Show NEED FOR SLEEP the most important compensation foi all effects of fatigue by far the most important compensation for all effects of fatigue is sleep everybody even the man mentally most inert develops when awake a mass of mental effort which ho afford continuously without suffering we need therefore regularly recurring periods in which the consumption of mental force shall be slower than the con sinuous replacement the lower the da greo to which the activity of the brain sinks the more rapid and more the recovery the mental vigor of most men is usually maintained at a certain height for tho longest time in the forenoon evidence of fatigue come on later at this time of day than in the evening when the store of force in our brain has been already considerably drawn upon by the whole days work if no recovery by sleep is enjoyed or it is imperfect the consequences will invariably make themselves evident the day in a depression of mental vigor as well as in a rise in tho personal susceptibility to fatig the rapidity with which oha of the persons I 1 experimented upon could perform his task in addition sank about a third after a nights journey by railway with insufficient sleep another experimenter could detect the effects of keeping himself awake at night in a gradual decrease of vigor larking through four days this observation was all the more surprising because the subject was not conscious of the long duration of the disturbance and was first made aware of it incidentally by the results of continued measurements on the causes of the manifestations of fatigue popular science monthly |