“EON: DON
| dG; iN MURRAY.

J

THE VARIATION

OF

ANIMALS AND PLANTS

UNDER DOMESTICATION.

By CHARLES DARWIN, M.A., F.RB.S., &c.

IN TWO VOLUMES.—Vox. II.

WITH ILLUSTRATIONS.

LONDON:
JOHN MURRAY, ALBEMARLE STREET.

1868.

The right of Translation is reserved,

ee ee ee ee ee ee a ~* Ce a ee Te os a ee

BY THE SAME AUTHOR.
EAE eae

ON THE ORIGIN OF SPECIES BY MEANS OF NATURAL

SELECTION ; or The Preservation of Favourep Racers in the SrruceLE for
Lire. Fourth Edition (Highth Thousand), with Additions and Corrections. Post 8vo.,
15s. 1866. MurRAY.

A NATURALISTS VOYAGE ROUND THE WORLD; or, A

J OURNAL OF RESEARCHES into the NATURAL History and Grotoey of the CounTriks
visited during the Voyage of H.M.S. Beagle, under the Command of Capt. Firz-
Roy, R.N. Tenth Thousand. Post 8vo.,9s. 1860. Murray.

ON THE STRUCTURE AND DISTRIBUTION OF CORAL
REEFS. Smitu, ELprr, & Co.

GEOLOGICAL OBSERVATIONS ON VOLCANIC ISLANDS.

Situ, Exper, & Co.

GEOLOGICAL OBSERVATIONS ON SOUTH AMERICA.

Surry, Exper, & Co.

A MONOGRAPH OF THE CIRRIPEDIA. With numerous Illus-

trations. 2 vols. 8vo. HARDWICKE.

ON THE VARIOUS CONTRIVANCES BY WHICH BRITISH

AND FOREIGN ORCHIDS ARE FERTILISED BY INSECTS; and on the Goop
Errects of Crossing. With numerous Woodcuts, Post 8vo., 9s. 1862. Murray.

ON THE MOVEMENTS and HABITS of CLIMBING PLANTS.
With Woodcuts. WI.LiaAMs & NORGATE.

LONDON : PRINTED BY WILLIAM CLOWES AND SONS, STAMFORD STREET,
AND CHARING CROSS.

CONTENTS “OF “VOLUME: TE

CHAPTER XII

INHERITANCE.

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

-ANDS VARIABILITY, AND BY REVERSION — CONCLUSION Se ee a a wey

CHAPTER XIII.

INHERITANCE continued — REVERSION OR ATAVISM.

a DIFFERENT FORMS OF REVERSION — IN PURE.OR UNCROSSED BREEDS, AS IN PIGEONS,

FOWLS, HORNLESS CATTLE AND SHEEP, IN CULTIVATED PLANTS — REVERSION IN
aR [TISH FERAL ANIMALS AND PLANTS — REVERSION IN CROSSED VARIETIES AND SPECIES—
n the Good REVERSION THROUGH BUD-PROPAGATION, AND BY SEGMENTS IN THE SAME FLOWER
{vRBAI. 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 — ARPEARANCE 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 3? 8

CHAPTER XIV.

INHERITANCE continued — FIXEDNESS OF CHARACTER — PREPO-
TENCY — SEXUAL LIMITATION — CORRESPONDENCE OF AGE.

FIXEDNESS OF CHARACTER APPARENTLY NOT DUE TO ANTIQUITY OF INHERITANCE —

PREPOTENCY OF TRANSMISSION IN INDIVIDUALS OF THE SAME FAMILY IN CROSSED

BREEDS AND SPECIES; OFTEN STRONGER IN ONE SEX THAN THE OTHER: SOME-

TIMES DUE TO THE SAME CHARACTER BEING PRESENT AND VISIBLE IN ONE BREED

AND LATENT IN THE OTHER — INHERITANCE AS ‘LIMITED BY SEX — NEWLY-

st, ACQUIRED CHARACTERS IN OUR DOMESTICATED ANIMALS OFTEN TRANSMITTED BY
SOMETIMES LOST BY ONE SEX ALONE — INHERITANCE AT COR-~

a2

ONE SEX ALONE,

CONTENTS OF VOL. II.

RESPONDING PERIODS OF LIFE — THE IMPORTANCE OF THE PRINCIPLE WITH RESPECT
TO EMBRYOLOGY; AS EXHIBITED IN DOMESTICATED ANIMALS; AS EXHIBITED IN
THE APPEARANCE AND DISAPPEARANCE OF INHERITED DISEASES; SOMETIMES
SUPERVENING EARLIER IN. THE CHILD THAN IN THE PARENT — SUMMARY OF THE
THREE PRECEDING CHAPTERS) 60 ses bet ne ae we ee Pag G2

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 TRANS-
MISSION, BY THE CONDITIONS OF LIFE, AND BY NATURAL SELECTION — ALL ORGANIC
BEINGS OCCASIONALLY INTERCROSS; APPARENT EXCEPTIONS — ON CERTAIN
CHARACTERS INCAPABLE OF FUSION; CHIEFLY OR EXCLUSIVELY THOSE WHICH
HAVE SUDDENLY APPEARED IN THE INDIVIDUAL — ON THE MODIFICATION OF OLD
RACES, AND THE FORMATION OF NEW RACES, BY CROSSING — SOME CROSSED RACES
HAVE BRED TRUE FROM THEIR FIRST PRODUCTION — ON THE CROSSING OF DISTINCT
SPECIES IN RELATION TO THE FORMATION OF DOMESTIC RACES... ae oe Nir aot,

CHAPTER XVI.

CAUSES WHICH INTERFERE WITH THE FREE CROSSING OF

VARIETIES — INFLUENCE OF DOMESTICATION ON FERTILITY.

DIFFICULTIES IN JUDGING OF THE FERTILITY OF VARIETIES WHEN CROSSED —

VARIOUS CAUSES WHICH KEEP VARIETIES DISTINCT, AS THE PERIOD OF BREEDING
AND SEXUAL PREFERENCE — VARIETIES OF WHEAT SAID TO BE STERILE WHEN
CROSSED — VARIETIES OF MAIZE, VERBASCUM, HOLLYHOCK, GOURDS, MELONS, AND
TOBACCO, RENDERED IN SOME DEGREE MUTUALLY STERILE — DOMESTICATION
ELIMINATES THE TENDENCY TO STERILITY NATURAL TO SPECIES WHEN CROSSED
—ON THE INCREASED FERTILITY OF UNCROSSED ANIMALS AND PLANTS FROM
DOMPPTICAUION AND COMMLVATION “is. 60 Seo lui ee a ck 100

CHAPTER XVII.

ON THE GOOD EFFECTS OF CROSSING, AND ON THE EVIL

EFFECTS OF CLOSE INTERBREEDING.

DEFINITION OF CLOSE INTERBREEDING — AUGMENTATION OF MORBID TENDENCIES —

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

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100

CONTENTS OF VOL. II. v

CHAPTER XVIII.

ON THE ADVANTAGES AND DISADVANTAGES OF CHANGED

CONDITIONS OF LIFE: STERILITY FROM VARIOUS CAUSES.

ON THE GOOD DERIVED FROM SLIGHT CHANGES IN THE CONDITIONS OF LIFE—

STERILITY FROM CHANGED CONDITIONS, IN ANIMALS, IN THEIR NATIVE COUNTRY
AND IN MENAGERIES—MAMMAILS, BIRDS, AND INSECTS— LOSS OF SECONDARY
SEXUAL CHARACTERS AND OF INSTINCTS— CAUSES OF STERILITY — STERILITY
OF DOMESTICATED ANIMALS FROM CHANGED CONDITIONS — SEXUAL INCOMPATI-
BILITY OF INDIVIDUAL ANIMALS — STERILITY OF PLANTS FROM CHANGED CONDI-
TIONS 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—HINCIPIENT STERILITY THE PRIMARY CAUSE OF DOUBLE
FLOWERS AND SEEDLESS FRUIT .. ak ei EE cake wr ape eee CR LES

CHAPTER XIX.

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

ON THE EFFECTS OF CROSSING — THE INFLUENCE OF DOMESTICATION ON FERTILITY

——CLOSE INTERBREEDING — GOOD AND EVIL RESULTS FROM CHANGED CONDITIONS
OF LIFE — VARIETIES WHEN CROSSED NOT INVARIABLY FERTILE— ON THE DIF-
FERENCE IN FERTILITY BETWEEN CROSSED SPECIES AND VARIETIES —- CONCLUSIONS
WITH RESPECT TO HYBRIDISM — LIGHT THROWN ON HYBRIDISM BY THE ILLEGITI-
MATE PROGENY OF DIMORPHIC AND TRIMORPHIC PLANTS — STERILITY OF CROSSED
SPECIES DUE TO DIFFERENCES CONFINED TO THE REPRODUCTIVE SYSTEM — NOT
ACCUMULATED THROUGH NATURAL SELECTION — REASONS WHY DOMESTIC VARIETIES
ARE NOT MUTUALLY STERILE— TOO MUCH STRESS HAS BEEN LAID ON THE

DIFFERENCE IN FERTILITY BETWEEN CROSSED SPECIES AND CROSSED VARIETIES —
CONOLUSION, 337005 agai 2 PR eed te ee ae eee ree ee fas

CHAPTER XX.

SELECTION BY MAN.

SELECTION A DIFFICULT ART — METHODICAL, UNCONSCIOUS, AND NATURAL SELECTION

— RESULTS OF METHODICAL SELECTION — CARE TAKEN IN SELECTION — SELECTION
WITH PLANTS — SELECTION CARRIED ON BY THE ANCIENTS, AND BY SEMI-CIVILISED
PEOPLE — UNIMPORTANT CHARACTERS OFTEN ATTENDED TO — UNCONSCIOUS SELEC-
TION — 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... «es ~—:192

vi CONTENTS OF VOL. IL.

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 PREVENTING CROSSES, AND
THE NATURE OF THE CONDITIONS — CLOSE ATTENTION AND PERSEVERANCE INDIS-
PENSABLE — 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 IMPORTANT — MANNER IN WHICH DOMESTIC RACES
HAVE ORIGINATED -— SUMMARY 66 os ei ela sa Page 224

CHAPTER XXII.

CAUSES OF VARIABILITY.

VARIABILITY DOES NOT NECESSARILY ACCOMPANY REPRODUCTION — CAUSES ASSIGNED
BY VARIOUS AUTHORS — INDIVIDUAL DIFFERENCES — VARIABILITY OF EVERY KIND
DUE TO CHANGED CONDITIONS OF LIFE— ON THE NATURE OF SUCH CHANGES —
CLIMATE, FOOD, EXCESS OF NUTRIMENT — SLIGHT CHANGES SUFFICENT — EFFECTS
OF GRAFTING ON THE VARIABILITY OF SEEDLING-TREES — DOMESTIC PRODUCTIONS
BECOME HABITUATED TO CHANGED CONDITIONS — ON THE ACCUMULATIVE ACTION
OF CHANGED CONDITIONS — CLOSE INTERBREEDING AND THE IMAGINATION OF THE
MOTHER SUPPOSED TO CAUSE VARIABILITY — CROSSING AS A CAUSE OF THE APPEAR-
ANCE 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,
Nee MRO eh en ye a dary, se ae ae ie ee: SO

CHAPTER XXIII.

DIRECT AND DEFINITE ACTION OF THE EXTERNAL CONDITIONS |
OF LIFE.

SLIGHT MODIFICATIONS IN PLANTS FROM THE DEFINITE ACTION OF CHANGED CONDITIONS, q
IN SIZE, COLOUR, CHEMICAL PROPERTIES, AND IN THE STATE OF THE TISSUES —
LOCAL DISEASES — CONSPICUOUS 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 INFLUENCE OF CHANGED EXTERNAL CONDITIONS — PARALLEL SERIES
OF VARIETIES — AMOUNT OF VARIATION DOES NOT CORRESPOND WITH THE DEGREE
OF CHANGE IN THE CONDITIONS — BUD-VARIATION — MONSTROSITIES PRODUCED

BY UNNATURAL TREATMENT — SUMMARY «- ee eu we te wet 271

STIC RAcks

CONTENTS OF VOL. TI. i

CHAPTER XXIV.

LAWS OF VARIATION — USE AND DISUSE, ETC.

NISUS FORMATIVUS, OR THE CO-ORDINATING POWER OF THE ORGANISATION — 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 ee ee ee ee et ras |

ee ee

CHAPTER xx ¥:

LAWS OF VARIATION, continued — CORRELATED VARIABILITY.

EXPLANATION OF TERM — CORRELATION AS CONNECTED WITH DEVELOPMENT —

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 — BETWEEN THE SKIN AND DERMAL APPENDAGES
— BETWEEN THE ORGANS OF SIGHT AND HEARING — CORRELATED MODIFICATIONS
IN THE ORGANS OF PLANTS — CORRELATED MONSTROSITIES — CORRELATION BE-
TWEEN 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

baie s sane ae ee

CHAPTER AAV.

LAWS OF VARIATION, continued — SUMMARY.

ON THE AFFINITY AND COHESION OF HOMOLOGOUS PARTS — ON THE VARIABILITY OF

PRELIMINARY REMARKS — FIRST PART : — THE FACTS

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 CAPSULE, AS INDUCING VARIATION — ANALOGOU

S OR
PARALLEL VARIETIES — SUMMARY OF THE THREE LAST CHAPTERS

339

CHAPTER 2 2ey Li.
PROVISIONAL HYPOTHESIS OF PANGENESIS.

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 NECESSARY ASSUMP-

TIONS ARE IMPROBABLE — EXPLANATION BY AID OF THE HYPOTHESIS OF THE

SEVERAL CLASSES OF FACTS SPECIFIED IN THE FIRST PART — CONCLUSION

oe BOT

vill CONTENTS OF VOL. II.

CHAPTER XXVIII.

CONCLUDING REMARKS.

DOMESTICATION — NATURE AND CAUSES OF VARIABILITY — SELECTION — DIVER-
GENCE AND DISTINCTNESS OF CHARACTER — EXTINCTION OF RACES — CIRCUM-
STANCES FAVOURABLE TO SELECTION BY MAN — ANTIQUITY OF CERTAIN RACES —
THE QUESTION WHETHER EACH PARTICULAR VARIATION HAS BEEN SPECIALLY PRE-
ATO ali Saak tk att ce ad tag M0 8 2 0 anh ng ee ORD

INDEX ee tee eC ee he EG yogic es bie 8 fae, 94 A OO

THE

VARIATION OF ANIMALS AND PLANTS

UNDER DOMESTICATION,

CHAPTER XII

INHERITANCE,

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

THE subject of inheritance is an immense one, and has been
treated by many authors. One work alone, ‘De VHérédité
Naturelle,’ 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.

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 remarked, probably no two individuals are
VOL. IL. B

@

2 INHERITANCE. Cuap, XIl.

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 millions on millions of
other men. Some authors have gone so far as to maintain that
the production of slight differences is as much a necessary func-
tion 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 may be, it generally 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 to the species,
should be transmitted through the male or female sexual cells,
which are so minute as not to be visible to the naked eye,
and afterwards 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-ascertained fact
that the minute ovule of a good milking 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 sur-
prise is, as Sir A. Holland has well remarked,’ 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 trans-
mitted from generation to generation.

1 ‘Medical Notes and Reflections,’ 3rd edit., 1855, p. 267.

AD \

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"It holds
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Cuap, XIL INHERITANCE, 8

Some writers, 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 together ? They might ask whether
the half-wild Arabs were led by theoretical notions to keep
pedigrees of their horses ? Why have pedigrees been scrupu-
lously kept and published of the Shorthorn cattle, and more
recently of the Hereford breed? Is it an illusion that these
recently improved animals safely transmit their excellent qua-
lities even when crossed with other breeds? have the Short-
horns, without good reason, been purchased at immense 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 ex-
tended back for a century. With pigs, the Yorkshire and Cum-
berland breeders “preserve 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 afterwards
sold to the Rev. F. Thursby for 65 guineas; who writes,
“she paid me very well, having sold her produce for 3002.
and having now four breeding sows from her.”* Hard cash
paid down, over and over again, is an excellent test of in-
herited superiority. In fact, the whole art of breeding, from
which such great results have been attained during the pre-
sent century, depends on the inheritance of cach small

2 Mr. Buckle, in hig grand work on ‘Animals of the British Islands,’ 1845,
‘ Civilisation,’ expresses doubts on the p. 721. For game-fowls, see ‘ The
subject owing to the want of statistics, Poultry Book, by Mr. Tegetmeier,
See also Mr. Bowen, Professor of Mora] 1866, p. 123. For pigs, see Mr. Sidney’s

Philosophy, in ‘Proc. American Acad. edit. of ‘Youatt on the Pig,’ 1860, pp.
of Sciences,’ vol. v. p. 102. 11, 22.

3 For greyhounds, see Low’s ‘ Domest.

hig.

4 INHERITANCE. Cuap, XII,

detail of structure. But inheritance is not certain; for if it
were, the breeder’s art* would be reduced to a certainty, and
there would be little scope left for all that skill and perse-
verance shown by the men who have left an enduring monuv-
ment 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 con-
versing with breeders. 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
im the history of the world, but have reappeared in several of the
children and grandchildren. Thus Lambert, “the porcupine-
man,” whose skin was thickly covered with warty projections,
which were periodically moulted, had all his six children and
two grandsons similarly affected. The face and body being
covered 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 woman® with a completely hairy face was exhibited in
London in 1668, and another instance has recently occurred.
Colonel Hallam’? 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 remarkable peculiarity, such as solid-hoofed swine,
Mauchamp sheep, niata cattle, &c., are instances of the long-
continued inheritance of rare deviations of structure.

When we reflect that certain extraordinary peculiarities have

4 ¢The Stud Farm,’ by Cecil, p. 39. the males alone.

5 Philosophical Transactions,’ 1755, 6 Barbara Van Beck, figured, as lam
p. 23. I have seen only second-hand informed by the Rev. W. D. Fox, in
accounts of the two grandsons. Mr. Woodburn’s ‘Gallery of Rare Portraits,’
Sedgewick, in a paper to which I shall 1816, vol. ii.
hereafter often refer, states that four 7 «Proc. Zoolog. Soc.,’ 1833, p. 16.
generations were affected, and in each

Cuar. XII, INHERITANCE, g

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 extraordinary peculiarity has
sometimes appeared in individuals living under widely different
conditions of life, we are driven to conclude that such peculia-
rities are not directly due to the action of the surrounding con-
ditions, 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 character
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 supposed, to mere coin-
cidence, but must be consequent on the members of the same
family inheriting something in 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 @ priori chance that an individual taken at random
will be so affected is only one in a million. Let the popula-
tion consist of sixty millions, composed, we will assume, of ten
million families, each containing six members. On these data,
Professor 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 peculiarity in ques-
tion, 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 become 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 English 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

6 INHERITANCE. CuaP, XII,

a similar lock on the same side, and his mother on the opposite
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 com-
bination of corporeal structure, mental character, and training,
must handwriting depend! yet every one must have noted the
occasional close similarity of the handwriting in father and son,
although the father had not taught his 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 of hand-
writing ; and it has even been asserted that English boys when
taught to write in France naturally cling to their English manner
of writing. Gait, gestures, voice, and general bearing are all
inherited, as the illustrious Hunter and Sir A. Carlisle have
insisted. 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 father who generally slept on his back,
with his right leg crossed over the left, and whose daughter,
whilst an infant in the cradle, followed exactly the same habit,
though an attempt was made to cure her.'? JI will give one
instance which has fallen under my own observation, and which
is curious from being a trick associated with a peculiar 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 excited, 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
concealed it. He had eight children. Of these, a girl, when

8 Hofacker, ‘Ueber die EHigenschaf- ‘Med. Researches,’ p. 530. Sir A. Car-
ten,’ &¢., 1828, 8.34. Report by Pariset __lisle, ‘ Phil. Transact.,’ 1814, p. 94.

in ‘ Comptes Rendus,’ 1847, p. 592. © Girou de Buzareignues, ‘De la
9 Hunter, as quoted in Harlan’s Génération,’ p. 282.

Cuar. XII. INHERITANCE. 7

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 her face, in exactly the same manner as her
father had done, and sometimes even still continued to do when
alone. I never heard of any one excepting this one man and his
little daughter who had this strange habit; and certainly imita-
tion 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 paper ™ on hereditary talent will have his
doubts allayed.

Unfortunately it matters not, as far as inheritance is con-
cerned, how injurious a quality or structure may be if compatible
with life. No one can read the many treatises? on hereditary
disease and doubt this. ‘The ancients were strongly of this
opinion, or, as Ranchin expresses it, Omnes Grecit, Arabes, et
Latint 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 hospital 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 surgeon,
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 suc-
cessive generations, have committed suicide, Striking instances

il « Macmillan’s Magazine,’ July and
August, 1865.

12 The works which I have read and
found most useful are Dr. Prosper Lu-
cas’s great. work, ‘ Traité de ?Hérédité
Naturelle,’ 1847. Mr. W. Sedgwick, in
‘ British and Foreign Medico-Chirurg.
Review,’ April and July, 1861, and
April and July, 1863: Dr. Garrod on
Gout is quoted in these articles. Sir
Henry Holland, ‘Medical Notes and
Reflections,’ 3rd edit., 1855. Piorry,

‘De l’Hérédité dans les Maladies,’ 1840.
Adams, ‘A Philosophical Treatise on
Hereditary Peculiarities,’ 2nd edit.,
1815. Essay on ‘Hereditary Diseases,’
by Dr. J. Steinan, 1843. See Paget, in
‘Medical Times,’ 1857, p. 192, on the
Inheritance of Cancer; Dr. Gould, in
‘Proc. of American Acad. of Sciences,’
Nov. 8, 1853, gives a curious case of
hereditary bleeding in four genera-
tions. Harlan, ‘Medical Researches,’
p. 993.

8 INHERITANCE. CuHap, XIf,

have been 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 parturition
being inherited. In this latter respect I may mention an odd
case given by a good observer,’ 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 mon-
strous size of the buttocks of the calf was frequently fatal to the
cow, and numbers of cows were annually lost in calving.”

Instead of giving numerous details on various inherited malformations
and diseases, I will confine myself to one organ, that which is the most
complex, delicate, and probably best-known in the human 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. Carlisle“ specifies a pendulous fold to
the eyelids as inherited. “ In a family,” says Sir H. Holland,” “where the
father had a singular elongation of the upper eyelid, seven or eight children
were born with the same deformity; two or three other children having
it not.” Many persons, as I hear from Mr. Paget, have two or three of
the hairs in their eyebrows (apparently corresponding with the vibrisse
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 morbidly 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 congenitally, or at a very early age, often in
several children of the same family, where one of the parents has presented
it. 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 objects. 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 con-

13 Marshall, quoted by Youatt in his 16 This affection, as I hear from
work on Cattle, p. 284. Mr. Bowman, has been ably described
4 ¢Philosoph. Transact.,’ 1814, p. and spoken of as hereditary by Dr.

94.° Donders, of Utrecht, whose work was
‘5 “Medical Notes and Reflections, published in English by the Sydenham

3rd edit., p. 33. Society in 1864.

Cuap, XII. INHERITANCE. )

sequence of something like inflammation of the coats, under which they
yield, and there is ground for believing that it may often originate in
causes acting directly on the individual affected, and may thenceforward
become transmissible. 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 defects as have been
above mentioned; but the more primary and uncomplicated forms of it
are also sometimes in a marked degree transmitted in a family. Fourthly,
Cataract, or opacity of the crystalline 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 members 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; im 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.”

The following cases are taken from an able paper by Mr. W. Sedgwick,
and from Dr. Prosper Lucas.” Amaurosis, either congenital or coming on
late in life, and causing total blindness, is often inherited; it has been
observed in three successive generations. Congenital absence of the iris has
likewise been transmitted for three generations, a cleft-iris for four gene-
rations, being limited 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 owing to the
crystalline lens, with its capsule, slipping through an unusually 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 generations. 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 female
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 eye 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

17 Quoted by Mr. Herbert Spencer, Chirurg. Review,’ April, 1861, pp. 482-
‘ Principles of Biology,’ vol. i. p. 244, 6; ‘? Héréd. Nut.,’ tom. i. pp. 391-408,
18 * British and Foreign Medico-

10 INHERITANCE, CHAP, XII,

authority of Dr. Osborne,” the following curious instance of strong in-
heritance: 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 derived 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 inherited; this would not even follow

if both parents were affected by an anomaly which in most cases was
transmissible.

liven 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 care, and are highly valued. I
have consulted many works, and the unanimity 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 Huzard 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 doctrine “that there is scarcely a disease which does not
run in the stock, is gaining new advocates every day.” So it

19 Dr. Osborne, Pres. of Royal College land,’ vol. v. p. 511. ‘Encyclop. of

of Phys. in Ireland, published this case
in the ‘Dublin Medical Journal’ for
1835.

20 These various statements are taken
from the following works and papers ;—
Youatt on ‘The Horse, pp. 35, 220.
Lawrence, ‘ The Horse,’ p. 30. Karkeek,
in an excellent paper in ‘ Gard. Chro-
nicle,’ 1853, p. 92. Mr. Burke, in
‘Journal of R, Agricul. Soc. of Eng-

Rural Sports,’ p. 279. Girou de Buza-
reignues, ‘Philosoph. Phys.,’ p. 215.
See following papers in ‘The Veteri-
nary:’ Roberts, in vol. ii. p. 144; M.
Marrimpoey, vol. ii. p. 387; Mr. Kar-
eek, vol. iv. p. 5; Youatt on Goitre in
Dogs, vol. v. p. 483; Youatt in vol. vi.
pp. 66, 348, 412; M. Bernard, vol. xi.
p- 939; Dr. Samesreuther, on Cattle, in
vol. xii. p. 181; Percivall, in vol, xiii.

ing

Cuap. XII. INHERITANCE. 11

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.”

Seeing how hereditary evil qualities are, it is fortunate that
good health, vigour, and longevity are equally inherited. It
was formerly a well-known practice, when annuities were pur-
chased 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. As to the inheritance
of vigour and endurance, the English race-horse offers an
excellent instance. Hclipse begot 334, and 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 instances have ever occurred of such horses having won
a great race. ‘They are sometimes as fleet for short distances 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 horse saving his ‘distance’ in running two
miles with thoroughbred 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 ancestors. 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 Continent which has not some English race-blood
in his veins.”

With respect to the transmission of the many slight, but in-

p. 47. With respect to blindness in
horses, see also a whole row of authori-
ties in Dr. P. Lucas’s great work, tom.
i. p. 899. Mr. Baker, in ‘The Veteri-
nary, vol. xill. p. 721, gives a strong
case of hereditary imperfect vision and
of jibbing.

21 Knight on ‘The Culture of the
Apple and Pear,’ p. 34. Lindley’s
‘ Horticulture,’ p. 180.

22 These statements are taken from
the following works in order :—Youatt
on ‘The Horse,’ p. 48; Mr. Darvill, in
‘The Veterinary,’ vol. viii. p. 50. With
respect to Robson, see ‘ The Veterinary,’
vol. iii. p. 580; Mr. Lawrence on ‘ The
Horse,’ 1829, p. 9; ‘ The Stud Farm,’
by Cecil, 1851; Baron Cameronn,
quoted in ‘The Veterinary,’ vol. x, p.
500,

12 INHERITANCE. CnaP, XII,

finitely diversified characters, by which the domestic races of
animals and plants are distinguished, nothing need be said; for
the very existence of persistent races proclaims the power of
inheritance.

A few special cases, however, deserve some consideration. It
might have been anticipated, that deviations from the law of
symmetry would not have been inherited. But Anderson® states
that a rabbit produced in 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 account™ it appéars
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,” and she produced 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 the 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
asymmetrical 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 they are noticed here
chiefly on account of their occasional regrowth after amputation. Poly-
dactylism graduates* by multifarious steps from a mere cutaneous ap-
pendage, 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 vessels, is sometimes so perfect, that it escapes detec-
tion, unless the fingers are actually counted. Occasionally there are
several supernumerary digits; but usually only one, making the total
number six. This one may represent either a thumb or finger, being
attached 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

*3 “Recreations in Agriculture and 5 ‘Vrolik has discussed this point at
Nat. Hist.,’ vol. i. p. 68. full length in a work published in Dutch,
** «Ueber die EHigenschaften, &c. from which Mr. Paget has kindly trans-
1828, s. 107. lated for me passages. See, also, Isidore

»° Bronn’s ‘Geschichte der Natur, Geoffroy St. Hilaire’s ‘Hist. des Ano-
Band ii. s. 132. malies,’ 1832, tom. i. p. 684. ;

Cuap, XII. INHERITANCE. Ri.
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 shown a total of ninety-two hands and ninety-two feet
each with six digits. 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,” that the hands are not more frequently affected than
the feet.

The presence of more than five digits is a great anomaly, for this num-
ber is not normally exceeded by any mammal, bird, or existing reptile.®
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 married one similarly affected. In such cases
the child of the fifth generation would have only 1-82nd part of the blood
of his first sedigitated ancestor. Other cases are rendered remarkable
by the affection 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. Struthers gives the following
instance: in the first generation an additional digit appeared on one hand;
in the second, on both hands; in the third, three brothers had both hands,
and one of the brothers a foot affected ; and in the fourth generation all
four limbs were affected. Yet we must not over-estimate the force of
inheritance. 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 deviations of structure,
of a nature almost as anomalous as supernumerary 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 affected.”

7 «Edinburgh New Phil. Journal,’
July, 1863.

8 Some great anatomists, as Cuvier
and Meckel, believe that the tubercle
on one side of the hinder foot of the
tailless Batrachians represents a sixth
digit. Certainly, when the hinder foot
of a toad, as soon as it first sprouts
from the tadpole, is dissected, the par-
tially ossified cartilage of this tubercle
resembles under the microscope, in a
remarkable manner, a digit. But the
highest authority on such subjects,
Geeenbaur (Untersuchung zur ver-
gleich. anat. der Wirbelthiere: Carpus
et Tarsus, 1864, s. 63), concludes that

this resemblance is not real, only supers
ficial.

29 For these several statements, see
Dr. Struthers, in work cited, espe-
cially on intermissions in the line of
descent. Prof. Huxley, ‘ Lectures on
our Knowledge of Organic Nature,’
1863, p.97. With respect to inheritance,
see Dr. Prosper Lucas, ‘ L’ Hérédité Nat.,’
tom. i. p. 325. Isid. Geoffroy, ‘ Anom.,’
tom. i. p. 701. Sir A. Carlisle, in ‘ Phil,
Transact.,’ 1814, p. 94. A. Walker, on
‘Intermarriage, 1838, p. 140, gives a
case of five generations; as does Mr,
Sedewick, in ‘ Brit, and Foreign Medico-
Chirurg. Review,’ April, 1863, p. 462,

14 INHERITANCE. CHAP, XIT,

Additional digits have been observed in negroes as well as in other races
of man, and in several of the lower animals. Six toes have been described
on the hind feet of the newt (Salamandra cristata), 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 Sin
hyoidal apparatus, which is properly absorbed during the act of meta:
morphosis, 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.” With animals which have properly
less than five digits, the number is sometimes increased 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 legs
rudimentary state. Thus the dog has properly four toes behind, but in
the larger breeds a fifth toe is commonly, though not perfectly, deve-
loped. 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.

The most interesting point with respect to supernumerary digits is their
occasional regrowth after amputation. Mr. White® describes 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 men-
tions a case of partial regrowth of an additional thumb, amputated when
the child was three months old; and the late Dr. Falconer 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 sister 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 resided, 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.

On the inheritance of other anomalies in
the extremities, see Dr. H. Dobell, in vol.
xlvi. of ‘ Medico-Chirurg. Transactions,’
1863; also Mr. Sedgwick, in op. cit.,
April, 1868, p. 460. With respect to
additional digits in the negro, see
Prichard, ‘ Physical History of Man-
kind.’ Dr. Dieffenbach (‘ Journ. Royal
Geograph. Soc.,’? 1841, p. 208) says
this anomaly is not uncommon with the

Polynesians of the Chatham Islands.

30 “The Poultry Chronicle,’ 1854, p.
09,

31 The statements in this paragraph
are taken from Isidore Geoffroy St.
Hilaire, ‘Hist. des Anomalies, tom. i.
pp. 688-693.

®2 As quoted by Carpenter, ‘ Princ.
of Comp. Physiology,’ 1854, p. 480.

CHaP. XII,

INHERITANCE, 15

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 finger, 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 threo
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, including a bone; so that it will for the third time have to be

operated on.

Now 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. But
man in his embryonic condition has a considerable power of reproduc-
tion, for Sir J. Simpson * 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 nodules, on two of which small points of nails could be
detected ;” so that these nodules clearly represented fingers in process of
regrowth. 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 regrowth. Spallanzani 35
cut off the legs and tail of a salamander six times, and Bonnet eight
times, successively, and they were reproduced. An additional digit beyond
the proper number was occasionally formed after Bonnet had cut off or had
divided longitudinally the hand or foot, and in one instance three additional
digits were thus formed. 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 chapter, they pro-

bably present no real difference,

The larvee or tadpoles of the tailless

Batrachians, but not the adults,” are capable of reproducing lost
members.” 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-

*8 Miiller’s ‘Phys,’ Eng. translat., vol.
1., 1838, p. 407. A thrush, however, was
exhibited before the British Association
at Hull, in 1853, which had lost its
tarsus, and this member, it was asserted,
had been thrice reproduced : I presume
it was lost each time by disease.

%* “Monthly Journal of Medical
Science,’ Edinburgh, 1848, new series,
vol. ii. p. 890.

% “An Essay on Animal Reproduc-
tion,’ trans, by Dr. Matey, 1769, p. 79.

© Bonnet, ‘Ciuvres d’Hist, Nat.,’
tom. v., part i., 4to. edit., 1781, pp. 343,

350; 353,

37 So with insects, the larve re-
produce lost limbs, but, except in one
order, the mature insect has no such
power. But the Myriapoda, which ap-
parently represent the larvee of true in-
sects, have, as N ewport has shown, this
power until their last moult. See an
excellent discussion on this whole
subject by Dr. Carpenter in his ‘ Prine,
Comp. Phys., 1854, p. 479.

38 Dr. Giinther, in Owen’s ‘ Anatomy
of Vertebrates,’ vol. i, 1866, p. 567.
Spallanzani has made similar observa-
tions,

16 INHERITANCE. Crap, a

water fish are cut off, they are perfectly reproduced in about six weeks’
time.

From these several facts we may infer that supernumerary
digits in man retain to a certain extent an embryonic condi-
tion, 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 mammal, bird, existing reptile, or amphibian (unless
the tubercle on the hind feet of the toad and other taillegs
Batrachians be viewed as a digit) has more than five; whilst
fishes sometimes have in their pectoral fins 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.” °°

We encounter much difficulty in attempting to reduce these
various facts to any rule or law. The inconstant number of
the additional digits—their irregular attachment to either the
inner or outer margin of the hand—the gradation which can
be traced from a mere loose rudiment of a single digit to a
completely double hand—the occasional appearance of addi-
tional digits in the salamander after a limb has been ampu-
tated—these various facts appear to indicate mere fluctuating
monstrosity ; and this perhaps is all that cay be safely said.
Nevertheless, as supernumerary digits in the higher animals, from
their power of regrowth and from the number thus acquired
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
actual rudiment can be detected, yet that a latent tendency to
the formation of an additional digit exists in all mammals, in-
cluding man. On this view, as we shall more plainly see in the

49 «On the Anatomy of Vertebrates,’ 1866, p. 170: with respect to the pectoral
fins of fishes, pp. 166-168.

CuaP. XII. INHERITANCE, 17

next chapter when discussing latent tendencies, we should have
to look at the whole case as one of reversion to an enormously
remote, lowly-organised, and multidigitate progenitor.

I may here allude to a class of facts closely allied to, but
somewhat different from, ordinary cases of inheritance. Sir H.
Holland “ 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 years old; he also remarks that children of
the same family often exhibit in common infantile diseases the
same peculiar symptoms. My father mentioned to me the case
of four brothers who died between the ages of sixty and seventy,
in the same highly peculiar comatose state. An instance hag
already been given of supernumerary digits appearing in four
children out of six in a previously unaffected family. Dr.
Devay 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. Sedgwick ”
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 illustrate the
force of inheritance, but we must now consider cases, grouped as
well as the subject allows into classes, showing how feeble, capri-
cious, or deficient the power of inheritance sometimesis. When
a new peculiarity first appears, we can never predict whether it
will be inherited. If both parents from their birth present

40 “Medical Notes and Reflections,’ sanguins,’ 2nd edit., 1862, p. 103.

1839, pp. 24, 34, See, also, Dr, P. # «British and Foreign Medico-
Lucas, ‘1’Héréd. Nat.,’ tom. ii. p. 33, Chirurg. Review,’ July, 1863, pp. 183,
“1 «Du Danger deg Mariages Con- 189,
VOL. II. C

18 INHERITANCE,

Cuap, XII,

the same peculiarity, 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 seed-
lings. With most plants the power of transmission notoriously
depends on some innate capacity in the individual: thus Vj].
morin® raised from a peculiarly coloured balsam some seed-
lings, which all resembled their parent; but of these seedlings
some failed to transmit the new character, whilst others trans-
mitted it to all their descendants during several successive gene-
rations. 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 trees 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 borne 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 secd-
lings 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 weep-
ing character, in a greater or less degree, to all its seedlings; some of the
young oaks being so flexible that they have to be supported by props;
others not showing the weeping tendency till about twenty years old.“
Mr. Rivers fertilized, as he informs me, the flowers of a new Belgian
weeping thorn (Crategus 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. MacNab,* seedlings from a magnificent weepmg
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. Lastly, a weeping and almost
prostrate yew (Taxus baccata) was found in a hedge in Shropshire; it was
a male, but one branch bore female flowers, and produced. berries; these,

43 Verlot, ‘La Production des Variétés,’ 45 Verlot, ‘La Product. des Variétés,
1865, p. 82. 1865, p. 94. Eas

44 Toudon’s ‘Gard. Mag.,’ vol. xii., 46 Bronn’s ‘Geschichte der Natur,
1836, p. 368. b. iis, 121.

Cup. XII. INHERITANCE. 19

being sown, produced seventeen trees, all of which had exactly the same
peculiar habit with the parent-tree.”

These facts, it might have been thought, would have been sufficient
to render it probable that a pendulous habit would in all cases be
strictly inherited. But let us look to the other side, Mr. MacNab‘
sowed seeds of the weeping beech (Fagus sylvatica), but sueceeded in raising
only common beeches. . Mr. Rivers, at my request, raised a humber 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 above
twenty thousand seeds of the weeping ash (Fraxinus excelsior), and not a
single seedling was in the least degree pendulous: in Germany, M. Borch-
meyer raised a thousand seedlings, with the same result. Nevertheless,
Mr. Anderson, of the Chelsea Botanic Garden, by sowing seed from a weeping
ash, which was found before the year 1780, in Cambridgeshire, raised several
pendulous trees.” Professor Henslow also informs me that some seedlings
from a female weeping 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 (£. 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 weeping variety of the common ash, which has been extensively
propagated by buds during a long period, did not, with Mr. Rivers,
transmit its character 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, trans-
mitted to its seedlings the pendulous habit in excess!

Many analogous facts could be given, showing how apparently capricious
is the principle of inheritance. AJ] the seedlings from a variety of the Bar-
berry (B. vulgaris) with ved leaves inherited the same character ; only about
one-third of the seedlings of the copper Beech (agus sylvatica) had purple
leaves. Not one out of a hundred. seedlings of a variety of the Cerasus
padus, with yellow fruit, bore yellow fruit: one-twelfth of the seedlings of
the variety of Cornus mascula, with yellow fruit, came true : °° and lastly, all
the trees raised by my father from a yellow-berried holly (lex aquifolium),

47 Rev. W. A. Leighton, ‘Flora of Loudon’s ‘Gard. Magazine,’ vol. x,
Shropshire,’ p. 497; and Charlesworth’s 1834, pp. 408, 180; and vol. ix., 1833,
‘Mag. of Nat. Hist.,’ vol. i, 1837, p. _p. 597,

30. °° These statements are taken from

*8 Verlot, op. cit., p. 98. Alph. De Candolle, ‘ Bot. Géograph..,’
© For these several statements, see p. 1083,

c 2

20 INHERITANCE. pga

found wild, produced yellow berries. Vilmorin™ observed in a bed of
Saponaria calabrica an extremely dwarf variety, and raised from it a large
number of seedlings; some of these partially resembled their parent, ang
he selected their seed; but the grandchildren were not in the least dwarfed -
on the other hand, he observed 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
intermediate 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 an-
nuals come true: thus I purchased German seeds of thirty-four named
sub-varieties of one race of ten-week stocks (Matthiola annua), and raised
a hundred and forty plants, all of which, with the exception 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 exception. Again, I procured packets of German seed of twenty-
five named varieties of common and quilled asters, and raised a hundred
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 transmit their
colour much more truly than any other variety. This fact probably stands
in close relation with one observed by Verlot,” namely, that flowers which
are normally white rarely vary into any other colour. I have found that
the white varieties of Delphiniwm consolida and of the Stock are the truest.
It is, indeed, sufficient to look through a nurseryman’s seed-list, to see the
large number of white varieties which can be propagated by seed. The
several coloured varieties of the sweet-pea (Lathyrus odoratus) are very
true; but I hear from Mr. Masters, of Canterbury, who has particularly
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 ;” 68 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,
¢hat this occurs under cultivation, and therefore under changed conditions.

With many flowers, especially perennials, nothing can be more fluctuating
than the colour of the seedlings, as is notoriously the case with verbenas,
carnations, dahlias, cinerarias, and others. I sowed seed of twelve

51 Verlot, op. cit., p. 38. 54 See ‘Cottage Gardener,’ April fe
22 Op. cit., p. 59. 1860, p. 18, and Sept. 10, 1861, p. #9?
53 Alp. De Candolle, ‘Geograph. - ‘Gard. Chron.,’ 1845, p. 102.

Bot.,’ p. 1082.

Cuap. XII. INHERITANCE. 21

named varieties of Snapdragon (Antirrhinum majus), and utter confusion
was the result. In most cases the extremely 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 veris and
vulgaris), from their reciprocally dimorphic structure; 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, fer-
tilised by Mr. J. Scott with its own pollen, and eighteen came up purple ot
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, 72 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 cul-
tivation in the same soil, by long-continued selection, and especially by the
prevention of crosses. I infer this from certain annual larkspurs (Delphi-
nium consolida and ajacis), of which common seedlings present a greater
diversity of colour than any other plant known to me; yet on procuring
seed of five named German varicties of D. consolida, only nine plants out of
ninety-four were false; and the seedlings of six varieties of D. ajacis were
true in the same manner and degree as with the stocks above described. A
distinguished botanist maintains that the annual species of Delphinium are
always self-fertilised ; therefore I may mention that thirty-two flowers
on a branch of D. consolida, enclosed in a net, yielded twenty-seven capsules,
with an average of 17:2 seed in each; whilst five flowers, under the same
net, which were artificially fertilised, in the same manner ag must be
effected by bees during their incessant visits, yielded five capsules with an
average of 85°2 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 carna-
tions, &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: Autenrieth and Ammon assert that, after two generations,
colts of a uniform colour are produced with certainty.**

Tn 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-

6 Darwin, in ‘ Journal of Proc, Linn, Soe. Bot., 1862, p. 94.
56 Hofacker, ‘ Ueber die Higenschaften,’ &., s. 10.

44 INHERITANCE. Cuap, XI]

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 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 Sebright Bantams,
says °* that, “ why this should be so, I know not, but I am con-
fident 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 sufficiently 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,
when 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 parents
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. Sedgwick,® in commenting on
this remarkable and fortunate failure in the power of trans-
mission in the direct line, remarks 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

57 Bechstein, ‘Naturgesch. Deutsch- Tegetmeier, 1866, p. 245.
lands,’ b. iv. s. 462. Mr. Brent, a great °° * British and Foreign Med.-Chirurs:
breeder of canaries, informs me that Review, July, 1861, pp. 200-204. Mr.
he believes that these statements are Sedgwick has given such full details ch
correct. this subject, with ample references, tha
58 «The Poultry Book, by W. B. I need refer to no other authorities.

Cap. XI. INHERITANCE, 23

definite conclusion. In some cases mutilations have been prac-
tised for a vast number of generations without any inherited result.
Godron has remarked that different 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 various
parts of their bodies, and there is no reason whatever 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
inherited effect ; Blumenbach, on the other hand, asserts that
in Germany Jews are often born in a condition rendering cir-
cumcision 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 pro-
duce 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, &., 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 hag 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 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 hig sons had the same finger on the same
hand similarly crooked. <A soldier, fifteen years before his
marriage, lost his left eye from purulent ophthalmia, and his

60 ¢ De PEspece,’ tom. ii., 1859, p. 299.
61 ¢ Philosoph, Magazine, vol. iv., 1799, p. Dd.

24 INHERITANCE. Cuap., XII,

two sons were microphthalmic on the same side.” 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 enormous. But perhaps the most
remarkable and trustworthy fact is that given by Dr. Brown-
Séquard,® namely, 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 convulsive disease like epilepsy: and it should be especially
noted that this eminent physiologist bred a large number of
euinea-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 muti-
lations, especially when followed by disease, or perhaps exclu-
sively when thus followed, are occasionally inherited.

Although many congenital monstrosities are inherited, 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, yet other malformations are rarely or never inherited.
Of these latter cases, many are probably due to injuries in the
womb or egg, and would come under the head of non-inherited
injuries or mutilations. With plants, a long catalogue of in-
herited monstrosities 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 intelligible on
the principle, that a strong tendency to inheritance does exist, but

® This last case is quoted by Mr. by Mr. Baker in ‘The Veterinary,’ vol.
Sedgwick in ‘British and Foreign xiii. p. 723. Another curious case is
Medico-Chirurg. Review, April, 1861, given in the ‘ Annales des Science. Nat.,’
p. 484. For Blumenbach, see above- 1st series, tom. xi. p. 324.
cited paper. See, also, Dr. P. Lucas, & <Proc. Royal Soc,’ vol. x. p-
‘Traité de ’Héréd. Nat.,’ tom. ii. p. 297.
492. Also ‘Transact. Linn. Soc.,’ vol. 64 Mr. Sproule, in ‘British Medical
ix. p. 323, Some curious cases are given Journal,’ April 18, 1863.

7

i eee ine eee

Cuap. XII. INHERITANCE, 25

that it is overborne by hostile or unfavourable conditions of life.
No one would expect that our improved pigs, if forced during
several generations 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 generations.
There seems also to be a close relation between certain peculiar
pastures and the inheritance of an enlarged 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 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, whilst common ducks, kept in the same yard
and treated in the same manner, did not hateh 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 con-
ditions of life continually inducing fresh variability. We have
seen that when the seeds of pears, plums, apples, &c., are sown,
the seedlings generally inherit some degree of family likeness
irom the parent-variety. Mingled with these seedlings, a few,
and sometimes many, worthless, wild-looking plants commonly
appear; and their appearance may be attributed to the prin-
ciple of reversion. But scarcely a single seedling will be found

26 INHERITANCE. Cnap, XII

perfectly to resemble the parent-form; and this, I believe,
may be accounted for by constantly recurring variability in-
duced by the conditions of life. I believe in this, because jt
has been observed that certain fruit-trees truly propagate their
kind whilst growing on their own roots, but when prafted on
other stocks, and by this process their natural state is mani-
festly affected, they produce seedlings which vary greatly, de-
parting from the parental type in many characters. 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 new conditions, they ceased to be
variable,—that is, they became amenable to the power of in-
heritance. Nearly all the plants which cannot be propagated
with any approach to certainty by seed, are kinds: which have
long been propagated 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 transmitting 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 prepotency.

Conclusion.

It has, I think, been shown in the early part of this chapter
how strongly new characters of the most diversified 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

® Downing, ‘Fruits of America,’ p. 5; Sageret, ‘Pom. Phys.,’ pp. 43, 72.

Cuap, XII. INHERITANCE. 27

anomalies have been transmitted. But the power of transmission
is extremely variable: in a number of individuals descended
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 injuries 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 cer-
tainly inherited. Even those characters which are considered
the most fluctuating, such as colour, are with rare exceptions
transmitted much more forcibly than is generally supposed. The
wonder, indeed, in all cases is not that any character should
be transmitted, but that the power of inheritance should ever
fail. The checks to inheritance, as far as we know them, are,
firstly, circumstances hostile to the particular character in ques-
tion; 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 immediate parents.

This latter subject will be fully discussed in the following
chapter.

Ga INHERITANCE,

CHAPTER XIII.

*

|
|
|

INHERITANCE continued — REVERSION OR ATAVISM.

DIFFERENT FORMS OF REVERSION — IN PURE OR UNCROSSED BREEDS, AS IN PIGEONS,
FOWLS, HORNLESS CATTLE AND SHEEP, IN CULTIVATED PLANTS — REVERSION IN
FERAL ANIMALS AND PLANTS — REVERSION IN CROSSED VARIETIES AND SPECIES —
REVERSION THROUGH BUD-PROPAGATION, AND BY SEGMENTS IN THE SAME FLOWER
OR FRUIT — IN DIFFERENT PARTS OF THE BODY IN THE SAME ANIMAL — THE
ACT OF CROSSING A DIRECT CAUSE OF REVERSION, VARIOUS CASES OF, WITH
INSTINCTS — OTHER PROXIMATE CAUSES OF REVERSION — LATENT CHARACTERS

—— SECONDARY SEXUAL CHARACTERS — UNEQUAL DEVELOPMENT OF THE TWO
SIDES OF THE BODY — APPEARANCE WITH ADVANCING AGE OF CHARACTERS DERIVED
FROM A CROSS — THE GERM WITH ALL ITS LATENT CHARACTERS A WONDERFUL
OBJECT —- MONSTROSITIES — PELORIC FLOWERS DUE IN SOME CASES TO REVERSION.

THE great principle of inheritance to be discussed in this
chapter has been recognised by agriculturists and authors of
various nations, as shown by the scientific term Atavism, derived
from atavus, an ancestor; by the English terms of Reversion, or
Throwing back; by the French Pas-en-arritre ; and by the
German Liick-schlag, or Riick-schritt. When the child resembles
either grandparent more closely than its immediate parents, our
attention 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,—we feel a just degree of astonish-
ment. When one parent alone displays 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 characterised, and the child does 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

ae ETP ll

Cap. XII. REVERSION. 29

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 erandsire.

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 generation. Perhaps even a
fourth class might be instituted, to include reversions by seg-
ments 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.

Lieversion to lost Characters by pure or unerossed forms.—
Striking instances of this first class of cases were given in the
sixth chapter, namely, of the occasional reappearance, in variousl y-
coloured pure breeds of the pigeon, of blue birds with all the
marks which characterise the wild Columbia livia. Similar cases
were given in the case of the fowl. With the common ass, aS we
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
will here pass them over,

The aboriginal species from which our domesticated cattle and
sheep are descended, no doubt possessed horns ; but several horn-
less breeds are now well established. Yet in these—for instance,

30 INHERITANCE, CHAP, XII

in Southdown sheep—* it is not unusual to find among the male
lambs some with small horns.” The horns, which thus occa.
sionally 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?

There is reason to believe that sheep in their early domesti-
cated condition were “brown or dingy black;” but even in
the time of David certain flocks were spoken of as white ag
snow. During the classical period the sheep of Spain are de-
scribed by several ancient authors as being black, red, or tawny
At the present day, notwithstanding the great care which is
taken to prevent it, particoloured lambs and some entirely
black are Occasionally dropped by our most highly improved
and valued 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 scrupulous care; yet occasionally
erey-faced, or black-spotted, or wholly black lambs appear.‘ This
occurs still more frequently with the less improved breeds, such
as the Norfolks.® 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. W. 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 pro-
duce black lambs: he has gone on recrossing these crossed
sheep with pure white Leicesters during three successive gene-

1 Youatt on Sheep, pp. 20, 234. The 4 T have been informed of this fact
same fact of loose horns occasionally through the Rev. W. D. Fox, on the
appearing in hornless breeds has been accalieth authority of Mr. Wilmot : 8¢é,
observed in Germany: Bechstein, also, remarks on this subject in al
‘Naturgesch. Deutschlands,’ b. i. s. 362. original article in the ‘Quarterly

2 Youatt on Cattle, pp. 155, 174. ray 1849, p. 395.

3 Youatt on Sheep, 1838, pp. 17, 145, 5 Youatt, pp. 19, 234.

LEE

Cuap. XIII. REVERSION. dl

rations, 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. Hewitt® states that
chickens bred from some Rumpless fowls, which were reckoned
so good that they won a prize at an exhibition, “in a consider-
able number of instances were furnished with fully developed
tail-feathers.” On inquiry, the original breeder of these fowls
stated that, from the time when he had first kept them, they
had often produced 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 cultivated varieties of
Heartsease (Viola tricolor), plants perfectly wild both in their
foliage and their flowers are frequently produced ;”7 but the
reversion in this instance is not to a very ancient period, for the
best existing varieties of the heartsease are of comparatively
modern origin. 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 turnip’ 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 generations, most of our
cultivated plants could probably be brought back, without any
great change in their conditions of life, to a wild or nearly wild
condition: Mr. Buckman has effected this with the parsnip ;°

° «The Poultry Book,’ by Mr, Teget-

perience on this subject, has likewise
meier, 1866, p. 231.

assured me that this sometimes occurs,

7 Loudon’s ‘Gard. Mag.,’ vol. x., 1834, 8 ‘Gardener’s Chron..,’ 1855, p. 777.
p. 896: a nurseryman, with much ex- ® Tbid., 1862, p. 721.

32 INHERITANCE, Cnap, XII

and Mr. Hewett C. Watson, as he informs me, selected, during
three generations, “the most diverging plants of Scotch kaj]
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.”

Reversion in Animals and Plants which have run wild.—tn
the cases hitherto considered, the reverting animals 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 manner by various authors, that feral
animals and plants invariably return to their primitive specific
type. It is curious 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 do not know the aboriginal
parent-species, and cannot possibly tell whether 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 obliterate their proper character. Our domesticated
animals and plants, when they run wild, must always be exposed
to new conditions of life, for, as Mr. Wallace” has well remarked,
they have to obtain their own food, and are exposed to com-
petition 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.

10 See some excellent remarks on this subject by Mr. Wallace, ‘ Journal Proc.
Linn. Soc.,’ 1858, vol. iii. p. 60.

|

OuaP. XIII. REVERSION, 33

I will briefly run through the recorded cases. With neither horses nor
cattle is the primitive stock known; and it -has been shown in former
chapters that they have assumed different colours in different countries,
Thus the horses which have run wild in South America are generally
brownish-bay, 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 coun-
tries have hardly anywhere assumed a uniform character; but they are
probably descended from several domestic races, and aboriginally from
_ several 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-coloured tame rabbits are turned out in Europe, they
generally reacquire the colouring 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 suffer 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 J amaica, and
especially of Porto Santo, have assumed new colours and other new cha-

racters. ‘The best known case of reversion, and that on which the widely-
- spread belief in its universality apparently rests, is that of pigs. 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 longi-
tudinal 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 pig™ 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,” it is not
known what variety was first turned out, nor what character the feral
birds have assumed. The guinea-fowl in the West Indies, when feral,
seems to vary more than in the domesticated state.

With respect to plants run wild, Dr. Hooker ™ has strongly insisted on «
what slight evidence the common belief in their power of reversion rests.
Godron™ describes wild turnips, carrots, and celery; but these plants in
their cultivated state hardly differ from their wild prototypes, except in the

2 Capt. W. Allen, in his ‘Expedition
to the Niger,’ states that fowls have run
wild on the island of Annobon, and
have become modified in form and voice,
The, account is so meagre and vague

VOL. II.

that it did not appear to me worth
copying; but I now find that Dureau
de la Malle (‘Comptes Rendus, tom.
xli., 1855, p. 690) advances this as a
good instance of reversion to the primi-
tive stock, and as confirmatory of a
still more vague statement in classical
times by Varro.

13 «Flora of Australia, 1859, Intro-
duct., p. ix.

M4 «Del Espece,’ tom. ii. pp. 54, 58, 60.

D

34 ' INHERITANCE. Cuap. XII.

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 cultivated plant has run wild on so enormous a scale ag the
cardoon (Cynara cardunculus) 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 dered from a Cross, in the case of
Sub-varieties, Races, and Species.—When an individual having
some recognizable peculiarity unites with another of the same
sub-variety, not having the peculiarity in question, it often
reappears in the descendants after an interval of several gene-
rations. Every one must have noticed, or heard from old people
of children closely resembling in appearance or mental dis-
position, 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,®

of which instances have been given in the last chapter, have
come into a family from one parent, and have reappeared
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 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 per-
mitted 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 pointer-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 expres
sion, he had only 1-16th of her blood in his veins. Here it cab
hardly be doubted that a character derived from a cross with
an individual of the same variety reappeared after passing over
three generations.

_ Mr. Sedgwick gives many instances in the ‘British and Foreign Med.-
Chirurg. Review, April and July, 1863, pp. 448, 188.

Crap. XIII. REVERSION, 3O

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 generations. I have myself
seen the clearest evidence of this in crossed pigeons and with
various ‘plants. Mr. Sidney states that, in a litter of Essex
pigs, two young ones appeared 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
farmyard at Betley Hall some fowls showing a strong likeness
to the Malay breed, and was told by Mr. Tollet 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 generations after a
single cross, either with a distinct breed or merely with an
inferior animal, the breed may be considered as

pure, and free
from all danger of reversion.

No one supposes that less than
three generations suffices, and most breeders think that SIX,

seven, or eight are necessary, and some go to still greater
lengths.” But neither in the case of a breed which has been
contaminated by a single cross, nor when, in th
an intermediate breed, half-bred animals

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 beth parents, but lost at some former period, re-

appear ; for such characters may recur after an almost indefinite
number of generations,

e attempt to form
have been matched

© In his edit. of ‘ Youatt on the Pig,’ article on the subject in ‘Gard. Chro-
1860, p. 27.

: ee nicle,’ 1856, p. 620. I could add a vast
cs * Dr. P. Lucas, ‘Héréd, Nat. tom, number of references, but they would
ll, pp. 314, 892: see a good practical be superfluous.

weZ

36 INHERITANCE. Cuap, XIII,

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 instances, for in the
case of plants almost every one who has worked on this subject
from the time of Kélreuter to the present day has insisted on this
tendency. Girtner has recorded some good instances; but no
one has given more striking cases than Naudin.® The ten-
dency differs in degree or strength in different groups, and
partly depends, as we shall presently see, on the fact of the
parent-plants having been long cultivated. Although the ten-

dency to reversion 1s extremely general with nearly all mongrels -

and hybrids, it cannot be considered as invariably charac-
teristic of them; there is, also, reason to believe that it may
be mastered by long-continued selection; 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 reap-
pearance 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 endowed with prepotency of trans-
mission. In some few cases the power of reversion wholly fails,
without our being 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.” ®

Reversion through Bud-propagation—Partial Reversion, by seg-
ments in the same flower or fruit, or in different parts of the

18 Kélreuter gives cases in his ‘Dritte p. 485. Dr. H. Dobell, in ‘Med~-
Fortsetzung, 1766, s. 53,59; andinhis Chirurg. Transactions,’ vol. xlvi., gives
well-known ‘Memoirs on Lavatera and an analogous case, in which, in a large
Jalapa.’ Gartner, ‘ Bastarderzeugung,’ family, fingers with thickened joints
s. 437, 441, &c. Naudin, in his were transmitted to several members
‘Recherches sur l’Hybridité, Nouvelles during five generations; but when the
Archives du Muséum,’ tom. i. p. 25. blemish once disappeared it never 1

19 Quoted by Mr. Sedgwick in appeared.

‘ Med.-Chirurg. Review, April, 1861,

CuaP, XIII. REVERSION. 37

body in the same individual animal—tIn 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,
reassumed their former character; and here we have with buds
reversion by segments. Vilmorin® has also recorded several
cases with plants derived from seed, of flowers 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 propagated for a length of time by seed, striped
seedlings occasionally 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
Naudin” 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, apparently result
from certain characters not readily blending together, and, as
a consequence of this incapacity for fusion, 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 intermediate in character, but with ad-
vancing age revert wholly or by segments to either parent-
form, or to both. Thus young trees of the Cytisus adamt 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

© Verlot, ‘Des Variétés,’ 1865, p. 63,

*! “Nouvelles Archives du Muséum,’ 315)
tom. i, p. 25. Alex. Braun (in hig

‘Rejuvenescence, Ray Soc., 1853, p.
apparently holds a_ similar
opinion.

38

INHERITANCE.

Cuap. XIII,

in crossed plants of Tropzolum, Cereus, Datura, and Lathyrus

are all analogous. As, however, these plants are hybrids of
the first generation, and as their buds 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
plant, they may be thus included.

Analogous facts have been observed in the animal kingdom,
and are more remarkable, as they occur strictly 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 crossed several white hens with a black cock, and

many of the chickens were during the first year perfectly white,

Same

but acquired during the second year black feathers; on the ~

other hand, some of the chickens which were at first black
became during the second year piebald with white. A great
breeder” says, that a Pencilled Brahma hen which has any of
the blood of the Light Brahma in her, will “ occasionally pro-
duce 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 remarkable fact: I

crossed a turbit, which has a frill formed by the feathers being

reversed on its breast, with a trumpeter ; and one of the young

pigeons 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,® calves produced

from a red cow by a black bull, or from a black cow by @

red 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 previous or some

*2 Mr. Teebay, in ‘ The Poultry Book,’ by Mr. Tegetmeier,’ 1866, p. 72.
*8 Quoted by Hofacker, ‘ Ueber die Higenschiiften,’ &., s. 98.

‘Cua, XII. REVERSION. 39

former generation; but in the following cases the characters
which thus reappear formerly appertained to the species, and
were lost at a more or less remote epoch. ‘Thus, according
to Azara,* the calves of a hornless race of cattle which originated
in Corrientes, though at first quite hornless, as they become
adult, sometimes acquire small, crooked, and loose horns; and
these in succeeding years occasionally become attached to the
skull. White and black bantams, both of which generally 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 certain 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
hackles.” Now, as Gallus bankiva is coloured red and orange,
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 plumage 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—lIt has long been
notorious that hybrids and mongrels often revert to both or to one
of their parent-forms, after an interval of from two to seven or
-eight, or according to some authorities even a greater number
of generations. But that the act of crossing in itself gives an
impulse towards reversion, as shown by the reappearance of
long-lost characters, has never, I believe, been hitherto proved.
The proof lies in certain peculiarities, which do not characterise
the immediate parents, and therefore cannot have been derived
from them, frequently appearing in the offspring of two breeds
when crossed, which peculiarities never appear, or appear with
extreme rarity, in these same. breeds, as long as they are pre-

4 ‘Hgsais Hist. Nat. du Paraguay; Poultry Book, by Mr. Tegetmeier, 1866,
tom. ii., 1801, p. 372. p. 248.

» These facts are given on the high 26 «The Poultry Book,’ by Tegetmeier,
authority of Mr. Hewitt, in ‘The 1866, p. 97.

eee ne Ne

40 INHERITANOR, Guar, XI

cluded from crossing. As this conclusion seems to me hi

hl
curious and novel, I will give the evidence in detail. ri

My attention was first called to this subject, and I was led to make
numerous experiments, by MM. Boitard and Corbié having stated that
when they crossed certain breeds, pigeons coloured like the -wild 0: Viviee
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 described 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 recrossed,

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 dis-
tinguishable 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 C. livia would have been
almost a prodigy. 3

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 offspring of a black
Spanish cock and white Silk hen, was coloured almost exactly like the
wild Gallus bankiva. 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 without the appearance of a red feather,
The fact, given on the authority 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 pro-
genitor 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 between the common fowl and a very distinct species, the Gallus
varius; 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. boschas). Of the musk-duck (A. moschata, 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 Himalaya
rabbit, with its snow-white body, black ears, nose, tail, and feet, breeds

Cuap. XII. REVERSION, 41

perfectly true. This race is known to have been formed by the union of
two varieties of silver-grey rabbits. Now, when a Himalayan doe was
crossed by a sandy-coloured buck, a silver-grey rabbit 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 subsequently; but occasionally young
Himalayan rabbits are. born of a light silver-grey, which colour soon dis-
appears; so that here we have a trace of reversion, during an early period
of life, to the parent-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,”
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 toa light or yellow shade.
But a considerable number of the offspring—and Mr. Beasley calls atten-
tion to this as a remarkable fact—were white, or white with red ears.
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 domesticated animals. Now there is some reason to
believe* 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.

In 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 strongly 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 teniopus of Abyssinia,” 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

ie ‘ Gardener's Chron. and Agricultural Gazette,’ 1866, p. 528.
*8 Ibid., 1860, p. 343. *® Sclater, in ‘Proc. Zoolog. Soc.,’ 1862, p. 163.

42, : INHERITANCE, Cuap, XIII.

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 evidence 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, 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, and remarks, that mules
are particularly liable to be thus striped on their legs. In South America,
according to Roulin,* such stripes are more frequent and conspicuous in
the mule than in the ass. In the United States, Mr. Gosse,” 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 appears from the .

figures given in Dr. Gray’s ‘ Knowsley Gleanings,’ and still more plainly
from that given by Geoffroy and F. Cuvier,* 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,* from a chesnut, nearly 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 subse-
quently 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

30 ‘ History of the Horse,’ p. 212. 84 <Philosoph. Transact.,’ 1821, Pp. 20.
31 ¢Mém. présentés par divers Savans % Sclater, in, ‘Proc. Zoolog. Soe.,
2% VAcad, Royale, tom. vi. 1835, p. 1862, p. 163: this species is the Ghor-
338. Khur of N.W. India, and has often
82 < Letters from. Alabama, 1859, p. been called the Hemionus of Pallas.
280. See, also, Mr. Blyth’s excellent paper @

33 ‘ Hist, Nat, des Mammiferes, 1820, ‘Journ. of Asiatic Soc. of Bengal, vol.
tom. i, Xxviii., 1860, p. 229,

Cuar. XU. REVERSION, f 43

or leg stripes; but traces of these latter stripes may occasionally be seen
even in the adult; and Colonel S. Poole, who has had ample oppor-
tunities 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 Knowsley® from a female of
this species by a male domestic ass, had all four legs transversely and. con-
spicuously 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 several equine
species tends in a marked manner to cause stripes to appear
on various parts of the body, especially on the legs. As we do
not know whether the primordial 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 re-
appearing by reversion in crosséd pigeons, fowls, ducks, &e., will
come to the same conclusion with respect to the horse-genus;
and in this case we must admit that the progenitor of the group
was striped on the legs, shoulders, face, and probably over the
whole body, like a zebra. If ‘we reject this view, the frequent
and almost regular appearance of stripes in the several fore-
going 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 to incubate that I have seen notices pub-
lished in works on poultry, when hens of such breeds have
taken to sit. Yet the aboriginal species was of course a good
incubator; for with birds in a state of nature hardly any

Col. Hamilton Smith, in ‘Nat. Library,
Horses,’ p. 318; and ‘ Dict. Class. d’Hist.

© Another species of wild ass, the
true A. hemionus or Kiang, which

ordinarily has no shoulder-stripes, is
said occasionally to have them; and
these, as with the horse and ags, are
sometimes double: see Mr. Blyth, in
the paper just quoted, and in ‘Indian
Sporting Review,’ 1856, p. 320; and

Nat.,’ tom. iii. p. 563.
7 Figured in the ‘ Gleanings from the
Knowsley Menageries,’ by Dr.J.E.Gray.
38 Cases of both Spanish and Polish
hens sitting are given in the ‘ Poultry
Chronicle,’ 1855, vol. iii. p. 477,

44 INHERITANCE. Cuap, XIII,

instinct 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 sitters, that the re-
appearance of this instinct must be attributed to reversion from
crossing. One author goes so far as to say, “that a crogg
between two non-sitting varieties almost invariably produces a
mongrel that becomes broody, and sits with remarkable steadi-
ness.”*® 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 instinct, any more
than that crossed fowls or pigeons invariably 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 appeared to afford a well-marked exception to
the foregoing rule ; but one of these hens, the only one which
was preserved, in the third year sat well on her eggs and 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 plumage 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 domesticated
species is crossed with a distinct species, whether this is a
domesticated or only tamed animal, the hybrids are often wild

39 <The Poultry Book,’ by Mr. Teget- Polish fowls, are “good and_ steady
meier, 1866, pp. 119, 163. The author, _ birds to sit.” Mr. B. P. Brent informs
who remarks on the two negatives me that he raised some good sitting
(‘ Journ, of Hort.,’ 1862, p. 325), states hens by crossing Pencilled Hamburgh
that two broods were raised from a and Polish breeds. A cross-bred bird
Spanish cock and Silver-pencilled Ham- froma Spanish non-incubating cock and
burgh hen, neither of which are incu- Cochin incubating hen is mentioned In
bators, and no less than seven out of — the ‘ Poultry Chronicle,’ vol. iii. p. 13,48
eight hens in these two broods “showed an “ exemplary mother.” On the other
a perfect obstinacy in sitting.” The hand, an exceptional case is given In the
Rey. E. 8. Dixon (‘Ornamental Poultry,’ ‘Cottage Gardener, 1860, p.388, ofa hen
1848, p. 200) says that chickens reared raised from a Spanish cock and black
from a cross between Golden and Black Polish hen which did not incubate.

_

|
|

Cap. XIII. REVERSION. 45

to such a degree, that the fact is intelligible only on the prin-
ciple that the cross has caused a partial return to the primitive
disposition.

The Earl of Powis formerly imported some thoroughly domes-
ticated humped cattle from India, and crossed them with English
breeds, which belong to a distinct species; and his agent re-
marked to me, without any question having been asked, how oddly
wild the cross-bred animals were. The European wild boar and
the Chinese domesticated 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,
were “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 ;”“ but I have myself seen one exception to this rule.
Mr. 8. J. Salter,“ who raised a large number of hybrids from
a bantam-hen by Gallus Sonneratii, states that “all were
exceedingly wild.” Mr. Waterton® bred some wild ducks from
eges hatched under a common duck, and the young were
allowed to cross freely both amongst themselves 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 ags 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 remarkably wild. Hybrids are often
raised between the common and musk duck, and I have been
assured by three persons, who have kept these crossed birds,
that they were not wilds but Mr. Garnett* observed that his
female hybrids exhibited “migratory propensities,” of which
there is not a vestige in the common or musk duck, No case is

40 «The Poultry Book,’ by Teget- 42 ¢Hssays on Natural History,’ p,
meier, 1866, pp. 165, 167. 197,
41 ‘Natural History Review, 1863, 48 As stated by Mr. Orton, in hig

April, p. 277. ‘Physiology of Breeding,’ p, 12,

46 INHERITANCE.

Cup. XIII,

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 districts where large lakes and fens abound. Neyer.
theless, a large number of cases have been recorded“ 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 frequently
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 inhabitants of the island of Chiloe, who consist
of Indians commingled 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.” Livingstone,—and a more unimpeachable authority
cannot be quoted,—after speaking of a half-caste man on the
Zambesi, described by the Portuguese as a rare monster of
inhumanity, 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 remarked
to Livingstone, “God made white men, and God made black
men, but the Devil made half-castes.”“° When two races, both

44 M. E. de Selys-Longchamps refers (‘Ornitholog. Biography,’ vol. iii. P-
(‘ Bulletin Acad. Roy. de. Bruxelles, 168), speaking of these hybrids, says
tom. xii. No. 10) to more than seven of that, in North America, they “now
these hybrids shot in Switzerland and and then wander off and become quite
France. M. Deby asserts (‘ Zoologist,’ wild.”
vol. v., 1845-46, p. 1254) that several 45 ‘ Journal of Researches, 1845, p. 71:
have been shot in various parts of 46 «Expedition to the Zambesi, 1869,
Belgiumand NorthernFrance. Audubon pp, 25, 150,

Cap, XIII. REVERSION, 47

low in the scale, are crossed, the progeny seems to be emi-
nently 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 disposi-
tion of Zambos, or half-castes between Indians and Negroes;
and this conclusion has been arrived at by various observers.“
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.

Summary on the provimate causes leading to Reversion.—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 cultivated heartsease with large and
rounded flowers produces 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 domes-
ticated 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,
we can only say that changed habits of life apparently have
favoured a tendency, inherent or latent in the species, 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 and seeds receive. The posi-
tion, also, of buds, either on branches or on roots, sometimes
determines, as was formerly shown, the transmission of the

% Dr. P. Broca, on ‘ Hybridity in the Genus Homo,’ Eng. translat., 1864, p. 39.

48 INHERITANCE. Cuap. XIII.

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 re-
appearance in the offspring of long-lost characters, possessed by
neither parent nor immediate progenitor. When two white, or
red, or black pigeons, of well-established breeds, are united, the
offspring are almost sure to inherit the same colours; but when
differently-coloured birds are crossed, the opposed forces of
inheritance apparently 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. Indicus 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 cha-
racters proper to either pure parent-form. As a general rule,
crossed offspring in the first generation are nearly intermediate
between their parents, but the grandchildren and succeeding
generations continually revert, in a greater or lesser degree,
to one or both of their progenitors. Several authors have main-
tained that hybrids and mongrels include all the characters of
both parents, not fused together, but merely mingled in different
proportions in different parts of the body; or, as Naudin® has
expressed it, a hybrid is a living mosaic-work, in which the eye
cannot distinguish the discordant elements, so completely are
they intermingled. Wecan 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
vr fruit, by a process of self-attraction or self-affinity ; this
segregation taking place either by seminal or by bud-propagation.
Naudin further believes that the segregation of the two specific
elements or essences is eminently liable to occur in the male
and female reproductive matter; and he thus explains the almost

45 ‘Nouvelles Archives du Muséum,’ tom, i. p. 151.

Cuap. XIII. REVERSION, 49

universal tendency to reversion in successive hybrid generations.
For this would 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 Species, the
intermediate or hybrid state would still be retained, and there
would be no reversion. But it would, as I suspect, be more
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, ag 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 occasion-
ally yield an individual 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,

Giirtner 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 observer, but this con-
clusion 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 directly contradicted by Naudin’s observations,
and by the notorious fact that perfectly fertile mongrels exhi-
bit the tendency in a high degree,—even in a higher degree,
according to Giirtner himself, than hybrids.”

Gartner further states that reversions rarely occur with

49 ¢ Bastarderzeugung,’ 8. 582, 438, &e,

VOL. II. E

50 INHERITANCE, CHap, XIT

hybrid plants raised from species which have not been cultivated,
whilst, with those which have been long cultivated, they are of
frequent occurrence. This conclusion explains a curious dis.
crepancy: Max Wichura,® who worked exclusively on willows,
which had not been subjected to culture, never saw an in-
stance of reversion; and he goes so far as to suspect that the
careful Girtner 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 cultivated
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 leading 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 dis.
turbed, 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
crossed 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
cultivation, 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 or bud 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 ancestor 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 grandparents, 0
more remote ancestors. But this view is hardly conceivable.
If, however, we suppose that every character is derived exclu-

50 ‘Die Bastardbefruchtung .... der Weiden,’ 1865, 8, 23. For Gartner's
remarks on this head, see ‘ Bastarderzeugung,’ s. 474, 582.

Cuar. XIII. REVERSION, 51

‘sively from the father or mother, but that many characters lie
latent in both parents during a long succession of generations,
the foregoing facts are intelligible. In what manner characters
may be conceived 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 illustration is
afforded by secondary sexual characters. In every female all
the secondary male characters, and in every male all the secondary
female characters, apparently exist in a latent state, ready to
be evolved under certain conditions. It is well known that a
large number of female birds, such as fowls, various pheasants,
partridges, peahens, ducks, &c., when old or diseased, or when
operated on, partly assume the secondary male characters 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.’ A duck ten years old has been known to
assume both the perfect winter and summer plumage of the
drake.” Waterton® gives a curious case of a hen which had
ceased laying, and had assumed 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 fighting, must have lain
dormant 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

51 Yarrell, ‘ Phil. Transact.,’ 1827, p. Geoffroy Saint Hilaire, in his ‘ Essais
268; Dr. Hamilton, in ‘ Prog. Zoolog. de Zoolog. Gén.’ (suites 2 Buffon, 1842,
Soc.,’ 1862, p. 23. pp. 496-513), has collected such cases in

52 “ Archiv. Skand. Beitrige zur ten different kinds of birds. It appears
Naturgesch,’ viii. s, 397-413, that Aristotle was well aware of the

°3 In his ‘ Essays on Nat. Hist.,’1838, change in mental disposition in old
Mr. Hewitt gives analogous cases with hens. The case of the female deer

hen-pheasants in ‘Journal of Horti- acquiring horns is given at p. 518.
culture,’ July 12, 1864, p. 87. Isidore
E 2

52 INHERITANCE,

Cnap, XIII,

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 confinement 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 phea-
sant 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 office of a sitter.”*4 That admirable observer
Réaumur® 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 during his whole life
this newly acquired maternal instinct. The many well-ascer-
tained cases of various male mammals giving milk, show that
their rudimentary mammary glands retain this capacity in a
latent condition.

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 circumstances. 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 trans-
mit his superiority in courage and vigour through his female to
his male offspring; and with man it is known™ 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 commencement 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 tlie same sex are present, though
latent, in the intermediate parent of the opposite sex.

The subject of latent characters is so important, as we shall
see in a future chapter, that I will give another illustration.

54 “Cottage Gardener,’ 1860, p. 379.
55 ¢ Art de faire Eclorre,’ &c., 1749, tom. ii. p. 8.
56 Sir H. Holland, ‘ Medical Notes and Reflections,’ 3rd edit., 1855, p. 31.

Cap. XIII. REVERSION. 53

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 reversed manner to what is usual, occasionally occur, and in
Platessa flesus the right or left side is indifferently developed,
the one as often as the other. With gasteropods or shell-fish,
the right and left sides are extremely unequal; the far greater
number of species are dextral, with rare and occasional reversals
of development, and some few are normally sinistral; but cer-
tain species of Bulimus, and many Achatinell, are as often
sinistral as dextral, I will give an analogous case in the great
Articulate kingdom: the two sides of Verruca® are so won-
derfully unlike, that without careful dissection it. is extremely
difficult to recognise the corresponding parts on the opposite
sides of the body ; yet it is apparently a mere matter of chance
whether it be the right or the left side that undergoes so singu-
lar an amount of change. One plant is known to mein which
the flower, according as it stands on the one or other side of the
spike, is unequally developed. : In all the foregoing cases the
two sides of the animal are perfectly symmetrical at an early
period of growth. Now, whenever a species is as liable to be
unequally developed on the one as on the other side, we may
infer that the capacity for such development is present, though
latent, in the undeveloped side. And asa reversal of develop-
ment 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

ie Prof. Thomson on Steenstrup’s 9 Darwin, ‘ Balanide,’ Ray Soc., 1854,
Views on the Obliquity of Flounders > p. 499: see also the appended remarks
‘Annals and Mag. of Nat. Hist.” May, on the apparently capricious develop-

1865, p. 361. ment of the thoracic limbs on the right

°8 Dr. E. von Martens, in ‘ Annals and left sides in the higher crustaceans.
and Mag. of Nat. Hist.,’ March, 1866, °° Mormodes ignea: Darwin, ‘ Ferti-
P. 209, lization of Orchids,’ 1862, p. 251,

54 INHERITANCE. Cuap, XIII

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 cage 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, as they grow old, small horns. Purely bred black and
white bantams, and some other fowls, occasionally assume, with
advancing years, the red feathers of the parent-species. I wil]
here add a somewhat different case, as it connects in a striking
manner latent characters of two classes. Mr. Hewitt ® possessed
an excellent Sebright gold-laced hen bantam, which, as she
became old, grew diseased in her ovaria, and assumed male
characters. In this breed the males resemble the females in all
respects except in their combs, wattles, spurs, and instincts:
hence it might have been expected that the diseased hen would
have assumed only those masculine characters which are proper
to the breed, but she acquired, 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
Sebright bantam is known” 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 common bantam ; and we thus see that not only certain
masculine characters proper to the Sebright bantam, but other
masculine characters derived from the first progenitors of the
breed, removed by a period of above sixty years, were lying
latent in this hen-bird, ready to be evolved as soon as her ovaria
became diseased. 7

From these several facts it must be admitted that certain
characters, capacities, and instincts may lie latent in an indi-
vidual, and even in a succession of individuals, without our being
able to detect the least signs of their presence. We have

61 «Journal of Horticulture, July, Tegetmeier.
1864, p. 38. I have had the oppor- 62 «The Poultry Book,’ by Mr. Teget-
tunity of examining these remarkable meier, 1866, p, 241.
feathers through the kindness of Mr.

, | pmars a <<<] te, wat or. ~> -_~ es a- ah. en «

Cuap. XIII. REVERSION, 55

already seen that the transmission 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
after its third moult, or when purely-bred bantams partially
assume the red plumage of their prototype, we cannot doubt that
these qualities were from the first present, though latent, in the
individual animal, like the characters of a moth in the cater-
pillar. 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 characters from their grand-
parents or more distant progenitors. We should then have had
a case of reversion, that is, of the reappearance in the child
of an ancestral character, actually present, though during youth
completely latent, in the parent; and this we may safely con-
clude is what occurs with reversions of all kinds to progenitors,
however remote.

This view of the latency in each generation of all the cha-
racters which appear through reversion, is also supported 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, we may feel assured, would occasionally produce by
reversion tabbies; and on young black kittens, with a pedi-
gree™ known to have been long pure, faint traces of stripes
may almost always be seen which afterwards disappear. Horn-
less Suffolk cattle occasionally produce by reversion horned
animals; and Youatt “asserts that even in hornless individuals

63 Carl Vogt, ‘ Lectures on Man,’ Eng. translat., 1864, p. 411.
6 On Cattle, p. 174.

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 inhe-
rited 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 genera-
tions, retaining the capacity and tendency 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 hundreds of generations, suddenly reappears, no
doubt some such combination must occur; but reversions may
be constantly 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 difference between the
united forms rendering the resemblance of the offspring to
their grandparents or more remote progenitors of easy detec-
tion. Reversion is likewise 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.

Cuap. XIII. REVERSION, 57

Monstrosities —A large 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 persistence of an em-
bryonic condition. If every horse or ass had striped legs whilst
young, the stripes which occasionally appear on these animals
when adult would have to be considered as due to the ano-
malous 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 connection.

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 animals or plants, occasionally appear, and
these may probably with truth be attributed to reversion. For
instance: supernumerary mamme, 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 chest; and in one
instance a woman (the daughter of another with supernumerary
mammeée) had one mamma, which yielded milk, developed in
the inguinal region. This latter case, when we remember the
position of the mamme 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 mammz in woman
are due to-reversion. The facts given in the last chapter on
the tendency in supernumerary digits to regrowth after amputa-
tion, 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 multipli-
cation of organs, and likewise to their occasional transposition.
The occasional development in man of the coccygeal vertebree
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 development, and as a case of reversion. The
greater frequency of a monstrous kind of proboscis in the pig
than in any other mammal, considering the position of the pig

58 INHERITANCE.

Crap. XIII,

in the mammalian series, has likewise been attributed, perhaps
truly, to reversion.

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, who has ably discussed this
subject, remarks that when, for instance, all the Sepals of a Tropxolum
become green and of the same shape, instead of being coloured with one
alone 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 deve-
lopment; for in these flowers all the organs during their earliest condition
are symmetrical, 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 simple tuft of ereen
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, ag
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 individual plant of the Linaria,’’ they probably stand
in some close relation to each other. On the doctrine that peloria is
simply the result 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 development or to reversion, we may infer from an observa-
tion made by Ch. Morren,® namely, that families which have irregular
flowers often “return by these monstrous growths to their regular form;
whilst we never see a regular flower realise the structure of an irregular
one.”

Some flowers have almost certainly become more or less completely
peloric through reversion. Corydalis tuberosa properly has one of its two
nectaries colourless, destitute of nectar, only half the size of the other, and

65 Tsid. Geoffroy St. Hilaire, ‘Des de Tératologie,’ 1841, pp. 184, 352.
Anomalies, tom. iii. p. 353. With 67 Verlot, ‘Des Variétés, 1865, p.
respect to the mamme in women, see 89; Naudin, ‘Nouvelles Archives du
tom. i. p. 710. Muséum,’ tom. i. p. 137.

66 ‘Natural Hist. Review,’ April, 68 In his discussion on some curious
1863, p. 258. Seealso his Lecture, Royal _ peloric calceolarias, quoted in ‘ Journal
Institution, March 16, 1860. Onsame of Horticulture, Feb. 24, 1863, P.
subject, see Moquin-Tandon, ‘Eléments 152.

Cuap. XIII. REVERSION. 59

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
sucks the perfect nectary, the stigma and stamens are exposed and rubbed
against the insect’s body. In several closely allied genera, as in Dielytra,
&c., there are two perfect nectaries, the pistil is straight, and the hood
slips off on either side, according as the bee sucks either nectary. Now,
T have examined several flowers of Corydalis tuberosa, in which both nec-
taries were equally developed and contained nectar; in this we see only
the redevelopment of a partially aborted organ; but with this redevelop-
ment the pistil becomes straight, and the hood slips off in either direction ;
so that these flowers have acquired 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 shortened filaments being left
as rudiments, and in this respect they resemble 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, Geranium, and Erodium.

In the peloric form of Antirrhinum majus, appropriately called the
“ Wonder,” the tubular and elongated flowers differ wonderfully 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 un-
equal stamens. One of the two additional stamens is manifestly formed
by the development of a microscopically minute papilla, which may be
found at the base of the upper lip of the flower in all common snap-
dragons, at least in nineteen plants examined by me. That this papilla
is a rudiment of a stamen was well shown by its various degrees of deve-
lopment in crossed plants between the common and peloric Antirrhinum.
Again, a peloric Galeobdolon lutewm, growing in my garden, had five equal
petals, all striped like the ordinary lower lip, and included five equal
instead 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. Now, as the mem-
bers 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 either case as due to reversion, any more than the
additional petals in double flowers in these same two families. But the
case is different with the fifth stamen in the peloric Antirrhinum, which

® For other cases of six divisions in pelorie flowers of the Labiate and
Scrophulariacese, see Moquin-Tandon, ‘ Tératologie,’ p. 192.

-is produced by the redevelopment of a rudiment alwa

60 INHERITANCE. Cuap. XIII,

yS present, and
which probably 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 full 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 progenitor 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 development, nor as due to the rede-
velopment of rudiments, for no rudiments are present, and as these addi-
tional 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 rudi-
mentary or to be wholly suppressed,—the redevelopment of

parts at present in a more or less rudimentary condition,—the

reappearance of organs of which not a vestige can now be de-
tected,—and to these may be added, in the case of animals, the
presence during youth, and subsequent disappearance, of cer-
tain characters which occasionally are retained throughout life.
Some naturalists look at all such abnormal structures as a return
to the ideal state of the group to which the affected being
belongs ; but it is difficult to conceive what is meant to be con-
veyed by this expression. Other naturalists maintain, with
greater probability and distinctness of view, that the common
bond of connection between the several foregoing cases is an
actual, though partial, 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 hidden 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 occasionally
become peloric; but many more cases have been observed
in the Labiate and Scrophulariaces: than in any other order ;
and in one genus of the Scrophulariacez, namely Linaria, no less

an

Cuap, XIII. REVERSION. 61

than thirteen species have been described in a pelorice condition.”
On this view of the nature of peloric flowers, and bearing in
mind what has been said with respect to certain monstrosities
in the animal kingdom, we must conclude that the progenitors
of most plants and animals, though widely. different in struc-
ture, have left an impression capable of redevelopment on the
germs of their descendants.

The fertilised germ of one of the higher animals, subjected 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, without 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.

© Moquin-Tandon, ‘ Tératologie, p: 186.

a

62 INHERITANCE. Cuar, XIV

Une tae Re RLY;

INHERITANCE continued — FIXEDNESS OF CHARACTER — PREPO-
TENCY — SEXUAL LIMITATION — CORRESPONDENCE OF AGR.

FIXEDNESS OF CHARACTER APPARENTLY NOT DUE TO ANTIQUITY OF INHERITANCE —
PREPOTENCY OF TRANSMISSION IN INDIVIDUALS OF THE SAME FAMILY, IN CROSSED
BREEDS AND SPECIES; OFTEN STRONGER IN ONE SEX THAN THE OTHER; SOME-
TIMES 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 py
ONE SEX ALONE, SOMETIMES LOST BY ONE SEX ALONE — INHERITANCE AT COoR-
RESPONDING PERIODS OF LIFE — THE IMPORTANCE OF THE PRINCIPLE WITH RESPECT
TO EMBRYOLOGY; AS EXHIBITED IN DOMESTICATED ANIMALS; AS EXHIBITED IN
THE APPEARANCE AND DISAPPEARANCE OF INHERITED DISEASES; SOMETIMES

SUPERVENING EARLIER IN THE CHILD THAN IN THE PARENT — SUMMARY OF THE
THREE PRECEDING CHAPTERS.

In the two last chapters the nature and force of Inheritance, the
circumstances which interfere with its power, and the tendency
to Reversion, with its many remarkable contingencies, were dis-
cussed. 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 wish 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 proposition 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, m
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,

|

Cuar. XIV. FIXEDNESS OF CHARACTER, ' 63

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, &c.,
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 transmitted. Some varieties, such as
white and yellow hyacinths 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 colouring of the
eyes was transmitted far more faithfully than any ordinary colour.
Ancon and Mauchamp sheep and niata cattle, which are all com-
paratively modern breeds, exhibit remarkably strong powers of
inheritance. Many similar cases could be adduced.

As all domesticated animals and cultivated plants have 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 transmitted perfectly true. In this
case, however, it may be said that changed conditions of life
induce certain modifications, and not that the power of inherit-
ance 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 fail 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
have been modified

species of the same genus
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 organi-
sation have remained unchanged ; and it might be argued that

64 INHERITANCE. Cuap, XIV

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 structures which during
an immense lapse of time have remained unaltered; and this
variation is probably the result of certain relations between the
conditions ot life and the organisation, quite independently of
the greater or less antiquity of each particular character,
Fixedness of character, or the strength of inheritance, hag
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 imme-
diately see, is a very different consideration from the strength
or weakness of inheritance. It has often been observed! that
breeds of animals inhabiting wild and mountainous countries
cannot 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 constitution 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. Notwithstanding these
considerations, it would perhaps be rash to deny that characters
become more strongly fixed the longer they are transmitted;
but I believe that the proposition 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 counteracting influences and been truly transmitted, will, as
a general rule, continue to withstand them, and consequently

be faithfully inherited.

1 See Youatt on Cattle, pp. 92, 69, 78, 88, 163: and Youatt on Sheep, p. 929.
Also Dr. Lucas, ‘ L’Héréd. Nat.,’ tom. ii. p. 310.

)

Cuap, XIV. PREPOTENCY OF TRANSMISSION, 65

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 offspring in the first generation are inter-
mediate 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,? but 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 cha-
racters, which render the comparison of mongrels with their
parent-breeds difficult,

It would appear that in certain families some one ancestor,
and after him others in the same family, must have had oreat
power in transmitting their likeness through the male line ‘
for we cannot otherwise understand how the same features
should so often be transmitted 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.’ The famous bull Favourite
is believed‘ to have had a prepotent influence on the short-
horn race. It has also been observed® with English race-horses
that certain mares have generally transmitted their own cha-

racter, 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, notwithstanding
that the breed ig comparatively modern, are generally acknowledged 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

By crear att = le Dial SOD

ae Nat.’ tom. ii, pp. F12- 4 ‘ Gardener's Chronicle, 1860, p. 270.

3 Sir H, Holland, Chapters on Mental
Physiology,’ 1852, p. 234,
VOL. II.

° Mr. N. H. Smith, Observations on
Breeding, quoted in ‘ Encyclop. of Rural
Sports,’ p. 278,

F

=< i

66 INHERITANCE, Car, XIV,
for exportation. Godine has given a curious case of a ram of a eoat-lik
* 5 ike

breed of sheep from the Cape of Good Hope, which 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 Buzareingues’ found that of two races of French sheep the exten
of one, when 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 shee
and with cattle, the prepotency running in these cases through the male
side; but I was assured on good authority in South America, that when
niata cattle are crossed with common cattle, though the niata breed is pre-
potent whether males or females are used, yet that the prepotency igs
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, seventeen were destitute of tails; but when the
female Manx was crossed by common male cats all the kittens had t
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 1
preponderated over fantails. This weakness of transmission in the fantail,
though the breed is an ancient one, is said® 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 peculiar 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 Corbié™ assert that this
is the invariable result of crossing trumpeters with any other breed: .
Neumeister,” however, states that in Germany mongrels have been obtained,
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” that the crossed offspring of a trumpeter were crossed

ails,

6 Quoted by Bronn, ‘ Geschichte der 8 Mr. Orton, ‘Physiology of Breed-
Natur, b. ii. s. 170. See Sturm, ing, 1855, p. 9.
‘Ueber Racen,’ 1825, s. 104-107. For 9 Boitard and Corbié, ‘Les Pigeons,
the niata cattle, see my ‘Journal of 1824, p. 224.

————————

Researches,’ 1845, p. 146. 10 «Les Pigeons,’ pp. 168, 198.
7 Lucas, ‘]’Hérédité Nat.,’ tom. ii. p. 1 *¢Das Ganze,’ &e., 1837, s. 39. |
iL. 12 «'The Pigeon Book,’ p. 46. )

Cuap. XIV. PREPOTENCY OF TRANSMISSION. 67

with trumpeters for three generations, by which time the mongrels had
-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 15-16ths trumpeter’s blood, still did not trumpet. This case
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 crossed 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 mongrels 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 no 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 ban-
tam-hen, had silky feathers. So that it is certain that this breed very
seldom 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 general qualities; but the silk sub-
variety when crossed with any other small-sized race invariably trans-
mits its silky feathers! 4

The law of prepotency comes into action when species are crossed, as
with races and individuals. Giirtner has unequivocally shown® that this
is the case with plants. To give one instance: when Nicotiana panicu-
lata and vinceeflora are crossed, the character of N. paniculata is almost
completely lost in the hybrid; but if WN. quadrivalvis be crossed with
N, vinceflora, this latter Species, which was before go prepotent, now
in its turn almost disappears under the power of N. quadrivalvis. Tt is
remarkable that the prepotency of one species over another in transmission
is quite independent, as shown by Girtner, 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
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.’® The

oe inlA ce LL

*’ ‘Physiology of Breeding,’ p, 22; Muséum, tom. i. p. 149) gives a striking
Mr. Hewitt, in ‘ The Poultry Book,’ by — instance of prepotency in Datura stramo-
Tegetmeier, 1866, p. 224, nium when crossed with two other

Boitard and Corbié, « Les Pigeons, species,

1824, p, 226, 6 Flourens, ‘ Longévité Humaine,’

» ‘Bastarderzeugung,” s, 256, 290, p. 144, on crossed jackals. With
&ce. Naudin (‘ Nouvelles Archives du respect to the difference between the

re

68 INHERITANCE,

CHap, XIV,

male pheasant, judging from Mr. Hewitt’s descriptions.” 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 trans-
mission, for hybrids raised from five differently coloured hens differed
greatly in plumage. I formerly examined some curious hybrids in the
Zoological Gardens, between the Penguin variety of the common duck
and the Egyptian goose (Anser Agyptiacus); and although I will not
assert 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 prepotent over the
other in impressing its character on its crossed offspring, 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 hag
fully discussed this point, and has shown” that none of the rules (and
I could add others to those quoted by him) apply to all animals. Similar
rules have been enounced for plants, and have been proved by Girtner”
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 imstance, it seems that in reciprocally
crossing various breeds of fowls the male generally gives colour;” but
conspicuous exceptions have passed under my owneyes. 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 trans-

mule and the hinny, I am aware that
this has generally been attributed to
the sire and dam transmitting their
characters differently; but Colin, who
has given in his ‘Traité Phys. Comp.,
tom. ii. pp. 537-539, the fullest descrip-
tion which I have met with of these
reciprocal hybrids, is strongly of
opinion that the ass preponderates in
both crosses, but in an unequal degree.
This is likewise the conclusion of
Flourens, and of Bechstein in his
‘Naturgeschichte Deutschlands,’ b. i.
8. 294. The tail of the hinny is much
more like that of the horse than is the
tail of the mule, and this is generally
accounted for by the males of both
species transmitting with greater power
this part of their structure; but a com-
pound hybrid which I saw in the
Zoological Gardens, from a mare by
a hybrid ass-zebra, closely resembled
its mother in its tail.

WV Mr. Hewitt, who has had such
great experience in raising these hy-
brids, says (‘ Poultry Book,’ by Mr.
Tegetmeier, 1866, pp. 165-167) that in
all, the head was destitute of wattles,
comb, and ear-lappets; and all closely
resembled the pheasant in the shape of
the tail and general contour of the body.
These hybrids were raised from hens
of several breeds by a cock-pheasant;
but another hybrid, described by Mr.
Hewitt, was raised from a hen-peasant ;
by a silver-laced Bantam cock, and
this possessed a rudimental comb and
wattles. Fy

18 «T/Héréd. Nat.,’ tom. ii. book it.
ch. i.

19 « Bastarderzeugung, 8. 264-266.
Naudin (‘Nouvelles Archives du
Muséum,’ tom. i. p. 148) has arrived
at a similar conclusion.

20 «Cottage Gardener, 1856, pp. 101,
137.

—

Cuap. XIV, PREPOTENCY OF TRANSMISSION. 69

mitted 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 repeated crosses, depends in chief part on pre-
potency in transmission.

Tn conclusion, some of the cases above given,—for instance,
that of the trumpeter pigeon,—prove that there is a wide dif-
ference between mere inheritance and prepotency. 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 different 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 mongrelized
and already variable form.?! From several of the above-
given cases we may conclude that mere antiquity of character
does not by any means necessarily make it prepotent. In
some cases prepotency apparently depends on the same cha-
racter 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 poten-
tially present in both should be prepotent. Thus, we 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 off-
spring are almost sure to be striped. Sheep have a similar
latent tendency to become dark-coloured, and we have seen with
what prepotent force a ram with a few black spots, when crossed
with white sheep of various breeds, coloured its offspring. All
pigeons have a latent tendency to become slaty-blue, with certain
characteristic marks, and it is known that, when a bird thus
coloured is crossed with one of any other colour, it is most diffi-
cult afterwards to eradicate the blue tint. A nearly parallel
case is offered by those black bantams which, as they grow

21 See some remarks on this head with respect to sheep by Mr, Wilson, in
‘Gardner’s Chronicle,’ 1863, p. 15.

70 INHERITANCE,
old, develop a latent tendency to acquire red feathers, But
there are exceptions to the rule: hornless breeds of cattle
possess a latent capacity to reproduce horns, yet when 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 ten-
dency to become uniformly coloured, but when once crossed by
a uniformly coloured variety, they ever afterwards fail to pro-
duce striped seedlings.” Another case is in some respects more
curious: plants bearing peloric or regular flowers have so strong
a latent tendency to reproduce their normally irregular flowers,
that this often occurs by buds when a plant is transplanted into
poorer or richer soil.’ Now I crossed the peloric snapdragon
(Antirrhinum majus), described in the last chapter, with pollen
of the common form ; and the latter, reciprocally, with peloric
pollen. I thus raised two great beds of seedlings, and not one
was peloric. Naudin™ obtained the same result from crossing a
peloric 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 present, was more fully or even
completely developed. It must not be supposed that this entire
obliteration of the peloric structure in the crossed plants can
be accounted for by any incapacity of transmission; for I raised
a large bed of plants from the peloric Antirrhinum, artificially
fertilised by its own pollen, and sixteen plants, which aloue
survived the winter, were all as perfectly peloric as the parent-
plant. Here we have a good instance of the wide difference
between the inheritance of a character and the power of trans-
mitting it to crossed offspring. he crossed plants, which per-
fectly resembled the common snapdragon, 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 condition between the peloric and normal state,

22 Verlot, ‘Des Variétés,’. 1865, p. 66,
23 Moquin-T'andon, ‘ Tératologie,’ p. 191.
*4 « Nouvelles Archives du Muséum,’ tom. i. p. 187,

Cuap, XIV. SEXUAL LIMITATION. 71

and thirty-seven were perfectly peloric, 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 when the two forms
are crossed, Jor in all the Scrophulariacez, and especially in the
genera Antirrhinum and Linaria, there is, as was shown in the last
chapter, a strong latent tendency to become peloric; and there
is also, as we have just seen, a still stronger tendency in all
peloric plants to reacquire their normal 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 Snap-
dragon, prevailed in the first generation; whilst the tendency
to pelorism, appearing to gain strength by the intermission of
a generation, 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 considered in the
chapter on pangenesis.

