PLANTS UNDER DOMESTICATION, VOLUME II (OF 2)***


E-text prepared by Steven Gibbs, Keith Edkins, and the Project Gutenberg
Online Distributed Proofreading Team (http://www.pgdp.net)



Transcriber's note:

   A few typographical errors have been corrected: they are listed
   at the end of the text. The Errata on page viii, which were in
   the original book, have been applied to this e-text.

   Page numbers within curly brackets (such as {iii} and {27}
   have been included so that the reader might use the index.





THE VARIATION OF ANIMALS AND PLANTS UNDER DOMESTICATION.

by

CHARLES DARWIN, M.A., F.R.S., &c.

IN TWO VOLUMES.--VOL. II.

With Illustrations.







LONDON:
John Murray, Albemarle Street.
1868.

The right of Translation is reserved.

London: Printed by William Clowes and Sons, Stamford Street, and Charing
Cross.




{iii}

CONTENTS OF VOLUME II.

CHAPTER XII.

INHERITANCE.

WONDERFUL NATURE OF INHERITANCE--PEDIGREES OF OUR DOMESTICATED
ANIMALS--INHERITANCE NOT DUE TO CHANCE--TRIFLING CHARACTERS
INHERITED--DISEASES INHERITED--PECULIARITIES IN THE EYE INHERITED--DISEASES
IN THE HORSE--LONGEVITY AND VIGOUR--ASYMMETRICAL DEVIATIONS OF
STRUCTURE--POLYDACTYLISM AND REGROWTH OF SUPERNUMERARY DIGITS AFTER
AMPUTATION--CASES OF SEVERAL CHILDREN SIMILARLY AFFECTED FROM NON-AFFECTED
PARENTS--WEAK AND FLUCTUATING INHERITANCE: IN WEEPING TREES, IN DWARFNESS,
COLOUR OF FRUIT AND FLOWERS, COLOUR OF HORSES--NON-INHERITANCE IN CERTAIN
CASES--INHERITANCE OF STRUCTURE AND HABITS OVERBORNE BY HOSTILE CONDITIONS
OF LIFE, BY INCESSANTLY RECURRING VARIABILITY, AND BY REVERSION--CONCLUSION
... Page 1

CHAPTER XIII.

INHERITANCE _continued_--REVERSION OR ATAVISM.

DIFFERENT FORMS OF REVERSION--IN PURE OR UNCROSSED BREEDS, AS IN PIGEONS,
FOWLS, HORNLESS CATTLE AND SHEEP, IN CULTIVATED PLANTS--REVERSION IN FERAL
ANIMALS AND PLANTS--REVERSION IN CROSSED VARIETIES AND SPECIES--REVERSION
THROUGH BUD-PROPAGATION, AND BY SEGMENTS IN THE SAME FLOWER OR FRUIT--IN
DIFFERENT PARTS OF THE BODY IN THE SAME ANIMAL--THE ACT OF CROSSING A
DIRECT CAUSE OF REVERSION, VARIOUS CASES OF, WITH INSTINCTS--OTHER
PROXIMATE CAUSES OF REVERSION--LATENT CHARACTERS--SECONDARY SEXUAL
CHARACTERS--UNEQUAL DEVELOPMENT OF THE TWO SIDES OF THE BODY--APPEARANCE
WITH ADVANCING AGE OF CHARACTERS DERIVED FROM A CROSS--THE GERM WITH ALL
ITS LATENT CHARACTERS A WONDERFUL OBJECT--MONSTROSITIES--PELORIC FLOWERS
DUE IN SOME CASES TO REVERSION... Page 28

CHAPTER XIV.

INHERITANCE _continued_--FIXEDNESS OF CHARACTER--PREPOTENCY--SEXUAL
LIMITATION--CORRESPONDENCE OF AGE.

