ABO Groups in Blood Platelets.
—At the March meeting of the Israel Microbiological Society, J. Gurevitch and D. Nelken of Jerusalem reported that suspensions of blood platelets in normal sodium chloride solution are agglutinated by A, B, and O serums, just as these serums agglutinate red blood cells of the corresponding blood group. It is thus possible to establish four blood groups for the blood platelets, similar to those of the erythrocytes. To 0.3 to 0.5 cc. of inactivated serum in a tube an equal volume of the platelet suspension was added and left at room temperature for two hours. The result of agglutination was read microscopically after two hours by withdrawing several drops of the serum-platelet suspension and spreading it on a slide. Agglutinates of different sizes, from several to tens of thrombocytes, and large clumps of platelets were clearly visible at low magnification. At the first reading after