4 68 SCIENCE PROGRESS 



her hand on her teacher's throat, mouth, and face, and read the 

 vibrations and movements of the mouth and expressions of the 

 face ; the same movements she learned to reproduce and thus 

 learned articulate speech. The sense of movement combined 

 with touch and smell were in her case the sole avenues of 

 stimulus to the brain from the external world, but inasmuch as 

 all the primary sensory areas including hearing and vision are 

 connected with these areas by association channels, the whole 

 brain responded to the stimulus and developed to the full its 

 innate educable possibilities. 



Sleep and Mental Development 



We now come to the last factor requisite for proper develop- 

 ment of the brain and especially its efficient function — sleep — 

 that sweet unconscious quiet of the mind which permits all the 

 vital bodily functions to continue (although less actively) while 

 the cortex of the brain rests and the whole organ stores energy 

 and recuperates. Sleeplessness is a sign of nervous irritability 

 and is cause as well as effect of mental fatigue and nervous 

 exhaustion. Darkness, stillness of the body, and silence favour 

 sleep by removing the principal causes of wakefulness and 

 activity of the mind. Habit fortunately permits of sleep under 

 the most unfavourable conditions ; still, the sleep of young 

 children must necessarily be a broken one in the single-room 

 tenement dwellings of the poor of our large cities. This is an 

 important unhygienic condition relating to mental development; 

 for insufficiency of rest to the brain tends to failure of mental 

 energy. The growing infant requires plenty of sleep ; so also 

 does the growing child, and especially is it so when the child is 

 suffering from bodily ill-health or nervous irritability. When 

 I was in Chicago recently I observed that all the children in the 

 Special School for Tuberculosis were made to lie in bed for an 

 hour in the afternoon. 



The question of nutrition in relation to mental development, 

 ability, and efficiency is one that until quite recently was not 

 properly considered by the authorities ; for until the mother's 

 health and her mode of feeding her offspring became a part of 

 social reform, the most important step in relation to nutrition 

 and mental development was left out. Statistics of Willesden 

 and Chester (which I throw on the screen) show that not many 

 children in these localities were suffering from imperfect nutri- 



