Central America and 
South Mexico 

Brazil 

Australian Region 

Australia 

New Guinea 



Area, 
Sq. Miles. 



17,000,000 
8,000,000 
7,555,000 
3,350,000 

1,560,000 
297,000 
115,500 

7,590,000 

940,000 
3,288,000 
3,500,000 
3,009,000 

310,000 



Number 

of 
Species. 



1250 

760 

2490 

2300 

1617 
500 
700 

4100 

1300 
1568 

883 
950 



Dresser. 

Ridgway. 

Reichenow, 

Estimate. 

Dresser 

Ernst Hartert (1910) 



Biol. Am. Cent. (1905), 
Von Thering (1907). 

E. Hartert (1908). 
Ernst Hartert. 



The numbers for the Oriental Region have been estimated on the method of Mr. 
Shipley above referred to; and the same has been done for the Neotropical and 
Australian Regions. 

The numbers for Central America and Mexico have been reduced from those of 
the Biologia Am. Cent., because that work includes all temperate Mexico with a 
large number of Nearctic species. 

be about equal to additional species of the whole of N'orth 
Asia and Japan, we get a total of 31,000 species, which is 
far beyond the highest estimate of the Xearctic flora with all 
the sub-species included. 

The birds of the Ethiopian and Oriental Regions appear 
to be approximately equal in numbers. The flowering plants 
are even less known. Those of tropical Africa with Madagas- 
car, Mauritius, etc., must reach about 22,000 species; while 
temperate South Africa has 13,000. Allowing the species 
common to both to equal those yet undescribed from tropical 
Africa, we get a total of 35,000 species for the Ethiopian 
flora. 

That of the Oriental Rei^ion is much more difficult to ar- 
rive at. Taking 15,000 species for the tropical portion of 
the flora of British India, and addins: 7000 for Indo-China, 



THE DISTEIBUTIOX OF AXIMALS 97 

5000 for the Pliilippincs, 4000 fur Java, and the same for 
additional species of Makiysia proper (Malay Peninsula, 
Borneo, and Sumatra), and 2000 for Celebes, Ave have a total 
of 30,000, Avhich, considering that the land area of this region 
is less than half that of the Ethiopian, shows Avhat is prob- 
ably a fair approximation to the number of its flowering 
plants; though I believe it will be below rather than above 
the actual amount. 

Coming now to the [N'eotropical Region (including all South 
America and tropical Xorth America), we find our estimate of 
the birds to be almost double that of either of the other tropical 
regions. By means of a rough estimate (p. 64) I have arrived 
at 80,000 species as a not improbable number of the flower- 
ing plants for the [N^eotropical Region ; and allowing fully for 
future discoveries in the Malayan Islands and Indo-China, the 
numbers in the Oriental Region are not likely to much exceed 
half this number, thus agreeing very well with the proportion- 
ate numbers of birds in the same regions. 

The Australian Region is of less importance from the 
point of view we are now considering, because it is not ex- 
clusively temperate or tropical, but nearly equally divided be- 
tween the two. It also differs from the Oriental inasmuch 
as botanists usually claim the flora of the Moluccas and Xew 
Guinea as being essentially Malayan, and therefore belonging 
to the Oriental Region. But the flora of Xew Guinea has 
been stated by Sir Joseph Hooker to be so peculiar as al- 
most to deserve to form a Sub-region of its own ; and, till 
recently, the natural order Dipteracese, consisting of lofty 
forest-trees with very distinctive botanical characters, was 
supposed to be limited to the Oriental Region, from the 
Himalayas to Java, Celebes, and the Philippines. They have, 
however, now been found both in the ^Moluccas and Xew 
Guinea ; but as westerly winds blow^ for half the year with 
great steadiness between Celebes and Xew Guinea, it is not 
difficult to explain their presence in the latter country, as their 
solid but larire-winc-ed fruits would be easilv drifted for lonff 



98 THE WORLD OF LIFE 

distances. At all events the extreme richness of Xew Guinea 
in both birds and plants, and not improbably in insects also, 
is a matter of very great interest.^ 

Having shown by the best statistics available that the general 
phenomena of the numerical distribution of species over small 
or large areas correspond in their main features for such 
diverse groups of organisms as plants, insects, and birds, it 
is quite needless — even if it were possible — to attempt a 
similar enumeration for other groups. In reality, with the 
one exception of land-shells, the materials do not exist for 
any other organisms. Even the mammalia and reptiles have 
never been systematically collected in tropical countries, as 
hirds and insects have been collected, and what materials do 
exist are more difficult to obtain. But to give the general 
reader some notion of the extent of the whole world of life 
as now studied by biologists, I will give a tabular statement 
of the numbers supposed to be actually described, from the 
estimate made by Mr. Shipley above referred to in the case 
of insects. 

As regards these figures, I am informed by Mr. R. 
Lydekker that he considers the Mammalia to be much exag- 
gerated by writers who reckon slight local forms or varieties 
as distinct species. Thus 8 species have been made of the 
common brown bear, and 16 species of various local forms 
of mouse-deer (Tragulus). On the other hand, although the 
number of insects here given seems enonnous, Mr. D. Sharp, 
a very experienced entomologist, thinks that the number ac- 
tually existing is five times as great — that is, more than two 
million distinct species ! 

1 Eor a full explanation of the six great Zoological Regions, here enu- 
merated, the reader is referred to my Geographical Distribution of Animals, 
vol. i. chap. iv. ; or for a more popular account of them to my Island Life, 
chap. ill. 



THE DISTRIBUTION OF ANIMALS 



99 



An Estimate of the Described Species of Living Animals. 
By A. E. Shipley, F.R.S. (B. Essii. Address, 1909). 



Class. 


Estimated by 
Giinther, 18«1. 


A. E. Shiplev, 
1909. 


Remarks. 


Mammalia 


2,300 

11,000 

3,400 

11,000 

33,000 

120 

7,500 

8,070 

1,300 

220,150 

1,840 
6,070 
2,200 
400 
3,300 


9,955 

13,835 

7,180 

14,996 

62,000 

222 

13,953 

25,870 

8,725 

445,978 

15,097 
8,716 
5,008 
2,965 
6,000 


Too hi»li ! 


Birds 


(R. Lydekker). 

18,939 
(R. B. Sharpe). 


Reptiles, Batrachia 

Fishes 


MoUusca 




Brvozoa, 




Crustacea 




Soiders. etc 




MvriaDods 




Insects 


Too low! 


Echinoderms 


(D.Sharp). 






Coelenterata 


. 


Snono-es 




Protozoa 










790,533 





CHAPTER VI 

THE I^UMEEICAL DISTEIBUTION OF SPECIES IN RELATION" » 

TO EVOLUTION 

The rather lengthy account I have given of the numerical 
distribution of species over both small and large areas, and 
in special relation to latitude and to climate, has a very def- 
inite object. In the first place, this distribution constitutes 
the primary and fundamental fact in the relation of species 
to the whole environment — it is, in fact, the broadest and 
most simple expression of that relation, and is thus a proper 
subject of inquiry in any general view of the world of life. 
Yet it has been strangely neglected both by botanical and 
zoological writers; and the largest and oldest collections of 
plants and animals in all countries have been so dealt with as 
to afford material for almost every form of biological research 
except this one. 

The mere enumeration of the numbers of species^ named or 
unnamed, with the localities of each specimen, in the great 
national collections of the world, would have afforded all the 
materials for such comparisons as I have here endeavoured to 
make. And if the facts were recorded in card-catalogues, 
instead of in the usual forms, there would be such a demand 
for sets of these cards applying to special groups and definite 
geographical areas, by most students or collectors, that the cost 
of such catalogues would be more than repaid. 

This numerical relation of the various groups of organisms 
in different areas or geographical divisions of the earth has 
the further advantage of being interesting and intelligible to 
the general reader, as it involves the use of hardly any tech- 
nical terms, and is therefore especially suitable for a work 

100 



DISTKIBUTION AND EVOLUTION 101 

such as the present. We will now proceed to a brief considera- 
tion of the nature and meaning of the facts set forth in the 
preceding chapters. 

The evidence, collected with extreme care for many years 
by Mr. Woodruffe-Peacock (as explained in Chapter 11.)? has 
shown us how curiously the number of species differs even 
on the smallest adjacent areas. In the same field, even when 
apparently alike everywhere in soil, in aspect, and in contour 
of surface, every plot of 16 feet square has its individuality. 
It will differ from each of the eight adjacent plots either in 
tlie number of the species it contains, or in the species them- 
selves, or in the proportions of the individuals of the various 
species. They are thus seen to be affected by very small 
differences, such as moisture, or aridity; more or less 
shade from hedges, trees, or woods; shelter from or ex^^osure 
to winds; by the vicinity of pits or quarries, woods, ponds, 
or streams. 

Now this one fact of response to the minutest change of 
conditions in the arrangement of a few^ species over almost 
identical adjacent areas is as much a case of adaptation to 
the environment through the mutual interaction of the various 
species — a struggle for existence on the very smallest scale 
' — as any of those larger and more complex cases which Dar- 
win first made known to us. 

Coming now to the fields themselves of various shapes and 
dimensions, and each limited by definite boundaries of hedge 
and ditch, bank or wall, spinneys, plantation or woods, we 
have, in our country especially, a series of unit-areas which 
may be said to form the first step in the study of botanical 
geography, and which leads us on through successively larger 
areas to regions and continents. 

In regard to these fields, the writer above quoted not only 
states their precise differences in the numbers of their species 
and the presence of certain species and absence of others which 
give to each its individuality, but lie is able in many cases 
to define the causes of that individiialitv. Besides the or- 



102 THE WORLD OF LIFE 

dinarj variations of soil, we have to take account of the effects 
of diversity of treatment as meadows, pasture, or fallow land, 
each resulting in a characteristic grouping of species easily 
recognisable over wide areas. In pasture land each kind 
of domestic animal leads to the presence or absence of certain 
species, while in the vicinity of farms or villages, the presence 
of geese, pigs, or poultry has a distinctive influence. 

What a new light these researches throw upon the develop- 
ment of the vegetation of each country during past ages ! We 
see how the indigenous vegetation of oceanic islands, in the 
total absence of mammalia, must have gradually eliminated 
some of the chance immigrants by which they were first 
stocked, and favoured others often of later date, and how, in 
the com^^etition with each other, those species which were most 
easily modified into a shrubby or arboreal type would have the 
advantage. Thus may we explain the composites, lobelias, 
violets, and plantains of the Sandwich Islands being mostly 
shrubs or even trees of considerable size, and so abundant in 
species as to form a characteristic feature of the vegetation. 
Numerous Caryophyllacese, Primulacese, and a Geranium are 
also shrubs or small trees. In the Azores a Campanula and 
a Sempervivum are shrubs. 

Again, the knowledge we have recently gained of the won- 
derfully rich mammalian fauna of temperate Xorth America 
in middle and late Tertiarv times — camels, ancestral horses 
and cattle, mastodons, and many others, which disappeared 
at the on-coming of the glacial epoch — affords us a very im- 
portant clue to the development of its special vegetation. 
Every change of animal life that so often occurred in all the 
continents — the union and separation of the sub-arctic lands 
at various epochs, the temporary separation of Xorth and South 
America in late Tertiarv times, and that of Africa from 
Europe and Asia during the Early and Middle Tertiary — 
must all have profoundly affected the special developments 
of the vegetation, as well as of the animal life, in the respec- 
tive areas. 



DISTKIEUTION AND EVOLUTION 103 

No less indicative of delicate response to variation of tem- 
perature, and therefore of close adaptation to the whole modi- 
fied environment, is the continuous increase in the number 
of species with every important change of latitude. Although 
this increase is but slight for moderate changes, and is there- 
fore liable to be masked by other favourable or adverse con- 
ditions of the environment, it yet makes itself visible in every 
continent ; and in the comparison between the north or mid- 
temperate and the tropical zones is so pronounced that in fairly 
comparable areas the tropical species are often (and probably 
on the average) double those of the temperate zones. This 
seems to be the case among the higher animals, as well as 
among all the vascular plants. 

Now all this is indicative of long and minute adjustment 
to the special inorganic as well as the organic conditions ; and 
the reason why the tropics as a whole far surpass the temper- 
ate zones in the number of their specific forms, is, not the 
greater amount of heat alone, but rather the much greater 
uniformity of climatical conditions generally, during long 
periods — perhaps during the whole range of geological time. 
Whatever changes have occurred through astronomical causes, 
such as greater excentricity of the earth's orbit, must neces- 
sarily have produced extremes of climate towards the poles, 
while the equatorial regions would remain almost unaffected, 
except by a slight and very slow rise or fall of the average 
temperature, which we know to be of little importance to vege- 
tation so long as other conditions remain tolerably uniform 
and favourable. 

It is this long-continued uniformity of favourable condi- 
tions within the tropics, or more properly within the gi'eat 
equatorial belt about 2000 miles in width, that has permitted 
and greatly favoured ever-increasing delicacy of adjustments 
of the various species to their whole environment. Thus has 
arisen that multiplicity of species intermingled in the same 
areas, none being able, as in the temperate zone, to secure such 
.a superior position as to monoj)olise large areas to the exclu- 



104 THE WOELD OF LIFE 

sion of others. Hence also it has come about that the equa- 
torial species seem to be better defined — more sharj^ly dis- 
tin2;nished from each other — than manv of those of the tem- 
perate and northern zones. They are what Dr. Beccari terms 
first-grade species, as in the case of Borneo, an island which 
forms part of what has quite recently been an equatorial con- 
tinental mass. It is interesting to note that Mr. Th. D. A. 
Cockerell has arrived at a similar conclusion from his study 
of the rich fossil flora of Florissant, Colorado, of middle or 
late Tertiary age, which shows signs of a much milder climate 
than now prevails there. Many of these plants are of genera 
now extinct or only found in more southern lands, and this ex- 
tinction is traceable to the great changes, inorganic and or- 
ganic, that have since occurred in Xorth America. He says 
(in a private letter) : 

" There was first the invasion of Old World species via Behring's 
Straits; then an incursion of S. American forms via Panama; and 
then the glacial period at the end, crowding and destroying much 
of the flora and fauna. Since the glacial period in X. America, 
there has been room for expansion, and hence the very numerous 
and closely allied species of Aster, Solidago, Senecio, and other 
jolants, as well as allied species of butterflies of the genera Arg}^nnis, 
Colias, etc. These are, most of them, not at all on the same footing 
as the tropical species. ... I think tropical species are better 
defined than those of the temperate region.'' 

It is a rather curious coincidence that if we take the mean 
area of the twelve English counties for which I have been 
able to give the figures, in geographical instead of English 
miles, the number of square miles will almost exactly equal 
the average number of their species of flowering plants. Be- 
low this area, in the mid-temperate zone, the proportion of 
species decreases, and above it increases, in both slowly at 
first and with many fluctuations, but afterAvards very rapidly, 
more especially for the larger areas, so that it requires on a 
rough average about a two hundred-fold increase of area to 
double the number of species, and about a thousand-fold to 



DISTRIBUTION A^B EVOLUTION 105 

qiuntuple it. But in all such comparisons we require a large 
number of fairly comparable cases to give a trustworthy 
average, and the materials for this do not seem to exist. Yet 
there is a striking general agreement between the numbers 
of the species in the various kingdoms, states, or colonies of 
Europe, North America, and Australia, requiring only slight 
allowances for greater area, better climate, or geological history 
to bring them into line with one another to a really remarkable 
degree. 

It appears, then, that, whether we take small areas roughly 
approximating 100 square miles, or much larger areas of from 
100,000 to 200,000 square miles, there is, over the whole world, 
an unexpected amount of agreement in the numbers of the 
flowering plants, but always showing a moderate increase from 
the colder to the w^armer parts of the earth. 

Differences of Temperate and Tropical Vegetation 

One of the chief differences between the floras of the colder 
and of the warmer parts of the earth (already referred to) is 
the greater prevalence in the former of gregarious plants. To- 
wards the northern limit of vegetation we find continuous 
forests of pines or firs, the same species often extending for 
hundreds or even thousands of miles ; while woods of birches 
extend even farther north almost up to the limits of perpetual 
snow, and in this case a single species — our common birch — • 
extends entirely across northern Europe and Asia, with allied 
species in North America. Earther south, forests of beeches, 
oaks, chestnuts, etc., are common, but seldom covering such 
large areas, being dependent on conditions of soil as well as 
of climate; while in the warmer parts of the temperate zone 
the forests are often made up of a gTeat variety of trees, 
though never so completely intermingled as in the typical areas 
of the tropics. 

Another, and perhaps more important character of the 
tropical flora, is the large number of distinct types of vegeta- 
tion which are almost or quite peculiar to ihe warmest and 



lOG THE WORLD OF LIFE 

most equable regions of the earth. This is indicated by the 
fact that about one-fourth of the natural orders of plants are 
either exclusively tropical or very nearly so, and that they 
comprise such remarkable forms as the epiphytic Orchids, the 
Bromelias, the Palms, the Pitcher-plants, Bananas, Bread- 
fruits, the Coffea and Cinchona trees, and hundreds of others 
almost unknown except to botanists. 

But the most striking feature of all is the wonderful adapta- 
tions by which every w^ell-marked place or station is occupied 
by peculiar groups of plants. The epiphytes above referred to 
• — plants which live upon trees, upon the trunks or branches, 
and especially in the forks, where they can root and establish 
themselves, not as parasites by sending their roots into the 
living tissues of the tree, but solely getting nourishment from 
the rain-water that trickles down the bark or the small quan- 
tity of decaying leaves or moss that collects there — such 
plants belong to many natural orders and are very numerous. 
Then there are the climbers, far more abundant than in any 
temperate forests, which either root in the ground and then, 
by various means, climb up to the summits of the loftiest 
trees, or which begin life by rooting in a lofty fork of a gi-eat 
tree, and then send down roots to the ground and branches 
into the air, sometimes remaining as a small bush or tree, at 
others growing so rapidly above, and clinging around the sup- 
porting tree so closely with its roots, as finally to kill its foster- 
parent, when its clinging roots unite and grow into a trunk, 
with hardly anything to show that one tree has replaced an- 
other. Then again there are numerous small trees of from 20 
to 30 feet high, which live entirely in the shade beneath the 
great forest trees. Many of these have bright-coloured or con- 
spicuous flowers growing directly out of the trunk, while there 
are none at all among the crown of leaves at the top. This ap- 
pears to be an adaptation to bring the flowers within sight of 
the butterflies, bees, and other insects which fly near the 
ground, and thus secure for them the advantages of being 
cross-fertilised. Then again there are many delicate creeping 



DISTRIBUTION AND EVOLUTION 107 

plants, especially mosses and hepaticse, that cover the whole 
surfaces of the leaves of forest trees with an exquisite tracery, 
thus obtaining the perpetual moisture they require from con- 
densation on the cool surfaces of the leaves. 

in great river valleys, where by the annual rising of the 
stream miles of alluvial plains are regularly under water for 
several months, both trees and shrubs have become adapted to 
these strange conditions, and the greater part, if not all, the 
species are quite distinct from those which grow on the un- 
flooded land. 

All these, and many other characteristic features of tropical 
vegetation, can be explained by the general constancy of the 
inorganic conditions, especially the climatic ones, which have 
undoubtedly prevailed there during whole geological periods, 
subject only to those very slow changes due to elevation, de- 
pression, and denudation of the land itself. These latter have 
been so extremely gradual as to act as a gentle stimulus to the 
various agencies continually bringing about modification of 
specific form? ; and as the climatal conditions throughout all 
these changes have continued to be highly favourable to the 
support of vegetation and of animal life, there has been a con- 
stant tendency to produce and maintain an almost exact 
equilibrium between the various species in the same area. 
None being better adapted to the environment than a great 
many others, none are able to monopolise large areas to the 
exclusion of others, as is the case in the more changeable tem- 
perate or cold regions. Whether we consider the differences 
between day and night temperatures, the variations of tem- 
perature from month to month or from year to year, or those 
extreme variations which we experience once perhaps in a gen- 
eration or in a century, such as excessively cold winters, ex- 
cessive droughts or excessive rains in summer, or long periods 
of dry and cold winds — all alike are unkno\\Ti in the equa- 
torial regions, save in a few^ limited and quite exceptional areas. 
In these more favoured portions of our earth there prevails 
such a general approach to uniformity of conditions (without 



108 THE WOELD OF LIFE 

ever reaching absolute uniformity) as seems best adapted to 
bring about the greatest productivity, together with extreme 
diversity in every department of the great world of life. 

The large amount of diversity of species we have seen to oc- 
cur in single fields long subject to almost identical conditions 
in our own country, wdth the additional fact that no plot of a 
fev7 square yards has exactly the same grouping of species and 
individuals as any of the other plots, yet each plot produces 
very nearly the same number of species, will enable us in some 
degree to appreciate the conditions of the tropics. There we 
see enormous areas subject to almost identical conditions of 
soil, climate, and rainfall, yet in every part of it exhibiting, 
amid a general -uniformity of type, a wonderful diversity in 
the shapes and structures of the forms of life, and a no less 
w^onderful balance and adaptation of each to all. How this 
result has been actually brought about in the course of evolu- 
tion through the ages we shall better understand after a brief 
exposition of the factors wdiich have been the immediate causes 
of the two great phenomena, continuous evolution, with con- 
tinuous adaptation. 



CHAPTEE VII 

HEREDITY, VARIATION, INCREASE 

In the preceding chapters I have shown how, from a con- 
sideration of the simple facts of the numerical distribution of 
species over the earth, together with the varying numbers of 
the individuals in each species and the area occupied by them, 
we are led to the conclusion that there is an ever-present strug- 
gle for existence between species and species, resulting in a 
continual readjustment to the environment. In this view 
there is no question of any change of species, but merely of 
their redistribution; we perceive that during the process very 
rare or local species may, and certainly do, die out, but we 
have obtained no clue to the method by which new species arise 
to replace them. 

This was the state of opinion among the most advanced 
writers before Darwin, and it is very clearly expressed in the 
admirable 42nd chapter of Sir Charles Lyell's Principles of 
Geology (11th edition, 18 68, but w^hich first appeared in the 
9th edition, 1853, pp. 689-701) many years before the idea 
of the transmutation of species had been seriously entertained 
by men of science. This chapter may still be read with in- 
terest even by the evolutionist of to-daj^ The reader will then 
be better able to appreciate the enormous advance made by 
Darwin by his conception of " natural selection," dependent 
on the three fundamental factors — heredity, variation, and 
enormous powers of increase — all well known to naturalists, 
but whose combined eifect had been hitherto unperceived and 
neglected. The two first of these factors we will now pro- 
ceed to discuss and elucidate. 

Perhaps the most universal fact — sometimes termed ^' law " 
— of the organic world is, that like produces like — that off- 

109 



110 THE WORLD OF LIFE 

spring are like their parents. This is so common, so well 
known to everybody, so absolutely universal in ordinary ex- 
perience, that we are only surprised when there seems to be 
any exception to it. In its widest sense as applied to species 
there are no exceptions. Not only does the acorn always pro- 
duce an oak, the cat a kitten, which grows into a cat, the sheep 
a lamb, and so throughout all nature, but each different well- 
marked race also produces its like. We recognise Chinese and 
Negroes as being men of the same species as ourselves but of 
different varieties or races, yet these varieties always produce 
their like, and no case has ever occurred of either race pro- 
ducing offspring in every respect like one of the other races, 
any more than there are cases of cart horses producing racers 
or spaniels producing greyhounds. 

Some people still think that mental qualities are not in- 
herited, because it so often happens that men of genius have 
quite undistingaiished parents, and that the children of men 
of great ability do not as a rule equal their fathers. But al- 
though such cases are frequent and attract attention because 
such apparent non-inheritance is unexpected and seems un- 
reasonable, yet when large numbers of families are carefully 
examined there is found to be the same amount of mental as 
of physical inheritance. This was proved by Sir Francis 
Galton in his work on Hereditary Genius, in which, by tracing 
the families of large numbers of public men of high position 
and some kind of exceptional talent or genius which was gen- 
erally recognised, it was found that in their ancestral line 
there was always found some amount of distinction, though 
not always of the same kind or degree; and that if they left 
descendants for two or three generations, they, too, usually 
comprised some individuals of more than average ability. 

To avoid any misconception on this point, it may be as well 
here to state brieflv the numerical law of inheritance, which 
Galton arrived at by careful experiments in the breeding of 
plants and animals, and which is now generally accepted as 
affording a very close representation of the facts of inherit- 



HEREDITY, VARIATION 111 

V 

ance under normal conditions. It is that the offspring of any 
two parents derive, on the average, one-half of their character- 
istics from tliose parents, one-fourth from their four grand- 
parents, one-eighth from their eight great-grandparents, and 
so on to remote ancestry, the total result being that one-half 
of each individual's peculiarities is derived from its parents, 
while the other half comes from its whole previous ancestry. 
Hence arises the Avell-known fact that certain peculiarities of 
body or of character are apt to reappear in families during 
several centuries. 

Xow this simple law explains almost all the facts including 
the apparent failures of inheritance — all its irregularities in in- 
dividual cases, together with its constancy and regularity when 
larse numbers are examined. It shows us whv, when families 
for several generations have been noted for beauty, for stature, 
for strength, or for talent, these characters will almost cer- 
tainly be found developed in most of their children, who from 
three or four generations of ancestors have a good chance of de- 
riving seven-eighths or fifteen-sixteenths of their entire or- 
ganisations. If, on the other hand, the beauty or talent of 
jjarents were exceptional in their respective families, then 
iheir children, having a number of commonplace or inferior 
ancestors, w^ould often be far inferior to their parents in the 
particulars in which the parents excelled, and in their case 
heredity would seem to have failed. 

Erom this consideration there is deduced another general 
law, very easy to remember and of great use in explaining ap- 
parent deviations or incongruities. This is called the '^ law" of 
recession towards mediocrity." It means that, whenever par- 
ents deviate considerably from the average of the population 
of which they form a part, their offspring will tend to return 
towards the average. Eor example, if both parents are de- 
cidedly below or above the average in height, in beauty of 
form, in any special faculty, as music, drawing, etc., their chil- 
dren will usuallv ffo back towards the averaii'e, thou2:li still re- 
taining some of the parental excess or defect. It is owing to 



112 THE WORLD OF LIFE 

tliis law that very extreme developments, whether of body or 
of mind — gigantic stature or supreme genius — are rarely 
transmitted to the next generation. But if this special su- 
periority has already persisted in the family for several gen- 
erations, and both parents belong to this same superior stock, 
then the reversion towards mediocrity is less marked, and the 
special quality will almost certainly be transmitted, sometimes 
even in still larger degree, to some members of the family. 

It is by acting on this principle that breeders of animals or 
j^lants for special purposes are able to improve the race. In 
each generation they choose the most perfect individuals, from 
their point of view^, to be the parents of the next generation, re- 
jecting or destroying all the inferior ones. It is in this way 
that our race-horses, our best milking cows, our heavy-woolled 
sheep, our quickly fattening pigs, our luscious pears and 
peaches, and hundreds of others, have been produced. Just 
in proportion as we have bred only from the best for a long 
series of generations does the transmission of these qualities 
become more certain and the '' recession tow^ards mediocrity " 
appear to be abolished. But it is not really abolished. The 
average to w^hich there is a tendency to return has itself been 
raised by careful selection of the best for many generations, 
and the inferior individuals which were once the average of 
the race are now so far removed that they can exert only a 
very slight influence on each successive generation. Owing to 
the numerical law above referred to, after five generations of 
such selective breeding it is about 100 to 1 against the inferior 
characters of the original average stock reappearing in the 
offspring, while if the operation has been carried on for ten 
generations it is about 2000 to 1 against such inferior types 
presenting themselves. It is for this reason that our great 
Colonial sheep and cattle breeders find it to their advantage 
to give even thousands of pounds for pedigree bulls or rams 
in order to improve their stocks. 

It is by what is substantially the same process, as wt shall 
see farther on, that nature works to improve her stocks in the 



HEEEDITY, VAEIATION 113 

great world of life ; and has been thus enabled nut only to keep 
all in complete adaptation to an ever-varying environment, but 
to fill up, as it were, every element, every different station, 
every crack and crevice in the earth's surface with wonderful 
and beautiful creatures which it is the privilege and delight 
of the naturalist to seek out, to study, and to mar\^el at. 

The Variation of Species, its Frequency and its Amount 

Having now shown something of the nature of heredity, its 
universality and its limitations, we pass on to a rather fuller 
discussion of the nature and amount of those limitations, com- 
monly known as the variability of species. It is this variability 
that constitutes the most important of the factors which bring 
about adaptation, and that peculiar change or modification of 
living things which we term distinct species. This change is 
often very small in amount, but it always extends to various 
parts or organs, and so pervades the whole structure as to 
modify to a perceptible extent the habits and mode of life, the 
actions and motions, so that we come to recognise each species 
as a complete entity distinct from all others. 

There is no subject of such vital importance to an adequate 
conception of evolution, w^hich is yet so frequently misappre- 
hended, as variability. Perhaps owing to the long-continued 
and inveterate belief in the immutability of species, the earlier 
naturalists came to look upon those conspicuous cases of varia- 
tion which forced themselves upon their attention as something 
altogether abnormal and of no importance in the scheme of 
nature. Some of them went so far as to reject them altogether 
from their collections as interfering with the well-marked dis- 
tinctness of species, which they considered to be a fundamental 
and certain fact of nature. Hence, perhaps, it was that Dar- 
win himself, finding so little reference to variation among wild 
animals or plants in the works of the writers of his time, had 
no adequate conception of its universality or of its large general 
amount whenever extensive series of individuals were com- 
pared. He therefore always guarded himself against assuming 



114 THE WORLD OF LIFE 

its presence whenever required bj using such exj^ressions in 
regard to the power of natural selection as, '' If thej vary, for 
unless thej do so, natural selection can effect nothing." 

This was the more strange because wherever we look around 
us we find, in our own species, in our own race, in our own 
special section of that race, an amount of variation so large 
and so universal as to fully satisfy all the needs of the evolu- 
tionist for bringing about w^hatever changes in form, structure, 
habits or faculties that may be desired. By simply observing 
the people we daily meet in the street, in the railway carriage, 
at all public assemblages, among rich and poor, among lowly- 
born or high-born alike, variability stares us in the face. We 
see, for instance, not rarely, but almost daily and everywhere, 
short and tall men and w^omen. We do not require to measure 
them or to be specially good judges of height to be able to 
observe this — the difference is not one of fractions of an 
inch only, but of wdiole inches, and even of several inches. 
We cannot go about much without constantly seeing short 
men who are about 5 feet 2 inches high, and tall men who are 
6 feet 2 inches — a difference of a w^hole foot, while in almost 
every town of say 10,000 inhabitants, still greater differences 
are to be found. 

But this special variation, so large and so frequent that it 
cannot be overlooked, is only one out of many which we may 
observe daily if we look for them. Some men have long legs 
and short bodies, others the reverse ; some are long-armed, some 
are big-handed, some big-footed, and these differences are found 
in men differing little or nothing in height. Again we have 
big-headed and small-headed men, long-headed and round- 
headed, big-jawed, big-eared, big-eyed men, and the reverse; 
we see dark and light complexions, smooth or hairy faces ; 
black, or brown, or red, or flaxen-haired men; slender or stout 
men, broad or narrow-chested, clumsy or graceful, energetic 
and active, or lazy and slow. Characters, too, vary just as 
much. Men are taciturn or talkative, cool or passionate, intel- 
ligent or stupid, poetical or prosy, witty or obtuse. And all 



HEREDITY, \^xUaAT10X 115 

these characteristics, whether physical or mental, are combined 
together iii an infinite variety of ways, as if each of them 
varied independently with no constant or even usual associa- 
tion with any of the others; whence arises that wonderful 
diversity of appearance, attitudes, expression, ability, intellect, 
emotion, and what we term as a wdiole character, which adds 
so much to the possibilities and enjoyments of social life, and 
gives us in their higher developments such mountain peaks of 
human nature as were manifested in Socrates and Plato, Homer 
and Virgil, Alexander and Phidias, Buddha and Confucius in 
the older world ; in Shakespeare and ^N^ewton, Michael Angelo, 
Faradav, and Darwin in more recent times. 

And with all this endless variation wherever we look for it, 
we are told again and again in frequent reiteration, that varia- 
tion is minute, is even infinitesimal, and only occurs at long 
intervals in single individuals, and that it is quite insufficient 
for natural selection to work with in the production of new 
species. 

This blindness, no doubt, arose in some persons from the 
ingrained idea of man's special creation, at all events, and that 
it was almost impious to suppose that these variations could 
have had anything to do with his development from some 
lower forms. But among naturalists the idea long prevailed, 
as it does still to some extent, that in a state of nature there 
is little variation. Yet here, too, they might have found a 
clue in the fact, so often quoted, that a shepherd knows every 
individual sheep in his flock, and the huntsman every dog in 
his well-matched pack of hounds, and this notwithstanding 
that in both cases these animals are selected breeds in which 
all large deviations from the type form are usually rejected. 

Of late years, however, variations occurring in a state of 
nature have been carefullv examined and measured, and it is 
to some of these that w^e will now appeal for the proof of ever- 
present variation of the character and amount needed for the 
production of new species and of every kind of adaptation by 
means of natural selection or the survival of the fittest. Be- 



110 



THE WOKLD OF LIFE 



fore giving examples of the variation of the higher animals 
it will be advisable to show Avhat is meant bv the " law of 
frequency " of variations which has been established by the 
measurement of several thousands of men in various countries 
of Europe. These when recorded by means of a diagram are 
found to form a very regular curve, which becomes more and 
more regular the larger are the numbers measured. The im- 
portance of this is that when we have only small numbers of 
animals to deal with, and we find great irregularity in their 
diagrams, we are sure that if we had measurements of hun- 
dreds or thousands the curves would be equally regular ; and 
this has now been found to be the case. 

The law alluded to is that the number of individuals show- 
ing any particular amount of variation is in inverse proportion 
to its departure from the mean value in the species. It is very 
closely represented by a special curve called by mathematicians 
the '' curve of eiTor," but for our purpose may be termed the 
curve of frequency. 

The diagram here given represents this curve obtained by^ 




mimm 



^i^V:::^::::::.::..:... 



Dwarfs. Average Men Giant*. 

CURVE OF STATURE. (BRITISH). 

Fig. 9.— Diagi-am of Heiglit of 2600 Men. 

measuring the heights of a large number of men taken at 
random. 

The horizontal scale shows the heights given in feet and 
inches, and the vertical scale the numbers measured of suc- 
cessive heights. The central line through the highest point of 



HEEEDITY, ViVEIATIOE" 117 

the curve marks the average of the whole number measured, 
there being in this case (though not always) very nearly 
the same number of individuals above and below the mean 
height. 

The peculiarity of the curve is that it rises very slowly from 
the height marking that of the shortest individual measured — 
here a fraction above 4 feet 8 inches — then more and more 
rapidly for about one-third of the height, then more rapidly 
and nearly regularly to near the summit, when it bends in 
rather abruptly to the mean height, and then descends in a 
nearly corresponding curve as heights are above the average, 
till it ends just short of 6 feet 8 inches. 

By adding together the numbers on both sides of the curve 
we find that in this particular group of 2600 men none were 
quite so short as 4 feet 8 inches or quite so tall as 6 feet 8 
inches. But in any other group of the same number the ex- 
tremes might be a little more or less, perhaps a quarter of 
an inch or rarely a whole inch. We should have to measure 
a million, or even several millions, to get the average height 
and the proportionate greatest and least heights ; and even then 
we should not get near the absolute limits of our race, as we 
know that at long intervals giants and dwarfs appear, differing 
by many inches, or even by a foot, from all others living at 
the time. But, omitting these rare occurrences, the measure- 
ments of a few thousand among a fairly mixed population will 
give us the mean height of the whole, very nearh^; as well 
as the proportionate numbers of those of particular heights, 
as, for example, at 5 feet 3 inches or 6 feet 3 inches. But 
even the mean height does not remain the same if the mode 
of life changes. It is certain that the larger proportion now 
living in crowded cities than there were a century ago has 
considerably dwarfed our population. 

We will now give an example of variation in a wild 
animal in order to show that man and the animals and plants 
which he has domesticated or cultivated do not differ in this 
respect from those existing in a state of nature. 



118 



THE WORLD OF LIFE 



The diagram here given is formed from the measurements 
of six separate portions of twenty male specimens of the Bob- 
o'-link or Rice-bird (Dolichonyx oryzivorus)^ very common in 
I^orth America. All were obtained in the same place on the 
same day, so that there could be no suspicion of their being 



Inches 
6 i 2 



g JO ]] 22 23 24 25 26 27 28 J9 20 5 




1 2 3 4 5 6 7 3 9 lO 22 22 23 14 J3 16 27 28 29 20 

Rice-hird ( Dolicho2iyX'Oryz2voras .J 30 Males 



Fig. 10, — Diagram of Variation. 



HEKEDITY, VAlUATiOiV 119 

in anv way selected as especially variable. It is a little larger 
than our yellow-hammer^ and is therefore of a convenient 
size to be shown on a diagram of its actual dimensions, thus 
giving a better notion of the amount of variation of the several 
parts than if reduced to a smaller scale. 

The vertical lines, numbered at top and bottom, 1-20, show 
the measurements of the tw^enty specimens of this bird, and 
the figures at the sides, 0-5, mark the inches. The specimens 
are arranged in the order of length of body, shown by the 
upper somewhat irregularly curved line of dots. This is seen 
to vary from 4% inches to a little less than 5 inches. The 
next lower line show^s the length of the wing of each specimen, 
and we at once see the want of correspondence with that of 
the body. ^o. 5, w^ith a quite short body, has the longest 
wing of all; while No. 16, with a long body, has nearly the 
shortest wing. The third line, showdng the tail-lengths, is 
equally remarkable, for No. 6 shows the longest tail with quite 
a short body, while No. 16, with one of the shortest tails, has 
a long body; so that Nos. 6 and 16, measured in the usual way 
to the end of the tail, would be found of exactly the same size, 
though the one is really % inch shorter than the other. 

The next three lines show the varying lengths of the tarsus 
(commonly termed the leg), the middle toe, and the outer toe, 
and they too show very distinct and often contrasted divergences 
in proportion to their small total length. Thus Nos. 11 and 18 
have nearly the shortest legs with large bodies. The middle 
toe in 7 is as long as in 19 and 20, while the outer toe is 
decidedly longer than in 19, and in 12 decidedly shorter than 
in 2. 

It is particularly important to note here that this remarkable 
amount of variation occurs in only tw^enty birds taken at 
random. But the species is one of the most populous in North 
America, occurring in enormous flocks over the whole conti- 
nent, from 54° N. lat. in summer, and migrating as far south 
as Paraguay in winter. There must, therefore, be an average 
population of (probably) hundreds of millions, giving a much 



120 THE WORLD OF LIFE 

greater range of variation, and an ever-present abundance of 
variations of all the parts and organs of the species. 

In my Darwinism (chapter iii.) I have given sixteen dia- 
grams of variation, showing that it ocenrs to an approximately 
equal extent in mammals and reptiles as well as in birds, and 
in a large number of their parts and external organs; while 
many examples of variation occur among the lower animals, 
especially insects, and also to an amazing extent among plants. 
During the last twenty years an enormous amount of work 
has been done in the investigation of variation in all its phases 
and complexities, and an excellent accoimt of these has been 
given by Dr. H. M. Yernon in his Variation in Animals and 
Plants, 1903 (International Scientific Series), to which my 
readers are referred for fuller information, but a few of his 
conclusions may be here given. He says : 

" Every organism varies in respect of all its characters, what- 
ever be their nature. The amount of this variation differs greatly, 
but it is always present in a greater or less degree." 

And again, referring to a diagram showing the variations of 
a squirrel, he says: 

" Variation of a similar nature — though of a varying degree — 
is present in all organisms, to whatever class of the animal or 
vegetable kingdom they belong." 

Eef erring to the diagram of human stature at p. 116, it is 
found that about half the whole number measured vary a little 
more than 2 inches above or below the mean, or a little more 
than 3 per cent of the mean height. This is termed the per- 
centage of mean error, and Mr. Vernon gives us an interesting 
table of the same percentage for different parts of the body 
derived from very larg-e numbers of measurements of different 
races of men. It is as follows : — 



HEREDITY, VARIATION 



121 



Per cent. 

Nose length 9.46 

" breadth 7.57 

'' height 15.2 

Forehead height 10.4 

Under-jaw length 4.81 

Mouth bretidtJi 5.18 



Per cent. 

Head length 2.44 

" breadth 2.78 

Upper arm length G.50 

Fore arm length 3.85 

Upper leg length 5.00 

Lower " 5.04 

Foot length 5.92 



Here we see that the different parts of the human body vary 
more, proportionally, than does its whole height ; and we must 
always remember that these variations are all, to a large extent, 
independent of each other, just as we saw was the case with 
those parts shown in the bird diagram. 

Again Ave must lay stress upon the fact that every part of 
every organism, outside or inside, important or insignificant, 
is subject to a similar and often more pronounced amount of 
variation, as numerous examples quoted in Mr. Vernon's book 
amply prove. So that we are fully justified in accepting as a 
demonstrated fact, that the whole structure of every organism, 
in every stage of its growth or development, varies in its dif- 
ferent individuals, each one in a somewhat different manner, 
and to such a large extent as to afford the amplest store of 
material for modification and development in any direction 
that may be required. 

This ever-present and all-pei"vading variability is probably 
the most important of the contributory factors of evolution, 
and must never for a single moment be lost sight of. 

Powers of Increase of Plants and Animals 

Of almost equal importance with ever-present variation is 
the power which all organisms possess of reproducing their 
kind so rapidly as to be able to take possession of any unoc- 
cupied spaces around them, and in many cases to expel other 
kinds by the vigour of their growth. 

The rapidity of increase is most prominently seen among 
vegetables. These are capable, not only of a fivefold nr ten- 
fold annual increase, as am<^iii:- many of the higher animals, 



122 THE WORLD OF LIFE 

but one of many hundred or even thousandfold annually. A 
full-grown oak or beech tree is often laden with fruit on every 
branch, which must often reach 100,000, and sometimes per- 
haps a million in number, each acorn or nut being capable, 
under favourable conditions, of growing into a tree like its 
parent. Our wild cherries, hawthorns, and many other trees, 
are almost equally abundant fruit-bearers, but in all these cases 
it is only rarely (in a state of nature) that any one seed grows 
to a fruit-bearing size, because, all having a superabundance 
of reproductive power, an equilibrium has been reached every- 
where, and it is only when some vacancy occurs, as when a 
tempest uproots or destroys a number of trees, or some diminu- 
tion of grazing animals allows more seedlings than usual to 
grow up, that any of the seeds of the various trees around 
have a chance of sun'iving; and the most vigorous of these 
wall fill up the various gaps that have been produced. 

But it is among the herbaceous plants that perhaps even 
gi'eater powers of increase exist. Where our common fox-glove 
luxuriates we often see its tall spikes densely packed with 
capsules, each crowded with hundreds of minute seeds, which 
are scattered by the wind over the surrounding fields, but only 
a few which are carried to especially favourable spots serve 
to keep up the supply of plants. Kerncr, in his Xatural His- 
tory of Plants, tells us that a crucifer, Sisymhrium Sophia, 
has been found to produce on an average 730,000 seeds, so that 
if vacant spaces of suitable land existed around it, one plant 
might, in three years only, cover an area equal to 2000 times 
that of the land-surface of the globe. A close ally of this, 
Sisymhrium Irio, is said to have sprung up abundantly among 
the ruins of London after the great fire of 1666. Yet it is 
not a common plant, and is a doubtful native, only occurring 
occasionallv in En2^1ish localities. 

Turning to the animal kingdom, we still find the repro- 
ductive powers always large and often enonnous. The slowest 
breeding of all is the elephant, which is supposed to rear one 
young one every 10 years ; but, as it lives to more than 100 



HEEEDITY, VAEIATION 123 

years, Darwin calculates, that in 750 years (a few mouients 
only in the geological history of the earth) each pair wuiikl, 
if all their offspring lived and bred, produce 19 millions of 
elephants. 

The smaller mammals and most birds increase much more 
rapidly, as many of them produce two or more families every 
year. The rabbit is one of the most rapid, and ^Ir. Kearton 
calculates that, under the most favourable conditions, a single 
pair might in 4 or 5 years increase to a million. Australia, 
being favourable in climate, vegetation, and absence of ene- 
mies, they have so multiplied as to become a nuisance and 
almost a danger, and though their introduction was easy, it 
has so far been found impossible to get rid of them. 

When the general adaptation of an animal to its whole con- 
ditions of life over a large area is favourable, an enormous 
population can permanently maintain itself in the face of what 
appear to be dangerous enemies. Two cases illustrate this, and 
at the same time show how the presence of civilised man leads 
to their rapid extinction. 

In the eighteenth century the bison ranged over almost the 
w^hole of temperate Xorth America, being abundant in Penn- 
sylvania and Kentucky, as well as over the whole of the central 
plains, while it sometimes extended to the coast of the Atlantic. 
Within the memor)^ of living persons it abounded west of the 
Mississippi in countless herds many miles in extent, as vividly 
described by Catlin the painter, in the stories of Mayne Reid, 
and in the narratives of numerous travellers and explorers. 

The fact that such a large and rather clumsy animal should 
under natural conditions have occupied so large an area in 
such vast multitudes, is a sure proof that it had become so 
perfectly adapted to its whole environment as to effectually 
protect itself against the numerous enemies that inhabited the 
same area. Those powerful members of the cat tribe, the 
jaguar and the puma, would have been quite able to destroy 
the bison had it not been protected by its social instinct and 
high intelligence. The wolves which hunt in packs, and are 



124 



THE WOraD OF LIFE 



equally po^verful and ferocious mth those of Europe, must 
also have been most dangerous enemies; but the bisons always 
associated in numerous herds, and were so well guarded by the 
old males, that they apj^ear to have suffered little from these 
animals. The immense shaggy covering to the head, neck, 




Fig. 11. — The American Bison {Bos Americanus) . 

and breast of the male buffaloes, together with their short, 
powerful horns, were an almost perfect protection ; and we 
must consider these animals to have constituted one of the 
highest developments of the great tribe of herbivorous quadru- 
peds. 

The extension of railways over the whole country about the 
middle of the century, and the fact that, as the herds dimin- 
ished buffalo skins became more valuable, led to its rapid 
extermination ; and at the present time only a small and d^\'in- 
dling herd exists in the Yellowstone Park, and another in 
north-western Canada. 

Even more remarkable has been the disappearance of the 
passenger pigeon (Ectopistcs migratoria), so called from its 
great powers of flight and its migration in vast flocks all over 
Xorth America. The population of this bird was almost in- 
credibly great, as described by the American ornithologists 
Audubon and Wilson in the early part of the nineteenth cen- 



HEREDITY, VARIATIOX 125 

tiiry. It inhabited the whole of the wooded parts of Xorth 
America from Mexico, within the tropic?, to the northern 
shores of Ilndson's Bay, and its former history is now tlie more 
interesting, because it has already become a creature of the 
past. In the American periodical. The Auk, of last year, is 
the following note : 

''The Passenger Pigeox — only One Pair left. — I have 
taken a special interest in the remaining birds belonging to the 
Milwaukee and Cincinnati flocks which have been in confinement 
for many years. In my last remarks on the species (Auk, 1908, 
p. 18) I stated that the remnants of these flocks then numbered 
but seven birds, with little or no chance of further reproduction. 
The number is now reduced to a single pair, and doubtless the 
months are numbered when this noble bird must be recorded as 
extinct. — Ruthven Deane, Chicago, 111.'' 

In view of the above statement it ^\i\\ be both interesting 
and instructive to state briefly what were the facts as to the 
numbers of these birds about a hundred years ago (1811). 
Alexander Wilson gives the following account in his American 
Ornithology : 

" The roosting-places are always in the woods, and sometimes 
occupy a large extent of forest. "When they have occupied one of 
these places for some time tlie appearance it presents is surprising. 
The ground is covered to the depth of several inches with their 
dung; all the tender grass and underwood destroyed; the surface 
strewed with large limbs of trees broken down by the weight of tlie 
birds collecting one above another ; and the trees themselves for 
thousands of acres killed as completely as if girdled with an axe. 
The marks of their desolation remain for many years. When these 
roosts are first discovered, the inhabitants from considerable dis- 
tances visit them in the night, with guns, clubs, long poles, pots of 
sulphur, and various other engines of destruction. In a few liours 
they fill many sacks and load horses with them. 

"The breeding-place differs from the roost in its greater extent. 
In the western countries, viz., the States of Ohio. Kentucky, and 
Indiana, these are genei-allv in backwoods, and often extend in 



126 THE WORLD OF LIFE 

neai'h^ a straight line across the country for a great distance. Not 
far from Shelby villc;, in the State of Kentucky, about five years ago, 
there was one of these breeding-places which stretched through the 
woods in nearl}^ a north and south direction, was several miles in 
breadth, and was said to be upwards of forty miles in extent. In 
this tract almost everv tree was furnished with nests wherever the 
branches could accommodate them. The pigeons made their first 
appearance there about the 10th of April, and left it altogether 
with their young before the 25th of May. As soon as the young 
were fully grown, and before they left the nests, numerous parties 
of the inhabitants from all parts of the adjacent country came with 
wagons, axes, beds, cooking utensils, many of them accompanied by 
the greater part of their families, and encamped for several days at 
this immense nursery. Several of them informed me that the noise 
was so great as to terrify their horses, and that it was difficult for 
one person to hear another speak without bawling in his ear. The 
ground was strewed wath broken limbs of trees, eggs, and young 
squab pigeons, which had been precipitated from above, and on 
which herds of hogs were fattening. Hawks, buzzards, and eagles 
were sailing about in great numbers, and seizing the squabs from 
the nests at pleasure, while from twenty feet upwards to the top 
of the trees the view through the woods presented a perpetual tumult 
of crowding and fluttering multitudes of pigeons, their wings roar- 
ing like thunder, mingled with the frequent crash of fallen timber ; 
for now the axe-men were at work, cutting down those trees that 
seemed to be most crowded with nests, and contrived to fell them 
in such a manner that in their descent they might bring down 
several others, by which means the falling of one large tree some- 
times produced 200 squabs, little inferior in size to the old ones 
and almost one heap of fat. It was dangerous to walk under these 
flying and fluttering millions from the frequent fall of large 
branches, broken down by the weight of the multitudes above, and 
which in their descent often destroyed numbers of the birds them- 
selves, while the clothes of those traversing the woods were com- 
pletely covered with the excrements of the pigeons. 

" I passed for several miles through this same breeding-place, 
where every tree was spotted with nests, the remains of those above 
described. In manv instances I counted upwards of ninety nests 
in a single tree; but the pigeons had abandoned this place for 



HEREDITY, VAEIATIOK 127 

another, sixty or eighty miles oIT, towards Green river, where they 
were said at tliat time to he equally numerous. From the great 
numbers that were continually passing over our heads to or from 
that quarter, I had no doubt of the truth of this statement. The 
mast had been chiefly consumed in Kentucky; and the pigeons, 
every morning a little before sunrise, set out for the Indiana terri- 
tory, the nearest part of which w^as about sixty miles distant. 
Many of these returned before ten o'clock, and the great body 
generally appeared on their return a little after noon. I had left 
the public road to visit the remains of the breeding-place near 
Shelbyville, and was traversing the woods with my gun, on my way 
to Frankfort, when about ten o'clock, the pigeons which I had 
observed flying the greater part of the morning northerly, began 
to return in such immense numbers as I never before had witnessed. 
Coming to an opening by the side of a creek called the Benson, 
where I had a more uninterrupted view, I was astonished at their 
appearance; they were flying with great steadiness and rapidity, at 
a height beyond gunshot, in several strata deep, and so close to- 
gether that, could shot have reached them one discharge could not 
have failed bringing down several birds. From right to left as far 
as the eye could reach, the breadth of this vast procession extended, 
seeming everywhere equally crowded. Curious to determine how 
long this appearance would continue, I took out my watch to note 
the time, and sat down to observe them. It was then half-past one ; 
I sat for more than an hour, but instead of a diminution of this 
prodigious procession it seemed rather to increase, both in numbers 
and rapidity, and anxious to reach Frankfort before night, I rose 
and went on. About four o'clock in the afternoon I crossed 
Kentucky river, at the town of Frankfort, at which time the living 
torrent above my head seemed as numerous and extensive as ever. 
Long after this I observed them in large bodies that continued to 
pass for six or eight minutes, and these again were followed by 
other detached bodies, all moving in the same south-east direction 
till after six o'clock in the evening. The great breadth of front 
which this mighty multitude preserved would seem to intimate a 
corresponding breadth of their breeding-place, wdiich, by several 
gentlemen w^ho had lately passed through part of it, was stated to 
me as several miles." 



128 THE WOr.LD OF LIFE 

Wilson then gives a rongli calciilation of the probahle num- 
bers of this great flight of pigeons, and comes to the conclusion 
that its whole length was 240 miles, and that the number of 
birds must have been considerably more than 2000 millions. 
If each pigeon consumed only half a pint of food daily, the 
quantity would amount to over IT millions of bushels daily. 
Audubon, who went throu2;h the same country about twentv 

7 ~ 1-1/ 

years later, confirms Wilson's account in every essential part ; 
and the language of the former is so simple and restrained, 
that there is evidently no attempt to exaggerate what he wit- 
nessed and was informed of by many independent observers. 
Waterton, with his usual scepticism as to the observations of 
other naturalists, treats the whole narrative as gross exaggera- 
tion or fabrication ; on which the late Professor Alfred Xewton 
remarks, that the critic would probably have been less severe 
had he known that, 150 years earlier, these pigeons so swarmed 
and ravaged the colonists' crops near Montreal, that a bishop 
of his own Church was constrained to exorcise them with holy 
water as if they had been demons. Professor Xewton adds 
that the rapid and sustained flight of these pigeons is as well 
established as their former overwhelming abundance, birds hav- 
ing been killed in the State of Xew York whose crops contained 
undigested grains of rice that must have been not long before 
plucked and swallowed in South Carolina or Georgia. The 
passenger pigeon has several times been shot in Great Britain, 
and Professor Xewton believes that some of these crossed the 
Atlantic unassisted by man. 

Considering the vast multitudes of these birds in a state of 
nature, notwithstanding the variety of birds of prey in Xorth 
America, together with its unequalled powers of flight, it must 
be classed as one of the finest examples of what DarAvin termed 
" dominant species," and may also be considered as the highest 
development of the special type of bird-life manifested in the 
order Columbse or Pigeons ; and it will doubtless, by future 
generations of bird-lovers, be counted as a blot upon the boasted 
civilisation of the nineteenth century that, in its mad greed 



HEREDITY, VARIATION 



129 



for wealth, it should have so devastated a whole continent as 
not to leave room in it for the continued existence of such 
grand and beautiful life-fomis as the bison and passenger 
pigeon. 

Equally remarkable, perhaps, is the Norwegian lemming, a 
little animal somewhat larger than our short-tailed field-mouse, 




Fig. 12. — The Lemming {Myodes lemmus). 

but with a tail only half an inch long. This creature is always 
abundant in Lapland and northern Scandinavia, but only ex- 
traordinarily so at long intervals, when favourable conditions 
lead to its almost incredible multiplication. At intervals of 
from ten to twenty-five years a great army of them appears, 
which devours every green thing in its path. Great bands 
descending from the highlands of Lapland and Finland march 
in parallel lines about 3 feet apart, never turning aside, cross- 
ing lakes, and rivers, and even eating through com and hay- 
stacks when these cross their path. The following recent 



130 THE WOELD OF LIFE 

statement of the ascertained facts as to these strange migra- 
tions — from the work on Mammals by the late Sir H. Flower 
and E. Lydekker — will prove interesting: 

" The -usual dwelling-place of the Lemmings is in the highlands 
or fells of the great central mountain chain of Norway and Sweden. 
South of the Arctic circle, they are, under ordinary circumstances, 
exclusively confined to the plateaus covered with dwarf birch and 
juniper above the conifer region, though in Tromso and Finmarken 
they occur in all suitable places down to the level of the sea. The 
nest is found under a tussock of dry grass or a stone, constructed of 
dry straws and usually lined with hair. The number of young in 
each nest is generally five, and at least two broods are produced 
annually. Their food is entirely vegetable, especially grass roots 
and stalks, shoots of the birch, reindeer-lichen and mosses, in search 
of which they form in winter long galleries through the turf or 
under the snow. They are restless, courageous, and pugnacious 
little animals. AMien suddenly disturbed, instead of trying to es- 
cape, they will sit upright, with their back against a stone or other 
object, hissing or showing fight in a very determined manner. 
(See Fig. 12.) 

" The circumstance which has given more popular interest to 
the Lemming than to a host of other species of the same order of 
animals is that certain districts of the cultivated lands of iSTorway 
and Sweden, where in ordinary circumstances they are quite un- 
known, are occasionally and at very uncertain intervals, varying 
from five to twent}^ or more years, literally overrun by an army of 
these little creatures, which steadily and slowly advance, always in 
the same direction, and regardless of all obstacles, swimming across 
rivers and even lakes of several miles in breadth, and committing 
considerable devastation on their line of march by the quantity of 
food they consume. In their turn they are pursued and harassed 
by a crowd of beasts and birds of prey, as bears, wolves, foxes, dogs, 
wild cats, stoats, weasels, hawks, and owls, and are never spared by 
man; even the domestic animals not usually predaceous, as cattle, 
goats, and reindeer, are said to join in the destruction, stamping 
them to the ground with their feet, and even eating their bodies. 
Numbers also die from diseases apparently produced by overcrowd- 
ing. None ever return by the course over which they have come. 



HEEEDITY, VARIATION 131 

and the onward march of the survivors never ceases until they reach 
the sea, into which they plunge, and swimming outwards in the 
same direction as before, perish in the waves. ... So extraor- 
dinary was the sudden appearance of these vast bodies of Lem- 
mings to the Norwegian peasants, that they supposed they must 
have fallen from tiie clouds. 

" The principal really ascertained facts regarding these migra- 
tions seem to be as follows : When a combination of favourable 
circumstances has occasioned a great increase in the numbers of 
Lenmiings in their ordinary dwelling-places, a movement neces- 
sarily occurs at the edge of the elevated plateau, and a migration 
towards the low-lying land begins. The whole body slowly moves 
forward, advancing in the same general direction in which they 
started, but following more or less the course of the great valleys. 
They only travel by night, and they also stay in congenial places 
for weeks or months, so that, with unaccustomed abundance of 
food, notwithstanding all the destructive influences to which they 
are exposed, they multiply excessively during their journey, having 
families still more numerous and more frequently than in their 
usual homes. The progress may last from one to three years, ac- 
cording to the route taken and the distance to be traversed until 
the sea coast is reached, which, in a country so surrounded by 
water as the Scandinavian peninsula, must be the ultimate goal of 
such a Journey. This may be either the Atlantic or the Gulf of 
Bothnia, according as the migration has commenced from the west 
or east side of the elevated plateau. Those that finally perish in 
the sea are only acting under the same blind impulse which has 
led them previously to cross smaller pieces of water with safety." 

The strange history of these small creatures, besides showing 
the enormous powers of increase in various types of life, also 
furnishes us with a fine example of adaptation to what would 
be, to most animals, extremely adverse conditions — high 
plateaus within or bordering on the Arctic circle, with its 
intense cold, its long periods of darkness, buried in snow in 
winter and with a scantv and stunted vegetation. Yet thev 
appear to have a most enjoyable existence, and would evidently 
be able to overrun and occupy a much larger extent of sim- 



132 THE WORLD OF LIFE 

ilarly inhospitable country did such exist in their vicinity; 
while in more fertile lands, with a milder climate and more 
luxuriant vegetation, they rapidly become extinct through dis- 
ease or the attacks of enemies. 

In Mr. W. II. Hudson's most interesting volume, A Nat- 
uralist in La Plata, he gives an account of a very similar rapid 
increase of field-mice, under extremely different conditions, in 
the chapter entitled A Wave of Life. In a concluding pas- 
sage he so clearly summarises the whole course of events that 
I here extract it : — 

" Cover and food without limit- enabled the mice to increase at 
such an amazing rate, that the ordinary checks interposed by pred- 
atory species were for a while inappreciable. But as the mice 
increased so did their enemies. Insectivorous and other species 
acquired the habits of owls and weasels, preying exclusively on 
them; while to this an innumerable array of residents was shortly 
added multitudes of wandering birds coming from distant regions. 
'No sooner had the herbage perished, depriving the little victims of 
their cover and food, than the effects of the war became apparent. 
In autumn the earth so teemed with them that one could scarcely 
walk anywhere without treading on mice ; while out of every hollow 
weed-stalk lying on the ground dozens could be shaken; but so 
rapidly had they been devoured by the trained army of persecutors 
that in spring it was hard to find a survivor even in the barns and 
houses. The fact that species tend to increase in a geometrical 
ratio makes these great and sudden changes frequent in man}^ parts 
of the earth; but it is not often that they present themselves so 
vividly as in the foregoing instance, for here, scene after scene in 
one of l^ature's silent, passionless tragedies, myriads of highly 
organised beings rising into existence only to perish almost imme- 
diately, scarcely a hard-pressed remnant surviving to continue the 
species." 

It may, however, be concluded that not thus are species 
exterminated in any region that remains suitable for their 
existence. Long before they approach extinction, the very 
scarcity of them drives away, one after another, the crowd of 



HEEEDITY, YAEIATION" 133 

enemies whicli had been attracted by their inordinate num- 
berSj till the former balance of life is restored, and the rapid 
powers of increase of the sufferers soon restores them to their 
normal population. It is against the adverse powers of inor- 
ganic nature that speedy reproduction is such a safe-guard. 
When fire or flood, droughts or volcanic outbursts have de- 
stroyed animal life over wide areas, the few survivors on the 
margin of the devastated area are able to keep pace with 
renewed vegetation and again stock the land with its former 
variety of living things. 

The facts outlined in the present chapter, of abundant and 
ever-present variability with enormous rapidity of increase, 
furnish a sufficient reply to those ill-informed writers who still 
keep up the parrot-cry that the Darwinian theory is insuffi- 
cient to explain the formation of new species by survival of 
the fittest. 

They also serve to rule out of court, as hopelessly inefficient, 
the modern theories of ^' mutation " and " mendelism,'' which 
depend upon such comparatively rare phenomena as " sports '' 
and abnormalities, and are, therefore, ludicrously inadequate 
as substitutes for the Darwinian factors in the world-wide and 
ever-acting processes of the preservation and continuous adap- 
tation of all living things. The phenomena upon which these 
theories are founded seem to me to be mere insifmificant bve- 
products of heredity, and to be essentially rather self-destruc- 
tive than preservative. They form one of nature's methods of 
getting rid of abnormal and injurious variations. The per- 
sistency of Mendelian characters is the veiy opposite of what 
is needed amid the ever-changing conditions of nature.^ 

1 A critical examination of these theories is gjiven in Mr. G. Archdall 
Reid's recent work, The Principles of Heredity. There is also a shorter and 
more popular criticism in the Introduction to Professor E. B. Poiilton's 
Essays on Evolution (1908). 



CHAPTER VIII 

ILLUSTRATIVE CASES OF NATURAL SELECTION AND ADAPTATION 

We have now learnt something of the great features of the 
^' world of life " whose origin, development, and meaning we 
are seeking to comprehend ; we have been enabled to visualize 
its enormous extent, its almost endless diversity of form, struc- 
ture, and mode of existence; the vast population of the species 
that compose it, especially those which we term common. 
Further, we have seen something of the way in which large 
numbers of species inhabit the same area intermingled to- 
gether, which they are enabled to do by each being adapted 
to some one station or particular kind of food which its peculiar 
organisation enables it to utilise; each occupying, as it were, 
a special place in the economy of nature. 

We have also learnt something of the three great factors which 
are essential for the gradual modification of species into new 
and better adapted organisms — heredity, variation, and enor- 
mous powers of increase, leading inevitably to a struggle for 
existence, since of the many that are born only a few can 
possibly survive. We are, therefore, now prepared to exam- 
ine, so far as we are able, the exact method of Nature's work 
in species-production. 

One of the difficulties in the way of an acceptance of con- 
tinuous evolution through variation and natural selection is, 
that though variation may be fully admitted, and though great 
changes of climate and some changes of land and sea have 
occurred in the human period, these do not seem to have led 
to the foraiation of new species, but only to the extinction, 
or change in the distribution, of a few of them. But of late 
years naturalists, having pretty well exhausted the well-defined 
species of the best-known parts of the world — Europe and 

134 



CASES OF ADAPTATION 135 

iN'ortli America — have j^aid more attention to varieties, and 
especially to those characteristic of islands or other well- 
marked and somewhat isolated districts. 

Having been much struck, some forty years ago, by the fact 
that two peculiar beetles are found in Lundy Island (in the 
Bristol Channel), another in Shetland, while some peculiar 
forms of butterflies and moths occurred in the Isle of ^Alan, I 
thought it would be interesting to collect together and publish 
lists of all the species or varieties of animals and plants whicli 
had hitherto been found only in our Islands. This I attempted 
when writing my Island Life in 1880 and several specialists 
in various groups were kind enough to draw up lists for me. 
These were revised and much increased in the second and third 
editions; and in the latter (1902) they amounted to 5 birds, 
14 fresh-water fishes, 179 lepidoptera, 71 beetles, 122 land 
and fresh-water molluscs, and 86 flowering plants. It is inter- 
esting to note that of these latter no less than 20 are found only 
in Ireland, where the insular conditions of climate that may 
be supposed to lead to modification are at a maximum. Xo 
less than 20 species of our Mosses and 27 of our Ilepaticse are 
also not found in Europe, though a few of them are (and others 
may be) found in other parts of the world. 

As there is no doubt that our islands were at no distant 
period (in a geological sense) united to the continent, and 
that since their separation they must, through the influence 
of the Gulf Stream penetrating around and among them, have 
acquired a milder, moister, and a more uniform climate, it 
seems quite probable that a considerable proportion of these 
numerous local forms are actual modifications of the allied 
continental forms due to adaptation to the changed conditions. 

Since my book was published, an interesting addition to the 
list of peculiar birds has been made by Dr. Ernst Ilartert, in 
an article entitled On Birds represented in the British Isles, 
by peculiar Forms. In this list, with MSS. additions up to 
the end of 1909, Dr. Hartert enumerates no less than 21 spe- 
cies, which have become more or less distinctly modified from 



136 THE WOELD OF LIFE 

their continental allies. These include a distinct crossbill from 
the highlands of Scotland, all our British titmice, which seem 
to be especially modifiable, and several others. The complete 
list is as follows : — 

1. Pyrrhula pyrrhula pileata British Bullfinch. 

2. Turdus musicus clarkei " Song-Thrush. 

3. Pratincola rubicola hibernaeus " Stonechat. 

4. Garrulus glandarius riifitergum .... " Jay. 

5. Loxia curvirostra scotica Scottish Crossbill. 

6. Carduelis carduelis britannicus British Goldfinch. 

7. Motacilla flava rayi Yellow Wagtail. 

8. " alba lugubris Pied Wagtail. 

9. Parus major newtoni British Great Titmouse. 



10. 
11. 
12. 
13. 
14. 



cieruleus obscurus " Blue Titmouse. 

ater britannicus " Coal Titmouse. 

palustris dresseri " Marsh Titmouse. 

atricapillus kleinschmidti . . . . " Willow Titmouse, 
cristatus scotica Scottish Crested Titmouse. 



15. Aegithalus caudatus rosea British Long-tailed Titmouse. 

16. Regulus regulus anglorum " Goldcrest. 

17. Sitta europaea britannica " Nuthatch. 

18. Certhia familiaris britannica " Tree-creeper. 

19. Erithacus rubecula melophilus " Robin. 

20. Troglodytes troglodytes pirtensis , . St. Kilda Wren. 

21. Cinclus cinclus britannicus British Dipper. 

22. Dendrocopus major anglicus " Great Spotted Woodpecker 

23. " minor comminutus " Lesser Spotted Wood- 

pecker. 

24. Lagopus lagopus scoticus Bed Grouse. 

This last has been generally treated as a well-marked species, 
but Dr. Hartert considers it, with all the others, to be a sub- 
species — a species in the making. It is certainly a very inter- 
esting fact that so many of our familiar birds are found to 
present constant differences from their continental allies. 
Most of these differences are of colour only, but some diversity 
of bulk and in the size of the bill indicate the commencement 
of structural modification; and these various differences from 
the nearest continental species in so many of our resident birds 
seem inexplicable on any other theory than that they are adap- 
tations to the slight but undoubted difference of climatical con- 
ditions which characterise our islands. 



CASES OF ADAPTATION 137 

In confirmation of this view, a few cases have been recorded 
in which nature has been caught, as it were, at work in the 
actual formation of new species at the present time. The 
first is that of the Porto Santo rabbits, carefully investigated 
by Darwin. In the history of an early Spanish voyage it is 
recorded that, a female rabbit having had a litter of young 
on board, they were all turned loose on this small uninhabited 
island near Madeira. This was about 1419, and from these 
alone the island became fully stocked, and remains so still, 
although the island is now fairly peopled. Darwin was able 
to examine two of these rabbits preserved in spirits, three 
others in brine, and two alive which had been in the Zoological 
Gardens for four years. These seven specimens, though caught 
at different times, closely resembled each other, they were all 
full grown, yet they were very much smaller than English 
wild rabbits, being little more than half the weight, and nearly 
three inches less in length. Four skulls of the Porto Santo 
rabbits diifered from those of English vdld rabbits in the supra- 
orbital processes of the frontal bone being narrower; but they 
differed considerably in colour, the upper surface being redder, 
and the lower surface pale grey or lead colour instead of white ; 
the upper surface of the tail, however, was reddish-brown in- 
stead of blackish-grey as in all wild European rabbits, while 
the tips of the ears had no black edging, as our rabbits always 
have. 

We have here a very remarkable series of differences in size, 
colour, and even in the form of the skull ; while it was noticed 
at the Zoological Gardens that they were unusually wild and 
active, and also more nocturnal in their habits than common 
wild rabbits. In this case, these rabbits would certainlv have 
been described as a distinct species if they had been found 
in some more remote country to which it was certain that they 
had not been introduced by man. 

Another example which shows nature at work, this time in 
the actual process of " selection " of the better adapted indi- 
viduals, occurred quite recently. In February 1898, at the 



138 THE WORLD OE LIFE 

Brown University, Providence, Rhode Island, after a very 
severe storm of snow, sleet, and rain, 136 common sparrows 
were found benumbed on the ground, and were collected and 
brought to the Anatomical Laboratory. They were laid on 
the floor of a warmed room to see if any of them were alive, 
where after a short time 72 of them revived while 64 perished. 
The happy thought occurred to Professor LI. C. Bumpus, that 
here was an opportunity of discovering whether there were any 
visible characters indicating why some of these birds, under 
exactly similar conditions, w^ere destroyed while others sur- 
vived. He therefore made a very minute and careful exami- 
nation of all the birds, living and dead, with very interesting 
results, of which the following is a summary: 

(1) Sex. — About two- thirds were males, one-third females. 
Of the former 51 lived, 36 died; of the latter 21 lived, 28 
died, showing a decided superiority of the males in resisting 
cold and wet. 

(2) Size. — Here the comparison was made of male adult 
birds, male young, and females, separately; in all three of 
these groups those which died were larger than those which 
sundved. The difference was not very great, but it was clearly 
marked, and as it occurred in all three groups it could not 
possibly be imputed to chance. 

(3) Weight. — This gives the same result as in the last case, 
the survivors being lighter than those w^hich died, by the con- 
siderable proportion of one twenty-fifth. 

(4) Length of the Sternum (breast-bone). — This character 
gives a rather unexpected result, those birds which survived 
having a decidedly longer sternum than those which perished. 
The difference is about .013 (a little more than one-hundredth) 
of the total length; but as the smaller birds on the whole 
survived, these evidently had their sterna proportionally very 
long. ]^ow the sternum is an indication of the size of the 
pectoral muscles w^hich move the wings in flight. The sur- 
viving birds therefore were those that could fly quickest and 
longest, and this probably led to the more rapid production 



CASES OF ADAPTATION 139 

of animal heat. Another advantage would be, that these 
muscles being larger proportionally there would be less ex- 
posure of the internal organs to the extreme cold. 

The result of this interesting experiment is almost conclu- 
sive as to the reality of natural selection. In this case those 
which actually survived one of nature's most common tests — 
exposure to severe storms — and which must be presumed to 
have been the '' fittest " at that particular time and place, were 
found to differ in just such characters, and in such moderate 
proportions as have been found to occur constantly in all the 
commoner species of birds, as well as of all other animals. It 
proves also that such small variations are, as Professor Lloyd 
Morgan terms it, of " survival value," a fact which is con- 
stantly denied on purely theoretical grounds. 

