The evolution of man and his mind. A history and discussion of the evolution and relation of the mind and body of man and animals

Front matter

lV,B *.

THE

EVOLUTION OF MAN

Preface

While a civil engineer and government surveyor of public lands the author became familiar with the workings of the land and Indian bureaus of the interior department in Washington, D. C, and incidentally the other offices of general, state and territorial control, and realizing the impossibility of doing conscientious work while associated with the politicians who filled most of the places, in 1873 the field of medicine was substituted, and after graduation a specialty was made of nervous and mental disease. In order to further such studies the author secured a position as pathologist to the Chicago County Insane Asylum, and during three years' service there and later as superintendent of the Illinois Eastern Hospital for the Insane he discovered that the politics controlling such places was inexpressibly worse than what he found elsewhere. As reform endeavors availed nothing, a determination was made to discover the reasons for the too frequent brutalities in public charity institutions, and the apathy of citizens concerning them. The studies expanded into this volume, passing far beyond their original bounds, but rigidly confined to this world, with only incidental mention of anything beyond ; though by inference the earth is but a small portion of the universe.

Hallam, in the preface to his Literature of Europe, remarks that : "An author who waits till all requisite materials are accumulated to his hands is but watching the stream that will run on forever and though I am fully sensible that I could have much improved what is now offered to the public by keeping it back

IV PREFACE.

for a longer time, I should but then have had to lament the impossibility of exhausting my subject."

The author finds encouragement in thinking with Carlyle, that : "If a book come from the heart it will contrive to reach other hearts. All art and author-craft are of small account to this."

70 State St., Chicago, February, 1903.

CHAPTER I.— Earliest Man

Successive glances are taken at the conditions of our immediate and remote and then still remoter ancestry, until we reach savages in the ice ages. Frankland's theory of a hot primeval sea and Le Conte's critical periods in the course of the earth's development afford some of the bases upon which are gradually built up the earliest races of men, those of the stone age, the dwarfs, the Turanians, Africans, Malays, etc. The non-Aryans and pre-Aryans. The bronze and iron ages, the hunting, pastoral and farming stages of race progress. The separate origin of the different races, their migrations and subsequent intermixture; early civilization in America being regarded as indigenous.

CHAPTER II.— The Aryans

The primitive Himalaya range, the "Roof of the World." from which flows the Oxus river along which was located the legendary Aryan paradise whence the Aryan settlers were driven by floods, droughts, savages and sand storms, migrating as Celts, Greek-Romans. Teutons and Slavs, from whom came the present German, French, English. Irish, Russian and Scandinavian peoples, as well as the Persians and high caste Hindoos.

The growth, decline and extinction of tribes and nations, with the rise of new social organizations under various nanus.

CHAPTER III.— The Semites

Babylonian civilization ten thousand years ago, Hilprecht's excavations in the Mesopotamian valley, royal and mercantile libraries being unearthed and translated which were written ages before the days of Abraham. The Hebrews, Assyrians, Phoenicians and Egyptians and what Europe owes to them. The Aryan barbarians deriving their alphabet, numerals and rudiments of arts and sciences from the Semites.

CHAPTER IV.— Middle Ages

The behavior of a wilderness full of apes compared with the gluttony, rapacity and cruelty of the classical periods. Slow evolution of ideas while Rome was "governed" by rulers who were often insane, knaves and fools. A survey of the period from Commodus to Constantine during which soldiers elected and murdered emperors. The rise of Charlemagne and the Franks when Germanic civilization grew upon the ruins of Roman power. Monasteries good and bad, and schools and the growth of ideas of freedom in the Feudal periods and during the crusades. The escape of Eng-

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VI TABLE OF CONTENTS.

land through Magna Charta and the inheritance by America of Germanic ideas of freedom preserved in England through the barons finding it to their interests to join with the people against the king.

French miseries, Joan of Arc, the Gabelle, the Bastille, etc. The loss by Germany through Romish corruption of the ideas of freedom it gave originally to the world.

CHAPTER V.— Evolution

Formation of plants and animals from the elements, development of the lowest animals into birds, apes and men. Pithecanthropus, the missing link found in Java. The American horse and other exterminated species. Birds with lizard ancestors ; man-like-apes and ape-like-men. The various mountain centres of primitive races ; capped with ice these ranges protruded from a hot sea. Natural and sexual selection which with labor division built up the present conditions about us.

