After completing his MSc and PhD, Bruce undertook a two-year postdoctoral fellowship with Ciba Biological Research Laboratories, a pharmaceutical company located in Basel, Switzerland. He learned to speak German and sailed on MS Achille Lauro to Genoa, Italy, before taking the train to Basel. It was an 'immensely interesting' time. The company not only gave him a lot of freedom with his research but he also gained exposure to leading international scientists for whom Switzerland was a popular holiday destination. Bruce had also contacted research institutes in the United States for postdoctoral opportunities. Yet, 'I found out that if I went on an immigration visa to the States I could be eligible for drafting [for the Vietnam War], and that really influenced my decision to go to Europe'. During the second year of his fellowship, he received an invitation from Bruce Cain to join the Auckland Cancer Research Laboratory. He discusses his work with Bruce Cain following his return to New Zealand in 1968. His work also involved collaborating with clinicians, especially hematologist John Buchanan, to collect blood samples from patients at Auckland Hospital to test how they responded to an anti-cancer drug.