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The Coulter Principle: For the Good of Humankind (Thesis by Marshall Graham)

Abstract
The atomic bombings of Hiroshima and Nagasaki in August 1945 made Wallace H. Coulter abruptly comprehend the critical need for rapid and accurate blood-cell counts in providing care for victims of radiation exposure. This thesis documents the unwritten story of his journey from that comprehension through his invention and implementation of the Coulter Principle, its commercialization in the first widely available automated blood-cell counter, and elaboration of that ground-breaking counter into increasingly sophisticated instrumentation for analysis not only of blood cells, but of particles involved in many other scientific disciplines. International cold-war politics and the burgeoning of increasingly powerful nuclear weapons were important motivations for him throughout the period here considered; these are summarized as context for his developmental activities.

The Coulter Principle states that if a suspension of blood cells is passed through a small restriction simultaneously with an electric current, the cells will modulate the current, so enabling them to be counted and sized. Today, hematology analyzers based on the Coulter Principle daily process blood samples from many more patients than the number of casualties from the Hiroshima and Nagasaki bombings.