generalisation on the causes, or origin, of the various movements of
Expression. In observing animals, we are not so likely to be biassed by
our imagination; and we may feel safe that their expressions are not
conventional.
From the reasons above assigned, namely, the fleeting nature of some
expressions (the changes in the features being often extremely slight);
our sympathy being easily aroused when we behold any strong emotion,
and our attention thus distracted; our imagination deceiving us, from
knowing in a vague manner what to expect, though certainly few of us
know what the exact changes in the countenance are; and lastly, even
our long familiarity with the subject, from all these causes combined,
the observation of Expression is by no means easy, as many persons,
whom I have asked to observe certain points, have soon discovered.
Hence it is difficult to determine, with certainty, what are the
movements of the features and of the body, which commonly characterize
certain states of the mind. Nevertheless, some of the doubts and
difficulties have, as I hope, been cleared away by the observation of
infants, of the insane, of the different races of man, of works of
art, and lastly, of the facial muscles under the action of galvanism,
as effected by Dr. Duchenne.
But there remains the much greater difficulty of understanding the
cause or origin of the several expressions, and of judging whether any
theoretical explanation is trustworthy. Besides, judging as well as we
can by our reason, without the aid of any rules, which of two or more
explanations is the most satisfactory, or are quite unsatisfactory, I
see only one way of testing our conclusions. This is to observe whether
the same principle by which one expression can, as it appears, be
explained, is applicable in other allied cases; and especially, whether
the same general principles can be applied with satisfactory results,
both to man and the lower animals. This latter method, I am inclined to
think, is the most serviceable of all. The difficulty of judging of the
truth of any theoretical explanation, and of testing it by some
distinct line of investigation, is the great drawback to that interest
which the study seems well fitted to excite.
Finally, with respect to my own observations, I may state that they
were commenced in the year 1838; and from that time to the present day,
I have occasionally attended to the subject. At the above date, I was
18