CHAPTER VI. — Heredity and Degeneracy

Ancestral pride is not justified in going very far back. Racial peculiarities. Specialized animals with generalized ancestors. Effects of consanguine and early marriages. Aryan features in children. Chemistry of heredity. Royal and other degenerates.

CHAPTER VIL—Superstition,

The superstitions of animals, children and savages. Ceremonies of dogs and monkeys. The worship of animals by the ancients ; the mythological folk lore when analyzed affording accounts of early races. Superstitious beliefs and worship have a natural history, and cruelty has been associated with religions from earliest periods ; the gradual culmination of old religions in the modern ethical, and the slow improvement and purification of extant ideas of omnipotence.

CHAPTER VIII. — Evolution of Language and Writing

How birds, monkeys and other animals talk and what they say. The development of music with other means of emotional expression. Speech derangements from brain troubles. Dialects may grow into languages and if fittest to survive may be perpetuated though modified. Max Miiller on the origin of languages, and the few and simple Aryan roots from which European languages evolved. Ideas independent of words.

The early pictographic or sketch writings of savages, the hieroglyphs and other symbolic writings, the Babylonian, Egyptian and other character writing from which descended our alphabet and numerals, which are still imperfect ; history of books and origin of family names.

The speech centre in the brain and its gradual development and association with other brain parts.

CHAPTER IX.— Hunger and Love

The derivation of the mating faculty from primitive hunger; relation of assimilation and propagation, the seasons and battles of mating, the

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courtship of birds, fishes, insects and other animals, the universality of music in courtship of man and animals. Chaperonage ; woman as property in civilized countries and as a tyrant in some barbarous countries where each female is entitled to several husbands. The delusions of love ; primary ancestral attraction, the chemistry and biology of love, natural and unnatural affections, perversions, inversions and arrests of development of the propensity.

CHAPTER X.— Acquisitiveness

The origin of selfishness traced to its chemical source as an unavoidable and necessary attribute of all life and of even the atoms from which life develops. Altruism being merely a higher developed and more rational selfishness.

CHAPTER XI.— Development of the Mind

Mental traits of the infant, youth and adult in their relations to brain development.

CHAPTER XII— Evolution of the Brain

An account of the results of modern research in brain function by which has been disclosed that separate parts of the body are governed by special centres in the brain, and that between the lowest animal and the highest may be traced a gradual development of brain parts and structure in keeping with increase of intelligence.

The relations of brain and mind.

CHAPTER XIII.— The Senses and Feelings

Development of the senses of touch, hearing, smell and taste and their relation to pain and pleasure.

CHAPTER XIV. — The Instincts and Emotions. Among desires in general the inborn instinct to move about is primary. The desire for rest impelling to sleep also properly regarded enables such important functions as bodily movements and sleep to be discussed from new vantage ground. The potent instincts of fear, courage, anger, revenge, cruelty, curiosity, imitation, dishonesty and even the developed instinct of honesty are capable of being analyzed as animal phenomena and followed out from their beginnings in the lower forms of life. The creation of habits that may descend to offspring is described as a factor in heredity and in the revolution of individuals and nations.

CHAPTER XV.— The Intellectual Faculties

Under this division some of the matters treated are reason, judgment, intuition, memory, imagination, association, the generalizing ability, logic natural and artificial, and the will power.

CHAPTER XVI.— Mental Diseases

Causes of insanity. Deformities of the brain, blood supply defects to brain. Delusions, hallucinations and illusions explained.

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CHAPTER XVII.— Character

The influence of natural selection and survival of the fittest, the effects of education and the bearings of physiognomy and allied matters are studied to enable a better comprehension and appreciation of the complex nature of man. National traits are assigned to special causes, also.

CHAPTER XVIII.—Sociology

The changes made in history of peoples by wars, plagues, slavery, education, organization, philanthropies and co-operative movements that are mostly failures because the experience of the past it not utilized. The evolution of industries and the professions and the social organisms generally with special reference to parasitism and mutualism are appropriately handled.

CHAPTER XIX.— Analogy

The remarkable relationship of all natural events. Law of relativity. Physics and chemistry of life and mind. The social organism constructed from the individual elements. Analogies of society and animals. The universal relationship.

CHAPTER XX.— Conclusion

A summary of the preceding chapters is made to enable a grasp of the contents in their general bearings.

THE EVOLUTION OF MAN AND HIS MIND.

