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1 I

THE VARIATION

OF

ANIMALS AND PLANTS

UNDER DOMESTICATION.

BY

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

AUTHORIZED EDITION, "WITH A PREFACE

BY
PROFESSOR ASA G>RAY.

IN TWO VOLUMES. VOL. II.

SHUjj Illustrations.

NEW-YORK: .
ORANGE JUDD & COMPANY,
245 BROADWAY.

Entered, according to Act of Congress, in the year 1S6S, by

ORANGE JUDD & COMPANY,

In the Clerk's Office of the District Court of the United States for the Southern
District of New- York.

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 ETE INHER-
ITED DISEASES IN THE HORSE LONGEVITY AND VIGOUR ASYM-
METRICAL 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 OVER-
BORNE BY HOSTILE CONDITIONS OF LIFE, BY INCESSANTLY RECURRING
VARIABILITY AND BY REVERSION CONCLUSION Pa^e 9

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 DE-
RIVED FROM A CROSS THE GERM WITH ALL ITS LATENT CHARACTERS

A WONDERFUL OBJECT MONSTROSITIES PELORIC FLOWERS DUE IN

SOME CASES TO REVERSION 41

IV CONTENTS OF VOL. II.

CHAPTER XIV.

INHERITANCE continual— FIXEDNESS OF CHARACTER — PRE-
POTENCY — SEXUAL LIMITATION — CORRESPONDENCE OF
AGE.

FIXEDNESS OF CHARACTER APPARENTLY NOT DUE TO ANTIQUITY OF IN-
HERITANCE 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 EX-
HIBITED IN THE APPEARANCE AND DISAPPEARANCE OF INHERITED DIS-
EASES ; SOMETIMES SUPERVENING EARLIER IN THE CHILD THAN IN THE
PARENT SUMMARY OF THE THREE PRECEDING CHAPTERS .. Page 81

CHAPTER XV.

ON CROSSING.

FREE INTERCROSSING OBLITERATES THE DIFFERENCES BETWEEN ALLIED
BREEDS WHEN THE NUMBERS OF TWO COMMINGLING BREEDS ARE UN-
EQUAL, ONE ABSORBS THE OTHER THE RATE OF ABSORPTION DETER-
MINED BY PREPOTENCY OF TRANSMISSION, BY THE CONDITIONS OF LIFE,

AND BY NATURAL SELECTION ALL ORGANIC BEINGS OCCASIONALLY

INTERCROSS J APPARENT EXCEPTIONS ON CERTAIN CHARACTERS INCAPA-
BLE 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 108

CHAPTER XVI.

CAUSES WHICH INTERFERE WITH THE FREE CROSSING OF
VARIETIES — INFLUENCE OF DOMESTICATION ON FERTIL-
ITY.

DIFFICULTIES IN JUDGING OF TnE FERTILITY OF VARIETIES WHEN CROSSED
— VARIOUS CAUSES WHICH KEEP VARIETIES DISTINCT, AS THE PERIOD

OF BREEDING AND SEXUAL PREFERENCE VARIETIES OF WHEAT SAID TO

BK STERILE WHEN CROSSED VARIETIES OF MAIZE, VERBASCCM, HOL-
LYHOCK, GOURDS, MELONS, AND TOBACCO, RENDERED IN SOME DEGREE

CONTENTS OF VOL. II.

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 PagCl2(5

CHAPTER XVII.

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

DEFINITION OF CLOSE INTERBREEDING AUGMENTATION OF MORBID TEN-
DENCIES 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 BENE-
FITS 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 CROSS-
ED WITH DISTINCT INDIVIDUALS EITHER OF THE SAME OR ANOTHER
SPECIES CONCLUSION 142

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 OP
LIFE — STERILITY FROM CHANGED CONDITIONS, IN ANIMALS, IN THEIR
NATIVE COUNTRY AND IN MENAGERIES — MAMMALS, BIRDS, AND IN-
SECTS LOSS OF SECONDARY SEXUAL CHARACTERS AND OF INSTINCTS —

CAUSES OF STERILITY STERILITY OF DOMESTICATED ANIMALS FROM

CHANGED CONDITIONS SEXUAL INCOMPATIBILITY OF INDIVIDUAL ANI-
MALS 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 PRIMA-
RY CAUSE OF DOUBLE FLOWERS AND SEEDLESS FRUIT 178

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

VI CONTENTS OF VOL. II.

CHANGED CONDITIONS OF LIFE VARIETIES WHEN CROSSED NOT INVA-
RIABLY 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 DOMES-
TIC VARIETIES ARE NOT MUTUALLY STERILE TOO MUCH STRESS HAS

BEEN LAID ON THE DIFFERENCE IN FERTILITY BETWEEN CROSSED SPECIES
AND CROSSED VARIETIES — CONCLUSION Page 211

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 CHA-
RACTERS OFTEN ATTENDED TO UNCONSCIOUS SELECTION AS CIRCUM-
STANCES SLOWLY CHANGE, SO HAVE OUR DOMESTICATED ANIMALS CHANGED
THROUGH THE ACTION OF UNCONSCIOUS SELECTION INFLUENCE OF DIF-
FERENT BREEDERS ON THE SAME SUB- VARIETY PLANTS AS AFFECTED

BY UNCONSCIOUS SELECTION EFFECTS OF SELECTION AS SHOWN BY

THE GREAT AMOUNT OF DIFFERENCE IN THE PARTS MOST VALUED BY
MAN 233

CHAPTER XXI.
SELECTION— continued.

NATURAL SELECTION AS AFFECTING DOMESTIC PRODUCTIONS CHARACTERS

WHICH APPEAR OF TRIFLING VALUE OFTEN OF REAL IMPORTANCE

CIRCUMSTANCES FAVOURABLE TO SELECTION BY MAN FACILITY IN PRE-
VENTING CROSSES, AND THE NATURE OF THE CONDITIONS CLOSE AT-
TENTION AND PERSEVERANCE INDISPENSABLE THE PRODUCTION OF A

LARGE NUMBER OF INDIVIDUALS ESPECIALLY FAVOURABLE WHEN NO

SELECTION IS APPLIED, DISTINCT RACES ARE NOT FORMED HIGHLY-
BRED ANIMALS LIABLE, TO DEGENERATION TENDENCY IN MAN TO CARRY

THE SELECTION OF EACH CHARACTER TO AN EXTREME POINT, LEADING

TO DIVERGENCE OF CHARACTER, RARELY TO CONVERGENCE CHARACTERS

CONTINUING TO VARY IN THE SAME DIRECTION IN WHICH THEY HAVE

ALREADY VARIED DIVERGENCE OF CHARACTER, WITH THE EXTINCTION

OF INTERMEDIATE VARIETIES, LEADS TO DISTINCTNESS IN OUR DOMESTIC
RACES LIMIT TO THE POWER OF SELECTION LAPSE OF TIME IM-
PORTANT MANNER IN WHICH DOMESTIC RACES HAVE ORIGINATED

SUMMARY 271

CONTENTS OF VOL. II. Vll

CHAPTER XXII.

CAUSES OF VARIABILITY.

VARIABILITY DOES NOT NECESSARILY ACCOMPANY REPRODUCTION CACSE8

ASSIGNED BY VARIOUS AUTHORS INDIVIDUAL DIFFERENCES VARI-
ABILITY OF EVERY KIND DUE TO CHANGED CONDITIONS OF LIFE ON

THE NATURE OF SUCH CHANGES CLIMATE, FOOD, EXCESS OF NUTRI-
MENT SLIGHT CHANGES SUFFICIENT EFFECTS OF GRAFTING ON THE

VARIABILITY OF SEEDLING-TREES DOMESTIC PRODUCTIONS BECOME HA-
BITUATED TO CHANGED CONDITIONS ON THE ACCUMULATIVE ACTION

OF CHANGED CONDITIONS CLOSE INTERBREEDING AND THE IMAGINA-
TION OF THE MOTHER SUPPOSED TO CAUSE VARIABILITY CROSSING AS

A CAUSE OF THE APPEARANCE OF NEW CHARACTERS VARIABILITY

FROM THE COMMINGLING OF CHARACTERS AND FROM REVERSION ON

THE MANNER AND PERIOD OF ACTION OF THE CAUSES WHICH EITHER
DIRECTLY, OR INDIRECTLY THROUGH THE REPRODUCTIVE SYSTEM, INDUCE

variability Page 302

CHAPTER XXIII.

DIRECT AND DEFINITE ACTION OF THE EXTERNAL CON-
DITIONS OF LIFE.'

SLIGHT MODIFICATIONS' IN PLANTS FROM THE DEFINITE ACTION OF CHANGED
CONDITIONS, IN SIZE, COLOUR, CHEMICAL PROPERTIES, AND IN THE
STATE OF THE TISSUES LOCAL DISEASES CONSPICUOUS MODIFICA-
TIONS FROM CHANGED CLIMATE OR FOOD, ETC. PLUMAGE OF BIRDS AF-
FECTED BY PECULIAR NUTRIMENT, AND BY THE INOCULATION OF POISON

LAND-SHELLS MODIFICATIONS OF ORGANIC BEINGS IN A STATE OF

NATURE THROUGH THE DEFINITE ACTION OF EXTERNAL CONDITIONS

COMPARISON OF AMERICAN AND EUROPEAN TREES GALLS EFFECTS

OF PARASITIC FUNGI CONSIDERATIONS OPPOSED TO THE BELIEF IN

THE POTENT INFLUENCE OF CHANGED EXTERNAL CONDITIONS PARAL-
LEL SERIES OF VARIETIES AMOUNT OF ■ VARIATION DOES NOT CORRES-
POND WITH THE DEGREE OF CHANGE IN THE CONDITIONS BUD-VARIATION

MONSTROSITIES PRODUCED BY UNNATURAL TREATMENT SUMMARY 327

CHAPTER XXIV.

LAWS OF VARIATION — USE AND DISUSE, ETC.

NISUS FORMATIVUS, OR THE CO-ORDINATING POWER OF THE ORGANIZATION

ON THE EFFECTS OF THE INCREASED USE AND DISUSE OF ORGANS

CHANGED HABITS OF LIFE ACCLIMATISATION WITH ANIMALS AND

PLANTS — VARIOUS METHODS BY WHICH THIS CAN BE EFFECTED

ARRESTS OF DEVELOPMENT RUDIMENTARY ORGANS 353

CHAPTER XXV.

LAWS OF VARIATION, continued— CORRELATED VARIABILITY.

EXPLANATION OF TERM CORRELATION AS CONNECTED WITH DEVELOPMENT

Vlll CONTENTS OF VOL. II.

MODIFICATIONS CORRELATED WITH THE INCREASED OR DECREASED

SIZE OF PARTS CORRELATED VARIATION OF HOMOLOGOUS PARTS

FEATHERED FEET IN BIRDS ASSUMING THE STRUCTURE OF THE WINGS
CORRELATION BETWEEN THE HEAD AND THE EXTREMITIES BE-
TWEEN THE SKIN AND DERMAL APPENDAGES BETWEEN THE ORGANS

OF SIGHT AND HEARING CORRELATED MODIFICATIONS IN THE ORGANS

OF PLANTS CORRELATED MONSTROSITIES CORRELATION BETWEEN THE

SKULL AND EARS SKULL AND CREST OF FEATHERS SKULL AND

HORNS CORRELATION OF GROWTH COMPLICATED BY THE ACCUMULATED

EFFECTS OF NATURAL SELECTION COLOUR AS CORRELATED WITH CON-
STITUTIONAL peculiarities Paste 384

CHAPTER XXVI.

LAWS OF VARIATION, continued — SUMMARY.

ON THE AFFINITY AND COHESION OF HOMOLOGOUS PARTS ON THE VARI-
ABILITY OF MULTIPLE AND HOMOLOGOUS PARTS COMPENSATION OF

GROWTH MECHANICAL PRESSURE RELATIVE POSITION OF FLOWERS

WITH RESPECT TO THE AXIS OF THE PLANT, AND OF SEEDS IN THE CAP-
SULE, AS INDUCING VARIATION ANALOGOUS OR PARALLEL VARIETIES

SUMMARY OF THE THREE LAST CHAPTERS 407

CHAPTER XXVII.

PROVISIONAL HYPOTHESIS OF PANGENESIS.

PRELIMINARY REMARKS FIRST PART I THE FACTS TO BE CONNECTED

UNDER. A SINGLE POINT OF VIEW, NAMELY, THE VARIOUS KINDS OF

REPRODUCTION THE DIRECT ACTION OF THE MALE ELEMENT ON THE

FEMALE DEVELOPMENT THE FUNCTIONAL INDEPENDENCE OF THE

ELEMENTS OR UNITS OF THE BODY VARIABILITY INHERITANCE

REVERSION.

SECOND PART : STATEMENT OF THE HYPOTHESIS HOW FAR THE NECES-
SARY ASSUMPTIONS ARE IMPROBABLE EXPLANATION BY AID OF THE

HYPOTHESIS OF THE SEVERAL CLASSES OF FACTS SPECIFIED IN THE
FIRST PART CONCLUSION 428

CHAPTER XXVIII.

CONCLUDING REMARKS.

domestication nature and causes of variability selection

divergence and distinctness of character extinction of races

circumstances favourable to selection by man antiquity of

certain races the question whether each particular variation

has been specially preordained 484

Index ; 517

THE

VARIATION OF ANIMALS AND PLANTS

UNDER DOMESTICATION.

CHAPTER XII.

INHERITANCE.

WONDERFUL NATURE OF INHERITANCE — PEDIGREES OF OUR DOMES-
TICATED ANIMALS — INHERITANCE NOT DUE TO CHANCE — TRI-
FLING CHARACTERS INHERITED — DISEASES INHERITED — PECULIA-
RITIES IN THE EYE INHERITED — DISEASES IN THE HORSE — LON-
GEVITY AND VIGOUR — ASYMMETRICAL DEVIATIONS OF STRUCTURE
— POLYDACTYLISM AND REGROWTH OF SUPERNUMERARY DIGITS
AFTER AMPUTATION — CASES OF SEVERAL CHILDREN SIMILARLY
AFFECTED FROM NON- AFFECTED PARENTS — WE*AK AND FLUCTUAT-
ING 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.

The subject of inheritance is an immense one, and has been
treated by man)- authors. One work alone, 'De ITIere-
ditc Xaturelle,' by Dr. Prosper Lucas, runs to the length of
1562 pages. We must confine ourselves to certain points
which have an important bearing on the general subject
of variation, both with domestic and natural productions.
It is obvious that a variation which is not inherited
throws no light on the derivation of species, nor is of any
service to man, except in the case of perennial plants,
which can be propagated by buds.

10 INHERITANCE. Chap. XII.

If animals and plants had never been domesticated, and
wild ones alone had been observed, we should probably
never have heard the saying, that " like begets like."
The proposition would have been as self-evident, as that
all the buds on the same tree are alike, though neither
proposition is strictly true. For, as has often been re-
marked, probably no two individuals are identically the
same. All wild animals recognise each other, which
shows that there is some difference between them ; and
when the eye is well practised, the shepherd knows each
sheep, and man can distinguish a fellow-man out of mil-
lions on millions of other men. Some authors have gone
so far as to maintain that the production of slight differ-
ences is as much a necessary function of the powers of
generation, as the production of offspring like their
parents. This view, as we shall see in a future chapter,
is not theoretically probable, though practically it holds
good. The saying that " like begets like " has in fact
arisen from the perfect confidence felt by breeders, that a
superior or inferior animal will generally reproduce its
kind ; but this very superiority or inferiority shows that
the individual in question has departed slightly from its
type.

The whole subject of inheritance is wonderful. When
a new character arises, whatever its nature maybe, it gen-
erally tends to be inherited, at least in a temporary and
sometimes in a most persistent manner. What can be
more wonderful than that some trifling peculiarity, not
primordially attached %o the species, should be transmit-
ted through the male or female sexual cells, which are so
minute as not to be visible to the naked eye, and after-
wards through the incessant changes of a long course of
development, undergone either in the womb or in the egg,
and ultimately appear in the offspring when mature, or
even when quite old, as in the case of certain diseases ?
Or again, what can be more wonderful than the well-as-
certained fact that the minute ovule of a good milkino;

Chap. XII. INHERITANCE. 1 1

cow will produce a male, from whom a cell, in union with
an ovule, will produce a female, and she, when mature,
will have large mammary glands, yielding an abundant
supply of milk, and even milk of a particular quality?
Nevertheless, the real subject of surprise is, as Sir H.
Holland has well remarked,1 not that a character should
be Inherited, but that any should ever fail to be inherited.
In a future chapter, devoted to an hypothesis which I
have termed pangenesis, an attempt will be made to show
the means by which characters of all kinds are transmitted
from generation to generation.

Some writers,2 who have not attended to natural history,
have attempted to show that the force of inheritance
has been much exaggerated. The breeders of animals
would smile at such simplicity ; and if they condescended
to make any answer, might ask what would be the chance
of winning a prize if two inferior animals were paired to-
gether? They might ask whether the half-wild Arabs
were led by theoretical notions to keep pedigrees of their
horses ? Why have pedigrees been scrupulously kept and
published of the Shorthorn cattle, and more recently of
the Hereford breed ? Is it an illusion that these recent-
ly improved animals safely transmit their excellent quali-
ties even when crossed with other breeds? have the
Shorthorns, without good reason, been purchased at im-
mense prices and exported to almost every quarter of the
globe, a thousand guineas having been given for a bull ?
With greyhounds pedigrees have likewise been kept, and
the names of such dogs, as Snowball, Major, &c., are as
well known to coursers as those of Eclipse and Herod on
the turf. Even with the Game-cock pedigrees of famous
strains were formerly kept, and extended back for a cen-
tury. With pigs, the Yorkshire and Cumberland breed-

1 ' Medical Notes and Reflections,' 3rd subject, owing to the want of statistics,

edit., 1S55, p. 267. See also Mr. Bowen, Professor of Mora)

3 Mr. Buckle, in his grand work on Philosophy, In ' Proc. American Acad.

' Civilisation,' expresses doubts on the of Sciences,' vol. v. p. 102.

12 INHERITANCE. Chap. XII.

ers " pi'eserve and print pedigrees ;" and to show how
such highly-bred animals are valued, I may mention that
Mr. Brown, who won all the first prizes for small breeds
at Birmingham in 1850, sold a young sow and boar of his
breed to Lord Ducie for 43 guineas ; the sow alone was af-
terwards sold to the Rev. F. Thursby for 65 guineas ; who
writes, " she paid me very well, having sold her produce
for 3007., and having now four breeding sows from her."3
Hard cash paid down, over and over again, is an excellent
test of inherited superiority. In fact, the whole art of
breeding, from which such great results have been at-
tained during the present century, depends on the inheri-
tance of each small detail of structure. But inheritance
is not oertain ; for if it were, the breeder's art4 would be
reduced to a certainty, and there would be little scope left
for all that skill and perseverance shown by the men who
have left an enduring monument of their success in the
present state of our domesticated animals.

It is hardly possible, within a moderate compass, to
impress on the mind of those who have not attended to
the subject, the full conviction of the force of inheritance
which is slowly acquired by rearing animals, by studying
the many treatises which have been published on the
various domestic animals, and by conversing with breed-
ers. I will select a few facts of the kind, which, as far
as I can judge, have most influenced my own mind.
With man and- the domestic animals, certain peculiarities
have appeared in an individual, at rare intervals, or only
once or twice in the history of the world, but have reap-
peared in several of the children and grandchildren.
Thus Lambert, "the porcupine-man," whose skin was
thickly covered with warty projections, which were pe-
riodically moulted, had all his six children and two grand-

3 For greyhounds, see Low's ' Domest. For pigs, see Mr. Sidney's edit, of ' You-

Animals of the British Islands,' 1845, p. att on the Pig,' 1SG0, pp. 11, 22. .

721. For game-fowls, eee ' The Poultry * ' The Stud Farm,' by Cecil, p. 39.
Book,' by Mr. Tegetmeier, 1S66, p. 123.

Chap. XII. INHERITANCE. 13

sons similarly affected.* The face and body being cover-
ed with long hair, accompanied by deficient teeth (to
.which I shall hereafter refer), occurred in three successive
generations in a Siamese family; but this case is not
unique, as a woman6 with a completely hairy face Mas
exhibited in London in 1663, and another instance has
recently occurred. Colonel Hallam7 has described a race
of two-legged pigs, " the hinder extremities being entirely
wanting;" and this deficiency was transmitted through
three generations. In fact, all races presenting any re-
markable peculiarity, such as solid-hoofed swine; Mau-
champ sheep, niata cattle, &c, are instances of the long-
continued inheritance of rare deviations of structure.

When we reflect that certain extraordinary peculiari-
ties have thus appeared in a single individual out of many
millions, all exposed in the same country to the same
general conditions of life, and, again, that the same extra-
ordinary peculiarity has sometimes appeared in individu-
als living under widely different conditions of life, we are
driven to conclude that such peculiarities are not directly
due to the action of the surrounding conditions, but to
unknown laws acting on the organisation or constitution
of the individual ; — that their production stands in hardly
closer relation to the conditions than does life itself. If
this be so, and the occurrence of the same unusual char-
acter in the child and parent cannot be attributed to both
having been exposed to the same unusual conditions, then
the following problem is worth consideration, as showing
that the result cannot be due, as some authors have sup-
posed, to mere coincidence, but must be consequent on
the members of the same family inheriting something in

6 'Philosophical Transactions,' 1T55, * Barbara Van Beck, figured, as I am

p. 23. I have seen only second-hand ac- informed by the Bev. W. D. Fox, in

counts of the two grandsons. Mr. Sedg- Woodburn's ' Gallery of Bare Portraits.'

wick, in a paper to which I shall here- 1816, vol. ii.

after often refer, states that four gen- 7 ' Proc. Zoolog. Soc.,' 1833, p. 16.
erations were affected, and in each the
males alone.

14 INHERITANCE. Chap. XII.

common in their constitution. Let it be assumed that, in
a large population, a particular affection occurs on an
average in one out of a million, so that the a priori chance
that an individual taken at random will be so affected is
only one in a million. Let the population consist of sixty
millions, composed, we will assume, of ten million fami-
lies, each containing six members. On these data, Pro-
fessor Stokes has calculated for me that the odds will be
no less than 8333 millions to 1 that in the ten million
families there will not be even a single family in which
one parent and two children will be affected by the pecu-
liarity in question. But numerous cases could be given,
in which several children have been affected by the same
rare peculiarity with one of their parents ; and in this
case, more especially if the grandchildren be included in
the calculation, the odds against mere coincidence be-
come something prodigious, almost beyond enumeration.
In some respects the evidence of inheritance is more
striking when we consider, the reappearance of trifling
peculiarities. Dr. Hodgkin formerly told me of an Eng-
lish family in which, for many generations, some members
had a single lock differently coloured from the rest of the •
hair. I knew an Irish gentleman, who, on the right side
of his head, had a small white lock in the midst of his
dark hair: he assured me that his grandmother had a
similar lock on the same side, and his mother on the op-
posite side. But it is superfluous to give instances ; every
shade of expression, which may often be seen alike in
parents and children, tells the same story. On what a
curious combination of corporeal structui-e, mental charac-
ter, and training, must handwriting depend! yet every
one must have noted the occasional similarity of the
handwriting in father and son, although the father had
not taught the son. A great collector of franks assured
me that in his collection there were several franks of
father and son hardly distinguishable except by their
dates. Hofacker, in Germany, remarks on the inheritance

Ciup. XII. INHERITANCE. 15

of handwriting ; and it has even been asserted that Eng-
lish boys when taught to write in France naturally cling
to their English manner of writing.8 Gait, gestures, voice,
and general bearing arc all inherited, as the illustrious
Hunter and Sir A. Carlisle have insisted.9 My father
communicated to me two or three striking instances, in
one of which a man died during the early infancy of his
son, and my father, who did not see this son until grown
up and out of health, declared that it seemed to him as
if his old friend had risen from the grave, with all his
highly peculiar habits and manners. Peculiar manners
pass into tricks, and several instances could be given of
their inheritance ; as in the case, often quoted, of the fa-
ther who generally slept on his back, with his right leg
crossed over the left, and whose daughter, whilst an in-
fant in the cradle, followed exactly the same habit, though
an attempt was made to cure her.10 I will give one in-
stance which has fallen under my own observation, and
which is curious from being a trick associated with a pe-
culiar state of mind, namely, pleasurable emotion. A boy
had the singular habit, when pleased, of rapidly moving
his fingers parallel to each other, and, when much excit-
ed, of raising both hands, with the fingers still moving,
to the sides of his face on a level with the eyes; this boy,
when almost an old man, could still hardly resist this
trick when much pleased, but from its absurdity conceal-
ed it. He had eight children. Of these, a girl, when
pleased, at the age of four and a half years, moved her
fingers in exactly the same way, and what is still odder,
when much excited, she raised both her hands, with her
fingers still moving, to the sides of Jier face, in exactly
the same manner as her father had done, and sometimes
even still continued to do when alone. I. never heard of

8 nofacker, ' UeberdieEigenschaften,' Researches,' p. 530. Sir A. Carlisle,

Ac, 1828, >. 34. Report by Pariset in 'PhiL Transact.,' 1814, p. 94.

' Comptes Rendus,' 1S47, p. 592, I0 Girou de Buzareignues, ' De la

8 Hunter, as quoted in Harlan's ' Med. Generation,' p. 2S2.

16 INHERITANCE. Chap. XII.

any one excepting this one man and his little daughter
who had this strange habit ; and certainly imitation was
in this instance out, of the question.

Some writers have doubted whether those complex
mental attributes, on which genius and talent depend, are
inherited, even when both parents are thus endowed.
But he who will read Mr. Galton's able paper11 on heredi-
tary talent will have his doubts allayed.

Unfortunately it matters not, as far as inheritance is
concerned, how injurious a quality or structure may be if
compatible with life. No one can read the many trea-
tises12 on hereditary disease and doubt this. The ancients
were strongly of this opinion, or, as Ranchin expresses it,
Omnes Gneci, Arabes, et Latini in eo consentiunt. A
long catalogue could be given of all sorts of inherited
malformations and of predisposition to various diseases.
With gout, fifty per cent, of the cases observed in hospi-
tal practice are, according to Dr. Garrod, inherited, and
a greater percentage in private practice. Every one
knows how often insanity runs in families, and some of
the cases given by Mr. Sedgwick are awful, — as of a sur-
geon, whose brother, father, and four paternal uncles
were all insane, the latter dying by suicide ; of a Jew,
whose father, mother, and six brothers and sisters were
all mad ; and in some other cases several members of the
same family, during three or four successive generations,
have committed suicide. Striking instances have been

i1 ' Macmillau's Magazine,' July and dans les Maladies,' 1S40. Adams, ' A

August, 1865. Philosophical Treatise on Hereditary Pe-

12 The works which I have read and culiarities,' 2nd edit., 1815. Essay on

found most useful are Dr. Prosper Lucas's ' Hereditary Diseases,' by Dr. J. Steinan,

great work, 'Traite de l'Heredite Na- 1S43. See Paget, in 'Medical Times,'

turelle,' 1847. Mr. W. Sedgwick, in 1S57, p. 192, on the Inheritance of Cafc-

' British and Foreign Medico-Chirurg cer ; Dr. Gould, in ' Proc. of American

Review,' April and July, 1861, and April Acad, of Sciences,' Nov. 8, 1853, gives a

and July, 1863 : Dr. Garrod on Gout is curious case of hereditary bleeding in

quoted in these articles. Sir Henry Hoi- four generations. Harlan, ' Medical Re-

land, ' Medical Notes and Reflections,' searches,' p. 593.
3rd edit., 1S55. Piorry, 'De l'Heredite

Chap. XII. INHERITANCE. 17

recorded of epilepsy, consumption, asthma, stone in the
bladder, cancer, profuse bleeding from the slightest in-
juries, of the mother not giving milk, and of bad partu-
rition being inherited. In this latter respect I may men-
tion an odd case given by a good observer,13 in which the
fault lay in the offspring, and not in the mother: in a
part of Yorkshire the farmers continued to select cattle
with large hind-quarters, until they made a strain called
" Dutch-buttocked," and " the monstrous size of the but-
tocks of the calf was frequently fatal to the cow, and
numbers of cows were annually lost in calving."

Instead of g'mng numerous details on various inherited malfor-
mations and diseases, I will confine myself to one organ, that which
is the most complex, delicate, and probably best-known in the hu-
man frame, namely, the eye, with its accessory parts. To begin
with the latter : I have heard of a family in which parents and
children were affected by drooping eye-lids, in so peculiar a manner
that they could not see without throwing their heads backwards;
and Sir A. Carlisle14 specifies a pendulous fold to the eyelids as in-
herited. " In a family," says Sir H. Holland,15 "where the father
had a singular elongation of the upper eyelid, seven or eight chil-
dren were born with the same deformity ; two or three other chil-,
dren having it not." Many persons, as I hear from Mr. Paget, have
two or three of the hairs in their eyebrows (apparently correspond-
ing with the vibrissa? of the lower animals) much longer than the
others ; and even so trifling a peculiarity as this certainly runs in
families.

With respect to the eye itself, the highest authority in England,
Mr. Bowman, has been so kind as to give me the following remarks
on certain inherited imperfections. First, hypermetropia, or mor-
bidly long sight : in this affection, the organ, instead of being
spherical, is too flat from front to back, and is often altogether too
small, so that the retina is brought too forward for the focus of the
humours ; consequently a convex glass is required for clear vision
of near objects, and frequently even of distant ones. This state
occurs congenital!}', or at a very early age, often in several children

13 Marshall, quoted by Youatt in his 15 ' Medical Notes and Reflections,' 3rd

work on Cattle, p. 2S4. edit., p. 33.

" Thilosoph. Transact.,' 1S14, p. 94.

18 IXHERITANCE. Chap. XII.

of the Bame family, where one of the parents has presented it.16
Secondly, myopia, or short-sight, in which the eye is egg-shaped,
and too long from front to back ; the retina in this case lies behind
the focus, and is therefore fitted to see distinctly only very near ob-
jects. This condition is not commonly congenital, but comes on in
youth, the liability to it being well known to be transmissible from
parent- to child. The change from the spherical to the ovoidal
shape seems the immediate consequence of something like inflam-
mation of the coats, under which they yield, and there is grounti for
believing that it may often originate in causes acting directly on
the individual affected, and may thenceforward become transmis-
sible. When both parents are myopic Mr. Bowman has observed the
hereditary tendency in this direction to be heightened, and some of
the children to be myopic at an earlier age or in a higher degree
than their parents. Thirdly, squinting is a familiar example of
hereditary transmission : it is frequently a result of such optical de-
fects as have been above mentioned ; but the more primary and un-
complicated forms of it are also sometimes in a marked degree
transmitted in a family. Fourthly, Cataract, or opacity of the crys-
talline lens, is commonly observed in persons whose parents have
been similarly affected, and often at an earlier age in the children
than in the parents. Occasionally more than one child in a family
is thus afflicted, one of whose parents or other relation presents the
senile form of the complaint. When cataract affects several mem-
bers of a family in the same generation, it is often seen to commence
at about the same age in each ; e.g., in one family several infants or
young persons may suffer from it ; in another, several persons of
middle age. Mr. Bowman also informs me that he has occasionally
seen, in several members of the same family, various defects in
either the right or left eye ; and Mr. White Cooper has often seen
peculiarities of vision confined to one eye reappearing in the same
eye in the offspring.17

The following cases are taken from an able paper by Mr. W.
Sedgwick, and from Dr. Prosper Lucas.18 Amaurosis, either con-
genital or coming on* late in life, and causing total blindness, is
often inherited ; it has been observed in three successive genera-
tions. Congenital absence of the iris has likewise been transmitted
for three generations, a cleft-iris for four generations, being limited

18 This affection, as I hear from Mr. 17 Quoted by Mr. Herbert Spencer,

Bowman, has been ably described and ' Principles of Biology,' vol. i. p. 244.

spoken of as hereditary by Dr. Donders 18 ' British and Foreign Medico-Chi-

of Utrecht, whose work was published in rurg. Review,' April, 1861, p. 4S2-6;

English by the Sydenham Society in 1864. ' l'Hered. Nat.,' torn. i. pp. 391-408.

Chap. XII. ' INHERITANCE. 19

in this latter case to the males of the family. Opacity of the cornea
and congenital smallness of the eyes have been inherited. Portal
records a curious case, in which a father and two sons were rendered
blind, whenever the head was bent downwards, apparently o win g
to the crystalline lens, with its capsule, slipping through an unusu-
ally large pupil into the anterior chamber of the eye. Day-blindness,
or imperfect vision under a bright light, is inherited, as is night-
blindness, or an incapacity to see except under a strong light : a
case has been recorded, by M. Cunier, of this latter defect having
affected eighty-five members of the same family during six genera-
tions. The singular incapacity of distinguishing colours, which
has been called Daltonism, is notoriously hereditary, and has been
traced through five generations, in which it was confined to the fe-
male sex.

With respect to the colour of*the iris: deficiency of colouring
matter is well known to be hereditary in albinoes. The iris of one
rye being of a different colour from that of the other, and the iris
being spotted, are cases which have been inherited. Mr. Sedgwick
gives, in addition, on the authority of Dr. Osborne,19 the following
curious instance of strong inheritance : a family of sixteen sons and
five daughters all had eyes " resembling in miniature the markings
on the back of a tortoiseshell cat." The mother of this large family
had three sisters and a brother all similarly marked, and they de-
rived this peculiarity from their mother, who belonged to a family
notorious for transmitting it to their posterity.

Finally, Dr. Lucas emphatically remarks that there is not one
single faculty of the eye which is not subject to anomalies ; and not
one which is not subjected to the principle of inheritance. Mr.
Bowman agrees with the general truth of this proposition ; which
of course does not imply that all malformations are necessarily in-
herited ; this would not even follow if both parents were affected by
an anomaly which in most cases was transmissible.

• Even if no single fact had been known with respect to
the inheritance of disease and malformations by man, the
evidence would have been ample in the case of the horse.
And this might have been expected, as horses breed much
quicker than man, are matched with eare, and are highly-
valued. I have consulted many works, and the unani-

19 Dr. Osborne, Prest. of Royal Col- case in the ' Dublin Medical Journal ' for
lege of Puys. in Ireland, published this 1833.

20 INHERITANCE. Chap. XI r.

mity of the belief by veterinaries of all nations in the
transmission of various morbid tendencies is surprising.
Authors, who have had wide experience, give in detail
many singular cases, and assert that contracted feet, with
the numerous contingent evils, of ring-bones, curbs,
splints, spavin, founder and weakness of the front legs,
roaring -or broken and thick wind, melanosis," specific
ophthalmia, and blindness (the great French veterinary
Hazard going so far as to say that a blind race could
soon be formed), crib-biting, jibbing, and ill-temper, are
all plainly hereditary. Youatt sums up by saying " there
is scarcely a malady to which the horse is subject which
is not hereditary ;" and M. Bernard adds that the doc-
trine " that there is scarcely a disease which does not run
in the stock, is gaining new advocates every day."20 So
it is in regard to cattle, with consumption, good and bad
teeth, fine skin, &c. &c. But enough, and more than
enough, has been said on disease. Andrew Knight, from
his own experience, asserts that disease is hereditary with
plants ; and this assertion is endorsed by Lindley.21

Seeing how hereditary evil qualities are, it is fortunate
that good health, vigour, and longevity are equally inher-
ited. It was formerly a well-known practice, when an-
nuities were purchased to be received during the lifetime
of a nominee, to search.out a person belonging to a family
of which many members had lived to extreme old age.

2° These various statements are taken in vol. vi. pp. 66, 346, 412 ; M. Bernard,
from the following works and papers : — vol. xi. r. 539 ; Dr. Samesreuther, on
Youatt on 'The Horse,' pp. 35, 220. Cattle, in vol. xii. p. 1S1 ; Percivall, in
Lawrence, ' The Horse,' p. 30. Karkeek, vol. xiii. p. 47. With respect to blind-
in an excellent paper in ' Gard. Chro- ness in horses, see also a whole row of
nicle,' 1853, p. 92. Mr. Burke, in 'Jour- authorities in Dr. P. Lucas's great work,
nal of R. Agricul. Soc. of England,' vol. torn. i. p. 399. Mr. Baker, in ' The Yete-
v. p. 511. ' Encyclop. of Rural Sports,' rinary,' vol. xiii. p. 721, gives a strong
p. 279. Girou de Buzareignues, ' Phi- case of hereditary imperfect vision and
losoph. Phys.,' p. 215. See following of jibbing.

papers in ' The Veterinary :' Roberts in 21 Knight on ' The Culture of the

vol. ii. p. 144 ; M. Marrimpoey, vol. ii. p. Apple and Pear,' p. 34. Lindley 's ' Hor-

387 ; Mr. Karkeek, vol. iv. p. 5 ; Youatt ticulture,' p. 180.
on Goitre in Dogs, vol. v. p. 483 ; Youatt,

Chap. XII. INHERITANCE. 21

As to the inheritance of vigour and endurance, the Eng-
lish race-horse offers an excellent instance. Eclipse begot
334, ami King Herod 497 winners. A "cock-tail" is a
horse not purely bred, but with only one-eighth or one-
sixteenth impure blood in his veins, yet very few in-
stances have ever occurred of such horses having won a
great race. They are sometimes as fleet for short dis-
tances as thoroughbreds, but as Mr. Robson, the great
trainer, asserts, they are deficient in wind, and cannot
keep up the pace. Mr. Lawrence also remarks, " perhaps
no instance has ever occurred of a three-part-bred house
saving his ' distance'' in running two miles with thorough-
bred racers." It has been stated by Cecil, that when
unknown horses, whose parents were not celebrated, have
unexpectedly won great races, as in the case of Priam,
they can always be proved to be descended on both
sides, through many generations, from first-rate ances-
tors. On the Continent, Baron Cameronn challenges, in
a German veterinary periodical, the opponents of the
English race-horse, to name one good horse on the Con-
tinent which has not some English race-blood in his
veins.22

With respect to the transmission of the many slight,
but infinitely diversified characters, by which the do-
mestic races of animals and plants are distinguished,
nothing need be said ; for the very existence of persis-
tent races proclaims the power of inheritance.

A few special cases, however, deserve some considera-
tion. It might have been anticipated, that deviations
from the law of symmetry would not have been inher-
ited. But Anderson23 states that a rabbit produced in

9a These statements are taken from ""Horse,' 1S29, p. 9 ; ' The Stud Farm,' by

the following works in order : — Youatt Cecil, 1S51 ; Baron Cameronn, quoted in

on ' The Horse,' p. 4S ; Mr. Darvill, in ' The Veterinary,' vol. x. p. 500.

' The Veterinary,' vol. viii. p. 50. With 23 ' Recreations in Agriculture and

respect to Robson, see ' The Veterinary,' Nat. Hist.,' vol. i. p. 68.
vol. Hi. p. 580 ; Mr. Lawrence on ' The

22 INHERITANCE. Chap. XII.

a litter a young animal having only one ear; and from
this animal a breed was formed which steadily produced
one-eared rabbits. He also mentions a bitch, with a
single leg deficient, and she produced several puppies
with the same deficiency. From Hofacker's account24 it
appears that a one-horned stag was seen in 1781 in a
forest in Germany, in 1788 two, and afterwards, from
year to year, many were observed with only one horn
on the right side of the head. A cow lost a horn by
suppuration,25 and she j>i'oduced three calves which had
on the same side of the head, instead of a horn, a small
bony lump attached merely to the skin; but we here
approach tbe doubtful subject of inherited mutilations.
A man who is left-handed, and a shell in which the spire
turns in the wrong direction, are departures from the
normal though a symmetrical condition, and they are well
known to be inherited.

Polydactylism. — Supernumerary fingers and toes are eminently
liable, as various authors have- insisted, to transmission, but tliey
are noticed here chiefly on account of their occasional regrowth
after amputation. Polydactylism graduates26 by multifarious steps
from a mere cutaneous appendage, not including any bone, to a
double hand. But an additional digit, supported on a metacarpal
bone, and furnished with all the proper muscles, nerves, and ves-
sels, is sometimes so perfect, that it escapes detection, unless the
fingers are actually counted. Occasionally there are several super-
numerary digits ; but usually only one, making the total number
six. This one may represent either a thumb or finger, being at-
tached to the inner or outer margin of the hand. Generally,
through the law of correlation, both hands and feet are similarly
affected. I have tabulated the cases recorded in various works or
privately communicated to me, of forty-six persons with extra
digits on one or both hands and feet ; if in each case all four
extremities had been similarly affected, the table would have

2* ' Ueber die Eigcnschaften,' &c, full length in a work published in Dutch,

1S2S, s. 107. from which Mr. Paget has kindly trans-

2*5 Bronn's ' Geschichte der Natur,' lated for me passages. See, also, Isidore

band. ii. s. 132. Geoffroy St. Hilaire's ' Hist, des Ano-

ae vrolik has discussed this point at malies,' 1832, torn. i. p. 684.

Chap. XII. INHERITANCE. 23

shown a total of ninety-two hands and ninety-two feet each with
six dig-its. As it is, seventy-three hands and seventy-five feet were
thus affected. This proves, in contradiction to the result arrived at
by Dr. Struthers,27 that the hands are not more frequently affected
than the feet.

The presence of more than five digits is a great anomaly, for
this number is not normally exceeded by any mammal, bird, or
existing reptile.-8 Nevertheless, supernumerary digits are strongly
inherited ; they have been transmitted through five generations ;
•and in some cases, after disappearing for one, two, or even three
generations, have reappeared through reversion. These facts are
rendered, as Professor Huxley has observed, more remarkable from
its being known in most cases that the affected person had not mar-
ried one similarly affected. In such cases the child of the fifth gen-
eration would have only l-32nd .part of the blood of his first sedig-
itated ancestor. Other cases are rendered remarkable by the affec-
tion gathering force, as Dr. Struthers has shown, in each generation,
though in each the affected person had married one not affected ;
moreover such additional digits are often amputated soon after
birth, and can seldom have been strengthened by use. Dr. Struth-
ers gives the following instance : in the first generation an addi-
tional digit appeared on one hand ; in the second, on both hands ;
in the third, three brothers had both hands, and one of the broth-
ers a foot affected ; and in the fourth generation all four limbs
were affected. Yet we must not over-estimate the force of inher-
itance. Dr. Struthers asserts that cases of non-inheritance and of
the first appearance of additional digits in unaffected families are
much more frequent than cases of inheritance. Many other devia-
tions of structure, of a nature almost as anomalous as supernumer-
ary digits, such as deficient phalanges, thickened joints, crooked
fingers, &c, are in like manner strongly inherited, and are equally
subject to intermission with reversion, though, in such cases there
is- no reason to suppose that both parents had been similarly af-
fected.29

*7 'Edinburgh New Phil. Journal,' resembles under the microscope, in a

July, 1863. remarkable manner, a digit. But the

2» Some great anatomists, as Cuvier highest authority on such subjects, Ge-
and Meckel, believe that the tubercle genbaur (Untersuchung. zur vergleich.
on one side of the hinder foot of the anat. der Wirbelthiere : Carpus et Tar-
tailless Batrachians represents a sixth sus, 1S64, s. 63), concludes that this re-
digit. Certainly, when the hinder foot semblance is not real, only superficial,
of a toad, as soon as it first sprouts aa For these several statements, see
from the tadpole, is dissected, the par- Dr. Struthers, in work cited, especially
tlalfy ossified cartilage of this tubercle on intermissions in the line of descent.

24 INHERITANCE. Chap. XII.

Additional digits have been observed in negroes as well as in
ether races of man, and in several of the lower animals. Six toes
have been described on the hind feet of the newt (Salamandra cris-
taia), and, as it is said, of the frog. It deserves notice from what
follows, that the six-toed newt, though adult, had preserved some
of its larval characters ; for part of the hyoidal apparatus, which is
properly absorbed during the act of metamorphosis, was retained.
In the dog, six toes on the hinder feet have been transmitted
through three generations ; and I have heard of a race of six-toed
cats. In several breeds of the fowl the hinder toe is double, and is
generally transmitted truly, as is well shown when Dorkings are
crossed with common four-toed breeds.30 With animals which
have properly less than five digits, the number is sometimes in-
creased to five, especially in the front legs, though rarely carried
beyond that number ; but this is due to the development of a digit
already existing in a more or less rudimentary state. Thus the
dog has properly four toes behind, but in the larger breeds a fifth
toe is commonly, though not perfectly, developed. Horses, which
properly have one toe alone fully developed with rudiments of the
others, have been described with each foot bearing two or three
small separate hoofs : analogous facts have been noticed with
sheep, goats, and pigs.31

The most interesting point with respect to supernumerary digits
is their occasional regrowth after amputation. Mr. White32 de-
scribes a child, three years old, with a thumb double from the
first joint. He removed the lesser thumb, which was furnished
with a nail ; but to his astonishment it grew again, and reproduced
a nail. The child was then taken to an eminent London surgeon,
and the newly-grown thumb was wholly removed by its socket-
joint, but again it grew and reproduced a nail. Dr. Struthers

Prof. Huxley, 'Lectures on our Know- cit., April 1S63, p. 490. With respect
ledge of Organic Nature,' 1S63, p. 97. to additional digits in the negro, nee
With respect to inheritance, see Dr. Pricliard, ' Physical History of Man-
Prosper Lucas, 'L'Heredite Nat.,' torn, kind.' Dr. Dieffenbach (' Journ. Royal
i. p. 325. Isid. GeofTroy, ' Anom.,' torn. Geograph. Soc.,' 1841, p. 20S) says this
i. p. 701. Sir A. Carlisle, in 'Phil. anomaly is not uncommon with the
Transact.,' 1S14, p. 94. A.Walker, on Polynesians of the Chatham Islands.
'Intermarriage,' 1S38, p. 140, gives a so ' The Poultry Chronicle,' 1854, p.
case of five generations ; as does Mr. 559.

Sedgwick, in ' Brit, and Foreign Medico- 31 The statements in this paragraph

Chirurg. Review,' April, 1863, p. 462. are taken from Isidore GeofTroy St. Hi-

On the inheritance of other anomalies laire, 'Hist, des Anomalies,' torn. i. pp.

in the extremities, see Dr. H. Dobell, in 6S8-693.

vol. xlvi. of 'Medico-Chirurg. Tiansac- 32 As quoted by Carpenter, 'Princ

tions,' 1SC3 ; also Mr. Sedgwick, in op. of Comp. Physiology,' 1854, p. 480.

Chap. XII. INHERITANCE. 25

mentions a case of partial regipwth of an additional thumb, ampu
tated when the child was three months old ; and the late Dr. Fal-
coner communicated to me an analogous case which had fallen
under his own observation. A gentleman, who first called my
attention to this subject, has given me the following facts which
occurred in his own family. He himself, two brothers, and a sis-
ter were born with an extra digit to each extremity. His parents
were not affected, and there was no tradition in the family, or in
the village in which the family had long residgd, of any member
having been thus affected. Whilst a child, both additional toes,
which were attached by bones, were rudely cut off; but the stump
of one grew again, and a second operation was performed in his
thirty-third year. He has had fourteen children, of whom three have
inherited additional digits ; and one of them, when about six weeks
old, was operated on by an eminent surgeon. The additional fin-
ger, which was attached by bone to the outer side of the hand, was
removed at the joint ; the wound healed, but immediately the
digit began growing ; and in about three months' time the stump
was removed for the second time by the root. But it has since
grown again, and is now fully a third of an inch in length, in-
cluding a bone ; so that it will for the third time have to be ope-
rated on.

Xow the normal digits in adult man and other mammals, in
birds, and, as I believe, in true reptiles, have no power of regrowth.
The nearest approach to this power is exhibited by the occasional
reappearance in man of imperfect nails on the stumps of his fingers
after amputation/3 But man in his embryonic condition has a con-
siderable power of reproduction, for Sir J. Simpson 3i has several
times observed arms which had been cut off in the womb by bands
of false membrane, and which had grown again to a certain extent.
In one instance, the extremity was " divided into three minute nod-
ules, on two of which small points of nails could be detected ;" so
that these nodules clearly represented fingers in process of re-
growth. When, however, we descend to the lower vertebrate
classes, which are generally looked at as representing the higher
classes in their embryonic condition, we find ample powers of re-
growth. Spallanzani 35 cut off the legs and tail of a salamander six

83 Muller's * Phys.,' Eng. translat., 34 'Monthly Journal of Medical Sci-

vol. i. 1S3S, p. 407. A thrush, however, ence,' Edinburgh, 1S4S, new series, vol.

was exhibited before the British Associa- ii. p. S90.

tion at Hull, in 1868, which had lost its 35 ' An Essay on Animal Reproduc-

btnoa, and this member, it was asserted, tion,' trans, by Dr. Maty, 1769, p. 79.
had been thrice reproduced : I presume
It was lost each lime by disease.

26 INHERITAISTCE. Chap. XIL

times, and Bonnet eight times, successively, and they were repro-
duced. An additional digit beyond tlie proper number was occa-
sionally formed after Bonnet had cut off or had divided longitudi-
nally the hand or foot, and in one instance three additional digits
were thus formed.30 These latter cases appear at first sight quite
distinct from the congenital production of additional digits in the
higher animals ; but theoretically, as we shall see in a future chap-
ter, they probably present no real difference. The larvae or tad-
poles of the taille« Batrachians, but not the adults,37 are capable
of reproducing lost members.38 Lastly, as I have been informed by
Mr. J. J. Briggs and Mr. F. Buckland, when portions of the pectoral
and tail fins of various fresh-water fish are cut off, they are perfect-
ly reproduced in about six weeks' time.

From these several facts we may infer that supernu-
merary digits in man retain to a certain extent an em-
bryonic condition, and that they resemble in this respect
the normal digits and limbs in the lower vertebrate
classes. They also resemble the digits of some of the
lower animals in the number exceeding five ; for no mam-
mal, bird, existing reptile, or amphibian (unless the tu-
bercle on the hind feet of the toad and other tailless
Batrachians be viewed as a digit) has more than five ;
Avhilst fishes sometimes have in their pectoral tins as
many as twenty metacarpal and phalangeal bones, which,
together with the bony filaments, apparently represent
our digits with their nails. So, again, in certain extinct
reptiles, namely, the Ichthyopterygia, " the digits may
be seven, eight, or nine in number, a significant mark,"
says Professor Owen, " of piscine affinity." 39

We encounter much difficulty in attenuating to reduce

38 Bonnet, ' 02uvresd'Hist. Nat.,' torn, on this whole subject by Dr. Carpentet

v., part i., 4to. edit., 1TS1, pp. 343, £50, in his ' Princ. Comp. Phys.,' 1S54, p. 479.

353. 38 Dr. Gunther, in Owen's ' Anatomy

37 So with insects, the larvse reproduce of Vertebrates,' vol. i.,' 1866, p. 567.

lost limbs, but, except in one order, the Spallanzani has made similar observa

mature insect has no such power. But tions.

the Myriapoda, which apparently repre- 39 ' On the Anatomy of Vertebrates,'

sent the larvse of true insects, have, as 1S66, p. 170 : with respect to the pectoral

Newport has shown, this power until their fins of fishes, pp. 106-168. •
last moult. See an excellent discussion

Chap. XII. INHERITANCE. 27

these various facts to any rule or law. The inconstant
number of the additional digits — their irregular attach-
ment to either the inner or outer margin of the hand —
the gradation which can be traced from a mere loose ru-
diment of a single digit to a completely double hand —
the occasional appearance of additional digits in the sala-
mander after a limb has been amputated — these various
facts appear to indicate mere fluctuating monstrosity ;
and this perhaps is all that can be safely said. Neverthe-
less, as supernumerary digits in the higher animals, from
their power of regrowth and from the number thus ac-
quired exceeding five, partake of the nature of the digits
in the lower vertebrate animals ; — as they occur by no
means rarely, and are transmitted with remarkable
strength, though perhaps not more strongly than some
other anomalies ; — and as with animals which have fewer
than five digits, when an additional one appears it is
generally due to the development of a visible rudiment ; —
we are led in all cases to suspect, that, although no actu-
al rudiment can be detected, yet that a latent tendency
to the formation of an additional digit exists in all mam-
mals, including man. On this view, as we shall more
plainly see in the next chapter when discussing latent
tendencies, we should hare to look at the whole case as
one of reversion to an enormously remote, lowly-organi-
sed, and multidigitate progenitor.

I may here allude to a class of facts closely allied to,
but somewhat different from, ordinary cases of inheri-
tance. Sir H. Holland40 states that brothers and sisters
of the Same family are frequently affected, often at about
the same age, by the same peculiar disease, not known to
have previously occurred in the family. He specifies the
occurrence of diabetes in three brothers under ten yeara

40 ' Medical Notes and Reflections,' 1S39, pp. 24, 31. See, also, Dr. P. Lucas,
l'H6red. Nat.,' torn. ii. p. 83.

28 ' INHERITANCE. Chap, XII.

old; he also remarks that children of the same family of-
ten exhibit in common infantile diseases the same pecu-
liar symptoms. My father mentioned to me the case of
four brothers who died between the ages of sixty and se-
venty, in the same highly peculiar comatose state. An
instance has been already given of supernumerary digits
appearing in four children out of six in a previously unaf-
fected family. Dr. Devay41 states that two brothers
married two sisters, their first-cousins, none of the four
nor any relation being an albino ; but the seven children
produced from this double marriage were all perfect
albinoes. Some of these cases, as Mr. SedgAvi.ck 42 has
shown, are probably the result of reversion to a remote
ancestor, of whom no record had been preserved ; and all
these cases are so far directly connected with inheritance
that no doubt the children inherited a similar constitution
from their parents, and, from being exposed to nearly
similar conditions of life, it is not surprising that they
should be affected in the same manner and at the same
period of life.

Most of the facts hitherto given have served to illus-
trate the force of inheritance, but we must now consider
cases, grouped as well as the subject allows into classes,
showing how feeble, capricious, or deficient the power of
inheritance sometimes is. When a new peculiarity first
appears, we can never predict whether it will be inherited.
If both parents from their birth present the same peculi-
arity, the probability is strong that it will be transmitted
to at least some of their offspring. We have seen that
variegation is transmitted much more feebly by seed
from a branch which had become variegated through
bud-variation, than from plants which were variegated
as seedlings. With most plants the power of transmis-

41 'Du Danger des Manages Consan- 42 ' British and Foreign Medico-Chi-

guins,' 2nd edit., 1S62, p. 103. rurg. Review,' July, 1363, pp. 1S3, 1S9.

Chap. xii. INHERITANCE. 29

sion notoriously depends on some innate capacity in the
individual: thus Vilmorin43 raised from a peculiarly co-
loured balsam some seedlings, which all resembled their
parent ; but of these seedlings some failed to transmit the
new character, whilst others transmitted it to all their
descendants during several successive generations. So
again with a variety of the rose, two plants alone out of
six were found by Vilmorin to be capable of transmitting
the desired character.

The weeping or pendulous growth of tre^s is strongly inherited
in some cases, and, without any assignable reason, feebly in other
cases. I have selected this character as an instance of capricious
inheritance, because it is certainly not proper to the parent-species,
and because, both sexes being toorne on the same tree, both tend to
transmit the same character. Even supposing that there may have
been in some instances crossing with adjoining trees of the same
species, it is not probable that all the seedlings would have been
thus affected. At Moccas Court there is a famous weeping oak ;
many of its branches " are 30 feet long, and no thicker in any
part of this length than a common rope :" this tree transmits its
weeping character, in a greater or less degree, to all its seedlings :
some of the young oaks being so flexible that they have to be sup-
ported by props ; others not showing the weeping tendency till
about twenty years old.44 Mr. Rivers fertilized, as he informs me,
the flowers of a new Belgian weeping thorn {Crataegus oxyacantha)
with pollen from a crimson not-weeping variety, and three young
trees, " now six or seven years old, show a decided tendency to be
pendulous, but as yet are not so much so as the mother-plant."
According to Mr. McXab,45 seedlings from a magnificent weeping
birch (Betula alba), in the Botanic Garden at Edinburgh, grew for
the first ten or fifteen years upright, but then all became weepers
like their parent. A peach with pendulous branches, like those of
the weeping willow, has been found capable of propagation by
seed.46 Lastly, a weeping and almost prostrate yew ( Taxusbaccata)
was found in a hedge in Shropshire ; it was a male, but one branch
bore female flowers, and produced berries ; these, being sown, pro-

43 Verlot, ' La Production des Varie- 45 Verlot, ' La Product, des Varietes,'

t6s,' 1865, p. 32. 1865, p. 94.

' 44 Loudon's ' Gard. Mag.,' vol. xii., 46 Bronn's ' Geschichte der Natur,' b.

1886, p. 36-8. ii. s. 121.

30 INHERITANCE. Chap. XIL

duced seventeen trees, all of which had exactly the same peculiar
habit with the parent-tree.47

These facts, it might have been thought, would have been suffi-
cient to render it probable that a pendulous habit would in all cases
be strictly inherited. But let us look to the other side. Mr. Mac-
Nab48 sowed seeds of the weeping beech (Fagus sylmtica), but suc-
ceeded in raising only common beeches. Mr. Rivers, at my request,
raised a number of seedlings from three distinct varieties of weeping
elm ; and at least one of the parent-trees was so situated that it
could not have been crossed by any other elm ; but none of the
young trees, now about a foot or two in height, show the least
signs of weeping. Mr. Rivers formerly sowed about twenty thou-
sand seeds of the weeping ash (Fraxinus excelsior), and not a single
seedling was in the least degree pendulous : in Germany, M.
Borchmeyer raised % thousand seedlings, with the same result.
Nevertheless, Mr. Anderson, of the Chelsea Botanic Garden, by
sowing seed from a weeping ash, winch ^as found before the year
1780, in Cambridgeshire, raised several pendulous trees.49 Professor
Henslow also informs me that some seedlings from a female weep-
ing ash in the Botanic Garden at Cambridge were at first a little
pendulous, but afterwards became quite upright : it is probable that
this latter tree, which transmits to a certain extent its pendulous
habit, was derived by a bud from the same original Cambridgeshire
stock ; whilst other weeping ashes may have had a distinct origin.
But the crowning case, communicated to me by Mr. Rivers, which
shows how capricious is the inheritance of a pendulous habit, is
that a variety of another species of ash {F. lentiscifolia) which was
formerly pendulous, " now about twenty years old, has long lost
" this habit, every shoot being remarkably erect ; but seedlings
" formerly raised from it were perfectly prostrate, the stems not
" rising more than two inches above the ground." Thus the weep-
ing variety of the common ash, which has been extensively prop-
agated by buds during a long period, did not, with Mr. Rivers,
transmit its cbaracter to one seedling out of above twenty thousand ;
whereas the weeping variety of a second species of ash, which
could not, whilst grown in the same garden, retain its own weeping
character, transmitted to its seedlings the pendulous habit in
excess !

Many analogous facts could be given, showing how apparently

4T Rev. W. A. Leighton, ' Flora of «8 Verlot, op. cit., p. 93.

Shropshire, ' p. 497 ; and Charlesworth's 49 For these several statements, see

'Mag. of Nat. Hist.,' vol. i., 1837, p. Loudon's 'Gard. Magazine,' vol. x., 1534,

80. pp. 40S, ISO ; and vol. ix., 1S33, p. 597.

Chap. XII INHERITANCE. 31

capricious is the principle of inheritance. All the seedlings from a
variety of the Barberry (B. vulgaris) with red leaves inherited the
same character ; only about one-third of the seedlings of the copper
Beech (Fagus sylvatiea) had purple leaves. Not one out of a hundred
BeedlingS of a variety of the Cerasus pad us, with yellow fruit, bore
yellow fruit : one-twelfth of the seedlings of the variety of Comus
mascula, with yellow fruit, came true :50 and lastly, all the trees
raised by my father from a yellow-berried holly {Ilex aquifolium),
found wild, produced yellow berries, Vilmorin51 observed in a
bed of Saponaria calabriea an extremely dwarf variety, and raised
from it a large number of seedlings ; some of these partially re-
sembled their parent, and he selected their seed ; but the grand-
children were not in the least dwarfed : on the other hand, he ob-
served a stunted and bushy variety of Tagetes signata growing in
the midst of the common varieties by which it was probably
crossed ; for most of the seedlings raised from this plant were in-
termediate in character, only two perfectly resembling their parent ;
but seed saved from these two plants reproduced the new variety
so truly, that hardly any selection has since been necessary.

Flowers transmit their colour truly, or most capriciously. Many
annuals come true : thus I purchased German seeds of thirty-four
named sub-varieties of one race of ten-week stocks {MattJtiola annua),
and raised a hundred and forty plants, all of which, with the ex-
ception of a single plant, came true. In saying this, however, it
must be understood that I could distinguish only twenty kinds out
of the thirty-four named sub-varieties ; nor did the colour of the
flower always correspond with the name affixed to the packet ; but
I say that they came true, because in each of the thirty-six short
rows every plant was absolutely alike, with the one single excep-
tion. Again, I procured packets of German seed of twenty-five
named varieties of common and quilled asters, and raised a hun-
dred and twenty-four plants ; of these, all except ten were true in
the above limited sense ; and I considered even a wrong shade of
colour as false.

It is a singular circumstance that white varieties generally trans-
mit their colour much more truly than any other variety. This fact
probably stands in close relation with one observed by Verlot,62
namely, that flowers which are normally white rarely vary into any
other colour. I have found that the white varieties of Delphinium
consolida and of the Stock are the truest. It is, indeed, sufficient

60 These statements are taken from 61 Verlot, op. cit., p. 38.

Atph. De Candolle, ' Bot. Geograpu.,' p. »« Op. cit., p. 59.

1033.

32 INHERITANCE. Chap. XII.

to look through a nurseryman's seed-list, to see the large number of
white varieties which can he propagated by seed. The several
coloured varieties of the sweet-pea (Lathyrus odontitis) are very
true ;' but I hear from Mr. Masters, of Canterbury, who has par-
ticularly attended to this plant, that the white variety is the truest.
The hyacinth, when propagated by seed, is extremely inconstant
in colour, but " white hyacinths almost always give by seed white-
flowered plants ;"63 and Mr. Masters informs me that the yellow
varieties also reproduce their colour, but of different shades. On
the other hand, pink and blue varieties, the latter being the natural
colour, are not nearly so true : hence, as Mr. Masters has remarked
to me, " we see that a garden variety may acquire a more permanent
habit than a natural species ;" but it should have been added, that
this occurs under cultivation, and therefore under changed con-
ditions.

With many flowers, especially perennials, nothing can be more
fluctuating than the colour of the seedlings, as is notoriously the
case with verbenaB, carnations, dahlias, cinerarias, and others.64 I
sowed seed of twelve named varieties of Snapdragon (Antirrlrinum,
majus), and utter confusion was the result. In most cases the ex-'
tremely fluctuating colour of seedling plants is probably in chief
part due to crosses between differently-coloured varieties during
previous generations. It is almost certain that this is the case with
the polyanthus and coloured primrose (Primula xeris and vulgaris),
from their reciprocally dimorphic structure 5s6 and these are plants
which florists speak of as never coming true by seed ; but if care be
taken to prevent crossing, neither species is by any means very
inconstant in colour ; thus I raised twenty-three plants from a
purple primrose, fertilized by Mr. J. Scott with its own pollen, and
eighteen came up purple of different shades, and only five reverted
to the ordinary yellow colour : again, I raised twenty plants from
a bright-red cowslip, similarly treated by Mr. Scott, and every
one perfectly resembled its parent in colour, as likewise did, with
the exception of a single plant, 73 grandchildren. Even with the
most variable flowers, it is probable that each delicate shade of
colour might be permanently fixed so as to be transmitted by seed,
by cultivation in the same soil, by long-continued selection, and
especially by the prevention of crosses. I infer this from certain

*» Alph. De Candolle, ' Geograph. ' Card. Chron.,' 1S45, p. 102.

Bot.,' p. 10S2. 65 Darwin in 'Journal of Proc. Linn.

« See ' Cottage Gardener,' April 10, SoC. Bot.,' 1S62, p. 94.
1860, p. 18, and Sept. 10, 1861, p. 456;

Chap. XII. INHERITANCE* 33

annual larkspurs {Delphinium consolida and ajacis), of which com-
mon seedling's present a greater diversity of colour than any other
plant known to me ; yet on procuring seed of five named German
varieties of D. consolida, only nine plants out of ninety-four were
false ; and the seedlings of six varieties of D. ajacis "tfere true in the
same manner and degree as with the stocks above described. A
distinguished botanist maintains that the annual species of Del-
phinium are always self-fertilised ; therefore I may mention t,hat
thirty-two flowers on a branch of D. consolida, enclosed in a net,
yielded twenty-seven capsules, with an average of 172 in each ;
whilst five flowers, under the same net, which were artificially fer-
tilised, in the same manner as must be effected by bees during their
incessant visits, yielded five capsules with an average of 352 fine
seed ; and this shows that the agency of insects is necessary for the
full fertility of this plant. Analogous facts could be given with
respect to the crossing of many other flowers, such as carnations,
&c, of which the varieties fluctuate much in colour.

As with flowers, so with our domesticated animals, no character
is more variable than colour, and probably in no animal more so
than with the horse. Yet with a little care in breeding, it appears
that races of any colour might soon be formed. Hofacker gives the
result of matching two hundred and sixteen mares of four different
colours with like-coloured stallions, without regard to the colour of
their ancestors ; and of the two hundred and sixteen colts born,
eleven alone failed to inherit the colour of their parents : Auten-
rieth and Ammon assert that, after two generations, colts of a uni-
form colour are produced with certainty.56

In a few rare cases peculiarities fail to be inherited,
apparently from the force of inheritance being too strong*
I have been assured by breeders of the canary-bird that
to get a good jonquil-coloured bird it does not answer to
pair two jonquils, as the colour then comes out too strong,
or is even brown. So again, if two crested canaries are
paired, the young birds rarely inherit this character :" for
in crested birds a narrow space of bare skin is left on the
back of the head, where the feathers are up-turned to form

"• Hofacker, 'Ueber die Eigenschaf- breeder of canaries, informs me that

ten,' Ac, s. 10. he believes that these statements are

67 Bechstein, 'Naturgesch. Deutsch- correct,
lands,' b. iv. s. 462. Mr. Brent, a great

34 INHERITANCE. Chap. XIL

the crest, and, when both parents are thus characterised,
the bareness becomes excessive, and the crest itself fails
to be developed. Mr. Hewitt, speaking of Laced Se-
bright Bantams, says68 that, " why this should be so, I
know not, but I am confident that those that are best
laced frequently produce offspring very far from perfect
in their markings, whilst those exhibited by myself, which
have so often proved successful, were bred from the union
of heavily-laced birds with those that were scarcely suf-
ficiently laced."

It is a singular fact that, although several deaf-mutes
often occur in the same family, and though their cousins
and other relations are often in the same condition, yet
their parents are very rarely deaf-mutes. To give a single
instance: not one scholar out of 148, who were at the
same time in the -London Institution, was the child of
parents similarly afflicted. So again, Avhen a male or a
female deaf-mute marries a sound person, their children
are most rarely affected : in Ireland out of 203 children
thus produced one alone was mute. Even when both par-
ents have been deaf-mutes, as in the case of forty-one
marriages in the United States and of six in Ireland, only
two deaf and dumb children were produced. Mr. Sedg-
wick,69 in commenting on this remarkable and fortunate
failui'e in the power of transmission in the direct, line, re-
marks that it may possibly be owing to "excess having'
reversed the action of some natural law in development."
But it is safer in the present state of our knowledge to
look at the whole case as simply unintelligible.

With respect to the inheritance of structures mutilated
by injuries or altered by disease it is difficult to come to
any definite conclusion. In some cases mutilations have

•58 ' The Poultry Book,' by W. B. Te- Sedgwick has given such full details on

getmeier, 1866, p. 2-15. this subject, with ample references, that

69 ' British and Foreign Med.-Chirurg. I need refer to no other authorities.
Review,' July, 1861, pp. 2X-204. Mr.

CnAr. XII. INHERITANCE. 35

been practised for a vast number of generations without
any inherited result. Godron has remarked60 that differ-
ent races of man have from time immemorial knocked
out their upper incisors, cut off joints of their fingers,
made holes of immense size through the lobes of their
ears or through their nostrils, made deep gashes in vari-
ous parts of their bodies, and there is no reason what-
ever to suppose that these mutilations have ever been
inherited. Adhesions due to inflammation and pits from
the small-pox (and formerly many consecutive generations
must have been thus pitted) are not inherited. "With
respect to Jews, I have been assured by three medical
men of the Jewish faith that circumcision, which has
been practised for so many ages, has produced no inher-
ited effect ; Blumenbach, on the other hand, asserts61 that
in Germany Jews are often born in a condition rendering
circumcision difficult, so that a name is there applied to
them signifying " born circumcised." The oak and other
trees must have borne galls from primeval times, yet they
do not produce inherited excrescences ; many other such
facts could be adduced.

On the other hand, various cases have been recorded
of cats, dogs, and horses, which have had their tails, legs,
<fcc, amputated or injured, producing offspring with the
same parts ill-formed; but as it is not at all rare for
similar malformations to appear spontaneously, all such
cases may be due to mere coincidence. Nevertheless,
Dr. Prosper Lucas has given, on good authorities, such
a long list of inherited injuries, that it is difficult not to
believe in them. Thus, a cow that had lost a horn from
an accident with consequent suppuration, produced three
calves which were hornless on the same side of the head.
With the horse, there seems hardly a doubt that bony
exostoses on the legs, caused by too much travelling on

*° ' I)e 1'Espcr.e,' torn, ii., lS."i9, p. 200.

*l ' Pkilosop'u. Magazine,' voL iv., 1709, p. 5.

36 INHERITANCE. ChaK XII.

hard roads, are inherited. Blumenbach records the case
of a man who had his little finger on the right hand
almost cut off, and which in consequence grew crooked,
and his sons had the same finger on the same hand simi-
larly crooked. A soldier, fifteen years before his mar-
riage, lost his left eye from purulent ophthalmia, and his
two sons were microphthalmia *on the same side.63 In
all such cases, if truthfully reported, in which the parent
has had an organ injured on one side, and more than one
child has been born with the same organ affected on the
same side, the chances against mere coincidence are enor-
mous. But perhaps the most remarkable arid trust-
worthy fact is that given by Dr. Brown-Sequard,63 name-
ly, that many young guinea-pigs inherited an epileptic
tendency from parents which had been subjected to
a particular operation, inducing in the course of a few
weeks a convulshre disease like epilepsy : and it should
be" especially noted that this eminent physiologist bred a
large number of guinea-pigs from animals which had not
been operated on, and not one of these manifested the
epileptic tendency. On the whole, we can hardly avoid
admitting, that injuries and mutilations, especially when
followed by disease, or perhaps exclusively when thus
followed, are occasionally inherited.

Although many congenital monstrosities are inhei-ited,
of which examples have already been given, and to which
may be added the lately recorded case of the transmission
during a century of hare-lip with a cleft palate in the
writer's own family,64 yet other malformations are rarely
or never inherited. Of these latter cases, many are pro-

«2 This last case is quoted by Mr. Sedg- Baker in ' The Veterinary,1 vol. xiii. p.

wick in 'British and Foreign Medico- 723. Another curious case is given in

Chirurg. Review,' April, 1861, p. 4S4. the ' Annales des Scier.c. Nat.,' 1st series,

For Blumenbach, see above-cited paper. torn. xi. p. 324.

See, also, Dr. P. Lucas, ' Traite de 63 ' Proc. Royal Soc.,' vol. x. p. 297.

l'Hered. Nat.,' torn. ii. p. 492. Also e4 Mr. Sproule, in 'British Medical

• Transact. Linn. Soc.,' vol. ix. p. 323. Journal,' April 13, 1863.
Some curious cases are given by Mr.

Chap. XII. INHERITANCE. 3t

bably due to injuries in the womb or ego:, and would
come under the head of non-inherited injuries or mutila-
tions. With plants, a long catalogue of inherited mon-
strosities of the most serious and diversified nature could
easily be given ; and with plants, there is no reason to
suppose that monstrosities are caused by direct injuries
to the' seed or embryo.

Causes of Non-inheritance.

A large number of cases of non-inheritance are intelli
gible on the principle, that a strong tendency to inheri-
tance does exist, but that it is overborne by hostile or
unfavorable conditions of life. No one would expect
that our improved pigs, if forced during several genera-
tions to travel about and root in the ground for their
own subsistence, would transmit, as truly as they now
do, their tendency to fatten, and their short muzzles and
legs. Dray-horses assuredly would not long transmit
their great size and massive limbs, if compelled to live
on a cold, damp mountainous region ; we have indeed
evidence of such deterioration in the horses which have
run wild on the Falkland Islands. European dogs in
India often fail to transmit their true character. Our
sheep in tropical countries lose their wool in a few gene-
rations. There seems also to be a close relation between
certain peculiar pastures and the inheritance of an en-
larged tail in fat-tailed sheep, which form one of the most
ancient breeds in the world. With plants, we have seen
that the American varieties of maize lose their proper
character in the course of two or three generations, when
cultivated in Europe. Our cabbages, which here come
so true by seed, cannot form heads in hot countries.
Under changed circumstances, periodical habits of life
soon fail to be transmitted, as the period of maturity in
summer and winter wheat, barley, and vetches. So it is
with animals ; for instance, a person whose statement I

38 INHERITANCE. Chap. XII.

can trust, procured eggs of Aylesbury ducks from that
town, where they are kept in houses and are reared as early
as possible for the London market ; the ducks bred from
these eggs in a distant part of England, hatched their
first brood on January 24th, Avhilst common ducks, kept
in the same yard and treated in the same manner, did
not hatch till the end of March ; and this shows that the
period of hatching was inherited. But the grandchildren
of these Aylesbury ducks completely lost their early
habit of incubation, and hatched their eggs at the same
time with the common ducks of the same place.

Many cases of non-inheritance apparently result from
the conditions of life continually inducing fresh variabili-
ty. We have seen that when the seeds of pears, plums,
apples, &c, are sown, the seedlings generally inherit some
degree of family likeness from the parent-variety. Min-
gled with these seedlings, a few, and sometimes many,
worthless, wild-looking plants commonly appear ; and
their appearance may be attributed to the principle of
reversion. But scarcely a single seedling will be found
perfectly to resemble the parent- form ; and this, I believe,
may be accounted for by constantly recurring variability
induced by the conditions of life. I believe in this, be-
cause it has been observed that certain fruit-trees truly
propagate their kind whilst growing on their own roots,
but when grafted on other stocks, and by this process
their natural state is manifestly affected, they pro-
duce seedlings which vary greatly, departing from the
parental type in many chai-acters." Metzger, as stated
in the ninth chapter, found that certain kinds of wheat
brought from Spain and cultivated in Germany, failed
during many years to reproduce themselves truly ; but
that at last, when accustomed to their ne\v conditions,
they ceased to be variable, — that is, they became amena-

*3 Downing, ' Fruits of America,' p. 5 ; Sageret, ' Pom, Pbys.,' pp. 43, 72.

Chap. XII. INHERITANCE. 39

ble to the power of inheritance. Nearly all the plants
which cannot be propagated with any approach to cei*-
tainty by seed, are kinds which have long been propa-
gated by buds, cuttings, offsets, tubers, &c, and* have in
consequence been frequently exposed during their indi-
vidual lives to widely diversified conditions of life. Plants
thus propagated become so variable, that they are subject,
as we have seen in the last chapter, even to bud-variation.
Our domesticated animals, on the other hand, are not
exposed during their individual lives to such extremely
diversified conditions, and are not liable to such extreme
variability ; therefore they do not lose the power of trans-
mitting most of their characteristic features. In the
foregoing remarks on non-inheritance, crossed breeds are
of course excluded, as their diversity mainly depends on
the unequal development of characters derived from either
parent, modified by the principles of reversion and pre-
potency.

Conclusion.

It has, I think, been shown in the early part of this
chapter how strongly new characters of the most diver-
sified nature, whether normal or abnormal, injurious or
beneficial, whether affecting organs of the highest or
most trifling importance, are inherited. Contrary to the
common opinion, it is often sufficient for the inheritance
of some peculiar character, that one parent alone should
possess it, as in most cases in which the rarer anomalies
have been transmitted. But the power of transmission
is extremely variable: in a number of individuals de-
scended from the same parents, and treated in the same
manner, some display this power in a perfect manner, and
in some it is quite deficient ; and for this difference no
reason can be assigned. In some cases the effects of in-
juries or mutilations apparently are inherited; and we
shall see in a future chapter that the effects of the long-
continued use and disuse of parts are certainly inherited.

40 . INHERITANCE. ' Ghap. XIL

Even those characters which are considered the most
fluctuating, such as colour, are with rare exceptions
transmitted much more forcibly than is generally sup-
posed. The wonder, indeed, in all cases is not that any
character should he transmitted, but that the power of
inheritance should ever fail. The checks to inheritance,
as far as we know them, are, firstly, circumstances hos-
tile to the particular character in question; secondly,
conditions of life incessantly inducing fresh variability;
and lastly, the crossing of distinct varieties during some
previous generation, together with reversion or atavism — -
that is, the tendency in the child to resemble its grand-
parents or more remote ancestors instead of its immedi-
ate parents. This latter subject will be fully discussed
in the following chapter.

Chap. XIII.. KE VERSION. 41

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, AVITH INSTINCTS —
OTHER PROXIMATE CAUSES OF REVERSION — LATENT CHARAC-
TERS— SECONDARY SEXUAL CHARACTERS — UNEQUAL DEVELOP-
MENT 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.

The great principle of inheritance to be discussed in this
chapter has been recognised by agriculturists and au-
thors of various nations, -as shown by the scientific term
Atavism, derived from atavus, an ancestor ; by the Eng-
lish terms of Reversion, or Throwing back; by the French
Pas-en-arriere y and by the German Ru-Jc-schlag, or
Hilck-schritt. When the child resembles either grand-
parent more closely than its immediate parents, our at-
fention is not much arrested, though in truth the fact is
highly remarkable ; but when the child resembles some
remote ancestor, or some distant member in a collateral
line, — and we must attribute the latter case to the descent
of all the members from a common progenitor, — Ave feel

42 INHERITANCE. Chap. XIIL

a just degree of astonishment. When one parent alone
dis]:>lays some newly-acquired and generally inheritable
character, and the offspring do not inherit it, the cause
may lie in the other parent having the power of prepotent
transmission. But when both parents are similarly cha-
racterised, and the child doee not, whatever the cause
may be, inherit the character in question, but resembles
its grand-parents, we have one of the simplest cases of
reversion. We continually see another and even more
simple case of atavism, though not generally included
under this head, namely, when the son more closely
resembles his maternal than his paternal grandsire in
some male attribute, as in any peculiarity in the beard of
man, the horns of the bull, the hackles or comb of the
cock, or, as in certain diseases necessarily confined to the
male sex ; for the mother cannot possess or exhibit such
male attributes, yet the child has inherited them, through
her blood, from his maternal grandsire.

The cases of reversion may be divided into two main
classes, which, however, in some instances, blend into
each other; namely, first, those occurring in a variety or
race which has not been crossed, but has lost by variation
some character that it formerly possessed, and which
afterwards reappears. The second class includes all
cases in which a distinguishable individual, sub-variety,
race, or species, has at some former period been crossed
with a distinct form, and a character derived from this
cross, after having disappeared during one or several
generations, suddenly reappears. A third class, differing
only in the manner of reproduction, might be formed to
include all cases of reversion effected by means of buds,
and therefore independent of true or seminal genera-
tion. Perhaps even a fourth class might be instituted*
to include reversions by segments in the same individual
flower or fruit, and in different parts of the body in the
same individual animal as it grows old. But the two
first main classes will be sufficient for" our purpose.

Chap. XIII. REVERSION. 43

Reversion to lost Characters by pure or uncrossed forms.
— Striking instances of this first class of cases were given
in the sixth chapter, namely, of the occasional reappear-
ance, in variously-coloured pure breeds of the pigeon, of
blue birds with all the marks which characterise the
wild Columba livia. Similar cases were given in the
case of the fowl. With the common ass, as Ave now know
that the legs of the wild progenitor are striped, we may
feel assured that the occasional appearance of such stripes
in the domestic animal is a case of simple reversion. But
I shall be compelled to refer again to these cases, and
therefore Avill here pass them over.

The aboriginal Gpecies from which our domesticated
cattle and sheep are descended, no doubt possessed
horns; but several hornless breeds are now well estab-
lished. Yet in these — for instance, in Southdown sheep
— " it is not unusual to find among the male lambs some
with small horns." The horns, which thus occasionally
reappear in other polled breeds, either " grow to the full
" size, or are curiously attached to the skin alone and
hang "loosely down, or drop off." ' The Galloways and
Suffolk cattle have been hornless for the last 100 or 150
years, but a horned calf, with the horn often loosely
attached, is occasionally born.2

There is reason to believe that sheep in their early
domesticated condition were "brown or dingy black;"
but even in the time of David certain flocks were spoken
of as white as snow.^ During the classical period the
sheep of Spain are described by several ancient authors
as being black, red, or tawny.3 At the present day,
notwithstanding the great care which is taken to prevent
it, particoloured lambs and some entirely black are occa-
sionally dropped by our most highly improved and valu-

i Vouatt on Sheep, pp. 20, 234. The gesch. Deutscblands,' b. i. s. 302.

same fact of loose horns occasionally ap- 3 Youatt on Cattle, pp. 155, 174.

pearing in hornless breeds has been ob- 3 Youatt on Sheep, 1S3S, pp. 17, 145.
served in Germany : Dechstein, ' Natur-

44 INHERITANCE. Chap. XIIL

ed breeds, such as the Southdowns. Since the time of
the famous Bakewell, during the last century, the
Leicester sheep have been bred with the most scrupukms
care; yet occasionally grey-faced, or black-spotted, or
wholly black lambs appear.* This occurs still more
frequently with the less improved breeds, such as the
Nbrfolks.5 As bearing on this tendency in sheep to
revert to dark colours, I may state (though in doing so I
trench on the reversion of crossed breeds, and likewise
on the subject of prepotency) that the Rev. "YV. D. Fox
was informed that seven white Southdown ewes were
put to a so-called Spanish ram, which had two small
black spots on his sides, and they produced thirteen
lambs, all perfectly black. Mr. Fox believes that this
ram belonged to a breed which he has himself kept, and
which is always spotted with black and white ; and he
finds that Leicester sheep crossed by rams of this breed
always produce black lambs : he has gone on recrossing
these crossed sheep with pure white Leicesters during
three successive generations, but always with the same
result. Mr. Fox was also told by the friend from whom
the spotted breed was procured, that he likewise had
gone on for six or seven generations crossing with white
sheep, but still black lambs were invariably produced.

Similar facts could be given with respect to tailless
breeds of various animals. For instance, Mr. Hewitt8
states that chickens bred from some Rumpless fowls,
which were reckoned so good that they won a prize at an
exhibition, " in a considerable number of instances were
furnished with fully developed tail-feathers." On inquiry,
the original breeder of these fowls stated that, from the
time he had first kept them, they had often produced

* I have been informed of this fact 1849, p. 395.
through the Rev. W. D. Fox. on the 5 Youatt, pp. 19, 234.

excellent authority of Mr. Wilraot : see, « ' The Poultry Book,' by Mr. Teget-

also, remarks on this subject in an ori- meier, 1S66, p. 231.
ginai article in the ' Quarterly Review,'

Our. XIH. REVERSION. 45

fowls furnished with tails ; but that these latter would
again reproduce rumpless chickens.

Analogous cases of reversion occur in the vegetable
kingdom ; thus " from seeds gathered from the finest cul-
tivated varieties of Heartsease ( Viola tricolor), plants
perfectly wild both in their foliage and their flowers are
frequently produced ;" T but the reversion in this instance
is not to a very ancient period, for the best existing vari-
eties of the heartsease are of comparatively modern ori-
gin. With most of our cultivated vegetables there is
some tendency to reversion to what is known to be, or
may be presumed to be, their aboriginal state ; and this
would be more evident if gardeners did not generally
look over their beds of seedlings, and pull up the false
plants or " rogues" as they are called. It has already
been remarked, that some few seedling apples and. pears
generally resemble, but apparently are not identical with,
the wild trees from which they are descended. In our
turnip8 and carrot-beds a few plants often " break" — that
is, flower too soon ; and their roots are generally found
to be hard and stringy, as in the parent-species. By the
aid of a little selection, carried on during a few genera-
tions, most of our cultivated plants could probably be
brought back, without any great change in their condi-
tions of life, to a wild or nearly wild condition: Mr.
Buckman has effected this with the parsnip ; 9 and Mr.
Hewett C. Watson, as he informs me, selected, during
three generations, "the most diverging plants of Scotch
kail, perhaps one of the least modified varieties of the
cabbage ; and in the third generation some of the plants
came very close to the forms now established in England
about old castle-walls, and called indigenous."

T Loudon's ' Gard. Mag.,' vol. x., 1534. sure5 me that this sometimes occurs.
p. 390 : a nurseryman, with much expe- 8 ' Gardener's Chron.,' 1S55, p. 777.

rience on this subject, has likewise as- 9 Ibid., 1SG2, p. 721.

46 INHERITANCE. Chip. Xllf.

Reversion in Animals and Plants lohich have run
wild. — In the cases hitherto considered, the reverting an-
imals and plants have not been exposed to any great or
abrupt change in their conditions of life which could
have induced this tendency ; but it is very different with
animals and plants which have become feral or run wild.
It has been repeatedly asserted in the most positive man-
ner, by various authors, that feral animals and plants inva-
riably return to their primitive specific type. It is curi-
ous on what little evidence this belief rests. Many of our
domesticated animals could not subsist in a wild state ;
thus, the more highly improved breeds of the pigeon will
not " field" or search for their own food. Sheep have
never become feral, and would be destroyed by almost
every beast of prey. In several cases we<lo not know the
aboriginal parent-species, and cannot possibly tell whe-
ther or not there has been any close degree of reversion.
It is not known in any instance what variety was first
turned out ; several varieties have probably in some cases
run wild, and their crossing alone would tend to oblite-
rate their proper character. Our domesticated animals
and plants, when they run wild, must always be ex-
posed to new conditions of life, for, as Mr. Wallace10 has-
well remarked, they have to obtain their own food, and
are exposed to competition with the native productions.
Under these circumstances, if our domesticated animals
did not undergo change of some kind, the result would
be quite opposed to the conclusions arrived at in this
work. Nevertheless, I do not doubt that the simple fact
of animals and plants becoming feral, does cause some
tendency to reversion to the primitive state; though this
tendency has been much exaggerated by some authors.

I will briefly run through the recorded cases. With neither horses
nor cattle is the primitive stock known ; and it has been shown in

:o See some excellent remarks on this subject by Mr. Wallace, 'Journal Proc. Linn.
Soc.,' 1858, vol. Ui. p. 60.

Cup. XIII. REVERSION. 47

former chapters that they have assumed different colours in dif-
ferent countries. Thus the horses which have run wild in South
America are generally brownish-hay, and in the East dun-coloured ;
their heads have become larger and coarser, and this may be due to
reversion. No careful description has been given of the feral goat.
Dogs which have run wild in various countries have hardly any-
where assumed a uniform character ; 'but they are probably de-
scended from several domestic races, and aboriginally from seve-
ral distinct species. Feral cats, both in Europe and La Plata, are
regularly striped ; in some cases they have grown to an unusually
large size, but do not differ from the domestic animal in any other
character. When variously-colored tame rabbits are turned out in
Europe, they generally reacquire the coloring of the wild animal ;
there can be no doubt that this does really occur, but we should
remember that oddly-coloured and conspicuous animals would suf-
fer much from beasts of prey and from being easily shot ; this at
least was the opinion of a gentleman who tried to stock his woods
with a nearly white variety ; and when thus destroyed, they would
in truth be supplanted by, instead of being transformed into, the
common rabbit. We have seen that the feral rabbits of Jamaica,
and especially of Porto Santo, have assumed new colours and other
new characters. The "best known case of reversion, and that on
which the widely-spread belief in its universality apparently rests,
is that of piffs. These animals have run wild in the West Indies,
South America, and the Falkland Islands, and have everywhere
acquired the dark colour, the thick bristles, and great tusks of the
wild boar ; and the young have reacquired longitudinal stripes.
But even in the case of the pig, Roulin describes the half -wild
animals in different parts of South America as differing in several
respects. In Louisiana the pig11 has run wild, and is said to differ
a little in form, and much in colour, from the domestic animal, yet
does not closely resemble the wild boar of Europe. With pigeons
and fowls,12 it is not known what variety was first turned out, nor
what character the feral birds have assumed. The guinea-fowl in

11 Dureau de la Malle, in ' Comptes become modified in form and voice. The
RenJus,' torn, xli., 1855, p. SOT. From account is so meagre and vague that it
the statements above given, the author did not appear to me worth copying;
concludes that the wild pigs of Louisi- but I now find that Dureau de la Malle
ana are not descended from the Euro- ('Comptes Rendus,' torn, xli., 1S55, p.
pean Sun scrofa. 690) advances this as a good instance

12 Capt. W. Allen, in his ' Expedition of reversion to the primitive stock, and
to the Niger,' states that fowls have run as confirmatory of a still more vague
wild on the island of Annobon, and have statement in classical times by Varro.

48 INHERITANCE. Chap. XIII.

tlie West Indies, when feral, seems to vary more than in the do-
mesticated state.

With respect to plants run wild, Dr. Hooker 13 has strongly in-
sisted on what slight evidence the common belief in their power of
reversion rests. Godron " describes wild turnips, carrots, and ce-
lery ; but these plants in their cultivated state hardly differ from
their wild prototypes, except in the succulency and enlargement of
certain parts, — characters which would be surely lost by plants
growing in a poor soil and struggling with other plants. No cul-
tivated plant has run wild on so enormous a scale as the cardoon
(Cynara carduneulus) in La Plata. Every botanist who has seen it
growing there, in vast beds, as high as a horse's back, has been
struck with its peculiar appearance ; but whether it differs in any
important point from the cultivated Spanish form, which is said
not to be prickly like its American descendant, or whether it differs
from the wild Mediterranean species, which is said not to be social,
I do not know.

Reversion to Characters derived from a Cross, in the
case of Sub-varieties, Races, and Species. — When an indi-
vidual having some recognizable peculiarity unites with
another of the same sub-variety, not having the peculiar-
ity in question, it often reappears in the descendants after
an interval of several generations. Every one must have
noticed, or heard from old people of children closely re-
sembling in appearance or mental disposition, or in so
small and complex a character as expression, one of their
grandparents, or some more distant collateral relation.
Very many anomalies of structure and diseases,16 of
which instances have been given in the last Chapter,
have come into a family from one parent, and have re-
appeared in the progeny after passing over two or three
generations. The following case has been communicated
to me on good authority, and may, I believe, be fully
trusted: a pointer-bitch -produced seven puppies; four
were marked with blue and white, which is so unusual

15 ' Flora of Australia,' 1359, Intro- in the ' British and Foreign Med.-Chirurg.
duct., p. ix. Review,' April and July, 1863, pp. 443,

I* ' De l'Espece,' torn. ii. pp. 54, 53, 6a. 18S.

16 Mr. Sedgwick gives many instances

Chap. XIII.

REVERSION. 49

a colour with pointers that she was thought to have
played false with one of the greyhounds, and the whole
litter was condemned ; but the gamekeeper was permit-
ted to save one as a curiosity. Two years afterwards a
friend of the owner saw the young dog, and declared
that he was the image of his old pointei'-bitch Sappho,
the only blue and white pointer of pure descent which
he had ever seen. This led to close inquiry, and it was
proved that he was the great-great-grandson of Sappho ;
so that, according to the common expression, he had only
l-16th of her blood in his veins. Here it can hardly be
doubted that a character derived from a cross with an
individual of the same variety reappeared after passing
over three generations.

When two distinct races are crossed, it is notorious
that the tendency in the offspring to revert to one or
both parent-forms is strong, and endures for many genera-
tions. I have myself seen the clearest evidence of this
in crossed pigeons and with various plants. Mr. Sidney18
states that, in a litter of Essex pigs, two young ones ap-
peared which were the image of the Berkshire boar that
had been used twenty-eight years before in giving size
and constitution to the breed. I observed in the farm-
yard at Betley Hall some fowls showing a strong like-
ness to the Malay breed, and was told by Mr. Toilet that
he had forty years before crossed his birds with Malays ;
and that, though he had at first attempted to get rid of
this strain, he had subsequently given up the attempt in
despair, as the Malay character would reappear.

This strong tendency in crossed breeds to revert has
given rise to endless discussions in how many genera-
tions after a single cross, either with a distinct breed or
merely with an inferior animal, the breed may be con-
sidered as pure, and free from all danger of reversion.
No one supposes that less than three generations suffices,

» In his edit, of 'Youatt on the Pig,' 1860, p. 27.

50 INHERITANCE. Chap. XIII

and most breeders think that six, seven, or eight are
necessary, and some go to still greater lengths.17 But
neither in the case of a breed which has been contami-
nated by a single cross, nor when, in the attempt to form
an intermediate breed, half-bred animals have been
matched together during many generations, can any rule
be laid down how soon the tendency to reversion will be
obliterated. It depends on the difference in the strength
or prepotency of transmission in the two parent-forms,
on their actual amount of difference, and on the nature of
the conditions of life to which the crossed offspring are
exposed. But we must be careful not to confound these
cases of reversion to characters gained from a cross, with
those given under the first class, in which characters
originally common to both parents, but lost at some
former period, reappear ; for such characters may recur
after an almost indefinite number of generations.

The law of reversion is equally powerful with hybrids,
when they are sufficiently fertile to breed together, or
when they are repeatedly crossed with either pure parent-
form, as with mongrels. It is not necessary to give in-
stances, for in the case of plants almost every one who
lias worked on this subject from the time of Kolreuter
to the present day has insisted on this tendency. Gart-
ner has recorded some good instances ; but no one has
given more striking cases than Xaudin.18 The tendency
differs in degree or strength in different groups, and part-
ly depends, as we shall presently see, on the fact of the
parent-plants having been long cultivated. Although the
tendency to reversion is extremely general with nearly
all mongrels and hybrids, it cannot be considered as in-

17 Dr. P. Lucas, 'Hered. Nat.,' torn. ii. Fortsetzung,' 1766, s. 53, 59 ; and in his
pp. 314, S92 : see a good practical article well-known ' Memoirs on Lavatera and
on this subject in 'Gard. Chronicle,'l 856, Jalapa.' Gartner, ' Bastarderzeugung,'
p. 620. I could add avast number of re- s. 437, 441, Ac Naudin, in his 'Re-
ferences, but they would be superfluous. cherches sur l'Hybridite, Nouvelles Ar-

18 Kolreuter gives cases in his 'Dritte chives du Museum,' torn. i. p. 25.

Chap. Xffl. KEVEKSIOIS". 51

variably characteristic of them ; there is, also, reason to
believe that it may be mastered by long-continued selec-
tion ; but these subjects will more properly be discussed
in a future chapter on Crossing. From what we see of
the power and scope of reversion, both in pure races and
when varieties or species are crossed, we may infer that
characters of almost every kind are capable of reappear-
ance after having been lost for a great length of time.
But it does not follow from this that in each {particular
case certain characters will reappear : for instance, this
will not occur when a race is crossed with another en-
dowed with prepotency of transmission. In some few
cases the power of reversion wholly fails, without our be-
ing able to assign any cause for the failure : thus it has
been stated that in a French family in which 85 out of
above 600 members, during six generations, had been
subject to night-blindness, "there has not been a single
example of this affection in the children of parents who
were themselves free from it."19

Reversion through Bud-propagation — Partial Rever-
sion, by segments hi the same flower or fruit, or in differ-
ent p>arts of the body in the same individual animal. — In
the eleventh chapter, many cases of reversion by buds,
independently of seminal generation, were given — as
when a leaf-bud on a variegated, curled, or laciniated
variety suddenly reassumes its proper character ; or as
when a Provence-rose appears on a moss-rose, or a peach
on a nectarine-tree. In some of these cases only half the
flower or fruit, or a smaller segment, or mere stripes, re-
assumed their former character; and here we have with
buds reversion by segments. Vilmorin20 has also recorded

19 Quoted by Mr. Sedgwick in 'Med.- with thickened joints were transmitted to

Chirnrg. Review,' April, 1861, p. 4S5. several members during fi'.-e generations;

Dr. H. Dobell, in ' Med.-Chirurg. Trans- but when the blemish once disappeared

actions,' vol. xlvi., gives an analogous it never reappeared,

case, in which, in a large family, fingers 2« Verlot, ' Des Variet6s,' 1SG5, p. 63.

52 ESrHEEITANCE. Chap. xni.

several cases with plants derived from seed, of flowei's
reverting by stripes or blotches to their primitive colours :
he states that in all such cases a white or pale-coloured
variety must first be formed, and, when this is propagat-
ed for a length of time by seed, striped seedlings occasion-
ally make their appearance ; and these can afterwards by
care be multiplied by seed.

The stripes and segments just referred to are not due,
as far as is known, to reversion to characters derived
from a cross, but to characters lost by variation. These
cases, however, as Naudin21 insists in his discussion on
disjunction of character, are closely analogous with those
given in the eleventh chapter, in which crossed plants
are known to have produced half-and-half or striped
flowers and fruit, or distinct kinds of flowers on the same
root resembling the two parent-forms. Many piebald
animals probably come under this same head. Such
cases, as we shall see in the chapter on Crossing, appa-
rently result from certain characters not readily blending
together, and, as a consequence of this incapacity for fu-
sion, the offspring either perfectly resemble one of their
two parents, or resemble one parent in one part and the
other parent in another part ; or whilst young are interme-
diate in character, but with advancing age revert wholly
or by segments to either pai-ent-form, or to both. Thus
young trees of the Cytisus adami are intermediate in
foliage and flowers between the two parent-forms ; but
When older the buds continually revert either partially
or wholly to both forms. The cases given in the eleventh
chapter on the changes which occurred during growth
in crossed plants of Tropa3olum, Cereus, Datura, and
Lathyrus are all analogous. As however these plants
are hybrids of the first generation, and as their buds

31 ' Nouvelles Archives du Musoum,1 315) apparently holds a similar opln-
tom. i. p. 25. Alex. Braun (in his ion.
' Rejuvenescence,' Ray Sua, 1S58, p.

Chap. XIE KEVERSIOIST. 53

after a time come to resemble their parents and not their
grandparents, these cases do not at first appear to come
under the law of reversion in the ordinary sense of the
word ; nevertheless, as the change is effected through a
succession of bud-generations on the same plant, they
may be thus included.

Analogous facts have been observed in the animal
kingdom, and are more remarkable,, as they occur strict-
ly in the same individual, and not as with plants through
a succession of bud generations. With animals the act
of reversion, if it can be so designated, does not pass
over a true generation, but merely over the early stages
of growth in the same individual. For instance, I cross-
ed several white hens with a black cock, and many
of the chickens were during the first year perfectly
white, but acquired during the second year black feath-
ers ; on the other hand, some of the chickens which were
at first black became during the second year piebald
with white. A great breeder22 says, that a Pencilled
Brahma hen which has any of the blood of the Light
Brahma in her, will " occasionally produce a pullet well
pencilled during the first year, but she will most likely
moult brown on the shoulders and become quite unlike
her original colours in the second year." The same thing
occurs with Light Brahmas if of impure blood. I have
observed exactly similar cases with the crossed offspring
from differently coloured pigeons. But here is a more re-
markable fact : I crossed a turbit, which has a frill formed
by the feathers being reversed on its breast, with a trum-
peter; and one of the young pigeous thus raised showed
at first not a trace of the frill, but, after moulting thrice,
a small yet unmistakably distinct frill appeared on its
breast. According to Girou,23 calves produced from a
red cow by a black bull, or from a black cow by a red

M Sir. Teebay, in the ■ Poultry Book,' 23 Quoted by Hofacker, ' Ueber die

by Mr. Tegetsneler, 1S66, p. 72. Eigenschaften,' &c, s. 98.

54 INHERITANCE. Chap. XIIL

bull, are not rarely born red, and subsequently become
black.

In the foregoing cases, the characters which appear
with advancing age are the result of a cross in the pre-
vious or some former generation ; but in the following
cases, the characters which thus reappear formerly ap-
pertained to the species, and were lost at a more or less
remote epoch. Thus, according to Azara,24 the calves of
a hornless race of cattle which originated in Corrientes,
though at first quite hornless, as they become adult some-
times acquire small, crooked, and loose horns ; and these
in succeeding years occasionally become attached to the
skull. White and black bantams, both of which gene-
rally breed true, sometimes assume as they grow old a
saffron or red plumage. For instance, a first-rate black
bantam has been described, which during three seasons
was perfectly black, but then annually became more and
more red ; and it deserves notice that this tendency to
change, whenever it occurs in a bantam, " is almost cer-
tain to prove hereditary." " The cuckoo or blue-mottled
Dorking cock, when old, is liable to acquire yellow or
orange hackles in place of his proper bluish-grey hack-
les.28 Now, as G alius bankiva is coloured red and or-
ange, and as Dorking fowls and both kinds of bantams
are descended from this species, we can hardly doubt
that the change which occasionally occurs in the plu-
mage of these birds as their age advances, results from
a tendency in the individual to revert to the primitive
type.

Crossing as a direct cause -of Reversion. — It has long
been notorious that hybrids and mongrels often revert to
both or to one of their parent-forms, after an interval of

24 ' Essais Hist. Nat. du Paraguay,' Book,' by Mr. Tegetmeier, 180fi, p. 248.

tom. ii. 1801, p. 372. 2« ' The Poultry Book,' by Tegetmeier,

26 These facts are given on the high 1S66, p. 97.
authority of Mr. Hewitt, in ' The Poultry

Chap. XIII. REVERSION. 55

from two to seven or eight, or according to some autho-
rities even a greater number of generations. But that
the act of crossing in itself gives an impulse towards rever-
sion, as shown by the reappearance of long-lost charac-
ters, has never, I believe, been hitherto proved. The
proof lies in certain peculiarities, which do not character-
ise the immediate parents, and therefore cannot have
been derived from them, frequently appearing in the off-
spring of two breeds when crossed, which peculiarities
never appear, or appear with extreme rarity, in these same
breeds, as long as they are precluded from crossing. As
this conclusion seems to me highly curious and novel, I
will give the evidence in detail.

My attention was first called to this subject, and I was led to
make numerous experiments, by MM. Boitard and Corbie having
stated that, when they crossed certain breeds, pigeons coloured like
the wild C. Uria, or the common dovecot, namely, slaty-blue, with
double black wing-bars, sometimes chequered with black, white
loins, the tail barred with black, with the outer feathers edged with
white, were almost invariably produced. The breeds which I
crossed, and the remarkable results attained, have been fully de-
scribed in the sixth chapter. I selected pigeons, belonging to true
and ancient breeds, which had not a trace of blue, or any of the
above specified marks ; but when crossed, and their mongrels re-
crossed, young birds were continually produced, more or less plainly
coloured slaty-blue, with some or all of the proper characteristic
marks. I may recall to the reader's memory one case, namely, that
of a pigeon, hardly distinguishable from the wild Shetland species,
the grandchild of a red-spot, white fantail, and two black barbs,
from any of which, when purely-bred, the production of a pigeon
coloured like the wild ft licia would have been almost a prodigy.

I was thus led to make the experiments, recorded in the seventh
chapter, on fowls. I selected long-established, pure breeds, in
which there was not a trace of red, yet in several of the mongrels,
feathers of this colour appeared ; and one magnificent bird, the off-
spring of a black Spanish cock and white Silk hen, was coloured al-
most exactly like the wild Gnllns bmtkiva. All who know anything
of the breeding of poultry will admit that tens of thousands of pure
Spanish and of pure white Silk fowls might have been reared with-
out the appearance of a red feather. The fact, given on the autho-

56 INHERITANCE. Chap. XIII.

rity of Mr. Tegetmeier, of the frequent appearance, in mongrel fowls,
of pencilled or transversely-barred feathers, like those common to
many gallinaceous birds, is likewise apparently a case of reversion
to a character formerly possessed by some ancient progenitor of the
family. I owe to the kindness of this same excellent observer the
inspection of some neck-hackles and tail-feathers from a hybrid be-
tween the common fowl and a very distinct species, the Gallus va-
rius ; and these feathers are transversely striped in a conspicuous
manner, with dark metallic blue and grey, a character which could
not have been derived from either immediate parent.

I have been informed by Mr. B. P. Brent, that he crossed a white
Aylesbury drake and a black so-called Labrador duck, both of
which are true breeds, and he obtained a young drake closely like
the mallard (A. boscJias). Of the musk-duck (A. moscliata, Linn.)
there are two sub-breeds, namely, white and slate-coloured ; and
these I am informed breed true, or nearly true. But the Rev. W.
D. Fox tells me that, by putting a white drake to a slate-coloured
duck, black birds, pied with white, like the wild musk-duck, were
always produced.

We have seen in the fourth chapter, that the so-called Himalayan
rabbit, with its snow-white body, black ears, nose, tail, and feet,
breeds perfectly true. This race is known to have been formed by
the union of two varieties of silver-grey rabbits. Now, when a Him-
alayan doe was crossed by a sandy -coloured buck, a silver-grey rab-
bit was produced ; and this is evidently a case of reversion to one of
the parent varieties. The young of the Himalayan rabbit are born
snow-white, and the dark marks do not appear until some time sub-
sequently ; but occasionally young Himalayan rabbits are born of a
light silver-grey, which colour soon disappears ; so that here we
have a trace of reversion, during an early period of fife, to the pa-
rent-varieties, independently of any recent cross.

In the third chapter it was shown that at an ancient period some
breeds of cattle in the wilder parts of Britain were white with dark
ears, and that the cattle now kept half wild in certain parks, and
those which have run quite wild in two distant parts of the world,
are likewise thus coloured. Now, an experienced breeder, Mr. J.
Beasley, of Northamptonshire,27 crossed some carefully selected
West Highland cows with purely-bred shorthorn bulls. The bulls
were red, red and white, or dark roan ; and the Highland cows
were all of a red colour, inclining to a light or yellow shade. But
a considerable number of the offspring — and Mr. Beasley calls at-

87 ' Gardener's Chron. and Agricultural Gazette,' 1866, p. 528

Chap. XIIL EEVEKSION-. 57

tention to this as a remarkable fact — were white, or white with red
cars. Bearing in mind that none of the parents were white, and
that they were purely-bred animals, it is highly probable that here
the offspring reverted, in consequence of the cross, to the colour
either of the aboriginal parent-species or of some ancient and half-
wild parent-breed. The following case, perhaps, comes under the
same head : cows in their natural state have their udders but little
developed, and do not yield nearly so much milk as our domesti-
cated animals. Now there is some reason to believe2" that cross-
bred animals between two kinds, both of which are good milkers,-
such as Alderneys and Shorthorns, often turn out worthless in this
respect.

Iu the chapter on the Horse, reasons were assigned for believing
that the primitive stock was striped and dun-coloured ; and details
were given, showing that in all parts of the world stripes of a dark
colour frequently appear along the spine, across the legs, and on the
shoulders, where they are occasionally double or treble, and even
sometimes on the face and body of horses of all breeds and of all
colours. But the stripes appear most frequently on the various
kinds of duns. They may sometimes plainly be seen on foals, and
subsequently disappear. The dun-colour and the stripes are strong-
ly transmitted when a horse thus characterised is crossed with any
other ; but I was not able to prove that striped duns are generally
produced from the crossing of two distinct breeds, neither of which
are duns, though this does sometimes occur.

The legs of the ass are often striped, and this may be considered
as a reversion to the wild parent form, the Asinus tceniopus of Abys-
sinia,23 which is thus striped. In the domestic animal the stripes
on the shoulder are occasionally double, or forked at the extremity,
as in certain zebrine species. There is reason to believe that the
foal is frequently more plainly striped on the legs than the adult
animal. As with the horse, I have not acquired any distinct evi-
dence that the crossing of differently-coloured varieties of the ass
brings out the stripes.

But now let us turn to the result of crossing the horse and ass.
Although mules are not nearly so numerous in England as asses, I
have seen a much greater number with striped legs, and with the
stripes far more conspicuous than in either parent-form. Such mules
are generally light-coloured, and might be called fallow-duns. The
shoulder-stripe in one instance was deeply forked at the extremity

28 Ibid., I860, p. 343.

"Sclater, in ' Proc. Zoolog. Soc.,' 1362, p. 163.

58 INHERITANCE. Chap. XIII.

and in another instance was double, though united in the middle.
Mr. Martin gives a figure of a Spanish mule with strong zebra-like
marks on its legs,30 and remarks, that mules are particularly liable
to be thus striped on their legs. In South America, according to
Roulin,'1 such stripes are more frequent and conspicuous in the
mule than in the ass. In the United States, Mr. Gosse,32 speaking
of these animals, says, " that in a great number, perhaps in nine
out of every ten, the legs are banded with transverse dark stripes."

Many years ago I saw in the Zoological Gardens a curious triple
hybrid, from a bay mare, by a hybrid from a male ass and female
zebra. This animal when old had hardly any stripes ; but I was
assured by the superintendent, that when young it had shoulder-
stripes, and faint stripes on its flanks and legs. I mention this case
more especially as an instance of the stripes being much plainer
during youth than in old age.

As the zebra has such conspicuously striped legs, it might have
been expected that the hybrids from this animal and the common
ass would have had their legs in some degree striped ; but it ap-
pears from the figures given in Dr. Gray's ' Knowsley Gleanings,'
and still more plainly from that given by Geoffroy and F. Cuvier,33
that the legs are much more conspicuously striped than the rest of
the body ; and this fact is intelligible only on the belief that the
ass aids in giving, through the power of reversion, this character to
its hybrid offspring.

The quagga is banded over the whole front part of its body like a
zebra, but has no stripes on its legs, or mere traces of them. But
in the famous hybrid bred by Lord Morton,34 from a chesnut, near-
ly purely-bred, Arabian mare, by a male quagga, the stripes were
" more strongly defined and darker than those on the legs of the
quagga." The mare was subsequently put to a black Arabian
horse, and bore two colts, both of which, as formerly stated, were
plainly striped on the legs, and one of them likewise had stripes on
the neck and body.

The Asinus Indicus™ is characterised by a spinal stripe, without
shoulder or leg stripes ; but traces of these latter stripes may occa-

so < History of the Horse,' p. 212. 35 Sclater, in ' Proc. Zoolog. Soc.,' 1862,

31 ' Mem. presentes par divers Savans p. 163 : this species is the Ghor-Khur of

& l'Acad. Royale,' torn. vL 1S35, p. 338. N. W. India, and has often been called

32 'Letters from Alabama,' 1859, p. the Hemionus of Pallas. See, also, Mr.

280. BIyth's excellent paper in ' Journ. of

33 ' Hist. Nat. des Mammiferes,' 1820, Asiatic Soc. of Bengal,' vol. xxviii., I860,

torn. i. p. 229.

*4 'Philosoph. Transact.,' 1321, p. 20.

Chap. XIII. REVERSION. 59

sionally be seen even in tlie adult ;30 and Colonel S. Poole, who has
had ample opportunities for observation, informs me that in the foal,
when first born, the head and legs are often striped, but the
shoulder stripe is not so distinct as in the domestic ass; all these
stripes, excepting that along the spine, soon disappear. Now a
hybrid, raised at Knowsley37 from a female of this species by a male
domestic ass, had all four legs transversely and conspicuously
striped, had three short stripes on each shoulder, and had even some
zebra-like stripes on its face ! Dr. Gray informs me that he has
seen a second hybrid of the same parentage similarly striped.

From these facts we see that the crossing of the seve-
ral equine species tends in a marked manner to cause
stripes to appear on various parts of the body, especial-
ly on the legs. As we do not know whether the pri-
mordial parent of the genus was striped, the appearance
of the stripes can only hypothetically be attributed to
reversion. But most persons, after considering the many
undoubted cases of variously coloured marks reappearing
by reversion in crossed pigeons, fowls, ducks, &c, will
come to the same conclusion with respect to the horse-
genus ; and in this case we must admit that the progeni-
tor of the group was striped on the legs, shoulders, face,
and probably over the whole body, like a zebra. If wo
reject this view, the frequent and almost regular appear-
ance of stripes in the several foregoing hybrids is left
without any explanation.

It would appear that with crossed animals a similar
tendency to the recovery of lost characters holds good
even with instincts. There are some breeds of fowls
which are called " everlasting layers," because they have
lost the instinct of incubation ; and so rare is it for them

36 Another species of wild ass, the quoted, and in ' Indian Sporting Review,'

true .4. hemionua or Kiang, which or- 1S56, p. 320; and Col. Hamilton Smith,

dinarily has no shoulder-stripes, is said iu 'Nat. Library, Horses,' p. 31S; and

occasionally to have them ; and these, as ' Diet. Class. d'Hist. Nat.,' torn. iii. p. 5G3.

with the horse and ass, are sometimes 37 Figured in the 'Gleanings from the

double : see Mr. Blyth, in the paper just Knowsl?y Menageries,' by Dr. J. E. Gray.

60 INHERITANCE. Chap. XIII.

to incubate that I have seen notices published in works
on poultry, when hens of such breeds have taken to sit.38
Yet the aboriginal species was of course a good incu-
bator; for with birds in a state of nature hardly any in-
stinct is so strong as this. Now, so many cases have
been recorded of the crossed offspring from two races,
neither of which are incubators, becoming first-rate sit-
ters, that the reappearance of this instinct must be at-
tributed to reversion from crossing. One author goes so
far as to say, " that a cross between two non-sitting vari-
eties almost invariably produces a mongrel that becomes
broody, and sits with remarkable steadiness." 39 Another
author, after giving a striking example, remarks that
the fact can be explained only on the principle that
" two negatives make a positive." It cannot, however,
be maintained that hens produced from a cross between
two non-sitting breeds invariably recover their lost in-
stinct, any more. than that crossed fowls or pigeons inva-
riably recover the red or blue plumage of their prototypes.
I raised several chickens from a Polish hen by a Spanish
cock, — breeds which do not incubate, — and none of the
young hens at first recovered their instinct, and this ap-
peared to afford a -well-marked exception to the forego-
ing rule ; but one of these hens, the only one which was
preserved, in the third year sat well on her eggs and

S8 Cases of both Spanish and Polish cross between Golden and Bfeck Polish

hens sitting are given in the ' Poultry fowls, are " good and steady birds to

Chronicle,' 1855, vol. Hi., p. 477. sit." Mr. B. P. Brent informs me that

39 ' The Poultry Book,' by Mr. Teget- he raised some good sitting hens by
meier, 1S66, pp. 119, 163. The author, crossing Pencilled Hamburgh and Polish
who remarks on the two negatives breeds. A cross-bred bird from a Span-
('Journ. of Hort.,' 1862, p. 325), states ish non-incubating cock and Cochin in-
that two broods were raised from a Span- cubating hen is mentioned in the ' Poul-
ish cock and Silver-pencilled Hamburgh try Chronicle,' vol. iii. p. 13, as an " ex-
hen, neither of which are incubators, and emplary mother." On the other hand,
no less than seven out of eight hens an exceptional case is given in the ' Cot-
in these two broods " showed a perfect tage Gardener,' 1860, p. 388, of a hen
obstinacy in sitting." The Rev. E. S. raised from a Spanish cock and black
Dixon (' Ornamental Poultry,' 1848, p. Polish hen which did not incubate.
200) says that chickens reared from a

Chap. XIII. REVERSION. 61

reared a brood of chickens. So that here we have the
appearance with advancing age of a primitive instinct,
in the same manner as we have seen that the red plu-
mage of the Gallus bankiva is sometimes reacquired by
crossed and purely-bred fowls of various kinds as they
grow old.

The parents of all our domesticated animals were of
course aboriginally wild in disposition ; and when a do-
mesticated species is crossed with a distinct species,
whether this is a domesticated or only tamed animal, the
hybrids are often wild to such a degree, that the fact is
intelligible only on the principle that the cross has caused
a partial return to the primitive disposition.

The Earl of Powis formerly imported some thoroughly
domesticated humped cattle from India, and crossed them
with English breeds, which belong to a distinct species ;
and his agent remarked to me, without any question hav-
ing been asked, how oddly wild the cross-bred animals
were. The European wild boar and the Chinese domes-
ticated pig are almost certainly specifically distinct : Sir
F. Darwin crossed a sow of the latter breed with a wild
Alpine boar which had become extremely tame, but the
young, though having half-domesticated blood in their
veins, Avere " extremely wild in confinement, and would
not eat swill like common English pigs." Mr. Hewitt,
who has had great experience in crossing tame cock-
pheasants with fowls belonging to five breeds, gives as
the character of all " extraordinary wildness ; " 40 but I
have myself seen one exception to this rule. Mr. S. J.
Salter,41 who raised a large number of hybrids from a
bantam-hen by Gallus Sonneratii, states that "all were
exceedingly wild." Mr. TVaterton" bred some wild
ducks from eggs hatched under a common duck, and the

*o • xhe Poultry Book,' by Tegetmeier,' April, p. 277.
1866, pp. 165,167. 42 'Essays on Natural History,' p.

*« 'Natural nistory Review,' 1S63, 197.

62 INHEKITANCE. Chap. XIII.

young were allowed to cross freely both amongst them-
selves and with the tame ducks ; they were " half wild
and half tame ; they came to the windows to be fed, but
still they had a wariness about them quite remarkable."

On the other hand, mules from the horse and ass are
certainly not in the least wild, yet they are notorious for
obstinacy and vice. Mr. Brent, who has crossed canary-
birds with many kinds of finches, has not observed, as
he informs me, that the hybrids were in any way remark-
ably wild. Hybrids are often raised between the com-
mon and musk duck, and I have been assured by three
persons, who have kept these crossed birds, that they
were not wild; but Mr. Garnett43 observed that his
female hybrids exhibited "migratory propensities," of
which there is not a vestige in the common or musk duck.
No case is known of this latter bird having escaped and
become wild in Europe or Asia, except, according to
Pallas, on the Caspian Sea ; and the common domestic
duck only occasionally becomes wild in disti'icts where
large lakes and fens abound. Nevertheless, a large num-
ber of cases have been recorded44 of hybrids from these
two ducks, although so few are reared in comparison
with purely-bred birds of either species, having been shot
in a completely wild state. It is improbable that any of
these hybrids could have acquired their wildness from
the musk-duck having paired with a truly wild duck;
and this is known not to be the case in North America ;
hence we must infer that they have reacquired, through
reversion, their wildness, as well as renewed powers of
flight.

These latter facts remind us of the statements, so fre-

*3 As stated by Mr. Orton, in his vol. v., 1S-45-46, p. 1254) that several

' Physiology of Breeding,' p. 12. have been shot in various parts of Bcl-

44 M. E. de Selys-Longchamps refers gium and Northern France. Audubon

(' Bulletin Acad. Roy. de Bruxelles,1 (' Ornitholog. Biography,' vol. iii. p.

torn. xii. No. 10) to more than seven of 168), speaking of these hybrids, says

these hybrids shot in Switzerland and that, in North America, they " now and

France. M. Deby asserts ('Zoologist,' then wander off and become quite wild."

Chap. XIII. REVERSION. 63

quently made by travellers in all parts of the world, on
the degraded state and savage disposition of crossed races
of man. That many excellent and kind-hearted mulattos
have existed no one will dispute ; and a more mild and
gentle set of men could hardly be found than the inhabi-
tants of the island of Chiloe, who consist of Indians com-
mingled with Spaniards in various proportions. On the
other hand, many years ago, long before I had thought
of the present subject, I was struck with the fact that,
in South America, men of complicated descent between
Negroes, Indians, and Spaniards, seldom had, whatever
the cause might be, a good expression.45 Livingstone, —
and a more unimpeachable authority cannot be quoted, —
after speaking of a half-caste man on the Zambesi, de-
scribed by the Portuguese as a rare monster of inhu-
manity, remarks, "It is unaccountable why half-castes,
such as he, are so much more cruel than the Portuguese,
but such is undoubtedly the case." An inhabitant re-
marked to Livingstone, " God made white men, and God
made black men, but the Devil made half-castes."46 When
two races, both low in the scale, are crossed, the progeny
seems to be ernimently bad. Thus the noble-hearted
Humboldt, who felt none of that prejudice against the
inferior races now so current in England, speaks in strong
terms of the bad and savage disposition of Zambos, or
half-castes between Indians and Negroes; and this con-
clusion has been arrived at by various observers.47 From
these facts we may perhaps infer that the degraded state
of so many half-castes is in part due to reversion to a
primitive and savage condition, induced by the act of
crossing, as well as to the unfavourable moral conditions
under which they generally exist.

48 'Journal of Researches,' 1945, p. 71. 4T Dr. P. Broca, on ' Hybridity In the

4S ' Expedition to the Zambesi,' 1865, Genus Homo,' Eng. translat., l&W, p. 89.
pp. 25, 150.

64 INHERITANCE. Chap. XIII.

Summary on the proximate causes leading to Rever-
sion.— When purely-bred animals or plants reassume
long-lost characters, — when the common ass, for instance,
is born with striped legs, when a pure race of black
or white pigeons throws a slaty-blue bird, or when a cul-
tivated heartsease with large and rounded flowers pro-
duces a seedling with small and elongated flowers, — we
are quite unable to assign any proximate cause. When
animals run wild, the tendency to reversion, which,
though it has been greatly exaggerated, no doubt exists,
is sometimes to a certain extent intelligible. Thus, with
feral pigs, exposure to the weather will probably favour
the growth of the bristles, as is known to be the case
with the hair of other domesticated animals, and through
correlation the tusks will tend to be redeveloped. But
the reappearance of coloured longitudinal stripes on
young feral pigs cannot be attributed to the direct action
of external conditions. In this case, and in many others,
Ave can only say that changed habits of life apparently
have favoured a tendency, inherent or latent in the spe-
cies, to return to the primitive state.

It will be shown in a future chapter that the position
of flowers on the summit of the axis, and the position of
seeds within the capsule, sometimes determine a tendency
towards reversion ; and this apparently depends on the
amount of sap or nutriment which the flower-buds smd
seeds receive. The position, also, of buds, either on
branches or on roots, sometimes determines, as was for-
merly shown, the transmission of the proper character of
the variety, or its reversion to a former state.

We have seen in the last section that when two races
or species are crossed there is the strongest tendency to
the reappearance in the offspring of long-lost characters,
possessed by neither parent nor immediate progenitor.
When two white, or red, or black pigeons, of well-estab-
lished breeds, are united, the offspring are almost sure to
inherit the same colours ; but when differently-coloured

Chap. XIII. EEVEESION. 65

birds are crossed, the opposed forces of inheritance appa-
rently counteract each other, and the tendency which is
inherent in both parents to produce slaty-blue offspring
becomes predominant. So it is in several other cases.
But when, for instance, the ass is crossed with A. Indiciis
or with the horse, — animals which have not striped legs,
— and the hybrids have conspicuous stripes on their legs
and even on their faces, all that can be»said is, that an
inherent tendency to reversion is evolved through some
disturbance in the organisation caused by the act of
crossing.

Another form of reversion is far commoner, indeed is
almost universal with the offspring from a cross, namely,
to the characters proper to either pure parent-form. As a
general rule, crossed offspring in the first generation are
nearly intermediate between their parents, but the grand-
children and succeeding generations continually revert, in
a greater or lesser degree, to one or both of their proge-
nitors. Several authors have maintained that hybrids
and mongrels include all the characters of both parents,
not fused together, but merely mingled in different pro-
portions in different pails of the body ; or, as Naudin48 has
expressed it, a hybrid is a living mosaic-work, in which
the eye cannot distinguish the discordant elements, so
completely are they intermingled. We can hardly doubt
that, in a certain sense, this is true, as when we behold
in a hybrid the elements of both species segregating
themselves into segments in the same flower or fruit, by
a process of self-attraction or self-affinity ; this segre-
gation taking place either by seminal or by bud-jsropa-
gation. Xaudin further believes that the segregation of
the two specific elements or essences is eminently liable
to occur in the male and female rejiroductive matter ; and
he thus explains the almost universal tendency to rever-
sion in successive hybrid generations. For this would

49 'Nouvelles Archives du Museum,' torn. i. p. 151.

66 INHEKITAZSTCE. Chap. XIII.

be the natural result of the union of pollen and ovules, in
both of which the elements of the same species had been
segregated by self-affinity. If, on the other hand, pollen
which included the elements of one species happened to
unite with ovules including the elements of the other spe-
cies, the intermediate or hybrid state would still be
retained, and there would be no reversion. But it would,
as I suspect, belnore correct to say that the elements of
both parent-species exist in every hybrid in a double
state, namely, blended together and completely separate.
How this is possible, and what the term specific essence
or element may be supposed to express, I shall attempt to
show in the hypothetical chapter on pangenesis.

But Naudin's view, as propounded by him, is not
applicable to the reappearance of characters lost long
ago by variation ; and it is hardly applicable to races or
species which, after having been crossed at some former
period with a distinct form, and having since lost all
traces of the cross, nevertheless occasionally yield an in-
dividual which reverts (as in the case of the great-great-
grandchild of the pointer Sappho) to the crossing form.
The most simple case of reversion, namely, of a hybrid or
mongrel to its grandparents, is connected by an almost
perfect series with the extreme case of a purely-bred
race recovering characters which had been lost during
many ages ; and we are thus led to infer that all the cases
must be related by some common bond.

Gartner believed that only those hybrid plants which
are highly sterile exhibit any tendency to reversion to
their parent-forms. It is rash to doubt so good an ob-
server, but this conclusion must I think be an error ; and
it may perhaps be accounted for by the nature of the
genera observed by him, for he admits that the tendency
differs in different genera. The statement is also direct-
ly contradicted by Naudin's observations, and by the no-
torious fact that perfectly fertile mongrels exhibit the

Chap. XIII. REVERSION. 67

tendency in a high degree, — even in a higher degree, ac-
cording to Gartner himself, than hybrids.49

Gartner further states that reversions rarely occur with
hybrid plants raised from species which have not been
cultivated, whilst, with those which have been long cul-
tivated, they are of frequent occurrence. This conclusion
explains a curious discrepancy : Max "Wichura,60 who
worked exclusively on willows, which had not been sub-
jected to culture, never saw an instance of reversion ;
and he goes so far as to suspect that the careful Gartner
had not sufficiently protected his hybrids from the pollen
of the parent-species: Naudin, on the other hand, who
chiefly experimented on cucurbitaceous and other culti-
vated plants, insists more strenuously than any other
author on the tendency to reversion in all hybrids. The
conclusion that the condition of the parent-species, as
affected by culture, is one of the proximate causes lead-
ing to reversion, agrees fairly well with the converse case
of domesticated animals and cultivated plants being
liable to reversion when they become feral ; for in both
cases the organisation or constitution must be disturbed,
though in a very different way.

Finally, we have seen that characters often reappear in
purely-bred races without our being able to assign any
proximate cause ; but when they become feral this is
either indirectly or directly induced by the change in
their conditions of 'life. With cross breeds, the act of
crossing in itself certainly leads to the recovery of long-
lost characters, as well as of those derived from either
parent-form. Changed conditions, consequent on culti-
vation, and the relative position of buds, flowers, and
seeds on the plant, all apparently aid in giving this same
tendency. Reversion may occur either through seminal.

49 ' Bastarderzeugung,' s. 582, 43S, «fcc. marks on this head, see ' Bastarderzeu-
60 ' Die Bastardbefruchtung .... der gung,' s. 474, 5S2.
Weiden,' 1S65, b. 23. For Gartner's re-

68 INHERIT A1STCE. Chap. XIII.

or bad generation, generally at birth, but sometimes only
with an advance of age. Segments or portions of the
individual may alone be thus affected. That a being
should be born resembling in certain characters an an-
cestor removed by two or three, and in some cases by
hundreds or even thousands of generations, is assuredly
a wonderful fact. In these cases the child is commonly
said to inherit such characters directly from its grand-
parents or more remote ancestors. But this view is hardly
conceivable. If, however, Ave suppose that every cha-
racter is derived exclusively from the father or mother,
but that many characters lie latent in both parents dur-
ing a long succession of generations, the foregoing facts
are intelligible. In what manner characters may be con-
ceived to lie latent, will be considered in a future chapter
to which I have lately alluded.

Latent Characters. — But I must explain what is meant
by characters lying latent. The most obvious illustra-
tion is afforded by secondary sexual characters. In every
female all the secondary male characters, and in every
male all the secondary female characters, apparently ex-
ist in a latent state, ready to be evolved under certain
conditions. It is well known that a large number of fe-
male birds, such as fowls, various pheasants, partridges,
peahens, ducks, &c, when old or diseased, or when ope-
rated on, partly assume the secondary male charactei*s of
their species. In the case of the hen-pheasant this has
been observed to occur far more frequently during certain
seasons than during others.51 A duck ten years old has
been known to assume both the perfect winter and sum-
mer plumage of the drake.62 Waterton53 gives a curious
case of a hen which had ceased laying, and had assumed

61 Varrell, 'Phil. Transact.,' 1S27. p. 52 ' Archiv. Skand. Peitrage zur Na-

263 ; Dr. Hamilton, in ' Proc. Zoolog. turgesch.,' viii. s. 897-413.
Soc.,' 1862, p. 23. H In his ' Essays on Nat. Hist.,' 1838.

Chap. XIII.

reversion. 69

the plumage, voice, spurs, and warlike disposition of the
cock; when opposed to an enemy she would erect her
hackles and show fight. Thus every character, even to
the instinct and manner of lighting, must have lain dor-
mant in this hen as long as her ovaria continued to act.
The females of two kinds of deer, when old, have been
known to acquire horns ; and, as Hunter has remarked, we
see something of an analogous nature in the human species.
On the other hand, with male animals, it is notorious
that the secondary sexual characters are more or less
completely lost when they are subjected to castration.
Thus, if the operation be performed on a young cock, he
never, as Yarrell states, crows again ; the comb, wattles,
and spurs do not grow to their full size, and the hackles
assume an intermediate appearance between true hackles
and the feathers of the hen. Cases are recorded of con-
finement alone causing analogous results. But characters
properly confined to the female are likewise acquired ;
the capon takes to sitting on eggs, and will bring up
chickens ; and what is more curious, the utterly sterile
male hybrids from the pheasant and the fowl act in the
same manner, " their delight being to watch when the
hens leave their nests, and to take on themselves the of-
fice of a sitter." 64 That admirable observer Reaumur 65
asserts that a cock, by being long confined in solitude
and darkness, can be taught to take charge of young
chickens ; he then utters a peculiar cry, and retains dur-
ing his whole life this newly acquired maternal instinct.
The many well-ascertained cases of various male mam-
mals giving milk, show that their rudimentary mammary
glands retain this capacity in a latent condition.

Mr. Hewitt gives analogous cases with Aristotle was well aware of the change in

hen-pheasants in ' Journal of Horticul- mental disposition in old hens. The case

ture,' July 12, 1864, p. 37. Isidore of the female deer acquiring horns is

Geoffroy Saint Hilalre, in his ' Essais de given at p. 513.

Zoolog. Gen.' (suites a Buffon, 1S4'2, pp. , « ' Cottage Gardener,' 1860, p. 379.

496-518), has collected such cases in ten 65 ' Art de faire Eclorre,' &c, 1749,

different kinds of birds. It appears that torn. ii. p. 8.

70 LNHEKITANCE. Chap. XIII.

We thus see that in many, probably in all cases, the
secondary characters of each sex lie dormant or latent in
the opposite sex, ready to be evolved under peculiar cir-
cumstances. We can thus understand how, for instance,
it is possible for a good milking cow to transmit her good
qualities through her male offspring to future generations ;
for we may confidently believe that these qualities are
present, though latent, in the males of each generation.
So it is with the game-cock, who can transmit his superi-
ority in courage and vigour through his female to his
male offspring ; and with man it is known56 that diseases,
such as hydrocele, necessarily confined to the male sex,
can be transmitted through the female to the grandson.
Such cases as these offer, as was remarked at the com-
mencement of this chapter, the simplest possible examples
of reversion ; and they are intelligible on the belief that
characters common to the grandparent and grandchild of
the same sex are present, though latent, in the intermedi-
ate parent of the opposite sex.

The subject of latent characters is so important, as wo
shall see in a future chapter, that I will give another illus-
tration. Many animals have the right and left sides of
their body unequally developed : this is well known to be
the case with flat-fish, in which the one side differs in
thickness and colour, and in the shape of the fins, from
the other ; and during the growth of the young fish one
eye actually travels, as shown by Steenstrup, from the
lower to the upper surface." In most flat-fishes the left
is the blind side, but in some it is the right ; though in
both cases " wrong fishes," which are developed in a re-
versed manner to what is usual, occasionally occur, and
in Platessa flesus the right or left side* is indifferently de-
veloped, the one as often as the other. With gasteropods

56 Sir H. Holland, ' Medical Notes and^ Views on the Obliquity of Flounders :
Reflections,' 3rd edit,, 1855, p. 31. ' Annals and Mag. of Nat. Hist.,' May,

67 Prof. Thomson on Steenstrup's 1SG5, p. 361.

Chap. XIII. REVERSION. 1 1

or shell-fish, the right and left sides are extremely une-
qual ; the far greater number of species are dextral, with
rare and occasional reversals of development, and some
few are normally sinistral ; but certain species of Bulimus,
and many Achatinella?,68 are as often sinistral as dextral.
I will give an analogous case in the great Articulate
kingdom: the two sides of Verruca69 are so wonderfully
unlike, that without careful dissection it is extremely dif-
ficult to recognise the corresponding parts on the oppo-
site sides of the body ; yet it is apparently a mere matter
of chance whether it be the right or the left side that un-
dergoes so singular an amount of change. One plant is
known to me60 in which the flower, according as it stands
on the one or other side of the spike, is unequally devel-
oped. In all the foregoing cases the two sides of the
animal are perfectly symmetrical at an early period of
groAvth. Now, whenever a species is as liable to be un-
equally developed on the one side as on the other side, Ave
may infer that the capacity for such development is pre-
sent, though latent, in the undevelojied side. And as a
reversal of development occasionally occurs in animals of
many kinds, this latent capacity is probably very common.
The best yet simplest instances of characters lying
dormant are, perhaps, those previously given, in which
chickens and young pigeons, raised from a cross between
differently coloured birds, are at first of one colour, but
in a year or two acquire feathers of the colour of the
other parent ; for in this case the tendency to a change
of plumage is clearly latent in the young bird. So it is
with hornless breeds of cattle, some of which acquire,
rs they grow old, small horns. Purely bred black and
white bantams, and some other fowls, occasionally as-

59 Dr. E. von Martens, in ' Annals and ment of the thoracic limbs on the right

Mag. of Nat. Hist.,' March, 1866, p. 209. and left sides in the higher crustaceans.

69 Darwin, 'Balanid»,' Ray Soc, 1S54, 60 Mormodes ignea : Darwin, 'Fertili-

p. 490 : see also the appended remarks zation of Orchids,' 1862, p. 251.
on the apparently capricious develop-

*72 INHERITANCE. Chap. XIII.

Burae, with advancing years, the red feathers of the pa-
rent-species. I will here add a somewhat different case,
as it connects in a striking manner latent characters of
two classes. Mr. Hewitt61 possessed an excellent Se-
bright gold-laced hen bantam, which, as she became old,
grew diseased in her ovaria, and assumed male charac-
ters. In this breed the males resemble the females in
all respects except in their combs, wattles, spurs, and in-
stincts ; hence it might have been expected that the dis-
eased hen would have assumed only those masculine
characters which are proper to the breed, but she ac-
quired, in addition, well-arched tail sickle-feathers quite
a foot in length, saddle-feathers on the loins, and hackles
on the neck, — ornaments which, as Mr. Hewitt remarks,
" would be held as abominable in this breed." The Se-
bright bantam is known62 to have originated about the
year 1800 from a cross between a common bantam and
a Polish fowl, recrossed by a hen-tailed bantam, and
carefully selected ; hence there can hardly be a doubt
that the sickle-feathers and hackles which appeared in
the old hen were derived from the Polish fowl or com-
mon bantam ; and we thus see that not only certain mas-
culine characters proper to the Sebright bantam, but
other masculine characters derived from the first proge-
nitors of the breed, removed by a period of about sixty
years, were lying latent in this hen-bird, ready to be
evolved as soon as her ovaria became diseased.

From these several fticts it must be admitted that cer-
tain characters, capacities, and instincts may lie latent
in an individual, and even in a succession of individuals,
without our being able to detect the least signs of their
presence. We have already seen that the transmission

81 ' Journal of Horticulture,' July, Tegetmeier.

1864, p. 38. I have had the opportu- 62 ' The Poultry Book,' by Mr. Teget-

nity of examining fliese remarkable meier, 1S66, p. 241.
feathers through the kindness of Mr.

Chap. XIII. REVERSION. T3

of a character from the grandparent to the grandchild,
with its apparent omission in the intermediate parent of
the opposite sex, becomes simple on this view. When
fowls, pigeons, or cattle of different colours are crossed,
and their offspring change colour as they grow old, or
when the crossed turbit acquired the characteristic frill
alter its third moult, or when purely-bred bantams par-
tially assume the red plumage of their prototype, we
cannot doubt that these qualities were from the first pre-
sent, though latent, in the individual animal, like the
characters of a moth in the caterpillar. Now, if these
animals had produced offspring before they had acquired
with advancing age their new characters, nothing is
more probable than that they would have transmitted
them to some of their offspring, which in this case would
in appearance have received such chai*acters from their
grandparents or more distant progenitors. We should
then have had a case of reversion, that is, of the reappear-
ance in the child of an ancestral character, actually pre-
sent, though during youth completely latent, in the
parent ; and this we may safely conclude is what occurs
with reversions of all kinds to progenitors however re-
mote.

This view of the latency in each generation of all the
characters which appear through reversion, is also sup-
ported by their actual presence in some cases during
early youth alone, or by their more frequent appearance
and greater distinctness at this age than during maturity.
We have seen that this is often the case with the stripes
on the legs and faces of the several species of the horse-
genus. The Himalayan rabbit, when crossed, sometimes
produces offspring which revert to the parent silver-grey
breed, and we have seen that in purely bred animals pale-
grey fur occasionally reappears during early youth. Black
cats, wo may feel assured, would occasionally produce by
reversion tabbies; and on young black kittens, with a

74 INHEEITAISTCE. Chap. XIII.

pedigree c3 known to have been long pure, faint traces of
stripes may almost always be seen which afterwards dis-
appear. Hornless Suffolk cattle occasionally produce by
reversion horned animals ; and Youatt " asserts that even
in hornless individuals " the rudiment of a horn may be
often felt at an early age."

No doubt it appears at first sight in the highest degree
improbable that in every horse of every generation there
should be a latent capacity and tendency to produce stripes,
though these may not appear once in a thousand genera-
tions ; that in every white, black, or other coloured pigeon,
which may have transmitted its proper colour during cen-
turies, there should be a latent capacity in the plumage to
become blue and to be marked with certain characteristic
bars ; that in every child in a six-fingered family there
should be the capacity for the production of an additional
digit ; and so in other cases. Nevertheless there is no
more inherent improbability in this being the case than
in a useless and rudimentary organ, or even in only a
tendency to the production of a rudimentary organ, being
inherited during millions of generations, as is well known
to occur with a multitude of organic beings. There is no
more inherent improbability in each domestic pig, during
a thousand generations, retaining the capacity and ten-
dency to develop great tusks under fitting conditions,
than in the young calf having retained for an indefinite
number of generations rudimentary incisor teeth, which
never protrude through the gums.

I shall give at the end of the next chapter a summary
of the three preceding chapters; but as isolated and
striking cases of reversion have here been chiefly insisted
on, I wish to guard the reader against supposing that
reversion is due to some rare or accidental combination
of circumstances. When a character, lost during hun-

88 Carl Vogt, ' Lectures on Man,' Eng. tvanslat., 1864, p. 411.
*« On Cattle, p. 174.

Chap. XIII.

REVERSION. 75

drcds of meliorations, suddenly reappears, no doubt some
such combination must occur ; but reversions may be con-
stantly observed, at least to the immediately preceding
generations, in the offspring of most unions. This has
been universally recognised in the case of hybrids and
mongrels, but it has been recognised simply from the dif-
ference between the united forms rendering the resem-
blance of the offspring to their grandparents or more
remote progenitors of easy detection. Reversion is like-
wise almost invariably the rule, as Mr. Sedgwick has
shown, with certain diseases. Hence we must conclude
that a tendency to this peculiar form of transmission is an
integral part of the general law of inheritance.

3fonstrositie$. — A larcje number of monstrous growths
and of lesser anomalies are admitted by every one to be
due to an arrest of development, that is to the persist-
ence of an embryonic condition. If every horse or ass
had striped legs whilst young, the stripes which oc-
casionally appear on these animals when adult would
have to be considered as due to the anomalous retention
of an early character, and not as due to reversion.
Now, the leg-stripes in the horse-genus, and some other
characters in analogous cases, are apt to occur during
early youth and then to disappear; thus the persistence
of early characters and reversion are brought into close
connexion.

But many monstrosities can hardly be considered as
the result of an arrest of development ; for parts of
which no trace can be detected in the embryo, but
which occur in other members of the same class of ani-
mals or plants, occasionally appear, and these may prob-
ably with truth be attributed to reversion. For instance :
supernumerary mamma?, capable of secreting milk, are
not extremely rare in women ; and as many as five have
been observed. When four are developed, they are
generally arranged symmetrically on each side of the

76 INHERITANCE. Ciur. Xiri.

chest; and in one instance a woman (the daughter of
another with supernumerary mamma?) had one mamma,
which yielded milk, developed in the inguinal region.
This latter case, when we remember the position of the
mammae in some of the lower animals on both the chest
and inguinal region, is highly remarkable, and leads
to the belief that in all cases the additional mammae
in woman are due to reversion. The facts given in the
last chapter on the tendency in supernumerary digits
to regrowth after amputation, indicate their relation
to the digits of the lower vertebrate animals, and lead
to the suspicion that their appearance may in some
manner be connected with reversion. But I shall have
to recur, in the chapter on pangenesis, to the abnormal
multiplication of organs, and likewise to their occasional
transposition. The occasional development in man of
the coccygeal vertebra? into a short and free tail, though
it thus becomes in one. sense more perfectly developed,
may at the same time be considered as an arrest of de-
velopment, and as a case of reversion. The greater fre-
quency of a monstrous kind of proboscis in the pig than
in any other mammal, considering the position of the
pig in the mammalian series, has likewise been attri-
buted, perhaps truly, to reversion.65

When flowers which are properly irregular in structure become
regular or peloric, the change is generally looked at by botanists
as a return to the primitive state. But Dr. Maxwell Masters,68 who
has ably discussed this subject, remarks that when, for instance,
all the sepals of a Tropaeolum become green and of the same shape,
instead of being coloured with one aloue prolonged into a spur, or
when all the petals of a Linaria become simple and regular, such
cases may be due merely to an arrest of development ; for in these
flowers all the organs during their earliest condition are symme-

65 Isid. Oeoffroy St. Hilaire, ' Des Ano- p. 25S. See also his Lecture, Royal

malies,' tom. Hi. p. 353. With respect Institution, March 16, 1S60. On same

to the mamma? in women, see tom. i. p. subject, see Moquin-Tandon, ' Elements

710. de Teratologic,' 1S41, pp. 1S±, 352:

•• 'Natural Hist. Review,' April, 1S63,

Chap. XIII. REVERSION. 77

trical, and, if arrested at this stage of growth, they would not
become irregular. If, moreover, the arrest were to take place
at a still earlier period of development, the result would be a sim-
ple tuft of green leaves ; and no one probably would call this a
case of reversion. Dr. Masters designates the cases first alluded
to as regular peloria ; and others, in which all the corresponding
parts assume a similar form of irregularity, as when all the petals
in a Linaria become spurred, as irregular peloria. We have no
right to attribute these latter cases to reversion, until it can be
shown to be probable that the parent-form, for instance, of
the genus Linaria had had all its petals spurred ; for a change
of this nature might result from the spreading of an anomalous
structure, in accordance with the law, to be discussed in a future
chapter, of homologous parts tending to vary in the same manner.
But as both forms of peloria frequently occur on the same indivi-
dual plant of the Linaria,67 they probably stand in some close
relation to each other. On the doctrine that peloria is simply
the resuli of an arrest of development, it is difficult to understand
how an organ arrested at a very early period of growth should
acquire its full functional perfection : — how a petal, supposed to
be thus arrested, should acquire its brilliant colours, and serve as
an envelope to the flower, or a stamen produce efficient pollen ;
yet this occurs with many peloric flowers. That pelorism is not
due to mere chance variability, but either to an arrest of develop-
ment or to reversion, we may infer from an observation made by
Ch. Morren,88 namely, that families which have irregular flowers
often " return by these monstrous growths to their regular form ;
whilst we never see a regular flower realize the structure of an
irregular one."

Some flowers have almost certainly become more or less com-
pletely peloric through reversion. Corydalis tuberosa properly lias
one of its two nectaries colourless, destitue of nectar, only half the
size of the other, and therefore, to a certain extent, in a rudimentary
state ; the pistil is curved towards the perfect nectary, and the
hood, formed of the inner petals, slips off the pistil and stamens in
one direction alone, so that, when a bee sticks the perfect nectary,
the stigma and stamens are exposed and rubbed against the in-
sect's body. In several closely allied genera, as in Dielytra, &c,
there are two perfect nectaries, the pistil is straight, and the hood

67 Verlot, ' Des Yarietes,' 1865, p. 89 ; peloric calceolarias, quoted in ' Jour-

Naudin, ' Nouvelles Archives du Muse- rial of Horticulture,' Feb. 24, 1SG3, p.

urn,' torn. 1. p. 137. 152.

e* In his discussion on some curious

78 INHERITANCE. Chap. XIII.

slips off on either side, according as the bee sucks either nectary.
Now, I have examined several flowers of Gorydalis tuberosa, in
which both nectaries were equally developed and contained nectar ;
in this we see only the redevelopment of a partially aborted organ ;
but with this redevelopment the pistil becomes straight, and the
hood slips off in either direction; so that these flowers have ac-
quired the perfect structure, so well adapted for insect agency,
of Dielytra and its allies. We cannot attribute these coadapted
modifications to chance, or to correlated variability ; we must
attribute them to reversion to a primordial condition of the species.

The peloric flowers of Pelargonium have their five petals in all
respects alike, and there is no nectary ; so that they resemble the
symmetrical flowers of the closely allied Geranium-genus ; but the
alternate stamens are also sometimes destitute of anthers, the short-
ened filaments being left as rudiments, and in this respect they re-
semble the symmetrical flowers of the closely allied genus, Erodium.
Hence we are led to look at the peloric flowers of Pelargonium as
having probably reverted to the state of some primordial form, the
progenitor of the three closely related genera of Pelargonium, Ge-
ranium, and Erodium.

In the peloric form of Antirrhinum mnjus, appropriately called
the " Wonder," the tubular and elongated flowers differ wonder-
fully from those of the common snapdragon ; the calyx and the
mouth of the corolla consist of six equal lobes, and include six equal
instead of four unequal stamens. One of the two additional stamens
is manifestly formed by the development of a microscopically min-
ute papilla, which may be found at the base of the upper lip of the
flower in all common snapdragons, at least in nineteen plants ex-
amined by me. That this papilla is a rudiment of a stamen was
well shown by its various degrees of development in crossed plants
between the common and peloric Antirrhinum. Again, a peloric
Galeobdolon luteum, growing in my garden, had five equal petals,
all striped like the ordinary lower lip, and included five equal in-
stead of four unequal stamens ; but Mr. R. Keeley, who sent me
this plant, informs me that the flowers vary greatly, having from
four to six lobes to the corolla, and from three to six stamens.09
Now, as the members of the two great families to which the
Antirrhinum and Galeobdolon belong are properly pentamerous,
with some of the parts confluent and others suppressed, we ought
not to look at the sixth stamen and the sixth lobe to the corolla in

89 For other cases of six divisions in phulariaceae, see Moquin-Tandon, ' Tera-
peloric flowers of the Labiatae and Scro- tologie,' p. 192.

Chap. XIII. REVERSION, 79

cither case as due to reversion, any more than the additional petals
in doable flowers in these same two families. But the case is dif-
ferent with the fifth stamen in the peloric Antirrhinum, which is
produced by the redevelopment of a rudiment always present, and
which prohahly reveals to us the state of the flower, as far as the
stamens are concerned, at some ancient epoch. It is also difficult
to believe that the other four stamens and the petals, after an arrest
of development at a very early embryonic age, would have come to
fall perfection in colour, structure, and function, unless these organs
had at some former period normally passed through a similar
course of growth. Hence it appears to me probable that the pro-
genitor of the genus Antirrhinum must at some remote epoch have
included five stamens and borne flowers in some degree resembling
those now produced by the peloric form.

Lastly, I may add that many instances have been recorded of
flowers, not generally ranked as peloric, in which certain organs,
normally few in number, have been abnormally augmented. As
such an increase of parts cannot be looked at as an arrest of devel-
opment, nor as due to the redevelopment of rudiments, for no rudi-
ments are present, and as these additional parts bring the plant
into closer relationship with its natural allies, they ought probably
to be viewed as reversions to a primordial condition.

These several facts show us in an interesting manner
how intimately certain abnormal states are connected
together; namely, arrests of development causing parts
to become rudimentary or to be wholly suppressed, — the
redevelopment of parts at present in a more or less rudi-
mentary condition, — the reappearance of organs of which
not a vestige can now be detected, — and to these may be
added, in the case of animals, the presence during youth,
and subsequent disappearance, of certain characters
which occasionally are retained throughout life. Some
naturalists look at all such abnormal structures as a re-
tarn to the ideal state of the group to which the affected
being belongs; but it is difficult to conceive what is
meant to be conveyed by this expression. Other natu-
ralists maintain, with greater probability and distinctness
of view, that the common bond of connection between
the several foregoing cases is an actual, though partial,

80 INHEEITANCE. Chap. XIII.

return to the structure of the ancient progenitor of the
group. If this view be correct, we must believe that a
vast number of characters, capable of evolution, lie hid-
den in every organic being. But it would be a mistake
to suppose that the number is equally great in all beings.
We know, for instance, that plants of many orders occa-
sionally become peloric ; but many more cases have been
observed in the Labiatse and Scrophulariacese than in any
other order ; and in one genus of the Scrophulariacea?,
namely Linaria, no less than thirteen species have been
described in a peloric condition.70 On this view of the
nature of peloric flowers, and bearing in mind what has
been said with respect to certain monstrosities in the ani-
mal kingdom, we must conclude that the progenitors
of most plants and animals, though widely different in
structure, have left an impression capable of redevelop-
ment on the germs of their descendants.

The fertilised germ of one of the higher animals, sub-
jected as it is to so vast a series of changes from the
germinal cell to old age, — incessantly agitated by what
Quatrefages well calls the tourbillon vital, — is perhaps
the most wonderful object in nature. It is probable that
hardly a change of any kind affects either parent, with-
out some mark being left on the germ. But on the
doctrine of reversion, as given in this chapter, the germ
becomes a far more marvellous object, for, besides the
visible changes to which it is subjected, we must believe
that it is crowded with invisible characters, proper to
both sexes, to both the right and left side of the body,
and to a long line of male and female ancestors separated
by hundreds or even thousands of generations from the
present time ; and these characters, like those written on
paper with invisible ink, all lie ready to be evolved under
certain known or unknown conditions.

70 Moquin-Tandon, ' Teratologic,' p. 186.

Chap. XIV. FIXEDNESS OF CHARACTER. 81

CHAPTER XIV.

INHERITANCE continued — FIXEDNESS OF CHARACTER —
PREPOTENCY — SEXUAL LIMITATION — CORRE-
SPONDENCE OF AGE.

FIXEDNESS OP CHARACTER APPARENTLY NOT DUE TO ANTIQUITY
OP INHERITANCE — PREPOTENCY OF TRANSMISSION UN INDIVI-
DUALS 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 — TnE IMPORTANCE OF
THE PRINCIPLE WITH RESPECT TO EMBRYOLOGY ; AS EXHIB-
ITED IN DOMESTICATED ANIMALS ; AS EXHIBITED IN THE AP-
PEARANCE AND DISAPPEARANCE OF INHERITED DISEASES ;
SOMETIMES SUPERVENING EARLIER IN TnE CHILD THAN IN THE
PARENT — SUMMARY OF TnE THREE PRECEDING CHAPTERS.

In the two last chapters the nature and force of Inheri-
tance, the circumstances which interfere with its power,
and the tendency to Reversion, with its many remarkable
contingencies, were discussed. In the present chapter
some other related phenomena will be treated of, as fully
as my materials permit.

Fixedness of Character.

It is a general belief amongst breeders that the longer
any character has been transmitted by a breed, the more
firmly it will continue to be transmitted. I do not^vish

82 INHERITANCE. Chap. XIV.

to dispute the truth of the proposition, that inheritance
gains strength simply through long continuance, but I
doubt whether it can be proved. In one sense the pro-
position is little better than a truism ; if any character
has remained constant during many generations, it will
obviously be little likely, the conditions of life remaining
the same, to vary during the next generation. So, again,
in improving a breed, if care be taken for a length of
time to exclude all inferior individuals, the breed will
obviously tend to become truer, as it will not have been
crossed during many generations by an inferior animal.
We have previously seen, but without being able to
assign any cause, that, when a new character appears, it
is occasionally from the first well fixed, or fluctuates
much, or wholly fails to be transmitted. So it is with
the aggregate of slight differences which characterise a
new variety, for some propagate their kind from the first
much truer than others. Even with plants multiplied
by bulbs, layers, <fcc, which may in one sense be said to
form parts of the same individual, it is well known that
certain varieties retain and transmit through successive
bud-generations their newly-acquired characters more
truly than others. In none of these, nor in the following '
cases, does there appear to be any relation between the
force with which a character is transmissible and the
length of time during which it has already been trans-
mitted. Some varieties, such as white and yellow hya-
cinths and white sweet-peas, transmit their colours more
faithfully than do the varieties which have retained
their natural colour. In the Irish family, mentioned in
the twelfth chapter, the peculiar tortoiseshell-like colour-
ing of the eyes was transmitted far more faithfully than
any ordinary colour. Ancon and Mauchamp sheep and
niata cattle, which are all comparatively modern breeds,
exhibit' remarkably strong powers of inheritance. Many
similar cases could be adduced.

A^all domesticated animals and cultivated plants have

Chap. XIV. PBEPOTENCY OF TRANSMISSION. 83

varied, and yet are descended from aboriginally wild
forms, which no doubt had retained the same character
from an immensely remote epoch, we see that scarcely
any degree of antiquity ensures a character being trans-
mitted perfectly true. In this case, however, it may be
said that changed conditions of life induce certain modi-
fications, and not that the power of inheritance fails ; but
in every case of failure, some cause, either internal or
external, must interfere. It will generally be found that
the parts in our domesticated productions which have
varied, or which still continue to vary, — that is, which
foil to retain their primordial state, — are the same with
the parts which differ in the natural species of the same
genus. As, on the theory of descent with modification,
the species of the same genus have been modified since
they branched off from a common progenitor, it follows
that the characters by which they differ from each other
have varied whilst other parts of the organisation have
j'emained unchanged ; and it might be argued that these
same characters now vary under domestication, or fail
to be inherited, owing to their lesser antiquity. But
we must believe structures, which have already varied,
would be more liable to go on varying, rather than struc-
tures which during an immense lapse of time have re-
mained unaltered^ and this variation is probably the
result of certain relations between the conditions of life
and the organisation, quite independently of the greater
or less antiquity of each particular character.

Fixedness of character, or the strength of inheritance,
has often been judged of by the preponderance of certain
characters in the crossed offspring between distinct races ;
but prepotency of transmission here comes into play,
and this, as we shall immediately see, is a very different
consideration from the strength or weakness of inheri-
tance. It has often been observed ' that breeds of ani-

1 See Youatt on Cattle, pp. 92, 69, 78, Also Dr. Lucas, ' L'H^red. Nat.,' torn-
3, 163 : also Touatt on Sheep, p. 325. 11. p. 810.

84 INHERITANCE. Chap. XIV.

mals inhabiting wild and mountainous countries can-
not be permanently modified by our improved breeds ; and
as these latter are of modern origin, it has been thought
that the greater antiquity of the wilder breeds has been
the cause of their resistance to improvement by crossing ;
but it is more probably due to their structure and consti-
tution being better adapted to the surrounding conditions.
When plants are first subjected to culture, it has been
found that, during several generations, they transmit
their characters truly, that is, do not vary, and this has
been attributed to ancient characters being strongly
inherited ; but it may with equal or greater probability
be consequent on changed conditions of life requiring
a long time for their accumulative action. Notwith-
standing these considerations, it Avould perhaps be rash
to deny that characters become more strongly fixed the
longer they are transmitted ; but I believe that the pro-
position resolves itself into this, — that all characters of
all kinds, whether new or old, tend to be inherited, and
that those which have already withstood all counteract-
ing influences and been truly transmitted, will, as a gen-
eral rule, continue to withstand them, and consequently
be faithfully inherited.

Prepotency in the Transmission of Character.
"When individuals distinct enough to be recognised, but
of the same family, or when two well-marked races, or
two species, are crossed, the usual result, as stated in the
previous chapter, is, that the ofFsp ring in the first genera-
tion are intermediate between their parents, or resemble
one parent in one part and the other parent in another
part. But this is by no means the invariable rule ; for in
many cases it is found that certain individuals, races, and
species are prepotent in transmitting their likeness. This
subject has been ably discussed by Prosper Lucas,8 but

s 'Hered. Nat.,' torn. ii. pp. 112-120.

Chap. XIV. PKEPOTENCY OF TRANSMISSION. 85

is rendered extremely complicated by the prepotency
sometimes running equally in both sexes, and sometimes
more strongly in one sex than in the other; it is likewise
complicated by the presence of secondary sexual charac-
ters, which render the comparison of mongrels with their
parent-breeds difficult.

It would appear that in certain families some one an-
cestor, and after him others in the same family, must
have had great power in transmitting their likeness
through the male line ; for we cannot otherwise under-
stand how the same features should so often be trans-
mitted after marriages with various females, as has been
the case with the Austrian Emperors, and as, according to
Niebuhr, formerly occurred in certain Roman families
with their mental qualities.3 The famous bull Favourite
is believed4 to have had a prepotent influence on the
shorthorn race. It has also been observed 5 with English
race-horses that certain mares have generally transmitted
their own character, whilst other mares of equally pure
blood have allowed the character of the sire to prevail.

