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Studies on inheritance in poultry: L The con-
stitution of the White Leghorn breed*

BULLETIN 155

Agricultural Experiment Station

OF THE

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KINGSTON, R. I., U. S. A., JUNE, 1913.

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Studies on inheritance in poultry: I. The con-
stitution of the White Leghorn breed.

BULLETIN 155

v

Agricultural Experiment Station

OF THE

Rhode Island State College

KINGSTON, R. I., U. S. A., JUNE, 1913,

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BULLETIN 165^

STUDIES ON INHERITANCE IN POULTRY: I.

THE CONSTITUTION OF THE WHITE

LEGHORN BREED.t

PHILIP B. HADLEY,

With the assistance of Dorothy W. Caldwell and C. H. Magoon.

CONTEXTS.

I. Introduction p. 153.

II. Historical Resume p. 156.

III. Experimental Results p. 163.

IV. General Discussion of Results p. 182.

a. Discussion of special cases p. 186.

1. The Fi matings p. 186.

2. The F2 matings p. 190.

3. Other matings p. 194.

b. Discussion of additional crosses bearing on:

1. Constitution of the White Leghorn breed with respect to

factor / p. 205.

2. Black pigmentation latent in the White Leghorn p. 205.

♦This bulletin constitutes a part of the Twenty-sixth Annual Report for the year ending June 30 ,
1913.

tContributioD No. 19, from the Division of Animal Breeding and Pathology of the
Agricultural Experiment Station.

152 Bulletin No. 155. — 1913.

3. Relation of the White Leghorn factor I to factor / of the
Brown Leghorn (Bateson and Punnett) p. 211.

4. Occurrence of the factor for barring in breeds possessing the
R-white p. 212-

V. Summary and Conclusions p. 213.

VI. Literature Cited p. 215.

VII. Description of Plates p. 216.

L Introduction.

In the history of plant and animal breeding it has been commonly
observed that the mating of different varieties or species may produce
offspring which, in certain respects, are unlike either parent. In
some instances the qualities of this mixed, or heterozygous, individual
are an improvement upon either parent form, just as superior strains
of corn are in reahty hybrid-products, or as the crosses between cer-
tain varieties of poultry yield birds of different plumage or of larger
size than that of either parent. In the continued propagation of these
desirable types, the plant or animal breeders have, however, encoun-
tered much difficulty. This difficulty deals primarily with the follow-
ing circumstance: In the majority of cases the heterozygous form
does not breed true ; upon continued propagation it breaks up again
into the parent types, and leaves only a certain proportion of heter-
ozygous individuals which themselves, when bred further, behave
in the same manner.* In other words, no method is known of
"fixing" a heterozygous character, — of causing it to faithfully repro-
duce itself through successive generations. That knowledge of such
a method would be a valuable addition to the theory and practice of
both plant and animal breeding, no one can deny; whether it is
possible, remains to be ascertained.

The many variable features possessed by domestic poultry and the
ease with which crosses between diverse types can be made, render
this group of animals especially favorable for studying the behavior,
in inheritance, of such so-called heterozygous characters. At the
outset of this investigation, in 1909, barring in fowls was selected as
the character to be studied. The barred color-pattern in feathers
was then tentatively regarded as a heterozygous condition arising

*A case in point is that of the Blue Andalusian fowl which is a "hybrid" product and never
breeds true.

154 Bulletin No. 155.— 1913.

from the mixture of black and white. The problem was therefore,
first of all, to produce this character de novo, as it were; or at least, to
obtain it as a result of mating fowls which, in themselves or in their
ancestry, were not known to possess the condition either in a fixed
or in a transitional state; in other words, in selecting the material
to be employed in the investigation, the use of Barred Pl^Tiiouth
Rocks and other barred breeds, as well as of their ancestors and their
derivatives, was to be scrupulously avoided. Secondly, the problem
was to so breed the birds manifesting the newly-produced character
that it should be made a permanent acquisition of the breed.

As will appear in the following pages this end has in a measure
been reached,- — that is to say, a breed of barred fowl has been pro-
duced through the employment in breeding of factors found in birds
which manifested no somatic barring. But the nature of the results
secured is such as to call into question the truth of the very hypothesis
upon which the investigation was originally based. In other w^ords,
the question is now raised whether we are justified in considering the
type of barring revealed and studied in the experiments to be reported
in the light of a heterozygous character. The recently-devised
factor-hypothesis and its application to the principles of breeding
and laws of heredity, together with the theory of unit-characters, has
profoundly modified our views regarding the fundamental nature of
the things that are inherited. Thus, to discover a factor for barring
where it was not previously known to exist, and to produce such a
factor (or such a pattern) de novo by the bringing together of simpler
germinal elements, are manifestly two different operations. A dis-
cussion of the bearing of this consideration upon the results of the
present investigation may wtII be deferred until the experimental
data have been presented. It may be said here, however, that these
data may not be valueless notwithstanding that their significance now
appears to be different from that first assumed ; and the investigation
as a whole, though, perhaps not dealing with the actual "fixation"
of a heterozygous character as first surmised may still have the merit
of throwing new light upon one phase of the inheritance of the barred

Constitution of the White Leghorn Breed. 155

color-pattern; and, in addition, of producing a new type of fowl
through the isolation, and subsequent employment in breeding, of a
previously hidden factor.

The barred color-pattern is doubtless a very old and a b}^ no means
uncommon form of marking in the plumage of both wild and domestic
birds. With some modification it is present in the feathering of many
of our game birds, but it is in one or two varieties of domestic fowl
that the character is to be seen in the purest and most extended form.
At the present day the Barred Plymouth Rocks, an American breed,
represent by far the most perfect development of the barred pattern
to be found in any species or variety of bird.

The origin of barring in domestic fowls is not easy to ascertain.
It appears probable that the barring used in making the breed of
Barred Plymouth Rocks as it is known to-day was derived from the
American Dominiques. These birds, which possess less perfect
barring than the Barred Plymouth Rocks, are stated by some to have
inherited this marking from the ^'cuckoo" birds of England, but this
point is not supported by available evidence. It must therefore be
concluded that we are not acquainted with the manner by whicn the
definite barred color-pattern Was first introduced into the breeds of
domestic fowl. So far as can be ascertained, however, no new breeds
of barred fowl have been produced since the making of the American
Barred Plymouth Rocks, in which, as has been stated, the Domi-
niques were the major component. A partial exception to this state-
ment is found in the words of Wright (1910), who states that barred
birds are sometimes the result of crosses between white birds and those
of dark color. Wright assumes that barring is not a primary char-
acter [unit character], but a sort of mixture through which the breed
of Dominiques may have been founded. He further observes that
when once produced, this character '^has a strong tendency to per-
manence." These opinions of Wright were based upon observations
made from time to time in the poultry yard and without especial
study. Within the past few years, however, the method of in-
heritance of many characters in fowl has been made by several

investigators tho object of especial study and, among these characters,
that of barring has received some consideration. We may therefore
review briefly some of the recent work on this subject.

n. Historical Resume.

Hurst (1905) was among the first to test the Mendelian principles
of heredity with respect to characters of fowl. .\lt hough he did not
11 Hike a particular study of barring he makes several references to the
iil)peiirance of this color-pattern in cross-bred birds. .Vmong other
crosses was Houdan cf X White leghorn 9 . This cross "gave 94
whites and 11 blacks; of these, 22 were apjwirently clear white, 72
\vhit(* ticked with black, one black with white head, and 10 black
tick(<l with wiiite. In each case the tickings were slight ami not
ext<'nsive, so that in the grouncl color, the distinction l>etween white
and i)lack wius marked and di.scontinuous. In the first plumage all
except two of the clear whites develojx^fl black ticks, similar to those
that were born ticke<l; the blacks <levelope<l into 0 blacks and 5
'cuckoos;' 5 of the blacks were .slightly ticket! with white in the
crest only, and in their plumage were indistinguishable from the
f 'r6ve-c(rur brec^l, the other black <leveloi>e<l into a typical light
Houdan; the 5 cuckoos were gray-white, barrc^l with blue-black or
white feathers; both the blacks and the cuckoos were distinctly
shaded with brown. Curiously enough the 6 blacks were all pullets
Mild the 5 cuckoos all cockerels!'* Hut this result, as will Ix* shown
later, is wholly explainable on the groun<l that Hurst's White Leghorn
99 were heterozygous for the barred plumage character, and that
they were not pure for white.

Later, Hurst mated one of the cuckoo cockerels willi iwn of the
black pullets. From this mating, 43 chicks were hatched, all with
black down-feathers. Hut 34 were tickefl with white, 7 had white
1 leads and 2 were strongly shade<l gray. Of those hatchefl, 31 were
reared and gave, in the first plumj\ge, 17 cuckoos and 14 blacks.
"Of the cuck(K)s, 7 w«rr »M>f]<<T«'K- and 10 \vrr«^ pidlc»ts. and of the

Constitution of the White Leghorn Breed. 157

blacks, 8 were cockerels and 0 were pullets, so that the correlation of
black with 9 and cuckoo with cf in Fi was not maintained in F2."
Hurst states further that ''the cuckoos were precisely similar to those
of Fi, having a gray-white ground barred with blue-black, with odd
black or white feathers. . . . The blacks were of two t>T>es,
dark Houdans and Craves, suggesting that the cuckoo male parent
was giving off black gametes. No dominant whites appeared in this
mating, suggesting that the cuckoo male parent was not giving off
dominant white gametes."

It is interesting to note that the cuckoo cf mentioned above sub-
sequently moulted into almost clear white, only one feather on the
back being tipped with gray.

Besides the Houdan X White Leghorn cross, Hurst also crossed
Black Hamburg cf with Wiite Leghorn 9 . The progeny comprised
49 whites and 8 blacks; of these one was apparently clear white, 48
were ticked with black, and 8 were black with whitish throats. None
of these chicks were rai.sed for further observation, and Hurst draws
no conclusions regarding the origin of the barred pattern described.

Davenport (190G) has also described a type of barring which
appeared when certain black and white breeds were crossed, lii
these matings dominance of white was the usual result. Two White
Leghorns crossed by a Black Minorca proiluced in Fi only white
birds, the 99 having some black feathers White Leghorns crossed
with Houdans gave only white progeny This result is at variance
with Hurst's mentione<l above. Wiite Leghorns crossed with Red-
backed game had ''white offspring with some buff on breast." "On
the other hand," Davenport continues (p. 75), "the white color of
the Silky dominates over the dark color of the Frizzle in about only
23 per cent, of the hybrids."

Davenport states further that no barring resulted from crossing
White Leghorn with Houdan or with Black Minorca. Barring in the
male progeny did appear, however, in matings between the Tosa
fowl and White Cochin, between White Leghorn Bantam and Dark
Brahma, and in matings between White Leghorn Bantam and Rump-

158 Bulletin No. 155. — 1913.

less Game. ''Of 26 hj^brids between Black Cochin and White Leg-
horn, 8 were barred black and white, and these belonged equally to
the two sexes."

With reference to barring, Davenport in his 1906 report concludes
as follows: ''Barring is a heterozygous condition found in hybrids
from a white and black parent. It is provisionally regarded as a
form of particulate inheritance as opposed to the alternative in-
heritance of the Leghorn X Minorca cross. This heterozygous con-
dition when interbred, usually breaks up into white, uniformly
pigmented, and barred, as in the case of the Tosa X White Cochin
hybrids." As to the inheritance of white and dark plumage, Daven-
port states : "Aside from cases of barring and Andalusian coloration,
white usually dominates over dark plumage. This is true in all cases
where White Leghorn is emploj^ed as a white race, whether the other
race is Game, Dark Brahma, Houdan or Minorca. When the Silky
is used as the white race, white is sometimes recessive, but it must be
acknowledged that the dark parents were not the same as were used
with the Leghorn, but were a Game, Frizzle and Jungle fowl; con-
sequently the results in the two series are not strictly comparable ►
. . . It is hardly conceivable that the white of the Silky is different
from that of the Leghorn; so it must be concluded that the white
inherited as a solid color is sometimes dominant and sometimes
recessive, depending upon the race in which it inheres." On this
point, we now have further light as will be indicated later in this
paper.

In Davenport's later report (1909) upon inheritance of character-
istics in domestic fowl, the application of the factor hypothesis is
strongly evident, and, in the light of later researches, several of his
earlier conclusions are modified or the results receive a somewhat
different interpretation.

Among the Black X White crosses reported in this paper is the
cross White Leghorn (d^?) X Black Minorca ( 9 ?)• In 154 offspring
there appeared 116 white, black-white, or blue, and 38 black. Some
of the latter contained more or less white, and among them were four

Constitution of the White Leghorn Breed. 159

barred birds. This result approximates very closely the expected
Fi Mendelian ratio.* Since the birds that are heterozygous for white
and black appear white, we have 75 per cent, of white birds. Appar-
ently Davenport was not working with the pure-bred White Leghorn
stock.

In a cross between White Leghorn and Black Cochin there appeared
among 24 offspring, 10 white, 7 black and 7 barred. In this case
Davenport assumes that the Leghorn was heterozygous for white
(since half the progeny were not white) and heterozygous for barring.
Subsequently the barred birds which resulted from the above cross,
were mated together. This cross gave 23 white birds, 40 blacks or
games, and 21 spangled, barred or blue. Regarding this result
Davenport says: '^On the assumption that the zygotic formula of
both hens and cocks is BbN2Ww (compatible with barred plumage) ,
we get four-sixteenths of the offspring white, three-sixteenths mottled
or barred, and nine-sixteenths black or game, thus approximating^
the observed result; i. e., 21, 16, 47, as compared with 23, 21, 40. The
result supports the hypothesis of a barring factor, B."

