Extreme and long-continued fatigue is hostile to the development and

welfare of any nervous system, and especially to that of children
Extreme and long-continued fatigue is hostile to the development and
welfare of any nervous system, and especially to that of children. Not
only does overfatigue hinder growth, but it also results in the
formation of certain _toxins_, or poisons, in the organism, which are
particularly harmful to nervous tissue. It is these fatigue toxins that
account for many of the nervous and mental disorders which accompany
breakdowns from overwork. On the whole, the evil effects from mental
overstrain are more to be feared than from physical overstrain.