The truth of the principle of prepotency comes out more clearly
when certain races are crossed. The improved Shorthorns, notwith-
standing that the breed is comparatively modern, are generally ac-
knowledged to possess great power in impressing their likeness on
all other breeds ; and it is chiefly in consequence of this power that
they are so highly valued for exportation.6 Godine has given a
curious case of a ram of a goat-like breed of sheep from the Cape
of Good Hope, wThich produced offspring hardly to be distinguished
from himself, when crossed with ewes of twelve other breeds. But
two of these half-bred ewes, when put to a merino ram, produced
lambs closely resembling the merino breed. Girou de Buzarein-
gues 7 found that of two races of French sheep the ewes of one, when

' Sir n. nolland, 'Chapters on Mental Natur,' b. ii. s. 170. See Sturm, 'Ueber

Physiology,' 1853, p. '234. Racen,' ls25, 6. 104-107. For the niata

* 'Gardener's Chronicle,' I860, p. 270. cattle, see my ' Journal of Researches,'

5 Mr. N. II. Smith, Observations on 1845, p. 146.

Breeding, quoted in ' Encyclop. of Rural 7 Lucas, ' L'Heredite Nat.,' torn. ii. p.

Sports,' p. 273. , 112.

6 Quoted by Bronn, ' Geschichte der

86 INHERITANCE. Our. XIV.

crossed during successive generations with merino rams, yielded up
their character far sooner than the ewes of the other race. Sturm
and Girou have given analogous cases with other breeds of sheep
and with cattle, the prepotency running in these cases through the
male side ; but I was assured on good authority in Soutli America,
that when niata cattle are crossed with common cattle, though the
niata breed is prepotent whether males or females are used, yet that
the prepotency is strongest through the female line. The Manx
cat is tailless and has long hind legs ; Dr. Wilson crossed a male
Manx with common cats, and, out of twenty-three kittens, seven-
teen were destitute of tails ; but when the female Manx was crossed
. by common male cats all the kittens had tails, though they were
generally short and imperfect."

In making reciprocal crosses between pouter and fantail pigeons,
the pouter-race seemed to be prepotent through both sexes over the
fantail. But this is probably due to weak power in the fantail
rather than to any unusually strong power in the pouter, for I have
observed that barbs also preponderated over fantails. This weak-
ness of transmission in the fantails, though the breed is an ancient
one, is said9 to be general ; but I have observed one exception to
the rule, namely, in a cross between a fantail and laugher. The
most curious instance known to me of weak power in both sexes is
in the trumpeter pigeon. This breed has been well known for at
least 130 years : it breeds perfectly true, as I have been assured by
those who have long kept many birds : it is characterised by a pe-
culiar tuft of feathers over the beak, by a crest on the head, by a
most peculiar coo quite unlike that of any other breed, and by much-
feathered feet. I have crossed both sexes with turbits of two sub-
breeds, with almond tumblers, spots, and runts, and reared many
mongrels and recrossed them ; and though the crest on the head
and feathered feet were inherited (as is generally the case with most
breeds), I have never seen a vestige of the tuft over the beak or
heard the peculiar coo. Boitard and Corbie 10 assert that this is the
invariable result of crossing trumpeters with any other breed : Neu-
meister,11 however, states that in Germany mongrels have been ob-
tained, though very rarely, which were furnished with the tuft and
would trumpet : but a pair of these mongrels with a tuft, which I
imported, never trumpeted. Mr. Brent states 12 that the crossed
offspring of a trumpeter were crossed with trumpeters for three

8 Mr. Orton, ' Physiology of Breeding,' 10 ' Les Pigeons,' pp. 168, 198.
1855, p. 9. » ' Das Ganze,' Ac, 1837, s. 39.

9 Boitard and Corbie, 'Les Pigeons,' ia ' The Pigeon Book,' p. 46.
1824, p. '224.

Chap. XIV. PREPOTENCY OF TRANSMISSION. 87

generations, by which time mongrels had 7-8ths of this blood in
their veins, yet the tuft over the beak did not appear. At the fourth
generation the tuft appeared, but the birds, though now having 15-
lGths trumpeter's blood, still did not trumpet. This ease well shows
the wide difference between inheritance and prepotency ; for here
we have a well-established old race which transmits its characters
faithfully, but which, when crossed with any other race, has the
feeblest power of transmitting its two chief characteristic qualities.

I will give one other instance with fowls and pigeons of weakness
and strength in the transmission of the same character to their cross-
ed offspring. The Silk-fowl breeds true, and there is reason to believe
is a very ancient race ; but when I reared a large number of mon-
grels from a Silk-hen by a Spanish cock, not one exhibited even a
trace of the so-called silkiness. Mr. Hewitt also asserts that in do
instance are the silky feathers transmitted by this breed when
crossed with any other variety. But three birds out of many raised
by Mr. Orton from a cross between a silk-cock and a bantam-hen,
had silky feathers.13 So that it is certain that this breed very sel-
dom has the power of transmitting its peculiar plumage to its .
crossed progeny. On the other hand, there is a silk sub-variety of
the fantail pigeon, which has its feathers in nearly the same state
as in the Silk-fowl : now we have already seen that fantails, when
crossed, possess singularly weak power in transmitting their gene-
ral qualities ; but the silk sub-variety when crossed with any other
small-sized race invariably transmits its silky feathers ! "

The law of prepotency comes into action when species are crossed,
as with races and individuals. Gartner has unequivocally shown lb
that this is the case with plants. To give one instance : when _ZV&-
cot inn a panic ulata and vincmflora are crossed, the character of JV.
paniculata is almost completely lost in the hybrid ; but if iV. qua-
drivalvis be crossed with JV. mncceflora, this latter species, which
was before so prepotent, now in its turn almost disappears under the
power of 2V. quadrivalvis. It is remarkable that the prepotency of
one species over another in transmission is quite independent, as
shown by Gartner, of the greater or less facility with which the one
fertilises the other.

With animals, the jackal is prepotent over the dog, as is stated by

13 'Physiology of Breeding,' p. 22; Ac. Naudin ('Nouvelles Archives du

Mr. Hewitt, in 'The Poultry Book,' by Museum,' torn. i. p. 149) gives a striking

Tegetraeier, 1S66, p. 224. instance of prepotency in Datura stra-

11 Boitard and Corbie, 'Les Pigeons,' mo>nu?n when crossed with two other

1824, p. 226. species.

15 ' Ba6tarUerzeugang,' s. 250, 290,

88 INHERITANCE. Chap. XIV.

Flourens, who made many crosses between these animals ; and this
was likewise the case with a hybrid which I once saw between a
jackal and terrier. I cannot doubt, from the observations of Colin
and others, that the ass is prepotent over the horse ; the prepotency
in this instance running more strongly through the male than
through the female ass ; so that the mule resembles the ass more
closely than does the hinny.16 The male pheasant, judging from
Mr. Hewitt's descriptions,17 and from the hybrids which I have seen,
preponderates over the domestic fowl ; but the latter, as far as colour
is concerned, has considerable power of transmission, for hybrids
raised from five differently coloured hens differed greatly in plu-
mage. I formerly examined spme curious hybrids in the Zoological
Gardens, between the Penguin variety of the common duck and the
Egyptian goose ( Tadorna JEgyptiacd) ; and although I will not as-
sert that the domesticated variety preponderated over the natural
species, yet it had strongly impressed its unnatural upright figure
on these hybrids.

I am aware that such cases as the foregoing have been ascribed
by various authors, not to one species, race, or individual being pre-
potent over the other in impressing its character on its crossed off-
spring, but to such rules as that the father influences the external
characters and the mother the internal or vital organs. But the
great diversity of the rules given by various authors almost proves
their falseness. Dr. Prosper Lucas has fully discussed this point,
and has shown 1B that none of the rules (and i. could add others to

in Flourens, ' Longevite ITumaine,' p. hybrid which I saw in the Zoological

144, on crossed jackals. With respect to Gardens, from a mare by a hybrid ass-

the difference between the mule and the zebra, closely resembled its mother in

hinny, I am aware that this has general- its tail.

ly been attributed to the sire and dam 17 Mr. Hewitt, who has had such
transmitting their characters differently; great experience in raising these hy-
but Colin, who has given in his ' Traite brids, says (' Poultry Book,' by Mr. Te-
Phys. Comp.,' torn. ii. pp. 537-539, the getmeier, 1S66, pp. 165-167) that in all,
fullest description which I have met the head was destitute of wattles, comb,
with of these reciprocal hybrids, is and ear-lappets ; and all closely resem-
strongly of opinion that the ass prepon- bled the pheasant in the shape of the tail
derates in both crosses, but in an unequal and general contour of the body. These
degree. This is likewise the conclusion hybrids were raised from hens of several
of Flourens, and of Bechstein in his breeds by a cock-pheasant ; but another
' Naturgeschichte Deutschlands,' b. i. hybrid, described by Mr. Hewitt, was
g. 294. The tail of the hinny is much raised from a hen-pheasant by a silver-
more like that of the horse than is the laced Bantam cock, and this possessed a
tail of the mule, and this is generally ac- rudimental comb and wattles,
counted for by the males of both species 18 ' L'Hered. Nat.,' torn. ii. book ii.
transmitting with greater power this ch. i.
part of their structure ; but a compound

Chap. XIV. PREPOTENCY/ OF TRANSMISSION. 89

those quoted by him) apply to all animals. Similar rules have been
enounced for plants, and have been proved by Gartner 18 to be all
erroneous. If we confine our view to the domesticated races of a
single species, or perhaps even to the species of the same genus",
some such rules may hold good ; for instance, it seems that in reci-
procally crossing various breeds of fowls the male geuerally gives
colour ; 20 but conspicuous exceptions have passed under my own
eyes. In sheep it seems that the ram usually gives its peculiar
horns and fleece to its crossed offspring, and the bull the presence
or absence of horns.

In the following chapter on Crossing I shall have occasion to show
that certain characters are rarely or never blended by crossing, but
are transmitted in an unmodified state from either parent-form ; I
refer to this fact here because it is sometimes accompanied on the
one side by prepotency, which thus acquires the false appearance of
unusual strength. In the same chapter I shall show that the rate
at which a species or breed absorbs and obliterates another by re-
peated crosses, depends in chief part on prepotency in transmission.

In conclusion, some of the cases above given, — for in-
stance, that of the trumpeter pigeon, — prove that there
is a wide difference between mere inheritance and pre-
potency. This latter power seems to us, in our ignorance,
to act in most cases quite capriciously. The very same
character, even though it be an abnormal or monstrous
one, such as silky feathers, may be transmitted by differ-
ent species, when crossed, either with prepotent force or
singular feebleness. It is obvious, that a purely-bred
form of either sex, in all cases in which prepotency does
not run more strongly in one sex than the other, will
transmit its character with prepotent force over a mon-
grelized and already variable form.21 From several of
the above-given cases we may conclude that mere anti-
quity of character does not by any means necessarily
make it prepotent. In some cases prepotency apparently

19 ' Bastarderzeugung,' 8. 264-2"6. 137.

Naudin ('Nouvelles Archives du Muse- 21 See some remarks on this head with

urn,' torn. i. p. 14S) has arrived at a si- respect to sheep by Mr. Wilson, in ' Gar*

milar conclusion. dener's Chronicle,' 1863, p. 15.

s» ' Cottage Gardener,' 1S56, pp. 101,

90 INHERITANCE. Chap. XIV.

depends on the same character being present and visible
in one of the two breeds which are crossed, and latent or
invisible in the other breed ; and in this case it is natural
that the character which is potentially present in both
should be prepotent. Thus, Ave have reason to believe
that there is a latent tendency in all horses to be dun-
coloured and striped ; and when a horse of this kind is
crossed with one of any other colour, it is said that the
offspring are almost sure to be striped. Sheep have a
similar latent tendency to become dark-coloured, and Ave
have seen Avith what prepotent force a ram Avith a few black
spots, Avhen crossed with Avhite sheep of various breeds,
coloured its offspring. All pigeons have a latent ten-
dency to become slaty-blue, Avith certain characteristic
marks, and it is known that, when a bird thus coloured
is crossed with one of any other colour, it is most difficult
afterwards to eradicate the blue tint. A nearly parallel
case is offered by those black bantams Avhich, as they
grow old, develop a latent tendency to acquire red feath-
ers. But there are exceptions to the rule: hornless breeds
of cattle possess a latent capacity to reproduce horns, yet
Avhen crossed with horned breeds they do not invariably
produce offspring bearing horns.

We meet with analogous cases with plants. Striped
flowers, though they can be propagated truly by seed,
have a latent tendency to become uniformly coloured,
but Avhen once crossed by a uniformly coloured variety,
they ever afterwards fail to produce striped seedlings.'"2
Another case is in some respects more curious: plants
bearing peloric or regular flowers haAre so strong a latent
tendency to reproduce their normally irregular flowers,
that this often occurs by buds Avhen a plant is transplanted
into poorer or richer soil.23 Now I crossed the peloric
snapdragon {Antirrhinum majus), described in the last

22 Verlot, « Des Varietes,' 1SG5, p. 66.

23 Moquin-Tandon, ' Teratologic,' p. 191.

"Chap. xiy. PREPOTENCY OF TRANSMISSION. 91

chapter, with pollen of the common form; and the latter,
reciprocally, with pelorie pollen. I thus raised two great
beds of seedlings, and not one was pelorie. Naudin24
obtained the same result from crossing a pelorie Linaria
with the common form. I carefully examined the flowers
of ninety plants of the crossed Antirrhinum in the two
beds, and their structure had not been in the least affected
by the cross, except that in a few instances the minute
rudiment of the fifth stamen, which is always pi*esent,
was more fully or even completely developed. It must
not be supposed that this entire obliteration of the pelorie
structure in the crossed plants can be accounted for by
any incapacity of transmission ; for I raised a large bed
of plants from the pelorie Antirrhinum, artificially fertil-
ised by its own pollen, and sixteen plants, which alone
survived the winter, were all as perfectly pelorie as the
parent plant. Here we have a good instance of the wide
difference between the inheritance of a character and the
power of transmitting it to crossed offspring. The crossed
plants, which perfectly resembled the common snapdra-
gon, were allowed to sow themselves, and out of a hundred
and twenty-seven seedlings, eighty-eight proved to be
common snapdragons, two were in an intermediate con-
dition between the pelorie and normal state, and thirty-
seven were perfectly pelorie, having reverted to the
structure of their one grandparent. This case seems at
first sight to offer an exception to the rule formerly
given, namely, that a character which is present in one
form and latent in the other is generally transmitted with
prepotent force wThen the two forms are crossed. For in
all the Scrophulariaceae, and especially in the genera
Antirrhinum and Linaria, there is, as was shown in tho
last chapter, a strong latent tendency to become pelorie ;
and there is also, as we have just seen, a still stronger
tendency in all pelorie plants to reacquire their normal

34 ' Nouvelles Archives du Museum,' torn. i. p. 137.

92 INHERITANCE. Chap. XIV. •

irregular structure. So that we have two opposed latent
tendencies in the same plants. Now, with the crossed
Antirrhinums the tendency to produce normal or irregular
flowers, like those of the common Snapdragon, prevailed
in the first generation ; whilst the tendency to pelorism,
appearing to gain strength by the intermission of a gene-
ration, prevailed to a large extent in the second set of
seedlings. How it is possible for a character to gain
strength by the intermission of a generation, will be con-
sidered in the chapter on pangenesis.

On the whole, the subject of prepotency is extremely
intricate, — from its varying so much in strength, even in
regai'd to the same character, in different animals, — from
its running either equally in both sexes, or, as frequently
is the case with animals, but not with plants, much
stronger in the one sex than the other, — from the ex-
istence of secondary sexual characters, — from the trans-
mission of certain characters being limited, as we shall
immediately see, by sex, — from certain characters not
blending together, — and, perhaps, occasionally from the
eflects of a previous fertilisation on the mother. It is
therefore not surprising that every one hitherto has been
baffled in drawing up general rules on the subject of pre-
potency.

' Inheritance as limited by Sex.

New characters often appear in one sex, and are after-
wards transmitted to the same sex, either exclusively or
in a much greater degree than to the other. This sub-
ject is important, because with animals of many kinds
in a state of nature, both high and low in the scale, sec-
ondary sexual characters, not in any way directly con-
nected with the organs of reproduction, are often con-
spicuously present. With our domesticated animals, also,
these same secondary characters are often found to differ
greatly from the state in which they exist in the parent-
species. And the principle of inheritance as limited by

Chap. XIV. SEXUAL LIMITATION. 93

sex shows how such characters might have been first ac-
quired and subsequently modified.

Dr. P. Lucas, who lias collected many facts on this subject,
shows"5 that when a peculiarity, in no manner connected with the
reproductive organs, appears in either parent, it is often transmitted
exclusively to the offspring of the same sex, or to a much greater
number of them than of the opposite sex. . Thus, in the family of
Lambert, the horn-like projections on the skin were transmitted
from the father to his sons and grandsons alone ; so it has been
with other cases of ichthyosis, with supernumerary digits, with a
deficiency of digits and phalanges, and in a lesser degree with va-
rious diseases, especially with coloirr-blindness, and a hemorrhagic
diathesis, that is, an extreme liability to profuse and uncontrollable
bleeding from trifling wounds. On the other hand, mothers have
transmitted, during several generations, to their daughters alone,
supernumerary and deficient digits, colour-blindness, and other pe-
culiarities. So that we see that the very same peculiarity may be-
come attached to either.sex, and be long inherited by that sex alone ;
but the attachment in certain cases is much more frequent to one
than the other sex. The same peculiarities also may be promiscu-
ously transmitted to either sex. Dr. Lucas gives other cases, allow-
ing that the male occasionally transmits his peculiarities to his
daughters alone, and the mother to her sons alone ; but even in this
case we see that inheritance is to a certain extent, though inversely,
regulated by sex. Dr. Lucas, after Aveighing the whole evidence,
comes to the conclusion that every peculiarity, according to the
sex in which it first appears, tends to be transmitted in a greater or
lesser degree to that sex.

A few details from the many cases collected by Mr. Sedgwick,26
may be here given. Colour-blindness, from some unknown cause,
shows itself much oftener in males than in females ; in upwards
of two hundred cases collected by Mr. Sedgwick, nine-tenths related
to men ; but it is eminently liable to be transmitted through wo-
men. In the case given by Dr. Earle, members of eight related
families were affected during five generations : these families con-
sisted of sixty-one individuals, namely, of thirty-two males, of whom
nine-sixteenths were incapable of distinguishing colour, and of twen-
ty-nine females, of whom only one-fifteenth were thus affected. Al-

55 'L'IIer6d. Nat.,' torn, ii., pp.137- Diseases, ' Brit, and For. Med.-CIiirurg.

165. See, also, Mr. Sedgwick's four me- Review,' April, 1S01, p. 477; July, p.

moirs, immediately to be referred to. 19S; April, 1S03, p. 445; and July, p.

88 On Sexual Limitation in Hereditary 159.

94 INHERITANCE. Chap. XIV.

though colour-blindness thus generally clings to the male sex, nev-
ertheless, in one instance in which it first appeared in a female, it
was transmitted during five generations to thirteen individuals, all
of whom were females. A hsemorrhagic diathesis, often accompa-
nied by rheumatism, has been known to affect the males alone dur-
ing five generations, being transmitted, however, through the
females. It is said that deficient phalanges in the fingers have been
inherited by the females alone during ten generations. In another
case, a man thus deficient in both lrands and feet, transmitted the
peculiarity to his two sons and one daughter ; but in the third gen-
eration, out of nineteen grandchildren, twelve sons had the family
defect, whilst the seven daughters were free. In ordinary cases of
sexual limitation, the sons or daughters inherit the peculiarity,
whatever it may be, from their father or mother, and transmit it
to their children of the same sex ; but generally with the hemor-
rhagic diathesis, and often with colour-blindness, and in some other
cases, the sons never inherit the peculiarity directly from their
fathers, but the daughters, and the daughters alone, transmit the
latent tendency, so that the sons of the daughters alone exhibit it.
Thus, the father, grandson, and great-great-grandson will exhibit a
peculiarity, — the grandmother, daughter, and great-granddaughter
having transmitted it in a latent state. Hence we have, as Mr.
Sedgwick remarks, a double kind of atavism or reversion ; each
grandson apparently receiving and developing the peculiarity from
his grandfather, and each daughter apparently receiving the latent
tendency from her grandmother.

From the various facts recorded by Dr. Prosper Lucas, Mr. Sedg-
wick, and others, there can be no doubt that peculiarities first
appearing in either sex, though not in any way necessarily or inva-
riably connected with that sex, strongly tend to be inherited by the
offspring of the same sex, but are often transmitted in a latent
state through the opposite sex.

Turning now to domesticated animals, we find that certain charac-
ters not proper to the parent-species, are often confined to, and in-
herited by, one sex alone ; but we do not know the history of the
first appearance of such characters. In the chapter on Sheep, we
have seen that the males of certain races differ greatly from the
females in the shape of their horns, these being absent in the ewes
of some breeds, in the development of fat in the tail in certain fat-
tailed breeds, and in the outline of the forehead. These differences,
judging from the character of the allied wild species, cannot be ac-
counted for by supposing that they have been derived from distinct
parent-forms. There is, also, a great difference between the horns of
the two sexes in one Indian breed of goats. The bull zebu is said to

Chap. XIV. SEXUAL LIMITATION. 95

have a larger hump than the cow. In the Scotch deer-hound the two
pcxcs differ in size more than in any other variety of the dog,'-'1 and,
judging from analogy, more than in the aboriginal parent-species.
The peculiar colour called tortoise-shell is very rarely seen in a
male cat ; the males of this variety being of a rusty tint. A ten-
dency to baldness in man before the advent of old age is certainly
inherited ; and. in the European, or at least in the Englishman, is an
attribute of the male sex, and may almost be ranked as an incipient
secondary sexual character.

In various breeds of the fowl the males and females often differ
greatly ; and these differences are far from being the same with
those which distinguish the two sexes in the parent-species, the
Gattus In ultra ; and consequently have originated under domesti-
cation. In certain sub-varieties of the Game race we have the un
usual case of the hens differing from each other more than the cocks.
In an Indian breed of a white colour stained with soot, the hens
invariably have black skins, and their bones are covered by a
black periosteum, whilst the cocks are never or most rarely thus
characterised. Pigeons offer a more interesting case ; for the twc
sexes rarely differ throughout the whole great family, and the males
and females of the parent form, the C. litia, are undistinguishable ;
yet we have seen that with Pouters the male has the characteristic
quality of pouting more strongly developedlhan the female ; and
in certain sub-varieties 28 the males alone are spotted or striated with
black. When male and female English carrier-pigeons are exhi-
bited in separate pens, the difference in the development of the wat-
tle over the beak and round the eyes is conspicuous. So that here
we have instances of the appearance of secondary sexual characters
in the domesticated races of a species in which such differences are
naturally quite absent. #

On the other hand, secondary sexual characters which
properly belong to the species are sometimes quite lost,
or greatly diminished, under domestication. We see this
in the small size of the tusks in our improved breeds of the
pig, in comparison with those of the wild boar. There
are sub-breeds of fowls in which the males have lost the
fine flowing tail-feathers and hackles ; and others in Avhich

27 W. Scrope, ' Art of Deer Stalking,' p. p. 1T3; Dr. P. Chapuis, ' Le Pigeon
854. Voyageur Beige,' 1S65, p. ST.

2S Boitard and Corbie, ' I.es Pigeons,'

96 INHEEITANCE Chap. XIV.

there is no difference in colour between the two sexes.
In some cases the barred plumage, which in gallinaceous
birds is commonly the attribute of the hen, has" been
transferred to the cock, as in the cuckoo sub-breeds. In
other cases masculine characters have been partly trans-
ferred to the female, as with the splendid plumage of the
golden-spangled Hamburgh hen, the enlarged comb of
the Spanish hen, the pugnacious disposition of the Game
hen, and as in the well-developed spurs which occasion-
ally appear in the hens of various breeds. In Polish
fowls both sexes are ornamented with a topknot, that of
the male being formed of hackle-like feathers, and this
is a new male character in the genus Gallus. On the
whole, as far as I can judge, new characters are more apt
to appear in the males of our domesticated animals than
in the females, and afterwards to be either exclusively or
more strongly inherited by the males. Finally, in accord-
ance with the principle of inheritance as limited by sex,
the appearance of secondary sexual characters in natural
species offers no especial difficulty, and their subsequent
increase and modification, if of any service to the species,
would follow through that form of selection which in
my ' Origin of Species' I have called sexual selection.

Inheritance at corresponding periods of Life.

This is an important subject. Since the publication of
my ' Origin of Species,' I have seen no reason to doubt
the truth of the explanation there given of perhaps the
most remarkable of all the facts in biology, namely, the
difference between the embryo and the adult animal. The
explanation is, that variations do not necessarily or gen-
erally occur at a very early period of embryonic growth,
and that such variations are inherited at a corresponding
age. As a consequence of this the embryo, even when
the parent-form undergoes a great amount of modifica-
tion, is left only slightly modified ; and the embryos of

Chap. XIV. AT CORRESPONDING PERIODS. 97

widely-different animals which are descended from a
common progenitor remain in many important respects
like each other and their common progenitor. We can
thus understand why embryology should throw a flood
of light on the natural system of classification, for this
ought to be as far as possible genealogical. When the
embryo leads an independent life, that is, becomes a
larva, it has to be adapted to the surrounding condi-
tions in its structure and instincts, independently of
those of its parents ; and the principle of inheritance
at corresponding periods of life renders this possible.

This principle is, indeed, in one way so obvious that it
escapes attention. We possess a number of races of ani-
mals and plants, which, when compared with each other
and with their parent-forms, present conspicuous differ-
ences, both in the immature and mature states. Look at
the seeds of the several kinds of peas, beans, maize, which
can be propagated truly, and see how they differ in size,
colour, and shape, whilst the full-grown plants differ but
little. Cabbages on the other hand differ greatly in fo-
liage and manner of growth, but hardly at all in their
"seeds; and generally it will be found that the differ-
ences between cultivated plants at different periods of
growth are not necessarily closely connected together,
for plants may differ much in their seeds and little when
full-grown, and conversely may yield seeds hardly dis-
tinguishable, yet differ much when full-grown. In the
several breeds of poultry, descended from a single spe-
cies, differences in the eggs and chickens, in the plu-
mage at the first and subsequent moults, in the comb
and wattles during maturity, are all inherited. With
man peculiarities in the milk and second teeth, of which
I have received the details, are inheritable, and with man
longevity is often transmitted. So again with our im-
proved breeds of cattle and sheep, early maturity, in-
cluding the early development of the teeth, and with
certain breeds of fowl the early appearance of secon-

98 INHERITANCE Chap. XIV

dary sexual characters, all come under the same head
of inheritance at corresponding periods.

Numerous analogous facts could he sjiven. The silk-
moth, perhaps, offers the best instance; for in the breeds
which transmit their characters truly, the eggs differ in
size, colour, and shape ; — the caterpillars differ, in moult-
ing three or four times, in colour, even in having a dark-
coloured mark like an eyebrow, and in the loss of certain
instincts ; — the cocoons differ in size, shape, and in the
colour and quality of the silk ; these several differences
being followed by slight or barely distinguishable differ-
ences in the mature moth.

But it may be said that, if in the above cases a new
peculiarity is inherited, it must be at the corresponding
stage of development ; for an egg or seed can resemble
only an egg or seed, and the horn in a full-grown ox can
resemble only a horn. The following cases show inheri-
tance at corresponding periods more plainly, because they
refer to peculiarities which might have supervened, as far
as we can see, earlier or later in life, yet are inherited at-
the same period at which they first appeared.

In the Lambert family the porcupine-like excrescences appeared in
the father and sons at the same age, namely, about nine weeks after
birth.29 In the extraordinary hairy family described by Mr. Craw-
furd,30 children were produced during three generations with hairy
ears ; in the father the hair began to grow over his body at six years
old ; in his daughter somewhat earjier, namely, at one year ; and in
both generations the milk teeth appeared late in life, the perma-
nent teeth being afterwards singularly deficient. Greyness of hair
at an unusually early age has been transmitted in some families.
These cases border on diseases inherited at corresponding periods
of life, to which I shall immediately refer.

It is a well-known peculiarity with almond-tumbler pigeons, that
the full beauty and peculiar character of the plumage does not ap-

29 Pricliard, ' Phys. Hist, of Mankind,' scribed by Capt. Yule in his * Narrative
1S51, vol. i. p. 349, of the Mission to the Court of Ava,'

30 ' Embassy to the Court of Ava,' vol. 185o, p. 94.
1. p. 320. The third generation is de-

Chap. XIV. AT CORRESPONDING PERIODS. 99

pear until the bird has moulted two or three times. Neumeister
describes and figures a breed of pigeons in which the whole body
is white except the breast, neck, and head ; but before the first
moult all the white feathers acquire coloured edges. Another breed
is more remarkable : its first plumage is black, with rusty-red wing-
bars and a crescent-shaped mark on the breast ; these marks then
become white, and remain so during three or four moults ; but
after this period the white spreads over the body, and the bird loses
its beauty.31 Prize canary-birds have their wings and tail black :
" this colour, however, is only retained until the first moult, so that.
" they must be exhibited ere the change takes place. Once moulted,
" the peculiarity has ceased. Of course all the birds emanating from
" this stock have black wings and tails the first year." 32 A curious
and somewhat analogous account has been given33 of a family
of wild pied rooks which were first observed in 1798, near Chal-
font, and which every year from that date up to the period of the
published notice, viz. 1837, " have several of their brood parti-
" coloured, black and white. This variegation of the plumage,
" however, disappears with the first moult ; but among the next
" young families there are always a few pied ones." These changes
of plumage, which appear and are inherited at various correspond-
ing periods of life in the pigeon, canary-bird, and rook, are remark-
able, because the parent-species undergo no such change.

Inherited diseases afford evidence in some respects of less value
than the foregoing cases, because diseases are not necessarily con-
nected with any change in structure ; but in other respects of more
value, because the periods have been more carefully observed. Cer-
tain diseases are communicated to the child apparently by a process
like inoculation, and the child is from the first affected ; such cases
may be here passed over. Large classes of diseases usually appear
at certain ages, such as St. VitusWlance in youth, consumption in
early mid-life, gout later, and apoplexy still later ; and these are
naturally inherited at the same period. But even in diseases of this
class, instances have been recorded, as with St. Vitus's dance, show-
ing that an unusually early or late tendency to the disease is inherit-
able.34 In most caseS the appearance of any inherited disease is
largely determined by certain critical periods in each person's life,
as well as by unfavourable conditions. There are many other dis-
eases, which are not attached to any particular period, but which

si 'Das GanzederTaubenzucht,'lS37, 33 Cbarlesworth, ' Mag. of Nat. Hist.'

g. 21, tab. i., fig. 4 ; s. 24, tab. iv., fig. 2. vol. i., 18-57, p. 107.

33 Kidd's ' Treatise oq the Canary,' j). 3i Dr. Prosper Lucas, ' Hered. Nat.,'

18. torn, ii., p. 713.

100 INHERITANCE Chap. XIV.

certainly tend to appear in the child at about the same age at which
the parent was first attacked. An array of high authorities, ancient
and modern, could be given in support of this proposition. The
illustrious Hunter believed in it ; and Piorry *5 cautions the physician
to look closely to the child at the period when any grave inherit-
able disease attacked the parent. Dr. Prosper Lucas,36 after collect-
ing facts from every source, asserts that affections of all kinds,
though not related to any particular period of life, tend to reappear
in the offspring at whatever period of life they first appeared in the
progenitor.

As the subject is important, it may be well to give a few in-
stances, simply as illustrations, not as proof; for proof, recourse
must be had to the authorities above quoted. Some of the follow-
ing cases have been selected for the sake of showing that, when a
slight departure from the rule occurs, the child is affected somewhat
earlier in life than the parent. In the family of Le Compte blind-
ness was inherited during three generations, and no less than thirty-
seven children and grandchildren were all affected at about the
same age, namely seventeen or eighteen.37 In another case a father
and his four children all became blind at twenty-one years old ; in
another, a grandmother grew blind at thirty-five, her daughter at
nineteen, and three grandchildren at the ages of thirteen and
eleven.38 So with deafness, two brothers, their father and paternal
grandfather, all became deaf at the age of forty.39

Esquirol gives several striking instances of insanity coming on at
the same age, as that of a grandfather, father, and son, who all
committed suicide near their fiftieth year. Many other cases could
be given, as of a whole family who became insane at the age of
forty.40 Other cerebral affections sometimes follow the same rule, —
for instance, epilepsy and apoplexy. A woman died of the latter
disease when sixty-three years^ld ; one of her daughters at forty-
three, and the other at sixty-seven : the latter had twelve children,
who all died from tubercular meningitis.41 I mention this latter
case because it illustrates a frequent occurrence, namely, a change

35 ' LTTered. dans les Maladies,' 1840, differ in the details ! but as they agree in
p. 135. For Hunter, see Harlan's ' Med. the main facts, I have ventured to quote
Researches,' p. 530. this case.

36 'L'Hered. Nat.,' torn, ii., p. 850. 3S Prosper Lucas ' Hered. Nat.' torn.
97 Sedgwick, ' Brit, and For. Med.- i. p. 400.

Chirurg. Review,' April, 1861, p. 4S5. I 39 Sedgwick, idem, July, 1861, p. 202.

have seen three accounts, all taken from 40 Piorry, p. 109 ; Prosper Lucas, torn,

the same original authority (which I ii. p. 759.

have not been able to consult), and all 41 Prosper Lucas, torn. ii. p. 748.

Chap. XIV. AT CORRESPONDING PERIODS. 101

in the precise nature of an inherited disease', though still affecting
(he same organ.

Asthma haa attacked several members of the same family when
forty years old, and other families during infancy. The most dif-
ferent diseases, as angina pectoris, stone in the bladder, and various
affections of the skin, have appeared in successive generations at
nearly the same age. The little finger of a man began from some
unknown cause to grow inwards, and the same finger in his two
sons began at the same age to bend inwards in a similar manner.
Strange and inexplicable neuralgic affections have caused parents
and children to suffer agonies at about the same period of life.42

I will give only two other cases, which are interesting as illus-
trating the disappearance as well as the appearance of disease at
the same age. Two brothers, their father, their paternal uncles,
seven cousins, and their paternal grandfather, were all similarly
affected by a skin-disease, called pityriasis versicolor ; " the disease,
strictly limited to the males of the family (though transmitted
through the females), usually appeared at puberty, and disappeared
at about the age of forty or forty-five years." The second case is
that of four brothers, who when about twelve years old suffered
almost every week from severe headaches, which were relieved
only by a recumbent position in a dark room. Their father, pa-
ternal uncles, paternal grandfather, and paternal granduncles all
suffered in the same way from headaches, which ceased at the age
of fifty-four or fifty-five in all those who lived so long. None of
the females of the family were affected.43

It is impossible to read the foregoing accounts, and
the many others which have been recorded, of diseases
coming on during three or even more generations, at the
same age in several members of the same family, espe-
cially in the case of rare affections in which the coinci-
dence cannot be attributed to chance, and doubt that
there is a strong tendency to inheritance in disease at
corresponding periods of life. When the rule fails, the
disease is apt to come on earlier in the child than in the
parent ; the exceptions in the other direction being very

42 Prosper Lucas, torn. ii. pp. 678, 700, 43 These cases are given by Mr. Sedg-

702 ; Sedgwick, idem, April, 1863, p. 449, w ick, on the authority of Dr. H. Stewart,

and July, 1863, p. 162; D*r. J. Steinan, in 'Med.-Chirurg. Review,' April, 1863,

' Essay on Hereditary Disease,' 1843, pp. pp. 449, 477.
27,34.

102 INHERITANCE. Chap. XIV.

much rarer. Dr. Lucas 44 alludes to several cases of in-
herited disease coming on at an earlier period. I have
already given one striking instance with blindness dur-
ing three generations; and Mr. Bowman remarks that
this frequently occui-s Avith cataract. With cancer there
seems to be a peculiar liability to earlier inheritance:
Mr. Paget, who has particularly attended to this subject,
and tabulated a large number of cases, informs me that
he believes that in nine cases out of ten the later gene-
ration suffers from the disease at an earlier period than
the previous generation. He adds, "In the instances in
which the opposite relation holds, and the members of
later generations have cancer at a later age than their
predecessors, I think it will be found that the non-can-
cerous parents have lived to extreme old ages." So that
the longevity of a non-affected parent seems to have the
power of determining in the offspring the fatal period ;
and we thus apparently get another element of complex-
ity in inheritance.

The facts, showing that with certain diseases the period
of inheritance occasionally or even frequently advances,
are important with respect to the general descent-theory,
for they render it in some degree probable that the same
thing would occur with ordinary modifications of struc-
ture. The final result of a long series of such advances
would be the gradual obliteration of characters proper
to the embryo and larva, which would thus come to re-
semble more and more closely the mature parent-form.
But any structure which was of service to the embryo or
larva would be preserved by the destruction at this stage
of growth of each individual which manifested any ten-
dency to lose at too early an age its own proper cha-
racter.

Finally, from the numerous races of cultivated plants
and domestic animals, in which the seed or esrsrs, the

** 'Hgred. Nat.,' torn. ii. p.

Chap. XIV.

SUMMARY. 103

young or old, differ from each other and from their pa-
rent-species; — from the cases in which new characters
have appeared at a particular period, and afterwards
have been inherited at the same period ; — and from what
we know with respect to disease, we must believe in the
truth of the great principle of inheritance at correspond-
ing periods of life.

Summary of the three preceding Chapters. — Strong as
is the force of inheritance, it allows the incessant appear-
ance of new characters. These, whether beneficial or
injurious, of the most trifling importance, such as a shade
of colour in a flower, a coloured lock of hair, or a mere
gesture ; or of the highest importance, as when affecting
the brain or an organ so perfect and complex as the eye ;
or of so grave a nature as to deserve to be called a mon-
strosity, or so peculiar as not to occur normally in any
member of the same natural class, are all sometimes
strongly inherited by man, the lower animals, and plants.
In numberless cases it suffices for the inheritance of a
peculiarity that one parent alone should be thus charac-
terised. Inequalities in the two sides of the body, though
opposed to the law of symmetry, may be transmitted.
There is a considerable body of evidence showing that
even mutilations, and the effects of accidents, especially
or perhaps exclusively when followed by disease, are
occasionally inherited. There can be no doubt that the
evil effects of long-continued exposure in the parent to
injurious conditions are sometimes transmitted to the
offspring. So it is, as we shall see in a future chapter,
with the effects of the use and disuse of parts, and of
mental habits. Periodical habits are likewise transmit-
ted, but generally, as it would appear, with little force.

Hence we are led to look at inheritance as the rule, and
non-inheritance as the anomaly. But this power often
appears to us in our ignorance to act capriciously, transmit-
ting a character with inexplicable strength or feebleness.

104 INHERITANCE. Chap. XIV.

The very same peculiarity, as the weeping liabit of trees,
silky-feathers, &c, may be inherited either firmly or not at
all by different members of the same group, and even by dif-
ferent individuals of the same species, though treated in the
same manner. In this latter case we see that the power
of transmission is a quality which is merely individual in
its attachment. As with single characters, so it is with
the several concurrent slight differences which distinguish
sub-varieties or races ; for of these, some can be propa-
gated almost as truly as species, whilst others cannot be
relied on. The same rule holds good with plants, when
propagated by bulbs, offsets, &c, which in one sense still
form parts of the same individual, for some varieties re-
tain or inherit through successive bud-generations their
character far more truly than others.

Some characters not proper to the parent-species have
certainly been inherited from an extremely remote epoch,
and may therefore be considered as firmly fixed. But it
is doubtful whether length of inheritance in itself gives
fixedness of character; though the chances are obviously
in favour of any character which has long been trans-
mitted true or unaltered, still being transmitted true as
long as the conditions of life remain the same. We know
that many species, after having retained the same cha-
racter for countless ages, whilst living under their natural
conditions, when domesticated have varied in the most
diversified manner, that is', have failed to transmit their
original form ; so that no character appears to be ab-
solutely fixed. "We can sometimes account for the failure
of inheritance by the conditions of life being opposed to
the development of certain characters ; and still oftener,
as with plants cultivated by grafts and buds, by the con-
ditions causing new and slight modifications incessantly
to appear. In this latter case it is not that inheritance
wholly fails, but that new characters are continually
superadded. In some few cases, in which both parents
are similarly characterised, inheritance seems to gain so

Chap. XIV. SUMMARY. 105

much force by the combined action of the two parents,
that it counteracts its own power, and a new modification
is the result.

In many cases the failm-e of the parents to transmit
their likeness is due to the breed having been at some
former period crossed; and the child takes after his
grandparent ,or more remote ancestor of foreign blood.
In other cases, in which the breed has not been crossed,
but some ancient character has been lost through varia-
tion, it occasionally reappears through reversion, so that
the parents apparently fail to transmit their own likeness.
In all cases, however, we may safely conclude that the
child inherits all its characters from its parents, in whom
certain characters ai'e latent, like the secondary sexual
characters of one sex in the other. When, after a long
succession of bud-generations, a flower or fruit becomes
separated into distinct segments, having the colours or
other attributes of both parent-forms, we cannot doubt
that these characters were latent in the earlier buds,
though they could not then be detected, or could be de-
tected only in an intimately commingled state. So it is
with animals of crossed parentage, which with advancing
years occasionally exhibit characters derived from one of
their two parents, of which not a trace could at first be
perceived. Certain monstrosities, which resemble what
naturalists call the typical form of the group in question,
apparently come under the same law of reversion. It is
assuredly an astonishing fact that the male and female
sexual elements, that buds, and even full-grown animals,
should retain characters, during several generations in
the case of crossed breeds, and during thousands of gen-
erations in the case of pure breeds, written as it were in
invisible ink, yet ready at any time to be evolved under
the requisite conditions.

What these conditions are, we do not in many cases
at all know. But the act of crossing in itself, apparently
from causing some disturbance in the organisation, cer-

106 INHERITANCE. Chap. XIV.

tainly gives a strong tendency to the reappearance of
long-lost characters, both corporeal and mental, indepen-
dently of those derived from the cross. A return of any
species to its natural conditions of life, as with feral ani-
mals and plants, favours reversion ; though it is certain
that this tendency exists, we do not know how far it pre-
vails, and it has been much exaggerated. .On the other
hand, the crossed offspring of plants which have had their
organisation disturbed by cultivation, are more liable to
reversion than the crossed offspring of species which have
always lived under their natural conditions.

When distinguishable individuals of the same family,
or races, or species are crossed, we see that the one is
often prepotent over the other in transmitting its own
character. A race may possess a strong power of inherit-
ance, and yet when crossed, as we have seen with trum-
peter-pigeons, yield to the prepotency of every other race.
Prepotency of transmission may be equal in the two sexes
of the same species, but often runs more strongly in one sex.
It plays an important part in determining the rate at
which one race can be modified or wholly absorbed by
repeated crosses with another. We can seldom tell what
makes one race or species prepotent over another ; but it
sometimes depends on the same character being present
and visible in one parent, and latent or potentially present
m the other.

Characters may first appear in either sex, but oftener in
the male than in the female, and afterwards be transmitted
to the offspring of the same sex. In this case we may feel
confident that the peculiarity in question is really present
though latent in the opposite sex ; hence the father may
transmit through his daughter any character to his grand-
son ; and the mother conversely to her granddaughter.
We thus learn, and the fact is an important one, that
transmission and development are distinct powers. Occa-
sionally these two powers seem to be antagonistic, or
incapable of combination in the same individual; for

Chap. XIV.

SUMMARY. 107

several eases have been recorded in which the son lias
not directly inherited a character from his lather, or
directly transmitted it to his son, but has received it
by transmission through his non-affected mother, and
transmitted it through his non-affected daughter. Owing
to inheritance being limited by sex, we can see how sec-
ondary sexual characters may first have arisen under
nature ; their preservation and accumulation being depen-
dent on their .service to either sex.

At whatever period of life a new character first appears,
it generally remains latent in the offspring until a corre-
sjxmding age is attained, and then it is developed. When
this rule fails, the child generally exhibits the character
at an earlier period than the parent. On this principle
of inheritance at corresj^onding periods, we can under-
stand how it is that most animals display from the germ
to maturity such a marvellous succession of characters.

Finally, though much remains obscure with respect to
Inheritance, we may look at the following laws as fairly
well established. Firstly, a tendency in every character,
new and old, to be transmitted by seminal and bud gene-
ration, though often counteracted by various known and
unknown causes. Secondly, reversion or atavism, which
depends on transmission and development being distinct
powers : it acts in various degrees and manners through
both seminal and bud generation. Thirdly, prepotency
of transmission, which may be confined to one sex, or be
common to both sexes of the prepotent form. Fourthly,
transmission, limited by sex, generally to the same sex in
which the inherited character first appeared. Fifthly,
inheritance at corresponding periods of life, with some
tendency to the earlier development of the inherited cha-
racter. In these laws of Inheritance, as displayed under
domestication, we see an ample provision for the produc-
tion, through variability and natural selection, of new
specific forms.

108 ON CROSSING. Chap. XV.

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 TRANSMIS-
SION, BY THE CONDITIONS OF LIFE, AND BY NATURAL SELECTION
— ALL ORGANIC BEINGS OCCASIONALLY INTERCROSS ; APPARENT
EXCEPTIONS — ON CERTAIN CHARACTERS INCAPABLE OF FU-
SION ; CHIEFLY OR EXCLUSIVELY THOSE WHICH HAVE SUD-
DENLY APPEARED IN THE INDIVIDUAL — ON THE MODIFICATION
OF OLD RACES, AND THE FORMATION OF NEW RACES, BY CROSS-
ING— SOME CROSSED RACES HAVE BRED TRUE FROM THEIR
FIRST PRODUCTION — ON THE CROSSING OF DISTINCT SPECIES
IN RELATION TO THE FORMATION OF DOMESTIC RACES.

In the two previous chapters, when discussing reversion
and prepotency, I was necessarily led to give many facts
on crossing. In the present chapter I shall consider the
part which crossing plays in two opposed directions, —
firstly, in obliterating characters, and consequently in
preventing the formation of new races ; and secondly,
in the modification of old races, or in the formation of
new and intermediate races, by a combination of charac-
ters. I shall also show that certain characters are inca-
pable of fusion.

The efiects of free or uncontrolled breeding between
the members of the same variety or of closely- allied
varieties are important ; but are so obvious that they
need not be dfScussed at much length. It is free inter-
crossing which chiefly gives uniformity, both under nature

Chap. XV. ON CKOSSING. 109

and under domestication, to the individuals of the same
species or variety, when they live mingled together and
are not exposed to any cause inducing excessive varia-
bility. The prevention of free crossing, and the inten-
tional matching of individual animals, are the corner-
stones of the breeder's art. No man in his senses would
expect to improve or modify a breed in any particular
manner, or keep an old breed true and distinct, unless he
separated his animals. The killing of inferior animals
in each generation comes to the same thing as their
separation. In savage and semi-civilised countries,
where the inhabitants have not the means of separat-
ing their animals, more than a single breed of the same
species rarely or never exists. In former times, even in
a country so civilised as North America, there were no
distinct races of sheep, for all had been mingled to-
gether.1 The celebrated agriculturist Marshall2 remarks
that " sheep that are kept within fences, as well as shep-
" herded flocks in open countries, have generally a similar-
" ity, if not a uniformity, of character in the individuals of
" each flock ;" for they breed freely together, and are pre-
vented from crossing with other kinds ; whereas in the
unenclosed parts of England the unshepherded sheep,
even of the same flock, are far from true or uniform,
owing to various breeds having mingled and crossed.
We have seen that the half-wild cattle in the several
British parks are uniform in character in each ; but in
the different parks, from not having mingled and crossed
during many generations, they differ in a slight degree.
We cannot doubt that the extraordinary number of
varieties and sub-varieties of the pigeon, amounting to
at least one hundred and fifty, is partly due to their re-
maining, differently from other domesticated birds, paired
for life when once matched. On the other hand, breeds

1 Communications to the Boai"d of 2 ' Review of Reports, North of Eng-

Agriculture, vol. i. p. 367. land,' 1S03, p. 200.

110 ON CROSSING AS A CAUSE Chap. XV.

of cats imported into this country soon disappear, for
their nocturnal and rambling habits render it hardly pos-
sible to prevent free crossing. • Rengger3 gives an inte-
resting case with respect to the cat in Paraguay : in all
the distant parts of the kingdom it has assumed, appa-
rently from the effects of the climate, a peculiar character,
but near the capital this change has been prevented,
owing, as he asserts, to the native animal frequently
crossing with cats imported from Europe. In all cases
like the foregoing, the eifects of an occasional cross will
be augmented by the increased vigour and fertility of the
crossed offspring, of which fact evidence will hereafter
be given ; for this will lead to the mongrels increasing
more rapidly than the pure parent-breeds.

When distinct breeds are allowed to cr6ss freely, the
result will be a heterogeneous body ; for instance, the
dogs in Paraguay are far from uniform, and can no longer
be affiliated to their parent-races.4 The character which
a crossed body of animals will ultimately assume must
depend on several contingencies, — namely, on the relative
numbers of the individuals belonging to the two or more
races which are allowed to mingle ; on the jn-epotency of
one race over the other in the transmission of character ;
and on the conditions of life to which they are exposed.
When two commingled breeds exist at first in nearly
equal numbers, the whole will sooner or later become
intimately blended, but not so soon, both breeds being
equally favored in all respects, as might have been
expected. The following calculation5 shows that this
is the case : if a colony with an equal number of black
and white men were founded, and we assume that they
marry indiscriminately, are equally prolific, and that one
in thirty annually dies and is born ; then "in 65 years

* ' Saugethiere von Paraguay,' 1830, 6 White, ' Regular Gradation in Man,'

s. 212. p. 140.

4 Rengger, 'Saugethiere,' &c, s. 154.

Cmr. xv. OF UNIFORMITY OF CHARACTER. Ill

"the number of blacks, whites, and mulattoes Avould be
"equal. In 91 years the whites would be l-10th, the
" blacks l-10th, and the mulattoes, or people of interme-
"diate degrees of color, 8-10ths of the whole number.
"In three centuries not l-100th part of the whites would
" exist."

When one of two mingled races exceeds the other
greatly in number, the latter will soon be wholly, or
almost wholly, absorbed and lost.9 Thus European pigs
and dogs have been largely introduced into the islands
of the Pacific Ocean, and the native races have been
absorbed and lost in the course of about fifty or sixty
years ;7 but the imported races no doubt were favored.
Rats may be considered as semi-domesticated animals.
Some snake- rats (Jfus alexcmdrinus) escaped in the
Zoological Gardens of London, " and for a long time
" afterwards the keepers frequently caught cross-bred
" rats, at first half-breds, afterwards with less and less of
" the character of the snake-rat, till at length all traces
" of it disappeared." 8 On the other hand, in some parts
of London, especially near the docks, where fresh rats
are frequently imported, an endless variety of interme-
diate forms may be found between the brown, black, and
snake-rat, which are all three usually ranked as distinct
species.

How many generations are necessary for one species
or race to absorb another by repeated crosses has often
been discussed ,9 and the requisite number has probably
been much exaggerated. Some writers have maintained
that a dozen, or score, or even more generations, are

• Dr. W. F. Edwards, in his ■ Charac- Soc.,' vol. vi., 1862, p. 71.
teres Physiolog. des Races Humaines,' 9 Sturm, ' Ueber Racen, &c.,' 1825, s.

p. 23, first called attention to this sub- 107. Bronn, ' Geschichte der Natur,'

ject, and ably discussed it. b. ii. s. 170, gives a table of the propor-

7 Rev. D. Tyerraan, and Bennett, tions of blood after successive crosses.
'Journal of Voyages,' 1S21-1S29, vol. i. Dr. P. Lucas, ' l'Hcrddito Nat.,' torn. ii.
p. 300. p. 30S.

8 Mr. S. J. Salter, ' Journal Linn.

112 ON CROSSING AS A CAUSE Chap. XV.

necessary ; but this in itself is improbable, for in the
tenth generation there will be only 1-1 024th part of
foreign blood in the offspring. Gartner found,10 that
with plants one species could be made to absorb another
in from three to five generations, and he believes that
this could always be effected in from six to seven genera-
tions. In one instance, however, Kolreuter " speaks of
the offspring of Mirabilis vulgaris, crossed during eight
successive generations by M. longiflora, as resembling
this latter species so closely, that the most scrupulous
observer could detect " vix aliquam notabilem differen-
tiam ; " — he succeeded, as he says, " ad plenariam fere
transmutationem." But this expression shows that the
act of absorption was not even then absolutely complete,
though these crossed plants contained only the 1- 256th
part of M. vulgaris. The conclusions of such accurate
observers as Gartner and Kolreuter are of far higher
worth than those made without scientific aim by
breeders. The most remarkable statement which I have
met with of the persistent endurance of the effects of a
single cross is given by Fleischmann,12 wTho, in reference
to German sheep, says " that the original coarse sheep
" have 5500 fibres of wool on a square inch ; grades of
" the third or fourth Merino cross produced about 8000,
" the twentieth cross 27,000, the perfect pure Merino
" blood 40,000 to 48,000." So that in this case common
German sheep crossed twenty times successively with
Merinos have not by any means acquired wool as fine as
that of the pure breed. In all cases the rate of absorp-
tion will depend largely on the conditions of life being
favourable to any particular character ; and we may
suspect that there would be under the climate of
Germany a constant tendency to degeneration in the

10 ' Bastarderzeugung,' s. 463, 470. 12 As quoted in the ' True Principles

11 ' Nova Acta Petrop.,' 1794, p. 393: of Breeding,' by C. H. Macknight and
Bee also previous volume. Dr. H. Madden, 1SG5, p. 11.

Chap. XV. OF UNIFORMITY OF CHARACTER. 113

wool of Merinos, unless prevented by careful selection;
and thus perhaps the foregoing remarkable case may be
explained. ' The rate of absorbtion must also depend on
the amount of distinguishable difference between the
two forms which are crossed, and especially, as Gartner
insists, on prepotency of transmission in the one form
over the other. We have seen in the last chapter that
one of two French breeds of sheep yielded up its
character, when crossed with Merinos, very much
slower than the other ; and the common German sheep
referred to by Fleischmann may present an analogous
case. But in all cases there will be during many subse-
quent generations more or less liability to reversion, and
it is this fact which has probably led authors to maintain
that a score or more of generations are requisite for one
race to absorb another. In considering the final result
of the commingling of two or more breeds, we must not
forget that the act of crossing in itself tends to bring
back long-lost characters not proper to the immediate
parent-forms.

With respect to the influence of the conditions of life
on any two breeds which are allowed to cross freely,
unless both are indigenous and have long been accustom-
ed to the country where they live, they will, in all
probability, be unequally affected by the conditions, and
this will modify the result. Even with indigenous
breeds, it will rarely or never occur that both are equally
well adapted to the surrounding circumstances ; more
especially when permitted to roam freely, and not care-
fully tended, as will generally be the case with breeds
allowed to cross. As a consequence of this, natural se-
lection will to a certain extent come into action, and the
best fitted will survive, and this will aid in determining
the ultimate character of the commingled body.

How long a time it would require before such a crossed
body of animals would assume within a limited area a
uniform character no one can say ; that they would ulti-

114 ON ALL ORGANIC BEINGS Chap. XV.

mately become uniform from free intercrossing, and from
the survival of the fittest, Ave may feel assured; but the
character thus acquired would rarely or never* as we may
infer from the several previous considerations, be exactly
intermediate between that of the two parent-breeds.
With respect to the very slight differences by which
the individuals of the same sub-variety, or even of allied
varieties, are characterised, it is obvious that free cross-
ing would soon obliterate such small distinctions. The
formation of new varieties, independently of selection,
would also thus be prevented; except when the same
variation continually recurred from the action of some
strongly predisposing cause. Hence we may conclude
that free crossing has in all cases played an important
part in giving to all the members of the same domestic
race, and of the same natural species, uniformity of cha-
racter, though largely modified by natural selection and
by the direct action of the surrounding conditions.

On the 2^ossibility of all organic beings occasionally
intercrossing. — But it may be asked, can free crossing
occur with hermaphrodite animals and plants ? All the
higher animals, and the few insects which have been do-
mesticated, have separated sexes, and must inevitably
unite for each birth. With respect to the crossing of
hermaphrodites, the subject is too large for the present
volume, and will be more properly treated in a succeed-
ing work. In my ' Origin of Species,' however, I have
given a short abstract of the reasons which induced me
to believe that all organic beings occasionally cross,
though perhaps in some cases only at long intervals of
time.13 I will here just recall the fact that many plants,
though hermaphrodite in " structure, are unisexual in
function ; — such as those called by C. K. Sprengel clicho-

13 With respect to plants, an admirable lately been published by Dr. Hildebrand,
essay on this subject (Die Geschlechter- who arrives at the same general con-
Vertheilung bei den Pflanzen : 1867) has elusions as I have done.

Ohap. XV. OCCASIONALLY INTERCROSSING. 115

gamous, in which the pollen and stigma of the same
flower arc matured at different periods ; or those called
by me reciprocally dimorj+hic, in which the flower's own
pollen is not fitted to fertilise its own stigma ; or again,
the many kinds in which curious mechanical contrivances
exist, effectually preventing self-fertilisation. There are,
however, many hermaphrodite plants which are not in
any way specially constructed to favour intercrossing,
but which nevertheless commingle almost as freely as
animals with separated sexes. This is the case with
cabbages, radishes, and onions, as I know from having
experimented on them : even the peasants of Liguria say
that cabbages must be prevented "from falling in love"
with each other. In the orange tribe, Gallesio14 remarks
that the amelioration of the various kinds is checked by
their continual and almost regular crossing. So it is with
numerous other plants.

Nevertheless some cultivated plants can be named
which rarely intercross, as the common pea, or which
never intercross, as I have reason to believe is the case
with the sweet-pea {Lathyrus odoratus) ; yet the struc-
ture of these flowers certainly favours an occasional cross.
The varieties of the tomato and aubergine {Solatium) and
pimenta {Pimenta vidgaris?) are said15 never to cross,
even when growing alongside each other. But it should
bo observed that these are all exotic plants, and we do
not know how they would behave in their native country
when visited by the proper insects.

It must also be admitted that some few natural species
appear under our present state of knowledge to be per-
petually self-fertilised, as in the case of the Bee Ophrys
(0. apifera), though adapted in its structure to be occa-
sionally crossed. The Leersia oryzoides produces minute
enclosed flowers which cannot possibly be crossed, and

14 ' Teoriadella Riproduzione Vegetal,' 181 G, p. 12.
18 Verlot, ' Des Varietes,' 1S65, p. 72.

116 ON CERTAIN CHARACTERS Chap. XV.

these alone, to the exclusion of the ordinary flowers, have
as yet been known to yield seed.16 A few additional and
analogous cases could be advanced. But these facts do
not make me doubt that it is a general law of nature that
the individuals of the same species occasionally intercross,
and that some great advantage is derived from this act.
It is well known (and I shall hereafter have to give in-
stances) that some plants, both indigenous and natural-
ised, rarely or never produce flowers ; or, if they flower,
never produce seeds. But no one is thus led to doubt
that it is a general law of nature that phanerogamic plants
should produce flowers, and that these flowers should
produce seed. When they fail, we believe that such
plants would perform their proper functions under differ-
ent conditions, or that they formerly did so and will do so
again. On analogous grounds, I believe that the few
flowers which do not now intercross, either would do so un-
der different conditions, or that they formerly fertilised each
other at intervals — the means for effecting this being gen-
erally still retained — and they will do so again at some
future period, unless indeed they become extinct. On
this view alone, many points in the structure and action
of the reproductive organs in hermaphrodite plants and
animals are intelligible, — for instance, the male and female
organs never being . so completely enclosed as to render
access from without impossible. Hence we may conclude
that the most important of all the means for giving uni-
formity to the individuals of the same sj>ecies, namely, the
capacity of occasionally intercrossing, is present, or has
been formerly present, with all organic beings.

On certain Characters not Wending. — When two breeds are crossed
their characters usually become intimately fused together ; but some
characters refuse to blend, and are transmitted in an unmodified state
either from both parents or from one. When grey and white mice
are paired, the young are not piebald nor of an intermediate tint, but

18 Duval-Jouve, ' Bull. Soc. Bot. de France,' torn, x., 1868, p. 194.

Chap. XV. NOT BLENDING. 117

are pure white or of the ordinary grey colour : so it is when white
and common pollared turtle-doves are paired. In breeding Game
fowls, a great authority, Mr. J. Douglas, remarks, " I may here state
a strange fact : if you cross a black with a white frame, you get
birds of both breeds of the clearest colour." Sir R. Heron crossed
during many years white, black, brown, and fawn-coloured Angora
rabbits, and never once got these colours mingled in the same ani-
mal, but often all four colours in the same litter." Additional cases
could be given, but this form of inheritance is very far from univer-
sal even with respect to the most distinct colours. When turnspit
di igs and ancon sheep, both of which have dwarfed limbs, are tossed
with common breeds, the offspring are not intermediate in structure,
but take after either parent. When tailless or hornless animals are
crossed with perfect animals, it frequently, but by no means invari-
ably, happens that the offspring are either perfectly furnished with
these organs or are quite destitute of them. .According to Rengger,
the hairless condition of the Paraguay dog is eitlier*perfectly or not
at all transmitted to its mongrel offspring ; but I have seen one par-
tial exception in a dog of this parentage which had part of its skin
hairy, and part naked ; the parts being distinctly separated as in a
piebald animal. When Dorking fowls with five toes are crossed
with other breeds, the chickens often have five toes on one foot and
four on the other. Some crossed pigs raised by Sir R. Heron be-
tween the solid-hoofed and common pig had not all four feet in an
intermediate condition, but two feet were furnished with properly
divided, and two with united hoofs.

Analogous facts have been observed with plants : Major Trevor
Clarke crossed the little, glabrous-leaved, annual stock (Matthiola),
with pollen of a large, red-flowered, rough-leaved, biennial stock,
called cocardean by the French, and the result was that half the
seedlings had glabrous and the other half rough leaves, but none
had leaves in an intermediate state. That the glabrous seedlings

17 Extract of a letter from Sir R. lie- crossed South American dogs, see Ueng-

ron, 1838, given me by Mr. Yarrell. With ger, ' Saugethiere von Paraguay,' s. 153 :

respect to mice, see 'Annal. des Sc. Nat.,' but I saw in the Zoological Gardens,

torn. i. p. ISO; and I have heard of other mongrels, from a similar cross, which

similar cases. For turtle-doves, Boitard were hairless, quite hairy, or hairy in

and Corbie, ' Les Pigeons,' Sec, p. 23S. patches, that is, piebald with hair. For

For t lie (lame fowl, ' The Poultry Boot,' crosses of Dorking and other fowls, see

1SG6, p. 12?. For crosses of tailless fowls, 'Poultry Chronicle,'" vol. ii. p. 855.

see Bechstein, ' Xaturges. Deutsch.1 b. iii. About, the crossed pigs, extract of letter

s. 403. Brown, ' Geschichte der (Tatar, ' from Sir K. Heron to Mr. Yarrell. For

b. ii. s. 170, gives analogous facts with other cases, see P. Lucas, ' Uurod. Nat.,'

horses. On the hairless condition of torn. i. p. 212.

118 OJS" CERTAIN CHARACTERS Chap. XV.

were the product of the rough-leaved variety, and not accidentally
of the mother-plant's own pollen, was shown by their tall and
strong habit of growth.18 In the succeeding generations raised
from the rough-leaved crossed seedlings, some glabrous plants ap-
peared, showing that the glabrous character, though incapable of
blending with and modifying the rough leaves, was all the time
latent in this family of plants. The numerous plants formerly re-
ferred to, which I raised from reciprocal crosses between the peloric
and common Antirrhinum, offer a nearly parallel case ; for in the
first generation all the plants resembled the common form, and in
the next generation, out of one hundred and thirty-seven plants,
two alone were in an intermediate condition, the others perfectly
resembling either the peloric or common form. Major Trevor
Clarke also fertilised the above-mentioned red-flowered stock with
pollen from the purple Queen stock, and about half, the seedlings
scarcely differed in habit, and not at all in the red colour of the
flower, from the mother-plant, the other half bearing blossoms of
a rich purple, closely like those of the paternal plant. Gartner
crossed many white and yellow-flowered species and varieties of
Verbascmn ; and these colours were never blended, but the off-
spring bore either pure white or pu?e yellow blossoms ;" the former
in the larger proportion.19 Dr. Herbert raised many seedlings, as
he informed me, from Swedish turnips crossed by two other varie-
ties, and these never produced flowers of an intermediate tint, but
always like one of their parents. I fertilised the purple sweet-pea
(Ldtliyrus odoratus), which has a dark reddish-purple standard-
petal and violet-coloured wings and keel, with pollen of the painted-
lady sweet-pea, which lias a pale cherry-coloured standard, and
almost white wings and keel ; and from the same pod I twice
raised plants perfectly resembling both sorts ; the greater number
resembling the father. So perfect was the resemblance, that I
should have thought there had been some mistake, if the plants
which were at first identical with the paternal variety, namely, the
painted-lady, had not later in the season produced, as mentioned in
a former chapter, flowers blotched and streaked with dark purple.
I raised grandchildren and great-grandchildren from these crossed
plants, and they continued to resemble the painted-lady, but during
the later generations became rather more blotched with purple, yet

18 'Internat. Hort. and Hot. Congress from similar crosses id the genus Ver-
of London,' 1S66. bascum. With respect to the turnips,

19 ' Bastarderzeugung,' s. 807. Kol- see Herbert's ' Amaryllidacece,' 1S37, p.
reuter (' Dritte Fortsetzung,' s. 34, 311), 3T0.

however, obtained intermediate tints

Chap. XV. NOT BLENDING. 119

none reverted completely to the original mother-plant, the purple
sweet-pea, The following case is slightly different, but still shows
the same principle : Naudin"0 raised numerous hybrids between the
yellow Li/inrii! vulgaris and the purple L. purpurea, and during
three successive generations the colours kept distinct in different
parts of the same flower.

From such cases as the foregoing, in which the offspring of the
first generation perfectly resemble either parent, we come by a
small step to those cases in which differently coloured flowers
borne on the same root resemble both parents, and by another step
to those in which the same flower or fruit is striped or blotched
■with the two parental colours, or bears a single stripe of the colour
or other characteristic quality of one of the parent-forms. With
hybrids and mongrels it frequently or even generally happens that
one part of the body resembles more or less closely one parent and
another part the other parent ; and here again some resistance to
fusion, or, what comes to the same thing, some mutual affinity be-
tween the organic atoms of the same nature, apparently comes into
play, for otherwise all parts of the body would be equally interme-
diate in character. So again, when the offspring of hybrids or mon-
grels, which are themselves nearly intermediate in character, revert
either wholly or by segments to their ancestors, the principle of
the affinity or similar, or the repulsion of dissimilar atoms, must
come into action. To this principle, which seems to be extremely
general, we shall recur in the chapter on pangenesis.

It is remarkable, as has been strongly insisted upon by Isidore
Geoft'roy St. Hilaire in regard to animals, that the transmission of
characters without fusion occurs most rarely when species are
crossed ; I know of one exception alone, namely, with the hybrids
naturally produced between the common and hooded crow {Corvus
corone and comix), which, however, are closely allied species, differ-
ing in nothing except colour. Nor have I met with any well-ascer-
tained cases of transmission of this kind, even when one form is
strongly prepotent over another, when two races are crossed which
have been slowly formed by man's selection, and therefore resemble
to a certain extent natural species. Such cases as puppies in the
same litter closely resembling two distinct breeds, are probably
due to superfoetation, — that is, to the influence of two fathers. All
the characters above enumerated, which are transmitted in a per-
fect state to some of the offspring and not to others, — such as dis-
tinct colours, nakedness of skin, smoothness of leaves, absence of
horns or tail, additional toes, pelorism, dwarfed structure, fie, —

•o ' Nouvelles Archives du Museum,' torn. i. p. 100.

120 ON CROSSING AS A CAUSE Chap. XV.

have all been known to appear suddenly in individual animals and
plants. From this fact, and from the several slight, aggregated
differences which distinguish domestic races and species from each
other, not being liable to this peculiar form of transmission, we
may conclude that it is in some way connected with the sudden
appearance of the characters in question.

On the Modification of old Races and the Formation
of new Races by Grossing. — We have hitherto chiefly
considered the effects of crossing in giving uniformity of
character ; we must now look to an opposite result. There
can he no doubt that crossing, with the aid of rigorous
selection during several generations, has been a potent
means in modifying old races, and in forming new ones.
Lord Orford crossed his famous stud of greyhounds once
with the bulldog, which breed was chosen from being
deficient in scenting powers, and from having what was
wanted, courage and perseverance. In the course of six
or seven generations all traces of the external form of the
bulldog were eliminated, but courage and perseverance"
remained. Certain pointers have been crossed, as I hear
from the Rev. W. D. Fox, with the foxhound, to give
them dash and speed. Certain strains of Dorking fowls
have had a slight infusion of Game blood ; and I have
known a great fancier who on a single occasion crossed
his turbit-pigeons with barbs, for the sake of gaining
greater breadth of beak.

In the foregoing cases breeds have been crossed once,
for the sake of modifying some particular character; but
with most of the improved races of the pig, which now
breed true, there have been repeated crosses, — for in-
stance, the improved Essex owes its excellence to re-
peated crosses with the Neapolitan, together probably
with some infusion of Chinese blood.21 So with our Bri-
tish sheep : almost all the races, except the Southdown,

« Richardson, 'Pigs,' 1S4T, pp. ST, 42; S. Sidney's edition of ' Youatt on the Pig,'
560. i). 3.

1860, p. 3.

Chap. XV. OF THE MODIFICATION OF RACES. 121

have been largely crossed ; " this, in fact, has been the
history of our principal breeds."32 To give an example,
the "Oxfordshire Downs" now rank as an established
breed." They were produced about the year 1830 by
crossing "Hampshire and in some instances Southdown
ewes with Cotswold rams:" now the Hampshire ram
was itself produced by repeated crosses between the
native Hampshire sheep and Southdowns; and the long-
woolled Cotswold were improved by crosses with the
Leicester, which latter again- is believed to have been a
cross between several long-woolled sheep. Mr. Spooner,
after considering the various cases which have been care-
fully recorded, concludes, "that from a judicious pairing
of cross-bred animals it is practicable to establish a new
breed." On the Continent the history of several crossed
races of cattle and of other animals has been well ascer-
tained. To give one instance : the King of Wurtembercr,
after twenty-five years' careful breeding, that is after six
or seven generations, made a new breed of cattle from a
cross between a Dutch and Swiss breed, combined with
other breeds.54 The Sebright bantam, which breeds as
true as any other kind of fowl, was formed about sixty
years ago by a complicated cross." Dark Brahmas, which
are believed by some fanciers to constitute a distinct spe-
cies, Avere undoubtedly formed26 in the United States,
within a recent period, by a cross between Chittagongs
and Cochins. With plants I believe there is little doubt
that some kinds of turnips, now extensively cultivated,
are crossed races ; and the history of a variety of wheat
which was raised from two very distinct varieties, and

22 See Mr. W. C. Spooner's excellent 24 ' Bulletin de la Soc. d'AccIimat,,'
paper on Cross-Breedingr, 'Journal Roy- 1862, torn. ix. p. 463. See also, for other
al Asricnlt. Soc.,' vol. xx., part ii. . see cases. MM. Moll and Gayot, ' Du Boeuf,'
al«o an equally {rood article by Mr. Ch. I860, p. xxxii.

Hownrd, in 'Gardener's Chronicle,' 1S60, as 'Poultry Chronicle,' vol. ii., 1S54,

p. 320. p. 30.

23 'Gardener's Chronicle,' 1S57, pp. 28 'The Poultry Book,' by W. B. Te-
C49, 652. getmeier, 1866, p. 53.

122 ON CROSSING AS A CAUSE Chap. XV.

which after six years' culture presented an even sample,
lias been recorded on good authority.27

Until cpiite lately, cautious and experienced breeders,
though not averse to a single infusion of foreign blood,
were almost universally convinced that the attempt to
establish a new race, intermediate between two widely
distinct races, was hopeless: "they clung with super-
" stitious tenacity to the doctrine of purity of bloGd, be-
" lieving it to be the ark in which alone true safety could
"be found."28 Nor was this conviction unreasonable:
when two distinct races are crossed, the offspring of the
first generation are generally nearly uniform in charac-
ter; but even this sometimes fails to be the case, espe-
cially with crossed dogs and fowls, the young of which
from the first are sometimes much diversified. As cross-
bred animals are generally of large size and vigorous,
they have been raised in great numbers for immediate
consumption. But for breeding they are found to be ut-
terly useless; for though they may be themselves uniform
in character, when paired together they yield during many
generations offspring astonishingly diversified. The breed-
er is driven to despair, and concludes that he will never
form an intermediate race. But from the cases already
given, and from others which have been recorded, it ap-
pears that patience alone is necessary ; as Mr. Spooner
vemarks, "nature opposes no barrier to successful ad-
mixture ; in the course of time, by the aid of selection
and careful weeding, it is practicable to establish a new
breed." After six or seven generations the hoped-for re-
sult will in most cases be obtained ; but even then an
occasional reversion, or failure to keep true, may be ex-
pected. The attempt, however, will assuredly fail if the
conditions of life be decidedly unfavourable to the charac-
ters of either parent-breed.23

»» ' Gardener's Chronicle, 1852, p. 765. 29 See Colin's ' Traite de Phys. Corap.

28 Spooner, in 'Journal Royal Agri- des Aniinaux Domestiques,' torn. ii. p.
cult. Soc.,' vol. xx., part ii. 536, where this subject is well treated.

Chap. XV. OF THE MODIFICATION OF RACES. 123

Although the grandchildren and succeeding genera-
tions of cross-bred animals are generally variable in an
extreme degree, some curious exceptions to the rule have
lieen observed, both with crossed races and species.
Thus Boitard and Corbie 30 assert that from a Pouter and
a Hunt " a Cavalier will appear, which we have classed
amongst pigeons of pure race, because it transmits all
its qualities to its posterity." The editor of the ' Poultry
Chronicle ' 31 bred some bluish fowls from a black Spanish
cock aud a Malay hen ; and these remained true to colour
" generation after generation." The Himalayan breed
of rabbits was certainly formed by crossing two sub-
varieties of the silver-grey rabbit ; although it suddenly
assumed its present character, which differs much from
that of either parent-breed, yet it has ever since been
easily and truly propagated. I crossed some Labrador
and Penguin ducks, and recrossed the mongrels with
Penguins; afterwards most of the clucks reared during
three generations were nearly uniform in character, being
brown with a white crescentic mark on the lower part of
the breast, and with some white spots at the base of the
beak ; so that by the aid of a little selection a new breed
might easily have been formed. In regard to crossed
varieties of plants, Mr. Beaton remarks 32 that " Melville's
extraordinary cross between the Scotch kale and an early
cabbage is as true and genuine as any on record;" but in
this case no doubt selection was practised. Gartner 3S
has given five cases of hybrids, in which the progeny
kept constant ; and hybrids between Dianthus armeria
and delloides remained true and uniform to the tenth
generation. Dr. Herbert likewise showed me a hybrid
from two species of Loasa which from its first production
had kept constant .during several generations.

We have seen in the earlier chapters, that some of our

80 ' Les Pigeons,' p. 37. 82 ' Cottage Gardener,' 1S56, p. 110.

81 Yol. 1., ISM, p. 101. 88 ' BastarJerzeugung,' 8. 553.

124 ON CROSSING AS A CAUSE Chap. XV.

domesticated animals, such as dogs, cattle, pigs, &c, are
almost certainly descended from more than one species,
or wild race, if any one prefers to apply this latter term
to forms which were enabled to keep distinct in a state
of nature. Hence the crossing of aboriginally distinct
species probably came into play at an early period in the
formation of our present races. From Rutimeyer's obser-
vations there can be little doubt that this occurred with
cattle ; but in most cases some one of the forms which
were allowed to cross freely, will, it is probable, have ab-
sorbed and obliterated the others. For it is not likely
that semi-civilized men would have taken the necessary
pains to modify by selection their commingled, crossed,
and fluctuating stock. Nevertheless, those animals which
were best adapted to their conditions of life would have
survived through natural selection ; and by this means
crossing will often have indirectly aided in the formation
of primeval domesticated breeds.

Within recent times, as far as animals are concerned,
the crossing of distinct species has done little or nothing
in the formation or modification of our races. It is not
yet known whether the species of silk-moth which have
been recently crossed in France will yield permanent
races. In the fourth chapter I alluded with some hesita-
tion to the statement that a new breed, between the hare
and rabbit, called leporides, had been formed in France,
and was found capable of propagating itself; but it is
now positively affirmed 34 that this is an error. With
plants which can be multiplied by buds and cuttings,
hybridisation has done wonders, as with many kinds of
Roses, Rhododendrons, Pelargoniums, Calceolarias, and
Petunias. Nearly all these plants can be propagated by
seed; most of them freely; but extremely few or none
come true by seed.

34 Dr. Pigeaux, in 'Bull. Soc. d'Accli- 'Annals and Mag. of Nat. Hist.,' 186T,
mat.,' torn. Hi., July 1S66, as quoted in vol. xx. p. 75.

Cuap. XV. OF THE MODIFICATION OF KACES. 125

Some authors believe that crossing is the chief cause
of variability, — that is, of the appearance of absolutely
new characters. Some have gone so far as to look at it
as the sole caiise ; but this conclusion is disproved by
some of the facts given in the chapter on Bud-variation.
The belief that characters not present in either parent or
in their ancestors frequently originate from crossing is
doubtful; that they occasionally thus arise is probable;
but this subject will be more. conveniently discussed in a
future chapter on the causes of Variability.

A condensed summary of this and of the three follow-
ing chapters, together with some remarks on Hybridism,
will be given in the nineteenth chapter.

126 CAUSES WHICH CHECK Chap. XVI.

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, MEL-
ONS, AND TOBACCO, RENDERED IN SOME DEGREE MUTUALLY
STERILE — DOMESTICATION ELIMINATES THE TENDENCY TO STE-
RILITY NATURAL TO SPECIES WHEN CROSSED — ON THE INCREASED
FERTILITY OF UNCROSSED ANIMALS AND PLANTS FROM DOMESTI-
CATION AND CULTIVATION.

The domesticated races of both animals and plants, when
crossed, are with extremely few exceptions quite prolific,
— in some cases even more so than the purely bred parent-
races. The offspring, also, raised from such crosses are
likewise, as we shall see in the following chapter, generally
more vigorous and fertile than their parents. On the
other hand, species when crossed, and their hybrid off-
spring, are almost invariably in some degree sterile ; and
here there seems to exist a broad and insuperable dis-
tinction between races and species. The importance of
this subject as bearing on the origin of species is obvious;
and Ave shall hereafter recur to it.

It is unfortunate how few precise observations have
been made on the fertility of mongrel animals and plants
during several successive generations. Dr. Broca ' has

J ' Journal dePhysiolog.,' torn. It, 1859, p. 3S5.

Chap. XVI. THE CROSSING OF VARIETIES. 127

remarked that no one has observed whether, for instance,
mongrel dogs, bred inter se, are indefinitely fertile ; yet,
if a shade of infertility be detected by careful observation
in the offspring of natural forms when crossed, it is thought
that their specific distinction is proved. But so many
breeds of sheep, cattle, pigs, dogs, and poultry, have been
crossed and recrossed in various ways, that any sterility,
if it had existed, would from being injurious almost cer-
tainly have been observed. In investigating the fertility
of crossed varieties many sources of doubt occur. When-
ever the least trace of sterility between two plants, how-
ever closely allied, was observed by Kolreuter, and more
especially by Gartner, who counted the exact number of
seed in each capsule, the two forms were at once ranked
as distinct species ; and if this rule be followed, assuredly
it Avill never be proved that varieties when crossed are in
any degree sterile. We have formerly seen that certain
breeds of dogs do not readily pair together ; but no
observations have been made whether, when paired, they
produce the full number of young, and whether the latter
are perfectly fertile inter se / but, supposing that some
degree of sterility were found to exist, naturalists would
simply infer that these breeds were descended from
aboriginally distinct species; and it would be scarcely
possible to ascertain whether or not this explanation was
the true one.

The Sebright Bantam is much less prolific than any
other breed of fowls, and is descended from a cross
between two very distinct breeds, recrossed by a third
sub-variety. But it woidd be extremely rash to infer
that the loss of fertility was in any manner connected
with its crossed origin, for it may with more probability
be attributed either to long-continued close interbreed-
ing, or to an innate tendency to sterility correlated with
the absence of hackles and sickle tail-feathers.

Before giving the few recorded cases of forms, which
must be ranked as varieties, being in some degree sterile

12S CAUSES WHICH CHECK Chap. XVI.

when crossed, I may remark that other causes sometimes
interfere with varieties freely intercrossing. Thus they
may differ too greatly in size, as with some kinds of
dogs and fowls : for instance, the editor of the ' Journal
of Horticulture, &c.,' 2 says that he can keep Bantams
with the larger breeds without much danger of their
crossing, but not with the smaller breeds, such as Games,
Hamburgs, &c. With plants a difference in the period
of flowering serves to keep varieties distinct, as with
the various kinds of maize and wheat : thus Colonel Le
Couteur 3 remarks, "the Talavera wheat, from flowering
much earlier than any other kind, is sure to continue
pure." In different parts of the Falkland Islands the
cattle are breaking up into herds of different colours ;
and those on the higher ground, which are generally
white, usually breed, as I am informed by Admiral Suli-
van, three months earlier than those on the lowlands ;
and this would manifestly tend to keep the herds from
blending.

Certain domestic races seem to prefer breeding with
their own kind ; and this is a fact of some importance,
for it is a step towards that instinctive feeling which
helps to keep closely allied species in a state of nature
distinct. We have now abundant evidence that, if it
were not for this feeling, many more hybrids would
be naturally produced than is the case. We have seen
in the first chapter that the alco dog of Mexico dislikes
dogs of other breeds ; and the hairless dog of Paraguay
mixes less readily with the European races, than the
latter do with each other. In Germany the female
Spitz-dog is said to receive the fox more readily than
will other dogs ; a female Australian Dingo in England
attracted the wild male foxes. But these differences
in the sexual instinct and attractive power of the various
breeds may be wholly due to their descent from distinct

s Dec. 186S, p. 484. 3 On the Varieties of Wheat, p. 66.

Chap. XVL THE CROSSING OF VARIETIES. 129

species. In Paraguay the horses have much freedom,
and an excellent observer 4 believes that the native horses
of the same colour and size prefer associating with each
other, and that the horses which have been imported
from Entre Rios and Banda Oriental into Paraguay
likewise prefer associating together. In Circassia six
sub-races of the horse are known and have received
distinct names ; and a native proprietor of rank 5 asserts
that horses of three of these races, whilst living a free
life, almost always refuse to mingle and cross, and will
even attack each other.

It has been observed, in a district stocked with heavy
Lincolnshire and light Norfolk sheep, that both kinds,
though bred together, when turned out, "in a short
time separate to a sheep ;" the Lincolnshh*es drawing
off to the rich soil, and the Norfolks to their own dry
light soil ; and as long as there is plenty of grass, " the
two breeds keep themselves as distinct as rooks and
pigeons." In this case different habits of life tend to
keep the races distinct. On one of the Faroe islands,
not more than half a mile in diameter, the half-wild
native black sheep are said not to have readily mixed
with the imported white sheep. It is a more curious
fact that the semi-monstrous ancon sheep of modern
origin " have been observed to keep together, separating
themselves from the rest of the flock, when put into
enclosures with other sheep." 6 With respect to fallow
deer, which live in a semi-domesticated condition, Mr.
Bennett 7 states that the dark and pale coloured herds,
which have long been kept together in the Forest of

4 Render, 'Saugethiere von Para- ii. p. 186. See Rev. L. Landt's 'De-
guay,' s. 886. scription of Faroe,' p. 66. For the ancon

5 See a memoir by MM. Lherbette sheep, see ' Phil. Transact.,' 1818, p. 90.
and De Quatrefages, in 'Bull. Soc. 7 White's 'Nat. Hist, of Selbourne,'
d'Acclimat.,' torn, viii., July, 1861, p. edited by Bennett, p. 39. With respect
312. to the origin of the dark-coloured deer,

8 For the Norfolk sheep, see Mar- see 'Some Account of English Deer

snail's ' Rural Economy of Norfolk,' vol. Parks,' by E. P. Shirley, Esq.

130 CAUSES WHICH. CHECK Chap. XVI.

Dean, in High Meadow Woods, and in the New Forest,
have never been known to mingle : the dark-coloured
deer, it may be added, are believed to have been first
brought by James I. from Norway, on account of their
greater hardiness. I imported from the island of Porto
Santo two of the feral rabbits, which differ, as described
in the fourth chapter, from common rabbits; both proved
to be males, and, though they lived during some years
in the Zoological Gardens, the superintendent, Mr. Bart-
lett, in vain endeavoured to make them breed with
various tame kinds ; but whether this refusal to breed
was due to any change in instinct, or simply to their
extreme wildness ; or whether confinement had rendered
them sterile, as often occurs, cannot be told.

Whilst matching for the sake of experiment many of
the most distinct breeds of pigeons, it frequently ap-
peared to me that the birds, though faithful to their mar-
riage vow, retained some desire after their own kind.
Accordingly I asked Mr. Wicking, who has kept a larger
stock of various breeds together than any man in Eng-
land, whether he thought that they would prefer pairing
with their own kind, supposing that there were males
and females enough of each; and he without hesitation
answered that he was convinced that this was the case.
It has often been noticed that the dovecot pigeon seems
to have an actual aversion towards the several fancy
breeds ;8 yet all have certainly sprung from a common
progenitor. The Rev. W. D. Fox informs me that his
flocks of white and common Chinese geese kept distinct.

These facts and statements, though some of them are
incapable of proof, resting only on the opinion of expe-
rienced observers, show that some domestic races are led
by different habits of life to keep to a certain extent sepa-
rate, and that others prefer coupling with their own kind,

* 'The Dovecote,' by the Rev. E. S. DLxon, p. 155; Bechstein, 'Naturgesch.
Deutsclilands,' Band iv., 1795, s. 17.

Chap. XVI. THE CROSSING OF VARIETIES. 131

in the same manner as species in a state of nature, though
in a much less degree.

With respect to sterility from the crossing of domestic races, I
know of no well-ascertained case with animals. This fact, Beeing the
great difference in structure between some breeds of pigeons, fowls,
pigs, dogs, &c, is extraordinary, in contrast with the sterility of
many closely allied natural species when crossed; but we shall
hereafter attempt to show that it is not so extraordinary as it at first
appears. And it may be well here to recall to mind that the amount
of external difference between two species*vrill not safely guide us
in foretelling whether or not they will breed together, — some close-
ly allied species when crossed being utterly sterile, and others
which are extremely unlike being- moderately fertile. I have said
that no case of sterility in crossed races rests on satisfactory evi-
dence ; but here is one which at first seems trustworthy. Mr.
Touatt,9 and a better authority cannot be quoted, states, that former-
ly in Lancashire crosses were frequently made between longhorn
and shorthorn cattle ; the first cross was excellent, but the produce
was uncertain ; in the third or fourth generation the cows were bad
milkers ; " in addition to which, there was much uncertainty whether
the cows would conceive ; and full one-third of the cows among
some of these half-breds failed to be in calf." This at first seems a
good case; but Mr. Wilkinson states,10 that a breed derived from
this same cross was actually established in another part of England ;
and if it had failed in fertility, the fact would surely have been no-
ticed. Moreover, supposing' that Mr. Touatt had proved his case,
it might be argued that the sterility was wholly due to the two pa-
rent-breeds being descended from primordially distinct species.

I will give a case with plants, to show how difficult it is to get
sufficient evidence. Mr. Sheriff, who has been so successful in the
formation of new races of wheat, fertilised the Hopetoun with the
Talavera ; in the first and second generations the produce was inter-
mediate in character, but in the fourth generation " it was found to
consist of many varieties ; nine-tenths of the florets proved barren,
and many of the seeds seemed shrivelled abortions, void of vitality,
and the whole race was evidently verging- to extinction." " Now,
considering how little these varieties of wheat differ in any im-
portant character, it seems to me very improbable that the sterility
resulted, as Mr. Sheriff thought, from the cross, but from some quite

» ' Cattle,' p. 202. dressed to Sir J. Sebright,' 1820, p. 88.

11 Mr. J. Wilkinson, in' Remarks ad- " ' Gardener's Chronicle,' I<n~s, p. 771.

132 CAUSES WHICH CHECK Chap. XVI.

distinct cause. Until such experiments are many times repeated,
it would be rash to trust them ; but unfortunately they have been
rarely tried even once with sufficient care.

Gartner has recorded a more remarkable and trustworthy case :
he fertilised thirteen panicles (and subsequently nine others) on a
dwarf maize bearing yellow seed a2 with pollen of a tall maize hav-
ing red seed ; and one head alone produced good seed, only five in
number. Though these plants are monoecious, and therefore do
not require castration, yet I should have suspected some accident
in the manipulation had not Gartner expressly stated that he had
during many years grown these two varieties together, and they
did not spontaneously cros3 ; and this, considering that the plants
are monoecious and abound with pollen, and are well known gener-
ally to cross freely, seems explicable only on the belief that these
two varieties are .in some degree mutually infertile. The hybrid
plants raised from the above five seed were intermediate in struc-
ture, extremely variable, and perfectly fertile.13 No one, I believe,
has hitherto suspected that these varieties of maize are distinct spe-
cies ; but had the hybrids been in the least sterile, no doubt Gartner
would at once have so classed them. I may here remark, that with
undoubted species there is not necessarily any close relation between
the sterility of a first cross and that of the hybrid offspring. Some
species can be crossed with facility, but produce utterly sterile hy-
brids ; others can be crossed with extreme difficulty, but the hybrids
when produced are moderately fertile. I am not aware, however, of
any instance quite like this of the maize with natural species, namely,
of a first cross made with difficulty, but yielding perfectly fertile hy-
brids.

The following case is much more remarkable, and evidently per-
plexed Gartner, whose strong wish it was to draw a broad line of
distinction between species and varieties. In the genus Verbascum,
he made, during eighteen years, a vast number of experiments, and
crossed no less than 1085 flowers and counted their seeds. Many of
these experiments consisted in crossing white and yellow Ararieties
of both V. lychnitis and V. blattaria with nine other species and
their hybrids. That the white and yellow flowered plants of these
two species are really varieties, no one has doubted ; and Gartner
actually raised in the case of both species one variety from the seed
of the other. Now in two of his works 14 he distinctly asserts that
crosses between similarly-coloured flowers yield more seed than be-

12 ' Bastarderzeugung,' s. 87, 169. See 14 'KenntnissderBefruchtung,'s. 137;
also the Table at the end of volume. ' Bastarderzeugung,' s. 92, 181. On raising

13 ' Bastarderzeugung,' s, 87, 577. the two varieties from seed see s. 307.

Chap. XVI. THE CROSSING OF VARIETIES. 133

tween dissimilarly-coloured ; so that the yellow-flowered variety of
either Bpocies (and conversely with the white-flowered variety),
when crossed with pollen of its own kind, yields more seed than
when crossed with that of the white variety; and so it is when
differently coloured species are crossed. The general results may
be seen in the Table at the end of his volume. In one instance he
gives ia the following details ; but I must premise that Gartner, to
avoid exaggerating the degree of sterility in his crosses, always
compares the maximum number obtained from a cross with the
average number naturally given by the pure mother-plant. The
white variety of V. lychnitis, naturally fertilised by its own pollen,
gave from an average of twelve capsules ninety-six good seeds in
each ; whilst twenty flowers fertilised with pollen from the yellow
variety of this same species, gave as the maximum only eighty-nine
good seed ; so that we have the proportion of 1000 to 908, according
to Gartner's usual scale. I should have thought it possible that so
small a difference in fertility might have been accounted for by the
evil effects of the necessary castration ; but Gartner shows that the
white variety of V. lychnitis, when fertilised first by the white va-
riety of V. blattaria, and then by the yellow variety of this species,
yielded seed in the proportion of 622 to 438 ; and in both these cases
( astration was performed. Now the sterility which results from the
crossing of the differently coloured varieties of the same species, is
fully as great as that which occurs in many cases when distinct
species are crossed. Unfortunately Gartner compared the results
of the first unions alone, and not the sterility of the two sets of
hybrids produced from the white variety of V. lychnitis when ferti-
lised by the white and yellow varieties of V. blattaria, for it is pro-
bable that they would have differed in this respect.

Mr. J. Scott -has given me the results of a series of experiments
on Verbascum, made by him in the Botanic Gardens of Edinburgh.
He repeated some of Gartner's experiments on distinct species, but
obtained only fluctuating results ; some confirmatory, but the greater
number contradictory ; nevertheless these seem hardly sufficient to
overthrow the conclusions arrived at by Gartner from experiments
tried on a much larger scale. In the second place Mr. Scott experi-
mented on the relative fertility of unions between similarly and
dissimilarly-coloured varieties of the same species. Thus he fer-
tilised six flowers of the yellow variety of V. lychnitis by its own
pollen, and obtained six capsules, and calling, for the sake of hav-
ing a standard of comparison, the average number of good seed in
each one hundred, he found that this same yellow variety, when

is ' Bastarderzeugung,' s. 21G.

134 CAUSES WHICH CHECK Chap. XVI.

fertilised by the white variety, yielded from seven capsules an
average of ninety-four seed. On the same principle, the white
variety of V. lychnitis by its own pollen (from six capsules), and
by the pollen of the yellow variety (eight capsules), yielded seed
in the proportion of 100 to 82. The yellow variety of V. thapsus
by its own pollen (eight capsules), and by that of the white variety
(only two capsules), yielded seed in the proportion of 100 to 94.
Lastly, the white variety of V. blattaria by its own pollen (eight
capsules), and by that of the yellow variety (five capsules), yielded
seed in the proportion of 100 to 79. So that in every case the uni-
ons of dissimilarly-coloured varieties of the same species were less
fertile than the unions of similarly-coloured varieties ; when all the
cases are grouped together, the difference of fertility is as 86 to 100.
Some additional trials were made, and altogether thirty-six simi-
larly-coloured unious yielded thirty-five good capsules ; whilst thir-
ty-five dissimilarly-coloured unions yielded only twenty-six good
capsules. Besides the foregoing experiments, the purple V. phas-
niceum was crossed by a rose-coloured and j, white variety of the
same species ; these two varieties were also crossed together, and
these several \inions yielded less seed than V. pheeniceum by its
own pollen. Hence it follows from Mr. Scott's experiments, that
in the genus Verbascum the similarly and dissimilarly-coloured
varieties of the same species behave, when crossed, like closely
allied but distinct species.16

This remarkable fact of the sexual affinity of similarly-coloured
varieties, as observed by Gartner and Mr. Scott, may not be of very
rare occurrence ; for the subject has not been attended to by others.

]0 The following facts, given by K61- have a stronger elective affinity for the

renter in his ' Dritte Fortsetzung,' s. 84, pollen of their own variety than for that

39, appear at first sight strongly to con- of the other ; this elective affinity, I may

firm Mr. Scott's and Gartner'8 state- add, of each species for its own pollen

ments ; and to a certain limited extent (Kolreuter, ' Dritte Forts.,' s. 39, and

they do so. Kolreuter asserts, from in- Gartner, ' Bastarderz.,' passim) being

numerable observations, that insects in- a perfectly well-ascertained power. But

cessantly carry pollen from one species the force of the foregoing facts is much

and variety of Verbascum to another ; lessened by Gartner's numerous experi-

and I can confirm this assertion ; yet ments, for, differently from Kolreuter,

lie found that the white and yellow va- he never once got (' Bastarderz.,' s. 307)

rieties of Verbascum lychnitis often grew an intermediate tint when he crossed the

wild mingled together : moreover, he cul- yellow and white flowered varieties of

tivated these two varieties in considerable Verbascum. So that the fact of the white

numbers during four years in his garden, and yellow varieties keeping true to their

and they kept true by seed ; but when he colour by seed does not prove that they

crossed them, they produced flowers of an were not mutually fertilised by the pol-

intermediate tint. Hence it might have len carried by insects from one to the

been thought that both varieties must other.

Our. XVI. THE CROSSING OF VARIETIES loO

The following case is worth giving, partly to show how difficult it
is to avoid error. Dr. Herbert I7 has remarked that variously-
coloured double varieties of the hollyhock {Althmi rosea) may be
raised with certainty by seed from plants growing close together.
I have been informed that nurserymen who raise seed for sale do
not separate their plants ; accordingly I procured seed of eighteen
named varieties ; of these, eleven varieties produced sixty-two plants
all perfectly true to their kind ; and seven produced forty-nine
plants, half of which were true and half false. Mr. Masters of Can-
terbury has given me a more striking case ; he saved seed from a
great bed of twenty-four named varieties planted in closely adjoin-
ing rows, and each variety reproduced itself truly with only some-
times a shade of difference in tint. Now in the hollyhock the pol-
len, which is abundant, is matured and nearly all shed before the
stigma of the same flower is ready to receive it ; 18 and as bees cov-
ered with pollen incessantly fly from plant to plant, it would ap-
pear that adjoining varieties could not escape being crossed. As,
however, this does not occur, it appeared to me probable that the
pollen of each variety was prepotent on its own stigma over that of
all other varieties. But Mr. C. Turner of Slough, well known for
his success in the cultivation of this plant, informs me that it is the
doubleness of the flowers which prevents the bees gaining access to
the pollen and stigma ; and he finds that is difficult even to cross
them artificially. Whether this explanation will fully account for
varieties in close proximity propagating themselves so truly by
seed, I do not know.

The following cases are worth giving, as they relate to monoe-
cious forms, which do not require, and consequently have not been
injured by, castration. Girou de Buzareingues crossed what he
designates three varieties of gourd,19 and asserts that their mutual
fertilisation is less easy in proportion to the difference which they
present. I am aware how imperfectly the forms in this group were
until recently known ; but Sageret,20 who ranked them according
to their mutual fertility, considers the three forms above alluded to
as varieties, as does a far higher authority, namely, M. Naudin.21
Sageret as has observed that certain melons have a greater tendency,

>T ' Araaryllidaceas,' 1S37, p. 366. xxx., 1833, pp. 398 and 405.

Gartner has made a similar observation. 20 ' Memoire sur les Cucurbitacete,'

18 Kolreuter first observed this fact. 1826, pp. 4C, 55.

'Mem. de l'Acad. St. Petersburg,' vol. 21 ' Annales des Sc. Nat.,' 4th series,

iii. p. 197. See also C. K. Sprengel, ■ Das torn. vi. M. Naudin considers these

Entdeekte Geheimniss,' s. 345. forms as undoubtedly varieties of Cu-

19 Namely, Barbarines, Pastissons, curiitapepO.
Glraumbus : ' Annal. des Sc. Nat.,1 torn. ss 'Mem. Cacui'b.,' p. 9.

136 CROSSING OF VARIETIES. Chap. XVI.

whatever the cause may be, to keep true than others ; and M.
Naudin, who has had such immense experience in this group, informs
me that he believes that certain varieties intercross more readily
than others of the same species ; but he has not proved the truth of
this conclusion ; the frequent abortion of the pollen near Paris being
one great difficulty. Nevertheless, he has grown close together,
during seven years, certain forms of Citrullus, which, as they could
be artificially crossed with perfect facility and produced fertile off-
spring, are ranked as varieties ; but these forms when not artifi-
cially crossed kept true. Many other varieties, on the other hand,
in the same group cross with such facility, as M. Naudin repeatedly
insists, that without being grown far apart they cannot be kept in
the least true.

Another case, though somewhat different, may be here given, as
it is highly remarkable, and is established on excellent evidence.
Kolreuter minutely describes five varieties of the common tobacco,23
which were reciprocally crossed, and the offspring were intermedi-
ate in character and as fertile as their parents : from this fact Kol-
reuter inferred that they are really varieties ; and no one, as far as I
can discover, seems to have doubted that such is the case. He also
crossed reciprocally these five varieties with iV. glutinosa, and they
yielded very sterile hybrids ; but those raised from the var. perennis,
whether used as the father or mother plant, were not so sterile as
the hybrids from the four other varieties.24 So that the sexual ca-
pacity of this one variety has certainly been in some degree modi-
fied, so as to approach in nature that of Zf. glutinosa™

23 ' Zweite Forts.,' s. 53, namely, Ni- after the one and some after the other
cotiana major vulgaris ; (2) perennis ; parent.

(3) Transylvanica ; (4) a sub- var. of the 2S Mr. Scott has made some observa-

last ; (5) major latifol. fl. alb. tions on the absolute sterility of a purple

24 Kolreuter was so much struck with and white primrose (Primula vulgaris)
this fact that he suspected that a little when fertilised by pollen from the com-
pollen of JV". glutinosa in one of his ex- mon primrose (' Journal of Proc. of Linn,
periments might, have accidentally got Soc.,' vol. viii., 1S64, p. 9S) ; but these
mingled with that of var. perennis, and observations require confirmation. I
thus aided its fertilizing power. But we raised a number of purple-flowered long-
now know conclusively from Gartner styled seedlings from seed kindly sent
(' Bastarderz.,' s. 34, 43) that two kinds of me by Mr. Scott, and, though they were
pollen never act conjointly on a third all in some degree sterile, they were
species ; still less will the pollen of a dis- much more fertile with pollen taken from
tinct species, mingled with a plant's own the common primrose than with their
pollen, if the latter be present in suffi- own pollen. Mr. Scott has likewise de-
cient quantity, have any effect. The 6cribed a red equal-styled cowslip
sole effect of mingling two kinds of pol- (P. veris, idem, p. 106), which was
len is to produce in the same capsule found by him to be highly sterile when
seeds which yield plants, some taking crossed with the common cowslip ; bat

Chap. xvi. DOMESTICATION ELIMINATES STEKLLITY. 137

These facts with respect to plants show that in some
few cases certain varieties have had their sexual powers
so far moilitied, that they cross together less readily and
yield less seed than other varieties of the same species.
We shall presently see that the sexual functions of most
animals and plants are eminently liable to be affected by
the conditions of life to which they are exposed ; and
hereafter we shall briefly discuss the conjoint bearing of
this and other facts on the difference in fertility between
crossed varieties and crossed species.

Domestication eliminate? the tendency to Sterility which
is general tcith Sjiecies when crossed.

This hypothesis was first propounded by Pallas,26 and
has been adopted by several authors. I can find hardly
any direct facts in its support ; but unfortunately no one
has compared, in the case of either animals or plants, the
fertility of anciently domesticated varieties, when crossed
with a distinct species, with that of the wild parent-spe-
cie's when similarly crossed. No one has compared, for
instance, the fertility of G alias banJciva and of the domes-
ticated fowl, when. crossed with a distinct species of Gal-
lus or Phasianus ; and the experiment would in all cases
be surrounded by many difficulties. Dureau de la Malle,
who has so closely studied classical literature, states27
that in the time of the Romans the common mule was
produced with more difficulty than at the present day ;
but whether this statement may be trusted I know not.
A much more important, though somewhat different, case

this was not the case with several equal- anomaly of the two forms combined in

styled red seedlings raised by me from the same flower. Hence it is not sur-

his plant. This variety of the cowslip prising that these flowers should be spon-

presents the remarkable peculiarity of taneously self-fertile in a high degree,

combining male organs in every respect 26 ' Act. Acad. St. Petersburg,' 17*0,

like those of the short-styled form, with part ii., pp. 84, 100.

female organs resembling in function 27 ' Annales des Sc. Nat.,' torn. xxi.

ami partly in structure those of the long- (1st series), p. 01.
styled form ; so that we have the singular

138 DOMESTICATION ELIMINATES STERILITY. Chap. XVI.

is given by M. Groenland,28 namely, that plants, known
from their intermediate character and sterility to be hy-
brids between iEgilops and wheat, have perpetuated
themselves under culture since 1857, with a rapid but
varying increase of fertility in each generation. In the
fourth generation the plants, still retaining their interme-
diate character, had become as fertile as common culti-
vated wheat.

The indirect evidence in favour of the Pallasian doc-
trine appears to me to be extremely strong. In the ear-
lier chapters I have attempted to show that our various
breeds of dogs are descended from several wild species ;
and this probably is the case with sheep. There can no
longer be any doubt that the Zebu or humped Indian ox
belongs to a distinct species from European cattle : the
latter, moreover, are descended from two or three forms,
which may be called either species or wild races, but
which co-existed in a state of nature and kept distinct.
We have good evidence that our domesticated pigs be-
long to at least two specific types, S. scrofa and Tndica,
which probably lived together in a wild state in South-
eastern Europe. Now, a widely-extended analogy leads
to the belief that if these several allied species, in the
wild state or when first reclaimed, had been crossed, they
would have exhibited, both in their first unions and in
their hybrid offspring, some degree of sterility. Never-
theless the several domesticated races descended from
them are now all, as far as can be ascertained, perfectly
fertile together. If this reasoning be trustworthy, and
it is apparently sound, we must admit the Pallasian doc-
trine that long-continued domestication tends to elimin-
ate that sterility which is natural to species when crossed
in their aboriginal state.

a8 'Bull. Bot. Soc. de France,' Dec. 27th, 1861, torn. viii. p. 612.

Chap. XVI. INCREASED FERTILITY. 139

On Increased Fertility from Domestication and Culti-
vation.

Increased fertility from domestication, without any
reference to crossing, may be here briefly considered.
This subject bears indirectly on two or three points con-
nected with the modification of organic beings. As Buf-
fon long ago remarked,29 domestic animals breed oftener
in the year and produce more young at a birth than wild
animals of the same species ; they, also, sometimes breed
at an earlier age. The case would hardly have deserved
further notice, had not some authors lately attempted to
show that fertility increases and decreases in an inverse
ratio with the amount of food. This strange doctrine
has apparently arisen from individual animals when sup-
plied with an inordinate quantity of food, and from plants
of many kinds when grown on excessively rich soil, as
on a dunghill, becoming sterile ; but to this latter point
I shall have occasion presently to return. With hardly
an exception, our domesticated animals, which have long
been habituated to a regular and copious supply of food,
without the labour of searching for it, are more fertile
than the corresponding wild animals. It is notorious how
frequently cats and dogs breed, and how many young
they produce at a birth. The wild rabbit is said gener-
ally to breed four times yearly, and to produce from
four to eight young ; the tame rabbit breeds six or seven
times yearly, and produces from four to eleven young.
The ferret, though generally so closely confined, is more
prolific than its supposed wild prototype. The wild
sow is remarkably prolific, for she often breeds twice in
the year, and produces from four to eight and sometimes
even twelve young at a birth ; but the domestic sow

39 Quoted by Isid. Oeoffroy St. nilaire, subject has appeared in Mr. Herbert

' nist. Naturelle Generate,' torn. iii. p. Spencer's ' Principles of Biology,' vol. ii.

476. Since this MS. has been sent to 1S67, p. 457 e£ seq*
press a full discussion on the present

140 INCREASED FERTILITY Chap. XVL

regularly breeds twice a year, and would breed oftener
if permitted; and a sow that produces less than eight
at a birth " is worth little, and the sooner she is fattened
for the butcher the better." The amount of food aifects
the fertility even of the same individual : thus sheep,
which on mountains never produce more than one lamb
at a birth, when brought down to lowland pastures fre-
quently bear twins. This difference apparently is not
due to the cold of the higher land, for sheep and other
domestic animals are said to be extremely prolific in Lap-
land. Hard living, also, retards the period at which
animals conceive ; for it has been found disadvantageous
in the northern islands of Scotland to allow cows to bear
calves before they are four years old.30

Birds offer still better evidence of increased fertility from domes-
tication : the lien of the wild Gallus bankiva lays from six to ten
eggs, a number which would be thought nothing of with the do-
mestic hen. The wild duck lays from five to ten eggs ; the tame
one. in the course of the year from eighty to one hundred. The
wild grey-lag goose lays from five to eight eggs ; the tame from
thirteen to eighteen, and she lays a second time ; as Mr. Dixon has
remarked, " high-feeding, care, and moderate warmth induce a habit
of prolificacy which becomes in some measure hereditary." Whether
the semi-domesticated dovecot pigeon is more fertile than the wild
rock pigeon, G. lima, I know not ; but the more thoroughly domes-
ticated breeds are nearly twice as fertile as dovecots ; the latter,
however, when caged and highly fed, become equally fertile with
house pigeons. The peahen alone of domesticated birds is rather
more fertile, according to some accounts, when wild in its native
Indian home, than when domesticated in Europe and exposed to our
much colder climate.31

30 For cats and dogs, &c, see Bellin- s. 534; for the domestic pig, Sidney's
geri, in ' Annal. des Sc. Nat.,' 2nd series, edit, of Youatt on the Pig, 1S60, p. 62.
Zoolog., torn. xii. p. 155. For ferrets, With respect to Lapland, see Aoerbi's
Bechstein, ' Naturgeschichte Deutsch- ' Travels to the North Cape,' Eng. trans-
lands,' Band i., 1801, s. 786, 795. For lat., vol. ii. p. 222. About the Highland
rabbits, ditto, s. 1123, 1131 ; and Bronn's cows, see Hogg on Sheep, p. 263.
' Geschichte der Natur,' B. ii. s. 99. For Sl For the eggs of Gallus bankiva, see
mountain sheep, ditto, s. 102. For the Blyth, in 'Annals and Mag. of Nat
fertility of the wild sow, sec Bechstein's Hist.,' 2nd series, vol. i. 1848, p. 456.
' Naturgesch. Deutschlands,'' B. i., 1801, For wild and tame ducks, Macgillivray,

Chap. XVI. FROM DOMESTICATION. 141

With respect to plants, no one would expect wheat to tiller more,
and each ear to produce more grain, in poor than "in rich soil ; or to
get in poor soil a heavy crop of peas or beans. Seeds vary so much
in number that it is difficult to estimate them ; but on comparing
beds of carrots saved for seed in a nursery garden with wild plants,
the former seemed to produce about twice as much seed. Cultivated
cabbages yielded thrice as many pods by measure as wild cabbages
from the rocks of South Wales. The excess of berries produced by
the cultivated Asparagus in comparison with the wild plant is
enormous. No doubt many highly cultivated plants, such as pears,
pineapples, bananas, sugar-cane, &c, are nearly or quite sterile ; and
I am inclined to attribute this sterility to excess of food and to
other unnatural conditions; but to this subject ■ I shall presently
recur. ■

In some cases, as with the pig, rabbit, &c, and with
those plants which are valued for their seed, the direct
selection of the more fertile individuals has probably-
much increased their fertility ; and in all cases this may
have occurred indirectly, from the better chance of the
more numerous offspring produced by the more fertile
individuals having survived. But with cats, ferrets, and
dogs, and with plants like carrots, cabbages, and aspara-
gus, which are not Aralued for their prolificacy, selection
can have played only a subordinate part ; and their in-
creased fertility must be attributed to the more favoura-
ble conditions of life under which they have long existed.

'British Birds,' vol. v. p. 37; and 'Die geons,' &c, 1S13, torn. ii. p. 41), the hen

Enten,' s. 87. For wild geese, L. Lloyd, lays in India even as many as twenty

' Scandinavian Adventures,' vol. ii. 1S54, eggs ; but according to Jerdon and an-

p. 413; and for tame geese, 'Ornamental other writer (quoted in Tegetmeier's

Poultry,' by Rev. E. S. Dixon, p. 139. 'Poultry Book,' 1S66, pp. 2S0, 2S2), she

On the breeding of pigeons, Pistor, ' Das there lays only from four to nine or ten

Gauze derTaubenzucht,'ls31,s. 46; and eggs: in England she is said, in the

Boitard and Corbie, ' Les Pigeons,' p. 15S. 'Poultry Book,' to lay five or six, but

With respect to peacocks, according to another writer says from eight to twelve

Temminck (' Hist. Nat. Gen. des Pi- eggs.

142 GOOD FROM CROSSING. Chap. XVIL

CHAPTER XVIL

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

•

DEFINITION OF CLOSE INTERBREEDING — AUGMENTATION OF MOR-
BID TENDENCIES — GENERAL EVIDENCE ON THE GOOD EFFECTS
DERIVED FROM CROSSING, AND ON THE EVIL EFFECTS FROM
CLOSE INTERBREEDLNG — CATTLE, CLOSELY INTERBRED; HALF-
WILD CATTLE LONG KEPT IN THE SAME PARKS — SHEEP — FAL-
LOW-DEER— DOGS — RABBITS — PIGS — MAN, ORIGIN OF HIS AB-
HORRENCE OF INCESTUOUS MARRIAGES — FOWLS — PIGEONS —
HIVE-BEES — PLANTS, GENERAL CONSIDERATIONS ON THE BENE-
FITS DERIVED FROM CROSSING — MELONS, FRUIT-TREES, PEAS,
CABBAGES, WHEAT, AND FOREST-TREES — ON THE INCREASED
SIZE OF HYBRID PLANTS, NOT EXCLUSIVELY DUE TO THEIR STE-
RILITY— ON CERTAIN PLANTS WHICH EITHER NORMALLY OR AB-
NORMALLY ARE SELF-IMPOTENT, BUT ARE FERTILE, BOTH ON
THE MALE AND FEMALE SIDE, WHEN CROSSED WITH DISTINCT
INDIVIlfCALS EITHER OF THE SAME OR ANOTHER SPECIES —
CONCLUSION.

The gain in constitutional vigor, derived from an occa-
sional cross between individuals of the same variety, but
belonging to distinct families, or between distinct varie-
ties, has not been so largely or so frequently discussed,
as have the evil effects of too close interbreeding. But
the former point is the more important of the two, inas-
much as the evidence is more decisive. The evil results
from close interbreeding are difficult to detect, for they
accumulate slowly, and differ much in degree with dif-
ferent species ; whilst the good effects which almost in-
variably follow a cross are from the first manifest. It

Chap. XVII. EVIL FROM INTERBREEDING. 143

should, however, be clearly understood that the advan-
tage of close interbreeding, as far as the retention of
character is concerned, is indisputable, and often out-
weighs the evil of a slight loss of constitutional vigour.
In relation to the subject of domestication, the whole
question is of some importance, as too close interbreed-
ing interferes with the improvement of old races, and
especially with the formation of new ones. It is im-
portant as indirectly bearing on Hybridism ; and per-
haps on the extinction of species, when any form has be-
come so rare that only a few individuals remain within a
confined area. It bears in an important manner on the
influence of free intercrossing, in obliterating individual
differences, and thus giving uniformity of character to
the individuals of the same race or species ; for if addi-
tional vigour and fertility be thus gained, the crossed
offspring will multiply and prevail, and the ultimate re-
sult will be far greater than otherwise would have occur-
red. Lastly, the question is of high interest, as bearing
on mankind. Hence I shall discuss this subject at full
length. As the facts which prove the evil effects of close
interbreeding are more copious, though less decisive,
than those on the good effects of crossing, I shall, under
each group of beings, begin with the former.

There is no difficulty in defining what is meant by a
cross ; but this is by no means easy in regard to " breed-
ing in and in" or "too close interbreeding," because, as
we shall see, different species of animals are differently
affected by the same degree of interbreeding. The
pairing of a father and daughter, or mother and son, or
brothers and sisters, if carried on during several gen-
erations, is the closest possible form of interbreeding.
But some good judges, for instance Sir J. Sebright,
believe that the pairing of a brother and sister is closer
than that of parents and children ; for when the father is
matched with his daughter he crosses, as is said, with
only half his own blood. The consequences of close

144 GOOD FROM CROSSING. Chap. XVIL

interbreeding carried on for too long a time, are, as is
generally believed, loss of size, constitutional vigour,
and fertility, sometimes accompanied by a tendency to
malformation. Manifest evil does not usually follow
from pairing the nearest relations for two, three, or even
four generations ; but several causes interfere with our
detecting the evil — such as the deterioration being very
gradual, and the difficulty of distinguishing between such
direct evil and the inevitable augmentation of any morbid
tendencies which may be latent or apparent in the related
parents. On the other hand, the benefit from a cross
even when there has not been any very close interbreed-
ing, is almost invariably at once conspicuous. There is
reason to believe, and this was the ojiinion of that most
experienced observer Sir J. Sebright,1 that the evil effects
of close interbreeding may be checked by the related
individuals being separated during a few generations and
exposed to different conditions of life.

That evil directly follows from any degree of close
interbreeding has been denied by many persons; but
rarely by any practical breeder ; and never, as far as I
know, by one who has largely bred animals which pro-
pagate their kind, quickly. Many physiologists attribute
the evil exclusively to the combination and consequent
increase of morbid tendencies common to both parents :
that this is an active source of mischief there can be no
doubt. It is unfortunately too notorious that men and
various domestic animals endowed with a wretched con-
stitution, and with a strong hereditary disposition to
disease, if not actually ill, are fully capable of procreating
their kind. Close interbreeding, on the other hand, in-
duces sterility ; and this indicates something quite dis-
tinct from the augmentation of morbid tendencies com-
mon to both parents. The evidence immediately to be
given convinces me that it is a great law of nature, that

» ' The Art of Improving the Breed, &c.,' 1S09, p. 16.

Chap. xvii. EVIL FROM INTERBREEDING. 145

all organic beings profit from an occasional cross with
individuals not closely related to them in blood ; ami
that, on the other hand, long-continued close interbreed-
ing is injurious.

Various general considerations have had much in-
fluence in leading me to this conclusion ; but the reader
Avill probably rely more on special facts and opinions.
The authority of experienced observers, even when they
do not advance the grounds of their belief, is of some
little value. Now almost all meu who have bred many
kinds of animals and have written on the subject, such as
Sir J. Sebright, Andrew Knight, &c.,2 have expressed
the strongest conviction on the impossibility of long-
continued close interbreeding. Those who have com-
piled works on agriculture, and have associated much
with breeders, such as the sagacious Youatt, Low, &c,
have strongly declared their opinion to the same effect.
Prosper Lucas, trusting largely to French authorities,
has come to a similar conclusion. The distinguished
German agriculturist Hermann von Nathusius, Avho has
written the most able treatise on this subject which I
have met with, concurs ; and as I shall have to quote
from this treatise, I may state that Nathusius is not only
intimately acquainted with works on agriculture in all
languages, and knows the pedigrees of our British breeds
better than most Englishmen, but has imported many of
our improved animals, and is himself an experienced
breeder.

Evidence of the evil effects of close interbreeding can
most readily be acquired in the case of animals, such as
fowls, pigeons, &c, which propagate quickly, and, from
being kept in the same place, are exposed to the same
conditions. Now I have inquired of very many breeders
of these birds, and I have hitherto not met with a single

4 For Andrew Knight, see A. Walker, on ' Intermarriage,' 1S3S, p. 227. Sir J.
Sebright';: Treatise has just been quoted.

146 GOOD FEOM CROSSING. Chap. XVII.

man who was not thoroughly convinced that an occasional
cross "with another strain of the same sub-variety was
absolutely necessary. Most breeders of highly-improved
or fancy birds value their own strain, and are most un-
willing, at the risk, in their opinion, of deterioration, to
make a cross. The purchase of a first-rate bird of an-
other strain is expensive, and exchanges are troublesome ;
yet all breeders, as far as I can hear, excepting those who
keep large stocks at different places for the sake of cross-
ing, are driven after a time to take this step.

Another general consideration which has had great in-
fluence on my mind is, that with all hermaphrodite ani-
mals and plants, which it might have been thought would
have perpetually fertilised themselves, and thus have
been subjected for long ages to the closest interbreeding,
there is no single species, as far as I can discover, in which
the structure ensures self-fertilisation. On the contrary,
there are in a multitude of cases, as briefly stated in the
fifteenth chapter, manifest adaptations which favour or
inevitably lead to an occasional cross between one her-
maphrodite and another of the same species ; and these
adaptive structures are utterly purposeless, as far as we
can see, for any other end.

With Cattle there can be no doubt that extremely close interbreed-
ing may be long carried on, advantageously with respect to external
characters and with no manifestly apparent evil as far as constitu-
tion is concerned. The same remark is applicable to sheep. Whether
these animals have gradually been rendered less susceptible than
others to this evil, in order to permit them to live in herds, — a habit
which leads the old and vigorous males to expel all intruders, and
in consequence often to pair with their own daughters, I will not
pretend to decide. The case of Bakewell's Longhorns, which were
closely interbred for a long period, has often been quoted ; yet
Youatt says 3 the breed " had acqiiired a delicacy of constitution in-
consistent with common management," and " tbe propagation of the
species was not always certain." But the Shorthorns offer the most

8 'Cattle,' p. 199,

Ohap. XVII. EVIL FROM INTERBREEDING. 147

striking case of close interbreeding ; for instance, the famous bull
Favourite (who was himself the offspring of a half brother and sister
from Foljambe) was matched with his own daughter, grand-
daughter, and great-granddaughter ; so that the produce of this last
union, or the great-great-granddaughter, had 15-16ths, or 9375 per
cent, of the blood of Favourite in her veins. This cow was matched
with the bull Wellington, having 625 per cent, of Favourite blood
in his veins, and produced Clarissa ; Clarissa was matched with the
bull Lancaster, having 6875 of the same blood, and she yielded
valuable offspring.4 Nevertheless Collings, who reared these ani-
mals, and was a strong advocate for close breeding, once crossed his
stock with a Galloway, and the cows from this cross realised the
highest prices. Bates's herd was esteemed the most celebrated in
the world. For thirteen years he bred most closely in and in ; but
during the next seventeen years, though he had the most exalted
notion of the value of his own stock, he thrice infused fresh blood
into his herd : it is said that he did this, not to improve the form of
his animals, but on account of their lessened fertility. Mr. Bates's
own view, as given by a celebrated breeder,5 was, that " to breed in
and in from a bad stock was nun and devastation ; yet that the
practice may be safely followed within certain limits when the pa-
rents so related are descended from first-rate animals." We thus
see that there has been extremely close interbreeding with Short-
horns ; but Xathusius, after the most careful study of their pedigrees,
says that he can find no instance of a breeder who has strictly
followed this practice during Ids whole life. From this study and
his own experience, he concludes that close interbreeding is ne-
cessary to ennoble the stock ; but that in effecting this the greatest
care is necessary, on account of the tendency to infertility and weak-
ness. It may be added, that another high authority 6 asserts that
many more calves are born cripples from Shorthorns than from
other and less closely interbred races of cattle.

Although by carefully selecting the best animals (as Nature ef-
fectually does by the law of battle) close interbreeding maybe long
carried on with cattle, yet the good effects of a cross between almost
any two breeds is at once shown by the greater size and vigour of

4 Xathusius, ' Ueber Shorthorn Rind- 6 Mr. Willoughhy Wood, in ' Gar-

vieh,' 1S57, s. 71 : see also ' Gardener's dener's Chronicle,' 1855, p. 411 ; and

Chronicle,' 1S60, p. 270. Many analo- 1S60, p. 270. See the very clear tables

gous cases are given in a pamphlet re- and pedigrees given in Nathusius'

cently published by Mr. C. Mac-knight ' Rindvieh,' s. 72-77.

and Dr. II. Madden, ' On the True 6 Mr. Wright, ' Journal of Royal

Principles of Breeding ; ' Melbourne, Agricult. Soc..' vol. vii., 1S4G, p. 204.
Australia, 18G5.

148 GOOD FROM CROSSING. Chap. XVII.

the offspring ; as Mr. Spooner writes to me, " crossing distinct breeds
certainly improves cattle for the butcher." Such crossed animals
are of course of no value to the breeder : but they have been raised
during many years in several parts of England to be slaughtered ; 7
and their merit is now so fully recognised, that at fat-cattle shows
a separate class has been formed for their reception. The best fat
ox at the great show at Islington in 1862 was a crossed animal.

The half-wild cattle which have been kept in British parks prob-
ably for 400 or 500 years, or even for a longer period, have been ad-
vanced by Culley and others as a case of long-continued interbreed-
ing within the limits of the same herd without any consequent
injury. With respect to the cattle at Chillingham, the late Lord
Tankerville owned that they were bad breeders.8 The agent, Mr.
Hardy, estimates (in a letter tome, dated May, 1861) that in the
herd of about fifty the average number annually slaughtered, killed
by fighting, and dying, is about ten, or one in five. As the herd is
kept up to nearly the same average number, the annual rate of
increase must be likewise about one in five. The bulls, I may add,
engage in furious battles, of which battles the present Lord Tanker-
ville has given me a graphic description, so that there will always
be rigorous selection of the most vigorous males. I procured in
1855 from Mr. D. Gardner, agent to the Duke of Hamilton, the fol-
lowing account of the wild cattle kept in the Duke's park in Lan-
arkshire, which is about 200 acres in extent. The number of cattle
varies from sixty-five to eighty ; and the number annually killed (I
presume by all causes) is from eight to ten ; so that the annual rate
of increase can hardly be more than one in six. Now in South
America, where the herds are half-wild, and therefore offer a nearly
fair standard of comparison, according to Azara the natural increase
of the cattle on an estancia is from one-third to one-fourth of the
total number, or one in between three and four : and this, no doubt,
applies exclusively to adult animals fit for consumption. Hence the
half-wild British cattle which have long interbred within the limits
of the same herd are relatively far less fertile. Although in an un-
enclosed country like Paraguay there must be some crossing between
the different herds, yet even there the inhabitants believe that the
occasional introduction of animals from distant localities is neces-
sary to prevent " degeneration in size and diminution of fertility." "
The decrease in size from ancient times in the Chillingham and
Hamilton cattle must have been prodigious, for Professor RUtimeyer

r Youatt on Cattle, p. 202. 9 Azara, ' Quarlrupedes du Paraguay,'

8 Report British Assoc, Zoolog. Sect., torn. ii. pp. 354, 368.
1S38.

Cuap. XVII EVIL FROM INTERBREEDING. 149

lias shown that they are almost certainly the descendants of the
gigantic Bos pHmigenius. No doubt this decrease in size may be

largely attributed to less favourable conditions of life ; yet animals
roaming over large parks, and fed during severe winters, can hardly
be considered as placed under very unfavourable conditions.

With Sheep there has often been long-continued interbreeding
within the limits of the same flock ; but whether the nearest rela-
tions have been matched so frequently as in the case of Shorthorn
cattle, I do not know. The Messrs. Brown during fifty years have
never infused fresh blood into their excellent flock of Leicesters.
Since 1810 Mr. Barford has acted on the same principle with the
Foscote flock. He asserts that half a century of experience has
convinced him that when two nearly related animals are quite
sound in constitution, in-and-in breeding does not induce degene-
racy ; but he adds that he " does not pride himself on breeding from
the nearest affinities." In France the Naz flock has been bred for
sixty years without the introduction of a single strange ram.10
Nevertheless, most great breeders of sheep have protested against
close interbreeding prolonged for too great a length of time.11 The
most celebrated of recent breeders, Jonas Webb, kept five separate
families to work on, thus " retaining the requisite distance of re-
lationship between the sexes." 1S

Although by the aid of careful selection the near interbreeding
of sheep may be long continued without any manifest evil, yet it
has often been the practice with farmers to cross distinct breeds to
obtain animals for the butcher, which plainly shows that good is
derived from this practice. Mr. Spooner sums up his excellent
Essay on Crossing by asserting that there is a direct pecuniary ad-
vantage in judicious cross-breeding, especially when the male is
larger than the female. A former celebrated breeder, Lord Somer-
ville, distinctly states that his half-breeds from Ryelands and Spanish
sheep were larger animals than either the pure Ryelands or pure
Spanish sheep.13

As some of our British parks are ancient, it occurred to me that
there must have been long-continued close interbreeding with the
fallow deer (Cervus da/ma) kept in them ; but on inquiry I find that

10 For the case of the Messrs. Brown, 1S Lord Somerville, ' Facts on Sheep
see 'Gard. Chronicle,' 1S55, p. 26. For and Husbandry,' p. 6. Mr. Spooner, in
the Foscote flock, 'Gard. Chron.,' 1S60, 'Journal of Royal Agricult. Soc. of Eng-
p. 416. For the Naz flock, ' Bull, de la land,' vol. xx., part ii. See also an ex-
Soc. d'Acclimat.,' I860, p. 477. cellent paper da the same subject in

11 Nantnusiu3, ' Rindvieh,' s. 65; 'Gard. Chronicle,' I860, p. 321, by Mr.
Youatt on Sheep, p. 495. . Charles Howard.

:a ' Gard. Chronicle,' 1861, p. 631.

150 GOOD FKOM CROSSING. Chap. XVII.

it is a common practice to infuse new blood by procuring bucks from
other parks. Mr. Sbirley, 14 who has carefully studied the man-
agement of deer, admits that in some parks there has been no ad-
mixture of foreign blood from a time beyond the memory of man.
But he concludes " that in the end the constant breeding in-and-in
" is sure to tell to "the disadvantage of the whole herd, though it
" may take a very long time to prove it; moreover, when we find,
" as is very constantly the case, that the introduction of fresh blood
" has been of the very greatest use to deer, both by improving their
" size and appearance, and particularly by being of service in re-
" moving the taint of ' rickback,' if not of other diseases, to which
" deer are sometimes subject when the blood has not been changed,
" there can, I think, be no doubt but that a judicious cross with a
" good stock is of the greatest consequence, and is indeed essential,
" sooner or later, to the prosperity of every well-ordered park."

Mr. Meynell's famous foxhounds have been adduced, as showing
that no ill effects follow from close interbreeding ; and Sir J.
Sebright ascertained from him that he frequently bred from father
and daughter, mother and son, and sometimes even from brothers
and sisters. Sir J. Sebright, however, declares,15 that by breeding
in-and-in, by which he means matching brothers and sisters, he has
actually seen strong spaniels become weak and diminutive lapdogs.
The Rev. W. D. Fox has communicated to me the case of a small
lot of bloodhounds, long kept in the same family, which had become
very bad breeders, and nearly all had a bony enlargement in the
tail. A single cross with a distinct strain of bloodhounds restored
their fertility, and drove away the tendency to malformation in the
tail. I have heard the particulars of another case with bloodhounds,
in which the female had to be held to the male. Considering how
rapid is the natural increase of the dog, it is difficult to understand
the high price of most highly improved breeds, which almost im-
plies long-continued close interbreeding, except on the belief that
this process lessens fertility and increases liability to distemper and
other diseases. A high authority, Mr. Scrope, attributes the rarity
and deterioration in size of the Scotch deerhound (the few individu-
als now existing throughout the country being all related) in large
part to close interbreeding.

With all highly-bred animals there is more or less difficulty in
getting them to procreate quickly, and all suffer much from delicacy
of constitution ; but I do not pretend that these effects ought to be

14 ' Some Account of English Deer &c, p. 13. With respect to Scotch deer-
Parks,' by Evelyn P. Shirley, 1867. hounds, «ee.Scrope's ' Art of Deer Stalk-

15 ' The Art of Improving the Breed,' ing,' pp. 350-353.

Chap. XVI]. EVIL FROM INTERBREEDING. 151

wholly att ributed to close interbreeding. A great j udge of rabbits16
says, " the long-eared does are often too highly bred or forced in
their youth to be of much value as breeders, often turning out bar-
ren or bad mothers." Again : " Very long-eared bucks will also
sometimes prove barren." These highly-bred rabbits often desert
their young, so that it is necessary to have nurse-rabbits.

With Pigs there is more unanimity amongst breeders on the evil
effects of close interbreeding than, perhaps, with any other large
animal. Mr. Druce, a great and successful breeder of the Improved
Oxfordshires (a crossed race), writes, " without a change of boars of
a different tribe, but of the same breed, constitution cannot be pre-
served." Mr. Fisher Hobbs, the raiser of the celebrated Improved •
Essex breed, divided Ins stock into three separate families, by which
means he maintained the breed for more than twenty years, " by
judicious selection from the three distinct families." 1T Lord Western
was the first importer of a Neapolitan boar and sow. " From this
pair he bred in-and-in, until the breed was in danger of becoming
extinct, a sure result (as Mr. Sidney remarks) of in-and-in breeding."
Lord Western then crossed his Neapolitan pigs with the. old Essex,
and made the first great step towards the Improved Essex breed.
Here is a more interesting case. Mr. J. Wright, well known as a
breeder, crossed 18 the same boar with the daughter, granddaughter,
and great-granddaughter, and so on for seven generations. The
result was, that in many instances the offspring failed to breed ; in
others they produced few that lived ; and of the latter many were
idiotic, without sense even to suck, and when attempting to move
could not walk straight. Now it deserves especial notice, that the
two last sows produced by this long course of interbreeding were
sent to other boars, and they bore several litters of healthy pigs.
The best sow in external appearance produced during the whole
seven generations was one in the last stage of descent ; but the lit-
ter consisted of this one sow. She would not breed to her sire, yet
bred at the first trial to a stranger in blood. So that, in Mr.
Wright's case, long-continued and extremely close interbreeding did
not affect the external form or merit of the young ; but with many
of them the general constitution and mental powers, and especially
the reproductive functions, were seriously affected.

Xathusius gives 19 an analogous and even more striking case : he
imported from England a pregnant sow of the large Yorkshire breed,

in 'Cottage Gardensr,' 1861, p. 327. 18 'Journal, Royal Agricult. Soo. of

17 Sidney's edit, of Youatt on the Pig,' England,' lSlfi, vol. vii. p. 205.

1860, p. SO; p. 33, quotation from Mr. ia ' L'eber Rindvieh,' &c, s. 78.

Druce ; p. 29, on Lord Western's case.

152 GOOD FROM CROSSING. Chap. XVII.

and bred the product closely in-and-in for three generations : the re-
sult was unfavourable, as the young were weak in constitution,
with impaired fertility. One of the latest sows, which he esteemed
a good animal, produced, when paired with her own uncle (who was
known to be productive with sows of other breeds), a litter of six,
and a second time a litter of only five weak young pigs. He then
paired this sow with a boar of a small black breed, which he had
likewise imported from England, and which boar, when matched
with sows of his own breed, produced from seven to nine young :
now, the sow of the large breed, which was so unproductive when
paired with her own uncle, yielded to the small black boar, in the
first litter twenty-one, and in the second litter eighteen young pigs ;
so that in one year she produced thirty-nine fine young animals !

As in the case of several other animals already mentioned, even
when no injury is perceptible from moderately close interbreeding,
yet, to quote the words of Mr. Coate, a most successful breeder (who
five times won the annual gold medal of the Smithfield Club Show
for the best pen of pigs), "Crosses answer well for profit to the
farmer, as you get more constitution and quicker growth ; but for
me, who sell a^reat number of pigs for breeding purposes, I find it
will not do, as it requires many years to get anything like purity of
blood again." "°

Before passing on to Birds, I ought to refer to man,
though I am unwilling to enter on this subject, as it is
surrounded by natural prejudices. It has moreover been
discussed by various authors under many points of view.21
Mr. Tylor ™ has shown that with widely different races,
in the most distant quarters of the world, marriages be-
tween relations — even between distant relations — have
been strictly prohibited. A few exceptional cases can be
specified, especially with royal families ; and these have
been enlarged on in a learned article 23 by Mr. W. Adam,

20 Sidney on the Pig, p. 36. See also Manages,' &c, 1862, p. 141) that the
note, p. 34. Also Richardson on the Pig, marriages of cousins have been prohibit-
1847, p. 26. ed by the legislature of Ohio ; but I have

21 Dr. Dally has published an excel- been assured, in answer to inquiries
lent article (translated in the ' Anthro- made in the United States, that this state-
polog. Review,' May, 1864, p. 65), criti- ment is a mere fable.

cising all writers who have maintained 22 See his most interesting work on the

that evil follows from consanguineous 'Early History of Man,' 1S65, chap. x.

marriages. No doubt on this side of the 23 On Consanguinity in Marriage, in

question many advocates have injured the ' Fortnightly Review,' 1S65, p. 710;

their cause by inaccuracies : thus it has Hofacker, ' Ueber die Eigenschaften,' &c.
been stated (Devay, ' Du Danger des

Chap. XVII. EVIL FROM INTERBREEDING. 153

.and formerly in 1 828 by Ilofacker. Mr. Tylor is inclined
to believe that the almost universal prohibition of closely-
related marriages has arisen from their evil effects having
been observed, and he ingeniously explains some appa-
rent anomalies in the prohibition not extending equally to
the relations on both the male and female side. He ad-
mits, however, that other causes, such as the extension
of friendly alliances, may have come into play. Mr. TV.
Adam, on the other hand, concludes that related mar-
riages are prohibited and vieAved with repugnance from
the confusion which would thus arise in the descent of
property, and from other still more recondite reasons ;
but I cannot accept this view, seeing that the savages ot
Australia and South America,24 who have no property to
bequeath or fine moral feelings to confuse, hold the crime
of incest in abhorrence.

It would be interesting to know, if it could be ascer-
tained, as throwing light on this question with respect
to man, what occurs with the higher anthropomorphous
apes— whether the young males and females soon wander
away from their parents, or whether the old males be-
come jealous of their sons and expel them, or whether
any inherited instinctive feeling, from being beneficial,
has been generated, leading the young males and females
of the same family to prefer pairing with distinct families,
and to dislike pairing with each other. A considerable
body of evidence has already been advanced, showing
that the offspring from parents which are not related are
more vigorous and fertile than those from parents which
are closely related ; hence any slight feeling, arising from
the sexual excitement of novelty or other cause, which
led to the former rather than to the latter unions, would
be augmented through natural selection, and thus might
become instinctive ; for those individuals which had an

** Sir G. Grey's ' Journal of Expedi- Dobrizhoffer, ' On the Abipones of South
lions into Australia,' vol. ii. p. 243 ; and America.'

154 GOOD FKOM CROSSING. Chap. XVII.

innate preference of this kind would increase in number.
It seems more probable, that degraded savages should
thus unconsciously have acquired their dislike and even
abhorrence of incestuous marriages, rather than that they
should have discovered by reasoning and observation the
evil results. The abhorrence occasionally foiling is no
valid argument against the feeling being instinctive, for
any instinct may occasionally fail or become vitiated, as
sometimes occurs with parental love and the social sym-
pathies. In the case of man, the question whether evil
follows from close interbreeding will probably never be
answered by direct evidence, as he propagates his kind
so slowly and cannot be subjected to experiment; but
the almost universal practice of all races at all times of
avoiding closely-related marriages is an alignment of con-
siderable Aveight ; and whatever conclusion we arrive at
in regard to the higher animals may be safely extended
to man.

Turning now to Birds : in the case of the Fowl a whole array of
authorities could be given against too close interbreeding. Sir J.
Sebright positively asserts that he made many trials, and that his
fowls, when thus treated, became long in the legs, small in the
body, and bad breeders.25 He produced the famous Sebright Ban-
tams by complicated crosses, and by breeding in-and-in ; and since
his time there has been mvich close interbreeding with these Ban-
tams ; and they are now notoriously bad breeders. I have seen
Silver Bantams, directly descended from his stock, which had be-
come almost as barren as hybrids ; for not a single chicken had
been that year hatched from two full nests of eggs. Mr. Hewitt
says that with these Bantams the sterility of the male stands, with
rare exceptions, in the closest relation with their loss of certain
secondary male characters : he adds, " I have noticed, as a general
" rule, that even the slightest deviation from feminine character in
" the tail of the male Sebright — say the elongation by only half an
"inch of the two principal tail-feathers — brings with it improved
" probability of increased fertility." 2B

26 ' The Art of Improving the Breed,' 26 'The Poultry Book,' by W. B. Te-

['. 18. getmeier, 1866, p. 245.

Chap. XVII. EVIL FROM INTERBREEDING. 155

Mr. Wright states " that Mr. Clark, " whose fighting-cocks were
so " notorious, continued to breed from his own kind till they lost
- their disposition to fight, but stood to be cut up without making
" any resistance, and were so reduced in size as to be under those
" weights required for the best prizes ; but on obtaining a cross from
" Mr. Leighton, they again resumed their former courage and
" weight." It should be borne in mind that game-cocks before they
fought were always weighed, so that nothing was left to the imagi-
nation about any reduction or increase of weight. Mr. Clark does
not seem to have bred from brothers and sisters, which is the most
inj urious kind of union ; and he found, after repeated trials, that there
was a greater reduction in weight in the young from a father paired
with his daughter, than from a mother with her son. I may add
that Mr. Eyton, of Eyton, the well-known ornithologist, who is a large
breeder of Grey Dorkings, informs me that they certainly diminish
in size, and become less prolific, unless a cross with another strain
is occasionally obtained. So it is with Malays, according to Mr.
Hewitt, as far as size is concerned.28

An experienced writer 29 remarks that the same amateur, as is
well known, seldom long maintains the superiority of his birds ;
and this, he adds, undoubtedly is due to all his stock " being of the
same blood ;" hence it is indispensable that he should occasionally
procure a bird of another strain. But this is not necessary with
those who keep a stock of fowls at different stations. ■ Thus, Mr.
Ballance, who has bred Malays for thirty years, and has won more
prizes with these birds than any other fancier in England, says
that breeding in-and-in does not necessarily cause deterioration ;
" but all depends upon how this is managed." " My plan has been
"to keep about five or six distinct runs, and to rear about two
" hundred or three hundred chickens each year, and select the best
" birds from each run for crossing. I thus secure sufficient cross-
" ing to prevent deterioration." 30

We thus see that there is almost complete unanimity with poid-
try-breeders that, when fowls are kept at the same place, evil
quickly follows from interbreeding carried on to an extent which
would be disregarded in the case of most quadrupeds. On the

17 'Journal Royal Agricult. Soc ' cautious notto repeat the in-and-in breed

1840, vol. vii. p. 205; see also Ferguson ing."

on the Fowl, pp. 83, 317 ; see also ' The 28 ' The Poultry Book,' by W. B. Te-

Poultry Book,' by Tegetmeier, 1SG6, p. getmeier, 1S06, p. T9.

185, with respect to the extent to which -° ' The Poultry Chronicle,' 1S54, vol.

cock-figbtera found that they could ven- i. p. 43.

tore to breed in-and-in, viz., occasionally 2'' ' The Poultry Book,' by W. I!. Te-

a h«rn with her own son ; "but they were getmeier, I860, p. 79.

156 GOOD FROM CROSSING. Chap. xvji.

other hand, it is a generally received opinion that cross-bred chick-
ens are the hardiest and most easily reared.31 Mr. Tegetmeier,
who has carefully attended to poultry of all breeds, "says32 that
Dorking hens, allowed to run with Houdan or Crevecoeur cocks,
" produce in the early spring chickens that for size, hardihood,
" early maturity, and fitness for the market, surpass those of any
" pure breed that we have ever raised." Mr. Hewitt gives it as
a general rule with fowls, that crossing the breed increases their
size. He makes this remark after stating that hybrids from the
pheasant and fowl are considerably larger than either progenitor :
so again, hybrids from the male golden pheasant and hen common
pheasant " are of far larger size than either parent-bird." 33 To this
subject of the increased size of hybrids I shall presently return.

With Pigeons, breeders are unanimous, as previously stated, that
it is absolutely indispensable, notwithstanding the trouble and ex-
pense thus caused, occasionally to cross their much-prized birds
with individuals of another strain, but belonging, of course, to the
same variety. It deserves notice that, when large size is one of the
desired characters, as with pouters, 34 the evil effects of close inter-
breeding are much sooner perceived than when small birds, such
as short-faced tumblers, are valued. The extreme delicacy of the
high fancy breeds, such as these tumblers and improved English
carriers, is remarkable ; they are liable to many diseases, and often
die in the egg or during the first moult ; and their eggs have gene-
rally to be hatched under foster-mothers. Although these highly-
prized birds have invariably been subjected to much close inter-
breeding, yet their extreme delicacy of constitution cannot perhaps
be thus fully explained. Mr. Yarrell informed me that Sir J. Se-
bright continued closely interbreeding some owl-pigeons, until from
their extreme sterility he as nearly as possible lost the whole fam-
ily. Mr. Brent 35 tried to raise a breed of trumpeters, by crossing
a common pigeon, and recrossing the daughter, granddaughter,
great-granddaughter, and great-great-granddaughter, with the
same male trumpeter, until he obtained a bird with i|- of trum-
peter's blood ; but then the experiment failed, for " breeding so
"close stopped reproduction." The experienced Neumeister SB also
asserts that the offspring from dovecotes and various other breeds
are " generally very fertile and hardy birds :" so again, MM. Boitard

31 'The Poultry Chronicle,' vol. i. p. S4 'A Treatise on Fancy Pigeons,' by
89. J. M. Eaton, p. 56.

32 ' The Poultry Book,' 1866, p. 210. 35 ' The Pigeon Book,' p. 46.

33 Ibid, 1S66, p. 167; and 'Poultry 36 ' Das Ganze der Taubenzucht,' 1837,
Chronicle,' vol. iii., 1S55, p. 15. s. 18.

Cuap. xvii. EVIL FROM INTERBREEDING. 157

and Corbie,'7 after forty-five years' experience, recommend persons
to cross their breeds for amusement ; for, if they fail to make inter-
esting birds, they will succeed under an economical point of view,
" as it is found that mongrels are more fertile than pigeons of pure
" race."

I will refer only to one other animal, namely, the Hive-bee, be-
cause a distinguished entomologist has advanced this as a case of
inevitable close interbreeding. As the hive is tenanted by a single
female, it might have been thought that her male and female off-
spring would always have bred together, more especially as bees
of different hives are hostile to each other ; a strange worker being
almost always attacked when trying to enter another hive. But
Mr. Tegetmeier has shown38 that this instinct does not apply to
drones, which are permitted to enter any hive ; so that there is
no a priori improbability of a queen receiving a foreign drone.
The fact of the imion invariably and necessarily taking place on
the wing, during the queen's nuptial flight, seems to be a special
provision against continued interbreeding. However this may be,
experience has shown, since the introduction of the yellow-banded
Ligurian race into Germany and England, that bees freely cross :
Mr. Woodbury, who introduced Ligurian bees into Devonshire,
found during a single season that three stocks, at distances of
from one to two miles from his hives, were crossed by his drones.
In one case the Ligurian drones must have flown over the city of
Exeter, and over several intermediate hives. On another occasion
several common black queens were crossed by Ligurian drones at a
distance of from one to .three and a half miles.39

Plants.

"When a single plant of a new species is introduced into any coun-
try, if propagated by seed, many individuals will soon be raised, so
that if the proper insects be present there will be crossing. With
newly-introduced trees or other plants not propagated by seed we
are not here concerned. With old-established plants it is an almost
universal practice occasionally to make exchanges of seed, by which
means individuals which have been exposed to different conditions
of life, — and this, as we have seen, diminishes the evil from close
interbreeding, — will occasionally be introduced into each district.

Experiments have not been tried on the effects of fertilising

37 'Les Pigeons,' 1S24, p. 35. M 'Journal of Horticulture,' 1S6I, pp.

88 ' Proc. Entomolog. Soc.,' Aug. 6th, 39, 77, 153; and 1SC4, p. 206.
1880, p. 126.

158 GOOD FROM CROSSING. Chap. XVII.

flowers with tlieir own pollen during several genera'lons. But wo
shall presently see that certain plants, either normally or abnormal-
ly, are more or less sterile, even in the first generation, when ferti-
lised by their own pollen. Although nothing is directly known on
the evil effects of* long-continued close interbreeding with plants, the
converse proposition that great good is derived from crossing is well
established.

With respect to the crossing of individuals belonging to the same
sub-variety, Gartner, whose accuracy and experience exceeded that
of all other hybridisers, states40 that he has many times observed
good effects from this step, especially with exotic genera, of which
the fertility is somewhat impaired, such as Passiflora, Lobelia, and
Fuchsia. Herbert also says/1 " I am inclined to think that I have
"derived advantage from impregnating the flower from which I
" wished to obtain seed with pollen from another individual of the
" same variety, or at least from another flower, rather than with its
" own." Again, Professor Lecoq asserts that he has ascertained
that crossed offspring are more vigorous and robust than their
parents.42

General statements of this kind, however, can seldom be fully
trusted ; consequently I have begun a series of experiments, which,
if they continue to give the same results as hitherto, will for ever
settle the question of the good effects of crossing two distinct plants
of the same variety, and of the evil effects of self-fertilisation. A
clear ligrht will thus also be thrown on the fact that flowers are in-
variably constructed so as to permit, or favour, or necessitate the
union of two individuals. We shall clearly understand why monoe-
cious and dioecious, — why dimorphic and trimorphic plants exist,
and many other such cases. The plan which I have followed in my
experiments is to grow plants in the same pot, or in pots of the same
size, or close together in the open ground ; to carefully exclude in-
sects ; and then to fertilise some of the flowers with pollen from the
same flower, and others on the same plant with pollen from a
distinct but adjoining plant. In many, but not all, of these expe-
riments, the crossed plants yielded much more seed than the self-
fertilised plants ; and I have never seen the reversed case. The self-
fertilised and crossed seeds thus obtained were allowed to germi
nate in the same glass vessel on damp sand ; and as the seeds suc-
cessively germinated, they were planted in pairs on opposite sides
of the same pot, with a superficial partition between them, and

40 'Beitrage zur Kenntniss der Be- 42 ' De la Fccondation,1 2d edit., 1862,
fruchtung,' 1S44, s. 300. p. 79.

41 ' Amaryllidace*,1 p. Stl.

Chap. XVII. EVIL FROM INTERBREEDING. 159

■wore placed so as to bo equally exposed to the light. In other cases
the self-fertilised and crossed seeds were simply sown on opposite
sides of the same small pot. I have, in short, followed different
plans, hut in every eas.^ have taken all tho precautions which I
could think of, .so that the two lots should he equally favoured.
Now, I have carefully observed the growth of plants raised from
crossed and self-fertilised seed, from their germination to maturity,
in species of the following genera, namely, Brassica, Lathyrus, Lu-
pinus, Lobelia, Lactuca, Dianthus, Myosotis, Petunia, Linaria, Calceo-
laria. Mimulus, and Ipomoea, and the difference in their powers of
growth and of withstanding in certain cases unfavourable conditions,
was most manifest and strongly marked. It is of importance that the
two lots of seed should be sown or planted on opposite sides of the
same pot, so that the seedlings may struggle against each other ; for
if sown separately in ample and good soil, there is often but little
difference in their growth.

I will briefly describe the two 'most striking cases as yet observed
by me. Six crossed and six self-fertilised seeds of Tpomcnn purpurea,
from plants treated in the manner above described, were planted as
soon as they had germinated, in pairs on opposite sides of two pots,
and rods of equal thickness were given them to twine up. Five of
the crossed plants grew from the first more quickly than the oppo-
sed self-fertilised plants ; the sixth, however, was weakly and was
for a time beaten, but at last its sounder constitution prevailed and
it shot ahead of its antagonist. As soon as each crossed plant
reached the top of its seven-foot rod its fellow was measured, and
the result was that when the crossed plants were seven feet high,
the self-fertilised had attained the average height of only five feet
four and a half inches. The crossed plants flowered a little before,
and more profusely than the self-fertilised plants. On opposite sides
of another small pot a large number of crossed and self-fertilised
seeds were sown, so that they had to struggle for bare existence ; a
single rod was given to each lot : here again the crossed plants
showed from the first their advantage ; they never quite reached the
summit of the seven-foot rod, but relatively to the self-fertilised
plants their average height was as seven feet to five feet two inches.
The experiment was repeated in the two following generations with
plants raised from the self-fertilised and crossed plants, treated in
exactly the same manner, and with nearly the same result. In the
second generation, the crossed plants, which were again crossed,
produced 121 seed-capsules, whilst the self-fertilised plants, again
self-fertilised, produced only 84 capsules.

Some flowers of the Mimulus hit, ux were fertilised with their own
pollen, and others were crossed with pollen from distinct plants

160 GOOD FROM CROSSING. Chap. XVII.

growing in the same pot. The seeds after germinating were thick-
ly planted on opposite sides of a pot. The seedlings were at first
equal in height ; but when the young crossed plants were exactly
half an inch, the self-fertilised plants were only a quarter of an inch
high. But this inequality did not continue, for, when the crossed
plants were four and a half inches high, the self-fertilised were
three inches ; and they retained the same relative difference till
their growth was complete. The crossed plants looked far more vi-
gorous than the uncrossed, and flowered before them ; they pro-
duced also a far greater number of flowers, which yielded capsules
(judging, however, from only a few) containing more seeds. As in
the former case, the experiment was repeated in the same manner
during the next two generations, and with exactly the same result.
Had I not watched these plants of the Mimulus and Ipomoea during
their whole growth, I could not have believed it possible, that a dif-
rerence apparently so slight, as that of the pollen being taken from
the same flower, and from a distinct plant growing in the same
small pot, could have made so wonderful a difference in the growth
and vigour of the plants thus produced. This, under a physiologi-
cal point of view, is a most remarkable phenomenon.

With respect to the benefit derived from crossing distinct varie-
ties, plenty of evidence has been published. Sageret 43 repeatedly
speaks in strong terms of the vigour of melons raised by crossing
different varieties, and adds that they are more easily fertilised than
common melons, and produce numerous good seed. Here follows
the evidence of an English gardener : " "I have this summer met
"' with better success in my cultivation of melons, in an unprotected
" state, from the seeds of hybrids (i. e. mongrels) obtained by cross
" impregnation, than with old varieties. The offspring of three
" different hybridisations (one more especially, of which the parents
" were the two most dissimilar varieties I could select) each yielded
" more ample and finer produce than any one of between twenty
" and thirty established varieties."

Andrew Knight ib believed that his seedlings from crossed varie-
ties of the apple exhibited increased vigour and luxuriance ; and M.
Chevreul 46 alludes to the extreme vigour of some of the crossed
fruit-trees raised by Sageret.

By crossing reciprocally the tallest and shortest peas, Knight47

43 ' Memoire sur les Cucurbitacees,' 46 ' Annal. des Sc. Nat.,' 3rd series,
pp. 36, 28, 30. Bot,, torn. vi. p. 189.

44 Loudon's 'Gard. Mag.,' vol. viii., 47 ' Philosophical Transactions,' 1799,
1S32, p. 52. p. 200.

46 'Transact, flout. Soc.,' vol. 1. p. 25.

Chap. XVII. EVIL FROM INTERBREEDING. 161

says, " I had in this experiment a striking instance of the stimula-
" tive effects of crossing the hrceds ; for the smallest variety, whose
" height rarely exceeded two feet, was increased to six feet ; whilst the
" height of the large and luxuriant kind was very little diminished."
Mr. Laxton gave me seed-peas produced from crosses hetween four
distinct kinds ; and the plants thus raised were extraordinarily vig-
orous, being in each case from one to two or three feet taller than the
parent-forms growing close alongside them.

Wiegmann " made many crosses bet ween, several varieties of cab-
bage ; and he speaks with astonishment of the vigour and height of
the mongrels, which excited the amazement of all the gardeners
who beheld them. Mr. Chaundy raised a great number of mongrels
by planting together six distinct varieties of cabbage. These mon-
grels displayed an infinite diversity of character ; " But the most re-
"markable circumstance was, that, while all the other cabbages and
" borecoles in the nursery were destroyed by a severe winter, these
" hybrids were little injured, and supplied the kitchen when there
" was no other cabbage to be had."

Mr. Maund exhibited before the Royal Agricultural Society49
specimens of crossed wheat, together with their parent varieties ;
and the editor states that they were intermediate in character,
" united with that greater vigour of growth, which it appears, in
the vegetable as in the animal world, is the result of a first cross."
Knight also crossed several varieties of wheat,50 and he says " that
" in the years 1795 and 1796, when almost the whole crop of corn
" in the island was blighted, the varieties thus obtained, and these
only, escaped in this neighbourhood, though sown in several differ-
ent soils and situations."

Here is a remarkable case : M. Clotzsch51 crossed Pinus sylvestris
and nigricans, Qucrcus rdbur and pedunculated, Alnus glutinosa and
incana, Ulmus campestns and effusa ; and the cross-fertilised seeds,
as well as seeds of the pure parent-trees, were all sown a-t the same
time and in the same place. The result was, that after an interval
of eight years, the hybrids were one-third taller than the pure-trees !

The facts above given refer to undoubted varieties, excepting the
trees crossed by Clotzsch, which are ranked by various botanists as
strongly-marked races, sub-species, or species. That true hybrids
raised from entirely distinct species, though they lose in fertility,

4» ' Ueber die Bastarderzeugung,' 1S2S, 49 ' Gardener's Chron.,' 1S4G, p. 601.

s. 32, 33. For Mr. Chaundy's case, see 60 ' Philosoph. Transact.,' 1799, p. 201

Loudon's ' Gard. Mag.,' vol. vii., 1881, ft, 61 Quoted in ' Bull. Bot. Soc. France

C90. vol. ii., 1S55, p. 827.

162 GOOD FROM CROSSING. Chap. XVII.

often gain in size and constitutional vigour, is certain. It would be
superfluous to quote any facts ; for all experimenters. Kolreuter,
Gartner, Herbert, Sageret, Locoq, and Naudin, bave been struck
with tbe wonderful vigour, height, size, tenacity of life, precocity, and
bardiness of tbeir bybrid productions. Gartner i2 sums up bis con-
viction on this head in the strongest terms. Kolreuter H gives
numerous precise niesurenients of the weight and height of bis
hybrids in comparison with measurements of both parent-forms ;
and speaks with astonishment of their " statura portentosa," their
" ambitus vastlssimus ac altitudo valde coaspkua." Some exceptions
to the rule in tbe case of very sterile hybrids have, however, been
noticed by Gartner and Herbert ; but tbe most striking exceptions
are given by Max Wicbura,64 wbo found that hybrid willows were
generally tender in constitution, dwarf, and shortJived.
. Kolreuter explains the vast increase in tbe size of the roots, stems,
&c, of his bybrids, as tbe result of a sort of compensation due to
tbeir sterility, in the same way as many emasculated animals are
larger tban tbe perfect males. Tbis view seems at first sight ex-
tremely probable, and has been accepted by various authors ;55 but
Gartner69 bas well remarked tbat there is much difficulty in fully
admitting it ; for with many hybrids there is no parallelism between
the degree of tbeir sterility and tbeir increased size and vigour. Tbe
most striking instances of luxuriant growth have been observed with
hybrids which were not sterile in any extreme degree. In the genus
Mirabilis, certain hybrids are unusually fertile, and tbeir extraor-
dinary luxuriance of growth, together with their enormous roots,67
have been transmitted to tbeir progeny. Tbe increased size of tbe
bybrids produced between the fowl and pheasant, and between dis-
tinct species of pheasants, has been already noticed. Tbe result in
all cases is probably in part due to tbe saving of nutriment and vital
force through tbe sexual organs not acting, or acting imperfectly,
but more especially to tbe general law of good being derived from
a cross. For it deserves especial attention tbat mongrel animals
and plants, which are so far from being sterile tbat tbeir fertibty is
often actually augmented, have, as previously shown, their size,

52 Gartner, 'B.istarderzeugung,' s. 259, 55 Max Wichura fully accepts tbis
5tS, 526 et seq. view (' Bastardbefruchtung,' s. 43), as

53 ' Fortsetzung,' 1TC3, s. 29 ; ' Diitte does the Rev. M. J. Berkeley, in
Fortsetzung,' s. 44, 96 ; ' Act. Acad. St. 'Journal of Hort. Soc.,' Jan. 1S66, p. 70.
Petersburg,' 1782, part ii., p. 251 ; ' Nova 58 ' Bastarderzeugung,' s. 394, 526, 523.
Acta,' 1793, pp. 391, 394 ; ' Nova Acta,' " Kolreuter, Nova Act,' 1795, p.
1795, pp. 316,323. 316.

