She wrote a book, "Spring in a small island" in 1938, about her experiences in persuading leprosy patients in remote areas of Japan into hospitalization.

In this book, she wrote her experiences in her trips of examination of leprosy patients in remote mountainous areas and islands.

They brought a projector to show village people that leprosy patients should be treated in sanatoriums.

Eiko Arai coined a word "Spring in a small island" phenomenon, explaining the wave of support concerning Masako Ogawa.

She reported that pregnancy worsened leprosy, and tried to justify the segregation, which her teacher, Mitsuda, firmly believed.