Dr. G.L. Ada is distinguished for two fundamental contributions to the fields of chemical virology and biochemistry. Ada and Perry, in 1954, for the first time unambiguously demonstrated that the genetic material of influenza virus is a ribonucleoprotein. Since all systems of genetic interaction available at that time were of the DNA type, this discovery greatly widened the scope of potential genetic studies. This finding, remarkable on considering the technical difficulties involved, has since been repeatedly confirmed in other laboratories and still serves as a model for the investigation of animal viruses. The second major achievement was the crystallization of Vibrio cholerae neuraminidase. This enzyme, isodynamic with the enzyme of the myxoviruses, has played an important role in the study of virus-host cell interaction and in the elucidation of the fine structure of sialo-glycoproteins since 1946. The availability of this enzyme without contaminating proteases is of the greatest value. A considerable amount of research work emerging from these discoveries was carried out in Ada's laboratory.