On the whole, the subject of prepotency is extremely intri-
cate,—from its varying so much in strength, even in regard to
the same character, in different animals,—from its running either
equally in both sexes, or, as frequently i is the case with ais
but not with plants, much stronger in the one sex than the
other,—from the existence of secondary sexual characters,—
from the transmission of certain characters being limited, as we
shall immediately see, by sex,—from certain eiadetiera not
blending together,—and, perhaps, occasionally from the effects
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 prepotency.

Inheritance as limited by Sex,

New characters often appear in one sex, and are afterwards
transmitted to the same sex, either exclusively or in a much
greater degree than to the other. This subject is important,
because with animals of many kinds in a state of nature, both
high and low in the scale, secondary sexual characters, not in

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72 INHERITANCE.

Crap, XIV,

any way directly connected with the organs of reproduction, are
often conspicuously 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 sex
shows how such characters might have been first acquired and
subsequently modified.

Dr. P. Lucas, who has collected many facts on this Subject, shows
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 various diseases, especially with colour-blindness, and a hemorrhagic
diathesis, that is, an extreme liability to profuse and uncontrollable
bleeding from trifling wounds. On the other hand, mothers have trans-
mitted, during several generations, to their daughters alone, supernumerary
and deficient digits, colour-blindness, and other peculiarities. So that we
see that the very same peculiarity may become 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 peculi-
arities also may be promiscuously transmitted to either sex. Dr. Lucas gives
other cases, showing that the male oceasionally 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 weighing 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,” 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 women. In the case given by Dr. Earle,
members of eight related families were affected during five generations:
these families consisted of sixty-one individuals, namely, of thirty-two males,
of whom nine-sixteenths were incapable of distinguishing colour, and of

twenty-nine females, of whom only one-fifteenth were thus affected. Al-

5 « T’Héréd. Nat.,’ tom. ii. pp. 137- tary Diseases, ‘ Brit. and For. Med.-
165, See, also, Mr. Sedgwick’s four Chirurg. Review? April, 1861, p. 477;
memoirs, immediately to be referred to. July, p. 198; April, 1863, p. 449 ; and

** On Sexual Limitation in Heredi- July, p. 159.

:
'

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Cap, XIV. SEXUAL LIMITATION. 73

though colour-blindness thus generally clings to the male sex, nevertheless,
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 hemorrhagic diathesis, often accompanied by rheumatism, has been known
to affect the males alone during 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 hands and feet, transmitted the pecu-
liarity to his two sons and one-daughter;. but in the third generation,
out of nineteen grandchildren, twelve sons had the family detect, 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 hemorrhagic 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 pecu-
liarity,—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. Sedgwick,
and others, there can be no doubt that peculiarities first appearing in either
sex, though not in any way necessarily or invariably 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 characters
not proper to the parent-species are often confined to, and inherited 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 accounted 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
have a larger hump than the cow. In the Scotch deer-hound the two sexes
differ in size more than in any other variety of the dog,” 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 tendency to baldness in man before the advent
of old age is certainly inherited; and in the European, or at least in the

27
2

27 W. Scrope, ‘ Art of Deer Stalking,’ p. 354.

74. INHERITANCE

CHAP, XIV,

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 these differences are far from being
tinguish the two sexes in the parent-s

consequently have originated under domestication. In certain sub-varieties
of the Game race we have the unusual 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 two
Sexes rarely differ throughout the whole great family, and the males and
females of the parent-form, the Ci livia, are undistinguishable; yet we have
seen that with Pouters the male has the characteristic quality of pouting
more strongly developed than the female; and in certain sub-varieties ‘8
the males alone are spotted or striated with black. When male and female
English carrier-pigeons are exhibited in Separate pens, the difference in
the development of the wattle over the beak and round the eyes is con-
Spicuous. So that here we have instances of the appearance of secondary

sexual characters in the domesticated races of a species in which such dif-
ferences are naturally quite absent.

and females often differ greatly ;
the same with those which dis-
pecies, the Gallus bankiva; and

On the other hand, secondary sexual characters which pro-
perly 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 which 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
transferred 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 occasionally 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

*S Boitard and Corbié, ‘Les Pigeons, p, 173; Dr, F, Chapuis, ‘Le Pigeon
Voyageur Belge,’ 1865, p. 87.

ee

Cuap. XIV. AT CORRESPONDING PERIODS. 75

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 accordance 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 remark-
able of all the facts in biology, namely, the difference between
the embryo and the adult animal. ‘he explanation is, that
variations do not necessarily or generally occur at a very early
period of embryonic growth, and that such variations are inhe-
rited at a corresponding age. As a consequence of this the
embryo, even when the parent-form undergoes a great amount
of modification, is left only slightly modified; and the embryos
of 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 conditions 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 animals
and plants, which, when compared with each other and with
their parent-forms, present conspicuous differences, 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-

76 INHERITANCE Cap, XIV

grown plants differ but little. Cabbages on the other hand differ
greatly in foliage and manner of growth, but hardly at all in
their seeds; and generally it will be found that the differences
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 distinguishable, yet differ much when full.
grown. In the several breeds of poultry, descended from a single
species, differences in the eggs and chickens, in the plumage 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 inhe-
ritable, and with man longevity is often transmitted. So again
with our improved breeds of cattle and sheep, early maturity,
including the early development of the teeth, and with certain
breeds of fowl the early appearance of secondary sexual cha-
racters, all come under the same head of inheritance at
corresponding periods. |

Numerous analogous facts could be given. The silk-moth,
perhaps, offers the best instance; for in the breeds which
transmit their characters truly, the egos differ in size, colour,
and shape ;—the caterpillars differ, in moulting 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 distin-
guishable differences in the mature moth.

But it may be said that, if in the above cases a new pecu-
liarity 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-crown ox can resemble only a horn.
The following cases show inheritance 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 ap-
peared,

In the Lambert family the porcupine-like exerescences appeared in
the father and sons at the same age, namely, about nine weeks after

Cnar. XIV. AT CORRESPONDING PERIODS. 77

birth.” In the extraordinary hairy family described by Mr. Crawfurd,%°
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 earlier, namely, at one year; and in both generations
the milk teeth appeared late in life, the permanent 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
fall beauty and peculiar character of the plumage does not appear 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. 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.”® A curious
and somewhat analogous account has been given ® of a family of wild pied
rooks which were first observed in 1798, near Chalfont, and which every
year from that date up to the period of the published notice, viz. 1887,
“have several of their brood particoloured, 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
corresponding periods of life in the pigeon, canary-bird, and rook, are
remarkable, 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 connected with any
change in structure; but in other respects of more value, because the
periods have been more carefully observed. Certain diseases are com-
municated 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. Vitus’s dance
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

29 Prichard, ‘ Phys. Hist. of Mankind,’ 31 * Das Ganze der Taubenzucht,’ 1837,
1851, vol. i. p. 349. 1g. 21; tab. 1, fig. 4; 8. 24, tab iv.,
59 «Embassy to the Court of Ava? fig. 2.
vol. i. p. 320. The third generation is ® Kidd’s ‘Treatise on the Canary,’
described by Capt. Yule in his ‘ Narra- p. 18.
tive of the Mission to the Court of Aya, 83 Charlesworth, ‘Mag. of Nat. Hist.,’
1855, p. 94. vol. i. 1837, p. 167.

a Ok i) ae ee ee ee ae

78 INHERITANCE Cuap, XIV,

dance, showing that an unusually early or late tendency to the disease
is inheritable.* In most cases the appearance of any inherited disease ig
largely determined by certain critical periods in each person’s life, as well]
as by unfavourable conditions. There are many other diseases, which
are not attached to any particuliar period, but which 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® cautions the physician to look closely to the child
at the period when any grave inheritable disease attacked the parent,
Dr. Prosper Lucas,” after collecting 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 instances, simply
as illustrations, not as proof; for proof, recourse must be had to the autho-
rities above quoted. Some of the following 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 blindness 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.” 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.® So
with deafness, two brothers, their father and paternal grandfather, all
became deaf at the age of forty.®

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. Other cerebral
affections sometimes follow the same rule,—for instance, epilepsy and
apoplexy. A woman died of the latter disease when sixty-three years old;
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 in the precise nature of an inherited disease, though
still affecting the same organ.

** Dr. Prosper Lucas, ‘Héréd, Nat.,’ I have not been able to consult), and all
tom. ii. p. 713. differ in the details! but as they agree

* «L’Héréd. dans les Maladies, 1840, in the main facts, I have ventured to
p. 135. For Hunter, see Harlan’s quote this case.

‘Med. Researches,’ p. 530. 38 Prosper Lucas, ‘ Héréd. Nat.’ tom.
%° < T’Héréd, Nat.,’ tom. ii. p. 850. i. p. 400.
7 Sedgwick, ‘Brit. and For. Med.- 39 Sedgwick, idem, July, 1861, p. 202.

Chirurg. Review, April, 1861, p. 485. 40 Piorry, p. 109; Prosper Lucas,
I have seen three accounts, all taken tom. ii. p. 759.
from the same original authority (which 41 Prosper Lucas, tom. ii. p. 748.

A

Cuap, XIV, AT CORRESPONDING PERIODS. cy

Asthma has attacked several members of the same family when forty
years old, and other families during infancy. The most different 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.*2

I will give only two other cases, which are interesting as illustrating 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, paternal
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.

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, especially in the
case of rare affections in which the coincidence 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 direc-
tion bemg very much rarer. Dr. Lucas“ alludes to several
cases of inherited diseases coming on at an earlier period. I
have already given one striking instance with blindness during
three generations ; and Mr. Bowman remarks that this frequently
occurs with cataract. With cancer there seems to be a peculiar
liability to earlier inheritance : Mr. Paget, who has particularly

® Prosper Lucas, tom. ii. pp. 678, *8 These cases are given by Mr.
.700, 702; Sedgwick, idem, April, 1863, Sedgwick, on the authority of Dr. H.
p. 449, and July, 1863, p. 162; Dr. J. Stewart, in ‘Med.-Chirurg. Review,’
Steinan, ‘ Essay on Hereditary Disease,’ April, 1868, pp. 449, 477.
1843, pp. 27, 34, 44 « Héréd, Nat.,’ tom. ii. p. 852.

a ae a eo eT, ee cee eel ietaeOe fes Sere

80 INHERITANCE, Cuap. XIV:

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 generation suffers from the disease at an earlier period than

the ene generation. He adds, “In the instances in which
the opposite relation holds, and the members of later genera-
tions have cancer at a later age than their predecessors, I think
it will be found that the non-cancerous 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 complexity 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 structure. The final result
of a long series of such advances would be the gradual oblite-
ration of characters proper to the embryo and larva, which
would thus come to resemble 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 character.

Fimally, from the numerous races of cultivated plants and
domestic animals, in which the seed or eggs, the young or
old, differ from each other and from their parent-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 inherit-
ance at corresponding periods of life.

Summary of the three preceding Ohapters.—Sirong as is the
force of inheritance, it allows the incessant appearance 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 s0 perfect

Crap. XIV. SUMMARY. 81

and complex as the eye; or of so grave a nature as to deserve
to be called a monstrosity, 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 characterised.
Inequalities in the two sides of the body, though opposed to
the law of symmetry, may be transmitted. There is a con-
siderable 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 transmitted, but generally,
as it would appear, with little force.

Hence we are led to look at inheritance ag the rule, and
non-inheritance as the anomaly. But this power often appears
to us in our ignorance to act capriciously, transmitting a cha-
racter with inexplicable strength or feebleness. The very
same peculiarity, as the weeping habit of trees, silky-feathers,
&c., may be inherited either firmly or not at all by different
members of the same group, and even by different 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 propagated 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 stil]
form parts of the same individual, for some varieties retain or
inherit through successive bud-generations their character far
more truly than others.

Some characters not proper to the parent-species have cer-
tainly been inherited from an extremely remote epoch, and may
therefore be considered as firmly fixed. Butitis doubtful whether

length of inheritance in itself gives fixedness of character ; though
VOL. It, ee

82, INHERITANCE. Cuap. XIV,

the chances are obviously in favour of any character which has
long been transmitted 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 character
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 absolutely 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 conditions causing new and slight modifications incessantly
to appear. In this latter case it is not that imheritance wholly
fails, but that new characters are continually superadded. In
some few cases, in which both parents are similarly charac-
terised, inheritance seems to gain so much force by the com-
bined action of the two parents, that it counteracts its own power,
and a new modification is the result.

In many cases the failure 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 variation, 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 are latent, like the secondary sexual
characters of one sex in the other. When, after a long suc-
cession 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 detected only in an intimately com-
mingled 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,

Cuap, XIV. SUMMARY. 83

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 generations 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, certainly gives a strong
tendency to the reappearance of long-lost characters, both. cor-
poreal and mental, independently of those derived from the
cross. A return of any species to its natural conditions of life,
as with feral animals 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 inheritance, and yet when crossed,
as we have seen with trumpeter-pigeons, yield to the prepo-
tency 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 some-
times depends on the same character being present and visible
in one parent, and latent or potentially present in 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, Tp this
fident 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 grandson; and the

G 2

case we may feel con-

84 INHERITANCE, CHAP. XIV,

mother conversely to her granddaughter. We thus learn, and
the fact is an important one, that transmission and development
are distinct powers. Occasionally these two powers seems to be
antagonistic, or incapable of combination in the same individual ;
for several cases have been recorded in which the son has not
directly inherited a character from his father, or directly trang.
mitted 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 secondary sexual characters may first have
arisen under nature; their preservation and accumulation being
dependent 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 corresponding
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 corre-
sponding periods, we can understand how it is that most animals
display from the germ to maturity such a marvellous succession
of characters. fF

Finally, though much remains obscure’ with respect to In-
heritance, we may look at the following laws as fairly well esta-
blished. Firstly, a tendency in every character, new and old, to
be transmitted by seminal and bud generation, 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 character. In these laws of in-
heritance, as displayed under domestication, we see an ample
provision for the production, through variability and natural
selection, of new specific forms.

Cuar. XY. ON CROSSING. 85

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 TRANS-
MISSION, BY THE CONDITIONS OF LIFE, AND BY NATURAL SELECTION — ALL OR-
GANIC BEINGS OCCASIONALLY INTERCROSS ; APPARENT EXCEPTIONS — ON CERTAIN
CHARACTERS INCAPABLE OF FUSION ; CHIEFLY OR EXCLUSIVELY THOSE WHICH
HAVE SUDDENLY APPEARED IN THE INDIVIDUAL — ON THE MODIFICATION OF OLD
RACES, AND THE FORMATION OF NEW RACES, BY CROSSING — SUME CROSSED RACES
HAVE BRED TRUE FROM THEIR FIRST PRODUCTION — ON THE CROSSING OF DISTINCT
SPECIES IN RELATION TO THE FORMATION OF DOMESTIC RACES.

ty 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 cha-
racters, 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
characters. I shall also show that certain characters are incap-
able of fusion.

The effects 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 dis-
cussed at much length. It is free intercrossing which chiefly
gives uniformity, both under nature 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 variability. The prevention of free crossing, and the
intentional 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

83 ON CROSSING AS A CAUSE Cuap, XY,

same thing as their separation. In savage and semi-civilised
countries, where the inhabitants have not the means of sepa-
rating 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 together.’ The cele-
brated agriculturist Marshall? remarks that “ sheep that are
“ kept within fences, as well as shepherded flocks in open.
“countries, have generally a similarity, if not a uniformity,
“ of character in the individuals of each flock ;” for they breed
freely together, and are prevented from crossing with other
kinds; whereas in the unenclosed parts of England the un-
shepherded 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 gene-
rations, 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 hun-
dred and fifty, is partly due to their remaining, differently from
other domesticated birds, paired for life when once matched.
On the other hand, breeds of cats imported into this country
soon disappear, for their nocturnal and rambling habits render
it hardly possible to prevent free crossing. Rengger® gives an
interesting case with respect to the cat in Paraguay: in all the

distant parts of the kingdom it has assumed, apparently 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 Hurope. In all cases like the foregoing, the effects 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 monerels increasing

more rapidly than the pure parent-breeds.

‘ Communications to the Board of land, 1808, p. 200.
Agriculture, vol. i. p. 367. ? “Siugethiere von Paraguay,’ 1830,
? “Review of Reports, North of Eng- s. 212.

We

ee ae

Cuap. XV. OF UNIFORMITY OF CHARACTER. 87

When distinct breeds are allowed to cross freely, the result
will be a heterogeneous body; for instance, the dogs in Para-
guay are far from uniform, and can no longer be affiliated to
their parent-races.*| The character which a crossed body of
animals will ultimately assume must depend on several con-
tingencies,—namely, on the relative numbers of the individuals
belonging to the two or more races which are allowed to mingle ;
on the prepotency 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 favoured in
all respects, as might have been expected. The following cal-
eulation® 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 the number of blacks, whites, and mulattoes would be
“equal. In 91 years the whites would be 1-10th, the blacks
“ ]-10th, and the mulattoes, or people of intermediate degrees of
“ eolour, 8-10ths of the whole number. In three centuries not
“ 1-100th 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.? 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;* but the imported races no doubt were
favoured. Rats may be considered as semi-domesticated
animals. Some snake-rats (Mus alevandrinus) 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.’ On the other hand,

* Rengger, ‘ Saugethiere,’ &., s.154. ject, and ably discussed it.

> White, ‘Regular Gradation in Man,’ 7 Rey. D. Tyerman, and Bennett,
p. 146. ‘Journal of Voyages, 1821-1829, vol.
° Dr. W. F, Edwards, in his‘ Charac- i. p. 300.
teres Physiolog. des Races Humaines,’ 8 Mr. S. J. Salter, ‘Journal Linn,

p. 24, first called attention to this sub- Soe.,’ vol. vi., 1862, p. 71.

88 ON CROSSING AS A CAUSE Cuap, XV;

in some parts of London, especially near the docks, where fresh
rats are frequently imported, an endless variety of intermediate
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 ;°
and the requisite number has probably been much exagee-
rated. Some writers have maintained that a dozen, or score,
or even more generations, are necessary; but this in itself is
improbable, for in the tenth generation there will be only
1-1024th part of foreign blood in the offspring. Girtner found,”
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 generations. In one
instance, however, Kélreuter™ speaks of the offspring’ of Mira-
bilis vulgaris, crossed during eight successive generations by MV,
longiflora, as resembling this latter species so closely, that the
most scrupulous observer could detect “vix aliquam notabilem
differentiam ;”—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
Kélreuter are of far higher worth than those made without
scrientific 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,” who, in reference
to German sheep, says “that the original coarse sheep have
“5000 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 succes-
sively with Merinos have not by any means acquired wool as fine
as that of the pure breed. In all cases, the rate of absorption will

9 Sturm, ‘ Ueber Racen, &c.,’ 1825, s. 10 ¢ Bastarderzeugung,’ s. 463, 470.
107. Bronn, ‘Geschichte der Natur, 11 “Nova Acta Petrop.,’ 1794, p. 393:
b. ii. s. 170, gives a table of the propor- see also previous volume.

tions of blood after successive crosses, 2 As quoted in the ‘True Principles
Dr. P. Lucas, ‘ 1 Hérédité Nat.,’ tom. ii. of Breeding, by C. H. Macknight and
p. 308. Dr. H. Madden, 1865. p. 11.

SR a

Cuap, XV. OF UNIFORMITY OF CHARACTER. 89

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 degene-
ration in the wool of Merinos, unless prevented by careful
selection; and thus perhaps the foregoing remarkable case may
be explained. The rate of absorption must also depend on the
amount of distinguishable difference between the two forms
which are crossed, and especially, as Gartner insists, on pre-
potency 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 subsequent
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 accustomed to the country where
they live, they will, in all probability, be unequally affected by
the conditions, and this will modify the result. ven with indi-
genous 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 carefully tended, as will
generally be the case with breeds allowed to cross. As a con-
sequence of this, natural selection 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 will require before such a crossed body
of animals would assume within a limited area a uniform cha-
racter no one can say; that they would ultimately become
uniform from free intercrossing, and from the survival of the
fittest, we may feel assured; but the character thus acquired
would rarely or never, as we may infer from the several previous

90 ON ALL ORGANIC BEINGS Cuap, XV,

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 crossing
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 im-
portant part in giving to all the members of the same domestic
race, and of the same natural species, uniformity of character,
though largely modified by natural selection and by the direct
action of the surrounding conditions.

On the possibility of all organie beings occasionally entercrossing.
—But it may be asked, can free crossing occur with herma-
phrodite animals and plants? All the higher animals, and the
few insects which have been domesticated, have separated sexes,
and must inevitably unite for each birth. With respect to the
crossing of hermaphrodites, the subject is too large for the pre-
sent volume, and will be more properly treated in a succeeding
work. In my ‘Origin of Species,’ however, I have given a
short abstract of the reasons which induce me to believe that
all organic beings occasionally cross, though perhaps in some
cases only at long intervals of time.” 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 dichogamous, in which the pollen and stigma of the
same flower are matured at different periods; or those called
by me reciprocally dimorphic, 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, effec-
tually preventing self-fertilisation. There are, however, many
hermaphrodite plants which are not in any way specially con-
structed to favour intercrossing, but which nevertheless com-
mingle almost as freely as animals with separated sexes. ‘This
is the case with cabbages, radishes, and onions, as I know from

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

CHar. XV. OCCASIONALLY INTERCROSSING. 91

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, Gallesio remarks that
the amelioration of the various kinds is checked by their con-
tinual 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 structure of these flowers certainly favours
an occasional cross. The varieties of the tomato and aubergine
(Solanum) and pimenta (Pimenta vulgaris?) are said never
to cross, even when growing alongside each other. But it should
be 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 perpetually
self-fertilised, as in the case of the Bee Ophrys (0. apzfera),
though adapted in its structure to be occasionally crossed. ‘The
Leersia oryzoides produces minute enclosed flowers which cannot
possibly be crossed, and these alone, to the exclusion of the
ordinary flowers, have as yet been known to yield seed."© 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 in-
tercross, and that some great advantage is derived from this act.
It is well known (and I shall hereafter have to give instances)
that some plants, both indigenous and naturalised, 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
different conditions, or that they formerly did so and will do
so again. On analogous grounds, I believe that the few flowers

44 «Teoria della Riproduzione Vegetal, 1816, p12.
15 Verlot, ‘ Des Variétés,’ 1865, p. 72.
16 Duyal-Jouve, ‘Bull, Soc. Bot. de France,’ tom. x., 1863, p. 194.

92 ON CERTAIN CHARACTERS Cuap, XY,

which do not now intercross, either would do so under different
conditions, or that they formerly fertilised each other at intervals
—the means for effecting this being generally still retaineqd—
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 uniformity
to the individuals of the same species, namely, the capacity
of occasionally intercrossing, is present, or has been formerly
present, with all organic beings.

On certain Characters not blending.—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 dre paired, the .

young are not piebald nor of an intermediate tint, but are pure white or

of the ordinary grey colour : so it is when white and common collared 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 game, 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 thése colours mingled in
the same animal, but often all four colours in the same litter.” Additional
cases could be given, but this form of inheritance is very far from universal
even with respect to the most distinct colours. When turnspit dogs and ancon
sheep, both of which have dwarfed limbs, are crossed 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 invariably, happens that the offspring are

W Extract of a letter from Sir R. South American dogs, see Rengger,
Heron, 1838, given me by Mr. Yarrell. ‘Saiugethiere von Paraguay,’ s. 152:
With respect to mice, see ‘Annal. des but I saw in the Zoological Gardens
Se. Nat.’ tom. i, p. 180; and I have mongrels, from a similar cross, which
heard of other similar cases. For wete hairless, quite hairy, or hairy
turtle-doves, Boitard and Corbié, ‘Les in patches, that is, piebald with hair.
Pigeons,’ &c., p. 238. For the Game fowl, For crosses of Dorking and other fowls,
‘The Poultry Book, 1866, p.128. For see ‘Poultry Chronicle, vol. ii. p. 355.
crosses of tailless fowls, see Bechstein, About the crossed pigs, extract of letter
‘Naturges. Deutsch.” b. iii, s. 4038. from Sir R. Heron to Mr. Yarrell.
Bronn, ‘ Geschichte der Natur,’ b. ii. s. For other cases, see P, Lucas, ‘Héréd.
170, gives analogous facts with horses. Nat.,” tom. i. p. 212.

On the hairless condition of crossed

Cuap. XY. NOT BLENDING. 93

either perfectly furnished with these organs or are quite destitute of them.
According to Rengger, the hairless condition of the Paraguay dog is either
perfectly or not atall transmitted to its mongrel offspring ; but I have seen
one partial 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 beetwen 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 cocardeaw 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 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.’* In the succeeding generations raised from the
rough-leaved crossed seedlings, some glabrous plants appeared, showing
that the glabrous character, though incapable of blending with and modi-
fying the rough leaves, was all the time latent in this family of plants. The
numerous plants formerly referred 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 Verbascum :
and these colours were never blended, but the offspring bore either pure
white or pure yellow blossoms; the former in the larger proportion.”
Dr. Herbert raised many seedlings, as he informed me, from Swedish
turnips crossed by two other varieties, and these never produced flowers
of an intermediate tint, but always like one of their parents. I fertilised
the purple sweet-pea (Lathyrus odoratus), Which has a dark reddish-purple
standard-petal and violet-coloured wings and keel, with pollen of the painted-
lady sweet-pea, which has a pale cherry-coloured standard, and almost
white wings and keel; and from the same pod I twice raised plants per-
fectly resembling both sorts; the greater number resembling the father.
So perfect was the resemblance, that I should have thought there had

8 “Internat. Hort.and Bot. Congress from similar crosses in the genus Ver-
of London,’ 1866. baseum, With respect to the turnips,
19 «Bastarderzeugung,’ 8s. 307. Kél- see Herbert's ‘ Amaryllidaceer,’ 1837,
reuter (* Dritte Forisetszung,’ s. 34,39), —_p. 870.
however, obtained intermediate tints

94 ON CERTAIN CHARACTERS NOT BLENDING. — Cnap. xy.

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 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” raised numerous hybrids between the yellow
Linaria 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 between the organic
atoms of the same nature, apparently comes into play, for otherwise all parts
of the body would be equally intermediate in character. So again, when
the offspring of hybrids or mongrels, which are’ themselves nearly inter-
mediate in character, revert either wholly or by segments to their ancestors,
the principle of the affinity of 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 Geoffroy
St. Hilaire in regard to animals, that the transmission of characters without
fusion occurs most rarely when species are crossed; I know of one excep-
tion alone, namely, with the hybrids naturally produced between the
common and hooded crow (Corvus corone and cornix), which, however,
are closely allied species, differing in nothing except colour. Nor have I
met with any well-ascertained 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 super-
fostation,—that is, to the influence of two fathers. All the characters
above enumerated, which are transmitted in a perfect state to some of
the offspring and not to others,—such as distinct colours, nakedness of
skin, smoothness of leaves, absence of horns or tail, additional toes, pelo-
rism, dwarfed structure, &c.,—have all been known to appear suddenly in
individual animals and plants. From this fact, and from the several slight,
agerogated differences which distinguish domestic races and species from

20 ¢ Nouvelles Archives du Muséum, tom, i. p. 100.

CuaP, XV. CROSSING AS MODIFYING RACES, 95

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 Crossing.—We have hitherto chiefly considered the effects of
crossing in giving uniformity of character; we must now look
to an opposite result. There can be 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 Rey.
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 instance, the improved Essex owes its
excellence to repeated crosses with the N eapolitan, together pro-
bably with some infusion of Chinese blood! So with our British
sheep: almost all the races, except the Southdown, have been
largely crossed ; “ this, in fact, has been the history of our prin-
cipal breeds.”2 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

21 Richardson, ‘Pigs, 1847, pp. 37, see also an equally good article by Mr,
42; 8. Sidney’s edition of ‘ Youatt on Ch. Howard, in ‘ Gardener’s Chro
the Pig,’ 1860, p. 3. 1860, p. 320.

2 See Mr. W. C. Spooner’s excellent *3 “Gardener’s Chronicle,’ 1857, pp.
paper on Cross-Breeding, ‘ Journal 649, 652,

Royal Agricult. Soe.,’ vol, xx., part ii. ;

nicle,’

96 . ON CROSSING AS A CAUSE Cuar, XV,

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 carefully 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 Wurtemberg, 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.* 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 consti-
tute a distinct species, were undoubtedly formed” 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 which after six years’
culture presented an even sample, has been recorded on good
authority.”

Until quite 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 superstitious tenacity to the doctrine of purity
“of blood, believing it to be the ark in which alone true safety
“could be found.”* Nor was this conviction unreasonable:
when two distinct races are crossed, the offspring of the first
generation are generally nearly uniform in character; but even
this sometimes fails to be the case, especially with crossed dogs
and fowls, the young of which from the first are sometimes much

24 ¢ Bulletin de la Soc. d’Acclimat.,’ 25 «The Poultry Book,’ by W. B.
1862, tom. ix. p. 463. See also, for Tegetmeier, 1866, p. 58.
other cases, MM. Moll and Gayot, ‘ Du 27 *Gardener’s Chronicle, 1852, Pp.
Boouf,’ 1860, p. Xxxil. 765. :
25 «Poultry Chronicle,’ vol. ii, 1854, 28 Spooner, in ‘Journal Royal Agri-
p. 36. cult. Soce.,’ vol. xx., part il.

Cuap, XV. OF THE MODIFICATION OF RACES. 97

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
utterly useless; for though they may be themselves uniform in
character, when paired together they yield during many gene-
rations offspring astonishingly diversified. The breeder is driven
to despair, and concludes that he will never form an inter-
mediate race. But from the cases already given, and from
others which have been recorded; it appears that patience alone is
necessary ; as Mr. Spooner remarks, “nature opposes no barrier
to successful admixture; im 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
result will in most cases be obtained; but even then an occa-
sional reversion, or failure to keep true, may be expected. The
attempt, however, will assuredly fail if the conditions of life
be decidedly unfavourable to the characters of either parent-
breed.”

Although the grandchildren and succeeding generations of
cross-bred animals are generally variable in an extreme degree,
some curious exceptions to the rule have been observed, both
with crossed races and species. Thus Boitard and Corbié®
assert that from a Pouter and a Runt “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’! bred some bluish fowls from a black
Spanish cock and a Malay hen; and these remained true to
colour “generation after generation.” The Himalayan breed
of rabbits was certainly formed by crossing two sub-yarieties 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 ducks reared during
three generations were nearly uniform in character, being brown
with a white crescentic mark on the lower part of the breast,

29 See Colin’s ‘ Traité de Phys. Comp. 30 ‘Les Pigeons,’ p, 37,
des Animaux Domestiques,’ tom. ii. p. 31 Vol. i., 1854, p. 101,
536, where this subject is well treated.

VOL, IT. H

a ey
ee

98 ON OROSSING AS A CAUSE Cup, Xy,

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® 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® has given five cases of hybrids, in which the progeny
kept constant; and hybrids between Dianthus armeria and
deltoides 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
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 spectes probably came into play
at an early period in the formation of our present races. From
Riitimeyer’s observations 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
absorbed 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 hesitation 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

® * Cottage Gardener,’ 1856, p. 110. 33 « Bastarderzeugung,’ s. 993.

Cuap. XV. OF THE MODIFICATION OF RACES. - el]

itself; but it is now positively affirmed* that this 1s an error.
With plants which can be multiplied by buds and cuttings, hybri-
disation has done wonders, as with many kinds of Roses, Rhodo-
dendrons, Pelargoniums, Calceolarias, and Petunias. Nearly
all these plants can be propagated by seed; most of them
treely ; but extremely few or none come true by seed.

Some authors believe that crossing is the chief cause of varia-
bility,—that is, of the appearance of absolutely new characters.
Some have gone so far as to look at it as the sole cause; 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 pro-
bable ; 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 following
chapters, together with some remarks on Hybridism, will be
given in the nineteenth chapter.

34 Dr. Pigeaux, in * Bull. Soc. d’Acclimat.,’ tom. iii., July 1866, as quoted in
‘Annals and Mag. of Nat. Hist.,? 1867, vol. xx. p. 75.

100 CAUSES WHICH CHECK Cuap. 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, MELONS, AND
TOBACCO, RENDERED IN SOME DEGREE MUTUALLY STERILE — DOMESTICATION
ELIMINATES THE TENDENCY TO STERILITY NATURAL TO SPECIES WHEN CROSSED
— ON THE INCREASED FERTILITY OF UNCROSSED ANIMALS AND PLANTS FROM
DOMESTICATION AND CULTIVATION,

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 offspring, are almost invariably in some
degree sterile; and here there seems to exist a broad and in-
superable distinction between races and species. The import-
ance of this subject as bearing on the origin of species is
obvious; and we 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 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

1 ¢ Journal de Physiolog.,’ tom. ii., 1859, p. 385.

Cuap. XVI. THE CROSSING OF VARIETIES. 101

almost certainly have been observed. In investigating the
fertility of crossed varieties many sources of doubt occur.
Whenever the least trace of sterility between two plants,
however closely allied, was observed by Kolreuter, and more
especially by Giirtner, who counted the exact number of seed
in each capsule, the two forms were at once ranked as dis-
tinct species; and if this rule be followed, assuredly it will
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 méter se; but, sup-
posing 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 would
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 inter-
breeding, 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 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.,? 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, &e. 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?
remarks, “the Talavera wheat, from flowering much earlier than
any other kind, is sure to continue pure.” In different parts of

2 Dec. 1863, p. 484. 3 On the Varieties of Wheat, p. 66.

102 CAUSES WHICH CHECK Crap, XVI,

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
Sulivan, 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 aleo 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 species. In Paraguay the horses have
much freedom, and an excellent observer‘ 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® 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 Lincolnshires 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

* Rengger, ‘Saugethiere von Para~- and De Quatrefages, in ‘Bull. Soc.

guay,’ 8. 336. d’Acclimat.” tom, viii, July, 1861, p-
5 See a memoir by MM. Lherbette 312.

Cuap. XVI, THE CROSSING OF VARIETIES. 103

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.”° With
respect to fallow deer, which live in a semi-domesticated condi-
tion, Mr. Bennett” states that the dark and pale coloured herds,
which have long been kept together in the Forest of 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. Bartlett, 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 appeared to me
that the birds, though faithful to their marriage 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 England, 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;* yet all have

6 For the Norfolk sheep, see Mar-
shall’s ‘Rural Economy of Norfolk,’
vol. ii, p. 136. See Rev. L. Landt’s
‘Description of Faroe,’ p. 66. For the
ancon sheep, see ‘Phil. Transact.,’
1813, p. 90.

7 White’s ‘Nat. Hist. of Selbourne,’

edited by Bennett, p. 39. With respect
to the origin of the dark-coloured deer,
see ‘Some Account of English Deer
Parks,’ by E. P. Shirley, Esq.

8 «The Dovecote,’ by the Rev. E. 8.
Dixon, p. 155; Bechstein, ‘ Naturgesch.
Deutsehlands,’ Band iv., 1795, s. 17.

104 CAUSES WHICH CHECK Crap. XVI; °

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 experienced observers,
show that some domestic races are led by different habits of life
to keep to a certain extent separate, and that others prefer
coupling with their own kind, 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 racés, I know of
no well-ascertained case with animals. This fact, seeing the great differ-
ence in structure between some breeds of pigeons, fowls, pigs, dogs,
&e., 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 will not safely guide us in foretelling whether or not they will
breed together,—some closely allied species when crossed being utterly
sterile, and others which are extremely unlike being moderately fertile.
T have said that no case of sterility in crossed races rests on satisfactory |
evidence; but here is one which at first seems trustworthy. Mr. Youatt,°
and a better authority cannot be quoted, states, that formerly 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,” 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 noticed.
Moreover, supposing that Mr. Youatt had proved his case, it might be
argued that the sterility was wholly due to the two parent-breeds being
descended from primordially distinct species.

I will give a case with plants, to show how difficult it is to get sufli-
cient evidence. Mr. Sheriff, who has been so successful in the forma-
tion of new races of wheat, fertilised the Hopetoun with the Talavera;
in the first and second generations the produce was intermediate in cha-
racter, 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

9 ‘Cattle,’ p. 202.
10 Mr, J. Wilkinson, in ‘Remarks addressed to Sir J. Sebright,’ 1820, p. 38.
N * Gardener’s Chronicle,’ 1858, p. 771.

ees

Cuap. XVI. THE CROSSING OF VARIETIES. 105

varieties of wheat differ in any important character, it seems to me very
improbable that the sterility resuited, as Mr. Sheriff thought, from the
cross, but from some quite 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” with pollen of a tall maize having red seed;
and one head alone produced good seed, only five in number. Though
these plants are moncecious, 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 cross; and this,
considering that the plants are moncecious and abound with pollen, and
are well known generally 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.* No one, I believe, has
hitherto suspected that these varieties of maize are distinct species; 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 hybrids; others can be crossed with
extreme difficulty, but the hybrids when produced are moderately fertile.
T 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 hybrids. ,

The following case is much more remarkable, and evidently perplexed
Girtner, 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 con-
sisted in crossing white and yellow varieties of both V. lychnitis and V.
biattaria 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 Girtner actually raised in the case of both species
one variety from the seed of the other. Now in two of his works" he
distinctly asserts that crosses between similarly-coloured flowers yield
more seed than between dissimilarly-coloured ; so that the yellow-flowered
variety of either species (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

12 ¢ . i ;
Bastarderzeugung,’ s. 87, 169, 144 ¢Kenntniss der Befruchtung,’ s.
See also the Table at the end of 137; ‘Bastarderzeugung, s. 92, 181.
volume. On raising the two varieties from seed

13 « Bastarderzeugung,’ s. 87, 577. see 8, 307.

106 CAUSES WHICH CHECK Cap, XVI,

end of his volume. In one instance he gives® the following details; but
must premise that Gartner, to avoid exaggerating the degree of sterility in
his crosses, always compares the maaimum number obtained from a crogg
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 Giirtner’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 variety 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 castration 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 Géartner 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 fertilised by the white and
yellow varieties of -V. blattaria, for it is probable 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 re-
peated some of Gartner’s experiments on distinct species, but obtained only
fluctuating results; some confirmatory, but the greater number contradic-
tory; nevertheless these seem hardly sufficient to overthrow the conclu-
sions arrived at by Gartner from experiments tried on a much larger scale.
In the second place Mr. Scott experimented on the relative fertility of
unions between similarly and dissimilarly-coloured varieties of the same
Species. Thus he fertilised six flowers of the yellow variety of V. lychnitis
by its own pollen, and obtained six capsules, and calling, for the sake of
having a standard of comparison, the average number of good seed in
each one hundred, he found that this same yellow variety, when 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 pro-
portion of 100 to 79. So that in every case the unions 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 similarly-coloured unions yielded thirty-five good

1 ‘ Bastarderzeugung,’ s. 216.

Cuap. XVI. THE CROSSING OF VARIETIES. 107
capsules ; whilst thirty-five dissimilarly-coloured unions yielded only twenty-
six good capsules. Besides the foregoing experiments, the purple V. phe-
niceum was crossed by a rose-coloured and a white variety of the same
species; these two varieties were also crossed together, and these several
unions yielded less seed than V. pheniceum 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.”°

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. The following case
is worth giving, partly to show how difficult it is to avoid error. Dr.
Herbert” has remarked that variously-coloured double varieties of the
hollyhock (Althea 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 Canterbury
has given me a more striking case; he saved seed from a great bed of
twenty-four named varieties planted in closely adjoining rows, and each
variety reproduced itself truly with only sometimes a shade of difference in
tint. Now in the hollyhock the pollen, 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 covered with pollen incessantly fly from plant to plant, it
would appear that adjoining varieties could not escape being crossed. As,
however, this does not occur, it appeared to me probable that the pollen

16 The following facts, given by
Ko6lreuter in his ‘ Dritte Fortsetzung,’
s. 84, 39, appear at first sight strongly
to confirm Mr. Scott’s and Gartner’s
statements; and to a certain limited
extent they do so. Koélreuter asserts,
from innumerable observations, that in-
sects incessantly carry pollen from one
species and variety of Verbascum to
another; and I can confirm this asser-
tion; yet he found that the white and
yellow varieties of Verbascum lychnitis
often grew wild mingled together : more-
over, he cultivated these two varieties
in considerable numbers during four
years in his garden, and they kept true
by seed; but when he crossed them,
they produced flowers of an _ inter-
mediate tint. Hence it might have
been thought that both varieties must
have a stronger elective affinity for the
pollen of their own variety than for
that of the other; this elective affinity,

I may add, of each species for its own
pollen (Kolreuter, ‘Dritte Forts.,’ s. 39,
and Girtner, ‘ Bastarderz.,’ passim)
being a perfectly well - ascertained
power. But the force of the foregoing
facts is much lessened by Giartner’s
numerous experiments, for, differently
from Kéolreuter, he never once got
(‘ Bastarderz.,’ s. 307) an intermediate
tint when he crossed the yellow and
white flowered varieties of Verbascum.
So that the fact of the white and yellow
varieties keeping true to their colour by
seed does not prove that they were not
mutually fertilised by the pollen carried
by insects from one to the other.

17 ‘Amaryllidacee,’ 1837, p. 366,
Gartner has made a similar observa-
tion.

18 Kélreuter first observed this fact.
‘Mém. de 1’ Acad. de St. Petersburg,’ vol.
iii. p. 197. See also C. K. Sprengel,
‘Das Entdeckte Geheimniss,’ s. 345.

108 CAUSES WHICH CHECK

Cap, XVI.

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 it is difficult even to cross them artificially. Whether thig
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 moneecious forms,
which do not require, and consequently have not been injured by, castra-
tion. Girou de Buzareingues crossed what he designates three varieties
of gourd,” and asserts that their mutual fertilisation is less easy in propor-
tion to the difference which they present. I am aware how imperfectly the
forms in this group were until recently known; but Sageret° 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.?
Sageret™ has observed that certain melons have a greater tendency, what-
ever 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 Cit-
rullus, which, as they could be artificially crossed with perfect facility and
produced fertile offspring, are ranked as varieties; but these forms when
not artificially 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 tobacco2® which were
reciprocally crossed, and the offspring were intermediate in character and
as fertile as their parents: from this fact Kolreuter 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
N. 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.* So that the sexual

19 Namely, Barbarines, Pastissons,
Giraumous : ‘ Annal. des Se. Nat.,’ tom.
Xxx., 1833, pp. 398 and 405.

20 “Mémoire sur les Cucurbitaces,’
1826, pp. 46, 55.

1 « Annales des Se. Nat.,’ 4th series,
tom. vi. M. Naudin considers these
forms as undoubtedly varieties of Cu-
curbita pepo.

22 «Mém. Cucurb.,’ p. 8.

3 « Zweite Forts.,’ s. 53, namely, Ni-
cotiana major vulgaris; (2) perennis ;

(3) Transylvanica; (4) a sub-var. of
the last ; (5) major latifol. fl. alb.

24 Kélreuter was so much struck with
this fact that he suspected that a little
pollen of N. glutinosa in one of his ex-
periments might have accidentally got
mingled with that of var. perennis, and
thus aided its fertilising power. But
we now know conclusively from Gartner
(‘Bastarderz.,’ s. 34, 43) that two kinds
of pollen never act conjointly on a third
species; still less will the pollen of @

Cuap, XVI. THE CROSSING OF VARIETIES. 109

capacity of this one variety has certainly been in some degree modified,
so as to approach in nature that of NV. glutinosa.”

These facts with respect to plants show that im some few
cases certain varieties have had their sexual powers so far
modified, that they cross together less readily and yield less
seed than other varieties of the same species. We shall pre-
sently 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 eliminates the tendency to Sterility which is general
with Species when crossed.

This hypothesis was first propounded by Pallas,” 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 an-
ciently domesticated varieties, when crossed with a distinct
species, with that of the wild parent-species when similarly
crossed. No one has compared, for instance, the fertility of
Gallus bankiva and of the domestieated fowl, when crossed
with a distinct species of Gallus or Phasianus; and the

distinct species, mingled with a plant’s
own pollen, if the latter be present in
sufficient quantity, have any effect. The
sole effect of mingling two kinds of
pollen is to produce in the same capsule
seeds which yield plants, some taking
after the one and some after the other
parent.

25 Mr. Scott has made some observa-
tions on the absolute sterility of a purple
and white primrose (Primula vulgaris)
when fertilised by pollen from the
common primrose (‘ Journal of Proc. of
Linn. Soe.,’ vol. vili., 1864, p. 98); but
these observations require confirmation.
Traised anumber of purple-flowered long-
styled seedlings fromseed kindly sent me
by Mr. Scott, and, though they were all
in some degree sterile, they were much
more fertile with pollen taken from the
common primrose than with their own

pollen. Mr. Scott has likewise de-
scribed a red equal-styled cowslip
(P. veris, idem, p. 106), which was
found by him to be highly sterile when
crossed with the common cowslip;
but this was not the case with several
equal-styled red seedlings raised by me
from his plant. This variety of the
cowslip presents the remarkable pe-
culiarity of combining male organs in
every respect like those of the short-
styled form, with female organs resem-
bling in function and partly in structure
those of the long-styled form ; so that
we have the singular anomaly of the
two forms combined in the same flower.
Hence it is not surprising that these
flowers should be spontaneously self-
fertile in a high degree.

76 ‘Act, Acad. St. Petersburg,’ 1780,
part ii., pp. 84, 100.

110 DOMESTICATION ELIMINATES STERILITY. Cuap, XVJ

experiment would in all cases be surrounded by many diff.
culties. Dureau de la Malle, who has so closely studied classical
literature, states” 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 is given
by M. Groenland,* namely, that plants, known from their inter-
mediate character and sterility to be hybrids between Aigilops
and wheat, have perpetuated themselves under culture sgince
1857, with a rapid but varying increase of fertility in each genera-
tion. In the fourth generation the plants, still retaining their
intermediate character, had become as fertile as common
cultivated wheat.

The indirect evidence in favour of the Pallasian doctrine
appears to me to be extremely strong. In the earlier 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 belong to at
least two specific types, S. scrofa and Indicus, 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.
Nevertheless 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 doctrine that long-continued
domestication tends to eliminate that sterility which is natural
to species when crossed in their aboriginal state.

27 * Annales des Sc. Nat.,’ tom. xxi. (1st series), p. 61.
78 ‘Bull. Bot. Soc. de France,’ Dec. 27th, 1861, tom. viii. p. 612.

Cuap, XVI. INCREASED FERTILITY FROM DOMESTICATION, 111

On increased Fertility from Domestication and Cultivation.

Increased fertility from domestication, without any refer-
ence to crossing, may be here briefly considered. This subject
bears indirectly on two or three points connected with the mo-
dification of organic beings. As Buffon long ago remarked,”
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 supplied
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
generally 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 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 affects the fertility
even of the same individual: thus sheep, which on mountains
never produce more than one lamb at a birth, when brought

9 Quoted by Isid. Geoffroy St.

; the present subject has appeared in Mr.
Hilaire, ‘Hist. Naturelle Générale,’

Herbert Spencer’s ‘Principles of Bio-

tom. iii. p. 476. Since this MS. hag logy,’ vol. ii., 1867, p. 457 et seq.
been sent to press a full discussion on

112 INCREASED FERTILITY Cuap. XVI,

down to lowland pastures frequently bear twins. This differ-
ence apparently is not due to the cold of the higher land, for
sheep and other domestic animals are said to be extremely
prolific in Lapland. 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.*°

Birds offer still better evidence of increased fertility from domestication :
the hen of the wild Gallus bankiva lays from six to ten eggs, a number
which would be thought nothing of with the domestic 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, C. livia, I know not; but the more
thoroughly domesticated 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.*!

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

30 For cats and dogs, &c., see. Bel- ‘British Birds,’ vol. v. p. 87; and ‘ Die
lingeri, in ‘Annal. des Sc. Nat.” 2nd Enten,’ s. 87. For wild geese, L. Lloyd,
series, Zoolog., tom. xii. p. 155. For ‘Scandinavian Adventures,’ vol. ii.
ferrets, Bechstein, ‘ Naturgeschichte 1854, p. 413; and for tame geese,
Deutschlands,’ Band i, 1801, s. 786, ‘Ornamental Poultry,’ by Rev. E. S$.
795. For rabbits, ditto, s. 1123, 1131; Dixon, p. 189. On the breeding of
and Bronn’s ‘Geschichte der Natur, pigeons, Pistor, ‘Das Ganze der Tau-
B. ii. s. 99. For mountain sheep, ditto, | benzucht,’ 1831, s. 46; and Boitard and
s. 102. For the fertility of the wild Corbié, ‘Les Pigeons; p. 158. With
sow, sce Bechstein’s ‘Naturgesch. respect to peacocks, according to Tem-
Deutschlands,’ B. i., 1801, s. 534; for minck (‘ Hist. Nat. Gén, des Pigeons,’
the domestic pig, Sidney’s edit. of &c., 1813, tom. ii. p. 41), the hen lays
Youatt on the Pig, 1860, p. 62. With in India even as many as twenty eggs;
respect to Lapland, see Acerbi's‘Travels but according to Jerdon and another
to the North Cape,’ Eng. translat., vol.ii. | writer (quoted in Tegetmeier’s ‘Poultry
p. 222. About the Highland cows, see Book,’ 1866, pp. 280, 282), she there lays
Hoge on Sheep, p. 263. ~ only from four to nine or ten eggs: in

31 For the eggs of Gallus bankiva, see England she is said, in the ‘Poultry
Blyth, in ‘Annals and Mag. of Nat. Book,’ to lay five or six, but another
Hist.,’ 2nd series, vol. i., 1848, p. 456. ria says from eight to twelve eggs:

For wild and tame ducks, Macgillivray,

ss.

CHap, XVI. FROM DOMESTICATION. 113

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 Aspa-
ragus in comparison with the wild plant is enormous. No doubt many
highly cultivated plants, such as pears, pineapples, bananas, sugar-cane,
&e., 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
asparagus, which are not valued for their prolificacy, selection
can have played only a subordinate part; and their increased
fertility must be attributed to the more favourable conditions of
life under which they have long existed.

VOL. pf Te I

114 GOOD FROM CROSSING. Car. XVII,

CHAPTER XVII.

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

DEFINITION OF CLOSE INTERBREEDING — AUGMENTATION OF MORBID TENDENCIES —
GENERAL EVIDENCE ON THE GOOD EFFECTS DERIVED FROM CROSSING, AND ON THE
EVIL EFFECTS FROM CLOSE INTERBREEDING — CATTLE, CLOSELY INTERBRED ; HALF-
WILD CATTLE LONG KEPT IN THE SAME PARKS — SHEEP — FALLOW-DEER — pogs —
RABBITS — PIGS — MAN, ORIGIN OF HIS ABHORRENCE OF INCESTUOUS MARRIAGES
— FOWLS — PIGEONS — HIVE-BEES — PLANTS, GENERAL CONSIDERATIONS ON THE
BENEFITS DERIVED FROM CROSSING — MELONS, FRUIT-TREES, PEAS, CABBAGES,
WHEAT, AND FOREST-TREES — ON THE-INCREASED SIZE OF HYBRID PLANTS, NoT
EXCLUSIVELY DUE TO THEIR STERILITY — ON CERTAIN PLANTS WHICH EITHER
NORMALLY OR ABNORMALLY ARE SELF-IMPOTENT, BUT ARE FERTILE, BOTH ON THE
MALE AND FEMALE SIDE, WHEN CROSSED WITH DISTINCT INDIVIDUALS EITHER OF
THE SAME OR ANOTHER SPECIES — CONCLUSION. :

THE gain in constitutional vigour, derived from: an occasional
cross between individuals of the same variety, but belonging to
distinct families, or between distinct varieties, 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, inasmuch 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 invariably
follow a cross are from the first manifest. It should, however,
be clearly understood that the advantage of close interbreeding,
as far as the retention of character is concerned, is indisput-
able, and often outweighs the evil of a slight loss of constitu-
tional vigour. Jn relation to the subject of domestication, the
whole question is of some importance, as too close interbreeding
interferes with the improvement of old races, and especially
with the formation of new ones. It is important as indirectly
bearing on Hybridism ; and perhaps on the extinction of species,
When any form has become so rare that only a few individuals

.

Cuap. XVII. EVIL FROM INTERBREEDING, 115

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 additional
vigour and fertility be thus gained, the crossed offspring will
multiply and prevail, and the ultimate result will be far greater
than otherwise would have occurred. 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 “ breeding 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
generations, 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 con-
sequences of close interbreeding carried on for too long a time,
are, as 1s generally believed, loss of size, constitutional vigour,
and fertility, sometimes accompanied by a tendency to mal-
formation. Manifest evil does not usually follow from pairing
the nearest relations for two, three, or even four genera-
tions; but several causes interfere with our detecting the evil
—such as the deterioration being very gradual, and the diffi-
culty of distinguishing between such direct evil and the inevit-
able 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 hag not been any very
close interbreeding, is almost invariably at once conspicuous.
There is reason to believe, and this was the opinion of that most
experienced observer Sir J. Sebright,! that the evil effects of
close interbreeding may be checked by the related individuals

1 “The Art of Improving the Breed, &e.,’ 1809, p. 16.
12

116 GOOD FROM CROSSING. Cuap, XVII,

being separated during a few generations and exposed to different
conditions of life.

That evil directly follows from any degree of close inter-
breeding has been denied by many persons; but rarely by any
practical breeder ; and never, as far as I know, by one who lias
largely bred animals which propagate 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 constitu.
tion, 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, induces sterility; and _ this
indicates something quite distinct from the augmentation of
morbid tendencies common to both parents. The evidence
immediately to be given convinees me that it is a great law of
nature, that all organic beings profit from an occasional cross
with individuals not closely related to them in blood; and
that, on the other hand, long-continued close interbreeding is
injurious.

Various general considerations have had much influence in
leading me to this conclusion ; but the reader will probably rely
more on special facts and opinions. The authority of experi-
enced observers, even when they do not advance the grounds of
their belief, is of some little value. Now almost all men who
have bred many kinds of animals and have written on the
subject, such as Sir J. Sebright, Andrew Knight, &c.,? have
expressed the strongest conviction on the impossibility of long-
continued close interbreeding. Those who have compiled 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,
who has written the most able treatise on this subject which
I have met with, concurs; and as I shall have to quote from

* For Andrew Knight, see A. Walker, on ‘Intermarriage,’ 1838, p. 227. Sir J.
Sebright’s Treatise has just been quoted,

-

Cuap. XVI. EVIL FROM INTERBREEDING. 117

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.

Kyidence of the evil effects of close interbreeding can most
readily be acquired in the case of animals, such as fowls,
pigeons, &ec., 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 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 unwilling, at the risk, in their opinion, of deterioration,
to make a cross. The purchase of a first-rate bird of another
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 crossing, are driven
after a time to take this step.

Another general consideration which has had great influence
on my mind is, that with all hermaphrodite animals and plants,
which it might have been thought would have perpetually ferti-
lised 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 inevit-
ably lead to an occasional cross between one hermaphrodite 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 interbreeding
may be long carried on, advantageously with respect to external characters
and with no manifestly apparent evil as far as constitution 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 Long-
horns, which were closely interbred for a long period, has often been

118 GOOD FROM CROSSING. Cuap, XVII.

quoted; yet Youatt says® the breed “had acquired a delicacy of consti-
tution inconsistent with common management,” and “ the propagation of
the species was not always certain.” But the Shorthorns offer the most
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, granddaughter, and
great-granddaughter; so that the produce of this last union, or the
great-great-granddaughter, had 15-16ths, or 93°75 per cent. of the blood
of Favourite in her veins. This cow was matched with the bull Well-
ington, having 62°5 per cent. of Favourite blood in his veins, and pro-
duced Clarissa; Clarissa was matched with the bull Lancaster, having
68°75 of the same blood, and she yielded valuable offspring. N. evertheless
Collings, who reared these animals, 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 cele-
brated 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. Mx. Bates’s own view, as given
by a celebrated breeder,’ was, that “to breed in and in from a bad stock
was ruin and devastation; yet that the practice may be safely followed
within certain limits when the parents so related are descended from first-
rate animals.” We thus see that there has been extremely close inter-
breeding with Shorthorns; but Nathusius, 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 his whole life. From this study and
his own experience, he concludes that close interbreeding is necessary
to ennoble the stock; but that in effecting this the greatest care is
necessary, on account of the tendency to infertility and weakness. It
may be added, that another high authority ® asserts that many more calves
are born cripples from Shorthorns than from other and less closely inter-
bred races of cattle.

Although by carefully selecting the best animals (as Nature effectually
does by the law of battle) close interbreeding may be 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 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

3 <Cattle,’ p. 199. Australia, 1865.

4 Nathusius, ‘ Ueber Shorthorn Rind- 5 Mr. Willoughby Wood, in ‘Gar-
vieh,’ 1857, s. 71: see also ‘Gardener’s _dener’s Chronicle,’ 1855, p. 411; and
Chronicle,’ 1860, p. 270. Many analo- 1860, 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. Macknight ‘ Rindvieh, s. 72-77.
and Dr. H. Madden, ‘On the True 6 Mr. Wright, ‘Journal of Royal
Principles of Breeding;’ Melbourne, Agricult. Soe.,’ vol. vii., 1846, p. 204.

CuaP. XVII. EVIL FROM INTERBREEDING. 119

parts of England to be slaughtered;* 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 probably
for 400 or 500 years, or even for a longer period, have been advanced by
Culley and others as a case of long-continued interbreeding 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.* The agent, Mr. Hardy, estimates (in a letter to me, 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 Tankerville
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 following account of
the wild cattle kept in the Duke’s park in Lanarkshire, 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 unenclosed country
like Paraguay there must be some crossing between the different herds,
yet even there the inhabitants believe that the occasional introduc-
tion of animals from distant localities is necessary to prevent “ degene-
ration 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 Riitimeyer has shown that they are almost cer-
tainly the descendants of the gigantic Bos primigenius. 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 relations 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

Fa pte ARIES) Leica i cs LO MoO T AS

7 Youatt on Cattle, p. 202,
8 Report British Assoc., Zoolog. Sect., 1838.
® Azara, ‘Quadrupédes du Paraguay, tom. ii. pp. 354, 368.

120 GOOD FROM CROSSING. CHAP, XVII,

of experience has convinced him that when two nearly related animals
are quite sound in constitution, in-and-in breeding does not induce dege-
neracy; 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. Nevertheless,
most great breeders of sheep have protested against close interbreeding
prolonged for too great a length of time." The most celebrated of recent
breeders, Jonas Webb, kept five separate families to work on, thus “ retain-
ing the requisite distance of relationship between the sexes.”

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 advantage in judicious cross-breeding, especially
when the male is larger than the female. A former celebrated breeder,
Lord Somerville, distinctly states that his half-breeds from Ryelands and
Spanish sheep were larger animals than either the pure Ryelands or pure
Spanish sheep." ; :

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 dama) kept in them; but on inquiry I find that it is a common
practice to infuse new blood by procuring bucks from other parks.
Mr. Shirley,"* who has carefully studied the management of deer, admits
that in some parks there has been no admixture 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 disadvantagé 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 intro-
“ duction 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 removing 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 indecd 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

10 For the case of the Messrs. Brown, and Husbandry,’ p. 6. Mr. Spooner, in
see ‘Gard. Chronicle,’ 1855, p. 26. For ‘Journal of Royal Agricult. Soe. of
the Foscote flock, ‘Gard. Chron.,’ 1860, | England,’ vol. xx. part ii. See also an
p. 416. For the Naz flock, ‘Bull. dela excellent paper on the same subject

Soc. d’Acclimat.,’ 1860, p. 477. in ‘Gard. Chronicle,’ 1860, p. 321, by
11 Nathusius, ‘Rindvieh, gs. 65; Mr. Charles Howard.

Youatt on Sheep, p. 495. 14 *Some Account of English Deer
2 “Gard. Chronicle,’ 1861, p. 631. Parks,’ by Evelyn P. Shirley, 1867.

13 Lord Somerville, ‘Facts on Sheep

——

Cuap. XVI. EVIL FROM INTERBREEDING. 121

son, and sometimes even from brothers and sisters. Sir J. Sebright,
however, declares,” 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 enlarge-
ment 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 implies 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 individuals 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 constitu-
tion; but I do not pretend that these effects ought to be wholly attributed
to close interbreeding. <A great judge of rabbits” 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 barren or bad mothers.” Again: “ Very
long-eared bucks will also sometimes prove barren.” These highly-bred
rabbits often desert their young, so that itis 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 preserved.” Mr. Fisher
Hobbs, the raiser of the celebrated Improved Essex breed, divided his
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.” 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 '* 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 pro-
duced few that lived; and of the latter many were idiotic, without sense

15 «The Artof Improving the Breed,’ 7 Sidney’s edit, of Youatt on the Pig,
&e., p. 13. With respect to Scotch 1860, p. 30; p. 33, quotation from Mr.
deer-hounds, see Scrope’s ‘Art of Deer Druce; p. 29, on Lord Western’s case.
Stalking,’ pp. 350-353. 18 * Journal of Royal Agricult. Soc. of

16 ‘Cottage Gardener,’ 1861, p. 327. England,’ 1846, vol. vii. p, 205. :

122

GOOD FROM CROSSING,

Cuap, XVII,

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 litter 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.

Nathusius gives” an analogous and even. more striking case: he im-
ported from England a pregnant sow of the large Yorkshire breed, and
bred the product closely in-and-in for three generations: the result wag
unfavourable, as the young were weak in constitution, with impaired
fertility. One of the latest sows, which he esteemed a good animal, pro-
duced, 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 con-
stitution and quicker growth; but for me, who sell a great 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! Mr. Tylor” has shown

19 ‘Ueber Rindvieh,’ &c., s. 78.

#0 Sidney on the Pig, p. 36. See
also note, p. 34. Also Richardson on
the Pig, 1847, p. 26.

21 Dr. Dally has published an excel-
lent article (translated in the ‘ Anthro-
polog. Review,’ May, 1864, p. 65),
criticising all writers who have main-
tained that evil follows from con-
Ssanguineous marriages. No doubt on
this side of the question many advocates

have injured their cause by inaccu-
racies : thus it has been stated (Devay,
‘Du Danger des Mariages,’ &c., 1862,
p. 141) that the marriages of cousins
have been prohibited by the legislature
of Ohio; but I have been assured, in
answer to inquiries made in the United
States, that this statement is a mere
fable.

2 See his most interesting work on the
‘Early History of Man,’ 1805, chap. x.

Cuap. XVII. EVIL FROM INTERBREEDING. 123

that with widely different races, in the most distant quarters of
the world, marriages between 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” by Mr. W. Adam,
and formerly in 1828 by Hofacker. 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 apparent anomalies in the
prohibition not extending equally to the relations on both the
male and female side. He admits, however, that other causes,
such as the extension of friendly alliances, may have come into
play. Mr. W. Adam, on the other hand, concludes that related
marriages are prohibited and viewed 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 of Australia and South
America,2* 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 ascertained, 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 become jealous of their sons and expel
them, or whether any inherited instinctive feeling, irom 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 selec-
tion, and thus might become instinctive; for those individuals
which had an innate preference of this kind would increase in
number. It seems more probable, that degraded savages should

*3 On Consanguinity in Marriage, in 24 Sir G. Grey’s ‘Journal of Expe-
the ‘Fortnightly Review,’ 1865, p.710; ditions into Australia,’ vol. il. p. 243;
Hofacker, ‘Ueber die Eigenschaften, | and Dobrizhofier, ‘On the Abipones of
&e, South America,’

124 GOOD FROM CROSSING. Cuap. XVII.

thus unconsciously have acquired their dislike and even abhor-
rence of incestuous marriages, rather than that they should have
discovered by reasoning and observation the evil results. The
abhorrence occasionally failing 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 sympathies. In the case of man, the question whe-
ther evil follows from close interbreeding will probably never
be answered by direct evidence, as he propagates his kind go
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 argument of considerable weight; 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 autho-
rities could be given against too close interbreeding. Sir J. Sebright posi-
tively asserts that he made many trials, and that hig fowls, when thus
treated, became long in the legs, small in the body, and bad. breeders.”

He produced the famous Sebright Bantams by complicated crosses, and by
breeding in-and-in; and since his time there has been much close inter-

Pilemetiein cosh a. ie ea
*5 «The Art of Improving the Breed,’ Poultry Book,’ by Tegetmeier, 1866, p.
Ms hs 135, with respect to the extent to which
76 <The Poultry Book,’ by W. B, cock-fighters found that they could
Tegetmeier, 1866, p. 245. venture to breed in-and-in, viz., occa-
7 *Journal Royal Agricult, Soce.,’ sionally a hen with her own son; ‘ but
1846, vol. vii. p. 205; see also Ferguson they were cautious not to repeat the
on the Fowl, pp. 83, 317; see also‘The —in-and-in breeding.”

Caap, XVII. EVIL FROM INTERBREEDING. 125

weight. Mr. Clark does not seem to have bred from brothers and sisters,
which is the most injurious 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.”

An experienced writer” 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 crossing to
“* prevent deterioration.” ”

We thus see that there is almost complete unanimity with poultry-
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 other hand, it is a generally
received opinion that cross-bred chickens are the hardiest and most easily
reared. Mr. Tegetmeier, who has carefully attended to poultry of all
breeds, says” that Dorking hens, allowed to run with Houdan or Crevecceur
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 con-
siderably 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.”* ‘To this subject of the increased size of hybrids I
shall presently return.

With Piyeons, breeders are unanimous, as previously stated, that it is
absolutely indispensable, notwithstanding the trouble and expense thus
caused, occasionally to cross their much-prized birds with individuals of
another strain, but belonging, of course, to the same variety. It deserves

28 «The Poultry Book, by W. B. 81 «The Poultry Chronicle,’ vol, i. p.
Tegetmeier, 1866, p. 79. 89.

29 «The Poultry Chronicle,’ 1854, vol. 2 «The Poultry Book,’ 1866, p- 210.
i. p. 43. 33 Tbid. 1866, p. 167; and * Poultry

0 *The Poultry Book,’ by W. B. Chronicle,’ vol. iii, 1855, p. 15,
Tegetmeier, 1866, p. 79.

126 GOOD FROM CROSSING. Cuap. XVII,

notice that, when large size is one of the desired characters, as with
pouters,* the evil effects of close interbreeding 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 eges have
generally to be hatched under foster-mothers. Although these highly-
prized birds have invariably been subjected to much close interbreeding,
yet their extreme delicacy of constitution cannot perhaps be thus fully
explained. Mr. Yarrell informed me that Sir J. Sebright continued closely
interbreeding some owl-pigeons, until from their extreme sterility he ag
nearly as possible lost the whole family. Mr. Brent® 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 +e of trumpeter’s
blood ; but then the experiment failed, for “ breeding go close stopped re-
production.” The experienced Neumeister also asserts that the offspring
from dovecotes and various other breeds are “ generally very fertile and
hardy birds:” so again, MM. Boitard and Corbié, after forty-five years’
experience, recommend persons to cross their breeds for amusement; for,
if they fail to make interesting 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, because 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 offspring 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 shown® that this instinct
does not apply to drones, which are permitted to enter any hive; so that
there is no @ priori improbability of a queen receiving a foreign drone.
The fact of the union 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 ata distance
of from one to three and a half miles.”

34 « A Treatise on Fancy Pigeons,’ by 37 “Leg Pigeons,’ 1824, p. 35.

J. M. Eaton, p. 56. 38 «Proc, Entomolog. Soc.,’ Aug. 6th,
35 «The Pigeon Book,’ p. 46. 1860, p. 126.
36 «Das Ganze der Taubenzucht,’ 39 « Journal of Horticulture,’ 1861, pp.

1837, s. 18. 39, 77, 158; and 1864, p. 206.

Cuap, XVIL EVIL FROM INTERBREEDING. 127

Plants.

When a single plant of a new species is introduced into any country,
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 flowers with
their own pollen during several generations. But we shall presently see
that certain plants, either normally or abnormally, are more or less sterile,
even in the first generation, when fertilised by their own pollen. Although
nothing is directly known on the evil effects of long-continued close inter-
breeding 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, states *® that he has many times observed good effects from

his step, especially with exotic genera, of which the fertility is somewhat
impaired, such as Passiflora, Lobelia, and Fuchsia. Herbert also says,"
“I am inclined to think that I have derived advantage from impreg-
“nating 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 hag
ascertained that crossed offspring are more vigorous and robust than their
parents.”

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 light will thus also be thrown on
the fact that flowers are invariably constructed so as to permit, or favour,
or necessitate the union of two individuals. We shall clearly understand
why monescious and dicecious,—why dimorphic and trimorphic plants exist,
and many other such cases. The plan which I have followed in my expe-
riments 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 insects; 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 experiments, the crossed plants yielded much
more seed than the self-fertilised plants; and I have never seen the

eee ed eo Py 73

* Beitraige zur Kenntniss der Befruchtung,’ 1844, s. 366.
41 ¢ Amaryllidacese,’ p. 371,

* * De la Fécondation,’ 2nd edit., 1862, p. 79.

128 GOOD FROM CROSSING. Cuap. XVII,

reversed case. The self-fertilised and crossed seeds thus obtained were
allowed to germinate in the same glass vessel on damp sand; and as the
seeds successively germinated, they were planted in pairs on opposite
sides of the same pot, with a superficial partition between them, and were
placed so as to be 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, but in every
case have taken all the precautions which I could think of, so that the
two lots should be 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, Lupinus, Lobelia, Lactuca, Dianthus, Myosotis, Pe-
tunia, Linaria, Calceolaria, Mimulus, and Ipomcea, 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 Ipomea 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 opposed 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 luteus were fertilised with their own
pollen, and others were crossed with pollen from distinct plants growing
in the same pot. The seeds after germinating were thickly planted
on opposite sides of a pot. The seedlmgs were at first equal in height;
but when the young crossed plants were exactly half an inch, the self-

Crap, XVIL EVIL FROM INTERBREEDING. 129

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 vigorous than the uncrossed, and flowered before
them ; they produced 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 Ipomcea during their whole
growth, I could not have believed it possible, that a difference 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 pro-
duced. This, under a physiological point of view, is a most remarkable
phenomenon.

With respect to the benefit derived from crossing distinct varieties,
plenty of evidence has been published. Sageret * 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: * “TJ have this summer met with better success in my culti-
“vation of melons, in an unprotected state, from the seeds of hybrids
“(z.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 “ believed that his seedlings from crossed varieties of
the apple exhibited increased vigour and luxuriance; and M. Chevreul 4
alludes to the extreme vigour of some of the crossed fruit-trees raised by
Sageret.

By crossing reciprocally the tallest and shortest peas, Knight *7 says,
“Thad in this experiment a striking instance of the stimulative effects
“of crossing the breeds; 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 between four distinct kinds; and the
plants thus raised were extraordinarily vigorous, being in each case from

one to two or three feet taller than the parent-forms growing close along-
side them. |
id agg EE mage

43 “Mémoire sur leg Cucurbitacées,’ 46 ¢ Annal. des Sc. Nat.,’ 3rd series,
pp. 36, 28, 30. Bot., tom. vi. p. 189.

* London's 7 Gard: Was sali: ” 767 eh Gash ical Transactions Fae
1832, p. 52. p. 200.

4 ¢ Transact. Hort. Soc.,’ vol. i, p. 25,
VOL. II. K

130 GOOD FROM CROSSING. Cuap. XVII,

Wiegmann ** made many crosses between several varieties of cabba ge;
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 mongrels displayed an infinite
diversity of character; “ But the most remarkable circumstance was,
“ that, while all the ails 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 Society “ 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,®° 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 different soils and situations.”

Here is a remarkable case: M. Clotzsch* crossed Pinus sylvestris and
nigricans, Quercus robur and pedunculata, Alnus glutinosa and incana,
Ulmus campestris and effusa ; and the cross-fertilised seeds, as well as seeds
of the pure parent-trees, were all sown at 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, often gain in size
and constitutional vigour, is certain. It would be superfluous to quote
any facts; for all experimenters, Kolreuter, Gartner, Herbert, Sageret,
Lecoq, and Naudin, have been struck with the wonderful vigour, height,
size, tenacity of life, precocity, and hardiness of their hybrid productions.
Gartner’ sums up his conviction on this head in the strongest terms.
Kolreuter * gives numerous precise measurements of the weight and height
of his hybrids in comparison with measurements of both parent-forms ;
and speaks with astonishment of their “ statwra portentosa,” their “ ambitus
vastissimus ac altitudo valde conspicua.” Some exceptions to the rule in the
case of very sterile hybrids have, however, been noticed by Gartner and

48 ‘Ueber die Bastarderzeugung,’ 1828, vol. ii., 1855, p. 827.

s. 82, 33. For Mr. Chaundy’s case, see 52 Gartner, ‘ Bastarderzeugung,’ 8.
Loudon’s ‘Gard. Mag.,’ vol. vii. 1831, 259, 518, 526 et seq.
p. 696. 53 ‘ Fortsetzung,’ 1763, 8.29; ‘ Dritte

49 « Gardener’s Chron.,’ 1846, p. 601. Fortsetzung,’ s. 44, 96; ‘Act. Acad.
50 ¢Philosoph. Transact. 1799, p. St. Potorsure,’ 1782, part ii., p. 2513

201. ‘Nova Acta,’ 1793, pp. 391, 394 ;
51 Quoted in ‘ Bull. Bot. Soc. France,’ ‘Nova Acta,’ 1795, pp. 316, 328.

|
|

Cuap. XVII. EVIL FROM INTERBREEDING. 131

Herbert; but the most striking exceptions are given by Max Wichura,'4
who found that hybrid willows were generally tender in constitution,
dwarf, and short-lived.

Kolreuter explains the vast increase in the size of the roots, stems, &c.,
of his hybrids, as the result of a sort of compensation due to their sterility,
in the same way as many emasculated animals are larger than the perfect
males. This view seems at first sight extremely probable, and has been
accepted by various authors;*> but Giirtner® has well remarked that
there is much difficulty in fully admitting it; for with many hybrids there
isno parallelism between the degree of their sterility and their increased size
and vigour. The 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 their extra-
ordinary luxuriance of growth, together with their enormous roots,*” have
been transmitted to their progeny. The increased size of the hybrids pro-
duced between the fowl and pheasant, and between distinct species of phea-
sants, has been already noticed. The result in all cases is probably in part
due to the saving of nutriment and vital force through the sexual organs
not acting, or acting imperfectiy, but more especially to the general law of
good being derived from across. For it deserves especial attention that
mongrel animals and plants, which are so far from being sterile that their
fertility is often actually augmented, have, as previously shown, their size,
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®* 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 justly
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 which, either normally or abnor-

mally, 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,

4 “Die Bastardbefruchtung,’ &e., 5¢ “ Bastarderzeugung,’ s. 394, 526,
1865, s. 31, 41, 42. 528.

55> Max Wichura fully accepts this 7 Kolreuter, ‘Nova Acta,’ 1795, p.
view (‘ Bastardbefruchtung,’ s. 43),as 316.
does the Rev. M. J. Berkeley, in ‘ Jour- °8 Gartner, ‘Bastarderzeugung,’ sg,
nal of Hort. Soc.,’ Jan. 1866, p. 70. 430,

kK 2

132 GOOD FROM CROSSING. Cap. XVI

close interbreeding. These facts are, however, connected with
our present subject, because a cross with a distinct individual
is shown to be either necessary or advantageous. Dimorphie
and trimorphic plants, though they are hermaphrodites, must
be reciprocally 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. Hildebrand :°—

Primula sinensis is a reciprocally dimorphic species: Dr. Hildebrand
fertilised twenty-eight flowers of both forms, each by pollen of the other
form, and obtained the full number of capsules containing on an average
42°7 seed per capsule; here we have complete and normal fertility. He
then fertilised forty-two flowers of both forms with pollen of the same
form, but taken from a distinct plant, and all produced capsules con-
taining on an average only 19°6 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.

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 some-
times 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 dif-
ferent family.

Sixty-three flowers of Corydalis cava, borne 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

°° “Botanische Zeitung,’ Jan. 1864, Berlin, 1866, s. 372.
8. 3. 61 International Hort. Congress,
°0 *Monatsbericht Akad. Wissen,’ London, 1866.

Cuap. XVII. SELF-IMPOTENT PLANTS. 133

4:5 seed in each. He then fertilised sixteen flowers produced 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 spontaneously 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
different 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. Oncidiwm sphacelatum 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 O. divari-
catum ; 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 ferti-
lised by the pollen of O. divaricatum produced four fine capsules: again,
between two and three hundred flowers of O. divaricatum, fertilised by
their own pollen, did not set a capsule, but twelve flowers fertilised by O.
flecuosum produced eight fine capsules: 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 Oncidium flecuosum, and probably 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 O. microchiiwm 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 O. 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
by M. Riviére,* with two plants of O. Cavendishianum, which were both self-
sterile, but reciprocally fertilised each other. All these cases refer to the
genus Oncidium, but Mr. Scott found that Mawillaria atro-rubens was
“totally insusceptible of fertilisation with its own pollen,” but fertilised,
and. was fertilised by, a widely distinct species, viz. M. squalens.

As these orchids had grown under unnatural conditions, in hot-

© ‘Proc. Bot. Soc. of Edinburgh,’ Bot., 1864, p. 162.

May, 1863 : these observations are given 63 Prof, Lecoq, ‘ De la Fécondation,’

in abstract, and others are added, in the 2nd edit., 1862, p. 76.
‘Journal of Proce. of Linn. Soc.,’ vol. viii,

134 GOOD FROM CROSSING. CHap, XVII,

houses, I concluded without hesitation that their self-sterility was due to
this cause. But Fritz Miller informs me that at Desterro, in Brazil, he
fertilised above one hundred flowers of the above-mentioned Oncidiyj,
flecuosum, which is there endemic, with its own pollen, and with that
taken from distinct plants; all the former were sterile, whilst those foy-
tilised 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-capsules when impregnated with pollen of widely
distinct genera, such as Leptotes, Cyrtopodium, and Rodriguezia! Onci-
dium 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
Lpidendrum cinnabarinum, an orchid belonging to another division of the
family, fine pods were produced by the plant’s own pollen, but they con-
tained by weight only about half as much seed 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 embryon-
less and worthless. Some self-fertilized capsules of a Maxillaria were ina
similar state.

Another observation made by Fritz Miiller igs 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 discoloura-
tion and decay are not caused by parasitic 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 of Oncidium flecuosum, 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 fleauosum,
and of the Hpidendrum zebra (nov. spec, ?), were placed together on the
same stigma, they behaved in exactly the same manner, the grains
separating, emitting tubes, and penetrating the stigma, so that the two

Cuap, XVII. SELF-IMPOTENT PLANTS. 135

pollen-masses, after an interval of eleven days, could not be distin-
guished 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 Oncidiwm flecuosum, O. unicorne, 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. Numerous 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
Oncidium flecuosum. 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 penetrated 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 orchids the pollen long remains undecayed ;
but Notylia behaved in this respect differently; for when its pollen was
placed onthe stigma of Oncidiwm flecuosum, both the stigma and pollen
quickly became 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 pollen is
not only impotent (thus effectually preventing self-fertilization), but like-
wise prevents, as was ascertained in the case of the Notylia and Oncidiwm
flecuosum, the action of subsequently applied pollen from a distinct
individual, it would be an advantage to the plant to have its own pollen
rendered more and more deleterious; 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.

Ty . . °
We now come to cases closely’analogous with those just

MC SKE ee ee ote

iy > ee ee.

a ny till th nied

136 GOOD FROM CROSSING. Cuap, XVII,

given, but different, inasmuch as individual plants alone of the
species 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 fertilised 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 con-
stituted 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 manner by
the conditions to which they themselves or their parents have
been exposed; but whilst thus rendered self-sterile, they have
retained the capacity common to most species of partially
fertilizing and being partially fertilized by allied forms. How-
ever this may be, the subject, to a certain extent, is related
to our general conclusion that good is derived from the act of
crossing.

Gartner experimented on two plants of Lobelia Julgens, brought from
separate places, and found" 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 fertilised 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 Gértner™
capable of fertilising V. lychnitis 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, gives the case of three

ss ane

64 ¢ Bastarderzeugung,’ s. 64, 357. % Idem, s. 357.
2s
66 * Zweite Fortsetzung,’ s. 10; ‘Dritte Fort.,’ s. 40.

Cuar. XVII. SELF-IMPOTENT PLANTS. 137

garden plants of Verbascwm pheeniceum, which bore during two years many
flowers; these he successfully fertilised by the pollen of 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 condition, being temporarily sterile
on the male or female side, or on both sides, and sometimes fertile on
both sides; but two of the plants were perfectly fertile throughout the
summer.

It appears” that certain flowers on certain plants of Liliwm candidum
can be fertilised more easily by pollen from a distinct individual than by
their own. So, again, with the varieties of the potato. Tinzmann,%* who
made many trials with this plant, says that pollen from another variety
sometimes “ exerts a powerful influence, 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
to act 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. Mowbray ® found that he could not get fruit from P. alata and
racemosa except by reciprocally fertilising them with each other’s pollen.
Similar facts have been observed in Germany and France ;” and I have
received two authentic accounts of P. quadrangularis, which never pro-
duced fruit with: its own pollen, but would do so freely when fertilised in
one case with the pollen of P. cerulea, and in another case with that of
P. edulis. So again, with respect to P. laurifolia, a cultivator of much
experience has recently remarked” that the flowers “must be fertilised
with the pollen of P. cerulea, 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:” plants of Passifora racemosa, cerulea, and
alata flowered profusely during many years in the Botanic Gardens of
Edinburgh, and, though ‘repeatedly fertilised by Mr. Scott and by others
with their own pollen, never produced 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. cerulea, three plants, two of which grew in the
Botanic Gardens, 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 distinct plant; thus sixteen flowers sponta-

8? Duvernoy, quoted by Gartner, 7 Prof. Lecog, ‘De la Fécondation,’
‘ Bastarderzeugung,’ s. 334. 1845, p. 70; Gartner, ‘ Bastarderzeug-
* * Gardener's Chronicle,’ 1846, p. ung,’ s, 64.
183. 71 «Gardener’s Chron.,’ 1866, p. 1068,
% «Transact. Hort. Soe.,’ vol. vii., 72 ¢ Journal of Proc. of Linn. Soe.,’
1830, p. 95. vol. viii, 1864, p. 1168.

138 GOOD FROM CROSSING. Cap, XVII,

neously self-fertilised produced fruit, each containing on an average 21:3
seed, whilst fruit from fourteen crossed flowers contained 24°1 seed.
Returning to P. alata, 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 which was formerly grafted by Mr.

Donaldson on a distinct species, name unknown, and ever since the

operation it has produced fruit in abundance by its own pollen; so that
this small and unnatural change in the state of this plant has restored 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. Pollen from the Taymouth
plant failed to fertilise certain plants of the same species, but was successful
on one plant in the 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 by her 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, eighteen 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 com-
pletely destroyed fertility of pure species when impregnated
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 Hip-
peastrums, 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 ‘ Horticultural 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.

3 * Amaryllidacew,’ 1837, p. 371; ‘Journal of Hort. Soc.,’ vol. ii., 1847, p. 19.

Cuap, XVII. SELF-IMPOTENT PLANTS. 139

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 //. bulbulosum, regine,
and vittatum; the result was, that “the ovaries of the three first flowers
“soon ceased to grow, and after a few days perished entirely : 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,’4
after much experience in crossing the species of Amaryllis (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,” asserts that Amaryllis belladonna
bears many more seeds when fertilised by the pollen of Brunswigia (Ama-
ryllis of some authors) Josephine 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 Vallota (Amaryllis) 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.”"® These latter cases, however, relate to uncrossed
species, like those before given with respect to Passiflora, Orchids, &c., and
are here referred to only because 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 hybrids; and a cross, whichever
way taken, always proved highly beneficial. I can add a striking and
analogous case from experiments made by the Rev. A. Rawson, of Bromley
Common, with some complex hybrids of Gladiolus. This skilful horti-
culturist possessed a number of French varieties, differing from each other
only in the colour and size of the flowers, all descended from Gandavensis,
a well-known old hybrid, said to be descended from G. Natalensis by the
pollen of G. oppositiflorus.” Mr. Rawson, after repeated trials, found
that none of the varieties would set seed with their own pollen, although

74 Loudon’s “Gardener’s Magazine,’
vol. xi., 1835, p. 260.

7 *Gardener’s Chronicle,’ 1850, p.
470.

76 “Journal Hort. Soce.,’ vol. y. p.
135. The seedlings thus raised were
given to the Hort. Soc. ; but I find, on
inquiry, that they unfortunately died
the following winter.

77 Mr. D. Beaton, in ‘Journal of
Hort.,’ 1861, p. 453. Lecoq, however
(‘De la Fécond., 1862, p. 369), states
that this hybrid is descended from
G. psittacinus and cardinalis; but this
is opposed to Herbert’s experience, who
found that the former species could not
be crossed.

ee ee a a

140 - GOOD FROM CROSSING. Cuar. XVII,

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 give two examples: Ophir did not produce a capsule
with its own pollen, but when fertilised with that of Janire, Brenchleyensis,
Vulcain, and Linné, it produced ten fine capsules ; but the pollen of Ophir
was good, for when Linné was fertilised by it seven capsules were
produced. This latter variety, on the other hand, was utterly barren 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 curious 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, dicecious; “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 elements 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 in this peculiar
state, we may conclude that it has been naturally acquired for
the sake of effectually preventing self-fertilisation. The case 18
closely analogous with dimorphic and trimorphic plants, which
ean be fully fertilised 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 completely
sterile with pollen taken from the same plant or from the same

Cuap, XVU. CONCLUSION. 141

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 cultivated in
pots, we may attribute it to some change in the conditions of
life, acting on the plants themselves or on their parents. The
selfimpotent Passiflora alata, which recovered its self-fertility
after having been grafted on a distinct stock, shows how small
a change is sufficient 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 probably congenital.

K6lreuter, 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 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 exposure 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-im potent
plants; for, as we shall see in the following chapter, certain
monkeys, the larger carnivora, several finches, geese, and phea-
sants, cross together, quite as freely as, or even more freely than,
the individuals of the same species breed together. Cases will,

and female domesticated animals, which, nevertheless, are fertile
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 vigour, 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 interbreeding), and is practically exemplified in
the higher value of cross-bred animals for immediate consump-
tion. 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 deteriorated 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 men-
tioned 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 between the nearest blood-relations. It applies to individuals
of the same sub-variety but of distinct families, to varieties or
races, to sub-species, as well as to quite distinct species.

|
In this latter case, however, whilst size, vigour, precocity,

142 GOOD FROM CROSSING. Cuap. XVII,

: also, be given of sexual incompatibility between certain male

;

:

and hardiness are, with rare exceptions, gained, fertility, in a
greater or less degree, is lost; but the gain cannot be exclu-
sively attributed to the principle of compensation; for there is
no close parallelism between the increased size and vigour of
the offspring and their sterility. Moreover it has been clearly
proved that mongrels which are perfectly fertile gain these
same advantages as well as sterile hybrids.

The evil consequences of long-continued close interbreeding
are not so easily recognised as the good effects from crossing,
for the deterioration is gradual. Nevertheless 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

Cuap, XVII. CONCLUSION. 143

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 gene-
rations. ‘here is good reason to believe that by keeping the
members of the same family in distinct bodies, especially if
exposed to somewhat different conditions of life, and by occa-
sionally crossing these families, the evil results may be much
diminished, or quite eliminated. These results are loss of con-
stitutional vigour, size, and fertility; but there is no necessary
deterioration in the general form of the body, or in other good
qualities. We have seen that with pigs: first-rate animals have
been produced after long-continued close interbreeding, 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 infertility of this peculiar
nature being one of the results of long-continued interbreeding,
shows that interbreeding does not act merely by combining
and augmenting various morbid tendencies common to both
parents; for animals with such tendencies, if not at the time
actually ill, can generally propagate their kind, Although
offspring descended from the nearest blood-relations are not
necessarily deteriorated in structure, yet some authors” 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

7% This is the conclusion of Prof. 354, some curious evidence on half the
Devay, ‘Du Danger des Mariages Con- cages of a peculiar form of blindness

sang.’ 1862, p. 97. Virchow quotes, occurring in the offspring from near
in the ‘Deutsche Jahrbiicher,’ 1863, 5, relations.

144 GOOD FROM CROSSING. Cuap, XVII,

that evil follows from close interbreeding, and when we bear in
mind that throughout the whole organic world elaborate pro-
vision has been made for the occasional union of distinct indj-

viduals, 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.

*

aed

Cuap, XVIII. GOOD OF CHANGED CONDITIONS. 145

CHAPTER x°Vrtt,

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

ON THE GOOD DERIVED FROM SLIGHT CHANGES IN THE CONDITIONS OF LIFE—

STERILITY FROM CHANGED CONDITIONS, IN ANIMALS, IN THEIR NATIVE COUNTRY
AND, IN MENAGERIES — MAMMALS, BIRDS, AND INSECTS — LOSS OF SECONDARY
SEXUAL CHARACTERS AND OF INSTINCTS— CAUSES OF STERILITY — STERILITY
OF DOMESTICATED ANIMALS FROM CHANGED CONDITIONS — SEXUAL INCOMPATI-
BILITY OF INDIVIDUAL ANIMALS — STERILITY OF PLANTS FROM CHANGED CONDI-
TIONS OF LIFE — CONTABESCENCE OF THE ANTHERS — MONSTROSITIES AS A CAUSE
OF STERILITY — DOUBLE FLOWERS — SEEDLESS FRUIT — STERILITY FROM THE
EXCESSIVE DEVELOPMENT OF THE ORGANS OF VEGETATION — FROM LONG-CONTINUED
PROPAGATION BY BUDS INCIPIENT STERILITY THE PRIMARY CAUSE OF DOUBLE
FLOWERS AND SEEDLESS FRUIT.

On the Good derived from slight Changes in the Conditions 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 probable that the good derived from slight
changes in the conditions of life, from being an analogous phe-
nomenon, 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 exposed to
slightly changed conditions. Now, every one must have ob-
served the remarkable influence on convalescents 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 evidence is strong that a ereat advantage is
derived from exchanging seeds, tubers, bulbs, and cuttings from

one soil or place to another as different as possible.

VOL. II. z ; T,

146

ON THE GOOD DERIVED Cuap. XVII,

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.’ A sagacious observer, Bradley, writing in 17942
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 Farmers
“have failed in their Crops and been great Losers.” He then gives his
own practical experience on this head. A modern writer* asserts, “ Nothing
“can be more clearly established in agriculture than that the continual
“ ovowth of any one variety in the same district makes it liable to dete-
“ rioration either in quality or quantity.” 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 favour of the crop
from the latter seed was remarkable. A gentleman in Surrey who hag
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.

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 the Vosges 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.*

A well-known practical gardener, Mr. Robson,> 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

1 For England, see below. For Walker’s ‘Prize Essay of Highlond

Also

Germany, see Metzger, ‘ Getreidearten,’
1841, 5.63. For France, Loiseleur-Des-
longchamps (‘ Consid. sur les Céreales,’
1843, p. 200) gives numerous references
on this subject. For Southern France,
see Godron, ‘ Florula Juvenalis,’ 1854,
p. 28.

2 «A General Treatise of Husbandry,’
vol. iii. p. 58.

3 « Gardener’s Chronicle and Agricult.
Gazette? 1858, p. 247; and for the
second statement, idem, 1850, p. 702.
On this same subject, see also Rev. D.

Agricult. Soc.,’ vol. ii. p. 200.
Marshall’s ‘Minutes of Agriculture,
November, 1775.

4 Oberlin’s ‘Memoirs,’ Eng. translat.
p. 73. For Lancashire, see Marshall's
‘Review of Reports,’ 1808, p. 299.

5 ‘Cottage Gardener, 18956, Pp. 186.
For Mr. Robson’s subsequent state-
ments, see ‘Journal of Horticulture,
Feb. 18, 1866, p. 121. For Mr. Abbey §
remarks on grafting, &c., idem, July 18,
1865, p. 44.

Cuap. XVII. FROM CHANGED CONDITIONS. 147

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 Cal-
ceolaria, 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 seeds of the variety which is to be grafted; and he
believes this cannot be altogether explained by the stocks in question being
better 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 vigorously than when
grafted on closely allied stocks, afterwards often become unhealthy.

I have studied M. Tessier’s careful and elaborate experiments,’ 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. Another excellent observer, Colonel Le
Couteur,’ 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 exchanging seed,
tubers, &c., seems to be fairly well founded. Considering the
small size of most seeds, it seems hardly credible that the ad-
vantage thus derived can be due to the seeds obtaining in one
soil some chemical element deficient in the other goil, Ag
plants after once germinating 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 continually wander about; and this apparently is the

® ‘Mem. de l’Acad. des Sciences,’ 1790, p. 209.
7 «On the Varieties of Wheat,’ p. 52.

G2

148 STERILITY FROM Cuap. XVITI

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 circumstances to
which each organism is exposed. All forces throughout nature,
as Mr. Herbert Spencer® remarks, tend towards an equili-
brium, and for the life of 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 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 interbreeding prolonged
during many generations, during which the germ will be acted
on by'a male having almost identically the same constitution.

Sterility from changed Conditions of Lnfe.

I will now attempt to show that animals and plants, when re-
moved 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 opposed 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 variability.
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 rela-
tion to each other.

It is notorious that many animals, though perfectly tamed,

8 Mr. Spencer has fully and ably dis- breeding, and of the evil effects from
cussed this whole subject in his‘Prin- great changes in the conditions and
ciples of Biology” 1864, vol. ii. ch. x. from crossing widely distinct forms, a8
In the first edition of my ‘Origin of a series of facts “connected together by
Species,’ 1859, p. 267, I spoke of the some common but unknown bond, which

good effects from slight changes in is essentially related to the principle
the conditions of life and from cross- life,”

Cua, XVIIL CHANGED CONDITIONS. 149

refuse to breed in captivity. Isidore Geoflroy St. Hilaire?
consequently has drawn a broad distinction between tamed
animals which will not breed under captivity, and truly domes-
ticated animals which breed freely—generally more freely,
as shown in the sixteenth chapter, than in a state of nature.
It is possible and generally easy to tame most animals; but
experience has 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 materials 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 1838-46, in which the animals 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 Zoological Gardens. I should
premise that a slight change in the treatment of animals some-
times makes a great difference 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 1846. It is, also, mani-
fest from FI’. Cuvier’s account of the Jardin des Plantes,'° that
the animals formerly bred much less freely there than with us;
for instance, in the Duck tribe, which is highly prolific, 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. Rengger,” who
in Paraguay particularly attended to this subject, specifies six quadrupeds
in this condition; and he mentions two or three others which most rarely

Spee Be Roney Nip ea.
Q 1 7 N 4. Ss. ve oe .
* ‘ Essais de Zoologie Générale,’ 1841, 1 *Saugethiere von Paraguay,’ 1830,

p. 256. 8. 49, 106, 118, 124, 201, 208, 249, 265,
* Du Rut, ‘Annales du Muséum, 327.
1807, tom. ix. p. 120,

150 STERILITY FROM Cuap. XVIII

breed. Mr. Bates, in his admirable work on the Amazong, strongly
insists on similar cases; and he remarks, that the fact of thoroughly
tamed native mammals and birds not breeding when kept by the Indiang
cannot be wholly accounted for by their negligence or indifference, fe
the turkey and fowl are kept and bred by various remote tribes, Ty
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® 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“ to breed in India
far more readily than the elephant. our 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 generally been crossed one with
another. Most of the members of the pig family breed readily in our
menageries: even the Red River hog (Potamocherus 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”™ 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 Annual Reports of
the Zoological Gardens, and in the Gleanings from Lord Derby’s menagerie.

The Carnivora, with the exception of the Plantigrade division, generally
breed (though with capricious exceptions) almost as freely as ruminants.
Many species of Felidz have bred in various menageries, although imported
from various climates and closely confined. Mr. Bartlett, the present
superintendent of the Zoological Gardens," remarks that the lion appeal’
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;

2<The Naturalist on the Amazons,’ 14 « Journal,’ vol. i. p. 213.
1863, vol. i. pp. 99, 193; vol. ii. p. 5 ¢Saugethiere,’ s, 327.
113. 16 On the Breeding of the larger

3 «Embassy to the Court of Ava, Felida, ‘ Proc. Zoolog. Soc.,, 1861, P:
vol. i, p. 534, 140.

Cuap. XVII. CHANGED CONDITIONS. 151

“but there are several well-authenticated instances of the female tiger
preeding 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 (/elis jubata) has never been known by Mr. Bartlett to breed
in England, but it has bred 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 them-
selves in a state of nature are serviceable and worth training.” According
to Rengger, two species of wild cats -in Paraguay, though thoroughly
tamed, have never bred. Although so many of the Felide 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
formerly less freely exposed to the air and cold than at present, and this
change of treatment, as I was assured by the former superintendent, Mr.
“Miller, greatly increased their fertility. Mr. Bartlett, and there cannot be
a more capable judge, says, “ it is remarkable that lions breed more freely
“in travelling collections than in the Zoological Gardens; probably the
“ constant excitement and irritation 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 untameable 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 occurrence with the European
fox: the silver fox of North America (Canis argentatus), however, has bred
several times in the Zoological 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
Paradoxurus absolutely refuse to breed in the Zoological Gardens. The
Genetta has bred both here and in the Jardin des Plantes, and produced
hybrids. The Lerpestes fasciatus 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 (Meles taxus)
has bred several times in the Gardens; but I have not heard of this

17 Sleeman’s ‘ Rambles in India,’ vol. ii. p. 10.

152 STERILITY FROM Citar: XVII.
occurring elsewhere in England, and the event must be very rare, for an
instance in Germany has been thought worth recording.8 Jn Paraguay
the native Nasua, though kept in pairs during many years and perfectly
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, oy
the Cercoleptes, breed in the region of the Amazons. Two other planti-
grade genera, Procyon and Gulo, though often kept tame in Paraguay, never
breed there. In the Zoological Gardens 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. abun-
dantly 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 affinity, that the one native
rodent of Paraguay, which there breeds /ree/y 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,
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, chin-
chilla, and the agouti (Dasyprocta aguti), several times. This 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. Nor does the paca (Celogenys
paca) breed there. The common hare when confined has, I believe, never
bred in Europe;* though, according to a recent statement, it has crossed
with the rabbit. I have never heard of the dormouse breeding in confine-
ment. But squirrels offer a more curious case: with one exception, no
Species has ever bred in the Zoological Gardens, yet as many as fourteen
individuals of S. palmarum were kept together during several years. The
S. 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." At Lord Derby’s menagerie squirrels
of many kinds were kept in numbers, but Mr. Thompson, the superin-
tendent, 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 con-
finement. 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 squirrel (Sciwropterus volucclla): it has, also, bred several times

18 Wiegmann’s ‘Archif fiir Natur- is now positively denied, yet Dr.
gesch.,’ 1837, s. 162. * Pigeaux (‘Annals and Mag. of Nat.

