Langdon Clemens, SLC’s first child and only son, was born prematurely and was not expected to live. During his 19 months of life he was constantly ill, and never learned to walk. He died in June 1872 of diphtheria. In an autobiographical dictation of March 1906, SLC blamed himself for the death, claiming he had inadvertently exposed Langdon to the cold weather during a morning carriage drive.