2. There seems to be no good evidence of the production of addiction to these drugs. on the other hand, Dr. Golla points out that the subject rather rapidly becomes tolerant of, or adapted to their action, so that the power of inhibiting sleep becomes progressively weaker, with doses repeated on several successive days. Cases of idiosyncrasy may occur. L.C. Smith (J.Amer.med.Ass.,1939, 113, 1022) records a case of rapid death in a student who had, apparently, taken an ordinary dose to increase mental activity and prevent somnolence in an examination.