19 Rengger, ‘ Saugethiere, &c.,s.276. Hist.,’ vol. xx., 1867, p. 75) affirms that
On the parentage of the guinea-pic, the hare and rabbit have produced
see also Isid. Geoffroy St. Hilaire, ‘ Hist. hybrids. :
Nat. Gén.’ 1 «Quadrupeds of North America,

*» Although the existence of the by Audubon and Bachman, 1846, P.
Leporides, as described by Dr. Broca 268.
(‘Journal de Phys., tom. il. p. 370),

en ee See

Cuap. XVII. CHANGED CONDITIONS. 153
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.”

Monkeys, in the nine-year Report from the Zoological Gardens, are
stated to unite most freely, but during this period, though many indi-
viduals were kept, there were only seven births. I have heard of one
American monkey alone, the Ouistiti, breeding in Europe.” <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 hamadryas,* and a Cer-
cepithecus have bred in the Zoological Gardens, and the latter species

at. the Duke of Northumberland’s. Several members of the family of.
. Lemurs have produced hybrids in the Zoological Gardens. It is much

more remarkable that monkeys very rarely breed when confined in their
native country; thus the Cay (Cebus azar) is frequently and completely
tamed in Paraguay, but Rengger® 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 fre-
quently tamed by the aborigines in Brazil.2® In the region of the
Amazons, these animals are so often kept in a tame state, that Mr. Bates
in walking through the streets of Para counted thirteen species; but, as
he asserts, they have never been known to breed in captivity.”

Birds.

Birds offer in some respects better evidence than quadrupeds, from their
breeding more rapidly and being kept in greater numbers. We have seen
that carnivorous animals are more fertile under confinement than most
other mammals. The reverse holds good with carnivorous birds. It is
said’ that as many as eighteen species have been used in Europe for
hawking, and several others in Persia and India;* they have been kept in
their native country in the finest condition, and have been flown during
six, eight, or nine years; *® 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 Sweden, there can

2 Loudon’s ‘ Mag. of Nat. Hist.,’ vol.
ix., 1836, p. 571; Audubon and Bach-
man’s.‘ Quadrupeds of North America,’
p. 221.

*3 Flourens, ‘ De I’Instinct,’ &c., 1845,
p. 88.

4 See ‘ Annual Reports Zoolog. Soe.,’
1855, 1858, 1863, 1864 ; ‘ Times’ news-
paper, Aug. 10th, 1847; Flourens, ‘ De
V'Instinct, p. 85.

*5 ‘Saugethiere,’ &c., s, 34, 49,

26 Art. Brazil, ‘Penny Cyclop.,’ p-
363.

7 *The Naturalist on the River
Amazons,’ vol. i. p. 99.

28 «Encyclop. of Rural Sports,’ p.

* 691.

29 According to Sir A. Burnes
(‘Cabool,’ &c., p. 51), eight species
are used for hawking in Scinde.

30 Toudon’s ‘ Mag. of Nat. Hist.,’ vol.
vi., 1833, p. 110.

AFUE ape Nt naar AN Pe EG has CAI MIL RT ARTE SSE yO MCL: PT ESS

a, ee ne ee Ne ee ee ly Ve ee

TL Oe SO SOTO wed ete EE ey Tw me RRS es

154. STERILITY FROM CHap. XVI]

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." No hawk
vulture, or owl has ever produced fertile eggs in the Zoological Gardens
or in the eld Surrey Gardens, with the exception, in the former place de
one occasion, of a condor and a kite (Milvus niger). Yet several Species,
namely, the Aguila fusca, Halicetus leucocephalus, Falco tinnunculus, F. sub.
buteo, and Buteo vulgaris, have been seen to couple in the Zoological
Gardens. Mr. Morris” mentions as a unique fact that a kestrel (Fuleo
tinnunculus) bred in an aviary. The one kind of owl which has been
known to couple in the Zoological Gardens was the Eagle Owl (Bubo
maximus); and this 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,”
actually reared their young. Mr. Gurney has given another Instance of '
this same owl breeding in confinement; and he records the ease of a second
species of owl, the Strix passerina, breeding in captivity.

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** remarks, their propagation is “ uncommonly difficult.”
The canary-bird shows that there is no inherent difficulty in these birds
breeding freely in confinement; and Audubon says*® 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 remarkable 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 (Fringilla spinus), have reproduced their own
kind. Even the bullfinch (Lowia pyrrhula) has bred as frequently with
the canary, though belonging to a distinct genus, as with its own species.”
With respect to the skylark (Alauda arvensis), 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; nevertheless one case has been recorded. In the nine-
year Report from the Zoological Society, twenty-four incessorial species
are enumerated which had not bred, and of these only four were known
to have coupled.

Parrots are singularly long-lived birds; and Humboldt mentions the
curious fact of a parrot in South America, which spoke the language of

REED lest RO Se EO
*! F, Cuvier, ‘Annal, du Muséum,’ %° «Ornithological Biography,’ vol. v.
tom. ix. p. 128. p. 517,
® «The Zoologist,’ vol. Vii.-viii., 1849- 37 A case is recorded in ‘The Zoolo-
90, p. 2648, gist,’ vol. i.-ii., 1843-45, p. 453. For
8 Knox, ‘ Ornithological Rambles in the siskin breeding, vol. iii.-iv., 1845-46,
Sussex,’ p. 91. p. 1075. Bechstein, ‘Stubenvogel,’ 5.

34 «The Zoologist,’ vol. vii.-viii., 1849- 139, speaks of bullfinches making nests,
50, p. 2566; vol. ix.-x., 1851-2, p. but rarely producing young. aes
3207, 388 Yarrell’s ‘Hist. British Birds,

* Bechstein, ‘Naturgesch.der Stuben- 1839, vol. i. p, 412.
vogel, 1840, s, 20,

Cuap, XVII. CHANGED CONDITIONS. 155

an extinct Indian tribe, so that this bird preserved the sole relic of a lost
language. Even in this country there is reason to believe® 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 recording in the gravest publications. According to
Bechstein 4! the African Psittacus erithacus breeds oftener than any other
species: the P. macoa occasionally lays fertile eggs, but rarely succeeds in
hatching them; this bird, however, has the instinct of incubation some-
times so strongly developed, that it will hatch the eggs of fowls or pigeons.
In the Zoological Gardens and in the old Surrey 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 informed 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.”
In Jamaica, a resident naturalist, Mr. R. Hill, * says, “no birds more readily
“ submit to human dependence than the parrot-tribe, but no instance of a
“ narrot 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 (Gouwra coronata and
Victoric) produced hybrids; nevertheless, 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 perfectly well-adapted climate, but never once bred. The
Columba migratoria 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.™

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.*
With the Gallinaces, as with all other orders, there are marked and inex-

39 Loudon’s ‘Mag. of Nat. History,
vol. ix., 1836, p. 347.

40 «Mémoires du Muséum d'Hist.
Nat., tom. x. p. 314: five. cases of
parrots breeding in France are here
recorded, See also ‘ Report Brit. Assoc,
Zoolog.,’ 1843.

41 « Stubenvogel, s. 105, 83.

42 Dr. Hancock remarks (‘ Charles-
worth’s Mag. of Nat. Hist.,’ vol. ii., 1838,
p. 492), “it is singular that, amongst

the numerous useful birds that are indi-
genous to Guiana, none are found to
propagate among the Indians; yet the
common fowl is reared in abundance
throughout the country.”

43 ¢A Week at Port Royal, 1855,
p. 7.
44 Audubon, ‘ American Ornithology,’
vol. v. pp. 552, 557.

45 Moubray on Poultry, 7th edit., p.
133.

ey ee ee a Ee ea ee

156 STERILITY FROM ' Cnap. XVIII,

plicable exceptions in regard to the fertility of certain species and genera
under confinement. Although 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 eges.46 The American tribe of
Guans or Cracide are tamed with remarkable ease, but are very shy
breeders in this country; but with care various species were formerly
made to breed rather freely in Holland.* Birds of this tribe are often
kept in a perfectly tamed condition in their native country by the Indians,
but they never breed. It might have been expected that grouse from
their habits of life would not have bred in captivity, more especially ag
they are said soon to languish and die. But many cases are recorded of
their breeding: the capercailzie (Tetrao wregallus) has bred in the Zoolo-
gical Gardens; it breeds without much difficulty when confined in Norway,
and in Russia five successive generations have been reared: Tetrag tetria
has likewise bred in Norway; 7. Scoticus in Ireland; 7’. wmbellus at Lord
Derby’s; and 2. 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 (Cusuarius Bennettii) from New Ireland, has frequently
produced young in the various European menageries. The African
ostrich, though perfectly healthy and living 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. 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. 8S. Dixon informs me, 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: Grus montigresia has bred several times
in Paris and in the Zoological Gardens, as has G. cinerea at the latter
place, and G. antigone at Calcutta. Of other members of this great order,
Letrapteryx paradisea has bred at Knowsley, a Porphyrio in Sicily, and the
Gallinula chloropus in the Zoological Gardens. On the other hand, several

46 Temminck, ‘Hist. Nat. Gén. des 49 Bates, ‘The Naturalist on the
Pigeons,’ &c., 1813, tom. iii. pp. 288, Amazons,’ vol. i. p. 193; vol. ii. p, 112.
882; ‘ Annals and Mag. of Nat. Hist.,’ 50 Temminck, ‘ Hist. Nat. Gén.,’ &c.,

vol. xii., 1843, p. 453. Other species of — tom. iii. p. 125. For Tetrao urogallus, see
partridge have occasionally bred; as L, Lloyd, ‘Field Sports of North of
the red-legged (P. rubra), when kept Europe,’ vol. i. pp. 287, 314; and ‘ Bull.
in a large court in France (see‘ Journal de la Soe. d’Acclimat.,’ tom. vii., 1860,

de Physique,’ tom. xxv. p. 294), and in p. 600. For TT. Scoticus, Thompson,

the Zoological Gardens in 1856. ‘Nat. Hist. of Ireland,’ vol. ii., 1850, Pp.
47 Rev. E. 8. Dixon, ‘The Dovecote, 49. For 7. cupido, ‘ Boston J ournal of
1851, pp. 243-252, Nat. Hist.” vol. iii. p. 199. ‘
48 Temminck, ‘Hist. Nat. Gén. des 51 Marcel de Serres, ‘ Annales des Sci.

Pigeons,’ &e., tom. ii. pp. 456, 458; tom, Nat.,’ 2nd series, Zoolog., tom. xiii. P.
iii, pp. 2, 13, 47, 175.

Cuap. XVIII. CHANGED CONDITIONS. 157

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.” *?

No birds breed with such complete facility under confinement as the
members of the great Duck family; yet, considering their aquatic 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-Longchamps has recorded
the production of hybrids from forty-four different members of the family ;
and to these Professor Newton has added a few more cases. “ There is
not,” says Mr. Dixon,*4 “ in the wide world, a goose which is not in the strict
sense of the word domesticable;” that is, capable of breeding under con-
finement; but this statement is probably too bold. The capacity to breed
sometimes varies in individuals of the same species; thus Audubon ® kept for
more than eight years some wild geese (Anser Canadensis), but they would
not mate; whilst other individuals of the same species produced young
during the second year. I know of but one instance in the whole family
of a species which absolutely refuses to breed in captivity, namely, the
Dendrocygna viduata, although, according to Sir R. Schomburgk,* 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 the Zoological Gardens and
at Knowsley.

There is reason to believe that insects are affected by confinement like
the higher animals. It is well known that the Sphingide rarely breed
when thus treated. An entomologist *” in Paris kept twenty-five specimens
of Saturnia pyri, but did not succeed in getting a single fertile egg. A
number of females of Orthosia munda and of Mumestra suasa reared in
confinement were unattractive to the males.55 Mr. N ewport 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.*?
Mr. Atkinson could never succeed in India in making the Tarroo silk-moth
breed in confinement. It appears that a number of moths, especially
the Sphingide, when hatched in the autumn out of their proper season,

52 Dr. Hancock, in ‘ Charlesworth’s
Mag. of Nat. Hist., vol. ii., 1838, p. 491 ;
R. Hill, ‘A Week at Port Royal,’ p. 8;
‘Guide to the Zoological Gardens,’ by
P. L. Sclater, 1859, pp. 11, 12; ‘The
Knowsley Menagerie,” by Dr. Gray,
1846, pl. xiv.; E. Blyth, ‘ Report Asiatic
Soc. of Bengal,’ May, 1855.

°3 Prof. Newton, in ‘Proc. Zoolog.
Soe.,’ 1860, p. 336.

*! «The Dovecote and Aviary, p,
428,

> ‘Ornithological Biography,’ vol.
lil. p. 9.

** ‘Geograph. Journal,’ vol. xiii., 1844,
p. 32.

57 Loudon’s ‘ Mag. of Nat. Hist.,’ vol.
v., 1832, p. 153.

°8 ‘Zoologist,’ vols. v.-vi., 1847-48, p.
1660.

59 ¢ Transact. Entomolog. Soe.,’ vol.
iv., 1845, p. 60.

°° «Transact. Linn. Soc.,’ vol. vii. p.
40,

158 STERILITY FROM Cuap. XVII]

are completely barren; but this latter case is still involved ip some
obscurity.”

Independently of the fact of many animals under confine.
ment 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 (Linota cannabina) when caged does
not acquire the fine crimson colour on its breast, and one of the
buntings (Emberiza passerina) loses the black on its head, A
Pyrrhula and an Oriolus have been observed to assume the
quiet plumage of the hen-bird; and the Falco albidus returned
to the dress of an earlier saa Mr. Thompson, the superin-
tendent 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.

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
Rengger, with native animals confined in Paraguay. The
mother’s mill often fails. We may also attribute to the dis-
turbance 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 naturally 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 cap-

61 See an interesting paper by Mr. 506; Bechstein, ‘ Stubenvogel,’ s. 185
Newman, in the ‘Zoologist,’ 1857, p. ‘ Philosoph. Transact., 1772, p. 271.
5764; and Dr. Wallace, in ‘Proc. Bronn (‘Geschichte der Natur, * Band ii.
Entomolog. Soe.,’ June 4th, 1860, p. s. 96) has collected a number of cases
119. For the case of the deer, see ‘Penny

° Yarrell’s ‘ British Birds,’ vol. i. p. | Cyclop.,’ vol. viii. p. 350.

Cuap, XVIII. CHANGED CONDITIONS. 159

tivity, such as parrots, and hawks when used for hawking,
chetahs when used for hunting, and elephants. The reproduc-
tive organs 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 exclusively to a failure in their sexual
instincts: this may occasionally come into play, but there is
no obvious reason why this instinct should be especially liable
to be affected with perfectly tamed animals, except indeed in-
directly 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 ahd 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 removed from their natural conditions are
affected in nearly the same manner as animals, Change of
climate cannot be the cause of the loss of fertility, for, whilst
many animals imported into Europe from extremely different
climates breed freely, many others when confined in their
native land are completely sterile. Change of food cannot 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 carnivorous 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 -
animals; and there is no reason to suppose that much more
food would be given to them, than to our choice domestic
productions which retain their full fertility. Lastly, we may
infer from the case of the elephant, chetah, various hawks, and
of many animals which 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, what-
ever these habits may be, if great enough, tends to affect in
an inexplicable manner the powers of reproduction. The result

160 STERILITY FROM

Cuap, XVIII,

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 exceptions 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 import:
ation. When an animal which is generally sterile under con-
finement 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™ that many animals in the
Jardin des Plantes, after having produced young for three or
four successive generations, become sterile ; but this may be the
result of too close interbreeding. It is a remarkable circum-
stance that many mammals and birds have produced hybrids
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 refuse 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
injuriously on the reproductive system. The whole case is
quite peculiar, for these organs, though not diseased, are thus
rendered incapable of performing their proper functions, or per-
form them imperfectly.

Sterility of Domesticated Animals from changed conditions.— With respect
to domesticated animals, as their domestication mainly depends 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 the wild
species breed most readily in our menageries, have afforded us the greatest
number of domesticated productions. Savages in most parts of the world
are fond of taming animals;® and if any of these regularly produced

63 ¢ Journal de Physiologie,’ tom. ii. 65 Numerous instances could be given.
p. 347, Thus Livingstone (‘Travels, P- 217)
64 For additional evidence on this states that the King of the Barotse,
subject, see F. Cuvier, in ‘Annales du an inland tribe which never had any
Muséum,’ tom. xii. p. 119. communication with white men, -

OS ee a ee ae

Cuap, XVIII. CHANGED CONDITIONS. 161
young, and were at the same time useful, they would be at once domesti-
cated. If, when their masters migrated into other countries, they were in
addition 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 domes-
ticated animals, such as the reindeer and camel, offer an exception to this
rule. Many of our domesticated animals can bear with undiminished
fertility the most unnatural conditions; for instance, rabbits, guinea-pigs,
and ferrets breed in miserably confined hutches. Few European dogs
of any kind withstand without degeneration the climate of India; but
as long as they survive, they retain, as I hear from Dr. Falconer, their
fertility ; so it is, according 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. 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 abori-
ginal 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 occa-
sionally show signs of lessened fertility. Roulin asserts that in the hot
valleys of the equatorial Cordillera sheep are not fully fecund;™ and
according to Lord Somerville, the merino-sheep which he imported from
Spain were not at first perfectly fertile. It is said 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 before the canary-bird was fully fertile, and even
now first-rate breeding birds are not common.” In the hot and dry pro-
vince 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

extremely fond of taming animals, and
every young antelope was brought to
him. Mr. Galton informs me that the
Damaras are likewise fond of keeping
pets. The Indians of South America
follow the same habit. Capt. Wilkes
states that the Polynesians of the
Samoan Islands tamed pigeons: and
the New Zealanders, as Mr. Mantell
informs me, kept various kinds of
birds,

°° For analogous cases with the fowl,

Fah 0) aah

see Réaumur, ‘Art de faire Eclorre,’ &c.,
1749, p. 243; and Col. Sykes, in ‘Proce.
Zoolog. Soe.,’ 1832, &e. With respect
to the fowl not breeding in northern
regions, see Latham’s ‘ Hist. of Birds,’
vol. viii., 1823, p. 169.

°7 *Mém. par divers Savans, Acad.
des Sciences,’ tom. vi., 1835, p. 347.

68 Youatt on Sheep, p. 181.

69 J. Mills, ‘ Treatise on Cattle,’ 1776,
p. 72.

7 Bechstein, ‘ Stubenvogel,’ s, 242.

M

162 STERILITY FROM

Cuap, XVIII,

fertile as our geese in Europe. In the Philippine Archipelago the Z008e
it is asserted, will not breed or even lay eggs.” A more curious cage ig
that of the fowl, which, according to Roulin, when first introduced would not
breed at Cusco in Bolivia, but subsequently became quite fertile; and the
English Game fowl, lately introduced, had not as yet arrived at its full
fertility, for to raise two or three chickens from a nest of eggs was thought
fortunate. 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.” So we see that unnatural and
changed conditions of life produce some effect on the 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 fertile 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 related to our present subject. The cause
apparently lies in an innate sexual incompatibility of the pair which are
matched. Several instances 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 Chelsfield, in relation to horses, cattle, pigs, foxhounds, other dogs, and
pigeons.” 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 occurred 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 record-

ing, as they show, like so many previous facts, on what slight constitu-
tional differences the fertility of an animal often depends.

71 Crawfurd’s ‘ Descriptive Dict. of ix., 1862, pp. 380, 384. iu
the Indian Islands,’ 1856, p. 145. 73 For pigeons, see Dr. Chapuis, Le
7 «Bull. de la Soe. Acclimat.,” tom. Pigeon Voyageur Belge, 1865, p- 66.

CuAp, XVIII. CHANGED CONDITIONS. 163

Sterility of Plants from changed Conditions of Infe, and from

other causes.

In the vegetable kingdom cases of sterility frequently occur,
analogous with those previously given in the animal kingdom.
But the subject is obscured by several circumstances, presently
to be discussed, namely, the contabescence of the anthers, as
Girtner has named a certain affection—monstrosities—double-
ness 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 produce 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 re-
productive 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. Linnsous long ago
observed 4 that Alpine plants, although naturally loaded with seed, pro-
duce either few or none when cultivated in gardens. But exceptions
often occur: the Draba sylvestris, one of our most thoroughly 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
plants, found that various kinds, when cultivated, Spontaneously sowed
themselves.” Many plants which 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 have myself
observed. The tendency to sterility from this cause runs in families ;
thus, according to Girtner,’® it is hardly possible to give too much manure
to most Gramines, Cruciferee, and Leguminose, whilst succulent and
bulbous-rooted plants are easily affected. Extreme poverty of soil is less

74 ‘Swedish Acts,’ vol. i, 1739, p. 3.
Pallas makes the same remark in his

D, Cameron, also, has written on the
culture of Alpine plants in ‘Gard,

Travels (Eng. translat.), vol. i. p. 292.
> A. Kerner, ‘ Die Cultur der Alp-
enpflanzen,’ 1864, s. 139; Watson’s

‘Cybele Britannica,’ vol. i. p- 181; Mr.

Chronicle,’ 1848, pp. 253, 268, and
mentions a few which seed,

7‘ Beitrage zur Kenntnisg der
Befruchtung,’ 1844, s. 333.

M 2

164 STERILITY FROM CHANGED CONDITIONS. Cuav. xvqq]

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 temperature of the soil, and the season at which plants
are watered, often have a marked effect on their fertility, as was observed
by Kélreuter in the case of Mirabilis.” Mr. Scott in the Botanic Gardens
of Edinburgh observed that Oncidiwm divaricatum would not set geed
when grown in a basket in which it throve, but was capable of fertili-
sation in a pot where it was a little damper. Pelargonium fulgidum, for
many years after its introduction, seeded freely; it then became sterile;
now it is fertile’* if kept in a dry stove during the winter. Other varie-
ties of pelargonium are sterile and others 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 dif-
ference in its producing seed. ‘Temperature apparently has a much more
powerful influence on the fertility of plants than on that of animals,
Nevertheless it is wonderful what changes some few plants will withstand
with undiminished fertility: thus the Zephyrunthes 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.” Berberis Wallichit, from the hot Khasia range in India, is un-
injured by our sharpest frosts, and ripens its fruit under our cool summers,
Nevertheless I presume we must attribute to change of climate the
sterility of many foreign plants; thus the Persian and Chinese lilacs
(Syringa Persica and Chinensis), though perfectly hardy, never here pro-
duce a seed; the common lilac (S. vulgaris) seeds with us moderately well,
but in parts of Germany the capsules never contain seed.

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 or with
endemic plants cultivated in pots, and as it disappeared in the Passi/lora
alata when grafted, we may conclude 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.*' The female organs are more sensitive, for Gartner™ found that
dicotyledonous plants, when carefully removed so that they did not im
the least flag, could seldom be fertilised; this occurred even with potted

77 “Nova Acta Petrop.,’ 1798, p. 391. &c., s. 560, 564.
78 ‘Cottage Gardener,’ 1856, pp. 44, 81 «Gardener's Chronicle,’ 1844, P.

109. 215; 1850, p. 470. Wee
79 Dr. Herbert, ‘ Amaryllidacez,’ p. & ‘Beitrige zur Kenntniss, SC 8
176. 252, 333.

89 Gartner, ‘ Beitrage zur Kenntniss,’

Caap. XVIII. CONTABESCENCE. 165

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 fertilisa-
tion; 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 niutilated 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 Linum, 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.

Contabescence.—Gartner has designated by this term a peculiar condition
of the anthers in certain plants, in which they are shrivelled, or become
brown and tough, and contain no good pollen. When in this state they
exactly resemble the anthers of the most sterile hybrids. Giirtner,“t in his
discussion on this subject, has shown that plants of many orders are occa-
sionally thus affected; but the Caryophyllacese and Liliaces suffer most,
and to these orders, I think, the Ericaceze may be added. Contabescence
varies in degree, 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 (with 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 contabescent plants the female organs
are seldom affected, or merely become precocious in their development.
The cause of this affection is doubtful, and is different in different cases.
Until I read Giirtner’s discussion I attributed it, as apparently did Herbert,
to the unnatural treatment of the plants; but its permanence under
changed conditions, and the female organs not being affected, seem incom-
patible with this view. The fact of several endemic plants becoming
contabescent in our gardens seems, at first sight, equally incompatible
with this view; but Kolreuter believes that this is the result of their trans-
plantation. The contabescent plants of Dianthus and Verbascum, found
wild by Wiegmann, grew on a dry and sterile bank, The fact that exotic

= Agaxnek! ob ee ee eee ung,’ s. 10, 121; ‘Dritte Fortsetzung,’ s.

ai doa ie ae o7. Herbert, ‘ Amaryllidacee,’ p. 355.
Dele Renainiag &e., 8. Wiegmann, ‘Ueber die Bastarderzeu-
117 et seq.; Kolreuter, ‘ Zweite Fortsetz- gung,’ s. 27.

166 STERILITY.

Cuap. XVIII,

plants are eminently liable to this affection also seems to show that it ig
in some manner caused by their unnatural treatment. In some instances
as with Silene, Gartner’s view seems the most probable, namely, that it i
caused by an inherent tendency in the species to become dicecious. J can
add another cause, namely, the illegitimate unions of reciprocally dimorphic
or trimorphic plants, for I have observed seedlings of three species of
Primula and of Lythrum 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 additional 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 the
female organs struck with sterility, whilst the male organs remain perfect,
Dianthus Japonicus, a Passiflora, and Nicotiana, have been described by
Gartner ® as being in this unusual condition.

Monstrosities as a cause of Sterility.—Great deviations of structure, even
when the reproductive organs themselves are not seriously affected, some-
times 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,” 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 curious
St. Valery apple, although it bears fruit, rarely produces seed. The
wonderfully @nomalous flowers of Begonia frigida, formerly described,
though they appear fit for fructification, are sterile.’ Species of Pri-
mule, in which the calyx is brightly coloured, are said® 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 propa-
gated by seed. This was the case with a poppy, which had become
monopetalous by the union of its petals.*® Another extraordinary poppy,
with the stamens replaced by numerous small supplementary capsules,
likewise reproduces itself by seed. This has also occurred with a plant of
Saxifraga gewm, in which a series of adventitious carpels, bearing ovules
on their margins, had been developed between the stamens and the normal
carpels.° Lastly, with respect to peloric flowers, which depart wonder-
fully from the natural structure,—those of Linaria vulguwris seem generally
to be more or less sterile, whilst those before described of Antirrhinum
majus, when artificially fertilised with their own pollen, are perfectly

85 ‘ Bastarderzeugung,’ s. 356. in the ‘Phytologist, vol. ii. p. 489.
86 ‘Teoria della Riproduzione, 1816, Prof. Harvey, on the authority of Mr.
p. 84; ‘Traité du Citrus, 1811, p. 67. Andrews, who discovered the plant,

87 Mr. C. W. Crocker, in ‘Gard. informed me that this monstrosity could

Chronicle,’ 1861, p. 1092. be propagated by seed. With respect 0
88 Verlot, ‘ Des Variétiés, 1865, p. 80. the poppy, see Prof. Goeppert, as quoted
*° Verlot, idem, p, 88. in ‘Journal of Horticulture,’ July Ist,

% Prof. Allman, Brit. Assoc., quoted 1863, p. 171.

-

Cyap. XVIII. DOUBLE FLOWERS, 167

fertile, though sterile when left to themselves, for bees are unable to crawl
into the narrow tubular flower. The peloric flowers of Corydalis solida,
according to Godron,” 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 vain during several years to get seed from these flowers.
I likewise made many vain attempts, butsometimes succeeded in fertilising
them with pollen from a normal flower of another variety; and conversely
I several times fertilised ordinary flowers with peloric pollen. Only once
I succeeded in raising a plant from a peloric flower fertilised by pollen
from a peloric flower borne by another variety; but the plant, it may be
added, presented nothing particular in its structure. Hence we may con-
clude that no general rule can be laid down; but any great deviation from
the normal structure, even when the reproductive organs themselves are
not seriously affected, certainly often leads to sexual impotence.

Double Flowers.—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 develop-
ment of the corolla of their central florets. Doubleness is sometimes
connected with prolification,” or the continued growth of the axis of the
flower. Doubleness is strongly inherited. No one has produced, as
Lindley remarks,” double flowers by promoting the perfect health of the
plant. On the contrary, unnatural conditions of life favour their produc-
tion. There is some reason to believe that seeds kept during many years,
and seeds believed to be imperfectly fertilised, yield double flowers more
freely than fresh and perfectly fertilised seed.** Long-continued cultiva-
tion 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 observed to become single; 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 Professor
Morren that doubleness of the flowers and variegation of the leaves are
antagonistic states; but so many exceptions to the rule have lately been
recorded, that, though general, it cannot be looked at as invariable.

9 *Comptes Rendus,’ Dee, 19th, the removal of the anthers, see Mr.
1864, p. 1039. Leitner, in Silliman’s‘ North American
% *Gardener’s Chronicle,’ 1866, p. Journ. of Science,’ vol. xxiii. p.47; and
681. Verlot, ‘Des Variétés,’ 1865, p. 84.
% “Theory of Horticulture,’ p. 333. % Lindley’s ‘Theory of Horticulture,’
% Mr. Fairweather, in ‘Transact. p. 333.
Hort. Soc.,’ vol. iii, p. 406; Bosse, % «Gardener’s Chronicle,’ 1865, p.
quoted by Bronn, ‘ Geschichte der 626; 1866, pp. 290, 730; and Verlot,
Natur,’ B. ii. s. 77. On the effects of «Deg Varictés, p. 75.

168 _ STERILITY FROM THE Cuap. XVIII,

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 doubleness, which is the antagonistic state, com-
monly arises from a plethoric condition. On the other hand, extremely
poor soil sometimes, though rarely, appears to cause doubleness: |
formerly described” some completely double, bud-like, flowers produced
in large numbers by stunted wild plants of Gentiana amarella growing on
a poor chalky bank. I have also noticed a distinct tendency to doublenesg
in the flowers of a Ranunculus, Horse-chesnut, and Bladder-nut (Ranun-
culus repens, Aisculus pavia, and Staphylea), growing under very unfavour-
able conditions. Professor Lehman” 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 attempt to show that the most probable view is that
unnatural conditions 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 produced double
flowers.

Seedless Fruit—Many of our most valuable fruits, although consisting
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. Most horticulturists look at the great size and anomalous deve-
lopment of the fruit as the cause, and sterility as the result; but 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, &e.,. 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, i is necessary to check their
growth; and, when one-third grown, they are taken up, and their stems and

’

*7 “Gardener's Chronicle,’ 1843, p. 1816,p.101-110. Meyen(‘ Reise um Erde,
628. In this article I suggested the Th. ii. s. 214) states that at Manilla one
following theory on the doubleness of variety of the banana is full of seeds;

flowers. and Chamisso (Hooker's ‘Bot. Misc.,
98 Quoted by Gartner, ‘Bastarder- vol. i. p. 310) describes a variety of the
zeugung,’ s. 567, bread-fruit in the Mariana Islands with
% “Gardener's Chronicle,’ 1866, p. small fruit, containing seeds which are
901. frequently perfect. Burnes, in his

100 Lindley, ‘Theory of Horticulture,” ‘Travels in Bokhara,’ remarks on the
p. 175-179 ; Godron, ‘ Del Espéce,' tom. pomegranate seeding in Mazenderan, @5
li. p. 106; Pickering, ‘Races of Man;’ a remarkable peculiarity.

Gallesio, ‘Teoria della Riproduzione,’

Cuar. XVIII. DEVELOPMENT OF THE ORGANS OF VEGETATION. 169
tap-roots are cut or mutilated” So it is with hybrids; for instance, Prof.
Lecoq! had three plants of Mirabilis, which, though they grew luxu-
riantly 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 supply of suc-
culent stems, never, according to various observers, bears seed in the
West Indies, Malaga, India, Cochin China, or the Malay Archipelago.’
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 (Convolvulus batatas) in China never, as
far as he has seen, yields seed. Dr. Royle remarks™ that in India the
Agave vivipara, when grown in rich soil, invariably produces bulbs, but
no seeds; whilst a poor soil and dry climate leads to an opposite result.
In China, according to Mr. Fortune, an extraordinary number of little
bulbs are developed 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 organised 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., inde-
pendently 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 of sexual generation.
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 subject, I will here give
such cases as I have collected. Many alpine plants ascend mountains
beyond the height at which they can produce seed. Certain species of

1 Ingledew, in ‘Transact. of Agri- of Hort. Soc.,’ vol. i., 1846, p. 254—Dr.

cult. and Hort. Soe. of India,’ vol. ii.

102 “De la Fécondation,’ 1862, p. 308.

103 Hooker’s ‘Bot. Mise.,’ vol. i. p.
99; Gallesio, ‘Teoria della Ripro-
duzione,’ p. 110,

104 * Transact. Linn. Soe.,’ vol. xvii.
p. 963.

% Godron, ‘De l’Espéce,’ tom. ii. p.
106; Herbert on Crocus, in ‘Journal

Wight, from what he has seen in India,
believes in this view; ‘Madras Journal
of Lit. and Science,’ vol. iv., 1836, p.
61.

106 Wahlenberg specifies eight species
in this state on the Lapland Alps: see
Appendix to Linneus’ ‘Tour in Lap-
land,’ translated by Sir J. Ki. Smith,
vol, ii. pp. 274-280.

170 STERILITY,

Cuap. XVII,

Poa and Festuca, when growing on mountain-pastures, propagate them.
selves, as I hear from Mr. Bentham, almost exclusively by bulblets, Kalm
gives a more curious instance of several American trees, which LTOW so
plentifully in marshes or in thick woods, that they are certainly wel]
adapted for these stations, yet scarcely ever produce seeds; but when
accidentally 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 botanists.% 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 Lysimachia nummularia, which is furnished with long
runners, So seldom produces seed-capsules, that Prof. Decaisne, 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,
Germany, and New Hampshire in the United States.™ The periwinkle
(Vinca minor), which spreads largely by runners, is said scarcely ever to
produce fruit in England;™ 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 navigation of the waters,
but never produces fertile seed"? The horse-radish (Cochlearia armoracia)
Spreads pertinaciously and is naturalised 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 searcely a grain of good
pollen. The common little Ranunculus ficaria rarely, and some say never,
bears seed 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 bulbiferous form
which does not yield seed from producing no pollen Other cases analo-

17 © Travels in North America,’ Eng. 2G. Planchon, ‘Flora de Mont-
translat., vol. iii. p. 175. pellier,’ 1864, p. 20.
108 ‘With respect to the ivy and 13 On the non-production of seeds in

Acorus, see Dr. Bromfield in the ‘ Phy- England, see Mr. Crocker, in ‘Gar-
tologist, vol. iii. p. 876. See also dener’s Weekly Magazine,’ 1852, p. 70;
Lindley and Vaucher on the Acorus. Vaucher, ‘Hist. Phys. Plantes d Eu-
109 ¢ Annal. des Sc. Nat.,’ 3rd series, rope,’ tom. i. p. 33; Lecoq, ‘ Géograph.
Zool., tom. iv. p. 280. Prof. Decaisne Bot. de Europe,’ tom. iv. p. 466 ; Dr.
refers also to analogous cases with D. Clos, in ‘ Annal. des Se. Nat., 3rd
mosses and lichens near Paris. series, Bot., tom. xvii., 1852, p. 129: this
0 Mr. Tuckermann, in Silliman’s latter author refers to other analogous
‘ American Journal of Science,’ vol.xlv. cases. On the non-production of pollen
2; by this Ranunculus see Chatin, in
11 Sir J. E, Smith, ‘English Flora,’ + Comptes Rendus,’ June 11th, 1866.
vol, i. p. 339.

Cuap, XVII. STERILITY. 171

gous with the foregoing could be given; for instance, some kinds of mosses
and lichens have never been seen to fructify in France.

Some of these endemic and naturalised plants are probably rendered
sterile from excessive multiplication by .buds, and their consequent inca-
pacity 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 accompanies
the doubling of flowers,—the excessive development of fruit,
—and a great increase in the organs of vegetation, we must
bear in mind that the whole effect has seldom been caused at
once. An incipient tendency is observed, and continued selec-
tion completes the work, as 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 unnatural 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 functions, 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 far from wishing to deny that there
exists, independently of any incipient sterility, an antagonism
between 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 dif-
ferent cause, namely, from hybridism, there is a strong ten-
dency, as Girtner'* affirms, for flowers to become double, and
this tendency is inherited. Moreover it is notorious that with
hybrids the male organs become sterile before the female
organs, and with double flowers the stamens first become foli-

14 ‘ Bastarderzeugung,’ s. 565. K6l- one single and the other double, are
reuter (‘ Dritte Fortsetzung,’ s, 73, 87, crossed, the hybrids are apt to be
119) also shows that when two species, extremely double.

172 STERILITY.

CuAP. XVIII,

aceous. This latter fact is well shown by the male flowers of
dicecious plants, which, according to Gallesio,™ first become
double. Again, Gartner’ often insists that the flowers of even
utterly sterile hybrids, which do not produce any seed, generally
yield perfect capsules or fruit,—a fact which has likewise been
repeatedly observed by Naudin with the Cucurbitacez ; so that
the production of fruit by plants rendered sterile through any
other and distinct cause is intelligible. Kélreuter has algo eX-
pressed his unbounded astonishment at the size and development
of the tubers in certain hybrids; and all experimentalists"" haye
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, perfectly developed, even when containing no sced;
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 almost all organic beings
when exposed to unnatural conditions tend to become more or
less sterile, it seems much the most probable view that with
cultivated plants sterility is the exciting cause, and double
flowers, rich seedless 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.

"> “Teoria della Riproduzione Veg.,’ 1816, p. 73.
n° * Bastarderzeugung,’ s. 573. N7 Tbid., s. 527.

Cuap. XIX. SUMMARY OF THE FOUR LAST CHAPTERS. 173

CHATTER RAI x.

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

ON THE EFFECTS OF CROSSING — THE INFLUENCE OF DOMESTICATION ON FERTILITY
— CLOSE INTERBREEDING 300D AND EVIL RESULTS FROM CHANGED CONDITIONS
OF LIFE — VARIETIES WHEN CROSSED NOT INVARIABLY FERTILE —ON THE DIF-
FERENCE IN FERTILITY BETWEEN CROSSED SPECIES AND VARIETIES — CONCLUSIONS
WITH RESPECT TO HYBRIDISM — LIGHT THROWN ON HYBRIDISM BY THE ILLEGITI-
MATE PROGENY OF DIMORPHIC AND TRIMORPHIC PLANTS — STERILITY OF CROSSED
SPECIES DUE TO DIFFERENCES CONFINED TO THE REPRODUCTIVE SYSTEM — NOT
ACCUMULATED THROUGH NATURAL SELECTION — REASONS WHY DOMESTIC VARIETIES
ARE NOT MUTUALLY STERILE — TOO MUCH STRESS HAS BEEN LAID ON THE
DIFFERENCE IN FERTILITY BETWEEN CROSSED SPECIES AND CROSSED VARIETIES —
CONCLUSION.

Ir was shown in the fifteenth chapter that when individuals
of the same variety, or even of a distinct variety, are allowed
freely to intercross, uniformity of character is ultimately ac-
quired. 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 domesticated breeds true, or to improve them
by methodical 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, made with some allied race,
and occasionally even by repeated 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 rever-
sion. In a few instances, however, monegrels have retained a
uniform character from their first production.

When two varieties are allowed to cross freely, and one is

174 SUMMARY OF THE

Citar, XTX,

much more numerous than the other, the former wil] ulti-
mately absorb the latter. Should both varieties exist in nearly
equal numbers, it is probable that a considerable period would
elapse before the acquirement of a uniform character; and the
character ultimately acquired would largely depend on pre-
potency of transmission, 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 slaughtered
by man without the least discrimination, some degree of un-
methodical selection would likewise come into action. From
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 go
ereat a degree as has often been supposed, the character of the
offspring in future times; although in some cases it probably
has had a considerable effect.

Domestication, as a general rule, increases the prolificness
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, pies, &ec., are almost
certainly descended from aboriginally distinct stocks, and as
these races are now fully fertile together, or at least incom-
parably more fertile than most species when crossed, we may
with much confidence accept this conclusion.

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 interbreeding. It applies to
the individuals of the same variety but belonging to different
families, to distinct varieties, 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
hybrids cannot be accounted for solely on the principle of com-
pensation from the inaction of the reproductive system. Certam
plants, both of pure and hybrid origin, though perfectly healthy,
have become self-impotent, apparently from the unnatural con-
ditions to which they have been exposed ; and such plants, as
well as others in their normal state, can be stimulated to fer-

ee

Cup. XIX. FOUR LAST CHAPTERS. 175

tility only by crossing them with other individuals of the same
species or even of a distinct species.

On the other hand, long-continued close interbreeding
between the nearest relations diminishes the constitutional
vigour, size, and fertility of the offspring ; and occasionally leads
to malformations, but not necessarily to general deterioration
of form or structure. This failure of fertility shows that the
evil results of interbreeding are independent of the augment-
ation of morbid tendencies common 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
propagated quickly ; but it likewise rests on several carefully
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, and fertility are regained when
animals that have long been interbred are crossed with a dis-
tinct family.

These two great classes of facts, namely, the good derived
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 occa-
sional 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,' and, not long afterwards, that sagacious observer K6l-
reuter, after showing how well the Malvaces are adapted for

' ‘Transactions Phil. Soc. 1799, p.
202. For Kolreuter, see ‘Mém. de
lV Acad. de St. Pétersbourg,’ tom. iii., 1809
(published 1811), p. 197. In reading
C. K. Sprengel’s remarkable work, ‘ Das
entdeckte Geheimniss,’ &., 17 93, it is

fully acute observer failed to understand
the full meaning of the structure of the
flowers which he has so well described,
from not always having before his mind
the key to the problem, namely, the
good derived from the crossing of dis-

curious to observe how often this wonder- _ tinct individual plants.

"176 SUMMARY OF THE Cuap, XIX,

crossing, asks, “an id aliquid in recessu habeat, quod hujus-
cemodi flores nunquam proprio suo pulvere, sed semper eo
aliarum sue speciel impregnentur, merito queritur? Certe
natura nil facit frustra.” Although we may demur to Kél-
reuter’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 contriy-
ances, which favour 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
hermaphrodites, which probably intercross only at long intervals
of time, and with unisexual animals inhabiting somewhat sepa-
rated localities, which can only occasionally come into contact
and pair, the greater vigour and fertility of the crossed offspring
will ultimately prevail in giving uniformity of character to the
individuals of the same species. but 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, we have seen that, on the one hand, it is a widely
prevalent and ancient belief that animals and plants profit from
slight changes in their condition of life; and it would appear
that the germ, in a somewhat analogous manner, is more effectu-
ally stimulated by the male element, when taken from a dis-
tinct individual, and therefore slightly modified in nature, than
when taken from a male having the same identical constitution.
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 repro-
ductive functions are often greatly impaired or quite annulled.
Some groups of animals are more affected than others, but with
apparently capricious exceptions in every group. Some animals
never or rarely couple: some couple freely, but never or rarely
conceive. The secondary male characters, the maternal func-
tions and instincts, are occasionally affected. With plants,
when first subjected to cultivation, analogous facts have been
observed. We probably owe our double flowers, rich seedless

Cuap. XIX. FOUR LAST CHAPTERS. Lit

fruits, and in some cases greatly developed tubers, &e., to
incipient sterility of the above nature combined with a copious
supply of nutriment. Animals which have long been domes-
ticated, and plants which have long been cultivated, can gene-
rally withstand, with unimpaired fertility, great changes in their
conditions of lite; 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 domesticated.

We can in no ease precisely say what is the cause of 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 important bearing on Variability, as we shall
see in a future chapter.

It is impossible not to be struck with the double parallelism
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,
between species,—are highly injurious, as far as the reproductive
system is concerned, and in some few instances as far as consti-
tutional 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

equilibrium, unless disturbed and renovated through the action
of other forces,

In some few cages 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 crossing of
varieties, far from diminishing, generally adds to the fertility of

both the first union and the mongrel offspring. Whether all
VOL. IT. N

178 HYBRIDISM.

Cuap, XIX,

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 experiments, and
many difficulties occur, such as the descent of the various
races from aboriginally distinct species, and the doubts whether
certain forms ought to be ranked as species or varieties. Neyer.
theless, the wide experience of practical breeders proves that
the great majority of varieties, even if some should hereafter
prove not to be indefinitely fertile znter 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 parent-
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 domesticated
varieties of animals and of plants, which differ greatly from each
other in structure, but which are certainly descended from the
same aboriginal 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 im-
passable 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 between 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 ‘Orig
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 vegetable
kingdoms.

Secondly, the sterility of distinct species when first united,

CHAP. XIX, HYBRIDISM, 119

and 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 determining to designate as
varieties all the forms which are quite fertile. This high degree
of fertility is, however, rare. Nevertheless plants, which have
been exposed to unnatural conditions, sometimes become modi-
fied 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 hybrids, 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-capsule often differs much in degree.

Thirdly, 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 species which can
be crossed with ease, but yield hybrids excessively 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.

Hourthly, the degree of sterility often differs greatly in two
species when reciprocally crossed ; for the first will readily fer-
tilise the second; but the latter is incapable, after hundreds of
trials, of fertilising the former. Hybrids produced from reci-
procal crosses between the same two species, likewise sometimes
differ in their degree of sterility. These cases also are utterly
inexplicable 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 general or system-
atic affinity of the forms which are united. For species be-
longing to distinct genera can rarely, and those belonging to
distinct families can never, be crossed. The parallelism, how-
ever, is far from complete; for a multitude of closely allied
species will not unite, or unite with extreme difficulty, whilst
other species, widely different from each other, can be crossed
with perfect facility. Nor does the difficulty depend on ordinary

N 2

180 HYBRIDISM. Caap, XIX,

constitutional differences, for annual and perennial plants
e

deciduous 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 exclusively on the
sexual constitution of the species which are crossed ; or on their
sexual elective affinity, ¢. e. Wahlverwandtschaft of Gartner. Ag
species rarely or never become modified in one character,
without being at the same time modified in many, and as Sys-
tematic affinity includes all visible resemblances and dissimi-
larities, any difference in sexual constitution between two species.
would naturally stand in more or less close relation with their
systematic position.

Sizthly, 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 constitu-
tion 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 hybrid 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 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 themselves 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 resemblance to their two:
parents, in their tendency to reversion, 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

Cnap. XIX, HYBRIDISM. 181

reciprocally dimorphic and trimorphic plants, when illegiti-
mately united. I have had occasion several times to allude to
these plants, and I may here give a brief abstract’ of my
observations. Several plants belonging to distinct orders pre-
sent 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 differently 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 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 fertilised 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 fertile, and twelve are
illegitimate, or more or less infertile.

The infertility which may be observed in various dimorphic
and trimorphic plants, when they are illegitimately 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 species be placed on
the stigma of a flower, and its own pollen be afterwards, even

2 This abstract was published in the my original observations on this point
fourth edition (1866) of my ‘ Origin of have not ag yet been published in
Species ;’ but as this edition will be in detail, I have ventured here to reprint
the hands of but few persons, and as _ the abstract, :

182 HYBRIDISM. Cuap, XIX

aiter 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
several forms of the same species, for legitimate pollen ig strongly
prepotent over illegitimate pollen, when both are placed on the

same stigma. I ascertained this by fertilising several flowers,

first illegitimately, and twenty-four hours afterwards legitimately,
with pollen taken from a peculiarly coloured variety, and al]
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 previously
applied illegitimate pollen. Again, as, in making reciprocal
crosses between the same two species, there is occasionally a
great difference in the result, so the same thing occurs with
trimorphic plants; for instance, the mid-styled form of Lythrum
salicaria could be illegitimately fertilised with the greatest ease
by pollen from the longer stamens of the short-styled form, and
yielded many seeds ; but the latter form did not yield a single
seed when fertilised by the longer stamens of the mid-styled
form.

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 pos-
sible 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 legi-
timate manner. When this is done, there is no apparent reason
why they should not yield as many seeds as did their parents
when legitimately fertilised. 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 @
single seed or even seed-capsule. These illegitimate plants,
which are so sterile, although united with each other in a legi
timate 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

‘

Cuap. XIX. HYBRIDISM. 183

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 unusually great, whilst the steri-
lity 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 variable, so it is in a marked
manner with illegitimate plants. Lastly, many hybrids are
profuse and persistent flowerers, whilst other and more sterile
hybrids produce few flowers, 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 beha-
viour between illegitimate plants and hybrids. It is hardly an
exaggeration to maintain that the former are hybrids, but pro-
duced 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 already 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 trimorphice Lythrum salicaria, and that he determined to
try by crossing whether 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 com-
pletely mistaken.

r + Ls . ° ° :
The facts now given on dimorphic and trimorphic plants are

184 HYBRIDISM. Cuap. XIX,

important, because they show us, firstly, that the physiological
test of lessened fertility, both in first crosses and in hybrids, ig
no safe criterion of specific distinction ; secondly, because we |
may conclude that there must be some unknown law or bond
connecting the infertility of illegitimate unions with that of
their illegitimate 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 crosged
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 struc-
ture of the stigma, and in the number and size of the seeds,
With these differences and no others, either in organisation or
constitution, we find that the illegitimate unions and the ille-
gitimate progeny of these three forms are more or legs sterile,
and closely resemble in a whole series of relations 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 likewise in all probability exclusively due
to differences confined 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 especially led to this
same conclusion by considering reciprocal crosses, in which the
male of one species cannot be united, or can be united with

species in a higher degree than in the converse case. In 80
complex a subject as Hybridism it is of considerable importance —
thus to arrive at a definitive conclusion, namely, that the

sterility which almost invariably follows the union of distinct

= ey OEE

(nap. XIX, HYBRIDISM. 185

species depends exclusively on differences in their sexual con-
stitution.

On the principle which makes it necessary for man, whilst he
is selecting and improving his domestic varieties, to keep them
separate, it would clearly be advantageous to varieties in a state
of nature, that is to incipient species, 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 advan-
tageous, were slowly accumulated. This appears all the more
probable, if we admit that the structural differences between
the forms of dimorphic and trimorphic 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 reference 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 (Muscari comosum) have been rendered con-
spicuous, and apparently in consequence sterile, 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 distinct species of mutual sterility, we
meet with great difficulties. In the first place, it may be
remarked that separate regions are often inhabited by groups of
Species or by single species, which when brought together and
crossed are found to be more or legs sterile ; now it could clearly
have been of no advantage to such separated species to have
been rendered mutually sterile, and consequently this could not
have been effected through natural selection; but it may per-
haps be argued, that, if a species were rendered sterile with

186 HYBRIDISM.

Cuap. XIX,

some one compatriot, sterility with other species would follow
as a necessary consequence. 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 inpotent 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 thig

peculiar state of the reproductive system could not possibly be:
advantageous to either species.

In considering the probability of natural selection having
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 principle 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 dete-
riorated offspring 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 selec-
tion to that higher degree which is common to s0 many
species, and which is universal with species which have been dif-
ferentiated to a generic or family rank, will find the subject extra-
ordinarily 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 indi-
viduals could not have been preserved or selected. Or take
the case of 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 with mutual

infertility and 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 species, for a multitude are mutually

quite barren. With sterile neuter insects we have reason to

a ee

.

Cuap. XIX. HYBRIDISM. 187

believe that modifications in their structure have been slowly
accumulated by natural selection, from an advantage having
been thus indirectly given to the community to which they
belonged 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 preserva-
tion. 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 accu-
mulated by means of natural selection.

With plants, it is possible that the case may be somewhat
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 deposited on the stigma of the same
variety, should become by spontaneous variation in ever so
slight a degree prepotent over the pollen of other varieties, this
would certainly 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 advantage would be. We
know from the researches of Giirtner 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 advantageous to a species
in process of formation, so the sterility consequent on prepo-
tency would at the same time be augmented; and the final
result would be various degrees 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
sexual element of the prepotent male of her own variety obli-
terated the effects of the access of previous males belonging
to other varieties; but we have no reason to believe, at least

188 HYBRIDISM. Cuap, XIX,

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 rendered sterile by a different process. From this
consideration, and remembering that species which have never
co-existed in the same country, and which therefore could not
have received any advantage from having been rendered mn.
tually 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 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 organisa- °
tion. By a quality arising incidentally, I refer to sueh cases
as different species of animals and plants being differently
affected by poisons to which they are not naturally exposed;
and this difference in susceptibility is clearly 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 structural or functional dif-
ferences in their woody tissues. We need not feel surprise at
sterility incidentally resulting from crosses between distinct
species,—the modified descendants of a common progenitor,—
when we bear in mind how easily the reproductive system 18
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-fertility from

a

ae

Cap. XIX, HYBRIDISM. 189

being grafted on a distinct spectes—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 dis-
cussion: 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 characters 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? We can, to a certain extent, 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 conditions to which domesticated animals

_ and cultivated plants have been subjected, have had go little

tendency towards modifying the reproductive system in a

‘manner leading to mutual sterility, that we have good grounds

for admitting 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 far is culti-
vation from giving a tendency towards 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 fertilising, 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 improbable 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 in-

190 HYBRIDISM. CuAP, XIX

duced. Thus, as I believe, we can understand why with domes-
ticated 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 experimentalists with varie-
ties of the gourd and melon, and by Kélreuter with one kind of

tobacco.
With respect to varieties which have originated in a 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
(Anagallis arvensis) 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 in-
fertile when crossed, but why this has so generally 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 difference in the result. For we
know how commonly wild animals and plants, when taken from
their natural conditions and subjected to captivity, are rendered
sterile; and the reproductive functions of organic beings which
have always lived and been slowly modified under natural con-
. ditions would probably in like manner be eminently sensitive to
the influence of an unnatural cross. Domesticated productions,
on the other hand, which, as shown by the mere fact of their
domestication, were not originally highly sensitive to changes
in their conditions of life, and which can now generally resist

CuaP, XIX. HYBRIDISM. 191

with undiminished fertility repeated changes of conditions,
might be expected to produce varieties, which would be little
liable to have their reproductive powers injuriously affected by
the act of crossing with other varieties which had originated 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 colour 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 manner, and I am not aware
that any difference in this respect 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 differences
are apparently wholly or in chief part incidental on other con-
stitutional 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, how-
ever serviceable they may indirectly be in keeping the inha-
bitants of the same country distinct, be thought of such para-
mount importance, 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.

192 SELECTION. Cuap, XX,

CHAPTER XxX.

SELECTION BY MAN.

SELECTION A DIFFICULT ART — METHODICAL, UNCONSCIOUS, AND NATURAL SELECTION
—RESULTS OF METHODICAL SELECTION — CARE TAKEN IN SELECTION — SELECTION
WITH PLANTS —— SELECTION CARRIED ON BY THE ANCIENTS, AND BY SEMI-CIVILISED
PEOPLE—UNIMPORTANT CHARACTERS OFTEN ATTENDED TO —UNCONSCIOUS SELEC-
TION — 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,

Tue 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, absolutely depends on the
variability of organic beings. Without 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 pre-
ceded our present subject, as well as the previous subjects of
inheritance, crossing, &c.; but practically the present arrange-
ment has been found the most convenient. Man does not
attempt to cause variability; though he unintentionally effects
this by exposing organisms to new conditions of life, and by
crossing breeds already formed. But variability being granted,
he works wonders. Unless some degree of selection be exercised,
the free commingling of the individuals of the same variety sooD
obliterates, as we have previously seen, the slight differences
which may arise, and gives to the whole body of individuals
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

* —_ —_ 72 —

|
;

Cuap, XX, SELECTION. 193

of the direct action of the conditions of life we shall in a future
chapter recur. :

When animals or plants are born with some conspicuous and
firmly inherited new character, selection is reduced to the pre-
servation 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 superi-

ority in am 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 endowed 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 breeders, whose
skill and judgment have been proved by their success at exhi-
bitions, have shown me their animals, which appeared all alike,
and have assigned their reasons for matching this and that indi-
vidual. The importance of the great principle of Selection
mainly lies in this power of selecting scarcely appreciable
differences, which nevertheless are found to be transmissible,
and which can be accumulated until the result is made manifest
to the eyes of every beholder. | ne oe

The principle of selection may be conveniently divided into
three kinds. Methodical selection is that which guides a man
who systematically endeavours to modify a breed according to
some predetermined standard. -Unconseéous 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 gene-
rally 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
VOL. IL

O

194 SELECTION. Cuap, XX,

unconsciously. Lastly, we have Natural 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 clearly shown by
our exhibitions of improved quadrupeds and fancy birds. With
respect to cattle, sheep, and pigs, we owe their great improve-
ment 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 sagacious
and experienced observer, writes,” the principle 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® says, “In the anatomy of the shoulder
“modern breeders have made great improvements on the
“ Ketton shorthorns by correcting the defect in the knuckle or
‘ shoulder-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 pigs‘ says: “ The legs

1 The term unconscious selection has grains of sand of equal size.
been objected to as a contradiction ; but 2 On Sheep, 1838, p. 60.
see some excellent observations on this 3 Mr. J. Wright on Shorthorn Cattle,
head by Prof. Huxley (‘Nat. Hist. in ‘Journal of Royal Agricult. Soc.,
Review,’ Oct. 1864, p. 578), who re- vol. vii. pp. 208, 209.
marks that when the wind heaps up 4H. D. Richardson on Pigs, 1847;

sand-dunes it sifts and wnconsciously p. 44.
selects from the gravel on the beach

Cuap, XX. METHODICAL SELECTION. 195

“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 therefore 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 systematic
care taken in selecting animals, and of the necessity of having a
clear and almost prophetic vision into futurity. Lord Spencer's
skill and judgment were well known; and he writes “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 Bakewell
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 standard of perfection was
fixed, according to which the London fanciers tried to breed the
several sub-varieties.’ A great winner of prizes at the Pigeon-
shows,* in describing the Short-faced Almond Tumbler, says,
“There are many first-rate fanciers who are particularly partial
“to what is called the goldfinch-beak, which is very beautiful ;
| “ others say, take a full-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
P. “a good head and beak, provided, as I said before, it is judi-
“ciously done; others take an oat; but as I think the eold-
“finch-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 ex-

> «Journal of R. Agricult. Soe.” vol. i. p. 24. ® On Sheep, pp. 520, 319,
7 Loudon’s « Mag. of Nat. Hist.” vol. Viii., 1835, p. 618.
* “A Treatise on the Art of Breeding the Almond Tumbler,’ 1851, p. 9.

og

196 SELECTION. CHAP, XX,

ternal 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,’ 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
“orain of the meat” in cattle, and its being well marbled with
fat,° and the greater or less accumulation of fat in the abdomen
of our sheep, have been attended to with success. So with
poultry, a writer," 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 ” “the breeding of
« bulls %§ 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 general 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.% “So important is the proper selection 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 upo2
“a table that his wool and form may be minutely observed.

® «Recreations in Agriculture, vol. Agricult. Soc.,’ quoted in ‘ Gard. Chro-

ii. p. 409. ° ro - . nicle,’ 1844, p. 29.
10 Youatt on Cattle, pp. 191, 227. 13 Simmonds, quoted in ‘ Gard.
1 Ferguson, ‘Prize Poultry” 1854, Chronicle, 1855, p. 637. And for the
p. 208. a: . second quotation, see Youatt on Sheep,

% Wilson, in ‘ Transact. Highland _ p. 171.

Cuap, XX. METHODICAL SELECTION. 197

* «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 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 igs
“ 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 invented to measure
accurately the thickness of the fibres; and “an Austrian fleece
has been produced of which twelve hairs ‘equalled i in thickness
one from a Leicester sheep.” pk |
Throughout the world, wherever silk is produced, the greatest
care is bestowed on selecting the cocoons from which the moths
for breeding are to be reared. A careful 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.”
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 by law from producing silk."®

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 disputing 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 fancier, who writes, “I would here particularly guard

‘* Robinet, ‘ Vers a Soie? 1848, p. 271. WV “The Poultry Chronicle,’ vol. i
® Quatrefages, ‘Les Maladies du 1854, p. 607.
Ver & Soie, 1859, p- 101. . 8 J. M. Eaton, ‘ A Treatise on Fancy
** M. Simon, in ‘Bull. de la Soc. Pigeons? 1852, p. xiv. and ‘ A Treatise
d’Acclimat.,’ tom. ix., 1862, p. 221. on the Almond Tumbler,’ 185], p. 11.

Bi
i ita ee

198 : SELECTION. ’ CHAP, XX,

“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 know-
“ ledge of fancy pigeons; but there are many more who labour
“ under the delusion of supposing 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 says, “there are some young fanciers
‘“‘ who are over-covetous, who go for all the above five properties
“at once; they have their reward 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 Exhibitions,
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. Corringham remarks," during the
last twenty years have undergone, 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 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

19 * Journal Royal Agricultural Soc.,’ vol. vi. p. 22.

Cuar. XX. METHODICAL SELECTION, 199

fowls, turkeys, ducks, and geese is notorious; “six-pound
ducks are now common, whereas four pounds was formerly 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
an almond tumbler’s body, “a triumph,” says another fancier,
“of which he may be justly proud.” ”

Mr. Tollet, of Betley Hall, selected cows, and especially bulls,
descended from good milkers, for the sole purpose 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 proportion of four to
three. Here is a curious case of steady but slow progress,
with the end not as yet fully attained: in 1784 a race of 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 proportion 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 much care to pre-
vent crosses as with animals or unisexual plants; but with
some plants, such as peas, this care does not seem to be neces-
sary. With all improved plants, excepting of course those
which are propagated by buds, cuttings, &c., it is almost indis-
pensable 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, Experienced horticulturists and agriculturists inces-

santly urge every one to preserve the finest plants for the
production of seed.

Although plants often present much more conspicuous varia-
tions than animals, yet the closest attention is generally requisite
to detect each slight and favourable change. Mr. Masters
relates” how “ many a patient hour was devoted,” whilst he was

*0 ¢ Poultry Chronicle,’ vol, li., 1855, p. 596.
* Isid. Geoffroy St. Hilaire, ‘Hist. Nat. Gén.,’ tom, iii. p. 254.

99
a

* *Gardener’s Chronicle, 1850, p, 198,

200 SELECTION.

CHAP, XX,

young, to the detection of differences in peas intended for seed.
Mr. Barnet” remarks that the old scarlet American strawberry
was cultivated for more than a century without producing a,
single variety ; and another writer observes how singular it wag
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
process of selection has seldom or never been long continued.

_ It may be worth while to give a few examples of methodical
selection with plants; but in fact the great improvement of all
our anciently cultivated plants may be attributed to selection
long carried on, in part methodically, and in part unconsciously.
T have shown in a former chapter how the weight of the goose-
berry has been increased by systematic selection and culture.
The flowers of the Heartsease have been similarly increased in
size and regularity of outline. With the Cineraria, Mr. Glenny*
“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 impossible, 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 so.” The doubling
of flowers has several times been effected by careful selection:
the Rev. W. Williamson,” after sowing during several years:
seed of Anemone coronaria, found a plant with one additional
petal ; he sowed the seed of this, and by perseverance in the:
same course obtained several varieties with six or seven rows of
petals. The single Scotch rose was doubled, and yielded eight
good varieties in nine or ten years.* The Canterbury bell
(Campanula medium) was doubled by careful selection in four
generations.” In four years Mr. Buckman,” by culture and

. 23 «Transact. Hort. Soc.,’ vol. vi. p. 26 «Transact, Hort, Soc.” vol. iv. P+
152. 285.

4 ¢ Journal of Horticulture,’ 1862, p. 7 Rey.’ W. -Bromphead: in * Gard,
369. Chronicle,’ 1857, p. 550. -

25 «Transact. Hort. Soc.,’ vol. iv.p. 381. } 28 «Gard, Chronicle, 1862, p. 721.

ats

: Cuap, XX. BY THE ANCIENTS. 201

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 days.” 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 regu-
larly tested, and the best roots saved for the production of

seed.”

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 practised selection of any kind. Undoubt-
edly 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 recognised

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 hereafter 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,’! who has discussed all the passages
in relation to breeding in the Old Testament, concludes that

la

———

Bei Dr. Anderson, in ‘The Bee,’ vol. 30 Godron, ‘De I’Espece,’ 1859, tom.
vi. p. 96; Mr. Barnes, in ‘Gard. ii. p.69; ‘Gard. Chronicle, 1854, p. 258.
Chronicle, 1844, p. 476. 31 On Sheep, p. 18. age

, 2

202 SELECTION, Cuap, XX,

at this early period “some of the best principles of breeding
must have been steadily and long pursued.” It was ordered,

according to Moses, that “Thou shalt not let thy cattle gender
with a diverse kind ;” but mules were purchased,” so that at this
early period other nations must have crossed the horse and ass.
It is said®* that 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 superior
to any in the surrounding countries.” Homer (Book vy.) speaks
of Aineas’s horses as bred from mares which were put to the
steeds of Laomedon. Plato, in his ‘ Republic,’ says to Glaucus,
“T 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.** Alexander the Great selected the finest
Indian cattle to send to Macedonia to improve the breed.®
According to Pliny,® King Pyrrhus had an especially valuable
breed of oxen; and he did not suffer the bulls and cows to
come together till four years old, that the breed might not
degenerate. Virgil, in his Georgies (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 detailed instructions about breeding
fowls: ‘‘ Let the breeding hens therefore be of a choice colour,
“a robust body, square-built, full-breasted, with large heads,
“ with upright 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 ;

*° Volz, ‘Beitrige zur Kulturge- logical Review,’ May 1864, p. 101.

schichte,’ 1852, s. 47. 3 Volz, ‘ Beitrage,’ &c., 1852, s. 80.
33 Mitford’s ‘ History of Greece,’ vol. 3° ¢ History of the World,’ ch. 45.
1; p.73. 37 “Gardener’s Chronicle,’ 1848, p.

%* Dr, Dally, translated in ‘Anthropo- 23,

-

Cuap. XX. BY THE ANCIENTS. 203

and Cesar states that they paid high prices to merchants for
fine imported horses.* 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.”
Coming down the stream of time, we may be brief. At about
the beginning of the ninth century Charlemagne 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 mares.” Even in a country so little civilised
as Ireland during the ninth century, it would appear from some

ancient verses, 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 chosen stallions from
Flanders.” On June 16th, 1305, the Prince of Wales wrote
to the Archbishop of Canterbury, begging for the loan of any
choice stallion, and promising its return at the end of the
season.“ 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
magistrates, at Michaelmas, should scour the heaths and com-
mons, and destroy all mares beneath a certain size.4 Some of
our earlier kings passed laws against the sl aughtering rams of any
good breed before they were seven years old, so that they might

38 Reynier, ‘De lEconomie deg 1860, p. 11.

Celtes, 1818, pp. 487, 503. # Col. Hamilton Smith, ‘ Nat.
39 Le Couteur on Wheat, p. 15. Library,’ vol. xii., Horses, pp. 135, 140.
*° Michel, ‘ Des Haras,’ 1861, p. 84. 43 Michel, ‘Des Haras,’ p. 90.

“ Sir W. Wilde, an ‘Essay on Un- 44 Mr. Baker, ‘ History of the Horse,’

manufactured Animal Remains, &e., ‘Veterinary,’ vol. xiii. p, 423.

204 SELECTION Cuap, XX,

have time to breed. In Spain Cardinal Ximenes issued, in 1509,
regulations on the selection of good rams for breeding.”

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. Markham
in 1631 tells the breeder “to elect the largest and coodliest
conies,” and enters into minute details... Even with respect

_ to seeds of plants for the flower-garden, Sir J. Hanmer writing

about the year 1660“ says, in “choosing seed, the best seed is
the most weighty, and is had from the lustiest and most vigor-
ous 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 hundred 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 same
“time. . In the same manner he treats all his other plants,
“ varying the circumstances according to their nature.” -

In the great work on China published in the last century by
the Jesuits, and which is chiefly compiled from ancient Chinese
encyclopedias, 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 separate.” The same principles were
applied by the Chinese to various plants and fruit-trees.® - An

45 M. Abbé Carlier, in ‘ Journal de 46 « Gardener’s Chronicle,’ 1843, p. 389.

Physique,’ vol. xxiv., 1784, p. 181: this 47 Communications to Board of Agri-

memoir contains much information on culture, quoted in Dr. Darwin’s ‘ Phyto-
the ancient selection of sheep; and is logia, 1800, p. 451.

my authority for rams not being killed -. 48 ‘Mémoire sur les Chinois,’ 1786,
young in England. tom. xi. p. 55; fom. v. p. 507.

Guar, XX. BY SEMI-CIVILISED PEOPLE. 905

imperial edict recommends 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. Even with flowers, the tree pony (P. moutan) has
been cultivated, according to Chinese traditions, for 1400 years ;
between 200 and 800 varieties have been raised, which are
cherished like tulips formerly were by the Dutch.” |

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 absolutely 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® horses are often born in Paraguay 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
1770, was preserved and propagated it 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 conspicuous va-
riations have been preserved, and others have been habitually
destroyed, in these countries, which are go little favourable for
careful selection. We have also seen that the inhabitants some-
times introduce cattle on their estates to prevent the evil effects of
close interbreeding. 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

9 «Recherches sur Agriculture des vol. xii, 0,253:

Chinois,’ par L. D’Hervey-Saint-Denys, °! ‘Mem. de l’Acad.’ (divers savans),
1850, p. 229. With respect to Khang-hi, tom, vi., 1835, p. 333.
see Huc’s ‘ Chinese Empire,’ p. 311. 52 «Des Quadrupedes du Paraguay,

_ °® Anderson, in ‘Linn, Transact.,’ 1801, tom. ii, p. 338, 371.

206 SELECTION. Cuap, XX,

“(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.” According to Pallas the Mongoliangs
endeavour to breed the Yaks or horse-tailed buffaloes with
white tails, for these are sold to the Chinese mandarins ag fly-
flappers ; and Moorcroft, about seventy years after Pallas, found
that white-tailed animals were still selected for breeding.

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 Canide, as did the ancient Gauls, according
to Pliny. ‘This was done to give their dogs 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 polecat, “to give them 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 Banteng
(Bos sondaicus).° 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 ;*° 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. Schom-
burgk informs me,” 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 proved bad or useless,

°8 «The Great Sahara,’ by the Rev. Field,’ 1859, p. 196: for Varro, sce

H. B. Tristram, 1860, p. 238. Pallas, ut supra.

54 Pallas, ‘ Act, Acad. St. Petersburg,’ 56 Krman’s ‘ Travels in Siberia,’ Eng.
1777, p. 249; Moorcroft and Trebeck, translat., vol. i. p. 453.
‘Travels in the Himalayan Provinces,’ 57 See also ‘Journal of R. Geograph.
1841. Soc.,’ vol, xiii. part i. p. 65.

°° Quoted from Raffles, in the ‘Indian

say

Cap. XX. BY SEM]J-CIVILISED PEOPLE. 207

he was not killed, but was left to die from sheer neglect,
Hardly any nation 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 associated
with white men, show great anxiety to improve their animals:
they “always choose the larger and stronger 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.* 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,”
The power of discrimination which these Savages possess is
wonderful, and they can recognise to which tribe any cattle
belong. Mr. Andersson further informs me that the natives
frequently 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 recorded, is that
given by Garcilazo de la Vega, a descendant of the Incas, as
having been practised in Peru before the country was subjugated
by the Spaniards.” The Incas annually held great hunts, when
all the wild animals 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

*® Livingstone’s ‘First Travels, Pp. 59 Andersson’s ‘Travels in South
191, 439, 585: sce also ‘Expedition to Africa’ pp. 232, 318, 319.
the Zambesi,’ 1865, p. 495, for an 60 Dr. Vavasseur, in ‘Bull. de la

analogous case respecting a good breed Soc. d’Acclimat.,’ tom. vili., 1861, p,
of goats, 136,

‘208 SELECTION, ‘Car, XX

were likewise killed; “but the young females, with a certain
number of males, selected 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 system of that which our Scottish sportsmen
are accused of following, namely, of steadily killing the finest
stags, thus causing the whole race to degenerate." In regard
to the domesticated Mamas and alpacas, they were separated
in the time of the Incas according to colour; and if by chance
cone in a flock was born of the wrong colour, it was eventually
_put into another flock. | |

In the genus Auchenia there are four forms,—the Guanaco and
Vicuna, found wild and undoubtedly distinct species; the Llama

and Alpaca, known only in a domesticated 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, notwith-
standing 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 propagation,
adduces arguments® which seem to me conclusive, that the
Ilama 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 surprising in the great amount of
change which they have undergone. » 3 , ;

It appeared to me at one time probable that, though ancient
and semi-civilised people might have attended to the improve-
ment 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 every-
where reigns supreme, and man is apt 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 Damaras of South Africa value their cattle for uniformity

61 «The Natural History of Dee Side,’ 1855, p. 476.
62 « Bull, de la Soc. d’Acclimat.,’ tom, vii., 1860, p. 497.

Cuap, XX. OF TRIFLING CHARACTERS. 209

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 a
been valued, and consequently preserved. With respect to cattle,
“an early record,” according 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 subjugation 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 com-
“ petition sprung up for her possession, and she realised a
“considerable price.” With respect to sheep, the Chinese
prefer rams without horns ; the Tartars prefer them with

- spirally wound horns, because the hornless are thought to lose

courage.® Some of the Damaras will not eat the flesh of horn-
less sheep. In regard to horses, at the end of the fifteenth
century animals of the colour described as Wart pommé 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 ;”* the Arabs also, as we have seen, despise dun-coloured
horses. 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.®
In Guiana, as I am informed by Sir R. Schomburgk, the
aborigines will not eat the flesh or eges of the fowl, but two

* « Cattle,’ p. 48, Jesuits), 1786, tom. xi. p. 57.

_ hivingstone’s’ Travels, p. 376; © 68 . Michel, « Des Earns, pp: 47, 50.
Andersson, ‘ Lake Ngami,’ 1856, p. 222, Col. Hamilton Smith, Dogs, in
With respect to the sale in Kaffraria, “Nat, Lib.,’ vol. x. p. 103.

see Quarterly Review,’ 1860, p. 139, 8 Azara, ‘Quadrupedes du Paraguay,’
°° Mémoire sur les Chinois’ (by the tom, ii. p. 824,

VOL. II. r

|

210 SELECTION. Cuar, XX,

races are kept distinct merely for ornament. Inthe 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 peculiarities 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 onein Yorkshire.” In one of the Berkshire sub-breeds,
it is said, “‘the white should be confined to four white feet,
“a white spot between the eyes, and a few white hairs behind
“each shoulder.” Mr. Saddler possessed “ three hundred pigs,
“ every one of which was marked in this manner.” Marshall,
towards the close of the last century, 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 fashionable for the last twenty years.’ 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 curva-
ture and tint, so much so that mechanical means are applied if
they take a wrong direction; but the inhabitants “consider it
“ of the highest importance that the nostrils of the bull should
“be flesh-coloured, and the eyelashes light; this is an indis-
“ pensable condition. A calf with blue nostrils would not be
“ purchased, or purchased at a very low price.” 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 individuals, without
any conscious intention on his part of altering the breed. It 1s
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

69 Sidney’s edit. of Youatt, 1860, pp. 24, 25.
70 «Rural Economy of Yorkshire,’ vol, ii. p. 182.
71 Moll et Gayot, ‘Du Beeuf,’ 1860, p. 547.

Gain ex UNCONSCIOUS SELECTION, 211

methodical 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 VIIT.’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 families. This at least is the conclusion of
those who have closely studied the subject of the conscription ;
and it is certain that since Napoleon’s 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 unusually short beak,
or one with the tail-feathers unusually developed, although
he bred from these birds with the distinct intention of propa-
gating 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 astonish-
ment, 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 Pigeon, and from the comparison of birds
brought from distant countries. Sigs

So it has been with dogs; our present fox-hounds differ 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

PZ

21S SELECTION. Cuap, XX,.

closely resemble any native dog now found in the countries
whence they were brought. These changes have been effected
partly by crosses; but mm every case the result has been
governed by the strictest selection. Nevertheless there ig 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
from large spaniels, have been greatly modified in accordance
with fashion and the desire for increased speed. Wolves have
become extinct, deer have become rarer, bulis 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 followed.
methodically, and our horses can now easily beat their pro-
genitors. The increased size and different appearance 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,” the introduction in Oliver Cromwell’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 carefully selection must have been.
attended to; for without such care, all traces of so small an
infusion of Eastern blood would soon haye been absorbed and

@ «The India Sporting Review,’ vol. ii. p. 181; ‘The Stud Farm,’ by Cecil, p. 58:
¥83.* The Horse’ p, 29.

‘CHAP XX, UNCONSCIOUS SELECTION. 213

lost. Notwithstanding 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 longer and earlier
period, has ended in giving us the best breed of horses in the world.
Macaulay remarks, “‘Two men whose authority on such
“ subjects was held in great esteem, the Duke of Newcastle and
“Sir John Fenwick, pronounced that the meanest hack ever
“ imported from Tangier would produce a finer progeny than
“could be expected from the best sire of our native 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 appearance
from any natural species, and which from its size has so
astonished many Eastern princes, was probably formed by the
heaviest and most powerful animals having been selected
during many generations in Flanders and England, but without
the least intention or expectation of creating a horse such as
we now see. If we go back to an early period of history, we
behold in the antique Greek statues, as Schaaffhausen has
remarked,” a horse equally unlike a race or dray horse, and dif-
fering from any existing breed.

The results of unconscious selection, in an early stage, are
well shown in the difference between the flocks descended 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 original 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 differ-
“ence between the sheep possessed by these two gentlemen
“is so great, that they have the appearance of being quite
“ different varieties.” I have seen several analogous and well-

i ‘History of England? vol. i. p. 316.
75 ‘Ueber Bestindigkeit der Arten” 76 Youatt on Sheep, p. 315.

214 SELECTION.

Cuap. XX,

marked cases with pigeons: for instance, I had a family of
barbs, descended from those long bred by Sir J. Sebright, and
another family long bred by another fancier, and the two
families plainly differed from each other. Nathusius—and
more competent witness could not be cited—observes that,
though the Shorthorns are remarkably uniform in appearance
(except in colouring), yet that the individual character and
wishes of each breeder become impressed on his cattle, so that
different herds differ slightly from each other.” The Hereford
cattle assumed their present well-marked character soon after
the year 1769, through careful selection by Mr. Tomkins,® and
the breed has lately split into two strains—one strain having
a white face, and differing slightly, it is said,”® in some other
points; 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. When we bear in mind how
rapidly all animals 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 inevitable
that his individual frame of mind will influence the character
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 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. Savages often suffer from
famines, and are sometimes expelled 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

‘7 ‘Ueber Shorthorn Rindvieh, 1857, , 79 ‘Quarterly Review,’ 1849, p. 392.

8. 1. 80 H. von Nathusius, ‘ Vorstudien
8 Low, ‘Domesticated Animals,’ ... . Schweineschiidel,’ 1864, s. 140.

1845, p. 363.

Cuap, XX. JNCONSCIOUS SELECTION, 215

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 occasional preservation in the two countries of the most
useful animals would ultimately lead to the formation of two
widely distinct breeds.

With plants, from the earliest dawn of civilisation, the best
variety which at each period was known would generally 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. Weat the present day profit by a course
of selection occasionally and unconsciously carried on during
thousands of years. This is proved in an interesting manner
by Oswald Heer’s researches on the lake-inhabitants of Switzer-
land, as given in a former chapter; for he shows that the erain
and seed of our present varieties of wheat, barley, oats, peas,
beans, lentils, and poppy, exceed in size those which were culti-
vated in Switzerland during the Neolithic and Bronze periods.
These ancient people, during the Neolithic period, possessed also
a crab considerably larger than that now growing wild on the
Jura." The pears described by Pliny were evidently extremely
inferior in quality to our present pears. We can realise the effects
of long-continued selection and cultivation 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

81 See also Dr. Christ, in ‘ Riitimeyor’s PfahTbauten,’ 1861, s. 226.

216 SELECTION, Citar, XX,

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, Buffon,” 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 rejected, not only by a florist but by
a village gardener. Since the time of Buffon the work of
improvement has steadily and rapidly gone on. Every florist
who compares our present flowers with those figured in books
published not long since, is astonished at the change. A well-
known amateur, in speaking of the varieties of Pelargonium
raised by Mr. Garth only twenty-two years before, remarks,
“what a rage they excited: surely we 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 flower,“ 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 improve-
ment being guided by fashion, and by the successive modifica-
tions which the flower slowly underwent.” A steady and gradual
change has been noticed in many other flowers: thus an old
florist," after describing the leading varieties of the Pink which
were grown in 1818, adds, “the pinks of those days would now
“be scarcely grown as border-flowers.” The improvement of

8 The passage is given ‘Bull. Soc. 85 See Mr. Wildman’s address to the
d’Acclimat.,’ 1858, p. 11. Floricult. Soc., in ‘Gardener’s Chro-
8 « Journal of Horticulture,’ 1862, p. nicle,’ 1843, p. 86.
394, 86 «Journal of Horticulture, Oct.

St *Gardener’s Chronicle,’ 1857, p. 85. 24th, 1865, p. 239,

—

a i a

(Hap, XX. SELECTION. ys is |

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 1549."

Effects of Selection, as shown by the parts most valued by man
presenting the greatest amount of Difference.—The power of long-
continued selection, whether methodical or unconscious, or both
combined, is well shown in a general way, namely, by the
comparison of the differences 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. What-
ever 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 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. Grallesio has made the same
observation. 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.®

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 dif-
ference between widely different organs is necessarily vague ;
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 differ 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

% Prescott’s ‘Hist. of Mexico,’ vol.
iL, p. 61.

*8 Sageret, ‘Pomologie Physiolo-
gique,’ 1830, p. 47; Gallesio, ‘Teoria
della Riproduzione? 1816, p. 88;
Godron, ‘De ’Espece,’ 1859, tom. ii. pp.

63, 67, 70. In my tenth and eleventh
chapters I have given details on the
potato; and I can confirm similar re-
marks with respect to the onion. I have
also shown how far Naudin concurs
in regard to the varieties of the melon.

SELECTION, CHAPE XX

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 culti-
vated in our flower-gardens for ornament; or if we compare
their seeds with those of the varieties of maize, peas, beans, &e.,
which 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 the Pots sans parchemin
differ much more in their pods, and these are eaten and yalued.
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 corre-
sponds 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 fruit. If, as is highly probable, the peach is the modi-
fied descendant of the almond, a surprising 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 homological nature may
be) and the seed, when one part is modified, so generally is the
other, but by no means necessarily in the same degree. With

Cirap, XX. SELECTION. 919

the plum-tree, for instance, some varieties produce plums which
are nearly alike, but include stones extremely dissimilar in
shape; whilst conversely other varieties produce dissimilar fruit
with barely 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 organs
which are not manifestly related, through some unknown bond
vary together, and are consequently liable, without any inten-
tion 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 ereatly
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 succes-
sively preserved, and thus continually augmented; whilst other
variations, excepting such as inevitably appeared through corre-
lation, were neglected and lost. Hence we may infer that most
plants might be made, through long-continued selection, to
yield races as different from each other in any character

‘220 SELECTION. CHAP, bw. 4

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 described as an extremely stupid animal.®
Blumenbach remarks that “many dogs, such as the badger-
“dog, have a build so marked and so appropriate for particular
‘purposes, that I should find it very difficult to persuade myself
“that this astonishing figure was an accidental consequence of
“degeneration.” °° But had Blumenbach reflected on the great
principle of selection, he would not have used the term degene-
ration, and he would not have been astonished that dogs and
other animals should become excellently adapted for the service
of man.

On the whole we may conclude that whatever part or cha-
racter 1s 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—that character will almost
invariably be found to present the greatest amount of difference
‘both in kind and degree. And this result may be safely attributed
to man 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 im-
‘portant subject. » With animals such as the giraffe, of which

*° Godron, ‘ De P Espéce,’ tom. ii. p. 27.
9 «The Anthropological Treatises of Blumenbach,’ 1865, p. 292.

Cuap, XX. SELECTION. o5T

the whole structure is admirably co-ordinated for certain pur-
poses, 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. No doubt, ifthe 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 modified would, during a dearth, have a
slight advantage, and be enabled to browse on higher twigs, and.
thus survive. A few mouthfuls more or less every day would
make all the difference between life and death. By the repeti-
tion of the same process, and by the occasional intercrossing
of the survivors, there would be some progress, slow and fluc-
tuating 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 would 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 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-ordinated 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
variability 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

222 SELECTION. Cuap. XX,

present perfect type. By small and doubtful steps such as these,
nature, as we may confidently believe, has progressed on her
erand march of improvement and development.

A similar line of reasoning is as applicable to separate organs
as to the whole organisation. A writer” has recently maintained
that “it is probably no exaggeration to suppose that, in order to
“improve such an organ as ilies eye at all, it must be improved
“in ten different ways at once. And the improbability of any
“ complex 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 mathematical 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 simultaneously altered, in order that the organ should
remain serviceable. ‘

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 sensitiveness of
the retina, and is known to be inherited. Now, if a bird, for
Instance, received some great advantage from seeing well in
the twilight, all the individuals with the most sensitive retina
would succeed best and be the most likely 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 modifications were strictly simul-
taneous? ‘These individuals would subsequently intercross and
blend their respective 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 advanced 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 cer-
tain conditions, abruptly gained. The Fuegians on board the

1 Mr. J. J. Murphy in his opening given by the Rev. C. Pritchard, Pres.
address to the Belfast. Nat. Hist. Soc., Royal Astronomical Soc., in his sermon
as given in the Belfast Northern Whig, (Appendix, p. 33) preached before the
Nov. 19, 1866. Mr. Murphy here fol- British Association at Nottingham,
lows the line of argument against my 1866.
views previously and more cautiously :

CHAP. XX. SELECTION. 923

Beagle could certainly see distant objects more distinctly than
our sailors with all their long practice; I do not know whether
this depends on nervous sensitiveness or on the power of
adjustment in the focus; but this capacity for distant vision
might, it is probable, be slightly augmented by successive modi-
fications of either kind. Amphibious animals, which are enabled
to see both in the water and in the air, require and possess, as
M. Plateau has shown,” eyes constructed on the following 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 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 cornea or crystalline, and then in
the density of the humours, or conversely, might successively
occur, and would be advantageous to the animal whilst under
water, without serious detriment to its power of vision in the air.
It is of course impossible to conjecture by what steps the fun-
damental 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 probably passed, can by the aid of analogy be indi-
cated, as I have attempted to show in my ¢ Origin of Species.’

* On the Vision of Fishes and Amphibia, translated in ‘ Annals and Mag. of
Nat. Hist., vol. xviii., 1866, p. 469, °3 Fourth edition, 1866, p, 215.

224 SELECTION.

CHAPTER XXL

SELECTION, continued.

NATURAL SELECTION AS AFFECTING DOMESTIC PRODUCTIONS — CHARACTERS WHICE
APPEAR OF TRIFLING VALUE OFTEN OF REAL IMPORTANCE — CIRCUMSTANCES
FAVOURABLE TO SELECTION BY MAN — FACILITY IN PREVENTING CROSSES, AND
THE NATURE OF THE CONDITIONS — CLOSE ATTENTION AND PERSEVERANCE INDIS-
PENSABLE — 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 IMPORTANT — MANNER IN WHICH DOMESTIC RACES

HAVE ORIGINATED — SUMMARY.

Natural Selection, or the Survival of the Fittest, as affecting
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 dif-
fering in constitution and in various characters would succeed
best, and so be naturally selected. Hence perhaps it is that the
few domesticated animals kept by savages partake, as has been
remarked by more than one writer, of the wild appearance of
their masters, and likewise resemble natural species. Even in
long-civilised countries, at least in the wilder parts, natural
selection must act on our domestic races. It is obvious that
varieties, having very different habits, constitution, and struc-
ture, 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
“unequal to the task of supporting such heavy-bodied sheep ;
“and they gradually dwindled away into less and less bulk:

Pa ae eee ee

uap, XXI. NATURAL SELECTION. 995

“each generation was inferior to the preceding one; and when
“the spring was severe, seldom more than two-thirds of the
“lambs. survived the ravages of the storms.”' So with the
mountain cattle of North Wales and the Hebrides, 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 Cireassia, 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 strongest and most vigorous alone survive.”

Every one must have been struck with the surpassing grace,
strength, and vigour of the Game-cock, with its bold and con-
fident air, its long, yet firm neck, compact body, powerful and
closely pressed wings, muscular thighs, strong beak massive at
the base, dense and sharp spurs set low on the legs for
delivering the fatal blow, and its compact, glassy, 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
selection, but in addition, as Mr. Tegetmeier has remarked, by
a kind of natural selection, for the strongest, most active and
courageous birds have stricken down their antagonists in the
cockpit, 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 indigenous to
“the soil, climate, and pasturage of the locality on which they
“orazed: 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 conditions of life,—of use or habit—of
natural selection—and of that kind of selection which we have
seen is occasionally 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

1 Quoted by Youatt on Sheep, p. fages, in ‘Bull, Soc. Acclimat.,’ tom.
325, See also Youatt on Cattle, pp. 62, viii., 1861, p. 311

69. 3 «The Poultry Book,’ 186
zs ‘y Book,’ 1866, p. 123.
“MM. Lherbette and De Quatre- + Vana ice, ». 312, p

WOTs Ef, Q

226 SELECTION. Cuap, XXI,.

success. From the facts to be given, it will also be seen that
natural selection would powerfully affect many of our domestic
productions if left unprotected. This is a point of much
interest, for we 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 encounter 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 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,’ “I am
“convinced that better head and beak birds have perished 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, &e. ;
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, accord-
ing 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

° «Treatise on the Almond Tumbler,’ 1851, p. 33.

Cirap, XXI. NATURAL SELECTION. 997

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 naturalist as
unimportant: let us, therefore, see how far it indirectly affects
our domestic productions, and how far 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 pecu-
liarities 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 ascer-
tained that these animals feed on the roots of the Lachnanthes
tenctoria, which colours 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
crispwm abounds there; and this plant does not injure black
sheep, but kills the white ones in about a fortnight’s time.®

Complexion, and liability to certain diseases, are believed.
to run together in man and the lower animals. Thus white
terriers suffer more than terriers of any other colour from the
fatal Distemper.’ In North America plum-trees are liable to
a disease which Downing® believes ig not caused by insects;
the kinds bearing purple fruit are most affected, “and we have
“never known the green or yellow fruited varieties infected

6 Dr. Heusinger, ‘ Wochenschrift fiir
die Heilkunde,’ Berlin, 1846, s, 279.
7 Youatt on the Dog, p, 232.

8 ‘The Fruit-trees of America,’ 1845,
p. 270: for peaches, p. 466,

Q 2

928 SELECTION. . CHap, XXI,

“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 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.
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 certainly more sub-
ject than dark-coloured chickens to the gapes, which 1s caused
by a parasitic worm in the trachea.? On the other hand,
experience has shown that in 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."* White verbenas are especially
liable to mildew.% Near Malaga, during an early period of the
vine-disease, the green sorts suffered most ; “and red and black
grapes, even when interwoven with the sick plants, suffered not
at all.”. In France whole groups of varieties were compara-
tively 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.* 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 12¢ Gardener’s Chronicle,’ 1851, p.599.

Sciences of Mauritius,’ 1852, p. exxxv. 13 * Journal of Horticulture, 1862, p.
10 ¢ Gardener’s Chronicle, 1856,p.379. 476.
11 Quatrefages, ‘Maladies Actuelles 14 ¢Gardener’s Chronicle,’ 1852, pp.

du Ver & Soie,’ 1859, pp. 12, 214. 435, 691.

NATURAL SELECTION. 229

Cuap, XXI.

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 domestication light-
coloured animals suffer most: in Thuringia” 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," was peculiarly
sensitive to the bites of insects. In the West Indies” 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; 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 like-.
wise to depend much on colour; thus, dark pelargoniums suffer
most; and from various accounts it is clear that the cloth-of-gold
variety 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 better, 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 markings of some other kinds.” During one
extremely cold season in Holland all red-flowered hyacinths
were observed to be very inferior in quality. It is believed
by many agriculturists that red wheat is hardier in northern
climates than white wheat.” )

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

5 ¢ Bechstein, ‘ Naturgesch. Deutsch-
lands, 1801, B. i. s. 310.

16 Prichard, ‘Phys. Hist. of Man-
kind,’ 1851, vol. i. p. 224.

7 G. Lewis’s ‘Journal of Residence
in West Indies, ‘Home and (Col.
Library,’ p. 100.

18 Sidney’s edit. of Youatt on the

Pig, p. 24. z

19 * Journal of Horticulture, 18€2, pp.
476, 498; 1865, p. 460. With respect
to the heartsease, ‘Gardener's Chro-
nicle,’ 1863, p. 628.

20 «Des Jacinthes, de leur Culture,’
1768, p. 53: on wheat, ‘Gardener’s
Chronicle,’ 1846, p. 653.

230 SELECTION, CHap, XXI,

is certain that in a flock the white always first fall victims to
the kite.” In Belgium, where so many societies have been esta-
blished for the flight of carrier-pigeons, white is the one colour
which for the same reason is disliked.” On the other hand, it

is said that the sea-eagle (Falco ossifragus, Linn.) on the west, .

coast of Ireland picks out the black fowls, so that “the vil.
lagers avoid as much as possible rearing birds of that colour.”
M. Daudin,” speaking of white rabbits kept in warreng jin
Russia, remarks that their colour is a great disadvantage, ag
they are thus more exposed to attack, and can be seen during
bright nights from a distance. A gentleman in Kent, who failed
to stock his woods with a nearly white and hardy kind of rabbit,
accounted in the same 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 colour being
so much like that of the leaves, or to the fruit always appearing
from a distance unripe,” is not so readily 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.”™
This immunity, though a benefit to the gardener, would be a
disadvantage in a state of nature both to the cherry and
raspberry, as their dissemination depends on birds. I noticed
during 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 (Pyrus aucuparid)
growing in his garden bears berries which, though not differently
coloured, are always devoured 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.

21 'W. B. Tegetmeier, ‘The Field,’ vii., 1860, p. 359.
Feb, 25, 1865. With respect to black 23 «Transact. Hort. Soc.,’ vol. i, 2nd

fowls, see a quotation in Thompson’s series, 1835, p. 275. For raspberries,
‘Nat, Hist. of Ireland,’ 1849, vol. i.p.22. see « Gard. Chronicle,’ 1855, p. 154, and

aD

““ * Bull, dejla Soc, d’Acclimat.,’ tom. 1863, p. 245,

‘Cuap, XXI. NATURAL SELECTION. ISt

Independently of colour, other trifling differences are some-
times 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 pois sans parchemin, are attacked by birds,
much more than common peas. On the other hand, the
purple-podded pea, which has a hard shell, escaped the attacks
of tomtits (Parus major) in my garden far better than any other
kind. The thin-shelled walnut likewise suffers greatly from
the tomtit.> 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.”

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.” 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 uncom-
promising foe of all smooth stone-fruits;” and the cultivator
“has the frequent mortification 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.** 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 extensive
orchard.** 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 importance, for they are
present or absent in closely-related sub-varieties, descended from
the same parent-tree; yet there is good evidence® that the

74 “Gardener’s Chronicle,’ 1843, p. America,’ pp. 266, 501: in regard to

806. the cherry, p. 198.
25 [bid., 1850, p. 732. 29 «Gardener’s Chronicle,’ 1849, p.
6 Thid., 1860, p. 956. 755.
*7 J, De Jonghe, in ‘ Gard. Chronicle,’ 30 «Journal of Horticulture, Sept.
1860, p. 120. 26th, 1865, p. 254; see other references

*8 Downing, ‘Fruit-trees of North given in chap. x.

232 SELECTION, Cap. XXI..

absence of glands leads to mildew, which is highly injurious to
these trees. |

A difference either in flavour or in the amount of nutriment
in cértain varieties causes them to be more eagerly attacked by
various enemies than other varieties of the same species. Bull-
finches (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® of the apple and thorn (Cratezgus
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 plum® had to be care-
fully protected, as they were usually stripped of all their buds
during the winter, whilst other sorts growing near them escaped,
The root (or enlarged stem) of Laing’s Swedish turnip is pre-
ferred by hares, and therefore suffers more than other varieties, -
Hares and rabbits eat down common rye before St. John’s-
day-rye, when both grow together.* 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 ;”** so we see the use of the bitter principle in almonds.

Other slight differences, which would be thought quite unim-
portant, 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 varieties, and, as the flowers
are thus left unprotected, the fruit often fails. In one variety
of the cherry, according to Mr. Rivers,® 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 remark-
| ably unequal in height; and a competent observer believes

that this variety is highly productive, partly because the ears, !
from being distributed at various heights above the ground,

31 Mr. Selby, in ‘Mag. of Zoology 33 Mr. Pusey, in ‘Journal of R.
and Botany,’ Edinburgh, vol. ii, 1838, Agricult. Soc.,’ vol. vi. p.° 179. + For

p- 393. Swedish turnips, see ‘Gard. Chron.,”
2 The Reine Claude de Bavay, 1847, p. 91.
‘Journal of Horticulture, Dec. 27, *! Godron, ‘ De l'Espvce,’ tom. ii. p. 98.

}
1864, p. 511. - 85 *Gardener’s Chron.,’ 1866, p. 732.
iy

Cuar, XXIL FAVOURABLE CIRCUMSTANCES. 238

are less crowded together. The same observer maintains that
in the upright varieties the divergent awns are serviceable by
breaking the shocks when the ears are dashed together by the
wind.* If several varieties of a plant are grown together, and
the seed is indiscriminately harvested, it is clear that the
hardier and more productive kinds will, by a sort of natural
selection, gradually prevail over the others; this takes place, as
Colonel Le Couteur believes,” in our wheat-fields, for, as for-
merly shown, no variety is quite uniform in character. The
same thing, as I am assured by nurserymen, 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 inva-
riably perish, from being of smaller size and not getting their
fair share of food.**

Facts in sufficient number have now been given showing 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:
depending on conditions, about which we are profoundly ignorant.

Circumstances favourable to Selection by Man.

The possibility of selection rests on variability, and this, as
we shall see in the following chapters, mainly depends 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 production of distinct races through careful and pro-
longed selection. We see what selection, though acting on mere
individual differences, can effect when families of cattle, sheep,

36“ Gardener’s Chronicle,’ 1862, pp. 820, 821.

37 ‘On the Varieties of Wheat,’ p. 59.
38 Mr. Hewitt and others, in ‘ Journal of Hort.,’ 1862, p. 773.

‘234 SELECTION, Cuap, XXI,

pigeons, &c., of the same race, have been separately 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 differ-
ence between hounds bred for hunting in different districts

and in many other such cases.

In order that selection should produce any result, it ig
manifest that the crossing of distinct races must be prevented ;
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.”
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 inhos-
pitable land, such as the Falkland islands, where even the

_ light horses of La Plata rapidly decrease in size. Nor could

the wool of sheep have been much increased in length within
the Tropics; yet selection has kept Merino sheep nearly true
under diversified 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 characters, 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, however, 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 ereyhound could
not have been improved up to their present high standard of
excellence without constant training.

