A treatise of the small-pox and measles; describing their nature, causes, and signs, diagnostick and prognostick, in a different way to what hath hitherto been known. Together, with the method of curing the said distempers, and all, or most, of the best remedies. Also, a particular discourse of opium, diacodium, and other sleeping medicines; with a reference to a very great case. By Gideon Harvey, M.D. His Majesties physician of the Tower and not of the college of physicians.