FIXEDNESS OF CHARACTER APPARENTLY NOT DUE TO ANTIQUITY OF
INHERITANCE--PREPOTENCY OF TRANSMISSION IN INDIVIDUALS OF THE SAME FAMILY,
IN CROSSED BREEDS AND SPECIES; OFTEN STRONGER IN ONE SEX THAN THE OTHER;
SOMETIMES DUE TO THE SAME CHARACTER BEING PRESENT AND VISIBLE IN ONE BREED
AND LATENT IN THE OTHER--INHERITANCE AS LIMITED BY SEX--NEWLY-ACQUIRED
CHARACTERS IN OUR DOMESTICATED ANIMALS OFTEN TRANSMITTED BY ONE SEX ALONE,
SOMETIMES LOST BY ONE SEX ALONE--INHERITANCE AT CORRESPONDING PERIODS OF
LIFE--THE IMPORTANCE OF THE PRINCIPLE WITH RESPECT TO EMBRYOLOGY; AS
EXHIBITED IN DOMESTICATED ANIMALS; AS EXHIBITED IN THE APPEARANCE AND
DISAPPEARANCE OF INHERITED DISEASES; SOMETIMES SUPERVENING EARLIER IN THE
CHILD THAN IN THE PARENT--SUMMARY OF THE THREE PRECEDING CHAPTERS... Page
62

{iv}

CHAPTER XV.

ON CROSSING.

FREE INTERCROSSING OBLITERATES THE DIFFERENCES BETWEEN ALLIED BREEDS--WHEN
THE NUMBERS OF TWO COMMINGLING BREEDS ARE UNEQUAL, ONE ABSORBS THE
OTHER--THE RATE OF ABSORPTION DETERMINED BY PREPOTENCY OF TRANSMISSION, BY
THE CONDITIONS OF LIFE, AND BY NATURAL SELECTION--ALL ORGANIC BEINGS
OCCASIONALLY INTERCROSS; APPARENT EXCEPTIONS--ON CERTAIN CHARACTERS
INCAPABLE OF FUSION; CHIEFLY OR EXCLUSIVELY THOSE WHICH HAVE SUDDENLY
APPEARED IN THE INDIVIDUAL--ON THE MODIFICATION OF OLD RACES, AND THE
FORMATION OF NEW RACES, BY CROSSING--SOME CROSSED RACES HAVE BRED TRUE FROM
THEIR FIRST PRODUCTION--ON THE CROSSING OF DISTINCT SPECIES IN RELATION TO
THE FORMATION OF DOMESTIC RACES... Page 85

CHAPTER XVI.

CAUSES WHICH INTERFERE WITH THE FREE CROSSING OF VARIETIES--INFLUENCE OF
DOMESTICATION ON FERTILITY.

DIFFICULTIES IN JUDGING OF THE FERTILITY OF VARIETIES WHEN CROSSED--VARIOUS
CAUSES WHICH KEEP VARIETIES DISTINCT, AS THE PERIOD OF BREEDING AND SEXUAL
PREFERENCE--VARIETIES OF WHEAT SAID TO BE STERILE WHEN CROSSED--VARIETIES
OF MAIZE, VERBASCUM, HOLLYHOCK, GOURDS, MELONS, AND TOBACCO, RENDERED IN
SOME DEGREE MUTUALLY STERILE--DOMESTICATION ELIMINATES THE TENDENCY TO
STERILITY NATURAL TO SPECIES WHEN CROSSED--ON THE INCREASED FERTILITY OF
UNCROSSED ANIMALS AND PLANTS FROM DOMESTICATION AND CULTIVATION... Page
100

CHAPTER XVII.

ON THE GOOD EFFECTS OF CROSSING, AND ON THE EVIL EFFECTS OF CLOSE
INTERBREEDING.

DEFINITION OF CLOSE INTERBREEDING--AUGMENTATION OF MORBID
TENDENCIES--GENERAL EVIDENCE ON THE GOOD EFFECTS DERIVED FROM CROSSING, AND
ON THE EVIL EFFECTS FROM CLOSE INTERBREEDING--CATTLE, CLOSELY INTERBRED;
HALF-WILD CATTLE LONG KEPT IN THE SAME
PARKS--SHEEP--FALLOW-DEER--DOGS--RABBITS--PIGS--MAN, ORIGIN OF HIS
ABHORRENCE OF INCESTUOUS MARRIAGES--FOWLS--PIGEONS--HIVE-BEES--PLANTS,
GENERAL CONSIDERATIONS ON THE BENEFITS DERIVED FROM CROSSING--MELONS,
FRUIT-TREES, PEAS, CABBAGES, WHEAT, AND FOREST-TREES--ON THE INCREASED SIZE
OF HYBRID PLANTS, NOT EXCLUSIVELY DUE TO THEIR STERILITY--ON CERTAIN PLANTS
WHICH EITHER NORMALLY OR ABNORMALLY ARE SELF-IMPOTENT, BUT ARE FERTILE,
BOTH ON THE MALE AND FEMALE SIDE, WHEN CROSSED WITH DISTINCT INDIVIDUALS
EITHER OF THE SAME OR ANOTHER SPECIES--CONCLUSION... Page 114

{v}

CHAPTER XVIII.