That Davenport obtained barred birds in a cross between White
Leghorn Bantam and Dark Brahma has already been mentioned : Of
51 Fi birds, 5 were barred. An attempt was made to fix the barring.
The best cock bred from F2 and the best females from Fi or F2 were
used for the experiment. From this cross there were obtained 3
whites, 67 blacks, 37 of Dark Brahma type and 38 barred birds.
"This result," says Davenport, ''suggests the interpretation that one
of the parents, probably the male, contains both heterozygous black
and barring, while the other parent lacks the supermelanic coat and
has homozygous barring. Then, of the offspring, half will be barred
and half will be black, and consequently (since only the non-black
show their barring), one-fourth will appear barred, one-fourth will
appear of the Dark Brahma type and half will be pure black, or have
the pattern obscured by the supermelanic coat."

Besides the studies on barring reported above, dealing chiefly with
crosses between light and dark birds, the barring of the Plymouth

*Provided that the White Leghorns were heterozygous for white.

KiO Bulletin No. 155. — 1U13.

Piock breed of fowls has, within the past two or three years, received
some consideration.

The fact has long been noticed by observant poult rymen that the
progeny from crosses between Phmouth Rocks and dark non-barred
breeds varied with respect to the barred color-pattern, according as
the male bird belonged to one or the other race in question. Gush-
man (1803) was probably the first to report this circumstance.
'Diis writer made a large number of crosses between pure-bre<l fowls
witli the purpose of perfecting a good market roaster. Among his
(Tosses were Indian Game cf X Barred Plymouth Rock 9. Cush-
mnn (/, c.) gives a l)rief description of this cross and states that the
cockerels had barred plumage whereas the pullets were all black.

It is probable that other poult r>'men have observ'ed similar results
from such crosses, but without recording their observations. Yet
tlie facts obs<Tve<l awakened little speculation until the attempt was
made to place u|>on them an interpretation agn^'ing with the Men-
(Iclian view of here<lity. Spillman (l908) then devised a Mendelian
hypothesis to account for the facts observed in the inheritance of
b.irring. This hypothesis may be briefly 8tate<i as follows:

1. \Mien barring is present \n female birds, they are heterozygous
for this character; they arc also heterozygous for the female sex
character (F).

'2. When barring is present in male birds, they may be either
hdcroziigous or homozygous for this character; the males are always
homozygous for the absence of the female sex character.

3. Barring (li) and the character. '*f«'maleness" (F^. n«'Vor oxist
togeth'T in the same gamete.

This may be represent e<l symbolically i\s follows:

Let F represent the female sex character (9).
Let / represent the absence of femaleness, or the male sex character
(cf).

liCt B reprcvHcnt the factor for barring.

Ix;t b rr'pro«fMit tho aKsence of the barring factor.

Constitution of the White Leghorn Breed. 161

Employing these symbols, the zygotic formula of the Burred
Plymouth Rock cT becomes

BBff,

foniiing gametes

Bf'Bf

The zygotic formula of the 9 becomes

BbFf,
fonning gam.etes

Bf • bF

since, by hj-pothesis, B and F (or their complementary combination,
bf), cannot be present in the same gamete.

The matings occurring in the propagation of pure Barred Ply-
mouth Rock stock would therefore be represented:

cf' Bf ■ Bf X
9 Bf • bF =
9 9 BbFf, Barred
cf cf BBff, Barred
the 99 being heterozygous for barring and the cf cf homozygous.
If, however, we have the mating between the Barred Plymouth
Rock and some dark non-barred brecxl, such as the Rhode Island Red,
the case is different, and the results vary accordingly as the cf is
chosen from one breed or the other.

The zygotic formula of the R. I. Red cT (non-barreil) would be

66//,

forming gametes:

bf • hf

while the formula of the Barred Rock 9 is as showTi above. This
mating would therefore become:

cf 6/ • 6/ X

9 bF • Bf =

& & Bbff, Barred
99 66F/, Black

1G2 Bulletin No. 155.— 1913.

In other words the cf cf wouUl be barred (heterozygous) while the
99 would be black.

The reciprocal cross would be represented

& Bf' BfX
9 bF 'hS —

d" cf Bhff, Barred

9 9 BhFf, Barred

l)()th cf d^and 99 being heterozygous for barring. In other words,

all ])rogeny are barred when the cf parent is homozygous for this

character.

That Spillman's hypothesis could be verified in experimental results
was first shown by Goodale (1000) in a brief pajxT reporting the
results of matings between BufT Rocks and Barred Plymouth Rocks.
Ill a subsequent note, Goodale (1010) states that in crosses between
White Leghorn (9) and Wtiite Plymouth Rock (cf), <>nly white
l)irds appeared in Fi; in a f(^w of the.se faint bars developed. In
F2» however, there were white, black, gray and barred chicks, the
latter resembling exactly the Barred Plymouth Rocks.

In addition to the instances of barring mentioned above, Pearl
(1012) has reported, upon the authority of an English fancier*, the
liistor}' of the "Cuckoo Pekins." This bantam breed, according to
the authority cited, was produced from a mating of Black Pekin (cf)
with White Booted (9). One of the 9 progeny showed "stone-
colored bars on a milk-white ground." This bird was mated back to
its sire, tne Black Pekin. The cuckoo pullets from this mating were
mated with a cuckoo cockerel derived from imported Chinese Cuckoo
stock. Inbreeding was practical until a pennanent cuckoo variety
was established. Regarding the origin of this barred pattern, Pearl
assumes that it did not arise de novo, but that the barred factor was
]iresent in the White Booted parent. However this may be, one
further point is of interest, namely, the question of the alleged trans-
mission of barring from the White Boot<jd 9 to her daughter. As

♦Ntr. William F. Kntwisle, who has published the account in his book. "Bantams," Wake6eld«
England, 1894 (?). p. 1-116.

Constitution of the White Leghorn Breed. 163

will be shown later, this is contrary to the established method of
inheritance of barring as it occurs in the Barred Plymouth Rock
breed; and without more convincing evidence the case does not
appear to warrant the assumption that barring of this sort is inherited
in any other manner than that now generally accepted.

IIL Experimental Results.

As has been stated, at the outset of this investigation barring was
tentatively regarded as a heterozygous condition resulting from the
mating of black with white fowls. Therefore the preliminary experi-
ment involved chiefly the mating of these breeds with the aim of
securing from some of the crosses a certain number of individuals
possessing the barred color-pattern. These crosses were between the
White Leghorn cT and the following black 99: White-faced Black
Spanish, Black Minorca, Black Langshan, Black Java, Black Ham-
burg and Black Cochin. The Fi generation was bred in 1910. In
1911, the Fi breeding was continued and in atldition a number of the
F2 generation from some of the crosses were reared. In 1912, a
greater number of the F2 generation were reared, and also a number of
other crosses were made between selected F2 stock and several other
varieties of fowl. It may be said in passing that all the stock used
in the experiments was carefully selected from reputable breeders
and was probably as pure-bred as any that could be obtained in the
country. The breeds mentioned were chosen for the experiments
first of all, because so far as could be ascertained from poultry
literature none of them was known to be related to breeds possessing
the barred color-pattern such as the Barred Plymouth Rocks or the
Dominiques. The modern White Leghorn, though differing consider-
ably from the older type, is usually stated to be a breed which has
been mixed with others only to a slight extent; and it is therefore
commonly regarded as ''one of our purest breeds." As will be
demonstrated later this conception is rather doubtful. So much
regarding race-purity is not usually said of the Black Hamburgs,

164 Bulletin No. 155.— 1913.

Black Minorcas, Black Javas, Black Cochins, and Black Langshans,
although the Black Spanish breed has probably been kept fairly
pure. In no case, however, is it positive^ knowTi that barred stock
has entered into the formation of these breeds. It was therefore at
first assumed that the appearance of barring in the progeny from these
birds would indicate that this pattern had been formed de novo as a
heterozygous condition, or that it w^as inlierited from the white stock
in which it existed as a cryptomere as in the case of the White PI3'-
mouth Rock breed. Whether this was a justifiable assumption will
appear in the course of the experiments now to be described.*

Case 1. — White Leghorn c^ X Black Hamburg 9- Nature of
mating: CCBBffll X CCbbFfii. (For discussion, see p. 186).

White Leghorn cf 193A: Weight 53 2 ibs., back of medium
length; squirrel tail; body medium length, high on legs; high
comb with six points, slightly thumb-marked and blade defi-
cient in size; head long, eyes red; ear-lobes white but spotted
with red; wattles of medium size with one fold in each; neck
white with tendency to cream; back white; shanks, toes and
beak pale yellow; spurs about one inch in length; no pattern
observable on any of the feathers, which are also free from
black ticking. (See PI. I).

Black Hajnburg 9 , 1S5A'\: Weight 4^ lbs., neck of good
length; back long; tail carried high; body long but not deep;
comb of good size, rather flat on top, spike with marked u])-turn
at rear; eyes dark hazel; ear-lobes bluish white and about
half red; wattles very small, fine texture, smooth. Feathers
of neck greenish black with purple barring; primaries dull
black, secondaries and main tail feathers greenish black with
some purple barring; bodj- dull black; shanks dark slate; spurs
about J inch long. (See PI. III).

The data on the first set of W. L. X B. H. matings are summarized
in the following table :

*It will be convenient to include in the present section only the actual experimental results. All
discussion of the significance of these result.s, together with their explanation, is taken up in Section
IV, p. 182.

tBlack Hamburg 186A resembled 185A in nearly all points.

Constitution of the White Leghorn Breed.

165

Table 1. — Showing the results in Fi of crossing White Leghorn cf X Black
Hamburg 9 9 (1910 series.)

Parents.

Progeny.

Mating Number.

d^

9

White.

Black.

With barred
feathers.

201

202

193 A
193 A
193 A

185 A

186 A

*

22

8

19

0
0
0

1 d^ 1 9

211

2 c^d^

♦Female not identified, but one or the other of the above.

The data presented in Table 1 demonstrate that the white of the
W. L. in all instances dominated over the black of the B. H. The
progeny were not all pure w^hite, however, since more than one-half
of the Fi generation ( cf cf and 9 9 equally) showed black flecks
in the white feathers. When the chicks were in down-feather the
majority revealed one or more patches of black down on head, back
or sides. Table 1 also shows that of the 49 birds recorded, 4 possessed
one or more barred feathers, w^hich were usually located on the back
or among the wing coverts. In these cases the barring was usually
clear and definite, although the pattern never reached to the base of
the feather and frequently covered only the tip. No bird in Fi was
found to possess more than two or three such barred feathers. Of
the four birds so characterized, three were cf cf and one was a 9 *
In addition it should be noted that one bird showed a buff half-moon-
shaped splash at the tip of one of the saddle-feathers.

Subsequent to making the series of crosses mentioned above, a
second series was obtained in 1911. In this case one of the two B. H.
99 was employed, but another W. L. d^ was used, and B. H. 99
from a different source were also introduced. The result of these
matings is shown in Table 2.

2

166

Bulletin No. 155.— 1913.

Table 2. — Showing the results in Fi of the second series of White Leghorn X
Black Hamburg matings (Series of 1911).

Parents.

Progeny.

Mating Number.

d^

99

White

Black

With barred feathers.*

d^

99

?

8

1 A
1 A

4A
5A

14

4

0
0

1
0

4

1

0

9

0

10

1 A

6A

9

0

0

0

0

11

1 A

7 A

20

0

0

0

1

27

1 A

186 A

14

0

1

1

0

Totals

61

0

2

6

1

*These birds are also listed in the white column since their plumage was mainly white (see text).

From Table 2 it appears that of 61 Fi birds, all were white; but
that 9 possessed one or more barred feathers. Of these 9, 6 were
99, 2 were cf d^, and the sex of the other was not ascertained. In
this series there was about the same proportion of birds flecked with
black and these were evenly distributed between the sexes.

Case la. — [White Leghorn cf X Black Hamburg 9 ] cf X [White
Leghorn 6^ X Black Hamburg 9 ] 9 . Nature of mating: CCBbffli
X CCBbFfli. (For discussion, see p. 192).

Of the cross-bred fowls raised in 1910, d^ 2IIM2 and six 99 were
bred together in 1911.

The cockerel was hatched as a pure white bird without trace
of black down-feathering. Among the coverts of each wing
was a single feather showing a bufT-yellow bar; among the
saddle feathers were a few showing some buff.

Among the 99, 201 G was a nearly pure white bird but
showed a few splashes of black in wing coverts and saddle
feathers; 201 L was hatched with a large patch of black down

Constitution of the White Leghorn Breed.

167

feathers on the back, but became a pure white bird; 202 G
showed many black-splashed feathers on back and wings;
211 B showed a very small amount of black ticking; 211 K
was a pure white bird; 211 V showed a small amount of black
ticking.

Table 3. — Showing the results obtained in F2 from the mating of White
Leghorn X Black Hamburg cross-breds (1911 series).

99

Total
progeny.

White.

Black.

Barred.

Mating No.

d^

9

?

&

9

?

Gray.

314

201 G

30

21

0

6

0

2

0

1

0

315

201 L

22

16

0

1

0

2

0

3

0

316

202 G

6

5

0

1

0

0

0

0

0

317

211 B

17

15

0

1

0

0

0

1

0

340

211 K

23

18

0

0

2

0

0

0

3

341

211 V

19

15

0

0

1

0

2

0

1

Actual totals

117

90

0

9

3

4

2

5

4

Expected totals ...

87i|

7A

01 15

The data presented in Table 3 show that the F2 generation of W. L.
X B. H. cross-breds is composed of black, white, gray and barred
birds. If the gray, black and barred be considered together as
"dark" individuals, it is then apparent that this group represents
about one-fourth of the total number of fowls, while the group of
white birds represents about three-fourths. This result is what we
should expect in case of a pair of allelomorphic characters. It is
evident that the white birds, although all appearing alike, include
two sorts, — pure dominants (white), and birds that are heterozygous
for black (usually flecked) .

In 1912, another Fi d", 8 L, was mated with 12 Fi 99. Both cT"
and 99 resembled closely those used in the 1911 series of matings.

168

Bulletin No. 155.— 1913.

