natural philosophy" and "natural religion." The second part, however,
written apparently not too long before publication, has a great deal to
do with medicine and constitutes one of the important medical documents
of the century.

Deserving of mention is an earlier and minor work of Boyle, indeed, his
first published writing, only recently identified. This work, apparently
written in 1649, bore the title "An Invitation to a free and generous
communication of Secrets and Receits in Physick," and appeared
anonymously in 1655 as part of a volume entitled _Chymical, Medicinal
and Chirurgical Addresses Made to Samuel Hartlib, Esquire_.[40] For our
purposes, it is significant as emphasizing his early interest in
medicine.

Boyle seems to have acquired most of his medical knowledge between, say,
1649 and 1662. It is worth recalling some of the trends and conflicts
that formed the medical environment during this period. Among the major
trends, first place, perhaps, must be given to Galenic doctrine, which
had come under progressively severe attack. Moliere, who lived from 1622
to 1673, showed in his comedies the popular reaction to a system which,
although dominant, was clearly crumbling. The cracks in the edifice even
the layman could readily see. Nevertheless, Galenism had its strong
supporters. Riverius, who lived from 1589 to 1655, was a staunch
Galenist. An edition of his basic and clinical works[41] was translated
into English in 1657, and Latin editions continued to be published well
into the eighteenth century.[42]

Galenism, of course, had to withstand the great new discoveries in
anatomy and physiology made by Vesalius, Aselli, Sanctonius, Harvey, and
others, not to mention the host of great investigators who were more
strictly contemporaries of Boyle.

Galenism also faced the rivalry of chemistry. The so-called "antimony
war" in the earlier part of the century marked an important assault on
Galenism, and the letters of the arch-conservative Guy Patin (who died
in 1672) help us appreciate this period.[43] However, even more
important was the work of van Helmont, who developed and extended the
doctrines of Paracelsus and represented a major force in
seventeenth-century thought. Boyle was well acquainted with the
writings of van Helmont, who, although his works fell into disrepute as
the mechanical philosophy gradually took over, nevertheless in the
middle of the seventeenth century was a highly significant figure.