In an attempt to gain insight into the activity of the adrenal gland in relation to salt and water metabolism in mental disease, Grunebaum and Altschule studied the sodium concentration of sweat in patients during treatment. The usual increased sweat sodium concentrations were found to fall to normal during insulin therapy, electric shock therapy, and spontaneous remission. These observations suggest that the treatment must stimulate production of those hormones which control the electrolyte balance, and suggest that abnormal function of the adrenal cortex may occur in mental disease. On the other hand, there was also evidence to indicate that some psychotic patients whose sweat sodium returned to normal did not manifest any clinical improvement.