For key sources (and relevant commentary) for the history of evidence based medicine:
For the text of John Snow on Cholera (1855):
For an electronic library of medical history texts:
For early modern anatomy illustrations:
Jeremy Norman's historyofscience.com:
To purchase copies of Bad Medicine: Doctors Doing Harm Since Hippocrates: http://www.oup.co.uk/isbn/0-19-280355-7
Alternatively, visit www.bookfinder.com to find the best price, new or secondhand.
David Wootton's page at the University of York (includes list of other publications):