After taking his BA at the University of Alabama, Robertson gained his MD at Harvard and then went on to do a PhD at the Massachusetts Institute of Technology in the laboratory of F.O. Schmitt, the distinguished professor of electron microscopy. There he worked on the structure of nerve fibres. The conduction of signals along nerves depends upon the electrical properties of a thin surrounding membrane. He demonstrated how the arrangement of fatty molecules in this membrane shows three layers when seen by the electron microscope. This appearance of the "Robertson Unit Membrane" has become the classic evidence of the surface of a nerve fibre. There is a much thicker fatty sheath around some nerve fibres, helping them to conduct swiftly. He and others showed that these myelin sheaths are formed by folding around these fibres of the membranes of the surrounding sheath cells.
In the early 1950s I persuaded Robertson to join the Anatomy Department of University College, London. There he set up an electron microscopy department and trained many of those who later became active in this field. He brought his wife and young family to London where they stayed for five years.
After returning to the United States in 1959 he later became Head of the Anatomy Department of Duke University, in North Carolina. Here he ran a very active and thriving department, and we frequently met at the Duke laboratory for research and exchange of ideas. His later work was largely on the synaptic junctions between nerve cells. Changes in the synapses are believed to be an essential basis of memory. He produced evidence that there are changes in the structure of the cells in some parts of the brain of an octopus after learning. This work was done at the Duke University Marine Laboratory at Beaufort, NC, in a laboratory he set up for training these animals. He continued to work on this subject in spite of illness and he was still exchanging ideas with scientific visitors almost up to the end.
Always known by we English as Dave, but as David in America, he was a sociable character as well as a dedicated biologist. He and his family made many long-lasting friends during their time in London, my family in particular, and we always remained in close touch. They spent frequent summers in Naples, when Dave was working at the Stazione Zoologica. There we all had some very happy times together. It was not generally known that during these periods in Naples Dave Robertson painted a number of pictures in oils in the naif style, and some very attractive paintings of the Bay of Naples at night are now at his home in Durham, North Carolina.
James David Robertson, biologist and anatomist, electron microscopist: born Tuscaloosa, Alabama 13 October 1922; married Doris (Dody) Kohler (one son; two daughters); died Durham, North Carolina 11 August 1995.