and that "an overflow of nerve-force undirected by any motive,
will manifestly take first the most habitual routes; and if these
do not suffice, will next overflow into the less habitual ones."
This law I believe to be of the highest importance in throwing
light on our subject.`

[8] `The Senses and the Intellect,' 2nd edit. 1864, pp. 96 and 288.
The preface to the first edition of this work is dated June, 1855.
See also the 2nd edition of Mr. Bain's work on the `Emotions and Will.'

[9] `The Anatomy of Expression,' 3rd edit. p. 121.

[10] `Essays, Scientific, Political, and Speculative,' Second Series,
1863, p. 111. There is a discussion on Laughter in the First Series
of Essays, which discussion seems to me of very inferior value.

[11] Since the publication of the essay just referred to,
Mr. Spencer has written another, on "Morals and Moral Sentiments,"
in the `Fortnightly Review,' April 1, 1871, p. 426. He has, also,
now published his final conclusions in vol. ii. of the second edit.
of the `Principles of Psychology,' 1872, p. 539. I may state,
in order that I may not be accused of trespassing on
Mr. Spencer's domain, that I announced in my `Descent of Man,'
that I had then written a part of the present volume: my first MS.
notes on the subject of expression bear the date of the year 1838.

All the authors who have written on Expression, with the exception
of Mr. Spencer--the great expounder of the principle of Evolution--
appear to have been firmly convinced that species, man of
course included, came into existence in their present condition.