Be that as it may, the preparation of chyle appears to be the true object of digestion, and as soon as it mingles with the circulation, the individual becomes aware of a great increase of physical power.
The digestion of fluids is less complicated than that of solids, and can be explained in a few words.
The purely liquid portion is absorbed by the stomach, and thrown into circulation; thence it is taken to the veins by the arteries and filtered by urethras, [Footnote: These urethras are conduits of the size of a pea, which start from the kidneys, and end at the upper neck of the bladder.] which pass them as urine, to the bladder.
When in this last receptacle, and though restrained by the spinchter muscle, the urine remains there but a brief time; its exciting nature causes a desire to avoid it, and soon voluntary constriction emits it through canals, which common consent does not permit us to name.
Digestion varies in the time it consumes, according to the temperament of individuals. The mean time, however, is seven hours, viz., three hours for the stomach, and the rest of the time for the lower intestines.
From this expose which I have selected from the most reliable authors, I have separated all anatomical rigidities, and scientific abstractions. My readers will thence be able to judge where the last meal they ate is: viz., during the first three hours in the stomach, later in the intestinal canal, and after seven hours, awaiting expulsion.
INFLUENCE OF DIGESTION.
Of all corporeal operations, digestion is the one which has the closest connection with the moral condition of man.
This assertion should amaze no one; things cannot be otherwise.
The principles of physiology tells us that the soul is liable to impressions only in proportion as the organs subjected to it have relation to external objects, whence it follows that when these organs are badly preserved, badly restored, or irritated, this state of degradation exerts a necessary influence on sensations, which are the intermediates of mental operations.