His father was a thoughtful man of few words. A man who learned to read in night school. Who then went into business for himself as a brick maker, where he was known to have a strong propensity for math. He could estimate the number of bricks needed for any size contract with amazing accuracy. And he was a righteous man. The men who worked for him never used profanity in his presence. Not because he forbade it, but because they held him in high regard.
Then there was his maternal grandfather who was freed as a young man. “He was useless to his master because he viciously resisted his masters attempt to bend [his] will.” Slavery was not justifiable in his mind.
And then there was his paternal grandfather, who bought his and his wife’s freedom.
Nathan Francis Mossell came from a lineage of people who fought to overcome adversity. And he followed in their path. In 1882, he became the first African-American graduate of the University of Pennsylvania School of Medicine.
Source (some text directly for first paragraph): http://www.archives.upenn.edu/…/moss…/mossell_nf_autobio.pdf