ense that the people of one community are unable to
understand the people of another. But such a development of languages is
not differentiation in the sense in which this term is here used, and
often used in biology, but is analogous to multiplication as understood
in biology. The differentiation of an organ is its development for a
special purpose, _i. e._, the organic, specialization is concomitant
with functional specialization. When paws are differentiated into hands
and feet, with the differentiation of the organs, there is a concomitant
differentiation in the functions.

When one language becomes two, the same function is performed by each,
and is marked by the fundamental characteristic of multiplication,
_i. e._, degradation; for the people originally able to communicate with
each other can no longer thus communicate; so that two languages do not
serve as valuable a purpose as one. And, further, neither of the two
languages has made the progress one would have made, for one would have
been developed sufficiently to serve all the purposes of the united
peoples in the larger area inhabited by them, and, _coeteris paribus_,
the language spoken by many people scattered over a large area must be
superior to one spoken by a few people inhabiting a small area.

It would have been strange, indeed, had the primitive assumption in
philology been true, and the history of language exhibited universal
degradation.

In the remarks on the "Origin of Man," the statement was made that
mankind was distributed throughout the habitable earth, in some
geological period anterior to the present and anterior to the
development of other than the rudest arts. Here, again, we reach the
conclusion that man was distributed throughout the earth anterior to the
development of organized speech.

In the presence of these two great facts, the difficulty of tracing
genetic relationship among human races through arts, customs,
institutions, and traditions will appear, for all of these must have
been developed after the dispersion of mankind. Analogies and homologies
in these phenomena must be accounted for in some other way. Somatology
proves the unity of the human species; that is, the evidence upon which
this conclusion is reached is morphologic; but in arts, customs,
institutions, and traditions abundant corroborative evidence is found.
The individuals of the one species, though inhabiting diverse climes,
speaking diverse languages, and or