It will perhaps make the subject a little clearer if I here 
enumerate briefly the exact causes which must have been at 
work in bringing about the changes in the rabbits of Porto 
Santo during the four and a half centuries that had elapsed 
from the time they were turned loose upon the island to the 
period when Darwin obtained his specimens. The island has 
an area of about 20 square miles ; it is very hilly, of volcanic 
origin, with a dry climate and scanty vegetation. It is about 
26 miles from Madeira, 400 from Africa, and 250 from the 
Canary Islands. The powers of increase of rabbits being so 
great, and the island being at that time uninhabited, they 
would certainly in a very few years have increased to so great 
a multitude as to consume all the available vegetation. As 
they approached to these numbers, and were obliged to expose 
themselves in the daily search for food, many birds of prey 
from the larger island, and probably others from the Canaries 
and from Africa — hawks, buzzards, falcons, and owls — 
would flock to this hitherto desert island to feed upon them, 
and would rapidly reduce their numbers. 

Up to this time, perhaps not more than a dozen or twenty 
years from their first introduction, they would have varied in 
size and colour as do the common domesticated rabbits from 



140 THE WOELD OF LIFE 

which Darwin thinks they w^ere nndonbtedly derived. Their 
numerous enemies would at first capture the larger, more bulky, 
and slower-moving individuals, then the white or black speci- 
mens, who would be more easily seen and pounced upon. This 
process, continuously acting for a few generations, would result 
in a smaller and more dusky-coloured race. The continuous 
attack persisting, the size would be again reduced, and the most 
agile and rapid in movement would alone survive. There- 
after, the nocturnal habit would be acquired by the day-feeders 
being almost exterminated, and owls would probably alone 
remain as formidable enemies. Lastly, the extreme wildness, 
sensitiveness to danger, perhaps to noise or movement of any 
kind, would be developed, while the reduction of the supra- 
orbital process may perhaps have been beneficial by reducing the 
width of the head, and thus allowing them to enter small 
holes in the rocks more rapidly; or it may possibly be con- 
nected with the more nocturnal habits. We thus see that all 
the changes that have occurred in this interesting animal have 
no relation whatever to mere " isolation," which many writers 
still persist in claiming as a vera causa of specific change, but 
are all clearly traceable as the results of (1) rapid powers of 
multiplication; (2) that small amount of variability which 
we know" occurs in all such animals; and (3) rigid selection 
through diurnal and nocturnal birds of prey, which we have 
seen to play so large a part in keeping down the numbers of 
the passenger pigeons in ISTorth America, the lemming in Scan- 
dinavia, and the mice in La Plata. 

The two cases now adduced, showing how nature actually 
works in the production of slightly modified forms through 
" variation " and ^^ survival of the fittest " will, I think, render 
the process of species-formation sufficiently intelligible. Very 
slight inorganic agencies have here been seen at work — in one 
case a single severe storm, in the other a change to an isolated 
habitat where slightly new conditions prevailed. But when 
in the course of those periods when geological changes were 
most actively at work, larger and more permanent climatic 



CASES OF ADAPTATION 141 

changes occurred, or when more marked diversities of soil and 
vegetation, with exposure to more severe competition, were 
brought about, those modifications of the environment ^vould 
inevitably result in more marked and more varied adaptations 
of form, structure, or habits, bringing about what we every- 
where recognise as perfectly distinct species. 

In the present work I do not propose to go further into this 
matter, which has been treated with sufficient detail and with 
copious illustrations in my Darwinism and other works, as 
well as in Darwin's classical volumes. The Origin of Species 
and Animals, and Plants under Domestication. I will there- 
fore now proceed to an account of some of those broader aspects 
of adaptation in the organic world, which, so far as I am aware, 
have hitherto received little attention. 

Some Aspects of Organic Adaptation 

Though such a very obvious fact, it is not always kept in 
mind, that the entire animal world, in all its myriad manifes- 
tations, from the worm in the soil to the elephant in the forest, 
from the blind fishes of the ocean depths to the soaring sky- 
lark, depends absolutely on the equally vast and varied vege- 
table world for its very existence. It is also tolerably clear, 
though not quite so conclusively proved, that it is on the over- 
whelming variety of plant species, to which we have already 
called attention, that the corresponding variety of animal spe- 
cies, especially in the insect tribes, has been rendered possible. 

This will perhaps be better seen by a reference to one of 
the best-known cases of general adaptation, which, because so 
common and obvious, is often overlooked or misunderstood. 
All lovers of a garden are apt to regard as an unmitigated evil 
those swarms of insects which attack their plants in spring, and 
in recurrent bad years become a serious nuisance and commit 
widespread devastation. At one time the buds or leaves of 
their fruit trees swarm with various kinds of caterpillars, while 
at others even the oak trees are so denuded of their leaves as 
to become an eyesore in the landscape. Many of our common 



142 THE WOKLD OF LIFE 

vegetables, and even the grass on our lawns, are in some sea- 
sons destroyed bj swarms of wire-worms which feed on their 
roots. Turnips, radishes, and allied plants are attacked by 
the turnip-fly, a small jumping beetle whose larva lives in the 
leaf itself, and w^hich often swarms in millions. Then there 
are the a2:>hides and froghoppers on our roses and other shrubs 
or flowers, and grubs which attack our apples, our carrots, 
and most other crops; and all these the gardener usually re- 
gards under the general term " blight," as a serious blot on 
the face of nature, and wonders why such harmful creatures 
were permitted to exist. 

Most professional gardeners would be rather surprised to 
hear that all these insect-pests are an essential part of the world 
of life ; that their destruction would be disastrous ; and that 
without them some of the most beautiful and enjoyable of the 
living things around us would be either seriously diminished 
in numbers or totally destroyed. He might also be informed 
that he himself is a chief cause of the very evil he complains 
of, because, by growing the plants the insect-pests feed upon 
in large quantities, he provides for them a superabundance of 
food, and enables them to increase much more rapidly than 
they would do under natural conditions. 

Let us now consider what happens over our whole country 
in each recurring spring. At that delightful season our gar- 
dens and hedgerows, our orchards, woods, and copses are 
thronged with feathered songsters, resident and migratory, en- 
gaged every hour of the day in building their nests, hatching 
their eggs, or feeding and guarding their helpless offspring. 
A considerable proportion of these — thrushes, warblers, tits, 
finches, and many others — are so prolific that they have two 
or three, sometimes even more, families every year, so that 
the young birds reared annually by each pair varies from four 
or five up to ten or twenty, or even more. 

Now, when we consider that the parents of these, to the 
number of perhaps fifty species or more, are all common birds, 
which exist in our islands in numbers amounting to many 



CASES OF ADAPTATION 143 

raillions each, we can partially realise the enormous quantity 
of insect-food, required to rear perhaps five or ten times that 
number of young birds from the egg up to full growth. Al- 
most all of the young of the smaller birds, even when their 
parents are seed-eaters, absolutely require soft insect-food, such 
as caterpillars and grubs of various sorts, small worms, or such 
perfect insects as small spiders, gnats, flies, etc., which alone 
supjoly sufficient nourishment in a condensed and easily digest- 
ible form. 

Many enthusiastic observers, by means of hiding-places near 
the nests or by the use of field-glasses, have closely watched the 
whole process of feeding young birds, for hours or even for 
w^hole davs, and the results are extremelv instructive. The 
chiff-chaff, for example, feeds its young on small grubs ex- 
tracted from buds, small caterpillars, aphides, gnats, and small 
flies of various kinds ; in a nest with five young, the hen-bird 
fed them almost all day from early morning to sunset, bringing 
mouthfuls of food at an average four times in five minutes. 
This may no doubt be taken as typical of a number of the 
smaller warblers and allied birds. 

Blue tits, with a larger family, worked continuously for 
sixteen hours a day at midsummer, bringing about two thou- 
sand caterpillars to the ravenous young birds, who, taking the 
average at 10 (and they sometimes have 16) would swallow 
200 each in the day. A pair of marsh tits were observed to 
feed their young entirely with small green caterpillars, and 
in one case made 475 journeys with food in seventeen hours. 

A gold-crest with eight young brought them food 16 times 
in an hour for sixteen hours a day. A wren fed its young 
278 times in a day. Even the common house-sparrow, itself 
a typical seed-eater, feeds its young on caterpillars or on small 
insects which it catches on the wins:. A flvcatcher was ob- 
served to sit on a dead branch of an ash tree near her nest, 
whence by short flights she cauglit small flies, etc., on the 
wing, bringing a mouthful to her young every two to five min- 
utes. 



144 THE WORLD OF LIFE 

As every schoolboy knows, the number of nests is very great 
to those who know how to look for them, some being found in 
almost every wood, copse, or hedgerow. As examples, in a 
small copse in Herts, nine different species of birds had nests 
with young, all within 50 yards of each other. In another 
case, nests of a tit, a flycatcher, and a wood-wren were found 
within 10 to 15 yards of each other. In the case of many 
small birds the whole period, from hatching the eggs to that 
of the young leaving the nest is only two weeks, but swifts 
require from a month to six weeks. 

It must be remembered that the birds carefully clean out 
the nest after every meal, and in wet or very chilly weather 
carefully protect their young, and as they must also procure 
food for themselves, it is evident that their labours at this 
time are really prodigious. And this vast destruction of in- 
sect-life goes on unchecked for several months together, and 
the supply never seems to fail. When the parent birds leave 
the nest in search of food for their young, they may be seen 
to fly to some adjacent bush or branch of a tree, hop rapidly 
about it, and then perhaps fly off to another, having apparently 
decided that the first one had already been nearly exhausted. 
But in the few minutes of their absence they are always able 
to fill their mouths with small caterpillars, flics, grubs, etc., 
and return to the nest, not only from morning to night on one 
day, but the same day after day, for at least a fortnight and 
often much longer, till their first brood is fully fledged and 
able to provide for themselves. But unless the numbers of 
insects and their larvse were enormous, and were increased 
day by day by fresh hatchings from the egg as fast as they 
were devoured, hosts of these young birds would perish of 
hunger and cold. For if the parents had to range far away 
from their nests, and could not find the necessary supply so 
quickly as they do, the young birds would be subject to attack 
from some of their numerous enemies, would suffer from cold 
or wet, and as they grew older would often, in their frantic 



CASES OF ADAPTATIOX 145 

struggles with each other, fall out of the nest and quickly 
perish. 

What wonderful perfection of the senses must there be in 
these various parent birds; what acuteness of vision or of 
hearing; what rapidity of motion, and what powerful instinct 
of jDarental love, enabling them to keep up this high-pressure 
search for food, and of watchfulness of their nests and j^oung, 
on the continuance of which, and its unfailing success, the 
very existence of those young and the continuance of the race 
depends. But all this perfect adaptation in the parent birds 
would be of no avail unless the insect tribes, on which alone 
most of them are obliged to depend, were as varied, as abun- 
dant, and as omnipresent as they actually are ; and also imless 
vegetation were so luxuriant and abundant in its growth and 
so varied in its character, that it can always supply ample food 
for the insects without suffering any great or permanent injury 
to the individual plants, much less to any of the species. 

By such considerations as these we learn that what we call 
insect-pests, when they are a little more abundant than usual 
in our gardens and orchards, do not exist for themselves alone 
as an apparently superfluous and otherwise useless part of the 
great world of life, but are, and must always have been through- 
out long past geological ages, absolutely essential for the origina- 
tion and subsequent development of the most wonderful, 
delightful, and beautiful of all the living things around us — 
our garden friends and household pets, and sweet singers of 
the woods and fields. Without the myriad swarms of insects 
everywhere devouring a portion of the new and luxuriant vege- 
tation, the nightingale and the lark, the wren, the redbreast, 
and the fairy-like tits and goldcrests might never have come 
into existence, and if the supply failed would now disappear 
for ever! 

The Uses of Mosquitoes 

If now we go beyond our OAvn country and see how birds 
fare in distant lands, we find the key to many of the secrets 



146 THE WORLD OF LIFE 

of bird-life in the greater or less abundance of insects which 
supply them with food at the critical season of their lives 
when they have to supply daily and hourly food to their newly- 
hatched broods. Amid all the infinite variety of the insect 
world there is probably no one order which supplies such an 
enormous quantity of food to birds and other creatures as the 
two-winged flies (Diptera) whose larvx are the maggots which 
quickly devour all kinds of dead beasts and birds, as well as 
all kinds of putrefying animal matter ; but in the perfect state 
these insects abound in such swarms as also to supply food to 
whole groups of fly-catching birds. And among these no well- 
marked and very restricted group is at once so hateful to 
mankind and so delightful to birds as the mosquitoes. It is 
commonly supposed that these particular insect-pests are more 
especially tropical; but though they are no doubt very abun- 
dant in many parts of the tropics, yet their fullest develop- 
ment is to be found in the icy plains of the Far Xorth, espe- 
cially within the Arctic circle both in the Eastern and Western 
hemispheres. 

Sir William Butler in his w^orks — The Wild Lone Land, 
and others on Arctic and sub-Arctic Xorth America — de- 
scribes them as often swarming in such abundance as to com- 
pletely obscure the sun like a dense thundercloud ; and they 
furnish abundant material for the wildly exaggerated stories 
in which Americans delight — such as the serious statement 
that they can pierce through the thickest cow-hide boots, and 
that an Irishman, seeking protection from them by covering 
his head with a copper kettle, they pierced it in such countless 
numbers that their combined strength enabled them to fly away 
with it! 

Our best and most instructive writer on the wonderful bird- 
migrations to the Arctic regions is the late Mr. Henry See- 
bohm, who spent two seasons there, one in the north-east of 
Russia, at Ust-Zylma, and at the mouth of the Petchora River, 
far within the Arctic circle; and another in [N'orthern Siberia, 
at the mouth of the Yenesay River. He tells us, that — 



CASES OF xiDAPTxiTIOX 



147 



" Birds go to the Arctic regions to breed^ not by thousands but 
by millions. The cause of this migration is to be found in the 
lavish prodigality with which Nature has provided food. Seed or 




Fig. 


13.— 


Sh 


oo t 


ing 


Wild 


Geese 


on 


the 


Pet- 


chora 


River 


at 


Ust- 


Zylma 


(May 


14 


, 18 


75). 



fruit-eating birds find an immediate and abundant supply of cran- 
berries^ crowberries, and other ground fruit, which have remained 
frozen during the long winter, and are accessible the moment the 
snow has melted, while insect-eating birds have only to open their 
mouths to fill them with mosquitoes/' ^ 

Among the larger birds that come early to "these regions 
to breed are two species of wild swans and the bean goose. 
So early as 10th May they began to arrive, passing over Ust- 
Zylma (Lat. G6^ N.) in flocks, where, by constiiicting a shelter, 
Mr. Seebohm was able to shoot one. Even these large birds 
find ample food on the tundra to breed there ; for just before 
leaving the country, wdien near the mouth of the Petchora 

1 Siberia in Europe, p. 296. 



148 



THE WORLD OF LIFE 



Eiver, he saw them returning southward with their young. 
He writes : 

" I had not gone more than a mile when I heard the cackle of 
geese ; a bend of the river's bed gave me an opportunity of stalking 
them, and when I came within sight I beheld an extraordinary and 
interesting scene. One hundred, at least, old geese, and quite as 




Fig. 14. — Geese Moulting as they migrate South over the Tundra (July 

and August ) . 

many young ones, perhaps twice or even thrice that number, were 
marching like a regiment of soldiers. The vanguard, consisting of 
old birds, was half-way across the stream, the rear, composed 
principally of goslings, was running down the steep bank towards 
the water's edge as fast as their young legs could carry them. Both 
banks of the river where the geese had doubtless been feeding, 
were strewn with feathers, and in five minutes I picked up a 
handful of quills. The flock was evidently migrating to the 
interior of the tundra, moulting as it went along." 

This species retires southwards before the winter, and visits 
us every year in September or October being especially abun- 



CASES OF ADAPTATIO:^ 



149 



dant in Ireland, where it 
is said to be found in 
every bog and marsh. 
On the Siberian tundra 
it no doubt feeds largely 
on the abundant berries, 
but also, of course, on 
the food it finds in 
swamps and river-mar- 



gms. 



Coming back to our 
more special subject of 
the mosquitoes, Mr. See- 
bohm writes as follows. 
After describing some of 
his early excursions after 
birds or their nests he 
adds: 




Fig. 15. — Mr. Seebohm in his Mosquito 

Veil. 



" That day (June 2nd) I recorded in my journal, with many 
groans, the arrival of the mosquitoes. Horrid-looking beasts, with 
bodies a third of an inch long, monsters, the Culex damnabilis of 
Eae, with proboscis infernali veneno inunita. I foresaw that we 
should have opportunities enough to study the natural history of 
these blood-thirsty creatures to our heart's discontent." 

About a month later he writes when searching for eggs, 
properly identified : 

" Doubtless the proper thing to have done would have been to 
lie down and watch the birds on to their nests; but to become tlie 
nucleus of a vast nebula of mosquitoes is so tormenting to the 
nerves, that we soon came to the conclusion that the birds had not 
begun to breed, and that it was no use martyrising ourselves to find 
their eggs. The mosquitoes were simply a plague. Our hats were 
covered with them; they swarmed upon our veils; they lined with 
a fringe the branches of the dwarf birches and willows; they cov- 
ered the tundra with a mist." 



150 THE WORLD OF LIFE 

But this was quite at the beginning of the season, and he 
adds: 

" We were told that this pest of mosquitoes was nothing as yet 
to what it would become later. ' Wait a while/ said our Job's 
comforter, ' and you will not be able to see each other at twenty 







"^mmi 



Fig. 16. — Messrs. Seebohm and Harvie-Brown watching Grey Plover 

through a Cloud of Mosquitoes. 

paces distance; you will not be able to aim with your gun, for the 
moment you raise your barrel half-a-dozen regiments of mosquitoes 
will rise between you and the sight.' '' 

And Mr. Seebohm described how he Avas protected by india- 
rabber boots and cavalrv 2:auntlets, and a carefully constructed 
cage over his head, without which he never dare go out on 
the tundra (see Fig. 15). 

Xow this Arctic country, beyond the limit of forests and 
stretching to the polar ocean, ^vhich is buried for eight or nine 
months under six feet thick of snow^, is yet, during its short 
summer, a very paradise for birds of all kinds, which flock to 
it from all over Europe and Central Asia in order to breed 
and to rear their young; and it is very largely, and for many 
species almost exclusively, this very abundance of mosquitoes 
and their larvae that is the chief attraction. In Mr. Seebohm's 
works, already quoted, and in his fine volume on the Geo- 



CASES OF ADAPTATiOxX 151 

graphical Distribution of the Plovers and allied birds, he gives 
a most graphic account of this country and of the birds flock- 
ing to it, which is worth quoting, as few people have any ade- 
quate idea of what the greater part of the iirctic regions really 
are in summer. After describing its extent and boundaries, 
he says: 

" I have called this district a paradise, and so it is for two 
or three months of the year. Nowhere else in the whole world can 
you find such an abundance of animal and vegetable life, brilliant 
flowers, birds both of gay plumage and melodious of song, where 
perpetual day smiles on sea and river and lake. For eight months 
or more (according to the latitude) every trace of vegetable life is 
completely hidden under a thick blanket which absolutely covers 
every plant and bush. Far as the eye can reach, in every direction 
nothing is to be seen but an interminable, undulating plain of white 
snow." 

Then after describing the few animals that live there even 
during the wunter, and the strange phenomenon in May of 
continuous day and almost perpetual sunshine, at midday hot 
enough to blister the skin, yet still apparently in mid-winter 
so far as the snow is concerned, he goes on to describe what 
there takes place: 

" The disc of snow surrounding the North Pole at the end of 
May extends for about two thousand miles in every direction where 
land exists, and is melting away on its circumference at the rate 
of about four miles an hour, and as it takes a week or more to melt, 
it is in process of being melted for a belt of several hundred miles 
wide round the circumference. This belt is crowded with migratoiv 
birds eager to push forwards to their breeding grounds — hurrying 
on over the melting snow so long as the south wind makes bare 
places soft enough to feed on, but perpetually being driven back 
by the north wind, which locks up their food in its ice-chest. 
. . . In watching the sudden arrival of summer on the Arctic 
circle, both in the valley of the Petchora, in East Eussia, and in 
the valley of the Yenesay, in Central Siberia, I was impressed with 
the fact that the influence of the sun was nearly nothing, while 



152 



THE WOKLD OF LIFE 



that of the south wind was almost everything. The great annual 
battle between summer and winter in these regions is the one event 
of the year: it only lasts a fortnight, during which a cold winter 
is transformed into a hot sunmier." 

He then gives a most interesting account of the breaking up 
of the ice on the great north-flowing rivers till they become 
roaring floods of muddy water, crowded with lumps of melted 
ice of all shapes and sizes. On the 20th May he had just 
crossed the Petchora to Ust-Zylma, over ice which was already 
cracking. 

" It was past midnight, and at any moment the crash might 
come. Cracks running for miles, with a noise like distant thunder, 




Fig. 17. — loe Breaking up on the 
Petchora River. 



warned us that a mighty power was all but upon us, a force which 
seemed to impress the mind with a greater sense of power than 
even the crushing weight of water at Niagara, a force which breaks 
up the ice more than a mile wide, at least tliree feet thick, and 
weighted with another three feet of snow, at tlie rate of a hundred 



CASES OF ADAPTATIO]^ 



153 



miles in twenty-four hours. . . . We slept for a couple of 
hours, when, looking out of the window, we found that the crash 
had come; the mighty river, Petchora, was a field of pack-ice and 
ice-floes marching past towards the sea at the rate of six miles an 
hour. We ran out on to the banks to find half the inliabitants of 
Ust-Zylma watching the impressive scene.'' 

A week later he writes : 

" Winter is finally vanquished for the year, and the fragments of 
his beaten army are compelled to retreat to the triumphant music 




Fig. 18. — Midsummer on the Tundra, at the Mouth of the Petchora River. 

of thousands of song-birds, amidst the waving of green leaves and 
the illumination of gay flowers of every hue. The transformation 
is perfect. In a fortnight the endless waves of monotonous white 
snow have vanished, and between the northern limit of forest growtli 
and the shores of the Polar basin smiles a fairy-land, full of the 
most delightful little lakes and tarns, where phalaropes swim about 
amongst ducks and geese and swans, and upon whose margins stints 
and sandpipers trip over the moss and the stranded pond-weeds, 
feeding upon the larvae of mosquitoes, or on the fermenting frozen 
fruit of last year's autumn. 



154 



THE WORLD OF LIFE 



" It is incredible how rapidly the transformation is completed. 
Twelve hours after the snow had melted the wood-anemone was in 
flower, and twenty-four hours after the yellow flowers of the marsh- 
marigold opened. In a short time the country looked like an 
English garden run wild. On the Arctic Circle wild onions, wild 
rhubarb, pansies, Jacob's ladder, purple anemones, dwarf roses, and 
a hundred other flowers made the country quite gay ; whilst on the 
tundras wild-fruits of various kinds — crowberry, cranberry, cloud- 
berry, arctic strawberry — were blended with reindeer-moss and 




Fig. 19. — Sudden Arrival of Birds in the Arctic Regions at the End of May. 

other lichens, together with the most characteristic flowers of an 
Alpine flora — gentians, saxifrages, forget-me-nots, pinks, monks- 
hoods (both blue and yellow), and sheets of the Silene acauUs, 
with its deep-red flowers. The Alpine rhododendron was replaced 
by a somewhat similar shrub. Ledum palustre; but the flora, on 
the whole, was like that of the Engadine brought down to the level 
of the sea. 

" Although the first rush of migratory birds across the Arctic 
Circle was almost bewildering, every piece of open water and every 
patch of bare ground swarming with them, a new species on an 
average arriving every two hours for several days, the period of 



CASES OF ADAPTATION 155 

migration lasted more than a month. A^ery little migration was 
observable till the last week in May, but during the next fortnight 
the migration was prodigious. In additions to enormous numbers 
of passerine birds, countless flocks of geese, swans, and ducks ar- 
rived, together with a great many gulls, terns, and birds of prey. 
During the next fortnight, from the 5th to the 19th of June, fresh 
species of passerine birds continued to arrive, and the main migra- 
tion of the great plover family took place." 

One of the objects of Mr. Seebohm's journey to the Arctic 
regions was to obtain authentic eggs and nests of the grey 
plover. He found several, after long search. They were all 
situated in depressions on a slight ridge among black bog-lakes, 
and each had three or four eggs. The charming little i)icture 
on the next page shows both nest, eggs, and young birds. 

In order to ascertain approximately how many species of 
birds visit the Arctic regions in the summer breeding season, 
I have made rough lists of all those enumerated by Mr. 
Seebohm in his two books, Siberia in Europe and Siberia in 
Asia, and find that they amount to 160 species. This is very 
nearly equal to the whole number of resident and migratory 
birds which breed in our own country (about ISO) ; but they 
cannot be more than a portion of the species that actually 
migrate to the Arctic lands, as they were the result of two 
visits only of about a couple of months each, and only two very 
limited areas were explored. My friend, Mr. II. E. Dresser, 
who also knows these regions personally and has made a special 
study of their birds, has been so good as to make an enumera- 
tion of all the birds known to breed in the Arctic regions 
of Europe and Asia, and he finds it to be land birds 81) species, 
waders and aquatics 84 species, equal to 173 in alL Consider- 
ing how vast is the extent of the country, and how few ornithol- 
ogists visit it, we may put the total number at at least ISO, 
and possibly even 200 species. 

The great accumulation of bird-life is, however, vividly pic- 
tured by Mr. Seebohm, and it is clear from all that he says — 
as well as bv what he does not sav — that the vast hordes of 



156 



THE WORLD OF LIFE 



mosquitoes must be the chief support of the innumerable mil- 
lions of young birds which have to be fed here, both passerine 
and Avading birds. Of the former more than eighty species 
are named, including seven buntings, four tits, two grosbeaks, 




Fig. 20. — Grey Plover's Nest and Young {8quatarola helvetica). 



six pipits, eleven warblers, five wagtails, two sparrows, three 
woodpeckers, the beautiful Avaxwing, and a host of others, 
many of which are among our common birds. What a delight 
to them all must be this mish northward into a land of per- 
petual daylight, swarming with the most nutritious food, fruits 
and berries for the parents, inexhaustible clouds of mosquitoes 



CASES OF ADAPTATION 157 

— which Mr. Seebohm tells us are an especially large kind 
with bodies a third of an inch long — and the equal myriads 
of their larvse in every little pond or water-hole, as well as 
quantities of larger worms and larva'. The extreme discom- 
forts as well as the cost of a journey to these far northern 
lands are so great that very few bird- or insect-collectors vi>ir 
them, and it is not easy to obtain direct and accurate obser- 
vations as to the actual part played by the myriad swarms of 
mosquitoes in attracting birds from almost every part of tlio 
northern hemisphere to go and breed there. Mr. H. 3^]. 
Dresser, who has made a special study of Palnearctic birds and 
their eggs, has, however, obtained for me some very interesting 
information. He writes: 



" Colonel Feilden tells me that the young of the knot are fed 
chiefly on the larvae of mosquitoes." 



He has also sent me a copy of the following interesting letter 
from an American ornithological correspondent, Mr. E. T. 
Seton : — 

" In reply to your recent favour I beg to say, that, in my 
forthcoming book on a canoe journey of 2000 miles which I made 
to the Arctic regions in 1907, I am setting forth at great length the 
numbers, virulence, and distribution of the mosquitoes, together 
with observations on those creatures which are immune from their 
attacks. ... I should say that the night-hawk (Chordeiles 
virginianus) is the most active enemy of this insect, feeding on it 
during the whole season. On one occasion T took over 100 
mosquitoes from the throat of one of these night-hawks, that was 
carrying them home to feed its young. Many similar observations 
have been recorded. Next in importance would come the broad- 
billed flycatchers of the American group Tyrannidae, and the more 
abundant though smaller species of the Mniotiltidse. All of these 
I have seen feeding on the adult mosquitoes. Doubtless all of our 
thrushes do the same, although I do not recall any positive records. 
We are very safe, I take it, in cataloguing all of our small birds 
as enemies of the mosquitoes in the adult form. The various 
small wading birds, and the small ducks and grebes, are believed 



158 THE WORLD OF LIFE 

to prey on the larval mosquitoes ; but doubtless it is the insects and 
small fish that are to be credited with the principal destruction in 
this stage." 

From his personal observations Mr. Dresser says: 

" I believe that most of the waders feed their young on them 
(mosquitoes) in the high north. In north Finland and Lapland 
I found the small birds (warblers, swallows, etc.) feeding on 
mosquitoes, and the snow bunting fed its young on them." 

There is, therefore, a concensus of evidence as to the pre- 
eminent attraction afforded by these insects to almost all birds 
which breed in the Arctic regions. 

The beautiful view on the opposite page gives us an idea 
of the appearance of the upland tundra along the shores of 
the Arctic Ocean. Here the southern slopes of the low hills 
are the first to be free from snow, and afford an abundant 
supply of last year's berries to the earliest migrants, as well 
as a variety of animal food for aquatic birds on the adjacent 
sea-shores in favourable situations. 

The combined physical and emotional enjoyment in this 
birds' paradise, during the whole of the Arctic summer, for 
so large a number of species of birds and in such enormous 
multitudes, is probably unequalled in any other part of the 
world; and we have the satisfaction of knowing that it is 
perhaps the only example of Nature's short-lived but annual 
pleasure-gardens which will not be destroyed or rendered 
hideous by the destructiveness and greed of civilised man. 
When much of the beauty and luxuriance of nature has been 
banished from milder regions, these inhospitable Arctic lands 
will long remain in their wild luxuriance of summer beauty, 
where those who trulv love nature wdll be able to witness one 
of the most wonderful illustrations of the mvriad forms and 
complex ada23tations which the world of life presents to us. 

It is a significant feature of this adaptation, that of all 
the higgler forms of life birds are the most completely pro- 
tected from the blood-sucking and iiTitation of mosquitoes. 



CASES OF ADAPTATIO]S[ 



159 



Every imrt of the body is protected either with a dense mass 
of phimage, or by a homy integument on the bill and feet, 
so that they are probably quite undisturbed while enjoying 
the super-abundant feast nature has spread for them in those 
remote and usually repellent lands. We may conclude, there- 
fore, that it is to the two special features of these Arctic 




Fig. 21.— The Higher Tundra. 
Stanavialachta at mouth of the Petchora River (N. Lat. 69°), 

tundras — their abundant berries preserved during the winter 
in a natural ice-house, and the myriad clouds of mosquitoes 
and their larvge — that we owe the very existence of a consid- 
erable proportion of the bird-life in the northern hemisphere. 



The Origin of Bird-migration 

These vast Arctic plains even in Tertiary times when 
climates were milder, would, owing to the long winter nights, 
have always been snow-covered during several months in winter 
although its melting might have been earlier and the sunnner 
somewhat longer ; there can be little doubt that the short sum- 



160 THE WORLD OF LIFE 

mer with its perpetual sunshine was equally favourable to the 
production of a super-abundance of vegetable and insect food 
very similar to what now exists there, and in this fact, we 
find a very complete explanation of how bird-migration came 
about. Abundance of food suitable for both parents and 
young at the season of breeding, would inevitably attract birds 
of all kinds from more southern lands, especially as the whole 
area would necessarily have no permanent residents or very 
few, but would, each recurring season, be an altogether new 
and unoccupied but most fertile country, to be reached, from 
any part of the north temperate lands, by merely following 
up the melting snow. And as, a few months later, the myriads 
of young birds in addition to their parents were driven south 
by the oncoming of the cold and darkness, they would find 
it necessary to travel farther and farther southward, and would 
again find their way north when the proper season arrived. 
There would always be a considerable niunber of the old and 
experienced birds to show the way; and as, with increasing 
severity of the seasons, the area of the snow-covered plains 
would extend, and their capacity for feeding both old and 
young would be increased ; there would at last be brought about 
that marv^ellous rush of the migrating flocks which Mr. 
Seebohm has so vividly described. 

Before quitting the subject of migration, on which Mr. 
Seebohm's observations throw so much light, I will shortly 
describe the most wonderful exhibition of migration-phenom- 
ena in the world — that of the small island of Heligoland, 
40 miles off the mouth of the Elbe in about the same lati- 
tude as Scarborough. Most of the migratory birds from 
Scandinavia and xlrtic Europe pass along the coasts of the 
German Ocean, and the lighthouse on Heligoland serves as 
a guide, and the island itself as a resting-place during bad 
weather. Mr. Seebohm's account of what he witnessed in 
the island, during nearly a month spent there in September 
to October 1875 (in chapter xx. of his Siberia in Euroj)e) 
is most interesting; and I refer to it here chiefly for the 



OASES OF ADAPTATION 161 

sake of iDointing out a very important error as to the cause 
of a very singular fact recorded there, by Herr Gatke, who 
for fifty years, observed and registered the migrations both 
in spring and autumn, with great accuracy, and formed a 
collection of birds there, perhaps more extensive than could 
be made at any other station in Europe. The fact observed 
was, that, during the autumn migration, as regards many 
of the most abundant species, the young birds of the year, 
that is, those that had been hatched in the far north in the 
preceding June or July, and who w^ere, therefore, only about 
three or four months old, arrived in Heligoland earliest and 
alone, the parent birds appearing a week or two later. This 
is the fact. It has been observed on Heligoland for half a 
century; every resident on the island knows it, and ]\Ir. 
Seebohm declares that there can be no doubt whatever about 
it. The inference from this fact (dravni by Herr Gatke and 
all the Heligolanders, and apparently accepted by almost all 
European ornithologists) is, that these young birds start on 
their migration alone, and before their parents, and this not 
rarely or accidentally but every year — and they believe also 
that this is a fact, one of the most mysterious of the facts 
of migration. Neither Mr. Seebohm nor Professor Lloyd 
Morgan (in his Habit and Instinct) express any doubts about 
the inference any more than about the fact. Yet the two 
things are totally distinct ; and while I also admit the fact 
observed, I totally reject the inference (assumed to be also 
a fact) as being absolutely without any direct evidence sup- 
porting it. I do not think any English observer has stated 
that the young of our summer migrants all gather together 
in autumn and leave the country before the old birds ; the 
American observers state that their migrating birds do not 
do so; while many facts observed at Heligoland show that 
no such inference is required to explain the admitted fact. 
Let us see what these additional facts are. 

The enormous rushes of mic^ratorv birds which rest at 
Heligoland always occur at night, and are very intermittent. 



162 



THE WORLD OF LIFE 



They usuallj take place on dark nights, sometimes in mil- 
lions; at other times, a week will sometimes pass with only 
a few stragglers. Of one such pitch-dark night Mr. Seebohm 



writes : 




Fig. 22.— The Light- 
house at Heligoland on a 
Migration Night. 



" Arrived at the lighthouse, an intensely interesting scene pre- 
sented itself. The whole of the zone of light within range of the 
mirrors was alive with the birds coming and going. Nothing else 
was visible in the darkness of the night, but the lanthorn of the 
lighthouse vignetted in a drifting sea of birds. From the darkness 
in the east, clouds of birds were continually emerging in an unin- 
terrupted stream ; a few swerved from their course, fluttered for a 
moment as if dazzled by the light, and then gradually vanished 
with the rest in the western gloom. ... I should be afraid to 
hazard a guess as to the hundreds of thousands that must have 
passed in a couple of hours ; but the stray birds that the lighthouse- 
man succeeded in capturing amounted to nearly 300." 

He also tells us that 15,000 sky-larks have been caught 
on Helifi^oland in one nio-ht ; and all aiiTee that the count- 



CASES OF ADAPTATIOjST 163 

less myriads that are seen passing over Heligoland are but 
a minute fraction of those that really pass, high up and quite 
out of sight. This is shown by the fact, that if, on a dark 
night, it suddenly clears and the moon comes out, the swarms 
of birds immediately cease. Another fact is, that, on what 
the islanders call '' good nights,'^ the birds that come to rest 
seem to drop down suddenly out of the sky. One other fact 
is mentioned by Mr. Seebohm. It is that every year the reg- 
ular migration season is preceded by a week or two, during 
which a few stragglers appear ; and these are all old birds 
and many of them slightly crippled, or partially moulted, or 
without some of their toes, or onlv half a tail, or some other 
defect. These are supposed to be mostly unmated birds or 
those whose young have been destroyed. It is also supposed 
that, during favourable weather (for the birds) migration goes 
on continuously during the season of about six weeks, though 
for the most part invisible at Heligoland, but often audible 
when quite invisible. 

Xow, the fact of the young birds only appearing on Heligo- 
land for the first week or so of the season of each species is 
easily explicable. Rem.embering that the autumnal migration 
includes most of the parent birds and such of their broods as 
have sur^dved, it is probable that the latter will form at least 
half or, more often, two-thirds of each migrating flock. But 
the young birds, not having yet acquired the full strength 
of the adults, and having had little, if any experience, in 
long and continuous flights, a considerable proportion of them 
on the occasion of their first long flight over the sea, on see- 
ing the lighthouse and knowing already that lights imply land 
and food-crops below them, and being also much fatigued, will 
simply drop down to rest just as they are described as do- 
ing. The old birds and the stronger young ones, however, 
pass high over head, till they reach the north coast of Hol- 
land, or, in some cases, pass over to our eastern coasts. We 
must also remember that the loncrer the birds are in mak- 
ing the journey overland, the more young birds are lost by 



164 THE WORLD OF LIFE 

the attacks of birds-of-prey and other enemies. Hence the 
earliest flocks will have a larger proportion of young birds than 
the later ones. The earlier flocks also, being less pressed for 
time will be able to choose fine weather for the crossing, and 
thus it will be only the young and quickly-fatigued birds that 
will probably fly low and come dow^n to rest. Later on every 
recurrence of bad weather will drive down old and young alike 
for temporary shelter and rest. Thus all the facts are ex- 
plained without having recourse to the wildly improbable 
hypothesis of flocks of immature birds migrating over land 
and sea quite alone, and a week in advance of their parents 
or guides. 

What this World-wide Adaptation teaches us 

This co-adaptation of two of the highest and most marvel- 
lous developments of the vast world of life — birds and in- 
sects — an adaptation which in various forms pervades all 
their manifestations upon the earth, from the snow^-wastes of 
the tundra to the glorious equatorial forests; and the further 
co-adaptation of both, with the vegetation amid w'hich they 
have developed, suggest some very important considerations. 

As we might expect, both birds and insects are comparatively 
rare in a fossil state, but there are suflicient indications that 
the latter were first developed. A considerable number have 
been found in the Coal Measures, especially numerous cock- 
roaches. Ancestral forms of ^N^europtera and Hemiptera allied 
to our may-flies and dragon-flies, bugs and aphides, are found 
in Devonian and Carboniferous rocks. The more his^hlv 
organised insects with a complete metamorphosis, come later; 
beetles, dragon-flies, and bugs (Hemiptera) are rather common 
in Lias beds, and here, for the first time, we meet with a 
true ancestral bird with perfectly developed wings and 
feathers, and with toothed jaw^s, the celebrated Archseopteryx. 
Diptera (flies) are also found here, as ^vell as a wasp, some- 
what doubtfully identified ; while the most highly developed 
of all insects in structure and metamorphosis, as well as in 



CASES OF ADAPTATION" 16^ 



o 



size and beauty, the Lepidoptera, are first in Tertiary beds, 
at a time when birds allied to living forms also first appeared. 
This general parallelism of development seems clearly to 
indicate that birds, in the full and varied perfection in which 
we now find them, are dependent on a correspondingly wide- 
spread development of insects ; and more especially of those 
higher orders of insects, whose exceedingly diverse stages of 
larva, pupa, and perfect insect, afforded the special food for 
immature and full-grown birds respectively. We can see how 
the omnipresence of insects adapted to feed on every kind of 
vegetable food, as well as on all kinds of animal refuse, has 
afforded sustenance to the various kinds of small mammalia, 
reptiles, and birds, which have successively become specialised 
to capture and feed on them. The early birds with toothed 
jaws were able to feed upon the cockroaches and ancestral 
iVTeuroptera and beetles of the same period. As these early, 
birds became more numerous, so they became successively 
specialised to feed upon particular kinds of insects or their 
larvae, however completely these might seem to be concealed 
or protected. Thus were gradually formed the true fly- 
catchers (Muscicapidge) and the totally distinct American fly- 
catchers or tyrant birds (Tyrannidse), which capture all kinds 
of insects on the wing; the swallows, and the very distinct 
swifts, so specialised as almost to live in the air, and to feed 
on this kind of food exclusively; the goatsuckers, which 
capture night-flying insects; the curious little nuthatches and 
creepers which hunt over trees for small beetles concealed in 
crevices of the bark; while the marvellously specialised wood- 
peckers discover the larger grubs or caterpillars which burrow 
deeply into the wood of trees, and dig down to them with 
their wonderfully constructed hammer-and-chisel-like head 
and bill, and then pull them out on the tip of their extensile 
barbed tongue. In the tropics many distinct families of birds 
have been developed to grapple with the larger and more 
varied insect forms of those countries, so that it mav be 
safely concluded that no group of the vast assemblage of in- 



166 THE WORLD OF LIFE 

sects but what has its more or less dangerous enemies among 
the birds. Even the great rapacious birds, the hawks, buz- 
zards, and owls, when their special food, the smaller mammals 
and birds, fails them, will capture almost every kind of 
ground-feeding insects; while the enormous tribes which feed 
largely on frnits and seeds often make up for its deficiency 
by capturing such insects as are available. 

One of the clearest deductions from these facts is, that the 
great variety of the smaller birds — warblers, stonechats, tits, 
w^agtails, pipits, wrens, and larks — owes its origin to the 
continuous specialisation throughout the ages of new forms of 
birds adapted to take advantage of every fresh development 
of the insect tribes as they successively came into existence. 
As Darwin repeatedly impresses upon us, excessive powers of 
multiplication with ever-present variations, lead to the almost 
instant occupation of every vacant place in the economy of 
nature, by some creature best fitted to take advantage of it. 
Every slight difference in the shape or size of bill, feet, toes, 
wing, or tail, or of colour of the various parts, or of supe- 
rior acuteness in anv of the senses, such as we can see in the 
different allied species of these birds, has been sufficient to 
secure the possession of some one of these vacant places ; and 
when this first partial adaptation has been rendered more and 
more perfect by the survival in each successive generation of 
those individuals best fitted for the exact conditions of the 
new environment, a position is reached which becomes at any 
future time a secure starting-point for further modification, 
either in the same or in any slightly diverging line, so as to 
be again fitted to occupy some other vacant place which may 
have arisen through the slightest changes either in the inor- 
ganic or the organic environment. 

So long as we limit ourselves to a consideration of the mode 
in which any existing species has been produced, by the 
adaptive modification of some other pre-existing closely allied 
species, by means of the known facts of universal variation 
and of the constant survival of the best adapted, there is no 



CASES OF ADAPTATION 167 

difficulty whatever in accepting the " origin of species " from 
other species as a demonstrated fact ; and this alone was the 
hitherto insoluble problem Avhich Darwin first succeeded in 
solving. It is only in the extension of the process to isolated 
groups such as the whales, the elephants, the serpents, or the 
mammalia; or by enquiring how special organs, such as horns, 
teeth, ears, or eyes, could have begun their process of develop- 
ment, that difficulties appear, many of which seem, to some 
biologists, to be insuperable. But many of these difficult 
problems have been solved by more complete knowledge ; while 
others have been rendered easy by the discovery of inter- 
mediate stages either through the investigations of embryolo- 
gists, or of palaeontologists, so that many of the greatest diffi- 
culties of Darwin's early opponents have quite disappeared. 
Some of these recent explanations have been referred to al- 
ready, and many others are briefly described in my Darwin- 
ism. In that work also I have given so many illustrations 
of the way in which natural selection has worked, that it will 
be needless for me to go into further details here. I will, 
therefore, now proceed to an exposition of some problems of 
a more general nature, which involve difficulties and sugges- 
tions beyond the scope of Dar^vin's work, and which, I think, 
have not been sufficiently considered by later writers on evolu- 
tion. 



CHAPTER IX 

THE IMPORTANCE OF EECOGNITION-MAKKS FOR EVOLUTION 

The great problem of the exact causes of the infinitely varied 
colours and markings of the different species of the higher 
animals, is now gradually receiving an adequate amount of 
attention, and in consequence an almost complete solution. 
In the Origin of Species Darwin dealt with only one branch, 
of the subject — coloration for concealment, and that only in- 
cidentally ; but he at once accepted, and with enthusiasm, 
Bates's explanation of the beautiful phenomena of mimicry 
among insects, and also that of warning colours in the in- 
edible caterpillars, first suggested by myself. 

The whole subject, especially that of mimicry, is now so 
largely developed as to require many volumes for its adequate 
exposition ; and I have myself given a summary of the more 
interesting facts in my Darwinism: I shall therefore deal very 
briefly with it here, with the one exception of that form of 
it which I have named " recognition marks." These, though 
the last to be generally accepted have received the least at- 
. tent ion ; but, after many years' consideration of the whole 
problem of evolution I have come to the conclusion that, of 
all the causes of distinctive marking (among the higher ani- 
mals at all events), the need for easy recognition under the 
varied conditions of their existence is for most animals the 
most important. It is, however, on account of their being 
in most cases absolutely essential as a factor in the evolution 
of new species that I here devote the larger part of this chapter 
to their consideration. 

168 



KECOGA^ITIO^^ -MARKS 169 

Coloration for Concealment and for Visibility 

Colour and markings for concealment pervade all nature. 
The hare on its form, the snipe in its covert, the vast major- 
ity of birds while sitting on their nests, the sand-coloured des- 
ert animals, and the prevalence of green colours in the in- 
habitants of tropical forests, are a few of the best-known ex- 
amples. The uses of such colours in order to protect the 
Herbivora from enemies, or to conceal those which devour 
other animals from their prey was at once acknowledged, and 
it was seen how, with variability of colour as a constant fact, 
survival of the fittest might soon bring about the beautiful 
harmony of coloration we everywhere find to prevail. But it 
was also undeniable that there were almost equal numbers 
of animals of all classes and sizes, in which colours and mark- 
ings occurred which could not by any possibility be interpreted 
as protective, because they seemed to render the creature 
glaringly conspicuous. Some of these, which w^ere most prev- 
alent among insects, were soon explained as " warning 
colours,' ' because they were exhibited by species which were 
either so nauseous as to be inedible by most insect-eaters ; or 
were armed wdth stings which might cause great pain or even 
loss of life to an enemy which attacked them. When it was 
found that many other groups of insects which did not pos- 
sess these protective qualities, yet acquired the same colours 
and often the same form ; and when my fellow-traveller on 
the Amazon, II. W. Bates, showed how this peculiar kind of 
^^ mimicry " was beautifully explained on the Danvinian 
hypothesis, not only w^as the theory itself greatly strengthened 
but a whole host of curious and beautiful colour-phenomena 
in Xature, hitherto unnoticed, were seen to come under some 
form of the same general principle. As one rather extreme ex- 
ample of mimicry I give the figures of a black wasp with white- 
banded wings, which is closely imitated by a heteromcrous 
beetle. These I captured myself in the forests of Borneo, fly- 
ing together near the ground. They are of nearly the same 



170 THE WOKLD OF LIFE 

size. The wing-coverts (elytra) of the beetle are reduced to 
pointed scales, allowing the true wings to be always extended. 
This is most unusual in beetles, as is the white band across 
the wings in this order of insects (Fig. 23). This strange 
and most unusual modification of an inoffensive insect, so 
as closely to resemble one of another order which is protected 
by a dangerous sting, can be explained in no other way than 
through the advantage derived by the harmless beetle by be- 
ing mistaken for the wasp. Of course, this change is the 
result of a very long series of slight modifications of the beetle, 
each bringing it a little nearer to the wasp, a series extend- 
ing probably through thousands or even millions of genera- 
tions.^ 

Becogniiion-Marlcs 

But though the subject of '^ mimicry " involves problems 
of extreme complexity and interest, and has therefore at- 
tracted the attention of numerous students, yet it is almost 
entirely confined to the insect world, and, taken as a whole, 
is not nearly so important a factor in the development of the 
great Avorld of life as the class of " recognition "-colours of 
which I will now give a short account. 

My attention was first directed to this subject during my 
visit to south Celebes in 1856-57, where, during about six 
months' collecting, I obtained the unusual number of fifteen 
different birds of prey, of which the majority were of the 
hawk sub-family. While skinning and preserving these birds, 
and after my return home, wdiile determining the species, I 
could not help observing in many of them the varied and 

1 Other cases are given in my Darwinism ; but those who wish to under- 
stand the whole problem and what an important part it plays in nature 
should read Professor Poulton's elaborate papers in the Transactions of 
the Entomological Society of London for the years 1902 and 1908, together 
with those of Dr. F. A. Dixey and other writers. There is also a very good 
article by Mr. E,. Shelford, on mimetic insects from Borneo, and as these 
are illusttated by coloured plates and deal with cases of the same nature as 
the one here given, they are very instructive. (See Proceedings of the 
Zoological Society of London, Nov. 4, 1902.) 




beetle. 



i.MYCNIMIA AVICULUS. 
2.C0L0B0RH0MBUS FASCIATIPENNIS, 



Fig. 23. — Mimicry of Wasp by a Beetle. 



EECOGNITION-MAEKS 171 

beautiful markings of the tail-feathers, by means of white 
spots or bands on all the feathers except the middle pair. 
The result was that when the tail was expanded during 
flight, it was seen to be marked very conspicuously by white 
bands, sometimes across the middle of the tail, sometimes at 
the end, sometimes with one band, sometimes with two or even 
three, so that the species were easily distinguished by this one 
character. But the chief peculiarity to be noticed was, that 
these bands w^ere only seen during flight, the white markings 
being quite invisible when the birds were at rest. The impor- 
tance of this fact I did not see till many years later, when, 
in connection with other similar facts, it gave a clue to their 
meaning and purpose. 

Xow that we have learnt how rapid are the powers of in- 
crease of all animals, and the extreme severity of the process 
by which the population is kept down to a nearly fixed amount 
by the annual destruction of all the less adapted ; and further, 
when we know how all the higher animals roam about in 
search of their daily food, we are able to understand how 
vitally important it is for all such animals to be able to recog- 
nise their own species from all others without fail and at con- 
siderable distances. This is essential for several reasons. 
The young and half-grown, if they have strayed away from 
the flock or herd, need to rejoin them as soon as possible ; the 
two sexes of the same species require to know each other in 
the same way by unfailing marks whether they are approach- 
ing from behind or from the front; while the separate por- 
tions of flocks divided by the sudden attack of some enemy 
need to come together again as soon as possible. But there is 
a still more important use of these distinctive markings, since 
they are almost if not quite essential to the production of neiv 
species by adaptation to change of conditions, as will be shown 
later on. 

I first gave a somewhat full account of this class of mark- 
ings, with several characteristic illustrations, in my Darwin- 
ism, in 1889; but I had briefly treated the subject in my 



172r THE WOELD OF LIFE 

lecture on the Colours of Animals given at many places in 
the United States and Canada in 1886-87, and in England in 
1888. No doubt some of the facts had been noted by other 
writers, but I thinlv I was the first to claim for it a high place 
among the factors concerned in animal evolution. The clear- 
est and most picturesque illustration of the subject 1 have seen 
is in a very short article by Mr. E. Seton Thompson in the 
American periodical " The Auk " for October 1897, from 
which I will quote the most important passage : 

" The common jack-rabbit ^ when squatting under a sage-bush 
is simply a sage-gray lump without distinctive colour or form. Its 
colour in particular is wholly protective, and it is usually accident 
rather than sharpness of vision which betrays the creature as it 
squats. But the moment it springs it is wholly changed. It is 
diflScult to realise that this is the same animal. It bounds away 
with erect ears showing the black and white markings on their back 
and underside. The black nape is exposed. The tail is carried 
straight down, exposing its black upper part surrounded by a region 
of snowy white ; its legs and belly show clear white, and everything 
that sees it is clearly notified that this is a jach-rabhit. The coyote, 
the fox, the wolf, the badger, etc., realise that it is useless to follow ; 
the cotton-tail, the jumping rat, the fawn, the prairie dog, etc., that 
it is needless to flee; the young jack-rabbit that this is its near 
relative, and the next jack-rabbit that this may be its mate. And 
thus, though incidentally useful to other species at times, the sum 
total of all this clear labelling is vastly serviceable to the jack-rab- 
bit, and saves it much pains to escape from real or imaginary 
dangers. As soon as it squats again all the directive marks disap- 
pear, and the protective gray alone is seen. In the bird-world the 
same general rule applies. When sitting, birds are protectively 
coloured; when flying, directivelyf i 

The African antelopes offer very striking examples of 
" recognition "-marks, especially those that inhabit Central and 
South Africa, where such indications are most needed. The 
land is generally open, often quite bare, but usually with scat- 

1 This appears to be the common grey hare {Lepiis a^nericanus) . 



KECOGNITION-MAEKS 173 

tered trees and bushes ; and as these animals roam over a 
great extent of country in search of food or water, and are 
also liable to the attacks of many dangerous beasts of prey, 
their safety depends largely on their keeping together in small 
or large herds. There are nearly a hundred different kinds 
of antelopes known to inhabit Africa, the larger part of them 
being found in Central and South Africa. Almost all of these 
have very distinctive markings on a general ground-colour 
harmonising with the tint of the soil or rock. These mark- 
ings are usually confined to white patches on the head and 
face, and on the hinder parts, so as to be visible in the two 
directions that are most serviceable.-^ I have also come to 
the conclusion that the horns of these animals, though pri- 
marily developed as weapons of defence — for even the lion 
is occasionally killed by the horns of the gemsbuck — have 
been so changed in each species as to serve another purpose, 
as is so often the case in nature. Their curious modifica- 
tions of form in closely allied species, and their extreme 
diversity in the whole group, leads me to conclude that their 
actual shapes have been produced quite as much for purposes 
of recognition as for attack or defence. While moving among 
high grass or bushes, or when at rest and '^ ruminating," the 
horns would often be the only part visible at a distance ; and 
this, in a district inhabited by perhaps a dozen different species 
of these animals, would be of the greatest importance in guid- 
ing a wanderer back to his own herd, and for other purposes. 
To illustrate this I here give views of the horns or heads of 
twelve different species of antelopes all found in Central or 
South Africa, and thus often meeting in the same valley or 
veldt. To these I call the reader's special attention (Figs. 24- 
35). 

The first group of four shows two of the larger antelopes 

1 The beautiful gazelle figured in my Darwinism (p. 219) shows both 
these kinds of markings very strongly; while an examination of the numer- 
ous figures of antelopes in Wood's Natural History (or in any of the more 
recent illustrated works) aff'ords numerous examples of them. 



174 THE WORLD OF LIFE 

on the left, which, with a general likeness of form, possess 
individuality both in face-marks and in the curvature of the 
horns ; while the two gazelles on the right are still more 
distinct. The next group consists of three species of the 
genus Cobus, in w^hich the horns are each so distinct in size 
and curvature as to be easily recognisable at considerable dis- 
tances ; the fourth figure shows the horns of the gemsbuck, a 
very distinct species, not only in the body markings, but also 
in the almost perfectly straight and very long horns. The 
third group shows, at the top, the two species of kudu, the 
horns of which, though exactly alike in spiral curvature, are 
yet placed at such a different angle on the head as to be easily 
distinguishable. The two lower figures are of animals not 
closely allied, but, as one inhabits East and the other South 
Africa, their ranges probably overlap each other, or once did 
so. Here there is a somewhat similar bend in the horns, but 
their thickness and direction render them absolutely distinct 
from every point of view. 

^Now, as the antelopes are very closely allied to each other, 
both in structure and external form, it seems improbable that 
all the diversities in the horns (which are sometimes very 
great in closely allied species) should have been acquired for 
the sole purpose of fighting with each other or with an enemy. 
But as these animals all possess markings on the head and 
body which can only be interpreted as recognition-marks es- 
pecially serviceable while in motion, it seems quite natural that 
the horns should have been modified to serve the same pur- 
pose while the animals are at rest, or when their bodies are 
wholly and their faces partially concealed by the grasses or 
bushes around them. 

The essential character of directive or recognition-marks 
is strikingly shown by one of the best known of the African 
antelopes — the springbok — which in the early days of the 
Cape Colony swarmed over the whole of South Africa, even 
in the vicinity of Cape Town. Its chief feature is thus de- 
scribed in Chambers's Encyclopaedia : 





Fig. 24. 
TrageJayhus spekei. 



Fig. 25. 
Boocercus euryceros. 





Fig. 26. Fig. 27. 

Gazella granti. Gazella ualleri. 

Recognition-Marks in African Antelopes. 



KECOGNITION-MAEKS 175 

" Two curious folds of skin ascend from the root of the tail to 
near the middle of the back; they are closed when the animal is 
at rest, but when leaping or running they open out and disclose a 
large white patch, which is otherwise concealed." 

We have here a structural peculiarity leading to the pro- 
duction of a distinctive white patch on a prominent part of 
the body, which patch is concealed Avhen not required and 
when it might be dangerous, and only exhibited in the pres- 
ence of some real or imaginary danger, for the sj^ringbok is 
said to be one of the most timid and cautious of all animals. 
This curious feature is more remarkable, and more clearly a 
proof of a mark designed to he seen, than even our rabbit's 
upturned tail wdien running, wdiich has been termed the 
*^ signal Hag of danger," and in moonlight or evening twilight 
serves, on the approach of an enemy, to guide the young, or 
those farthest from home, towards the family burrow. 

Recognition-Marks in Birds 

A large number of birds also possess these two kinds of 
recognition-markings, the one to be seen when resting or feed- 
ing, the other only during flight. As good examples of these 
I give figures of the head and wings of three allied species 
of stone-curlews, inhabiting Eastern Australia, the Malay 
Archipelago, and India, respectively, whose ranges sometimes 
overlap, and which are no doubt descended from a common 
ancestor. The head of each exhibits different markiuirs, bv 
which they can be easily distingTiished while feeding on the 
ground ; while the bolder markings on the wings enable them 
to keep together during their wanderings or migrations (Figs. 
36, 37, and 38). 

Markings of this character, though varied almost infinitely, 
occur in all classes of the hioher animals, and very mucli 
in proportion as their mode of life requires them. When con- 
cealment is of more importance, then the recognition is made 
effective by differences of shape or of motions and attitudes, 



176 



THE WORLD OF LIFE 



or hy special cries, as in the cuckoo. Among the birds of 
the tropical forests, while the ground colour is often protec- 
tive, as in the green of parrots, the smaller fruit-pigeons of 




Fig. 36. — (Edicnemus grallarius (East Australian Stone-Curlew). 
This species is found all over Eastern Australia and the coasts of the Gulf of 
Carpentaria. It is distinguished from its allies by the better defined whit© 
spot on the wing and its more conspicuous markings on the breast. 




Fig. 37. — (Edicnemus magnirostris (Austro-Malayan Stone-Curlew). 
This species ranges from the Andaman Islands to the Philippines and the north 
coast of Australia. The markings of the face are almost intermediate be- 
tween those of the other two species. 

the Malay Archipelago, many of the barbets, and hosts of other 
birds, yet the different species will be almost always charac- 





Fig. 28. 
Strepsiceros kudu. 



FIG. 29. 
Strejisiceros im herb is. 





FIG. 30. 
Buhalis jacksoni. 



Fig. 31. 
JEpyceros melampus. 



Recognition-Marks in African Antelopes. 



RECOG^^ITION-MARKS 



>-^7 



177 



terised bj spots or bands, or caps of brilliant or contrasted 
colours. But as these usually break up the green body into 
irregular portions, and as flowers of equally varied hues are 
common on trees, or on the orchids and other epiphytes that 




Fig. 38. — (Edicnemus recurvirostris (Great Indian Stone-Curlew). 
This species is found all over India, and also in Ceylon and Burma. This species 
is clearly defined by the upturned bill and the compact black mark around the 
eye. 

grow upon their branches, the general effect is by no means con- 
spicuous. 

]^ow, without this principle of the necessity for external 
differences for purposes of recognition of each species by their 
own kind, and especially of the sexes by each other, this end- 
less diversity of colour and marking, when not protective, seems 
difficult to explain. The Duke of Argyll, in his interesting 
work, The Reign of Law, published six years after the Origin 
of Species, expressed this objection very forcibly. After de- 
scribing many of the wonderful forms and ornaments of the 
humming-birds, he says : 

" Mere ornament and variety of form, and these for their own 
sake, is the only principle or rule with reference to which Creative 
Power seems to have worked in these wonderful and beautiful 
birds. ... A crest of topaz is no better in the struggle for 
existence than a crest of sapphire. A frill ending in spangles of 



178 THE WORLD OF LIFE 

the emerald is no better in the battle of life than a frill ending 
in spangles of the ruby. A tail is not affected for the purpose of 
flight, whether its marginal or its central feathers are decorated 
with white. . . . Mere beauty and mere variety, for their own 
sake, are objects w^hich we ourselves seek when we can make the 
forces of nature subordinate to the attainment of them. There 
seems to be no conceivable reason why we should doubt or question 
that these are ends and aims also in the forms given to living or- 
ganisms." 

In a criticism of the Duke's book (written in 1867) I 
adduced sexual preference by the female bird as sufficiently 
explaining these varieties of plumage and colour, but I have 
since come to doubt the validity of this, except so far as the 
plumes are an indication of sexual maturity; while I see in 
the need for outward marking, whether for purposes of recog- 
nition or as preventing intercrossing between incipient species, 
a sufficient cause for all such conspicuous indications of 
specific diversity as are found perv^ading the whole vast world 
of life. It now only remains to point out how these mark- 
ings have been produced, even under conditions which some 
writers have considered must render their production for this 
purpose impossible, and therefore as constituting a valid ob- 
jection to the whole theory of recognition-marks. 

An Objection to Recognition-Marhs answered 

In a book on Darwinism and Lamarckism, the late Captain 
Hutton, a well-known Kew Zealand naturalist, objected to the 
validity of recognition-marks as a cause for the development 
of specific characters, that there are, all over the Pacific, 
numerous cases of small fruit-pigeons of the genus Ptilopus, 
which each have distinctive markings, and are almost always 
confined to one island or a small group of islands. In most 
of these cases there is no other pigeon or other bird on the 
same island for which they could possibly be mistaken. He 
then says : 




^ 
fr 




^ 



Fto. 32. 

Cohiis leche. 



Fig. 33. 

Col) us defdssd. 




FIG. 34. 

Cohus maria 




Fig. 35. 
Oryx (lazclUi. 

RECOG.MTIO.N M \HKS IX Afuua.n AXTKI.orKS. 



EECOGXITIOX-MAEKS 179 

^^ Consequently it appears certain that most of these species were 
developed singly, each in its own island. If this he the case, 
the colours which now distinguish tlic dilferent species cannot be 
recognition-marks, because there is no other species in each island 
with which they could be confounded." 

Shortly afterwards the late Dr. St. George Mivart made 
the same objection as regards the very numerous species of 
beautifully coloured, lories Avhich are found in all the islands 
around Xew Guinea and in the Western Pacific. He urijed 
that the various peculiarities of colour cannot be useful as 
recognition-marks, because the colour and markings of each 
of the 2,'enera of these birds is so very distinct from that of 
all other birds inhabiting the same island, and there is usually 
only one species in each island. This argument, looked at 
superficially, seems very strong, but it is not difficult to show^ 
that it is a complete fallacy, if we follow out in detail what 
must have occurred in each case. 

It is clear, admitting evolution (as both these writers did 
admit it), that each of the species of pigeon or lory noW' 
peculiar to an island must have originated from some parent 
species in the same or some other island; and there are only 
tw^o possible suppositions — either the species originated in is- 
land A by modification of the present form, and then migrated 
to island B, afterwards becoming extinct in A ; or it migrated 
from A to B and became modified into its present form in 
B. The latter case is by far the more probable, and as it is 
clearly that which the critics contemplated, let us see exactly 
what must have happened. 

We know as a fact that, when any species reaches an is- 
land or other new habitat for the first time, if the conditions 
are favourable, it increases with marvellous rapidity, till the 
island is fully stocked, and the supply of food at some time 
of the year begins to fail, or till some enemy — a rapacious 
bird, for instance — finds out the rich banquet, and is soon 
followed by others. The rabbit in Xew Zealand and Porto 
Santo, the sparrow in the United States, and many others, 



180 THE WORLD OF LIFE 

are examples of such rapid increase. But as soon as the is- 
land is fully stocked, a number equal, or nearly so, to the 
annual increase must die off every year, and these will inevi- 
tably be the least fitted to survive. Hence natural selection 
at once begins to act, and as the conditions, even in two 
adjacent islands, are never quite the same, and as with such 
a large population slight variations in many directions will 
be very numerous, some modification to a more perfectly 
adapted form will necessarily follow. Here comes the point 
which both critics failed to notice, that the modification of 
the species into a better-adapted one must have occurred in 
the island ; and as it is universally admitted that intercrossing 
between the incipient species and the parent stock would be a 
serious check to adaptation ; and further, that varieties of the 
higher animals prefer to mate with their like, then any varia- 
tion of colour in those better adapted will be advantageous, 
will lead to more rapid change, and will thus come to charac- 
terise the new form as distinguished from that of the less- 
adapted parental form. 

It is clear, therefore, that species which are now peculiar 
to some island or other restricted locality, even when thev 
are quite unlike anything else now living around them, must 
have become differentiated from some parent stock just in the 
same way as all other species have become differentiated. 
During all the initial stages, w^hich may have occupied scores 
or hundreds of generations, some outward sign of the struc- 
tural change that was taking place was an essential part of 
the process, as a means of checking interbreeding with the less- 
modified parental form, which might linger on till the process 
was almost completed. Now, the distinctive recognition-mark 
seems to us to have no use ; but as the original form from the 
adjacent island A may still occasionally visit or be driven to 
the island B, it would now be treated as a stranger, and thus 
prevent the better-adapted form being deteriorated by inter- 
breeding with the less-adapted immigTant. 



EECOGXITIOX-MAEKS 181 

Recognition hy Butterflies 

This case shows how easy it is to make mistakes or arrive 
at wrong conchisions, imless we take account of all the de- 
tails of a problem, and endeavour to follow out the exact proc- 
esses of nature by the help of facts known to us. I can 
say this with more confidence, because I find that I have 
myself come to a hasty conclusion, which I now see to be er- 
roneous, on one aspect of this very question ; and as it in- 
volves a problem of some importance I will here state what it 
is. I find that in all my writings on this subject I have as- 
sumed, without going into details, that the theory of ^^ recog- 
nition-marks," which so well accounts for a very widespread 
type of marking and coloration in birds and mammals, is also 
applicable to a large portion of the markings of insects, es- 
pecially in the case of butterflies. But a little consideration 
shows that there is no resemblance between the two cases. 
Young mammals and birds grow up with their parents, and 
get to know their appearance in every detail. They also 
have usually brothers and sisters growing up with them, so 
that by the time they go out into the w^orld to care for them- 
selves they are thoroughly acquainted with the difference be- 
tween themselves and other species, even those nearly allied 
to them. This complete knowledge is increased by the fact 
that they are able, through the mobility of the head and neck, 
to see almost every part of their own bodies, and thus know 
that they themselves do resemble their parents. 

But with the butterflies, and most other insects, everything 
is different. The caterpillar never knows its parent, and when 
the butterfly emerges from the pupa and takes flight, it seems 
quite impossible that, among the numerous butterflies of all 
sizes, shapes, and colours that it may immediately encounter, 
it can possibly know, h^j sight, which are of its own race. Tt 
must be remembered that from tlie position nf its eyes if 
cannot see itself except at so oblique an angle as to be al- 
most useless; and when we consider the extreme diversity of 

7 t/ 



182 THE WORLD OE LIEE 

the sexes in many butterflies this adds to the difficulty of 
supposing vision to be the 'primary means of recognition. But 
it may be a secondary means. It is well known that in some 
moths the females attract males by scores at night, and this 
can only be by scent, or something analogous to it. It is 
also known that the males of manv butterflies emit a strong 
perfume which has been traced to certain peculiarly formed 
scales on the wings. Scales, apparently of a similar nature, 
have been found in several distinct families of butterflies and 
moths, and it seems probable that the function of these is 
in all cases to produce a perfume agreeable to the other sex, 
though only in a few cases is such perfume perceptible to 
us. 

It seems probable, therefore, that the sexes of Lepidoptera 
are mutually attracted by a perfume agreeable to each other, 
but disagreeable or neutral to others of the same sex or to 
other species. Each time this attractive odour was perceived 
and the source of it traced, the visual image of the insect 
would be connected with the smell, and thus only would the 
colour and markings of the species become known and be 
distinguished from that of other species. This being the 
case, we see that the complete scaly covering of so many of 
these insects serves a double purpose. It affords the means 
of using an extended surface for the highly important scent- 
glands, which, by serving to bring together the sexes of each 
species and to prevent intercrossing, would facilitate differ- 
entiation and lead to that wonderful diversity of colour and 
marking accompanying comparatively slight differences of 
structure for which this order is so remarkable, and which are 
absolutely unequalled in the whole animal kingdom. This 
variety of colour, rendered possible by the large wing-surface 
covered with small but exquisitely organised scales, is util- 
ised for securing the safety of the perfect insect to a sufficient 
extent to provide for the continuance of the race, thus keep- 
ing up that endless variety of form and colour which is, per- 
haps, one purpose of their existence. 



KECOGNITIOX-MAliXS 183 

The first great adaptation here, as throughout nature, is 
to secure conceahnent from their most dangerous enemies, and 
this is effected by various kinds of protective, deceptive, or 
-warning coloration which in some form or other pervades the 
whole order, and forms a most fascinating subject of study. 
The protective coloration is mostly on the under sides of the 
wings of butterflies, and on the upper sides of the upper wings 
of moths, the parts respectively exposed to view when the in- 
sect is at rest. Great numbers are also deceptively coloured 
by eye-marks (ocelli), which resemble the eyes of mammals 
in such a way as to be very striking in the mingled light and 
gloom of the forest and in the general surroundings of each 
species. Large groups in all the tropical regions possess warn- 
ing colours, either very bright and well contrasted, or of sober 
browns and yellows, and accompanied by such elongated wings, 
bodies, and antennae, that the facies of the whole group as 
well as of the individual species soon become known to in- 
sect-eating creatures. 

Those which are protectively or deceptively coloui-ed on 
the exposed portions of their wings often exhibit the most 
brilliant or gaudily contrasted colours elsew^here; but in these 
cases the flight is very rapid or jerky, and the insects are so 
continually hidden among the lights and shadows of the forest, 
that few enemies can capture them. The - great exj)anse of 
the wings is itself an additional protection by diverting at- 
tention from the body ; and it has thus become possible, with- 
out endangering the continuance of the species, to allow the 
development of that marvellous display of colour, the charm 
of which can only be fully appreciated by those who have for 
long periods sought it out in the forest regions of the Amazon, 
of the Eastern Himalayas, or of the Moluccas and Xew 
Guinea — the three most productive regions in the world for 
butterflies (ajiS also for birds) of resplendent hues and in 
endless variety. 



184 THE WOKLD OF LIFE 

A new Alignment against Female Choice 

Here again we find another, and I think a very conclusive 
argument against female choice having had any part in the 
production of beautiful and varied colours in the males of 
butterflies, or probably of any insects, since it is clear that 
the attraction is through another sense than that of sight, and 
all that vision can do in this direction is to enable the in- 
\ sect to recognise, perhaps at a greater distance, the individuals 
which are thus attractive. There is much evidence to support 
this view. H. Miiller, in his Fertilisation of Flowers, states 
that odour is pre-eminent in attracting insects to flowers, and, 
next to that, general conspicuousness rather than any special 
colour or form. And, by his detailed accounts of insects 
visiting flowers, we find that almost all the commoner butter- 
flies visit a great variety of honey-bearing flowers W'ithout 
much regard to colour. Thus Argynnis papliia visited flowers 
of four different natural orders, whose flowers w^ere white or 
pale red ; the large cabbage butterflies visited seven different 
orders, including red, white, purple, yellow, or blue flowers; 
the small tortoise-shell visited an even greater range of flowers 
and colours, so that we have no reason to impute to these in- 
sects anything more than the power to recognise, after experi- 
ence, any conspicuous flowers that produce pleasant odours 
and, usually, accessible honey. 