Table 4.— Showing the results obtained in F2 from the mating of White Leg-
horn X Black Hamburg cross-breds (1912 series).

Black.

Barred.

99

Progeny .
(Total).

White.

Mating No.

1
1

1

&

9

?

&

9

?

456

8 B, G, H, I

18

13

0

1

0

2

1

1

457

9C

13

8

0

1

0

3

0

1

458

10 H, I

14

10

0

1

0

2

1

0

459

11 B, E, G

25

21

0

0

0

2

1

1

460

201G, L

67

54

0

3

1

5

3

1

Actual totals . . .

137

106

0

6

1

14

6 4

Expected totals

i

102]^

0 '

8A

17/6

8^....

It is further apparent in Table 4 that among the ''dark" birds,
the blacks (including the grays) and barred birds appeared in tlie
ratio 7 : 24. It should be said here, however, that several of tiie
chicks which are recorded as black were described when they WTre
in down-feather. It is certain that had they lived barring would
have appeared in some of them, and the ratio of barred to black
birds would have been changed somewhat in favor of the barred
group.

There was a marked variation in the amount of barring present
in the barred individuals. The pattern invariably found clearest
expression in the hackle feathers, Aving coverts and tail coverts; the
primaries always showed a barring that was inferior to that of the
secondaries. It was also observed that the ground-color of the
feathers was not so light as in the case of feathers from a Barred
Plymouth Rock, but contained more gray or blue-gray, so that the
pattern was less distinct. But aside from these differences the type
of barred pattern observed in F2 differed in no important respect

Constitution of the White Leghorn Breed. 169

from that present in the Barred Plymouth Rocks. It corresponded
well with the barring depicted in early illustrations (see Pearl, 1911,
p. 306) of the Barred Plymouth Rock breed as it existed years ago,
before it had been developed to the present state of perfection.

As has been stated, it is impossible to ascertain when chicks are in
the down whether they may later develop barring. For this reason
the ratio of black to barred birds as expressed in Table 3 probably
does not represent the actual ratio. In order to avoid this source of
error, there was made in 1912 a second series of crosses between Fi
W. L. X B. H. stock, reared in 1911 from new birds not employed in
the 1910 matings. In compiling the records of these F2 individuals
no bird that was less than 3 weeks of age was entered. This precau-
tion made it possible to discriminate carefully between black and
barred birds, and results in some difference in the totals.

The results of this series of matings (Table 4) were essentially the
same as in the 1911 series, save in the black : barred ratio. The
barred birds showed the same sort of barring and all circumstances
indicated that the appearance of this character in F2 was in accord-
ance with some definite law. This point is discussed in detail on
p. 193, and we may now turn our attention to the results of other
crosses involving the W. L. stock.

Case 2. — White Leghorn d^ X Black Spanish 9 . Nature of mating:
CCBBffll X CCbhFfii. (For discussion, see p. 186).

In this series of matings the results of the 1910 and 1911 breeding
are combined. In 1910, W. L. 193 A was employed; in 1911, W. L.
1 A.* In the 1910 matings. Black Spanish 99 181 A and 182 A
were employed.! In 1911 B. S. 99 13 A, B and C were used.f
The Black Spanish 9 181 A, typical of the others, was described as
follows :

♦Obtained from Charles J. Fogg, Waltham, Mass.

tObtained from the Groesbeck Poultry Farms, Hartford, Conn.

JObtained from M. H. Lindsey, Northville, N. Y.

170

Bulletin No. 155. — 1913.

Black Spanish 9 , 181 A: Weight 4 ^^ lbs., neck long, back
of medium length; body of medium length, set well on legs;
comb upright, four points, fine texture; head long and face
deficient in white; eyes dark hazel; wattles are smooth and
have a fine texture; wing coverts, back and tail coverts black
with purple barring; primaries, secondaries and main tail
feathers are dull black; body feathering has a dark brown cast;
under-color dark slate.

Table 5. — Showing the results in Fi of ^Miite Leghorn X Black Spanish mat-
ings (1910 and 1911 series).

Mating No.

cfc^

99

Total
progeny.

White

With barred
feathers.

197

193 A
193 A

181 A

182 A

10
24

10
24

0

198

0

14

1 A

13 A

18

18

1 9

15

1 A

13 B

1

1

1 c^

16

1 A

13 C

6

6

1 d^

Actual total

59

59

3

A glance at Table 5 makes it evident that the white of the W. L.
dominated over the black of the B. S. as it did over the black of the
B. H. The dominance was not perfect, however, since a small
nimiber of birds showed black fleckings; and three possessed feathers
which were distinctly barred. These barred feathers appeared as
follows: In one case two right secondaries and one tail feather had
a single gray band across the tip. These barred secondaries remained
in the adult plumage, but the barred tail feather was lost. In the
second case the barred pattern w^as faintly present in one of the
saddle feathers. In the third case a bird put up one barred wing
covert which was moulted and never replaced.

Case 2a. — [White Leghorn d^ X Black Spanish 9 ] cf X [White
Leghorn cf X Black Spanish 9] 9- Nature of mating: CCBbffli
X CCBhFfli. (For discussion, see p. 193).

Constitution of the White Leghorn Breed.

171

In 1911 one of the cross-bred d^ d^ (198 B) was bred to five of the
cross-bred 99 (197 K, 198 E, 197 A, 197 G and 198 A). The cf
198 B was white except for a very faint ticking of black on a few
feathers. The 5 99 resembled the cT in all points of plumage.
In 1912, the same c^ was mated to 3 of the 1910 cross-breds and
to 3 of the Fi cross-bred 9 9, produced in the 1911 matings between
W. L. and B. S. stock. The results of these matings are presented
in Tables 6 and 7.

Table 6. — Showing the results obtained in Fo from the mating of White Leg-
horn X Black Spanish cross-breds (1911 series).

Black.

Barred.

<f

99

Total
progeny.

White.

Mating No.

Gray.

cf

9

?

o^

9

?

19

198 B

197 K

11

10

0

1

0

0

0

0

0

311

198 B

198 E

28

22

0

2

0

3

0

0

1

310

198 B

197 A

23

19

0

2

0

0

0

0

2

20

198 B

197 G

16

13

0

2

0

0

1

0

0

21

198 B

198 A

12

11

0

0

0

0

0

1

0

Actual totals

90

75

0

7

0

3 1

1

8

Expected tota

Is.

67A

0

5H

11 A 54-#

In 1912, similar matings between W. L. X B. S. cross-breds were
made with the results shown in Table 7. Combined results for the
two years are given in Table 8.

172

Bulletin No. 155—1913.

Table 7. — Showing the results obtained in F2 from the mating of White Leg-
horn X Black Spanish cross-breds (1912 series).

c^

99

Total
progeny.

White.

Black.

Barred.

Mating No.

d^

9

?

cf

9

?

Gray.

467 198 B

468 198 B

469 198 B

14 D, S, T

197 A, G

198 E

85
65
41

69
61
31

0 6
0' 4
0' 3

2
0

0

7 1 |0
0 0 0

4 0 0

1

0
0
3

Actual totals

191

161

Oi 13

2

11

i!o

3

Expected tota

Is

143 A

■
0 11^

23ft 1 1 ^

xo

— iO

Table 8. — Combined results from Tables 6 and 7.

Total
progeny.

White.

Black.

Barred.

Series.

cf

9

?

&

9

?

Gray.

1911

90
191

75

161

0
C

7
13

0
2

1
3 ' 1

1
0

3

1912

11

1

3

Actual totals

281

236

0

20

2

14

2

1

6

Expected totals

210U

0

17A

....

35x'6

17A

We thus observe from the results presented in Tables 6, 7 and 8
that barred birds made their appearance in the F2 generation of the
W. L. X B. S. cross. The fairly wide departure from the expected
ratios will be discussed on a later page.

Case 3. — White Leghorn d^ X Black Minorca 9 . Nature of
mating: CCBBffll X CCbbFfii. (For discussion, see p. 186).

Constitution of the White Leghorn Breed.

173

The cf used in this experiment was 193 A, previously described.

Black Minorca 9 , 183 A: Weight 6^ lbs., neck flat, back
of good length; body of medium length; comb, large with
serrated blade, five points, — falls half on each side; eyes light
hazel; ear-lobes bluish white, mottled with red; wattles of
fine texture, small; wing-coverts and tail-coverts greenish
with purple barring; primaries, secondaries and main tail
feathers are dull black; body feathers are very dark brown;
under-color slate; shanks are dark slate. Black Minorca 9
184 A was similar in all important respects to 183 A.

As a result of this cross all the Fi birds were white. Many showed
black tickings and one d^ put up a barred feather. This bird was
hatched as a white chick with a small patch of black down on the
back. Later a buffy tinge developed over some of the wing coverts.

Case Ssi.— [White Leghorn d" X Black Minorca 9 ] d" X [White
Leghorn d" X Black Minorca 9] 9- Nature of mating: CcBbffli
X CcBhFfli. (For discussion, see p. 193).

Of the W. L. X B. M. cross-breds raised in 1910, cf 200 C, which
put up one barred feather the first year, was mated in 1911 with two
of his sisters, 199 E and 200 D. These two 99 were white but
showed many feathers that were ticked with black. The results of
this cross are presented in Table 9.

Table 9.— Showing the results obtained in F2 from the mating of White Leg-
horn X Black Minorca cross-breds.

d"

99

Total
progeny.

White.

Black.

Barred.

Mating No.

cT 9

?

1
0

C
1

9 ?

312

^13

200 C
200 C

199 E

200 D

10

7

9
5

olo

0 1

0
0

0
0

Actual totals

17 14

0 1

1

j

1

1

■^16

0

0

Expected totals

12 Jl

ll^-..

174

Bulletin No. 155. — 1913.

From the data presented in Table 9 it is apparent that, as was the
case with the W. L. X B. H. and the W. L. X B. S. cross-breds,
here also we have both black and barred birds thrown out in F2.
But, whereas in the earlier matings the dark : light ratio came very
close to Mendehan expectations, in the present case the departure
is more noticeable. It is probable, however, that observation of a
larger number of birds would have yielded results closer to the
expected.

The one barred bird resulting from this cross, 313 C, was a cf . Its
general coloration was gray but barring was well manifested in
feathers of the hackle and back and in the wing coverts. No barring
was present in the primaries but it could be distinguished faintly in
the secondaries.

Case 3b. — [White Leghorn cf X Black Minorca 9 ] c^ X Black
Minorca 9. Nature of mating: CcBbffli X CCbbFfii. (For dis-
cussion, see p. 194).

In addition to the foregoing, the results of a cross between an
Fi cf and pure-bred. Black Minorca 99 may be reported. The
cf 200 C as previously stated showed on the right flank a feather
barred over one-half. The B. M. 99 were those used in the Ft
matings. In Table 10 are presented the data relative to this back-
cross.

Table 10. — Showing the results of the cross: [White Leghorn cf X Black
Minorca 9 ] cf X Black Minorca 9 .

Mating No.

c^

99

Total
progeny.

White.

Black.

Barred.

cf

9

cf

9

325

200 c
200 c

183 A

184 A

5
1

3
0

0
0

1
1

1
0

0

326

0

Actual totals

6

3

0

2

1

0

Expected totals

3

H

H

H

H

Constitution of the White Leghorn Breed.

175

In Table 10 it is shown that of 6 birds resulting from this cross 2
were black 9 9 and one was a barred cf . The latter developed into
a well barred adult bird (325 B). The pattern was clearest in wing
coverts, tail coverts and hackle feathers. On the primaries barring.
was faint but clearer on the secondaries. The general coloration was
slightly brownish.

Case 3c.

I [White Leqhorn cf X Black Minorca 9 ] cf
•cf -i _. I X

Black Minorca 9

Black Minorca 9- Nature of mating: CCBhffii X CCbbFfii,
(For discussion, see p. 195).

In case the barred, cross-bred cockerel, 325 B, possessed the
barred character in heterozygous condition (as represented in the
zygotic formula CCffBhii) it is to be expected that, when mated with
pure Black Minorcas, one-half of his progeny would be barred. In
the season of 1912 this mating was made with the results presented
in Table 11.

Table 11. — Showing the results obtained from the cross indicated above.

cT

99

Total
progeny.

Black.

Barred.

Mating No.

d^ 9

?

c^

9

?

472

473

325 B
325 B

184 A
34 A, B

13
53

4
12

2
13

0
3

4
9

3

12

0

4

Actual totals

66

16 15

3

13

15

4

Expected totals

16K 161^

163^

16K

The results of this cross demonstrate that the mating of the barred
cf, 325 B, with the pure-bred Black Minorca 99 gave one-half
barred and one-half black progeny; and that the barred and black
birds were about equally divided between the sexes.

176

Bulletin No. 155. — 1913.

Case 3d.— cT

[white Leghorn d^ X Black Minorca 9 ] cT

X

Black Minorca 9
9 [White Leghorn cT X Black Minorca 9 ]• Nature of mating:
CCBhffii X CCBbFfli. (For discussion, see p. 196).

In this instance, the barred cross-bred cockerel, 325 B, was bred
to one of the 99 which resulted from the first W. L. X B. M. cross.
The results are presented in Table 12.

Table 12. — Showing the results of the mating indicated above.

Mating No.

d^

9

Total
i:)rogeny.

White.

Black.

Barred.

c^

9

?

cf

9

?

474

325 B

200 D

34

17

1

1

2

7

2

4

Expected totals. . . .

17

C

4K

81

4i

In Table 12 it is shown that one-half of the progem' of 325 B were
dark and one-half light. Of the darks one-fourth were black and
three-fourths barred.

[White Leghorn cf X Black Minorca 91 cf

CASE3e.— d^ \ — X

Black Minorca 9 J

[ {White Leghorn d" X Black Minorca 9 ) cf ^

9 \ r Nature of mating:

[ Black Minorca 9 |

CCBhffii X CCbbFfii, black, and CCbbFfli, white, or CCBbFfli,

white. (For discussion, see p. 198).