6* ' Die Bastardbefruchtung,' &c,

1865, s. 31, 41, 42. *"

Chap. xvii. SELF-IMPOTENT PLANTS. 163

hardiness, and constitutional vigour generally increased. It is not
a little remarkable that an accession of vigour and size should thus
arise under the opposite contingencies of increased and diminished
fertility.

It is a perfectly well ascertained fact 58 that hybrids will invariably
breed more readily with either pure parent, and not rarely with a
distinct species, than with each other. Herbert is inclined to explain
even this fact by the advantage derived from a cross ; but Gartner
more j ustly accounts for it by the pollen of the hybrid, and probably
its ovules, being in some degree vitiated, whereas the pollen and
ovules of both pure parents and of any third species are sound.
Nevertheless there are some well-ascertained and remarkable facts,
which, as we shall immediately see, show that the act of crossing
in itself undoubtedly tends to increase or re-establish the fertility of
hybrids.

On certain Hermaphrodite Plants ichich, either normally
or abnormally, require to be fertilised by pollen from a
distinct individual or species.

The facts now to be given differ from those hitherto
detailed, as the self-sterility does not here result from
long-continued, close interbreeding. These facts are,
however, connected with our present subject, because a
cross with a distinct individual is shown to be either ne-
cessary or advantageous. Dimorphic and trimorphic
plants, though they are hermaphrodites, must be recipro-
cally crossed, one set of forms by the other, in order to
be fully fertile, and in some cases to be fertile in any
degree. But I should not have noticed these plants, had
it not been for the following cases given by Dr. Hilde-
brand:59—

Prim ukt sinen&is is a reciprocally dimorphic species : Dr. Hilde-
brand fertilised twenty-eight flowers of both forms, each by pollen
of the other form, and obtained the full number of capsules contain-
ing on an average 427 seed per capsule ; here we have complete
• and normal fertility. He then fertilised forty-two flowers of both

69 Gartner, ' Bastarderzeugung,' s. *• 'Botanlsche Zeitung,' Jan. 1S64,

30. b. 3.

164 GOOD FROM CROSSING. Chap. XVII.

forms with pollen of the same form, but taken from a distinct plant,
and all produced capsules containing on an average only 196 seed.
Lastly, and here we come to our more immediate point, he fertilised
forty-eight flowers of both forms with pollen of the same form, taken
from the same flower, and now he obtained only thirty-two capsules,
and these contained on an average 186 seed, or one less per capsule
than in the former case. So that, with these illegitimate unions,
the act of impregnation is less assured, and the fertility slightly less,
when the pollen and ovules belong to the same flower, than when
belonging to two distinct individuals of the same form. Dr. Hilde-
brand has recently made analogous experiments on the long-styled
form of Oxalis rosea, with the same result.60

It has recently been discovered that certain plants,
•whilst growing in their native country under natural
conditions, cannot be fertilised with pollen from the same
plant. They are sometimes so utterly self-impotent,
that, though they can readily be fertilised by the pollen
of a distinct species or even distinct genus, yet, -wonderful
as the fact is, they never produce a single seed by their
own pollen. In some cases, moreover, the plant's own
pollen and stigma mutually act on each other in a dele-
terious manner. Most of the facts to be given relate to
Orchids, but I will commence with a plant belonging to
a widely different family.

Sixty-three flowers of Corydalis cava, born on distinct plants, were
fertilised by Dr. Hildebrand " with pollen from other plants of the
same species ; and fifty-eight capsules were obtained, including on
an average 4-5 seed in each. He then fertilised sixteen flowers pro-
duced by the same raceme, one with another, but obtained only
three capsules, one of which alone contained any good seeds, namely,
two in number. Lastly, he fertilised twenty-seven flowers, each
with its own pollen ; he left also fifty-seven flowers to be spontane-
ously fertilised, and this would certainly have ensued if it had been
possible, for the anthers not only touch the stigma, but the pollen-
tubes were seen by Dr. Hildebrand to penetrate it ; nevertheless
these eighty-four flowers did not produce a single seed-capsule !
This whole case is highly instructive, as it shows how widely dif-

60 ' Monatsbericht Akad. Wissen,' 61 International Hort. Congress,

Berlin, 1S66, s. 872. London, 1S66.

Our. xvii. SELF-IMPOTENT PLANTS. 165

fercnt the action of the same pollen is, according as it is placed on
the stigma of the same flower, or on that of another flower on the
same raceme, or on that of a distinct plant.

With exotic Orchids several analogous cases have been observed,
chiefly by Mr. John Scott.02 OnruUum splutcchttum has effective
pollen, for with it Mr. Scott fertilised two distinct species ; its
ovules are likewise capable of impregnation, for they were readily
fertilised by the pollen of 0. ilicariratum J nevertheless, between
one and two hundred flowers fertilised by their own pollen did not
produce a single capsule, though the stigmas were penetrated by
the pollen-tubes. Mr. Robinson Munro, of the Royal Botanic
Gardens of Edinburgh, also informs me (1864) that a hundred and
twenty flowers of this same species were fertilised by him with
their own pollen, and did not produce a capsule, but eight flowers
fertilised by the pollen of 0. divavicatum produced four fine cap-
sules: again, between two and three hundred flowers of 0. dirari-
aitum, fertilised by their own pollen, did not set a capsule, but
twelve flowers fertilised by 0. flexuosum produced eight fine cap-
sules : so that here we have three utterly self-impotent species,
with their male and female organs perfect, as shown by their
mutual fertilisation. In these cases fertilisation was effected only
by the aid of a distinct species. But, as we shall presently see,
distinct plants, raised from seed, of Oncidlum flexuosum, and prob-
ably of the other species, would have been perfectly capable of
fertilising each other, for this is the natural process. Again, Mr.
Scott found that the pollen of a plant of 0. microcldlum was good,
for with it he fertilised two distinct species ; he found its ovules
good, for they could be fertilised by the pollen of one of these
species, and by the pollen of a distinct plant of 0. microchilum ;
but they could not be fertilised by pollen of the same plant, though
the pollen-tubes penetrated the stigma. An analogous case has
been recorded byM. Riviere,63 with two plants of 0. Cavendishianum,
which were both self-sterile, but reciprocally fertilised each other.
All these cases refer to the genus Oncidium, but Mr. Scott found
that MaxiUaria atro-rubens was " totally insusceptible of fertilisa-
tion with its own pollen," but fertilised, and was fertilised by, a
widely distinct species, viz. M. squnlens.

As these orchids had grown under unnatural conditions, in hot-
houses, I concluded without hesitation that their self-sterility was

82 ' Proc. Bnt. Soc. of Edinburgh,' Bot,, 1S64, p. 183.

May, 1S63: these observations are given 63 Prof. Lecoq, ' De la Fecondation,

in abstract, and others are added in the 2nd edit., 1S62, p. 76.
'Journal of Proc. of Linn. Soc.,' vol. viii.

166 GOOD FROM CROSSING. Chap. XVH.

due to tins cause. But Fritz Miiller informs me that at Desterro,
in Brazil, lie fertilized above one hundred flowers of the above-
mentioned Oncidium flexuosum, which is there endemic, with its
own pollen, and with that taken from distinct plants; all the
former were sterile, whilst those fertilised by pollen from any other
plant of the same species were fertile. During the first three days
there was no difference in the action of the two kinds of pollen :
that placed on the stigma of the same plant separated in the usual
manner into grains, and emitted tubes which penetrated the column,
and the stigmatic chamber shut itself ; but the flowers alone which
had been fertilised by pollen taken from a distinct plant produced
seed-capsules. On a subsequent occasion these experiments were
repeated on a large scale with the same result. Fritz Miiller
found that four other endemic species of Oncidium were in like
manner utterly sterile with their own pollen, but fertile with that
from any other plant : some of them likewise produced seed-cap-
sules when impregnated with pollen of widely distinct genera, such
as Leptotes, Cyrtopodium, and Rodriguezia! Oncidium crispum,
however, differs from the foregoing species in varying much in its
self-sterility ; some plants producing fine pods with their own
pollen, others failing to do so ; in two or three instances, Fritz
Miiller observed that the pods produced by pollen taken from a
distinct flower on the same plant, were larger than those produced
by the flower's own pollen. In Epidendrum cinnabarinum, an or-
chid belonging to another division of the family, fine pods were
produced by the plant's own pollen, but they, contained by weight
only about half as much Feed as the capsules which had been
fertilized by pollen from a distinct plant, and in one instance from
a distinct species ; moreover, a very large proportion, and in some
cases nearly all the seed produced by the plant's own pollen, was
embryonless and worthless. Some self-fertilized capsules of a Max-
illaria were in a similar state.

Another observation made by Fritz Miiller is highly remarkable,
namely, that with various orchids the plant's own pollen not only
fails to impregnate the flower, but acts on the stigma, and is acted
on, in an injurious or poisonous manner. This is shown by the
surface of the stigma in contact with the pollen, and by the pollen
itself, becoming in from three to five days dark brown, and then
decaying. The discolouration and decay are not caused by para-
sitic cryptogams, which were observed by Fritz Miiller in only a
single instance. These changes are well shown by placing on the
same stigma, at the same time, the plant's own pollen and that
from a distinct plant of the same species, or of another species, or
even of another and widely remote genus. Thus, on the stigma

Chap. xvii. SELF-IMPOTENT PLANTS. 107

of Onridium flexuosum, the plant's own pollen and that from a
distinct plant were placed side by side, and in five days' time the
latter was perfectly fresh, whilst the plant's own pollen was brown.
On the other hand, when the pollen of a distinct plant of the
Oncidium flexuosum, and of the Epidendrum zebra (?iov. spec. ?),
were placed together on the same stigma, they behaved in exactly
the same manner, the grains separating, emitting tubes, and pene-
trating the stigma, so that the two pollen-masses, after an interval
of eleven days, could not be distinguished except by the difference
of their caudicles, which, of course, undergo no change. Fritz
Miiller has, moreover, made a large number of crosses between
orchids belonging to distinct species and genera, and he finds that
in all cases when the flowers are not fertilised their footstalks
first begin to wither ; and the withering slowly spreads upwards
until the germens fall off, after an interval of one or two weeks,
and in one instance of between six and seven weeks ; but even
in this latter case, and in most other cases, the pollen and stigma
remained in appearance fresh. Occasionally, however, the pollen
becomes brownish, generally on the external surface, and not in
contact with the stigma, as is invariably the case when the plant's
own pollen is applied.

Fritz Miiller observed the poisonous action of the plant's own
pollen in the above-mentioned Oncidium flexuosum, 0. iinicorne,
pubes ('?), and in two other unnamed species. Also in two species of
Rodriguezia, in two of Notylia, in one of Burlingtonia, and of a
fourth genus in the same group. In all these cases, except the last,
it was proved that the flowers were, as might have been expected,
fertile with pollen from a distinct plant of the same species. Nu-
merous flowers of one species of Notylia were fertilized with pollen
from the same raceme ; in two days' time they all withered, the
germens began to shrink, the pollen-masses became dark brown,
and not one pollen-grain emitted a tube. So that in this orchid the
injurious action of the plant's own pollen is more rapid than with
Onridium flexuosum. Eight other flowers on the same raceme were
fertilized with pollen from a distinct plant of the same species : two
of these were dissected, and their stigmas were found to be pene-
trated by numberless pollen-tubes ; and the germens of the other
six flowers became well developed. On a subsequent occasion many
other flowers were fertilized with their own pollen, and all fell off
dead in a few days ; whilst some flowers on the same raceme which
had been left simply unfertilised adhered and long remained fresh.
We have seen that in cross-unions between extremely distinct or-
chids the pollen long remains undecayed ; but Notylia behaved in
this respect differently ; for when its pollen was placed on the stig-

168 GOOD FROM CROSSING. Chap. XVII.

ma of Oncidium flexuosum, both the stigma and pollen quickly be-
came dark brown, in the same manner as if the plant's own pollen
had been applied.

Fritz Miiller suggests that, as in all these cases the plant's own
p&llen is not only impotent (thus effectually preventing self-fertili-
zation), but likewise prevents, as was ascertained in the case of the
Notylia and Oncidium flexuosum, the action of subsequently ap-
plied pollen from a distinct individual, it would be an advantage to
the plant to have its own pollen rendered more and more deleteri-
ous ; for the germens would thus quickly be killed, and, dropping
off, there would be no further waste in nourishing a part which
ultimately could be of no avail. Fritz Miiller's discovery that a
plant's own pollen and stigma in some cases act on each other as if
mutually poisonous, is certainly most remarkable.

We now come to cases closely analogous with those
just given, but different, inasmuch as individual plants
alone of the sj^ecies are self-impotent. This self-impotence
does not depend on the pollen or ovules being in a state
unfit for fertilisation, for both have been found effective
in union with other plants of the same or of a distinct
species. The fact of these plants having spontaneously
acquired so peculiar a constitution, that they can be fer-
tilised more readily by the pollen of a distinct species
than by their own, is remarkable. These abnormal cases,
as well as the foregoing normal cases, in which certain
orchids, for instance, can be much more easily fertilised
by the pollen of a distinct species than by their own, are
exactly the reverse of what occurs with all ordinary
species. For in these latter the two sexual elements of
the same individual plant are capable of freely acting on
each other ; but are so constituted that they are more or
less impotent when brought into union with the sexual
elements of a distinct species, and produce more or less
sterile hybrids. It would appear that the pollen or
ovules, or both, of the individual plants which are in this
abnormal state, have been affected in some strange man-
ner by the conditions to which they themselves or their
parents have been exposed ; but whilst thus rendered

Chap. XVII. SELF-IMPOTENT PLANTS. 169

self-sterile, they have retained the capacity common to
most species of partially fertilizing and being partially
fertilized by allied forms. However this may be, the
subject, to a certain extent, is related to our general con-
clusion that good is derived from the act of crossing.

Gartner experimented on two plants of Lobelia fulgens, brought
from separate places, and found 64 that their pollen was good, for he
fertilised with it L. cardinalis and syphilitica; their ovules were
likewise good, for they were fertilised by the pollen of these same
two species ; but these two plants of L. fulgens could not be fertil-
ised by their own pollen, as can generally be effected with perfect
ease with this species. Again, the pollen of a plant of Verbascum
nigrum grown in a pot was found by Gartner 65 capable of fertilis-
ing T'. lyehnitis and V. Austriacum ; the ovules could be fertilised
by the pollen of V. thapsus ; but the flowers could not be fertilised
by their own pollen. Kolreuter, also,66 gives the case of three
garden plants of Verbascum phainiceum, which bore during two
years many flowers ; these he successfully fertilized by the pollen
Df no less than four distinct species, but they produced not a seed
with their own apparently good pollen ; subsequently these same
plants, and others raised from seed, assumed a strangely fluctuating
?ondition, being temporarily sterile on the male or female side, or
:m both sides, and sometimes fertile on both sides ; but two of the
plants were perfectly fertile throughout the summer.

It appears67 that certain flowers on certain plants of Lilium can-
iidum can be fertilised more easily by pollen from a distinct indi-
vidual than by their own. So, again, with the varieties of the
potato. Tinzmann,68 who made many trials with this plant, says
chat pollen from another variety sometimes " exerts a powerful in-
' fluence, and I have found sorts of potatoes which would not bear
' seed from impregnation with the pollen of their own flowers,
' would bear it when impregnated with other pollen." It does not,
however, appear to have been proved that the pollen which failed
CO art on the flower's own stigma was in itself good.

In the genus Passiflora it has long been known that several
species do not produce fruit, unless fertilised by pollen taken from
distinct species: thus, Mr. Mowbray69 found that he could not get

84 ' Bastarderzeugung,' s. 64, 357. ' Bastarderzeugung,' s. 334.

05 Mem, s. 357. 68 ' Gardener's Chronicle,' 1S46, p.

4(1 ' Zwelte Fortsetzung,' s. 10 ; ' Dritte 1S3.

Fort.,' s. 40. 69 ' Transact. Hort, Soc ,' vol. v!l.

" Duvernoy, quoted by Gartner, 1830, p. 95.

170 GOOD FROM CROSSING. Chap. XVII.

fruit from P. alata and racemom except by reciprocally fertilising
them with each other's pollen. Similar facts have been observed
in Germany and France ;70 and I have received two authentic ac-
counts of P. qyadraiir/ulnris, which never produced fruit with its
own pollen, but would do so freely when fertilised in one case with
the pollen of P. carulea, and in another case with that of P. ecb.dis.
So again, with respect to P. laiirifolia, a cultivator of much expe-
rience has recently remarked 71 that the flowers " must be fertilised
with the pollen of P. cosrulea, or of some other common kind, as
their own pollen will not fertilise them." But the fullest details
on this subject have been given by Mr. Scott :72 plants of Passiflor a
racemosa, can'idea, and alata flowered profusely during many years
in the Botanic Gardens of Edinburgh, and, though repeatedly fer-
tilised by Mr. Scott and by others with their own pollen, never pro-
duced any seed ; yet this occurred at once with all three species
when they were crossed together in various ways. But in the case
of P. ccerulea, three plants, two of which grew in the Botanic Gar-
dens, were all rendered fertile, merely by impregnating the one
with pollen of the other. The same result was attained in the
same manner with P. alata, but only with one plant out of three.
As so many self-sterile species have been mentioned, it may be
stated that in the case of P. gracilis, which is an annual, the flowers
are nearly as fertile with their own pollen as with that from a dis-
tinct plant ; thus sixteen flowers spontaneously self-fertilised pro-
duced fruit, each containing on an average 21"3 seed, whilst fruit
from fourteen crossed flowers contained 241 seed.

Returning to P.xalata, I have received (1866) some interesting
details from Mr. Robinson Munro. Three plants, including one in
England, have already been mentioned which were inveterately
self-sterile, and Mr. Munro informs me of several others which,
after repeated trials during many years, have been found in the
same predicament. At some other places, however, this species
fruits readily when fertilised with its own pollen. At Taymouth
Castle there is a plant winch was formerly grafted by Mr. Donald-
son on a distinct species, name unknown, and ever since the opera-
tion it has produced fruit in abundance by its own pollen ; so that
this small and unnatiiral change in the state of this plant has re-
stored its self-fertility ! Some of the seedlings from the Taymouth
Castle plant were found to be not only sterile with their own pollen,
but with each other's pollen, and with the pollen of distinct species.

70 Prof. Lecoq. ' De la Fecondation,' " 'Gardener's Chron.,' I860, p. 1068.

1S45, p. 70; Gartner, ' Bastarderzeu- 7a 'Journal of Proc. of Linn. Soc.,'

gung,' 6. 64. vol. viii., 1S64, p. 168.

Chap. XVII. SELF-IMPOTENT PLANTS. 171

Pollen from the Taymouth plant failed to fertilise certain plants of
tlie same species, but was successful on one plant in tlie Edinburgh
Botanic Gardens. Seedlings were raised from this latter union, and
some of their flowers were fertilised by Mr. Munro with their own
pollen ; but they were found to be as self-impotent as the mother-
plant had always proved, except when fertilised by the grafted
Taymouth plant, and, except, as we shall see, when fertilised In-
ner own seedlings. For Mr. Munro fertilised eighteen flowers on
the self-impotent mother-plant with pollen from these her own self-
impotent seedlings, and obtained, remarkable as the fact is, eigh-
teen fine capsules full of excellent seed ! I have met with no case
in regard to plants which shows so well as this of P. alata, on what
small and mysterious causes complete fertility or complete sterility
depends.

The facts hitherto given relate to the much-lessened or
completely destroyed fertility of pure species when im-
pregnated with their own pollen, in comparison with
their fertility when impregnated by distinct individuals
or distinct species ; but closely analogous facts have been
observed with hybrids.

Herbert states ™ that having in flower at the same time nine
hybrid Hippeastrums, of complicated origin, descended from several
species, he found that " almost every flower touched with pollen from
" another cross produced seed abundantly, and those which were
" touched with their own pollen either failed entirely, or formed
" slowly a pod of inferior size, with fewer seeds." In the ' Horti-
cultural Journal' he adds that, " the admission of the pollen of
" another -cross-bred Hippeastrum (however complicated the cross)
" to any one flower of the number, is almost sure to check the fruc-
" tification of the others." In a letter written to me in 1839, Dr.
Herbert says that he had already tried these experiments during
five consecutive years, and he subsequently repeated them, with the
same invariable result. He was thus led to make an analogous
trial on a pure species, namely, on the Hippeastrum aulicum, which
he had lately imported from Brazil : this bulb produced four flowers,
three of which were fertilised by their own pollen, and the .fourth
by the pollen of a triple cross between H. bulbuloswn, rer/ina', and
tittatum ; the result was, that " the ovaries of the three first flowers
" soon ceased to grow, and after a few days perished entirely :

73 ' Araaryllidacese,' 1537, p. 371 ; ■ Journal of Hort. Soc.,' vol. ii., 1847, p. 19.

172 GOOD FROM CROSSING. Chap. XVIL

" whereas the pod impregnated by the hybrid made vigorous and
" rapid progress to maturity, and bore good seed, which vegetated
" freely." This is, indeed, as Herbert remarks, "a strange truth,"
but not so strange as it then appeared.

As a confirmation of these statements, I may add that Mr. M.
Mayes,74 after much experience in crossing the snecies of Amaryl-
lis (Hippeastrum), says, " neither the species nor the hybrids will,
we are well aware, produce seed so abundantly from their own
pollen as from that of others." So, again, Mr. Bidwell, in New
South Wales,75 asserts that Amaryllis belladonna bears many more
seeds when fertilised by the pollen of Brunswigia {Amaryllis of
some authors) Josep7iina> or of B. multiflora, than when fertilised
by its own pollen. Mr. Beaton dusted four flowers of a Cyrtanthus
with their own pollen, and four with the pollen of Vattota {Amaryl-
lis) purpurea; on the seventh day "those which received their
" own pollen slackened their growth, and ultimately perished ; those
" which were crossed with the Vallota held on." 76 These latter cases,
however, relate to uncrossed species, like those before given with
respect to Passiflora, Orchids, &c, and are here referred to only be-
cause the plants belong to the same group of Amaryllidacese.

In the experiments on the hybrid Hippeastrums, if Herbert had
found that the pollen of two or three kinds alone had been more
efficient on certain kinds than their own pollen, it might have been
argued that these, from their mixed parentage, had a closer mutual
affinity than the others ; but this explanation is inadmissible, for
the trials were made reciprocally backwards and forwards on nine
different dybrids ; and a cross, whichever way taken, always proved
highly beneficial. I can add a striking and analogous case from
experiments made by the Bev. A. Rawson, of Bromley Common,
with some complex hybrids of Gladiolus. This skilful horticultur-
ist possessed a number of French varieties, differing from each other
only in the colour and Size of the flowers, all descended from Gan-
davensis, a well-known old hybrid, said to be descended from G.
Natalensis by the pollen of G. oppositiflorus.'1'' Mr. Rawson, after
repeated trials, found that none of the varieties would set seed with

74 Loudon's ' Gardener's Magazine,' 77 Mr. D. Beaton, in ' Journal of
vol. xi., 1S35, p. 260. Hort.,' 1S61, p. 453, Lecoq, however

75 'Gardener's Chronicle,' 185U, p. (' De la Fecond ,' 1S62, p. 369), states
4"0. that this hybrid is descended from G.

76 'Journal Hort. Soc.,' vol. v. p. 135. psiltacinus and cardinatig ; but this
The seedlings thus raised were given to is opposed to Herbert's experience, who
the Hort. Soc. ; but I find, on inquiry, found that the former species could not
that they unfortunately died the follow- be crossed.

Ing winter.

Chap. XVII. CONCLUSION. ltd

their own pollen, although taken from distinct plants of the same
variety, "which had, of course, been propagated by bulbs, but that
they all seeded freely with pollen from any other variety. To givo
two examples : Ophir did not produce a capsule with its own pollen,
but when fertilised with that of Janire, Brcnchleyensis, Vulcain,
and Linne, it produced ten fine capsules ; but the pollen of Ophir
was good, for when Linne was fertilised by it seven capsules were
produced. This latter variety, on the other hand, was utterly bar-
ren with its own pollen, which we have seen was perfectly efficient
on Ophir. Altogether, Mr. Rawson, in the year 1861, fertilised
twenty-six flowers borne by four varieties with pollen taken from
other varieties, and every single flower produced a fine seed-capsule ;
whereas fifty -two flowers on the same plants, fertilised at the same
time with their own pollen, did not yield a single seed-capsule. Mr.
Rawson fertilised, in some cases, the alternate flowers, and in other
cases all those down one side of the spike, with pollen of other
varieties, and the remaining flowers with their own pollen ; I saw
these plants when the capsules were nearly mature, and their curi-
ous arrangement at once brought full conviction to the mind that
an immense advantage had been derived from crossing these hybrids.
Lastly, I have heard from Dr. E. Bornet, of Antibes, who has
made numerous experiments in crossing the species of Cistus, but
has not yet published the results, that, when any of these hybrids
are fertile, they may be said to be, in regard to function, dioecious ;
" for the flowers are always sterile when the pistil is fertilised by
" pollen taken from the same flower or from flowers on the same
"plant. But they are often fertile if pollen be employed from a
" distinct individual of the same hybrid nature, or from a hybrid
" made by a reciprocal cross."

Conclusion. — The facts just given, which show that
certain plants are self-sterile, although both sexual ele-
ments are in a fit state for reproduction when united
with distinct individuals of the same or other species,
appear at first sight opposed to all analogy. The sexual
elements of the same flower have become, as already-
remarked, differentiated in relation to each other, almost
like those of two distinct species.

With respect to the species which, whilst living under
their natural conditions, have their reproductive organs
hi this peculiar state, we may conclude that it has been
naturally acquired for the sake of effectually preventing

174 GOOD FROM CROSSING. Chap. XVII.

self-fertilisation. The case is closely analogous with
dimorphic and trimorphic plants, which can he fully fer-
tilised only by plants belonging to the opposite form,
and not, as in the foregoing cases, indifferently by any
other plant. Some of these dimorphic plants are com-
pletely sterile with pollen taken from the same plant or
from the same form. It is interesting to observe the
graduated series from plants which, when fertilised by
their own pollen, yield the full number of seed, but with
the seedlings a little dwarfed in stature — to plants which
when self-fertilised yield few seeds — to those which yield
none — and, lastly, to those in which the plant's own
pollen and stigma act on each other like poison. This
peculiar state of the reproductive organs, when occurring
in certain individuals alone, is evidently abnormal ; and
as it chiefly affects exotic plants, or indigenous plants cul-
tivated in pots, we may attribute it to some change in
the conditions of life, acting on the plants themselves
or on their parents. The self-impotent Passiflora alata,
which recovered its self-fertility after having been graft-
ed on a distinct stock, shows how small a change is suffi-
cient to act powerfully on the reproductive system. The
possibility of a plant becoming under culture self-impotent
is interesting as throwing light on the occurrence of this
same condition in natural species. A cultivated plant
in this state generally remains so during its whole life ;
and from this fact we may infer that the state is proba-
bly congenital.

Kolreuter, however, has described some plants of
Verbascum which varied in this respect even during the
same season. As in all the normal cases, and in many,
probably in most, of the abnormal cases, any two self-
impotent plants can reciprocally fertilize each other, we
may infer that a very slight difference in the nature of
their sexual elements, suffices to give fertility ; but in
other instances, as with some Passifloras and the hybrid
Gladioli, a greater degree of differentiation appears to be

Chap. XVII CONCLUSION. 1 75

necessary, for with these plants fertility is gained only
by the union of distinct species, or of hybrids of distinct
parentage. These facts all point to the same general
conclusion, namely, that good is derived from a cross
between individuals, which either innately, or from expo-
sure to dissimilar conditions, have come to differ in sexual
constitution.

Exotic animals confined in menageries are sometimes
in nearly the same state as the above-described self-
impotent plants; for, as we shall see in the following
chapter, certain monkeys, the larger carnivora, several
finches, geese, and pheasants, cross together, quite as
freely as, or even more freely than, the individuals of the
same species breed together. Cases will, also, be given
of sexual incompatibility between certain male and fe-
male domesticated animals, which, nevertheless, are fer-
tile when matched with any other individual of the same
kind.

In the early part of this chapter it was shown that the
crossing of distinct forms, whether closely or distantly
allied, gives increased size and constitutional vigor, and,
except in the case of crossed species, increased fertility,
to the offspring. The evidence rests on the universal
testimony of breeders (for it should be observed that I
am not here speaking of the evil results of close inter-
breeding), and is practically exemplified in the higher
value of cross-bred animals for immediate consumption.
The good results of crossing have also been demon-
strated, in the case of some animals and of numerous
plants, by actual weight and measurement. Although
animals of pure blood will obviously be deteriorate* 1
by crossing, as far as their characteristic qualities are
concerned, there seems to be no exception to the rule
that advantages of the kind just mentioned are thus
gained, even when there has not been any previous close
interbreeding. The rule applies to all animals, even to'
cattle and sheep, which can long resist breeding in-and-in

176 GOOD FROM CEOSSING. Chap. XVIL

between the nearest blood-relations. It applies to indi-
viduals of the same sub-variety but of distinct families, to
varieties or races, to sub-species, as well as to quite dis-
tinct species.

In this latter case, however, whilst size, vigor, pre-
cocity, and hardiness are, with rare exceptions, gained,
fertility, in a greater or less degree, is lost ; but the
gain cannot be exclusively attributed to the principle
of compensation ; for there is no close parallelism be-
tween the increased size and vigor of the offspring and
their sterility. Moreover it has been clearly proved that
mongrels which are perfectly fertile gain these same ad-
vantages as Avell as sterile hybrids.

The evil consequences of long-continued close inter-
breeding are not so easily recognised as the good effects
from crossing, for the deterioration is gradual. Never-
theless it is the general opinion of those who have had
most experience, especially with animals which propagate
quickly, that evil does inevitably follow sooner or later,
but at different rates with different animals. ~No doubt
a false belief may widely prevail like a superstition ; yet
it is difficult to suppose that so many acute and original
observers have all been deceived at the expense of much
cost and trouble. A male animal may sometimes be
paired with his daughter, granddaughter, and so on,
even for seven generations, without any manifest bad
result ; but the experiment has never been tried of
matching brothers and sisters, which is considered the
closest form of interbreeding, for an equal number of
generations. There is good reason to believe that by
keeping the members of the same family in distinct bo-
dies, especially if exposed to somewhat different condi- •
tions of life, and by occasionally crossing these families,
the evil results may be much diminished, or quite eli-
minated. These results are loss of constitutional vigor,
size, and fertility ; but there is no necessary deteriora-
tion in the general form of the body, or in other good
qualities. We have seen that with pigs first-rate ani-

oup. xvn. CONCLUSION 177

mals have been produced after long-continued close inter-
breeding, though they had become extremely infertile
when paired with their near relations. The loss of
fertility, when it occurs, seems never to be absolute,
but only relative to animals of the same blood ; so that
this sterility is to a certain extent analogous with that
of self-impotent plants which cannot be fertilised by
their own pollen, but are perfectly fertile with pollen of
any other plant of the same species. The fact of infer-
tility of this peculiar nature being one of the results of
long-continued interbreeding, shows that interbreeding
does not act merely by combining and augmenting va-
rious morbid tendencies common to both parents ; for
animals with such tendencies, if not at the time actually
ill, can generally propagate their kind. Although off-
spring descended from the nearest blood-relations are not
necessarily deteriorated in structure, yet some authors 78
believe that they are eminently liable to malformations ;
and this is not improbable, as everything which lessens
the vital powers acts in this manner. Instances of this
kind have been recorded in the case of pigs, bloodhounds,
and some other animals.

Finally, when we consider the various facts now given
which plainly show that good follows from crossing, and
less plainly that evil follows from close interbreeding,
and when we bear in mind that throughout the whole
organic world elaborate provision has been made for the
occasional union of distinct individuals, the existence of
a great law of nature is, if not proved, at least rendered
in the highest degree probable ; namely, that the crossing
of animals and plants which are not closely related to
each other is highly beneficial or even necessary, and
that interbreeding prolonged during many generations is
highly injurious.

T8 This Is the conclusion cf Prof. some curious evidence on half the cases

Devay, ' Du Danger des Mariages Con- of a peculiar form of blindness occur-

sang.,' 1S62, p. 9T. Virchow quotes, in ring in the offspring from near relations,
the ' Deutsche Jahrbucher,' 1S63, 9. 354,

178 ON THE GOOD DERIVED Chap. XVEi.

CHAPTER XVIII.

ON THE ADVANTAGES AND DISADVANTAGES OF CHANG-
ED 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 — SEX-
UAL 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 SEED-
LESS FRUIT.

On the Good derived from slight Changes in the Condi-
tions of Life. — In considering whether any facts were
known which might throw light on the conclusion arrived
at in the last chapter, namely, that benefits ensue from
crossing, and that it is a law of nature that all organic
beings should occasionally cross, it appeared to me prob-
able that the good derived from slight changes in the con-
ditions of life, from being an analogous phenomenon, might
serve this purpose*. No two individuals, and still less no
two varieties, are absolutely alike in constitution and
structure ; and when the germ of one is fertilised by the
male element of another, we may believe that it is acted
on in a somewhat similar manner as an individual when

Chap. XVlll. FKOM CHANGED CONDITIONS. 179

exposed to slightly changed conditions. Now, every one
must have observed the remarkable influence on convales-
cents of a change of residence, and no medical man doubts
the truth of this fact. Small farmers who hold but little
land are convinced that their cattle derive great benefit
from a change of pasture. In the case of plants, the evi-
dence is strong that a great advantage is derived from
exchanging seeds, tubers, bulbs, and cuttings from one
soil or place to another as different as possible.

The belief that plants are thus benefited, whether or not well
founded, has been firmly maintained from the time of Columella,
who wrote shortly after the Christian era, to the present day; and
it now prevails in England, France, and Germany.1 A sagacious
observer, Bradley, writing in 1724,2 says, " When we once become
" Masters of a good Sort of Seed, we should at least put it into Two
" or Three Hands, where the Soils and Situations are as different as
" possible ; and every Year the Parties should change with one
" another ; by which Means, I find the Goodness of the Seed will be
" maintained for several Years. For Want of this Use many Farni-
" ers have failed in their Crops and been great Losers." He then
gives his own practical experience on this head. A modern writer 3
asserts, " Nothing can be more clearly established in agriculture
" than that the continual growth of any one variety in the same
" district makes it liable to deterioration either in quality or quan-
" tity." Another writer states that he sowed close together in the
same field two lots of wheat-seed, the product of the same original
stock, one of which had been grown on the same land, and the other
at a distance, and the difference in flavour of the crop from the latter
seed was remarkable. A gentleman in Surrey who has long made
it his business to raise wheat to sell for seed, and who has constantly
realised in the market higher prices than others, assures me that he
finds it indispensable continually to change his seed ; and that for
this purpose he keeps two farms differing much in soil and elevation.

1 For England, see below. For vol. iii. p. 58.

Germany, see Metzger, ' Getreidearten,' 3 ' Gardener's Chronicle and Agricult.

1S41, s. (8. For France, Loiseleur-Des- Gazette,' 1S53, p. 247 ; and for the

longchamps (' Consid. sur les Cereales,' second statement, idem, 1S50, p. 702.

1S43, p. 200) gives numerous references On this same subject, see also Rev. D.

on this subject. For Southern France, Walker's ' Prize Essay of Highland

see Godron, 'Florula Juvenalis,' 1654, Agricult. Soc.,' vol. ii. p. 200. Also

p. -'-: Marshall's ' Minutes of Agriculture.'

8 ' A general Treatise of Husbandry,' November, 1775.

180 OlST THE GOOD DERIVED Chap. XVIII.

With respect to the tubers of the potato, I find that at the present
day the practice of exchanging sets is almost everywhere followed.
The great growers of potatoes in Lancashire formerly used to get
tubers from Scotland, but they found that " a change from the moss-
lands, and vice versa, was generally sufficient." In former times in
France the crop of potatoes in theVosges had become reduced in the
course of fifty or sixty years in the proportion from 120-150 to 30-40
bushels ; and the famous Oberlin attributed the surprising good
which he effected in large part to changing the sets.4

A well-known practical gardener, Mr. Robson 5 positively states
that he has himself witnessed decided advantage from obtaining
bulbs of the onion, tubers of the potato, and various seeds, all of the
same kind, from different soils and distant parts of England. He
further states that with plants propagated by cuttings, as with the
Pelargonium, and especially the Dahlia, manifest advantage is
derived from getting plants of the same variety, which have been
cultivated in another place ; or, " where the extent of the place
" allows, to take cuttings from one description of soil to plant on
" another, so as to afford the change that seems so necessary to the
" well-being of the plants." He maintains that after a time an
exchange of this nature is " forced on the grower, whether he be pre-
" pared for it or not." Similar remarks have been made by another
excellent gardener, Mr. Fish, namely, that cuttings of the same
variety of Calceolaria, which he obtained from a neighbour, " showed
"much greater vigour than some of his own that were treated in
" exactly the same manner," and he attributed this solely to his own
plants having become " to a certain extent worn out or tired of their
" quarters." Something of this kind apparently occurs in grafting
and budding fruit-trees ; for, according to Mr. Abbey, grafts or buds
generally take on a distinct variety or even species, or on a stock
previously grafted, with greater facility than on stocks raised from
6eeds of the variety which is to be grafted ; and he believes this
cannot be altogether explained by the stocks in question being bet-
ter adapted to the soil and climate of the place. It should, however,
be added, that varieties grafted or budded on very distinct kinds,
though they may take more readily and grow at first more vigor-
ously than when grafted on closely allied stocks, afterwards often
become unhealthy.

4 'Oberlin's 'Memoirs,' Eng. translat., merits, see 'Journal of Horticulture,'

p. 73. For Lancashire, see Marshall's Feb. 18, 1S66, p. 121. For Mr. Abbey's

' Review of Reports,' 1S0S, p. 295. remarks on grafting, &c, idem, July IS,

» ' Cottage Gardener,' 1856, p. 186. 1S65, p. 44.
For Mr. Robson's subsequent state-

Chap. XYIII. FROM CHANGED CONDITIONS. 181

I have studied M. Tessier's careful and elaborate experiments,6
made to disprove the common belief that good is derived from a
change of seed ; and he certainly shows that the same seed may with
care be cultivated on the same farm (it is not stated whether on
exactly the same soil) for ten consecutive years without loss. An-
other excellent observer, Colonel Le Couteur,1 has come to the same
conclusion ; but then he expressly adds, if the same seed be used,
" that which is grown on land manured from the mixen one year
" becomes seed for land prepared with lime, and that again becomes
" seed for land dressed with ashes, then for land dressed with mixed
" manure, and so on." But this in effect is a systematic exchange of
seed, within the limits of the same farm.

On the whole the belief, which has long been held by
many skilful cultivators, that good follows from exchang-
ing seed, tubers, &c, seems to be fairly well founded.
Considering the small size of most seeds, it seems hardly
credible that the advantage thus derived can be due to
the seeds obtaining in one soil some chemical element
deficient in the other soil. As plants after once germi-
nating naturally become fixed to the same spot, it might
have been anticipated that they would show the good
effects of a change more plainly than animals, which con-
tinually wander about ; and this apparently is the case.
Life depending on, or consisting in, an incessant play of
the most complex forces, it would appear that their action
is in some way stimulated by slight changes in the cir-
cumstances to which each organism is exposed. All
forces throughout nature, as Mr. Herbert Spencer 8 re-
marks, tend towards an equilibrium, and for the life ot
each being it is necessary that this tendency should be
checked. If these views and the foregoing facts can be
trusted, they probably throw light, on the one hand, on

8 ' Mem. de l'Acad. des Sciences,' 1790, from slight changes in the conditions of

p. 209. " life and from cross-breeding, #nd of the

7 ' On the Varieties of Wheat,' p. 52. evil effects from great changes in the

8 Mr. Spencer has fully and ably dis- conditions an.l from crossing widely dis-
cussed this whole subject in his ' Princi- tinct forms, as a series of facts "connect-
ples of Biology,' 18C4, vol. ii.-ch. x. In ed together by some common but un-
the first edition of my ' Origin of Species,' known bond, which is essentially related
1S59, p. 267, I spoke of the good effects to the principle of life."

182 STERILITY FROM Chap. XVIII.

the good effects of crossing the breed, for the germ will
be thus slightly modified or acted on by new forces ; and
on the other hand, on the evil effects of close interbreed-
ing prolonged during many generations, during which the
germ will be acted on by a male having almost identi-
cally the same constitution.

Sterility from changed Conditions of Life.

I will now attempt to show that animals and plants,
when removed from their natural conditions, are often
rendered in some degree infertile or completely barren ;
and this occurs even when the conditions have not been
greatly changed. This conclusion is not necessarily op-
posed to that at which we have just arrived, namely, that
lesser changes of other kinds are advantageous to organic
beings. Our present subject is of some importance, from
having an intimate connexion with the causes of varia-
bility. Indirectly it perhaps bears on the sterility of
species when crossed : for as, on the one hand, slight
changes in the conditions of life are favourable to plants
and animals, and the crossing of varieties adds to the size,
vigour, and fertility of their offspring ; so, on the other
hand, certain other changes in the conditions of life cause
sterility ; and as this likewise ensues from crossing much-
modified forms or species, we have a parallel and double
series of facts, which apparently stand in close relation to
each other.

It is notorious that many animals, though perfectly
tamed, refuse to breed in captivity. Isidore Geoffroy St.
Hilaire 9 consequently has drawn a broad distinction be-
tween tamed animals which will not breed under captiv-
ity, and, truly domesticated animals which breed fseely —
generally more freely, as shown in the sixteenth chapter,
than in a state of nature. It is possible and generally

'Essais de Zoologie Generate,' 1841, p. 256.

Chap. XVIIL CHANGED CONDITIONS. 183

easy to tamo most animals ; but experience lias shown
that it is difficult to get them to breed regularly, or even
at all. I shall discuss this subject in detail ; but will give
only those cases which seem most illustrative. My mate-
rials are derived from notices scattered through various
works, and especially from a Report, drawn up for me by
the kindness of the officers of the Zoological Society of
London, which has especial value, as it records all the
cases, during nine years from 183S-46, in which the ani-
mals were seen to couple but produced no offspring, as
well as the cases in which they never, as far as known,
coupled. This MS. Report I have corrected by the
annual Reports subsequently published. Many facts are
given on the breeding of the animals in that magnificent
work, ' Gleanings from the Menageries of Knowsley Hall,'
by Dr. Gray. I made, also, particular inquiries from the
experienced keeper of the birds in the old Surrey Zoolo-
gical Gardens. I should premise that a slight change in
the treatment of animals sometimes makes a great differ-
ence in their fertility ; and it is probable that the results
observed in different menageries would differ. Indeed
some animals in our Zoological Gardens have become
more productive since the year 1 846. It is, also, manifest
from F. Cuvier's account of the Jardin des Plantes,10 that
the animals formerly bred much less freely thei*e than
with us ; for instance, in the Duck tribe, which is highly
p/olific, only one species had at that period produced
young.

The most remarkable cases, however, are afforded by animals
kept in their native country, which, though perfectly tamed, quite
healthy, and allowed some freedom, are absolutely incapable of
breeding. Reng<rer,uwhoin Paraguay particularly attended to this
subject, specifies six qiiadrupeds in this condition ; and he mentions
two or three others which most rarely breed. Mr. Bates, in his ad-

10 Du nut, ' Annales du Museum,' s. 49, 106, US, 124, 201, 208, 249, 265,
1807, torn. ix. p. 120. D27.

" ' Siugetbiere von Paraguay,1 1830,

184 STERILITY FROM Chap. XVIII.

mirable work on the Amazons, strongly insists on similar cases ; 12
and he remarks, that the fact of thoroughly tamed native mam-
mals and birds not breeding when kept by the Indians, cannot be
wholly accounted for by their negligence or indifference, for the
turkey is valued by them, and the fowl has been adopted by the
remotest tribes. In almost every part of the world — for instance, in
the interior of Africa, and in several of the Polynesian islands — the
natives are extremely fond of taming the indigenous quadrupeds
and birds ; but they rarely or never succeed in getting them to
breed.

The most notorious case of an animal not breeding in captivity is
that of the elephant. Elephants are kept in large numbers in their
native Indian home, live to old age, and are vigorous enough for the
severest labour ; yet, with one or two exceptions, they have never
been known even to couple, though both males and females have
their proper periodical seasons. If, however, we proceed a little
eastward to Ava, we hear from Mr. Crawfurd 13 that their " breeding
in the domestic state, or at least in the half-domestic state in which
the female elephants are generally kept, is of every-day occurrence ;"
and Mr. Crawfurd informs me that he believes that the difference
must be attributed solely to the females being allowed to roam the
forests with some degree of freedom. The captive rhinoceros, on
the other hand, seems from Bishop Heber's account I4 to breed in
India far more readily than the elephant. Four wild species of the
horse genus have bred in Europe, though here exposed to a great
change in their natural habits of life ; but the species have gene-
rally been crossed one with another. Most of the members of the pig.
family breed readily in our menageries : even the Red River hog
(Potamoehcerits penicillatus), from the sweltering plains of West
Africa, has bred twice in the Zoological Gardens. Here also the
Peccary (Dicotyles torquatus) has bred several times ; but another
species, the D. labiatus, though rendered so tame as to be half-
domesticated, breeds so rarely in its native country of Paraguay,
that according to Rengger 16 the fact requires confirmation. Mr.
Bates remarks that the tapir, though often kept tame in Amazonia
by the Indians, never breeds.

Ruminants generally breed quite freely in England, though
brought from widely different climates, as may be seen in the An-
nual Reports of the Zoological Gardens, and in the Gleanings from
Lord Derby's menagerie.

12 ' The Naturalist on the Amazons,' i. p. 534.

B63, vol. i pp. 99, 193 ; vol. ii. p. 1 13. »* « Journal,1 vol. i. p. 213.

13 ' Embassy to the Court of Ava,' vol. l6 ' Saugethiere,' s. 827.

Chap. XVIII. CHANGED CONDITIONS. 185

The Carnivora, with the exception of the Plantigrade division,
generally breed (though with capricious exceptions) almost as freely
as ruminants. Many species of Felidse have bred in various mena-
geries, although imported from various climates and closely confined.
Mr. Bartlett, the present superintendent of the Zoological Gardens,18
remarks that the lion appears to breed more frequently and to bring
forth more young at a birth than any other species of the family.
He adds that the tiger has rarely bred ; " but there are several well-
authenticated instances of the female tiger breeding with the lion."
Strange as the fact may appear, many animals under confinement
unite with distinct species and produce hybrids quite as freely as, or
even more freely than, with their own species. On inquiring from
Dr. Falconer and others, it appears that the tiger when confined in
India does not breed, though it has been known to couple. The
cheetah (Felis jubata) has never been known by Mr. Bartlett to breed
in England, but it has brod at Frankfort ; nor does it breed in India,
where it is kept in large numbers for hunting ; but no pains would
be taken to make them breed, as only those animals which have
hunted for themselves in a state of nature are serviceable and worth
training.17 According to Rengger, two species of wild cats in Para-
guay, though thoroughly tamed, have never bred. Although so
many of the Felidre breed readily in the Zoological Gardens, yet
conception by no means always follows union : in the nine-year
Report, various species are specified which were observed to couple
seventy-three times, and. no doubt this must have passed many
times unnoticed ; yet from the seventy-three unions only fifteen
births ensued. The Carnivora in the Zoological Gardens were for-
merly less freely exposed to the air and cold than at present, and this
change of treatment, as I was assured by the former superinten-
dent, Mr. Miller, greatly increased their fertility. Mr. Bartlett,
and there cannot be a more capable judge, says, " it is remarkable
" that lion? breed more freely in travelling collections than in the
" Zoological Gardens ; probably the constant excitement and irrita-
" tion produced by moving from place to place, or change of air,
" may have considerable influence in the matter."

Many members of the Dog family breed readily when confined.
The Dhole is one of the most untamcable animals in India, yet a
pair kept there by Dr. Falconer produced young. Foxes, on the
other hand, rarely breed, and I have never heard of such an occur-
rence with the European fox : the silver fox of North America
(Cams argentatus), however, has bred several times in the Zoologi-

18 On the Breeding of the larger Felidae, 1T Sleeruan's ' Rambles in India,' vol.

1 Proc. Zoolog. Soc.,' 1361, p. 140. ii. p. 10.

186 STERILITY FROM Chap. XVIII.

cal Gardens. Even the otter has bred there. Every one knows
how readily the semi-domesticated ferret breeds, though shut up in
miserably small cages ; but other species of Viverra and Paradox-
urus absolutely refuse to breod in the Zoological Gardens. The
Genetta has bred both heTe and in the Jardin des Plantes, and pro-
duced hybrids. The Herpeatex faaciatua has likewise bred ; but I
was formerly assured that the H. griseus, though many were kept
in the Gardens, never bred.

The Plantigrade Carnivora breed under confinement much less
freely, without our being able to assign any reason, than other
members of the group-. In the nine-year Report it is stated
that the bears had been seen in the Zoological Gardens to couple
freely, but previously to 1848 had most rarely conceived. In the
Reports published since this date three species have produced young
(hybrids in one case), and, wonderful to relate, the white Polar bear
has produced young. The badger (Mde& ta.vus) has bred several
times in the Gardens ; but I have not heard of this occurring else-
where in England, and the event must be very rare, for an instance
in Germany has been thought worth recording.18 In Paraguay the
native Xasua, though kept in pairs during many years and per-
fectly tamed, has never been known, according to Rengger, to breed
or show any sexual passion ; nor, as I hear from Mr. Bates, does
this animal, or the Cercoleptes, breed in the region of the Amazons.
Two other plantigrade genera, Procyon and Gulo, though often
kept tame in Paraguay, never breed there. In the Zoological Gar-
dens species of Nasua and Procyon have been seen to couple ; but
they did not produce young.

As domesticated rabbits, guinea-pigs, and white mice breed so
abundantly when closely confined under various climates, it might
have been thought that most other members of the Rodent order
would have bred in captivity, but this is not the case. It deserves
notice, as showing how the capacity to breed sometimes goes by af-
finity, that the one native rodent of Paraguay, which there breeds
freely and has yielded successive generations, is the Cavia aperea ;
and this animal is so closely allied to the guinea-pig, that it has been
erroneously thought to be the parent-form.19 In the Zoological
Gardens, some rodents have coupled, but have never produced
young ; some have neither coupled nor bred ; but a few have bred,
as the porcupine more than once, the Barbary mouse, lemming,
chinchilla, and the agouti {Dazyprocta aguti), several times. 'This

18 Wiegmann's 'Archif fur Natur- On the parentage of the guinea-pig, see
gesch ,' 1S37, s. 162. also Isid. Geoffroy St. Hilaire, ' Hist.

19 Rengger, ' Saugethiere,' Ac, s. 276. Nat. Gen.'

Chap. will. CHANGED CONDITIONS. 187

latter animal has also produced young in Paraguay, though they
were born dead and ill-formed ; but. in Amazonia, according to Mr.
Bates, it never breeds, though often kept tame about the houses.
N(»r does the paca {GoUogenya paea) breed there. The common hare
when confined has, I believe, never bred in Europe ;2° though, ac-
cording to a recent statement, it has crossed with the rabbit. I have
never heard of the dormouse breeding in confinement. But squir-
rels offer a more curious case : with one exception, no species has
evrr bred in the Zoological Gardens, yet as many as fourteen indi-
viduals of ft ])abnarum were kept together during several years.
The 8. cinerea has been seen to couple, but it did not produce
young ; nor has this species, when rendered extremely tame in its
native country, North America, been ever known to breed.21 At
Lord Derby's menagerie squirrels of many kinds were kept in num-
bers, but Mr. Thompson, the superintendent, told me that none had
ever bred there, or elsewhere as far as he knew. I have never heard
of the English squirrel breeding in confinement. But the species
which has bred more than once in the Zoological Gardens is the
one which perhaps might have been least expected, namely, the
flying sqiurrel (Sciuropterus volucella) : it has, also, bred several
times near Birmingham ; but the female never produced more than
two young at a birth, whereas in its native American home she
bears from three to six young.22

Monkeys, in the nine-year Report from the Zoological Gardens,
are stated to unite most freely, but during this period, though many
individuals were kept, there were only seven births. I have heard
of one American monkey alone, the Ouistiti, breeding in Europe.23
A Macacus, according to Flourens, bred in Paris ; and more than one
species of this genus has produced young in London, especially the
Macacus rhesus, which everywhere shows a special capacity to
breed under confinement. Hybrids have been produced both in
Paris and London from this same genus. The Arabian baboon, or
Cynocephalus hamadryrts™ and a Cercopithecus have bred in the
Zoological Gardens, and the latter species at the Duke of North-

20 Although the existence of the Lupo- ix., 1S36, p. 571; Audubon and Bach-

rides, as described by Dr. Broca (' Jour- man's ' Quadrupeds of North America,'

nal de Pliys.,' torn. ii. p. 870), Is now p. 221.

positively denied, yet Dr. Pigeaux ('An- 23 Flourens, 'De l'lnstinct,' &c, 1S45,

nals and Mag. of Nat. Hist.,' vol. xx., p. S3

18G7, p. 75) affirms that the hare, and ^See' Annual Reports Zoolog. Soc.,'

rabbit have produced hybrids. 1S55, 1853, 1363, 1SG4 ; 'Times' news-

' 21 'Quadrupeds of North America,' paper, Aug. 10th, 1S47; Flourens, 'De

by Audubon and Bachman, 1846, p. 263. l'lnstinct,1 p. 85.

22 Loudon's ' Mag. of Nat. Hist.,' vol.

188 STERILITY FROM Chap. XVIII.

umberland's. Several members of the family of Lemurs have pro-
duced hybrids in the Zoological Gardens. It is much more remark-
able that monkeys very rarely breed when confined in their native
country ; thus the Cay (Cebus azarce) is frequently and completely
tamed in Paraguay, but Rengger 2B says that it breeds so rarely, that
he never saw more than two females which had produced young. A
similar observation has been made with respect to the monkeys
which are frequently tamed by the aborigines in Brazil.36 In the
region of the Amazons, these animals are so often kept in a tame
state, that M. Bates in walking through the streets of Para counted
thirteen species ; but, as he asserts, they have never been known to
breed in captivity.27

Birds.

Birds offer in some respects better evidence than quadrupeds,
from their breeding more rapidly and being kept in greater nam •
bers. We have seen that carniverous animals are more fertile
under confinement than most other mammals. The reverse holds
good with carniverous birds. It is said 2M that as many as eighteen
species have been used in Europe for hawking, and several others
in Persia and India ; 2* they have been kept in their native country
in the finest condition, and have been flown during six, eight, or
nine years ; 30 yet there is no record of their having ever produced
young. As these birds were formerly caught, whilst young, at
great expense, being imported from Iceland, Norway, and Swe-
den, there can be little doubt that, if possible, they would have
been propagated. In the Jardin des Plantes, no bird of prey has
been known to couple.31 No hawk, vulture, or owl has ever pro-
duced fertile eggs in the Zoological Gardens, or in the old Surrey
Gardens, with the exception, in the former place on one occasion, of
a condor and a kite, (Milvus niger). Yet several species, namely, the
Aquila fusca, Haliostus leucoceplialus, Falco tinnunculus, F. subbtu
teo, and Buteo vulgaris, have been seen to couple in the Zoological
Gardens. Mr. M orris 32 mentions as a unique fact that a kestrel
{Falco tinnunculus) bred in an aviary. The one kind of owl which
has been known to couple in the Zoological Gardens was the Eagle

25 ' Saugethiere,' &c, s. 34, 49. hawking in Scinde.

26 Art. Brazil, ' Penny Cyclop.,' p 363. 30 Loudon's 'Mag. of Nat. Hist.,' vol.

27 ' The Naturalist on the River Ama- vi., 1833, p. 110.

zon,' vol. i. p. 99. 31 F. Cuvier, 'Annal. du Museum,' torn.

28 ' Encyclop. of Rural Sports,' p. G91. li. p. 128.

29 According to Sir A. Burnes ('Cabool,' 32 ' The Zoologist,' vol. vii.-viii., 1849-
&C, p. 51), eight species are used for 50, p. 2648.

Chap. XVIII. CHANGED CONDITIONS. 1S9

Owl (Bubo mcuamua); and tins species shows a special inclination
to breed* in captivity ; for a pair at Arundel Castle, kept more nearly
in a state of nature " than ever fell to the lot of an animal deprived
of its liberty " 33 actually reared their young. Mr. Gurney has giv-
en another instance of this same owl breeding in confinement ;
and he records the case of a second species of owl, the Strix pas-
se rina, breeding in captivity.34

Of the smaller graminivorous birds, many kinds have been kept
tame in their native countries, and have lived long ; yet, as the
highest authority on cage birds 35 remarks, their propagation is
" uncommonly difficult." The canary-bird shows that there is no in-
herent difficulty in these birds breeding freely in confinement ; and
Audubon says 36 that the Fringilla (Spiza) ciris of North America
breeds as perfectly as the canary. The difficulty with the many
finches which have been kept in confinement is all the more remark-
able as more than a dozen species could be named which have
yielded hybrids with the canary ; but hardly any of these, with the
exception of the siskin (Friwjilla spiaus), have reproduced their
own kind. Even the bullfinch (Loxia pyrrhula) has bred as fre-
quently with the canary, though belonging to a distinct genus, as
with its own species.31 With respect to the skylark (Alauda arvcn-
ri»), I have heard of birds living for seven years in an aviary, which
never produced young; and a great London bird-fancier assured
me that he had never known an instance of their breeding ; never-
theless one case has been recorded.38 In the nine-year Report from
the Zoological Society, twenty-four incessorial species are enume-
rated which had not bred, and of these only four were known to
have coupled.

Parrots are singularly long-lived birds ; and Humboldt men-
tions the curious fact of a parrot in South America, which spoke
the language of an extinct Indian tribe, so that this bird pre-
served the sole relic of a lost language. Even in this country
there is reason to believe 39 that parrots have lived to the age of
nearly one hundred years; yet, though many have been kept in
Europe, they breed so rarely that the event has been thought worth

33 Knox ' Ornithological Rambles in gist,' vol. l.-ii., 1848-45, p. 453. For the

Sussex,' p. 91. siskin breeding, vol. iii.-iv., 1S45-4G, p.

31 'The Zoologist,' vol. vii.-viii., 1849- 1075. Bechstein, 'Stubenvogel,' s. 13;>,

5.1, p. '2j0G; vol. ix.-x., 1S51-2, p. 3207. speaks of bullfinches making nest-, but

33 Bechstein, ' Naturgesch. der Stubea- rarely producing young.

vogel,' 1810, s. 20. 3<* Zarrell'B ' Hist. British Birds,' 1S39,

36 ' Ornithological Biography,' vol. V. vol. i. p. 412.

p. 517. 39 Loudon's ' Mag. of Nat. History,'

87 A case is recorded in ' The Zoolo- vol. ix., 1S36, p. 847.

190 STERILITY FROM Chap. XVIII.

recording in the gravest publications.40 According to Bechstein 41
the African Psittacus e'ritliacus breeds oftener than any other spe-
cies : the P. macoa occasionally lays fertile eggs, but rarely succeeds
in hatching them ; this bird, however, has the instinct of incuba-
tion sometimes so strongly developed, that it will hatch the eggs
of fowls or pigeons. In the Zoological Gardens and in the old Sur-
rey Gardens some few species have coupled, but, with the exception
of three species of parrakeets, none have bred. It is a much more
remarkable fact that in Guiana parrots of two kinds, as I am in-
formed by Sir R. Schomburgk, are often taken from the nests by
the Indians and reared in large numbers ; they are so tame that
they fly freely about the houses, and come when called to be fed,
like pigeons ; yet he has never heard of a single instance of their
breeding.42 In Jamaica, a resident naturalist, Mr. R. Hill,43 says,
" no birds more readily submit to human dependence than the par-
" rot-tribe, but no instance of a parrot breeding in this tame life
" has been known yet." Mr. Hill specifies a number of other native
birds kept tame in the West Indies, which never breed in this state.

The great pigeon family offers a striking contrast with parrots :
in the nine-year Report thirteen species are recorded as having bred,
and, what is more noticeable, only two were seen to couple without
any result. Since the above date every annual Report gives many
cases of various pigeons breeding. The two magnificent crowned
pigeons (Goura coronata and Victoria) produced hybrids ; never-
theless, of the former species more than a dozen birds were kept, as
I am informed, by Mr. Crawfurd, in a park at Penang, under a per-
fectly well-adapted climate, but never once bred. The Columba
migvatoria in its native country, North America, invariably lays
two eggs, but in Lord Derby's menagerie never more than one.
The same fact has been observed with the C. leucocephala.u

Gallinaceous birds of many genera likewise show an eminent
capacity for breeding under captivity. This is particularly the case
with pheasants ; yet our English species seldom lays more than ten
eggs in confinement ; whilst from eighteen to twenty is the usual
number in the wild state.45 With the Gallinaceae, as with all other

40 'Memoiresdu Museum d'Hist. Nat.,' nous to Guiana, none are found to pro-
torn, x. p. 314 : five cases of parrots breed- pagate among the Indians ; yet the com-
ing in France are here recorded. See, mon fowl is reared in abundance through-
also, ' Report Brit. Assoc. Zoolog.,' 1S43. out the country."

41 ' Stubenvogel.' s. 105, S3. « ' A Week at Port Royal,' 1355, p. 7.

42 Dr. Hancock remarks (' Charles- 44 Audubon, ' American Ornithology,'
worth's Mag. of Nat. Hist.,' vol. ii., 1S3S vol. v. pp. 552, 55T.

p. 492), " it is singular that, amongst the 43 Moubray on Poultry, 7th edit., p.

numerous useful birds that are indige- 133.

Chap: XVIII. CHANGED CONDITIONS. 191

orders, there are marked and inexplicable exceptions in regard to
the fertility of certain species and genera under confinement. Al-
though many trials have been made with the common partridge, it
has rarely bred, even when reared in large aviaries ; and the hen
will never hatch her own eggs.46 The American tribe of Guans or
Cracida? are tamed with remarkable ease, but are very shy breeders in
this country ;47 but with care various species were formerly made to
breed rather freely in Holland.48 Birds of this tribe are often kept in
a perfectly tamed condition in their native country by the Indians,
but they never breed.49 It might have been expected that grouse
from their habits of life would not have bred in captivity, more
especially as they are said soon to languish and die.6* But many
cases are recorded of their breeding : the capercailzie {Tetrao vro-
gaUus) has bred in the Zoological Garden ; it breeds without much
difficulty when confined in Norway, and in Russia five successive
generations have been reared : Tetrao tetrix has likewise bred in
Norway ; T. Seotieus in Ireland ; T. umbellus at Lord Derby's; and
T. cupido in North America.

It is scarcely possible to imagine a greater change in habits than
that which the members of the ostrich family must suffer, when
cooped up in small enclosures under a temperate climate, after freely
roaming over desert and tropical plains or entangled forests. Yet
almost all the kinds, even the mooruk (Casnarius Bennettii) from
New Ireland, has frequently produced young in the various Euro-
pean menageries. The African ostrich, though perfectly healthy
and bving long in the South of France, never lays more than from
twelve to fifteen eggs, though in its native country it lays from
twenty-five to thirty.61 Here we have another instance of fertility
impaired, but not lost, under confinement, as with the flying squirrel,
the hen-pheasant, and two species of American pigeons.

Most Waders can be tamed, as the Rev. E. S. Dixon informs me,

48 Temminck, ' Hist. Nat. Gen. des 49 Bates, ' The Naturalist on the Ama-

1'igeons,' &c, 1813, torn. Tii. pp. 2SS, zons,' vol. i. p. 193; vol. ii. p. 112.

882; 'Annals and Mag. of Nat. Hist.,' 60 Temminck, 'Hist. Nat. Gen.,' Ac,

vol. xii., IS*?, p. 453. Other species of torn. iii. p. 125. For Tetrao urogallti?,

partridge have occasionally bre.d ; as the see L. Lloyd, ' Field Sports of North of

red-legged (P. rubra), when kept in a Europe,' vol. i. pp. 2S7, 314; and 'Bull,

large court in France (see ' Journal de de la Soe. d'Acclimat.,' torn, vii., 18fi0, p.

Physifiue,' torn. xxv. p. 294), and in the 600. For T. Scoticus, Thompson, ' Nat.

ical Hardens in 1S56. Hist, of Ireland,' vol. ii., 1S50, p. 49. For

47 Rev. E. S. Dixon, ' The Dovecote,' T. cupido, ' Boston Journal of Nat.
1851, pp. 243-252. Hist,,' vol. iii. p. 199.

48 Temminck, 'Hist. Nat. Ge'n. des 61 Marcel de Serres, ' Annales des Sci.
Pigeons,' Jcc, torn. ii. pp. 450, 458 ; torn. Nat.,' 2nd series, ' Zoolog.,' torn. xiii. p.
IB. pp. 2, 13, 47. 175.

192 STERILITY FROM Chap. xvill.

with remarkable facility ; but several of them are short-lived under
confinement, so that their sterility in this state is not surprising.
The cranes breed more readily than other genera: Grits monti-
gresia has bred several times in Paris and in the Zoological Gar-
dens, as has G. cinerea at the latter place, and G. antigone at Cal-
cutta. Of other members of this great order, Tetraptcryx paradisea
has bred at Knowsley, a Porphyrio in Sicily, and the Gallinida
chloropus in the Zoological Gardens. On the other hand, several
birds belonging to this order will not breed in their native country,
Jamaica ; and the Psophia, though often kept by the Indians of
Guiana about their houses, "is seldom or never known to breed."52

No birds breed with such complete facility under confinement as
the members of the great Duck family ; yet, considering their aqua-
tic and wandering habits, and the nature of their food, this could
not have been anticipated. Even some time ago above two dozen
species had bred in the Zoological Gardens ; and M. Selys-Long-
champs has recorded the production of hybrids from forty -four differ-
ent members of the family ; and to these Professor Xewton has
added a few more cases.53 " There is not," says Mr. Dixon,54 " in the
wide world, a goose which is not in the strict sense of the word do-
mesticable ;" that is, capable of breeding under confinement ; but
this statement is probably too bold. The capacity to breed some-
times varies in individuals of the same species ; thus Audubon 5S
kept for more than eight years some wild geese (Anser Canadensis),
but they would not mate ; whilst other individuals of the same spe-
cies produced young during the second year. I know of but one in-
stance in the whole family of a species which absolutely refuses to
breed in captivity, namely, the Dendrorygna xiduata, although, ac-
cording to Sir R. Schomburgk,56 it is easily tamed, and is frequently
kept by the Indians of Guiana. Lastly, with respect to Gulls,
though many have been kept in the Zoological Gardens and in the
old Surrey Gardens, no instance was known before the year 1848 of
their coupling or breeding ; but since that period the herring gull
{Larus argentatus) has bred many times in tke Zoological Gardens
and at Knowsley.

There is reason to believe that insects are affected by confinement

62 Dr. Hancock, in ' Charlesworth's 63 Prof. Newton, in ' Proc. Zoolog.

Mag. of Nat. Hist.' vol. ii., 183% p. 491 ; Soc.,' 1S60, p. 336.

R. Hill, ' A Week at Port Royal,' p. S ; " ' The Dovecote and Aviary,' p. 42S.

'Guide to the Zoological Gardens,' by 5S 'Ornithological Biography,' vol. iii.

P. L. Sclater, 1S59, pp. 11, 12; 'The p. 9.

Knowsley Menagerie,' by Dr. Gray,' 1S46, 58 ' Geograph. Journal,' vol. xiii.,

pi. xiv. ; E. Blyth. ' Report Asiatic Soc. 1S44, p. 32.
of Bengal,' May, 1855.

CnAr. Win. CHANGED CONDITIONS. 193

like the higher animals. It is well known that the Sphingidae
rarely breed when thus treated. An entomologist'" in Paris kept
twenty-five specimens of Saturnia pyri, but did not succeed in get-
ting a single fertile egg. A number of females of Orthotic munda
and of Mdmestra WUUa reared in confinement Avere unattractive to
the males/* Mr. Newport kept nearly a hundred individuals of two
species of Vanessa, but not one paired ; this, however, might have
been due to their habit of coupling on the wing.59 Mr. Atkinson
could never succeed in India in making the Tarroo silk-moth breed
in confinement.80 It appears that a number of moths, especially the
Sphingidae, when hatched in the autumn out of their proper season,
are completely barren ; but this latter case is still involved in some
obscurity.81

Independently of the fact of many animals under con-
finement not coupling, or, if they couple, not producing
young, there is evidence of another kind that their sexual
functions are thus disturbed. For many cases have been
recorded of the loss by male birds when confined of their
characteristic plumage. Thus the common linnet (Lino-
t<i caimaMna) when caged does not acquire the fine crim-
son colour on its breast, and one of the buntings (JEJnibe-
rizn passerina) loses the black on its head. A Pyrrlmla
and an Oriolus have been observed to assume the quiet
plumage of the hen-bird ; and the Falco albldns returned
to the dress of an earlier age.62 Mr. Thompson, the su-
perintendent of the Knowsley menagerie, informed me
that he had often observed analogous facts. The horns
of a male deer (Cervus Canadensis) during the voyage
from America were badly developed ; but subsequently
in Paris perfect horns were produced.

67 London's 'Mag. of Nat. Hist.,' vol. 5764; and Dr. Wallace, in ' Proc. Ento-

v.. 1882, p. 153. molog. Soc.,' June 4th, IsCO, p. 119.

59 'Zoologist,' vol9. v.-vi., 1847-48, p. «a Yarrell's 'British Birds.' vol. i. p.
1660. 506; Bechstein, ' StubenvoTet,' s. 186;

s» 'Transact. Entomolog. Soc.,' vol. ' Philosoph. Transact..' 1"7'2, p. '271.

lv., 1845, p. 60. Bronn ('Gescliichte der Natur.' Bund ii.

60 ' Transact. Linn. Soc.,' vol. vii. p. s. 96) has collected a number of ea=e-=.
4<». • For the case of the deer, see 'Penny

M 8et an interesting paper by Mr. Cyclop.,' vol. viii. p. 350.
Newman, in' the ' Zoologist,' 1S57, p.

194 STERILITY FROM Chap. XVIII.

When conception takes place under confinement, the
young are often born dead, or die soon, or are ill-formed.
This frequently occurs in the Zoological Gardens, and,
according to Ttengger, with native animals confined in
Paraguay. The mother's milk often fails. We may also
attribute to the disturbance of the sexual functions the
frequent occurrence of that monstrous instinct which leads
the mother to devour her own offspring, — a mysterious
case of perversion, as it at first appears.

Sufficient evidence has now been advanced to prove
that animals when first confined are eminently liable to
suffer in their reproductive systems. We feel at first na-
turally inclined to attribute the result to loss of health,
or at least to loss of vigour ; but this view can hardly be
admitted when we reflect how healthy, long-lived, and
vigorous many animals are under captivity, such as par-
rots, and hawks when used for hawking, chetahs when
used for hunting, and elephants. The reproductive or-
gans themselves are not diseased ; and the diseases, from
which animals in menageries usually perish, are not those
which in any way affect their fertility. No domestic
animal is more subject to disease than the sheep, yet it
is remarkably prolific. The failure of animals to breed
under confinement has been sometimes attributed exclu-
sively to a failure in their sexual instincts : this may oc-
casionally come into play, but there is no obvious reason
Avhy this instinct should be especially liable to be affected
with perfectly tamed animals, except indeed indirectly
through the reproductive system itself being disturbed.
Moreover, numerous cases have been given of various
animals which couple freely under confinement, but never
conceive ; or, if they conceive and produce young, these
are fewer in number than is natural to the species. In
the vegetable kingdom instinct of course can play no
part ; and we shall presently see that plants when remov-
ed from their natural conditions are affected in nearly
the same manner as animals. Change of climate cannot

Chap. XV1IL CHANGED CONDITIONS. 195

be the cause of the loss of fertility, for, whilst many ani-
mals imported into Europe from extremely different cli-
mates breed freely, many others when confined in their
native land are completely sterile. Change of food can-
not be the chief cause ; for ostriches, ducks, and many
other animals, which must have undergone a great
change in this respect, breed freely. Carnivorous birds
when confined are extremely sterile; whilst most carni-
vorous mammals, except plantigrades, are moderately
fertile. Nor can the amount of food be the cause ; for a
sufficient supply will certainly be given to valuable ani-
mals ; and there is no reason to suppose that much more
food would be given to'them, than to our choice domes-
tic productions which retain their full fertility. Lastly,
we may infer from the case of the elephant, chetah,
various hawks, and of many animals Avhich are allowed
to lead an almost free life in their native land, that want
of exercise is not the sole cause.

It would appear that any change in the habits of life,
whatever these habits may be, if great enough, tends to
affect in an inexplicable manner the powers of reproduc-
tion. The result depends more on the constitution of the
species than on the nature of the change ; for certain
whole groups are affected more than others ; but excep-
tions always occur, for some species in the most fertile
groups refuse to breed, and some in the most sterile
groups breed freely. Those animals which usually breed
freely under confinement, rarely breed, as I was assured,
in the Zoological Gardens, within a year or two after their
first importation. "When an animal which is generally
sterile under confinement happens to breed, the young
apparently do not inherit this power; for had this been
the case, various quadrupeds and birds, which are valuable
for exhibition, would have become common. Dr. Broca
even affirms 83 that many animals in the Jardin des Plantes,

M ' Journal de Physiologic,' torn. ii. p. 347.

196 STERILITY FROM Chap. XVIII.

after having produced young for three or four succes-
sive generations, become sterile ; but this may be the re-
sult of too close interbreeding. It is a remarkable circum-
stance that many mammals and birds have produced hy-
brids under confinement quite as readily as, or even more
readily than, they have procreated their own kind. Of
this fact many instances have been given ; °* and we are
thus reminded of those plants which when cultivated re-
fuse to be fertilised by their own pollen, but can easily
be fertilised by that of a distinct species. Finally, we
must conclude, limited as the conclusion is, that changed
conditions of life have an especial power of acting inju-
riously on the reproductive system. The whole case is
quite peculiar, for these organs, though not diseased, are
thus rendered incapable of performing their proper func-
tions, or perform them imperfectly.

Sterility of Domesticated Animals from changed conditions. — With
respect to domesticated animals, as their domestication mainly de-
pends on the accident of their breeding freely under captivity, we
ought not to expect that their reproductive system would be affected
by any moderate degree of change. Those orders of Quadrupeds
and birds, of which tlie wild species breed most readily in our me-
nageries, have afforded us the greatest number of domesticated pro-
ductions. Savages in most parts of the world are fond of taming
animals ; 63 and if any of these regularly produced young, and were
at the same time useful, they would be at once domesticated. If,
when their masters migrated into other countries, they were in ad-
dition found capable of withstanding various climates, they would
be still more valuable ; and it appears that the animals which breed
readily in captivity can generally withstand different climates. Some
few domesticated animals, such as the reindeer and camel, offer an
exception to this rule. Many of our domesticated animals can bear

64 For additional evidence on this sub- young antelope was brought to him. Mr.

ject, see F. Cuvier, in 'Annales du Mu- Galton informs me that the Damaras are

seum,' torn. xii. p. 119. likewise fond of keeping pets. The In-

86 Numerous instances could be given. dians of South America follow the same

Thus Livingstone (' Travels,' p. 217) habit. Capt. Wilkes states that the Po-

states that the King of the Barotse, an lynesians of the Samoan Islands tamed

inland tribe which never had any com- pigeons ; and the New Zealanders, as Mr.

munication with white men, was extreme- Mantell informs me, kept various kinds

ly fond of taming animals, and every of birds.

Chap, xviii. CHANGED CONDITIONS. 197

Avith undiminished fertility the most unnatural conditions ; for in-
stance, rabbits, guinea-pigs, and ferrets breed in miserably confined
hutches. Few European dogs of any kind withstand without de-
generation the climate of India; but as long as they survive, they
retain, as I hear from Dr. Falconer, their fertility ; so it is, accord-
ing to Dr. Daniell, with English dogs taken to Sierra Leone. The
fowl, a native of the hot jungles of India, becomes more fertile than
its parent-stock in every quarter of the world, until we advance as«
far north as Greenland and Northern Siberia, where this bird will
not breed. Both fowls and pigeons, which I received during the
autumn direct from Sierra Leone, were at once ready to couple.66
I have, also, seen pigeons breeding as freely as the common kinds
within a year after their importation from the Upper Nile. The
guinea-fowl, an aboriginal of the hot and dry deserts of Africa,
whilst living under our damp and cool climate, produces a large
supply of eggs.

Nevertheless, our domesticated animals under new conditions oc-
casionally show signs of lessened fertility. Eoulin asserts that in
the hot ralleys of the equatorial Cordillera sheep are not fully
fecund ; " and according to Lord Somerville,6" the merino-sheep
which he imported from Spain were not at first perfectly fertile. It
is said 69 that mares brought up on dry food in the stable, and turned
out to grass, do not at first breed. The peahen, as we have seen, is
said not to lay so many eggs in England as in India. It was long be-
fore the canary-bird was fully fertile, and even now first-rate breed-
ing birds are not common.70 In the hot and dry province of Delhi,
the eggs of the turkey, as I hear from Dr. Falconer, though placed
under a hen, are extremely liable to fail. According to Roulin,
geese taken within a recent period to the lofty plateau of Bogota, at
first laid seldom, and then only a few eggs ; of these scarcely a
fourth were hatched, and half the young birds died : in the second
generation they were more fertile ; and when Roulin wrote they
were becoming as fertile as our geese in Europe. In the Philippine
Archipelago the goose, it is asserted, will not breed or even lay
eggs.71 A more curious case is that of the fowl, which, according
to Roulin, when first introduced would not breed at Cusco in Boli-

66 For analogous cases with the fowl, des Sciences,' torn, vi., 1835, p. 347.

see Reaumur, ' Art de faire Eclorre,' &c, 68 Youatt on Sheep, p. 181.

1749, p. 243; and Col. Sykes, in 'Proc. 6<» J. Mills, ' Treatise on Cattle,' 1776,

Zoolog. Soc.,' 1S32, &c. With respect to p. 72.

the fowl not hreeding in northern regions, 70 Bechstein, ' Stubenvogel,' s. 242.

see Latham's ' Hist, of Birds,' vol. viii., T1 Crawfurd's 'Descriptive Diet, of

1823, p. 169. the Indian Islands,' 1656, p. 145.

•7 'Mem. par divers Savans, Acad.

198 STERILITY FROM Chap. XVIII.

via, but subsequently became quite fertile ; and the English Game
fowl, lately introduced, bad not as yet arrived at its full fertility, for
to raise two or three chickens from a nest of eggs was thought for-
tunate. In Europe close confinement has a marked effect on the
fertility of the fowl : it has been found in France that with fowls
allowed considerable freedom only twenty per cent, of the eggs
failed ; when allowed less freedom forty per cent, failed ; and in
. close confinement sixty out of the hundred were not hatched.72 So
we see that unnatural and changed conditions of life produce some
effect on tbe fertility of our most thoroughly domesticated animals,
in the same manner, though in a far less degree, as with captive
wild animals.

It is by no means rare to find certain males and females which
will not breed together, though both are known to be perfectly fer-
tile with other males and females. We have no reason to suppose
that this is caused by these animals having been subjected to any
change in their habits of life ; therefore such cases are hardly re-
lated to our present subject. The cause apparently lies in an innate
sexual incompatibility of the pair which are matched. Several in-
stances have been communicated to me by Mr. W. C. Spooner (well
known for his essay on Cross-breeding), by Mr. Eyton of Eyton, by
Mr. Wicksted and other breeders, and especially by Mr. Waring of
Chelsneld, in relation to horses, cattle, pigs, foxhounds, other dogs,
and pigeons.73 In these cases, females, which either previously or
subsequently were proved to be fertile, failed to breed with certain
males, with whom it was particularly desired to match them. A
change in the constitution of the female may sometimes have oc-
curred before she was put to the second male ; but in other cases this
explanation is hardly tenable, for a female, known not to be barren,
has been unsuccessfully paired seven or eight times with the same
male likewise known to be perfectly fertile. With cart-mares,
which sometimes will not breed with stallions of pure blood, but
subsequently have bred with cart-stallions, Mr. Spooner is inclined
to attribute the failure to the lesser sexual power of the race-horse.
But I have heard from the greatest breeder of race-horses at the
present day, through Mr. Waring, that " it frequently occurs with
" a mare to be put several times during one or two seasons to a
" particular stallion of acknowledged power, and yet prove barren :
" the mare afterwards breeding at once with some other horse."
These facts are worth recording, as they show, like so many pre-

™ ' Bull, de la Soc. Acclimat.' torn. TS For pigeons, see Dr. Chapuis, ' Le

ix., 1S62, pp. 8S0, 884. Pigeon Voyageur Beige,' 1885, p. 66.

Chap. XVIII. CHANGED CONDITIONS. ISM

vions facts, on what slight constitutional differences the fertility of
an animal often depends.

Sterility of Plants from changed Conditions of Life, and
from other causes.

In the vegetable kingdom cases of sterility frequently
occur, analogous with those previously given in the ani-
mal kingdom. But the subject is obscured by several
circumstances, presently to be discussed, namely, the
contabescence of the anthers, as Gartner has named a
certain affection — monstrosities — doubleness of the flower
— much-enlarged fruit — and long-continued or excessive
propagation by buds.

It is notorious that many plants in our gardens and hot-houses,
though preserved in the most perfect health, rarely or never pro-
duce seed. I do not allude to plants which run to leaves, from
being kept too damp, or too warm, or too much manured ; for these
do not produce the reproductive individual or flower, and the case
may be wholly different. Nor do I allude to fruit not ripening
from want of heat, or rotting from too much moisture. But many
exotic plants, with their ovules and pollen appearing perfectly
sound, will not set any seed. The sterility in many cases, as I
know from my own observation, is simply due to the absence of
the proper insects for carrying the pollen to the stigma. But after
excluding the several cases just specified, there are many plants in
which the reproductive system has been seriously affected by the
altered conditions of life to which they have been subjected.

It would be tedious to enter on many details. Linnaeus long ago
observed74 that Alpine plants, although naturally loaded with seed,
produce either few or none when cultivated in gardens. But ex-
ceptions often occur : the Draba syhestris, one of our most thorough-
ly Alpine plants, multiplies itself by seed in Mr. H. C. Watson's
garden, near London ; and Kerner, who has particularly attended
to the cultivation of Alpine plauts, found that various kinds, when
cultivated, spontaneously sowed themselves.7* Many plants which

74 'Swedish Acts,1 vol. i., 1739, p. 3. 'Cybele Britannica,' vol. i. p. 131 ; Mr.

Pallas makes the same remark in his D. Cameron, also, has written on the

Travels (Eng. translat.), vol. i. p. 292. culture of Alpine plants in ' Card.

76 A. Kerner, ' Die Cultur der Al- Chronicle,' 1843, pp. 253, 268, and men-

penpflanzen,' 18G1, s. 139 ; Watson's tions a few which seed.

200 STERILITY FROM Chap. XVIIL

naturally grow in peat-earth are entirely sterile in our gardens. I
have noticed the same fact with several liliaceous plants, which
nevertheless grew vigorously.

Too much manure renders some kinds utterly sterile, as I Lave
myself observed. The tendency to sterility from this cause runs
in families; thus, according to Gartner,76 it 'is hardly possible to
give too much manure to most Gramineae, Cruciferae, and Legumi-
nosa?, whilst succulent and bulbous-rooted plants are easily affected.
Extreme poverty of soil is less apt to induce sterility ; but dwarfed
plants of Trifolium minus and repens, growing on a lawn often
mown and never manured, did not produce any seed. The tem-
perature of the soil, and the season at which plants are watered,
often have a marked effect on their fertility, as was observed by
Kolreuter in the case of Mirabilis." Mr. Scott in the Botanic Gar-
dens of Edinburgh observed that Oncidium divarication would not
set seed -when grown in a basket in. which it throve, but was capa-
ble of fertilisation in a pot where it was a little damper. Pelargo-
nium fidgidum, for many years after its introduction, seeded freely ;
it then became sterile; now it is fertile78 if kept in a dry stove
during the winter. Other varieties of pelargonium are sterile and
otbers fertile without our being able to assign any cause. Very
slight changes in the position of a plant, whether planted on a
bank or at its base, sometimes make all the difference in its pro-
ducing seed. Temperature apparently has a much more powerful
influence on the fertility of plants than on that of animals. Never-
theless, it is wonderful what changes some few plants will with-
stand with undiminished fertility ; thus the Zephyr anthes Candida,
a native of the moderately warm banks of the Plata, sows itself
in the hot dry country near Lima, and in Yorkshire resists the
severest frosts, and I have seen seeds gathered from pods which
had been covered with snow during three weeks.79 Beroeris Wal-
licltii, from the hot Khasia range in India, is uninjured by our
sharpest frosts, and ripens its fruit under our cool summers. Nev-
ertheless I presume we must attribute to change of climate the
6terility of many foreign plants ; thus the Persian and Chinese
lilacs (Syringa Persica and Chinensis), though perfectly hardy,
never here produce a seed; the common lilac (S. vulgaris) seeds
with us moderately well, but in parts of Germany the capsules
never contain seed.*0

'« 'Beitrage zur Kenntniss der Be- ™ Dr. Herbert, ' Amaryllidaceae,' p.

frucbtung,' 1S44, s. 333. 176.

" ' Nova Acta Petrop.,' 1793, p. 391. 80 Gartner, ' Beitrage zur Kenntniss,'

« ' Cottage Gardener,' 1856, pp. 44, Ac, s. 560, 564.
109.

Chap. XVIII. CHANGED CONDITIONS. 201

Some of the cases, given in the last chapter, of self-impotent
plants, which are fertile both on the male and female side when
united with distinct individuals or species, might have been here
introduced ; for as this peculiar form of sterility generally occurs
with exotic plants orwwith endemic plants cultivated in pots, and
as it disappeared in the Passiflora alata when grafted, we may con-
clude that in these cases it is the result of the treatment to which
the plants or their parents have been exposed.

The liability of plants to be affected in their fertility by slightly
changed conditions is the more remarkable, as the pollen when
once in process of formation is not easily injured ; a plant may be
transplanted, or a branch with flower-buds be cut off and placed in
water, and the pollen will be matured. Pollen, also, when once
mature, may be kept for weeks or even months.81 The female
organs are more sensitive, for Gartner "2 found that dicotyledonous
plants, when carefully removed so that they did not in the least
flag, could seldom be fertilised ; this occurred even with potted
plants if the roots had grown out of the hole at the bottom. In
some few cases, however, as with Digitalis, transplantation did not
prevent fertilization ; and according to the testimony of Mawz,
Brassica rapa, when pulled up by its roots and placed in water,
ripened its seed. Flower-stems of several monocotyledonous plants
when cut off and placed in water likewise produce seed. But in
these cases I presume that the flowers had been already fertilised,
for Herbert " found with the Crocus that the plants might be
removed or mutilated after the act of fertilisation, and would still
perfect their seeds ; but that, if transplanted before being fertilised,
the application of pollen was powerless.

Plants which have been long cultivated can generally endure
with undiminished fertility various and great changes; but not in
most cases so great a change of climate as domesticated animals.
It is remarkable that many plants under these circumstances are so
much affected that the proportions and the nature of their chemical
ingredients are modified, yet their fertility is unimpaired. Thus, as
Dr. Falconer informs me, there is a great difference in the character
of the fibre in hemp, in the quantity of oil in the seed of the Li-
num, in the proportion of narcotin to morphine in the poppy, in
gluten to starch in wheat, when these plants are cultivated on the
plains and on the mountains of India ; nevertheless, they all remain
fully fertile.

81 ' Gardener's Chronicle,' 1S44, p. 252, 833.
215; 1S50, p. 470. 8S ' Journal of Ilort. Soc,.' VOL ii.

" ' Beitrage zur Kenntniss,' 4c, s. 1S47, p. S3.

202 CONTABESCENCE. Chap. XVIIL

Contabescence. — Giirtner has designated by this term a peculiar
condition of the anthers in certain plants, in which they are shriv-
elled, or become brown and tough, and contain no good pollen.
When in this state they exactly resemble the anthers of the most
sterile hybrids. Gartner,84 in his discussion on this subject, has
shown that plants of many orders are occasionally thus affected ; but
the Caryophyllaceae and Liliaceae suffer most, and to these orders, I
think, the Ericaceae may be added. Contabescence varies in de-
gree, but on the same plant all the flowers are generally affected
to nearly the same extent. The anthers are affected at a very early
period in the flower-bud, and remain in the same state (w-ith one
recorded exception) during the life of the plant. The affection
cannot be cured by any change of treatment, and is propagated
by layers, cuttings, &c., and perhaps even by seed. In contabe-
scent plants the female organs are seldom affected, or merely be-
come precocious in their development. The cause of this affection
is doubtful, and is different in different cases. Until I read Gart-
ner's discussion I attributed it, as apparently did Herbert, to the un-
natural treatment of the plants ; but its permanence under changed
conditions, and the female organs not being affected, seem incompa-
tible with this view. The fact of several endemic plants becoming
contabescent in our gardens seems, at first sight, equally incompati-
ble with this view ; but Kolreuter believes that this is the result of
their transplantation. The contabescent plants of Dianthus and Ver-
bascum, found wild by Wiegmann, grew on a dry and sterile bank.
The fact that exotic plants are eminently liable to this affection also
seems to show that it is in some manner caused by their unnatural
treatment. In some instances, as with Silene, Gartner's view seems
the most probable, namely, that it is caused by an inherent tenden-
cy in the species to become dioecious. I can add another cause,
namely, the illegitimate unions of reciprocally dimorphic or tri-
morphic plants, for I have observed seedlings of three species of
Primula and of Ly thrum salicaria, which had been raised from
plants illegitimately fertilised by their own-form pollen, with some
or all their anthers in a contabescent state. There is perhaps an ad-
ditional cause, namely, self-fertilisation ; for many plants of Dianthus
and Lobelia, which had been raised from self-fertilised seeds, had their
anthers in this state ; but these instances are not conclusive, as both
genera are liable from other causes to this affection.

Cases of an opposite nature likewise occur, namely, plants with

e« ' Beitrage zur Kenntniss,' 4c., s. 117 Herbert, ' AmarJ•llidacea;,, p. 855. Wieg-
xt seq.; Kolreuter, ' Zweite Fortsetzung,' mant), ' Ueber die Bastarderzeugung,'
s. 10, 121 ; ' Dritte Fortsetzung,' s. 57. 8. 27.

Chap. XVIII. STERILITY. 203

the female organs struck -with sterility, whilst the male organs
remain perfect. Dianthus Japonicus, a Passiflora, and Nicotiana,
have heen described by Gartner65 as being in this unusual condi-
tion.

Monstrosities as a cause of Sterility. — Great deviations of struc-
ture, even when the reproductive organs themselves are not seri-
ously affected, sometimes cause plants to become sterile. But in
other cases plants may become monstrous to an extreme degree
and yet retain their full fertility. Gallesio, who certainly had
great experience/6 often attributes sterility to this cause ; but it
may be suspected that in some of his cases sterility was the
cause, and not the result, of the monstrous growths. The curi-
ous St. Valery apple, although it bears fruit, rarely produces seed.
The wonderfully anomalous flowers of Begonia frigida, formerly
described, though they appear fit for fructification, are sterile.87
Species of Primula?, in which the calyx is brightly coloured, are
said M to be often sterile, though I have known them to be fertile.
On the other hand, Verlot gives several cases of proliferous flowers
which can be propagated by seed. This was the case with a poppy,
which had become monopetalous by the union of its petals.89 An-
other extraordinary poppy, with the stamens replaced by numerous
small supplementary capsules, likewise reproduces itself by seed.
This has also occurred with a plant of Saxifra geum, in which a
series of adventitious carpels, bearing ovules on their margins,
had been developed between the stamens and the normal car-
pels.90 Lastly, with respect to peloric flowers, which depart won-
derfully from the natural structure, — those of Linaria vulgaris
seem generally to be more or less sterile, whilst those before de-
scribed of Antirrhinum majus, when artificially fertilised with their
own pollen, are perfectly fertile, though sterile when left to them-
selves, for bees are unable to crawl into the narrow tubular flower.
The peloric flowers of Corydalis solida, according to Godron,91 are
barren ; whilst those of Gloxinia are well known to yield plenty of
seed. In our greenhouse Pelargoniums, the central flower of the
truss is often peloric, and Mr. Masters informs me that he tried in

85 ' Bastarderzeugung,' s. 35'5. Harvey, on the authority of Mr. An-

84 ' Teoria della Riproduzione,' 1S1C, drew?, who discovered the plant, in-

p. 84; ' Traite du Citrus,' 1811, p. 6T. formed, me that this monstrosity could

87 Mr. C. W. Crocker, in ' Gard. Chron- be propagated by seed. With respect
icle,' 1S61, p. 1092. to the poppy, eee Prof. Goeppert, as

88 Verlot, ' Des Varietes,' 1S65, p". 80. quoted in ' Journal of Horticulture,'
*■» Verlot, idem, p. 88. July 1st, 1S63, p. 171.

50 Prof. Allman, Brit. Assoc, quoted 91 ' Comptes Rendus,' Dec. 19th, 1S64,

In the ' Phytologist,' vol ii. p. 483. Prof. p. 1039.

204 DOUBLE FLO WEES. Chap- XVIII.

vain during several years to get seed from these flowers. I like-
wise made many vain attempts, but sometimes succeeded in ferti-
lising them with pollen from a normal flower of another variety ;
and conversely I several times fertilised ordinary flowers with pe-
loric pollen. Only once I succeeded in raising a plant from a pelo-
ric flower fertilised by pollen from a peloric flower borne by another
variety ; but the plant, it may be added, presented nothing particu-
lar in its structure. Hence we may conclude that no general rule
can be laid down ; but any great deviation from the normal struc-
ture, even when the reproductive organs themselves are not seri-
ously affected, certainly often leads to sexual impotence.

Double Floicers. — When the stamens are converted into petals,
the plant becomes on the male side sterile ; when both stamens and
pistils are thus changed, the plant becomes completely barren.
Symmetrical flowers having numerous stamens and petals are the
most liable to become double, as perhaps follows from all multiple
organs being the most subject to variability. But flowers furnished
with only a few stamens, and others which are asymmetrical in
structure, sometimes become double, as we see with the double
gorse or Ulex, Petunia, and Antirrhinum. The Composite bear
what are called double flowers by the abnormal development of the
corolla of their central florets. Doubleness is sometimes connected
with prolification,92 or the continued growth of the axis of the
flower. Doubleness is strongly inherited. No one has produced, as
Lindley remarks,"3 double flowers by promoting the perfect health
of the plant. On the contrary, unnatural conditions of life favour
their production. There is some reason to believe that seeds kept
during many years, and seeds believed to be imperfectly fertilized,
yield double flowers more freely than fresh and perfectly fertilized
seed.04 Long-continued cultivation in rich soil seems to be the
commonest exciting cause. A double narcissus and a double
Anthemis nobilis, transplanted into very poor soil, have been ob-
served to become single ; *5 and I have seen a completely double
white primrose rendered permanently single by being divided and
transplanted whilst in full flower. It has been observed by Profes-
sor Morren that doubleness of the flowers and variegation of the
leaves are antagonistic states ; but so many exceptions to the rule

92 ' Gardener's Chronicle,' 1866, p. 6S1. of the anthers, see Mr. Leitner, in Silli-

83 ' Theory of Horticulture,' p. 333. man's ' North American Journ. of Sci-

94 Mr. Fairweather, in 'Transact. ence,' vol. xxiii. p. 47; and Verlot, ' Des

Hovt. Soc.,' vol. iii. p. 406 ; Bosse, quoted Varietes,' 1865, p. 84.

byBronn, ' Geschichte der Natur,' B. ii. 96 Lindley's ' Theory of Horticulture,'

s. 77. On the effects of the removal p. 333.

Chap. XVIII. STERILITY. 205

have lately been recorded," that, though general, it cannot be
looked at as invariable. Variegation seems generally to result from
a feeble or atrophied condition of the plant, and a large proportion
of the seedlings raised from parents both of which are variegated
usually perish at an early age ; hence we may perhaps infer that
dmibleness, which is the antagonistic state, commonly arises from
a plethoric condition. On the other hand, extremely poor soil
sometimes, though rarely, appears to cause doubleness : I formerly
described 9' some completely double, bud-like, flowers produced in
large numbers by stunted wild plants of Gentiana amarella grow-
ing on a poor chalky bank. I have also noticed a distinct tendency
to doubleness in the flowers of a Ranunculus, Horse-chesnut, and
Bladder-nut (Ranunculus repens, JEsculus Pavia, and Staphylea),
growing under very unfavourable conditions. Professor Lehman 9a
found several wild plants growing near a hot spring with double
flowers. With respect to the cause of doubleness, which arises, as
we see, under widely different circumstances, I shall presently at-
tempt to show that the most probable view is that unnatural condi-
tions first give a tendency to sterility, and that then, on the principle
of compensation, as the reproductive organs do not perform their
proper functions, they either become developed into petals, or addi-
tional petals are formed. This view has lately been supported by
Mr. Laxton," who advances the case of some common peas, which,
after long-continued heavy rain, flowered a second time, and pro-
duced double flowers.

Seedless Fruit. — Many of our most valuable fruits, although con-
sisting in a homological sense of widely different organs, are either
quite sterile, or produce extremely few seeds. This is notoriously
the case with our best pears, grapes, and figs, with the pine-apple,
banana, bread-fruit, pomegranate, azarole, date-palms, and some
members of the orange-tribe. Poorer varieties of these same fruits
either habitually or occasionally yield seed.100 Most horticulturists

98 'Gardener's Chronicle,' 1SC5, p. ii. p. 106; Pickering, ' Races of Man;'

62G; 1S66, pp. 290, 730; and Verlot, Gallesio, 'Teoria della Riproduzione,'

' Des Varietes,' p. 75. 1S16, p. 101-110. Meyen (' Reise ura

"'Gardener's Chronicle,' 1S43, p. Erde,' Th. ii. s. 214) states that at Manil-

628. In this article I suggested the fol- la one variety of the banana is full of

lowing theory on the doubleness of seeds; and Chamisso (Hooker's ' Bot.

flowers. Misc.,' vol. i. p. 310) describes a variety

98 Quoted by Gartner, ' Bastarderzeu- of the bread-fruit in the Mariana Islands

gung,' s. 567. with small fruit, containing seeds which

•• ' Gardener's Chronicle,' 1866, p. are frequently perfect. Burnes, in his

901. ' Travels in Bokhara,' remarks on the

100 Lindley, 'Theory of Horticulture,' pomegranate seeding in Mazenderan, as

p. 175-179 ; Godron, ' De I'Especc, toui. a remarkable peculiarity.

206 STERILITY. Chap. XVIII.

look at the great size and anomalous development of the fruit as
the cause, and sterility as the result ; hut the opposite view, as we
shall presently see, is more probable.

Sterility from the excessive development of the Organs of Growth
or Vegetation. — Plants which from any cause grow too luxuriantly,
and produce leaves, stems, runners, suckers, tubers, bulbs, &c, in
excess, sometimes do not flower, or if they flower do not yield seed.
To make European vegetables under the hot climate of India yield
seed, it is necessary to check their growth ; and, when one-third
grown, they are taken up, and their stems and tap-roots are cut or
mutilated.101 So it is with hybrids; for instance, Prof. Lecoq 10*
had three plants of Mirabilis, which, though they grew luxuriantly
and flowered, were quite sterile ; but after beating one with a stick
until a few branches alone were left, these at once yielded good seed.
The sugar-cane, which grows vigorously and produces a large sup-
ply of succulent stems, never, according to various observers, bears
seed in the West Indies, Malaga, India, Cochin China, or the Malay
Archipelago.103 Plants which produce a large number of tubers
are apt to be sterile, as occurs, to a certain extent, with the common
potato ; and Mr. Fortune informs me that the sweet potato (Convol-
vulus batatas) in China never, as far as he has seen, yields seed. Dr.
Royle remarks 104 that in India the Agave vivipara, when grown in
rich soil, invariably produces bvdbs, but no seeds ; whilst a poor
soil and dry climate leads to an opposite result. In China, accord-
ing to Mr. Fortune, an extraordinary number of little bulbs are de-
veloped in the axils of the leaves of the yam, and this plant does
not bear seed. Whether in these cases, as in those of double flowers
and seedless fruit, sexual sterility from changed conditions of life is
the primary cause which leads to the excessive development of the
organs of vegetation, is doubtful ; though some evidence might be
advanced in favour of this view. It is perhaps a more probable
view that plants which propagate themselves largely by one method,
namely by buds, have not sufficient vital power or organized matter
for the other method of sexual generation.

Several distinguished botanists and good practical judges believe
that long-continued propagation by cuttings, runners, tubers, bulbs,
&c, independently of any excessive development of these parts, is
the cause of many plants failing to produce flowers and of others
failing to produce fertile flowers, — it is as if they had lost the habit

101 Ingledew, in ' Transact, of Agricult. Gallesio, ' Teoria della Riproduzione,' p.

and Hort. Soc. of India,' vol. ii. 110.

im 'De la Fecondation,' 1862, p. 308. »°* 'Transact. Linn. Soc.,' vol. xvii. p.

10S Hooker's ' Bot. Misc.,' vol. i. p. 99 ; 563.

Chap. XVIII. STERILITY. 207

of sexual generation.105 That many plants -when thus propagated
are sterile there can be no doubt ; but whether the long continuance
of this form of propagation is the actual cause of their sterility, I
will not venture, from the want of sufficient evidence, to express an
opinion.

That plants may be propagated for long periods by buds, without
the aid of sexual generation, we may safely infer from this being
the case with many plants which must have long survived in a
state of nature. As I have had occasion before to allude to this sub-
ject, I will here give such cases as I have collected. Many alpine
plants ascend mountains beyond the height at which they can
produce seed.108 Certain species of Poa and Festuca, when growing
on mountain-pastures, propagate themselves, as I hear from Mr.
Bentham, almost exclusively by bulblets. Kalm gives a more curi-
ous instance 107 of several American trees, which grow so plentifully
in marshes or in thick woods, that they are certainly well adapted
for these stations, yet scarcely ever produce seeds ; but when acci-
dentally growing on the outside of the marsh or wood, are loaded
with seed. The common ivy is found in Northern Sweden and
Russia, but flowers and fruits only in the southern provinces. The
Acorus calamus extends over a large portion of the globe, but so
rarely perfects its fruit that this has been seen but by few botan-
ists.10" The Hypericum calycinum, which propagates itself so freely
in our shrubberies by rhizomas, and is naturalised in Ireland, blossoms
profusely, but sets no seed ; nor did it set any when fertilised in my
garden by pollen from plants growing at a distance. The Lysima-
chiii nummularia, which is furnished with long runners, so seldom
produces seed-capsules, that Prof. Decaisne,109 who has especially
attended to this plant, has never seen it in fruit. The Carex rigida
often fails to perfect its seed in Scotland, Lapland, Greenland, Ger-
many, and New Hampshire in the United States.110 The periwinkle
( Vinca minor), which spreads largely by runners, is said scarcely

105 Godron, 'De l'Espece,' torn. ii. p. translat., vol. iii. p. 175.

106; Herbert on Crocus, in 'Journal 108 With respect to the ivy and Acorus,

of Hort. Soc.,' vol. i., 1S46, p. 254 — Dr. see Dr. Bromfield in the ' Phytologist,"

Wight, from what he has seen in India, vol. iii. p. 3T6. See also Lindley and

believea in this view ; ' Madras Journal Vaucher on the Acorus.

of Lit. and Science,' vol. iv., 1S36, p. 61. 109 'Annal. des Sc. Nat.,' 3rd series,

109 Wahlenberg specifies eight species Zool., torn. iv. p. 280. Prof. Decaisne

in this state on the Lapland Alps : see refers also to analogous cases with

Appendix to Linrueus' ' Tour in Lap- mosses and lichens near Paris,

land,' translated by Sir J. E. Smith, vol. 110 Mr. Tuckerman, in Silliman's

ii. pp. 274-2S!>. 'American Journal of Science,' vol. xlv.

107 'Travels in North America,' Eng. p. 41.

208 STEEILITY. Chap. XVin.

ever to produce fruit in England ; m but this plant requires insect-
aid for its fertilisation, and the proper insects may be absent or rare.
The Jussicea grandiflora has become naturalised in Southern France,
and has spread by its rhizomas so extensively as to impede the navi-
gation of the waters, but never produces fertile seed.112 The horse-
radish (Cochlearia armoracia), spreads pertinaciously and is natural-
ised in various parts of Europe ; though it bears flowers, these
rarely produce capsules : Professor Caspary also informs me that he
has watched this plant since 1851, but has never seen its fruit ; nor
is this surprising, as he finds scarcely a grain of good pollen. The
common little Ranunculus ficaria rarely, and some say never, bears
Beed in England, France, or Switzerland ; but in 1863 I observed
seeds on several plants growing near my house. According to M.
Chatin, there are two forms of this Ranunculus ; and it is the bulbi-
ferous form which does not yield seed from producing no pollen. ns
Other cases analogous with the foregoing could be given ; for
instance, sdme kinds of mosses and lichens have never been seen to
fructify in France.

Some of these endemic and naturalised plants are probably ren-
dered sterile from excessive multiplication by buds, and their conse-
quent incapacity to produce and nourish seed. But the sterility of
others more probably depends on the peculiar conditions under
which they live, as in the case of the ivy in the northern parts of
Europe, and of the trees in the swamps of the United States ; yet
these plants must be in some respects eminently well adapted for
the stations which they occupy, for they hold their places against a
host of competitors.

Finally, when we reflect on the sterility which accom-
panies the doubling of flowers, — the excessive develop-
ment of fruit, — and a great increase in the organs of vege-
tation, we must bear in mind that the whole effect has
seldom been caused at once. An incipient tendency is
observed, and continued selection completes the work, as

:l1 Sir J. E. Smith, 'English Flora,' p. 33 ; Lecoq, ' Geograph. Bot. de l'Eu-

vol. i. p. 339. rope,' torn. iv. p. 466 ; Dr. D. Clos, in

113 G. Planchon, 'Flora de Montpel- ' Annal. des Sc. Nat.,' 3rd series, Bot.,

Her,' 1SG4, p. 20. torn, xvii., 1852. p. 129 : this latter author

'13 On the non-production of seeds in refers to other analogous cases. On the

England nee Mr. Crocker, in ' Gardener's non-production of pollen by this Uanun-

Weekly Magazine,' 1S52, p. 70 ; Vaucher, cuius see Chatin, in ' Comptes Rendus,'

'Hist. Phys. Plantes d'Europe,' torn. i. June 11th, 1866.

Chap. XVIIL

STERILITY. 209

is known to be the case with our double flowers and best
fruits. The view which seems the most probable, and
which connects together all the foregoing facts and brings
them within our present subject, is, that changed and un-
natural conditions of life first give a tendency to sterility ;
and in consequence of this, the organs of reproduction
being no longer able fully to perform their proper func-
tions, a supply of organised matter, not required for
the development of the seed, flows either into these same
organs and renders them foliaceous, or into the fruit,
stems, tubers, &c:, increasing their size and succulency.
But I am fir from wishing to deny that there exists, in-
dependently of any incipient sterility, an antagonism be-
tween the two forms of reproduction, namely, by seed
and by buds, when either is carried to an extreme degree.
That incipient sterility plays an important part in the
doubling of flowers, and in the other cases just specified,
I infer chiefly from the following facts. When fertility
is lost from a wholly different cause, namely, from hy-
bridism, there is a strong tendency, as Gartner114 affirms,
for flowers to become double, and this tendency is inher-
ited. Moreover it is notorious that with hybrids the
male organs become sterile before the female organs, and
with double flowers the stamens first become foliaceous.
This latter fact is well shown by the male flowers of
dioecious plants, which, according to Gallesio,115 first be-
came double. Again, Gartner 116 often insists that the
flowers of even utterly sterile hybrids, which do not pro-
duce any seed, generally yield perfect capsules or fruit, —
a fact which has likewise been repeatedly observed by
Naudin with the Cucurbitacea? ; so that the production
of fruit by plants rendered sterile through any other and

114 ' Bastarderzeugung,' s. 565. K61- tremely double,

reuter (' Dritte Fortsetzung,' s. 73, 87, 115 ' Teoria della Riproduzione Veg

118) Blso shows that when two species, 1S16, p. 73.

one single and the other double, are 116 ' Bastarderzeugung,' s. 578.
crossed, the hybrids are apt to be ex-

210 STERILITY. Chap. XVIIL

distinct cause is intelligible. Kolreuter has also express-
ed his unbounded astonishment at the size and develop-
ment of the tubers in certain hybrids ; and all experimen-
talists U7 have remarked on the strong tendency in hybrids
to increase by roots, runners, and suckers. Seeing that
hybrid plants, which from their nature are more or less
sterile, thus tend to produce double flowers ; that they
have the parts including the seed, that is the fruit, per-
fectly developed, even when containing no seed ; that
they sometimes yield gigantic roots ; that they almost
invariably tend to increase largely by suckers and other
such means ; — seeing this, and knowing, from the many
facts given in the earlier parts of this chapter, that al-
most all organic beings when exposed to unnatural con-
ditions tend to become more or less sterile, it seems much
the most probable view that with cultivated plants ste-
rility is the exciting cause, and double flowers, rich seed-
less fruit, and in some cases largely-developed organs of
vegetation, &c, are the indirect results — these results
having been in most cases largely increased through
continued selection by man.

117 ' Bastarderzeugung,' s. 527.

Cmp. xix. 8UMMABY OF FOUR LAST CHAPTERS. 211

CHAPTER XIX.

SUMMARY OF THE FOUR LAST CHAPTERS, WITH RE-
MARKS ON HYBRIDISM.

ON THE EFFECTS OF CROSSING — THE INFLUENCE OF DOMESTICA-
TION ON FERTILITY — CLOSE INTERBREEDING — GOOD AND EVIL
RESULTS FRO;*! CHANGED CONDITIONS OF LIFE — VARIETIES
WHEN CROSSED NOT INVARIABLY FERTILE — ON THE DIFFER-
ENCE IN FERTILITY BETWEEN CROSSED SPECIES AND VARIE-
TIES— 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 REPRO-
DUCTIVE 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.

It was shown in the fifteenth chapter that when indi-
viduals of the same variety, or even of a distinct variety,
are allowed freely to intercross, uniformity of character
is ultimately acquired. Some few characters, however,
are incapable of fusion, but these are unimportant, as
they are almost always of a semi-monstrous nature, and
have suddenly appeared. Hence, to preserve our do-
mesticated breeds true, or to improve them by methodi-
cal selection, it is obviously necessary that they should
be kept separate. Nevertheless, through unconscious
selection, a whole body of individuals may be slowly
modified, as we shall see in a future chapter, without
separating them into distinct lots. Domestic races have
often been intentionally modified by one or two crosses,

212 SUMMARY OF THE Chap. XIX.

made with some allied race, and occasionally even by re-
peated crosses with very distinct races ; but in almost all
such cases, long-continued and careful selection has been
absolutely necessary, owing to the excessive variability
of the crossed offspring, due to the principle of reversion.
In a few instances, however, mongrels have retained a
uniform character from their first production.

When two varieties are alloAved to cross freely, and
one is much more numerous than the other, the former
will ultimately absorb the latter. Should both varieties
exist in nearly equal numbers, it-is probable that a con-
siderable period would elapse before the acquirement
of a uniform character ; and the character ultimately ac-
quired would largely depend on prepotency of transmis-
sion, and on the conditions of life ; for the nature of these
conditions would generally favour one variety more than
another, so that a kind of natural selection would come
into play. Unless the crossed offspring were slaughter-
ed by man without the least discrimination, some degree
of unmethodical selection would likewise come into ac-
tion. Fi-orn these several considerations we may infer,
that when two or more closely allied species first came
into the possession of the same tribe, their crossing will
not have influenced, in so great, a degree as has often
been supposed, the character of the offspring in future
times ; although in some cases it probably has had a con-
siderable effect.

Domestication, as a general rule, increases the proli-
ficness of animals and plants. It eliminates the tendency
to sterility which is common to species when first taken
from a state of nature and crossed. On this latter head
we have no direct evidence ; but as our races of dogs,
cattle, pigs, &c, are almost certainly descended from
aboriginally distinct stocks, and as these races are now
fully fertile together, or at least incomparably more fer-
tile than most species when crossed, we may with much
confidence accept this conclusion. '

Chap. XIX. FOUR LAST CHAPTERS. 213

Abundant evidence has been given that crossing adds
to the size, vigour, and .fertility of the offspring. This
holds good when there has been no previous close inter-
breeding. It applies to the individuals of the same va-
riety but belonging to different families, to distinct va-
rieties, sub-species, and partially even to species. In the
latter case, though size is often gained, fertility is lost ;
but the increased size, vigour, and hardiness of many hy-
brids cannot be accounted for solely on the principle of
compensation from the inaction of the reproductive sys-
tem. Certain plants, both of pure and hybrid origin,
though perfectly healthy, have become self-impotent, ap-
parently from the unnatural conditions to which they
have been exposed ; and such plants, as well as others in
their normal state, can be stimulated to fertility only by
crossing them with other individuals of the same species
or even of a distipct species.

On the other hand, long-continued close interbreeding
between the nearest relations diminishes the constitution-
al vigour, size, and fertility of the offspring ; and occasion-
ally leads to malformations, but not necessarily to general
deterioration ofcform or structure. This failure of fertil-
ity shows that the evil results of interbreeding are inde-
pendent of the augmentation of morbid tendencies com-
mon to both parents, though this augmentation no doubt
is often highly injurious. Our belief that evil follows
from close interbreeding rests to a large extent on the
experience of practical breeders, especially of those who
have reared many animals of the kinds which can be pro-
pagated quickly ; but it likewise rests on several care-
fully recorded experiments. With some animals close
interbreeding may be carried on for a long period with
impunity by the selection of the most vigorous and healthy
individuals; but sooner or later evil follows. The evil,
however, comes on so slowly and gradually that it easily
escapes observation, but can be recognised by the almost
instantaneous manner in which size, constitutional vigour,

214 SUMMARY OF THE Chap. XIX.

and fertility are regained when animals that have long
been interbred are crossed with a distinct family.

These two great classes of facts, namely the good de-
rived from crossing, and the evil from close interbreeding,
with the consideration of the innumerable adaptations
throughout nature for compelling, or favouring, or at least
permitting, the occasional union of distinct individuals,
taken together, lead to the conclusion that it is a law of
nature that organic beings shall not fertilise themselves
for perpetuity. This law was first plainly hinted at in
1799, with respect to plants, by Andrew Knight,1 and,
not long afterwards, that sagacious observer Kolreuter,
after showing how well the Malvaceae are adapted for
crossing, asks, " an id aliquid in recessu habeat, quod hu-
juscemodi fibres nunquam proprio suo pulvere, sed sem-
per eo aliarum sua? speciei impregnentur, merito quseritur ?
Certe natura nil facit frustra." Although we may demur
to Kolreuter's saying that nature does nothing in vain,
seeing how many organic beings retain rudimentary and
useless organs, yet undoubtedly the argument from the
innumerable contrivances, which fixvour the crossing of
distinct individuals of the same species, is of the greatest
weight. The most important result of this law is that
it leads to uniformity of character in the individuals
of the same species. In the case of certain her-
maphrodites, which probably intercross only at long in-
tervals of time, and with unisexual animals inhabit-
ing somewhat separated localities, which can only oc-
casionally come into contact and pair, the greater vigour
and fertility of the crossed offspring will ultimate!)7 pre-
vail in giving uniformity of character to the individuals

1 'Transactions Phil. Soc.,' f799, p. wonderfully acute observer failed to un-

202. For Kolreuter, see 'Mem. de derstand the full meaning of the structure

l'Acad. de St. Petersbourg,' torn. Hi., of the flowers which he has so well de-

1S09, (published 1811), p. 197. In read- scribed, from not always having before

ing C K. Sprengel's remarkable work, his mind the key to the prob'em, namely,

'Das entdeckte Geheimniss,' &c, 1793, the good derived from the crossing of

It is curious to observe how often this distinct individual plants.

Chap. XIX. FOUR LAST CHAPTERS. 215

of the same species. Bat when we go beyond the limits
of the same species, free intercrossing is barred by the
law of sterility.

In searching for facts which might throw light on the
cause of the good effects from crossing, and of the evil
effects from close interbreeding, Ave have seen that, on the
oue hand, it is a widely prevalent and ancient belief that
animals and plants profit from slight changes in their con-
dition of life; and it would appear that the germ, in a
somewhat analogous manner, is more effectually stimulat-
ed by the male element, when taken from a distinct in-
dividual, and therefore slightly modified in nature, than
when taken from a male having the same identical con-
stitution. On the other hand, numerous facts have been
given, showing that when animals are first subjected to
captivity, even in their native land, and although allowed
much liberty, their reproductive functions are often great-
ly impaired or quite annulled. Some groups of animals
are more affected than others, but with apparently capri-
cious exceptions in every group. Some animals never or
rarely couple : some couple freely, but never or rarely
conceive. The secondary male characters, the maternal
functions and instincts, are occasionally affected. With
plants, when first subjected to cultivation, analogous facts
have been observed. We probably owe our double flow-
ers, rich seedless fruits, and in some cases greatly de-
veloped tubers, &c, to incipient sterility of the above
nature combined with a copious supply of nutriment.
Animals which have long been domesticated, and plants
which have long been cultivated, can generally withstand
with unimpaired fertility great changes in their condi-
tions of life ; though both are sometimes slightly affected.
With animals the somewhat rare capacity of breeding
freely under confinement has mainly determined, together
with their utility, the kinds which have been domes-
ticated.

We can in no case precisely say what is the cause of

216 SUMMARY OF FOUR LAST CHAPTERS. Chap. XIX

the diminished fertility of an animal when first captured,
or of a plant when first cultivated ; we can only infer
that it is caused by a change of some kind in the natural
conditions of life. The remarkable susceptibility of the
reproductive system to such changes, — a susceptibility
not common to any other organ, — apparently has an im-
portant bearing on Variability, as we shall see in a fu-
ture chapter.

It is impossible not to be struck with the double paral-
lelism between the two classes of facts just alluded to.
On the one hand, slight changes in the conditions of life,
and crosses between slightly modified forms or varieties,
are beneficial as far as prolificness and constitutional
vigour are concerned. On the other hand, changes in the
conditions greater in degree, or of a different nature, and
crosses between forms which have been slowly and
greatly modified by natural means, — in other words, be-
tAveen species, — are highly injurious, as far as the repro-
ductive system is concerned, and in some few instances
as far as constitutional vigour is concerned. Can this
parallelism be accidental ? Does it not rather indicate
some real bond of connection ? As a fire goes out unless
it be stirred up, so the vital forces are always tending,
according to Mr. Herbert Spencer, to a state of equili-
brium, unless disturbed and renovated through the action
of other forces.

In some few cases varieties tend to keep distinct, by
breeding at different periods, by great differences in size,
or by sexual preference, — in this latter respect more
especially resembling species in a state of nature. But
the actual ci'ossing of varieties, far from diminishing, gen-
erally adds to the fertility of both the first union and
the mongrel offspring. Whether all the most widely
distinct domestic varieties are invariably quite fertile
when crossed, we do not positively know; much time
and trouble would be requisite for the necessary experi-
ments, and many difficulties occur, such as the descent of

Chap. XIX. HYBRIDISM. 21 7

the various races from aboriginally distinct species, and
the doubts whether certain forms ought to be ranked as
species or varieties. Nevertheless, the wide experience
of practical breeders proves that the great majority of
varieties, even if some should hereafter prove not to be
indefinitely fertile inter se, are far more fertile when
crossed, than the vast majority of closely allied natural
species. A few remarkable cases have, however, been
given on the authority of excellent observers, showing
that with plants certain forms, which undoubtedly must
be ranked as varieties, yield fewer seeds when crossed
than is natural to the pai'ent-species. Other varieties
have had their reproductive powers so far modified that
they are either more or less fertile than are their parents,
when crossed with a distinct species.

Nevertheless, the fact remains indisputable that domes-
ticated varieties of animals and of plants, which differ
greatly from each other in structure, but which are cer-
tainly descended from the same aboi-iginal species, such
as the races of the fowl, pigeon, many vegetables, and a
host of other productions, are extremely fertile when
crossed ; and this seems to make a broad and impassable
barrier between domestic varieties and natural species.
But, as I will now attempt to show, the distinction is
not so great and overwhelmingly important as it at first
appears.

On the Difference in Fertility beticeen Varieties and
Species when crossed.

This work is not the proper place for fully treating the
subject of hybridism, and I have already given in my
' Origin of Species ' a moderately full abstract. I will
here merely enumerate the general conclusions which
may be relied on, and which bear on our present point.

Firstly, the laws governing the production of hybrids
are identical, or nearly identical, in the animal and vege-
table kingdoms.

218 HTBEIDISM. Chap. XIX.

Secondly, the sterility of distinct species when first
united, mid that of their hybrid offspring, graduates, by
an almost infinite number of steps, from zero, when the
ovule is never impregnated and a seed-capsule is never
formed, up to complete fertility. We can only escape
the conclusion that some species are fully fertile when
crossed, by detennining to designate as varieties all the
forms which are quite fertile. This high degree of fer-
tility is, however, rare. Nevertheless plants, which have
been exposed to unnatural conditions, sometimes become
modified in so peculiar a manner, that they are much
more fertile when crossed by a distinct species than when
fertilised by their own pollen. Success in effecting a first
union between two species, and the fertility of their hy-
brids, depends in an eminent degree on the conditions of
life being favourable. The innate sterility of hybrids of
the same parentage and raised from the same seed-cap-
sule often differs much in degree.

Th irdly, the degree of sterility of a first cross between
two species does not always run strictly parallel with that
of their hybrid offspring. Many cases are known of spe-
cies which can be crossed with ease, but yield hybrids ex-
cessively sterile ; and conversely some which can be crossed
with great difficulty, but produce fairly fertile hybrids.
This is an inexplicable fact, on the view that species have
been specially endowed with mutual sterility in order to
keep them distinct.

Fourthly, the degree of sterility often differs greatly in
two species when reciprocally crossed; for the first will
readily fertilise the second; but the latter is incapable,
after hundreds of trials, of fertilising the former. Hy-
brids produced from reciprocal crosses between the same
two species, likewise sometimes differ in their degree of
sterility. These cases also are utterly inexjdicable on
the view of sterility being a special endowment.

Fifthly, the degree of sterility of first crosses and of
hybrids runs, to a certain extent, parallel with the gene-

Chap. XIX. IIYBTUDISM. 219

fal or systematic affinity of the forms which are united.
For species belonging to distinct genera can rarely, and
those belonging to distinct families can never, be crossed.
The parallelism, however, is far from complete ; for a
multitude of closely allied species will not unite, or unite
with extreme difficulty, whilst other species, widely dif-
ferent from each other, can be crossed with perfect faci-
lity. Nor does the difficulty "depend on ordinary consti-
tutional differences, for annual and perennial plants, de-
ciduous and evergreen trees, plants flowering at different
seasons, inhabiting different stations, and naturally living
under the most opposite climates, can often be crossed with
ease. The difficulty or facility apparently depends exclu-
sively on the sexual constitution of the species which are
crossed ; or on their sexual elective affinity, i. e., Wahlver-
icandtseliaft of Gartner. As species rarely or never be-
come modified in one character, without being at the
same time modified in many, and as systematic affinity
includes all visible resemblances and dissimilarities, any
difference in sexual constitution between two species
would naturally stand in more or less close relation with
their systematic position.

Sixthly, the sterility of species when first crossed, and
that of hybrids, may possibly depend to a certain extent
on distinct causes. With pure species the reproductive
organs are in a perfect condition, whilst with hybrids
they are often plainly deteriorated. A hybrid embryo
which partakes of the constitution of its father and
mother is exposed to unnatural conditions, as long as it
is -nourished within the womb, or egg, or seed of the
mother-form ; and as we know that unnatural conditions
often induce sterility, the reproductive organs of the hy-
brid might at this early age be permanently affected.
But this cause has no bearing on the infertility of first
unions. The diminished number of the offspring from
first unions may often result, as is certainly sometimes
the case, from the premature death of most of the hybrid

220 HYBRIDISM. Chap. XTX.

embryos. But we shall immediately see that a law of
an unknown nature apparently exists, which causes the
offspring from unions, which are infertile, to be them-
selves more or less infertile; and this at present is all
that can be said.

Seventhly, hybrids and mongrels present, with the one
great exception of fertility, the most striking accordance
in all other respects ; namely, in the laws of their resem-
blance to their two parents, in their*tendency to rever-
sion, in their variability, and in being absorbed through
repeated crosses by either parent-form.

Since arriving at the foregoing conclusions, condensed
from my former work, I have been led to investigate a
subject which throws considerable light on hybridism,
namely, the fertility of reciprocally dimorphic and tri-
morphic plants, when illegitimately united. I have had
occasion several times to allude to these plants, and I
may here give a brief abstract5 of my observations.
Several plants belonging to distinct orders present two
forms, which exist in about equal numbers, and which
differ in no respect except in their reproductive organs ;
one form having a long pistil with short stamens, the
other a short pistil with long stamens; both with dif-
ferently sized pollen-grains. With trimorphic plants
there are three forms likewise differing in the lengths
of their pistils and stamens, in the size and colour of the
pollen-grains, and in some other respects ; and as in each
of the three forms there are two sets of stamens, there
are altogether six sets of stamens and three kinds of pistils.
These organs are so proportioned in length to each other
that, in any two of the forms, half the stamens in each
stand on a level with the stigma of the third form.
Now I have shown, and the result has been confirmed

2 This abstract was published in (he my original observations on this point
fourth edition (1866) of my ' Origin of have not as yet been published in de-
Species ; ' but as this edition will be in tail, I have ventured here to reprint the
the hands of but few persons, and as abstract.

Chap. XIX. HYBRIDISM. 221

by other observers, that, in order to obtain full fertility
■with these plants, it is necessary that the stigma of the
one form should be fertilized by pollen taken from the
stamens of corresponding height in the other form. So
that with dimorphic species two unions, which may be
called legitimate, are fully fertile, and two, which may
be called illegitimate, are more or less infertile. With
trimorphic species six unions are legitimate or fully fer-
tile, and twelve a»e illegitimate or more or less infertile.
The infertility which may be observed in various di-
morphic and trimorphic plants when they are illegiti-
mately fertilised, that is, by pollen taken from stamens
not corresponding in height with the pistil, differs much
in degree, up to absolute and utter sterility ; just in the
same manner as occurs in crossing distinct species. As
the degree of sterility in the latter case depends in an
eminent degree on the conditions of life being more or
less favourable, so I have found it with illegitimate
unions. It is well known that if pollen of a distinct spe-
cies .be placed on the stigma of a flower, and its own
.pollen be afterwards, even after a considerable interval
of time, placed on the same stigma, its action is so
strongly prepotent that it generally annihilates the effect
of the foreign pollen ; so it is with the pollen of the sev-
eral forms of the same species, for legitimate pollen is
strongly prepotent over illegitimate pollen, -when both are
placed on the same stigma. I ascertained this by fertil-
ising several flowers, first illegitimately, and twenty-four
hours afterwards legitimately, with pollen taken from a
peculiarly coloured variety, and all the seedlings were
similarly coloured ; this shows that the legitimate pollen,
though applied twenty- four hours subsequently, had
wholly destroyed or prevented the action of the pre-
viously applied illegitimate pollen. Again, as, in making
reciprocal crosses between the same two species, there is
occasionally a great difference in the result, so something
analogous occurs with dimorphic plants ; for a short-

222 HYT3EIDISM. Chap. XIX.

styled cowslip (P. veris) yields more seed when fertilised
by the long-styled form, and less seed when fertilised by
its own form, compared with a long-styled cowslip when
fertilised in the two corresponding methods.

In all these respects the forms of the same undoubted
species, when illegitimately united, behave in exactly the
same manner as do two distinct species when crossed.
This led me carefully to observe during four years many
seedlings, raised from several illegitimate unions. The
chief result is that these illegitimate plants, as they may
be called, are not fully fertile. It is possible to raise
from dimorphic species, both long-styled and short-styled
illegitimate plants, and from trimorphic plants all three
illegitimate forms. These can then be properly united in
a legitimate manner. When this is done, there is no
apparent reason why they should not yield as many
seeds as did their parents when legitimately fertilized.
But such is not the case; they are all infertile, but in
various degrees ; some being so utterly and incurably
sterile that they did not yield during four seasons a sin-
gle seed or even seed-capsule. These illegitimate plants,
which are so sterile, although united with each other
in a legitimate manner, may be strictly compared with
hybrids when crossed inter se, and it is well known how
sterile these latter generally are. When, on the other
hand, a hybrid is crossed with either pure parent-species,
the sterility is usually much lessened : and so it is when
an illegitimate plant is fertilised by a legitimate plant.
In the same manner as the sterility of hybrids does not
always run parallel with the difficulty of making the first
cross between the two parent species, so the sterility of
certain illegitimate plants was xmusually great, whilst
the sterility of the union from which they were derived
was by no means great. With hybrids raised from the
same seed-capsule the degree of sterility is innately va-
riable, so it is in a marked manner with illegitimate plants.
Lastly, many hybrids are profuse and persistent flowerers,

Chap. xix. HYBRIDISM. 223

whilst others and more sterile hybrids produce few flow-
ers, and are weak, miserable dwarfs ; exactly similar
cases occur with the illegitimate offspring of various
dimorphic and trimorphic plants.

Altogether there is the closest identity in character
and behaviour between illegitimate plants and hy-
brids. It is hardly an exaggeration to maintain that the
former are hybrids, but produced within the limits of
the same species by the improper union of certain forms,
whilst ordinary hybrids are produced from an improper
union between so-called distinct species. We have al-
ready seen that there is the closest similarity in all re-
spects between first illegitimate unions, and first crosses
between distinct species. This will perhaps be made
more fully apparent by an illustration : we may suppose
that a botanist found two well-marked varieties (and such
occur) of the long-styled form of the trimorphic XytfArwm
salicaria, and that he determined to try by crossing whe-
ther they were specifically distinct. He would find that
they yielded only about one-fifth of the proper number
of seed, and that they behaved in all the other above-
specified respects as if they had been two distinct species.
But to make the case sure, he would raise plants from
his supposed hybridised seed, and he would find that the
seedlings were miserably dwarfed and utterly sterile, and
that they behaved in all other respects like ordinary
hybrids. He might then maintain that he had actually
proved, in accordance with the common view, that his
two varieties were as good and as distinct species as any
in the world ; but he would be completely mistaken.

The facts now given on dimorphic and trimorphic
plants are important, because they show us, firstly, that
the physiological test of lessened fertility, both in first
crosses and in hybrids, is no safe criterion of specific dis-
tinction; secondly, because we may conclude that there
must be some unknown law or bond connecting the in-
fertility of illegitimate unions with that of their illegiti-

224 HYBRIDISM. Chap. XIX.

mate offspring, and we are thus led to extend this view-
to first crosses and hybrids ; thirdly, because we find,
and this seems to me of especial importance, that with
trimorphic plants three forms of the same species exist,
which when crossed in a particular manner are infertile,
and yet these forms differ in no respect from each other,
except in their reproductive organs, — as in the relative
length of the stamens and pistils, in the size, form, and
colour of the pollen-grains, in the structure of the stigma,
and in the number and size of the seeds. With these
differences and no others, either in organisation or con-
stitution, Ave find that the illegitimate unions and the
illegitimate progeny of these three forms are more or
less sterile, and closely resemble in a whole series of re-
lations the first unions and hybrid offspring of distinct
species. From this we may infer that the sterility of
species when crossed and of their hybrid progeny is like-
wise in all probability exclusively due to differences con-
fined to the reproductive system. We have indeed been
brought to a similar conclusion by observing that the
sterility of crossed species does not strictly coincide with
their systematic affinity, that is, with the sum of their
external resemblances ; nor does it coincide with their
similarity in general constitution. But we are more es-
pecially led to this same conclusion by considering reci-
procal crosses, in which the male of one species cannot
be united, or can be united with extreme difficulty, with
the female of a second species, whilst the converse cross
can be effected with perfect facility; for this difference
in the facility of making reciprocal ci*osses, and in the
fertility of their offspring, must be attributed either to
the male or female element in the first species having
been differentiated with reference to the sexual element
of the second species in a higher degree than in the con-
verse case. In so complex a subject as Hybridism it is
of considerable importance thus to arrive at a definitive
conclusion, namely, that the sterility which almost in-

Chap. XIX. HYBRIDISM. 225

variably follows the union of distinct species depends
exclusively on differences in their sexual constitution.

On the principle which makes it necessary for man,
whilst he is selecting and improving his domestic varieties,
to keep them sepai-ate, it would clearly be advantageous
to varieties in a state of nature, that is to incipient spe-
cies, if they could be kept from blending, either through
sexual aversion, or by becoming mutually sterile. Hence
it at one time appeared to me probable, as it has to others,
that this sterility might have been acquired through
natural selection. On this view we must suppose that a
shade of lessened fertility first spontaneously appeared,
like any other modification, in certain individuals of a
species when crossed with other individuals of the same
species ; and that successive slight degrees of infertility,
from being advantageous, were slowly accumulated. This
appeal's all the more probable, if we admit that the struc-
tural differences between the forms of dimorphic and tri-
m orphic plants, as the length and curvature of the pistil,
&c, have been co-adapted through natural selection ; for if
this be admitted, we can hardly avoid extending the same
conclusion to their mutual infertility. Sterility moreover
has been acquired through natural selection for other and
widely different purposes, as with neuter insects in refer-
ence to their social economy. In the case of plants, the
flowers on the circumference of the truss in the guelder-
rose ( Viburnum opulus) and those on the summit of the
spike in the feather-hyacinth (JTuscari comosum) have been
rendered conspicuous, and apparently in consequence ste-
rile, in order that insects might easily discover and visit
the other flowers. But when we endeavour to apply the
principle of natural selection to the acquirement by dis-
tinct species of mutual sterility, we meet with great diffi-
culties. In the first place, it may be remarked that sepa-
rate regions are often inhabited by groups of species or
by single species, which when brought together and

226 HYBKIDISM. Chap. XIX.

crossed are found to be more or less sterile ; now it could
clearly have been of no advantage to such separated spe-
cies to have been rendered mutually sterile, and conse-
quently this could not have been effected through natural
selection ; but it may perhaps be argued, that, if a species
were rendered sterile with some one compatriot, sterility
with other species would follow as a necessary conse-
quence. In the second place, it is as much opposed to
the theory of natural selection, as to the theory of special
creation, that in reciprocal crosses the male element of
one form should have been rendered utterly impotent on
a second form, whilst at the same time the male element
of this second form is enabled freely to fertilise the first
form ; for this peculiar state of the reproductive system
could not possibly be advantageous to either species.

In considering the probability of natural selection hav-
ing come into action in rendering species mutually sterile,
one great difficulty will be found to lie in the existence
of many graduated steps from slightly lessened fertility
to absolute sterility. It may be admitted, on the prin-
ciple above explained, that it would profit an incipient
species if it were rendered in some slight degree sterile
when crossed with its parent form or with some other
variety ; for thus fewer bastardised and deteriorated off-
spring would be produced to commingle their blood with
the new species in process of formation. But he who
will take the trouble to reflect on the steps by which this
first degree of sterility could be increased through natural
selection to that higher degree which is common to so
many species, and which is universal with species which
have been differentiated to a generic or family rank, will
find the subject extraordinarily complex. After mature
reflection it seems to me that this could not have been
effected through natural selection ; for it could have been
of no direct advantage to an individual animal to breed
badly with another individual of a different variety, and
thus leave few offspring ; consequently such individuals

Chap. XIX. HYBRIDISM. 227

could not have been preserved or selected. Or take the case
ot* two species which in their present state, -when crossed,
produce few and sterile offspring ; now, what is there
which could favour the survival of those individuals which
happened to be endowed in a slightly higher degree Avith
mutual infertility ami which thus approached by one
small step towards absolute sterility? yet an advance of
this kind, if the theory of natural selection be brought
to bear, must have incessantly occurred with many spe-
cies, for a multitude are mutually quite barren. With
sterile neuter insects we have reason to believe that modi-
fications in their structure have been slowly accumulated
by natural selection, from an advantage having been thus
indirectly given to the community to which they be-
longed over other communities of the same species ; but
an individual animal, if rendered slightly sterile when
crossed with some other variety, would not thus in itself
gain any advantage, or indirectly give any advantage to
its nearest relatives or to other individuals of the same
variety, leading to their preservation. I infer from these
considerations that, as far as animals are concerned, the
various degrees of lessened fertility which occur with
species when crossed cannot have been slowly accumu-
lated by means of natural selection.

.With plants, it is possible that the case may be some-
what different. With many kinds, insects constantly
carry pollen from neighbouring plants to the stigmas of
each flower; and with some species this is effected by
the wind. Now, if the pollen of a variety, when depos-
ited on the stigma of the same variety, should become
by spontaneous variation in ever so slight a degree pre-
potent over the pollen of other varieties, this would cer-
tainly be an advantage to the variety ; for its own pollen
would thus obliterate the effects of the pollen of other
varieties, and prevent deterioration of character. And
the more prepotent the variety's own pollen could be
rendered through natural selection, the greater the ad-

228 HYBKIDISM. Chap. XIX.

vantage would be. We know from the researches of
Gartner that, with species which are mutually sterile, the
pollen of each is always prepotent on its own stigma
over that of the other species; but we do not know
whether this prepotency is a consequence of the mutual
sterility, or the sterility a consequence of the prepotency.
If the latter view be correct, as the prepotency became
stronger through natural selection, from being advan-
tageous to a species in process of formation, so the ste-
rility consequent on prepotency would at the same time
be augmented ; and the final result would be various de-
grees of sterility, such as occurs with existing species.
This view might be extended to animals, if the female
before each birth received several males, so that the sex-
ual element of the prepotent male of her own variety
obliterated the effects of the access of previous males
belonging to other varieties ; but we have no reason to
believe, at least with terrestrial animals, that this is the
case ; as most males and females pair for each birth, and
some few for life.

On the whole we may conclude that with animals the
sterility of crossed species has not been slowly augmented
through natural selection ; and as this sterility follows
the same general laws in the vegetable as in the animal
kingdom, it is improbable, though apparently possible,
that with plants crossed species should have been ren-
dered sterile by a different process. From this consid-
eration, and remembering that species which have never
co-existed in the same country, and Avhich therefore could
not have received any advantage from having been ren-
dered mutually infertile, yet are generally sterile when
crossed ; and bearing in mind that in reciprocal crosses
between the same two species there is sometimes the
widest difference in their sterility, we must give up the
belief that natural selection has come into play.

As species have not been rendered mutually infertile
through the accumulative action of natural selection, and

Chap. XIX. HYBKIDISM. 229

as we may safely conclude, from the previous as well as
from other and more general considerations, that they
have not been endowed through an act of creation with
this quality, we must infer that it has arisen incidentally
during their slow formation in connection with other and
unknown changes in their organisation. By a quality
arising incidentally, I refer to such cases as different spe-
cies of animals and plants being differently affected by
poisons to which they are not naturally exposed ; and this
difference in susceptibility is cleai-ly incidental on other
and unknown differences in their organisation. So again
the capacity in different kinds of trees to be grafted on
each other, or on a third species, differs much, and is of
no advantage to these trees, but is incidental on structu-
ral or functional differences in their woody tissues. We
need not feel surprise at sterility incidentally resulting
from crosses between distinct species, — the modified de-
scendants of a common progenitor, — when we bear in
mind how easily the reproductive system is affected by
various causes — often by extremely slight changes in the
conditions of life, by too close interbreeding, and by
other agencies. It is well to bear in mind such cases, as
that of the Passiflora alata, which recovered its self-fertili-
ty from being grafted on a distinct species — the cases of
plants which normally or abnormally are self-impotent, but
can readily be fertilised by the pollen of a distinct species
— and lastly the cases of individual domesticated animals
which evince towards each other sexual incompatibility.

We now at last come to the immediate point under
discussion : how is it that, with some few exceptions in
the case of plants, domesticated varieties, such as those
of the dog, fowl, pigeon, several fruit-trees, and culinary
vegetables, which differ from each other in external cha-
racters more than many species, are perfectly fertile when
crossed, or even fertile in excess, whilst closely allied
species are almost invariably in some degree sterile?

230 HYBRIDISM. Chap. XIX.

We can, to a certain ^ttent, give a satisfactory answer
to this question. Passing over the fact that the amount
of external difference between two species is no sure
guide to their degree of mutual sterility, so that similar
differences in the case of varieties would be no sure guide,
we know that with species the cause lies exclusively in
differences in their sexual constitution. Now the condi-
tions to which domesticated animals and cultivated plants
have been subjected, have had so little tendency towards
modifying the reproductive system in a manner leading
to mutual sterility, that we have good grounds for ad-
mitting the directly opposite doctrine of Pallas, namely,
that such conditions generally eliminate this tendency;
so that the domesticated descendants of species, which in
their natural state would have been in some degree sterile
when crossed, become perfectly fertile together. With
plants, so fir is cultivation from giving a tendency to-
wai'ds mutual sterility, that in several well-authenticated
cases, already often alluded to, certain species have been
affected in a very different manner, for they have become
self-impotent, whilst still retaining the capacity of fertilis-
ing, and being fertilised by, distinct species. If the
Pallasian doctrine of the elimination of sterility through
long-continued domestication be admitted, and it can
hardly be rejected, it becomes in the highest degree im-
probable that similar circumstances should commonly
both induce and eliminate the same tendency ; though in
certain cases, with species having a peculiar constitution,
sterility might occasionally be thus induced. Thus, as
I believe, we can understand why with domesticated
animals varieties have not been produced which are
mutually sterile; and why with plants only a few such
cases have been observed, namely, by Gartner, with
certain varieties of maize and verbascum, by other ex-
perimentalists with varieties of the gourd and melon, and
by Kolreuter with one kind of tobacco.
i With respect to varieties which have originated in a

Chap. XIX. . HYBRIDISM. 231

state of nature, it is almost hopeless to expect to prove by-
direct evidence that they have been rendered mutually
sterile ; for if even a trace of sterility could be detected,
such varieties would at once be raised by almost every
naturalist to the rank of distinct species. If, for instance,
Gartner's statement were fully confirmed, that the blue
and red-flowered forms of the pimpernel (AnagaUis ar-
vensis) are sterile when crossed, I presume that all the
botanists who now maintain on various grounds that
these two forms are merely fleeting varieties, would at
once admit that they were specifically distinct.

The real difficulty in our present subject is not, as it
appears to me, why domestic varieties have not become
mutually infertile when crossed, but why this has so gen-
erally occurred with natural varieties as soon as they have
been modified in a sufficient and permanent degree to
take rank as species. We are far from precisely knowing
the cause ; nor is this surprising, seeing how profoundly
ignorant we are in regard to the normal and abnormal
action of the reproductive system. But we can see that
species, owing to their struggle for life with numerous
competitors, must have been exposed to more uniform
conditions during long periods of time, than have been
domestic varieties; and this may well make a wide dif-
ference in the result. For we know how commonly wild
animals and plants, when taken from their natural con-
ditions and subjected to captivity, are rendered sterile ;
and the reproductive functions of organic beings which
have always lived and been slowlymodified under natural
conditions would probably in like manner be eminently
sensitive to the influence of an unnatural cross. Domes-
ticated productions, on the other hand, which, as shown
by the mere fact of their dometiscation, were not origin-
ally highly sensitive to changes in their conditions of
life, and which can now generally resjst with undiminished
fertility repeated changes of conditions, might be ex-
pected to produce varieties, which would be little liable

232 HYBRIDISM. Chap. XIX.

to have their reproductive powers injuriously affected by
the act of crossing with other varieties which had origi-
nated in a like manner.

Certain naturalists have recently laid too great stress,
as it appears to me, on the difference in fertility between
varieties and species when crossed. Some allied species
of trees cannot be grafted on each other, — all varieties
can be so grafted. Some allied animals are affected in a
very different manner by the same poison, but with
varieties no such case until recently was known, but
now it has been proved that immunity from certain
poisons stands in some cases in correlation with the col-
our of the hair. The period of gestation generally differs
much with distinct species, but with varieties until lately
no such difference had been observed. The time required
for the germination of seeds differs in an analogous man-
ner, and I am not aware that any differences in this re-
spect has as yet been detected with varieties. Here
we have various physiological differences, and no doubt
others could be added, between one species and another
of the same genus, which do not occur, or occur with
extreme rarity, in the case of varieties ; and these dif-
ferences are apparently wholly or in chief part inciden-
tal on other constitutional differences, just in the same
manner as the sterility of crossed species is incidental on
differences confined to the sexual system. Why, then,
should these latter differences, however serviceable they
may indirectly be in keeping the inhabitants of the same
country distinct, be thought of such paramount import-
ance, in comparison with other incidental and functional
differences ? No sufficient answer to this question can
be given. Hence the fact that the most distinct domestic
varieties are, with rare exceptions, perfectly fertile when
crossed, and produce fertile offspring, whilst closely allied
species are, with rare exceptions, more or less sterile, is not
nearly so formidable an objection as it appears at first
to the theory of the common descent of allied species.

Chap- XX. SELECTION. 233

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 — SELEC-
TION CARRIED ON BY TnE 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- VARIETY — PLANTS AS AFFECTED BY
UNCONSCIOUS SELECTION — EFFECTS OF SELECTION AS SHOWN BY
THE GREAT AMOUNT OF DIFFERENCE IN THE PARTS MOST
VALUED BY MAN.

The power of Selection, whether exercised by man, or
brought into play under nature through the struggle for
existence and the consequent survival of the fittest, abso-
lutely depends on the variability of organic beings. With-
out variability nothing can be effected ; slight individual
differences, however, suffice for the work, and are probably
the sole differences which are effective in the production
'of new species. Hence our discussion on the causes and
laws of variability ought in strict order to have preceded
our present subject, as well as the previous subjects of
inheritance, crossing, &c. ; but practically the present
arrangement has been found the most convenient. Man
does not attempt to cause variability ; though he unin-
tentionally effects this by exposing organisms to new
conditions of life, and by crossing breeds already formed.
But variability being granted, he works wonders. Unless

234 SELECTION. Chap. XX.

some degree of selection be exercised, the free commin-
gling of the individuals of the same variety soon oblite-
rates, as Ave have previously seen, the slight differences
which may arise, and give3 to the whole body of indivi-
duals uniformity of character. In separated districts, long-
continued exposure to different conditions of life may
perhaps produce new races without the aid of selection ;
but to this difficult subject of the direct action of the
conditions of life we shall in a future chapter recur.

When animals or plants are born with some conspicu-
ous and firmly inherited new character, selection is re-
duced to the preservation of such individuals, and to
the subsequent prevention of crosses ; so that nothing
more need be said on the subject. But in the great
majority of cases a new character, or some superiority
in an old character, is at first faintly pronounced, and is
not strongly inherited; and then the full difficulty of
selection is experienced. Indomitable patience, the finest
powers of discrimination, and sound judgment must be
exercised during many years. A clearly predetermined
object must be kept steadily in view. Few men are en-
dowed with all these qualities, especially with that of
discriminating very slight differences ; judgment can be
acquired only by long experience ; but if any of these
qualities be wanting, the labour of a life may be thrown
away. I have been astonished when celebrated breed-
ers, whose skill and judgment have been proved by
their success at exhibitions, have shown me their ani-
mals, which appeared all alike, and have assigned their .
reasons for matching this and that individual. The im-
portance of the great principle of Selection mainly lies
in this power of selecting scarcely appreciable differ-
ences, which nevertheless are found to be transmissible,
and which can be accumulated until the result is made
manifest to the eyes of every beholder.

The principle of selection may be conveniently di-
vided into three kinds. Methodical selection is that

Chap. XX. METHODICAL SELECTION. 235

which guides a man who .systematically endeavours to
modify a breed according to some predetermined stand-
ard. Unconscious selection is that which follows from
men naturally preserving the most valued and destroying
the less valued individuals, without any thought of
altering the breed; and undoubtedly this process slowly
works great changes. Unconscious selection graduates
into methodical, and only extreme cases can be distinctly
separated ; for he who preserves a useful or perfect
animal will generally breed from it with the hope of
getting offspring of the same character; but as long as
he has not a predetermined purpose to improve the
breed, he may be said to be selecting unconsciously.1
Lastly, we have JVatural selection, which implies that
the individuals which are best fitted for the complex,
and in the course of ages changing conditions to which
they are exposed, generally survive and procreate their
kind. With domestic productions, with which alone we
are here strictly concerned, natural selection comes to a
certain extent into action, independently of, and even in
opposition to, the will of man.

Methodical Selection. — What man has effected within
recent times in England by methodical selection is clear-
ly shown by our exhibitions of improved quadrupeds
and fancy birds. With respect to cattle, sheep, and
pigs, we owe their great improvement to a long series
of well-known names — Bakewell, Colling, Ellman, Bates,
Jonas Webb, Lords Leicester and Western, Fisher Hobbs,
and others. Agricultural writers are unanimous on the
power of selection : any number of statements to this
effect could be quoted ; a few will suffice. Youatt, a

1 The term unconscious selection has that when the wind heaps up sand-dunes

been objected to as a contradiction : but it sifts and unconsciously seUcts from

see some excellent observations on this the gravel on the beach grains of sand

head by Prof. Huxley (' Nat. Hist. Re- of equal size,
view,' Oct. K6i, p. 578), who remarks

236 SELECTION. Chap. XX.

sagacious and experienced observer, writes,2 the princi-
2>le of selection is " that which enables the agriculturist,
not only to modify the character of his flock, but to
change it altogether." A great breeder of shorthorns s
says, " In the anatomy of the shoulder modern breeders
" have made great improvements on the Ketton short-
" horns by correcting the defect in the knuckle or shoul-
" der-joint, and by laying the top of the shoulder more
" snugly into the crop, and thereby filling up the hollow

" behind it The eye has its fashion at different

" periods ; at one time the eye high and outstanding
" from the head, and at another time the sleepy eye sunk
" into the head ; but these extremes have merged into
" the medium of a full, clear, and prominent eye with a
" placid look."

Again, hear what an excellent judge of pigs4 says:
" The legs should be no longer than just to prevent the
" animal's belly from trailing on the ground. The leg
" is the least profitable portion of the hog, and we there-
" fore require no more of it than is absolutely necessary
" for the support of the rest." Let any one compare
the wild-boar with any improved breed, and he will see
how effectually the legs have been shortened.

Few persons, except breeders, are aware of the syste-
matic care taken in selecting animals, and of the neces-
sity of having a clear and almost prophetic vision into
futurity. Lord Spencer's skill and judgment were well
known ; and he writes,6 " It is therefore very desirable,
"before any man commences to breed either cattle or
" sheep, that he should make up his mind to the shape
" and qualities he wishes to obtain, and steadily pursue this
" object." Lord Somerville, in speaking of the marvellous
improvement of the New Leicester sheep, effected by

a Sheep, 1S3S, p. 60. * II. D. Richardson on Pigs, 1S47, p.

s Mr. J. Wright on Shorthorn Cattle, 44.

in 'Journal of Royal Agricult. Soc.,' vol. 6 'Journal of R. Agricult. Soc.,' vol. 1.

vii. pp. 208, 209. p. 24.

Chip. XX. METHODICAL SELECTION. 237

Bakcwell and his successors, says, " It would seem as if
they had first drawn a perfect form, and then given it
life." Youatt " urges the necessity of annually drafting
each flock, as many animals will certainly degenerate
" from the standard of excellence, which the breeder has
established in his own mind." Even with a bird of such
little importance as the canary, long ago (1780-1790)
rules were established, and a standai'd of perfection was
fixed, according to which the London fanciers tried to
breed the several sub-varieties.7 A great winner of
prizes at the Pigeon-shows,8 in describing the Short-
faced Almond Tumbler, says, " There are many first-rate
"fanciers who are particularly partial to what is called
M the goldfinch-beak, which is very beautiful ; others say,
" take a fall-size round cherry, then take a barley-corn,
" and judiciously placing and thrusting it into the cherry,
"form as it were your beak; and that is not all, for it
" will form a good head and beak, provided, as I said
"before, it is judiciously done; others take an oat; but
" as I think the goldfinch-beak the handsomest, I would
" advise the inexperienced fancier to get the head of a
" goldfinch, and keep it by him for his observation."
"Wonderfully different as is the beak of the rock-pigeon
and goldfinch, undoubtedly, as far as external shape
and proportions are concerned, the end has been nearly
gained.

Not only should our animals be examined with the
greatest care whilst alive, but as Anderson remarks,9 their
carcases should be scrutinised, "so as to breed from the
descendants of such only as, in the language of the
butcher, cut up well." The " grain of the meat" in cat-
tle, and its being well marbled with fat,10 and the greater
or less accumulation of fat in the abdomen of our shecj),

* Sheep, pp. 520, 319. the Almond Tumbler,' ia51, p. 9.

' Loudon's ' Mag. of Nat. nist.,' vol. * ' Recreations in Agriculture,' vol. ii.

viii.. 1S35, p. 618. p. 409.

" ' A Treatise on the Art of Breeding >° Youatt on Cattle, pp. 191, 227.

238 SELECTION". Chap. XX.

have be.en attended to with success. So with poultry, a
writer,11 speaking of Cochin-China fowls, which are said
to differ much in the quality of their flesh, says, "the
" best mode is to purchase two young brother cocks, kill,
" dress, and serve up one ; if he be indifferent, similarly
" dispose of the other, and try again ; if, however, he be
" fine and well-flavoured, his brother will not be amiss for
" breeding purposes for the table."

The great principle of the division of labour has been
brought to bear on selection. In certain districts 12 " the
" breeding of bulls is confined to a very limited number
" of persons, who by devoting their whole attention to
" this department, are able from year to year to furnish
"a class of bulls which are steadily improving the gene-
" ral breed of the district." The rearing and letting of
choice rams has long been, as is well known, a chief
source of profit to several eminent breeders. In parts
of Germany this principle is carried with merino sheep
to an extreme point.13 " So important is the proper selec-
"tion of breeding animals considered, that the best flock-
" masters do not trust to their own judgment, or to
" that of their shepherds, but employ persons called
" ' sheep-classifiers,' who make it their special business
" to attend to this part of the management of several
"flocks, and thus to preserve, or if possible to improve,
" the best qualities of both parents in the lambs." In
Saxony, when the lambs are weaned, each in his turn is
placed upon a table that his wool and form may be mi-
nutely observed. " The finest are selected for breeding
" and receive a first mark. When they are one year old,
"and prior to shearing them, another close examination
" of those previously marked takes place : those in which
" no defect can be found receive a second mark, and the rest

11 Ferguson, ' Prize Poultry,' 1854, p. nicle,' 1S44, p. 29.

203. 13 Simmonds, quoted in ' Gard. Chro

12 Wilson, in ' Transact. Highland nicle,' 1S55, p. 637. And for the second
Agricult. Soc.,' quoted in ' Gard. Chro- quotation, see Youatt on Sheep, p. 171.

Chap. XX. METHODICAL SELECTION. 239

" are condemned. A few months afterwards a third and
" last scrutiny is made ; the prime rams and ewes receive a
"third and final mark, but the slightest blemish is sufficient
"to cause the rejection of the animal." These sheep are
bred and valued almost exclusively for the fineness of
their wool ; and the result corresponds with the labour
bestowed on their selection. Instruments have been in-
vented to measure accurately the thickness of the fibres;
and " an Austrian fleece has been produced of which
twelve hairs equalled in thickness one from a Leicester
sheep."

Throughout the world, wdierever silk is produced, the
greatest care is besto*wed on selecting the cocoons from
which the moths for breeding are to be reared. A care-
ful cultivator " likewise examines the moths themselves,
and destroys those that are not perfect. But what more
immediately concerns us is that certain families in France
devote themselves to raising eggs for sale.15 In China,
near Shanghai, the inhabitants of two small districts have
the privilege of raising eggs for the whole surrounding
country, and that they may give up their whole time to
this business, they are interdicted bylaw from producing
silk.'6

The care which successful breeders take in matching
their birds is surprising. Sir John Sebright, whose fame
is perpetuated by the " Sebright Bantam," used to spend
" two and three days in examining, consulting, and dis-
puting with a friend which were the best of five or six
birds." " Mr. Bult, whose pouter-pigeons won so many
prizes and were exported to North America under the
charge of a man sent on purpose, told me that he always
deliberated for several days before he matched each pair.
Hence we can understand the advice of an eminent fan-

" Robinet, ' Vers a Sole,' 1<U3, p. 271. cliroat,,' torn, ix., 1S62, p. 221.
15 Quatrefages, ' Les Maladies du Ver a 17 'The Poultry Chronicle,' voL i.,

Soie,' 1S59, p. 101. ISM, p. 607.
11 M. Simon, in ' Bull, de la Soc. d'Ac-

240 SELECTION". Chap. XX

cier, who writes,18 " I would here particularly guard you
" against having too great a variety of pigeons, otherwise
" you will know a little of all, but nothing about one as
" it ought to be known." Apparently it transcends the
power of the human intellect to breed all kinds : " it is
" possible that there may be a few fanciers that have a
" good general knowledge of fancy pigeons ; but there
" are many more who labour under the delusion of sup-
" posing they know what they do not." The excellence
of one sub-variety, the Almond Tumbler, lies in the
plumage^ carriage, head, beak, and eye ; but it is too pre-
sumptuous in the beginner to try for all these points.
The great judge above quoted sa*ys, "there are some
"young fanciers who are over-covetous, who go for all
"the above five properties at once ; they have their re-
" ward by getting nothing." We thus see that breeding
even fancy pigeons is no simple art : we may smile at the
solemnity of these precepts, but he who laughs will win
no prizes.

