THOMAS HENRY (1825-1895).-Scientific writer, _s._ of an assistant master in a public school, was _b._ at Ealing. From childhood he was an insatiable reader. In his 13th year he became a medical apprentice, and in 1842 entered Charing Cross Hospital. Thereafter he was for a few months surgeon on board the _Victory_ at Haslar, and was then appoi