In this case the barred cross-bred d^, 325 B, was mated vdth two
of his sisters, 325 A and 325 E. Female 325 A was clear black with
blue-black beak and shanks and a slight green tinge to the plumage.
Female 325 E was a white bird with light shanks and beak. The
results of these matings are given in Table 13.

Constitution of the White Leghorn Breed.

177

Table 13. — Showing the results of the crosses indicated above.

c?

99

Total
progeny.

White.

Black.

Barred.

Mating No.

&

9

?

&

9

?

470

325 B

325 A

(black)

43

0

6

8

4

10

12

3

Expected. .

0

10% lOM

lOM lOM

Totals.

21 J^

2iy2

471

325 B

325 E

(white)

50

■[ 25

2

6

5

5

4

3

Expected* .

25

QH

6K...

QH

6M

»..

Totals.

12^

123^

♦Provided the zygotic constitution of the 9 325 E is CCbbFfli.

From the data presented in Table 13 it is apparent that in the
mating of 325 B with his black sister, 325 A, there was a tendency
to produce equal numbers of black and barred progeny ; and that the
sex-ratio between these groups approximated 1:1.

In the mating of 325 B with his white sister, 325 E, half the
progeny were white, while the other half included both black and
barred birds in equal numbers and equally divided between the
sexes.

(White Leghorn cf X Black Minorca 9 ) cf

Case 3f.— d^ \ ^ X

[ Black Minorca 9 J

Black Java 9 . Nature of mating: CCBbffii X CChbFfii. (For

discussion, see Case 5, p. 203).

Among the self-colored birds with which the barred cross-bred cf
325 B, was mated during the season of 1912 were the Black Java 99
335 C and F. The results of this mating are given in Table 14.

178

Bulletin No. 155.— 1913.

Table 14. — Showing the results of the mating indicated above.

Mating No.

cT

99

Total
progeny.

Black.

Barred.

d"

9

cf

9

?

477

325 B

335 C, F

52

11

16

10

14

1

Expected totals

13

13

13

13

Expected grand totals.

26

26

From the data presented in Table 14 it is clear that one-half of the
progeny from this cross were black and one-half were barred; and
that the black and the barred birds were about equall}^ divided
between the sexes. Similar results were obtained from mating the
cross-bred d^, 325 B, ^\ith Black Hamburg 99. One of the cTcf,
477 V, resulting from the Black Java cross, was mated in 1913 with a
pen of barred 99. This mating is considered in Case 5, p. 203.

Case 4. — White Leghorn d^ X BJacJ: Java 9 . Nature of mating:
CCBBffll X CChbFfii. (For discussion, see p. 186).

In other series of crosses bred in 1911, 1912 and 1913, the W. L. d^,

193 A, used in the previous experiments, was mated with several

B.J. 99.

Black Java 9, 187 A: Weight 7| lbs., good form but
shghtly lacking in breast; beak black shading into yellow at
base; eyes hazel; ear-lobes are three-fourths white; wattles
red; small amount of purple barring on feathers of neck, wing
coverts and tail coverts; primaries, secondaries and main tail
feathers are dull black; under-color dark slate; shanks and
feet yellow. The other Black .lava 9 9, 188 A, 230 A and
231 A, resembled the bird described above in all important
points.

The result of this series of matings shows that as in earlier cases the
white of the W. L. was dominant over the black of the Java; fur-

Constitution of the White Leghorn Breed.

179

ther, that as in other crosses, birds possessing a few barred feathers
appeared in Fi. Of these birds two were cf cT in which the barred
pattern appeared in the coverts or saddle feathers.

Case 4a. — [White Leghorn cT X Black Java 9 ] cf X [White Leg-
horn cf X Black Java 9] 9. Nature of mating: CcBbffli X
CcBhFfli. (For discussion, see p. 193).

In the season of 1912 the cross-bred cf 25 C was mated with cross-
bred 99 of similar constitution. The cockerel was a solid white
bird except for one feather in the middle of the back which showed
barring on one-half. Of the 99 used, 25 B showed at the age of
one month slight barring in the right secondary coverts and in two
secondaries. At the age of five months the barring had disappeared.
Female 25 I showed a few dark saddle feathers but no barring.
Female 203 B was a pure white bird.

Table 15. — Showing the results in Fj of the White Leghorn X Black Java,
cross-breds (1912 series).

Mating No.

d^

99

Total
progeny.

White.

Black,

Barred.

cf

9

?

cf

9

?

481

482

483

25 C
25 C
25 C

25 B

25 1

203 B

33
38
44

26

27
38

0
0
0

1
3
2

0
0

1

2
5
1

1

2
2

3
1
0

Actual totals

115

91

0

6 1

8 5

4

Expected totals

86 r\

0

7ft...

14ft 7ft

Expected grand total

s

86 1^

7A

21 A

In 1912 other crosses between W. L. aid B. J. stock were made.
These involved the use of W. L. cf , 1 A. As expected, the first

180

Bulletin No. 155.— 1913.

generation, raised in 1912, was composed entirely of white birds-
The results in F2 (1913) are shown in Table 16.

Table 16. — Showing the results in F2 from the matmg of White Leghorn X
Black Java eross-breds (1913 series).

Mating No.

c^

99 ' Total

progeny, t

White.

Black. t Barred.*

5.53

463 A

463 E, F, J 30

18

3 9

554

463A464K, X, Q 47

37

2 8

Actual totals

II

55

5 17

Expected totals . . .

57 n

4^ Hi%

*The sex of the black and the barred birds could not be ascertained in time to report in this
publication.

tOver 3 weeks old when described.

The data presented in Table 16 indicate that in F2 of the cross
under discussion, white, barred and black birds appeared in the
ratio 55 : 17 : 5.

(White Leghorn cf X Black Minorca 9 ) cf

Black Minorca 9 \ X

Case 5. — d^ <

9 Black Java

Cross-bred 99, heterozygous for barring . Nature of mating: CCBbffii
X CCBbFfii. (For discussion, see p. 203).

Male 477 V was a fairly well-barred bird but with dark under-color.
The general tone had a brownish tinge. The 9 9 mated with him
had the ancestry given below:

cf [Wh. Leqhorn cf X Blk. Hamburg 9 ]

461 E.— r^

{Wh. Leghorn cf X Blk. Hamburg 9 ) cf

iWh. Leghorn cf X Blk. Hamb. 9 ) 9
343 B, E. — Out of mating given in Case 3e; from black 9 •

Constitution of the White Leghorn Breed.

181

344 B. — Out of mating given in Case 3e; from white 9 .

(White Leghorn cf X Black Minorca 9 ) cf
472 E. { d^ \

Black Minorca 9

473 F.

474 G.—

c^i

9 Black Minorca.
j (White Leghorn cf X Black Minorca 9 ) cf

Black Minorca 9

476 A.—

&

9 (White Leghorn d^ X Black Minorca 9 )
(White Leghorn cf X Black Minorca 9 ) cf 1

Black Minorca 9

9 Black Hamburg

477 E, P, S.— Same ancestry as 477 V.

The results of these matings, which were made in the season of
1913, are presented in Table 17.

Table 17. — Showing the results obtained from the matings described above.

Mating No.

541

542.

543

544.

545.

546.

547.

548.

549.

550.

551.

552.

Parents.

a'

99

477 V

461 E

477 V

343 B

477 V

343 E

477 V

344 B

477 V

472 E

477 V

473 F

477 V

474 G

477 V

476 A

477 V

477 E

477 V

477 P

477 V

477 S

477 V

347 E

Total
progeny.

<

40
17
14

2
10
29

1
27
33
30
27
17

15
6
3
0
4

10
0
7

13
7
5
5

25

11

11

2

6

19

1

20

20

23

22

12

Actual totals .

247

172

Expected totals.

62

185

*Over 3 weeks old when described.
, fThe sex of the black and the barred birds could not be ascertained in time to report in this
publication.

3

182 Bulletin No. 155.— 1913.

IV. General Discussion of Results.

The experimental data presented in the foregoing pages make it
clear that a type of barred plumage-pattern has arisen in F2 from the
mating of white with black birds. First of all we may ask : Where
did this barring, manifested in a few feathers of a small nmnber of Fi
individuals but appearing as a fully developed barred pattern in a
certain proportion of F2 progeny, have its origin? As stated at the
beginning of this paper it was tentatively assumed, when the present
investigations were planned in 1909, that barring represented a
heterozygous condition resulting from the crossing of light colored
with dark colored birds. This tentative assumption was based on
the fact that breeders* have commonly made the observation that
the crossing of Blacks X Whites occasionally gave some birds
with good barring. Thus the barred plumage-pattern was considered
by some as a mosaic made up of black and white. It is now clear,
however, that this view is not supported by any evidence supplied by
the present investigations. In Fi, contrary to expectation, the degree
of dominance of white in all the White Leghorn X Black crosses was
so great that the presence of black pigment was usuallj- manifested
only as flecks on an otherwise pure white plumage, or, in a smaller
number of cases, as a partly barred feather among the white. If the
barred pattern were of the nature of a mosaic, it should appear most
definitely in Fi; one would not be led esp)ecially to anticipate its
appearance in F2, — at least in a well developed condition. But as
shoTMi in all the tables giving data on the F2 birds this is exactly
where the most extended and most clear-cut barring did appear.

In contrast to the view outlined above, several other invest igationsf
dealing with the type of barring found in Barred Plymouth Rocks
have shown that this character as there found may behave in in-
heritance like a unit-character; it is separately heritable. In other
words, birds that show this barred pattern may be assimied to possess
the factor for barring; and without the presence of this factor in the

♦See Davenport (1906); Wright (1905); Hurst (1905).
tGoodale (1909); Pearl and Surface (1910).

Constitution of the White Leghorn Breed. 183

zygote, barring cannot appear. Thus the outcome of the first season's
breeding of black with white birds, when coupled with the evidence
of the existence of a barring factor, B, supplied by other breeders,
demanded a change in view regarding the origin of the barring in
question; at least it required a consideration of the possibility that a
factor for barring might be present in one of the parent breeds used
in the experiments.

If a factor for barring were present in any of the parent breeds it
seemed probable that it did not exist in the black 99, since experi-
ence has shown that the black pigment possessed by these birds would
cause the barring factor to be revealed even if it existed in a hetero-
zygous condition.* Hence it was assumed that it might be present
in the W. L. cf ; and it became the aim of the investigation to test this
point experimentally; furthermore to ascertain the behavior of this
type of barring in F2 and subsequent generations; also to produce,
by the breeding of selected birds possessing the requisite gametic
constitution, a barred breed, wholly distinct (at least with respect
to the origin of the barred pattern) from the Barred Plymouth Rocks.
To what extent these results have been accomplished will appear in

the following pages.

First, however, it is desirable to consider in some detail the prob-
able zygotic constitution of the black and white fowls concerned in
the experiments, since the expression of the factor for barring is
dependent as will be shown, upon the presence or absence of several
other factors,— especially the factors for sex and for the inhibition of
black pigmentation. We may therefore inquire, first, as to what
factors, among those with which we are especially concerned, are
present in the birds used in the matings already described^

~*For instance, it is well known that if pigment be added to the White Plymouth Rock, as a result
of mating with black breeds, the barring will be revealed in Fi.

184 Bulletin No. 155.— 1913.

It seems probable that we have to deal with at least four different
factors: (1) a factor for black pigmentation, C*, (2) a factor for the
inhibition of pigmentation, I; (3) a factor for sex (F, female; f,
male) ; and (4) a factor for barring, B.

With reference to these factors, what then is the zygotic con-
stitution of the black 99? First, we can assmiie that they are
homozygous for black pigmentation {CC)*; second, that they are
homozygous for the absence of barring (hb); further, that they are
homozygous for the absence of the inhibiting factor (ii) which factor,
in the case of the W. L., as will appear, prevents the black pigment
from showing. Finally, we will assume that they are heterozygous
for the female sex (Ff). The zygotic formula of these birds could
therefore be written C2h2Ffi2-

Making use of these symbols we may now consider the zygotic
formula for the W. L. cf • The W. L. breed of fowls is usually re-
garded as a ''pure" white variety, sometimes called the dominant
white or D-white, since in matings with dark birds the white appears
to dominate over black. But, if we regard the white plumage as an
absence of pigvicntation it is manifestly illogical to say that the absence
of a character can be dominant over its presence. Therefore another
explanation must be sought for the apparent dominance of white,
and we may assume with Bateson and Punnett {op. cit.) that the
dominance of white is due to the inhibiting factor /, which has the

*It appears from the work of Bateson and Punnett (1908) on the D-whites and the R-whites,
that black pigmentation in poultry nuiy not always be due to a single factor. There may be present
a general factor for color, C, and in addition factors for special pigmentations, such as buff, red or
black. The latter, as suggested by Davenport and others may be conceived of as partaking of the
nature of an enzyme, which, as a result of its action upon C, produces the color in question. Ac-
cording to this view the presence of both factors would be required if the bird is to show pigmenta-
tion. For instance, with reference to the inheritance of color in birds possessing two kinds of pig-
ments, wc might need to consitler three sorts of factors: the general color factor, C, and two
special color factors, which working upon C, might produce, the one red, the other black pigment.
The explanation of color-inheritance in poultry may eventually be found not even so simple as
this; but it is apparent from results already attained that, as in the case of the inheritance of certain
colors in the sweet pea, several factors may be involved. In the present ease, however, we are
concerned on the one hand, only with the presence of black pigmentation (or its potential possibility
of appearance, other factors permitting) and, on the other hand, with the apparent absence of black.
For this reason, and to avoid complexity, it will be sufficient for present considerations to assign
to the black pigmentation a single factor, and this we will term C, with the understanding that in
reality this character may be dependent upon the action of two factors instead of one. These
might be compared with the factors which Davenport (1909) calls C and X; or to factors which
Bateson and Punnett (1908) refer to as X and Y.

