The Intimate Causes of Old Age. 235 



each individual cell attends to its own personal affairs, 

 namely, nutrition, expulsion of waste products, self- 

 adjustment, and rest. Sleep is the time when the brain 

 cell is again living the original unicellular life of its 

 remote ancestry, resting, restoring its powers. 



So exhausting is the daily, corporate life, the main- 

 tenance of the intellect, that this succeeding period of 

 unicellular life is necessary to the neuron's restoration. 

 It must have time to attend to its unicellular wants and 

 necessities before again devoting itself to the united brain 

 life of another day. 



It is not difficult, therefore, to understand what takes 

 place when from any cause, the cell is prevented from 

 properly attending to this its necessary individual life, 

 that is, when it does not wholly break continuity with the 

 other cells ; when its waste products, accumulating during 

 the day, are not cast forth ; and when it is not permitted 

 to pass into a state of cell rest. Disturbed, broken sleep 

 leads to constant interruptions of these necessary pro- 

 cesses of unicellular life. The brain is now like an army 

 of soldiers, harassed by constant night attacks, to the ex- 

 tent that the individual soldier is kept in line, day and 

 night, with no time to eat, sleep, or attend to his personal 

 wants. 



The brain cells, although still unrested, and but half 

 purged of their waste products, are compelled to resume 

 unification in self-consciousness, when a person wakes. 



