Mary's friends

[Susan Higginbotham]

According to the granddaughter, Mary continued to write to Myra after her return from Europe, but the granddaughter declined to publish the letters, which she described as sweet and chatty, and they apparently have not survived or have not been found.

Any chance Robert Lincoln got hold of them somehow? IMO he burned a lot of his mother's letters.

Not in this case, as RTL was dead at the time Myra's granddaughter (Myra Helmer Pritchard) was writing, and the manuscript indicates that Pritchard had the later letters but chose deliberately not to include them.