When I first began the study of mental disorders, I realized that patients were, apart from their mental disorder, physically ill, and I was attracted to a study of the circulatory disturbances in these cases. This led me to consider whether these general circulatory disturbances were responsible for the mental state, in the same way that intracranial circulatory disturbances were in surgical brain cases showing mental symptoms. Examination almost invariably revealed weakness of the heart's action, irregularity of the pulse, low or high blood-pressure, and disturbances of the peripheral circulation. It was thus conceivable that disturbance of blood composition and supply might cause disturbance of oxidation in the brain and that many of these abnormal circulatory manifestations might be responsible for the production of mental disturbances. A study of various physiological and biochemical observations suggested that possibly there was in these cases some deficiency of essential salts, such as calcium. This led me to the treatment of mental disorders by the administration of salts of calcium—choosing calcium lactate. Fortunately I found at that time (1919) a very remarkable case showing severe mental symptoms and unusual circulatory disturbances.