73 



281 



there may nevertheless exist a slight effect of fatigue, as the amount of work 

 decreases in the very beginning for later on to become constant; and corresponding 

 Aariations of metabolism are observed. 



If the work is so long or difficult as to produce a plainly expressed sensalion 

 of fatigue, the amount of work ina\ nevertheless remain constant, or even grow to- 

 wards the end ,vhile the metaboli ' increases grow relatively much stronger. 



An uncomfortable position during »vorl. i>i able to cause so great an increase 

 of metabolism, that the influence of the accomplished work on the metabolic in- 

 creases is wholly untraceable. 



The measurements of metabolism show that mental as well as bodily fatigue 

 are caused by the impossibility of replacing at once the energy transformed in the 

 working organ, and this explains the reduced amount of work as well as expenditure 

 of matter in the beginning, even where easier work is concerned and fatigue scar- 

 cely felt. 



A vigorous motive of keeping the amount of work constant when hard and 

 tedious work 1,^ done and the subject feels tired is likely to set fresh centres at work, 

 but the greatly increased metabolism shows that the efficiency of the activity of 

 these is very small. 



The fact thai fatigue appears during mental work shows plainly that a fairly 

 big part of the obtained increases of metabolism must issue from the work of the 

 central nerve system. 



I). K. I). Vlilcnsk. Selsk. Skr., niitiirvlclensk. o|ï mnthcni. Afd , 8. Række, 111. 2. 



36 



