The medical dictionary can be found at
http://homepage.mac.com/sholland/contrivances/
The file downloadable from there is en-medical.rws
The file is 6.7 MB in size. It is both a general english dictionary and a
medical dictionary, combined.
You may to create or edit a .multi file for this to work. One very pleasant
and helpful fellow suggested that I just make the word list available so
people can compile their own dictionary.
Regarding the copyright, the folks at the NLM claim no copyright and provide
it for public use without restriction, except to say they do not want to be
credited as the source. As a list, it is not subject to copyright
restrictions. It is therefore public domain.