Part 4

330 Concluding paragraph rewritten.

London, March, 1870.

PREFACE TO THE SECOND EDITION.

The flattering reception of my Essays by the public and the press having led to a second edition being called for within a year of its first publication, I have taken the opportunity to make a few necessary corrections. I have also added a few passages to the 6th and 7th Essays, and have given two notes, explanatory of some portions of the last chapter which appear to have been not always understood. These additions are as follows:--

+-------------------------------------------------------------------+ | To avoid altering the paging the additional pages now given have | | been lettered. | +---------+---------+-----------------------------------------------+ | 1st Ed. | 2nd Ed. | | +---------+---------+ | | 221 | 221 | Additional facts as to birds acquiring | | | | the song of other species. | | | | | | 223 | 223A } | Mr. Spruce's remarks on young birds | | | 223B } | pairing with old. | | | | | | 228 | 228A } | Pouchet's observations on a change | | | 228B } | in the nests of swallows. | | | | | | 229 | -- | Passage omitted about nest of Golden | | | | Crested Warbler, which had been | | | | inserted on Rennie's authority, but | | | | has not been confirmed by any later | | | | observers. | | | | | | 261 | 261 | Daines Barrington, on importance of | | | | protection to the female bird. | | | | | | | 372 | Note A. | | | | | | | 372B | Note B. | +---------+---------+-----------------------------------------------+

CONTENTS.

I.--On the Law which has regulated the introduction of New Species. Pp. 1-25

Geographical distribution dependent on Geologic Changes

A Law deduced from well-known Geographical and Geological facts

The form of a true system of Classification determined by this Law

Geographical Distribution of Organisms

Geological Distribution of the forms of Life

High Organization of very ancient Animals consistent with this Law

Objections to Forbes' Theory of Polarity

Rudimentary Organs

Conclusion

II.--On the Tendency of Varieties to depart indefinitely from the Original Type. Pp. 26-44

Instability of Varieties supposed to prove the permanent distinctness of Species

The Struggle for Existence

The Law of Population of Species

The Abundance or Rarity of a Species dependent upon its more or less perfect Adaptation to the Conditions of Existence

Useful Variations will tend to Increase, useless or hurtful Variations to Diminish

Superior Varieties will ultimately extirpate the Original Species

The Partial Reversion of Domesticated Varieties explained

Lamarck's Hypothesis very different from that now advanced

Conclusion

III.--Mimicry, and other Protective Resemblances among Animals. Pp. 45-129

Test of true and false Theories