Sometimes it happens that a headache recurs periodically or at regular intervals. It is easy to see that in such cases the exciting cause is fear and expectation. At some time in the past, headaches have occurred at an interval of, say, fourteen days; as the next fourteenth day approaches the sufferer says to himself: "It is about time for another headache. I am afraid it will come to-morrow," and of course it comes. One man told me that if he ate Sunday-night supper he inevitably had a headache on Monday morning. We were about to sit down to a simple Sunday supper and he refused very positively to join us. I told him he could stay all night and that I would take care of him if the Monday sickness appeared. He accepted my challenge but was unable to produce a headache. In fact, he felt so unusually flourishing the next morning that he insisted on frying the bacon for my entire family. That was the end of the Monday headaches. =A Few Examples.= As sick-headache has always been considered a rather stubborn difficulty, not amenable to most forms of treatment, it may be well to cite a few cases which were helped by educational methods. A patient came home from a walk one day and announced that he was going to bed. When questioned, be said: "I am tired and I have a sick-headache. Isn't it logical to go to bed?" To which I answered that it would be far more logical to put some food into his stomach and change the circulation than to lie in bed and think about his pain. This man was completely cured. I have had patients throw up one meal, and very rarely two, but I have never had to supply more than three meals at a time. The waste of food I consider amply justified by the benefit to the patient. There once came to me an elderly woman, the wife of a poor minister. She was suffering from attacks of nausea, which recurred every five to ten days with intense pain through the eyes, and with photo-phobia or fear of light. I found that she had by dint of heroic efforts raised a large and promising family on the salary of an itinerant minister--from four hundred to six hundred a year! All the time she had been feeling sorry for herself because her husband did not appreciate her. One day, after reading one of his letters which seemed to show an utter lack of appreciation of all that she was doing, she fell down in the field beside her plow, paralyzed. From that time on she had been more or less of an invalid, continually nursing her grudge and complaining that she ought not to have been made to bear so many children.