Returning to Japan after marrying Jean Clark in 1937, Dan used advanced light microscopy and direct observation of cell behavior to learn especially about fertilization, development, and morphogenesis. He encouraged his student Shinya Inoué to construct and improve the polarized light microscope to investigate the existence of spindle fibers in the mitotic apparatus, a structure that coordinates the accurate segregation of chromosomes during cell division.

Katsuma Dan came to MBL in 1931 while he was a graduate student at the University of Pennsylvania with Victor Heilbrunn. He studied fundamental questions in cell biology and embryonic development using a number of marine invertebrates as model organisms.

Dan and his daughter
Dan and his daughter, 1952

1. Still Image: "Katsuma Dan", 6/11/2012, https://hdl.handle.net/1912/16827

2. Still Image: "Katsuma Dan and his daughter", 6/11/2012, https://hdl.handle.net/1912/22722.