A consideration of the whole evidence as to the purpose 
served by the excessively varied and brilliant coloration of but- 
tei^ies leads us to the conclusion that its presence is due to 
general laws of colour-development — some of which will be 
discussed in later chapters — whose action is only checked 
when such development becomes injurious. In the case of 
butterflies, the comparatively short period that elapses between 
the emergence of the female from the chrysalis and the dep- 
osition of her eggs, and the still shorter period needed for the 
special functions of the more brilliantly coloured male to- 
gether wdth his power of irregular but rapid flight, render it 



EECOGNITIOX-MAEKS 185 

possible for the colour-development to attain a degree of 
variety and beauty beyond that of all other living things. 
The larvae of Lepidoptera in their countless myriads un- 
doubtedly constitute an important factor in supporting the 
gloriously varied bird-life of the tropics, as we have seen 
that they so largely support that of our temperate ^nes. 
It is the comparatively small surplus that escapes which is 
yet ample for the development of the perfect insects in such 
abundance as to keep up an approximately equal supply of 
larva? for the next generation of birds. When this is done they 
themselves become the prey of birds, lizards, and other insect- 
eating animals. 

Some General Conclusions from Recognition-Marks 

We have thus been led by the study of colour as a means 
of recognition by birds and mammals to some very important 
general conclusions. The first is, that in both these groups, 
it has primarili/ a still more important function, that of facili- 
tating the formation of new species during the early stages 
of adaptation to changed conditions of life. Its secondary, 
but still very important use in many groups, is for easy identi- 
fication as alreadv described. That this is the true state of 
the case is rendered almost certain by the occurrence of a 
large number of species in which the markings for recognition 
are noiv unnecessary though they were of the highest impor- 
tance during the initial stages of evolution. 

Another and still more curious result of the study of this 
subject is the evidence it affords that the most varied in colour 
and markings ' of all insects — the butterflies — do not, pri- 
marily, recognise each other by sight, but by some sense 
analogous to that of smell. This seems now to be almost cer- 
tain, and it affords the explanation of what would otherwise 
be a great difficulty, how the males of polymorphic females, as 
in Papilio pammon in the East and Papilio apneas in the West, 
numerous American Pieridir and many other groups, in which 
the females are coloured as if with the purpose of being as un- 



186 



THE WOKLD OF LIFE 



like their mates as possible, are able to recognise each other. 
Intuitive knowledge or " instinct " is now given up by every 
thinker; but the proof now given that the only knoiun method 
of mutual recognition by Lepidoptera is by scent, explains the 
whole difficulty. The colours and markings of these insects 
have been produced in adaptive relation to their enemies al- 
most exclusively, and this explains the fact that the strangely 
diverse females above referred to are, probably in every case, 
either protectively coloured or mimics of distasteful forms 
in their own district. The fact that several of the Eastern 
Papilios have fully tailed females while they themselves are 
round-winged, is another indication that sight can have no 
part in leading to mutual recognition between the sexes. 

The almost universal presence of some form of recognition- 
marks in birds and mammals, no less than the proof now af- 
forded (and for the first time stated) of their entire absence in 
the Lepidoptera, affords, I think, ample justification for the 
importance I claim for them, and for the space I have devoted 
to them in the present volume. 



CHAPTER X 

THE EAETIl's SURFACE-CHANGES AS THE CONDITION AND 
MOTIVE-POWER OE ORGANIC EVOLUTION 

Having now sketched in outline the main factors on which 
organic evolution depends — heredity, variation, and rapid 
powers of increase — and having shown by a sufficient nuni- 
ber of examples that these factors are omnipresent features of 
organic life, only varying somewhat in the proportions of their 
occurrence in different species, we are now prepared to indi- 
cate the conditions under which they have acted in the produc- 
tion of those numerous changes of form and structure which we 
observe in the various forms of life. 

We have seen (in Chapter VI.) that so long as no consid- 
erable changes occur in the inorganic world, the effect pro- 
duced by the constant interaction between species and species, 
or between plants and animals, results in changes of local dis- 
tribution of the various species rather than in any important 
modification of the species themselves. And there really 
seems no reason why such changes should occur ; because when 
once complete or sufficiently complete adaptation to conditions 
is brought about, the whole of the organic world will bo in a 
state of stable equilibrium, with sufficient elasticity in all its 
parts to become adjusted to all minor periodical changes of 
climate, etc., by temporary changes in numbers, and by the 
local distribution of the sliffhtlv altered numbers. Once such 
an efpiilibrium is attained, there seems no reason why it should 
not be permanent. Xatural selection would keep up the suffi- 
cient adaptation of each species, but would not tend to change 
them. 

Geology proves that the inorganic environment — the 

187 



188 THE WORLD OF LIFE 

earth's surface — is not stable ; but that very considerable 
changes in climate, in the contour of the land surface, and 
even in the minor distribution of land and water, have con- 
tinually occurred during past ages; and that just in proportion 
to the evidence for such changes do we find that changes have 
occurred in the forms of life inhabiting every part of the 
earth. A short statement of the nature of these two groups of 
coincident and interdependent changes will therefore be useful 
here. 

The most general and most arresting facts of world-history, 
revealed by geology, are, that the superficial crust of the earth 
consists of various " rocks " (including in this term every kind 
of inorganic matter of which the crust is composed) deposited 
in more or less regular " strata " or layers, one above another ; 
that these strata are sometimes horizontal, more often inclined 
at various angles to the horizon, and even occasionally vertical; 
usually continuing at about the same angle or slope for many 
miles, but often curved or waved, or even crumpled up and 
contorted in remarkable ways. These various strata consist of 
many distinct kinds of rock — sandstones, limestones, clayey 
or slaty rocks, metamorphic or gneissic rocks ; and all of these 
give distinct evidence of having been deposited in water, both 
from mechanical texture and the arrangement of their com- 
ponent particles, and also by frequently having embedded in 
them the remains of various organisms, those that live in seas 
or lakes being by far the most abundant and varied. As an 
example of this abundance we may mention the Barton Cliffs 
on the Hampshire coast east of Christchurch, where, in a dis- 
tance of a few miles, over a thousand distinct species of the 
fossilised shells of molluscs, radiates, and other marine animals 
have been found. 

But the most suggestive fact from our present point of view 
is, that almost eveiy mountain-range on the earth presents us 
examples of such stratified rock-strata, often with abundant 
fossils of marine animals, at enormous heights above the sea- 
level. Such are found in the Alps at 8000 feet, in the Andes 



EARTH CHANGES AND EVOLUTION 189 

at 14,000 feet, and in the Himalayas at 16,000 feet elevation. 
Innumerable cases of marine fossils at lesser heights are to be 
found in every part of the world, and in rocks of very various 
geological age. But the causes that have produced these great 
changes of level are still obscure. It is certain, however, that 
such changes have been exceedingly gradual in their operation, 
and have in all probability been of the same general nature as 
those going on at the present day — such as the earthquakes 
which, at irregular intervals, occur all over the world. 

There is one very instructive mode of ascertaining the rate 
of certain changes of the earth's surface which was first pointed 
out by Mr. Alfred Tylor more than half a century ago,^ and is 
generally accepted by geologists as of great value. The sur- 
plus water of the land is carried into the sea by rivers, each 
of which has a drainage area which contains a certain number 
of square miles. By careful measurements, it is possible to 
ascertain how much water flows away every year, and also 
how much solid matter is suspended in the water, how much is 
chemically dissolved in it, and how much is pushed along its 
bed at the mouth. The sum of these three quantities gives us 
the cubic yards or cubic miles of solid matter denuded from 
the surface of each river-basin in a year; and from this amount 
we can easily calculate how much the whole surface is lowered 
each year, while some corresponding area of the adjacent sea- 
bottom, on which it is deposited, must be proportionally raised. 
These measurements have been very carefully made for a num- 
ber of large and small rivers in various parts of the world, and 
the following results have been accepted as fairly accurate by 
Sir A. Geikie : — 

The Mississippi lowers its basin 1 foot in 6000 years. 





Ganges 








2358 






Hoang-Ho 








1464 






Rhone 








1528 






Danube 








6848 






Po 








729 





1 See Phil. Mag., April 1853. 



190 THE WORLD OF LIFE 

We can easily see here that the rapidity of denudation is 
proportionate to the height and extent of the mountain-ranges 
in which the river has its sources, combined with the amount of 
the average rainfall, and the proportion of plains to uplands 
in its whole basin. The Ganges has a large proportion of low- 
land plain in its area; the Hoang-Ho has less, and therefore 
denudes more rapidly. The Danube and the Mississippi both 
drain an enormous area of lowlands where denudation is slight, 
and the rainfall of both is moderate; they therefore lower 
their basins slowly. The Po drains an enormous extent of 
snowy Alps in proportion to its whole basin, and in conse- 
quence lowers the land perhaps more rapidly than any impor- 
tant river on the globe. On the whole, we may take these 
rivers as fairly representative. Their mean rate of denuda- 
tion is very nearly one foot in three thousand years, and we 
may therefore, till more complete observations are made, take 
this as a measure of the average rate of denudation of most of 
the great continents. 

Of course, the rate of lowering will be extremely unequal, 
being at a maximum in the mountains and a minimum in 
the plains, where it may not only be nothing at all, but if 
they are flooded annually they may be raised instead of 
lowered. In the loftier mountains with numerous peaks and 
precipitous slopes the average lowering may often be ten times, 
and sometimes even a hundred times, the mean amount. In 
such districts w^e can even see and hear the process continually 
going on. Under every precipice there is a more or less ex- 
tensive mass of debris — the " screes " of our lake district ; 
and every winter, chiefly through the action of rain and frost, 
the rocks above are split off, and can be heard or seen to fall. 
Even on grassy hills after a few hours' downpour of rain, in- 
numerable trickles of muddy water course down in every di- 
rection ; while every streamlet or brook — though usually of 
water as clear as crystal — becomes a rapid torrent of mud- 
laden w^ater. It is by a consideration of these every-day phe- 
nomena in operation over every square yard of thousands of 



EAETH CHANGES AND EVOLUTIOiV 191 

square miles of surface that we are able to understaucj ami 
appreciate the tremendous power of rain and rivers, greatly 
assisted by frost, in the disintegration of rocks, which lower 
the whole surface of the land at such a rate that, if we had 
means of accurate comparison with its condition a few thou- 
sand years ago, we should see that in many places the whole 
contour and appearance of the surface was changed. 

When this mode of estimating the rate of subaerial de- 
nudation was first applied to well-known regions, geologists 
themselves were surprised at the result. Eor 1 foot in three 
thousand years is 1000 feet in three million years, a period 
which has always been considered very small in the scale of 
time indicated by geological changes. When we consider that 
the mean height of all Europe (according to a careful esti- 
mate by Sir John Murray) is a little under 1000 feet, we find, 
to our astonishment, that, at the average rate of denudation, 
the whole would be reduced almost to sea-level in the very 
short period of three million years, while all the other great 
continents would be reduced to the condition of '^ pene-plains '' 
(as the American geologists term it) in about six or eight 
million years at the utmost. It is quite certain, therefore, 
that there must be some counteracting uplifting agency, either 
constantly or intermittently at work, to explain the often-re- 
peated elevations and depressions of the surface which the 
whole structure and mechanical texture of the vast series of 
distinct geological formations with their organic remains, prove 
to have taken place. 

The exact causes of these alternate elevations and depres- 
sions, sometimes on a small, sometimes on a gigantic scale, 
have not yet been satisfactorily explained either by geologists 
or physicists. Two of the suggested causes are undoubtedly 
real ones, and must be constantly acting; but it is alleged by 
mathematical physicists that they are not adequate to produce 
the whole of the observed effects. They are both, however, ex- 
ceedingly interesting, and must be briefly outlined here. We 
require first, however, to trace out what becomes of the de- 



192 THE WORLD OF LIFE 

nuded matter that lowers the continental snrfaces at so rapid 
a rate, and is poured into the sea at various points around 
their coasts ; and this is the more necessary because recent re- 
searches on this matter have led to results as surprising as those 
of the measurement of the amount of denudation bv rivers. 

During the voyage of the Challenger round the world for 
the purpose of oceanic exploration, not only was the depth of 
the great oceans determined by numerous lines of soundings 
across them in various directions, but, by means of ingenious 
apparatus, samples of the sea-bottom w^ere brought up from all 
depths, and especially along lines at right angles to the shore 
at short distances from each other. The exact physical and 
chemical nature of all these samples was accurately determined, 
and some most curious results were brought to light. 

The earlier geologists had assumed, in the absence of direct 
evidence to the contrary, that the suspended matter poured 
into the sea by rivers was, sooner or later, by means of winds 
and waves and ocean currents, distributed over the whole of 
the ocean floors, and was gradually filling up or shallowing 
the oceans themselves. But the Challenger researches showed 
that this idea was almost as remote as possible from the truth. 
The actual facts are, that the wdiole of the land debris, with a 
few special and very minute exceptions, are being deposited on 
the sea-bottom very near the shore, comparatively speaking, 
and all but the very finest material quite close to it. Every- 
thing in the nature of gravel or sand, of which so much of the 
rocky strata consists, is laid down within a very few miles, 
only the finer muddy sediments being carried so far as from 
20 to 50 miles from land; w^hile the very finest of all, under 
the most favourable conditions, rarely extends beyond 150 and 
never exceeds 300 miles from land into the deep ocean. Mr. 
A. Agassiz also, has found that the extremely fine mud of the 
Mississippi River is never carried to a greater distance than 
100 miles from its mouth. If we take even so much as 50 
miles for the average distance to which the denuded matter is 
carried, w^e find the whole area of deposit around South 



EAKTH CHANGES AND EVOLUTION 193 

America to be 60,000 square miles. But the area of that con- 
tinent is about six million square miles, so that deposition goes 
on about a hundred times as fast as denudation ; while over 
considerable areas where the deposits are of a sand}^ rather than 
of a muddy or slaty nature, it may go on a thousand times as 
fast. This is a most important fact which does not appear 
to have been taken into full consideration by geologists even 
to-day. 

The correlative fact as to the ocean bed is, that over the 
whole of it, when more than the above-named distances from 
land, what are called " deep-sea oozes " are found. These 
are formed almost entirely by the calcareous or silicious skele- 
tons of minute organisms, together with small quantities of 
decomposed pumice and of meteoric or volcanic dust. Along 
with these in certain areas the remains of larger marine ani- 
mals are found, especially the otoliths (or ear bones) of whales 
and the teeth of sharks. And the extreme slowness of the 
deposit of these oozes is shown by the fact that it is often im- 
possible to bring up a dredging from the bottom that does not 
contain some of these bones or teeth. It seems as if much 
of the ocean bed were strewn with them ! Now, these oozes, 
so easily recognised by their component materials and their or- 
ganic remains, form no part of the upheaved crust of the earth 
on any of our continents. This is, of itself, a conclusive proof 
that oceans and continents have never changed places in the 
whole course of known geological time; for if they had done 
so (as is still maintained by many rather illogical writers) the 
epoch of submergence would be indicated by some fragments, 
at least, of the consolidated ocean ooze which must once have 
covered the whole continental area.^ 

1 For a full discussion of this question, see my Darwinism, chap, xii.; 
Island Life, chaps, vi. and x.; and Studies Scientific and Social, vol. i. 
chap. ii. In this last work the whole argument is summarised and the 
numerous converging lines of evidence pointed out. 



194 THE WORLD OF LIFE 

Thickness of the Earth's Crust 

We now have to consider a quite different set of phenomena 
which have a very important bearing on the causes which have 
produced the elevations and depressions which have occurred 
over much of the land surface of the globe. It is a universal 
fact that as we descend into the crust of the earth (in deep 
wells or mines) the temperature rises at a tolerably uniform 
rate, which is found to be on the average one degree Fahr. for 
eveiy 47% feet. This rate, if continued downwards, would 
reach the temperature of melted rock at a depth of about 20 
miles. Hot springs in non-volcanic countries furnish an ad- 
ditional proof of the high temperature of the interior. Below 
the depth above indicated there would probably be some miles 
of rock in a plastic state, while irregularities w^ould result 
from the nature of the rock, some being more easily melted than 
others. 

^ow, it has been ascertained that the various rocks of the 
crust are of less specific gravity in the solid state than when 
they are liquefied, so that the crust may be looked upon as 
actually floating upon the liquid interior, very much as the 
polar ice-sheets float upon the ocean. A curious confirmation 
of this has been given by measurements of the force of gravity, 
which show that near all great mountain masses gravity is di- 
minished, not only by the amount due to the mass of the moun- 
tain itself, but to about double that amount. This is so uni- 
versally the case that it has been concluded that the weight of 
the mountain mass is supported by a corresponding mass 
forced down into the fluid magma, and hence termed the 
^^ roots of the mountains " ; just as every lofty iceberg must 
have a mass of submerged ice about nine times as great to sup- 
port it in the water. This, of course, proves that the crust is 
flexible, and that just as any portion of it is upheaved or made 
thicker by additions above, a corresponding increase in thick- 
ness must occur below to keep it in equilibrimn. 

Thus are explained the ver^^ frequent phenomena of hori- 



EARTH CHANGES AND EVOLUTION 195 



o 



zontal strata occurring in similar beds for thousands of feet 
thick, while each successive bed must have been formed at or 
near the surface. Such are the deposits recently formed in the 
deltas of great rivers, in many of which borings have been 
made from 350 to 640 feet deep, with indications that each 
successive layer was formed near the surface, and that during 
the entire process of deposition the whole area must have been 
sinking at a very regular rate. This can best be explained 
by the weight of the matter deposited causing the slow sub- 
sidence. Exactly similar phenomena occur through the whole 
series of the geological formations to the most ancient ; in some 
cases strata eight miles in thicloiess showing proofs that the 
very lowest beds w^ere not deposited in a deep ocean, but in 
quite shallow w^ater near shore. ^ 

Now, as w-e have seen that, over many areas not far from 
shore, deposition may occur 100 or even 1000 times as fast 
as denudation, and that this same area is continuously lowered 
by the weight forcing the crust downwards, we have a real 
and efficient cause for continuous subsidence and the forma- 
tion of parallel strata of enormous thicknesses. It remains to 
account for the subsequent upheaval of these areas, their tilt- 
ing up at various angles, and in many cases their being frac- 
tured, curved, or contorted often to an enormous extent and 
in a most fantastic manner. 

Effects of a Cooling and Contracting Earth 

It is universally admitted that the earth is a cooling and 
therefore a contracting body. The cooling, however, does not 
take place by conduction from the heated interior through the 
solid crust, the temperature of which at and near the surface 
is due wholly to sun-heat, but by the escape of heated matter 
to the surface through innumerable hot or warm springs; by a 
continuous flow of heated gases from volcanic areas; and fre- 
quent outbursts of red-hot ashes or liquid lavas from vol- 

1 In chapter iii. of vol. i. of my Studies Scientific and Social I have given 
details of these phenomena on the highest geological authority. 



196 THE WORLD OF LIFE 

canoes. The springs bring up from great depths a quantity 
of matter in solution, and the whole of the above-mentioned 
agencies result not only in a very considerable loss of heat, but 
also in a very great outflow of solid matter, which, in the course 
of ages, must leave extensive cavities at various depths, and 
thus produce lines or areas of weakness which almost certainly 
determine the mode in which contraction will produce its chief 
effects. 

As the outer crust for a considerable depth has its tem- 
perature determined by solar heat, and also because the tem- 
perature at which the rocks become liquid is tolerably uni- 
form, the loss of heat, causing shrinkage of the globe as a 
whole, must occur in the liquid interior; and, as this becomes 
reduced in size, however slowly, it tends to shrink away from 
the crust. Hence the crust must readjust itself to the in- 
terior, and it can only do so by a process of crumpling up, 
owing to each successive concentric layer having a less area 
than that above it. This shrinkage has been compared with 
that of the rind of a drying-up apple. But the earth's crust 
having been for ages subject to ever-varying compressions and 
upheavals, and being formed of materials which are of un- 
equal strength and tenacity, the actual results will be exceed- 
ingly unequal, and the inequalities will be most manifested 
along or near to certain lines of weakness caused by earlier 
shrinkage due to the same cause. 

As the crust will be of greater extent than the contracted 
liquid core it has finally to rest upon, and as the chief effects 
of contraction are limited to certain directions and to com- 
paratively small areas, and if the less fractured and more rigid 
portions settle down almost undisturbed upon the contracted 
interior, then considerable areas along, or parallel to, the lines 
of weakness must be crumpled, fractured, and forced upward, 
and thus produce great elevations on the surface, though small 
in proportion to the whole dimensions of the earth. IN'ow, the 
ocean floors are enormous plains, except that they have, here 
and there, volcanic islands rising out of them. The water which 



EARTH CHANGES A:N'D EVOLUTION 197 

covers them preserves uniform temperature, whicli, at the bot- 
tom, is not much above the freezing point of sea-water. We may 
conclude, therefore, that they are very nearly stable. Pen- 
dulum experiments show that the crust below these oceans is 
more dense than the subaerial crust, due, probably, to the uni- 
form pressure and temperature they have been subject to for 
geologic periods. We may assume, therefore, that they do not 
become crumpled or distorted by the contraction of the liquid 
earth beneath them. The great plains of Eussia, mostly of 
Triassic and Jurassic age, consist of nearly horizontal strata, 
while the Alps of Central Europe are greatly upheaved and 
contorted ; and the same difference between adjacent areas is 
found in the United States, and most probably in all the great 
continents. 

Mathematical physicists have calculated the possible up- 
heavals that could be produced by a shrinking crust at prob- 
able rates of contraction, and have declared them to be too 
small to account for the elevation of the existing land- 
masses above the ocean floors, that is, for the whole differences 
of height of the land surfaces. But if, as the Rev. O. Eisher 
suggests, the oceanic basins were formed at an early stage of 
the earth's consolidation, by the separation from it of the moon 
in the way described by Sir George Darwun and accepted by 
Sir Robert Ball ; and if the whole wrinkling effect of contrac- 
tion is concentrated on a few lines or areas of weakness, al- 
ways near existing mountains ; and further, if this cause of 
elevation be supplemented by the continual subsidence of large 
areas along the margins of all the continents by the weight of 
new deposits producing a pressure on the liquid interior, which 
must result in upward pressures elsewhere, then it seems pos- 
sible that a combination of these causes may be sufficient. 

Yet another cause of elevation has recently been demon- 
strated. After many unsuccessful attempts, the actual ex- 
istence of semi-diurnal lunar tides ivithin iJic earth's interior 
has been proved; and such tides must, it is said, generate a 
vast amount of heat, culminating at tlio bi-monthly periods of 



198 



THE WORLD OF LIFE 



maximum effect. The heat thus produced would be greatest 
where the under surface of the crust was most irregular, that 
is, under the land surfaces, and especially under the ^' roots of 
mountains " projecting below the general level. Their cumu- 
lative results would, therefore, add to the upward forces pro- 
duced by contraction along lines of weakness.^ 

But whether the various forces here suggested have been 
the only forces in operation or not, the fact of the repeated 
slow elevations and depressions of the earth's surface is un- 
doubted. The most general phenomenon seems to have been 
the very slow elevation of gTcat beds of strata, deposited one 
above another along the coasts of a continental mass, or some- 
times along the shores of inland seas; immediately followed 
by a process of denudation of this surface by rain and rivers, 
which, as the elevation continued, carved it out into a complex 
series of valleys and ridges till it ceased to rise farther. The 
denudation continuing, the whole mass became worn away into 
lowland plains and valleys. Then, after a long period of 
quiescence, subsidence began, and as the land sank beneath the 
water new deposits were laid down over it. Sometimes re- 
peated elevations and depressions of small extent occurred; 
while at very long intervals there was great and long-continued 
subsidence, and, while deeply buried under newer strata, the 
older masses were subjected to intense subterranean heat and 
compression, which altered their texture, and often crumpled 
and folded them up in the strangest manner conceivable. 
Then, perhaps, a long period of elevation brought them up and 
up, till they were many thousand feet above sea-level ; and, 
when the superficial covering of newer beds had been all re- 
moved by denudation, the folded strata were themselves ex- 
posed to further denudation, and all the strange peaks and 
ravines and rushing cataracts of alpine mountains became re- 
vealed to us. 

1 This sketch of the internal structure of the earth, as affecting elevation 
and depression of its surface, is fully discussed in INIr. 0. Fisher's Physics 
of the Earth's Crust, a popular abstract of which is given in my Studies 
Scientific and Social, vol. i. chap. iii. 



EAKTH CHAKGES AND EVOLUTION I'JO 

ThuSj in alternate belts or more extended areas, our con- 
tinents have been, step by step, built up throughout the ages, 
■with repeated alternations of sea and land, of mountain and 
valley, of upland plateaus and vast inland seas or lakes, the 
indications of which can be clearly traced throughout the ages. 
And, along with these purely terrestrial changes, there have 
been cosmic changes due to the varying eccentricity of the 
earth's orbit and the precession of the equinoxes, loading to 
alternations of hot, short summers with long, cold winters, and 
the reverse; culminating at very distant intervals in warm and 
equable climates over the whole land surface of the globe ; at 
other shorter and rarer periods in more or less severe " ice- 
ages," like that in which the whole north temperate zone was 
plunged during the Pleistocene period, long after the epoch 
when man had first appeared upon the earth. ^ 

Long Persistence of the Motive Power thus caused 

It is in tliis long series of physical modifications of the 
earth's surface, accompanied by changes of climate, partly due 
to astronomical revolutions, and partly to changes in aerial 
and oceanic currents dependent on terrestrial causes, that we 
find a great motive power for the work of organic evolution, 
the mode of operation of which we now have to consider. 

Before doing so, however, I would call attention to the fact 
of the very extraordinary complexity and delicacy of the 
physical forces that have continued to act almost uniformly, 
and with no serious break of continuity, during the whole vast 
periods of geological time. These forces have always been 
curiously balanced, and have been brought into action alter- 
nately in opposite directions, so as to maintain, over a large 
portion of the globe, land surfaces of infinitely varied forms, 
which, though in a state of continuous flux, yet never reached 
a stationary condition. Everywhere the land is being low- 
ered by denudation towards the sea-level, and part by part is 

1 See my Island Life, chapters vii., viii., and ix., for a full discussion of 
the causes and effects of glacial periods. 



200 THE WOKLD OE LIFE 

always sinking below it, yet ever being renewed by elevatory 
forces, whose nature and amount we can only partially deter- 
mine. Yet these obscure forces have always acted with so 
much regularity and certainty that the long, ever-branching 
lines of plant and animal development have never been com- 
pletely severed. If, on the other hand, the earth's surface had 
ever reached a condition of permanent stability, so that both 
degrading and elevating forces had come to a standstill, then 
the world of life itself would have reached its final stage, and, 
w^anting the motive power of environmental change, would have 
remained in a state of long-continued uniformity, of which the 
geological record affords us no indication whatever. 

Readers of my book on Man's Place in the Universe will 
remember how, in chapters xi, to xiv., I described the long 
series of mechanical, physical, and chemical adjustments of 
the earth as a planet, which were absolutely essential to the 
development of life upon its surface. The curious series of 
geological changes briefly outlined in the present chapter are 
truly supplementary to those traced out in my former work. 
The conclusion I drew from those numerous cosmic adapta- 
tions was that in no other planet of the solar system were the 
conditions such as to render the development of organic life 
possible upon them — not its existence merely, which is a 
vastly different matter. That conclusion seemed to many of 
my readers, including some astronomers, geologists, and 
physicists, to be incontestable. The addition of the present 
series of adaptations, whose continuance throughout the whole 
period of world-life history is necessary as furnishing the mo- 
tive power of organic development and adaptation, not only 
increases to an enormous extent the probability against the de- 
velopment of a similar ^^ world of life," culminating in man, in 
any other known or reasonably conjectured planet, but af- 
fords, in my opinion, an exceedingly powerful argument for an 
overruling Mind, which so ordered the forces at work in the 
material universe as to render the almost infinitely improbable 



EAKTH CHANGES AND EVOLUTION 20i 

sequence of events to which I have called attention an actual 
reality. 

Terrestrial Temperature Adjustments 

Among the many wonderful adjustments in the human 
body, and in that of all the higher vertebrates, none perhaps 
is more complex, more exact, and apparently more difficult 
of attainment than those which preserve all the circulating 
fluids and internal organs at one uniform temperature, vary- 
ing onlj^ four or five degrees Fahr., although it may be ex- 
posed to temperatures varying more than a hundred degrees. 
Hardly less wonderful are those cosmical and physical adjust- 
ments, which, during many millions of years, have preserved 
the earth's surface within those restricted ranges of temper- 
ature which are compatible with an ever-increasing develop- 
ment of animal and vegetable life. 

Equally remarkable, also, is that other set of adjustments 
leading to those perpetual surface-changes of our globe which 
I have shown to be the motive power in the development of 
the marvellously varied world of life; and which has done this 
without ever once leading to the complete subsidence of any 
of the great continents during the unceasing motions of ele- 
vation and depression which have been an essential part of 
that great cosmic scheme of life-development of which I am 
now attempting an imperfect exposition. 

That the temperature of the earth's surface should have been 
kept within such narrow limits as it has been kept during the 
enormous cycles of ages that have elapsed since the Cambrian 
period of geology, is the more amazing when we consider that 
it has always been losing heat by radiation into the intensely 
cold stellar spaces ; that it has always, and still is, losing heat 
by volcanoes and hot springs to an enormous extent; and that 
these losses are only counteracted bv solar radiation and the 
conservative effect of our moisture-laden atmosphere, which 
again depends for its chief conservative effect on the enormous 



202 THE WORLD OF LIFE 

extent of our oceanic areas. That all these agencies should 
have continued to preserve such a uniformity of temperature 
that almost the whole land surface is, and has been for count- 
less ages, suitable for the continuous development of the world 
of life, is hardly to be explained without some Guiding Power 
over the cosmic forces which have brought about the result. 



1 

i 



i 



i 



CHAPTER XI 

THE PROGRESSIVE DEVELOPMEITT OF THE LIFE-WORLD^ AS 
SHOWN BY THE GEOLOGICAL RECORD 

In order to form any adequate conception of the world of 
life as a whole, of the agencies concerned in its development, 
and of its relation to man as its final outcome, we must en- 
deavour to learn something of its past history; and this can 
only be obtained by means of the fossilised remains preserved 
in the successive strata or layers of the earth's crust, briefly 
termed " the geological record." In the preceding chapter I 
have endeavoured to indicate the forces that have been at work 
in continually moulding and remoulding the earth's surface; 
and have argued that the frequent changes of the physical en- 
vironment thus produced have been the initial causes of the 
corresponding changes in the forms of organic life, owing to 
the need of adaptation to the permanently changed conditions; 
and also to the opening up of new places in the economy of 
nature, to be successively filled through that divergency of 
evolution which Darwin so strongly insisted upon as a neces- 
sary result of variation and the struggle for existence. 

But in order to appreciate the extent of the changes of the 
earth's surface during the successive periods of life-develop- 
ment, it is necessary to learn how vast, how strange, and yet 
how gradual were those changes ; how they consisted of alter- 
nate periods of not only elevation and depression, but also of 
alternations of movement and of quiescence, the latter often 
continuing for long periods, during which more and more 
complete adaptation was effected, and, perhaps in consequence 
a diminished preservation in the rocks, of the life of the period. 
Thus have occurred those numerous " breaks " in the geo- 
logical record which separate the great " eras " and " sys- 

203 



204 THE WORLD OY LIFE 

terns " of the geologist. These phenomena are admirably ex- 
plained in Professor James Geikie's attractive and well-illus- 
trated volume on '^ Earth Sculpture or the Origin of Land 
Forms," published in 1898. Here I can only attempt to 
sketch in outline the successive stages of life which are ex- 
hibited in the rocks, and point out some of their most striking 
features with the conclusions to which they lead us. 

During the latter part of the eighteenth century geologists 
were beginning to obtain some detailed knowledge of the 
earth's crust and its fossils, and arrived at a first rude di- 
vision into primitive, secondary, and tertiary formations. 
The first were supposed to represent the epoch before life ap- 
peared, and comprised such rocks as granite, basalt, and 
crystalline schists. 'Next above these came various strata of 
sandstones, limestones, and argillaceous rocks, evidently of 
aqueous origin and often containing abundant fossils of 
marine, fresh-water, or terrestrial animals and plants. The 
tertiary were clearly, of more recent origin, and contained 
shells and other remains often closely resembling those of liv- 
ing animals. It was soon found, however, that many of the 
rocks classed as " primitive " either themselves produced 
fossils, or were found overlying fossiliferous strata; and, by a 
more careful study of these during the early part of the nine- 
teenth century, the three divisions were more precisely limited 
— the first or '^ Primary,'' as containing the remains of Mol- 
lusca, Crustacea, and some strange fishes and amphibians; 
the '' Secondary," by the first appearance of reptiles of many 
strange forms ; and the ^' Tertiary," by abundance of Mam- 
malia of all the chief types now existing, with others of new 
and apparently primitive forms, or serving as connecting links 
w^ith living groups. 

It is a very remarkable fact, not sufiiciently dwelt upon in 
geological treatises, that this first grouping of the whole of 
the life-forms of the past into three great divisions, at a time 
when our knowledge of extinct animals and plants was ex- 
tremely scanty as compared with what it is now, should still 



THE GEOLOGICAL RECORD 205 

be in universal use among the geologists of the world. The 
exact limits of each of these great divisions have been more ac- 
curately determined, but the abrupt change in the life-forms, 
and the world-wide unconformity in the stratification on pass- 
ing from one division to the other, are as great as ever. Tlie 
Primary or Palaeozoic period is still that of fishes and Am- 
phibia; the Secondary or Mesozoic, that of reptiles, in 
amazing abundance and variety; and the Tertiary or Caino- 
zoic, that of an almost equal abundance of Mammalia, and 
with a considerable variety of insects and birds. 

The exceptions to the generality of this classification are 
few, and are particularly interesting. Of the myriads of rep- 
tiles that characterise the Secondary era, only two of the nine 
orders into which they are subdivided have been found so far 
back as the Permian, the latest of the Palaeozoic formations. 
One of these most primitive reptiles has a near ally in the 
strange, lizard-like Hatteria still surviving in some small 
islands on the coast of l^ew Zealand ; while others which seem 
to form connecting links with the earliest mammals may be 
the ancestral form from which have descended the unique 
types of the lowest living Mammalia, the omithorhynchus and 
echidna of Australia. 

So with the highest type of vertebrates, the mammals. 
About the middle of the nineteenth century small mammalian 
jaws with teeth were discovered in w^hat was known as the 
dirt-bed of the Purbeck (Jurassic) formation at Swanage; 
others in the Stonesfield Slate of the same fomiation; and at 
a later period very similar remains were found in beds of the 
same age (and also in the Cretaceous) in Xorth America. 
These are supposed to be primitive insect-eating Marsupials 
or Insectivora, and were all about the size of a mole or a rat; 
and it is a striking example of the imperfection of the geo- 
logical record, that although they occur through the whole 
range of the Secondary period, from the Trias to the Cre- 
taceous, their remains are still exceedingly scanty, and 
they appear to have made hardly any structural progress in 



206 THE WORLD OF LIFE 

that enormous lapse of time. Yet directly we pass from the 
Cretaceous to the Tertiary rocks, not only are Mammalia 
abundant and of fairly large size, but ancestral types of all 
the chief orders occur, and such highly specialised forms as 
bats, lemurs, and sea-cows (Sirenia) are found in its earliest 
division, the Eocene. 

Either there is no record of the missing links in the Sec- 
ondary formations, or, what is perhaps more probable, the 
break between the Secondary and Tertiary beds was of such 
enormous duration as to afford time for the simultaneous dvinsr 
out of numerous groups of gigantic reptiles and the develop- 
ment in all the large continents of much higher and more 
varied mammals. This seems to imply that a large portion 
of all our existing continents was dry land during this vast 
period of time ; the result being that the skeletons of very few 
of these unknown forms were fossilised; or if there were anv 
they have been subsequently destroyed by denudation during 
the depression and elevation of the land which we know to 
have occurred. 

We will now consider these great geological periods sep- 
arately, in order to form some conception of the changes in 
the world of life which characterised each of them. 

The Primary or Pdloeozoic Era 

The Palaeozoic differs from the two later eras of geology 
in having no known beginning. The earliest fossils are found 
in the Cambrian rocks ; they consist of a few obscure aquatic 
plants allied to our Charas and Algae, and some lowly marine 
animals allied to sponges, crinoids, and annelids. But there 
are also many forms of shell-bearing Mollusca, which had al- 
ready developed into the four great classes, lamellibranchs, 
pteropods, gasteropods, and cephalopods ; while some groups 
of the highly organised crustaceans were abundant, being rep- 
resented by water-fleas (ostracods) and numerous large and 
varied trilobites. Besides these, the curious Molluscoidea 
were fairly abundant, Terebratulae now first appear, and, as 



THE GEOLOGICAL EECORD 207 

well as the genus Lingnla, have continued to persist through 
all the subsequent ages to the present time. Great masses 
of rocks stratified and imstratified exist below the Cambrian, 
but have mostly been metamorphosed by internal heat and pres- 
sure, and contain no recognisable organic remains. 

Geologists have been greatly impressed by this sudden ap- 
pearance of marine life in such varied forms and compara- 
tively high organisation, and have concluded that the strati- 
fied formations below the Cambrian must probably have 
equalled the whole series which we now know above it. Dr. 
Croll declared, that " whatever the present mean thickness of 
all the sedimentary rocks of our globe may be, it must be 
small in comparison with tlie mean thickness of all the sedi- 
mentary rocks which have been formed " ; while Darwin says, 
" Consequently, if the theory be true, it is indisputable that 
before the lowest Cambrian stratum was deposited long periods 
elapsed, as long as, probably longer than, the whole interval 
from the Cambrian age to the present day, and that during 
these vast periods the world swarmed with living creatures." ^ 
This view was supported by Sir Andrew Eamsay, Director- 
General of the Geological Survey, who possessed unrivalled 
knowledge of the facts as to the geological record. He says, 
speaking especially of the fossil fauna of the Cambrian age : 

" In this earliest known varied life we find no evidence of its 
having lived near the beginning of the zoological series. In a 
broad sense, compared with what must have gone before, both 
biologically and physically, all the phenomena connected with this 
old period seem, to my mind, to be of quite a recent description; 
and the climates of seas and lands were of the very same kind 
as those the world enjoys at the present day." - 

This consensus of opinion renders it highly probable that 
the existing geological record only carries us back to some- 
where about the middle of the whole period during which life 
has existed upon the earth. 

1 Origin of Species, 6th ed. p. 286. 
2proe. Roy. Soc., 1874, p. 834. 



208 



THE WOELD OF LIFE 



Passing through the long series of Lower Silurian strata, 
(now separated as Ordovician) we have fuller developments 
and more varied forms of the same classes found in the Cam- 
brian; but in the Upper Silurian we meet with remains of 
fishes, the first of the great series of the vertebrates to appear 
upon the earth. Thej are of strange forms and low type, 
mostly covered with a kind of plate-armour, and apparentlv 
without any lower jaw. Hence they form a separate class — 
Agnatha (^^ without jaws"). They also appear to have had 
no hard, bony skeleton, as the only parts fossilised are the outer 
skin with its more or less armoured covering. The illustra- 
tion (Fig. 39) shows one of the simpler forms, the whole sur- 




FiG. 39. — Thelodus scoticiis. 
From Upper Silurian, Lanarkshire. Half nat. size. 



(B.M. Guide.) 



face being covered with small quadrangular flattened tubercles. 
The tail is somewhat twisted to show the bi-forked character. 
The mouth must have been an aperture underneath the head. 
Good specimens of these are rarely preserv^ed. 

In another family, Pteraspidse (Fig. 40), the skin-tubercles 




Fig. 40, — Pteraspis rostrata. 
From Old Red Sandstone of Herefordshire. One-third nat. size. (B.M. Guide.) 



are united into plates and scales, while the head is covered 
with a dorsal shield, often terminating behind in a spine ; 



THE GEOLOGICAL RECORD 



209 



and there is often a smaller shield beneath. A separate piece 
forms a projecting snout. 

The shields of these fishes are often preserved, while the 
complete body is very rare. 

Another gi'oup (Fig. 41) has the head shield continuous 




Fig. 41. — Ceplalaspis murchisoni. 
From Old Red Sandstone of Herefordshire. About half nat. szie. 



(B.M. Guide.) 



or in two pieces, while the skin-tubercles are united into vertical 
plates on the sides of the body, as in the species here sho^vn, 
while others have two or three rows of plates. 

The highest group of these primitive fishes has the head 
and fore part of the body covered with large polygonal bony 
plates. As these died out in the Devonian epoch their place 
was taken by true fishes, having an ossified skeleton, a movable 
lower jaw, gill-covers, and pairs of pectoral and anal fins rep- 
resenting the four limbs of reptiles and mammals. The ear- 
liest of these were allied to our sharks ; and at each succeeding 
geological stage a nearer approach was made to the higher 
types of our modern fishes. 

Class — Pisces 




Fig. 42.— Protocercal Tail. 
The primitive type of true fishes, having a lower jaw and paired fins. (B.M. Guide.) 




Fig. 43. — Heterocercal (unequal-lobed) Tail. 
The middle type of true fishes. (B.M. Guide.) 



210 



THE WOKLD OF LIFE 




Fig. 44. — Homocercal (equal-lobed) Tail. 

Modern type of true fishes. 

The older types persist in some of the lower forms. (B.M. Guide.) 



This advance in development is well indicated by the 
gradual changes in the tail, as shown in the accompanying 
figures (42-44). The upper one is the oldest; but it soon 
became modified into the second, which in various modifica- 
tions prevailed throughout the Palaeozoic and most of the Sec- 
ondary periods; while the third perfectly symmetrical type 
did not appear till near the end of the latter, and only became 
predominant, as it is now, in the Tertiary period. Many of 
the earlier forms have tails which are quite symmetrical ex- 
ternally, but show a slight extension of the vertebrae towards 
the upper lobe. All three forms still exist, but the third is by 
far the most abundant. 

In the highest Silurian beds land-plants allied to ferns and 
lycopods first appear, and with them primitive scorpions. In 
the succeeding Devonian and Carboniferous strata an ex- 
tremely luxuriant land vegetation of a low type appeared and 
covered a large part of the existing lands. This supported a 
large variety of arthropods as well as true insects allied to 
mayflies and cockroaches, with a great number of Crustacea. 
Here, too, we come upon the next great step towards the higher 
land animals, in the appearance of strange Amphibia forming 
a distinct order — the Labyrinthodontia. They appear to 
have outwardly resembled crocodiles or lizards, and were rather 
abundant during the Carboniferous and Permian eras, dying 
out in the subsequent Triassic. 

That portion of the Palaeozoic series of strata from the 
Silurian to the Permian, during which a rich terrestrial 
vegetation of vascular cryptogams was developed, with numer- 



THE GEOLOGICAL RECORD 211 

ous fonns of arthropods, insects, primeval fishes and am- 
phibians, comprises a thickness of stratified rocks somewhat 
greater than that of the whole of the Secondary and Tertiary 
strata combined. This thickness, which can ho measured with 
considerable approach to accuracy, is generally supposed to 
afford a fair 'proportionate indication of the lapse of time. 

There is a popular impression that in these remote ages the 
forces of nature were more violent, and their results more 
massive and more rapidly produced, than at the present time; 
but this is not the opinion of the best geological observers. 
The nature of the rocks, though often changed by pressure and 
heat, is in other cases not at all different from those of subse- 
quent ages. Many of the deposits have all the characters of 
having been laid down in shallow water, and in several cases 
footprints of Amphibia or reptiles have been preserved as well 
as impressions of raindrops, so exactly corresponding with those 
which may be seen to-day in suitable places, that we cannot 
suppose the operations of nature to have been more violent 
then than now. All our great coal deposits of PalaBOzoic age 
indicate long, and often repeated, but very slow depression of 
large areas of land, with intervening periods of almost perfect 
stability, during which dense forests had again time to grow, 
and to build up those vast thicknesses of vegetable matter 
which, when buried under successive rock-strata, became com- 
pressed into coal-seams, usually of several feet in tliickness. 

It is an extraordinary fact that in all the great continents, 
including even South America and Australia, coal-fields are 
more or less abundant at this period of the earth's history. 
This is proved by the identity or close similarity of the vege- 
tation and animal life, as well as by the position of the coal- 
beds, in regard to the strata above and beneath them. It is 
true that coal is also found in some Secondary and Tertiary 
strata, but these beds are much less extensive and the coal is 
rarely of such purity and tliickness ; while the later coal-fields 
are never of such world-wide distribution. Tt seems certain, 
therefore, that at this particular epoch there Avere some spe- 



212 THE WOELD OF LIFE 

cially favourable conditions, affecting the whole earth, which 
rendered possible a rapid growth of dense vegetation in all 
situations which were suitable. Such situations appear to 
have been extensive marshy plains near the sea, probably the 
deltas or broad alluvial alleys of the chief great rivers ; and the 
special conditions were, probably, a high and uniform tem- 
perature, with abundance of atmospheric moisture, and a larger 
proportion of carbon-dioxide in the air than there has ever 
been since. 

We may, in fact, look upon this period as being the neces- 
sary precursor of the subsequent rapid development of terres- 
trial and aerial animal life. A dense and moisture-laden 
atmosphere, obscuring the direct rays of the sun, together wdth 
a superabundance of carbonic-acid gas and a corresponding 
scarcity of free oxygen, would probably have prevented the 
full development of terrestrial life with its magnificent culmi- 
nation in such examples of vital activity as we see manifested 
in the higher mammalia, and especially in the more perfectly 
organised birds and insects. In this first and most widespread 
of the coal-making epochs we see the results of a world-wide 
and even cosmical adaptation which influenced the whole future 
course of life-development; while the later and more limited 
periods of coal-formation have been due apparently to highly 
favourable local conditions, of which the production of our 
deeper peat beds are the latest example. 

If then, as I am endeavouring to show, all life development 
— all organic forces — are due to mind-action, w^e must postu- 
late not only forces but guidance; not only such self-acting 
agencies as are involved in natural selection and adaptation 
through survival of the fittest, but that far higher mentality 
which foresees all possible results of the constitution of our 
cosmos. That constitution, in all its complexity of structure 
and of duly co-ordinated forces acting continuously through 
eons of time, has culminated in the foreseen result. ISTo other 
view yet suggested affords any adequate explanation ; but this 
vast problem will be more fully discussed later on. 



THE GEOLOGICAL EECORD 213 

This earliest, but, as some think, the most extended period 
of geological time, has been very cursorily touched upon, both 
because its known life-forms are more fragmentary and less 
generally familiar than those which succeeded them, and be- 
cause the object here is to show reasons for considering it as 
essentially 'preparatory for that wonderful and apparently sud- 
den burst of higher life-development of which we will now en- 
deavour to give some account. 

The Mesozoic or Secondary Formations 

When we pass from the Palaeozoic to the Mesozoic era we 
find a wonderful change in the forms of life and are trans- 
ported, as it were, into a new world. The archaic fishes 
wholly disappear, while the early Amphibia (Labyrinthodonts) 
linger on to the Trias, their place being taken by true reptiles, 
which rapidly develop into creatures of strange forms and 
often of huge dimensions, whose skeletons, to the uninstructed 
eye might easily be mistaken for those of Mammalia, as in fact 
some of them have been mistaken. The earliest of these new 
types, somewhat intermediate between Amphibia and reptiles, 
appear in the latest of the Palaeozoic strata — the Permian. 
These are the Theriomorpha (or "beast-shaped'' reptiles), 
which show some relationship to true mammals which so quickly 
followed them in the lowest of the Mesozoic strata. 

These early reptiles already show a large amount of speciali- 
sation. Some have greatly developed canine teeth, almost 
equalling those of the sabre-toothed tiger; others were adapted 
to feed on the luxuriant vegetation of the period, while their 
short, massive limbs made them almost as clumsy-looking as 
the hippopotamus. These strange creatures were first discov- 
ered in the Karoo formation of the Cape Colony, but have been 
found in a few places in India, Europe, and Xorth America, 
always either in the highest Primary (Permian) or lowest 
Secondary formation (Trias). Pemains of allied forms have 
been found in the north of England and in the Trias of Elgin, 
Scotland. Their nearest survivimr relatives arc supposed to 



214: THE WOKLD OF LIFE 

be the monotremes (echidna and platypus) of Australia, jet in 
the whole series of stratified rocks of Secondary and Tertiary 
times no intermediate form has yet been discovered. 

A complete skeleton of one of the largest of these beast- 
shaped reptiles is represented here (Fig. 45). The body of this 
strange animal was nearly seven feet long, and its small teeth 
show it to have been a vegetable feeder. The total length of 
some specimens was nearly ten feet, and the immense limbs 
were apparently adapted for digging, so that in loose soil it 
mav have been of subterranean habits. In the same forma- 
tion other allied but much smaller species were found. 

Along with these w^ere many creatures of the same general 
type, but as clearly carnivorous as the others were herbivorous. 
About a dozen distinct genera have been characterised, and as 
each probably comprised several species, and as these have as 
yet been all obtained from a few very limited areas, it is quite 
possible that the land animals of the Cape Colony at that 
early period may have been almost as numerous, as varied, and 
as conspicuous as they are to-day. 

The two skulls here figured (Figs. 46 and 47) are of very 
different forms, and must have belonged to animals about the 




Fig. 46. — Dicynodon lacerticeps (Order — Anomodontia). 
From Karoo formation (Trias), South Africa. One-third nat. size. (B.M. Guide.) 

size of wolves; but there were many others of various shapes 
and sizes, some even equalling that of a large crocodile. 

But at the same epoch, apparently, Europe and North Amer- 
ica were equally well supplied w^ith these strange reptiles, Ira, 



•iiopouBn.§i aq; jo aouB.iBaddv 9iqi?qo.ij — -jc -oij 




(•9pinjc) 'H'a) "auids i^uoiB laaj 08 •q^Sueq; •uiniS[aa; Jo uapiBa^i eq; mox^ 

• ( siaudj. 
-jivasnudfi uopounn^i) .iuusouiq snopocToq^ui.iQ jo iio;e[9>^s — -qo -oij 




THE GEOLOGliCAL KECOiilJ lM:. 

Europe till recently only a few isolated bones or fragments of 
skulls bad been discovered, but about five or six years ago a 
rich deposit was found on the banks of the river Dwina in 
^N^orthern Kussia. Tn a large fissure of the rocks quantities 




Fig. 47. — J^lusaurus felinus (Order — Anomodontia). 
From Trias (South Africa). Two-thirds nat. size. (B.M. Guide.) 

of nodules of very hard rock had been found, and being easy 
to obtain, were broken up for mending roads; till Professor 
Amalitzky from Warsaw, visiting the spot, found that each 
of these nodules contained well-preserved fossils of extinct ani- 
mals, which proved to be reptiles of the very same group as 
those of South Africa. Some of these nodules contained a 
skull; others contained the whole skeleton, these being some- 
times eight feet long, and of strange forms corresponding to 
the crushed or distorted body of the animal. Thenceforth 
Professor Amalitzky devoted himself to the work of explora- 
tion by the aid of a grant from the Imperial Academy of St. 
Petersburg. The nodules are taken to Warsaw, where ihey 
are carefully opened, and the fossilised bones extracted, 
cleaned, and put together. Some of these are found to be 
almost identical with those of South Africa; others, quite 
distinct, though allied. Fig. 48 represents the skull of a huge 
carnivorous reptile, which must have been about the same size 
as the herbivorous Pariasauri fabundantly preserved in tho 
nodules), upon which it doubtless preyed. As the skull is two 



216 THE WOKLD OF LIEE 

feet long, and the whole head and body about nine feet, it must 
have far exceeded in size the largest lion or tiger, and prob- 
ably that of any carnivorous land mammal that has ever lived. 

In I^orth America these reptiles were also present in consid- 
erable abundance. Some, forming the sub-order Theriodontia, 
were allied to the Pariasauri, and were probably herbivorous; 
while the Pariotrichida? were carnivores, as were also a very 
distinct family, the Clepsydropidse. Of this latter group one 
1 genus, Dimetrodon, is here figured as restored by Sir Ray 
Lankester (Fig. 49). This is supposed to be allied to the liv- 
ing Hatteria of New Zealand. These strange carnivorous rep- 
tiles of this early period may have preyed upon numerous 
herbivores which have not been preserved, as well as upon the 
primitive insects and land Crustacea, which at this period were 
probably abundant. 

The remarkable thing is, that some hundreds of species of 
varied form and size, herbivorous and carnivorous, should have 
been gradually developed, arrived at maturity, and completely 
died out, during the comparatively short periods of the Permian 
and Trias, or the interval between them. 

It is probable, however, that these transition periods really 
occupied a very great length of time, since all known reptiles 
seem to have originated during this era, though owing to unfa- 
vourable circumstances the connecting links have rarely been 
preserved. The singular Chelonia (turtles and tortoises) ap- 
pear fully formed at the end of the Trias or in the earliest 
Jurassic beds, as do the crocodiles, the aquatic Plesiosaurians 
and Ichthyosaurians, the flying Pterodactyls, and the huge 
Dinosaurs. All these have more or less obscure interrelations, 
and their common ancestors cannot well be older than the 
Permian, since the preceding Carboniferous offered highly 
favourable conditions for the preservation of the remains of 
such land animals had they existed. To bring about the modi- 
fication of some primitive reptile or amphibian into all these 
varied forms, and especially to bring about such radical changes 
of structure as to develop truly aerial and truly oceanic rep- 



-^^wy^jrw — *-« »~ 



~i 




fUi 



Fig. 48. — Skull of the gigantic Theriomorpli Carnivorous Reptile 

Inostransevia. 
From Northern Russia. (Length of skull, 2 feet.) Permian or Triassic age. This 
animal was probably as large as a rhinoceros. (From Sir Ray Lankester's 
Extinct Animals.) 




Fig. 49. — Probable Appearance of the Therioniorj)!! KcitliU' Dinietroilon. 
From the Permian of Texas. It was the size of a large dog. (From Sir Kay Lan- 
kester's Extinct Animals.) 



THE GEOLOGICAL RECORD 217 

tiles, must, with smy reasonable speed of change, have required 
an enormous lapse of time, yet all these had their origin seem- 
ingly during the same period. Some account of the strange 
animals whose abundance and variety so especially character- 
ised the Secondary period will now be given. 

Order — Dinosauria 

Some of the best known of these reptiles have been found 
in our own country, and we will therefore begin with the 
Iguanodon, of which teeth and bones were found near Maid- 
stone (Kent) by Dr. Mantell in the early part of the last 
century, but no complete skeletons have been found. A 
closely allied species from Belgium of the same age (the 
Wealden) is here figured (Fig. 50). It was about thirty foot 
long, and is believed to have walked chiefly on its hind feet, 
and to have fed upon the foliage or fruits of good-sized trees. 
As shown in the restoration of the animal in its supposed usual 
attitude when alive (Fig. 51), it would stand about fourteen 
feet high. The fore-limbs are comparatively small, termi- 
nating in a hand of five fingers, the thumb being represented 
by a bony claw. The much longer hind legs, however, have 
feet with only three toes, much resembling those of running 
birds, and numerous impressions of such feet have been found 
in rocks of the same age, hence the group to which it belongs 
has been named Ornithopoda or '^ bird-footed.'' From the 
character of these it seems probable that the animal would 
walk on all fours and leap with its hind legs in the manner 
of a kangaroo. 

The skull as shown by Fig. 52 is three and a half feet long, 
and the numerous close-set serrated teeth seem well adapted 
for grinding up large quantities of vegetable matter. The 
deep compressed tail indicates that it may have been used for 
swimming, and that the animal frequented lakes or marshes, 
and perhaps escaped its enemies by taking to the water. It 
appears to have had no protective armour. 

Another group was named Stegosauria, " plated lizards," 



218 



THE WORLD OF LIFE 



from tlieir protective armour, a skeleton of whicli Is figured 
(Fig. 53). It has long bony spines on the shoulders, which, 
if bearing a horny covering, would have been an effective pro- 
tection against beasts of prey; and this is followed by a row 




Fig. 52. — Skull of I guanodon bernissartensis. 
From the Wealden of Belgium. Three and a half feet long. (B.M. Guide.) 




Fig. 53. — Skeleton of Armoured Dinosaur {Scelidosaurus harrisoni). 
From the Lower Lias of Charmouth, Dorset. Length along spine, about 13 feet; 

height as drawn, 7 feet, (B.M. Giiide.) 



I— I 

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THE GEOLOGICAL RECORD 



219 



of bony knobs on the sides, which also probably carried spines 
protecting the vital organs. A row of similar bones along each 
side of the powerful tail may also indicate spines, which would 
have rendered this an effective weapon against an encmv from 
the rear. In another allied species, of which the skull is hero 
shown (Eig. 54), there were two enormous horns above the 
eyes and a smaller one upon the nose; while the margin of 




Fig. 54. — Skull of Horned Dinosaur (Sterrolophus flabellatus). 
From the Upper Cretaceous of Wyoming, U.S.A. (B.M. Guide.) 

the bony expansion behind seems to have borne a row of spiny 
plates. 

As an illustration of how these huge but ratlior w(>ak vege- 
table feeders ^vere protected, the above restoratiou uiny bo use- 
ful, especially w^hen we remember that the species above tigured 
was as bulky as a rhinoceros or elephant. It was found in 
the Upper Jurassic strata of Xorth America. 



We now come to some of the largest laud-auiiual> which 
ever lived upon the enrth — the Snuropodn, or liznrd-footed 
Dinosaur — and these were more or less amphibious. One of 



220 THE WORLD OF LIFE 

the most singular of these is the Brontosaunis, the skeleton of 
which is here represented. It is said to have the smallest head 
in proportion to the body of any vertebrate animal. Pro- 
fessor O. C. Marsh, who discovered it, states that the entire 
skull is less in diameter or weight than the fourth or fifth 
neck vertebra, while the brain-cavity is excessively small. He 
says : '^ The very small head and brain indicate a stupid slow- 
moving reptile. The beast was wholly without defensive or 
offensive weapons or dermal armour. In habits it was more 
or less amphibious, and its remains are usually found in local- 
ities w'here the animals had evidently become mired." 

A creature nearly as large was the Cetiosaurus leedsi, from 
the Oxford clay near Peterborough, of which the left hind limb 
and the larger part of the tail are mounted in the British 
Museum. It measures 10 feet 6 inches high at the hip, and 
must have been nearly 60 feet long. Still larger was the Amer- 
ican Atlantosaurus immanis, of w^hich only fragmentary por- 
tions have been obtained; but a complete thigh-bone, 6 feet 
2 inches long, is the largest yet discovered. It was found in 
the Upper Jurassic strata of Colorado, U.S.A. 

The largest complete skeleton is that of the Diplodocus car- 
negii, now w-ell known to all who have recently visited the 
British ^Natural History Museum, where a model of it is 
mounted, as shown in the photographic picture of it here repro- 
duced. It is SO feet in length, both neck and tail being enor- 
mously long in proportion to the body. It is supposed that it 
would have been unable to walk on land except very slowly, 
and that it inust have lived chiefly in the water on juicy water- 
weeds, which its very weak teeth, as shown in the above figure 
of the skull, would alone have been such as it could graze on. 
The very long neck would have enabled it to gather such food 
from moderately deep water. The brain occupied the small 
space between and behind the eyes (Fig. 58). 

These huge reptilian herbivora, feeding in marshes, lakes, 
or shallow seas, w^ere preyed upon by the numerous crocodiles 
which lived throughout the same j)criods and are everywhere 




Fig. od. — Probable Appearance of the Jurassic Dinosaur Stegosaurus. 

The hind leg alone is twice the height of a well-grown man. 

(From Sir Ray Lankester's Extinct Animals.) 



1 1 



THE GEOLOGICAL RECORD 



221 



found in the same strata. They were of varied forms and 
sizes, but as they did not differ much in appearance from the 
various crocodiles and alligators now living in the tropics they 






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need only be mentioned. But besides these there were true 
Dinosaurs of similar shape to tlie Tguanodon, but of rather less 
massive form and with strong teeth curved backward, which 



222 



THE WORLD OF LIFE 



Avitli tliolr wicle-openlng jaws evidently adapted them to seize 
and prey ujDon the larger land-reptiles. These form the Sub- 




FiG. 58. — Skull of Sauropodous Dinosaur {Diplodocus) . 
From the Upper Jurassic of Colorado, U.S.A. One-sixth nat. size. (B.M. Guide.) 




Fig. 59. — Skull of a Theropodous Dinosaur {Ceratosaurus nasicornis). 
From the Upper .Jurassic of Colorado, U.S.A. One sixth nat. size. (B.:\r. Guide.) 

order Theropoda, or beast-footed Dinosaurs. The skull of one 
of these here shown (Fig. 59) is more than 2 feet long, but 




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THE GEOLOGICAL EECORD 223 

no complete skeleton has been jet discovered. The allied 
Megalosaurus was found by Dr. Bnckland in the Weahh'ii 
beds in such abundance that he was able to piece together 
enough of the skeleton to show its affinity to the Iguanodon. 

Order — Sauropterygia 

We now come to the group of aquatic lizards wdiich abounded 
in all the seas of the Mesozoic period from the Trias to the 
Chalk. They had lizard-like heads, powerful teeth, both fore 
and hind limbs converted into paddles, and often with a dilated 
swimming tail. They varied much in size, but were often 
very large. Plesiosaurus cramptoni, from the Upper Lias of 
Whitby, w^as 22 feet long, but some species from the Chalk 
formation were from 30 to 40 feet long. A skull and jaws 
of P. grandis, from the Kimmeridge clay, is 6 feet long, which, 
if the proportions were the same as those of the species here 
represented (Fig. 60), w-ould have belonged to an animal nearly 
50 feet long. The whole group w^as extremely varied in form 
and structure, but all w^ere adapted for preying upon such 
aquatic or marsh-frequenting animals as abounded during the 
same period. 

Order — Ichthyopterygia 

All the members of the preceding order have the paddles 
supported by a complete bony foot or hand composed of five 
separate fingers and connecting wrist-bones. But in the pres- 
ent order the adaptation to marine life is more perfect, a dorsal 
fin and bi-forked tail having been developed (Fig. 61), while 
the bony skeleton of the four limbs often consists of seven or 
eight rows of polygonal bones closely fitted together as shown 
in the drawings here reproduced (Fig. 62 A, B). They were 
also remarkable for their verv larG:e and hiffhlv oro-anised eves, 
which, with the lengthened jaws and closely set sharp teeth, indi- 
cate a perfect adaptation for capturing the fishes which the seas 
of that age no doubt produced iu the same abundance and almost 
as great variety as our own. These creatures also varied uiuch 



224 



THE WOKLD OF LIFE 



B 



in size and shape, one from the Lower Lias of Warwickshire 
being 22 feet long, but detached vertebra? sometimes indicate 

a much larger size. In 
the older Triassic beds 
smaller species are found 
which were less completely 
aquatic ; and these seem to 
show an affinity to Am- 
23hibia rather than to rep- 
tiles, indicating that the 
two aquatic orders may 
have had independent ori- 
gins. 

Still later, in the Cre- 
taceous formation, there 
were other aquatic reptiles 
quite distinct from all the 
preceding, and more al- 
lied to our living lizards, 
having well-formed swim- 
ming feet, but snake-like 
bodies. These serve to in- 
dicate how completely the 
?'^-.?^-~?^S'H^,''''^ ^^^ and Hind (B) reptiles of the Secondary 

Paddles of Ichthyosaurus intermedius. ^ 

From Lower Lias of Lyme Regis. One-third CpOCh OCCUpicd the plaCC 
nat. size. (B.M. Guide.) n^^ ^ ^ ,^ T\r 

now nlled by the J\lam- 
malia, somewhat similar forms adapted for aquatic life being 
again and again developed, just as the Mammalia subsequently 
developed into otters, seals, manatees, porpoises, and whales. 





Order — Ornithosauria 

We come finally to one of the most remarkable developments 
of reptilian life, the bird-lizards, more commonly known as 
Pterodactyls, which accompanied all the other strange forms 
of reptilian life in the Mesozoic period. They are first found 
a little later than the earliest Dinosaurs, in the Lowc-r Lias of 








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THE GEOLOGICAL RECORD 






Bavaria; but as they are, even then, fully developed, though 
small, there must have been a long series of intennediate forms 
which probably reached back to the Triassic if not to the 
Permian era. 




Fig. 63. — Skeleton of Pterodactylus spectahilis. 
From the Upper Jurassic of Bavaria. Nat. size. This early form has teeth and a 
very short tail, and the body was not larger than that of a sparrow. (B.M. 
Guide.) 

The illustration of the skeleton of one of these early forms 
on this page is of the natural size (Fig. 63), Tt shows the 
greatly elongated fifth finger to which the wing-membrane was 
attached. In this form there were small teeth in the jaws, and 
the tail was very short. 



OQfi 



THE WORLD OF LIFE 




Fig. 64. — Restoration of a Long- Tailed Pterodactyl {Rhamphorhynchus 

'phyllurus ) . 

From the Upper Jurassic of Bavaria. (B.M. Guide.) Expanse of wings more than 
2 feet. The long tail has a terminal web, shown in casts in fine lithographic 
stone. 



The above restoration (Fig. 64), shows a larger species from 
the Jurassic formation, at which period they were more varied. 
This had a very long tail with a dilated membrane at its tip. 
Allied species, with a long pointed tail, have been found in 
the Lias of Lyme Regis, and also at Whitby. 




Fig. 65. — Toothless Pterodactyl {Pteranodon occidentalis) . 

From the Upper Cretaceous of Kansas, U.S.A. (B.M. Guide.) 



It was not till the Cretaceous period that the Pterodactyls 
reached their greatest size, the species figured here having an 
expanse of eighteen feet ; and these large forms have a pow- 
erful but toothless beak (Fig. 65). 

Fragments of bone from the English Chalk indicate an 



THE GEOLOGICAL REC0RT3 



227 



equally large size. The backward prolongation of the head is 
supposed to show that the powerful muscles required for such 
immense wings were attached to the head. This is rendered 
more probable by the skull, nearly 4 feet long, of another still 
larger species, in which the occipital crest projects a foot back 
from the head, and which Professor ^Farsli believes had a 
spread of wdng of 20 or even 25 feet (Fig. 66). 




Fig. 66. — Lateral View of Skull of Pteranodon longiceps. 

From the Cretaceous of North America. One-twelfth nat. size. The jaws are en- 
tirely without teeth. There is an enormous occipital crest (c) projecting far 
behind the occiput, to which the mirscles for flight were probably attached; (a) 
the nares and pre-orbital cavity; (&) the orbit. This species had an expanse 
of wings of about 20 feet. (From Nicholson's Manual of Palaeontology.) 



We thus see that during the Secondary epoch the great class 
Reptilia, wdiich had originated apparently during the last 
stages of the Primary, became developed into many special 
types, adapted to the varied modes of life wdiich the higher 
warm-blooded vertebrates have attained in our own time. The 
purely terrestrial type had their herbivora and carnivora cor- 
responding to ours in structure and habits, but surpassing them 
in size; the amphibious or marsh species surpassed our largest 
existing crocodiles, while the true aquatics almost exactly an- 
ticipated the form and habits of our porpoises and smaller 
whales. The air, too, was peopled by the strange Pterodactyls 
which surpassed the bats in powers of flight, in which they 
almost rivalled the birds, while they exceeded both in the enor- 
mous size thev attained. Considering how rare must have been 
the circumstances which led to tlie preservation in the rocks of 
these aerial creatures, we may conclude, from the large number 
of species known to us, that they \u\\<\ have been extremely 
abundant in middle and late ^Icsozuic times, and that they 



228 THE WORLD OF LIFE 

occupied almost as important a place in nature as do tlie birds 
now. Yet not one of the varied forms either of the terrestrial 
Dinosaurs, the aerial Pterodactyls, or the aquatic Sauroptery- 
gia and Ichthyopterygia — all abounding down to Cretaceous 
times — ever survived the chasm that intervened between the 
latest Secondary and the earliest Tertiary deposits yet discov- 
ered. This is perhaps the most striking of all the great geolog- 
ical mysteries. 

One more point may here be noticed. The early small- 
sized Pterodactyls arose just when highly organised winged 
insects began to appear, such as dragon-flies and locusts, soon 
followed by wasps, butterflies, and two-winged flies in Middle 
Jurassic times ; from which period all orders of insects were 
no doubt present in ever-increasing numbers and variety. 

It is interesting to note further, that at the very same epoch 
in which we find this great increase of insect life there ap- 
peared the first true flowering plants allied to the Cycads, with 
which they were till quite recently confounded. These also 
must have rapidly developed into a great variety of forms, 
since in the later Cretaceous formation in many parts of the 
world true flowering plants, allied to our magnolias, laurels, 
maples, oaks, walnuts, and proteaceous plants, appear in great 
abundance. These seem to have originated and developed very 
rapidly, since in the earliest deposits of the same formation 
none of them occur. 

Mesozoic Mammalia 

There is perhaps nothing more remarkable in the whole 
geological record than the fact of the existence of true mam- 
mals contemporaneous with the highly diversified and abundant 
reptile life throughout the period of their greatest development 
from the Trias to the Cretaceous. They were first discovered 
nearly a century ago in the Stonesfield Slate at the base of the 
Great Oolite in Oxfordshire, and were described under the 
names Amphitherium and Phascolotherium (Fig. 67). About 
forty years later a considerable number of similar remains 




Fig. 67. — Lower Jaw of Phascolotherium bucklundi. 
Prom the Stonesfield Slate (Lower Jurassic), Oxfordshire. Outline fig. nat. size. 

(B.M. Guide.) 



c? 




Fig. 68. — Lower Jaw and Teetli of IS i><i Uic other ium tricuspidcus. 
From the Purbeck beds (Upper Jurassic) of Swanage. Outline fig. nat. size; c and 
d being lateral and upper views of a molar tooth. (B.if. Guide.) 







f.ic Vff -x.^<~' -^ — ^ ■_ .,--,, . fiiiiii I 111 I 11 ^M" -tmii 



Fig. 69. — Lower Jaw oi Ti iconodon fnoidujc. 
Purbeck of Swanage. Nat. size. (B.M. Guide.) 



THE GEOLOGICAL RECORD 229 

• — small mammalian jaws with teeth — were found in what 
is termed the dirt-bed at Swanage, in the upper part of the 
Jurassic formation. Two of these — Spalucotherium and 
Triconodon — are here represented, and show how well thej 
are preserved (Figs. 68 and G9). Another of a different type 
(Plagiaulax) has been also found in a much older formation 
in Somersetshire — the Rhetic or Upper Trias — and in beds 
of the same age in Bavaria, near Wiirtemberg. Both these 
types of jaw have been since found in considerable abundance 
in the Jurassic beds of W^'oming, U.S.A. These materials 
have enabled palaeontologists to decide that the former group 
were really of the marsupial type, while the latter (and 
earlier in time) belong to a distinct sub-class, the Multituber- 
culata, from the curiously tubercled teeth, resembling those of 
the Australian ornithorhvnchus. Somewhat similar teeth and 
jaws have been found also in the Upper Cretaceous beds of 
!N"orth America. 

N^ow it is quite certain that these small mammals, so widely 
spread over the northern hemisphere, must have been devel- 
oped through a series of earlier forms, thus extending back 
into that unknown gap between the Palaeozoic and Mesozoic 
eras, and being throughout contemporaneous ^vith the great Age 
of Reptiles w^e have just been considering. Yet during the 
whole of this vast period they apparently never increased be- 
yond the size of a mouse or rat, and though they diverged 
into many varied forms, never rose above the lowly types of 
the monotremes or the marsupials ! Such an arrest of develop- 
ment for so long a period is altogether unexampled in the geo- 
logical record. 

The Earliest Birds 

Birds present us with a similar problem, but in their case 
it is less extraordinary because their ])reservation is so much 
more rare an event, even in the Tertiary period, when we 
know thev must have been abundant. The verv earliest-known 
fossil bird is from the Upper Jurassic of Bavaria, and is beau- 



230 



THE WORLD OF LIFE 




Fig. 70.— Drawing of the Fossil Lizard-Tailed Bird {Arcliceopteryx 

macrura ) . 

From the lithographic stone beds of Bavaria (Upper Jurassic). About one-fourth 

nat. size. lu the Nat, Hist. Museum. (B.M. Guide.) 



THE GEOLOGICAL KECOliD 231 

tifully preserved in the fme-gi'aiued beds of lithographic stone. 
The accompanying ilhistration is from an exact drawing of this 
specimen (Eig. TO), in order to render more distinct the details 
very faintly shown in the original. To the anatomist every 
bone or fragment of a bone is recognisable ; while the mimis- 
takable feathers, and the foot with the increasing number of 
joints from the inner to the outer toe, are sufficient to show 
that it is a true bird, notwithstanding its curiously elongated 
tail feathered on each side. In this specimen there is no sign 
of the head ; but fortunately another specimen has recently 
been found, in which the skull is well preserved, and which 
shows that the beak was armed with teeth (Fig. 71). Later 
on, in the Cretaceous for- 
mation of Kansas, U.S.A., 
some well-preserved aquatic 
birds have been found. 
One is of large size (about 
1 feet high), something like 
a diver, but with flat 
breastbone, and therefore 

probably with rudimentary Fig. 71.— Skull of Archwopteryx 
wings; another, much ^ siemensi, showing Teeth. 

