Rarely in the history of constitutional medicine and human genetics has the discovery of a single laboratory technique stimulated such an astonishing advance in the knowledge of human variation as did the perfection of human chromosome techniques. The only comparable phenomenon was occasioned by Smithies' starch-gel electrophoresis and, before that, by the discovery of the blood groups. The application of the latter two methods to the study of human illness brought immediate results and initiated a fundamental revolution in the knowledge of human variation, molecular biology, and biochemical genetics. In human cytogenetics this revolution has not materialized, in spite of the almost universal dissemination of knowledge of chromosomes and the publication of thousands of papers on the subject during the past half-dozen years.
At the present time, human cytogenetics is in a state comparable to biology in the days of Linnaeus. The overwhelming number of published papers report one or