This communication is based on a study of twenty cases of skull injury, four previously reported and sixteen comprising the present series. Foerster,1Wartenberg2and especially Schwab3were the first to demonstrate abnormal encephalographic conditions in patients who had sustained skull injuries. Later, Heidrich,4Bielschowsky,5Pancoast and Fay,6Foerster and Penfield,7Frazier and others reported similar observations. In a paper on encephalography I included four cases of the posttraumatic state with abnormalities in the encephalogram.8Since then I have had the opportunity of observing sixteen additional cases of skull injury, the encephalographic conditions in which are reported in this communication. REPORT OF CASES Case 1. History. —Charles E. H., aged 39, a construction worker, was admitted to Bellevue Hospital on Nov. 21, 1929, complaining of pain in the back, headache and attacks of unconsciousness for one year. The previous and family histories