the nth for the Bulgarians.

The bombardment opened on the 5th, laying towns and vil-
lages in ruin all along the line; but on the Serbian side only out-
posts held the river lines, local reserves being kept under cover.

Kovess's main crossing place was to be Belgrade, opposite
which place technical preparations had been multiplied and two
corps out of three assembled. The third (XIX. Austro-Hunga-
rian) was to pass the Drina at Byelyina, and the Sava at Shabats,
Kupinovo, Progar and Zabrezh, in order to create bridgeheads
and to prevent the defenders from concentrating to the eastward

Gallwitz's crossings were to take place at Ram and at Semen-
dria, on each side of the Morava mouth, opposite which points lay
the railheads, and at the island of Temes Sziget between them;
the attack was to be accompanied by a demonstration from
Orsova and a Bulgarian threat towards Negotin.

On Kovess's front the secondary crossings, especially in the
Machva, secured footholds on the S. side of the water, but all
attempts to advance out of the waterlogged river valleys them-
selves were checked (Oct. 7). Opposite Belgrade, in the early
morning hours of the 7th, the first boatloads of troops of the VIII.
Corps pushed off into the stream under cover of innumerable
searchlights, heavy artillery fire, and monitor activity, while a
little way up the Sava the XXII. Res. Corps put over its advanced
troops into Ostrovo Tsiganliya (Gipsy Island). Zhivkovich had
16 battalions and nearly all the Serbian heavy artillery, including
French and British 6-in. guns, to oppose to them. The landing
the only operation in the World War analogous in form and spirit
to that of the Gallipoli Peninsula succeeded, but only after the
fiercest fighting was the foothold really made good and room
secured on the front of both attacking corps for the passage and
deployment of large forces. On the night of g-ioth, Zhivkovich
abandoned the attempt to hold the town, and fell back a little
way S., on the line Zarkovo-(249)-Visznitsa.

Simultaneously, Gallwitz's 3 corps had been launched, on both
sides of the Morava. Preceded by a demonstration at Orsova on
the 6th, the left corps (X. Res.) forced the passage at Ram on the
night of 6~7th, and drove inland, over the Anatema heights to
Kuryatse, threatening Pozharevats from the north-east. The IV.
Res. Corps (3 divisions) seized Temes Sziget Island with little
difficulty and reached Brezhani (Brezani). But the front from
Semendria to Gatsko defied the III. Corps, and not only pro-
tected the right rear of Zhivkovich, but gave time to Putnik to
bring troops from the Machva. 4

Nevertheless, it was clear by the nth that the nver barrier was
lost and Putnik began a steady policy of fighting successive de-
laying actions on the N. front, while at all costs keeping back the
Bulgarians on the right and rear, in order to gain time for the
arrival of French and British aid, the first elements of which had
already reached Salonika.

On the 1 2th Mackensen opened the general advance, in the
midst of a gale which, known as the Kossova, descends season-
ally upon the country from the south-east. Kovess made slow
progress till the i6th, when the Serbians evacuated under pres-
sure the Petrov Grob-Avala-Velika Kamen line, and fell back to
Melyak-Ripany-line of R. Ralya.

Gallwitz by that date had enforced the evacuation of Pozhare-
vats, cleared the way for his III. Corps to advance on the Semen-
dria front, and brought his left flank to Bozevats. To the E. of
Kovess, the Austrian offensive was a simple follow-up of the
retiring Serbs, who now attempted no real defence W. of the
Kolubara, though small forces with local riflemen delayed the
Austrians long enough for the families and the live stock to be
evacuated on Valyevo. The Montenegrins, and with them some
Serbs, were maintaining a particularly independent struggle
between the Yadar and the Lim.

By this time the Bulgarian advance on the right flank had
begun, though some days later than had been intended. In the
south, Todorov's II. Army (7th Div. with improvised formations)

3 The Drina portion of Kovess's army was, however, behind time.

4 AH Austrian forces in Bosnia were late in their preparations
and took no effective part in the offensive.



418



SERBIAN CAMPAIGNS



prepared to threaten the flank of the Salonika railway from Stru-
mitsa, the Ovchepolye from Kyustendil, and Vranya from Trn.
The I. Army advanced on the various routes to attack Zayechar,
Knyazhevats and Pirot; on these the Serbs had advanced to meet
them, always with the idea of gaining time, and by the i6th very
little progress had been made by the invaders, except by one
regiment which by a daring mountain march seized Vranya and
cut the railway there. This success weakened the position of the,
Serbian forces on the Egri Palanka road at Stratsin, and when,
farther S., Todorov turned their right by Kochana and pushed
cavalry to Veles, they evacuated the Ovchepolye (Oct. 18-19).
On the zist Uskub itself fell into the hands of the Bulgarians and
the Salonika line was lost, though a counter-attack recovered
Veles from the Bulgarian cavalry two days later.

