it were a purely chemical process. He collected quantities
of gastric juice, and placing it in suitable vessels containing crushed
grain or flesh, kept the mixture at about the temperature of the body
for several hours. After repeated experiments of this kind, apparently
conducted with great care, Reaumur reached the conclusion that "the
gastric juice has no more effect out of the living body in dissolving
or digesting the food than water, mucilage, milk, or any other bland
fluid."(3) Just why all of these experiments failed to demonstrate a
fact so simple does not appear; but to Spallanzani, at least, they
were by no means conclusive, and he proceeded to elaborate upon the
experiments of Reaumur. He made his experiments in scaled tubes exposed
to a certain degree of heat, and showed conclusively that the chemical
process does go on, even when the food and gastric juice are removed
from their natural environment in the stomach. In this he was opposed
by many physiologists, among them John Hunter, but the truth of his
demonstrations could not be shaken, and in later years we find Hunter
himself completing Spallanzani's experiments by his studies of the
post-mortem action of the gastric juice upon the stomach walls.

That Spallanzani's and Hunter's theories of the action of the gastric
juice were not at once universally accepted is shown by an essay written
by a learned physician in 1834. In speaking of some of Spallanzani's
demonstrations, he writes: "In some of the experiments, in order to give
the flesh or grains steeped in the gastric juice the same temperature
with the body, the phials were introduced under the armpits. But this is
not a fair mode of ascertaining the effects of the gastric juice out of
the body; for the influence which life may be supposed to have on the
solution of the food would be secured in this case. The affinities
connected with life would extend to substances in contact with any part
of the system: substances placed under the armpits are not placed at
least in the same circumstances with those unconnected with a living
animal." But just how this writer reaches the conclusion that "the
experiments of Reaumur and Spallanzani give no evidence that the gastric
juice has any peculiar influence more than water or any other bland
fluid in digesting the food"(4) is difficult to understand.

The concluding touches were given to the new theory of digestion by
John Hunter, who, as we have seen, at first