« It takes a plague to know a plague » may be said both of the prin­ciple of ino­cu­la­tion and of the his­to­rio­gra­phy of epi­de­mics. Certainly this was true of Daniel Defoe’s book, The Journal of the Plague Year, which was osten­si­bly about the Great Plague of London in 1665 but which actual­ly was contri­bu­tion to the plan­ning of the plague in 1721 when both the bubo­nic plague and the small­pox re-appea­red in Europe and the wes­tern Atlantic. In 1721 the bubo­nic plague appea­red in Marseilles where it was met with reli­gious pie­ty and repres­sive qua­ran­tine. In the Dutch ports car­goes were…