Constitution of the White Leghorn Breed. 185

power to repress the manifestation of black pigment in the plumage ;
and this power is still present, although lessened, when I2 is diluted
to a heterozygous condition, li, as is the case in Fi of the W. L. X
Black cross-breds.

With our recognition of the fact that the W. L. cf carries inhibiting
factors which repress the manifestation of black in the plumage of the
progeny from matings with black breeds, the results of certain matings
lead to the question whether the W. L. in its own somatic cells,
possesses the elements of black pigmentation. Without now enter-
ing into a discussion of this point, which is considered in detail on
a later page, it may be said that evidence derived from breeding
experiments yet to be presented indicates that the W. L. cf carries
in its germ cells the factor or factors for black pigmentation. This
view will be found in harmony with the experimental results already
given and with others to be mentioned subsequently.

Looking at the problem in this light the W. L. may be regarded not
as an actually white bird, but as a black one in which an inhibiting
factor prevents the black from appearing. We may then tentatively
assume that the W. L. cf is homozygous for black pigmentation, and
at the same time homozygous for the inhibiting factor. Of course,
were the W. L. d^ heterozygous for C, the visible results in Fi would
be approximately the same.

With respect to the factor for sex, assuming a Mendelian interpre-
tation of this phenomenon, we may tentatively regard the W. L. d^ as
homozygous {ff) for the absence of the female sex factor, the 9 9 as
heterozygous (Ff) for F.

We come now to the relation of the W. L. cT to the factor for
barring. If the W. L. carries barring at all, it might be assumed that
it is either homozygous {BB) or heterozygous {Bh) for this character;
and the theoretical results from crossing will vary with the possibility
which we assume to hold true. In deciding this point we may take
into consideration the probable manner of inheritance of barring in
the W. L. breed provided this breed does actually carry, more or less
regularly, the factor for the barred plumage pattern. Analogy with

186 Bulletin No. 155.— 1913.

the Barred Plymouth Rocks permits the assumption that the W. L.
d^ cf are homoz3"gous (BB) while the 9 9 are heterozygous (Bh)
for this character. This circumstance would maintain the barred
pattern under conditions of equilibrium in both sexes in successive
generations; and logically we cannot assume otherT\4se if our experi-
mental birds belong to pure-bred stock. On this assumption, the
complete zygotic formula for the W. L. c^ would be C2B2f2l2, while
that of the 9 would be CzBbFfh, since the 9 is assumed to be
heterozygous for both female sex and barring, and homozygous for the
inhibiting factor. On the basis of these assumptions (which, it must
be fully understood, are for the moment merely assumptions, used to
frame a working hypothesis) we may now turn to a more detailed
consideration of the special cases.

A. Discussion of the Special Cases.

Cases 1,2,3 and 4- — On the basis of the assmned zj^gotic formulae
previously stated, what is the expected result of crossing the \V. L. cf
with the black 99? The W. L. cf forms onl}^ one type of gamete, —
CBfl, while the black 99 form two types, CbFi and Cbfi. The
mating may then be represented

^ CBfl ' CBfl X
9 Chfi ' CbFi —

cf" d" C^BbfJi, white
9 9 C2BbFfIi, white

In other words, the first cross between the W. L. cf and the black
9 9 giyes birds that are all white and heterozygous for the barring
factor and for I. It has been stated in the description of the experi-
ments that a few Fi birds put up one or two barred or partly barred
feathers. This may be explained on the grounds that the dominance
of the inhibiting factor, /, was not complete when, as in Fi, it existed
in a heterozygous or simplex condition. Where a little black was
permitted to show, there it filled out the pattern of a barred feather.
When the black was inhibited to a still greater degree, the pigment

Constitution of the White Leghorn Breed. 187

appeared only as minute ticks on an otherwise white plumage. In
this respect no difference was observed between 6^ cf and 9 9 .
Davenport (1909) has reported that in certain crosses involving a
W. L. Bantam d^ and certain black 99 the ticking was chiefly
in the 99.

We may now compare the results of the present matings with some
similar cases reported by other investigators. First, among those
who have used the W. L. may be mentioned Davenport (1906) who
reports the following instances :

1. W. L. (Bantam) cT X Dark Brahma 9. Result: 16 white, or white
splashed; 5 black; 7 barred and 3 of the Brahma type. All of the blacks were
99, while of the barred birds, 3 were cT d^, 2 99 and 2 of unknown sex.

2. W. L. (Bantam) c^ X Black Cochin (Bantam) 9. Result: 10 white, 7
black and 7 barred.

3. Single Comb W. L. d^ X Houdan 9 . Result: Of 41 individuals, all were
white with traces of black.

In the following cases, Davenport mated various cf cT with White
Leghorn 9 9 :

4. Black-breasted Red Game Bantam cf X W. L. (Bantam) 9. Result:
Among 24 individuals were 12 dark and several barred birds.

5. Bnff Cochin Bantam cf X W. L. (Bantam) 9- Result: Among 31 off-
spring were 9 white, 9 white and buff, 4 white and black, 2 white, black and buff,
4 black and buff, and 3 black. No barred birds were reported for this cross.

6. R. C. Black Minorca d" X S. C.W. L. 9 . Results: Of 83 birds, 74 were
white and 9 were pigmented. Davenport states, however, that one of the Leg-
horns used (B) in this cross gave all the dark progeny, while the other two Leg-
horn 9 9 (A and C) gave only white.

To the above cases in which the W. L. 9 was used, Hurst (1905)
adds the following cases :

7. Houdan d X W. L. $. Results: 94 whites and 11 blacks. Of the
blacks there were 6 pure blacks (99) and 5 barred ( cT cT).

8. Black Hamburg cT X W. L. 9. Results: Of 57 individuals (in down-
feathers) 49 were white and 8 were bl&ck.

Regarding the eight instances reported by Davenport and by Hurst,
the following may be said :

Instance 1. — Davenport's W. L. Bantam cf was undoubtedly
heterozygous for both B and I. The pure-bred W. L. cT must be

188

Bulletin No. 155.— 1913.

regarded as homozygous for /. If the W. L. Bantam in question
possessed the constitution C^Bhf^Ii, one would expect in Fi equal
numbers of dark and light birds; and each sort would be equally
divided between the sexes. Of the dark birds, half should be barred
and half non-barred. The actual and the expected results can be
represented as follow^s:

Results.

White.

Black.

Barred .

Brahma.

Actual

Expected. . .

16

5

7M

7
7M

3

(?)

It is clear that, on this interpretation, there is close correspondence
between the actual and expected in Davenport's first instance, second
series {I. c, p. 37), in which the cT" parent was the W. L. Bantam

Instance 2. — In this case, Davenport's results are explainable on
the hypothesis made for Instance 1. If the constitution of the
W. L. Bantam were CiBhf^Ii, we should have the following ratios:

Results.

Total.

White.

Barred.

Black.

Actual

24

10
12

7
6

7

Expected

6

This explanation is also in accord with Davenport's results in
mating the same W. L. Bantam d^ with W. L. 99 (Davenport's
Nos. 127 and 128).

Instance 3. — The results in Fi are in full accord with the present
hypothesis. Apparently the W. L. cf was homozygous for /.

Constitution of the White Leghorn Breed. 189

Instance 4- — If we assume that the W. L. Bantam was heter-
ozygous for / and B, and that B is, in this case, a sex-hmited char-
acter, we should expect to find, among 24 individuals, 12 white and
12 dark; of the latter, 6 would be black 99 and 6 barred d^d^.
Actually Davenport obtained 12 whites, and 12 darks. Of the darks,
some (actual numbers not given) were barred and these were all d^ cf •
This explanation places Davenport's results in full accord with the
present hypothesis.

Instance 5. — The results of this mating are consistent with the
explanation furnished in this paper, and suggested in Davenport's
report {op. cit., p. 82). The only possible difference is one of inter-
pretation, in that we may regard the W. L. Bantam as heterozygous
for /, instead of "heterozygous in white" as indicated by Davenport.

Instance 6. — In the case of the 99 A and C the results are as
expected. Both birds were apparently homozygous for /. As
Davenport states, ''B's germ cells were probably mixed;" it was
doubtless heterozygous for /.

Instance 7. — From the first cross mentioned by Hurst {op. cit., p.
133) we should expect nothing but white birds. The fact that 6
blacks and 5 "cuckoos" were observed in Fi demonstrates, as sus-
pected by Hurst, the "mixed" nature of some of the stock. If, as
was the case in Davenport's Instance 4, these impure W. L. 99
were heterozygous for both I and B, then we would expect exactly
the "curious" results obtained by Hurst. The heterozygous barring
of the "mixed" 9 or 99 would be transmitted only to the c^ cf
while it is most improbable that the 9 9 could derive barring from
the Houdan d^ [C2h2f'ii2[-

Instance 8. — In Hurst's Experiment 2 {op. cit., p. 134) one would
expect all the progeny to be white, or white flecked with black. The
fact that black birds resulted from this cross indicates that some of
the W. L. 9 9 were not pure for /. The expected results are as in
Instance 7, and the fact that Hurst reports no barred cf cf is doubt-
less due to the circumstance that the 8 blacks did not live long
enough to develop barring. The sex-ratios are not reported.

190 Bulletin No. 155.— 1913.

In conclusion, it may be said regarding the above cases that the-
Fi results of both Davenport's and Hurst's matings of W. L. stock
with various black breeds are fully explainable on the hypothesis
advanced above: that the W. L. cT cf are normally homozygous
for B and /, while the 9 9 are homozygous for I but heterozygous
for B. Many of the birds used by both Davenport and Hurst were
manifestly impure with respect to several factors.

Cases la, 2a, 3a and 4a. — What now happens when the Fi cross-
breds from any of the matings presented in Cases 1, 2 and 3 are
mated among themselves? The white cross-bred cf cf as we have
seen possess the zygotic constitution

C2Bbf2li
while the 9 cross-breds are

C2BhFfIi
The cf forms gametes,

CBfl ' CBfi • Chil ' Chfi
Since the 9 is heterozygous for three pairs of characters, eight
sorts of gametes might be expected :

CBfl • CBFI ' ChFI • CBFi

CBfi • Cbfl • CbFi ' Chfi
But it has been pointed out on a previous page that in the case of
the Barred Plymouth Rocks there is good reason for assuming that
the factors B and F never pass together into the same gamete; that
there is some sort of a repulsion between these factors. In tlie case
of the Barred Plymouth Rocks this results in black, or at least non-
barred 99 when B. P. R. 99 are crossed by the cf of a non-
barred breed. Since we have observed in the data already presented
a certain proportion of black 99 are produced in F2, we may
tentatively assume that in the White X Black crosses being described
there exists a similar incompatibility between the factors, B and F,
It may therefore be supposed that of the 8 sorts of gametes that might
be formed by the 9 cross-bred (with the zygotic formula, CiBbFfli)^
there are actually formed only four; in other words, we may eliminate
from consideration all possible gametic combinations containing both

Constitution of the White Leghorn Breed.

191

B and F, together with their complementary gametic combinations.
Looking at the matter in this Ught we have formed by the cross-bred
9 9 only the following gametes :

CBU ' ChFi ' CBfi ' ChFI

The mating between the Fi cf and the Fi 99 may therefore be-
represented as f ollow^s :

d^ CBfl • Chfi ' CBfi • Cbfl X
9 CBfi • ChFi • CBfi • CbFI =

02^2/2/2 (1), white

C2Bbf2l2 (1), "

C^Bhfdi (2), "

C 2^4211 (2), "
C2Bhj2ii (1), barred
I C.SsM (1), ''

c^cr"

99

' C2BhFfl2 (1), white

C262F/72 (1), "

C2BhFfIi(2), "

C2h2FfIi (2), ''

C2b2Ffi2 (1), black
[ C2BhFfi2 (1), barred

The data presented above may be summarized as follows :

Character.

d^

9

Total.

White

1
6
0
2

6
1

1

12

Black

1

Barred

3

Totals

8

8

16

In other words, among every 16 birds in F2 we may expect 12
whites, 3 barred and one black. The whites should be equally

192 Bulletin No. 155.— 1913.

divided between the sexes ; 2 of the three barred birds should be cf cf
and all black birds should be 99; moreover, one of the barred
males should be homozygous for the barring factor while the other
cT" and the 9 should be heterozygous. Other birds both d^ and 9
carry the barring factor but do not visibly manifest the barred pattern
because they are either homozygous or heterozygous for I, — a cir-
cumstance which prevents the appearance of the pigment and there-
fore of the barring also.

Having thus outhned the expected results in the Fo generation
from White X Black crosses, provided the White Leghorn d^ was
actually homozygous for barring and actually possessed the in-
hibiting factor /, we may now attempt to ascertain to what extent
these theoretical results agree ^vith the experimental data and
furnish an interpretation for them.

Case la. — White Leghorn X Black Hamburg, Fo. — (Tables 3 and 4,
pp. 167 and 168). First of all it is apparent that the ratio 3 white:
one dark is closely reaUzed among the 117 birds included in Table
3 and in the 137 birds comprising Table 4. In the 1911 series
(Table 3) the actual results were 90 white : 27 dark, and the expected
results 88 : 29. Whereas we should expect only 7 + blacks (all
females) we actually have 12 (16 including the grays), including 9
99 and 3 in which the sex was not ascertained. In explanation of
this discrepancy it may be said that in young chicks under 2 weeks
of age, it is difficult to distinguish accurately the blacks from the
barred. In case chicks die during the first week or two, all those
which might later develop barring must be described as black.
There can therefore be no doubt that several of the birds described
as black would have become barred if they had lived. The only way
seen at present to avoid this difficulty is to embod}' in the tables no
chicks which die when less than 3 weeks of age. This plan was
adhered to in the formulation of Table 4.

Regarding the barred birds, it is clear that more are called for
(21-|-) than actually appeared (11); but as already explained, the
•deficiency would probably have been made up by addition of the

Constitution of the White Leghorn Breed. 193

individuals from the "black" column, if these had lived long enough
to develop their barring. It is apparent, however, that the ratio of
cT cf to 9 9 is in the right sense.

