Hi Ian,
would that be Rachel Mendes da Costa (an only child), born in Curacao 12-01-1835 to Obadiah Mendes da Costa of London and Eliza of Jacob Brandon (also from London) but married in New York in 1833.
Rachel married 17-09-1851 in Curacao to the physician Isaac de Jacob Senior. The couple had 7 children in Curacao. Among them Jacob, born 04-06-1854 and married to Clara de Abraham Jesurun on 03-07-1882 in Curaçao. Brother Arthur was born 25-12-1867 and I have no Curaçao marriage for him. Do you know where the brother's received their dentist's training? The were all jewish.