# The Principles of Biology Vol. I

THE PRINCIPLES OF BIOLOGY
BY
HERBERT SPENCER
IN TWO VOLUMES
VOLUME I
NEW YORK AND LONDON D. APPLETON AND COMPANY 1910
Copyright, 1866, 1898, By D. APPLETON AND COMPANY.
CONTENTS OF VOL. I.
PART I.—THE DATA OF BIOLOGY. :
| CHAPTER | PAGE | PAGE |
| I. | —Organic matter | 3 |
| II. | —The actions of forces on organic matter | 27 |
| III. | —The re-actions of organic matter on forces | 45 |
| III$^A$. | —Metabolism | 62 |
| IV. | —Proximate conception of life | 78 |
| V. | —The correspondence between life and its circumstances | 91 |
| VI. | —The degree of life varies as the degree of correspondence | 101 |
| VI$^A$. | —The dynamic element in life | 111 |
| VII. | —The scope of biology | 124 |
| PART II.—THE INDUCTIONS OF BIOLOGY. |||
| I. | —Growth | 135 |
| II. | —Development | 162 |
| II$^A$. | —Structure | 181 |
| III. | —Function | 197 |
| IV. | —Waste and repair | 213 |
| V. | —Adaptation | 227 |
| VI. | —Individuality | 244 |
| VI$^A$. | —Cell-life and cell-multiplication | 252 |
| VII. | —Genesis | 269 |
| VIII. | —Heredity | 301 |
| IX. | —Variation | 320 |
| X. | —Genesis, heredity, and variation | 336 |
| ​X$^A$. | —Genesis, heredity, and variation—Concluded | 356 |
| XI. | —Classification | 374 |
| XII. | —Distribution | 395 |
| PART III.—THE EVOLUTION OF LIFE. |||
| I. | —Preliminary | 415 |
| II. | —General aspects of the special-creation-hypothesis | 417 |
| III. | —General aspects of the evolution-hypothesis | 431 |
| IV. | —The arguments from classification | 441 |
| V. | —The arguments from embryology | 450 |
| VI. | —The arguments from morphology | 468 |
| VII. | —The arguments from distribution | 476 |
| VIII. | —How is organic evolution caused? | 490 |
| IX. | —External factors | 499 |
| X. | —Internal factors | 508 |
| XI. | —Direct equilibration | 519 |
| XII. | —Indirect equilibration | 529 |
| XIII. | —The co-operation of the factors | 549 |
| XIV. | —The convergence of the evidences | 554 |
| XIV$^A$. | —Recent criticisms and hypotheses | 559 |
| APPENDICES. |||
| A. | —The general law of animal fertility | 577 |
| B. | —The inadequacy of natural selection, etc. |
| | I. The inadequacy of natural selection | 602 |
| | II. Professor Weismann's theories | 633 |
| | III. A rejoinder to Professor Weismann | 651 |
| | IV. Weismannism once more | 671 |
| C. | —The inheritance of functionally-wrought modifications: a summary | 692 |
| D. | —On alleged "spontaneous generation" and on the hypothesis of physiological units | 696 |
PREFACE
TO THE REVISED AND ENLARGED EDITION.
Rapid in all directions, scientific progress has during the last generation been more rapid in the direction of Biology than in any other; and had this work been one dealing with Biology at large, the hope of bringing it up to date could not have been rationally entertained. But it is a work on the Principles of Biology; and to bring an exposition of these up to date, seemed not impossible with such small remnant of energy as is left me. Slowly, and often interrupted by ill-health, I have in the course of the last two years, completed this first volume of the final edition.
Numerous additions have proved needful. What was originally said about vital changes of matter has been supplemented by a chapter on "Metabolism." Under the title "The Dynamic Element in Life," I have added a chapter which renders less inadequate the conception of Life previously expressed. A gap in preceding editions, which should have been occupied by some pages on "Structure," is now filled up. Those astonishing actions in cell-nuclei which the microscope has of late revealed, will be found briefly set forth under the head of "Cell-Life and Cell-Multiplication." Further evidence and further thought have resulted in a supplementary chapter on "Genesis, Heredity, and Variation"; in which certain views ​enunciated in the first edition are qualified and developed. Various modern ideas are considered under the title "Recent Criticisms and Hypotheses." And the chapter on "The Arguments from Embryology" has been mainly rewritten. Smaller increments have taken the shape of new sections incorporated in pre-existing chapters. They are distinguished by the following section-marks:— § 8a, § 46a, § 87a, § 100a, § 113a, § 127a, §§ 130a- 130d. There should also be mentioned a number of foot-notes of some significance not present in preceding editions. Of the three additional appendices the two longer ones have already seen the light in other shapes.
