o one can contemplate the facts we have cited in illustration of the
early stages of science, without recognising the _necessity_ of the
processes through which those stages were reached--a necessity which, in
respect to the leading truths, may likewise be traced in all after
stages. This necessity, originating in the very nature of the phenomena
to be analysed and the faculties to be employed, more or less fully
applies to the mind of the child as to that of the savage. We say more
or less fully, because the correspondence is not special but general
only. Were the _environment_ the same in both cases, the correspondence
would be complete. But though the surrounding material out of which
science is to be organised, is, in many cases, the same to the juvenile
mind and the aboriginal mind, it is not so throughout; as, for instance,
in the case of chemistry, the phenomena of which are accessible to the
one, but were inaccessible to the other. Hence, in proportion as the
environment differs, the course of evolution must differ. After
admitting sundry exceptions, however, there remains a substantial
parallelism; and, if so, it becomes of great moment to ascertain what
really has been the process of scientific evolution. The establishment
of an erroneous theory must be disastrous in its educational results;
while the establishments of a true one must eventually be fertile in
school-reforms and consequent social benefits.

[1] _British Quarterly Review_, July 1854.

[2] It is somewhat curious that the author of _The Plurality of Worlds_,
with quite other aims, should have persuaded himself into similar
conclusions.

ON THE PHYSIOLOGY OF LAUGHTER[1]

Why do we smile when a child puts on a man's hat? or what induces us to
laugh on reading that the corpulent Gibbon was unable to rise from his
knees after making a tender declaration? The usual reply to such
questions is, that laughter results from a perception of incongruity.
Even were there not on this reply the obvious criticism that laughter
often occurs from extreme pleasure or from mere vivacity, there would
still remain the real problem--How comes a sense of the incongruous to
be followed by these peculiar bodily actions? Some have alleged that
laughter is due to the pleasure of a relative self-elevation, which we
feel on seeing the humiliation of others. But this theory, whatever
portion of truth it may contain, is, in the first place, open to the
fatal objectio