lly appealed to
by anthropologists as contributing to the following lines of argument. A
primary mental similarity of all branches of the human race is evidenced
by their common faculty of speech, while at the same time secondary
diversities of race-character and history are marked by difference of
grammatical structure and of vocabularies. The existence of groups or
families of allied languages, each group being evidently descended from
a single language, affords one of the principal aids in classifying
nations and races. The adoption by one language of words originally
belonging to another, proving as it does the fact of intercourse between
two races, and even to some extent indicating the results of such
intercourse, affords a valuable clue through obscure regions of the
history of civilization.

Communication by gesture-signs, between persons unable to converse in
vocal language, is an effective system of expression common to all
mankind. Thus, the signs used to ask a deaf and dumb child about his
meals and lessons, or to communicate with a savage met in the desert
about game or enemies, belong to codes of gesture-signals identical in
principle, and to a great extent independent both of nationality and
education; there is even a natural syntax, or order of succession, in
such gesture-signs. To these gestures let there be added the use of the
interjectional cries, such as _oh! ugh! hey!_ and imitative sounds to
represent the cat's _mew_, the _click_ of a trigger, the _clap_ or
_thud_ of a blow, &c. The total result of this combination of gesture
and significant sound will be a general system of expression, imperfect
but serviceable, and naturally intelligible to all mankind without
distinction of race. Nor is such a system of communication only
theoretically conceivable; it is, and always has been, in practical
operation between people ignorant of one another's language, and as such
is largely used in the intercourse of savage tribes. It is true that to
some extent these means of utterance are common to the lower animals,
the power of expressing emotion by cries and tones extending far down in
the scale of animal life, while rudimentary gesture-signs are made by
various mammals and birds. Still, the lower animals make no approach to
the human system of natural utterance by gesture-signs and
emotional-imitative sounds, while the practical identity of this human
system among races physically so unlike as the Englishman