“…The position is certainly less clearly defined than has been stated (Bates et al, 1971), both for myxoedema and thyrotoxicosis. The present results in thyrotoxicosis support the view of Lemon and Moersch (1924): "As to the primary fundamental physicochemical cause of the decreased vital capacity in hyperthyroidism, we are still uncertain and must await further investigation. However, we believe the secondary and direct cause is the cardiac inefficiency which arises from the primary source, the thyroid."…”