Levi-Montalcini accepted an invitation to conduct her research at a neurological institute in Belgium. But, fearing for her family, she soon returned to Turin—just before Mussolini and Hitler forged their alliance. Undeterred, Levi-Montalcini continued her research: “I immediately found a way to establish a laboratory in my bedroom.” In the years that followed, bombs fell repeatedly, and again and again she would lug her microscope and slides to safety in the basement.
In spite of the hardship—or perhaps, as Levi-Montalcini sees it, because of the adversity—it was during this time that she laid the groundwork for her later investigation of nerve growth factor. “You never know what is good, what is bad in life,” she muses. “I mean, in my case, it was my good chance.” Levi-Montalcini and her family left Turin in 1942 for the surrounding hills and successfully survived the war in hiding. By convincing farmers that she needed eggs for her children (whom she did not have), Levi-Montalcini studied how embryonic nerve tissue differentiates into specialized types. The prevailing theory, developed by renowned biologist Viktor Hamburger of Washington University, held that the differentiation, or specialization, of nerve cells depends in large part on their destination. In his experiments, Hamburger removed developing limbs in chick embryos to see how such excision would affect the later growth and differentiation of the nerve cells destined for that region of the embryo.