As conspicuous deviations of structure occur rarely, the
improvement of each breed is generally the result, as already

39 ¢ Eneyclop. of Rural Sports,’ p. 405,
*° Col. Le Couteur, ‘ Journal Roy. Agricult, Soe.,’ vol. iv. p. 43.

Cuap, XXI. FAVOURABLE CIRCUMSTANCES. 235

remarked, of the selection of slight individual differences.
Hence the closest attention, the sharpest powers 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 individuals 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 conditions of
life should favour the propagation of the species. 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 garden-
ers almost always beating amateurs in the exhibition of new
varieties. In 1845 it was estimated“ that between 4000 and
5000 pelargoniums were annually raised from seed in Eng-
land, yet a decidedly improved variety is rarely obtained.
At Messrs. Carter’s grounds, in Essex, where such flowers as
the Lobelia, 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.* At
Kew, as Mr. Beaton remarks, where many seedlings of common
plants are raised, “ you see new forms of Laburnums, Spireas,
and other shrubs.” So with animals: Marshall,“ in speaking
of the sheep in one part of Yorkshire, remarks, “as they belong
to poor people, 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 remarks, “ was the secret
of his success; and the same will be found in exhibiting fowls,
—successful competitors breed largely, and keep the best.”

It follows from this that the capacity of breeding at an early
age and at short successive intervals, as with pigeons, rabbits,
&c., facilitates selection ; for the result is thus soon made visible,
and perseverance in the work is encouraged. It can hardly be

41 “Gardener’s Chronicle, 1845, p., 43 ‘ Cottage Gardener,’ 1860, p. 368.
273. 44 ¢A Review of Reports,’ 1808, p.
#2 ¢ Journal of Horticulture, 1862, p. 406,
A572 45 ¢Gardener’s Chronicle,’ 1853, p. 45.

256 SELECTION, _ Cap, XXI.

accidental that the great majority of the culinary and agricul.
tural 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 Jeru-
salem 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 varieties. No doubt fruit-treesg,
which cannot be propagated quickly by seed, have yielded a
host of varieties, though not permanent races ; but-these, judging
from pre-historic remains, were produced at a later and more
civilised epoch than the races of culinary and agricultural plants.

A species may be highly variable, but distinct races wil] 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 ;“° 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 cultivated by the aboriginal
Mexicans, has yielded races; and it would be impossible to
match the queen-bee with any particular drone, and most difficult
to match cochineal 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 remarked, yield dis-
tinct 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 ; consequently there has been no selection,
and distinct races have not been formed, We must not attribute
the inferiority 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 Cordova, as I am in-
formed (Feb. 1860) by Mr. W. E. Webb, C.E., they are care-
fully bred, as much as 2002, having been paid for a stallion ass,

*6 Isidore Geoffroy St. Hilaire, ‘Hist, Nat. Gen.,’ tom. iii, p. 49. On the
Cochineal Insect, p. 46.

Cuap, XXI. FAVOURABLE CIRCUMSTANCES. OST

and they have been immensely improved. In Kentucky, asses
haye been imported (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.” .

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 distinct races. The common
mignonette (Reseda odorata), from bearing inconspicuous flowers;
valued solely for their fragrance, “remains in the same unim-
“proved condition as when first introduced.” Our common
forest-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,” 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 culti-
vated year after year mingled with our corn crops, have not pro-
duced distinct races; but this is accounted for by slight varia-
tions not having been selected 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.

‘7 Capt. Marryat, quoted by Blyth Archipelago,’ vol. ii., 1848, p. 645.
in ‘Journ. Asiatic Soc. of Bengal,’ vol, 49 Mr. Abbey, in ‘ Journal of Horti-
XXviil, p. 229, culture, Dec. 1, 1863, p. 430.

48 Mr. Oxley, ‘ Journal of the Indian °° *On Naval Timber,’ 183], p. 107.

238 SELECTION, Cap, XXI..

The importance of selection is likewise shown by considering
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 pre-
vails. Rose-combs, double-combs, cup-combs, &c., and colourg
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 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.

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 im-
provement is eagerly sought and selected. Thus with short-faced
tumbler-pigeons, the shortness of the beak, shape of head and
plumage,—with carriers, the length of the beak and wattle,—
with fantails, the tail and carriage,—with Spanish fowls, the white
face 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 diffi-
culty of breeding them up to the highest standard of excellence.
This subject has been discussed by fanciers,” and the greater
prizes given for highly improved breeds, in comparison with
those given for old breeds which are not now undergoing rapid
improvement, has been fully justified. Nathusius makes” a
similar remark when discussing the less uniform character of
improved Shorthorn cattle and of the English horse, in com-
parison, for example, with the unennobled cattle of Hungary,
or with the horses of the Asiatic steppes. This want of uni-
formity 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

51 Mr. Baily, in ‘The Poultry Chro- cember, p. 171; 1856, January, Pp-
nicle,’ vol. ii., 1854, p. 150. Alsovol.i, 248, 323. 2
p. 342; vol. iii, p. 249. 53 ‘Ueber Shorthorn Rindvieh,’ 1897,

52 “Cottage Gardener,’ 1855, De- s. 51.

= Sancumneseneine

Cuap, XXI. CARRIED TO AN EXTREME, 939

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
beyond an early standard of excellence, and we know that 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 neglected or not sub-
jected to incessant selection, soon degenerate. Youatt gives a
curious instance of this in some cattle formerly kept in Glamor-
ganshire; but in this case the cattle were not fed with sufficient
care. Mr. Baker, in his memoir on the Horse, sums Hp Tt
“must have been observed in the preceding pages that, when-
“ever there has been neglect, the breed has proportionally dete-
“riorated.” If a considerable number of improved 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 score or hundred gene-
rations they would be very far from excellent of their kind; but,
from what we see 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 long-continued inheritance. But I have
attempted to show in the fourteenth chapter that this belief
apparently resolves itself into the following proposition, namely,
that all characters whatever, whether recently acquired or an-
cient, tend to be transmitted, but that those which have already
long withstood all counteracting influences, will, as a general

rule, continue to withstand them, and consequently be faithfully
transmitted.

Tendency in Man to carry the practice of Selection to an extreme
point.

Tt is an important principle that in the process of selection
man almost invariably wishes to go to an extreme point. Thus,
in usual qualities, there is no limit to his desire to breed certain

4 ‘The Veterinary,’ vol. xiii,
on Cattle, p. 51._

Pp. 720, For the Glamorganshire cattle, see Youatt

240 SELECTION,

horses and dogs as fleet as possible, 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 dregs,

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 compara-
tively 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.” J*erguson, speaking
of fowls, says, “their peculiarities, whatever 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, in discussing the merits of the sub-varieties of the
Belgian canary-bird, remarks, “ Fanciers always go to extremes;
“they do not admire indefinite properties.” ®

This principle, which necessarily leads to divergence of
character, explains the present state of various domestic races.
We can thus see how it is that race-horses and dray-horses,
ereyhounds and mastiffs, which are opposed to each other in
every character,—how varieties so distinct as Cochin-china fowls
and bantams, or carrier-pigeons with very long beaks, and
tumblers with excessively 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 exist-
ing 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 extinction of the intermediate and
less-valued forms, is the key which unlocks the mystery how
man has produced such wonderful results.

65 J. M, Haton, ‘A Treatise on Fancy Pigeons,’ p. 82; Ferguson, on ‘ Rare and
Prize Poultry, p. 162; Mr. Brent, in ‘ Cottage Gardener,’ Oct. 1860, p. 19.

Cuap, XXI. CARRIED TO AN EXTREME. 241

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,°®
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.” 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 con-
tinuing to vary in the same direction. The tendency to mere
general variability or plasticity of organisation can certainly be
inherited, even from one parent, as has been shown by Gartner
and Kélreuter, in the production 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, 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 fasti-
gate or upright Irish yew is described as differing greatly from
the parent-form “by the exaggeration of the fastigate habit of
its branches.” °* 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.” A great rose-grower, Mr. Rivers, has made the
same remark with respect to roses. Sageret,°? 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 ig apparently much truth in this

56 «Die Racen des Schweines,’ 1860, 58 Verlot, ‘Des Varictés, 1865, p. 94.
8. 48. °° Mr. Patrick Sheriff, in ‘Gard,
57 See some good remarks on this Chronicle,’ 1858, jt Mea SB
head by M. de Quatrefages, ‘Unité de 69 *Pomologie Physiolog.,” 1830, De
l’Espece Humaine,’ 1861, p. 119, 106.

VOL. g Be R

242 SELECTION, Cup, XX],

remark ; for we can in no other way understand the surprising
amount of difference between varieties in the parts or qualities
which are valued, whilst other parts retain nearly their original
character.

The foregoing discussion naturally leads to the question, what
is the limit to the possible amount of variation in any part
or quality, and, consequently, is there any limit to what selec.
tion can effect? Will a race-horse ever be reared fleeter than
Eclipse? Can our prize-cattle and, sheep be still further im-
proved? Will a gooseberry ever weigh more than that pro-
duced 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; but
it is certain that we ought to be cautious in answering 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 constitution." 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
who 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 qualified 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. or instance, the short-faced tumbler-pigeon has
been greatly modified; nevertheless, according to Mr. Eaton,”
“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

$1 Youatt on Sheep, p. 521. 2 «A Treatise on the Almond Tumbler,’ p. i.

Cuap. XXI. SELECTION. 243

perfection had been attained with our flowers, but a higher
standard has soon been reached. Hardly any fruit has been more
improved than the strawberry, yet a great authority remarks,**
“it must not be concealed that we are far from the extreme
limits at which we may arrive.”

Time is an important element in the formation of our domestic
races, as it permits innumerable individuals to be born, and these
when exposed to diversified conditions are rendered variable.
Methodical selection has been occasionally practised from an
ancient period to the present day, even by semi-civilised people,
and during former times will have produced some effect. Uncon-
scious selection 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 domes-
ticated animals and cultivated plants, we begin dimly to see.
When the lake-buildings of Switzerland were inhabited during
the Neolithic period, several animals were already domes-
ticated and various plants cultivated. 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—possessed
at least some few domesticated animals, although their remains
have not as yet been discovered, Tf 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 Sclayonic languages had not as yet
diverged from their common parent-tongue.*4

°° M. J. de Jonghe, in ‘Gard. Chron.,’ 1858, p. 173.
6 Max Miiller, ‘Science of Language,’ 1861, p. 223.

ng

244 SELECTION. CHAP, XXI,

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,®° of the history of the
great majority of our breeds, even of our more modern breeds,
agrees with the view that their production, through the action
of unconscious and. methodical selection, has been almost insen-
sibly 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, becomes 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 some-
what distinct character, its history, hardly noticed at the time,
will have been completely forgotten; for, as Low remarks,"
“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.*7 As each new variety is
produced, the earlier, intermediate, and less valuable forms will
be neglected, 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 destruc-
tion or from close interbreeding ; and this is an event which, in
the case of well-marked breeds, excites attention. The birth or
production of a new domestic race is so slow a process that it

65 Youatt on Cattle, pp. 116, 128. 66 ‘Domesticated Animals,’ p. 188.
7 Volz, ‘ Beitrige zur Kulturgeschichte, 1852, s. 99 et passim.

eo

Cuap, XXI. SELECTION, 245

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 between arti-
ficial and natural races. The latter are more uniform in cha-
racter, 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 modi-
fied by natural selection, and only to a small extent by man’s
unconscious and methodical 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,”®* turnspit dogs, ancon
sheep, niata oxen, Polish fowls, fantail-pigeons, &¢. ; their charac-
teristic 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 generally
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 disturbing 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 strugele throughout its life with many com-
petitors 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

°* Blaine, ‘ Encyclop. of Rural Sports,’ p. 213,

246 SELECTION, CHAP. XXI,

functions and mutual relations of parts—will be rigorously tested,
preserved, or rejected. Natural selection often checks man’s
comparatively feeble and capricious attempts 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 naturalists 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 with finer or longer wool and with better carcases,
or handsomer fowls, or carrier-pigeons with beaks just percep-
tibly longer to the practised eye, and thus be successful at an
exhibition. Thus far he will go, but no farther. He does not
reflect on what follows from adding up during a long course of
time many, slight, successive modifications ; 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 systematic
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 gradations, 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

—

Cuap, ¥Xi; SELECTION. 247

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 circum-
stances have slowly changed, which many animals have under-
gone in the same country, or when transported into a foreign land.
We see the combined effects of methodical and unconscious selec-
tion in the great amount of difference between varieties in those
parts or qualities 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 struggle for existence, and there-
fore 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 varia-
bility; and this is mainly caused, as we shall hereafter see, by
changes in the conditions of life. Selection is sometimes ren-
dered 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-continued close interbreeding. That methodical selec-
tion may be successful, the closest attention and discernment,
combined with unwearied patience, are absolutely necessary ;
and these same qualities, though not indispensable, are highly
serviceable in the case of unconscious selection. It is almost
necessary that a large number of individuals 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 degree inferior may be freely rejected. Hence length
of time is an important element of success. Thus, also, propa-
gation 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

248 SELECTION. Cuap, XXI.

4

wherever selection is not practised, distinct races are not formed.
When any one part of the body or quality is not attended
to, it remains either unchanged 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 parts or
organs which are now undergoing rapid improvement 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 selection, 3

whether methodical or unconscious, of all useful and pleasing
qualities. This is an important principle, as it leads to con-
tinued 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 varied; and that this
occurs, is proved by the steady and gradual improvement of

many animals and plants during lengthened periods. The prin-

ciple of divergence of character, combined with the neglect and
final extinction of all previous, less-valued, and intermediate
varieties, explains the amount of difference and the distinct-
ness of our several races. Although we may have reached the
utmost limit to which certain characters 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 between 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 absolutely

depends on what we in our ignorance call spontaneous or acci- —

dental 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 determined by the force of gravity, the nature

es

Cuap, XXI. SELECTION, 249

of the rock, and the slope of the precipice,—events and circum-
stances, all of which depend on natural laws; but there is no
relation between these laws and the purpose for which each
fragment is used by the builder. In the same manner the
variations of each creature are determined by fixed and im-
mutable laws; but these bear no relation to the living struc-
ture 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 selection, whether applied by man or by
nature; for though variability is indispensably necessary, yet,
when we look at some highly complex and excellently adapted
organism, 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 supposed architect is
unimportant in comparison with his skill.

250 CAUSES OF VARIABILITY. CHAP. XXII,

CHAPTER XXII.

CAUSES OF VARIABILITY.

VARIABILITY DOES NOT NECESSARILY ACCOMPANY REPRODUCTION — CAUSES ASSIGNED
BY VARIOUS AUTHORS — INDIVIDUAL DIFFERENCES — VARIABILITY OF EVERY KIND
DUE TO CHANGED CONDITIONS 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 CONDITIONS — CLOSE INTERBREEDING AND THE IMAGINATION OF THE
MOTHER SUPPOSED TO CAUSE VARIABILITY — CROSSING AS A CAUSE OF THE APPEAR-
ANCE 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 productions.
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 contingent on reproduction,
and as much an aboriginal law, as growth or inheritance.
Others have of late encouraged, perhaps unintentionally, this
view by speaking of inheritance and variability as equal and
antagonistic principles. Pallas maintained, and he has had
some followers, that variability depends exclusively on the
crossing of primordially distinct forms. Other authors attri-
bute the tendency to variability to an excess of food, and with
animals to an excess relatively to the amount of exercise
taken, or again to the effects of a more genial climate. That
these causes are all effective is highly probable. But we must,
I think, take a broader view, and conclude that organic beings,
when subjected during several generations to any change what-
ever 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 being, than on the nature of the changed
conditions.

Cuap. XXII. CAUSES OF VARIABILITY. VATS |

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 Lap-
lander by long practice knows and gives a name to each
reindeer, though, as Linneus 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 acquired. Verlot mentions a
gardener who could distinguish 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, was 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 absolutely undistinguishable,
yet really differ.!

As Linnzus has compared the reindeer in number to ants, I
may add that each ant knows its fellow of the 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 re-
cognises, independently of odour, its fellow; and if all the ants
of the same community have not some countersign or watch-

word, they must present to each other’s senses some distin-
tinguishable character.

1 «Des Jacinthes, &c., Amsterdam, lated by Sir J. E. Smith, vol. i. p. 314.
1768, p. 43; Verlot, ‘Des Variétés, The statement in regard to German
&e., p. 86. On the reindeer, see shepherds is given on the authority of
Linneus, ‘Tour in Lapland,’ trans- Dr. Weinland.

252 CAUSES OF VARIABILITY.

CHAP. XXII,

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 characters of the two parents,
and by the more or less complete recovery through reversion
of ancestral characters on either side; but we thus only push
the difficulty further back in time, for what made the parents
or their progenitors different? Hence the belief? that an
Innate tendency to vary exists, independently of external con.
ditions, seems at first sight probable. But even the seeds
nurtured in the same capsule are not subjected to absolutely
uniform conditions, as they draw their nourishment from dit-
ferent points; and we 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 comparison with human twins,
which often resemble each other in external appearance, mental
disposition, and constitution, in so extraordinary a manner,
apparently proves that the state of the parents at the exact
period of conception, or the nature of the subsequent embryonic
development, has a direct and powerful influence. on the cha-
racter of the offspring. Nevertheless, when we reflect on the

2 Miiller’s ‘ Physiology,’ Eng. trans-
lation, vol. ii. p. 1662. With respect
to the similarity of twins in consti-
tution, Dr. William Ogle has given me
the following extract from Professor
Trousseau’s Lectures (‘Clinique Médi-
cale, tom. i. p. 523), in which a curious
case is recorded :—*J’ai donné mes

. Soins & deux fréres jumeaux, tous deux
si extraordinairement ressemblants qu'il
m’était impossible de les reconnaitre,
a moins de les voir l'un & cdté de
autre. Cette ressemblance physique
s’étendait plus loin: ils avaient, per-
mettez-moi l’expression, une similitude
pathologique plus remarquable encore,
Ainsi ’un d’eux que je voyais aux néo-
thermes & Paris malade d’une oph-
thalmie rhumatismale me disait, ‘En
ce moment mon fréere doit avoir une
ophthalmie comme la mienne;’ et
comme je m’étais récrié, il me montrait
quelques jours apres une lettre qu’il

venait de recevoir de ce frére alors &
Vienne, et qui lui écrivait en effet—
‘J’ai mon ophthalmie, tu dois avoir la
tienne.’” Quelque singulier que ceci
puisse paraitre, le fait n’en est pas moins
exact : on ne me |’a pas raconté, je ’ai vu,
et jen ai vu d’autres analogues dans
ma pratique. Ces deux jumeaux étaient
aussi tous deux asthmatiques, et asth-
matiques & un effroyable degré. Ori-
ginaires de Marseille, ils n’ont jamais
pu demeurer dans cette ville, ow leurs
intéréts les appelaient souvent, sans
€tre pris de leurs accés; jamais ils n’en
éprouvaient 2 Paris. Bien mieux, il
leur suffisait de gagner Toulon pour
étre guéris de leurs attaques de Mar-
seille. Voyageant sans cesse et dans
tous pays pour leurs affaires, ils avaient
remarqué que certaines localités leur
étaient funestes, que dans d’autres ils
étaient exempts de tout plénomene
oppression,”

Cuap, XXII. CAUSES OF VARIABILITY. 253

individual differences between organic beings in a state of
nature, as shown by every wild animal knowing 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 repro-
duction.

Those authors who adopt this latter view would probably
deny that each separate variation has its own proper exciting
cause. Although we can seldom trace the precise relation
between cause and effect, yet the considerations presently to
be given lead to the conclusion that each modification must
have its own distinct cause. When we hear of an infant
born, for instance, with a crooked finger, a misplaced tooth,
or other slight deviation of structure, it is difficult to bring
the conviction home to the mind that such abnormal cases
are the result of fixed laws, and not of what we blindly call
accident. 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 little fingers
on both hands crooked; and in both children 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
deviations of structure, the idea of accident is at once excluded ;
and we are compelled to admit that there must haye existed
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 favour of the view that variations

of all kinds and degrees are directly or indirectly caused by the
conditions of life to which each being,

ancestors, have been exposed,
No one doubts that domesticated productions are more variable
than organic beings which have neyer been removed from their

and more especially its

254 CAUSES OF VARIABILITY. Cuap. XXII,

natural conditions. Monstrosities graduate so insensibly into
mere variations that it is impossible 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 notice-
able in the natural as in the cultivated state. Under nature,
the individuals of the same species are exposed to nearly
uniform conditions, for they are rigorously kept to their proper
places by a host of competing animals and plants; they haye,
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 liable to a certain amount of variation. The cir-
cumstances under which our domestic productions are reared
are widely different: they are protected from competition; they
have not only been removed from their natural conditions 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 domesticated productions, with the rarest excep-
tions, vary far more than natural species. The hive-bee, which
feeds itself 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 (Secale cereale) has afforded fewer and less marked varieties
than almost any other cultivated plant ;* 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 independent of seminal
reproduction,. and likewise of reversion to long-lost ancestral
characters. No one will maintain that the sudden appearance

3 Isid. Geoffroy St. Hilaire, ‘Hist. des Anomalies,’ tom. iii. p. 352; Moquin=

‘Tandon, ‘ Tératologie Végétale,’ 1841, p. 115.
4 Metzger, ‘Die Getreidearten,’ 1841, s. 39.

Cuap. XXII. CAUSES OF VARIABILITY. 255

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 argument 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
concern us, as they occur far more frequently on plants which
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 gentleman’s pleasure-grounds; and
occasionally there may be seen, on beach 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 pro-
tected in nursery-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 occurred with many of our highly culti-
vated 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 Natwre 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 ag it ig possible to conceive, organic
beings of all kinds, when domesticated or cultivated, have varied,

256 CAUSES OF VARIABILITY.

CPAP, XXII,

We see this with the many domestic races of quadrupeds and
birds belonging to different orders, with gold-fish and silk-worms,
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 banana, 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 silkworm; and in China sixty-three
varieties of the bamboo are used for various domestic purposes.®
These facts alone, and innumerable others could be added, in-
dicate that a change of almost any kind in the conditions of life
suffices to cause variability—different changes acting on diffe-
rent organisms.

Andrew Knight® attributed the variation of both animals and
plants to a more abundant supply of nourishment, 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 protection of a wall, have varied much in
England, as has the orange-tree in northern Italy, where it is
barely able to exist.’ Nor can we overlook the fact, though not
immediately connected with our present subject, that the plants
and shells of the arctic regions are eminently variable.® More-
over, it does not appear that a change of climate, whether more
or less genial, is one of the most potent causes of variability ;
for in regard to plants Alph. De Candolle, in his ‘Géographie

5 On the date-palm, see Vogel,
‘Annals and Mag. of Nat. Hist.,’
1854, p. 460. On Indian varieties,
Dr. F. Hamilton, ‘ Transact. Linn. Soc.,’
vol. xiv. p. 296. On the varieties cul-
tivated in Tahiti, see Dr. Bennett, in
Loudon’s ‘Mag. of N. Hist.,’ vol. v.,
1832, p. 484. Also Ellis, ‘Polynesian
Researches,’ vol. i. pp. 375, 370. On
twenty varieties of the Pandanus and
other trees in the Marianne Island, see
‘Hooker’s Miscellany,’ vol. i. p. 308,
On the bamboo in China, see Huc’s

‘ Chinese Empire,’ vol. ii. p. 307.

6 «Treatise on the Culture of the
Apple,’ &c., p. 3.

7 Gallesio, ‘Teoria della Ripro-
duzione Veg.,’ p. 125.

8 See Dr. Hooker's Memoir on Arctic
Plants in ‘Linn. Transact.,’ vol. xxiii.
part ii) Mr. Woodward, and a higher
authority cannot be quoted, speaks of
the Arctic mollusca (in his ‘Rudimentary
Treatise, 1856, p. 355) as remarkably
subject to variation.

a.

kK

Cuap, XXII. CAUSES OF VARIABILITY. 957

Botanique, repeatedly shows that the native country ofa 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 domesticated 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.°

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.” In order to give a plant more
food it suffices in most cases to grow it separately, and thus pre-
vent other plants robbing its roots. It is surprising, as I have
often seen, how vigorously our common wild plants flourish when
planted by themselves, though not in highly manured land.
Growing plants separately is, in fact, the first step in culti-
vation. We see the converse of the belief that excess of food
induces variability in the following statement by a great raiser
of seeds of all kinds." “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 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,

9 Bechstein, in his ‘ Naturgeschichte lated by Henfrey, 1848, p. 169. See
der Stubenvogel, 1840, 8.238, has some also Alex. Braun, in ‘ Bot. Memoirs,’
good remarks on this subject. He states Ray. Soc., 1853, p. 313

. 9 C 9 Vee vw.

that his canary-birds varied in colour, 1 Messrs. Hardy and Son, of Maldon
though kept on uniform food, in “Gard aS ; é
. Ch le,’ 1856, p. 458.
+The Plant,’ by Schleiden, trans- a ate ;
VOL. II. g

258 CAUSES OF VARIABILITY. CHAP. XXII.

they will be in excess; and as growth, nutrition, and reproduc-
tion are intimately allied processes, this superfluity might dis-
turb the due and proper action of the reproductive organs, 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 well fed for many genera-
tions, 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 thought 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 received
nutriment in excess, all have been exposed to changes of
various kinds. J ruit-trees are grafted on different stocks,
and grown in various soils. The seeds of culinary and agri-
cultural 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 varia-
bility. The simple fact of almost all our cultivated 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 (Crategus oxycantha) has pro-
duced; yet this tree has been subjected to hardly any culti-
vation. In Staffordshire I carefully examined a large number
of two British plants, namely, Geranium pheeum and Pyrenaicum,
which have never been highly cultivated. 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

Cap, XXII, CAUSES OF VARIABILITY. 259

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 sur-
prise,” that, whilst the feral horses on the Pampas are always of
one of three colours, and the cattle always of a uniform colour,
yet these animals, when bred on the unenclosed estancias, though
kept ina state which can hardly be called domesticated, and
apparently exposed 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.

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 seeds yield more varieties
than do the seeds of the same variety of pear when grafted on
the wild pear.’* But as the pear and quince are distinct species,
though so closely related that the one can be readily grafted
and sueceeds 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,” “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 variety, grafted on another
May-leafing variety, though both stock and graft have the same
eatly habit of leafing, yet the seedlings leaf at various times,

2 «Quadrupedes du Paraguay,’ 1801, M4 Quoted by Sageret, ‘Pom, Phys.,’
tom. ii. p. 319. 1830, p. 43.

8 M‘Clelland on Indian Cyprinide, 1 <The Fruits of America,’ 1845,

‘Asiatic Researches,’ vol. xix. part ii., — p. 5.
1839, pp. 266, 268, 313.

p 2

260 CAUSES OF VARIABILITY. Cuap, XXII.

even as late as the 5th of June.’ 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 and 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 culti-
vated fruits rarely originate with nurserymen.” In England, on the
other hand, no instance of a good pear having been found wild has been
recorded; and Mr. Rivers informs me that he knows of only one instance
with apples, namely, the Bess Poole, which was discovered in a wood in
Nottinghamshire. 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 froma remark made by a French
gardener,'® who regards it as a national calamity that such a number of
pear-trees are periodically cut down for firewood, before 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 pro-
duction is very doubtful. These varieties, however, are probably all

_ descended ® from old cultivated kinds growing in adjoining orchards,—a
circumstance which will account for their variability; and out of a vast
humber of varying trees there will always be a good chance of the appear-
ance of a valuable kind. In North America, where fruit-trees frequently
spring up in waste places, the Washington pear was found in a hedge,
and the Emperor peach in a wood.”

With respect to wheat, some writers have spoken™ as if it were an ordi-
nary 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 probably receive a sufficient amount

© M. Cardan, in ‘Comptes Rendus,’
Dec. 1848, quoted in ‘ Gard. Chronicle,’
1849, p. 101.

@ M. Alexis Jordan mentions four
excellent pears found in woods in
France, and alludes to others (‘Mém.
Acad. de Lyon,’ tom. ii. 1852, p. 159).
Poiteau’s remark is quoted in‘ Gar-
dener’s Mag.,’ vol. iv., 1828, p. 385.
See ‘Gard. Chronicle,’ 1862, p. 335,
for another case of a new variety of the
pear found in a hedge in France. Also
for another case, see Loudon’s ‘ Ency-
clop. of Gardening,’ p. 901. Mr. Rivers
has given me similar information.

18 Duval, ‘Hist. du Poirier, 1849,
p. 2.

19 T infer that this is the fact from
Van Mons’ statement (‘Arbres Frui-
tiers,’ 1835, tom. i. p. 446) that he finds
in the woods seedlings resembling all
the chief cultivated races of both the
pear and apple. Van Mons, however,
looked at these wild varieties as abo-
riginal species. |

20 Downing, ‘Fruit-trees of North
America,’ p. 422; Foley, in ‘ Transact.

Hort. Soe.,’ vol. vi. p. 412.
21 « Gard. Chronicle, 1847, p. 244.

CuaP. XXII. CAUSES OF VARIABILITY. 261

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.”

Whether our domestic productions would ever become go com-
pletely habituated to the conditions under which they now live,
as to cease varying, we have no sufficient means for judging.
But, in fact, our domestic productions are never exposed for a
great length of time to uniform conditions, and it is certain that
our most anciently cultivated plants, as well as animals, still go
on varying, for all have recently undergone marked improve-
ment. In some few cases, however, plants have become habituated
to new conditions. Thus Metzger, who cultivated in Germany
during many years numerous varieties of wheat, brought from
different countries,” 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 influence of chan ged
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 requisite 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.“ After several 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 (Brachycome
“tberidifolia) kept to its original colour ; it then varied into Lilac
“and purple and other minor shades,” Analogous facts have
been recorded with the Scotch rose. Tn discussing the variability
of plants several experienced horticulturists have spoken to the

22 Gardener’s Chronicle,’ 1841, p. iii. p. 225; Bronn, ‘Geschichte der

383; 1850, p. 700; 1854, p. 650, Natur,’ b. ii. s. 119.
*% ‘Die Getreidearten,’ 1843, s, 66, *° ‘Journal of Horticulture,’ 1861, p.
116, 117.

112 ; on Zinnia, ‘ Gardener's Chronicle,’
24 Sabine, in ‘ Hort. Transact,,’ vol, 1860, p. 852,

262 CAUSES OF VARIABILITY. . CuaP, XXII,

same general effect. Mr. Salter*® 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 varieties of pears and strawberries,” re-
marks with respect to the former, “There is another principle,
“ namely, 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 continually augmenting in the same direc-
tion each modification; for this power depends on continued
variability of the same general kind. The most celebrated hor-
ticulturist in France, namely, Vilmorin,* 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 extremely
remote epoch, we cannot, of course, say whether they varied
quickly or slowly when first subjected to new conditions. But
Dr. Bachman” 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 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,” who has often reared
birds from the eggs of the wild duck, and who took precautions

26 «The Chrysanthemum, its History, &c., 1865, p. 28.

&e.,” 1865, p. 3. 29 ¢Bxamination of the Characteris-
27 «Gardener’s Chron.,’ 1855, p. 54; tics of Generaand Species :’ Charleston,

‘Journal of Horticulture, May 9; 1865, 1855, p. 14.

p. 363. - 20 Mr. Hewitt, ‘Journal of Hort.,
°8 Quoted by Verlot, ‘Des Vari¢iés, 1863, p. 39.

Cuap, XXII. CAUSES OF VARIABILITY. 263

that there should be no crossing with domestic breeds, has
given, as previously stated, full details on the changes which they
eradually 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 white collar round the neck
“of the mallard became much broader and more irregular, and
“ white feathers appeared in the ducklings’ wings.” They in-
creased also in size of body ; their legs became less fine, and they
lost their elegant carriage. Fresh eggs were 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 pro-
duced in the first generation puppies marked with white and
other colours; but these introduced dingos had probably been
procured from the natives, who keep them in a semi-domesticated
state. It is certainly 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 throw a little light on this fact.

Returning now to the causes which are supposed to induce
variability. Some authors® believe that close interbreeding
gives this tendency, and leads to the production 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 fertility 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 car-
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 per-
sons, that the imagination of the mother affects the child in

51 Devay, ‘Mariages Consanguins,’ pp. 97, 125. In conversation I have found
two or three naturalists of the same opinion.

264. CAUSES OF VARIABILITY. CHAP, XXII,

the womb.” This view is evidently not applicable to the lower
animals, which lay unimpregnated eggs, or to plants. Dr. William
Hunter, in the last century, 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 de-
tected between the woman’s answer and any abnormal structure :
but when she knew the nature of the structure, she frequently
suggested some fresh cause. The belief in the power of the
mother’s imagination may perhaps 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—tIn an early part of this
chapter it was stated that Pallas® and a few other naturalists
maintain that variability is wholly due to crossing. If this means
that new characters never spontaneously appear in our domestic
races, but that they are all directly derived from certain aboriginal
species, the doctrine is little less than absurd; for it implies
that animals like Italian greyhounds, pug-dogs, bull-dogs, pouter
and fantail pigeons, &c., were able to exist in a state of nature.
But the doctrine may mean something widely different, 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 various 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 thatthe breeds of various animals, such as
of the rabbit, pigeon, duck, &c., and the varieties of several plants,
are the modified descendants of a single wild species. Neverthe-
less, 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

* Miiller has conclusively argued p. 1405.
against this belief, ‘Elements of 33 “Act. Acad. St. Petersburg,’ 1780,
Phys.,’ Eng. translat., vol. ii, 1842, part ii. p. 84, &e.

Cuap, XXII. CAUSES OF VARIABILITY. 265

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 impossible
to distinguish between the reappearance of ancient characters
and the first appearance of new characters. Practically, whether
new or old, they would be new to the breed in which they
reappeared.

Gartner declares,* 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 character; but that from the
odd manner in which the characters derived from the parents were com-
bined, 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 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.®

Prof. Lecoq** 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 Species of the genus, from M.
julapa. Herbert, also, has described *7 the offspring from a hybrid Rho-
dodendron as being “as wnilike 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 appearance of quite new characters ig probable. M.
Carriére® has lately discussed this subject: he states that Lrythrina cris-
tagalli had been multiplied by seed for many years, but had not yielded
any varieties: it was then crossed with the allied £. herbacea, 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

34 < Bastarderzeugung,’ s. 249, 255, 36 “De la Fécondation, 1862, p. 311.
995. 7 * Amaryllidaces,’ 1837, p. 362.

35 ‘Nova Acta, St. Petersburg,’ 1794, ° Abstracted in ‘ Gard. Chronicle
p. 378 ; 1795, pp. 307, 313, 316; 1787, 1860, p. 1081.
p. 407.

(Jt)

266 CAUSES OF VARIABILITY. Cuap, XXII.

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 ® that, when a genus includes 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 nume-
rous 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. 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 species 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 characters and the reappearance of long-lost
characters, evoked through the act of crossing. I will give an instance of
the difficulty in distinguishing 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” crossed
Datura levis and ferox, both 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 resembled 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. ferox,
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.

39 This was the opinion of the elder 1837, p. 37, has discussed this same
De Candolle, as quoted in ‘ Dic. Class. point.
@Hist. Nat.,’ tom. viii. p. 405. Puvis, 40 “Comptes Rendus,’ Novembre oh
in his work, ‘De la Dégénération,’ 1864, p. 838,

CuHap, XXII. CAUSES OF VARIABILITY. 267

the first generation are generally uniform, but subsequently they display
an almost infinite diversity of character. He who wishes, says Kolreuter,"
to obtain an endless number of varieties from hybrids should cross and
recross them. There is also much variability when hybrids or mongrels
are reduced or 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 Girtner,” on whose authority the foregoing statements are made,
never succeeded in effecting a union; but Max Wichura*® united six dis-
tinct species of willows into a single hybrid. ‘The sex of the parent-species
affects in an inexplicable manner the degree of variability of hybrids;
for Girtner “4 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 barbatus crossed by the hybrid
D. chinensi-barbatus were more variable than those raised from this latter
hybrid fertilised by the pure D. barbatus. Max-Wichura “ insists strongly
on an analogous result with his hybrid willows. Again Girtner ** asserts
that the degree of variability sometimes differs in hybrids raised from re-
ciprocal 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 charac-
ters, the variability of successive crossed generations 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 these same characters 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 whole organi-
sation or certain organs, This direct action of changed con-
ditions perhaps comes into play much more frequently than can
be proved, and it is at least clear that in all cases of bud-

* ‘Nova Acta, St. Petersburg” 1794, 1865, , 24.

pb. 391.
7 - a bed "s.5 44 ¢ Bastarderzeugung,’ s. 452, 507.
2 « Bastarderzeugung, ’s. x , :
43 ¢ e ye t ee Weteneg en: 4 «Die Bastardbefruchtung,’ s. 56.
ie Bastardbefruchtung’ &e :
: SHO TING 4/00 46 ‘Bastarderzeugung,’ 8. 423.

268 CAUSES OF VARIABILITY. CaP. XXII.

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 in-
stance, carnivorous birds more readily than carnivorous mammals, 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.

Kolreuter *’ was struck with the parallelism between the excessive
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 Wichura* has
gone one step farther, and shows that with many of our highly cultivated
plants, such as the hyacinth, tulip, auricula, snapdragon, potato, cabbage,

as the banana, pine-apple, breadfruit, and others previously mentioned,
have their reproductive organs so seriously affected as to be generally
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 and a tendency to variability; but we
must not conclude that 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 considerations it would
seem that changes in the conditions of life lead either to sterility or to varia-
bility, 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.

47 ‘ Dritte Fortsetzung,’ &c.,1766,s. 85 Berkeley on the same _ subject, in
o* ie Bastardbefruchtung, &c., ‘Journal of Royal Hort. Soc., 1866
1865, s, 92: see also the Rev. M. J. p. 80.

is NLC
Cuap. XXII. CAUSES OF VARIABILITY. 269

The period of life at which the causes that induce variability act, is
another obscure subject, which has been discussed by various author 8. io
some of the cases, to be given in the following chapter, 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 variations, are often caused by the embryo being injured whilst
in the mother’s womb or in the egg. Thus I. Geoffroy St. Hilaire °° 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 monstrosities 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 subse-
quently developed; and this would be less likely to occur with parts
injured at a later period.*! When any part or organ becomes monstrous
through abortion, a rudiment is generally left, and this likewise indicates
that its development had already commenced.

Insects sometimes have their antennz or legs in a monstrous condition,
and yet the larve from which they are metamorphosed do not possess
either antenne or legs; and in these cases, as Quatrefages ® believes, we
are enabled to see the precise period at which the normal progress of deve-
lopment has been troubled. But the nature of the food given to a caterpillar
sometimes affects the colours 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 larve. There is
no reason to suppose that organs which have been rendered monstrous
have always been acted on during their development; the cause may have
acted on the organisation at a much earlier stage. Itis 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 de-
veloped 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 sterility 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
occurrence of bud-variations ; for a bud Seems to be the analogue of an ovule.
But the male element is apparently much oftener affected by changed con-

49 Dr. P. Lucas has given a history °l Idem, tom. iii. pp. 392, 502.

of opinion on this subjeet : ‘Héréd. Nat. *2 See his interesting work, ‘Méta-
1847, tom. i. p. 175. morphoses de Homme,’ &c., 1862, p.

°° «Hist.des Anomalies,’ tom. iii. Pp: 499,--5 129;

270 CAUSES OF VARIABILITY. Cuar, XXII,

ditions, at least in a visible manner, than the female element or ovule; and
we know from Giirtner’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 variability may be transmitted through either
sexual element, whether or not originally excited in them, for Kélreutey
and Girtner ** found that when two species were crossed, if either one wag

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 inevitable con-
tingent on growth and reproduction, but results from the
conditions to which the parents have been exposed. Changes
of any kind in the conditions of life, even extremely sheht
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 variable 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 conditions before any effect is visible. The
crossing of distinct 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 appear-
ance 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

beings when removed from their natural conditions. The causes
which induce variability act on the mature organism, on the
embryo, and, as we have good reason to believe, on both sexual
elements before impregnation has been effected.

8 ‘ Dritte Fortsetzung,’ &c., s. 123; ‘ Bastarderzeugung,’ s. 249.

Cuap, XXII. DEFINITE ACTION OF CONDITIONS OF LIFE. 271

CHAPTER XXIII.

DIRECT AND DEFINITE ACTION OF THE EXTERNAL CONDITIONS
OF LIFE.

SLIGHT MODIFICATIONS IN PLANTS FROM THE DEFINITE ACTION OF CHANGED CONDI-
TIONS, IN SIZE, COLOUR, CHEMICAL PROPERTIES, AND IN THE STATE OF THE TISSUES
— LOCAL DISEASES —- CONSPICUOUS 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 CON-
DITIONS —- COMPARISON OF AMERICAN AND EUROPEAN TREES — GALLS — EFFECTS
OF PARASITIC FUNGI — CONSIDERATIONS OPPOSED TO THE BELIEF IN THE POTENT
INFLUENCE OF CHANGED EXTERNAL CONDITIONS — PARALLEL SERIES OF VARIETIES
—— AMOUNT OF VARIATION DOES NOT CORRESPOND WITH THE DEGREE OF CHANGE IN
THE CONDITIONS —- BUD-VARIATION —- MONSTROSITIES PRODUCED BY UNNATURAL
TREATMENT — SUMMARY.

Ir we ask ourselves why this or that character has been modi-
fied 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 diversities 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 physical
conditions of life, all, or nearly all the individuals, are modified
in the same manner. A new sub-variety would thus be pro-
duced 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 various organs.
Modifications of this nature, no doubt, are definitely caused by
the conditions to which the beings are subjected; but they de-
pend much less on the nature of the conditions than on the laws
of growth; hence they are included under a distinct head in the

272 DEFINITE ACTION OF TILE Cuap. XXII.

following chapter. We know, however, far too little of the
causes and laws of variation to make a sound classification,
The direct action of the conditions of life, whether leading to
definite or indefinite results, is a totally distinct consideration
from the effects of natural selection; for natural selection
depends on the survival under various and complex circum-
stances of the best-fitted individuals, but has no relation
whatever to the primary cause of any modification 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 organisation of our domesti-
cated productions, that they have sufficed to form new gub-
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 domes-
ticated 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
conclusion of many authors. But we should bear in mind
that man annually has to choose which animals shall be pre-
served for breeding, and which shall be slaughtered. We have
also seen that both methodical and unconscious selection were
formerly practised, 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 instance, the several dis-
tricts in England, could have sufficed 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 during many ages throughout Great Britain, and still
retain the same character, the difference in conditions between
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 distinguishing between selection
and the definite effects of the conditions of life, is encountered in
a still higher degree when we compare closely allied natural

Cuap, XXIII. CONDITIONS OF LIFE, 278

forms, inhabiting two countries, such as North America and
Europe, which do not differ greatly in climate, nature of soil, &c.,
for in this case natural selection will inevitably and rigorously
have acted during a long succession of ages.

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 slight
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 unstable condition. Ornamental flowers
are good for this purpose, as they are highly variable, and are carefully
observed. All floriculturists 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 Picotees,
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 Birmingham? Yet in no two of these
“districts do the same varieties attain an equal degree of excellence,
“although each may be receiving the attention of the most skilful culti-
“vators.” 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 with, for without such
“attention all hope of general success will be vain.” So it is with the
Dahlia :* 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® states that he procured cuttings of an old and well-known
variety (pulchella) of Verbena, which from having been propagated in a
different situation presented 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 varieties
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 Rose came so untrue in cha-
racter, “that it was hardly possible to recognise them, and the thought
“was not seldom entertained that the grower had lost hig tally.” The
same amateur? states that in 1862 two-thirds of his Auriculas produced
central trusses of flowers, and these are remarkable from not keeping true;

' *Gardener’s Chronicle,’ 1853, p. * Mr. Robson, in ‘ Journal of Horti-
183. culture,’ Feb. 13th, 1866, Pp: 122,

2 Mr. Wildman, ‘ Floricultural Soc.,’ 4 ¢ Journal of Horticulture, 1861, p.
Feb. 7, 1843, reported in ‘Gard. Chron., 24.
1843, p. 86. 5 Tbid., 1862, p. 83.

VOU et Te Ab

274 DEFINITE ACTION OF THE CuAp, XXIII,

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
Chronicle’® remarked how singular it was that this year many Calceolariag
tended to assume a tubular form. With Heartsease? the blotched sorts do
not acquire their proper character until hot weather sets in; whilst other
varieties lose their beautiful marks as soon as this occurs.

Analogous facts have been observed with leaves: Mr. Beaton asserts’
that he raised at Shrubland, during six years, twenty thousand seedlings
from the Punch Pelargonium, and not one had variegated leaves; but at
Surbiton, in Surrey, one-third, or even a greater proportion, of the seed-
lings from this same variety were more or 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. Verlot® states that
the variegated strawberry 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 simulta-
neously became variegated, and what made the case more extraordinary,
all were variegated in precisely the same manner. 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 properties 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 Pistacia lentiscus grows abundantly in the South
of France, the climate must suit it, but it yields no mastic. The Lawrus
sassafras in Europe loses the odour proper to it in North America.”
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." 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

6 «Gard. Chron.,’ 1845, p. 660. Dalibert’s Experiments, quoted by
7 Thid., 1863, p. 628. Beckman, ‘Inventions,’ vol. ii. p- 3445
8 Journal of Hort.,’ 1861, pp. 64, and Nees, in Ferussac, ‘ Bull. des Se.
309. Nat.,’ 1824, tom. i. p. 60. With respect
° “Des Varictés,’ &e., p. 76. to the rhubarb, &e., see also ‘ Gardener §

10 Engel, ‘Sur les Prop. Médicales Chronicle,’ 1849, p. 355; 1862, P-
des Plantes,’ 1860, pp. 10, 25. On 1123.
changes in the odours of plants, see 1 Hooker, ‘Flora Indica,’ p. 32.

* Cuap. XXIII. CONDITIONS OF LIFE, 275

and useless. Hemp, on the other hand, fails to produce in England
that resinous matter which is so largely used in India ag an intoxicating
drug.

The fruit of the Melon is greatly influenced by slight differences in cul-
ture and climate. Hence it is generally a better plan, according to Naudin,
to improve an old kind ‘than to introduce a new one into any locality.
The seed of the Persian Melon produces near Paris fruit inferior to the
poorest market kinds, but at Bordeaux yields delicious fruit? Seed. is
annually brought from Thibet to Kashmir," 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
magnificent 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 Rev. M. J. Berkeley
found that their beauty could hardly ever be preserved in England, and in
Some cases the colour was greatly changed. 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 new climate or to different treat-
ment, 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."*> Humboldt remarks’ 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 Puler 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 is not so surprising as it at first appears; for

® Naudin, ‘Annales des Se. Nat.,’ ® Royle, ‘Productive Resources of
4th series, Bot., tom. xi. 1859, p. 81. India,’ p. 59.
‘ Gardener’s Chronicle,’ 1859, p. 464. 16 « Personal N arrative,’ Eng, translat.,
13 Moorcroft’s ‘Travels,’ &c., vol. ii. vol. v. p- 101. This statement has been
p. 143. confirmed by Karsten (¢ Beitrag zur
4 *Gardener’s Chronicle,’ 1861, p, | Kenntniss der Rhynchoprion:’ Moscow,
1413, 1864, s, 39), and by others,
i2

276 DEFINITE ACTION OF THE Cuar. XXL «

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 circumstances on the
human body. Diseases confined to certain races of man do not concerp
us, for the constitution of the race may play the more important part, and
this may have been determined by unknown causes. The Plica Polonicg
stands, in this respect, in a nearly intermediate position; for it rarely affects
Germans, who inhabit the neighbourhood of the Vistula, where so many
Poles are grievously affected; and on the other hand, it does not affect.
Russians, who are said to belong to the same original stock with the
Poles.2 The elevation of a district often governs the appearance of
diseases; in Mexico the yellow fever does not extend above 924 métres:
and in Peru, people are affected with the verugas only between 600 and
1600 métres 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 scarlet-fever is dreaded like the Plague; analogous facts
have been observed in Chili and Mexico.” Even in the different depart-
ments of France it is found that the various infirmities which render the
conscript unfit for serving in the army, prevail with remarkable inequality,
revealing, as Boudin observes, that many of them are endemic, which
otherwise would never have been suspected.” 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 extremely
slight, and in most cases have been caused, as far as we can
judge, by equally slight changes in the conditions. 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 4
period. A good observer” states that a general absence of fat,

17 ‘OrganicChemistry, Eng.translat., taken from Dr. Boudin’s ‘ Géographie
Ist edit., p. 369. et de Statistique Médicales, 1857, tom.

18 Prichard, ‘Phys. Hist. of Mankind,’ i, p. xliv. and lii.; tom. ii. p. 319.
1851, vol. i. p. 155, 21 1). Desor, quoted in the ‘ Anthrop.

19 Darwin, ‘Journal of Researches,’ Reyv.,’ 1863, p. 180. For much confirma-
1845, p. 434. tory evidence, see Quatrefages, ‘Unite

*» These statements on disease are de I’Esptce Humaine,’ 1861, p. 131. .

ye

Cuar, XXII. CONDITIONS OF LIFE. 277

a thin and elongated neck, stiff and lank hair, are the chief
characteristics. The change in the nature of the hair is sup-
posed to be caused by the dryness of the atmosphere. If im-
migration 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 go
important that I will give a large additional body of miscellaneous facts,
With plants, a considerable change of climate sometimes produces a con-
Spicuous 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, Prunus 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
directly 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 con-
tinually rise into small stems, and form a growth around the parent-tree.”
The varieties of the cabbage which produce heads in Europe fail to do so
in certain tropical countries. The Rhododendron ciliatum produced at
Kew flowers so much larger and paler-coloured than those which it bears
on its native Himalayan mountain, that Dr. Hooker’ would hardly have
recognised 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 parsnips
prove that abundant nutriment produces a definite and inheritable effect
on the so-called roots, with scarcely any change in other parts of the plant.
Alum directly influences the colour of the flowers of the Hydrangea.”
Dryness seems generally to favour the hairyness or villosity of plants.
Girtner found that hybrid Verbascums 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.” 7° Slight
variations of many kinds, not worth specifying in detail, are retained only as

SSSR ere enc a AD a OME RT

22 ¢ Ceylon,’ by Sir J. E. Tennent, *5 ¢ Journal of Hort. Soc.,’ vol. i. p. 160.

vol. i, 1859, p. 89. 6 See Lecoq, on the Villosity of
23 Godron, ‘De T’Espice,’ tom. ii. p, Plants, ‘Geograph. Bot.,’ tom. iii. pp.
52. 287, 291; Gartner, ‘Bastarderz.,’ s. 261;

“4 ¢ Journal of Horticultural Soc. Mr, Masters, on the Opuntia, in ‘ Gard,
vol, vii., 1852, p. 117. Chronicle, 1846, p. 444.

278 DEFINITE ACTION OF THE

CHAP, XXIII,

long as plants are grown in certain soils, of which Sageret”” gives from his
own experience some instances. Odart, who insists strongly on the per-
manence of the varieties of the grape, admits” that some varieties, when
grown under a different climate or treated 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 affected in size and flavour, the leaves in duration, and the flowers
in appearance.”

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 undergo 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.” ® 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 horse rapidly decreases in size in the Falkland
Islands. From information 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* that the Thibet mastiff and goat, when
brought down from the Himalaya to Kashmir, lose their fine wool. At
Angora not only goats, but shepherd-dogs and eats, have fine fleecy hair,
and Mr. Ainsworth® attributes the thickness of the fleece to the severe
winters, and its silky lustre to the hot summers. Burnes states positively®
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 assured that with two breeds of sheep the wool was slightly
changed by the flocks being pastured in different localities.24 It has been
asserted on good authority ® 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

27 ‘Pom. Phys.,’ p. 136. 31 ‘Natural History Review,’ 1862,

8 “ Ampelographie,’ 1849, p. 19. p. Lik

*9 Gartner, ‘ Bastarderz.,’ s. 606, has 32 ¢ Journal of Roy. Geographical
collected nearly all recorded facts. Soc.,’ vol. ix., 1839, p. 275.
Andrew Knight (in ‘ Transact. Hort. 33 “Travels in Bokhara,’ vol. ili. p.
Soe.,’ vol. ii. p. 160) goes so far as to 151.
maintain that few varieties are abso- 34 See also, on the influence of marshy
lutely permanent in character when pastures on the wool, Godron, ‘L’Espece,
propagated by buds or grafts. tom. li. p. 22.

3° Mr. Blyth, in ‘ Annals and Mag. of 35 Isidore Geoffroy St. Hilaire, ‘ Hist.
Nat. Hist.,’ vol. xx., 1847, p. 391. Nat. Gén.,’ tom. iii. p. 438.

Cuap, XXIII. CONDITIONS OF LIFE. 279

believe that this is in any way related to the nature of the climate to which
they have been exposed.*®

It appears at first sight probable that the increased size, the tendency to
fatten, the early maturity and altered forms of our improved cattle, sheep,
and pigs, have directly resulted from their abundant supply of food. This
is the opinion of many competent judges, and probably is to a great extent
true. But as far as form is concerned, we must not overlook the equal
or more potent influence 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
suppliéd with abundant nourishment. Nevertheless 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.
Riitimeyer® 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 excel-
lent ‘ Vorstudien, ** 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 assume 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 progenitors more or less remote, and the
natural selection of the finest shades of difference.

The nature of the food sometimes either definitely induces certain pecu-
liarities, or stands in some close relation with them. Pallas long ago
asserted that the fat-tailed sheep of Siberia degenerated and lost their enor-
mous tails when removed from certain saline pastures; and recently

36 Azara has made some good remarks Soe.,’ 1856, p. 38.
on this subject, ‘ Quadruptdes du . 7 ‘Die Fauna der Pfahlbauten,’ 1861,
Paraguay, tom. ii. p. 337. See an 5, 15.
account of a family of naked mice 33 ‘ Schweinscheedel,’ 1864, s. 99.
produced in England, ‘ Proce. Zoolog,

980 DEFINITE ACTION OF THE ~ Citar, XX

Erman® states that this occurs with the Kirgisian sheep when brought to
Orenburgh.

It is well known that herp-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 (Chrysotis festivu, 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 analogous manner the colours of another
parrot, namely, the Lorius garrulus, Linn., and thus produce the Lop;
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, re-
corded* a still more singular fact. “The Indians (of S. America) haye
‘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
* inoculate 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” 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”
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. Buck-
land 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* has recorded a much more

‘remarkable case of the same nature, namely, that young shells taken

from the shores of England and placed in the Mediterrancan, at once
altered their manner of growth and formed prominent diverging rays, like
those on the shells of the proper Mediterranean oyster. The same indi-
vidual shell, showing both forms of growth, was exhibited before a society
in Paris. Lastly, it is well known that caterpillars fed on different food

sometimes either themselves acquire a different colour or produce moths
different in colour.*4

% “Travels in Siberia,’ Eng. translat., tom. viii. p. 351,
vol. i. p. 228. 44 See an account of Mr. Gregson’s
4° A. R. Wallace, ‘Travels on the experiments on the Abraxus gross
Amazon and Rio Negro,’ p, 294. lariata, ‘Proc. Entomolog. Soc.,’ Jan.
41 « Naturgeschichte der Stubenvégel,’ 6th, 1862: these experiments have
1840, s. 262, 308. been confirmed by Mr. Greening, in
® “Hist. Nat. Gén.,’ tom. iii. p. 402. ‘Proc. of the Northern Entomolog.
43 ¢ Bull. de la Soe. Imp. d’Acclimat.,’ Soc.,’ July 28th, 1862. For the effects

Cuap, XXIII. CONDITIONS OF LIFE. 281

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 con-
ditions. 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 * has recently dis-
cussed with much ability this whole subject on broad and general grounds.
He argues, for instance, that with all animals the external and internal
tissues are differently acted on by the surrounding conditions, and they
invariably differ in intimate structure. So again the upper and lower sur-
faces of true leaves, as well ag of stems and petioles, when these assume the
function and occupy the position of leaves, are differently circumstanced
with respect to light, &e., and apparently in consequence differ in struc-
ture. 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 serviceable 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, yet I may call attention to one case. Mr.
Meehan,“ in a remarkable paper, compares twenty-nine kinds of
American trees, belonging to various 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
serrated ; 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 ig out of the question 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

of food on caterpillars, see a curious
account by M. Michely, in ‘ Bull. de la
Soc. Imp. d’Acclimat.,’ tom. viii. p. 563.
For analogous facts from Dahlbom on
Hymenoptera, see Westwood’s ‘ Modern
Class. of Insects,’ vol. ii. p.98. See also
Dr. L. Miller, ‘Die Abhangigkeit der
Insecten,’ 1867, s. 70.

* <The Principles of Biology,’ vol,

ii. 1866. The present chapters were
written before I had read Mr. Her-
bert Spencer’s work, so that I have not
been able to make so much use of it
as I should otherwise probably have
done.

46 “Proc. Acad. Nat. Soc. of Phila-
delphia,’ Jan. 28th, 1862.

282 DEFINITE ACTION OF THE CHap, XXIII,

service to the two series in the Old and New Worlds; there-
fore 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 different 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 different galls produced
by the oak. Some of the latter resemble fruit, with one face ag
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 manner 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, Ac-
cording 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. Walsh ® states that he can
add many others to the list. One American species of willow,
the Salix humilis, bears ten distinct kinds of galls. The leaves
which spring from the galls of various English willows ditier
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 become from the same cause wholly changed in
appearance. Galls are produced in every quarter of the world;
of several sent tome 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* has figured in the common ink-gall no
less than seven concentric layers, composed of distinct tissue,

47 See Mr. B. D. Walsh’s excellent 48 See his admirable Histoire des
papers in ‘ Proc. Entomolog. Soc. Phila- Galles, in ‘ Annal. des Sc. Nat. Bot.
delphia,’ Dec. 1866, p.284. With respect 8rd series, tom. xix., 1853, p. 273.
to the willow, see idem, 1864, p. 546.

Cuap, XXIII. CONDITIONS OF LIFE. 283

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 larve feed.

Galls are produced by insects of various orders, but the
greater number by species of Cynips. It is impossible to read
M. Lucaze-Duthier’s 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 rapidity, and it is said that they attain their
full size in a few days ;® it is certain that they are almost com-
pletely developed before the larve 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”
remarks, afford good, constant, and definite characters, each kind
keeping as true to form as does any independent organic being.
This fact becomes still more remarkable when we hear that, for
instance, seven out of the ten different kinds of galls produced
on Salix humilis are formed by gall-gnats (Cectdomyide) which,
“though essentially distinct species, yet resemble one another
“so closely that in almost all cases it is difficult, and in some
“eases impossible, to distinguish the full-grown insects one from
“ the other.”*! For in accordance 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-enat produces on distinct species
of willows galls which” cannot be distinguished; the Cynips
fecundatriz, 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

49 Kirby and Spence’s ‘ Entomology,’ 51 Mr. B. D. Walsh, idem, p. 633 ; and
1818, vol. i. p. 450; Lucaze-Duthiers, Dec. 1866, p. 275.
idem, p. 284. 2 Mr. B, D. Walsh, idem, 1864, p.
50 ¢ Proc. Entomolog. Soc. Phila- 545, 411, 495; and Dec. 1866, p. 278.
delphia,’ 1864, p. 598. See also Lucaze-Duthiers,

284 DEFINITE ACTION OF THE Cuar, XXII,

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 various
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 secreted 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
instance, the mossy and viscid calyx of a moss-rose, which sud-
denly appears through bud-variation on a Provence-rose, with
the gall of red moss growing from the inoculated leaf of a wild
rose, with each filament symmetrically branched like a micro-
scopical spruce-fir, bearing a glandular tip and secreting odo-
riferous gummy matter.’ 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 abnormal structures manifestly present a certain degree
of resemblance. Or, again, reflect on the cases above given of
parrots which have had their plumage brightly decorated through
some change in their blood, caused by having 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 chemical 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 atiect structure. With such facts before us, we need

feel no surprise at the appearance of any modification in any
organic being.

I may, also, here allude to the remarkable effects which parasitic fungi
Sometimes produce on plants. Reissek*4 has described a Thesium, affected
by an Cicidium, which was greatly modified, and assumed some of the

53 Lucaze-Duthiers, idem, pp. 325, 328.

4 Linnea,’ vol. xvii., 1843; quoted by Dr, M. T. Masters, Royal Institution,
March 16th, 1860.

CuHaP, XXIII. CONDITIONS OF LIFE. 285

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 species 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. conditions ;
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 number of animals and plants which
range widely and have been exposed to great diversities of
conditions, yet remain 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 con-
ditions 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 animals, 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 indivi-
duals exposed to nearly the same conditions, and one alone is affected, we
may conclude that the constitution of the individual is of far higher

el th 5 Dd ae
* Hewett C. Watson, ‘Cybele Britannica, vol, i., 1847, p. 11.

286 DEFINITE ACTION OF THE CHAP. XXIII,

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 judge, 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 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 20
on varying in directly opposite ways, though kept during many genera-
tions under nearly the same conditions. Some, for instance, are born with
their beaks, wings, tails, legs, dvc., 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, important 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 indefinite
number of particulars, though treated as uniformly as is possible. 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. Pigeons 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 vegetables have been pro-
duced in North America: these differ from European varieties in the
Same general manner as the several varieties 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 European
forest-trees, it would be rash to affirm that varietics raised in the two
countries would not in the course of ages assume a distinctive character.
Mr. Masters has recorded a striking fact®® 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 conditions; yet the seedlings from both
localities broke into two similar strains, one with obtuse leaves and purple

or crimson flowers, and the other with elongated leaves and more or less
pink flowers.

°° * Gardener’s Chronicle,’ 1857, p. 629.

Cuap. XXIII. CONDITIONS OF LIFE. 287

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 im-
portant 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 corre-
sponding and parallel manner. 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 consequently 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. Maxwell Masters has remarked to me, in the same plant.

We may at least conclude thus far, that the amount of modi-
fication which animals and plants have undergone under domes-
tication, does not correspond with the degree to which they
have been subjected to changed circumstances. 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 Kurope 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 jungles 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
nevertheless have varied in a much higher degree, The goose,
a native of Europe and aquatic like the duck, 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 sudden]
varied in the same manner, it might be argued that the yayia-

288 DEFINITE ACTION OF THE CHAP, XXIII,

tion 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 some-
times appear by bud-variation, which do not occur in the parent.
species or in any allied species, we may reject, at least in these

- eases, the idea that they are due to reversion. Now it is well

worth while to reflect maturely 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 various
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 nec-
tarines. Nectarines 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 speci-
fically distinct. So permanent are the characters thus suddenly
acquired, that a nectarine produced by bud-variation has pro-
pagated 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 like-
wise been produced from the stone of the peach; and, reversely,
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 exposed? Yet one bud
alone, out of the many thousands borne by the same tree, has
suddenly without any apparent 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 nectarines:
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 conditions of life are quite insignificant in

Gan et me m*/ <— ==

Cuap, XXIII. CONDITIONS OF LIFE. 289

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, &¢., produce monstrous chickens. Now these monstro-
sities may be said to be directly caused by such unnatural con-
ditions, but the modifications thus induced are not of a definite
nature. An excellent observer, M. Camille Dareste,” remarks
“that the various species of monstrosities are not determined
“by specific causes; the external agencies which modify the
“development of the embryo act solely in causing a pertur-
“bation—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 many, causing
either a cold, or sore-throat, rheumatism, or inflammation of the
lungs or pleura. Contagious matter acts in an analogous manner.”
We may take a still more specific instance: seven pigeons were
struck by rattle-snakes ;°° 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 differently affected: 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 conditions act directly, though
not definitely, in causing modifications of structure,

Summary.—There can be no doubt, from the facts given in
the early part of this chapter, that extremely slight changes in

7 «Mémoire sur la Production Arti- Pathology,’ 1853, vol. i. p. 483. ”

ficielle des Monstrosités,’ 1862, pp. 8-12;
‘Recherches sur les Conditions, &c.,
chez les Monstres,’ 1863, p. 6. An ab-
stract is given of Geoffroy’s Experi-
ments by his son, in his ‘ Vie, Travaux,
&c.,’ 1847, p. 290.

58 Paget, ‘Lectures

VOL. II.

on Surgical

59 «Researches upon the Venom of
the Rattle-snake,’ Jan. 1861, by Dr,
Mitchell, p. 67.

60 Mr. Sedgwick, in ‘British and
Foreign Medico-Chirurg. Review,’ July,
1863, p. 175.

U

290 DEFINITE ACTION OF THE Cap, XXIII,

the conditions of life sometimes act in a definite manner on
our already variable domesticated productions ; and, as the action
of changed conditions in causing general or indefinite varia-
bility is accumulative, so it may be with their definite action,
Hence it is possible that great and definite modifications of struc.
ture 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 considerable change of climate,
food, or other circumstance. This has occurred, and is now
occurring, with European men in the United States, with Euro-
pean dogs in India, with horses in the Falkland Islands, appa-
rently with various animals at Angora, with foreign oysters
in the Mediterranean, 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 appa-
rently 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 mysterious changes in structure
and colour may be the definite result of chemical changes in the
nutrient fluids or tissues.

We have also reason to believe that organic beings in a state
of nature may be modified in various definite ways by the con-
ditions to which they have been long exposed, as in the case
of American trees in comparison with their representatives
Europe. But in all such cases it is most difficult to distinguish
between the definite results of changed conditions, and the ac
cumulation 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

ALA

eS

Cuap, XXIII CONDITIONS OF LIFE. 291

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 more important
element than the nature of the changed conditions, in deter-
mining 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
Taces, or even distinct species, and in the frequent 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 reflect on
the millions of buds which many trees have produced, 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 sud-
denly produced the red magnum bonum. We should also
bear in mind that distinct varieties, and even ‘distinct spe-
cles,—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 common, and
although cultivated under diversified conditions, 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 conditions to which the pl

ant 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

oup of allied beings to which

driven to conclude that in most
u 2

remote progenitor, of the whole er
the plant belongs. We are thus

292, DEFINITE ACTION OF CONDITIONS OF LIFE, Cuap, XXII,

eases 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 modifications resulting from the
definite action of the conditions of life, when all or nearly all
the individuals, which have been similarly exposed, are simi-
larly affected, we can rarely 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 manner 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, rever-
sion, 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 definitely
affect organic beings, it may be doubted whether well-marked
races have often been produced by the direct action of changed

conditions without the aid of selection either by man ot
nature.

naray
ids

Cuap, XXIV. LAWS OF VARIATION: NISUS FORMATIVUS. 293

CHAPTER XXIV.

LAWS OF VARIATION—USE AND DISUSE, ETC.

NISUS FORMATIVUS, OR THE CO-ORDINATING POWER OF THE ORGANISATION == 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,

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—correlated variation—the cohesion of
homologous parts—the variability of multiple parts—compensa-
tion 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 desig-
nated 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 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 likewise with the budding of plants. Between
these extreme cases and that of a mere cicatrice we have every gradation.
Spallanzani,? 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

spe ere se cite
1*An Essay on Generation,’ Eng, 2 *An Essay on Animal Reproduc-

translat., p. 18; Paget, ‘Lectures on tion, Eng. translat., 1769, p. 79.
Surgical Pathology,’ 1853, vol. i. p. 209.

294. LAWS OF VARIATION. Cuap, XXIV C

point the limb was cut off, the deficient part, and no more, wag exactly hy
reproduced. Even with man, as we have seen in the twelfth chapter, nt
when treating of polydactylism, the entire limb whilst in an embryonic gh
state, and supernumerary digits, are occasionally, though imperfectly, ly
reproduced after amputation. When a diseased bone has been removed, ¥
a new one sometimes “gradually assumes the regular form, and all the br
“ attachments of muscles, ligaments, &c., become as complete as before.”3 . m

This power of regrowth does not, however, always act perfectly : the res
reproduced tail of a lizard differs m the forms of the scales from the normal is
tail: with certain Orthopterous insects the large hind legs are reproduced os
of smaller size:+ the white cicatrice which,in the higher animals unites “t
the edges of a deep wound is not formed of perfect skin, for clastic . i,
tissue is not produced till long afterwards.> “ The activity of the nisus :
“ formativus,” says Blumenbach, “is in an inverse ratio to the age of the ad
“organised body.” To this may be added that its power is greater in oc
animals the lower they are in the scale of organisation; and animals low de
in the scale correspond with the embryos of higher animals belonging to es
the same class. Newport’s observations® afford a good illustration of this su
fact, for he found that “ myriapods, whose highest development scarcely or
“carries them beyond the larvee of perfect insects, can regenerate limbs and vi
“antennee up to the time of their last moult;” and so can the larve of true ti
insects, but not the mature insect. Salamanders correspond in develop- @

ment with the tadpoles or larve 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 injuries,
When a bone is broken, and does not unite, the ends are absorbed and

rounded, so that a false joint is formed; or if the ends unite, but overlap, in
the projecting parts are removed.’ But absorption comes into action, as +
Virchow remarks, during the normal growth of bones; parts which are
solid during youth become hollowed out for the medullary tissue as the No
bone increases in size. In trying to understand the many well-adapted P|
cases of regrowth when aided by ‘absorption, we should remember that ay
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 tc
reproduced, but structures which appear new are formed. Thus, after P
inflammation “ false membranes,” furnished with blood-vessels, lymphatics, |
and nerves, are developed; or a foetus escapes from the Fallopian tubes, ¥
and falls into the abdomen, “nature pours out a quantity of plasti¢ St

“lymph, which forms itself into organised membrane, richly supplied with
“ blood-vessels,” and the foetus is nourished for atime. In certain cases of

* Carpenter’s ‘Principles of Comp. 5 Paget, ‘ Lectures on Surgical Patho- 82
Physiology,’ 1854, p. 479. logy,’ vol. i. p. 239. 3

* Charlesworth’s ‘Mag. of Nat, Hist.,’ ° Quoted by Carpenter, ‘ Comp. Phys. Ch
Vol. i. 1887, p. 145. p.479. 7 Paget, ‘ Lectures,’ &c., P- 207 |

© aWVeAa,

Cuar, XXIV. EFFECTS OF USE AND DISUSE, 295

hydrocephalus the open and dangerous spaces in the skull are filled up with
new bones, which interlock by perfect serrated sutures.’ But most physiolo-
gists, especially on the Continent, have how given up the belief in plastic
lymph or blastema, and Virchow* maintains that every structure, new or old,
is formed by the proliferation of pre-existing cells. On this view false mem-
branes, like cancerous or other tumours, are merely abnormal develop-
ments of normal growths; and we can thus understand how it is that they
resemble adjoining structures ; for instance, that “ false membrane in the
“ serous cavities acquires a covering of epithelium exactly like that which
“ eovyers the original serous membrane; adhesions of the iris may become
“ black apparently from the production of pigment-cells like those of the
10

No doubt the power of reparation, though not always quite perfect, 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 won-
derful than the growth and development of every single creature, more
especially of those which arg propagated by fissiparous generation. This
subject has been here noticed, because we may infer that, when any part
or organ is either greatly increased in size or wholly suppressed through
variation and continued selection, the co-ordinating power of the organisa-
tion will continually 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 explanation of this fact in works on
Physiology. Mr. Herbert Spencer” maintains that when muscles
are much used, or when intermittent pressure is applied to the
epidermis, 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 thus accounts for the long, thick, and dark-coloured hair
which occasionally grows, even in young children, near old-
standing inflamed surfaces or fractured bones. When Hunter

* These cases are given by Blumen- vol. i, 1853, p. 357.

bach in his ‘Essay on Generation,’ pp. 11 Paget, idem, p. 150.

52, 5, 12 «Phe Principles of Biology,’ vol.
® “Cellular Pathology,’ trans. by Dr. ii. 1866, chap. 3-5.

Chance, 1860, pp. 27, 441. 13 «Lectures on Pathology,’ 18538,

© Paget, ‘Lectures on Pathology? vol. i. p. 71.

296 LAWS OF VARIATION.

CHAP. XXIV,

inserted the spur of a cock into the comb, which is well supplied
with blood-vessels, it grew in one case in a spiral direction 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 movement and pressure, will fully
account for the augmented size of bones, ligaments, and espe-
cially of internal glands and nerves, seems doubtful. Ac.
cording to the interesting observations of M. Sedillot,“ when
a portion of one bone of the leg or fore-arm of an animal js
removed 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 removed; the companion
bone, which is naturally almost filiform 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
diminished pressure, cause nutritive matter to exude from the
vessels which permeate the periosteum. Nevertheless, the obser-.
vations adduced by Mr. Spencer, on the strengthening 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 proportion 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 tissue, and the greater the thickening of
“ this tissue by secondary deposits.” !° 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 ig very difficult to disentangle the
effects of long-continued selection from those consequent oD
the increased action or movement of the part. Mr. H. Spencer”
acknowledges this difficulty, and gives as an instance the spines

™ “Comptes Rendus,’ Sept. 26th, 1864, p. 539.
® <The Principles of Biology,’ vol. ii. p. 243.
© Idem, vol. ii. p. 269. 7 Idem, vol. ii. p. 273.

Vili

Desc

Cuap. XXIV. EFFECTS OF USE AND DISUSE. 297

or thorns of trees, and the shells of nuts. Here we have ex-

tremely hard woody tissue without the possibility of any move-
ment 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
result as probably due to the selection of so-called spontaneous
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 ob-
served with admiration by Albinus,'* 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 be seen in the limbs of artisans
who follow different trades ; and when a muscle is strengthened, 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 be-
comes atrophied, sometimes even in the course of a few months.” The
Proteus is furnished with branchise as well as with lungs: and Schreibers”°
found that when the animal was compelled to live in deep water the
branchie were developed to thrice their ordinary size, and the lungs were
partially atrophied. When, on the other hand, the animal was compelled to
live in shallow water, the lungs became larger and more vascular, whilst
the branchize disappeared in a more or less complete degree. Such modifi-
cations as these are, however, of comparatively 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 use 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 genera-
tion. It appears, as in the case of general or indefinite variability, that
several generations must be subjected to changed habits for any appreci-
able result. Our domestic fowls, ducks, and geese have almost lost, not

WERE ye a Se eae

'S Paget, ‘Lectures on Pathology,’ p- 10) a curious account of the atrophy
vol. ii. p. 209. of the limbs of rabbits after the de-
9 Miiller’s ‘Phys.’ Eng. translat., struction of the nerve.
pp. 54, 791. Prof. Reed has given 20 Quoted by Lecoq, in ‘ Geograph.
(‘ Physiological and Anat. Researches,’ Bot.,’ tom. i. 1854, p. 182.

298 LAWS OF VARIATION. Cnar, XXIy, (

only in the individual but in the race, their power of flight; for we da’ b
not see a chicken, when frightened, take flight like a young pheasant,
Hence I was led carefully to compare the limb-bones of fowls, ducks, pigeons,
and rabbits, with the same bones in the wild parent-species. Ag the di
measurements and weights were fully given in the earlier chapters, I need
here only recapitulate the results. With domestic pigeons, the length of
the sternum, the prominence of its crest, the length of the Scapule and

: ' ni
furcula, the length of the wings as measured from tip to tip of the radius, 4
are all reduced relatively to the same parts in the wild pigeon. The wing hi
and tail feathers, however, are increased in length, but this may have ag de

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 hag 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 ig to
often distorted or monstrous; the wing-bones have become lighter rela- pt
tively 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 i
: 5 : ; I
of the sternum is affected in the same manner as in the foregoing cases:
the furcula, coracoids, and scapule are all reduced in weight relatively to b
the whole skeleton: the bones of the wings are shorter and lighter, and u

the bones of the legs longer and heavier, relatively to cach other, and rela
tively to the whole skeleton, in comparison with the same bones in the
wild-duck. The decreased weight and size of the bones, in the foregoing e
cases, is probably the indirect result of the reaction of the weakened 8
muscles on the bones. I failed to compare the feathers of the wings of
the tame and wild duck; but Gloger” asserts that in the wild duck the

tips of the wing-feathers reach almost to the end of the tail, whilst in i
the domestic duck they often hardly reach to its base. He remarks, also, a
on the greater thickness of the legs, and says that the swimming mem- th
brane between the toes is reduced; but I was not able to detect this latter a
difference. he
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 t
are heavier in due proportion; but whatever standard of comparison be 1
taken, neither the leg-bones nor the scapule have increased in length t
proportionally with the increased dimensions of the rest of the skeleton.
The skull has become in a marked manner narrower, and, from the mea- :
surements of its capacity formerly given, we may conclude, that this nar- r
rowness results from the decreased size of the brain, consequent on the ti
mentally inactive life led by these closely-confined animals. l
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, ot
even, according to Quatrefages, quite rudimentary. This condition of the a
wings may be largely owing to the same kind of monstrosity which often ca
affects wild Lepidoptera when artificially reared from the cocoon ; or it may
Se

‘Das Abandern der Vogel,’ 1833, s. 74. ,

Cuap, XXIV. EFFECTS OF USE AND DISUSE, 259

be in part due to an inherent tendency, which is common to the females
of many Bombycide, 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,
lave 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 extending this latter conclusion
to animals living a free life; for these will occasionally be ex-
posed 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 do-
mesticated 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 condyles of the occiput, and
the position of the jaws with the upper canine teeth projecting in
a most 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, nor
root up the ground with their rmged muzzles. These modifica-
tions of structure, which are all strictly inherited, characterise
several improved breeds, so that they cannot have been de-
rived 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 compared with those possessed by animals
“‘ having perfect liberty ;”*? 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 ob-

2 Nathusius, ‘Die Racen des g, 103, 130, 133.

studien ... . Schweineschidel,’ 1864, land Soe.,’ July, 1860, p. 321.

300 LAWS OF VARIATION,

CHAP, XXIV,

vious ; and perhaps the liver may be affected by the nutritious
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 extension, 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 hag Te-
marked,” with respect to the branches of arteries, and likewise to a certain
extent with nerves, that the great principle of compensation 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 ori-
ginal variation, and how far to increased use or action, is not clear.

In reference to glands, Mr. Paget observes that “when one kidney ig
“ destroyed the other often becomes much larger, and does double work.” 2
If we compare the size of the udders and their power of secretion in cows
which have been long domesticated, and in certain goats in which the udders
nearly touch the ground, with the size and power of secretion of these organs
in wild or half-domesticated 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 Africa,”
“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 certain 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 continually directed
towards a near object permanently affects the structure of the eye.

Veterinarians are unanimous that horses become affected with spavins,
splints, ringbones, &c., from being shod, and from travellin g 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.”

*4 ‘Principles of Biology,’ vol. ii. p, 263. Africa,’ p. 318. For analogous cases in
* «Natural History Review,’ vol. iv., South America, see Aug. St. Hilaire,

Oct., 1864, p. 617. ‘Voyage dans le Province de Goyad,
6 «Lectures on Surgical Pathology, tom. i. p. 71.

1853, vol. i. p. 27. °8 Brickell's ‘Nat. Hist. of North
7 Andersson, ‘Travels in South Carolina,’ 1739, p. 53,

Cuap, XXIV. EFFECTS OF USE AND DISUSE. 301

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 drooping 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 animals, which constantly use their ears
like funnels to catch every passing sound, and especially to
ascertain the direction whence it comes, there is not, as Mr.
Blyth has remarked, any species with drooping ears except
the elephant. Hence the incapacity to erect the ears is cer-
tainly in some manner the result of domestication; and this
incapacity has been attributed by various authors” to disuse, for
animals protected by man are not compelled habitually to use
their ears. Col. Hamilton Smith” states that in.ancient effigies
of the dog, “with the exception of one Egyptian instance,
“no sculpture of the earlier Grecian era produces representations
‘ of hounds with completely drooping ears; those with them half
“ pendulous are missing in the most ancient; and this character
“increases, by degrees, in the works of the Roman period.”
Godron also has remarked that “the pigs of the ancient Keyptians
“had not their ears enlarged and pendent.”®! But it is remark-
able 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.

9 Livingstone, quoted by Youatt on *° “Naturalist Library,’ Dogs, vol. ii.,
Sheep, p. 142. Hodgson, in ‘ Journal 1840, p. 104.
of Asiatic Soc. of Bengal,’ vol, xvi,, ‘De VEsptce, tom, i, 1859, p.
1847, p. 1006, &e. &e, 367,

302 LAWS OF VARIATION. Cuap, XXIV

The epidermis on our hands is easily thickened, as every one
knows, by hard work. In a district of Ceylon the sheep haye
“ horny callosities that defend their knees, and which arise from
“their habit of kneeling down to crop the short herbage, anq
“ this distinguishes the Jaffna flocks from those of other portions
“of the island;” but it is not stated whether this peculiarity
is inherited.*

The mucous membrane which lines the stomach is continuous
with the external skin of the body ; therefore it is not surprising
that its texture should be effected by the nature of the food
consumed, but other and more interesting changes likewise
follow. Hunter long ago observed that the muscular coat of the
stomach of a gull (Larus 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
Islands in the stomach of the Larus 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 vegetable food. In the
case of an owl (Strix grallaria) similarly treated, Menetries states
that the form of the stomach was changed, the inner coat became
leathery, and the liver increased in size. Whether these modi-
fications in the digestive organs would in the course of genera-
tions become inherited is not known.*

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. Ac-
cording 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 domestic
animal, yet, as Isidore Geoffroy has remarked, the several species,

32 «Ceylon, by Sir J. E. Tennent, as quoted in Macgillivray’s ‘ British
1859, vol. ii, p. 531. Birds,’ vol. v. p. 550: Menetries, 8
33 For the foregoing statements, see quoted in Bronn’s ‘Geschichte det
Hunter’s ‘Essays and Observations, Natur,’ B. ii, s. 110.
1861, vol, ii, p, 329; Dr. Edmondston,

SUA)

s co
._ea & . =.
= = = S&S

Cuap, XXIV. CHANGED HABITS OF LIFE. 303

of cats are so closely allied that the comparison 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 French kitten eating vegetables
as readily as meat. According to Cuvier, 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.*4

Changed Habits of Life, independently of the Use or Disuse
of particular 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 domes-
tication, and which are familiar to every one—for instance the
tameness 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 additional instances
may here be given.

In the Polynesian Islands and in China the dog is fed exclu-
sively on vegetable matter, and the taste for this kind of
food is to a certain extent inherited.» Our sporting 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 it.* One of my relations bred some young pigs from

34 These statements on the intestines bourne,’ 1825, vol. ii. p. 121.

are taken from Isidore Geoffroy St, 36 Burdach, ‘Traité de Phys.,’ tom.
Hilaire, ‘ Hist. Nat. Gén.,’ tom. iii, pp. ii p. 267, as quoted by Dr. P. Lucas,
427, 445, ‘L’Heréd, Nat.,’ tom. i, p, 388,

3 Gilbert White, ‘Nat. Hist. Sel-

304 | LAWS OF VARIATION, Cuap, XXIV

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 devoured by
the other pigs. An animal when once accustomed to an un-
natural diet, which can generally be effected only during youth,
dislikes its proper food, as Spallanzani found to be the cage
with a pigeon which had been long fed on meat. Individuals
of the same species 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 Bombyx hesperus feed in a state of
nature on the leaves of the Café diable, but, after having been
reared on the Ailanthus, they would not touch the Café diabke,
and actually died of hunger.*

It has been found possible to accustom marine fish to liye
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 subject. 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 the rate of change in the season has been recorded.”
The wild drake pairs with one female, the domestic drake is
polygamous. 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 silent, as in the Call and
common duck, or in the Spitz and pointer dog. very 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,

37 This and several other cases are Soc, d’Acclimat.’ tom. viii, 1861, P.
given by Colin, ‘ Physiologie Comp. des —_563. F
Animaux Dom.,’ 1854, tom. i. p. 426. 39 Quatrefages, ‘Unité de )’Espece

38 M. Michely de Cayenne, in‘Bull. Humaine,’ 1861, p. 79,

Car, XXIY. ACCLIMATISATION, 305

and vetches; but to this subject we shall immediately return
under acclimatisation. Annual plants sometimes become peren-
nial under a new climate, as I hear from Dr. Hooker is the case
with the stock and mignonette in Tasmania. On the other
hand, perennials sometimes become annuals, as with the Ricinus
in England, and as, according to Captain Mangles, with many
varieties of the heartsease. Von Berg“ raised from seed of
Verbascum phenicium, which is usually a biennial, both annual
and perennial varieties. Some deciduous bushes become ever-
green in hot countries.“ Rice requires much water, but there is
one variety in India which can be grown without irrigation.”
Certain varieties of the oat and of our other cereals are best fitted
for certain soils® 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.

Acelimatisation—F rom the previous remarks we are naturally
led to the much disputed subject of acclimatisation. There are
two distinct questions: Do varieties descended from the same
species differ in their power of living under different climates ?
And secondly, if they so differ, how have they become thus
adapted? We have seen that European dogs do not succeed
well in India, and it is asserted,“ that no one has succeeded in
there keeping the Newfoundland long alive; but then it may be
argued, probably with truth, that these northern breeds are speci-
fically distinct from the native dogs which flourish in India. The
same remark may be made with respect to different breeds of
sheep, of which, according to Youatt,” not one brought “ from
“a torrid climate lasts out the second year,” in the Zoological
Gardens. But sheep are capable of some degree of acclimatisation,
for Merino sheep bred at the Cape of Good Hope have been found

40 ‘Flora,’ 1835, B. ii. p. 504. 48 ¢Gardener’s Chronicle,’ 1850, pp.
41 Alph. De Candolle, ‘ Géograph, 204, 219.

Bot.,’ tom, ii. p. 1078. 44 Rey. R. Everest, ‘ Journal As, Soc.
® Royle, ‘ Illustrations of the Botany of Bengal, vol. iii. p. 19.

of the Himalaya,’ p. 19, * Youatt on Sheep, 1838, p. 491.

_ VOL, II. x

306 LAWS OF VARIATION. CHAP, XXIV

far better adapted for India than those imported from England.
It is almost certain that the breeds of the fowl are descended
from the same species; but the Spanish breed, which there jg
good reason to believe originated near the Mediterranean,
though so fine and vigorous in England, suffers more from frost
than any other breed. 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 caterpillar, cocoon, and mature
states ;*° 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 temperate countries; whilst
the cultivated plants are widely dissimilar. Hence a larger field is open
for inquiry in regard to the acclimatisation of plants than of animals. It
is no exaggeration to say that with almost every plant which has long
been cultivated varieties exist, which are endowed with constitutions fitted
for very different climates; 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 instance,
in Downing,—lists are given of the varieties which are best able to with-
stand 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 with-
stand a severer winter than ours, the summer here is not hot enough.
Fruit-trees have originated in Europe as in America with different consti-
tutions, 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 impu-
nity a frost of 18° and even 14° Fahr., which killed the flowers, whether fully
expanded or in bud, of all other kinds of pears.” This power in the flower
of resisting cold and afterwards producing fruit does not invariably de-
pend, as we know on good authority, on general constitutional vigour.

46 Royle, ‘ Prod. Resources of India, 49 See remarks by Editor in ‘ Gard.
p. 153. Chronicle,’ 1848, p. 5.

* Tegetmeier, ‘ Poultry Book, 1866, 50 ‘Gard. Chronicle’ 1860, p. 938.
p. 102. Remarks by Editor and quotation from
*8 Dr. R. Paterson, in a paper com- Decaisne. ?
municated to Bot. Soc. of Canada, 51 J, de Jonghe, of Brussels, 12

quoted in the ‘ Reader, 1863, Nov. 13th. ‘ Gard. Chronicle,’ 1857, p. 612.

by it
adapta
may b
SOWN 1
as if it

Bota

Crap, XXIV. ACCLIMATISATION, 307

In proceeding northward, 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
neighbourhood of Stockholm.®2 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.*3 We thus
see that our fruit-trees, like distinct Species of the same genus, certainly
differ from each other in their constitutional adaptation 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 cultivation in Scotland ;” ** 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 yielded a good crop from English wheat. 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.” 5 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 a winter or summer variety, when
sown under the warmer climate of Grignan, in France, behaved exactly
as if it had been a true winter wheat.°7

Botanists believe that all the varieties of maize belong to the same
Species; and we have seen that in North America, in proceeding north-
ward, 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
further 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.®® On the authority of the great Linnzus,*® I may quote an

_* Ch, Martius, ‘Voyage Bot. Cotes *7 MM. Edwards and Colin, ¢ Annal.

Sept. de la Norvege,’ p. 26, des Se. Nat.” 2nd series, Bot., tom. v. p.22.
°3 ¢ Journal de l’Acad. Hort. de Gand,’ °8 Géograph, Bot.,’ p. 337.

quoted in ‘Gard, Chron.,’ 1859, p. 7. *° “Swedish Acts, Eng. translat.,
** ‘Gard. Chronicle,’ 1851, p, 396, 1739-40, vol. i, Kalm, in his ‘ Travels,
°° Idem., 1862, p. 235. vol. ii. p. 166, gives an analogous case
°6 On the authority of Labat, quoted with cotton-plants raised in New Jersey

in ‘Gard, Chron., 1862, p, 235, from Carolina seed,

x 2

308 LAWS OF VARIATION.

analogous case, namely, that in Sweden tobacco 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 culture
has retreated a little southward since the middle ages; 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 ig
however, a marked difference in the constitution of the-several varieties —
some being hardy, whilst others, like the muscat of Alexandria, require a,
very high temperature to come to perfection. According to Labat, vinog
taken from France to the West Indies succeed with extreme difficulty, whilst
those imported from Madeira, or the Canary Islands, thrive admirably,

Gallesio gives a curious account of the naturalisation of the Orange in
Italy. During many centuries the sweet orange was propagated excly-
sively by grafts, and so often suffered from frosts that it required protection,
After the severe frost of 1709, and more especially after that of 1763, so
many trees were destroyed that seedlings from the sweet orange were
raised, and, to the surprise of the inhabitants, 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.” I may add that Risso® describes some
Portuguese varieties of the orange as extremely sensitive to cold, and as
much tenderer than certain other varieties.

The peach was known to Theophrastus, 322 3.c.°4 According to the
authorities quoted by Dr. F. Rolle,® it was tender when first introduced
into Greece, and even in the island of Rhodes only occasionally 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 hardire.
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.” ©

I will briefly give a few other cases. A variety of Magnolia grandiflora,
raised by M. 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

De Candolle, ‘Géograph. Bot.,’ p. 1813, p. 20, &e.

339. 5 Alph. De Candolle, ‘ Géograph.
61 ‘Gard, Chronicle,’ 1862, p. 235. Bot., p. 882.
6 Gallesio, ‘Teoria della Ripro- 6 *Ch, Darwin’s Lehre von det
duzione Veg., 1816, p. 125; and Entstehung, &c., 1862, s. 87. ;
‘ Traité du Citrus, 1811, p. 359. 6 Decaisne, quoted in ‘Gard. Chro

63 «Essai sur VHist. des Orangers,’ nicle,’ 1865, p, 271. |

Cuap, XXIy,

nnd it

Ang
i!

CHaP, XXIV, ACCLIMATISATION, 309

“ Noisettes.” In New York the “Irish yew is quite hardy, but the com-

“ mon yew is liable to be cut down.” I may add that there are varieties

of the sweet potato (Convolvulus batatas) which are suited for warmer,
as well as for colder, climates.®7

The plants as yet mentioned have 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 to-
gether and equally exposed, it was observed,® after the unusually
severe winter of 1860-61, that, “in the midst of the dying,
“numerous individuals remained on which the frost had abso-
“lutely made no kind of impression.” Dr. Lindley, after
alluding to this and other similar cases, remarks, “ Among
“the lessons which the late formidable winter has taught us,
“js that, even in their power of resisting cold, individuals of
“the same species’of plants are remarkably different.” Near
Salisbury, there was a sharp frost on the night of May 24th,
1836, and all the French beans (Phaseolus vulgaris) in a bed
were killed except about one in thirty, which completely
escaped.” On the same day of the month, but in the year
1864, there was a severe frost in Kent, and two rows of scarlet-
runners (P. multiflorus) 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. 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 con-
stitutional power of resisting frost,

This work is not the proper place to show that wild plants

67 For the magnolia, see Loudon’s yon Siebold, in ‘Gard. Chron.,’ 1855,
‘Gard. Mag.,’ vol. xiii., 1837, p. 21, p. 822,
For camellias and roses, see ‘Gard, ®° The Editor, ‘Gard. Chron., 1861,
Chron., 1860, p. 384. For the yew, p, 239,
‘Journal of Hort.,’ March 3rd, 1863, "? Loudon’s ‘Gard. Mag., vol. xii,
p. 174, For sweet potatoes, see Col. 1836, p. 378.

310 LAWS OF VARIATION.

CuaP, XXIy,

of the same species, naturally growing at different altitudes
or under different latitudes, become to a certain extent accli-
matised, as is proved by the different behaviour of their seed-
lings 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,” states that
seedlings of the Scotch fir (Pinus sylvestris), raised from seed
from the Continent 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 nnsaleable, while the plants from the
“native Scotch pine, under the same treatment, and standing
“ alongside, 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 Loudon” describes a Cornish variety
of the elm which is almost an evergreen, and of which the shoots are
often killed by the autumnal frosts, so that its timber is of little value.
Horticulturists know that some varieties are much more tender than
others: thus all the varieties of the broccoli are more tender than cab-
bages; but there is much difference in this respect in the sub-varicties of
the broccoli; the pink and purple kinds are a little hardier than the white
Cape broccoli, “ but they are not to be depended on after the thermometer
“falls below 24° Fahr.:” the Walcheren broccoli ig less tender than the
Cape, and there are several varieties which will stand much severer cold
than the Walcheren.” Cauliflowers seed more freely in India than cab-
bages.° 'To give one instance with flowers: eleven plants raised from @
hollyhock, called the Queen of the Whites,74 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 warmer 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

Ce rita Eider ee EE SoM ee ne

70 ¢Gardener’s Chron.,’ 1865, p. 699. 73 Dr. Bonavia, ‘ Report of the Agri
1 * Arboretum et Fruticetum,’ vol. Hort. Soe. of Oudh,’ 1866.
lii. p. 1376. 74 «Cottage Gardener,’ 1860, April
” Mr. Robson, in ‘Journal of Horti- 24th, p. 57.
culture,’ 1861, p. 23.

Cirap, XXIV. ACCLIMATISATION. 311

either pliability of organisation or some constitutional difference. The
same individual cherry-tree, when forced, has been observed during succes-
sive years gradually to change its period of vegetation.” Few pelargo-
niums can resist the heat of a stove, but Alba multzjlora will, as a most
skilful gardener asserts, ‘“ stand pine-apple top and bottom heat the whole
“‘ winter, without looking any more drawn than if it had stood in a com-
“mon greenhouse; 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 multiflora pelargonium must
have a widely different constitution from that of most other varieties of this
plant; it would probably withstand even an equatorial climate.

We have seen that according to Labat the vine and wheat require accli-
matisation 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 tempera-
“ture 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 again, “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 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 Darjeeling 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 therefore 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 acclimatisation
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 off-

7 *Gardener’s Chronicle; 1841, p- will also stand stove heat, see ‘Gard.
291. Chronicle,’ 1845, p. 226.

76 Mr. Beaton, in ‘ Cottage Gardener, 77 ‘Gardener’s Chronicle,’ 1841, p.
March 20th, 1860, p. 377. Queen Mab 439.

312 LAWS OF VARIATION,

Cuap, XXTy.

spring necessarily stands in any direct relation with the nature
of the climate inhabited by the parents.

it is certain that hardy and tender varieties of the same Species
appear in the same country. New varieties thus Spontane-
ously arising become fitted to slightly different climates in
two different 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 acclimatisation by man consists simply in the
selection and preservation of new varieties, But without any
direct intention on his part of securing a hardier variety, accli-
matisation may be unconsciously effected by merely raising
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 con-
stitution, it is possible that mere habit may have done nothing

On the contrary,

towards their acclimatisation. On the other hand, when we

Cuap, XXIV, ACCLIMATISATION. $18

hear that Merino sheep, bred during no great number of genera-
tions 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"* that the races of
melons, squashes, and gourds, which have long been cultivated
in Northern Europe, are comparatively more precocious, and
need much less heat for maturing their fruit, than the varieties
of the same species recently brought from tropical regions. In
the reciprocal 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, inde-
pendently 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 preservation and cultivation
of the varieties peculiar to each country. During the classical.
period, Columella wrote, “ Vernaculum pecus peregrino longe
“* preestantius est.’

IT am aware that the attempt to acclimatise either animals or
plants has been called a vain chimera. No doubt the attempt
in most cases deserves to be thus called, if made independ-
ently of the production of new varieties endowed with a dif-
ferent constitution. Habit, however much prolonged, rarely
produces any effect on a plant propagated by buds; it ap-
parently acts only through successive seminal generations.

78 Quoted by Asa Gray, in ‘Am, Chinois,’ tom. xi. 1786, p. 60, Columella
Journ. of Sci.,’ 2nd series, Jan, 1865, ig quoted by Carlier, in ‘Journal de

p. 106. Physique,’ tom. xxiv. 1784.
79 For China, see ‘Mémoire sur les

314 ' LAWS OF VARIATION.

Cuap, XXIV,

The laurel,.bay, laurestinus, &c., and the J erusalem ar
which are propagated by cuttings or tubers, are probably now
as tender 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 acclimatisation unless the
hardier individuals are either intentionally or unconsciously
preserved. The kidney-bean has often been advanced as an
instance of a plant which has not become hardier since its first
itroduction into Britain. We hear, however, on excellent
authority,*” 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 apparently shows
some degree of acclimatisation in our English 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 separated 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 hardiness of our 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
answer this question satisfactorily.

On the whole the facts now given show that, though habit
does something towards acclimatisation, yet that the sponta-

neous appearance of constitutionally different individuals is a
far more effective agent. As no single instance has been

recorded, either with animals or plants, of hardier individuals

tichoke,

80 Messrs. Hardy and Son, in ‘ Gard. Chronicle,’ 1856, p. 589.

ee i

SEE seinen eee eT

Cuar, XXIV. ARRESTED DEVELOPMENT AND-RUDIMENTS, 315

having been long and steadily selected, though such selection
is admitted to be indispensable for the improvement of any
other character, it is not surprising that man has done little
in the acclimatisation 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 believe
that rudimentary organs are in many cases the result of disuse. Modifica-
tions of structure from arrested development, so great or so serious as to
deserve to be called monstrosities, are of common occurrence, but, as they
differ much from any normal structure, they require here only a passing
notice. When a part or organ is arrested during its embryonic growth,
a rudiment is generally left. ‘Thus the whole head may be represented by
a soft nipple-like projection, and the limbs by mere papille. These rudi-
ments of limbs are sometimes inherited, as has been observed in a dog.™

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 preserved. 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.”®” In
tailless dogs and cats a stump is left; but I do not know whether it
includes at an early embryonic age rudiments of all the caudal vertebre.
in certain breeds of fowls the comb and wattles are reduced to rudi-
ments; in the Cochin-China breed scarcely more than rudiments of spurs
exist. With polled Suffolk cattle, “rudiments of horns can often be felt
* at an early age;”®3 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 organs. With hornless breeds of cattle
and sheep, another and singular 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,™

81 Tsid. Geoffroy St. Hilaire, ‘ Hist. 83 Youatt on Cattle, 1834, p. 174.

Nat. des Anomalies,’ 1836, tom. ii. pp. 84 * Encyclop. Méthod.,’ 1820, p. 483 :
210, 223, 224, 395; ‘Philosoph. Trans- see p. 500, on the Indian zebu casting
act.,” 1775, p. 313. its horns. Similar cases in European

% Pallas, quoted by Youatt on Sheep, cattle were given in the third chapter.
p. 25.