ON THE ADVANTAGES AND DISADVANTAGES OF CHANGED CONDITIONS OF LIFE:
STERILITY FROM VARIOUS CAUSES.

ON THE GOOD DERIVED FROM SLIGHT CHANGES IN THE CONDITIONS OF
LIFE--STERILITY FROM CHANGED CONDITIONS, IN ANIMALS, IN THEIR NATIVE
COUNTRY AND IN MENAGERIES--MAMMALS, BIRDS, AND INSECTS--LOSS OF SECONDARY
SEXUAL CHARACTERS AND OF INSTINCTS--CAUSES OF STERILITY--STERILITY OF
DOMESTICATED ANIMALS FROM CHANGED CONDITIONS--SEXUAL INCOMPATIBILITY OF
INDIVIDUAL ANIMALS--STERILITY OF PLANTS FROM CHANGED CONDITIONS OF
LIFE--CONTABESCENCE OF THE ANTHERS--MONSTROSITIES AS A CAUSE OF
STERILITY--DOUBLE FLOWERS--SEEDLESS FRUIT--STERILITY FROM THE EXCESSIVE
DEVELOPMENT OF THE ORGANS OF VEGETATION--FROM LONG-CONTINUED PROPAGATION BY
BUDS--INCIPIENT STERILITY THE PRIMARY CAUSE OF DOUBLE FLOWERS AND SEEDLESS
FRUIT... Page 145

CHAPTER XIX.

SUMMARY OF THE FOUR LAST CHAPTERS, WITH REMARKS ON HYBRIDISM.

ON THE EFFECTS OF CROSSING--THE INFLUENCE OF DOMESTICATION ON
FERTILITY--CLOSE INTERBREEDING--GOOD AND EVIL RESULTS FROM CHANGED
CONDITIONS OF LIFE--VARIETIES WHEN CROSSED NOT INVARIABLY FERTILE--ON THE
DIFFERENCE IN FERTILITY BETWEEN CROSSED SPECIES AND VARIETIES--CONCLUSIONS
WITH RESPECT TO HYBRIDISM--LIGHT THROWN ON HYBRIDISM BY THE ILLEGITIMATE
PROGENY OF DIMORPHIC AND TRIMORPHIC PLANTS--STERILITY OF CROSSED SPECIES
DUE TO DIFFERENCES CONFINED TO THE REPRODUCTIVE SYSTEM--NOT ACCUMULATED
THROUGH NATURAL SELECTION--REASONS WHY DOMESTIC VARIETIES ARE NOT MUTUALLY
STERILE--TOO MUCH STRESS HAS BEEN LAID ON THE DIFFERENCE IN FERTILITY
BETWEEN CROSSED SPECIES AND CROSSED VARIETIES--CONCLUSION... Page 173

CHAPTER XX.

SELECTION BY MAN.

SELECTION A DIFFICULT ART--METHODICAL, UNCONSCIOUS, AND NATURAL
SELECTION--RESULTS OF METHODICAL SELECTION--CARE TAKEN IN
SELECTION--SELECTION WITH PLANTS--SELECTION CARRIED ON BY THE ANCIENTS, AND
BY SEMI-CIVILISED PEOPLE--UNIMPORTANT CHARACTERS OFTEN ATTENDED
TO--UNCONSCIOUS SELECTION--AS CIRCUMSTANCES SLOWLY CHANGE, SO HAVE OUR
DOMESTICATED ANIMALS CHANGED THROUGH THE ACTION OF UNCONSCIOUS
SELECTION--INFLUENCE OF DIFFERENT BREEDERS ON THE SAME SUB