During experiments carried out from 1940 to 1960, her scientific hypotheses did not require highly sophisticated techniques. Indeed, Rita’s and Stanley Cohen’s use of NGF antibodies in 1960 gave rise to identical results as did NGF knockout mice generated more than 40 years later. Interestingly, most of her experiments did not contain statistical data.
Rita did not like results based on a statistical analysis and, as she used to say, she preferred “experiments with a yes or no answer
After the award, she wrote that NGF had an “organismic role” that was more extended than the basis of the Nobel prize, which was on the discovery of growth factors. Studies since then confirm an extended role of neurotrophic factors, not only in peripheral and central nervous system, but also in the immune and endocrine system. Her predictions anticipated the demonstration that NGF plays an important role in aggressive behavior, learning and memory, fertility, pain, and neuronal plasticity.
She apparently discovered also the principle of apoptosis many decades before the concept emerged:
Rita possessed a very gracious but assertive personality. We recall a lunch more than 15 years ago when Rita proclaimed that she had originally discovered cell death in the 1940s. This was difficult to fathom because apoptosis was originally coined as a term in 1972. But in fact, Rita and her famous teacher in medical school, Giuseppe Levi, described a spontaneous form of neuronal death in the chick embryo, which was published by the Academia Pontificia Scientiarum in 1944 (Levi-Montalcini and Levi, 1944). This paper was not widely read because it was printed by a religious institution, as a result of a law stated by Mussolini in 1938 prohibiting academic and professional careers to those of Jewish descent. Also, the abstract was unconventional in that it appeared in Latin, “Extirpato, ex pulli gallinacei fetu, tertio incubationis die…”
R. Levi-Montalcini, G. Levi. Correlazioni nello sviluppo tra varie parti del sistema nervoso. Pontificia Academia Scientiarum. Commentationes, vol. VIII (1944), pp. 527–568