"That hunter found you," he observed, "because he knew that you'd have to drink. So he found a brook and followed it up, looking for signs of humans drinking from it. He found footprints about the spring. I found his footprints there, too. That's the trick you'll use to find other fugitives. But pass on the word not to leave tracks hereafter. For other advice, I advise you to get all the weapons you can. Modern ones, of course. You've got the blaster from the man I killed."
"I think," said Kim between his teeth, "that I'll get some more. If hunters from the city do track us to our drinking places, I'll know how to get more weapons!"
"Yes," agreed Calhoun, and added, "Murgatroyd made the antibodies that cured you. As a general rule, you can expect antibody production in your own bodies once an infection begins to be licked. In case of extreme emergency, each of you can probably supply antibodies for a fair number of other plague-victims. You might try serum from blisters you produce on your skin. Quite often antibodies turn up there. I don't guarantee it, but sometimes it works."
He paused. Kim Walpole said harshly:
"But you! Isn't there anything we can do for you?"
"I was going to ask you something," said Calhoun. He produced the telephoto films of the city as photographed from space. "There's a laboratory in the city—a biochemistry lab. Show me where to look for it."
Walpole gave explicit directions, pointing out the spot on the photo. Calhoun nodded. Then Kim said fiercely:
"But tell us something we can do! We'll be strong, presently! We'll have weapons! We'll track down-stream to where hunters leave their ground-cars and be equipped with them! We can help you!"
Calhoun nodded approvingly.
"Right. If you see the smoke of a good-sized fire in the city, and if you've got a fair number of fairly strong men with you, and if you've got ground-cars, you might investigate. But be cagey about it! Very cagey!"