In 1937, the first report of the American Medical Association's Committee on Blood Grouping Tests was prepared and published. At that time, only the four A-B-O groups and three M-N types were in use. In 1952, a second report was published by the Association's Committee on Medicolegal Problems to cover the advances in the preceding 15-year interval, especially the Rh-Hr types. The developments that have occurred during the past four years necessitate a supplementary report, which appears on page 233 of this issue.
The new report includes a discussion of the nomenclature of the Rh-Hr types, a description of certain recently discovered blood factors and blood groups and their medicolegal applications, the use of blood tests as substantial evidence of paternity as well as for the exclusion of parentage, and also a model blood test law. Of these topics, the nomenclature is most important and difficult. The diversity of nomenclature