_ From the lithographic stone (Upper Jurassic) 

smaller, has long wing- of Bavaria. Xat. size. Original in the 

1 1 11111 Berlin Museum. (B.]\r. Guide.) 

bones and a deeply keeled 

sternum. The bonv tail of 

these is not much longer than in living birds, but in both the 

beaks are toothed. 

The main reason for the extreme rarity of bird-remains in 
the Mesozoic era is, that being so light in body and plumage 
they could very rarely be presei'\Td. Those tliat died in or 
on the margins of rivers or lakes, or wdiich fell into the water, 
would be at once devoured bv the fishes or the aquatic or aerial 
reptiles which seem to have swanned everywhere. 




232 THE WORLD OF LIFE 

Concluding Remarks on Mesozoic Life-Development 

The remarkable series of facts wliicL have now been sum- 
marised, and which have been largely due to researches in 
Xorth America, South Africa, and Europe during the last 
twenty or thirty years, are of such a nature that they seem 
to call for some cosmical explanation similar to that suggested 
to account for the vast development of cryptogamous vegetation 
towards the close of the Palseozoic era. The facts are in many 
respects strikingly parallel. We find in the Carboniferous 
series of rocks a storing-up of vast masses of vegetable matter 
in the form of coal, which is unique in the whole past history 
of the earth, and this was at a time when the only land verte- 
brates were archaic forms of amphibians. Almost immediately 
after the deposit was completed true reptiles appeared all over 
the earth, and rapidly develoj^ed into that " Age of Eeptiles " 
which is perhaps the greatest marvel of geological history. 
Birds and Mammalia also started into life, apparently branch- 
ing off from some common stock with the reptiles. Then, 
during that blank in the record separating the Secondary from 
the Tertiary era, the whole of this vast teeming mass of rep- 
tilian life totally disappeared, with the two exceptions of the 
crocodiles and the tortoises, which have continued to maintain 
themselves till our own day, w^hile true lizards and snakes, 
which are not known in earlier times, became the predominant 
forms of reptilian life. It was during the same blank period 
of the geological record that mammals and birds sprang into 
vigorous and diversified life, just as the reptiles had done 
during the blank between the Primary and Secondary eras. 
To complete the great series of life-changes (perhaps as a nec- 
essary preparation for them), plants underwent a similar trans- 
formation; the prominent Cryptogams, Conifers, and Cycads 
of the Secondary era gave way towards its close to higher flow- 
ering plants, which thenceforth took the first place, and now 
form probably fully 99 per cent of the whole mass of vegeta- 






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THE GEOLOGICAL EECOKD 233 

tion, with a variety of nourishing products, in foliage, fruit, 
and flower, never before available. 

Now here we have a tremendous series of special develop- 
ments of life-forms simultaneous in all parts of the earth, 
affecting both plants and animals, insects and vertebrates, 
whether living on land, in the water, or in the air, all contem- 
poraneous in a general sense, and all determining the transi- 
tion from a lower to a very much higher grade of organisation. 
Just as in the first such great step in advance from the '' age 
of fishes " to the '' age of reptiles " we see reason to connect 
it with the change from a more carbonised to a more oxygen- 
ated atmosphere, produced by the locking up of so much carbon 
in the great coal-fields of the world ; so, I think, the next groat 
advance was due to a continuation of the same process by a 
different agency. Geologists have often remarked on the pro- 
gressive increase in the proportion of limestone in the later 
than in the earlier formations. In our own country w^e see a 
remarkable abundance of limestone during the Secondary era, 
as shown in our Lias, Oolites, Portland stone, and Chalk rocks ; 
and somewhat similar conditions seem to have prevailed in 
Europe, and to a less extent in Xorth America. As limestone 
is generally a carbonate of lime, it locks up a considerable 
amount of carbon which might otherwise increase the quantity 
of carbonic acid in the atmosphere ; and as lime, or its metallic 
base, calcium, must have formed a considerable portion of the 
original matter of the earth, solid or gaseous, the continued 
formation of limestone through combination with the carbonic 
acid of the atmosphere must have led to the constant diminu- 
tion of that gas in the same way that the formation of coal 
reduced it. 

It seems probable that when the earth's surface was in a 
greatly heated condition, and no land vegetation existed, the 
atmosphere contained a much larger proportion of carb(m- 
dioxide than at present, and that a continuous reduction of 
the amount has been going on, mainly through the extraction 



234 THE WOKLD OF LIFE 

of carbon from the air by plants and from the water by marine 
animals and by chemical action. The superabundance of this 
gas during the early stages of the life-world facilitated the 
process of clothing the land with vegetation soon after it ap- 
peared above the waters; while its absorption by water was 
equally useful in rendering possible the growth of the calcare- 
ous framework or solid covering of so many marine animals. 
With the progressive cooling of the earth and the increased 
area of land-surface, more and more of the atmospheric carbon 
became solidified and inactive, thus rendering both the air and 
the water better fitted for the purposes of the higher, warm- 
blooded, and more active forms of life. This process will, I 
think, enable us partially to understand the fundamental 
changes in life-development which characterised the three great 
geological areas; but it does not seem sufficient to explain tbe 
very sudden and complete changes that occurred, and, more 
especially, the almost total extinction of the lower or earlier 
types just when they appear to have reached their highest and 
most varied structure, their greatest size of body, and their 
almost world-wide distribution. Before attempting a solution 
of this difficult problem an outline must be given of the latest, 
and in some respects the most interesting, of the geological 
eras — the Tertiary, or, as more frequently termed by geolo- 
gists, the Cainozoic. 



CHAPTER XII 



LIFE OF THE TERTIARY PERIOD 



Directly we pass from the Cretaceous into the lowest of the 
Tertiary deposits — the Eocene — we seem to be in a new 
world of life. Xot only have the whole of the gigantic Dino- 
saurs and the accompanying swimming and flying reptiles 
totally disappeared, but they are replaced in every part (tf the 
world by Mammalia, which already exhibit indications of being 
the ancestors of hoofed animals, of Carnivora, and of Quadru- 
mana. 

Order — Ungulata 

In the Lower Eocene strata of ISTorth America and Europe, 
the sub-order Condylarthra is well represented. These were 
primitive, five-toed, hoofed animals which, Dr. A. Smith Wood- 
ward tells us, '" might serve well for the ancestors of all later 
Uiigulata." One of these, Phenacodus primcevus, was found 
in the Lower Eocene of Wyoming, U.S.A., and was about 4 
feet long exclusive of the tail (see Eig. 72). Considering that 
this is one of the very earliest Tertiary mammals yet discov- 
ered, it is interesting to note its comparatively large size, its 
graceful form, its almost full series of teeth, and its large five- 
toed feet; affording the starting-point for diverging modifica- 
tion into several of the chief types of the higher mammalia. 
So perfectly organised an animal could only have been one of 
a lono^ series of forms brido:inc: over the 2:reat c'ulf between 
it and the small rat-like mammals of the ^lesozoic period. 

Another sub-order is the Amblypoda, of which the Corypho- 
don of Europe and Xorth Americn is one of the best known. 
This was about 6 feet long, and was first obtained from our 

235 



206 



THE WORLD OF LIFE 



London Claj. It had a heavy body, five-toed stumpy feet, 
and a complete set of 22 teeth in each jaw adapted for a vege- 
table diet ; but no defensive tusks or horns. Other allied spe- 
cies were much smaller, and all were remarkable for a very 

small brain. 

But a little later, in the Middle Eocene of North America, 
they developed into the most wonderful monsters that have ever 




Fig. 73. — Uintatherium ingens. 
Eocene of Wyoming, U.S.A. One-thirtieth nat. size. (B.M. Guide.) 

lived upon the earth — the Dinocerata or '^ terrible-horned " 
beasts. These had greatly increased in size; they often had 
large tusks in the upper jaw ; and horns of varied forms and 
sizes were developed on their heads. The tusks were some- 
times protected by a bony flange projecting downwards from 
the lower jaw immediatelv behind it, as well sho^vn in the 
figure here given of Uintatherium ingens. This animal must 
have been about 11 feet long and nearly 7 feet high; and if 
the six protuberances of the skull carried horns like our 
rhinoceroses, it must, indeed, have been a '' terrible '' beast, 



LIFE OF TERTIARY PERIOD 






The imperfect skull of another species (Fig. 74) shows even 
larger the honj horn-cores presenting all tlie appearance of 
having carried some kind of horns. This seems the more 
probable, as many of the species had no tusks, and in that case 
mere rounded bony protuberances would have been of little 




Fig. 74. — Uintatherium cornutum. 
From the Middle Eocene of Wyoming, U.S.A. (Nicholson's Palaeontology.) 

protective use. Figure 75 (on p. 238) represents the skeleton 
of one of the largest species without tusks. From the scah^ 
given, it must have been 11 or 12 feet long and nearly 8 feet 
high. 

Professor Marsh informs us that these strange-homed ani- 
mals have been found onlv in one Eocene lake-basin, in 
Wyoming, U.S.A. He says: 

"These gigantic beasts, which nearly equalled the elephant in 
size, roamed in great numbers about the borders of the anciout 



238 



THE WOKLD OF LIFE 



tropical lake in which many of them were entombed. This lake- 
basin, now drained by the Green Eiver, the main tributary of the 
Colorado, slowly filled up with sediment, but remained a lake so 
long that the deposits formed in it during Eocene time reached a 




LIFE OF TERTIAEY PEETOD 239 

vertical thickness of more than a mile. ... At the present 
time this ancient lake-basin, now 6000 to 8000 feet above the sea, 
shows evidence of a vast erosion, and probabl}^ more than one-half 
of the deposits once left in it have been washed away, mainly by 
the action of the Colorado River. What remains forms one of 
the most picturesque regions in the whole West, veritable mauvaises 
terres, or bad lands, where slow denudation has carved out cliffs, 
peaks, and columns of the most fantastic shapes and colours. This 
same action has brought to light the remains of many extinct 
animals, and the bones of the Dinocerata, from their great size, 
naturally first attract the attention of the explorer." 

As regards the mental powers of these strange animals, Pro- 
fessor Marsh saj's: 

" The brain-cavity of the Uintatherium is perhaps the most re- 
markable feature in this remarkable genus. It shows us that the 
brain was proportionately smaller than in any other known mam- 
mal, recent or fossil, and even less than in some reptiles. It is, in 
fact, the most reptilian brain in any known mammal. In U. mira- 
bile (one of the large- tusked, horned species) it could apparently 
have been drawn through the neural canal of all the presacral 
vertebrae." "^ 

It was, in fact, a small oval mass of about the same diameter 
as the spinal cord ! 

One other strange form which may belong to the earliest 
ungulates has been found in the Upper Eocene of Egypt, and 
forms a new suborder, Barjpoda. It is known from a very 
complete skull (Fig. 76), which is remarkable for the very 
regular set of teeth, as well as for the wonderful horn-cores, 
two small at the back and two enormous ones projecting in 
front. The skull is nearly 3 feet long, and the larger horn- 
cores about 2% feet ; and as these certainly carried true horns 
they probably surpassed any of the Dinocerata. Large quan- 
tities of detached bones have also been obtained, sufficient to 
show that the creature was an ungulate of elephantine dimen- 
sions and altogether unique in appearance. This creature hail 
a somewhat larsjer brain thnn the great American ungulates, 



240 



THE WORLD OF LIFE 



and has affinities with a curious little existing animal, the 
hyrax. 




Fig. 76. — Skull of Arsinoitherium zitteli. 
From the Upper Eocene of the Fayoum, Egypt. One-twelfth nat. size. 

(B.M. Guide.) 



Order — Camivora 

These can also be traced back to middle or late Eocene 
times both in l^orth America and Europe. They were mod- 
erate-sized animals, forming a distinct sub-order, Creodonta, 
the skeleton of one of which is shown in Fisr. 77. Thev had 
flesh-eating teeth, but more like those of the carnivorous mar- 
supials of Australia than of our living carnivores, with a type 
of skeleton showing considerable litrhtness and activity. Some 
of the species were as large as lions. 



LIFE OF TERTIAEY PERIOD 241 

Some of the older remains in South America, called Sparas- 
sodonta, are believed to belong to the same or an allied sub- 
order. They occur in beds of Lower Miocene age in Pata- 
gonia ; and Mr. Lydekker holds them to be " undoubtedly 
marsupials," allied to the Dasyuridic of Australia. One of 
these has been named Prothylacinus, from the resemblance of 
its jaw to that of the Tasmanian wolf (Thylacinus australis). 
Other small species forming a distinct family, Microbiothe- 
ridie, he also thinks were probably " minute polyprodont mar- 
supials of Australian type." ^ 

In the later (upper) beds of the Eocene formation and the 
early or middle Miocene, ancestral forms of many of our Mam- 
malia have been found both in Europe and Xorth America ; 
but these are so numerous, and their affinities in some cases 
so obscure, that only a few of the prominent examples need 
be given. One of these, whose skeleton is figured on page 243, 
belongs to the family Anthracotheridae, which has affinities 
with the pigs and the hippopotami, of which it seems to be 
an ancestral form. The fossil remains of this group are found 
in deposits of middle Tertiary age all over the northern hemi- 
sphere. They have two, three, or four separate toes, and teeth 
much like those of swine. 

Another family, the Anoplotheridae, contains a variety of 
animals w^hich seem to be ancestral forms of the ruminants. 
The genus Anoplotherium (Fig. 79) was one of the most re- 
markable of these in having a full and continuous set of teeth 
without any gaps, like that of the Arsinoitherium already 
figured. 

1 Geog. Hist, of Mammals, pp. 111-112. From these facts and otliers re- 
ferred to in my preceding chapter, Mr. Lydekker thinks that " it is difficnlt 
to come to any other conclusion than that the ancestors of the Santa Crucian 
polyprotodont marsupials reached the country either by way of the Antarc- 
tic continent or by a land-bridge in a more northern part of the Pacific." 
To avoid a break of connection in the present exposition, I have briefly 
stated some of the difTieuliies in the way of such a theory in an Ap- 
pendix to this chapter. Those who wish to see the whole subject of the 
" Permanence of Oceanic and Continental Areas " more fully discussed are 
referred to my volumes on Darwinism and Island Life. 



242 



THE WORLD OF LIFE 



An allied family, Oreodontidse, somewhat nearer to rumi- 
nants, but with four-toed feet, were very abundant in Xorth 
America in Miocene times. They were remotely allied to 




deer and camels, and were called by Dr. L-eidy " ruminating 
hogs." They seem to have occupied the place of all these 



LIFE OF TEKTIAEY PEEIOD 



243 




animals, six genera and over twenty species havlnp: lieen de- 
scribed, some of which survived till the earlv Pliocene. 

The family Pala^otheridnc was also abundant during tho 



244 



THE WORLD OF LIFE 



same period in Europe, and less so in !N"orth America. As 
shown in the restoration in Fig. 80, it somewhat resembled 
the tapir; but other genera are more like horses, and show a 
series of gradations in the feet towards those of the horse- 
tribe, as shown bj Hnxley's figures reproduced in my Dar^vin- 



ism. 



The Origin of Elephants 

Till quite recently one of the unsolved problems of palaeon- 
tology was how to explain the development of the Proboscidea 
or elephant tribe from other hoofed animals. Hitherto extinct 
species of these huge beasts had been found in a fossil state 
as far back as the Miocene (or middle Tertiary) in various 
parts of Europe, Asia, and Xorth America ; one species, the 
mammoth, being found ice-preserved in Arctic Siberia in great 
quantities. Some of these w^ere somewhat larger than existing 
elephants, and several had enormously large or strangely curved 
tusks; but, with the exception of Dinotherium, which had 
the lower jaw and tusks bent downwards, and Tetrabelodon, 
with elongated jaws and nearly straight tusks, none were very 
different from the living types and gave no clue to their line 
of descent. But less than ten years ago a number of fossils 
have been obtained from the middle and higher Eocene beds 
of the Fayoum district of Egypt, which give the long-hoped-for 
missing link connecting the elephants with other ungulates. 

The most primi- 
tive form now discov- 
ered was about the 
size of a very large 
dog, and its skull 
does not differ very 
strikin2:lv from those 
of other primitive 
ungulates. It has, 
Fig. 81. — Skull of Moeritherium lyonsi. however some slie'ht 
From the Middle Eocene cf the Fayoum, Egypt. One- , . '. . , ^ , 

seventh nat. size. (B.M. Guide.) peculiarities whlch 





Fig. 7!). — Anoplotherium commn/tie. 

Upper Eocene (Paris; also at Binstead, Isle of Wight.) From Nicholson's 

Palaeontology.) 

This animal was about the size of an ass, and was especially remarkable fur its 
continuous set of 44 teeth, there being no gap in the series. No livins mammal 
except man has this characteristic. It is supposed to have been a highly spe- 
cialized enrly type which has left no direct descendants. 







Fj(;. 80. — /'(ilaotherium ntogntini. 
from the Upper Eocene of Paris and the Isle of "Wight. (Nicholson's PahuDntology.) 

The numerous species of Pala?otlierium were three-toed animals bavins resembbmces 
to horses, tapirs, and llamas. The species here figured (as restored by Cuvier) 
was about the size of a horse, but it is now known that the neck was consid- 
erably longer than here shown. 



LIFE OF TEETIARY PERIOD 245 

show a connection with the Proboscidea. These are that the 
nasal opening is near the end of the snout, indicating, prohably, 
the rudiment of a proboscis; the back of the skull is also thick- 
ened and contains small air-chambers, the first step towards the 
very large air-chambers of the elephant's skull, whose purpose is 
to afford sufficient surface for the powerful muscles which sup- 
port the weight of the tusks and trunk. The teeth show two 
short tusks in front in the upper jaw in the same position as the 
tusks of elephants, while the lower jaw or chin is lengthened 
out and has two incisor teeth projecting forward. The molar 
teeth show the beginning of the special characters which dis- 
tinguish the huge grinding teeth of the elephants. This crea- 
ture was named MoerWierium lyonsi; and its remains have 
been found in great abundance along with those of both land 
and sea animals, shoAving that they were deposited in what 
was then the estuary of the ISTile, though now far inland. 

Somewhat later, in the Upper Eocene, another group of 
animals, the Palseomastodons, have been found, showing a con- 
siderable advance (see Diagram, Fig. 82). They vary in size 
from a little larger than the preceding to that of a small ele- 
phant. The skull is very much modified in the direction of 
some of the later forms. After these come the Tetrabelodons 
from the Miocene beds of France and North America, and the 
Pliocene of Germany. These w^ere more like elephants in 
their general form, though their greatly elongated lower jaw, 
bearing incisor teeth, seem to be developing in another direc- 
tion. In Tetrahelodon longirostris, however, we see the lower 
jaw shortened and the incisor teeth greatly reduced in size; 
thus leading on to the true elephants, in which these teeth 
disappear. 

The skeleton of Tetrahelodon angustidens shows the lower 
tusks sliorter than the upper ones, but in the fine specimen 
moimted in the Paris Museum, and photographed in Sir Ray 
Lankester's Extinct Animals, both are of the same h^igth, 
and the upper pair curve slightly (hnvnwards on each side of 
the lower pair; and they are thus shown in the suggested 



246 



THE WOKLD OF LIFE 



Recenl 

Pleistocene ELE PHA3 

( short chinj 
Ufiper Pliocene 




Lower Pliocene 
Upjier Miocene 



TETRABELODON 

[LONGIROSTRrS STACE] 



(shortening chinj 




Middle Miocene TETRABELODON 

fANCUSTTDENS STAGE] 

lower Miocene (long chinj 



l/frper Oligocene 




Migration from Africa 
into EuTvp.e -Asia 



Imer Oligocene? 
Upfier Eocene 
MiddleBocene 
Lower Eocene 



PALAEOMASTODON 
^lengthening chinj 

MOERlTHEKrUM 
(short chin) 





Fig. 82. — Diagrams showing Increase of Size and Alteration in Form of 
Skull and Teeth of the Proboscidea since Eocene Time. (B.M. Guide.) 




Fig. 83. — Skeleton of Tetrahelodon luigustidens. 
From the Middle Eocene of Sansaus, France. (B.M. Guide.) 



4 



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i 



A 



.;■ V 



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Fig. 84. — Probable Appearance of Tetrahelodon (HKjustidens. 
/From Sir Ray Lankester's Extinct Animals.) 



LIFE OF TERTIARY PERIOD 



247 



appearance of the living animal, here reproduced from his book. 
(Fig. 84.) The trunk could not therefore have hung down 
as in the modern elephants, and it seems hardly likely that 
with such tusks a trunk would have been developed. If a short 
one had been formed it would probably have been for the 
purpose of drinking and for pushing food into the mouth side- 
ways. It is most interesting to see how the difficulty was 




Fig. 85. — Skeleton of Mastodon Americanus. 
From the Pleistocene of Missouri, U.S.A. Length, 20 feet; height, 9% feet. 

(B.M. Guide.) 

overcome. In the next stage both pairs of tusks have become 
straightened out, the lower ones much reduced in length and 
the chin also somewhat shortened. That this process went on 
step by step is indicated by the ^lastodons, which are elephants 
with a simpler form of teeth, and a pair of tusks like all living 
and recently extinct elephants (see Fig. 85). But when very 
young the American Mastodon had a pair of short tusks in the 
lower jaw, which soon fell out. In the character of its teeth 
generally, the Mastodon agrees with Tetrabelodon (wliich was 
originally classed as a Mastodon) ; and there are Indian extinct 



248 THE WORLD OF LIFE 

species which show other stages in the reduction of the lower 
jaw. 

We have here, therefore, a most remarkable and very rare 
phenomenon, in which we are able to see progressive evolution 
upon what seems to be a wrong track which, if carried further, 
might be disastrous. Usually, in such cases, the too much 
developed or injuriously developed form simply dies out, and 
its place is supplied by some lower or less modified species which 
can be more easily moulded in the right direction. But here 
(owing probably to some exceptionally favourable conditions), 
after first lengthening both lower jaw and lower tusks to keep 
pace with the upper ones, a reversal of the process occurs, 
reducing first the lower tusks, then the lower jaw, till these 
tusks completely disappeared and the lower jaw was reduced 
to the most useful dimensions in co-ordination with a greatly 
lengthened and more powerful trunk. Although in this case 
the gaps are still rather large, there can be no doubt that we 
have here obtained a view of the line of development of the 
most remarkable land mammals now living from a small gen- 
eralised ungulate mammal, as indisputable and as striking as 
that of the horses from the little five-toed Eohippus of the 
American Eocene. 

It may be here mentioned that the huge American Mas- 
todon has been found in the same deposits with stone arrow- 
heads, and was undoubtedly hunted by early man; as was also 
the huge mammoth whose beautifully curved tusks form its 
chief distinction from the living Indian elephant (Eig. 86). 
This species is abundant in the frozen mud at the mouths 
of the Siberian rivers; and in some cases the whole body is 
preserved entire, as in an ice-house, and the flesh has been 
sometimes roasted and eaten by the natives. Remains of 
skeletons have been found in our own country and over a large 
part of Northern Europe and Asia ; while its portrait has been 
drawn from life by prehistoric man, either upon the tusks 
themselves or upon the flat portions of the horns of reindeer 
which he hunted for food. 



LIFE OF TERTIAEY PERIOD 



249 




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Tertiary Mammals of South America and Australia 



ISTo part of the world has so many distinct groups of !Mam- 
malia peculiar to it as South America, among wliioh the most 
remarkable are the sloths and the armadillos; and all of tlicm 
are found fossil in the middle or late Tertiary or the Pleisto- 
cene, from Brazil to Patagonia, and are often represented by 
strange forms of gigantic size. Some account of these will now 
be given. DarAvin was one of the first collectors of these 
fossils on his voyage in the Beagle, and during the la:^t twenty 



250 



THE WOKLD OF LIFE 




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or tliirty years niimerous travellers and residents, especially 
in Argentina, have more thoroughly explored the deposits of 



LIFE OF TERTIAKY PEFaOD 251 

the pampas of various ages. Their great richness and im- 
portance may be indicated by the following enumeration of 
the chief orders of Mammalia represented in them. 

Of the Peimates (or monkeys) all the remains are of the 
peculiar American families Cebidas and Ilapalida:', with one 
extinct genus of the fonner. Bats (the order Chiroptera) are 
abundant, with several peculiar genera. The Insectivora arc 
very rare in South America, but a fossil has been found sup- 
posed to belong to the peculiar West Indian family Solenodon- 
tidge. The Carnivora are chiefly represented by fossils of the 
American family Procyonidse (comprising the racoons and 
coati-mundis), of which several extinct genera have been ol>- 
tained. The hoofed animals (Ungulata), which, from tlieir 
great abundance in a living state in every part of the world, 
and their habit of living together in great herds often of many 
thousands, have been most frequently preserved in a fossil 
state, are here represented not only by all the chief forms that 
still inhabit the country, but also by some which are now 
only found in other continents, as well as by many which arc 
altogether extinct. Among the former the most interesting 
are true horses of the genus Equus, as well as two peculiar 
genera of ancestral Equidge, distinct from those so abundant 
in I^orth America. There are also several ancestral forms 
of the Llama tribe, one of which, Macraiichenia patacJionica, 
was as large as a camel; and there are others so distinct as to 
form a separate family Proterotheriidse. 

Another sub-order, Astrapotheria, were more massive ani- 
mals, some of which equalled the rhinoceros in size. They 
consist of two distinct genera, only found in the Patagouian 
deposits of Mid-Tertiary age.-^ 

Still more remarkable is another group — the Toxodontia — 
sometimes exceeding the rhinoceros in bulk, but with teeth 
which approached those of the Rodentia; of these there are 
various forms, which are grouped in three distinct families. 
The skeleton of one of the most remarkable of this group is 

iLydekker's Geographical History of Mammals, p. 81. 



252 THE WOELD OF LIFE 

shown in Fig. 87. Yet another distinct sub-order, Pyrotheria, 
which in its teeth somewhat resembled the extinct European 
Dinotherium, and which had a large pair of tusks in the lower 
jaw is found in the earlier Tertiary strata of Santa Cruz in 
Patagonia. The elephants also had a representative among 
these strange monsters in the form of a species of Mastodon, 
a genus also found in North America. 

The very numerous and peculiar South American rodents 
commonly called cavies, including the familiar gniinea-pig, are 
well represented among these fossils, and there are many ex- 
tinct forms. Most of these are of moderate size, but one, 
Megamys, said to be allied to the viscachas, is far larger than 
any living rodent, about equalling an ox in size. 

Perhaps more remarkable than any of the preceding are 
the extinct Edei^tata which abound in all these deposits. The 
entire order is peculiar to America, with the exception of the 
scaly ant-eater of Asia and the aard-vark of South Africa, and 
there is some doubt whether these last really belong to the same 
order. The living American edentates comprise three fam- 
ilies, generally known as sloths, ant-eaters, and armadillos, 
each forming a well-marked group and all with a fair number 
of distinct species. But besides these, two extinct families 
are known, the Glyptodontidse and the Megatheriidse, the 
former being giant armadillos, the latter equally gigantic ter- 
restrial sloths. Both of these lived from the Miocene period 
almost to our own time, and they are especially abundant in 
Pliocene and Pleistocene deposits. Some of the extinct forms 
of armadillo were very much larger than any now living; but 
it is among the Glyptodonts, which had a continuous shield 
over the whole body, that the largest species occurred, the shell 
being often 6 or 8 feet long. The skeleton of one of these is 
represented by Fig. 88. One of the most recent (Dsedicurus) 
was 12 feet long, of which 5 feet consisted of the massive 
armoured tail, which latter is believed to have borne a number 
of movable horns. The earlier fossil species were of much 
smaller size, and, though far more abundant in the south, a 



LIFE OF TEETIARY PERIOD 






few of them have been found in the Pliocene deposits of Texas. 
The extinct ground-sloths arc even more remarkable, since 




254 THE WORLD OF LIFE 

they were intermediate in structure between the living sloths 
and the ant-eaters, but adapted for a different mode of life. 
Almost all are of large, and many of gigantic size. The Mega- 
therium, which was discovered more than a century ago, was one 
of the largest, the skeleton (represented by a cast in the British 
Museum) being 18 feet long. Their massive bones show enor- 
mous strength, and they no doubt were able to uproot trees, 
by standing erect on the huge spreading hind feet and grasping 
the stem with their powerful arms, in order, to feed upon the 
foliage, as shown in the illustration (Fig. 89). The jaw-bones 
are lengthened out, indicating extended lips and probably a 
prehensile tongue with which they could strip off the leaves. 
An allied genus, Mylodon, which is somewhat smaller, has 
been found also in Kentucky in beds of the same age, the 
Pleistocene. 

What renders these creatures so interesting is that they sur- 
vived till a very recent period, and that they were contemporary 
with man. Both human bones and stone implements have 
been found in such close association with the bones or skele- 
tons of these extinct sloths that they have been long held to 
have lived together. But a more complete proof of this was 
obtained in 1897. In a cavern in Patagonia, in a dry powdery 
deposit on the floor, many broken bones of a species of Mylodon 
were found ; and also several pieces of skin of the same animal 
showing marks of tools. Bpnes of many other extinct animals 
were found there, as well as implements of stone and bone, 
remains of fires, and bones of man himself. Among the other 
animal remains were those of an extinct ancestral horse, and 
on some of the bones there were found shrivelled remains of 
sinews and flesh. 

Allied forms are found in older deposits, as far back as the 
Miocene, but these are all of smaller size. They probably 
ranged all over South America, and the two genera Megathe- 
rium and Mylodon occur also in the most recent deposits of 
the southern United States. The numerous skeletons in the 
pampas of Argentina are usually found on the borders of old 




Fig. 89. — Probable Appearance of the (iiant Ground-Sloth 
( Megatherium gigan icnui ) . 

As large as an elephant. Found in the Pleistocene gravels of South America 
(From Sir Ray Lankester's Extinct Animals, p. 172.) 




Vic. 'JU. — MyUxlon robust ufi. 
From the Pleistocene of South America. ( Nicholson s Palii'ontohtpy. ) 



J 



J 



LIFE OF TERTIARY PERIOD 255 

lakes and rivers, in the positions in which they died. Thrv 
are supposed to have perished in the mud or quagmires whih- 




o 



3 
o 



^ to 



'y 05 

o 2 



^ 



o 



til ^ 

o 






o 






O ja 

c a> 

.2 -S 
3 



c: 

2 a 



S 



attempting to reach the water for drink during dry seasons, 
great droughts being prevalent in the district; but when these 



256 THE WOKLD OF LIFE 

large animals lived there must have been much more woody 
vegetation than there is now. During the voyage of the Beagle, 
Darwin collected a large quantity of these interesting fossils, 
as described in his JSTaturalist's Voyage round the World (chap, 
v.). The skeleton and outline figure of a Mylodon shown in 
Fig. 90 was 11 feet in total length, but other species were 
larger. 

A remarkable extinct genus, Scelidotherium, of which the 
complete skeleton is shown in Fig. 91, was about 10 feet long, 
and has less massive limbs than the Megatherium or Mylodon, 
and more elongated jaws. In some respects it approached the 
ant-eaters, and was probably, like them, terrestrial in its habits. 
About twelve distinct genera of these ground-sloths are now 
known, comprising a large number of species. They ranged 
all over South America and into the warmer parts of North 
America, and before the immigration of the horse and the 
sabre-toothed tiger in Pleistocene times, they must have con- 
stituted the larger and more important portion of the mam- 
malian fauna of South America. 

Extinct Mammals of Australia 

The existing Australian mammals, although of varied form 
and structure, are almost all marsupials, the only exceptions 
being the aerial bats, and small rodents allied to rats, which 
latter might have entered the country by means of floating 
timber or trees from the nearest islands. These two orders 
are therefore of little importance geographically, although by 
counting the species it may be made to appear that the 
higher mammals (Placentalia) are nearly as numerous as the 
lower (Marsupialia). The wild dog, or dingo, is also appar- 
ently indigenous, but it may have been introduced by early 
man, as may some of the rodents. It is unfortunate that the 
deposits of Tertiary age in Australia seem to be very scanty, 
except recent gravels and alluvial muds, and none of these 
have produced fossils of Mammalia except in caves and dried- 
up lakes, which are all classed as of Pleistocene age. These, 



LIFE OF TERTIARY PERIOD 



2:.7 



however, are very productive in animal remains wliidi arc 
extremely interesting. 

They consist of many living species, but with them numljers 
of extinct forms, some of gigantic size, but all undoul)t(Mlly 
allied to those living in Australia to-day. Thus, bones of 
kangaroos are found ranging in size from that of the smallest 
living species np to that of a donkey, and sometimes of verv 
distinct forms and proportions. But with theso have been 
found a huge wombat, the size of a large rhinoceros, of which 
the skull is here represented (Fig. 92). The complete skele- 




FiG. 92. — Skull of an Extinct Marsupial, Diprotodon australis. 
From the Pleistocene of Queensland and South Australia. With a man's skull, to 

show comparative size. (B.M. Guide.) 



ton has been quite recently obtained from Lake Callabonna in 
South Australia. It is found to be 12 feet long measured 
along the vertebrae, and 6 feet 2% inches high. As it has been 
found in various parts of the continent, it was probably abun- 
dant. Another smaller animal of somewhat similar form 
was the Xototherium, which was found in Queensland, to- 
gether with the Diprotodon, about fifty years ago. A large 
phalanger was also found, which Professor Owen called the 
pouched lion {Tliylacoho carnifex), but it is doubtful whether 



258 THE WORLD OF LIFE 

it was carnivorous (see Fig. 93). True carnivorous mar- 
supials allied to the ^' Tasmanian wolf" (Thylacinus) and the 
Tasmanian devil {Sarcopliilus) are also found. 




Fig. 93. — Skull of Thylacoleo carnifex. 
From the Pleistocene of Australia. One-fifth nat. size. (B.M. Guide.) 



How and when the marsupials first entered Australia has 
always been a puzzle to biologists, because the only non-Aus- 
tralian family, the opossums, are not closely allied to any of 
the Australian forms, and it is the opossums only which have 
been found in tlie European early Tertiaries. But recent dis- 
coveries in South America have at length thrown some light 
on the question, since the Santa Cruz beds of Patagonia (Mid- 
dle Tertiary) have produced several animals whose teeth so 
closely resemble those of the Tasmanian Thylacinus that Mr. 
Lydekker has no doubt about their being true marsupials allied 
to the Dasvurid^e. There is also, in the same beds, another 
distinct f amilv of small mammals — the Microbiotheridge of 
Dr. Ameghino — which, from a careful study of their denti- 
tion, are also considered by Mr. Lydekker to be " polypro- 
todont marsupials of an Australian type." ^ 

But even more important is the discovery of living mar- 
supials of the Australian rather than the American type in the 
very heart of the South American fauna. In 1863 a small 
mouse-like animal of doubtful affinities was captured in Ecua- 

lA Geographical Historj^ of Mammals, p. 109. 



LIFE OF TERTIARY PERIOD 259 

dor. But in 1895 a larger species of the same genus was 
obtained from Bogota; and it was then seen that they be- 
longed to a group of which large numbers of fossil remains 
had been found in the Santa Cruz beds. By a comparison 
of these remains of various allied forms with the specimens 
of those now living, it seems no longer possible to doubt that 
marsupials of Australian type have existed in South America 
in Middle or Late Tertiary times, and tiiat some of them 
survive to-day in the equatorial Andes, where their small size 
has probably saved them from extinction. Of these latter, 
Mr. Lydekker says: "In the skeleton the lower jaw exhibits 
the usual inflexion of the angle ; and the pelvis carries 
marsupial bones. A small pouch is present in the female." 
These small marsupials have been named Csenolestes, while 
their fossil allies are so numerous and varied that they have 
to be classed in three families — Abderitidae, Epanorthidse, 
and Garzoniidae. This is only mentioned here to show the 
large quantity of materials upon which these conclusions are 
founded. 

Teachings of Pleistocene Mammalia 

For the purpose of the present work it is not necessary to 
go into further details as to the development of the higher 
forms of life, except to call attention to some other cases of 
the sudden dying out of great numbers of the more developed 
species or groups during the most recent geological period — 
the Pleistocene. 

It has already been shown how, in temperate South 
America, the huge sloths and armadillos, the giant llamas, 
the strange Toxodontia, and the early forms of horses all 
disappeared at a comparatively recent epoch. In Xorth 
America a similar phenomenon occurred. Two extinct lions; 
a number of racoons and allied forms, including several ex- 
tinct genera; six extinct species of horses; two tapirs; two 
genera of peccaries ; a llama and a camel ; several extinct 
bisons, sheep, and deer; two elephants and two mastodons, 



260 THE WORLD OF LIFE 

and four genera of tlie wonderful terrestrial slotlis, ranged 
over the whole country as far north as Oregon and the Great 
Lakes in quite recent times; while four genera of the great 
ground-sloths have been found as far north as Pennsylvania. 

This remarkable assemblage of large Mammalia at a period 
so recent as to be coeval with that of man, is most extraor- 
dinary; while that the whole series should have disappeared 
before historical times is considered by most geologists to be 
almost mysterious. At an earlier period, especially during 
the Miocene (Middle Tertiary), Xorth America was also 
wonderfully rich in Mammalia, including not only the ancestors 
of existing types, but many now quite extinct. At this time 
there were several kinds of monkevs allied to South American 
forms; numerous extinct Carnivora, including the great sabre- 
toothed tiger, Machserodus; several ancestral horses, includ- 
ing the European Anchitherium ; several ancestral rhinoceroses, 
the huge horned Brontotheriidae, the Oreodontidse, and many 
ancestral swine. Almost all these became extinct at the end 
of the Miocene age. "^ 

In Europe we find very similar phenomena. During the 
Pleistocene age, the great Irish elk, the cave-lion and the 
sabre-toothed tiger, cave-bears and hyaenas, rhinoceroses, 
hippopotami and elephants, extinct species of deer, antelopes, 
sheep and cattle, were abundant over a large part of Europe 
(many even reaching our own country), and rapidly became 
extinct; and what renders this more difficult to explain is, 
that all of these and many others, with numerous ancestral 
forms, had inhabited Europe throughout the Pliocene and 
some even in Miocene times. 

These very interesting changes in the northern hemisphere 
are paralleled and completed in far-distant Australia. In 
caves and surface deposits of recent formation a whole series 
of fossil remains have been found, all of the marsupial order, 
and most of them of extinct species and even extinct genera. 
But what is more extraordinarv is, that several of them were 
larger than any now living, while some were as gigantic as 



LIFE OF TERTIARY PERIOD 201 

the huge gi'ound-sloths and armadillos of the Pampas. There 
were numerous kangaroos, some much lar<Ter than any liv- 
ing, including species allied to the tree-kangaroos of New 
Guinea; a Phascolomjs (wombat) as large as a donkey; the 
Diprotodon, a thick-limbed animal nearly as large as an 
elephant, but allied both to the kangaroos and the phalangor>. 
Equally remarkable was the Tliylacoleo carnifex, nearly as 
large as a lion and with remarkable teeth (Fig. 03, p. 258). 
The very peculiar Xototherium, allied to the wombats, was 
nearly as large as a rhinoceros; and several others imperfectly 
known indicate that they were of larger size than their nearest 
living allies. 

A number of very similar facts are presented by recently 
extinct birds. The Moas of ^ew Zealand were of various 
sizes, but the largest was 8% feet high when standing natu- 
rally, but when raising its body and neck to the fullest extent 
it would have perhaps reached to a height of 12 feet. 

In Madagascar also there was a huge bird, the ^pyornis, 
which was probably larger than the largest of the Moas, and 
whose egg, frequently found in sand-hills, sometimes measures 
3 feet by 2% feet in circumference, and will hold more than 
two gallons. It is almost certain that these huge birds were 
all coeval with early man, and in the case of the Moas this 
has been completely proved by finding their bones in ancient 
native cooking ovens. It is probable, therefore, that their 
final extinction was due to human agency. 

Probable Cause of Extinction of the Pleistocejie Mammalia 

The complete extinction of many of the largest Mammalia, 
which were abundant in almost all parts of the world in 
Pleistocene times, has not yet received a wholly satisfactory 
explanation. The fact that the phenomenon is so near to 
our own era renders it more striking than similar occurrences 
in remote ages. With the one exception of the glacial e]><^ch, 
there has been very little modification of tlie earth's surface 
since the close of the Tertiary era ; and in several cases species 



262 THE WORLD OF LIFE 

which iindo"abtedly survived that event have since become ex- 
tinct. This great climatic catastrophe did nndoubtedly pro- 
duce extensive migration of Mammalia ; but, owing to the fact 
that the ice-sheet had very definite limits, and that numbers 
of large mammals were merely driven southward, it is not 
held to be a sufficient cause for so general a destruction of the 
larger forms of life. 

Another circumstance that puts the glacial epoch out of 
court as a sufficient explanation of the widespread extinction 
is that in two very remote parts of the earth, both enjoying 
a warm or even a sub-tropical climate — x\ustralia on the one 
hand, and Brazil to Argentina on the other, — exactly the 
same phenomena have occurred, and, so far as all the geo- 
logical evidence shows, within the same general limits of time. 

It is no doubt the case that at each of the dividing lines 
of the Tertiary era — that is, in passing from the Eocene to 
the Miocene, or from the latter to the Pliocene, and thence 
to the Pleistocene — many large Mammalia have also become 
extinct. But in these cases a much greater lapse of time can 
be assumed, as well as larger changes in the physical condi- 
tions, such as extension of land or water, climate, vegetation, 
etc., which, combined with the special disabilities of very 
large animals, are sufficient to account for the facts. It may 
be well here to state again the causes which lead to the ex- 
tinction of largo animals rather than small ones, as given 
in my Darwinism (p. 394) more than twenty years ago, and 
also in my Geographical Distribution of Animals, i. p. 157 
(1876): 

" In the first place, animals of great bulk require a proportionate 
supply of food, and any adverse change of conditions would affect 
them more seriously than it would affect smaller animals. In the 
next place, the extreme specialisation of many of these large animals 
would render it less easy for them to become modified in any new 
direction required by the changed conditions. Still more impor- 
tant, perhaps, is the fact that very large animals always increase 
slowly as compared with small ones — the elephant producing a 



LIFE OF TERTIARY PERIOD 203 

single young one every three years, while a rahbit may have a litter 
of seven or eight young two or three times a year. Now the prob- 
ability of useful variations will be in direct proportion to the popu- 
lation of the species, and, as the smaller animals are not only many 
hundred times more numerous than the largest, but also increase 
perhaps a hundred times as rapidly, they are able to become quickly 
modified by variation and natural selection, while the large and 
bulky species, being unable to vary quickly enough, are obliged to 
succumb in the struggle for existence/^ 

To these reasons we may add that very large animals arc 
less rapid in their motions, and thus less able to escape from 
enemies or from many kinds of danger. The late Professor 
O. Marsh, of Yale University, has well observed : 

" In every vigorous primitive type which was destined to survive 
many geological changes, there seems to have been a tendency to 
throw off lateral branches, which became highly specialised, and 
soon died out because they were unable to adapt themselves to new 
conditions. . . . The whole narrow path of the Suilline (hog) 
type, throughout the entire series of the American tertiaries, is 
strewn w4th the remains of such ambitious offshoots, manv of them 
attaining the size of a rhinoceros; while the typical pig, with an 
obstinacy never lost, has held on in spite of catastrophes and evolu- 
tion, and still lives in America to-day." 

We may also remember that it is still more widely spread 
over the Old World, under the various forms of the hojr-family 
(Suidse), than it is in America, under the closely allied 
peccary type (Dicotylida?). 

That this is a true cause of the more frequent passing away 
of the largest animal types in all geological epochs there can 
be no doubt, but it certainly will not alone explain the dying 
out of so many of the very largest ^Mammalia and birds dur- 
ing a period of such limited duration as is the Pleistocene 
(or Quaternary) age, and under conditions which were cer- 
tainly not very different from those under whicli they had 
been developed and had lived in many cases down to the 
historical period. 



264 THE WORLD OF LIFE 

What we are seeking for is a cause which has been in 
action over the whole earth during the period in question, 
and which was adequate to produce the observed result. 
AVhen the problem is stated in this way the answer is very 
obvious. It is, moreover, a solution which has often been 
suggested, though generally to be rejected as inadequate. It 
has been so with myself, but why I can hardly say. In his 
Antiquity of Man (4th ed., 1873, p. 418) Sir Charles Lyell 
says: 

^^ That the growing power of man may have lent its aid as the 
destroying cause of many Pleistocene species must, however, be 
granted; yet, before the introduction of fire-arms, or even the use 
of improved weapons of stone, it seems more wonderful that the 
aborigines were able to hold their own against the cave-lion, hyena, 
and wild bull, and to cope with such enemies, than that they failed 
to bring about their extinction.'' 

Looking at the whole subject again, with the much larger 
bodv of facts at our command, I am convinced that the above 
somewhat enigmatic passage really gives the clue to the whole 
problem, and that the rapidity of the extinction of so many 
large Mammalia is actually due to man's agency, acting in 
co-operation with those general causes w^hich at the culmina- 
tion of each geological era has led to the extinction of the 
larger, the most specialised, or the most strangely modified 
forms. The reason why this has not been seen to be a suffi- 
cient explanation of the phenomena is, I think, due to two 
circumstances. Even since the fact of the antiquity of man 
w^as first accepted by European geologists only half a century 
ago, each fresh discovery tending to extend that antiquity has 
been met with the same incredulity and opposition as did 
the first discovery of flint weapons by Boucher de Perthes 
in the gTavels near Amiens. It has been thought necessary 
to minimise each fresh item of evidence, or in many cases to re- 
ject it altogether, on the plea of imperfect observation. Thus 
the full weight of the ever-accumulating facts has never been 



LIFE OF TERTIAKY TERIOD 265 

adequately recognised, because each new writer has Weu afraid 
to incur the stigma of credulity, and therefore usually limited 
himself to such facts as he had himself observed, or could quote 
from his best-known contemporaries. On the other hand, the 
old idea that man was the latest product of nature (or of 
evolution) still makes itself felt in the attempt to escape from 
any evidence proving man's coexistence with such extinct 
species as would imply greater antiquity. In the chapter on 
The Antiquity of Man in l^orth America (in my Xatural 
Selection and Tropical !N'ature) I have given numerous ex- 
amples of both these states of mind. And what makes them 
so specially unreasonable is, that all evolutionists are satis- 
fied that the common ancestor of man and the anthropoid apes 
must date back to the Miocene, if not to the Eocene period ; 
so that the real mystery is, not that the works or the remains 
of ancestral man are found throughout the Pleistocene period, 
but that they are not also found throughout the Pliocene, and 
also in some Miocene deposits. There is not, as often as- 
sumed, one " missing link " to be discovered, but at least a 
score such links, adequately to fill the gap between man and 
apes ; and their non-discovery is now^ one of the strongest 
proofs of the imperfection of the geological record. 

When we find, as we do, that, with the one exception of 
Australia, proofs of man's coexistence with all the great ex- 
tinct Pleistocene Mammalia are sufiiciently clear, while that 
the Australians are equally ancient is proved by their form- 
ing so well-marked and unique a race, the fact that man should 
every^vhere have helped to exterminate the various hugo 
quadrupeds, whose flesh would be a highly valued food, al- 
most becomes a certainty. The following passage from one 
of our best authorities, Mr. R. Lydekker, F.K.S., puts the 
w^hole case in a very clear light, though he does not definitely 
accept the conclusion whicli I hold to be now well established. 
He says: 

" From the northern half of the Old World have disappeared the 
mammoth, the elasmothere (a very peculiar, huge rhinoceros, whose 



266 THE WORLD OP LIFE 

skull was more than three feet long), the woolly and other rhino- 
ceroses, the sabre-toothed tigers, etc.; North America has lost the 
megalonyx and the Ohio mastodon; from South America, the 
glyptodonts, mylodons, the megalothere, and the macrauchenia 
have been swept away; while Australia no longer possesses the 
diprotodon and various gigantic species of kangaroos and wombats. 
In the northern hemisphere this impoverishment of the fauna has 
been very generally attributed to the effects of the glacial period, 
but, although this may have been a partial cause, it can hardly be 
the only one. The mammoth, for instance, certainly lived during 
a considerable portion of the glacial epoch, and if it survived thus 
far, why should it disappear at the close? Moreover, all the Eu- 
ropean mastodons and the southern elephant {Elephas meridionalis) 
died out before the incoming of glacial conditions; and the same 
is true of all the extinct elephants and mastodons of Southern 
Asia. Further, a large number of English geologists believe the 
brick earths of the Thames valley, which contain remains of rhino- 
ceroses and elephants in abundance, to be of post-glacial age. As 
regards the southern hemisphere, it can hardly be contended that 
glacial conditions prevailed there at the same time as in the north- 
ern half of the world. 

" It is thus evident that, though a very great number of large 
mammals were exterminated (perhaps partly by the aid of human 
agency) at the close of the Pleistocene period, when the group had 
attained its maximum development as regards the bodily size of its 
members, yet other large forms had been steadily dying out in 
previous epochs. And it would seem that there must be some 
general, deep-seated cause affecting the life of a species with which 
we are at present unacquainted. Indeed, as there is a term to the 
life of an individual, what is more natural than that there should 
also be one to the existence of a species. It still remains indeed, 
to account for the fact that the larger Pleistocene mammals had 
no successors in the greater part of the world, but perhaps, is in 
some way connected with the advent of man." ^ 

It is sometimes thought that early man, with onlv the rudest 
weapons, would be powerless against large and often well- 

1 A Geographical History of Mammals, R. Lydekker, B.A., F.R.S., V.P.G.S. 
etc., 1896, p. 18. 



LIFE OF TEKTIAEY PERIOD 267 

armed mammals. But this, I think, is quite a mistake. Xo 
weapon is more effective for this purpose than a spear, of 
various kinds, when large numbers of hunters attack a single 
animal; and when made of tough wood, with the point hard- 
ened by fire and well sharpened, it is as effective as when 
metal heads are used. Bamboo, too, abundant in almost all 
warm countries, forms a very deadly spear when cut obliquely 
at the point. The way in which even a man-eating tiger is 
killed by this means in Java is described in my ^lalay 
Archipelago (p. 82). Such a method would doubtless have 
been adopted even by Palaeolithic man, and would have been 
effective against any of the larger animals of the Pleistocene 
age. 

It is therefore certain, that, so soon as man possessed 
weapons and the use of fire, his power of intelligent com- 
bination would have rendered him fully able to kill or cap- 
ture any animal that has ever lived upon the earth ; and as 
the flesh, bones, hair, horns, or skins would have been of 
use to him, he would certainly have done so even had he 
not the additional incentive that in many cases the animals 
were destructive to his crops or dangerous to his children or 
to himself. The numbers he would be able to destroy, es- 
pecially of the young, would be an important factor in the 
extermination of many of the larger species. 

There remains, however, the question, well put by Mr. 
Lydekker, whether there is not some general deep-seated cause 
affecting the life of species, and sending to explain, if only 
partially, the successive dying out of numbers of large ani- 
mals involving a complete change in the preponderant typos 
of organic life at certain epochs; and to this question and 
some others allied to it a separate chapter must be devoted. 

APPEXDIX 

THE THEORY OF COXTINEXTAL EXTEXSIOXS 

Most writers consider that the preceding facts (see p. 2-11) go to 
prove the existence of a land-connection l)otwecn Soiitli America 



268 THE WORLD OF LIFE 

and Australia in Early or Middle Tertiary times. This, however, 
seems to me to be highly improbable for reasons given at full in my 
Island Life. Its supposed necessity depends on the assumption 
that the geological record is fairly complete, even as regards these 
small mammals, and that their not being yet discovered in the 
northern continents proves that they never existed there. But the 
extreme rarity of the small Secondary Mammalia, though they have 
been found scattered over the whole northern hemisphere, and the 
limited area in South America in which these Tertiary marsupials 
have been found, taken in connection with the enormous areas of 
geologically unexplored land in Asia and Australia, should make us 
very cautious in assuming such vast and physically improbable 
changes of land and sea at such a comparatively recent epoch. 
The theory of land-connection also introduces enormous difficulties 
of various kinds which it is well briefly to consider. If we suppose 
an absolute land-connection in order to allow the marsupial type to 
have entered Australia from temperate South America, we have 
to face the incredible fact, that of the whole varied mammalian 
fauna of the latter country this one group only was transmitted. 
In these same deposits there are found ancestral hoofed animals of 
small size (Pyrotherium) ; numerous rodents allied to cavies and 
porcupines; a host of Edentata allied to sloths, ant-eaters, and 
armadillos. These, taken altogether, are many times more numer- 
ous than the marsupials; they were more varied in structure and 
mode of life; and it is almost incredible that not one representa- 
tive of these somewhat higher forms sliould have reached the new 
country, or having reached it should have all died out, while the 
inferior group alone survived. Then, again, we know that birds 
and insects must have abounded in South America at the same 
period, while the whole 7000 miles of connecting land must have 
been well clothed with vegetation to support the varied life that 
must have existed upon it during the period of immigration. Yet 
no indication of a direct transference or interchange of these nu- 
merous forms of life in any adequate amount is found in either 
Australia or South Temperate America. We can hardly suppose 
such an enormous extent of land to have been raised above the 
ocean; that it should have become sufficiently stocked with life to 
serve as a bridge (7000 miles long!), and that a few very small 
marsupials only should have crossed it; that it then sank as rap- 



LIFE OF TERTIARY PERIOD 261) 

idly as it had been formed; with the one result of slocking Aus- 
tralia with marsupials, while its other forms of life — plants, birds, 
insects, molluscs — show an unmistakable derivation from the 
Asiatic continent and islands. A careful examination ol' a large 
globe or South Polar map, with a consideration of the diagram of 
the proportionate height of land and depth of ocean at p. .315 of 
my Darwinism, together with the argument founded upon it, will, 
I think, convince my readers that difficulties in geographical dis- 
tribution cannot be satisfactorily explained by such wildly im- 
probable hypotheses. If the facts are carefully examined, it will 
be found, as I have shown for the supposed " Atlantis " and 
" Lemuria," that such hypothetical changes of sea and land always 
create more serious difficulties than those which they are supposed 
to explain. People never seem to consider what such an explana- 
tion really means. They never follow out in imagination, step by 
step, the formation of any such enormous connecting lands between 
existing continents in accordance with what we know of the rate 
of elevation and depression of land, and the corresponding organic 
changes that must ensue. They seem to forget that such a vast 
and complete change of position of sea and land is not really known 
ever to have occurred. 

Let us consider for a moment what the supposed land-connection 
between South America and Australia really implies. The distance 
is more than half as much again as the whole length of the South 
American continent, and 1000 miles farther than from Southamj)- 
ton to the Cape. This alone should surely give us pause. P)ut 
unless we go as far south as the Antarctic circle, the depth of the 
intervening ocean is about two miles; and until we get near Xew 
Zealand there is not a single intervening island. There are here 
none of the indications we expect to find of any geologically recent 
depression of land on a vast scale. Of course we may suppose the 
connection to have been along a great circle within ten degrees of 
the South Pole, but that will not greatly shorten the distance, 
while we have not a particle of evidence for such a vast ehange of 
climate in Mid-Tertiary times as w(nild be required to render such 
a route possible. But the mere physical dilhculties are equally 
great. All land elevation or depression of which we have geo- 
logical evidence has been exceedingly gradual, very limited in 
extent, and always balanced by adjacent opposite movements. Such 



270 THE WORLD OF LIFE 

movements appear to be slow creeping undulations passing over 
continental plateaus and their immediately adjacent submarine 
extensions. Sometimes the depressions seem to have taken the 
form of basins; but we cannot conceive of any elevation of conti- 
nental dimensions, or depression of oceanic character as to depth 
and area, without the complementary movement to complete the un- 
dulation. A continental extension between South America and 
Australia would almost necessarily imply a subsidence of one or 
both of those countries over an equal area and to an equal depth; 
and, so far as I am aware, no geological evidence has been ad- 
duced of any such vast changes having occurred at so recent a 
period in either continent. I believe it can now be truly said that 
no stratigraphical geologist accepts the theory of frequent inter- 
changes of continental and oceanic areas, which are so hastily 
claimed by palaeontologists and biologists to be necessary in order 
to overcome each apparent difficulty in the distribution of living 
or extinct organisms, and this notwithstanding the number of such 
difficulties which later discoveries have shown to be non-existent. 



CHAPTER XIII 

SOME EXTENSIONS OF DARWIn's THEORY 

During the fifty years that have elapsed since the Darwinian 
theory was first adequately, though not exhaustively, set fortli, 
it has been subject to more than the usual amount of ob- 
jection and misapprehension both by ignorant and learned 
critics, by old-fashioned field-naturalists, and by the newer 
schools of physiological specialists. Most of these objections 
have been shown to be fallacious by some of the most eminent 
students of evolution both here and on the Continent; but 
a few still remain as stumbling-blocks to many earnest readers, 
and, as they are continually adduced as being serious difii- 
culties to the acceptance of natural selection as a sufficient ex- 
planation of the origin of species, I propose to give a short 
statement of what seem to me the three objections that most 
require an answer at the present time. They are the follow- 
ing:— 

1. How can the beginnings of new organs be explained ? 

2. How can the exact co-ordination of variations, needed 
to produce any beneficial result, be effected with sufficient 
rapidity and certainty ? 

3. How is it that excessive developments of bulk, weapons, 
ornaments, or colours, far beyond any utilitarian requirements, 
have been so frequently produced ? 

These three objections are of increasing degrees of impor- 
tance. The first is, in my opinion, wholly speculative and 
of no value, inasmuch as it applies to wliat happened in the 
earlier stages of evolution, of which we have a mininium 
of knowledge. The second is of somrwliat more importance: 
for, though in the great majority of cases of adaptation the 
ordinarv well-known facts of variation and survival would 

271 



272 THE WORLD OF LIFE 

amply suffice, yet there are conceivable cases in wbich they 
might be insufficient, and these cases are now explained by 
a very interesting combination of the effects of acquired 
modifications of the individual with the selection of congenital 
variations. The third is, I think, somewhat more important, 
as indicating a real deficiency in the theory, as originally 
stated, but which is now well supplied by an extension of 
that theory from the body itself to the reproductive germs 
from which its parts are developed. I will, therefore, en- 
deavour to explain in as simple a manner as possible how 
these three objections have been overcome. 

(1) The Beginnings of Organs 

The objection that the first slight beginnings of new organs 
would be useless, and that they could not be preserved and 
increased by natural selection, was one of the most frequent 
in the early stages of the discussion of the theory, and was 
answered by Darwin himself in the later editions of his book. 
But the objection still continues to be made, and owing to 
the great mass of controversial literature continually issued 
from the press many of the objectors do not see the replies 
made to them ; there is therefore still room for a somewhat 
more general answer, wdiich will apply not only to certain 
individual cases, but to all. The most general and therefore 
the best answ^er I have yet seen given is that of Professor 
E. B. Poulton in his recently published Essays on Evolution. 
He says: 

" Organs are rarely formed anew in an animal, but they are 
formed by the modification of pre-existing organs ; so that, instead 
of having one beginning for each organ, we have to push the be- 
ginning further and further back, and find that a single origin ac- 
counts for several successive organs, or at any rate several functions, 
instead of one." 

He then goes on to show that the four limbs of vertebrates 
have been again and again modified, for running, for climbing 



to? 



EXTEXSIOXS OF DARWINISM 273 

for burrowing, for swimming, or for flying, and that their 
first appearance goes back to PalaBozoic times in the paired 
fins of early fishes, while their actual or'ujiii must have been 
much further back, in creatures whose skeleton was not suffi- 
ciently solidified to be preserved. 

There is, however, a more general explanation even than 
this, and one that applies to what has always been hehl to 
be the most difiicult of all — that of the origin of the organs 
of sense. 

The various sensations by which w^e come into relation with 
the external world — sight, hearing, smell, taste, and touch 
■ — are really all specialisations of the last and most general, 
that of material contact. We hear by means of a certain 
range of air-waves acting on a specially constructed vibrating 
organ ; we smell by the contact of excessively minute particles, 
or actual molecules, given off by certain substances ; we taste 
by the action of soluble matter in food on the papilke of the 
tongue; and we see by the impact of ether-vibrations on the 
retina; and as other ether-vibrations produce sensations of 
cold or warmth, or, when in excess, acute pain, in every part 
of the body, the modern view, that matter and ether are funda- 
mentally connected if not identical, seems not unreasonable. 

Xow, as all our organs of sense, however complex, are built 
up from the protoplasm which constitutes the material of all 
living organisms, and as all animals, however simple, exhibit 
reactions which seem to imply that they have the rudiments 
of most, if not all of our senses, we may conclude that just 
in proportion as they have advanced in complexity of organi- 
sation, so have special parts of their bodies become adapted 
to receive, and their nervous system to respond to, tlio varinn? 
contacts with the outer world which produce what wo terra 
sensations. There is therefore, probably, no point in the 
whole enormous length of the cliain of being, fnnn ourselves 
back to the simple one-celled Amoeba, iu which the rudiments 
of our five senses did not exist, although no separnto organs 
may be detected. Just as its whole body sen'os alternately 



274 THE WORLD OF LIFE 

as outside or inside, as skin or as stomach, as limbs or as 
lips, so may every part of it receive a slightly different sensa- 
tion from a touch outside or a touch inside, from an air- 
vibration or from an ether-vibration, from those emanations 
which effect us as noxious odours or disgusting tastes. But 
if this view is a sound one, as I think it will be admitted 
that it is, how absurd is it to ask, " How did the eye or the 
ear begin ? " They began in the potentiality of that marvel- 
lous substance, protoplasm, and they were rendered possible 
when that substance was endowed with the mysterious or- 
ganising power we term life. First the cell was produced; 
and, from the continued subdivision of the cell at each sub- 
division taking a slightly different form and function, numer- 
ous one-celled animals were formed; and a little later the 
union of many cells of diverse forms and functions led to the 
endless multicellular creatures, constituting the entire world of 
life. 

Thus every substance and every organ came into existence 
when required by the organism imder the law of perpetual 
variation and survival of the fittest, only limited by the 
potentialities of living protoplasm. And if the higher sense- 
organs were so produced, how much easier was the production 
of such superficial appendages as horns and tusks, scales and 
feathers, as they were required. Horns, for instance, are 
either dermal or osseous outgrowths or a combination of both. 
In the very earliest known vertebrates, the fishes of the 
Silurian formation, we find the skin more or less covered with 
tubercles, or plates, or spines. Here we have the rudiments 
of all those dermal or osseous outgrowths which continue in 
endless modifications through the countless ages that have 
elapsed down to our own times. They appear and disappear, 
as they are useful or useless, on various parts of the body, 
as that body changes in form and in structure, and modifi- 
cations of its external covering are needed. Hence the in- 
finite variety in nature — a variety which, were it not so 
familiar, would be beyond the wildest flights of imagination 



EXTENSIONS OF DARWINISM 275 

to suggest as possible developments from an apparently simple 
protoplasmic cell. The idea, therefore, that there were, or 
could be, at any successive periods, anything of the nature of 
the abrupt beginning of completely new organs which had 
nothing analogous in preceding generations is quite unsup- 
ported by what is known of the progressive development of 
all structures through slight modification of those which pre- 
ceded them. The objection as to the heglmiings of new organs 
is a purely imaginary one, wdiich entirely falls to pieces in 
view of the wdiole known process of development from the 
simplest cell (though in reality no cell is simple) to ever 
higher and more complex aggregations of cells, till we come 
to Mammalia and to man. 

(2) The Co-ordination of Variations 

The next difficulty, one which Herbert Spencer laid much 
stress on, is, that every variation, to be of any use to a species, 
requires a number of concurrent variations, often in dilTerent 
parts of the body, and these, it is said, cannot be left to 
chance. Herbert Spencer discussed this poi';t at great length 
in his Factors of Organic Evolution ; and, as one of the illus- 
trative cases, he takes the giraffe, w^hose enormously long neck 
and fore-legs, he thinks, would have required so many con- 
current variations that we cannot suppose them to have oc- 
curred through ordinary variation. He therefore argues that 
the inherited effects of use and disuse are the onlv causes 
which could have brought it about; and Darwin himself ap- 
pears to have thought that such inheritance did actually occur. 

The points which Spencer mainly dwells upon are as fol- 
lows : The increased length and massiveness of the neck 
would require increased size and strength of the chest with 
its bones and muscles to bear the additional weight, and also 
great additions to the strength of the fore-legs to carry such 
a burthen. Again, as the hind-legs have remained short, the 
whole body is at a different angle from what it was before 
the change from the ordinary antelope-type, and this would 



276 THE WORLD OE LIFE 

require a different shape in the articulating joints of the hips 
and some change in the muscles; and this would be the more 
important as the hind- and fore-legs now have unequal angular 
motions when galloping, involving changed co-ordination in 
all the connected parts, any failure in which would diminish 
speed and thus be fatal to the varying individuals. Even 
the blood-vessels and nerves of these various parts would re- 
quire modifioations exactly adapted to the change in the other 
parts ; and he urges that any individuals in Avhich all these 
necessary variations did not take place simultaneously, would 
be at a disadvantage and would not survive. To do his argu- 
ment justice, I will quote one of his most forcible paragraphs. 

" The immense change in the ratio of fore-quarters to hind- 
quarters would make requisite a corresponding change of ratio in 
the appliances carr3dng on the nutrition of the two. The entire 
vascular system, arterial and venous, would have to undergo succes- 
sive unbuildings and rebuildings to make its channels everywhere 
adequate to the local requirements, since any want of adjustment 
in the blood-supply to this or that set of muscles would entail in- 
capacity, failure of speed, and loss of life. Moreover, the nerves 
supplying the various sets of muscles would have to be appropriately 
changed, as well as the central nervous tracts from which they 
issued. Can we suppose that all these appropriate changes, too, 
would be, step by step, simultaneously made by fortunate spon- 
taneous variations occurring along with all the other fortunate 
spontaneous variations? Considering how immense must be the 
number of these required changes, added to the changes above 
enumerated, the chances against any adequate readjustments for- 
tuitously arising must be infinity to one." 

Xow, this seems very forcible, and has, no doubt, con- 
vinced many readers. Yet the argument is entirely fallacious, 
because it is founded on the tacit assumption that the number 
of the varying individuals is very small, and that the amount 
of coincident variation is also both small and rare. It is 
further founded on the assumption that the time allowed for 
the production of any sufficient change to be of use is also 



EXTEIsTSIONS OF DARWINISM 277 

small. But I have shown in the early chapters of this book 
(and much more fully in my Darwinism) that all these as- 
sumptions are the very reverse of the known facts. The 
numbers of varying individuals in any dominant species (and 
it is only these which become modified into new species) is 
to be counted by millions ; and as the whole number can, as 
regards any needed modification, be divided into two lialves 
— those which possess the special quality required above or 
below the average — it may be said thali nearly half the total 
number vary favourably, and about one-fourth of the whole 
number in a very large degree. Again, it has been shown 
that the number of coincident variations are very great, since 
they are always present when only a dozen or twenty individ- 
uals are compared; bnt nature deals with thousands and mil- 
lions of individuals. Yet, again, we know that changes of the 
environment are always very slow as measured by years or 
generations, since not a single new species is known to have 
come into existence during the whole of the Pleistocene period ; 
and as fresh variations occur in every generation, almost any 
character, with all its co-ordinated structures, would be con- 
siderably modified in a hundred or a thousand generations, and 
■we have no absolute knowledge that any great change would 
be required in less time than this.^ 

lA very familiar fact will, I think, show that a large amount of co- 
ordinated variability in different directions does actually occur. First-rate 
bowlers and wicket-keepers, as well as first-rate batters, are not common in 
proportion to the whole population of cricket-players. Each one of these 
requires a special set of co-ordinated faculties — good eyesight, accurate 
\ perception of distance and of time, with extremely rapid and accurate re- 
sponse of all the muscles concerned in the operations each has to perform. 
If all the special variations required to produce such individuals were sot 
forth by a good physiologist in the detailed and forcible manner of the 
passage quoted from Spencer about the giraffe, it would seem impossible 
that good cricketers should ever arise from the average family types. Yat 
they certainly do so arise. And just as cricketers are chosen, not by ex- 
ternal characters, but by the results of actual work, so nature selects, not by 
special characters or faculties, but by that combination of characters which 
gives the greatest chance of survival in the complex, fluctuating environment 
in which each creatures lives. The species thus lK»comes adapted, first to 



278 THE WORLD OF LIFE 

Objectors always forget that a dominant species has become 
so because it is sufficiently adapted to its whole environment, 
not only at any one time or to any average of conditions, 
but to the most extreme adverse conditions Avhicli have oc- 
curred during the thousands or millions of years of its exist- 
ence as a species. This implies that, for all ordinary con- 
ditions and all such adverse changes as occur but once in a 
century of a millennium, the species has a surplus of adapt- 
ability which allows it to keep up its immense population in 
the midst of countless competitors and enemies. Examples 
of such thoroughly well-adapted species were the American 
bison and passenger pigeon, whose populations a century ago 
were to be counted by millions and thousands of inillions, 
which they w^ere fully able to maintain against all enemies 
and competitors then in existence. But civilised man has so 
modified and devastated the whole organic environment in a 
single century as to bring about an extermination which the 
slow changes of nature would almost certainly not have ef- 
fected in a thousand or even a million of centuries. This 
happened because the changes were different in kind, as well 
as in rapidity, 'from any of nature's changes during the whole 
period of the development of existing species. 

But although I feel confident that the known amount of 
variation would amply suffice for the adaptation of any domi- 
nant species to a nomially changing environment, I admit that 
there are conceivable cases in which changes may have been 
so great and so comparatively rapid as to endanger the exist- 
ence even of some of those species which had attained to a 
dominant position; such, for instance, as the opening of a land 
passage for very powerful new Carnivora into another con- 
resist one danger, then another; first to one aspect of the ever-changing 
environment, then to another; till during successive generations it becomes 
so perfectly adapted to a long series of more or less injurious conditions, 
that, under all ordinary conditions, it possesses a surplus of adaptation. 
And as this complete adaptation is as often exhibited in colour and marking 
as in structure, it is proved that the transmission of the effects of use and 
disuse are not essential to the most complex adaptations. 



EXTEXSIO.\S OF DAKWJMSM l>70 

tinent or extensive area (as appears to have occurred with 
Africa in Tertiary times), in ^vllicll case it is quite possible 
that such an animal as the American bison mii^ht have been 
first reduced in numbers, and, for want of any suflicieutly 
rapid development of new means of protection, be ultimately 
destroyed. 

