re of themselves, and their final
enunciation will be in the hands of men more competent than the writer
will ever pretend to be, although his knowledge, after careful study
of all data attainable, may be considerably increased. The mere
collection of facts, however, cannot be prosecuted to advantage
without predetermined rules of judgment, nor can they be classified at
all without the adoption of some principle which involves a tentative
theory. More than a generation ago Baader noticed that scientific
observers only accumulated great masses of separate facts without
establishing more connection between them than an arbitrary and
imperfect classification; and before him Goethe complained of the
indisposition of students of nature to look upon the universe as a
whole. But since the great theory of evolution has been brought to
general notice no one will be satisfied at knowing a fact without also
trying to establish its relation to other facts. Therefore a working
hypothesis, which shall not be held to with tenacity, is not only
allowable but necessary. It is also important to examine with proper
respect the theories advanced by others. Some of these, suggested in
the few publications on the subject and also by correspondents, will
be mentioned.

_NOT CORRELATED WITH MEAGERNESS OF LANGUAGE._

The story has been told by travelers in many parts of the world that
various languages cannot be clearly understood in the dark by their
possessors, using their mother tongue between themselves. The evidence
for this anywhere is suspicious; and when it is asserted, as it
often has been, in reference to some of the tribes of North American
Indians, it is absolutely false, and must be attributed to the error
of travelers who, ignorant of the dialect, never see the natives
except when trying to make themselves intelligible to their visitors
by a practice which they have found by experience to have been
successful with strangers to their tongue, or perhaps when they are
guarding against being overheard by others. Captain Burton, in his
_City of the Saints_, specially states that the Arapahos possess a
very scanty vocabulary, pronounced in a quasi-unintelligible way, and
can hardly converse with one another in the dark. The truth is that
their vocabulary is by no means scanty, and they do converse with each
other with perfect freedom without any gestures when they so please.
The difficulty in speaking or understanding their langua