What methodical selection has effected for our animals
is sufficiently proved, as already remarked, by our Exhi-
bitions. So greatly were the sheep belonging to some of
the earlier breeders, such as Bakewell and Lord Western,
changed, that many persons could not be persuaded that
they had not been crossed. Our pigs, as Mr. Corring-
ham remarks,19 during the last twenty years have under-
gone, through rigorous selection together with crossing,
a complete metamorphosis. The first exhibition for
poultry was held in the Zoological Gardens in 1845 ; and
the improvement effected since that time has been great.
As Mr. Baily, the great judge, remarked to me, it was
formerly ordered that the comb of the Spanish cock
should be upright, and in four or five years all good

« J. M. Eaton, ' A Treatise on Fancy 19 ' Journal Royal Agricultural Soc.,'

Pigeons,' 1852, p. xiv., and ' A Treatise vol. vi. p. 22.
on the Almond Tumbler,' 1851, p. 11.

Chap. XX. METHODICAL SELECTION. 241

birds had upright combs; it was ordered that the Polish
cock should have no comb or wattles, and now a bird
thus furnished would be at once disqualified ; beards
were ordered, and out of fifty-seven pens lately (1860)
exhibited at the Crystal Palace, all had beards. So it
has been in many other cases. But in all cases the judges
order only what is occasionally produced and what can
be improved and rendered constant by selection. The
steady increase of weight during the last few years in our
fowls, turkeys, ducks, and geese is notorious ; " six-pound
ducks are now common, whereas four pounds was former-
ly the average." As the actual time required to make
a change has not often been recorded, it may be worth
mentioning that it took Mr. "Wicking thirteen years to
put a clean white head on a almond tumbler's body, " a
triumph," says another fancier, "of which he may be
justly proud." "°

Mr. Toilet, of Betley Hall, selected cows, and especial-
ly bulls, descended from good milkers, for the sole pur-
pose of improving his cattle for the production of cheese ;
he steadily tested the milk with the lactometer, and in
eight years he increased, as I was informed by him, the
product in the pi*oportion of four to three. Here is a curi-
ous case S1 of steady but slow progress, with the end not
as yet fully attained: in 1784 a raceof silk-worms was
introduced into France, in which one hundred out of the
thousand failed to produce white cocoons ; but now, after
careful selection during sixty-five generations, the propor-
tion of yellow cocoons has been reduced to thirty-five in
the thousand.

With plants selection has been followed with the same
good results as with animals. But the process is simpler,
for plants in the great majority of cases bear both sexes.
Nevertheless, with most kinds it is necessary to take as

20 ' Poultry Chronicle,' vol. ii., 1S55, p. 21 Isid. Geoffroy St. Hilaire, ' Hist. Nat.

596. G6n.,' torn. iil. p. 254.

242 SELECTION. Chap. XX

much care to prevent crosses as with animals or unisex-
ual plants ; but with some plants, such as peas, this care
does not seem to be necessary. With all improved plants,
excepting of course those which are propagated by buds,
cuttings, &c, it is almost indispensable to examine the
seedlings and destroy those which depart from the proper
type. This is called " roguing," and is, in fact, a form
of selection, like the rejection of inferior animals. Expe-
rienced horticulturists and agriculturists incessantly urge
everyone to preserve the finest plants for the production
of seed.

Although plants often present much more conspicuous
variations than animals, yet the closest attention is gen-
erally requisite to detect each slight and favourable
change. Mr. Masters .relates 22 how " many a patient
hour was devoted," whilst he was young, to the detec-
tion of differences in peas intended for seed. Mr. Barnet 2S
remarks that the old scarlet American strawberry was
cultivated for more than a century without producing a
single variety ; and another writer observes how singu-
lar it was that when gardeners first began to attend to
this fruit it began to vary ; the truth no doubt being that
it had always varied, but that, until slight varieties were
selected and propagated by seed, no conspicuous result
was obtained. The finest shades of difference in wheat
have been discriminated and selected with almost as much
care, as we see in Colonel Le Couteur's works, as in the
case of the higher animals ; but with our cereals the pro-
cess of selection has seldom or never been long continued.

It maybe woi'th while to give a few examples of me-
thodical selection with plants ; but in fact the great im-
provement of all our anciently cultivated plants may be
attributed to selection long carried on, in part methodi-
cally, and in part unconsciously. I have shown in a for-

22 ' Gardener's Chronicle,' 1S50, p. 19S.

23 'Transact. Hort. Soc.,' vol. vi. p. 152.

Chap. XX. METHODICAL SELECTION. 243

mer chapter how the weight of the gooseberry has been
increased by systematic selection and culture. The flow-
ers of the Heartsease have been similarly increased in size
and regularity of outline. With the Cineraria, Mr. Glen-
ny 24 " was bold enough, when the flowers were ragged
"and starry and ill defined in colour, to fix a standard
" which was then considered outrageously high and im-
" possible, and which, even if reached, it was said, we
" should be no gainers by, as it would spoil the beauty of
" the flowers. He maintained that he was right ; and the
" event has proved it to be ao." The doubling of flowers
has several times been effected by careful selection : the
Rev. W. Williamson,25 after sowing during several years
seed of Anemone coro?iaria, found a plant with one addi-
tional petal ; he sowed the seed of this, and by persever-
ance in the same course obtained several varieties with
six or seven rows of petals. The single Scotch rose Avas
doubled, and yielded eight good varieties in nine or ten
years.26 The Canterbury bell {Campanula medium) was
doubled by careful selection in four generations.27 In four
years Mr. Buckman,28 by culture and careful selection,
converted parsnips, raised from wild seed, into a new and
good variety. By selection during a long course of years,
the early maturity of peas has been hastened from ten to
twenty-one days1.29 A more curious case is offered by the
beet-plant, which, since its cultivation in France, has
almost exactly doubled its yield of sugar. This has been
effected by the most careful selection ; the specific gravity
of the roots being regularly tested, and the best roots
saved for the production of seed.30

24 'Journal of Horticulture,' 1862, p. 28 ■ Gard. Chronicle,' 1862, p. 721.
8C9. 29 Dr. Anderson, in 'The Bee,' vol. vi.

25 ' Transact, Hort. Soc.,' vol. iv. p. 8S1. p. 96 ; Mr. Barnes, in ' Gard. Chronicle,'
28 'Transact. Hort. Soc.,' vol. iv. p. 1S44, p. 4T6.

2S5. so Godron, ' De l'Espece,' 1859, torn. ii.

27 Rev. W. Bromehead, in 'Gard. p. 69; 'Gard. Chronicle,' 1854, p. 258.
Chronicle,' 1S5T, p. 550.

244 SELECTION Chap. XX.

Selection by Ancient and Semi- Civilised People.

In attributing so much importance to the selection of
animals and plants, it may be objected that methodical
selection would not have been carried on during ancient
times. A distinguished naturalist considers it as absurd
to suppose that semi-civilised people should have prac-
tised selection of any kind. Undoubtedly the principle
has been systematically acknowledged and followed to a
far greater extent within the last hundred years than at
any former period, and a corresponding result has been
gained ; but it would be a great error to suppose, as we
shall immediately see, that its importance was not recog-
nised and acted on during the most ancient times, and
by semi-civilised people. I should premise that many
facts now to be given only show that care was taken in
breeding ; but when this is the case, selection is almost
sure to be practised to a certain extent. We shall here-
after be enabled better to judge how far selection, when
only occasionally carried on, by a few of the inhabitants
of a country, will slowly produce a great effect.

In a well-known passage in the thirtieth chapter of
Genesis, rules are given for influencing, as was then
thought possible, the colour of sheep ; and speckled and
dark breeds are spoken of as being kept separate. By
the time of David the fleece was likened to snow.
Youatt,31 who has discussed all the passages in relation
to breeding in the Old Testament, concludes that at this
early period " some of the best principles of breeding
must have been steadily and long pursued." It was or-
dered, according to Moses, that "Thou shalt not let thy
cattle gender with a diverse kind ; " but mules were
purchased,32 so that at this early period other nations
must have crossed the horse and ass. It is said 33 that

31 On Sheep, p. 18. 33 Mitford's 'History of Greece,' vol.

32 Volz, ' Beitrage zur Kulturge- i. p. T3.
schichte,' 1852, s. 4T.

Chap. XX. BY THE ANCIENTS. 245

Erichthonius, some generations before the Trojan war,
had many brood-mares, " which by his care and judgment
in the choice of stallions produced a breed of horses su-
perior to any in the surrounding countries." Homer
(Book v.) speaks of iEneas's horses as bred from mares
which were put to the steeds of Laomedon. Plato, in
his ' Republic,' says to Glaucus, " I see that you raise at
your house a great many dogs for the chase. Do you
take care about breeding and pairing them ? Among
animals of good blood, are there not always some which
are superior to the rest?" To which Glaucus answers
in the affirmative.3* Alexander the Great selected the
finest Indian cattle to send to Macedonia to improve the
breed.35 According to Pliny,36 King Pyrrhus had an
especially valuable breed of oxen ; and he did not suffer
the bulls and cows to come together till four years oldr
that the breed might not degenerate. Virgil, in his
Georgics (lib. iii.), gives as strong advice as any modern
agriculturist could do, carefully to select the breeding
stock ; " to note the tribe, the lineage, and the sire ;
whom to reserve for husband of the herd;" — to brand
the progeny; — to select sheep of the purest white, and
to examine if their tongues are swarthy. We have seen
that the Romans kept pedigrees of their pigeons, and this
would have been a senseless proceeding had not great
care been taken in breeding them. Columella gives de-
tailed instructions about breeding fowls : " Let the breed-
" ing hens therefore be of a choice colour, a robust body,
" square-built, full-breasted, with large heads, with up-
" right and bright-red combs. Those are believed to be
" the best bred which have five toes." 37 According to
Tacitus, the Celts attended to the races of their domestic
animals ; and Caesar states that they paid high prices to

31 Dr. Dally, translated in ' Anthropo- 36 ' History of the World,' eta. 45.

logical Review,' May, 1804, p. 101. 37 ' Gardener's Chronicle,' 1848, p. 328.

M Volz, ' Bcitriige,' &.C., 1852, s. 80.

246 SELECTION Chap. XX.

merchants for fine imported horses.38 In regard to plants,
Virgil speaks of yearly culling the largest seeds ; and
Celsus says, " where the corn and crop is but small, we
must pick out the best ears of corn, and of them lay up
our seed separately by itself." 39

Coming down the stream of time, we may be brief.
At about the beginning of the ninth century Charle-
magne expressly ordered his officers to take great care of
his stallions ; and if any proved bad or old, to forewarn
him in good time before they were put to the mai*es.40
Even in a country so little civilised as Ireland during the
ninth century, it would appear from some ancient verses,41
describing a ransom demanded by Cormac, that animals
from particular places, or having a particular character,
were valued. Thus it is said, —

Two pigs of the pigs of Mac Lir,

A ram and ewe both round and red,

I brought with me from Aengus.

I brought with me a stallion and a mare

From the beautiful stud of Manannan,

A bull and a white cow from Druim Cain.

Athelstan, in 930, received as a present from Germany,
running-horses; and he prohibited the exportation of
English horses. King John imported " one hundred cho-
sen stallions from Flanders."42 On June 16th, 1305, the
Prince of Wales wrote to the Archbishop of Canterbury,
begging for the loan of any choice stallion, and promis-
ing its return at the end of the season.43 There are
numerous records at ancient periods in English history
of the importation of choice animals of various kinds, and
of foolish laws against their exportation. In the reigns
of Henry VII. and VIII. it was ordered that the magis-

38 Reynier, ' De l'Economie des Celtes,' ufactured Animal Remains,' &c, 1860,

ISIS, pp. 4S7, 503. p. 11.

89 Le Couteur on Wheat, p. 15. 42 Col. Hamilton Smith, ' Nat. Libra-

40 Michel, ' Des Haras,' 1861, p. 84. ry,' vol. xii., Horses, pp. 135, 140.

41 Sir W. Wilde, ' an Essay on Unman- 43 Michel, ' Des Haras,' p. 90.

Chap XX. BY THE ANCIENTS. 247

trates, at Michaelmas, should scour the heaths and com-
mons, and destroy all mares beneath a certain size."
Some of our earlier kings passed laws against the slaugh-
tering rams of any good breed before they were seven
years old, so that they might have time to breed. In
Spain Cardinal Ximenes issued, in 1509, regulations on the
selection of good rams for breeding.45

The Emperor Akbar Khan before the year 1600 is said
to have " wonderfully improved " his pigeons by crossing
the breeds ; and this necessarily implies careful selection.
About the same period the Dutch attended with the
greatest care to the breeding of these birds. Belon in
1555 says that good managers in France examined the
colour of their goslings in order to get geese of a white
colour and better kinds. Markkam in 1631 tells the
breeder " to elect the largest and goodliest conies," and
enters into minute details. Even with respect to seeds of
plants for the flower-garden, Sir J. Hanmer writing about
the year 166046 says, in "choosing seed, the best seed is
the most weighty, and is had from the lustiest and most
vigorous stems ;" and he then gives rules about leaving
only a few flowers on plants for seed ; so that even such
details were attended to in our flower-gardens two hun-
dred years ago. In order to show that selection has
been silently carried on in places where it would not
have been expected, I may add that in the middle of the
last century, in a remote part of North America, Mr.
Cooper improved by careful selection all his vegetables,
" so that they were greatly superior to those of any other
" person. When his radishes, for instance, are fit for use,
" he takes ten or twelve that he most approves, and plants
" them at least 100 yards from others that blossom at the

44 Mr. Baker, 'History of the Horse,' the ancient selection of sheep ; and is
Veterinary, vol. xiii. p. 4'23. my authority for rams not being killed

45 M. l'Abb6 Carlier, in 'Journal de young in England.

Physique,' vol. xxiv., 1784, p. 181 : this 48 ' Gardener's Chronicle,' 1S43, p. 3S9.
memoir contains much information on

248 SELECTION Chap. XX.

" same time. In the same manner he treats all his other
"plants, varying the circumstances according to their
" nature."47

In the great work on China published in the last cen-
tury by the Jesuits, and which is chiefly compiled from
ancient Chinese encyclopaedias, it is said that with sheep
" improving the breed consists in choosing with particular
" care the lambs which are destined for propagation, in
" nourishing them well, and in keeping the flocks sepa-
" rate." The same principles were applied by the Chinese
to various plants and fruit-trees.48 An imperial edict re-
commends the choice of seed of remarkable size ; and
selection was practised even by imperial hands, for it is
said that the Ya-mi, or imperial rice, was noticed at an*
ancient period in a field by the Emperor Khang-hi, was
saved and cultivated in his garden, and has since become
valuable from being the only kind which will grow north
of the Great Wall.49 Even with flowers, the tree preony
(P. moutan) has been cultivated, according to Chinese
traditions, for 1400 years ; between 200 and 300 varieties
have been raised, which are cherished as tulips formerly
were by the Dutch.50

Turning now to semi-civilised people and to savages :
it occurred to me, from what I had seen of several parts
of South America, where fences do not exist, and where
the animals are of little value, that there would be abso-
lutely no care in breeding or selecting them ; and this to
a large extent is true. Roulin," however, describes in
Colombia a naked race of cattle, which are not allowed
to increase, on account of their delicate constitution.
According to Azara 52 horses are often born in Paraguay

47 Communications to Board of Agri- see ' Hue's Chinese Empire,' p. 311.
culture, quoted in Dr. Darwin's ' Phyto- 60 Anderson, in ' Linn. Transact.,' vol.
logia,' 1S00, p. 451. . xii. p. 253.

48 ' Memoire sur les Chinois,' 17S6, 6' 'Mem. de l'Acad.' (divers savans),
torn. xi. p. 55; torn. v. p. 507. torn, vi., 1835, p. 333.

49 * Recherches sur l'Agriculture des sa ' Des Quadrupedes du Paraguay,'
Chinois,' par L. D'Hervey-Saint-Denys, 1801, torn, ii, p. 333, 371.

1850, p. 229. With respect to Khang-hi,

Chap. XX. BY SEMI-CIVILISED PEOPLE. 249

with curly hair; but, as the natives do not like them,
they are destroyed. On the other hand, Azara states
that a hornless bull, born in IV TO, was preserved and pro-
pagated its race. I was informed of the existence in
Banda Oriental of a breed with reversed hair; and the
extraordinary niata cattle first appeared and have since
been kept distinct in La Plata. Hence certain conspi-
cuous variations have been preserved, and others have
been habitually destroyed, in these countries, which are
so little favourable for careful selection. We have also
seen that the inhabitants sometimes introduce cattle on
their estates to prevent the evil effects of close inter-
breeding. On the other hand, I have heard on reliable
authority that the Gauchos of the Pampas never take any
pains in selecting the best bulls or stallions for breeding ;
and this probably accounts for the cattle and horses
being remarkably uniform in character throughout the
immense range of the Argentine republic.

Looking to the Old World, in the Sahara Desert " The
" Touareg is as. careful in the selection of his breeding
" Mahari (a fine race of the dromedary) as the Arab is in
" that of his horse. The pedigrees are handed down, and
"many a dromedary can boast a genealogy far longer
" than the descendants of the Darley Arabian." b3 Ac-
cording to Pallas the Mongolians endeavour to breed the
Yaks or horse-tailed buffaloes with white tails, for these
are sold to the Chinese mandarins as fly-flappers; and
Moorcroft, about seventy years after Pallas, found that
white-tailed animals were still selected for breeding.64
. We have seen in the chapter on the Dog that savages
in different parts of North America and in Guiana cross
their dogs with wild Canidae, as did the ancient Gauls,
according to Pliny. This was done to give their dogs

63 ' The Great Sahara,' by the Rev. n. 17T7, p. 249; Moorcroft and Trebeck,
B. Tristram, I960, p. 208. 'Travels in the Himalayan Provinces,'

" Pallas, ' Act. Acad. St. Petersburg,' 1841. .

250 SELECTION Chap. XX.

strength and vigour, in the same way as the keepers in
large warrens now sometimes cross their ferrets (as I
have been informed by Mr. Yarrell) with the wild pole-
cat, " to give then more devil." According to Varro,
the wild ass was formerly caught and crossed with the
tame animal to improve the breed, in the same manner as
at the present day the natives of Java sometimes drive
their cattle into the forests to cross with the wild Ban-
teng (Bos sondaicus).6* In Northern Siberia, among the
Ostyaks the dogs vary in markings in different districts,
but in each place they are spotted black and white in a
remarkably uniform manner ; B6 and from this fact alone
we may infer careful breeding, more especially as the
dogs of one locality are famed throughout the country
for their superiority. I have heard of certain tribes of
Esquimaux who take pride in their teams of dogs being
uniformly coloured. In Guiana, as Sir R. Schomburgk
informs me,67 the dogs of the Turuma Indians are highly
valued and extensively bartered : the price of a good one
is the same as that given for a wife: they are kept in a
sort of cage, and the Indians "take great care when the
female is in season to prevent her uniting with a dog of
an inferior description." The Indians told Sir Robert
that, if a dog pi-oved bad or useless, he was not killed,
but was left to die from sheer neglect. Hardly any na-
tion is more barbarous than the Fuegians, but I hear
from Mr. Bridges, the Catechist to the Mission, that,
" when these savages have a large, strong, and active
" bitch, they take care to put her to a fine dog, and even
" take care to feed her well, that her young may be strong
" and well favoured."

In the interior of Africa, negroes, who have not associ-
ated with white men, show great anxiety to improve their

65 Quoted from Raffles, in the 'Indian translat., vol. i. p. 453.

Field,' 1859, p. 196: for Varro, see Pal- 67 See also 'Journal of R. Geograph.

las, ut supra. Soc.,' vol. xiii. part i. p. 65.

68 Erman's 'Travels in Siberia,' Eng.

Chap. XX. BY SEMI-CIYILISED PEOPLE. 251

animals : they " always choose the larger and strong-
er males for stock:" the Malakolo were much pleased
at Livingstone's promise to send them a bull, and some
Bakalolo carried a live cock all the way from Loanda
into the interior.68 Further south on the same continent,
Andersson states that he has known a Damara give two
fine oxen for a dog which struck his fancy. The Damaras
take great delight in having whole droves of cattle of the
same colour, and they prize their oxen in proportion to
the size of their horns. " The Namaquas have a perfect
" mania for a uniform team ; and almost all the people of
" Southern Africa value their cattle next to their women,
" and take a pride in possessing animals that look high-
" bred." " They rarely or never make use of a handsome
" animal as a beast of burden." 69 The power of dis-
crimination which these savages possess is wonderful,
and they can recognise to which tribe any cattle belong.
Mr. Andersson further informs me that the natives fre-
quently match a particular bull with a particular cow.

The most curious case of selection by semi-civilised
people, or indeed by any people, which I have found re-
corded, is that given by Garcilazo de la Vega, a descen-
dant of the Incas, as having been practised in Peru before
the country was subjugated by the Spaniards.60 The
Incas annually held great hunts, when all the wild ani-
mals were driven from an immense circuit to a central
point. The beasts of prey were first destroyed as inju-
rious. The wild Guanacos and Vicunas were sheared ;
the old males and females killed, and the others set at
liberty. The various kinds of deer were examined ; the
old males and females were likewise killed ; " but the
young females, with a certain number of males, selected

69 Livingstone's ' First Travels,' pp. S9 Andersson's ' Travels in South Af-

191,439, 565: see also 'Expedition to rica,' pp. 232, 318, 319.

the Zambesi,' 1855, p. 495, for an analo- «° Dr. Vavasseur, in ' Bull, de la Soc.

gous case respecting a good breed of d'Acclunat.,' torn, viii., 1SC1, p. 136.
goats.

252 SELECTION Chap. XX.

from the most beautiful and strong," were given their
freedom. Here, then, we have selection by man aiding
natural selection. So that the Incas followed exactly the
reverse S}rstem of that which our Scottish sportsmen are
accused of following, namely, of steadily killing the finest
stags, thus causing the whole race to degenerate.61 In
regard to the domesticated llamas and alpacas, they were
separated in the time of the Incas according to colour ;
and if by chance one in a flock is born of the wrong
colour, it was eventually put into another flock.

In the genus Auchenia there are four forms, — the Gua-
naco and Vicuna, found wild and undoubtedly distinct
species ; the Llama and Alpaca, known only in a domes-
ticated condition. These four animals appear so different,
that most professed naturalists, especially those who have
studied these animals in their native country, maintain
that they are specifically distinct, notwithstanding that
no one pretends to have seen a wild llama or alpaca. Mr.
Ledger, however, who has closely studied these animals
both in Peru and during their exportation to Australia,
and who has made many experiments on their propaga-
tion, adduces arguments 62 which seem to me conclusive,
that the llama is the domesticated descendant of the
guanaco, and the alpaca of the vicuna. And now that
we know that these animals many centuries ago were
systematically bred and selected, there is nothing sur-
prising in the great amount of change which they have
undergone.

It appeared to me at one time probable that, though
ancient and semi-civilised people might have attended to
the improvement of their more useful animals in essential
points, yet that they would have disregarded unimportant
characters. But human nature is the same throughout
the world : fashion everywhere reigns supreme, and man

81 ' The Natural History of Dee Side,' 6a ' Bull de la Soc. d'Acclimat.,' torn.

1S00, p. 476. vii., 1S60, p. 457.

Chip. XX. OF TRIFLING CHARACTERS. 253

is ajit to value whatever he may chance to possess. We
have seen that in South America the niata cattle, which
certainly are not made useful by their shortened faces
and upturned nostrils, have been preserved. The Dama-
ras of South Africa value their cattle for uniformity of
colour and enormously long horns. The Mongolians
value their yaks for their white tails. And I shall now
show that there is hardly any peculiarity in our most
useful animals which, from fashion, superstition, or some
other motive, has not been valued, and consequently pre-
served. With respect to cattle, " an early record," ac-
cording to Youatt," speaks of a hundred " white cows
" with red ears being demanded as a compensation by the
" princes of North and South Wales. If the cattle were
" of a dark or black colour, 150 were to be presented."
So that colour was attended to in Wales before its sub-
jugation by England. In Central Africa, an ox that
beats the ground with its tail is killed; and in South
Africa some of the Damaras will not eat the flesh of a
spotted ox. The Kaffirs value an animal with a musical
voice; and " at a sale in British Kaffraria the low of a
" heifer excited so much admiration that a sharp compe-
" tition sprung up for her possession, and she realised a
" considerable price." 61 With respect to sheep, the Chi-
nese prefer rams without horns ; the Tartars prefer them
with spirally wound horns, because the hornless are
thought to lose courage.68 Some of the Damaras will
not eat the flesh of hornless sheep. In regard to horses,
at the end of the fifteenth century animals of the colour
described as Mart pomme were most valued in France.
The Arabs have a proverb, " Never buy a horse with four
white feet, for he carries his shroud with him ;" 6S the
Arabs, also, as we have seen, despise dun-coloured horses.

83 ' Cattle,' p. 43. see ' Quarterly Review,' 18C0, p. 189.

** Livingstone's Travels, p. 5T6 ; An 65 ' Memoire sur les Chinois' (by the

dersson, 'Lake Xgami,' 1S56, p. 222. Jesuits), 17S6, torn. xi. p. 57.
With respect to the sale in Kaffraria, ™ F. Michel, ' Des Haras,' pp. 47, 50.

254 SELECTION". Chap. XX.

So with dogs, Xenophon and others at an ancient period
were prejudiced in favour of certain colours; and " white
or slate-coloured hunting-dogs were not esteemed." "

Turning to poultry, the old Roman gourmands thought
that the liver of a white goose was the most savoury. In
Paraguay black-skinned fowls are kept because they are
thought to be more productive, and their flesh the most
proper for invalids.68 In Guiana, as I am informed by
Sir R. Schomburgk, the aborigines will not eat the flesh
or eggs of the fowl, but two races are kept distinct merely
for ornament. In the Philippines, no less than nine sub-
varieties of the game cock are kept and named, so that
they must be separately bred.

At the present time in Europe, the smallest peculiari-
ties are carefully attended to in our most useful animals,
either from fashion, or as a mark of purity of blood.
Many examples could be given, two will suffice. " In the
" Western counties of England the prejudice against a
" white pig is nearly as strong as against a black one in
" Yorkshire." In one of the Berkshire sub-breeds, it is
4said, " the white should be confined to four white feet, a
" white spot between the eyes, and a few white hairs be-
" hind each shoulder." Mr. Saddler possessed "three
" hundred pigs, every one of which was marked in this
" manner." 69 Marshall, towards the close of the last cen-
tury, in speaking of a change in one of the Yorkshire
breeds of cattle, says the horns have been considerably
modified, as " a clean, small, sharp horn has been fashion-
able for the last twenty years." 70 In a part of Germany
the cattle of the Race de Gfoehl are valued for many
good qualities, but they must have horns of a particular
curvature and tint, so much so that mechanical means
are applied if they take a wrong direction ; but the in-

67 Col. Hamilton Smith, Dogs, in ' Nat. 69 Sidney's edit, of Vouatt, 1860, pp.

Lib.,' vol. x. p. 103. 24, 25.

69 Azara ' Quadrupedes du Paraguay,' 70 ' Rural Economy of Yorkehire, toL

torn li. p. 324. ii. p. 1S2.

Chap. XX. UNCONSCIOUS SELECTION. 255

habitants " consider it of the highest importance that
" the nostrils of the bull should be flesh-colored, and the
" eyelashes light ; this is an indispensable condition. A
" calf with blue nostrils would not be purchased, or pur-
" chased at a very low price." 7I Therefore let no man
say that any point or character is too trifling to be
methodically attended to and selected by breeders.

Unconscious /Selection. — By this term I mean, as already
more than once explained, the preservation by man of the
most valued, and the destruction of the least valued in-
dividuals, without any conscious intention on his part of
altering the breed. It is difficult to offer direct proofs
of the results which follow from this kind of selection ;
but the indirect evidence is abundant. In fact, except that
in the one case man acts intentionally, and in the other
unintentionally, there is little difference between metho-
dical and unconscious selection. In both cases man pre-
serves the animals which are most useful or pleasing to
him, and destroys or neglects the others. But no doubt
a far more rapid result follows from methodical than
from unconscious selection. The " roguing" of plants by
gardeners, and the destruction by law in Henry VIII. 's
reign of all under-sized mares, are instances of a process
the reverse of selection in the ordinary sense of the word,
but leading to the same general result. The influence of
the destruction of individuals having a particular character
is well shown by the necessity of killing every lamb with
a trace of black about it, in order to keep the flock
white; or again, by the effects on the average height of
the men of France of the destructive wars of Napoleon,
by which many tall men were killed, the short ones being
left to be the fathers of flimilies. This at least is the con-
clusion of those who have closely studied the subject of
the conscription ; and it is certain that since Napoleon's

71 Moll et Gayot, ' Du Bceuf,' 1860, p. 517.

256 SELECTION". Chap. XX.

time the standard for the army has been lowered two or
three times.

Unconscious selection so blends into methodical that
it is scarcely" possible to separate them. When a fancier
long ago first happened to notice a pigeon with an un-
usually short beak, or one with the tail-feathers unusually
developed, although he bred from these birds with the
distinct intention of propagating the variety, yet he
could not have intended to make a short-faced tumbler
or a fantail, and was far from knowing that he had made
the first step towards this end. If he could have seen
the final result, he would have been struck with as-
tonishment, but, from what we know of the habits of
fanciers, probably not with admiration. Our English
carriers, barbs, and short- faced tumblers have been greatly
modified in the same manner, as we may infer both from
the historical evidence given in the chapters on the Pi-
geon, and from the comparison of birds brought from dis-
tant countries.

So it has been with dogs ; our present fox-hounds dif-
fer from the old English hound ; our greyhounds have
become lighter; the wolf-dog, which belonged to the
greyhound class, has become extinct ; the Scotch deer-
hound has been modified, and is now rare. Our bulldogs
differ from those which were formerly used for baiting
bulls. Our pointers and Newfoundlands do not closely
resemble any native dog now found in the countries
whence they were brought. These changes have been
effected partly by crosses ; but in every case the result
has been governed by the strictest selection. Neverthe-
less there is no reason to suppose that man intentionally
and methodically made the breeds exactly what they
now are. As our horses became fleeter, and the country
more cultivated and smoother, fleeter fox-hounds were
desired and produced, but probably without any one
distinctly foreseeing what they would become. Our
pointers and setters, the latter almost certainly descended

Chap. XX UNCONSCIOUS SELECTION. 257

from large spaniels, have been greatly modified in ac-
cordance with fashion and the desire for increased speed.
Wolves have become extinct, deer have become rarer,
bulls are no longer baited, and the corresponding breeds
of the dog have answered to the change. But we may
feel almost sure that when, for instance, bulls were no
longer baited, no man said to himself, I will now breed
my dogs of smaller size, and thus create the present race.
As circumstances changed, men unconsciously and slowly
modified their course of selection.

With race-horses selection for swiftness has been fol-
lowed methodically, and our horses can now easily beat
their progenitors. The increased size and different ap-
pearance of the English race-horse led a good observer in
India to ask, " Could any one in this year of 1856, looking
at our race-horses, conceive that they were the result of
the union of the Arab horse and the African mare ? " "
This change has, it is probable, been largely effected
through unconscious selection, that is, by the general
wish to breed as fine horses as possible in each generation,
combined with training and high feeding, but without
any intention to give to them their present appearance.
According to Youatt,73 the introduction in Oliver Crom-
Avell's time of three celebrated Eastern stallions speedily
affected the English breed ; " so that Lord Harleigh, one
of the old school, complained that the great horse was
fast disappearing." This is an excellent proof how care-
fully selection must have been attended to ; for without
such care, all traces of so small an infusion of Eastern
blood would soon have been absorbed and lost. Not-
withstanding that the climate of England has never been
esteemed particularly favourable to the horse, yet long-
continued selection, both methodical and unconscious,
together with that 'practised by the Arabs during a still

77 ' The India Sporting Review,' vol. ii. p. 1S1 ; ' The Stud Farm,' by Cecil, p. 58.
73 ' The Horse,' p. 22.

258 SELECTION. Chap. XX.

longer and earlier period, has ended in giving us the
best breed of horses in the world. Macaulay 74 remarks,
"Two men whose authority on such subjects was held in
"great esteem, the Duke of Newcastle and Sir John
"Fen wick, pronounced that the meanest hack ever ini-
" ported from Tangier would produce a finer progeny
" than could be expected from the best sire of our na-
" tive breed. They would not readily have believed that
" a time would come when the princes and nobles of
" neighbouring lands would be as eager to obtain horses
" from England as ever the English had been to obtain
" horses from Barbary."

The London dray-horse, which differs so much in ap-
pearance from any natural species, and which from its
size has so astonished many Eastern princes, was prob-
ably formed by the heaviest and most powerful animals
having been selected during many generations in Flanders
and England, but without the least intention or expecta-
tion of creating a horse such as we now see. If we go
back to an early period of history, we behold in the an-
tique Greek statues, as Schaaffhausen has remarked,75 a
horse equally unlike a race or dray horse, and differing
from any existing breed.

The results of unconscious selection, in an early stage,
are well shown in the difference between the flocks de-
scended from the same stock, but separately reared by
careful breeders. Youatt gives an excellent instance
of this fact in the sheep belonging to Messrs. Buckley
and Burgess, which " have been purely bred from the ori-
" giual stock of Mr. Bakewell for upwards of fifty years.
" There is not a suspicion existing in the mind of any one
" at all acquainted with the subject that the owner of
" either flock has deviated in any one instance from the
"pure blood of Mr. Bakewell's flock; yet the difference
" between the sheep possessed by these two gentlemen is

74 ' History of England,' vol. i. p. 316. 7S ' Ueber Bestandigkeit der Arten.

Chap. XX. UNCONSCIOUS SELECTION. 259

"so great, that they have the appeai-ance of being quite
" different varieties." 76 I have seen several analogous and
well-marked cases with pigeons : for instance, I had a fam-
ily of barbs, descended from those long bred by Sir J. Se-
bright, and another family long bred by another fancier,
and the two families plainly differed from each other.
Nathusius — and a more competent witness could not be
cited — observes that, though the Shorthorns are remark-
ably uniform in appearance (except in colouring), yet that
the individual character and wishes of each breeder be-
come impressed on his cattle, so that different herds differ
slightly from each other." The Hereford cattle assumed
their jjresent well-marked character soon after the year
1769, through careful selection by Mr. Tomkins,78 and
the breed has lately split into two strains — one strain
having a white face, and differing slightly, it is said,79 in
some other poiuts ; but there is no reason to believe that
this split, the origin of which is unknown, was intentionally
made ; it may with much more probability be attributed
to different breeders having attended to different points.
So again, the Berkshire breed of swine in the year 1810
had greatly changed from what it had been in 1780 ; and
since 1810 at least two distinct sub-breeds have borne this
same name.80 When we bear in mind how rapidly all ani-
mals increase, and that some must be annually slaughtered
and some saved for breeding, then, if the same breeder
during a long course of years deliberately settles which
shall be saved and which shall be killed, it is almost in-
evitable that his individual frame of mind will influence
the chai-acter of his stock, without his having had any
intention to modify the breed or form a new strain.

Unconscious selection in the strictest sense of the word,
that is, the saving of the more useful animals and the

78 Youatt on Sheep, p. 315. p. 3G3.

77 ' Ueber Shorthorn Rindvieh,' 1S57, 79 ' Quarterly Review,' 1849, p. 892.

s. 51. 80 II. von Nathusius, ' Vorstudien

78 Low, ' Domesticated Animals,' 1S45, . . . . Schweineschaedel,' 1S64, s. 140.

260 SELECTION". Chap. XX

neglect or slaughter of the less useful, without any thought
of the future, must have gone on occasionally from the
remotest period and amongst the most barbarous nations.
Savasres often suffer from famines, and are sometimes ex-
pelled by war from their own homes. In such cases it
can hardly be doubted that they would save their most
useful animals. When the Fuegians are hard pressed by
want, they kill their old women for food rather than their
dogs ; for, as we were assured, " old women no use — dogs
catch otters." The same sound sense would surely lead
them to preserve their more useful dogs when still harder
pressed by famine. Mr. Oldfield, who has seen so much
of the aborigines of Australia, informs me that "they are
all very glad to get a European kangaroo dog, and several
instances have been known of the father killing his own
infant that the mother might suckle the much-prized
puppy." Different kinds of dogs would be useful to the
Australian for hunting opossums and kangaroos, and to
the Fuegian for catching fish and otters; and the oc-
casional preservation in the two countries of the most
useful animals would irltimately lead to the formation of
two widely distinct breeds.

"With plants, frdm the earliest dawn of civilization, the
best variety which at each period was known would gen-
erally have been cultivated and its seeds occasionally
sown ; so that there will have been some selection from
an extremely remote period, but without any prefixed
standard of excellence or thought of the future. We at
the present day profit by a course of selection occasion-
ally and unconsciously cai-ried on during thousands of
years. This is proved in an interesting manner by Os-
wald Heer's researches on the lake-inhabitants of Swit-
zerland, as given in a former chapter; for he shows that
the grain and seed of our present varieties of wheat, bar-
ley/ oats, peas, beans, lentils, and poppy, exceed in size
those which were cultivated in Switzerland during the

Chap. XX. UNCONSCIOUS SELECTION. 261

Neolithic and Bronze periods. These ancient people,
during the Neolithic period, possessed also a crab con-
siderably larger than that now growing wild on the
Jura.81 The pears described by Pliny were evidently
extremely inferior in quality to our present pears. We
can realize the effects of long-continued selection and cul-
tivation in another way, for would any one in his senses
expect to raise a first-rate apple from the seed of a truly
wild crab, or a luscious melting pear from the wild pear ?
Alphonse De Candolle informs me that he has lately seen
on an ancient mosaic at Rome a representation of the
melon ; and as the Romans, who were such gourmands,
are silent on this fruit, he infers that the melon has been
greatly ameliorated since the classical period.

Coming to later times, Buffbn,82 on comparing the
flowers, fruit, and vegetables which were then cultivated,
with some excellent drawings made a hundred and fifty
years previously, was struck with surprise at the great
improvement which had been effected ; and remarks that
these ancient flowers and vegetables would now be re-
jected, not only by a florist but by a village gardener.
Since the time of Buffbn the work of improvement has
steadily and rapidly gone on. Every florist who com-
pares our present flowers with those figured in books
published not long since, is astonished at the change. A
well-known amateur,83 in speaking of the varieties of Pe-
largonium raised by Mr. Garth only twenty-two years
before, remarks, " what a rage they excited : surely Ave
" had attained perfection, it was said ; and now not one
" of the flowers of those days will be looked at. But none
"the less is the debt of gratitude which we owe to those
" who saw what was to be done, and did it." Mr. Paul,
the well-known horticulturist, in writing of the same

81 See also Dr. Christ, in ' Uutimeyer's d'Accliraat.,' 1S5S, p. 11.
Pfahlbauten,' 1861, s. 226. es ' Journal of Horticulture,' 1862, p.

83 The passage is given ' Bull. Soc. 804?

262 SELECTION. Chap. XX.

flower,84 says he remembers when young being delighted
with the portraits in Sweet's work ; " but what are
" they in point of beauty compared with the Pelargoniums
" of this day ? Here again nature did not advance by
"leaps; the improvement was gradual, and, if we had
" neglected those very gradual advances, we must have
"foregone the present grand results." How well this
practical horticulturist appreciates and illustrates the
gradual and accumulative force of selection ! The Dahlia
has advanced in beauty in a like manner ; the line of im-
provement being guided by fashion, and by the succes-
sive modifications which the flower slowly underwent.85
A steady and gradual change has been noticed in many
other flowers : thus an old florist,86 after describing the
leading varieties of the Pink which were grown in 1813,
adds, " the pinks of those days would now be scarcely
"grown as border-flowers." The improvement of so
many flowers and the number of the varieties which have
been raised is all the more striking when we hear that
the earliest known flower-garden in Europe, namely, at
Padua, dates only from the year 1545. e7

Effects of Selection, as shoicn by the parts most valued
by man presenting the greatest amount of Difference. —
The power of long-continued selection, whether methodi-
cal or unconscious, or both combined, is well shown in a
general way, namely, by the compai*ison of the differen-
ces between the varieties of distinct species, which are
valued for different parts, such as for the leaves, or stems,
or tubers, the seed, or fruit, or flowers. Whatever part
man values most, that part will be found to present the
greatest amount of difference. With trees cultivated for
their fruit, Sageret remarks that the fruit is larger than

84 'Gardener's Chronicle,' 1S57, p. 85. 86 'Journal of Horticulture,' Oct. 24th,

85 See Mr. Wildman's address to the 1865, p. 239.

Floricult. Soc, in ' Gardener's Chroni- 87 Prescott's ' Hist, of Mexico,' vol. il.

cle,' 1843, p. 86. p. 61.

Chap. XX. SELECTION. 263

in the parent-species, whilst with those cultivated for the
seed, as with nuts, walnuts, almonds, chesnuts, &c, it is
the seed itself which is larger ; and he accounts for this
fact by the fruit in the one case, and by the seed in the
other, having been carefully attended to and selected
during many ages. Gallesio has made the same observa-
tion. Godron insists on the diversity of the tuber in the
potato, of the bulb in the onion, and of the fruit in the
melon; and 'on the close similarity in these same plants
of the other parts. 88

In order to judge how far my own impression on this
subject was correct, I cultivated numerous varieties of
the same species close to each other. The comparison of
the amount of difference between widely different organs
is necessarily vagtie ; I will therefore give the results in
only a few cases. "We have previously seen in the ninth
chapter how greatly the varieties of the cabbage dif-
fer in their foliage and stems, which are the selected
parts, and how closely they resemble each other in their
flowers, capsules, and seeds. In seven varieties of the
radish, the roots differed greatly in colour and shape, but
no difference whatever could be detected in their foliage,
flowers, or seeds. Now what a contrast is presented, if
we compare the flowers of the varieties of these two
plants with those of any species cultivated in our flower-
gardens for ornament; or if we compare their seeds with
those of the varieties of maize, peas, beans, &c, which I
are valued and cultivated for their seeds. In the ninth
chapter it was shown that the varieties of the pea differ
but little except in the tallness of the plant, moderately
in the shape of the pod, and greatly in the pea itself, and
these are all selected points. The varieties, however, of

88 Sageret, ' Pomologie Physiologique,' have given details on the potato; and I
1&30, p. 47; Gallesio, 'Teoria della Ri- can confirm similar remarks with respect
produzione,' 1S16, p. SS ; Godron, ' De to the onion. I have also shown how
l'Espece,' 1S59, torn. ii. pp. 63, 67, 70. far Naudin concurs in regard to the va-
in my tenth and eleventh chapters I' rleties of the melon.

264 SELECTION. Chap. XX.

the JPois sans parck&nin differ much more in their pods,
and these are eaten and valued. I cultivated twelve
varieties of the common bean; one alone, the Dwarf
Fan, differed considerably in general appearance ; two
differed in the colour of their flowers, one being an albino,
and the other being wholly instead of partially purple ;
several differed considerably in the shape and size of the
pod, but far more in the bean itself, and this is the valued
and selected part. Toker's bean, for instance, is twice-
and-a-half as long and broad as the horse-bean, and is
much thinner and of a different shape.

The varieties of the gooseberry, as formerly described,
differ much in their fruit, but hardly perceptibly in their
flowers or organs of vegetation. With the plum, the
differences likewise appear to be greater in the fruit than
in the flowers or leaves. On the other hand, the seed of
the strawberry, which corresponds with the fruit of the
plum, differs hardly at all ; whilst every one knows how
greatly the fruit — that is, the enlarged receptacle — differs
in the several varieties. In apples, pears, and peaches
the flowers and leaves differ considerably, but not, as far
as I can judge, in proportion with the fruit. The Chinese
double-flowering peaches, on the other hand, show that
varieties of this tree have been formed, which differ more
in the flower than in the fruit. If, as is highly probable, the
peach is the modified descendant of the almond, a sur-
prising amount of change has been effected in the same
species, in the fleshy covering of the former and in the
kernels of the latter.

When parts stand in such close relation to each other
as the fleshy covering of the fruit (whatever its homologi-
cal nature may be) and the seed, when one pai*t is modi-
fied, so generally is the other, but by no means necessa-
rily in the same degree. With the plum-tree, for instance,
some varieties produce plums which are nearly alike, but
include stones extremely dissimilar in shape ; whilst con-
versely other varieties produce dissimilar fruit with barely

Chap. XX. SELECTION. 265

distinguishable stones; and generally the stones, though
they have never been subjected to selection, differ greatly
in the several varieties of the plum. In other cases or-
gans which are not manifestly related, through some un-
known bond vary together, and are consequently liable,
without any intention on man's part, to be simultaneously
acted on by selection. Thus the varieties of the stock
(Matthiola) have been selected solely for the beauty of
their flowers, but the seeds differ greatly in colour and
somewhat in size. Varieties of the lettuce have been
selected solely on account of their leaves, yet produce
seeds which likewise differ in colour. Generally, through
the law of correlation, when a variety differs greatly from
its fellow-varieties in any one character, it differs to a
certain extent in several other characters. I observed
this fact when I cultivated together many varieties of
the same species, for I used first to make a list of the
varieties which differed most from each other in their
foliage and manner of growth, afterwards of those that
differed most in their flowers, then in their seed-capsules,
and lastly in their mature seed ; and I found that the
same names generally occurred in two, three, or four of
the successive lists. Nevertheless the greatest amount
of difference between the varieties was always exhibited,
as far as I could judge, by that part or organ for which
the plant was cultivated.

When we bear in mind that each plant was at first
cultivated because useful to man, and that its variation
was a subsequent, often a long subsequent, event, we
cannot explain the greater amount of diversity in the
valuable parts by supposing that species endowed with
an especial tendency to vary in any particular manner,
were originally chosen. We must attribute the result to
the variations in these parts having been successively pre-
served, and thus continually augmented; whilst other
variations, excepting such as inevitably appeared through
correlation, were neglected and lost. Hence we may

26G SELECTION. Chap. XX.

infer that most plants might be made, through long-con-
tinued selection, to yield races as different from each
other in any character as they now are in those parts for
which they are valued and cultivated.

With animals we see something of the same kind ; but
"they have not been domesticated in sufficient number or
yielded sufficient varieties for a fair comparison. Sheep
are valued for their wool, and the wool differs much more
in the several races than the hair in cattle. Neither
sheep, goats, European cattle, nor pigs are valued for
their fleetness or strength ; and we do not possess breeds
differing in these respects like the race-horse and dray-
horse. But fleetness and strength are valued in camels
and dogs,; and we have with the former the swift dro-
medary and heavy camel; with the latter the greyhound
and mastiff. But dogs are valued even in a higher degree
for their mental qualities and senses; and every one
knows how greatly the races differ in these respects. On
the other hand, where the dog is valued solely to serve
for food, as in the Polynesian islands and China, it is de-
scribed as an extremely stupid animal.89 Blumenbach
remarks that " many dogs, such as the badger-dog, have
" a build so marked and so appropriate for particular pur-
" poses, that I should find it very difficult to persuade
" myself that this astonishing figure was an accidental
" consequence of degeneration." 90 But had Blumenbach
reflected on the great principle of selection, he would not
have used the term degeneration, and he would not have
been astonished that dogs and other animals should be-
come excellently adapted for the service of man.

On the whole we may conclude that whatever part or
character is most valued — .whether the. leaves, stems,
tubers, bulbs, flowers, fruit, or seed of plants, or the size,
strength, fleetness, hairy covering, or intellect of animals

88 Godron, ' De l'Espece,' torn. ii. p. 00 ' The Anthropological Treatises of

27. Blumenbaob,' 1S65, p. 292.

Ciup. XX. SELECTION". 267

— that character will almost invariably be found to pre-
sent the greatest amount of difference both in kind and
degree. And this result may be safely attributed to m;m
having preserved during a long course of generations the
variations which were useful to him, and neglected the
others.

• I will conclude this chapter by some remarks on an
important subject. With animals such as the giraffe, of
which the whole structure is admirably co-ordinated for
certain purposes, it has been supposed that all the parts
must have been simultaneously modified ; and it has been
argued that, on the principle of natural selection, this
is scarcely possible. But in thus arguing, it has been
tacitly assumed that the variations must have been abrupt
and great. Xo doubt, if the neck of a ruminant were
suddenly to become greatly elongated, the fore limbs and
back would have to be simultaneously strengthened and
modified; but it cannot be denied that an animal might
have its neck, or head, or tongue, or fore-limbs elongated
a very little without any corresponding modification in
other parts of the body ; and animals thus slightly modi-
fied would, during a dearth, have a slight advantage,
and be enabled to browse on higher twigs, and thus sur-
vive. A few mouthfuls more or less every day would
make all the difference between life and death. By the
repetition of the same process, and by the occasional
intercrossing of the survivors, there would be some pro-
gress, slow and fluctuating though it would be, towards
the admirably co-ordinated structure of the giraffe. If
the short-faced tumbler-pigeon, with its small conical beak,
globular head, rounded body, short wings, and small
feet — characters which appear all in harmony — had been
a natural species, its whole structure Avould have been
viewed as well fitted for its life; but in this case we know
that inexperienced breeders are urged to attend to point
after point, and not to attempt improving the whole

268 SELECTION. Chap. XX.

structure at the same time. Look at the greyhound,
that perfect image of grace, symmetry, and vigour ; no
natural species can boast of a more admirably co-ordinat-
ed structure, with its tapering head, slim body, deep
chest, tucked-up abdomen, rat-like tail, and long muscular
limbs, all adapted for extreme fleetness, and for running
down weak prey. Now, from what we see of the varia-
bility of animals, and from what we know of the method
which different men follow in improving their stock —
some chiefly attending to one point, others to another
point, others again correcting defects by crosses, and so
forth — we may feel assured that if we could see the long
line of ancestors of a first-rate greyhound, up to its wild-
wolf-like progenitor, we should behold an infinite number
of the finest gradations, sometimes in one character and
sometimes in another, but all leading towards our present
perfect type. By small and doubtful steps such as these,
nature, as we may confidently believe, has progressed on
her grand march of improvement and development.

A similar line of reasoning is as applicable to separate
organs as to the whole organisation. A writer91 has re-
cently maintained that " it is probably no exaggeration
" to suppose that, in order to improve such an organ as
"the eye at all, it must be improved in ten different
" ways at once. And the improbability of any com-
" plex organ being produced and brought to perfection
" in any such way is an improbability of the same kind
" and degree as that of producing a poem or a mathe-
" matical demonstration by throwing letters at random
" on a table." If the eye were abruptly and greatly
modified, no doubt many parts would have to be simul-
taneously altered, in order that the organ should remain
serviceable.

91 Mr. J. J. Murphy in his opening previously and more cautiously given

address to the Belfast Nat. Hist. Soc, by the Rev. C. Pritchard, Pres. Royal

as given in the Belfast Northern Whig, Astronomical Soc, in his sermon (Ap-

Nov. 19, 1SCG. Mr. Murphy here follows pendix, p. 33) preached before the Brit-

the line of argument against my views ish Association at Nottingham, 1S66.

Chap. XX. SELECTION. 269

But is this the case with smaller changes ? There are
persons who can see distinctly only in a dull light, and
this condition depends, I believe, on the abnormal sensi-
tiveness of the retina, and is known to be inherited.
Now, if a bird, for instance, received some great ad-
vantage from seeing well in the twilight, all the indi-
viduals with the most sensitive retina would succeed
best and be the most likety to survive; and why should
not all those which happened to have the eye itself a
little larger, or the pupil capable of greater dilatation,
be likewise preserved, whether or not these modifica-
tions were strictly simultaneous ?» These individuals
would subsequently intercross and blend their respec-
tive advantages. By such slight successive changes,
the eye of a diurnal bird •would be brought into the
condition of that of an owl, which has often been ad-
vanced as an excellent instance of adaptation. Short-
sight, which is often inherited, permits a person to see
distinctly a minute object at so near a distance that it
would be indistinct to ordinary eyes ; and here we have
a capacity which might be serviceable under certain con-
ditions, abruptly gained. The Fuegians on board the
Beagle could certainly see distant objects more dis-
tinctly than our sailors with all their long practice ; I
do not know whether this depends on nervous sensitive-
ness or on the power of adjustment in the focus ; but
this capacity for distant vision might, it is probable, be
slightly augmented by successive modifications of either
kind. Amphibious animals, which ai-e enabled to see
both in the water and in the air, require and possess, as
M. Plateau has shown,92 eyes constructed on the follow-
ing plan : " the cornea is always flat, or at least much
"flattened in front of the crystalline and over a space
"equal to the diameter of that lens, whilst the lateral

•* On the Vision of Fishes and Amphibia, translated in ' Annals and Mag. of Nat.
Hist.,' vol. xviii., 1866, p. 469.

2 70 SELECTION". C^p. XX.

"portions .may be much curved." The crystalline is
very nearly a sphere, and the humours have nearly the
same density as water. Now, as a terrestrial animal
slowly became more and more aquatic in its habits,
very slight changes, first in the curvature of the cor-
nea or crystalline, and then in the density of the hu-
mours, or conversely, might successively occur, and would
be advantageous to the animal whilst under water, with-
out serious detriment to its power of vision in the air.
It is of course impossible to conjecture by what steps
the fundamental structure of the eye in the Vertebrata
was originally acquired, for we know absolutely nothing
about this organ in the first progenitors of the class.
With respect to the lowest animals in the scale, the
transitional states through which the eye at first pro-
bably passed, can by the aid of analogy be indicated,
as I have attempted to show in my ' Origin of Species.'"

98 Fourth edition, 1866, p. 215.

Chap. XXI. SELECTION. 271

CHAPTER XXI.

SELECTION, continued.

NATURAL SELECTION AS AFFECTING DOMESTIC PRODUCTIONS —
CHARACTERS WHICH APPEAR OF TRIFLING VALUE OFTEN OF
REAL IMPORTANCE — CIRCUMSTANCES FAVOURABLE TO SELEC-
TION BY MAN — FACILITY IN PREVENTING CROSSES, AND THE
NATURE OF TnE CONDITIONS — CLOSE ATTENTION AND PERSE-
VERANCE INDISPENSABLE — THE PRODUCTION OF A LARGE
NUMBER OF INDIVIDUALS ESPECIALLY FAVOURABLE — WHEN
NO SELECTION IS APPLIED, DISTINCT RACES ARE NOT FORMED
— HIGHLY-BRED ANIMALS LIABLE TO DEGENERATION — TEN-
DENCY IN MAN TO CARRY THE SELECTION OF EACH CHARAC-
TER TO AN EXTREME POINT, LEADING TO DIVERGENCE OF
CHARACTER, RARELY TO CONVERGENCE — CHARACTERS CON-
TINUING TO VARY IN THE SAME DIRECTION IN WHICH THEY
HAVE ALREADY VARIED — DIVERGENCE OF CHARACTER. WITH
THE EXTINCTION OF INTERMEDIATE VARIETIES, LEADS TO DIS-
TINCTNESS IN OUR DOMESTIC RACES — LIMIT TO THE POWER
OF SELECTION — LAPSE OF TIME IMPORTANT — MANNER IN
WniCU DOMESTIC RACES HAVE ORIGINATED — SUMMARY.

Natural Selection, or the Survival of the Fittest, as af-
fecting domestic productions. — We know little on this
head. But as animals kept by savages have to provide
their own food, either entirely or to a large extent,
throughout the year, it can hardly be doubted that, in
different countries, varieties differing in constitution and
in various characters would succeed best, and so be na-
turally selected. Hence perhaps it is that the few do-
mesticated animals kept by savages partake, as has been
remarked by more than one writer, of the wild appear-
ance of their masters, and likewise resemble natural spe-

272 SELECTION. Chap. XXI.

cies. Even in long-civilised countries, at least in the
wilder parts, natural selection must act on our domes-
tic races. It is obvious that varieties, having very dif-
ferent habits, constitution, and structure, would succeed
best on mountains and on rich lowland pastures. For
example, the improved Leicester sheep were formerly
taken to the Lammermuir Hills; but an intelligent sheep-
master reported that " our coarse lean pastures were un-
" equal to the task of supporting such heavy-bodied sheep ;
" and they gradually dwindled away into less andless bulk:
" each generation was inferior to the preceding one ; and
" when the spring was severe, seldom more than tAvo-thirds
" of the lambs survived the ravages of the storms." ' So
with the mountain cattle of North Wales and the He-
brides, it has been found that they could not withstand
being crossed with the larger and more delicate lowland
breeds. Two French naturalists, in describing the horses
of Circassia, remark that, subjected as they are to extreme
vicissitudes of climate, having to search for scanty pasture,
and exposed to constant danger from wolves, the strong-
est and most vigorous alone survive.2

Every one must have been struck with the surpassing
grace, strength, and vigour of the Game-cock, with its
bold and confident air, its long, yet firm neck, compact
body, powerful and closely pressed wings, muscular
thighs, strong beak massive at the base, dense and sharp
sjmrs set low on the legs for delivering the fatal blow,
and its compact, glossy, and mail-like plumage serving
as a defence. Now the English game-cock has not only
been improved during many years by man's careful selec-
tion, but in addition, as Mr. Tegetmeier has remarked,3 by
a kind of natural selection, for the strongest, most active
and courageous birds have stricken down their antago-

1 Quoted by Youatt on Sheep, p. 325. in 'Bull. Soc. Acclimat.,' torn, viii., 1S61,
See also Youatt on Cattle, pp. 62, 69. p. Sll.

3 MM. Lherbette and De Quatrefages, s 'The Poultry Book,' 1SC6, p. 123.

Chap. XXI. NATURAL SELECTION. 273

nists in the cock-pit, generation after generation, and have
subsequently served as the progenitors of their kind.

In Great Britain, in former times, almost every district
had its own breed of cattle and sheep; " they were indi-
" genous to the soil, climate, and pasturage of the locality
" on which they grazed : they seemed to have been formed
" for it and by it." 4 But in this case we are quite unable
to disentangle the effects of the direct action of the con-
ditions of life — of use or habit — of natural selection — and
of that kind of selection which we have seen is occasion-
ally and unconsciously followed by man even during the
rudest periods of history.

Let us now look to the action of natural selection on
special characters. Although nature is difficult to resist,
yet man often strives against her power, and sometimes,
as we shall see, with success. From the facts to be given,
it will also be seen that natural selection would power-
fully affect many of our domestic productions if left un-
protected. This is a point of much interest, for Ave thus
learn that differences apparently of very slight importance
would certainly determine the survival of a form when
forced to struggle for its own existence. It may have
occurred to some naturalists, as it formerly did to me,
that, though selection acting under natural conditions
would determine the structure of all important organs,
yet that it could not affect characters which are esteemed
by us of little importance ; but this is an error to which
we are eminently liable, from our ignorance of what
characters are of real value to each living creature.

When man attempts to breed an animal with some
serious defect in structure, or in the mutual relation of
parts, he will either partially or completely fail, or en-
counter much difficulty; and this is in fact a form of
natural selection. "We have seen that the attempt was
once made in Yorkshire to breed cattle with enormous

♦ Youatt on Sheep, p. 812.

274 SELECTION. Chap. XXI.

buttocks, but the cows perished so often in bringing,
forth their calves, that the attempt had to be given up.
In rearing short-faced tumblers, Mr. Eaton says,5 '' I am
" convinced that better head and beak birds have per-
" ished in the shell than ever were hatched ; the reason
" being that the amazingly short-faced bird cannot reach
"and break the shell with its beak, and so perishes."
Here is a more curious case, in which natural selection
comes into play only at long intervals of time : during
ordinary seasons the Niata cattle can graze as well as
others, but occasionally, as from 1827 to 1830, the plains
of La Plata suffer from long-continued droughts and the
pasture is burnt up ; at such times common cattle and
horses perish by the thousand, but many survive by
browsing on twigs, reeds, <fcc. ; this the Niata cattle
cannot so well effect from their upturned jaws and the
shape of their lips ; consequently, if not attended to, they
perish before the other cattle. In Colombia, according to
Roulin, there is a breed of nearly hairless cattle, called
Pelones; these succeed in their native hot district, but
are found too tender for the Cordillera; in this case,
natural selection determines only the range of the variety.
It is obvious that a host of* artificial races could never
survive in a state of nature ; — such as Italian greyhounds,
— hairless and almost toothless Turkish dogs, — fantail
pigeons, which cannot fly well against a strong wind, —
barbs with their vision impeded by their eye-wattle, —
Polish fowls with their vision impeded by their great
topknots, — hornless bulls and rams which consequently
cannot cope with other males, and thus have a poor
chance of leaving offspring, — seedless plants, and many
other such cases.

Colour is generally esteemed by the systematic nat-
uralist as unimportant : let us, therefore, see how far it
indirectly affects our domestic productions, and how far

8 'Treatise on the Almond Tumbler,' 1S51, p. 33.

Chap. XXL NATURAL SELECTION. 275

it would affect them if* they were left exposed to the full
force of natural selection. In a future chapter I shall
have to show that constitutional peculiarities of the
strangest kind, entailing liability to the action of certain
poisons, are correlated with the colour of the skin. I
will here give a single case, on the high authority of
Professor Wyman ; he informs me that, being surprised
at all the pigs in a part of Virginia* being black, he
made inquiries, and ascertained that these animals feed
on the roots of the Lachnanthes tinctoria, which col-
ours their bones pink, and, excepting in the case of the
black varieties, causes the hoofs to drop off. Hence,
as one of the squatters remarked, " we select the black
members of the litter for raising, as they alone have a
good chance of living." So that here we have artificial
and natural selection working hand in hand. I may add
that in the Tarentino the inhabitants keep black sheep
alone, because the Hypericum crispum abounds there ;
and this plant does not injure black sheep, but kills the
white ones in about a fortnight's time.6

Complexion, and liability to certain diseases, are be-
lieved to run together in man and the lower animals.
Thus white terriers suffer more than terriers of any other
colour from the fatal Distemper.7 In North America
plum-trees are liable to a disease which Downing8 be-
lieves is not caused by insects ; the kinds bearing purple
fruit are most affected, " and we have never known the
" green or yellow fruited varieties infected until the
" other sorts had first become filled with the knots."
On the other hand, peaches in North America suffer
much from a disease called the yellows, which seems to
be peculiar to that continent, and "more than nine-
" tenths of the victims, when the disease first appeared,
" were the yellow-fleshed peaches. The white-fleshed

* Should be Florida.— Pen. T Youatt on th* Do?, p. 232.

* Dr. Heusinger, ' Wnchenschrift fur * 'The Fruit-trees of America,' 1S43,
die Ueilkunde,' Berlin, 1846, s. 279. p. 2T0: for pcaclies, p. 400.

276 SELECTION". Chap. XXI.

" kinds are much more rarely attacked ; in some parts
" of the country never." In Mauritius, the white sugar-
canes have of late years been so severely attacked by
a disease, that many planters have been compelled to
give up growing this variety (although fresh plants
were imported from China for trial), and cultivate only
red canes.9 Now, if these plants had been forced to
struggle with other competing plants and enemies, there
cannot be a doubt that the colour of the flesh or skin of
the fruit, unimportant as these characters are considered,
would have rigorously determined their existence.

Liability to the attacks of parasites is also connected
with colour. It appears that white chickens are certain-
ly more subject than dark-coloured chickens to the gapes,
which is caused by a parasitic worm in the trachea.10
On the other hand, experience has shown that ia France
the caterpillars which produce white cocoons resist
the deadly fungus better than those producing yellow
cocoons." Analogous facts have been observed with
plants : a new and beautiful white onion, imported from
France, though planted close to other kinds, was alone
attacked by a parasitic fungus.12 White verbenas are
especially liable to mildew.13 Near Malaga, during an
early period of the vine-disease, the green sorts suffered
most; "and red and black grapes, even when inter-
woven with the sick plants, suffered not at all." In
France whole groups of varieties were comparatively
free, and others, such as the Chasselas, did not afford a
single fortunate exception ; but I do not know whether
any correlation between colour and liability to disease
was here observed.14 In a former chapter it was shown
how curiously liable one variety of the strawberry is to
mildew.

9 ' Proc. Royal Soc. of Arts and Sci- 13 'Gardener's Chronicle,' 1851, p. 595.
ences of Mauritius,' 1S52, p. cxxxv. 13 'Journal of Horticulture,' 1862, p.

10 ' Gardener's ChronTcle,' 1S56, p. 379. 47G.

11 Quatrefages, ' Maladies Actuelles du 14 ' Gardener's Chronicle,' 1S52, pp.
Ver a 3oie,' 1859, pp. 12, 214. 435, 691.

Chap. XXI. NATURAL SELECTION. 277

It is certain that insects regulate in many cases the
range and even the existence of the higher animals,
whilst living under their natural conditions. Under do-
mestication light-coloured animals suffer most : in Thu-
ringia 1S the inhabitants do not like grey, white, or pale
cattle, because they are much more troubled by various
kinds of flies than the brown, red, or black cattle. An
Albino negro, it has been remarked,16 was peculiarly sen-
sitive to the bites of insects. In the West Indies ,7 it is
said that " the only horned cattle fit for work are those
" which have a good deal of black in them. The white
" are terribly tormented by the insects ; and they are weak
" and sluggish in proportion to the white."

In Devonshire there is a prejudice against white pigs,
because it is believed that the sun blisters them when
turned out ; 18 and I knew a man who would not keep
white pigs in Kent, for the same reason. The scorching
of flowers by the sun seems likewise to depend much on
colour; thus, dark pelargoniums suffer most; and from
various accounts it is clear that the cloth-of-gold vari-
ety will not withstand a degree of exposure to sunshine
which other varieties enjoy. Another amateur asserts
that not only all dark-coloured verbenas, but likewise
scarlets, suffer from the sun ; " the paler kinds stand bet-
ter, and pale blue is perhaps the best of all." So again
with the heartsease ( Viola tricolor) ; hot weather suits
the blotched sorts, whilst it destroys the beautiful mark-
ings of some other kinds.19 During one extremely cold
season in Holland all red-flowered hyacinths were ob-
served to be very inferior in quality. It is believed by

15 Bechstein, ' Naturgesch. Deutsch- 18 Sidney's edit, of Youatt on the Pig,

lands,' 1 SOI. B. i. s. 310. p. 24.

14 Prichard, ' Phys. Hist, of Mankind,' ,9 ' Journal of Horticulture,' 1S62, pp.

1S51, vol. i. p. 224. 476, 499 ; 1S65, p. 460. With respect to

17 G. Lewis's ' Journal of Residence the heartsease. ' Gardener's Chronicle,'

In West Indies,' ' Home and Col. Li- 1SC3, p. 623.
brary,' p. 100.

278 SELECTION. Chap. XXI.

many agriculturists that red wheat is hardier in northern
climates than white wheat.20

With animals, white varieties from being conspicuous
are the most liable to be attacked by beasts and birds of
prey. In parts of France and Germany where hawks
abound, persons are advised not to keep white pigeons ;
for, as Parmentier says, " it is certain that in a flock the
white always first fall victims to the kite." In Belgium,
where so many societies have been established for the
flight of carrier-pigeons, white is the one colour which
for the same reason is disliked.21 On the other hand, it
is said that the sea-eagle (ttdco ossifragus, Linn.) on the
west coast of Ireland picks out the black fowls, so that
" the villagers avoid as much as possible rearing birds of
that colour." M. Daudin,22 speaking of white rabbits
kept in warrens in Russia, remarks that their colour is a
great disadvantage, as they are' thus more exposed to at-
tack, and can be seen during bright nights from a dis-
tance. A gentleman in Kent, who failed to stock his
woods with a nearly white and hardy kind of rabbit, ac-
counted in the sam^ manner for their early disappearance.
Any one who will watch a white cat prowling after her
prey will soon perceive under what a disadvantage she
lies.

The white Tartarian cherry, "owing either to its co-
lour being so much like that of the leaves, or to the fruit
always appearing from a distance unripe," is not so read-
ily attacked by birds as other sorts. The yellow-fruited
raspberry, which generally comes nearly true by seed, "■ is
very little molested by birds, who evidently are not fond
of it; so that nets may be dispensed with in places where
nothing else will protect the red fruit." 23 This immunity,

20 'Des Jacinthes, de leur Culture,' see a quotation in Thompson's 'Nat.

1768, p. 53: on wheat, 'Gardener's Hist, of Ireland,' 1849, vol. i. p. 22.

Chronicle,' 1846, p. 653. 2'2 'Bull, de la Soc. d'Acclimat.,' torn.

a> W. B. Tegetmeier, ' The Field,' Feb. vii. 1860, p. 359.

25, 1S65. With respect to black fowls, 23 'Transact. Hort. Soc.,' rol. i. 2nd

Chap. XXI. NATURAL SELECTION. 279

though a .benefit to the gardener, would be a disadvan-
tage in a state of nature both to the cherry and raspberry,
as their dissemination depends on birds. I noticed dur-
ing several winters that some trees of the yellow-berried
holly, which were raised from seed from a wild tree found
by my father, remained covered with fruit, whilst not a
scarlet berry could be seen on the adjoining trees of the
common kind. A friend informs me that a mountain-ash
(Pi/rus auciqxiria) growing in his garden bears berries
which, though not diiferently coloured, are always de-
voured by birds before those on the other trees. This
variety of the mountain-ash would thus be more freely
disseminated, and the yellow-berried variety of the holly
less freely, than the common varieties of these two trees.

Independently of colour, other trifling differences are
sometimes found to be of importance to plants under
cultivation, and would be of paramount importance if
they had to fight their own battle and to struggle with
many competitors. The thin-shelled peas, called 2)ois
sans parchemin, are attacked by birds M much more than
common peas. On the other hand, the purple-podded
pea, which has a hard shell, escaped the attacks of tomtits
(Pcmis major) in my garden far better than any other
kind. The thin-shelled walnut likewise suffers greatly
from the tomtit.25 These same birds have been observed
to pass over and thus favour the filbert, destroying only
the other kinds of nuts which grew in the same orchard.26

Certain varieties of the pear have soft bark, and these
suffer severely from boring wood-beetles ; whilst other
varieties are known to resist their attacks much better.37
In North America the smoothness, or absence of down on
the fruit, makes a great difference in the attacks of the
weevil, " which is the uncompromising foe of all smooth

series, 1885, p. 275. For raspberries, 25 Ibid., 1S50, p. 73'2.

see ' Gard. Chronicle,' 1S55, p. 154, and 2« Ib:d., 1SG0, p. 956.

1SC8, p. 245. 27 j. De Jonghe, in ' Gard. Chronicle,'

2« ' Gardener's Chronicle,' 1S43, p. S06. 1S60, p. 120.

280 SELECTION. Chap. XXI.

stone-fruits ;" and the cultivator " has the frequent morti-
fication of seeing nearly all, or indeed often the whole
crop, fall from the trees when half or two-thirds grown."
Hence the nectarine suffers more than the peach. A par-
ticular variety of the Morello cherry, raised in North
America, is without any assignable cause more liable to
be injured by this same insect than other cherry-trees.28
From some unknown cause, the Winter Majetin apple
enjoys the great advantage of not being infested by the
coccus. On the other hand, a particular case has been
recorded in which aphides confined themselves to the
Winter Nelis pear, and touched no other kind in an ex-
tensive orchard."9 The existence of minute glands on the
leaves of peaches, nectarines, and apricots, would not be
esteemed by botanists as a character of the least impor-
tance, for they are present or absent in closely related sub-
varieties, descended from the same parent-tree ; yet there
is good evidence 30 that the absence of glands leads to
mildew, which is highly injurious to these trees.

A difference either in flavour or in the amount of nu-
triment in certain varieties causes them to be more eager-
ly attacked by various enemies than other varieties of the
same species. Bullfinches {Pyrrhula vulgaris) injure our
fruit-trees by devouring the flower-buds, and a pair of
these birds have been seen "to denude a large plum-tree
in a couple of days of almost every bud ;" but certain
varieties 31 of the apple and thorn (Crataegus oxyacantha)
are more especially liable to be attacked. A striking
instance of this was observed in Mr. Rivers's garden, in
which two rows of a particular variety of plum33 had to
be carefully protected, as they were usually stripped of
all their buds during the winter, whilst other sorts grow-

28 Downing, ' Fruit-trees of North given in chap. x.
America,' pp. 266, 501 : in regard to the 31 Mr. Selby, in ' Mag. of Zoology and
cherry, p. 19S. Botany,' Edinburgh, vol. ii. 1838, p. 893.
29 ' Gardener's Chronicle,' 1S49, p. 755. 32 The Reine Claude de Bavay, ' Jour-
s'1 'Journal of Horticulture,' Sept. nal of Horticulture,' Dec. 27, 1864, p. 511.
26th, 1865, p. 254 ; see other references

Chap. XXI. NATURAL SELECTION. 281

ing near them escaped. The root (or enlarged stem) of
Laing's Swedish turnip is preferred by hares, and there-
fore suiters more than other varieties. Hares and rabbits
eat down common rye before St. John's-day-rye, when
both grow together.33 In the South of France, when an
orchard of almond-trees is formed, the nuts of the bitter
variety are sown, " in order that they may not be devoured
by field-mice ;" 34 so we see the use of the bitter principle
in almonds.

Other slight differences, which would be thought quite
unimportant, are no doubt sometimes of great service both
to plants and animals. The Whitesmith's gooseberry, as
formerly stated, produces its leaves later than other vari-
eties, and, as the flowers are thus left unprotected, the
fruit often fails. In one variety of the cherry, according
to Mr. Rivers,35 the petals are much curled backwards,
and in consequence of this the stigmas were observed to
be killed by a severe frost; whilst at the same time, in
another variety with incurved petals, the stigmas were
not in the least injured. The straw of the Fenton wheat
is remarkably unequal in height; and a competent ob-
server believes that this variety is highly productive,
partly because the ears, from being distributed at various
heights above the ground, are less crowded together.
The same Observer maintains that in the upright varieties
the divergent awns are serviceable by breaking the shocks
Avhen the ears are dashed together by the wind.36 If
several varieties of a plant are grown together and the
seed is indiscriminately harvested, it is clear that the har-
dier and more productive kinds will, by a sort of natural
selection, gradually prevail over the others; this takes
place, as Colonel Le Couteur believes,37 in our wheat-
fields, for, as formerly shown, no variety is quite uniform in

33 Mr. Pusey, in' Journal of R. Ajrri- 33 ' Gardener's Chron. 1SC6. p. 732.
cult. Soc.,' vol. vi. p. 179. For Swedish 36 ' Gardner's Chronicle,' 1SG2, pp.
turnips, see ' Gurd. Chron.,' 1S47, p. 91. 820, S21.

34 Godron, ' De l'Espece,' torn. ii. p. 9S. v ' On the Varieties of Wheat,' p. 59.

282 SELECTION. Chap. XXI.

character. The same thing, as I am assured by nursery-
men, would take place in our flower-gardens, if the seed
of the different varieties were not separately saved.
When the eggs of the wild and tame duck are hatched
together, the young wild ducks almost invariably perish,
from being of smaller size and not getting their fair share
of food.38

Facts in sufficient number have now been given show-
ing that natural selection often checks, but occasionally
favours, man's power of selection. These facts teach us,
in addition, a valuable lesson, namely, that we ought to
be extremely cautious in judging what characters are of
importance in a state of nature to animals and plants,
which have to struggle from the hour of their birth to
that of their death for existence, — their existence depend-
ing on conditions, about which we are profoundly igno-
rant.

Circumstances favourable to Selection by Man.

The possibility of selection rests on variability, and
this, as we shall see in the following chapters, mainly de-
pends on changed conditions of life, but is governed by
infinitely complex, and, to a great extent, unknown laws.
Domestication, even when long continued, occasionally
causes but a small amount of variability, as in the case of
the goose and turkey. The slight differences, however,
which characterise each individual animal and plant
would in most, probably in all cases, suffice for the pro-
duction of distinct races through careful and prolonged
selection. We see what selection, though acting on mere
individual differences, can effect when families of cattle,
sheep, pigeons, &c, of the same race, have been sepa-
rately bred during a number of years by different men
without any wish on their part to modify the breed. We
see the same fact in the difference between hounds bred

se Mr. Hewitt and others, in ■ Journal of Hort.,1 1S62, p. 773.

Chap. XXI. FAVOURABLE CIRCUMSTANCES. 283

for hunting in different districts,39 and in many other such
cases.

In order that selection should produce any result, it is
manifest that tho crossing of distinct races must be pre-
vented ; hence facility in pairing, as with the pigeon, is
highly favourable for the work; and difficulty in pairing,
as with cats, prevents the formation of distinct breeds.
On nearly the same principle the cattle of the small island
of Jersey have been improved in their milking qualities
" with a rapidity that could not. have been obtained in a
widely extended country like France."10 Although free
crossing is a danger on the one side which every one can
see, too close interbreeding is a hidden danger on the
other side. Unfavourable conditions of life overrule the
power of selection. Our improved heavy breeds of cattle
and sheep could not have been formed on mountainous
pastures ; nor could dray-horses have been raised on a
barren and inhospitable land such as the Falkland isl-
ands, where even the light horses of La Plata rapidly de-
crease in size. Nor could the wool of sheep have been
much increased in length within the Tropics ; yet se-
lection has kept Merino sheep nearly true under diver-
sified and unfavourable conditions of life. The power of
selection is so great, that breeds of the dog, sheep, and
poultry, of the largest and least size, long and short
beaked pigeons, and other breeds with opposite charac-
ters, have had their characteristic qualities augmented,
though treated in every way alike, being exposed to the
same climate and fed on the same food. Selection, how-
ever, is either checked or favoured by the effects of use
or habit. Our wonderfully-improved pigs could never
have been formed if they had been forced to search for
their own food; the English racehorse and greyhound
could not have been improved up to their present high
standard of excellence without constant trainin<r.

39 ' Encyclop. of Rural Sport?, p. 405.

40 Col. Le Couteur, 'Journal Uoy. Agricult. Soc.,' vol. iv. p. 43.

284 SELECTION. Chap. XXI.

As conspicuous deviations of structure occur rarely,
the improvement of each breed is generally the result, as
already remarked, of the selection of slight individual dif-
ferences. Hence the closest attention, the sharpest pow-
ers of observation, and indomitable perseverance, are
indispensable. It is, also, highly important that many
individuals of the breed which is to be improved should
be raised ; for thus there will be a better chance of the
appearance of variations in the right direction, and indi-
viduals varying in an unfavourable manner may be freely
rejected or destroyed. But that a large number of indi-
viduals should be raised, it is necessary that the condi-
tions of life should favour the propagation of the spe-
cies. Had the peacock been bred as easily as the fowl, we
should probably ere this have had many distinct races.
"We see the importance of a large number of plants, from
the fact of nursery gardeners almost always beating ama-
teurs in the exhibition of new varieties. In 1845 it Avas
estimated 41 that between 4000 and 5000 pelargoniums
were annually raised from seed in England, yet a decid-
edly improved variety is rarely obtained. At Messrs.
Carter's grounds, in Essex, where such flowers as the Lo-
belia, Nemophila, Mignonette, &c, are grown by the
acre for seed, " scarcely a season passes without some new
kinds being raised, or some improvement effected on old
kinds. 42 At Kew, as Mr. Beaton remarks, where many
seedlings of common plants are raised, " you see new
forms of Laburnums, Spiraeas, and other shrubs." 43 So
with animals : Marshall,44 in speaking of the sheep in one
part of Yorkshire, remarks, " as they belong to poor peo-
ple, and are mostly in small lots, they never can be
improved." Lord Rivers, when asked how he succeeded
in always having first-rate greyhounds, answered, " I
breed many, and hang many." This, as another man

« ' Gardener's Chronicle,' 1S45, p. 273. 43 ' Cottage Gardener,' 1860, p. 3CS.

« 'Journal of Horticulture,' 1S62, p. ** ' A Review of Reports,' 1S0S, p. 406.

157.

Chap. XXI. FAVOURABLE CIRCUMSTANCES. 285

remarks, " was the secret of his success ; and the same
will be found in exhibiting fowls, — successful competitors
breed largely, and keep the best."45 ■

It follows from this that the capacity of breeding at an
early age and at short successive intervals, as with pi-
geons, rabbits, &c, facilitates selection ; for the result is
thus soon made visible, and perseverance in the work is
encouraged. It can hardly be accidental that the great
majority of the culinary and agricultural plants which
have yielded numerous races are annuals or biennials,
which therefore are capable of rapid propagation and
thus of improvement. Sea-kale, asparagus, common and
Jerusalem artichokes, potatoes, and onions, alone are
perennials. Onions are propagated like annuals, and of
the other plants just specified, none, with the exception
of the potato, have yielded more than one or two varie-
ties. No doubt fruit-trees, which cannot be propagated
quickly by seed, have yielded a host of varieties, though
not permanent races; but these, judging from pre his-
toric remains, Avere produced at a later and more civil-
ised epoch than the races of culinary and agricultural
plants.

A species may be highly variable, but distinct races
will not be formed, if from any cause selection be not
applied. The carp is highly variable, but it would be
extremely difficult to select slight variations in fishes
whilst living in their natural state, and distinct races
have not been formed ; 4B on the other hand, a closely
allied species, the gold-fish, from being reared in glass
or open vessels, and from having been carefully attended
to by the Chinese, has yielded many races. Neither the
bee, which has been semi-domesticated from an extremely
remote period, nor the cochineal insect, which was culti-
vated by the aboriginal Mexicans, has yielded races;

46 ' Gardener's Chronicle,' 1S53, p. 45. Nat. Gdn.,' torn. iii. p. 49. On the Cochi-
*• Isidore Geoffroy St. HUaire, ' Hist. neal insect, p. 46.

286 SELECTION. Chap. XXL

and it would be impossible to match the queen-bee with
any particular drone, and most difficult to match cochi-
neal insects. Silk-moths, on the other hand, have been
subjected to rigorous selection, and have produced a
host of races. Cats, which from their nocturnal habits
cannot be selected for breeding, do not, as formerly re-
marked, yield distinct races in the same country. The
ass in England varies much in colour and size ; but it is
an animal of little value, bred by poor people; conse-
quently there has been no selection, and distinct races
have not been formed. We must not attribute the infe-
riority of our asses to climate, for in India they are of
even smaller size than in Europe. But when selection- is
brought to bear on the ass, all is changed. Near Cor-
dova, as I am informed (Feb. 1860) by Mr. W. E. Webb,
C.E., they are carefully bred, as much as 200/. having
been paid for a stallion ass, and they have been im-
mensely improved. In Kentucky, asses have been im-
ported (for breeding mules) from Spain, Malta, and
France ; these " seldom averaged more than fourteen
" hands high ; but the Kentuckians, by great care, have
" raised them up to fifteen hands, and sometimes even to
" sixteen. The prices paid for these splendid animals,
" for such they really are, will prove how much they are
" in request. One male, of great celebrity, was sold for
" upwards of one thousand pounds sterling." These
choice asses are sent to cattle-shows, one day being
given to their exhibition.47

Analogous facts have been observed with plants : the
nutmeg-tree in the Malay archipelago is highly variable,
but there has been no selection, and there are no dis-
tinct races.48 The common mignonette {Reseda odorata),
from bearing inconspicuous flowers, valued solely for

47 Capt. Marryat, quoted by Blyth in 48 Mr. Oxley, 'Journal of the Indian

'Journ. Asiatic Soe. of Bengal,' vol. Archipelago,' vol. ii., 1S48, p. 645.
xxviii. p. 229.

Chap. XXI. FAVOURABLE CIRCUMSTANCES. 287

their fragrance, "remains in the same unimproved con-
" dition as when first introduced."4' Our common for-
est-trees are very variable, as may be seen in every
extensive nursery-ground ; but as they are not valued
like fruit-trees, and as they seed late in life, no selection
has been applied to them ; consequently, as Mr. Patrick
Matthews remarks,60 they have not yielded distinct races,
leafing at different periods, growing to different sizes,
and producing timber fit for different purposes. "We have
gained only some fanciful and semi-monstrous varieties,
which no doubt appeared suddenly as we now see them.

Some botanists have argued that plants cannot have
so strong a tendency to vary as is generally supposed,
because many species long grown in botanic gardens, or
unintentionally cultivated year after year mingled with
our corn crops, have not produced distinct races ; but this
is accounted for by slight variations not having been se-
lected and propagated. Let a plant which is now grown
in a botanic garden, or any common weed, be cultivated
on a large scale, and let a sharp-sighted gardener look
out for each slight variety and sow the seed, and then,
if distinct races are not produced, the argument will be
valid.

The importance of selection is likewise shown by con-
sidering special characters. For instance, with most
breeds of fowls the form of the comb and the colour of
the plumage have been attended to, and are eminently
characteristic of each race ; but in Dorkings, fashion has
never demanded uniformity of comb or colour ; and the
utmost diversity in these respects prevails. Rose-combs,
double-combs, cup-combs, &c, and colours of all kinds,
may be seen in purely-bred and closely related Dorking
fowls, whilst other points, such as the general form of
body, and the presence of an additional toe, have been

49 Mr. Abbey, in 'Journal of Horticulture,' Dec. 1, 18C3, p. 430.
60 ' On Naval Timber,' ls31, p. 107.

288 SELECTION. Chap. XXI.

attended to, and are invariably present. It has also been
ascertained that colour can be fixed in this breed, as well
as in any other.61

During the formation or improvement of a breed, its
members will always be found to vary much in those
characters to which especial attention is directed, and of
which each slight improvement is eagerly sought and se-
lected. Thus with short-faced tumbler-pigeons, the short-
ness of the beak, shape of head and plumage, — with car-
riers, the length of the beak and wattle, — with fantails,
the tail and carriage, — with Spanish fowls, the white fiice
and comb, — with long-eared rabbits, the length of ear,
are all points which are eminently variable. So it is in
every case, and the large price paid for first-rate animals
proves the difficulty of breeding them up to the highest
standard of excellence. This subject has been discussed
by fanciers,62 and the greater prizes given for highly im-
proved breeds, in comparison with those given for old
breeds which are not now undergoing rapid improve-
ment, has been fully justified. Nathusius makes63 a simi-
lar remark when discussing the less uniform character
of improved Shorthorn cattle and of the English horse,
in comparison, for example, with the unennobled cattle
of Hungary, or with the houses of the Asiatic steppes.
This want of uniformity in the parts which at the time
are undergoing selection, chiefly depends on the strength
of the principle of reversion; but it likewise depends to
a certain extent on the continued variability of the parts
which have recently varied. That the same parts do
continue varying in the same manner we must admit,
for, if it were not so, there could be no improvement be-
yond an early standard of excellence, and we know that

61 Mr. Baily, in 'The Poultry Chroni- ber, p. 171; 1S56, January, pp. 218,

cle,' vol. ii. 1S54, p. 150. Also vol. i. p. 823.
842 ; vol. iii. p. 245. « ' Ueber Shorthorn Rindvieh,' 185^

sa ' Cottage Gardener,' 1S55, Decern- s. 51.

Chap. XXI. FAVOURABLE CIRCUMSTANCES. 289

such improvement is not only possible, but is of general
occurrence.

As a consequence of continued variability, and more
especially of reversion, all highly improved races, if ne-
glected or not subjected to incessant selection, soon de-
generate. Youatt gives a curious instance of this in
some cattle formerly kept in Glamorganshire ; but in this
case the cattle were not fed with sufficient care. Mr.
Baker, in his memoir on the Horse, sums up : " It must
"have been observed in the preceding pages that, when-
" ever there has been neglect, the breed has proportion-
" ally deteriorated." " If a considerable number of im-
proved cattle, sheep, or other animals of the same race,
were allowed to breed freely together, with no selection,
but with no change in their condition of life, there can be
no doubt that after a scoi'e or hundred generations they
would be very far from excellent of their kind ; but from
what we sec of the many common races of dogs, cattle,
fowls, pigeons, &c, which without any particular care
have long retained nearly the same character, we have no
grounds for believing that they would altogether depart
from their type.

It is a general belief amongst breeders that characters
of all kinds become fixed by Jong-continued inheritance.
But I have attempted to show in the fourteenth chapter
that this belief apparently i-esolves itself into the following
proposition, namely, that all characters whatever, whether
recently acquired or ancient, tend to be transmitted, but
that those which have already long withstood all counter-
acting influences, will, as a general rule, continue to with-
stand them, and consequently be faithfully transmitted.

** ' The Veterinary,' vol. xiii. p. 720. For the Glamorganshire cattle, see Youatt
on Cattle, p. 51.

290 SELECTION. Chap. XXI.

Tendency in Man to carry the practice of Selection to an
extreme point.

It is an important principle that in the process of se-
lection man almost invariably wishes to go to an extreme
point. Thus, in useful qualities, there is no limit to his
desire to breed certain horses and dogs as fleet as possi-
ble, and others as strong as possible ; certain kinds of
sheep for extreme fineness, and others for extreme length
of wool ; and he wishes to produce fruit, grain, tubers,
and other useful parts of plants, as large and excellent as
possible. With animals bred for amusement, the same
principle is even more powerful ; for fashion, as we see even
in our dress, always runs to extremes. This view has been
expressly admitted by fanciers. Instances were given in
the chapters on the pigeon, but here is another : Mr.
Eaton, after describing a comparatively new variety,
namely, the Archangel, remarks, " What fanciers intend
" doing with this bird I am at a loss to know, whether
"they intend to breed it down to the tumbler's head and
" beak, or carry it out to the carrier's head and beak ;
" leaving it as they found it, is not progressing." Fer-
guson, speaking of fowls, says, " their peculiarities, what-
" ever they may be, must necessarily be fully developed :
" a little peculiarity forms nought but ugliness, seeing it
>" violates the existing laws of symmetry." So Mr. Brent,
jn discussing the merits of the sub-varieties of the Belgian
canary-bird, remarks, "Fanciers always go to extremes;
" they do not admire indefinite properties." 6S

This principle, which necessarily leads to divergence
of character, explains the present state of various domes-
tic races. We can thus see how it is that race-horses
and dray-horses, greyhounds and mastiffs, which are
opposed to each other in every character, — how varieties

85 J. M.Eaton, 'A Treatise on Fancy Prize Poultry,' p. 162; Mr. Brent, in
Pigeons,' p. 82 ; Ferguson, on ' Rare and ' Cottage Gardener, Oct. I860, p. 13.

Chap. XXI. CARRIED TO AN EXTREME. 291

so distinct as Cochin-China fowls and bantams, or carrier-
pigeons with very long beaks, and tumblers with exces-
sively short beaks, have been derived from the same stock.
As each breed is slowly improved, the inferior varieties are
first neglected and finally lost. In a few cases, by the aid
of old records, or from intermediate varieties still existing
in countries where other fashions have prevailed, we are
enabled partially to trace the graduated changes through
which certain breeds have passed. Selection, whether
methodical or unconscious, always tending towards an
extreme point, together with the neglect and slow ex-
tinction of the intermediate and less-valued forms, is the
key which unlocks the mystery how man has produced
such wonderful results.

In a few instances selection, guided by utility for a
single purpose, has led to convergence of character. All
the improved and different races of the pig, as Nathusius
has well shown,66 closely approach each other in character,
in their shortened legs and muzzles, their almost hairless,
large, rounded bodies, and small tusks. We see some
degree of convergence in the similar outline of the body
in well-bred cattle belonging to distinct races.57 I know
of no other such cases.*

Continued divergence of character depends on, and is
indeed a clear proof, as previously remarked, of the same
parts continuing to vary in the same direction. The ten-
dency to mere general variability or plasticity of organ-
isation can certainly be inherited, even from one pai*ent,
as has been shown by Gartner and Kolreuter, in the pro-
duction of varying hybrids from two species, of which
one alone was variable. It is in itself probable that,
when an organ has varied in any manner, it will again
vary in the same manner, if the conditions which first
caused the being to vary remain, as far as can be judged,

89 ' Die Racen des Schweines,' I860, s. by M. de Quatrefagcs, ' Unite de l'Esvece
48. Humaine,' 1SC1, p. 119.

67 See some good remarks on this head

292 SELECTION. Chap. XXL

the same. This is either tacitly or expressly admitted by
all horticulturists: if a gardener observes one or two
additional petals in a flower, he feels confident that in a
few generations he will be able to raise a double flower,
crowded with petals. Some of the seedlings from the
weeping Moccas oak were so prostrate that they only
crawled along the ground. A seedling from the fastigate
or upright Irish yew is described as differing greatly from
the parent-form " by the exaggeration of the fastigate
habit of its branches." 68 Mr. Sheriff, who has been more
successful than any other man in raising new kinds of
wheat, remarks, " A good variety may safely be regarded
as the forerunner of a better one." 69 A great rose-
grower, Mr. Rivers, has made the same remark with re-
spect to roses. Sageret,60 who had large experience, in
speaking of the future progress of fruit-trees, observes
that the most important principle is " that the more
plants have departed from their original type, the more
they tend to depart from it." There is apparently much
truth in this remark ; for we can in no other way under-
stand the surprising amount of difference between varie-
ties in the parts or qualities which are valued, whilst
other parts retain nearly their original character.

The foregoing discussion naturally leads to the ques-
tion, what is the limit to the possible amount of variation
in any part or quality, and, consequently, is there any
limit to what selection can effect? Will a race-horse
ever be reared fleeter than Eclipse ? Can our prize-
cattle and sheep be still further improved ? "Will a goose-
berry ever weigh more than that produced by " London "
in 1852? "Will the beet-root in France yield a greater
percentage of sugar? Will future varieties of wheat
and other grain produce heavier crops than our present
varieties ? These questions cannot be positively answered ;

es Verlot, ' Des Varietes,' 1865, p. 94. 60 ' Pomologie Physiolog.,' 1830, p.

89 Mr. Patrick Sheriff, in 'Gard. 106.
Chronicle,' 1S5S, p. 771.

Chap. XX r. SELECTION". 293

but it is certain that we ought to be cautious in answer-
ing by a negative. . In some lines of variation the limit
has probably been reached. Youatt believes that the
reduction of bone in some of our sheep has already been
carried so far that it entails great delicacy of constitu-
tion.01 But seeing the great improvement within recent
times in our cattle and sheep, and especially in our pigs ;
seeing the wonderful increase in weight in our poultry of
all kinds during the last few years ; he would be a bold
man Avho would assert that perfection has been reached.
Eclipse perhaps may never be beaten until all our race-
horses have been rendered swifter, through the selection
of the best horses during many generations ; and then
the old Eclipse may possibly be eclipsed ; but, as Mr.
Wallace has remarked, there must be an ultimate limit to
the fleetness of every animal, whether under nature or
domestication ; and with the horse this limit has perhaps
been reached. Until our fields are better manured, it
may be impossible for a new variety of wheat to yield a
heavier crop. But in many cases those who are best quali-
fied to judge do not believe that the extreme point has as
yet been reached even with respect to characters which
have already been carried to a high standard of perfection.
For instance, the short-faced tumbler-pigeon has been
greatly modified ; nevertheless, according to Mr. Eaton,62
" the field is still as open for fresh competitors as it was
one hundred years ago." Over and over again it has
been said that perfection had been attained with our
flowers, but a higher standard has soon been reached.
Hardly any fruit has been more improved than the straw-
berry, yet a great authority remarks,63 " it must not be
concealed that we are far from the extreme limits at
Avhich we may arrive."

Time is an important element in the formation of our

ei Vouatt on Sheep, p. 521. e3 M. 3. de Jonghe, In ' Card. Chvon,,'

62 'A Treatise on the Almond Turn- 185S, p. 173.
Mer,' p. i.

294 SELECTION". Chap. XXI.

domestic races, as it permits innumerable individuals to
be born, and these when exposed to diversified conditions
are rendered variable. Methodical selection has been oc-
casionally practised from an ancient period to the present
day, even by semi-civilised people, and daring former
times will have produced some effect. Unconscious se-
lection will have been still more effective ; for during a
lengthened period the more valuable individual animals
will occasionally have been saved, and the less valuable
neglected. In the course, also, of time, different varieties,
especially in the less civilised countries, will have been
more or less modified through natural selection. It is
generally believed, though on this head we have little or
no evidence, that new characters in time become fixed ;
and after having long remained fixed it seems possible
that under new conditions they might again be rendered
variable.

How great the lapse of time has been since man first
domesticated animals and cultivated plants, we begin
dimly to see. When the lake-buildings of Switzerland
were inhabited during the Neolithic period, several ani-
mals were already domesticated and various plants culti-
vated. If we may judge from what we now see of the
habits of savages, it is probable that the men of the
earlier Stone period — when many great quadrupeds were
living which are now extinct, and when the face of the
country was widely different from what it now is — pos-
sessed at least some few domesticated animals, although
their remains have not as yet been discovered. If the
science of language can be trusted, the art of ploughing
and sowing the land was followed, and the chief animals
had been already domesticated, at an epoch so immensely
remote, that the Sanskrit, Greek, Latin, Gothic, Celtic,
and Sclavonic languages had not as yet diverged from
their common parent-tongue.64

•* Max Muller,' Science of Language,' 1861, p. 228.

Chap. XXL SELECTION. 295

It is scarcely possible to overrate the effects of selection
occasionally carried on in various ways and places during
thousands of generations. All that we know, and, in a
still stronger degree, all that we do not know,65 of the
history of the great majority of our breeds, even of our
more modern breeds, agrees with the view that their pro-
duction, through the action of unconscious and methodi-
cal selection, has been almost insensibly slow. When a
man attends rather more closely than is usual to the
breeding of his animals, he is almost sure to improve
them to a slight extent. They are in consequence valued
in his immediate neighbourhood, and are bred by others ;
and their characteristic features, whatever these may be,
will then slowly but steadily be increased, sometimes by
methodical and almost always by unconscious selection.
At last a strain, deserving to be called a sub-variety, be-
comes a little more widely known, receives a local name,
and spreads. The spreading will have been extremely
slow during ancient and less civilised times, but now is
rapid. By the time that the new breed had assumed a
somewhat distinct character, its history, hardly noticed
at the time, will have been completely forgotten ; for, as
Low remarks,68 " we know how quickly the memory of
such events is effaced."

As soon as a new breed is thus formed, it is liable
through the same process to break up into new strains
and sub-varieties. For different varieties are suited for,
and are valued under, different circumstances. Fashion
changes, but, should a fashion last for even a moderate
length of time, so strong is the principle of inheritance,
that some effect will probably be impressed on the breed.
Thus varieties go on increasing in number, and history
shows us how wonderfully they have increased since the
earliest records.67 As each new variety is produced, the

es Youatt on Cattle, pp. 116, 128. ,T Volz, ' Beitrage zur Kultnrgeschich-

ea ■ Domesticated Animals,' p. 1SS. te,' 1S52, s. 99 et passim.

296 SELECTION. Chap. XXI.

earlier, intermediate, and less valuable forms Vill be neg-
lected, and perish. When a breed, from not being valued,
is kept in small numbers, its extinction almost inevitably
follows sooner or later, either from accidental causes of
destruction or from close interbreeding ; and this is an
event which, in the case of well-marked bi-eeds, excites
attention. The birth or production of a new domestic race
is so slow a process that it escapes notice ; its death or
destruction is comparatively sudden, is often recorded,
and when too late sometimes regretted.

Several authors have drawn a wide distinction be-
tween artificial and natural races. The latter are more
uniform in character, possessing in a high degree the
character of natural species, and are of ancient origin.
They are generally found in less civilised countries, and
have probably been largely modified by natural selection,
and only to a small extent by man's unconscious and me-
thodical selection. They have, also, during a long period,
been directly acted on by the physical conditions of the
countries which they inhabit. The so-called artificial
races, on the other hand, are not so uniform in character ;
some have a semi-monstrous character, such as " the wry-
legged terriers so useful in rabbit-shooting," 68 turnspit
dogs, ancon sheep, niata oxen, Polish fowls, fantail-
pigeons, &c. ; their characteristic features have generally
been acquired suddenly, though subsequently increased
in many cases by careful selection. Other races, which
certainly must be called artificial, for they have been
largely modified by methodical selection and by crossing,
as the English race-horse, terrier-dogs, the English game-
cock, Antwerp carrier-pigeons, &c, nevertheless cannot
be said to have an unnatural appearance ; and no distinct
line, as it seems to me, can be drawn between natural
and artificial races.
It is not surprising that domestic races should gener-

68 Blaine, ' Encyclop. of Rural Sports,1 p. 213.

Chap. XXI. SELECTION. 297

ally present a different aspect from natural species. Man
selects and propagates modifications solely for his own
use or fancy, and not for the creature's own good. His
attention is struck by strongly marked modifications,
which have appeared suddenly, due to some great dis-
turbing cause in the organisation. He attends almost
exclusively to external characters ; and when he succeeds
in modifying internal organs, — when for instance he
reduces the bones and offal, or loads the viscera with fat,
or gives early maturity, &c, — the chances are strong
that he will at the same time weaken the constitution.
On the other hand, when an animal has to struggle
throughout its life with many competitors and enemies,
under circumstances inconceivably complex and liable to
change, modifications of the most varied nature — in the
internal organs as well as in external characters, in the
functions and mutual relations of parts — will be rigorous-
ly tested, preserved, or rejected. Natural selection often
checks man's comparatively feeble and capricious at-
tempts at improvement ; and if this were not so, the
result of his work, and of nature's work, would be even
still more different. Nevertheless, we must not overrate
the amount of difference between natural species and
domestic races; the most experienced naturalists have
often disputed whether the latter are descended from one
or from several aboriginal stocks, and this clearly shows
that there is no palpable difference between species and
races.

Domestic races propagate their kind far more truly,
and endure for much longer periods, than most natu-
ralists are willing to admit. Breeders feel no doubt on
this head ; ask a man who has long reared Shorthorn or
Hereford cattle, Leicester or Southdown sheep, Spanish
or Game poultry, tumbler or carrier-pigeons, whether
these races may not have been derived from common
progenitors, and he will probably laugh you to scorn.
The breeder admits that he may hope to produce sheep

298 SELECTION. Chap. XXI.

with finer or longer wool and with better carcases, or
handsomer fowls, or carrier-pigeons with beaks just per-
ceptibly longer to the practised eye, and thus be success-
ful at an exhibition. Thus far he will go, but no farther.
He does not reflect on what follows from adding up dur-
ing a long course of time many, slight, successive modi-
fications ; nor does he reflect on the former existence of
numerous varieties connecting the links in each divergent
line of descent. He concludes, as was shown in the
earlier chapters, that all the chief breeds to which he has
long attended are aboriginal productions. The syste-
matic naturalist, on the other hand, who generally knows
nothing of the art of breeding, who does not pretend to
know how and when the several domestic races were
formed, who cannot have seen the intermediate grada-
tions, for they do not now exist, nevertheless feels no
doubt that these races are sprung from a single source.
But ask him whether the closely allied natural species
which he has studied may not have descended from a
common progenitor, and he in his turn will perhaps reject
the notion with scorn. Thus the naturalist and breeder
may mutually learn a useful lesson from each other.

Summary on Selection by Man. — There can be no
doubt that methodical selection has effected and will
effect wonderful results. It was occasionally practised in
ancient times, and is still practised by semi-civilised
people. Characters of the highest importance, and others
of trifling value, have been attended to, and modified.
I need not here repeat what has been so often said on the
part which unconscious selection has played ; we see its
power in the difference between flocks which have been
separately bred, and in the slow changes, as circumstan-
ces have slowly changed, which many animals have un-
dergone in the same country, or when ti*ansported into
a foreign land. We see the combined effects of method-
ical and unconscious selection in the great amount of
difference between vai-ieties in those parts or qualities

Chap. XXL SELECTION. 299

which are valued by man, in comparison with those
which are not valued, and consequently have not been
attended to. Natural selection often determines man's
power of selection. "We sometimes err in imagining that
characters, which are considered as unimportant by the
systematic naturalist, could not be affected by the strug-
gle for existence, and therefore be acted on by natural
selection ; but striking cases have been given, showing
how great an error this is.

The possibility of selection coming into action rests on
variability ; and this is mainly caused, as we shall here
after see, by changes in the conditions of life. Selection
is sometimes rendered difficult, or even impossible, by
the conditions being opposed to the desired character or
quality. It is sometimes checked by the lessened fertility
and weakened constitution which follow from long-conti-
nued close interbreeding. That methodical selection may
be successful, the closest attention and discernment,
combined with unwearied patience, are absolutely neces-
sary; and the same qualities, though not indispensable,
are highly serviceable in the case of unconscious selec-
tion. It is almost necessary that a large number of indi-
viduals should be reared ; for thus there will be a fair
chance of variations of the desired nature arising, and
every individual with the slightest blemish or in any de-
gree inferior may be freely rejected. Hence length of
time is an important element of success. Thus, also, pro-
pagation at an early age and at short intervals favours the
work. Facility in pairing animals, or their inhabiting a
confined area, is advantageous as a check to free crossing.
Whenever and wherever selection is not practised, dis-
tinct races are not formed. When any one part of the
body or quality is not attended to, it remains either un-
changed or varies in a fluctuating manner, whilst at the
same time other parts and other qualities may become
permanently and greatly modified. But from the ten-
dency to reversion and to continued variability, those

300 SELECTION. Chap. XXI.

parts or organs which are now undergoing rapid improve-
ment through selection, are likewise found to vary much.
Consequently highly-bred animals, when neglected, soon
degenerate ; but we have no reason to believe that the
effects of long-continued selection would, if the conditions
of life remained the same, be soon and completely lost.

Man always tends to go to an extreme point in the se-
lection, whether methodical or unconscious, of all useful
and pleasing qualities. This is an important principle,
as it leads to continued divergence, and in some rare
cases to convergence of character. The possibility of
continued divergence rests on the tendency in each part
or organ to go on varying in the same manner in which
it has already vai'ied ; and that this occurs, is proved by
the steady and gradual improvement of many animals
and plants during lengthened periods. The principle
of divergence of character, combined with the neg-
lect and final extinction of all previous, less-valued, and
intermediate varieties, explains the amount of difference
and the distinctness of our several races. Although we
may have reached the utmost limit to which certain cha-
racters can be modified, yet we are far from having
reached, as we have good reason to believe, the limit in
the majority of cases. Finally, from the difference be-
tween selection as carried on by man and by nature, we
can understand how it is that domestic races often,
though by no means always, differ in general aspect from
closely allied natural species.

Throughout this chapter and elsewhere I have spoken
of selection as the paramount power, yet its action abso-
lutely depends on what we in our ignorance call sponta-
neous or accidental variability. Let an architect be
compelled to build an edifice with uncut stones, fallen
from a precipice. The shape of each fragment may be
called accidental; yet the shape of each has been deter-
mined by the force of gravity, the nature of the rock, and
the slope of the precipice, — events and circumstances, all

Cuap. XXL SELECTION. 301

of which depend on natural laws ; but there is no relation
between these laws and the purpose for which each frag-
ment is used by the builder. In the same manner the
variations of each creature are determined by fixed and
immutable laws ;• but these bear no relation to the living
structure which is slowly built up through the power of
selection, whether this be natural or artificial selection.

If our architect succeeded in rearing a noble edifice,
using the rough wedge-shaped fragments for the arches,
the longer stones for the lintels, and so forth, we should
admire his skill even in a higher degree than if he had
used stones shaped for the purpose. So it is with selec-
tion, whether applied by man or by nature ; for though
variability is indispensably necessary, yet, when we look
at some highly complex and excellently adapted organ-
ism, variability sinks to a quite subordinate position in
importance in comparison with selection, in the same
manner as the shape of each fragment used by our sup-
posed architect is unimportant in comparison with his
skill.

302 CAUSES OF VAEIABILITY. Chap. XXJI.

CHAPTER XXII.

CAUSES OF VARIABILITY.

VAEIABILITY DOES NOT NECESSARILY ACCOMPANY REPRODUCTION —
CAUSES ASSIGNED BY VARIOUS AUTHORS — INDIVIDUAL DIFFER-
ENCES — VARIABILITY OF EVERY KIND DUE TO CHANGED CONDI-
TIONS OF LIFE — ON THE NATURE OF SUCH CHANGES — CLIMATE,
FOOD, EXCESS OF NUTRIMENT — SLIGHT CHANGES SUFFICIENT —
EFFECTS OF GRAFTING ON THE VARIABILITY OF SEEDLING-TREES
— DOMESTIC PRODUCTIONS BECOME HABITUATED TO CHANGED
CONDITIONS — ON THE ACCUMULATIVE ACTION OF CHANGED CON-
DITIONS — CLOSE INTERBREEDING AND THE IMAGINATION OF THE
MOTHER SUPPOSED TO CAUSE VARIABILITY — CROSSING AS A CAUSE
OF THE APPEARANCE OF NEW CHARACTERS — VARIABILITY FROM
THE COMMINGLING OF CHARACTERS AND FROM REVERSION — ON
THE MANNER AND PERIOD OF ACTION OF THE CAUSES WHICH
EITHER DIRECTLY, OR INDIRECTLY THROUGH THE REPRODUCTIVE
SYSTEM, INDUCE VARIABILITY,

We will now consider, as far as we can, the causes of
the almost universal variability of our domesticated pro-
ductions. The subject is an obscure one ; but it may be
useful to probe our ignorance. Some authors, for instance
Dr. Prosper Lucas, look at variability as a necessary con-
tingent on reproduction, and as much an aboriginal law,
as growth or inheritance. Others have of late encouraged,
perhaps unintentionally, this view by speaking of in-
heritance and variability as equal and antagonistic prin-
ciples. Pallas maintained, and he has had some followers,
that variability depends exclusively on the crossing of
primordially distinct forms. Other authors attribute the
tendency to variability to an excess of food, and with
animals to an excess relatively to the amount of exercise

Chap. xxii. CAUSES OF VARIABILITY. 303

taken, or again to the effects of a more genial climate.
That these causes are all effective is highly probable.
But Ave must, I think, take a broader view, and conclude
that organic beings, when subjected during several genera-
tions to any change whatever in their conditions, tend to
vary ; the kind of variation which ensues depending in a
far higher degree on the nature or constitution of the be-
ing, than on the nature of the changed conditions.

Those authors who believe that it is a law of nature
that each individual should differ in some slight degree
from every other, may maintain, apparently with truth,
that this is the fact, not only with all domesticated animals
and cultivated plants, but likewise with all organic beings
in a state of nature. The Laplander by long practice
knows and gives a name to each reindeer, though as Lin-
nams remarks, " to distinguish one from another among
such multitudes was beyond my comprehension, for they
were like ants on an ant-hill." In Germany shepherds
have won wagers by recognising each sheep in a flock of
a hundred, which they had never seen until the previous
fortnight. This power of discrimination, however, is as
nothing compared to that which some florists have ac-
quired. Verlot mentions a gardener who could dis-
tinguish 150 kinds of camellia, when not in flower; and
it has been positively asserted that the famous old Dutch
florist Voorhelm, who kept above 1200 varieties of the
hyacinth, Avas hardly ever deceived in knowing each
variety by the bulb alone. Hence we must conclude that
the bulbs of the hyacinth and the branches and leaves of
the camellia, though appearing to an unpractised eye ab-
solutely undistinguishable, yet really differ.1

As Linnams has compared the reindeer in number to
ants, I may add that each ant knows its fellow of the

> ' Des Jacinthes,' Ac, Amsterdam, E. Smith, vol. i. p. 314. The statement

176S, p. 43; Verlot, ' Des Varietes,' Ac, in regard to German shepherds Is given

p. 86. On the reindeer, see Linnieus, on the authority of Dr. Weinland.
' Tour in Lapland,' translated by Sir J.

804 CAUSES OF VAEIABILITY. Chap. XXII.

same community. Several times I carried ants of the
same species (Formica rufa) from one ant-hill to another,
inhabited apparently by tens of thousands of ants;, but
the strangers were instantly detected and killed. I then
put some ants taken from a very large nest into a bottle
strongly perfumed with assafoetida, and after an interval
of twenty-four hours returned them to their home ; they
were at first threatened by their fellows, but were soon
recognised and allowed to pass. Hence each ant certainly
recognises, independently of odour, its fellow ; and if all
the ants of the same community have not some counter-
sign or watchword, they must present to each other's
senses some distinguishable character.

The dissimilarity of brothers or sisters of the same
family, and of seedlings from the same capsule, may be in
part accounted for by the unequal blending of the cha-
racters of the two parents, and by the more or less com-
plete recovery through reversion of ancestral characters
on either side ; but we thus only push the difficulty fur-
ther back in time, for what made the parents or their pro-
genitors different? Hence the belief2 that an innate ten-

2 Mullev's ' Physiology,1 Eng. transla- venait de recevoir de ce frere alors a

tion, vol. ii. p. 16G2. 'With respect to the Vienne, et qui lui ecrivait en effet — ' J'ai

similarity of twins in constitution, Dr. mon ophthalmie, tu dois avoir la tienne.'

William Ogle has given me the following Quelquesingulierquececipuisseparaitre,

extract from Professor Trousseau's Lee- le fait non est pas moins exact : on ne me

tures (' Clinique Medicale,' torn. i. p. l'a pas raconte, je l'ai vu, et j'en ai vu

523), in which a curious case is recorded : d'autres analogues dans ma pratique.

— "J'ai donne mes soins a deux freres Ces deux jumeaux etaient aussi tous

jumeaux, tous deux si extraordinaire- deux asthmatiques, et asthmatiques a

ment ressemblants qu'il m'etait impos- un effroyable degre. Originaires de Mar-

sible de les reconnaitre, a moins de les seille, ils n'ont jamais pu demeurer dans

voir l'un a cote de l'autre. Cette res- cette ville,ou leurs interets les appelaient

semblance physique s'etendait plus loin: souvent, sans etrc pris de leurs acces;

ils avaient, permettez-moi l'expression, jamais ils n'en eprouvaient a Paris. Bien

une similitude pathologique plus re- mieux, il leur suffisait de gagner Toulon

marquable encore. Ainsi l'un d'eux que pour etre gueris de leurs attaques de

je voyais aux neothermes a Paris malade Marseille. Voyageant sans cesse et dans

d'une ophthalmie rhumatismale me di- tous pays pour leurs affaires, ils avaient

sait, ' En ce moment mon frere doit avoir remarque que certaines localites leur

une ophthalmie comme la mienne ;' et Etaient funestes, que dans d'autres ils

comme je m'etais recrie, il me montrait etaient exempts de tout phenomene

quelques jours apres une lettre qu'il d'oppression."

Ciiap. XXII. CAUSES OF VARIABILITY. 305

dcncy to vary exists, independently of external conditions,
seems at first sight probable. But even the seeds nurtured
in the same capsule arc not subjected to absolutely uni-
form conditions, as they draw their nourishment from
different points ; and Ave shall see in a future chapter that
this difference sometimes suffices greatly to affect the
character of the future plant. The less close similarity
of the successive children of the same family in com-
parison with human twins, which often resemble each
other in external appearance, mental disposition, and con-
stitution, in so extraordinary a manner, apparently proves
that the state of the parents at the exact period of con-
ception, or the nature of the subsequent embryonic de-
velopment, has a direct and powerful influence on the
character of the offspring. Nevertheless, when we re-
flect on the individual differences between organic beings
in a state of nature, as shown by every wild animal know-
ing its mate ; and when we reflect on the infinite diversity
of the many varieties of our domesticated productions,
we may well be inclined to exclaim, though falsely as I
believe, that Variability must be looked at as an ultimate
fact, necessarily contingent on reproduction.

Those authors who adopt tbis latter view would pro-
bably deny that each separate variation has its own pro-
per exciting cause. Although we can seldom trace the
precise relation between cause and effect, yet the consi-
derations presently to be given lead to the conclusion
that each modification must have its^>wn distinct cause.
When we hear of an infant born, for instance, with a
crooked finger, a misplaced tooth, or other slight devia-
tion of structure, it is difficult to bring the conviction
home to the mind that such abnormal cases are the re-
sult of fixed laws, and not of what we blindly call acci-
dent. Under this point of view the following case, which
has been carefully examined and communicated to me by
Dr. William Ogle, is highly instructive. Two girls, born
as twins, and in all respects extremely alike, had their

306 CAUSES OF VAEIABILITY. Chap. XXH.

little fingers on both hands crooked; and in both chil-
dren the second bicuspid tooth in the upper jaw, of the
second dentition, was misplaced ; for these teeth, instead
of standing in a line with the others, grew from the roof
of the mouth behind the first bicuspids. Neither the
parents nor any other member of the family had exhibited
any similar peculiarity. Now, as both these children
were affected in exactly the same manner by both devia-
tions of structure, the idea of accident is at once excluded ;
and we are compelled to admit that there must have ex-
isted some precise and sufficient cause which, if it had
occurred a hundred times, would have affected a hundred
children.

We will now consider the general arguments, which
appear to me to have great weight, in favor of the view
that valuations of all kinds and degrees are directly or
indirectly caused by the conditions of life to which each
being, and more especially its ancestors, have been ex-
posed.

No one doubts that domesticated productions are more
variable than organic beings which have never been re-
moved from their natural conditions. Monstrosities gra-
duate so insensibly into mere variations that it is impos-
sible to separate them ; and all those who have studied
monstrosities believe that they are far commoner with
domesticated than with wild animals and plants ; 3 and
in the case of plants, monstrosities would be equally no-
ticeable in the natural as in the cultivated state. Under
nature, the individuals of the same species are exposed
to nearly uniforn conditions, for they are rigorously kept
to their proper places by a host of competing animals
and plants ; they have, also, long been habituated to
their conditions of life ; but it cannot be said that they
are subject to quite uniform conditions, and they are lia-

s Isid. Geoffroy St. Hilaire, ' Hist, des Tandon, "Teratologic Vegetale,' 1841, p.
Anomalies,' torn. iii. p. 352 ; Moquin- 115.

Chap. XXII. CAUSES OF VARIABILITY. 307

ble to a certain amount of variation. The circumstances
mder which our domestic productions are reared are
widely, different : they are protected from competition ;
-hey have not only been removed from their natural con-
ditions and often from their native land, but they are
frequently carried from district to district, where they
are treated differently, so that they never remain during
a considerable length of time exposed to closely similar
conditions. In conformity with this, all our domesti-
cated productions, with the rarest exceptions, vary far
more than natural species. The hive-bee, which feeds it-
self and follows in most respects its natural habits of life,
is the least variable of all domesticated animals, and pro-
bably the goose is the next least variable ; but even the
goose varies more than almost any wild bird, so that it
cannot be affiliated with perfect certainty to any natural
species. Hardly a single plant can be named, which has
long been cultivated and propagated by seed, that is not
highly variable ; common rye {Secede cereale) has afforded
fewer and less marked varieties than almost any other
cultivated plant ; 4 but it may be doubted whether the
variations of this, the least valuable of all our cereals,
have been closely observed.

Bud-variation, which was fully discussed in a former
chapter, shows us that variability may be quite indepen-
dent of seminal reproduction, and likewise a reversion to
long-lost ancestral characters. No one will maintain that
the sudden appearance of a moss-rose on a Provence-rose
is a return to a former state, for mossiness of the calyx
has been observed in no natural species ; the same argu-
ment is applicable to variegated and laciniated leaves ;
nor can the appearance of nectarines on peach-trees be
accounted for with any probability on the principle of
reversion. But bud-variations more immediately con-
cern us, as they occur far more frequently on plants which

Metzger, 'Die Getreldearten,' 1S41, s. 39.

308 CAUSES OF VARIABILITY. Chap. XXII.

have been highly cultivated during a length of time, than
on other and less highly cultivated plants ; and very few
well-marked instances have been observed with .plants
growing under strictly natural conditions. I have given
one instance of an ash-tree growing in a gentlemau's plea-
sure-grounds ; and occasionally there may be seen, on
beech and other trees, twigs leafing at a different period
from the other branches. But our forest trees in England
can hardly be considered as living under strictly natural
conditions ; the seedlings are raised and protected in nur-
sery-grounds, and must often be transplanted into places
where wild trees of the kind would not naturally grow.
It would be esteemed a prodigy if a dog-rose growing in
a hedge produced by bud-variation a moss-rose, or a wild
bullace or wild cherry-tree yielded a branch bearing fruit
of a different shape and colour from the ordinary fruit.
The prodigy would be enhanced if these varying branches
were found capable of propagation, not only by grafts,
but sometimes by seed ; yet analogous cases have oc-
curred with many of our highly cultivated trees and
herbs.

These several considerations alone render it probable
that variability of every kind is directly or indirectly
caused by changed conditions of life. Or, to put the case
under ■another point of view, if it were possible to expose
all the individuals of a species during many generations
to absolutely uniform conditions of life, there would be no
variability.

On the Nature of the Changes in the Conditions of Life
which induce Variability.
•
From a remote period to the present day, under climates
and circumstances as different as it is possible to conceive,
organic beings of all kinds, when domesticated or culti-
vated, have varied. We see this with the many domestic
races of quadrupeds and birds belonging to different

•

Chap. XXII. CAUSES OF VARIABILITY. 309

orders, with gold-fish and silk-Avorms, with plants of
many kinds, raised in various quarters of the world. In
the deserts of northern Africa the date-palm has yielded
thirty-eight varieties ; in the fertile plains of India it is
notorious how many varieties of rice and of a host of other
plants exist; in a single Polynesian island, twenty-four
varieties of the bread-fruit, the same number of the ba-
nana, and twenty-two varieties of the arum, are cultivated
by the natives ; the mulberry-tree in India and Europe
has yielded many varieties serving as food for the silk-
worm ; and in China sixty-three varieties of the bamboo
are used for various domestic purposes.5 These facts
alone, and innumerable others could be added, indicate
that a change of almost any kind in the conditions of life
suffices to cause variability — different changes acting on
different organisms.

Andrew Knight ° attributed the variation of both ani-
mals and plants to a more abundant supply of nourish-
ment, or to a more favourable climate, than that natural
to the species. A more genial climate, however, is far
from necessary ; the kidney-bean, which is often injured
by our spring frosts, and peaches, which require the pro-
tection of a wall, have varied much in England, as has
the orange-tree in northern Italy, where it is barely able
to exist.7 Nor can we overlook the fact, though not imme-
diately connected with our present subject, that the plants
and shells of the arctic regions are eminently variable.8
Moreover, it does not appear that a change of climate,

6 On the date-palm, see Vogel, ' Annals ' Chinese Empire,' vol. ii. p. 307.

and Mag. of Nat. Hist.,' 1S54,p. 460. On « 'Treatise on the Culture of the

Indian varieties, Dr. F. Hamilton, 'Trans- Apple,' &c, p. 3.

act. Linn. Soc.,' vol. xiv. p. 296. On the 7 Gallesio, ' Teoria della Riproduiione

varieties cultivated in Tahiti, see Dr. Ben- Veg.,' p. 125.

nett, in Loudon's ' Mag. of X. Hist.,' vol. 8 See Dr. Hooker's Memoir on Arctic

v., 1883, p. 484 Also Ellis, 'Polynesian Plants in 'Linn. Transact.,' vol. xxiii.

Researches,' vol. i. pp. 3T5, 3T0. On part ii. Mr. Woodward, and a higher

twenty varieties of the Pandanus and authority cannot he quoted, speaks of

other trees in the Marianne Island, see the Arctic mollusca (in his 'Rudimentary

'Hooker's* Miscellany,' vol. i. p. 303. Treatise,' 1856, p. 355) as remarkably

On the bamboo in China, see Huc'3 subject to variation.

310 CAUSES OF VARIABILITY. Chap. TtXII.

whether more or less genial, is one of the most potent
causes of variability ; for in regard to plants Alph. De
Candolle, in his ' Geographie Botanique,' repeatedly
shows that the native country of a plant, where in most
cases it has been longest cultivated, is that where it has
yielded the greatest number of varieties.

It is doubtful whether a change in the nature of the
food is a potent cause of variability. Scarcely any do-
mesticated animal has varied more than the pigeon or
the fowl, but their food, especially that of highly-bred
pigeons, is generally the same. Nor can our cattle and
sheep have been subjected to any great change in this
respect. But in all these cases the food probably is much
less varied in kind than that which was consumed by the
species in its natural state.9

Of all the causes which induce variability, excess of
food, whether or not changed in nature, is probably the
most powerful. This view was held with regard to
plants by Andrew Knight, and is now held by Schleiden,
more especially in reference to the inorganic elements of
the food.10 In order to give a plant more food it suffices
in most cases to grow it separately, and thus prevent
other plants robbing its roots. It is surprising, as I have
often seen, how vigorously our common wild plants flou-
rish when planted by themselves, though not in highly
manured land. Growing plants separately is, in fact, the
first step in cultivation. We see the convei'se of the be-
lief that excess of food induces variability in the follow-
ing statement by a great raiser of seeds of all kinds.11
" It is a rule invariably with us, when we desire to keep
" a true stock of any one kind of seed, to grow it on poor

9 Bechstein, in his ' Naturgescliicbte lated by Henfrey, 184S, p. 169. See alst

der Stubenvogel,' 1840, s. 233, has some Alex. Braun, in 'Bot. Memoirs,' Ray

good remarks on this subject. He states Soc., 1853, p. 313.

that his canary-birds varied in colour, ll Messrs. Hardy and Son, of Maldon

though kept on uniform food. in ' Gard. Chronicle,' 1856, p. 458.

io «xhe Plant,' by Schleiden, trans-

Chap. XXII. CAUSES OF VARIABILITY. 311

" land without dung ; but when we grow for quantity,
" we act contrary, and sometimes have dearly to repent
'< of it."

In the case of animals the want of a proper amount of
exercise, as Bechstein has remarked, has perhaps played,
independently of the direct effects of the disuse of any
particular organ, an important part in causing variability.
We can see in a vague manner that, when the organised
and nutrient fluids of the body are not used during
growth, or by the wear and tear of the tissues, they will
be in excess ; and as growth, nutrition, and reproduction
are intimately allied processes, this superfluity might dis-
turb the due and proper action of the reproductive or-
gans, and consequently affect the character of the future
offspring. But it may be argued that neither an excess
of food nor a superfluity in the organised fluids of the
body necessarily induces variability. The goose and the
turkey have been Avell fed for many generations, yet have
varied very little. Our fruit-trees and culinary plants,
which are so variable, have been cultivated from an
ancient period, and, though they probably still receive
more nutriment than in their natural state, yet they must
have received during many generations nearly the same
amount ; and it might be thSught that they would have
become habituated to the excess. Nevertheless, on the
whole, Knight's view, that excess of food is one of the
most potent causes of variability, appears, as far as I can
judge, probable.

Whether or not our various cultivated plants have re-
ceived nutriment in excess, all have been exposed to
changes of various kinds. Fruit-trees are grafted on dif-
ferent stocks, and grown in various soils. The seeds of
culinary and agricultural plants are carried from place to
place ; and during the last century the rotation of our
crops and the manures used have been greatly changed.

Slight changes of treatment often suffice to induce va-
riability. The simple fact of almost all our cultivated

312 CAUSES OF VAEIABILITY. Chap. XXII.

plants and domesticated animals having varied in all
places and at all times, leads to this conclusion. Seeds
taken from common English forest-trees, grown under
their native climate, not highly manured or otherwise
artificially treated, yield seedlings which vary much, as
may be seen in every extensive seed-bed. I have shown
in a former chapter what a number of well-marked and
singular varieties the thorn ( Crataegus oxyacanthd) has
produced ; yet this tree has been subjected to hardly any
cultivation. In Staffordshire I carefully examined a large
number of two British plants, namely, Geranium fihceum
and Pyrenaicum, which have never been highly culti-
vated. These plants had spread spontaneously by seed
from a common garden into an open plantation ; and the
seedlings varied in almost every single character, both in
their flowers and foliage, to a degree which I have never
seen exceeded ; yet they could not have been exposed to
any great change in their conditions.

With respect to animals, Azara has remarked with
much surprise,12 that, whilst the feral horses on the Pam-
pas are always of one of three colours, and the cattle al-
ways of a uniform colour, yet these animals, when bred
on the unenclosed estancias, though kept in a state which
can hardly be called domesticated, and apparently ex-
posed to almost identically the same conditions as when
they are feral, nevertheless display a great diversity of
colour. So again in India several species of fresh-water
fish are only so far treated artificially, that they are
reared in great tanks ; but this small change is sufficient
to induce much variability.13

Some facts on the effects of grafting, in regard to the
variability of trees, deserve attention. Cabanis asserts
that when certain pears are grafted on the quince, their

12 ' Quadrupedes du Paraguay,' 1801, 'Asiatic Researches,' vol. xix. part ii.,
torn. ii. p. 319. 1839, pp. 266, 268, 318.

13 M'Clelland on Indian Cyprinidae,

Chap. XXII. CAUSES OF VARIABILITY. 313

seeds yield more varieties than do the seeds of the same
variety of pear when grafted on the wild pear.14 But as
the pear and quince are distinct species, though so closely
related that the one can be readily grafted and succeeds
admirably on the other, the fact of variability being thus
caused is not surprising ; we are, however, here enabled
to see the cause, namely, the different nature of the stock
with its roots and the rest of the tree. Several North
American varieties of the plum and peach are well known
to reproduce themselves truly by seed ; but Downing
asserts,15 " that when a graft is taken from one of these
" trees and placed upon another stock, this grafted tree
" is found to lose its singular property of producing the
" same variety by seed, and becomes like all other worked
"trees;" — that is, its seedlings become highly variable.
Another case is worth giving: the Lalande variety of
the walnut-tree leafs between April 20th and May 15th,
and its seedlings invariably inherit the same habit ; whilst
several other varieties of the walnut leaf in June. Now,
if seedlings are raised from the May-leafing Lalande vari-
ety, grafted on another May-leafing variety, though both
stock and graft have the same early habit of leafing, yet
the seedlings leaf at various times, even as late as the 5th
of June.16 Such facts as these are well fitted to show,
on what obscure and slight causes variability rests.

I may here just allude to the appearance of new and valuable
varieties of fruit-trees and of wheat in woods in waste places, which
at first sight seems a most anomalous circumstance. In France a
considerable number of the best pears have been discovered in
woods ; and this has occurred so frequently, that Poiteau asserts
that " improved varieties of our cultivated fruits rarely originate
with nurserymen." In England, on the other hand, no instance of

14 Quoted by Sageret, ' Pom. Phys.,' I7 M. Alexis Jordan mentions four ex-

1880, p. 43. client pears found in woods in France,

16 ' jlie Fruits of America,' 1S45, p. 5. and alludes to others ('Mem. Acad, de

11 ML Cardan, in 'Comptcs Rendus," I,yon,' torn. ii. 1852, p. 159). Poiteau's

Dec. 1S4S, quoted in'Gard. Chronicle,' remark is quoted in ' Gardener's Mag.,'

1&A9, p. 101. voL iv., 1828, p. 885. Se* ' Gard. Chronl-

314 CAUSES OF VARIABILITY. Chap. XXII.

a good pear having been found wild lias been recorded ; and Mr,
Rivers informs me that lie knows of only one instance with apples,
namely, the Bess Poole, which was discovered in a wood in Notting-
hamshire. This difference between the two countries may be in
part accounted for by the more favourable climate of France, but
chiefly from the great number of seedlings which spring up there
in the woods. I infer that this is the case from a remark made by
a French gardener,18 who regards it as a national calamity that such
a number of pear-trees are periodically cut down for firewood, be-
fore they have borne fruit. The new varieties which thus spring
up in the woods, though they cannot have received any excess of
nutriment, will have been exposed to abruptly changed conditions,
but whether this is the cause of their production is very doubtful.
These varieties, however, are probably all descended 19 from old
cultivated kinds growing in adjoining orchards, — a circumstance
which will account for their variability ; and out of a vast number
of varying trees there will always be a good chance of the appear-
ance of a valuable kind. In North America, where fruit-trees 'fre-
quently spring up in waste places, the Washington pear was found
in a hedge, and the Emperor peach in a wood.20

With respect to wheat, some writers have spoken 21 as if it were
an ordinary event for new varieties to be found in waste places ; the
Fenton wheat was certainly discovered growing on a pile of basaltic
detritus in a quarry, but in such a situation the plant would proba-
bly receive a sufficient amount of nutriment. The Chidham wheat
was raised from an ear found on a hedge ; and Hunter's wheat was
discovered by the roadside in Scotland, but it is not said that this
latter variety grew where it was found.23

Whether our domestic productions would ever become
so completely habituated to the conditions under which
they now live, as to cease varying, we have no sufficient
means forjudging. But, in fact, our domestic productions

cle,' 1S62, p. 335, for another case of a woods seedlings resembling all the chief

new variety of the pear found in a hedge cultivated races of both the pear and ap-

in France. Also for another case, me Lou- pie. Van Mons, however, looked at these

don's 'Encyclop. of Gardening,' p. 901. wild varieties as aboriginal species.

Mr. Rivers has given me similar informa- 20 Downing, 'Fruit-trees of North

tion. America,' p. 422 ; Foley, in ' Transact.

18 Duval, ' Hist, du Poirier,' 1S49, p. 2. Hort. Soc.,' voL vi. p. 412.

19 I infer that this is the fact from 21 ' Gard. Chronicle,' 1847, p. 244.

V an Mons' statement (' Arbres Fruitiers,' 2a ' Gardener's Chronicle,*. 1841, p.

1S35, torn. i. p. 446) that he finds in the 3S3; 1850, p. 700 ; 1854, p. C50.

Chap. XXII. CAUSES OF VARIABILITY. 315

are never exposed for a great length of time to uniform
conditions, and it is certain that our most anciently culti-
vated plants, as well as animals, still go on varying, for
all have recently undergone marked improvement. In
some few cases, however, plants have become habituated
to new conditions. Thus Metzger, who cultivated in Ger-
many during many years numerous varieties of wheat,
brought from different countries,23 states that some kinds
were at first extremely variable, but gradually, in one
instance after an interval of twenty-five years, became
constant ; and it does not appear that this resulted from
the selection of the more constant forms.

On the Accumulative Action of changed Conditions of
Life. — We have good grounds for believing that the in-
fluence of changed conditions accumulates, so that no
effect is produced on a species until it has been exposed
during several generations to continued cultivation or
domestication. Universal experience shows us that when
new flowers are first introduced into our gardens they do
not vary ; but ultimately all, with the rarest exceptions,
vary to a greater or less extent. In a few cases the re-
quisite number of generations, as well as the successive
steps in the progress of variation, have been recorded, as
in the often-quoted instance of the Dahlia.24 After sev-
eral years' culture the Zinnia has only lately (1860) begun
to vary in any great degree. " In the first seven or eight
" years of high cultivation the Swan River daisy (Brachy-
" come iberidifolia) kept to its original colour ; it then
"varied into lilac and purple and other minor shades."25
Analogous facts have been recorded with the Scotch rose.
In discussing the variability of plants several experienced
horticulturists have spoken to the same general effect.

23 ' Die Getreidearten, 1S43, s. 66, b. ii. s. 119.

116,117. 25 'Journal of Horticulture, 1S61, p.

24 Sabiae, in ' Hort. Transact.,' vol. iii. 112; on Zinnia, 'Gardener's Chronicle,'
p. 225; Bronn, ' Gescbichte der Natur,' 1S60, p. 852.

316 CAUSES OF VAKIABILITY. Chap. XXII.

Mr. Salter26 remarks, "Every one knows that the chief
"difficulty is in breaking through the original form and
" colour of the species, and every one will be on the look-
" out for any natural sport, either from seed or branch ;
" that being once obtained, however trifling the change
"may be, the result depends upon himself." M. de
Jonghe, who has had so much success in raising new va-
rieties of pears and strawberries,27 remarks with respect
to the former, "There is another principle, namel)'-, that
" the more a type has entered into a state of variation,
" the greater is its tendency to continue doing so ; and the
" more it has varied from the original type, the more it
"is disposed to vary still farther." We have, indeed,
already discussed this latter point when treating of the
power which man possesses, through selection, of continu-
ally augmenting in the same direction each modification ;
for this power depends on continued variability of the
same general kind. The most celebrated horticulturist
in France, namely, Vilmorin,28 even maintains that, when
any particular variation is desired, the first step is to get
the plant to vary in any manner whatever, and to go on
selecting the most variable individuals, even though they
vary in the wrong direction ; for the fixed character of
the species being once broken, the desired variation will
sooner or later appear.

As nearly all our animals were domesticated at an ex-
tremely remote epoch, we cannot, of course, say whe-
ther they varied quickly or slowly when first subjected
to new conditions. But Dr. Bachman29 states that he
has seen turkeys raised from the eggs of the wild species
lose their metallic tints and become spotted with white
in the third generation. Mr. Yarrell many years ago

26 ' The Chrysanthemum, its History, 28 Quoted by Verlot, ' Des Varietes,'

&c.,' 1S65, p. 3. &c., 1S65, p. 28.

2T 'Gardener's Chron.,' 1855, p. 54; 29 'Examination of the Characteris-

' Journal of Horticulture,' May 9, 1865, tics of Genera and Species :' Charleston,

p. 363. 1855, p. 14.

Chap. XXII. CAUSES OF VARIABILITY. 317

informed me that the wild ducks bred on the ponds in St.
James's Park, which had never been crossed, as it is be-
lieved, with domestic ducks, lost their true plumage after
a few generations. An excellent observer,30 who has often
reared birds from the eggs of the wild duck, and who
took precautions that there should be no crossing with
domestic breeds, has given, as previously stated, full de-
tails on the changes which they gradually undergo. He
found that he could not breed these wild ducks true for
more than five or six generations, "as they then proved
" so much less beautiful. The wdiite collar round the
"neck of the mallard became much broader and more
"irregular, and white feathers appeared in the ducklings'
" wings." They increased also in size of body ; their legs
became less fine, and they lost their elegant carriage.
Fresh eggs Ave re then procured from wild birds ; but
again the same result followed. In these cases of the
duck and turkey we see that animals, like plants, do not
depart from their primitive type until they have been
subjected during several generations to domestication.
On the other hand, Mr. Yarrell informed me that the
Australian dingos, bred in the Zoological Gardens, almost
invariably produced in the first generation puppies mark-
ed with Avhite and other colors; but these introduced
dingos had probably been procured from the natives,
avIio keep them in a semi-domesticated state. It is cer-
tainly a remarkable fact that changed conditions should
at first produce, as far as we can see, absolutely no effect ;
but that they should subsequently cause the character of
the species to change. In the chapter on pangenesis I
shall attempt to throAV a little light on this fact.

Returning noAV to the causes Avhich are supposed to
induce variability. Some authors 3l believe that close in-

30 Mr. Hewitt, 'Journal of Hort.,'lS63, 97,125. In conversation I have found
p. 89. t«-o or three naturalists of the same opi-

81 Devay, ' Manages Consanguins,' pp. nion.

318 CAUSES OF VARIABILITY. Chap. XXII.

terbreeding gives this tendency, and leads to the produc-
tion of monstrosities. In the seventeenth chapter some
few facts were advanced, showing that monstrosities are,
as it appears, occasionally thus caused ; and there can be
no doubt that close interbreeding induces lessened fer-
tility and a weakened constitution ; hence it may lead to
variability : but I have not sufficient evidence on this
head. On the other hand, close interbreeding, if not cai*-
ried to an injurious extreme, far from causing variability,
tends to fix the character of each breed.

It was formerly a common belief, still held by some
persons, that the imagination of the mother affects the
child in the womb.32 This view is evidently not appli-
cable to the lower animals, which lay unimpregnated
eggs, or to plants. Dr. William Hunter, in the last cen-
tury, told my father that during many years every woman
in a large London Lying-in Hospital was asked before
her confinement whether anything had specially affected
her mind, and the answer was written down ; and it so
happened that in no one instance could a coincidence be
detected between the woman's answer and any abnormal
structure ; but when she knew the nature of the struc-
ture, she frequently suggested some fresh cause. The
belief in the power of the mother's imagination may per-
haps have arisen from the children of a second marriage
resembling the previous father, as certainly sometimes
occurs, in accordance with the facts given in the eleventh
chapter.

Crossing as a Cause of Variability. — In an early part
of this chapter it was stated that Pallas 33 and a few other
naturalists maintain that variability is wholly due to cross-
ing. If this means that new characters never sponta-
neously appear in our domestic races, but that they are all

32 Miiller has conclusively argued 83 ' Act. Acad. St. Petersburg,1 1780,

against this belief, 'Elements of Phys.,' part ii., p. 84, <fcc.
Eng. translat., vol. ii., 1S42, p. 1405.

Cuap. xxii. CAUSES OF VARIABILITY. 319

directly derived from certain aboriginal species, the doc-
trine is little less than absurd ; for it implies that animals
like Italian greyhounds, pug-dogs, bull-dogs, pouter and
fan tail pigeons, &c, were able to exist in a state of na-
ture. But the doctrine may mean something -widely dif-
ferent, namely, that the crossing of distinct species is the
sole cause of the first appearance of new characters, and
that without this aid man could not have formed his va-
rious breeds. As, however, new characters have appeared
in certain cases by bud- variation, we may conclude with
certainty that crossing is not necessary for variability.
It is, moreover, almost certain that the breeds of various
animals, such as the rabbit, pigeon, duck, &c, and the
varieties of several plants, are the modified descendants
of a single wild species. Nevertheless, it is probable
that the crossing of two forms, when one or both have
long been domesticated or cultivated, adds to the varia-
bility of the offspring, independently of the commingling
of the characters derived from the two parent-forms ;
and this implies that new characters actually arise. But
we must not forget the facts advanced in the thirteenth
chapter, which clearly prove that the act of crossing
often leads to the reappearance or reversion of long-lost
characters ; and in most cases it would be impsssible to
distinguish between the reappearance of ancient charac-
ters and the first appearance of new characters. Practi-
cally, whether' new or old, they would be new to the
breed in which they reappeared.

Gartner declares,31 and his experience is of the highest value on
such a point, that, when he crossed native plants which had not
been cultivated, he never once saw in the offspring any new charac-
ter ; hut that from the odd manner in which the characters derived
from the parents were combined, they sometimes appeared as if
new. When, on the other hand, he crossed cultivated plants, he
admits that new characters occasionally appeared, but he is strongly

34 ' Bastarderzeugung,' s. 240, 255, 295.

320 CAUSES OF VARIABILITY. Chap. XXII.

inclined to attribute their appearance to ordinary variability, not in
any way to the cross. An opposite conclusion, however, appears to
me the more probable. According to Kolreuter, hybrids in the
genus Mirabilis vary almost infinitely, and he describes new and
singular characters in the form of the seeds, in the colour of the
anthers, in the cotyledons being of immense size, in new and highly
peculiar odours, in the flowers expanding early in the season, and
in their closing at night. With respect to one lot of these hybrids,
he remarks that they presented characters exactly the reverse of
what might have been expected from their parentage.35

Prof. Lecoq 36 speaks strongly to the same effect in regard to this
same genus, and asserts that many of the hybrids from Mirabilis
jalapa and multiflora might easily be mistaken for distinct species,
and adds that they differed in a greater degree, than the other spe-
cies of the genus, from M. jalapa. Herbert also has described 37 the
offspring from a hybrid Rhododendron as being" as unlike all others
" in foliage, as if they had been a separate species." The common
experience of floriculturists proves that the crossing and recrossing of
distinct but allied plants, such as the species of Petunia, Calceolaria,
Fuchsia, Verbena, &c, induces excessive variability ; hence the ap.
pearance of quite new characters is probable. M. Carriere 38 has
lately discussed this subject : he states that Erythrina cristagalU
had been multiplied by seed for many years, but had not yielded
any varieties : it was then crossed with the allied E. herbacca, and
" the resistance was now overcome, and varieties were produced with
" flowers of extremely different size, form, and colour."

From the general and apparently well-founded belief that the
crossing of distinct species, besides commingling their characters,
adds greatly to their variability, it has probably arisen that some
botanists have gone so far as to maintain 39 that, when a genus, in-
cludes only a single species, this when cultivated never varies. The
proposition made so broadly cannot be admitted ; but it is probably
true that the variability of cultivated monotypic genera is much
less than that of genera including numerous species, and this quite
independently of the effects of crossing. I have stated in my ' Origin
of Species,' and in a future work shall more fully show, that the
species belonging to small genera generally yield a less number of
varieties in a state of nature than those belonging to large genera.

36 ' Nova Acta, St. Petersburg,' 1794, 1S60, p. 1081.

p. 378; 1795, pp. 307, 313, 316 ; 1787, p. S9 This was the opinion of the elder

407. De Candolle, as quoted in ' Die. Class.

34 ' De la Fecondation,' 1S62, p. 311. d'Hist. Nat.,' torn. viii. p. 405. Puvis in

97 ' Amaryllidacese,' 1S37, p. 362. his work, 'De la Degeneration,' 1S37, p.

38 Abstracted in ' Gard. Chronicle,' 37, has discussed this same point.

Chap. XXII. CAUSES OF VARIABILITY. 321

Hence the species of small genera would, it is probable, produce
fewer varieties under cultivation than the already variable species
of larger genera.

Although we have not at present sufficient evidence that the
crossing of species, which have never been cultivated, leads to the
appearance of new characters, this apparently does occur with spe-
cies which have been already rendered in some degree variable
through cultivation. Hence crossing, like any other change in the
conditions of life, seems to be an element, probably a potent one, in
causing variability. But we seldom have the means of distinguishing,
as previously remarked, between the appearance of really new cha-
racters and the reappearance of long-lost characters, evoked through
the act of crossing. I will give an instance of the difficulty in distin-
guishing such cases. The species of Datura may be divided into
two sections, those having white flowers with green stems, and
those having purple flowers with brown stems : now Naudin 40
crossed Datura la'vis and fcrox,.\>oih of which belong to the white
section, and raised from them 205 hybrids. Of these hybrids every
one had brown stems and bore purple flowers ; so that they resem-
bled the species of the other section of the genus, and not their own
two parents. Naudin was so much astonished at this fact, that he
was led carefully to observe both parent-species, and he discovered
that the pure seedlings of D.fero.r, immediately after germination,
had dark purple stems, extending from the young roots up to the
cotyledons, and that this tint remained ever afterwards as a ring
round the base of the stem of the plant when old. Now I have
shown in the thirteenth chapter that the retention or exaggeration
of an early character is so intimately related to reversion, that it
evidently comes under the same principle. Hence probably we
ought to look at the purple flowers and brown stems of these
hybrids, not as new characters due to variability, but as a return to
the former state of some ancient progenitor.

Independently of the appearance of new characters from crossing*
a few words may be added to what has been said in former chap-
ters on the unequal combination and transmission of the characters
proper to the two parent forms. When two species or races are
crossed, the offspring of the first generation are generally uniform,
but subsequently they display an almost infinite diversity of cha-
racter. He who wishes, says Kolreuter," to obtain an endless num-
ber of varieties from hybrids should cross and recross them. There
is also much variability when hybrids or mongrels are reduced or

49 'Comptes Rendus,' Novembre 21, 41 'Nova Acta. St. Petersburg,' 1794,

18W, p. 633. p. 891.

322 CAUSES OF VAKIABILITY. Chap. XXII.

absorbed by repeated crosses with either pure parent-form ; and a
still higher degree of variability when three distinct species, and
most of all when four species, are blended together by successive
crosses. Beyond this point Gartner,42 on whose authority the fore-
going statements are made, never succeeded in effecting a union ;
but Max Wichura 4S united six distinct species of willows into a
single hybrid. • The sex of the parent-species affects in an inexpli-
cable manner the degree of variability of hybrids ; for Gartner 44
repeatedly found that when a hybrid was used as the father, and
either one of the pure parent-species, or a third species, was used
as the mother, the offspring were more variable than when the
same hybrid was used as the mother, and either pure parent or the
same third species as the father : thus seedlings from Dianthus bar-
batus crossed by the hybrid D. cM/ie?isi-barbatus were more variable
than those raised from this latter hybrid fertilised by the pure D.
barbatus. Max Wichura ib insists strongly on an analogous result
with his hybrid willows. Again Gartner 46 asserts that the degree
of variability sometimes differs in hybrids raised from reciprocal
crosses between the same two species ; and here the sole difference
is, that the one species is first used as the father and then as the
mother. On the whole, we see that, independently of the appearance
of new characters, the variability of successive crossed genera-
tions is extremely complex, partly from the offspring partaking
unequally of the characters of the two parent-forms, and more
especially from their unequal tendency to revert to the same cha-
racters or to those of more ancient progenitors.

On the Manner and on the Period of Action of the
Causes which induce Variability. — This is an extremely
obscure subject, and we need here only briefly consider,
firstly, whether inherited variations are caused by the
organisation being directly acted on, or indirectly through
the reproductive system ; and secondly, at what period of
life or growth they are primarily caused. We shall see
in the two following chapters that various agencies, such
as an abundant supply of food, exposure to a different
climate, increased use or disuse of parts, &c, prolonged
during several generations, certainly modify either the

42 ' Bastarderzeugung,' s. 507, 516, 572. 44 ' Bastarderzeugung,' s. 452, 507.

43 ' Die Bastardbefruchtuug,' etc., 1865, 45 ' Die Bastardbefruchtung,' s. 56.
.24. 4e ' Bastarderzeugung,' s. 423.

Cap. xxii. CAUSES OF VARIABILITY. 3*23

whole organisation or certain organs. This direct action
of changed conditions perhaps comes into play much more
frequently than can be proved, and it is at least clear that
in all cases of bud-variation the action cannot have been
through the reproductive system.

With respect to the part which the reproductive system takes in
causing variability, we have seen in the eighteenth chapter that even
slight changes in the conditions of life have a remarkable power in
causing a greater or less degree of sterility. Hence it seems not
improbable that beings generated through a system so easily affected
should themselves be affected, or should fail to inherit, or inherit in
excess, characters proper to their parents. We know that certain
groups of organic beings, but with exceptions in each group, have
their reproductive systems much more easily affected by changed
conditions than other groups ; for instance, carniverous birds more
readily than carniverous animals, and parrots more readily than
pigeons ; and this fact harmonizes- with the apparently capricious
manner and degree in which various groups of animals and plants
vary under domestication.

Kolreuter47 was struck with the parallelism between the exces-
sive variability of hybrids when crossed and recrossed in various
ways, — these hybrids having their reproductive powers more or less
affected, — and the variability of anciently cultivated plants. Max
Wiehura* has gone one step farther, and shows that with many of
our highly cultivated plants, such as the hyacinth, tulip, auricula,
snapdragon, potato, cabbage, &c, which there is no reason to believe
have been hybridized, the anthers contain many irregular pollen-
grains, in the same state as in hybrids. He finds also in certain
wild forms, the same coincidence between the state of the pollen and
a high degree of variability, as in many species of Rubus ; but in B.
ccesius and idaus, which are not highly variable species, the pollen
is sound. It is also notorious that, many cultivated plants, such as
the banana, pine-apple, breadfruit, and others previously mentioned,
have their reproductive organs so seriously affected as to be gene-
rally quite sterile; and when they do yield seed, the seedlings,
judging from the large number of cultivated races which exist,
must be variable in an extreme degree. These facts indicate that
there is some relation between the state of the reproductive organs

47 ' Dritte Fortsetzung,' 4c, 1T66, s. S5. Berkeley on the same subject in ' Jour-
«9 'Die Bastardbefruchtung,' 4c, nal of Royal Hort. Soc.,' 1S66, p. SO.
1565, s. 92: see also the Rev. M. J.

324 CAUSES OF VARIABILITY. Chap. XXII.

and a tendency to variability ; but we must not conclude tliat the
relation is strict. Although many of our highly cultivated plants
may have their pollen in a deteriorated condition, yet, as we have
previously seen, they yield more seed, and our anciently domesticated
animals are more prolific, than the corresponding species in a state
of nature. The peacock is almost the only bird which is believed to
be less fertile under domestication than in its native state, and it
has varied in a remarkably small degree. From these considera-
tions it would seem that changes in the conditions of life lead either
to sterility or to variability, or to both ; and not that sterility induces
variability. On the whole it is probable that any cause affecting
the organs of reproduction would likewise affect their product, —
that is, the offspring thus generated.

The period of life at which the causes that induce variability act,
is another obscure subject, which has been discussed by various
authors.49 In some of the cases, to be given in the following chap-
ter, of modifications from the direct action of changed conditions,
which are inherited, there can be no doubt that the causes have
acted on the mature or nearly mature animal. On the other hand,
monstrosities, which cannot be distinctly separated from lesser vari-
ations, are often caused by the embryo being injured whilst in the
mother's womb or in the egg. Thus I. Geoffroy St. Hilaire 60 asserts
that poor women who work hard during their pregnancy, and the
mothers of illegitimate children troubled in their minds and forced
to conceal their state, are far more liable to give birth to monsters
than women in easy circumstances. The eggs of the fowl when
placed upright or otherwise treated unnaturally frequently produce
monstrous chickens. It would, however, appear that complex mon-
strosities are induced more frequently during a rather late than
during a very early period of embryonic life ; but this may partly
result from some one part, which has been injured during an early
period, affecting by its abnormal growth other parts subsequently
developed ; and this would be less likely to occur with parts in-
jured at a later period.61 When any part or organ becomes mon-
strous through abortion, a rudiment is generally left, and this
likewise indicates that its development had already commenced.

Insects sometimes have their antennae or legs in a monstrous
condition, and yet the larva? from which they are metamorphosed
do not possess either antenna? or legs ; and in these cases, as Quatre-

49 Dr. P. Lucas has given a history of 50 ' Hist, des Anomalies,' torn. ili. p.

opinion on this subject : ' Hered. Nat.,' 499.
1S4T, torn. i. p. 175. 6i idem, torn. iii. pp. 892, 502.

Chap. XXII. CAUSES OF VARIABILITY. 325

fages M believes, we are enabled to see the precise period at which
the normal progress of development has been troubled. But the
nature of the food given to a caterpillar sometimes affects the col-
ours of the moth, without the caterpillar itself being affected ;
therefore it seems possible that other characters in the mature
insect might be indirectly modified through the larvae. There is
no reason to suppose that organs which have been rendered mon-
strous have always been acted on during their development ; the
cause may have acted on the organisation at a much earlier stage.
It is even probable that either the male or female sexual elements,
or both, before their union, may be affected in such a manner as to
lead to modifications in organs developed at a late period of life ;
in nearly the same manner as a child may inherit from his father a
disease which does not appear until old age.

In accordance with the facts above given, which prove that in
many cases a close relation exists between variability and the steril-
ity following from changed conditions, we may conclude that the
exciting cause often acts at the earliest possible period, namely, on
the sexual elements, before impregnation has taken place. That
an affection of the female sexual element may induce variability
we may likewise infer as probable from the occurence of bud-varia-
tions ; for a bud seems to be the analogue of an ovule. But the
male element is apparently much oftener affected by changed con-
ditions, at least in a visible manner, than the female element or
ovule ; and we know from Gartner's and Wichura's statements that
a hybrid used as the father and crossed with a pure species gives a
greater degree of variability to the offspring, than does the same
hybrid when used as the mother. Lastly, it is certain that varia-
bility may be transmitted through either sexual element, whether
or not originally excited in them, for Kolreuter and Gartner M found
that when two species were crossed, if either one was variable, the
offspring were rendered variable.

Summary. — From the facts given in this chapter, we
may conclude that the variability of organic beings
under domestication, although so general, is not an in-
evitable contingent on growth and reproduction, but
results from the conditions to which the parents have
been exposed. Changes of any kind in the conditions

61 See his interesting work, ' Meta- 63' Diitte Fortsetzung,' &c, s. 123;

morphoses de l'Uomme,' &c, 1862, p. ' Bastarderzeugung,' s. 249.
129.

326 CAUSES OF VAEI ABILITY. Chap. XXIL

of life, even extremely slight changes, often suffice to
cause variability. Excess of nutriment is perhaps the
most efficient single exciting cause. Animals and plants
continue to be variable for an immense period after their
first domestication ; but the conditions to which they
are exposed never long remain quite constant. In the
course of time they can be habituated to certain changes,
so as to become less variable ; and it is possible that
when first domesticated they may have been even more va-
riable than at present. There is good evidence that the
power of changed conditions accumulates ; so that two,
three, or more generations must be exposed to new con-
ditions before any effect is visible. The crossing of dis-
tinct forms, which have already become variable, increases
in the offspring the tendency to further variability, by
the unequal commingling of the characters of the two
parents, by the reappearance of long-lost characters,
and by the appearance of absolutely new characters.
Some variations are induced by the direct action of the
surrounding conditions on the whole organisation, or on
certain parts alone, and other variations are induced
indirectly through the reproductive system being affected
in the same manner as is so common with organic be-
ings when removed from their natural conditions. The
causes which induce variability act on the mature or-
ganism, on the embryo, and, as we have good reason to
believe, on both sexual elements before impregnation has
been effected.

Chap. XXIII. ACTION OF CONDITIONS OF LIFE. 327

CHAPTER XXIII.

DIRECT AND DEFINITE ACTION OF THE EXTERNAL
CONDITIONS OF LIFE.

BLIGHT MODIFICATIONS IN PLANTS FROM THE DEFINITE ACTION OF
CHANGED CONDITIONS IN SIZE, COLOUR, CHEMICAL PROPERTIES,
AND IN THE STATE OF THE TISSUES — LOCAL DISEASES — CONSPI-
CUOUS MODIFICATIONS FROM CHANGED CLIMATE OR FOOD, ETC. —
PLUMAGE OF BIRDS AFFECTED BY PECULIAR NUTRIMENT, AND BY
THE INOCULATION OF POISON — LAND-SHELLS — MODIFICATIONS OF

. ORGANIC BEINGS IN A STATE OF NATURE THROUGH THE DEFINITE
ACTION OF EXTERNAL CONDITIONS — COMPARISON OF AMERICAN
AND EUROPEAN TREES — GALLS — EFFECTS OF PARASITIC FUNGI
— CONSIDERATIONS OPPOSED TO THE BELIEF IN THE POTENT IN-
FLUENCE OF CHANGED EXTERNAL CONDITIONS — PARALLEL SE-
RIES OF VARIETIES — AMOUNT OF VARIATION DOES NOT CORRE-
SPOND "WITH THE DEGREE OF CHANGE IN THE CONDITIONS —
BUD- VARIATION — MONSTROSITIES PRODUCED BY UNNATURAL
TREATMENT — SUMMARY.