316 LAWS OF VARIATION,

Cuap, XXIy,

the bony protuberances which properly support the horns ex
rudiments,

With cultivated plants it is far from rare to find the petals, Stameng
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.” Tn certain
varieties of the gourd, the tendrils, according to Naudin, are represented
by rudiments or by various monstrous growths. In the broccoli and

ist ag mere

cauliflower the greater number of the flowers are incapable of expansion,

and include rudimentary organs. In the Feather hyacinth (Mascari
comosum) the upper and central flowers are brightly coloured but rudi-
mentary; under cultivation the tendency to abortion travels downwards
and outwards, 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 rudimentary 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 ig
produced. In the Composite, the so-called doubling of the flowers con-
sists in the greater development of the corolla of the central florets,
generally accompanied with some degree of sterility; and it has been
observed ® that the progressive doubling invariably spreads from the cir-
cumference to the centre,—that is, from the ray florets, which so often
include rudimentary organs, to those of the dise. 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.” In these several cases we have a natural 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 showing 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
Compositze, 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 J ussieu,® the abortion is only partial in Carthamus
creticus, but more extended in C. lanatus ; for in this species two or three
alone of the central seeds are furnished with a pappus, the surrounding
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 domestication, when an organ dis-
appears, leaving only a rudiment, the loss has generally been sudden, as
with hornless and tailless breeds ; and such cases may be ranked as inhe-
rited monstrosities. But in some few cases the loss has been gradual, and

*° Pallas, ‘Travels,’ Eng. translat., 87 Lecoq, ‘ De la Fécondation,’ 1862,
Vol. i. p. 243. p. 233.

*° Mr. Beaton, in ‘Journal of Horti- 88 * Annales du Muséum,’ tom. v
culture,’ May 21, 1861, p. 138. p. 319.

aa

Cuap, XXIV. ARRESTED DEVELOPMENT AND RUDIMENTS. S17

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 extremely
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 legs 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 con-
dition; 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 go 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 closely adapted usually
change very slowly. Even if an organ did suddenly 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 final reduction could only be effected by the
slow process of continued disuse or natural selection. Tt 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
inheritance at corresponding periods of life, would go on reducing the
organ;. but as most organs could be of no use at an early embryonic
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 principle, 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 recurrent
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
mammz; but in our domesticated animals, the latter occasionally become
considerably developed and yield milk. The atrophied mamme, 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 developed

318 LAWS OF VARIATION. Cuap. XXIV.

and are furnished with claws. In the common Hen, the spurs and comb
are rudimentary, but in certain breeds these become, independently of
age or disease of the ovaria, well developed. The stallion has canine teeth,
but the mare has only traces of the alveoli, which, as I am informed by
the eminent veterinary Mr. G. T. Brown, frequently contain minute irre-
gular nodules of bone. These nodules, however, sometimes become deve-
loped 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.

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 usually 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 corresponding age, aided by the principle of the economy
of growth, all under the control of natural selection, With
domesticated animals, on the other hand, the principle of eco-
nomy is far from coming into action, and their organs, although
often slightly reduced by disuse, are not thus almost obliterated

with mere rudiments left.

Cuap, XXV. CORRELATED VARIABILITY, 319

OAT Ow A ky.

LAWS OF VARIATION, continued — CORRELATED VARIABILITY,

EXPLANATION OF TERM — CORRELATION AS CONNECTED WITH DEVELOPMENT —
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 — BETWEEN THE SKIN AND DERMAL APPENDAGES
—— BETWEEN THE ORGANS OF SIGHT AND HEARING — CORRELATED MODIFICATIONS
IN THE ORGANS OF PLANTS — CORRELATED ‘MONSTROSITIES — CORRELATION BE-
TWEEN THE SKULL AND EARS — SKULL AND OREST OF FEATHERS — SKULL AND
HORNS — CORRELATION OF GROWTH COMPLICATED BY THE ACCUMULATED EFFECTS
OF NATURAL SELECTION — COLOUR AS CORRELATED WITH CONSTITUTIONAL
PECULIARITIES,

Aut 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 animals 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 monstrous without any other part of
the body being affected. But in some cases, when one part
varies, certain other parts always, or nearly always, simulta-
neously vary; they are then subject to the law of correlated
variation. Formerly I used the somewhat vague expression of
correlation of growth, which may be applied to many large classes
of facts. Thus, all the parts of the body are admirably 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 animals certain structures always co-exist; for in-
stance, a peculiar form of stomach with teeth of peculiar form,
and such structures 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

320 LAWS OF VARIATION. Cuar. XXY.

the initial or primary variations of the several parts were in any
way related: slight modifications or individual 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 ornamented with gay colours; and these characters
manifestly stand in some sort of correlation with the male
reproductive 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 attached at any
age to either sex, and afterwards be exclusively 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 reason for supposing that the original
cause of the variation was necessarily connected with the repro-
ductive 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 differs 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 simul-
taneously produced by some distinct cause. Correlated variation
is an important subject for us; for when one part is modified
through continued selection, either by man or under nature,
other parts of the organisation will be unavoidably modified.
From this correlation it apparently follows that, with our domes-
ticated 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 modification |

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.

1 ‘Fist. des Anomalies, tom. iii. p. arrangement of the nervous system in
392. Prof. Huxley applies the same the Mollusca, in his great paper on the
principle in accounting for the remark- © Morphology of the Cephalous Mollusca,
able, though normal, differences in the in ‘ Phil, Transact.,’ 183, p. 06.

Cuap. XXV. CORRELATED VARIABILITY. 391

in the animal kingdom ; and Mogquin-Tandon ? 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 accompanied 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
developed molar teeth. It is probable that certain modifications
in the larvee of insects would affect the structure 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
extraordinary course of change, whilst other and closely allied
members arrive at maturity with little change of structure.
Another simple case of correlation is that with the increased
or decreased dimensions of the whole body, or of any particular
‘part, certain organs are increased or diminished in number,
or are otherwise modified. Thus pigeon-fanciers have gone on
selecting pouters for length of body, and we have seen that their
vertebre are generally increased 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 number. Fantails have been selected for their large widely-
expanded tails, with numerous tail-feathers, and the caudal
vertebree 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 scutelle 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 erowth of the body
and the period of reproduction ; and, in correspondence with
this, the teeth are now developed earlier than formerly, so that,

* *Eléments de Tératologie Veg.,’ 1841, p, 118.
VOL. II. is

322 LAWS OF VARIATION. Cuap, XXV.

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.’

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 parts are identical in form
and structure during an early period of embryonic development,
and are 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 horn, or
with many-horned sheep which sometimes carry an additional
horn on one side of their heads. With flowers 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 varieties of the Antirrhinum or snapdragon, or that
variety of the kidney-bean (Phaseolus multzflorus) which has a
white standard-petal.

In the vertebrata the front and hind limbs are homologous,
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 Geoffroy * has remarked on the ten-
dency 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 ® that, when the muscles of the arm depart
in number or arrangement from their proper type, they almost
always imitate those of the leg; and so conversely the varying
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 trum-
peter 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

3 Prof. J. B. Simonds, on the Age of 4 ¢ Hist. des Anomalies,’ tom. i. p. 674,
the Ox, Sheep, &c., quoted in ‘Gard, 5 Quoted by Isid. Geoffroy, idem,
Chronicle,’ 1854, p. 588. tom. i, p. 639.

CHAP, XXV, CORRELATED VARIABILITY. 323

according to the excellent authority of Mr. Hewitt,’ been seen
to exceed the wing-feathers in length, and in one case were
actually nine and a half inches in length! Ag Mr. Blyth has
remarked to me, these leg-feathers resemble the primary wing-
feathers, and are totally unlike the fine down which naturally
grows on the legs of some birds, such as grouse and owls. Hence
it may be suspected that excess of food has first given redun-
dancy 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 correspond
with our third and fourth toes. Now, 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 “ bastard-
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 ex-
terior surface support a row of long feathers, like wing-feathers,
but the very same digits which in the wing are completely 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 connection of feathered legs and
membrane between the two outer toes.

Andrew Knight’ has remarked that the face or head and the
limbs vary together in general proportions. Compare, 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 ex-
plained, seems the most probable is, that disuse in all cases tends

6 «The Poultry Book,’ by W. B. Tegetmeier, 1866, p. 250.

y 2

7 A. Walker on Intermarriage, 1838, p. 160.

9

324 LAWS OF VARIATION. Cuap, XXV,

to diminish the feet, the beak becoming at 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 increased in size.

With the increased length of the beak in pigeons, not only
the tongue increases in length, but likewise the orifice of the
nostrils. But the increased length of the orifice 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 be-
tween 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 hereafter
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 homologous 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 com-
petent judges dispute 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 generations. Now, with
the increased size and changed direction of the ears, not only
has the bony auditory meatus 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 me a curious instance of correlation, between hard

8 «The Farrier and Naturalist,’ vol. i., 1828, p. 456.

CHap, XXV, CORRELATED VARIABILITY. 325

“Uety, bones and organs so soft and flexible, as well as so unimportant
Udins under a physiological point of view, as the external ears. The

result no doubt is largely due to mere mechanical action, that. .
“Onl i 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 ege,—that is, with the
mucous membrane which secretes the shell. The colour of
otten the skin and hair, and the odour emitted by the glands of the
| tan skin, are said® to be connected, even in the same race of men.
; and 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
afte fowls and pigeons. In the common cock the feathers on the neck
mo | and loins are always 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 feathers
vad in the male always assume the form of hackles. The wing and
tail-feathers, though arising from parts not homologous, vary
in length together; so that long or short-winged pigeons generally
have long or short tails. The case of the J acobin-pigeon is
se more curious, for the wing and tail feathers are remarkably
long; and this apparently has arisen in correlation with the
elongated and reversed feathers on the back of the neck, which
os form the hood. :

The hoofs and hair are homologous appendages; and a careful
observer, namely Azara,” states that in Paraguay horses of various

ET eT

jee colours are often born with their hair curled and twisted like that
"7 on the head of a negro. This peculiarity is strongly inherited.
the But what is remarkable is that the hoofs of these horses “are

‘absolutely like those of amule.” he hair also of the mane and
tail is invariably much shorter than usual, being only from four

* Godron, ‘Sur l’Espice,’ tom. ii. p. 217.
° *Quadrupédes du Paraguay,’ tom. ii. p, 333.

526 LAWS OF VARIATION, CHAP. XXV.

to twelve inches in length; go 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 “ 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 analogous facts have been
given, that the parent of the Mauchamp breed, so famous for
its fleece, had peculiarly shaped horns. The inhabitants of
Angora assert’ 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
hair or wool and the horns vary in a correlated manner. Those
who have tried hydropathy are aware that the frequent appli-
cation of cold water stimulates the skin ; and whatever stimu-
lates 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, Professor Low ™ ig convinced that with the different races
of British cattle thick 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 correlation on the skull.

With respect to hair and teeth, Mr. Yarrell” found many of
the teeth deficient in three hairless “Atgyptian”’ dogs, and in a
hairless terrier. The incisors, canines, and premolars suffered
most, but in one case all the teeth, except the large tuber-
cular molar on each side, were deficient. With man several
striking cases have been recorded " of inherited baldness with in-

On Sheep, p. 142. British Islands,’ pp. 307, 368.
” ‘Ueber Racen, Kreuzungen, &c.,’ 18 “Proceedings Zoolog. Soc.,’ 1833,
1825, s. 24, p. 1138.

3 Quoted from Conolly, in ‘The 16 Sedewick, ‘Brit. and Foreign
Indian Field,’ Feb, 1859, vol. ii. p. 266. | Medico-Chirurg. Review,’ April, 1863,
‘Domesticated Animals of the p. 453.

b
i
|
|
1

‘CHaPp, XXV. CORRELATED VARIABILITY. 327

herited deficiency, either complete or partial, of the teeth. We see
the same connection 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 remarked in a former part of
this volume that the great reduction 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 reappearance 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 not strictly
connected with our present point, that an agriculturist asserts
that “pigs with little hair on their bodies are most liable to
“ lose their tails, showing a weakness of the tegumental structure.
“Tt may be prevented 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 at the
Burmese Court a man, thirty years old, with his whole body,
except the hands and feet, covered 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” 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

W ‘Gard. Chronicle,’ 1849, p. 205.
18 « Embassy to the Court of Ava,’ vol. i. p. 320.
19.¢ Narrative of a Mission to the Court of Ava in 1859,’ p. 94.

328 LAWS OF VARIATION. Cuar, XXV,

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 dentist: Julia
Pastrana, a Spanish dancer, was a remarkably fine woman, but
she had a thick masculine beard and a 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 irregular double set of teeth, one row being placed
within the other, of which Dr. Purland took a cast. From the
redundancy 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 mam-
mals—namely, the Edentata and Cetacea—which are the most
abnormal in their dermal covering, are likewise the most ab-
normal either by deficiency or redundancy of teeth.

The organs of sight and hearing are generally admitted to be
homologous, both with each other and with the various dermal ap-
pendages ; hence these parts are liable to be abnormally affected
im conjunction. Mr. White Cowper says “that in all cases of
“double microphthalmia brought under his notice he has at the

that out of 241 deaf-mutes in Berlin, no less than fourteen
suffered from the rare disease called pigmentary retinitis, Mr.
White Cowper and Dr. Earle have remarked that inability
to distinguish different colours, or colour-blindness, “is often

“associated with a corresponding inability to distinguish
“ musical sounds.” °

20 These statements are taken from pp. 455 and 458. Liebreich is quoted
Mr. Sedgwick, in the ‘ Medico-Chirurg. by Professor Devay, in his ‘Mariages
Review,’ July 1861, p. 198; April 1863, Consanguins,’ 1862, p, 116.

Guar. XXV. CORRELATED VARIABILITY. 329

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 published 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 pro-
“duced at one and the same birth, such as, like the mother,

“ were entirely white (with blue eyes) were, like her, invariably

“deaf; while those that had the least speck of colour on their
“fur, as invariably possessed the usual faculty of hearing.”

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 com-
“mon colour that was deaf.” In France Dr. Sichel” hag ob-
served during twenty years similar facts; he adds the remark-
able 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 persons as.

marvellous. There is nothing unusual in the relation between
blue eyes and white fur; and we have already 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 made by shouting close to their ears,
for they are, even when asleep, extremely sensitive to a breath
of air, Now, 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 sup-
pose the development of the organs of sight and hearing to be

arrested at the stage of the closed eyelids, the eyes would re--

*! Loudon’s ‘Mag. of Nat. Hist.,’ vol, on the inheritance of deafness in cats,
i, 1829, pp. 66, 178. See also Dr. P. 22 « Annales des Sc. Nat.’ Zoolog., 3rd
Lucas, ‘ L’Héréd, Nat.,’ tom. i. p. 428, series, 1847, tom. viii. p. 239,

330 LAWS OF VARIATION. oa AS, SF

main permanently blue and the ears would be incapable of per-
ceiving sound; and we should thus understand this curious case.
As, however, 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, stamens, and pistils are
all homologous. In double flowers we see that the stamens and
pistils vary in the same manner, 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.
Tn 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 purple flowers, a
purple mark may be seen on the stipules. In other cases the
leaves and fruit and seeds vary together in colour, as in a
curious pale-leaved variety of the sycamore, which has recently
been described in France,” 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.** Pomologists can predict
to a certain extent, from the size and appearance of the
leaves of their seedlings, the probable nature of the fruit; for,
as Van Mons remarks,” variations in the leaves are generally
accompanied by some modification in the flower, and con-
sequently 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 remarkable manner. On the
other hand, several varieties of Cucurbita, which haye dwarfed
stems, all produce, as Naudin remarks with surprise, leaves of
the same peculiar shape. Mr. G. Maw informs me that all the
varieties of the scarlet Pelargoniums which have contracted or
imperfect leaves have contracted flowers: the difference between

23 ‘Gardener’s Chron.,’ 1864, p. 1202. =
24 Verlot gives several other instances, ‘ Des Variétés,’ 1865, p. 72.
25 ¢ Arbres Fruitiers, 1836, tom, il. pp. 204, 226,

Cuap, XXV. CORRELATED VARIABILITY. 331

« Brilliant ” and its parent “Tom Thumb ” is a good instance of
this. It may be suspected that the curious case described by
Risso,” of a variety of the Orange which produces on the young
shoots rounded 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
undergoes 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,” “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 extent 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 been observed
with several varieties,” 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 treated of
cases in which we can partly understand the bond of connexion ;
but I will now give cases in which we cannot even conjecture, or
can only very obscurely see, what is the nature of the bond.
Isidore Geoffroy St. Hilaire, in his work on Monstrosities, in-
sists, “que certaines anomalies coexistent rarement entyr’elles,
“dautres fréquemment, d’autres enfin presque constamment,
“maleré la difference tres-grande de leur nature, et quoiqu’elles
“puissent paraitre completement indépendantes les unes des
“autres.” We see something analogous in certain diseases:
thus I hear from Mr. Paget that in a rare affection of the

26 ¢ Annales du Muséum,’ tom. xx. p. °9 « Hist. des Anomalies, tom. iii. p.
188. 402, See also M. Camille Dareste,
27 ¢Gardener’s Chron. 1843, p. 877. “Recherches sur les Conditions,’ &c.,
°8 Thid., 1845, p. 102. 1863, pp. 16, 48.

332 LAWS OF VARIATION, Cuap, XXV.

renal capsules (of which the functions are unknown), the skin
becomes bronzed; and in hereditary syphilis, both the milk and
the second teeth assume a peculiar 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 colours when first
born are clothed with plenty of down? White Pea-fowls, as has
been observed both in England and France,” 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 accompanied 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 from their short foreheads, upturned
muzzles, and curved lower jaws. In the skull the nasal and pre-
maxillary 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
shortening of the nasal and adjoining bones is the proximate
cause of the other modifications in the skull, including the
upward curvature of the lower jaw, though we cannot 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 touching any bone. That
this deficiency of bone is in some way connected with the tuft
of feathers is clear from tufted ducks and geese likewise having

*° Rey. E. 8. Dixon, ‘Ornamental Poultry,’ 1848, p. 111; Isidore Geoffroy,
‘ Hist. Anomalies,’ tom. i, p. 211.

SS

Cay. XXV. CORRELATED VARIABILITY, 3338

‘perforated skulls. The case would probably be considered by

some authors as one of balancement or compensation. In the

‘ss 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 protuberant until it acquired its present ex-
traordinary structure. Through correlation with the protu-
berance of the skull, the shape and even the relative connexion
of the premaxillary and 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 direction 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 mar-
vellous manner. }

» After this case of the Polish fowl it would be superfluous 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 con-
nexion with the size of the skull, and with the shape of the
frontal bones; thus Cline* 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.” 22

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 inextricably 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

*! “On the Breeding of Domestic Animals,’ 1829, p. 6.
* Youatt on Cattle, 1834, p, 283,

334 LAWS OF VARIATION. Cuap, XXV,

changes of structure would have been indispensable,—namely,
a thickened skull to carry the horns; strengthened cervical
vertebrae, with strengthened ligaments; enlarged dorsal verte-
bree to support the neck, with powerful fore-legs and feet; all
these parts being supplied with proper muscles, blood-vessels,
and nerves. How then could these admirably co-ordinated
modifications of structure have been acquired? 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 conquering 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 favourable 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 excel-
lently 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 excellence ; if we could view the
whole series of intermediate forms between one of these animals
and an early unimproved progenitor, we should behold a vast
number of animals, not equally improved in each generation
throughout their entire structure, but sometimes a little more
in one point, and sometimes in another, yet on the whole gradu-
ally 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 tend to give to the

33 Mr, Herbert Spencer (‘Principles remarks: ‘‘We have seen reason to
of Biology,’ 1864, vol. i. pp. 452, 468) “‘ think that, as fast as essential faculties

takes a different view; andin one place ‘‘ multiply, and as fast as the number of

Cuap, XXV. CORRELATED VARIABILITY, 335

male elk its present structure, yet it is probable that the inhe-
rited 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 analogy,
tend from the first to vary in a correlated manner. 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 ig probable that the
horns and skull would immediately act on each other through
the principle of correlation. Lastly, the growth and subse-
quent 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 require
increased powers of mastication, digestion, respiration, and
excretion.

Colour as Correlated with 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.* Thus Dr.
Beddoe by his tables shows® that a relation exists between
liability to consumption and the colour of the hair, eyes, and
skin. It has been affirmed * that, in the French army which
invaded Russia, soldiers having a dark complexion, from the

“organs that co-operate in any given
“function increases, indirect equilibra-
“tion through natural selection becomes
‘less and less capable of producing spe-
“cific adaptations; and remains fully
‘capable only of maintaining the gene-
“ral fitness of constitution to conditions,”
This view that natural selection can do
little in modifying the higher animals
surprises me, seeing that man’s selec-

tion has undoubtedly effected much
with our domesticated quadrupeds and
birds,

34 Dr. Prosper Lucas apparently dig-
believes in any such connexion, ‘ L’Héréd,
Nat.’ tom. ii. pp. 88-94.

* ‘British Medical Journal,’ 1862, p.

33.

°° Boudin, ‘Géograph. Médicale,’
tom, i. p, 406.

336 LAWS OF VARIATION, CHAP, XXV,

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 varieties
are not thus favoured, we must believe in the existence 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 coloured varieties.
Dark-coloured pelargoniums and verbenas are more scorched by
the sun than varieties of other colours. Red wheats are believed
to be hardier than white; whilst red-flowered hyacinths were
more injured during one particular winter in Holland than other
coloured varieties. With animals, white terriers suffer most
from the distemper, white chickens from a parasitic worm in
their trachez, 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 producing yellow silk.

The cases of immunity from the action of certain vegetable
poisons, in connexion with colour, are more interesting, and are
at present wholly inexplicable. T have already given a remark-
able instance, on the authority of Professor Wyman, of all the
hogs, excepting those of a black colour, suffering severely
in Virginia from eating the root of the Lachnanthes tinctoria.

5

Cuap, XXV. CORRELATED VARIABILITY, 337

According to Spinola and others,” buckwheat (Polygonum fago-
pyrum), 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 Ay-
pericum 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 poisonous only when it growns
in swamps; nor is this improbable, as we know how readily the
poisonous principle in plants is influenced by the conditions
under which they grow. :

Three accounts have been published in Eastern Prussia,
of white and white-spotted horses being greatly injured by
eating mildewed and honeydewed vetches; every spot of skin
bearing white hairs becoming inflamed and gangrenous. The
Rey. 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
probably mildewed ; the horses, with two exceptions, were ches-
nuts 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 (dthusa
cynapium) they are sometimes 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.”* With cattle, independently of the action of
any poison, cases have been published by Youatt and Erdt
of cutaneous diseases with much constitutional disturbance (in
one instance after exposure to a hot sun) affecting every single
point which bore a white hair, but completely passing over
other, parts of the body. Similar cases haye been observed
with horses.”

We thus see that not only do those parts of the skin which
bear white hair differ in a remarkable manner from those bearing

37 This fact and the following cases 38 Mr. Mogford, in the ‘ Veterinarian,’
when not stated to the contrary, are quoted in ‘ The Field, Jan. 22, 1861, p.
taken from a very curious paper by 545,

Prof. Heusinger, in ‘ Wochenschrift fiir 89 «Edinburgh Veterinary Journal,’
Heilkunde,’ May, 1846, s. 277. Oct. 1860, p. 347.

VOL. II. z

338 LAWS OF VARIATION, Cuap, XXYV.

hair of any other colour, but that in addition some great con-
stitutional 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.

“ey —$—

Ri ieteetct ae ro

co
Oo
Je)

Cuap, XXVI, AFFINITY OF HOMOLOGOUS PARTS.

CHAPTER XXYVI.

LAWS OF VARIATION, continwed —SUMMARY,

ON THE AFFINITY AND COHESION OF HOMOLOGOUS PARTS — ON THE VARIABILITY 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 CAPSULE, AS INDUCING VARIATION — ANALOGOUS OR
PARALLEL VARIETIES — SUMMARY OF THE THREE LAST CHAPTERS,

On the Affinity of Homologous Parts.—Tuts law was first
generalised by Geoffroy Saint Hilaire, under the expression of
La loi de Vaffinité de soi pour sot. It has been fully discussed and
illustrated by his son, Isidore Geoffroy, with respect to monsters
in the animal kingdom,! 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
contact, they often blend into a single part or organ; and this
complete fusion indicates some mutual affinity between the
parts, otherwise they would simply cohere. Whether any
power exists which tends to bring homologous parts into con-
tact seems more doubtful. The tendency 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 ex-
traordinary than the manner, as shown in various published
plates, in which the Corresponding parts of two embryos become
intimately fused together. This ig 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-

1 « Hist des Anomalies,’ 1832, tom. i. pp. 22, 587-556; tom. iit. p. 462,

22

340 LAWS OF VARIATION, Cuar, XXVI.

faces. Whenever two bodies or two heads are united, each
bone, muscle, vessel, and nerve on the line of junction seems
to seek out its fellow, and becomes completely fused with it.
Lereboullet,” 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
corresponding parts of each head grow into one during the
further progress of development, accompanied as it always is
with incessant absorption and renovation. Double monsters
were formerly thought to be formed by the union of two
originally distinct embryos developed upon distinct vitelli; but
now it is admitted that “their production is due to the sponta-
“neous divarication of the embryonic mass into two halves ;’?
this, however, is effected by different methods. But the belief
that double monsters originate from the division of one germ,
does not necessarily affect the question of subsequent fusion, or
render less true the law of the affinity of homologous parts.

The cautious and sagacious J. Miiller,{ when speaking of
Janus-like monsters, says that “ without the supposition 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 con-
clusion, and argues from the existence of a whole series of mon-
strosities, graduating from a perfectly double monster to a mere
rudiment of an additional digit, that “an excess of formative
“power” is the cause and origin of every monstrous 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 embryo, 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.

* “Comptes Rendus,’ 1855, pp. 855, * ‘Elements of Physiology,’ Eng.
1029, translat., vol. i, 1838, p. 412. With
* Carpenter’s ‘Comp. Phys.,’ 1854, respect to Vrolik, see Todd’s ‘Cyclop. of
p. 480; see also Camille Dareste, Anat. and Phys.,” vol. iv., 1849-52,
‘Comptes Rendus,’ March 20th, 1865, p. 973.

p. 562,

Cuap, XXVI. AFFINITY OF HOMOLOGOUS PARTS. o41

Hunter and others have observed lizards with their tails repro-
duced and doubled. When Bonnet divided longitudinally the
foot of the salamander, several additional digits were occasionally
formed. But neither 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 become 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 applies to
the homologous organs of the same individual animal, as well as
to double monsters. Isidore Geoffroy gives a number of in-
stances of two or more digits, of two whole legs, of two kidneys,
and of several teeth becoming 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.
As Geoffroy remarks, these facts illustrate in an admirable
manner the normal fusion of various organs which during an
early embryonic period are double, but which afterwards always
unite into a single median organ. Organs of this nature are
generally found in a permanently double condition in other
members of the same class. These cases of normal fusion
appear to me to afford the strongest support in favour of the
present law. Adjoining parts which are not homologous some-
times cohere; but this cohesion appears to result from mere
juxtaposition, and not from mutual affinity.

In the vegetable kingdom Mogquin-Tandon® gives a long
list of cases, showing how frequently homologous parts, such
as leaves, petals, stamens, and pistils, as well as ageregates 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 proper number of sepals, petals, stamens and pistils,
with each whorl of organs circular, and with no trace left of the

> ‘ Tératologie Vég.,’ 1841, livre iii,

342 LAWS OF VARIATION. Cuap, XXVL

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 multitude of cases, both in
the animal and vegetable kingdoms; it throws a clear light on
many normal structures which have evidently been formed by
the union of originally 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 Geoffroy® 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, be considered as fully
established; but the evidence is chiefly derived from organic
beings living under their natural conditions, with which we are
not here concerned. When the vertebree, 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 decisive ; but
the fact, as far as it may be trusted, probably depends on mul-
tiple parts being of less physiological importance than single
parts; consequently their perfect standard of structure has been
less rigorously enforced by natural selection.

Compensation of Growth, or Balancement.—This law, as applied

to natural species, was propounded by Goethe and Geoffroy 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 im-
portance has probably been exaggerated. It ig scarcely possible
to distinguish between the supposed effects of such compensation
of growth, and the effects of long-continued selection, which

6 «Hist. des Anomalies,’ tom. iii, pp. 4, 5, 6.

an

Cuap, XXVI. COMPENSATION. 343

may at the same time lead to the augmentation of one part and
the diminution of another. There can be no doubt that an organ
may be greatly increased without any corresponding diminution
in the adjoining 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 existence
does not bear hard on our domesticated productions; conse-
quently the principle of economy of growth will seldom affect
them, and we ought not to expect to find frequent evidence of
compensation. We have, however, some such cases. Moquin-
Tandon describes a monstrous bean,’ in which the stipules were
enormously developed, and the leaflets apparently in conse-
quence completely aborted; this case is interesting, as it repre-
sents the natural condition of Lathyrus aphaca, with its stipules
of great size, and its leaves reduced to mere threads, which act
as tendrils. De Candolle* has remarked that the varieties of
taphanus 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 Brassica
asperifolia. 'The varieties of the potato which produce tubers
very early in the season rarely bear flowers; but Andrew
Knight,’ by checking the growth of the tubers, forced the plants
to flower. The varieties of Cucurbita pepo which produce
large fruit yield, according to Naudin, few in number; whilst
those producing small fruit yield a vast number. Lastly,
I have endeavoured to show in the eighteenth chapter that with
many cultivated plants unnatural treatment 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 becomes 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

[| Vég., p. 156, See also 8 «Mémoires du Muséum,’ &e., tom.
my paper on climbing plants in ‘Jour- viii, p. 178.
Bal Of Tan nly SA oe eee ® Loudon’s ‘ Encyclop. of Gardening,’

p. 114. p. 829.

344 LAWS OF VARIATION. Cuap, XXVI,

fattening well. With fowls which ‘have large topknots and
beards the comb and wattles are generally 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,

Mechanical Pressure as a Cause of Modifications—In some ’

few cases there is reason to believe that mere mechanical
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” 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” believes that this is determined
by the form of the pelvis, which again, no doubt, stands in
close relation 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 impossible to disentangle any
direct result of this kind from that consequent on natural selec-
tion. Godron has argued” 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 difference in the shape
both of the seed and corolla, in the interior and exterior florets
in certain compositious and umbelliferous plants, is due to the

pressure to which the inner florets are subjected; but this con-
clusion is doubtful.

The facts just given do not relate to domesticated produc-
tions, and therefore do not strictly concern us. But here is

& more appropriate case: H. Miiller® has shown that in short-

10 Prichard, ‘Phys. Hist. of Man- 1039,

kind,’ 1851, vol. i. p. 824. 8 Ueber Fotale Rachites, ‘ Wiirz-
Annales des Sc, Nat.,’ Ist series, burger Medicin. Zeitschrift, 1860, B. i.
tom. xix. p. 827. 8. 265.

“Comptes Rendus,’ Dec. 1864, p.

ee eR Te Te RT oN RRR Tee See te oe ear ee

“ ‘

CuaPp, XXVI. RELATIVE POSITION OF PARTS. 345

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 having elongated muzzles; and as
he remarks, any inherited change in the arrangement of the
teeth deserves notice, considering their classificatory import-
ance. This difference in position is due to the shortening of

certain facial bones, and the consequent want of space; and

the shortening results from a peculiar and abnormal state of
the basal cartilages of the bones.

Relative Position of Flowers with 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 development, or
to reversion to a primordial condition. Moquin-Tandon 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 ;* and he adduces, amongst other instances, that of Tewcrium cam-
panulatum. In another Labiate plant grown by me, viz. the Galeobdolon
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’ gives the names of ten
varieties 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 produced 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 colour; the
stamens are graduated 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 cor-
relation between these changes is well shown when one of the two upper
petals alone loses its dark mark, for in this case the nectary does not
entirely abort, but is usually much reduced in length. *®

MM < Tératologie Vég., p. 192. Dr. M. 2nd, 1861, p. 253.
Masters informs me that he doubts the 16 It would be worth trial to fertilise
truth of this conclusion; but the facts with the same pollen the central and
to be given seems to be sufficient to es- —_ lateral flowers of the pelargonium, and
tablish it. of some other highly cultivated plants,
* ‘Journal of Horticulture, July protecting them of course from insects ;

ini eS te ee eres) ee cies soe eet ee Tit. oe eft ait

|

546 LAWS OF VARIATION, Cuar, XXVL

laria, nearly four inches in length, which was almost completely peloric ;
it grew on the summit of the plant, with a normal flower on each side;
Prof. Westwood also has described ® three similar peloric flowers, which all
occupied a central position on the flower-branches. In the Orchideous
genus, Phalnopsis, 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 papilionaceous 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 strize like those on the standard-petal. The keel seemed
to resist the change more than the other petals. Dutrochet has described

an exactly similar case in France, and I believe these are the only two

some manner related. Dr. Masters has briefly described another legumi-
nous plant,” 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
Naudin remarks, not rarely occur on the same plant, but in this case the
spurred form almost invariably stands on the summit of the spike.

The tendency in the terminal or central flower to become peloric more fre-
quently than other flowers, probably results from “the bud which stands
“on the end of a shoot receiving the most sap; it grows out into a stronger
“shoot than those situated lower down.” Ihave discussed the connection
between pelorism and a central position, partly because some few plants
are known normally 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® states that when an
Auricula throws up a side bloom it is pretty sure to keep its character ;
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

then to sow the seed separately, and 20 ¢ Journal of Horticulture,’ July
observe whether the one or the other 23, 1861, p. 311.

lot of seedlings varied the most. 71 « Nouvelles Archives du Muséum,
17 Quoted in ‘ Journal of Horticulture, — tom. i, p. 137.

Feb. 24, 1863, p. 152. *» Hugo von Mohl, ‘The Vegetable
'8 “Gardener’s Chronicle,’ 1866, p. Cell” Eng. tr., 1852, p. 76.

612. For the Phalaenopsis, see idem, > The Rev. H. H. Dombrain, in
1867, p. 211. ‘Journal of Horticulture,’ 1861, June

9 Mémoires . . des Végétaux, 1837, 4th, p. 174; and June 25th, p. 234;
tom. ii. p. 170. ~ —- 1862, April 29th, p. 83.

aoe,

Cuap, XXVI. RELATIVE POSITION OF PARTS. 347

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, 1 do not know. Mr.
Dombrain insists that, whatever may be the commonest kind of imper-
fection 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 ten-
dency 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 another flower. Now Dr. Masters™ states that
the central or uppermost flower on a plant is generally the most liable to
prolification. Thus, in the varieties of the Auricula, the loss of their
proper character and a tendency to prolification, and in other plants a ten-
dency to prolification and pelorism, are all connected together, and are due
either to arrested development, or to reversion to a former condition.

The following is a more interesting case; Metzger” cultivated in Ger-
many 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 states that in the first genera-
tion, 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 we 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 position 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 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 fre-
“ quently much smaller than the rest; and if these small peas are care-
“fully 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. Chaté” says that in raising seedling stocks he succeeds
in getting 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 separated and

24 ¢Transact. Linn. Soce.,’ vol. xxiii. *6 <Gardener’s Chronicle’ 1850, p-
1861, p. 360. 198. ;

25 « Die Getreidearten,’ 1843, s. 208, *7 Quoted in ‘Gardener’s Chron.,’
209. 1866, p. 74.

348 LAWS OF VARIATION. Cuar, XXVI.

“ 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 connection 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 appear-
ance 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 varia-
tion, but with the results; but this discussion could not have
been more conveniently introduced elsewhere. The cases of
analogous 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 constitution, and which consequently
vary in an analogous manner; 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 varieties; and as Bernhardi
has remarked,” a multitude of plants, as distinct as possible, have yielded
varieties with deeply-cut or laciniated leaves. Varieties descended from
three distinct species of Brassica have their stems, or so-called roots, en-
larged into globular masses. The nectarine is the offspring of the peach;
and the varieties of both these trees. offer a remarkable parallelism in the
fruit being white, red, or yellow fleshed—in being clingstones or free-
stones—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

SE SES CR A Ee
*8 ‘Ueber den Begriff der Pflanzenart,’ 1834, s. 14.

i

CuaP, XXVI. ANALOGOUS VARIATION, 349

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 cor-
respond so closely in character that, as Naudin insists, they may be ar-
ranged 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 allied genera; thus, one variety has fruit so like,
both externally and internally, 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 portions of the pulp; in another the fruit, when ripe, suddenly
cracks and falls into pieces; and all these highly remarkable peculia-
rities are characteristic of species -belonging to allied genera. We can
hardly account for the appearance of so many unusual 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, independently
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; 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
remarked*® 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 semi-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-varicties occa-
sionally appear coloured exactly like the parent rock-pigeon, with black
wing-bars, white loins, banded tail, &e.; and no one can doubt that these
characters are simply due to reversion. So with minor details; turbits
properly have white tails, but occasionally a bird is born with a dark-
coloured and banded tail; pouters 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
appearing from reversion. In some domestic varieties the Wwing-bars,
instead of being simply black, as in the rock-pigeon, are beautifully
edged with different zones of colour, and they then present a striking
analogy with the wing-bars in certain natural species of the same family,
such as Phaps chalcoptera; and this may probably be accounted for by

Sele ee ee RN

29 * Domesticated Animals,’ 1845, p. 351.

359 LAWS OF VARIATION. Cuap, XXVI.

all the forms descended from the same remote progenitor having a ten-
dency to vary in the same manner. Thus also we can perhaps understand
the fact of some Laugher-pigeons cooing almost like turtle-doves, and
of several races having peculiarities in their flight, 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,
resembles some other race; thus certain runts tremble and slightly elevate
their tails, like fantails; and turbits inflate the upper part of their ceso-
phagus, like pouter-pigeons. —

It is a common circumstance to find certain coloured marks persistently
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 we have seen, are elegantly zoned with different
tints. The Spot pigeon is characterised by the whole plumage being white,
excepting 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 variation, for the tail is
white, except the outer edges of the outer feathers, which are black.%

With some species of birds, for instance with gulls, certain coloured parts
appear as if almost washed out, and I have observed exactly the same
appearance in the terminal dark tail-bar in certain pigeons, and in the
whole plumage of certain varieties of the duck. Analogous facts in the
vegetable kingdom could be given.

Many sub-varieties of the pigeon have reversed and somewhat lengthened
feathers on the back part of their heads, and this ig certainly not due to
reversion to the parent-species, which shows no trace of such structure ;
but when we remember that sub-varieties of the fowl, turkey, canary-
bird, duck, and goose, all have topknots 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 progenitor of this species
may have been spangled, and a still earlier or a later progenitor may
have been pencilled. But as many gallinaceous birds are spangled or
pencilled, it is a more 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 account for the ewes in certain breeds of sheep being
hornless, like the females of some other hollow-horned ruminants; it may
account for certain domestic cats having slightly-tufted ears, like those of
the lynx; and for the skulls of domestic rabbits often differing from each

*° Bechstein, ‘Naturgeschichte Deutschlands,’ Band iv., 179%, s. 31.

Cuap, XXVI. ANALOGOUS VARIATION. "351

other in the same characters by which the skulls of the various species of
g s differ.

a aac ae 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 domestic
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 for-
merly given, to believe that they reappear from direct reversion to the
wild parent-horse. But when horses have two 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 unstriped species
often leads to the hybrid offspring being conspicuously striped—bearing
also in mind that the act of crossing certainly 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 progenitor of the whole genus.

IT have discussed this subject of analogous variation at consi-
derable 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 harmony with the fore-
going cases, and explicable only on the theory of descent.
Secondly, because these facts are important from showing, as
remarked in a former chapter, that each trifling variation is
governed by law, and is 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, because these facts are to a certain extent related to a
more general law, namely, that which Mr. B. D. Walsh®* has
called the “Law of Eguable Variability,” or, as he explains 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
“ oiven 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 Selec-
tion, in which it was shown that with domestic races, which are

31 * Proc, Entomolog

- Soc. of Philadelphia,’ Oct, 1863, p. 213.

352 LAWS OF VARIATION, Cuap, XXVI.

now undergoing rapid improvement, those parts or characters
which are the most valued vary the most. ‘This naturally fol-
lows 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 selection, 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 accordingly are now less variable. This statement makes
@ near approach to Mr. Walsh’s law of Equable Variability.
Secondary sexual characters, it may be added, rarely serve to
characterise distinct genera, for they usually differ much in the
species of the same genus, and are highly variable in the indi-
viduals of the same species; we have also seen in the earlier

chapters of this work how variable secondary sexual characters
become under domestication.

Summary of the three previous Chapters, on the Laws of Variation.

In the twenty-third chapter we have seen that changed con-
ditions occasionally act in a definite manner on the organisation,
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 organisa-
tion or indirectly through the reproductive system being affected
is indefinite and fluctuating variability. In the three latter
chapters we have endeavoured 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. Increased functional activity strengthens
the sense-organs. Increased and intermittent pressure thickens
the epidermis; and a change in the nature of the food some-
times modifies the coats of the stomach, and increases or

Cuap, XXVI. SUMMARY. 353

decreases the length of the intestines. Continued disuse, on
the other hand, weakens and diminishes all parts of the organi-
sation, Animals which during many generations have taken
but little exercise, have their lungs reduced in size, and as a
consequence the bony fabric of the chest, and the whole form of
the body, become modified. 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
scapule, 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 good reason to believe that this has often occurred
under nature. The cause of this difference 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
organisation 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 domesti-
cation, they are the result of a sudden arrest of development,
and not of long-continued disuse with the absorption of all super-
fluous parts; nevertheless they are of interest, as showing that
rudiments are the relics of organs once pertectly 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 consequently 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

VOL, II. ae

”

354 LAWS OF VARIATION. Cnap. XXVI..

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 their early development and are exposed to similar condi-
tions, 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 hearing; 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 wing-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 structure 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 we 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 the
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 peculiarities 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

~ laws, which directly or in

Cuap, XXVI, SUMMARY. 355

certain parts have been greatly modified to serve some useful
purpose; but we almost invariably find that other parts have
likewise been more or less modified, 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 organi-
sation; but from what we have now seen, we may believe that
many modifications are of no direct service, haying 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 are 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 principle 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 structure; but these changes are often due to reversion.
Modifications, in whatever manner caused, will be to a certain
extent regulated by that co-ordinating power or nisus Sormativus,
which is in fact a remnant
displayed by many lowly organised beings in their power of
fissiparous generation and budding. Finally, the effects of the

largely influenced by man’s selection, and will so far be deter-
mined by natural selection that changes a

me species, or from
are liable to revert to characters

Yad

356 LAWS OF VARIATION. CHAP, XXVI.

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.

Cuar, XXVIIL PROVISIONAL HYPOTHESIS OF PANGENESIS. 357

CHAPTER XXVIII.

PROVISIONAL HYPOTHESIS OF PANGENESIS.

PRELIMINARY REMARKS, — FIRST PART :— 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 NECESSARY ASSUMP-
TIONS ARE IMPROBABLE — EXPLANATION BY AID OF THE HYPOTHESIS OF THE
SEVERAL CLASSES OF FACTS SPECIFIED IN THE FIRST PART—CONCLUSION,

In the previous chapters large classes of facts, such as those bear-
ing on bud-variation, the various forms of inheritance, 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
wish to explain to himself, even in an imperfect manner, how it
is possible for a character possessed by some remote 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 it comes that organic beings
identical in every respect are habitually produced by such
widely different processes, as budding and true seminal genera-
tion. [am aware that my view is merely a provisional hypo-
thesis or speculation; but until a better one be advanced, it
may be serviceable by bringing together a multitude of facts
which are at present left disconnected by any efficient cause.
As Whewell, the historian of the inductive sciences, remarks :—
“Hypotheses 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 advance the hypothesis of

358 Cuap, XXVII.

- PROVISIONAL HYPOTHESIS

Pangenesis, which implies that the whole organisation, in the
sense of eVery separate atom or unit, reproduces itself. Hence
ovules and pollen-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 dispropor-
tionate length. In the Second Part the hypothesis will be given;
and we shall see, -after considering how far the necessary
assumptions are in themselves 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.! It is probable that
segmentation could be carried much further in some 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 processes are essentially alike.’
Prof. Huxley remarks, “fission is little more than a peculiar
“mode of budding,” and Prof. H. J. Clark, who has especially

1 Quoted by Paget, ‘Lectures on
Pathology,’ 1853, p. 159.

2 Dr. Lachmann, also, observes
(‘Annals and Mag. of Nat. History,’
2nd series, vol. xix., 1857, p. 2381)
with respect to infusoria, that “ fissa-
“tion and gemmation pass into each
“other almost imperceptibly.” Again,
Mr. W. ©. Minor (‘ Annals and Mag. of
Nat. Hist.,’ 8rd_ series, vol. xi. p. 328)

Shows that with Annelids the distinc-
tion that has been made between fission
and budding is not a fundamental one.
See Bonnet, ‘ uvres d’ Hist. Nat.,’ tom.
V.. 1781, p. 339, for remarks on the
budding-out of the amputated limbs
of Salamanders. See, also, Professor
Clark’s work ‘Mind in Nature,’ New
York, 1865, pp. 62, 94.

‘Cuar, XXVIL a OF PANGENESIS. 359

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 papilla, which is
first formed, consists of undeveloped cellular tissue like that
forming an ordinary bud, the expression 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.

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 re-
pairs a trifling injury in any part, and the power which pre-
viously “was occupied in its maintenance by the continued
“mutation of its particles,” there cannot be any great difference ;
and we may follow Mr. Paget in believing them to be the self-
same power. As at each stage of growth an amputated part
is replaced by one in the same state of development, we
must likewise follow Mr. Paget in admitting “that the powers
“of development from the embryo are identical with those
“exercised 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 gemmation, 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 elements
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 go ereat as it at first
appears ; for ovules occasionally, and even in some cases fre-

quently, become developed into perfect beings, without the con-

3 Paget, ‘Lectures on Pathology,’ 1853, p, 158. * Idem, pp. 152, 164, _
4 . : ,

360 PROVISIONAL HYPOTHESIS Cuar. XXVIUI..

course of the male element. J. Miiller and others admit that
ovules and buds have the same essential nature; and in the
case of Daphnia Sir J. Lubbock first showed that ova and
pseudova are identical in structure. 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 incap-
able of fertilisation. This is the case with the germ-balls of
the Cecidomyide larva, as described by Leuckart.2 Ovules
and the male element, before they become united, have, like
buds, an independent existence. Both have the power of trans-
mitting every single character possessed by the parent-form.
We see this clearly when hybrids are paired inter se, for the
characters of 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 stronger power of transmission than the
other.

It has been maintained by some authors that a bud differs
essentially from a fertilised germ, by always reproducing the
perfect character of the parent-stock; whilst fertilised germs
become developed into beings which differ, 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 having 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 9
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 arisine from seed.
Although bud-varieties usually retain their character during

° On the Asexual Reproduction of ® See some excellent remarks on this
Cecidomyide Larve, translated in head by Quatrefages, in ‘Annales des
‘Annals and Mag. of Nat. Hist.,’March, Se, Nat.,’ Zoolog., 3rd series, 1850, p.
1866, pp. 167, 171. » 188,

CuaP, XXVII. OF PANGENESIS. 361

successive bud-generations, 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 remarkable
of the several points of agreement between the offspring from
bud and seminal reproduction.

There is, however, one difference between beings produced
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 metamorphoses 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 accompaniment 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 produc-
tion or subsequently to it, they often advance in organisation,
as we see in the many cases of “alternate generation.” In thus
speaking of alternate 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, however, such
as mosses and certain alge, according to Dr. L. Radlkofer,’? when
propagated asexually, do undergo a retrogressive metamorphosis.
We can to a certain extent understand, as far as the final cause
is concerned, why beings propagated by buds should so rarely
retrogress during development; for with each organism the
structure acquired at each stage of development must be adapted
to its peculiar habits. Now, with beings produced by gemmation,
—and this, differently from sexual reproduction, may occur at
any 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.

7 “Annals and Mag, of Nat, Hist,’ 2nd series, vol. xx., 1857, pp. 153-455.

362 PROVISIONAL HYPOTHESIS Cuap, XXVIL

From the several foregoing considerations we may conclude
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 agreement between gemmation,
fissiparous generation, the repair of injuries, and ordinary growth
or development. The capacity of fertilisation by the male
element seems to be 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, however, indicate two important
advantages gained by the concourse of the two sexes, or rather
of two individuals belonging to opposite sexes; for, as I haye
shown in a former chapter, the structure of every organism
appears to be especially adapted for the concurrence, at least
occasionally, of two individuals. In nearly the same manner
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 inter-
crossing of the varying individuals will tend to keep each form
fitted for its proper place in nature; and crossing can be effected
only by sexual generation, but whether the end thus gained
is of sufficient importance to account for the first origin of
sexual intercourse 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 creature,
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-extended 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 effects of close interbreeding when long

Cuap, XXVII. OF PANGENESIS. 363

continued, to believe that the advantage thus gained is very
great. Besides 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 spermatheca of a female insect, like-
wise 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 cer-
tainly they do not in ordinary cases differ in their power of
giving character to the embryo. This view of the importance
of the quantity of formative matter seems probable 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,’ 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
Newport,’ who adds the important fact, established by numerous
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 development, namely, the partial
segmentation of the yelk, does occur to a greater or less extent,
but is never completed up to granulation. The rate of the seg-
mentation is likewise determined by the number of the sperma-
tozoa. With respect to plants, nearly the same results were
obtained by Kélreuter and Gartner. This last careful observer
found,’® after making successive trials on a Malva with more
and more pollen-grains, that even thirty grains did not fer-
tilise a single seed; but when forty grains were applied to the

8 ‘ Annales des Sc. Nat., 3rd series, 1850, tom. xiii.

9 «Transact. Phil. Soc., 1851, pp. 196, 208, 210; 1853, p. 245, 247.
10 « Beitrage zur Kenntniss,’ &c., 1844, s, 345,

364 PROVISIONAL HYPOTHESIS Cuar, XXVIL

stigma, a few seeds of small size were formed. The pollen-
grains of Mirabilis are extraordinarily large, and the ovarium
contains only a single ovule; and_ these circumstances led
Naudin™ to make the following 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 pecu-
liar formative matter which is contained 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 parthe-
nogenesis, that is, when the male element is wholly excluded ;
for M. Jourdan” found that, out of about 58,000 egos laid by
unimpregnated 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 number
produced caterpillars. Therefore it is not an improbable 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 is the function of the spermatozoa to commu-
nicate life to the ovule seems a strange one, seeing that the
unimpregnated ovule is already alive and continues for a con-
siderable 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 chapter the
curious case of the Cytisus adami, it was shown that, after the tissues

1 ¢Nouvelles Archives du Muséum,’ 22 As quoted by Sir J. Lubbock in
tom. i, p. 27. ‘ Nat. Hist. Review,’ 1862, p. 345.

Cuap, XXVII. OF PANGENESIS., 365

of two plants belonging to distinct species or varieties have become
intimately united, buds are occasionally produced which, like
hybrids, combine the characters of the two united forms. It is
also 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. The possibility of the production
of hybridised buds by the union of two distinct vegetative tissues
is an important fact, as it shows us that sexual and asexual
reproduction are essentially the same; for the power of combin-
ing in the offspring the characters of both parents is the most

striking of all the functions of sexual generation.

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
pollen from the lemon, the fruit bore stripes of perfectly charac-
terised 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 the flower-stalk. These parts in ordinary cases are wholly
formed by the mother-plant. We here see the male element
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 form. 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 mother-plant must be looked at as distinct
individuals.

With animals which do not breed u
of which all the parts are then full
possible that the male element
female. But we have the analog
tained case of the male element of a distinct form

ntil nearly mature, and
y developed, it is hardly
should directly affect. the
ous and perfectly well-ascer-
, a8 with the

366 PROVISIONAL HYPOTHESIS Cuap, XXVIL.

quagga and Lord Morton’s mare, affecting the ovarium of the
female, so that the ovules and offspring subsequently produced
by her when impregnated 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 ereat and sudden,
as with the metamorphoses of most insects. Between these ex-
tremes we have, even within the same class, every gradation :
thus, as Sir. J. Lubbock has shown,!* 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,
or suppressed, in most other insects. In ordinary metamor-
phoses, the parts and organs appear to become changed into the
corresponding parts in the next stage of development; 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
“ individual, perish and are cast off; they are not changed into
“ the corresponding parts of the new individual. These are due
* to a new and distinct developmental process,” &."* Metamor-
phosis, however, graduates so insensibly 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 parts ;
but the eyes of the old and the young animal are developed in
entirely 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

8 “Transact. Linn. Soe.,’ vol. Xxiv., on this subject, in reference to the de-

1863, p. 62. velopment of star-fishes, and shows how
4 * Parthenogenesis, 1849, pp. 25- curiously metamorphosis graduates into

26. Prof. Huxley has some excellent gemmation or zoid-formation, which is

remarks (‘Medical Times,’ 1856, p. 637) in fact the same as metagenesis.

a CE ee sae a Sy AR Na tae ee

le (amor.

Ito the

i ii es

Cuap. XXVII. OF PANGENESIS. 367

may be called metagenesis. The metagenetic process 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.

If, instead of a single individual, several were to be thus
developed metagenetically within a pre-existing form, the pro-
cess would be called one of alternate generation. The young
thus developed may either closely resemble the encasing parent-
form, as with the larve of Cecidomyia, 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 importance
for our present subject. When an organ, the eye for instance,
is metagenetically formed in a part of the body where during
the previous stage of development no eye existed, we must look
at it as a new and independent growth. The absolute independ-
ence 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
alternate 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 inheritance of modifica-
tions at corresponding ages.

We are led to the same conclusion, namely, the independ-
ence 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 extremely 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 larva.
In the same sub-order of crabs, namely, the Macroura, as Fritz

* Prof. J. Reay Greene, in Giinther’s « Record of Zoolog, Lit,’ 1865, p. 625.

368 PROVISIONAL HYPOTHESIS CuaP. XXVII.

Miller 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 Paleemon appears under the
form of a Zoea, and Peneus under the Nauplius-form; and
how wonderfully these larval forms differ from each other, is
known to every naturalist. 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 different from each other. Still more striking cases
could be given with respect to the Echinodermata. With the
Meduse or jelly-fishes Professor Allman observes, “the classi-
“ fication of the Hydroida would be a comparatively simple
“task if, as has been erroneously asserted, generically-identical
“ medusoids always arose from generically-identical polypoids ;
“and on the other hand, that generically-identical polypoids
“always gave origin to generically-identical medusoids.” So,
again, Dr. Strethill Wright remarks, “in the life-history of the
“‘ Hydroide any phase, planuloid, polypoid, or medusoid, may
“ be absent.” "”

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 descended from a
common progenitor. During their descent they have diverged
much in structure, but have retained 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 inde-
pendent 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 ereat extent,

independent of each other. Hach organ, says Claude Bernard,’

16 Fritz Miiller’s ‘ Fiir Darwin,’ 1864, ° ™ Prof. Allman, in * Annals and Mag.
s. 65,71. The highest authority on crus- of Nat. Hist.,’ 8rd series, vol. xiii., 1864
taceans, Prof. Milne Edwards, insists p. 348; Dr. 8. Wright, idem, vol. wali
(‘Annal. des Sci. Nat.,’ 2nd series, 1861, p. 127. See also p. 358 for
Zoolog., tom. iii. p. 322) on their meta- analogous statements by Sars.

morphoses differing even in closely 18 ¢ Tissus Vivants,’ 1866, p. 22.
allied genera.

Cuap, XXVII. OF PANGENESIS., 369

has its proper life, its autonomy; it can develop and reproduce
itself independently of the adjoining tissues. The great German
authority, Virchow,” 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 peculiar to
“itself.” Hach element, as Mr. Paget remarks, lives its ap-
pointed time, and then dies, and, after being cast off or absorbed,
is replaced.” I presume that no physiologist doubts that, for
instance, each bone-corpuscle of the finger differs from the
corresponding corpuscle in the corresponding joint of the toe;
and there can hardly be a doubt that even those on the corre-
sponding 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”!
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 acquired a weight of 306 grammes, or
nearly fourteen ounces” The tail of a pig has been grafted
into the middle of its back, and reacquired sensibility. Dr.
Ollier® inserted a piece of periosteum from the bone of a
young dog under the skin of a rabbit, and true bone was
developed. A multitude of similar facts could be given. ‘The

“Cellular Pathology,’ translat, by 22 Mantegazza, quoted in ‘ Popular
Dr. Chance, 1860, pp. 14, 18, 83, 460. Science Review,’ July 1865, p. 522.

*0 Paget, ‘ Surgical Pathology,’ vol. i, 23 ‘De la Production Artificielle des
1853, pp. 12-14. Os, p. 8.
21 Idem, p. 19, ;

370 PROVISIONAL HYPOTHESIS CHAP, XXVIL,

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.” Professor Lionel Beale uses the term “germinal
“matter” for the contents of cells, taken in this wide accepta-
tion, and he draws a broad distinction between germinal matter
and “ formed material” or the various products of cells.% But
the doctrine of omnis cellula e cellulé is admitted for plants, and
is a widely prevalent belief with respect to animals.” 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 retaining the same nature, increase by
self-division or proliferation, 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, must likewise
be greatly changed in nature; this change is apparently attri-
buted 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 opi-
nion on the two opposed doctrines. But every one appears to
admit that the body consists of a multitude of « organic units,”

4 Tsidore Geoffroy St. Hilaire, * Hist, Aspect of Cellular Pathology,’ ‘ Edin-
des Anomalies, tom. ii. pp. 549, 560, burgh Medical Journal,’ April, 1863.
062; Virchow, idem, p. 484. *8 This term is used by Dr, E. Mont-

*5 For the most recent classification gomery (‘ On the Formation of so-called
of cells, see Ernst Hickel’s ‘Generelle Cells in Animal Bodies” 1867, p. 42),

Morpholog.,’ Band ii., 1866, s. 275. who denies that cells are derived from
*° «The Structure and Growth of other cells by a process of growth, but

Tissues, 1865, p. 21, &c. believes that they originate through
7 Dr. W. Turner, ‘The present —_ certain chemical changes.

Cuap, XXVII. OF PANGENESIS. 371

each of which possesses its own proper attributes, and is to a
certain extent independent of all others. Hence it will be con-
venient 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 deviations of structure which
appear in sexual offspring result from changed conditions acting
directly on the organisation, independently of the reproductive
organs. In some 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 countries 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 intemperance; and in many other such cases. Now, as
such changed conditions do not especially affect the reproductive
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 corresponding manner diminished
and increased in comparison with those of the wild duck. A
horse is trained to certain paces, and the colt inherits similar
consensual movements. 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

2B2

372 PROVISIONAL HYPOTHESIS CHAP, XXVII..

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 particular limb or of the brain affect
a small aggregate of reproductive 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 processes graduate
through the repair of injuries into ordinary development and
growth; it might therefore be expected that every character
would be as regularly transmitted by all the methods of re-
production as by continued growth. In the chapters devoted
to inheritance it was shown that a multitude of newly-acquired
characters, 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 ap-
pearing 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 instances, from
the conditions incessantly inducing fresh variability, as with
grafted fruit-trees and highly cultivated flowers. In the re-
maining cases the failure may be attributed to reversion, by
which the child resembles its grandparents or more remote pro-
genitors, 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 discrimination, are distinct powers; and these
powers in some cases are even antagonistic, for each acts alter- |
nately in successive generations. Reversion is not a rare event,
depending on some unusual or favourable combination of circum-
stances, but occurs so regularly with crossed animals and plants, |
and so frequently with uncrossed breeds, that it is evidently an |
essential part of the principle of inheritance. We know that: |

Cuap, XXVIL. OF PANGENESIS. | 373

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 disappeared
during scores, or hundreds, or even thousands of generations,
should suddenly reappear perfectly developed, as in the case
of pigeons and fowls when purely bred, and especially when
crossed ; or as with the zebrine stripes or 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 progenitor, but of which not even a rudiment is left,
suddenly reappears, as with the fifth stamen in some Scro-
phulariaceee. We have already seen that reversion acts in bud-
reproduction ; and we know that it occasionally acts during the
growth of the same individual animal, especially, but not exclu-
sively, 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 reproductive organs are
injured. This comparison of the secondary sexual characters
which are latent in both sexes, with other latent characters,
is the more appropriate 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 in-
telligible, and connect with other facts, this wonderful and

common capacity of reversion,—this power of calling back to
dife long-lost characters ?

| ae

874 PROVISIONAL HYPOTHESIS Cuap, XVII.

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
proliferation, retaining the same nature, and ultimately becomin g
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 “formed 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, simply gem-
mules. 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 transmitted
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 develop-
ment. 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 elements. Hence»
speaking strictly, it is not the reproductive elements, nor the |
buds, which generate new organisms, but the cells themselves
throughout the body. These assumptions constitute the pro- |

AVY

CHAP, XAVII.

OF PANGENESIS. 375

visional hypothesis which I have called Pangenesis. Views in
some respects similar have been propounded, as I find, by other

authors.”

9 Prof. Huxley has called my atten-
tion to the views of Buffon and Bonnet.
The former (‘ Hist. Nat. Gén.,’ edit. of
1749, tom, ii. pp. 54, 62, 329, 333, 420,
425) supposes that organic molecules
exist in the food consumed by every
living creature; and that these mole-
cules are analogous in nature with the
various organs by which they are ab-
sorbed. When the organs thus become
fully developed, 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
throughout the body, his view and
mine would have been closely similar.

Bonnet (‘ Giuvres d'Hist. Nat.,’ tom.
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 emboitement implies that perfect
germs are included within germs in
endless succession, pre-formed and ready
for all sueceeding generations. Accord-
ing to my view, the germs or gemmuleg
of each separate part were not originally
pre-formed, but are continually pro-
duced at all ages during each generation,
with some banded down from preceding
generations.

Prof. Owen remarks (‘Partheno-
genesis,’ 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 derivative germ-cells may remain
“unchanged and become included in
“that body which has been composed
“‘ of their metamorphosed and diversely
“combined or confluent brethren: so
“included, 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 funda-
mentally from mine in the belief that
the primary germ-cell was formed within
the ovarium of the female and was fer-
tilised by the male. My gemmules are
supposed to be formed, quite indepen-
dently of sexual concourse, by each
separate cell or unit throughout the
body, and to be merely aggregated
within the reproductive organs.

Lastly, Mr. Herbert Spencer ( Prin-
ciples of Biology,’ vol. i., 1863-4, chaps.
iv. and viii.) has discussed at consider-
able length what he designates as phy-
siological units. These agree with my
gemmules in being supposed to multiply
and to be transmitted from parent to
child; the sexual elements are sup-
posed to serve merely as their vehicles;
they are the efficient agents in all the
forms of reproduction and in the repairs
of injuries; they account for inherit-
ance, but they are not brought to
bear on reversion or atavism, and this
is unintelligible to me; they are sup-
posed to possess polarity, or, as I call
it, affinity; and apparently they are be-
lieved to be derived from each separate
part of the whole body. But gemmules
differ from Mr. Spencer’s physiological
units, inasmuch as a certain number,
or mass of them, are, as we shall see,
requisite for the development of each
cell or part. Nevertheless I should have
concluded that Mr, Spencer’s views were
fundamentally the same with mine,
had it not been for several passages
which, as far as I understand them,
indicate something quite different. I
will quote some of these passages from
pp. 254-256. “In the fertilised germ

376 PROVISIONAL HYPOTHESIS Cuap, XXVIIi.
Before proceeding to show, firstly, how far these assump-
tions 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 favourable 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
agoregated 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 uninjured cells or units of bone, muscle, nerves, &., are
supposed 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.” Thus, that portion of the lee which had

‘‘we have two groups of physiological
‘‘ units, slightly different in their struc-
“tures.” ... ‘It is not obvious that
‘‘ change in the form of the part, caused
‘* by changed action,involves such change
‘in the physiological units throughout
‘the organism, that these, when groups
‘of them are thrown off in the shape of
“reproductive centres, will unfold into
“‘ organisms that have this part similarly
‘* changed in form. Indeed, when treat-
‘ing of Adaptation, we saw that an
‘* organ modified by increase or decrease
‘* of function can but slowly so react on
‘‘ the system at large as to bring about
‘those correlative changes required to
‘“‘ produce a new equilibrium; and yet
‘only when such new equilibrium has
‘* been established, can we expect it to be
** fully expressed in the modified physio-
‘logical units of which the organism is

‘*’built—only then can we count on a
‘‘complete transfer of the modification
‘“‘to descendants.” .... “That the
“change in the offspring must, other
‘‘ things equal, be in the same direction
‘‘as the change in the parent, we may
‘* dimly see is implied by the fact, that
“ the change propagated throughout the
“parental system is a change towards
‘a new state of equilibrium—a change
‘“‘tending to bring the actions of all
‘organs, reproductive included, into
‘“‘ harmony with these new actions.”

30 M. Philipeaux (* Comptes Rendus,’
Oct. 1, 1866, p. 576, and June, 1867)
has lately shown that when the entire
fore-limb, including the scapula, is ex-
tirpated, the power of regrowth is lost.
From this he concludes that it is neces-
sary for regrowth that a small portion
of the limb should be left. But as in

|

Cuap, XXVIII. OF PANGENESIS. BY As
been cut off, neither more nor less, would 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
amputated 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 development with which to
unite. If from changed conditions or any other cause any part
of the body should become permanently modified, the gem-
mules, 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 diffused
throughout the organisation, and would be transmitted from
generation to generation, so that under favourable 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, apparently in small quantity, together probably with
the presence of gemmules of certain primordial cells, would
constitute the sexual elements. By means of these illustrations
the hypothesis of pangenesis has, I hope, been rendered in-
telligible.

Physiologists maintain, as we have seen, that each cell,
though to a large extent dependent on others, is likewise, to a
certain extent, independent or autonomous. I go one small step
further, and assume that each cell casts off a free gemiule,
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 flower-buds on the same tree; for these are
distinct individuals capable of true or seminal reproduction, yet
have parts in common and are dependent on each other; thus

the lower animals the whole body may deep wound, as in the case of the extir-
be bisected and both halves be repro- pation of the scapula, prevent the for-
duced, this belief does not seem pro- mation or protrusion of the nascent
bable. May not the early closing of a limb?

378 PROVISIONAL HYPOTHESIS Cuap, XXVII,

the tree has its bark and trunk, and certain corals, as the
Virgularia, have not only parts, but movements in common,

The existence of free gemmules is a gratuitous assumption,
yet can hardly be considered as very improbable, 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 undeveloped state. No one probably will object to
this capacity as improbable. The blastema within the ege has
been known to divide and give birth to two embryos; and
Thuret*' has seen the zoospore of an alga divide itself, and both
halves germinate. An atom of small-pox matter, so minute as
to be borne by the wind, must multiply itself many thousand-
fold in a person thus inoculated.” It has recently been ascer-
tained® that a minute portion of the mucous discharge from an
animal affected with rinderpest, if placed in the blood of a
healthy ox, increases so fast that in a short space of time “the
“whole mass of blood, weighing many pounds, is infected, and
“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 genera-
tion 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 undeveloped 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 ege or seed, and within each spermatozoon or pollen-
grain, their number and minuteness must be something incon-

®t “Annal, des Sc. Nat.,’ 3rd series, 9th, 1865, pp. 273, 330.
Bot. tom. 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,’ 1866, p. 446.
in ‘ Medical Times and Gazette,’ Sept.

ap cece

Cuap. XVII. OF PANGENESIS. 379

ceivable. I shall hereafter recur to this objection, which at
first appears so formidable; but it may here be remarked that
a cod-fish has been found to produce 6,867,840 egos, a single
Ascaris about 64,000,000 eggs, and a single Orchidaceous plant
probably as many million seeds.“ In these several cases, the

_ spermatozoa and pollen-grains must exist in considerably larger

numbers. Now, when we have to deal with numbers such ag
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 must 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 fragment of a leaf will reproduce the whole.
But a difficulty here occurs; it would appear that with plants,
and probably 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, Bridgman® has proved that, when spores (which it
should be remembered are of the nature of buds) are taken from
® monstrous part of a frond, and others from an ordinary part,

** Mr. F. Buckland carefully calcu-
lated, by weighing, the above number of
eggs in a cod-fish ; see ‘ Land and Water,’
1868, p. 62. In a previous instance
he found the number to be 4,872,000.
Harmer (‘ Phil. Transact.,’ 1767, p. 280)
found only 3,681,760 eggs. For the
Ascaris, see Carpenter’s ‘Comp. Phys.,’
1854, p. 590. Mr. J. Scott, of the
Royal Botanic Garden of Edinburgh,
calculated, in the same manner as
I have done for some British orchids
(‘Fertilisation of Orchids,’ p. 344),
the number of seeds in a capsule of
an Acropera, and found the number
to be 371,250. Now this plant produces
several flowers on a raceme and many
racemes during a season. In an allied

genus, Gongora, Mr. Scott has seen
twenty capsules produced on a single
raceme: ten such racemes on the
Acropera would yield above seventy-
four millions of seed. I may add that
Fritz Miiller informs me that he found
in a capsule of a Maxillaria, in South
Brazil, that the seed weighed 423
grains: he then arranged half a grain
of seed in a narrow line, and by count-
ing a measured length found the number
in the half-grain to be 20,667, so that
in the capsule there must have been
1,756,440 seeds! The same plant some-
times produces half-a-dozen capsules,

* ‘Annals and Mag. of Nat. Hist.,’
3rd series, vol. viii,, 1861, p. 490.

9 A at ATE Wee ge ig

380 ; PROVISIONAL HYPOTHESIS Cap, XXVII.

each reproduces the form of the part whence derived. But
this non-diffusion of the gemmules from bud to bud may be

only apparent, depending, as we shall hereafter see, on the
nature of the first-formed cells in the buds.

The assumed elective affinity of each.gemmule for that par-

ticular cell which precedes it in the order of development. 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 that about ten
thousand species of Composite exist, and there can be no doubt
that if the pollen of all these species 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 ac-
quired 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 contained 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 subse-
quently to impregnation, so that corresponding parts alone

affect each other; thus, a calf produced from a short-horned ©

cow by a long-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 phy-
siologists have insisted, an affinity for special organic sub-
stances, 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 vesicatoria the kidneys ; and in the poisonous
matter of many diseases, as small-pox, scarlet-fever, hooping-
cough, glanders, 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

3° Paget, ‘Lectures on Pathology,’ 294; Claude Bernard, ‘Des Tissus
p. 27; Virchow, ‘Cellular Pathology,’ Vivants,’ pp. 177, 210, 337; Miller's
translat. by Dr. Chance, pp. 123, 126, ‘ Physiology,’ Eng. translat., p. 290.

a

Cuap, XXVILL OF PANGENESIS. 381

their early development was shown in the last chapter,
when discussing the tendency to fusion in homologous parts.
This affinity displays itself in the normal fusion of organs

‘which. are separate at an early embryonic 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 organs 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 gem-
mule 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 develop-
ment 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 developed into different struc-
tures, from absorbing peculiar kinds of nutri ment, 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 cells which
have become abnormal. In the regular growth and repair of
bones, the tissues undergo, as Virchow remarks, a whole series.
of permutations and substitutions, «'The cartilage cells may be

37 Virchow, ‘ Cellular Pathology,’ trans, by Dr. Chance, 1860, pp. 60, 162, 245,
441, 454, 88 Idem, pp. 412-426.

382 PROVISIONAL HYPOTHESIS CHAP, XXVII.

“converted by a direct transformation 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 completely
“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 hypothesis that gemmules
derived from one kind of tissue combine with the cells of another
kind, and cause the successive modifications.

It is useless to speculate at what period of development each
organic unit casts off its gemmules; for the whole subject of the
development of the various elemental 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 pro-
bable that all external agencies, such as changed nutrition,
increased use or disuse, &¢., which induced any permanent modi-
fication 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 atoms.

There is another point on which it is useless to speculate,
namely, whether all gemmules are free and separate, or whether
some are from the first united into small aggregates. A feather,
for instance, is a complex structure, and, as each separate part
is liable to inherited variations, I conclude that each feather
certainly generates a large number of gemmules; but it is
possible that these may be aggregated into a compound gem-
mule, 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 modifications transmitted;
consequently, separate gemmules, according to our hypothesis,

nvolval
un that
ch ar
rption:
| Beale
by the
nuclei}
1S plo
ition,

modi

Cuap, XXVII, OF PANGENESIS. 383

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 petaliform, or parts or mere stripes of the calyx
assuming the colour and texture of the corolla, it is probable
that with 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 several foregoing
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 ennumerated in the First Part,
All the forms of reproduction 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 aggregation
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 pro-
cesses the same living creature igs habitually produced, are
fundamentally the same. Parthenogenesis is no longer won-
derful; in fact, the wonder is that it should not oftener occur.
We see that the reproductive organs do not actually create
the sexual elements ; they merely determine or permit the
aggregation of the gemmules in a special manner. These
organs, together with their accessory parts, have, however,
high functions to perform ; they give to both elements a special
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 contrivances for these purposes are
sometimes wonderfully complex, as with the spermatophores of
the Cephalopoda. The male elephant sometimes possesses attri-
butes which, if observed in an independent animal, would be put
down to instinct guided by sense-organs, as when the spermato-

|

384 PROVISIONAL HYPOTHESIS. CHAP, XXVII.

zoon of an insect finds its way into the minute micropyle of the
ego, or as when the antherozoids of certain alge swim by
the aid of their cilia to the female plant, and force themselves
into a minute orifice. In these latter cases, however, we must
believe that the male element has acquired its powers, on the
same principle with the larvee 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 premature larva, which unites, or, like one of the
lower alge, conjugates, with the female element. What deter-
mines 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 symmetrical
erowth of trees and corals, nor why adventitious buds may be
formed almost anywhere, even on a petal, and frequently upon
healed wounds.” As soon as the gemmules have aggregated
themselves, development apparently commences, but in the case
of buds is often afterwards suspended, and in the case of the
sexual elements 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,” though ex-
ceptions occur,"! 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,
&e., and the production of seed, is partly explained by the
gvemmules not existing in sufficient numbers for both processes.

39 See Rev. J. M. Berkeley, in ‘ Gard.
Chron.,’ April 28th, 1866, on a bud
developed on the petal of the Clarkia.
See also H. Schacht, ‘ Lehrbuch der
Anat.,’ &c., 1859, Theile ii, s, 12, on
adventitious buds.

40 Mr. Herbert Spencer (‘ Principles
of Biology,’ vol. ii p. 430) has fully
discussed the antagonism between
growth and reproduction.

41 The male salmon is known to breed
at a very early age. The Triton and
Siredon, whilst retaining their larval
branchie, according to Filippi and
Duméril (‘Annals and Mag. of Nat.

Hist.,’ 3rd series, 1866, p. 157), are
capable of reproduction. Ernst Hackel
has recently (‘Monatsbericht Akad.
Wiss. Berlin,’ Feb. 2nd, 1865) ob-
served the surprising case of a medusa,
with its reproductive organs active,
which produces by budding a widely
different form of medusa; and_ this
latter also has the power of sexual re-
production. Krohn has shown (‘ Annals,
and Mag. of Nat. Hist.,’ 3rd series, vol.
xix. 1862, p. 6) that certain other
medusee, whilst sexually mature, pro-
pagate by gemma.

atly ty

Porecatel .

D the cag
se of the

2 opposite”

sed germ,

4

during 3

ough &

of sextil
matio-
rhizomes

| by the ;

races o

157), &
ast pk
oht Abt
ra ped

ns acl

“doit

Cuap, XXVIL. OF PANGENESIS, 385

But this explanation hardly applies to those plants which
naturally produce a multitude of seeds, but which, through a
comparatively small increase in the number of the buds on
their rhizomes or offsets, yield few or no seed. As, however,
we shall presently see that buds probably include tissue which
has already been to a certain extent developed or differentiated,
some additional organised matter will thus have been expended.

From one of the forms of Reproduction, namely, spontaneous
self-division, we are led by insensible steps to the repair of the
slightest injury ; and the existence of gemmules, derived from
every cell or unit throughout the body and everywhere diffused,
explains all such cases,—even the wonderful fact that, when the
limbs of the salamander were cut off many times successively
by Spallanzani and Bonnet, they were exactly and completely
reproduced. I have heard this process compared with the re-
crystallisation which occurs when the angles of a broken crystal
are repaired; and the two processes have this much in common,
that in the one case the polarity of the molecules is the efficient
cause, and in the other the affinity of the gemmules for par-
ticular nascent cells,

Pangenesis does not throw much light on Hybridism, but
agrees well with most of the ascertained facts. We may con-
clude from the fact of a single spermatozoon or pollen-grain
being insufficient for impregnation, that a certain number of
gemmules derived from each cell or unit are required for the
development of each part. From the occurrence of parthe-
nogenesis, 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 includes nearly sufficient gemmules
of all kinds for independent development, so that when
united with the male element the gemmules must be super-
abundant. Now, as a general rule, when two species or races
are crossed reciprocally, 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 between
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
VOL. IL a4

386 PROVISIONAL HYPOTHESIS Cuap. XXVII.

the admission that the gemmules in the fertilised germ are
superabundant in number, and that those derived from one
parent have some advantage 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 generations,
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 themselves into distinct stripes or
blotches; and reasons were given, when discussing in the fif-
teenth chapter the incompatibility 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 transmis-
sion of character over the other; and this we can 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 pre-
potent. When we consider latent 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 offspring; 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 developing cells or units, we need not
feel at all surprised that the commixture of gemmules derived
from two distinct 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 exclusively on the
reproductive organs being specially affected; but why these
organs should be thus affected we do not know, any more than

42 See his excellent discussion on this subject in ‘Nouvelles Archives du
Muséum,’ tom. i. p. 151.

Cuap, XXVII. OF PANGENESIS. 387

why unnatural conditions of life, 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 per-
fectly 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 off
hybridised cell-gemmules, which become ageregated 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 unnatural conditions, fail to produce
seed, but can readily be propagated by buds. We shall
presently see that pangenesis agrees well with the strong ten-
dency to reversion exhibited by all crossed animals and plants.

As by our hypothesis budding or fission differs from geminal
generation only in the manner in which the gemmules are first
aggregated, we can understand the possibility of the formation of
graft-hybrids; and these grait-hybrids, which combine the
characters of the two forms of which the tissues have become
united, connect in the closest and most interesting manner gem-
mation and sexual reproduction.

Abundant evidence has been advanced proving that pollen
taken from one species or variety and applied to the stigma of
another sometimes directly affects the tissues 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 ordinary theory of reproduction this is a most
anomalous circumstance, 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 gemmules, derived from
every part of the organisation, which diffuse themselves and

multiply by self-division: hence it is not surprising that gem-

mules 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.
202

388 PROVISIONAL HYPOTHESIS Cuar. XXVIL.

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 con-
clude that the gemmules derived from the foreign pollen do not
become developed merely in contact with pre-existing cells, but
actually penetrate 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 de-
velopment 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 organ-
isms, as we shall presently see, the cells or organic units of
the embryo during the successive stages of 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 element
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 impregnation, 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 gemmules included within the spermatozoa of the pre-
vious male.

Hach organism reaches maturity through a longer or shorter
course of development. The changes may be small and insen-
sibly slow, as when a child grows into a man, or many, abrupt,
and slight, as in the metamorphoses 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
corresponding part, and in this case it will appear, falsely as I
believe, to be formed from tbe old part; or it may be developed
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 where no eye previously existed. We have also seen
that allied organic beings in the course of their metamorphoses
sometimes attain nearly the same structure after passing

Cuap, XXVII. OF PANGENESIS. 889

through widely different forms; or conversely, after passing
through nearly the same early forms, arrive at a widely
different termination. 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 structures
wholly different in form, position, and function. But these cases
become plain on the hypothesis of pangenesis. The organic
units, during each stage of development, throw off gemmules,
which, multiplying, are transmitted 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 struc-
ture of the part at this particular stage of development became
greatly changed, but this would not necessarily affect other
parts whether previously or subsequently developed. In this
manner we can understand the remarkable independence of
structure in the successive metamorphoses, and especially in the
successive metageneses of many animals. ,

The term growth ought strictly to be confined to mere
increase of size, and development to change of structure.* Now,
a child is said to grow into a man, and a foal into a horse, but,
as in these cases there is much change of structure, the process
properly belongs to the order of development. We have indirect
evidence of this in many variations and diseases supervening
during so-called growth at a particular period, and being in-
herited at a corresponding 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

43 Various physiologists have insisted instance in microcephalous idiots, in
- on this distinction between growth and which the brain continues to gTow
development. Prof. Marshall (Phil. after having been arrested in its deve-
‘Transact.,’ 1864, p. 544) gives a good lopment.

390 PROVISIONAL HYPOTHESIS Cuap, XXVIL

must suppose that the organs were in fact affected at an earlier
ave and threw off at this period affected gemmules; 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 indi-
viduals are generated asexually during very early or later stages
of development. These individuals may closely resemble the
preceding larval form, but generally are wonderfully dissi-
milar. ‘To understand this process we must suppose that at
a certain stage of development the gemmules are multiplied
at an unusual rate, and become aggregated by mutual affinity
at many centres of attraction, or buds. These buds, 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 numerous these
may be. It was shown in the First Part, at least in regard to

animals, that the new beings which are thus at any period

asexually generated do not retrograde 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 improbable, 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 gem-
mules derived from the earlier-formed cells, but only with those
which came next in the order of development. On the other
hand, we must believe that, in the sexual elements, or probably
in the female alone, gemmules 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

|
|
|

exual
these
rd to

eTI00

Cuap. XXVII. OF PANGENESIS. 391

so far as its development depends on the union of the proper
gemmules with certain nascent cells, together with the super-
abundance 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 are 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 reproduced, and
when the foot of the salamander is divided longitudinally, ad-
ditional digits are occasionally formed. When frogs, toads, &c.,
are born with their limbs doubled, as sometimes occurs, the
doubling, as Gervais remarks,“ cannot be due to the com-
plete fusion of two embryos, with the exception of the limbs,
for the larvee are limbless. ‘The same argument is applicable”
to certain insects produced with multiple legs or antenna, for
these are metamorphosed from apodal or antenneless larvae.
Alphonse Milne-Edwards* has described the curious cage of
a crustacean in which one eye-peduncle supported, instead of a
complete eye, only an imperfect cornea, out of the centre of
which a portion of an antenna was developed. A case has been
recorded“ 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 known® of additional teeth having been developed in
the palate, more especially with horses, and in the orbit of the
eye. Certain breeds of sheep bear a whole crowd of horns
on their foreheads. Hairs occasionally appear in strange
situations, as within the ears of the Siamese hairy family ;
and hairs “quite natural in structure” have been observed
‘within the substance of the brain.” 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 topknot of hackles

44 “ Compte Rendu, Noy. 14, 1864, p. 47 Sedgwick, in ‘ Medico-Chirurg,
800. Review,’ April 1863, p. 454.

4 As previously remarked by 48 Tsid. Geoffroy St. Hilaire, ‘ Hist.
Quatrefages, in his ‘ Metamorphoses deg Anomalies,’ tom. i., 1832, pp. 435,
de ’Homme,’ &c., 1862, p. 129, 657; and tom. ii. p. 560.

46 Ginther’s ‘ Zoological Record,’ 49 Virchow, ‘Cellular Pathology,’
1864, p. 279. 1860, p. 66.

392 PROVISIONAL HYPOTHESIS Cuap. XXVII,

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. ven the elemental parts of the same feather may be
transposed ; for in the Sebastopol goose, barbules are developed
on the divided filaments of the shaft.

Analogous cases are of such frequent occurrence with plants
that they do not strike us with sufficient surprise. Super-
numerary petals, stamens, and pistils, are often produced. I
have seen a leaflet low down in the compound leaf of Vicia
sativa converted into a tendril, and a tendril possesses many
peculiar properties, such as spontaneous movement and irrita-
bility. The calyx sometimes assumes, either wholly or by
stripes, the colour and texture of the corolla. Stamens are so fre-
quently 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 included
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 including one of the highest products of
the plant, namely the pollen; for instance, I have seen in an
Ophrys a pollen-mass with its curious structure of little packets,
united together and to the caudicle by elastic threads, formed
between the edges of an upper petal. The segments of the
calyx of the common pea have been observed partially converted
into carpels, including ovules, and with their tips converted into
stigmas. Numerous analogous facts could be given.”

I do not know how physiologists look at such facts as the
foregoing. According to the doctrine of pangenesis, 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 nascent state ; and this would
follow from a slight modification 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

°° Moquin-Tandon, ‘ Tératologie Vég.,’ 1841, pp. 218, 220, 353. For the case
of the pea, see ‘Gardener's Chron.,’ 1866, p. 897.

at such

ls have
cluded
e their
ccount
atural
il may
ucts of
) 1 al
ackets,

orl ed]

Cuap, XXVIL. ‘OF PANGENESIS. 393

under domestication, when we remember the many curious
cases given, in the seventeenth chapter, of cultivated plants
which absolutely refuse to be fertilised by their own pollen
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 membrane
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 position, 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. When parts which are homologous 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 gemmules must be extremely
numerous, as well as the points to which they ought to become
united; and, in accordance 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 homo-
logous parts; and with respect to mere cohesion there is pro-
bably always some degree of fusion, at least near the surface.
When two embryos during their early development come into
close contact, as both include 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
ageregate of cells, and thus give rise to a single part or organ.

|
|
|

394 PROVISIONAL HYPOTHESIS Cuap, XXVII.

For instance, two embryos might thus come to have on their
adjoining sides a single symmetrical arm, which in one senso
will have been formed by the fusion of the bones, muscles, &e.,
belonging to the arms of both embryos. In the case of the fish
described by Lereboullet, in which a double head was geen
gradually to fuse into a single one, the same process must haya
taken place, together with the absorption of all the parts which
had been already formed. These cases are exactly the reverse
of those in which a part is doubled either spontaneously or after
an injury; for in the case of doubling, the superabundant gem-
mules of the same part are separately 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 derived
from the various parts of the body are probably aggregated in
an irregular manner, some superfluous and others deficient.
Whether a superabundance of gemmules, 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 necessarily 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 hybridised, so,
in the case of a cell, if the properly succeeding gemmules were
absent, it would probably combine easily with other and allied
gemmules. We see this in the case of imperfect nails growing
on the stumps of amputated fingers, for the gemmules of the
nails have manifestly 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 tissués of the body, according to the
doctrine of pangenesis, are directly affected by the new con-
ditions, and consequently throw off modified gemmules, which

5! Miller's ‘ Physiology,’ Eng. translat., vol, i. p. 407.

im.
l lorm a

e Ol two

show,
ted by
{ leri ved
ated in
ficient,

fusion

Ol aly

( wig

of the

Cuap, XXVIL. OF PANGENESIS. 395

are transmitted with their newly acquired peculiarities to the
offspring. 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 sup-
pose that certain cells become at last not only functionally but
structurally modified ; and that these throw off similarly 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 profoundly igno-
rant 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 modification is transmitted ;” and this implies, ac-
cording to our hypothesis, that gemmules derived from modified
nerve-cells are transmitted to the offspring.

It is generally, perhaps always, necessary that an organism
should be exposed during several generations to changed con-
ditions or habits, in order that any modification in the struc-
ture 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 explanation 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 eenera-
tions, but that the gemmules derived from the same cells after
modification, naturally go on increasing under the same favour-
ing conditions, until at last they become sufficiently numerous
to overpower and supplant the old gemmules.

°2 See some remarks to this effect by Sir H. Holland in his ‘Medical Notes,’
1839, p. 32.

596 PROVISIONAL HYPOTHESIS Crap, XXVII,

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 propagated by sexual
and asexual generation. As far as variability depends on the
imperfect action of the reproductive organs under changed con-
ditions, 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
within 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 alter-
nate 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
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 propagated 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 trans-
position of gemmules, and on the redevelopment 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

ne Ww
thet

| Lag bee,
the Seq
' Metime
ised from
Ing alter
Yelena

4 already
S lormel
lent, and
SI ructure
Inducing

sufficient

a similar
nd seed,
or buds,
var! ably
‘iplied t
TS10D by
ate chi
t. Hare
= egated
ess fit
but the
variall}
.siS thal

* agus”

Cuap, XXVII, OF PANGENESIS. See

variability. Secondly, in the cases in which the organisation
has been modified by changed conditions, the increased use or
disuse 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 developed into new and
changed structures.

Turning now to Inheritance; if we suppose a homogeneous
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 have the simplest form
of inheritance.* Precisely the same view may be 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 suffi-
ciently discussed the inheritance of the direct effects of changed
conditions, and of increased use or disuse of parts, and, by im-
plication, the important principle of inheritance at corresponding
ages. These groups of facts are 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 sup-
pression of organs. When a part becomes diminished by
disuse prolonged during many generations, the principle of
economy of growth, as previously explained, will tend to reduce
it still further; but this will not account for the complete or

almost complete obliteration of, for instance, a minute papilla

of cellular tissue representing a pistil, or of a microscopically
minute nodule of bone representing a tooth. In certain cases
of suppression 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 gemmules themselves no doubt have perished ; nor is this

°3 This is the view taken by Prof.
Hackel, in his ‘Generelle Morphologie’
(B. ii. s. 171), who says: “ Lediglich
die partielle Identitat der specifisch-

constituirten Materie im elterlichen und
im kindlichen Organismus, die Thei-
lung dieser Materie bei der Fortpflan-
zung, ist die Ursache der Erblichkeit.”

398 PROVISIONAL HYPOTHESIS Cnar. XxVit

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 derived from an enfeebled and use-
less rudiment would be 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 in-
herited result follow ; and this is an apparent objection 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 ego; and such
mutilations, when naturally caused, would appear like con-
genital deficiencies, which are occasionally inherited. In the
second place, according to our hypothesis, gemmules multiply
by self-division and are transmitted from generation to gene-
ration; so that during a long period they would be present and
ready to reproduce a part which was repeatedly amputated.
Nevertheless it appears, from the facts given in the twelfth
chapter, that in some rare cases mutilations have been inhe-
rited, but in most of these the mutilated surface became diseased.
In this case it may be conjectured 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
individual 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 periect
animal of the opposite sex, often transmits its deficiency.

The last subject that need here be discussed, namely Rever-
sion, 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 18
possible. We plainly see this distinction in the many cases in
which a grandfather transmits to his grandson, through his
daughter, characters which she does not, or cannot, possess
Why the development of certain characters, not necessarily 12
any way connected with the reproductive organs, should be co-
fined to one sex alone—that is, why certain cells in one sex

multiply
to rene
sent and
hputated
> twelfth
en inhe.

diseased,
f the lost
1 surface,
3 injure!
his might
I rinciple

a periet
a pe

ry Reve

Jopmet!

Cuar, XXVIL. OF PANGENESIS. 399

should unite with and cause the development of certain gem-
mules—we do not in the least know; but it is the coinmon
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 latent, 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 cha-
racters in the male. Why in the female, when her ovaria
become diseased or fail to act, certain masculine gemmules
become 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 pro-
genitors quite fail to be developed. 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 appear that a slight change in the
constitution of an animal, in connection with the state of
the reproductive 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 recur-
rent season, certain cells or parts acquire an affinity for cer-
tain gemmules, which become developed into the secondary
masculine characters; but if the reproductive organs be de-
stroyed, or even temporarily disturbed by changed conditions,
these affinities are not excited. Nevertheless, the male, before
he arrives at puberty, and during the season when the species
does not breed, must include the proper gemmules in a latent
state. The curious cage formerly given of a Hen which assumed
the masculine characters, not of her own breed but of a remote
progenitor, illustrates the connection between latent sexual cha-
racters and ordinary reversion. With those animals and plants
which habitually produce several forms, as with certain butter-

flies described by Mr. Wallace, in which three female forms and

400 PROVISIONAL HYPOTHESIS Cap, XXVII,

the male exist, or as with the trimorphic species of Lythrum
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, com-
bined with the transposition of organs, may be applied to those
singular cases of butterflies and other insects, 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
distinct line, sometimes differ in the most conspicuous manner.
Again, these same principles apply to the cases given in the thir-
teenth chapter, in which the right and left sides of the bod y 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 essential part of the
general law of inheritance. It occurs with beings, however
propagated, whether by buds or seminal generation, and some-
times may even be observed in the same individual as it advances
in age. The tendency to reversion is often induced by a change
of conditions, and in the plainest manner by the act of crossing.
Crossed forms are generally at first nearly intermediate in cha-
racter between their two parents; but in the next generation
the offspring generally revert to one or both of their grand-
parents, and occasionally to more remote ancestors. How can
we account for these facts? Hach 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 con-
dition, they would, it is probable, be enabled to multiply largely
during the lifetime of each hybrid. Consequently the sexual
elements of a hybrid will include both pure and hybridised
gemmules; and when two hybrids pair, the combination of pure
gemmules derived from the one hybrid with the pure gem-
mules of the same parts derived from the other would neces-

Hap Uy,

Lyi Crap, XXVIL OF PANGENESIS. 401
al Wide, | sarily lead to complete reversion of character ; and it is, perhaps,
a not too bold a supposition that unmodified and undeteriorated
Leng, Cn, gemmules of the same nature would be especially apt to com-
1 to thos. bine. Pure gemmules in combination with hybridised gemmules
‘h eae : would lead to partial reversion. And lastly, hybridised gem-
®, and ih, mules derived from both parent-hybrids would simply reproduce
his Coton the original hybrid form.*4 All these cases and degrees of

ther ¥ reversion incessantly occur.
Mai It was shown m the fifteenth chapter that certain characters
0 the tn. are antagonistic to each other or do not teadily blend together ;
ody dit hence, when two animals with antagonistic characters are crossed,
a onl it might well happen that a sufficiency of gemmules in the male

alone for the reproduction of his peculiar characters, and in the
female alone for the reproduction of her peculiar characters,
would not be present ; and in this case dormant gemmules derived
from some remote progenitor might easily gain the ascendency,
and cause the reappearance of long-lost characters. For instan ce,

‘Ss for m
¥ under)

nto action

rt of the when black and white pigeons, or black and white fowls, are
- howere crossed,—colours which do not readily blend,—blue plumage in
ind some. the one case, evidently derived from the rock-pigeon, and red
advances plumage in the other case, derived from the wild jungle-cock,
a change occasionally reappear. With uncrossed breeds the same result
ated would follow, under conditions which favoured the multiplica-
be sn tion and development of certain dormant gemmules, as when
eneraiia animals become feral and revert to their pristine character. A

certain number of gemmuleg being requisite for the development
of each character, as is known to be the case from several sper-
matozoa or pollen-graing being necessary for fertilisation, and
time favouring their multiplication, wil] together account for the
curious cases, insisted on by Mr. Sedgwick, of certain diseases
regularly appearing in alternate generations. This likewise
holds good, more or legs strictly, with other weakly inherited mo-

iT gral
How cil
prid mus
panda
idily a
sis thet

rom be! difications. Hence, as I have heard it remarked, certain diseases
-mpal _ appear actually to gain strength by the intermission of a genera-
ly Jang tion. The transmission of dormant gemmulegs during many
- ses successive generations ig hardly in itself more improbable, as

ri *4 In these remarks I, in fact, follow crossed. See his excellent memoir in
Dp ol} Naudin, who speaks of the elements or the ‘Nouvelles Archives du Muséum,’
re essences of the two species which are tom. i. p. 151,

ects VOL. II. 2D
d 2

402 PROVISIONAL HYPOTHESIS Cuap. XXVII,

previously remarked, than the retention during many ages of
rudimentary organs, 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, Ex.
cessively 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 improbable 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 parents,
and resemble its grandparents, or ancestors removed by many
generations.

Conclusion.

The hypothesis of Pangenesis, as applied to the several great
classes of facts just discussed, no doubt is extremely complex;
but so assuredly are the facts. The assumptions, 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 off free and minute atoms of their contents, that
is gemmules. 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 successive generations. °

In a highly organised and complex animal, the gemmules
thrown off from each different cell or unit throughout the body
must be inconceivably numerous and minute. Each unit of each
part, as it changes during development, and we ‘know that some
insects undergo at least twenty metamorphoses, must throw off
its gemmules. All organic beings, moreover, include many
dormant gemmules 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-gramn.
Such an admission will be declared impossible; but, as previously

Wonderfy}
Its parents,
by many

veral prea
y compler;
owever, (ll
complex i
its, beside
ing by sel
tents, thi
selves int
depends :
are cape
ations.
cern
tthe In!
it of et”

Cap. XXVII. OF PANGENESIS. 403

remarked, number and size are only relative difficulties, and
the eggs or seeds produced by certain animals or plants are so
numerous that they cannot 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 the olfactory
nerves. An analogy more appropriate is afforded by the con-
tagious 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 powerfully 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 diff-
culty, 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 phy-
siologists to be autonomous, like the buds on a tree, but ina
less degree. I go one step further and assume 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 provisionally accepted, we
must look at all the forms of asexual reproduction, whether oc-
curring at maturity or as in the case of alternate generation
during youth, as fundamentally the same, and dependent on the
mutual ageregation 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 insuf-
ficient number of gemmules being ageregated within the separate
sexual elements, and probably in the presence of certain primor-
dial cells. The development of each being, including all the
2D 2

404 PROVISIONAL HYPOTHESIS OF PANGENESIS. Cuap. XXVII.

forms of metamorphosis and metagenesis, as well as the go-
called growth of the higher animals, in which structure changes
though not in a striking manner, depends on the presence of
gemmules thrown off at each period of life, and on their develop-
ment, at a corresponding period, in union with preceding cells,
Such cells may be said to be fertilised by the gemmules which
come next in the order of development. Thus the ordinary act
of impregnation and the development of each being are closely
analogous processes. 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 fore-
father to his descendants of dormant gemmules, which occa-
sionally become developed 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 in-
herited 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 repro-
duction, the variability, the development and renovation of each
living organism. No other attempt, as far as I am aware, has
been made, imperfect as this confessedly is, to connect under
one point of view these several grand classes of facts. We
cannot fathom the marvellous complexity of an organic being;
but on the hypothesis here advanced this complexity is much
increased. Each living creature must be looked at as a mi-
crocosm—a, little universe, formed of a host of self-propagating
organisms, inconceivably minute and as numerous as the stars ™

heaven.

UCCessiyehy
a8 Well y
r the ext
ely a for
unicelluly
1 the fore
hich ocey.
> unknom
d to a bal
>, some li

we heart

s of al It
expressill
h separilé
the rept
‘on of eatt

Cuap, XXVIII. CONCLUDING REMARKS, 405

CHAPTER XXVIII.

CONCLUDING REMARKS.

DOMESTICATION — NATURE AND CAUSES OF VARIABILITY — SELECTION — DIVER-
GENCE AND DISTINCTNESS OF CHARACTER — EXTINCTION OF RACES — CIRCUM-
STANCES FAVOURABLE TO SELECTION BY MAN — ANTIQUITY OF CERTAIN RACES —
THE QUESTION WHETHER EACH PARTICULAR VARIATION HAS BEEN SPECIALLY PRE-
ORDAINED,

As summaries have been added to nearly all the chapters, and
as, in the chapter on pangenesis, various subjects, 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 general 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 circumstances the
number of domesticated animals has never been large. With
respect to plants, I have shown in the ninth chapter how their
varied uses were probably first discovered, and the early steps in
their cultivation. Man could not have known, when he first
domesticated 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

406 CONCLUDING REMARKS. CHAP. XXVIII,

could man have foreseen whether his animals and plants would
vary in succeeding 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,—under all these circumstances do-
mesticated animals and plants have varied to a much greater
extent than the forms which in a state of nature are ranked as
one species. Why certain animals and plants have varied
more under domestication than others we 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 accumulated; 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 organisation,—is one of the most important facts
which we learn from the numerous 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 pro-
phetic instinct choose those species which would 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

& Varia

OW, any
l othen
judge o
‘ous and
ases this
ariations
ons vil
+ closely
r-endiny
t icity 0
ant facts
e earlie!

ants ca
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~~

Cuap, XXVIU. CONCLUDING REMARKS. 407

rear, for instance, curious breeds of the fowl, pigeon, or canary-
bird.

