This etext was prepared by Sue Asscher asschers@dingoblue.net.au
from the etext prepared by Robert J. Robbins, PhD of the ESP Projecthttp://www.esp.org/rjr
THE VARIATION OF
ANIMALS AND PLANTS
UNDER DOMESTICATION
BY
CHARLES DARWIN, M.A., F.R.S., ETC.
IN TWO VOLUMES
VOLUME II.
CONTENTS.
CHAPTER 2.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 FERALANIMALS AND PLANTS—REVERSION IN CROSSED VARIETIES AND SPECIES—REVERSIONTHROUGH BUD-PROPAGATION, AND BY SEGMENTS IN THE SAME FLOWER OR FRUIT—INDIFFERENT PARTS OF THE BODY IN THE SAME ANIMAL—THE ACT OF CROSSING A DIRECTCAUSE OF REVERSION, VARIOUS CASES OF, WITH INSTINCTS—OTHER PROXIMATE CAUSESOF REVERSION—LATENT CHARACTERS—SECONDARY SEXUAL CHARACTERS—UNEQUALDEVELOPMENT OF THE TWO SIDES OF THE BODY—APPEARANCE WITH ADVANCING AGE OFCHARACTERS DERIVED FROM A CROSS—THE GERM, WITH ALL ITS LATENT CHARACTERS, AWONDERFUL OBJECT—MONSTROSITIES—PELORIC FLOWERS DUE IN SOME CASES TOREVERSION.
CHAPTER 2.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 CROSSEDBREEDS AND SPECIES; OFTEN STRONGER IN ONE SEX THAN THE OTHER; SOMETIMES DUE TOTHE SAME CHARACTER BEING PRESENT AND VISIBLE IN ONE BREED AND LATENT IN THEOTHER—INHERITANCE AS LIMITED BY SEX—NEWLY-ACQUIRED CHARACTERS IN OURDOMESTICATED ANIMALS OFTEN TRANSMITTED BY ONE SEX ALONE, SOMETIMES LOST BY ONESEX ALONE—INHERITANCE AT CORRESPONDING PERIODS OF LIFE—THE IMPORTANCE OF THEPRINCIPLE WITH RESPECT TO EMBRYOLOGY; AS EXHIBITED IN DOMESTICATED ANIMALS: ASEXHIBITED IN THE APPEARANCE AND DISAPPEARANCE OF INHERITED DISEASES; SOMETIMESSUPERVENING EARLIER IN THE CHILD THAN IN THE PARENT—SUMMARY OF THE THREEPRECEDING CHAPTERS.
CHAPTER 2.XV.—ON CROSSING.
FREE INTERCROSSING OBLITERATES THE DIFFERENCES BETWEEN ALLIED BREEDS—WHEN THENUMBERS OF TWO COMMINGLING BREEDS ARE UNEQUAL, ONE ABSORBS THE OTHER—THE RATEOF ABSORPTION DETERMINED BY PREPOTENCY OF TRANSMISSION, BY THE CONDITIONS OFLIFE, AND BY NATURAL SELECTION—ALL ORGANIC BEINGS OCCASIONALLY INTERCROSS;APPARENT EXCEPTIONS—ON CERTAIN CHARACTERS INCAPABLE OF FUSION; CHIEFLY OREXCLUSIVELY THOSE WHICH HAVE SUDDENLY APPEARED IN THE INDIVIDUAL—ON THEMODIFICATION OF OLD RACES, AND THE FORMATION OF NEW RACES BY CROSSING—SOMECROSSED RACES HAVE BRED TRUE FROM THEIR FIRST PRODUCTION—ON THE CROSSING OFDISTINCT SPECIES IN RELATION TO THE FORMATION OF DOMESTIC RACES.
CHAPTER 2.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—VARIOUSCAUSES WHICH KEEP VARIETIES DISTINCT, AS THE PERIOD OF BREEDING AND SEXUALPREFERENCE—VARIETIES OF WHEAT SAID TO BE STERILE WHEN CROSSED—VARIETIES OFMAIZE, VERBASCUM, HOLLYHOCK, GOURDS, MELONS, AND TOBACCO, RENDERED IN SOMEDEGREE MUTUALLY STERILE—DOMESTICATION ELIMINATES THE TENDENCY TO STERILITYNATURAL TO SPECIES WHEN CROSSED—ON THE INCREASED FERTILITY OF UNCROSSEDANIMALS AND PLANTS FROM DOMESTICATION AND CULTIVATION.