s diminished, a torpor is liable to ensue; that is, we take cold.
Hence people who sleep in the open air, generally feel chilly both at the
approach of sleep, and on their awaking; and hence many people are
perpetually subject to catarrhs if they sleep in a less warm head-dress,
than that which they wear in the day.

16. Not only the sensorial powers of irritation and of sensation, but that
of association also appear to act with greater vigour during the suspension
of volition in sleep. It will be shewn in another place, that the gout
generally first attacks the liver, and that afterwards an inflammation of
the ball of the great toe commences by association, and that of the liver
ceases. Now as this change or metastasis of the activity of the system
generally commences in sleep, it follows, that these associations of motion
exist with greater energy at that time; that is, that the sensorial faculty
of association, like those of irritation and of sensation, becomes in some
measure accumulated during the suspension of volition.

Other associate tribes and trains of motions, as well as the irritative and
sensitive ones, appear to be increased in their activity during the
suspension of volition in sleep. As those which contribute to circulate the
blood, and to perform the various secretions; as well as the associate
tribes and trains of ideas, which contribute to furnish the perpetual
dreams of our dreaming imaginations.

In sleep the secretions have generally been supposed to be diminished, as
the expectorated mucus in coughs, the fluids discharged in diarrhoeas, and
in salivation, except indeed the secretion of sweat, which is often visibly
increased. This error seems to have arisen from attention to the excretions
rather than to the secretions. For the secretions, except that of sweat,
are generally received into reservoirs, as the urine into the bladder, and
the mucus of the intestines and lungs into their respective cavities; but
these reservoirs do not exclude these fluids immediately by their stimulus,
but require at the same time some voluntary efforts, and therefore permit
them to remain during sleep. And as they thus continue longer in those
receptacles in our sleeping hours, a greater part is absorbed from them,
and the remainder becomes thicker, and sometimes in less quantity, though
at the time it was secreted the fluid was in greater quantity than in our
waking hours. Thus the urine is higher coloured after lo