But a few years ago an idea occurred independently to three 
biologists, of a self-acting jorinciple in nature which would be 
of such assistance to any species in danger of extermination 
as, in some cases at all events, would enable it to become 
adapted to the new conditions. It would, in fact, increase the 
powers of natural selection, as above explainc(l, to a degree 
which might sometimes make all the difference between life 
and death to a certain number of species. It depends upon 
the w^ell-known fact that the use of any limb or organ strength- 
ens or increases the growth of that part or organ. On this 
fact depends all training for athletics or games; and it is 
alleged by some trainers that any one, however weak naturally, 
can have his strength very greatly increased by systematic 
but carefully graded exercise. If, therefore, the survival of 
any animal in presence of a new enemy or unaccustomed 
danger depends upon increased powers of running, or jumping, 
or tree-climbing, or swimming, then, during the process of 
eliminating those individuals who were the worst in these re- 
spects, all the remainder would have to exercise their powers 
to the utmost, and would, in the act of doing so, increase 
their power of escaping the danger. Thus a con-idrrable 
number would become capable of surviving, year after year, to 
a normal old age, and during this whole period would, year 
by year, have fresh descendants, and of these only the very 
best, the most gifted naturally, would survive. The in- 
creased adaptation during the life of the individual would not 
be transmitted, but the quality of being inijirovablc during life 
would be transmitted, and thus additional tim*^ and a consider- 
ablv increased ]K>])ulation would give more uuUcrials for 
natural selection to act upon. With this help the species 



280 THE WOKLD OF LIFE 

might become so rapidly improved that the danger from the 
new environment would be overcome, and a new type might 
be produced which would continue to be a dominant one un- 
der the new conditions.^ 

N^ow, while it must be admitted, that under certain con- 
ditions, and with certain classes of adaptations, the normal 
effects of natural selection would be facilitated by the aid of 
individual adaptation through use of organs, yet its effect is 
greatly limited by the fact that it will not apply to several 
classes of adaptations which are quite unaffected by use or 
exercise. Such are the colours of innumerable species, which 
are in the highest degree adaptive, either as protecting them 
from enemies, as a warning of hidden danger (stings, etc.), 
as recognition-marks for young or for wanderers, or by mimi- 
cry of protected groups. Here the tise is simply being seen 
or not seen, neither of which can affect the colour of the 
object. Again, nothing is more vitally important to many 
animals than the form, size, and structure of the teeth, which 

1 As many readers are ignorant of the extreme adaptability of many parts 
of the body, not only during an individual life, but in a much shorter period, 
I will here give an illustrative fact. A friend of mine was the resident 
physician of a large county lunatic asylum. During his rounds one morning, 
attended by one of his assistants and a warder, he stopped to converse with 
a male patient who was only insane on one point and whose conversation 
was very interesting. Suddenly the man sprang up and struck a violent 
blow at the doctor's neck with a large sharpened nail, and almost com- 
pletely severed the carotid artery. The warder seized the man, the assistant 
gave the alarm, while my friend sat down and pressed his finger on the 
proper spot to stop the violent flow of blood, which would otherwise have 
quickly produced coma and death. Other doctors soon applied proper pres- 
sure, and a competent surgeon was sent for, who, however, did not arrive 
for more than an hour. The artery was then tied up and the patient got 
to bed. He told me of this himself about two years afterwards, and, on 
my inquiry how the functions of the great artery had been renewed, he 
assured me that nothing but its permanent stoppage was possible, that 
numerous small anastomosing branches enlarged under the pressure and 
after a few months carried the whole current of blood that had before been 
carried by the great artery, without any pain, and that at the time of speak- 
ing he was quite as well as before the accident. Such a fact as this really 
answers almost the whole of Herbert Spencer's argument which I have 
quoted at p. 270. 



EXTEXSIONS OF DARWl.XLSM i'8l 

are wonderfully varied throughout the whole of th(^ VLricbrate 
sub-kingdom. Yet the more or less use of the teeth cannot 
be shown to have any tendency to change their fnnii or 
structure in the special ways in which they have been again 
and again changed, though it might possibly have induced 
growth and increased size. Yet again, the scales or plates of 
reptiles, the feathers of birds, and the hairy covering of mam- 
mal?, have never been shown to have their special textures, 
shape?, or density modified by the mere act of use. One 
common error is that cold produces length and density of 
hair, heat the reverse ; but the purely tropical monkey-tribe 
are, as a rule, quite as well clothed with dense fur as most 
of the temperate or arctic mammals, while no birds are more 
luxuriantly feather-clad than those of the tropics. XeitlnT 
is it certain that increased gazing improves the eyes, or loud 
noises the ears, or increased eating the stomach ; so that we 
must conclude that this aid to the powers of natural selection 
is very partial in its action, and that it has no claim to the 
important position sometimes given it. 

(3) Germinal Seleclion, an Important Eximfiion of the 

Theory of Natural Selection 

Although I was at first inclined to accept Darwin's view of 
the influence of female choice in determining the development 
of ornamental colour or appendages in the males, yet, when 
he had a(hhiced his wonderful array of facts bearing upon 
the question in the Descent of Man, the evidence for any such 
effective choice appeared so very scanty, and the ellects im- 
puted to it so amazingly improbable, that T felt certain that 
some other cause was at work. Tn my Tropical Nature 
(1878) and in my Darwinism (1889) I treated the subject 
at considerable length, adducing many facts to prove that, even 
in birds, the colours and ornamental })lunies of the males were 
not in themselves attractive, but served merely as signs of 
sexual maturity and vigour. Tn the case of insects, especially 
in butterflies, where the phenomena of colour, and to some 



282 THE WOKLD OE LIEE 

extent of ornament, are strikingly similar to those of birds, 
the conception of a deliberate aesthetic choice, by the females, 
of the details of colour marking, and shape of wings, seemed 
almost unthinkable, and was supported by even less evidence 
than in the case of birds. 

After long consideration of the question in all its bearings, 
and taking account of the various suggestions that had been 
made by competent observers, I arrived at certain conclu- 
sions which I stated as follows : 

" The various causes of colour in the animal world are, molecular 
and chemical change of the substance of their integuments, or the 
action upon it of heat, light, or moisture. Colour is also produced 
by the interference of light in superposed transparent lamellae or by 
excessively fine surface striae. These elementary conditions for the 
production of colour are found everywhere in the surface-structures 
of animals, so that its presence must be looked upon as normal, its 
absence exceptional. 

" Colours are fixed or modified in animals by natural selection 
for various purposes : obscure or imitative colours for concealment ; 
gaudy colours as a warning; and special markings either for easy 
recognition by strayed individuals or by young, or to divert attack 
from a vital part, as in the large brilliantly marked wings of some 
butterflies and moths. 

" Colours are produced or intensified by processes of develop- 
ment, either where the integument or its appendages undergo great 
extension or change of form, or where there is a surplus of vital 
energy, as in male animals generally, more especially at the breed- 
ing season." ^ 

ISTow the idea here suggested, of all these strange and beau- 
tiful developments of plumage, of ornaments, or of colour 
being primarily due to surplus vitality and growth-power in 
dominant species, and especially in the males, seems a fairly 
adequate solution of the problem. For the individuals which 
possessed it in the highest degree would survive longest, would 

1 Natural Selection and Tropical Nature (new ed., 1895), pp. 391-392. 
For full details see Darwinism, chap. x. (1901). 



EXTENSIONS OF DARWINISM 283 

have most offspring who were equally or even more hijrhly 
gifted; and thus there would arise a continually increasing 
vitality whicli would be partly expended in the further develop- 
ment of those ornaments and plumes which are its result and 
outward manifestation. The varvine^ conditions of existence 
would determine the particular part of tlie body at which such 
accessory ornaments miglit arise, usually^ no doubt, directed 
by utility to the species. Thus the glorious train of the pea- 
cock might have begim in mere density of plumage covering 
a vital part and one specially subject to attack by birrls or 
beasts of prey, and, once started, these plumes would continue 
to increase in number and size, as being an outlet for vital 
energy, till at last they became so enormously lengthened as 
to become dangerous by their weight being a check to speed 
in running or agility in taking flight. This is already the 
case with the peacock, which has some difficulty in rising from 
the ground and flies very heavily. Its enemies in India are 
tigers and all the larger members of the cat-tribe, and when 
any of these approach its feeding-grounds it takes alarm and 
at once flies up to the low^er branches of large trees. In the 
ArgTis-pheasant it is the secondary wing-featliers that are ex- 
ceedingly long and broad, so as to be almost as much a liin- 
drance to strong or rapid flight as is the train of the pea- 
cock; and in both birds these ornamental plumes have evi- 
dently reached the utmost dimensions compatible with the 
safety of the species. 

There can also be little doubt that in manv of the birds- 
of-paradise and of the humming-birds, in the enormous crest 
of the umbrella-bird, in the huge beaks of the hornbiils and 
the toucans, in the lenc^thv neck and lec:s of the flaminc:os and 
the herons, these various oraamental or usefid appen(iag(\>< liave 
reached or even overpassed the maximum of utility. In an- 
other class of animals we have the same phenomenon. The 
expansion of the wings in butlerflies and motlis reaches a 
maximum in several distinct families — the Papilionidre, the 
Morphidffi, the Bond\vces, au'l the Xoctuje, in all <>f whirli it 



2S4 THE WORLD OF LIFE 

is sometimes from nine to ten inches. Here, again, we seem 
to find a tendency to development in size, which has gone on 
from age to age, till limits have been reached to exceed which 
threatens the existence of the species. 

The progressive development of many groups of animals 
affords curious illustrations of this continuous increase in bulk, 
or in the size of particular organs, till they have actually over- 
passed the line of permanent safety, and under the first ad- 
verse conditions have led to extinction. Both reptiles and 
mammals originated in creatures of small size which gradually 
increased in bulk, in certain types, till they suddenly became 
exterminated. In the former class the increase was ap- 
parently rapid, till the hugest land-animals that ever lived 
appeared upon the earth — the Dinosauria of the Jurassic and 
Cretaceous periods, already described. Many of them also de- 
veloped strange horns and teeth; and these, too, when they 
reached their maximum, also suddenly disappeared. Flying 
reptiles — the Pterodactyles — also began as small animals 
and continually increased, till those of the period of our Chalk 
attained the greatest dimensions ever reached by a flying crea- 
ture, and then the whole group became extinct at a time when 
a higher type, the birds, w^ere rapidly developing. 

With mammals the case is even more striking, all the ear- 
liest forms of the Secondary age being quite small; while in 
the Tertiary period they began to increase in size and to de- 
velop into a great variety of types of structure ; till, in an 
age just previous to our own, such exceedingly diverse groups 
as the marsupials, the sloths, the elephants, the camels, and 
the deer, all reached their maximum of size and variety of 
strange forms, the most developed of which then became ex- 
tinct. Others of a lower and more generalised type, but 
equally bulky, had successively disappeared at the termina- 
tion of each subdivision of the Tertiary age. It is here that 
we can trace the specialisation and increase in size of the 
horse-tribe and of the deer; tlie latter passing from a horn- 
less state to one of simple horns, gradually increasing in size 




Fig. 94. — MacJurrodus neogwus ( Sabre-Toothed Ti<,n'r). 
From the Pleistocene of Buenos Ayres. One-eighth nat. size. (Nicholson's 

Palaeontology.) 




Fig. 95. — Skeleton of liiuiit Deer {Ccrrus <ii;i(iiilruft) . (li.M. (Juide.) 

From a peat-bog in Ireland. One-thirtieth nat. size. 

The antlers were often 9 feet across from tip to tip, sometimes 11 feet. 



EXTENSIONS OF DARWINISM 285 

and complexity of branching, till they culminated in tlic great 
Irish elk, which was the contemporary of the mammoth and 
man in our own country. 

Dr. A. S. Woodward, keeper of Geology in the British 
Museum, discussed this curious phcnumenou in his presi- 
dential address to the Geological Section of the British Asso- 
ciation in 1909 ; and a few extracts will show how widespread 
are these facts, and the great interest they have excited. 
After sketching out the whole course of animal development, 
and showing how universal is the law (much empliasised by 
Darwin), that the higher form of one group never developed 
from similar forms of a preceding lower type, but that both 
arose from an early, more generalised type, he says: 

*' To have proved, for example, that flying reptiles did not pass 
into birds or bats, that hoofed Dinosaurs did not change into 
hoofed mammals, and that Ichthyosaurs did not become porpoises, 
and to have shown that all these later animals were mere mimics 
of their ^predecessors, originating independently from a higher yet 
generalised stock, is a remarkable achievement." 

Then comes a reference to the subject we are now discuss- 
ing: 

" Still more significant, howeve-r, is the discovery, that towards 
the end of their career through geological time, totally difTerent 
races of animals repeatedly exhibit certain peculiar features which 
can only be described as infallible marks of old age. The growth 
to a very large size is one of these marks, as we observe in the 
giant Pterodactyls of the Cretaceous i^eriod, the colossal Dinosaurs 
of the Upper Jurassic and Cretaceous, and the large mammals of 
the Pleistocene and the present day. It is not, of course, all the 
members of a race that increase in size; some remain small until 
the end, and they generally survive long after the others are ex- 
tinct. 

"Another frequent mark of old age In races was first discussed 
and clearly pointed out by Professor C. E. Beechor of Yale. It is 
the tendency of all animals with skeletons to produce a superfluity 
of dead matter, which accumulates in the form of spines or bosses 



28G THE WOKLD OF LIFE 

as soon as the race they represent has reached its prime and begins 
to be on the down grade. Among famiUar instances may be men- 
tioned the curiously spiny Graptolites at the end of the Silurian, the 
horned Pariasaurians at the beginning of the Trias, the armour- 
plated and horned Dinosaurs at the end of the Cretaceous, and the 
cattle or deer of modern Tertiary times. . . . The growth of 
these excrescences, both in relative size and complication, was con- 
tinual and persistent until the climax was reached and the extreme 
forms died out. ... 

" It appears, indeed, that when some part of an animal (whether 
an excrescence or a normal structure) began to grow relatively 
large in successive generations during geological time, it often ac- 
quired some mysterious impetus by which it continued to increase 
long after it had reached the serviceable limit. The unwieldy 
antlers of the extinct Sedgwick's deer and Irish deer (Fig. 95), 
for example, must have been impediments rather than useful 
weapons. Tlie excessive enlargement of the upper canine teeth in 
the sabre-toothed tigers (Machaerodus and its allies) must also 
eventually have hindered rather than aided the capture and eating 
of prey.'' ^ 

Dr. Woodward further remarks: 

" The curious gradual elongation of the face in the Oligocene 
and Miocene Mastodons can only be regarded as another illustra- 
tion of the same phenomenon. In successive generations of these 
animals the limbs seem to have grown continually longer, while the 
neck remained short, so that the head necessarily became more and 
more elongated to crop the vegetation on the ground. A limit of 
mechanical efficiency was eventually reached, and then there sur- 
vived only those members of the group in which the attenuated 
mandibles became shortened, leaving the modified face to act as a 

1 The species Maclicerodus neogceus, the skull of which is shewn in Fig. 94, 
appears lo have had the largest canines of any species of the genus; and we 
are told by Messrs. Xicholson and Lydekker (Manual of Palaeontology^ ii. p. 
1449) that the upper carnassial tooth (the fourth premolar) "has four 
distinct lobes, and is thus the most complex example of this type of tooth 
known." The canines were about 9 inches long (more than half the length 
of the whole skull), and very massive in proportion. It became extinct in 
South America in the Pleistocene period, about the same time as the last of 
the European species. 



exte^sio:n's of darwixism 



28' 



proboscis. Tlie elephants thus arose as a kind of aftertlioiiglit 
from a group of quadrupeds that were rapidly approaching tlicir 
doom." (See figures in last chapter, p. :^-")7.) 

This last is a specially interesting case, because it is the 
only^ one in which, without change of general environnifnt, 
or apparently of habits, a highly developed animal has re- 
traced its latest steps, and then advanced in a new line of de- 
velopment, leading to the wonderful trunk and the cnurmous 
tusks of the modern elephant, as explained in Chapter XIT. 
That these have now attained the maximum of useful growth 
is indicated bv the fact that amoni>: the extinct fonus are those 
in which they are developed to an unwieldy size, as in Elephas 
ganesa of Xorth-West India, whose slightly curved tusks, some- 
times nearly 10 feet long, must have put an enormous strain 
upon the neck, and the mammoth, whose greatly curved tusks 
were almost equally heavy. 

Excessive Development of Lower Animals before Extinction 

My friend Professor Judd has called my attention to the 
fact that many of the lower forms of life exhibited similar 
phenomena. The Trilobites (primitive crustaceans) which 
were extremely abundant in the Pala?ozoic rocks, in their last 





Fig. 96. — Conocoryphc sultzcri. 
Upper Cambrian. 



Fio. 97. — Paradonides bohcmicus. 
Upper Cambrian. 



288 



THE WORLD OF LIFE 



stages " developed strange knobs and spikes on their shells, so 
that thej seemed to be trying experiments in excessive vari- 
ation.'^ 

Figs. 96, 97^ show typical forms of Trilobites (so called 
from their three-lobed bodies) ; while at a later period, when 
the whole group was approaching extinction, it produced 
spined forms like that shown in Fig. 98. 

Excentric forms of Ammonites 

At a later period the wonderfully rich and varied Am- 
monites show still more curious changes. Beginning in the 

Devonian formation thev increased 
in varietv of form and structure 
all through the succeeding forma- 
tions, till they finally died out in 
the Cretaceous. The two species 
here figured from the Trias (Figs. 
99, 100) may be taken as typical; 
but the variations in surface pat- 
tern are almost infinite. Visitors 
to Weymouth or Lyme Regis maj" 
find such in abundance under Lias 
cliffs, or in the former place 
along the shores of the backwater. 
As time went on Ammonites in- 
FiG. ^^ — Acidaspis dufrenoyi. creased in maximum size, till in 

Silurian (Bohemia). 

the Chalk formation specimens 2 
or 3 feet diameter are not uncommon. One of the largest 
English specimens in the British Museiim (Xatural History) 
was found at Rottingdean, near Brighton, and is 3 feet 8 inches 
across; but the largest known is an allied species from the 
Upper Chalk of Westphalia, and has the enormous diameter 
of 6 feet 8 inches. 

It is an interesting fact that the very earliest Ammonites 
were straight, and gradually became closely coiled. This 
form was maintained almost constant throu2:hout the vast 




EXTENSIONS OF DARWINISM 



289 



periods of the Mesozoic age, till towards llie end, when the 
whole race was about to die out, they seemed to try to go 
back to their original form, which some almost reached (Fi^. 





Fig. 99. — Ceratites nodosus. 
Trias. 



Fig. 100. — Trachyceras aon. 
Trias. 



105), while others, as Professor Judd remarks (in a letter), 
" before finally disappearing, twisted and untwisted them- 
selves, and as it were wriggled themselves into extraordinary 





Fig. 101. — Crioceras emerici. 
Cretaceous. 



Fig. 102. — Ileteroceras cmcrici. 
Cretaceous. 



shapes, in the last throes of dissolution.'- These strange forms 
(Figs. 90-106) are reproduced from Nicholson's PaUeontol- 
ogy, and there are many others. 



290 



THE WOKLD OF LIFE 




Fig. 103. — Macroscapliites ivanii. 
Cretaceous. ' 




Fig. 104. — Hamites rotundus. 

Cretaceous. 




Fig. 105. — Ptychoceras emericianum. 

Cretaceous. 





Fig. lOG. — Ancyloceras Matheronianum. 

Gault. 
Late Ammonites. (From Nicholson's Palaeontology.) 

Special Features in the Development of Vertehrates 

Another remarkable fact dwelt upon in Dr. Woodward's 
address is the remarkably small brains of those early types 
of vertebrates which were not destined to survive. The most 



EXTE:^rSIOXS of DARWIXISM 291 

striking cases are those of the Mesozoic reptiles and the early 
Tertiary ungulate mammals, which both increased to such an 
enormous bulk, yet retained throughout an almost ludicrously 
small brain, as described in the last chapter. The same was 
the case to a somewhat less extent with the carnivorous mam- 
mals, the Creodonta and Sparassodonta of the early Tertiaries 
both of the eastern and western hemispheres. These were 
sometimes as large as lions or bears, and had equally well de- 
veloped canine teeth, but very small brains; and they all died 
out in Eocene or early Miocene times, giving way to small an- 
cestral forms of our modern carnivores, which then increased 
in size and developed larger brains, culminating in the highly 
intelligent fox and dog, cat and leopard, of our own day. 

Yet another singular feature of some of the more highly 
developed vertebrates is the partial or total loss of teeth. This 
is well shown in the camels, which have only a pair uf in- 
cisors in the upper jaw; while the whole vast family of the 
deer, cattle, and sheep have a completely toothless pad in the 
front of the upper jaws. This is apparently better adapted 
for rapid browsing of grass and low herbage — whieli is stored 
up in the 23aunch for rumination when at rest; and the ab- 
sence of teeth as a defence is compensated by the possession 
of horns in a great variety of form and structure. 

Even more remarkable is the total loss of teeth bv modern 
birds, although the early types of birds possessed them. The 
bill, however, is often a very effective piercing or tearing 
weapon ; and their strongly grasping claws and hooked bill 
render the birds of prey almost as powerful and d instructive 
as the smaller members of the cat-tribe. This partial or total 
disappearance of the teeth has no doubt been helped on l)y the 
same principle which led to the persistent increase of useless 
appendages till checked by natural selection or till it led to 
the extinction of the entire race. 



292 THE WORLD OF LIFE 

Germinal Selection 

The numerous and varied phenomena which have been 
merely sketched in outline in the present chapter receive an 
approximate explanation by Professor Weismann's theory of 
germinal selection, which he first published in 1896. He 
appears to have been led to it by feeling the difficulty of ex- 
plaining many of these phenomena by the ^' natural selection " 
of Darwin; but to have laid more stress on those of Section 2 
of the present chapter than those of Section 3. He had in 
1892 published his elaborate volume on The Germ-Plasm a 
Theory of Heredity, to which this later theory is a logical 
sequel. 

During the last quarter of a century many striking discov- 
eries have been made in what may be termed the mechanism 
of growth and reproduction ; each successive advance in micro- 
scopic power and methods of observation have brought to light 
whole worlds of complex structure and purposive transfor- 
mations in w^hat was before looked upon as structureless cells 
or corpuscles. Some attempt will be made in a later chapter 
to discuss these primary life-phenomena; here it is only neces- 
sary to show briefly how Weismann's new theory helps us to 
understand the facts of life-development we have been dealing 
with. For this purpose I cannot do better than quote Pro- 
fessor Lloyd Morgan's very clear statement of the theory. 
He says : ^ 

" The additional factor which Dr. Weismann suggests is what 
he terms ^ germinal selection.' This, briefly stated, is as follows : — 
There is a competition for nutriment among those parts of the germ 
named determinants, from which the several organs or groups of 
organs are developed. In this competition the stronger deter- 
minants get the best of it, and are further developed at the expense 
of the weaker determinants, which are starved, and tend to dwin- 
dle and eventually disappear. The suggestion is interestingj but 
one well-nigh impossible to test by observation. If accepted as a 

1 Habit and Instinct, p. 310. 



EXTEJN^SIO^^S OF DAKWINISM 293 

factor, it would seiTe to account for the inordinate growth of cer- 
tain structures, such as the exuberance of some secondary sexual 
characters, and for the existence of determinate variations, that is 
to say, variations along special or particular lines of adaptation." 

It may be well to give here Weismann's own definition of 
what he means by " determinants," as quoted by Professor J. 
Arthur Thomson in his fine volume on Heredity (p. 435) : 

" ' I assume,' Weismann says, ^ that the germ-plasm consists of 
a large number of different parts, each of which stands in a definite 
relation to particular cells or kinds of cells in the organism to be 
developed — that is, tliey are * primary constituents' in the sense 
that their co-operation in the production of a particular part of the 
organism is indispensable, the part being determined both as to its 
existence and its nature by the predestined particles of the germ- 
plasm. I therefore call these Determinants, and the parts of the 
complete organism which they determine Determinates," ^ 

Professor Thomson continues thus: 

" But how many determinants are to be postulated in any given 
case? "Weismann supposes that every independently variable and 
independently heritable character is represented in the germ-plasm 
by a determinant. A lock of white hair among the dark may re- 
appear at the same place for several generations; it is difficult to 
interpret such facts of particular inheritance except on the theory 
that the germ -plasm is built up of a large number of different de- 
terminants. It may be pointed out that almost all biologists who 
have tried to form a conception of the ultimate structure of living 
matter have been led to the assumption — expressed in very varied 
phraseology — of ultimate protoplasmic units which have the power 
of growth and division. It is in no way peculiar to Weismann to 
imagine biophors and to credit them with the powers of growing 
and dividing.'' 

I quote these passages because Professor Thomson is thor- 
oughly acquainted, not only with all Weismann's work, having 
himself translated some of them, but also with that of other 

1 The Evolution Theory, 1004. vol. i. p. 355. 



294 THE WOELD OF LIFE 

European and American writers on this very difficult prob- 
lem; and he arrives at the conclusion, that Weismann's theory 
is the most carefully and logically worked out, and that some 
such conception is essential for a comprehension of the won- 
derfully complex phenomena of heredity. He also quite 
agrees with the conception that as these vital elements of the 
germ-plasm grow and multiply during the life of the organism, 
they must be nourished by fluids derived from it, and that 
there must be slight differences between them in size and 
vigour, and a struggle for existence in which the most vigorous 
survive. These more vigorous determinants will lead to more 
vigorous growth of the special part or organ they determine — 
hair, horns, ornaments, etc., — and wherever this increase is 
useful, or even not hurtful, to the species, it will go on in- 
creasing, generation after generation, by the survival of more 
and more vigorous determinants. 

There is therefore both an internal and an external strug- 
gle for existence affecting all the special parts — organs, or- 
naments, etc. — of ever}^ living thing. With regard to the 
more important sti-uctures, such as the limbs, the organs of 
vision and hearing, the teeth, stomach, heart, lungs, etc., on 
Avhich the very existence of the individual as well as of the 
species depends, survival of the fittest in due co-ordination 
with all other parts of the body will continually check any 
tendency to unbalanced development, and thus, generation by 
generation, suppress the tendency of the more vigorous de- 
terminants to increase the growth and vigour of its special 
determinates, by elimination of the individuals which exhibit 
such unbalanced gro^vth. But in the case of appendages, or- 
naments, or brilliant colours, which may begin as a mere out- 
let for superfluous vital energy in dominant races, and then 
be selected and utilised for purposes of recognition, warning, 
imitative concealment, or for combat among males, there w^ill 
not be the same danger to the ver)^ existence of the adult ani- 
mal. It will, however, often happen that the increase through 
germinal selection Avill continue beyond the point of absolute 



EXTENSlOiVS OF DxVK\VI.\i;SM 205 

utility to tlie individual; between which and the jooint of ef- 
fective hurtfulness there may be a considerable margin. In 
this way w^e have a quite intelligible exi)lanation of the enor- 
mous development of feathers or decorative pi Limes in so many 
birds, enormous horns in deer and antelopes, huge tusks in 
elephants, and huge canine teeth in other quadrupeds. Tliis 
view is supported by the suggestive fact, that many of these 
appendages are retained only for a short period, during the 
breeding season, when vigour is greatest and food most abun- 
dant, and when therefore they are least injurious. 

Again, when acting in an opposite direction, the theory 
serves to explain the rapid dwindling and final disappearance 
of some useless organs, which mere disuse is hardly sufficient 
to explain; such are the lost hind limbs of whales, llie rudi- 
mentary wings of the Apteryx, the toothless beak of birds, ete. 
In such cases, after natural selection had reduced the part to 
a rudimental condition, any regrowth would be injurious, and 
thus determinants of increased vigour would be suppressed 
by the non-survival of the adult, leaving the weaker deter- 
minants to be crowded out by the competition of those of ad- 
jacent parts, the increased development of which was ad- 
vantageous. 

By this very ingenious, but, though speculative, highly 
probable hypothesis, extending the s]:)hero of c<inipetition for 
nourishment and survival of the fittest from \\\o nTgani>=m as 
a whole to some of its elementarv vital units, Professor Weis- 
mann has, I think, overcome the one real diHieulty in the in- 
terpretation of the external forms of living things, in all their 
marvellous details, in tenns of normal .variation and survival 
of the fittest. We have here that '^ mysterious impetus " to 
increase beyond the useful limit which Dr. Woodward has rt^ 
ferred to in his address already quoted, and which is also 
a cause of the extinction of species to which Mr. Lydekker 
referred us, as quoted towards the end of the preceding chap- 
ter. 



296 THE WORLD OF LIFE 

Illustrative Cases of Extreme Development 

Two examples of this extreme development have not, I 
think, jet been noticed in this connection. The wonderful 
long and perfectly straight spirally twisted tusk of the strange 
Cetaceous mammal, the narw^hal, is formed by an extreme de- 
velopment, in the male only, of one of a pair of teeth in the 
upper jaw. All other teeth are rudimentary, as is the right 
tooth of the pair of which the left forms the tusk, often 7 
or 8 feet long, and formed of a very fine heavy ivory. The 
use of this is completely unknown, for though two males have 
been seen playing together, apparently, with their tusks, they 
do not fight, and their food, being small Crustacea and other 




Fig. 107. — Head of Babirusa {Bahirusa alfurus). 
The tusks of this animal continue growing during life. Those of the upper jaw are 
directed upward from the base so that they do not enter the mouth, but pierc- 
ing the skin of the face, resemble horns rather than teeth, and curve backwards 
and downwards. (Flower, Study of Mammals.) 

marine animals, can have no relation to this weapon. We 
may, however, suppose that the tusk was originally developed 
as a defence against some enemy, when the narwhal itself was 
smaller, and had a wider range beyond the Arctic seas which 
it now inhabits; and when the enemv had become extinct this 
strange weapon went on increasing through the law of germinal 
selection, and has thus become useless to the existing animaL 



EXTEiS^SIOXS OF DAEWIXISM 297 

The other case is that of the equally remarkable Babinisa 
of the islands of Celebes and Burn, in which the canines of 
the males are so developed as to be useless for fighting- (see 
Fig. 107). Here, too, there can be little doubt that the tusks 
were originally of the same type as in the wild boar, and were 
used for both attack and defence; but the ancestral form hav- 
ing been long isolated in a country where there were no ene- 
mies of importance, natural selection ceased to preser\'e thom 
in their original useful form, and the initial curvature became 
increased by germinal selection, while natural selection only 
checked such developments as would be injurious to the in- 
dividuals which exhibited them. 

A Wider Application of the Principle of Germ-Selection 

But it seems to me that the principle here suggested has a 
still higher importance, inasmuch as it has been the normal 
means of adding to and intensifying that endless varietv of 
form, that strange luxuriance of outgrowths, and that ex- 
quisite beauty of marking and brilliancy of colour, that ren- 
der the world of life an inexpressible delight to all who have 
been led to observe, to appreciate, or to study it. It is through 
the action of some such internal selecting agency that we owe 
much of what we must call the charming eccentricity of nature 
— of those exuberances of growth which cause the nature- 
lover to perpetually exclaim, " What can be the use of this ? '* 
In the birds-of-paradise we had long known of the tail- 
feathers, the breast-shields, the masses of plumage from under 
the wings, the crests, the neck-tippets, all in wonderful variety 
of shape and colour. Then, in the island of Batch iau 1 ob- 
tained a bird in which from the bend of the wing (correspond- 
ing to our wrist) there spring two slender and flexible white 
feathers on each side standine; out from the wine: durinc: ilii^ht, 
whence it has been termed the standard-winged bird-of-para- 
dise. Again, a few years ago, there was discovered in the 
mountains of German 'New Guinea another quite new type, in 
which, from the corner of each eye, a long plume arises more 



208 THE WORLD OF LIFE 

than twice the length of the bird's body, and having, on one 
side only of the midrib, a series of leaf-shaped thin horny 
plates of a beautiful light-blue colour on the upper surface, 
contrasting in a striking manner with the purple black, ochre 
yellow, and rusty red of the rest of the plumage. 

In the comparatively small number of birds-of -paradise 
now known, we have a series of strange ornamental plumes 
w^hich in their shape, their size, their colours, and their point 
of origin on the bird, exhibit more varietv than is found in 
any other family of birds, or perhaps in all other known birds ; 
and we can now better explain this by the assistance of Weis- 
mann's law in a highly dominant group inhabiting a region 
which is strikin^'lv deficient in animals wdiich are inimical to 
bird-life in a densely forest-clad country. 

To this same principle we must, I think, impute that su- 
perfluity of dazzling colour in many birds, but more especially 
in many insects, in which it so often seems to go far beyond 
usefulness for purposes of recognition, or as a warning, or a 
distracting dazzle to an attacking enemy. 

Even in the vegetable kingdom this same law may have 
acted in the production of enoiTQOus masses of flowers or of 
fruits, far beyond the needful purpose of perpetuating the 
species ; and probably also of those examples of excessive bril- 
liancy of colour, as in the intense blues of many gentians, the 
vivid scarlet of the Cardinal lobelia, or the glistening yellow 
of many of our buttercups. It is quite possible, therefore, 
that to this principle of ^' germinal selection " we owe some 
of the most exquisite refinements of beauty amid the endless 
variety of form and colour both of the animal and the veg- 
etable world. 

We may also owe to it the superabundant production of sap 
which enabled the early colonists of America to make almost 
imlimited quantities of sugar from the '^ sugar maple." 
Each tree will yield about four pounds of sugar yearly from 
about thirty gallons of sap ; and it is stated by Lindley that a 
tree wull yield this quantity for forty years without being at 



EXTENSIONS OF DARWINISM 299 

all injured; and large quantities of such sugar are still made 
for home consumption, the molasses produced from ii l)oing 
said to be superior in flavour to that from the sugar-cane. 
Here surely is a verv renuirkable case of an excessive sur- 
plus product which is of gTcat use to man, and, so far as 
we can see, to man only. The same phenomenon of a sur- 
plus product is presented by the Para rubber-trees (Sii)h«jnia, 
many species), from which, at the pro]ier season, larttc quan- 
tities of the precious sap can be withdrawn annually for very 
long periods, without injuring the trees, or producing a dimi- 
nution of the supply. There are also many other useful veg- 
etable products, among those referred to in our fifteenth chaj)- 
ter, to which the same remark will apply ; and it seems prrib- 
able that we owe the whole of these, and many others not yet 
discovered in the vast unexplored tropical forests, to this far- 
reaching principle of " germinal selection.'^ 

General Conclusions as to Life-Development 

Before quitting the subject of the course of development of 
the entire world of life as shown by the geological record, to 
which the present chapter is in a measure supplementary, it 
will be w^ell to say something as to its broader features from 
the point of view adopted in this work. This is, that beyond 
all the phenomena of nature and their immediate causes and 
laws there is Mind and Purpose; and that the ultimate pur- 
pose is (so far as we can discern) the development of mankind 
for an enduring spiritual existence. With this object in view- 
it would be important to supply all possible aids that a ma- 
terial world can give for the training and education of man's 
higlier intellectual, moral, and aesthetic nature. If this view 
is the true one, we may look upon our Universe, in all its parts 
and durinc; its whole existence, as slowlv ]>ut surelv marchiui:: 
onwards to a predestined end ; and this involves the further 
conception, that now that man /m.s^ boon dovolojiod, tliat lio is 
in full possession of this earth, and that upon his proper use 
of it his adequate preparation for the future life depends, then 



300 THE WORLD OF LIFE 

a great responsibility is placed upon him for the way in which 
he deals with this his great heritage from all the ages, not only 
as regards himself and his fellows of the present generation, 
but towards the unknown multitude of future generations that 
are to succeed him. 

x\ll of us who are led to believe that there must be a being 
or beings high and powerful enough to have been the real 
cause of the material cosmos with its products life and mind, 
can hardly escape from the old and much-derided view, that 
this world of ours is the best of all possible worlds calculated 
to bring about this result. And if the best for its special pur- 
pose, then the whole course of life-development was the best; 
then also every step in that development and every outcome 
of it which we find in the living things which are our con- 
temporaries are also the best — are here for a purpose in some 
way connected with us; and if in our blind ignorance or 
prejudice we destroy them before we have earnestly endeav- 
oured to learn the lesson thev are intended to teach us, w^e 
and our successors will be the losers — morally, intellectually, 
and perhaps even physically. 

Already in the progress of this work I have dwelt upon the 
marvellous variety of the useful or beautiful products of the 
vegetable and animal kingdoms far beyond their o^^TL uses, as 
indicating a development for the ser^uce of man. This variety 
and beauty, even the strangeness, the ugliness, and the unex- 
pectedness we find everywhere in nature, are, and therefore 
were intended to be, an important factor in our mental de- 
velopment ; for they excite in us admiration, wonder, and 
curiosity — the three emotions which stimulate first our at- 
tention, then our determination to learn the how and the why, 
which are the basis of observation and experiment and there- 
fore of all science and all philosophy. These considerations 
should lead us to look upon all the works of nature, animate or 
inanimate, as invested with a certain sanctity, to be used by 
us but not abused, and never to be recklessly destroyed or de- 
faced. To pollute a spring or a river, to exterminate a bird 



EXTENSIONS OF DARWINISM 301 

or beast, should be treated as moral offences and as social 
crimes; while all who profess religion or sincerely believe in 
the Deity — the designer and maker of this world and of every 
living thing — should, one would have thought, have placed 
this among the first of their forbidden sins, since to deface 
or destroy that which has been brought into existence for the 
use and enjoyment, the education and elevation of the human 
race, is a direct denial of the wisdom and goodness of the 
Creator, about which thej so loudly and persistently prate and 
preach. 

Yet during the past century, which has seen those great ad- 
vances in the Tcnowledge of Nature of which we are so proud, 
there has been no corresponding development of a love or rev- 
erence for her works ; so that never before has there been such 
widespread ravage of the earth's surface by destruction of 
native vegetation and with it of much animal life, and such 
wholesale defacement of the earth by mineral workings and 
by pouring into our streams and rivers the refuse of manufac- 
tories and of cities; and this has been done by all the greatest 
nations claiming the first place for civilisation and religion ! 
And what is Avorse, the greater part of this waste and devas- 
tation has been and is being carried on, not for any good or 
worthy purpose, but in the interest of personal greed and 
avarice; so that in every case, while wealth has increased in 
the hands of the few, millions are still living without the bare 
necessaries for a healthy or a decent life, thousands dying 
yearly of actual starvation, and other thousands being slowly 
or suddenly destroyed by hideous diseases or accidents, directly 
caused in this cruel race for wealth, and in ahuost everv case 
easily preventable. Yet they are not ])revented, solely be- 
cause to do so would somewhat diminish th(^ })rofits of the 
capitalists and legislators who are directly responsible for this 
almost world-wide defacement and destruction, and virtual 
massacre of the ignorant and defenceless workers. 

The nineteenth century saw the rise, the development, and 
the culmination of these crimes against God and man. Let 



302 THE WORLD OF LIFE 

us hope that the twentieth century will see the rise of a truer 
religion, a purer Christianity; that the conscience of our 
rulers will no longer permit a single man, woman, or child to 
have its life shortened or destroyed by any preventable cause, 
however profitable the present system may be to their employ- 
ers; that no one shall be allowed to accumulate wealth by the 
labour of others unless and until every labourer shall have re- 
ceived sufficient, not only for a bare subsistence, but for all the 
reasonable comforts and enjoyments of life, including ample 
recreation and provision for a restful and happy old age. 
Briefly, the support of the labourers without any injury to 
health or shortening of life should be a first charge upon the 
products of labour. Every kind of labour that will not bear 
this charge is immoral and is unworthy of a civilised com- 
munity. 

The Teaching of the Geological Record 

But this is a digression. Let us now return to a consid- 
eration of the main features of the course of life-development. 

The first point to w^hich our attention may be directed is, 
that the necessary dependence of animal life upon vegetation 
is the cause of some of the most prominent and perhaps the 
most puzzling features of the early life-world as presented to 
us by the geological record. In the Palaeozoic age we already 
meet with a very abundant and very varied aquatic life, in 
which all the great classes of the animal kingdom — sponges, 
zoophytes, echinoderms, worms, Mollusca, and vertebrates — 
were already fully differentiated from each other as we now 
find them, and existed in considerable variety and in gi'eat 
numbers. It is quite possible that the seas and oceans of those 
remote ages were nearly as full of life as they are now, though 
the forms of life were less varied and generally of a lower type. 
But, at the same time, the animal life of the land was very 
scanty, the only vertebrates that occupied it being a few Am- 
phibia and archaic reptiles. There were, however, a consid- 
erable number of primitive centipedes, spiders, Crustacea, and 



EXTENSIONS OF DARWINISM ;J03 

even true insects, the latter having already become specialised 
into several of our existing orders. All these occur either in 
the Coal formation of Europe or the Devonian rocks of North 
America, which seems to imply that when land-vegetation first 
began to cover the earth a very long period elapsed before any 
correspondingly abundant animal life was develo])ed ; and this 
W'as what we, should expect, because it would be necessary for 
the former to become thoroughly established and developed 
into a sufficient variety of forms well adapted to all the dif- 
ferent conditions of soil and climate, in order that they might 
be able to resist the attacks of the larger plant-feeding animals, 
as well as the myriads of insects when these appeared. So 
far as we can judge, the vegetable kingdom was left to develop 
freely during the enormous series of ages comprised in the 
Devonian, Carboniferous, and Permian formations, to which 
we must add the gap between the latter and the Triassic — the 
first of the Secondary formations. By that time the whole 
earth had probably become more or less forest-clad, but with 
vegetation of a Ioav type mostly allied to our ferns and horse- 
tails, with some of the earliest ancestral forms of pines and 
cycads. 

In the succeeding Secondary era the same general type of 
vegetation prevailed till near its close ; but it was then every- 
where subject to the attacks of large plant-devouring reptiles, 
and under this new environment it must necessarilv have 
started on new lines of evolution tending towards those higher 
flowering plants which, throughout the Tertiary period, be- 
came the dominant type of vegetation. It seems probable that 
throughout the ages animal and vegetable life acted and re- 
acted on each other. The earliest luxuriant land-vegetation, 
that which formed the great coal-fields of the earth, was 
probably adapted to the physical environment alone, almost 
uninfluenced by the scanty animal life. Then reptiles and 
mammals were differentiated ; but the former increased more 
rapidly, being perhaps better fitted to live upon the early vege- 
tation and to survive in the heavy carbonated atmosphere. This 



304 THE WORLD OF LIFE 

in turn became more varied and better adapted to resist their 
attacks; and when the new type had become well established it 
quickly replaced the earlier forms ; and the highly specialised 
reptiles, unable to obtain sufficient nourishment from it, and 
being also subject to the attacks of Camivora of increasing 
power, and perhaps to some adverse climatic changes, quickly 
disappeared. Then came the turn of the Mammalia, the birds, 
and the more specialised insects, which, during this vast period, 
had been slowly developing into varied but always rather 
diminutive forms, the birds and mammals feeding probably 
on insects, roots, and seeds; but, in proportion as the reptiles 
disappeared, they were ready to branch out in various direc- 
tions, occupying the many places in nature left vacant by these 
animals, and thus initiated that wonderfully varied mam- 
malian life which throughout the whole Tertiary period occu- 
pied the earth's surface as completely, and almost as exclu- 
sively, as the reptiles had done during the middle ages of geo- 
logical time. 

The reactions of insects and flowers are universally ad- 
mitted, as are those between birds and fruits ; but the broader 
aspect of this reaction between animal and plant life as a 
whole has not, I think, received much attention. It does, 
however, seem to throw a glimmer of light on the very puz- 
zling facts of the vast development of Secondary reptilian 
life, the apparent arrest of development of mammals during 
the whole vast period, and the rapid and abundant outgrowths 
of the higher types both of plants and of Mammalia in the 
Tertiary age. 

The complete metamorphosis, broadly speaking, of both 
plant and animal life, on passing from the former to the lat- 
ter epoch, is most startling. Such a change was, however, ab- 
solutely essential, not only for the production of the higher 
Mammalia and intellectual man, but also to provide for the 
infinitely varied needs of man's material, moral, and aesthetic 
development. The immensely varied plant-group of phanero- 
gams has served to unlock for his service the myriad potenti- 



EXTENSIONS OF DARWINISM 305 

alities which lay hidden in protoplasm — the mysterious 
physical basis of all life. To this vast series of herbs and 
shrubs and forest-trees he owes most of the charms, the deli- 
cacies, and the refinements of his existence — almost all his 
fruits, most of his scents and savours, together with a large 
part of the delight he experiences in mountain and valley, 
forest, copse, and flower-spangled meadow, whieli everywhere 
adorn his earthly dwelling-place. 

To this we must add the infinitely varied uses to man of 
domestic animals, all supplied by the higher Mammalia or 
birds, while no single reptile has ever occupied or seems able 
to occupy the same place. We can only speculate on the part 
these have played in man's full development, but it must have 
been a great and an important one. The caring for cattle and 
sheep, the use of milk, butter, and cheese, and the weaving 
of wool and preparation of leather, must have all tended to 
raise him from the status of a beast of prey to that of the 
civilised being to whom some animals at all events became 
helpers and friends. And this elevation was carried a step 
further when the horse and the dog became the companions 
of his daily life, while fowls, pigeons, and various singing- 
birds added new pleasures and occupations to his home. That 
such creatures should have been slowly evolved so as to reach 
their full development at the very time when lie became able 
to profit by them must surely be accepted as additional evi- 
dence of a foreseeing mind which, from the first dawn of life 
in the vegetable and animal cells, so directed and organised 
that life, in all its myriad forms, as, in the far-off future, to 
provide all that was most essential for the growth and develop- 
ment of man's spiritual nature. 

In furtherance of this subject it would be necessary to put 
a definite bar to the persistence of a lower type which might 
have prevented or seriously checked the development of the 
higher forms destined to succeed them ; and this seems to have 
been done in the case of the ]^^esozoic reptiles by endowing 
them with such a limited amount of intelligent vitalitv as 



306 THE WORLD OF LIFE 

would not lead to its automatic increase under the stress of a 
long course of development, though accompanied by continual 
change of conditions and enormous increase in size. Hence 
the " ridiculously small brains " (as they have been termed) 
of these huge and varied animals. We may learn from this 
phenomenon, and the parallel case of the huge Dinocerata 
among the Tertiary mammals, that development of a varied 
form and structure through the struggle for existence does not 
necessarily lead to an increase in intelligence or in the size and 
complexity of its organ the brain, as has been generally as- 
sumed to be the case. 

If, as John Hunter, T. H. Huxley, and other eminent 
thinkers have declared, '' life is the cause, not the consequence, 
of organisation,'' so we may believe that mind is the cause, 
not the consequence, of brain development. The first implies 
that there is a cause of life independent of the organism 
through which it is manifested, and this cause must itself be 
persistent — eternal — life, any other supposition being es- 
sentially unthinkable. And if we must posit an eternal Life 
as the cause of life, we must equally posit an eternal Mind as 
the cause of mind. And once accept this as the irreducible 
minimum of a rational belief on these two great questions, 
then the whole of the argument in this volume falls into logical 
sequence. 

Life as a cause of organisation is as clearly manifested 
and as much a necessity in the plant as in the animal; but 
they are plainly different kinds (or degrees) of life. So 
there are undoubtedly different degrees and probably also dif- 
ferent kinds of mind in various grades of animal life. And 
as the life-giver must be supposed to cause the due amount 
and kind of life to flow or be dra^vn into each organism, from 
the universe of life in which it lives, so the mind-giver, in like 
manner, enables each class or order of animals to obtain the 
amount of mind requisite for its place in nature, and to or- 
ganise a brain such as is required for the manifestation of that 
limited amount of mind and no more. 



EXTEIsrSIO:N^S OF DARWINISM 307 

Thus and thus only, as it seems to mo, can we under- 
stand the raison d' etre of these small-brained animals. They 
were outgi'owths of the great tree of life for a temporary pur- 
pose, to keep doA\Ti the coarser vegetation, to supply animal 
food for the larger Carnivora, and thus give time for higher 
forms to obtain a secure foothold and a sullicient amount of 
varied form and structure, from which they could, when bet- 
ter conditions prevailed, at once start on those wonderful di- 
verging lines of advance which have resulted in the perfected 
and glorious life-world in the midst of which we live, or ought 
to live. 

This view of the purport, the meaning, and the higher func- 
tion of the gTcat and varied life-world brings us by a differ- 
ent route to what many of our better thinkers and teachers 
have tried to impress upon us — • that our great cities are the 
" wens,'' the disease-products of humanity, and that until they 
are abolished there can be no approach to a true or rational 
civilisation. 

This was the teaching of that true and far-seeing child of 
nature, William Cobbett; it is the teaching of all our greatest 
sanitarians ; it is the teaching of Nature herself in the com- 
parative rural and urban death-rates. Yet we have no legis- 
lator, no minister, who will determinedly set himself to put 
an end to the continued growth of these " wens " ; which are 
wholly and absolutely evil. I will, therefore, take this oppor- 
tunity of showing how it can be done. 

There is much talk now of what will and must be the 
growth of London during the next twenty or fifty years ; and 
of the necessity of bringing water from Wales to su})])ly the 
increased pojjulation. But where is the necessity ? Why pro- 
vide for a population which need never have existed, and 
whose coming into existence will be an evil and of no pos- 
sible use to any human beings but the landowners and specu- 
lators, who will make money by the certain injury of their 
fellow-citizens. If the House of Commons and the l>ondt»n 
County Council are not the bond-slaves of the landowners and 



308 THE WOELD OF LIFE 

speculators, they have only to refuse to allow any further 
water-supply to be provided for London except what now ex- 
ists, and London will cease to grow. Let every speculator have 
to provide water for and on his own estate, and the thing will 
be done — to the enormous benefit of humanity. 

The same thing can, I presume, be done by Parliament for 
any other growing town or city. It can justly say : '^ When 
you have not a gallon of polluted water in your town, and 
when its death-rate is brought down to the average standard 
of rural areas, we will reconsider the question of your further 
growth.'' By that time, probably, there will be no public de- 
mand for enlarging our " wens '' and a very strong and stem, 
one for their cure or their abolition. 



/ 



CHAPTER XIV 

BIRDS AND INSECTS : AS PROOFS OF AN OKGANISING AND 

DIRECTIVE LIFE-PRINCIPLE 

If we strip a bird of its feathers so that we can see its bodj- 
structure as it really is, it appears as the most ungainly and 
misshapen of living creatures ; yet there is hardly a bird but 
in its natural garment is pleasing in its form and motions, 
while a large majority are among the most beautiful in shape 
and proportions, the most graceful in their activities, and often 
the most exquisite and fascinating of all the higher animals. 
The fact is, that the feathers are not merely a surface-clothing 
for the body and limbs, as is the hairy covering of most mam- 
mals, but in the wing and tail-feathers form an essential part 
of the structure of each species, without which it is not a com- 
plete individual, and could hardly maintain its existence for 
a single day. The whole internal structure has been gradually 
built up in strict relation to this covering, so that every part 
of the skeleton, every muscle, and the whole of the vascular 
system for blood-circulation and aeration have been slowly 
modified in such close adaptation to the whole of the plumage 
that a bird without its feathers is almost as helpless as a mam- 
mal which has lost its limbs, tail, and teeth. 

Although birds are so highly organised as to rival mam- 
' mals in intelligence, while they surpass them in activity and 
in their high body -temperature, yet they owe this position to 
an extreme retrogressive specialisation resulting in the com- 
plete loss of the teeth, while the digits of the fore limb are re- 
duced to three, the bones of which are more or less united, and, 
though slightly movable, are almost entirely hidden under tho 
skin. 

The earliest fossil bird, the Arch^eopteryx, bad throe ap- 

301) 



310 THE WORLD OE LIFE 

parentlj free and movable digits on the fore limbs, each end- 
ing in a distinct claw ; while the two bones forming the fore- 
arm appear to have been also free and movable, so that the 
wing must have been much less compact and less effective for 
flight than in modern birds. This bird was about as large as 
a rook, but with a tail of twenty vertebra', each about half an 
inch long and bearing a pair of feathers, each four inches in 
length and half an inch broad, while the wing feathers were 
nearly twice as long. The almost complete disappearance of 
the unwieldy tail, with the fusing together of the wing-bones, 
must have gone on continuously from that epoch. In the 
Cretaceous period the long tail has disappeared, and the wing- 
bones are much more like those of living birds; but the jaws 
are still toothed. In the early Tertiary deposits bird-remains 
are more numerous, and some of the chief orders of modern 
birds seem to have existed, while a little later modern families 
and genera appear. 

The important point for our consideration here is that, in 
the very earliest of the birds yet discovered which still re- 
tained several reptilian characteristics, true feathers, both of 
wings and tail, are so clearly shown as to leave no doubt of 
their practical identity with those of living birds. 

It is therefore evident that birds with feathers began to be 
developed as early as (perhaps even earlier than) the mem- 
branous-winged reptiles (Pterodactyles), and that these two 
groups of flying vertebrates began on two opposite principles. 
The birds must have started on the principle of condensation 
and specialisation of the fore limb exclusively for flight by 
means of feathers ; the other by the extension of one reptilian 
digit to support a wing-membrane, while reserving the others 
probably for suspension, as in the case of the thumb of the 
bats. 

The Marvel and Mystery of Feathers 

Looking at it as a whole, the bird's wing seems to me 
to be, of all the mere mechanical organs of any living thing, 



PKOOIS OJ^^ OKGANiSi^'G Aili\D 311 

that ^vhicli most clearly implies the working out of a j^recon- 
ceived design in a new and apparently most complex and dilli- 
cult manner, yet so as to produce a marvellously successful re- 
sult. The idea worked out was to reduce the jointed bony 
framework of the wings to a compact minimum of size and 
maximum of strength in proportion to the muscular power 
employed ; to enlarge the breastbone so as to give room for 
greatly increased power of pectoral muscles; and to construct 
that part of the wing used in flight in sucli a manner as to 
combine great strength with extreme lightness and the most 
perfect flexibility. In order to produce this more perfect in- 
strument for flight the plan of a continuous membrane, as in 
the flying reptiles (whose origin was probably contcm})ora- 
neous with that of the earliest birds) and flying mammals, to 
be developed at a much later period, was rejected, and its placo 
was taken by a series of broad overlapping oars or vanes, 
formed by a central rib of extreme strength, elasticity, and 
lightness, with a web on each side made up of myriads of parts 
or outgrowth so wonderfully attached and interlocked as to 
form a self-supporting, highly elastic structure of almost in- 
conceivable delicacy, very easily pierced or ruptured by the 
impact of solid substances, yet able to sustain almost any 
amount of air-pressure without injury. And even when any 
part of this delicate web is injured by separating the adjacent 
barbs from each other, they are so wonderfully constructed that 
the pressure and movement of other feathers over them causes 
them to unite together as firmly as before ; and this is done 
not by any process of gro^vth, or by any adhesive exudation, 
but by the mechanical structure of the delicate hooked lamelhn 
of which they are composed. 

The two illustrations here given (Figs. lOS, lOD) show two 
of the adjacent fibre-like parts (barbs) of which the web of a 
bird's feather is composed, and which are most clearly shown 
in the wing-feathers. Tlie slender barbs or ribs of which the 
web of the feather is made up can be best understood by strip- 
ping off a portion of the wel) and separating two of the barbs 



312 



THE WOELD OE LIEE 



from the rest. With a good lens the structure of the barbs, 
with their delicate hooked barbules interlocking with the bent- 
out upper margins of the barbules beneath them, can be seen, 
as shown in the view and section here given. The barbs (B, 



Magnified View of the Barbs and Barbules forming the Web of a Bird's 

Wing-Feathers (X 50). 




Fig. 108. — 'View of a portion of two adjacent Barbs (B, B), looking from 
the Shaft towards the edge of the Feather. 

bd, distal barbules; bp, proximal barbules. 




Fig. 109. — Oblique Section through the Proximal Barbules in a plane par- 
allel to the Distal Barbules of the upper Figure. 
Letters as above ; 1, 2, 3, barbicels and hamuli of the ventral side of the distal 
barbule; 4, barbicels of the dorsal side of the same, without hamuli. 

(From Newton's Dictionary of Birds.) 



B in the figures) are elastic, homj plates set close together on 
each side of the midrib of the feather, and pointing obliquely 
outwards; while the barbules are to the barbs what the barbs 
are to the feather — excessively delicate horny plates, which 



PKOors OF oega:xising mind 313 

also grow obliquely outwards towards the tip of the barb. 
Laterally they touch each other with smooth, glossy surfaces, 
which are almost air-tight, yet allow whatever slight motions 
that may be required during use, while remaining interlocked 
with the barbules of the adjoining barb in the manner just de- 
scribed. They are the essential elements of the feather, on which 
its value both for flight and as a protective clothing depends. 
Even in the smallest wing- feathers they are probably a liundred 
thousand in number, since in the long wing-feather of a crane 
the number is stated by Dr. Hans Gadow to be more than a 
million. 

What are termed the " contour-feathers " are those that 
clothe the whole body and limbs of a bird with a garment of 
extreme lightness which is almost comj^letely impen-ious to 
either cold or heat. These feathers vary greatly in shape on 
different parts of the body, sometimes forming a dense velvety 
covering, as on the head and neck of many species, or de- 
veloped into endless variety of ornament. They fit and overlap 
each other so perfectly, and entangle so much air between 
them, that rarely do birds suffer from cold, except when un- 
able to obtain any shelter from violent storms or blizzards. Yet, 
as everv sino'le feather is movable and erectile, the whole bodv 
can be freely exposed to the air in times of oppressive heat, or 
to dry the feathers rapidly after bathing or after unusually 
heavy rain. 

A great deal has been written on the mechanics of a bird's 
flight, as dependent on the form and curvature of the feathers 
and of the entire wing, the powerful muscular arrangements, 
and especially the perfection of the adjustment by which dur- 
ing the rapid do^vn-stroke the combined feathers constitute a 
perfectly air-tight, exceedingly strong, yet highly elastic in- 
strument for flight ; while the moment the upward motion be- 
gins the feathers all turn upon their axes so that the air passes 
between them with hardly any resistance, and when they again 
begin the down-stroke close up nutomatically as air-tight as 
before. Thus the effective down-strokes follow each other so 



314 THE WOKLD OE LIFE 

rapidly that, together with the support given by the hinder 
portion of the wings and tail, the onward motion is kept up, 
and the strongest flying birds exhibit hardly any undulation in 
the course they are pursuing. But very little is said about the 
minute structure of the feathers themselves, which are what 
renders perfect flight in almost every change of conditions a 
possibility and an actually achieved result. 

But there is a further difference between this instrument 
of flight and all others in nature. It is not, except during 
actual growth, a part of the living organism, but a mechanical 
instrument which the organism has built up, and which then 
ceases to form an integral portion of it — is, in fact, dead mat- 
ter. Hence, in no part of the fully grown feather is there 
any blood circulation or muscular attachment, except as re- 
gards the base, which is firmly held by the muscles and ten- 
dons of the rudimentary hand (fore limb) of the bird. This 
beautiful and delicate structure is therefore subject to wear 
and tear and to accidental injury, but probably more than any- 
thing else by the continuous attrition during flight of dust- 
laden air, which, by wearing away the more delicate parts 
of the barbules, renders them less able to fulfil the various 
purposes of flight, of body-clothing, and of concealment, as well 
as the preservation of all those colours and markings which are 
especially characteristic of each species, and generally of each 
sex separately, and which, having all been developed under the 
law of utility, are often as important as structural characters. 
Provision is therefore made for the annual renewal of every 
feather by the process called moulting. The important wing- 
feathers, on which the very existence of most birds depends, 
are discarded successively in pairs at such intervals as to allow 
the new growth to be Avell advanced before the next pair are 
thrown off, so that the bird never loses its power of flight, 
though this may be somewhat impaired during the process. 
The rest of the plumage is replaced somewhat more rapidly. 

This regrowth every year of so complex and important a 
part of a bird's structure, always reproducing in every feather 



PROOFS OF OEGAKISIKG MIIS'J) 315 

the size and shape characteristic of the species, Avhile each of 
the often very diverse feathers grows in its right place, and re- 
produces the various tints and colours on certain parts of every 
feather which go to make up the characteristic colours, markings, 
or ornamental plumes of each species of bird, presents us with 
the most remarkable cases of heredity, and of ever-present ac- 
curately directed growth-power, to be found in the whole range 
of organic nature. 

The Nature of Growth 

The growth of every species of organism into a highly com- 
plex form, closely resembling one or other of its parents, is so 
universal a fact that, \vith most people, it ceases to excite won- 
der or curiosity. Yet it is to this day absolutely inexplicable. 
No doubt an immense deal has been discovered of the mech- 
anism of growth, but of the nature of the forces at work, or of 
the directive agencies that guide and regulate the forces, we 
have nothing but the vaguest hints and conjectures. All 
growth, animal or vegetable, has been long since ascertained to 
begin with the formation and division of cells. A cell is a 
minute mass of protoplasm, a substance held to be the physical 
basis of life. This is, chemically, the most complex substance 
known, for while it consists mainly of four elements — car- 
bon, hydrogen, nitrogen, and oxygen — it is now ascertained 
that eight other elements are always present in cells composed 
of it — sulphur, phosphorus, chlorine, potassium, sodium, 
magnesium, calcium, and iron. Besides these, six others are 
occasionally found, but are not essential constituents of pro- 
toplasm. These are silicon, fluorine, bromine, iodine, alumi- 
nium, and manganese.^ 

Protoplasm is so complex a substance, not only in the num- 
ber of the elements it contains, but also in the mode of their 
chemical combination, that it is quite beyond the reach of 
chemical analysis. It has been divided into throe groups of 
chemical substances — proteids, carbohydrates, and fats. The 

1 Verworu's General Physiology, p. 100. 



316 THE WOKLD OF LIFE 

first is always present in cells, and consists of five elements — 
carbon, hydrogen, sulphur, nitrogen, and oxygen. The two 
other groups of organic bodies, carbohydrates and fats, con- 
sist of three elements only — carbon, hydrogen, and oxygen, the 
carbohydrates forming a large proportion of vegetable products, 
the fats those of animals. These also are highly complex in 
their chemical structure, but being products rather than the 
essential substance of living things, they are more amenable 
to chemical research, and large numbers of them, including 
vegetable and animal acids, glycerin, grape sugar, indigo, 
caifeine, and many others, have been produced in the labora- 
tory, but always by the use of other organic products, not from 
the simple elements used by nature. 

The atomic structure of the proteids is, however, so wonder- 
fully complex as to be almost impossible of determination. 
As examples of recent results, haemoglobin, the red colouring 
matter of the blood, was found by Preyer in 1866 to be as 
follows — 

^eoo-tlgeo-^ 154-'^ ^1^3^179? 

showing a total of 1894 atoms, while Zinoffsky in 1855 found 
the same substance from horse's blood to be — 

C'7i2-tiii3o-'^ 214^245!' 6l^2> 

showing a total of 2301 atoms. Considering the very small 
number of atoms in inorganic compounds, and in the simpler 
vegetable and animal products, caffeine containing only 23 
(C7H7(CH3)N402), the complexity of the proteids will be 
more appreciated. 

Professor Max Verworu, from whose gTeat work on General 
Physiology the preceding account is taken, is very strong in 
his repudiation of the idea that there is such a thing as a 
'' vital force." He maintains that all the powers of life reside 
in the cell, and therefore in the protoplasm of which the cell 
consists. But he recognises a great difference between the 



PEOOFS OF OKGANISING MIND 317 

dead and the living cell, and admits that our knowledge of the 
latter is extremely imperfect. He enumerates many differ- 
ences between them, and declares that '' substances exist in liv- 
ing which are not to be found in dead cell-substance." He 
also recognises the constant internal motions of the living cell, 
the incessant waste and repair, while si ill preserving the highly 
complex cell in its integrity for indefinite periods; its resist- 
ance during life to destructive agencies, to which it is exposed 
the moment life ceases ; but still there is no '" vital force " — 
to postulate that would be unscientific. 

Yet in this highly elaborate volume of 600 closely printed 
pages, dealing with every aspect of cell-structure and physiol- 
ogy in all kinds of organisms, he gives no clue whatever to the 
existence of any directive and organising powers such as are 
absolutely essential to preserve even the unicellular organism 
alive, and which become more and more necessary as we pass 
to the higher animals and plants, with their vast complexity 
of organs, reproduced in every successive generation from 
single cells, which go through their almost infinitely elaborate 
processes of cell-division and recomposition, till the whole vast 
complex of the organic machinery ■ — the whole body, limbs, 
sense, and reproductive organs — are built up in all their per- 
fection of structure and co-ordination of parts, such as char- 
acterises every living thing ! 

Let us now recur to the subject that has led to this digres- 
sion — the feathers of a bird. We have seen that a full-gi'own 
wing-feather may consist of more than a million distinct parts 
— the barbules, which give the feather its essential character, 
whether as an organ of flight or a mere covering and heat-pre- 
server of the body. But these barbules are themselves highly 
specialised bodies with definite forms and surface-texture, 
attaching each one to its next lateral barbule, and, by a kind 
of loose hook-and-eye formation, to those of the succeeding 
barb. Each of these barbules must therefore be built up of 
many thousands of cells (probably many millions), differing 
considerably in form and powers of cohesion, in order to pro- 



318 THE WORLD OE LIFE 

cluce the exact strength, elasticity, and continuity of the whole 
web. 

Now each feather " grows/' as we say, out of the skin, each 
one from a small group of cells, which must be formed and 
nourished by the blood, and is reproduced each year to replace 
that which falls away at moulting time. But the same blood 
supplies material for every other part of the body — builds 
up and renews the muscles, the bones, the viscera, the skin, 
the nerves, the brain. What, then, is the selective or directing 
power which extracts from the blood at every point where 
required the exact constituents to form here bone-cells, there 
muscle-cells, there again feather-cells, each of which possesses 
such totally distinct properties ? And when these cells, or 
rather, perhaps, the complex molecules of which each kind of 
cell is formed, are separated at its special point, w^hat is the 
constructive power wdiich welds them together, as it were, in 
one place into solid bone, in another into contractile muscle, in 
another into the extremely light, strong, elastic material of the 
feather — the most unique and marvellous product of life ? 
Yet again, wdiat is the nature of the power which deteiToines 
that every separate feather shall always " grow " into its exact 
shape ? For no two feathers of the twenty or more which 
form each wing, or those of the tail, or even of the thousands 
on the whole body, are exactly alike (except as regards the 
pairs on opposite sides of the body), and many of these are 
modified in the strangest way for special purposes. Again, 
what directive a2:encv determines the distribution of the col- 
ouring matter (also conveyed by the blood) so that each feather 
shall take its exact share in the production of the whole pattern 
and colouring of the bird, which is immensely varied, yet 
always symmetrical as a whole, and has always a purpose, 
either of concealment, or recognition, or sexual attraction in 
its proper time and place ? 

Xow, in none of the volumes on the physiology of animals 
that I have consulted can I find any attempt whatever to 
grapple Avith this fundamental question of the directive power 



PROOFS OF ORGANISING MIND 319 

that, in every case, first secretes, or as it were creates, out of 
the protoplasm of the blood, special molecules adapted for the 
2:>roductiou of each malcrial — bone, muscle, nerve, skin, hair, 
feather, etc. etc., — carries these molecules to the exact part 
of the body where and when they are required, and brings into 
play the complex forces that alone can 1)uild up with (ri-eat 
rapidity so strangely complex a structure as a feather adapted 
for flight. Of course the difficulties of conceiving how this 
has been and is being done before our eyes is nearly as great 
in the case of any other specialised part of the animal body; 
but the case of the feathers of the bird is unique in many ways, 
and has the advantage of being wdiolly external, and of being 
familiar to every one. It is also easily accessible for examina- 
tion either in the living bird or in the detached feather, which 
latter offers wonderful material for microscopic examination 
and study. To myself, not all that has been written about 
the properties of protoplasm or the innate forces of the cell, 
neither the physiological units of Herbert Spencer, the pan- 
genesis hypothesis of Darwin, nor the continuity of the germ- 
plasm of Weismann, throw the least glimmer of light on this 
great problem. Each of them, especially the last, help us to 
realise to a slight extent the nature and laws of heredity, but 
leave the great problem of the nature of the forces at work in 
growth and reproduction as mysterious as ever. IModern 
physiologists have given us a vast body of information on the 
structure of the cell, on the extreme complexity of the proc- 
esses which take place in the fertilised ovum, and on the exact 
nature of the successive changes up to the stage of maturity. 
But of the forces at work, and of the power which guides those 
forces in building up the whole organ, we find no enlighten- 
ment. They will not even admit that any such constructive 

guidance is required ! 
* 

A Physiological Allegory 

For an imaginary parallel to this state of tliinirs, let us 
suppose some race of intellia'cut beings wlio have tlie j)Ower 



320 THE WORLD OF LIFE 

to visit the earth and see what is going on there. But their 
faculties are of such a nature that, though they have perfect 
perception of all inanimate matter and of plants, they are 
absolutely unable either to see, hear, or touch any animal living 
or dead. Such beings would see everywhere matter in motion, 
but no apparent cause of the motion. They would see dead 
trees on the ground, and living trees being eaten away near 
the base by axes or saws, which w^ould appear to move spon- 
taneously; they would see these trees gradually become logs 
by the loss of all their limbs and branches, then move about, 
travel along roads, float down rivers, come to curious machines 
by which they are split up into various shapes ; then move 
away to where some great structure seems to be growing up, 
where not only wood, but brick and stone and iron and glass 
in an infinite variety of shapes, also move about and ultimately 
seem to fix themselves in certain positions. Special students 
among these spirit-inquirers would then devote themselves to 
follow back each of these separate materials — the wood, 
the iron, the glass, the stone, the mortar, etc. — to their sep- 
arate sources; and, after years thus spent, would ultimately 
arrive at the great generalisation that all came primarily out 
of the earth. They would make themselves acquainted with 
all the physical and chemical forces, and would endeavour to 
explain all they saw by recondite actions of these forces. They 
would argue that what they saw was due to the forces they 
had traced in building up and modifying the crust of the 
earth ; and to those who pointed to the result of all this ^' mo- 
tion of matter " in the finished product — the church, the 
mansion, the bridge, the railway, the huge steamship or cotton 
factory or engineering works — as positive evidence of design, 
of directive power, of an unseen and unknown mind or minds, 
they would exclaim, " You are wholly unscientific ; we know 
the physical and chemical forces at work in this curious world, 
and if we study it long enough we shall find that known forces 
will explain it all." 

If we suppose that all the smaller objects, even if of the 



PEOOFS OF ORGANISING MIXD :]21 

same size as ourselves, enn only he seen by microscopes, and 
that with improved instruments the various tools we use, as 
well as our articles of furniture, our food, and our tahlc-fit tings 
(knives and forks, dishes, glasses, etc., and even our watches, 
our needles and pins, etc.) become perceptible, as well as the 
food and drinks which are seen also to move about and dis- 
appear; and when all this is observed to recur at certain def- 
inite intervals every day, there woidd be great jubihition over 
the discovery, and it would be loudly proclaimed that with 
still better microscopes -all would be explained in terms of 
matter and motion ! 

That seems to me very like the position of modern physiol- 
ogy in regard to the processes of the growth and development 
of living things. 

Insects and their Metamorphosis 

We now have to consider that vast assemblage of small 
winged organisms constituting the class Insect a, or insects, 
which may be briefly defined as ringed or jointed (annuluse) 
animals, with complex mouth-organs, six legs, and one or two 
pairs of wings. They are more numerous in species, and 
perhaps also in individuals, than all other land-animals put 
together; and in either their larval or adult condition supi)ly 
so large and important a part of the food of birds, that the 
existence of the latter, in the variety and abundance we now 
behold, may be said to depend upon the former. 

The most highly developed and the most abundant of the 
insect tribes are those which possess a perfect metamorphosis, 
that is, which in their larval state are the most comi)letely 
unlike their perfect condition. They comprise the great orders 
Lepidoptera (butterflies and moths), Coleojitera (beetles), 
Hymenoptera (bees, ants, etc.), and Diptc^-a (two-winged 
flies), the first and last being those which are perha])s the most 
important as bird-food. In all these orders the eggs produce 
a minute aTub, maggot, or caterpillar, a- they are variously 
called, the first havino- a distinct head but no legs, the second 



322 THE WORLD OF LIFE 

neither head nor legs, while the third have both head and legs, 
and are also variously coloured, and often possess spines, horns, 
hair-tufts, or other appendages. 

Every one knows that a caterpillar is almost as different 
from a butterfly or moth in all its external and most of its 
internal characters, as it is possible for any two animals of 
the same class to be. The former has six short feet with 
claws and ten fleshy claspers; the latter, six legs, five- jointed, 
and with subdivided tarsi; the foi-mer has simple eyes, biting 
jaws, and no sign of wings; the latter, large compound eyes, 
a spiral suctorial mouth, and usually four large and beauti- 
fully coloured wrings. Internally the whole muscular system 
is quite different in the two forms, as well as the digestive 
organs, while the reproductive parts are fully developed in 
the latter only. The transformation of the larva into the per- 
fect insect through an intervening quiescent pupa or chrysalis 
stage, lasting from a few days to several months or even years, 
is substantially the same process in all the orders of the higher 
insects, and it is certainly one of the most marvellous in the 
whole organic world. The untiring researches of modern ob- 
servers, aided by the most perfect microscopes and elaborate 
methods of preparation and observation, have revealed to us 
the successive stages of the entire metamorphosis, which has 
thus become more intelligible as to the method or succession 
of stages by which the transformation has been effected, though 
leaving the fundamental causes of the entire process as mys- 
terious as before. Years of continuous research have been 
devoted to the subject, and volumes have- been Avritten upon it. 
One of the most recent English writers is Mr. B. Thompson 
Lowne, F.E.C.S., who has devoted about a quarter of a cen- 
tury to the study of one insect — the common blow-fly — on 
the anatomy, physiology, and development of w^hich he has 
published an elaborate work in two volumes dealing with every 
part of the subject. He considers the two-winged flies to be 
the highest development of the insect-type ; and though they 
have not been so popular among entomologists as the Coleoptera 



PEOOFS OF ORGAXISLXG MLXl) 






and Lepidoptera, he believes them to be the most nnmenjus in 
species of all the orders of insects. 1 will now endeavour to 
state in the fewest words possible tbe general results of his 
studies, as well as those of the students of the other orders 
mentioned, which are all in substantial agreement. 

