ny people after a full supper are, I believe, owing to
this cause. The supper occasions no inconvenience, whilst the person is
upright and awake; but, when he lies down and begins to sleep,
especially if he does not perspire, the symptoms above mentioned occur.
Which may be thus explained in part from your principles. When the
power of volition is abolished, the other sensorial actions are
increased. In ordinary sleep this does not occasion increased frequency
of the pulse; but where sleep takes place during the process of
digestion, the digestion itself goes on with increased rapidity. Heat
is excited in the system faster than it is expended; and operating on
the sensitive actions, it carries them beyond the limitation of
pleasure, producing, as is common in such cases, increased frequency of
pulse.

"It is to be observed, that in speaking of the heat generated under
these circumstances, I do not allude to any chemical evolution of heat
from the food in the process of digestion. I doubt if this takes place
to any considerable degree, for I do not observe that the parts
incumbent on the stomach are increased in heat during the most hurried
digestion. It is on some parts of the surface, but more particularly on
the extremities of the body, that the increased heat excited by
digestion appears, and the heat thus produced arises, as it should
seem, from the sympathy between the stomach and the vessels of the
skin. The parts most affected are the palms of the hands and the soles
of the feet. Even there the thermometer seldom rises above 97 or 98
degrees, a temperature not higher than that of the trunk of the body;
but three or four degrees higher than the common temperature of these
parts, and therefore producing an uneasy sensation of heat, a sensation
increased by the great sensibility of the parts affected.

"That the increased heat excited by digestion in sleep is the cause of
the accompanying fever, seems to be confirmed by observing, that if an
increased expenditure of heat accompanies the increased generation of
it (as when perspiration on the extremities or surface attends this
kind of sleep) the frequent pulse and flushed countenance do not occur,
as I know by experiment. If, during the feverish sleep already
mentioned, I am awakened, and my attention engaged powerfully, my pulse