If Ave ask ourselves why this or that character has been
modified under domestication, we are, in most cases, lost
in utter darkness. Many naturalists, especially of the
French school, attribute every modification to the "monde
ambiant," that is, to changed climate, with all its diver-
sities of heat and cold, dampness and dryness, light and
electricity, to the nature of the soil, and "to varied kinds
and amount of food. By the term definite action, as used
in this chapter, I mean an action of such a nature that', •
when many individuals of the same variety are exposed
during several generations to any change in their physi-
cal conditions of life, all, or nearly all the individuals, are

328 DEFINITE ACTION OF THE Chap. XXIIL

modified in the same manner. A new sub-variety would
thus be produced without the aid of selection.

I do not include under the term of definite action the
effects of habit or of the increased use and disuse of va-
rious organs. Modifications of this nature, no doubt, are
definitely caused by the conditions to which the beings
are subjected; but they depend much less on the nature
of the conditions than on the laAVS of growth ; hence they
are included under a distinct head in the following chap-
ter. We know, however, far too little of the causes and
laws of variation to make a sound classification. The di-
rect action of the conditions of life, whether leading to
definite or indefinite results, is a totally distinct considera-
tion from the effects of natural selection ; for natural se-
lection depends on the survival under various and com-
plex circumstances of the best-fitted individuals, but has
no relation whatever to the primary cause of any modifi-
cation of structure.

I will first give in detail all the facts which I have been
able to collect, rendering it probable that climate, food,
&c, have acted so definitely and powerfully on the organ-
isation of our domesticated productions, that they have
sufficed to form new sub-varieties or races, without the
aid of selection by man or of natural selection. I will
then give the facts and considerations opposed to this
conclusion, and finally we will weigh, as fairly as we can,
the evidence on both sides.

When we reflect that distinct races of almost all our do-
mesticated animals exist in each kingdom of Europe, and
formerly even in each district of England, we are at first
strongly inclined to attribute their origin to the definite
action of the physical conditions of each country ; and
this has been the conclusionof many authors. But we
•should bear in mind that man annually has to choose
which animals shall be preserved for breeding, and which
shall be slaughtered. We have also seen that both me-
thodical and unconscious selection were formerly prac-

Chap. XXIII. CONDITIONS OF LIFE. 329

tised, and are now occasionally practised by the most
barbarous races, to a much greater extent than might
have been anticipated. Hence it is very difficult to judge
how far the difference in conditions between, for in-
stance, the several districts in England, could have suf-
ficed without the aid of selection to modify the breeds
which have been reared in each. It may be argued that,
as numerous wild animals and plants have ranged dur-
ring many ages throughout Great Britain, and still re-
tain the same character, the difference in conditions be-
tween the several districts could not have modified in
so marked a manner the various native races of cattle,
sheep, pigs, and horses. The same difficulty of distin-
guishing between selection and the definite effects of the
conditions of life, is encountered in a still higher degree
Avhen we compare closely allied natural forms, inhabiting
two countries, such as North America and Europe, which
do not differ greatly in climate, nature of soil etc., for in
this case natural selection will inevitably and rigorously
have acted during a long succession of aires.

From the importance of the difficulty just alluded to, it will be
advisable to give as large a body of facts as possible, showing that
extremely Blight differences in treatment, either in different parts
of the same country, or during different seasons, certainly cause an
appreciable effect, at least on varieties which are already in an un-
stable condition. Ornamental flowers are good for this purpose, as
they are highly variable, and are carefully observed. All floricul-
turists are unanimous that certain varieties are affected by very
slight differences in the nature of the artificial compost in which
they are grown, and by the natural soil of the district, and by the
season. Thus, a skilful judge, in writing on Carnations and Pico-
tees,1 asks "where can Admiral Curzon be seen possessing the
"colour, size, and strength which it has in Derbyshire? Where
" can Flora's Garland be found equal to those at Slough ? Where
" do high-coloured flowers revel better than at Woolwich and Bir-
" mingham ? Yet in no two of these districts do the same varieties

1 'Gardener's Chronicle,' 1853, p. 183.

330 DEFINITE ACTION OF THE Chap. XXIII.

" attain an equal degree of excellence, although each may he receiv-
" ing the attention of the most skilful cultivators." The same
writer then recommends every cultivator to keep five different
kinds of soil and manure, " and to endeavour to suit the respective
" appetites of the plants you are dealing Avith, for without such at-
" tention all hope of general success will he vain." So it is with
the Dahlia : 2 the Lady Cooper rarely succeeds near London, but
does admirably in other districts ; the reverse holds good with other
varieties ; and again, there are others which succeed equally well
in various situations. A skilful gardener 3 states that he procured
cuttings of an old and well-known variety (pulchella) of Verbena,
which from having been propagated in a different situation pre-
sented a slightly different shade of colour ; the two varieties were
afterwards multiplied by cuttings, being carefully kept distinct ; but
in the second year they could hardly be distinguished, and in the
third year no one could distinguish them.

The nature of the season has an especial influence on certain va-
rieties of the Dahlia : in 1841 two varieties were pre-eminently
good, and the next year these same two were pre-eminently bad.
A famous amateur 4 asserts that in 1861 many varieties of the Eose
came so untrue in character, " that it was hardly possible to recog-
"nise them, and the thought was not seldom entertained that the
" grower had lost his tally." The same amateur 5 states that in
1862 two-thirds of his Auriculas produced central trusses of flowers,
and these are remarkable from not keeping true ; and he adds that
in some seasons certain varieties of this plant all prove good, and
the next season all prove bad ; whilst exactly the reverse happens
with other varieties. In 1845 the editor of the ' Gardener's Chron-
icle ' 6 remarked how singular it was that this year many Calceola-
rias tended to assume a tubular form. With heartsease 7 the blotch-
ed sorts do not acquire their proper character until hot weather sets
sets in ; whilst other varieties lose their beautiful marks as soon as
this occurs.

Analogous facts have been observed with leaves : Mr. Beaton as-
serts8 that he raised at Shrubland, during six years, twenty thou-
sand seedlings from the Punch Pelargonium, and not one had varie-
gated leaves ; but at Snrbiton, in Surrey, one-third, or even a great-
er proportion, of the seedlings from this same variety were more or

2 Mr. Wildman, ' Floricultural Soc.,' 4 ' Journal of Horticulture,' 1S61, p.24.

Feb. 7, 1S43, reported in ' Gard. Chron.,' 6 Ibid., 1S62, p. S3.

1843, p. 86. 8 ' Gard. Chron.,' 1S45, p. 660.

i Mr. Robson, in ' Journal of Horticul- 7 Ibid., 1S63, p. 628.

ture,' Feb. 13th, 1S60, p. 122. 8 'Journal of Hort.,' 1S61, pp. 64, 809.

Chap. XXIII. CONDITIONS OF LIFE. 331

less variegated. The soil of another district in Surrey has a strong
tendency to cause variegation, as appears from information given
me by Sir F. Pollock. Verlot3 states that the variegated straw-
berry retains its character as long as grown in a dryish soil, but
soon loses it when planted in fresh and humid soil. Mr. Salter,
who is well known for his success in cultivating variegated plants,
informs me that rows of strawberries were planted in his garden in
1859, in the usual way ; and at various distances in one row, several
plants simultaneously became variegated, and what made the case
more extraordinary, all were variegated in precisely the same man-
ner. These plants were removed, but during the three succeeding
years other plants in the same row became variegated, and in no
instance were the plants in any adjoining row affected.

The chemical qualities, odours, and tissues of plants are often
modified by a change which seems to us slight. The Hemlock is
said not to yield conicine in Scotland. The root of the Aconitum
napellus becomes innocuous in frigid climates. The medicinal pro-
perties of the Digitalis are easily affected by culture. The Rhubarb
flourishes in England, but does not produce the medicinal substance
which makes the plant so valuable in Chinese Tartary. As the Pis-
tacia lentiscus grows abundantly in the South of France, the climate
must suit it, but it yields no mastic. The Laurus sassafras in
Europe loses the odour proper to it in North America. 10 Many
similar facts could be given, and they are remarkable because it
.might have been thought that definite chemical compounds would
have been little liable to change either in quality or quantity.

The wood of the American Locust-tree (Robinia) when grown in
England is nearly worthless, as is that of the Oak-tree when grown
at the Cape of Good Hope. u Hemp and flax, as I hear from Dr.
Falconer, flourish and yield plenty of seed on the plains of India,
but their fibres are brittle and useless. Hemp, on the other hand,
fails to produce in England that resinous matter which is so largely
used in India as an intoxicating drug.

The fruit of the Melon is greatly influenced by slight differences
in culture and climate. Hence it is generally a better plan, accord-
ing to Xaudin, to improve an old kind than to introduce a new one
into any locality. The seed of the Persian Melon produces near

9 ' Des Varietes,' &c, p. 76. Ferussac, ' Bull, des Sc. Nat.,' 1824, torn.

10 Engel, 'Surles Prnp. Medicates des i p. 60. With respect to the rhubarb,
Plantes,' 1S60, pp. 10, 25. On changes &c, see also 'Gardener's Chronicle,'
in the odours of plants, see Dalibert's 1S49, p. 355; 1862, p. 1123.
Experiments, quoted by Beckman, 'In- " Hooker, 'Flora Indica,' p. 82.
ventlons,' vol. ii. p. 344; and Nees, in

332 DEFINITE ACTION OF THE Chap. XXIIL

Paris fruit inferior to trie poorest market kinds, but at Bordeaux
yields delicious fruit. a Seed is annually brought from Thibet to
Kashmir, a and produces fruit weighing from four to ten pounds,
but plants raised from seed saved in Kashmir next year give fruit
weighing only from two to three pounds. It is well known that
American varieties of the Apple produce in their native land mag-
nificent and brightly-coloured fruit, but in England of poor quality
and a dull colour. In Hungary there are many varieties of the
Kidney -bean, remarkable for the beauty of their seeds, but the Eev.
M. J. Berkeley " found that their beauty could hardly ever be pre-
served in England, and in some cases the colour was greatly chang-
ed. We have seen in the ninth chapter, with respect to wheat,
what a remarkable effect transportal from the North to the South
of France, and reversely, produced on the weight of the grain.

When man can perceive no change in plants or animals
which have been exposed to a neAV climate or to differ-
ent treatment, insects can sometimes perceive a marked
change. The same species of cactus has been carried to
India from Canton, Manilla, Mauritius, and from the hot-
houses of Kew, and there is likewise a so-called native
kind, formerly introduced from South America ; all these
plants are alike in appearance, but the cochineal insect
flourishes only on the native kind, on which it thrives
prodigiously. 15 Humboldt remarks 16 that white men
" born in the torrid zone walk barefoot with impunity in
the same apartment where a European, recently landed,
is exposed to the attacks of the Pulex penetrans?" This
insect, the too well-known chigoe, must therefore be able
to distinguish what the most delicate chemical analysis
fails to distinguish, namely, a difference between the
blood or tissues of a European and those of a white man
born in the country. But the discernment of the chigoe

12 Naudin, ' Annales des Sc. Nat.,' 4th 15 Royle, 'Productive Resources of
series, Bot., torn. xi. 1S59, p. 81. 'Gar- India,' p. 59.

dener's Chronicle,' 1S59, p. 464. 16 'Personal Narrative,' Eng. trans-

13 Moorcroft's 'Travels,' &c, vol. ii. lat., vol. v. p. 101. This statement has
p. 143. been confirmed by Karsten (' Beitrag zur

14 'Gardener's Chronicle,' 1S61, p. Kenntniss der Rhynchoprion :' Moscow,
1113. 1864, s. 39), and by others.

Chap. XXIII. CONDITIONS OF LIFE. 333

is not so surprising as it at first appears ; for according
to Liebig " the blood of men with different complexions,
though inhabiting the same country, emits a different
odour.

Diseases peculiar to certain localities, heights, or climates, may
be here briefly noticed, as showing the influence of external circum-
stances on the human body. Diseases confined to certain races of
man do not concern us, for the constitution of the race may play the
more important part, and this may have been determined by un-
known causes. The Plica Polonica stands, in this respect, in a
nearly intermediate position ; for it rarely affects Germans, who in-
habit the neighbourhood of the Vistula, where so many Poles are
grievously affected ; and on the other hand, it does not affect Rus-
sians, who are said to belong to the same original stock with the
Poles. 18 The elevation of a district often governs the appearance
of diseases ; in Mexico the yellow fever does not extend above 924
metres ; and in Peru, people are affected with the rcrugas only be-
tween 600 and 1600 metres above the sea ; many other such cases
could be given. A peculiar cutaneous complaint, called the Bouton
d'Alep, affects in Aleppo and some neighbouring districts almost
every native infant, and some few strangers ; and it seems fairly
well established that this singular complaint depends on drinking
certain waters. In the healthy little island of St. Helena the scar-
let-fever is dreaded like the Plague ; analogous facts have been ob-
served in Chili and Mexico. I9 Even in the different departments of
France it is found that the various infirmities which render the
conscript unfit for serving in the army, prevail with remarkable in-
equality, revealing, as Boudin observes, that many of them are en-
demic, which otherwise would never have been suspected. 20 Any
one who will study the distribution of disease will be struck with
surprise at what slight differences in the surrounding circumstances
govern the nature and severity of the complaints by which man is
at least temporarily affected.

The modifications as yet referred to have been ex-
tremely slight, and in most cases have been caused, as
far as we can judge, by equally slight changes in the con-

17 'Organic Chemistry,' Eng. trans- 1S45, p. 434.

lat., 1st edit., p. 369. 20 These statements on disease are

19 Prichard, ' Phys. Hist, of Mankind,' taken from Dr. Boudjn's ' Geographie et

1351, vol. i. p. 16R. de Statistique Medicales,' 1S57, torn. i. p.

19 Darwin, 'Journal of Researches,' xliv. and Hi. ; torn. ii. p. 815.

334 DEFINITE ACTION OF THE Chap. XXIII.

ditions. But can it be safely maintained that such
changed conditions, if acting during a long series of
generations, would not produce a marked effect ? It is
commonly believed that the people of the United States
differ in appearance from the parent Anglo-Saxon race ;
and selection cannot have come into action within so
short a period. A good observer21 states that a general
absence of fat, a thin and elongated neck, stiff and lank
hair, are the chief characteristics. The change in the na-
ture of the hair is supposed to be caused by the dryness
of the atmosphere. If immigration into the United States
were now stopped, who can say that the character of the
whole people would not be greatly modified in the course
of two or three thousand years ?

The direct and definite action of changed conditions, in contradis-
tinction to the accumulation of indefinite variations, seems to me so
important that I will give a large additional hody of miscellaneous
facts. With plants, a considerable change of climate sometimes
produces a conspicuous result.. I have given in detail in the ninth
chapter the most remarkable case known to me, namely, that
in Germany several varieties of maize brought from the hotter
parts of America were transformed in the course of only two or
three generations. Dr. Falconer informs me that he has seen the
English Ribston-pippin apple, a Himalayan oak, Primus and Pyrus,
all assume in the hotter parts of India a fastigate or pyramidal
habit ; and this fact is the more interesting, as a Chinese tropical
species of Pyrus naturally has this habit of growth. Although in
these cases the changed manner of growth seems to have been di-
rectly caused by the great heat, we know that many fastigate trees
have originated in their temperate homes. In the Botanic Gardens
of Ceylon the apple-tree " " sends out numerous runners under
ground, which continually rise into small stems, and form a growth
around the parent-tree." The varieties of the cabbage which pro-
duce heads in Europe fail to do so in certain tropical countries.23
The Rhododendron ciliatum produced at Kew flowers so much
larger and paler-coloured than those which it bears on its native

21 E. Desor, quoted in the ' Anthrop. 22 ' Ceylon,' by Sir J. E. Tennent, vol.

Rev.,' 1863, p. 180. For much confirma- i., 1S59, p. 89.

tory evidence, see Quatrefages, ' Unite 23 Godron, ' De l'Espece,' torn. ii. p.

de l'Espece Humaine,' 1861, p. 131. 52.

Chap. XXIII. . CONDITIONS OF LIFE. 335

Himalayan mountain, that Dr. Hooker24 would hardly have recog-
nised the species by the flowers alone. Many similar facts with
respect to the colour and size of flowers could be given.

The experiments of Vilmorin and Buckman on carrots and pars-
nips prove that abundant nutriment produces a definite and inherit-
able effect on the so-called roots, with scarcely any change in other
parts of the plant. Alum directly iDfluences the colour of the
flowers of the" Hydrangea.25 Dryness seems generally to favour the
hairyness or villosity of plants. Gartner found that hybrid Verbas-
cums became extremely woolly when grown in pots. Mr. Masters,
on the other hand, states that the Opuntia leucotricha "is well
" clothed with beautiful white hairs when grown in a damp heat ;
" but in a dry heat exhibits none of this peculiarity." M Slight va-
riations of many kinds, not worth specifying in detail are retained
only as long as plants are grown in certain soils, of which Sageret 27
gives from his own "experience some instances. Odart, who insists
strongly on the permanence of the varieties of the grape, admits29
that some varieties, when grown under a different climate or treat-
ed differently, vary in an extremely slight degree, as in the tint of
the fruit and in the period of ripening. Some authors have denied
that grafting causes even the slightest difference in the scion ; but
there is sufficient evidence that the fruit is sometimes slightly af-
fected in size and flavour, the leaves in duration, and the flowers in
appearance.29

With animals there can be no doubt, from the facts given in the
first chapter, that European dogs deteriorate in India, not only in
their instincts but in structure ; but the changes which they under-
go are of such a nature, that they may be partly due to reversion to
a primitive form, as in the case of feral animals. In parts of India
the turkey becomes reduced in size, " with the pendulous appendage
over the beak enormously developed." 30 We have seen how soon
the wild duck, when domesticated, loses its true character, from the
effects of abundant or changed food, or from taking little exercise.
From the direct action of a humid climate and poor pasture the

24 'Journal of Horicultural Soc.,' vol. 2' 'Ampelographie,' 1S49, p. 19.

vii., 1852, p. 117. ™ Gartner, 'Bastarderz.,' s. 006, has

25 'Journal of Hort. Soc.,' vol. i. p. collected nearly all recorded facts. An-
160. drew Knight (in ' Transact. Hort. Soc.,'

26 See Lecoq on the Villosity of Plants, vol. ii. p. 1G0) goes so far as to maintain
' Geograph. Bot.,' torn. iii. pp. 287, 291 ; that few varieties are absolutely perma-
Gartner, ' Bastarderz.,' s. 201 ; Mr. Mas- nent in character when propagated by
ters, on the Opuntia, in ' Gard. Chroni- buds or grafts.

cle,' 1846, p. 444. 30 Mr. Blyth, in ' Annals and Mag. of

27 ' Pom. Phys.,' p. 136. Nat. Hist.,' vol. xx., 1847, p. 391.

836 DEFINITE ACTION OF THE Chap. XXIII.

horse rapidly decreases in size in the Falkland Islands. From in-
formation which I have received, this seems likewise to be the case
to a certain extent with sheep in Australia.

Climate definitely influences the hairy covering of animals ; in
the West Indies a great change is produced in the fleece of sheep,
in about three generations. Dr. Falconer states 3I that the Thibet
mastiff and goat, when brought down from the Himalaya to Kash-
mir, lose their fine wool. At Angora not only goats, but shepherd-
dogs and cats, have fine fleecy hair, and Mr. Ainsworth 32 attributes
the thickness of the fleece to the severe winters, and its silky lustre
to the hot summers. Burnes states positively 33 that the Karakool
sheep lose their peculiar black curled fleeces when removed into any
other country. Even within the limits of England, I have been as-
sured that with two breeds of sheep the wool was slighty changed
by the flocks being pastured in different localities.34 It has been as-
serted on good authority 35 that horses kept during several years in
the deep coal-mines of Belgium become covered with velvety hair,
almost like that on the mole. These cases probably stand in close
relation to the natural change of coat in winter and summer. Naked
varieties of several domestic animals have occasionally appeared ;
but there is no reason to believe that this is in any way related to
the nature of the climate to which they have been exposed.36

It appears at first sight probable that the increased size, the ten-
dency to fatten, the early maturity and altered forms of our im-
proved cattle, sheep, and pigs, have directly resulted from their
abundant supply of food. This is the opinion of many competent
j udges, and probably is to a great extent true. But as far as form
is concerned, we must not overlook the equal or more potent influ-
ence of lessened use on the limbs and lungs. We see, moreover, as
far as size is concerned that selection is apparently a more powerful
agent than a large supply of food, for we can thus only account for
the existence, as remarked to me by Mr. Blyth, of the largest and
smallest breeds of sheep in the same country, of Cochin-China fowls
and Bantams, of small Tumbler and large Runt pigeons, all kept
together and supplied with abundant nourishment. Nevertheless

S1 ' Natural History Review,' 1862, p. 35 Isidore Geoffroy St. nilaire, ' Hist.

113. Nat. Gen.,' torn. iii. p. 438.

32 'Journal of Roy. Geographical 3e Azara has made some Rood remarks
Soc.,' vol. ix., 1830, p. 275. on this subject, ' Quadrupedes du Para-

33 ' Travels in Bokhara,' vol. iii. p. guay,' torn. ii. p. 337. See an account
151. of a family of naked mice produced in

34 <S«ealso, on the influence of marshy England, ' Proc. Zoolog. Soc.,' 1S5C, p.
pastures on the wool, Godron,' L'Espece,' 88.

torn. ii. p. 22.

Chap, xxiil CONDITIONS OF LIFE. 66 i

there can be little doubt that our domesticated animals have been
modified, independently of the increased or lessened use of parts, by
the conditions to which they have been subjected, without the aid
of selection. For instance, Prof. Riitinieyer37 shows that the bones
of all domesticated quadrupeds can be distinguished from those of
wild animals by the state of their surface and general appearance.
It is scarcely possible to read Nathusius's excellent ' Vorstudien,' M
and doubt that, with the highly improved races of the pig, abundant
food has produced a conspicuous effect on the general form of the
body, on the breadth of the head and face, and even on the teeth.
Nathusius rests much on the case of a purely bred Berkshire pig,
which when two months old became diseased in its digestive organs,
and was preserved for observation until nineteen months old ; at this
age it had lost several characteristic features of the breed, and had
acquired a long, narrow head, of large size relatively to its small body,
and elongated legs. But in this case and in some others we ought
not to asume that, because certain characters are lost, perhaps
through reversion, under one course of treatment, therefore that
they had been at first directly produced by an opposite course.

In the case of the rabbit, which has become feral on the island of
Porto Santo, we are at first strongly tempted to attribute the whole
change — the greatly reduced size, the altered tints of the fur, and
the loss of certain characteristic marks — to the definite action of the
new conditions to which it has been exposed. But in all such cases
we have to consider in addition the tendency to reversion to pro-
genitors more or less remote, and the natural selection of the finest
shades of difference.

The nature of the food sometimes either definitely induces certain
peculiarities, or stands in some close relation with them. Pallas
long ago asserted that the fat-tailed sheep of Siberia degenerated
and lost their enormous tails when removed from certain saline
pastures ; and . recently Erman 39 states that this occurs with the
Kirgisian sheep when brought to Orenburgh.

It is well known that hemp-seed causes bullfinches and certain
other birds to become black. Mr. Wallace has communicated to me
some much more remarkable facts of the same nature. The natives
of the Amazonian region feed the common green parrot (C/irysotix
festica, Linn.) with the fat of large Siluroid fishes, and the birds thus
treated become beautifully variegated with red and yellow feathers.
In the Malayan archipelago, the natives of Gilolo alter in an analo-

37 ' Die Fauna der Pfahlbauten,' 1S~1, 39 l Travels in Siberia,' Eng. transla*.,

s. 15. vol. L p. 223.

88 ' Schweinschaedel,' 1S64, s. 99.

338 DEFINITE ACTION OF THE Chap. XXIIT.

gous manner the colours of another parrot, namely the Lorius
garrulus, Linn., and thus produce the Lori rajah or King-Lory.
These parrots in the Malay Islands and South America, when fed
by the natives on natural vegetable food, such as rice and plantains,
retain their proper colours. Mr. Wallace has, also, recorded 40 a still
more singular fact. " The Indians (of S. America) have a curious
" art by which they change the colours of the feathers of many birds.
" They pluck out those from the part they wish to paint, and inocu-
" late the fresh wound with the milky secretion from the skin of a
" small toad. The feathers grow of a brilliant yellow colour, and
" on being plucked out, it is said, grow again of the same colour
" without any fresh operation."

Bechstein 4I does not entertain any doubt that seclusion from light
affects, at least temporarily, the colours of cage-birds.

It is well-known that the shells of land-mollusca are affected by
the abundance of lime in different districts. Isidore Geoffroy St.
Hilaire 42 gives the case of Helix lactea, which has recently been
carried from Spain to the South of France and to the Rio Plata, and
in both these countries now presents a distinct appearance, but
whether this has resulted from food or climate is not known. With
respect to the common oyster, Mr. F. Buckland informs me that he
can generally distinguish the shells from different districts ; young
oysters brought from Wales and laid down in beds where " natives "
are indigenous, in the short space of two months begin to assume
the " native " character. M. Costa 43 has recorded a much more re-
markable case of the same nature, namely, that young shells taken
from the shores of England and placed in the Mediterranean, at once
altered their manner of growth and formed prominent diverging
rays, like those on the shells of the proper Mediterranean oyster.
The same individual shell, showing both forms of growth, was ex-
hibited before a society in Paris. Lastly, it is well known that
caterpillars fed on different food sometimes either themselves ac-
quire a different colour or produce moths different in colour.44

40 A. R. Wallace, ' Travels on the confirmed by Mr. Greening, in ' Proc.
Amazon and Rio Negro,' p. 294. of the Northern Entomolog. Soc.,' July

41 ' Naturgesctnchte der Stubenvogel,' 2Sth, 1862. For the effects of food on
1S40, s. 262, 308. caterpillars, see a curious account by

42 ' Hist, Nat, Gen.,' torn. iii. p. 402. M. Michely, in ' Bull, de la Soc. Imp.

43 ' Bull, de la Soc. Imp. d'Acclimat.,' d'Acclimat.,' torn. viii. p. 563. For
torn. viii. p. 351. analogous fracts from Dahlbom on Hy-

44 See an account of Mr. Gregson's menoptera, see Westwood's ' Modern
experiments on the Abraxvs grossu- Class, of Insects,' vol. ii. p. 98. See also
lariata, ' Proc. Entomolog. Soc.,' Jan. Dr. L. Moller, ' Die Abhangigkeit der
6th, 1862 : these experiments have been Insecten,' 1867, s. 70.

Chap. XXIII. CONDITIONS OF LIFE. 339

It would be travelling beyond my proper limits here to discuss
how far organic beings in a state of nature are definitely modified
by changed conditions. In my ' Origin of Species ' I have given a
brief abstract of the facts bearing on this point, and have shown the
influence of light on the colours of birds, and of residence near the
sea on the lurid tints of insects, and on the succulency of plants.
Mr. Herbert Spencer 45 has recently discussed with much ability this
whole subject on broad and general grounds. He argues, for in-
stance, that with all animals the external and internal tissues are
differently acted on by the surrounding conditions, and they invaria-
bly differ in intimate structure. So again the upper and lower sur-
faces of true leaves, as well as of stems and petioles, when these
assume the function and occupy the position of leaves, are different-
ly circumstanced with respect to light, &c, and apparently in conse-
quence differ in structure. But, as Mr. Herbert Spencer admits, it
is most difficult in all such cases to distinguish between the effects
of the definite action of physical conditions and the accumulation
through natural selection of inherited variations which are service-
able to the organism, and which have arisen independently of the
definite action of these conditions.

Although we are not here concerned with organic
beings in a state of nature, vet I may call attention to one
case. Mi". Meehan,46 in a remarkable paper, compares
twenty-nine kinds of American trees, belonging to vari-
ous orders, with their nearest European allies, all grown
in close proximity in the same garden and under as nearly
as possible the same conditions. In the American species
Mr. Meehan finds, with the rarest exceptions, that the
leaves fall earlier in the season, and assume before falling
a brighter tint ; that they are less deeply toothed or ser-
rated; that the buds are smaller; that the trees are more
diffuse in growth and have fewer branchlets ; and, lastly,
that the seeds are smaller — all in comparison with the
corresponding European species. Now, considering that
these trees belong to distinct orders, it is out of the ques-

** ' The Principles of Biology,' vol. ii. make so much use of it as I should other-

1866. The present chapters were written wise probably have done,

before I had read Mr. Herbert Spencer's 4" ' Proc. Acad. Nat. Soc. of Philadel'

work, so that I. have not been able to pbia,' Jan. 2Sth, 1862.

340 DEFINITE ACTION OF THE Chap. XXIII.

tion that the peculiarities just specified should have been
inherited in the one continent from one progenitor, and
in the other from another progenitor ; and considering
that the trees inhabit widely different stations, these
peculiarities can hardly be supposed to be of any special
service to the two series in the Old and New Worlds ;
therefore these peculiarities cannot have been naturally
selected. Hence we are led to infer that they have been
definitely caused by the long-continued action of the dif-
ferent climate of the two continents on the trees.

Galls. — Another class of facts, not relating to cultivated
plants, deserves attention. I allude to the production of
galls. Every one knows the curious, bright-red, hairy
productions on the wild rose-tree, and the various differ-
ent galls produced by the oak. Some of the latter re-
semble fruit, with one face as rosy as the rosiest apple.
These bright colours can be of no service either to the
gall-forming insect or to the tree, and probably are the
direct result of the action of the light, in the same man-
ner as the apples of Nova Scotia or Canada are brighter
coloured than English apples. The strongest upholder
of the doctrine that organic beings are created beautiful
to please mankind would not, I presume, extend this view
to galls. According to Osten Sacken's latest revision,
no less than fifty-eight kinds of galls are produced on the
several species of oak, by Cynips with its sub-genera ;
and Mr. B. D. Walsh47 states that he can add many
others to the list. One American species of willow, the
iSalix humilis, bears ten distinct kinds of galls. The
leaves which spring from the galls of various English
willows differ completely in shape from the natural
leaves. The young shoots of junipers and firs, when
punctured by certain insects, yield monstrous growths
like flowers and cones ; and the flowers of some plants

47 See Mr. B. D. Walsh's excellent delphia,' Dec. 186G, p. 284. With re-
papers in ' Proc. Entomolog. Soc. Phila- spect to the willow, see idem, 1864, p. 546.

Cuap. xxiii. CONDITIONS OF LIFE. 341

become from the same cause "wholly changed in appear-
ance. Galls are produced in every quarter of the world ;
of several sent to me by Mr. Thwaites from Ceylon, some
•were as symmetrical as a composite flower when in bud,
others smooth and spherical like a berry ; some protected
by long spines, others clothed with yellow wool formed
of long cellular hairs, others with regularly tufted hairs.
In some galls the internal structure is simple, but in
others it is highly complex ; thus M. Lucaze-Duthiers 48
has figured in the common ink-gall no less than seven
concentric layers, composed of distinct tissue, namely, the
epidermic, sub-epidermic, spongy, intermediate, and the
hard protective layer formed of curiously thickened
woody cells, and, lastly, the central mass abounding with
starch-granules on which the larvae feed.

Galls are produced by insects of various orders, but the
greater number by species of Cynips. It is impossible to
read M. Lucaze-Duthiers discussion and doubt that the
poisonous secretion of the insect causes the growth of
the gall, and every one knows how virulent is the poison
secreted by wasps and bees, which belong to the same
order with Cynips. Galls grow with extraordinary ra-
pidity, and it is said that they attain their full size in a
few days ;49 it is certain that they a.re almost completely
developed before the larvae are hatched. Considering
that many gall-insects are extremely small, the drop of
secreted poison must be excessively minute ; it probably
acts on one or two cells alone, which, being abnormally
stimulated, rapidly increase by a process of self-division.
Galls, as Mr. Walsh 60 remarks, afford good, constant, and
definite characters, each kind keeping as true to form as
does any independent organic being. This fact becomes
etill more remarkable when we hear that, for instance,

48 See his admirable nistoire de3 1818, vol. 5. p. 450 ; Lucaze-Duthiers,

Galle3, in ' Annal. des Sc. Nat. Bot.,' idem, p. 284.

8rd series, torn, xix., 1853, p. 27-3. 60'Proc. Entomolog. Soc. Philadel-

<8 Kirby and Spence's ' Entomology,1 puia,' 1864, p. 553.

342 DEFINITE ACTION OF THE Chap. XXIII.

seven out of the ten different kinds of galls produced on
Salix humilis are formed by gall-gnats (Cecklomyicbx)
which, " though essentially distinct species, yet resemble
"one another so closely that in almost all cases it is diffi-
" cult, and in some cases impossible, to distinguish the
" full-grown insects one from the other." 51 For in ac-
cordance with a wide-spread analogy we may safely infer
that the poison secreted by insects so closely allied would
not differ much in nature ; yet this slight difference is
sufficient to induce widely different results. In some few
cases the same species of gall-gnat produces on distinct
species of willows galls which cannot be distinguished ;
the Cynips fecundatrix, also, has been known to produce
on the Turkish oak, to which it is not properly attached,
exactly the same kind of gall as on the European oak."
These latter facts apparently prove that the nature of the
poison is a much more powerful agent in determining the
form of the gall than the specific character of the tree
which is acted on.

As the poisonous secretion of insects belonging to vari-
ous orders has the special power of affecting the growth
of various plants ; — as a slight difference in the nature of
the poison suffices to produce widely different results ; —
and lastly, as we know that the chemical compounds se-
creted by plants are eminently liable to be modified by
changed conditions of life, we may believe it possible that
various parts of a plant might be modified through the
agency of its own altered secretions. Compare, for in-
stance, the mossy and viscid calyx of a moss-rose, which
suddenly appears through bud-variation on a Provence-
rose, with the gall of red moss growing from the inocu-
lated leaf of a wild rose, with each filament symmetri-
cally branched like a microscopical spruce-fir, bearing a
glandular tip and secreting odoriferous gummy matter."

»i Mr. B. D. Walsh, idem, p. 633 ; and 411, 495; and Dec. 1S66, p. 278. See also
Dec. 1S66, p. 275. Lucaze-Duthiers.

M Mr. B. D. Walsh, idem, 1864, p. 545, M Lucaze-Duthiers, idem, pp. 325, 328

Chap. XXIII. CONDITION'S OF LIFE. 8-13

Or compare, on the one hand, the fruit of the peach, with
its hairy skin, fleshy covering, hard shell and kernel, and
on the other hand one of the more complex galls with its
epidermic, spongy, and woody layers, surrounding tissue
loaded with starch granules. These normal and abnor-
mal structures manifestly present a certain degree of re-
semblance. Or, again, reflect on the cases above given
of parrots which have had their plumage brightly deco-
rated through some change in their blood, caused by hav-
ing been fed on certain fishes, or locally inoculated with
the poison of a toad. I am far from wishing to maintain
that the moss-rose or the hard shell of the peach -stone or
the bright colours of birds are actually due to any chemi-
cal change in the sap or blood ; but these cases of galls
and of parrots are excellently adapted to show us how
powerfully and singularly external agencies may affect
structure. With such facts before us, we need feel no
surprise at the appearance of any modification in any or-
ganic being.

I may, also, here allude to the remarkable effects which parasitic
fungi sometimes produce on plants. . Reissek °4 has described a The-
sium, affected by an CEcidium, which was greatly modified, and as-
sumed some of the characteristic features of certain allied species,
or even genera. Suppose, says Reissek, " the condition originally
" caused by the fungus to become constant in the course of time, the
" plant would, if found growing wild, be considered as a distinct spe-
" cies or even as belonging to a new genus." I quote this remark
to show how profoundly, yet in how natural a manner, this plant
must have been modified by the parasitic fungus.

Facts and Considerations opposed to the belief that the
Conditions of Life act in a potent manner in causing,
definite Modifications of Structure.

I have alluded to the slight differences in species when
naturally living in distinct countries under different con-

64 ' Linnsea,' vol. xvii., 1S43 ; quoted by Dr. M. T. Masters, Royal Institution, March
lOtb, I860.

344 DEFINITE ACTION OF THE Chap. XXIII.

ditions; and such differences we feel at first inclined,
probably to a limited extent with justice, to attribute to
the definite action of the surrounding conditions. But it
must be borne in mind that there are a far greater num-
ber of animals and plants which range widely and have
been exposed to great diversities of conditions, yet re-
main nearly uniform in character. Some authors, as
previously remarked, account for the varieties of our
culinary and agricultural plants by the definite action of
the conditions to which they have been exposed in the
different parts of Great Britain; but there are about 200
plants " which are found in every single English county ;
these plants must have been exposed for an immense
period to considerable differences of climate and soil, yet
do not differ. So again, some birds, insects, other ani-
mals, and plants range over large portions of the world,
yet retain the same character.

Notwithstanding the facts previously given on the occurrence of
highly peculiar local diseases and on the strange modifications of
structure in plants caused by the inoculated poison of insects, and
other analogous cases ; still there are a multitude of variations —
such as the modified skull of the niata ox and bulldog, the long
horns of Caffre cattle, the conjoined toes of the solid-hoofed swine,
the immense crest and protuberant skull of Polish fowls, the crop
of the pouter-pigeon, and a host of other such cases — which we can
hardly attribute to the definite action, in the sense before specified,
of the external conditions of life. No doubt in every case there
must have been some exciting cause ; but as we see innumerable
individuals exposed to nearly the same conditions, and one alone is
affected, we may conclude that the constitution of the individual is
of far higher importance than the conditions to which it has been
exposed. It seems, indeed, to be a general rule that conspicuous
variations occur rarely, and in one individual alone out of many
thousands, though all may have been exposed, as far as we can
j udge, to nearly the same conditions. As the most strongly marked
variations graduate insensibly into the most trifling, we are led by
the same train of thought to attribute each slight variation much

68 Hewett C. Watson, ' Cybele Britannica,' vol. i. 1847, p. 11.

Chap. XXIII. CONDITIONS OF LIFE. 345

more to innate differences of constitution, however caused, than to
the definite action of the surrounding conditions.

We are led to the same conclusion by considering the cases,
formerly alluded to, of fowls and pigeons, which have varied and
will no doubt go on varying in directly opposite ways, though kept
daring many generations under nearly the same conditions. Some,
for instance, are born with their beaks, wings, tails, legs, &c, a
little longer, and others with these same parts a little shorter. By
the long-continued selection of such slight individual differences,
which occur in birds kept in the same aviary, widely different races
could certainly be formed; and long-continued selection, impor-
tant as is the result, does nothing but preserve the variations which
appear to us to arise spontaneously.

In these cases we see that domesticated animals vary in an inde-
finite number of particulars, though treated as uniformly as is possi-
ble. On the other hand, there are instances of animals and plants,
which, though exposed to very different conditions, both under
nature and domestication, have varied in nearly the same manner.
Mr. Layard informs me that he has observed amongst the Caffres of
South Africa a dog singularly like an arctic Esquimaux dog. Pi-
geons in India present nearly the same wide diversities of colour as
in Europe ; and I have seen chequered and simply barred pigeons,
and pigeons with blue and white loins, from Sierra Leone, Madeira,
England, and India. New varieties of flowers are continually
raised in different parts of Great Britain, but many of these are
found by the judges at our exhibitions to be almost identical with
old varieties. A vast number of new fruit-trees and culinary vege-
tables have been produced in North America : these differ from
European varieties in the same general manner as the several varie-
ties raised in Europe differ from each other ; and no one has ever
pretended that the climate of America has given to the many
American varieties any general character by which they can be
recognised. Nevertheless, from the facts previously advanced on
the authority of Mr. Meehan with respect to American and Euro-
pean forest-trees, it would be rash to affirm that varieties raised in
the two countries would not in the course of ages assume a distinc-
tive character. Mr. Masters has recorded a striking fact 50 bearing
on this subject : he raised numerous plants of Hybiscus Syriacus
from seed collected in South Carolina and the Holy Land, where the
parent-plants must have been exposed to considerably different con-
ditions ; yet the seedlings from both localities broke into two simi-

58 ' Gardener's Chronicle,' 185T, p. 629.

346 DEFINITE ACTION OF THE Chap. XXIII.

lar strains, one with obtuse leaves and purple or crimson flowers,
and the other with elongated leaves and more or less pink flowers.
We may, also, infer the prepotent influence of the constitution of
the organism over the definite action of the conditions of life, from
the several cases given in the earlier chapters of parallel series of
varieties, — an important subject, hereafter to be more fully discussed.
Sub-varieties of the several kinds of wheat, gourds, peaches, and
other plants, and to a certain limited extent sub-varieties of the
fowl, pigeon, and dog, have been shown either to resemble or to
differ from each other in a closely corresponding and parallel man-
ner. In other cases, a variety of one species resembles a distinct
species ; or the varieties of two distinct species resemble each other.
Although these parallel resemblances no doubt often result from
reversion to the former characters of a common progenitor ; yet in
other cases, when new characters first appear, the resemblance must
be attributed to the inheritance of a similar constitution, and con-
sequently to a tendency to vary in the same manner. We see
something of a similar kind in the same monstrosity appearing
and reappearing many times in the same animal, and, as Dr. Max-
well Masters has remarked to me, in the same plant.

We may at least conclude thus far, that the amount of
modification which animals and plants have undergone
under domestication, does not correspond with the degree
to which they have been subjected to changed circum-
stances. As we know the parentage of domesticated
birds far better than of most quadrupeds, we will glance
through the list. The pigeon has varied in Europe more
than almost any other bird ; yet it is a native species, and
has not been exposed to any extraordinary change of
conditions. The fowl has varied equally, or almost
equally, with the pigeon, and is a native of the hot jun-
gles of India. Neither the peacock, a native of the same
country, nor the guinea-fowl, an inhabitant of the dry
deserts of Africa, has varied at all, or only in colour.
The turkey, from Mexico, has varied but little. The
duck, on the other hand, a native of Europe, has yielded
some well-marked races ; and as this is an aquatic bird,
it must have been subjected to a far more serious change
in its habits than the pigeon or even the fowl, which

Chap. XXIII. ('< >NIMTI< >XS OF LIFE. 3-17

nevertheless have varied in a much higher degree. The
goose, a native of Europe and aquatic like the cluck, has
varied less than any other domesticated bird, except the
peacock.

Bud-variation is, also, important, under our present
point of view. In some few cases, as when all the eyes
or buds on the same tuber of the potato, or all the fruit
on the same plum-tree, or all the flowers on the same
plant, have suddenly varied in the same manner, it
might be argued that the variation had been definitely
caused by some change in the conditions to which
the plants had been exposed ; yet, in other cases, such
an admission is extremely difficult. As new characters
sometimes appear by bud-variation, which do not occur
in the parent species or in any allied species, we may
reject, at least in these cases, the idea that they are due
to reversion. Now it is well worth while to reflect ma-
turely on some striking case of bud-variation, for instance
that of the peach. This tree has been cultivated by the
million in various parts of the world, has been treated
differently, grown on its own roots and grafted on vari-
ous stocks, planted as a standard, against a wall, and
under glass ; yet each bud of each sub-variety keeps true
to its kind. But occasionally, at long intervals of time,
a tree in England, or under the widely-different climate
of Virginia, produces a single* bud, and this yields a
branch which ever afterwards bears nectarines. Nec-
tarines differ, as every one knows, from peaches in their
smoothness, size, and flavour; and the difference is so
great, that some botanists have maintained that they are
specifically distinct. So permanent are the characters
thus suddenly acquired, that a nectarine produced by
bud-variation has propagated itself by seed. To guard
against the supposition that there is some fundamental
distinction between bud and seminal variation, it is well
to bear in mind that nectarines have likewise been pro-
duced from the stone of the peach; and, reversely,

348 DEFINITE ACTION OF THE Chap. XXIIL

peaches from the stone of the nectarine. Now is it
possible to conceive external conditions more closely alike
than those to which the buds on the same tree are ex-
posed ? Yet one bud alone, out of the many thousands
borne by the same tree, has suddenly without any ap-
parent cause produced a nectarine. But the case is even
stronger than this, for the same flower-bud has yielded
a fruit, one-half or one-quarter a nectarine, and the other
half or three-quarters a peach. Again, seven or eight
varieties of the peach have yielded by bud-variation nec-
tarines : the nectarines thus produced, no doubt, differ a
little from each other ; but still they are nectarines. Of
course there must be some cause, internal or external, to
excite the peach-bud to change its nature ; but I cannot
imagine a class of facts better adapted to force on our
minds the conviction that what we call the external con-
ditions of life are quite insignificant in relation to any
particular variation, in comparison with the organisation
or constitution of the being which varies.

It is known from the labours of Geoffroy St. Hilaire,
and recently from those of Dareste and others, that eggs
of the fowl, if shaken, placed upright, perforated, covered
in part with varnish, &c, produce monstrous chickens.
Now these monstrosities may be said to be directly caused
by such unnatural conditions, but the modifications thus
induced are not of a definite nature. An excellent ob-
server, M. Camille Dareste,57 remarks " that the various
*' species of monstrosities are not determined by specific
" causes ; the external agencies which modify the develop-
" ment of the embryo act solely in causing a perturbation —
" a perversion in the normal course of development." He
compares the result to what we see in illness : a sudden
chill, for" instance, affects one individual alone out of

67 ' Memoire sur la Production Artifi- stract is giren of Geoffroy's Experiments

cielle des Monstrosites,' 1S62, pp. S-12; by his son, in his ' Vie, Travaux, <&c.,'

' Recherches sur les. Conditions, «fec, 1S47, p. 290.
chez les Monstres,' 1S63, p. C. An ab-

Chap. XXiil. CONDITIONS OF LIFE. 349

many, causing either a cold, or sore-throat, rheumatism,
or inflammation of the lungs or pleura. Contagious
matter acts in an analogous manner.68 We may take
a still more specific instance : seven pigeons were struck
by rattle-snakes;69 some suffered from convulsions; some
had their blood coagulated, in others it was perfectly
fluid ; some showed ecchymosed spots on the heart, others
on the intestines, &c. ; others again showed no visible
lesion in any organ. It is well known that excess in
drinking causes different diseases in different men ; but
men living under a cold and tropical climate are differ-
ently affected:60 and in this case we see the definite
influence of opposite conditions. The foregoing facts
apparently give us as good an idea as we are likely for a
long time to obtain, how in many cases external condi-
tions act directly, though not definitely, in causing modi-
fications of structure.

Summary. — There can be no doubt, from the facts
given in the early part of this chapter, that extremely
slight changes in the conditions of life sometimes act in a
definite manner on our already variable domesticated pro-
ductions ; and as the action of changed conditions in
causing general or indefinite variability is accumulative,
so it may be with their definite action. Hence it is pos-
sible that great and definite modifications of structure
may result from altered conditions acting during a long
series of generations. In some few instances a marked
effect has been produced quickly on all, or nearly all, the
individuals which have been exposed to some consider-
able change of climate, food, or other circumstance. This
has occurred, and is now occurring, with European men
in the United States, with European dogs in India, with

58 Paget, ' Lectures on Surgical Patho- Mitchell, p. 67.

logy,' 1S53, vol. i. p. 4S3. ,0 Mr. Sedgwick, iu ' British and

69 ' Researches upon the Venom of Foreign Medico-Chirurg. Review,' July

the Rattle-snake,' J.tn. 1SCI, by Dr. 1863, p. ITS

350 DEFINITE ACTION OF THE Chap. XXIII

horses in the Falkland Islands, apparently with various
animals at Angora, with foreign oysters in the Mediter-
ranean, and with maize grown in Europe from tropical
seed. We have seen that the chemical compounds
secreted by plants and the state of their tissues are
readily affected by changed conditions. In some cases a
relation apparently exists between certain characters and
certain conditions, so that if the latter be changed the
character is lost — as with cultivated flowers, with some
few culinary plants, with the fruit of the melon, with fat-
tailed sheep, and other sheep having peculiar fleeces.

The production of galls, and the change of plumage in
parrots when fed on peculiar food or when inoculated by
the poison of a toad, prove to us what great and mysteri-
ous changes in structure and colour may be the definite
result of chemical changes in the nutrient fluids or tis-
sues.

We have also reason to believe that organic beings in
a state of nature may be modified in various definite ways
by the conditions to which they have been long exposed,
as in the case of American trees in comparison with their
representatives in Europe. But in all such cases it is most
difficult to distinguish between the definite results of
changed conditions, and the accumulation through natural
selection of serviceable variations which have arisen
independently of the nature of the conditions. If, for
instance, a plant had to be modified so as to become fitted
to inhabit a humid instead of an arid station, we have no
reason to believe that variations of the right kind would
occur more frequently if the parent-plant inhabited a
station a little more humid than usual. Whether the
station was unusually dry or humid, variations adapting
the plant in a slight degree for directly opposite habits
of life would occasionally arise, as we have reason to
believe from what we know in other cases.

In most, perhaps in all cases, the organisation or
constitution of the being which is acted on, is a much

Chap. XXIII. CONDITIONS OF LIFE. 351

more important element than the nature of the changed
conditions, in determining the nature of the variation.
We have evidence of this in the appearance of nearly
similar modifications under different conditions, and of
different modifications under apparently nearly the same
conditions. We have still better evidence of this in
closely parallel varieties being frequently produced from
distinct races, or even distinct species, and in the fre-
quent recurrence of the same monstrosity in the same
species. We have also seen that the degree to which
domesticated birds have varied, does not stand in any
close relation with the amount of change to which they
have been subjected.

To recur once again to bud-variations. When we re-
flect on the millions of buds which many trees have pro-
duced, before some one bud has varied, we are lost in
wonder what the precise cause of each variation can be.
Let us recall the case given by Andrew Knight of the
forty-year-old tree of the yellow magnum bonum plum,
an old variety which has been propagated by grafts on
various stocks for a very long period throughout Europe
and North America, and on which a single bud suddenly
produced the red magnum bonum. We should also bear
in mind that distinct varieties, and even distinct species,
— as in the case of peaches, nectarines, and apricots, —
of certain roses and camellias, — although separated by a
vast number of generations from any progenitor in com-
mon, and although cultivated under diversified condi-
tions, have yielded by bud-variation closely analogous
varieties. When we reflect on these facts we become
deeply impressed with the conviction that in such cases
the nature of the variation depends but little on the con-
ditions to which the plant has been exposed, and not in
any especial manner on its individual character, but much
more on the general nature or constitution, inherited
from some remote progenitor, of the whole group of al-
lied beings to which the plant belongs. We are thus

352 ACTION OF CONDITIONS OF LIFE. Chap. XXIII.

driven to conclude that in most cases the conditions of
life play a subordinate part in causing any particular
modification; like that which a spark plays, when a mass
of combustibles bursts into flame — the nature of the flame
depending on the combustible matter, and not on the
spark.

No doubt each slight variation must have its efficient
cause ; but it is as hopeless an attempt to discover the
cause of each as to say why a chill or a poison affects
one man differently from another. Even with modifica-
tions resulting from the definite action of the conditions
of life, when all or nearly all the individuals, which have
been similarly exposed, are similarly affected, we can rare-
ly see the precise relation between cause and effect. In
the next chapter it will be shown that the increased use
or disuse of various organs, produces an inherited effect.
It will further be seen that certain variations are bound
together by correlation and other laws. Beyond this
we cannot at present explain either the causes or man-
ner of action of Variation.

Finally, as indefinite and almost illimitable variability
is the usual result of domestication and cultivation, with
the same part or organ varying in different individuals in
different or even in directly opposite ways ; and as the
same variation, if strongly pronounced, usually recurs
only after long intervals of time, any particular variation
would generally be lost by crossing, reversion, and the
accidental destruction of the varying individuals, unless
carefully preserved by man. Hence, although it must
be admitted that new conditions of life do sometimes de-
finitely affect organic beings, it may be doubted whether
well-marked races have often been produced by the di-
rect action of changed conditions without the aid of
selection either by man or nature.

Chap. XXIV. LAWS OF VARIATION. 353

CHAPTER XXIV.

LAWS OF VARIATION — USE AND DISUSE, ETC.

NTSUS FORMATTVUS, OR THE CO-ORDINATING POWER OF THE OR-
GANISATION— ON THE EFFECTS OF THE INCREASED USE AND
DISUSE OF ORGANS — CHANGED HABITS OF LIFE — ACCLIMATI-
SATION "WITH ANIMALS AND PLANTS — TARIOUS METHODS BY
WHICH THIS CAN BE EFFECTED — ARRESTS OF DEVELOPMENT
— RUDIMENTARY ORGANS.

In this and the two following chapters I shall discuss, as
well as the difficulty of the subject permits, the several
laws which govern Variability. These may be grouped
under the effects of use and disuse, including changed
habits and acclimatisation — arrests of development — cor-
related variation — the cohesion of homologous parts —
the variability of multiple parts — compensation of growth
— the position of buds with respect to the axis of the plant
— and lastly, analogous variation. These several subjects
so graduate into each other that their distinction is often
arbitrary.

It may be convenient first briefly to discuss that co-
ordinating and reparative power which is common, in a
higher or lower degree, to all organic beings, and which
was formerly designated by physiologists as the nisus
formativus.

Blumenbach and others ' have insisted that the principle which
permits a Hydra, when cut into fragments, to develop itself into

1 'An Essay on Generation,' Eng. translat., p. 18 ; Paget, ' Lectures on Surgical Patho-
logy,' 1S53, vol. i. p. 209.

354 LAWS OF VARIATION. Chap. XXIV.

two or more perfect animals, is the same with that which causes a
wound in the higher animals to heal by a cicatrice. Such cases as
that of the Hydra are evidently analogous with the spontaneous
division or fissiparous generation of the lowest animals, and like-
wise with the budding of plants. Between these extreme cases
and that of a mere cicatrice we have every gradation. Spallan-
zani,* by cutting off the legs and tail of a Salamander, got in the
course of three months six crops of these members; so that 687
perfect bones were reproduced by one animal during one season.
At whatever point the limb was cut off, the deficient part, and no
more, was exactly reproduced. Even with man, as we have seen in
the twelfth chapter, when treating of polydactylism, the entire limb
whilst in an embryonic state, and supernumerary digits, are occasion-
ally, though imperfectly, reproduced after amputation. When a dis-
eased bone has been removed, a new one sometimes " gradually as-
" sumes the regular form, and all the attachments of muscles,
" ligaments, &c, become as complete as before." 3

This power of regrowth does not, however, always act perfectly :
the reproduced tail of a lizard differs in the forms of the scales from
the normal tail : with certain Orthopterous insects the large hind
legs are reproduced of smaller size : 4 the white cicatrice which in
the higher animals unites the edges of a deep wound is not formed
of perfect skin, for elastic tissue is not produced till long after-
wards.6 " The activity of the nisus formativus," says Blumenbach,
" is in an inverse ratio to the age of the organised body." To this
may' be added that its power is greater in animals the lower they
are in the scale of organisation ; and animals low in the scale cor-
respond with the embryos of higher animals belonging to the same
class. Newport's observations6 afford a good illustration of this
fact, for he found that " myriapods, whose highest development
" scarcely carries them beyond the larva? of perfect insects, can re-
" generate limbs and antennae up to the time of their last moult ;"
and so can the larva? of true insects, but not the mature insect.
Salamanders correspond in development with the tadpoles or larvae
of the tailless Batrachians, and both possess to a large extent the
power of regrowth ; but not so the mature tailless Batrachians.

Absorption often plays an important part in the repairs of inju-
ries. When a bone is broken, and does not unite, the ends are

2 ' An Essay on Animal Reproduction,' vol. i., 1887, p. 145.

Eng. translat., 1769, p. 79. 8 Paget, 'Lectures on Surgical Patho-

3 Carpenter's ' Principles of Comp. logy,' vol. i. p. 239.

Physiology,' 1S54, p. 479. 6 Quoted by Carpenter, ' Comp. Phys.,'

4 Charleswortu's ' Mag. of Nat. Hist.,' p. 479.

Chap. XXIV. EFFECTS OF USE AND DISUSE. 355

absorbed and rounded, so that a false joint is formed ; or if the
ends unite, but overlap, the projecting parts are removed.7 But
absorption comes into action, as Virchow remarks, during the nor-
mal growth of bones ; parts which are solid during youth become
hollowed out for the medullary tissue as tbe bone increases in size.
In trying to understand the many well-adapted cases of regrowth
when aided by absorption, we should remember that most parts of
the organisation, even whilst retaining the same form, undergo
constant renewal ; so that a part which was not renewed would
naturally be liable to complete absorption,

Some cases, usually classed under the so-called nisus formativus,
at first appear to come under a distinct head ; for not only are old
structures reproduced, but structures which appear new are formed.
Thus, after inflammation " false membranes," furnished with blood-
vessels, lymphatics, and nerves, are developed ; or a foetus escapes
from the Fallopian tubes, and falls into tbe abdomen, " nature
" pours out a quantity of plastic lymph, which forms itself into
" organised membrane, richly supplied with blood-vessels," and
the foetus is nourished for a time. In certain cases of hydroce-
phalus the open and dangerous spaces in the skull are filled up
with new bones, which interlock by perfect serrated sutures.8 But
most physiologists, especially on the Continent, have now given up
the belief in plastic lymph or blastema, and Virchow 9 maintains
that every structure, new or old, is formed by the proliferation of
pre-existing cells. On this view false membranes, like cancerous
or other tumours, are merely abnormal developments of normal
growths ; and we can thus understand how it is that they resem-
ble adjoining structures ; for instance, that " false membrane in
" the serous cavities acquires a covering of epithelium exactly like
" that which covers the original serous membrane ; adhesions of
" the iris may become black apparently from the production of
" pigment-cells like those of the uvea." 10

No doubt the power of reparation, though not always quite per-
fect, is an admirable provision, ready for various emergencies, even
for those which occur only at long intervals of time." Yet this
power is not more wonderful than the growth and development of
every single creature, more especially of those which are propagated
by fissi parous generation. This subject has been here noticed, be-

7 Paget, 'Lectures,' Ac, p. 257. Chance, 1860, pp. 27, 441.

8 These cases are given by Blumen- 10 Paget, ' Lectures on Pathology,1 vol.
bach in his ' Essay on Generation,' pp. 1., 1853, p. 857.

52, 54. " Paget, idem. p. 150.
• ' Cellular Pathology,' trans, by Dr.

356 LAWS OF VARIATION. Chap. XXIV.

cause we may infer that, when any part or organ is either greatly
increased in size or wholly suppressed through variation and conti-
nued selection, the co-ordinating power of the organisation will conti-
nually tend to bring all the parts again into harmony with each
other.

On the Effects of the Increased Use and Disuse of
Organs.

It is notorious, and we shall immediately adduce
proofs, that increased use or action strengthens muscles,
glands, sense-organs, &c, and that disuse, on the other
hand, weakens them. I have not met with any clear ex-
planation of this fact in works on Physiology. Mr. Her-
bert Spencer 12 maintains that when muscles are much
used, or when intermittent pressure is applied to the epi-
dermis, an excess of nutritive matter exudes from the
vessels, and that this gives additional development to
the adjoining parts. That an increased flow of blood
towards an organ leads to its greater development is
probable, if not certain. Mr. Paget ia thus accounts for
the long, thick, and dark-coloured hair which occasionally
grows, even in young children, near old-standing inflam-
ed surfaces or fractured bones. When Hunter inserted
the spur of a cock into the comb, which is well supplied
with blood-vessels, it grew in one case in a spiral direc-
tion to a length of six inches, and in another case forward,
like a horn, so that the bird could not touch the ground
with its beak. But whether Mr. Herbert Spencer's view
of the exudation of nutritive matter due to increased move-
ment and pressure, will fully account for the augment-
ed size of bones, ligaments, and especially of internal
glands and nerves, seems doubtful. According to the
interesting observations of M. Sedillot,14 when a portion
of one bone of the lesc or fore-arm of an animal is remov-

12 ' The Principles of Biology,' vol. ii., i. p. 71.

1SG6, chap. 3-5. 14 Coraptes Reodus,' Sept. 26tli, 1SC4,

13 ' Lectures on Pathology,' 1S53, vol. p. 539.

Chap. XXIV. EFFECTS OF USE AND DISUSE. 357

ed and is not replaced by growth, the associated bone
enlarges till it attains a bulk equal to that of the two
bones, of which it has to perform the functions. This is
best exhibited in dogs in which the tibia has been remov-
ed ; the companion bone, which is naturally almost fili-
form and not one-fifth the size of the other, soon acquires
a size equal to or greater than the tibia. Now, it is at
first difficult to believe that increased weight acting on a
straight bone could, by alternately increased and dimin-
ished pressure, cause nutritive matter to exude from the
vessels which permeate the periosteum. Nevertheless, the
observations adduced by Mr. Spencer,15 on the strength-
ening of the bowed bones of rickety children, along their
concave sides, leads to the belief that this is possible.

Mr. H. Spencer has also shown that the ascent of the
sap in trees is aided by the rocking movement caused by
the wind ; and the sap strengthens the trunk " in propor-
" tion to the stress to be borne ; since the more severe
" and the more repeated the strains, the greater must be
" the exudation from the vessels into the surrounding tis-
" sue and the greater the thickening of this tissue by se-
" condary deposits."18 But woody trunks may be formed
of hard tissue without their having been subjected to any
movement, as we see with ivy closely attached to old
walls. In all these cases, it is very difficult to disentan-
gle the effects of long-continued selection from those con-
sequent on the increased action or movement of the part.
Mr. H. Spencer 17 acknowledges this difficulty, and gives
as an instance the spines or thorns of trees, and the
shells of nuts. Here we have extremely hard woody tis-
sue without the possibility of any movement to cause
exudation, and without, as far as we can see, any other
directly exciting cause; and as the hardness of these
parts is of manifest service to the plant, we may look at the

16 'The Principles of Biology,' vol. ii. 16 Idem, vol. ii. p. 2fi9.

p. 243. 17 Idem, vol. ii. p. 278.

358 LAWS OF VARIATION. Chap. XXIV.

result as probably due to the selection of so-called sponta-
neous variations. Every one knows that hard work
thickens the epidermis on the hands ; and when we hear
that with infants long before their birth the epidermis is
thicker on the palms and soles of the feet than on any
other part of the body, as was observed with admiration
by Albinus,18 we are naturally inclined to attribute this
to the inherited effects of long-continued use or pressure.
We are tempted to extend the same view even to the
hoofs of quadrupeds; but who will pretend to determine
how far natural selection may have aided in the formation
of structures of such obvious importance to the animal ?

That use strengthens the muscles may he seen in the limbs of
artisans who follow different trades ; and when a muscle is strength-
ened, the tendons, and the crests of bone to which they are attached,
become enlarged ; and this must likewise be the case with the blood-
vessels and nerves. On the other hand, when a limb is not used, as
by Eastern fanatics, or when the nerve supplying it with nervous
power is effectually destroyed, the muscles wither. So again, when
the eye is destroyed the optic nerve becomes atrophied, sometimes
even in the course of a few months.19 The Proteus is furnished
with branchiae as well as with lungs : and Schreibers 20 found that
when the animal was compelled to live in deep water the branchiae
were developed to thrice their ordinary size, and the lungs were
partially atrophied. When, on the other hand, the animal was com-
pelled to live in shallow water, the lungs became larger and more
vascular, whilst the branchiae disappeared in a more or less com-
plete degree. Such modifications as these are, however, of compa-
tively little value for us, as we do not actually know that they tend
to be inherited.

In many cases there is reason to believe that the lessened x*se of
various organs has affected the corresponding parts in the offspring.
But there is no good evidence that this ever follows in the course
of a single generation. It appears, as in the case of general or in-
definite variability, that several generations must be subjected to

18 Paget, ' Lectures on Pathology,' curious account of the atrophy of the
vol. ii. p. 209. limbs of rabbits after the destruction of

19 Muller's ' Phys.,' Eng. translate, pp. the nerve.

54,791. Prof. Reed has given (' Physio- 20 Quoted by Lecoq. in 'Geograph.

logical and Anat. Researches,' p. 10) a Bot.' torn, i., 1S54, p. 1S2.

Chap. XXIV. EFFECTS OF USE AND DISUSE. 359

changed habits for anjr appreciable result. Our domestic fowls,
ducks, and geese have almost lost, not only in the individual but in
the race, their power of night ; for we do not see a chicken, when
frightened, take flight like a young pheasant. Hence I was led
eaivt'ully to compare the limb-bones of fowls, ducks, pigeons, and
rabbits, with the same bones in the wild parent-species. As the
measurements and weights were fully given in the earlier chap-
ters, I need here ouly recapitulate the results. With domestic pi-
geons, the length of the sternum, the prominence of its crest, the
length of the scapulae and furcula, the length of the wings as mea-
sured from tip to tip of the radius, are all reduced relatively to the
same parts in the wild pigeon. The wing and tail feathers, how-
ever, are increased in length, but this may have as little connection
with the use of the wings or tail, as the lengthened hair on a dog
with the amount of exercise which the breed has habitually taken.
The feet of pigeons, except in the long-beaked races, are reduced in
size. With fowls the crest of the sternum is less prominent, and is
often distorted or monstrous ; the wing-bones have become lighter
relatively to the leg-bones, and are apparently a little shorter in
comparison with those of the parent-form, the Gallus bankiva. With
ducks, the crest of the sternum is affected in the same manner as in
the foregoing cases : the furcula, coracoids, and scapula? are all re-
duced in weight relatively to the whole skeleton : the bones of the
wings are shorter and lighter, and the bones of the legs longer and
heavier, relatively to each other, and relatively to the whole skele-
ton, in comparison with the same bones in the wild-duck. The de-
creased weight and size of the bones, in the foregoing cases, is pro-
bably the indirect result of the reaction of the weakened muscles
on the bones. I failed to compare the feathers of the wings of the
tame and wild duck; but Gloger21 asserts that in the wild duck
the tips of the wing-feathers reach almost to the end of the tail,
whilst in the domestic duck they often hardly reach to its base. He
remarks, also, on the greater thickness of the legs, and says that
the swimming membrane between the toes is reduced ; but I was
not able to detect this latter difference.

With the domesticated rabbit the body, together with the whole
skeleton, is generally larger and heavier than in the wild animal,
and the leg-bones are heavier in due proportion ; but whatever
standard of comparison be taken, neither the leg-bones nor the
scapuhe have increased in length proportionally with the increased
dimensions of the rest of the skeleton. The skull has become in a
marked manner narrower, and, from the measurements of its capa-

21 'Das Abandern der Vogel,' 1S33, s. 74.

360 LAWS OF VARIATION". Chap. XXIV.

city formerly given, we may conclude, that this narrowness results
from the decreased size of the brain, consequent on the mentally
inactive life led by these closely-confined animals.

We have seen in the eighth chapter that silk-moths, which have
been kept during many centuries closely confined, emerge from
their cocoons with their wings distorted, incapable of flight, often
greatly reduced in size, or even, according to Quatrefages, quite ru-
dimentary. This condition of the wings may be largely owing to
the same kind of monstrosity which often affects wild Lepidoptera
when artifically reared from tbe cocoon ; or it may be in part due
to an inherent tendency, which is common to the females of many
Bombycidae, to have their wings in a more or less rudimentary
state ; but part of the effect may probably be attributed to long-
continued disuse.

From the foregoing facts there can be no doubt that
certain parts of the skeleton in our anciently domesticated
animals, have been modified in length and weight by the
effects of decreased or increased use ; but they have not
been modified, as shown in the earlier chapters, in shape
or structure. We must, however, be cautious in extend-
ing this latter conclusion to animals living a free life ; for
these will occasionally be exposed during successive
generations to the severest competition. With wild
animals it would be an advantage in the struggle for life
that every superfluous and useless detail of structure
should be removed or absorbed ; and thus the reduced
bones might ultimately become changed in structure.
With highly- fed domesticated animals, on the other hand,
there is no economy of growth, nor any tendency to the
elimination of trifling and superfluous details of structure.

Turning now to more general observations, Nathusius
has shown that, with the improved races of the pig, the
shortened legs and snout, the form of the articular con-
dyles of the occiput, and the position of the jaws with
the upper canine teeth pi*ojecting in a mcst anomalous
manner in front of the lower canines, may be attributed
to these parts not having been fully exercised. For the
highly-cultivated races do not travel in search of food,

Chap. XXIV. EFFECTS OF USE AND DISUSE. 361

noi' root up the ground with their ringed muzzles. These
modifications of structure, which are all strictly inherited,
characterise several improved breeds, so that they cannot
have been derived from any single domestic or wild
stock." With respect to cattle, Professor Tanner has
remarked that the lungs and liver in the improved breeds
" are found to be considerably reduced in size when com-
" pared with those possessed by animals having perfect
" liberty ;" 23 and the reduction of these organs affects the
general shape of the body. The cause of the reduced
lungs in highly-bred animals which take little exercise is
obvious ; and perhaps the liver may be affected by the nu-
tritious and artificial food on which they largely subsist.

It is well known that, when an artery is tied, the anastomosing
branches, from being forced to transmit more blood, increase in
diameter ; and this increase cannot be accounted for by mere exten-
sion, as their coats gain in strength. Mr. Herbert Spencer "* has
argued that with plants the flow of sap from the point of supply to
the growing part first elongates the cells in this line ; and that the
cells then become confluent, thus forming the ducts ; so that, on
this view, the vessels in plants are formed by the mutual reaction
of the flowing sap^and cellular tissue. Dr. W. Turner has re-
marked,25 with respect to the branches of arteries, and likewise to
a certain extent with nerves, that the great principle of compen-
sation frequently comes into play ; for " when two nerves pass to
"adjacent cutaneous areas, an inverse relation as regards size may
" subsist between them ; a deficiency in one may be supplied by an
" increase in the other, and thus the area of the former may be
" trespassed on by the latter nerve." But how far in these cases the
difference in size in the nerves and arteries is due to original varia-
tion, and how far to increased use or action, is not clear.

In reference to glands, Mr. Paget observes that " when one kidney
" is destroyed the other often becomes much larger, and does double
" work." 26 If we compare the size of the udders and their power
of secretion in cows which have been long domesticated, and in

•- Xathusius, 'Die Racen des Schwei- 24 ' Principles of Biology,' vol. ii. p.263.

nes,' 1 ~ifin, s. 53, 57 ; 'Vorstudien .... 25 'Natural History Review,' vol. iv.,

Behwelneechedel,' 1864, s. 103, 130, 133. Oct. 1SG4, p. G17.

23 ' Journal of Agriculture of Highland 20 ' Lectures on Surgical Pathology,'

Soc.,' July, lbGO, p. 321. 1853, vol. i. p. 27.

362 LAWS OF VARIATION. Chap. XXIV.

certain goats in which the udders nearly touch the ground, with
the size and power of secretion of these organs in wild or half-do-
mesticated animals, the difference is great. A good cow with us
daily yields more than five gallons, or forty pints of milk, whilst a
first-rate animal, kept, for instance, by the Damaras of South Afri-
ca,27 "rarely gives more than two or three pints of milk daily, and
" should her calf be taken from her, she absolutely refuses to give
" any." We may attribute the excellence of our cows, and of cer-
tain goats, partly to the continued selection of the best milking
animals, and partly to the inherited effects of the increased action,
through man's art, of the secreting glands.

It is notorious, as was remarked in the twelfth chapter, that short-
sight is inherited ; and if we compare watchmakers or engravers
with, for instance, sailors, we can hardly doubt that vision contin-
ually directed towards a near object permanently affects the structure
of the eye.

Veterinarians are unanimous that horses become affected with spa-
vins, splints, ringbones, &c, from being shod, and from travelling
on hard roads, and they are almost equally unanimous that these
injuries are transmitted. Formerly horses were not shod in North
Carolina, and it has been asserted that they did not then suffer from
these diseases of the legs and feet.28

Our domesticated quadrupeds are all descended, as far
as is known, from species having erect ears ; yet few kinds
can be named, of which at least one race has not droop-
ing ears. Cats in China, horses in parts of Russia, sheep
in Italy and elsewhere, the guinea-pig in Germany, goats
and cattle in India, rabbits, pigs, and dogs in all long-
civilised countries, have dependent ears. With wild ani-
mals, which constantly use their ears like funnels to catch
every passing sound, and especially to ascertain the direc-
tion whence it comes, there is not, as Mr. Blyth has re-
marked, any species with drooping ears except the ele-
phant. Hence the incapacity to erect the ears is certainly
in some manner the result of domestication ; and this in-
capacity has been attributed by various authors 29 to dis-

27 Andersson, ' Travels in South Afri- S8 Brickell's ' Nat. Hist, of North Caro-

ca,' p. 318. For analogous cases in Soutn lina,' 1739, p. 58.

America, see Aug. St. Hilaire, ' Voyage ae Livingstone, quoted by Touatt on

dans le Province deGoyaz,' torn. i. p. 71. Sheep, p. 142. Hodgson, in ' Journal of

Chap. XXIV. EFFECTS OF USE AND DISUSE. 363

use, for animals protected by man are not compelled ha-
bitually to use their ears. Col. Hamilton Smith.30 states
that in ancient effigies of the dog, " with the exception of
"one Egyptian instance, no sculptwe of the earlier Gre-
"cian era produces representations of hounds with com-
" pletely drooping ears ; those with them half pendulous
" are missing in the most ancient ; and this character in-
" creases, by degrees, in the works of the Roman period."
Godron also has remarked that " the pigs of the ancient
"Egyptians had not their ears enlarged and pendent."31
But it is remarkable that the drooping of the ears, though
probably the effect of disuse, is not accompanied by any
decrease in size; on the contrary, when we remember that
animals so different as fancy rabbits, certain Indian breeds
of the goat, our petted spaniels, bloodhounds, and other
dogs, have enormously elongated ears, it would appear as
if disuse actually caused an increase in length. With
rabbits, the drooping of the much elongated ears has
affected even the structure of the skull.

The tail of no wild animal, as remarked to me by Mr.
Blyth, is curled ; whereas pigs and some races of dogs
have their tails much curled. This deformity, therefore,
appears to be the result of domestication, but whether in
any way connected with the lessened use of the tail is
doubtful.

The epidermis on our hands is easily thickened, as every
one knows, by hard work. In a district of Ceylon the
sheep have " horny callosities that defend their knees, and
" which arise from their habit of kneeling down to crop
" the short herbage, and this distinguishes the Jaffna
" flocks from those of other portions of the island ;" but it
is not stated whether this peculiarity is inherited.32

The mucous membrane which lines the stomach is con-

Asiatic Soc. of Bengal,' vol. xvl., 1847, p. 81 ' De l'Espece,' torn. 1., 1859, p. 367.

1006, &c. Ac. 33 ' Ceylon,' by Sir J. E. Tennent, 1859,

30 'Naturalist Library,' Dogs, vol. ii. vol. ii. p. 531.
1S40, p. 104.

364 LAWS OF VAKIATION. Chap. XXIV.

tinuous with the external skin of the body ; therefore it
is not surprising that its texture should be affected by the
nature of the food consumed, but other and more inter-
esting changes likewise follow. Hunter long ago observed
that the muscular coat of the stomach of a gull (Lams
tridactylus) which had been fed for a year chiefly on grain
was thickened ; and, according to Dr. Edmondston, a
similar change periodically occurs in the Shetland Isl-
ands in the stomach of the Lanes argentatus, which in
the spring frequents the corn-fields and feeds on the seed.
The same careful observer has noticed a great change in
the stomach of a raven which had been long fed on vege-
table food. In the case of an owl (Strix grallaria) simi-
larly treated, Menetries states that the form of the
stomach was changed, the inner coat became leathery, and
the liver increased in size. Whether these modifications
in the digestive organs would in the course of generations
become inherited is not known.33

The increased or diminished length of the intestines,
which apparently results from changed diet, is a more
remarkable case, because it is characteristic of certain
animals in their domesticated condition, and therefore
must be inherited. The complex absorbent system, the
blood-vessels, nerves, and muscles, are necessarily all
modified together with the intestines. According to
Daubenton, the intestines of the domestic cat are one-
third longer than those of the wild cat of Europe ; and
although this species is not the parent-stock of the domes-
tic animal, yet, as Isidore Geoffroy has remarked, the sev-
eral species of cats are so closely allied that the compari-
son is probably a fair one. The increased length appears
to be due to the domestic cat being less strictly carnivorous
in its diet than any wild feline species ; I have seen a

33 For the foregoing statements, see vol. v. p. 550 ; Menetries, as quoted in

Hunter's ' Essays and Observations,' Bronn's ' Geschichte der Natur,' B. ii. s.

1861, vol. ii. p. 329 ; Dr. Edmondston, as 110.
quoted in Macgillivray's ' British Birds,'

Chap. XXIV. CHANGED HABITS OF LIFE. 365

French kitten eating vegetables as readily as meat. Ac-
cording to Cnvier, the intestines of the domesticated pig
exceed greatly in proportionate length those of the wild
boar. In the tame and wild rabbit the change is of an
opposite nature, and probably results from the nutritious
food given to the tame rabbit.34

Changed Habits of Life, independently of the Use or
Disuse of partiexdar Organs. — This subject, as far as the
mental powers of* animals are concerned, so blends into
instinct, on which I shall treat in a future work, that I
will here only remind the reader of the many cases which
occur under domestication, and which are familiar to
every one — for instance the taraeness of our animals — the
pointing or retrieving of dogs — their not attacking the
smaller animals kept by man — and so forth. How much
of these changes ought to be attributed to inherited
habit, and how much to the selection of individuals which
have varied in the desired manner, irrespectively of the
special circumstances under which they have been kept,
can seldom be told. "We have already seen that animals
may be habituated to a changed diet ; but a few addi-
tional instances may here be given.

In the Polynesian Islands and in China the dog is fed
exclusively on vegetable matter, and the taste for this
kind of food is to a certain extent inherited.35 Our sport-
ing dogs will not touch the bones of game birds, whilst
other dogs devour them with greediness. In some parts
of the world sheep have been largely fed on fish. The
domestic hog is fond of barley, the wild boar is said to
disdain it ; and the disdain is partially inherited, for some
young wild pigs bred in captivity showed an aversion
for this grain, whilst others of the same brood relished

84 These statements on the intestines 427, 441.
are taken from Isidore Gcoffroy St. 35 Gilbert White, 'Nat. Hist. Sel-

Hilaire, ' Uist. Nat. Gen.,' torn. iii. pp. bourne,' 1S25, vol. ii. p. 121.

366 LAWS OF VARIATION. Chap. XXIV.

it.36 One of my relations bred some young pigs from a
Chinese sow by a wild Alpine boar ; they lived free in
the park, and were so tame that they came to the house
to be fed ; but they would not touch swill, which was de-
voured by the other pigs. An animal when once accus-
tomed to an unnatural diet, which can generally be ef-
fected only during youth, dislikes its pi'oper food, as
Spallanzani found to be the case with a pigeon which
had been long fed on meat. Individuals of the same spe-
cies take to new food with different degrees of readiness ;
one horse, it is stated, soon learned to eat meat, whilst
another would have perished from hunger rather than
have partaken of it."

The caterpillars of the Bornbyx hesperus feed in a state
of nature on the leaves of the Cafe diable, but, after
having been reared on the Ailanthus, they would not
touch the Cafe diable, and actually died of hunger.'8

It has been found possible to accustom marine fish to
live in fresh water ; but as such changes in fish, and other
marine animals, have been chiefly observed in a state of
nature, they do not properly belong to our present sub-
ject. The period of gestation and of maturity, as shown
in the earlier chapters, — the season and the frequency of
the act of breeding, — have all been greatly modified under
domestication. With the Egyptian goose ihe rate of
change in the season has been recorded.39 The wild
drake pairs with one female, the domestic drake is poly-
gamous. Certain breeds of fowls have lost the habit of
incubation. The paces of the horse, and the manner of
flight in certain breeds of the pigeon, have been modified,
and are inherited. The voice differs much in certain
fowls and pigeons. Some breeds are clamorous and others

ss Burdach, 'Traite de Phys.,' torn. ii. Animaux Dom.,' 1854, torn. i. p. 426.

p. 267, as quoted by Dr. P. Lucas, S8 M. Michely de Cayenne, in ' Bull.

4 L'Hered. Nat.,' torn. 1. p. 388. Soc. d'Acclimat,' torn, viii., 1861, p. 563.

37 This and several other cases are 39 Quatrefages, ' Unite de l'Espece

given by Colin, ' Physiologie Comp. des Huinaine,' 1861, p. 79.

Chap, xxiv ACCLIMATISATION. 307

silent, as in the Call and common duck, or in the Spitz
and pointer dog. Every one knows how dogs differ from
each other in their manner of hunting, and in their ardour
after different kinds of game or vermin.

With plants the period of vegetation is easily changed
and is inherited, as in the case of summer and winter
wheat, barley, and vetches ; but to this subject we shall
immediately return under acclimatisation. Annual plants
sometimes become perennial under a new climate, as I
hear from Dr. Hooker is the case with the stock and mig-
nonette iu Tasmania. On the other hand, perennials
sometimes become annuals, as with the Ricinus in Eng-
land, and as, according to Captain Mangles, with many
varieties of the heartsease. Von Berg 40 raised from seed
of Jlirbascum jihoenicium, which is usually a biennial, both
annual and perennial varieties. Some deciduous bushes
become evergreen in hot countries.41 Rice requires much
water, but there is one variety in India which can be
grown without irrigation.43 Certain varieties of the oat
and of our other cereals are best fitted for certain soils.43
Endless similar facts could be given in the animal and
vegetable kingdoms. They are noticed here because they
illustrate analogous differences in closely allied natural
species, and because such changed habits of life, whether
due to use and disuse, or to the direct action of external
conditions, or to so-called spontaneous variation, would
be apt to lead to modifications of structure.

Acclimatisation. — From the previous remarks we are
naturally led to the much disputed subject of acclimati-
sation. There are two distinct questions : Do varieties
dt^eended from the same species differ in their power of
living under different climates ? And secondly, if they

40 ' Flora,' 1S35, B ii. p. 504. of the Himalaya,' p. 19.

41 Alph. De Candolle, ' Geograph. A3 'Gardener's Chronicle,' 1350, pp.
Dot.,' torn. ii. p. 107^. 204, 219.

42 Royle, ' Illustrations of the Botany

3(38 LAWS OF VARIATION. Chap. XXIV.

so differ, how have they become thus adapted? "We
have seen that European dogs do not succeed well in
India, and it is asserted,44 that no one has succeeded in
there keeping the Newfoundland long alive; but then
it may be argued, probably with truth, that these north-
ern breeds are specifically distinct from the native dogs
which flourish in India. The same remark may be made
with respect to different breeds of sheep, of which, ac-
cording to Youatt,46 not one brought "from a torrid
" climate lasts out the second year," in the Zoological
Gardens. But sheep are capable of some degree of ac-
climatisation, for Merino sheep bred at the Cape of Good
Hope have been found far better adapted for India than
those imported from England.46 It is almost certain that
the breeds of the fowl are descended from the same
species ; but the Spanish breed, Avhich there is good rea-
son to believe originated near the Mediterranean,47 though
so fine and vigorous in England, suffers more from frost
than any other bi-eed. The Arrindy silk-moth introduced
from Bengal, and the Ailanthus moth from the temperate
province of Shan Tung, in China, belong to the same
species, as we may infer from their identity in the cater-
pillar, cocoon, and mature states ;48 yet they differ much
in constitution : the Indian form " will flourish only in
warm latitudes," the other is quite hardy and withstands
cold and rain.

Plants are more strictly adapted to climate than are animals.
The latter when domesticated withstand such great diversities of
climate, that we find nearly the same species in tropical and tem-
perate countries ; whilst the cultivated plants are widely dissimilar.
Hence a larger field is open for inquiry in regard to the acclimatisa-
tion of plants than of animals. It is no exaggeration to say that with
almost every plant which has long heen cultivated varieties exist,

44 Rev. R. Everest, ' Journal As. SoC. 47 Tegetmeier, ' Poultry Book,' 18C6,
of Bengal,' vol. iii. p. 19. p. 102.

45 Youatt on Sheep, 1838, p. 491. 48 Dr. R. Paterson, in a paper commu-

46 Royle, ' Prod. Resources of India,' nicated to Bot. Soc. of Canada, quoted in
p. 158. the ' Reader,' 1863, Nov. 13th.

Chap. XXIV. ACCLIMATISATION. 369

which are endowed with constitutions fitted for very different cli-
mates ; I will select only a few of the more striking cases, as it
would be tedious to give all. In North America numerous fruit-
trees have been raised, and in horticultural publications, — for in-
stance, in Downing1, — lists are given of the varieties which are best
able to withstand the severe climate of the northern States and
Canada. Many American varieties of the pear, plum, and peach
are excellent in their own country, but until recently hardly one
was known that succeeded in England ; and with apples," not one
succeeds. Though the American varieties can withstand a severer
winter than ours, the summer here is not hot enough. Fruit-trees
have originated in Europe as in America with different constitu-
tions, but they are not here much noticed, as the same nurserymen
do not supply a wide area. The Forelle pear flowers early, and
when the flowers have just set, and this is the critical period, they
have been observed, both in France and England, to withstand with
complete impunity a frost of 18° and even 14° Fahr., which killed
the flowers, whether fully expanded or in bud, of all other kinds of
pears.60 This power in the flower of resisting cold and afterwards
producing fruit does not invariably depend, as we know on. good
authority,51 on general constitutional vigour. In proceeding north-
ward, the number of varieties which are enabled to resist the climate
rapidly decreases, as may be seen in the list of the varieties of the
cherry, apple, and pear, which can be cultivated in the neighbour-
hood of Stockholm.62 Near Moscow, Prince Troubetzkoy planted
for experiment in the open ground several varieties of the pear, but
one alone, the Poire sans Pepins, withstood the cold of winter.63
We thus see that our fruit-trees, like distinct species of the same
genus, certainly differ from each other in their constitutional adap-
tation to different climates.

With the varieties of many plants, the adaptation to climate is
often very close. Thus it has been proved by repeated trials " that
" few if any of the English varieties of wheat are adapted for culti-
vation in Scotland ; " M but the failure in this case is at first only in
the quantity, though ultimately in the quality, of the grain produced.
The Rev. J. M. Berkeley sowed wheat -seed from India, and got
" the most meagre ears," on land which would certainly have yield-

** See remarks by Editor in ' Gard. Chronicle,' 1857, p. 612.

Chronicle,' 1848, p. 5. « Ch. Martius, ' Voyage Bot. C6tes

60 ' Gard. Chronicle,' 1860, p. 938. Sept. de la Norvege,' p. 26.

Remarks by Editor and quotation from 63 ' Journal de l'Acad. ITort. de Gand,'

Decaisne. quoted in ' Gard. Chron.,' 1859, p. 7.

61 J. de Jonghe, of Brussels, in ' Gard. 64 ' Gard. Chronicle,' 1S51, p. 396.

3 TO LAWS OF VAKIATION. Chap. XXIV.

cd a good crop from English wheat.65 In these cases varieties have
been carried from a warmer to a cooler climate ; in the reverse case,
as " when wheat was imported directly from France into the West
" Indian Islands, it produced either wholly barren spikes or fur-
" nished with only two or three miserable seeds, while West Indian
" seed by its side yielded an enormous harvest." 66 Here is another
case of close adaptation to a slightly cooler climate ; a kind of wheat
which in England may be used indifferently either as awinter or
summer variety, when sown under the warmer climate of Grignan,
in France, behaved exactly as if it had been a true winter wheat.67

Botanists believe that all the varieties of maize belong to the
same species ; and we have seen that in North America, in proceed-
ing northward, the varieties cultivated in each zone produce their
flowers and ripen their seed within shorter and shorter periods. So
that the tall, slowly maturing southern varieties do not succeed in
New England, and the New English varieties do not succeed in
Canada. I have not met with any statement that the southern
varieties are actually injured or killed by a degree of cold which the
northern varieties withstand with impunity, though this is probable ;
but the production of early flowering and early seeding varieties
deserves to be considered as one form of acclimatisation. Hence it
has been found possible, according to Kalm, to cultivate maize fur-
ther and further northwards in America. In Europe, also, as we
learn from the evidence given by Alph. De Candolle, the culture of
maize has extended since the end of the last century thirty leagues
north of its former boundary.68 On the authority of the great Lin-
naeus,59 I may quote an analogous case, namely, that in Sweden to-
bacco raised from home-grown seed ripens its seed a month sooner
and is less liable to miscarry than plants raised from foreign seed.

With the Vine, differently from the maize, the line of practical cul-
ture has retreated a little southward since the middle ages ; 60 but
this seems due to commerce, including that of wine, being now
freer or more easy. Nevertheless the fact of the vine not having
spread northward shows that acclimatisation has made no progress
during several centuries. There is, however, a marked difference
in the constitution of the several varieties, — some being hardy,
whilst others hke the muscat of Alexandria, require a very high

66 Idem., 1S62, p. 235. 69 ' Swedish Acts,' Eng. translat.,

66 On the authority of Labat, quoted 173940, voL i. Kalm, in his ' Travels,'
in ' Gard. Chron.,' 1862, p. 235. vol. ii. p. 166, gives an analogous case

67 MM. Edwards and Colin. ' Annal. with cotton-plants raised in New Jersey
des Sc. Nat.,' 2nd series, Bot., torn. v. from Carolina seed.

p. 22. «° De Candolle, ' Geograph. Bot.,' p.

68 ' Geograph. Bot.,' p. 337. 339.

Chap. xxiv. ACCLIMATISATION. 37 1

temperature to come to perfection. According to Labat,61 vines
taken from France to the West Indies succeed with extreme diffi-
culty, whilst those imported from Madeira, or the Canary Islands,
thrive admirably.

Gallesio gives a purious account of the naturalisation of the Orange
in Italy. During many centuries the sweet orange was propagated
exclusively by grafts, and so often suffered from frosts that it re-
quired protection. After the severe frost of 1709, and more espe-
cially after that of 1763, so many trees wer.e destroyed that seedlings
from the sweet orange were raised, and, to the surprise of the in-
habitants, their fruit was found to be sweet. The trees thus raised
were larger, more productive, and hardier than the former kinds ;
and seedlings are now continually raised. Hence Gallesio concludes
that much more was effected for the naturalisation of the orange in
Italy by the accidental production of new kinds during a period of
about sixty years, than had been effected by grafting old varieties
during many ages.62 I may add that Risso 63 describes some Portu-
guese varieties of the orange as extremely sensitive to cold, and as
much tenderer than certain other varieties.

The peach was known to Theophrastus, 322 B.C.64 According to
the authorities quoted by Dr. F. Rolle,65 it was tender when first
introduced into Greece, and even in the island of Rhodes only occa-
sionally bore fruit. If this be correct, the peach, in spreading during
the last two thousand years over the middle parts of Europe, must
have become much hardier. At the present day different varieties
differ much in hardiness ; some French varieties will not succeed in
England ; and near Paris, the Pavie de Bonneuil does not ripen its
fruit till very late, even when grown on a wall ; " it is, therefore,
only fit for a very hot southern climate."68

I will briefly give a few other cases. A variety of Magnolia
grandiflora, raised byM. Roy, withstands cold several degrees lower
than that which any other variety can resist. With camellias there
is much difference in hardiness. One particular variety of Noisette
rose withstood the severe frost of 1860 " untouched and hale amidst
a universal destruction of other Noisettes." In New York the
" Irish yew is quite hardy, but the common yew is liable to be cut
" down." I may add that there are varieties of the sweet potato

61 'Gaul. Chronicle,' 1862, p. 235. ** Alph. De Candolle 'Geograph.

62 Gallesio, ' Teoria della Ripro- Hot.,' p. 882.

duzione Veg.,' 1S16, p. 125; and 65 ' Cb. Darwin's Lehre von der

' Trait! du Citrus,' 1S11, p. 359. Entstebung,' &c, 1862, s. 87.

" ' Essai sur l'Hist. des Orangers,' 6S Decaisne, quoted in ' Gard. Chro-

1*13, p. 20, Ac. nicle,' 1S65, p. 271.

372 LAWS OF VARIATION. Chap. XXIV..

(Convolvulus batatas) which are suited for warmer, as well as for
colder, climates.67

The plants as yet mentioned hare been found capable
of resisting an unusual degree of cold or heat, when
fully grown. The following cases refer to plants whilst
young. In a large bed of young Araucarias of the same
age, growing close together and equally exposed, it was
observed,68 after the unusually severe winter of 1860-61,
that, " in the midst of the dying, numerous individuals
" remained on which the frost had absolutely made no
"kind of impression." Dr. Lindley, after alluding to
this and other similar cases, remarks, " Among the les-
" sons which the late formidable winter has taught us,
" is that, even in their power of resisting cold, indivi-
" duals of the same species of plants are remarkably differ-
" ent." Near Salisbury, there was a sharp frost on the
night of May 24th, 1836, and all the French beans (Pha-
seolus vulgaris) in a bed were killed except about one in
thirty, which completely es.caped.89 On the same day
of the month, but in the year 1 864, there was a severe
frost in Kent, and two rows of scarlet-runners (P. multi-
florus) in my garden, containing 390 plants of the same
age and equally exposed, were all blackened and killed
except about a dozen plants. In an adjoining row of
"Fulmer's dwarf bean" (P. vulgaris)^ one single plant
escaped. A still more severe frost occurred four days
afterwards, and of the dozen. plants which had previously
escaped only three survived ; these were not taller or more
vigorous than the other young plants, but they escaped
completely, with not even the tips of their leaves browned.

6T For the magnolia, see Loudon's ' Gard. Chron.,' 1855, p. 822.

• Gard. Mag., vol. xiii., 1S37, p. 21. For 68 The Editor, ' Gard. Chron.,' 1861,

camellias and roses, see ' Gard. Chron.,' p. 239.

1860, p. 384. For the yew, 'Journal of 69 Loudon's 'Gard. Mag.,' vol. xii.,

Hort.,' March 3rd, 1863, p. 174. For 1836, p. 378.
sweet potatoes, see Col. von Siebold, in

Chap. XXIV. ACCLIMATISATION. 373

It was impossible to behold these three plants, with
their blackened, withered, and dead brethren all round
them, and not see at a glance that they differed widely
in constitutional power of resisting frost.

This work is not the proper place to show that wild
plants of the same species, naturally growing at differ-
ent altitudes or under different latitudes, become to a
certain extent acclimatised, as is proved by the different
behaviour of their seedlings when raised in England. In
my ' Origin of Species ' I have alluded to some cases,
and I could add others. One instance must suffice ; Mr.
Grigor, of Forres,70 states that seedlings of the Scotch
fir (Pinus sylvestris), raised from seed from the Conti-
nent and from the forests of Scotland, differ much.
" The difference is perceptible in one-year-old, and more
" so in two-year-old seedlings ; but the effects of the
" winter on the second year's growth almost uniformly
" make those from the Continent quite brown, and
" so damaged, that by the month of March they are
" quite unsaleable, while the plants from the native Scotch
" pine, under the same treatment, and standing along-
" side, although considerably shorter, are rather stouter
" and quite green, so that the beds of the one can be
" known from the other when seen from the distance of a
" mile." Closely similar facts have been observed with
seedling larches.

Hardy varieties would alone be valued or noticed in Europe;
whilst tender varieties, requiring more warmth, would generally
be neglected; but such occasionally arise. Thus Loudon71 de-
scribes a Cornish variety of the elm which is almost an evergreen,
and of which the sho'bts are often killed by the autumnal frosts,. so
that its timber is of litle value. Horticulturists know that some
varieties are much more tender than others : thus all the varieties
of the broccoli are more tender than cabbages ; but there is much
difference in this respect in the sub-varieties of the broccoli ; the

'0 ' Gardener's Chron.,' 1S65, p. 699.

71 ' Arboretum et Fruticetum,' vol. iiL p. 1376.

374 LAWS OF VARIATION. Chap. XXIV.

pink and purple kinds are a little hardier than the white Cape
broccoli, " but they are not to be depended on after the thermome-
" ter falls below 24° Fahr. :" the Walcheren broccoli is less tender
than the Cape, and there are several varieties which will stand
much severer cold than the Walcheren.12 Cauliflowers seed more
freely in India than cabbages.73 To give one instance with flowers :
eleven plants raised from a hollyhock, called the Queen of the
Wlities,™ were found to be much more tender than various other
seedlings. It may be presumed that all tender varieties would
succeed better under a climate wanner than ours. With fruit-
trees, it is well known that certain varieties, for instance of the
peach, stand forcing in a hot-house better than others ; and this
shows either pliability of organisation or some constitutional differ-
ence. The same individual cherry-tree, when forced, has been
observed during successive years gradually to change its period
of vegetation.75 Few pelargoniums can resist the heat of a stove,
but Alba multiflora will, as a most skilful gardener asserts, " stand
" pine-apple top and bottom heat the whole winter, without look-
" ing any more drawn than if it had stood in a common green-
" house ; and Blanche Fleur seems as if it had been made on
" purpose for growing in winter, like many bulbs, and to rest
" all summer." 76 There can hardly be a doubt that the Alba mul-
tiflora pelargonium must have a widely different constitution from
that of most other varieties of this plant ; it would probably with-
stand even an equatorial climate.

We have seen that according to Labat the vine and wheat require
acclimatisation in order to succeed in the West Indies. Similar facts
have been observed at Madras : "two parcels of mignonette-seed,
" one direct from Europe, the other saved at Bangalore (of which
" the mean temperature is much below that of Madras) were sown
" at the same time ; they both vegetated equally favourably, but
" the former all died off a few days after they appeared above
" ground ; the latter still survive, and are vigorous healthy plants."
So gain, " turnip and carrot seed saved at Hyderabad are found to
" answer better at Madras than seed from Europe or from the Cape
" of Good Hope." 77 Mr. J. Scott, of the Calcutta Botanic Gardens,
informs me that seeds of the sweet-pea {Lathyrus odoratus) imported

72 Mr. Robscm, in ' Journal of Horti- ^ 76 ' Gardener's Chronicle,' 1841, p. 291.
culture,' 1861, p. 23. 76 Mr. Beaton, in ' Cottage Gardener,'

73 Dr. Bonavia, ' Report of the Agri.- March 20th, 1S60, p. 377. Queen Mai)
Hort. Soc. of Oudh,' 1866. will also stand stove heat, see ' Gard.

74 ' Cottage Gardener,' I860, April Chronicle,' 1845, p. 226.

24th, p. 57. 77 ' Gardener's Chronicle,' 1S41, 439.

Chap. XXIV. ACCLIMATISATION. 375

from England produce plants, with thick, rigid stems and small
leaves, which rarely blossom and never yield seed ; plants raised
from French seed blossom sparingly, but all the flowers are sterile ,"
on the other hand, plants raised from sweet-peas grown near Dar-
jeeling in Upper India, but originally derived from England, can
be successfully cultivated on the plains of India ; for they flower
and seed profusely, and their stems are lax and scandent. In some
of the foregoing cases, as Dr. Hooker has remarked to me, the
greater success may perhaps be attributed to the seeds having
been more fully ripened under a more favourable climate ; but this
view can hardly be extended to so many cases, including plants,
which, from being cultivated under a climate hotter than their
native one, become fitted for a still hotter climate. We may there-
fore safely conclude that plants can to a certain extent become
accustomed to a climate either hotter or colder than their own ;
although these latter cases have been more frequently observed.

We will now consider the means by which acclimatisa-
tion may be effected, namely, through the spontaneous
appearance of varieties having a different constitution,
and through the effects of use or habit. In regard to the
first process, there is no evidence that a change in the
constitution of the offspring necessarily stands in any
direct relation with the nature of the climate inhabited
by the parents. On the contrary, it is certain that hardy
and tender varieties of the same species appear in the
same country. New varieties thus spontaneously arising
become fitted to slightly different climates in two diffe-
rent ways ; firstly, they may have the power, either as
seedlings or when full-grown, of resisting intense cold, as
with the Moscow pear, or of resisting intense heat, as with
some kinds of Pelargonium, or the flowers may withstand
severe frost, as with the Forelle pear. Secondly, plants
may become adapted to climates widely different from
their own, from flowering and fruiting either earlier or
later in the season. In both these cases the power of ac-
climatisation by man consists simply in thg selection and
preservation of new varieties. But without any direct in-
tention on his part of securing a hardier variety, acclima-
tisation may be unconsciously effected by merely raising

376 LAWS OF VAKIATION. Chap. XXIV.

tender plants from seed, and by occasionally attempting
their cultivation further and further northwards, as in the
case of maize, the orange, and the peach.

How much influence ought to be attributed to inherited
habit or custom in the acclimatisation of animals and
plants is a much more difficult question. In many cases
natural selection can hardly have failed to have come into
play and complicated the result. It is notorious that
mountain sheep resist severe weather and storms of snow
which would destroy lowland breeds; but then mountain
sheep have been thus exposed from time immemorial, and
all delicate individuals will have been destroyed, and the
hardiest preserved. So with the Arrindy silk-moths of
China and India ; who can tell how far natural selection
may have taken a share in the formation of the two races,
which are now fitted for such widely different climates ?
It seems at first probable that the many fruit-trees, which
are so well fitted for the hot summers and cold winters
of North America, in contrast with their poor success
under our climate, have become adapted through habit ;
but when we reflect on the multitude of seedlings annually
raised in that country, and that none would succeed unless
born with a fitting constitution, it is possible that mere
habit may have done nothing towards their acclimatisa-
tion. On the other hand, when we hear that Merino
sheep, bred during no great number of generations at the
Cape of Good Hope — that some European plants raised
during only a few generations in the cooler parts of India,
withstand the hotter parts of that country much better
than the sheep or seeds imported directly from England,
we must attribute some influence to habit. We are led
to the same conclusion when we hear from Naudin 78 that
the races of melons, squashes, and gourds, which have
long been cultivated in Northern Europe, are compara-
tively more precocious, and need much less heat for ma-

78 Quoted byAsa Gray, in 'Am. Journ. of ScL,' 2nd series, Jan. 1S65, p. 106.

Chap. XXIV. ACCLIMATISATION. 377

taring their fruit, than the varieties of the same specie
recently brought from tropical regions. In the recipro-
cal conversion of summer and winter wheat, barley, and
vetches into each other, habit produces a marked effect in
the course of a very few generations. The same thing ap-
parently occurs with the varieties of maize, which, when
carried from the Southern to the Northern States of
America, or into Germany, soon become accustomed to
their new homes. With vine-plants taken to the West
Indies from Madeira, which are said to succeed better
than plants brought directly from France, we have some
degree of acclimatisation in the individual, independently
of the production of new varieties by seed.

The common experience of agriculturists is of some
value, and they often advise persons to be cautious in
trying in one country the productions of another. The
ancient agricultural writers of China recommend the pre-
servation and cultivation of the varieties peculiar to each
country. During the classical period, Columella wrote,
" Vernaculum pecus peregrino longe praestantius est." 79

I am aware that the attempt to acclimatise either ani-
mals or plants has been called a vain chimsera. No doubt
the attempt in most cases deserves to be thus called, if
made independently of the production of new varieties
endowed with a different constitution. Habit, however
much prolonged, rarely produces any effect on a plant
propagated by buds ; it apparently acts only through
successive seminal generations. The laurel, bay, laures-
tinus, &c, and the Jerusalem artichoke, which are pro-
pagated by cuttings or tubers, are probably now as ten-
der in England as when first introduced ; and this appears
to be the case with the potato, which until recently was
seldom multiplied by seed. With plants propagated by
seed, and with animals, there*will be little or no acclima-

78 For China, see ' Memoire sur les Is quoted by Carlier, in ' Journal de
Cbinois,' torn, xi., 1TSC, p. 60. Columella Physique,' torn, xxiv., 1TS4.

378 LAWS OF VAKIATTON. Chap. XXIV.

tisation unless the hardier individuals are either inten-
tionally or unconsciously preserved. The kidney-bean
has often heen advanced as an instance of a plant which
has not become hardier since its first introduction into
Britain. "We hear, however, on excellent authority,80
that some very fine seed, imported from abroad, produced
plants " which blossomed most profusely, but were nearly
" all but abortive, whilst plants grown alongside from
"English seed podded abundantly;" and this appa-
rently shows some degree of acclimatisation in our Eng-
lish plants. We have also seen that seedlings of the
kidney-bean occasionally appear with a marked power of
resisting frost ; but no one, as far as I can hear, has ever
sej^arated such hardy seedlings, so as to prevent accidental
crossing, and then gathered their seed and repeated the
process year after year. It may, however, be objected
with truth that natural selection ought to have had a
decided effect on the hai'diness of kidney-beans ; for the
tenderest individuals must have been killed during every
severe spring, and the hardier preserved. But it should
be borne in mind that the result of increased hardiness
would simply be that gardeners, who are always anxious
for as early a crop as possible, would sow their seed a few
days earlier than formerly. Now, as the period of sowing
depends much on the soil and elevation of each district,
and varies with the season ; and as new varieties have
often been imported from abroad, can we feel sure that
our kidney-beans are not somewhat hardier ? I have not
been able, by searching old horticultural works, to an-
swer this question satisfactorily.

On the whole, the facts now given show that, though
habit does something towards acclimatisation, yet that
the spontaneous appearance of constitutionally different .
individuals is a far more effective agent. As no single
instance has been recorded, either with animals or plants,

80 Messrs. Hardy and Son, in ' Gard. Chronicle,' 1S56, p. 589.

Chap. XXIV. ARRESTED DEVELOPMENT. 379

of hardier individuals having been long and steadily se-
lected, though such selection is admitted to be indispen-
sable for the improvement of any other character, it is
not surprising that man has done little in the acclimati-
sation of domesticated animals and cultivated plants.
We need not, however, doubt that under nature new
races and new species would become adapted to widely
different climates, by spontaneous variation, aided by
habit, and regulated by natural selection.

Arrests of Development: Rudimentary and Aborted
Organs.

These subjects are here introduced because there is reason to be-
lieve that rudimentary organs are in many cases the result of disuse.
Modifications of structure from arrested development, so great or so
serious as to deserve to be called monstrosities, are of common oc-
currence, but, as they differ much from any normal structure, they
require here only a passing notice. When a part or organ is ar-
rested during its embryonic growth, a rudiment is generally left.
Thus the whole head may be represented by a soft nipple like pro-
jection, and the limbs by mere papillae. These rudiments of linibs
are sometimes inherited, as has been observed in a dog.61

Many lesser anomalies in our domesticated animals appear to be
due to arrested development. What the cause of the arrest may be,
we seldom know, except in the case of direct injury to the embryo
within the egg or womb. That the cause does not generally act at
a very early embryonic period we may infer from the affected organ
seldom being wholly aborted, — a rudiment being generally pre-
served. The external ears are represented by mere vestiges in a
Chinese breed of sheep ; and in another breed, the. tail is reduced
" to a little button, suffocated, in a manner, by fat." 82 In tailless
dogs and cats a stump is left ; but I do not know whether it in-
cludes at an early embryonic age rudiments of all the caudal verte-
bra?. In certain breeds of fowls the comb and wattles are reduced
to rudiments ; in the Cochin-China breed scarcely more than rudi-
ments of spurs exist. With polled Suffolk cattle, " rudiments of

K Isid. Geoffroy St. Hilaire, ' nist. act,' 1775, p. 313.
Nat. des Anomalies,' 1S36, torn. ii. pp. 82 Pallas, quoted by Youatt on Sheep,

210, 223, 224, 395; ' Philosoph. Trans- p. 25.

380 LAWS OF VAKIATIOJST. Chap. XXIV.

" horns can often be felt at an early age ;" 83 and with species in a
state of nature, the relatively greater development of rudimentary
organs at an early period of life is highly characteristic of such or-
gans. With hornless breeds of cattle and sheep, another and singu-
lar kind of rudiment has been observed, namely, minute dangling
horns attached to the skin alone, and which are often shed and grow
again. With hornless goats, according to Desmarest,64 the bony
protuberances which properly support the horns exist as mere rudi-
ments.

With cultivated plants it is far from rare to find the petals, sta-
mens, and pistils represented by rudiments, like those observed in
natural species. So it is with the whole seed in many fruits ; thus
near Astrakhan there is a grape with mere traces of seeds, " so small
" and lying so near the stalk that they are not perceived in eating
" the grape." 85 In certain varieties of the gourd, the tendrils, accord-
ing to Naudin, are represented by the rudiments or by various mon-
strous growths. In the broccoli and cauliflower the greater num-
ber of the flowers are incapable of expansion, and include rudiment-
ary organs. In the Feather hyacinth {Muscari comosum) the upper
and central flowers are brightly coloured but rudimentary ; under
cultivation the tendency to abortion travels downwards and out-
wards, and all the flowers become rudimentary ; but the abortive
stamens and pistils are not so small in the lower as in the upper
flowers. In the Viburnum opulus, on the other hand, the outer
flowers naturally have their organs of fructification in a rudiment-
ary state, and the corolla is of large size ; under cultivation, the
change spreads to the centre, and all the flowers become affected ;
thus the well-known Snow-ball bush is produced. In the Compo-
sitae, the so-called doubling of the flowers consists in the greater
development of the corolla of the central florets, generally accom-
panied with some degree of sterility ; and it has been observed e8
that the progressive doubling invariably spreads from the circum-
ference to the centre, — that is, from the ray florets, which so often
include rudimentary organs, to those of the disc. I may add, as
bearing on this subject, that with Asters, seeds taken from the
florets of the circumference have been found to yield the greatest
number of double flowers.87 In these several cases we have a natu-

83 Youatt on Cattle, 1884, p. 174. i. p. 243.

84 'Encyclop. Method.,' 1820, p. 483: 88 Mr. Beaton, in 'Journal of Horti-
$ee p. 500, on the Indian zebu casting"its culture,' May 21, 1861, p. 133.

horns. Similar cases in European cat- 87 Lecoq, ' De la Fecondation,' 1862,

tie were given in the third chapter. p. 233.
65 Pallas, ' Travels,' Eng.translat., vol.

Chap. XXIV. ARRESTED DEVELOPMENT 381

ral tendency in certain parts to become rudimentary,,and this under
culture spreads either to, or from, the axis of the plant. It deserves
notice, as shoving how the same laws {govern the changes which
natural species and artificial varieties undergo, that in a series of
species in the genus Carthamus, one of the Composite, a tendency
in the seeds to the abortion of the pappus may be traced extending
from the circumference to the centre of the disc : thus, according to
A. de Jussieu,88 the abortion is only partial in Carthamus cretin?.?,
but more extended in C. lanatus; for in this species two or three
alone of the central seeds are furnished with a pappus, the surround-
ing seeds being either quite naked or furnished with a few hairs ;
and lastly, in C. tinctorius, even the central seeds are destitute of
pappus, and the abortion is complete.

With animals and plants under domesticaHon, when an organ
disappears, leaving only a rudiment, the loss has generally been
sudden, as with hornless and tailless breeds ; and such cases may
be ranked as inherited monstrosities. But in some few cases the
loss has been gradual, and has been partly effected by selection, as
with the rudimentary combs and wattles of certain fowls. We have
also seen that the wings of some domesticated birds have been
slightly reduced by disuse, and the great reduction of the wings in
certain silk-moths, with mere rudiments left, has probably been
aided by disuse.

With species in a state of nature, rudimentary organs are so ex-
tremely common that scarcely one can be named which is wholly
free from a blemish of this nature. Such organs are generally
variable, as several naturalists have observed ; for, being useless,
they are not regulated by natural selection, and they are more or
less liable to reversion. The same rule certainly holds good with
parts which have become rudimentary under domestication. We
do not know through what steps under nature rudimentary organs
have passed in being reduced to their present condition ; but we so
incessantly see in species of the same group the finest gradations
between an organ in a rudimentary and perfect state, that we are
led to believe that the passage must have been extremely gradual.
It may be doubted whether a change of structure so abrupt as the
sudden loss of an organ would ever be of service to a species in a
state of nature ; for the conditions to which all organisms are close-
ly adapted usually change very slowly. Even if an organ did sud-
denly disappear in some one individual by an arrest of development,
intercrossing with the other individuals of the same species would
cause it to reappear in a more or less perfect manner, so that its

88 ' Annates du Museum,' torn. vi. p. 319.

382 LAWS OF VARIATION. Chap. XXIV.

final reduction could only be effected by the slow process of con-
tinued disuse or natural selection. It is much more probable that,
from changed habits of life, organs first become of less and less use,
and ultimately superfluous ; or their place may be supplied by some
other organ ; and then disuse, acting on the offspring through in-
heritance at corresponding periods of life, would go on reducing the
organ ; but as most organs could be of no use at an early embry-
onic period, they would not be affected by disuse ; consequently
they would be preserved at this stage of growth, and would remain
as rudiments. In addition to the effects of disuse, the principle of
economy of growth, already alluded to in this chapter, would lead
to the still further reduction of all superfluous parts. With respect
to the final and total suppression or abortion of any organ, another
and distinct principlfe, which will be discussed in the chapter on
pangenesis, probably takes a share in the work.

With animals and plants reared by man there is no severe or re-
current struggle for existence, and the principle of economy will
not come into action. So far, indeed, is this from being the case,
that in some instances organs, which are naturally rudimentary in
the parent-species, become partially redeveloped in the domesticated
descendants. Thus cows, like most other ruminants, properly have
four active and two rudimentary mammae ; but in our domesticated
animals, the latter occasionally become considerably developed and
yield milk. The atrophied mammae, which, in male domesticated
animals, including man, have in some rare cases grown to full size
and secreted milk, perhaps offer an analogous case. The hind feet
of dogs include rudiments of a fifth toe, and in certain large breeds
these toes, though still rudimentary, become considerably develop-
ed and are furnished with claws. In the common Hen, the spurs
and comb are rudimentary, but in certain breeds these become, in-
dependently of age or disease of the ovaria, well developed. The
stallion has canine teeth, but the mare has only traces of the alve-
oli, which, as I am informed by the eminent veterinary Mr. G. T.
Brown, frequently contain minute irregular nodules of bone. These
nod ales, however, sometimes become developed into imperfect
teeth, protruding through the gums and coated with enamel ; and
occasionally they grow to a third or even a fourth of the length of
the canines in the stallion. With plants I do not know whether
the redevelopment of rudimentary organs occurs more frequently
under culture than under nature. Perhaps the pear-tree may be a
case in point, for when wild it bears thorns, which though useful
as a protection are formed of branches in a rudimentary condition,
but, when the tree is cultivated, the thorns are reconverted into
branches.

Chap. xxiv. ARRESTED DEVELOPMENT. 383

Finally, though organs which must be classed as rudi-
mentary frequently occur in our domesticated animals
and cultivated plants, these have generally been formed
suddenly, through an arrest of development. They usu-
ally differ in appearance from the rudiments which so
frequently characterise natural species. In the latter,
rudimentary organs have been slowly formed through
continued disuse, acting by inheritance at a correspond-
ing age, aided by the principle of the economy of growth,
all under the control of natural selection. With domesti-
cated animals, on the other hand, the principle of econo-
my is far from coming into action, and their organs, al-
though often slightly reduced by disuse, are not thus
almost obliterated with mere rudiments left.

384 LAWS OF VARIATION. Chap. XXV.

CHAPTER XXV.

LAWS OF VARIATION, continued — CORRELATED VARIA-
BILITY.

EXPLANATION OF TERM — CORRELATION AS CONNECTED" WITH
DEVELOPMENT — MODIFICATIONS CORRELATED WITH THE IN-
CREASED OR DECREASED SIZE OF PARTS — CORRELATED VARIA-
TION OF HOMOLOGOUS PARTS — FEATHERED FEET IN BIRDS
ASSUMING THE STRUCTURE OF THE WINGS — CORRELATION
BETWEEN THE HEAD AND THE EXTREMITIES — BETWEEN THE
SKIN AND DERMAL APPENDAGES — BETWEEN THE ORGANS OF
SIGHT AND HEARING — CORRELATED MODIFICATIONS IN THE
ORGANS OF PLANTS — CORRELATED MONSTROSITIES — CORRELA-
TION BETWEEN THE SKULL AND EARS — SKULL AND CREST OF
FEATHERS — SKULL AND HORNS — CORRELATION OF GROWTH
COMPLICATED BY THE ACCUMULATED EFFECTS OF NATURAL
SELECTION — COLOUR AS CORRELATED WITH CONSTITUTIONAL
PECULIARITIES

All the parts of the organisation are to a certain extent
connected or correlated together ; but the connexion may-
be so slight that it hardly exists, as with compound ani-
mals or the buds on the same tree. Even in the higher
animals various parts are not at all closely related ; for
one part may be wholly suppressed or rendered mon-
strous without any other part of the body being affected.
But in some cases, when one part varies, certain other
parts always, or nearly always, simultaneously vary;
they are then subject to the law of correlated variation.
Formerly I used the somewhat vague expression of corre-
lation of growth, which may be applied to many large
classes of facts. Thus, all the parts of the body are ad-

Cbap. xxv. CORRELATED VARIABILITY. 385

mirably co-ordinated for the peculiar habits of life of each
organic being, and they may be said, "as the Duke of
Argyll insists in his ' Reign of Law,' to be correlated for
this purpose. Again, in large groups of auimals certain
structures always co-exist; for instance, a peculiar form
of stomach with teeth of peculiar form, and such struc-
tures may in one sense be said to be correlated. But
these cases have no necessary connexion with the law to
be discussed in the present chapter ; for we do not know
that the initial or primary variations of the several parts
were in any way related; slight modifications or indivi-
dual differences may have been preserved, first in one and
then in another part, until the final and perfectly co-
adapted structure was acquired ; but to this subject I
shall presently recur. Again, in many groups of animals
the males alone are furnished with weapons, or are orna-
mented Avith gay colors ; and these characters manifestly
stand in some sort of correlation with the male repro-
ductive organs, for when the latter are destroyed these
characters disappear. But it was shown in the twelfth
chapter that the very same peculiarity may become at-
tached at any age to either sex, and afterwards be ex-
clusively transmitted by the same sex at a corresponding
age. In these cases we have inheritance limited by, or
correlated with, both sex and age ; but we have no rea-
son for supposing that the original cause of the variation
was necessai-ily connected with the reproductive organs,
or with the age of the affected being.

In cases of true correlated variation, we are sometimes
able to see the nature of the connexion ; but in most
cases the bond is hidden from us, and certainly differ*
in different cases. We can seldom say which of two
correlated parts first varies, and induces a change in the
other or whether the two are simultaneously produced
by some distinct cause. Correlated variation is an im-
portant subject for us ; for when one part is modified
through continued selection, either by man or under

386 LAWS OF VAKIATTON". Chap. XXV.

nature, other parts of the organisation will be unavoid-
ably modified. From this correlation it apparently fol-
lows that, with our domesticated animals and plants,
varieties rarely or never differ from each other by some
single character alone.

One of the simplest cases of correlation is that a modi-
fication which arises during an early stage of growth
tends to influence the subsequent development of the
same part, as well as of other and intimately connected
parts. Isidore Geoffroy St. Hilaire states ' that this may
constantly be observed with monstrosities in the animal
kingdom ; and Moquin-Tandon 2 remarks, that, as with
plants the axis cannot become monstrous without in
some way affecting the organs subsequently produced
from it, so axial anomalies are almost always accom-
panied by deviations of structure in the appended parts.
We shall presently see that with short-muzzled races of
the dog certain histological changes in the basal elements
of the bones arrest their development and shorten them,
and this affects the position of the subsequently de-
veloped molar teeth. It is probable that certain modi-
fications in the larvae of insects would affect the struc-
ture of the mature insects. But we must be very careful
not to extend this view too far, for, during the normal
course of development, certain members in the same
group of animals are known to pass through an extra-
ordinary course of change, whilst other and closely allied
members arrive at maturity with little change of struc-
ture.

Another simple case of correlation is that with the in-
creased or decreased dimensions of the whole body, or of
any particular part, certain organs are increased or dimin-

1 ' Hist, des Anomalies,' torn. iii. p. the Mollusca, in his great papc* on the

892. Prof. Huxley applies the same Morphology of the Cephalous Mollusca,

principle in accounting for the remark- in ' Phil. Transact.,' 1S53, p. 56.

able, though normal, differences in the 2 ' Elements de Teratologic Veg.,'lS41,

arrangement of the nervous system in p. 118.

Chap. XXV. CORRELATED VARIABILITY. 387

ished in number, or otherwise modified. Thus pigeon-
fanciers have gone on selecting pouters for length of body,
and we have seen that their vertebrae are generally in-
creased in number, and their ribs in breadth. Tumblers
have been selected for their small bodies, and their ribs
and primary wing-feathers are generally lessened in num-
ber. Fantails have been selected for their large, widely-
expanded tails, with numerous tail-feathers, and the cau-
dal vertebrae are increased in size and number. Carriers
have been selected for length of beak, and their tongues
have become longer, but not in strict accordance with the
length of beak. In this latter breed and in others having
large feet, the number of the scutellae on the toes is greater
than in the breeds with small feet. Many similar cases
could be given. In Germany it has been observed that
the period of gestation is longer in large-sized than in
small-sized breeds of cattle. With our highly-improved
animals of all kinds the period of maturity has advanced,
both with respect to the full growth of the body and the
period of reproduction; and, in correspondence with this,
the teeth are now developed earlier than formerly, so
that, to the surprise of agriculturists, the ancient rules
for judging the age of an animal by the state of its teeth
are no longer trustworthy.8

Correlated Variation of Homologous Parts. — Parts
which are homologous tend to vary in the same manner ;
and this is what might have been expected, for such
ports are identical in form and structure during an early
period of embryonic development, and ai'e exposed in the
egg or womb to similar conditions. The symmetry, in
most kinds of animals, of the corresponding or homologous
organs on the right and left sides of the body, is the
simplest case in point ; but this symmetry sometimes fails,
as with rabbits having only one ear, or stags with one

8 Prof. J. B. Simonds, on the Age of the Ox, Sheep, 4c, quoted in ' Gard. Chro-
nicle,' 1S54, p. 5SS.

388 LAWS OF VARIATION" Chap. XXV

horn, or with many-horned sheep which sometimes carry
an additional horn on one side of their heads. With flow-
ers which have regular corollas, the petals generally vary
in the same manner, as we see in the same complicated
and elegant pattern, on the flowers of the Chinese pink ;
but with irregular flowers, though the petals are of course
homologous, this symmetry often fails, as with the vari-
eties of the Antirrhinum or snapdragon, or that variety
of the kidney-bean {Phase olus multiflorus) which has a
white standard-petal.

In the vertebrata the front and hind limbs are homo-
logous, and they tend to vary in the same manner, as we
see in long and short-legged, or in thick and thin-legged
races of the horse and dog. Isidore Geoffrey * has re-
marked on the tendency of supernumerary digits in man
to appear, not only on the right and left sides, but on the
upper and lower extremities. Meckel has insisted 5 that,
when the muscles of the arm depart in number or arrange-
ment from their proper type, they almost always imitate
those of the leg ; and so conversely the vaiying muscles
of the leg imitate the normal muscles of the arm.

In several distinct breeds of the pigeon and fowl, the legs
and the two outer toes are heavily feathered, so that in
the trumpeter pigeon they appear like little wings. In
the feather-legged bantam the "boots" or feathers, which
grow from the outside of the leg and generally from
the two outer toes, have, according to the excellent au-
thority of Mr. Hewitt,6 been seen to exceed the wing-
feathers in length, and in one case were actually nine
and a half inches in length ! As Mr. Blyth has remark-
ed to me, these leg-feathers resemble the primary wing-
feathers, and are totally unlike the fine down which natu-
rally grows on the legs of some birds, such as grouse and
owls. Hence it may be suspected that excess of food has

* ' Hist, des Anomalies,' torn. i. p. 674. « ' The Poultry Book,' by W. B. Teget-

8 'Quoted by laid. Geoffroy, idem, meier, 1S66, p. 260.

ml.-, A3*

torn. i. p. 635.

Chap. XXV. CORRELATED VARIABILITY. 389

first given redundancy to the plumage, and then that the
law of homologous variation has led to the development
of feathers on the legs, in a position corresponding with
those on the wing, namely, on the outside of the tarsi and
toes. I am strengthened in this belief by the following
curious case of correlation, which for a long time seemed
to me utterly inexplicable, namely, that in pigeons of any
breed, if the legs are feathered, the two outer toes are
partially connected by skin. These two outer toes cor-
respond with our third and fourth toes. Xow, in the
wing of the pigeon or any other bird, the first and fifth
digits are wholly aborted ; the second is rudimentary
and carries the so-called " bastai'd-wing ;" whilst the third
and fourth digits are completely united and enclosed by
skin, together forming the extremity of the wing. So
that in feather-footed pigeons, not only does the exterior
surface support a row of long feathers, like wing-feathers,
but the very same digits which in the wing are complete-
ly united by skin become partially united by skin in the
feet ; and thus by the law of the correlated variation of
homologous parts we can understand the curious connec-
tion of feathered legs and membrane between the two
outer toes.

Andrew Knight7 has remarked that the face or head
and the limbs vary together in general proportions. Com-
pare, for instance, the head and limbs of a dray and race-
horse, or of a greyhound and mastiff. What a monster
a greyhound would appear with the head of a mastiff!
The modern bulldog, however, has fine limbs, but this is
a recently-selected character. From the measurements
given in the sixth chapter, we clearly see that in all the
breeds of the pigeon the length of the beak and the size
of the feet are correlated. The view, which, as before
explained, seems the most pi-obable is, that disuse in all
cases tends to diminish the feet, the beak becoming at

7 A. Walker on Intermarriage, 1SS8, p. 160.

890 LAWS OF VARIATION. Chap. XXV.

the same time through correlation shorter; but that in
those few breeds in which length of beak has been a
selected point, the feet, notwithstanding disuse, have
through correlation inoreased in size.

With the increased length of the beak in pigeons, not
only the tongue increases in length, but likewise the ori-
fice of the nostrils. But the inei-eased length of the ori-
fice of the nostrils perhaps stands in closer correlation
with the development of the corrugated skin or wattle at
the base of the beak ; "for when there is much wattle
round the eyes, the eyelids are greatly increased or even
doubled in length.

There is apparently some correlation even in colour
between the head and the extremities. Thus with horses
a large white star or blaze on the forehead is generally
accompanied by white feet.8 With white rabbits and
cattle, dark marks often co-exist on the tips of the ears
and on the feet. In black and tan dogs of different
breeds, tan-coloured spots over the eyes and tan-coloured
feet almost invariably go together. These latter cases of
connected colouring may be due either to reversion or to
analogous variation, — subjects to which we shall here-
after return, — but this does not necessarily determine the
question of their original correlation. If those naturalists
are correct who maintain that the jaw-bones are homo-
logous with the limb-bones, then we can understand why
the head and limbs tend to vary together in shape and
even in colour ; but several highly competent judges dis-
pute the correctness of this view.

The lopping forwards and downwards of the immense
ears of fancy rabbits is in part due to the disuse of the
muscles, and in part to the weight and length of the ears,
which have been increased by selection during many gene-
rations. Now, with the increased size and changed di-
rection of the ears, not only has the bony auditory meatus

8 ' The Farrier and Naturalist,' vol. i., 1828, p. 456.

Chap. XXV. CORRELATED VARIABILITY. 391

become changed in outline, direction, and greatly in size,
but the whole skull has been slightly modified. This
could be clearly seen in "half-lops" — that is, in rabbits
with one ear alone lopping forward — for the opposite
sides of their skulls were not strictly symmetrical. This
seems to rae a curious instance of correlation, between
hard bones and organs so soft and flexible, as well as so
unimportant under a physiological point of view, as the
external ears. The result no doubt is largely due to
mere mechanical action, that is, to the weight of the ears,
on the same principle that the skull of a human infant is
easily modified by pressure.

The skin and the appendages of hair, feathers, hoofs,
horns, and teeth, are homologous over the whole body.
Every one knows that the colour of the skin and that of
the hair usually vary together ; so that Virgil advises the
shepherd to look whether the mouth and tongue of the
ram are black, lest the lambs should not be purely white.
With poultry and certain ducks we have seen that the
colour of the plumage stands in some connexion with the
colour of the shell of the egg, — that is, with the mucous
membrane which secretes the shell. The colour of the
skin and hair, and the odour emitted by the glands of the
skin, are said 9 to be connected, even in the same race of
men. Generally the hair varies in the same way all over
the body in length, fineness, and curliness. The same
rule holds good with feathers, as we see with the laced
and frizzled breeds both of fowls and pigeons. In the
common cock the feathers on the neck and loins are al-
ways of .a particular shape, called hackles: now in the
Polish breed, both sexes are characterised by a tuft of
feathers on the head ; but through correlation these feath-
ers in the male always assume the form of hackles. The
wing and tail-feathers, though arising from parts not ho-
mologous, vary in length together ; so that long or short

• Godron, ■ Sur l'Espece,' torn. ii. p. 217.

392 LAWS OF VAEIATION. Chap. XXV.

winged pigeons generally have long or short tails. The
case of the Jacobin-pigeon is more curious, for the wing
and tail feathers are remarkably long ; and this appa-
rently has arisen in correlation with the elongated and re-
versed feathers on the back of the neck, which form the
hood.

The hoofs and hair are homologous appendages; and
a careful observer, namely Azara,10 states that in Para-
guay horses of various colours are often born with their
hair curled and twisted like that on the head of a ne-
gro. This ]3eculiarity is strongly inherited. But what is
remarkable is that the hoofs of these horses " are abso-
lutely like those of a mule." The hair also of the
mane and tail is invariably much shorter than usual, be-
ing only from four to twelve inches in length ; so that
curliness and shortness of the hair are here, as with the-
negro, apparently correlated.

With respect to the horns of sheep, Youatt " remarks
that " multiplicity of horns is not found in any breed of
" much value : it is generally accompanied by great
" length and coarseness of the fleece." Several tropical
breeds of sheep, which are clothed with hair instead of
wool, have horns almost like those of a goat. Sturm ia
expressly declares that in different races the more the
wool is curled the more the horns are spirally twisted.
We have seen in the third chapter, where other analo-
gous facts have been given, that the parent of the Mau-
champ breed, so famous for its fleece, had peculiarly
shaped horns. The inhabitants of Angora assert13 that
"only the white goats which have horns wear the fleece
" in the long curly locks that are so much admired ;
" those which are not horned having a comparatively close
" coat." From these cases we may conclude that the

10 ' Quadrupodes du Paraguay,' torn. 1S25, s. 24.

ii. p. 333. l3 Quoted from Conolly, in ' The In-

11 On Sheep, p. 142. dian Field,' Feb. 1S59, vol. ii. p. 266.

12 ' Ueber Racen, Kreuzungen, &c.,'

Chap. XXV. CORRELATED VARIABILITY. 393

hair or wool and the horns vary in a correlated manner.
Those who have tried hydropathy are aware that the fre-
quent application of cold water stimulates the skin ; and
whatever stimulates the skin tends" to increase the
growth of the hair, as is well shown in the abnormal
growth of hair near old inflamed surfaces. Now, Pro-
fessor Low " is convinced that with the different races of
British cattle thin skin and long hair depend on the hu-
midity of the climate which they inhabit. We can thus
see how a humid climate might act on the horns — in the
first place directly on the skin and hair, and secondly by
correlation on the horns. The presence or absence of
horns, moreover, both in the case of sheep and cattle,
acts, as will presently be shown, by some sort of correla-
tion on the skull.

With respect to hair and teeth, Mr. Yarrell 15 found
many of the teeth deficient in three hairless "JEgyp-
tian" dogs, and in a hairless terrier. The incisors, ca-
nines, and premolars suffered most, but in one case all the
teeth, except the large tubercular molar on each side,
were deficient. With man several striking cases have
been recorded 16 of inherited baldness with inherited defi-
ciency, either complete or partial, of the teeth. We see
the same connexion in those rare cases in which the hair
has been renewed in old age, for this has "usually been
accompanied by a renewal of the teeth." I have remark-
ed in a former part of this volume that the great reduc-
tion in the size of the tusks in domestic boars probably
stands in close relation with their diminished bristles, due
to a certain amount of protection ; and that the reap-
pearance of the tusks in boars, which have become feral
and are fully exposed to the weather, probably depends
on the reappearance of the bristles. I may add, though

14 ' Domesticated Animals of the Bri- 18 Sedgwick, ' Brit, and Foreign Medi-

tish Islands,' pp. 807, 868. co-Chirurg. Review,' April 1863, p. 453.

16 ' Proceedings Zoolog. Soc' 1S33, p.
113.

394 LAWS OF VAKIATION. Chap. XXV.

not strictly connected with our present point, that an
agriculturist17 asserts that "pigs with little hair on their
" bodies are most liable to lose their tails, showing a
" weakness of the tegumental structure. It may be pre-
" vented by crossing with a more hairy breed."

In the previous cases deficient hair, and teeth deficient
in number or size, are apparently connected. In the
following cases abnormally redundant hair, and teeth
either deficient or redundant, are likewise connected. Mr.
Crawfurd saw ,8 at the Burmese Court a man, thirty years
old, with his whole body, except the hands and feet, cov-
ered with straight silky hair, which on the shoulders and
spine was five inches in length. At birth the ears alone
were covered. He did not arrive at puberty, or shed his
milk teeth, until twenty years old ; and at this period he
acquired five teeth in the upper jaw, namely four incisors
and one canine, and four incisor teeth in the lower jaw ;
all the teeth were small. This man had a daughter, who
was born with hair within her ears ; and the hair soon
extended over her body. When Captain Yule 19 visited
the Court, he found this girl grown up ; and she presented
a strange appearance with even her nose densely covered
with soft hair. Like her father, she was furnished with
incisor teeth alone. The King had with difficulty bribed
a man to marry her, and of her two children, one, a boy
fourteen months old, had hair growing out of his ears,
with a beard and moustache. This strange peculiarity
had, therefore, been inherited for three generations, with
the molar teeth deficient in the grandfather and mother;
whether these teeth would likewise fail in the infant could
not be told. Here is another case communicated to me
by Mr. Wallace on the authority of Dr. Purland, a dent-
ist : Julia Pastrana, a Spanish dancer, was a remarkably
fine woman, but she had a thick masculine beard and a

17 ' Gard. Chronicle,' 1849, p. 20a 19 ' Narrative of a Mission to the Court

18 ' Embassy to the Court of Avaj! of Ava in 1855,' p. 94.
vol. L p. S20.

Chap, xxv CORRELATED VARIABILITY. 395

hairy forehead ; she was photographed, and her stuffed
skin was exhibited as a show ; but what concerns us is,
that she had in both the upper and lower jaw an irregu
lar double set of teeth, one row being placed within the
other, of which Dr. Purland took a cast. From the re-
dundancy of the teeth her mouth projected, and her face
had a gorilla-like appearance. These cases and those of
the hairless dogs forcibly call to mind the fact, that the
two orders of mammals — namely, the Edentata and Ceta-
cea — which are the most abnormal in their dermal cov-
ering, are likewise the most abnormal either by deficiency
or redundancy of teeth.

The organs of sight and hearing are generally admit-
ted to be homologous, both with' each other and with
the various dermal appendages; hence these parts are
liable to be abnormally affected in conjunction. Mr.
White Cowper says " that in all cases of double microph-
" thalmia brought under his notice he has at the same
" time met with defective development of the dental sys-
" tern." Certain forms of blindness seem to be associated
with the colour of the hair ; a man with black hair and
a woman with light-coloured hair, both of sound consti-
tution, married and had nine children, all of whom were
born blind ; of these children, five " with dark hair and
"brown iris were afflicted with amaurosis; the four
M others, with light-coloured hair and blue iris, had amau-
" rosis and cataract conjoined." Several cases could be
given, showing that some relation exists between vari-
ous affections of the eyes and ears ; thus Liebreich states
that out of 241 deaf-mutes in Berlin, no less than four-
teen suffered from the rare disease called pigmentary
retinitis. Mr. White Cowper and Dr. Earle have re-
marked that inability to distinguish different colours, or
colour-blindness, "is often associated with a correspond-
" ing inability to distinguish musical sounds." M

-° These statements are taken from Review,' July 1861, p. 198; April 1S68,
Mr. Sedgwick, la the ' Medioo-Ohirurg. pp. 455 and 45S. Liebreich is quoted by

396 LAWS OF VARIATION. Chap. XXV.

Here is a more curious case : white cats, if they have
blue eyes, are almost always deaf. I formerly thought
that the rule was invariable, but I have heard of a few
authentic exceptions. The first two notices were pub-
lished in 1829, and relate to English and Persian cats:
of the latter, the Rev. "W. T. Bree possessed a female,
and he states " that of the offspring produced at one and
" the same birth, such as, like the mother, were entirely
" white (with blue eyes) wxere, like her, invariably deaf;
" while those that had the least speck of colour on their
" fur, as invariably possessed the usual faculty of hear-
ing." 21 The Rev. W- Darwin Fox informs me that he
has seen more than a dozen instances of this correlation
in English, Persian, and Danish cats ; but he adds " that,
" if one eye, as I have several times observed, be not blue,
" the cat hears. On the other hand, I have never seen a
" white cat with eyes of the common colour that was
" deaf." In France Dr. Sichel 22 has observed during
twenty years similar facts ; he adds the remarkable case
of the iris beginning, at the end of four months, to grow
dark-coloured, and then the cat first began to hear.

This case of correlation in cats has struck many per-
sons as marvellous. There is nothing unusual in the re-
lation between bine eyes and white fur ; and we have al-
ready seen that the organs of sight and hearing are often
simultaneously affected. In the present instance the
cause probably lies in a slight arrest of development in
the nervous system in connection with the sense-organs.
Kittens during the first nine days, whilst their eyes are
closed, appear to be completely deaf; I have made a
great clanging noise with a poker and shovel close to
their heads, both when they were asleep and awake,
without producing any effect. The trial must not be

Professor Devay, in his ' Manages Con- cas, ' L'Hered. Nat.,' torn. i. p. 428, on

Banguins,' 1862, p. 116. the inheritance of deafness in cats.

« Loudon's 'Mag. of Nat. Hist.,' vol. 22 'Annales des Sc. Nat.' Zoolog., 3rd

1., 1829, pp. C6, 178. See also Dr. P. Lu- series, 1847, torn. viii. p. 239.

Chap. XXV. CORRELATED VARIABILITY. 397

made by shouting close to their ears, for they are, even
-when asleep, extremely sensitive to a breath of air.
Xow as long as the eyes continue closed, the iris is no
doubt blue, for in all the kittens which I have seen this
colour remains for some time after the eyelids open.
Hence, if we suppose the development of the organs of
sight and hearing to be arrested at the stage of the clos-
ed eyelids, the eyes would remain permanently blue and
the ears would be incapable of perceiving sound ; and
we should thus understand this curious case. As, how-
ever, the colour of the fur is determined long before
birth, and as the blueness of the eyes and the whiteness
of the fur are obviously connected, we must believe that
some primary cause acts at an early period.

The instances of correlated variability hitherto given
have been chiefly drawn from the animal kingdom, and
we will now turn to plants. Leaves, sepals, petals, sta-
mens, and pistils are all homologous. In double flowers
we see that the stamens and j>istils vary in the same man-
ner, and assume the form and colour of the petals. In
the double columbine (Aquilegia vulgaris), the successive
whorls of stamens are converted into cornucopias, which
are enclosed within each other and resemble the petals.
In hose-and-hose flowers the sepals mock the petals. In
some cases the flowers and leaves vary together in tint :
in all the varieties of the common pea, which have pur-
ple flowers, a purple mark may be seen on the stipules.
In other cases the leaves and fruit and seeds vary to-
gether in colour, as in a curious pale-leaved variety of the
sycamore, which has recently been described in France,53
and as in the purple-leaved hazel, in which the leaves,
the husk of the nut, and the pellicle round the kernel are
all coloured purple.34 Pomologists can predict to a cer-
tain extent, from the size and appearance of the leaves of

83 ' Gardener's Chron.,' 1S64, p. 1202.

44 Verlot gives several other instances, ' Des Varietes,' 1S65, p. 72.

398 LAWS OF VARIATION. Chap. XXV.

their seedlings, the probable nature of the fruit ; for, as
Van Mons remarks,26 variations in the leaves are gene-
rally accompanied by some modification in the flower,
and consequently in the fruit. In the Serpent melon,
which has a narrow tortuous fruit above a yard in length,
the stem of the plant, the peduncle of the female flower,
and the middle lobe of the leaf, are all elongated in a re-
markable manner. On the other hand, several varieties
of Cucurbita, which have dwarfed stems, all produce, as
Naudin remarks with surprise, leaves of the same pecu-
liar shape. Mr. G. Maw informs me that all the vane-
ties of the scarlet Pelargoniums which have contracted
or imperfect leaves have contracted flowers : the differ-
ence between " Brilliant " and its parent " Tom Thumb"
is a good instance of this. It may be suspected that
the curious case described by Risso,26 of a variety of the
Orange which produces on the young shoots roundfd
leaves with winged petioles, and afterwards elongated
leaves on long but wingless petioles, is connected with the
remarkable change in form and nature which the fruit un-
dergoes during its development.

In the following instance we have the colour and form
of the petals apparently correlated, and both dependent
on the nature of the season. An observer, skilled in the
subject, writes,27 "I noticed, during the year 1842, that
"every Dahlia, of which the colour had any tendency to
" scarlet, was deeply notched — indeed to so great an ex-
" tent as to give the petals the appearance of a saw ; the
" indentures were, in some instances, more than a quarter
"of an inch deep." Again, Dahlias which have their
petals tipped with a different colour from the rest are
very inconstant, and during certain years some, or even
all the flowers, become uniformly coloured ; and it has

ss 'Arbres Fruitiers,' 1836, torn. ii. pp. 28 'Ann. du Museum,' torn. xx. p. 1S8.

204, 226. " 'Gardener's Chron.,' 1843, p. 877.

Chap. XXV. CORRELATED VARIABILITY. 300

been observed with several varieties,38 that when this
happens the petals grow much elongated and lose their
proper shape. This, however, may be due to reversion,
both in colour and form, to the aboriginal species.

In this discussion on correlation, we have hitherto treat-
ed of cases in which we can partly understand the bond
of connexion ; but I will now give cases in which we can-
not even conjecture, or can only very obscurely see, what
is the nature of the bond. Isidore Geoffroy St. Hilaire,
in his work on Monstrosities, insists,29 " que certaines
" anomalies coexistent rarement entr'elles, d'autres fre-
" quemment, d'autres enfin presque constamment, malgre
" la difference tres-grande de leur nature, et quoiqu'elles
" puissent paraitre completement independantesles unes des
"autres." We see something analogous in certain dis-
eases : thus I hear from Mr. Paget that in a rare affection
of the renal capsules (of which the functions are un-
known), the skin becomes bronzed ; and in hereditary
syphilis, both the milk and the second teeth assume a pe-
culiar and characteristic form. Professor Rolleston, also,
informs me that the'incisor teeth are sometimes furnished
with a vascular rim in correlation with intra-pulmonary
deposition of tubercles. In other cases of phthisis and of
cyanosis the nails and finger-ends become clubbed like
acorns. I believe that no explanation has been offered of
these and of many other cases of correlated disease.

What can be more curious and less intelligible than the
fact previously given, on the authority of Mr. Tegetmeier,
that young pigeons of all breeds, which when mature have
white, yellow, silver-blue, or dun-coloured plumage, come
out of the egg almost naked; whereas pigeons of other
coloui'S when first born are clothed with plenty of down ?
White Pea-fowls, as has been observed both in England

•

28 Ibid., 1S45, p. 102. chercb.es sur les Conditions,' 4c, 18C3,

89 ' Hist, des Anomalies,' torn. ill. p. pp. 16, 48.
402. See also M. Camille Darcste, 'Re-

400 LAWS OF VARIATION. Chap. XXV.

and France,30 and as I have myself seen, are inferior in
size to the common coloured kind ; and this cannot be
accounted for by the belief that albinism is always accom-
panied by constitutional weakness ; for white or albino
moles are generally larger than the common kind.

To turn to more important characters : the niata cattle
of the Pampas are remarkable for their short foreheads,
upturned muzzles, and curved lower jaws. In the skull
the nasal and premaxillary bones are much shortened, the
maxillaries are excluded from any junction with the
nasals, and all the bones are slightly modified, even to the
plane of the occiput. From the analogical case of the
dog, hereafter to be given, it is probable that the short-
ening of the nasal and adjoining bones js the proximate
cause of the other modifications in the skull, including
the upward curvature of the lower jaw, though we can-
not follow out the steps by which these changes have
been effected.

Polish fowls have a large tuft of feathers on their
heads ; and their skulls are perforated by numerous holes,
so that a pin can be driven into the brain without touch-
ing any bone. That this deficiency of bone is in some
way connected with the tuft of feathers is clear from tuft-
ed ducks and geese likewise having perforated skulls.
The case would probably be considered by some authors
as one of balancement or compensation. In the chapter
on Fowls, I have shown that with Polish fowls the tuft
of feathers was probably at first small ; by continued
selection it became larger, and then rested on a fleshy or
fibrous mass ; and finally, as it became still larger, the
skull itself became more and more pi-otuberant until it
acquired its present extraordinary structure. Through
correlation with the protuberance of the skull, the shape
and even the relative connexion of the premaxillary and

>° Rev. E. S. Dixon, ' Ornamental Poultry,' 1848, p. Ill ; Isidore Geoffroy, ' Hist.
Anomalies,' torn. 1. p. 211.

Chap. XXV. CORRELATED VARIABILITY. . 401

nasal bones, the shape of the orifice of the nostrils, the
breadth of the frontal bone, the shape of the post-lateral
processes of the frontal and squamosal bones, and the di-
rection of the bony cavity of the ear, have all been modi-
fied. The internal configuration of the skull and the
whole shape of the brain have likewise been altered in a
truly marvellous manner.

After this case of the Polish fowl it would be super-
fluous to do more than refer to the details previously
given on the manner in which the changed form of the
comb, in various breeds of the fowl, has affected the
skull, causing by correlation crests, protuberances, and
depressions on its surface.

With our cattle and sheep the horns stand in close
connexion with the size of the skull, and with the shape
of the frontal bones ; thus Cline 31 found that the skull
of a horned ram weighed five times as much as that of a
hornless ram of the same age. When cattle become
hornless, the frontal bones are " materially diminished
" in breadth towards the poll ;" and the cavities between
the bony plates "are not so deep, nor do they extend
" beyond the frontals." 32

It may be well here to pause and observe how the
effects of correlated variability, of the increased use of
parts, and of the accumulation through natural selection
of so-called spontaneous variations, are in many cases in-
extricably commingled. We may borrow an illustration
from Mr. Herbert Spencer, who remarks that, when the
Irish elk acquired its gigantic horns, weighing above
one hundred pounds, numerous co-ordinated changes of
structure would have been indispensable, — namely, a thick-
ened skull to carry the horns ; strengthened cervical verte-
bra?, with strengthened ligaments ; enlarged dorsal verte-
brae to support the neck, with powerful fore-legs and feet ;

31 ' On the Breeding of Domestic Animals,' 1829, p. 6.

32 Youatton Cattle, 1S31, p. 253.

402 LAWS OF VARIATION. Chap. XXV.

all these parts being supplied with proper muscles, blood-
vessels, and nerves. How then could these admirably-
co-ordinated modifications of structure have been ac-
quired? According to the doctrine which I maintain,
the horns of the male elk were slowly gained through
sexual selection, — that is, by the best-armed males con-
quering the worse-armed, and leaving a greater number
of descendants. But it is not at all necessary that the
several parts of the body should have simultaneously
varied. Each stag presents individual differences, and
in the same district those which had slightly heavier horns,
or stronger necks, or stronger bodies, or were the most
courageous, would secure the greater number of does, and
consequently leave a greater number of offspring. The
offspring would inherit, in a greater or less degree, these
same qualities, would occasionally intercross with each
other, or with other individuals varying in some favour-
able manner; and of their offspring, those which were
the best endowed in any respect would continue multi-
plying ; and so onwards, always progressing, sometimes
in one direction, and sometimes in another, towards the
present excellently Co-ordinated structure of the male elk.
To make this clear, let us reflect on the probable steps,
as shown in the twentieth chapter, by which our race and
dray-horses have arrived at their present state of excel-
lence ; if we could view the whole series of intermediate
forms between one of these animals and an early unim-
proved progenitor,* we should behold a vast number of
animals, not equally improved in each generation through-
out their entire structure, but sometimes a little more in
one point, and sometimes in another, yet on the whole
gradually approaching in character to our present race
or dray-horses, which are so admirably fitted in the one
case for fleetness and in the other for draught.

Although natural selection would thus 33 tend to give

93 Mr. Herbert Spencer (' Principles takes a different view ; and in one place
of Biology,' 1S64, vol. i. pp. 452, 468) remarks : " We have seen reason to

Chap. XXV. CORRELATED VARIABILITY. 403

to the male elk its present structure, yet it is probable
that the inherited influence of use has played an equal or
more important part. As the horns gradually increased
in weight, the muscles of the neck, with the bones to
which they are attached, would increase in size and
strength ; and these parts would react on the body and
legs. Nor must we overlook the fact that certain parts
of the skull and the extremities would, judging by ana-
logy, tend from the first to vary in a correlated maimer.
The increased weight of the horns would also act directly
on the skull, in the same manner as, when one bone is
removed in the leg of a dog, the other bone, which has
to carry the whole weight of the body, increases in
thickness. But from the facts given with respect to horned
and hornless cattle, it is probable that the horns and skull
would immediately act on each other through the prin-
ciple of correlation. Lastly, the growth and subsequent
wear and tear of the augmented muscles and bones would
require an increased supply of blood, and consequently
an increased supply of food; and this again would re-
quire increased powers of mastication, digestion, respira-
tion, and excretion.

Colour as Correlated icith Constitutional Peculiarities.

It is an old belief that with man there is a connexion
between complexion and constitution ; and I find that
some of the best authorities believe in this to the present
day.34 Thus Dr. Beddoe by his tables shows 3B that a re-

" think that, as fast as essential faculties can do little in modifying the higher ani-

" multiply, and as fast as the number of mals surprises me, seeing that man's se-

" organs that co-operate in any given lection has undoubtedly effected much

" function increases, indirect cquilibra- with our domesticated quadrupeds and

" tion through natural selection becomes birds.

" less and less capable of producing spe- 34 Dr. Prosper Lucas apparently dis-

" cific adaptations; and remains fully believes in any such connexion,' L'He-

" capable only of maintaining the gen- red. Nat.,' torn. ii. pp. 8S-94.

" eral fitness of constitution to condi- 35 ' British Medical Journal,' 1862, p.

" tions." This view that natural selection 438.

404 LAWS OF VARIATION. Chap. XXV.

lation exists between liability to consumption and the co-
lour of the hair, eyes, and skin. It has been affirmed36
that, in the French army which invaded Russia, soldiers
having a dark complexion, from the southern parts of
Europe, withstood the intense cold better than those with
lighter complexions from the North ; but no doubt such
statements are liable to error.

In the second chapter on Selection I have given several
cases proving that with animals and plants differences in
colour are correlated with constitutional differences, as
shown by greater or less immunity from certain diseases,
from the attacks of parasitic plants and animals, from
burning by the sun, and from the action of certain poisons.
When all the individuals of any one variety possess an
immunity of this nature, we cannot feel sure that it stands
in any sort of correlation with their colour ; but when
several varieties of the same species, which are similarly
coloured, are thus characterised, whilst other coloured va-
rieties are not thus favoured, we must believe in the exist-
ence of a correlation of this kind. Thus in the United
States purple-fruited plums of many kinds are far more
affected by a certain disease than green or yellow-fruited
varieties. On the other hand, yelloW-fleshed peaches of
various kinds suffer from another disease much more than
the white-fleshed varieties. In the Mauritius red sugar-
canes are much less affected by a particular disease than
the white canes. White onions and verbenas are the
most liable to mildew ; and in Spain the green-fruited
grapes suffered from the vine-disease more than other co-
loured varieties. Dark-coloured pelargoniums and verbe-
nas are more scoi'ched by the sun than varieties of other
colours. Red wheats are believed to be hardier than
Avhite; whilst red-flowered hyacinths were more injured
during one particular winter in Holland than other co-
loured varieties. With animals, white terriers suffer most

86 Boudin, ' Geograph. Medicale,' torn. i. p. 406.

Chap. XXV. CORRELATED VARIABILITY. 405

from the distemper, white chickens from a parasitic worm
in their trachea?, white pigs from scorching by the sun,
and white cattle from flies ; but the caterpillars of the
silk-moth which yield white cocoons suffered in France
less from the deadly parasitic fungus than those produc-
ing yellow silk.

The cases of immunity from the action of certain vege-
table poisons, in connexion with colour, are more inter-
esting, and are at present wholly inexplicable. I have
already given a remarkable instance, on the authority of
Professor "Wyman, of all the hogs, excepting those of
a black colour, suffering severely in Florida from eating
the root of the Lachnanthes tinctoria. According to Spi-
nola and others,37 buckwheat {Polygonum fagopyrum),
when in flower, is highly injurious to white or white-
spotted pigs, if they are exposed to the heat of the sun,
but is quite innocuous to black pigs. By two accounts,
the Hypericum crispum in Sicily is poisonous to white
sheep alone ; their heads swell, their wool falls off, and
they often die ; but this plant, according to Lecce, is poi-
sonous only when it grows in swamps ; nor is this impro-
bable, as Ave know how readily the poisonous principle in
plants is influenced by the conditions under which they
grow.

Three accounts have been published in Eastern Prus-
sia, of white and white-spotted horses being greatly in-
jured by eating mildewed and honeydewed vetches;
every spot of skin bearing white hairs becoming in-
flamed and gangrenous. The Rev. J. Rodwell informs
me that his father turned out about fifteen cart-horses
into a field of tares which in parts swarmed with black
aphides, and which no doubt were honeydewed, and pro-
bably mildewed ; the horses, with two exceptions, were

37 This fact and the following cases, Prof. Heusinger, in ' Wochenschrift fur
when not stated to the contrary, are Heilkuade,' May 1S46, s. 2TT.
taken from a very curiou9 paper by

406 LAWS OF VARIATION". Chap. XXV.

chesnuts and bays with white marks on their faces and
pasterns, and the white parts alone swelled and became
angry scabs. The two bay horses with no white marks
entirely escaped all injury. In Guernsey, when horses
eat fools' parsley (JEtkusa cynapium) they are some-
times violently purged ; and this plant " has a peculiar
" effect on the nose and lips, causing deep cracks and
" ulcers, particularly on horses with white muzzles." 3S
With cattle, independently of the action of any poison,
cases have been published by Youatt and Erdt of cuta-
neous diseases with much constitutional disturbance (in
one instance after exposure to a hot sun) affecting every
single point which bore a white hah*, but completely
passing over other parts of the body. Similar cases
have been observed with horses.39

We thus see that not only do those parts of the skin
which bear white hair differ in a remarkable manner
from those bearing hair of any other colour, but that in
addition some great constitutional difference must stand
in correlation with the colour of the hair; for in the
above-mentioned cases, vegetable poisons caused fever,
swelling of the head, as well as other symptoms, and
even death, to all the white or white-spotted animals.

88 Mr. Mogford, in the ' Veterinarian,' 39 ' Edinburgh Veterinary Journal,*

quoted in 'The Field,' Jan. 22, 1SG1, p. Oct. 1860, p. 347.
545.

Chap. XXVI. AFFINITY OF HOMOLOGOUS PARTS. 407

CHAPTER XXYI.

LAWS OF VARIATION, continued — SUMMARY.

ON THE AFFINITY AND COHESION OF HOMOLOGOUS PARTS — ON THE
VARIABILITY OF MULTIPLE AND HOMOLOGOUS PARTS — COMPEN-
SATION OF GROWTH — MECHANICAL PRESSURE — RELATIVE POSI-
TION OF FLOWERS WITH RESPECT TO THE AXIS OF THE PLANT,
AND OF SEEDS IN THE CAPSULE, AS INDUCING VARIATION — ANA-
LOGOUS OR PARALLEL VARIETIES — SUMMARY OF THE THREE
LAST CHAPTERS.

On the Affinity of Homologous Parts. — This law was
first generalised by GeoflVoy Saint Hilaire, under the ex-
pression of La loi de Vaffinite de soipour soi. It has been
fully discussed and illustrated by his son, Isidore Geof-
froy, with respect to monsters in the animal kingdom,1
and by Moquin-Tandon, with respect to monstrous plants.
When similar or homologous parts, whether belonging
to the same embryo or to two distinct embryos, are
brought during an early stage of development into con-
tact, they often blend into a single part or organ ; and
this complete fusion indicates some mutual affinity be-
tween the parts, otherwise they would simply cohere.
"Whether any power exists which tends to bring homolo-
gous parts into contact seems more doubtful. The ten-
dency to complete fusion is not a rare or exceptional
fact. It is exhibited in the most striking manner by
double monsters. Nothing can be more extraordinary
than the manner, as shown in various published plates,

» ' Hist, des Anomalies,' 1S32, torn i. pp. 22, 537-556; torn. Hi. p. 462.

408 LAWS OF VARIATION. Chap. XXVI.

in which the corresponding parts of two embryos become
intimately fused together. This is perhaps best seen in
monsters with two heads, which are united, summit to
summit, or face to face, or, Janus-like, back to back, or
obliquely side to side. In one instance of two heads
united almost face to face, but a little obliquely, four
ears were developed, and on one side a perfect face,
which was manifestly formed by the union of two half-
faces. Whenever two bodies or two heads are united,
each bone, muscle, vessel, and nerve on the line of junc-
tion seems to seek out its fellow, and becomes completely
fused with it. Lereboullet,2 who carefully studied the
development of double monsters in fishes, observed in
fifteen instances the steps by which two heads gradually
became fused into one. In this and other such cases, no
one, I presume, supposes that the two already formed
heads actually blend together, but that the correspond-
ing parts of each head grow into one during the further
progress of development, accompanied as it always is
with incessant absorption and renovation. Double mon-
sters were formerly thought to be formed by the union
of two originally distinct embryos developed upon dis-
tinct vitelli ; but now it is admitted that " their produc-
" tion is due to the spontaneous divarication of the em-
bryonic mass into two halves ; " 3 this, however, is effected
by different methods. But the belief that double mon-
sters originate from the division of one germ, does not
necessarily affect the question of subsequent fusion, or
render less true the law of the affmity of homologous
parts.

