digestion, and show that it is neither a mechanical power, nor
contractions of the stomach, nor heat, but something secreted in
the coats of the stomach, and thrown into its cavity, which there
animalizes the food or assimilates it to the nature of the blood.
The power of this juice is confined or limited to certain
substances, especially of the vegetable and animal kingdoms; and
although this menstruum is capable of acting independently of the
stomach, yet it is indebted to that viscus for its
continuance.[5]


THE FUNCTION OF RESPIRATION

It is a curious commentary on the crude notions of mechanics of
previous generations that it should have been necessary to prove
by experiment that the thin, almost membranous stomach of a
mammal has not the power to pulverize, by mere attrition, the
foods that are taken into it. However, the proof was now for the
first time forthcoming, and the question of the general character
of the function of digestion was forever set at rest. Almost
simultaneously with this great advance, corresponding progress
was made in an allied field: the mysteries of respiration were
at last cleared up, thanks to the new knowledge of chemistry. The
solution of the problem followed almost as a matter of course
upon the advances of that science in the latter part of the
century. Hitherto no one since Mayow, of the previous century,
whose flash of insight had been strangely overlooked and
forgotten, had even vaguely surmised the true function of the
lungs. The great Boerhaave had supposed that respiration is
chiefly important as an aid to the circulation of the blood; his