THE PHYSIOLOGY OF SLEEP. 



241 



J 5Jf 30 MS 6 b.l$ 



Fig. 107. Curve of intensity of sleep according to Monninghpff and Piesbergen. The 

 figures along the abscissa represent time in hours from the beginning of sleep ; those along 

 the prdinate the relative intensity of sleep measured in milligram-millimeters, expressing 

 the intensity of sound of a falling body necessary to awaken the sleeper. 



fig. 108. Curve of intensity of sleep in a child of three years and eight months, as deter- 

 mined by Czerny. 



16 



