aid down*; and as
regards diet, sleep, and exercise, habit may render the most unlike
methods and times equally safe and beneficial. But wholesome food in
moderate quantity, sleep long enough for rest and refreshment, exercise
sufficient to neutralize the torpifying influence of sedentary pursuits,
and these, though not with slavish uniformity, yet with a good degree of
regularity, may be regarded as essential to a sound working condition of
body and mind. The same may be said of the unstinted use of water, which
has happily become a necessity of high civilization, of pure air, the
worth of which as a sanitary agent is practically ignored by the major
part of our community, and of the direct light of heaven, the exclusion of
which from dwellings from motives of economy, while it may spare carpets
and curtains, wilts and depresses their owners. These topics are inserted
in a treatise on ethics, because whatever has a bearing on health, and
thus on the capacity for usefulness selfward and manward which constitutes
the whole value of this earthly life, is of grave moral significance. If
the preservation of life is a duty, then all hygienic precautions and
measures are duties, and as such they should be treated by the individual
moral agent, by parents, guardians, and teachers, and by the public at
large.

*Self-preservation is endangered by poverty.* In the lack or
precariousness of the means of subsistence, the health of the body is
liable to suffer; and even where there is not absolute want, but a
condition straitened in the present and doubtful as to the future, the
mind loses much of its working power, and life is deprived of a large
portion of its utility. Hence the duty of industry and economy on the part
of those dependent on their own exertions. It is not a man's duty to be
rich, though he who in acquiring wealth takes upon himself its due
obligations and responsibilities, is a public benefactor; but it is every
man's duty to shun poverty, if he can, and he who makes or keeps himself
poor by his own indolence, thriftlessness, or prodigality, commits a sin
against his own life, which he curtails as to its capacity of good, and
against society, which has a beneficial interest in the fully developed
life of all its members.

Section II.

The Attainment Of Knowledge.

Inasmuch as knowledge, real or supposed, must needs precede every act of
the will, and as the adaptation of