Turning now to the results of similar matings presented in Table 4,
it is apparent that the experimental results conform more closely
to the expected. In this case all the chicks were over three weeks
old when described. The obtained ratio of whites to blacks is
106 : 31, while the expected is 102 : 35. The actual ratio of black
to barred birds was 7 : 24, while the expected was 8+ : 25+. As
was to be expected no black cf cf appeared while the number of
barred d^ 6^ was approximately twice the number of the barred
99 (14:6), the expected being 17+ : 8+.

It is thus clear that when only chicks over three weeks old are
included in the tables the actual and the expected ratios find close
agreement, and appear to demonstrate the correctness of the view
that the cf W. L. is homozygous for the barred plumage pattern.

Case 2a. — White Leghorn X Black Spanish, Fo. — (Tables 6, 7
and 8, pp. 171 and 172). The 1911 results presented in Table 6 show
a predominance of whites and a deficiency of both black and barred
birds. These matings were repeated in 1912 to ascertain whether
the same defective ratios were present. Table 7 makes it appear that
both the excess of whites and deficiency of dark are still apparent^
although in the case of the progeny of 14 D, S and T* the experimental
results are closer to the expected. What circumstance causes the
defective ratios shown in the totals in Table 9, cannot at present be
stated. In this instance, some unsuspected factor msiy be at work.

Case 3a. — White Leghorn X Black Minorca, Fo. — (Table 9,
p. 173). Although only a small number of individuals were raised
from this mating, the experimental results, as in the case of W. L.
X B. H., F2, are seen to correspond well with the expected.

Case 4a. — White Leghorn X Black Java, F2. — (Tables 15, 16, p.
179, 180). There is seen in the 1912 cross-breds a slight deficiency in

*These 9 9 were raised from the Black Spanish mothers of F^ in the season of 1911.

194

Bulletin No. 155. — 1913.

the white and in the barred birds. But the ratios have an approxi-
mate agreement and the sex-ratios are all in the expected sense. In
Table 15, showing the F2 results of the 1913 series, it appears that
the experimental results come very close to the expected.

Case 3b. — {White Leghorn X Black Minorca) d^ X Black Min-
orca 9. (Table 10, p. 174). It has been shown in Table 10 that
when the White Leghorn X Black Minorca Fi d^ was bred back to
pure Black Minorca 99, the offspring included white, black and
barred birds. We may now submit this case to Mendelian analysis,
making use of the same factors as those employed in the discussion of
F2. Assuming the zygotic formula of the Fi cross-bred cf to be
C^Bhf^Ii, and that of the black 9 to be C2h2Ffi2, the mating may be
represented :

& CBfl • Cbfi • CBfi • Cbfl X
9 CbFi ' Cbfi =

c^d^ {

C2Bbf2li, white
0262^2^2, black
C2Bbf2i2, barred
C2b2f2li, white

99

CiBbFfli, white
C2b2Ffi2, black
C2BbFfi2, barred
C2b2FfIi, white

Thus, according to the present hypothesis, there would appear in
F2, in every lot of 8 birds, the following types :

Character.

d^

9

Total.

White

2

1
1

2

1
1

4

Black

2

Barred

2

Total

4

4

8

Case 3c. d^ -^ • '- r: — r~rT. r X Black

Constitution of the White Leghoen Breed. 195

Now how do the observed results compare with the expected? In
Table 10 (p. 174), have been presented the experimental results which
should test the present theory. It is there shown that of 6 birds
half were white and half dark; of the darks two were black and one
was barred. The number of individuals described is too small to
be of great value but it appears that the trend of the data is towards
the verification of tlie hypothesis which has been assumed to cover
these cases.

( [White Leghorn d^ X Black Minorca 9 ] cf
Black Minorca 9

Minorca 9 • — (Table 11, p. 175). Under the heading of Case 3b
(Table 10) it has been shown that the mating (W. L. X B. M.) cT
[C2Bhf2li] X Black Minorca 9 [C2h2Ffi2] gives one-eighth d^ d^ that
are heterozygous for barring and lack the black-inhibiting factor I.
Using as a breeding unit a d^ having the zygotic constitution C2Bhf2i2,
it should be possible, if the theoretical deductions are correct, to build
up a group of barred 9 9 possessing the barring originally derived
from the W. L. d^ . The first step in this process would be to demon-
strate that d^ 325B actually was heterozygous for the barring factor,
and would transmit this character to his offspring; then to produce
heterozygous 99, free from I, and a homozygous d^ possessing the
zygotic formula C2B2f2i2, — in other words, the constitution of the
pure-bred B. P. R. d^ . To accomplish the first step mentioned above
d^ 325B was mated with a number of black 99, including Black
Minorcas. Since these fowls have the zygotic constitution C2b2Ffi2,
compatible with the absence of barring, and of the inhibiting factor,
the cross should bring out a certain number of 99 manifesting
heterozygous barring. This has appeared to be the case. The
mating as made may be represented as follows :

The d^ 325B, [C2Bhf2i2] may be assumed to form gametes,

CBfi ' Cbfi
and the black 9 9 to form gametes,

ChFi • Chfi.

196 Bulletin No. 155.— 1913.

Since both d^ and 9 are now homozygous for C and ?', these symbols-
may be left out of the mating formulae:

& Bf ■ hi X
9 hF - hf =

9 fesFf— black
9 B6Ff — barred
cf 62/*2 — black
cf Bhfo — barred

In other words, provided cf 325B was actually heterozygous for
barring, this mating should give equal numbers of barred and black
birds, equally divided between the sexes. WTien we compare with
these theoretical deductions the experimental results presented in
Table 11, p. 175, it is apparent that there is close correspondence.
Similar results were obtained from mating of 6^ 325B with Black
Java 9 9 (Case 3f ) and Black Hamburg 9 9 . These matings served
to give a number of 99 heterozygous for the barred plumage-
pattern, and freed from the pigment -inhibiting factor; and these
fowls as described in Case 5 w^re mated in the season of 1913 \Nith
cf 477 V, a bird which show^ed better barring than325B. The data
on the results of these crosses are reported on p. 180.

( (White Leghorn d^ X Black Minorca 9 ) d^ )

Case 3d.— d^ ] ■ - X

( Black Minorca 9 )

(White Leghorn d" X Black Minorca 9) 9 .—(Table 12, p. 176).
Another method of testing the heterozygous nature of d^ 325B for
the barring factor was to mate this bird with (W. L. X B. M.)
Fi 99. These we assume are, themselves, heterozygous for the
barring factor and have the zygotic constitution C^BhFfli, a formula
compatible with barred plumage rendered obscure by the presence
of inhibiting factor /. These birds form gametes

ChFi ' CbFI ' CBfl ■ CBfi
In this case the presence of the inliibiting factor 7, in a heterozy-
gous condition, would interfere with the manifestation of the barred
color-pattern in one-half the progeny which would therefore be white.

Constitution of the White Leghorn Breed.

197

Among the other half, lacking the inhibiting factor, a part should be
barred and the remainder black.

If we assume that cf 325B, having the constitution C2B6/2I2, forms
gametes

CBfi ■ Chfi

and that the 9 9 [C^BhFJIi] form gametes

CBfi • CBfl ' ChFi ■ CbFI

the mating may be represented:

c^ CBfi ' Chfi X

9 CBfi ' CBfi • Chfi ' ChFI

^d"

99

^2^2/2/^, white
C.Bhf'di, white
C2B2f'dij barred
C2Bhf2i2, barred

' CiBhFjIi, white
C2h2FfIi, white
C2h2Ffi2, black
C2BhFfi2, barred

The data presented above may be summarized as follows :

Character.

a^

9

Total.

White

2
0

2

2

1
1

4

Black

1

Barred

3

Total

4

4

8

In other words, among every 8 birds resulting from this cross, we
should expect to find 4 whites, one black and 3 barred. Of the 4
white, one should be homozygous and 2 heterozygous for barring;

198

Bulletin No. 155.— 1913.

and of the barred birds one c/" should be homozygous, one hetero-
zygous, and one 9 heterozygous for this character.

The experimental data presented in Case 3c may now be compared
with these theoretical results. In Table 12, it was demonstrated
that of 34 birds raised 17 were white and 4 were black, while 13 were
barred as shown in the following diagram:

c^

9

?

Totals.

Character.

Actual.

Expected.

White

17
2

4

17

4

13

17

Black

Barred

1

7

1

2

414
12H

Totals

8

3

23

34

34

It will thus be seen that the correspondence between the actual
and the theoretical results is very close.

Case 3e. — d^

{ (White Leghorn cf X Black Minorca 9) d^

( Black Minorca 9

(White Leghorn cf X Black Minorca 9) d^ ]

1

X

, —(Table 13, p. 177).
Black Minorca 9

The experimental data presented under the head of Cases 3c and 3d
made it apparent that cf 325B was actually heterozygous for the
barring factor, and had the zygotic constitution, C2Bhf2i2- The next
step in the process of obtaining (from the 325 group) the barring
factor in a pure, homozygous condition was to obtain a 9 cross-
bred heterozygous for this character.

Under the heading of Case 3b it has been shown that from the
mating (White Leghorn X Black Minorca ) d X Black INIinorca 9
there were produced, along with the barred d 325B, black 99 and

Constitution of the White Leghorn Breed.

199

white 9 9 . From the mating in question one of each sort Uved to
maturity, black 9 325A and white 9 325E. A consideration of the
analysis presented on p. 177, made it seem probable that 325 A did
not possess the barring factor, its zygotic formula being 0262/^/^2.
The white 9 325E, however, might have had the zygotic constitu-
tion CiBhFfli (compatible with a barred plumage rendered obscure
by the presence of /) ; or the constitution C^^FfH (compatible with
the total absence of the barring factor). We may now consider the
details of these two matings, with the aim of demonstrating the actual
zygotic constitution of the black and the white female cross-breds
mentioned above, both being full sisters of cf 325B.

First Instance. — cf 325B (barred) X 9 325 A (black): As in-
dicated above, 6^ 325B [C2Bbf 012] may be considered to form gametes

CBfi • Cbfi
while the black 9 325 A (his sister) [0262^^2], forms gametes

CbFi ' Cbfi
The mating would then be represented :

9 CbFi • Cbfi X
cf CBfi • Cbfi =

9 C2b2Ffi2, black
9 C2BbFfi2, barred
cf 0262/2^2, black
d^ C2Bbf 212, barred

In other words, among every four birds two would be black and
two would be barred; and in each of these groups there would be one
cf and one 9 . Each of the barred birds would be heterozygous for
this character. The expectation m.ay be represented as follows:

Character.

cf

9

Total.

Black

1
1

1
1

2

Barred

2

Totals

2

2

4

200

Bulletin No. 155.— 1913.

When we compare these deductions with the results actually
obtained in experiments as presented on p. 177, it is apparent that
the experimental results come fairly close to the expected. Of 43
birds described when over 3 weeks old, 25 were barred and 18 were
black; and in each group the sex-ratios were approximately 1:1.

Second Instance. — cf 325 B (barred) X 9 32oE (white); first
possibility: We may consider first the case in which 9 32oE is
assumed to have the zygotic formula C2BbFfIi, compatible with
heterozygous barring rendered obscure by heterozygous /. As
before, cf 325B may be assumed to form gametes,

CBfi • Cbfi
while the 9 325E, forms gametes,

CbFI • CbFi ■ CBfl • CBfi
The mating would then be represented :

9 CbFI ■ CbFi • CBfl - CBfi X
d^ CBfi 'Cbfi =

d^d"

[C2i56/2/^ white
I CoBofJi, white
C 'iBbf 212, barred
^2^2/222, barred

99-;

[C262F///, white
C2BbFfIi, white
C2BbFfi2, barred

[C2b2Ffi2,h\a,ck

These data may be summarized as follows :

Character.

d^

9

Totals.

Black

0
2

2

1
2
1

1

White

4

Barred

3

Totals

4

4

8

Constitution of the White Leghorn Breed. 201

It is thus apparent that in the mating under consideration among
every 8 birds we may expect to have 4 white and 4 dark. Of the
whites, 2 will be d^ d^ and 2 99- Of the darks, one will be black
and 3 barred ; the black bird and one of the barred birds will be 9 9 .
It appears that the expectation of producing a c^ homozygous for
barring would here be attained. One out of every 8 birds (or one
among every 3 barred cf &) should be homozygous for B.

We may now compare with these theoretical data the results
obtained in the actual cross. As shown in Table 13 (p. 177), among
50 birds, 25 were white and 25 dark. Of the darks, 13 were black
and 12 were barred. According to expectation we should have among
48 progeny the same proportion of light and dark birds, but the barred
should stand in proportion to the blacks as 18 to 6; and all the blacks
should be 9 9 . It is at once apparent that these expectations are
b}^ no means fulfilled, and we may therefore turn to a consideration
of the second possible interpretation involving a different zygotic
constitution for 9 325E.

Second Instance. — (^ 32oB (barred) X 9 32oE {white); second
possibility: On p. 177 reference has been made to the fact that 9
325E, so far as appearance was concerned, might have been hetero-
zygous for the barring factor or might lack it. In the previous in-
stance the case has been considered in which the bird was assumed
to be heterozj^gous for B. In the present instance we may consider
the probable results of mating in case 325E lacked this factor but
was heterozygous for 7, — in other words, possessed the zygotic con-
stitution C'2!b2FfIi. The cT 325B would form gametes as previously
shown while the 9 might be assumed to form gametes

CbFI • CbFi • Cbfl : Cbfi

The mating would then be represented :

9 CbFI ' CbFi - Cbfl ■ Cbfi X
d^ CBfi 'Cbfi =

^d"

C2b2f2li, white
C2Bbf2li, white
I C2Bbf2i2, barred
I C2&2/2^2, black

202

Bulletin No. 155. — 1913.

