In 1938 he transmitted to the Evian Conference the infamous offer by the German government to sell the Austrian Jews at a price of $250 per capita to any foreign country that would accept them and pay.
[2] This offer - and the Conference delegates' refusal to accept it - is the focal point of Hans Habe's novel The Mission (1965).
Already whilst a student he concerned himself with work on the normal and pathological anatomy of the ear in Anton Weichselbaum’s institute.
He subsequently worked in Adam Politzer's private laboratory, and in 1900 he entered the university ear clinic, becoming assistant in 1903.
From 1910 on he was the ear surgeon at the Spital der Kaufmannschaft (Merchants' Hospital), and from 1912 on head of the otology department of the Franz-Josef-Ambulatorium.
In 1919 he became professor extraordinary and head of the university clinic for diseases of the ear, nose and larynx, succeeding Viktor Urbantschitsch.
[3] Years prior to the Anschluss, in 1935, he was contacted by Nazi Party doctors about a larynx problem that Adolf Hitler was suffering from.
Prof. Dr. von Neumann, as he was by then known, refused to consider Hitler's case, explaining in his reply, that if the operation failed, it "might be construed as being connected with the fact that he is a Jew.
Neumann was particularly recognized for his works on painless operations on bone without anaesthetics, on the clinics and pathology of intracranial complications of infections of the middle ear, equilibrium, and otosclerosis.