Chapter I. Earliest Men

You will sometimes hear old folks express a wish for a return of the "good old days" of their youth. This disposition of old people to regard recent times as inferior to remote periods is recorded as universal and as a senile characteristic as far back as we can go in history. A little reflection shows that modern times are better than the ancient.

Recently there were no electric or gas lights, no electric cars or telephones, horses pulled the street cars. There were no typewriters, bicycles or automobiles, no ice-machines, no modern battle-ships, when wooden "men-of-war" moved with sails. When the nineteenth century opened there were no steam-cars or steamships. Candles dimly lighted houses and churches that were poorly heated in winter; there were no postage stamps, steel pens, friction matches, sewing machines, photographs, city sewerage, hard coal fires, and machinery of all sorts was very simple, while fruits, vegetables or meats were not canned.

But the nineteenth century was progressive beyond preceding times, and progress is one of the forms of evolution, the evidences of which are all about us. Today in the world's history we have telegraphs, railways, steamships. Voyages at sea are now made in a few days where formerly sailing vessels used many weeks to go the same distance. We have the daily newspaper and engravings so cheap as to be within the means of the poor.

Yesterday, so to speak, there were none of these things. Horses pulled clumsy stage coaches through muddy roads, printed books were unknown. Fulton and Watts had not thought out their primitive engines. Step by step the conveniences of to day were evolved by gradual, toilsome improvements upon past things and methods.

Half a thousand years ago America was unknown to Europeans, unless the Vikings knew of it. London, Edinburg, Paris were unpaved, torch-lighted ; their streets were infested with robbers and assassins. And yet back of this time was a state of things still worse. A thousand years ago mercenary armies swarmed over Europe, while feudal predatory man was in disposition much like the sharks, crocodiles and tigers of the seas, rivers and jungles. It is difficult to imagine a period when we had no compass, engines, telescopes, barometers, thermometers, sciences of any sort, no gunpowder or firearms, or even soap and towels ; a time when no one knew how to read or write, for there was no alphabet. Ljng-haired and bearded pirates skirted the shores with their rude war-vessels, Vandals, Goths and Huns overran the continents and islands, armed with bows and spears. Still another step and man was a naked savage with the rudest of tools and weapons. And far enough back in the world's making there were no men or other animals, and even plants had a beginning.

A rough general statement of an early period of the earth's condition pictures a hot sea covering the globe, and, as the earth cooled and contracted, wrinkles in the shape of mountain chains thrust peaks miles above the sea surface, some of which made islands, while longer ranges skirted basins which later filled in by the washing down of the high mountains or rose from the sea as continents. Modern maps show coast-range rims to the larger bodies of land. The vapor from the hot sea at the base of the ranges rose high in the air and becoming condensed fell as rain and snow upon the peaks, packing into glaciers which during ages of gradual movement downward, together with the action of fierce storms and torrents from the melting ice, washed the mountain elevations down into the sea and formed the adjoining plains, though some of these expanses may also have risen from the ocean or have been created by the falling of the sea level. It is conceivable that at one time all there was of Europe, Asia, America and Africa consisted in such mountain chains, vastly higher than what remains of them, rising above the universal hot ocean. Between the sea level and highest elevations there were all the temperatures to be found between the tropics and the poles, and marine forms could find space and conditions favorable to evolution into the highest of land and air types in numberless such regions without recourse to migrations from long distances, though at later epochs such intermixtures occurred. My special contention is the sufficiency of many local environments to have developed species of many kinds within isolated regions and that all the different races of men have not sprung from a single source.

James Geikie 1 enumerates, in his chapter on the glacial succession in Europe, separate periods :

I. Preglacial Times. Genial climatic conditions indicated during the older pliocene system. The sea was over the east and south of England, in Belgium, Holland, northern and western France and the coast lands of the Mediterranean. The luxuriant plants of the land and the great mammals of the pliocene retreated gradually before the approaching winter of the glacial period, equatorial sea forms also retreated south and were replaced by arctic plants and animals.

II. First glacial epoch. A thoroughly arctic fauna lived in the North Sea, great snow fields came into existence and a gigantic glacier occupied the basin of the Baltic. The mountains of Britain were ice clad as were the Alps. In central France large glaciers descended from the volcanic cones of Auvergne and Coutal, and deployed upon the plateaux, and probably in many other districts similar conditions existed.

