Connecticut-born neurologist best known for popularizing the medical term neurasthenia, used to describe nerve weaknesses.
He worked as an assistant surgeon in the U.S. Navy during the American Civil War.
He was a harsh critic of Spiritualism and published a harsh critique of the concept, called The Psychology of Spiritism, in 1879.
His father Spencer was a Congregational minister.
He argued in favor of leniency towards the man who assassinated President James Garfield, citing the man's insanity.