Good Reader,
Havingbeen hitherto very averse from Publishing any of Dr.Willis's Posthumous Works, because it may be presum'd that they want his last Hand to compleat them; and for that Reason, giving no ear till now to any Entreaties of that kind, though never so powerful, or never so importunate: I think my self oblig'd to give the World some Account why I alter'd my mind as to this particular, and did at length suffer my self to be prevail'd with to Print the following Treatise, it being now Fifteen Years after his Death; and it is briefly this: A worthy Friend and an old Acquaintance of mine, desiring if I knew of, or could procure any choice and approv'd Receipts against the Plague, that I would furnish him with some for a Friend of his, for the preservation of whose Health he had a singular concern, and who was going in the late Embassie toConstantinople, where that Distemper then was, and did frequently rage: I promis'd to use my utmost endeavours to supply him; and calling to mind this short Tract, which I transcrib'd from the Doctor's Papers in the Year 1666, being then hisAmanuensis; I knew it would far exceed whatsoever I could elsewhere obtain, or pretend to collect upon this Subject: Whereupon I allow'd him to take a Copy of it for his Friend's use, upon condition he would not make it publick. But not long since a suspicious Sickness having seiz'd their Majesties Army inIreland, the same Person was very much of opinion, that the Printing of it might do great service, should that Disease prove Pestilential; and urg'd such Arguments, as made me to be also of the same perswasion; especially, he having shew'd the Copy to several of the most eminent Physicians amongst us, whose opinion it was, as he assur'd me, that the Publishing of it might be of very great use, it being a charitable instruction in cases of great danger, for such as cannot procure the attendance of Physicians: I must needs own, that I could not withstand the judgment of such Persons.
The regard I have always had, and shall still have for the Reputation and Memory of my dearMaster, and bestFriend, will not, I presume, be thought to lessen, by my giving way upon these terms to this Publication; since it is so earnestly desir'd, and so well esteem'd of: And the Good that is aim'd at by it can be no ill Apology for
Thy Friend and Servant,
J. Hemming.
St.Martins-Lane,Sept. 1. 1690.