Robert Todd Lincoln --The vitals

[AussieMick]

Infuriatingly, "no" .... Keneally only says "by June 1861 on top of his other causes for grief, Lincoln received an anonymous letter about Mary's relationship with Wood, implying it was adulterous.'
Keneally's sources are (for what they are worth) say 'on the fascinating subject of Lincoln's marriage ... apart from Herndon and other sources, we have Katherine Helm's The true Story of Mary Lincoln ... , 1928,. also, Ruth Painter Randall's Mary Lincoln: ..., and Mary Lincoln : A Biography, by Jean Baker.
Which one of these he uses for the anonymous letter reference, he doesnt say.