present
Americans with their ancestors, because measurements of the latter are
lacking. But to assume that the early colonists did not differ greatly
from the modern English is probably justifiable. A comparison of modern
Americans (of the old white stock) with modern English should give basis
for an opinion as to whether the English stock underwent any marked
modifications, on coming to a new environment.

It has already been noted that the average cephalic index is practically
the same; the only possibility of a change then lies in the amount of
variability. Is the American stock more or less variable? Can a
"melting pot" influence be seen, tending to produce homogeneity, or has
change of environment rather produced greater variability, as is
sometimes said to be the case?

The amount of variability is most conveniently measured by a coefficient
known as the standard deviation ([Greek: s]), which is small when the
range of variation is small, but large when diversity of material is
great. The following comparisons of the point at issue may be made.[202]

Avg. [Greek: s]

100 American men 78.3 3.1
1011 Cambridge graduates (English males) 79.85 2.95

For the men, little difference is discernible. The Old Americans are
slightly more long-headed than the English, but the amount of variation
in this trait is nearly the same on the two sides of the ocean.

The average of the American women is 79.5 with [Greek: s] = 2.6. No
suitable series of English women has been found for comparison.(203) It
will be noted that the American women are slightly more round-headed
than the men; this is found regularly to be the case, when comparisons
of the head form of the two sexes are made in any race.

In addition to establishing norms or standards for anthropological
comparison, the main object of Dr. Hrdlicka's study was to determine
whether the descendants of the early American settlers, living in a new
environment and more or less constantly intermarrying, were being
amalgamated into a distinct sub-type of the white race. It has been
found that such amalgamation has not taken place to any important
degree. The persistence in heredity of certain features, which run down
even through six or eight generations, is one of the remarkable results
brought out by the study.

If the process could continue for a few hundred years