From several causes it is. difficult to judge of the amount
of modification which our domestic productions have under-
gone. 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 do-
mesticated, 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
exaggerated by some authors. A few individuals of one form
would seldom permanently affect another form existing in much
ereater numbers; for, without careful selection, the stain of the
foreign blood would soon be obliterated, and during early and
barbarous times, when our animals were first domesticated,
such care would seldom have been taken.

There is good reason to believe that several of the breeds of
the dog, ox, pig, and of some other animals, are respectively

descended from distinct wild prototypes; nevertheless the belief

in the multiple origin of our domesticated animals has been
extended by some few naturalists and by many breeders to an
unauthorised extent. Breeders refuse to look at the whole
subject under a single point of view; I have heard one, who
maintained that our fowls were the descendants of at least
halt-a-dozen aboriginal species, protest that he was in no way
concerned 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 improbability 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 assum p-
tion of so much recent 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,

408 CONCLUDING REMARKS. Cuap, XXVIII.

they often ignore the whole subject of geographical distribu-
tion as completely as if its laws were the result of chance,

Although from the reasons just assigned it is often difficult
to judge accurately of the amount of change which our domesti-
cated 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 extent possible in the case of animals descended from
several 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 domesticated animals and
cultivated plants. I have in many instances purposely given
details on new and strange peculiarities which have arisen. No
part of the organisation escapes the tendency to vary. The
variations generally affect parts of small vital or physiological
importance, but so it is with the differences which exist
between closely allied species. In these unimportant cha-
racters 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, &e., of
the hair, feathers, horns, and other dermal appendages.

Tt 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 improved 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 foramen, atlas, and other cervical vertebra,
The whole shape of the brain, together with the skull, has
been modified in Polish fowls; in other breeds of the fowl
the number of the vertebrae and the forms of the cervical
vertebree 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 cesophagus, have all varied. In certain quadru-
peds the length of the intestines has been much increased or

“Ov

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ed from
Is Sivey
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Cuap, XXVUI. CONCLUDING REMARKS. 409

diminished. With plants we see wonderful differences in the
stones of various fruits. In the Cucurbitaces several highly
important characters have varied, such as the sessile position of
the stigmas on the ovarium, the position of the carpels within
the ovarium, and its projection out of the receptacle. But it
would be useless to run through the many facts given in the
earlier chapters.

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 distinct wild types. New mental characters
have certainly often been acquired, and natural ones lost, under
domestication. | .

’ 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 caterpillars 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 embryology. 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 acquirement by animals in a state of nature of
secondary sexual characters,

Tt has sometimes been said that our domestic productions 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 dentition, 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

410 CONCLUDING REMARKS, Cuap, XXVIII

our poultry and pigeons the acquirement of down and of the
first plumage by the young, and of the secondary sexual cha-
racters by the males, differ. The number of moults through
which the larve 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 ten-
dencies 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 through-
out the winter, the proportion and nature of certain chemical
compounds in the tissues or seeds, all vary.

There is, however, one important, constitutional difference
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 dis-
tinct domestic races, with the exception of a very few plants,
when similarly crossed. It certainly appears a remarkable fact
that many closely allied species which in appearance differ ex-
tremely 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 fer-
tile, 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 illegitimate unions and
illegitimate offspring of dimorphic and trimorphic plants. In
the second place, the Pallasian doctrine, that species after having
been lone domesticated lose their natural tendency to sterility
when crossed, 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 un-
reasonable to expect that races formed under domestication

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Cuap, XXVIII. CONCLUDING REMARKS, 411

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 reproduc-
tive 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 incom-
parably longer period of time than have domestic races; and
we positively 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 resemble
species when crossed in transmitting their characters 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 almost, or even quite, as firmly as species.
With both, the conditions leading to variability and the
laws governing 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 clas-
sification is certainly founded, and with species is apparently
founded, on community of descent, together with the amount of
modification which the forms have undergone. The characters
by which domestic varieties differ from each other are more

412 CONCLUDING REMARKS, Cuap, XXVIII.

variable than those distinguishing species, though hardly more
so than with certain protean species; but this greater degree
of variability is not surprising, as varieties have generally been
exposed within recent times to fluctuating conditions of life,
are much more lable to have been crossed, and are still in
many cases undergoing, or have recently undergone, modifica-
tion by man’s methodical or unconscious selection.

Domestic varieties as a general rule certainly differ from each
other in less important parts of their organisation than do
species; and when important differences occur, they are seldom
firmly fixed; but this fact is intelligible if we consider man’s
method of selection. In the living animal or plant he cannot
observe internal modifications 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 liable to numerous
slight variations, and as these would probably be inherited, for
many strange monstrosities are transmitted, man could un-
doubtedly effect a certain amount of change in these organs.
When he has produced any modification in an important part,
it has generally been unintentionally in correlation with some
other conspicuous part, as when he has given ridges and protu-
berances 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 external form of the pouter-
pigeon, he has enormously increased the size of the cesophagus,
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
greatly modified the form of the lower mandible ; and so in many
other cases. Natural species, on the other hand, have been mo-
dified exclusively for their own good, to fit them for infinitely

er Man
cannot
Organs:
ible with
nY slight
Aditional
ntestinal
for the

| for a |

and this
for ay
eg? As
umerols
rited, fot
ald wl
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unt pat
th some
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D of the
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gos,
) hag

Cuap, XXVIII. CONCLUDING REMARKS, 413

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 ag 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 likewise arise through the
law of correlated variation.

Domestic breeds often have an abnormal or semi-monstrous
character, as the Italian greyhound, bulldog, Blenheim 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
structure. We should, however, be cautious in deciding what
deviations ought to be called monstrous: there can hardly be a
doubt that, if the brush of horse-like hair on the breast of the
turkey-cock had first appeared on the domesticated bird, it would
have been considered a monstrosity; 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 oceanieca.

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 reversion 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

414 CONCLUDING REMARKS. Cuap, XXVIII.

intentional selection; more frequently, it is probable, by un-
conscious selection, 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 physical conditions.

It is amuch 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 progenitors 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 structure, which, however, may subse-
quently have been augmented by selection. From what we
know of the history of the racehorse, greyhound, gamecock,
&c., and from their general appearance, we may feel nearly con-
fident 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, sud-
denly appeared in nearly the same state as we now see them.
The frequency 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 instance, without separation
a single monstrous variation would almost certainly be soon

obliterated by crossing.
* On the other hand, we have abundant evidence of the con-
stant occurrence under nature of slight individual differences 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 im-
provement of the racehorse, greyhound, and gamecock. As every
detail of structure in each species is closely adapted to its general

amecock,
arly cop.
yvement:
pigeons,
and, it i
eep, ant
pug-dogs,
ns, hook:
ties, sud:
ee then.
he false
the same
rance,
f abrupt
could le
sparatiol

be 800

Cuap, XXVIII. CONCLUDING REMARKS, 415

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 variations, 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 extent to domestic races; for these, -
if they differ much, generally differ in many respects.

Some naturalists boldly insist! that species are absolutely
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, &e., 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
monuments. 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 historical 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 under-
gone, 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 ad-
mitted 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 com~
bated by Mr. Wallace ;? and full details were given in the thir-
teenth chapter, showing that the tendency to reversion in feral

* Godron, ‘ De l’Espice,’ 1859, tom. ii. p. 44, &e.
* Journal Proce, Linn, Soc., 1858, vol. iii. p. 60.

416 CONCLUDING REMARKS. Cuap. XXVIII,

animals and plants has been greatly exaggerated, though no
doubt to a certain extent it exists. It would be opposed 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 im some manner modified. It should also
be remembered that many characters lie latent in al] organic
beings ready to be evolved under fitting conditions; and in breeds
modified within recent times the tendency to reversion is parti-
cularly strong. But the antiquity of various breeds clearly proves
that they remain nearly constant 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 productions are liable
is strictly limited; but this is an assertion resting on little
evidence. Whether or not the amount in any particular direc-
tion is fixed, the tendency to general variability seems unlimited.
Cattle, sheep, and pigs have been domesticated and have varied
from the remotest period, as shown by the researches of Riiti-
meyer 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-habitations, 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 Hclipse, 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 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 breeders; 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

imited,
| varied
f Riti-

recent
his im
>» know
3 one of
lay new
{ all ox
ns thal
se, or

ould be
D thes?

Cua, XXVIIL CONCLUDING REMARKS. 417

we see in natural species of the variability of extremely modified
parts, that any structure, after remaining constant during a long
series of generations, 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? has
recently 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 between many
domestic breeds, that some few naturalists have concluded that
ail 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 philosophical caution, that they can never admit that one
natural species has given birth to another until they behold all
the transitional steps. But fanciers have used exactly the same
language with tespect 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 “ actually been observed, and can be repeated
“whenever man chooses to set about the task.” No doubt it is
difficult to realise that slight changes added up 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 variability have
been so lately discussed, that T need here only enumerate the
leading points. Ag domesticated organisms are much more

* “The Quarterly Journal of Science,’ Oct. 1867, p. 486.
25

VOL Tay

418 CONCLUDING REMARKS. Cuap, XXVINL

liable to slight deviations of structure and to monstrosities, than
species living under their natural conditions, and as widely-
ranging species vary more than those which inhabit restricted
areas, we may infer that variability mainly depends on changed
conditions 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 reproductive organs more
or less impotent, as shown in the chapter devoted to this sub-
ject; and these organs consequently often fail to transmit faith-
fully 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, independ-
ently of the indirect variability caused by the reproductive
organs being affected, indefinite modifications are the result; in
nearly the same manner as exposure to cold or the absorption
of the same 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 symmetrical and complex out-
growths, 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 ofa gland or other organ, lead to their
increased development. Disuse has a contrary effect. With
domesticated productions organs sometimes become rudimentary
through abortion; but we have no reason to suppose that this
has ever followed from mere disuse. With natural species, on
the contrary, many organs appear to have been rendered rudi-
mentary through disuse, aided by the principle of the economy
of growth, and by the hypothetical principle discussed in the
last chapter, namely, the final destruction of the germs or gem-
mules of such useless parts. This difference may be partly

“S | Cap, XXVIII CONCLUDING REMARKS, 419
thay
Vide). accounted for by disuse having acted on domestic forms for
trict, 1 ar an insufficient length of time, and partly from their exemption
Lange from any severe struggle for existence, entailing rigid economy
ofa in the development of each part, to which all species under
tents * nature are subjected. Nevertheless the law of compensation or
g ba i balancement apparently affects, to a certain extent, our domes-
3 mor I ticated productions. —
nak We must not exaggerate the importance of the definite action
Par | | of changed conditions in modifying all the individuals of the
Hath same species in the same manner, or of use and disuse. Ag
ae every part of the organisation is highly variable, and as varia-
nearly f tions are so easily selected, both consciously and unconsciously,
ecome it is very difficult to distinguish between the effects of the selec-
Dart is tion of indefinite variations, and the direct action of the con-
| CASES, ditions of life. For instance, it is possible that the feet of our
epent- water-dogs, and of the American dogs which have to travel much
luetive _ over the snow, may have become partially webbed from the
ult; in stimulus of widely extending their toes; but it is far more probable
orption that the webbing, like the membrane between the toes of certain
sways ‘Mt pigeons, Spontaneously appeared and was afterwards increased
ene by the best swimmers and the best snow-travellers being’ pre-
mut git served during many generations. A fancier who wished to
use of decrease the size of his bantams or tumbler-pigeons would never
ee. F think of starving them, but would select the smallest indi-
snail viduals which Spontaneously appeared. Quadrupeds are some-
beet times born destitute of hair, and hairless breeds have been
“ist formed, but there is no reason to believe that this is caused bv
- | a hot climate. Within the tropics heat often causes sheep to
Fc lose their fleeces, and on the other hand wet and cold act as a
os ‘ direct stimulus to the growth of hair; it is, however, possible
‘ ie that these changes may merely be an exaggeration of the regular
we yearly change of coat; and who will pretend to decide how far
aptaty this yearly change, or the thick fur of arctic animals, or as
at WP I may add their white colour, ig due to the direct action of a
1e3; é severe climate, and how far to the preservation of the best pro-
rue tected individuals during a long succession of generations ?
Ta | Of all the laws governing variability, that of correlation is
ae | the most important. In Many cases of slight deviations of

es structure as well ag

of grave monstrosities, we cannot eren
422

420 CONCLUDING REMARKS, Cuap. XXVIII.

conjecture what ig the nature of the bond of connexion. But
between homologous parts—between the fore and hind linbs—
between the hair, hoofs, horns, and teeth—we can see that parts
which are closely similar during their early development,
and which are exposed to similar conditions, would be liable to
be modified in the same manner. Homologous paris, from
having the same nature, are apt to blend together, and, when
many exist, to vary in number.

Although every variation is either directly or indirectly caused
by some change in the surrounding conditions, we must never
forget that the nature of the organisation which is acted on essen-
tially 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 manner. We sce 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 analogous or paral-
lel 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 or-
ganisation, through the impaired state of the reproductive
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 accordance with slight differences
in their constitution)—from the effects of the increased or de-
creased use of parts,—and from correlation,—the variability of
our domesticated productions is complicated in an extreme
degree. The whole organisation becomes slightly plastic. Al-
though each modification must have its proper exciting 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 accidental, 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 number of animals of
the same species, allowed to cross freely, with no selection of any

ere Lae

CuaP, XXVIII. CONCLUDING REMARKS, 491

kind; and afterwards to consider the results when selection is
brought into play. Let us suppose that 500 wild rock-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 sup-
pose 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 inhe-
rited; 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 eo on
varying or have recently varied. Many variations 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 seutelle, 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 ske-
leton, such as the sternum and scapule and the feet, would in
egnsequence become slightly reduced in size.
As in our assumed case many birds have to be indiscrimi-
nately killed every year, the chances are against any new
ariety surviving long enough to breed. And as the variations
which arise are of an extremely diversified nature, the chances
are very great against two birds pairing which have varied in
the same manner; nevertheless, a varying bird even when not
thus paired would occasionally transmit its character to its young ;
and these would not only be exposed to the same conditions which
first caused the variation in question to appear, but would in addi-
tion 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

422, CONCLUDING REMARKS,

Cuap. XXVIII,

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 way ; 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 were 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 inclined to admit that the two lots would be
differently modified through the influence of climate and food.
But the evidence on the definite action of changed condi-
tions is in most cases insufficient; and, with respect to pigeons,
I have had the 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
Huropean 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 like-
wise intercross. From the greater vigour and fertility of the
crossed offspring, the whole body would by this means become
interblended sooner than would otherwise have occurred. From
certain breeds being prepotent over others, it does not follow
that the interblended progeny would be strictly intermediate
in character. I have, also, proved that the act of crossing in
itself gives a strong tendency to reversion, so that the crossed
olispring 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.

Cuar, XXVIII. CONCLUDING REMARKS. 493

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 ele-
ments of the same individual habitually acted on each other,
the closest possible interbreeding would be perpetual. There-
fore we should bear in mind that with all hermaphrodite
animals, as far as I can learn, their structure permits and
frequently necessitates a cross with a distinct individual. With
hermaphrodite plants we incessantly meet with elaborate and
perfect contrivances for this same end. It is no exaggeration —
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, we may with equal safety infer that many flowers
are constructed for the express purpose of ensuring a cross with
a distinct plant. From these various considerations, the con-
clusion arrived 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.

Yo return to our illustration: we have hitherto assumed that
the birds were kept down! to the same number by indiscriminate
slaughter; but if the least choice be permitted in their preser-
vation and slaughter, the whole result 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 surprisingly 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 continually pre-
serving the most strongly marked individuals, to increase the
amount of difference up to a high, predetermined 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 modity his

424

CONCLUDING REMARKS, Cuar. XXVIII.

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 characters, and the two lots would ultimately come
to differ. This has actually occurred with strains or families
of catile, sheep, and pigeons, which have been long kept and
eareiully attended to by different breeders without any wish
on their part to form new and distinct sub-breeds. This uncon-
scious kind of selection will more especially come into
with animals which are highly serviceable 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 any one 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 worst 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 the transmis-
sion, of all sorts of trifling peculiarities of character. The same
process will have been pursued with our fruit-trees and vege-
tables, for the best will always have been the most largely cul-
tivated, and will occasionally have yielded seedlings better than
their parents.

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 move
important results than methodical selection, and is likewise more
important under a theoretical point of view from closely resem-
bling 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 succession
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 struc-

action

Cuap, XXVIII. CONCLUDING REMARKS, 495,

ture. 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 selection will probably play a
more important part. Hence such animals often closely re-
semble 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 extremes, to produce
each character more and more strongly pronounced, there is a
constant tendency in every breed, through the prolonged action
of methodical and unconscious selection, to become more and
more different from its parent-stock; and when several breeds
have been produced and are yalued for different qualities, to
differ more and more from each other. This leads to Divergence
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 locality, close interbreeding, by lessening their
vigour and fertility, aids in their final extinction. Thus the
intermediate links are lost, and breeds which have already
diverged gain Distinctness of Character.

Tn the chapters on the Pigeon, it was proved by historical
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 do-
mestic breeds, as of the Irish wolf-dog, the old English hound,
and of two breeds in France, one of which was formerly highly
valued* Mr. Pickering remarks® that “the sheep figured on
“ the most ancient Egyptian monuments is unknown at the pre-
“sent 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 ancient inhabitants of Europe during the neolithic period.
In Peru, Von Tschudi ® 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 culinary vegetables,

: M. Rufz de Lavison, in « Bull, Soc. Imp. d’Acclimat.,’ Dec. 1862, p, 1009.
* ‘Races of Man,’ 1850, p. 315, 6 * Travels in Peru,’ Eng. translat., p. 177.

436 CONCLUDING REMARKS. Cuap. XXVIII.

the production of new varieties and their extinction has in-
cessantly recurred. At the present time improved breeds some-
times displace at an extraordinarily 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 by some murderous pestilence,” by the introduction
of Short-horns.’

What grand results have followed from the long-continued
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 which
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 cannot 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 pre-
served a pigeon with its oesophagus 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 whole structure ad-
mirably 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 excellence, should simultaneously arise and be selected.
Although 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 plant, is most valued by
man, that part or quality differs most in the several races.
This result is well seen by comparing the amount of difference

7 Youatt on Cattle, 1834, p. 200: on Pigs, see ‘ Gard. Chronicle,’ 1854, p. 410.

Cap, XXVIIL CONCLUDING REMARKS, | 427

between the fruits produced by the varieties of the same fruit-
tree, between the flowers of the varieties in our flower-garden,
between the seeds, roots, or leaves of our culinary and agricul-
tural plants, in comparison 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,’ namely, that
the seeds of a large number of plants,—wheat, barley, oats, peas,
beans, lentils, poppies,—cultivated for their seed by the ancient
Lake-inhabitants of Switzerland, were all smaller than the seeds
of our existing varieties. NRiitimeyer 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 Denmark during the Bronze
period had extraordinarily slender limbs, and the horse was
smaller than our present animal.? 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 eradually im-
proved in different parts of the great Europmo-Asiatic conti-
nent, 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, park-cattle, and boars,!° 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
petseverance,—facility in matching or separating animals,—and
especially a large number being kept, so that the inferior
individuals may be freely rejected or destroyed, and the better
ones preserved. When many are kept there will also be a

* “Die Pflanzen der Pfahlbauten,’ Mars, 1860, p. 298.

ye # 10 Riitimeyer, ‘Die Fauna der Pfahl-
Morlot, ‘Soc. Vaud. des Scien. Nai’ bauten,’ 1861, s. 30.

428 CONCLUDING REMARKS. Cuap. XXVIII.

greater chance of the occurrence of well-marked deviations of
structure. Length of time is all-important; for as each cha-
racter, in order to become strongly pronounced, has to be
augmented by the selection of successive variations of the same
nature, this can only be effected during a long series of gene-
rations. Length of time will, also, allow any new feature to
become fixed by the continued rejection 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
animals 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 brecds.
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
animals with unusual care, and after a time a slight difference is
perceived by his neighbours ;—the difference goes on being aug-
mented 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 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, inducing 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 certain 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 monuments, with the solid-
hoofed swine mentioned by Aristotle, with five-toed fowls de-

11 Godron, ‘ De ’Espéce,’ tom. i., 1859, p. 368.

a |
ee

Guar. XXVIII. CONCLUDING REMARKS. 499

scribed 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
doubtful whether any are identically the same with our present
breeds. A great mastiff sculptured on an Assyrian tomb, 640 3.¢.,
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
eround-tumbler.

De Candolle * has fully discussed the antiquity of various
races of plants; he states that the black-seeded poppy was
known in the time of Homer, the white-seeded sesamum by the
ancient HKgyptians, and almonds with sweet and bitter 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, both of which were cul-
tivated at an immensely remote period by the Lake-inhabitants
of Switzerland, still exist. It is said™ 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."

In accordance with the views maintained by me in this work
and elsewhere, not only the various domestic races, but the

® ©Géographie Botan.,’ 1855, p. 989. 14 ¢ Journal of a Horticultural Tour,’

8 Pickering, ‘Races of Man,’ 1850, bya Deputation of the Caledonian Hist.
p. 318. Soc., 1823, p. 293.

439 CONCLUDING REMARKS. Cuap, XXVUL.

most distinct genera and orders within the same great class,—
for instance, whales, mice, birds, and fishes—are all the descend-
ants 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 sub-
ject under this point of view is enough to strike one dumb
with amazement. 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 that each
slight modification of structure which was in any yay benefi-
cial under excessively complex conditions of life, will have »
been preserved, whilst each which was in any way injurious
will have been rigorously destroyed. And the long-continued
accumulation of beneficial variations will infallibly lead to
structures as diversified, as beautifully 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 domestic breeds, or by nature to the produc-
tion of species. I may recur to the metaphor given in a former
chapter: if an architect were to rear a noble and commodious
edifice, 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 indis-
pensable to the architect, bear to the edifice built by him the
same relation which the fluctuating variations of each organic
being bear to the varied and admirable structures ultimately
acquired by its modified descendants.

Some authors have declared that natural selection explains
nothing, unless the precise cause of each slight individual dif-
ference be made clear. Now, if it were explained to a savage
utterly ignorant of the art of building, 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

CuaP, XXVIII. CONCLUDING REMARKS. 431

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 being.

The shape of the fragments of stone at the base of our pre-
cipice 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 lincs
of deposition or cleavage, on the form of the mountain which
depends on its upheaval and subsequent denudation, and lastly.
on the storm or earthquake which threw down the fragments.
But in regard to the use to which the fragments may be 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 consequence 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
if ee,

should assume certain 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 animals and plants ;—
many of these variations being of no service to man, and not
beneficial, far more often injurious, 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 we give up the principle
in one case,—if we do not admit that the variations of the pri-
meval dog were intentionally guided in order that the erey-
hound, for instance, that perfect image of symmetry and
vigour, might be formed,—no shadow of reason can be assigned
for the belief that variations, alike in nature and the result

432 CONCLUDING REMARKS. Cuap, XXVIII.

of the same general laws, which have been the eroundwork
through natural selection of the formation of the most per-
fectly adapted animals in the world, man included, were inten-
tionally and specially guided. However mtch we may wish
it, we can hardly follow Professor Asa Gray in his belief “that
“ variation has been led along certain beneficial 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 injurious deviations of structure, as well as that
redundant power of reproduction which inevitably leads to a
struggle 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 omnipotent and omni-
scient 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,

Axspas Pacha, a fancier of fantailed pi-
geons, i. 206.

Axpey, Mr., on grafting, ii. 147 ; on mig-
7

nonette, ii, 237.

Axporr, Mr. Keith, on the Persian tum-
bler pigeon, i. 150.

ABBREVIATION of the facial bones, i. 73.

ABORTION of organs, li. 315-318, 397.

AxsorpTion of minority in crossed races,
li. 87-89, 174.

ACCLIMATISATION, ii. 305-315; of maize,
1, 322.

Acerst, on the fertility of domestic ani-
mals ini Lapland, ii. 112,

Achatinella, ii. 53.

Achillea millefolium, bud variation in, i.
408.

Aconitum napellus, roots of, innocuous in
cold climates, ii. 274.

Acorus calamus, sterility of, ii. 170.

Acosta, on fowls in South America at its
discovery, i. 237,

Acropera, number of secds in, ii. 379,

Avam, Mr., origin of Oytisus Adami, i.
390.

Apam, W., on consanguineous marriages,
li. 123.
Apams, Mr., on hereditary diseases, ii. 7.
ADVANCEMENT in scale of organisation,
we
Aigilops triticoides, observations of Fabre
and Godron on, i. 313; increasing fer-
tility of hybrids of, with wheat, ii. 110,
AR sculus flava and rubicunda, i. 392.
Aisculus pavia, tendency of, to become
double, ii. 168.
Aithusa cynapium, ii. 837.
AFFINITY, sexual elective, ii, 180.
Arrica, white bull from, i. 91: feral cattle
in, i. 85; food-plants of savages of, i.
307-309 ; South, diversity of breeds of
cattle in, i. 80; West, change in fleece
of sheep in, i. 98.
Agave vivipara, seeding of, in poor soil,
ii. 169.
Agu, changes in trees, dependent on, i.
387.

Acoutr, fertility of, in captivity, ii, 152,
AGRICULTURE, antiquity of, ii, 243,
Agrostis, seeds of, used as food, i, 309,

AGUARA, i. 26,
VOLE Le

AMYGDALUS.

Arnswortu, Mr., on the change in the
hair of animals at Angora, ii. 278,

Axzar Khan, his fondness for pigeons, i.
205 ; ii, 204.

Alauda arvensis, ii. 154.

ALBIN, on “ Golden Hamburgh ” fowls, i.
247; figure of the hook-billed duck, i.
277.

ALBINISM, i. 111, ii. 17.
ALBINO, negro, attacked by insects, ii.

229

Axprnoss, heredity of, ii. 9.

Atsinvs, thickness of the epidermis on
the palms of the hands in man, ii. 297,

Aco, 1. 31, ii. 102.

ALDROVANDI, on rabbits, i. 104: descrip-
tion of the nun pigeon, i. 156; on the
fondness of the Dutch for pigeons in
the seventeenth century, i. 205; notice
of several varieties of pigeons, i. 207-
210; on the breeds of fowls, i. 247; on
the origin of the domestic duck, i. 278,

ALEFIELD, Dr., on the varieties of peas
and. their specific unity, i. 326; on the
varieties of beans, i. 330.

ALEXANDER the Great, his selection of
Indian cattle, ii, 202.

ALG, retrogressive metamorphosis in, ii.
361; division of zoospores of, ii. 378,
ALLEN, W., on feral fowls, i. 237; ii. 33.
ALLMAN, Professor, on a monstrous Sazi-
fraga geum, ii. 166; on the develop-

ment of the Hydroida, ii. 368.

ALmonD, i. 337; antiquity of, ii. 429;
bitter, not eaten by mice, ii. 232.

Alnus glutinosa and incana, hybrids of,
ii. 130.

ALPaca, selection of, ii. 208,

Althza rosea, i. 378, ii. 107.

Amaryllis, ii. 139, .

Amaryllis vittata, effect of foreign pollen
on, i. 400.

Amavrosis, hereditary, ii. 9.

America, limits within which no useful
plants have been furnished by, i. 310:
colours of feral horses in, i. 60-61 :
North, native cultivated plants of, i.
312; skin of feral pig from, i. 77;
South, variations in cattle of, i, 88,
92

Amygdalus persica, i. 336-344, 374,
2F

434.

~“

AMMON,

INDEX.

ARISTOTLE.

Ammon, on the persistency of colour in
horses, ii. 21.

Anagallis arvensis, ii. 190.

ANALOGOUS variation, i. 409, ii. 348-352 ;
in horses, i. 55; in the horse and ass, i.
64; in fowls, i. 243-246.

Anas boschas, i, 277, ii. 40; skull of,
figured, i. 282.

Anas moschata, i. 181; ii. 40.

“ ANcon” sheep of Massachusetts, i. 100,
ii. 103.

ANDALUSIAN fowls, i. 227.

ANDALUSIAN rabbits, i. 105.

Anpberson, J., on the origin of British
sheep, i. 94; on the selection of qualities
in cattle, ii. 196; on a one-eared breed
of rabbits, i.108; on the inheritance of
characters from a one-eared rabbit and
three-legged bitch, ii. 12; on the per-
sistency of varieties of peas, 1.329; on
the production of early peas by selec-
tion, ii. 201; on the varieties of the
potato, i. 8330-331 ; on crossing varieties
of the melon, i. 399; on reversion in
the barberry, i. 384.

AnpeErson, Mr., on the reproduction of the
“weeping ash by seed, ii. 19; on the cul-
tivation of the tree peeony in China, ii.
205.

Anpersson, Mr., on the Damara, Bechu-
ana, and Namaqua cattle, i. 88; on the
cows of the Damaras, ii. 300; selection
practised by the Damaras and Nama-
quas, ii. 207; on the use of grass-seeds
and the roots of reeds as food in South
Africa, 1. 309.

Anemone coronaria, doubled by selection,
ii. 200.

Anerna pectoris, hereditary, occurring at
a certain age, ii. 79.

ANGLESEA, Cattle of, i. 80.

ANGOLA sheep, i. 95.

ANGorA, change in hair of animals at, ii.
278; cats of, i. 45, 47; rabbits of, 1.
106, 120.

Anmats, domestication of, facilitated by
fearlessness.of man, i. 20; refusal of
wild, to breed in captivity, ii. 149;
compound, individual peculiarities of,
reproduced by budding, i. 374; varia-
tion by selection in useful qualities of,
ii, 220,

AnnvaL plants, rarity of bud-variation
in, i. 408.

Anomattss in the osteology of the horse,
i. 50.

Anomatovs breeds of pigs, i. 75 ; of cattle,
i. 89.

Anser albifrons, characters of, reproduced
in domestic geese, i. 288.

Anser xgyptiacus, i. 282; ii, 68.

Anser canadensis, ii, 157.

Anser cygnoides, i. 237.

Anser ferus, the original of the domestic
goose, i. 287; fertility of cross of, with
domestic goose, i. 288.

Anson, on feral fowls in the Ladrones, i.
238.

ANTAGONISM between growth and repro-
duction, ii. 384.

Anthemis nobilis, bud-variation in flowers
of, i. 879; becomes single in poor soil,
ii. 167.

ANTHEROZOIDS, apparent independence
of, in algee, ii. 884.

AntTHERS, contabescence of, ii. 165-166.

ANTIGUA, cats of, i. 46; changed fleece of
sheep in, i. 98.

Antirrhinum majus, peloric, i.365; ii. 59,
70, 166 ; double-flowered, ii. 167; bud-
variation in, i. 381,

Ants, individual recognition of, ii. 251.

Args, anthropomorphous, ii. 123.

Aprupes, attacking pear-trees, ii. 231;
development of, ii. 361-362.

APopLExy, hereditary, occurring at a cer-
tain age, ii. 78.

APPLE, i. 348-350; fruit of, in Swiss lake-
dwellings, i. 317; rendered fastigate
by heat in India, i. 8361; bud-variation
in the, i. 376; with dimidiate fruit, i.
892-393; with two kinds of fruit on
the same branch, i, 392; artificial fe-
cundation of, i. 401; St. Valery, i. 401;
ii. 166; reversion in seedlings of, ii.
31; crossing of varieties of, ii. 129;
growth of the, in Ceylon, ii. 277 ; Winter
Majetin, not attacked by coccus, il. 231;
flower-buds of, attacked by bullfinches,
ii. 232; American, change of when
grown in England, ii. 275.

Apricot, i. 844-345; glands on the leaves
of, ii. 231; analogous variation in the,
ii. 348,

Aquila fusca, copulating in captivity, il.
154.

Aquilegia vulgaris, i. 365; ii. 330.

Aras boarhound, described by Harcourt,
Rote

Arabis blepharophylla and A. Soyer,
effects of crossing, i, 400.

Aralia trifoliata, bud-variation in leaves
of, i. 382. ;

ARAUCARIAS, young, variable resistance
of, to frost, i1. 309.

ARCHANGEL pigeon, ii. 240.

Arctic regions, variability of plants and
shells of, ii. 256. :

Aria vestita, grafted on thorns, 1. 387.

AnisTopHants, fowls mentioned by, i. 246.

Anrrstorie, on solid-hoofed pigs, i. 79;
domestic duck unknown to, i. 277; on
the assumption of male characters by
old hens, il. d1.

-
a. aa

Sees

;
:
.
;
;

ARNT. INDEX. BARB. 435

ARNI, domestication of the, i. 82.

Arrest of development, ii. 315-318.

ARTERIES, increase of anastomosing
branches of, when tied, ii. 230.

Anu islands, wild pig of, i. 67.

ArvM, Polynesian varieties of, ii, 256,

Ascaris, number of eggs of, ii. 379.

Asu, varieties of the, i. 360; weeping, i.
361; simple-leaved, i. 362; bud-varia-
tion in, i. 382; effects of graft upon the
stock in the, i. 394; production of the
blotched Breadalbane, ibid.; weeping,
capricious reproduction of, by seed,
ii. 19.

Asinus Burchellii, i. 64.

Asinus hemionus, ii. 43.

Asinus indicus, ii. 42-43, 48.

Asinus quagga, i. 64. ;

Asinus teniopus, ii. 41; the original of
the domestic ass, i. 62.

AsparaGus, increased fertility of culti-
vated, ii. 113.

Ass, early domestication of the, i. 62;
breeds of, ibid. ; small size of, in India,
ibid.; stripes of, i. 62-63; ii. 351; dis-
like of to cross water, i. 181; reversion
in, ii. 41-43, 47; hybrid of the, with
mare and zebra, ii. 42; prepotency of
the, over the horse, ii. 67-68; crossed
with wild ass, ii. 206; variation and
selection of the, ii, 236.

ASSYRIAN sculpture of a mastiff, i. 17.

ASTERS, ii. 20, 316.

Astrum, hereditary, ii. 8, 79.

Aravism. See Reversion.

ATHELSTAN, his care of horses, ii. 203.

Arktnson, Mr., on the sterility of the
Tarroo silk-moth in confinement,, ii.
157.

AUBERGINE, ii. 91.

AUDUBON, on feral hybrid ducks, i. 190:
ii. 46; on the domestication of wild
ducks on the Mississippi, i. 278; on the
wild cock turkey visiting domestic
hens, i. 292; fertility of Fringilla ciris
in captivity, ii. 154; fertility of Columba
migratoria and leucocephala in cap-
tivity, ii. 155; breeding of Anser cana-
densis in captivity, ii. 157.

Avpvupon and Bachman, on the change
of coat in Ovis montana, i. 99; ste-
rility of Sctwrus cinerea in confinement,
ii. 152,

Avricua, effect of seasonal conditions
on the, ii. 273; blooming of, ii, 346.
AUSTRALIA, no generally useful plants
derived from, i. 310; useful plants of,

enumerated by Hooker, i. 311.

Avsrrra, heredity of character in em-

» perors of, li. 65.

AUTENRIETH, on persistency of colour in
horses, ii, 21,

Rs oe as een
Ava, horses of, i. 53.
Avena fatua, cultivability of, i. 318.
AyrEN Akbery, pigeons mentioned in
the, i, 150, 155, 185, 205, 207, 208.
Ayres, W. P., on bud-variation in pelar-
goniums, i. 378, :
Azalea indica, bud-variation in, i, 877,
AzaRA, on the feral dogs of La Plata, i. 27;
on the crossing of domestic with wild
cats in Paraguay, i. 45; on hornlike
processes in horses, i. 50; on curled
hair in horses, i. 54; ii, 205, 325;
on the colours of feral horses, i. 60, 61;
ii. 259; on the cattle of Paraguay and
La Plata, i. 82, 86, 89; ii. 259; on a
hornless bull, ii. 205; on the increase
of cattle in South America, ii. 119 ; on
the growth of horns in the hornless
cattle of Corrientes, ii. 89: on the
“ Niata” cattle, i. 90; on naked quad-
rupeds, ii. 279; on a race of black-
skinned fowls in South America, i.
258; ii. 209; on a variety of maize, i,
321.

Bazrnaton, C. C., on the origin of the
plum, i. 345; British species of the
genus Rosa, i. 366; distinctness of
Viola lutea and tricolor, i. 368.

Bacumann, Mr., on the turkey, ii, 262.
See also Audubon.

Bancer, breeding in confinement, ii. 151.

“* BAGADOTTEN-T'AuBE,”’ i, 141.

Bainy, Mr., on the effect of sclection on
fowls, ii, 198; on Dorking fowls, ii,
238.

Barr, 8., on the origin of the turkey, i.
292.

Baker, Mr., on heredity in the horse, ii.
11; on the degeneration of the horse
by neglect, ii. 239; orders of Henrys
VII. and VIII. for the destruction of
undersized mares, ii. 203.

BakEwELL, change in the sheep effected
by, ii. 198.

BaLANCeMENT, ii, 342-344; of growth,
law of, 274,

BALDHEAD; pigeon, i. 151.

Baupness, in man, inherited, ii. 73-74;
with deficiency in teeth, ii. 326-327.
Bauuance, Mr., on the effects of inter-
breeding on fowls, ii. 125; on varia-

tion in the eggs of fowls, i. 248.

Ballota nigra, transmission of variegated
leaves in, i. 383.

Bampoo, varicties of the, ii. 256.

BANANA, variation of the, i. 372; ii. 256,
258; bud-variation in the, i. 377; ste-
rility of the, ii. 268,

Bantam fowls, i. 230; Sebright, origin
of, ii. 96; sterility of, ii. 101.

Bans (Pigeon), i, 144-146, 210; ii. 227;

2F2

436

BARBS,

INDEX.

BEET.

figure of, i. 145; figure of lower jaw of,
i. 164,

Barps, of wheat, i. 314.

Barperry, dark or red-leaved variety, i.
362; ii. 19; reversion in suckers of
seedless variety, i. 384,

Barsot, J., on the dogs of Guinea, i. 25;
on the domestic pigeons in Guinea, i.
186 ; fowls not native in Guinea, i. 237.

BarkKING, acquisition of the habit of, by
various dogs, i. 27,

Bak ey, wild, i. 313; of the lake-dwel-
lings, i. 317-318; ancient variety of,
ii. 429.

Barnegs, Mr., production of early peas by
selection, ii. 201.

Barnet, Mr., on the intercrossing of straw-
berries, i. 351; diceciousness of the
Hautbois strawberry, i. 353; on the
scarlet American strawberry, li. 200.

Barts, Dr., use of grass-seeds as food in
Central Africa, i. 308.

Baxrrierr, A. D., on the origin of “ Hi-

~ malayan” rabbits by intercrossing, i.
109; on the feral rabbits of Porto
Santo, i. 114; on geese with reversed
feathers on the head and neck, i. 288;
on the young of the black-shouldered
peacock, i. 290; on the breeding of the
Felide in captivity, ii. 150.

Bartram, on the black wolf-dog of Flo-
rida, i. 22.

Bates, H. W., refusal of wild animals to
breed in captivity, ii. 150, 152; sterility
of American monkeys in captivity,
ii. 153; sterility of tamed guans, ii.
156. ;

Barracuta, regeneration of lost parts in,
ii. 15.

Bracg, raised, in Peru, containing heads
of maize, i. 320.

Brak, variability of, in fowls, i. 258; in-
dividual differences of, in pigeons, i.
160; correlation of, with the feet in
pigeons, i, 171-174.

Brae, Lionel, on the contents of cells,
ii. 370; on the multiplication of infec-
tious atoms, ii. 378; on the origin of
fibres, ii. 382.

Beans, i. 330; of Swiss lake-dwellings, i.
319; varieties of, produced by selec-
tion, ii, 218; French and scarlet, va-
riable resistance of to frost, ii. 309,
314; superiority of native seed of, il.
314; a symmetrical variation of scarlet,
ii. 8322 ; experiments on kidney, i. 330 ;

_ with monstrous stipules and abortive
leaflets, ii. 343.

Brarp, pigeon, i. 151.

Bears, breeding in captivity, ii. 151.

Buastey, J., reversion in crossed cattle,
ii. 41,

Braton, D., effect of soil upon strawber-
ries, i. 353; on varieties of pelargo-
nium, i. 364, ii. 274, 311; bud-varia-
tion in Gladiolus colvillii, i. 382; cross
between Scotch kail and cabbage, ii.
98; hybrid gladiolus, ii. 139 ; constant
occurrence of new forms among seed-
lings, ii. 235; on the doubling of the
compositee, ii. 316.

Brcuuana cattle, i. 88.

Beck, Mr., constitutional differences in
pelargoniums, i. 364.

Beckmann, on changes in the odours of
plants, ii. 274.

Brcustrern, on the burrowing of wolves,
i. 27; “Spitz” dog, i. 31; origin of
the Newfoundland dog, i. 42; crossing
of domestic and wild swine, i. 66; on
the Jacobin pigeon, i. 154, 209; notice
of swallow-pigeons, i. 156; on a fork-
tailed pigeon, i. 157; variations in the
colour of the croup in pigeons, i. 184 ;
on the German dove-cot pigeon, i. 185;
fertility of mongrel pigeons, i. 192; on
hybrid turtle-doves, i. 193 ; on crossing
the pigeon with Columba cnas, C. pa-
lumbus, Turtur risoria, and T. vulgaris,
i. 193; development of spurs in the
silk-hen, i. 256; on Polish fowls, i.
257, 264; on crested birds, i. 257; on
the Canary-bird, i. 295, ii. 22, 161;
German superstition about the turkey,
i. 293; occurrence of horns in hornless
breeds of sheep, ii. 30; hybrids of the
horse and ass, ii. 68; crosses of tail-
less fowls, ii. 92; difficulty of pairing
dove-cot and fancy pigeons, ii. 103;
fertility of tame ferrets and rabbits, ii.
112; fertility of wild sow, ¢bid. ; diffi-
culty of breeding caged birds, ii. 154 ;
comparative fertility of Psittacus eri-
thacus in captivity, li. 155; on changes
of plumage in captivity, ii, 158; lia-
bility of light-coloured cattle to the
attacks of flies, ii. 229; want of exer-
cise a cause of variability, ii. 257; effect
of privation of light upon the plumage
of birds, ii. 280; on a sub-variety of
the monk-pigeon, ii. 350.

Buppor, Dr., correlation of complexion
with consumption, ii. 339,

BeEpeEGuar gall, ii. 284.

Ber, persistency of character of, ii. 236,
254; intercrossing, ii. 126; conveyance
of pollen of peas by, i. 829.

Brr-Orurys, self-fertilisation of, ii. 91.

Brxcu, dark-leaved, i. 362, ii. 19; fern-
leaved, reversion of, i. 882; weeping,
non-production of by seed, ii. 19.

Burcury, horses of Loochoo Islands, i. 93.

Beet, i. 326; increase of sugar in, b
selection, ii. 201,

BEGONIA.

INDEX. BLYTH, 437

Begonia frigida, singular variety of, i.
365; sterility of, ii. 166.

BrELGIAN rabbit, i. 106.

Beit, T., statement that white cattle
have coloured ears, i. 85.

Bexzt, W., bud-variation in Cistus tri-
cuspis, i. 377, ;
BELLINGERI, observations on gestation in
the dog, i. 30; on the fertility of dogs

and cats, ii. 112.

Beton, on high-flying pigeons in Paphla-
gonia, i, 209; varieties of the goose, i.
289.

BENGUELA, cattle of, i. 88,

Bennett, Dr. G., pigs of the Pacific
islands, i. 70, 87; dogs of the Pacific
islands, i. 87; varieties of cultivated
plants in Tahiti, i. 256,

Bennett, Mr., on the fallow deer, ii. 103.

Bentuam, G., number and origin of cul-
tivated plants, i. 306; cereals all cul-
tivated varieties, i. 312; species of the
orange group, i. 834-335 ; distinctions
of almond and peach, i. 338; British
species of Rosa, i. 366; identity of
Viola lutea and tricolor, i. 368.

Berberis vulgaris, i. 384, ii. 19.

Berberis Wallichii, indifference of, to cli-
mate, ii. 164. .

Brpsean, on the history of the dog, i. 16,
18.

Berxevey, G. F., production of hen-
cocks in a strain ot game-fowls, i. 253.
Berxevey, M. J., crossing of varieties of
the pea, i. 397; effect of foreign pollen
on grapes, i. 400; on hybrid plants, ii.
131; analogy between pollen of highly-
cultivated plants and hybrids, ii. 268;
on Hungarian kidney-beans, ii. 275;
failure of Indian wheat in England, ii.
307; bud developed on the petal of a

Clarkia, ii. 384.

Brrnarp, inheritance of disease in the
horse, ii. 10. -

Bernarp, C., independence of the organs
of the body, ii. 368-369; special affi-
nities of the tissues, ii. 380.

Bernuarvt, varieties of plants with laci-
niated leaves, li. 348.

Bernicla antarctica, i. 288.

Brrrero, on feral pigeons in Juan Fer-
nandez, i. 190.

Betula alba, ii. 18.

Bewicr, on the British wild cattle, i. 84,

Bisie, reference to breeding studs of
horses in, i. 54; references to domestic
pigeons in the, i. 205; indications of
selection of sheep in the, ii. 201; notice
of mules in the, 1i. 202.

Bipwew, Mr., on self-impotence in Ama-
ryllis, il. 139.

Bincu, weeping, i. 387, ii. 18.

Brrcu, Dr. §., on the ancient domestica-
tion of the pigeon in Egypt, i. 205; no-
tice of bantam fowls in a Japanese
encyclop:edia, i. 230, 247,

Brrcn, Wyrley, on silver-grey rabbits, i,
109-110.

Birps, sterility caused in, by change of
conditions, ii. 153-157.

BLADDER-NUT, tendency of the, to become
double, ii. 168.

a Mr., on wry-legged terriers, ii.

BLAINVILLE, origin and history of the
dog, i. 15-16 ; variations in the number
of teeth in dogs, i. 34; variations in the
number of toes in dogs, i. 35 ; on mum-
mies of cats, i. 43; on the osteology of
solid-hoofed pigs, i.75; on feral Pata-
gonian and N, American pigs, i. 77.

“ Buass-TAuBE,” i. 156,

BieEpineG, hereditary, ii. 7, 8; sexual
limitation of excessive, ii. 73.

Bienpine of crossed races, time occupied
by the, ii. 87,

Buinpngss, hereditary, ii. 9; at a certain
age, li. 78; associated with colour of
hair, ii, 328,

Bioopuounns, degeneration of, caused by
interbreeding, ii. 121.

Biumensacn, on the protuberance of the
skull in Polish fowls, i. 257; on the
effect of circumcision, ii, 23; inheri-
tance of a crooked finger, ii. 23; on
badger-dogs and other varieties of the °
dog, ii. 220; on Hydra, ii. 293; on the
“nisus formativus,” ii. 294.

Buyrtn, E., on the Pariah dog, i. 24; hy-
brids of dog and jackal, i. 32; early
domestication of cats in India, i. 43;
origin of domestic cat, 7b. ; crossing of
domestic and wild cats, i. 44; on Indian
cats resembling Felis chaus, i. 45; on
striped Burmese ponies, i. 58; on the
stripes of the ass, 1.63; on Indian wild
pigs, i. 66 ; on humped cattle, i. 79, 80;
occurrence of Bos frontosus in Irish

- crannoges, 1. 81; fertile crossing of
zebus and common cattle, i. 83; on
the species of sheep, i. 94; on the fat-
tailed Indian sheep, i. 96; origin of the
goat, i. 10L; on rabbits ‘breeding in
India, i. 112 : number of tail-feathers
in fantails, i. 146; Lotan tumbler pi-
geons, i. 150; number of tail-feathers
in Hetopistes, i. 159; on Columba affinis,i.
183 ; pigeons roosting in trees, 1. 181;
on Columba leuconota, i. 182; on Co-
lumba intermedia of Strickland, i. 184;
variation in colour of croup in pigeons,
i, 184-185, 197; voluntary domestica-
tion of rock-pigeons in India, i. 185;
feral pigeons on the Hudson, i. 190;

438

BOETHIUS,

INDEX.

BRAUN,

occurrence of sub-species of pigeons, i.
204; notice of pigeon-fanciers in Delhi,
&e., 1. 206 ; hybrids of Gallus Sonneratii
and the domestic hen, i. 234 ; supposed.
hybridity of Gallus Temminckii, 1. 235 ;
variations and. domestication of Gallus
bankiva, i. 235-236, 237; crossing of
wild and tame fowls in Burmah, i. 236;
restricted range of the larger gallina-
ceous birds, i. 237; feral fowls in the
Nicobar islands, i. 238; black-skinned
fowls occurring near Calcutta, i. 256;
weight ‘of Gallus bankiva, i. 272; de-
generation of the turkey in India, i.
294, ii. 278; on the colour of gold-fish,
i. 296; on the Ghor-Khur (Asinus in-
dicus), li. 42; on Asinus hemionus, ii.
43; number of eggs of Gallus bankiva,
ii. 112; on the breeding of birds in cap-
tivity, ii. 157; co-existence of large and
small breeds in the same country, ii.
279; on the drooping ears of the ele-
phant, ii. 301; homology of leg and
wing feathers, ii. 323.
Boerrutus on Scotch wild cattle, i. 85.
Borrarp and Corbié, on the breeds of pi-
geons, 1. 132; Lille pouter pigeon, i.
138; notice of a gliding pigeon, i. 156;
variety of the pouter pigeon, i. 162;
dove-cot pigeon, i. 185; crossing pigeons,
i. 192-193, ii. 97, 126; sterility of hy-
brids of turtle-doves, i. 193; reversion
of crossed pigeons, i. 197, ii. 40; on
the fantail, i. 208, ii. 66; on the trum-
peter, ii. 66; prepotency of transmis-
sion in silky fantail, ii. 67, 69; secon-
dary sexual characters in pigeons, ii.
74; crossing of white and coloured
turtle-doves, ii. 92; fertility of pigeons,
li 12:
Bompycrp®, wingless females of, ii. 299.
Bombyx hesperus, ii. 304,
Bombyx Huttoni, i. 302.
Bombyx mori, i. 8300-304.
BonaFovs, on maize, i. 320, 321.
Bonaparte, number of species of Colum-
‘bide, i. 183; number of tail-feathers
in pigeons, 1.158; size of the feet in
Columbide, i. 174; on Columba guinea,
i. 182 ; Columba turricola, rupestris, and
Schimperi, i. 184.
Bonatea speciosa, development of ovary
- of, 1. 403. ae
Bonavia, Dr., growth of cauliflowers in
India, ii. 310.
Bonss, removal of portions of, ii. 296;
regeneration of, ii. 294; growth and
repair of, ii, 881-382.
Bonnet, on the salamander, ‘ii. 15, 341,
358, 385 ; theory of reproduction, ii. 385.
Borcumeyer, experiments with the seeds
of the weeping ash, ii, 19.

Borxcoxe, i. 323.

Borex, on Polish fowls, i. 247.

Borneo, fowls of, with tail-bands, 1. 235.

Bornet, E., condition of the ovary in hy-
brid Cisti, i. 889; self-impotence of
hybrid Céstz, ii. 140.

Borrow, G., on pointers, i. 42.

Bory de Saint-Vincent, on gold-fish,i. 297.

Bos, probable origin of European domestic
cattle from three species of, i. 83.

Bos frontosus, i. 79, 81-82.

Bos indicus, i. 79.

Bos longifrons, i. 79, 81.

Bos primigenius, i. 79-81, 119,

Bos sondaicus, ii. 206.

Bos taurus, 1. 79.

Bos trochoceros, i. 81,

Bosc, heredity in foliage-varietics of the
elm, i. 362.

Bosse, production of double flowers from
old seed, ii. 167.

Bosst, on breeding dark-coloured silk-
worms, 1. 302.

BovcHarDAT, on the vine disease, i. 334.

Bounty, on local diseases, ii. 276; resis-
tance to cold of dark-complexioned
men, ii. 335.

** BOuLANS,” i. 187.

“ Bouron d’Alep,” ii. 276.

Bowen, Prof., doubts as to the importance
of inheritance, ii. 3.

BowerBank, Dr., on the effects of a first
impregnation, i. 404.

Bowman, Mr., hereditary peculiarities in
the human eye, ii. 8-10; hereditary
cataract, ii. 79.

Brace, Mr., on Hungarian cattle, i. 80.

Brachycome iberidifolia, ii. 261.

Bracts, unusual development of, in goose-
berries, i. 355.

Brav.ey, Mr., effect of grafts upon the
stock’ in the ash; i. 394; effect of
foreign pollen upon apples, i. 401; on
change of soil, ii. 146.

“ BranMa Pootras,” a new breed of fowls,
i. 245,

Bratn, proportion of, in hares and rabbits,
i, 126-129.

BraAnvrt, origin of the goat, i. 101.

Brassica, varieties of, with enlarged stems,
ii. 348.

Brassica asperifolia, ii. 343,

Brassica napus, i. 325.

Brassica oleracea, i. 323.

Brassica rapa, i. 825, ii. 165. wie

Brawn, A., bud-variation in the vine, 1.
375; in the currant, i. 376 ; in Mirabilis
jalapa, i. 382; in Oytisus adam, 1.
388; on reversion in the foliage of
trees, i. 882; spontaneous production
of Cytisus purpureo-elongatus, i. 390 ;
reversion of flowers by stripes and

nmenontaine

BRAZIL.

INDEX.

BUD-VARIATION. 489

blotches, ii. 87; excess of nourishment
a source of variability, ii. 257,

Brazit, cattle of, i. 88.

BreAD-FRUIT, varieties of, ii. 256; sterility
and variability of, ii. 262.

Bres, W. T., bud-variation in Geranium
pratense and Centaurea cyanus, i. 379 ;
by tubers in the dahlia, i. 385; on the
deafness of white cats with blue eyes,
ii. 329.

Breepine, high, dependent on inheri-
tance, ii. 8-4,

Breeps, domestic, persistency of, ii. 246,
428-429; artificial and natural, ii.
413-414; extinction of, ii. 425; of
domestic cats, i. 45-47; of pigs pro-
duced by crossing, i. 78; of cattle, i,
86-87, 91-93 ; of goats, i. 101.

Breum, on Columba amalizx, i. 183.

Brent, B. P., number of mamme in rab-
bits, i. 106; habits of the tumbler pi-
geon, i. 151; Laugher pigeon, i. 155;
colouring of the kite tumbler, i. 160;
crossing of the pigeon with Columba
enas, 1.193; mongrels of the trumpeter
pigeon, ii. 66; close interbreeding of
pigeons, ii. 126; opinion on Aldro-
vandi’s fowls, i. 247; on stripes in
chickens, i, 249-250; on the combs of
fowls, i. 253; double-spurred Dorking
fowls, i. 255 ; effect of crossing on colour
of plumage in fowls, i. 258 ; incubatory
instinct of mongrels between non-sitting
varieties of fowls, ii. 44; origin of the
domestic duck, i. 277; fertility of the
hook-billed duck, dbid.; occurrence of
the plumage of the wild duck in do-
mestic breeds, i. 280; voice of ducks,
i. 281; occurrence of a short upper
mandible in crosses of hook-billed and
common ducks, i, 281; reversion in
ducks produced by crossing, ii. 40; va-
riation of the canary-bird, i. 295;
fashion in the canary, ii. 240; hybrids
of canary and finches, ii. 45.

Bricke.t, on raising nectarines from
seed, i, 8340; on the horses of North
Carolina, ii. 300.

Briners, Mr., on the dogs of Tierra del
Fuego, i. 39; on the selection of dogs
by the Fuegians, ii. 207,

Bripeman, W. K., reproduction of ab-
normal ferns, i. 383, ii. 379.

Buices, J. J., regeneration of portions of
the fins of fishes, ii. 15,

Broca, P., on the intercrossing of dogs,
1, 31-32 ; on hybrids of hare and rabbit,
i. 105; on the rumpless fowl, i. 259;
on the character of half-castes, ii.
47 ; degree of fertility of mongrels, ii,
100; sterility of descendants of wild
animals bred in captivity, ii. 160,

Broccolt, i. 323 ; rudimentary flowers in,
ii. 316; tenderness of, ii, 310.

BromEHEAD, W., doubling of the Cantcr-
bury bell by selection, ii. 200,

BromFie.p, Dr., sterility of the ivy and
Acorus calamus, ii. 170.

Bromus secalinus, i. 314.

Bronn, H. G., bud-variation in Anthemis,
i. 379; effects of cross-breeding on the
female, i. 404; on heredity in a one-
horned cow, ii. 12, 13; propagation of a
pendulous peach by seed, ii. 18 ; absorp-
tion of the minority in crossed races, ii.
88; on the crossing of horses, ii. 92;
fertility of tame rabbits and sheep, ii.
112; changes of plumage in captivity,
il. 158; on the dahlia, ii. 261.

Bronze period, dog of, i. 18,

Brown, G., variations in the dentition of
the horse, i. 50.

Brown-Séquarp, Dr., inheritance of arti-
ficially-produced epilepsy in the guinea-
pig, il. 24.

Brunswigia, ii. 139.

BrvssExs Sprouts, i. 328, ii. 429.

Bubo maximus, ii. 154.

Bucxianp, F., on oysters, ii. 280; num-
ber of eges in a codfish, ii. 379.

Buckix, Mr., doubts as to the importance
of inheritance, ii. 3. :

Bucxtey, Miss, carrier-pigeons roosting
in trees, i. 181.

Buckman, Prof. cultivation of Avena
jatua, i. 813; cultivation of the wild
parsnip, i, 326, ii. 201, 277; reversion
in the parsnip, ii. 31.

BuckwuHEat, injurious to white pigs, when
in flower, ii. 337.

Bop and seed, close analogy of, i. 411.

BupD-REVERSION, ii. 37.

Buns, adventitious, ii. 384.

Bup-variation, i. 373-411, ii. 254, 287-
288, 291; contrasted with seminal re-
production, i. 373; peculiar to plants, i.
374 ; in the peach, i. 340, 374; in plums,
i. 375; in the cherry, ¢bid.; in grapes,
ibid. ; in the gooseberry, currant, pear,
and apple, i. 376; in the banana, ca-
mellia, hawthorn, Azalea indica, and
Cistus tricuspis, i. 377 ; in the hollyhock
and pelargonium, i. 378; in Geranium
pratenseand the chrysanthemum, 1, 379 ;
in roses, i. 367, 379-381; in sweet wil-
liams, carnations, pinks, stocks, and
snapdragons, i. 381; in wall-flowers, cy-
clamen, Cinothera biennis, Gladiolus
colvillii, fuchsias, and Mirabilis jalapa,
i. 382; in foliage of various trees, i.
382-384; in cryptogamic plants, i. 383 ;
by suckers in Phlow and barberry, i. 384;
by tubers in the potato, bid. ; in the
dahlia, i. 385; by bulbs in hyacinths,

440 BUFFON.

INDEX. CAPE.

Imatophyllum miniatum, and tulips, i.
385; in Tigridia conchiflora, i. 386; in
Hemerocallis, ibid.; doubtful cases, i.
386-387 ; in Cytisus Adami, i. 387-394 ;
probable in Aisculus rubicunda, i. 392 ;
summary of observations on, 406.

Burron, on crossing the wolf and dog, i.
32; increase of fertility by domestica-
tion, ii. 111 ; improvement of plants by
unconscious selection, ii, 216 ; theory of
reproduction, ii, 375.

Bulimus, ii. 53.

Bux, apparent influence of, on offspring,
ii. 68.

Bvutuace, i. 345.

Bu tupoe, recent modifications of, i. 42.

Buuurrncu, breeding in captivity, ii. 154;
attacking flower-buds, ii. 232.

Buur, Mr., selection of pouter pigeons, ii.
197. ;

“ BUNDTNERSCHWEIN,” i. 67.

Buntine, reed, in captivity, ii. 158.

Burpacu, crossing of domestic and wild
animals, i. 66; aversion of the wild boar
to barley, ii. 303.

Burke, Mr., inheritance in the horse, ii. 10.

Burlingtonia, ti. 135.

BurMau, eats of, i. 47.

Burmese ponies, striped, i. 58, 59.

Burnes, Sir A., on the Karakool sheep, i.
98, ii. 278; varieties of the vine in
Cabool, i. 333; hawks, trained in
Scinde, ii.. 153; pomegranates pro-
ducing seed, ii. 168.

Burton Constable, wild cattle at, i. 84.

** BuRZEL-T'AvBEN,” i. 150.

Bussorau carrier, i. 141.

Buteo vulgaris, copulation of, in captivity,
ii. 154.

Burrerriims, polymorphic, ii. 399-400.

BuzaRrEIncvrs, Girou de, inheritance of
.trieks, ii. 6.

CaBANIS, pears grafted on the quince, ii.
239.

CABBAGE, 1. 323-326; varieties of, i. 323;
unity of character in flowers and seeds
of, i. 323-324; cultivated by ancient
Celts, i. 324; classification of varieties
of, ibid.; ready crossing of, ibid., ii. 90,
91, 98, 130; origin of, i. 325; increased
fertility of, when cultivated, ii. 113;
growth of, in tropical countries, ii. 277.

CasooL, vines of, i. 333.

CapBRaL, on early cultivation in Brazil, i.
811.

Cactvs, growth of cochineal on, in India,
li, 275,

Casar, Bos primigenius wild in Europe
in the time of, i. 81; notice of fowls in
Britain, i. 246; notice of the importa-
tion of horses by the Celts, ii. 203,

Carrre fowls, i. 230.

Carrrzs, different kinds of cattle pos-
sessed by the, i. 88.

“ CAaras,”” a breed of sheep, i. 95.

CaALCEOLARIAS, i. 364; ii. 147: effects of
seasonal conditions on, ii. 274; peloric
flowers in, ii. 346.

ees: a Columbian breed of cattle,
i. 88.

Catver, Mr., on a seedling peach pro-

oes both peaches and nectarines, i.

CaLyx, segments of the, converted into
carpels, li. 392.

er its dislike to crossing water, i.

81.

Camellia, bud-variations in, i. 377; recog-
nition of varieties of, ii, 251; variety in,
hardiness of, ii. 308.

Cameron, D., on the cultivation of Alpine
plants, ii. 163.

CameEronN, Baron, value of English blood
in race-horses, ii. 11.

Campanula medium, ii. 200.

CANARY-BIRD, i. 295; conditions of in-
heritance in, ii. 22; hybrids of, ii. 45;
period of perfect plumage in, ii. 77;
diminished fertility of, ii. 161; standard
of perfection in, ii, 195; analogous
variation in, ii. 349;

Cancer, heredity of, ii. 7, 8, 79.

Canine teeth, development of the, in
mares, li. 318.

Canis alopex, i. 29.

Canis antarcticus, i. 20.

Canis argentatus, ii. 151,

Canis aureus, i. 29.

Canis cancrivorus, domesticated and
crossed in Guiana, i. 23.

Canis cinereo-variegatus, i. 29,

Canis fulvus, i. 29.

Canis Inge, the naked Peruvian dog,
he ae

Canis latrans, resemblance of, to the Hare

Indian dog, i. 22; one of the original
stocks, i. 26.

Canis lupaster, i. 25.

Canis lupus, var. occidentalis, resemblance
of, to North American dogs, i. 21;
crossed with dogs, i. 22; one of the
original stocks, i. 26.

Canis mesomelas, i, 25, 29.

Canis primexvus, tamed by Mr. Hodgson,
13526:

Canis sabbar, i. 25.

Canis simensis, possible original of grey-
hounds, i. 33.

Canis thaleb, i. 29.

Canis variegatus, i. 29. :

CANTERBURY Bell, doubled by selection,
li. 200.

Care of Good Hope, different kinds of

CAPERCAILZIE,

INDEX.

CATTLE, 441

eattle at the, i. 88; no useful plants
derived from the, i. 310. se i

CAPERCAILZIE, breeding in captivity, ii.
156.

Capra xgagrus and OC, Falconeri, pro-
bable parents of domestic goat, i. 101,

Capsicum, i. 371. :

CARDAN, on a variety of the walnut, i,

.356; on grafted walnuts, ii. 259-260.

Carpoon, li. 34.

Carex rigida, local sterility of the, ii.
170,

Carer, early selection of sheep, ii. 204.

CaruisLe, Sir A., inheritance of pecu-

_liarities, ii. 6,8; of polydactylism, ii. 13.

“CarME ” pigeon, i. 156. .

CARNATION, bud-variation in, i. 881; va-
riability of, i. 370; striped, produced

.by crossing red and white, i. 393;
ettect of conditions of life on the, ii.
273.

Carnivora, general fertility of, in cap-
tivity, ii. 150.

Caro.ineE Archipelago, cats of, i. 47.

Carp, ii. 236.

Carpets, variation of, in cultivated cu-
curbitacee, i. 359.

Carpenter, W. B., regeneration of bone,
ii. 294; production of double monsters,
ii. 8340; number of eggs in an Ascaris,
li. 379.

Carpinus betulus, i. 362.

Carpophaga littoralis and luctuosa, i. 182.

Carrier pigeon, i, 139-142; English, i.
139-141; figured, 1.140; skull figured,
i. 163; history of the, i. 211; Persian,
i. 141; Bussorah, ibid.; Bagadotten,

skull figured, i. 163; lower jaw figured,
L 2655:
Canki&re, cultivation of the wild carrot,
1. 826; intermediate form between the
almond and the peach, i. 338; glands
of peach-leaves, i, 343; bud-variation
in the vine, i. 375; grafts of Aria vestita
upon thorns, i. 387; variability of
hybrids of Erythrina, ii. 265.

Carrot, wild, effects of cultivation on the,
i. 326; reversion in the, ii. 31; run
wild, ii. 33; increased fertility of cul-

. tivated, ii. 113; experiments on the, ii.
277; acclimatisation of the, in India,
il. 311.

eae abortion of the pappus in, ii.

6.

Cartier, cultivation of native plants in
Canada, i. 312.

CARYOPHYLLACEA, frequency of conta-
bescence in the, ii. 165.

Caspary, bud-variation in the mMoss-rose,
i. 380; on the ovules and pollen of
Cytisus, i. 388-389 ; crossing of Cytisus
purpureus and C, laburnum, i. 389°; tri-

facial orange, i. 391; differently-co-
loured flowers in the wild Viola lutea,
i, 408; sterility of the horse-radish, ii.
170.

CasTELNAU, on Brazilian cattle, i. 88.

CASTRATION, assumption of female cha-
racters caused by, ii. 51-52,

Casuarius bennettii, ii. 156.

Cat, domestic, i. 43-48 ; early domestica-
tion and probable origin of the, i. 43-
44; intercrossing of with wild species,
i, 44-45; variations of, i. 45-48: feral,
i. 47, ii. 33; anomalous, i. 48; poly-
dactylism in, ii. 14; black, indications
of stripes in young, ii. 55; tortoiseshell,
11.73; effects of crossing in, ii. 86; fer-
tility of, ii. 111; difficulty of selection
in, i. 234, 236; length of intestines in,
ii. 302; white with blue eyes, deafness
of, ii. 8329; with tufted ears, ii, 350,

Cataract, hereditary, ii. 9, 79.

CATERPILLARS, effect of changed food on,
ii, 280.

CaT1in, G., colour of feral horses in North
America, i. 61.

Carrir, European, their probable origin
from three original species, i. 79-82;
humped, or Zebus, i. 79-80; inter-
crossing of, i. 83, 91-93; wild, of Chil-
lingham, Hamilton, Chartley, Burton
Constable, and Gisburne, i. 84, ii. 119;
colour of feral, i. 84-85, ii. 102; British
breeds of, i. 86-87; South African
breeds of, 1, 88; South American breeds
of, i. 89, ii, 205; Niata, i. 89-91, ii.
205, 208, 332; effects of food and
climate on, i. 91-92; effects of selection

on, i, 92-93; Dutch-buttocked, ii. 8;
hornless, production of horns in, ii. 29-
30, 39; reversion in, when crossed, ii.
41; wildness of hybrid, ii. 45; short-
horned, prepotency of, ii. 65; wild,
influence of crossing and segregation
on, ii. 86; crosses of, ii, 96, 104, 118;
of Falkland islands, ii. 102; mutual
fertility of all varieties of, ii. 110;
effects of interbreeding on, ii. 117-
119; effects of careful selection on, ii.
194, 199; naked, of Columbia, ii.
205; crossed with wild banteng in
Java, ii. 206; with reversed. hair in
Banda Oriental, ii. 205; selection of
trifling characters in, ii. 209; fashion
in, ii. 210; similarity of best races of,
li. 241; unconscious selection in, ii.
214; effects of natural selection on
anomalous breeds of, ii. 226-227; light-
coloured, attacked by flies, ii. 229, 336 ;
Jersey, rapid improvement of, ii. 234;
effects of disuse of parts in, ii. 299;
rudimentary horns in, ii. 315; sup-
posed influence of humidity on the hair

EE ee

449

CAULIFLOWER.

of, ii. 326; white spots of, liable to
disease, ii. 337; supposed analogous
variation in, ii. 349; displacement of
long-horned by short-horned, ii. 426,

CAULIFLOWER, i, 323; free-seeding of, in
India, ii. 310; rudimentary flowers in,
ii. 816.

CAVALIER pigeon, ii. 97.

Cavia aperea, ii, 152.

Cay (Cebus azarx), sterility of, in con-
finement, li. 153.

Cebus azare, ii. 153.

Cecidomyia, larval development of, ii. 283,
360, 367; and Misolampus, i. 5.

Crepanrs of Lebanon and Atlas, i. 364.

CrLery, turnip-rooted, i. 336; run wild,
ii. 33.

CELL-THEORY, ii. 370.

Celosia cristata, 1. 365.

Crxsus, on the selection of seed-corn, i.
318, ii. 203.

Ceuts, early cultivation of the cabbage
by the, i. 8324; selection of cattle and
horses by the, ii. 202-203.

Cenchrus, seeds of a, used as food, i. 309.

Centaurea cyanus, bud-variation in, i.
379.

CEPHALOPODA, spermatophores of, ii. 383.

Cerasus padus, yellow-fruited, ii. 19.

Cercoleptes, sterility of, in captivity, ii.
152.

Cercopithecus, breeding of a species of, in

* captivity, ii. 153.

CEREALS, i. 312-313; of the Neolithic
period in Switzerland, i. 317 ; adapta-
tion of, to soils, ii. 305.

Cereus, ii. 38.

Cereus speciosissimus and phyllanthus, re-
version in hybrids of, i. 392.

Cervus canadensis, ii. 158,

Cervus dama, ii. 120.

Ceracea, correlation of dermal system
and teeth in the, ii. 328.

Cryion, cats of, i. 46; pigeon-fancying
in, i. 206.

Chamexrops humilis, crossed with date
palm, i, 899.

CHaAmIsso, on seeding bread-fruit, ii. 168.

CHANNEL islands, breeds of cattle in, i.
80.

Cuarman, Professor, peach-trees pro-
ducing nectarines, i. 341.

Cuaruis, F., sexual peculiarities in
pigeons, i. 162, ii.'74; effect produced
by first male upon the subsequent pro-
geny of the female, i. 405; sterility of
the union of some pigeons, ii. 162.

Cuaracters, fixity of, ii. 239; latent, ii.
51-56, 399-400; continued divergence
of, ii. 241; antagonistic, ii. 401.

CHARDIN, abundance of pigeons in Persia,
i. 205,

INDEX.

CITRUS.

CHARLEMAGNE, orders as to the selection
of stallions, ii. 203.

Currey, wild cattle of, i. 84.

Cuars, reversion of the upper seeds in
the pods of stocks, ii, 347-348.

Cuatin, on Ranunculus ficaria, ii. 170.

Cuaunpy, Mr., crossed varieties of cab-
bage, ii. 130.

le cr general sterility of, in captivity,
il. 151,

Cheiranthus chetri, i. 382.

CHERRIES, i, 347-348; bud-variation in,
1.875; white Tartarian, ii. 230; variety
of, with curled petals, ii, 232 ; period of
nee of, changed by forcing, ii.

CHEVREUL, on crossing fruit-trees, ii, 129.

CuIcKEns, differences in characters of, i.
249-250; white, liable to gapes, ii,
228, 336.

CuicoR, ii. 275.

CHILE, sheep of, i. 95.

CHILLINGHAM cattle, identical with Bos
primigenius, i, 81; characters of, i,
83-84.

Cui1og, half-castes of, ii. 46.

Curna, cats of, with drooping ears, i. 47;
horses of, i. 53; striped ponies of, i.
59; asses of, i. 62; notice of rabbits in,
by Confucius, i. 103; breeds of pigeons
reared in, i. 206; breeds of fowls of, in

fifteenth century, i. 232, 247; goose of,
i. 237,

CHINCHILLA, fertility of, in captivity, ii.
152.

CutneEse, selection practised by the, ii.
204-205; preference of the, for horn-
less rams, ii. 209; recognition of the
value of native breeds by the, ii. 313.

CHINESE, or Himalayan rabbit, i. 108.

“‘ Curvos,” a breed of cattle in Paraguay,
i. 89.

CHOUX-RAVES, 1. 323.

Curist, H., on the plants of the Swiss
Lake-dwellings, i. 809, 318; interme-
diate forms between Pinus sylvestris
and montana, 1. 363.

CHRYSANTHEMUM, 1. 379.

Chrysotis festiva, ii, 280. 3

CINERARIA, effects of selection on the, i.
200.

CrroasstA, horses of, ii. 102.

CIRCUMCISION, ii. 23.

CrrrIPEDEs, metagenesis in, li. 366. ;

Cistus, intercrossing and hybrids of, i.
336, 389, ii. 140. ;

Cistus tricuspis, bud-variation in, i. 377.

Crrrons, i. 334-335. Sg

“ Citrus aurantium fructu variabili,” 16
336.

Citrus decumana, i. 335.

Citrus lemonum, i. 336.

CITRUS.

. INDEX. °

443

COLUMBINE,

Citrus medica, i. 335-336.

Cert palate, inheritance of, ii. 24.

CLEMENTE, on wild vines in Spain, i.
332.

CLERMONT-TONNERRE, on the St. Valery
apple, i. 401.

CiarHamM, A., bud-variation in the haw-
thorn, i. 377.

* CLAQUANT,” i. 138.

“* CLAQUERS”’ (pigeons), i. 156.

Ciark, G., on the wild dogs of Juan de
Nova, i. 27; on striped Burmese and
Javanese ponies, i, 59; breeds of goats
imported into the Mauritius, i. 101;
variations in the mamme of goats, i.
102; bilobed scrotum of Muscat goat,
ibid.

Ciark, H. J., on fission and gemmation,
ii. 859.

CuarkE, R. T., intercrossing of straw-
berries, i. 852.

Cuarke, T., hybridisation of stocks, i.
399, ii, 93.

Ciarkson, Mr., prize-cultivation of the
gooseberry, i. 855.

CLASSIFICATION, explained by the theory
of natural selection, i. 11.

Cimate, effect of, upon breeds of dogs,
i. 87; on horses, i. 52, 53; on cattle, i,
91, 92; onthe fleece of sheep, i. 98,99;
on seeds of wheat,i. 316; on cultivated
cabbages, i, 325; adaptation of maize
to, i, 322.

CLIMATE and pasture, adaptation of breeds
of sheep to, i. 96-97,

CuImATE and soil, effects of, upon straw-
berries, i. 353.

Ciinz, Mr., on the skull in horned and
hornless rams, ii. 333.

Cios, on sterility in Ranunculus Jjicaria,
ii. 170.

Crorzscu, hybrids of various trees, ii. 130.

Cover, pelorism in, ii. 340.

i he Mr., on interbreeding pigs, ii.
122.

Coccus of apple trees, ii. 281.

Cocutn fowls, i. 227, 250, 252, 260-261 ;
occipital foramen of, figured, i. 261;
section of skull of, figured, i. 263 ; cer-
vical vertebra of, figured, i. 267.

CocHINEAL, persistence of, ii. 236; pre-
soroMee of, for a particular cactus, ii,
279.

Cochlearia armoracia, ii. 170.

Cock, game, natural selection in, ii, 295 ;
spur of, grafted on the comb, ii, 296;
spur of, inserted into the eye of an OX,
il. 369; effect of castration upon the,
ii. 51-52,

Cock’s-comp, varieties of the, i. 365.

Cocoons, of silkworms, variations in, i.
302-303,

Coprisu, bulldog, i. 89; number of eges
in the, ii. 379,

Ceelogenys paca, ii. 152,

CoLIn, prepotency of the ass over the
horse, ii. 67-68; on cross- breeding, ii.
97; on change of diet, ii. 304.

CoLuinson, Peter, peach-tree producing a
nectarine, i. 340, ,

CoLORATION, in pigeons, an ‘evidence of
unity of descent, i. 195-197.

Cotovr, correlation of, in dogs, i. 28-29:
persistence of, in horses, i. 50; in-,
heritance and diversity of, in horses, i.
D9; variations of, in the ass, 1. 62-63;
of wild or feral cattle, i. 85; transmis-
sion of, in rabbits, i. 107; peculiarities
of, in Himalayan rabbits, i. 111; in-
fluence of, ii. 227-230; correlation of,
in head and limbs, ii. 824; correlated
with constitutional peculiarities, ii. 835-
338,

Cotovr and odour, correlation of, ii. 325.

CoLOUR-BLINDNESS, hereditary, ii. 9; more
common in men than in women, ii. 72-
73; associated with inability to dis-
tinguish musical scunds, ii. 328.

Cotours, sometimes not blended by cross-
ing, li. 92.

Columba affinis, Blyth, a variety of C.
livia, i. 183.

Columba amalix, Brehm, a variety of C.
livia, i. 183.

Columba guinea, i. 182.

- Columba gymnocyclus, Gray, a form of C.

livia, i. 184.

Columba gymnophthalmos, hybrids of, with
C. enas, i. 193; with C. maculosa, i.
194.

Columba intermedia, Strickland, a variety
of C. livia, i. 184.

Columba leucocephala, ii. 155.

Columba leuconota, i. 182, 195.

Columba littoralis, i. 182.

Columba livia, ii. 29, 40; the parent of
domestic breeds of pigeons, i. 183; mea-
surements of, i. 184; figured, i. 135;
skull figured, i. 163 ; lower jaw figured,
i. 164, 168; scapula figured, i. 167.

Columba luctuosa, i. 182.

Columba migratoria and lewcocephala, di-
minished fertility of, in captivity, i.
155.

Columba cenas, i, 183; crossed with com-
mon pigeon and OC. gymnophthalmos, i.
193.

Columba palumbus, i. 193, ii. 850.

Columba rupestris, i. 182, 184, 195.

Columba Schimperi, i. 184.

Columba torquatria, ii. 350.

Columba turricola, i. 184.

CoLumsta, cattle of, i. 88.

CoLumBinE, double, i. 365, ii, 330.

OE SIL I

f

444

COLUMBUS.

Cotumsvs, on West Indian dogs, i. 23,
CoLuMELLA, on Italian shepherd’s dogs, i.
23; on domestic fowls, i. 231, 247, ii.
202, 429; on the keeping of ducks, i.
277; on the selection of seed-corn, i.
318; on the benefits of change of soil
to plants, ii. 146; on the value of na-
tive breeds, ii. 313.
Couza, i. 825.
Comp, in fowls, variations of, i. 258-254;
sometimes rudimentary, ii. 315.
COMPENSATION, law of, i. 274.
CoMPENSATION of growth, ii. 842-344.
CoMPLEXION, connexion of, with constitu-
tion, 11,7835,
Composirm, double flowers of, i. 865, ii.
167, 316.
ConcEePTIoN, earlier in Alderney and
Zetland cows than in other breeds,
i. 87.
Conprtions of life, changed, effect of, ii.
418-419; on horses, i. 52; upon va-
riation in pigeons, i. 212-213; upon
wheat, i. 315-316; upon trees, i. 361;
in producing bud-variation, i. 408; ad-
vantages of, ii. 145-148, 176-177; ste-
rility caused by, ii. 148-165; conducive
to variability, ii. 255-261, 394; accu-
‘mulative action of, ii. 261-263; direct
action of, ii. 271-292,
Connor, breeding in captivity, ii. 154.
CONFINEMENT, effect of, upon the cock,
ii, 52. teat
_ConFuctus, on the breeding of rabbits in
China, i. 103.
Conoty, Mr., on Angora goats, ii. 326.
OonstiruTionaL differences in sheep, i.
96-97; in varieties of apples, i. 349-
390; in pelargoniums, i. 364; in
dahlias, i. 370.
CoNsTITUTIONAL peculiarities in straw-
berries, i. 353; in roses, i. 367,
Consumprion, hereditary, ii. 8; period of
appearance of, ii. 77; correlated with
complexion, ii. 335.
CoNTABESCENCE, ii. 165-166.
Convolvulus batatas, ii. 169, 309.
Convolvulus tricolor, bud-variation in, i.
408.
Coorrr, Mr., improvement of vegetables
- by selection, ii. 204.
Coorrr, White, hereditary peculiarities
of vision, ii. 9; association of affections
of the eyes with those of other systems,
li. 328.
Corats, bud-variation in, i. 374; non-
diffusion of cell-gemmules in, ii. 379.
Corsif. See Boitard,
Cornea, opacity of, inherited, ii. 9.
Cornus mascula, yellow-fruited, ii. 19.

CoRRELATION, ii, 319; of neighbouring |

parts, ii. 320; of change in the whole

INDEX.

CRAWFURD.

body and in some of its parts, ii. 321;
of homologous parts, ii. 8322-331; inex-
plicable, ii. 331-333; commingling of,
with the effects of other agencies, ii.
333-335.

CorreLarton of skull and limbs in swine,
1. 73; of tusks and bristles in swine, i.
76; of multiplicity of horns and coarse-
ness of wool in sheep, i. 95; of beak
and feet in pigeons, i. 172-173: between
nestling down and colour of plumage
in pigeons, i. 194; of changes in silk-
worms, i. 304; in plants, ii. 219; in
maize, i. 823; in pigeons, i. 167-171,
218; in fowls, i. 274-275.

CorresPonDIne periods, inheritance at, ii.
75-80.

Corrientes, dwarf cattle of, i. 89.

CorrincHam, Mr., influence of selection
on pigs, ii. 198.

Corsica, ponies of, i. 52.

“ CortBEcK” (pigeon) of Aldrovandi, i.
209.

Corvus corone and C. cornix, hybrids of,
ii. 94,

Corydalis, flower of, ii. 304.

Corydalis cava, ii. 182-133.

Corydalis solida, sterile when peloric, ii.
167.

Corydalis tuberosa, peloric by reversion,
ll. 58-59.

Corylus avellana, i. 357.

Costa, A., on shells transferred from
England to the Mediterranean, ii. 280.

“‘ CouvE TRONCHUDA,” i. 323.

Cow, inheritance of loss of one horn in
the, ii. 12, 23; amount of milk fur-
nished by the, ii. 300; development of
six mamme in, ii. 317.

Cowstip, ii. 21, 182.

Cracip4, sterility of the, in captivity, ii.
156.

Cranus, fertility of, in captivity, ii. 156.

Crategus oxyacantha, i. 363, li. 18, 232,
258, 377.

Cratzgus monogyna, i. 864.

Crategus sibirica, i. 364.

CRAWFURD, J., Malasian cats, i.47; horses
of the Malay Archipelago, i. 49; horses
of Japan, i, 53; occurrence of stripes
in young wild pigs of Malacca, i. 76;
on a Burmese hairy family with de-
ficient teeth, ii. 77, 327; Japanese origin
of the bantam, i. 230; game fowls of
the Philippine islands, i, 282; hybrids
of Gallus varius and domestic fowl, 1.

234; domestication of Gallus bankiva,
1. 236; feral fowls in the Pelew islands,
i. 288; history of the fowl, i, 246; his-
tory of the domestie duck, i. 277; do-
mestication of the goose, i. 287; culti-
vated plants of New Zealand, i. 312;

CREEPERS,

INDEX,

DAMARAS, 4.45)

breeding of tame elephants in Ava, ii.
150; sterility of Goura coronata in con-
finement, ii. 155; geese of the Philip-
pine islands, ii. 162.

CREEPERS, a breed of fowls, i. 230.

CresTED fowl, i. 227; figured, i. 229.

“ CrEve-cmur,” a French sub-breed of
fowls, i. 229.

Crisp, Dr., on the brains of the hare and
rabbit, i. 126.

Crocker, C. W., singular form of Begonia
frigida, i. 365-366, ii. 166; sterility
in Ranunculus ficaria, ii. 170.

Crocus, ii. 165.

CROSS-BREEDING, permanent effect of, on
the female, i. 404.

CrossinG, ii. 85-144, 173-192; a cause of

uniformity, ii. 85-90, 173; occurs in all

organised beings, ii, 90-92; some cha-

racters not blended by, ii. 92-95, 173;

modifications and new races produced

by, ii. 95-99 ; causes which check, ii. 100-

109; ‘domestication and cultivation

favourable to, ii. 109-113, 189; beneficial

effects of, ii. 114-131, 174-176; necessary

in some plants, ii. 131-140, 175-176, 423;

summary of subject of, ii. 140-144; of

dogs with wolves in North America,

i. 21-22; with Canis cancrivorus in

Guiana, i. 23; of dog with wolf, de-

scribed by Pliny and others, i. 24; cha-

racters furnished by, brought out by

reversion in the progeny, ii, 34-36; a

direct cause of reversion, ii. 39-47, 48;

a cause of variability, ii. 264-267.

Crustacea, macrourous, differences in the
development of the, ii. 368.

Crustacean with an antenna-like de-
velopment of the eye-peduncle, ii.
Be eae

Cryprocamic plants, bud-yariation in, i.

Cusa, wild dogs of, i. 27,

“ Cuckoo,” sub-breeds of fowls, i. 244.

Cucumprr, variation in number of carpels
of, i. 359; supposed crossing of va-
rieties of the, i. 400.

Cucumis momordica, i. 360,

Cucumis sativa, i. 359,

Cucurbita, dwarf, correlation of leaves in,
ii. 330.

Cucurbita maxima, i. 857, 359.

Cucurbita moschata, i. 357, 359.

Cucurbita pepo, i. 357, ii. 108; varieties
of, i. 858; relation in size and number
of fruit of, ii, 343,

CUCURBITACER, i. 357-360; supposed
crossing of, i. 399; Naudin’s observa-
tions on hybrids of, ii. 172; acclimati-
sation of, ii. 313.

“ CULBUTANTS ” (pigeons), i. 150.

CuLtivation of plants, origin of, among

savages, 1. 309-310; fertility increased
by, ii. 111-113,

oo on hereditary night-blindness,
it, 9:

Currants, of Tierra del Fuego, i. 309;
bud-variation in, i. 876,

hte Mr., bud-variation in the rose, i.

Cuvier, on the gestation of the wolf, i.
29; the odour of the jackal, an obstacle
to domestication, i. 30; differences of
the skull in dogs, i. 834; external cha-
racters of dogs, i. 35; elongation of the
intestines in domestic pigs, i. 73, ii.
303; fertility of the hook-billed duck,
i. 277 ; number of digits, ii. 13; hybrid
of ass and zebra, ii. 42; breeding of
animals in the Jardin des Plantes, ii.
149; sterility of predaceous birds in
captivity, ii. 154; facility of hybridisa-
tion in confinement, ii. 160.

Cyanosis, affection of fingers in, ii, 332.

CycuameEn, bud-variation in, i, 882.

Cynara cardunculus, ii. 34.

Cynips fecundatriz, ii. 283.

Cynocephalus hamadryas, ii. 153,

Cyprinus auratus, i, 296-297,

Cyrtanthus, ii, 139.

Cyrtopodium, ii. 134.

Cytisus Adami, ii. 364; its bud-variation,
i, 387-389, 406, ii. 37; seedlings from,
i, 3888; different views of its origin, i.
389-390; experiments in crossing C.
purpureus and laburnum to produce, i.
‘389; its production by M, Adam, i,
390 ; discussion of origin of, i. 396,

Cytisus alpino-laburnum, ovules and pol-
len of, i. 389; origin of, i. 390,

Cytisus alpinus, i. 388.

Cytisus laburnum, i. 387, 389, 390, 396.

Cytisus purpureo-elongatus, ovules and
pollen of, 1. 389; production of, i. 390.

Cytisus purpureus, i. 387, 388, 389, 390,
396,

Dautsom, effects of food on hymenoptera,
ii. 281.

Dau, i. 369-370, ii. 147; bud-varia-
tion by tubers in the, i. 385; improve-
ment of, by selection, ii. 216; steps in
cultivation of, ii. 261; effect of condi-
tions of life on, ii. 273; correlation of
form and colour in, ii. 331,

Daisy, hen and chicken, i. 365; Swan
River, ii. 261.

DaA.pret, varieties of wheat, i. 314.

Da rBert, changes in the odours of plants,
li, 274. é :

Datty, Dr., on consanguineous marriages,
ii. 122.

Daxronism, hereditary, ii. 9,

Damaras, cattle of, i. 88, ii, 207-208,

‘446

DAMSON.

INDEX.

DEVELOPMENT.

Damsov, i. 347.

Danvo1o, Count, on silkworms, i. 301.

DanIzLL, fertility of English dogs in
Sierra Leone, ii. 161.

DanisH Middens, remains of dogs in, i. 18.

ee in horses, asses, and hybrids,
eS

Danreste, C., on the skull of the Polish
fowl, i. 262; on the production of mon-
strous chickens, ii. 289; co-existence of

anomalies, ii. 331; production of double
monsters, ii. 340.

Darvitt, Mr., heredity of good qualities
in horses, ii. 11.

Darwin, C., on Lepus magellanicus, i. 112;
on the wild potato, i. 330; dimorphism
in the polyanthus and primrose, ii. 21.

Darwin, Dr., improvement of vegetables
by selection, ii. 204.

Darwin, Sir F., wildness of crossed pigs,
li. 45.

D’Asso, monogynous condition of the
hawthorn in Spain, i. 364.

Dasyprocta agutt, ii. 152.

Date-palm, varieties of the, ii. 256; effect
of pollen of, upon the fruit of Chame-
rops, i. 299.

Datura, ii. 38; variability in, ii. 266.

Datura levis and stramonium, reversion
in hybrids of, i. 392.

Datura stramonium, ii. 67.

DAUBENTON, variations in the number of
mamme in dogs, i. 35; proportions of
intestines in wild and domestic cats, i.
48, ii. 302.

Davptn, on white rabbits, ii. 250.

“Davy, Dr., on sheep in the West Indies, i.98.
Dawkins and Sandford, early domestica-
tion of Bos longifrons in Britain, i. 81.

DerEAF-mUTES, non-heredity of, ii. 22.

Deraryess, inheritance of, ii. 78.

Desy, wild hybrids of common and musk
ducks, ii. 46.

Der Canpotie, Alph., number and origin
of cultivated plants, i. 306-307, 371;
regions which have furnished no useful
plants, i. 310-; wild wheat, i, 312-318 ;
wild rye and oats, i, 313; antiquity of
varieties of wheat, i. 316; apparent in-
efficacy of selection in wheat, i. 318;
origin and cultivation of maize, 1. 320, ii.
307; colours of seeds of maize, i. 321 ;
varieties and origin of the cabbage, i.
324-325; origin of the garden-pea, i.
326; on the vine, i. 332, ii. 308 ; culti-
vated species of the orange group, i.
835; probable Chinese origin of the
peach, i. 337; on the peach and necta-
rine, i. 840, 342; varieties of the peach,
i. 342; origin of the apricot, 1. 344;
origin and varieties of the plum, 1. 345 ;
origin of the cherry, i. 3847; varieties

of the gooseberry, i. 854; selection
practised with forest-trees, i. 361 ; wild
fastigate oak, i. 361; dark-leaved va-
rieties of trees, i. 362; conversion of
stamens into pistils in the poppy, i.
365 ; variegated foliage, i. 366 ; heredity
of white hyacinths, i. 371, ii. 20; changes
in oaks dependent on age, i. 8387; inhe-
ritance of anomalous characters, ii. 19 ;
variation of plants in their native coun-
tries, ii, 256 ; deciduous bushes becom-
ing evergreen in hot climates, ii. 305 ;
antiquity of races of plants, ii. 429.

Der CANDOLLE, P., non-variability of mono-
typic genera, li. 266; relative develop-
ment of root and seed in Raphanus
sativus, li. 843.

Decaisne, on the cultivation of the wild
carrot, i. 326; varieties of the pear, i.
350; inter-crossing of strawberries, i.
351; fruit of the apple, i.401; sterility
of Lysimachia nummularia, ii. 170;
tender variety of the peach, ii. 308.

Derr, assumption of horns by female, ii.
51; imperfect development of horns in
a, on a voyage, li. 158,

Deer, fallow, ii. 103.

Drrrnounn, Scotch, difference in size of
the sexes of, ii. 73 ; deterioration of, ii.
121,

DEGENERATION of high-bred races, under
neglect, ii. 239. .
Der Jonaue, J., on strawberries, i. 352, ii.
243; soft-barked pears, ii. 231; on ac-
cumulative variation, ii, 262 ; resistance

of blossoms to frost, ii. 306.

Detamer, E. §., on rabbits, i. 107, 112.

Delphinium ajacis, ii. 21.

Delphiniwm consolida, ii, 20-21.

Dendrocygna viduata, ii. 157.

DENTITION, variations of, in the horse, i.
50.

Deropar, i. 364.

DesmAkeEstT, distribution of white on dogs,
i. 29; cat from the Cape of Good Hope,
i. 47; cats of Madagascar, i. 47; oc-
currence of striped young in Turkish
pigs, i. 76; French breeds of cattle, i.
80; horns of goats, i, 102 ; on hornless
goats, ii. 315. :

Desor, E., on the Anglo-Saxon race in
America, ti. 276. ;

Desrortes, number of varieties of roses, 1.
367.

Devay, Dr., singular case of albinism, il.
17; on the marriage of cousins, ii. 122 ;
on the effects of close interbreeding, 11.
148, 263. i

DEVELOPMENT and metamorphosis, 1. 388-
389.

Drvetorment, arrests of, ii, 315-318.

DEVELOPMENT, embryonic, ii. 366-368.

duals

D’ HERVEY. INDEX. DOGS. 447

D'Hervey-Saint-Denys, L., on the ya-mi,
or imperial rice of the Chinese, ii. 205.

Duots, fertility of the, in captivity, ii,
151.

DIABETES, occurrence of, in three brothers,
ii. 17.

Dianthus, contabescent plants of, ii. 165-
166 ; hybrid varieties of, ii. 267.

Dianthus armeria and deltoides, hybrids of,
ii. 98.

Dianthus barbatus, i. 881.

Dianthus caryophyllus, i. 381.

Dianthus japonicus, contabescence of
female organs in, ii. 166.

Dicnocamovts plants, ii. 90.

Dickson, Mr., on “ running ” in carnations,
i. 881; on the colours of tulips, i. 386.

Dicotyles torquatus and labiatus, ii. 150.

DIEFFENBACH, dog of New Zealand, i. 26;
feral cats in New Zealand, i. 47; poly-
dactylism in Polynesia, ii. 14.

Dielytra, ii. 59.

Dirt, change of, ii. 303-304.

Digitalis, properties of, affected by cul-
ture, ii. 274; poison of, ii. 380.

Dicrrs, supernumerary, ii. 57; analogy of,
with embryonic conditions, ii, 16 ;
fusion of, ii. 341.

Diorputc plants, ii. 166; conditions of
reproduction in, ii. 181-184,

Dimorruism, reciprocal, ii. 90.

D1nGo, i. 25 ; variation of, in colour, i. 28;

zi half-bred, attempting to burrow, i. 28;
attraction of foxes by a female, i. 31;
variations of, in confinement, ii. 263.

Diacrousness of strawberries, i. 353.

Disrases, inheritance of, ii. 7-8; family
uniformity of, ii.57; inherited at corré-
sponding periods of life, ii. 77-80 ; pe-
culiar to localities and climates, ii-276 ;
obscure correlations in, ii, 331-332;
affecting certain parts of the body, ii.
380; occurring in alternate generations,
ii. 401.

Disremprr, fatal to white terriers, ii, 227,

Disusx and use of parts, effects of, ii, 295-
303, 352-353, 418-419: in the skeleton
of rabbits, i. 124-128 ; in pigeons, i. 171-
177; in fowls, i. 270-274; in ducks, i.
284-286 ; in the silk-moth. i, 300-304, '

DivercENor, influence of, in producing
breeds of pigeons, i. 220.

Drxon, E. §., on the musk duck, i, 182 ;
on feral ducks, i. 190; on feral pigeons
in Norfolk Island, i. 190; crossing
of pigeons, i. 192; origin of domes.
tic fowls, i, 230; crossing ‘of Gallus
Sonneratii and common fowl, i. 234;
occurrence of white in the young
chicks of black fowls, i. 244; Paduan
fowl of Aldrovandi, i. 247; pecu-
liarities of the eggs of fowls, i, 248 ;

chickens, i. 249-250; late development
of the tail in Cochin cocks, i. 250; comb
of lark-crested fowls, i. 256; develop-
ment of webs in Polish fowls, i. 259;
on the voice of fowls, i, 259 ; origin of
the duck, i. 277; ducks kept by the
Romans, i. 278; domestication of the
goose, i. 287; gander frequently white,
1. 288; breeds of turkeys, i. 293; incu-
batory instinct of mongrels of non-
sitting races of fowls, ii. 44; aversion
of the dove-cot pigeon to pair with
fancy birds, ii. 103; fertility of the
goose, ii. 112; general sterility of the
guans in captivity, ii. 156; fertility of
geese in captivity, ii. 157; white pea-
towl, ii. 332.

Dosen, H., inheritance of anomalies of
the extremities, ii. 14; non-reversion to
a malformation, ii. 36,

Dosriznorrer, abhorrence of incest by the
Abipones, ii. 123.

Does, origin of, i. 15; ancient breeds of,
i. 17, ii. 429; of neolithic, bronze and
iron periods in Europe, i. 18-19, ii.
427; resemblance of to various species
of canide, i. 21; of North America
compared with wolves, i. 21-22; of the
West Indies, South America, and
Mexico, i. 23, 31; of Guiana, i. 23; naked.
dogs of Paraguay and Peru, ibid. and
31; dumb, on Juan Fernandez, i. 27 ;:
of Juan de Nova, i. 27; of La Plata, i.
27; of Cuba, i. 27; of St. Domingo, i.
28; correlation of colour in, i. 28-29 ;
gestation of, i. 29-30; hairless Turkish,
i. 30, ii. 227; inter-crossing of different
breeds of, i. 31; characters of different
breeds of, discussed, i. 34-37; degene-
ration of European, in warm climates,
i. 36, 38; ii. 278, 305; liability to
certain diseases in different breeds of,
i. 386 and note; causes of differences
of breeds discussed, i. 37-43; catch-
ing fish and crabs in New Guinea
and Tierra del Fuego, i. 39; web-
bing of the feet in, i. 89; influence
of selection in producing different
breeds of, i. 39, 43; retention of original
habits by, i. 182; inheritance of poly-
dactylism in, ii. 14; feral, ii. 33; re-
version in fourth generation of, ii. 34;
of the Pacific Islands, ii. 87, 220, 303;
mongrel, ii. 92-93 ; comparative facility
of crossing different breeds of, ii, 102;
fertility of, ii. 111, 151; inter-breeding
of, ii. 120-121 ; selection of, among the
Greeks, ii, 202, 209; among savages,
ii. 206-207; unconscious selection of,
li. 211-212; valued by the Fuegians,
ii, 215; climatal changes in hair of,
ii, 278; production of drooping ears

448

INDEX.