In those insects which have the least comi)lete metamorpho- 
sis — the cockroaches — the young emerge from the egg with 
the same general form as the adult, but with rudimentarv 
wings, the perfect wrings being acquired after a succession of 
moults. These seem to be the oldest of all insects, fossilised 
remains of a similar type being found in the Silurian forma- 
tion. Locusts and Hemiptera are a little more advanced, and 
are less ancient geologically. Between these and the four 
orders with complete metamorphosis there is a great gap, which 
is not yet bridged over by fossil forms. But from a minute 
study of the development of the egg, which has been examined 
almost hour by hour from the time of its fertilisation, the 
conclusion has been reached, that the great difference we now 
see between the larva and imago (or perfect insect) has been 
brought about by a double process, simultaneously going on, 
of progression and retrogression. Starting from a form some- 
what resembling the cockroach, but even lower in the scale of 
organisation, the earlier stages of life have become more sim- 
plified, and more adapted (in the case of Lepidoptera) for 
converting living tissues of plants into animal protoplasm, thus 
laying up a store of matter and energy for the development 
of the perfect insect ; wdiile the latter form has become so fully 
developed as to be almost independent of food-supply, by being 
ready to carry out the functions of reproduction within a few 
days or even hours of its emergence from the pupa case. 

At first this retrogression of the first stage of growth towards 
a simple feeding machine took place at the period of the suc- 
cessive moults, but it being more advantageous to hav(^ the 
larva stage wholly in the form best adaptcMl for the storing up 
of living protoplasm, the retrogressive variations became stop 
by step earlier, and at length occurred within the egg. At 



324 THE WOELD OF LIFE 

this early period certain rudiments of wings and other organs 
are represented by small groups of minute cells termed by 
Weismann imaginal discs, which were determined by him to 
be the rudiments of the perfect insect. These persist un- 
changed through the whole of the active larval stage ; but as 
soon as the final rest occurs preliminary to the last moult, a 
most wonderful process commences. The whole of the internal 
organs of the larva — muscles, intestines, nerves, respiratory 
tubes, etc. — ■ are gradually dissolved into a creamy pulp ; and 
it has further been discovered that this is effected through the 
agency of white blood-corpuscles or phagocytes, which enter 
into the tissues, absorb them, and transform them into the 
creamy pulp referred to. This mass of nutritive pulp thence- 
forth serves to nourish the rapidly growing mature insect, with 
all its wonderful complication of organs adapted to an entirely 
new mode of life. 

There is, I believe, nothing like this complete decomposi- 
tion of one kind of animal structure and the regrowth out of 
this broken-down material — which has thus undergone decom- 
position of the cells, but not apparently of the protoplasmic 
molecules — to be found elsewhere in the whole course of 
organic evolution; and it introduced new and tremendous dif- 
ficulties into any mechanical or chemical theory of growth and 
of hereditary transmission. We are forced to suppose that the 
initial stages of every part of the perfect insects in all their 
wonderful complexity and diversity of structure are formed 
in the egg, and that during the subsequent raj^idly growing 
development of the larva they remain dormant ; then, that the 
whole structure of the fully grown larva is resolved into its 
constituent molecules of living protoplasm, still without the 
slightest disturbance of the rudimentary germs of the perfect 
insect, which at a special moment begin a rapid course of de- 
velopmental growth. This growth has been followed, step by 
step through all its complicated details, by ^Ir. Lowne and 
many other enthusiastic workers , but I will call attention here 



PEOOFS OF ORGANISING AilXD 325 

only to the special case of the Lepidoptera, l)ocnu>c these are 
far more popuLarly known, and the special feature which dis- 
tinguishes them from most other insects is fauiiliar to every 
one, and can be examined by means of a good pocket lens or 
microscope of moderate power. I allude, of course, !<• the 
•wonderful scales Avhich clothe the wings of most buttcrllics 
and moths, and which produce the brilliant colours and in- 
finitely varied patterns with which they are adorned. (){' 
conrse, the still more extensive order of the C(deoptera 
(beetles) present a similar phenomenon in the cuh^urs and 
markings of their wing-cases or elytra, and what is said of 
the one order will apply broadly to the other. 

The wings of butterflies can be detected in very young 
caterpillars when they are only one-sixth of an inch long, as 
small out-foldings of the inner skin, which remain unchanged 
while the larva is growing; but at the chrysalis (or pupa) stage 
the wings ex^iand to about sixty times their former area, and 
the two layers of cells composing them then become visible. 
At this time they are as transparent as glass ; but two ur three 
weeks before emergence of the imago they become opaque white, 
and a little later dull yellow' or drab; twenty-four hours later 
the true colours begin to appear at the centre of each wing. 
It is during the transparent stage that the scales begin tf> Ix* 
formed as minute, bag-like sacks filled with protoplasm ; the 
succeeding whiteness is caused by the protoplasm being with- 
drawn and the sacks becoming filled with air. The pupal 
blood then enters them, and from this the colouring matter is 
secreted. The scales are formed in parallel lines along ridges 
of the corrugated wing membrane. The more bfilliani enloui-s 
seem to be produced from the dull yellow ]ugment by cheinical 
chanc'es Avhich occur within the scales. A few davs belore 
emergence the scales become fullv jxrown, as hii^hlv coniph.'X 
structures formed of parallel rows of minute cells, each -cale 
with a basal stem which enters a pocket of the skin or mem- 
brane, which pockets send out root^ wlii(^h seem to penetrate 



326 THE WOKLD OF LIFE 

through the skin.^ Another complication is the fact that the 
wonderful metallic colours of so many butterflies are not caused 
by pigments, but are ^' interference colours " produced by fine 
striae on the surface of the scales. Of course, where eye-spots, 
fine lines, or delicate shadings adorn the wings, each scale must 
have its own special colour, something like each small block 
in a mosaic picture. 

As this almost overwhelming series of changing events passes 
before the imagination, we see, as it were, the gradual but 
perfectly orderly construction of a living machine, which at 
first appears to exist for the sole purpose of devouring leaves 
and building up its own wonderful and often beautiful body, 
thereby changing a lower into a higher form of protoplasm. 
Its limbs, its motions, its senses, its internal structure, are all 
adapted to this one end. Wlien fully grown it ceases to feed, 
prepares itself for the great change by various modes of con- 
cealment — in a cocoon, in the earth, by suspension against 
objects of similar colours, or which it becomes coloured to 
imitate — rests awhile, casts its final skin, and becomes a 
pupa. Then follows the great transformation scene, as in the 
blow-fly. All the internal organs which have so far enabled 
it to live and grow — in fact, the whole body it has built up, 
with the exception of a few microscopic groups of cells — be- 
come rapidly decomposed into its physiological elements, a 
structureless, creamy but still living protoplasm ; and when 
this is completed, usually in a few days, there begins at once 
the building up of a new, a perfectly different, and a much 
more highly organised creature both externally and internally 
— a creature comparable in organisation with the bird itself, 
for which, as we have seen, it appears to exist. And, in the 
case of the Lepidoptera, the wings, far simpler in construc- 
tion than those of the bird, but apparently quite as well adapted 
to its needs, develop a more or less complete covering of minute 

1 This description is from Mr. A. G. Mayer's paper on the Development 
of the Wing Scales of Butterflies and Moths (Bull. Mus. Comp. Zool. Harv. 
Coll., June 1896), so far as I can give it in a verv condensed abstract. 



PEOOFS OF OKGA.XISIXG Ail.XD 327 

scales, whose chief or only function aijpears tu be tu paint 
them with all the colours and all tlie glittering reflections of 
the animal, the vegetable, and the mineral kingdoms, to an 
equal if not a greater extent than in the case of the birds them- 
selves. The butterflies, or diurnal Le])idoi)tera alone, not only 
present us with a range of colour and pattern and of metallic 
brilliancy fully equal (probably superior), to that of l)irds, 
but they possess also in a few cases and in distinct families, 
changeable opalescent hues, in which a pure crimson, or blue, 
or yellow pigment, as the incidence of light varies, changes 
into an intense luminous opalescence, sometimes resembling a 
brilliant phosphorescence more than any metallic or mineral 
lustre, as described in the next chapter. 

And what renders the wealth of coloration thus produced 
the more remarkable is, that, unlike the feathers of birds, tlic 
special organs upon which these colours and patterns are dis- 
played are not functionally essential to the insect's existence. 
They have all the appearance of an added superstructure to 
the wing, because in this way a greater and more brilliant 
display of colour could be produced than even upon the ex- 
quisite plumage of birds. It is true that in some cases, these 
scales have been modified into scent-a'lands in the males of 
some butterflies, and perhaps in the females of some moths, 
but otherwise they are the vehicles of colour alone; and though 
the diversity of tint and pattern is undoubtedly useful in a 
variety of ways to the insects themselves, yet it is so almost 
wholly in relation to higher animals and not to their own kind, 
as I have already explained in Cluipter IX. It is generally 
admitted that insects with compound eyes possess imperfect 
vision, and their actions seem to show that they take little 
notice of distant objects, except of lights at night, and only 
perceive distinctly what is a few inches or a few feet from 
them; while there is no proof tliat they recognise what we term 
colour unless as a greater or less amount of light. 

But as regards the effect of the shading and coloration of 
insects upon the higher animals, who are ahuo^t always their 



328 THE WOELD OF LIFE 

enemies, there is ample evidence. Almost all students of the 
subject admit that the markings and tints of insects often 
resemble their environment in a remarkable manner, and that 
this resemblance is protective. The eye-like markings, either 
on the upper or under surfaces, are often seen to be imitations 
of the eyes of vertebrates, when the insect is at rest, and this 
also is protective. The brilliant metallic or phosphorescent 
colours on the wings of butterflies may serve to distract ene- 
mies from attacking a vital part, or, in the smaller species 
may alarm the enemy by its sudden flash with change of posi- 
tion. But while the colours are undoubtedly useful, the mode 
of producing them seems unnecessarily elaborate, and adds a 
fresh complication in the way of any mechanical or chemical 
conception of their production. 



CHAPTER XV 

GENEBAL ADAPTATIONS OF PLANTS, ANIMAI.S, AND MAN 

The adaptations of plants and animals, more especially as 
regards the cross-fertilisation of flowers by insects, forms a 
very important part of Darwin's work, and has been fully 
and popularly elaborated since by Grant Allen, Sir John Lub- 
bock (now Lord Avebury), Hermann ^1 tiller, and many other 
writers. I have also myself given a general account of the 
whole subject both in my Tropical Xature, and my Darwin- 
ism; but as there are some points of importance which, 1 be- 
lieve, have not yet been discussed, and as the readers of this 
volume may not be acquainted with the vast extent of the evi- 
dence, I will here give a short outline of the facts before 
showing how it bears upon the main argument of the present 
work. 

Another reason why it is necessary to recapitulate the evi- 
dence is that those w^hose knowledge of this subject is derived 
from having read the Origin of Species only, can have no 
idea whatever of the vast mass of observations the author of 
that work had even then collected on the subject, but found 
it impossible to include in it. He there only made a few 
general, and often hypothetical, references both to the facts 
of insect- fertilisation, and to the purpose of cross-fertilisation. 
On the latter point he makes this general statement: " 1 have 
come to this conclusion (that flowers are coloured to attract 
insects) from finding it an invariable rule that when a flower 
is fertilised bv the wind it never has a ciailv-coloured ('or«)lla.'' 
Then a few lines farther on he advei'ts to beautifullv coloured 
fruits and says: "But the beauty servers merely as a guide to 
birds and beasts, in order tliat the fruit may be devoured and 
the matured seed disseminated: T infer that this is the case 

"■20 



330 THE WORLD OF LIFE 

from having as yet found no exception to the rule that seeds 
are always thus disseminated when embedded within a fruit 
of any kind if it be coloured of any brilliant tint." ^ 

Such general statements as those here quoted do not make 
much impression. The astonishment and delight of botanists 
and plant-lovers can, therefore, be imagined when, a few years 
later, by his book on the Fertilisation of Orchids by Insects, 
and his papers on the Different Forms of Flowers in the prim- 
rose, flax, lythrum, and some others ; he opened up a vast new 
world of wonder and instruction which had hitherto remained 
almost unnoticed. These were followed up by his volumes 
on The Effects of Cross- and Self -Fertilisation (in 1876), 
and by that on Different Forms of Flowers on Plants of the 
same Species (in 1877) giving the result of hundreds of care- 
ful experiments made by himself during many years, serv'ing 
as the justification for the few general observations as regards 
flowers and insects, which form the only reference to the sub- 
ject in the Origin of Species. 

The facts now admitted to be established by these various 
researches are: (1) that crosses between different individuals 
of the same species, either constantly or occasionally, are ben- 
eficial to the species by increasing seed-production and vigour 
of growth; (2) that there are innumerable adaptations in 
flowers to secure or facilitate this cross-fertilisation; (3) that 
all irregular flowers — Papilionacese, Labiates, Schrophulari- 
acese, Orchidese, and others — have become thus shaped to facil- 
itate cross-fertilisation. Darwin's general conclusion, that 
" nature abhors perpetual self-fertilisation," has been much 
criticised, but chiefly by writers who have overlooked the term 
" perpetual." He has also shown how the wonderful variety 
in form and structure, and the beauty or conspicuousness of 
the colours of flowers, can all be readily explained, on this 
theory, through the agency of variation and natural selection, 
while by no other theory is any real and effective explanation 
possible. But besides these there are very numerous other 

1 Origin of Species, 6th edition, p. 161. 



GEXEKAL ADAPTATIOXS 331 

adaptations in flowers to secure them from injurious insects 
or from the effects of rain or wind in damaging the pollen 
or the stigmas, as beautifully shown in Kerncr's very inter- 
esting volume on Flowers and their Unhidden Guests — a 
book that forms an admirable sequel to Darwin's works, and 
is equally instructive and interesting. 

Of late years writers wdio are very imperfectly acquainted 
wdth the facts proclaim loudly that Darwin's views are dis- 
proved, on account of some apparent exceptions to the general 
conclusions he has reached. Two of these mav he here noticed 
as illustrative of the kind of opposition to which Darwinism 
is exposed. The bee-orchis of our chalky downs, though con- 
spicuously coloured and with a fully-developed labellum, like 
the majority of its allies wdiich are cross-fertilised by insects, 
yet fertilises itself and is never visited by insects. This has 
been held to show that Darwin's views must be erroneous, 
notwithstanding the enormous mass of evidence on which they 
are founded. But a further consideration of the facts shows 
that they are all in his favour. In the south of Europe, while 
the bee-orchis is self-fertilised as in England, several allied 
species are insect-fertilised, bnt they rarely produce so many 
seed-capsules as ours; but, strange to say, an allied species 
(OpJirys scolopax) is in one district fertilised by insects only, 
while in another it is self-fertilised. Again, in Portugal, 
w^here many species of Ophrys are found, very few of the 
flowers are fertilised and very few ripe seed-ca])snles are pro- 
duced. But owing to the great number of seeds in a eapsuU', 
and their easy dispersal by wind, the plants are ahnn(hint. 
These and many other facts show that tor some unknown 
cause, orchises which are exclusively insect-fertilised, are liable 
to remain unfertilised, and when that is the rase it becomes 
advantageous to the species to be able to f(M*tilise itself, and 
this has occurred, partially in many species, and (•(•mpletely 
in our bee-orchis. 

I may remark here llint lhe name " l>ee-orchis " Is mislead- 
ing, as the flower does nol resemble any of our bee-. But the 



332 THE WORLD OE LIFE 

very closely allied '^ spider orchises " resemble spiders mucli 
more closely. It occurs to me, therefore, that the general 
resemblance to bee or spider may occasionally prevent the 
flowers being eaten off by sheep or lambs, to Avhom even spiders 
on their noses or lips would be disagreeable. 

Mr. Henry O. Forbes observed, in Sumatra, that many trop- 
ical orchids with show^y flowers, wdiich were perfectly adapted 
for insect-fertilisation, yet produced very few seed-capsules, 
and in many cases none. Yet the great abundance of seeds, 
as fine as dust, in a single capsule, together with the long life 
of most orchids, is quite sufficient, in most cases, to preserve 
the various species in considerable abundance. When, how- 
ever, there is any danger of extinction the great variability of 
orchids, which at first enabled them to become so highly spe- 
cialised for insect-fertilisation, also enables them (in some 
cases) to return to self-fertilisation as in our bee-orchis. 
Should this continuous self -fertilisation at length lead to a weak 
constitution, then, occasional variations serving to attract in- 
sects by nectar or in other ways, with minute alterations of 
structure may again lead to fertilisation by insects. 

The other popular objection recently made to Darwin's views 
on the origin of the flowers is, that the colours and shapes of 
flowers are often such as to deter herbivorous animals from 
eati-ng them, and that this is the main or the only reason why 
flowers are so conspicuous. The special case supposed to prove 
this is that some buttercups are not eaten by cattle because 
they are acrid or poisonous, and that the bright yellow colour 
is a warning of inedibility. 

Even if these statements were wdiolly correct they would not 
in the least affect the general proposition that all conspicuous 
flowers attract insects which do actually cross-fertilise them. 
But, in the first place, there is much difference of opinion as 
to the inedibility of buttercups by cattle; and, in the second, 
our three most common yellow buttercups (Banunculus acris, 
R. repens, and R. huJhosus) are so constructed that they can 
be cross-fertilised by a great variety of insects, and as a mat- 



GENERAL ADAPTATIONS 



O '> o 



ter of fact are so fertilised. IT. Miillcr grouped those lliroe 
species together, as the same insects visit them all, and lie 
found that thej were attractive to no less than sixty diilerent 
species, including 23 flies, 11 beetles, 2-1 bees, wasps, etc., and 
5 butterflies. 

Any readers who are not satisfied with Darwin's own state- 
ments on this subject should examine :\Iiill(M''s Fcrtili-atinn 
of Elowers (translated by D'Arcy W. Thonii)son), in whirh 
details are given of the fertilisation of abuut 100 species of 
alpine plants by insects, while a General "Retrospect gives a 
most valuable summary of the conclusions and teadiings on 
the whole subject. As regards the general question of the u^^ 
and purposes of colour in nature the late Grant Allen's inter- 
esting and philosophical work on The Colour Sense >hnuld bo 
studied. Any one who does so will be satisfied of the general 
truth of Darwin's doctrines though there are a few errors in 
the details. As an example of the fascinatinjr stvle of the 
book I will quote the following paragraph comparing insect- 
agency with that of man in modifving and beautit'vinfr the 
face of nature. After describing the great alterations man 
has made, and the large areas he has modified for his own 
purposes, the author thus proceeds : 

"But all these alterations are mere surface scratches coniparod 
with the immense revolution wrought in the features of nature l\v 
the unobtrusive insect. Half the flora of tlie earth has taken the 
imprint of his likes and his necessities. While man has only tilK'd 
a few level plains, a few great river-valleys, a few peninsular moun- 
tain slopes, leaving the vast mass of earth unloudied hy liis hand, 
the insect has spread himself over every land in a thousand sliapes, 
and has made the whole flowering creation sul)servient to liis daily 
wants. His buttercup, his dandelion, and his meadow-sweet grow- 
thick in every English field. TTis thyme elothes the hill-side: his 
heather purples the bleak grey moorland. HiLrh up among the 
Alpine heights his gentian spreads itsi'lf in lakes of blue: amid 
the snows of the Himalayas his rhododendrons gleam with crimson 
light. The insect has thus turned the whole surface of the eartli 



334 THE WORLD OF LIFE 

into a boundless flower-garden, which supplies him from year to 
year with pollen or honey, and itself in turn gains perpetuation by 
the baits it offers for his allurement." 

Although I wholly agree with my lamented friend in attrib- 
uting the origin and development of flowers to the visits of 
insects, and the consequent advantage of rendering many spe- 
cies of flowers conspicuous and unlike others flowering at the 
same time, thus avoiding the waste and injury of the frequent 
crossing of distinct species, yet I do not consider that the 
whole of the phenomena of colour in nature is thereby ex- 
plained. 

In my book on Tropical E'ature I devoted two chapters to 
the Colours of Animals and Plants, and I opened the discussion 
with the following remarks, which indicate my present views 
on the subject. I will, therefore, give a few passages here: 

" There is probably no one quality of natural objects from which 
we derive so much pure intellectual enjoyment as from their col- 
ours. The heavenly blue of the firmament, the glowing tints of 
sunset, the exquisite purity of the snowy mountains, and the end- 
less shades of green presented by the verdure-clad surface of the 
earth, are a never-failing source of pleasure to all who enjoy the 
inestimable gift of sight. Yet these constitute, as it were, but the 
frame and background of a marvellous and ever-changing picture. 
In contrast with these broad and soothing tints, we have presented 
to us, in the vegetable and animal worlds, an infinite variety of 
objects adorned with the most beautiful and the most varied hues. 
Flowers, insects, and birds are the organisms most generally orna- 
mented in this way; and their symmetry of form, their variety of 
structure, and the lavish abundance with which they clothe and 
enliven the earth, cause them to be objects of universal admiration. 
The relation of this wealth of colour to our mental and moral na- 
ture is indisputable. The child and the savage alike admire the 
gay tints of flower, bird, and insect; while to many of us their 
contemplation brings a solace and enjoyment which is wholly ben- 
eficial. It can then hardly excite surprise that this relation was 
long thought to afford a sufficient explanation of the phenomena 



GENERAL AD.U^TATIOXS 335 

of colour in nature, and this received great support from the dilTi- 
culty of conceiving any other use or meaning in the colours with 
which so many natural objects are adorned. Why should the 
homely gorse be clothed in golden ruiiiiuiit, and the prickly cactus 
be adorned with crimson bells? Why sliould our fields be gay with 
buttercups, and the heather-clad mountains be clad in purple robes? 
Why should every land produce its own peculiar floral gems, and 
the alpine rocks glow with beauty, if not for the contemplation and 
enjoyment of man? What could be the use to the butterfly of 
its gaily-painted wings, or to the humming-bird of its jewelled 
breast, except to add the final touches to a world-picture calculated 
at once to please and to refine mankind? And even now, with all 
our recently acquired knowledge of this subject, who shall say 
that these old-world views were not intrinsically and fundamentally 
sound; and that although we now know that colour has * uses ' 
in nature that we little dreamt of, yet the relations of those colours 
— or rather of the various rays of light — to our senses and emo- 
tions may not be another, and more important use which they sub- 
serve in the great system of the universe ? " 

The above passage was written more than forty years ago, 
and I now feel more deeply than ever that the concluding 
paragraph expresses a great and fundamental truth. Although 
in the paragraph succeeding that which I have quoted from 
Grant Allen's book, he refers to my view (stated above) as 
being '' a strangely gratuitous hypothesis," I now propose to 
give a few additional reasons for thinking it to be subr^tantially 
correct. 

The first thing to be noticed is, that the insects whose per- 
ceptions have led to the production of variously coloured flowers 
are so very widely removed from all the higher animals (birds 
and mammals) in their entire organisation that we have no 
right to assume in them an identity, or even a similarity, of 
sensation with ourselves. That they see is certain, but that 
their sensation of sight is the sanio ns our own. or even at all 
closely resembling it, is highly improbable Still niorc improb- 
able is it that their perception of oolour i< the same as ours, 
their organ of sight and their whole nervous system being so 



336 THE WORLD OF LIFE 

very different, and the exact nature of their senses being un- 
known. Even a considerable percentage of men and women 
are more or less colour-blind, yet some diversity of colour is 
perceived in most cases. The purpose of colour in relation 
to insects is that they should distinguish between the colours 
of flowers which are otherw^ise alike and which have no per- 
fume. It is not at all necessary that the colours we term blue, 
purple, red, yellow, etc., should be seen as we see them, or 
even that the sight of them should give them pleasure. 

Again, the use of colour to us is by no means of the same 
nature as it is to insects. It gives us, no doubt, a greater 
facility of differentiating certain objects, but that could have 
been obtained in many other ways — by texture of surface, 
by light and shade, by diversity of form, etc., and in some 
cases by greater acuteness of smell ; and there are very few 
uses of colour to us which seem to be of " survival value ''- — 
that is, in which a greater or less acuteness of the perception 
would make any vital difference to us or would lengthen our 
lives. But if so, the exquisite perception of colour we nor- 
mally possess could not have been developed in our ancestors 
through natural selection ; while what we call the '^ aesthetic 
sense,'' the sense of beauty, of harmony, of indescribable charm, 
which nature's forms and colouring so often gives us is still 
further removed from material uses. Another consideration 
is, that our ancestors, the Mammalia, derived whatever colour- 
sense they possess almost wholly from the attractive colours 
of ripe fruits, hardly at all from the far more brilliant and 
varied colours of flowers, insects, and birds. But the colours 
of wild fruits, which have been almost entirely developed for 
the purpose of attracting birds to devour them and thus to 
disperse their seeds, are usually neither very brilliant nor 
very varied, and are by no means constant indications to us 
of what is edible. It might have been anticipated, therefore, 
that our perception of colour would have been inferior to that 
of birds and mammals generally, not, as is almost certainly 
the case, very much superior, and so bound up Avith some of 



GENERAL ADAPTATIONS 



.» .1 T 



our higher intellectual achievements, tiial \Uv total absence 
of perception of colour would have checked, or pi rliaps wholly 
prevented, all those recent discoveries in spcctrosc^opy which 
now form so powerful a means of acquiring an extended knowl- 
edge of the almost illimitable universe. 

I venture to think, therefore, that we Jiave good reason to 
believe that our colour-perceptions have not been developed in 
us solely by their survival-value in the struggle for existenee ; 
which is all ^ve could have acquired if the views of such think- 
ers as Grant Allen and Professor Ilaeckel represent the wln.b* 
truth on this subject. They seem, on the other hand, to have 
been given us with our higher aesthetic and moral attributes, 
as a part of the needful equipment of a being whose spiritual 
nature is being developed, not merely to satisfy material needs, 
but to fit him for a higher and more enduring life of continued 
progress. 

Colours of Fruits: a Suggestion as to Nuts 

As flow^ers have been developed through insects, so have 
edible fruits been developed and coloured so that birds may 
assist in the dispersal of their seeds ; while inedible fruits have 
acquired endlessly varied hooks or sticky exudations in ord<'r 
that they may attach themselves to the fur of quadrupeds or the 
feathers of birds, and thus obtain extensive dissemination. All 
this was clearly seen and briefly stated by Darwin, and has 
been somewdiat fully developed by myself in the work already 
quoted: but there is one point on which I wish to mai:i* an 
additional suggestion. 

In my Tropical Nature I referred to Grant Allen's view 
(in his Physiological Esthetics) that nuts were '' not intended 
to be eaten"; and in my Darwinism (p. 305) I adopted this 
as being almost self-evident, because, though very largely edible, 
they are always protectively coloured, being green when unrijKi 
and brow^n when they fall u])ou the ground among the decay- 
ino" folia2:e. ^foreover, thoir outer-coverings arc often prickly, 
as in the sweet-chestnut, or bitter as in the walnut, while their 



338 THE WORLD OF LIFE 

seed-boxes are often very hard, as in the hazel-nut, or intensely 
so_, as in the Brazil-nut and many other tropical species. 

But, on further consideration, 1 believe that this apparently 
obvious conclusion is not correct; and that nuts are, as a rule, 
intended to be eaten. I am not aware that this question has 
yet been discussed by botanists, and as it is one of much inter- 
est and exhibits one of the curious and indirect ways in which 
nature works for the preservation of species, both in the vege- 
table and animal world, I will briefly explain my views. 

The first point for our consideration is, that most nuts are 
edible to some animals, and a large number are favourite foods 
even to ourselves. Then they are all produced on large trees 
or shrubs of considerable longevity, and the fruits (nuts, 
acorns, etc.) are produced in enormous quantities. If now 
we consider that in all countries which are undisturbed by 
man, the balance between forest and open country, and be- 
tween one species and another, only changes very slowly as 
the country becomes modified by geographical or cosmical 
causes, we recognise that, as in the case of animals, the number 
of individuals of each species is approximately constant, and 
there is, broadly speaking, no room for another plant of any 
particular kind till a parent plant dies or is destroyed by fire 
or tempest. Imagine then the superfluity of production of 
seed in an oak, a beech, or a chestnut forest; or in the nut- 
groves that form their undergrowth in favourable situations. 
Countless millions of seeds are produced annually, and it is 
only at long intervals of time, when any of the various causes 
above referred to have left a space unoccupied, that a few 
seeds germinate, and the best fitted survives to grow into a 
tree which may replace its predecessor. 

But when every year ten thousand millions of seeds fall 
and cannot produce a tree that comes to maturity, any cause 
which favoured their wider dispersal would be advantageous, 
even though accompanied by very great destruction of seeds, 
and such a cause is found when they serve as food to herbiv- 
orous mammals. For most of these go in herds, such as swine, 



GENERAL AUAriATlOXS 339 

peccaries, deer, cattle, horses, etc., and wlieu .such animals are 
startled while feeding and scamper away, two results, useful 
to the species whose fruit they are feedin-,^ upon, follow. As 
the acorns, chestnuts, etc., usually lie thickly un the ground, 
some will be driven or kicked along wiih the herd; an<l this 
being repeated many times during a season and year after 
year, a number of seeds are scattered Ixyond the limits of the 
j^arent trees. By this process seeds will often reach places 
they would not attain by ordinary means, and may thus be 
effective in extending the range of the species. It would also 
often happen that seeds would be trodden into soft or wet 
ground and thus be actually planted by the devouring animals; 
and being in this case placed out of sight till the herds had 
left the district would have a better chance of cominjr to 
maturity. 

XoAv one such success in a year would more than compensate 
to the species for millions of seeds devoured, and it would 
therefore be beneficial to a species to produce nuts or seeds of 
large size and in great quantities in order to attract numbers 
of mammals to feed on them. This is quite in accordance 
with nature's methods in other cases, as Darwin has shown in 
the case of pollen. The very curious fact of the I5razil-nut 
having such a very hard shell to the triangular seeds and a still 
harder covering to the globular fruit, which falls from the very 
lofty trees without opening, and has to bo broken open with 
an axe by the seed-collectors, is another example. This is saiil 
not to open naturally to let the seed escape for a year or more ; 
and this fact, with its almost perfect globular form, would 
facilitate its being scattered to a considerable distance by the 
feet of tapirs, deer, or peccaries, and when at last the seeds 
fell out, perhaps aided by the teeth or feet of these animals, 
some of them would almost certainly be trodden into the 
ground, and this would be facilitated by their sidvangidar 
shape. If this is the mode of dispersal it has ]u*oved very suc- 
cessful, for the species is widely srattorrd iti moderate-sized 
groves over a considerable portion of th(^ Amazonian forests. 



340 THE WOKLD OF LIFE 

The main facts and probabilities clearly point to the conclu- 
sion that the extensive group of nut-like fruits or seeds are 
intended to be eaten, not by birds while on the trees, but by 
ground -feeding animals — to be devoured wholesale, in order 
to disperse and save a few which may germinate and produce 
another generation of trees. 

The Colours of Plants and Animals in relation to Man 

The views of Ilaeckel and of the whole school of Monists, 
as ^\^e\\ as of most of the followers of Spencer and Darwin, 
are strongly antagonistic to the idea that in the various groups 
of phenomena w^e have so far touched upon there has been in 
any real sense a preparation of the earth for man; and those 
who advocate such a theory are usually treated with scorn as 
being unscientiiic, or Avith contempt as being priest-ridden. 
Darwin himself was quite distressed at my rejection of his 
own conclusion — that even man's highest qualities and pow- 
ers had been developed out of those of the lower animals by 
natural or sexual selection. Several critics accused me of 
^' appealing to first causes " in order to get over difficulties ; 
of maintainins: that '^ our brains are made bv God and our 
lungs by natural selection " ; and that, in point of fact, " man 
is God's domestic animal." This was when I published my 
Contributions to the Theory of Xatural Selection, in IS 70, its 
last chapter on The Limits of ^Natural Selection as applied to 
Man, being the special object of animadversion, because I 
pointed out that some of man's physical characters and many 
of his mental and moral faculties could not have been pro- 
duced and developed to their actual perfection by the law of 
natural selection alone, because they are not of survival value 
in the struggle for existence. 

In the present work I recur to the subject after forty years 
of further reflection, and I now uphold the doctrine that not 
man alone, but the whole World of Life, in almost all its varied 
manifestations, leads us to the same conclusion — that to afford 
any rational explanation of its phenomena, w^e require to pos- 



GENERAL ADAPT AT lOXS 341 

tulate the continuous action and guidance of higher intelli- 
gences; and further, that these have prul)ahly been working 
towards a single end, the development of intellectual, moral, 
and spiritual beings. I will now indicate briefly how the facts 
adduced in the present and preceding chapters tend to support 
this view. 

Having shown in the last chapter that the phenomena of 
groiuth in the animal world, and especially as manifested in 
the feathers of birds and the transformation> of the higlier 
insects, are absolutely unintelligible and unthinkable in the 
absence of such intelligence, we must go a stc}) further and 
assume, as in the highest degree proliable, a pur|)o>c which 
this ever-present, directing, and organising intelligence has had 
always in view. We cannot help seeing that we ourselves are 
the highest outcome of the developmental process on the earth ; 
that at the time of our first ajopearance, plants and animals 
in many diverging lines had approached their highest develop- 
ment; that all or almost all of these have furnished species 
"which seem peculiarly adapted to our purposes, whether as 
food, as providing materials for our clothing and our varied 
arts, as our humble servants and friends, or as gratifying our 
highest faculties by their beauty of form and colour : and as 
our occupation of the earth has already led to the extinction 
of many species, and seems likely ultimately to destroy many 
more except so far as we make special efforts to preserve them, 
we must, I think, assume that all these consequences of our 
development were foreseen, and that results which srrm to bo 
so carefully adapted to our wants during our growing civilisa- 
tion were really prepared for us. If this be so, it follows that 
the much-despised anthropomorphic view of the whole develop- 
ment of the earth and of organic nature was, after all, tho 
true one. 

But if the view now advocated is not so wholly unscientific, 
so utterly contemptible as it has hitherto been declared to bo 
by many of our great nuthnrities, it is certainly advisable to 
show how various facts in nature bear upon it and are ex- 



342 .THE WOKLD OF LIFE 

plained by it. I will therefore now add a few more consid- 
erations to those I have hitherto set forth. 

On the question of the colour-sense I have already argued 
that though it may exist in birds and insects, it is hardly likely 
that it produces any such high aesthetic pleasure as it does in 
our own case. All that the evidence shows is, that thev do 
perceive what are to us broad differences of colour, but we have 
no means whatever of knowing n:]iai they really perceive. It 
is a suggestive fact that colour-blind persons, though they do 
not see red and green as strongly contrasted as do those with 
normal vision, yet do perceive a difference between them. It 
is therefore quite possible that birds may see differences be- 
tween one strongly marked colour and another without any 
sense of what we should term colour, and at all events without 
seeing '' colours " exactly as we see them. It is now generally 
admitted that birds arose out of primitive reptiles, and from 
their very origin have been quite distinct from mammals, 
which latter probably diverged a little later from a different 
stock and in a somewhat different direction. The eyes of both 
were developed from the already existing reptilian eye, and 
their type of binocular vision may be very similar. But at 
that early period there were, it is believed, no coloured flowers 
or edible coloured fruits, and it is probable that the perception 
of colour arose at a much later period. It is therefore unlikely 
that a faculty separately developed in two such fundamentally 
different groups of organisms should be identical in degree or 
even in nature unless its use and purpose were identical. But 
birds are much more extensive fruit-eaters than are mammals, 
the latter, as we have seen, being feeders on nuts which are 
protectively tinted rather than on fruits, while their largely 
developed sense of smell would render very accurate perception 
of colour needless. It is suggestive that the orang-utan of 
Borneo feeds on the large, green spiny Darian fruit ; and I 
have also seen them feeding on a green fruit which was re- 
pulsively bitter to myself. Our nearest relatives among exist- 
ing quadrupeds do not therefore seem to have any need of 



GExXEEAL ADAPTATiUAS 343 

a refined colour-sense. AVliy then should ii have been so highly 
developed in us? It was one of the finKhmir^ntnl maxims of 
Darwin that natural selection couhl not prudiK-u absolute, but 
only relative perfection; and airain, that no species could 
acquire any faculty beyond its needs. 

The same ar^iments will apply even more strongly in the 
case of insects. They appear to recognise the colour-, the 
formSj and the scents of flowers, but we can only vagufly guess 
at the nature and quality of their actual sensations. Their 
whole line of descent is so very far removed from that of the 
birds that it is in the highest degree iinpnjbable that there is 
any identity even in their lower mental faculties with those 
of birds. For the colour-sense is mental, not })hysical ; it 
depends partly on the organ of vision, but more fundamentally 
on the nature of the nervous tissues which transform the etlects 
of light-vibrations into the visual impressions which irc rec- 
ognise as colour, and ultimately on some purely mental faculty. 
But the colour-sense in insects may be quite other than the 
bird's or than our own, and mav in most cases be combined 
with scent, and often with form to produce the recognition 
of certain objects, which is all they require. 

Yet insects, birds, and the flowers and fruits which attract 
them, all exhibit to our vision nearlv the same ranjje of the 
colour-scheme, and a verv similar intensitv, brilliancv, and 
purity of colour in particular cases; which is highly remark- 
able if their respective needs were the only etiicient causes in 
the production of these colours. Looking first at flow( rs, how 
very common and conspicuous are those of a yelh»w colour, 
yet far beyond the average are the rich orange petals of tlie 
Escholtzia and the glistening splendour of st^me of our butter- 
cups; red and purples are innumerable, yet in the Lobelia 
fulqens and some other flowers we r(\'ieh an intensity of huo 
which seem to us un^urpassahly b(\iutiful; blues of the type 
of the campanulas or the v.'irious blue lillaceir are all in tlieir 
way charming, but in the blue salvia (Salvia patens) the 
spring gentian {Geniiana vcrna), and a few others, we perceive 



U4: THE WOJRLD OF LIFE 

a depth and a purity of liue which seem to have reached the 
limits of the possible. We may surely ask ourselves whether 
these exquisite refinements of mere colour as well as the in- 
finity of graceful forms, and the indescribable delicacies of 
texture and of grouping, are all strictly utilitarian in regard 
to insect-visitors and to ourselves. To them the one thing 
needful seems to be a sufficient amount of difference of any 
kind to enable them to distinguish among species which grow 
in the same localitv and flower at the same time. 

Special Cases of Bird-colouration 

Coming now to birds, we find the colours with which they 
are decorated to be fully equal in variety and purity of tint 
to those of flowers, but extending still further in modifications 
of texture, and in occasionally rivalling minerals or gems in 
the brilliancy of their metallic lustre. The exquisite blues 
and vinous purples, reds and yellows of the chatterers and 
manakins, the glorious metallic sheen of the trogons, of many 
of the humming-birds, and of the long-tailed paradise-bird ; 
the glistening cinnabar-red of the king-bird of paradise, ap- 
pearing as if formed of spun-glass ; the silky orange of the 
cock-of-the-rock and the exquisite green of the Malayan crested 
gaper, are only a few^ out of thousands of the extreme refine- 
ments of colour with which birds are adorned. 

Add to these the marvellous ornaments with which the males 
are so frequently decorated, the crests varying from the feath- 
ery dome of the umbrella bird, to the large richly coloured 
crest of the roval flvcatcher of Brazil, and the marvellous blue 
plumes from the head of the fern-bearing bird of paradise 
(Pteridopliora Alherti), with a thousand others hardly in- 
ferior, and we shall more than ever feel the want of some 
general and fundamental cause of so much beauty. 

All this w'ealth of colour, delicacy of texture and exuber- 
ance of ornament, has been explained hitherto as being utili- 
tarian in two ways only: (1) that they are recognition-marks 
of use to each species, more especially during its differentiation 



GEXEKAL ADAI^TATIONS 345 

as a species; and (2) as inllucncing female choice of the must 
ornamental males, and tlicrclure of use to each species in the 
struggle for existence. The former I have, I tliink, proved to 
be a true cause; the latter I reject for reasons given ii» my 
Darwinism. I there give an alternative solution of the prol>- 
lem which I still think to be fundnmontally correct and whicli 
has been arrived at by Weismann and others from theoretical 
considerations to whicli 1 may advert hiter on. 

C olouration of Insects 

Passing now to tlie order of insects wliich perhaps pxhil»its 
the greatest range of colour-display in the wh(de of the organic 
world — especially in the order Lepido])tera, we find the dif- 
ficulties in the way of a purely utilitarian solution still greater. 
Any one who is ac(iuainted with this order of insects in its 
fullest development in the equatorial zone of the great conti- 
nents, will recognise liow impossible it is to give any ade<piato 
conception of its wealth of colour-decoration by a mere verbal 
description, "^'et the attempt must be made in order to com- 
plete the argument 1 am founding upon a consideration of the 
whole of the facts of orc^anic colouration. 

Even in the temperate zones we have a rich display of colour 
and marking in our exquisite little blues, our silver-spotted 
fritillaries, our red-admiral, our peacock, and our orange-tip 
butterflies, and on the Continent, the two swallow-tails, the 
apollo butterflies, the fine Chaaxcs Jason, and many other*. 
But these are absolutely as nothing compared to the wealth 
of colour displayed in the eastern and western tropics, where 
the average size is from two to three times ours, and the num- 
bers, both in species and individuals at least ten times as great. 
Not only is there every tint of red, yellow, Mue and gretMi, 
on ground-colours of black or white an<l various slunles of 
brown or buff, but we find the most vivid metallic hlues or 
silky yellows covering a largi' j)orti<»ii of tlie wing-surface or 
displayed in n variety of patteni< ihat i- almost bewildering 
in its varietv and beauty. 



346 THE WOELD OE LIFE 

As a few examples, the Callitliea sapphira of the Amazon 
is of a soft, celestial blue that the finest lobelia or gentian 
cannot surpass. The grand Oenithoptera Amphrisius, and its 
allies has the hind wings of an intense yellow with a silky 
lustre, while 0. Prianius and many allied species are richly 
adored with metallic green, deep orange, or violet-blue. 
Papilio Ulysses of Amboyna equals in size and colour the 
splendid blue morphos of South America ; while these latter 
not only present us with every shade of blue on insects of 
the largest size, but in Morpho cypris, and several allied 
species exhibit an intensity of colour and of metallic sheen 
that is equal to the highest efforts of nature in this direction 
on the caps or the gorgets of humming-birds, on the glittering 
shields of the Epimachidse of ^N^ew Guinea, or on such precious 
gems as the emerald, the sapphire, the ruby, or the opal. 

The exquisite combinations of brilliant colour and endless 
variety of pattern to be found among the small Lycsenidae 
and Erycinidse of both hemispheres must be passed over; as 
well as the somewhat larger Catagrammas whose diversified 
upper and under sides are a constant delight; while the vast 
groups of the Heliconidse and Danaidse, inedible to most birds 
and lizards, are often rendered conspicuous by bold contrasts 
of the purest white, yellow, or red, on a blue-black ground. 

Some Extremes of Insect-Coloration 

There are some examples of tropical butterflies in which 
nature may be said to have surpassed herself, and to have 
added a final touch to all the beauty of colour so lavishly dis- 
played elsewhere. These are to be found in a few species 
only in both hemispheres, and are therefore the more remark- 
able. The largest butterfly to exhibit this form of colour is 
the Ornithoptera magellanus, from the Philippines, whose 
golden-yellow wings, when viewed obliquely acquire the chang- 
ing hues of polished opals, quite distinct from any of its 
numerous allies which possess the same colour but with what 
may be termed a silky gloss. In the same part of the world 



GEXEEAL ADAriATlOXS 347 

(the Bismarck Archipelago) there is a day-flyinn; i,„,th 
(Burgena chalyhcata), one of the A<:aristifhi', wIkjso wings 
change from Mack to blue and a fiery opalcsci-nt red. In 
tropical America there is a group (»f hutterilies of tlic g«-nii8 
Papilio, which are very abuii(hiiit botli in species and in«livid- 
uals, whose velvet-black wings liav(^ a few bands or -jiois uf 
blue or green on the upper pair, while the lower have a ban<l 
of spots near the posterior margin of a brilliant cTimsnn. 
Among perhaps a hundred species with this general style oi 
coloration, there are a few (perhaps a dozen) in which ihe 
red of the hind wings, when viewed very obli(iu('ly fn^ni be- 
hind, changes into opalescent and then into a curious bluish 
phosphorescence of intense brilliancy. 

I am informed by Dr. K. Jordan (of the Tring Zoohtgical 
Museum) that in these insects the black ground of the wing 
changes also into metallic blue, which seems to spread over 
the red and to aid in the production of the phosphorescent 
effect. This is so marked that ^Ir. Bates gave to one of the 
new species he described, the name of Papilu) phosplionis. 
One of the small Er^'cinidae (Euseldsia prcvclara) found in 
the Upper Amazon valley, is of a yellow butf colour, with a 
wonderful opalescent reflection which is said to be tlic most 
intense and brilliant in the whole order of Lepidoptera iuid 
probably the most brilliant colour known. 

All metallic reflections in the animal world are what aro 
called interference-colours, and are prttduced by excessively 
fine lines or rugosities on polishe<l surfaces, or by ('<iually 
thin transparent lamina^. It is probable that in the remark- 
able changing glows now described, l)olh these eauses may 
come into play, producing, wlion viewed at eertain auirles, 
an intensity of hue resembling those of the linest opals, or 
sometimes imitating the most brilliant glow-worms or fire- 
flies bv means of reflecteil light. It se(Mn< |»rol)able that tliCi^e 
rare hues mav be nt' a pi-oleetivc nature, siui-e a pur-ning bird 
miiilit be start le(l hv tli*' sudden fla-hinrr out of -n l)rilliant a 
light and thus allow the inject to escape: lnu that dor'< not 



348 THE WOKLD OF LIFE 

render it more probable that the infinitely complex arrange- 
ments by which such structures are produced and transmitted 
unfailingly to offspring, should have been brought about for 
this purpose alone, when thousands of other species arrive 
at the same end by far simpler means. 

E"ow if there was a difficulty in the view that all the wealth 
of colour and beauty in birds has been developed solely on 
account of its utility to themselves, that difficulty becomes 
greatly increased in the case of these insects. The described 
butterflies alone are already far more numerous than birds, 
and there are certainly more to be discovered of the former 
than of the latter. Bates well observed that the expanded 
wings of butterflies seemed to have been used by nature to 
write thereon the story of the origin of species. To this we 
may, I think, add that she has also used them, like the pages 
of some old illuminated missal, to exhibit all her powers in 
the production, on a miniature scale, of the utmost possibili- 
ties of colour-decoration, of colour-variety, and of colour- 
beauty ; and has done this by a method which appears to us 
unnecessarily complex and supremely difficult, in order per- 
haps to lead us to recognise some guiding power, some supreme 
mind, directing and organising the blind forces of nature in 
the production of this marvellous development of life and 
loveliness. 

It must always be remembered that what is produced on 
the flow^er, the insect, or the bird, is not colour, but a surface 
so constituted in its chemical nature or mechanical texture 
as to reflect light of certain w^ave-lengths while absorbing or 
neutralising all others. Colour is the effect produced on our 
consciousness by light of these special wave-lengths. To claim 
that the lower animals, especially the mammals, perceive all 
the shades and intensities, the contrasts and the harmonies of 
colours as we perceive them, and that they are affected as we 
are with their unequalled beauty is a wholly unjustified 
hypothesis. The evidence that such sensations of colour exist 
in their case is wholly wanting. All wc really know is, that 



GENERA!. Al )ArTA TK ).\S :]|;) 

they appear to percoivo (lifTcrciicfs wlicn- wc j.. re. nc cnlour, 
but it has not hoen ))!•(. vcd liow far tlii- iMi-ccption cxtfinU, 
since in the most intollii^^cnl «»f tlu'sc, (|(i«:> and horses, the 
sense of smell is so highly developed as for many purposes to 
take the place of vision. 

It is a very suggestive fact that tho tlioory of tlie develop- 
ment of the colour-sense through its utility, receives least s\ij>- 
port from those animals Avhich are nearest to us, and from 
which we have been corporeally developed — the niannnals; 
rather more support from those which have had a \vi(hdy dif- 
ferent origin — the birds ; and apparently most from tlioso 
farthest removed from us — the insects, for whom it has been 
claimed that we owe them all the floral beauty of the vege- 
table kingdom, through their refined perception of ditTerences 
of form and colour. This seems to me to be a kind of 
redudio ad dbsurdum, and to constitute a disproof of that 
whole argument as a final cause of the colour-sense. On the 
other hand, it gives the strongest support to the view that the 
refined perception and enjo\inent of colour ive possess has 
not, and could not have been developed in us by its survival- 
value in our early struggle for existence, but that these faculties 
are, as Huxley remarked in reirard to his eniovment of scenerv 
and of music, ^^ gratuitous gifts,'' and as such are powerful 
arsninients for ^' a benevolent Author of the Universe/' * 

iSee Darwinism (3rd ed. 1901), p. 478, Appendix. 



CHAPTEE XVI 

THE VEGETABLE KINGDOM IN ITS SPECIAL EELATION 

TO MAN 

It is obvious that, as animal life has from its very origin 
depended upon and been developed in relation to plant life, 
the entire organisation of the former would, by the continuous 
action of variation and survival of the fittest, become so 
harmoniously adapted to the latter, that it would inevitably 
have every appearance of the plant having been formed and 
preordained for the express purpose of sustaining and benefit- 
ing the animal. This harmonious co-adaptation cannot there- 
fore be adduced as, of itself, being any proof of design, but 
neither is it any proof against it. So with man himself, so 
far as his mere animal wants are concerned, his dependence 
on plants, either directly or indirectly, for his entire sus- 
tenance by food, and therefore for his very life, affords no 
grounds for supposing that either of the two kingdoms came 
into existence in order to render the earth a possible dwelling- 
place for him. But as regards those special qualities in which 
he rises so far above all other animals, and especially those 
on which the higher races found their claim to be " civilised," 
there seem to be ample grounds for such an argument, as I 
hope to be able to show. 

Taking first the innumerable different kinds of wood, whose 
qualities of strength, lightness, ease of cutting and planing, 
smoothness of surface, beauty, and durability, are so exactly 
suited to the needs of civilised man that it is almost doubtful 
if he could have reached civilisation without them. The con- 
siderable range in their hardness, in their durabilitv when ex- 
posed to the action of water or of the soil, in their weight 
and in their elasticity, render them serviceable to him in a 

350 



PLANTS IN RELATIOX TO MAX nr>i 

thousand ways which arc totally removed from any use made 
of them by the lower animals. 

Few of these qualities seem essential to themsclvos as vege- 
table growths. They might have been much smaller, which 
would have greatly reduced their uses; or so much harder as 
to be almost unworkable; or so liable to fracture as to ho 
dangerous; or subject to rapid decay by the action of air, or 
of water, or of sunshine, so as to be suitable for temjuirarv 
purposes only. With any of these defects they miirht have 
served the purposes of the animal world (piite as well as they 
do now; and their actual properties, all varyinir alxuit a mean 
value, which serves the infinitely varied purposes to which we 
daily and hourly apply them, may certainly be adducc<l as an 
indication that they were endowed with such properties in 
view of the coming race wdiich could alone utilise them, and 
to whose needs they minister in such an infinite variety of 
ways. 

As one example of what such a different quality of tind)er 
as above indicated might mean let us remember that from bo- 
fore the dawn of history down to about the middle of the last 
century every ship in the world was built of wood. lla<l no 
wood existed suitable for sea-going vessels, the whole course of 
history, and perhaps of civilisation, would have been dilTerent. 
Without ships the Mediterranean would have been almost as 
impassable as was the Atlantic. America would be still un- 
known, as well as Australia and possibly S..iitli Africa; and 
the whole world would be for us smaller than in ilie days be- 
fore Columbus. And all this might have happened had tlie 
nature of vegetable growth, while dift'ering little in external 
form and equally well adapted for unintelligent animal life, 
not possessed those special qtuditics which fitted it for minis- 
tering to the varied needs of intellectual, inventive, and ever 
advancing man. 

But, even with the whole vegetable world in \\< (Uitwanl 
aspect and mechanical properties exactly as it is now, there 
are still a thousand wavs in which it ministers to tlie needs 



352 THE WOKLD OF LIFE 

of our ever-growing civilisation, whicli have little or no re- 
lation to the animal world Avhich grew up in dependence on 
it. Leaving out of consideration the vast number of fruits, 
and cereals, and vegetables which supply him with varieties 
of food, which may be of more importance to man in the 
future than thev are now, let us take first the innumerable 
drugs which enable him to avoid some of the evils brought 
upon himself by his ignorance, his dissipations, or his wilful 
neglect. The pharmacopeias of every country and every age 
are crowded with the names of herbs and simples used with 
more or less success as remedies for the various diseases man 
was supposed to be heir to, and if many of these were alto- 
gether imaginary, very large numbers still hold their place as 
of real and often of inestimable value. To name onlv a few 
of the best known, we could hardly dispense with such 
common drugs as aloes, arnica, belladonna, calendula, cascara, 
gentian, jalap, ipecacuanha, nux vomica, opium, podopholin, 
quinine, rhubarb, sarsaparilla, and a host of others. 

To these we mav add the various '' balsams " so much used 
in ancient surgery — balm of Gilead, friar's balsam, balsam 
of Peru, benzoin, camphor, etc. 

Then there are the ordinary resins and gums so useful in 
the arts — copal, dammar, mastic, kauri, gum-arabic, traga- 
canth, asafoedita, gamboge, etc. 

Among the numerous dyes are amatto. Brazil-wood, log- 
wood, camwood, fustic, indigo, madder, turmeric, and woad. 

Vegetable oils, used for cooking, lighting, perfumes, 
medicines, etc., are very numerous. Such are candle-nut, 
castor oil, coco-nut oil, colza oil, olive oil, cotton seed, 
linseed, and rape-seed oils, cajeput oil, and innumerable others 
in every part of the world, known or yet to be discovered. 

Perfumes and spices are also extremely abundant, such as 
caraways, cinnamon, cloves, mace, nutmegs, patchouli, pepper- 
mint, orris-root, sandal wood, sassafras, tonquinbeans, vanilla, 
and the many essential oils from highly perfumed fruits and 
flowers. 



PLAXTS l.\ 1 ii: LAT I ().\ To MAX nnn 



•JJO 



Of foods and drinks not used l).v ihc lower animals, are 
arrowroot, tapioca, sa^^), sugar, wine, l.cer, i.-a, eolTee, :ind 
cocoa, the last six, wlicn nscd in moderation, Indn-,^ among 
the choicest gifts of nature. 

There remain a number of vegetaMc pn.diict-^ inv;duahle 
for arts and manufaelures — cotton and tlax for (doihing, 
hemp for cordage, rattan and bandjoo for tropical furniture, 
boxwood for wood-engraving, gutta-percha for machine belts 
and a great variety of economic uses, and lastly india-rubU.-r, 
one of the greatest essentials of our chemieal and mechanical 
arts, without which neither the electric telegraph, the bicycle, 
nor the motor-car could have reached their present stage of 
perfection, while no doubt many equally important uses re- 
main to be discovered. 

It may be objected that so many of these varied products 
have been shown to be of use to the plants themselves as 
protections against injurious insects or from being devoured 
in their young state by herbivorous mammals, that their utility 
to man is only an accidental result, and of no real signiticancc. 
But this objection can hardly be a valid one when we consider 
the enormous number of beneficial drugs, highly agreeable 
scents and spices, useful oils, and delicious foods or drinks, 
that are among the commonest of vegetable bye-products. 
There seems no direct connection between juices or volatile oils 
which are distasteful to insects, and drugs which are valuable 
medicines in the case of human diseases. The leaves or stems 
of seedling plants needed only a temporary protection, while 
the juices which effect it not only increase in (piantity dur- 
ing the whole life of the plant, but are transfornuil into such 
as are of unmistakeable value to civilised man. It is almost 
inconceivable that the exquisite fragrance tleveloped only by 
roasting the seed of the coifee shnd) should be a chance result 
of the nature of the juices essential for the well-being of this 
particular species; or that the strange mechanical properties 
of india-rubber should be developed in a few otdy of the thou- 
sands of species having a ])rotective milky sap. 



35i THE WOELD OF LIFE 

Before leaving this brancli of my subject, 1 must say a few 
words on the indications afforded by these varied products 
of plant-life, of the absolute necessity of a directive power 
and a mind of the highest organising intelligence for their 
production. Quite as clearly, perhaps even more clearly than 
for the development of the bird's feather or the insect's trans- 
formations, does the agency of such a supreme mind seem to 
be essential. 

Let us consider first the extreme simplicity and uniformity 
of the conditions under which such marvellously diverse re- 
sults are produced. A very large proportion of the vegetable 
products useful to man are obtained from the tropical forests, 
where the temperature is more uniform, the moisture more 
constant, and the trees less exposed to wind than anywhere 
else in the world. The whole organisation of the higher 
plants is, as compared with that of animals, extremely simple, 
and they are wonderfully similar in structure to each other, 
even in distinct genera and natural orders. The roots, the 
wood, the bark, the leaves, are substantially of the same type 
in thousands of species. All alike build up their structures 
out of the same elements, which they obtain from the water 
and the few substances it dissolves out of the soil, from the 
air and the carbonic acid and aqueous vapour it contains. 
Yet under these conditions w^hat a seemingly impossible 
variety of products arise. 

When the modern chemist attempts to bring about the same 
results as are effected by nature in the plant, he has to em- 
ploy all the resources of his art. He has to apply great heat 
or great cold ; he uses gas or electric fires and crucibles ; he 
requires retorts for distillation, and air-tight vessels and tubes 
for the action of his reagents, or to preserve his liquid or 
gaseous products ; but with all his work, carried out for more 
than a century by thousands of earnest students, he has only 
been able to reproduce in his laboratory a limited number of 
organic substances, while the more important of the constit- 



PLAXTS IX IIEJ.ATIOX To MAX 35 



oo 



UGiits of liviug- urgaiii.Niiis i-cuiaiii I'ar Im'^uikI his pijwcrs of 
yynthesis. 

The conditions under wldcli rial hit works in ilic vpffotablc 
kingdom are the very (jpposite of all this. Starting fr«>ni 
the ripened seed, consisting essentially of a single fertilised 
cell and a surrounding mass of nutritive material, a root is 
sent out into the soil and a shoot into the atmosphere, from 
which the whole plant with all its tissues and vessels arc 
formed, enabling it to rise up into the air so as to obtain 
exposure to light, to lift up tons weight of material in the 
form of limbs, branches, and foliage of forest trees, often to 
a hundred feet or more above the surface, by means of forces 
whose exact mode of operation is still a mysten.^ ; while by 
means of the very same tissues and vessels those recondite 
chemical processes are being carried on which result in the 
infinitely varied products already very brietly referred to. 

The living plant not only builds up its own man-ellous 
structure out of a few elements supplied to it either in a 
gaseous or liquid state, but it also manufactures all the aj> 
pliances — cells, vessels, fibres, etc. — needful for its complex 
laboratory work in producing the innumerable l)V(v})roducts 
possessing so many diverse properties useful to man, but which 
were mostly unneeded by the remainder of the animal world. 

Usually botanists as well as zoologists are satisfied to de- 
scribe the minute structure of the organs of j)lants or animals, 
and to trace out as far as possible the changes that occur dur- 
ing growth, without any reference to the unknown and un- 
intelligible forces at work. As Weismann has state<l, the 
fundamental question — ''the causes and mechanism by which 
it comes about that they (the germicides or physinlogical 
units) are always in the right place and develoj) into colls 
at the right time" — is rarely or never touched uptju.' 
Modern theories of heredity take for granted the essential 
phenomena of life — nutrition, assiniilati(ui, antl growth. 

1 Tlie Germ riasiii, p. 4. 



356 THE WORLD OY LIFE 

I find, however, that Professor Anton Kemer, in his great 
■work on The Natural History of Plants, fully recognises this 
great fundamental problem, and even recurs to the much 
derided " vital force '' as the only help to a solution of it. 
He says: 

" The phenomena observed in living protoplasm, as it grows and 
takes definite form, cannot in their entirety be explained by the 
assumption of a specific constitution of protoplasm for every dis- 
tinct kind of plant, though this hypothesis may prove useful when 
we enquire into the origin of new species." 

Again he says: 

" In former times a special force was adduced, the force of life. 
More recently, when many phenomena of plant-life had been suc- 
cessfully reduced to simple chemical and mechanical processes, this 
vital force was derided and effaced from the list of natural 
agencies. But by what name shall we now designate that force in 
nature which is liable to perish whilst the protoplasm suffers no 
physical alteration and in the absence of any extrinsic cause; and 
which yet, so long as it is not extinct, causes the protoplasm to move, 
to enclose itself, to assimilate certain kinds of fresh matter coming 
within the sphere of its activity and to reject others, and which 
when in full action makes the protoplasm adapt its movements un- 
der external stimulation to existing conditions in the manner which 
is most expedient? 

" This force in nature is not electricity nor magnetism ; it is not 
identical with any other natural force; for it manifests a series of 
characteristic effects which differ from all other forms of energ}\ 
Therefore, I do not hesitate again to designate as ' vital force ' this 
natural agency, not to be identified with any other, whose immedi- 
ate instrument is the protoplasm, and whose peculiar effects we call 
life. The atoms and molecules of protoplasm only fulfil the func- 
tions which constitute life so long as they are swayed by this vital 
force. If its dominion ceases they yield to the operation of other 
forces. The recognition of a special natural force of this kind is 
not inconsistent with the fact that living bodies may at the same 
time be subject to other natural forces" (p. 52). 



PLA^s'TS l.\ KEL.VTiO.\ it) .MAX 357 

And again, after discussing the various effects pro<luce(l by 
that wonderful substance chlorophyll, he says: 

" We see the effective apparatus, we niugnisu the f(x)(l-ga.scg 
and food-salts collected for working up, wo know that tlie nun's 
rays act as the motive force, and we also identify the prodiu-t^ 
which appear completed in the chloropliyil granules. By careful 
comparison of various cells containing chlorophyll, having found 
by experience that under certain external conditions the wliole ap- 
paratus becomes disintegrated and destroyed, it is indeed permiftrti- 
ble to hazard a conclusion about the propelling forces. But what 
is altogether puzzling is, how the active forces work, how the sun\s 
rays are able to bring it about that the atoms of the raw mat<.'rial 
abandon their previous grouping, become displaced, intermix one 
with another, and shortly reappear in stable combinations under a 
wholly different arrangement. It is the more difficult to gain a 
clear idea of these processes, because it is not a question of thai dis- 
placement of the atoms called decomposition, but of tliat process 
which is known as combination or synUicsis'' (p. 377). 

I have made these quotations from one of the greatest Ger- 
man \vriters on botany^ in order to show that a professor of 
the science, with a most extensive knowledge of every aspect 
of plant-life, supports the conclusion I had already reached 
from a consideration of some of the broader phenomena of 
animal life and organisation. In the last paragraph (pioted 
he even shows that phenomena occur during the growth of 
the plant, which are, as I suggested from other facts, a»ni- 
parable in complexity with those of the metamoqihosis of the 
higher insects, and, therefore, equally requiring the agenc}* 
of some high directive power for an adequate rati(uuil (explana- 
tion of them. 

I am quite aware that this view, of the earth and organic 
nature having been designed for the development of the Innnan 
race, and further, that it has been so dc-iirned that in the 
course of its entire cvolutlnn, ii-; detailed I'eatures and organi- 
sation have been such as not only to serve the purposes of the 



358 THE WORLD OF LIFE 

whole series of living things, but also in their final outcome, 
to serve the purposes and add to the enjoyments of man, is 
highly distasteful to a large proportion of scientific workers. 
They think, and some of them say, that it is a return to the 
old superstition of special creation, that science has nothing 
to do with first causes, whether in the form of spiritual or 
divine agencies, and that once we begin to call in the aid of 
such non-natural and altogether hypothetical powers we may 
as well give up science altogether. In my early life I should 
have adopted these same arguments as entirely valid, and 
should perhaps have thought of the advocates of my present 
views with the same contemptuous pity which they now be- 
stow upon myself. But, I venture to urge, the cases are not 
fairly comparable, because both their point of view and my 
own are very different from those of our fellow-workers of the 
first half of the nineteenth century. 

Let me recall the conditions that prevailed then as compared 
with those of to-day. Then the opposition was between science 
and religion, or, perhaps more correctly, between the enthusias- 
tic students of the facts and theories of physical science in the 
full tide of its efforts to penetrate the inmost secrets of nature, 
and the more or less ignorant adherents of dogmatic theology. 
]N^ow, the case is wholly different. Speaking for myself I 
claim to be as whole-heartedly devoted to modern science as 
any of my critics. I am as fully imbued with the teachings 
of evolution as they can be ; and I still uphold, as I have al- 
ways done, the essential teachings of Darwinism. 

Darwin always admitted, and even urged, that " Xatural 
Selection has been the most important but not the exclusive 
means of modification." He always adduced the " laws of 
Growth with Reproduction," and of " Inheritance with Varia- 
bility," as being fundamental facts of nature, without which 
Natural Selection would be powerless or even non-existent, 
and which, then as now, were and are wholly beyond explana- 
tion or even comprehension. He elaborated his theory of 
Panagenesis for the purpose of rendering the many strange 



PLAA'TS IX UELATIOX To .MAX 30t) 

facts of inheritance mure nninti'lligil)lc, l)ut cvon if it were 
IJroved to be an exact representation of the facts it would not 
be an explanation, because, as Weismann, Kcrncr and 
many others admit, it wuiild n(jt account fur ilic forces, 
the directive agency, and the orijunisiixf jx^wer wliich arc es- 
sential features of growth. This is felt so strongly bv all tiie 
great workers in pliysiology, that even Ilaeckel has Ix-en driven 
to postulate " mind, soul, or volition," not only in every cell 
but in each organic molecule or physiological on it. And then, 
to save himself from the slur of being ^^ unscieniilic," an«l of 
introducing the very organising power he had <l(ridcd when 
suggested by others, he loudly proclaims that hi- *' soul- 
atom," though it has " Avill " is yet wholly " nnc<mscious." ' 

I again urge, therefore, that our greatest anthorities admit 
the necessity of some mind — some organising and directive 
power — in nature; but they seem to contemplate merely some 
unknown forces or some innate rudimentarv mind in cell or 
atom. Such vague and petty suppositions, however, do not 
meet the necessities of the problem. I admit that sueh forces 
and such rudimentary mind-power may an<l imtbably do ex- 
ist, but I maintain that they are wholly ina(h'(juate, and that 
some vast intelligence, some pervading spirit i-; re(jnire<l to 
guide these lower forces in accordance with a pre-ordained 
system of evolution of the organic world. 

If, how^ever, we go as far as this, we must go farther. If 
there is a ruling and creative power to which the existence 
of our cosmos is due, and if we are its one and unitpie high- 
est outcome, able to understand and to make use of the forces 
and products of nature in a way that no other animal lias been 
able to do; and if, further, there is any reasonable probability 
of a continuous life for us to still further develop that higher 
spiritual nature which we possess, tlu^n W(^ have a ])erfect 
right, on logical and scientific grounds, to see in all the inti- 
nitely varied products of tli(> animal nn.l vegetable kingdoms, 

1 The Riddle of the L'niverse. p. 04. 



3 CO THE WOKLD OF LIFE 

Avhich we alone can and do make use of, a preparation for 
ourselves, to assist in our mental development, and to fit us 
for a progressively higher state of existence as spiritual be- 
ings. 



CIlAl^TKK XV 11 

THE MYSTERY OF THE CVAA. 

I HAVE already given a short aecount of the chemical composi- 
tion of protoplasm — the hii!;hly complex snhstance now ln-M 
to be the physical basis of life, and by one scIkjoI of biulorrists 
alleged to explain, as a resnlt of that complexity, all the won- 
drous phenomena of growth and development. 1 now propose 
to give a very brief sketch of the physical characteristics of the 
living cell, of its internal structure, and of the extraordinary 
internal changes it undergoes during the growth or reproduc- 
tion of all organisms. 

One of the lowest or most rudimentary forms of life is 
the Amoeba, a living cell, just visible to the unaided eye as 
a little speck of floating jelly. This creature, being one of 
the most common of living microscopic objects, will have been 
seen by most of my readers. At first, under a low microscopic 
power, it appears structureless, as it was for some time de- 
scribed to be, but with increasing power and perfection of the 
microscope it is found to consist of three parts — a central 
body of a nearly globular shape slightly darker and more 
granular in texture, the outer jelly-like mass, and a small more 
transparent globular portion, which looks like an air-bubble, 
and is seen to undergo a slow motion of contraction and ex- 
pansion; this is termed the "contractile vacuole,'' which, 
when it has reached its full size, p(Thaps a quarter «»r a fifth 
of the whole diameter, suddenly disappears, and after a little 
while reappears and gradually grows again to it< maximum 
size. The shape of the Amceba varies greatly. Sometimes it 
is globular and immovable, but most fr':^quently it is very ir- 
regTilar with arm-like processes jutting out in various direc- 
tions. By careful watching, these are seen t-. increase or 

[]G1 



362 THE WORLD OF LIFE 

diminish so as to change the whole shape in an hour ov two. 
But more curious is its power of absorbing any particles of 
organic matter that come in contact with it by gradually en- 
closing them in its substance, wdiere after a time they dis- 
appear. The Amoebae are found in stagnant water full of or- 
ganic matter, and if they are transferred to pure waiter they 
soon diminish in size, proving that they require food and can 
digest it. The '' contractile vacuole " is believed to have the 
function of expelling the carbonic acid gas and other waste 
products of assimilation. 

This Amoeba is one of the simplest forms of the lowest 
branch of the animal kingdom, the one-celled animals or 
Protozoa ; all other animals being classed as Metazoa, as they 
are entirely built up of separate cells, which in all the more 
complex forms are countless millions in number. Every part 
of our bodies, from blood to muscles and nerves, from bones 
to skin, hair, and nails, is alike constructed of variously modi- 
fied cells. 

It might be thought that animals consisting of single cells 
could not be very numerous or very differently organised. 
Yet they are grouped into five classes, the first, Rhizopoda, 
comprising not only many kinds of Amoeba?, but the beauti- 
ful Foraminifera, whose exquisite shells are such favourite 
microscopic objects. They are single amoeboid cells which yet 
have the power either of building up shells of small inorganic 
particles, or of secreting the more beautiful shells which seem 
to mimic the forms of those of the higher Mollusca. The 
fossils called Xummulites were Foraminifera with flat coiled 
shells, forming great masses of Eocene limestone. They are 
the largest of all, some equalling a half-crown in size. 
Radiolaria are rhizopods having a beautiful siliceous skele- 
ton, and often living in colonies. Another class, the Mastigo- 
phora, have extremely varied shapes, often like sea-weed or 
flowers, having long, slender, whip-like processes. These and 
hundreds of other strange forms are still essentially single 
cells, though often grouped together for a time, and they all 



MYSTERY OF THE CELL 3G3 

increase either by division or by giving off buds, which ra[)i(lly 
grow into the perfect form. 

The remarkable thing in all these one-celled creatures is 
that they so much resemble higher animals without any of their 
organs. The writer of the article Cell iu Chambers's 
Encyclopaedia says: ''The absence of a circulating fluid, of 
digestive glands, nerves, sense-organs, lungs, kidneys, an<l the 
like, does not in any way restrict the vital functions of a 
unicellular organism. All goes on as usual, only with gi-eater 
chemical complexity, since all the different processes have but 
a nnit-mass of protoplasm in which they occur. The physi- 
ology of independent cells, instead of being very simple, must 
be very complex, just because structure or differentiation is 
all but absent." All the one-celled animals and plants go 
through a series of changes forming the cycle of their life- 
history. Beginning as a nearly globnlar quiescent cell, they 
change in form, put forth growths of various kinds, then be- 
come quiescent again and give rise to new cells by subdivi- 
sion or budding. 

