Until they could not see, the dogs prowled and slaughtered. At night they came in bloody, most of it not their own, and exhausted. Marin pumped them full of antibiotics, bandaged their wounds, fed them through their veins, and shot them into sleep. In the morning he awakened them with an injection of stimulant and sent them tingling into battle. It took the rats two days to learn they could not feed during the day. Not so numerous, they came at night. They climbed on the vines and nibbled the fruit. They gnawed growing grain and ravaged vegetables. The next day the colonists set up lights. The dogs were with them, discouraging the few rats who were still foolish enough to forage while the sun was overhead. An hour before dusk, Marin called the dogs in and gave them an enforced rest. He brought them out of it after dark and took them to the fields, staggering. The scent of rats revived them; they were as eager as ever, if not quite so fast. The rats came from the surrounding meadows, not singly, or in twos and threes, as they had before; this time they came together. Squealing and rustling the grass, they moved toward the fields. It was dark, and though he could not see them, Marin could hear them. He ordered the great lights turned on in the area of the fields. The rats stopped under the glare, milling around uneasily. The dogs quivered and whined. Marin held them back. The rats resumed their march, and Marin released the dogs. The dogs charged in to attack, but didn't dare brave the main mass. They picked off the stragglers and forced the rats into a tighter formation. After that the rats were virtually unassailable. The colonists could have burned the bunched-up rats with the right equipment, but they didn't have it and couldn't get it for years. Even if they'd had it, the use of such equipment would endanger the crops, which they had to save if they could. It was up to the dogs. The rat formation came to the edge of the fields, and broke. They could face a common enemy and remain united, but in the presence of food, they forgot that unity and scattered--hunger was the great divisor. The dogs leaped joyously in pursuit. They hunted down the starved rodents, one by one, and killed them as they ate. When daylight came, the rat menace had ended. The next week the colonists harvested and processed the food for storage and immediately planted another crop. [Illustration] Marin sat in the lab and tried to analyze the situation. The colony was moving from crisis to crisis, all of them involving food. In itself, each critical situation was minor, but lumped together they could add up to failure. No matter how he looked at it, they just didn't have the equipment they needed to colonize Glade.