The Coulter Principle: Foundation of an Industry

Introduced in the mid-1950s, the Coulter Principle became the foundation of an industry responding to the need for automated cell-counting instruments. The industry developed in three acts, as Wallace H. Coulter and his brother Joseph R. Coulter, Jr., developed the simple idea of passing cells through a sensing aperture. In Act I, Wallace’s desire to automate the routine erythrocyte count led to a simple idea, the definition of the Coulter Principle, its patenting, its acceptance by the National Institutes of Health, and its description at a national conference. In Act II, the Coulter brothers addressed the practicalities of a commercial instrument and of a business organization to support its manufacture and sale. In Act III, a broad research effort developed regarding volumetric errors originating in functional characteristics of the sensing aperture, and the brothers’ growing organization found solutions permitting introduction of increasingly automated hematology analyzers. Today the industry thrives, with several participants.