las.]

The northern wall of the Apennines and the outpost barrier of the Alps
have combined to protect peninsular Italy from extensive ethnic
infusions from the direction of the continent. This portion of the
country shows therefore, as the anthropological maps attest, a striking
uniformity of race. It has been a melting-pot in which foreign elements,
filtering through the breaches of the Apennines or along the southern
coast, have been fused into the general population under the isolating
and cohesive influences of a peninsular environment.[796] The population
of the Iberian Peninsula is even more unified, probably the most
homogeneous in Europe. Here the long-headed Mediterranean race is found
in the same purity as in island Corsica and Sardinia.[797] Spain's short
line of contact with France and its sharp separation by the unbroken
wall of the Pyrenees robs the peninsula of any distinctly continental
section, and consequently of any transitional area of race and culture;
hence the unity of Spain as opposed to that twofold balanced diversity
which we find in Italy and India. The Balkan Peninsula, on the other
hand, owing to the great predominance of its continental section and the
confused relief of the country, has not protected its distinctively
peninsular or Greek section from the southward migrations of Slavs,
Albanians, Wallachians, and other continental peoples.[798] It has been
like a big funnel with a small mouth; the pressure from above has been
very great. Hellas and even the Peloponnesus have had their
peninsularity impaired and their race mixed, owing to the predominant
continental section to the north.

[Sidenote: Peninsulas as intermediaries.]

Peninsulas, so far as they project from their continents, are areas of
isolation; but so far as they extend also toward some land beyond, they
become intermediaries. The isolating and intermediary aspects can be
traced in the anthropo-geographical effects of every peninsula, even
those which, like Brittany and Cornwall, project into the long uncharted
waste of the Atlantic. In the order of historical development, a
peninsula first isolates, until in its secluded environment it has
molded a mature, independent people; then, as that people outgrows its
narrow territory, the peninsula becomes a favorable base for maritime
expansion to distant lands, or becomes a natural avenue for numerous
reciprocal relations with neighboring lands beyond. Korea was the bridge
fo