separate item must have been successively present to consciousness,
though for a time too short to leave any memory. Sir W. Hamilton thinks
that the separate items may pass, and often do pass, unconsciously;
which opinion Mr Mill also, though not approving his reasons, is
inclined to adopt.

'I am myself inclined (p. 285) to admit unconscious mental
modifications, in the only sense in which I can attach any
very distinct meaning to them--namely, unconscious
modifications of the nerves. It may well be believed that
the apparently suppressed links in a chain of association,
those which Sir W. Hamilton considers as latent, really are
so: that they are not even momentarily felt, the chain of
causation being continued only physically--by one organic
state of the nerves succeeding another so rapidly, that the
state of mental consciousness appropriate to each is not
produced.'

Mr Mill gives various illustrations in support of this doctrine. He at
the same time calls attention to a valuable lecture of Sir W.
Hamilton's, the thirty-second lecture on Metaphysics; especially to the
instructive citation from Cardaillac contained therein, noting the
important fact, which descriptions of the Law of Association often keep
out of sight--that the suggestive agency of Association is carried on,
not by single antecedents raising up single consequents, but by a mass
of antecedents raising up simultaneously a mass of consequents, among
which attention is very unequally distributed.

We shall say little upon Mr Mill's remarks on Sir W. Hamilton's Theory
of Causation--(chap. xvi.). This theory appears to Mr Mill absurd; while