The cautious and sagacious J. Miiller,4 when speaking
of Janus-like monsters, says, that " without the supposi-

2 '■ Comptes Rendus,' 1855, pp. 855, * ' Elements of Physiology,' Enp.
1329. translat,, vol. i., 183S, p. 412. With

3 Carpenter's ' Corap. Phys.,' 1854, p. respect to Vrolik, see Todd's ' Cyclop.
480 ; see also Camille Dareste, ' Comptes of Anat. and Phys.,' vol. iv., 1849-52, p.
Rendus,' March 20th, 1865, p. 562." 973.

Chap. XXVI. AFFINITY OF HOMOLOGOUS PARTS. 409

" tion that some kind of affinity or attraction is exerted
" between corresponding parts, unions of this kind are
"inexplicable." On the other hand, Vrolik, and he is
followed by others, disputes this conclusion, and argues
from the existence of a whole series of monstrosities,
graduating from a perfectly double monster to a. mere
rudiment of an additional digit, that " an excess of for-
" mative power " is the cause and origin of every mon-
strous duplicity. That there are two distinct classes of
cases, and that parts may be doubled independently of
the existence of two embryos, is certain ; for a single em-
bryo, or even a single adult animal, may produce doubled
organs. Thus Valentin, as quoted by Vrolik, injured the
caudal extremity of an embryo, and three days afterwards
it produced rudiments of a double pelvis and of double
hind limbs. Hunter and others have observed lizards
with their tails reproduced and doubled. When Bonnet
divided longitudinally the foot of the salamander, seve-
ral additional digits were occasionally formed. But nei-
ther these cases, nor the perfect series from a double
monster to an additional digit, seem to me opposed to
the belief that corresponding parts have a mutual affinity,
and consequently tend to fuse together. A part may be
doubled and remain in this state, or the two parts thus
formed may afterwards through the law of affinity be-
come blended; or two homologous parts in two separate
embryos may, through the same principle, unite and form
a single part.

The law of the affinity and fusion of similar parts ap-
plies to the homologous organs of the same individual
animal, as well as to double monsters. Isidore Geoffrov
gives a number of instances of two or more digits, of two
whole legs, of two kidneys, and of several teeth becom-
ing symmetrically fused together in a more or less perfect
manner. Even the two eyes have been known to unite
into a single eye, forming a cyclopean monster, as have
the two ears, though naturally standing so far apart.

410 LAWS OF VARIATION. Chap. XXVI.

As Geoffroy remarks, these facts illustrate in an admira-
ble manner the normal fusion of various organs Avhich
during an early embryonic period are double, but which
afterwards always unite iuto a single median organ.
Organs of this nature are generally found in a perma-
nently double condition in other members of the same
class. These cases of normal fusion appear to me to
aflbrt the strongest support in favour of the present law.
Adjoining parts which are not homologous sometimes
cohere ; but this cohesion appears to result from mere
juxtaposition, and not from mutual affinity.

In the vegetable kingdom Moquin-Tandon 5 gives a
long list of cases, showing how frequently homologous
parts, such as leaves, petals, stamens, and pistils, as well
as aggregates of homologous parts, such as buds, flowers,
and fruit, become blended into each other with perfect
symmetry. It is interesting to examine a compound
flower of this nature, formed of exactly double the pro-
per number of sepals, petals, stamens, and pistils, with
each whorl of organs circular, and with no trace left of
the process of fusion. The tendency in homologous parts
to unite during their early development, Moquin-Tandon
considers as one of the most striking laws governing the
production of monsters. It apparently explains a multi-
tude of cases, both in the animal and vegetable king-
doms ; it throws a clear light on many nonnal structures
which have evidently been formed by the union of ori-
ginally distinct parts, and it possesses, as we shall see in
a future chapter, much theoretical interest.

On the Variability of Multiple and Homologous Parts.
— Isidore GeoffVoy 6 insists that, when any part or
organ is repeated many times in the same animal, it is
particularly liable to vary both in number and structure.
With respect to number, the proposition may, I think,

5 ' Teratologie Veg ,' 1S41, livre iii.

• ' Hist, des Anomalies,' torn. iii. pp. 4, 5, 6.

Chap. xxvi. COMPENSATION. 411

be considered as fully established ; but the evidence is
chiefly derived from organic beings liviug under their
natural conditions, with which we are not here concerned.
"When the vertebra?, or teeth, or rays in the fins of fishes,
or feathers in the tails of birds, or petals, stamens, pistils,
and seeds in plants, are very numerous, the number is
generally variable. The explanation of this simple fact
is by no means obvious. "With respect to the variability
in structure of multiple parts, the evidence is not so de-
cisive ; but the fact as far as it may be trusted, probably
depends on multiple parts being of less physiological im-
portance than single parts ; consequently their perfect
standard of structure has been less rigorously enforced
by natural selection.

Compensation of Grotcth, or Balancement. — This law,
as applied to natural species, was propounded by Goethe
and Geoflroy St. Hilaire at nearly the same time. It
implies that, when much organised matter is used in
building up some one part, other parts are starved and
become reduced. Several authors, especially botanists,
believe in this law ; others reject it. As far as I can
judge, it occasionally holds good ; but its importance
has probably been exaggerated. It is scarcely possible
to distinguish between the supposed effects of such com-
pensation of growth, and the effects of long-continued
selection, which may at the same time lead to the aug-
mentation of one part and the diminution of another.
There can be no doubt that an oi'gan may be greatly in-
creased without any corresponding diminution in the ad-
joining parts. To recur to our former illustration of the
Irish elk, it may be asked what part has suffered in con-
sequence of the immense development of the horns ?

It has already been observed that the struggle for ex-
istence does not bear hard on our domesticated produc-
tions ; consequently the principle of economy of growth
will seldom affect them, and we ought not to expect to

412 LAWS OF VARIATION. Chap. XXVI.

find frequent evidence of compensation. We have, how-
ever, some such cases. Moquin-Tandon describes a mon-
strous bean,7 in which the stipules were enormously de-
veloped, and the leaflets apparently in consequence com-
pletely aborted; this case is interesting, as it represents
the natural condition of Lathyrus aphaca, with its sti-
pules of great size, and its leaves reduced to mere threads,
which act as tendrils. De Candolle8has remarked that
the varieties of Haphanus sativus which have small roots
yield numerous seed, valuable from containing oil, whilst
those with large roots are not productive in this latter
respect ; and so it is with JBrassica asperifolia. The
varieties of the potato which produce tubers very early
in the season rarely bears flowers ; but Andrew Knight,9
by checking the growth of the tubers, forced the plants
to flower. The varieties of Cucurbita pepo which pro-
duce large fruit yield, according to ^Nfaudin, few in num-
ber ; whilst those producing small fruit yield a vast num-
ber. Lastly, I have endeavoured to show in the eighteenth
chapter that with many cultivated plants unnatural treat-
ment checks the full and proper action of the reproductive
organs, and they are thus rendered more or less sterile;
consequently, in the way of compensation, the fruit be-
comes greatly enlarged, and, in double flowers, the petals
are greatly increased in number.

With animals, it has been found difficult to produce
cows which should first yield much milk, and afterwards
be capable of fattening well. With fowls which have
large topknots and beards the comb and wattles are gen-
erally much reduced in size. Perhaps the entire absence
of the oil-gland in fantail pigeons may be connected with
the great development of their tails. -

7 "Teratologic Veg.,' p. 156. See also 8 'Meraoires du Museum,' &c, torn,

my paper on climbing plants in ' Jour- viii. p. 178. ,

nal of Linn. Soc. Bot.,' vol. ix., 1S65, p. 9 Loudon's 'Encyclop. of Gardening,'

114. p. 829.

Chap. XXVt. MECHANICAL PRESSURE. 413

Mechanical Pressure as a Cause of Modifications. — In
some few cases there is reason to believe that mere me-
chanical pressure has affected certain structures. Every
one knows that savages alter the shape of their infants'
skulls by pressure at an early age ; but there is no reason
to believe that the result is ever inherited. Nevertheless
Vrolik and Weber 10 maintain that the shape of the human
head is influenced by the shape of the mother's pelvis.
The kidneys in different birds differ much in form, and
St. Ange ll believes that this is determined by the form
of the pelvis, which again, no doubt, stands in close rela-
tion with their various habits of locomotion. In snakes,
the viscera are curiously displaced, in comparison with
their position in other vertebrates; and this has been
attributed by some authors to the elongation of their
bodies ; but here, as in so many previous cases, it is im-
possible to disentangle any direct result of this kind from
that consequent on natural selection. Godron has ar-
gued12 that the normal abortion of the spur on the inner
side of the flower in Corydalis, is caused by the buds
being closely pressed at a very early period of growth,
whilst under ground, against each other and against the
stem. Some botanists believe that the singular differ-
ence in the shape both of the seed and corolla, in the in-
terior and exterior florets in certain compositous and
umbelliferous plants, is due to the pressure to which the
inner florets are subjected ; but this conclusion is doubtful.
The facts just given do not relate to domesticated pro-
ductions, and therefore do not strictly concern us. But
here is a more appropriate case : H. Miiller 13 has shown
that in short-faced races of the dog some of the molar
teeth are placed in a slightly different position from that
which they occupy in other dogs, especially in those hav-

10 Pilchard, 'Phys. Hist, of Mankind,' ia 'Comptes Rendus,' Dec. 1SG4, p.
1851, vol. i. p. 324. 1039.

11 'Annates des So. Nat.,' 1st series, 13 Ceber Fotale Rachites, lWur&bur<*.
torn. xix. p. 32T. er Medicin. Zeitschrift,' 18G0, B. i. s. 263.

414 LAWS OF VARIATION. Chap. XXVI.

m

ing elongated muzzles ; and as he remarks, any inherited
change in the arrangement of the teeth deserves notice,
considering their classificatory importance. This differ-
ence in position is due to the shortening of certain facial
bones, and the consequent want of space ; and the short-
ening results from a peculiar and abnormal state of the
basal cartilages of the bones.

Relative Position of Flowers loith respect to the Axis, and
of Seeds in the Capsule, as inducing Variation.

In the thirteenth chapter various peloric flowers were described,
and their production was shown to be due either to arrested de-
velopment, or to reversion to a primordial condition. Moquin-Tan-
don has remarked that the flowers which stand on the summit of
the main stem or of a lateral branch are more liable to become
peloric than those on the sides ; 14 and he adduces, amongst other
instances, that of Teucrium campanulatum. In another Labiate
plant grown by me, viz. the Galedbdolon luteum, the peloric flowers
were always produced on the summit of the stem, where flowers are
not usually borne. In Pelargonium, a single flower in the truss is
frequently peloric, and when this occurs I have during several years
invariably observed it to be the central flower. This is of such
frequent occurrence that one observer 15 gives the names of ten va-
rieties flowering at the same time, in every one of which the central
flower was peloric. Occasionally more than one flower in the truss
is peloric, and then of course the additional ones must be lateral.
These flowers are interesting as showing how the whole structure
is correlated. In the common Pelargonium the upper sepal is pro-
duced into a nectary which coheres with the flower-peduncle ; the
two upper petals differ a little in shape from the three lower ones,
and are marked with dark shades of coloilr ; the stamens are gra-
duated in length and upturned. In the peloric flowers, the nectary
aborts ; all the petals become alike both in shape and colour ; the
stamens are generally reduced in number and become straight, so
that the whole flower resembles that of the allied genus Erodium.
The correlation between these changes is well shown when one of
the two upper petals alone loses its dark mark, for in this case the

14 ' Teratologic Veg.,' p. 192. Dr. M. lish it.

Masters informs me that he doubts the 15 ' Journal of Horticulture,' July 2nd,

truth of this conclusion ; but the facts 1861, p. 253.
to be giren seem to be sufficient to estab-

Chap. XXVI. RELATIVE POSITION OF PARTS. 415

nectary does not entirely abort, but is usually much reduced in
length.16

Morren has described lr a marvellous flask-shaped flower of the
Calceolaria, nearly four inches in length, which was almost com-
pletely peloric ; it grew on the summit of the plant, with a normal
flower on each side ; Prof. Westwood also has described1" three similar
peloric flowers, which all occupied a central position on the flower-
brancbes. In the Orchideous genus, Phalamopsis, the terminal
flower has been seen to become peloric.

In a Laburnum-tree I observed that about a fourth part of the
racemes produced terminal flowers which had lost their papiliona-
ceous structure. These were produced after almost all the other
flowers on the same racemes had withered. The most perfectly
pelorised examples had six petals, each marked with black striae
like those on the standard-petal. The keel seemed to resist the
change more than the other petals. Dutrochet has described 19 an
exactly similar case in France, and I believe these are the only two
instances of pelorism in the laburnum which have been recorded.
Dutrochet remarks that the racemes on this tree do not properly
produce a terminal flower, so that, as in the case of the Galeobdo-
lon, their position as well as their structure are both anomalies,
which no doubt are in some manner related. Dr. Masters has briefly
described another leguminous plant,20 namely, a species of clover,
in which the uppermost and central flowers were regular or had lost
their papilionaceous structure. In some of these plants the flower-
heads were also proliferous.

Lastly, Linaria produces two kinds of peloric flowers, one having
simple petals, and the other having them all spurred. The two
forms, as Xaudiu remarks,21 not rarely occur on the same plant, but
in this case the spurred form almost invariably stands on the sum-
mit of the spike.

The tendency in the terminal or central flower to become peloric
more frequently than other flowers, probably results from " the
" bud which stands on the end of a shoot receiving the most sap ;

" It would be worth trial to fertilise 18 ' Gardener's Chronicle,' 1866, p. 612.

with the same pollen the central and For the Phalaenopsis, see idem, 1867, p.

lateral flowers of the pelargonium, and 211.

of some other highly cultivated plants, le ' Memoires . . des Vegetaux,' 1837,

protecting them of course from insects : torn. ii. p. 170.

then to sow the seed separately, and ob- 20 ' Journal of Horticulture,' July 23,

serve whether the one or the other lot 1861, p. 311.

of seedlings varied the most. 21 ' Nouvelles Archives du Museum,'

17 Quoted in 'Journal of Horticulture,' torn. i. p. 137.
Feb. 24, 1863, p. 152.

416 LAWS OF VARIATION". Chap. XXVL

"it grows out into a stronger shoot than those situated lower
down." 22 I have discussed the connection between pelorism and a
central position, partly because some few plants are known nor-
mally to produce a terminal flower different in structure from the
lateral ones ; but chiefly on account of the following case, in which
we see a tendency to variability or to reversion connected with the
same position. A great judge of Auriculas 23 states that when an
Auricula throws up a side bloom it is pretty sure to keep its charac-
ter; but that if it grows from the centre or heart of the plant,
whatever the colour of the edging ought to be, " it is just as likely
" to come in any other class as in the one to which it properly
" belongs." This is so notorious a fact, that some florists regularly
pinch off the central trusses of flowers. Whether in the highly
improved varieties the departure of the central trusses from their
proper type is due to reversion I do not know. Mr. Dombrain insists
that, whatever may be the commonest kind of imperfection in each
variety, this is generally exaggerated in the central truss. Thus
one variety " sometimes has the fault of producing a little green
" floret in the centre of the flower," and in central blooms these
become excessive in size. In some central blooms, sent to me by
Mr. Dombrain, all the organs of the flower were rudimentary in
structure, of minute size, and of a green colour, so that by a little
further change all would have been converted into small leaves. In
this case we clearly see a tendency to prolification — a term which, I
may explain to those who have never attended to botany, means
the production of a branch or flower, or head of flowers out of an-
other flower. Now Dr. Masters 24 states that the central or upper-
most flower on a plant is generally the most liable to prolification.
Thus, in the varieties of the Auricula, the loss of their proper cha-
racter and a tendency to prolification, and in other plants a tendency
to prolification and pelorism, are all connected together, and are
due either to arrested development, or to reversion to a former con-
dition.

The following is a more interesting case ; Metzger 25 cultivated in
Germany several kinds of maize brought from the hotter parts of
America, and he found, as has been previously described, that in
two or three generations the grains became greatly changed in
form, size, and colour ; and with respect to two races he expressly

22 Hugo von Mohl, ' The Vegetable 29th, p. 8-3.

Ctll,' Eng. tr., 1S52, p. "G. 24 ' Transact. Linn. Soc.,' vol. xxiii.,

23 The Rev. II. H. Dombrain, in ' Jour- 1S61, p. 360.

nal of Horticulture,' 1S61, June 4th, p. 25 'Die Getreidearten,' 1843, s. 203,

174 ; and June 25th, p. 234 ; 1S62, April 209.

Chap. XXVI. ANALOGOUS VARIATION. 417

states that in the first generation, whilst the lower grains on each
head retained their proper character, the uppermost grains already
began to assume that character which in the third generation all
the grains acquired. As Ave do not know the aboriginal parent of
the maize, we cannot tell whether these changes are in any way
connected with reversion.

In the two following cases, reversion, as influenced by the po-
sition of the seed in the capsule, evidently acts. The Blue Imperial
pea is the offspring of the Blue Prussian, and has larger seed and
broader pods than its parent. Now Mr. Masters, of Canterbury, a
careful observer and a raiser of new varieties of the pea, states 2e
that the Blue Imperial always has a strong tendency to revert to
its parent-stock, and the reversion " occurs in this manner : the last
" (or uppermost) pea in the pod is frequently much smaller than the
" rest ; and if these small peas are carefully collected and sown
" separately, very many more, in proportion, will revert to their
" origin, than those taken from the other parts of the pod." Again
M. Chate27 says that in raising seedling stocks he succeeds in get-
ting eighty per cent, to bear double flowers, by leaving only a few
of the secondary branches to seed ; but in addition to this, " at the
" time of extracting the seeds, the upper portion of the pod is sepa-
" rated and placed aside, because it has been ascertained that the
" plants coming from the seeds situated in this portion of the pod,
" give eighty per cent, of single flowers." Now the production of
single-flowering plants from the seed of double-flowering plants is
clearly a case of reversion. These latter facts, as well as the con-
nection between a central position and pelorism and prolification,
show in an interesting manner how small a difference — namely a
little greater freedom in the flow of sap towards one part of the
same plant — determines important changes of structure.

Analogous or Parallel Variation. — By this term I wish
to express that similar characters occasionally make their
appearance in the several varieties or races descended
from the same species, and more rarely in the offspring
of widely distinct species. We are here concerned, not
as hitherto with the causes of variation, but with the
results ; but this discussion could not have been more
conveniently introduced elsewhere. The cases of ana-

58 ' Gardener's Chronicle,' 1850, p. 27 Quoted in ' Gardener's Cliron.,' 1866,

198. p. 1L

418 LAWS OF VAKIATION. Chap. XXVI.

logous variation, as far as their origin is concerned, may-
be grouped, disregarding minor subdivisions, under two
main heads ; firstly, those due to unknown causes having
acted on organic beings with nearly the same constitu-
tion, and which consequently vary in an analogous man-
ner; and secondly, those due to the reappearance of
characters which were possessed by a more or less remote
progenitor. But these two main divisions can often be
only conjecturally separated, and graduate, as we shall
presently see, into each other.

Under the first head of analogous variations, not due to reversion,
we have the many cases of trees belonging to quite different orders
which have produced pendulous and fastigate varieties. The
beech, hazel, and barberry have given rise to purple-leaved va-
rieties ; and as Bernhardi has remarked, * a multitude of plants, as
distinct as possible, have yielded varieties with deeply-cut or lacini-
ated leaves. Varieties descended from three distinct species of
Brassica have their stems, or so-called roots, enlarged into globular
masses. The nectarine is the offspring of the peach ; and the
varieties of both these trees dffer a remarkable parallelism in the
fruit being white, red, or yellow fleshed — in being clingstones or
freestones — in the flowers being large or small — in the leaves being
serrated or crenated, furnished with globose or reniform glands, or
quite destitute of glands. It should be remarked that each variety
of the nectarine has not derived its character from a corresponding
variety of the peach. The several varieties also of a closely allied
genus, namely the apricot, differ from each other in nearly the same
parallel manner. There is no reason to believe that in any of these
cases long-lost characters have reappeared, and in most of them this
certainly has not occurred.

Three species of Cucurbita have yielded a multitude of races,
which correspond so closely in character that, as Naudin insists,
they may be arranged in an almost strictly parallel series. Several
varieties of the melon are interesting from resembling in important
characters other species, either of the same genus or of alhed gen-
era ; thus, one variety has fruit so like, both externally and inter-
nally, the fruit of a perfectly distinct species, namely, the cucumber,
as hardly to be distinguished from it ; another has long cylindrical
fruit twisting about like a serpent ; in another the seeds adhere to

28 ' Ueber den Begriff der Pnanzenart,' 1834, 8. 14.

Chap. xxvi. ANALOGOUS VAKIATION. 419

portions of the pulp ; in another the fruit, when ripe, suddenly
cracks and falls into pieces ; and all these highly remarkable
peculiarities are characteristic of species belonging to allied gen-
era. We can hardly account for the appearance of so many un-
usual characters by reversion to a single ancient form ; but we
must believe that all the members of the family have inherited a
nearly similar constitution from an early progenitor. Our cereal
and many other plants offer similar cases.

With animals we have fewer cases of analogous variation, inde-
pendently of direct reversion. We see something of the kind in
the resemblance between the short-muzzled races of the dog, such
as the pug and bull-dog j in feather-footed races of the fowl, pigeon,
and canary-bird ; in horses of the most different races presenting
the same range of colour ; in all black-and-tan dogs having tan-
coloured eye-spots and feet, but in this latter case reversion may
possibly have played a part. Low has remarked29 that several
breeds of cattle are "sheeted," — that is, have a broad band of
white passing round their bodies like a sheet ; this character is
strongly inherited and sometimes originates from a cross ; it may
be the first step in reversion to an original or early type, for, as
was shown in the third chapter, white cattle with dark ears, feet,
and tip of tail formerly existed, and now exist in a feral or senii-
feral condition in several quarters of the world.

Under our second main division, namely, of analogous variations
due to reversion, the best cases are afforded by animals, and by
none better than by pigeons. In all the most distinct breeds sub-
varieties occasionally appear coloured exactly like the parent rock-
pigeon, with black wing-bars, white loins, banded tail, «Scc. ; and no
one can doubt that these characters are simply due to reversion.
So with minor details ; turbits properly have white tails, but occa-
sionally a bird is born with a dark-coloured and banded tail ; pout-
ers properly have white primary wing-feathers, but not rarely a
" sword-flighted" bird, that is, one with the few first primaries
dark-coloured, appears ; and in these cases we have characters
proper to the rock-pigeon, but new to the breed, evidently appear-
ing from reversion. In some domestic varieties the wing-bars, in-
stead of being simply black, as in the rock-pigeon, are beautifully
edged with different zones of colour, and they then present a strik-
ing analogy with the wing-bars in certain natural species of the
same family, such as Phapa chalcopt&ra; and this may probably be
accounted for by all the forms descended from the same remote
pregenitor having a tendency to vary in the same manner. Thus

:» ' Domesticated Animals,' 1S45, p. 351.

420 LAWS OF VARIATION. Chap. XXVI.

also we can perhaps understand the fact of some Laugher-pigeons
cooing almost like turtle-doves, and of several races having peculi-
arities in their night, for certain natural species (viz. C. torquatrix
and palumbus) display singular vagaries in this respect. In other
cases a race, instead of imitating in character a distinct species,
resemhles some other race ; thus certain runts tremble and slightly
elevate their tails, like fantails ; and turbits inflate the upper part
of their oesophagus, like pouter-pigeons.

It is a common circumstance to find certain coloured marks per-
sistently characterising all the species of a genus, but differing
much in tint ; and the same thing occurs with the varieties of the
pigeon : thus, instead of the general plumage being blue with the
wing-bars black, there are snow-white varieties with red bars, and
black varieties with white bars ; in other varieties the wing-bars, as
Ave have seen, are elegantly zoned with different tints. The Spot
pigeon is characterised by the whole plumage being white, except-
ing the tail and a spot on the forehead ; but these parts may be
red, yellow, or black. In the rock-pigeon and in many varieties the
tail is blue, with the outer edges of the outer feathers white ; but
in one sub-variety of the monk-pigeon we have a reversed varia-
tion, for the tail is white, except the outer edges of the outer feath-
ers, which are black.30

With some species of birds, for instance with gulls, certain co-
loured parts appear as if almost washed out, and I have observed
exactly the same appearance in the terminal dark tail-bar in cer-
tain pigeons, and in the whole plumage of certain varieties of the
duck. Analogous facts in the vegetable kingdom could be given.

Many Bub-varieties of the pigeon have reversed and somewhat
lengthened feathers on the back part of their heads, and this is
certainly not due to reversion to the parent-species, which shows
no trace of such structure ; but when we remember that sub-varie-
ties of the fowl, turkey, canary-bird, duck, and goose, all have top-
knots or reversed feathers on their heads ; and when we remember
that scarcely a single large natural group of birds can be named,
in which some members have not a tuft of feathers on their heads,
we may suspect that reversion to some extremely remote form has
come into action.

Several breeds of the fowl have either spangled or pencilled
feathers ; and these cannot be derived from the parent-species, the
Gallus bankiva ; though of course it is possible that an early pro-
genitor of this species may have been spangled, and a still earlier
or a later progenitor may have been pencilled. But as many galli

so Eechstein, 'Naturgeschichtc Deutschlands,' Band iv., 1795, s. 31.

Chap. XXVI. ANALOGOUS VARIATION. 421

naccous birds are spangled or pencilled, it is a niore probable view
that the several domestic breeds of the fowl have acquired this
kind of plumage from all the members of the family inheriting a
tendency to vary in a like manner. The same principle may ac-
count for the ewes in certain breeds of sheep being hornless, like
the females of some other hollow-horned ruminants; it may ac-
count for certain domestic cats having slightly-tufted ears, like
those of the lynx ; and for the skulls of domestic rabbits often
differing from each other in the same characters by which the
skulls of the various species of the genus Lepus differ.

I will only allude to one other case, already discussed. Now that we
know that the wild parent of the ass has striped legs, we may feel con-
fident that the occasional appearance of stripes on the legs of the do-
mestic ass is due to direct reversion ; but this will not account for the
lower end of the shoulder-stripe being sometimes angularly bent or
slightly forked. So, again, when we see dun and other coloured
horses with stripes on the spine, shoulders, and legs, we are led,
from reasons formerly given, to believe that they reappear from
direct reversion to the wild parent horse. But when horses have
t we or three shoulder-stripes with one of them occasionally forked
at the lower end, or when they have stripes on their faces, or as
foals are faintly striped over nearly their whole bodies, with the
stripes angularly bent one under the other on the forehead, or
irregularly branched in other parts, it would be rash to attribute
such diversified characters to the reappearance of those proper to
the aboriginal wild horse. As three African species of the genus
are much striped, and as we have seen that the crossing of the un-
striped species often leads to the hybrid offspring being conspicu-
ously striped — bearing also in mind that the act of crossing cer-
tainly causes the reappearance of long-lost characters — it is a more
probable view that the above-specified stripes are due to reversion,
not to the immediate wild parent-horse, but to the striped progeni-
tor of the whole genus.

I have discussed this subject of analogous variation at
considerable length, because, in a future work on natural
species, it will be shown that the varieties of one species
frequently mock distinct species — a fact in perfect har-
mony with the foregoing cases, and explicable only on
the theory of descent. Secondly, because these facts are
important from showing, as remarked in a former chap-
ter, that each trifling variation is governed by law, and is

422 LAWS OF VAEIATION. Chap. XXVI.

determined in a much higher degree by the nature of the
organisation, than "by the nature of the conditions to
which the varying being has been exposed. Thirdly, be-
cause these facts are to a certain extent related to a more
general law, namely, that which Mr. B. D. Walsh 31 has
called the " Law of Equable Variability" or, as he ex-
plains it, " if any given character is very variable in one
" species of a group, it will tend to be variable in allied
" species ; and if any given character is perfectly constant
" in one species of a group, it will tend to be constant in
" allied species."

This leads me to recall a discussion in the chapter on
Selection, in which it was shown that with domestic races,
which are now undergoing rapid improvement, those
parts or characters which are the most valued vary the
most. This naturally follows from recently selected
characters continually tending to revert to their former
less improved standard, and from their being still acted
on by the same agencies, whatever these may be, which
first caused the characters in question to vary. The same
principle is applicable to natural species, for, as stated
in my * Origin of Species,' generic characters are less
variable than specific characters ; and the latter are those
which have been modified by variation and natural selec-
tion, since the period when all the species belonging to
the same<genus branched off from a common progenitor,
whilst generic characters are those which have remained
unaltered from a much more remote epoch, and accord-
ingly are now less variable. This statement makes a
near approach to Mi*. Walsh's law of Equable Variabil-
ity. Secondary sexual characters, it may be added, rare-
ly serve to characterise distinct genera, for they usually
differ much in the species of the same genus, and are
highly variable in the individuals of the same species ;
we have also seen in the earlier chapters of this work how

31 ' Proc. Entomolog. Soe. of Philadelphia,' Oct, 1863, p. 213.

Chap. XXVI. SUMMARY. 423

variable secondary sexual characters become under do-
mestication.

Summary of the three previous Chapters, on the Laics of
Variation.

In the twenty-third chapter we have seen that changed
conditions occasionally act in a definite manner on the or-
ganisation, so that all, or nearly all, the individuals thus
exposed become modified in the same manner. But a
far more frequent result of changed conditions, whether
acting directly on the organisation or directly through
the reproductive system being affected, is indefinite and
fluctuating variability. In the three latter chapters we
have endeavored to trace some of the laws by which such
variability is regulated.

Increased use adds to the size of a muscle, together
with the blood-vessels, nerves, ligaments, the crests of
bone to which these are attached, the whole bone and
other connected bones. So it is with various glands. In-
creased functional activity strengthens the sense-organs.
Increased and intermittent pressure thickens the epider-
mis ; and a change in the nature of the food sometimes
modifies the coats of the stomach, and increases or de-
creases the length of the intestines. Continued disuse,
on the other hand, weakens and diminishes all parts of
the organisation. Animals which during many genera-
tions have taken but little exercise, have their lungs re-
duced in size, and as a consequence the bony fabric of
the chest, and the whole form of the body, become modi-
fied. With our anciently domesticated birds, the wings
have been little used, and they are slightly reduced ; with
their decrease, the crest of the sternum, the scapula?,
coracoids, and furcula, have all been reduced.

With domesticated animals, the reduction of a part
from disuse is never carried so far that a mere rudiment
is left, but we have c;ood reason to believe that this has

424 LAWS OF VARIATION. Chap. XXVL

often occurred under nature. The cause of this differ-
ence probably is that with domestic animals not only
sufficient time has not been granted for so profound a
change, but that, from not being exposed to a severe
struggle for life, the principle of the economy of organi-
sation does not come into action. On the contrary, we
sometimes see that structures which are rudimentary in
the parent-species become partially redeveloped in their
domesticated progeny. When rudiments are formed or
left under domestication, they are the result of a sudden
arrest of development, and not of long-continued disuse
with the absorption of all superfluous parts ; nevertheless
they are of interest, as showing that rudiments are the
relics of organs once perfectly developed.

Corporeal, periodical, and mental habits, though the
latter have been almost passed over in this work, become
changed under domestication, and the changes are often
inherited. Such changed habits in any organic being,
especially when living a free life, would often lead to the
augmented or diminished use of various organs, and con-
sequently to their modification. From long-continued
habit, and more especially from the occasional birth of
individuals with a slightly different constitution, domestic
animals and cultivated plants become to a certain extent
acclimatised, or adapted to a climate different from that
proper to the parent-species.

Through the principle of correlated variability, when
one part varies other parts vary, — either simultaneously,
or one after the other. Thus an organ modified during
an early embryonic period affects other parts subsequently
developed. When an organ, such as the beak, increases
or decreases in length, adjoining or correlated parts, as
the tongue and the orifice of the nostrils, tend to vary in
the same manner. When the whole body increases or
decreases in size, various parts become modified ; thus
with pigeons the ribs increase or decrease in number and
breadth. Homologous parts, which are identical during

Cuap. xxvi. SUMMARY. 425

their early development and are exposed to similar con-
ditions, tend to vary in the same or in some connected
manner, — as in the case of the right and left sides of the
body, of the front and hind limbs, and even of the head
and limbs. So it is with the organs of sight and hear-
ing; for instance, white cats with blue eyes are almost
always deaf. There is a manifest relation throughout the
body between the skin and its various appendages of hair,
feathers, hoofs, horns, and teeth. In Paraguay, horses
with curly hair have hoofs like those of a mule ; the
wool and the horns of sheep vary together; hairless
dogs are deficient in their teeth ; men with redundant hair
have abnormal teeth, either deficient or in excess. Birds
with long-winged feathers usually have long tail-feathers.
When long feathers grow from the outside of the legs
and toes of pigeons, the two outer toes are connected by
membrane ; for the whole leg tends to assume the struc-
ture of the wing. There is a manifest relation between
a crest of feathers on the head and a marvellous amount
of change in the skull of various fowls ; and in a lesser
degree, between the greatly elongated, lopping ears of
rabbits and the structure of their skulls. With plants the
leaves, various parts of the flower, and the fruit, often
vary together in a correlated manner.

In some cases Ave find correlation without being able
even to conjecture what is the nature of the connection, as
with various correlated monstrosities and diseases. This
is likewise iflie case with the colour of the adult pigeon, in
connection with the presence of down on the young bird.
Numerous curious instances have been given of peculiari-
ties of constitution, in correlation with colour, as shown
by the immunity of individuals of some one colour from
certain diseases, from the attacks of parasites, and from
the action of certain vegetable poisons.

Correlation is an important subject ; for with species,
and in a lesser degree with domestic races, we continually
find that certain parts have been greatly modified to

426 LAWS OF VAEIATION. Chap. XXVI.

serve some useful purpose ; but we almost invariably find
that other parts have likewise been more or less modi-
fied, without our being able to discover any advantage
in the change. No doubt great caution is necessary in
coming to this conclusion, for it is difficult to overrate
our ignorance on the use of various parts of the oi'gani-
sation ; but from what we have now seen, we may believe
that many modifications are of no direct service, having
arisen in correlation with other and useful changes.

Homologous parts during their early development
evince an affinity for each other, — that is, they tend to
cohere and fuse together much more readily than other
parts. This tendency to fusion explains a multitude of
normal structures. Multiple and homologous organs ai'e
especially liable to vary in number and probably in form.
As the supply of organised matter is not unlimited, the
principle of compensation sometimes comes into action ;
so that, when one part is greatly developed, adjoining
parts or functions are apt to be reduced ; but this prin-
ciple is probably of much less importance than the more
general one of the economy of growth. Through mere
mechanical pressure hard parts occasionally affect soft
adjoining parts. With plants the position of the flowers
on the axis, and of the seeds in the capsule, sometimes
leads, through a freer flow of sap, to changes of struc-
ture ; but these changes are often due to reversion. Mo-
difications, in whatever manner caused, will be to a cer-
tain extent regulated by that co-ordinating power or
nisus formativus, which is in fact a remnant of one of the
forms of reproduction, displayed by many lowly organ-
ised beings in their power of fissiparous generation and
budding. Finally, the effects of the laws, which directly
or indirectly govern variably, may be largely influenced
by man's selection, and will so far be determined by na-
tural selection that changes advantageous to any race
will be favoured and disadvantageous changes checked.

Domestic races descended from the same species, or

Ciup. xxvi. SUMMARY. 427

from two or moi"e allied species, are liable to revert to
characters derived from their common progenitor, and,
as they have much iiv common in their constitutions, they
are also liable under changed conditions to vary in the
same manner ; from these two causes analogous varieties
often arise. When we reflect on the several foregoing
laws, imperfectly as we understand them, and when we
bear in mind how much remains to be discovered, we
need not be surprised at the extremely intricate manner
in which our domestic productions have varied, and still
go on varying.

428 PROVISIONAL HYPOTHESIS Chap. XXYIL

CHAPTER XXVH.

PROVISIONAL HYPOTHESIS OF PANGENESIS.

PRELIMINARY REMARKS. — FIRST PART : — THE FACTS TO BE CON-
NECTED UNDER A SINGLE POINT OF VIEW, NAMELY, THE VARIOUS
KINDS OF REPRODUCTION — THE DIRECT ACTION OF THE MALE
ELEMENT ON THE FEMALE — DEVELOPMENT — THE FUNCTIONAL
INDEPENDENCE OF THE ELEMENTS OR UNITS OF THE BODY —
VARIABILITY — INHERITANCE — REVERSION.

SECOND PART : — STATEMENT OF THE HYPOTHESIS — HOW FAR THE
NECESSARY ASSUMPTIONS ARE IMPROBABLE — EXPLANATION BY
AID OF THE HYPOTHESIS O? THE SEVERAL CLASSES OF FACTS
SPECIFIED LN THE FIRST PART — CONCLUSION.

In the previous chapters large classes of facts, such as
those bearing on bud-variation, the various forms of in-
heritance, the causes and laws of variation, have been
discussed; and it is obvious that these subjects, as well
as the several modes of reproduction, stand in some sort
of relation to each other. I have been led, or rather
forced, to form a view which to a certain extent connects
these facts by a tangible method. Every one would
wTish to explain to himself, even in an imperfect manner,
how it is possible for a character possessed by some re-
mote ancestor suddenly to reappear in the offspring ; how
the effects of increased or decreased use of a limb can be
transmitted to the child ; how the male sexual element
can act not solely on the ovule, but occasionally on the
mother-form ; how a limb can be reproduced on the exact
line of amputation, with neither too much nor too little
added ; how the various modes of reproduction are con-
nected, and so forth. I am aware that my view is mere-

Chap. XXVir. OF PANGENESIS. 429

Iy a provisional hypothesis or speculation ; but until a
better one be advanced, it may be serviceable by bring-
ing together a multitude of facts which are at present
left disconnected by any efficient cause. As Whewell,
the historian of the inductive sciences, remarks : — " Ily-
" potheses may often be of service to science, when they
" involve a certain portion of incompleteness, and even
" of error." Under this point of view I venture to ad-
vance the hypothesis of Pangenesis, which implies that
the whole organisation, in the sense of every separate
atom or unit, reproduces itself. Hence ovules and pol-
len grains, — the fertilised seed or egg, as well as buds, —
include and consist of a multitude of germs thrown off
from each separate atom of the organism.

In the First Part I will enumerate as briefly as I can
the groups of facts which seem to demand connection ;
but certain subjects, not hitherto discussed, must be
treated at disproportionate length. In the Second Part
the hypothesis will be given ; and we shall see, after con-
sidering how far the necessary assumptions are in them-
selves improbable, whether it serves to bring under a
single point of view the various facts.

Part I.

Reproduction may be divided into two main classes,
namely, sexual and asexual. The latter is effected in
many ways — by gemmation, that is by the formation of
buds of various kinds, and by fissiparous generation, that
is by spontaneous or artificial division. It is notorious
that some of the lower animals, when cut into many
pieces, reproduce so many perfect individuals: Lyonnet
cut a Nais or freshwater worm into nearly forty pieces,
and these all reproduced perfect animals.1 It is probable
that segmentation could be carried much further in some

1 Quoted by Paget, ' Lectures on Pathology,' 1S53, p. 159.

430 PROVISIONAL HYPOTHESIS Chap. XXVII.

of the protozoa, and with some of the lowest plants each
cell will reproduce the parent-form. Johannes Miiller
thought that there was an important distinction between
gemmation and fission ; for in the latter case the divided
portion, however small, is more perfectly organised ; but
most physiologists are now convinced that the two pro-
cesses are essentially alike.3 Prof. Huxley remarks, " fis-
" sion is little more than a peculiar mode of budding,"
and Prof. H. J. Clark, who has especially attended to
this subject, shows in detail that there is sometimes " a
" compromise between self-division and budding." When
a limb is amputated, or when the whole body is bisected,
the cut extremities are said to bud forth ; and as the pa-
pilla, which is first formed, consists of undeveloped cellu-
lar.tissue like that forming an ordinary bud, the expres-
sion is apparently correct. We see the connection of the
two processes in another way ; for Trembley observed
that with the hydra the reproduction of the head after
amputation was checked as soon as the animal began to
bud.3

Between the production, by fissiparous generation, of
two or more complete individuals, and the repair of even
a very slight injury, we have, as remarked in a former
chapter, so perfect and insensible a gradation, that it is
impossible to doubt that they are connected processes.
Between the power which repairs a trifling injury in any
part, and the power which previously " was occupied in
" its maintenance by the continued mutation of its parti-
" cles," there cannot be any great difference ; and we may
follow Mr. Paget in believing them to be the self-same pow-

2 Dr. Lachmann, also, observes ('An- made between fission and budding is not

nals and Mag. of Nat. History,' 2nd series, a fundamental one. See Bonnet, 'CEu-

vol. xix., 1857, p. 231) with respect to vres d'Hist. Nat.,' torn, v., 1781, p. 839,

infusoria, that " fissation and gemma- for remarks on the budding-out of the

"tion pass into each other almost imper- amputated limbs of Salamanders. See,

" ceptibly." Again, Mr. W. C. Minor also, Professor Clark's work ' Mind in

(' Annals and Mag. of Nat. Hist.,' 3rd se- Nature,' New York, 1865, pp. 62, 94.
ries, vol. xi. p. 328) shows that with 3 Paget, ' Lectures on Pathology,' 1853,

Annelids the distinction that has been p. 158.

Chap. XXVII. OF PANGEKESIS. 431

er. As at each stage of growth an amputated part is replac-
ed by one in the same state of development, we must like-
wise follow Mr. Paget in admitting " that the powers of de-
" velopment from the embryo are identical with those exer-
cised for the restoration from injuries: in other words,
" that the powers are the same by which perfection is first
" achieved, and by which, when lost, it is recovered." 4
Finally, we may conclude that the several forms of gem-
mation, and of fissiparous generation, the repair of injuries,
the maintenance of each part in its proper state, and the
growth or progressive development of the whole structure
of the embryo, are all essentially the results of one and
the same great power.

Sexual Generation. — The union of the two sexual ele-
ments seems to make a broad distinction between sexual
and asexual reproduction. But the well-ascertained cases
of Parthenogenesis prove that the distinction is not really
so great as it at first appears ; for ovules occasionally,
and even in some cases frequently, become developed into
perfect beings, without the concourse of the male element.
J. Midler and others admit that ovules and buds have
the same essential nature. Certain bodies, which during
their early development cannot be distinguished by any
external character from true ovules, nevertheless must be
classed as buds, for though formed within the ovarium
they are incapable of fertilisation. This is the case with
the germ-balls of the Cecidomyide larvae, as described by
Leuckart.5 Ovules and the male element, before they be-
come united, have, like buds, an independent existence.*
Both have the power of transmitting every single charac-
ter possessed by the parent-form. "We see this clearly
Avhcn hybrids are paired inter se, for the characters of

« Paget, ' Lectures on Pathology,' 1S53, 1S66, pp. 167, 171.

pp. 152,164. • See some excellent remarks on this

8 On the Asexual Reproduction of head by Quatrefages, in ' Annales des

Cecydomyide Larvte, translated in Sc. Nat.,' Zoolog., 3rd series, 1S50, p.

' Annals and Mag. of Nat. Uist.,' March 18S.

432 PRO VISIONAL HYPOTHESIS Chap. XXVII.

either grandparent often reappear, either perfectly or by
segments, in the progeny. It is an error to suppose that
the male transmits certain characters and the female other
characters ; though no doubt, from unknown causes, one
sex sometimes has a sponger power of transmission than
the other.

It has been maintained by some authors that a bud dif-
fers essentially from a fertilised germ, by always repro-
ducing the perfect character of the parent-stock ; whilst
fertilised germs become developed into beings which dif-
fer, in a greater or less degree, from each other and from
their parents. But there is no such broad distinction as
this. In the eleventh chapter, numerous cases were given
showing that buds occasionally grow into plants hav-
ing new and strongly marked characters ; and varieties
thus produced can be propagated for a length of time by
buds, and occasionally by seed. Nevertheless, it must be
admitted that beings produced sexually are much more
liable to vary than those produced asexually ; and of this
fact a partial explanation will hereafter be attempted.
The variability in both cases is determined by the same
general causes, and is governed by the same laws. Hence
new varieties arising from buds cannot be distinguished
from those arising from seed. Although bud-varieties
usually retain their character during successive bud-gen-
erations, yet they occasionally revert, even after a long
series of bud-generations, to their former character. This
tendency to reversion in buds is one of the most remarka-
ble of the several points of agreement between the off-
spring from bud and seminal reproduction.

There is, however, one difference between beings pro-
duced sexually and asexually, which is very general. The
former usually pass in the course of their development
from a lower to a higher grade* as we see in the meta-
morphoses of insects and in the concealed metamorphoses
of the vertebrata ; but this passage from a lower to a
higher grade cannot be considered as a necessary accom-

Chap. XXVII. OF PANGENESIS. 433

paniment of sexual reproduction, for hardly anything of
the kind occurs in the development of Aphis amongst
insects, or with certain crustaceans, cephalopods, or with
any of the higher vascular plants. Animals propagated
asexually by buds or fission are on the other hand never
known to undergo a retrogressive metamorphosis; that
is, they do not first sink to a lower, before passing on to
their higher and final stage of development. But during
the act of asexual production or subsequently to it, they
often advance in organisation, as we see in the many
cases of " alternate generation." In thus sj)eaking of al-
ternate generation, I follow those naturalists who look at
the process as essentially one of internal budding or of
fissiparous generation. Some of the lower plants, how-
ever, such as mosses and certain algre, according to Dr.
L. Radlkofer,7 when propagated asexually, do undergo a
retrogressive metamorphosis. We can to a certain ex-
tent understand, as far as the final cause is concerned,
why beings propagated by buds should so rarely retro-
gress during development ; for with each organism the
structure acquired at each stage of development must be
adapted to its peculiar habits. Now, with beings pro-
duced by gemmation, — and this, differently from sexual
reproduction, may occur at am7 period of growth, — if
there were places for the support of many individuals at
some one stage of development, the simplest plan would
be that they should be multiplied by gemmation at that
stage, and not that they should first retrograde in their
development to an earlier or simpler structure, which
might not be fitted for the surrounding conditions.

From the several foregoing considerations we may con-
clude that the difference between sexual and asexual
generation is not nearly so great as it at first appears ;
and we have already seen that there is the closest agree-
ment between gemmation, fissiparous generation, the re-

7 • Annals and Mag. of Nat. Hist.,' 2nd series, vol. xx., 1S57, pp. 153-455.

434 PROVISIONAL HYPOTHESIS Chap. XXVII.

pair of injuries, and ordinary growth or development.
The capacity of fertilisation by the male element seems to
he the chief distinction between an ovule and a bud; and
this capacity is not invariably brought into action, as in
the cases of parthenogenetic reproduction. We are here
naturally led to inquire what the final cause can be of the
necessity in ordinary generation for the concourse of the
two sexual elements.

Seeds and ova are often highly serviceable as the means
of disseminating plants and animals, and of preserving
them during one or more seasons in a dormant state ; but
unimpregnated seeds or ova, and detached buds, would
be equally serviceable for both purposes. We can, how-
ever, indicate two important advantages gained by the
concourse of the two sexes, or rather of two individuals
belonging to opposite sexes ; for, as I have shown in a
former chapter, the structure of every organism appears
to be especially adapted for the concurrence, at least oc-
casionally, of two individuals. In nearly the same man-
ner as it is admitted by naturalists that hybridism, from
inducing sterility, is of service in keeping the forms of
life distinct and fitted for their proper places ; so, when
species are rendered highly variable by changed conditions
of life, the free intercrossing of the varying individuals
will tend to keep each form fitted for its proper plaee in
nature ; and crossing can be effected only by sexual gen-
eration, but whether the end thus gained is of sufficient
importance to account for the first origin of sexual inter-
course is very doubtful. Secondly, I have shown, from
the consideration of a large body of facts, that, as a slight
change in the conditions of life is beneficial to each crea-
ture, so, in an analogous manner, is the change effected in
the germ by sexual union with a distinct individual ; and
I have been led, from observing the many widely-extend-
ed provisions throughout nature for this purpose, and
from the greater vigour of crossed organisms of all kinds,
as proved by direct experiments, as well as from the evil

Chap. XXVII. OF PANGENESIS. 435

effects of close interbreeding when long continued, to be-
lieve that the advantage thus gained is very great. Be-
sides these two important ends, there may, of course, be
others, as yet unknown to us, gained by the concourse of
the two sexes.

Why the germ, which before impregnation undergoes
a certain amount of development, ceases to progress and
perishes, unless it be acted on by the male element ; and
why conversely the male element, which is enabled to
keep alive for even four or five years within the sperma-
theca of a female insect, likewise perishes, unless it acts
on or unites with the germ, are questions which cannot
be answered with any certainty. It is, however, possible
that both sexual elements perish, unless brought into
union, simply from including too little formative matter
for independent existence and development ; for certainly
they do not in ordinary cases differ in their power of
giving character to the embryo. This view of the im-
portance of the quantity of formative matter seems proba-
ble from the following considerations. There is no reason
to suspect that the spermatozoa or pollen-grains of the
same individual animal or plant differ from each other ;
yet Quatrefages has shown in the case of the Teredo,8 as
did formerly Prevost and Dumas with other animals,
that more than one spermatozoon is requisite to fertilise
an ovule. This has likewise been clearly proved by New-
port,9 who adds the important fact, established by numer-
ous experiments, that, when a very small number of
spermatozoa are applied to the ova of Batrachians, they
are only partially impregnated and the embryo is never
fully developed : the first step, however, towards devel-
opment, namely, the partial segmentation of the yelk,
does occur to a greater or less extent, but is never com-
pleted up to granulation. The rate of the segmentation

8 'Annates des Sc. Nat.,' 3d series, 8 'Transact. Phil. Soc.,' 1S51, pp. 19G,

1850, torn. xiii. 20S, 210 ; 1853, p. 245, 247.

436 PROVISIONAL HYPOTHESIS Chap. XXVII.

is likewise determined by the number of the spermatozoa.
With respect to plants, nearly the same results were ob-
tained by Kolreuter and Gartner. This last careful
observer found,10 after making successive trials on a Malva
with more and more pollen-grains, that even thirty grains
did not fertilise a single seed ; but when forty grains
were applied to the stigma, a few seeds of small size were
formed. The pollen-grains of Mirabilis are extraordina-
rily large, and the ovarium contains only a single ovule ;
and these circumstances led Naudin" to make the fol-
lowing interesting experiments : a flower was fertilised
by three grains and succeeded perfectly ; twelve flowers
were fertilised by two grains, and seventeen flowers by a
single grain, and of these one flower alone in each lot
perfected its seed ; and it deserves especial notice that
the plants produced by these two seeds never attained
their proper dimensions, and bore flowers of remarkably
small size. From these facts we clearly see that the
quantity of the peculiar formative matter which is con-
tained within the spermatozoa and pollen-grains is an all-
important element in the act of fertilisation, not only in
the full development of the seed, but in the vigour of the
plant produced from such seed. We see something of
the same kind in certain cases of parthenogenesis, that is,
when the male element is wholly excluded ; for M. Jour-
dan " found that, out of about 58,000 eggs laid by unim-
pregnated silk-moths, many passed through their early
embryonic stages, showing that they were capable of self-
development, but only twenty-nine out of the whole num-
ber produced caterpillars. Therefore it is not an improba-
ble view that deficient bulk or quantity in the formative
matter, contained within the sexual elements, is the main
cause of their not having the capacity of prolonged
separate existence and development. The belief that it

10 ' Beitrage zur Kenntniss,' &c, 1S44, torn. i. p. 27.

B. 345. 12 A3 quoted by Sir J. Lubbock in

11 ' Nouvelles Archives du Museum,' 'Nat. Hist. Review,' 1S62, p. 345.

Chap. XXVII. OF PANGENESIS. 437

is the function of the spermatozoa to communicate life to
the ovule seems a strange one, seeing that the unimpreg-
nated ovule is already alive and continues for a consider-
able time alive. We shall hereafter see that it is probable
that the sexual elements, or possibly only the female
element, include certain primordial cells, that is, such as
have undergone no differentiation, and which are not
present in an active state in buds.

Graft-hybrids. — When discussing in the eleventh chap-
ter the curious case of the Cytisus adami, facts were
given which render it to a certain degree probable, in ac-
cordance with the belief of some distinguished botanists,
that, when the tissues of two plants belonging to distinct
species or varieties are intimately united, buds are after-
wards occasionally produced which, like hybrids, com-
bine the characters of the two united forms. It is certain
that when trees with variegated leaves are grafted or
budded on a common stock, the latter sometimes produces
buds bearing variegated leaves ; but this may perhaps be
looked at as a case of inoculated disease. Should it ever
be proved that hybridised buds can be formed by the
union of two distinct vegetative tissues, the essential
identity of sexual and asexual reproduction would be
shown in the most interesting manner ; for the power of
combining in the offspring the characters of both parents,
is the most striking of all the functions of sexual genera-
tion.

Direct Action of the Male Element on the Female. — In
the chapter just referred to, I have given abundant proofs
that foreign pollen occasionally affects the mother- plant
in a direct manner. Thus, when Gallesio fertilised an
orange-flower with jiollen from the lemon, the fruit bore
stripes of perfectly characterised lemon-peel : with peas,
several observers have seen the colour of the seed-coats
and even of the pod directly affected by the pollen of a
distinct variety ; so it has been with the fruit of the apple,
which consists of the modified calyx and upper part of

438 PROVISIONAL HYPOTHESIS Chap. XXVII.

the flower-stalk. These parts in ordinary cases are wholly
formed by the mother-plant. We here see the male ele-
ment affecting and hybridising not that part which it is
properly adapted to affect, namely the ovule, but the
partially developed tissues of a distinct individual. We
are thus brought half-way towards a graft-hybrid, in
which the cellular tissue of one form, instead of its pollen,
is believed to hybridise the tissues of a distinct foirni. I
formerly assigned reasons for rejecting the belief that the
mother-plant is affected through the intervention of the
hybridised embryo ; but even if this view were admitted,
the case would become one of graft-hybridism, for the
fertilised embryo and the mothei'-plant must be looked at
as distinct individuals.

With animals which do not breed until nearly mature,
and of which all the pai'ts are then fully developed, it is
hardly possible that the male element should directly
affect the female. But we have the analogous and per-
fectly well-ascertained case of the male element of a dis-
tinct form, as with the quagga and Lord Morton's mare,
affecting the ovarium of the female, so that the ovules
and offspring subsequently produced by her when impreg-
nated by other males are plainly affected and hybridised
by the first male.

Development. — The fertilised germ reaches maturity by
a vast number of changes : these are either slight and
slowly effected, as when the child grows into the man, or
are great and sudden, as with the metamorphoses of most
insects. Between these extremes we have, even within
the same class, every gradation : thus, as Sir J. Lubbock
has shown,13 there is an Ephemerous insect which moults
above twenty times, undergoing each time a slight but
decided change of structure ; and these changes, as he
further remarks, probably reveal to us the normal stages
of development which are concealed and hurried through,

13 ' Transact. Linn. Soc.,' vol. xxiv., 1863, p. i

Chap. XWII. OF PANGENESIS. 439

or suppressed, in most other insects. In ordinary meta-
morphoses, the parts and organs appear to become chang-
ed into the corresponding parts in the next stage of de-
velopment ; but there is another form of development,
which has been called by Professor Owen metagenesis.
In this case " the new parts are not moulded upon the
" inner surface of the old ones. The plastic force has
" changed its course of operation. The outer case, and
" all that gave form and character to the precedent indi-
"vidual, perish and are cast oft*; they are not changed
" into the corresponding parts of the neAV individual.
" These are due to a new and distinct developmental pro-
" cess," &c.14 Metamorphosis, however, graduates so in-
sensibly into metagenesis, that the two processes cannot
be distinctly separated. For instance, in the last change
which Cirripedes undergo, the alimentary canal and some
other organs are moulded on pre-existing pai'ts ; but the
eyes of the old and the young animal are developed in en-
tirely different parts of the body; the tips of the mature
limbs are formed within the larval limbs, and may be said
to be metamorphosed from them ; but their basal portions
and the whole thorax are developed in a plane actually at
right angles to the limbs and thorax of the larva ; and
this may be called metagenesis. The metagenetic pro-
cess is carried to an extreme degree in the development
of some Echinoderms, for the animal in the second stage
of development is formed almost like a bud within the
animal of the first stage, the latter being then cast off like
an old vestment, yet sometimes still maintaining for a
short period an independent vitality.15

If, instead of a single individual, several were to be
thus developed metagenetically within a pre-existing form,

14 ' Parthenogenesis,' 1^49, pp. 25-26. ously metamorphosis jrraduates into, srem-

Prof. Huxley has some excellent re- mation or zoid-formation, which is in fact

marks (' Medical Times,' 1856. p. 637) on the same as metagenesis,

this subject, in reference to the develop- 15 Prof. J. Reay Greene, in Gunther's

ment of star-fishes, and shows how curi- ' Record of Zoolog. Lit.,' 1865, p. 625.

440 PROVISIONAL HYPOTHESIS Chap. XXVII.

the process would be called one of alternate generation.
The young thus developed may either closely resemble
the encasing parent-form, as with the larvae of Cecido-
myia, or may differ to an astonishing degree, as with
many parasitic worms and with jelly-fishes ; but this
does not make any essential difference in the process, any
more than the greatness or abruptness of .the change in
the metamorphoses of insects.

The whole question of development is of great import-
ance for our present subject. When an organ, the eye
for iustance, is metagenetically formed in a part of the
body where, during the previous stage of development
no eye existed, Ave must look at it as a new and indepen-
dent growth. The absolute independence of new and old
structures, which correspond in structure and function,
is still more obvious when several individuals are formed
within a previous encasing form, as in the cases of alter-
nate generation. The same important principle probably
comes largely into play even in the case of continuous
growth, as we shall see when we consider the inherit-
ance of modifications at corresponding ages.

We are led to the same conclusion, namely, the inde-
pendence of parts successively developed, by another and
quite distinct group of facts. It is well known that many
animals belonging to the same class, and therefore not
differing widely from each other, pass through an ex-
tremely different course of development. Thus certain
beetles, not in any way remarkably different from others
of the same order, undergo what has been called a hyper-
metamorphosis — that is, they pass through an early stage
wholly different from the ordinary grub-like lava. In the
same sub-order of crabs, namely, the Macroura, as Fritz
Miiller remarks, the river cray-fish is hatched under the
same form which it ever afterwards retains ; the young
lobster has divided legs, like a Mysis ; the Pala?mon ap-
pears under the form of a Zoea, and Peneus under the
JSTauplius-form ; and how wonderfully these larval forms

Chap. XXVIL OF PANGENESIS. 441

differ from each other, is known to every naturalist. ie
Some other crustaceans, as the same author observes, start
from the same point and arrive at nearly the same end,
but in the middle of their development are widely differ-
ent from each other. Still more striking cases could be
given with respect to the Echinodermata. With the
Medusa? or jelly-fishes Professor Allman observes, " the
" classification of the Hydroida would be a comparatively
" simple task if, as has been erroneously asserted, gene-
" rically-identical medusoids always arose from generi-
" cally-identical polypoids ; and on the other hand, that
" generically-identical polypoids always gave origin to
" generically-identical medusoids." So, again, Dr. Stre-
thill Wright remarks, " in the lifediistory of the Hy-
" droidae any phase, planuloid, polypoid, or medusoid,
" may be absent." 17

According to the belief now generally accepted by our
best naturalists, all the members of the same order or
class, the Macrourous crustaceans for instance, are de-
scended from a common progenitor. During their descent
they have diverged much in structure, but have i*etained
much in common ; and this divergence and retention of
character has been effected, though they have passed and
still pass through marvellously different metamorphoses.
This fact well illustrates how independent each structure
must be from that which precedes and follows it in the
course of development.

The Functional Independence of the Elements or Units
of the Body. — Physiologists agree that the whole organism
consists of a multitude of elemental parts, which are to a
great extent independent of each other. Each organ,

14 Fritz Muller's ' Fur Darwin,' ISM, allied genera.
b. 65. 71. The highest authority on crus- I7 Prof. Al'man, in 'Annals and Mag.
taceans. Prof. Milne Edwards, insists of Nat. Hist,' 3rd series, vol. xiii., 1S64,
(' Annal. des Sci. Nat.,' 2nd series, p. 34S ; Dr. S. Wright, idem, vol. viii.,
Zoolog., torn. iii. p. 322) on their meta- 1S61, p. 127. See also p. 35S for ana-
morphoses differing even in closely logous statements by Sars.

442 PROVISIONAL HYPOTHESIS Chap. XXVII.

says Claude Bernard,18 has its proper life, its autonomy ;
it can develop and reproduce itself independently of the
adjoining tissues. The great German authority, Vir-
chow,19 asserts still more emphatically that each system,
as the nervous or osseous system, or the blood, consists

of an " enormous mass of minute centres of action

" Every element has its own special action, and even
" though it derive its stimulus to activity from other
" parts, yet alone effects the actual performance of its

" duties Every single epithelial and muscular

" fibre-cell leads a sort of parasitical existence in relation

" to the rest of the body Every single bone-

" corpuscle really possesses conditions of nutrition pecu-
" liar to itself." Each element, as Mr. Paget remarks,
lives its appointed time and then dies, and after being
cast off or absorbed, is replaced.20 I presume that no
physiologist doubts that, for instance, each bone-cor-
puscle of the finger differs from the corresponding cor-
puscle in the corresponding joint of the toe; and there
can hardly be a doubt that even those on the correspond-
ing sides of the body differ, though almost identical in
nature. This near approach to identity is curiously
shown in many diseases in which the same exact points on
the right and left sides of the body are similarly affected ;
thus Mr. Paget 21 gives a drawing of a diseased pelvis, in
which the bone has grown into a most complicated
pattern, but "there is not one spot or line on one
" side which is not represented, as exactly as it would
be in a mirror, on the other."

Many facts support this view of the independent life
of each minute element of the body. Virchow insists
that a single bone-corpuscle or a single cell in the skin
may become diseased. The spur of a cock, after being
inserted into the eye of an ox, lived for eight years, and

18 ' Tissus Yivants,' 1866, p. 22. 20 Paget, ' Surgical Pathology,' vol. i.,

« ' Cellular Pathology,' translat. by 1853, pp. 12-14.
Dr. Chance, 1SG0, pp. 14, 18, S3, 4C0. 21 Idem, p. 19.

Chap. XXVII. OF PANGENESIS. 443

acquired a weight of 306 grammes, or nearly fourteen
ounces." The tail of a pig has heen grafted into the
middle of its back, and reacquired sensibility. Dr. Oilier 23
inserted a piece of periosteum from the bone of a young
dog under the skin of a rabbit, and true bone was devel-
oped. A multitude of similar facts could be given. The
frequent presence of hairs and of perfectly developed teeth,
even teeth of the second dentition, in ovarian tumours,"
are facts leading to the same conclusion.

Whether each of the innumerable autonomous elements
of the body is a cell or the modified product of a cell, is
a more doubtful question, even if so wide a definition be
given to the term, as to include cell-like bodies without
walls and without nuclei.25 Professor Lionel Beale uses
the term "germinal matter" for the contents of cells,
taken in this wide acceptation, and he draws a broad
distinction between germinal matter and " formed ma-
terial- " or the various products of cells.28 But the doc-
trine of omnis cellula e cellula is admitted for plants,
and is a widely prevalent belief with respect to animals.27
Thus Virchow, the great supporter of the cellular theory,
whilst allowing that difficulties exist, maintains that
every atom of tissue is derived from cells, and these from
pre-existing cells, and these primarily from the egg,
which he regards as a great cell. That cells, still retain'
ing the same nature, increase by self-division or prolifer-
ation, is admitted by almost every one. But when an
organism undergoes a great change of structure during
development, the cells, which at each stage are supposed
to be directly derived from previously-existing cells,

23 Mantegazza, quoted in ' Popular of cells, see Ernst Hackel's ' Generelle

Science Review,' July 1S65, p. 522. Morpholog.,' Band ii., 1866, s. 2T5. •

23 ' De la Production Artiflcielle des a6 ' The Structure and Growth of

Os,' p. 8. Tissue?.' 1R65, p. 21, Ac.

34 Isidore Geoffroy St. nilaire, ' Hist. " Dr. W. Turner, ■ The present As-

des Anomalies,' torn. ii. pp. 549, 560, pect of Cellular Pathology,' ' Edinburgh

662 ; Virchow, idem, p. 4S4. Medical Journal,' April, 1863.

-5 For the most recent classification

444 PROVISIONAL HYPOTHESIS Chap. XXVII.

must likewise be greatly changed in nature ; this change
is apparently attributed by the supporters of the cellular
doctrine to some inherent power which the cells possess,
and not to any external agency.

Another school maintains that cells and tissues of all
kinds may be formed, independently of pre-existing cells,
from plastic lymph or blastema ; and this it is thought is
well exhibited in the repair of wounds. As I have not
especially attended to histology, it would be presumptuous
in me to express an opinion on the two opposed doctrines.
But every one appears to admit that the body consists
of a multitude of " organic units," 28 each of which pos-
sesses its own proper attributes, and is to a certain extent
independent of all others. Hence it will be convenient
to use indifferently the terms cells or organic units or
simply units.

Variability and Inheritance. — We have seen in the
twenty-second chapter that variability is not a principle
co-ordinate with life or reproduction, but results from
special causes, generally from changed conditions acting
during successive generations. Part of the fluctuating
variability thus induced is apparently due to the sexual
system being easily affected by changed conditions, so
that it is often rendered impotent ; and when not so
seriously affected, it often fails in its proper function of
transmitting truly the characters of the parents to the
offspring. But variability is not necessarily connected
with the sexual system, as we see from the cases of bud-
variation ; and although we may not be able to trace the
nature of the connexion, it is probable that many devia-
tions of structure which appear in sexual offspring result
from changed conditions acting directly on the organisa-
tion, independently of the reproductive organs. In some

28 This term is used by Dr. E. Mont- other cells by a process of growth, but

Romery (' On the Formation of so-called believes that they originate through

Cells in Animal Bodies,' 1S67, p. 42), certain chemical changes,
who denies that cell.? are derived from

Chap. XXVIL OF PANGENESIS. 445

instances we may feel sure of this, when all, or nearly-
all the individuals which have been similarly exposed are
similarly and definitely affected — as in the dwarfed and
otherwise changed maize brought from hot counti'ies
when cultivated in Germany ; in the change of the fleece
in sheep within the tropics ; to a certain extent in the
increased size and early maturity of our highly-improved
domesticated animals ; in inherited gout from intemper-
ance; and in many other such cases. Now, as such
changed conditions do not especially affect the reproduc-
tive organs, it seems mysterious on any ordinary view
why their product, the new organic being, should be
similarly affected.

How, again, can we explain to ourselves the inherited
effects of the use or disuse of particular organs ? The
domesticated duck flies less and walks more than the
wild duck, and its limb-bones have become in a corre-
sponding manner diminished and increased in comparison
with those of the wild duck. A horse is trained to cer-
tain paces, and the colt inherits similar consensual move-
ments. The domesticated rabbit becomes tame from
close confinement; the dog intelligent from associating
with man ; the retriever is taught to fetch and carry ;
and these mental endowments and bodily powers are all
inherited. Nothing in the whole circuit of physiology is
more wonderful. How can the use or disuse of a parti-
cular limb or of the brain affect a small aggregate of l'e-
pi-oductive cells, seated in a distant part of the body, in
such a manner that the being developed from these cells
inherits the characters of either one or both parents ?
Even an imperfect answer to this question would be
satisfactory.

Sexual reproduction does not essentially differ, as we
have seen, from budding or self-division, and these pro-
cesses graduate through the repair of injuries into ordi-
nary development and growth ; it might therefore be
expected that every character would be as regularly

446 PKO VISIONAL HYPOTHESIS Chap. XXVII.

transmitted by all the methods of reproduction as by-
continued growth. In the chapters devoted to inheritance
it was shown that a multitude of newly-acquired charac-
ters, whether injurious or beneficial, whether of the
lowest or highest vital importance, are often faithfully
transmitted — frequently even when one parent alone
possesses some new peculiarity. It deserves especial
attention that characters appearing at any age tend to
reappear at a corresponding age. We may on the
whole conclude that in all cases inheritance is the rule,
and non-inheritance the anomaly. In some instances a
character is not inherited, from the conditions of life
being directly opposed to its development ; in many in-
stances, from the conditions incessantly inducing fresh
variability, as with grafted fruit-trees and highly culti-
vated flowers. In the remaining cases the failure may be
attributed to reversion, by which the child resembles its
grandparents or more remote progenitors, instead of its
parents.

This principle of Reversion is the most wonderful of
all the attributes of Inheritance. It proves to us that
the transmission of a character and its development,
which ordinarily go together and thus escape discrimina-
tion, are distinct powers ; and these powers in some
cases are even antagonistic, for each acts alternately in
successive generations. Reversion is not a rare event,
depending on some unusual or favourable combination
or circumstances, but occurs so regularly with crossed
animals and plants, and so frequently with uncrossed
breeds, that it is evidently an essential part of the prin-
ciple of inheritance. We know that changed conditions
have the power of evoking long-lost characters, as in
the case of some feral animals. The act of crossing in
itself possesses this power in a high degree. What can
be more wonderful than that characters, which have dis-
appeared during scores, or hundreds, or even thousands
of generations, should suddenly reappear perfectly devel-

Chap. XXVIL OF PANGENESIS. 447

oped, as in the case of pigeons and fowls when purely
bred, and especially when crossed ; or as with the zebrine
stripes on dun-coloured horses, and other such cases ?
Many monstrosities come under this same head, as when
rudimentary organs are redeveloped, or when an organ
which we must believe was possessed by an early proge-
nitor, but of which not even a rudiment is left, suddenly
reappears, as with the fifth stamen in some Scrophulari-
aceoe. We have already seen that reversion acts in bud-
reproduction ; and we know that it occasionally acts
during the gi'owth of the same individual animal, especi-
ally, but not exclusively, when of crossed parentage, — as
in the rare cases described of individual fowls, pigeons,
cattle, and rabbits, which have reverted as they advanced
in years to the colours of one of their parents or ancestors.
We are led to believe, as formerly explained, that every
character which occasionally reappears is present in a
latent form in each generation, in nearly the same manner
as in male and female animals secondary characters of the
opposite sex lie latent, ready to be evolved when the re-
productive organs are injured. This comparison of the
secondary sexual characters which are latent in both
sexes, with other latent characters, is the more appro-
priate from the case recorded of the Hen, which assumed
some of the masculine characters, not of her own race,
but of an early progenitor ; she thus exhibited at the same
time the redevelopment of latent characters of both kinds
and connected both classes. In every living creature we
may feel assured that a host of lost characters lie ready
to be evolved under proper conditions. How can we
make intelligible, and connect with other facts, this won-
derful and common capacity of reversion, — this power of
calling back to life loner-lost characters ?

448 PKOVISIOISrAL HYPOTHESIS Chap. XXVII.

Part II.

I have now enumerated the -chief facts which every one
would desire to connect by some intelligible bond. This
can be done, as it seems to me, if we make the following
assumptions ; if the first and chief one be not rejected,
the others, from being supported by various physiological
considerations, will not appear very improbable. It is
almost universally admitted that cells, or the units of the
body, propagate themselves by self-division or prolifera-
tion, retaining the same nature, and ultimately becoming
converted into the various tissues and substances of the
body. But besides this means of increase I assume that
cells, before their conversion into completely passive or
"form-material," throw off minute granules or atoms,
which circulate freely throughout the system, and when
supplied with proper nutriment multiply by self-division,
subsequently becoming developed into cells like those from
which they were derived. These granules for the sake
of distinctness may be called cell-gemmules, or, as the
cellular theory is not fully established, sinrply gemmules.
They are supposed to be transmitted from the parents to
the offspring, and are generally developed in the genera-
tion which immediately succeeds, but are often trans-
mitted in a dormant state during many generations and
are then developed. Their development is supposed to
depend on their union with other partially developed
cells or gemmules which precede them in the regular
course of growth. Why I use the term union, will be
seen when we discuss the direct action of pollen on the
tissues of the mother-plant. Gemmules are supposed to
be thrown off by every cell or unit, not only during the
adult state, but during all the stages of development.
Lastly, I assume that the gemmules in their dormant
state have a mutual affinity for each other, leading to
their aggregation either into buds or into the sexual ele-

Chap. XXVII.

OF PANGENESIS.

449

raents. Hence, speaking strictly, it is not the reproduc-
tive elements, nor the buds, which generate new organ-
isms, but the cells themselves throughout the body.
These assumptions constitute the provisional hypothesis
which I have called Pangenesis. Nearly similar views
have been propounded, as I find, by other authors, more
especially'by Mr. Herbert Spencer;29 but they are here
modified and amplified.

29 Prof. Huxley has called my atten-
tion to the views of Buffon and Bonnet.
The former ('Hist. Nat. Gen.,' edit, of
1749, torn. ii. pp. 54, 62, 329, 333, 420,
425) supposes that organic molecules ex-
ist in the food consumed by every living
creature ; and that these molecules are
analogous in nature with the various
organs by which they are absorbed.
When the organs thus become fully de-
veloped, the molecules being no longer
required collect and form buds or the
sexual elements. If Buffon had assumed
that his organic molecules had been
formed by each separate unit through-
out the body, his view and mine would
have been closely similar.

Bonnet (' CEuvres d'Hist. Nat,' torn,
v., part i., 1781, 4to edit., p. 334) speaks
of the limbs having germs adapted for
the reparation of all possible losses ; but
whether these germs are supposed to be
the same with those within the buds and
sexual organs is not clear. His famous
but now exploded theory of embo':t< m, n I,
implies that perfect germs are included
within germs in endless succession, pre-
formed and ready for all succeeding ge-
nerations. According to my view, the
germs or gemmules of each separate part
were not originally pre-formed, but are
continually produced at all ages during
each generation, with some handed down
from preceding generations.

Prof. Owen remarks (' Parthenogene-
sis,' 1849, pp. 5-8), " Not all the progeny
" of the primary impregnated germ-cell
" are required for the formation of the
" body in all animals : certain of the de-
" rivative germ-cells may remain un-
" changed and become included in that

" body which has been composed of their
" metamorphosed and diversely com-
" bined or confluent brethren : so includ-
" ed, any derivative germ-cell, or the
" nucleus of such, may commence and
" repeat the same processes of growth by
" imbibition, and of propagation by spon-
" taneous fission, as those to which itself
" owed its origin ;" &c. By the agency
of these germ-cells Prof. Owen accounts
for parthenogenesis, for propagation by
self-division during successive genera-
tions, and for the repairs of injuries.
His view agrees with mine in the as-
sumed transmission and multiplication
of his germ-cells, but differs fundamen-
tally from mine in the belief that the
primary germ-cell was formed within the
ovarium of the female and was ferti-
lised by the male. My gemmules are
supposed to be formed, quite indepen-
dently of sexual concourse, by each sepa-
rate cell or unit throughout the body,
and to be merely aggregated within the
reproductive organs.

Lastly, Mr. Herbert Spencer (' Princi-
ples of Biology,' vol. i., 1863-4, chaps, iv.
and viii.) has discussed at considerable
length what he designates as physiologi-
cal units. These agree with my gem-
mules in being supposed to multiply and
to be transmitted from parent to child ;
the sexual elements are supposed to
serve merely as their vehicles ; they are
the efficient agents in all the forms of re-
production and in the repairs of injuries ;
they account for inheritance, but they
are not brought to bear on reversion or
atavism, and this is unintelligible tome;
they are supposed to possess polarity,
or, as I call it, affinity ; and apparently

450 PROVISIONAL HYPOTHESIS Chap, xxvii.

Before proceeding to show, firstly, how far these as-
sumptions are in themselves probable, and secondly, how
far they connect and explain the various groups of facts
with which we are concerned, it may be useful to give an
illustration of the hypothesis. If one of the simplest
Protozoa be formed, as appears under the microscope, of
a small mass of homogeneous gelatinous matter* a minute
atom thrown off from any part and nourished under fa-
vourable circumstances would naturally reproduce the
whole ; but if the upper and lower surfaces were to differ
in texture from the central portion, then all three parts
would have to throw off atoms or gemmules, which
when aggregated by mutual affinity would form either
buds or the sexual elements. Precisely the same view
may be extended to one of the higher animals ; although
in this case many thousand gemmules must be thrown
off from the various parts of the body. Now, when the
leg, for instance, of a salamander is cut off, a slight crust
forms over the wound, and beneath this crust the unin-

they are believed to be derived from "part similarly changed in form. In-
each separate part of the whole body. " deed, when treating of Adaptation, we
But gemmules differ from Mr. Spencer's " saw that an organ modified by increase
physiological units, inasmuch as a cer- " or decrease of function can but slowly
tain number, or mass of them, are, as " so react on the system at large as to
we shall see, requisite for the develop- " bring about those correlative changes
ment of each cell or part. Nevertheless " required to produce a new equilibrium ;
I should have concluded that Mr. Spen- " and yet only when such new equilibri-
cer's views were fundamentally the same " um has been established, can we ex-
with mine, had it not been for several " pect it to be fully expressed in the
passages which, as far as I understand " modified physiological units of which
them, indicate something quite different. "the organism is built — only then can
I will quote some of these passages from " we count on a complete transfer of the

pp. 254-256. "In the fertilised germ "modification to descendants."

" we have two groups of physiological " That the change in the offspring must,

" units, slightly different in their struc- " other things equal, be in the same di-

" tuve." ... . " It is not obvious " rection as the change in the parent, we

"that change in the form of the part, "may dimly see is implied by the fact,

" caused by changed action, Involves " that the change propagated throughout

" such change in the physiological units " the parental system is a change to-

" throughout the organism, that these, "wards a new state of equilibrium — a

" when groups of them arc thrown off in " change tending to bring the actions of

" the shape of reproductive centres, will "all organs, reproductive included, into

"unfold into organisms that have this "harmony with these new actions."

Cuap. XXVII. OF PANGENESIS. 451

jured cells or units of bone, muscle, nerves, &c, are sup-
posed to unite with the diffused gemmules of those cells
which in the perfect leg come next in order ; and these
as they become slightly developed unite with others, and
so on until a papilla of soft cellular tissue, the "budding
leg," is formed, and in time a perfect leg.30 Thus, that
portion of the leg which had been cut off, neither more
nor less, Avould be reproduced. If the tail or leg of a
young animal had been cut off, a young tail or leg would
have been reproduced, as actually occurs with the ampu-
tated tail of the tadpole ; for gemmules of all the units
which compose the tail are diffused throughout the body
at all ages. But during the adult state the gemmules of
the larval tail would remain dormant, for they would not
meet with pre-existing cells in a proper state of develop-
ment with which to unite. If from changed conditions
or any other cause any part of the body should become
permanently modified, the gemmules, which are merely
minute portions of the contents of the cells forming the
part, would naturally reproduce the same modification.
But gemmules previously derived from the same part
before it had undergone any change, would still be dif-
fused throughout the organisation, and would be transmit-
ted from generation to generation, so that under favour-
able circumstances they might be redeveloped, and then
the new modification would be for a time or for ever lost.
The aggregation of gemmules derived from every part
of the body, through their mutual affinity, would form
buds, and their aggregation in some special manner, ap-
parently in small quantity, together probably with the

30 M. Philipeaux (' Comptes Rendus,' mals the whole body may be bisected and

Oct. 1, 1866, p. 576, and June, 1S67) has both halves be reproduced, this belief

lately shown that when the entire fore- does not seem probable. May not the

limb, including the scapula, is extirpated, early closing of a deep wound, as in the

the power of regrowth is lost. From this case of the extirpation of the scapula,

he concludes that it is necessary for re- prevent the formation or protrusion of

growth that a small portion of the limb the nascent limb ?
should be left. But as in the lower ani-

452 PRO VISIONAL HYPOTHESIS Chap. XXVII.

presence of gemmules of certain primordial cells, would
constitute the sexual elements. By means of these illus-
trations the hypothesis of pangenesis has, I hope, been
rendered intelligible.

Physiologists maintain, as we have seen, that each cell,
though to a large extent dependent on others, is like-
wise, to a certain extent, independent or autonomous. I
go one small step further, and assume that each cell
casts off a free gemmule, which is capable of reproducing
a similar cell. There is some analogy between this view
and what we see in compound animals and in the flow-
er-buds on the same tree ; for these are distinct indivi-
duals capable of true or seminal reproduction, yet have
parts in common and are dependent on each other ; thus
the tree has its bark and trunk, and certain corals, as the
Virgularia, have not only parts, but movements in com-
mon.

The existence of free gemmules is a gratuitous as-
sumption, yet can hardly be considered as very improb-
able, seeing that cells have the power of multiplication
through the self-division of their contents. Gemmules
differ from true ovules or buds inasmuch as they are
supposed to be capable of multiplication in their unde-
veloped state. No one probably will object to this
capacity as improbable. The blastema within the egg
has been known to divide and give birth to two embryos ;
and Thuret 31 has seen the zoospore of an alga divide itself,
and both halves germinate. An atom of small-pox mat-
ter, so minute as to be borne by the wind, must multiply
itself many thousand-fold in a person thus inoculated.32
It has recently been ascertained 33 that a minute portion

si 'Annal. des Sc. Nat.,' 3rd series, 9th, 1865, pp. 273, 880.

Bot., torn, xiv., 1850, p. 244. 33 Third Report of the R. Comm. on

32 See some very interesting papers the Cattle Plague, as quoted in ' Gard.

on this subject by Prof. Lionel Beale, Chronicle,' 18C6, p. 446.
in 'Medical Times and Gazette,' Sept.

Chap. XXVII. OF PANGENESIS. 453

of the mucous discharge from an animal affected with
rinderpest, if placed in the blood of a healthy ox, in-
creases so fast that in a short space of time " the whole
" mass of blood, weighing many pounds, is infected, and
M every small particle of that blood contains enough
" poison to give, within less than forty-eight hours, the
" disease to another animal."

The retention of free and undeveloped gemmules in
the same body from early youth to old age may appear
improbable, but we should remember how long seeds lie
dormant in the earth and buds in the bark of a tree.
Their transmission from generation to generation may
appear still more improbable ; but here again we should
remember that many rudimentary and useless organs
are transmitted and have been transmitted during an
indefinite number of generations. We shall presently
see how well the long-continued transmission of unde-
veloped gemmules explains many facts.

As each unit, or group of similar units throughout the
body, casts off its gemmules, and as all are contained
within the smallest egg or seed, and within each sper-
matozoon or pollen-grain, their number and minuteness
must be something inconceivable. I shall hereafter re-
Cur to this objection, which at first appears so formida-
ble ; but it may here be remarked that a cod-fish has
been found to produce 4,872,000 eggs, a single Ascaris
about 64,000,000 eggs, and a single Orchidaceous plant
probably as many million seeds.34 In these several cases,

3* In a cod-fish, weighing 20 lb., Mr. Acropera, and found the number to be

P. Buckland (' Land and Water,' 1S67, 871,250. Now this plant produces sev-

p. 57) calculated the above number of eral flowers on a raceme and many ra-

eggs. In another instance, Ilarmer cemes during a season. In an allied

('Phil. Transact.,' 1767, p. 280) found genus, Gongora, Mr. Scott has seen

3,G>1,700 eggs. For the Ascaris, see Car- twenty capsules produced on a single

penter's ' Comp. Phys.,' 1S54, p. 590. Mr. raceme : ten such racemes on the Ac;o-

J. Scott, of the Royal Botanic Garden of pera would yield above seventy-four

Edinburgh, calculated, in the same man- millions of seed. I may add that Fritz

ner as I have done for some British Mfdler informs me that he found in a

orchids ('Fertilisation of Orchids,' p. 344), capsule of a Maxillaria, in South Brazil,

the number of seeds in a capsule of an that the seed weighed 42>£ grains : he

454 PROVISIONAL HYPOTHESIS Chap. XXVII.

the spermatozoa and pollen-grains must exist in con-
siderably larger numbers. Now, when we have to deal
with numbers such as these, which the human intellect
cannot grasp, there is no good reason for rejecting our
present hypothesis on account of the assumed existence
of cell-gemmules a few thousand times more numerous.

The gemmules in each organism most be thoroughly
diffused ; nor does this seem improbable considering
their minuteness, and the steady circulation of fluids
throughout the body. So it must be with the gemmules
of plants, for with certain kinds even a minute frag-
ment of a leaf will reproduce the whole. But a difficulty
here occurs ; it would appear that with plants, and prob-
ably with compound animals, such as corals, the gem-
mules do not spread from bud to bud, but only through
the tissues developed from each separate bud. "We are
led to this conclusion from the stock being rarely affected
by the insertion of a bud or graft from a distinct variety.
This non-diffusion of the gemmules is still more plainly
shown in the case of ferns ; for Mr. Bridgman35 has prov-
ed that, when spores (which it should be remembered are
of the nature of buds) are taken from a monstrous part of
a frond, and others from an ordinary part, each reproduces
the form of the part whence derived. But this non-diffu-
sion of the gemmules from bud to bud may be only ap-
parent, depending, as we shall hereafter see, on the na-
ture of the first-formed cells in the buds.

The assumed elective affinity of each gemmule for that
particular cell which precedes it in the order of develop-
ment is supported by many analogies. In all ordinary
cases of sexual reproduction the male and female elements
have a mutual affinity for each other : thus, it is believed

then arranged half a grain of seed in a same plant sometimes produces balf-a-

narrow line, and by counting a measured dozen capsules.

length found the number in the half-grain S5 'Annals and Mag. of Nat. Hist.,'

to be 20,667, so that in the capsule there 3rd series, vol. viii., 1861, p. 490.
must have been 1,756,440 seeds ! The

Chap. XXVII. OF PANGENESIS. 455

that about ten thousand species of Composite exist, and
there can be no doubt that if the pollen of all these spe-
cies could be, simultaneously or successively, placed on
the stigma of any one species, this one would elect with
unerring certainty its own pollen. This elective capacity
is all the more wonderful, as it must have been acquired
since the many species of this great group of plants
branched off from a common progenitor. On any view
of the nature of sexual reproduction, the protoplasm con-
tained within the ovules and within the sperm-cells (or
the " spermatic force" of the latter, if so vague a term be
preferred) must act on each other by some law of special
affinity, either during or subsequently to impregnation,
so that corresponding parts alone affect each other ; thus,
a calf produced from a short-horned cow by along-horned
bull has its horns and not its- horny hoofs affected by the
union of the two forms, and the offspring from two birds
with differently coloured tails have their tails and not
their whole plumage affected.

The various tissues of the body plainly show, as many
physiologists have insisted,30 an affinity for special orga-
nic substances, whether natural or foreign to the body.
We see this in the cells of the kidneys attracting urea
from the blood : in the worrara poison affecting the
nerves ; upas and digitalis the muscles ; the Lytta vesi-
catoria the kidneys ; andin the poisonous matter of many
diseases, as small-pox, scarlet-fever, hooping-cough, glan-
ders, cancer, and hydrophobia, affecting certain definite
parts of the body or certain tissues or glands.

The affinity of various parts of the body for each other
during their early development was shown in the last
chapter, when discussing the tendency to fusion in homo-
logous parts. This affinity displays itself in the normal
fusion of organs which are separate at an early embryonic

36 Paget, 'Lectures on Pathology,' 294; Claude Bernard, ' Des Tissus
p. 'JT ; VJrcbcnr, ' Cellular Pathology,' Vivants,' pp. 177, 210, 337 ; M filler's
translat. by Dr. Chance, pp. 123, 126, ' Physiology,' Eng. translat., p. 290.

456 PRO VISIONAL HYPOTHESIS Chap. XXVII.

age, and still more plainly in those marvellous cases of
double monsters in which each bone, muscle, vessel, and
nerve in the one embryo, blends with the corresponding
part in the other. The affinity between homologous or-
gans may come into action with single parts, or with the
entire individual, as in the case of flowers or fruits which
are symmetrically blended together with all their parts
doubled, but without any other trace of fusion.

It has also been assumed that the development of each
gemmule depends on its union with another cell or unit
which has just commenced its development, and which,
from preceding it in order of growth, is of a somewhat
different nature. Nor is it a very improbable assumption
that the development of a gemmule is determined by its
union with a cell slightly different in nature, for abundant
evidence was given in the seventeenth chapter, showing
that a slight degree of differentiation in the male and
female sexual elements favours in a marked manner their
union and subsequent development. But what determines
the development of the gemmules of the first-formed or
primordial cell in the unimpregnated ovule, is beyond
conjecture.

It must also be admitted that analogy fails to guide us
towards any determination on several other points : for
instance, whether cells, derived from the same parent-
cell, may, in the regular course of growth, become de-
veloped into different structures, from absorbing peculiar
kinds of nutriment, independently of their union with
distinct gemmules. We shall appreciate this difficulty if
we call to mind, what complex yet symmetrical growths
the cells of plants yield when they are inoculated by the
poison of a gall-insect. With animals various polypoid
excrescences and tumours are now generally admitted"
to be the direct product, through proliferation, of normal

87 Virchow, ' Cellular Pathology,' trans, by Dr. Chance, 1S60, pp. 60, 1C2, 245, 441,
454.

Chip. XXVII. OF PANGENESIS. 457

cells which have become abnormal. In the regular growth
and repair of bones, the tissues undergo, as Virchow re-
marks,38 a whole series of permutations and substitutions.
" The cartilage-cells may be converted by a direct trans-
" formation into marrow-cells, and continue as such ; or
"they may first be converted into osseous and then into-
" medullary tissue ; or lastly, they may first be converted
" into marrow and then into bone. So variable are the
" permutations of these tissues, in themselves so nearly
"allied, and yet in their external appearance so com-
" pletely distinct." But as these tissues thus change their
nature at any age, without any obvious change in their
nutrition, we must suppose in accordance with our hypo-
thesis that gemmules derived from one kind of tissue com-
bine with the cells of another kind, and cause t'he succes-
sive modifications.

It is useless to speculate at what period of develop-
ment each organic unit casts off its gemmules ; for the
whole subject of the development of the various ele-
mental tissues is as yet involved in much doubt. Some
physiologists, for instance, maintain that muscle or nerve-
fibres are developed from cells, which are afterwards
nourished by their own proper powers of absorption ;
whilst other physiologists deny their cellular origin ; and
Beale maintains that such fibres are renovated exclusively
by the conversion of fresh germinal matter (that is the
so-called nuclei) into " formed material." However this
may be, it appears probable that all external agen-
cies, such as changed nutrition, increased use or disuse-
&c, which induced any permanent modification in a
structure, would at the same time or previously act on
the cells, nuclei, germinal or formative matter, from
which the structures in question were developed, and
consequently would act on the gemmules or cast-off

atom3.

—

™ Idem, pp. 412-126

458 PKO VISIONAL HYPOTHESIS Chap. XXVII.

There is another point on which it is useless to specu-
late, namely, whether all gemmules are free and sepa-
rate, or whether some are from the first united into small
aggregates. A feather, for instance, is a complex struc-
ture, and, as each separate part is liable to inherited va-
riations, I conclude that each feather certainly generates
a large number of gemmules ; but it is possible that these
may be aggregated into a compound gemmule. The
same remark applies to the petals of a flower, which in
some cases are highly complex, with each ridge and
hollow contrived for special purposes, so that each part
must have been separately modified, and the modifica-
tions transmitted ; consequently, separate gemmules, ac-
cording to our hypothesis, must have been thrown off
from each cell or part. But, as we sometimes see half
an anther or a small portion of a filament becoming pe-
taliform, or parts or mere stripes of the calyx assuming
the colour and texture of the corolla, it is probable that
Avith petals the gemmules of each cell are not aggregated
together into a compound gemmule, but are freely and
separately diffused.

Having now endeavoured to show that the sevei'al fore-
going assumptions are to a certain extent supported by
analogous facts, and having discussed some of the most
doubtful points, we will consider how far the hypothesis
brings under a single point of view the various cases enu-
merated in the First Part. All the forms of reproduc-
tion graduate into each other and agree in'their product ;
for it is impossible to distinguish between organisms
produced from buds, from self-division, or from fertilised
germs ; such organisms are liable to variations of the
same nature and to reversion of character ; and as we now
see that all the forms of reproduction depend on the ag-
gregation of gemmules derived from the whole body, we
can understand this general agreement. It is satisfactory
to find that sexual and asexual generation, by both of
which widely different processes the same living crea-

Chap. XXVII. OF PANGENESIS. 459

ture is habitually produced, are fundamentally the same.
Parthenogenesis is no longer wonderful ; in fact, the won-
der is that it should not oftener occur. We see that the
reproductive organs do not actually create the sexual ele-
ments ; they merely determine or permit the aggregation
of the gemmules in a special manner. These organs, to-
gether with their accessory parts, have, however, high
functions to perform ; they give to both elements a spe-
cial affinity for each other, independently of the contents
of the male and female cells, as is shown in the case of
plants by the mutual "reaction of the stigma and pollen-
grains ; they adapt one or both elements for independent
temporary existence, and for mutual union. The contri-
vances for these purposes are sometimes Avonderfully com-
plex, as with the spermatophores of the Cephalopoda.
The male elemeut sometimes possesses attributes which,
if observed in an independent animal, would be put down
to instinct guided by sense-organs, as when the spermato-
zoon of an insect finds its way into the minute micropyle
of the egg, or as when the antherozoids of certain algae
swim by the aid of their cilia? to the female plant, and
force themselves a minute orifice. In these latter cases,
however, we must not believe that the male element has
acquired its powers, on the same principle with the larvse
of animals, namely by successive modifications developed
at corresponding periods of life : we can hardly avoid in
these cases looking at the male element as a sort of pre-
mature larva, which unites, or, like one of the lower algae,
conjugates, with the female element. What determines
the aggregation of the gemmules within the sexual organs
we do not in the least know ; nor do we know why buds
are formed in certain definite places, leading to the sym-
metrical growth of trees and corals, nor why adventitious
buds may be formed almost anywhere, even on a petal,
and frequently upon healed wounds.3' As soon as the

33 See Rev. J. M. Berkeley, in ' Gard. veloped on the petal of the Clarkia, See
Chron.,' April 23th, 1866, on a bud de- also H. Schacht, 'Lehrbuch der Anat,,'

460 PROVISIONAL HYPOTHESIS Chap. XXVII.

geraraules have aggregated themselves, development ap-
parently commences, but in the case of buds is often
afterwards suspended, and in the case of the sexual ele-
ments soon ceases, unless the elements of the opposite
sexes combine ; even after this has occurred, the fertilised
germ, as with seeds buried in the ground, may remain
during a lengthened period in a dormant state.

The antagonism which has long been observed,40 though
exceptions occur,41 between active growth and the power
of sexual reproduction — between the repair of injuries and
gemmation — and with plants, between rapid increase by
buds, rhizomes, &c, and the production of seed, is partly
explained by the gemmules not existing in sufficient num-
bers for both processes. But this explanation hardly ap-
plies to those plants which naturally produce a multitude
of seeds, but which, through a comparatively small in-
crease in the number of the buds on their rhizomes or off-
sets, yield few or no seed. As, however, we shall pre-
sently see that buds probably include tissue which has al-
ready been to a certain extent developed or differentiated,
some additional organised matter will thus have been ex-
pended.

From one of the forms of Reproduction, namely, spon-
taneous self-division, we are led by insensible steps to the
repair of the slightest injury; 'and the existence of gem-
mules, derived from every cell or unit throughout the
body and everywhere diffused, explains all such cases, —

4c, 1S59, Theile ii. 8. 12, on adventitious reprcductioa. Ernst Hackel has re-
buds, cently (' Monatsbericht Akad. Wiss. Ber-

40 Mr. Herbert Spencer (' Principles of lin,' Feb. 2nd, 1S65) observed the sur-
Biology,' vol. ii. p. 430) has fully dis- prising case1 of a medusa, with its repro-
cussed the antagonism between growth ductive organs active, which produces
and reproduction. . by budding a widely different form of

41 The male salmon is known to breed medusa; and this latter also has the
at a very early age. The Triton and power of sexual reproduction. Krohn
Siredon, whilst retaining their larval has shown (' Annals and Mag. of Nat.
branchiae, according to Filippi and Du- Hist.,' 3rd series, vol. xix., 1862, p. 6)
meril (' Annals and Mag. of Nat. Hist.,' that certain other medusae, whilst sex-
8rd series, 1866, p. 157), are capable of ually mature, propagate by gemmae.

Chap. XXVII. ■ OF * PANGENESIS. 461

even the "wonderful fact that, -when the limbs of the sala-
mander were cut off many times successively by Spallan-
zani and Bonnet, they were exactly and completely re-
produced. I have heard this process compared with the
recrystallisation which occurs when the angles of a broken
crystal are repaired ; and the two processes have this much
in common, that in one case the polarity of the molecules
is the efficient cause, and in the other the affinity of the
gemmules for particular nascent cells.

Pangenesis does not throw much light on Hybridism,
but agrees well with most of the ascertained facts. We
may conclude from the fact of a single spermatozoon or
pollen-grain being sufficient for impregnation, that a cer-
tain number of gemmules derived from each cell or unit
are required for tjie development of each part. From the
occurrence of parthenogenesis, more especially in the case
of the silk-moth, in which the embryo is often partially
formed, we may also infer that the female element in-
cludes nearly sufficient gemmules of all kinds for indepen-
dent development, so that when united with the male
element the gemmules must be superabundant. Now, as
a general rule, when two species or races are crossed re-
ciprocally, the offspring do not differ, and this shows that
both sexual elements agree in power, in accordance with
the view that they include the same gemmules. Hybrids
and mongrels are generally intermediate in character be-
tween the two parent-forms, yet occasionally they closely
resemble one parent in one part and the other parent in
another part, or even in their whole structure : nor is this
difficult to understand on the admission that the gem-
mules in the fertilised germ are superabundant in number,
aud that those derived from one parent have some advan-
tage in number, affinity, or vigour over those derived
from the other parent. Crossed forms sometimes exhibit
the colour or other characters of either parent in stripes
or blotches ; and this may occur in the first generation,
or through reversion in succeeding bud and seminal gen-

462 PBO VISIONAL HYPOTHESIS Ohap. XXVII.

erations, as in the several instances given in the eleventh
chapter. In these cases we must follow Naudin," and
admit that the " essence" or " element" of the two species,
which terms I should translate into the gemmules, have
an affinity for their own kind, and thus separate them-
selves into distinct stripes or blotches ; and reasons were
given, when discussing in the fifteenth chapter the incom-
patibility of certain characters to unite, for believing in
such mutual affinity. When two forms are crossed, one
is not rarely found to be prepotent in the transmission of
character over the other ; and this we cart explain only
by again assuming that the one form has some advantage
in the number, vigour, or affinity of its gemmules, except
in those cases, where certain characters are present in the
one form and latent in the other. For instance, there is
a latent tendency in all pigeons to become blue, and, when
a blue pigeon is crossed with one of any other colour, the
blue tint is generally prepotent. When we consider la-
tent characters, the explanation of this form of prepotency
will be obvious.

When one species is crossed with another it is notorious
that they do not yield the full or proper number of off-
spring; and we can only say on this head that, as the
development of each organism depends on such nicely-
balanced affinities between a host of gemmules and de-
veloping cells or units, we need not feel at all surprised
that the commixture of gemmules derived from two dis-
tinct species should lead to a partial or complete failure
of development. With respect to the sterility of hybrids
produced from the union of two distinct species, it was
shown in the nineteenth chapter that this depends exclu-
sively on the reproductive organs being specially affected ;
but why these organs should be thus affected we do not
know, any more than why unnatural conditions of life,

48 See his excellent discussion on this subject in ' Nouvelles Archives du Museum,'
torn. i. p. 151.

Chap. XXVii. OF PANGENESIS. 463

though compatible with health, should cause sterility ; or
why continued close interbreeding, or the illegitimate
unions of dimorphic and trimorphic plants, induce the
same result. The conclusion that the reproductive organs
alone are affected, and not the whole organisation, agrees
perfectly with the unimpaired or even increased capacity
in hybrid plants for propagation by buds ; for this implies;
according to our hypothesis, that the cells of the hybrids
throw oft' hybridised cell-gemmules, which become aggre-
gated into buds, but fail to become aggregated within
the reproductive organs, so as to form the sexual elements.
In a similar manner many plants, when placed under un-
natural conditions, fail to produce seed, but can readily
he propagated by buds. We shall presently see that pan-
genesis agrees well with the strong tendency to rever-
sion exhibited by all crossed animals and plants.

It was shown in the discussion on graft-hybrids that
there is some reason to believe that portions of cellular
tissue taken from distinct plants become so intimately
united, as afterwards occasionally to produce crossed or
hybridised buds. If this fact were fully established, it
would, by the aid of our hypothesis, connect gemmation
and sexual reproduction in the closest manner.

Abundant evidence has heen advanced proving that
pollen taken from one species or variety and applied to
the stigma of another sometimes dii*ectly aflects the tis-
sues of the mother-plant. It is probable that this occurs
with many plants during fertilisation, but can only be
detected when distinct forms are crossed. On any ordi-
nary theory of reproduction this is a most anomalous cir-
cumstance, for the pollen-grains are manifestly adapted to
act on the ovule, but in these cases they act on the colour,
texture, and form of the coats of the seeds, on the ovarium
itself, which is a modified leaf, and even on the calyx
and upper part of the flower-peduncle. In accordance
with the hypothesis of pangenesis pollen includes gem-
mules, derived from every part of the organisation, which

464 PROVISIONAL HYPOTHESIS Chap. XXVII.

diffuse themselves and multiply by self-division ; hence it
is not surprising that gemmules within the pollen, which
are derived from the parts near the reproductive organs,
should sometimes be able to affect the same parts, whilst
still undergoing development, in the mother-plant.

As, during all the stages of development, the tissues of
plants consist of cells, and as new cells are not known to
be formed between, or independently of, pre-existing cells,
we must conclude that the gemmules derived from the
foreign pollen do not become developed merely in con-
tact with pre-existing cells, but actually peneti*ate the
nascent cells of the mother-plant. This process may be
compared with the ordinary act of fertilisation, during
which the contents of the pollen-tubes penetrate the
closed embryonic sack within the ovule, and determine
the development of the embryo. According to this view,
the cells of the mother-plant may almost literally be said
to be fertilised by the gemmules derived from the foreign
pollen. "With all organisms, as we shall presently see, the
cells of organic units of the embryo during the successive
stages or development may in like manner be said to be
fertilised by the gemmules of the cells, which come next
in the order of formation.

Animals, when capable of sexual reproduction, are fully
developed, and it is scarcely possible that the male ele-
ment should affect the tissues of the mother in the same
direct manner as with plants ; nevertheless it is certain
that her ovaria are sometimes affected by a previous im-
pregnation, so that the ovules subsequently fertilised by a
distinct male are plainly influenced in character ; and
this, as in the case of foreign pollen, is intelligible
through the diffusion, retention, and action of the gem-
mules included within the spermatozoa of the previous
male.

Each organism reaches maturity through a longer or
shorter course of development. The changes may be
small and insensibly slow, as when a child grows into a

Chap. XXVIL OF PANGENESIS. 465

man, or many, abrupt, and slight, as in the metamor-
phoses of certain ephemerous insects, or again few and
strongly marked, as with most other insects. Each part
may be moulded within a previously existing and corre-
sponding part, and in this case it will appear, falsely as I
believe, to be formed from the old part ; or it may be de-
veloped within a wholly distinct part of the body, as in
the extreme cases of metagenesis. An eye, for instance,
may be developed at a spot whei'e no eye previously ex-
isted. "We have also seen that allied organic beings in
the course of their metamorphoses sometimes attain near-
ly the same structure after passing through widely differ-
ent forms ; or conversely, after passing through nearly
the same early forms, arrive at a widely different termi-
nation. In these cases it is very difficult to believe that
the early cells or units possess the inherent power, inde-
pendently of any external agent, of producing new struc-
tures wholly different in form, position, and function.
But these cases become plain on the hypothesis of pange-
nesis. The organic units, during each stage of develop-
ment, throw off gemmules, which, multiplying, are trans-
mitted to the offspring. In the offspring, as soon as any
particular cell or unit in the proper order of development
becomes partially developed, it unites with (or to speak
metaphorically is fertilised by) the gemmule of the next
succeeding cell, and so onwards. Now, supposing that
at any stage of development, certain cells or aggregates
of cells had been slightly modified by the action of some
disturbing cause, the cast-off gemmules or atoms of the
cell-contents could hardly fail to be similarly affected, and
consequently would reproduce the same modification.
This process might be repeated until the structure of the
part at this particular stage of development became great-
ly changed, but this would not necessarily affect other
parts whether previously or subsequently developed. In
this manner we can understand the remarkable indepen-
dence of structure in the successive metamorphoses, and

466 PROVISIONAL HYPOTHESIS Chap. XXVII.

especially in the successive mutageneses of many ani-
mals.

The term growth ought strictly to be confined to mere
increase of size, and development to change of structure.43
Now, a child is said to grow into a man, and a foal into
a horse, hut, as in these cases there is much change of struc-
ture, the process properly belongs to the order of devel-
opment. We have indirect evidence of this in many va-
riations and diseases supervening during so-called growth
at a particular period, and being* inherited at a corre-
sponding period. In the case, however, of diseases which
supervene during old age, subsequently to the ordinary
period of procreation, and which nevertheless are some-
times inherited, as occurs with brain and heart complaints,
we must suppose that the organs were in fact affected at
an earlier age and threw off at this period affected gem-
mules ; but that the affection became visible or injurious
only after the prolonged growth of the part in the strict
sense of the word. In all the changes of structure which
regularly supervene during old age, we see the effects of
deteriorated growth, and not of true development.

In the so-called process of alternate generation many
individuals are generated asexually during very early or
later stages of development. These individuals may
closely resemble the preceding larval form, but generally
are wonderfully dissimilar. To understand this process
we must suppose that at a certain stage of development
the gemmules are multiplied at an unusual rate, and be-
come aggregated by mutual affinity at many centres of
attraction, or buds. These bads, it may be remarked,
must include gemmules not only of all the succeeding but
likewise of all the preceding stages of development ; for
when mature they have the power of transmitting by
sexual generation gemmules of all the stages, however

43 Various physiologists have insisted stance in microcephalous idiots, in

on this distinction between growth and which the brain continues to grow after

development. Prof. Marshall (' Phil. having been arrested in its development.
Transact.,' 1SW, p. 544) gives a good in-

Chap, xxvii. OF PANGENESIS. 467

numerous these may be. It was shown in the First Part,
at least in regard to animals, that tlie new beings which
are thus at any period asexually generated do not retro-
grade in development — that is, they do not pass through
those earlier stages, through which the fertilised germ of
the same animal has to pass ; and an explanation of this
fact was attempted as far as the final or teleological cause
is concerned. We can likewise understand the proximate
cause, if we assume, and the assumption is far from im-
probable, that buds, like chopped-up fragments of a hydra,
are formed of tissue which has already passed through
several of the earlier stages of development ; for in this
case their component cells or units would not unite with
the gemmules derived from the earlier-formed cells, but
only with those which came next in the order of develop-
ment. On the other hand, we must believe that, in the
sexual elements, or probably in the female alone, gem-
mules of certain primordial cells are present ; and these,
as soon as their development commences, unite in due
succession with the gemmules of every part of the body,
from the first to the last period of life.

The principle of the independent formation of each part,
in so far as its development depends on the union of
the pi'oper gemmules with certain nascent cells, together
with the superabundance of the gemmules derived from
both parents and self-multiplied, throws light on a widely
different group of facts, which on any ordinary view of
development appears very strange. I allude to organs
which ai'e abnormally multiplied or transposed. Thus
gold-fish often have supernumerary fins placed on various
parts of their bodies. We have seen that, when the tail
of a lizard is broken off, a double tail is sometimes repro-
duced, and when the foot of the salamander is divided
longitudinally, additional digits are occasionally formed.
When frogs, toads, &c, are born with their limbs doubled,
as sometimes occurs, the doubling, as Gervais remarks,"

<« ' Comptc Rendu,' Nov. 14, 1SW, p. SOO.

468 * PKOVISIONAL HYPOTHESIS Chap. XXVII.

cannot be due to the complete fusion of two embryos,
with the exception of the limbs, for the larvae are limb-
Jess. The same argument is applicable45 to certain in-
sects produced with multiple legs or antennae, for these
are metamorphosed from apodal or antennseless larvae.
Alphonse Milne-Edwards 46 has described the curious case
of a crustacean in which one eye-peduncle supported, in-
stead of a complete eye, only an imperfect cornea, out of
the centre of which a portion of an antenna was devel-
oped. A case has been recorded 47 of a man who had
during both dentitions a double tooth in place of the left
second incisor, and he inherited this peculiarity from his
paternal grandfather. Several cases are known48 of ad-
ditional teeth having been developed in the palate, more
especially with horses, and in the orbit of the eye. Cer-
tain breeds of sheep bear a whole crowd of horns on their
foreheads. Hairs occasionally appear in strange situa-
tions, as within the ears of the Siamese hairy family \ and
hairs "quite natural in structure" have been observed
" within the substance of the brain." 49 As many as five
spurs have been seen on both legs in certain Game-fowls.
In •'the Polish fowl the male is ornamented with a top-
knot of hackles like those on his neck, whilst the female
has one of common feathers. In feather-footed pigeons
and fowls, feathers like those on the wing arise from the
outer side of the legs and toes. Even the elemental parts
of the same feather may be transposed; for in tli£ Sebas-
topol goose, barbules are developed on the divided fila-
ments of the shaft.

Analogous cases are of such frequent occurrence with
plants that they do not strike us with sufficient surprise.

44 As previously remarked by Quatre- view,' April 1863, p. 454.

fages, in his ' Metamorphoses de 48 Isid. Geoffroy St. Hilaire, ' Hist, (lea

l'Homme,' &c, 1S62, p. 129. Anomalies,' torn, i., 1832, pp. 435, 657;

46 Gunther's ' Zoological Record,' 1S64, and torn. ii. p. 560.

p. 279. 49 Virchow, ' Cellular Pathology,' 1860,

47 Sedgwick, in ' Medico-Chirug. Re- p. 66.

Chap. XXVII. OF PANGENESIS. 469

Supernumerary petals, stamens, and pistils, are often pro-
duced. I have seen a leaflet low down in the compound
leaf of Vicia sativa converted into a tendril, and a ten-
dril possesses many peculiar properties, such as sponta-
neous movement and irritability. The calyx sometimes
assumes, either wholly or by stripes, the colour and tex-
ture of the corolla. Stamens are so frequently converted,
more or less completely, into petals, that such cases are
passed over as not deserving notice ; but as petals have
special functions to perform, namely, to protect the in-
cluded organs, to attract insects, and in not a few cases to
guide their entrance by well-adapted contrivances, we
can hardly account for the conversion of stamens into
petals merely by unnatural or superfluous nourishment.
Again, the edge of a petal may occasionally be found in-
cluding one of the highest products of the plant, namely
the pollen ; for instance, I have seen in an Ophrys a pol-
len-mass with its curious structure of little packets, uni-
ted together and to the caudicle by elastic threads, form-
ed betAveen the edges of an upper petal. The segments
of the calyx of the common pea have been observed par-
tially converted into carpels, including ovules, and with
their tips converted into stigmas. Numerous analogous
facts could be given.50

I do not know how physiologists look at such facts as
the foregoing. According to the doctrine of j>angenesis,
the free and superabundant gemmules of the transposed
organs are developed in the wrong place, from uniting
with wrong cells or aggregates of cells during their nas-
"cent state ; and this would follow from a slight modifica-
tion in the elective affinity of such cells, or possibly of
certain gemmules. Nor ought we to feel much surprise
at the affinities of cells and gemmules varying under
domestication, when we remember the many curious cases

60 Moquin-Tandon, 'Teratologic Ve'g.,' the pea, see 'Gardener's Chron.,' 1866,
1S41, pp. 218, 220, 353. For the case of p. 897.

470 PROVISIONAL HYPOTHESIS Chap. XXVII.

given, in the seventeenth chapter, of cultivated plants
which absolutely refuse to be fertilised by their own pol-
len or by that of the same species, but are abundantly
fertile with pollen of a distinct species ; for this implies
that their sexual elective affinities — and this is the term
used by Gartner — have been modified. As the cells of
adjoining or homologous parts will have nearly the same
nature, they will be liable to acquire by variation each
other's elective affinities ; and we can thus to a certain
extent understand such cases as a crowd of horns on the
heads in certain sheep, of several spurs on the leg, and
of hackles on the head of the fowl, and with the pigeon
the occurrence of wing-feathers on their legs and of mem-
brane between their toes; for the leg is the homologue
of the wing. As all the organs of plants are homologous
and spring from a common axis, it is natural that they
should be eminently liable to transposition. It ought to
be observed that when any compound part, such as an
additional limb or an antenna, springs from a false posi-
tion, it is only necessary that the few first gemmules
should be wrongly attached ; for these whilst developing
would attract others in due succession, as in the regrowth
of an amputated limb. Wben parts which are homolo-
gous and similar in structure, as the vertebrae in snakes
or the stamens in polyandrous flowers, &c, are repeated
many times in the same organism, closely allied gem-
mules must be extremely numerous, as well as the points
to which they ought to become united ; and, in accord-
ance with the foregoing views, we can to a certain extent
understand Isid. Geoffroy St. Hilaire's law, namely, that*
parts, which are already multiple, are extremely liable to
vary in number.

The same general principles apply to the fusion of
homologous parts; and with respect to mere cohesion
there is probably always some degree of fusion, at least
near the surface. When two embryos during their early
development come into close contact, as both include

Chap. XXVII. OF PANGENESIS. 471

corresponding gemmules, which must be in all respects
almost identical in nature, it is not surprising that some
derived from one embryo and some from the other should
unite at the point of contact with a single nascent cell or
aggregate of cells, and thus give rise to a single part or
organ. For instance, two embryos might thus come to
have on their adjoining sides a single symmetrical arm,
Which in one sense will have been formed by the fusion
of the bones, muscles, &c, belonging to the arms of both
embryos. In the case of the fish described by Lereboul-
let, in which a double head was seen gradually to fuse
into a single one, the same process must have taken place,
together with the absorption of all the parts which had
been already formed. These cases are exactly the re-
verse of those in which a part is doubled either spon-
taneously or after an injury ; for in the case of doubling,
the superabundant gemmules of the same part are sepa-
rately developed in union with adjoining points ; whilst
in the case of fusion the gemmules derived from two
homologous parts become mingled and form a single
part ; or it may be that the gemmules from one of two
adjoining embryos alone become developed.

Variability often depends, as I have attempted to show,
on the reproductive organs being injuriously affected by
changed conditions ; and in this case the gemmules de-
rived from the various parts of the body are probably
aggregated in an irregular manner, some superfluous and
others deficient. "Whether a superabundance of gem-
mules, together with fusion during development, would
lead to the increased size of any part cannot be told ;
but we can see that their partial deficiency, without ne-
cessarily leading to the entire abortion of the part, might
cause considerable modifications ; for in the same manner
as a plant, if its own pollen be excluded, is easily hybri-
dised, so in the case of a cell, if the properly succeeding
gemmules were absent, it would probably combine easily

472 PROVISIONAL HYPOTHESIS Chap. XXVII.

with other and allied gemmules. We see this in the
case of imperfect nails growing on the stumps of ampu-
tated fingers," for the gemmules of the nails have mani-
festly been developed at the nearest point.

In variations caused by the direct action of changed
conditions, whether of a definite or indefinite nature, as
with the fleeces of sheep in hot countries, with maize
grown in cold countries, with inherited gout, &c, the
tissues of the body, according to the doctrine of pange-
nesis, are directly affected by the new conditions, and con-
sequently throw off modified gemmules, which are trans-
mitted with their newly acquired peculiarities to the off-
spring. On any ordinary view it is unintelligible how
changed conditions, whether acting on the embryo, the
young or adult animal, can cause inherited modifications.
It is equally or even more unintelligible on any ordinary
view, how the effects of the long-continued use or disuse
of any part, or of changed habits of body or mind, can
be inherited. A more perplexing problem can hardly be
proposed ; but on our view we have only to suppose that
certain cells become at last not only functionally but
structurally modified ; and that these throw off similai-ly
modified gemmules. This may occur at any period of
development, and the modification will be inherited at a
corresponding period; for the modified gemmules will
unite in all ordinary cases with the proper preceding
cells, and they will consequently be developed at the
same period at which the modification first arose.. With
respect to mental habits or instincts, we are so pi-ofoundly
ignorant on the relation between the brain and the power
of thought that we do not know whether an inveterate
habit or trick induces any change in the nervous system ;
but when any habit or other mental attribute, or insanity,
is inherited, we must believe that some actual modifica-
tion is transmitted ; M and this implies, according to our

81 Muller's ' Physiology,' Eng. trans., Sir H. Holland in his ' Medical Notes,'
vol. i. p. 407. • 1889; p. 82.

81 See Some remarks to this effect by

Chap. XXVII. OF PANGENESIS. 473

hypothesis, that gemmules derived from modified nerve-
cells are transmitted to the offspring.

It is generally, perhaps always, necessary that an or-
ganism should be exposed during several generations
to changed conditions or habits, in order that any modi-
fication in the structure of the offspring should ensue.
This may be partly due to the changes not being at first
marked enough to catch the attention, but this explana-
tion is insufficient ; and I can account for the fact only
by the assumption, which we shall see under the head of
reversion is strongly supported, that gemmules derived
from each cell before it had undergone the least modifi-
cation are transmitted in large numbers to successive
generations, but that *the gemmules derived from the
same cells after modification, naturally go on increasing
under the same favouring conditions, until at last they
become sufficiently numerous to overpower and supplant
the old gemmules.

Another difficulty may be here noticed ; we have seen
that there is an important difference in the frequency,
though not in the nature, of the variations in plants pro-
pagated by sexual and asexual, generation. As far as
variability depends on the imperfect action of the repro-
ductive organs under changed conditions, we can at once
see why seedlings should be far more variable than plants
propagated by buds. We know that extremely slight
causes, — for instance, whether a tree has been grafted
or grows on its own stock, the position of the seeds
Avithin the capsule, and of the flowers on the spike, —
sometimes suffice to determine the variation of a plant,
when raised from seed. Now, it is probable, as explained
when discussing alternate generation, that -a bud is
formed of a portion of already differentiated tissue ;
consequently an organism thus formed does not pass
through the earlier phases of development, and cannot
be so freely exposed, at the age when its structure would
be most readily modified, to the various causes inducing

474 PRO VISIONAL HYPOTHESIS Cjap. XXVII.

variability; but it is very doubtful whether this is a
sufficient explanation of the difficulty.

With respect to the tendency to reversion, there is a
similar difference between plants propagated from buds
and seed. Many varieties, whether originally produced
from seed or buds, can be securely propagated by buds,
but generally or invariably revert by seed. So, also,
hybridised plants can be multiplied to any extent by
buds, but are continually liable to reversion by seed, —
that is, to the loss of their hybrid or intermediate cha-
racter. I can offer no satisfactory explanation of this
fact. Here is a still more perplexing case : certain plants
with variegated leaves, phloxes with striped flowers,
barberries with seedless fruit, can all be securely propa-
gated by the buds on cuttings ; but the buds developed
from the roots of these cuttings almost invariably lose
their character and revert to their former condition.

Finally, we can see on the hypothesis of pangenesis
that variability depends on at least two distinct groups
of causes. Firstly, on the deficiency, superabundance,
fusion, and transposition of gemmules, and on the rede-
velopment of those which have long been dormant. In
these cases the gemmules themselves have undergone no
modification ; but the mutations in the above respects
will amply account for much fluctuating variability.
Secondly, in the cases in which the organisation has been
modified by changed conditions, the increased use or dis-
use of parts, or any other cause, the gemmules cast off
from the modified units of the body will be themselves
modified, and, when sufficiently multiplied, will be devel-
oped into new and changed structures.

Turning now to Inheritance: if we suppose a homoge-
neous gelatinous protozoon to vary and assume a reddish
colour, a minute separated atom would naturally, as it
grew to full size, retain the same colour ; and we should

Chap. XXVII. of PANGENESIS. 475

have the simplest form of inheritance." Precisely the
same view may he extended to the infinitely numerous
and diversified units of which the whole "body in one of
the higher animals is composed ; and the separated atoms
are our gemmules. "We have already sufficiently discus-
sed the inheritance of the direct effects of changed con-
ditions, and of increased use or disuse of parts, and, by
implication, the important principle of inheritance at cor-
responding ages. These groups of facts ax*e to a large
extent intelligible on the hypothesis of pangenesis, and
on no other hypothesis as yet advanced.

A few words must be added on the complete abortion
or suppression of organs. When a part becomes dimi-
nished by disuse prolonged during many generations,
the principle of economy of growth, as previously ex-
plained, will tend to reduce it still further; but this will
not account for the complete or almost complete oblitera-
tion of, for instance, a minute papilla of cellular tissue re-
presenting a pistil, or of a microscopically minute nodule
of bone representing a tooth. In certain cases of sup-
pression not yet completed, in which a rudiment occa-
sionally reappears through reversion, diffused gemmules
derived from this part must, according to our view, still
exist ; hence we must suppose that the cells, in union
with which the rudiment was formerly developed, in
these cases fail in their affinity for such gemmules. But
in the cases of complete and final abortion the gemules
themselves no doubt hjive perished ; nor is this in any
way improbable, for, though a vast number of active and
long-dormant gemmules are diffused and nourished in
each living creature, yet there must be some limit to
their number; and it appears natural that gemmules de-
rived from an enfeebled and useless rudiment Avould be

83 This is the view taken by Prof. Hie- tuirten Materie im elterlichen und im

kel, in his ' Generelle Morphologie' (B. kindlichen Organismus, die Theilung

ii. s. 171), who says : " Lediglich die dieser Materie bei der Fortpflanzung, ist

partielle Identitat der specifisch-constl- die Ursache der Erblichkeit."

476 PROVISIONAL HYPOTHESIS Chap. XXVII.

more liable to perish than those derived from other parts
which are still in full functional activity.

With respect to mutilations, it is certain that a part
may be removed or injured during many generations, and
no inherited result follow; and this is an apparent objec-
tion to the hypothesis which will occur to every one.
But, in the first place, a being can hardly be intentionally
mutilated during its early stages of growth whilst in
the womb or egg ; and such mutilations, when naturally
caused, would appear like congenital deficiencies, which
are occasionally inherited. In the second place, accord-
ing to our hypothesis, gemmules multiply by self-division
and are transmitted from generation to generation ; so
that during a long period they would be present and
ready to reproduce a part which was repeatedly ampu-
tated. Nevertheless it appears, from the facts given in
the twelfth chapter, that in some rare cases mutilations
have been inherited, but in most of these the mutilated
surface became diseased. In this case it may be conjec-
tured that the gemmules of the lost part were gradually
all attracted by the partially diseased surface, and thus
perished. Although this would occur in the injured indi-
vidual alone, and therefore in only one parent, yet this
might suffice for the inheritance of a mutilation, on the
same principle that a hornless animal of either sex, when
crossed with a perfect animal of the opposite sex, often
transmits its deficiency.

The last subject that need he|^ be discussed, namely
Reversion, rests on the principle that transmission and
development, though generally acting in conjunction, are
distinct powers ; and the transmission of gemmules and
their subsequent development show us how the existence
of these two distinct powers is possible. We plainly see
this distinction in the many cases in which a grandfather
transmits to his grandson, through his daughter, charac-
ters which she does not, or cannot, possess. Why the de-
velopment of certain characters, not necessarily in any

Chap. XXVII. OF PANGENESIS. 477

way connected with the reproductive organs, should be
confined to one sex alone — that is, why certain cells in
one sex should unite with and cause the development of
certain gemmules — we do not in the least know ; but it
is the common attribute of most organic beings in which
the sexes are separate.

The distinction between transmission and development
is likewise seen in all ordinary cases of Reversion ; but
before discussing this subject it may be advisable to say
a few words on those characters which I have called la-
tent, and which would not be classed under Reversion
in its usual sense. Most, or perhaps all, the secondary
characters, which appertain to one sex, lie dormant in
the other sex ; that is, gemmules capable of development
into the secondary male sexual characters are included
within the female ; and conversely female characters in
the male. Why in the female, when her ovaria become
diseased or fail to act, certain masculine gemmules be-
come developed, we do not clearly know, any more than
why when a young bull is castrated his horns continue
growing until they almost resemble those of a cow ; or
why, when a stag is castrated, the gemmules derived
from the antlers of his progenitors quite fail to be devel-
oped. But in many cases, with variable organic beings,
the mutual affinities of the cells and gemmules become
modified, so that parts are transposed or multiplied ; and
it would apjaear that a slight change in the constitution
of an animal, in connection with the state of the repro-
ductive organs, leads to changed affinities in the tissues
of various parts of the body. Thus, when male animals
first arrive at puberty, and subsequently during each re-
current season, certain cells or parts acquire an affinity
for certain gemmules, which become developed into the
secondary masculine characters ; but if the reproductive
organs be destroyed, or even temporarily disturbed by
changed conditions, these affinities are not excited. Nev-
ertheless, the male, before he arrives at puberty, and dur-

478 PEOVISIONAL HYPOTHESIS Chap. XXVII.

ing the season when the species does not breed, must in-
clude the proper gemmules in a latent state. The curious
case formerly given of a Hen which assumed the mascu-
line characters, not of her own breed but of a remote
progenitor, illustrates the connexion between latent sex-
ual characters and ordinary reversion. With those ani-
mals and plants which habitually produce several forms,
as with certain butterflies described by Mr. Wallace, in
which three female forms and the male exist, or as with
the trimorphic species of Ly thrum and Oxalis, gemmules
capable of reproducing several widely-different forms
must be latent in each individual.

The same principle of the latency of certain characters,
combined with the transposition of organs, may be ap-
plied to those singular cases of butterflies and other in-
sects, in which exactly one half or one quarter of the
body resembles the male, and the other half or three
quarters the female ; and when this occurs the opposite
sides of the body, separated from each other by a dis-
tinct line, sometimes differ in the most conspicuous man-
ner. Again, these same principles apply to the cases
given in the thirteenth chapter, in which the right and
left sides of the body differ to an extraordinary degree,
as in the spiral winding of certain shells, and as in the
genus Verruca among cirripedes ; for in these cases it is
known that either side indifferently may undergo the
same remarkable change of development.

Reversion, in the ordinary sense of the word, comes
into action so incessantly, that it evidently forms an es-
sential part of the general law of inheritance. It occurs
with beings, however propagated, whether by buds or
seminal generation, and sometimes may even be observed
in the same individual as it advances in age. The ten-
dency to reversion is often induced by a change of condi-
tions, and in the plainest manner by the act of crossing.
Crossed forms are generally at first nearly intermediate
in character between their two parents; but in the next

Chap. XXVII. OF PANGENESIS. 479

generation the offspring generally revert to one or both
of their grandparents, and occasionally to more remote
ancestors. How can we account for these facts ? Each
organic unit in a hybrid must throw off, according to
the doctrine of pangenesis, an abundance of hybridised
gemmules, for crossed plants can be readily and largely
propagated by buds ; but by the same hypothesis there
will likewise be present dormant gemmules derived from
both pure parent-forms ; and as these latter retain their
normal condition, they would, it is probable, be enabled
to multiply largely during the lifetime of each hybrid.
Consequently the sexual elements of a hybrid will in-
clude both pure and hybridised gemmules ; and when
two hybrids pair, the combination of pure gemmules de-#
rived from the one hybrid with the pure gemmules of
the same parts derived from the other would necessarily
lead to complete reversion of character; and it is, per-
haps, not too bold a supposition that unmodified and un-
deteriorated gemmules of the same nature would be espe-
cially apt to combine. Pure gemmules in combination
with hybridised gemmules would lead to partial rever-
sion. And lastly, hybridised gemmules derived from
both parent-hybrids would simply reproduce the origi-
nal hybrid form.54 All these cases and degrees of rever-
sion incessantly occur.

It was shown in the fifteenth chapter that certain cha-
racters are antagonistic to each other or do not readily
blend together ; hence, when two animals with antago-
nistic characters are crossed, it might well happen that a
sufficiency of gemmules in the male alone for the repro-
duction of his peculiar charactei-s, and in the female alone
for the reproduction of her peculiar characters, would
not be present ; and in this case dormant gemmules de-
rived from some remote progenitor might easily gain the

64 In these remarks I, in fact, follow crossed. See his excellent memoir in
Naudin, who speaks of the elements or the ' Nouvelles Archives du Museum,'
essences of the two species which are torn. i. p. 151.

480 PEOVISIONAL HYPOTHESIS Chap. XXVII.

ascendency, and cause the reappearance of long-lost cha-
racters. For instance, Avhen black and white pigeons, or
black and white fowls, are crossed, — colours which do not
readily blend, — blue plumage in the one case, evidently
derived from the rock-pigeon, and red plumage in the
other case, derived from the wild jungle-cock, occasionally
reappear. "With uncrossed breeds the same result would
follow, under conditions which favoured the multiplica-
tion and development of certain dormant gemmules, as
when animals become feral and revert to their pristine
character. A certain number of gemmules being requisite
for the development of each character, as is known to be
the case from several spermatozoa or pollen-grains being
necessary for fertilisation, and time favouring their multi-
plication, will together account for the curious cases, in-
sisted on by Mr. Sedgwick, of certain diseases regularly
appearing in alternate generations. This likewise holds
good, more or less strictly, with other weakly inherited
modifications. Hence, as I have heard it remarked, cer-
tain diseases appear actually to gain strength by the in-
termission of a generation. The transmission of dormant
gemmules during many successive generations is hardly
in itself more improbable, as previously remarked, than
that the retention during many ages of rudimentary or-
gans, or even only of a tendency to the production of a
rudiment; but there is no reason to suppose that all
dormant gemmules would be transmitted and propagated
for ever. Excessively minute and numerous as they are
believed to be, an infinite number derived, during a long
course of modification and descent, from each cell of each
progenitor, could not be supported or nourished by the
organism. On the other hand, it does not seem improba-
ble that certain gemmules, under favourable conditions,
should be retained and go on multiplying for a longer
period than others. Finally, on the views here given, we
certainly gain some clear insight into the wonderful fact
that the child may depart from the type of both its pa-

Chap. XXVII. OF PANGENESIS. 481

rents, and resemble its grandparents, or ancestors remov-
ed by many generations.

Conclusion.

The hypothesis of Pangenesis, as applied to the several
great classes of facts just discussed, no doubt is extreme-
ly complex ; but so assuredly are the facts. The assump-
tions, however, on which the hypothesis rests cannot be
considered as complex in any extreme degree — namely,
that all organic units, besides having the power, as is
generally admitted, of growing by self-division, throw
oft' free and minute atoms of their contents, that is gem-
mules. These multiply and aggregate themselves into
buds and the sexual elements ; their development depends
on their union with other nascent cells or units ; and they
are capable of transmission in a dormant state to succes-
sive generations.

In a highly organised and complex animal, the gem-
mules thrown off from each different cell or unit through-
out the body must be inconceivably numerous and minute.
Each unit of each part, as it changes during develop-
ment, and we know that some insects undergo at least
twenty metamorphoses, must throw off its gemmules. All
organic beings, moreover, include many dormant gem-
mules derived from their grandparents and more remote
progenitors, but not from all their progenitors. These
almost infinitely numerous and minute gemmules must be
included in each bud, ovule, spermatozoon, and pollen-
grain. Such an admission will be declared impossible;
but, as previously remarked, number and size are only
relative difficulties, and the eggs or seeds produced by
certain animals or plants are so numerous that they can-
not be grasped by the intellect.

The organic particles with which the wind is tainted
over miles of space by certain offensive animals must be
infinitely minute and numerous; yet they strongly affect

482 PEOVISIONAL HYPOTHESIS Chap. XXVII.

the olfactory nerves. An analogy more appropriate is
afforded by the contagious particles of certain diseases,
which are so minute that they float in the atmosphere
and adhere to smooth paper; yet we know how largely
they increase within the human body, and how power-
fully they act. Independent organisms exist which are
barely visible under the highest powers of our recently-
improved microscopes, and which probably are fully as
large as the cells or units in one of the higher animals ;
yet these organisms no doubt reproduce themselves by
germs of extreme minuteness, relatively to their own
minute size. Hence the difficulty, which at first appears
insurmountable, of believing in the existence of gemmules
so numerous and so small as they must be according to
our hypothesis, has really little weight.

The cells or units of the body are generally admitted
by physiologists to be autonomous, like the buds on a
tree, but in a less degree. I go one step further and as-
sume that they throw off reproductive gemmules. Thus
an animal does not, as a whole, generate its kind through
the sole agency of the reproductive system, but each
separate cell generates its kind. It has often been said
by naturalists that each cell of a plant has the actual or
potential capacity of reproducing the whole plant ; but
it has this power only in virtue of containing gemmules
derived from every part. If our hypothesis be provision-
ally accepted, we must look at all the forms of asexual
reproduction, whether occurring at maturity or as in the
case of alternate generation during youth, as fundamen-
tally the same, and dependent on the mutual aggregation
and multiplication of the gemmules. The regrowth of
an amputated limb or the healing of a wound is the same
process partially carried out. Sexual generation differs
in some important respects, chiefly, as it would appear,
in an insufficient number of gemmules being aggregated
within the separate sexual elements, and probably in the
presence of certain primordial cells. The development

Cbap. XXVII. OF PANGENESIS. 483

of each being, including all the forms of metamorphosis
and metagenesis, as well as the so-called growth of the
higher animals, in which structure changes though not
in a striking manner, depends on the presence of gem-
mules thrown off at each period of life, and on their de-
velopment, at a corresponding period, in union with pre-
ceding cells. Such cells may be said to be fertilised by
the gemmules which come next in the order of develop-
ment. Thus the ordinary act of impregnation and the
development of each being are closely analogous pro-
cesses. The child, strictly speaking, does not grow into the
man, but includes germs which slowly and successively
become developed and form the man. In the child, as
well as in the adult, each part generates the same part
for the next generation. Inheritance must be looked at
as merely a form of growth, like the self-division of a
lowly-organised unicellular plant. Reversion depends on
the transmission from the forefather to his descendants
of dormant gemmules, which occasionally become deve-
loped under certain known or unknown conditions. Each
animal and plant may be compared to a bed of mould
full of seeds, most of which soon germinate, some lie for
a period dormant, whilst others perish. When we hear
it said that a man carries in his constitution the seeds of
an inherited disease, there is much literal truth in the
expression. Finally, the power of propagation possessed
by each separate cell, using the term in its largest sense,
determines the reproduction, the variability, the develop-
ment and renovation of each living organism. No other
attempt, as far as I am aAvare, has been made, imperfect
as this confessedly is, to connect under one point of view
these several grand classes of facts. "We cannot f:\thom
the marvellous complexity of an organic being ; but on
the hypothesis here advanced this complexity is much in-
creased. Each living creature must be looked at as a
microcosm — a little universe, formed of a host of self-
propagating organisms, inconceivably minute and as nu-
merous as the stars in heaven.

484 CONCLUDING REMARKS. Chap. XXVIII.

CHAPTER XXVIII.

CONCLUDING REMARKS.

DOMESTICATION — NATURE AND CAUSES OP VARIABILITY — SELEC-
TION— DIVERGENCE AND DISTINCTNESS OP CHARACTER — EX-
TINCTION OP RACES — CIRCUMSTANCES FAVOURABLE TO SELECTION

• BY MAN — ANTIQUITY OP CERTAIN RACES — THE QUESTION "WHE-
THER EACH PARTICULAR VARIATION HAS BEEN SPECIALLY PRE-
ORDAINED.

As summaries have been added to nearly all the chap-
ters, and as, in the chapter on pangenesis, various sub-
jects, such as the forms of reproduction, inheritance,
reversion, the causes and laws of variability, &c, have
been recently discussed, I will here only make a few gen-
eral remarks on the more important conclusions which
may be deduced from the multifarious details given
throughout this work.

Savages in all parts of the world easily succeed in
taming wild animals ; and those inhabiting any country
or island, when first invaded by man, would probably
have been still more easily tamed. Complete subjugation
generally depends on an animal being social in its habits,
and on receiving man as the chief of the herd or family.
Domestication implies almost complete fertility under
new and changed conditions of life, and this is far from
being invariably the case. An animal would not have
been worth the labour of domestication, at least during
early times, unless of service to man. From these cir-
cumstances the number of domesticated animals has
never been large. With respect to plants, I have shown

Chap. XXVIII. CONCLUDING REMARKS. 485

in the ninth chapter how their varied uses were proba-
bly first discovered, and the early steps in their cultiva-
tion. Man could not have known, when he first domes-
ticated an animal or plant, whether it would flourish and
multiply when transported to other countries, therefore
he could not have been thus influenced in his choice. "We
see that the close adaptation of the reindeer and camel
to extremely cold and hot countries has not prevented
their domestication. Still less could man have foreseen
whether his animals and plants would vary in succeed-
ing generations and thus give birth to new races ; and
the small capacity of variability in the goose and ass has
not prevented their* domestication from the remotest
epoch.

With extremely few exceptions, all animals and plants
which have been long domesticated, have varied greatly.
It matters not under what climate, or for what purpose,
they are kept, whether' as food for man or beast, for
draught or hunting, for clothing or mere pleasure, — un-
der all these circumstances domesticated animals and
plants have varied to a much greater extent than the
forms which in a state of nature are ranked as one spe-
cies. Why certain animals and plants have varied more
under domestication than others w.e do not know, any
more than why some are rendered more sterile than others
under changed conditions of life. But we frequently
judge of the amount of variation by the production of
numerous and diversified races, and we can clearly see
why in many cases this has not occurred, namely, because
slight successive variations have not been steadily accu-
mulated ; and such variations will never be accumulated
when an animal or plant is not closely observed, or much
valued, or kept in large numbers.

The fluctuating, and, as far as we can judge, never-
ending variability of our domesticated productions, —
the plasticity of their whole organization, — is one of the
most important facts which we learn from the numerous

486 CONCLUDING EEMAEKS. Chap. XXVIII.

details given in the earlier chapters of this work. Yet
domesticated animals and plants can hardly have been
exposed to greater changes in their conditions than have
many natural species during the incessant geological,
geographical, and climatal changes of the whole world.
The former will, however, commonly have been exposed
to more sudden changes and to less continuously uniform
conditions. As man has domesticated so many animals
and plants belonging to widely different classes, and as
he certainly did not with prophetic instinct choose those
species which Avould vary most, we may infer that all
natural species, if subjected to analogous conditions,
would, on an average, vary to the same degree. Few
men at the present day will maintain that animals and
plants were created with a tendency to vary, which long
remained dormant, in order that fanciers in' after ages
might rear, for instance, curious breeds of the fowl, pi-
geon, or canary-bird.

From several causes it is difficult to judge of the
amount of modification which our domestic productions
have undergone. In some cases the primitive parent-
stock has become extinct, or cannot be recognised with
certainty owing to its supposed descendants having been
so much modified. In other cases two or more closely
allied forms, after being domesticated, have crossed ; and
then it is difficult to estimate how much of the change
ought to be attributed to variation. But the degree to
which our domestic breeds have been modified by the
crossing of distinct natural forms has probably been ex-
aggerated by some authors. A few individuals of one
form woi.ld seldom permanently affect another form ex-
isting in much greater numbers ; for, without careful se-
lection, the stain of the foreign blood would soon be ob-
literated, and during early and barbarous times, when our
animals Arere first domesticated, such care would seldom
have be< n taken.

There is good reason to believe that several of the

Cuap. xxviii. CONCLUDING REMARKS. 487

breeds of the dog, ox, pig, and of some other animals, are
respectively descended from distinct wild prototypes ;
nevertheless the belief in the multiplc'origin of our domes-
ticated animals has been extended by some few natur-
alists and by many breeders to an unauthorised extent.
Breeders refuse to look at the whole subject under a sin-
gle point of view; I have heard one, who maintained that
our fowls were the descendants of at least half-a-dozen
aboriginal species, protest that he was in no way con-
cerned with the origin of pigeons, ducks, rabbits, horses,
or any other animal. They overlook the improbability
of many species having been domesticated at an early
and barbarous period. They do not consider the improb-
ability of species having existed in a state of nature which,
if like our present domestic breeds, would have been highly
abnormal in comparison with all their congeners. They
maintain that certain species, which formerly existed, have
become extinct or unknown, although the world is now
so much better known. The assumption of so much re-
cent extinction is no difficulty in their eyes ; for they do
not judge of its probability by the facility or difficulty
of the extinction of other closely allied wild forms.
Lastly, they often ignore the whole subject of geographi-
cal distribution as completely as if its laws were the re-
sult of chance.

Although from the reasons just assigned it is often dif-
ficult to judge accurately of the amount of change which
our domesticated productions have undergone, yet this
can be ascertained in the cases in which we know that all
the breeds are descended from a single species, as with
the pigeon, duck, rabbit, and almost certainly with the
fowl ; and by the aid of analogy this is to a certain ex-
tent possible in the case of animals descended from sev-
eral wild stocks. It is impossible to read the details
given in the earlier chapters, and in many published
works, or to visit our various exhibitions, without being
deeply impressed with the extreme variability of our do-

488 CONCLUDING KEMAKKS. Chap. XXVnX

mesticated animals and cultivated plants. I have in many
instances purposely given details on new and strange
peculiarities which have arisen. No part of the organi-
sation escapes the tendency to vary. The variations gen-
erally affect parts of small vital or physiological import-
ance, but so it is with the differences which exist between
closely allied species. In these unimportant characters
there is often a greater difference between the breeds of
the same species than between the natural species of the
same genus, as Isidore Geoffroy has shown to be the case
with size, and as is often the case with the colour, texture,
form, &c, of the hair, feathers, horns, and other dermal
appendages.

It has often been asserted that important parts never
vary under domestication, but this is a complete error.
Look at the skull of the pig in any one of the highly im-
proved breeds, with the occipital condyles and other parts
greatly modified ; or look at that of the niata ox. Or
again, in the several breeds of the rabbit, observe the
elongated skull,, with the differently shaped occipital fo-
ramen, atlas, and other cervical vertebra?. The whole
shape of the brain, together with the skull, has been modi-
fied in Polish fowls ; in other breeds of the fowl the
number of the vertebrae and the forms of the cervical ver-
tebrse have been changed. In certain pigeons the shape
of the lower jaw, the relative length of the tongue, the
size of the nostrils and eyelids, the number and shape of
the ribs, the form and size of the oesophagus, have all va-
ried. In certain quadrupeds the length of the intestines
has been much increased or diminished. With plants we
see wonderful differences in the stones of various fruits.
In the Cucurbitacese several highly important characters
have varied, such as the sessile position of the stigmas on
the ovarium, the position of the carpels within the ova-
rium, and its projection out of the receptacle. But it
would be useless to run through the many facts given in
the earlier chapters.

Chap. XXVIIL CONCLUDING REMARKS. 489

It is notorious how greatly the mental disposition,
tastes, habits, consensual movements, loquacity or silence,
and the tone of voice have varied and been inherited
-with our domesticated animals. The dog offers the most
striking instance of changed mental attributes, and these
differences cannot be accounted for by descent from dis-
tinct wild types. New mental characters have certainly
often been acquired, and natural ones lost, under domes-
tication.

New characters may appear and disappear at any stage
of growth, and be inherited at a corresponding period.
We see this in the difference between the eggs of various
breeds of the fowl and in the down on chickens ; and
still more plainly in the differences between the cater-
pillars and cocoons of various breeds of the silk-moth.
These facts, simple as they appear, throw light on the
characters which distinguish the larval and adult states
of natural species, and on the whole great subject of em-
bryology. New characters are liable to become attached
exclusively to that sex in which they first appeared, or
they may be developed in a much higher degree in the
one than the other sex ; or again, after having become
attached to one sex, they may be partially transferred to
the opposite sex. These facts, and more especially the
circumstance that new characters seem to be particularly
liable, from some unknown cause, to become attached to
the male sex, have an important bearing on the acquire*
ment by animals in a state of nature of secondary sexual
characters.

It has sometimes been said that our domestic produc-
tions do not differ in constitutional peculiarities, but this
cannot be maintained. In our improved cattle, pigs, &c,
the period of maturity, including that of the second den-
tition, has been much hastened. The period of gestation
varies much, but has been modified in a fixed manner in
only one or two cases. In our poultry and pigeons the
acquirement of down and of the first plumage by the

490 CONCLUDING REMARKS. Chap. XXVIII.

young, and of the secondary sexual characters by the
males, differ. The number of moults through which
the larvae of silk-moths pass, varies. The tendency to
fatten, to yield much milk, to produce many young or
eggs at a birth or during life, differs in different breeds.
We find different degrees of adaptation to climate, and
different tendencies to certain diseases, to the attacks of
parasites, and to the action of certain vegetable poisons.
With plants, adaptation to certain soils, as "with some
kinds of plums, the power of resisting frost, the period
of flowering and fruiting, the duration of life, the period
of shedding the leaves and of retaining them throughout
the winter, the proportion and nature of certain chemical
compounds in the tissues or seeds, all vary.

There is, however, one impoi'tant constitutional differ-
ence between domestic races and species ; I refer to the
sterility which almost invariably follows, in a greater or
less degree, when species are crossed, and to the perfect
fertility of the most distinct domestic races, with the ex-
ception of a very few plants, when similarly crossed. It
certainly appears a remarkable fact that many closely
allied species which in appearance differ extremely little
should yield when united only a few, more or less sterile
offspring, or none at all ; whilst domestic races which
differ conspicuously from each other, are when united
remarkably fertile, and yield perfectly fertile offspring.
But this fact is not in reality so inexplicable as it at first
appears. In the first place, it was clearly shown in the
nineteenth chapter that the sterility of crossed species
does not closely depend on differences in their external
structure or general constitution, but results exclusively
from differences in the reproductive system, analogous
with those which cause the lessened fertility of the illegi-
timate unions and illegitimate offspring of dimorphic and
trimorphic plants. In the second place, the Pallasian
doctrine, that species after having been long domesticat-
ed lose their natural tendency to sterility when crossed,

chap, xxviii. CONCLUDING REMARKS. 491

has been shown to be highly probable ; we can scarcely
avoid this conclusion when we reflect on the parentage
and present fertility of the several breeds of the dog, of
Indian and European cattle, sheep, and pigs. Hence it
would be unreasonable to expect that races formed un-
der domestication should acquire sterility when crossed,
whilst at the same time we admit that domestication
eliminates the normal sterility of crossed species. Why
with closely allied species their reproductive systems
should almost invariably have been modified in so peculiar
a manner as to be mutually incapable of acting on each
other — though in unequal degrees in the two sexes, as
shown by the difference in fertility between reciprocal
crosses in the same species — we 'do not know, but may
with much probability infer the cause to be as follows.
Most natural species have been habituated to nearly
uniform conditions of life for an incomparably longer
period of time than have domestic races ; and we posi-
tively know that changed conditions exert an especial
and powerful * influence on the reproductive system.
Hence this difference in habituation may well account
for the different action of the reproductive organs when
domestic races and when species are crossed. It is a
nearly analogous fact, that most domestic races may be
suddenly transported from one climate to another, or be
placed under widely different conditions, and yet retain
their fertility unimpaired ; whilst a multitude of species
subjected to lesser changes are rendered incapable of
breeding.

With the exception of fertility, domestic varieties re-
semble species when crossed in transmitting their charac-
ters in the same unequal manner to their offspring, in
being subject to the prepotency of one form over the
other, and in their liability to reversion. By repeated
crosses a variety or a species may be made completely to
absorb another. Varieties, as we shall see when we treat
of their antiquity, sometimes inherit their new characters

492 CONCLUDING REMARKS. Chap. XXVIII.

almost, or even quite, as firmly as species. With both,
the conditions leading to variability and the laws govern-
ing its nature appear to be the same. Domestic varieties
can be classed in groups under groups, like species under
genera, and these under families and orders; and the
classification may be either artificial, — that is, founded on
any arbitrary character, — or natural. With varieties a
natural classification is certainly founded, and with spe-
cies is apparently founded, on community of descent, to-
gether with the amount of modification which the forms
have undergone. The characters by which domestic va-
rieties differ from each other are more variable than those
distinguishing species, though hardly more so than with
certain protean species ; but this greater degree of varia-
bility is not surprising, as varieties have generally been
exposed within recent times to fluctuating conditions of
life, are much more liable to have been crossed, and are
still in many cases undergoing, or have recently under-
gone, modification by man's methodical or unconscious
selection.

Domestic varieties as a general rule certainly differ
from each other in less important parts of their organisa-
tion than do species ; and when important differences
occur, they are seldom firmly fixed ; but this fact is intel-
ligible if we consider man's method of selection. In the
living animal or plant he cannot observe internal modifi-
cations in the more important organs ; nor does he regard
them as long as they are compatible with health and life.
What does the breeder care about any slight change in
the molar teeth of his pigs, or for an additional molar
tooth in the dog ; or for any change in the intestinal
canal or other internal organ ? The breeder cares for the
flesh of his cattle being well marbled with fat, and for an
accumulation of fat within the abdomen of his sheep, and
this he has effected. What would the floriculturist care
for any change in the structure of the ovarium or of the
ovules? As important internal organs are certainly lia-

Chap. XXVIII. CONCLUDING REMARKS. 493

ble to numerous Blight variations, and as these would
probably be inherited, for many strange monstrosities are
transmitted, man could undoubtedly effect a certain
amount of change in these organs. When he has pro-
duced any modification in an important part, it has gen-
erally been unintentionally in correlation with some other
conspicuous part, as when he has given ridges and pro-
tuberances to the skulls of fowls, by attending to the form
of the comb, and in the case of the Polish fowl to the
plume of feathers on the head. By attending to the ex-
ternal form of the pouter-pigeon, he has enormously in-
creased the size of the oesophagus, and has added to the
number of the ribs, and given them greater breadth.
With the carrier-pigeon, by increasing, through steady
selection, the wattles on the upper mandible, he has great-
ly modified the form of the lower mandible ; and so in
many other cases. Natural species, on the other Hand,
•have been modified exclusively for their own good, to fit
them for infinitely diversified conditions of life, to avoid
enemies of all kinds, and to struggle against a host of
competitors. Hence, under such complex conditions, it
would often happen that modifications of the most varied
kinds, in important as well as in unimportant parts,
would be advantageous or even necessary ; and they
would slowly but surely be acquired through the survival
of the fittest. Various indirect modifications would like-
wise arise through the law of correlated variation.

Domestic breeds often have an abnormal or semi-mon-
strous character, as the Italian greyhound, bulldog, Blen-
heim spaniel, and bloodhound amongst dogs, — some breeds
of cattle and pigs, several breeds of the fowl, and the
chief breeds of the pigeon. The differences between such
abnormal breeds occur in parts which in closely-allied
natural species differ but slightly or not at all. This may
be accounted for by man's often selecting, especially at
first, conspicuous and semi-monstrous deviations of struc-
ture. We should, however, be cautious in deciding what

494 CONCLUDING REMARKS. Chap. XXVIII.

deviations ought to be called monstrous : there can hard-
ly be a doubt that, if the brush of horse-like hair on the
breast of the turkey-cock had first appeared on the do-
mesticated bird, it would have been considered a mon-
strosity; the great plume of feathers on the head of the
Polish cock has been thus designated, though plumes are
common with many kinds of birds ; we might call the
wattle or corrugated skin round the base of the beak of
the English carrier-pigeon a monstrosity, but we do not
thus speak of the globular fleshy excrescence at the base
of the beak of the male Carpophaga oceanica.

Some authors have drawn a wide distinction between
artificial and natural breeds; although in extreme cases
the distinction is plain, in many other cases an arbitrary
line has to be drawn. The difference depends chiefly on
the kind of selection which has been applied. Artificial
breeds are those which have been intentionally improved
by man ; they frequently have an unnatural appearance,
and are especially liable to loss of excellence through re-
version and continued variability. The so-called natural
breeds, on the other hand, are those which are now found
in semi-civilised countries, and which formerly inhabited
separate districts in nearly all the European kingdoms.
They have been rarely acted on by man's intentional selec-
tion ; more frequently, it is probable, by unconscious se-
lection, and partly by natural selection, for animals kept
in semi-civilised countries have to provide largely for
their own wants. Such natural breeds will also, it may
be presumed, have been directly acted on to some extent
by the differences, though slight, in the surrounding physi-
cal conditions.

It is a much more important distinction that some breeds
have been from their first origin modified in so slow and
insensible a manner, that if we could see their early pro-
genitors we should hardly be able to say when or how
the breed first arose ; whilst other breeds have originated
from a strongly-marked or semi-monstrous deviation of

Chip. XXVIII. CONCLUDING REMARKS. 405

structure, which, however, may subsequently have been
augmented by selection. From what we know of the his-
tory of the racehorse, greyhound, gamecock, <fcc, and from
their general appearance, we may feel nearly confident
that they were formed by a slow process of improvement :
and with the carrier-pigeon, as well as with some other
pigeons, we know that this has been the case. On the
other hand, it is certain that the ancon and mauchamp
breeds of sheep, and almost certain that the niata cattle,
turnspit and pug-dogs, jumper and frizzled fowls, short-
faced tumbler pigeons, hook-billed ducks, &c, and with
plants a multitude of varieties, suddenly appeared in near-
ly the same state as we now see them. The frequen-
cy of these cases is likely to lead to the false belief that
natural species have often originated in the same abrupt
manner. But we have no evidence of the appearance,
or at least of the continued procreation, under nature, of
abrupt modifications of structure ; and various general
reasons could be assigned against such a belief: for in-
stance, without separation a single monstrous variation
would almost certainly be soon obliterated by crossing.

On the other hand, we have abundant evidence of the
constant occurrence under nature of slight individual dif-
ferences of the most diversified kinds ; and thus we are
led to conclude that species have generally originated by
the natural selection, not of abrupt modifications, but of
extremely slight differences. This process may be strictly
compared with the slow and gradual improvement of the
racehorse, greyhound, and gamecock. As every detail of
structure in each species is closely adapted to its general
habits of life, it will rarely happen that one part alone will
be modified; but the co-adapted modifications, as formerly
shown, need not be absolutely simultaneous. Many vari-
ations, however, are from the first connected by the law
of correlation. Hence it follows that even closely-allied
species rarely or never differ from each other by some one
character alone ; and this same remark applies to a certain

496 CONCLUDING REMARKS. Chap. XXVIII.

extent to domestic races; for these, if they -differ much,
generally differ in many respects.

Some naturalists boldly insist1 that species are abso-
lutely distinct productions, never passing by intermediate
links into each other ; whilst they maintain that domestic
varieties can always be connected either with each other
or with their parent-forms. But if we could always find
the links between the several breeds of the dog, horse,
cattle, sheep, pigs, &c, the incessant doubts whether they
are descended from one or several species would not have
arisen. The greyhound genus, if such a term may be
used, cannot be closely connected with any other breed,
unless, perhaps, we go back to the ancient Egyptian mo-
numents. Our English bulldog also forms a very distinct
breed. In all these cases crossed breeds must of course
be excluded, for the most distinct natural species can
thus be connected. By what links can the Cochin fowl
be closely united with others ? By searching for breeds
still preserved in distant lands, and by going back to his-
torical records, tumbler-pigeons, carriers, and barbs can
be closely connected with the parent rock-pigeon ; but
we cannot thus connect the turbit or the pouter. The
degree of distinctness between the various domestic
breeds depends on the amount of modification which they
have undergone, and especially on the neglect and final
extinction of the linking, intermediate, and less valued
forms.

It has often been argued that no light is thrown, from
the admitted changes of domestic races, on the changes
which natural species are believed to undergo, as the
former are said to be mere temporary productions, always
reverting, as soon as they become feral, to their pristine
form. This argument has been well combated by Mr.
Wallace ; 2 and full details were given in the thirteenth

1 Godron, 'Del'Espece,' 1859, torn. ii. s Journal Proc. Binn. Soc, 1S58, vol.

p. 44, &c. Ui. p. 60.

Chap. XXVIII. CONCLUDING REMARKS. 497

chapter, showing that the tendency to reversion in feral
animals and plants has been greatly exaggerated, though
no doubt to a certain extent it exists. It would be op-
posed to all the principles inculcated in this work, if
domestic animals, when exposed to new conditions and
compelled to struggle for their own wants against a host
of foreign competitors, were not in the course of time in
some manner modified. It should also be remembered
that many characters lie latent in all organic beings
ready to be evolved under fitting conditions; and in
breeds modified within recent times the tendency to re-
version is particularly strong. But the antiquity of va-
rious breeds clearly proves that they remain nearly con-
stant as long as their conditions of life remain the same.
It has been boldly maintained by some authors that
the amount of variation to which our domestic produc-
tions are liable is strictly limited ; but this is an assertion
resting on little evidence. Whether or not the amount
in any particular direction is fixed, the tendency to gen-
eral variability seems unlimited. Cattle, sheep, and pigs
have been domesticated and have varied from the remot-
est period, as shown by the researches of Riitimeyer and
others, yet these animals have, within quite recent times,
been improved in an unparalleled degree ; and this im-
plies continued variability of structure. Wheat, as we
know from the remains found in the Swiss lake-habita-
tions, is one of the most anciently cultivated plants, yet
at the present day new and better varieties occasionally
arise. It may be that an ox will never be produced of
larger size or finer proportions than our present animals,
or a race-horse fleeter than Eclipse, or a gooseberry
larger than the London variety ; but he would be a bold
man who would assert that the extreme limit in these
respects has been finally attained. With flowers and
fruit it has repeatedly been asserted that perfection has
been reached, but the standard has soon been excelled.
A breed of pigeons may never be produced with a beak

498 CONCLUDING EEMAEKS. Chap. XXVIII.

shorter than that of the present short-faced tumbler, or
with one longer than that of the English carrier, for
these birds have weak constitutions and are bad bi'eeders ;
but the shortness and length of the beak are the points
which have been steadily improved during at least the
last 150 years; and some of the best judges deny that
the goal has yet been reached. We may, also, reasonably
suspect, from what we see in natural species of the varia-
bility of extremely modified parts, that any structure,
after remaining constant during a long series of genera-
tions, would, under new and changed conditions of life,
recommence its course of variability, and might again be
acted on by selection. Nevertheless, as Mr. Wallace 3
has reoently remarked with much force and truth, there
must be both with natural and domestic productions a
limit to change- in certain directions ; for instance, there
must be a limit to the fleetness of any terrestrial animal,
as this will be determined by the friction to be overcome,
the weight to be carried, and the power of contraction in
the muscular fibres. The English race-horse may have
reached this limit ; but it already surpasses in fleetness
its own wild progenitor, and all other equine species.

