, he always excepted the soul of man, as outside
his investigations.

But while Boyle was a skillful chemist, judged by the standards of his
time, we cannot call him a skillful medical investigator. This
represents, however, the fault of the era in which he lived rather than
any fault peculiar to him. Boyle's medical studies fall into at least
two categories. These were the purely physiological experiments, such as
those on respiration or on blood, and the more clinical experiments,
concerned with pharmaceuticals, clinical pharmacology, and clinical
medicine. The purely physiological experiments have great merit and were
profoundly influential in shaping modern physiology. The clinical
experiments throw great light on the development of critical judgment in
medical history, and the relations of judgment and faith.

In 1775, John Hunter wrote a letter to Jenner that has become quite
famous. Hunter had just thanked Jenner for an "experiment on the
hedgehog." But, continued Hunter, "Why do you ask me a question by way
of solving it? I think your solution is just, but why think? Why not try
the experiment?"[50] The word "just," of course, in its
eighteenth-century sense, means exact or proper, precise or correct. A
"just solution" is one that is logically correct. The "think" refers to
Hunter's own uncertainty. He is not content with a verbal or logical
solution to a problem, he wants empirical demonstration. Why, he is
asking, should we be content with merely a logically correct solution
when we can have an experiential demonstration. _Try the experiment._
Put the logical inference to the test of experience.

This empirical attitude, not at all infrequent in the latter
eighteenth-century medicine, was quite unusual in the seventeenth-century
medicine. This was precisely the attitude that Robert Boyle exhibited in
his clinical contacts.

Medicine, at least textbook medicine, was rationalistic. Textbooks
started with definitions and assertions regarding the fundamentals of
health. This we see particularly in a Galenic writer such as Riverius.
Medicine, he said, "stands upon the basis of its own principles, axioms
and demonstrations, repeated by the demonstration of nature."[51] In his
text, Riverius first expounded a groundwork concerning the elements,
temperaments and humors, spirits and innate heat, the faculties and
functions; then the nature of the diseases which resulted from
disturbances of these; and finally the s