The selection of patients with mitral stenosis for valvotomy is considerably influenced by the degree of dyspncea of which the patient complains, and in many cases the history of progressive dyspncea with episodes of acute pulmonary cedema or haemoptysis makes the need for operation obvious. In some cases, however, fatigue is confused with dyspncea as a reason for limiting physical activity or the synmptoms of the effort syndrome may be superimposed so that some objective measurement of the degree of disability might be of value. Attempts to correlate the degree of dyspncea with the circulatory changes in the heart and lungs, measured by means of the cardiac catheter, or with results of tests of respiratory efficiency have given conflicting results. Most of these studies have been carried out with the patient at rest but even when repeated during steady exercise the same lack of correlation has been reported (West et al., 1953).Pathologists have long been familiar with the fact that the lungs of patients dying in heart failure were more rigid than normal lungs, but it was not until 1934 that Christie and Meakins (1934) measured in vivo the distensibility of the lungs in patients with congestive heart failure by means of simultaneous tracings of the tidal air and the intrapleural pressure fluctuations. They showed that in heart failure the lungs were more rigid than normal, probably because of pulmonary congestion, and that with clinical improvement the distensibility of the lungs improved. There was thought to be a direct relationship between the degree of lung rigidity and the amount of dyspncea and it was later suggested that cardiac dyspncea was reflex in origin, the increased lung rigidity through the Hering-Breuer reflex causing the rapid shallow breathing of heart failure (Christie, 1938). Because of the necessity of inducing a small pneumothorax to record the changes in intrapleural pressure little use has been made of the method of Christie and Meakins (1934) of measuring the pulmonary distensibility in cardiac patients. Dornhorst and Leathart (1952) have shown that an accurate record of changes in intrathoracic pressure can be obtained by recording the pressure changes in the cesophagus and this method has been used to study on a larger scale changes in lung distensibility and respiratory work in heart failure (Marshall et al., 1954).If the degree of cardiac dyspncea is directly related to the increased rigidity of the lungs, the measurement of pulmonary distensibility might be of help in assessing the amount of disability. In this investigation the relationship between dyspncea and pulmonary distensibility and respiratory work has been studied in 30 patients with mitral stenosis. Measurements were made at rest, and during and immediately after exercise, and in 6 patients were repeated 3-6 months after mitral valvotomy. METHODSChanges in intrathoracic pressure were measured using an cesophageal catheter and these were recorded simultaneously with records of the tidal air obtained with the pneumotacho...

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SUMMARY The excretion of steroid hormone metabolites was studied in normal, thyrotoxic and myxoedematous subjects. Corticosteroid excretion was increased in thyrotoxicosis and reduced in myxoedema. In myxoedema there was also a fall of total androgen excretion due principally to a reduction of the androsterone component. There was no change in total androgen excretion in thyrotoxic subjects, but there was a fall of aetiocholanolone excretion.

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