*Nervous Overstrain.*—Both mental and physical overwork tends to weaken the nervous system and to produce nervousness. Where hard mental work is long continued, or where it is carried on under excitement, a tense nervous condition is developed which is decidedly weakening in its effects. The causes which lead to such a condition, and in fact overwork of all kinds, should if possible be avoided. Where this is not possible, and in many cases it is not, the period of overwork should be followed by one of rest, recreation, and plenty of sleep. To the overworked in body or in mind, nothing is more important from a hygienic, as well as moral, standpoint, than the right use of the _one rest day in seven_. The best interests of our modern civilization _require_ that the Sabbath be kept as a quiet, rest-giving day. *Disturbed Circulation of the Brain.*—Nervousness not infrequently is accompanied by an increase in the circulation of the brain and disappears when this condition is relieved. Though mental work and excitement tend naturally to increase the circulation in the brain, this should subside with rest and relief from excitement. When there is a tendency for this condition to become permanent, effort should be made looking for relief. Increasing the circulation in the lower extremities by hot or cold foot baths, or by much walking, is found to be most beneficial. Special exercises of the muscles of the neck are also recommended as a means of relieving this condition.(110) *Hygienic Value of Work.*—Within reasonable limits, both mental and physical work are conducive to the vigor of the nervous system. Through work the energies of the body find their natural outlet, and this prevents dissipation and the formation of bad habits. Even hard work does not injure the nervous system, and severe mental exertion may be undergone, provided the proper hygienic conditions are observed. The nervous disorders suffered by brain workers are not, as a rule, due to the work which the brain does, but to violation of the laws of health, especially the law of exercise. Such persons should observe the general laws of hygiene and especially should they practice daily those forms of physical exercise that tend to counteract the effects of mental work.