Effect of Adrenalin Infusion on the Plasma Concentrations of Antihaemophilic Globulin in Normal Subjects and Haemophiliacs G. I. C. INGRAM (St. Thomas's Hospital, London) said that experiences in two haemophiliacs suggested that acute, severe bleeding was associated with a sudden rise in plasma antihaemophilic globulin (A.H.G.) activity. This seemed analogous to a previous observation that the clotting time in siliconecoated tubes shortened markedly after adrenalin infusions in normal subjects; and the effect of adrenalin on plasma A.H.G. activity was therefore investigated. Adrenalin (10-15 dAg./min.), isoprenalin, (3-5 Ltg./min.), and noradrenalin (10-15 Mg./min.) were infused for 10 min. in six normal subjects; so far, on the average, A.H.G. activity had risen after each drug, but most with adrenalin, with considerable individual variation. In two haemophiliacs, a marked rise was noted in one patient after two adrenalin infusions, but a fall in the other patient; in two severe haemophiliacs, there was no rise. Other experiments suggested that the effect is not an artifact related to contact factors or to fibrinolytic activity, and does not appear to be related to a fall in the eosinophil count a suggestive correlation has been observed between the A.H.G. rise and the rise in blood glucose concentration.