99 \

C2h2FfIi, white
C2BhFfIi, white
CiBbFfio, barred
[ C262F/0, black

These data may be summarized as follows :

Character.

d^

9

Totals.

Black

1
2

1

1
2
1

2

White

4

Barred

2

Totals

4

4

8

From this it appears that among every 8 birds resulting from such a
cross as that being considered we should expect to have 4 whites and
4 darks. Of the white birds 2 would be d" d" and 2 99. Of the
dark birds 2 would be barred and 2 black, each group being equally
divided between the sexes.

We may now compare with these data the results obtained in the
cross 325B X 325E presented on p. 177, and attempt to decide
regarding the actual zygotic constitution of 325E. The actual and
expected results were as follows :

Character.

c^

9

Sex.

(?)

Totals.

Expected.

White ....

Black

Barred. . .

?
2
5

?

6
4

5
3

25
13
12

25

12^
123^

Totals. .

50

50

1

Constitution of the White Leghorn Breed. 203

It is at once apparent that there is close relation between the
actual and the expected results in these cases, thus verifying the
constitution of 325E as C2b2FfIi. It is therefore clear that neither
325A nor 325E could be used in further matings to produce a barred
strain. This purpose was served, however, by the barred 99,
daughters of 325B, secured in the 1912 matings from the black
mothers. These were mated in 1913, not with 325B, but with one of
his sons, 477V, a bird which possessed a somewhat clearer pattern,
and was chosen as one which might be homozygous for barring. The
details of these crosses are as follows :

I (White Leghorn X Black Minorca) d^

1 {

Case 5. — cf { [ Black Minorca 9

9 Black Java

bred 99, heterozygous for barring (Table 16, p. 177). Since the d^
477V and the barred 9 9 are homozygous for both C and i, these sym-
bols now may conveniently be left out of the mating formulae, which
may be given as follows:

The zygotic constitution of the cT" 477V is

Bbf2

forming gametes

The constitution of the 9 9 is
forming gametes

cf

X Cross-

Bf' bf
BbFf

bF ' Bf

The mating may therefore be represented:

9 Bf bF X ■
cf Bf bf =
d^ Bbf2, barred
cf -62/2, barred
9 b2Ff, black
9 BbFf, barred

204

Bulletin No. 155. — 1913.

These expected results may be summarized, and compared wdth
the actual results, as shown below:

Character.

Expected

Expected

99

Expected
totals.

Actual
totals.

Black

Barred

0
2

1
1

1

3

74

17.3

Totals

2

2

• 4

249

When the actual results (Table 17, p. 181) are compared with the
expected it is clear that there is a close agreement. At the time this
paper goes to press, it is impossible because of the immaturity of the
stock to ascertain the sex-ratios and their relation to barring. It
may be stated, however, that the 1913 progeny undoubtedly contains
the expected proportion of cf cf homozygous for barring. It already
appears possible to predict which these birds are by means of their
lighter color. In this young stock there have alread\' appeared birds
which possess a much better grade of barring than any observed in
the earlier stages of the investigation. To what extent selection for
two or three years may be effective in further improving the character
of the barred pattern remains of course to be ascertained. Suffice it
to say at present that the mating described in Case 5 has finally
yielded the expected c^ d^ homozygous, and 99 heteroz^-gous, for
the barring factor; and these birds will now be used as selection =
material for further improvement of the character under discussion.

B. Discussion of Additional Data not Included in the

Foregoing Cases.

During the course of these investigations a few other matings
bearing upon the constitution of the White Leghorn have been made.
These may be discussed briefly at this time, although the detailed
results must await further breeding. These data relate to (1) the

Constitution of the White Leghorn Breed. 205

-constitution of the W. L. 9 with reference to the factor I; (2) the
presence of factor C, or other factors for black pigmentation, in the
W. L. d^; (3) the possible identity between the factor I in the
W. L. and Bateson and Punnett's factor /, of the Brown Leghorn, — •
an inhibitor of the Silky tA'pe of mesodermal pigmentation in crosses
between the B. L. and W. S.; (4) the possible occurrence of barring
in other breeds of fowl possessing the "R-white." These points
may be taken up in the order of their presentation.

L — The constitution of the White Leghorn 99 with respect to factor
I. — In order to throw light on this point crosses were made during
the season of 19L3 between the B. H. d^ and W. L. 99, these being
the reciprocal of crosses mentioned earlier in this paper. Fi gave
only white birds, thus indicating the homozygous nature of the W. I;.
99 for the inhibiting factor. This result was naturally expected.

2. — The factor for black ^pigmentation in the W. L. cT. — It has been
assumed in this study that the W. L. d^ is essentially a black bird in
which the pigmentation is obscured b}^ the action of the inhibiting
factor I. It is now necessary to present the data upon which this
assumption is based. First it may be said that this assumption
regarding the zj^gotic constitution of the W. L. is in harmony with the
majority of the experimental results already presented. To assume
that the W. L. d^ lacks the factor for black pigmentation is not in
agreement with the results observed. But it has seemed possible to
throw light upon this matter by other means. If the W. L. d^ were
mated witn an R- white, such as the White Plymouth Rock, F2
should yield some pigmented birds in which the factors / and C had
become separated from each other. We may tentatively regard the
zygotic constitution of the W. P. R. 9 as C2B6F/12 forming gametes

cBJi ■ cbFi
"The mating would then be represented:

d^ CBU ' CBfl X

9 cBfl • cbFi =

9 C cBhFf I i — white

<d^ CcB2f2li — white

206

Bulletin No. 155. — 1913.

In an actual mating of this sort, of 63 Fi individuals all were white.
Of this number, however, 5 showed one or more barred feathers.
Except in the case of one 9 the sex of these birds was not ascertained.
Many of the Fi generation, as chicks, showed patches of black down
feathers, but when the birds had matured all barred feathers had
disappeared and both sexes were pure white except for occasional
black ticks. It is thus evident that, even in Fi, pigment appeared
from some source, although the parent breeds were in appearance pure
white. This result is explainable on the ground of the dilution of
the // of the W. L. to li in the cross-breds. Better evidence is
however, to be derived from observations on the Fo individuals.

In obtaining the F2, cross-bred cf 463A emploj-ed, was an almost
white bird, and may be assumed to form gametes of four sorts, as
follows:

CBfl • CBfi ' cBfl • cBfi
while the cross-bred 99 (463 E, F, J; 464 K, 1, X, Q) may be
assumed to form gametes of eight sorts:

CBfl • CBfi • cBfl ' cBfi
ChFI ■ CbFi • cbFI • chFi

The mating may l)e represented as follows:

9 CBfl ' CBfl ' cBfl ' cBfi • ChFI ■ CbFi • cbFI • cbFi X
d^ CBfl ' CBfi ' cBfl • cBfi —

C^BbFfl. (1), white
C2BbFfIi (2), white
CcBbFflo (2), white
CcBbFfli (4), white
99 i coBbFfh (1), white
ciBhFfli (2), white
C2BbFfi2 (1), white
C^BbFfi^ (1), barred
I CcBbFfi2 (2), barred

Constitution of the White Leghorn Breed.

207

r C2B2/2/2 (1), white

C^B^hli (2), white

CcB2f2l2 (2), white

CcB2f2li (4), white
99 \ C2B2/2/2 (1), white

C2B2f2li (2), white

C2B2f2i2 (1), white

C25 2/212 (1), barred
I CcB 2/212 (2), barred

The data given above may be summarized in the following table :

Character.

c^

9

Total.

White

13
3

13
3

26

Barred

6

Total

16

16

32

It is thus apparent that among every 32 F2 individuals, one would
expect to obtain 6 barred birds, equally divided between the sexes.
The results may now be compared with the expectations as follows:

Character.

Actual.

Expected.

Barred

11
50

llfk

White

49]%

Totals

61

61

These results appear to justify the view that either the W. L. d^
or the W. P. R. 99 must be homozygous for the factor for black
pigmentation. Since we know that whenever black pigmentation is

208 Bulletin No. 155. — 1913.

added to the barred pattern possessed as a eryptomere by the W. P. R.
breed, the barring appears, we are forced to the conclusion that this
breed does not normally carry this factor for black pigmentation but
that the character lies dormant in the W. L. stock reappearing when
it is freed from its inhibitor 7. The fact that no black individuals,
o^c^ or 99, but only barred (and white) birds arose fromi this
cross in F2 is additional proof of the homozygous condition of the
W. L. d^ with respect to the factor for barred plumage pattern.

There may be, however, one other possible explanation of the
appearance of black-pigmented feathers in Fi birds and a certain
proportion (6 in 32) of barred individuals in Fo. It is conceivable
that the W. L. d^ and the W. P. R. 9 each contain one of the factors
whose fusion is necessary for the full manifestation of black pig-
mentation. Bateson and Punnett {op. cit.) have described a case in
which the mating together of two R-whites produced progem- all of
which were dark colored. These factors may be designated .Y and Y
and it may be assumed that, while neither alone can determine black
pigmentation, X and Y working together {i. e., XY) are able to bring
it about. In case the W. L. cf was homozygous for the factor X,
and the W. P. R. 9 homozygous for the factor Y, all the offspring
would be AT, — compatible with black pigmentation. But upon the
assumption that the W. L. d^ is h, this pigment would not be mani-
fested in the Fi individuals. Making use of this hypothesis the
W. L. cf would be 82/212X21/2 forming gametes

BflXij • DflXij
while the W. P. R. 99, having the zygotic constitution BbFfu^XiY^j
would form gametes

BfixY ' hFixY
The mating would then be expressed:

d^ BfIXy • BilXy X
9 BfixY ' hFixY —

d^ & B2f2liXxYy, white
99 BhFfliXxYy, white
All of the Fi individuals are heterozygous for /, X and Y. The

Constitution of the White Leghorn Breed. 209

presence of X and Y together would determine pigmentation, but
this would be obscured by /, althougn in heterozygous condition. It
is conceivable, however, that li might permit a small amount of
black to appear in the early feathering of Fi; and this condition was
actually found to occur as also pointed out by Goodale (1910). In
this paper it has been shown to hold for Fi in nearly all of the White X
Black crosses.

In the production of F2 of the cross under discussion, a cf Fi white
cross-bred \E2f2liXxYy\ would form gametes of 8 sorts:

BJIXY • Bfixy • BfIXy • BfixY

Bfixy • BfiXY • BfIxY • BfiXy
w^hile Fi cross-bred 9 [BbFfliXxYy] would form 16 kinds of gametes:

BfIXY • Bfixy ' BFIXY ■ hFixy

BfIXy • BfixY ' hFIXy ' hFixY

BfIxY • BfiXY ' hFIxY • hFiXY

BfIxy • BfiXy • hFIxy • hFiXy
This mating would give 128 individuals possessing 27 different
zygotic constitutions as follows :

cf Combinations.

52/2/2X272 (1), white B2f2l2X2Yy (2), white

B2j2liXxYy (8), white 52/2/2X2F2 (1), white

^2/2/2X2 72/ (2), white B2f2lix2y2 (2), white

B2f2liXxY2 (4), white ^2/2/20:22/2 (1), white

52/2/2X^72/ (4), white -62/212^^22/2 (1), white

^2/2/1X272 (2), white B2f2i2X2Yy (2), white

52/2/2X0^72 (2), white 52/222X22/2 (1), white

B2f2liX2Yy (4), white 52/2/2X0:2/2 (2), white

52/2/2X0:2/2 (4), white B2f2i2X2Y2 (1), white

52/2/2X22/2 (1), white 52/222X0:72/ (4), barred

52/2/2X0:2/2 (2), white 52/222X0:72 (2), barred

52/2/2X22/2 (2), white 52/222X272 (1), barred

52/2/20:272/ (4), white 52/222X272/ (2), barred
52/2/20:272 (2), white

210

Bulletin No. 155. — 1913.

Females, heterozygous for B and F, would be formed in the exactly
same number and proportion as those indicated above for the cf cf" •

From this analysis it is apparent that among every 128 individuals
18 would be barred and 110 white, both the barred and the white birds
being equally divided between the sexes as follows :

Character.

d"

9

Total.

White

55
9

55
9

110

Barred

18

Total

64

64

128

In the following table, we may compare the actual with the ex-
pected results in F2 as formulated upon the present hypothesis:

Results.

White.

Barred.

Total.

Actual

50

49ft
52 it

11
lift

61

Fxpected*

61

Expectedf

61

♦Provided the W. L. (^ possesses the primary color factor, C. and the W. P. R. 9 9 possess no
contributing pigmentation factor whatever.

fProvided the W. L. (^ possesses the " X-factor" and the W. P. R. 9 9 the " Y-factor."

It is apparent from the summary presented above that on the basis
of the single-factor hypothesis we should obtain 12 barred individuals
in every 64, while on the double-factor hypothesis we should obtain
only 9 in 64. The experimental results, comprising observations on
61 F2 individuals, are slightly in favor of the former view. It must
be borne in mind, however, that the difference between the two groups
of expected results is slight, and final conclusions must be deferred

Constitution of the White Leghorn Breed. 211

until data are obtained on a larger number of F2 birds than form the
basis of present comparisons.

3. — On the nature of the factor I of the White Leghorn fowl. — Hereto-
fore in this series of experiments the inhibiting factor has been ob-
served only in its effect upon the factor (or factors) for black pigmen-
tation of the feathers, and (still unpublished) of the beaks and shanks
(epidermal pigmentation). Whether factor I has the power to
inhibit in all cases other colors, such as buff and red, cannot be stated
definitely at this time.* But one other point of interest has been
raised with reference to the factor / as a result of reciprocal matings
between the W. L. and W. S. breeds. The experimental data may be
presented as follows :

From the cross, W. L. cf X W. S. 9 all the progeny were white with
the exception of a few minute black flecks and an occasional suffusion
of buff on the breast or wing coverts. The d^ d^ and 9 9 were
exactly alike in appearance, not only with respect to the pigmentation
of the feathers, beaks and shanks (epidermal), but also with respect
to the typical mesodermal pigmentation of the W. S.

