Poisoning Lincoln

[RJNorton]

Bill, here's another instance I don't see in most accounts. In Theodore Roscoe's The Web of Conspiracy, the author wrote, "One day (we are told) a woman spy disguised in widow's weeds, heavily veiled, walked into Lincoln's office and tried to poison him with a kiss. Smallpox. The story may be apocryphal, but the President did, in fact, contract a mild case of varioloid."

Does anyone know if the story is apocryphal? Has anyone seen it in another source other than Roscoe's book?