In 1911, Joseph Bailie, a professor at Nanjing University, often took his Chinese students to tour Nanjing's shantytowns. One student, the son of a district magistrate, followed Bailie from hut to hut one rainy day, and was grateful that Bailie opened his eyes to the poverty in his own city.

However, twenty years later, when M. R. Schafer, another Nanjing University professor, showed his students a film that included his own photographs of the poor quarters of Nanjing, his students were so upset that they demanded his expulsion from China.

Zwia Lipkin explores the reasons for these...