4 i4 POPULAR SCIENCE MONTHLY. 



of the blood vessels and thus the vasomotor mechanisms are taxed 

 heavily. The head should be permitted to rest as nearly upon a level 

 as the feet, though most people prefer some support. The blood should 

 be encouraged to reach all parts of the body equally, hence the limbs 

 had best be extended, not flexed ; the habit of extending the arms above 

 the head is a particularly bad one. 



To secure the most perfect repose the temperature of all parts 

 should be equalized before retiring. Cold feet induce delay in securing 

 sleep and it is then shallow when attained. The bladder and bowels 

 by weight of their contents will interfere with repose, hence they 

 should be previously emptied. It is most unwise to overfill the stomach 

 before retiring; this disturbs sleep almost as much as hunger, but 

 moderate eating before sleeping is not hurtful, and is often salutary. 



Sleep is only a function; therefore, whatever disturbs it depends 

 on structural derangement of some sort. Disorders of sleep are mani- 

 fold. The commonest are psychic exaltations or depressions, worries, 

 brooding on the cares of the day, continuing to dwell on the waking 

 problems. Habit is ever forceful. A well-trained mind will promptly 

 shut off or readily let go of the thought processes. Unnatural activity 

 of the sensory and association centers causes dreams ; that of the motor 

 centers results in shocks, starts and spasmodic phenomena. Control of 

 the visceral centers may become inhibited, permitting unconscious dis- 

 charges from the bladder, intestines or sexual organs; innervation of 

 the lungs or heart being thus deranged, palpitation or dyspnoea is 

 induced. Sensory centers being over-stimulated, sensations of light 

 follow, or of sound, also pain or vertigo. " In fine, the ordinary 

 smooth current of the subconscious activities breaks against some pa- 

 thologic states and now one symptom, now another, is thrust out and so 

 unpleasantly that the sleeper awakens" (C. L. Dana). 



A review of Dana's remarks on the disorders of sleep will be useful 

 to achieve an understanding of the varieties and phenomena of in- 

 somnia; a better term perhaps would be difficulties of sleep. Some 

 people, especially those of middle age, fall asleep easily, but wake in 

 the small hours and thereafter only doze fitfully. This may be due to 

 beginning degenerative changes in the arteries, connected with the effects 

 of worries and strains, or only a habit, or echo of youthful customs of 

 early rising, or an acquired weakness or irritability of the heart. 

 Others fall asleep readily, but are soon disturbed by little explosions 

 of motor, sensory or psychic forces. The body or limbs start or jerk; 

 sleep follows, but these nervous explosions may be repeated two or three 

 times. It is usually the result of exhaustion, psychic or muscular 

 over-tension, physiologic irritability, indigestion, nervous fatigue, or 

 may foreshadow some serious derangement. Sudden awakenings often 

 betray emotional distress, fear or disorders of ideation. 