This fundamental fact, that all organic life-forms begin 
with a cell and are wholly built up either by outgrowths of 
that one cell or by its continued division into myriads of 
modified cells of which all the varied organs of living things 
are exclusively formed, was first established about the year 
1840, and was declared by the eminent naturalist Louis 
Agassiz to be " the greatest discovery in the natural sciences 
in modern times." The cell is now defined as "" a nucleated 
unit-mass of living protoplasm." It is not a mere particle 
of protoplasm, but is an organised structure. We are again 
compelled to ask, Organised by what? Huxley, as we have 
seen in Chapter XV., tells us that life is the organising power ; 
Kerner termed it a vital force ; Haeckel, a cell-soul, but un- 
conscious, and he postulated a similar soul in each organic 
molecule, and even in each atom of matter. But none of these 
verbal suggestions go to the root of the matter; none of thcui 
suppose more than some ^' force," and force is a cause of 



366 THE WOKLD OF LIFE 

cell-substance. This serves to divide the chromatin elements into 
two equal parts, to separate the resulting halves from one another, 
and to arrange them in a regular manner. At the opposite poles 
of the longitudinal axis of the nucleus two clear bodies — the 
*' centrosomes/" each surrounded by a clear zone — the so-called 
'' sphere of attraction '^ — now becomes visible (A to D, cs). They 
possess a great power of attraction over the vital particles of the 
cell, so that these become arranged around them in a series of 
rays. At a certain stage in the preparation for division, the soft 
protoplasmic substance of the cell-body as well as of the nucleus 
gives rise to delicate fibres or threads ; these fibres are motile, and, 
after the disappearance of the nuclear membrane, seize the chromo- 
somes — whether these have the form of loops, rods, or globular 
bodies — with wonderful certainty and regularity, and in such a 
way that each element is held on either side by several threads from 
either pole (B, C). The chromatin elements thus immediately be- 
come arranged in a fixed and regular manner, so that they all come 
to lie in the equatorial plane of the nucleus, which we may con- 
sider as a spherical body." 

!N^ow follows another and even more remarkable stage in 
the process, which is thus described : 

" The chromatin elements then split longitudinally, and thus 
become doubled (B), as Fleming first pointed out. It must be 
mentioned that this splitting is not caused by a pull from the pole 
threads (spindle threads), which attach themselves to the chroma- 
tin-rods on both sides ; the division arises rather from forces acting 
in the rods themselves, as is proved by the fact that they are often 
ready to divide, or indeed have already done so, some time before 
their equatorial arrangement has taken place by means of these 
threads. 

" The splitting is completed by the two halves being gradually 
drawn further apart towards the opposite poles of the nuclear 
spindle, until they finally approach the centre of attraction or 
centrosome (D), which has now fulfilled its object for the present, 
and retires into the obscuritv of the cell-substance, onlv to become 
active again at the next cell-division. Each separated half of the 
nucleus now constitutes a daughter-nucleus, in which it (the 



MYSTERY OF THE CELL 367 

chromatin) immediately breaks up, and Ixvomps scattered in the 
form of minute granules in tlic delicate nuclear network, so that 
finally a nucleus is formed of exactly the same structure as that 
with which we started." 

Weismann then discusses and explains the meaning of this 
strange phenomenon. He says: 

" It is evident, as Wilhelm Koux was the first to point out, that 
the whole complex, but wonderfully exact, apparatus for the division 
of the nucleus exists for the purpose of dividing the chromatin 
substance in a fixed and regular manner, not merely quantitatively, 
but also in i-espect of the different qualities which must be contained 
in it. So complicated an apparatus wouhl have been unnecessary 
for the quantitative division only. W, however, the chromatin sub- 
stance is not uniform, but is made up of several or many different 
qualities, each of which has to be divided as nearly as possible into 
halves, or according to some definite rule, a better apparatus could 
not be devised for the purpose. On the strength of this argument 
we may, therefore, represent the hereditary substance as consisting 
of different qualities. . . . The statement that this substance 
is the hereditary substance can, therefore, hardly be considered as 
an hypothesis any longer." ^ 

After some further discussion of the views of other writers, 
he goes on to show that the chromatin substance is not only 
contained in the germ-cells, but also in all the cells of the 
entire organism in each phase of its development, which is 
effected bv the constant division of the cells and their nuclei, 
the chromatin continuing to grow during the whole time. But 
in the body it enters on a long and complex process of growth, 
so as to build up the substance of all the varied organs and 
tissues, and also for the repair or renovation of these various 
tissues as they require it. He illustrates the successive 
changes which he supposes the chromatin to bring about, and 
for which purpose it is so accurately divided and subdivided 
from the very beginning, in the following inissage: 

1 The Gcnn-Plasm, p. 29. 



368 THE WORLD OF LIFE 

"Even the two first clanghter-cells (E) which result from the 
division of the egg-cell give rise in many animals to totally different 
parts. One of them, by continued cell-division, forms the outer 
germinal layer, and eventually all the organs which arise from it, 
e. g. the epidermis, central nervous system, and sensory cells ; the 
other gives rise to the inner germinal layer and the organs derived 
from it — the alimentary system, certain glands, etc. The conclu- 
sion is inevitable that the chromatin determining these hereditary 
tendencies is different in the very first two daughter-cells." 

Later on he shows in great detail how^ similar but even 
more complex changes take place in the newly fertilised germ- 
cell in v^hich the male and female elements are combined, for 
the purpose of bringing about the accurate partition of these 
elements in all the cells which arise from them by subdivision, 
thus rendering possible the production, in all future genera- 
tions, of males and females in nearly equal proportions. He 
also shows that there is a special provision for the produc- 
tion of slight variations in successive generations in a way too 
complex to be explained here. This, of course, is largely 
speculation, but it is based at every step on observed facts 
in the processes of fertilisation and cell-division.^ 

In Professor J. Arthur Thomson's most valuable and il- 
luminating work on Heredity, in which he impartially ex- 
pounds the theories and discoveries of all the great physio- 
logical writers of the world, he gives a very high, if not the 
highest, place to those of Weismann. I will therefore quote 
from his volume Weismann's latest short statement of his 
hypothesis as to the nature of the germ-plasm ; and also Pro- 

1 The reader will see that the diagrams referred to in Weisraann's state- 
ments, quoted above, do not seem to represent accurately what he says. 
They must, therefore, be taken as " diagrams " only, not detailed " figures " 
of what is seen, which are often so complex that it is difficult to follow 
the essential details. They are for the purpose of indicating definite stages 
in the process of the development of cells up to the first cell-division. 
The small letters (jd) are not referred to in Weismann's explanation on 
the plate itself, nor in his description of what happens. But these letters 
evidently mean " idants," as explained in Professor J. A. Thomson's sum- 
mary of Weismann's theory at p. 20. 



MYSTEP.Y OF THE CELL 309 

fessor Thomson's very short summary of it, giving an explana- 
tion of Weismann's special terminology. Weismann's state- 
ment is as follows: 

" The germ-substance owes its marvellous power of development 
not only to its chemico-physical constitution, but to the fact that it 
consists of many different kinds of primary constituents, that is, 
of groups of vital units equipped witli the forces of life, and capa- 
ble of interposing actively and in a specific manner, but also 
capable of remaining latent in a passive state until they are af- 
fected by a liberating stimulus, and on this account able U) inter- 
pose successfully in development. The germ-cell cannot be merely 
a simple organism; it must be a fabric made up of many different 
organisms or units — a microcosm." ^ 

And Professor J. A. Thomson's Summary of Weismann's 
mechanics of the germ-plasm is as follows : 

Summary 

" The physical basis of inheritance — the germ-plasm — is in 
the chromatin of the nucleus of the germ-cell. 

" The chromatin takes the form of a definite number of chromo- 
somes or idants (Fig. 110, B, C, D, id). 

" The chromosomes consist of ids, each of which contains a 
complete inheritance. 

" Each id consists of numerous primary constituents or deter- 
minants. 

" A determinant is usually a group of hiophors, the minutest 
vital units. 

" The biophor is an integrate of numerous chemical molecules." 

In the preceding Summary I have italicised the technical 
terms invented by Weismann for the different stages of what 
may be called the mechanical explanation of heredity by 
means of the successive changes observed in the growing and 
dividing germ-cells. But, as he himself admits, it explains 
nothing Avithout taking for granted the essential phenomena of 
life — nutrition, assimilation, and growth; and these are ad- 
mitted to be to this day quite unexplainable. 

iThe Evolution Tlipory, trans, by J. A. Tlionison. 1004. vol. i. p. 402. 



370 



THE WORLD OF LIFE 



chr. 




^ii 




ciftr 



J) 





Fig. 110. — Diagram of Nuclear 
Division. 

A. Cell with nucleus (n) and centro- 
somes {cs) preparatory to division. 
The chromatin has become thick- 
ened so as to form a spiral thread 
(c/ir). 

B. The nuclear membrane has dis- 
appeared. Delicate threads radiate 
from the chromosomes, and form 
the "nuclear spindle," and the 
equator of which eight chromo- 
somes or nuclear loops (chr=Jd) 
are arranged; these have been 
formed by the spiral thread of 
chromatin in A becoming broken 
up. 

C. The chromosomes have each be- 
come split longitudinally into two, 
and are about to be drawn apart 

by means of the spindle threads. (For clearness four only of the eight chromo- 
somes are shown.) 

D. The daughter-loops pass towards the poles of the spindle. 

E. The cell has divided, each new cell containing a centrosome and eight nuclear 
loops. 

(From Weismann's Germ-Plasm, by permission of Walter Scott, Ltd.) 




MYSTERY OF THE CELJ. 371 

But the very first step of this process of ^^rowtli — the di- 
vision of the germ-cells, as descrihed by Weisniann himself 
and illustrated by his diagrams — is, as he himself almost ad- 
mits, equally inexplicable. He speaks of a *' complex, but 
wonderfully exact, apparatus for the division of the nucleus," 
of the purpose of that division being qualitative as well as 
quantitative, and of its evident adnptailon to the building up 
of the future body, with all its marvellous complexities, co- 
ordinations, and powers. So that the farther we go in this 
bewildering labyrinth, as expounded in his wnrlcs, in those of 
Professor Thomson, of Max ^^erworu, or in such general works 
as Parker and Haswell's Text-Book of Zoology, the more hope- 
lessly inadequate do we find the claims of Ilaeckel, Verworu, 
and their school to having made any approach whatever to a 
solution of " the riddle of the universe,'' so far as regards its 
crowning problem, the origin and development of life. 

The Plant Cell 

So far I have taken the facts as to cell-division from the 
works of zoologists only ; but almost exactly the same phe- 
nomena have been found to occur in plants, though they seem 
to have been rather more difficult to detect and unravel. In 
Professor A. Kerner's Katural History of Plants, already 
quoted, he gives the following short description of cell-di- 
vision : 

Wlien a protoplast living in a cell-cavity is about to divide into 
two, the process resulting in division is as follows : — The nucleus 
places itself in the middle of its cell, and at first characteristic lines 
and streaks appear in its substance, making it look like a ball made 
up of little threads and rods pressed together. Tliese threads 
gradually arrange themselves in positions corresponding to the 
meridian lines upon a globe: but at the place where on a globe 
the equator would lie, there then occurs suddenly a cleavage of tlie 
nucleus — a partition wall of cellulose is interposed in the gap. and 
from a single cell we have now produced a pnir of cells ■' (vol. i. 
p. 48). 



372 THE WOELD OF LIFE 

But later on we have a much fuller description, illustrated 
by four diagrammatic figures of the dividing cell, which show 
that the process in plants is substantially identical with that 
described and figured already from Weismann (vol. i. p. 
581). This is most instructive, because it shows the absolute 
identity of the fundamental mechanics of life in the animal 
and vegetable kingdoms, though their ultimate developments 
are so wonderfully diverse. 

Another interesting point is that, just as Weismann has 
stated, there is an identity in the number of certain elements 
in the cell for each species. Kemer's statement is : 

" For every species of plant the number, size, and shape of the 
bodies arising in the interior of a cell by division are quite definite, 
though they vary from species to species. In the cell-chambers of 
some species several thousand minute protoplasmic bodies arise. 
In others, again, the number is very limited. If the number is 
large the individual masses are exceedingly small, and can only be 
recognised when very greatly magnified. If the number is limited 
the divided portions are comparatively large. The shape of the 
structure is exceedingly various. Some are spherical, elliptical, or 
pear-shaped; others elongated, fusiform, filamentous, or spatulate; 
some are straight, others are spirally twisted, and many are drawn 
out into a thread; others are provided over the whole surface with 
short cilia; others, again, with a crown of cilia at a particular 
spot, or with only a single pair of long cilia. In the majority of 
cases the small bodies exhibit active movements; but sooner or 
later they come to rest, and then assume another shape or fuse 
with another protoplasmic body." 

Referring to the theory that the structure of each plant 
is due to the specific constitution of the protoplasm of the 
species, Kerner says : 

" What it does not account for is the appropriate manner in 
which various functions are distributed among the protoplasts of 
a cell-community ; nor does it explain the purposeful sequence of 
diiferent operations in the same protoplasm without any change 
in the external stimuli; the thorough use made of external ad- 



MYSTERY OF THE CELL 37U 

vantages; the resistance to injurious influences; the avoidance or 
encompassing of insuperable obstacles ; the punctuality with which 
aU the functions are performed ; the periodicity which occurs with 
the greatest regularity under constant conditions of environment ; 
nor, above all, the fact that the power of discharging all the op- 
erations requisite for growth, nutrition, renovation, and multipli- 
cation is liable to be lost. We call the loss of this power the death 
of the protoplasm" (vol. i. p. 51). 

Growth hy Cell-Division: What it Implies 

As the account now given of the most recent discoveries as 
to what actually takes place in the living cell preparatory to 
its division and subdivision, wliich are *\ 3 very first steps in 
the growth or building up of the highly complex 'and perfect 
animal or plant, is very technical, and will be perhaps unin- 
telligible to some of my readers, I will now give a very short 
statement of the process with a few illustrations, and remarks 
as to w^hat it all really means, and how" alone, in my opinion, 
it can possibly be explained. 

The egg is a single cell with a special central point or organ, 
called the nucleus, and it is this nucleus which makes the cell 
a germ-cell. That this is so has been proved in many ways, — 
in plants by grafting or hudding, where the ilower-bud which 
contains a germ-cell, when inserted in the bark of a differ- 
ent variety, and sometimes a different species of plant, repro- 
duces the exact kind of flower or fruit that characterised the 
tree or bush the bud was taken from, not that of the plant of 
which it now^ forms a part, and whose sap forms its nourish- 
ment. 

Again, Professor Boveri deprived an Qgg of a species of 
sea-urchin {Echinus microtuherculatus) of its nucleus, and 
then fertilised the egg with the spermatozoa of anotlier species 
{Sphcerechiiiu^ qranidaris). The egg so treated developed 
larva? with the true characters of the latter species only, so 
that the main substance of the egg provided nutriment for 
the offspring, but did not transmit to it any of it^ parental 



a7i THE WOELD OF LIFE 

characters. A similar illustration, at a later period of life, is 
that of an infant Avhich from birth is fed on cow's milk, yet, 
if it lives, possesses only human characteristics. 

This nucleus^, therefore, which, when fertilised, has such 
marvellous powers and properties, is tlie seat of heredity and 
development. What is it that gives it this power ? What 
is the agency that sets in motion a whole series of mechanical, 
chemical, and vital forces, and guides them at every step to 
their destined end ? Again, I urge, let us consider what we 
have to explain. The matter of the fertilised egg is the mil- 
lionfold complex substance called protoplasm. It is also 
mainly living protoplasm. AVhat power gave it life ? It is 
also (in its essential part, the nucleus) already highly differ- 
entiated — it is organised 'protoplasm. What poiver organ- 
ised it ? It is a liquid or semi-liquid substance with slight 
cohesion ; it gradually forms a cell, which divides and sub- 
divides, till at a certain point the globular mass or layer of cells 
bends inward upon itself, forming a hollow sac with outer and 
inner walls. What power determines the cell-mass to take 
this or other well-defined shapes ? Then, as cell-division and 
specialisation go on, the rudiments of muscle and bone are 
formed with totally distinct properties — the one with im- 
mense contractility and tensile strength, the other with great 
hardness and rigidity. Who or what guides or determines 
the atoms of the protoplasmic molecules into these new comibi- 
nations chemically, and new structures mechanically ? — com- 
binations and structures which all the chemists and physicists 
of the world are powerless to produce even when they have the 
ready-formed protoplasm given them to start with ? Then as 
the process goes on in an ever-increasing complexity which 
baffles the microscope of the observer to follow, never diverg- 
ing at any one point from the precise mode of change which 
alone leads on to the completed living organism, we are asked 
to be satisfied with millions of ^^ gemmules," " fundamental 
units," " determinants," etc., which actually do build up the 



MYSTEKY OF THE CELL 375 

living body of each organism in a prescribed and lUK-liangcable 
sequence of events. But this orderly process is quite unintel- 
ligible without some directive org,anising power constantly at 
work in or upon every chemical atom or physical niolcculv of 
the whole structure, as one after another they are brought to 
their places, and built in, as it were, to the structure of every 
tissue of every organ as it takes form and substance in tlie 
fabric of the living, moving, and, in the case of animals, sensi- 
tive creation. 

I will conclude this short sketch of cell-life and its mystery, 
with a picturesque account of one striking example in the ani- 
mal world, from Professor Lloyd Morgan's illuminating vol- 
ume. 

There is, perhaps, no more wonderful instance of rapid and 
vigorous growth than the formation of the antlers of deer. These 
splendid weapons and adornments are shed every year, in the 
spring, when they are growing, they are covered over with a dark 
skin provided with short, line, thick-set hair, and technically termed 
" the velvet.'^ If you lay your hand on the growing antler, you will 
feel that it is hot with the nutrient blood that is coursing beneath 
it. It is, too, exceedingly sensitive and tender. An army of tens 
of thousands of busv livinor cells is at work beneath that velvet 
surface, building the bony antlers, preparing for the battles of 
autunm. Each minute cell knows its work, and does it for llie 
general good — so perfectly is the body knit into an organic whole. 
It takes up from the nutrient blood the special materials it requires ; 
out of them it elaborates the crude bone-stuff, at first soft as wax, 
but ere long to become as hard as stone; and then, having done iis 
work, having added its special morsel to the fabric of the antler, it 
remains imbedded and immured, buried beneath the bone prodiRis 
o": its successors or descendants. No hive of Ijccs is busier or more 
replete with active life than the antler of a stag as it grows ])eneatli 
the soft warm ' elvet. And thus are built up in the eoiirsp of a few 
weeks those splendid "beams" with their " tynos '' and "snags," 
which, in the case of the wapiti, even in the continomont of the 
Zoological Gardens, may reach a weight of thirty-two ]>ounds, and 



376 THE WOKLD OF LIFE 

which, in the freedom of the Eocky Mountains, may reach such a 
size that a man may walk without stooping through the archway 
made by setting up upon their points tlie shed antlers. 

In the eastern European forests the horns of the red deer 
reach a w^eight of 74 pounds, while in the recently extinct Irish 
elk the large, broadly palmated horns sometimes reached an 
expanse of 11 feet. These remarkable weapons were devel- 
I oped both for combats between the males and as a means of pro- 
\ tecting the females and young from enemies. As organic out- 
growths they are extremely simple when compared with the 
feathers of the bird or the scales of a butterfly's wing; yet as 
exemplifying the need for some guiding power, exerted upon 
the individual cells which carrv out the work with such won- 
derful precision every year, they are equally striking. The 
blood, we know, furnishes the materials for every tissue in the 
body; but here a large mass of bony matter, covered with a 
thin skin and dense hair, is rapidly built up, to a very definite 
form in each species; then the skin and hair cease growing 
and fall away, while the horns persist for nearly a year, when 
they, too, fall off and are again renewed. 

Concluding Remarks on the Cell-Prohlem 

The very short account I have now given of w^hat is known 
of the essential nature, the complex structure, and the alto- 
gether incomprehensible energies of these minute unit-masses 
of living matter, the cells — so far as possible in the very words 
of some of the most recent authorities — must, I think, con- 
vince the reader that the persistent attempts made by llaeckel 
and Yerw^oru to minimise their marvellous powers as mere re- 
sults of their complex chemical constitution, are w^holly un- 
availing. They are mere verbal assertions which prove noth- 
ing; w^hile they afford no enlightenment wdiatever as to the 
actual causes at work in the cells leading to nutrition, to growth, 
and to reproduction. 

Very few of the workers who have made known to us the 



MYSTEKY OF THE CELL 377 

strange phenomena of cell-life in liie Protozoa, and of cell- 
division in the higher animals and plants, seem to think any- 
thing about the hidden causes and forces at work. They are 
so intensely interested in their discoveries, and in following 
out the various chani^es in all their ramitications, that tliev 
have no time and little inclination to do more than add con- 
tinually to their knowledge of the facts. And if one attempts 
to read through anv ffood text-book such as Parker and Has- 
well's Zoology, or J. Arthur Thomson's Heredity, it is easy to 
understand this. The complexities of the lower forms of life 
are so overwhelming and their life-histories so mysterious, and 
yet they have so much in common, and so many cross-affinities 
among the innumerable new or rare species continually being 
discovered, that life is not long enough to investigate the struc- 
ture of more than a very small number of the known forms. 
Hence very few of the writers of such books express any opin- 
ion on those fundamental problems which Haeckel and his fol- 
low^ers declare to have been solved by them. All questions of 
antecedent purpose, of design in the course of development, or 
of any organising, directive, or creative mind as the funda- 
mental cause of life and organisation, are altogether ignored, 
or, if referred to, are usually discussed as altogether imscien- 
tific and as showing a deplorable want of confidence in the 
powers of the human mind to solve all terrestrial problems. 

If, as I have attempted to do here, we take a broad and com- 
prehensive view of the vast world of life as it is spread out be- 
fore us, and also of that earlier world which goes back, and 
ever further back, into the dim past among the relics of pre- 
ceding forms of life, tracing all living things to more gen- 
eralised and usually smaller forms; still going back, till one 
after another of existing families, orders, and even classes, of 
animals and plants either cease to appear ur are represented 
only by rudimentary forms, often of types tpiite unknown to 
us; we meet with ever greater and greater ditiiculties in dis- 
pensing with a guiding purpose and an immanent creative 
powder. 



378 THE WOKLD OF LIFE 

For we are necessarily led back at last to the beginnings of 
life — to that almost infinitely remote epoch myriads of years 
before the earliest forms of life we are acquainted with had 
left their fragmentary remains in the rocks. Then, at some 
definite epoch, the rudiments of life must have appeared. But 
whenever it began, whenever the first vegetable cell began its 
course of division and variation ; and when, very soon after, 
the animal cell first appeared to feed upon it and be developed 
at its exj)ense, — from that remote epoch, through all the ages 
till our own day, a continuous, never-ceasing, ever-varying 
process has been at work in the two great kingdoms, vegetal 
and animal, side by side, and always in close and perfect 
adaptation to each other. 

Myriads of strange forms have appeared, have given birth 
to a variety of species, have reached a maximum of size, and 
have then dwindled and died out, giving way to higher and 
better-adapted creatures ; but never has there been a complete 
break, never a total destruction, even of terrestrial forms of 
life ; but ever and ever they became more numerous, more varied, 
more beautiful, and hetler adapted to tJie wants, the 'material 
'progresSj, the higher enjoyments of mankind. 

The whole vast series of species of plants and animals, with 
all their diversities of form and structure, began at the very 
dawn of life upon the cooling earth with a single cell (or with 
myriads of cells) such as those whose structure and properties 
we have here been considering; and every single individual of 
the myriads of millions Avhich have ever lived upon the earth 
have each begun to be developed from a similar but not idm- 
tical cell ; and all the possibilities of all their organs, and 
structures, and secretions, and organic products have arisen out 
of such cells; and we are asked to believe that tliese cells and 
all their maiwellous outcome are the result of the fortuitous 
clash of atoms with the help of '^ an unconscious cell-soul of 
the most primitive and rudimentary kind ! " 



MYISTEKV OF THE CELL 3Tti 

The Fallacy of Eternity as an Explanation of Evolution 

It may perhaps not be out of place here to deal with what 
seems to me to be one of the common philosophical fallacies of 
the present day, the iilea that you can get over the difficulty 
of requiring any supreme mind, any author <jf the cosmos, by 
assuming that it had no beginning — that it has existed, with 
all its forces, energies, and laws, from all eternity, and thai it 
^vill continue, to exist for all eternity. 

I have already quoted llaeckel and some others on this 
point. I will now give a similar statement by two writers of 
to-day. Dr. Saleeby in an article on The Life of the Uni- 
verse, in The Academy (March 25, 1905), after discussing 
the theory of dissipation of energy, the infinity of the uui- 
verse, the littleness of man, and other matters, with his usual 
clearness and vigour, concludes with this sentence : '' Radium- 
clocks have been made that will go for a million years ; but I 
believe that the Universe was never made and will go on for 
ever." This, of course, is vague, because, if the term "' uni- 
verse '' is taken to mean " the all that exists," or rather, '' all 
that exists, that ever has existed, or that ever will exist,'' it is 
a truism, because that includes all life and God. But " uni- 
verse " is taken bv llaeckel and his school to mean the ma- 
terial universe, and to definitely exclude spirit and god. 

A great modern physicist. Professor Svanto Arrhenius, in 
the preface to his recent work. Worlds in the ^Making, con- 
cludes thus: 

"My guiding principles in this exposition of cosinogonic pi-(.h- 
lems has been the conviction that the Universe in its csseiico luis 
always been what it is now. Matter, energy, and life iiavo only 
varied as to shape and position in space." 

This will be taken to mean, and T presume does mean, 
"matter" and "life" as we know them on the earth, and to 
exclude, as Haeckol does drfinitely, spirit and deity. The 
general conception of all these writers seems to be, that it is 



380 THE WORLD OF LIFE 

easier, simpler, more scientific, to assume that '^ matter, 
energy, and life " as we see them, have existed, the same in 
essence though in ever varying forms, from all eternity, and 
will continue to exist to all eternity, than to assume any intel- 
ligent power beyond what we see. 

Xow the idea, that positing eternity for matter and for or- 
ganised life, and for all the forces of nature, overcomes diffi- 
culties or renders their existence at the stage they have now 
reached at all intelligible, is, I maintain, the very opposite of 
the truth, and arises from a want of real thought as to what 
" eternity " means. Take, first, " life " culminating in 
" man." It is admitted that there has been a continuous 
though not uniform progress from the first organic cell up to 
man. To arrive at that end it has admittedly occupied a very 
large portion of the duration of the habitability of the planet, 
and of the sun as a heat and life-giver. It is also assumed 
that, to ensure the persistence of life w^hen suns cool and planets 
are unsuitable, either the germs of life must be carried through 
space (at the zero of temperature) from one solar system to 
another till they chance to alight upon one where the condi- 
tions of life are suitable, or they must have developed again 
out of dead matter. All this is overwhelmingly difficult, — but 
let us grant it all. Let us grant also that there are forces and 
energies capable of automatically building up progressively 
developing forms of sentient life, such as have been built up 
on the earth. Then, if these forces and energies have acted 
from all eternity, they must have resulted in an infinite life- 
development, that is, in beings inconceivably higher than we 
are. Now we, who, as they all tell us, are poor miserable 
creatures of a day, have yet got to know much of the universe, 
to apply its forces, and thus to modify nature — so, an eternity 
of progress at the same rate (and as there is progress there is 
no cause why it should stop) must necessarily have produced an 
infinite result — that is, beings which as compared with us 
Avould be gods. And as you cannot diminish eternity, then 



MYSTERY OF THE CELL 381 

long ages before the first rudiment of life appeared npon the 
earth, long before all the suns we see had l>eeonie suns, the in- 
finite development had been at work and must liavc ])r(>diic(Ml 
gods of infinite degrees of powei-, any one of whom would pre- 
sumably be quite capable of starting such a solar system as 
ours, or one immensely larger and better, and of so determin- 
ing the material constitution of an " earth " as to initiate and 
guide a course of development which would have resulted in 
a far higher being than man. Once assume a mind-developing 
power from all eternity, and it must, noiu, and at all earlier 
periods of the past have resulted in beings of infinite power — 
what we should term — Gods ! 

It may, I think, be stated generally, that whatever has an 
inherent power of increase or decrease, of growth, develop- 
ment, or evolution, cannot possibly have existed from a past 
" eternity '' unless the law of its evolution is an ever-recurrent 
identical cycle, in which case, of course, it may, conceivably, 
have existed from eternity and continue through an eternity of 
future cycles, all identical; and, therefore, such cycles could 
never produce anything that had not been produced an in- 
finite number of times before. Is this a satisfactory outcome 
for an eternal self-existent universe ? Is this easier, simpler, 
more rational, more scientific, more philosophical, than to 
posit one supreme mind as self-existent and eternal, of which 
our universe and all universes are the manifestations I And 
yet the " infinity and eternity " men call themselves ^' monists,'^ 
and claim to be the only logical and scientific thinkers. With 
them matter, ether, life — (surely three absolutely distinct 
things) — with all the wonderful laws, and forces, and direc- 
tive agencies which they imply, and without which none of 
them could for a moment exist, all are to be accounted for and 
explained by the one illogical assumption, their eternity ; the 
one complete misnomer, monism ; the one alleged fundamental 
law which explains nothing, the " law of substance." 

It will be seen that this alleged explanation — the eternal 
material universe — does not touch the necessitv, becominc: 



382 THE WORLD OF LIFE 

more clear every day, not for blind laws and forces, but for 
immanent directive and organising mind, acting on and in 
every living cell of every living organism, during every moment 
of its existence. I think 1 have sufficient! v shown that with- 
ont this, life, as we know it, is altogether unthinkable. Xo 
^^ eternal " existence of matter will make this in the remotest 
defifree imaginable. It is this difficultv which the ^^ monists '' 
and the " eternalists " of the Llaeckel and Verworu type abso- 
lutely shirk, putting us off ^vith the wildest and most contra- 
dictory assertions as to what they have proved ! 

I venture to hope and to believe that such of my readers 
as have accompanied me so far through the present volume, 
and have had their memory refreshed as to the countless 
marvels of the world of life ; culminating in the two great 
mysteries — that of the human intellect wdth all its powers 
and capacities as its outcome, that of the organic cell with 
all its complexity of structure and of hidden powers as its 
earliest traceable origin — will not accept the loud assertion, 
that everything exists because it is eternal as a sufficient or a 
convincing explanation. A critical examination of the sub- 
ject demonstrates, as the greatest metaphysicians agree, that 
everything but the Absolute and Unconditioned must have had 
a beginning. 



CHAPTER XVIII 

THE ELEMENTS AND WATER, IN RELATION TO THE LIFE-WORLD 

I HAVE already (in Chapter XVI.) given the statements of 
two continental physiologists as to great chemical complexity 
of the proteid molecule, involving as it does, in certain cases 
already studied, a combination of about two thousand chemical 
atoms. A more recent authority (Mr. W. Bate Hardy) is of 
opinion that this molecule really contains about thirty thou- 
sand atoms, while the most complex molecule known to the 
organic chemist is said to contain less than a hundred. One 
of the results of this extreme complexity is that almost all the 
products of the vegetable and animal kingdoms are what are 
termed hydro-carbons, that is, they consist of compounds of 
carbon, with hydrogen, oxygen, or nitrogen, or any or all of 
them, combined in an almost infinite variety of ways. Yet 
the compounds of these four elements already known are more 
numerous than those produced by all the other elements, more 
than seventy in number. 

This abundance is largely due to the fact that the very same 
combination of carbon with the three gaseous constituents of 
the carbon-compounds often produces several substances very 
different in appearance and properties. Thus dextrine (or 
British gum), starch, and cellulose (the constituents of the 
fibres of plants) all consist of six atoms of carbon, ton of 
hydrogen, and five of oxygen ; yet they have very different 
properties, cellulose being insoluble in water, alcohol, or ether ; 
dextrine soluble in water but not in alcohol ; while starch is only 
soluble in Avarm water. These differences are supposed to be 
due to the different arrangement of the atoms, and to their being 
combined and recombinod in dift'orent ways; and as the more 
atoms are used, the possible complexity of these arrangements 

383 



384 THE WORLD OF LIFE 

becomes greater, and the vast numbers and marvellous diversity 
of the organic compounds becomes to some extent intelligible. 
Professor Kerner, referring to the three substances just men- 
tioned, gives the following suggestive illustration of their 
diverse properties, of which I have only mentioned a few. He 
says : 

" If six black, ten blue, and five red balls are placed close to- 
gether in a frame, they can be grouped in the most diverse ways 
into beautiful symmetrical figures. They are always the same 
balls, they always take up the same space, and yet the effect of the 
figures produced by the different arrangements is wholly distinct. 
It may be imagined, similarly, that the appearance of the whole 
mass of a carbon-compound becomes different in consequence of 
the arrangement of the atoms, and that not only the appearance 
but even the physical properties undergo striking alterations." 

Another and perhaps more interesting example, illustrated 
by a diagram, is given by Mr. W. Bate Hardy in his lecture 
already referred to. He says : 

" Here is a simple and startling case. The molecules of two 
chemical substances, benzonitrile and phenylisocyanide, are com- 
posed of seven atoms of carbon, five of hydrogen, and one of 
nitrogen : 

N C 

H— C I 1 C— H H— C I I C— H 

H— C I I C— H H— C I I C— H 

c c 

Benzonitrile. Phenylisocyanide. 

The only difference in the arrangement of the atoms is that those 
of nitrogen and carbon are reversed. But the properties of these 
two substances are as unlike as possible. The first is a harmless 
fluid with an aromatic smell of bitter almonds. The second is 
very poisonous, and its odour most offensive." 



THE ELEMENTS AXl) LIFE 385 

Here only three elements are combined, and in identical pro- 
portions. We can imagine, therefore, what endless diversities 
arise when to these are added anv of nine other elements, and 
these in varying proportions, as Avell as being groii])ed in every 
possible manner. 

The fact of ^^ isomerism," or of different substances, often 
with very different properties, having the very same chemical 
composition, is now so familiar to chemists as to excite com- 
paratively little attention, yet it is really a marvel and a mys- 
tery almost equal to that of the organic cell itself. It is 
probably dependent upon the highly complex nature of the 
molecules of the elements, and also of the atoms of which these 
molecules are built up; while atoms themselves are now be- 
lieved to be complex systems of electrons, which are held to be 
the units of electricity and of matter. It is these electrons 
and their mysterious forces that give to matter all its mechan- 
ical, physical, and chemical properties, including those which, 
in the highly complex protoplasm, have rendered possible that 
whole world of life we have been considering in the present 
volume. 

Here, then, we find, as before, that the further back we go 
towards the innermost nature of matter, of life, or of mind, 
we meet with new complications, new forces, new agencies, all 
pointing in one direction towards the final outcome — the buikl- 
ing up of a living sentient form, which should be the means 
of development of the enduring spirit of man. 

Important and Unimportant Elements 

If we look at the long list of between seventy and eighty 
elements now known we shall see that a comparatively suuill 
number of these (less than one-fourth) seem to play any im- 
portant part either in the structure of the earth as a phinet, 
or in the constitution of the organised l)eings that have been 
developed upon it. The most important of the elements is 
oxygen, which is not only an essential in the structure of all 
living things, but forms a large part of the air and the water 



386 THE WORLD OF LIFE 

which are essential to their contiiiTied existence. It is also a 
constituent of almost every mineral and rock, and is estimated 
to form about 47 per cent of the whole mass of the globe. The 
next most abundant elements are silicon, aluminium, and iron, 
which form 25, 8, and 7 per cent respectively of the earth- 
mass. Then follow calcium, magnesium, sodium, and potas- 
sium, contributing from about 4 to 2 per cent of the whole; 
while no other element forms so much as one per cent, and the 
majority probably not more than one-fiftieth or one-hundredth 
of one per cent. 

The gases, hydrogen and nitrogen, are, however, exceedingly 
important as forming with oxygen the atmosphere and the 
oceans of the globe, which by their purely physical action on 
climate, and in causing perpetual changes on the earth's sur- 
face, have rendered the development of the organic w^orld pos- 
sible. These ten elements appear to be all that were necessary 
to constitute the earth as a planet, and to bring about its varied 
surface of mountain and valley, rivers and seas, volcanoes and 
glaciers ; but in order to develop life, and thus clothe the earth 
with ever-growing richness of vegetation and ever-changing 
forms of animals to be sustained by that vegetation, four other 
elements were required — carbon, sulphur, phosphorus, and 
chlorine — but these being either gaseous or of very small spe- 
cific gravity, and thus existing (perhaps exclusively) near the 
earth's surface, comparatively little of them was needed. 



Elements in Protoplasm in Order of their 
Abundance {approximately). 



1. 


Hydrogen 


2. 


Carl) 011 


3. 


Oxvgen 


4. 


Nitrogen 


5. 


Sulphur 


6. 


Iron 




Phosphorus 


8. 


Chlorine 


9. 


Sodium 


10. 


Potassium 


11. 


Calcium 


12. 


Magnesium 



List of the More Important Elements 

Elements in the Earth in Order of their 
Quantity {approximately). 

per cent. 

1. Oxygen 47 

2. Silicon 25 

3. Aluminium 8 

4. Iron 7 

5. Calcium 4 

6. Magnesium 3 

7. Sodium 2.5 

8. Potassium 2.5 

9. Hydrogen (?) 0.1 

10. Nitrogen (?) 0.1 

All others (?) 0.8 



100 



THE ELEME:N^TS AXD life 387 

The two elements in italics — iiilicoit and Alumijiiuni — altlioiii:li form- 
ing a large proportion of the earth's substance, are not ctmcndal constitu- 
ents of protophism, although occasionally forming part of it. 

In the list of the more important elements here given, I 
have arranged them in two series, the first showing the essential 
constituents of protoplasm ; the second showing the ten which 
are the most important constituents of the earth's mass as 
known to geologists and physicists. The four which are itali- 
cised in the first list do not appear in the second, and cannot, 
therefore, be considered as forming an essential portion of the 
rock-structure of the earth, although without them it seems 
fairly certain that the life-world could not have existed. 

The Elements in relation to Man 

So far as we can see, therefore, the fourteen elements in 
these two lists would have sufficed to brine: about all the essen- 
tial features of our earth as w^e now find it. All the others 
(more than sixty) seem to be surplusage, many exceedingly 
rare, and none forming more than a minute fraction of the 
mass of the earth or its atmosphere. All except seven of these 
are metals, including (with iron) the seven metals known to 
the ancients and even to some prehistoric races. The seven 
ancient metals are gold, silver, copper, iron, tin, lead, and mer- 
cury. All of these are widely distributed in the rocks. They 
are most of them found occasionally in a pure state, and are 
also obtained from their ores without much difficulty, which 
has led to their being utilised from very early times. But 
though these metals (except iron) appear to serve no important 
purpose either in the earth itself or in tlie vegetable or animal 
kingdoms, they have yet been of very gTcat importance in the 
history of man and the development of civilisation. From very 
remote times gold and silver have been prized for their extreme 
beauty and comparative rarity; the search after them has led 
to the intercourse between various races and peoples, and to 
the establishment of a world-wide conmierce ; wliile the facility 
W'ith wdiich they could be worked and polished called fortli the 



388 THE WORLD OF LIFE 

highest powers of the artist and craftsman in the making of 
ornaments, coins, drinking-vessels, etc., many of which have 
come down to ns from early times, sometimes showing a beauty 
of design which has never been surpassed. Our own earliest 
rudiments of civilisation were probably acquired from the 
Phoenicians, who regularly came to Cornwall and our southern 
coasts to purchase tin. 

Each of the seven metals (and a few others now in com- 
mon use) has very special qualities which renders it useful for 
certain purposes, and these have so entered into our daily life 
that it is difficult to conceive how we should do without them. 
Without iron and copper an effective steam-engine could not 
have been constructed, our whole vast system of machinery 
could never have come into existence, and a totallv distinct 
form of civilisation would have developed — perhaps more on 
the lines of that of China and Japan. Is it, we may ask, a 
pure accident that these metals, with their special physical 
qualities which render them so useful to us, should have ex- 
isted on the earth for so many millions of years for no appar- 
ent or possible use ; but becoming so supremely useful when 
Man appeared and began to rise tow^ards civilisation ? 

But an even more striking case is that of the substances 
which in certain combinations produce glass. Sir Henry Ros- 
coe states that silicates of the alkali metals, sodium and potas- 
sium, are soluble in water and are non-crystalline ; those of 
the alkaline earths, calcium, etc., are soluble in acid and are 
crystalline; but by combining these silicates of sodium and 
calcium, or of potassium and calcium, the result is a substance 
which is noi soluble either in water or acids, and which, when 
fused forms glass, a perfectly transparent solid, not crystallised 
but easily cut and ]3olished, elastic within limits, and when 
softened by heat capable of being moulded or twisted into an 
endless variety of forms. It can also be coloured in an infinite 
variety of tints, while hardly diminishing its transparency. 

The value of cheap glass for windows in cold or changeable 
climates cannot be over-estimated. Without its use in bottles, 



THE ELEMENTS AXD LIEE 389 

tubes, etc., chemistry could hardly exist ; while astronomy could 
not have advanced beyond the stage to which it had Itecn 
brought by Copernicus, Tycho Brahe, and Kepler. It rfu- 
dered possible the microscope, the telescope, and the si)ectro- 
scope, three instruments without which neither the starry heav- 
ens nor the myriads of life-forms would have had their inner 
mysteries laid open to us. 

One more example of a recent discovery of one of the rarest 
substances in nature — radium — and its extraordinarv effects, 
points in the same direction. So far as known at present, this 
substance may or may not be in any way important either 
to the earth as a planet or for the development of life upon 
it ; but the most obvious result of its discovery seems to bo 
the new light it throws on the nature of matter, on the con- 
stitution of the atom, and perhaps also on the mysterious ether. 
It has come at the close of a century of wonderful advance 
in our knowledge of matter and the mysteries of the atom. 
Many other rare elements or their compounds are now being 
found to be useful to man in the arts, in medicine, or by the 
light they throw on chemical, electrical, or ethereal forces.^ 

If now we take the occurrence of all these apparently use- 
less substances in the earth's crust ; the existence in tolerable 
abundance, or very widely spread, of the seven metals known 
to man during his early advances towards civilisation, and the 
many ways in which they helped to further that civilisation ; 
and, lastly, the existence of a few elements which, when spe- 
cially combined, produce a substance without which modern 
science in almost all its branches would have been impossible, 
w^e are broui2:ht face to face with a body of facts which are 
wholly unintelligible on any other theory than that the earth 
(and the universe of which it form> a part) was constituted 

1 While this chapter is being written I see it announced that two of the 
rarest of the elements, lanthanium and noodyniuin. have l)ei'n found to pro- 
vide (through some of their comjiounds) light-lilters, which increase the 
efficiency of the spectroscope in <1h» study of the planetary atmospheres, 
and may thus be the menus of still furthoi- extending oiu* knowledge of the 
universe. 



390 THE WOKLD OF LIFE 

as it is in order to supply us, when the proper time came, with * 
the means of exploring and studying the inner mechanism 
of the world in which we live — of enabling us to appreciate 
its overwhelming complexity, and thus to form a more ade- 
quate conception of its author, and of its ultimate cause and 
purpose. 

I have already shown that the postulate of a past eternal 
existence is no explanation, and leads to insuperable difficulties. 
A beginning in time for all finite things is thus demonstrable ^ 
but a beginning implies an antecedent cause, and it is impos- 
sible to conceive of that cause as other than an all-pervading 
mind. 

The Mystery of Carbon: the Basis of Organised Matter and 

of Life 

It is universally admitted that carbon is the one element 
which is essential to all terrestrial life. It will be interesting, 
therefore, to give a brief statement of what is known about 
this very important substance. Although it is so familiar to 
us in its solid form as charcoal, or in a more mineralised form 
as black-lead or graphite, it is doubtful whether it exists un- 
combined on the earth except as a product of vegetation. 
Though graphite (plumbago) is found in some of the earliest 
rocks, yet it is believed that some forms of vegetation existed 
much earlier. Graphite has also occurred (rarely) in mete- 
orites, but I am informed by my friend. Professor Meldola, 
that it cannot be decided whether this is derived from carbon- 
dioxide gas or from gaseous carbon. Sir William Huggins 
was also doubtful as to the state in Avhich it exists in the sun 
and comets, w^hether as carbon-vapour or a hydrocarbon. But 
the most interesting point for us is that it exists as a constitu- 
ent of our atmosphere, of which carbon-dioxide fonns about 
^■g^ooth part, equal to about yoVo't^^ ^2iYi by weight of solid 
carbon ; and it is from this that the whole of the vegetable 
kingdom is built up. The leaves of plants contain a green 
substance named chlorophyll, which by the aid of sunlight can 



THE ELEMENTS AND JJFE 391 

extract the carbon from the gas, and there is no other means 
known hj which this can be done at ordinary temperatures. 
The chemist has to use the electric spark, or very high tem- 
peratures, to perform what is done by the green leaves at the 
ordinary temperatures in which we live. 

The reverse operation of combining carbon with other ele- 
ments is equally difficult. In Chambers's Encyclopaedia we 
find the following statement: '^ At ordinary temperatures all 
the varieties of carbon are extremely unalterable ; so much so 
that it is customary to burn the ends of piles of wood whirh 
are to be driven into the ground, so that the coating of non- 
decaying carbon may preserve the inner wood. Wood-charcoal, 
however, burns very easily, animal charcoal less so ; then fol- 
low in order of difficulty of combustion coke, anthracite, black- 
lead, and the diamond." The two latter withstand all tem- 
peratures, except the very highest obtainable. These various 
states of carbon differ in other respects. Ordinary carbon is 
a good conductor of electricity; the diamond is a non-con- 
ductor. 

Carbon unites chemically with almost all the other elements, 
either directly or by the interv^ention of some of the gases. It 
also possesses, as Sir Henry Roscoe says : " A fundaiTiental and 
distinctive quality. This consists in the power which this ele- 
ment possesses, in a much higher degree than any of the others, 
of uniting with itself to form complicated compounds, contain- 
ing an aggregation of carbon-atoms united with either oxygen, 
hydrogen, nitrogen, or several of these, bound together to form 
a distinct chemical Avhole.'' 

Carbon is also the one element that is never absent from 
any part or product of the vegetable or animal kingdoms ; and 
its more special property is that, when combined with hydro- 
gen, nitrogen, and oxygen, together with a small quantity 
(about 1 per cent) of sulphur, it forms the whole group <if 
substances called albuminoids (of which white of egg is the 
type), and which, much diluted, forms the essential part of 
the blood, from which all the solids and fluids of organisms 



392 THE WORLD OF LIFE 

are secreted. It was on these special features of carbon that 
Haeckel founded his celebrated carbon-theory of life, which 
he has thus stated : '^ The peculiar chemico-physical properties 
of carbon — especially the fluidity and the facility of decom- 
position of the most elaborate albuminoid compounds of car- 
bon — are the sole and the mechanical causes of the specific 
phenomena of movement, which distinguish organic from in- 
organic substances, and which are called life, in the usual sense 
of the word.'' And he adds : " Although this ' carbon-theory ' 
is warmly disputed in some quarters, no better monistic theory 
has yet appeared to replace it." 

What a wonderfully easy way of explaining a mystery! 
Carbon forms a constituent of the bodies and of the products 
of all living things ; therefore carbon is the cause of life and all 
its phenomena ! 

But besides the carbon in the atmosphere an immense quan- 
tity exists in the various limestone rocks, consisting of car- 
bonate of lime (CaCOg). It is quite possible, however, that 
these are all results of animal secretions as in coral-reefs; or 
of the debris of the hard parts of marine animals, as in the 
Globigerina-ooze. Limestones exist among the oldest rocks, 
but as we know that marine life was very much older, this is 
no objection. All water holds in solution a large quantity of 
carbonic acid gas, so that both air and water are the source 
of the most essential elements for building up the bodies of 
plants and animals. 

The ocean also holds a large amount of carbonate of lime 
in solution, and this is kept permanently dissolved by the large 
amount of carbonic acid gas always present, which is sufficient 
to dissolve five times the amount of carbonate of lime which 
actually exists. Deposits of inorganic limestone are, there- 
fore, now never formed except by long-continued evaporation 
in isolated bodies of salt water. This renders it more probable 
that all pure limestone rocks are really very ancient coral-reefs 
consolidated and crystallised by heat and pressure under masses 
of superincumbent strata. 



THE ELEMENTS AMJ EIFE ;]U0 

The altogether remarkable and exceptional properties of 
carbon are fully reeognised by modern chemists, as well shown 
by Professor II. E. Armstrong's statements in his Presidential 
Address to the British Association in lUU'J : 

"The central luminary of our system, let me insist, is the ele- 
ment carbon. The constancy of this element, the firmness of its 
affections and affinities, distinguishes it from all others. It is only 
when its attributes are understood that it is possible to frame any 
proper picture of the possibilities which lie before us of the place of 
our science in the cosmos." 

And a little further on he says: 

" Our present conception is, that the carbon atom has tetrahodral 
properties in the sense that it has four affinities which operate 
practically in the direction of four radii proceeding from the centre 
towards the four solid angles of a regular tetrahedron. . . . 
The completeness with which the fundamental properties of the 
carbon atom are symbolised by a regular tetrahedron being alto- 
gether astounding." 



And again : 

" It would seem that carbon has properties which are altogether 
special; the influence which it exerts upon other elements in de- 
priving them of their activity is so remarkable." 

We see, therefore, that carbon is perhaps the most unique, 
in its physical and chemical properties, of the whole series of 
the elements, and so far as the evidence points, it seems to 
exist for the one purpose of rendering the development of 
organised life a possibility. It further appears that its unique 
chemical properties, in combination with those of the other 
elements which constitute protoplasm, have enabled the various 
forms of life to produce that almost infinite variety of sub- 
stances adapted for man's use and enjoyment, and especially 
to serve the purposes of his ever-advancing research into the 
secrets of the universe. 



3yi THE WOELD OF LIFE 

Water: its relations to Life and to Man 

The compound water is as essential for building up living 
organisms as is carbon, and it exhibits peculiarities almost 
as striking as those of that element. Its more obvious quali- 
ties are singularly unlike those of its components, oxjgen and 
hydrogen : oxygen supports combustion, water checks or destroys 
it; hydrogen burns readily, water is incombustible. Water is 
wonderfully stable at ordinary temperatures, hence it is the 
most innocuous of fluids ; it is also an almost universal solvent, 
hence its great value in cookery, in the arts, and for cleansing 
purposes. Besides being absolutely essential for vegetable and 
animal life it has qualities which render it serviceable to civil- 
ised man, both in his pleasures and his scientific discoveries. 
Absolutely pure water is a non-conductor of electricity; but as 
all natural waters contain gases or salts in solution, it then be- 
comes a conductor, and is partly decomposed, or becomes an 
electrolyte. The various curious facts connected with water 
are so puzzling, that in April 1910 the Faraday Society held 
a general discussion in order to arrive at some solution of what 
is termed in the Electrical Review " the most complex of prob- 
lems." One of the facts that seem to be now generally 
accepted is, that water is not the simple compound, H2O, it 
is usually held to be, but is really a compound of three hydrols, 
II2O being gaseous water, (H20)3 being ice, while liquid water 
is a mixture of these or (H20)2. 

Professor H. E. Armstrong put forward this view in 1908, 
and in the Address already quoted he says: 

" Although it is generally admitted that water is not a uniform 
substance but a mixture of units of different degrees of molecular 
complexity, the degree of complexity and the variety of forms is' 
probably under-estimated, and little or no attention has been paid 
to the extent to which alterations produced by dissolving substances 
in it may be the outcome and expression of changes in the water 
itself." 



THE ELEMENTS AXD LIFE 31)5 

And again : 

As water is altogether peculiar in its activity as a solvent, and 
is a solvent which gives rise to conducting solutions, an explanation 
of its efficiency must be souglit in its own special and peculiar 
properties." 

Here again we find that the most common and familiar of 
the objects around us, and wdiich we are accustomed t<t l<M.k 
upon as the most simple, may yet really be full of marvel and 
mystery. 

The strange chemical properties of water are probably the 
cause of the singular but most important fact that water reaches 
its greatest density at 4°C. (= about 7° F.) above the freez- 
ing-point. If this curious anomaly did not exist the coldest 
w^ater would ahvays be at the bottom, and would freeze there; 
and thus many lakes and rivers during a hard winter would 
become solid ice, w-hich the succeeding summer might not bo 
able to melt. Sir Henry Koscoe says: 

" If it were not for this apparently unimportant property our 
climate would be perfectly Arctic, and Europe would in all proba- 
bility be as uninhabitable as Melville Island." ^ 

The very remarkable and highly complex relations between 
the quantity of water in our oceans, seas, and lakes, and the 
earth's habitability^ have been fully discussed in chapters xii. 
and xiii. of my volume on Man's Place in the Tni verse. 1 
will only mention here, that in those chapters I liave pointed 
out the probable origin of the great oceanic basins; the pro<ifs 
of their permanence throughout all geological tinu^; the prob- 
able causes of that pennanence; the necessity of such perma- 
nence to preserve the continuity of life-dcvel<ipment. not only 
on the earth as a whole, but on each of the izvont continents; 
and, lastly, how^ all these phenomena have cond)ined to secure 
that general uniformity of climatic conditions throughout the 
whole period of the existence of terrestrial life which was essen- 

1 Elementary Chemistry, p. 38. 



396 THE WORLD OF LIFE 

tial to its full and continuous development. There is, I be- 
lieve, no more curious and important series of phenomena con- 
nected with the possibilities of life upon the earth than those 
described in the chapters above referred to. 

Water as Preparing the Earth for Man 

There remain vet some further relations of water to life 
which may be here briefly noticed. Among the various agen- 
cies that have modelled and remodelled the earth's surface, 
water has played the most important part. It is to water that 
we owe its infinite variety, its grandeur, its picturesqueness, its 
adaptability to a highly varied vegetable and animal life; and 
this v/ork has been carried out through its manifold physical 
and chemical properties. It is in its three states, solid, liquid, 
and gaseous, that water exerts its most continuous and effective 
powers; and it is enabled to do this because, though each of 
these has its own limited range of temperature, they yet over- 
lap, as it w^ere, and can therefore act in unison. Thus within 
the narrow limits of temperature adapted to organic life we 
have both ice and water-vapour as well as liquid water, in 
almost continuous action. Through dew, mist, and rain, water 
penetrates every fissure of the rocks ; through the carbonic acid 
gas dissolved in it, the rocks are slowly decomposed ; by the 
expansion of water between 39° and 32° F. it freezes in the 
upper parts of the fissures, and when the temperature continues 
to fall the further expansion during ice-crystallisation forces 
the rocks asunder. The most massive rocks at high altitudes 
are first cracked and fissured by expansion and contraction due 
to alternations of temperature caused by sun-heat, then decom- 
posed by rain, then fractured by the irresistible force of ice- 
formation. On a large scale in polar regions, and everywhere 
at great altitudes, snowfields and permanent glaciers are 
formed, which not only carry down enormous quantities of 
debris on their surfaces or embedded in their substance, but 
with the help of that which is carried along the valley-floors 
they rest on, and by the enormous weight of the ice itself often 



THE ELEMENTS ASD LIFE :]07 

miles in thickness, grind out deep valleys and lake-l)n,sins be- 
fore cosmic or other agencies cause them to melt away. 

This continuous water-action goes on perpetually in every 
continent, and is the great agent in producing that inlinite 
variety of contour of the land surface — level plains, gentle 
slopes, beautifully rounded downs, wave-like undulations, val- 
leys in every possible variety, basin-shaped, trough-shaped, 
bounded by smooth slopes or rugged precipices, straight or 
winding, and often leading us up into the very heart of grand 
mountain scenery, with their domes and ridges and rocky peaks, 
their swift-flowing streams, rushing torrents, dark ravines, and 
glorious cascades, in endless variety, beauty, and grandeur. 

And all this we owe to what are termed the "' properties 
of water," that extremely simple and unappreciated element, 
which still abounds in mysteries that puzzle the men of science. 
Without water in all its various forms and with its many useful 
but very familiar properties, not only would life on the earth 
be impossible, but unless it had existed in the vast profusion 
of our ocean depths, and been endowed with its less familiar 
powers and forces, the whole world, instead of being a con- 
stantly varvinff scene of beauty — a verv" e:arden of delights 
for the delectation of all the higher faculties of man, — would 
have been for the most part a scene of horror, perhaps the 
sport of volcanic agencies of disruption and upheaval only 
modified by the disintegrating effects of sun and wind-action. 

Our earth mi2:ht thus have been in a state not verv dissimilar 
from that in which the moon appears to be ; not perhajis with- 
out a considerable amount of life, but with little of its variety, 
and with hardly any of that exquisite charm of contour and veg- 
etation which we are now only beginning to appreciate and 
to enjoy. 



CHAPTEK XIX 

IS NATURE CRUEL ? THE PURPOSE AND LIMITATIONS OF PAIN 

A VERY large number of persons of many shades of opinion 
and various degrees of knowledge are disturbed by the con- 
templation of the vast destruction of life ever going on in the 
world. This disturbance has become greater, has become a 
mystery, almost a nightmare of horror, since organic evolution 
through the survival of the fittest has been accepted as a law 
of nature. The working out of the details of the Darwinian 
theory has forced public attention to this destruction, to its 
universality, to its vast amount, to its being the essential means 
of progress, to its very necessity as affording the materials for 
that constant adaptation to changes in the environment which 
has been essential for the development of the whole organic 
world. 

The knowledge of this startling fact has come to us at a 
time W'hen there is a great deal of humanity in the world, when 
to vast numbers of persons every kind of cruelty is abhorrent, 
bloodshed of every kind is repugnant, and deliberate killing 
of a fellow-man the greatest of all crimes. The idea, there- 
fore, that the whole system of nature from the remotest eons 
of the past — from the very first appearance of life upon the 
earth — has been founded upon destruction of life, on the daily 
and hourly slaughter of myriads of innocent and often beau- 
tiful living things, in order to support the lives of other crea- 
tures, which others are specially adapted to destroy them, and 
are endowed w^ith all kinds of w^eapons in order that they may 
the more certainly capture and devour their victims, — all this 
is so utterly abhorrent to us that w-e cannot reconcile it with 
an author of the universe who is at once all-wise, all-powerful, 
and all-good. The consideration of these facts has been a mys- 

398 



IS XATURE CKUEL? 399 

tery to the religious, and has undoubtedly aided in the produc- 
tion of that widesj^read pessimism which exists to-day; whiK- 
it has confirmed the materialist, and great numbers of students 
of science, in the rejection of any supreme intelligence as hav- 
ing created or designed a universe which, iK'ing founded on 
cruelty and destruction, they believe to be innnoral. 

I am not aware that Darwin dealt with this question at all, 
except in the concluding words of his Origin of Species, where 
he says: 

" Thus, from the war of nature, from famine and death, the 
most exalted object we are capable of conceiving, namely, the pro- 
duction of the higher animals, directly follows." 

This admits the facts as generally conceived; and, without 
palliating them, sets on the other side the great compensating 
result. 

Much more to the point is the concluding sentence of his 
chapter on the Struggle for Existence : 

" When we reflect on this struggle, we may console ourselves 
with the full belief, that the war of nature is not incessant, that no 
fear is felt, that death is generally prompt, and that the vigorous, 
the health}^, and the happy survive and multiply." 

These statements are, I believe, strictly true, but they do not 
comprise all that can be said on the question. Before dealing 
w^ith the whole subject from the standpoint of evolution, 1 will 
quote the opinions of tw^o eminent biologists, as showing how 
the matter has impressed even thoughtful and instructed 
writers. Professor J. Arthur Thomson (of Aberdeen Tni- 
versity), wdien reviewing my Darwinism in The Theological 
Eeview, said: 

"Tone it down as you will, the fact remains that "Darwinism 
regards animals as going upstairs, in a strugirle for individual ends, 
often on tlie corpses of their fellows, often Ity a hlood-and-iron com- 
petitinn, often by a strange mixture of blood and cunning, in which 
eacli looks out for liimsolf and extinction besots the hindmost. We 



400 THE WORLD OF LIFE 

are not interested in any philosophical justification of this natural 
or unnatural method until we are sure that it is a fact." 

These words do not, I hope, represent the Professor's view 
to-day ; and I believe I shall be able to show that they by no 
means give an accurate impression of what the facts really 
are. About the same period the late Professor Huxley used 
terms still more erroneous and misleading. He spoke of the 
myriads of generations of herbivorous animals which '' have 
been tormented and devotired by carnivores " ; of the carnivores 
and herbivores alike as being " subject to all the miseries inci- 
dental to old age, disease, and over-multiplication " ; and of 
the " more or less enduring suffering '' which is " the meed of 
both vanquished and victor " ; and he concludes that, since thou- 
sands of times a minute, were our ears shai'p enough, we should 
hear sighs and groans of pain like those heard by Dante at 
the gate of Hell, the world cannot be governed by w^hat we 
call benevolence.-^ Such a strong opinion, from such an author- 
ity, must have influenced thousands of readers ; but I shall be 
able to show that these statements are not supported by facts, 
and that they are, moreover, not in accordance wdth the prin- 
ciples of that Darwinian evolution of which Huxley was so 
able and staunch a defender. 

It is the influence of such statements as these, repeated and 
even exaggerated in newspaper articles and reviews all over 
the country, that has led so many persons to fall back upon the 
teaching of Haeckel — that the universe had no designer or 
creator, but has always existed ; and that the life-pageant, with 
all its pain and horror, has been repeated cycle after cycle from 
eternity in the past, and will be repeated in similar cycles for 
ever. We have here presented to us one of the strangest 
phenomena of the human mind — that numbers of intelligent 
men are more attracted by a belief which makes the amount 
of pain which they think does exist on the earth last for all 
eternity in successive worlds without any permanent and good 

iThe Nineteenth Century, February 1888, pp. 162-163. 



IS NATURE CRUEL? 401 

result whatever, than by another belief, wliich admits the suiiio 
amount of pain into one earth only, and for a limitod period, 
while whatever pain there is only exists for the grand ])iirpose 
of developing a race of spiritual beings, who may thereafter 
live without physical pain — also for all eternity I Tu put it 
shortly — they prefer the conception of a universe in which 
pain exists perpetually and uselessly, to one in whieli the pain 
is strictly limited, while its beneficial results are eternal! 

Xone of these writers, however, nor, so far as T know, anv 
evolutionist, has ever gone to the root of the problem, by con- 
sidering the very existence of pain as being one of the essential 
factors in evolution; as having been developed in the animal 
world for a purpose ; as being strictly subordinated to the law 
of utility ; and therefore never developed beyond what was 
strictly needed for the preservation of life. It is from this 
point of view that I shall now discuss the question, and it will 
be found that it leads us to some very important conclusions. 
In order to do this, we must consider what were the conditions 
of the problem when life first appeared upon the earth. 

The general facts as to the rate of increase of animals and 
plants have been given in Chapter VII. of this work ; but even 
these facts, remarkable as they are, seem altogether insignifi- 
cant when compared with those of the lowest fonns of life. 
The most startling calculation of the kind I have seen was given 
last year in a Royal Institution lecture on The Physical Basis 
of Life, by W. B. Hardy, F.R.S. (a Cambridge tutor), as to 
one of the infusoria (Paramecium) much used for experiment 
and observation on account of its comparatively large size 
(about T^ijth inch long) and its being veiw easily procured. 
This species multiplies by division about twice in three days, and 
has been kept under observation thus multiplying for more 
than 100 generations. ]N'ow it is not very difiieult to calcnlato 
what quantity of Paramecia would be produced in any given 
number of generations, and what space they would occupy. 
Xo non-mathematical person can imagine or will Wieve the 
result. It is, that if the conditions were such (ns regards 



40^ THE WORLD OF LIFE 

space, food, etc.) that the Paramecivim could go on increasing 
for 350 generations, that is to say, for about two years, the 
produce would he sufficient in bulk to occupy a sphere larger 
than the known universe! 

I^ow taking this as a type of the Protozoa — the one-celled 
animals and plants that still exist in thousands of varied forms 
— we see in imagination the beginnings of the vast world of 
life ; and we also see the absolute necessity — if it was to con- 
tinue and develop as it has done, filling the earth with infinite 
variety, and beauty, and the joy of life — for higher and 
higher forms to come successively into being, and for these 
forms to exist upon the food provided by the bodies of the 
lower. It follows that almost simultaneously with the first 
plant-cells which had the power of extracting carbon from the 
carbonic acid gas in the air and water and converting it into 
protoplasm, the first animal cells must also have arisen; and 
both must very rapidly have diverged into varied forms in 
order to avoid the whole of the water from being monopolised 
by some one form of each, and thus checking, if not altogether 
preventing, the development of higher and more varied forms. 
Variation and selection were thus necessary from the very first 
— ^ were even far more necessary than at any later period, in 
order to avoid the possibility of the whole available space being 
occupied by some very low form to the exclusion of all others. 
Some writers have thought that, owing to the very uniform 
conditions in the primeval ocean, the development of new forms 
of life would then proceed more slowly than now. But a con- 
sideration of the enormously rapid increase of primitive life 
leads to the conclusion that the reverse was the case. It seems 
more probable that evolution proceeded as much more rapidly 
than now, as the rate of increase of the lower animals is more 
rapid than that of the highest animals. This view is supported 
by the fact, observed long ago in the Foraminifera, that their 
variability was immensely greater than in any other animals ; 
and this will serve to shorten the time required for the develop- 



IS NATURE CRUEL? 403 

ment of the life of the Cambrian period from the earliest one- 
celled animals. 

We find, then, that the whole syj^tcm of lifc-chn'elopmcnt is 
that of the lower providing food for th(^ hi^lur in ever-expand- 
ing circles of organic existence. That system has succeeded 
marvelh)usly, even gloriously, inasmuch as it has produced, as 
its final outcome, Max, the one being who can ai)preciate the 
infinite variety and beauty of the life-world, the one being who 
can utilise in any adequate manner the myriad products of its 
mechanics and its chemistry. Now, whatever view we may 
take of the universe of matter, of life, and of mind, this suc- 
cessful outcome is a proof that it is the only i)racticable metlnjd, 
the only method that could succeed. Uor if we assume (with 
the monists) that it has been throughout the outcome of the 
blind forces of nature — of '^ the rush of atoms and the clash 
of w^orlds " — then, as they themselves admit, being the out- 
come of a past eternity of trial and error, it could not have 
been otherwise. If, on the other hand, it is, as 1 urge, the 
foreordained method of a supreme mind, then it must with 
equal certainty be the hest, and almost certainly the onJn 
method, that could have subsisted through the immeasurable 
ages and could have then produced a being capable, in some 
degree, of comprehending and appreciating it. For that is 
surely the glory and distinction of man — that he is continually 
and steadily advancing in the Txnowledge of the vastness and 
mvstery of the universe in which he lives: and how anv stu- 
dent of any part of that universe can declare, as so numy do, 
that there is only a difference of degree between himself and 
the rest of the animal-world, — that, in Tlaeckel's forcible 
words, '" Our own human nature sinks to the level of a ]dacental 
mammal, which has no more value for tlie universe at large 
than the ant, the fly of a summer's day, the microscopic infu- 
sorium, or the smallest baeillu>^." — i< altoo;other beyond mv 
comprehension.^ 

1 See The Riddle of the Universe, chap. xiii. (p. 87, col. 1). 



404 THE WORLD OF LIFE 

The Evolution of Pain 

Taking it then as certain that the whole world-process is as 
it is, because it is the only method that could have succeeded, 
or that if there were alternative methods this was the best, let 
us ascertain what cojiclusions necessarily follow from it. And, 
first, we see that the whole cosmic process is based upon funda- 
mental existences, properties, and forces, the visible results of 
which we term the '' laws of nature,'' and that, in the organic 
world at all events, these laws bring about continuous develop- 
ment, on the whole progressive. One of the subsidiary results 
of this mode of development is, that no organ, no sensation, no 
faculty arises before it is needed, or in a greater degree than 
it is needed. This is the essence of Darwinism. Hence we 
may be sure that all the earlier forms of life possessed the 
minimum of sensation required for the purposes of their short 
existence ; that anything approaching to what we term '' pain " 
was imknown to them. Thev had certain functions to fulfil 
which they carried out almost automatically, though there was 
no doubt a difference of sensation just enough to cause them to 
act in one way rather than another. And as the whole purpose 
of their existence and rapid increase was that they should pro- 
vide food for other somewhat higher forms — in fact, to be 
eaten — there was no reason whatever whv that kind of death 
should have been painful to them. They could not avoid it, 
and were not intended to avoid it. It may even have been not 
only absolutely painless but slightly pleasurable — a sensation 
of warmth, a quiet loss of the little consciousness they had, 
and nothing more — " a sleep and a forgetting." 

People will not keep always in mind that pain exists in the 
world for a purpose, and a most beneficent purpose — that of 
aiding in the preservation of a sufficiency of the higher and 
more perfectly organised forms, till they have reproduced their 
hind. This being the case, it is almost as certain as anything 
not personally known can be, that all animals which breed very 
rapidly, which exist in vast numbers, and which are necessarily 



IS NATURE CRUEL? 405 

kept down to their average population by the agency of those 
that feed upon them, have little sensitiveness, perhaps only a 
slight discomfort under the most severe injuries, and that they 
probably suffer nothing at all when being devoured. For why 
should they ? They exist to be dt.'voured ; their enormous pow- 
ers of increase are for this end; they are subject to no danger- 
ous bodily injury until the time comes to be devoured, and 
therefore they need no guarding against it through the agency 
of pain. In this category, of painless, or almost painless ani- 
mals, I think we may place almost all aquatic animals up to 
fishes, all the vast hordes of insects, probably all IMollusca and 
worms; thus reducing the sphere of pain to a minimum 
throughout all the earlier geological ages, and very largely even 
now. 

When we see the sharp rows of teeth in the earlier binU 
and flying reptiles, we immediately think of the pain suffered 
by their prey ; but the teeth were in all probability necessary 
for seizing the smooth-scaled fishes or smaller land-reptiles, 
which were swallowed a moment afterw^ards ; and as no useful 
purpose would be served by the devoured suffering pain in the 
process, there is no reason to believe that they did so suffer. 
The same reasoning will apply to most of the smaller birds 
and mammals. These are all so wonderfullv adjusted to their 
environments, that, in a state of nature, they can hardly suffer 
at all from what we teinn accidents. Birds, mice, squiiTcls, 
and the like, do not get limbs broken by falls, as we do. They 
leani so quickly and certainly not to go beyond their powers 
in climbing, jumping, or flying, that they are probahly never 
injured except by rare natural causes, such a^^ lightning, hail, 
forest-fires, etc., or by fichtino- amono' themselves; and those 
who are injured without being killed by thc-^e various causes 
form such a minute fraction of the whole as to be reasonably 
negligible. The wounds received in fighting seem to be rarely 
serious, and the rapiditv with whidi <uch wonn<ls h(>al in a 
state of nature shows that whatever pain exists is not long- 
continued. 



406 THE WOKLD OF LIFE 

It is only the large, heavy, slow-moving mammals which can 
be subject to much accidental injury in a state of nature from 
such causes as rock-falls, avalanches, volcanic eruptions, or 
falling trees ; and in these cases by far the larger portion would 
either escape unhurt or would be killed outright, so that the 
amount of pain suffered would, in any circumstances, be small ; 
and as pain has been developed for the necessary purpose of 
safe-guarding the body from often-recurring dangers, not from 
those of rare occurrence, it need not be very acute. Perhaps 
self-mutilation, or fighting to the death, are the greatest dan- 
gers which most wild animals have to be guarded against ; and 
no very extreme amount of pain would be needed for this pur- 
pose, and therefore w^ould not have been produced. 