At that moment for the first time, the French from Salonika
came into action, threatening Strumitsa and Todorov's left.
It was too late.

On the northern wing of the Bulgarian army, Boyadiev's cen-
tral columns cut the road between Zayechar and Knyazhevats
on the 2ist, and farther to the Bulgarian right, Negotin was
occupied by the invaders, who there made contact with the
Orsova detachment of the XI. Army. The Serbs in this quarter
offered little resistance, their rear being already threatened by
Gallwitz's progress in the Morava valley.

In that region the fighting had been heavy, the weather severe,
and it was not till the igth that Mackensen's two armies mastered
the Ralya line. On the 2ist, the date on which the Bulgarians
seized Uskub and the French came on the scene at Strumitsa
station, Mackensen's N. front was marked by the line Shapina-
Selevats-S. of Kosmay. On the 23rd it lay on the line Lazare-
vats-N.of Arangyelovats-N.of Palanka-Petrovats, and the Ser-
bian eastern fronts began to be in difficulties, though some days
were still to elapse before Goykovich's force finally disappeared
and junction was effected between Boyadiev's right and Gall-
witz's left. In W. Serbia the Austrians from Bosnia were begin-
ning to be active, and the country-side was being evacuated by
men, women and children, with their animals and belongings.
From Uzhitse as well as from Valyevo, the emigration had set in
towards Novipazar.

Putnik's left armies were now falling back concentrically
towards Kralyevo-Krushevats, in proportion as his E. front
caved in. On Oct. 30, after no light efforts, the XIX. Austro-
Hungarian and XXII. Res. Corps of Kovess's army were S. of
Gorni Milanovats, the VIII. Austro-Hungarian Corps S. of
Raibrovats, Gallwitz's army to the S. of Lapovo-Petrovats. The
Serbs had evacuated Zayechar on the 25th, Knyazhevats on the
2yth, and after a fierce resistance and repeated counter-strokes
from Pirot, Stepanovich had retired on Bela Palanka on the 29th.
Farther to the S., Todorov's attention had been thoroughly
attracted to the Strumitsa side, and the position at Uskub and
on the Upper Vardar had scarcely changed.

From Nov. i onwards, the final desperate effort was made by
the Serbians to gain time for the arrival of the French and British
by holding the arc Chachak-Kraguyevats-Yagodnya-Nish-Les-
koyats. Still the Bulgarians were held back in this phase, but
the Germans and Austrians steadily advanced. Kraguyevats
fell, with its arsenal, on Nov. i ; Yagodnya on the 3rd, Kralyevo
on the same day, Paratyin on the sth. For some days longer the
defence continued stubborn on the S. side of the W. Morava and
about Varvarin in the Morava valley, where a salient was held
to enable the last elements of the Serbian IV. Army (Goykovich)
to extricate itself from the closing vice. But by the gth the
defence on this line was at an end, and Mackensen was preparing
the dispatch of the XXII. Res. Corps to another theatre, having
received the Alpine Corps (division) in lieu.

On the E. front meantime, Stepanovich's counter-attacks had
completely held up the Bulgarians at Bela Palanka, while a great
part of the population flowed away through Nish into Kossovo.
It was not until Nov. 4, when Boyadiev had received a fresh
division (the 9th) and Paratyin had fallen, that orders were given
to evacuate Nish, and that centre was held by rear-guards till the
Sth. Leskovats resisted till the 7th.



The Orient railway, the objective for which Falkenhayn had
planned the campaign, was now clear from Germany to Con-
stantinople, and with his usual economy he was already think-
ing of withdrawing the German forces to other theatres. 1 The
Serbian army, plainly in dissolution, had ceased to be a menace
to the Danube monarchy. But new problems were arising the
Albanian question, the problem of Greece and the Allied Salo-
nika army, the question of a submarine base on the Aegean. In all
these, each of the three victors had a different standpoint, and
fresh difficulties set in between the three Governments. Belong-
ing as they do to the Salonika phase of the Balkan campaigns,
these problems will not be dealt with here, and it only remains to
describe, briefly, the last stages of the Serbian tragedy.

