Most recent contributors to the literature on so-called "thymic death" are at a loss to explain this phenomenon. Painstaking research during recent years has led to only a few positive observations. The work of the English Status Lymphaticus Investigation Committee1on over 600 autopsies tends to question the existence of a thymic diathesis. The diagnosis of thymic death is frequently made the dumping ground of unexplained sudden death (Kennedy and New2). Enlargement of the thymus is often diagnosed erroneously on insufficient roentgenographic evidence (Hasley and Di Tomasi3). Boyd4observed that a large thymus is rather the rule than the exception in patients dying suddenly. The formerly prevalent conception that pressure on the thymus is responsible for so-called "thymic" asthma, and even for death, has lost considerable ground within recent years. In spite of these various observations tending to deny the original conception of Paltauf that a