On reaching his sixteenth year he began his studies at the University of Berlin, paying special attention to theology and the Talmud. He also mastered the English language and studied English literature. In 1855 Deutsch was appointed assistant in the library of the British Museum. He worked intensely on the Talmud and contributed no less than 190 papers to Chambers' Encyclopaedia, in addition to essays in Kittos and Smiths' Biblical Dictionaries, and articles in periodicals. In October 1867 his article on The Talmud, published in the Quarterly Review, made him known. It was translated into French, German, Russian, Swedish, Dutch and Danish. He died at Alexandria on 12 May 1873.
His Literary Remains, edited by Lady Strangford, were published in 1874, consisting of nineteen papers on such subjects as The Talmud, Islam, Semitic Culture, Egypt, Ancient and Modern, Semitic Languages, The Targums, The Samaritan Pentateuch, and Arabic Poetry.