III. First interglacial epoch. The cold passed away, the arctic fauna retreated from the North Sea and dry land occupied the southern part of that sea up to the latitude of Norfolk at least. Across this new-formed land flowed the Rhine and other rivers. A temperate flora with hippopotami, elephants, deer and other mammals filled Europe and England. A luxuriant deciduous flora was in the Alps at heights it now no longer attains, with elephants, and this filled a long period.

IV. Second glacial epoch. The greatest of European ice sheets appeared covering all the northern part of the continent and flowed south into Saxony. The Alp glaciers reached their

1 The Great Ice Age, p. 607.

greatest extension and in other mountains of Europe snow fields and glaciers made their appearance. Arctic alpine plants came to occupy the low grounds of central Europe and northern annual plants ranged down to the shores of the Mediterranean.

V. Second interglacial epoch. Prolonged duration of the previous stage attested by moraines and then the climate became genial, northern flora retreated north and southern flora came north and southern mammals came up again. Then the climate deteriorated and the flora and fauna migrated again as the third glacial epoch approached. Much low lying land in northwestern and northern Europe was submerged. This interglacial period was of long duration.

VI. Third glacial epoch. At the climax of this epoch a most extensive ice sheet again overwhelmed the major portion of the British isles and a vast area of the continent, but it did not attain the dimensions of its predecessor. From the Alps great glaciers again descended to the low grounds, where they dropped the terminal moraines of the inner zone.

VII. Third interglacial epoch. After the disappearance of glacial conditions the Baltic became tenanted by a temperate North Sea fauna while the adjacent lands supported a corresponding terrestrial fauna and flora.

VIII. Fourth glacial epoch. In the early stages of this epoch the low grounds of Scotland were submerged to the extent of a hundred feet at least, while an arctic marine fauna lived around the coasts.

Eventually the various mountain districts were cased in ice and snow, large glaciers filled the highland fiords and sent icebergs to the sea, implying a snow line of 1,000 or 1,600 feet in .elevation. But the greatest ice was Baltic, an ice sheet covered Scandinavia and Finland, and an ice stream flowed from the Baltic basin to North Germany and Denmark ; later the ice sheet melted, a wide area of Scandinavia was submerged in a cold sea which communicated widely with the Baltic. In the Alps smaller glaciers than previously appeared and local glaciers were in the valleys of some of the mountain ranges of middle Europe.

IX. Fourth interglacial epoch. The British isles were part of the continent, the cold sea retreated from Scandinavia but the

Baltic became a lake, but later submergence again came, and the sea was filled with a more glacial climate fauna than at present.

X. Fifth glacial epoch. Moraines indicate a snow line of 2,500 feet in the British isles and submerged Scottish coast islands to 50 feet below the present level.

XL Fifth interglacial epoch. Land re-emerged and valley glaciers retreated. Northwest Europe drier and forest growths were abundant.

XII. Sixth glacial epoch. Snow line at 3,500 feet in Scotland and limited submergence of Scotland 20 or 30 feet. Forests decayed and peat bogs extended their area.

XIII. The present time in Britain is marked by the modern sea-level and return of a milder and drier condition and final disappearance of permanent snowfields.

Professor Frankland 2 says that a satisfactory theory must take cognizance of the following points in the history of the glacial period :

1. That its effects were felt over the entire globe. 2. That it occurred, or at least terminated, at a geologically recent period. 3. That it was preceded by a period of indefinite duration in which glacial action was altogether wanting or was confined to regions of considerable altitude. 4. That during its continuance atmospheric precipitation was much greater, and at one period the height of the snow line was considerably less than at present. 5. That it was followed by a period extending to the present time, when glacial action became again insignificant.

In order to secure a sufficient supply of ice to constitute a glacial epoch we must, in the first place, have an adequate amount of aqueous vapor in the atmosphere, and this could only arise from heated waters of the ocean, and Frankland concludes that a sole cause of the glacial epoch was a higher temperature of the ocean than that obtaining at present. I. That a higher oceanic temperature would give rise to an increased evaporation and consequently to an augmented atmospheric precipitation. 2. That this increased atmospheric precipitation would augment the

2 Philosophical Magazine, May, 1864, Quoted by Sir H. H. Hovvarth, Glacial Nightmare, Vol. 2, p. 23-

O THE EVOLUTION OF MAN AND HIS MIND.

average depth of permanent snow upon the ice bearers and would within certain limits depress the snow line.