But it is undoubtedly not these lesser evils that have led to 
the outcry against the cruelty of nature, but almost wholly 
what is held to be the widespread existence of elaborate con- 
trivances for shedding blood or causing j^ain that are seen 
throughout nature — the vicious-looking teeth and claws of the 
cat-tribe, the hooked beak and prehensile talons of birds of 
prey, the poison fangs of serpents, the stings of wasps, and 
many others. The idea that all these w^eapons exist for the 
purpose of shedding blood or giving pain is wholly illusory. 
As a matter of fact, their effect is whollv beneficent even to 
the sufferers, inasmuch as they tend to the diminution of pain. 
Their actual purpose is always to prevent the escape of cap- 
tured food — of a w^ounded animal, which would then, indeed, 
suffer useless pain, since it would certainly very soon be cap- 
tured again and be devoured. The canine teeth and retractile 
claws hold the prey securely ; the serpent's fangs paralyse it ; 
and the w^asp's sting benumbs the living food stored up for its 
young, or serves as a protection against being devoured itself 
by insect-eating birds ; which latter, probably, only feel enough 
pain to warn them against such food in future. The evidence 
that animals which are devoured by lion or puma, by wolf or 
wdld cat, suffer very little, is, I think, conclusive. The sud- 
denness and violence of the seizure, the blow of the paw, the 



IS XATUKE CiWELi 407 

simultaneous deep wounds by teeth and claws, either cause 
death at once, or so paralyse the nervous system that no pain 
is felt till death very rapidly follows. It must be remembered 
that in a state of nature the Carnivora hunt and kill to satisfy 
hunger, not for amusement; and all conclusions derived from 
the house-fed cat and mouse are fallacious. Even in the case 
of man, with his highly sensitive nervous system, which has 
been developed on account of his unprotected skin and excessive 
liability to accidental injury, seizure by a lion or tiger is hardly 
painful or mentally distressing, as testified by those who have 
been thus seized and have escaped.^ 

Our whole tendency to transfer our sensations of pain to all 
other animals is grossly misleading. The probability is, that 
there is as great a gap between man and the lower animals in 
sensitiveness to pain as there is in their intellectual and moral 
faculties; and as a concomitant of those higher faculties. We 
require to be more sensitive to pain because of our bare skin 
with no protective armour or thick pads of hair to ward off 
blows, or to guard against scratches and wounds from the many 
spiny or prickly plants that abound in every part of the world ; 
and especially on account of our long infancy and childhood. 
And here I think I see the solution of a problem which has 
long puzzled me — wJiy man lost his hairy covering, especially 
from his back, where it would be so useful in carrying off 
rain. He inaij have lost it, gradually, from the time when he 
first became Man — the spiritual being, the 'Miving soul" in 
a corporeal body, in order to render him 7nore se7isitivc. From 
that moment he was destined to the intellectual advance which 
we term civilisation. He was to be exposed to a thousand self- 
created dangers totally unknown to the rest of the animal world. 
His very earliest advance towards civilisation — the use of fire 
— became thenceforth a daily and liourlv danger to him, to be 
guarded against only by sudden and acute pain ; and as he 
advanced onwards and his life became more complex; as he 
surrounded himself with dwellings, and made clothing and 

1 See a brief discussion «>f tliis snl»jc<'t in my Darwinism, i>]>. :^()-40. 



408 THE WOKLD OF LIFE 

adopted cookery as a daily practice, he became more and more 
exposed to loss, to injury, and to death from fire, and thus 
would be subject to the law of selection by which those less 
sensitive to fire, and therefore more careless in the use of it, 
became eliminated. 

Ilia tools continually becoming more and more dangerous, 
and his weapons becoming more and more destructive, w^ere 
alike a danger to him. The scythe and the sickle caused acci- 
dental woimds, as did the needle and the knife. The club and 
the axe, the spear and the arrow, the sword and the dagger, 
caused wounds which, if not avoided, led quickly to death. 
Hence beneficent pain increased with him as a warning of dan- 
ger, impelling him to the avoidance of wounds by skill and 
dexterity, by the use of padded clothing or of flexible armour; 
w^hile nature's remedies were sought out to heal the less deadly 
injuries, and thus avoid long suffering or permanent disable- 
ment. And ever as civilisation went on, such dangers in- 
creased. Explosives caused a new kind of wound from musket 
or pistol, and later from bombs and mines. Boats and ships 
were built and the ocean traversed. Endless forms of machin- 
ery were invented, at first hand-worked, and not dangerous to 
the worker, but soon driven by steam with such force that if 
carelessly entangled in it the worker's limbs might be torn from 
his body. And all this went on increasing till at last a large 
proportion of the human race laboured daily in peril of life 
or limb, or of painful wounds, or worse diseases. Against this 
vast ever-present network of dangers, together with the ever- 
present danger of consuming fire, man is warned and protected 
by an ever-increasing sensibility to pain, a horror at the very 
sight of wounds and blood ; and it is this specially developed sen- 
sibility that we, most illogically, transfer to the animal-world 
in our wholly exaggerated and often quite mistaken views as to 
the crueltv of nature! 

As a proof of the increased sensibility of the civilised as 
compared with the more savage races, we have the well-known 



IS NATURE CRUEL ^ 409 

facts of the natives of many parts of the world enduring what 
to us would be dreadful torments without exhibiting any signs 
of pain. Examples of this are to be found in almost every 
book of travels. I will here only mention one. Among most 
of the Australian tribes there is a regular scale of punishment 
for various offences. When a man entices awav another man's 
wife (or in some other offence of an allied nature) the allotted 
punishment is, that the complainant and his nearest relatives, 
often eight or ten in number or even more, are to be allowed 
to thrust a spear of a certain size into the offender's leg between 
ankle and knee. The criminal appears before the chiefs of the 
tribe, he holds out his leg, and one after another the members 
of the offended family walk up in turn, each sticks in his 
spear, draws it out, and retires. When all have done so, the 
leg is a mass of torn flesh and skin and blood ; the sufferer has 
stood still without shrinking during the whole operation. Tie 
then goes to his hut with his wife, lies down, and she covers 
the leg with dust — probably fine wood ashes. For a few 
days he is fed with a thin gruel only, then gets up, and is very 
soon as well as ever, except for a badly scarred leg. Of course 
we cannot tell what he actually suffered, but certainly the aver- 
age European could not have endured such pain unmoved. 

This, however, is only an illustration. It is not essential 
to the argument, which is founded wholly on the principles 
of Darwinian evolution. One of these principles, much in- 
sisted on by Darwin, is, that no organ, faculty, or sensation 
can have arisen in animals except through its utility to the 
species. The sensation of pain has been thus developed, and 
must therefore be proportionate in each species to its needs, 
not heyond those needs. In the lowest animals, whose numbers 
are enormous, whose powers of increase are excessive, whose 
individual lives are measured bv hours or davs, and which 
exist to be devoured, pain would bo almost or quite useless, and 
would therefore not exist. Only as the organism increased in 
complexity, in duratiou of life, nnrl in exposure to danger which 



no THE WORLD OF LIFE 

migtit possibly lead to its death before it could either leave 
offspring or serve as food to some higher form — only then 
could pain have any use or meaning. 

I have now endeavoured, very roughly, to follow out this 
principle to its logical results, which are, that only in the higher 
and larger members of the highest vertebrates — mammals and 
birds, do the conditions exist which render acute sensations of 
pain necessary, or even serviceable. Only in the most highly 
organised, such as dogs and horses, cattle, antelopes, and deer, 
does there appear to be any need for acute sensations of pain, 
and these are almost certainly, for reasons already given, very 
much less than ours. The logical conclusion is, therefore, that 
they only suffer a very moderate amount of pain from such 
bodily injuries as they are subject to in a state of nature. 

I have already shown that in most cases, even from our much 
higher standard, their death would be rapid and almost pain- 
less ; whence it follows, that the widespread idea of the cruelty 
of nature is almost wholly imaginary. It rests on the false 
assumption that the sensations of the lower animals are neces- 
sarily equal to our own, and takes no account whatever of these 
fundamental principles of evolution which almost all the critics 
profess to accept. 

There is, of course, a large body of facts which indicate that 
whole classes of animals, though very highly organised, suffer 
nothing which can be called pain, as in the insects ; and similar 
facts show us that even the highest warm-blooded animals suffer 
very much less than we do. But my argument here does not 
depend upon any such evidence, but on the universally accepted 
doctrine of evolution through adaptation. According to that 
theory, it is only life-preserving variations, qualities, or faculties 
that have survival value: pain is one of the most important of 
these for us, but it is by no means so important to any other 
animal, ^o other animal needs the pain-sensations that we 
need; it is therefore absolutely certain that no other possesses 
such sensations in more than a fractional degree of ours. What 



IS NATURE CRUEL? 411 

that fraction is we can only roughly estimate by carefully con- 
sidering the circumstances of each case. These show that it 
is certainly almost infinitesimal in by far the larger part of the 
animal kingdom, very small in all invertebrates, moderately 
small in fishes and reptiles, as well as in all the smaller birds 
and mammals. In the larger of these two classes it is prob- 
ably considerable, but still far below that of even the lowest 
races of man. 

A Possible Misconception 

It may be said — I fear it will be said — that this idea of 
the lower animals suffering less pain than we suffer will Ix* 
taken as an argument in favour of vivisection. Xo doubt it 
will; but that docs not in the least affect the actual truth of 
the matter, which is, I believe, as I have stated. The moral 
argument against vivisection remains, whether the animals suf- 
fer as much as we do or only half as much. The bad effect 
on the operator and on the students and spectators remains; 
the undoubted fact that the practice tends to produce a callous- 
ness and a passion for experiment, which leads to unauthorised 
experiments in hospitals on unprotected patients, remains; the 
horrible callousness of binding the sufferers in the operating 
trough, so that they cannot express their pain by sound or 
motion, remains; their treatment, after the experiment, by 
careless attendants, brutalised by custom, remains ; the argu- 
ment of the uselessness of a large proportion of the experi- 
ments, repeated again and again on scores and hundreds of 
animals, to confirm or refute the work of other vivisectors, 
remains ; and, finally, the iniquity of its use to demonstrate 
already-established facts to physiological students in hundreds 
of colleges and schools all over the world, remains. T myself 
am thankful to be able to believe that even the hiijhest animals 
below ourselves do not feel so acutely as we do; but that fact 
does not in anv wav remove mv fundamental disgust at vivi- 
section as being brutalising and immoral. 



412 THE WORLD OY LIFE 

A Recent Illustration of the Necessity of Pain 

Within the last few years we have had remarkable proofs 
of the beneficence of pain as a life-saver by the sad results of 
its absence. The recently discovered X-rays, so much used 
now for localising internal injuries, and of bullets or other 
foreign objects in any part of the body, have the property also 
of setting up a special internal disorganisation unaccompanied 
at the time by pain. The result has been loss of limbs or loss of 
life to some of the earlier investigators, and perhaps some in- 
jury even to the patients for whose benefit it has been applied. 
It seems probable, therefore, that if these rays had been asso- 
ciated in any perceptible degTce with the heat and light we re- 
ceive from the sun, either the course of evolution would have 
been very different from what it has been, or the development of 
life have been rendered impossible. Pain has not accompanied 
the incidence of these rays on the body, because living organ- 
isms have never hitherto been exposed to their injurious effects. 

Microbes and Parasites: their Purpose in the Life-World 

Much light is thrown on the analogous problem of those 
human diseases which are supposed to be caused by germs, 
microbes, or 2:)arasites, by the application of the more extended 
views of evolution I have advocated in the present volume. 
The medical profession aj^pear to hold the view that pathogenic 
or disease-producing microbes exist for the purpose of causing 
disease in otherwise healthy bodies to which they gain access 
— that they are, in fact, wholly evil. It is also claimed that 
the only safeguard against them is some kind of ^' anti-toxin " 
with which everv one must be inoculated to be saved from the 
danger of attack by some or all of the large number of such 
diseases which affect almost every organ and function of the 
body. This view seems to me to be fundamentally wrong, be- 
cause it does not show us any use for such microbes in the 
scheme of life, and also because it does not recognise that a 
condition nf health is the one and only protection we require 



IS NATURE CRUEL? 413 

against all kinds of disease; and that to put any product of 
disease whatever into the blood of a really healthy person is to 
create a danger far greater than the disease itself. 

On the general principles of the present argunienr there 
can be nothing in nature which is not useful, and, in a broad 
sense, essential to the whole scheme of the life-wtudd. (Jn this 
principle the purpose and use of all parasitic diseases, including 
those caused by pathogenic germs, i?^ to seize upon the less 
adapted and less healthy individuals — those which are slowly 
dying and no longer of value in the preservation of the species, 
and therefore to a certain extent injurious to the race by recpiir- 
ing food and occupying space needed by the more fit. Tlicir 
life is thus shortened, and a lingering and unenjoyable exist- 
ence more speedily terminated. One recent writer seems to hold 
this view, as shown by the following passage: 

" Before it was perceived that disease is an undisputable battle- 
field of the true Darwinian struggle for existence, the tremendous 
part which it takes in ridding the earth of weaklings and causing 
the survival of health, was all credited to the environment and its 
dead physical forces." ^ 

Bnt in this interesting article the writer elsewhere uses lan- 
guage implying that even the healthy require rendering '' im- 
mune " against all zymotic diseases. It is tliat idea which I 
protest against as a libel on nature and on the Ruler of the 
Universe; and in its practice as constituting a crime of equal 
gravity Avith vivisection itself. 

It will be said that quite healthy persons die (^f thesi^ dis- 
eases, but that cannot be proved; and the absolutely universal 
fact that it is among those living under unhealthy conditions 
in our towns, and cities, and villages, that suft'er most from these 
diseases is strongly against the truth of the statement. No 
doubt savage races often suffer drearlfully from these diseases; 
but savages are no more universally healthy than the more civil- 

1 Parasitism and Natural Sclrotioii. l)y R. O. Eccles, M.D., Brooklyn, N. 
Y., U. S. A. 



414 THE WOELD OE LIFE 

ised, though it is usually a different kind of unhealthiness. 
The only doctrine on this matter worthy of an evolutionist, or 
of a believer in God, is that health of body and of mind are 
the only natural safeguards against disease; and that securing 
the conditions for such health for every individual is the one 
and only test of a true civilisation. 

A few words in conclusion on the main question of pain in 
the animal world. In my treatment of the subject I believe I 
have given imnecessary weight to those appearances by which 
alone we judge of pain in the lower animals. I feel sure that 
those appearances are often deceptive, and that the only true 
guide to the evolutionist is a full and careful consideration of 
the amount of necessity there exists in each group for pain- 
sensation to have been developed in order to preserve the young 
from common dangers to life and limb before they have reached 
full maturity. It is exactly the same argument as I have made 
use of in discussing the question of how mxuch colour-sense can 
have been developed in mammals or in butterflies. In both 
cases it depends fundamentally on utilities of life-saving value 
as required for the continuance of the race. Hitherto the prob- 
lem has never been considered from this point of view, the only 
one for the evolutionist to adopt. Hence the ludicrously exag- 
gerated view adopted by men of such eminence and usually 
of such calm judgment as Huxley — a view almost as far re- 
moved from fact or science as the purely imaginary and 
humanitarian dogma of the poet: 

The poor beetle, that we tread upon, 

In corporal sufferance feels a pang as great 

As when a giant dies. 

Whatever the giant may feel, if the theory of evolution is 
true, the '' poor beetle " certainly feels an almost irreducible 
minimum of pain, probably none at all. 



CHAPTER XX 

INFINITE VARIETY THE LAW OF THE UNIVERSE CONCLUSION 

Throughout the present work I have liad occasion to call 
attention to the endless diversity that characterises both organic 
and inorganic nature. In a previous work, Man's Place in the 
Universe, I was impressed by the diversity which the new 
astronomy had shown to exist throughout the stellar universe. 
Since that book was written such remarkable advance has been 
made in relation to the nature of matter itself, as to constitute 
almost a new science. It seems desirable, therefore, to say a 
few words here upon the whole question of the variety and 
complexity of every part of the material universe in its rela- 
tion to man as an intellectual and moral l:)eing, thus summaris- 
ing the whole aim and tendency of the present work. 

It will, I think, be most instructive to follow the same order 
as I have adopted in the present volume, of showing how each 
kind of variety and complexity that presents itself to us can 
be traced back as dependent upon a preceding complexity, 
usually less obvious and more recently brought to light. Thus, 
the most obvious of all the diversities in nature is that of the 
various forms (or kinds) of animals and plants ; whereas the 
diversities of inorganic nature — stones, rocks, etc., are far less 
obvious, and were discovered at a much later period. 

The Causes of the Diversity of Life-forms 

Modern research shows us that the immense diversitv of life- 
forms we now find upon the earth is due to two kinds of causes, 
the one immediate, the other remote. The iuimediate cause 
is (as I have endeavoured to show here), the slow but continu- 
ous changes of the earth's surface ns regards contour, altitude, 
climate, and distribution of land and water, which successively 

415 



416 THE WORLD OF LIFE 

open new and unoccupied places in nature, to fill which some 
previously existing forms become adapted through variation 
and natural selection. I have sufficiently shown how this proc- 
ess has worked throughout the geological ages, the world's sur- 
face ever becoming more complex through the action of the 
lowering and elevating causes on a crust which at each succes- 
sive epoch has itself become more complex. This has always 
resulted in a more varied and generally higher type of vegeta- 
tion, and through this a more varied and higher type of animal 
life. 

The remote but more fundamental cause, which has been 
comparatively little attended to, is the existence of a special 
group of elements possessing such exceptional and altogether 
extraordinary properties as to render possible the existence of 
vegetable and animal life-forms. These elements correspond 
roughly to the fuel, the iron, and the water which render a 
steam-engine possible; but the powers, the complexities, and 
the results are millions of times greater in the former, and we 
may presume that the Mind which first caused these elements 
to exist, and then built them up into such man^ellous living, 
moving, self-supporting, and self-reproducing structures, must 
be many millions times greater than those which conceived and 
executed the modem steam-engine. 

Variety of Inorganic Substances 

The recognised elements are now about eighty in number, 
and half of these have been discovered during the past century ; 
while twenty of them, or one-fourth of the whole, have been 
added during the last fifty years. These last are all very rare, 
but among those discovered in the preceding fifty years are 
such now familiar and important elements as aluminium, 
bromine, silicon, iodine, fluorine, and chlorine. So far as the 
elements are concerned, our earth has doubled in apparent com- 
plexity of structure during the last century. But if we take 
account of the advance of chemical science, the knowledge that 
has been obtained of the inner nature of the best-known older 



THE PURPOSE OF DIVEHSITY 417 

elements, the wonderfully c'()ini)lr'x laws of tlioir combinations, 
and the immense variety of their known eompounds, our ever- 
increasing knowledge of the complexity of matter will he vory 
much greater. 

During the early part of the nineteenth century, tlie old 
idea of atoms as being indivisible, incompressible, and inde- 
structible particles, almost universally prevailed. They were 
usually supposed to be spherical in form, and 1<> 1m^ the scat 
of both attractive and repulsive forces, leading to cohesion and 
chemical combination. Those of the different elements were 
supposed to differ slightly in size, and energy, which led to 
their differences of weight and other properties. The whole 
conception, though we now see it to be totally inadequate, was 
comparatively simple, and with the help of the mysterious elec- 
tric and magnetic forces seemed capable of explaining much. 

But, decade after decade, fresh discoveries were made ; chem- 
ical theory became more and more complex; electricity, the 
more it was known the less intelligible it became ; while a host 
of new discoveries in the radiant forces of the ether seemed to 
show that this mysterious substance was really the seat of all 
the forces of the universe, and that the various basic forms of 
matter which we term elements were nothing more than the 
special manifestation of those forces. It thus became evident 
that all our progress in physical science rendered the world of 
matter far more wonderful, and at the same time less intel- 
ligible than it had ever seemed to us before.^ 

1 The progress of modern chemistry well shows this increasing com- 
plexity with increasing knowledge. The fact of carbon existing in three 
distinct forms — charcoal, graphite, and diamond, each with its own special 
physical and chemical characters — has already been referred to. Hut it 
is found that many other elements have similar properties, especially sili- 
con, phosphorus, arsenic, antimony, sulphur, oxygen, and several others. 
This curious property is termed allotropy; and it seems somewhat analo- 
gous to that property of many compound substances termed isomerism, of 
which two striking examples were given at tlie beginning of the last 
chapter. Another modern braneh of chemistry is the stuily of the relation 
of crystallised substances to polarised light, which reveals nuiny new and 
strange properties of identical compounds, and is termed iStcrcochcmistry. 



418 THE WORLD OF LIFE 

Eetuming now to the different forms under which matter 
exists in that portion of the earth which we can examine, we 
find them to be very limited as compared with those of the 
organic world. The crust of the earth, and presumably the 
interior also, consists mainly of what are called minerals, which 
is the term used for all chemical compounds of the elements 
which have been produced under natural laws and forces, and 
constitute the materials of the whole planet. They comprise, 
besides the elements themselves, the various salts, alkalis, earths, 
metallic ores, precious stones, and crystals, which have a def- 
inite chemical constitution, a permanent form, and definite 
characters ; forming what are termed mineral species. These, 
when disintegrated by natural forces, intermingled in various 
ways, and solidified in various degrees, make up the whole mass 
of rocks and surface material of the earth. The total number 
of mineral-species now known, almost the whole of which are 
to be found in the fine mineralogical gallery of the British 
Museum, is almost exactly a thousand. Many of these are 
very rare or local, the great bulk of the rocks being made up 
of a few score, or at most of a few hundreds of them. 

The generally accepted idea being that the whole earth was 
once a molten mass, the crust may be supposed to give a fair 
sample of the whole ; and the additional fact that, during all 
geological time, matter from the interior has been brought to 

These various properties of the atoms and molecules of matter have so 
complicated their relations, that the attempt to unravel them has led to a 
system of equations, of diagrams, and of formulae, which are almost as 
difficult for the general reader to follow in detail, as is the working out of 
some abstruse mathematical investigation. As an example of this complex- 
ity in chemical nomenclature I may refer to a recent paper by Sir William 
Crookes, on the rare metal scandium (discovered in 1879). Near the 
end of this paper (in the Proc. Roy. Soc, series A, vol. 84, p. 84), the 
author says : " By the kindness of Dr. Silberrad, I have had an oppor- 
tunity of experimenting with octamethyltetraminodihydroxyparadixunthyl- 
bezonetetracarboxilic acid." 

He then adds : " Previous experiments would lead one to expect the 
scandium salt of this acid to have the composition C44H4oOi4N4Se;. The 
only scandium salt I could form with this acid has the composition 

CssHjgOoaXsSCj. 



THE PURPOSE OF DIVEESITY 419 

the surface by volcanoes and liot springs, renders it prol>:d)lo 
that very few either of the elements or compounds remain 
unknown. 

The skill of the chemist, however, has led to the production 
of a much greater number of stable chemical compounds than 
occur in nature. These are used in medicine or in the various 
arts, and their numbers are very great. They are usually 
divided into two classes, the inorganic and the (jrganic; the 
former being of the same nature as tliose of the great bulk of 
the mineral species, while the latter, called also carbon-com- 
pounds, resemble the products of living organisms of which 
carbon is an essential part. 

A recent estimate of the known inorganic compounds, 
natural and artificial, bv a French chemist is 8000 ; but ^Ir. 
L. Fletcher, of the British [Museum, informs me that this 
number must onlv be taken as an '' irreducible minimum.'' 
As to organic compounds, I am told by Professor II. E. Arm- 
strong, that they have recently been estimated at about 100, 
000 ; but he states that the j^ossihilities of forming such com- 
pounds are infinite, that chemists can make them by thousand 
if required, and that they now limit themselves to those which 
have some special interest. The approximate figures for the 
various kinds of stable chemical compounds now known, will 
therefore form an easily remembered series : — 

Mineral species 1 ,000 

Inorganic compounds (artificial) 10,000 

Organic compounds (artificial) 100,000 

Possible organic compounds Infinite! 

What a wonderful conception this affords us of the possi- 
bilities of the elements (or rather of about one-fifth of them) 
to produce the almost endless variety of natural products in 
the vegetable and animn! kinirdoms. Tliese possibilities must 
depend upon the "properties" of the elements; not only their 
actual properties as elements, but their latent pntperties 
through which they not only combine with each other in a 
great variety of ways, but, by each eombi nation create, as it 



420 THE WOELD OP LIFE 

were, a new substance, possessing properties and powers dif- 
ferent from those of any other substances whatever. These 
almost infinitely various properties of chemical combinations, 
together with a host of other problems with which the organic 
chemist has to deal, have led some of them to almost exactly 
the same conclusion to which I have been led by a more super- 
ficial view of the marvels of '' growth " and cell-division in 
living organisms. In the Address already quoted, Sir H. E. 
Armstrong says, after referring to some of the complex and 
extraordinary chemical transformations produced by living 
plants : 

" The general impression produced by facts such as these is, 
that directive influences are the paramount influences at work in 
building up living tissues." 

And again more explicitly : 

" It would seem that control is exercised and stability secured 
in several ways; not only is the form laid down in advance but 
certain chosen materials are alone available, and the builders can 
only unite particular materials in particular ways." 

It is very satisfactory to find that both chemists and 
physiologists recognise the absolute need of some controlling 
and directive power in elaborating the special products or 
building up the complex tissues of plants and animals. 

The Cause and Purpose of this Variety 

The general conclusion to which the whole argument of 
this volume tends, is, that the infinite variety we see in nature 
can be traced back step by step to the almost infinite complexity 
of the cells by means of which they live and gi'ow; of the 
protoplasm which is the substance of the cells; of the elements 
of which protoplasm consists ; of the molecules of those 
elements ; and finally of the atoms whose combination forms 
the separate and totally distinct elementary molecules. And 
at each step farther back we are as far ofi^ as ever from com- 



THE PUliPOSE or DlVEruSITY 421 

prehending how it is possible for such infinite diversity to 
be brought about. And now that we are led to believe that 
the atom itself is highly complex — that it is a system of re- 
volving electrons or coi-puscles, held together by tremon«lous 
forces — the mystery becomes deeper still, and we find it (piite 
hopeless to realise what is the nature of the controlling power 
and mind, Avhich out of such unimaginable entities lias built 
up the vast material universe of suns and systems of which 
our earth foimis a fractional part, together w^ith that even 
more complex world of life of which we ourselves are the out- 
come. 

The overwhelming complexity and divei'sity of this vast 
cosmos in its every part and detail, is the great fundamental 
characteristic which our highest science has brought promi- 
nently to our notice ; but neither science nor religion has given 
us the slightest clue as to why it should be so. Science says : 
" It is so. Ours not to reason why ; but only to find out what 
is.'' Religion says : " God made it so " ; and sometimes adds, 
" it was God's will ; it is impious to seek any other reason." 
In the present work I have endeavoured to suggest a reason 
which appeals to me as both a sufficient and an intelligible 
one: it is that this earth with its infinitude of life and beauty 
and mystery, and the universe in the midst of which we are 
placed, with its overwhelming immensities of suns and nebuho, 
of light and motion, are as they are, firstly, for the develop- 
ment of life culminating in man ; secondly, as a vast school- 
house for the higher education of the human race in pn^jia ra- 
tion for the enduring spiritual life to which it is destined. 

I have endeavoured to show that some portion at least of 
what seems a superfluity of elements in our earth-structure 
has ser\'ed the purpose of aiding the gi'adual progress of man 
from barbarism to material civilisation ; while another portion 
has furnished him with materials which have alone enabled 
him to penetrate into the two unkninvn worlds with which ho 
was encompassed — those of the nlniost infinitely great and 
of the almost infiuitelv little; but both alike attractive an<l 



422 THE WOELD OF LIFE 

grand in their revelations; both, offering ever-fresh vistas of 
unf athomed mysteries ; both impressing upon him the existence 
of immanent forces and controlling mind-power as their only 
possible cause. 

I suggest, further, that these deeper and deeper mysteries 
which confront us everywhere as we advance farther in our 
knowledge of this universe, are now serving, and will serve 
in the future so long as man exists upon the earth, to give 
him more and more adequate conceptions of the power, and 
perhaps to some extent of the nature, of the author of that 
universe ; will furnish him with the materials for a religion 
founded on knowledge, in the place of all existing religions, 
based largely on the wholly inadequate conceptions and be- 
liefs of by-gone ages. 

ft 

A Suggestion as to the Origin of Life 

As it may be expected that I should state what is my ovm 
conception of the power which I claim to be proved to exist, 
and to be the fundamental cause of the life-world as well as 
of the material universe, I will here make a few suggestions 
as to what seems to me to be the least improbable, the least 
difficult, of all attempts to deal with what Herbert Spencer 
held to be " unknowable," but the non-existence of which he 
held to be unthinkable. In the Chapter on Religion, in Dar- 
win's Life and Letters, he also seems to have rested in the one 
conclusion, that the universe could not have existed without an 
intelligent cause, but that any adequate conception of the 
nature of that cause was beyond the powers of the human mind 
to form. With these views I am in complete sympathy; but 
I yet think that we can form some conceptions of the powers 
at work in nature which help us to overcome the insuperable 
difficulty as to the nature of the infinite and absolute creator, 
not only of our world and our universe, but of all that exists 
or can exist in infinite space. Here, as everywhere in science, 
we must not attempt to deal with the ultimate problem with- 



THE PUKP08E OF DIVEKSITY 423 

out studying or com2:)relieu(]iiig the steps hy which it may be 
approached. 

I venture to hope that in the present volume, and especially 
in the last six chapters, I have satisfied most of my rc^aders 
that the vast life-world, with its myriad forms, each one 
originating in a single cell, yet growing, by cell-division, into 
such marvels of variety, of use, and of beauty, does absolutely 
require some non-mechanical mind and power as its efficient 
cause. To such onlv mv further ar":ument will be directed. 

My first point is, that the organising mind which actually 
carries out the development of the life-world need not bo in- 
finite in any of its attributes — need not be what is usually 
meant by the terms God or Deity. The main cause of the 
antagonism between religion and science seems to me to be 
the assumption by both that there are no existences capable 
of taking part in the work of creation other than blind forces 
on the one hand, and the infinite, eternal, omnipotent God on 
the other. The apparently gratuitous creation by theologians 
of a hierarchy of angels and archangels, with no defined duties 
but that of attendants and messengers of the Deity, perhaps 
increases this antagonism, but it seems to me that both ideas 
are irrational. If, as I contend, we are forced to the assump- 
tion of an infinite God by the fact that our earth has developed 
life, and mind, and ourselves, it seems only logical to assume 
that the vast, the infinite chasm between ourselves and the 
Deity is to some extent occupied by an almost inlinite scries 
of grades of beings, each successive* grade having higher and 
higher powers in regard to the origination, the development, 
and the control of the universe. 

If, as I here suggest, the whole* purport of the material 
imiverse (our universe) is the development of spiritual beings 
who, in the infinite variety of their natures — what we term 
their characters, — shall to some extent reflect that infinite 
variety of the whole inoriranic and orijanie worlds through 
which they have been developed; and if we further suppose 



424 THE WORLD OF LIFE 

(as we must suppose if we owe our existence to Deity) that 
such variety of character could have been produced in no other 
way; then we may reasonably suppose that there may have 
been a vast system of co-operation of such grades of being, 
from a very high grade of power and intelligence down to 
those unconscious or almost unconscious ^' cell-souls " posited 
by Haeckel, and w^hich, I quite admit, seem to be essential 
coadjutors in the process of life-development. 

Xow granting all this, and granting, further, that each 
grade of being would be, for such a purpose as this, supreme 
over all beings of lower grade, who would carry out their 
orders or ideas with the most delighted and intelligent obe- 
dience; I can imagine the supreme, the Infinite being, fore- 
seeing and determining the broad outlines of a universe which 
w^ould, in due course and with efficient guidance, produce the 
required result. He might, for instance, impress a sufficient 
number of his highest angels to create by their will-power the 
2:»rimal universe of ether, with all those inherent properties and 
forces necessary for what was to follow\ Using this as a 
vehicle the next subordinate association of angels would so act 
upon the ether as to develop from it, in suitable masses and 
at suitable distances, the various elements of matter, which, 
under the influence of such laws and forces as gravitation, 
heat, and electricity, would thenceforth begin to form those 
vast systems of nebulae and suns which constitute our stellar 
universe. 

Then we may imagine these hosts of angels, to whom a 
thousand years are as one day, watching the development of 
this vast system of suns and planets until some one or more 
of them combined in itself all those conditions of size, of 
elementary constitution, of atmosphere, of mass of water and 
requisite distance from its source of heat, as to ensure a 
stability of constitution and uniformity of temperature for 
a given minimum of millions of years or of ages, as would 
be required for the full development of a life-world from 



THE PURPOSE OF DiVEiiSiTY 425 

Amoeba to Man, with a surplus of a few Inmdred millions 
for his adequate development. 

Thought-transference as an agent in Creation 

In my Man's Place in the Universe I have pointed out 
the very narrow range of the quantitative and qualitativp con- 
ditions which such a world must possess ; and tlie next stop 
in the process of what may be wtU termed " creation '' would 
be the initiation of life by the same or a subordinate body of 
spirit-workers, whose duty would be, when the waters of the 
cooling earth had reached a proper temperature and were 
sufficiently saturated with gases and carbon-compounds, to 
infuse into it suitable life-centres to begin the process of or- 
ganisation, which, as Huxley acknowledged, implies life as its 
cause. How this was done it is impossible for us to know, 
and useless to speculate; but there are certain guides. From 
Haeckel's concession of ^' cell-souls " possessing volition, but 
a minimum of sensation, we have one conceivable starting- 
point. From Weismann's vivid description of cell-growth and 
cell-division, w-ith its complex apparatus, its purposive motions 
so evidently adapted to bring about a definite result, and its 
invariable onward march to that result, we as surely imply 
an intelligence and power far beyond anything we know or can 
clearly conceive. 

We are led, therefore, to postulate a body of what wo may 
term organising spirits, who would be charged with the duty 
of so influencing the myriads of cell-souls as to carry out their 
part of the work with accuracy and certainty. In the power 
of ^' thought-transference " or mental impression, now gener- 
ally admitted to be a vera causa, possessed by many, perhaps 
by all of us, we can understand how the higher intelligences 
are able to so act upon the lower and that the work of the 
latter soon becomes automatic. The work of the organisers 
is then directed to keeping up the supply of life-material to 
enable the cell-souls to perform their duties while tlie cells are 
rapidly increasing. 



426 THE WORLD OF LIFE 

At successive stages of development of the life-world, more 
and perhaps higher intelligences might be required to direct 
the main lines of variation in definite directions in accordance 
with the general design to be w^orked out, and to guard against 
a break in the particular line which alone could lead ultimately 
to the production of the human form. Some such conception 
as this — of delegated powers to beings of a very high, and to 
others of a very low grade of life and intellect — seems to me 
less grossly improbable than that the infinite Deity not only 
designed the whole of the cosmos, but that himself alone is 
the consciously acting power in every cell of every living thing 
that is or ever has been upon the earth. 

What I should imagine the highest intelligence engaged in 
the w^ork (and this not the Infinite) to have done would be 
so to constitute the substance of our universe that it would 
afford the materials and the best conditions for the development 
of life ; and also, under the simple laws of variation, increase, 
and survival, would automatically lead to the maximum of vari- 
ety, beauty, and use for man, when the time came for his ap- 
pearance ; and that all this should take place with the minimum 
of guidance beyond that necessary for the actual working of the 
life-machinery of all the organisms that were produced under 
these laws. Some such conception seems to me to be in har- 
mony with the universal teaching of nature — everyw^here an 
almost infinite variety, not as a detailed design (as when it 
was supposed that God made every valley and mountain, every 
insect and every serpent), but as a foreseen result of the con- 
stitution of the universe. The vast whole is therefore a mani- 
festation of his powTr — perhaps of his very self — but by 
the agency of his ministering angels through many descending 
grades of intelligence and power. 

Diversify of Human Character 

Many people are disturbed by the now w-ell-established fact 
that the effects of use, of training, or of education, are not 
inherited; and that though innate mental as well as bodily 



THE PURPOSE OF DIVEPSITY 427 

characters vary mucli througli inlieritanco these can only l)e 
developed in special directions hy some form of selection. 
There being very little if any effective selection of character 
among civilised people, they therefore fear that there can he 
no continued advance of the race. Quite recently 1 have dis- 
cussed this question from two points of view. I^y a general 
glance over the early history of civilis.'d man 1 have shown 
that there is little if any evidence of advance in character «h- 
in intellect from the earliest times of which we have anv 
record.^ I had already, twenty years ago, shown in some d(»- 
tail how, under a rational system of society, in which all the 
present soul-degrading influences of individualistic wealth and 
poverty would be abolished, (especially as leading to unholy 
marriages) a progressive advance in character would neces- 
sarily arise through elimination of the worst and most degraded 
bv an effective and trulv natural selection.- The following 
passage towards the end of the former article will briefly indi- 
cate the nature of the argument in both these essays: 

" The great lesson taught us by this brief exposition of the 
phenomena of character in relation to the known laws of organic 
evolution is this: that our imperfect human nature, with its almost 
infinite possibilities of good and evil, can only make a systematic 
advance through the thoroughly sympathetic and ethical training 
of every child from infancy upwards, combined with that perfect 
freedom of choice in marriage which will only be possihle wlien all 
are economically equal, and no question of social rank or material 
advantage can have the slightest influence in determining that 
choice." 

It now only remains to show, verv brieflv, how tlu^ views 
here sketched out are in perfect harmony with the entire scheme 
of the life-world. That scheme is shown to be the production 
of an almost infinite diversity in forms of life, beautifuUv eo 
ordinated for the common good, and for the ultimate develop- 

1 " Evolution and Character," Fortnijjhtly Review. January 1. I'JOS. 
•-'"Human Selection." Fortni«ilit ly Review. Septj-niber ISOl). Reprinted 
in Studies, Scientific and Social, 1900, vol. i. p. 509. 



428 THE WORLD OF LIFE 

ment and education of an almost equally varied humanity. 
That variety has been assured and increased by the rapid de- 
velopment of man — from the epoch when he became a liv- 
ing soul conscious of good and evil — so far above the beasts 
which perish that there was little actual selection except to 
ensure health and vigour, and the gradual advance towards 
civilisation. All types of character had a fairly equal chance 
of survival and of leaving offspring, and thus the continued un- 
checked action of the universal law of variation led to an 
amount of diversity of human nature far above that of any 
of the lower animals. We see this diversity manifested through 
all the ages, from the lowest depths of a Nero, a Borgia, or 
a De Eetz, to the glorious heights of a Confucius or a Buddha, 
a Socrates or a Newton. 

But if it had been a law of nature that the effects of educa- 
tion should be inherited, then men would have been continually 
moulded to certain patterns; originality would have been bred 
out by the widespread influences of mediocrity in power, and 
that ever-present variety in art, in science, in intellect, in 
ethics, and in the higher and purer aspirations of humanity, 
would have been certainly diminished. And if it be said that 
the very bad would have been made better if educational in- 
fluences had been inherited, even this may be doubted; for 
in times which permitted so much that was bad, education 
often tended to increase rather than diminish the evil. On 
the other hand, w^e are more and more coming to see that none 
were all bad, and that their worst excesses were due in large 
part to the influence of their environment and the fierce temp- 
tations to which they were, and still are, so unnecessarily ex- 
posed. 

But it is when we look upon man as being here for the 
very purpose of developing diversity and individuality, to be 
further advanced in a future life, that we see more clearly the 
whole object of our earth-life as a preparation for it. In this 
world we have the maximum of diversity produced, with a 
potential capacity for individual educability, and inasmuch as 



THE PURPOSE OF DIVEPSTTY 420 

every spirit has been derived from tlio Deitv, onlv liuiited 
by the time at the disposal of each of us. In tlie sj)ir it- 
world death will not cut short the period of educational ad- 
vancement. The best conditions and opportunities will be af- 
forded for continuous progress to a higher status, while all 
the diversities produced here will lead to an infinite variety, 
charm, and use, that could probably have been brought about 
in no other way. 

This is also the teaching of modern spiritualism, and by 
this teaching its existence is justified and its truth upheld. 
Such teaching pervades all its best literature, of which Poe's 
Farewell to Earth, given through the trance speaker Miss 
Lizzie Doten, in 1863, is one of the most remarkable.^ He 
tells us of the educational value of much that we term pain 
and evil in the following lines : 

" Gifted with a sense of seeing. 
Far beyond my earthly being, 
I can feel I have not suffered, loved, and hoped, and feared in vain; 
Every earthly sin and sorrow I can only count as gain, 
I can chant a grand ' Te Deum ' o'er the record of my pain." 

Again, he shows us that struggle and effort are essential 
for progress there as here : 

*^ Human passion, mad ambition, bound me to this lower Earth, 
Even in my changed condition, even in my higher birth. 
But by earnest, firm endeavour, I have gained a height sublime; 
And I ne'er again — no, never! shall be bound to space or time; 
I have conquered! and for ever! Let the bells in triumph chime! 
* Come up higher ' ! cry the Angels. * Come up to the Koyal Arch ! 
Come and join the Past Grand Masters, in the Soul's progressive 

march, 
thou neophyte of "Wisdom ! Come up to tlie Poyal Arch ! '* 

1 Of the more serious books tlealing witli tlie ethics and j)liilosophy of 
spiritualism, I will only direct the reader's attention to two: Spirit 
Teachings, by W. Stainton Moses, M.A.; aii.l Psychic Thilosophy, as the 
Foundation of a Religion of Natiiral Law. hy \'. (,". Desertes. To such 
of my readers who wisli to obtain some knowledge of the higher aspects of 
modern spiritualism, I strongly reconunen«l these two works. 



430 THE WORLD OF LIFE 

In the preceding verse, however, he has given us the key- 
note to the future life, which he speaks of as — 

The land of Light and Beauty, where no bud of promise dies; 
and then continues — 



iC 



There, through all the vast Empyrean, 
Wafted, as on gales Hesperian, 
Comes the stirring cry of ' Progress! ' telling of the yet to be. 
Tuneful as a seraph's lyre, 
' Come up higher ! Come up higher ! ' 
Cry the hosts of holy angels : ' learn the heavenly Masonry : 
Life is one eternal progress : enter then the Third Degree ; — 
Ye who' long for light and wisdom seek the Inner Mystery/ " 



Conclusion 

In accordance with the views expounded in a former work, 
Man's Place in the Universe, I have fully discussed the evi- 
dences in plant and animal life indicating a prevision and defi- 
nite preparation of the earth for Man — an old doctrine, 
supposed to be exploded, but which,, to all who accept the view 
that the universe is not a chance product, will, I hope, no 
longer seem to be outside the realm of scientific inquiry. 

Still more important is the argument, set forth in some 
detail, showing the absolute necessity of a creative and directive 
power and mind as exemplified in the wonderful phenomena 
of growth, of organisation, and fundamentally of cell-structure 
and of life itself. This view is strengthened by a considera- 
tion of the nature of the elements which alone render life- 
development possible. 

Herbert Spencer enforced the idea of " variously conditioned 
modes of the universal immanent force " as the cause of all 
material and mental phenomena, and as the " Unknown Reality 
which underlies both Spirit and flatter." I have here ex- 
pressed the same views in a more concrete and intelligible 



THE PURPOSE OF DIVERSITY 431 

manner. This ^' Unknown Reality " is necessarily iiiiiiiitc and 
eternal as well as all-knowing, but not necessarily what we 
may ignorantly mean by '' omnipotent " or " benevoleiii " in 
our misinterjDretation of what we see around us. 1 have, I 
hope, cleared aw^ay one of these misinter])r('tati<jns and mis- 
judgments in my chapter Is Mature (Jruel ( 

But to claim the Infinite and Eternal Being as the one 
and only direct agent in every detail of the uuiverse seems, 
to me, absurd. If there is such an Infinite Being, and if (as 
our own existence should teach us) his will and purpose is 
the increase of conscious beings, then we can hardly be the 
first result of this purpose. We conclude, therefore, that there 
are now in the universe infinite grades of power, infinite grades 
of knowledge and wisdom, infinite grades of influence of liigher 
beings upon lower. Holding this opinion, I have suggested 
that this vast and wonderful universe, with its almost infinite 
variety of forms, motions, and reactions of part upon part, 
from suns and systems up to plant-life, animal life, and the 
human living soul, has ever required and still requires the con- 
tinuous co-ordinated agency of myriads of such intelligences. 

This speculative suggestion, I venture to hope, will appeal 
to some of my readers as the best aj^proximation we are now 
able to formulate as to the deeper, the more fundamental 
causes of matter and force, of life and consciousness, and 
of Man himself; at his best, already '^ a little lower than the 
angels," and, like them, destined to a permanent progressive 
existence in a World of Spirit. 



D. H. HILL LIBRARY 
North Carolina Stat* College 



INDEX 



Acidaspis dufresnoyi, 288 
Adaptation, some aspects of, 141 
Adaptations to drou<j;ht, 72; binls 

and insects, 143 ; not eflected by 

use, 280; of plants, animals, ami 

man, 329 
A^Jlusmtrufi felinus, early reptile, 215 
Agassiz, a., on deposition by 

Mississippi, 192 
Allegory, a physiological, 319 
Allotropy of elements, 417 
Alpine floras not exceptionally rich, 

38, 40, 8G 
Amblypoda, a sub-order of Ungu- 

lata, 235 
America, flora of tropical, 59 
American bison, former enormous 

population of, 124 
Ammonites, eccentric forms of, 288 
Amceba, description of, 361 
Amphibia, earliest forms of, 210 
Ancyloceras matheronianum, 290 
Andrews, Dr. C. W., discovers an- 
cestral forms of elephants in 

Egj'pt, 245 
AnimalSj numerical distribution of, 

89; much less sensitive than man, 

405 

Anoplotherid.^, ancestral rumi- 
nants, 245 

Anoplotheriuin commune, skeleton 



of, 244 



recognition-marks of, 



Antelopes, 

172 

ArchcBopteryx macriira, 230; sie- 

mensi, skull of, 231 
Arctic lands a birds' paradise, 151 
Argyll, Duke of, on humming- 
birds, 177 
Armstrong, Professor H. E., on 
importance of carbon, 393: on 
directive influences in growth, 

420 
Arrhenius, Professor, uu an eter- 
nal universe, 379 
Arsinoitherium zitteli, skull of. 240 
ASTROPOTiiERiA, extinct uniiulatcs, 

251 

433 



Atlantomxirua immanis, a huge dino- 
saur, 220 
Atoms, early ideas of, 417 
Al'STRALIA, extinct tnainniMls (if, 
25C 

Babirusa, tusks of, 29G 

Ballota nigra, local distiiljiitioii of, 
15 

Balsams, dyes, oils, etc., variety of, 
352 

Bate-Hardy, ;Mr. W., on arrange- 
ment of identical atoms in carbon 
compounds, 384 

Beccari, Dr., on forest flora of 
Borneo, 56 

Beetle mimicking wasp, 169 

Beetles, number known, 91 ; pecul- 
iar British, 135 

Being, grades of between us and 
Deity, 423 

Bird, earliest known, 309 

Bird and insect co-adaptation, 142; 
teachings of, 164 

Bird's wing, the ideal aimed at in, 
308; a feather, detailed structure 
of, 309; its anniuil regrowth, 311 

Bird-colour, extreme diversity not 
of survival value to them, 344 

Bird-migRj\tion, origin of. 159 

Birds, of New CJuinea and Borneo, 
53; species of, 93; of six geo- 
graphical regions, 96; peculiar to 
Britain, 13.'), 13t): arrival of. iti 
Arctic regions. 151, 153: number 
of species in Arctic region-^. l.")7: 
recognition-marks of. 175: the 
earliest, 229; recently extinct. 
200: loss of teeth in m'odern. 2;il 

Birds and insects, proofs of or- 
ganising mind, 309 

l?iKi)S OF Parauisk, new types of, 

2!)7 
Bison, former great population of 

in America, 124 
BoLis. Mr. II.. on flora of ( ape 

])eniii>^iila. 40: on orcliids of ('aj)e 

peninsula. 41 



434 



INDEX 



Borneo, rich forest flora of, 49; 

birds of, 51 
Botanical, reserves, advantages of 

small, 82 
BovERi's experiments on echini, 373 
Brain-cavity of Dinocerata very 

small, 239 
Brains of early vertebrates, small, 

291 
Brazil,, richness of flora of, 75 
Britain, peculiar animals and 

plants of, 135 
British India, flora of, 47; chief 

natural orders of, 48 
British plants, numerical distribu- 
tion of, 24, 27; of limited range, 

26 
Brittan, Mr. L. K, on flora of 

Jamaica, 67 
Brontosaurus excelsus, skeleton of, 

221 
Butler, Sir W., on mosquito- 
swarms, 146 
Butterflies, recognition by, 181, 

185 
Butterexy, stages of development 

of, 325; scales on wings of, 325 
Butterfly and caterpillar, diverse 

structure of, 321 



Caltha palustris, wide range of, 19 

Cambrian age, first known life of, 
207 

Campanula isofpTiylla, small range, 
20 

Cape Colony, flora of, 75 

Cape peninsula, rich flora of, 40 

Cape Region, rich flora of, 35, 77 

Carbon, the mystery of, 390; prop- 
erties of, 391; in the ocean, 392 

Carnlvora, early forms of, 240; ex- 
tinct South AmericaUj 249 

Cavies, numerous extinct, 252 

Celebes, flora of, 55, 85 

Cell, the mystery of, 361; charac- 
teristics of, 363; implies an or- 
ganising mind, 364; described by 
Professor Lloyd-Morgan, 364 ; 
Weismann's description of a di- 
viding, 365; Weismann's state- 
ment of its powers, 369 

Cell-problem, concluding remarks 
on, 376 

Ceratites nodosus, 289 

Ceratosaurus nasicornis, skull of, 
222 

Cetiosaurus leedsi from Oxford clav, 
220 



Challenger voyage defines area of 
deposition, 192 

Chemical problems of water, 393; 
nomenclature, illustration of com- 
plexity of, 418 *u 

China and Coreaj flora of, 34 

Christianity, gradual rise of a 
purer, 302 

Cities, the "wens" of civilisation, 
308 

CoaLj wide distribution of palaeo- 
zoic, 212; prepared atmosphere 
for higher life, 213 

Cobbett, William, on "wens," 308 

Cockerell, on tropical species as 
compared with temperate, 104 

Coleoptera, number of British, 90; 
number known, 91 

Colour, for concealment, 169; ex- 
tremes of, 298; of flowers sup- 
posed to show inedibility, 332; 
purpose of in nature, 334; of 
plants and animals in relation to 
man, 340; our sensations of, an 
argument for design, 348, 349 

Colour-sense not identical in birds, 
mammals, and man, 325, 342 

Colours of butterflies, uses of, 183 

Colours and ornaments of males, 
how caused, 282 

Compounds, inorganic, number of, 
418; number of organic (artifi- 
cial), 419 

Condylarthra, 235 

Conocoryphe sultzeri, 287 

Continental extensions, appendix 
on, 268; great difficulties of, 269, 
270 

Continents, how built up, 196, 198 

Coryphodon, an early ungulate, 235 

Creators of matter and life not 
necessarily omnipotent, 422 

Creodonta, early carnivores, 242 

Crioceras emerici, 289 

Crookes, Sir W., gives an example 
of complex chemical nomencla- 
ture, 418 

Cruelty of nature, supposed, 398 

Crustacea, early appearance of, 
210 

D^dicurus, giant extinct arma- 
dillo, 252 

Darwin on flora of a very small 
area, 87; on increase of elephant, 
123; on Porto Santo rabbits, 137; 
on the uses of colour to plants, 
329; on cross-fertilisation of 
flowerSj 330; on war of nature. 



INDEX 



435 



399; on intelligent cause of the 

universe, 422 
Darwinism, extensions of, 271 
Deane, Mr. H., on flora of Sydney, 

New South Wales, 42 
De Candolle, a., on botanical gco^j;- 

raphy, 18, 24; botanical regions 

of, 20 
Definition of life, 3 
Denudation, rate of, measured, 189 
Deposition, area of, 191 
Determinants, meaning of, 293 
Development, reversal of, 245; 

cases of extreme, 29G 
Diagram of human stature, 116; of 

variation of rice-bird, 118; of 

nuclear division, 370; of isomer- 
ism, 384 
Dicynodon lacerticeps, early reptile, 

214 
Dimetrodon, extinct reptile from 

Permian of Texas, 215 
Dinocerata, " terrible horned 

beasts," 236 

DiNOSAURIA, 217 

DiPLODOCUS, skull of, 222 

Diplodocus carnegii, skeleton of, 
220 

Diprotodon australis, skull of, 257 

DiPTERocARPS, abundance of in 
Borneo, 56 

Directive agency not explained by 
Darwin's *' pan-genesis " nor any 
other theory, 319, 358; indica- 
tions of, 354; at work, 373, 374 

Distribution of species result of 
continuous adaptation, 103 

Domestic animals, uses of, 305 

Dresser, Mr. H. E., on birds breed- 
ing in Arctic regions^ 155; on 
mosquitoes as food for birds, 157 

Drosera rotundifolia, wide range of, 
18 

Drought, adaptations of plants to, 
72 

DwiNA river, rich deposits with 
early reptiles, 214 

Earth's surface changes a cause of 
evolution, 187 ; thickness of crust 
of, 194; crust floats on melted in- 
terior, 195; eff'ect of cooling ami 
contracting, 19G; surface-motions, 
long persistence of, 200 ; remlered 
habitable by water, 3!)6 
Eccentricity in nature, 298 
Eccles, Dr. R. G., on uses of par;i- 
sites, 413 



Echinus microtuhcrculutus, egi^ of, 
373 

Edentata, extinct S. American, 252 

Educational elTects. unlimited in 
tiie spirit-worlfl. 4'JM 

Elements in nlalion to tiie life- 
\\orI(l, 3S:{ : important and unim- 
portant, 385; list of important, 
38(i ; in iclation to man, 387 

Elephants, rate of increase of, 123; 
the origin of, 244 ; diagram of 
development of, 24(1 

Elephas gatusa, enormous tusks of, 
287; prim'ujcniuHy .skeleton of, 
249 

Eternity as explaining evolution 
fallacious, 37!> 

European floras in dilTerent lati- 
tudes, 32; compared, 36 

Evolution, motive power of or- 
ganic, 187 

Extensions of Darwinism, 271 

Extinction of pleistocene mam- 
mals, cause of, 261 

Feathers, marvel and mystery of, 
309 

Female choice, new argument 
against, 184 

Ferns, extreme abundance of, in the 
Philippines, 54 

Fishes, peculiar British, 135; the 
earliest known, 208; types of 
tails of, 209 

Fletcher, Mr. L., on inorganic 
compounds, 419 

Flight of birds and insects com- 
pared, 94 

" Flora Orientalis," species in. 34 

Flora of China, 34; of Chile, 35; 
of Cape region, 35; of tropical 
Asia, 46; of British India, 47; of 
;Malay Peninsula, 47; of Borneo, 
49; of Indo-Ciiina, 50; of Malay 
Islands, 50; of New C.uinea, 55; 
of Philij)pine8, 54; of CeleU's, 55, 
85; of (.4)ueensland, 58; of trop- 
ical Africa, 59; of Madagascar, 
59; of tropical America. 58, 59, 
()5 ; of lirazil, 63; of Mexico luid 
Central America, 64; of Jamaica, 
67; of Trinidaii, 67; of CJulapa- 
gos Islamls. 67; of I^igoa Santa. 
67, 77; of Penang, 79; of Kain- 
bangan Islamls, 80; of Pange- 
ranifo. 81 ; of mountains in .la- 
pan. SCf. of very small areas. 87 

I'l.ouAS of (liirercnt regions com- 
parctl. 11; of counties compared. 



436 



IKDEX 



27 ; of some parishes, 28 ; of small 
areas, 28, 77 ; of temperate zones 
30; cause of richness 
35; warm temperate 
compared, 3G; of European small 

and 
86; 



compared, 
of some. 



areas, o/ ; of mountains 



plains compared, 38, 40, 
extra-European temperate, 39 

Flowering plants, peculiar British, 
134 

Flowers, al)undance of, within Arc- 
tic circle, 153 

Food of young birds, 142 

Forbes, Mr. H. 0., on self-fertilisa- 
tion of orchids, 332 

Forest reserves, advantages of 
small botanical, 79 

Fruits, colour of, 336 

Galapagos, flora of, 67 

Galton's law of heredity, 110 

Gamble, Mr. J. T., on flora of 
Malay Peninsula, 47 

Gardner, on flora of Brazil, 77; 
on supposed greater richness of 
mountain floras, 80 

Gatke, Herr, on bird-migration at 
Heligoland, 161 

Geese moulting in Arctic regions, 
148 

Gentiana verna, one locality in 
Britain, 26 

Geological record, account of, 203; 
its three well-marked periods, 
204; the teaching of. 300 

Geology, as influencing evolution, 
188 

Germinal selection, 281, 292, 296 

Glass essential for science, 338 

(ilyptodon clavipes, skeleton of, 253 

Glyptodontid.e, extinct armadillos, 
252 

Grant Allen on insects and colour 
of flowers, 333 

Grey plover's nest in Arctic re- 
gions, 156 

Griesbach, on Mediterranean flora. 
34; on Brazilian flora, 76 

Growth, the nature of, 315; by cell- 
division, 316; admitted to be in- 
explicable, 371; by cell-division, 
what it implies. 
Dr., on 



Gunther, 
94 

Haeckel 
human 

ether, 7, 
scions. 



373 
species 



of birds. 



on consciousness, o ; on 

nature, 6; matter and 

,8; on soul-atom uncon- 

358; his carbon-theoiv of 



life, 391 



Hamites rotundity, 290 

Hardy, Mr. W. B., on complexity of 
proteid molecule, 383 

Hartert, Dr., on peculiar British 
birds, 135 

Hayati, Mr., on floras of Japanese 
mountains, 39, 40 

Heat, rate of increase in deep bor- 
ings, 194 

Heligoland and migrating birds, 
160 

Hemsley, W. B., on flora of Central 
America, 61 

Heredity a universal fact, 109; 
Galton's law of. 110 

Heteroceras etnerici, 289 

Hooker, Sir Joseph, on flora of 
British India, 47; on primary 
floras, 65; on rich flora of Pe- 
nang, 77; on floras of very small 
areas, 87 

Horns as recognition-marks, 173 

Horses, extinct South American, 
250 

Hudson, W. H., on field mice in 
Argentina, 132 

Human character, diversity of. 426 

Hutton, Capt., on recognition- 
marks, 178 

Huxley, Professor, on nature and 
origin of life. 9; on matter and 
spirit, 10; on crueltv of nature, 
400 

Hycenodon cruentus, skeleton of, 
242 

Hyopotamns hrachyrhynchns, skele- 
ton of, 243 

Ichthyopterygia, 223 

Ichthyosaurus, paddles of, 224 

Ichthyosaurus communis, skeleton 
of, 224 

Iguanodon hemissartensis, 
of, 218; skull of, 219 

Increase in plants and 
121 

Indo-China, estimate of flora of, 50 

Inheritance of educational results 
would have checked diversity, 427 

Inorganic substances, varietv of, 
416 

Inostransevia, huge carnivorous 
reptile, skull of, 2l6 

Insect life of secondary period, 228 

Insect pests, uses of, 142 

Insects, known species of, 91; pe- 
culiar to Britain, 135; earliest 
known. 211; and their metamor- 
phosis, 321 



skeleton 
animals, 



i:tTDEX 



437 



Insects and birds, co-adaptation of, 

143 
Irish deer, skeleton of, 287 
Isomerism explained, 385 

Jack-rabbit, E. S. Thompson on, 

172 
Jamaica, flora of, 67 
Japan, mountain floras of, 40 
Java, rich flora of, 80 
JoRDAX, Dr. K., on phosphorescent 

colours in lepidoptera, 347 
JuDD, Professor, on strange forms 

of ammonites, 87 

Kambangan island, rich flora of, 80 
Karoo formation, reptiles of, 213 
Kearton on increase of rabbits, 122 
Kerner, Dr. A., on power of in- 
crease of plants, 121 ; on the in- 
sect enemies of flowers, 331 ; on 
"vital force/' 356; on arrange- 
ment of atoms in the carbon- 
compounds, 384 
KooRDERS, Dr., on the flora of 
Celebes, 55, 85; on rich floras of 
small areas in Java, 79 

Lagoa Santa, flora of, 67, 75 

Land-shells, peculiar British, 135 

IjAtitude as influencing floras, 31 

Lemming, periodical migrations of, 
128-30 

Lepidoptera, number of British, 89 ; 
number known, 91 ; peculiar 
British, 135; wealth of colour in, 
345-47 

Life, definition of, 3 ; Haeckel on, 
4, 7 ; the cause of organisation, 
8; reactions of animal and plant, 
304 ; the sole cause of life, 306 ; a 
suggestion as to origin of, 422 

Life-deveix)pment of mesozoic era, 
231; conclusion on, 299 

Life-forms, causes of diversity of, 
415 

Life-world, progressive development 
of, 203 

Limestone, progressive increase of, 
234 

lAthospermiim gastoni, narrow range 
of, 19 

Llamas, extinct S. American, 240 

Lloyd-Moroan, statement of theory 
of germinal selection, 292; on 
rapid cell-growth, 375 

Ltdekker, jSIr., on Patagonian mar- 
supials, 241; on affinities of 



American and Australian marsu- 
pials, 265 
Lyell, Sir C, on causes of extinc- 
tion, 264 
London, how to stop growth of, 308 
LowNE, Mr. B. T., on development 
of blow-fly, 323 

Machcerodus neogcpua, skull of, 286 

Macrmichenia patachonica, 251 

Macroscaphiies ivanii, 290 

Madagascar, flora of, 59 

M cerifherium lyonsi, skull of, 244 

Malay Islands, flora of, 50; in- 
sects of, 92 

Malay Peninsula, table of chief 
orders of plants, 47 ; character- 
istic plants of, 48 

Mammalia, teachings of pleistocene, 
265 

Mammals, extinct Australian, 256 

Man, the cause of extinction of 
pleistocene mammals, 268-70; the 
glory and distinction of, 402-06; 
the most sensitive of organisms, 
409 

Mantell, Dr., discovered extinct 
reptiles in Kent, 217 

Marsh, Professor O. C, on Bronto- 
saurus, 220; on Dinocerata, 237; 
on small brains of early mam- 
mals, 239; causes of extinction of 
mammals, 263 

Marsupials in Patagonian miocene, 
240; of the Australian type still 
living in the Andes, 264 

Martius's flora of Brazil, 63 

Mastigophora, 362 

Mastodon in S. America, 254 

Mastodon americanus, skeleton of, 
247 

Mastodons, less developed ele- 
phants, 246 

Max Verworu on chemistry of pro- 
toplasm, 316; on vital force, 317 

Mediocrity, recession towards, 117 

^Mediterranean flora, species in, 34 

Megatherium, extinct ground sloth, 
252 

Megatlierium giganteum, restoration 
of, 254 

Mendelism and mutation inefficient 
as substitutes for Darwinian evo- 
lution, 133 

]\rKRRiLL, Mr. E. D., on flora of the 
Pliilii)pines, 54 

Mesozoic era, 213; mammalia of, 
228: insects of, 228; life-develop- 
ment of, 231 



438 



INDEX 



Metals, the seven ancient, 387; es- 
sential for civilisation, 388 

Metamorphosis of insects, 321 

Mexico and Central America, flora 
of, 64 

Microbes, use of in nature, 412 

Migration, origin of bird, 159; 
facts and inferences, 160-63 

Mimicry, 169 

Minahassa, N. Celebes, flora oF, 55, 
85 

Mind and purpose in life-develop- 
ment, 299 ; and life, different de- 
grees of, 307; produces brain, 307 

Minerals, number of species of, 
418 

Mivart, St. George, on recognition- 
marks, 179 

Morgan, Professor L., on germinal 
selection, 292; on rapid cell- 
growth, 375 

Mosquitoes, uses of, 145; descrip- 
tion of Arctic, 146; food for most 
young birds, 151 

Mosses and hepaticse, peculiar 
British, 135 

Mountain floras, in Japan, 40; not 
richest, 97 

MtJLLER on insect-fertilisation of 
flowers, 333 

Mylodon, contemporary of man, 
254 

Mylodon rohii^tus, skeleton of, 254 



Narwhal's tusk an extreme devel- 
opment, 296 
Natural selection, illustrative cases 

of, 134; of sparrows at Ehode 

Island, 138; process of at Porto 

Santo, 138 
Nature, the sanctity of, 301; our 

defacement of, 301; is it cruel? 

398 
New Guinea, biologically unique, 

51 ; flora of, 55 : richness of its 

bird fauna, 96, 98 
Newton, Professor A., on passenger 

pigeon, 128 
North American floras in various 

latitudes, 34 
Nototherium, extinct Australian 

wombat, 260 
Nuclear division, diagram of, 370 
Nucleus, importance of, 373 
Nummulites, 363 
Nuts, why intended to be eaten, 

337 



Ocean, carbon in, 392 

Orchids, abundance of in Cape 
Peninsula and New South Wales, 
41 ; in British India, 48 

Okeodontid.e, early American rumi- 
nants, 242 

Organising spirit the cause of life- 
production and control, 425 

Organs, beginnings of new, 271 

Ornithosaltiia, 224 

Pain, its purpose and limitations, 
398; a product of evolution, 404; 
beneficent purpose of, 412; where 
useless does not exist, 413; in na- 
ture, Huxley's exaggerated view 
of, 400, 414 
Pal.eomastodons, early elephants, 

244-45 
Palceotherium magnum, restoration 

of, 244 
Paleozoic era described, 206 
Palms, abundance of in the Malay 
Peninsula, 47; in the Philippines, 
54 
Pangerango, Mount, rich flora of, 

81 
rarndoxides hohemicus, 287 
Pariasaurus hainii, skeleton of, 214 
Passenger pigeon now extinct, 125; 
enormous population of less than 
a century ago, 125 
Penang, rich flora of, 79 
Phascolotherium, 231 
Phenacodiis primcBvus, early ungu- 
late, 235 
Philippines, rich flora of, 54 
Physiological allegory on growth, 

319 
Plant-cell, Kerner on, 371; iden- 
tity with animal cell, 372 
Plants of wide distribution, 21; 
abundance of compared, 23; of 
very small areas, numbers of, 98 
Pleistocene mammalia, teachings 

of, 259 
Plesiosaurus macrocephalus, skeleton 

of, 222 
PoE, extracts from supposed im- 

pressional poem by, 428 
Porto Santo rabbits, newly formed 

species, 137 
Potentilla rupestris, one locality in 

Britain, 27 
PouLTON, Prof. E. B., on beginnings 

of new organs, 272 
Primates, fossil species of South 
America, 249 



i:n^dex 



439 



Primula imperialis, small range, 19 

Proteid molecule, complexity of, 
383 

Prothylacinus, a Patagonian mar- 
supial, 240 

Protoplasm, its chemical nature, 
315 

Pteranodon occidentalis, skeleton of, 
226; longiceps, skull of, 227 

Pterodactyl, restoration of long- 
tailed, 22G 

Pterodactylus spectahilis, skeleton 
of, 225 

Ptychoceras emeridanum, 290 

Purpose of our universe to produce 
variety of human character, 299, 
421 

Pyrothebia, 251 

Queensland, flora of, 58 

Rabbits, increase of in Australia, 
123 

Radiolaria, 362 

Radium, its rarity and uses, 389 

Ramsay, Sir A., on life of the Cam- 
brian age, 207 

Recognition by butterflies, 181 

Recognition-marks important for 
evolution, 168; explained, 170; 
objection to answered, 178; gen- 
eral conclusions on, 185 

Religion, gradual rise of a true, 
302 

Reptiles, earliest, 214 

Reptilian life of secondary period, 
227 

Retrogressive development in 
birds, 309 

Rhizopoda, 362 

Rice-bird, diagram of variation of, 
118 

Ridley, Mr., on flora of Singapore, 

79 
River-basins, rate of denudation of, 

189 
Roscoe, Sir H., on properties of 
carbon, 388; on water in relation 
to life, 391 

Saleeby, Dr., on eternity as an ex- 
planation, 379 

Sap, extreme production of, 299 

Sauropterygia, 223 

Scales on wings of buttciilics, .'l-i.") -. 
apparent purpose of, 327 

Scelidosaurus harrisoni, skeleton of. 
218 



Sceloditherium leptocephalum, skel- 
eton of, 255 

ScLATER, Dr. P. L., on species of 
birds, 94 

Seeboiim, H., on food of birds in 
Arctic regions, 146 

Seton-Tiiompson on recognition- 
marks, 172 

SiiARPE, Dr. B., on species of birds, 
94 

Shipley, A. E., table of described 
animals, 99 

Simethis bicolor, one locality of in 
Britain, 27 

Singaporp:, flora of, 79; destruction 
of forest in, 85 

Sisymbrium sophin, power of in- 
crease of, 121 

Small-brained animals, purpose of, 
306 

South Africa, Cape Region, flora 
of, 79 

South America, tertiary mammals 
of, 249 

Spalacotherium, 229 

Sparrows at Rhode Island, work of 
natural selection on, 138 

Species defined, 12; distribution of, 
13; uncertainty of limits of, 25; 
rarity of precedes extinction, 26; 
number of, in relation to evolu- 
tion, 100; variation of. 113; ex- 
tremely common, 114; to be seen 
everywhere, 115 

Spencer, H., on co-ordination of 
variations, 275; reply to, 276, 
277; his " unkno^^^l reality" 
more concretely expressed, 430 

Spirit-life described (inspiration- 
ally) by Poe, 428 

Springbok, curious recognition- 
mark on, 174 

Spruce, Dr., on rich flora of Ama- 
zon, 61 

Sterrolophus fJabeJIatus, skull of, 
219 

Stone-curlews, recognition marks 
of, 175 

Sydnetx", extreme abundance of or- 
chids near, 41 

Table of De Candolle's botanical 
regions, 20; of chief natural 
orders in various floras, 22; of 
number of species in large and 
small areas. 28; of numln^r of 
species in difTerent latitudes, 31: 
of floras of European oonntries 
according to latitude, 31; of 



440 



INDEX 



floras of XortH American areas, 
32; of warm temperature floras, 
36; of European floras of small 
areas, 37; of extra-European 
temperate floras, 39; of large 
tropical floras, 45; of chief orders 
of flora of British India, 47; of 
chief orders of tropical Sikkini. 
48; of chief orders of Malay 
peninsula, 48; of chief orders of 
the Philippines, 54; of chief or- 
ders of Celebes, 56; of chief or- 
ders of Madagascar, 59; of chief 
orders in tropical American 
floras. 64 ; of chief orders of Mex- 
ico and Central America, 65; of 
chief orders of Nicaragua to 
Panama, 67; of chief orders of 
Lagoa Santa, 71; of number of 
species in tropical floras of small 
area, 77 ; of number of species in 
temperate floras of small area, 
77; of distribution of lepidoptera 
in Britain, 89; of distribution of 
coleoptera, 90; of described 
species of orders of insects, 91; 
of species of birds in Europe, 95; 
of species of birds in zoological re- 
gions, 96; of described species of 
living animals, 99; of percentage 
of mean error of variation. 121 ; 
of peculiar sub-species of British 
birds, 136; of rate of lowering of 
river-basins, 189 

Teeth, gradual loss of during de- 
velopment, 291 

Temperate floras compared, 30, 36, 
39; floras, small areas, 77 

Temperature - adjustments of 
earth's surface. 202 

Tertiary period, life of, 235 

Tetrabelodon, restoration of, 245 

Tetrahelodon angustidens, skeleton 
of, 246 

Theriomorpha, beast-like reptiles 
of Karoo formation, S. Africa, 
213 

Thompson, E. Seton, on recogni- 
tion-marks, 172 

Thomson, Prof. J. A., on deter- 
minants, 293; on mechanics of 
the germ-plasm, 370; on nature's 
stern methods, 399 

Thought-transference the agent 
in life-production and guidance, 
425 

Thylacoleo carnifex, skull of, 258 



Titanotherium rohustum, skeleton 
of, 238 

Toxodon platensis, skeleton of, 250 

TOXODONTIA, 251 

Truchycerafiaon, 289 

Tkicoxodon, 229 

Tkilobites, early and late forms 
of, 287 

Tkixiuad, flora of, 68 

Thopical floras of the world, 43; of 
large areas compared, 45; small 
areas, 77 

Tropical and temperate vegetation 
compared, 105 

Thopical vegetation, causes of rich- 
ness of, 106 

Tylor, a., on rate of denudation, 
189 

Uintatherium ingens, skeleton of, 
236; cornutum, skull of, 237 

Ungulata, early forms of, 235; 
extinct South American, 249 

Universe, purpose of the stellar, 
299 ' 

Upheaval produced by contraction, 
197 

Variation of mind as great as of 

body, 114; as shown in curve of 

stature. 116; of the various parts 

of a bird, 118 
Variation of species, 113 
Variations, co-ordination of, 275 
Variety in nature, purpose of, 300; 

the law of the universe, 415; 

cause and purpose of, 420 
Vegetable products in relation to 

man, 350 
Vegetation, differences of tropical 

and temperate, 105; early, 210 
VernoNj Dr. H. M., on variation, 

119; on parts of human body 

varying independently, 120 
Vertebrates, special features in 

development of, 291 
Vital force. Max Verworu on, 316; 

Dr. A. Kerner on, 356 

WARiiiNG, Professor Eug., on flora 
of Lagoa Santa, 67, 74 

Water in relation to life, 394; com- 
plex problems of, 395; as prepar- 
ing earth for man. 397 

Weismann's theorv of germinal se- 
lection, 292 

Weymouth, abundance of ammon- 
ites at. 288 



INDEX 



441 



Wilson, Alexander, on numbers of 
passenger pigeons, 125, 126 

Winter transformed into summer, 
153 

Wood, various qualities of, 352 

Woodrufffc-Peacock on detailed 
floras, 15; on meadow and pas- 
ture plants, 17 

Woodward. Dr. A. S., on progress- 
ive developments of some charac- 



ters, 285; on small brains of early 
vertebrates, 270 
Wulfenia carinthiaca, small range 
of, 19 

X-RAYS prove use of pain, 411 

Zoological regions, species of birds 
in, 96 



i 



i