After these chief changes have now to be named the changes necessitated by revision. In making them assistance has been needful. Though many of the amendments have resulted from further thought and inquiry, a much larger number have been consequent on criticisms received from gentlemen whose aid I have been fortunate enough to obtain: each of them having taken a division falling within the range of his special studies. The part concerned with Organic Chemistry and its derived subjects, has been looked through by Mr. W. H. Perkin, Ph.D., F.R.S., Professor of Organic Chemistry, Owens College, Manchester. Plant Morphology and Physiology have been overseen by Mr. A. G. Tansley, M.A., F.L.S., Assistant Professor of Botany, University College, London. Criticisms upon parts dealing with Animal Morphology, I owe to Mr. E. W. MacBride, M.A., Fellow of St. John's College, Cambridge, Professor of Zoology in the McGill University, Montreal, and Mr. J. T. Cunningham, M.A., late Fellow of University ​College, Oxford. And the statements included under Animal Physiology have been checked by Mr. W. B. Hardy, M.A., Fellow of Gonville and Caius College, Cambridge, Demonstrator of Physiology in the University. Where the discoveries made since 1864 have rendered it needful to change the text, either by omissions or qualifications or in some cases by additions, these gentlemen have furnished me with the requisite information.
Save in the case of the preliminary portion, bristling with the technicalities of Organic Chemistry (including the pages on "Metabolism"), I have not submitted the proofs, either of the new chapters or of the revised chapters, to the gentlemen above named. The abstention has resulted partly from reluctance to trespass on their time to a greater extent than was originally arranged, and partly from the desire to avoid complicating my own work. During the interval occupied in the preparation of this volume the printers have kept pace with me, and I have feared adding to the entailed attention the further attention which correspondence and discussion would have absorbed: feeling that it was better to risk minor inaccuracies than to leave the volume unfinished: an event which at one time appeared probable. I make this statement because, in its absence, one or other of these gentlemen might be held responsible for some error which is not his but mine.
Yet another explanation is called for. Beyond the exposition of those general truths constituting the Principles of Biology as commonly accepted, the original edition of this work contained sundry views for which biological opinion did not furnish any authority. Some of these have ​since obtained a certain currency; either in their original forms or in modified forms. Misinterpretations are likely to result. Readers who have met with them in other works may, in the absence of warning, suppose, to my disadvantage, that I have adopted them without acknowledgment. Hence it must be understood that where no indication to the contrary is given the substance is unchanged. Beyond the corrections which have been made in the original text, there are, in some cases, additions to the evidence or amplifications of the argument; but in all sections not marked as new, the essential ideas set forth are the same as they were in the original edition of 1864.
Brighton,
August, 1898.
PREFACE.
The aim of this work is to set forth the general truths of Biology, as illustrative of, and as interpreted by, the laws of Evolution: the special truths being introduced only so far as is needful for elucidation of the general truths.
For aid in executing it, I owe many thanks to Prof. Huxley and Dr. Hooker. They have supplied me with information where my own was deficient; and, in looking through the proof-sheets, have pointed out errors of detail into which I had fallen. By having kindly rendered me this valuable assistance, they must not, however, be held committed to any of the enunciated doctrines that are not among the recognized truths of Biology.
The successive instalments which compose this volume, were issued to the subscribers at the following dates:—No. 7 (pp. 1-80) in January, 1863; No. 8 (pp. 81-160) in April, 1863; No. 9 (pp. 161-240) in July, 1863; No. 10 (pp. 241-320) in January, 1864; No. 11 (pp. 321-400) in May, 1864; and No. 12 (pp. 401-476) in October, 1864.
This work was published before January 1, 1929, and is in the public domain worldwide because the author died at least 100 years ago.
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