McCowan and Quastel (5) have shown, in recent work carried out in this hospital, that a close relationship exists between variations in the affective state of psychotic subjects and abnormalities in the glucose tolerance curves. So marked is the parallelism between these two that it has been found possible to make use of an index, known as the hyperglycæmic index (H.I.), which furnishes a valuable guide to the degree of emotional tension experienced by the subject. The method of determining the index is fully described in their paper; but it may be briefly stated that it is zero when the glucose tolerance curve is normal, and varies up to 100, depending upon the degree of sustained hyperglycæmia present. The affectivity of the patient was determined clinically, and, in order to test the validity of their thesis that the emotional tension and H.I. varied pari passu, it was considered that objective evidence of the patient's affectivity would be of value.