James CrolP claims that Frankland was wrong in trying to account for phenomena of glacial action by terrestrial heat, as the glacial sea was cold and not hot. Of course it was, in the vicinity of the bergs, but while the lofty mountains made the glaciers the hot sea melted them. Dawson's fossil objections to Frankland's idea are also met by great heat and intermediate temperatures all the way to great cold to account for the fossils found. Frankland's hypothesis covers all the conditions and does away with the need of twisting the earth out of its position to account for only a portion of the facts while ignoring such as bear against so forced a conclusion. Howarth 4 admits that we should have traces of an arctic fauna and flora in the surface beds of the tropics, but they nowhere occur, and there is an absence of typical North American plants in the highlands of the West Indies and the Andes of the equator.

Taking Geikie's epochs, seriatim, Frankland's hot earth and sea explain them thus : I. The snow line was high with a temperate region on the mountain sides above the hot sea, but as the sea grew less hot the snow and ice line came lower and animals and plants moved southward. II. The receding of the sea would account for the ice advance, the land appearing by elevation from the sea with denudation of the hills as the earth shrank and piled up and filled in plains which became colder through distance from the hot sea. III. Mountains gradually denuded forming new lands in Europe with melting of glaciers toward the north and up the mountains. IV. Ice sheet over Europe and sea less hot and farther south while northern animals ranged down to the Mediterranean. V. Glaciers gradually melted by southern sun and terrestrial heat with temperate climate and later much land in upper Europe submerged by melting ice. VI. Another ice sheet covered Europe, but it was not so extensive as the first one. VII. Baltic and adjacent land filled with temperate fauna. VIII. Submergences from melting ice. Snow line 1,000 to 1,600 feet. IX. Temperate, warmer than at present, but sea not hot. X.

3 Climate and Cosmology, 1886.

4 Glacial Nightmare, p. 492.

Snow line 2,500 feet, so it was higher than in the preceding glacial epoch. Scottish coast lands under 50 feet of water, so the sea was less deep. XL Land re-emerged and forests grew and valley glaciers retreated. XII. Snow line 3,500 feet in Scotland anil land under 20 or 30 feet of water, forests decayed. XIII. The present, with snow fields retreated northward.

James Croll, of H. M. geological survey of Scotland 5 gives a theory of the secular changes of the earth's climate and quotes Morlot on two glacial periods separated by an intermediate one in which the ice that covered the greater part of Europe disappeared even in the principal valleys of the Alps to a height of 4,400 feet above the present level of the sea. Morlot thinks there may have been a cosmical cause : "Wild as it may have appeared when first started the idea of general and periodical eras of refrigeration for our planet connected perhaps with some cosmic agencv may eventually prove correct." 6

Croll 7 speaks of evidences of warm periods in the arctic region, fir trees having existed in latitude 74 ° 48', he cites from Sir William Hooper's report that the Pinus alba examined by him from the arctic regions consisted of alternate zones of narrow and broad growth as though the climate was hotter part of the year than at another. Probably the terrestrial heat with the solar was the most exuberant stage and corresponded to the summer, and the lesser heat afforded by the hot sea and ground alone for the balance of the year accounted for the smaller zone. Arctic regions were warm during the Permian period and there is a close resemblance of the Permian flora to that of the Carboniferous, pointing to a former prevalence of a warm and equable climate, and a warm sea must have been in high latitudes from the magnesium limestone there.

Frankland's hypothesis explains the stages Croll adopts : First mountains with glacial peaks and hot sea base in the polar regions and snow line high at the equator because of combined sun and earth heat. Second, formation of plains and subsidence of sea with less terrestrial heat than formerly but sufficient to

5 Climate and Time in Their Geological Relations. 8 Edinburg New Philos. Jour. Vol. II., p. 28. 7 Ibid., p. 261.

produce luxuriant vegetation and develop animals abundantly. The mountains lowering by washings with a corresponding rise of the glacial and snow eminences. Third, cooling of the earth and lowering of mountains by water and ice action could bring the ice sheets and glaciers farther south toward the Ohio and Mediterranean as they melt. Fourth, when the final melting took place the present epoch arrived.