Substantially, the results of the Bulgarian cooperation had
fallen considerably short of what was expected. The tough
resistance of Stepanovich, and even of the small IV. Army in
the N.E. corner, had kept back the eastern danger until it was
too late for an envelopment. Indeed, considerable portions of
Boyadiev's army those oriented on Negotin and Zayechar, if
not also that on the Knyazhevats route were already crowded
out of the closing front. For effective envelopment of the
Serbian right, there only remained the N. portion of Todorov's
II. Army, and, with the increasing arrival of French and
British in the region of Rahovo and Doiran, this Bulgarian
general was obliged to be cautious, while encircling attack upon
the Serbian left was practically excluded by the fact that the
Bosnian forces had made a late start and were traversing very
difficult country. Supply and weather conditions, moreover,
were becoming serious for the invaders. Practically, nothing
could now prevent the remnant of the Serbian army from escap-
ing into Albania, should it choose to do so.

But for this desperate measure, which would involve the loss
of all war material and of many thousands of lives in the road-
less, snow-bound interior of Albania, the Serbian command was
not yet prepared. It seemed preferable to attempt to break
through towards the S., where the long-expected Allied army
was now advancing and Todorov was in difficulties.

The II. Bulgarian Army had, after seizing Uskub and taking,
losing and retaking Veles, moved out fan-wise against the
mountains N.W. and W. of Vranya, Kachanik, Kalkandclen,
and the Babuna pass, while its extreme left was on the defensive
against Sarrail's Rahovo group, and its left centre column was
moving down from Shtip on Krivolak and Kavadar, where also
Sarrail was collecting a considerable force. In the existing con-
ditions it was evidently more important, from Todorov's point
of view, to bar the Vardar valley against Sarrail than to attempt
to force the mountain barrier of the Kara Dagh and the Shar
Dagh. He therefore placed his centre of gravity well to the S.,
leaving his N. flank covered by a mixed force drawn partly from
the I., partly from the II. Army.

Against this force, Putnik assembled the remnants of 5 divi-
sions E. of Prishtina, and with them assumed the offensive with
all the violence of which his troops were still capable, on Nov. 9.

This began on the gth, driving the Bulgarian group of General
Ribarov back to Vranya in the one direction and towards Kuma-
novo in the other. By the isth Ribarov's right was in extreme
difficulties. But the arrival of part of the I. Bulgarian Army
from Leskovats on the left rear of the attacking wedge rescued
it. By now the general front of the Austrian and German pur-
suit had reached Uvats, the line of the Ibar, Yaver (Javor),
Kurshumlye. Pressure on the rear was too close to allow of
persistence in the southward break-through. The moral rally
which had permitted that attempt was dying away on all the
defended avenues, and Putnik made up his mind to escape
through Albania with what could be saved of the army and the
people. Between Nov. 20-25, the historic Kossovopolye witnessed
another last effort of the Serbian people, then everything flowed
away towards Ipek (Pech), Dyakovo and Prizren.

At these points the pursuit ceased in the first week of Decem-
ber. It had practically become Bulgarian alone. Such German

1 As above mentioned, Mackensen was given orders almost on
the battlefield to send away the XXII. Res. Corps.



SERVIA SEX



419



troops as remained in the theatre when Falkenhayn's orders had
been carried out were sent down the Vardar, into the midst of
the Bulgarian II. Army. The Austrians diverged into Monte-
negro, which was completely occupied, with some severe local
fighting and much secret negotiation, by the third week in Jan.
1916. But the end of pursuit did not mean rest and reorgani-
zation for the poor remnant of the Serbian army. It was impos-
sible to live at the halt; and a midwinter march through the
Albanian mountains, brought those whom its rigours left alive
to the coast of the Adriatic. Thence, after some delay, they were
transferred to Corfu, where the Western Powers provided food,
equipment, clothing and stores, so mitigating a disaster that
they might have prevented. (C. F. A.)

SERVIA: see SERBIA.

SETON-KARR, SIR HENRY (1853-1914), British big-game
hunter, was born in India Feb. 5 1853. Educated at Harrow and
Corpus Christi College, Oxford, he was called to the bar in 1879,
but developed a taste for travel and big-game hunting which
carried him all over the world. He also interested himself
in state colonization and was a member of the Royal Commission
on Food Supplies in Time of War. He published The Call to Arms
(1900-1) and My Sporting Holidays (1904). He represented
S.W. Lanes. (St. Helens) in the House of Commons from 1885 to
1906 and was knighted in 1902. He lost his life when the " Em-
press of Ireland " sank in the river St. Lawrence May 29 1914.

