Weiss is remembered for pioneer systematic research of the spinal marrow, medulla oblongata and basal ganglia, and in 1881 showed a causal relationship between tetany and the removal of goitre. The eponymous "Weiss' sign" is named after him, which today is usually referred to as "Chvostek's sign". Among his written works is a treatise on tetany (Über Tetanie) that is included in Richard von Volkmann's Sammlung klinischer Vorträge.
A friend of Sigmund Freud, Weiss committed suicide on September 13, 1883 at the age of 32, shortly after returning from his honeymoon. A few months prior to his death, he was appointed head of the outpatient clinic for nervous diseases at Vienna General Hospital.
- Weiss N. Centralbl Gesammt Ther 1883;1:9.
-  Freud 2000 by Anthony Elliott