CONTENTS.

  1. [On the Law which has regulated the introduction of New Species.] Pp. [1]-[25]
    1. [Geographical distribution dependent on Geologic Changes]
    2. [A Law deduced from well-known Geographical and Geological facts]
    3. [The form of a true system of Classification determined by this Law]
    4. [Geographical Distribution of Organisms]
    5. [Geological Distribution of the forms of Life]
    6. [High Organization of very ancient Animals consistent with this Law]
    7. [Objections to Forbes’ Theory of Polarity]
    8. [Rudimentary Organs]
    9. [Conclusion]
  2. [On the Tendency of Varieties to depart indefinitely from the Original Type.] Pp. [26]-[44]
    1. [Instability of Varieties supposed to prove the permanent distinctness of Species]
    2. [The Struggle for Existence]
    3. [The Law of Population of Species]
    4. [The Abundance or Rarity of a Species dependent upon its more or less perfect Adaptation to the Conditions of Existence]
    5. [Useful Variations will tend to Increase, useless or hurtful Variations to Diminish]
    6. [Superior Varieties will ultimately extirpate the Original Species]
    7. [The Partial Reversion of Domesticated Varieties explained]
    8. [Lamarck’s Hypothesis very different from that now advanced]
    9. [Conclusion]
  3. [Mimicry, and other Protective Resemblances among Animals.] Pp. [45]-[129]
    1. [Test of true and false Theories]
    2. [Importance of the Principle of Utility]
    3. [Popular Theories of Colour in Animals]
    4. [Importance of Concealment as influencing Colour]
    5. [Special modifications of Colour]
    6. [Theory of Protective Colouring]
    7. [Objection that Colour as being dangerous should not exist in Nature]
    8. [Mimicry]
    9. [Mimicry among Lepidoptera]
    10. [Lepidoptera mimicking other Insects]
    11. [Mimicry among Beetles]
    12. [Beetles mimicking other Insects]
    13. [Insects mimicking Species of other Orders]
    14. [Cases of Mimicry among the Vertebrata]
    15. [Mimicry among Snakes]
    16. [Mimicry among Birds]
    17. [Mimicry among Mammals]
    18. [Objections to Mr. Bates’ Theory of Mimicry]
    19. [Mimicry by Female Insects only]
    20. [Cause of the dull Colours of Female Birds]
    21. [Use of the gaudy Colours of many Caterpillars]
    22. [Summary]
    23. [General deductions as to Colour in Nature]
    24. [Conclusion]
  4. [The Malayan Papilionidæ, or Swallow-tailed Butterflies, as illustrative of the Theory of Natural Selection.] Pp. [130]-[200]
    1. [Special value of the Diurnal Lepidoptera for inquiries of this Nature]
    2. [Question of the rank of the Papilionidæ]
    3. [Distribution of the Papilionidæ]
    4. [Definition of the word Species]
    5. [Laws and Modes of Variation]
      1. [Simple Variability]
      2. [Polymorphism or Dimorphism]
      3. [Local form or variety]
      4. [Co-existing Variety]
      5. [Race or Subspecies]
      6. [Species]
    6. [Variation as specially influenced by Locality]
      1. [Local Variation of Size]
      2. [Local Variation of Form]
      3. [Local Variations of Colour]
    7. [Remarks on the facts of Local Variation]
    8. [Mimicry]
    9. [Concluding Remarks on Variation in Lepidoptera]
    10. [Arrangement and Geographical Distribution of the Malayan Papilionidæ]
      1. [Arrangement]
      2. [Geographical Distribution]
    11. [Range of the Groups of Malayan Papilionidæ]
    12. [Remarkable peculiarities of the island of Celebes]
    13. [Concluding Remarks]
  5. [On Instinct in Man and Animals.] Pp. [201]-[210]
    1. [How Instinct may be best Studied]
    2. [Definition of Instinct]
    3. [Does Man possess Instincts?]
    4. [How Indians travel through unknown and trackless Forests]
  6. [The Philosophy of Birds’ Nests.] Pp. [211]-[230]
    1. [Instinct or Reason in the Construction of Birds’ Nests]
    2. [Do Men build by Reason or by Imitation?]
    3. [Why does each Bird build a peculiar kind of Nest?]
    4. [How do young Birds learn to build their first Nest?]
    5. [Do Birds sing by Instinct or by Imitation?]
    6. [How young Birds may learn to build Nests.]
    7. [Man’s Works mainly Imitative]
    8. [Birds do Alter and Improve their Nests when altered conditions require it]
    9. [Conclusion]
  7. [A Theory of Birds’ Nests; showing the relation of certain differences of colour in female birds to their mode of nidification.] Pp. [231]-[263]
    1. [Changed Conditions and persistent Habits as influencing Nidification]
    2. [Classification of Nests]
    3. [Sexual differences of Colour in Birds]
    4. [The Law which connects the Colours of Female Birds with the mode of Nidification]
    5. [What the Facts Teach us]
    6. [Colour more variable than Structure or Habits, and therefore the Character which has generally been modified]
    7. [Exceptional cases confirmatory of the above Explanation]
    8. [Real or apparent exceptions to the Law stated at p.] [240]
    9. [Various modes of Protection of Animals]
    10. [Females of some groups require and obtain more Protection than the Males]
    11. [Conclusion]
  8. [Creation by Law.] Pp. [264]-[301]
    1. [Laws from which the Origin of Species may be deduced]
    2. [Mr. Darwin’s Metaphors liable to Misconception]
    3. [A case of Orchis-structure explained by Natural Selection]
    4. [Adaptation brought about by General Laws]
    5. [Beauty in Nature]
    6. [How new Forms are produced by Variation and Selection]
    7. [The Objection that there are Limits to Variation]
    8. [Objection to the argument from Classification]
    9. [The Times on Natural Selection]
    10. [Intermediate or generalized forms of Extinct Animals an indication of Transmutation or Development]
    11. [Conclusion]
    12. [A Demonstration of the Origin of Species]
  9. [The Development of Human Races under the Law of Natural Selection.] Pp. [302]-[331]
    1. [Wide difference of Opinion as to Man’s Origin]
    2. [Outline of the Theory of Natural Selection]
    3. [Different effects of Natural Selection on Animals and on Man]
    4. [Influence of External Nature in the development of the Human Mind]
    5. [Extinction of Lower Races]
    6. [The Origin of the Races of Man]
    7. [The Bearing of these views on the Antiquity of Man]
    8. [Their Bearing on the Dignity and Supremacy of Man]
    9. [Their Bearing on the future Development of Man]
    10. [Summary]
    11. [Conclusion]
  10. [The Limits of Natural Selection as applied to Man.] Pp. [333]-[371]
    1. [What Natural Selection can Not do]
    2. [The Brain of the Savage shown to be Larger than he Needs it to be]
      1. [Size of Brain an important Element of Mental Power]
      2. [Comparison of the Brains of Man and of Anthropoid Apes]
      3. [Range of intellectual power in Man]
      4. [Intellect of Savages and of Animals compared]
    3. [The use of the Hairy Covering of Mammalia]
    4. [The Constant absence of Hair from certain parts of Man’s body a remarkable Phenomenon]
    5. [Savage Man feels the want of this Hairy Covering]
    6. [Man’s Naked Skin could not have been produced by Natural Selection]
    7. [Feet and Hands of Man considered as Difficulties on the Theory of Natural Selection]
    8. [The Origin of Some of Man’s Mental Faculties, by the preservation of Useful Variations, not possible]
    9. [Difficulty as to the Origin of the Moral Sense]
    10. [Summary of the Argument as to the Insufficiency of Natural Selection to account for the Development of Man]
    11. [The Origin of Consciousness]
    12. [The Nature of Matter]
      1. [Matter is Force]
      2. [All Force is probably Will-force]
    13. [Conclusion]