SEX (see 24.745*). The problem of the determination of sex
has in recent years been greatly elucidated. Knowledge has come
from several sources. Both breeding experiments and cytological
observation have severally led, as will be seen, to concordant con-
clusions, proving that the sex of the offspring is generally decided
by one or other of the germ-cells which unite in fertilization. But
though in ordinary circumstances the mode of determination is
now known, there are nevertheless indications that in special
cases the normal course may be altered or at least disturbed by
various influences, the operation of which is not understood. The
reconciliation of this latter class of evidence with the former has
not yet been satisfactorily effected.

Sex Determined by Spermatozoa. Knowledge of sex-determi-
nation began with the observation of Henking (1891) that in cer-
tain insects the spermatozoa were of two kinds, (i) those which
contained a supernumerary, unpaired, or accessory chromosome
(see CYTOLOGY), now generally called the X-chromosome, and
(2) those without this body. McClung (1902) first suggested
that this chromosome might be a determiner of sex, and took it
to be the peculiarity of the male, but Miss Stevens (1905) and
E. B. Wilson (1905), to whom the development of this part of
the subject is chiefly due, proved that the spermatozoa bearing
the X-chromosome are in these animals destined to form females.
The eggs are alike in each possessing an X, and thus the somatic
or diploid cells of the daughters come to have 2 X, one received
from their mother and one from their father, whereas the diploid
cells of the sons have one only, received from their mother.
Since the gametes of the male are of two kinds, that sex is said to
be hetero-gametic, the female being homo-gamelic. Further obser-
vation, however, showed that the organization of even nearly
allied genera of insects is by no means uniform in respect of the
sex-chromosomes. Though unpaired in the males of some
genera, the X may in others have a pair or " mate" of smaller
size, known as the Y-chromosome. Between these and other
genera in which the male has a pair of sex-chromosomes not visibly
different from each other there are several transitional conditions.
In a considerable number of forms also, the X is represented by a
group of separate chromosomes, regarded as collectively the
mates of the Y.

The X-chromosome has been seen in several orders of insects,
especially Hemiptera, Orthoptera and Coleoptera, in spiders,
myriapods and some nematodes. In man it is said (Guyer) to
be represented by a pair corresponding to a single Y-chromosome.

Sex Determined by Ova. Naturally this discovery that the
male is hetero-gametic was at first supposed to be of universal
application, but the next advance, which resulted from experi-
mental breeding, showed that this simple view could not be enter-



tained. The Currant Moth (Abraxas grossulariata) has a variety
lacticolor, characterized by a deficiency of black pigment, till then
known only in the female. Doncaster, instituting experiments
with this variety, found that by breeding such females with nor-
mal males the Fi family consisted of males and females, all
normal. 1 Interbred, these gave Ft composed of two normal
males: one normal female: one lacticolor female. But lacticolor
9 XFicf produced families containing normal o", normal 9 , lacti-
color cf and lacticolor 9 , all in equal numbers. On breeding any
normal grossulariata 9 with the lacticolor & now produced, the
sons were all grossulariata and the daughters all lacticolor.

Other interpretations have been proposed, but it is evident
that the eggs of the grossulariata 9 are of two kinds, (i) those
which are destined to be females, and do not carry the grossu-
lariata factor, (2) those which do carry this factor, and are des-
tined to be males (Bateson and Punnett). Taking the factors
G, grossulariata: g, its absence; F, femaleness: /, its absence, the
results may be represented symbolically thus:
I. Lact. 9 XGrosscf

F/:gg I ff.Gg



r

F Gross 9

F/:Gg

gametes Fg ; /G



X



Gross cf
Jf-Gg
/G;/g



I

I Gross 9
F/;Gg



i Lact. 9
F/:gg



2 Grossed



I I

Lact. 9 Gross 9
F/.gg Ff.Gg
Gross 9



Lact. 9 X transmitting Gross o*
F/.gg I ff.Gg



X



I I

Lact. c? Gross c
Jf.gg ff.Gg
Lact.c?



