hen descends, through the oesophagus, into the
stomach, where it becomes digested, and, in a great measure,
dissolved, by the gastric juice, which is secreted by the arteries of
the stomach. It is then pushed through the pylorus, or right orifice
of the stomach into the duodenum, where it becomes mixed with the
bile from the gall bladder and liver, and the pancreatic juice from
the pancreas. These fluids seem to complete the digestion: after
this, the food is continually moved forwards by the peristaltic
motion of the intestines.

The chyle, or thin and milky part of the aliment, being absorbed by
the lacteals, which rise, by open mouths, from the intestines, is
carried into the receptacle of the chyle, and from thence the
thoracic duct carries it to the subclavian vein, where it mixes with
the blood, and passes with it to the heart.

The food of animals is derived from the animal or vegetable kingdoms.
There are some animals which eat only vegetables, while others live
only on animal substances. The number and form of the teeth, and the
structure of the stomach, and bowels, determine whether an animal be
herbivorous, or carnivorous. The first class have a considerable
number of grinders, or dentes molares; and the intestines are much
more long and bulky; in the second class, the cutting teeth are
predominant, and the intestines are much shorter.

Man seems to form an intermediate link between these two classes: his
teeth, and the structure of the intestines, show, that he may subsist
both on vegetable and animal food; and, in fact, he is best nourished
by a proper mixture of both. This appears from those people who live
solely on vegetables, as the Gentoo tribes, and those who subsist
solely on animals, as the fish eaters of the northern latitudes,
being a feebler generation than those of this country, who exist on a
proper mixture of both. A due proportion, therefore, of the two kinds
of nourishment, seems undoubtedly the best.

Having taken a general view of the course of the aliment into the
blood, I shall now examine more particularly, how each part of the
organs concerned in digestion, or connected with that function,
contributes to that end.

The food being received into the mouth, undergoes various
preparations, which fit it for those changes it is afterwards to
undergo. By the teeth the parts of it are divided and ground,
softened and liquified by the saliva, and properly compressed by the
action of the