250 



BIOLOGICAL PROBLEMS 



off and did little or no work, and so did not expose 

 themselves to the risk of accidents. Taking an aver- 



110 



ioo- 



Ejccesr Power Load 



r=y/^ 



70^.8 9 10 11 





L._ 



3 4 jr 07 8 



of "Day 



Fig. i. Hourly Variations of Accidents and of Output 



age of all the accidents put together, the women 

 suffered nearly three times as frequently in the fatigue 

 period as they did in the subsequent fourteen months, 

 when they were working ten hours a day instead of 



