PHYSIOLOGICAL RHYTHMS. 



3 OI 



sure, high temperature, and tobacco ; it was increased 

 by practice, rest especially sleep food, increasing 

 atmospheric pressure, and alcohol. In this we have an 

 instance of the variations in the effectiveness with which 

 voluntary impulses act on the centres in the spinal cord. 



120 



80 



40 



FlG. 71. Showing at each hour of the day and night how many centimeters a 

 weight of 3,000 grammes could be raised by repeated voluntary contractions 

 of the forefinger before fatigue set in. The curve is highest at 10 to 1 1 a.m., 

 and 10 to 1 1 p.m. Lowest, 3 to 4 p.m., and 3 to 4 a.m. Circle with dot, obser- 

 vation made just after taking food ; square with dot, smoking ; * work done 

 eight minutes after drinking fifteen cubic centimeters of whiskey. (Lombard.) 



Recently Ostanikow and Gran 1 have published some 

 interesting figures concerning the diurnal variations of 

 reaction times. When a stimulus is given, and in 



1 Ostanikow and Gran, NeuroJog. CentralbL, 1893. 



