rule would obtain south of the Alps. If this relation does not hold, there must obviously be something environmentally the matter. Let us examine the facts.
The Black Forest in southwestern Germany affords us a good opportunity for the comparison of relatively pure and mixed
Pure Blond Teutonic Type. Cephalic Index, 75.
populations. This mountainous, heavily wooded district, shown in our map, lies close by the upper courses of the two principal rivers of Europe, which have both formed great channels of racial migration. The Rhine encircles it on the west and south, and an important affluent of the same river bounds it on the east; for the Neckar drains the fertile plains of Würtemberg, or Swabia, which lie about Stuttgart. This capital city, it should be observed, lies not far from the point of that blond Teutonic wedge which, we have already shown, penetrates central Europe from the north. Finally, the Danube, not shown upon the map, takes its source in the southeastern part of the Forest, and has therefore opened up still another route of racial immigration from this quarter.
There is every evidence that here in the Black Forest is a mountainous area of isolation containing a people which is distinctly Alpine in type of head form as compared with the mixed populations of the fertile plains and valleys round about it. For example, the cephalic index in Wolfach in its center is above 86, three units and more above the average for the Rhine Val-
