The physiological problem is uncomplicated. As Dr. Learned, who more than a quarter of a century ago cured himself of habitual insomnia by getting control of the respiratory and circulatory functions in the sleeping posture, has made clear, the problem is simply to shift the belt of attention from the wildly whirling wheel of introspection to the steadier wheel the will revolves.

By deep regular respirations, accompanied by rhythmical movements of the head and hands and feet, Dr. Learned has frequently brought the wandering attention back from some side track it sought in fitfulness to the main line of the controlled consciousness. So surely has he in recent years become convinced that the problem is usually psychical that he no longer emphasises physical exercises in or out of bed. Instead he provides an ingenious little tablet on which the wakeful one with unlifted pencil steadily records in waving lines his inhalations and his exhalations until at last, fatigued by the long exercise, the brain becomes anÆmic and sleep overtakes the drowsy mind.