I.
ON THE LAW WHICH HAS REGULATED THE INTRODUCTION OF NEW SPECIES.[A]

Geographical Distribution dependent on Geologic Changes.

Every naturalist who has directed his attention to the subject of the geographical distribution of animals and plants, must have been interested in the singular facts which it presents. Many of these facts are quite different from what would have been anticipated, and have hitherto been considered as highly curious, but quite inexplicable. None of the explanations attempted from the time of Linnæus are now considered at all satisfactory; none of them have given a cause sufficient to account for the facts known at the time, or comprehensive enough to include all the new facts which have since been, and are daily being added. Of late years, however, a great light has been thrown upon the subject by geological investigations, which have shown that the present state of the earth and of the organisms now inhabiting it, is but the last stage of a long and uninterrupted series of changes which it has undergone, and consequently, that to endeavour to explain and account for its present condition without any reference to those changes (as has frequently been done) must lead to very imperfect and erroneous conclusions.

The facts proved by geology are briefly these:—That during an immense, but unknown period, the surface of the earth has undergone successive changes; land has sunk beneath the ocean, while fresh land has risen up from it; mountain chains have been elevated; islands have been formed into continents, and continents submerged till they have become islands; and these changes have taken place, not once merely, but perhaps hundreds, perhaps thousands of times:—That all these operations have been more or less continuous, but unequal in their progress, and during the whole series the organic life of the earth has undergone a corresponding alteration. This alteration also has been gradual, but complete; after a certain interval not a single species existing which had lived at the commencement of the period. This complete renewal of the forms of life also appears to have occurred several times:—That from the last of the geological epochs to the present or historical epoch, the change of organic life has been gradual: the first appearance of animals now existing can in many cases be traced, their numbers gradually increasing in the more recent formations, while other species continually die out and disappear, so that the present condition of the organic world is clearly derived by a natural process of gradual extinction and creation of species from that of the latest geological periods. We may therefore safely infer a like gradation and natural sequence from one geological epoch to another.

Now, taking this as a fair statement of the results of geological inquiry, we see that the present geographical distribution of life upon the earth must be the result of all the previous changes, both of the surface of the earth itself and of its inhabitants. Many causes, no doubt, have operated of which we must ever remain in ignorance, and we may, therefore, expect to find many details very difficult of explanation, and in attempting to give one, must allow ourselves to call into our service geological changes which it is highly probable may have occurred, though we have no direct evidence of their individual operation.

The great increase of our knowledge within the last twenty years, both of the present and past history of the organic world, has accumulated a body of facts which should afford a sufficient foundation for a comprehensive law embracing and explaining them all, and giving a direction to new researches. It is about ten years since the idea of such a law suggested itself to the writer of this essay, and he has since taken every opportunity of testing it by all the newly-ascertained facts with which he has become acquainted, or has been able to observe himself. These have all served to convince him of the correctness of his hypothesis. Fully to enter into such a subject would occupy much space, and it is only in consequence of some views having been lately promulgated, he believes, in a wrong direction, that he now ventures to present his ideas to the public, with only such obvious illustrations of the arguments and results as occur to him in a place far removed from all means of reference and exact information.