"What's the matter, Mark?" questioned Si, who was working with him at the time. "I--I don't feel right--my--my head is swimming around," gasped Mark. He had been affected by the strong sunshine, and Si called for help without delay. Bob came running up, and he and the former farm lad carried their sick chum away from the hole and up to the tent on the hillside. Then Maybe Dixon appeared. "Soak his head in the coldest water you can find," said the old miner, and Bob ran off with a pail to a spring coming from some rocks behind the camp. When the water was brought they saturated towel after towel and put it on Mark's head. They also fanned him and opened the tent front and back, that the breeze might blow through. "I am afraid he will be a sick boy for some time," said Maybe Dixon. "Maybe it will take all summer for him to git over it." "Oh, don't say that!" cried Bob, deeply distressed. The idea of any of the party having a serious spell of sickness had never before occurred to him. "Can't we get a doctor somewhere?" "I heard there was a doctor over to the settlement," said Si. "Jerry Bangs got some pills from him." "Then let us go and get him," answered Bob. "We've got plenty of money to pay him with." Bob determined to go over to the settlement the very next day, leaving Si to look after Mark and Maybe Dixon to work at the claims and watch them, so that nobody might "jump" their belongings. The week before a valuable claim had been "jumped" by two strangers, and the matter was still in dispute and at times threatened to lead to bloodshed. Bob went on muleback, taking the trail Mark had followed. He rode along as fast as he could and arrived at the settlement about the middle of the afternoon. "Can you tell me where the doctor's office is?" he asked, of the first man he met. "Sure I can," was the answer. "See that shack yonder?" "Yes." "Well, the doctor lives in the row of houses back of it--the third mansion--name on the doorplate--an' don't stop to ring the bell." "Thank you." Bob rode on and soon came to the row of houses mentioned, miserable two-story affairs, built of the roughest kind of boards. In front of one hung a shingle painted white on which was the following, in red: DOCTOR SAMUEL BARROWS Office Hours 8 to 11 A.M. 2 to 8 P.M. The place did not look particularly inviting, but Bob did not hesitate. He tied the mule to a post, walked to the dwelling, and knocked on the door. "What's wanted?" asked a negro who appeared. "I want to see the doctor." "Front room upstairs," and the negro disappeared in the direction of the rear. Bob entered the narrow and dirty hallway and ascended the rickety stairs. There were two rooms in the front, on the door of one of which was the sign: Doctor's Office--Walk In. Bob entered, closing the door after him. A voice from another apartment called out to him: "Who is there?" "I came to see the doctor."