Snow would lie higher up on mountains at the equator owing to the united effect of the perpendicular sun and the heat of the earth and sea, in ages before the earth was cooler. Proper regard for Frankland's idea would explain away the apparent inconsistency of the ice line going higher up the mountain as the earth cooled. The sea being less hot there would be vastly less vapor to condense, and not so much snow would fall, and as what was melted was not replaced the singular result would be that while great heat made deeper snow less heat brought less snow T , and as the earth grew cooler the snow peaks went higher.

Dana 8 gives the relative lengths of geological ages in their time ratios based on the maximum thicknesses of the rock formations and the rate of sedimentation and erosion. The whole duration of geological time he places at 200,000,000 years ; deducting for the Archean the rest of the time would be 130 million years. Reade gives 95 million, Walcott 70 million, Hutchison 600 million, McGee 6,000 million, and Kelvin 100 million. Dana sums up the results of speculation as between ten million and six thousand million years. The relative duration of the Cambrian and Silurian, the Devonian and Carboniferous correspond to the ratio of 4^ to 1 :i, or perhaps 4:1 :i, and for the Paleozoic, Mezozoic and Cenozoic 12:3:1. Since the glacial, Lyell, 31,000 years, Spencer 32,000 years. Reptiles appeared first in the Permian but their age was the Mezozoic. Mammals began then but their age was the Cenozoic. So man came in the Quaternary and possibly in the Tertiary, while the present is his age.

The Appalachian west of the Blue Range was the marginal bottom of the interior Palezoic sea. During the Carboniferous it was sometimes above or below the sea. The Sierra was the

"Manual of Geology, p. 1023.

first born of the Cordilleran Range, the marginal bottom line of the Pacific. The Alps during the Mesozoic and early Tertiary was the marginal sea bottom. At the end of the Eocene these were crushed together and folded upward. The Himalavas were similarly constructed.

A. H. Keane 9 regards the Tertiary as occupying 3 per cent of time; the Eocene with its mammals 1,250,000 years; the Miocene with higher apes 1,000,000 years; the Pliocene with man-like apes 850,000 years. Many geologists now believe the ice age Pliestocene of the Quaternary or Post Tertiary was more probably coincident with elevation rather than subsidence. The arctic and tropic fauna were mixed and men-like apes were already spread over the dry land of most of the world with palaeolithic man. The approximate beginning of the strictly Pliestocene or Quaternary times was 600,000 years ago, and the duration was about 530,000 years. The Post Pliocene or pre-historic time of neolithic man was scarcely less than 60,000 years and probably more largely coincides with the general disappearance of ice and appearance of men of the new stone age.

The historic or present age has been stated as proven to be 10,000 years and archaeological prospects promise to push this length of time much further backward.

Joseph Le Conte 10 in an article on Critical Periods in the History of the Earth says :

"Great and comparatively rapid changes in organic forms are produced in the following ways : I. The changes in physical geography open gateways and permit migrations in many directions. 2. The changes in climate compel migrations mainly north and south. 3. These migrations in their turn precipitate different faunas and floras upon one another, producing severe struggles between invaders and natives, and therefore the destruction of many forms of both, and large modifications of the survivors. 4. The foreign invasion compels many natives in their turn to migrate and so the wave of invasion, of severer struggle and of consequent changes is propagated as far as physical conditions will allow migration. The effect of all this must

* Ethnology, 1896, Ch. IV., Antiquity of Man.

10 Univ. of Cal. Bulletin of Dept. of Geology, Aug., 1895.

IO THE EVOLUTION OF MAN AND HIS MIND.

be a more rapid evolution of organic forms as the result (a) of a new environment and (b) of a severer struggle for life. The more rapid rate of evolution and especially new opportunities give rise to higher dominant classes. These higher dominant classes again in turn determine changes in lower forms, especially their immediate rivals, and these changes are again propagated downward through the whole organic kingdom and compel a new adjustment of the whole on a different basis."

Le Conte further holds that "the great theater of physical changes, of extensive migrations and of severe struggle and therefore of rapid evolution, especially of higher forms, and therefore also the place of first appearance of dominant classes has undoubtedly been what Huxley calls Arctogsea, i. e., those parts of North America and Eurasia that are north of the Himalayas and Sahara, or all the northern hemisphere north of Central America, Sahara and the Himalayas. This, the greatest body of contiguous land, has in later geological times been sometimes divided and ' sometimes united. It has been subject to the greatest changes, the widest migrations, the severest conflicts, and therefore the most rapid evolution of dominant forms. But these dominant forms have from time to time as opportunity offered invaded more southern lands and always as conquerers."