attacks of the Russians the previous autumn, was compelled to surrender.

Meanwhile, in January, Russia once more attempted to carry out the other
part of her general plan, the invasion of East Prussia. The Russian
troops succeeded as before in entering the coveted territory, this time
crossing the troublesome lake region while the waters were frozen. Soon,
however, the invaders met with a decisive defeat. In the Battle of the
Mazurian Lakes, General Von Hindenburg took 100,000 Russian prisoners;
the number of killed and wounded Russian soldiers is said to have been
150,000. The Russians hurriedly retreated from German soil.

The time had now come for the Germans and Austrians definitely to assume
the offensive. A strategic blow in Galicia imperiled the whole Russian
front and compelled a general retreat of the Russian armies in Galicia
and Poland. In June both Przemysl and Lemberg were recaptured by the
Central Powers. By September all of Russian Poland had been conquered.
Russia had lost 65,000 square miles of thickly populated territory. But
the land was so thoroughly plundered by the German conquerors that many
of the people died of starvation.

BULGARIA ENTERS THE WAR.--The sympathies of the Bulgarian government
had been with the Central Powers from the beginning of the war. Bulgaria
had not forgiven the neighboring Balkan states for their treatment of
her in the second Balkan war (1913). Against Serbia her feeling was
particularly bitter. The Allied disaster at Gallipoli and the military
successes of Germany and Austria in Poland and Galicia in the spring and
summer of 1915 led the Bulgarians to believe that now was the time for
them to strike. In October Bulgaria declared war upon Serbia, thus
definitely taking her stand as an ally of the Central Powers.