It is not surprising, seeing the great difference be-
tween many domestic breeds, that some few naturalists
have concluded that all are descended from distinct
aboriginal stocks, more especially as the principle of
selection has been ignored, and the high antiquity of
man, as a breeder of animals, has only recently become
known. Most naturalists, however, freely admit that
various extremely dissimilar breeds are descended from
a single stock, although they do not know much about
the art of breeding, cannot show the connecting links,
nor say where and when the breeds arose. Yet these
same naturalists will declare, with an air of philosophi-
cal caution, that they can never admit that one natural

« ' The Quarterly Journal of Science,1 Oct. 1867, p. 486.

Chap. XXVIII. CONCLUDING REMARKS. 499

species has given birth to another until they behold all
the transitional steps. But fanciers have used exactly
the same language with respect to domestic breeds; thus
an author of an excellent treatise says he will never
allow that carrier and fantail pigeons are the descendants
of the wild rock-pigeon, until the transitions have " ac-
" tually been observed, and can be repeated whenever
" man chooses to set about the task." No doubt it is
difficult to realize that slight changes added \ip during
long centuries can produce such results ; but he who
wishes to understand the origin of domestic breeds or
natural species must overcome this difficulty.

The causes inducing and the laws governing variabil-
ity have been so lately discussed, that I need here only
enumerate the leading points. As domesticated organ-
isms are much more liable to slight deviations of struc-
ture and to monstrosities, than species living under their
natural conditions, and as widely-ranging 6pecies vary
more than those which inhabit restricted areas, we may
infer that variability mainly depends on changed con-
ditions of life. We must not overlook the effects of the
unequal combination of the characters derived from both
parents, nor reversion to former progenitors. Changed
conditions have an especial tendency to render the re-
productive organs more or less impotent, as shown in
the chapter devoted to this subject ; and these organs
consequently often fail to transmit faithfully the parental
characters. Changed conditions also act directly and
definitely on the organisation, so that all or nearly all
the individuals of the same species thus exposed become
modified in the same manner ; but why this or that part
is especially affected we can seldom or never say. In
most cases, however, of the direct action of changed
conditions, independently of the indirect variability
caused by the reproductive organs being affected, in-
definite modifications are the result; in nearly the same
manner as exposure to cold or the absorption of the same

500 CONCLUDING REMARKS. Chap. XXVIII.

poison affects different individuals in various ways. We
have reason to suspect that an habitual excess of highly
nutritious food, or an excess relatively to the wear and*
tear of the organisation from exercise, is a powerful
exciting cause of variability. When we see the sym-
metrical and complex outgrowths, caused by a minute
atom of the poison of a gall-insect, we may believe that
slight changes in the chemical nature of the sap or blood
would lead to extraordinary modifications of structure.

The increased use of a muscle with its various attached
parts, and the increased activity of a gland or other
organ, lead to their increased development. Disuse
has a contrary effect. With domesticated productions or-
gans sometimes become rudimentary through abortion ;
but we have no reason to suppose that this has ever fol-
lowed from mere disuse. With natural species, on the
contrary, many organs appear to have been rendered
rudimentary through disuse, aided by the principle of
the economy of growth, and by the hypothetical princi-
ple discussed in the last chapter, namely, the final de-
struction of the germs or gemmules of such useless parts.
This difference may be partly accounted for by disuse
having acted on domestic forms for an insufficient length
of time, and partly from their exemption from any severe
struggle for existence, entailing rigid economy in the
development of each part, to which all species under
nature are subjected. Nevertheless the law of compen-
sation or balancement apparently affects, to a certain
extent, our domesticated productions.

We must not exaggerate the importance of the definite
action of changed conditions in modifying all the indi-
viduals of the same species in the same manner, or of use
and disuse. . As every part of the organisation is highly
variable, and as variations are so easily selected, both
consciously and unconsciously, it is very difficult to dis-
tinguish between the effects of the selection of indefinite
variations, and the direct action of the conditions of life.

Chap. XXVIII. CONCLUDING REMARKS. 501

For instance, it is possible that the feet of our water-
dogs, and of the American dogs which have to travel
much over the snow, may have become partially webbed
from the stimulus of widely extending their toes ; but it
is far more probable that the webbing, like the mem-
brane between the toes of certain pigeons, spontaneously
appeared and was afterwards increased by the best swim-
mers and the best snow-travellers being preserved during
many generations. A fancier who wished to deci'ease the
size of his bantams or tumbler-pigeons would never think
of starving them, but would select the smallest indi-
viduals which spontaneously appeared. Quadrupeds are
sometimes born destitute of hair, and hairless breeds
have been formed, but there is no reason to believe that
this is caused by a hot climate. Within the tropics heat
often causes sheep to lose their fleeces, and on the other
hand wet and cold act as a direct stimulus to the growth
of hair ; it is, however, possible that these changes may
merely be an exaggeration of the regular yearly change
of coat ; and who will pretend to decide how far this
yearly change, or the thick fur of arctic animals, or as I
may add their white colour, is due to the direct action
of a severe climate, and how far to the preservation of
the best protected individuals during a long succession
of generations ?

Of all the laws governing variability, that of correla-
tion is the most important. In many cases of slight de-
viations of structure as well as of grave monstrosities,
we cannot even conjecture what is the nature of the bond
of connexion. But between homologous parts — between
the fore and hind limbs — between the hair, hoofs, horns,
and teeth — we can see that parts which are closely simi-
lar during their early development, and which are ex-
posed to similar conditions, would be liable to be modi-
fied in the same manner. Homologous parts, from having
the same nature, are apt to blend together, and, when
many exist, to vary in number.

502 CONCLUDING REMARKS. Chap. XXVIIL

Although every variation is either directly or indirect-
ly caused by some change in the surrounding conditions,
we must never forget that the nature of the organisation
which is acted on essentially governs the result. Distinct
organisms, when placed under similar conditions, vary in
different manners, whilst closely-allied organisms under
dissimilar conditions often vary in nearly the same man-
ner. We see this in the same modification frequently
reappearing at long intervals of time in the same variety,
and likewise in the several striking cases given of analo-
gous or parallel varieties. Although some of these latter
cases are simply due to reversion, others cannot thus be
accounted for.

From the indirect action of changed conditions on the
organisation, through the impaired state of the reproduc-
tive organs — from the direct action of such conditions
(and this will cause the individuals of the same species
either to vary in the same manner, or differently in ac-
cordance with slight differences in their constitution) —
from the' effects of the increased or decreased use of
parts, — and from correlation, — the variability of our do-
mesticated productions is complicated in an extreme de-
gree. The whole organisation becomes slightly plastic.
Although each modification must have its proper excit-
ing cause, and though each is subjected to law, yet we
can so rarely trace the precise relation between cause
and effect, that we are tempted to speak of variations as
if they spontaneously arose. We may even call them ac-
cidental, but this must be only in the sense in which we
say that a fragment of rock dropped from a height owes
its shape to accident.

It may be worth while briefly to consider the results
of the exposure to unnatural conditions of a large num-
ber of animals of the same species, allowed to cross free-
ly, with no selection of any kind ; and afterwards to con-
sider the results when selection is brought into play.

Ohap. xxviii. CONCLUDING REMARKS. 503

Let us suppose that 500 wild vock-pigeons were confined
in their native land in an aviary, and fed in the same
manner as pigeons usually are ; and that they were not
allowed to increase in number. As pigeons propagate
so rapidly, I suppose that a thousand or fifteen hundred
birds would have to be annually killed by mere chance.
After several generations had been thus reared, we may
feel sure that some of the young birds would vary, and
the variations would tend to be inherited ; for at the
present day slight deviations of structure often occur,
but, as most breeds are already well established, these
modifications are rejected as blemishes. It would be
tedious even to enumerate the multitude of points which
still go on varying or have recently varied. Many vari-
ations would occur in correlation, as the length of the
wing and tail-feathers — the number of the primary wing-
feathers, as well as the number and breadth of the ribs,
in correlation with the size and form of the body — the
number of the scutellje, with the size of the feet — the
length of the tongue, with the length of the beak — the
size of the nostrils and eyelids and the form of lower
jaw in correlation with the development of wattle — the
nakedness of the young with the future colour of the
plumage — the size of the feet and beak, and other such
points. Lastly, as our birds are supposed to be confined
in an aviary, they would use their wings and legs but
little, and certain parts of the skeleton, such as the
sternum and scapulae and the feet, would in consequence
become slightly reduced in size.

As in our assumed case many birds have to be indis-
criminately killed every year, the chances are against any
new variety surviving long enough to breed. And as the
variations which arise are of an extremely diversified na-
ture, the chances are very great against two birds pairing
which have varied in the same manner ; nevertheless, a va-
rying bird even when not thus paired would occasionally
transmit its character to its young ; and these would not

504 CONCLUDING REMARKS. Chap. XXVIII.

only be exposed to the same conditions which first caused
the variation in question to appear, but would in addition
inherit from their one modified parent a tendency again
.to vary in the same manner. So that, if the conditions
decidedly tended to induce some particular variation, all
the birds might in the course of time become similarly
modified. But a far commoner result would be, that one
bird would vary in one way and another bird in another
Avay ; one would be born with a little longer beak, and
another with a shorter beak ; one would gain some black
feathers, another some white or red feathers. And as
these birds would be continually intercrossing, the final
result would be a body of individuals differing from each
other slightly in many ways, yet far more than did the
original rock-pigeons. But there would not be the least
tendency to the formation of distinct breeds.

If two separate lots of pigeons wrere to be treated in
the manner just described, one in England and the other
in a tropical country, the two lots being supplied with
different food, would they, after many generations had
passed, differ ? When we reflect on the cases given in the
twenty-third chapter, and on such facts as the difference
in former times between the breeds of cattle, sheep, &c,
in almost every district of Europe, we are strongly in-
clined to admit that the two lots would be differently mo-
dified through the influence of climate and food. But the
evidence on the definite action of changed conditions is
in most cases insufficient ; and, with respect to pigeons, I
have had th» opportunity of examining a large collection
of domesticated birds, sent to me by Sir W. Elliot from
India, and they varied in a remarkably similar manner
with our European birds.

If two distinct breeds were to be confined together in
equal numbers, there is reason to suspect that they would
to a certain extent prefer pairing with their own kind ;
but they would likewise intercross. From the greater vi-
gour and fertility of the crossed offspring, the whole body

c.iap. xxviii. CONCLUDING REMARKS. 505

would by this means become interblcndcd sooner than
would otherwise have occurred. From certain breeds be-
ing prepotent over others, it does not follow that the in-
terblended progeny would be strictly intermediate in cha-
racter. I have, also, proved that the act of crossing in
itself gives a strong tendency to reversion, so that the
crossed offspring would tend to revert to the state of the
aboriginal rock-pigeon. In the course of time they would
probably be not much more heterogeneous in character
than in our first case, when birds of the same breed were
confined together.

I have just said that the crossed offspring would gain
in vigour and fertility. From the facts given in the
seventeenth chapter there can be no doubt of this ; and
there can be little doubt, though the evidence on this
head is not so easily acquired, that long-continued close
interbreeding leads to evil results. With hermaphrodites
of all kinds, if the sexual elements of the same individual
habitually acted on each other, the closest possible inter-
breeding would be perpetual. Therefore Ave should bear
in mind that with all hermaphrodite animals, as far as I
can learn, their structure permits and frequently neces-
sitates a cross with a distinct individual. With herma-
phrodite plants we incessantly meet with elaborate and
perfect contrivances for this same end. It is no exaggera-
tion to assert that, if the use of the talons and tusks of a
carnivorous animal, or the use of the viscid threads of a
spider's web, or of the plumes and hooks on a seed may
be safely inferred from their structure, Ave may with equal
safety infer that many floAvers are constructed for the ex-
press purpose of ensuring a cross with a distinct plant.
From these Ararious considerations, the conclusion arriAred
at in the chapter just referred to — namely, that great
good of some kind is derived from the sexual concourse of
distinct individuals — must be admitted.

To return to our illustration : Ave have hitherto assum-
ed that the birds Avere kept down to the same number by

506 CONCLUDING REMAKES. Chap. XXVIII.

indiscriminate slaughter; but if the least choice be per-
mitted in their preservation and slaughter, the whole re-
sult will be changed. Should the owner observe any-
slight variation in one of his birds, and wish to obtain a
breed thus characterised, he would succeed in a surpris-
ingly short time by carefully selecting and pairing the
young. As any part which has once varied generally
goes on varying in the same direction, it is easy, by con-
tinually preserving the most strongly marked individuals,
to increase the amount of difference up to a high, pre-
determined standard of excellence. This is methodical
selection.

If the owner of the aviary, without any thought of
making a new breed, simply admired, for instance, short-
beaked more than long-beaked birds, he would, when he
had to reduce the number, generally kill the latter ; and
there can be no doubt that he would thus in the course
of time sensibly modify his stock. It is improbable, if
two men were to keep pigeons and act in this manner,
that they would prefer exactly the same characters ; they
would, as we know, often prefer directly opposite charac
ters, and the two lots would ultimately come to differ.
This has actually occurred with strains or families of cat-
tle, sheep, and pigeons, which, have been long kept and
carefully attended to hy different breeders without any
wish on their part to form new and distinct sub-breeds.
This unconscious kind of selection will more especially
come into action with animals which are highly service-
able to man ; for every one tries to get the best dog, horse,
cow, or sheep, and these animals will transmit more or
less surely their good qualities to their offspring. Hardly
anyone is so careless as to breed from his worst animals.
Even savages, when compelled from extreme want to
kill some of their animals, would destroy the Avorst and
preserve the best. With animals kept for use and not
for mere amusement, different fashions prevail in different
districts, leading to the preservation, and consequently to

Chip, xxviii. CONCLUDING- REMARKS. » 507

the transmission, of all sorts of trifling peculiarities of
character. The same process will have been pursued
with our fruit-trees and vegetables, for the best will al-
ways have been the most largely cultivated, and will
occasionally have yielded seedlings better than their pa-
rents.

The different strains, just alluded to, which have been
raised by different breeders without any wish for such a
result, and the unintentional modification of foreign breeds
in their new homes, both afford excellent evidence of the
power of unconscious selection. This form of selection
has probably led to far more important results than meth-
odical selection, and is likewise more important under a
theoretical point of view from closely resembling natural
selection. For during this process the best or most valued
individuals are not separated and prevented crossing with
others of the same breed, but are simply preferred and
preserved ; but this inevitably leads during a long suc-
cession of generations to their increase in number and to
their gradual improvement; so that finally they prevail
to the exclusion of the old parent-form.

With our domesticated animals natural selection checks
the production of races with any injurious deviation of
structure. In the case of animals kept by savages and
semi-civilised people, which have to provide largely for
their own wants under different circumstances, natural se-
lection will probably play a more important part. Hence
such animals often closely resemble natural species.

As there is no limit to man's desire to possess animals
and plants more and more useful in any respect, and as
the fancier always wishes, from fashion running into ex-
tremes, to produce each character more and more strongly
pronounced, there is a constant tendency in every breed,
through the prolonged action of methodical and uncon-
scious selection, to become more and more different from
its parent-stock ; and when several breeds have been
produced and are valued for different qualities, to differ

5 OS CONCLUDING REMARKS. Chap. XXVIII.

more and more from each other. This leads to Diver-
gence of Character. As improved sub-varieties and
races are slowly formed, the older and less improved
breeds are neglected and decrease in number. When
few individuals of any breed exist within the same local-
ity, close interbreeding, by lessening their vigour and
fertility, aids in their final extinction. Tims the inter-
mediate links are lost, and breeds which have already
diverged gain Distinctness of Character.

In the chapters on the Pigeon, it was proved by histo-
rical details and by the existence of connecting sub-
varieties in distant lands that several breeds have
steadily diverged in character, and that many old and
intermediate sub-breeds have become extinct. Other
cases could be adduced of the extinction of domestic
breeds, as of the Irish wolf-dog, the old English hound,
and of two breeds in France, one of which was formerly
highly valued.4 Mr. Pickering remarks5 that " the sheep
" figured on the most ancient Egyptian monuments is
" unknown at the present day ; and at least one variety
" of the bullock, formerly known in Egypt, has in like
" manner become extinct." So it has been with some
animals, and with several plants cultivated by the an-
cient inhabitants of Europe during the neolithic period.
In Peru, Von Tschudi6 found in certain tombs, apparently
prior to the dynasty of the Incas, two kinds of maize not
now known in the country.' With our flowers and culi-
nary vegetables, the pi'oduction of new varieties and their
extinction has incessantly recurred. At the present time
improved breeds sometimes displace at an extraordina-
rily rapid rate older breeds ; as has recently occurred
throughout England with pigs. The Long-horn cattle
in their native home were " suddenly swept away as if

4 M. Rufz de Lavison, in 'Bull. Soc. 6 ' Travels in Peru,' Eng. translat.,

Imp. d'Acclimat.,' Dec. 1862, p. 1009. ITT.

6 ' Races of Man,' 1850, p. 315.

Chap. XXVIII. CONCLUDING REMARKS. 500

" by some murderous pestilence," by the introduction of
Short-horns.7

What grand results have followed from the long-con
tinned action of methodical and unconscious selection,
checked and regulated to a certain extent by natural
selection, is seen on every side of us. Compare the many
animals and plants Avhich are displayed at our exhibitions
with their parent-forms when these are known, or consult
old historical records with respect to their former state.
Almost all our domesticated animals have given rise to
numerous and distinct races, excepting those which can-
not be easily subjected to selection — such as cats, the
cochineal insect, and the hive-bee, — and excepting those
animals which are not much valued. In accordance with
what we know of the process of selection, the formation
of our many races has been slow and gradual. The man
who first observed and preserved a pigeon with its oeso-
phagus a little enlarged, its beak a little longer, or its
tail a little more expanded than usual, never dreamed
that he had made the first step in the creation of the
pouter, carrier, and fantail-pigeon. Man can create not
only anomalous breeds, but others with their Avhole
structure admirably co-ordinated for certain purposes,
such as the race-horse and dray-horse, or the greyhound.
It is by no means necessary that each small change of
structure throughout the body, leading towards excel-
lence, should simultaneously arise and be selected. Al-
though man seldom attends to differences in organs which
are important under a physiological point of view,
yet he has so profoundly modified some breeds, that
assuredly, if found wild, they would be ranked under
distinct genera.

The best proof of what selection has effected is perhaps
afforded by the fact that whatever part or quality in any
animal, and more especially in any plantj is most valued

7 Youatt on Cattle, 1S34, p. 200 : on Pigs, see ' Gard. Chronicle,' 1S5J, p. 410.

510 CONCLUDING REMARKS. Chap, xxvill.

by man, that part or quality differs most in the several
races. This result is well seen by comparing the amount
of difference between the fruits produced by the varieties
of the same fruit-tree, between the flowers of the varie-
ties in our flower-garden, between the seeds, roots, or
leaves of our culinary and agricultural plants, in compa-
rison with the other and not valued parts of the same
plants. Striking evidence of a different kind is afforded
by the fact ascertained by Oswald Heer,8 namely, that
the seeds of a large number of plants, — wheat, barley,
oats, peas, beans, lentils, j>oppies, — cultivated for their
seed by the ancient Lake-inhabitants of Switzerland,
were all smaller than the seeds of our existing varieties.
Rtltimeyer has shown that the sheep and cattle which
were kept by the earlier Lake-inhabitants were likewise
smaller than our present breeds. In the middens of
Denmark, the earliest dog of which the remains have
been found was the weakest ; this was succeeded during
the Bronze age by a stronger kind, and this again during
the Iron age by one still stronger. The sheep of Den-
mark during the Bronze period had extraordinarily slen-
der limbs, and the horse was smaller than our present
animal.9 No doubt in these cases the new and larger
breeds were generally introduced from foreign lands by
the immigration of new hordes of men. But it is not
probable that each larger breed, which in the course of
time supplanted a previous and smaller breed, was the
descendant of a distinct and larger species; it is far more
probable that the domestic races of our various animals
were gradually improved in different parts of the great
Europceo-Asiatic continent, and thence spread to other
countries. This fact of the gradual increase in size of
our domestic animals is all the more striking as certain
wild or half-wild animals, such as red-deer, aurochs,

8 'Die Pflanzen der Pfahlbauten,' 9 Morlot, ' Soc. Vaud. des Scien. Nat.,*

1865. Mars 1860, p. 298.

Chap, xxyiii. CONCLUDING REMARKS. 511

park-cattle, and boars,10 have within nearly the same
period decreased in size.

The conditions favourable to selection by man are,
— the closest attention being paid to every character, —
long-continued perseverance, — facility in matching or
separating animals, — and especially a large number being
kept, so that the inferior individuals may be freely re-
jected or destroyed, and the better ones preserved,
When many are Sept there will also be a greater chance
of the occurrence of well-marked deviations of structure.
Length of time is all-important; for as each character,
in order to become strongly pronounced, has to be aug-
mented by the selection of successive variations of the
same nature, this can only be effected during a long
series of generations. Length of time will, also, allow
any new feature to become fixed by the continued rejec-
tion of those individuals which revert or vary, and the
preservation of those which inherit the new character.
Hence, although some few animals have varied rapidly
in certain respects under new conditions of life, as dogs
in India and sheep in the "West Indies, yet all the ani-
mals and plants which have produced strongly marked
races were domesticated at an extremely remote epoch,
often before the dawn of history. As a consequence of
this, no record has been preserved of the origin of our
chief domestic breeds. Even at the present day new
strains or sub-breeds are formed so slowly that their
first appearance passes unnoticed. A man attends to
some particular character, or merely matches his ani-
mals with unusual care, and after a time a slight differ-
ence is perceived by his neighbours ; — the difference
goes on being augmented by unconscious and methodical
selection, until at last a new sub-breed is formed, receives
a local name, and spreads; but, by this time, its history
is almost forgotten. When the new breed has spread

10 Rutimeyer, 'Die Fauna der rfahlbauten,' ISO], s. 30.

512 CONCLUDING REMARKS. Chap. XXVIII.

widely, it gives rise to new strains and sub-breeds, and
the best of these succeed and spread, supplanting other
and older breeds ; and so always onwards in the march
of improvement.

When a well-marked breed has once been established,
if not supplanted by still improving sub-breeds, and if
not exposed to greatly changed conditions of life, induc-
ing further variability or reversion to long-lost characters,
it may apparently last for an enormous period. We may
infer that this is the case from the high antiquity of cer-
tain races ; but some caution is necessary on this head,
for the same variation may appear independently after
long intervals of time, or in distant places. We may
safely assume that this has occurred with the turnspit-
dog which is figured on the ancient Egyptian monu-
ments, with the solid-hoofed swine " mentioned by
Aristotle, with five-toed fowls described by Columella,
and certainly with the nectarine. The dogs represented
on the Egyptian monuments, about 2000 B.C., show us
that some of the chief breeds then existed, but it is
extremely doubful whether any are identically the same
with our present breeds. A great mastiff sculptured on
an Assyrian tomb, 640 B.C., is said to be the same with
the dog still imported into the same region from Thibet.
The true greyhound existed during the Roman classical
period. Coming down to a later period, we have seen
that, though most of the chief breeds of the pigeon
existed between two and three centuries ago, they have
not all retained to the present day exactly the same
character ; but this has occurred in certain cases in which
improvement was not desired, for instance in the case
of the Spot or the Indian ground-tumbler.

De Candolle 12 has fully discussed the antiquity of vari-
ous races of plants ; he states that the black-seeded pop-

» Godron, ' De l'Espece,' torn, i., 1859, p. 3C&
12 ' Geographie Botan.,' 1355, p. 989.

Cha*. xxyiii. CONCLUDING REMARKS. 5 1 3

py was known in the time of Homer, the white-seeded
sesamum by the ancient Egyptians, and almonds with
sweet and hitter kernels by the Hebrews ; but it does
not seem improbable that some of these varieties may
have been lost and reappeared. One variety of barley
and apparently one of wheat, botli of which were culti-
vated at an immensely remote period by the Lake-inha-
bitants of Switzerland, still exist. It is said 13 that
" specimens of a small variety of gourd which is still
" common in the market of Lima were exhumed from an
" ancient cemetery in Peru." De Candolle remarks that,
in the books and drawings of the sixteenth century, the
principal races of the cabbage, turnip, and gourd can be
recognised ; this might have been expected at so late a
period, but whether any of these plants are absolutely
identical with our present sub-varieties is not certain. It
is, however, said that the Brussels sprout, a variety which
in some places is liable to degeneration, has remained
genuine for more than four centuries in the district where
it is believed to have originated.14

In accordance with the views maintained by me in this
work and elsewhere, not only the various domestic races,
but the most distinct genera and orders within the same
great class, — for instance, whales, mice, birds, and fishes —
are all the descendants of one common progenitor, and
we must admit that the whole vast amount of difference
between these forms of life has primarily arisen from
simple variability. To consider the subject under this
point of view is enough to strike one dumb with amaze-
ment. But our amazement ought to be lessened when
we reflect that beings, almost infinite in number, during
an almost infinite lapse of time, have often had their
whole organisation rendered in some degree plastic, and

13 Pickering, ' Races of Man,' 1800, p. by a Deputation of the Caledonian Hist.
818. Soc, 1823, p. 293.

14 'Journal of a Horticultural Tour,'

514 CONCLUDING EEMARKS. Chap. XXJIIL

that each slight modification of structure which was in
any way beneficial under excessively complex conditions
of life, will have been preserved, whilst each which was in
any way injurious Avill have been rigoi-ously destroyed.
And the long-continued accumulation of beneficial varia-
tions will infallibly lead to structures as diversified, as beau-
tifully adapted for various purposes, and as excellently
co-ordinated, as we see in the animals and plants all around
us. Hence I have spoken of selection as the paramount
power, whether applied by man to the formation of do«
mestic breeds, or by nature to the production of species.
I may recur to the metaphor given in a former chapter:
if an architect were to rear a noble and commodious edi-
fice, without the use of cut stone, by selecting from the
fragments at the base of a precipice wedge-formed stones
for his arches, elongated stones for his lintels, and flat
stones for his roof, we should admire his skill and regard
him as the paramount power. Now, the fragments of
stone, though indispensable to the architect, bear to the
edifice built by him the same relation which the fluctuat-
ing variations of each organic being bear to the varied
and admirable structures ultimately acquired by its modi-
fied descendants.

Some authors have declared that natural selection ex-
plains nothing, unless the precise cause of each slight
individual difference be made clear. Now if it were ex-
plained to a savage utterly ignorant of the art of build-
ing, how the edifice had been raised stone upon stone,
and why wedge-formed fragments were used for the
arches, flat stones for the roof, &c. ; and if the use of
each part and of the whole building were pointed out, it
would be unreasonable if he declared that nothing had
been made clear to him, because the precise cause of the
shape of each fragment could not be given. But this is
a nearly parallel case with the objection that selection
explains nothing, because we know not the cause of each
individual difference in the structure of each beinsr.

Chap, xxviii. CONCLUDING REMARKS. 515

The shape of the fragments of stone fit the base of our
precipice may be called accidental, but this is not strictly
correct; for the shape of each depends on a long sequence
of events, all obeying natural laws; on the nature of the
rock, on the lines of deposition or cleavage, on the form
of the mountain which depends on its upheaval and sub-
sequent denudation, and lastly on the storm or earth-
quake which threAV down the fragments. But in regard
to the use to which the fragments maybe put, their shape
may be strictly said to be accidental. And here we are
led to face a great difficulty, in alluding to which I am
aware that I am travelling beyond my proper province.
An omniscient Creator must have foreseen every conse-
quence which results from the laws imposed by Him.
But can it be reasonably maintained that the Creator
intentionally ordered, if we use the words in any ordinary
sense, that certain fragments of rock should assume cer-
tain shapes so that the builder might erect his edifice?
If the various laws which have determined the shape of
each fragment were not predetermined for the builder's
sake, can it with any greater probability be maintained
that He specially ordained for the sake of the breeder
each of the innumerable variations in our domestic ani-
mals and plants ; — many of these variations being of no
service to man, and not beneficial, far more often injuri-
ous, to the creatures themselves ? Did He ordain that
the crop and tail-feathers of the pigeon should vary in
order that the fancier might make his grotesque pouter
and fantail breeds ? Did He cause the frame and mental
qualities of the dog to vary in order that a breed might
be formed of indomitable ferocity, with jaws fitted to pin
down the bull for man's brutal sport ? But if Ave give up
the principle in one case, — if Ave do not admit that the
variations of the primeval dog were intentionally guided
in order that the greyhound, for instance, that perfect
image of symmetry and vigour, might be formed, — no
shadoAV of reason can be assigned for the belief that

516 CONCLUDING REMARKS. Chap. XXVIII.

variations, alike in nature and the result of the same
general laws, which have been the groundwork through
natural selection of the formation of the most perfectly
adapted animals in the world, man included, were inten-
tionally and specially guided. However much we may
wish it, we can hardly follow Professor Asa Gray in his
belief "that variation has been led along certain benefi-
" cial lines," like a stream " along definite and useful lines
" of irrigation." If we assume that each particular
variation was from the beginning of all time preordained,
the plasticity of organisation, which leads to many injuri-
ous deviations of structure, as well as that redundant
power of reproduction which inevitably leads to a strug-
gle for existence, and, as a consequence, to the natural
selection or survival of the fittest, must appear to us
superfluous laws of nature. On the Other hand, an om-
nipotent and omniscient Creator ordains everything and
foresees everything. Thus we are brought face to face
with a difficulty as insoluble as is that of free will and
predestination.

INDEX.

Abbas Pacha, a fancier of fantailed pi-
scons, i. 251.

Abbet, Mr., on grafting, ii. 189; on
mignonette, ii. 287

Abbott, Mr. Keith, on the Persian
tumbler pigeon, i. 185.

Abbreviation of the facial bones, i.
94.

Abortion of organs, ii. 379-383, 475.

Absorption- of minority in crossed
races, ii. 111-113, 813.

Acclimatisation, ii. 367-379; of maize,
i. 387, 338.

Acerbi, pn the fertility of domestic
animals in Lapland, ii. 140.

AchalineBai ii. 71.

Achillea millefolium, bud variation in,
i. 490/

Aconitwn napeUus, roots of, innocuous
in cold climates, ii. 331.

Acorux calamus, sterility of. ii. 207.

Acosta. on fowls in South America at
its discovery, i. 288.

Acropera, number of seeds in. ii. 453.

Adam, Mr., ortein of OuUsus Adami, i.
469.

Adam. "W., on consanguineous mar-
riages, ii. 152.

Adams, Mr., on hereditary diseases,
ii. 16.

Advancement in scale of organisa-
tion, i. 19.

dSfftiops tH&coides, observations of
Fabre and Godron on, i. 377 : in-
creasing fertility of hybrids of, with
wheat, ii. 138.

jfiscnlmjlara and rubicunda, i. 470.

jEsculus p'lr'ri, tendency of, to be-
come double, ii. 205.

^BQbuta cynapwm, ii. 406.

Affinity, sexual elective, ii. 219.

Africa, white bull from, i. 115: feral
cattle in, i. 109 : food-plants of sava-
ges of. i. 371-372 : South, diversity
of breeds of cattle in. i. 103: West,
change in fleece of sheep in, i. 124.

Agare riripara, seeding of, in poor
soil. ii. 206.

Age. changes in trees dependent on, i.
461.

Agouti, fertility of, in captivity, ii.
186.

Agriculture, antiquity of, ii. 294.

Agrostis, seeds of, -used as food, i. 373,
373.

Aguara, i. 40.

Ainsworth, Mr., on the change in the
hair of animals at Angora, ii. 336.

Akbar Khan, his fondness for pigeons,
i. 247 ; ii. 250.

Alauda arvensis, ii. 189.

Albin, on " Golden Hamburgh" fowls,
i. 200 ; figure of the hook-billed duck,
i. .334.

Albinism, i. 139. ii. 28.

Albino, negro, attacked by insects, ii.
277.

Albinoes. heredity of. ii. 19.

Albinus, thickness of the epidermis
on the palms of the hands in man, ii.
358.

Alco, i. 45, ii. 128.

Aldrovandi. on rabbits, i. 131 : de-
scription of the nun pigeon, i. 192 ;
on the fondness of the Dutch for pi-
geons in the seventeenth century, i.
250 ; notice of several varieties of pi-
geons, i. 252-257 : on the breeds of
fowls, i. 299 ; on the origin of the do-
mestic duck, i. 335.

Alefield, Dr., on the varieties of
peas and their specific unity, i, 333 ;
on the varieties of beans, i. 397.

Alexander the" Great, his selection
of Indian cattle, ii. 245.

Algje. retrogressive metamorphosis
in, ii. 433 ; "division of zoospores of,
ii. 452.

Allen, W.. on feral fowls, i. 2S8; ii.
47.

Allman, Professor, on a monstrous
8axifraga geum, ii. 203. on the de-
velopment of the Hydroida, ii. 441.

Almond, i. 407; antiquity of, ii. 513;
bitter, not eaten by mice, ii. 281.

Alnus gluUnosa and incana, hybrids
of, ii. 161.

Alpaca, selection of. ii. 252.

Allium rosea, i. 454; ii. 135.

Amaryllis, ii. 172.

AmanjUh rittota, effect of foreign pol-
len on, i. 430.

Amaurosis, hereditary, ii. 18.

America, limits within which no use-

518

AMYGDALUS.

INDEX.

ful plants have been furnished by, i.
374 ; colours of feral horses in, i. 79,
80; North, native cultivated plants
of, i. 376 ; skin of feral pig from, i.
99; South, variations in cattle of, i.
112, 117.

Amygdalus persica, i. 496-414, 449.

Ammon, on the persistency of colour
in horses, ii. 33.

Anagrallis arvensis, ii. 231.

Analogous variation, i. 491, ii. 417-
423: in horses, i. 73; in the horse
and ass, i. S3; in fowls, i. 294-297.

Anas boschas, i. 334, ii. 56 ; skull of,
figured, i. 340.

Anas moschata, ii. 56.

"Ancon" sheep of Massachusetts, i.
128, ii. 129.

Andalusian fowls, i. 276.

Andalusian rabbits, i. 133.

Anderson, J., on the origin of British
sheep, i. 119; on tho selection of
qualities in cattle, ii. 237 ; on a one-
eared breed of rabbits, i. 135 ; on the
inheritance of characters from a one-
eared rabbit and three-legged bitch,
ii. 22 ; on the persistency of varieties
of peas, i. 397; on the production of
early peas by selection, ii. 243; on
the varieties of the potato, i. 398-399 ;
on crossing varieties of the melon, i.
479 ; on reversion in the barberry, i.
462.

Anderson, Mr., on the reproduction
of the weeping ash by seed, ii. 30 ;
on the cultivation of the tree paeony
in China, ii. 248.

Andersson, Mr., on the Damara, Be-
chuana, and Namaqua cattle, i. 112 ;
on the cows of the Damaras, ii. 362 ;
selection practised by the Damaras
and Namaquas, ii. 251 j on the use of
grass-seeds and the roots of reeds as
food in South Africa, i. 372.

Anemone Coronaria, doubled by selec-
tion, ii. 243.

Angina pectoris, hereditary, occur-
ring at a certain age, ii. 101.

Anglesea, cattle of, i. 103.

Angola sheep, i. 120.

Angora, change in hair of animals at,
ii. 330 ; cats of, i. 62, 64 ; rabbits of,
i. 134, 150.

Animals, Domestication of, facilitated
by fearlessness of man, i. 33 ; refu-
sal of wild, to breed in captivity, ii.
182 ; compound, individual peculiari-
ties of, reproduced by budding, i.
449 ; variation by selection in useful
qualities of, ii. 266.

Annual plants, rarity of bud-variation
in, i. 489.

Anomalies in the osteology of the
horse, i. 67.

Anomalous breeds of pigs, i. 97; of
cattle, i. 113.

Anser albifrons, characters of, repro-
duced in domestic geese, i. 347.

Anser cegyptiacus, i. 341 ; ii. 88.

Anser canadensis, ii. 192.

Anser cygnoides, i. 287.

Anser ferns, the original of the domes-
tic goose, i. 347 ; fertility of cross of,
with domestic goose, i. 347.

Anson, on feral fowls in the Ladrones,
i. 288.

Antagonism between growth and re-
production, ii. 460.

Anthemis «oMfc,bud-variation in flow-
ers of, i. 456 ; becomes single in poor
soil, ii. 204.

Antherozoids, apparent independ-
ence of, in algoe, ii. 459.

Anthers, contabescence of, ii. 202-203.

Antigua, cats of, i. 62 ; changed fleece
of sheep in, i. 124.

Antirrhinum mains, peloric, i. 440; ii.
78, 90, 203; double-flowered, ii. 204;
bud-variation in, i. 458.

Ants, individual recognition of, ii. 303.

Apes, anthropomorphous, ii. 153.

Aphides, attacking pear-trees, ii. 279 ;
development of, ii. 432-433.

Apoplexy, hereditary, occurring at a
certain age, ii. 100.

Apple, i. 419-421 ; fruit of, in Swiss
lake-dwellings, i. 382 ; rendered fas-
tigate by heat in India, i. 435; bud-
variation in the, i. 452 ; with dimi-
diate fruit, i. 471 ; with two kinds of
fruit on the same branch, i. 471 ; ar-
tificial fecundation of, i. 481 ; St. Va-
lery, i. 481 ; ii. 203 ; reversion in
seedlings of, ii. 45 ; crossing of varie-
ties of, ii. 160 ; growth of the, in Cey-
lon, ii. 334; Winter Majetin, not at-
tacked by coccus, ii. 280 ; flower-buds
of, attacked by bullfinches, ii. 280 ;
American, change of when grown in
England, ii. 332.

Apricot, i. 414-415 ; glands on the
leaves of, ii. 280; analogous varia-
tion in the, ii. 418.

Aqnila J'usca, copulating in captivity,
ii. 188.

Aquilegia vulgaris, i. 439 ; ii. 397.

Arab boarhound, described by Har-
court, i. 30.

Arabis blepJearaphyUa and A. Soyeri,
effects of crossing, i. 481.

Arcdia trifoliata, bnd-variation in
leaves of,' i. 459.

Araucarias, young, variable resist-
ance of, to frost, ii. 372.

Archangel pigeon, ii. 290.

Arctic regions, variability of plants
and shells of, ii. 309.

Aria testita, grafted on thorns, i. 461.

Aristophanes, fowls mentioned by, i. ■
298.

Aristotle, on solid-hoofed pigs, i. 96 :
domestic duck unknown to, i. 335 ;
on the assumption of male characters
by old hens, ii. 68.

Arni, domestication of the, i. 105.

Arrest of development, ii. 379-382.

Arteries, increase of anastomosing
branches of, when tied, ii. 230.

INDEX.

519

Aru island;?, wild pig of. i. 8?.
Arum. Polynesian varieties of. ii. 309.

is, number of eggs of, ii. 453.
ASH, varieties of the, i. 434; weeping,
i. -135: simple-leaved, i. 136; bud-
variatiou in. i. 459: effects of graft
upon the stock in the, i. 473: pro-
duction of the blotched Breadalbane,
ibid. : weeping, capricious repro-
duction of. by seed. ii. 30.
AMnits Burckeuii, i. 83.
Asinus hemionus, ii. 59.
Asinus indicus, ii. 5S-59, 65.
Asinus guagga, i. 88.
Asinus tcemopus, ii. 51 : the original of

the domestic ass, i. 81.
Asparagus, increased fertility of culti-
vated, ii. 141.
Ass, early domestication of the, i. 81 ;
breeds of ibid. ; small size of, in
India, 5. Si ; stripes of. i. 82 : ii. 421 ;
dislike of to cross water, i. 223: re-
version in, ii. 57-59, 64; hybrid of
the, with mare and zebra, ii. 58;
prepotency of the, over the horse,
ii. l;S: crossed with wild ass, ii. 250;
variation and selection of the. ii.
286.
Assyrian sculpture of a mastiff", i. 23.
Asters, ii. 31. 880.
Astiima, hereditary, ii. 17, 101.
Atavism. See Reversion.
Athelstan. his care of horses, ii. 240.
Atkinson. Mr., on the sterility of the
Tarroo silk-moth in confinement, ii.
193.
Aubergine, ii. 115.
Audubon, on feral hybrid ducks, i.
233 ; ii. 02 ; on the domestication of
wild ducks on the Mississippi, i. 335 ;
on the wild cock turkey visiting do-
mestic hens, i. 353: fertility of Irrin-
oiUa (Aria in captivity, ii. 189; fertil-
ity of Golumba miqratoria and leu-
cocephaia in captivity, ii. 190 ; breed-
ing of Anser canadensis in captivity,
ii. 192.
Audubon and Bachman, on the change
of coat in Oris Montana, i. 125;
sterility of Sciurus dnerea in con-
finement, ii. 187.
Auricula, effect of seasonal condi-
tions on the, ii. 330 ; blooming of, ii.
416.
Au>tralia, no generally useful plants
derived from, i. 374 : useful plants
of, enumerated by Hooker, i. 375.
AUSTRIA, heredity of character in em-
perors of, ii. 85.
Autexrieth, on persistency of colour

in horses, ii. 33.
Ava, horses of, i. 71.
At n ifatua, eultivability of, i. 377.
Aveen Akbery. pigeons mentioned

in the, i. ISO. 192, 227. 250, 253.
Ayres, \V. P.. on bud-variation in

pelargoniums, i. 454.
Azalea indica, bud-variation in. i. 453.
Azaua, ou the feral do^s of La Plata,

i. 41 ; on the crossing of domestic
with wild cats in Paraguay, i. 61 ;
on hornlike processes in horses, i.
67 ; on curled hair in horses, i. 71 ;
ii. 248, 392; on the colours of feral
horses, i. 79-SO; ii. 312; on the
cattle of Paraguay and La Plata, i.
100. 109, 113; ii. 312: on a hornless
bull. ii. 249; on the increase of cat-
tle in South America, ii. 148 ; on the
growth of horns in the hornless cat-
tle of Corrientes, ii. 54; on the "Ni-
ata" cattle, i. 114; on naked quad-
rupeds, ii. 330 ; on a race of black-
skinned fowls in South America, i.
312: ii. 254; on a variety of maize,
i. 387.

Babington, C. C, on the origin of
the plum, i. 415 ; British species of
the genus Rosa, i. 441 ; distinctness
of Viola /idea and tricolor, i. 443.

Baciimann, Mr., on the turkey, ii.
316. See also Audubon.

Badger, breeding in confinement, ii.
186.

" Bagadotten-Taube," i. 175.

Baily, Mr., on the effect of selection
on fowls, ii 210 ; on Dorking fowls,
ii. 287.

Baird, S., on the origin of the turkey,
i. 352.

Baker, Mr., on heredity in the horse,
ii. 20; on the degeneration of the
horse by neglect, ii. 289; orders of
Henrys VII. and VIII- for the de-
struction of undersized mares, ii.
246. •

Bakewell, change in the sheep effect-
ed by, ii. 240.

Balancement, ii. 411-413 ; of growth,
law of, 331.

Baldhead, pigeon, i. 186.

Baldness, in man, inherited, ii. 95;
with deficiency in teeth, ii. 394-395.

Ballance, Mr., on the effects of in-
terbreeding on fowls, ii. 155 ; on
variation in the eggs of fowls, i. 300.

BaUola nigra, transmission of varie-
gated leaves in, i. 460.

Bamboo, varieties of the, ii. 309.

Banana, variation of the, i. 447 ; ii.
309 ; bud-variation in the, i. 453 ;
sterility of the, ii. 323.

Bantam fowls, i. 27S; Sebright, ori-
gin of, ii. 121 ; sterility of. ii. 127.

Barb (Pigeon), i. 179-181, 2.50; ii. 274;
figure of, i. 180 ; figure of lower jaw
of, i. 202.

Barbs, of wheat, i. 378.

Barberry, dark or red-leaved variety,
i. 435 ; ii. 31 ; reversion in suckers
of seedless variety, i. 462.

Barbut, J., on the dogs of Guinea, i.
39 ; on the domestic pigeons in Gui-
nea, i. 228 ; fowl, not native in Gui-
nea, i. 288.

Barking, acquisition of the habit of,
by various dogs, i. 41.

520

INDEX.

Barley, wild, i. 3TT ; of the lake-dwel-
lings, i. 384 ; ancient variety of, ii.
513.

Barnes, Mr., production of early peas
by selection, ii. 213.

Barnet, Mr., on the intercrossing of
strawberries, i. 423; dicecioushess
of the Hautbois strawberry, i. 425 ;
on the scarlet American strawberry,
ii. 212.

Bartii, Dr., use of grass-seeds as food
in Central Africa,!. 372.

Bartlett, A. D., on the origin of
" Himalayan " rabbits by intercross-
ing, i. 137 ; on the feral rabbits of
Porto Santo, i. 143, 144; on geese
with reversed feathers on the'head
tind neck, i. 348 ; "on the young of
the black-shouldered peacock, i.350 ;
on the breeding of the Felidre in cap-

: tivity, ii. 185.

Bartram, on the black wolf-dog of
Florida, i. 36.

Bates, H. W., refusal of wild animals
to breed in captivity, ii. 184, 187;
sterility of American monkeys in
captivity, ii. 187; sterility of tamed
guans, ii. 191.

Batrachia, regeneration of lost parts
in, ii. 26.

Beach, raised, in Peru, containing
heads of maize, i. 386.

Beak, variability of, in fowls, i. 312 ;
individual differences of, in pigeons,
i. 197 ; correlation of, with the feet
in pigeons, i. 211-215.

Beale, Lionel, on the contents of
cells, ii. 443; on the multiplication
of infectious atoms, ii. 452 ; on the
origin of fibres, ii. 457.

Beans, i. 397 ; of Swiss lake-dwellings,
i. 385 ; varieties of, produced by se-
lection, ii. 264 ; French and scarlet,
variable resistance of to frost, ii.
372,378 ; superiority of native seed of.
ii. 378; a symmetrical variation of
scarlet, ii. 388 ; experiments on kid-
ney, i. 397 ; with monstrous stipules
and abortive leaflets, ii. 412.

Beard, pigeon, i. 186.

Bears, breeding in captivity, ii. 186.

Beaslet, J., reversion in crossed cat-
tle, ii. 56.

Beaton, D., effect of soil upon straw-
berries, i. 426; on varieties of pelar-
gonium, i. 438; ii. 330, 37-4; bud-
variation in Gladiolus col rillii, i. 459;
cross between Scotch kail and cab-
bage, ii. 123; hybrid gladiolus, ii.
172; constant occurrence of new
forms among seedlings, ii. 284 ; on
the doubling of the composite, ii.
380.

Bechuana cattle, i. 112.

Beck, Mr., constitutional differences
in pelargoniums, i. 438.

Beckmann, on changes in the odours
of plants, ii. 331.

Bechstein, on the burrowing of

wolves, i. 41: "Spitz" dog, i. 45;
origin of the Newfoundland dog, i.
58; crossing of domestic and wild
swine, i. 87 ; on the Jacobin pigeon,
i. 190, 254; notice of swallow-pi-
geons, i. 193; on a fork-tailed pi-
geon, i. 193 ; variations in the colour
of the croup in pigeons, i. 226 ; on
the German dove-cot pigeon, i. 227 ;
fertility of mongrel pigeons, i. 335 ;
on hybrid turtle-doves, i. 236 ; on
crossing the pigeon with Colvmba
anas, V. palumous, Turtw risoHa.
and T. vulgaris, i. 236 ; development
of spurs in the silk-hen, i. 309 ; on
Polish fowls, i. 310, 319 ; on crested
birds, i. 310; on the Canary-bird, i.
356 ; ii. 33, 197 ; German superstition
about the turkey, i. 354 ; occurrence
of horns in hornless breeds of sheep,
ii. 43; hybrids of the horse and ass,
ii. 88; crosses of tailless fowls, ii.
117 ; difficulty of pairing dove-cot
and fancy pigeons, ii. 130; fertility
of tame ferrets and rabbits, ii. 140 ;
fertility of wild sow, ibid. ; difficulty
of breeding caged birds, ii. 189;
comparative fertility of Psittacus eri-
thacus in captivity, ii. 190 ; on chang-
es of plumage in captivity, ii. 193 ;
liability of light-coloured cattle to
the attacks of flies, ii. 277 ; want of
exercise a cause of variability, ii.
310 ; effect of privation of light upon
the plumage of birds, ii. 333; on a
sub-variety of the monk-pigeon, ii.
420.

Beddoe, Dr., correlation of com-
plexion with consumption, ii. 403.

Bedeguar gall, ii. 342.

Bee, persistency of character of, ii.
307 ; intercrossing, ii. 157 ; convey-
ance of pollen of peas by, i. 397.

Bee-Ophrys, self-fertilisation of, ii.
115.

Beech, dark-leaved, i. 435, ii. 31 ; fern-
leaved, reversion of, i. 459; weep-
ing, non-production of by seed, ii.
30.

Beechey, horses of Loochoo Islands,
i. 71.

Beet, i. 326 ; increase of sugar in, by
selection, ii. 243.

Begonia frigida, singular variety of,
i. 440 ; 'sterility of, ii. 203.

Belgian rabbit, i. 134.

Bell, T., statement that white cattle
have coloured ears, i. 109.

Bell, W., bud-variation in Cisfus trt-
cu.yris, i. 454.

Bellingeri, observations on gesta-
tion in the dog, i. 44 j on the fertil-
ity of dogs and cats, ii. 140.

Belon, on high-flying pigeons in Paph-
lagonia, i. 255 ; varieties of the goose,
i.349.

Benguela, cattle of, i. 112.

Bennett, Dr. G., pigs of the Pacific
islands, i. 91, ii. Ill ; dogs of the Pa-

INDEX.

121

cific isiand?. ii. Ill ; varieties of
cultivated plant* in Tahiti, ii. 309.

Bennett, Mr., on the fallow deer. ii.
189.

Dkntiiam, G.j number and origin of
cultivated plants, i. 989 : cereals all
cultivated varieties, i. 377 : species
of the orange group, i. 403 ; distinc-
tions of almond and peach, i. 407 ;
British species of Bosa, i. 441 ; iden-
tity of Viola l"t<<t and tricolor, i. 413.

Berberis vulgaris, i. 463, ii. 31.

Berberis fVallichii, indifference of, to
climate, ii. 200.

Berjean, on the history of the dog, i.
29, 30.

Berkeley, G. F., production of hen-
cocks in a strain of game-fowls, i. 300.

Berkeley, M. J., crossing of varie-
ties of the pea, i. 477 ; effect of for-
eign pollen on grapes, i. 480 ; on hy-
brid plants, ii. 102 ; analogy between
pollen of highly-cultivated plants and
hybrids, ii. 323 ; on Hungarian kid-
ney-beans, ii. 339 : failure of Indian
wheat in England, ii. 370: bud de-
veloped on the petal of a Clcakia, ii.
450.

Bernard, inheritance of disease in
the horse, ii. 20.

Bernard. C. independence of the or-
gans of the body, ii. 441-142 : special
affinities of the tissues, ii. 465.

Bernhardt varieties of plants with
laciniated leaves, ii. 418.

Bern&da antarctica, i. 348.

Bertero, on feral pigeons in Juan
Fernandez, i. 233.

Betula alba, ii. 29.

Bewick, on the British wild cattle, i.
108.

Bible, reference to breeding studs of
horses in, i. 72 : references to do-
mestic pigeons in the, i. 249 ; indica-
tions of selection of sheep in the, ii.
244 ; notice of mules in the, ii. 244.

Bidwell. Mr., on self-impotence in
Amaryllis, ii. 172.

Birch, weeping, i. 404, ii. 29.

Birch, Dr. S., on the ancient domesti-
cation of tho pigeon in Egypt, i. 249 :
notice of bantam fowls in a Japanese
encyclopaedia, i. 278. 299.

Birch, Wyrley, on silver-grey rabbits,
i. 137-138.

Birds, sterility caused in, by change
of conditions, ii. 188-192.

Bladder-nut, tendency of the, to be-
come double, ii. 205.

Blaine. Mr., on wry-legged terriers,
ii. 296.

Blainville, origin and history of the
dog, i. 28 ; variations in the number
of teeth in doirs. i. 40 ; variations in
the number of toes in dogs, i. 50 ;
on mummies of cats. i. 00 ; on the
osteology of solid-hoofed pigs, i. 97 ;
on feral Patagonian and X. American
pigs, i. 99.

11 Blass-Tafbe." i. 192.

Bleedixi;. hereditary, ii. 16, 17; sex-
ual limitation of excessive, ii. 94.

Blending of crossed races, time occu-
pied by the, ii. 110.

Blindxess, hereditary, ii. 18; at a
certain age. ii. 100 : associated with
colour ef hair. ii. 895.

Bloodikhnds. defeneration of, caused
by interbreeding, ii. 150.

Blumexbacii, on the protuberance of
the skull in Polish fowls, i. 310; on
the effect of circumcision, ii 85 ; in-
heritance of a crooked finger, ii. 86 :
on badger-dogs and other varieties
of the "dog. ii. 200 ; on Hydra, ii.
354 ; on the "nisus formatlvus," ii.
355.

Blyth, E., on the Pariah dog, i. OS ;
hybrids of dog and jackal, i. 4ii ;
early domestication of cats in India,
i. 59 ; origin of domestic cat, i. 60 ;
crossing of domestic and wild cats,
ib. ; on Jiidian cats resembling Fe-
Us ehatlSji. 62 ; on striped Burmese
ponies, i. 77 ; on the stripes of the
ass, i. 83 ; on Indian wild pigs. i. S7 ;
on humped cattle, i. 102 ; occurrence
of i>V.N //w. ',,.,„* in Irish crannoges,
i. 105 ; fertile crossing of zebus and
common cattle, i. 100 ^ on the species
of sheep, i. 119 ; on the fat-tailed In-
dian sheep, i. 121 ; origin of the
goat, i. 138 ; on rabbits breeding in
India, i. 140 ; number of tail-feathers
in fantails, i. 181 ; Lotan tumbler
pigeons, i. ISO; number of tail-feath-
ers in Ectophh's, i. 100; on Cohcmba
afflf&S, i. 22.5 : pigeons roosting in
trees, i. 222 ; on Oolumba leuconota.
i. 224; on Gc&wmba intermedia of
Strickland, i. 226 ; variation in col-
our of croup in pigeons, i. 226-227,
240; voluntary domestication of rock-
pigeons in India, i. 227 ; feral pigeons
on the Hudson, i. 233 ; occurrence
of sub-species of pigeons, i. 240 ; no-
tice of pigeon-fanciers in Delhi, &c,
i. 250; hybrids of Gallw Sonneralit
and the domestic hen, i. 383 ; sup-
posed hybridity of (faults Temminc-
Aii, i. 284 ; variations and domestica-
tion of OaUvsbanhxoa, i. 385-386, 2S7 ;
crossing of wild and tame fowls in
Burmah. i. 386 ; restricted range of
the larger gallinaceous birds, i. 287 ;
feral fowls in the Nicobar islands, i.
288 ; black-skinned fowls occurring
near Calcutta, i. 310 : weight of QaX-
/'/-■ hiiitk'ira. i. 329 ; degeneration of
the turkey in India, i. 355, ii. 335 ;
on the colour of gold-fish, i. 357 ; on
the Ghor-Khur (Asinus mdicus), ii.
58; 0nAHnwhemiO7ius,il.&9: num-
ber of eggs of OaBus bankiva, ii.
140 : on the breeding of birds in cap-
tivity, ii. 102; co-existence of large
and small breeds in the same coun-
try, ii. 330 ; on the drooping cars of

522

EOETHIUS.

INDEX.

the -elephant, ii. 363; homology of
leg and wing feathers, ii. 388.

Boethius on Scotch wild cattle, i.
108.

Boitard and Corbie, on the breeds of
pigeons, i. 164 ; Lille pouter pigeon,
i. 172 ; notice of a gliding pigeon, i.
193 ; variety of the pouter pigeon, i.
200 ; dove-cot piseon, i. 227 ; cross-
ing pigeons, i. 235-236, ii. 123, 156 ;
sterility of hybrids of turtle-doves,
i. 236 ; reversion of crossed pigeons,
i. 241, ii. 55 ; on the fantail, i. 254, ii.
86 ; on the trumpeter, ii. 86 ; prepo-
tency of transmission in silky fan-
tail, ii. 87, 89; secondary sexual
characters in pigeons, ii. 95 ; cross-
ing of white and coloured turtle-
doves, ii. 117 ; fertility of pigeons,
ii. 140.

Bombtcid^b, wingless females of, ii.
360.

Bombyx hesperus, ii. 366.

Bombyx Hutloni, i. 364.

Bombyx mori, i. 362-367.

Bonaeous, on maize, i. 3S6, 387.

Bonaparte, number of species of Co-
lumbidse, i. 165 ; number of tail-
feathers in pigeons, i. 196 ; size of
the feet in Columbidce, i. 214; on
Columba guinea, i. 224 ; Columba
turricola, rupestris, and Schimperi,
i. 225.

Bonatea speciosa, development of ov-
ary of, i. 484.

Bonavia, Dr., growth of cauliflowers
in India, ii. 374.

Bones, removal of portions of, ii.
356 ; regeneration of, ii. 354 ; growth
and repair of, ii. 457.

Bonnet, on the salamander, ii. 26,
409, 430, 461 ; theory of reproduc-
tion, ii. 461.

Borchmeter, experiments with the
seeds of the weeping ash, ii. 30.

Borecole, i. 389.

Borelli, on Polish fowls, i. 299.

Borneo, fowls of, with tail-bands, i.
284.

Bornet, E., condition of the ovary in
hybrid Cisfi, i. 467 ; self-impotence
of hybrid Cisti, ii. 173.

Borrow, G., on pointers, i. 58.

Bort de Saint-Vincent, on gold-fish,
i. 358.

Bos, probable origin of European do-
mestic cattle from three species of,
i. 106.

Bos frontosus, i. 102, 104-105.

Bos'indicm,i. 101.

Bos longifrons, i. 102, 104.

Bos primigenius, i. 102, 103-104, ii. 149.

Bos sondaicus, ii. 250.

Bos taunts, i. 101.

Bos trochoceros, i. 104.

Bosc, heredity in foliage-varieties of
the elm, i. 436.

Bosse, production of double flowers
from old seed, ii. 204.

Bossi, on breeding dark-coloured silk-
worms, i. 364.

Bouchardat, on the vine disease, i.
402.

Boudin, on local diseases, ii. 333 ; re-
sistance to cold of dark-complex-
ioned men, ii. 404.

" Boulans," i. 171.

" Bouton d'Alep," ii. 333.

Bowen, Prof.-, doubts as to the impor-
tance of inheritance, ii. 11.

Bowman, Mr., hereditary peculiari-
ties in the human eye, ii. 17-19 ;
hereditary cataract, ii. 102.

Brace, Mr., on Hungarian cattle, i.
103.

Brachycome iberidifolia, ii. 315.

Bracts, unusual development of, in
gooseberries, i. 428.

Bradley, Mr., effect of grafts upon
the stock in the ash, i. 473 ; effect of
foreign pollen upon apples, i. 481 ;
on change of soil, ii. 179.

" Brahma Pootras," a new breed of
fowls, i. 297.

Brain, proportion of, in hares and
rabbits, i. 158-161.

Brandt, origin of the goat, i. 127.

Brassica, varieties of, with enlarged
stems, ii. 418.

Brassica asperifolia, ii. 412.

Brassica napus, i. 392.

Brassica oleracea, i. 389.

Brassica rapa, i. 392, ii. 201.

Braun, A., bud-variation in the vine,
i. 451 ; in the currant, i. 452 ; in
MirabUis jalapa, i. 459 ; in Cytisus
adami, i. 465 ; on reversion in the
foliage of trees, i. 459 ; spontaneous
production of Cytisus purpureo-elon-
gatus, i. 468 ; reversion of flowers
by stripes and blotches, ii. 52 ; ex-
cess of nourishment a source of va-
riability, ii. 310.

Brazil, cattle of, i. 113.

Bread-fruit, varieties of, ii. 309 ; ste-
rility and variability of, ii. 323.

Bree, W. T., bud-variation, in Gera-
nium pratense and Oentaurea cya-
nus, i. 455 ; by tubers in the dahlia, i.
462 ; on the deafness of white cats
with blue eyes, ii. 396.

Breeding, high, dependent on inheri-
tance, ii. 11-12.

Breeds, domestic, persistency of, ii.
297, 512-513 ; artificial and natural,
ii. 494-495 ; extinction of, ii. 508 ; of
domestic cats, i. 61-64 ; of pigs pro-
duced by crossing, i. 101 ; of cattle,
i. 110-111, 115-118; of goats, i. 128.

Brehm, on Columba amalice, i. 225.

Brent, B. P., number of mamnue in
rabbits, i. 134 ; habits of the tumbler
pigeon, i. 187 ; Laugher pigeon, i.
191 ; coloring of the kite tumbler, i.
198 ; crossing of the pigeon with Co-
lumba cvnas,\ 236 ; mongrels of the
trumpeter pigeon, ii. 86 ; close inter-
breeding of pigeons, ii. 156; opinion

BRICKELL.

INDEX.

523

on Aldrovandi*s fowls, i. 299; on
stripes in chickens, i. 302: on the
combs of fowls, i. 306; double-spur-
red Dorking fowls, i. 808 : effect of
crossing on colour of plumage in
fowls. i. 311: incubatory instinct of
mongrels between non-sittins varie-
ties of fowls, ii. 60: origin ofthe do-
mestic duck. L 334: fertility of the
hook-billed duck. ibid. ; occurrence
of the plumage of the wild duck in
domestic breeds, i. 333; voice of
ducks, i. 340; occurrence of a short
upper mandible in crosses of hook-
billed and common ducks, i. 339; re-
version in ducks produced by cross-
ing, ii. 56; variation ofthe canary-
bird, i. 356 : fashion in the canary,
ii. 293 ; hybrids of canary and finch-
es, ii. 02.

Brickell. on raising nectarines from
seed, i. 409 ; on the horses of North
Carolina, ii. 362.

Bridges. Mr., on the dogs of Tierra
del FuegO, i. 55 : on the selection of
dogs by the Fuegians, ii. 250.

Bhidgman. W. K., reproduction of ab-
normal ferns, i. 4(50. ii. 454.

Briggs, J. J., regeneration of portions
ofthe fins of fishes, ii. 26.

Broca, P., on the intercrossing of
dogs, i. 45, 46 ; on hybrids of hare and
rabbit, i. 133 : on the rumpless fowl,
i. 313 : nn the character of half-castes,
ii. 63 ; degree of fertility of mongrels.
ii. 126 ; sterility of descendants of
wild animals bred in captivity, ii.
195.

Broccoli, i. 390 : rudimentary flowers
in. ii. 380 : tenderness of, ii. 373.

Bromehead. \Y\. loublins of the Can-
terbury bell bj- selection, ii. 243.

Bromfield, Dr., sterility of the ivy
and A '-. ii. 207.

L 378.

Bronx, H. G., bud-variation in An-
.'•■. i. 456; effects of cross-breed-
ing on the female, i. 485 ; on hered-
ity in a one-horned cow, ii. 22 ; pro-
pagation of a pendulous peach by
seed. ii. 29 ; absorption of the minor-
ity in crossed races, ii. Ill ; on the
crossing of horses, ii. 117; fertility
of tame rabbits and sheep, ii. 139-
140 ; changes of plumage in captivi-
ty, ii. 193; on the dahlia, ii. 315.

Bronze period, dog of. i. 31.

Brown. C. variations in the dentition
of the horse, i. 67.

Brown-Seqvai:d. Dr., inheritance of
artificially-produced epilepsy in the
guinea-pig, ii. 36.

Brunswigia, ii. 172.

Brussels Sprouts, i. 389, ii. 513

Bubo maxttnus, ii. 189.

Buckland, F., on oysters, ii. 838;
number of eggs in a codfish, ii. 463.

Buckle. Mr., doubts as to the import-
ance of inheritance, ii. 11.

BUCKLEY, Miss, carrier pigeons roost-
ing in trees, i. 222.

Brt kman. Prof., cultivation of Avoid)
fat mi. i. 377: cultivation of the wild
parsnip, i. 392. ii. 213. 335 ; reversion
in the parsnip, ii. 45.

Buckwheat, injurious to white pigs,
when in flower, ii. 405.

Bud and seed, close analogy of, i. 193.

BUD-REVERSION, ii. 51.

BOSS, adventitious, ii. 4.71.

Bid-variation, i. Us- 194. ii. 307, 347-
348. 851 : contrasted with seminal re-
production, i. 44s ; peculiar to plants,
i. 449: in the peach, i. 410. 450: in
plums, i. 450 : in the cherry, i. 451 ;
in grapes, tind. ; in the gooseberry,
currant, pear, and apple, i. 451-452;
in the banana, camellia, hawthorn,
Azalea indica, and < istvs tri
i. 453-454 ; in the hollyhock and pe-
largonium, i. 4.54: in Qercmivmpra-
(■ n u and the chrysanthemum, i. 455 ;
in roses, i. 442. 466-458; in sweet
■williams. carnations, pinks, stocks,
and snapdragons, i. 458 ; in wall-
flowers, cyclamen, QSnowera bien-
h'x. <,>:ii!b>hi< colcitlii, fuchsias, and
Mirabilis jalajMy i. 458-459; in foli-
age of various trees, i. 459-401 : in
cryptogamic plants, i. 460 ; by suck-
ers in Phlox and barberry, i. 461-462 ;
by tubers in the potato, i. 462 : in the
dahlia, ibid. ; by bulbs in hyacinths,
ImatophyUvm miniatum, and tulips,
i. 463: in Tif/ridia conchiflora. ibid. :
in HemeroeoMs, ibid.; doubtful
cases, i. 404 : in ( ytisus Adatni, i. 465-
473 : probable in jEscidw rubiatndo,
i. 470; summary of observations on,
i. 486.

Buffon, on crossing the wolf and dog,
i. 46 ; increase of fertility by domes-
tication, ii. 139 : improvement of
plants by unconscious selection, ii.
260 ; theory of reproduction, ii. 449.

Bviimus, ii. 71.

Bull, apparent influence of, on off-
spring, ii. S9.

Bullace, i. 415.

Bulldog, recent modifications of, i.
58.

Bullfinch, breeding in captivity, ii.
189; attacking flower-buds, ii. 280.

Bult, Mr., selection of pouter pigeons,
ii. 239.

" BUNDTNERSCHWEEN." i. 88.

Bunting, reed, in captivity, ii. 193.
Burdach, crossing of domestic and

wild animals, i. S7 ; aversion of the

wild boar to barley, ii. 365.
Burke. Mr., inheritance in the horse,

ii. 19.
Burlingtonia, ii. 107.
Burmaii. eats of. i. 64.
Burmese ponies, striped, i. 77.
BritNEs. Sir A., on the Karakool

sheep, i. 124, ii. 336 : varieties of the

vine in Cabool, i. 401 ; hawks trained

t) J-i BURTON CONSTABLE. INDEX.

in Scinde, ii. 188 ; pomegranates pro-
ducing seed, ii. 205.

Burton Constable, wild cattle at, i.
108.

" Burzel-Tauben," i. 184.

Bussorah carrier, i. 175.

Buteo vulgaris, copulation of, in cap-
tivity, ii. 188.

Butterflies, polymorphic, ii. 478.

Buzareingues, Girou de, inheritance
of tricks, ii. 15.

Cabanis, pears grafted on the quince,
ii. 312.

Cabbage, i. 389-392; varieties of, i.
389 ; unity of character in flowers
and seeds of, i. 3S9-390 ; cultivated
by ancient Celts, i. 390 •; classification
of varieties of, ibid. ; ready crossing
of, i. 391. ii. 115, 123, 101 ; origin of,
i. 391 ; increased fertility of,~when
cultivated, ii. 141 ; growth of, in tro-
pical countries, ii. 334.

Cabool, vines of, i. 401.

Cabral, on early cultivation in Bra-
zil, i. 370.

Cactus, growth of cochineal on, in
India, ii. 332.

Cjesar, Bos pHmigenius wild in Eu-
rope in the time of, i. 104; notice of
fowls in Britain, i. 298; notice of
the importation of horses by the
Celts, ii. 245.

Caffre fowls, i. 278.

Caffres, different kinds of cattle pos-
sessed by the, i. 112.

"Cagias," a breed of sheep, i. 121.

Calceolarias, i. 438; ii. 180; effects
of seasonal conditions on, ii. 330 ; pe-
loric flowers in, ii. 415.

" Calongos,1' a Columbian breed of
cattle, i. 113.

Calver, Mr., on a seedling peach pro-
ducing both peaches and nectarines,
i. 411.

Calyx, segments of the, converted in-
to carpels, ii. 469.

Camel, its dislike to crossing water,
i. 223.

Camellia, bud-variations in, i. 453; re-
cognition of varieties of, ii. 303 ; va-
riety in hardness of, ii. 371.

Cameron, D., on the cultivation of
Alpine plants, ii. 199.

Cameronn, Baron, value of English
blood in race-horses, ii. 21.

Campanula medium, ii. 243.

Canary-bird, i. 355-356; conditions
of inheritance in, ii. 33 ; hybrids of,
ii. 62 ; period of perfect plumage in
ii. 99 ; diminished fertility of, ii. 197
standard of perfection in, ii. 237
analogous variation in, ii. 419.

Cancer, heredity of, ii. 10, 17, 102.

Canine teeth, development of the, in
mares, ii. 382.

Canis alopex, i. 43.

Cants antarcticm, i. 33.

Canis argentatus, ii. 185.

Canis aureus, i. 43.

Canis canorivorus, domesticated and

crossed in Guiana, i. 36.
Canis rim lYo-i aiitgatm, i. 43.
Canis fulvus, i. 43.
Canis Ingce, the naked Peruvian dog,

i. 37.
Canis latrans, resemblance of, to the
Hare Indian dog, i. 35 ; one of the
original stocks, i. 39.
Canis htpaster,\. 38.
Canis lupus, var. occidentalis, resem-
blance of, to North American dogs,
i. 34; crossed with dogs, i. 36; one
of the original stocks, i. 39.
Canis mesomelas, i. 39, 43.
Canis primcevus, tamed by Mr. Hodg-
son, i. 40.
Canis sabbar, i. 38.
Canis simerms: possible original of

greyhounds, i. 48.
Canis thaleb, i. 43.

Canis variegatus, i. 43.

Canterbury Bell, doubled by selec-
tion, ii. 243.

Cape of Good Hope, different kinds of
cattle at the, i. 112 ; no useful plants
derived from the, i. 374.

Capercailzie, breeding in captivity,
ii. 191.

Copra cegagrus and C. Falconeri, pro-
bable parents of domestic goat, i.
127.

Capsicum, i. 447.

Cardan, on a variety of the walnut, i.
429 ; on grafted walnuts, ii. 313.

Cardoon, ii. 48.

Carex rigida, local sterility of the, ii.
207.

Carlier, early selection of sheep, ii.
247.

Carlisle, Sir A., inheritance of pecu-
liarities, ii. 15, 17 ; of polydactylism,
ii. 24.

" Carme" pigeon, i. 193.

Carnation, "bud-variation in, i. 458;
variability of, i. 445; striped, pro-
duced by crossing red and white, i.
472 ; effect of conditions of life on
the, ii. 329.

Carnivora, general fertility of, in cap-
tivity, ii. 185.

Caroline Archipelago, cats of, i. 64.

Carp, ii. 285.

Carpels, variation of, in cultivated
cucurbitacea?, i. 432.

Carpenter, W. B., regeneration of
bone, ii. 354 ; production of double
monsters, ii. 408; number of eggs in
an Ascaris, ii. 453.

Carpinus be.lulus, i. 436.

Carpopha.ga Uttoralis and luctuosa, i.
224.

Carrier pigeon, i. 173-176 ; English, i.
173; figured, i. 174; skull figured, i.
201 ; history of the, i. 257 ; Persian,
i. 174 ; Bussorah, ibid. ; Bagadot-
ten, skull figured, i. 201 ; lower jaw
figured, i. 203.

CARRIERE.

INDEX.

:v2r)

Caeriere, cultivation of the wild cor-
rot, i. 302; intermediate form be-
tween llif almond and the peach, i.
408; glands of peach-leaves, i. 413;
bud-variation in the vine. i. 451 ;
grafts of A i in vestita upon thorns, i.
4ii.j : variability of hybrids of Ery-
tlii'um, ii. 820.

Carrot, wild, effects of cultivation on
the, i. 898; reversion in the, ii. 45;
run wild, ii. 48 ; increased fertility of
cultivated, ii. 1 11 ; experiments on
the. ii. 335 : acclimatisation of the,
in India, ii. 374.

Carthamw, abortion of the pappus in,
ii. 881.

Cartier, cultivation of native plants
in Canada, i. 376.

Caryophyllace-e, frequency of con-
tabescence in the. ii. 202.

Caspart, bud-variation in the moss-
rose, i. 457 : on the ovules and pol-
len of Oytisus, i. 466-467: crossing of
Oytisus purpart us and C. laburnum,
i.468; trifacial orange, i. 470; differ-
ently-coloured flowers in the wild
[";,.',/ Iv&ea, i. 400; sterility of the
horse-radish, ii. 208.

•C.sstelnau, on Brazilian cattle, i.
113.

Castration, assumption of female
characters caused by. ii. 69.

Casvarius bennettii, ii. nil.

Cat, domestic, i. (10-65 ; early domes-
tication and probable origin of the,
i. 59-60 ; intercrossing of with wild
species, i. 60-61; variations of, i. 62-65;
feral, i. 64, ii. 47; anomalous, i. 65;
polydactylism in, ii. 24; black, indi-
cations of stripes in young, ii. 73. 74 ;
tortoiseshell. ii. 95 ; effects of cross-
ing in. ii. 110; fertility of, ii. 139;
difficulty of selection in, ii. 283, 286;
length of intestines in, ii. 364 ; white
with blue ej-es. deafness of, ii. 396;
with tufted ears. ii. 421.

Cataract, hereditary, ii. 18, 102.

Caterpillars, effect of changed food
on. ii. 338.

Catlix, G.. colour of feral horses in
North America, i. 80.

Cattle, European, their probable
origin from three original species, i.
101-105: humped, or^Zebus, i. 101-
11 i-J ; intercrossing of, i. 106, 116-118 ;
wild, of Chillingham, Hamilton,
Chartley, Burton Constable, and
Gisburne, i. 107-108. ii. 148; colour
of feral, i. 107-108, ii. 128; British
breeds of, i. 110-111 ; South African
breeds of, i. 112: South American
breeds of, i. 113. ii. 218; Niata, i.
113-116, ii. 249, 253. 400 ; effects of
food and climate on, i. 116-117; ef-
fects of selection on, i. 117-118; Dutch-
buttoeked. ii. 17 ; hornless, produc-
tion of horns in. ii. 43. 54 : reversion
in, when crossed, ii. 56. 57: wild-
ness of hybrid, ii. til ; short-horned,

prepotency of. ii.85; wild, influence of
crossing and segregation on, ii. 110;
crosses of. ii. 121. 131. 147; of Falk-
land Islands, ii. 128; mutual fertility
of all varieties of. ii. 138; effects of in-
terbreeding on. ii. 146-148 ; effects of
careful selection on. ii. 235, 241 ; na-
ked of Columbia, ii. 248; crossed
with wild banteng in Java. ii. 250;
with reversed hair in Banda Orien-
tal, ii. 2411: selection of trifling char-
acters in. ii. 253; fashion in. ii. 254 ;
similarity of best races of, ii. 291 ;
unconscious selection in. ii. 259; ef-
fects of natural selection on anoma-
lous breeds of, ii. 274 : light-colour-
ed, attacked by Hies. ii. 577. 105 ;
Jersey, rapid improvement of. ii.
283; effects of disuse of parts in. ii.
361 ; rudimentary horns in, ii. 380 ;
supposed influence of humidity on
the hair of, ii. 393 ; white spots of, li-
able to disease, ii. 406: supposed
analogous variation in. ii. 419; dis-
placement of long-horned by short-
horned, ii. 508, 509.

Cauliflower, i. 389 ; free-seeding of,
in India, ii. 374; rudimentary flow-
ers in, ii. 380.

Cavalier pigeon, ii. 123.

infill aperea, ii. 186.

Cat ( Cams azarce), sterility of, in con-
finement, ii. 188.

Cebus azarce, ii. 188.

( . i idomyia, larval development of, ii.
342. 431, 440; and Misolampus, i. 16.

Cedars of Lebanon and Atlas, i. 438.

Celery, turnip-rooted, i. 392; run
wild, ii. 48.

Cell-theory, ii. 443.

i , losia cristata, i. 439.

Celsus, on the selection of seed-corn,
i. 383, ii. 246.

Celts, early cultivation of the cabbage
by the, i. 390 ; selection of cattle and
horses by the, ii. 245. 246.

Cenchrus, seeds of a, used as food, i.
372.

d ntaurea eyamts, bud-variation in, i
456.

Cephalopoda, spermatophores of, ii.
459.

Cerasus padtis, yellow-fruited, ii. 31.

( '< rcoieptes, sterility of, in captivity, ii.
186.

< • rcqpithecus, breeding of a species of,
in captivity, ii. 187.

Cereals, i. 376-378; of the Neolithic
period in Switzerland, i. 381; adap-
tation of, to soils, ii. 367.

Cereus, ii. 52.

( i n us 7" > iosissimvs and phyllanthiu,
reversion in hybrids of. i. 471.

i , i vus canadensis, ii. 193.

< '. rvus //mini. ii. 149.

Cetacea, correlation of dermal sys-
tem and teeth in the, ii. 395.

Ceylon, cats of, i. 63; pigeon-fancy-
ing in, i. 251.

5'26

CHAM.Er.0P9.

INDEX.

COCHLEAEIA.

Chamcerope Jiumilis, crossed with date

palm, i. 479.
Chamisso, on seeding bread-fruit, ii.

2U5.
Channel islands, breeds of cattle in,i.

103.
Chapman, Professor, peach-trees pro-
ducing nectarines, i. 411.

Chapuis, P., sexual peculiarities in
pigeons, i. 200, ii. 95 ; effect produced
by first male upon the subsequent
progeny of the female, i. 486 ; ster-
ility of the union of some pigeons, ii.
198.

Characters, fixity of, ii. 289; latent,
ii. 68-75, 477-478; continued diver-
gence of, ii. 291 ; antagonistic, ii. 479.

Chardin, abundance of pigeons in
Persia, i. 250.

Charlemagne, orders as to the selec-
tion of stallions, ii. 246.

Chartlet, wild cattle of, i. 107.

Chate, reversion of the upper seeds
in the pods of stocks, ii. 417.

Chatin, on Ranunculus ficaria , ii. 208.

Chaundt, Mr., crossed varieties of.
cabbage, ii. 161.

Cheetah, general sterility of, in cap-
tivity, ii. 185.

Cheiranthus cheiri, i. 458.

Cherries, i. 418-419 ; bud-variation in,
i. 451 ; white Tartarian, ii. 278 ; va-
riety of, with curled petals, ii. 2S1 ;
period of vegetation of, changed by
forcing, ii. 374.

Chevreul, on crossing fruit-trees, ii.
160.

Chickens, differences in characters of,
i. 301-302 ; white, liable to gapes, ii.
276, 405.

Chigoe, ii. 332.

Chile, sheep of, i. 120.

Chillingham cattle, identical with
Bos primigenius, i. 104; characters
of, i. 107.

Chiloe, half-castes of, ii. 63.

China, cats of, with drooping ears, i.
64 ; horses of, i. 71 ; striped ponies
of, i. 77; asses of, i. 82; notice of
rabbits in, by Confucius, i. 131 ;
breeds of pigeons reared in, i. 251 ;
breeds of fowls of, in fifteenth cen-
tury, i. 281, 299 ; goose of, i. 287.

Chinchilla, fertility of, in captivity,
ii. 186.

Chinese, selection practised by the,
ii. 248 ; preference of the, for horn-
less rams, ii. 253 ; recognition of the
value of native breeds by the, ii. 377.

Chinese, or Himalayan rabbit, i. 136.

" Chivos," a breed of cattle in Para-
guay, i. 113.

Choux-raves, i. 389.

Christ, H., on the plants of the Swiss
Lake-dwellings, i. 373, 384 ; interme-
diate forms between Pirnis sylveatris
and montann, i. 437.

Chrysanthemum, i. 455.

Chrysotisf estiva, ii. 337.

Cineraria, effects of selection on the,

ii. 243.
Circassia, horses of, ii. 129.
Circumcision, ii. 35.
Cirripedes, metagenesis in, ii. 439.
Cistus, intercrossing and hybrids of, i.

405, 467, ii. 173.
CUtus tricuspis, bud-variation in, i.

453.
Citrons, i. 403.
" Citrus aurantium fructu rariabi'A"

i. 405. •
Citrus decumana. i. 403.
Citrus lemonum, i. 404.
Citrus medica, i. 403, 404.

Cleft palate, inheritance of, ii. 3S.

Clemente, on wild vines in Spain, i.
400.

Clermont-Tonnerre, on the St. Val-
ery apple, i. 481.

Clapham, A., bud-variation in the
hawthorn, i. 453.

" Claquant," i. 172.

" Claquers " (pigeons), i. 193.

Clark, G., on the wild dogs of Juan
de Nova, i. 41 ; on striped Burmese
and Javanese ponies, i. 77 ; breeds
of goats imported into the Mauritius,
i. 128 ; variations in the mammae of*
goats, i. 128 ; bilobed scrotum of
Muscat goat, ibid.

Clark, H. J., on fission and gemma-
tion, ii. 430.

Clarke, R. T., intercrossing of straw-
berries, i. 423.

Clarke, T., hybridisation of stocks, i.
479, ii. 117.

Clarkson, Mr., prize-cultivation of
the gooseberry, i. 428.

Classification, explained by the
theory of natural selection, i. 23.

Climate, effect of, upon breeds of
dogs, i. 53 ; on horses, i. 69-71 ; on
cattle, i. 116, 117; on the fleece of
sheep, i. 124, 125 ; on seeds of wheat,
i. 380 ; on cultivated cabbages, i.
391 ; adaptation of maize to, i. 388.

Climate and pasture, adaptation of
breeds of sheep to, i. 122.

Climate and soil, effects of, upon
strawberries, i. 425.

Cline, Mr., on the skull in horned and
hornless rams, ii. 401.

Clos, on sterility in Ranunculus fica-
ria, ii. 208.

Clotzsch, hybrids of various trees, ii.
101.

Clover, pelorism in, ii. 415.

Co ate, Mr., on interbreeding pigs, ii.
152.

Coccus of apple trees, ii. 280.

Cochin fowls, i. 275, 303, 304, 314-315 ;
occipital foramen of, figured, i. 316 ;
section of skull of, figured, i. 318;
cervical vertebra of, figured, i. 323.

Cochineal, persistence of, ii. 285 ; pre-
ference of, for a particular cactus, ii.
332.

CocMearia armoracia, ii. 208.

INDEX.

CORRELATION.

527

Cock, came, natural selection in, ii.
2T-3 : spur of. grafted on the comb,
ii. 350; spur of. inserted into the eye
of an ox. ii. 412; effect of castration
upon the. ii. 89.

Cock's-co.mb. varieties of the, i. 43!).

Cocoon's, of silkworms, variations in,
i. 866.

Codfish, bulldog, i. 113; number of
eggs in the. ii. 453.

Ca hgeny8paca, ii. 187.

Colin, prepotency of the ass over the
horse, ii. S8; on cross-'breeding, ii.
133; on change of diet. ii. 866.

Collinson. Peter, peach-tree produc-
ing a nectarine, i. 410.

Coloration, in pigeons, an evidence
of unity of descent, i. 238-240.

Colour, correlation of. in dogs. i. 42-
43 : persistence of. in horses, i. OS ;
inheritance and diversity of, in hors-
es, i. 73 : variations of, in the ass, i.
: : of wild or feral cattle, i. 108 ;
transmission of. in rabbits, i. 133 ;
peculiarities of, in Himalayan rab-
bits, i. 130 ; influence of, ii. 275-279 ;
correlation of. in head and limbs, ii.
390; correlated with constitutional
peculiarities, ii. 404-40(5.

Colour and odour, correlation of, ii.
391.

Colour-blindness, hereditary, ii. 19 ;
more common in men than in wo-
men, ii. 93-94 : associated with in-
ability to distinsniish musical sounds,
ii. 395.

Colours, sometimes not blended by
crossing, ii. 110-117.

Ctihnnba affinis, Blyth, a variety of C.
lir i, i. i. 225.

Co'iimbn amalicB, Brehm. a variety of
C. lir 'hi. i. 205.

Cbhanba guinea, i. 224.

Columba gymnoeydus, Gray, a form of
G. liria.'i. 336.

Colvmba gymnophtha'mos, hybrids of,
with V. anas, i. 23(i; with V. ma-
culosa, i. 237.

/ in/, rmedia, Strickland, a va-
riety of ('. /iria. i. 226.

Columba i. u oc pfiala, ii. 190.

Columba )■ uconota, i. 224, 238.

Volumba Mtoralis, i. 221.

t;>'>iu,>,;i a, hi, ii. 43-55: the parent of
domestic breeds of pigeons, i. 224-
225: measurements of, i. 166 : fisur-
ed, i. 168: sknll figured, i. 201; low-
er jaw figured, i. 202, 207; scapula
figured, i. 206.

Columba wctuosa, i. 224.

Columba migratoria and lei/cocepfiata,
diminished fertility of, in captivity.
ii. 190.

Columba num. i. 224: crossed with
common pigeon and C. gymnoph-
thaknoa, i. 396.

Columba palwnbue, i. 236, ii. 420.

Columba run Oris, i. 224. 223, 239.

Columbu Scmmperi, i. 225.

Columba torquatrix, ii. 420.
Calu mhii turricola, i. 225.

Columbia, cattle of, i. 113.

Columbine, double, i. 439, ii. 397.

Columbus, on West Indian doss. i. :; i.

Columella, on Italian shepherd's
dogs, i. 37: on domestic fowls, i.
281. 398, ii. 345, 512; on the keeping
of ducks, i. 335 : on the selection of
seed-com, i. 38.J; on the benefits of
change of soil to plants, ii. 179 ; on
the value of native breeds, ii. 377.

Colza, i. 393.

Comb, in fowls, variations of. i. 30G-
307 ; sometimes rudimentary, ii. 379.

Compensation, law of, i. 381.

Compensation of growth, ii. 411-412.

Complexion, connexion of, with con-
stitution, ii. 403, 404.

Composite, double flowers of, i. 439,
ii. 204, 380.

Conception, earlier in Alderney and
Zetland cows than in other breeds,
i. 111.

Conditions of life, changed effect of,
ii. 500 ; on horses, i. 69 ; upon va-
riation in pigeons, i. 258-259 ; upon
wheat, i. 380; upon trees, i. 435; in
producing bud-variation, i. 490 ; ad-
vantagesof. ii. 178-182, 215; sterility
caused by, ii. 183-301 ; conducive to
variability, ii. 30S-315. 471 ; accumu-
lative action of. ii. 315-317; direct
action of. ii. 327-332.

Condor, breeding in captivity, ii. 188.

Confinement, effect of, upon the
cock, ii. 69.

Confucius, on the breeding of rabbits
in China, i. 131.

Conollt, Mr., on Angora goats, ii.
392.

Constitutional differences in sheep,
i. 121-122; in varieties of apples, i.
420-421 ; in pelargoniums, i. 433 ; in
dahlias, i. 445.

Constitutional peculiarities in
strawberries, i. 425 ; in roses, i. 441.

Consumption, hereditary, ii. 17 ; peri-
od of appearance of, ii. 99 ; correlat-
ed with complexion, ii. 404.

Contabescence, ii. 303-303.

Convolvulus batata*, ii. 206, 372.

Convolvulus tricolor, bud-variation in,
i. 489.

Cooper, Mr., improvement of vege-
tables by selection, ii. 247.

Cooper, White, hereditary peculiari-
ties of vision, ii. 18: association of
affections of the eyes with those of
other systems, ii. 395.

Corals, bud-variation in. i. 449 ; non-
diffusion of cell-iremmules in, ii. 454.

Corbie. See Boitard.

Cornea, opacity of, inherited, ii. 19.

Cornus mascula, yellow-fruiied. ii. 31.

Correlation, ii. 384 ; of neighbour-
ing parts, ii. 38)1 ; of change iu the
whole body and in some of its parts,
ii. 386 ; of homologous parts, ii. 387-

528

CORRELATION.

INDEX.

399; inexplicable, ii. 399-401; com-
mingling of, with the effects of other
agencies, ii. 401-403.
Correlation of skull and limbs in
swine, i. 74 ; of tusks and bristles in
swine, i. 9S ; of multiplicity of horns
and coarseness of wool in sheep, i.
120 ; of beak and feet in pigeons, i.
211-213 ; between nestling down and
colour of plumage in pigeons, i. 237;
of changes in silk-worms, i. 366 ; in
plants, ii. 265 ; in maize, i. 3S8 ; in
pigeons, i. 207-210, 266 ; in fowls, i.
331-332.
Corresponding periods, inheritance

at. ii. 96-103.
Corrientes, dwarf cattle of, i. 113.
Corringham, Mr., influence of selec-
tion on pigs, ii. 240.
Corsica, ponies of, i. 69.
" Cortbeck " (pigeon) of Aldrovandi,

i. 254.
Corrirs corone and ft comix, hybrids

of, ii. 119.
Co i ' ijflalh, flower of. ii. 78.
CorydaMs cava, ii. 104.
Corydalis t-olida, sterile when peloric,

ii. 203.
Corydalis tuberosa, peloric by rever-
sion, ii. 77-78.
Corylus aveMana, i. 429.
Costa, A., on shells transferred from
England to the Mediterranean, ii.
&3S.
" Couve Tronchuda," i. 389.
Cow, inheritance of loss of one horn
in the, ii. 22, 35 ; amount of milk
furnished by the, ii. 362 ; develop-
ment of six mamma? in. ii. 382.
Cowslip, ii. 32, 238.
Cracid^e, sterility of the, in captivity,

ii. 191.
Cranes, fertility of, in captivity, ii.

192.
Cratcegrus cxcyacantha, i. 437, ii. 29, 2S0,

312, '453.
Orakegus monogyna, i. 438.
Gratcegus eibirica, i. 438.
Crawfurd, J., Malasian cats, i. 64;
horses of the Malay Archipelago, i.
66 ; horses of Japan, i. 71 ; occur-
rence of stripes in young wild pigs
of Malacca, i. 99 ; on a Burmese
hairy family with deficient teeth, ii.
98, 394 ; Japanese origin of the ban-
tam, i. 278 ; game fowls of the Phi-
lippine islands, i. 281 ; hybrids of Gal-
lux varins and domestic fowl, i. 284 ;
domestication of GaUiU bankiva, i.
286 ; feral fowls in the Pellew islands,
i. 288 ; history of the fowl, i. 297-298 ;
history of the domestic duck, i. 335 ;
domestication of the goose, i. 347 ;
cultivated plants of New Zealand, i.
376 ; breeding of tame elephants in
Ava, ii. 184 ; sterility of Goura com-
mit a in confinement, ii. 190 ; geese of
the Philippine islands, ii. 197.
Creepers, a breed of fowls, i. 278.

Crested fowl, i. 276 ; figured, i. 279.
" Creve-cosur," a French sub-breed

of fowls, i. 277.
Crisp, Dr., on the brains of the hare

and rabbit, i. 158.
Crocker, C. W., singular form of Be-
gonia frigida, i. 440, ii. 203; steri-
lity in Ranunculus ficaria, ii. 208.
Crocus, ii. 201.

Cross-breeding; permanent effect of,
on the female, i. 485.

Crossing, ii. 108-177, 211-233; a cause
of uniformity, ii. 109-114, 211-212 ; oc-
curs in all organized beings, ii. 114"-
116 ; some characters not blended by,
ii. 116-120, 211 ; modifications and new
races produced by, ii. 120-135 ; causes
which check, ii. 126-137 ; domestica-
tion and cultivation favorable to, ii.
137-141, 229; beneficial effects of, ii.
142-162, 212-214; .necessary in some
plants, ii. 163-173, 214-215, 505 ; sum-
mary of subject of, ii. 173-177; of
dogs with wolves in North America,
i. 34-35; with Ganis cancrivorus in
Guiana, i. 36 ; of dog with wolf, de-
scribed by Pliny and others, i. 37 ;
characters furnished by, brought out
by reversion in the progeny J ii. 48-
51 ; a direct cause of reversion, ii.
55-63, 65 ; a cause of variability, ii.
318-322.

Crustacea, macrourous, differences
in the development of the, ii. 441.

Crustacean with an antenna-like de-
velopment of the eye-peduncle, ii.
468.

Crtptogamic plants, bud-variation in,
i. 460.

Cuba, wild dogs of, i. 41.

" Cuckoo," sub-breeds of fowls, i. 295.

Cucumber, variation in number of car-
pels of, i. 433 ; supposed crossing of
varieties of the, i. 480.

Gueuwds tnomordica, i. 434.

Cucumis saliva, i. 433.

Oucurbita, dwarf, correlation of leaves
in, ii. 398.

Oucurbita maxima, i. 430, 432.

CucurbUa moschata, i. 430, 432.

Cucurbit a pepo, i. 430, ii. 135 ; varieties
of, i. 431 ; relation in size and num-
ber of fruit of, ii. 412.

Cucurbitaceje, i. 430-434; supposed
crossing of, i. 480 ; Nandin's obser-
vations on hybrids of, ii. 210 ; accli-
matisation of, ii. 377.

" Culbutants " (pigeons), i. 184.

Cultivation of plants, origin of,
among savages, l. 373-374; fertility
increased by, ii. 139-141.

Cunier, on hereditary night-blind-
ness, ii. 19.

Currants, of Tierra del Fuego, i. 373 ;
bad-variation in, i. 452.

Curtis, Mr., bud-variation in the rose,
i. 458.

Cuvier, on the gestation of the wolf
- i. 41 ; the odour of the jackal, an ot>-

INDEX.

DE CAND0LLE.

529

stacle to domestication, i. II: differ-
ences of the skull in dogs, i. 49 : ex-
ternal characters of dogs, i. 50 ; elon-
gation of the Intestines in domestic
pigs, i. 95, ii. 365; fertility of the
hook-billed duck, i. 3*1 ; number of
digits, ii. 23; hybrid or ass and ze-
bra, ii. 58 ; breeding of animals in the
Jardin des Plantes, ii. ls.3; sterility
of predaceous birds in captivity, ii.
188-189; facility of hybridisation in
confinement, ii. 190.

Cyanosis, affection of fingers in, ii.
30!).

Cyclamen, bud-variation in, i. 458.
cardunctdus, ii. 48.

Cynips fecundatrix, ii. 34-2.

bains hamadryas, ii. 187.
inns auratus, i. 357-353.
ithus, ii. 172.

Cyrtopod'vnn, ii. KiG.

Cytisus Adami, ii. 437; its trad-varia-
tion, i. 465-467, 487, ii. 52 ; seedlings
from, i. 460 : different views of its ori-
gin, i. 407-403 ; experiments in cross-
ing ('. purpureus and Laburnum to
produce, i. 408 : its production by M.
Adam. it/a/. ; discussion of origin of,
i. 470.

Cytisus a$pino4aburnitm, ovules and
pollen of. i. 407 : origin of, i. 40'.).

Cytisus alpinus, i. 107.

Cytisus laburnum, i. 405, 407, 403, 409,
476,

Cytisus purpureo-elongatus, ovules and
pollen of, i. 407; production of, L
468.

Cytisus purpureus, i. 405, 400, 407, 408,
469, 476.

Daitlbom, effects of food onhymenop-
tera. ii. 338.

Dahlia, i. 441-445. ii. 147 : bud varia-
tion by tubers in the. i. 462 : improve-
ment of. by selection, ii. 20-2: steps
in cultivation of, ii. 315 ; effect of
conditions of life on. ii. 329-331; cor-
relation of form and color in, ii. 393-
399.

Daisy, hen and chicken, i. 439; Swan
River, ii. 315.

Dalbret, varieties of wheat, i. 379.

Dalibert, changes in the odors of
plants, ii. 331.

Dally. Dr.. on consanguineous mar-
riages, ii. 152.

Daltonism, hereditary, ii. 19.

Damaras, cattle of, i. 112, ii. 251.

Damson, i. 418.

Dantjolo, Count, on silkworms, i. 304.

Daniell. fertility of English dogs at
Sierra Leone, ii. 197.

Danish Middens, remains of dogs in,
i. 31.

Dappling in horses, asses, and hy-
brids, i. 73.

Dareste, C, on the skull of the Polish
fowl. i. 317; on the production of
monstrous chickens, ii. 34S ; co-ex-

istence of anomalies, ii. 398-399 ; pro-
duction of double monsters, ii. 408-
409.

Darvii.l, Mr., heredity of good qua-
lities in horses, ii. 21.

Darwin, c. on L pus mageUanicus,
i. 141; on the wild potato, i. 398;
dimorphism in the polyanthus and
primrose, ii. 32.

Darwin, Dr., improvement of vege-
tables by selection, ii. 217.

Darwin. SirF., wildness of crossed
pigs. ii. 01.

D'Asso, monogynous condition of the
hawthorn in Spain, i. 438.

Basyprocta aguh, ii. ISO.

Date-palm, varieties of the. ii. 309 ;
effect of pollen of, upon the fruit of
Ckamcerops, i. 479.

Datura, ii. 52; variability in. ii. 321.

Datura lawis and stramonium, rever-
sion in hybrids of, i. 471.

Datura stramonium, ii. 87.

Daubenton, variations in the number
of mamma; in dogs, i. 50 ; propor-
tions of intestines in wild and domes-
tic cats. i. 65, ii. 3'»4.

Daudin, on white rabbits, ii. 278.

Davy, Dr.. on Bhcep in the West In-
dies, i. 124.

Dawkins and Sandford, early domes-
tication of Bos longifrons in Britain,
i. 104.

Deaf-mutes, non-heredity of, ii. 34.

Deafness, inheritance of. ii. 100.

Deby. wild hybrids of common and
musk ducks, ii. 02.

De Candolle, Alph.. number and ori-
gin of cultivated plants, i. 309-370,
440 ; regions which have furnished no
useful plants, i. 374; wild wheat, i.
377 ; wild rye and oats. H/hl. ; antiqui-
ty of varieties of wheat, i. 381; appa-
rent inefficacy of selection in wheat,
i. 383; origin and cultivation of
maize, i. 3SG^ii. 370; colours of seeds
of maize, i. 387; varieties and origin
of the cabbage, i. 391-392; origin of
the garden pea, i. 393 ; on the vine,
i. 400, ii. 303; cultivated species of
the orange group, i. 403 ; probable
Chinese origin of the peach, i. 407;
on the peach and nectarine, i. 409,
412; varieties of the peach, i. 412;
origin of .the apricot, i. 414; origin
and varieties of the plum. i. 415 : ori-
gin of the cherry, i. 418 ; varieties of
the gooseberry, i. 420 : selection prac-
tised with forest-trees, i. 434; wild
fastigate oak, i.435; dark-leaved va-
rieties of trees, ibid. : conversion of
stamens into pistils in the poppy, i.
439 ; variegated foliage, i. 'MO ; hered-
ity of white hyacinths, i. 440, ii. 32;
changes in oaks dependent on age, i.
405 ; inheritance of anomalous cha-
racters, ii. 30-31 ; variation of plants
in their native countries, ii. 309: de-
ciduous bushes becoming evergreen

.30

DE CANDOLLE.

INDEX.

in hot climates, ii. 367 : antiquity of
races of plants, ii. 512-513.

De Candolle, P., non-variability of
monotypic genera, ii. 321 ; relative
development of root and seed in Ila-
pharvm sutivus,.n. 412.

Decaisne, on the cultivation of the
wild carrot, i. 392 ; varieties of the
pear, i. 422 ; intercrossing of straw-
berries, i. 423 ; fruit of the apple, i.
481; sterility of Lysimacftia nwmrnu-
laria, ii. 207 ; tender variety of the
peach, ii. 371.

Deer, assumption of horns by female,
ii. 69 ; imperfect development of
horns in a. on a voyage, ii. 193.

Deer, fallow, ii. 120.

Deerhound, Scotcn, difference in size
of the sexes of, ii. 95 ; deterioration
of, ii. 150.

Degeneration of high-bred races, un-
der neglect, ii. 289.

De Jong'he, J., on strawberries, i. 424,
ii. 293 ; soft-barked pears, ii. 279 ; on
accumulative variation, ii. 310 ; re-
sistance of blossoms to frost, ii. 368.

Delamer, E. S., on rabbits, i. 135, 140.

Delphinium ajaois) ii. 33.

Delphinium consolida, ii. 31-33.

Dendrocygna viduata, i. 223, ii. 192.

Dentition, variations of, in the horse,
i. 67.

Deodar, i. 438.

Desmahest. distribution of white on
dogs, i. 43; cat from the Cape of
Good Hope, i. 64; cats of Madagas-
car, ibid. ; occurrence of striped
young in Turkish pigs. i. 99; French
breeds of cattle, i. 103; horns of
iroats, i. 123 ; on hornless goats, ii.
380.

Desor, E., on the Anglo-Saxon race in
America, ii. 331.

Desportes, number of varieties of
roses, i. 441.

Devay. Dr., singular case of albinism,
ii. 28 ; on the marriage of cousins, ii.
152; on the effects of close inter-
breeding, ii. 176-177. 317.

Development and metamorphosis, ii.
464-465.

Development, arrests of, ii. 379-3S3.

Development, embryonic, ii. 438-111.

D'HERVET-Saint-Denys, L., on the
ya-mi, or imperial race of the Chi-
nese, ii. 248.

Dhole, fertility of the, in captivity,
ii. 185.

Diabetes, occurrence of, in three <
brothers, ii. 27.

Dianthus, contabescent plants of, ii.
202-203; hybrid varieties of, ii. 321.

Dianthus armeria and deltoides, hy-
brids of, ii. 123.

Dianthus oarbatus, i. 458.

ZKanthw caryophyMw, i. 458.

Dianthus japonicus, contabescence of
female organs in, ii. 2D2.

Dichogamous plants, ii. 115.

Dickson, Mr., on "running" in car-
nations, i. 458 ; on the colours of
tulips, i. 463.

Dicotyles torquatus and laMatus, ii. 1S4.

Dieffenbach, dog of New Zealand,
i. 39 ; feral cats in New Zealand, i.
64; polydactylisin in Polynesia, ii.
24.

Dielytra, ii. 77.

Diet, change of, ii. 304-365.

Digitalis, properties of, affected by
culture, ii. 331 ; poison of, ii. 455.

Digits, supernumerary, ii. 76 ; ana-
logy of, with embryonic conditions,
ii. 22 : fusion of, ii. 410.

Dimorphic plants, ii. 202 ; conditions
of reproduction in, ii. 220-225.

Dimorphism, reciprocal, ii. 115.

Dingo, i. 39 ; variation of, in colour,
i. 41 ; half-bred, attempting to bur-
row, i. 42 ; attraction of foxes by a
female, i. 45 ; variations of, in con-
finement, ii. 318.

Dkeciousnesm of strawberries, i. 425.

Diseases, inheritance of, ii. 10-18 ;
family uniformity of, ii. 76 ; inher-
ited at corresponding periods of life,
ii. 99-101 ; peculiar to localities and
climates, ii. 333 ; obscure correla-
tions in, ii. 399-401 ; affecting cer
tain parts of the body, ii. 455 ; oc
curring in alternate generations, ii
480.

Distemper, fatal to white terriers, ii.
275.

Disuse and use of parts, effects of, ii.
356-305, 423-425. 500; in the skele-
ton of rabbits, i. 155-159 ; in pigeons,
i. 211-218 ; in fowls, i. 327-331 ; in
ducks, i. 343-346 ; in the silk-moth,
i. 361-367.

Divergence, influence of, in produc-
ing breeds of pigeons, i. 26S.

Dixon, E. S., on the musk duck, i.
223 ; on feral ducks, i. 233 ; on feral
pigeons in Norfolk Island, i. ibid:
crossing of pigeons, i. 235 ; origin ot
domestic fowls, i. 279 ; crossing of
QaUus SoriiKra'ii and common fowl,
i. 2S4 ; occurrence of white in the
young chicks of black fowls, i. 396 ;
Paduan fowl of Aldrovandi, i. 299 ;
peculiarities of the eggs of fowls, i.
300; chickens, i. 301-302; late de-
velopment of the tail in Cochin
cocks, 1. 303 ; comb of lark-crested
fowls, i. 309 ; development of webs
in Polish fowls, i. 313 ; on the voice
ot fowls, i. 313 ; origin of the duck,
i. 334 ; ducks kept by the Romans,
i. 335 ; domestication of the goose,
i. 347 ; gander frequently white, i.
348; breeds of turkeys, i. 353; in-
cubatory instinct of mongrels of
non-sitting races of fowls, ii. 60-61 ;
aversion of the dove-cot pigeon to
pair with fancy birds, ii. 130 ; fertil-
ity of the goose, ii. 140 ; general
sterility of the guans in captivity, ii.

[NDEX.

531

191 : fertility of geese in captivity,

ii. 192; white pea-1'owl. ii. 899-400.

Dobell, II.. inheritance of anomalies
of the extremities, ii. 25 ; non-re-
version to a malformation, ii. 61.

Dobrizhoffer. abhorrence of incest
by the Abipones. ii. 153.

Dogs, origin of. i. 27 ; ancient breeds
of, i. 30. ii. 512 : of neolithic, bronze
and iron periods in Europe, i. 31.32,
ii. 511 ; resemblance of two various
species of canida?. i. 34 ; of North
America compared with wolvi s. i.
86 : of the West Indies. South
America, and Mexico, i. 86, 15 : of
(Utiana. i. 86; naked dogs of Para-
guay and Peru. i. 3T. 45 : dumb, on
Juan Fernandez, i. 40 : of Juan de
Kova, i. 41 ; of La Plata. ibid. ; ot
Cuba. ibid. ; of St. Domingo, i. 41 ;
correlation of colour in. i. 12-43:
gestation of. i. 43-44 ; hairless Turk-
ish, i. 44. ii. 274 : inter-crossing of
different breeds of. i. 45-4(1 : charac-
ters of different breeds of, discussed,
i. 49/63 : degeneration of European,
in warm climates, i. 51, 68, ii. 33(i,
303 : liability to certain diseases in
different breeds of. i. 51 and nod ;
causes of differences of breeds dis-
cussed, i. 53-59 : catching fish and
crabs iu New Guinea and Tierra del
Fuego, i. 55 ; webbing of the feet in,
ibid.; influence of selection in pro-
ducing different breeds of. i. 54. 59 :
retention of original habits by. i.
223 : inheritance of polydaetylism in,
ii. 24 : feral, ii. 47 : reversion in
fourth generation of. ii. 49 : of the
Pacific 'Islands, ii. 110. 2(16, 305 ;
mongrel, ii. 117 ; comparative faci-
lity of crossing different breeds of,
ii. 12S ; fertility of. ii. 139. 1S6 ; in-
ter-breeding of. ii. 150 ; selection of,
among the Greeks, ii. 245, 254 ;
among savages, ii. 250-251 ; uncon-
scious selection of, ii. 256-257 : val-
ued by the Fuegians, ii. 2G0 ; clima-
tal changes in hair of, ii. 336 ; pro-
duction of drooping cars in. ii. 362 ;
rejection of bones" of game by, ii.
365 : inheritance of rudiments of
limbs in, ii. 379 : development of
fifth toe in. ii. 3S2 ; hairless, defi-
ciency of teeth in, ii. 393 ; short-
faced, teeth of. ii. 413; probable
analogous variation in, ii. 419 ; ex-
tinction of breeds of. ii. 508.

Dombrain, H. H., on the auricula, ii.
416.

Domestication, essential points iu,
ii. 484-486; favourable to crossing,
ii. 137-138; fertility increased by, ii.
139-141, 213.

Domesticated animals, origin of. ii.
196-197; occasional sterility of, under
changed conditions, ii. 197-199.

Donders, Dr., hereditary hyperme-
tropia, ii. 17.

Dorking fowl, i. 275, 315 ; furcula of,
figured, i. 321.

DoBHOUSB, ii. 187.

Double flowers, ii. 204-205. 208-210;
produced by selection, ii. 212-243.

Doubleday, II.. cultivation of the
filbert pine strawberry, i. 4S6.

Douglas. J., crossing of white and
black game-fowls, ii. 117.

Downing. Mr., wild varieties of the
hickory, i. 374: peaches and necta-
rines from seed. i. 409 : origin of the
Boston nectarine, i. 410; American
varieties of the peach, i. 413 ; North
American apricot, i. 415 : varieties
of the plum. i. 416-417 : oriirin and
varieties of the cherry, i. 418-419 ;
•• twin cluster pippins." i. 420 ; va-
rieties of the apple, i. 421 ; on straw-
berries, i. 422, 425 ; fruit of the wild
gooseberry, i. 42S : effects of graft-
ing upon the seed, ii. 26 ; diseases of
plum and peach trees, ii. 275-276 ;
injury done to stone fruit in America
by the " weevil," ii. 279-380 ; grafts
of the plum and peach, ii. 313 ; wild
varieties of pears, ii. 813 ; varieties
of fruit-trees suitable to different
climates, ii. 369.

Drabu sylvesiris, ii. 199.

Dragon, pigeon, i. 173, 174.

" Draijer " (pigeon), i. 193.

Drinking, effects of, in different cli-
mates, ii. 349.

Dromedart. selection of. ii. 249.

Druce, Mr., inter-breeding of pigs. ii.
151.

Du Chaillu, fruit-trees in West Af-
rica, i. 373.

Duchesne on Fragaria vesca, i. 423,
424. 435.

Dufour, Le'on, on Cecldomyia and
Misocampu8, i. 15.

Duck, musk, retention of perching
habit by the, i. 223 ; feral hybrid of,
i. 233.

Duck, penguin, hybrid of, with Egyp-
tian goose, ii. 88.

Duck, wild, difficulty of rearing, ii.
383 ; effects of domestication on, ii.
335

Ducks, breeds o£,i. 333-334 ; origin of,
i. 334 ; history of, Ibid. ; wild, easily
tamed, i. 335-336 : fertility of breeds
of, when crossed, i. 337 ; with the
plumage of Anas boschas, i. 337;
Malayan penguin, identical in plum-
age with English, i. 338 : characters
of the breeds of, i. 339-343 ; eggs of,
i. 339; effects of use and disuse in,
i. 343-346. ii. 359 ; feral, in Norfolk,
i. 190 ; Aylesbury, inheritance of
early hatching by, ii. 38 ; reversion
in, produced by crossing, ii. 56 ;
wildness of half-bred wild. ii. 61-62 ;
hybrids of, with the musk duck, ii.
62 ; assumption of male plumage by,
ii. 68; crossing of Labrador and
penguin, ii. 123 ; increased fertility

532

INDEX.

EUONTMTJS.

of, by domestication, ii. 140 ; gen-
eral fertility of, in confinement, ii.

192 ; increase of size of, by care in
breeding, ii. 341 : change produced
by domestication in, ii. 317.

Dumeril, Aug., breeding of Sireclon
in the branchiferous stage, ii. 460.

DuN-coloured horses, origin of, i. 78.

Dureau de la Malle, feral pigs in
Louisiana, ii. 47 ; feral fowls in Af-
rica, ibid. ; bud-variation in the pear,
i. 452 ; production of mules among
the Romans, ii. 137.

Dnsicyon .iij/rts/rix, i. 36.

Dutch rabbit, i. 134.

Dutch roller pigeon, i. 186.

Dutrochet, pelorism in the laburnum,
ii. 415.

Duval, growth of pears in woods in
France, ii. 314.

Duval-Jouve, on Leersia oryzoides,
ii. 115-116.

Duvernot. self-impotence in Lilium
candidum, ii. 169.

Dzierzon, variability in the charac-
ters and habits of bees, i. 359.

Earle, Dr., on colour-blindness, ii.
93-94, 395.

Ears, of fancy rabbits, i. 133 ; deficien-
cy of, in breeds of rabbits, i. 135 ;
rudimentary, in Chinese sheep, ii.
379 : drooping, ii. 362, 363 ; fusion of,
ii. 409.

Eaton, J. M., on fancy pigeons, i. 183,
189 ; variability of characters in
breeds of pigeons, i. 199 ; reversion
of crossed pigeons to coloration of
Colurriba lima, i. 242 ; on pigeon fan-
cying, i. 251, 262-263 ; on tumbler-
pigeons, i. 255, ii. 293 ; carrier pi-
geon, i. 211 ; effects of interbreeding
on pigeons, ii. 156-157 ; properties of
pigeons, ii. 239-240 ; death of short-
faced tumblers in the egg, ii. 274 ;
Archangel pigeon, ii. 290,

Echinodermata, metagenesis in, ii.
439-440.

Ectopias, specific difference in num-
ber of tail-feathers in, i. 196.

Ectopistes migratorius, sterile hybrids
of, with Ttrrtur vulgaris, i. 237.

Edentata, correlation of dermal sys-
tem and teeth in the, ii. 394-395.

Edgeworth, Mr., use of grass-seeds
as food in the Punjab, i. 372.

Edmonston, Dr., on the stomach inia-
rus argent a ti/s and the raven, ii. 364.

Edwards and Colin, on English
wheat in France, ii. 370.

Edwards, W. F., absorption of the
minority in crossed races, ii. 111.

Edwards, W. W., occurrence of
stripes in a nearly thoroughbred
horse, i. 76 ; in foals of racehorses,
i. 78.

Eggs, of fowls, characters of, i. 300 ;

variations of, in ducks, i. 339; of the
silk-moth. i. 303.

Egypt, ancient dogs of, i. 30 ; ancient
domestication of the pigeon in, i.
249 ; absence of the fowl in ancient,
i. 297.

Egyptian goose, hybrids of, with pen-
guin duck, i. 341.

Ehrenberg, Prof., multiple origin of
the dog, i. 28; dogs of Lower Egypt,
i. 38; mummies of Eelis manicutata,
i. 60.

Element, male, compared to a prema-
ture larva, ii. 459.

Elements of the body, functional in-
dependence of the, ii. 441-444.

Elephant, its sterility in captivity, ii.
184.

Elk, Irish, correlations in the, ii. 401-
402.

Elliot, Sir Walter, on striped horses,
i. 77; Indian domestic and wild
swine, i. S7 : pigeons from Cairo and
Constantinople, i. 164; fantail pi-
geons, i. 181 ; Lotan tumbler pi-
geons, i. 186 ; a pigeon uttering the
sound Yahu, i. 192; Gallus ban/dva
in Pegu, i. 2S6.

Ellis, "Mr., varieties of cultivated
plants in Tahiti, ii. 309.

Elm. nearly evergreen Cornish variety
of the, i. 436, iC310 ; foliage varieties
of the, i. 436.

Elm, weeping, i. 435 ; not reproduced
by seed, ii. 30.

Emberiza passerina, ii. 193.

Embryos, similarity of, i. 21; fusion
of, ii. 407-408.

Engel, on Lauras sassafras, ii. 331. .

England, domestication of Bos longi-
j'runs in, i. 104 ; selection of horses in,
in media3val times, ii. 2-10 ; laws
against the early slaughter of rams
in, ii. 247.

Ephemerid.£, development of the, ii.
438.

Epidendrum cinnabarinum and E.
zebra, ii. 167.

Epilepsy, hereditary, ii. 17, 100.

Erdt, disease of the white parts of
cattle, ii. 405-406.

Ericaceae, frequency of contabescence
in the, ii. 202.

Erichthonius, an improver of horses
by selection, ii. 245.

Erman, on the fat-tailed Kirghisian
sheep, i. 123, ii. 337 ; on the dogs of
the Ostyaks, ii. 250.

Erodium, ii. 78.

Erythrina Crista-gaSi and E. herbacea,
hybrids of, ii. 320.

Esquilant, Mr., on the naked young
of dun-coloured pigeons, i. 210.

Esquimaux dogs, their resemblance
to wolves, i. 34 ; selection of, ii. 250.

Eudes-Deslongchamps, on appenda-
ges under the jaw of pigs, i. 97-98.

Euonymus Japonicus, i. 461.

EUROrEAN.

INDEX.

533

European cultivated plants, still wild
in Europe, i. 3T0.

Evans, Mr., on the Lotan tumbler pi-
geon, i. 186.

Evelyn, pansiea grown in his garden,
i. I!-.'.

Everest, R., on the Newfoundland
dog in India, i. 51. ii. 308; degenera-
tion of setters in India, i. 53-54;
Indian wild boars, i. 87.

Ewes, hornless, ii. 421.

Extinction of domestic races, i. 269.

Eves, hereditary peculiarities of the,
ii. 17-19; loss of, causing microph-
thalmia in children, ii. 30 ; modifica-
tion of the structure of, by natural
selection, ii. 209-270; fusion of, ii.
409.

Eyebrows, hereditary elongation of
hairs in. ii. 17.

Eyelids, inherited peculiarities of the,
ii. 17.

Eyton, Mr., on gestation in the dog,
i. 44 : variability in number of verte-
bra in the pig, i. 90 ; individual ste-
rility, ii. 198.

Faba vulgaris, i. 397.

Fajbre, observations on jJUgUops trili-
coiden, i. 377.

Fagm sylvatica, ii. 31.

Fair weather, Mr., production of
double flowers from old seed, ii. 204.

Falco aUAdus, resumption of young
plumage by, in captivity, ii. 193.

Falco osxifrac/iis, ii. 278.

Falco giibouteo, copulating in captivity,
ii. 188.

Falco tinnuncidus, breeding in captiv-

' ity. ii. 18S.

Falconer, Dr., sterility of English
bulldogs in India, i. 53; resemblance
between Sivatfieriwn and Niata cat-
tle, i. 113-114; selection of the silk-
worm in India, i. 303 : Castigate apple-
trees in Calcutta, i. 435 ; reproduction
of a supernumerary thumb after
amputation, ii. 24-25; fertility of the
dhole in captivity, ii. 1S5 ; fertility
of English dogs in India, ii. 197 ;
sterility of the tiger in captivity, ii.
185 ; turkeys at Delhi, ii. 197 ; on In-
dian cultivated plants, ii. 201 ; Thi-
bet mastiff and goat, ii. 330.

Falcons, sterility of, in captivity, ii.
188.

Falkland Islands, horses of the, i.
70-71, 80; feral pigs of the. i. 99:
feral cattle of the, i. 100, 110 ; feral
rabbits of the, i. 141.

Fallow deer, ii. 130, 149-150.

Fantail pigeons, i. Isl-is3. ii. 274;
figured, i. 1S2 : furcula of. figured, i.
200: history of, i. 253,254; absence
of oil-gland in, ii. 412.

Faroe Islands, pigeons of the. i. 935.

Fashion, influence of, in breeding, ii.
200.

Fastigate trees, ii. 334, 413.

Faunas, geographical differences, of,

i. sa.

"Favourite" bull. ii. 85, 147.

Feathers, homologous variation in,
ii. 891.

Feet, of pigeons, individual differenc-
es of, i. 197 _; correlations of external
characters in, i. 210.

Feet and beak, correlation of, in pi-
geons, i. 211-215.

FELrD.E, fertility of, in captivity, ii.
185.

F, !hhuhfi*t(*, i. 60.

F.'h caff ra, i. 61.

Ft lis caligiuata, i. 60.

FeHs chaw, i. 00-01.

Felis jiibata, ii. 185.

F, lis lybica, i. 61.

Felis maniculata, i. 60.

Felis mi i n id, i. 62.

Filis ornata, i. 61.

Felis sylvestrie, i. 60.

Felis torguata, i. 61.

Female, affected by male element, ii.
437-438, 463-464.

Female flowers, in male panicle of
maize, i. 387.

Fennel, Italian variety of, i. 392.

Feral cats, i. 64; cattle, i. 110; rab-
bits, i. 140-144 ; Guinea fowl, i. 355 ;
animals and plants, reversion in, ii.
46-48. 63.

Ferguson, Mr., supposed plurality of
origin of domestic fowls, i. 280: chick-
ens of black game-fowls, i. 296 ; rela-
tive size of eggs of fowls, i. 300;
yolk of eggs of game-fowls, i. 301 ;
early pugnacity "of game-cocks, i.
303; voice of the Malay fowl, i. 313;
effects of interbreeding on fowls, ii.
154; selection in Cochin China
fowls, ii. 238 ; on fashion in poultry,
ii. 290.

Fernandez, on Mexican dogs, i. 36.

Ferns, reproduction of abnormal
forms of, by spores, i. 460 ; non-dif-
fusion of cell-gemmules in, ii. 454.

Ferrets, ii. 139, ISO. 250.

Fertilisation, artificial, of the St.
Yalery apple, i. 421.

Fertility, various degrees of, in
sheep, i. 123; unlimited mutual, of
breeds of pigeons, i. 235-237 ; com-
parative of mongrels and hybrids,
ii. 127, 217-220; influence of nourish-
ment on, ii. 140 ; diminished by close
interbreeding, ii. 147, 213-214; re-
duced, of Chillingham wild cattle, ii.
148 ; of domesticated varieties when
crossed, ii. 229-2:30.

Festuca, species of, propagated by
bulblets, ii. 207.

Filberts, spared by tomtits, ii. 279.

FiLirn, on the breeding of branchi-
ferous tritons. ii. 460.

Finches, general sterility of, in cap-
tivity, ii. 189.

Einmkin (pigeon), i. 193.

Finnochio, i. 392.

534

INDEX.

Pie, Scotch, acclimatisation of, ii. 3T3.

Fish, Mr., advantage of change of soil
to plants, ii. 180-181.

Fishes, regeneration of portions of
fins of, ii. 26; variability of, when
kept in tanks, ii. 312 ; marine, living
in fresh water, ii. 306 ; double mon-
sters of, ii. 403.

Fission and gemmation, ii. 429-430.

Fitch, Mr., persistency of a variety of
the pea, i. 397.

Fittest, survival of the, i. 17.

Fitzinger, origin of sheep, i. 119;
African maned sheep, i. 121.

Fixedness of character, conditions of,
discussed, ii. 81-84.

Flax, found in the Swiss lake-dwel-
lings, i. 3S2; climatal difference in
products of, ii. 331.

Fleece, fineness of, in Austrian me-
rinos, ii. 239.

Fleischmann, on German sheep
crossed with merinos, ii. 112.

"Florentiner-Taube," i. 176-177.

Flounder, ii. 70.

Plourens, crossing of wolf and dog,
i. 40; prepotency of the jackal over
the dog, ii. 8S; hybrids of the horse
and ass, ii. 88 ; breeding of monkeys
in Europe, ii. 188.

Flower-garden, earliest known, in
Europe, ii. 262.

Flowers, capricious transmission of
colour-varieties in, ii. 31-32 ; tenden-
cy to uniformity in striped, ii. 90;
scorching of, dependent on colour,
ii. 277 ; change in, caused by condi-
tions of life, ii. 329-330 ; rudimenta-
ry, ii. 381 ; relative position of, to the
axis, ii. 414.

Fcetation, abdominal, ii. 355.

Foley, Mr., wild varieties of pears,
ii. 314.

Foliage, inherited peculiarities of, i.
435; variegation of, i. 440; bud- va-
riation in,i. 459-461.

Food, influence of, on the pig, i. 94 ;
on cattle, i. 116 ; excess of, a cause
of variability, ii. 310-311.

Forbes, D., on Chilian sheep, i. 120;
on the horses of Spain, Chili, and the
Pampas, i. 69.

Formica rafa, ii. 304.

Fortune, R. , sterility of the sweet po-
tato in China, ii. 206; development
of axillary bulbs in the yam, ibid.

Fowl, common, breeds of, i. 273-278 ;
supposed plurality of origin, i. 279 ;
early history of, i. 281-283; causes
of production of breeds of, 1. 282 ;
origin of from Gallus bankira, i. 287-
290, 296-297; feral, notices of, i. 288 ;
reversion and analogous variation in,
i. 290-297, ii. 35, SS', 39, 40, 349, 350 ;
"cuckoo" sub-breeds of, i. 296; his-
tory of, i. 297-299 ; structural charac-
ters of, i. 299-303 ; sexual peculiari-
ties of, i. 304-311, ii. 95 ; external dif-
ferences of. i. 311-314 ; differences of

breeds of, from G. bankira, i. 314
osteological characters of, i. 314-326 ;
effects of disuse of parts in, i. 270-
274, ii. 359; feral, i. 233, ii. 47; poly-
dactylism in, ii. 24 ; fertility of, in-
creased by domestication, ii. 140. 204 ;
sterility of, under certain conditions,
ii. 198 ; influence of selection on, ii.
238, 240,254,255; evils of close inter-
breeding of, ii. 154-156 ; crossing of,
ii. 120-123; prepotency of transmis-
sion in, ii. 87 ; rudimentary organs in,
ii. 379; crossing of non-sitting vari-
eties of, ii. 59-60 ; homology of wing
and leg feathers in, ii. 389 ; hybrids
of, with pheasants and Gallus Sonne-
ratii, ii. 61; black-skinned, ii. 254;
black, preyed upon by the osprey in
Iceland, ii. 278; five-toed, men-
tioned by Columella ii. 512; rump-
less, tailed chickens produced by,
ii. 44-45; Dorking, crosses of, ii.

-„ 117; form of comb and colour of
plumage in, ii. 287 ; game, crossing
of white and black, ii. 117 ; five-
spurred, ii. 468 ; Spanish, liable to
suffer from frost, ii. 368 ; Polish, pe-
culiarities of skull of, ii. 400-401.

Fox, sterility of, in captivity, i. 185.

Fox, S. Bevan, races of bees, i. 359.

Fox, W. Darwin, gestation of the dog,
i. 44; " Negro" cat, i. 63 ; reversion
of sheep in colour, ii. 43-44 ; period
of gestation in the pig, i. 95 ; young
of the Himalayan rabbit, i. 137 ; cross-
ing of wild and domestic turkeys, i.
353 ; reversion in crossed musk
ducks, ii. 56 ; spontaneous segrega-
tion of varieties of geese, ii. 130;
effects' of close interbreeding upon '
bloodhounds, ii. 150; deafness of
white cats with blue eyes, ii. 396.

Foxhounds, i. 56, ii. 150.

Fragaria chiloensis, i. 423.

Fragaria collina, i. 423.

Fragaria dioica of Duchesne, i. 425.

Fragaria elaiior, i. 423.

Fragaria grandifora, i. 423.

Fragaria vesca, i. 423.

Fragaria rirginiana, i. 423.

Fra.ri rms excelsior, i. 434, 459, ii. 30.

Fraxiiu/s lenlhcifolia, ii. 30.

Friesland cattle, probably descended
from Bos primigenhts, i. 104.

Frillback (pigeon), i. 192 ; Indian, i.
190.

Fi ingiUa (Arts, ii. 189.

Fringilla spinas, ii. 189.

Frizzled fowls, i. 278 ; horses, i. 71.

Frog, polydactylism in the, ii. 24.

Fruit, seedless, ii. 205.

Fruit-trees, varieties of occurring
wild, i. 374.

Fry, Mr., on fertile hybrid cats, i. 61 ;
on feral fowls in Ascension, i. 2S8.

Fuchsias, origin of, i. 438 ; bud-varia-
tion in, i. 459.

Fuchsia coecineaxa&fulgens, twin seed
produced by crossing, i. 469.

FUF.GIANS.

INDEX.

D60

PtnsGiANS, their superstition about
killing young water-fowl, i. 874; se-
lection of dogs by the, ii. 960; their
comparative estimation of dogs and

okl women, ii. 263 : their power of

distant vision, ii. 369.
Fungi, parasitic, ii. 843.
FrucuLA. characters and variations of

the. in pigeons, i. 306; alteration of,

by disuse, in pigeons, i. 215-210;

characters of, in fowls, i. 834.
Fusion of homologous parts, ii. 4T0.

Rait, inheritance of peculiarities of,
ii. 15.

Galapagos Archipelago, its peculiar
fauna and flora, i. 21.

'uU "hi. pelorism in, ii. 78.
414.

Galls, ii. 310-313.

Gall-gnats, ii. 342.

Gall-like excrescences not inherited,
ii. 35.

Gallinaceous birds, restricted range
of large, i. 387: general fertility of
in captivity, ii. 190.

GaUinula cMoropus, ii. 192.

GattiniUa nedotts, i. 340.

Galton, Mr., fondness of savages for
taming; animals, i. 33, ii. 196; cattle
of Benguela, i. 112; on hereditary
talent, ii. 16.

Gallbsio, species of oranges, i. 403,
404, 405; hybridisation of oranges,
i. 405 ; persistency of races in the
peach, i. 409; supposed specific dis-
stinctions of peach and nectarine, i.
409; Bizzaria orange, i. 470: cross-
ing of red and -white carnations, i.
4 72 : crossing of the orange and le-
mon, i. 479. ii. 457; effect of foreign
pollen on maize, i. 430 ; spontaneous
crossing of oranges, ii. 115 : mon-
strosities a cause of sterility in
plants, ii. 203; seeding of ordinarily
seedless fruits, ii. 305; sterility of
the sugar cane, ii. 206 ; tendency of
male flowers to become double, ii.
31 is ; effects of selection in enlarging
fruit, Ac, ii. 262-363 ; variation of the
orange tree in North Italy, ii. 309 ;
naturalisation of the orange in Italy,
ii. 371.

QaUus cenws. a hybrid of G.vaiius ani
the domestic fowl, i. 384.

GoBiu bankiva, probable original of
domestic fowls, i. 283, 287-289, 396-
297; game fowl, nearest to. i. 275 ;
crossed with Q. Sbnneratii, i. 384; its
character and habits, i. 385-386, ii.
109; differences of various breeds of
fowls from, i. 314 ; occipital foramen
of, figured, i. 316; skull of, figured,
i. 310; cervical vertebra of. figured,
i. 323 ; furcula of, figured, i. 82 1 : re-
version to, in crossed fowls, ii. 54-
56; hybrid of, with B. varius, i. 285,
ii. 54; number of eggs of, ii. 140.

OaUusjerrugineue, i. 275.

ff alius furcatus, i. 384.
i. 385.

QaUua Sonnerotti, characters and ha-
bits of, i. 388 ; hybrids of. i. 281 ; ii.
61.

OcUlvs Sttmleyi, hybrids of. i. 384.

''"""■ . probably a hybrid,

i. 284.

varius, character and habits of,
i. 384; hybrids and probable hybrids
of, i. 384-285.

Gammer, Lord, his early cultivation
of the pansy, i. 442.

Game-fowl. i. 275, 303, 304, 305.

Gapes, ii. 270.

Garcilazo de la Vega, annual hunts
of the Peruvian Ineas. ii. 351.

Gaknbtt, Mr., migratory propensities
of hybrid ducks, ii. 62.

Garrod, Dr., on hereditary gout, ii.
16.

Gasfarini, a genus of pumpkins,
founded on stigmatic characters, i.
432.

Gaudichautj, bud-variation in the
pear, i. 452 ; apple tree with two
kinds of fruit on branch, i. 471.

Gaudrt, anomalous structure in the
feet of horsps, i. 07.

Gat, on Fmgana grandifiora, i. 423;
on Viola lutea and tricolor, i. 443; on
the nectary of Viola grandiflora, i.
444.

Gatal, domestication of the, i. 105.

Gatot, see Moll.

Gartner, on the sterility of hybrids,
i. 235, ii. 101 ; acquired sterility of
varieties of plants when crossed, i.
431 ; sterility in transplanted plants,
and in the lilac in Germany, ii. 200;
mutual sterility of blue and red flow-
ers of the pimpernel*, ii. 231 ; sup-
posed rules of transmission in cross-
ing plants, ii. 89; on crossing plants,
ii. 123, 158, 161, 163; on repeated
crossing, ii. 322 ; absorption of one
species by another, when crossed, ii.
112; crossing of varieties of the pea,
i. 477 ; crossing maize, ii. 132; cross-
ing of species of Verbascwn, ii. 118,
132; reversion in hybrids, ii. 50,06,
67; of CereuS} i. 471 ; of Tropaolum
«»!/'« and minim, i. 470; variability
of hybrids, ii. 319 ; variable hybrids
from one variable parent, ii. 325 ;
graft hybrid produced by inoscula-
tion-in the vine, i. 474; effect pro-
duced by grafts on the stock, i. 173,
ii. 334; tendency of hybrid plants to
produce double flowers, ii. 308: pro-
duction of perfect fruit by sterile hy-
brids, ii. 209; sexual elective affinity
to. ii. 219 ; self-impotence in /.•
Verbascum, Lilium, and Passiflora,
ii. 169-170; on the action of pollen,
ii. 186; fertilisation of Malva, i. 433,
ii. 430; prepotency of pollen, ii. 227 ;
prepotency of transmission in spe-
cies of Xiaitiiiiiii, ii. 87; bud-varia-

536

INDEX.

tion in Pelargonium znnede, i. 454; in
QBnothera biennis, i. 459; in Achil-
lem millefolium, i. 490; effect of ma-
nure on the fertility of plants, ii. 199 ;
on contabescence, ii. 202 ; inheritance
of plasticity, ii. 291; villosity of
plants, ii. 335.

Geese (anseres), general fertility of, in
captivity, ii. 192.

Gegenbaur, on the number of digits,
ii. 23.

Gemmation and fission, ii. 429-430.

Ge'mmules, or cell-gemmules, ii. 448,
452-455, 459.

Genet, fertility of the, in captivity, ii.
ISO.

Generation, alternate, ii. 433, 410,
466.

Generation, sexual, ii. 431-137.

Genius, inheritance of, ii. 16.

Gentiana amareUa, ii. 205.

Geoffroy Saint-Hilaire, production
of monstrous chickens, ii. 348 ;
'.' Loi de Vaffinite de soi pour soi,'
ii. 407 ; compensation of growth, ii.
411.

Geoffroy Saint-Hilaire, Isid., origin
of the dog, i. 28; barking of a jack-
al, i. 41 : period of gestation and
odour of the jackal, i. 44, 45 ; ano-
malies in the teeth of dogs, i. 49 ;
variations in the proportions of dogs,
i. 50 ; webbed feet of Newfoundland
dogs, i. 55 ; crossing of domestic and
wild cats, i. (il ; domestication of the
ami, i. 105 ; supposed introduction
of cattle into Europe from the East,
ibid. ; absence of interdigital pits in
sheep, i. 121 ; origin of the goat, i.
127 ; feral geese, i. 233 ; ancient his-
tory of the fowl, i. 297-298 ; skull of
the Polish fowl, i. 31(3 ; preference of
the Romans for the liver of white
geese, i. 349 ; polydactylism, ii. 22 ;
assumption of male characters by
female birds, ii. 08-09 ; supernumer-
ary mamma; in women, ii. 70 ; de-
velopment of a proboscis in the pig,
ibid. ; transmission and blending of
characters in hybrids, ii. 119 ; re-
fusal of animals to breed in cap-
tivity, ii. 183 ; on the Guinea pig, ii.
186 ; silkworms producing white co-
coons, ii. 241 ; on the carp, ii. 285 ;
on Heli v lactea, ii. 338 ; on monstro-
sities, ii. 306 ; injury to the embryo a
cause of monstrosity, ii. 324 ; altera-
tion in the coat of horses in coal
mines, ii. 336 ; length of the intes-
tines in wild and "tame animals, ii.
364-305 ; inheritance of rudimentary
limbs in the dog, ii. 379 ; correlation
in monstrosities, ii. 385 ; supernum-
erary digits in man, ii. 388 ; co-exist-
ence of anomalies, ii. 399 ; fusion of
homologous parts, ii. 409-410 ; pres-
ence of hairs and teeth in ovarian
tumors, ii. 443 ; development of teeth
on the palate in the horse, ii. 468.

Geographical differences of faunas,
i. 21-22.

Geological succession of organisms,
i. 22-23.

0( nullum, ii. 78.

Geranium plmum and pyrenaicum, ii.
312.

Geranium pratense, i. 455.

Gerard, asserted climatal change in
Burgundian bees, i. 359.

Gerarde, on varieties of the hya-
cinth, i. 446.

Gerstacker, on hive-bees, i. 361.

Gervais, Prof., origin of the dog. i.
28 ; resemblance of dogs and jack-
als, i. 38 ; taming of the jackal, i.
40 ; number of teeth in dogs, i. 49 ; •
breeds of dogs, i. 51 ; cm tertiary
horses, i. 69 ; biblical notices of
horses, i. 72 ; species of Oris, i. 119 ;
wild and domestic rabbits, i. 130 ;
rabbits from Mount Sinai and Al-
geria, i. 132 ; earless rabbits, i. 135 ;
batrachia with doubled limbs, ii.
467.

Gestation, period of, in the dog,
wolf, &c, i. 43-44 • in the pig, i. 95 ;
in cattle, i. Ill, ii. 387 ; in sheep, i.
123.

Gestures, inheritance of peculiari-
ties in, ii. 15.

" Gooondooks " a sub-breed of fowls,
i. 277.

Ghor-Khur, ii. 58.

Giles, Mr., effect of cross-breeding in
the pig, i. 485.

Giraffe, co-ordination of structure
of, ii. 267.

Girard, period of appearance of per-
manent teeth in dogs, i. 50.

Girou de Buzareingues, inheritance
in the horse, ii. 20 ; reversion by
age in cattle, ii. 54 ; prepotency of
transmission of character in sheep
and cattle, ii. 86 ; on crossing gourds,
ii. 135.

Gisburne, wild cattle at, i. 108.

Gladiolus, i. 438 ; self-impotence of
hybrids of, ii. 171.

Gladiolus colcillii, bud-variation in, i.
459.

Glands, compensatory development
of, ii. 361.

Glastonbury thorn, i. 438.

Glenny, Mr., on the Cineraria, ii.
243.

Gloede, F., on strawberries, i. 428.

Glooer, on the wings of ducks, ii.
359.

"Glouglou" (pigeon), i. 191.

Gloxinia, peloric, i. 439, ii. 203.

Gmelin, on red cats, at Tobolsk, i.
64.

Goat, i. 127-129, ii. 47 ; polydactylism
in the, ii. 24 ; sexual differences in
horns' of, ii. 94 ; valued by South
Africans, ii. 251 ; Thibet, ii. 336 ;
amount of milk and development of
udders iu the, ii. 362 ; hornless, ru-

INDEX.

537

dimentary bony cores in, ii. 380 ;
Angora, ii. 392.

Qodron, odour of the hadrleaa Turk-
ish dog. i. 44 : differences in the
tkull of docs, i. 49 : Increase of
breeds of horses, i. 68 : crossing of
domestic and wild swine, i. 8? : on
coats, i. liS : colour of the skin in
fowls, i. 31-2 ; bees of north Bad
south of France, i. 369 : introduction
of the silkworm into Europe, i. 369 :
variability in the silkworm, i. 368 :
supposed species of wheat, i. 376-
878: on /EgHops tri&coides, i. 377;
variable presence of barbs in grass-
es, i. 378 : colours of the seeds of
maize, i. 887 : unity of character in
cabbages, i. 389-300 : correlation of
colour and odour, ii. 301 : effect of
heat and moisture on the cabbage, i.
891 : on the cultivated species of
Brassi'-n, i. 392 : on the Rouncival
and sugar peas. i. 393-394 : variation
in the number of peas in the same
pod, i. 390 : wild vines in Spain, i.
400: on raising peaches from seed.
i. 409 ; supposed specific distinctness
ofpeach-and nectarine. -i. 409 : nec-
tarine producing peaches, i. 411 ; on
the flower of OorydaUs, ii. 413; ori-
gin and variations of the plum. i.
415 ; origin of the cherry, i. 418 ;
reversion of single-leaved strawber-
ries, i. 424 : five-leaved variety of
Fragaria coll in a. i. 425 : supposed
immutability of specific characters.
i. 432: varieties of Robinia, i. 4:55 :
permanency of the simple-leaved
ash, i. 436 : non-inheritance of cer-
tain mutilations, ii. 35-30 : wild tur-
nips, carrots. a\id celery, ii. 48 : pre-
potency of a goat-like ram. iL "85-86 :
benefit of change of soil to plants.
ii. 179 : fertility'of peloric flowers of
Oorydalxa soHda, ii. 203: seeding of
ordinarily seedless fruit, ii. 906 :
sexual sterility of plants propagated
by buds. &c, ii. 207 : increase of su-
gar in beet-root. ii. 243 : effects of
selection in enlarging particular parts
of plants, ii. 263-963 : growth of the
cabbage in the tropics, ii. 334 : re-
jection of bitter almonds by mice,
ii. 281 : influence of marshy pasture
on the fleece of sheep, ii. 330 : on
the ears of ancient Egyptian pics. ii.
363: primitive distinctness of spe-
cies, ii. 490 : solid hoofed swine, ii.
512.

Goethe, on compensation of growth,
ii. 411.

Goldfish, i. 357-358, ii. 285.

Gomara, on South American cats, i.
03.

Goxgora, number of seeds in the, ii.
453.

Goose, ancient domestication of, i.
347 : sacred to Juno in Home. ibid. ;
inflexibility of organisation of, i.

347 : skull perforated in tufted, i.
348 : characters of breeds and sub-
breeds of. i. 348-849 : variety of. from
Sevastopol, i. 348, ii. 468; feral in
La Plata, i. 233: Egyptian, hybrid
of. with penguin duck. ii. 88 : spon-
taneous segregation of varieties of,
ii. 131 : fertility of. increased by do-
mestication, ii. 140: decreased fer-
tility of. in Bogota, ii. 197 : sterility
of. in the Philippine Islands, ii. 197 ;
st lection of, ii. 247 : white, prefer-
ence of the Romans for the liver of,
ii. 254: persistency of character in.
ii. 300 : Egyptian, change in breed-
ing season of. ii. 300.

Gooseberry, i. 496-498 : bud-varia-
tion in the, i. 151 ; Whitesmith's, ii.
281.

Goppekt, on monstrous poppies, ii.
203.

Gosse, P. H.. feral dogs in Jamaica, i.
41 : feral pigs of Jamaica, i. 100 ;
feral rabits of Jamaica, i. 140 : on
Cohtmba leucoc&fiala^ i. 224: feral
Guinea fowl in Jamaica, i. 233 : re-
production of individual peculiari-
ties by gemmation in a coral, i. 1 19 :
frequency of striped legs in mules,
ii. 57.

Gould. Dr.. on hereditary haemor-
rhage, ii. 10.

Gould, John, origin of the turkev, l.
369.

earonata and Victoria, hybrids
of. i. 237, ii. 190.

Gourds, i. 4:50 : crossins of varieties
of. ii. 130 : ancient Peruvian variety
of, ii. 573.

Gout, inheritance of, ii. 16 : period o'
appearance of. ii. 99.

Geaba, on the pigeon of the Faroe
islands, i. 225.

Grafting, ii. 180 : effects of. ii. 312,
335 : upon the stock, i. 473-474 : upon
the variability of trees, ii. 313 :
changes analogous to bud-variation
produced by. i. 465-467.

Graft-htbrids, i. 408-470, 473-476 ; ii.
437.

Grapes, bud-variation in, i. 451 : cross
of white and purple, i. 472 : green,
liable to disease, ii. 404 : effect of
foreign pollen on, i. 4S0.

Grasses, seeds of. used as food by
savages, i. 371-372.

Gray. Asa, superior wild varieties of
fruit-trees, i. 374 : cultivated native
plants of North America, i. 376. 430 ;
non-variation of weeds, i. 382 : sup-
posed spontaneous crossing of pump-
kins, i. 479 : pre-ordination of varia-
tion, ii. 510 : progeny of husked
form of maize, i. 3S6 ; wild inter-
mediate forms of strawberries, i. 424.

Grat, G. R., on t'olumba gymnocy-
chlSy i. 226.

Gray, J. E.. on Sua pUciceps, i. 92:
on a variety of the gold-fish, i. 358 ;

538

INDEX.

HAWTHORN'.

hybrids of the ass and zebra, ii. 58 ;
on the breeding of animals at Knows-
ley, ii. 183 ; on the breeding of birds
in captivity, ii. 192.

Greene, J. Reay, on the development
of the echinodermata, ii. 440.

Greenhow, Mr., on a Canadian web-
footed dog, i. 55.

Greening, Mr., experiments on Ab-
raxas grossulariata, ii. 338.

GREGSon, Mr., experiments on Abrax-
as grossulariata, ii. 338.

•Grey, Sir George, preservation of
seed-bearing plants by the Austral-
ian savages, i. 374 ; detestation of in-
cest by Australian savages, ii. 154.

Greyhounds, sculptured on Egyptian
monuments, and in the Villa of An-
toninus, i. 29-30 ; modern breed of,
i. 57 ; crossed with the bulldog, by
Lord Orford, ii. 121 ; co-ordination
of structure of, due to selection, ii.
268-269 ; Italian, ii. 276.

Gretness, inherited at corresponding
periods of life, ii. 98.

Grieve, Mr., on early-flowering dah-
lias, i. 445.

Grigor, Mr., acclimatisation of the
Scotch fir, ii. 373.

Groom-Napier, C. O., on the webbed
feet of the otter-hound, i. 55.

" Grosses-gorges," (pigeons), i. 171.

Ground-tumbler, Indian, i. 186.

Grouse, fertility of, in captivity, ii.
192.

Gronland, hybrids of ^Eg'dops and
wheat, ii. 138.

Grus montigresia, cinerea, and Anti-
gone, ii. 192.

Guanacos, selection of, ii. 231.

Guans, general fertility of, in captiv-
ity, ii. 191.

Guelder-rose, ii. 225.

GUELDERLAND fowls, i. 278.

Guiana, selection of dogs by the In-
dians of, ii. 250.

Guinea fowl, i. 355; feral in Ascen-
sion and Jamaica, i. 233, ii. 47 ; in-
diil'erence of to change of climate, ii.
197.

Guinea pig, ii. 36, 186.

Guldenstadt, on the jackal, i. 38.

Gull, herring, breeding in confine-
ment, ii. 193.

Gulls, general sterility of, in captiv-
ity, ii. 193.

Gulo, sterility of, in captivity, ii. 186.

Gunther, A., on tufted ducks and
geese, i. 332 ; on the regeneration of
lost parts in batrachia, ii. 26.

Gurnet, Mr., owls breeding in cap-
tivity, ii. 188 ; appearance of " black-
shouldered" among ordinary pea-
cocks, i. 351.

Habit, influence of, in acclimatisation,

ii. 376-380.
Habits, inheritance of, ii. 473.
Uackel, on cells, ii. 444 ; on the dou-

ble reproduction of medusas, ii. 460 ;
on inheritance, ii. 475.

Hackles, peculiarities of, in fowls, i.
307.

Hair, on the face, inheritance of, in
man, ii. 13; peculiar lock of, inhe-
ited, ii. 14 ; growth of, under stimu-
lation of skin, ii. 393 ; homologous
variation of, ii. 391 ; development of,
within the ears and in the brain, ii.
468.

Hair and teeth, correlation of, ii. 393-
396.

Hairy family, corresponding period of
inheritance in, ii. 98.

Half-castes, character of, ii. 63.

Half-lop rabbits figured and de-
scribed, i. 135-136 ; skull of, i. 149.

llti'ottnx leiiroc, phalns, copulating in
captivity, ii. 188.

Hall am, Col., on a two-legged race of
pigs, ii. 13.

Hamburgh fowl, i. 276, 317 ; figured,
i. 277.

Hamilton, wild cattle of, i. 107.

Hamilton, Dr., on the assumption of
male plumage by the hen pheasant,
ii. 68.

Hamilton, F. Buchanan, on the shad-
dock, i. 403 ; varieties of Indian cul-
tivated plants, ii. 309.

Hancock, Mr., sterility of tamed
birds, ii. 190-192.

Handwriting, inheritance of peculi-
arities in, ii. 14.

Hanmer, Sir J., on selection of flower
seeds, ii. 247.

Hansell, Mr., inheritance of dark
yolks in ducks' eggs, i. 339.

Harcourt, E. V., on the Arab boar-
hound, i. 30 ; aversion of the Arabs
to dun-coloured horses, i. 73.

Hardy, Mr., effect of excess of nou-
rishment on plants, ii. 310.

Hare, hybrids of, with rabbit, i. 132 ;
sterility of the, in confinement, ii.
187 ; preference of, for particular
plants, ii. 281.

Hare-lip, inheritance of, ii. 36.

Harlan, Dr., on hereditary diseases,
ii. 16.

Harmer, Mr., on the number of eggs
iu a codfish, ii. 453.

Harvey, Mr., monstrous red and
white African bull, i. 115.

Harvey, Prof., singular form of Be-
gonia frigida, i. 440 ; effects of cross-
breeding on the female, i. 485; mon-
strous saxifrage, ii. 203.

Hasora wheat, i. 378.

Hautbois strawberry, i. 425.

Hawker, Col., on call or decoy ducks,
i. 340.

Hawthorn, varieties of, i. 437-438 ;
pyramidal, i. 435 ; pendulous hybrid-
ised, ii. 29 ; changes of, by age, i. 438,
465; bud-variation in the, i. 453;
flower buds of, attacked by bull-
finches, ii. 280.

INDEX.

i39

Hates. Dr., character of Esquimaux
dogs, i. 36.

Haywood, W., on the feral rabbits of
Porto Santo, i. 14:1-144.

Hazel, purple-leaved, i. 135. 474, ii.
887.

Head of wild boar and Yorkshire piir.
figured, i. 93.

Head and limbs, correlated variability
of, ii. 389.

Headache, inheritance of. ii. 101.

Heartsease, i. 442-444; change pro-
duced in the. by transplantation, i.
•4(14 : reversion in. ii. 45. 63 : effects
of selection on, ii. 243 ; scorching of,
ii. 277 : effects of seasonal condi-
tions on the. ii. 330 ; annual varieties
of the. ii. 367.

Heat, effect of, upon the fleece of
sheep, i. 124.

Heber, Bishop, on the breeding of the
rhinoceros in captivity, ii. 184.

Hebrides, cattle of the, i. 103 ; pigeons
of the. i. 223.

Heek, O., on the plants of the Swiss
lake-dwellinus. i. 373. ii. 215, 427; on
the cereals, i. 381-384 : on the peas,
i. 393 : on the vine growing in Italy
in the bronze ase, i.400.
ii. 338.

BemerocaRia fuiva and flara, inter-
changing by bud-variation, i. 4<i4.

Hemlock, yields no conicine in Scot-
land, ii. 331.

Hemp, differences of, in various parts
of India, ii. 201 : climatal difference
in products of, ii. 331.

Hemtseed, effect of, upon the colour
of birds, ii. 337.

Hermaphrodite flowers, occurrence
of. in Maize, i. 387.

Hen. assumption of male characters
by the. ii. 68, 72 ; development of
spurs in the, ii. 382.

" Henries,'' or hen-like male fowls, i.
305.

Henry, T. A., a variety of the ash,
produced by grafting, i. 473 ; cross-
ing of species of Jihododendroii and
Arabis, i. 480-481.

Henslow, Prof., individual variation
in wheat, i. 379 ; bud-variation in the
Austrian bramble rose, i. 457 ; par-
tial reproduction of the weeping ash
by seed, ii. 30.

Hepatica, changed by transplanta-
tion, i. 464.

Herbert, Dr., variations of Viola
grandiflora, i. 443 ; bud-variation in
camellias, i. 453 ; seedlings from re-
verted Oyfimw Adami, i. 466; cross-
es of Swedish and other turnips, ii.
118 ; on hollyhocks, ii. 1.35 ; breeding
of hybrids, ii. 163 ; self-impotence in
hybrid hippeastrums, ii. 171-172 : hy-
brid GRadtolvs, ii. 172; on /.■/i/n/-
ranthes Candida, ii. 200; fertility of
the crocus, ii. 211 : on contabescence,
ii. 202 ; hybrid Jihododendron, ii. 320.

IIerc tLANEiM, figure of a pig found
in, i. 88.

Heron. Sir R., appearance of •'black-
shouldered " among ordinary pea-
cocks, i. 351 ; non-inheritance of
monstrous characters by goldfish, i.
357: crossing of white and coloured
Angora rabbits, ii. 117: crosses of
solid-hoofed pigs, ii. 117.

//, /■//, stesfa&ciatus and grist us, ii. 186.

Hbuslnqeb, on the sheep of the Taren-
fino, ii. 275: on correlated constitu-
tional peculiarities, ii. 406.

Hewitt. Mr., reversion in Bantam
cocks, i. 290; degeneration of silk
fowls, i. 294 : partial sterility of hen-
like male fowls, i. 305; production
of tailed chickens by rumpless fowls,
i. 313: on taming and rearing wild
ducks, i. 336. ii. 282. 319; conditions
of inheritance in laced Sebright ban-
tams, ii. 34 : reversion in rumpless
fowls, ii. 44: reversion in fowls by
age, ii. 54 ; hybrids of pheasant and
fowl. ii. 61. 88 : assumption of male
characters by female pheasants, ii.
68 ; development of latent characters
in a barren bantam hen, ii. 72 : mon-
grels from the silk fowl, ii. 87 ; ef-
fects of close interbreeding on fowls,
ii. 154-155: on feathered-legged ban-
tams, ii. 383.

Hieeeiit, Mr., on the pigs of the Shet-
land Islands, i. 92.

Highland cattle, descended from Bos
longifrons, i. 104.

Hildebrand, Dr.. on the fertilisation
of Orcflidece, i. 4S3: occasional ne-
cessary crossing of plants, ii. 114; on
Primula sinensis and Oxcuis rosea, ii.
163; on Oorydalis cava. ii. 164.

Hill. K.. on the Alco, i. 45 ; feral rab-
bits in Jamaica, i. 140-141; feral pea-
cocks in Jamaica, i. 233 : variation
of the Guinea fowl in Jamaica, i. 355 ;
sterility of tamed birds in Jamaica,
ii. 192.

Himalaya, range of gallinaceous birds
in the, i. 237.

Himalayan rabbit, i. 134, 136-139;
skull of, i. 150.

Himalayan sheep, i. 121.

Hindmaksh. Mr., on Chillingham cat-
tle, i. 108.
• IIinkel Tatjbe," i. 176-177.

II inn y and mule, difference of, ii. 88.

Bwparion, anomalous resemblance to
in horses, i. 67.

Eippeastrum, hybrids of, ii. 171-172.

Hive-bees, ancient domestication of,
i. 868; breeds of. i. 359: smaller
when produced in old combs, i. 359 ;
variability in. i. 1359 ; crossing of Li-
eurian and common, i. 360.

" Hocker-Taube," i. 175.

Hobbs, Fisher, on interbreeding pigs,
ii. 151.

Hodgkin. Dr., on the attraction of
foxes by a female Dingo, i. 45 ; ori-

540

IXDEX.

gin of the Newfoundland dog, i. 58 ;
transmission of a peculiar lock of
hair, ii. 14.

Hodgson, Mr., domestication of Gttnis
primcevus, i. 40: development of
a fifth digit in Thibet mastiffs, i. 50 :
number of ribs in humped, cattle, i.
102 : on the sheep of the Himalaya,
i. 120 : presence of four mamma.' in
sheep, i. 121 : arched nose in sheep,
ibid. : measurements of the intes-
tines of goats, i. 129; presence of in-
terdigital pits in goats, i. 128; dis-
use a cause of drooping ears. ii. SG2.

Hofacker. persistency "of colour in
horses, i. 6s. ii. 33 : production of dun
horses from parents of different col-
ours, i. 78 ; inheritance of peculiari-
ties in handwriting, ii. 14 ; hereditary
in a one-horned stag, ii. 22; on con-
sanguineous marriages, ii. 153.

Hog, Red River, ii. 184.

Hogg. Mr., retardation of breeding in
cows by hard living, ii. 140.

Holland. Sir H., necessity of inheri-
tance, ii. 11 ; on hereditary diseases,
ii. 16 ; hereditary peculiarity in the
eyelid, ii. 17 : morbid uniformity in
the same family, ii. 27 ; transmission
of hydrocele through the female, ii.
70 ; inheritance of habits and tricks,
ii. 472.

Hollt, varieties of the, i. 434, 435;
bud-rerersion in. i. 4G1 ; yellow-ber-
ried, ii. 31. 379.

Hollyhock, bud-variation in. i. 454 :
noncrossing of double varieties of,
ii. 135 ; tender variety of the, ii.
374.

Homer, notice of geese, i. 347; breed-
ing of the horses of .Eneas, ii. 245.

Homologous parts, correlated varia-
bility of, ii. 387-399, 425-426; fusion
of, ii. 470; affinity of, ii. 407-411.

Hoofs, correlated with hair in varia-
tion, ii. 393.

Hook-billed duck, skull figured, i.
340.

Hooker, Dr. J. D., forked shoulder-
stripe in Syrian asses, i. S3: voice of
the cock in Sikkim, i. 313: use of
Arum-roots as food, i. 371 ; native
useful plants of Australia, i. 375;
wild walnut of the Himalayas, i..
420 ; variety of the plane tree, i.
430: production of Thuja orientalis
from seeds of T. pendvla, ibid. ;
e-insular form of Begonia fngida. i.
44U: reversion in plantsruh wild,
ii. 48; on the sugar-cane, ii. 206;
on Arctic plants, ii. 310 ; on the oak
grown at the Cape of Good Hope, ii.
331 ; on Rhododendron ci/iatam, ii.
334 ; stock and mignonette, perennial
in Tasmania, ii. 367.

Hopklrk, Mr., bud-variation in the
rose, i. 457; in MirabUis jalapa, i.
459: in Oonioivuhu tricolor, i. 4S9.

HoENBEAai, heterophyllous, i. 436.

Horned fowl, i. 278; skull figured, L
320.

Hornless cattle in Paraguay, i. 118.

