Janský demonstrated that blood could be classified into four groups; he named these O, A, B, and AB. His work, published in a little-known journal, was at first overlooked, and in 1910 Moss independently published work on exactly similar lines. A French résumé of the paper is in the above journal, pp. 131-33, and a German summary in Jb. Neurol. Psychiat., 1907, 1028.