846 



PERIODIC FUNCTIONS IN MAMMALS 



Blood 

 Sugor 

 (mg.7o) 



200 



50 



100 - 



Light 06:00 - 18:00 



t = 7.97 ; P<: 0.001 



Light I8:00 - 06:00 



[3 12:00 

 ■ 24:00 



t = 4.96; P<0.001 



Fig. 19. Shift in phase of blood sugar rhythm after inversion of light- 

 ing regimen in mouse. Horizontal lines and shaded areas around them 

 denote ±1 standard error. 



both schedules were then killed on the same day, at the same two 

 times which were those of the daily "high" and "low" in a given variable 

 (previously established on a regular schedule of lighting in experi- 

 ments based upon data from seven groups of mice, killed at 4-hr 

 intervals, during each of two independent 24-hr periods) (Barnum 



Lighting 

 regimen 



50 



18100 06:oo 06;oo i8;oo 



06:oo 



'.ISHT: 



!ilDARK!j: 



L.ISHT 



+ 1 S.E. 



-08:30 



-20:30 



n 



Fig. 20. Shift in phase of liver glycogen rhythm after inversion of 

 lighting regimen in mouse. 



