Several cases in physick, and one in particular, giving an account of a person who was inoculated for the small-pox and had the small-pox upon the inoculation, and yet had it again. Together with two or three other very remarkable small-pox cases, &c. To which is added, a letter to Dr. Lee, giving him an account of a letter of Dr. Freind's concerning that fever which infested the army in Spain; together with the said letter