Old Billee riding in from off the distant range one day, called to Bud who was opening some of the reservoir gates to let water run to a distant trough for the cattle. "Bad business, Bud!" exclaimed the veteran. "What's that?" asked the lad, with an instinctive glance at the black pipe, whence the water spouted. His first thought was of that. "There's five of your steers dead, over near the last water trough!" was the answer. "Steers dead!" gasped Bud. "Rustlers?" he asked, quickly. "Don't 'pear to be," Billee answered. "There isn't a mark on 'em. Maybe it's glanders. Better get Doc. Tunison right over." Which Bud did, by telephone. The veterinarian, who looked after the health of cattle in that vicinity, appeared in due season. Bud, with his cousins and Old Billee went out to where the dead cattle lay, now stiff and stark. Some buzzards flopped heavily off as the party approached. "Hum!" mused Dr. Tunison as he began his examination. It did not take him long to complete it. "I thought so," he remarked, as he looked at Bud. "What is it?" "Germs!" was the answer. "The epidemic's struck you, Bud!" CHAPTER XVIII ROPED! Like a blow struck came that announcement to Bud Merkel. And to his chums and partners in their first small venture as boy ranchers on their own responsibility, the announcement of the veterinarian was staggering. "Germs!" exclaimed Nort. "Epidemic!" voiced Dick. "Has it really struck here--the same disease that was among dad's cattle?" asked Bud, as though hoping there might be some mistake. "It's here all right," went on Dr. Tunison, rising from his stooping position beside a dead steer. He looked about for a puddle of water in which to wash his hands, and, having completed the operation, using a disinfectant from a bottle he produced, he added: "Better fence off this puddle, Bud. If any of your other cattle happen to drink here they'll get the disease, too, and bump off." That was his way of saying that the steers would die. "I'll do that!" declared Bud. "We can cut the water off from this part of the range. But what causes the epidemic, Doc? Dad was careful not to send me any of his infected cattle from Square M, and he said you'd examined all that came, and they didn't have any of the trouble." "They didn't," declared the veterinarian. "I examined them all, and nothing was wrong with them. But this epidemic is a germ disease, Bud, and we don't exactly know how the germs are carried. It may be something the cattle eat; the bunch grass or other fodder, in the water; or it may come out of the air. All we know is that certain germs, in some, as yet unknown, way, enter into the system of the steer. They get into the blood through the mouth or nostril, or perhaps from a scratch or cut. And once the germs are there, so rapid is the action that the animals die over night--as yours have done, and as your father's did." "Has dad lost any more?" asked Bud.