Horns of sheep, i. 120-121 ; correlation
of. witu fleece in sheep, ii. 393 ; cor-
relation of, with the skull, ii. 4i 1 ;
rudimentary in young polled cattle,
ii. 379: of goats, i. 128. ■

Horses, in Swiss lake-dwellings, i. 66 ;
different breeds of, in Malay Archi-
pelago, ibid. ; anomalies in osteolo-
gy and dentition of, i. 67-68; mutual
fertility of different breeds, i. 68;
feral, i. 69 ; habit of scraping away
snow. i. 70 ; mode of production of
breeds of, i. 72 ; inheritance and di-
versity of colour in, i. 73 ; dark
stripes in. i. 74-S1 ; ii. 421 : dun-co-
loured, origin of, i. 78 : colours of
feral, i. 79^80 ; effect of fecundation
by a Quagga on the subsequent pro-
geny of, i. 4S4; inheritance of pecu-
liarities in, ii. 20; polydactylism in,
ii. 24: inheritance of colour in. ii.
33 ; inheritance of exostoses in legs
of, ii. 35 ; reversion in, ii. 47. 57 :
hybrids of, with ass and zebra, ii.
57 ; prepotency of transmission in
the sexes of, ii. 85 ; segregation of,
in Paraguay, ii. 129 : wild species of,
breeding in captivity, ii. 184 : curly,
in Paraguay, ii. 248, 392 ; selection
of, for trifling characters, ii. 253 ; un-
conscious selection of, ii. 256, 257:
natural selection in Circassia, ii. 272 ;
alteration of coat of, in coal-mines, ii.
336 : degeneration of, in the Falkland
Islands, ii. 336 : diseases of, caused by
shoeing, ii. 362 ; feeding on meat, ii.
866; white and white-spotted, poi-
soned by mildewed vetches, ii. 405 ;
analogous variations in the colour
of, ii. 419 ; teeth developed on palate
of, ii. 468 ; of bronze period in Den-
mark, ii. 510.

Horse-chesnut, early, at the Tniler-
ies, i. 436; tendency to doubkness
in, ii. 205.

Horse-radish, general sterility of the,
ii. 208.

"Houdah," a French sub-breed of
fowls, i. 278.

Howard, C, on an Egyptian monu-
ment, i. 17; on crossing sheep, ii.
120, 150.

Hug, on the Emperor Khang-hi. ii.
248 : Chinese varieties of the bam-
boo, ii. 309.

Humboldt, A., character of the Zam-
bos, ii. 63 ; parrot speaking the lan-
guage of an extinct tribe, ii. 189 ; on
Pulex penetrans, ii. 332.

Humidity, injurious efl'ect of, upon
horses, i. 71.

Humphreys, Col., on Ancon sheep, i.
126.

Hungarian cattle, i. 103.

Hunter, John, period of gestation in
the dog, i. 44 ; on secondary sexual

IXDEX.

INTERCROSSING.

541

characters, i. 220; fertile crossing
of Anier ferua and Hie domestic
goose, i. 347 : inheritance of peculi-
arities in gestores veil! 3k vLlh
assumption of male characters by the
human female, ii. (is : period of ap-
pearance of hereditary diseases, ii.
!)D ; graft of the spur of a cock upon
it- comb. ii. 356; on the stomach of
Larvs trldentatus. ii. 364; double-
tailed lizards, ii. 409.

Hunter. W., evidence against the in-
fluence of imagination upon the off-
spring, ii. 318.

Hutton. Capt., on the variability of
the silk -moth. i. 365 ; on the number
of species of silkworms, i. 863 ;
markings of silkworms, i. 304 ; do-
mestication of the rock-pisceon in
India, i. 227 : domestication and
crossini of Qauus bankiva, i. 286.

Hutchinson. Col., liability of dogs to
distemper, i. 51.

HrxLET, Prof, on the transmission
of polydactylism, ii. 24 ; on uncon-
scious selection, ii. 386: on correla-
tion in the mollusca. ii. 300 ; on gem-
mation and fission, ii. 431 ; develop-
ment of star-fishes, ii. 430.

Htacinths, i. 445-147: bud-variation
in, i. 463; graft-hybrid by union of
half-bulbs of, i. 474; white, repro-
duced by seed, ii. 32; red. ii. 877,
403 : varieties of, recognisable by
the bulb. ii. 303.

Hyacinth, feather, ii. 225, 330.

Byacinthw orientalis, i. 370.

Hybiscus syriacus, ii. 313.

Hybrids, of hare and rabbit, i. 132;
of various species of 6fattus, i. 288-
286 : of almond, peach, and nectar-
ine, i. 40^ ; naturally produced, of
species of Cy/i-*n.<, i. 488; from twin-
seed of Fuchsia coccinea ami/
i. 400; reversion of, i. 471-473, ii.
50, 64-63 ; from mare, ass, and ze-
bra, ii. 53; of tame animals, wild-
neas of, ii. 61, 6-2; female instincts
of sterile male, ii. 6!) ; transmission
and blending of characters in, ii.
117-120; breed better with parent
species than with each other, ii. 168 ;
self-impotence in, ii. 171, 173 : read-
ily produced in captivity, ii. 184.

Hybridisation, singular effects of, in
oranges, i. 406; of cherries, i. 4ls;
difficulty of. in OucurbitcE, i. 358 ;
of roses, i. 431.

Hybridism, ii. 217, 232; the cause of
a tendency to double flowers, ii.
171; in relation to pangenesis, ii.
461.

Hybridity in cats, i. 66-61 ; supposed
of peach and nectarine, i. 412.

Hydra, i. 440, ii. 363, 430.

Hydrangea, colour of flowers of, in-
fluenced by alum, ii. 335.

Hydrocele, ii. 70.

Hydrocephalus, ii. 355.

Hypericum calycintim, ii. 207.
Hypericum erupum, ii. 275, 405.
Hypbr.metamorph.osis, ii. 440.
Hypermetropia, hereditary, ii. 17.

Ichthyopterygia, number of digits
in the, ii. 26.

Hex (ujiiifii'iiiii), ii. 31.

Imagination, supposed effect of, on
offspring, ii. 318.

Imatophyuum miniatum, bud-varia-
tion in, i. 403.

Incest, abhorred by savages, ii. 154.

Incubation, by crossed fowls of non-
sitting varieties, ii. 50-60.

India, "striped horses of. i. 77 ; piirs
of, i. 87, 99 : breeding of rabbits in,
i. 140: cultivation of pigeons in, i.
260-251.

Individual variability in pigeons, i. •
195-198.

Ingledew, Mr., cultivation of Euro-
pean vegetables in India, ii. 206.

" Indische Taube," i. 170.

Inheritance, ii. 9-107, 444-147, 474-
481 ; doubts entertained of by some
writers, ii. 11 ; importance of to
breeders, 11-12; evidence of, deriv-
ed from statistics of chances, 14 ; of
peculiarities in man. 14-17, 21-27 ; of
disease, 16-18, 27 ; of peculiarities in
the eye, 17-10; of deviations from
symmetry, 22; of polydactylism, 22-
26 ; capriciousness of, 28-34, 30 ; of
mutilations, 34-37; of congenital
monstrosities, 36 ; causes of absence
of, 37-39 : by reversion or atavism,
41-31 : its connexion with fixedness
of character, 81-81; affected by pre-
potency of transmission of character,
84-92; 'limited by sex, 92-97; at cor-
responding periods of life, 07-103 ;
summary of the subject of, 103-107;
laws of, the same in seminal and
bud varieties, i. 491 ; of characters
in the horse, ii. 20-21 ; in cattle, i.
Ill : in rabbits, i. 135 ; in the peach,
i. 409 ; in the nectarine, ibid. ; in
plums, i. 418 ; in apples, i. 421 ; in
pears, i. 422 ; in the pansy, i. 444 ; of
primary characters of Cwumba hvia
in crossed pigeons, i. 245; of peculi-
arities of plumage in pigeons, i. 103-
199; of peculiarities of foliage in
trees, i. 435 ; effects of, in varieties
of the cabbage, i. 391.

Insanity, inheritance of. ii. 16, 103.

Insects, regeneration of lost parts in,
ii. 26. 354 ; agency of, in fecundation
of larkspurs^ ii. 33; effect of chang-
ed conditions upon, ii. 192 ; sterile
neuter, ii. 226-227 ; monstrosities in,
ii. 324, 468.

Instincts, defective, of silkworms, i.
366.

Interbreeding, close, ill effects of, ii.
1 13-162, 213.

Intercrossing, of species, as a cause
of variation, i. 231 ; natural, of plants,

542

INTERDI6ITAL.

INDEX.

i. 404; of species of Canidfe and
breeds of dogs, i. 40-48 ; of domestic
and wild cats. i. 60-01 ; of breeds of
pigs, i. 92, 101 ; of cattle, i. 100 ; of
varieties of cabbage, i. 391 ; of peas,
i. 393, 397 ; of varieties of orange, i.
405; of species of strawberries, i.
422-424; of Cucwrbitas, i. 430-431 ; of
flowering plants, i. 438 ; of pansies, i.
442-443.

Interdigital pits, in goats, i. 128.

Intermarriages, close, ii. 152-153.

Intestines, elongation of, in pigs, i.
95 ; relative measurements of parts
of, in goats, i. 129 ; effects of chang-
ed diet on, ii. 304.

Ipomtxa purpurea, ii. 159.

Ireland, remains of Bosfnmtosus and
longifrons found in, i. 105.

Iris, hereditary absence of the, ii. 19 ;
hereditary peculiarities of colour of
the, ibid.

Irish, ancient, selection practised by
the, ii. 240.

Iron period, in Europe, dog of, i. 31.

Islands, oceanic, scarcity of useful
plants on, i. 375.

Islat, pigeons of, i. 225.

Isolation, effect of, in favour of selec-
tion, ii. 282.

Italy, vine growing in, during the
bronze period, i. 400.

Ivy, sterility of, in the north of Eu-
rope, ii. 207.

Jack, Mr., effect of foreign pollen on
grapes, i. 480.

Jackal, i. 3S, 41, 44; hybrids of, with
the dog, i. 40-47 ; prepotency of, over
the dog, ii. 88.

Jacobin pigeon, i. 190, 254.

Jacquemet-Bonnefort, on the mul-
berry, i. 403.

Jaguar, with crooked legs, i. 30.

Jamaica, feral dogs of, i. 41 ; feral pigs
of, i. 99 ; feral rabbits of, i. 140.

Japan, horses of, i. 71.

Japanese pig (figured), i. 90.

Jardine, Sir W., crossing of domes-
tic and wild cats, i. 60.

Jarves, J., silkworm in the Sandwich
islands, i. 363.

Java, Fantail pigeon in, i. 183.

Javanese ponies, i. 71, 77.

Jemmy Button, i. 373.

Jenyns, L., whiteness of ganders, i.
348 ; sunfish-like variety of the gold-
fish, i. 358.

Jerdon, J. C, number of eggs laid by
the pea-hen, ii. 141 ; origin of domes-
tic fowl, i. 287.

Jersey, arborescent cabbages of, i.
389.

Jessamine, i. 473.

Jeitteles. Hungarian sheep-dogs, i.
37; crossing of domestic and "Wild
cats, i. 60.

Joitn, King, importation of stallions
from Flanders by, ii. 246.

Johnson, D., occurrence of stripes on
young wild pigs in India, i. 99.

Jordan, A., on Vibert's experiments
on the vine, i. 401 ; origin of varie-
ties of the apple, i. 422 ; varieties of
pears found wild in woods, ii. 313.

Jourdan, parthenogenesis in the silk
moth, ii. 430.

Juan de Nova, wild dogs on, i. 41.

Juan Fernandez, dumb dogs on, i.
41.

Juglans rec/ia, i. 429.

Jukes, Prof , origin of the Newfound-
land dog, i. 58.

Julien, Stanislas, early domestication
of pigs in China, i. 89 ; antiquity of
the domestication of the silk-worm
in China, i. 362.

Jumpers, a breed of fowls, i. 278.

Juniper, variations of the, i. 435, 13S.

Juniperus suedca, i. 435.

JttssuBa gratuZifldra, ii. 208.

Jussieu, A. de, structure of the pap-
pus in Carthamws, ii. 381.

Kail, Scotch, reversion in, ii. 45.
"Kala-par" pigeon, i. 176.
Kales, i. 389.

Kalm, P., on maize, i. 388, ii. 370: in-
troduction of wheat into Canada, i.

380; sterility of trees growing in

marshes and dense woods, ii. 207.
"Kalmi Lotan," tumbler pigeon, i.

180.
Kane, Dr., on Esquimaux dogs, i.

34.
Karakool sheep, i. 124.
Karkeek, on inheritance in the horse,

ii. 20.
" Karmeliten Taube," i. 193.
Karsten on Pulex penetrans, ii. 333.
Kattywar horses, i. 77.
Keeley, R., pelorism in Galeobdolon

luti urn, ii. 78.
Kerner on the culture of Alpine

plants, ii. 199.
Kestrel, breeding in captivity, ii.

188.
"Khandesi," i. 174.
Khang-hi, selection of a variety of

rice by, ii. 248.
Kiang, ii. 60.

Kidd, on the canary bird, i. 356, ii. 99.
Kidney Bean, i. 447 ; varieties of, ii.

309, 332.
Kidneys, compensatory development

of the, ii. 361; fusion of the, ii. 409;

shape of, in birds, influenced by the

form of the pelvis, ii. 413.
King, Col., domestication of rock

doves from the Orkneys, i. 225, 227.
King, P. S., on the Dingo, i. 34, 41-

42.
Kirby and Spence on the growth of

galls, ii. 342.
Kirghisian sheep, i. 124.
Kite, breeding in captivity, ii. 188.
Kleine, variability of bees, i. 359.
Knight, Andrew, on crossing horses

INDEX.

LE C0UTEUR.

543

of different breeds, i. 68; crossing va-
rieties of peas. i. 893, ii. 120; persist-
ency of varieties of pe;is. i. 896; ori-
gin of the peach, i. KIT : hybridisation
of the morello by the Elton cherry, i.
418; on seedling cherries, ibid.; va-
riety of the apple not attacked by
coccus, i. 4-21 ; intercrossing of straw -
berries, i. 4-23 : broad variety of the
cock's comb, i. 430 : bud-variation in
the cherry and plum, i. 450, 451 ;
crossing of white and purple grapes,
i. 472 ; "experiments in crossing ap-
ples, i. 48-2, ii. 160 : hereditary dis-
ease in plants, ii. 20; on interbreed-
ing.ii.145: crossed varieties of wheat.
il. 161; necessity of intercrossing in
plants, ii. 214 ; on variation, ii. 300-
310; effects of grafting, i. 404, ii.
330 ; bud-variation in a plum. ii. 347 ;
compulsory flowering of early pota-
toes, ii. 412 ; correlated variation of
head and limbs, ii. 380.

Knox. Mr., breeding of the eagle owl
in captivity, ii. 188.

Kocn, degeneracy in the turnip, i.
302.

Kohlrabi, i. 3S9.

Kolreuter. reversion in hybrids, i.
471. ii. 50: acquired sterility of cross-
ed varieties of plants, i. 431. ii. 127;
absorption at Mirabilis vulgaris by
M. 'iiii'jijiiirii. ii. 112; crosses of spe-
cies of verbascum, ii. 118, 134 ; on
the hollyhock, ii. 135 ; crossing vari-
eties of tobacco, ii. 130; benefits of
crossing plants, ii. 102, 214 ; self-im-
potence in Verbascum, ii. 160, 170;
effects of conditions of growth upon
fertility in Mirabilis, u. 200; great
development of tubers in hybrid
plants, ii. 210; inheritance of plasti-
city, ii. 201 ; variability of hybrids of
Mirabilis, ii. 320: repeated crossing
a cause of variation, ii. 323 : number
of pollen grains necessary for fertili-
zation, ii. 436,

" Krauseschwein." i. 88.

Krohn, on the double reproduction of
Medusa1, ii. 460.

"Kropf-Tauben," i. 171.

Labat. on the tusks of feral boars in

the West Indies, i. 90 : on French

wheat grown in the West Indies, ii.

870 : on the culture of the vine in the

West Indies, ii. 371.
Laburnum. Adam's, see Cytisus

Adam*: oak-leaved, reversion of, i.

450 : pelorism in the, ii. 415 ; Water-

er'a, i. 468.
Lvchmann. on gemmation and fission,

ii. 430.
Lachnanthes tincioria, ii. 275. 405.
Lactation, imperfect, hereditary, ii.

17; deficient, of wild animals in

captivity, ii. 104.
Ladrone islands, cattle of, i. 109.

Laing. Mr., resemblance of Norwegi-
an and Devonshire cattle, i. 106.

Lake-Dwellings, sheep of, i. 119, ii.
510: cattle of. ii. 510: absence of the
fowl in, i. 297: cultivated plants of,
i. 373, ii. 510, 572; cereals of, i. 882-
385; peas found in, i. 393; beans
found in, i. 398.

Lamare-Piquot, observations on half-
bred North American wolves, i. 35.

Lambert, A. B.. on Thuja pendula or
filiformis, i. 430.

Lambert family, ii. 12. 08.

Lambertte on strawberries, i. 423,
421: five-leaved variety of Fm'jt'/ia
coUina, i. 425.

Landt, L.. on sheep in the Faroe is-
lands, ii. 129.

La Plata, wild dogs of, i. 41 : feral
cat from. i. 64.

Larch, ii. 373.

Larkspurs, insect agency necessary
for the full fecundation of, ii. 33.

LarUB nrq, litiin/s. ii. 102.

Lams tridactylus, ii. 864.

Lasteeye. merino sheep in different
countries, i. 125.

Latent characters, ii. 08-75.

Latham, on the fowl not breeding in
the extreme north, ii. 197.

Lathyrus, ii. 52.

Lathyrus aphaca, ii. 412.

Lathyrus odoratus, ii. 32, 115, 118, 374,
469.

La Touche. J. D., on a Canadian ap-
ple with dimidiate fruit, i. 471.

"Latz-Taube," i. 190.

Laugher pigeon, i. 191, 252.

Lauras sassafras, ii. 331.

Lawrence. J., production of a new
breed of fox-hounds, i. 50 : occur-
rence of canines in marcs, i. 07 : on
three-parts-bred horses, i. 72 : on in-
heritance in the horse, ii. 20-21.

Lawson, Mr., varieties of the potato,
i. 398.

Laxton, Mr., bud-variation in the
gooseberry, i. 451 : crossing of varie-
ties of the pea, i. 477 ; double-llow-
ered peas, ii. 205.

Latard, E. L., resemblance of a
Caffre dog to the Esquimaux breed,
i. 39, ii. 345 ; crossing of the domes-
tic cat with F, lis t 'affra, i. 61 : feral
pigeons in Ascension, i. 233 ; domes-
tic pigeons of Ceylon, i. 251 ; on
Gattus Stardeyi, i. 284; on black-
skinned Ceylonese fowls, i. 810.

Le Compte family, blindness inherit-
ed in, ii. 100.

Lecoq, bud-variation in Mirabilis ja-
lapa, i. 450; hybrids of Mirabilis, i.
472, ii. 200, 320; crossing in plant*,
ii. 158; fecundation ot Passiflora,
ii. 170; hybrid Gladiolus, ii. l^o;
sterility of Ranunculus flcaria, ii.
208; villosity in plants, ii. 335;
double asters, ii. 380.
i Le Couteur, J., varieties of wheat, i.

544

INDEX.

378-330; acclimatisation of exotic
wheat in Europe, i. 380; adaptation
of wheat to soil and climate, ibid. ;
selection of seed-corn, i. 383; on
change of soil, ii. 181 ; selection of
wheat, ii. 281 ; natural selection in
wheat, ii. 242 ; cattle of Jersey, ii.
2S3.

Ledger, Mr., on the Llama and Alpa-
ca, ii. 252.

Lee, Mr., his early culture of the
pansy, i. 443.

Leersia oryzoides, ii. 115.

Lefour, period of gestation in cattle,
i. 111.

Legs, of fowls, effects of disuse on, i.
327-329; characters and variations
of, in ducks, i. 343-346; fusion of,
ii. 409.

Leguat, cattle of the Cape of Good
Hope, i. 112.

Lehmann, occurrence of wild double-
flowered plants near a hot spring,
ii. 205.

Leighton, W. A., propagation of a
weeping yew by seed, ii. 31.

Leitner^ effects of the removal of an-
thers, ii. 205.

Lemming, ii. 186.

Lemoine, variegated Symphytum and
Phlox, i. 461.

Lemon, i. 403, 404 : orange fecundated
by pollen of the. i. 479.

Lemurs, hybrid, ii. 187.

Leporides, ii. 124, 187.

Lepsius, figures of ancient Egyptian
dogs, i. 29; domestication of pigeons
in ancient Egypt, i. 249.

Leptoies, ii. 166.

Lepus glacialis, i. 140.

Lepics magelianicus, i. 141.

Lepus nigripes, i. 136.

Lepus tibetauu*, i. 140.

Lepus variabilis, i. 139.

Lereboullet, double monsters of
fishes, ii. 408.

Leslie, on Scotch wild cattle, i. 103.

Lesson, on Lepus magelianicus, i. 141.

Leuckart on the larva of Cecidomyi-
da>, ii. 431.

Lewis, G., cattle of the West Indies,
ii. 277.

Lherbette and Quatrefages, on the
horses of Circassia, ii. 129, 273.

Liebig, differences in human blood,
according to complexion, ii. 333.

Liebreich, occurrence of pigmentary
retinitis in deaf-mutes, ii. 395.

Lichens, sterility in, ii. 20S.

Lichtenstein, resemblance of Bos-
jesman's dogs to Canis mesomelas,
i. 39 ; Newfoundland dog at the
Cape of Good Hope, i. 51.

Lilacs, ii. 200.

Liliace.e, contabescence in, ii. 202.

LUium candidum, ii. 169.

Limbs, regeneration of. ii. 450-451.

Limbs and head, correlated variation
of, ii. 3S9.

Lime, effect of, upon shells of the inol-
lusca, ii. 333.

Lime tree, changes of by age, i. 433,
465.

Limitation, sexual, ii. 92-96.

Limitation, supposed, of variation,
ii. 497.

Linariq, pelorism in, ii. 76, 80, 415;
peloric, crossed with the normal
form, ii. 91 : sterility of, ii. 203.

Linaria vulgaris and purpurea, hy-
brids of, ii. 119.

Lindlet, John, classification of varie-
ties of cabbages, i. 390; origin of
the peach, i. 407 : influence of soil
on peaches and nectarines, i. 409;
varieties of the peach and nectarine,
i. 413 ; on the New Town pippin, i.
420; freedom of the Winter Majetin
apple from coccus, i. 421 ; production
of monoecious Hautbois strawber-
ries by bud-selection, i. 425 ; origin
of the large tawny nectarine, i. 450 ;
bud-variation in the gooseberry, i.
451 : hereditary disease in plants,
ii. 20; on double flowers, ii. 204;
seeding of ordinarily seedless fruits,
ii. 206'; sterility of Acorus calamus,
ii. 207 ; resistance of individual
plants to cold, ii. 372.

Linnaeus, summer and winter wheat
regarded as distinct species by, i.
380; on the single-leaved strawber-
ry, i. 424 ; sterility of Alpine plants
in gardens, ii. 199; recognition of
individual reindeer by the Lapland-
ers, ii. 303; growth of tobacco in
Sweden, ii. 370.

Linnet, ii. 193.

Linota cannabina, ii. 193.

Li a mi}, ii. 201.

Lion, fertility of, in captivity, ii. 185.

Lipari, feral rabbits of, i. 142.

Livingstone, Dr., striped young pigs
on the Zambesi, i. 99 : domestic
rabbits at Loanda, i. 140 ; use of
grass-seeds as food in Africa, i. 372;
planting of fruit-trees by the Bato-
kas, i. 373 ; character of half-castes,
ii. 63; taming of animals among the
Barotse, ii. 196; selection practised
in South Africa, ii. 251, 253.

Livingstone, Mr., disuse a cause of
drooping ears, ii. 363.

Lizards, reproduction of tail in, ii.
354 ; with a double tail. ii. 408.

Llama, selection of, ii. 252.

Llotd, Mr., taming of the wolf, i.
40 ; English dogs "in northern Eu-
rope, i. 51 ; fertility of the goose in-
creased by domestication, i. 348;
number of eggs laid by the wild
goose, ii. 140 ; breeding of the caper-
cailzie in captivity, ii. 191.

Loanda, domestic rabbits at, i. 140.

Loasa, hybrid of two species of, ii.
123.

Lobelia, reversion in hybrids of, i.
471 ; contabescence in, ii. 202.

INDEX.

MACKENZIE.

545

IstheVw fidgt ik. cardinaUs, ani syphili-
tica, ii. 109.

Lockhart, Dr., on Chinese pigeons,
i. 251.

Locust tree. ii. 831.

Loiselbur-Deslongchamps, origin-
als of cultivated plants, i. 870-371 ;
Mongolian varieties of wheat, i.
878; characters of the car In wheat,
i. 879 ; acclimatisation of exotic
wheat in Europe, i. 380 ; effect of
change of climate on wheat, ibid. ;
on the supposed necessity of the
coincident variation of weeds and
cultivated plants, i. 382; advantage
of change of soil to plants, ii. 180.

Loliwn (emuientum, variable presence
of barbs in, i. 378.

Long-tailed sheep, i. 119, 120.

Loochoo islands, horses of. i. 71.

Lord. J. K.,on Oan&a latrans, i. 33.

"Lori rajah," how produced, ii.
338.

Lorius garnilus, ii. 338.

" Lotan." tumbler pigeon, i. 186.

Loudon.. J. W.. varieties of the carrot.
i. 393 ; short duration of varieties of
peas, i. 396 ; on the glands of peach-
leaves, i. 413 ; presence of bloom on
Russian apples, i. 420 ; origin of
varieties of the apple, i. 422 ; varieties
of the gooseberry, i. 426 ; on the
nut treeTi. 429 ; varieties of the ash,
i. 434 ; fastigate juniper (./. suedea),
i. 435: on Bex aquifdhum ferox,
ibid. ; varieties of the Scotch fir, i.
437; varieties of the hawthorn,
ibid. : variation in the persistency
of leaves on the elm and Turkish
oak, i. 436 : importance of cultivated
varieties, i. 437 ; varieties of Bosa
P/rinod-i-nma, i. 442 ; variation of dah-
lias from the same seed, i. 445 ; pro-
duction of Provence roses from
seeds of the moss rose. i. 456 : effect
of grafting the purple-leaved upon
the common hazel, i. 474 ; nearly
evergreen Cornish variety of the
elm, ii. 373.

Low, G., on the pigs of the Orkney
islands, i. 91-92.

Low, Prof., pedigrees of greyhounds,
ii. 3; origin of the dog, i. 28; bur-
rowing instinct of a half-bred Dingo,
i. 42 : inheritance of qualities in
horses, i. 68; comparative powers of
English race-horses, Arabs, Ac., i.
72: British breeds of cattle, i. 103;
wild cattle of Chartley. i. 108 J effect
of abundance of food on the size of
cattle, i. 11(5: effects of climate on .
the skin of cattle, i. 117, ii 893; on
interbreeding, ii. 115: selection in
Hereford cattle, ii. 259; formation
of new breeds, ii. 295 ; on " sheeted"
cattle, ii. 419.

Lowe, Mr., on hive bees, i. 301.

Lowe. Rev. Mr., on the range of
Pijrus medus and /'. acerba, i. 419.

11 Lowtan " tumbler pigeon, i. 186.
Loxia Tpyrrhvla, ii. 189.

Lubbock. Sir J., developments of the
Ephcmeridas, ii. 438.

Lucas. P., effects of cross-breeding
on the female, i. 485 ; hereditary dis-
eases, ii. 16, 100, 102; hereditary af-
fections of the eye, ii. 18, 19; in-
heritance of anomalies in the human
eye and in that of the horse, ii. 19,
20 ; inheritance of polydactylism, ii.
23; morbid uniformity in the same
family, ii. 2S; inheritance of mutila-
tions, ii. 35 : persistency of cross-
reversion, ii. 49 ; persistency of
character in breeds of animals in
wild countries, ii. 83 ; prepotency of
transmission, ii. 84, 88 ; supposed
rules of transmission in crossing
animals, ii. S8; sexual limitations of
transmission of peculiarities, ii. 93,
94; absorption of the minority in
crossed races, ii. Ill ; crosses with-
out blending of certain characters, ii.
116 ; on interbreeding, ii. 145 ; va-
riability dependent on~rcproduction,
ii. 302; period of action of variabi-
lity, ii. 314: inheritance of deafness
in cats, ii. 396 : complexion and con-
stitution, ii. 403.

Lucaze-Duthiers, structure and
growth of galls, ii. 341, 342. 343.

Luizet. grafting of a peach-almond on
a peach, i. 408.

Lutke, cats of the Caroline Archipe-
lago, i. 64.

Luxuriance, of vegetative organs, a
cause of sterility "in plants, ii. 206,
210.

Ltonnet, on the scission of Nais, ii.
429.

Lysimachia nummuJaria, sterility of,
'ii. 207.

Lythrum, trimorphic species of, ii.
478.

Lythrum salicaria, ii. 223; contabes-
cence in, ii. 202.

Lytta resicaforia, affecting the kid-
neys, ii. 455.

Macacus, species of, bred in captivity,
ii. 187.

Macaulat, Lord, improvement of the
English horse, ii. 258.

M'Clelland, Dr.. variability of fresh-
water-fishes in India, ii. 312.

M'Cot, Prof., on the dingo, i. 39.

M acfayden. influence of soil in pro-
ducing sweet or bitter oranges from
the same seed, i. 404.

Macgillivray, domestication of the
rock-dove, i. 227 ; feral pigeons in
Scotland, i. 233; number of verte-
brae in birds, i. 322; on wild geese,
i. 317; number of eggs of wild and
tame ducks, ii. 140.

Mackenzie, Sir H.. peculiar variety
of the potato, i. 398.

546

MACKENZIE.

INDEX.

MAXILLARIA.

Mackenzie, P., bud-variation in the
currant, i. 452.

MacKinnon, Mr., horses of the Falk-
land islands, i. 70 ; feral cattle of the
Falkland islands, i. 110.

MacKnight, C, on interbreeding cat-
tle, ii. 147.

MacNab, Mr., on seedling weeping
birches, ii. 29 ; non-production of
the weeping beech by seed, ii. 30.

Madagascar, cats of, i. 64.

Madden, H., on interbreeding cattle,
ii. 147.

Madeira, rock-pigeon of, i. 226.

Magnolia grandiflora, ii. 371.

Maize, its unity of origin, i. 385 ; an-
tiquity of, i. 386 ; with husked grains
said to grow wild, ibid. ; variation
of, ibid. ; irregularities in the flow-
ers of, i. 387 ; persistence of varie-
ties, ibid. ; adaptation of to climate,
i. 388, ii. 370 ; acclimatisation of, ii.
377-416; crossing of, i. 480, ii. 132;
extinct Peruvian varieties of, ii. 508.

Malay fowl, i. 275.

Malay Archipelago, horses of, i. 71 ;
short-tailed cats of, i. 64 ; striped
young wild pigs of, i. 90 ; ducks of,
i. 338.

Male, influence of, on the fecundated
female, i. 476-486 ; supposed influ-
ence of, on oflspring, ii. 88.

Male flowers, appearance of, among
female flowers in maize, i. 387.

Malformations, hereditary, ii. 101.

Malm, fertilisation of, i. 4S3, ii. 436.

Mamestra suasa, ii. 193.

Mammjb, variable in number in the
pig, i. 95 ; rudimentary, occasional
full development of, in cows, i. Ill,
ii. 382 ; four present in some sheep,
i. 120; variable in number in rab-
bits, i. 134 ; latent functions of, in
male animals, ii. 69, 382; supernu-
merary and inguinal, in women, ii. 75.

Mangles, Mr., annual varieties of the
heartsease, ii. 367.

Mantell, Mr., taming of birds by the
New Zealanders, ii. 196.

Manu, domestic fowl noticed in the
Institutes of, i. 298.

Manure, eifect of, on the fertility of
plants, ii. 200.

Manx cats, i. 62, ii. 86.

Marcel de Serres, fertility of the os-
trich, ii. 191.

Marianne islands, varieties of Pan-
danus in, ii. 309.

Markham, Gervase, on rabbits, i. 131,
ii. 247..

Markhor, probably one of the parents
of the goat, i. 127.

Marquand, cattle of the channel is-
lands, i. 103.

Marrimpoey, inheritance in the horse,
ii. 20.

Marrow, vegetable, i. 430.

Marry att, Capt., breeding of asses
in Kentucky, ii. 286.

Marsden, notice of Gallus giganteus,
i. 285.

Marshall, Mr., voluntary selection
of pasture by sheep, i. 122; adapta-
tion of wheats to soil and climate, i.
380; " Dutch-buttocked " cattle, ii.
17 ; segregation of herds of sheep,
ii. 129; advantage of change of soil
to wheat and potatoes, ii. 179 ; fash-
ionable change in the horns of cat-
tle, ii. 254; sheep in Yorkshire, ii.
2S4.

Marshall, Prof., growth of the brain
in microcephalous idiots, ii. 466.

Martens, E. Von, on Achalbulla, ii.
71.

Martin, W. C. L., origin of the dog,
i. 28 ; Egyptian dogsj" i. 30 ; barking
of a Mackenzie Paver dog, i. 40-41 ;
African hounds in the Tower me-
nagerie, i. 47 ; on dun horses and
dappled asses, i. 73; breeds of the
horse, i. 66 ; wild horses, i. 69 ; Sy-
rian breeds of asses, i. 81 ; asses
without stripes, i. 82 ; efl'ects of
cross-breeding on the female in
dogs, i. 485 ; "striped legs of mules,
ii. 57.

Martins, defective instincts of silk-
worms, i. 366.

Martins, C, fruit trees of Stockholm,
ii. 369.

Mason, W., bud-variation in the ash,
i. 459.

Masters, Dr., reversion in the spiral-
leaved weeping willow, i. 460 ; on
peloric flowers, ii. 76; pelorisnvin a
clover, ii. 415 ; position as a cause
of pelorism, ii. 414-417.

Masters, Mr., persistence of varieties
of peas, i. 396 ; reproduction of co-
lour in hyacinths, ii. 32 ; on holly-
hocks, ii. 135 ; selection of peas for
seed, ii. 242; on Opuntia leucotricha,
ii. 345 : reversion by the terminal
pea in the pod, ii. 417.

Mastiff, sculptured on an Assyrian
monument, i. 29, ii. 512 ; Tibetan, i.
50-51, ii. 336.

Matthews, Patrick, on forest trees,
ii. 287.

Matthiola annua, i. 479, ii. 31.

Matthiola vncana, i. 458, 479.

Mauchamp merino sheep, i. 127.

Mauduyt, crossing of wolves and dogs
in the Pyrenees, i. 37.

Maund, Mr., crossed varieties of
wheat, ii. 161.

Maupertuis, axiom of " least action,"
i. 24.

Mauritius, importation of goats into,
i. 128.

Maw, G., correlation of contracted
leaves and flowers in pelargoniums,
ii. 398.

Mawz, fertility of Brassica rapa, ii.
201.

MdxUlaria, self-fertilised capsules of,
ii. 166 ; number of seeds in, ii. 453.

MAXILLARIA.

INDEX.

MOORCKOFT.

547

MaxSlaria alro-rubens, fertilisation of,
by M. 8gu U n*. ii. 165.

Maven M., self-iinpotence in Ama-
ryllis, ii. 172.

Meckel, on the number of dibits, ii.
23: correlation of abnormal muscles
in the lee ami arm, ii. 888.

Medus.e, development of, ii. 441, 400.

Meeiian, Mr., comparison of Euro-
pean and American trees, ii. 889.

Mel agris mexicana, i. 352.
bus, ii. 186.

Melons, i. 433-134: mongrel, supposed
to be produced from a twin-seed, i.
469; crossing of varieties of, i. 471),
ii. 135, 160 : inferiority of, in Roman
times, ii. 261 : changes in, by cul-
ture and climate, ii. 331 ; serpent,
correlation of variations in. ii. 398 ;
analogous variations in, ii. 418.

Membranes, false, ii. 355.

Menetries. on the stomach of
graUaria, ii. 364.

Meningitis, tubercular, inherited, ii.
100.

Metagenesis, ii. 439.

Metamorphosis, ii. 139.

Metamorphosis and development, ii.
464, 485.

Metzger, on the supposed species of
wheat, i. 376-377; tendency of wheat
to vary. i. 379 : variation of maize,
i. 386-388: cultivation of American
maize in Europe, i. 388. ii. 410 ; on
cabbages, i. 390-392: acclimatisation
of Spanish wheat in Germany, ii. 3S ;
advantage of change of soil to plants,
ii. 179 : "on rye. ii. 307 : cultivation
of different kinds of wheat, ii. 315.

Mexico, dog from, with tan spots on
the eyes. i. 43 ; colours of feral horses
in, i. 80.

Meten. en sending of bananas, ii. 295.

Mice, grey and white, colours of, not
blended by crossing, ii. 110: rejec-
tion of bitter almonds by, ii. 2S1 ;
naked, ii. 330.

Michaux, v., roan-coloured feral
horses of Mexico, i. 80; origin of
domestic turkey, i. 353; on raising
peaches from seed, i. 409.

Michel, F., selection of horses in me-
diaeval times, ii. 210: horses prefer-
red on account of slight characters,
ii. 253.

Michelt, effects of food on caterpil-
lars, ii. 333: on JBombyx Hesperus, ii.
300.

Microphthalmia, associated with de-
fective teeth, ii. 395.

Middens, Danish, remains of dogs in,
i. 31. ii. 510.

Mignonette, ii. 2S0, 374.

Millet, i. 447.

Mills. J., diminished fertility of mares
when first turned out to grass, ii.
197.

Milne -Edwards, on the development
of the Crustacea, ii. 411.

Milne-Edwards. A., on a crustacean
with a monstrous eye-peduncle, ii.
468.

Miir>i< ,,;,/, r, ii. 183.

Mimuhts luteus, ii. 159.

Minor,' W. C, gemmation and fission
in the Annelida, ii. 430. •

MirabUis, fertilisation of. ii. 436; hy-
brids of, ii. 102, 200, 319.

MirabUis mlapa, i. 459. 472.

MirabUis iongiflira} ii. 112.

MirabUis vulgaris, ii. 112.

Misocampus and Cecidomyia, i. 15. 10.

Mitchell, Dr., effects of the poison
of the rattlesnak". ii. 349.

Mitpord, Mr., notice of the breeding
of horses by Erichthonius, ii. 345.

Moccas Court, weeping oak at. ii. 29.

Mogford, horses poisoned by fool's
parsley, ii. 406.

Moller, L., efl'ects of food on insects,
ii. 339.

Moquin-Tandon, original form of
maize, i. 3S6 ; variety of the double
columbine, i. 439 ; peloric flowers,
ii. 76, 77, 7S, 81 ; position as a cause
of pelorism in flowers, ii. 414 ; ten-
dency of peloric flowers to become
irregular, ii 99 : on monstrosities,
ii. 806; correlation in the axis and
appendages of plants, ii. 386 : fusion
of homologous parts in plants, ii.
405, 409-410 : on a bean with mon-
strous stipules and abortive leaflets,
ii. 412 : conversion of parts of flow-
ers, ii. 469.

Mole, white, ii. 400.

Moll and Gayot, on cattle, i. 103, ii.
121, 255.

Mollusca, change in shells of. ii. 33s.

Monke, Lady, culture of the pansy
by, i. 412.

Monkeys, rarely fertile in captivity,
ii. 1S7.

Monnier, identity of summer and
winter wheat, i. 3S0.

Monster, cyclopean, ii. 409.

Monsters, double, ii. 407-409.

Monstrosities, occurrence of, in do-
mesticated animals and cultivated
plants, i. 440, ii. 306 ; due to persis-
tence of embryonic conditions, ii.
75 ; occurring by reversion, ii. 75-79 ;
a cause of sterility, ii. 203-204 ;
caused by injury to the embryo, ii.
324.

Montegazza. growth of a cock"s-
spur inserted into the eye of an ox,
ii. 443.

Montgomery, E., formation of cells,
ii. 444.

Moor. J. H., deterioration of the horse
in Malasia. i. 71.

Moorcroft. Mr., on ITasora wheat, i.
378; selection of white-tailed yaks,
ii. 249; melon of Easchmir, ii. 833;
varieties of the apricot cultivated in
Ladakh. i. 415 ; varieties of the wal-
nut cultivated in Kaschmir, i. 429.

548

INDEX.

Moore. Mr., on breeds of pigeons, i.

183, 102. 253. 254. 255. 257.
Mooruk, fertility of, in captivity, ii.

191.
Morlot, clogs of the Danish Middens,

i. 31 ; sheep and horse of the bronze

period, ii. 510.
Mormodes ignea, ii. 71.
Morocco, estimation of pigeons in, i.

250.
Morren, C, on pelorism, ii. 77 : in

Calceolaria, ii. 415; non-coineidence

of double flowers and variegated

leaves, ii. 204.
Morris. Mr., breeding of the Kestrel

in captivity, ii. 188.
Morton, Lord, effect of fecundation

by a quagga on an Arab mare, i.

484-485.
Morton, Dr., origin of the dost. i. 23 ;

hybrid of zebra and mare, ii. 5rf.
Moras alba, i. 402.
Moscow, rabbits of, i. 134, 150 : effects

• of cold on pear-trees at, ii. 369.
Mosses, sterility in, ii. 208 ; retro-
gressive metamorphosis in, ii. 433.
Moss-rose, probable origin of, from

Pom centifolia. i. 456; Provence

roses produced from seeds of, i. 45(i.
Mosto, Cada, on the introduction of

rabbits into Porto Santo, i. 141.
Mottling of fruits and flowers, i.

480.
Moufflon, i. 119.
Mountain-ash. ii. 279.
Mouse, Barbary. ii. 186.

" MOVEN-TAUBE,'' i. 184.

Mowbray, Mr., on the eggs of game
fowls, i. 301 ; early pugnacity of
game cocks, i. 303 : diminished fe-
cundity of the pheasant in captivity,
ii. 190.

Mowbray, Mr., reciprocal fecundation
of Pasaiflora (data and racemosa, ii.
169.

Mulattos, character of, ii. 63.

Mulberry, i. 402, ii. 309.

Mule and hinny, differences in the, ii.
88.

Mules, striped colouring of, ii. 57 ;
obstinacy of. ii. 62 ; production of,
among the Romans, ii. 1S7 ; noticed
in the Bible, ii. 244.

Muller, Fritz, reproduction of or-
chids, ii. 166-167 ; development of
Crustacea, ii. 441 ; number of seeds
in a nifi i-i'Uirt'i. ii. 453.

Muller, H., on the face and teeth in
dogs, i. 49, 94. ii. 413.

Muller, J., production of imperfect
nails after partial amputation of the
fingers, ii. 25 : tendency to variation.
ii. 304 ; atrophy of the optic nerve
consequent on destruction of the
eye, ii. 35S : on Janus-like monsters,
ii. 408 ; on gemmation and fission, ii.
430 ; identity of ovules and buds, ii.
431 : special affinities of the tissues,
ii. 455.

Muller, Max, antiquity of agricul-
ture, ii. 294.

Multiplicity of origin of pigeons,
hypotheses of. discussed, i. 230-238.

Muniz, F., on Xiata cattle, i. 111.

Munro, R., on the fertilisation of or-
chids, ii. 165 ; reproduction of Pas-
su flora alal a, ii. 170.

" Murassa" pigeon, i. 178.

Murphy, J. J., the structure of the
eye not producible by selection, ii.
268.

Mu8 atexandritms, ii. 111.

Musa sapientum, CMnensis and Caven-
dishii, i. 452-453.

Muscari camosum, ii. 225, 380.

Muscles, effects of use on. ii. 35S.

Musk duck, feral hybrid of, with the
common duck, i. 233.

Musmon, female, sometimes hornless,
i. 121.

Mutilations, inheritance or non-in-
heritance of, ii. 34-37, 476.

My att. on a five-leaved variety of the
strawberry, i. 425.

Myopia, hereditary, ii. 18.

Myriapoda, regeneration of lost parts
in, ii. 26, 354.

Nails, growing on stumps of fingers,
ii. 472.

Xais, scission of, ii. 429.

Namaquas, cattle of the, i. 112, ii. 251.

Narcissus, double, becoming single
in poor soil, ii. 204.

Xarvaez, on the cultivation of native
plants in Florida, i. 376.

Nasua, sterility of, in captivity, ii.
186.

" Natas," or Xiatas, a South Ameri-
can breed of cattle, i. 113-115.

Nathusius, H. von, on the pigs of the
Swiss lake-dwellings, i. 88-89 ; on
the races of pigs, i. 85-89 ; conver-
gence of character in highly-bred
pigs.i. 95, ii. 291 ; causes of changes in
the form of the pig's skull, i. 93-94 ;
changes in breeds of pigs by cross-
ing, i. 101 ; change of form in the
pig, ii. 337 ; effects of disuse of parts
in" the pig, ii. 360; period of gesta-
tion in the pig. i. 95-96 ; appendages
to the jaw in pigs. i. 98 : on 3ia p!i-
Ctoeps, i. 91 ; period of gestation in
sheep, i. 123 ; on Xiata cattle, i. 113 ;
on short-horn cattle, ii. 147 : on in-
terbreeding, ii. 145 : in the sheep, ii.
149 ; in pigs, ii. 151 ; unconscious
selection in cattle and pigs, ii. 259 ;
variability of highly selected races,
ii. 2S8.

Xato, P., on the Bizzaria orange, i.
470.

Natural selection, its general princi-
ples, i. 12-26.

Nature, sense in which the term is
employed, i. 17.

Naudin, supposed rules of transmis-
sion in crossing plants, ii. 89 ; on the

NECTARINE.

INDEX.

549

nature of hybrids, ii. 6646 : essen-
ces of the species in hybrids, ii. 462-
480; reversion of hybrids, ii. 60, 66-
67: reversion in flowers by stripes
and blotches, ii. 68; hybrids of Li-
n mill vulgaris and purpurea, ii. 119;
pelorismin Limn in. ii. 77. 115; cross-
ing of peloric Linaria with the nor-
ma! form, ii. 91 : variability in ]><i-
tura, ii. 321 ; hybrids of Datura /n-
ri< and stramonium, i. 471; prepo-
tency of transmission of Datura
stramonium when crossed, ii. 87;
on the pollen of MirabUiS and of hy-
brids, i. 407 ; fertilisation of Mirn-
biUs, ii. 43(5; crossing of Chamcu-
rops humiUs and the date palm, i.
479 ; cultivated^ucurbitaeea\ i. 430-
434, ii. 135 : rudimentary tendrils in
gourds, ii. 380; dwarf CueurbiUe, ii.
398 ; relation between the size and
number of the fruit in Cucurbita
pepo\ ii. 412; analogous variation in
Cucurbita!, ii. 418; acclimatisation
of Cucurbitacea?, ii. 37(! : production
of fruit by sterile hybrid Cucurbita-
ceae, ii. 209 ; on the melon, i. 3(i0, ii.
135, 331 : incapacity of the cucumber
to cross with other species, i. 433.
Nectarine, i. 406-414: derived from
the peach, i. 407, 409-412; hybrids
of, i. 408 ; persistency of characters
in seedling, i. 409 ; origin of, i. 410 ;
produced on peach trees, i. 410-111 ;
producing peaches, i. Ill : variation
in, i. 412-413 : bud-variation in, i.
450 ; glands in the leaves of the. ii.
280 : analogous variation in, ii. 418.
Nectary, variations of, in pansies, i.

444.
Nees, on changes in the odour of

plants, ii. 331.
" Negro" cat. i. 03.
Negroes, polydactylism in, ii. 24 : se-
lection of cattle practised by, ii. 250.
Neolithic period, domestication of
Bos Umgifrons and pi 'unit/minx in
the. i. 103-104 : cattle of the. distinct
from the original species, i. 110 ; do-
mestic goat in the, i. 127 ; cereals of
the, i. 881-382.
Nerve, optic, atrophy of the, ii. 358.
Neumeister, on the Dutch and Ger-
man pouter pigeons, i. 172 : on the
Jacobin pigeon, i. 190 : duplication of
the middle flight feather in pigeons,
i. 197 ; on a peculiarly coloured
breed of pigeons. " Staarhalsige
Taube," i. 198: fertility of hybrid
pigeons, i. 235 : mongrels of the
trumpeter pigeon, ii. §6 : period of
perfect plumage in pigeons, ii. 99;
advantage of crossing pigeons, ii.
156.
Neuralgia, hereditary, ii. 101.
New Zealand, feral cats of, i. 04;

cultivated plants of, i. 375.
Newfoundland dog, modification of,
in England, i. 58.

Newman, E., sterility of Sphingidae

under certain conditions, ii. 193,
Newport, G.. non-copulation of !"</-
m wu in confinement, ii. 193; regen-
eration of limbs in myriapoda, ii.
364; fertilisation of the ovule in
batrachia, ii. 435.
Newt, polydactylism in the. ii. 24.
Newton, A., absence of sexual dis-
tinctions in the ColnmbidsB, i. 200:
production of a "black-shouldered"
pea-hen among the ordinary kind, i.
351 ; on hybrid ducks, ii. 198,
Ngami, Lake, cattle of, i. 112.
'•Xiata" cattle, L 113-115; resem-
blance of to Siratht limn. i. 114;
prepotency of transmission of cha-
racter by, ii. 86.
" Nicard " rabbit, i. 131.
Nicholson, Dr., on the cats of An-
tisrua, i. 62; on the sheep of Antigua,
i. 124.
Kicotiana, crossing of varieties and
species of, ii. 136; prepotency of
transmission of characters in spe-
cies of. ii. 87 : contabescence of fe-
male organs in, ii. 203.
Nhcotlana gluUnosa, ii. 136.
Niebuhr, on the heredity of mental
characteristics in some Roman fami-
lies, ii. 85.
Night-blindness, non-reversion to,

ii. 51.
Nilsson, Prof., on the barking of a
young wolf, i. 41 : parentage of Eu-
ropean breeds of cattle, i. 103, 104 ;
on Bosfrontogus, in Scania, i. 104.
Nind, Mr., on the dingo, i. 54.
"Nisusformativus," ii. 353, 354, 355,

426.
Nitzsch, on the absence of the oil-
gland in certain Columba?, i. 182.
Non-inheritance, causes of, ii. 36-39.
" Nonnain " pigeon, i. 190.
Nordmann, dogs of Awhasie, i. 38.
Normandy, pigs of, with appendages

under the jaw, i. 97.
Norway, striped ponies of. i. 76.
Nott and Gliddon on the origin of the
dog. i. 28; mastiff represented on an
Assyrian tomb, i. 29; on Egyptian
clogs, i. 30 ; on the Hare-Indian dog,
i. 35.
Notylia, ii. 168.
Nourishment, excess of, a cause of

variability, ii. 310.
Number, importance of, in selection,

ii. 284.
Xmniila piilorhynrha. the original of

the Guinea-fowl. i. 366.
Nun pigeon, i. 192 ; known to Aldro-

vandi, i. 252.
Nutmeg tree, ii. 286.

Oak. weepine, i. 435. ii. 29. 292; pyra-
midal, i. 435 : Hessian, i. 436 : late-
leaved, i. 436; variation in persis-
tency of leaves of, i. 436 : valueless
as timber at the Cape of Good Hope,

550

INDEX.

ii. 331 ; changes in, dependent on
age, i. 465 : gails of the, ii. 340.

Oats, wild, i. 377 ; in the Swiss lake-
dwellings, i. 3S5.

Orerlin, change of soil beneficial to
the potato, ii."l80.

Odart, Count, varieties of the vine, i.
333, ii. 335 ; bud-variation in the vine,
i. 451.

Odour and colour, correlation of, ii.
325.

(E'cidium, ii. 343.

(Enothera biennis, bud-variation in, i.
459.

Ogle, W., resemblance of twins, ii.
SOS.

Oil-gland, absence of, in fantail pi-
geons, i. 182, 197.

Oldpield, Mr., estimation of Euro-
pean clogs among the natives of Aus-
tralia, ii. 260.

Oleander, stock, affected by grafting
in the, i. 473.

Ollier, Dr., insertion of the perios-
teum of a dog beneath the skin of a
rabbit, ii. 443.

On&diwn, reproduction of, ii. 165, 166,
167. 200.

Onions, crossing of, ii. 115 : white, li-
able to the attacks of fungi and dis-
ease, ii. 276, 404.

Ophrys apifera, self-fertilisation of. ii.
115 : formation of pollen by a petal
in. ii. 469.

Opuntia leucotricha, ii. 335,

Orange, i. 403-406: crossing of. ii.
115 ; with the lemon, i. 470, ii. 437 :
naturalisation of, in Italy, ii. 371 ;
variation of. in North Italy, ii. 309 ;
peculiar variety of, ii. 393 ; Bizzaria,
i. 470; trifacial, ibid.

Orchids, reproduction of, i. 4S3, 484;
ii. 165-168.

Orford, Lord, crossing greyhounds
with the bulldog, i. 57.

Organisms, origin of, i. 25.

Organisation, advancement in, i. 10.'

Organs, rudimentary and aborted, ii.
379-383 ; multiplication of abnormal,
ii. 467.

Oriole, assumption of hen plumage
by a male in confinement, ii. 193.

Orkney islands, pigs of, i. 91 ; pigeons
of, i. 205.

Orthoptera, regeneration of hind
legs in the, ii. 354.

Orthoda munda, ii. 193.

Orton, R., on the effects of cross-
breeding on the female, i. 4S5 : on
the Manx cat, ii. S6 ; on mongrels
from the silk fowl, ii. 87.

Osborne, Dr., inherited mottling of
the iris, ii. 19.

Ospret, preying on Black-fowls, ii.
27S.

Osten-Sacken, Baron, on American
oak galls, ii. 340.

Osteological characters of piss. i. 86,
87, 92-96 ; of rabbits, i. 145-162 : of

pigeons, i. 200-207 ; of ducks, i. 341-
343.

Ostrich, diminished fertility of the,
in captivity, ii. 191

Osttaks, selection of dogs by the, ii.
250.

Otter, ii. 1S6.

"Otter" sheep of Massachusetts,!.
126.

Oude, feral humped cattle in, i. 102.

Ouistiti, breed in Europe, ii. 187.

Ovary, variation of, in Oucurbita mox-
chata, i. 432 ; development of, inde-
pendently of pollen, i. 4S3.

Ovis montana, i. 125.

Ovules and buds, identity of nature
of, u. 431.

Owen, Capt., on stiff-haired cats at
Mombas, i. 63.

Owen. Prof. R., pala?ontological evi-
dence as to the origin of dogs, i. 28 ;
on Bos lonrjlfroni, i. 104 ; on the skull
of the "Mata" cattle, i. 114; on fos-
sil remains of rabbits, i. 132 ; on the
significance of the brain, i. 156 ; on
the number of digits in the Ichthy-
opterygia, ii. 26 ; on metagenesis, ii.
439; theory of reproduction and
parthenogenesis, ii. 449.

Owl, eagle, breeding in captivity, ii.
188.

Owl pigeon, i. 184; African, figured,
i. 185 ; known in 1735. i. 255.

Oxalis, trimorphic species of, ii. 478.
rosea, ii. 164.

Oxley, Mr., on the nutmeg tree, ii.
286.

Oysters, differences in the shells of,
ii. 338.

Paca, sterility of the, in confinement,

ii. 187.
Pacific islands, pigs of the, i. 91.
Padua, earliest known flower garden

at, ii. 262.
Paduan fowl of Aldrovandi, i. 299.
PiMonia moutan, ii. 248.
Pjeony, tree, ancient cultivation of, in

China, ii. 248.
Pampas, feral cattle on the, i. 109.
Pandamis, ii. 309.

Pangenesis, hypothesis of, ii. *2S-483.
Panicum, seeds of, used as food. i. 373 ;

found in the Swiss lake-dwellings, i.

332.
Pansy, i. 442-445.
Pappus, abortion of the, in Cartha-

mus, ii. 3S1
Paget, on the Hungarian sheep dog, i.

Paget, inheritance of cancer, ii. 16 ;
hereditary elongation of hairs in the
eyebrow, ii. 17 ; period of inheritance
of cancer, ii. 102 ; on Hydra, ii. 353 ;
on the healing of wounds, ii. 354; on
the reparation of bones, ii. 354;
gowth of hair near inflamed surfaces
or fractures, ii. 356 ; on false mem-

INDEX.

PELARGONIUMS .

551

brancs, ii. 866 : compensatory de-
velopment of the kidney, ii. 361 ;
bronzed skin in disease of supra-re-
nal capsules, ii. 399 : unity of growth
and gemmation, ii. -130: indepen-
dence of the elements of the body, ii.
442 ; affinity of the tissues for special
organic substances, ii. 455.

Pallas, on the influence of domesti-
cation npon the sterility of inter-
crossed species, i. 40. 107. 386, ii. 187 ;
hypothesis that variability is wholly
due to crossing, i. 930, 44!t, ii. 302-
318 : on the origin of the dog. i. 28 :
variation in do^s. i. 4s ; crossing of
dog and jackal, i. 38; origin of do-
mestic cats, i. (id: origin of Angora
cat. i. 62 : on wild horses, i. 70, 79 ;
on Persian sheep, i. 120 ; on Siberian
fat-tailed sheep, ii. 337 ; on Chinese
sheep, ii. 379 ; on Crimean varieties
of the vine, i. 401 ; on a grape with
rudimentary seeds, ii. 3S0; on feral
musk ducks, ii. 63 ; sterility of Alpine
plants in gardens, ii. 199; selection
of white-failed yaks. ii. 249.

Paradoxurus, sterility of species of, in
captivity, ii. 1S4.

Paraguay, cats of, i. 03 ; cattle of, i.
113: horses of, ii. 199; dogs of, ii.
138 : black-skinned domestic fowl of,
i. 281.

Parallel, variation, ii. 417-423.

Paramos, woolly pigs of, i. 100.

Parasites, liability to attacks of, de-
pendent on colour, ii. 276.

Pariah dog, with crooked legs, i. 30 ;
rcsemblinz the Indian wolf. i. 38.

Pariset, inheritance of handwriting,
ii. 15.

Parker. \Y. K., number of vertebrae
in fowls, i. 393.

Parkinson. Mr., varieties of the hya-
cinth, i. 440.

Parkvns. Mansfield, on Cdtumba guir
n, l, i. 224.

Parmentier. differences in the nidifi-
cation of pigeons, i. 219 ; on white
pigeons, ii. 978.

Parrots, general sterility of, in con-
finement." ii. 189 ; alteration of plu-
mage of. ii. 337.

PAitsNir. reversion in. ii. 45 : influence
of selection on. ii. 243: experiments
on, ii. 335 : wild, enlargement of
roots of, by cultivation, i. 392.

Parthenogenesis, ii. 431. 437.

Partridge, sterility of, in captivity,
ii. 191.

Parturition, difficult, hereditary, ii.
17.

Parus major, ii. 279.

Pa8SiJlora, self-impotence in species of,
ii. 170-171 : contabescence of female
organs in, ii. 203.

Pamflorc . fertility of, when

grafted, ii. 339.

Pasture and climate, adaptation of
breeds of sheep to, i. 121. 122

Pastrana. Julia, peculiarities in the
hair and teeth of, ii. 394.

Patagonia, crania of pigs from, i. 99.

Patagonian rabbit, i. 133.

Paterson, R., on the Arrindy silk
moth. ii. 868.

Paul, W., on the hyacinth, i. 445 : va-
rieties of pelargoniums, i. 455: im-
provement of pelargoniums, ii. 261.

Pqvo crietatw and muticus, hybrids of,
i. 350.

Pavo nigripennfot, i. 350-352.

"Pavodotten-Taube." i. 175.

Peach, i. 406-114 : derived from the
almond, i. 407: stones of, figured, i.
401) : contrasted with almonds, :.
407 : double-flowering, i. 408, 414 : hy-
brids of, i. 408 ; persistency of races
of, i. 409: trees producing necta-
rines, i. 410-411 : variation in, i. 412-
414, ii. 309; bnd-variation in, i. 450:
pendulous, ii. 29 : variation by selec-
tion in, ii. 264 ; peculiar disease of
the, ii. 275 ; glands on the leaves of
the, ii. 280 : antiquity of the, ii. 371 :
increased hardiness of the. Ibid. :
varieties of, adapted for forcing, ii.
374; yellow-fleshed, liable to certain
diseases, ii. 404.

PEACH-Almond, i. 407.

Peafowl, origin of. i. 350: japanned
or black-shouldered, i. 350-357 ; fe-
ral, in Jamaica, i. 233 : comparative
fertility of, in wild and tame states,
ii. 140,*324; white, ii. 399.

Pears, i. 422 ; bud-variatfon in, i. 452 ;
reversion in seedling, ii. 45: inferi-
ority of, in Pliny's time, ii. 261 ;
winter nelis, attacked by aphides,
ii. 289 ; soft-barked varieties of, at-
tacked by wood-boring beetles, ii.
280; origination of good varieties
of, in woods, ii. 313 : Forelle, resist-
ance of, to frost, ii. 369.

Peas. i. 393-39S: origin of, i.393; va-
rieties of, 393-397, found in Swiss
lake-dwellings, i. 382. 385, 393-398;
fruit and seeds figured, i. 396 ; per-
sistency of varieties, i. 396 ; inter-
crossing of varieties, i. 397, 417, ii.
160: effect of crossing on the female
organs in, i. 477 ; double-tiowercd,
ii. 205 : maturity of, accelerated by
selection, ii. 243: varieties of, pro-
duced by selection, ii. 203: thin-
shelled, liable to the attacks of
birds, ii. 279 : reversion of. by the ter-
minal seed in the pod, ii. 417.

Peccart, breeding of the, in captivi-
ty, ii. 181.

Pedigrees of horses, cattle, grey-
hounds, game-cocks, and pigs, ii.
11.

Pegu, cats of, i. 64: horses of, i. 71.

Pelargoniums, multiple origin of, i.
438 : zones of, i. 440 : bud-variation
in. i. 434: variegation in. accompa-
nied by dwarfing, i. 461 : pelorism in,
ii. 203, 414; by reversion, ii. 78: ad-

D.T2

PELAI5G0NIUM.

IISTDEX.

vantage of change of soil to, ii. 180;
Improvement of, by selection, ii.
261 ; scorching of, ii. 277 ; numbers
of, raised from seed, ii. 284 ; effects
of conditions of life on, ii. 330;
stove-variety of, ii. 374 ; correlation
of contracted leaves and flowers in,
ii. 398.

Pelargonium fidqidxim, conditions of
fertility in, 'ii. 200.

" Pelones," a Columbian breed of cat-
tle, i. 113.

Peloric flowers, tendency of, to ac-
quire the normal form, ii. 00 ; fer-
tility or sterility of, ii. 203-204.

Peloric races of Gloxinia, tpeciosa and
'Antirrhinum majus, i. 439.

Pelorism, ii. 76-80, 415-416.

Pelvis, characters of, in rabbits, i.
154 ; in pigeons, i. 205 : in fowls, i.
323-324; in ducks, i. 343.

Pembroke cattle, i. 104.

Pendulous trees, i. 435, ii. 418; un-
certainy of transmission of, ii. 29-
30.

Penguin ducks, i. 338-341 ; hybrid of
the, with the Egyptian goose, i. 341.

Pennant, production of wolf-like curs
at Fochabers, i. 53; on the Duke of
Queensberry's wild cattle, i. 107.

Pennisetum, seeds of, used as food in
the Punjab, i. 372.

Pennitetum dittichiim, seeds of, used
as food in Central Africa, i. 372.

Percival, Mr., on inheritance in
horses, ii. 20 : on horn-like process-
es in horses, i. 67.

Perdix rubra, occasional fertility of, in
captivity, ii. 191.

Period of action of causes of varia-
bility, ii. 324.

Periosteum of a dog, producing bone
in a rabbit, ii. 443.

Periwinkle, sterility of, in England,
ii. 207.

Persia, estimation of pigeons in, i.
250 ; carrier pigeon of, i. 174-175 ;
tumbler pigeon of, i. 184-1S6 ; cats of,
i. 62-64 ; sheep of, i. 120.

Persica intermedia, i. 408.

Persistence of colour in horses i. 68 ;
of generic peculiarities, i. 79.

Peru, antiquity of maize in, i. 386 ;
peculiar potato from, i. 398; selec-
tion of wild animals practised by the
Incas of, ii. 251-252.

"Perucken-Taube," i. 190.

Petals, rudimentary, in cultivated
plants, ii. 380 ; producing pollen, ii.
469.

Petunias, multiple origin of, i. 438 ;
double-flowered, ii. 204.

"Pfauen-Taube," i. 181.

PhacocTuxrm Africarms, i. 98.

PhakinopHt, pelorism in, ii, 415.

Phalanges, deficiency of, ii. 94.

Phaps chalcoptera, ii. 419.

Phaseolm m uU&florus, ii. 372-388.

PJuueolus vulgaris, ii. 372.

Phasiannt pictvs, i. 332.

Phasiarms Amherttice, i. 332.

Pheasant, assumption of male plu-
mage by the hen, ii. 68 ; wildness of
hybrids of, with the common fowl,
ii. 61 ; prepotency of the, over the
fowl, ii. 88 ; diminished fecundity of
the, in captivity, ii. 190.

Pheasants, golden and Lady Am-
herst's, i. 332.

Pheasant-fowls, i. 296.

Philipeaux, regeneration of limbs in
the salamander, ii. 451.

Philippar, on the varieties of wheat,
i. 379.

Philippine Islands, named breeds of
game fowl in the, i. 231.

Phillips, Mr., on bud-variation in the
potato, i. 462.

Phlox, bud-variation by suckers in, i.
461.

Phthisis, affection of the fingers in,
ii. 399.

Pickering, Mr., on the grunting voice
of humped cattle, i. 102 ; occurrence
of the head of a fowl in an ancient
Egyptian procession, i. 279 ; seeding
of ordinarily seedless fruits, ii. 205 ;
extinction of ancient Egyptian breeds
of sheep and oxen, ii. 508 ; on an an-
cient Peruvian gourd, ii. 573.

Picotees, effect of conditions of life
on, ii. 337.

Pictet, A., oriental names of the pi-
geon, i. 249.

Pictet, Prof., origin of the dog, i. 28 ;
on fossil oxen, i. 104.

Piebalds, probably due to reversion,
ii. 51.

Pigeaux, hybrids of the hare and rab-
bit, ii. 124-187.

Pigeon a cravate, i. 184.

Pigeon Bagadais, i. 176, 177.

Pigeon coquille, i. 192-193.

Pigeon cygne, i. 177.

Pigeon heurte, i. 192.

Pigeon Patu Plongeur, i. 193.

Pigjeon Polonais, i. 179.

Pigeon Romain, i. 176, 178.

Pigeon tambour, i. 191.

Pigeon Turc, i. 173.

Pigeons, origin of, i. 163-166, 221-249 ;
classified table of breeds of, i. 169 ;
pouter, i. 170-172 ; carrier, i. 172-176 ;
runt, i. 170-179; barbs, i. 179-181;
fantail, i. 181-183; turbit and owl, i.
184; tumbler, i. 184-189: Indian
frill-back, i. 100 ; Jacobin, ibid. ;
trumpeter, i. 191 ; other breeds of, i.
191-194 ; differences of, equal to ge-
neric, i. 194-195: individual varia-
tions of, i. 195-198 ; variability of pe-
culiarities characteristic of breeds
in, i. 198-199 ; sexual variability in,
i. 199-200 ; osteology of, i. 200-207 ;
correlation of growth in, i. 207-210,
ii. 387 ; young of some varieties na-
ked when hatched, i. 210, ii. 399 ; ef-
fects of disuse in, i. 211-218; set-

INDEX.

o:>:)

tllng and roosting in trees, i. 222 :
floating in the Nile to drink, ibid. ;
Dovecot, i. 227-228; arguments for
unity of origin of, i. 230-249: feral
in various places, i. 233-234, ii. 17;
unity of coloration in,
reversion of mongrel, to coloration
of C. Rvia, i. 240-247 : history of the
cultivation of, i. 249-252; history of
the principal races of, i. 96
mode of production of races of, i.
272; reversion in, ii. 43,64; by
age, ii. 5 j ; produced by crossing in,
ii. 55, 64; prepotency of transmis-
sion of character in breeds of, ii. 86-
87 ; sexual differences in some vari-
eties of, ii. 95 : period of perfect plu-
mage in. ii. 98: effect of segregation
on, ii. 109 : p referent pairing of, with-
in the same breed, ii. 130 : fertility
of, increased by domestication, ii.
140, 190: effects of interbreeding and
necessity of crossing, ii. 155-157 ;
indifference of. to change of climate,
ii. 197; selection of, ii. 237, 241, 247;
among the Romans, ii. -j-lr, ■ uncon-
scious selection of, ii. 256. 259 : facili-
ty of selection of, ii. 283 ; white, liable
to the attacks of hawks, ii. 278 ;
effects of disuse of parts in. ii. 359 ;
fed upon meat, ii. 300 : effect of first
male upon the subsequent progeny of
the female, i. 486 : homology of the
leg and wing feathers in^ ii,
union of two outer toes in feather-
legged, ii. 3S9 ; correlation of beak,
limbs, tongue, and nostrils in, ii.
390; analogous variation in, ii. 419,
420; permanence of breeds of, ii.
572.
Pigs, of Swiss lake-dwellings, i. 88-
89 ; types of, derived from 5
fa and 8m indica, i. 86-87; Japanese
(Sus plidceps, Gray), figured, i. 90;
of Pacific islands, i. 91, ii. Ill : modi-
fications of skull in, i. 92, 94 : length
of intestines in. i. 95, ii. 305 : period
of gestation of, i. 95-90 : number of
vertebrae and ribs in, i. 96 : anomalous
forms, i. 90-98 ; development of tusks
and bristles in, i. 9S : striped young
of. i. 98-99 : reversion of feral to
wild type, i. 99-101, ii. 47, 64 : pro-
duction and changes of breeds of, by
intercrossing, i. 101 ; eft'ects produc-
ed by the first male upon the subse-
quent progeny of the female, i. 1-5:
two-legged race of, ii. 13; polydac-
tylism in. ii. 24: cross-reversion in,
ii. 49 : hybrid, wildness of, ii. 01 :
monstrous development of a probos-
cis in, ii. 70 : disappearance of tusks
in male under domestication, ii. 95 :
solid hoofed, ii. 572 : crosses of. ii.
117-120: mutual fertility of all vari-
eties of, ii. 13s; increased fertility
by domestication, ii. 139 ; ill -
of close interbreeding in, ii. 151-152;
influence of selection on, ii. 240;

prejudice against certain colours in,
ii. 254, 07 7. 405; unconscious selection
of, ii. 259 : black Virginian, ii. -' i
similarity of the best breeds of, ii.
891; change of form in. ii. 337: ef-
fects of disuse of parts in, ii. 860 ;
of, ii. 962; correlations in, ii.
394; white, buck-wheat injurious to,
ii. 406: tail of, grafted upon the
back. ii. 443 : extinction of the older
races of, ii. 508.

Pimenta. ii. 115.

Pimpernel, ii. 231.

Pdtb-apple, sterility and variability
of the. ii. 310.

Pink, Chinese, ii. 388.

Pinks, bud -variation in, i. 458; im-
provement of, ii. 202.

Firms pumilio, Mughus, and nana, va-
rieties of P. sylvesti :■■. i. 437.

Pin lis s>/f,:i stris, i. 437 ; ii. 373 ; hybrids
of with P. nigricans, ii. 161.

Piorey, on hereditary disease, ii. 1G,
100.

Pistacia lenUscus, ii. 331.

Pistils, rudimentary, in cultivated
plants, ii. 380.

Pistor, sterility of some mongrel pi-
geons, i. 235 : fertility of pigeons, ii.
140.

Pisum arvense and sativum, i. 393.

Pityriasis, versicolor, inheritance of,
ii. 101.

Plancfion, G., on a fossil vine. i. 400;
sterility of Jussi WAS in

France, ii. 208.

Plane tree, variety of the, i. 430.

Plantigrade, carnivora, general ste-
rility of the, in captivity, ii. 1S4.

Plants, progress of cultivation of,
i. 305-312: cultivated, their geogra-
phical derivation, i. 375 ; crossing of,
ii. 124-125, 158 ; comparative fertility
of wild and cultivated, ii. 141; self-
impotent, ii. 103 ; dimorphic, and tri-
morphic, ii. 102-173; sterility of, from
changed conditions, ii. 199-202 ; from
contabescence of anthers, ii. 202-
203 ; from monstrosities, ii. 203-204 ;
from doubling of the flowers, ii. 204-
205 ; from seedless fruit, ii. 205 ; from
excessive development of vegetative
organs, ii. 20G-20S ; influence of se-
lection on, ii. 241-244 ; variation by
selection, in useful parts of, ii. 262-
200; variability of, ii. 288; variabili-
ty of, induced by crossing, ii. 318;
direct action of change of climate
on. ii. 334 ; change of period of ve-
getation in, ii. 307 : varieties of, suit-
able to different climates, i;
correlated variability of, ii. 397-399 ;
antiquity of races of, ii. 572.

Plasticity, inheritance of, ii. 291.

Plateau, P., on the vision of amphi-
bious animals, ii. 369.

Platessajlesus, ii. 70.

Plato, notice of selection in breeding
dogs by, ii. 245.

554

INDEX.

PROPAGATION.

Plica polonica, ii. 333.

Pliny, on the crossing of shepherds1
dogs with the wolf, i. 37 ; on Pyr-
rhus' breed of cattle, ii. 245 ; on the
estimation of pigeons among the
Romans, i. 250 ; pears described by,
ii. 261.

Plum, i. 415-418; stones figured, i.
416; varieties of the, i. 415-417, ii.
264 ; bud-variation in the, i. 450 ; pe-
culiar disease of the, ii. 275 ; flower-
buds of, destroyed by bullfinches, ii.
230 ; purple-fruited, liable to certain
diseases, ii. 404.

Plumage, inherited peculiarities of, in
pigeons, i. 198 ; sexual peculiarities
of, in fowls, i. 304-309.

Plurality of races, Pouchet's views
on, i. 12.

Poa, seeds of, used as food, i. 372 ; spe-
cies of, propagated by bulblets, ii. 207.

Podolian cattle, i. 103.

Pointers, modification of, i. 58 :
crossed with the foxhound, ii. 120.

Pois sans parchemin, ii. 279.

Poiteau, origin of Cytisus Ad ami, i.
468 ; origin of cultivated varieties of
fruit-trees, ii. 313.

Polish fowl, i. 276, 307, 309-311, 317;
skull figured, i. 316 ; section of skull
figured, i. 318 ; development of pro-
tuberance of skull, i. 302; furcula
figured, i. 324.

Polish, or Himalayan rabbit, i. 136.

Pollen, ii. 435-437 ; action of, ii. 135 ;
injurious action of, in some orchids,
ii. 166-16S; resistance of, to injurious
treatment, ii. 200; prepotency of, ii.
227.

Pollock, Sir F., transmission of va-
riegated leaves in Ballota nigra, i.
460; on local tendency to variega-
tion, ii. 331.

Polyanthus, ii. 32.

Polydactylism, inheritance of, ii. 22-
26 ; significance of, ii. 26-27.

Polyplectron, i. 308.

Ponies, most frequent on islands and
mountains, i. 69 ; Javanese, i. 71.

Poole, Col., on striped Indian horses,
i. 77, 78 ; on the young of Asinus in-
dims, ii. 59.

Poplar, Lombardy, i. 435.

Poppig, on Cuban wild dogs, i. 41.

Poppy, found in the Swiss lake dwell-
ings, i. 382, 385 ; with the stamens
converted into pistils, i. 439 ; diffe-
rences of the, in different parts of
India, ii. 201 ; monstrous, fertility of,
ii. 203 ; black-seeded, antiquity of,
ii. 512.

Porcupine, breeding of, in captivity,
ii. 186.

Porcupine family, ii. 12, 98.

Parphyrio, breeding of a species of, in
captivity, ii. 192.

Portal, on a peculiar hereditary af-
fection of the eye, ii. 19.

Porto Santo, feral rabbits of, i. 141.

Potamocluerus penicillatus, ii. 184.

Potato, i. 39S-399 ; bud-variation by
tubers in the, i. 461-463 ; graft-hybrid
of, by union of half-tubers, i. 475 ;
individual self-impotence in the, ii.
169 ; sterility of, ii. 206 ; advantage
of change of soil to the, ii. 180 ; re-
lation of tubers and flowers in the,
ii. 412.

Potato, sweet, sterility of the, in
China, ii. 206 ; varieties of the, suit-
ed to different climates, ii. 371.

Pouchet, M., his views on plurality
of races, i. 12.

Pouter pigeons, i. 170-172; furcula
figured L 206 ; history of, i. 253.

Powis, Lord, experiments in crossing
humped and English cattle, i. 106, ii.
61.

Poynter, Mr., on a graft-hybrid rose,
i. 475.

Prairie wolf, i. 35.

Precocity of highly-improved breeds,
ii. 387.

Prepotency of pollen, ii. 227.

Prepotency of transmission of cha-
racter, ii. 84, 212 ; in the Austrian
emperors and some Roman families,
ii. 85 ; in cattle, ii. 85-86 ; in sheep,
ii. 86 ; in cats, ibid. ; in pigeons, ii.
86-87; in fowls, ii. 87 ; in plants, ibid.;
in a variety of the pumpkin, i. 431 ;
in the jackal over the dog, ii. 87 ; the
ass over the horse, ii. 88 ; in the phea-
sant over the fowl ibid. ; in the pen-
guin duck over the Egyptian goose,
tbkl. ; discussion of the phenomena
of, ii. 89-92.

Prescott, Mr., on the earliest known
European flower-garden, ii. 262.

Pressure, mechanical, a cause of
modification, ii. 413-414.

Prevost and Dumas on the employ-
ment of several spermatozoids to
fertilise one ovule, ii. 435.

Price, Mr., variations in the structure
of the feet in horses, i. 67.

Prichard, Dr., on polydactylism in
the negro, ii. 24 ; on the Lambert
family, ii. 98; on an albino negro, ii.
277 ; on Plica polonica, ii. 333.

Trimrose, ii. 32; double rendered
single by transplantation, ii. 204.

Pi imula, intercrossing of species of,
i. 405 ; contabescence in, ii. 203 ; hose
and hose, i. 439 ; with coloured caly-
ces, sterility of, ii. 203.

Primula sinensis, reciprocally dimor-
phic, ii. 163.

Primula Tens, ii. 32, 137, 222.

Primula vulgaris, ii. 32, 137.

Prince, Mr., on the intercrossing of
strawberrieSj i. 424.

Procyon, sterility of, in captivity, ii.
186.

Prolificacy, increased by domestica-
tion, ii. 212.

Propagation, rapidity of, favourable
to selection, ii. 283.

PROTOZOA.

INDEX.

a do

Protozoa, reproduction of the, ii.-loO.

Prunus arm* niaca, i. 414-115.

Prumw avium, i. 4is.

Prunus a rams, i. us. 451,

Prunus dorm stica, i. 415.

Primus insititia, i. 415-117.

Prunus spinoea, i. 115.

Prussia, wild horses in. i. 79.

PHttaeus erithacus, ii. 190.

Psittacus macoa, ii. 190.

Psophia. general sterility of, in capti-
vity, ii. 192.

Ptarmigan fowls, j. 277.

Pulex 1 :■ > a ■ ii. 382.

Pumpkins, i. 430.

Pino ponies of the Cordillera, i. 70.

Purser, Mr., on GyUsus Adami, i.
467.

Puset. Mr., preference of hares and
rabbits for common rye. ii. 281.

Putsche and Yertuch, varieties of the
potato, i. 398.

Puvis. effects of foreign pollen on
apples, i. 4S1 : supposed non-varia-
bility of monotypic genera, ii. 320.

Pyrrh'nlii vulgaris, ii. 280 : assumption
of the hen-plumage by the male, in
confinement, ii. 193.

Pyrrhus, his breed of cattle, ii. 245.

Pyrus, l'astigate Chinese species of, ii.
334.

Pyrus acerba, i. 419.

Fiji us aucuparia, ii. 279.

Pyrus communis, i. 422. 452.

Pyrus mains, i. 419. 452.

IJi//".< paradisiaca, i. 419.

Pyrus praeox, i. 419.

•

Quagga, effect of fecundation by, on
the subsequent progeny of a mare,
i. 484485.

Quatrefages, A. de, on the burrow-
ing of a bitch to litter, i. 41 ; selec-
tion in the silkworm, i. 302 : devel-
opment of the wings in the silkmoth,
i. SG6, ii. 402 ; on varieties of the mul-
berry, i. 360 ; special raising of eggs
of the silkmoth, ii. 239 ; on disease
of the silkworm, ii. 276 ; on mon-
strosities in insects, ii. 324, 468 ; on
the Anglo-Saxon race in America, ii.
334; on a change in the breeding
season of the Egyptian goose, ii.
366; fertilisation of the Teredo, ii.
435; tendency to similarity in the
be<t races, ii. 291 ; on his " tOurbUlon
vital," ii. 80: on the independent ex-
istence of the sexual elements, ii.
431.

Quercus eerris, i. 437.

Chi. rcusrdbwrsaA.pi duncuiata, hybrids
of. ii. 161.

Quince, pears grafted on the, ii. 312.

Rabbit?, domestic, their origin, i. 130-
133; of Mount Sinai and Algeria, i.
132: breeds of, i. 133-139: Himalay-
an,Chinese, Polish, or Russian, i. 186-

139. ii. 123 ; feral, i. 140-144 : of Jamai-
ca, i. 140: of the Falkland islands, i.
141 : of Porto Santo, i. 141-144. ii.
130, 337 ; osteological characters of,
i. 145-161 : discussion of modifications
in, i. 161-162; one-eared, transmis-
sion of peculiarity of, ii. 21 : rever-
sion in feral, ii. 47 ; in the Himalay-
an, ii. 56 ; crossing of white and
coloured Angora, ii. 117 : compara-
tive fertility of wild and tame, ii.
139: high-bred, often bad breeders,
ii. 151 ; selection of, ii. 247 ; white,
liable to destruction, ii. 278 ; effects
of disuse of parts in, ii. 359; skull
of, affected by drooping ears. ii.
363; length of intestines in. ii. 365;
correlation of ears and skull in, ii.
390-391; variations in skull of, ii.
421 ; periosteum of dog a producing
bone in, ii. 443.

Race-horse, origin of, i. 72.

Races, modification and formation of,
by crossing, ii. 120-125 : natural and
artificial, ii. 296 : Pouchet's views on
plurality of, i. 12; of pigeons, i. 252-
258.

Radishes, i. 392 : crossing of, ii. 115 ;
varieties ot. ii. 263.

Radcltffe, W. F., effect of climate
and soil on strawberries, i. 426 : con-
stitutional differences in roses, i.
441-442

Radlkofer, retrogressive metamor-
phosis in mosses and algae, ii. 433.

Raffles, Sir Stamford, on the cross-
ing of Javanese cattle with Bos son-
datcus, ii. 250.

Ram, goat-like, from the Cape of Good
Hope, ii. 85.

Ranchln. heredity of diseases, ii. 16.

Range of gallinaceous birds on the
Himalaya, i. 287.

Ranunculus jlcarid, ii. 208.

Ramunadus repens, ii. 205.

Rape, i. 392.

Rapltanus salivus, ii. 412.

Raspberry, yellow-fruited, ii. 278.

Rattlesnake, experiments with poi-
son of the, ii. 349.

Raven, stomach of, affected by vege-
table diet, ii. 364.

Rawson. A., self-impotence in hybrids
of Gladiolus, ii. 172-173.

Re, Le Compte, on the assumption of
a yellow colour by all varieties of
maize, i. 3S7.

Reaumur, effect of confinement upon
the cock, ii. 69 : fertility of fowls in
most climates, ii. 197.

Reed, Mr., atrophy of the limbs of
rabbits, consequent on the destruc-
tion of their nerves, ii. 368,

Regeneration of amputated parts in
man, ii. 24; in the human embryo,
ii. 25 ; in the lower vertebrata, in-
sects, and myriapoda, ii. 25.

Reindeer, individuals recognised by
the Laplanders, ii. 303.

556

INDEX.

ROBERTSON.

Regnier, early cultivation of the cab-
bage by the Celts, i. 390.

Reissek, experiments in crossing Cy-
tisus purpureas and laburnum, i. 468;
modification of a Thesium by CEci-
dium, ii. 343.

Relations, characters of, reproduced
in children, ii. 4S.

Rengger, occurrence of jaguars with
crooked legs in Paraguay, i. 30 ; na-
ked dogs of Paraguay, i. 37-45, ii.
117-128 ; feral dogs of La Plata, i. 41 ;
on the aguara, i. 40 ; cats 'of Para-
guay, i. 63, ii. 110-184 ; dogs of Para-
guay, ii. 110 ; feral pigs of Buenos
Ayres, i. 99 ; on the refusal of wild
animais to breed in captivity, ii. 183 ;
on Dicotyles labiatus, ii. 184: steri-
lity of plantigrade carnivora in cap-
tivity, ii. 186; on C'avia aperia, ii.
186 ; sterility of C'ebus azarce in cap-
tivity, ii. 188 ; abortions produced
by wild animals in captivity, ii. 194.

Reproduction, sexual and asexual,
contrasted, ii. 432 ; unity of forms
of, ii. 458 ; antagonism of, to growth,
ii. 460.

Reseda odorata, ii. 286.

Retinitis, pigmentary, in deaf-mutes,
ii. 395.

Reversion, ii. 41-42, 446^47, 474, 476-
480 ; in pigeons, ii. 43 ; in cattle, ii.
43 ; in sheep, ii. 43 ; in fowls, ii. 44 ; in
the heartsease, ii. 45 ; in vegetables,
ii. 45 ; in feral animals and plants,
ii. 46-48 ; to characters derived from
a previous cross in man, dogs, pi-
geons, pigs, and fowls, ii. 46-49 : in
hybrids, ii. 50; by bud-propagation
in plants, ii. 51-53 ; by age in fowls,
cattle, &c, ii. 53-54 ; caused by cross-
ing, ii. 54-68 ; explained by latent
characters, ii. 68-75 ; producing mon-
strosities, ii. 75-76 ; producing" pelor-
ic flowers, ii. 76-79 ; of feral pigs to
the wild type, i. 99-100 ; of supposed
feral rabbits to the wild type, i. 132,
140, 144; of pigeons, in coloration,
when crossed, i. 240-246; in fowls, i.
290-297 ; in the silkworm, i. 364 : in
the pansy, i. 444 ; in a pelargonium,
i. 454; in Chrysanthemums, i. 455;
of varieties of the China rose in St.
Domingo, i. 457 ; by buds in pinks
and carnations, i. 458 ; of laciniated
varieties of trees to the normal form,
i. 459 ; in variegated leaves of plants,
i. 461 ; in tulips, i. 463 ; of suckers
of the seedless barberry to the com-
mon form, i. 462 ; by buds in hybrids
of Tropceohmi, i. 470; in plants, i.
491 ; of crossed peloric snapdragons,
ii. 92; analogous variations due to,
ii. 418-423.
Retnier, selection practised by the

Celts, ii. 246.
Rhinoceros, breeding in captivity in

India, ii. 1S4.
Rhododendron, hybrid, ii. 320.

Rhododendron ciliatum, ii. 334.

Rhododendron Dallwm'uv, effect of pol-
len of R. NuttaUn upon, i. 480-4S1.

Rhubarb, not medicinal when grown
in England, ii. 331.

Ribes grossularia, I. 426-429, 451.

Ribes rubrum, i. 452.

Ribs, number and characters of, in
fowls, i. 322-323; characters of, in
ducks, i. 341-342.

Rice, Imperial, of China, ii. 248 ; In-
dian varieties of, ii. 309 ; variety of,
not requiringwater, ii. 367.

Richardson, H. D., on jaw-append-
ages in Irish pigs, i. 98 : manage-
ment of pigs in China, i. 89 ; occur-
rence of striped young in Westpha-
lian pigs, i. 99; on crossing pigs, ii.
120 ; on interbreeding pigs, ii. 151 ;
on selection in pigs, ii. 236.

Richardson, Sir John, observations
on the resemblance between North
American dogs and wolves, i. 34-35 ;
on the burrowing of wolves, i. 41 ;
on the broad feet of dogs, wolves,
and foxes in North America, i. 56 ;
on North American horses scraping
away the snow, i. 70.

Ricinus, annual in England, ii. 367.

Riedel, on the "Bagadotte" pigeon,
i. 175; on the Jacobin pigeon, iTl90;
fertility of hybrid pigeons, i. 335.

Rinderpest, ii. 452.

Risso, on varieties of the orange, i.
405, ii. 371, 398.

Rivers, Lord, on the selection of grey-
hounds, ii. 284.

Rivers, Mr., persistency of characters
in seedling potatdis, i. 399; on the
peach, i. 407-408 ; persistency of races
in the peach and nectarine, i. 409,410 ;
connexion between the peach and the
nectarine, i. 410 ; persistency of cha-
racter in seedling apricots, i. 415 ; ori-
gin of the plum, i. 415 ; seedling va-
rieties of the plum, i. 416 ; persisten-
cy of character in seedling plums, i.
418; bud-variation in the plum, i.
450; plum, attacked by bullfinches,
ii. 280 ; seedling apples with surface-
roots, i. 421 ; variety of the apple
found in a wood, ii. 314; on roses, i.
441-442 ; bud-variation in roses, i.
456-457 ; production of Provence
roses from seeds of the moss-rose,
i. 456 ; effect produced by grafting
on the stock in jessamine, i. 473 : in
the ash, i. 473 ; on grafted hazels, i.
474 ; hybridisation of a weeping
thorn, ii. 29; experiments with the
seed of the weeping elm and ash. ii.
30 ; variety of the cherry with curled
petals, ii. 281.
Riviere, reproduction of Oncidium

Vaveudix.hianiun, ii. 165.
Roberts, Mr., on inheritance in the

horse, ii. 20.
Robertson, Mr., on glandular-leaved
peaches, i. 413.

INDEX.

SALAMANDER.

Robixet, on the silkworm, i. 303, ii.
239.

'■•i. ii. 331.

Robson, Mr., deficiencies of half-bred
horses, ii. 21.

Robson, Mr., on the advantage of
change of soil to plants, ii. 180: pn
the growth of the verBena, ii. 330 ;
on broccoli, ii. 374.

Rock pigeon, measurements of the, i.
166-107; figured, i. 168.

Rodents, sterility of, iu captivity, ii.
186.

BodrigueHq, ii. 166,167.

Rodwell, J., poisoning of horses by
mildewed tares, ii. 405.

RoHnxrjND, feral humped cattle in, i.
102.

Rolle, F., on the history of the peach,
ii. 871.

Roller-pigeons, Dutch, i. 186.

Rolleston, Prof., incisor teeth affect-
ed in form in cases of pulmonary tu-
bercle, ii. 399.

Romans, estimation of pigeons by. i.
250 ; breeds of fowls possessed by, i.
881, 208.

Rooks, pied, ii. 99.

Bosa, cultivated species of, i. 441.

Bosa >h voniensis, graft-hyhrid produc-
ed by, on the white Banksian rose,
i. 475.

Rosa-indica and centifolia, fertile hy-
brids of, i. 441.

Horn f]nitoxi»siina, history of the cul-
ture of, i. 442.

Rosellini, on Egyptian dogs, i. 29.

Roses, i. 441-442; origin of, i. 438;
bud-variation in, i. 456-468 ; Scotch,
doubled by selection, ii. 243 ; con-
tinuous variation of, ii. 293 : effect
of seasonal conditions on, ii. 330 ;
noisette, ii. 371 ; galls of, ii. 342.

Rouennais rabbit, i. 133.

Roulin. on the dogs of Juan Fernan-
dez, i. 40 ; on South American cats,
i. 63; striped young pigs, i. 99: feral
pigs in South America", i. 100. i'l. 47 ;
on Columbian cattle, i. 113. ii. 348,
874 : effects of heat on the hides of
cattle in South America, i. 110 ; fleece
of sheep in the hot valleys of the
■ Cordilleras, i. 124 ; diminished fer-
tility of these sheep, ii. 197; on
black-boned South American fowls,
i. 312 ; variation of the guinea-fowl
in tropical America, i. 355 ; frequen-
cy of striped legs in mules, ii. 58 ;
geese in Bogota, ii. 197 ; sterility of
fowls introduced into Bolivia, ii.
197.

Rot, M., on a variety of Magnolia
grandiflora^ ii. 371.

Royle, Dr., Indian varieties of the
mulberry, i. 403 ; on Agave sivipa-
?•«, ii. 306 : variety of rice not requir-
ing irrigation, ii. 307: sheep from
the Cape in India, ii

Bubus, pollen of, ii. 333.

Rudimentary organs, i. 24, ii. 379-
383.

Kifz de Lavison, extinction of breeds

Of dogs in France, ii. 508.
Ruminants, general fertility of, in

captivity. Ii. 184.
RUMPLBSS fowls, i. 278.

Busts, i. 176-179: history of, i. 256;
Iowei jaws and skull figured, i.
202-203.

Russian or Himalayan rabbit, i. 136.

Rutimeyer, Prof, dogs of the Neo-
lithic period, i. 31 ; horses of Swiss
lake-dwellings, i. 00 ;• diversity of
early domesticated horses, i. 69 ; pigs
of the Swiss lake-dwellings, i. 85,
88-S9 ; on humped cattle, i. 103 ; pa-
rentage of European breeds of cat-
tle, i. 103, 104, ii. 510; on "Niata"
cattle, i. 113: sheep of the Swiss
lake-dwellings, i. 119, ii. 510 ; goats of
the Swiss lake dwellings, i. 127 : ab-
sence of fowls in the Swiss lake-
dwellings, i. 297 : on crossing cattle,
ii. 124; differences in the bones of
wild and domesticated animals, ii.
337 ; decrease in size of wild Euro-
pean animals, ii. 611.

Rye, wild, De Candolle's observations
on, i. 377; found in the Swiss lake-
dwellings, i. 385 ; common, preferred
by hares and rabbits, ii. 281 ; less
variable than other cultivated plants,
ii. 307. i

Sabine, Mr., on the cultivation of
Bona xjiiiioxi.isiiiia, i. 442: on the
cultivation of the dahlia, i. 444-445,
ii. 315; effect of foreign pollen on
the seed-vessel in Amaryllis vittala,
i. 480.

St. Ange, influence of the pelvis on
the shape of the kidneys in birds,
ii. 413.

St. Domingo, wild dogs of, i. 41 ; bud-
variation of dahlias in, i. 462.

St. Hilaike, Aug., milk furnished by
cows in South America, ii. 362 ;
husked form of maize, i. 386.

St. John, C, feral cats in Scotland, i.
64 : taming of wild ducks, i. 3:15.

St. Valery apple, singular structure
of the, i. 421 ; artificial fecundation
of the, i. 481.

St. Vitus' Dance, period of appear-
ance of, ii. O'.i.

Sageret, orisin and varieties of the
cherry, i. 417-419 ; origin of varieties
of the apple, i. 422;" incapacity of
the cucumber for crossing with oth-
er species, i. 433; varieties of the
melon, ibid. : supposed twin-mongrel
melon, i. 469 ; crossing melons, ii.
135, 160; on gourds, ii. 135: effects
of selection in enlarging fruit ii.
202 : on the tendency to depart from
type. ii. 393; variation of plants in
particular soiK ii. 335.

Salamander, experiments on the, ii.

558

SAJLAMANDRA.

INDEX.

354, 409 ; regeneration of lost parts
in the, ii. 25, 450, 461.

Salamandra cristata, polydactylism
in, ii. 24.

Salisbury, Mr., on the production
of nectarines by peach-trees, i. 410 ;
on the dahlia, i. 445.

/Sali.r, intercrossing of species of, i.
405.

Salix humilis, galls of, ii. 340, 341.

Salle, feral guinea-fowl in St. Domin-
go, i. 355.

Salmon, early breeding of male, ii. 460.

Salter, Mr.f on bud-variation in pe-
largoniums, i. 434; in the Chrysan-
themum, i. 455 ; transmission of va-
riegated leaves by seed, i. 460 ; bud-
variation by suckers in Phlox, i.
461 ; application of selection to bud-
varieties of plants, i. 493 ; accumu-
lative effetJt of changed conditions
of life, ii. 316 ; on the variegation of
strawberry leaves, ii. 331.

Salter, S. J., hybrids of Gattm Son-
neratil and the common fowl, i. 284 ;
ii. 61 ; crossing of races or species
of rats, ii. 111.

Samesreuther, on inheritance in cat-
tle, ii. 20.

Sandfofd. See Dawkins.

Sap, ascent of the, ii. 357.

Saponaria calabrica, ii. 31.

Sardinia, ponies of, i. 69.

Sars, on the development of the hy-
droida, ii. 441.

Satiation of the stigma, i. 483-484.

Satwnia pi/ri, sterility of, in confine-
ment, ii. 193.

Saul, on the management of prize
gooseberries i. 429.

Sauvignt, varieties of the goldfish, i.
357.

Savages, their indiscriminate use of
plants as food, i. 371-374; fondness
of, for taming animals, ii. 196.

Savi, effect of foreign pollen on maize,
i. 480.

Saasifraga geum, ii. 203.

Sayzid Mohammed Musari, on car-
rier pigeons, i. 175 ; on a pigeon
which utters the sound " Yahu," i.
192.

Scanderoons (pigeons), i. 176, 177.

Scania, remains of Bos frontosus
found in, i. 104.'

Scapula, characters of, in rabbits, i.
154 ; in fowls, i. 324 ; in pigeons, i.
205; alteration of, by disuse in pi-
geons, i. 215-216.

Scarlet fever, ii. 333.

Schaaffhausen on the horses repre-
sented in Greek statues, ii. 258.

Schacht, H., on adventitious buds,
ii. 459.

Schleiden, excess of nourishment a
cause of variability, ii. 310.

Schomburgk, Sir R., on the dogs of
the Indians of Guiana, i. 32, 36,
ii. 250 ; on the musk duck, i. 223 ;

bud-variation in the Banana, i. 452-
453; reversion of varieties of the
China rose in St. Domingo, i. 457 ;
sterility of tame parrots in Guiana,
ii. 190; on Dendrocygna rhJuuta, ii.
192 ; selection of fowls in Guiana, ii.
254.

Schreibers*, on Proteus, ii. 358.

Sciuroptertis vohicdla, ii. 187.

Scwrus palmarum and ciiierea, ii. 187.

Sclater, P. L., on Asians tceniopus,
i. 81, ii. 57; on Acinus indicus, ii.
58 ; striped character of young wild
pigs, i. 91; osteology of Gull "inula
nesioiis, i. 346 ; on the black-shoul-
dered peacock, i. 350 ; on the breed-
ing of birds in captivity, ii. 192.

Schmerling, Dr., varieties of the dog
found in a cave, i. 31.

Scotch fir, local variation of, i. 437.

Scotch kail and cabbage, cross be-
tween , ii. 123.

Scott, 0 ohn, irregularities in the sex of
the flowers of Maize, i. 387 ; bud-va-
riation in Imatophylliim miniatum,i.
463 ; crossing of species of Yerbas-
cum, ii. 133-134; experiments on
crossing Primulce, ii. 136 ; reproduc-
tion of orchids, ii. 165 ; fertility of
Oncidium divaricatum, ii. 200; ac-
climatisation of the sweet pea in In-
dia, ii. 374 ; number of seeds in Ac-
ropera and Gongora, ii. 453.

Scott, Sir W., former range of wild
cattle in Britain, i. 109.

Scrope, on the Scotch decrhound, ii.
95, 150.

Sebright, Sir John, effects of close
interbreeding in dogs, ii. 151 ; care
taken by, in selection of fowls, ii.
239.

Secale cereale, ii. 307.

Sedgwick, W., effects of crossing on
the female, i. 485; on the"Porcu-
pineman," ii. 12 ; on hereditary dis-
eases, ii. 16 ; hereditary affections of
the eye, ii. 18, 101-102 ; inheritance
of polydactylism and anomalies of
the extremities, ii. 23-24; morbid
uniformity in the same family, ii. 28 ;
on deaf mutes, ii. 34; inheritance of
injury to the eye, ii. 36 ; atavism in
diseases and anomalies of structure,
ii. 48 ; non-reversion to night-blind-
ness, ii. 51 ; sexual limitation of the
transmission of peculiarities in man,
ii. 93-94 ; on the effects ot hard-drink-
ing, ii. 349 ; inherited baldness with
deficiency of teeth, ii. 393; occurrence
of a molar tooth in place of an in-
cisor, ii. 468 ; diseases occurring in
alternate generations, ii. 480.

Sedillot, on the removal of portions
of bone, ii. 356.

Seeds, early selection of, ii. 247 ; rudi-
mentary, in grapes, ii. 380 : relative
position of, in the capsule, ii. 414.

Seeds and buds, close analogies of, i.
493.

INDEX.

559

Seemann, B., crossing of the wolf and
Esquimaux dog, i. 35.

Selby, P. J., on the bud-destroying
habits of the bullfinch, ii. 880,

Selection, ii. 333-301 : methodical, i.
260, ii. 335-255; by the ancients and
semi-civilized people, ii. 844-255; of
trifling characters, ii. 353-255; un-
conscious, i. 261, 264, ii. 312, 356-262 ;
effects of, shown by differences in
most valued parts, ii. 362-267: pro-
duced by accumulation of variabili-
ty, ii. 267-270: natural, as affecting
domestic productions, ii. 235-229, 871-
282 : as the origin of species, genera,
and other groups, ii. 513-513; cir-
cumstances favourable to, ii. 232-289 ;
tendency of, towards extremes, ii.
290-292 ; possible limit of, ii. 292 : in-
fluence of time on, ii. 293-293 : sum-
mary of subject, ii. 298-301 ; effects
of, in modifying breeds of cattle, i.
117, 118; in preserving the purity of
breeds of sheep, i. 126 ; in produc-
ing varieties of pigeons,!. 200-266;
in breeding fowls, i. 281-282; in the
goose, i. 319; in the canary, i. 355-
336 ; in the gold-fish, i. 357 ; in the
silkworm, i. 361-362; contrasted in
cabbages and cereals, i. 389; in the
white mulberry, i. 402-403 ; on goose-
berries, i. 429 : applied to wheat, i.
882-383; exemplified in carrots, &c,
i. 393 ; in the potato, i. 303 : in the
meloh. i. 433: in flowering plants, i.
439 ; in the hyacinth, i. 446 : applied
to bud-varieties of plants, i. 493 ; il-
lustrations of. ii. 503-512.

Selection, sexual, ii. 96.

Self-impotence in plants, ii. 163-173;
in individual plants, ii. 16S-171 ; of
hybrids, ii. 213.

Selwtn, Mr., on the Din<ro, i. 39.

Skltb-Longchakps, on hybrid ducks,
i. 233. ii. 62. 192 : hybrid of the hook-
billed duck and Egyptian goose, i.
341.

Seringe, on the St.Valery apple, i. 421.

Serpent Melon, i. 433.

Serres, Olivier de, wild poultry in
Guiana, i. 228.

Sesamum, white-seeded, antiquity of
the. ii. 513.

8 tana, found in the Swiss lake-dwell-
ing, i. 332.

Setters, defeneration of, in India, i.
53 ; Youatt's remarks on, i. 57.

Sex, secondary characters of, latent,
ii. 68-69 ; of parents, influence of, on
hybrids, ii. 322.

Sexual characters, sometimes lost in
domestication, ii. 95.

Sexual limitation of characters, ii.
9246.

Sexual peculiarities, induced by do-
mestication in sheep, i. 121 ; in fowls,
i. 304-311 : transfer of, i. 308-311.

Sexual variability in pigeons, i. 199-
200.

Sexual selection, ii. 96.

Shaddock, i. 403.

Shau.ek, Mr., on the moss-rose, i.
456.

Shan&hai fowls, i. 275.

Shanghai sheep, their fecundity, i.
128.

Shan ponies, striped, i. 77.

Sheep, disputed origin of, i. 119 ;
early domestication of, i. 119; larger
tailed, i. 120, 124, ii. 337; variations
in horns, mammffl and other charac-
ters of, i. 120, 121 ; sexual characters
of, induced by domestication, i. 121 ;
adaptation of, to climate and pas-
ture, i. 121, 122: periods of gesta-
tion of, i. 123 ; effect of heat on the
fleece of, i. 121, 125, ii. 336; effect
of selection on, i. 126; •'anion" or
"otter" breeds of, i. 126, ii. 117;
" Manchamp-merino," i. 127; cross
of German and merino, ii. 112-113 ;
black, of the Tarentino, ii. 275 : Ka-
rakool, ii. 336 ; Jaffna, with callosi-
ties on the knees, ii. 363 ; Chinese,
ii. 370 ; Danish, of the bronze period,
ii. 510 ; polydactylism in, ii. 24 ; oc-
casional production of horns in horn-
less breeds of, ii. 43 ; reversion of
colour in, ii. 44 ; influence of male,
on offspring, ii. 89 ; sexual differ-
ences in, ii. 95 : influence of cross-
ing or segregation on, ii. 109, 120-
121, 129 ; interbreeding of, ii. 149 ;
effect of nourishment on the fer-
tility of, ii. 140: diminished fertility
of, under certain conditions, ii. 197 ;
unconscious selection of, ii. 258 ;
natural selection in breeds of, ii.
272, 275 : reduction of bones in, ii.
293 ; individual differences of, ii.
303 ; local changes in the fleece of,
in England, ii. 336 ; partial degener-
ation of, in Australia, ii. 336 ; with
numerous horns, i. 120 ; correlation
of horns and fleece in, ii. 292 ; feed-
ing on flesh, ii. 365 ; acclimatisation
of, ii. 368 ; mountain, resistance of,
to severe weather, ii. 376 ; white,
poisoned by Hypericum crispimh. ii.
405.

Sheep dogs resembling wolves, i. 37.

Shells, sinistral and dextral, ii. 71.

Sheriff, Mr., new varieties of wheat,
i. 379, 3,82 : on crossing wheat, ii.
131 ; continuous variation of wheat,
ii. 292.

SlAH, cats of. i. 64 ; horses of, i. 71.

Shirlet, E. P., on the fallow-deer, ii.
129, 151.

Short, D., hybrids of the domestic
cat and Ft'i* omnia, i. 61.

Siberia, northern range of wild horses
in. i. 70.

Sichel, J., on the deafness of white
cats with blue eyes, ii. 396.

Sidnet, S., on the pedigrees of pigs,
ii. 12; on cross-reversion in pigs, ii.
19 ; period of gestation in the pig, i.

560

IXDEX.

95-96 ; production of breeds of pises by
intercrossing, i. 101, ii. 120 ; fertility
of the pis, ii. 140 ; effects of inter-
breeding on pigs, ii. 1.51-152 ; on the
colours "of pigs, ii. 254, 2TT.

Siebold, on the sweet potato, ii. 372.

Siebold. von Carl, on parthenogene-
sis, ii. 436.

. contabeseenee in. ii. 202.

£ilk-fowls. i. 278. ii. 87.

Silk-moth. Arrindy, ii. 358, 378 ; Tar-
roo, ii. 193.

Silk-moths, i. 361-307 : domesticated
species of, i. 362 : history of. i
causes of modification in. i. 31
differences presented by. i. 363-364 ;
crossing of, ii. 124 ; disease in, ii.
276 ; effects of disuse of parts in. ii.
360 : selection practised with. ii.
239, 241 ; variation of, ii. 286 ; par-
thenogenesis in, ii. 436.

Silkworms, variations of, i. 363-364:
yielding white cocoons, less liable
to disease, ii. 405.

Silver-Grey rabbit, i. 136. 140, 150.

Simonds, J. B.. period of maturity in
various breeds of" cattle, i. Ill ; dif-
ferences in the periods of dentition
in sheep, i. 121 : on the teeth in cat-
tle, sheep, <fcc., ii. 387 : on the breed-
ing of superior rams, ii. 238.

Simon, on the raising of eggs of the
silk-moth in China, ii. 239.

Simpson, Sir J., regenerative power
of the human embryo, ii. 25.

<i, breeding in the branchiferous
stage, ii. 460.

Siskin, breeding in captivity, ii. 189.
. resemblance of the, to
Niata cattle, i. 113-114.

Size, difference of, an obstacle to
crossing, ii. 128.

Sktn, and its appendages, homolo-
gous, ii. 391 ; hereditary affections of
the. ii. 101.

Skirving. 4!. S.. on pigeons settling
on trees in Egypt, i. 222.

Skull, characters of the, in breeds
of dozs. i. 49 : in breeds of pigs, i.
92; in rabbits, i. 145-151. 160; in
breeds of pigeons, i. 202-204 : in
breeds of fowls, i. 314-321 : in ducks,
i. 341.

Skull and horns, correlation of the,
ii. 401.

Skyxaf.k, ii. 1S9.

Sleehan, on the Cheetah, ii. 184.

Sloe, i. 415.

Small-pox. ii. 452.

Smiter (pigeon), i. 193.

Smith, Sir" A., on Caffrarian cattle, i.
112 : on the use of numerous plants
as food in South Africa, i. 371.

Smith, Colonel Hamilton, on the odour
of the jackal, i. 44 : on the origin of
the dog. i. 28; wild dogs in St. Do-
mingo, i. 41 ; on the Thibet mastiff
and"the alco, i. 43 : development of
the fifth toe in the hind feet of mas-

tiffs, i. 50 : differences in the skull
of "dogs, i. 49 : history of the point-
er, i. 48 ; on the ears of the dog. ii.
363 : on the breeds of horses, i. 66 ;
origin of the horse, i. 68 ; dappling
of horses, i. 73 : striped horses in
Spain, i. 76-77 : original colour of
the horse, i, 79 : on horses scraping
away snow. i. 70: on Asinua hemv-
. ii. 59 : feral pigs of Jamaica, i.
99-100.

Smith. Sir J. E., production of nec-
tarines and peaches by the same
tree. i. 410 : on Viola amoena. i. 443;
sterility of Vinca minor in England,
ii. 207.

Smith. .T.. development of the ovary
in Bt ■". by irritation of

the stigma, i. 483-184.

Smith, N. H.. influence of the bull
•• Favourite" on the breed of Short-
horn cattle, ii. 85.

Smith, W.. on the intercrossing of
strawberries, i. 424.

Snake-rat, ii. 111.

Snakes, form of the viscera in, ii. 413.

Snapdragon, bud-variation in, i. 458 ;
non-inheritance of colour in, ii. 32 :
peloric crossed with the normal
form, ii. 90, 118 ; a symmetrical va-
riation of the, ii. 388.

Soil, adaptation of plums to, i. 417 ;
influence of, on the zones of pelar-
goniums, i. 4-10 : on roses, i. 441 : on
the variegation of leaves, i. 460 : ad-
vantages of change of, ii. 179-181.

Soil and climate, effects of, on straw-
berries, i. 425.

Solatium, non-intercrossing of species
of, ii. 115.

rosam, i. 398-399.

Solid-hoofed pigs, i. 96.

Solomon, his stud of horses, i. 72.

Somerville, Lord, on the fleece of
Merino sheep, i. 125 : on crossing
sheep, ii. 149 : on selection of sheep,
ii. 236 : diminished fertility of Meri-
no sheep brought from Spain, ii.
197.

Soott fowls, i. 278. 310.

Soto, Ferdinand de, on the cultiva-
tion of native plants in Florida, i.
376.

ium, i. 417.

Spain, hawthorn monogynous in, i.
438.

Spallanzani, on feral rabbits in Li-
pari. i. 142 ; experiments on sala-
manders, ii. 26, 354, 461 ; experi-
ments- in feeding a pigeon with
meat, ii. 360.

Spaniels, in India, i. 53 : King
Charles's, i. 57: degeneration of,
caused by interbreeding, ii. 150.

Spanish fowls, i. 275, 304, 306: fig-
ured, i. 274 : early development of
sexual characters in, i. 302-304 ; fur-
cula of, figured, i. 324.

Species, difficulty of distinguishing

INDEX.

SUCCESSION.

501

from varieties, i. 15; conversion of
varieties into, i. 16; origin of, by
natural selection, 11. 496-497 ; bj mu-
tual sterility of varieties, ii. 225-229.

Spencer. Lord, on selection in breed-
ing, ii. 286.

Spencer, Herbert, on the " survival
of the fittest.'" i. IT : increase of fer-
tility by domestication, ii. 189; on
life, ii. 181, 916; changes produced
by external conditions, ii. 889; ef-
fects of use on organs, ii. 866, 867;
ascent of the sap in trees, ii. :S57 ;
correlation exemplified in the Irish
elk. ii. 401-402; on "physiological
units," ii. 449 : antagonism of growth
and reproduction, ii. 4(10 ; formation
of ducts in plants, ii. 361.

Spermatophores of the cephalopoda,
ii. 459.

Sfermatozoids, ii. 436-436; apparent
independence of. in insects, ii. 459.

Sphingid-e, sterility of, in captivity,
ii. 193.

Spixola, on the injurious effect pro-
duced by flowering buckwheat on
■white pigs, ii. 405.

Spitz dog, i. 45.

Spooner. W. C, cross-breeding of
sheep, i. 126, ii. 121, 149 ; on the ef-
fects of crossing, ii. 199; on crossing
cattle, ii. 148 ; individual sterility, ii.
1%.

Spores, reproduction of abnormal
forms by, i. 460.

Sports, i. 448 : in pisreons, i. 259.

Spot pigeon, i. 192, 252.

Sprengel, C. K., on dichogamous
plants, ii. 114 : on the hollyhock, ii.
135 : ou the functions of flowers, ii.
214.

Sproule. Mr., inheritance of cleft-pa-
late and hare-lip. ii. 36.

Spttrs, of fowls, i. 30S ; development
of. in hens, ii. 382.

Squashes, i. 430.

Squinting, hereditary, ii. 18.

Squirrels, generally sterile in captiv-
ity, ii. 1ST.

Squirrels, flyiftg, breeding in con-
finement, ii. 1ST.

" Staardalsige Taube," i. 19S.

Stag, one-horned, supposed heredity
of character in. ii. 22; degeneracy of,
in the Highlands, ii. 252."

STAMENS, occurrence of rudimentary,
ii. 380; conversion of, into pistils, i.
439: into petals, ii. 469.

Staphylea, ii. 205.

Stebnstbup, Prof., on the dog of the
Danish Middens, i. 31 : on the obli-
quity of flounders, ii. TO.

Steinan, J., on hereditary diseases, ii.
16, 101.

Sterilitt, in dogs, consequent on
close confinement, i. IT: compara-
tive, of crosses, ii. 129-130: from
changed conditions of life, ii. 183-901 ;
occurring in the descendants of wild

animals bred in captivity, ii. 196;
individual, ii. 19S; resulting from
propagation by buds, cuttings, bulbs,
Ssc., ii. 206; in hybrids, ii.' 317-23 I,
462, 490-491; in specific hybrids of
pigeons, i. 236 ; as connected with
natural selection, ii. 296-929.

Sternum, characters of the, in rab-
bits, i. 154; in pigeons, i. 906, 214-
215; in fowls, i. 324, 880; effects of
disuse on the. i. 914-915, 880.

Stephens. J. F.. on the habits of the
Bombycid;e. i. 365.

Stewart, H., on hereditary disease,
ii. 101.

Stigma, variation of the. in cultivated
Cucurbitacese, i. 439 : satiation of
the. i. 483-484.

Stocks, bud-variation in. i. 458: effect
of crossing upon the colour of the
seed of. i. 3784179; true by seed, ii.
31: crosses of, ii. 117: varieties of,
produced by selection, ii. 966; rever-
sion by the upper seeds in the pods
of, ii. 417.

Stockholm, fruit trees of, ii. 369.

Stokes. Prof., calculation of the
chanco of transmission of abuormal
peculiarities in man, ii. 14.

Stolons, variations in the production
of, by strawberries, i. 495.

Stomach, structure of the, affected by
food, ii. 364.

Stone in the bladder, hereditary, ii.
17, 101.

Strawberries, i. 499-496; remark-
able varieties of, i. 4-24-4-.'5 : hautbois,
dioecious, i. 135 : selection in. ii. 943 :
mildew of. ii. 2T6 : probable further
modification of. ii. 203: variegated,
effects of soil on. ii. 331.

Strickland, A., on the domestication
of Anserferus, i. 34T: on the colour
of the biil and legs in geese, i. 348.

8tricta nas, i. 224.

Stripes on young of wild swine, i. 99 ;
of domestic pigs of Turkey. West-
phalia, and the Zambesi, i. 99: of fe-
ral swine of Jamaica and New Gran-
ada, i. 99; of fruit and flowers, i.
480, ii. 52 fin horses, i. T4-T9: in the
ass. i. S2-S3 : production of, by cross-
ing species of Eqnidae, ii. 58-59.
graUai in. ii. 364.
pas& r'uKi, ii. 189.

" Strupp-Taube," i. 192.

Strutiiers. Iffr., osteology of the feet
in solid-hoofed piss, i. 9T ; on poly-
dactylism. ii. 23-24.

Sturm, prepotency of transmission of
characters in sheep and cattle, ii. 86:
absorption of the minority in crossed
races, ii. Ill: correlation of twisted
horns and curled wool in sheep, ii.
893.

Bub-species, wild, of Columba livia
and other pigeons, i. 249.

• ion. ideological, of organisms,
i. 23.

562

INDEX.

TEGETMEIER.

Suckers, bud-variation by, i. 461.
Sugar cane, sterility of, in various

countries, ii. 208 ; white, liability of,

to disease, ii. 276, 404.
Suicide, hereditary tendency to, ii. 16,

100.
Suliyan, Admiral, on the horses of

the Falkland Islands, i. 70 : wild pigs

of the Falkland Islands, i. 90 ; feral

cattle of the Falkland Islands, i. 110,

ii. 12S ; feral rabbits of the Falkland

Islands, i. 141.
Sultan fowl, i. 277, 30S.
Sits indica, i. 86, 87-91, ii. 133.
Susplidceps, i. 90 (figured).
Sus scrofa, i. 86, 87, ii. 138.
Sus scrofa palustris, i. 88.
Sits vittatus, i. S3.
Swallows, a breed of pigeons, i. 192-

193.
Swatne, Mr., on artificial crossing of

varieties of the pea, i. 477.
Sweet Peas, ii. 115 : crosses of, ii. US ;

varieties of, coming true by seed, ii.

32 ; acclimatisation of, in India, ii.

374.
Sweet William, bud-variation in, i.

458.
Swinhoe, R., on Chinese pigeons, i.

251; on striped Chinese horses, i.

77.
Switzerland, ancient dogs of, i. 31 ;

pigs of, in the Neolithic period, i. 88-

89 ; goats of, i. 127.
Sycamore, pale-leaved variety of the,

ii. 397.
Sykes, Colonel, on a Pariah dog with

crooked legs, i. 30 ; on small Indian

asses, i. 82: on GaHus Sonnera/ii, i.

283 ; on the voice of the Indian Kulm

cock, i. 313 ; fertility of the fowl in

most climates, ii. 197.
Symmetry, hereditary departures

from, ii. 21.
Symphytum, variegated, i. 461.
Syphilis, hereditary, ii. 399.
Syria, asses of, i. 81.
Syringa persica, chinensis, and vulga-
ris,^. 200.

Tacitus, on the care taken by the Celts
in breeding animals, ii. 245.

Tagetes signata, dwarf variety of, ii.
31.

Tahiti, varieties of cultivated plants
in, ii. 309.

Tail, occasional development of, in
man, ii. 76 ; never curled in wild ani-
mals, ii. 363; rudimentary in Chi-
nese sheep, ii. 379.

Tail-feathers, numbers of, in breeds
of pigeons, i. 195-196 ; peculiarities
of, in cocks, i. 308 ; variability of, in
fowls, i. 312 ; curled, in A//as boschas,
and tamed drakes, i. 337.

Talent, hereditary, ii. 16.

Tankerveele, Earl of, on Ckillingham
cattle, i. 84, ii. 143.

Tanner, Prof., effects of disuse of
parts in cattle, ii. 361.

Tapir, sterility of the, in captivity, ii.
1S4.

Targione-Tozzetti, on cultivated
plants, i. 369 ; on the vine, i. 400 : va-
rieties of the peach, i. 413 ; origin
and varieties of the plum, i. 415 ; ori-
gin of the cherry, i. 418 ; origin of
roses, i. 441.

Tarsus, variability of the, in fowls, i.
313 ; reproduction of the, in a thrush,
ii. 26.

Tartars, their preference for spiral-
horned sheep, ii. 253.

Tavernier, abundance of pigeons in
Persia, i. 250.

Tuxuf baccata, ii. 29.

Teebay, Mr., reversion in fowls, ii. 53.

Teeth, number and position of, in
dogs, i. 49 ; deficiency of, in naked
Turkish dogs, i. 49 ; period of ap-
pearance of, in breeds of dogs, i. 50 ;
precocity of, in highly bred animals,
ii. 387 : correlation of, with hair. ii.
393 ; double row of, with redundant
hair, in Julia Pastrana, ii. 394 ; affect-
ed in form by hereditary syphilis
and by pulmonary tubercle, ii. 399 ;
fusion of, ii. 409 ; developed on the
palate, ii. 468.

Tegetmeier, Mr., on a cat with mon-
strous teeth, i. 65 ; on a swift-like
pigeon, i. 194 : naked young of some
pigeons, i. 210; fertility of hybrid
pigeons, i. 235 ; on white pigeons, ii.
278 ; reversion in crossed breeds of
fowls, i. 290-295 ; chicks of the white
silk-fowl, i. 301 ; development of the
cranial protuberance in Polish fowls,
i. 302; on the skull in the Polish
fowl, i. 310, 317 ; on the intelligence
of Polish fowls, i. 319 ; correlation
of the cranial protuberance and crest
in Polish fowls, i. 332 ; development
of the web in the feet of Polish
fowls, i. 313 : early development of
several peculiarities in Spanish
cocks, i. 302-303; on the comb in
Spanish fowls, i. 306 ; on the Spanish
fowl, ii. 368 ; varieties of game-fowls,
i. 304; pedigrees of game-fowls, ii.
12; assumption of female plumage
by a game cock, i. 305-306 ; natural
selection in the game cock, ii. 272 ;
pugnacity of game hens, i. 309 ;
length of the middle toe in Cochin
fowls, i. 313 ; origin of the Sebright
bantam, ii. 72; differences in the
size of fowls, i. 311 ; effect of cross-
ing in fowls, i. 311, ii. 121 ; effects of
interbreeding in fowls, ii. 154-155 ;
incubation by mongrels of non-sit-
ting races of fowls, ii. 60 ; inverse
correlation of crest and comb in
fowls, i. 331 : occurrence of pencil-
led feathers in fowls, ii. 56 ; on a va-
riety of the goose from Sebastopol,
i. 348 ; on the fertility of the peahen,

TEMMINCK.

INDEX.

563

ii. 140; on the intercrossing of bees,
ii. 157.

Temminck, origin of domestic cats, i.
60; origin of domestic pigeons, i.
2-Jl : on Oolwnba guinea, 1.294 ; on
Columba !< ueocephala, ibid. : assert-
ed reluctance of some breeds of pi-
geons to cross, i. 235 ; sterility of hy-
brid turtle-doves, i. 336; variations
of Qaltua imiikira. i. 386 ; on a buff-
coloured breed of Turkeys, i. 354 ;
number of eggs laid by the peahen ;
ii. 140 : breeding of Guans in capti-
vity, ii. 191 ; behaviour of grouse
in captivity, ii. 192; sterility of the
partridge in captivity, ibid.

Tendrils in Cucurbitaceae, i. 431, ii.
380.

Tennent, Sir J. E., on the goose, i.
347 ; on the growth of the apple in
Ceylon, ii. 334 ; on the Jaffna sheep,
ii. 303.
Teredo, fertilisation in, ii. 435.

Terriers, wry-legged, ii. 396; white,
subject to distemper, ii. 404.

Teschemacher, on a husked form of
maize, i. 3S0.

Tessier, on the period of gestation of
Che dog, i. 4t : of the pig, i. 95 ; in
cattle, i. Ill : experiments on change
of soil, ii. 181.

Tetroo, breeding of species of, in cap-
tivity, ii. 191.

Tetmptt ryx parodist a, ii. 193.

Teucnum campamdatum, pelorisni in,
ii. 414.

Texas, feral cattle in, i. 109.

Theognis, his notice of the domestic
fowl, i. 298.

Theophrastus, his notice of the
peach, ii. 371.

Thssiwn, ii. 343.

Thompson, Mr., on the peach and nec-
tarine, i. 412 ; on the varieties of the
apricot, i. 414; classification of varie-
ties of cherries, i. 418, 419 ; on the
" Sister ribston-pippin," i. 421 ; on
the varieties of the gooseberry, i.
420, 427.

Thompson. William, on the pigeons
of Islay. i. 225 ; feral pigeons in Scot-
land, i. 233 : colour of the bill and
legs in geese, i. 34S ; breeding of
Tetroo SCOtius in captivity, ii. 191;
destruction of black-fowls by the
osprey, ii. 278.

Thompson, Prof. TV., on the obliquity
of the flounder, ii. 70.

Thorns, reconversion of, into branch-
es, in pear trees, ii. 383.

Thorn, grafting of early and late, i.
430; Glastonbury, i. 43a

Thrush, asserted reproduction of the
tarsus in a, ii. 36.

Th ;)' / :■'!'■'■ ::r A . an: a variety
of T. orientalis, i'. 486.

Thcret, on the division of the zoo-
spores of an alga, ii. 452.

Tuwaites. G. U., on the cats of Cey-

lon, i. 03; on a twin seed of Fuchsia

COCCith ii and /"/.'/< ''-'. i. 469.

TiBUBTirrs, experiments in rearing

wild ducks, i. 335.

Tiger, rarely fertile in captivity, ii.
185.

Tigridia conchiflora, bud-variation in,
i. 463.

Time, importance of. in the production
of races, ii. 293.

Tinzmann. self-impotence in the po-
tato, ii. 109.

Tissues, aflinityof, for special organic
substances, ii. 455.

Titmice, destructive to thin-shelled
walnuts, i. 429 ; attacking nuts, i.
430 ; attacking peas. ii. 279.

Tobacco, crossing of varieties of, ii.
130 ; cultivation of in Sweden, ii.
370.

Tobolsk, red-coloured cats of, i. 64.

Toes, relative length of, in fowls, i.
313 ; development of fifth in dogs, ii,
382.

Tollet, Mr., his selection of cattle, ii.
241.

Tomato, ii. 115.

Tomtits. See Tihnice.

Tongue, relation of, to the beak in
pigeons, i. 207.

Tooth, occurrence of a molar, in place
of an incisor, ii. 468,

"Tof.fschwein." i. 88.

Trail, R., on the union of half-tubers
of different kinds of potatoes, i. 475.

Trees, varieties of, suddenly pro-
duced, i. 434 ; weeping or pendulous,
i. 435 ; fastigate or pyramidal, i.
435 ; with variegated or changed
foliage, i. 435 ; early or late in leaf,
i. 430 ; forest, non-application of se-
lection to, ii. 2^7. ■»

"Trembleur" (pigeons), i. 181.

Tremblet, on reproduction in Hydra,
ii. 4-30.

"TREVOLTrai'" silkworms, i. 363-364.

Triehosanthes angvina, i. 434.

Tricks, inheritance of, ii. 15, 473.

TrifcAium minus and repens, ii. 200.

Trimorphic plants, conditions of re-
production in, ii. 221-225.

Tristram, H. B., selection of the dro-
medary, ii. 249.

Triticum dicoccum, i. 3S4.

Triticum monococcum, i. 384.

TriHcum tmeUa, i. 3S5.

Triticum turgidum, i. 884.

Triticum rndgan . wild in Asia, i. 377.
Triton, breeding in the branchiferous
stage, ii. 400.

"Trommel-Taube,'" i. 191.

"Tronfo" pigeon, i. 178,

Tropceolum, ii. 52.

"/// minus and mqfus, rever-
sion in hybrids of, i. 470-471.
Troubetzkoy, Prince, experiments

with pear-trees at Moscow, ii. 309.
Trousseau, Prof., pathological resem-
blance of twins, ii. 305.

564

TRUMPETER.

INDEX.

Trumpeter pigeon, i. 191 ; known in

• 1735, i. 252.

Tscuarner, H. A. de, graft-hybrid
produced by inosculation in the vine,
i. 474.

Tbchudi, on the naked Peruvian dog,
i. 37 ; extinct varieties of maize from
Peruvian tombs, i. 886, ii. 508.

Tubers, bud-variation by, i. 461-462.

Tuckerman, Mr., sterility of
rigida, ii. 207.

Tufted clucks, i. 339.

Tumps, variability of, i. 445 ; bud-va-
riation in, i. 463 ; influence of soil in
'•breaking," i. 403.

Tumbler pigeon, i. 184-190 ; short-
faced, figured, i. 182 ; skull figured,
i. 201; lower jaw figured, i. 203;
scapula and furcula figured, i. 200 ;
early known in India, i. 253 ; history
of, i. 254 ; sub-breeds of, i. 207 ;
young unable to break the egg-shell,
ii. 274 ; probable further modifica-
tion of, ii. 293.

"Tummler" (pigeons), i. 184.

Tumours, ovarian, occurrence of
hairs and teeth in, ii. 443 ; polypoid,
origin of, ii. 456.

" Turkische Taube," i. 173.

Turbit (pigeon), i. 184.

Turkey, domestic, origin of, i. 352-
354 ; crossing of with North Ameri-
can wild Turkey, i. 333 ; breeds of,
i. 353 ; crested white cock, i. 354 ;
wild, characters of, i. 354 ; degenera-
tion of, in India, i. 355, ii. 335 ; fail-
ure of eggs of, in Delhi, ii. 197 ; feral
on the Parana, i. 383 k change pro-
duced in by domestication, ii. 310.

Turkey, striped young pigs in, i. 99.

Turner (pigeon), i. 193.

Turner, W., on compensation in ar-
teries and veins, ii. 301 ; on cells, ii.
443.

Turnips, origin of, i. 392 ; reversion
in, ii. 45 ; run wild, ii. 48 ; crosses
of, ii. 118, 121 ; Swedish, preferred
by hares, ii. 281 ; acclimatisation of,
in India, ii. 374.

Turnspit, on an Egyptian monument,
i. 30 ; crosses of the, ii. 117.

Turtle-dove, white and coloured,
crossing of, ii. 117.

Tartar awritus, hybrids of, with T.
caiiilittij. iis'm and '-■ . i. 237.

Turtur risorvus, crossing of, with the
common pigeon, i. 230; hybrid of,
with 'J', vulgaris, i. 238.

Turtur sura&nsis, sterile hybrids of,
with T. vulgaris, i. 230 ; hybrids of,
with T. auritus, i. 237.

Turtur vulgaris, crossing of, with the
common pigeon, i. 230; hybrid of,
with T. rimrius, i. 236 ; sterile hy-
brids of, with T. mratensis and Ec-
lopwttx /rtif/ritforhis, i. 230-237.

Tusks of wild and domesticated pigs,
i. 98, 100.

Tussilago farfara, variegated, i. 461.

Twin-seed of Fuclisia coccinea and
fulgens, i. 409.

Tyerman, B., on the pigs of the Paci-
fic islands, i. 91, ii. Ill ; on the dogs
of the Pacific islands, ii. 111.

Ttlor, Mr., on the prohibition of con-
sanguineous marriages, ii. 152-153.

Udders, development of the, ii. 361.

Ulex, double-flowered, ii. 204.

campestris and <-//'«.>'«, hybrids
of, ii. 161.

Uniformity of character, maintained
by crossing, ii. 108-114.

Units of the body, functional inde-
pendence of the, ii. 441-444.

Unity or plurality of origin of organ-
isms, i. 24-25.

Upas poison, ii. 455.

Urea, secretion of, ii. 455.

Use and disuse of parts, effects of, ii.
356-365, 423. 500-501 : in rabbits, i.
155-159 ; in ducks, i. 343-346.

Utility, considerations of, leading to
uniformity, ii. 291.

Valentin, experimental production
of double monsters by, ii. 409.

VaOota, ii. 172.

Van Beck, Barbara, a hairy-faced wo-
man, ii. 13.

Van Mons on wild fruit-trees, i. 376,
ii. 314 ; production of varieties of the
vine, i. 401 ; correlated variability in
fruit-trees, ii. 398 ; production of
almond-like fruit by peach-seedlings,
i. 408.

Vanessa'^ species of, not copulating in
captivity, ii. 193.

Variability, i. 14-15, ii. 444447, 471-
474, 485-502 ; causes of, ii. 302-320 ;
correlated, ii. 384-400, 424-425, 501-
502 ; law of equable, ii. 422-423 ; ne-
cessity of, for selection, ii. 233 ; of
selected characters, ii. 288-289 ; of
multiple homologous parts, ii. 410-
411.

Variation, laws of, ii. 353-427 ; conti-
nuity of, ii. 291 ; possible limitation
of, ii. 291, 497-499 ; in domestic cats,
i. 02-05 ; origin of breeds of cattle by,
i. 112-113 ; in osteological characters
of rabbits, i. 145-102"; of important
organs, i. 432: analogous or parallel,
ii. 417-422; in horses, i. 73; in the
horse and ass, i. 83; in fowls, i. 294-
297 ; in geese, i. 34S ; exemplified in
the production of fleshy stems in
cabbages, &c, i. 392; in the peach,
nectarine, and apricot, i. 412, 415;
individual, in wheat, i. 379.

Variegation of foliage, i. 460, ii. 204,
205.

Varieties and species, resemblance
of, i. 15, ii. 491-492 ; conversion of,
into species, i. 15 : abnormal, ii. 493 ;
domestic, gradually produced, ii.
494.

Vakro, on domestic ducks-, i. 335 ; on

INDEX.

565

feral fowls, ii. IT: crossing of the
wild and domestic ass. ii. 850,
Vasbt, Mr., on the number of sacral

vertebra' in ordinary and tumped
cattle, i. 102 ; on Hungarian cattle, i.
103.

V.u-cuer, sterility of Ranunculus fi-
caria and Acorus calamus, ii. 208.

Vegetables, cultivated, reversion in.
ii. 15-46; European, culture of, in
India, ii. 200.

Vkitu. Mr., on breeds of horses, i, 66.
Verbascum, intercrossing of species
of. i. 405: ii. 118, 188-184; reversion
"in hybrids of, i. 471: contabescent,
wild plants of, ii. 90S, villosity in, ii.
336.
Verbascum austriacum ii. 1G9.

Verbascum bkUtaria, ii. 133-133.

Verbascum lychnltis, ii. 132-133, 169.
urn nigrum, ii. 169.

p< rbast "in pha niceum, ii. 181, 109 ; va-
riable duration of. ii. 307.

l", rbascumJJiapsus, ii. 134.

Verbenas" origin of, i. 438; white, lia-
bility oi, to mildew, ii. 876, 404 :
scorching of dark. ii. 277, 404 : effect
of changed conditions of life on, ii.
330.

Verlot, on the dark -leaved Barberry,
i. 435: inheritance of peculiarities
of foliage in trees, i. 435 : production
ot Rosa cannabif alia by bud-varia-
tion from B. alhii , i. 458 ; bud-varia-
tion in Aralia trtfc&iata, i. 469 ; va-
riegation of leaves, i. 460 : colours
of tulips, i. 463; uncertainty of in-
heritance, ii. 29 ; persistency of
white flowers, li. 31 : peloric flowers
of Lhriiin, ii. 77: tendency of striped
flowers to uniformity of colour, ii.
90 ; non-intercrossing of certain al-
lied plants, ii. 115: sterility of* Pri-
iniihi with coloured calyces, ii. 203;
on fertile proliferous Bowers, ibid. :
on the Irish yew, ii. 292; differences
in the Camellia, ii. 303; effect of
soil on the variegated strawberry, ii.
331 : correlated variability in plants,
ii. 397.

V< mica, ii. 71, 478.

Vertebrae, characters of, in rabbits, i.
151-153; in ducks, i. 311-342 : number
and variations of, in pigeons, i. 204-
205 : number and characters of, in
fowls, i. 321-323: variability of num-
ber of, in the pig, i. 96.

Vbbtuch, see Putsche.

'• Yerugas," ii. 333.

Vespucius, early cultivation in Brazil,
i. 876.

Vlbert's experiments on the cultiva-
tion of the vine from seed, i. 401.

Viburnum opulus, ii. 225. 380.

yicia saliva, leaflet converted into a
tendril in, ii. 469.

VICUNAS, selection of, ii. 251.

Vili.ositt, of plants, influenced by
dryness, ii. 335.

Yilmorin. cultivation of the wild car-
rot, i. 392, ii. 335 : colours of tulips, i.
: uncertainty Of inheritance in
balsams and roses, ii. 29; experi-
ments with dwarf varieties of Sapo-
naria c tlabi Sea and Tagi '"< signata,
ii. 31 : reversion of flowers by stripes
and blotches, ii. 51; on variability,
ii. 816.
Yima minor, sterility in. ii. 207.
Vine, i. 400-402: parsley-leaved, re-
version of, i. 459; graft-hybrid
produced by inosculation in the, i.
474 ; disease of. influenced by colour
of grapes, ii. 270; influence of cli-
mate, &c, on varieties of the, ii.
335: diminished extent of cultiva-
tion of the, ii. 370 : acclimatisation
of the, in the West Indies, ii. 377.
Viola, species of, i. 443.
Viola h utea, different coloured flowers

in, i. 490.
Vio/tt Iricolor, reversion in, ii. 45, 64.
Virchow, Prof., blindness occurring
in the offspring of consanguineous
marriages, ii. 77 : on the growth of
bones, "ii. 355,450: on cellular pro-
lification, ii. 355: independence of
the elements of the body, ii. 442 ; on
the cell-theory, ii. 443 ; presence of
hairs and teeth in ovarian tumours,
ii. 443; of hairs in the brain, ii.
468: special affinities of the tissues,
ii. 455 ; origin of polypoid excres-
cences and tumours, ii. 450.
Virgil on the selection of seed-corn,
i. 383, ii. 246; of cattle and sheep, ii.
245.
Virginian islands, ponies of, i. 70.
VirgiUaria, ii. 452.

Vision-, hereditary peculiarities of, ii.
17-19 : in amphibious animals, ii.
269 ; varieties of, ii. 302 ; affections
of organs of, correlated with other
peculiarities, ii. 395.
Wis vinifera, i. 400-403; 451.
1 "if- rra, sterility of species of, in cap-
tivity, ii. 184.
Vogel, varieties of the date palm, ii.

309.
Yoi.t. on the indications of stripes on

black kittens, ii. 73.
Voice, differences of, in fowls, i. 313 ;
peculiarities of, in ducks, i. 339 : in-
heritance of peculiarities of, ii. 15.
Volz, on the history of the dog, i. 39 :
ancient history of the fowl. i. 398;
domestic ducks unknown to Aristo-
tle, i. 335: Indian cattle sent to Ma-
cedonia by Alexander, ii. 245: men-
tion of mules in the Bible, ii. 211;
history of the increase of breeds, ii.
295.
Von Berg on Verbascum pho niceum,

ii. 307.
Voorhelm, G., his knowledge of hya-
cinths, i. I Hi, ii. 303.
Ykolik. Prof, on polydactylism, ii.
22 ; on double monsters, ii. 409 ; in-

566

INDEX.

WIEGMANN.

fluence of the shape of the mother's
pelvis on her child's head, ii. 413.

Waders, behaviour of, in confine-
ment, ii. 191.

Wahlenberg, on the propagation of
Alpine plants by buds, runnel's,
bulbs, &c, ii. 207.

" Wahlverwandtschaft " of Gart-
ner, ii. 219.

Wales, white cattle of, in the 10th
century, i. 109.

Walker, A., on intermarriage, i. 485 ;
on the inheritance of polydactylism,
ii. 24.

Walker, D., advantage of change of
soil to wheat, ii. 179.

Wallace, A. K., on a striped Java-
nese horse, i. 77 ; on the conditions
of life of feral animals, ii. 46 ; arti-
ficial alteration of the plumage of
birds, ii. 338; on polymorphic but-
terflies, ii. 478 ; on reversion, ii. 496 ;
on the limit of change, ii. 498.

Wallace, Dr., on the sterility of
Sphingidae hatched in autumn, ii.
193.

Waxlachian sheep, sexual peculiari-
ties in the horns of, i. 121.

Wallflower, bud-variation in, i. 458.

Wallich, Dr., on Thuja pendula or
filifonnis, i. 436.

Walnuts, i. 429 ; thin - shelled at-
tacked by tomtits, ii. 279 ; grafting
of, ii. 313.

Walsh, B. D., on galls, ii. 340-342; his
"Law of equable variability," ii.
422.

Walther, F. L., on the history of the
dog, i. 29 ; on the intercrossing of
the zebu and ordinary cattle, i. 106.

Waring, Mr., on individual sterility,
ii. 198.

Wart hog, i. 93.

Waterer, Mr., spontaneous produc-
tion of Cytisus alpuio-laburuum, i.
468.

Water melon, i. 430.

Waterhouse, G. E.,on the winter-
colouring of Lepus variabilis, i. 139.

Waterton, C., production of tailless
foals, i. 71 ; on" taming wild ducks, i.
335; on the wildness of half-bred
wild-ducks, ii. 62; assumption of
male characters by a hen, ii. 68.

Watson, H. C, on British wild fruit-
trees, i. 376 ; on the non-variation of
weeds, i. 382 ; origin of the plum, i.
415; variation in Pyrua mafott, i.
420 ; on Viola anvxna and tricolor, i.
443 ; on reversion in Scotch kail, ii.
45 ; fertility of Draba sylvestris when
cultivated, ii. 199 ; on generally dis-
tributed British plants, ii. 344.

Wattles, rudimentary, in some fowls,
ii. 379.

Watts, Miss, on Sultan fowls, i. 276.

Webb, James, interbreeding of sheep,
ii. 149.

Webee, effect of the shape of the
mother's pelvis on her child's head,
ii. 413.

Weeds, supposed necessity for their
modification, coincidently with cul-
tivated plants, i. 382.

Weeping varieties of trees, i. 435.

Weeping habit of trees, capricious in-
heritance of, ii. 29-30.

Weevil, injury done to stone fruit by,
in North America, ii. 279.

Welsh cattle-, descended from Bos
lo>i(/ifronx, i. 104.

West 'Indies, feral pigs of, i. 99 ; ef-
fect of climate of, upon sheep, i. 124.

Western, Lord, change effected by,
in the sheep, ii. 240.

Westphalia, striped young pigs in, i.
99.

Wlstwood, J. O., on peloric flowers
of Calceolaria, ii. 415.

Whatelt, Archbishop, on grafting
early and late thorns, l. 436.

Wheat, specific unity or diversity of,
i. 376-378, 381-382; Hasora, i. 378;
presence or absence of barbs in,
ibid. ; Godron on variations in, ibid. •
varieties of, i. 378-379 ; effects of soil
and climate on, i. 380 ; deterioration
of, i. 381 ; crossing of varieties of, i.
381; ii. 121, 131,161; in the Swiss
lake-dwellings, i. 3S2-385 ; selection
applied to, i. 383, ii. 242 ; increased
fertility of hybrids of, with dSgMops.
ii. 138 ; advantage of change of soil
to, ii. 179 ; differences of, in various
parts of India, ii. 201 ; continuous
variation in, ii. 242; red, hardiness
of, ii. 278, 404 ; Fenton, ii. 281 : natu-
ral selection in, ii. 281 ; varieties of,
found wild, ii. 313 ; effects of change
of. climate on, ii. 369; ancient vari-
ety of, ii. 573.

Whitby, Mrs., on the markings of
silkworms, i. 364 ; on the silkmoth,
i. 366.

White, Mr., reproduction of supernu-
merary digits after amputation, ii. •
24 ; time occupied in the blending of
crossed races, ii. 110.

White, Gilbert, vegetable diet of dogs,
ii. 365.

White and white-spotted animals, lia-
bility of, to disease, ii. 405-4U(i.

White flowers, most truly reproduced
by seed, ii. 31.

Wichura, Max, on hybrid willow3, ii.
67, 162, 322; analogy between the
pollen of old-cultivated plants, and
of hybrids, ii. 323.

Wicking, Mr., inheritance of the pri-
mary characters of Columba licia in
cross-bred pigeons, i. 245 ; produc-
tion of a white head in almond tum-
blers, ii. 241.

Wicksted, Mr., on cases of indivi-
dual sterility, ii. 198.

Wiegmann, spontaneous crossing of

INDEX.

567

blue and white peas, i. 477 ; cross-
ing of varieties of cabbage, ii. l(il ;
on contabescence, ii. 202.

Wihdt, Dr.. sexual sterility of plants
propagated by bade, &c ii. 207.

Wilde. Sir \v. R., occurrence of 50s
flxmtosus and umgifroms in Irish
crannoges, i. 104 ; attention paid to
breeds'of animals by the ancient
Irish, ii. 248.

Wildman, on the dahlia, ii. 262, 330.

Wii.dne-s of the progeny of crossed
tame animals, ii. 00-02.

Wilkes. Capt., on the taming of pi-
geons among the Polynesians, ii. 196.

Wilkinson, J., on crossed cattle, ii.
131.

Williams, Mr., change of plumage in
a Hamburgh hen, i. 311.

Williams. Mr., intercrossing of straw-
berries, i. 423.

Williamson, Capt., degeneration of
dogs in India, i. 53 ; on small Indian
asses, i. 82.

Williamson, Rev. W., doubling of
Anemone coronaria by selection, ii.
243.

Willows, weeping, i. 435 : reversion
of spiral-leaved weeping, i. 400 : hy-
brids of, ii. 322 ; galls of. ii. 310-311.

Willoughby, F., notice of spot pi-
geons, i. 192 : on a fantail pigeon, i.
253 ; on tumbler pigeons, i. 255 ; on
the turbit, i. 255 ; on the barb and
carrier pigeons, i. 257 ; on the hook-
billed duck, i. 334.

Wilmot. Mr., on a crested white Tur-
key cock, i. 354 ; reversion of sheep
in colour, ii. 44.

Wilson, B. O., fertility of hybrids of
humped and ordinary cattle in Tas-
mania, i. 107.

Wilson, Dr., prepotency of the Manx
over the common cat. ii. 86.

Wilson, James, origin of dogs, i. 28.

Wilson, Mr., on prepotency of trans-
mission in sheep, ii. 89 ; on the
breeding of bulls, ii. 238.

Wings, proportionate length of, in
different breeds of pigeons, i. 210-
217 : of fowls, effects of disuse on,
i. 327-829 : characters and variations
of, in ducks, i. 3-13-346 ; diminution
of, in birds of small islands, i. 346.

Wing-feathers, number of, in pi-
geons, i. 190 ; variability of, in fowls,
l. 312.

Wolf, recent existence of, in Ireland,
i. 28 : barking of young, i. 41 ; hy-
brids of, with the do^. i. 46.

Wolf-dog, black, of Florida, i. 36.

Wolves, North American, their re-
semblance, to dogs of the same re-
gion, i. 3446 : burrowing of, i. 41.

Woodbury, Mr., crossing of the Li-
gurian and common hive bees, i.
360, ii. 157 ; variability of bees, i. 359.

Woodward, S. P., on Arctic Mollusca,
ii. 309.

Wood, Willoughby, on Mr. Bates' cat-
tle, ii. 147.

Wooler, W. A., on the young of the
Himalayan rabbit, i. 137 ; persisten-
cy of the coloured calyx in a crossed
Polyanthus, i. 439.

Worrara poison, ii. 455.

Wounds, healing of, ii. 354.

Whisht, J., production of crippled
calves by short-horned cattle, ii.
147 ; on selection in cattle, ii. 236 ;
effect of close interbreeding on pigs,
ii. 151 ; deterioration of game cocks
by close interbreeding, ii. 155.

Wright. Strethill, on the development
of the hydroida, ii. 441.

Wtman, Dr., on Niata cattle, and on
a similar malformation in the cod-
fish, i. 113; on Virginian pigs, ii.
275.

Xenophon, on the colours of hunting

dogs, ii. 254.
Ximenes, Cardinal, regulations for the

selection of rams, ii. 247.

" Yahoo," the name of the pigeon in
Persia, i. 192.

Yaks, domestication of, i. 105 ; selec-
tion of white-tailed, ii. 249, 253.

Yam, development of axillary bulbs
in the, ii. 206.

Yarrell, Mr., deficiency of teeth in
hairless dogs, i. 49, ii. 393 ; on ducks,
i. 337, ii. 316 ; characters of domestic
goose, resembling those of Aneer
(dO/fron-*, i. 347 ; "whiteness of gan-
ders, i. 34S ; variations in goldfish, i.
357-358 ; assumption of male plu-
mage by the hen-pheasant, ii. 68 ; ef-
fect of castration upon the cock, ii.
69 ; breeding of the skylark in cap-
tivity, ii. 189 ; plumage of the male
linnet in confinement, ii. 193 ; on the
dingo, ii. 317.

Yellow fever, in Mexico, ii. 333.

Yew, fastigate, ii. 292.

Yew, Irish, hardy in New York, ii.
371.

Yew, weeping, i. 435 ; propagation of,
by seed, ii. 29.

Yolk, variations of, in the eggs of
ducks, i. 339.

Youatt, Mr., history of the dog, i.
29 ; variations of the pulse in breeds
of dogs, i. 51 ; liability to disease in
dogs, i. 51, ii. 275; inheritance of
goitre in dogs, ii. 20; on the grey-
hound, i. 49, 57 ; on King Charles'
spaniels, i. 57 ; on the setter, i. 57 ;
on breeds of horses, i. 66 ; variation
in the number of ribs in the horse,
i. 07 ; inheritance of diseases in the
horse, ii. 20 ; introduction of East-
ern blood into English horses, ii.
257-258; on white Welsh cattle, i.
UK), ii. 253; improvement of British
breeds of cattle, i. 118; rudiments
of horns in young hornless cattle, ii.

568

INDEX.

ZOPF-TAUBE.

74, 379 ; on crossed cattle, ii. 131,
148 ; on BakewelTs long-horned cat-
tle, ii. 146 ; selection of qualities in
cattle, ii. 237 ; degeneration of cat-
tle by neglect ;:. 289; on the skull
in hornless cattle, ii. 401 ; disease of
white parts of cattle, ii. 406 ; dis-
placement of long-horned by short-
horned cattle, ii. 509 ; on Angola
sheep, i. 120 ; on the fleece of sheep,
i. 125 ; correlation of horns and
fleece in sheep, i. 120 ; adaptation of
breeds of sheep to climate and pas-
ture, i. 122 ; horns of Wallachian
sheep, i. 121 ; exotic sheep in the
Zoological Gardens, i. 122, ii. 368 ;
occurrence of horns in hornless
breeds of sheep, ii. 43 ; on the col-
our of sheep, ii. 44 : on interbreed-
ing sheep, ii. 149 : on Merino rams
in Germany, ii. 238 ; effect of uncon-
scious selection on sheep, ii. 258 ;
reversion of Leicester sheep on the
Lammermuir Hills, ii. 272 ; on many-
horned sheep, ii. 392 ; reduction of
bone in sheep, ii. 293 ; persistency of
character in breeds of animals in
mountainous countries, ii. 84; on

interbreeding, ii. 145 ; on the power
of selection, ii. 235-237 ; slowness of
production of breeds, ii. 295 ; pas-
sages in the Bible relating to the
breeding of animals, ii. 244.

Young, J., on the Belgian rabbit, i.
134

Yule, Capt., on a Burmese hairy fam-
ily, ii. 98, 394.

Zambesi, striped young pigs on the, i.

99.
Zambos, character of the, ii. 03.
Z^no, J. G., introduction of rabbits

into Porto Santo by, i. 141.
Zed Mays, i. 385-386.
Zebu, i. 101-102 ; domestication of the,

i. 105 ; fertile crossing of, with Eu-
ropean cattle, i. 106, ii. 138.
Zebra, hybrids of, with the ass and

mare, ii. 58.
Zephyranthes Candida, ii. 200.
Zinnia, cultivation of, ii. 315.
Zollinger on Malayan penguin ducks,

i. 33S.
Zoospore, division of, in Alga?, ii.

452.
" Zopf-Taube," i. 190.

VALUABLE AND BEAUTIFUL WORK.

HARRIS'

Insects Injurious to Vegetation.

BT THE LATE

THADDEUS WILLIAM HARRIS, JO.

A New Edition, enlarged and improved, with additions from the author's
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ooisTTEnsTrrs.

CHAPTER I.

INTRODUCTION.— Insects Denned— Brain and Nerves— Air-Pipes and Breath-
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Classification ; Orders and Groupe.

CHAPTER II.

COLEOPTERA — Beetles— Scarabseians— Ground-Beetles— Tree-Beetles— Cock-
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CHAPTER IV.

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Tree-Hoppers— Vine-Hoppers — Plant-Lice — American Blight— Bark-Lice.

CHAPTER V.

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CHAPTER VII.

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ing hundreds of beautiful and (?istruclive Engravings In every annual volume.

It contains each month a Calendar of Operations to be performed on the Farm,
In the Orchard and Garden, in and around the Dwelling, etc.

The thousands of hints and suggestions given in every volmne are prepared by prac-
tical, intelligent working men, who know what they talk and write about. The
articles are thoroughly edited, and every way reliable.

The Household Department is valuable to every Housekeeper, affording
very mauy useful hints and directions calculated to lighten and facilitate in-door work.

The Department for Children and Youth, is prepared with special care
not only to amuse, but also to inculcate knowledge and sound moral principles.

Terms— The circulation of the American Agriculturist, falmut 150,000) Is bo

large that it can be furnished at the low price of $1.50 a year ; four copies, one year, for
$5; ten copies, one year, for $12; twenty or more copies, one year. $1 each; 6ingle
copies, 15 cents each. An extra copy to the one furnishing a club of ten or twenty.

TRY IT A. YE.AJR.

ORANGE JTJDD & CO.,
Publishers & Proprietors,

JNo. 245 Broadway, New- York City/

4=c^ — , =#=>#>

Ilanbscape G-^.ttT>^:isi.TSG-.SL

" Downing's Landscape Gardening and Rural "

Architecture.

Price, $6.50.

The most complete and valuable work ever Issued on Landscape Gardening In
North-America, for the Improvement of Country Residences; containing full Direc-
tions for every thing connected with Laying out and adorning the Rural Home, the
Grounds, the Gardens, the Buildings, the Trees and Plants, etc., with principles of
taste so Btated as to adapt the work to all classes. Splendidly Illustrated with many
Steel and fine Wood Engravings. By the late A. J. Downing. New Edition, En-
larged, Newly Illustrated and Revised, with Supplement, by Henry Winthrop Sar-
gent. Octavo, 5!U pp. Extra cloth, gilt, beveled boards.

This Edition contains a Splendid new portrait on Steel, of Mr. Downxno.

HORSES.

Herbert's Hints to Horse-Keepers, - - - {New Edition.)

Price, $1.75.

This is the best practical work on the Horse, prepared m this country. A Complbt*
Manual for Horsemen, embracing: How to Breed a Horse; How to Buy a Horse;
How to Break a Horse; How to Use a Horse'; How to Feed a Horse; How to Physic a
Horse (Allopathy or Homoeopathy) ; How to Groom a Horse ; How to Drive a Horse;
1 How to Ride a Horse, etc., and Chapters on Mules and Ponies, etc. By the late
Henry William Herbert (Prank Forrester). Beautifully Illustrated throughout.
Cloth, «mo„ 425 pp.

BEES.

Quinby's Mysteries of Bee-Keeping Explained.

Price, $1.50.

Newly written throughout, containing the results of thirty-five years of successful
experience, with full, plain, and practical Directions for all details of Bee Culture;
Including also a Description and Manner of Using the Movable Comb and Box Hives,
with the most approved modes of Propagating and Treating the Italian Bee, etc., etc
with numerous Illustrations. By M. Quinby, Practical Bee-Keepcr.

NEW-YORK :

PUBLISHED BY

uORANGB JUDD & OO.J

Breck's New Book of Flowers.

BY JOSEPH BRECK,

PRACTICAL HORTICULTURIST.

BEAUTIFULLY ILLUSTRATED.

This work, while preserving scientific accuracy, is written in a familiar
etjle, and with the enthusiasm of a life-long lover of flowers.

The lessons of a practical acquaintance with the subject are plainly
given, and though the author is never dry, his teachings are full of

PRACTICAL COMMON SENSE.

ALL DEPARTMENTS OP OUT-DOOR GARDENING

are treated, and the work really condenses into one volume what is in
many cases distributed through several treatises on Bulbs, Annuals, Roses, etc.

Bulbs. The cultivation of bulbs, whether iudoors or in the open
ground, is clearly described, and such instructions are given as will insure
success with these favorite plants.

Annuals. All the finer annuals are described, and the peculiar
treatment necessary for each given in full.

Herbaceous Perennials. This justly favorite class of plants
is given here more at length than in any work with which we are acquainted.

Bedding Plants. The treatment of the popular kinds of bed-
ding plants is given, together with that of Dahlias, Chrysanthemums, and
such as usually fall under the head of florist's flowers.

Flowering Shrubs. A separate section is devoted to the hardy
flowering shrubs, including a very full chapter upon the Rose.

We have no work which is so safe a guide to the novice in gardening,
or that Imparts the necessary information in a style so free from techni-
calities. Not the least interesting part of the work is the author's personal
experience, as he tells not only how he succeeded, but the mistakes he
committed. Thus far it is

"THE BOOK OF FLOWERS."
Sent post-paid. Price, $1.75.

ORANGE JUDD & CO.,

24:5 Broadway.

DRAINING FOR PROFIT,

AND

DRAINING FOR HEALTH.

BY

GEO. E. WARING, Jr.,

ENGINEER OF THE DRAINAGE OF THE CENTRAL PARK, NEW-YORK.

" EVERY REPORTED CASE OF FAILURE IN DRAINAGE WHICH WE HAVE INVESTI-
GATED. HAS RESOLVED ITSELF INTO IGNORANCE, BLUNDERING, BAD MANAGEMENT,

ob bad execution."— Glsborne.

ILLUSTRATED.

CONTENTS:

Chapter I.— LAND TO BE DRAINED AND THE REASONS

WHY.
Chapter II.— HOW DRAINS ACT, AND HOW THET AFFECT

THE SOU..
Chapter III.— HOW TO GO TO WORK TO LAY OUT A

SYSTEM OF DRAINS.
Chapter rV.— HOW TO MAKE THE DRAINS.
Chapter V.— HO "IV TO TAKE CARE OF DRAINS AND

DRAINED LANDS.
Chapter VI.-AVHAT DRAINING COSTS.
Chapter VII. -AVILL IT PAYS

Chapter VTII.— HOW TO MAKE DRAINING TILES.
Chapter IX.— THE RECLAIMING OF SALT MARSHES.
Chapter X.— MALARIAL DISEASES.
Chapter XL-HOUSE AND TOWN DRAINAGE.

Sent post-paid. Price $1.50.

NEW-YORK:

ORANGE JUDD & CO., 245 Broadway.