Last Supreme Court justice that didn't go to law school?

Who was the last member of the United States Supreme Court who didn’t go to law school? At one time the norm was for aspiring lawyers to clerk in the offices of an experianced lawyer and then take the bar. Has a non-lawyer ever served on the court?

Henry Billings Brown never got a law degree, although he went to law school. Does that count?

James F. Byrnes never attended high school, college or law school. He was admitted to the bar in 1903 after apprenticing to a lawyer. He was a Supreme Court Justice in 1941-42.

The Wikipedia article on Stanley Forman Reed says:

Reed was a justice from 1938 to 1957, incidentally. He died in 1980.