Manipulation for lumbar disc prolapse.

the National Drugs Advisory Board in Dublin in March, 1968. A full report is being prepared. While the association of bulk sales of these aerosols to occasional asthma deaths appears established, the exact nature of causation is not known. There is a need for more basic research on the effect of isoprenaline in man. It may well be that certain asthmatics develop an idiosyncrasy to it rather than a dosedependent effect on a hypoxic myoiardium in severe airways obstruction. This thought has occurred because of the beneficial use of intravenous isoprenaline in some low output states not always with a healthy myocardium or fully oxygenated arterial blood, and because of the apparently innocuous or moderate airways-obstruction present in many asthmatics shortly before an unexpected death.-I am, etc., W. D. LINEHAN. St. Mary's Hospital, Co. Dublin, Eire. REFERENCES Speizer, F., Doll, R., and Heaf, P., British Medical 7ournal, 1968, 1, 335. 2 Inman, W. H. W., and Adelstein, A. M., Lancet, 1969, 2, 279.