EATON.

DOMBRAIN.
in, ii. 301; rejection of bones of
game by, ii. 303; inheritance of ru-

diments of limbs in, ii. 315; develop-
ment of fifth toe in, ii. 317 ; hairless, de-
ficiency of teeth in, ii. 326 ; short-faced,
teeth of, ii. 8345; probable analogous
variation in, il. 349; extinction of
breeds of, ii. 425.

Domprain, H. H., on the auricula, ii.
346-347.

DomeEstIcaTIon, essential points in, ii.
405-406 ; favourable to crossing, ii. 109-
110; fertility increased by, ii, 111-113,
174.

DomeEstIcaTED animals, origin of, ii. 160-
161; occasional sterility of, under
changed conditions, ii. 161-162.

Donpers, Dr., hereditary hypermetropia,
ii. 8.

Dorxine fowl, i. 227, 261; furcula of,
figured, i. 268.

Dormovsg, ii. 152.

DovstE flowers, ii. 167-168, 171-172 ; pro-
duced by selection, ii. 200.

Dovs.epAy, H., cultivation of the filbert
pine strawberry, i. 354.

Doveuas, J., crossing of white and black
game-fowls, ii. 92.

Downinc, Mr., wild varieties of the
hickory, i. 310; peaches and nectarines
from seed, i. 339-340; origin of the
Boston nectarine, i. 340; American
varieties of the peach, i. 343; North
American apricot, i. 344; varieties of
the plum, i. 346; origin and varieties
of the cherry, i. 347-348; “twin clus-
ter pippins,”’ i. 349; varieties of the
apple, i. 350; on strawberries, i. 351,
353; fruit of the wild gooseberry, i.
355 ; effects of grafting upon the seed,
ii. 26; diseases of plum and peach
trees, ii. 227-228 ; injury done to stone
fruit in America by the “ weevil,” ii.
231; grafts of the plum and peach, ii.
259; wild varieties of pears, ii. 260;
varieties of fruit-trees suitable to differ-
ent climates, ii. 306.

Draba sylvestris, ii. 163.

Dragon, pigeon, i. 139, 141.

“ DRAWER” (pigeon), i. 156.

Drrnx1n¢, effects of, in different climates,
li. 289,

Dromepary, selection of, ii. 205-206.

Drvcz, Mr., inter-breeding of pigs, ii. 121.

Dv CuHat10, fruit-trees in West Africa, i.
309.

Docnesne on Fragaria vesca, i, 351, 352,
353.

Durovur, Léon, on Cecidomyia and Miso-
campus, i. 5.

Dwck, musk, retention of perching habit
by the, i. 182; feral hybrid of, i. 190.

Duck, penguin, hybrid of, with Egyptian
goose, ii. 68.

Ducx, wild, difficulty of rearing, ii. 233 ;
effects of domestication on, ii. 278.

Ducks, breeds of, i. 276-277; origin of, i.
277; history of,ibid.; wild, easily tamed,
i. 278-279 ; fertility of breeds of, when
crossed, i. 279; with the plumage of
Anas boschas, i. 280 ; Malayan penguin,
identical in plumage with English, i.
280; characters of the breeds of, i. 281-
284; eges of, i. 281; effects of use and
disuse in, i. 284-286, ii. 298; feral, in
Norfolk, i. 190; Aylesbury, inheritance
of early hatching by, ii. 25; reversion
in, produced by crossing, ii. 40; wild-
ness of half-bred wild, ii. 45; hybrids
of, with the musk duck, ii. 45-46; as-
sumption of male plumage by, ii. 51;
crossing of Labrador and penguin, ii.
97; increased fertility of, by domesti-
cation, ii. 112; general fertility of, in
confinement, ii. 157; increase of size
of, by care in breeding, ii. 199 ; change
produced by domestication in, ii. 262,

Duminit, Aug., breeding of Siredon in
the branchiferous stage, ii. 384.

Dvy-coloured horses, origin of, i. 59.

Dvreat de la Malle, feral pigs in Louisi«
ana, il. 33; feral fowls in Africa, ¢bid. ;
bud-variation in the pear, i. 876; pro-
duction of mules among the Romays,
ii. 110.

Dusicyon sylvestris, i. 23.

Dortca rabbit, i. 107.

Dvtcu roller pigeon, i. 151,

Dvurrocuet, pelorism in the laburnum, ii.
346.

Dvuvat, growth of pears in woods in
France, ii. 260.

Dovau-Jouve, on Leersia oryzoides, ii.
91.

Dovernoy, self-impotence in Lilium can-
didum, ii. 137.

Dzierzon, variability in the characters
and habits of bees, i. 298.

Earwe, Dr., on colour-blindness, ii. 72,
328.

Ears, of fancy rabbits, i. 106; deficiency
of, in breeds of rabbits, i. 108; rudi-
mentary, in Chinese sheep, ii. 310;
drooping, ii. 801; fusion of, ii. 341.

Eaton, J. M., on fancy pigeons, i. 148,
153; variability of characters in breeds
of pigeons, i. 161; reversion of crossed
pigeons to coloration of Columba livia,
i. 198; on pigeon-fancying, i. 206, 215-
216; on tumbler-pigeons, i. 209, ii. 242;
carrier-pigeon, i. 211; effects of inter-
breeding on pigeons, ii. 126; properties
of pigeons, ii. 197-198; death of short-

‘allies

ECHINODERMATA.

INDEX. FALCO, 449

faced tumblers in the egg, ii. 226;
Archangel pigeon, ii. 240. :

EcHINODERMATA, metagenesis in, ii. 367.

Ectopistes, specific difference in number
of tail-feathers in, i. 159.

Ectopistes migratorius, sterile hybrids of,
with Turtur vulgaris, i. 193.

Epentata, correlation of dermal system

.and teeth in the, ii. 328.

EperwortuH, Mr., use of grass-seeds as
food in the Punjab, i. 309.

Epmonston, Dr.,on the stomach in Larus
argentatus and the raven, ii. 302.

Epwarps and Coty, on English wheat
in France, ii. 307.

Epwarps, W. F., absorption of the mi-
nority in crossed races, ii. 87.

Epwarps, W. W., occurrence of stripes
in a nearly thoroughbred horse, i. 57;
in foals of racehorses, i. 59.

Kees, of fowls, characters of, i. 248; va-
riations of, in ducks, i. 281; of the silk-
moth, i. 301.

Keyprt, ancient dogs of, i. 17-18; ancient
domestication of the pigeon in, i. 204;
absence of the fowl in ancient, i.
246.

E@yPrian goose, hybrids of, with penguin
duck, i. 282.

EHRENBERG, Prof., multiple origin of the
dog, i. 16; dogs of Lower Egypt, i. 25;
mummies of Felis maniculata, i. 43.

ELEMENT, male, compared to a premature
larva, ii. 384.

Evements of the body, functional inde-
pendence of the, ii. 868-371.

Exepuant, its sterility in captivity, ii.
150.

ELK, Irish, correlations in the, ii. 333-
334.

Eviror, Sir Walter, on striped horses, i.
58; Indian domestic and wild swine,
i. 66; pigeons from Cairo and Constan-
tinople, i. 132; fantail pigeons, i. 146;
Lotan tumbler pigeons, i. 150; a pigeon
uttering the sound Yahu, i155; Gal-
lus bankiva in Pegu, i. 236.

Euuis, Mr., varieties of cultivated plants
in Tahiti, ii. 256.

ELM, nearly evergreen Cornish variety of
the, i. 363, ii. 310; foliage-varieties of
the, i. 362.

ELM, weeping, i. 361; not reproduced by
seed, ii. 19,

Emberiza passerina, ii. 158.

Empryos, similarity of, i. 12; fusion of,
ii. 339.

Encex, on Laurus sassafras, ii. 274.

ENGLAND, domestication of Bos longifrons
in, 1. 81; selection of horses in, in me-
dizeval times, ii. 203; laws against the
early slaughter of rams in, ii, 203,

VOGT

EPHEMERIDé, development of the, ii. 366.

Epidendrum cinnabarinum and E. zebra,
li. 134.

Kipriepsy, hereditary, ii, 8, 78.

Erpt, disease of the white parts of cattle,
ii. 337.

Ericace”®, frequency of contabescence in
the, ii. 165,

ERICHTHONIUS, an improver of horges by
selection, ii. 202.

Iran, on the fat-tailed Kirghisian sheep,
i. 98, ii. 280; on the dogs of the Os-
tyaks, ii. 206.

Erodium, ii. 59.

Lrythrina Crista-galli and EF, herbacea,
hybrids of, ii, 265.

Esquinant, Mr., on the naked young of
dun-coloured pigeons, i. 170.

Esquimatx dogs, their resemblance to
wolves, i. 21; selection of, ii. 206.

EupEs-DEsLONGCHAMPS, on appendages
under the jaw of pigs, i. 75-76.

Euonymus Jxponicus, i. 383.

EvROPEAN cultivated plants, still wild in
Kurope, i. 307.

Evans, Mr., on the Lotan tumbler pigeon,
i. 150.

EVELYN, pansies grown in his garden, i.
368.

Evunrest, R., on the Newfoundland dog
in India, i. 36, ii. 305 ; degeneration of
setters in India, i. 38; Indian wild
boars, i. 66.

Ewes, hornless, ii. 350.

Extincrion of domestic races, i. 221.

lives, hereditary peculiarities of the, ii.
8-10; loss of, causing mierophthalmia
in children, ii. 24; modification of the
structure of, by natural selection, ii.
222-223 ; fusion of, ii. 341.

Eyrsrows, hereditary elongation of hairs
in, ii. 8.

Eyeuips, inherited peculiarities of the,
ii. 8,

Eyton, Mr., on gestation in the dog, i.
30; variability in number of vertebrae
in the pig, i. 74 ; individual sterility, ii.
162.

Faba vulgaris, i. 380.

Fasre, observations on A%gilops triti-
coides, i, 313.

Fagus sylvatica, ii. 19.

Farrweatuer, Mr., production of double
flowers from old seed, ii. 167.

Falco albidus, resumption of young plu-
mage by, in captivity, ii. 158.

Falco ossifragus, ii. 230.

Palco subbuteo, copulating in captivity, ii.
154.

Falco tinnunculus, breeding in captivity,
li. 154.

2-6

450

FALCONER.

INDEX.

FLOURENS.

89; selection of the silkworm in India,
i. 301 ; fastigate apple-trees in Calcutta,
i. 361 ; reproduction of a supernumerary
thumb after amputation, ii. 14 ; fertility
of the dhole in captivity, ii. 151; fer-
tility of English dogs in India, ii. 161 ;
sterility of the tiger m captivity, ii.
151; turkeys at Delhi, ii. 161; on In-
dian cultivated plants, ii. 165; Thibet
mastiff and goat, ii. 278.

Fatcons, sterility of, in captivity, ii. 153.

FALKLAND Islands, horses of the, i. 52-53,

61; feral pigs of the, i. 77; feral cattle

of the, i. 82, 86; feral rabbits of the, i.
112.

Fautow deer, ii, 108, 120.

FANTAIL pigeons, i. 146-148, ii. 227; fi-
gured, i. 147; furcula of, figured, i.
167; history of, i. 208; absence of oil-
gland in, ii. 344.

Farok Islands, pigeons of the, i. 183.

Fasuion, influence of, in breeding, ii.
240.

FAstIGatE trees, ii. 277, 348.

Faunas, geographical ditferences, of, i.
10.

“ WavouritE” bull, ii. 65, 118.

Featuers, homologous variation in, ii.
325.

Fret, of pigeons, individual differences of,
i. 160; correlations of external* cha-
racters in, i. 170-171.

Fret and beak, correlation of, in pigeons,
i. 171-174,

Fein, fertility of, in captivity, il.
15605" =

Felis bubastes, i. 43.

Felis caffra, i. 44.

Felis caliqulata, i. 43.

Felis chaus, i. 43-44.

Felis jubata, ii. 151.

Felis lybica, i. 44.

Felis maniculata, i. 43.

Felis manul, i. 45.

Felis ornata, i. 45.

Felis sylvestris, i. 44.

Felis torquata, i. 45.

Fema ts, affected by male element, ii. 365,

387-388.
Fermate flowers, in male panicle of maize,

i, 321;

Fennet, [talian variety of, i. 326.

Ferat cats, i. 47; cattle, i. 86; rabbits,
i. 111-115; Guinea fowl, i. 294; ani-
mals and plants, reversion in, li. 32-34,
47,

Frercuson, Mr., supposed plurality of

origin of domestic fowls, i. 231; chickens |
of black game-fowls, i. 244; relative |

size of eggs of fowls, i. 248; yolk of
eggs of game-fowls, i. 249; early pug-
nacity of game-cocks, i. 250; voice of
the Malay fowl, i. 259; effects of inter-
breeding on fowls, ii. 124; selection in
Cochin China fowls, ii. 196; on fashion
in poultry, ii. 240.

FERNANDEZ, on Mexican dogs, i. 23.

Ferns, reproduction of abnormal forms
of, by spores, i. 383; non-diffusion of
cell-gemmules in, ii, 379.

Ferrets, ii. 111, 151, 206.

| Fertisisavion, artificial, of the St. Valery

apple, i. 350.

FeErri.ity, various degrees of, in sheep, i.
97; unlimited mutual, of breeds of pi-
geons, i. 192-194 ; comparative of mon-
grels and hybrids, ii. 100-101, 178-
180; influence of nourishment on, ii.
111; diminished by close interbreeding,
ii, 118, 175; reduced, of Chillingham
wild cattle, ii. 119; of domesticated
varieties when crossed, ii. 189.

Festuca, species of, propagated by bulb-
lets, ii. 170.

Finperts, spared by tomtits, ii. 231.

Fieri, on the breeding of branchiferous
tritons, ii. 884.

Fincugs, general sterility of, in captivity,
ii. 154,

FInnigw (pigeon), i. 156.

FINNOoOoHIO, i. 326.

Fir, Scotch, acclimatisation of, ii. 310.

Fisu, Mr., advantage of change of soil to
plants, ii. 147.

Fisues, regeneration of portions of fins of,
ii. 15; variability of, when kept in
tanks, ii. 259; marine, living in fresh
water, ii. 304; double monsters of, ii.
340.

Fission and gemmation, ii. 358.

Frron, Mr., persistency of a variety of
the pea, i. 329.

Firrest, survival of the, i. 6.

Frrzrneer, origin of sheep, i. 94; African
maned sheep, i. 96.

Frxepness of character, conditions of, dis-
cussed, ii. 62-64.

| Fuax, found in the Swiss lake-dwellings,

i. 317; climatal difference in products
of, ii. 274,
Fuvece, fineness of, in Austrian merinos,
ii. 197.

FLEIscHMANN, on German sheep crossed
with merinos, ii. 88-89.

‘‘ FLORENTINER-T'AUBE,” i. 142-143.

FLOUNDER, li. 53. ;

Fiourens, crossing of wolf and dog, 1.
32; prepotency of the jackal over the
dog, ii. 67; hybrids of the horse and
ass, ii. 68; breeding of monkeys in
Europe, ii. 158.

FLOWER-GAKDEN. INDEX. GALEOBDOLON. 451
ees earliest known, in Eu- liable to suffer from frost, ii, 306; Polish,
rope, ii. 217. peculiarities of skull of, ii, 332-333.

FLowers, capricious transmission of | Fox, sterility of, in captivity, ii. 151.
colour-varieties in, ii. 20-21; tendency | Fox, S. Bevan, races of bees, i. 298,
to uniformity in striped, ii. 70; scorch- | Fox, W. Darwin, gestation of the dog, i,

iene AA a,

ing of, dependent on colour, ii. 229 ; Sees Negro = cat, i. 46; reversion of

change in, caused by conditions of life, sheep in colour, ll. 30; period of ges-

ii. 273; rudimentary, ii. 316; relative tation in the pig, i. 74; young of the

position of, to the axis, ii. 345. | Himalayan rabbit, i. 109; crossing of
Faration, abdominal, ii. 294. wild and domestic turkeys, i. 292; re-
Fotry, Mr., wild varieties of pears, ii. version in crossed musk ducks, ii. 40 ;

260. spontaneous segregation of varieties of
Foie, inherited peculiarities of, i. 362; geese, il. 104; effects of close inter-

variegation, of, i, 8366; bud-variation breeding upon bloodhounds, ii. 121;

in, i. 382-384. deafness of white cats with blue eyes,
Foop, influence of, on the pig, i. 72; on li, 329,

cattle, i. 91; excess of, a cause of va- FoxHounps, i. 40, ii. 120.

riability, ii. 257. Fragaria chiloensis, i. 351.

Forsgs, D., on Chilian sheep, i. 95; on Fragaria collina, i. 351.
the horses of Spain, Chili, and the Fragaria dioica of Duchesne, i. 353.
Pampas, i. 52. Fragaria elatior, i. 351.
Formica rufa, ii. 251. Fragaria grandiflora, i, 351,
Fortuns, R., sterility of the sweet potato Fragaria vesca, i. 351,
in China, ii. 169 ; development of axil- Fragaria virginiana, i. 351.
lary bulbs in the yam, ibid. Fraxinus excelsior, i. 360, 362, ii. 19.
FowL, common, breeds of, i. 225-230; | Fraxinus lentiscifolia, ii. 19.
supposed plurality of origin, i, 230; | Frrestanp cattle, probably descended
early history of, i. 231-233; causes from Bos primigenius, i. 81.
of production of breeds of, i. 233; | Frm.Back (pigeon), i. 155; Indian, i.
origin of from Gallus bankiva, i. 236- 153.
239, 245; feral, notices of, i. 237-238 ; Fringilla ciris, ii. 154.
reversion and analogous variation in, Fringilla spinus, ii. 154.
i, 239-246, ii. 35, 38, 39, 40, 349, 350; | Frizzizp fowls, i. 230; horses, i, 54.
“ cuckoo ” sub-breeds of, i. 244; history Frog, polydactylism in the, ii. 14.
of, i. 246-247; structural characters of, | Frurr, seedless, ii. 168.
i, 247-250 ; sexual peculiarities of, i. FRUIT-TREES, varicties of, occurring wild,
251-257, ii. 74; external differences of, i. 310.
i. 257-260; differences of breeds of, | Fry, Mr., on fertile hybrid cats, i. 44: on
from G. bankiva, i. 260; osteological feral fowls in Ascension, i. 238.
characters of, i. 260-270; effects of dis- Fucustas, origin of, i. 364; bud-variation
use of parts in, i, 270-274, ii. 298 ; feral, in, i, 382.
i. 190, ii. 33; polydactylism in, ii. 14; | Fuchsia coccinea and fulgens, twin seed
fertility of, increased by domestication, produced by crossing, i. 391,
ii. 112, 167; sterility of, under certain Furcrans, their superstition about killing
conditions, ii. 162 ; influence of selec- young water-fowl, i. 310; selection of
tion on, ii. 196, 198, 209, 210; evils of dogs by the, ii. 207 ; their comparative
close interbreeding of, ii. 124-125 ; estimation of dogs and old women, ii.
crossing of; ii. 95, 96, 97; prepotency 215; their power of distant vision, ii.
of transmission in, ii. 67; rudimentary 223.
organs in, ii, 315; crossing of hon-sitting | Fwuner, parasitic, ii. 284-285.
varieties of, ii, 43-44; homology of Furovna, characters and variations of the,
wing and leg feathers in, ii. 323; hy- in pigeons, i. 167; alteration of, by
brids of, with pheasants and Gallus disuse, in pigeons, i, 175; characters
Sonneratii, ii. 45; black-skinned, ii, of, in fowls, i. 268.
209-210; black, preyed upon by the | Fuston of homologous parts, ii. 393.
osprey in Iceland, ii. 230; five-toed,
mentioned by Columella, ii. 429 ; rump-
less, tailed chickens, produced by, ii.
31; Dorking, crosses of, ii.93; form of
comb and colour of plumage in, ii. 238 - fauna and flora, i. 9.
game, crossing of white and black, ii. | Galeobdolon luteum, pelorism in, ii. 59
92; five-spurred, ii. 391; Spanish, 345. ;

a2

a I

Garr, inheritance of peculiarities of, ii.
6

GaLapacos Archipelago, its peculiar

|
|
|
|

452,

GALLS, ii. 282-284.

GALL-GNATS, ii. 283.

eee excrescences not inherited, ii.

GALLINACEOUs birds, restricted range of
large, i, 237; general fertility of in cap-
tivity, ii. 155.

Gallinula chloropus, ii. 156.

Gallinula nesiotis, i. 287.

GALTON, Mr., fondness of savages for
taming animals, i. 20, ii. 160; cattle of
Benguela, i. 88; on hereditary talent,
ae

GALLESIO, species of oranges, i. 334, 335, |
336; hybridisation of oranges, i. 336;
persistency of races in the peach, i.
339; supposed specific distinctions of
peach and nectarine, i. 340; Bizzaria
orange, i. 391 ; crossing of red and white |
carnations, i. 393; crossing of the
orange and lemon, i, 399, ii. 365;
effect of foreign pollen on maize, i. 400 ;
spontaneous crossing of oranges, ii. 91;
monstrosities a cause of sterility in
plants, ii. 166; seeding of ordinarily
seedless fruits, ii..168; sterility of the
sugar cane, ii. 169; tendency of male
flowers to become double, ii. 171; effects
of selection in enlarging fruit, &ce., ii.
217; variation of the orange tree in
North Italy, ii. 256; naturalisation of
the orange in Italy, ii. 309.

Gallus xneus, a hybrid of G. varius and
the domestic fowl, i. 235.

Gallus bankiva, probable original of do-
mestic fowls, 1.233, 236-239, 245; game-
towl, nearest to, i. 226; crossed with:
G. Sonneratii, i. 234; its character and
habits, i. 235-236, ii. 109; differences
of various breeds of fowls from, i. 260;
occipital foramen of, figured, i. 261;
skull of, figured,i. 262 ; cervical vertebra
of, figured, i. 267; furcula of, figured,
i. 268; reversion to, in crossed fowls,
ii. 39-40; hybrid of, with G. varius, i.
235, ii. 40; number of eggs of, ii. 112.

Gallus ferrugineus, i. 226.

Gallus furcatus, i. 234.

Gallus giganteus, i. 235.

Gallus Sonneratii, characters and habits
of, i). 2333 hybrids: of, i.. 234, ii.
45.

Gallus Stanleyi, hybrids of, i. 234.

Gallus Temminckit, probably a hybrid, i.
235.

Gallus varius, character and. habits of, i.
234; hybrids and probable hybrids of,
i. 234-235,

Gampier, Lord, his early cultivation of
the pansy, i. 368.

GAME-FOWL, i. 226, 250, 251, 252.

INDEX.

GEMMATION,

GaARCcILAZO de la Vega, annual hunts of
the Peruvian Ineas, ii. 207.

Garnett, Mr., migratory propensities of
hybrid ducks, ii. 45.

Garrop, Dr., on hereditary gout, ii. 7.

GASPARINI, a genus of pumpkins, founded
on stigmatic characters, 1. 359.

GAUDICHAUD, bud-variation in the pear,
i. 376; apple tree with two kinds of
fruit on branch, i. 392.

GauprY, anomalous structure in the feet
of horses, i. 50.

Gay, on Fragaria grandiflora, i. 351;
on Viola lutea and tricolor, i. 368; on
the nectary of Viola grandiflora, i.
369.

GAYAL, domestication of the, i. 82.

Gayot, see Moll.

GARTNER, on the sterility of hybrids, i.
192, ii. 101; acquired sterility of varie-
ties of plants when crossed, i. 358;
sterility in transplanted plants, and in
the lilac in Germany, ii. 164; mutual
sterility of blue and red flowers of the
pimpernel, ii. 190; supposed rules of
transmission in crossing plants, ii. 68 ;
on crossing plants, ii. 98, 127, 130, 131;
on repeated crossing, ii. 267; absorp-
tion of one species by another, when
crossed, ii. 88 ; crossing of varieties of
the pea, i. 397; crossing maize, ii. 105;
crossing of species of Verbascum, ii. 93,
105; reversion in hybrids, ii. 36, 49,
50; of Cereus, i. 892; of Tropxolum
majus and minus, i. 392; variability of
hybrids, ii. 265; variable hybrids from
one variable parent, ii. 270; graft
hybrid produced by inosculation in the
vine, i. 395; effect produced by grafts
on the stock, i. 394, ii. 278; tendency
of hybrid plants to produce double
flowers, ii. 171; production of perfect
fruit by sterile hybrids, ii. 172; sexual
elective aftinity, ii. 180; self-impo-
tence in Lobelia, Verbascum, Lilium,
and Passiflora, ii. 136-137; on the
action of pollen, ii. 108; fertilisation
of Malva, i. 402-403, ii. 363; prepo-
tency of pollen, ii. 187; prepotency
of transmission in species of Nicotiana,
ii, 67; bud-variation in Pelargonium
zonale, i. 875; in CGinothera biennis, 1.
382; in Achillea millefolium, i. 408;
effect of manure on the fertility of
plants, ii. 163; on contabescence, HU.
165-166; inheritance of plasticity, 1.
241; villosity of plants, ii. 277. :

GEESE (anseres) general fertility of, im
captivity, ii. 157. BEEN

(GimcENBAUR, on the number of digits, 11.
13.

GAPES, ii. 228.

GremMMATION and fission, ii. 358.

GEMMULES.

INDEX.

GODRON. 453

GEMMULES, or cell-gemmules, ii. 374, 378-
381, 384. “Sas

GENET, tertility of the, in captivity, ii.
151.

GENERATION, alternate, ii. 8361, 367, 890.

GENERATION, sexual, ii. 359-364,

Gentus, inheritance of, ii. 7.

Gentiana amarella, ti, 168.

Grorrroy Saint-Hilaire, production of
monstrous chickens, ii. 289; “ Loi de
Vafinité de soi pour soi,” ii. 839; com-
pensation of growth, ii. 342.

Grorrroy Saint-Hilaire, Isid., origin of
the dog, i. 66; barking of a jackal, i.
27 ; period of gestation and odour of
the jackal, i. 830; anomalies in the
teeth of dogs, i. 34; variations in the
proportions of dogs, i. 35; webbed feet
of Newfoundland dogs, i. 39; crossing
of domestic and wild cats, i. 44; domes-
tication of the arni, i, 82; supposed
introduction of cattle into Europe from
the East, ibid.; absence of interdigital
pits in sheep, i. 95; origin of the goat,
1. 101; feral geese, 1.190; ancient his-
tory of the fowl, i. 246; skull of the
Polish fowl, i. 262; preference of the
Romans for the liver of white geese, i.
289; polydactylism, ii. 12; assumption
of male characters by female birds, ii.
51; supernumerary mamme in women,
li, 58; development of a proboscis in
the pig, ibid.; transmission and blend-
ing of characters in hybrids, ii. 94;
refusal of animals to breed in captivity,
ii. 149; on the Guinea pig, ii. 152;
silkworms producing white cocoons, ii.
199; on the carp, ii. 236; on Helix
lactea, ii. 280; on monstrosities, ii.
254; injury to the embryo a cause
of monstrosity, ii, 269; alteration in
the coat of horses in coal mines, ii.
278; length of the intestines in wild
and tame animals, ii, 302-303; inherit-
ance of rudimentary limbs in the dog,
ii. 815; correlation in monstrosities, ii.
320; supernumerary digits in man, ii.
322; co-existence of anomalies, ii. 331;
fusion of homologous parts, ii. 341-342 :
presence of hairs and teeth in ovarian
tumours, ii. 370; development of teeth
on the palate in the horse, ii, oot:

GEOGRAPHICAL differences of faunas, i. 10.

GEOLOGICAL succession of organisms, i. 1],

Geranium, li. 59.

Geranium pheum and pyrenaicum, ii. 258.

Geranium pratense, i. 379.

GERARD, asserted climatal change in
Burgundian bees, i. 297,

GERARDE, on varieties of the hyacinth, i.
370.

GERSTACKER, on hive-bees, i, 299,

|

Gervais, Prof, origin of the dog, i. 16;
resemblance of dogs and jackals, i,
24; taming of the jackal, i. 26; num-
ber of teeth in dogs, i, 34; breeds of
dogs, i. 36; on tertiary horses, i. 51;
biblical notices of horses, i. 55; species
of Ovis, i. 94; wild and domestic rab-
bits, i. 103; rabbits from Mount Sinai
and Algeria, i. 105; earless rabbits, i.
108; batrachia with doubled limbs, ii,
391.

Gustation, period of, in the dog, wolf,
&ec., i. 29-30 ; in the pig, i. 74; in cattle,
i. 87, ii. 321; in sheep, i. 97.

GxsturES, inheritance of peculiarities in,
3,6.

“ GHoonpoors” a sub-breed of fowls, i.
229.

Guor-Kuvr, ii. 42.

Giius, Mr., effect of cross-breeding in the
pig, i. 404.

G1R4FFE, co-ordination of structure of, ii.
221.

GiraRD, period of appearance of perma-
nent teeth in dogs, i. 35.

Girou de Buzareingues, inheritance in
the horse, ii. 10; reversion by age in
cattle, ii. 38; prepotency of iransmis-
sion of character in sheep and cattle, ii.
66; on crossing gourds, ii. 108.

GISBURNE, wild cattle at, i. 84.

Gladiolus, i. 364; self-impotence of
hybrids of, ii. 139.

Gladiolus colvillii, bud-variation in, i. 882.

GLANDS, compensatory development of, ii.
800.

Guasronpury thorn, i. 864.

GLENny, Mr., on the Cineraria, ii. 200.

GLoEDE, F’., on strawberries, i. 353.

GuoGER, on the wings of ducks, ii. 298.

“GLOUGLOU ” (pigeon), i. 154.

Gloxinix, peloric, i. 365, ii. 167.

GMELIN, on red cats, at Tobolsk, i. 47.

Goat, i. 101-102, ii. 83; polydactylism
in the, ii. 14; sexual differences in horns
of, ii. 73; valued by South Africans, ii.
207; Thibet, ii. 278; amount of milk
and development of udders in the, ii.
300; hornless, rudimentary bony cores
in, ii. 316; Angora, ii. 326.

Gopron, odour of the hairless Turkish
dog, i. 80; differences in the skull of
dogs, i. 84; increase of breeds of horses,
i. 51; crcssing of domestic and wild
swine, i, 66; on goats, i. 101-102 ; colour
of the skin in fowls, i. 258; bees of
north and south of France, i. 297; in-
troduction of the silkworm into Europe,
i, 300; variability in the silkworm, i.
304; supposed species of wheat, i. 812-
314; on Agilops triticoides, i. 313;
variable presence of barbs in grasses, i.

454

314; colours of the seeds of maize, i.
321; unity of character in cabbages,
i. 323; correlation of colour and odour,
i. 325; effect of heat and moisture on
the cabbage, i. 8325; on the cultivated
species of Brassica, i. 325 ; on the Roun-
cival and sugar peas, i. 327; variation
in the numbers of peas in the same pod,
i. 828; wild vines in Spain, i. 332; on
raising peaches from seed, i. 339 ; sup-
posed specific distinctness of peach and
nectarine, i. 340; nectarine producing
peaches, i. 341; on the flower of Cory-
dalis, i. 344; origin and variations of
the plum, i. 345; origin of the cherry,
i. 347; reversion of single - leaved
strawberries, i. 353; five-leaved va-
riety of Fragaria collina, i. 353; sup-
posed immutability of specific charac-
ters, i. 358-359; varieties of Robinia, i.
361; permanency of the simple-leaved
ash, i. 362; non-inheritance of certain
mutilations, ii. 23; wild turnips, car-
rots, and celery, ii.33; pre-potency of a
goat-like ram, ii. 66; benefit of change
of soil to plants, ii. 146; fertility of
peloric flowers of Corydalis solida, ii.
167; seeding of ordinarily seedless
fruit, ii. 168; sexual sterility of plants
propagated by buds, &., ii. 169; in-
crease of sugar in beet-root, ii. 201;
effects of selection in enlarging par-
ticular parts of plants, ii. 217; growth
of the cabbage in the tropics, ii. 277;
rejection of bitter almonds by mice, ii.
232; influence of marshy pasture on
the fleece of sheep, ii. 278; on the ears
of ancient Egyptian pigs, ii. 301; pri-
mitive distinctness of species, ii. 415;
solid- hoofed swine, ii. 429.

GOETHE, on compensation of growth, ii.342.

GOLDFISH, i, 296-297, ii. 236.

Gomara, on South American cats, i. 46.

GonGorA, number of seeds in the, ii. 379.

GoosE, ancient domestication of, i. 287;
sacred to Juno in Rome, ibid.; inflexi-
bility of organisation of, i. 288; skull
perforated in tufted, i. 288; characters
of breeds and sub-breeds of, i. 288-289 ;
variety of, from Sebastopol, i. 289, ii.

GOETHE.

392; feral in La Plata, 1.190; Egyp- |

tian, hybrid of, with penguin duck, ii.
68; spontaneous segregation of va-
rieties of, ii. 104; fertility of, increased
by domestication, ii. 112; decreased

fertility of, in Bogota, ii. 161; sterility |

of, in the Philippine Islands, ii. 162;
selection of, ii. 204; white, preference

of the Romans for the liver of, ii. 209; |

persistency of character in, ii. 254;

Egyptian, change in breeding season of, |

ii. 304.

INDEX.

GREY.

GOOSEBERRY, 1. 354-356; bud-variation in
the, i. 376; Whitesmith’s, ii, 232,

GOPPERT, on monstrous poppies, ii. 166.

Gosse, P. H., feral dogs in Jamaica, i.
28; feral pigs of Jamaica, i. 77-78;
feral rabbits of Jamaica, i. 112; on
Columba leucocephala, i. 183; feral
Guinea fowl in Jamaica, i. 190; repro-
duction of individual peculiarities by
gemmation in a coral, 1.374; frequency
of striped legs in mules, ii. 42.

GovLp, Dr., on hereditary hemorrhage, ii.
hs

Goup, John, origin of the turkey, i. 292,

Goura coronata and Victoriz, hybrids of,
i. 194, ii. 155.

GourDs, i. 357; crossing of varieties of, ii,
108 ; ancient Peruvian variety of, ii. 429,

Govr, inheritance of, ii. 7; period of ap-
pearance of, ii. 77.

GraBa, on the pigeon of the Faroe islands,
i. 183.

GRAFTING, ii, 147; effects of, ii, 259, 278;
upon the stock, i. 394-395; upon the
variability of trees, ii. 259; changes
analogous to bud-variation produced by,
1, 387, 389.

GRAFT-HYBRIDS, i, 390-391, 394-397, ii.
364-365.

Grapes, bud-variation in, i. 8375; cross of
white and purple, i. 393; green, liable
to disease, ii. 336; effect of foreign
pollen on, i. 400.

Grasszs, seeds of, used as food by savages,
i. 807-309.

Gray, Asa, superior wild varieties of
fruit-trees, i. 310; cultivated native
plants of North America, i. 312, 357;
non-variation of weeds, i. 317; supposed
spontaneous crossing of pumpkins, i.
399; pre-ordination of variation, ii.
432; progeny of husked form of maize,
i. 320; wild intermediate forms of
strawberries, i. 352.

Gray, G. R., on Columba gymmnocyclus, 1.
184,

| Gray, J. E., on Sus pliciceps, i. 70; on a

variety of the gold-fish, i. 297; hybrids
of the ass and zebra, ii. 42-43; on the
breeding of animals at Knowsley, i.
149; on the breeding of birds in capti-
vity, ii. 157.
GREENE, J. Reay, on the development of
the echinodermata, ii. 367.
GrEENHOW, Mr., on a Canadian web-footed
dog, i. 39.
GREENING, Mr., experiments on Abraxas
grossulariata, ii. 280.
Grecson, Mr., experiments on Abraxas
grossulariata, ii. 280. :
Grey, Sir George, preservation of seed-
bearing plants by the Australian sa-

en ae

»

GREYHOUNDS.

vages, i. 310; detestation of incest by
Australian savages, li. 123. :

Greynounps, sculptured on Egyptian
monuments, and in the Villa of Anto-
ninus, i. 17; modern breed of, i 41;
crossed with the bulldog, by Lord
Orford, ii. 95; co-ordination of struc-
ture of, due to selection, ii. 221-222;
Italian, ii. 227.

Greyness, inherited at corresponding
periods of life, ii. 77.

GrizveE, Mr., on early-flowering dahlias,
i. 370. i

Grigor, Mr., acclimatisation of the Scotch
fir, ii. 310.

Groom-Nartsr, C. O., on the webbed feet
of the otter-hound, i. 40.

“ GROSSES-GORGES ” (pigeons), i. 137.

GROUND-TUMBLER, Indian, i. 150.

Grouse, fertility of, in captivity, ii. 156.

GRONLAND, hybrids of A/gilops and wheat,
ii. 110.

Grus montigresia, cinerea, and Antigone,
ii. 156.

Guanacos, selection of, ii. 207.

Guans, general fertility of, in captivity, ii.
156.

GUELDER-ROSE, ii. 185.

GUELDERLAND fowls, i. 230.

Gutana, selection of dogs by the Indians
of, ii. 206.

GuINEA fowl, i. 294; feral in Ascension,
and Jamaica, i. 190, ii. 833; indifference
of to change of climate, ii. 161.

GUINEA pig, ii. 24, 152,

GULDENSTADT, on the jackal, i. 25.

GULL, herring, breeding in confinement,
ii. 157,

GULLS, general sterility of, in captivity, ii.
157.

Gulo, sterility of, in captivity, ii. 152.

Ginruer, A., on tufted ducks and geese,
i. 274; on the regeneration of lost parts
in batrachia, ii. 15.

Gurney, Mr., owls breeding in captivity, ii.

154; appearance of ‘black-shouldered”’

among ordinary peacocks, i. 291.

Hazit, influence of, in acclimatisation,
ii. 312-315.

Hasits, inheritance of, ii. 8395.

HACKEL, on cells, ii. 370; on the double
reproduction of meduse, ii. 384; on
inheritance, ii. 397.

Hack.ks, peculiarities of, in fowls, i. 254.

Hair, on the face, inheritance of, in man,
ii. 4; peculiar lock of, inherited, ii. 5;
growth of, under stimulation of skin,
ii. 326; homologous variation of, ii,
325 ; development of, within the ears
and in the brain, ii. 391.

Harr and teeth, correlation of, i1. 326-328, |

INDEX. | HEAD. 455

Harry family, corresponding period of in-
heritance in, ii. 77.

HAur-castes, character of, ii. 46.

Haur-1o0p rabbits, figured and described,
i. 107-108; skull of, i. 119.

Halixtus leucocephalus, copulating in
captivity, ii. 154,

Hauiam, Col., on a two-legged race of
pigs, li. 4.

HamevrcH fowl, i. 227, 261; figured, i.
228.

Hamiiron, wild cattle of, i. 84.
HamitTon, Dr., on the assumption of male
plumage by the hen pheasant, ii. 51.
Haminron, F. Buchanan, on the shad-
dock, i. 335; varieties of Indian culti-

vated plants, ii. 256.

Hancocr, Mr., sterility of tamed birds, ii.
155-157.

Hanpwritin¢, inheritance of peculiarities
in, ii. 6.

Hanmer, Sir J., on selection of flower
seeds, ii. 204.

HaAnsEx1, Mr., inheritance of dark yolks:
in duck’s eggs, i. 281.

Harcourt, E. V., on the Arab _ boar-
hound, i. 17; aversion of the Arabs to
dun-coloured horses, i. 55.

Harpy, Mr., effect of excess of nourish-
ment on plants, ii. 257.

Hare, hybrids of, with rabbit, i. 105;
sterility of the, in confinement, ii. 152;
preference of, for particular plants, ii.
232.

Hare-.ip, inheritance of, ii. 24.

Haran, Dr., on hereditary diseases, il. 7.

Hanmer, Mr., on the number of eggs in a
codfish, ii. 379.

Harvey, Mr., monstrous red and white
African bull, i. 91.

Harvey, Prof., singular form of Begonia
frigida, i. 365-366; effects of cross-
breeding on the female, i. 404; mon-
strous saxifrage, ii. 166.

Hasora wheat, i. 313.

Havrtsots strawberry, i. 353.

Hawker, Col., on call or decoy ducks, i.
281.

Hawtnorn, varieties of, i. 360-364; py-
ramidal, i. 361; pendulous hybridised,
ii. 18; changes of, by age, 1. 364, 387;
bud-variation in the, i. 377; flower
buds of, attacked by bullfinches, ii. 232.

Havers, Dr., character of Esquimaux dogs,
i, 21-22.

Haywoop, W., on the feral rabbits of
Porto Santo, i. 114.

Hazen, purple-leaved, i. 362, 395, ii, 330.

Heap of wild boar and Yorkshire pig,
figured, i. 72. :

Hap and limbs, correlated variability of,

ii. 323.

456

HEADACHE.

INDEX.

HODGKIN.

HEADACHE, inheritance of, ii. 79,

HearTsEAsE, i. 368-369; change pro-
duced in the, by transplantation, i. 886 ;
reversion in, ii. 31, 47; effects of selec-
tion on, ii. 200; scorching of, ii, 229;
effects of seasonal conditions on the, ii.
274; annual varieties of the, ii. 305.

Huat, effect of, upon the fleece of sheep,
i. 98,

Heper, Bishop, on the breeding of the
rhinoceros in captivity, ii. 150.

Hesripes, cattle of the, i. 80; pigeons of
the, i, 183, ;

Herr, O., on the plants of the Swiss lake-
dwellings, i. 309, ii. 215, 427; on the
cereals, 1. 317-319 ; on the peas, i. 326;
on the vine growing in Italy in the
bronze age, i. 332.

Helix lactea, ii. 280.

Hemerocallis fulva and flava, interchang-
ing by bud-variation, i. 386.

Hermuock yields no conicine in Scotland,
ii. 274.

Hemp, differences of, in various parts of
India, ii. 165; climatal difference in
products of, ii. 274.

Hempseen, efiect of, upon the colour of
birds, ii. 280.

HERMAPHRODITE flowers, occurrence of, in
Maize, i. 321.

Hen, assumption of male characters by
the, ii. 51, 54; development of spurs
in the, ii. 318.

“ Henntes,” or hen-like male fowls, i. 252.

Henry, T. A., a variety of the ash pro-
duced by grafting, i.394; crossing of spe-
cies of Rhododendron and Arabis, i. 400.

Henstow, Prof., individual variation in
wheat, i, 314; bud-variation in the
Austrian bramble rose, i. 381; partial
reproduction of the weeping ash by
seed, ii. 19.

Hepatica, changed by transplantation, i.
386.

HERBERT, Dr., variations of Viola grandi-
jlora, i. 368; bud-variation in camel-
lias, i. 377; seedlings from reverted
Cytisus Adami, i. 388 ; crosses of Swedish
and. other turnips, ii. 93 ; on hollyhocks,
li. 107; breeding of hybrids, ii. 131;
self-impotence in hybrid hippeastrums,
li. 188-139 ; hybrid Gladiolus, ii. 139;
on Zephyranthes candida, ii. 164 ; ferti-
lity of the crocus, ii. 165; on conta-

bescence, ii. 165 ; hybrid Rhododendron,
li. 265.

Hercunanevm, figure of a pig found in,
i. 67.

Heron, Sir R., appearance of “ black-
shouldered” among ordinary peacocks,
i, 290-291 ; non-inheritance of monstrous
characters by goldfish, i. 296; crossing

of white and coloured Angora rabbits,
li. 92 ; crosses of solid-hoofed pigs, ii. 93.

Herpestes fasciatus and griseus, ii. 151.

HEuvsINGER, on the sheep of the Tarentino,
li. 227; on correlated constitutional
peculiarities, ii, 337.

Hewitt, Mr., reversion in bantam cocks,
i. 240; degeneration of silk fowls, i.
243; partial sterility of hen-like male
fowls, i. 252; production of tailed
chickens by rumpless fowls, i. 259; on
taming and rearing wild ducks, i. 278. .
279, ii, 233, 262-263; conditions of.
inheritance in laced Sebright bantams,
ii. 22; reversion in rumpless fowls, ii,
31; reversion in fowls by age, ii. 39;
hybrids of pheasant and fowl, ii. 45,
68; assumption of male characters by
female pheasants, ii. 51; development
of latent characters in a barren bantam
hen, ii. 54; mongrels from the silk-
fowl, ii. 67; effects of close inter-
breeding on fowls, ii. 124-125; on
feathered-legeed bantams, ii. 323.

Hipeert, Mr., on the pigs of the Shetland
Islands, i. 70.

HIGHLAND cattle, descended from Bos
longifrons, i. 81.

HILDEBRAND, Dr., on graft-hybrids with
the potato, i. 396; on the influence of
pollen on the mother-plant, i. 400; on
the fertilisation of Orchidex, i. 402-
403; occasional necessary crossing of
plants, ii. 90; on Primula sinensis and
Oxalis rosea, ii. 182; on Corydalis
cava, ii. 132-1338.

Hitt, R., on the Alco, i. 31; feral rabbits
in Jamaica, i. 112; feral peacocks in
Jamaica, i. 190; variation of the Guinea
fowl in Jamaica, i, 294; sterility of
tamed birds in Jamaica, ii. 155, 157.

HIMALAYA, range of gallinaceous birds in
wie. 41. 237.

HimMaLaYan rabbit, i. 107, 108-111 ; skull
of, i. 120.

HIMALAYAN sheep, i. 95.

Hinpmarsu, Mr., on Chillingham cattle,
i. 84.

“¢ HINKEL-T'avusg,” i. 142-143.

Hinny and mule, difference of, ii. 67-68.

Hipparion, anomalous resemblance to in
horses, i. 50.

Hippeastrum, hybrids of, ii, 138-139.

Hive-BEEs, ancient domestication of, i.
297; breeds of, i. 298; smaller when
produced in old combs, i. 297; varia-
bility in, i. 298; crossing of Ligurian
and common, i. 299,

* HockEer-TAvsE,”’ i. 141. a

Hosss, Fisher, on interbreeding pigs, Ui.
121. .

Hopexin, Dr., on the attraction of foxes

a

~

\

HODGSON. INDEX. HUNGARIAN, 457

by a female Dingo, i. 31; origin of the
Newfoundland dog, i. 42; transmission
of a peculiar lock of hair, ii. 5.
Hoveson, Mr., domestication of Canis
primexvus, i. 26; development of a fifth
digit in Thibet mastiffs, i. 85; number
of ribs in humped cattle, i. 79; on the
sheep of the Himalaya, i. 95; presence
of four mamme in sheep, ibid.; arched
nose in sheep, i. 96; measurements of
the intestines of goats, i. 102; presence
of interdigital pits in goats, ibid. ; dis-
use a cause of drooping ears, li. 301.

. HoFAcKER, persistency of colour in horses,

i, D1, ii. 21; production of dun horses
from parents of different colours, i. 59 ;
inheritance of peculiarities in hand-
writing, ii. 6; heredity in a one-horned
stag, li. 12; on consanguineous mar-
riages, ii. 123.

Hoe, Red River, ii. 150.

Hoee, Mr., retardation of breeding in
cows by hard living, ii, 112.

Ho ian, Sir H., necessity of inheritance,
ii. 2; on hereditary diseases, ii. 7;
hereditary peculiarity in the eyelid, ii.
8; morbid uniformity in the same
family, ii. 17; transmission of hydrocele
through the female, ii. 52; inheritance
of habits and tricks, ii. 395.

HO. y, varieties of the, i. 360, 362; bud-
reversion in, i. 384; yellow-berried, ii.
19, 230.

Hotuyxock, bud-variation in, i. 378 ; non-
crossing of double varieties of, ii. 107;
tender variety of the, ii. 310.

Homer, notice of Geese, i. 287; breeding
of the horses of Alneas, ii. 202.

Homo.ocots parts, correlated variability
of, ii, 322-331, 354-355; fusion of, -ii,
393; affinity of, ii, 389-342,

Hoors, correlated with Lair in variation,

- ti, 325.

HooK-BILLED duck, skull figured, i. 282.

Hooker, Dr. J. D., forked shoulder-stripe
in Syrian asses, i. 63; voice of the cock
in Sikkim, i. 259; use of Arum-roots as
food, i. 307; native useful plants of
Australia, i. 311; wild walnut of the
Himalayas, i. 356; variety of the plane
tree, i. 362; production of Thuja ori-
entalis from seeds of T. pendula, i. 362 ;
singular form of Begonia frigida, i. 365 ;
reversion in plants run wild, ii. 33; on
the sugar-cane, ii. 169; on Arctic plants,
ii. 256 ; on the oak grown at the Cape of
Good Hope, ii. 274; on Rhododendron
ciliatum, ii. 277 ; stock and mignonette,
perennial in Tasmania, ii. 305.

Hopxirk, Mr., bud-variation in the rose,
i, 381; in Mirabilis jalapa, i. 382; in
Convolvulus tricolor, i. 408.

Hornbean, heterophyllous, i. 362.

Horne fowl, i. 229 ; skull figured, i. 265.

HornteEss cattle in Paraguay, i. 89.

Horns of sheep, i. 95; correlation of,
with fleece in sheep, ii. 8326; corre-
lation of, with the skull, ii. 333; rudi-
mentary in young polled cattle, ii. 315;
of goats, i. 102.

Horses, in Swiss lake-dwellings, i. 49;
different breeds of, in Malay Archi-
pelago, i. 49; anomalies in osteology and
dentition of, i. 50; mutual fertility of
different breeds, i. 51; feral, i. 51; habit
of scraping away snow, i. 53; mode of
production of breeds of, i. 54; inherit-
ance and diversity of colour in, i. 55;
dark stripes in, i. 56-61, ii. 351; dun-
coloured, origin of, i. 59; colours of
feral, i. 60-61; effect of fecundation by
a Quagga on the subsequent progeny
of, i. 403-404; inheritance of peculi-
arities in, ii, 10-11; polydactylism in,
ii. 14; inheritance of colour in, ii. 21;
inheritance of exostoses in legs of, ii.
238; reversion in, ii. 33, 41; hybrids of,
with ass and zebra, ii. 42; prepotency
of transmission in the sexes of, ii. 65;
segregation of, in Paraguay, ii. 102;
wild species of, breeding in captivity, ii.
150; curly, in Paraguay, ii. 205, 325;
selection of, for trifling characters, ii.
209; unconscious selection of, ii. 212-
213; natural selection in Circassia,
ii. 225; alteration ‘of coat of, in coal-
mines, ii, 278; degeneration of, in the
Falkland Islands, ii. 278; diseases of,
caused by shoeing, ii. 300; feeding on
meat, ii. 305; white and white-spotted,
poisoned by mildewed vetches, ii. 337 ;
analogous variations in the colour of,
ii. 349; teeth developed on palate of,
ii. 891; of bronze period in Denmark,
ii. 427,

Horsk-cHESNUT, early, at the Tuileries,
i. 362; tendency to doubleness in, ii.
168.

Horsr-ravisH, general sterility of the, ii.
170.

“ Toupan,” a French sub-breed of fowls,
ipiaee.

Howarp, C., on an Egyptian monument,
i. 17; on crossing sheep, ii. 95, 120.

Huc, on the Emperor Khang-hi, ii. 205 ;
Chinese varieties of the bamboo, ii. 256.

Humepoipt, A., character of the Zambos,
ii. 47; parrot speaking the language
of an extinct tribe, ii. 154; on Pulea
penetrans, li. 275.

Homuiprry, injurious effect of, upon horses,
i. 53.

Humpureys, Col., on Ancon sheep, i. 100.

Huncarian cattle, i. 80.

458 HUNTER,

INDEX.

INSECTS.

Hunter, John, period of gestation in the
dog, i. 29; on secondary sexual cha-
racters, i. 179 ; fertile crossing of Anser
ferus and the domestic goose, i. 288;
inheritance of peculiarities in gestures,
voice, &¢., iil. 6; assumption of male
characters by the human female, ii,
51; period of appearance of hereditary
diseases, ii. 78; graft of the spur of a
cock upon its comb, ii. 296; on the
stomach of Larus tridentatus, ii. 302;
double-tailed lizards, ii. 341.

Hunter, W., evidence against the influ-
ence of imagination upon the offspring,
li. 264.

Hurton, Capt., on the variability of the
silk moth, i. 303; on the number of
species of silkworms, i. 300; markings
of silkworms, i. 302; domestication of
the rock-pigeon in India, i. 185; do-
mestication and crossing of Gallus
bankiva, 1. 236.

Hotcoutnson, Col., liability of dogs to
distemper, i. 35.

Hvuxteny, Prof. on the transmission of
polydactylism, ii. 13; on unconscious
selection, ii. 194; on correlation in the
mollusea, ii. 320; on gemmation and
fission, ii. 859; development of star-
fishes, li. 366.

Hyacinrus, i. 370-371; bud-variation in,
i, 885; graft-hybrid by union of half
bulbs of, i. 395; white, reproduced by
seed, ii. 20; red, ii, 229, 336; varieties
of, recognisable by the bulb, ii. 251.

Hyacintu, feather, ii. 185, 316.

Hyacinthus orientalis, i. 870.

Hybiscus syriacus, ii. 286.

Hysrins, of hare and rabbit, i. 105; of
various species of Gallus, i, 234-236;
of almond, peach, and nectarine, i. 339 ;
naturally produced, of species of Cytisus,
i, 390; from twin-seed of Fuchsia coc-
cinea and fulgens, i. 8391; reversion of,
i, 392-394, ii. 86. 48-50; from mare,
ass, and zebra, ii. 42; of tame animals,
wildness of, ii. 44-46; female instincts
of sterile male, ii.52; transmission and
blending of characters in, ii. 92-95;
breed better with parent species than
with each other, ii. 131; self-impo-
tence in, ii. 188-140; readily produced
in captivity, ii. 151.

Hypripisation, singular effects of, in
oranges, i. 336; of cherries, i. 347; dif-
ficulty of, in Cucurbita, i. 358; of roses,
i. 366.

Hiypripism, ii. 178-191; the cause of a
tendency to double flowers, ii. 171; in
relation to pangenesis, ii. 385.

Hysriniry in cats, i. 44-45; supposed of
peach and nectarine, i. 342.

Hydra, i. 374, ii. 298, 359.

HypraANnGEA, colour of flowers of, influ-
enced by alum, ii. 277.

Hyproce ep, ii, 52.

Hyprocepnatrs, ii. 295.

Hypericum calycinum, ii. 170.

Hypericum crispum, ii. 227, 337.

HYPERMETAMORPHOSIS, ii. 367.

HYPrEerMETRoPIA, hereditary, ii. 8.

ICHTHYOPTERYGIA, number of digits in.

the, ii. 16.

Llex aquifolium, ii. 19.

IMAGINATION, supposed effect of, on oft-
spring, ii. 268.

Imatophyllum miniatum, bud - variation
in, i. 385,

Incest, abhorred by savages, ii. 123-124,

Ixcusation, by crossed fowls of non-sit-
ting varieties, ii. 43-44,

Iyp1, striped horses of, i. 58; pigs of, i.
66, 67,76 ; breeding of rabbits in, i. 112;
cultivation of pigeons in, i. 205-206.

InDIvipvaL variability in pigeons, i. 158-
160,

INGLEpEW, Mr., cultivation of European
vegetables in India, ii. 169.

“ INDISCHE Taube,” ii, 144.

INHERITANCE, ii. 1-84, 871-373, 395, 397-
402; doubts entertained of by some
writers, ii. 3; importance of to breeders,
3-4 ; evidence of, derived from statistics
of chances, 5 ; of peculiarities in man, 5-
7, 12-16 ; of disease, 7-8, 17 ; of peculia-
rities in the eye, 8-10; of deviations
from symmetry, 12; of polydactylism,
12-16; capriciousness of, 17-22, 27;
of mutilations, 22-24; of congenital
monstrosities, 24; causes of absence of,
24-26; by reversion or atavism, 28-61;
its connexion with fixedness of charac-
ter, 62-64; affected by prepotency of
transmission of character, 65-71; limited
by sex, 71-75; at corresponding pe-
riods of life, 75-80; summary of the
subject of, 80-84; laws of, the same in
seminal and bud varieties, i, 409; of
characters in the horse, i. 10-11; in
cattle, i. 87; in rabbits, i. 107; in the
peach, i. 339; in the nectarine, i. 340;
in plums, i. 847; in apples, i. 350; in
pears, i, 851; in the pansy, i. 369; of
primary characters of Columba livia in
crossed pigeons,i. 201; of peculiarities of
plumage in pigeons, i. 160-161; of pecu-
liarities of foliage in trees, i. 362; effects
of, in varieties of the cabbage, i, 325.

INSANITY, inheritance of, ii. 7, 78. a

Insects, regeneration of lost parts in, 11.
15, 294; agency of, in fecundation of
larkspurs, ii. 21; effect of changed con-
ditions upon, ii. 157; sterile neuter, i.

INSTINCTS.

186-187; monstrosities in, ii. 269,

aes)

Instincts, defective, of silkworms, i. 304.

INTERBREEDING, Close, ill effects of, ii. 114-
131, 175.

InTERCROSSING, of species, as a cause of
variation, i. 188; natural, of plants, i.
336; of species of Canide and breeds of
dogs, i. 31-33; of domestic and wild
cats, i. 44-45 ; of breeds of pigs, i. 71,
78; of cattle, i. 83; of varieties of cab-
bage, i. 324; of peas, i. 326, 829-330;
of varieties of orange, i. 336; of species
of strawberries, i. 351-352; of Cucur-
bite, i. 357-358 ; of flowering plants, i.
364; of pansies, i. 368.

INTERDIGITAL pits, in goats, i. 102.

INTERMARRIAGES, Close, ii. 122-123.

Inrestings, elongation of, in pigs, i. 73;
relative measurements of parts of, in
goats, i. 102; effects of changed diet
on, ii. 302.

Ipomea purpurea, ii. 128.

TRELAND, remains of Bos frontosus and
longifrons found in, i. 81.

Iris, hereditary absence of. the, ii. 9;
hereditary peculiarities of colour of the,
ii, 9-10.

Irisu, ancient, selection practised by the,
ii. 203.

Tron period, in Europe, dog of, i. 18.

ISLANDS, oceanic, scarcity of useful plants
on, wool.

IsLay, pigeons of, i. 183.

IsonaTion, effect of, in favour of selection,
li, 233-234.

IvaLy, vine growing
bronze period, i. 332,

Ivy, sterility of, in the north of Europe,
ii. 170.

in, during the

Jack, Mr., effect of foreign pollen on
grapes, 1. 400.

JACKAL, i. 24, 27, 30; hybrids of, with
the dog, i. 32; prepotency of, over the
dog, ii. 67.

J ACOBIN pigeon, i. 154, 208.

ra origin eee: on the mulberry,
i: ;

JAGuAR, with crooked legs, i. 17,

Jamatoa, feral dogs of, i. 28; feral pigs
of, i. 77; feral rabbits of, i. 112,

JAPAN, horses of, i. 53.

JAPANESE pig (figured), i. 69.

JARDINE, Sir W., crossing of domestic and
wild cats, i. 44.

Jarves, J., silkworm in the Sandwich
islands, i. 301.

Java, Fantail pigeon in, i. 148,

JAVANESE ponies, i. 53, 59.

JemMy Burton, i. 309.

Junyns, L., whiteness of ganders, i, 288 ;

INDEX.

KIDNEY. 459

sunfish-like variety of the goldfish, i.
297.

JERDON, J. C., number of eggs laid by the
pea-hen, ii. 112; origin of domestic
fowl, i. 237.

JERSEY, arborescent cabbages of, i. 323.

JESSAMINE, i. 394.

JEITTELES, Hungarian sheep-dogs, i. 24;
crossing of domestic and wild cats, i. 44.

Joun, King, importation of stallions from
Flanders by, ii. 203.

Jounson, D., occurrence of stripes on
young wild pigs in India, i. 76.

JorDAN, A., on Vibert’s experiments on
the vine, i. 332; origin of varieties of
the apple, i. 350; varieties of pears
found wild in woods, ii. 260.

JOURDAN, parthenogenesis in the silk-
moth, ii. 364.

JUAN DE Nova, wild dogs on, i. 27.

JUAN FERNANDEZ, dumb dogs on, i. 27.

Juglans regia, i. 356-357.

Jukes, Prof., origin of the Newfoundland
dog, i. 42.

JULIEN, Stanislas, early domestication of
pigs in China, i. 68; antiquity of the
domestication of the silk-worm in
China, i. 300.

JUMPERS, a breed of fowls, i. 230.

JUNIPER, variations of the, i. 361, 364.

Juniperus suecica, i. 361.

Jussixa grandiflora, ii. 170.

Jussizu, A. de, structure of the pappus in
Carthamus, ii. 316.

Kar, Scotch, reversion in, ii. 32.

“ KALA-PAR”’ pigeon, i. 142.

KA gs, i. 323.

Kaum, P., on maize, i. 322, ii. 307; in-
troduction of wheat into Canada, i.
315; sterility of trees growing in
marshes and dense woods, ii. 170.

“Katmi Lotan,” tumbler pigeon, i. 151.

Kane, Dr., on Esquimaux dogs, i. 21.

KARAKOOL sheep, i. 98.

KARKEEK, on inheritance in the horse,
ii. 10.

“ KARMELITEN Taube,” i. 156.

Karsten on Pulex penetrans, ii. 275.

Karrywak horses, i. 58.

Krevry, R., pelorism in Galeobdolon
luteum, ii. 59.

KeErvner on the culture of Alpine plants,
ii. 163.

Kesrrex, breeding in captivity, ii. 154.

“ KHANDESI,” i. 141.

Kuanc-n1, selection of a variety of rice
by, ii. 205.

KIana, ii. 43.

Kipp, on the canary bird, i. 77, ii. 275.

Kipney Bean, i. 371; varieties of, ii.
256, 275.

I hy fo ae

460

KIDNEYS.

INDEX.

LAXTON,

Kripneys, compensatory development of
the, ii. 300; fusion of the, ii. 841;
shape of, in birds, influenced by the
form of the pelvis, ii. 344.

Kine, Col., domestication of rock doves
from the Orkneys, i. 184, 185.

Kine, P. 8., on the Dingo, i. 21, 28,

Kirsy and Spence, on the growth of
galls, ii. 283.

KrirGuistan sheep, i. 98.

Kurz, breeding in captivity, ii. 154.

KLEINE, variability of bees, i. 298.

Kwieur, Andrew, on crossing horses of
different breeds, i. 51; crossing varie-
ties of peas, i. 326, ii. 129; persistency
of varieties of peas, i. 829; origin of
the peach, i. 338; hybridisation of the
morello by the Elton cherry, i. 347; on
seedling cherries, ibid. ; variety of the
apple not attacked by coccus, i. 349;
intercrossing of strawberries, i, 351,
302; broad variety of the cock’s comb,
i. 365; bud variation in the cherry and
plum, i. 875; crossing of white and
purple grapes, i. 393; experiments in
crossing apples, i. 402, ii. 129; heredi-
tary disease in plants, ii. 11; on inter-
breeding, ii, 116; crossed varieties of
wheat, ii. 130; necessity of intercross-
ing in plants, ii. 175; on variation, ii.
256, 257; effects of grafting, i. 387, ii.
278; bud-variation in a plum, ii. 289;
compulsory flowering of early potatoes,
li. 343; correlated variation of head
and limbs, ii. 823,

Kyox, Mr., breeding of the eagle owl in
captivity, ii, 154.

Kocu, degeneracy in the turnip, i. 325.

Kou.raBt, i. 323.

KOLREUTER, reversion in hybrids, i. 892,
li. 36; acquired sterility of crossed
varieties of plants, i. 358, ii. 101; ab-
sorption of Mirabilis vulgaris by M.
longiflora, ii. 88; crosses of species of
Verbascum, ii. 93, 107; on the holly-
hock, ii. 107; crossing varieties of
tobacco, ii. 108; benefits of crossing
plants, ii, 130, 131, 175-176; self-
impotence in Verbascum, ii. 136, 141;
efiects of conditions of growth upon
fertility in Mirabilis, ii. 164; great de-
velopment of tubers in hybrid plants,
ii. 172; inheritance of plasticity, ii,
241; variability of hybrids of Mira. |
bilis, ii. 265; repeated crossing a cause
of variation, ii. 267-268 ; number of
pollen-graings necessary for fertilization,
li. 363,

““ KRAUSESCHWEIN,” i. 67,

Krony, on the double reproduction of
Meduse, ii. 384.

‘ Kropr-TavBen,” i. 137.

Laat, on the tusks of feral boars in the
West Indies, i. 77; on French wheat
grown in the West Indies, ii. 307; on
the culture of the vine in the West
Indies, ii. 308,

Lapurnem, Adam’s, see Cytisus Adami;
oak-leaved, reversion of, 1. 882 ; pelorism
in the, ii. 346; Waterer’s, i. 390.

LacuMANN, on gemmation and fission, ii.
358,

Lachnanthes tinctoria, ii. 227, 336,

Lacration, imperfect, hereditary, ii. 8;
deficient, of wild animals in captivity,
ii. 158.

Lapronz islands, cattle of, i. 86.

Latnc. Mr., resemblance of Norwegian
and Devonshire cattle, i, 82.

LAKE-DWELLINGS, sheep of, i. 94, ii, 427:
cattle of, ii. 427; absence of the fowl
in, i. 246; cultivated plants of, i. 809,
il. 427, 429; cereals of, i. 317-319;
peas found in, i. 326; beans found in, i.
330.

LaMarE-PiQtort, observations on half-bred
North American wolves, i. 22,

Lampert, A. B., on Thuja pendula or
Jilijormis, i. 862.

LAMBERT family, ii. 4, 76.

LAMBERTYE on strawberries, i. 351, 352;
five-leaved variety of Fragaria collina,
i. 353.

Lanpt, L., on sheep in the Faroe islands,
ii. 103.

La Puata, wild dogs of, i. 27; feral cat
from, i. 47. :

Larcu, ii. 310.

Larksrurs, insect agency necessary for
the full fecundation of, ii, 21,

Larus argentatus, ii. 157.

Larus tridactylus, ii. 302.

Lasreryr, merino shcep in different
countries, i. 99,

Latent characters, ii. 51-56,

LatuaM, on the fowl not breeding in the
extreme north, ii. 161.

Lathyrus, ii. 88,

Lathyrus aphaca, ii. 348. ’

Lathyrus odoratus, ii. 20, 91, 98, 31], 393.

La 'Toucus, J. D., on a Canadian apple
with dimidiate fruit, i, 392-393.

“ Latz-TAvBE,” i. 154.

Latcuer pigeon, i. 155, 207.

Laurus sassafras, ii. 274.

Lawrence, J., production of # new breed
of fox-hounds, i. 40; occurrence of
canines in mares, i. 50; on three-parts-

- bred horses, i. 54; on inheritance in
the horse, ii, 10-11. ;

Lawson, Mr., varieties of the potato, i.
330. ;

Laxton, Mr., bud-variation in _ the
gooseberry, i. 876; crossing of varieties

LAYARD.

INDEX.

LINOTA. 461

of the pea, i. 397-398; double-flowered
_peas, li. 168.

Layarp, EH. L., resemblance of a Caffre
dog to the Esquimaux breed, i. 25, ii.
286; crossing of the domestic cat with
Felis Caffra, i. 44; feral pigeons in
Ascension, i. 190; domestic pigeons of
Ceylon, i. 206; on Gallus Stanleyi, i.
234; on black-skinned Ceylonese fowls,
i. 256.

Le Compre family, blindness inherited in,
ii. 78.

Lrcog, bud-variation in Mirabilis ja-
lapa, i. 382; hybrids of Mirabilis, i.
393, li. 169, 265; crossing in plants, il.
127; fecundation of Passiflora, ii. 137;
hybrid Gladiolus, ii. 139; sterility of
Ranunculus ficaria, ii. 170; villosity in
plants, ii. 277; double asters, ii. 316.

Le Covrrur, J., varieties of wheat, i.
313-315; acclimatisation of exotic wheat
in Kurope, i. 315; adaptation of wheat
to soil and climate, i. 316; selection of
seed-corn, i. 318; on change of soil, ii.
147; selection of wheat, ii. 200; natural
selection in wheat, ii. 233; cattle of
Jersey, li, 234.

Lepcer, Mr., on the Llama and Alpaca,
ii. 208.

Les, Mr., his early culture of the pansy,
i. 368,

Leersia oryzoides, ii. 91.

Lerovur, period of gestation in cattle, i.
87.

Leas, of fowls, effects of disuse on, i. 270-
272; characters and variations of, in
ducks, i. 284-288; fusion of, ii. 341.

Lucuat, cattle of the Cape of Good Hope,
i. 88.

LEHMANN, occurrence of wild double-
flowered plants near a hot spring, ii.
168.

Lutcuroy, W. A., propagation of a weep-
ing yew by seed, ii. 19.

Lerrner, effects of the removal of anthers,
ii. 167.

Lemmine, ii. 152.

Lemons, variegated Symphytum and
Phlox, i. 384.

Lemon, i. 334, 335; orange fecundated by
pollen of the, i. 399.

Lemurs, hybrid, ii. 153.

LEPORIDES, il. 98-99, 152.

Lepstvs, figures of ancient Egyptian dogs,
i. 17; domestication of pigeons in an-
cient Egypt, i. 204.

Leptotes, ii. 134,

Lepus glacialis, i. 111.

Lepus magellanicus, i. 112.

Lepus nigripes, i. 108.

Lepus tibetanus, i. 111.

Lepus variabilis, i, 111.

LEREBOULLET, double monsters of fishes,
ii. 340,

Lesiiz, on Scotch wild cattle, i. 85.

Lesson, on Lepus magellanicus, i. 112.

Leuckart on the larva of Cecidomyide
ii. 360.

Lewis, G., cattle of the West Indies, ii.
229.

Luersetre and Quatrefages, on the
horses of Circassia, ii. 102, 225.

Ligsia, differences in human blood, ac-
cording to complexion, ii. 276,

LIEBREICH, occurrence of pigmentary re-
tinitis in deaf-mutes, ii. 328,

Licuens, sterility in, ii. 171.

LICHTENSTEIN, resemblance of Bosjes-
man’s dogs to Canis mesomelas, i. 25:
Newfoundland dog at the Cape of Good
Hope, i. 36.

Linacs, ii. 164.

LILtace®, contabescence in, ii. 165.

Lilium candidum, ii. 137.

Limes, regeneration of, ii. 376-377.

Lips and head, correlated variation of, ii.
323.

Lime, effect of, upon shells of the mol-
lusea, ii. 280.

Lime tree, changes of by age, i. 364, 387.

Limrration, sexual, ii. 71-75.

LIMITATION, supposed, of variation, ii.
416.

Linaria, pelorism in, ii. 58, 61, 346; pe-
loric, crossed with the normal form, ii.
70; sterility of, ii, 166.

Linaria vulgaris and purpurea, hybrids
of, ii. 94.

Linpuey, John, classification of varieties
of cabbages, i. 324; origin of the peach,
i, 338; influence of soil on peaches and
nectarines, i, 340; varieties of the peach
and nectarine, i. 343; on the New
Town pippin, i. 349; freedom of the
Winter Majetin apple from coccus, i.
349; production of monoecious Haut-
bois strawberries by bud-selection, i.
303; origin of the large tawny necta-
rine, i. 375; bud-variation in the goose-
berry, i. 376; hereditary disease in
plants, ii. 11; on double flowers, ii.
167; seeding of ordinarily seedless
fruits, ii. 168; sterility of Acorus cala-
mus, ii. 170; resistance of individual
plants to cold, ii. 309.

Linnmus, summer and winter wheat re-
garded as distinct species by, i. 315;
on the single-leaved strawberry, 1. 353 ;
sterility of Alpine plants in gardens, ii.
163; recognition of individual reindeer
by the Laplanders, ii. 251; growth of
tobacco in Sweden, ii. 307.

LINNET, ii. 158.

Linota cannabina, ii. 158.

462

LINUM.

INDEX,

LUIZET.

Linum, ii. 165.

Lion, fertility of, in captivity, ii, 150,
151.

Lipart, feral rabbits of, i. 113.

LivinestoneE, Dr., striped young pigs on
the Zambesi, i. 77; domestic rabbits at
Loanda, i. 112; use of grass-seeds as
food in Africa, i. 308; planting of fruit-
trees by the Batokas, i. 309; character
of half-castes, ii. 46; taming of animals
among the Barotse, ii. 160; selection
practised in South Africa, ii, 207, 209.

LivinestTone, Mr., disuse a cause of droop-
ing ears, ii. 301. splat

Lizarps, reproduction of tail in, ii. 294;
with a double tail, ii. 341.

Luama, selection of, ii. 208.

Luoyp, Mr., taming of the wolf, i. 26;
English dogs in northern Europe, i. 36 ;
fertility of the goose increased by do-
mestication, i. 288; number of eges
laid by the wild goose, ii. 112; breed-
ing of the capercailzie in captivity, ii.
156.

Loanpa, domestic rabbits at, i. 112.

Loasa, hybrid of two species of, ii. 98.

Lobelia, reversion in hybrids of, ii. 392;
contabescence in, ii. 166.

Lobelia fulgens, cardinalis, and syphili-
tica, li. 186.

Locxuart, Dr., on Chinese pigeons, i.
206.

Locust-TREE, ii. 274.

LoIsELEUR-DESLONGCHAMPS, originals of
cultivated plants, i. 307; Mongolian
varieties of wheat, i. 313; characters
of the ear in wheat, i. 314; acclimatisa-
tion of exotic wheat in Europe, i. 315;
effect of change of climate on wheat, i.
316; on the supposed necessity of the
coincident variation of weeds and cul-
tivated plants, i. 317; advantage of
change of soil to plants, ii. 146.

Lolium temulentum, variable presence of
barbs in, i. 314.

LoNnG-TAILED sheep, i. 94, 95.

Loocuoo islands, horses of, i. 53.

Lorp, J. K., on Canis latrans, i. 22.

“ LorI RAJAH,” how produced, ii. 280.

Lorius garrulus, ii. 280.

“ Loran,” tumbler pigeon, i. 150.

Loupon, J. W., varieties of the carrot, i, —

326; short duration of varieties of peas,
i. 329; on the glands of peach-leaves, i.

343; presence of bloom on Russian |

apples, i. 8349; origin of varieties of the
apple, i. 350; varieties of the goose-
berry, i. 354; on the nut tree, i. 357;
varieties of the ash, i. 360; fastigate
juniper (J. suecica), i. 361; on Ilex
aquifolium ferox, i. 362; varieties of
the Scotch fir, i. 363; varieties of the

hawthorn, ibid.; variation in the per-
sistency of leaves on the elm and Turk-
ish oak, i. 363; importance of culti-
vated varieties, ibid.; varieties of Rosa
spinosissima, i. 367; variation of dah-
lias from the same seed, i. 370; pro-
duction of Provence roses from seeds of
the moss rose, i. 8380; effect of grafting
the purple-leaved upon the common
hazel, i. 395; nearly evergreen Cornish
variety of the elm, ii, 310.

Low, G., on the pigs of the Orkney
islands, i. 70.

Low, Prof., pedigrees of greyhounds, ii. 3;
origin of the dog, i. 10; burrowing in-
stinct of a half-bred Dingo, i. 28;
inheritance of qualities in horses, i.
51; comparative powers of English
race-horses, Arabs, &c., i. 54; British
breeds of cattle,“i. 80; wild cattle of
Chartley, i. 84; effect of abundance
of food on the size of cattle, i. 91; effects
of climate on the skin of cattle, i. 92, ii.
326; on interbreeding, ii. 116; selec-
tion in Hereford cattle, ii. 214; forma-
tion of new breeds, ii. 244; on “ sheet-
ed” cattle, ii. 349.

Lowg, Mr., on hive bees, i. 299.

Lows, Rev. Mr., on the range of Pyrus
malus and P. acerba, i. 348.

“Lowran ” tumbler pigeon, i, 150.

Loxia pyrrhula, ii. 154.

Lussocr, Sir J., developments of the
Hphemeride, ii. 366.

Lweas, P., effects of cross-breeding on the
female, i. 404; hereditary diseases, ii.
7, 78-79; hereditary affections of the
eye, ii. 9-10; inheritance of anomalies
in the human eye and in that of the
horse, ii. 10, 11; inheritance of poly-
dactylism, ii. 18; morbid uniformity in
the same family, ii. 17; inheritance of
mutilations, ii. 23; persistency of cross-
reversion, ii. 835; persistency of charac-
ter in breeds of animals in wild
countries, ii. 64; prepotency of trans-
mission, ii. 65, 68; supposed rules of
transmission in crossing animals, ii. 68 ;
sexual limitations of transmission of
peculiarities, ii. 72-73; absorption of
the minority in crossed races, ii. 88;

, crosses without blending of certain cliar-
acters, ii. 92; on interbreeding, ii. 116;
variability dependent on reproduction,
ii. 250 ; period of action of variability, ii.
260; inheritance of deafness in cats,
ii. 329 ; complexion and constitution, il.
335.

Lucazre-Dutuiers, structure and growth
of galls, ii. 282-284.

Luizet, grafting of a peach-almond on a
peach, i, 338.

LUTKE. INDEX.

LiKe, cats of the Caroline Archipelago,
1,47.

Luxuriance, of vegetative organs, a
cause of sterility in plants, ii. 168-171.

Lyonnet, on the scission of Na?s, ii. 358.

Lysimachia nummularia, sterility of, ii.
170.

Lythrum, trimorphic species of, ii. 400.

Lythrum salicaria, ii. 183; contabescence
in, ii, 166.

Lytta vesicatoria, affecting the kidneys, |

i. 380.

Macacus, species of, bred in captivity, ii.
153.

Macavunay, Lord, improvement of the
English horse, ii. 213.

M‘CLELLAND, Dr., variability of fresh-
water fishes in India, ii. 259.

M‘Coy, Prof., on the dingo, i. 26.

MacraybEN, influence of soil in pro-
ducing sweet or bitter oranges from: the
same seed, i. 335.

MacciLuivray, domestication of the rock-
dove, i. 185; feral pigeons in Scotland,
i. 190; number of vertebree in birds, i.
266; on wild geese, i. 287; number of
eggs of wild and tame ducks, ii. 112.

Mackenzin, Sir G., peculiar variety of the
potato, i. 330.

Mackenzin, P., bud-variation in the cur-
rant, 1. 376.

Mackinnon, Mr., horses of the Falkland
islands, i. 52; feral cattle of the Falk-
land islands, i. 86.

MacKnieut, C., on interbreeding cattle,
ii. 118.

MacNas, Mr., on seedling weeping
birches, ii. 18; non-production of the
weeping beech by seed, ii. 19.

Mapaaascar, cats of, i. 47,

Mavpen,H., on interbreeding cattle, ii.118.

Maovetra, rock pigeon of, i. 184.

Magnolia grandiflora, ii. 308.

Matzu, its unity of origin, i. 320; anti-
quity of, zbid.; with husked grains said
to grow wild, ibid. ; variation of, i. 321 ;
irregularities in the flowers of, i. 321;
persistence of varieties, ibid. : adapta-
tion of to climate, i. 322, ii. 307 ; accli-
matisation of, ii. 313, 347; crossing of,
i. 400, ii, 104-105; extinct Peruvian
varieties of, ii. 425,

Mauay fowl, i. 227.

Matay Archipelago, horses of, i. 53;
short-tailed cats of, 1.47; striped young
wild pigs of, i. 76; ducks of, i, 280.

MALs#, influence of, on the fecundated
female, i. 397-406 ; supposed influence
of, on offspring, ii. 68.

Mate flowers, appearance of, amono
female flowers in maize, i. 321. e

MARTINS. 463

MALFORMATIONS, hereditary, ii. 79.
Malva, fertilisation of, i. 402, ii. 363.
Mamestra suasa, ii. 157.

Mamma, variable in number in the pig, i.
74; rudimentary, occasional full deve-
lopment of, in cows, i. 87, ii. 317; four
present in some sheep, i. 95; variable
in number in rabbits, i. 106: latent
funetions of, in male animals, ii, 52,
317; supernumerary and inguinal, in
women, ii. 57,

Mancues, Mr., annual varieties of the
heartsease, ii. 305.

Mante.t, Mr., taming of birds by the
New Zealanders, ii. 161.

Manu, domestic fowl noticed in the Tn-
stitutes of, i. 246,

Manure, effect of, on the fertility of
plants, ii. 163.

Manx cats, i. 46, ii. 66.

MAakrcet de Serres, fertility of the ostrich,
ii. 156.

MArIANNE islands, varieties of Pandanus
in, li. 256.

Markuay, Gervase, on rabbits, i. 104, ii.
204.

Marxkuor, probably one of the parents of
the goat, i. 101.

Manrquanp, cattle of the Channel Islands,
i. 80,

Marrimpory, inheritance in the horse,
ii. 10.

Marrow, vegetable, i. 357.

Marryatt, Capt., breeding of asses in
Kentucky, ii. 237.

Marspen, notice of Gallus giganteus, i. 235.

Marsuauu, Mr., voluntary selection of
pasture by sheep, i. 96; adaptation of
wheats to soil and climate, i. 316;
“ Dutch-buttocked” cattle, ii. 8; se-
gregation of herds of sheep, ii. 103;
advantage of change of soil to wheat
and potatoes, ii. 146; fashionable
change in the horns of cattle, ii. 210;
sheep in Yorkshire, ii. 235.

MarsHat., Prof., growth of the brain in
microcephalous idiots, ii. 389.

Martens, E. Von, on Achatinella, ii. 53.

Martin, W. ©. L., origin of the dog, i.
16; Egyptian dogs, i. 18; barking of
a Mackenzie River dog, i. 27; African
hounds in the 'Tower menagerie, i. 32 ;
on dun horses and dappled asses, i. 55 ;
breeds of the horse, i. 49; wild horses,
i. 51; Syrian breeds of asses, i. 62 ;
asses without stripes, i. 63; effects of
cross-breeding on the female in dogs,
i. 404; striped legs of mules, ii. 42.

Marrtnsy, defective instincts of silkworms,
i. 304.

Martins, C., fruit trees of Stockholm, ii.
307.

464

MASON.

INDEX.

MOQUIN-TANDON.

Mason, W., bud-variation in the ash, i.
382.

Masters, Dr., reversion in the spiral-
leaved weeping willow, i. 383; on
peloric flowers, ii. 58; pelorism in a
clover, ii. 346; position as a cause of
pelorism, ii. 345, 347.

Masters, Mr., persistence of varieties of
peas, i. 329; reproduction of colour in
hyacinths, ii. 20; on hollyhocks, ii.
107; selection of peas for seed, ii.
199-200; on Opuntia leucotricha, ii.
286; reversion by the terminal pea in
the pod, ii. 347.

Mastirr, sculptured on an Assyrian mo-
nument, i. 17, ii. 429; Tibetan, i. 35-
36, ii. 278.

Marrurws, Patrick, on forest trees, ii.
237.

Matthiola annua, i. 399, ii. 20.

Matthiola incana, i. 881, 399.

Mavucuamp merino sheep, i. 100.

Mavupvuyt, crossing of wolves and dogs in
the Pyrenees, i. 24.

Mavunp, Mr. crossed varieties of wheat, ii.
130.

MAUvPERTUIS, axiom of “least action,”
Lae.

Mauritius, importation of goats into, i.
101.

Maw, G., correlation of contracted leaves
and flowers in pelargoniums, ii. 330,
3el.

Mawz, fertility of Brassica rapa, ii. 165.

Mawillaria, self-fertilised capsules of, ii.
134; number of seeds in, ii. 379.

Mazillaria atro-rubens, fertilisation of, by
M. squalens, ii. 133.

Mayes, M., self-impotence in Amaryllis,
#2185;

Mecxket, on the number of digits, ii. 13;
correlation of abnormal muscles in the
leg and arm, ii. 322.

Mepvusm, development of, ii. 368, 384.

Merenan, Mr., comparison of European
and American trees, ii. 281.

Meleagris mexicana, i. 292.

Meles taxus, ii. 151.

Metons, i. 359-360; mongrel, supposed
to be produced from a twin-seed, i.
391; crossing of varieties of, i. 399, ii,
108, 129; inferiority of, in Roman
times, ii. 216; changes in, by culture
and climate, ii. 275; serpent, correla-
tion of variations in, ii. 8330; analogous
variations in, ii. 349.

MrmBrangs, false, ti. 294-295.

Meéniérries, on the stomach of Strix
grallaria, ii. 302.

Menrneittis, tubercular, inherited, ii. 78.

METAGENESIS, ii. 366.

METAMORPHOSIS, ii. 366.

ag aang and development, ii. 388,

MerzcER, on the supposed species of
wheat, i. 312-313; tendency of wheat
to vary, i. 315; variation of maize, i.
321-322; cultivation of American
maize in Europe, i. 322, ii, 347; on
cabbages, i. 323-325; acclimatisation
of Spanish wheat in Germany, ii. 26;
advantage of change of soil to plants,
ii. 146; on rye, ii. 254; cultivation of
different kinds of wheat, ii. 261,

Mexico, dog from, with tan spots on the
rot i. 29; colours of feral horses in,
6%;

Meyegn, on sending of bananas, ii. 168.

Mice, grey and white, colours of, not
blended by crossing, ii. 92; rejection
of bitter almonds by, ii. 232; naked,
li. 279.

Micwavx, F., roan-coloured feral horses
of Mexico, i. 61; origin of domestic
turkey, i. 292; on raising peaches from
seed, 1. 339.

Micus., F., selection of horses in media-
val times, ii. 203; horses preferred on
account of slight characters, ii. 209.

Micuety, effects of food on caterpillars,
li. 280; on Bombyx hesperus, ii. 304.

MICROPHTHALMIA, associated with defec-
tive teeth, ii. 328.

Mrippens, Danish, remains of dogs in, i.
18, ii. 427.

MIGNONETTE, li. 237, 311.

MILxeEr, i. 371.

Mitts, J., diminished fertility of mares
when first turned out to grass, ii. 161.
Mitne-Epwarps, on the development of

the crustacea, ii. 368.

Minne-Epwarps, A., on a crustacean
with a monstrous eye-peduncle, ii. 391.

Milvus niger, ii. 154.

Mimutlus luteus, ii, 128.

Minor, W. C., gemmation and fission in
the Annelida, ii. 358.

Mirabilis, fertilisation of, ii, 863 ; hybrids
of, ii. 181, 169, 265.

Mirabilis jalapa, i. 382, 393.

Mirabilis longiflora, ii. 88.

Mirabilis vulgaris, ti. 88.

Misocampus and Cecidomyia, i. 5.

MircHett, Dr., effects of the poison of
the rattlesnake, ii. 289. ‘

Mrrrorp, Mr., notice of the breeding of
horses by Erichthonius, ii. 202.

Moccas Court, weeping oak at, ii. 18.

MoerorD, horses poisoned by fool’s par-
sley, ii. 337. ea

MO ter, L., effects of food on insects, 11.
281.

Moavin-Tanpon, original form of maize,
i. 320; variety of the double colum-

MOLE.

INDEX.

465

MUSK,

bine, i. 365; peloric flowers, ii. 58-59,
61; position as a cause of pelorism in
flowers, ii. 345; tendency of peloric
flowers to become irregular, ii. 70; on
monstrosities, 1. 254; correlation in
the axis and appendages of plants, ii.
321; fusion of homologous parts in
plants, ii. 339, 341-342; on a bean
with monstrous stipules and abortive
leaflets, ii. 343; conversion of parts of
flowers, ii. 392.

Mo .z, white, ii. 332.

Mot. and Gayot, on cattle, i. 80, ii. 96,
210.

Mo..usca, change in shells of, ii. 280.

Monkgz, Lady, culture of the pansy by, i.
368.

Monkeys, rarely fertile in captivity, ii.
153.

Monnier, identity of summer and winter
wheat, i. 315.

Monster, cyclopean, ii. 341.

Monsters, double, ii. 339-340.

Monsrrosirizs, occurrence of, in domesti-
cated animals and cultivated plants, i.
366, ii. 254; due to persistence of em-
bryonic conditions, ii. 57; occurring by
reversion, ii. 57-60; a cause of sterility,
ii. 166-167; caused by injury to the
embryo, ii. 269.

MonveeGazza, growth of a cock’s-spur in-
serted into the eye of an ox, ii. 369.
Monteomery, E., formation of cells, ii.

370.

Moor, J. H., deterioration of the horse in
Malasia, i. 53.

Moorcrort, Mr., on Hasora wheat, i. 313;
selection of white-tailed yaks, ii. 206;
melon of Kaschmir, ii. 275: varieties
of the apricot cultivated in Ladakh, i.
345; varieties of the walnut cultivated
in Kaschmir, i. 356.

Moors, Mr., on breeds of pigeons, i. 148,
156, 208, 209, 211.

Moorvk, fertility of, in captivity, ii. 156.

Mortot, dogs of the Danish Middens, i.
18; sheep and horse of the bronze
period, ii. 427,

Mormodes ignea, ii. 58.

Morocco, estimation of pigeons in, i,
205.

Morrey, C., on pelorism, ii. 58: in Cal-
ceolaria, ii. 346; non-coincidence of
double flowers and variegated leaves
ii. 167.

Morris, Mr., breeding of the Kestrel in
captivity, ii. 154.

Morton, Lord, effect of fecundation by a
quagga on an Arab mare, i. 403-404.
Morton, Dr., origin of the dog, i. 16;

hybrid of zebra and mare, ii, 42.

Morus alba, i. 334.

VOL, II.

Moscow, rabbits of, i. 106, 120; effects
of cold on pear-trees at, ii. 307,

Mossss, sterility in, ii. 171 ; retrogressive
metamorphosis in, ii. 361,

Moss-rosx, probable orizin of, from Rosa
centifolia, i. 379 ; Provence roses pro-
duced from seeds of, i. 380,

Mosto, Cada, on the introduction of
rabbits into Porto Santo, i. 113.

Morrure of fruits and flowers, i. 400,

MovrFF oy, i. 94.

MovuntTAIn-Asi, ii. 230.

Mouse, Barbary, ii. 152.

‘“* MOVEN-TAUBE,” i. 148,

Mowsray, Mr., on the eggs of game fowls,
i, 248 ; early pugnacity of game cocks,
i. 251; diminished fecundity of the
pheasant in captivity, ii. 155.

Mowsray, Mr., reciprocal fecundation
of Passiflora alata and racemosa, ii.
137.

Mutarros, character of, ii. 46.

MULBERRY, i. 334, ii. 256.

Mute and hinny, differences in the, ii.
67-68.

Mots, striped colouring of, ii. 42; obsti-
nacy of, ii, 45; production of, among
the Romans, ii. 110; noticed in the
Bible, ii. 202.

Miter, Fritz, reproduction of orchids,
ii, 134-135; development of crustacea,
il. 868; number of seeds in a mazil-
luria, ii. 379.

Miter, H., on the face and teeth in
dogs, i. 34, 73, ii. 345.

Mittin, J., production of imperfect nails
after partial amputation of the fingers,
li. 15; tendency to variation, ii. 252;
atrophy of the optic nerve consequent
on destruction of the eye, ii. 297; on
Janus-like monsters, ii. 340; on gem-
mation and fission, ii. 358; identity of
ovules and buds, ii. 360; special af-
finities of the tissues, ii. 380.

Miuirr, Max, antiquity of agriculture,
ii. 243.

Mutripticrry of origin of pigeons, hypo-
theses of, discussed, i. 188-194.

Monyz, F., on Niata cattle, i. 90.

Munro, R., on the fertilisation of orchids,
ii. 133 ; reproduction of Passiflora alata,
ii. 138.

“ Murassa”’ pigeon, i. 144.

Murrny, J. J., the structure of the eye
not producible by selection, ii, 222.

Mus alexandrinus, ii. 87-88.

Musa sapientum, Chinensis and Caven-
dishti, i. 377.

Muscari comosum, ii. 185, 316.

Muscuxs, effects of use on, ii. 297.

Musk duck, feral hybrid of, with the
common duck, i. 190.

2H

*

466 MUSMON.

INDEX. NIATA.

Muvsmon, female, sometimes hornless, i. 95.

Moriiations, inheritance or non-inherit-
ance of, ii. 22-24, 397.

Myatrr, on a five-leaved variety of the
strawberry, i. 353.

Myoprta, hereditary, ii. 8.

Myrrapopa, regeneration of lost parts in,
ii, 15, 294.

NaILs, growing on stumps of fingers, il.
394.

Nats, scission of, ii. 358.

Namaauas, cattle of the, i. 88, ii. 207.

Narcissus, double, becoming single in poor
soil, ii. 167.

NARVAEZ, on the cultivation of native
plants in Florida, i. 312.

Nasua, sterility of, in captivity, ii. 152.

“Navas,” or Niatas, a South American
breed of cattle, i. 89-91.

Naruusivs, H. von, on the pigs of the
Swiss lake-dwellings, i. 68; on the
races of pigs, i. 65-68; convergence of
character in highly-bred pigs, i. 73, ii.
241; causes of changes in the form of
the pig’s skull, i. 72-73; changes in
breeds of pigs by crossing, i.78; change
of form in the pig, ii. 279; effects of
disuse of parts in the pig, ii. 299;
period of gestation in the pig, i. 74;
appendages to the jaw in pigs, i. 76;
on Sus pliciceps, 1.70; period of gesta-
tion in sheep, i. 97; on Niata cattle, i.
89; on short-horn cattle, ii. 118; on
interbreeding, ti. 116; in the sheep, ii.
120; in pigs, ii, 122; unconscious
selection in cattle and pigs, li. 214;
variability of highly selected races, ii.
238.

Nato, P., on the Bizzaria orange, i. 391.

Narturat selection, its general principles,
i, 2-14.

* Narurr, sense in which the term is
employed, i, 6.

Navpmy, supposed rules of transmission in
crossing plants, ii. 68; on the nature of
hybrids, ii, 48-49; essences of the
species in hybrids, ii. 386, 401 ; rever-
sion of hybrids, ii. 36, 49-50; rever-
sion in flowers by stripes and blotches,
ii. 37; hybrids of Linaria vulgaris and
purpurea, il. 94; pelorism in Linaria,
li. 58, 346; crossing of peloric Linaria
with the normal form, ii. 70; variability
in Datura, ii. 266; hybrids of Datura
levis and stramoniuwm, i. 392; prepo-
tency of transmission of Datura stramo-
nium when crossed, ii. 67; on the pollen
of Mirabilis and of hybrids, i. 889; fer-
tilisation of Mirabilis, ii. 363 ; crossing
of Chamerops humilis and the date palm,
i. 399; cultivated Cucurbitacese, 1. 357-

360, ii. 108; rudimentary tendrils in
gourds, ii. 316; dwarf Cucurbitx, ii.
330; relation between the size and
number of the fruit in Cucurbita pepo,
ii. 343; analogous variation in Cu-
curbitx, ii. 349; acclimatisation of Cu-
curbitaces, ii. 313; production of fruit
by sterile hybrid Cucurbitaces, ii. 172;
on the melon, i. 360, ii. 108, 275; in-
capacity of the cucumber to cross with
other species, i. 359.

NEcTARINE, i. 336-344; derived from the
peach, i. 337, 339-342; hybrids of, i.
339; persistency of characters in seed-
ling, 1. 340; origin of, ibid.; produced
on peach trees, i, 340-341; producing
peaches, i. 341; variation in, i. 342-348;
bud-variation in, i. 374; glands in the
leaves of the, ii. 231; analogous varia-
tion in, ii. 348.

Necrary, variations of, in pansies, i. 369.

Nees, on changes in the odour of
plants, ii. 274.

“ NEGRO” cat, i. 46.

NeGroes, polydactylism in, ii. 14; selee-
tion of cattle practised by, ii. 207.

Neouiruic. period, domestication of Bos
longifrons and primigenius in the, i.
81; cattle of the, distinct from the
original species, i. 87; domestic goat in
the, i. 101; cereals of the, 1. 317.

NERVE, optic, atrophy of the, ii. 297.

NEUMEISTER, on the Dutch and German
pouter pigeons, i. 138; on the Jacobin
pigeon, 1. 154; duplication of the mid-
dle flight feather in pigeons, i. 159; on
a peculiarly coloured breed of pigeons,
“ Staarhalsige Taube,” i. 161; fertility
of hybrid pigeons, i. 192; mongrels of
the trumpeter pigeon, ii. 66; period of
perfect plumage in pigeons, ii. 77;
advantage of crossing pigeons, ii. 126.

Nevratcia, hereditary, ii. 79.

New ZEALAND, feral cats of, i. 47; culti-
vated plants of, i. 311.

NEWFOUNDLAND dog, modification of. in
England, i. 42.

Newmay, E., sterility of Sphingidee under
certain conditions, ii. 158.

Newport, G., non-copulation of Vanessx
in confinement, ii. 157; regeneration of
limbs in myriapoda, li. 294; fertilisa-
tion of the ovule in batrachia, ii.
363.

Newt, polydactylism in the, ii. 14.

Newron, A., absence of sexual distinc-
tions in the Columbide, i. 162; pro-
duction of a “ black-shouldered ” pea-
hen among the ordinary kind, i. 291;
on hybrid ducks, ii. 157.

Neamt, Lake, cattle of, i. 88.

“ Nava” cattle, i i. 89-91; resemblance of

ol

=~

~_—

emi

a

9 Aiea

NICARD. INDEX.

OUISTITI. 467

to Sivatherium, i. 89; prepotency of
transmission of character by, ii. 66.

“ NicarD” rabbit, i. 107.

Nicwoxson, Dr., on the cats of Antigua, i.
46; on the sheep of Antigua, i. 98.

Nicotiana, crossing of varieties and species
of, ii. 108; prepotency of transmission
of characters in species of, ii. 67; con-
tabescence of female organs in, ii. 166.

Nicotiana glutinosa, ii. 108.

Niepsvune, on the heredity of mental cha-
racteristics in some Roman families,
ii. 65,

NIGHT-BLINDNESS, non-reversion to, ii. 36.

Niusson, Prof., on the barking of a young
wolf, i. 27; parentage of European
breeds of cattle, i. 80, 81; on Bos
frontosus in Scania, i. 81.

Nrvp, Mr., on the dingo, i. 39.

* Nisus formativus,” i. 293. 294, 355.

Nirzscu, on the absence of the oil-gland
in certain Columbe, i. 147.

NON-INHERITANCE, causes of, ii, 24-26,

“ NonNAIN” pigeon, i. 154.

NorpMann, dogs of Awhasie, i. 25.

Normanby, pigs of, with appendages
under the jaw, i. 75.

Norway, striped ponies of, i. 58.

Norr and Gliddon, on the origin of the
dog, i. 16; mastiff represented on an
Assyrian tomb, i. 17; on Egyptian
dogs, i.18; on the Hare-Indian dog,
i, 22.

Notylia, ii. 135.

NovRISHMENT, excess of, a cause of vari-
ability, ii. 257.

Noumper, importance of, in selection, ii.
235,

Numida ptilorhyncha, the original of the
Guinea-fowl, i. 294.