In the cross W. S. d^ X W. L. 9 the results were different:
With respect to plumage pigmentation, both cf cf and 9 9 were
heavily splashed with black. The pigmentation was perhaps more
apparent on the cf cf . With respect to the Silky type of pigmenta-
tion, the heavily pigmented birds (eyes, beak, shanks, wattles,
pleura, peritoneum, etc.), were invariably 99. It is apparent
that these results (so far as they relate to the inhibition of mesodermal
pigmentation in the c^ &), are in accord with the findings of Bateson
and Punnett (op. cit.) from observation of reciprocal crosses between
the Bro^vn Leghorn and W. S.

The results obtained by the present writer make it appear that the
W. L. 9 , as well as the B. L. 9 , possesses in heterozygous condition a
factor for the inhibition of the Silky pigmentation; and that the

*It can now be stated, as a result of later work, that the red of the Rhode Island Red breed, is
recessive to, and the buff of the Buff Leghorn and Buff Wyandotte dominant over, the white of the
White Leghorn.

212 Bulletin No. 155.— 1913.

inheritance of this inhibiting character is sex-hmited, being trans-
mitted from the 9 9 to the c^ c^ only.

The differences in plumage-color (i. e., heavily splashed Fi birds-
from the W. S. cf X W. L. 9 mating, etc.) are more difficult to
explain and no attempt will be made to do so at this time.

In conclusion it may be merely pointed out that the factor which
inhibits black pigmentation in the pluma^ge corresponds with Bate-
son's and Punnett's inhibitor of Silky pigmentation in so far as its-
effect is observed only in W. S. 6^ X W. L. 9 matings. But the
factors seem to be distinct in that, while the inhibitor of Silky pig-
mentation is strictly sex-limited (preventing deep pigmentation in
the Fi d' d' from W. S. d' X B. L. 9 ), the W. L. inhibitor of black
in plumage does not appear to be sex-limited, since the Fi from the
W. S. d^ X W. L. 9 cross are also deeply splashed with black. It
therefore appears that the White Leghorn breed of fowls possesses
at least two distinct color-inhibiting factors, — one for the Silky type
of pigmentation, the other for black pigmentation in the plumage.
These points require further study.

4. — The presence of the haired pattern in other breeds of fowl char-
acterized by the R-white. Outside of the White Plymouth Rocks,
which as is well known possess barring as a cryptomere, only two
other breeds characterized by the R-white have yet been tested for
their possession of the barring factor. These are (1) the White Silky,
(2) the White Minorca.

In the first of these crosses between the W. S. d^ and B. H. 9 , of
9 individuals all were black; these manifested also the dark shanks,
skin, and crest of the Silky. In F2 the results were:

Black, including 2 blue 33

White 10

Game pattern, variously modified 9

Thus the expected 3: 1 ratio appears among the black and the
white birds with no observed manifestation of the barred pattern.
No attempt will be made at this time to explain the appearance of

Constitution of the White Leghorn Breed. 213

the games.* It suffices the present purpose to state that the barred
pattern did not appear in either Fi or F2 of the White Silky X Black
Hamburg crosses.

In Fi of the matings between a White Minorca cf and Black
Hamburg 9 all the progeny were black, the d^ 6^ manifesting red
saddle feathers. In F2of this cross (1913) the results were: black
78, white 27, the expected being: black 78%, white 261^. No
barring appeared in either Fi or F2.

V. General Summary and Conclusions.

1. — In reviewing as a whole the results of the many crosses described
in the foregoing pages it becomes apparent that, as was stated at the
outset, the original aim of the investigation has not been realized.
The main purpose was (in 1909) to produce, and then to ''fix" the
barred plumage pattern by means of suitable matings of white with
dark birds, it being assumed tentatively that the barred plumage
pattern might represent, as many breeders have supposed, a hetero-
zygous condition of black and white, — a sort of a mosaic in the same
feather. It is true that a part of the aim has been attained, in so far
as a completely barred pattern was actually secured in F2 ; and a pure
strain of barred fowls has been built up from these barred F2 in-
dividuals. But a consideration of the nature of this barring, together
with a careful study of its manner of inheritance in the numerous
crosses mentioned above, leaves no doubt that it could not have been
produced de novo from the White X Black matings as first suspected,
but that it had its origin in a factor for barring present in the gametes
of the W. L. d^ . The evidence already presented indicates therefore
that the W. L. c?" is homozygous for this character B, while the 9 is
heterozygous. It also indicates that the W. L. cT" carries a factor, C,
or possibly other factors, for black pigmentation. This circumstance
would naturally bring out the barred pattern were it not for the
presence of an inhibiting fact, I, which represses the manifestation
of black, — a factor for which the W. L. cf is also homozygous.

*This point, together with others which have arisen in the course of the investigations, will be
considered in detail in a later publication.
5

214 Bulletin No. 155.— 1913.

2. — The zygotic constitution of the W. L. cf with respect to barring
and the other factors concerned has thus been given provisionally as
C2B?f2l2, and the 9 as C2-B62F//2. To what extent the W. L. stock
of this country and Europe possesses this formula cannot now be
definitely stated. All that may be said on this point at present is
that the data presented in this paper are based on experiments which
made use of som.e of the best W. L. stock obtainable.*

3. — The possible origin of the factor for barring in the W. L. has
not been considered in these pages and it is probably useless to
speculate on this point until we have more authoritative information
relating to the foundation of this breed and to the manner of pro-
duction of the various strains now scattered about the country.
Among them all there may exist several variations in zygotic constitu-
tion.

4. — The result of the reciprocal crosses between the W. L. and W. S.
indicates that cf cf of the former breed (as is also the case with the
Brown Leghorn c^) possess a factor which inhibits Silky pigmenta-
tion (mesodermal). The 99 are heterozygous for this character,
which is sex-limited in its inheritance. These '' inhibiting factors,"
apparently possessed by the Leghorn breed of fowls as a whole, are
of considerable interest and deserve further study. In the hands of
the intelligent breeder, they suggest an effective instrument for con-
trolling the manifestation of a variety of characters in poultry.

5. — Finally it may be said that the data reported in this paper
explain certain curious results obtained by both Davenport and
Hurst {op. cit.) with respect to barred progeny. They furthermore
give an explanation for the interesting phenomenon occasionally
observed by poultrymen, — the appearance of '' cuckoo" progeny in
Fi or F2 from supposedly non-barred parents; also for the otherwise
unexplainable circumstance that barred 99 have arisen from

♦Since the results presented in the body of this paper were secured, two other W. L. males have
been tested, one coming from Professor James E. Rice of the Cornell Agricultural College and
Experiment Station; the other from Professor Harry Lewis of the New Jersey Agricultural Experi-
ment Station. Both were found to possess the barring factor as indicated by the appearance of
barred feathers in the F^ individuals.

Constitution of the White Leghorn Breed. 215

barred mothers in the case of crosses with W. L. d^ c^, it being now
commonly assumed that the sex-limited character, barring, is in-
herited by -9 9 from the cf only.

As to the production of the barred pattern de novo, it has been in-
dicated that barring was not obtained from two cases of matings be-
tween Blacks (Hamburg) and recessive Whites (Silky and Minorca).
That the barred character can be produced, or "synthesized" from
breeds not possessing the factor for barring now seems improbable;
and we can agree vvith Correns (1905, p. 13) when he says: "Wo
Mosaikbildung als Regel bei einem Bastard auftritt, war sie schon in
einem der Eltern oder in beiden, aktiv oder latent, vorhanden."

VI. Literature Cited.

Bateson, W. and Punnett, R. C, 1908. Report to the Evolution
Committee of the Royal Society, IV, Publ. Harrison and Sons,
London.

., 1911. The inheritance of the pecuHar pigmentation of

the Silky fowl. Jour, of Genetics, I, (3), 185.

Cushman, Samuel, 1893. [On the production of market roasters].
Ohio Poultry Jour., 1893 II, 7, 185-191.

Davenport, C. B., 1906. Inheritance in poultry. Publ. 52 of the
Carnegie Institution of Washington, 17 pis., p. V-104.

,1909. Inheritance of characteristics in domestic fowl. Publ.

121 of the Carnegie Institution of Washington, 12 pis., pp. 1-100.

Good ALE, H. D., 1909. Sex and its relation to the barring factor in
poultry. Science, N. S., XXIX, (756), 1004-1005.

, 1910. Breeding experiments in poultry. Proc. Soc. Exper.

Biol, and Med., (7), p. 178-9.

Hurst, C. C, 1905. Experiments with poultry. Rpt. to the Evolu-
tion Committee of the Royal Society, II, Publ. Harrison and Sons,
London.

216 Bulletin No. 155.— 1913.

Spillman, W. J., 1908. Spurious allelomorphism [in poultry]. Am.
Naturalist, 42, (50).

Pearl, R., 1910. On the inheritance of the barred color pattern in
poultry. Arch. /. Entivicklungsmech., 30, p. 45-61.

, 1912. Notes on the history of barred breeds of poultry.

Biol Bill, 22, (5), 297-308.

Wright, L., 1905. The new book of poultry. London (Cassell).

VIL Description of Plates.

PLATE I.

Figure 1. White Leghorn cf", 193 A.
Figure 2. White Leghorn cf , 1 A.

PLATE II.

Figure 3. White Leghorn X Black Hamburg, Fi 9, 10 I.
Figure 4. AVhite Leghorn X Black Hamburg, Fi cT, 211 M2.

PLATE III.

Figure 5. White Leghorn X Black Hamburg, F2 9, 315 S.

Figure 6. Barred F3 d', 477 V. (See text, p. I8O).

Figure 7. Black Hamburg 9, 5 A.

Figure 8. Barred F2 d', 325 B. (See text, p. 175).

FIG. 1

FIG 3

\kk

CONTRIBUTIONS FROM THE DIVISION OF ANIMAL BREEDING AND PATHOLOGY.

SEniES Begih^sxsq 1909.

1. Com:, Leon J. — The orow a menace to poiiltry raising. R, I. Agr, Expi. Sla. Bpt.^ 1909,

pp. 312-316. Reprinted, 1909.

2. Miij:.er, Abthtjk C. — Mating experiments with beea. R. I. Apr. Ezpt. Sta. Rpt., 1909,

pp. 306-311. Reprinted, 1909.

3. Cole, Leon J. — Methods of keeping pedigree records in use at the R. I. Agricultural Experi-

ment Station. R. I. Agr. Expt. Sta. Rpt., 1909, pp. 317-324. Reprinted, 1909.

i. Hadlet, Phiup B. — Studies in avian coccidiosis: I. Wiiite diarrhea in chicks; II Roup in
fowls. Centbl. f. Bakt. [etc.], Abt. 1, Orig., 1909, 50 <3>, 348-353.

5. Hadlet, Philip B. — Note on the behavior of the domestic fowl, Amer. Nat., 1909, 43.

pp. 6G9-676.

6. Hadlet, Philip B. — Notes on the parasitism of Ct/iodiles nudu$ and Haemophysalu chordeilis.

Science, N. S., 1909, 30. p. 774.

7. Hadlet, Philip B. — Regarding the value of the van Gieson and the Romanowsky malarial

stains for the detection of coccidia. Centbl. /. Baki. [etc.], Abt. 1, Grig., 1909, 52 (1), pp.
147-150.

8. Cole, Leon J. and Hadlet, Philip B. — Ropy millr in Rhode Island. R. I. Agr. Expt. Sta.

Bui, 13G, pp. 129-152, June, 1909.

9. Cole, Leon J. and Hadlet, Philip B., with the assistance of Wm. F. Kirkpatrick. — Black-

head in turkeys. R. I. Agr. Expt. Sta. Bid. 141, pp. 137-271, June, 1910.

10. Hadlet, Philip B. — Studies in avian coccidiosis: III. Coccidiosis in the Engliiih sparrow and

other wild birds. Cenibl. f. Bakt. [etc.], Abt. 1, Grig., 1909, 56, 522-3.

11. Hadlet, Philip B., assisted by Amison, Elizabeth E. — Further studies on blackhead in

turkeys. Centbl. /. Bakt. [etc.], Abt. 1, Grig., 1910, 58, 33-41.

12. Hadlet, Philip B.— Fowl cholera and methods of combatting it. R, J. Agr. Expt. Sta. Bui.

144, pp. 309-337, November, 1910.

13. H.\DLBT, Philip B. — Eimeria avium: A morphological study. Archiv. /. Prolistenk, 1911,

22, 7-50.

14. Hadlet, Philip B., and Amison, Elizabeth E. — A biological study of eleven pathogenic

organisms from cholera-like diseases in poultry. R. I. Agr. Expt. Sta. Bui. 146, pp. 43-102.
June, 1911.

15. Hadlby, Philip B.— Studies on fowl cholera: I. A biological study of ten strains of the fowl

cholera organism. Centbl. f. Bakt. [etc.], Abt. 1, Grig., 1911, 61, 323-335.

16. Hadlet, Philip B. — Studies on fowl cholera-. II. The r61e of an homologous culture of slight

virulence in the production of active immunity in rabbits. R. I. Agr. Expt. Sla. Bui.
160, pp. 81-171, March. 1912.

17. Hadlet, Philip B. — Studies on fowl cholera: II. Active immunity in rabbits. Cenibl. f.

Bakt. [etc.], Abt. 1, Grig., 1913, 69, (4), 271-311.

18. Hadlet Philip B. — ^The presence of the barred plumage-pattern in the White Leghorn

breed cf fowls. American Naturalist, 1913, 47, pp. 418-428; with 6 figures in text.

19. Hadlet, Philip B., with the assistance of Dobotht W. Caldwell and C. H. MAaooN

— Studies on inheritance in poultry: I. The constitution of tiie White Leghorn breed
R. I. Agr. Expt. Sta. Bui., 155, pp. 151-216, Pis. I-III, June, 1913.