gametes Fg;/G



Lact. 9s Gross cTs

F/:gg /.Gg

Sex- Limitation and Sex-Linkage. Such a system of heredity
is sometimes called " sex-limited," and the descent of the charac-
ter so limited serves as an indication of the mode by which the
factor determining sex is transmitted from parent to offspring.
The proof that in these moths sex is determined by the eggs, or
in other words that the female is the hetero-gametic sex, is thus
complete. The same has been shown to be true of birds. In
fowls, several conditions have been shown to be sex-limited to
females; e.g. black as against the cuckoo-markings of the Plymouth
Rock; golden (as in Sebrights or Hamburgs) as against silver;
the black pigment of Silky fowls is suppressed by a sex-limited
factor -which inhibits this development, etc. In canaries the
peculiar form of albinism known as Cinnamon, and in doves
the pale albinotic variety shows a similar behaviour. We have
thus to recognize that, paradoxical as it may appear, sex is in
some animals determined by the sperm, and in others by the
eggs. Man belongs to the former class. Apart from the cyto-
logical evidence, as yet unconfirmed, the descent of sex-limited
conditions, notably colour-blindness, demonstrates this. Substi-
tuting male for female, colour-blindness, is transmitted in man
exactly as the lacticolor character is in the moths. A colour-blind
man mated with a normal woman has sons and daughters with
normal colour-vision. The sons cannot transmit the colour-
blindness, but the daughters transmit it to half their sons who
are therefore colour-blind. Moreover, when the transmitting
female is mated with the colour-blind man, the colour-blind fe-
male is produced, just as in the corresponding mating (3) in the
grossulariata experiment, the lacticolor male was formed. Finally
when the colour-blind woman mates with a normal man the sons
are all colour-blind and the daughters are all transmitters.
Following Doncaster's notation in the grossulariata scheme, if M,
maleness, be substituted for F, and N, normal colour-vision, for
G, the same analysis represents the observed facts: the transmit-

1 In genetics the following symbols are frequently used :9 = female;
cf =male; X = mated with; FI, F 2 , etc. = the first filial family, the
second, etc.



" These figures indicate the volume and page number of the previous article.



420



SEX



ting female (Nnmm) in man, for example, corresponds with the
male Ggff, etc. in grossulariata.

There is thus no doubt that just as in the bird and the moth
the female produces two kinds of eggs destined respectively to
form females and males, so in man the male produces two kinds
of sperms destined to form respectively males and females.

Cytological Interpretation. The notation given above provides
the simplest representation of the empirically observed facts
without any attempt to refer them to cytological phenomena.
This attractive branch of Genetics has been actively developed
by T. H. Morgan and his colleagues with remarkable success;
and though serious difficulties remain, the incidence of the sex-
limited characteristics can so readily be interpreted as depending
on the distribution of sex-chromosomes, observed or hypotheti-
cal, that a causative influence has with great plausibility been
attributed to them. Starting from the now familiar fact that in
certain animals the XY male has visibly one X-chromosome and
the XX female two, it is argued that the " double dose " of X is
the cause of the female characteristics and that one dose of the
same element produces the male attributes. If, then, in such
animals the dominant factors, which show linkage, be supposed
to be also carried in the X-chromosome, the sex-limited distribu-
tion of the negative characteristics to males will result. At first
sight the fact that in other animals the female is hetero-gametic
seems irreconcilable with this scheme, but, by making the assump-
tion that in these females a similar cytological apparatus exists,
the genetic observations may be represented on the same plan as
that adopted for the hetero-gametic males. For the hetero-
gametic female may be represented as XY and the male as XX,
and here again if the X carries the positive element, say the G of
grossulariata, then the gamete of the composition XG is always
destined to the sons, and Yg to the daughters, as the facts re-
quire. Perhaps the strongest evidence in favour of the chromo-
some hypothesis has been found in the phenomenon of "non-
disjunction " in Drosophila, the fruit-fly, whose genetical composi-
tion has been studied more fully than that of any other organism
(see GENETICS). In this creature sex-limitation is to males, and
the male is hetero-gametic; but, exceptionally, unexpected forms
appear, as, for instance, red-eyed males in the mating where
white-eyed alone should normally be produced. Bridges found
that in such individuals and among the families containing these
abnormal members, irregularities in the occurrence of the
chromosomes could be demonstrated. Apparently in some
maturation division two X-chromosomes had passed to the same
egg, others receiving none. From this a series of exceptionally
constituted gametes are derived which could have brought about
the observed exceptions. Another line of argument pointing to
the same conclusion has been derived by Morgan and his asso-
ciates from a study of gynandromorphs the curious individuals
composed of more or less irregular patchwork of male and female
tissues, which are formed with some frequency especially among
the various orders of insects. A number of these have occurred
in the pedigreed families of Drosophila, and on analysis it was
found possible in almost every case to refer the characters shown
in the several parts to their parental origin.