Nun pigeon, i. 155; known to Aldrovandi,
i. 207.

Nurmec tree, ii. 237.

Oak, weeping, i. 361, ii. 18, 241; pyra-
midal, i. 361; Hessian, i. 361; late-
leaved, i. 363; variation in persistency
of leaves of, i. 8363; valueless as timber
at the Cape of Good Hope, ii. 274;
changes in, dependent on age, i. 887;
galls of the, ii. 282.

Oats, wild, i. 313; in the Swiss lake-
dwellings, i. 319.

OBERLIN, change of soil beneficial to the
potato, ii. 146.

Opart, Count, varieties of the vine, i.
333, il. 278; bud-variation in the vine,
i; At:

Opour and colour, correlation of, ii, ape

Ccidium, ii. 284.

CGnothera biennis, bud- variation in, i,
382.

Oat, W., resemblance of twins, ii, 252,

OIL-GLAND, absence of, in fantail pigeons,
i. 147, 160.

OtprieLp, Mr., estimation of European
dogs among the natives of Australia,
li. 215,

OLEANDER, stock affected by grafting in
the, i. 394,

Ouier, Dr., insertion of the periosteum
of a dog beneath the skin of a rabbit,
ii. 369.

Oncidium, reproduction of, ii, 133-1 35,
164.

Onrons, crossing of, ii. 90; white, liable
to the attacks of fungi and disease, ii.
228, 336.

Ophrys apifera, self - fertilisation of, ii.
91; formation of pollen by a petal in,
li, 392,

Opuntia leucotricha, ii. 277.

ORANGE, i. 334-336; crossing of, ii. 91;
with the lemon, i. 399, ii. 365; natu-
ralisation of, in Italy, ii. 308 ; variation
of, in North Italy, ii. 256; peculiar
variety of, ii. 331; Bizzaria, i. 391;
trifacial, ¢bid.

Orcuins, reproduction of, i. 402, 403; ii.
133-135.

OrrorD, Lord, crossing greyhounds with
the bulldog, i. 41.

ORGANISMS, origin of, i. 13.

ORGANISATION, advancement in, i. 8.

OrGans, rudimentary and aborted, ii,
315-318 ; multiplication of abnormal,
li. 391,

ORIOLE, assumption of hen-plumage by a
male in confinement, ii. 158.

Orkney islands, pigs of, i. 70; pigeons of,
i. 184.

OrTHopTERA, regeneration of hind legs in
the, ii. 294.

Orthosia munda, ii. 157.

Orton, R., on the effects of cross-breeding
on the female, i. 404; on the Manx
cat, ii. 66; on mongrels from the silk-
fowl, ii. 67.

Ossorne, Dr., inherited mottling of the
iris, ii. 10.

OsprEY, preying on Black-fowls, ii. 230.

OsTEN-SACKEN, Baron, on American oak
galls, ii. 282.

OsTEoLoGicaL characters of pigs, i. 66,
67, 71-74; of rabbits, i. 115-130; of
pigeons, i. 162-167; of ducks, i. 282-
284.

Osrricu, diminished fertility of the, in
captivity, ii. 156.

Osryaxs, selection of dogs by the, ii. 206.

Orrer, ii. 151.

‘“Orrrr” sheep of Massachusetts, i. 100.

Oups, feral humped cattle in, i. 79.

Ovistrri, breed in Europe, ii. 153.

a 2

.

468

OVARY,

INDEX.

PATAGONIAN.

Ovary, variation of, in Oucurbita mos-
chata, i. 359; development of, inde-
pendently of pollen, i. 403.

Ovis montana, i. 99.

Ovuxs and buds, identity of nature of, ii.
360.

Owen, Capt., on stiff-haired cats at Mom-
bas, i. 46,

Owen, Prof. R., paleontological evidence
as to the origin of dogs, i. 15; on the
skull of the “ Niata” cattle, i. 89, 90;
on fossil remains of rabbits, i. 104; on
the significance of the brain, i, 124 ; on
the number of digits in the Ichthyo-
pterygia, ii, 16 ; on metagenesis, ii. 366; |
theory of reproduction and partheno- |
genesis, ii. 375.

OWL, eagle, breeding in captivity, ii. 154.

Ow1 pigeon, i. 148; African, figured, i.
149; known in 1735, i. 209.

Ozxalis, trimorphic species of, ii. 400.

Oxalis rosea, ii. 132.

Ox ey, Mr., on the nutmeg tree, ii, 237.

Oysters, differences in the shells of, ii.
280.

Paca, sterility of the, in confinement, ii.
152.

Pactric islands, pigs of the, i. 70.

Paoua, earliest known flower garden at,
li. 217.

Pavvan fowl of Aldrovandi, i. 247.

Pzonia moutan, ii. 205.

Pony, tree, ancient cultivation of, in
China, ii. 205. |

Pampas, feral cattle on the, i. 85.

Pandanus, ii. 255.

PaNnGENEsIs, hypothesis of, ii. 357-404.

Panicum, seeds of, used as food, i. 309;
found in the Swiss lake-dwellings, i.
317.

Pansy, i. 368-370.

Pappvs, abortion of the, in Carthamus, ii.
316.

Pacet, on the Hungarian sheep dog, i.
24,

Pacet, inheritance of cancer, ii. 7;
hereditary elongation of hairs in the
eyebrow, ii. 8; period of inheritance of
cancer, li. 79-80; on Hydra, ii. 293 ;
on the healing of wounds, ii. 294; on
the reparation of bones, ibid.; growth
of hair near inflamed surfaces or
fractures, ii. 295; on false membranes,
ibid. ; compensatory development of the
kidney, ii. 300; bronzed skin in disease
of supra-renal capsules, ii. 331; unity
of growth and gemmation, ii. 359;

‘independence of the elements of the
body, ii. 369; affinity of the tissues for
Special organic substances, ii. 380.

Pa.xas, on the influence of domestica- |

tion upon the sterility of intercrossed
species, i. 31, 83, 193, ii. 109; hypo-
thesis that variability is wholly due to
crossing, i. 188, 374, ii. 250, 264; on
the origin of the dog, i. 16; variation
in dogs, i. 33; crossing of dog and
jackal, i. 25; origin of domestic cats, i.
43; origin of Angora cat, i. 45; on
wild horses, i. 52, 60; on Persian sheep,
i. 94; on Siberian fat-tailed sheep, li.
279; on Chinese sheep, ii. 315; on
Crimean varieties of the vine, i. 333;
on a grape with rudimentary seeds, ii.
316; on feral musk-ducks, ii. 46;
sterility of Alpine plants in gardens, ii.
163; selection of white-tailed yaks, ii.
206.

Paradoxurus, sterility
captivity, ii. 151.
Paracauay, cats of, i. 46; cattle of, i. 89;
horses of, ii. 102; dogs of, ii, 102;
black-skinned domestic fowl of, i.

232.

PARALLEL variation, ii. 848-352.

PaRAmMos, woolly pigs of, i. 78.

Parasites, liability to attacks of, de-
pendent on colour, ii. 228.

PariaH dog, with crooked legs, i. 17; re-
sembling the Indian wolf, i. 24.

PaRIsET, inheritance of handwriting, ii. 6.

Parker, W. K., number of vertebre in
fowls, i. 266.

Parkinson, Mr., varieties of the hyacinth,
i. 370.

Parkyns, Mansfield, on Columba guinea,
i, 183.

PARMENTIER, differences in the nidifi-
cation of pigeons, i. 178; on white
pigeons, ii, 230.

Parrots, general sterility of, in confine-
ment, il. 155; alteration of plumage of,
ii. 280.

Parsnip, reversion in, ii. 31; influence of
selection on, ii. 201; experiments on,
ii. 277 ; wild, enlargement of roots of,
by cultivation, i. 326.

PARTHENOGENESIS, ii, 359, 364.

PaRTRIDGE, sterility of, in captivity, ii.
156,

Parturition, difficult, hereditary, ii. 8.

Parus major, ii. 231.

Passiflora, self-impotence in species of,
ii. 137-138; contabescence of female
organs in, ii. 166.

Passiflora alata, fertility of, when grafted,
ii. 188.

Pasture and climate, adaptation of breeds
of sheep to, i. 96, 97. ‘ :
Pastrana, Julia, peculiarities in the hair

and teeth of, ii. 328. _ es

ParacontA, crania of pigs from, 1. 77.

PATAGONIAN rabbit, i. 105.

of species of, in

Ye

vt

PATERSON.

INDEX.

PHALANGES, 469

Paterson, R., on the Arrindy silk-moth,
ii. 306.

Paut, W., on the hyacinth, i. 370;
varieties of pelargoniums, i. 378; im-
provement of pelargoniums, ii. 216,

Pavo cristatus and muticus, hybrids of, i.
290.

Pavo nigripennis, i, 290-291.

“ PAVODOTTEN-TAUBE,” i. 141.

PEACH, i. 336-344; derived from the
almond, i. 337; stones of, figured, ibid. ;
contrasted with almonds, i. 338; double-
flowering, i. 338-339 343; hybrids of,
i. 339; persistency of races of, cbid.;
trees producing nectarines, i. 340-341;
variation in, i. 342-343, ii. 256; bud-
variation in, i. 374; pendulous, ii. 18;
variation by selection in, ii, 218; pecu-
liar disease of the, ii. 228; glands on
the leaves of the, ii. 231; antiquity of
the, ii, 308; increased hardiness of the,
ibid.; varieties of, adapted for forcing,
ii. 310; yellow-fleshed, liable to certain
diseases, ii. 336.

PEACH-ALMOND, i. 338.

PEAFOWL, origin of, i. 290; japanned or
black-shouldered, i. 290-291; feral, in
Jamaica. i. 190; comparative fertility
of, in wild and tame states, ii. 112, 268;
white, ii. 332.

Pears, i. 350; bud-variation in, i. 376;
reversion in seedling, ii. 31 ; inferiority
of, in Pliny’s time, ii. 215; winter
nelis, attacked by aphides, ii. 231; soft-
barked varieties of, attacked by wood-
boring beetles, ii. 231; origination of
good varieties of, in woods, ii. 260; Fo-
relle, resistance of, to frost, ii. 306.

Puas, i. 326-330; origin of, 326; varieties
of, 326-329, found in Swiss lake-dwell-
ings, i. 317, 319, 326-329; fruit and
seeds figured, i, 328: persistency of
varieties, i. 329 : intercrossing of varie-
ties, i. 330, 397, ii. 129; effect of
crossing on the. female organs in, i.
398 ; double-fiowered, ii. 168 ; maturity
of, accelerated by selection, ii. 201;
varieties of, produced by selection, ii.
218; thin-shelled, liable to the attacks
of birds, ii. 231; reversion of, by the
terminal seed in the pod, ii. 347.

Bean breeding of the, in captivity, ii.

50.

PEDIGREES of horses, cattle, greyhounds,
game-cocks, and pigs, ii. 3.

Pua, cats of, i. 47; horses of, i. 53,

PELARGONIUMS, multiple origin of, i. 364 .
zones of, i. 366; bud-variation Wel
378 ; variegation in, accompanied by
dwarfing, i. 384; pelorism in, ii, 167,
345 ; by reversion, ii. 59; advantage of
change of soil to, ii, 147; improvement

of, by selection, ii. 216; scorching of,
ii. 229; numbers of, raised from seed, ii.
235; effects of conditions of life on, ii.
274; stove-variety of, ii. 311; correla-
tion of contracted leaves and flowers in,
ii, 580-331.

Pelargonium fulgidum, conditions of fer-
tility in, ii. 164.

“ PELONES,” a Columbian breed of cattle,
i, 88.

Petoric flowers, tendency of, to acquire
the normal form, ii. 70; fertility or
sterility of, ii. 166-167.

Prtorrio races of Gloxinia speciosa and
Antirrhinum majus, i. 365.

PELORISM, ii. 58-60, 345-346.

Petvis, characters of, in rabbits, i. 122-
123; in pigeons, i. 166; in fowls, i. 268;
in ducks, i. 28+,

PEMBROKE Cattle, i. 81.

PENDULOUS trees, i. 361, ii. 348: uncer-
tainty of transmission of, ii. 18-19.

Prn@uIN ducks, i. 280, 282; hybrid of the,
with the Egyptian goose, i. 282.

PENNANT, production of wolf-like curs at
Fochabers, i. 37; on the Duke of
Queensberry’s wild cattle, i. 84.

Pennisetum, seeds of, used as food in the
Punjab, i. 309.

Pennisetum distichum, seeds of, used as
food in Central Africa, i. 808.

Prrcivat, Mr., on inheritance in horses,
il. 10; on horn-like processes in horses,
i. 50.

Perdix rubra, occasional fertility of, in
captivity, ii. 156.

Prriop of action of causes of variability,
ii. 269. f

Periostevm of a dog, producing bone in
a rabbit, ii. 369.

PERIWINELE, sterility of, in England, ii.
170.

Persia, estimation of pigeons in, i. 205;
carrier pigeon of, i, 141; tumbler
pigeon of, i. 150; cats of, i. 45-47;
sheep of, i, 94.

Persica intermedia, i. 338.

PERSISTENCE of colour in horses, i. 50; of
generic peculiarities, i. 111.

Perv, antiquity of maize in, i. 320; _pecu-
liar potato from, i. 331; selection of
wild animals practised by the Incas of,
li. 207-208.

“ PERUCKEN-TAUBE,” i. 154.

PrTALs, rudimentary, in cultivated plants,
ii. 316; producing pollen, ii. 392.

Perunias, multiple origin of, i. 364;
double-flowered, ii. 167.

“ PFAUEN-TAUBE,” i, 146.

Phacocherus Africanus, i. 76.

Phalznopsis, pelorism in, ii. 346.

PHALANGES, deficiency of, ii. 73.

470

PHAPS,

INDEX.

PIGS.

Phaps chalcoptera, ii. 349.

Phaseolus multiflorus, ii. 309, 322.

Phaseolus vulgaris, ii. 309.

Phasianus pictus, i. 275.

Phasianus Amherstiz, i. 275.

PHEASANT, assumption of male plumage
by the hen, ii. 51; wildness of hybrids
of, with the common fowl, ii. 45; pre-
potency of the, over the fowl, ii. 68;
diminished fecundity of the, in cap-
tivity, li. 155.

Pueasants, golden and Lady Amherst’s,
EB! yh

PHEASANT-FOWLS, i. 244,

PHILIPEAUX, regeneration of limbs in the
salamander, ii. 376.

Puiurerar, on the varieties of wheat, i.
314.

PHILIPPINE Islands, named breeds of
game fowl in the,‘i. 232.

Puitures, Mr., on bud-variation in the
potato, i. 385.

Phlox, bud-variation by suckers in, i. 384.

Puruisis, affection of the fingers in, ii.
332.

PickerinG, Mr., on the grunting voice
of humped cattle, i. 79; occurrence of
the head of a fowl in an ancient
Egyptian procession, i. 246 ; seeding of
ordinarily seedless fruits, ii. 168; ex-
tinction of aycient Egyptian breeds of
sheep and oxen, ii. 425; on an ancient
Peruvian gourd, ii. 429.

Picoregs, effect of conditions of life on, ii.
273.

Picret, A., oriental names of the pigeon,
i, 205.

Pictet, Prof., origin of the dog, i. 15; on
fossil oxen, i. 81.

PIEBALDS, probably due to reversion, il.
37.

PicEavx, hybrids of the hare and rabbit,
ii, 99, 152.

PIGEON & cravate, i. 148.

Picton Bagadais, i. 142, 143.

Picron coquille, i. 155.

PIGEON cygne, i. 143.

Piceron heurteé, i. 156.

Picron Patu plongeur, i. 156.

Picton Polonais, i. 144.

Pigeon Romain, i. 142, 144.

Pigron tambour, i. 154.

Pigeon Ture, i. 139.

Picrons, origin of, i, 131-134, 180-204 ;
classified table of breeds of, i. 136;
pouter, i. 137-139; carrier, i. 139-142 ;
runt, i. 142-144; barbs, i. 144-146;
fantail, i. 146-148; turbit and owl, i.
148-149; tumbler, i. 150-153; Indian
frill-back, i. 153; Jacobin, i. 154;

trumpeter, i. 154; other breeds of, i. |
155-157 ; differences of, equal to generic, |

i. 157-158; individual variations of, i.
158-160; variability of peculiarities
characteristic of breeds in, i. 161;
sexual variability in, i. 161-162; osteo-
logy of, i, 162-167; correlation of
growth in, i. 167-171, ii. 321; young
of some varieties naked when hatched ;
i. 170, ii. 332; effects of disuse in, i.
172-177 ; settling and roosting in trees,
i. 181; floating in the Nile to drink, i.
181; Dovecot, i. 185-186; arguments
for unity of origin of, i. 188-204; feral
in various places, i. 190, ii. 33; unity
of coloration in, i. 195-197; reversion
of mongrel, to coloration of, C. livia, i.
197-202 ; history of the cultivation of,
i, 205-207; history of the principal
races of, i. 207-212; mode of production
of races of, i, 212-224; reversion in, ii.
29, 47; by age, ii. 38; produced by
crossing in, il. 40, 48; prepotency of
transmission of character in breeds of,
ii, 66-67; sexual differences in some
varieties of, ii. 74; period of perfect
plumage in, ii. 77; eftect of segregation
on, ii. 86; preferent pairing of, within
the same breed, ii. 103; fertility of, in-
creased by domestication, ii. 112, 155;
effects of interbreeding and necessity
of crossing, 125-126; indifference of,
to change of climate, ii. 161; selection
of, ii. 195, 199, 204 ; among the Romans,
ii. 202 ; unconscious selection of. ii. 211,
214; facility of selection of, ii. 234 ;
white, liable to the attacks of hawks, ii.
230; effects of disuse of parts in, ii.
298; fed upon meat, ii. 304; effect of
first male upon the subsequent progeny
of the female, i. 405; homology of the
leg and wing feathers in, ii. 323;
union of two outer toes in feather-
legged, ibid.; correlation of beak, limbs,
tongue, and nostrils in, ii. 324; analo-
gous variation in, ii, 349-350; perma-
nence of breeds of, ii. 429.

Pias, of Swiss lake-dwellings, i. 67-68;
types of, derived from Sus scrofa and
Sus indicus, i. 66-67; Japanese (Sus
pliciceps, Gray), figured, i. 69; of
Pacific islands, i. 70, ii. 87; modifica-
tions of skull in, i. 71-73; length of

‘intestines in, i. 73, ii. 303; period of
gestation of, i. 74; number of vertebrae
and ribs in, i. 74; anomalous forms, i.
75-76; development of tusks and
bristles in, i. 76; striped young of, 1.
76-77 ; reversion of feral, to wild type,
i. 77-78, ii. 33, 47; production and
changes of breeds of, by intercrossing,
i. 78; effects produced by the first
male upon the subsequent progeny of
the female, i. 404; two-legged race of,

PIMENTA.

INDEX. POOLE. 471

ii. 4; polydactylism in, ii. 14; cross-
reversion in, ii. 35; hybrid, wildness of,
ii. 45 ; monstrous development of a pro-
boscis in, ii. 57; disappearance of tusks
in male under domestication, ii, 74;
solid hoofed, ii. 429; crosses of, ii. 93,
95; mutual fertility of all varieties of,
ii. 110; increased fertility by domesti-
cation, ii. 111; ill effects of close inter-
breeding in, ii. 121-122; influence of
selection on, ii. 198; prejudice against
certain colours in, ii. 210, 229, 336;
unconscious selection of, ii. 214; black
Virginian, ii. 227, 336; similarity of the
best breeds of, ii. 241; change of form
in, ii. 279; effects of disuse of parts in,
ii. 299; ears of, ii. 301; correlations in,
ii. 327; white, buck-wheat injurious to,
ii. 337; tail of, grafted upon the back,
li. 869; extinction of the older races of,
li. 426.

Pimenta, ii. 91.

PIMPERNEL, ii. 190.

PINE-APPLE, sterility and variability of the,
ii, 262.

Pink, Chinese, 322.

Pings, bud-variation in, i. 381; improve-
ment of, ii. 216.

Pinus pumilio, Mughus, and nana, varie-
ties of P. sylvestris, i. 363.

Pinus sylvestris, i, 368, ii. 310; hybrids
of, with P. nigricans, ii. 130,

Priorry, on hereditary disease, ii. 7,
78.

Pistacia lentiscus, ii. 274.

Pistixs, rudimentary, in cultivated plants,
ii. 316.

Pistor, sterility of some mongrel pigeons,
i. 192; fertility of pigeons, ii. 112.

Pisum arvense and sativum, i. 326.

Piryriasis versicolor, inheritance of, ii.
79.

PuLancHon, G., on a fossil vine, i. 332;
sterility of Jussixa grandiflora in
France, ii. 170.

PLANE tree, variety of the, i. 362.

PLANTIGRADE carnivora, general sterility
of the, in captivity, ii. 151.

PLANTS, progress of cultivation of, i. 305-
312; cultivated, their geographical de-
rivation, i. 311; crossing of, ii. 98, 99,
127; comparative fertility of wild and
cultivated, ii. 112-113; self-impotent,
ii, 131-140; dimorphic and trimorphie,
ii, 132, 140; sterility of, from changed
conditions, ii. 163-165; from contabes-
cence of anthers, ii. 165-166; from mon-
strosities, ii. 166-167; from doubling of
the flowers, ii. 167-168; from seedless
fruit, ii. 168; from excessive develop-
ment of vegetative organs, ii. 168-171;
influence of selection on, ii. 199-201;

variation by selection, in useful parts
of, ii, 217-219; variability of, ii. 237;
variability of, induced by crossing, ii.
265; direct action of change of climate
on, li. 277; change of period of vegeta-
tion in, i. 304-805; varieties of, suit-
able to different climates, ii. 306; cor-
related variability of, ii. 330-331; an-
tiquity of races of, ii. 429.

Puiasticrry, inheritance of, ii. 241.

PuLatTEAt, F., on the vision of amphibious
animals, i1. 223.

Platessa flesus, ti. 53.

Pxato, notice of selection in breeding
dogs by, ii. 212.

Puica polonica, ii. 276.

Pury, on the crossing of shepherd's dogs
with the wolf, i. 24; on Pyrrhus’ breed
of cattle, ii. 202; on the estimation of
pigeons among the Romans, i. 205;
pears described by, ii. 215.

Pum, i. 845-347; stones figured, i. 345;
varieties of the, i. 345-346, ii. 219;
bud-variation in the, i. 375; peculiar
disease of the, ii. 227; flower-buds of,
destroyed by bullfinches, ii. 282; pur-
ple-fruited, liable to certain diseases,
ll. 336.

Piumace, inherited peculiarities of, in
pigeons, i 160-161; sexual pecu-
liarities of, in fowls, i. 251-255

Puurauiry of races, Pouchet’s views on,
| >

Poa, seeds of, used as food, i. 308 ; species
of, propagated by bulblets, ii. 170.

Popo.tAN cattle, i. 80.

Porters, modification of, i. 42; crossed
with the foxhound, ii 95.

Pots sans parchemin, ii. 231.

Porrrav, origin of Cytisus Adami, i. 390;
origin of cultivated varieties of fruit-
trees, li. 260.

Pouish fowl, i. 227, 250, 254, 256-257,
262; skull figured, i. 262; section of
skull figured, i. 263; development of
protuberance of skull, i. 250; furcula
figured, i. 268.

Potts, or Himalayan rabbit, i. 108.

POLLEN, ii. 363-364; action of, ii. 108; in-
jurious action of, in some orchids, ii. 134-
135; resistance of, to injurious treat-
ment, ii. 164; prepotency of, ii. 187.

Poutock, Sir F., transmission of variegated
leaves in Ballota nigra, i. 383; ou local
tendency to variegation, ii. 274.

PoLYANTuUs, ii. 21.

Potypacry.ism, inheritance of, ii. 12-16;
significance of, ii. 16-17.

Polyplectron, i. 255.

Pontes, most frequent on islands and
mountains, i. 52; Javanese, i. 53.

Poots, Col., on striped Indian horses, i.

472

POPLAR.

INDEX.

QUATREF AGES.

98, 59; on the

li. 43.

Popiar, Lombardy, i. 361,

Poppie, on Cuban wild dogs, i. 27,

Poppy, found in the Swiss lake-dwellings,
i, 317, 319; with the stamens con-
verted into pistils, i. 365; differences
of the, in different parts of India, ii,
165; monstrous, fertility of, ii, 166;
black-seeded, antiquity of, ii, 429,

Porcupine, breeding of, in captivity, ii.
152.

Porcupine family, ii, 4, 76.

Porphyrio, breeding of a species of, in
captivity, ii. 156.

PortTAL, on a peculiar hereditary affection
of the eye, ii. 9.

Porto Santo, feral rabbits of, i. 112.

Potamocherus penicillatus, ii. 150.

Porato, i. 330-331; bud-variation by

tubers in the, i. 384-385; graft-lybrid

of, by union of half-tubers, i. 395; in-

dividual self-impotence in the, ii. 137;

sterility of, ii. 169; advantage of change

of soil to the, ii. 146; relation of tubers

and flowers in the, ii. 343.

young of Asinus indicus,

Porato, sweet, sterility of the, in China, |

ii. 169; varieties of the, suited to dif-
ferent climates, ii. 309.

PoucuEtT, M., his views on plurality of
races, 1. 2.

Povutrr pigeons, i. 137-139; furcula
figured, i. 167; history of, i. 207.

Powis, Lord, experiments in crossing
humped and English cattle, i. 83, ii. 45.

Poyntrr, Mr., on a graft-hybrid rose, i. |

396.

Prairie wolf, i. 22.

Precocity of highly-improved breeds, ii.
321.

PrREPOTENCY of pollen, ii. 187.

PREPOTENCY of transmission of character,
ii. 65, 174; in the Austrian emperors
and some Roman families, ii. 65;
in cattle, 65-66; in sheep, 66; in cats,
ibid. ; in pigeons, 66-67; in fowls, 67;
in plants, ibid.; in a variety of the
pumpkin, ii. 358 ; in the jackal over the
dog, ibid.; in the ass over the horse,
ibid.; in the pheasant over the fowl,
68; in the penguin duck over the
Egyptian goose, ibid. ; discussion of the
phenomena of, 69-71. ;

Prescorr, Mr., on the earliest known
European flower-garden, ii. 217.
Pressure, mechanical, a cause of modifi-

cation, ii. 344-345.
Prevost and Dumas, on the employment

of several spermatozoids to fertilise one |

ovule, ii. 363.
Price, Mr., variations in the structure of
the feet in horses, i. 50.

|
|
|

{

Pricuarp, Dr., on polydactylism in the
negro, li. 14; on the Lambert family,
il. 77; on an albino negro, li. 229; on
Plica polonica, ii. 276.

PRimrosg, ii. 21; double, rendered single
by transplantation, ii. 167.

Primula, intercrossing of species of, i.
336; contabescence in, ii. 166; hose
and hose, i.365; with coloured calyces,
sterility of, ii. 166.

Primula sinensis, reciprocally dimorphic,
li. 132.

Primula veris, ii. 21, 109, 182.

Primula vulgaris, ii. 21, 109.

Princg, Mr.,on the intercrossing of straw-
berries, i. 352.

Procyon, sterility of, in captivity, ii. 152.

PRoLIFICAcy, increased by domestication,
ii. 174,

PROPAGATION, rapidity of, favourable to
selection, ii. 297.

Prorozoa, reproduction of the, ii. 376.

Prunus armeniaca, i. 844-345.

Prunus avium, i. 347.

* Prunus cerasus, i. 847, 375.

Prunus domestica, i. 345.

Prunus insititia, i. 845-347.

Prunus spinosa, i. 345.

PrusstA, wild horses in, i. 60.

Psittacus erithacus, ii. 155.

Psittacus macoa, ii. 155.

Psophia, general sterility of, in captivity,
iy 187,

PrarmicGan fowls, i. 228.

Pulex penetrans, ii. 275.

PumPkxIns, i. 357,

Puno ponies of the Cordillera, i. 52.

Purser, Mr. on Cytisus Adami, i. 389.

Pusey, Mr., preference of hares and rab-
bits for common rye, ii. 232.

PurscuEe and Vertuch, varieties of the
potato, i. 330.

_ Povis, effects of foreign pollen on apples,

i, 401; supposed non-variability of mo-
notypic genera, ii. 266.

Pyrrhula vulgaris, ii. 232 ; assumption of
the hen-plumage by the male, in con-
finement, ii. 153.

Pyrruvs, his breed of cattle, ii. 202.

Pyrus, tastigate Chinese species of, ii.
277.

Pyrus acerba, i. 348.

| Pyrus aucuparia, ii. 230.

Pyrus communis, i. 350, 376.
Pyrus malus, i. 348, 376.
Pyrus paradisiaca, i. 348.

| Pyrus precon, i. 348,

Quacea, effect of fecundation by, on the
subsequent progeny of a mare, i. 403-
404.

QUATREFAGES, A. de, on the burrowing of

—————

act Ria

QUERCUS.

INDEX.

473

REVERSION,

a bitch to litter, i. 77; selection in the
silkworm, i. 301; development of the
wings in the silkmoth, i. 303, i. 298;
on varieties of the mulberry, i. 334;
special raising of eggs of the silkmoth,
ii. 197; on disease of the silkworm, ii.
228; on monstrosities in insects, il. 269,
391; on the Anglo-Saxon race in
America, ii. 276; on a change in the
breeding season of the Egyptian goose,
ii. 304; fertilisation of the Teredo, ii.
363; tendency to similarity in the best
races, ii. 241; on his “tourbillon vital,”
ii. 61; on the independent existence of
the sexual elements, ii. 360.

Quercus cerris, i. 363.

Quercus robur and pedunculata, hybrids
of, ii. 130.

QUINCE, pears grafted on the, ii. 259.

Rasstrs, domestic, their origin, 1. 103-105 ;
of Mount Sinaiand Algeria, i. 105; breeds
ot; 1.
Polish, or Russian, i. 108-111, ii. 97;
feral, i. 111-115; of Jamaica, i. 112; of
the Falkland islands, i. 112; of Porto
Santo, i. 112-115, ii. 103, 279; osteo-
logical characters of, i, 115-129; dis-
cussion of modifications in, i. 129-130;
one-eared, transmission of peculiarity
of, ii. 12; reversion in feral, ii. 33; in
the Himalayan, ii. 41; crossing of
white and coloured Angora, ii. 92 ; com-
parative fertility of wild and tame, ii.
111; high-bred, often bad breeders, ii.
121; selection of, ii. 204; white, liable
to destruction, ii. 230; effects of disuse
of parts in, ii, 298; skull of, affected
by drooping ears, ii. 301; length of in-
testines in, ii. 303; correlation of ears
and skull in, ii. 8324-325; variations in
skull of, ii. 350; periosteum of a dog
producing bone in, ii. 369.

RACcE-HORSE, origin of, i. 54.

Races, modification and formation of,
by crossing, ii. 95-99; natural and
artificial, ii. 245; Pouchet’s views on
pee of, i. 2; of pigeons, i. 207-

12,

RaDISHES, 1. 326; crossing of, ii. 90; va-
rieties of, ii. 217-218.

Ravctyrres, W. F., effect of climate and
soil on strawberries, i. 354; constitu-
tional differences in roses, i. 367.

RADLKOFER, retrogressive metamorphosis
in mosses and alge, ii. 36]. :

RaFF.gs, Sir Stamford, on the crossing of
Javanese cattle with Bos sondaicus, ii.
206.

Ram, goat-like, from the Cape of Good
Hope, ii. 66.

RancuHIN, heredity of diseases, ii. 7.

105-111; Himalayan, Chinese, |

|

Rance of gallinaceous birds on the Hima-
laya, i. 237.
Ranunculus ficaria, ti. 170.

| Ranunculus repens, ii. 168.

Rape, i. 325.

‘Raphanus sativus, ii. 343.

RaspsBerry, yellow-fruited, ii. 230.

RATTLESNAKE, experiments with poison
of the, ii. 289.

Raven, stomach of, affected by vegetable
diet, ii. 302.

Rawsoy, A., self-impotence in hybrids of
Gladiolus, ii. 139-140.

Re, Le Compte, on the assumption of a
yellow colour by all varieties of maize,
i, 321,

Reavmvr, effect of confinement upon the
cock, ii. 52; fertility of fowls in most
climates, ii. 161.

Reep, Mr., atrophy of the limbs of rab-
bits, consequent on the destruction of
their nerves, ii. 297.

REGENERATION of amputated parts in man,
ii. 14; in the human embryo, ii. 15; in
the lower vertebrata, insects, and my-
riapoda, ibid,

REINDEER, individuals recognised by the
Laplanders, ii. 251.

Reenter, early cultivation of the cabbage
by the Celts, i. 324. -

REISssEK, experiments in crossing Cytisus
purpureus and laburnum, i. 389; modi-
fication of a Thesium by Hcidium, il.
284.

Retations, characters of, reproduced in
children, ii, 34.

RENGGER, occurrence of jaguars with
crooked legs in Paraguay, i.17; naked
dogs of Paraguay, i. 23, 31, 11. 93, 102;
feral dogs of La Plata, i. 27; on the
aguara, i. 26; cats of Paraguay, i. 46,
ii. 86, 151; dogs of Paraguay, ii. 87;
feral pigs of Buenos Ayres, i. 77; on
the refusal of wild animals to breed in
captivity, ii. 149; on Dicotyles labiatus,
ii. 150; sterility of plantigrade car-
nivora in captivity, ii. 152; on Cavia
aperea, ii. 152; sterility of Cebus azarx
in captivity, ii. 153; abortions pro-
duced by wild animals in captivity, ii.
158.

ReEpropucrion, sexual and asexual, con-
trasted, ii. 8361; unity of forms of, ii.
383; antagonism of, to growth, ii. 384.

Reseda odorata, ii. 237.

Retinitis, pigmentary, in deaf-mutes, ii.
328.

REVERSION, ii. 28-29, 372-373, 396, 398-
402; in pigeons, ii. 29; in cattle, ii.
29-30; in sheep, ii. 30; in fowls, ii. 31; in
the heartsease, ibid. ; in vegetables, ibid. ;
in feral animals and plants, ii. 32-34; to

474

REYNIER,

INDEX.

ROMANS.

characters derived from a previous cross
in man, dogs, pigeons, pigs, and fowls,
ii. 34-35; in hybrids, ii. 36; by bud-pro-
pagation in plants, ii. 36-38 ; by age in
fowls, cattle, &c., ii. 838-39 : caused by
crossing, ii. 89-51; explained by latent
characters, ii, 51-56; producing mon-
strosities, ii. 57; producing peloric
flowers, ii. 58-60; of feral pigs to the
wild type, i. 77-78; of supposed feral
rabbits to the wild type, i. 104, 111,
115; of pigeons, in coloration, when
crossed, i. 197-202; in fowls, i. 239-
246; in the silkworm, i. 302; in the
pansy, i. 369; ina pelargonium, i. 378;
in Chrysanthemums, i. 379; of-varie-
ties of the China rose in St. Domingo,
i. 380; by buds in pinks and carna-
tions, i. 381; of laciniated varieties of
trees to the normal form, i. 382; in
variegated leaves of plants, i. 383-384;
in tulips, i. 386; of suckers of the seed-
less barberry to the common form, i.
384 ; by buds in hybrids of Tropxolum,
i. 892; in plants, i. 409; of crossed
peloric snapdragons, ii. 71; analogous
variations due to, li. 349-351.

Reynter, selection practised by the Celts,
li. 202-203.

Rutnoceros, breeding in captivity in
India, ii. 150.

Rhododendron, hybrid, ii. 265.

Rhododendron ciliatum, ii. 277.

Rhododendron Dathousiz, effect of pollen
of R. Nuttallii upon, i. 400.

Ruvpars, not medicinal when grown in
England, ii. 274.

Ribes grossularia, i. 354-356, 376.

Ribes rubrum, i. 376.

Riss, number and characters of, in fowls,
i. 267; characters of, in ducks, i. 283-
284.

Ricg, Imperial, of China, ii. 205 ; Indian
varieties of, ii. 256; variety of, not re-
quiring water, ii. 305.

Ricuarpson, H. D., on jaw-appendages in
Irish pigs, i. 76; management of pigs
in China, i. 68; occurrence of striped
young in Westphalian pigs, i. 76 ; on
crossing pigs, ii. 95; on interbreeding
pigs, ii. 122; on selection in pigs, ii.
194,

Ricuarpson, Sir John, observations on
the resemblance between North Ame-
rican dogs and wolves, i. 21-22 ; on the
burrowing of wolves, i. 27; on the
broad feet of dogs, wolves, and foxes in
North America, i. 40; on North Ame-
rican horses scraping away the snow, i.
53.

Ricinus, annual in England, ii. 305. ‘

Riepev, on the “ Bagadotte ” pigeon, i.

141; on the Jacobin pigeon, i, 154;
fertility of hybrid pigeons, i. 192.

RINDERPEST, ii. 378,

Risso, on varieties of the orange, i. 336,
li. 308, 331.

Rivers, Lord, on the selection of grey-
hounds, ii. 235.

Rivers, Mr., persistency of characters in
seedling potatoes, i. 331: on the peach,
1, 338, 339 ; persistency of races in the
peach and nectarine, i. 339, 340; con-
nexion between the peach and the nee-
tarine, i. 340; persistency of character
In seedling apricots, i. 344; origin of
the plum, i. 345; seedling varieties of
the plum, i. 346; persistency of cha-
racter in seedling plums, i. 347; bud-
variation in the plum, i. 375; plum,
attacked by bullfinches, ii. 232; seed-
ling apples with surface-roots, i. 349;
variety of the apple found in a wood,
li. 260 ; on roses, i. 366-367 ; bud-varia-
tion in roses, i. 379-881 ; production of
Provence roses from seeds of the moss-
rose, i. 380; effect produced by grafting
on the stock in jessamine, i. 394; in
the ash, i. 394; on grafted hazels, i.
395 ; hybridisation of a weeping thorn,
ii. 18; experiments with the seed of
the weeping elm and ash, ii. 19; va-
riety of the cherry with curled petals,
li. 232.

RiviERE, reproduction of Oncidium Ca-
vendishianum, ii. 133.

Roserts, Mr., on inheritance in the horse,
ii. 10.

Rosertson, Mr.,
peaches, i. 343.

RostNet, on the silkworm, i. 301-304, ii.
197.

Robinia, ii. 274.

Rosson, Mr., deficiencies of half-bred
horses, ii. 11.

Rosson, Mr., on the advantage of change
of soil to plants, ii. 146-147; on the
growth of the verbena, ii. 273; on
broccoli, ii. 310.

Rock pigeon, measurements of the, i. 134;
figured, i. 135.

Ropenrs, sterility of, in captivity, ii, 152.

Rodriquezia, ii. 134, 135. :

Ropwet., J., poisoning of horses by mil-
dewed tares, ii. 337.

RouttcunD, feral humped cattle in, i. 79.

Rotts, F., on the history of the peach, ii.
308.

Ro.LLER-PIGEONS, Dutch, i. 151. ;

Ro.iieston, Prof., incisor teeth affected
in form in cases of pulmonary tubercle,
ii. 332. ;

Romans, estimation of pigeons by, 1. 205 ;
breeds of fowls possessed by, i. 231, 247.

on glandular-leaved

~~

ROOKS. INDEX.

SALTER. 475

Rooks, pied, ii. 77. ;

Rosa, cultivated species of, i. 366.

Rosa devoniensis, graft-hybrid produced
by, on the white Banksian rose, 1. 396.

Rosa indica and centifolia, fertile hybrids
of, i. 366.

Rosa spinosissima, history of the culture
of, i. 367.

RosELLINI, on Egyptian dogs, i. 17.

Rossgs, i. 866-367 ; origin of, i. 364; bud-
variation in, i. 379-381 ; Scotch, doubled
by selection, ii. 200; continuous varia-
tion of, ii. 241; effect of seasonal con-
ditions on, ii. 273; noisette, ii. 308 ;
galls of, ii. 284.

Rovennals rabbit, i. 105.

Rowtiy, on the dogs of Juan Fernandez,
i. 27; on South American cats, i. 46;
striped young pigs, i. 77; feral pigs in
South America, i. 78, ii. 33; on Colum-
bian cattle, i. 88, ii. 205, 226; effects
of heat on the hides of cattle in South
America, i. 92; fleece of sheep in the
hot valleys of the Cordilleras, i. 98;
diminished fertility of these sheep, ii.
161; on black-boned South American
fowls, i. 258; variation of the guinea-
fowl in tropical America, i. 294; fre-
quency of striped legs in mules, ii. 42 ;
geese in Bogota, ii. 161; sterility of
fowls introduced into Bolivia, ii. 162.

Roy, M., on a variety of Magnolia gran-
diflora, ii. 308.

Royr, Dr., Indian varieties of the mul-
berry, i. 334; on Agave vivipara, ii.
169; variety of rice not requiring irri-
gation, ii. 305 ; sheep from the Cape in
India, ii. 306.

Rubus, pollen of, ii. 268.

RupDIMENTAaRY organs, i. 12, ii. 315-318.

Rurz de Lavison, extinction of breeds of
dogs in France, ii. 425.

Ruminants, general fertility of, in cap-
tivity, ii. 150.

Rump ess fowls, i. 230.

Runts, i. 142-144; history of, i. 210;
lower jaws and skull figured, i. 164-165.

Russtan or Himalayan rabbit, i. 108.

Ritimeyer, Prof., dogs of the Neolithic
period, i. 19; horses of Swiss lake-
dwellings, i. 49; diversity of early do-
mesticated horses, i. 51; pigs of the
Swiss lake-dwellings, i. 65, 67-68 ; on
humped cattle, i. 80; parentage of
European breeds of cattle, i. 80, 81, ii,
427; on “ Niata” cattle, i. 89 ; sheep of
the Swiss lake-dwellings, i. 94, ii. 427;
goats of the Swiss lake-dwellings, i.
101; absence of fowls in the Swiss
lake-dwellings, i. 246; on crossing
cattle, ii. 98; differences in the bones
of wild and domesticated animals, ii.

279; decrease in size of wild European
animals, ii. 427.

Rye, wild, De Candolle’s observations on,
i. 313; found in the Swiss lake-dwel-
lings, i. 319; common, preferred by
hares and rabbits, ii. 232; less variable
than other cultivated plants, ii. 254.

SaBine, Mr., on the cultivation of Rosa
spinosissima, i. 367 ; on the cultivation
of the dahlia, i. 8369-370, ii. 261; effect
of foreign pollen on the seed-vessel in
Amaryllis vittata, i. 400.

Sr. Anex, influence of the pelvis on the
shape of the kidneys in birds, ii. 844.
Sr. Domineo, wild dogs of, i. 28; bud-

variation of dahlias in, i. 385.

St. Hmatre, Aug., milk furnished by
cows in South America, ii. 300; husked
form of maize, i. 320.

Sr. Joun, C., feral cats in Scotland, i. 47 ;
taming of wild ducks, i. 278.

Sr. VaLery apple, singular structure of
ee 1. 350; artificial fecundation of the,
i. 401.

Sr. Virus’ Dance, period of appearance of,
ii. 77.

SAGERET, origin and varieties of the
cherry, i. 347-348; origin of varieties
of the apple, i. 850; incapacity of the
cucumber for crossing with other spe-
cies, 1.359; varieties of the melon, i.
360; supposed twin-mongrel melon, i.
391; crossing melons, ii. 108, 129; on
gourds, ii. 108; effects of selection
in enlarging fruit, ii. 217; on the ten-
dency to depart from type, ii. 241 ; varia-
tion of plants in particular soils, ii. 278.

SALAMANDER, experiments on the, ii. 293,
341; regeneration of lost parts in the,
ii. 15, 376, 385.

Salamandra cristata, polydactylism in, ii.
14.

Sauispury, Mr., on the production of
nectarines by peach-trees, i. 341; on
the dahlia, i. 369-370.

Salix, intercrossing of species of, i. 336.

Salix humilis, galls of, ii. 282, 283.

SALL&, feral guinea-fowl in St. Domingo,
i. 294.

Satmon, early breeding of male, ii. 384.

Saurer, Mr., on bud-variation in pelar-
goniums, i. 378; in the Chrysan-
themum, i. 379; transmission of varie-
gated leaves by secd, i. 383; bud-
variation by suckers in Phlox, i. 384;
application of selection to bud-varieties
of plants, i. 411; accumulative effect
of changed conditions of life, ii. 262;
on the variegation of strawberry leaves,
ii. 274.

Sater, 8. J., hybrids of Gallus Sonneratii

476

SAMESREUTHER,

INDEX.

SELECTION.

and the common fowl, i. 234, ii. 45;
crossing of races or species of rats, ii.
87-88.

SAMESREUTHER, on inheritance
ii. 10.

SANDFORD. See DAWKINS.

Sap, ascent of the, ii. 296.

Saponaria calabrica, ii. 20.

SARDINIA, ponies of, i. 52.

Sars, on the development of the hydroida,
ii. 368.

SaTraTion of the stigma, i. 402-403.

Saturnia pyri, sterility of, in confinement, |
1157;

SAUL, on the management of prize goose-
berries, i. 356.

SAvVIGNY, varieties of the goldfish, i.
296.

Savaces, their indiscriminate use of
plants as food, i. 307-310; fondness of,
for taming animals, ii. 160.

Savi, effect of foreign pollen on maize, i.
400.

Saxifraga geum, ii. 166.

Sayzip Monammep Mvsart, on carrier-
pigeons, i, 141; on a pigeon which
utters the sound “Yahu,” i. 155.

SCANDEROONS (pigeons), i. 142, 143.

ScANIA, remains of Bos frontosus found |
in, i. 81.

Scapu.a, characters of, in rabbits, i. 123;
in fowls, i. 268; in pigeons, i. 167; alte-
ration of, by disuse, in pigeons, i. 175;

Scar.et fever, ii. 276.

SCHAAFFHAUSEN on the horses represented
in Greek statues, ii. 213.

Scuacut, H., on adventitious buds, ii.
384,

ScuLEIWsN, excess of nourishment a cause
of variability, ii. 257.

ScHomBurck, Sir R., on the dogs of the
Indians of Guiana, i. 19, 23, ii. 206;
on the musk duck, i. 182; bud-varia-
tion in the Banana, i. 877; reversion of
varieties of the China rose in St. Do-
mingo, i. 380; sterility of tame parrots
in Guiana, ii. 155; on Dendrocygna
viduata, ii. 157; selection of fowls in
Guiana, ii. 209.

ScHREIBERS, on Proteus, ii. 297.

Sciuropterus volucella, ii. 152.

Sciurus palmarum and cinerea, ii. 152.

Sciater, P. L., on Asinus teniopus, i. 62,
ii. 41; on Asinus indicus, ii. 42; striped
character of young wild pigs, i. 70;
osteology of Gallinula nesiotis, i. 287;
on the black-shouldered peacock, i. 290 Cid
on the breeding of birds in captivity,
ii; 357.

ScHMERLING, Dr., varieties of the dog,
found in a cave, i. 19,

in cattle,

Scorcu fir, local variation of, i. 363.

ae kail and cabbage, cross between,

li. 98,

Scorr, John, irregularities in the sex of
the flowers of Maize, i. 321 ; bud-varia-
tion in Imatophyllum miniatum, i. 385 ;
crossing of species of Verbuscum, ii. 106-
107 ; experiments on crossin g¢ Primule,
i. 109 ; reproduction of orchids, ii, 133;
fertility of Oncidium divaricatum, ii.
164; acclimatisation of the sweet pea
i India, ii. 811; number of seeds in
Acropera and Gongora, ii. 379.

Scorr, Sir W., former range of wild cattle
in Britain, i. 85.

ieee on the Scotch deerhound, ii. 73,

SEBRIGHT, Sir John, effects of close inter-
breeding in dogs, ii, 121; care taken
by, in selection of fowls, ii, 197,

Secale cereale, ii, 254.

Srepewick, W., effects of crossing on the
female, i. 404; on the “ Porcupine-
man,” li. 4; on hereditary diseases, ii.
7 ; hereditary affections of the eye, li. 9,
78-79 ; inheritance of polydactylism and
anomalies of the extremities, ii, 13-14;
morbid uniformity in the same family,
ii. 17; on deaf-mutes, ii. 22; inherit-
ance of injury to the eye, ii. 24; ata-
vism in diseases and anomalies of struc-
ture, il. 84; non-reversion to night-blind-
ness, i.36; sexual limitation of the
transmission of peculiarities in man, ii.
72-73; on the effects of hard-drinking,
ii, 289; inherited baldness with defi-
ciency of teeth, ii 326-327; occurrence
of a molar tooth in place of an incisor,
ii. 891; diseases occurring in alternate
generations, ii. 401.

SEDILLOT, on the removal of portions of
bone, ii. 296,

SrEps, early selection of, ii. 204; rudi-
mentary, in grapes, ii. 316; relative
position of, in the capsule, ii. 345.

Sreps and buds, close analogies of, i. 411.

SEEMANN, B., crossing of the wolf and Es-
quimaux dog, i, 22.

| Sevsy, P. J., on the bud-destroying habits

of the bullfinch, ii. 232.

SELECTION, ii. 192-249; methodical, i.
214, ii. 194-210; by the ancients and
semi-civilised people, ii, 201-210; of
trifling characters, ii. 208-210; uncon-
scious, i. 214, 217, ii. 174, 210-217;
effects of, shown by differences in most
valued parts, ii. 217-220; produced by
accumulation of variability, ii. 220-223 ;
natural, as affecting domestic produc-
tions, ii. 185-189, 224-233; as the origin
of species, genera and other groups, ii.
429-432; circumstances favourable to,
ii. 233-239; tendency of towards ex-

——_

SELECTION.

tremes, ii. 239-242; possible limit of,

ii. 242; influence of time on, ii. 2438-
244; summary of subject, ii. 246-249 ;
effects of, in modifying breeds of cattle,
i, 92, 93; in preserving the purity of
breeds of sheep, i. 99-100; in,producing
varieties of pigeons, i. 213-218; in breed-
ing fowls, i. 282-233 ; in the goose, i.
289; in the canary,i. 295; in the gold-
fish, i. 296; in the silkworm, i. 300-
301; contrasted in cabbages and cereals,
i. 323; in the white mulberry, i. 334;
on gooseberries, i. 356 ; applied to wheat,
i. 817-318; exemplified in carrots, &c.,
i. 326; in the potato, i. 331; in the
melon, i. 360; in flowering plants, i.
365; in the hyacinth, i. 8371; applied
to bud-varieties of plants, i. 411; illus-
trations of, ii. 421-428.

SELECTION, sexual, ii. 75.

SELF-IMPOTENCE in plants, ii. 131-140; in
individual plants, ii, 136-138; of hy-
brids, ii. 174.

Srtwyn, Mr., on the Dingo, i. 26.

Setys-Lonecuamps, on hybrid ducks, i.
190, ii. 46, 157; hybrid of the hook-
billed duck and Egyptian goose, i. 282.

SERINGE, on the St. Valery apple, i. 350.

SERPENT Melon, i. 360.

Serres, Olivier de, wild poultry in Gui-
ana, 1. 237. ?

Srsamum, white-seeded, antiquity of the,
li. 429.

-Seturia, found in the Swiss lake-dwell-

ings, i. 317.

Serrers, degeneration of, in India, i. 38;
Youatt’s remarks on, i. 41. ‘
Sex, secondary characters of, latent, ii.
51-52; of parents, influence of, on hy-

brids, ii. 267.

SExUAL characters, sometimes lost in
domestication, ii. 74.

SExvAL limitation of characters, ii. 71-
75.

SEXUAL peculiarities, induced by domes-
tication in sheep, i. 95; in fowls, i. 251-
257 ; transfer of, i. 255-257.

SExvuAL variability in pigeons, i. 161-
162.

SExvAL selection, ii. 75.

SHADDOCK, i. 335. :

SHAILER, Mr., on thie moss-rose, i. 379-
380.

SHANGHAI fowls, i. 227.

SHANGHAI sheep, their fecundity, i. 97.

SHAN ponies, striped, i. 58.

SHEEP, disputed origin of, i. 94; early
domestication of, i. 94; large-tailed, i.
94, 95, 98, ii. 279; variations in horns,
mamm and other characters of, i. 95;
sexual characters of, induced by domes-
tication, i. 95, 96; adaptation of, to eli-

INDEX.

SILK-FOWLS. _ 477

mate and pasture, i. 96, 97; periods of
gestation of, i. 97; effect of heat on the
fleece of, i. 98-99, ii. 278: effect of
selection on, i. 99-101; “ancon” or
“otter” breeds of, i. 17, 92, 100;
“ Mauchamp-merino,” i. 100-101; cross
of German and merino, ii. 85-89 ; black,
of the Tarentino, ii. 227; Karakool,
ii. 278; Jaffna, with callosities on the
knees, ii. 302 ; Chinese, ii. 315; Danish,
of the bronze period, ii. 427; polydac-
tylism in, ii. 14; occasional production
of horns in hornless breeds of, ii. 30;
reversion of colour in, ii. 30; influence
of male, on offspring, ii. 68 ; sexual dif-
ferences in, ii. 73; influence of crossing
or segregation on, ii. 86, 95-96, 102-
103; interbreeding of, ii. 119-120;
effect of nourishment on the fertility
of, ii. 111-112; diminished fertility of,
under certain conditions, ii. 161; un-
conscious selection of, ii. 213; natural
selection in breeds of, ii. 224, 225, 227;
reduction of bones in, ii. 242 ; individual
differences of, ii. 251; local changes
in the fleece of, in England, ii. 278;
partial degeneration of, in Australia,
ii. 278; with numerous horns, ii. 291;
correlation of horns and fleece in, ii. 326 ;
feeding on flesh, ii. 303; acclimatisa-
tion of, ii. 305-306; mountain, resistance
of, to severe weather, ii. 312; white,
poisoned by Hypericum crispum, ii.
337.

Sueep dogs resembling wolves, i. 24.

SHELLS, sinistral and dextral, ii. 53.

Suzrrrr, Mr. new varieties of wheat, i.
315, 317; on crossing wheat, ii. 104-
105; continuous variation of wheat, ii.
241,

Sram, cats of, i. 47; horses of, i. 53.

SHIRLEY, E. P., on the fallow-deer, ii.
103, 120.

Suort, D., hybrids of the domestic cat
and Felis ornata, i, 45.

SrpertA, northern range of wild horses in,
VB

SIcHEL, J., on the deafness of white cats
with blue eyes, ii. 329.

Sipney, S., on the pedigrees of pigs, ii. 3;
on cross-reversion in pigs, ii. 35; period
of gestation in the pig, i. 74; produc-
tion of breeds of pigs by intercrossing,
i. 78, 95; fertility of the pig, ii, 112;
effects of interbreeding on pigs, ii. 121-
122; on the colours of pigs, ii. 210,
229.

SIEBOLD, on the sweet potato, ii. 309.

SIEBOLD, von Carl, on parthenogenesis, ii,
364.

Silene, contabescence in, ii. 166.

SILK-FOWLS, i. 230, ii. 67, 69.

d 78 SILK-MOTH.

Si.K-moru, Arrindy, ii. 306, 312; Tarroo,
ii. 157.

SILK-MoTHS, i. 300-304; domesticated
species of, i. 300; history of, ibid. ;
causes of modification in, i, 300-301 :
differences presented by, i. 301-304 ;
crossing of, ii. 98; disease in, ii. 228;
effects of disuse of arts in, ii, 298 ;
selection practised with, ii, 197, 199;
variation of, ii. 236; parthenogenesis
in, ii. 364,

SILKWoRMS, variations of, i. 301-302 ;
yielding white cocoons, less liable to
disease, ii. 336.

Sitver-Grey rabbit, i. 108, 111, 120.

Sumonps, J. B., period of maturity in
various breeds of cattle, i. 87; differ-
ences in the periods of dentition in
sheep, i. 96; on the teeth in cattle,
sheep, &c., ii. 322; on the breeding of
superior rams, ii. 196.

Simon, on the raising of eggs of the silk-
moth in China, ii. 197.

Srupson, Sir J., regenerative power of the
human embryo, ii. 15.

Stredon, breeding in the branchiferous
stage, ii. 384.

Sisk1n, breeding in captivity, ii. 154.

Sivatherium, resemblance of the, to Niata
cattle, i. 89.

Size, difference of, an obstacle to crossing,
ii. 101.

Skin, and its appendages, homologous,
ii. 325; hereditary affections of the,
i. 78;

Sxirvine, R. §., on pigeons settling on
trees in Egypt, i. 181.

SKULL, characters of the, in breeds of
dogs, i. 84; in breeds of pigs, i. 71; in
rabbits, i. 116-120, 127; in breeds of
pigeons, i. 163-165; in breeds of fowls,
1. 260-266 ; in ducks, i, 282-283.

Sku and horns, correlation of the, ii.
333.

SKYLARK, ii. 154.

SLEEMAN, on the Cheetah, ii. 151.

Stop, i. 345.

SMALL-POX, Ii. 378.

SmITER (pigeon), i. 156.

Smiru, Sir A., on Caffrarian cattle, i. 88;
on the use of numerous plants as food
in South Africa, i. 307.

Smrru, Colonel Hamilton, on the odour of
the jackal, i. 30; on the origin of the
dog, i. 16; wild dogs in St. Domingo,
i, 28; on the Thibet mastiff and the
alco, i. 28-29 ; development of the fifth
toe in the hind feet of mastiffs, i. 35 ;
differences in the skull of dogs, i, 34;
history of the pointer, i. 42; on the ears
of the dog, ii. 301; on the breeds of

horses, i. 49; origin of the horse, i. 51 ; |

INDEX.

SPECIES.

dappling of horses, i. 55 ; striped horses
in Spain, i. 58; original colour of the
horse, i. 60; on horses scraping away
snow, 1, 52; on Asinus hemionus, ii. 43 c
feral pigs of Jamaica, i. 77-78.

Suiru, Sir J. E., production of nectarines
and peaches by the same tree, i. 340;
on Viola amena, i. 368; sterility of
Vinea minor in England, ii. 170.

Smiru, J., development of the ovary in
Bonatea speciosa, by irritation of the
stigma, i. 403.

Smiru, N. H., influence of the bull “ Fa-
vourite” on the breed of Short-horn
cattle, ii. 65.

Smitu, W., on the inter-crossing of straw-
berries, i. 352.

SNAKE-RAT, ii. 87, 88.

Snakes, form of the viscera in, ii. 344.

SNAPDRAGON, bud-variation in, i. 381 .
non-inheritance of colour in, ii, 21;
peloric, crossed with the normal form,
li. 70, 93; asymmetrical variation of
the, ii. 322.

Som, adaptation of plums to, i. 846; in-
fluence of. on the zones of pelargoniums,
i. 366; on roses, i. 367; on the variega-
tion of leaves, i. 383; advantages of
change of, ii. 146-148.

Som and climate, effects of, on straw-
berries; i. 353.

Solanum, non-intercrossing of species of,
ii. Ot.

Solanum tuberosum, i. 330-331.

SOLID-HOOFED pigs, i. 75.

Sotomon, his stud of horses, i. 55.

Somervi.z, Lord, on the fleece of Merino
sheep, i. 99 ; on crossing sheep, ii. 120;
on selection of sheep, ii. 195; dimin-
ished fertility of Merino sheep brought
from Spain, ii. 161.

Sooty fowls, i. 230, 256.

Soro, Ferdinand de, on the cultivation of
native plants in Florida, i. 312.

Sorghum, i. 371.

Spain, hawthorn monogynous in, i. 364.

SPALLANZANI, on feral rabbits in Lipari,
i. 113; experiments on salamanders, ii.
15, 293, 385; experiments in feeding a
pigeon with meat, ii. 304.

SPANIELS, in India, i.38; King Charles's,
i, 41 ; degeneration of, caused by inter-
breeding, ii. 121.

SpanisH fowls, i. 227, 250, 253; figured,
i. 226; early development of sexual
characters in, i. 250, 251; furcula of,
figured, i. 268.

Specins, difficulty of distinguishing from
varieties, i. 4; conversion of varieties
into, i. 5; origin of, by natural selec-
tion, ii. 414-415 ; by mutual sterility of
varieties, ii. 185-189.

Sc = ee

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—

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SPENCER.

INDEX.

STURM, 479

Spencer, Lord, on selection in breeding,
ii. 195. :

Spencer, Herbert, on the “ survival of the
fittest,” i. 6; increase of fertility by
domestication, ii. 111; on life, ii. 148,
177; changes produced by external
conditions, ii. 281; effects of use on
organs, ii. 295, 296; ascent of the sap
in trees, li. 296 ; correlation exemplified
in the Irish elk, ii. 833-334 ; on “ phy-
siological units,” ii. 375; antagonism of
growth and reproduction, ii. 384; for-
mation of ducts in plants, ii. 300.

SPERMATOPHORES of the cephalopoda, ii.
383.

SperMATOZOIDS, ii. 363-364; apparent in-
dependence of, in insects, ii, B84.

SpHINGID&, sterility of, in captivity, ii.
ESTP

Sprvona, on the injurious effect produced
by flowering buckwheat on white pigs,
li. 337.

Spitz dog, i. 31.

Spooner, W. C., cross-breeding of sheep,
i. 100, ii. 95-96, 120; on the effects of
crossing, ii. 96-97; on crossing cattle,
ii. 118; individual sterility, ii. 162.

Spores, reproduction of abnormal forms
by, i. 383.

Sports, i. 373 ; in pigeons, i. 213.

Spor pigeon, i. 156, 207.

SPRENGEL, C. K., on dichogamous plants,
ii. 90; on the hollyhock, ii. 107; on
the functions of flowers, ii. 175.

Sprovte, Mr., inheritance of cleft-palate
and hare-lip, ii. 24.

Spurs, of fowls, i. 255; development of,
in hens, ii. 318.

SQuasHEs, i. 357.

SQUINTING, hereditary, ii. 9.

SQUIRRELS, generally sterile in captivity,
ii. 152.

Squrrres, flying, breeding in confine-
ment, ii. 152.

“ STAARHALSIGE Taube,’ i. 161.

Srac, one-horned, supposed heredity of
character in, ii. 12; degeneracy of, in
the Highlands, ii. 208.

STAMENS, occurrence of rudimentary, ii.
316; conversion of, into pistils, i. 365;
into petals, ii. 392.

Staphylea, ii. 168.

STEENsTRUP, Prof., on the dog of the
Danish Middens, i. 18; on the obliquity
of flounders, ii. 53.

ba ia J., on hereditary diseases, ii. 7,
79.

STERILITY, in dogs, consequent on close
confinement, i. 32; comparative, of
crosses, ii. 103, 104; from changed con-
ditions of life, ii. 148-165 ; occurring in

the descendants of wild animals bred

in captivity, ii. 160; individual, ii,
162; resulting from propagation by
buds, cuttings, bulbs, &e., ii. 169; in
hybrids, ii. 178-180, 386, 410-411; in
specific hybrids of pigeons, i. 193; as
connected with natural selection, ii.
185-189.

Sternvum, characters of the, in rabbits, i.
123; in pigeons, i. 167, 174-175; in
fowls, i. 268, 273: effects of disuse on
the, i. 174-175, 273.

STEPHENS, J. F., on the habits of the
Bombycide, i. 303.

STEWART, H., on hereditary disease, ii. 79.

STieMA, variation of the, in cultivated
Cucurbitacee, i. 359; satiation of the,
i, 402-403.

Stocks, bud-variation in, i. 881; effect of
crossing upon the colour of the seed of,
i. 398-399; true by seed, ii. 20; crosses
of, ii. 93 ; varieties of, produced by se-
lection, ii. 219; reversion by the upper
seeds in the pods of, ii. 347-348,

STockHom, fruit-trees of, ii, 307.

Sroxgs, Prof., caleulation of the chance
of transmission of abnormal peculi-
arities in man, ii. 5.

STOLoNs, variations in the production of, by
strawberries, i. 353.

Sromacu, structure of the, affected by
food, ii. 302.

Sronz in the bladder, hereditary, ii. 8, 79.

STRAWBERRIES, i. 351-354; remarkable
varieties of, i. 252-353; hautbois, di-
cecious, i. 353; selection in, ii. 200;
mildew of, ii. 228; probable further
modification of, ii. 243; variegated,
effects of soil on, ii. 274.

STRICKLAND, A., on the domestication of
Anser ferus, i. 287; on the colour of the
bill and legs in geese, i. 288,

Stricteenas, i. 183.

STRIPES on young of wild swine, i. 76; of
domestic pigs of Turkey, Westphalia,
and the Zambesi, i. 76-77; of feral
swine of Jamaica and New Granada, i.
77; of fruit and flowers, i. 400, ii. 37;
in horses, i. 56-60 ; in the ass, i. 62-63;
production of, by crossing species of
Equide, ii. 42-43.

Strix grallaria, ii. 302.

Strix passerina, ii. 154.

* Srrupp-Tavse,”’ i. 155.

Srrurners, Mr., osteology of the feet in
solid-hoofed pigs, i. 75; on polydactyl-
ism, ii, 13-14.

Sturm, prepotency of transmission of
characters in sheep and cattle, ii. 66 ;
absorption of the minority in crossed
races, ii. 88; correlation of twisted

horns and curled wool in sheep, ii.
326.

Ee EA IR TE a OE OT Re ee

480

SUB-SPECIES.

INDEX, |

TEGETMEIER,

Sus-specigs, wild, of Columba livia and
other pigeons, i. 204.

Succussion, geological, of organisms, i, 11.

Suckers, bud-variation by, i. 384.

Sugar cane, sterility of, in various coun-
tries, ii. 169; white, liability of, to dis-
ease, ii. 228, 336.

Surcmwe, hereditary tendency to, ii. 7, 78.

Suuttvan, Admiral, on the horses of the
Falkland Islands, i. 53; wild pigs of
the Falkland Islands, i.77; feral cattle
of the Falkland Islands, i. 86, 102 ; feral
rabbits of the Falkland Islands, i. 112.

SuLTANn fowl, i. 228, 255.

Sus indicus, i. 65, 67-70, ii. 110.

Sus pliciceps, i. 69 (figured).

Sus scrofa, i. 65, 66, ii. 110.

Sus scrofa palustris, i. 68.

Sus vittatus, 1. 67.

SwaLtows, a breed of pigeons, i. 156.

Swayne, Mr., on artificial crossing of
varieties of the pea, i. 397.

Sweet Peas, ii. 91; crosses of, ii. 93, 94;
varieties of, coming true by seed, ii.
20; acclimatisation of, in India, ii. 311.

Sweer William, bud-variation in, i, 381.

Swinnog, R., on Chinese pigeons, i. 28,

206; on striped Chinese horses, i. 59.

SWITZERLAND, ancient dogs of, i. 19 ; pigs
of, in the Neolithic period, i. 67-68 ;
goats of, i. 101.

Sycamore, pale-leaved variety of the, ii,
330.

Sykes, Colonel, on a Pariah dog with
crooked legs, i. 17; on small Indian
asses, 1, 62; on Gallus Sonneratit, i.
233; on the voice of the Indian Kulm
cock, i. 259; fertility of the fowl in
most climates, ii. 161.

Symmetry, hereditary departures from, ii.
12,

Symphytum, variegated, i. 384.

SypuIis, hereditary, ii. 332.

a

Syria, asses of, i. 62.

Syringa persica, chinensis, and vulgaris, ii. |

164.

Tacrrvus, on the care taken by the Celts
in breeding animals, ii. 202.
Tagetes signata, dwarf variety of, ii. 20.

Tanti, varieties of cultivated plants in, |

ii. 256. :
TaIL, occasional development of, in man,
ii. 57; never curled in wild animals,

ii. 301; rudimentary in Chinese sheep,

li, 315.

TAIL-FEATHERS, numbers of, in breeds of
pigeons, i. 158-159; peculiarities of, in
cocks, 1. 254-255; variability of, in
fowls, i. 258; curled, in Anas boschas,
and tame drakes, i. 280.

TALENT, hereditary, ii. 7.

TANKERVILLE, Earl of, on Chillingham
cattle, i. 84, ii. 119.

Tanner, Prof., effects of disuse of parts
In cattle, ii. 299.

Tarr, sterility of the, in captivity, ii. 150.

Tareiont-Tozzerri, on cultivated plants,
1, 306; on the vine, i. 332; varieties
of the peach, i. 342; origin and varie-
ties of the plum, i. 345; origin of the
cherry, i. 347; origin of roses, i. 366.

Tarsus, variability of the, in fowls, i.
oe : reproduction of the, in a thrush,
i. 15.

Tarrars, their preference for spiral-
horned sheep, ii. 209.

TAVERNIER, abundance of
Persia, i. 205.

Taxus baccata, ii. 18.

pigeons in

| Trespay, Mr,, reversion in fowls, ii. 38,

TEETH, number and position of, in dogs,
1. 84; deficiency of, in naked Turkish
dogs, i. 35; period of appearance of,
in breeds of dogs, i. 85; precocity of,
in highly bred animals, ii. 322 ; corre-
lation of, with hair, ii. 326; double
row of, with redundant hair, in Julia
Pastrana, ii. 828; affected in form by
hereditary syphilis and by pulmonary
tuberele, ii. 332; fusion of, ii, 341;
developed on the palate, ii. 391.

TEGETMEIER, Mr., on a cat with monstrous
teeth, i. 48; on a swift-like pigeon, i.
157; naked young of some pigeons, i.
170; fertility of hybrid pigeons, i. 192;
on white pigeons, ii. 230; reversion in
crossed breeds of fowls, i, 239-244;
chicks of the white silk-fowl, i. 249;
development of the cranial protuber-
ance in Polish fowls, i. 250; on the
skull in the Polish fowl, i. 257, 262;
on the intelligence of Polish fowls, i.
264; correlation of the cranial pro-
tuberance and crest in Polish fowls, i.
274; development of the web in the
feet of Polish fowls, i. 259; early de-
velopment of several peculiarities in
Spanish cocks, i. 250; on the comb in
Spanish fowls, i. 253; on the Spanish
fowl, ii. 306; varieties of game-fowls,
i, 252; pedigrees of game-fowls, ii. 3;
assumption of female plumage by a
game cock, i. 253; natural selection in
the game cock, ii. 225; pugnacity of
game hens, i. 256; length of the
middle toe in Cochin fowls, i. 259;
origin of the Sebright bantam, ii. 54;
differences in the size of fowls, i. 257:
effect of crossing in fowls, i. 258, ii. 96 ;
effects of interbreeding in fowls, U1.
124-125; incubation by mongrels of
non-sitting races of fowls, ii. 44; m-
verse correlation of crest and comb in

T'EMMINCK. INDEX. TRITICUM. 481

fowls, i. 274; occurrence of pencilled | Thuja pendula or filiformis, a variety of

. feathers in fowls, ii. 40; on a variety
of the goose from Sebastopol, i. 289 ;
on the fertility of the peahen, ii. 112;
on the intercrossing of bees, il. 126.

TEMMINCK, origin of domestic cats, i. 43 ;
origin of domestic pigeons, i. 180; on
Columba guinea, i. 182; on Columba
leucocephala, i. 183; asserted reluct-
ance of some breeds of pigeons to cross,
i, 192; sterility of hybrid turtle-doves,
1.193; variations of Gallus bankiva, i.
235; on a_ buff-coloured breed of
Turkeys, i. 293; number of eggs laid
by the peahen, ii. 112; breeding of
Guans in captivity, ii. 156; behaviour
of grouse in captivity, ébid.; sterility
of the partridge in captivity, cbid.

TENDRILS in Cucurbitacex, i. 358, ii. 316.

TENNENT, Sir J. E., on the goose, i. 287;
on the growth of the apple in Ceylon,
ii. 277; on the Jaffna sheep, ii. 302.

Teredo, fertilisation in, ii. 363.

TERRIERS, wry-legged, ii. 245; white,
subject to distemper, ii. 336.

TESCHEMACHER, on a husked form of
maize, i. 320.

TesstEr, on the period of gestation of the
dog, i. 29; of the pig, i. 74; in cattle,
i, 87; experiments on change of soil,
ii. 147,

Tetrao, breeding of species of, in captivity,
ii, 156,

Tetrapteryx paradisea, ti. 156.

Teucrium campanulatum, pelorism in, ii.
345.

Texas, feral cattle in, i. 85.

oe his notice of the domestic fowl,
i. 246.

a ae his notice of the peach, ii.

Thesium, ii. 284.

THompson, Mr., on the peach and nec-
tarine, i. 342; on the varieties of the
apricot, i. 344; classification of varie-
ties of cherries, i. 347-348: on the
‘Sister ribston-pippin,” i. 350; on the
varieties of the gooseberry, i. 354, 355.

THompson, William, on the pigeons of
Islay, i. 184; feral pigeons in Scotland,
i. 190; colour of the bill and legs in
geese, i, 288 ; breeding of Tetrao scotius
in captivity, ii. 156; destruction of
black-fowls by the osprey, ii. 230.

Tuompson, Prof. W., on the obliquity of
the flounder, ii. 53.

THORNS, reconyersion of, into branches,

is in pear pee ii. 318.

HORN, grafting of early and late. i. :
Glastonbury, i. 364. eee

THRUSH, asserted reproduction of the
tarsus in a, ii, 15.

VOL. IT.

T. orientalis, i. 362.

TuurEtT, on the division of the zoospores
of an alga, ii. 378.

Tuwattes, G. H., on the cats of Ceylon,
1.46; on a twin seed of Fuchsia coc-
cinea and fulgens, i. 391.

TrBvrtius, experiments in rearing wild
ducks, i. 278.

Ticer, rarely fertile in captivity, ii. 150,
151.

Tigridia conchifora, bud-variation in, i.

Tre, importance of, in the production of
races, li. 243.

TrnzMANN, self-impotence in the potato,
ii. 187.

Tissuns, affinity of, for special organic
substances, ii. 380.

Trrmice, destructive to thin-shelled wal-
nuts, i, 356; attacking nuts, i. 357;
attacking peas, ii. 231.

Topacco, crossing of varieties of, ii. 108 ;
cultivation of in Sweden, ii. 307.

Toso.sk, red-coloured cats of, i. 47.

Tors, relative length of, in fowls, i.
259; development of fifth in dogs, ii.
317.

Tottet, Mr., his selection of cattle, ii
199.

Tomato, ii. 91.

Tomtits. See Titmice.

Tonaus, relation of, to the beak in pigeons,
i. 168.

Tooru, occurrence of a molar, in place of }
an incisor, ii. 391.

“ 'TORFSCHWED,” i. 68.

TraiL, R., on the union of half-tubers of
different kinds of potatoes, i. 395.

TreEs, varieties of, suddenly produced, i.
361; weeping or pendulous, i. 361;
fastigate or pyramidal, i. 361; with
variegated or changed foliage, i. 362;
early or late in leaf, i. 362-863; forest,
non-application of selection to, ii.
237.

“ 'TREMBLEUR ” (pigeons), i. 146.

TREMBLEY, on reproduction in Hydra, ii.
359.

“ 'TREVOLTINI” silkworms, i. 301-302.

Trichosanthes anquina, i. 360.

Trioks, inheritance of, ii. 6-7, 395.

Trifolium minus and repens, li. 164.

Trimorruic plants, conditions of repro-
duction in, ii. 181-184.

Tristram, H. B., selection of the drome-
dary, ii. 205-206.

Triticum dicoccum, i. 319.

Tritiewm monococcum, i. 319.

Triticum spelta, i. 319.

Triticum turgidum, i. 319.

Triticum vulgare, wild in Asia, i. 312.

27

482

TRITON

Triton, breeding in the branchiferous
stage, li. 384.

“ TROMMEL-T'AUBE,” 1. 154.

“'TRONFO” pigeon, i. 144.

Tropxolum, ii. 38.

Tropxolum minus and majus, reversion in
hybrids of, i. 392.

TROUBETZKOY, Prince, experiments with
pear-trees at Moscow, ii. 307.

Trousseau, Prof., pathological resem-
blance of twins, ii. 252.

TRUMPETER pigeon, i. 154; known in
1735, i. 207.

Tscuarner, H. A. de, graft-hybrid pro-
duced by inosculation in the vine, i.
395.

Tscuupr, on the naked Peruvian dog, i.
23; extinct varieties of maize from
Peruvian tombs, i. 320, li. 425.

Tuserrs, bud-variation by, i. 384-385.

TucKERMAN, Mr., sterility of Carex rigida,
ii. 170.

Turrep ducks, i. 281.

Tuurrs, variability of, i. 8370; bud-varia-
tion in, i. 885-386; influence of soil in
“breaking,” i. 385.

TUMBLER pigeon, i. 150-153 ; short-faced,
figured, i. 152; skull figured, i. 163;
lower jaw figured, i. 165; scapula and
furcula figured, i. 167 ; early known in
India, i. 207; history of, i. 209; sub-
breeds of, i. 220; young unable to
break the ege-shell, ii. 226; probable
further modification of, ii. 242.

“ TiMMLER ” (pigeons), i. 150.

Tumours, ovarian, occurrence of hairs
and teeth in, ii. 870; polypoid, origin
of, ii. 381.

“ TURKISOHE TAUBE,” i. 139.

TurziT (pigeon), i. 148.

Turkey, domestic, origin of, i. 292-298 ;
crossing of with North American wild
Turkey, i. 292-293; breeds of, i. 293;
crested white cock, i. 293; wild, cha-
racters of, i. 293-294 ; degeneration of,
in India, i. 294, ii. 278; failure of eggs
of, in Delhi, ii. 161 ; feral on the Parana,
i. 190; change produced in by domesti-
cation, ii. 262.

TuRKEY, striped young pigs in, i. 76.

TuRNER (pigeon), i. 156.

TurNER. W., on compensation in arteries
and veins, ii. 300; on cells, il. 37 0.

Tournies, origin of, i. 325; reversion 1n,

ii. 831; run wild, ii. 33; crosses Olsil

93, 96; Swedish, preferred by hares, ii.
932: acclimatisation of, in India, ii.
311.
TuRNSPIT, on an Egyptian monument, i.
17; crosses of the, ii. 92.
TuRTLE-DOVE, white and coloured, cross-
ing of, ii. 92.

INDEX.

VARIABILITY.

Turtur auritus, hybrids of, with T. cam-
bayensis and T’, suratensis i. 194.

| Turtur risorius, crossing of, with the
common pigeon, i. 193; hybrid of, with
T. vulgaris, ibid.

Turtur suratensis, sterile hybrids of, with
T. vulgaris, i. 193; hybrids of, with
T. auritus, i. 194.

Turtur vulgaris, crossing of, with the
common pigeon, i. 193; hybrid of,
with T. risorius, ibid.; sterile hybrids
of, with T. swratensis and LKctopistes
migratorius, ibid.

Tusxs of wild and domesticated pigs, i.
76, 77.

Tussilago farfura, variegated, i. 384.

Twin-sEED of Fuchsia coccinea and fulgens,
1.391,

TyERMAN, B., on the pigs of the Pacific
islands, i. 70, ii. 87; on the dogs of the
Pacific islands, ii. 87.

Tytor, Mr., on the prohibition of con-
sanguineous marriages, li. 122-123.

Uppers, development of the, ii. 300.

Ulex, double-flowered, ii. 167.

Ulmus campestris and effusa, hybrids of,
ii. 130.

Unirormity-of character, maintained by
crossing, li, 85-90.

Units of the body, functional independ-
ence of the, 1i. 368-371.

Unrry or plurality of origin of organisms,
be At

Upas poison, ii. 380.

Urga, secretion of, ii. 380.

Use and disuse of parts, effects of, 11. 295-
3038, 352-353, 418-419; in rabbits, 1.
124-128; in ducks, i. 284-286.

Uriiiry, considerations of, leading to uni-
formity, ii. 241.

VALENTIN, experimental production of
double monsters by, ii. 340.

Vallota, ii. 139.

Van Beck, Barbara, a hairy-faced woman,
ii. 4.

| Van Mons on wild fruit-trees, i. 312, ii.

260; production of varieties of ‘the
vine, i. 333; correlated variability in
fruit - trees, ii. 330; production of
almond-like fruit by peach-seedlings, i.
339.

| Vanessa, species of, not copulating in cap-

tivity, i. 157.

VaRrraBiuity, i. 4, ii, 871-873, 394-397,
406-420; causes of, ii, 250-270; corre-
lated, ii. 319-338, 358-355, 419-420;
law of equable, ii. 351-352; necessity
of, for selection, ii. 192 ; of selected cha-

| racters, ii. 238-239; of multiple homo-

| logous parts, ii. 342.

Cam,

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VARIATION.

Varration, laws of, ii, 293-356; conti-
nuity of, ii. 241; possible limitation of,
ii, 242, 416-417; in domestic cats, 1.
45-48; origin of breeds of cattle by, 1.
88; in osteological characters of rabbits,
i. 115-130; of important organs, 1. 399 ;
analogous or parallel, i, 348-352; in
horses, i. 55; in the horse and ass, 1.
64; in fowls, i. 243-246; in geese, 1.
288 ; exemplified in the production of
fleshy stems in cabbages, &c., i. 326;
in the peach, nectarine, and apricot, i.
342, 344; individual, in wheat, i. 314.

VaRIEGATION of foliage, i. 383, ii, 167-
168.

Varieties and species, resemblance of,
i. 4, ii, 411-413; conversion of, into
species, i. 5; abnormal, ii, 413; do-
mestic, gradually produced, ii, 414.

Varro, on domestic ducks, i, 277; on
feral fowls, ii. 38; crossing of the wild
and domestic ass, ii. 206.

Vasey, Mr., on the number of sacral ver-
tebree in ordinary and humped catile,
i. 79 ; on Hungarian cattle, i. 80.

Vaucuer, sterility of Ranunculus ficaria
and Acorus calamus, ii. 170.

VEGETABLES, cultivated, reversion in, ii.
31-32; European, culture of, in India,
il, 168-169.

Vertu, Mr., on breeds of horses, i. 49.

Verbascum, intercrossing of species of, i.
336, ii, 93, 105-107; reversion in
hybrids of, i. 392; contabescent, wild
plants of, ii. 165; villosity in, ii. 277.

Verbascum austriacum, ii. 136.

Verbascum blattaria, ii. 105-106.

Verbascum lychnitis, ti. 105-106, 136,

Verbascum nigrum, ii. 136.

Verbuscum pheniceum, ii. 107, 137; vari-
able duration of, ii. 305.

Verbascum thapsus, ii. 106.

VERBENAS, origin of, i. 364; white, lia-°

bility of, to mildew, ii. 228, 336;
scorching of dark, ii. 229, 336; effect
of changed conditions of life on, ii.
273.
Vertor, on the dark-leaved Barberry, i.
362; inheritance of peculiarities of
foliage in trees, i. 8362; production of
fiosa cannabifolia by bud-variation
from R. alba, i. 881; bud-variation in
Aralia trifoliata, i.382; variegation of
leaves, i. 383 ; colours of tulips, i. 386;
uncertainty of inheritance, ii. 18; per-
sistency of white flowers, ii. 20; peloric
flowers of Linaria, ii. 58; tendency of
striped flowers to uniformity of colour,
ii, 70; mnon-intercrossing of certain
allied plants, ii. 91; sterility of Pri-
mule with coloured calyces, ii. 166;
on fertile proliferous flowers, ibid.; on

INDEX.

VISIUN. 483

the Irish yew, ii. 241; differences in
the Camellia, ii. 251; effect of soil on
the variegated strawberry, ii. 274;
correlated variability in plants, ii. 330.

Verruca, ii. 53, 400.

VERTEBRA, characters of, in rabbits, i.
120-122 ; in ducks, i. 283-284 ; number
and variations of, in pigeons, i. 165-166 ;
number and characters of, in fowls, i.
266-268 ; variability of number of, in the
pig, i. 74.

Verrucu, see Putsche.

“ VeruGas,”’ ii. 276.

Vesructius, early cultivation in Brazil, i.
311.

Vipert’s experiments on the cultivation
of the vine from seed, i. 332.

Viburnum opulus, ti, 185, 316.

Vicia sativa, leaflet converted into a
tendril in, ii. 392.

Vicunas, selection of, ii, 207.

Vittosiry of plants, influenced by dry-
ness, li, 277.

VILMORIN, cultivation of the wild carrot,
i. 326, ii. 217; colours of tulips, i. 386;
uncertainty of inheritance in balsams
and roses, ii. 18; experiments with
dwarf varieties of Saponaria calabrica
and Tagetes signata, ii. 20; reversion of
flowers by stripes «nd blotches, ii, 37 ;
on variability, ii. 262.

Vinea minor, sterility in, ii. 170.

VINE, i. 332-334; parsley-leaved, rever-
sion of, i, 882; graft-hybrid produced
by inosculation in the, i. 8395; disease
of, influenced by colour of grapes, il.
228; influence of climate, &e., on varie-
ties of the, ii. 278; diminished extent
of cultivation of the, ii. 308; acclima-
tisation of the, in the West Indies, ii.
313.

Viola, species of, 1.368.

Viola lutea, different coloured flowers in, i.
408.

Viola tricolor, reversion in, ii. 31, 47.

Vircuow, Prof, blindness occurring in
the offspring of consanguincous mar-
riages, il. 143; on the growth of bones,
ii. 294, 381, on cellular prolification, ii.
295; independence of the elements of
the body, ii. 369 ; on the cell-theory, ii.
370; presence of hairs and teeth in
ovarian tumours, ii. 370; of hairs in
the brain, ii. 391; special affinities of
the tissues, ii. 8380; origin of polypoid
excrescences and tumours, ii. 381.

Viratt on the selection of seed-corn, i.
318, ii. 203; of cattle and sheep, ii.
202,

VirGIntAN islands, ponies of, 1. 52.

Virgularia, ii. 378.

Vision, hereditary peculiarities of, ii, 8-9 ;

Aig ee

,

484 VITIS.

INDEX.

WHEAT.

in amphibious animals, ii. 223; varie-
ties of, ii. 300; affections of organs of,
correlated with other peculiarities, ii.
328.

Vitis vinifera, 1. 332-334, 375,

Viverra, sterility of species of, in cap-
tivity, ii. 151.

VoGEL, varieties of the date palm, ii. 256.

Voert, on the indications of stripes on
black kittens, ii. 55.

Voice, differences of, in fowls, i. 259;
peculiarities of, in ducks, i. 281 ; inherit-
ance of peculiarities of, ii. 6.

Vouz, on the history of the dog, i. 16;
ancient history of the fowl, i. 246;
domestic ducks unknown to Aristotle, i.
277; Indian cattle sent to Macedonia
by Alexander, ii. 202; mention of
mules in the Bible, ii. 202; history of
the increase of breeds, ii. 244.

Von Bere on Verbascwm pheniceum, ii.
305.

VoorHeLm, G., his knowledge of hya-
cinths, 1.871, if. 261.

Vrouik, Prof., on polydactylism, ii. 12 ; on
double monsters, ii. 340; influence of

the shape of the mother’s pelvis on her
child’s head, ii. 344.

Wapers, behaviour of, in confinement, ii.
156.

WAHLENBERG, on the propagation of
Alpine plants by buds, runners, bulbs,
&e., ii. 169.

“ WAHLVERWANDTSCHAFT ” of Gartner, ii.
180.

Waters, white cattle of, in the 10th cen-
tury, i. S95.

Waker, A., on intermarriage, i. 404; on
the inheritance of polydactylism, ii. 13.

Wa ker, D., advantage of change of soil
to wheat, ii. 146.

Watiace, A. R., on a striped Javanese
horse, 1.59; on the conditions of life
of feral animals, ii. 32; artificial altera-
tion of the plumage of birds, ii. 280;
on polymorphic butterflies, i. 399-400 ;
on reversion, ii. 415; on the limit of
change, ii. 417.

Watuace, Dr., on the sterility of Sphin-
gidee hatched in autumn, ii. 158.

WALLACHIAN sheep, sexual peculiarities
in the horns of, i. 96.

WALLFLowER, bud-variation in, i. 382.

Watticu, Dr., on Thuja pendula or fili-
formis, i. 362.

Watnvts, i. 356-357; thin-shelled, at-
tacked by tomtits, ii. 231; grafting of,
li. 259.

Watsu, B. D., on galls, ii. 282, 283; his

“Law of equable variability,” ii. 351- |

352,

Watruer, F. L., on the history of the
dog, i. 16; on the intercrossing of the
zebu and ordinary cattle, i. 83.

Warrine, Mr., on individual sterility, ii.
162.

Wart hog, i. 76.

Warterer, Mr., spontaneous production of
Cytisus alpino-laburnum, i. 390.

Water melon, i. 357.

Warternotse, G. R., on the winter-colour-
ing of Lepus variabilis, i. 111.

Waterton, C., production of tailless foals,
i. 53; on taming wild ducks, i. 278;
on the wildness of half-bred wild ducks,
ii, 45; assumption of male characters
by a hen, ii. 51.

Watson, H. C., on British wild fruit-
trees, i. 312; on the non-variation of
weeds, i. 317 ; origin of the plum, i. 345;
variation in Pyrus malus, i. 348; on
Viola amena and tricolor, i. 368; on
reversion in Scotch kail, ii. 32; fertility
of Draba sylvestris when cultivated, ii.
163; on generally distributed British
plants, ii. 285.

WATTLES, rudimentary, in some fowls, ii.
315.

Warts, Miss, on Sultan fowls, i. 228.

Wess, James, interbreeding of sheep, ii.
120.

WebER, effect of the shape of the mother’s
pelvis on her child’s head, ii. 344.

WEEDS, supposed necessity for their modi-
fication, coincidently with cultivated
plants, i. 317.

WEEPING varieties of trees, i. 361.

Weeprne habit of trees, capricious inheri-
tance of, ii. 18-19.

WEEVIL, injury done to stone-fruit by, in
North America, ii. 231.

WELSH cattle, descended from Bos longi-
Jrons, i. 81.

West Indies, feral pigs of, i. 77; effect of
climate of, upon sheep, i. 98.

WestTeRN, Lord, change effected by, in
the sheep, ii. 198.

WESTPHALIA, striped young pigs in, i. 76.

Westwoop, J. O., on peloric flowers of
Catceolaria, ii. 346.

Wuate ty, Archbishop, on grafting early
and late thorns, i. 363.

Wueat, specific unity or diversity of, i.
312-318, 316-317 ; Hasora, i. 313; pre-
sence or absence of barbs in, i. 314;
Godron on variations in, ibid.; varie-
ties of, i. 314-315; effects of soil and
climate on, i. 316; deterioration of,
ibid. ; crossing of varieties of, ibid., ii.
96, 104-105, 180; in the Swiss lake-
dwellings, i. 317-319 ; selection applied
to, i. 8318, ii. 200; increased fertility of
hybrids of, with Aigélops, ii. 110; ad-

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ertility
ted, ii,
British

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WHITBY.

INDEX. YAKS. 485

eyed

vantage of change of soil to, il. 146 ;
differences of, in various parts of India,
ii. 165; continuous variation in, l.
200: red, hardiness of, ii, 229, 336 ;
Fenton, ii. 232; natural selection in,
ii. 233; varieties of, found wild, ii.
260; effects of change of climate on, il.
307; ancient variety of, ii. 429.

Wuirtsy, Mrs., on the markings of silk-
worms, i. 302; on the silkmoth, i. 303.

Waits, Mr., reproduction of supernume-
rary digits after amputation, ii, 14;
time occupied in the blending of
crossed races, ii. 87.

Wuirr, Gilbert, vegetable diet of dogs, ii.
303.

Waite and white-spotted animals, Lia-
bility of, to disease, li, 336-337.

Wuite flowers, most truly reproduced by
seed, ii. 20.

Wicuura, Max, on hybrid willows, ii. 50,
131, 267; analogy between the pollen
of old-cultivated plants, and of hybrids,
ii. 268.

Wicxine, Mr., inheritance of the primary
characters of Columba livia in cross-
bred pigeons, i. 201; production of a
white head in almond tumblers, ii.
199.

Wickstep, Mr., on cases of individual
sterility, ii. 162.

WIEGMANN, spontaneous crossing of blue
and white peas, i. 397; crossing of
varieties of cabbage, ii. 130; on conta-
bescence, ii. 165.

Wicut, Dr., sexual sterility of plants pro-
pagated by buds, &c., ii. 169.

WiLbE, Sir W. R., occurrence of Bos fron-
tosus and longifrons in Irish crannoges,
i, 81; attention paid to breeds of
animals by the ancient Irish, ii. 203.

Witpmay, on the dahlia, ii. 216, 273.

Wipness of the progeny of crossed tame
animals, ii. 44-46.

Wixes, Capt., on the taming of pigeons
among the Polynesians, ii. 161.

WitEInson, J., on crossed cattle, ii. 104,

Wituiams, Mr., change of plumage in a
Hamburgh hen, i. 258.

Wiuiams, Mr., intercrossing of straw-
berries, i. 352.

WILLIAMson, Capt., degeneration of dogs
Bis i. 87; on small Indian asses,
i. 62.

WILLiAMson, Rey. W., doubling of Ane-
mone coronaria by selection, ii. 200.

WILLOws, weeping, i. 361; reversion of
spiral-leaved weeping, i. 383; hybrids
of, ii, 267; galls of, ii, 282-283.

Witovcupy, F., notice of spot pigeons, i.
156; on a fantail pigeon, j. 208; on

tumbler pigeons, i. 209; on the turbit, |

i. 209; on the barb and carrier pigeons,
i. 211; on the hook-billed duck, i. 277.

Witwor, Mr., on a crested white Turkey
cock, i. 293; reversion of sheep in
colour, ii. 30.

Witson, B. O., fertility of hybrids of
humped and ordinary cattle in Tas-
mania, i. 83.

Wixson, Dr. prepotency of the Manx over
the common cat, ii. 66.

Witson, James, origin of dogs, i. 16.

Witson, Mr., on prepotency of transmis-
sion in sheep, ii. 69; on the breeding
of bulls, ii. 196.

WINGS, proportionate length of, in different
breeds of pigeons, i. 175-176; of fowls,
effects of disuse on, i. 270-272; charac-
ters and variations of, in ducks, i. 284-
286; diminution of, in birds of small
islands, i. 286-287.

WING-FEATHERS, number of, in pigeons, i.
159; variability of, in fowls, i. 258,

Wo tr, recent existence of, in Ireland, i.
16; barking of young, i. 27; hybrids
of, with the dog, i. 32.

Wo r-poe, black, of Florida, i. 22.

Wotves, North American, their resem-
blance to dogs of the same region, i.
21-22; burrowing of, i. 27.

Woopstry, Mr., crossing of the Ligurian
and common hive bees, i. 299, ii, 126;
variability of bees, i. 298.

Woopwarp,S.P.on Arctic Mollusca, ii. 256.

Woop, Willoughby, on Mr. Bates’ cattle,
ii. 118.

Wooter, W. <A., on the young of the
Himalayan rabbit, i. 109; persistency
of the coloured calyx in a crossed
Polyanthus, i. 365.

WorkarA poison, ii. 380.

Wovunpns, healing of, ii. 294.

Wricut, J. production of crippled calves
by shorthorned cattle, ii. 118; on selec-
tion in cattle, ii, 194; effect of close
interbreeding on pigs, ii. 121-122;
deterioration of game cocks by close :
interbreeding, ii. 124.

Wricat, Strethill, on the development
of the hydroida, ii. 368.

Wyman, Dr., on Niata cattle, and on a
similar malformation in the codfish, i.
89; on Virginian pigs, ii, 227.

XENOPHON, on the colours of hunting
dogs, ii. 209,

Ximengs, Cardinal, regulations for the
selection of rams, ii. 204.

“Yanoo,” the name of the pigeon in
Persia, i. 155.

Yaxs, domestication of, i. 82; selection
of white-tailed, ii. 206, 209.

LAE EPG EGO LOL, Li PAO RET eB] OM TEE ORT gO R TOT oR oe

486 YAM.

Yam, development of axillary bulbs in
the, ii. 169.

YARRELL, Mr., deficiency of teeth in
hairless dogs, i. 34, ii. 326; on ducks,
i. 279, ii. 262; characters of domestic
goose, resembling those of Anser albi-
frons, i. 288; whiteness of ganders, i. |
288; variations in goldfish, i. 296-297 ;
assumption of male plumage by the
hen-pheasant, ii. 51; effect of castra-
tion upon the cock, ii. 51-52; breeding |
of the skylark in captivity, ii. 154;
plumage of the male linnet in con-
finement, ii. 158; on the dingo, ii.
263.

YELLOW fever, in Mexico, ii. 276.

Yew, fastigate, ii. 241.

Yew, Irish, hardy in New York, ii. 309.

YrEw, weeping, i. 361; propagation of,
by seed, ii. 18-19.

YOuK, variations of, in the eggs of ducks,
i. 281.

Yovarr, Mr., history of the dog, i. 16-17;
variations of the pulse in breeds of
dogs, i, 85; liability to disease in

INDEX.

dogs, i. 35, ii, 227; inheritance of
goitre in dogs, li. 10; on the grey-
hound, i. 34, 41; on King Charles’
spaniels, i. 41; on the setter, i. 41; on
breeds of horses, i. 49; variation in the
number of ribs in the horse, i. 50; in-
heritance of diseases in the horse, ii.
10, 11; introduction of Eastern blood
into English horses, ii. 212-213; on
white Welsh cattle, i. 85, ii. 209; im-
provement of British breeds of cattle,
i, 93; rudiments of horns in young
hornless cattle, ii. 55, 315; on crossed
cattle, ii. 104,119; on Bakewell’s long-
horned cattle, ii. 118; selection of
qualities in cattle, ii. 196; degenera- |
tion of cattle by neglect, ii. 239; on
the skull in hornless cattle, ii, 333;

disease of white parts of cattle, ii. 337 ;

THE

ZOPF-TAUBE.

displacement of long-horned by short-
horned cattle, ii. 426; on Angola
sheep, i. 95; on the fleece of sheep, i.
99; correlation of horns and fleece in
sheep, i. 95; adaptation of breeds of
sheep to climate and pasture, i. 96;
horns of Wallachian sheep, i. 96; ex-
otic sheep in the Zoological Gardens, i.
96-97, ii. 805; oceurrence of horns in
hornless breeds of sheep, ii. 30; on the
colour of sheep, ii. 30 ; on interbreed-
ing sheep, ii. 120; on Merino rams in
Germany, ii. 196; effect of unconscious
selection on sheep, ii. 213; reversion
of Leicester sheep on the Lammermuir
Hills, ii, 224; on many-horned sheep,
ii, 326; reduction of bone in sheep,
li. 242; persistency of character in
breeds of animals in mountainous
countries, ii. 64; on interbreeding, ii.
116; on the power of selection, ii. 194-
195 ; slowness of production of breeds,
ii, 244 ; passages in the Bible relating
to the breeding of animals, ii, 201-202.

Youne, J., on the Belgian rabbit, i. 106.

Yue, Capt., on a Burmese hairy family,
ik FF, oat.

ZAamMBESI, striped young pigs on the, i. 77.

ZAMBOS, character of the, ii. 47.

ZANO, J. G., introduction of rabbits into
Porto Santo by, i, 112.

Zea Mays, i. 320.

ZEBU, i. 79; domestication of the, i. 82;
fertile crossing of, with European cattle,
i. 83, 11. 110.

ZEBRA, hybrids of, with tlie ass and mare,
ii. 42,

Zephyranthes candida, ii. 164.

Zinnia, cultivation of, ii. 261.

ZOLLINGER on Malayan penguin ducks, i.
280.

Zoospore, division of, in Alge, ii. 378.

“ ZopF-TAuBE,” i. 154.

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