The cause of this susceptibility in the morning is not difficult to be discovered. Not only have the stomach, duodenum, and upper intestine, been entirely empty for several hours, but the absorbents and other parts engaged in the function of alimentation have likewise been in a state of repose, and now awake, refreshed, and ready for action. A considerable exhalation from the skin and lungs has, at the same time, been going on; which, taken along with the deposition of new particles to the existing organization, necessarily reduces the quantity and quality of the circulating fluids, and thereby communicates a stimulus to the absorbents which fits them for imbibing that nourishment, of which the system stands peculiarly in need, but which, where legitimate food is denied to them, equally excites them to imbibe any morbid agent which may happen to solicit their action. The great loss of fluid by exhalation during the night, and the consequent demand for liquids in the morning, explain why our first daily meal is almost universally of a more fluid and less substantial description than any of the subsequent ones; while our active exertion and loss of solids during the day create a proportionate demand for a more substantial repast in the afternoon. The function of absorption then is at its highest pitch of activity in the morning, simply because every part of the frame is craving for a supply to repair the losses which it has sustained; and if the body be exposed to miasma or other impurities, they will be much more easily and speedily absorbed by the skin, the pulmonary membrane, and the stomach, before eating than after the absorbents have been supplied with their legitimate food. This is the true theory of the greater susceptibility of infection and other poisonous influences when the stomach is empty.