"Sharpie, you've got a one-track mind."

"It's the main track. Reproduction is the main track; the methods and mores of sexual copulation are the central feature of all higher developments of life."

"You're ignoring money and television."

"Piffle! All human activities including scientific research are either mating dances and care of the young, or the dismal sublimations of born losers in the only game in town. Don't try to kid Sharpie. Took me forty-two years to grab a real man and get myself knocked up-but I made it! Everything I've done up to the last two weeks has been 'vamp till ready.' How about you, you shameless stud? Am I not right? Careful how you answer; I'll tell Deety."

"I'll take the Fifth."

"Make mine a quart. Zebbie, I hate these monsters; they interfere with my plans-a rose-covered cottage, a baby in the crib, a pot roast in the oven, me in a gingham dress, and my man coming down the lane after a hard day flunking freshmen-me with his slippers and his pipe and a dry martini waiting for him. Heaven! All else is vanity and vexation. Four fully developed mammary glands but lacking the redundant fat characteristic of the human female-'cept me, damn it. A double stomach, a single intestine. A two-compartment heart that seems to pump by peristalsis rather than by beating. Cordate. I haven't examined the brain; I don't have a proper saw-but it must be as well developed as ours. Definitely humanoid, outrageously nonhuman. Don't knock over those bottles; they are specimens of body fluids."

"What are these things?"

"Splints to conceal the unhuman articulation. Plastic surgery on the face, too, I'm pretty sure, and cheaters to reshape the skull. The hair is fake; these Boojums don't have hair. Somethinglike tattooing-or maybe masking I haven't been able to peel off-to make the face and other exposed skin look human instead of blue-green. Zeb, seven-to-two a large number of missing persons have been used as guinea pigs before they worked out methods for this masquerade. Swoop! A flying saucer dips down and two more guinea pigs wind up in their laboratories."

"There hasn't been a flying saucer scare in years."

"Poetic license, dear. If they have space-time twisters, they can pop up

anywhere, steal what they want-or replace a real human with a convincing fake-and be gone like switching off a light."

"This one couldn't get by very long. Rangers have to take physical examinations."

"This one may be a rush job, prepared just for us. A permanent substitution might fool anything but an x-ray-and might fool even x-ray if the doctor giving the examination was one of Them... a theory you might think about. Zebbie, I must get to work. There is so much to learn and so little time. I can't learn a fraction of what this carcass could tell a real comparative biologist."

"Can I help?" (I was not anxious to.)

"Well-"

"I haven't much to do until Jake and Deety finish assembling the last of what they are going to take. So what can I do to help?"

"I could work twice as fast if you would take pictures. I have to stop to wipe my hands before I touch the camera."

"I'm your boy, Sharpie. Just say what angle, distance, and when."

Hilda looked relieved. "Zebbie, have I told you that I love you despite your gorilla appearance and idiot grin? Underneath you have the soul of a cherub. I want a bath so badly I can taste it-could be the last hot bath in a long time. And the bidet-the acme of civilized decadence. I've been afraid I would still be carving strange meat when Jacob said it was time to leave."

"Carve away, dear; you'll get your bath." I picked up the camera, the one Jake used for record-keeping: a Polaroid Stereo-Instamatic-self-focusing, automatic irising, automatic processing, the perfect camera for engineer or scientist who needs a running record.

I took endless pictures while Hilda sweated away. "Sharpie, doesn't it worry you to work with bare hands? You might catch the Never-Get-Overs."

"Zebbie, if these critters could be killed by our bugs, they would have arrived here with no immunities and died quickly. They didn't. Therefore it seems likely that we can't by hurt by their bugs. Radically different biochemistries."

It sounded logical-but I could not forget Kettering's Law: "Logic is an organized way of going wrong with confidence."

Deety appeared, set down a loaded hamper. "That's the last." She had her hair up in a bath knot and was dressed solely in rubber gloves. "Hi, dearest. Aunt Hilda, I'm ready to help."

"Not much you can do, Deety hon-unless you want to relieve Zebbie."

Deety was staring at the corpse and did not look happy-her nipples were down flat. "Go take a bath!" I told her. "Scram."

"Do I stink that badly?"

"You stink swell, honey girl. But Sharpie pointed out that this may be our last chance at soap and hot water in quite a while. I've promised her that we won't leave for Canopus and points east until she has her bath. So get yours out of the way, then you can help me stow while she gets sanitary."

"All right." Deety backed off and her nipples showed faintly-not rigid but

she was feeling better. My darling keeps her feelings out of her face, mostly- but those pretty pink spigots are barometers of her morale.

"Just a sec, Deety," Hilda added. "This afternoon you said, 'He didn't react!' What did you mean?"

"What I said. Strip in front of a man and he reacts, one way or another. Even if he tries to ignore it, his eyes give him away. But he didn't. Of course he's not a man-but I didn't know that when I tried to distract him."

I said, "But he did notice you, Deety-and that gave me my chance."

"But only the way a dog, or a horse, or any animal, will notice any movement. He noticed but ignored it. No reaction."

"Zebbie, does that remind you of anything?"

"Should it?"

"The first day we were here you told us a story about a 'zaftig co-ed."

"I did?"

"She was flunking math."

"Oh! 'Brainy."

"Yes, Professor N. O'Heret Brain. See any parallel?"

"But 'No Brain' has been on campus for years. Furthermore he turns red in the face. Not a tattoo job."

"I said this one might be a rush job. Would anyone be in a better position to discredit a mathematical theory than the head of the department of mathematics at a very prominent university? Especially if he was familiar with that theory and knew that it was correct?"

"Hey, wait a minute!" put in Deety. "Are you talking about that professor who argued with Pop? The one with the phony invitation? I thought he was just a stooge? Pop says he's a fool."

"He behaves like a pompous old fool," agreed Hilda. "I can't stand him. I plan to do an autopsy on him."

"But he's not dead."

"That can be corrected!" Sharpie said sharply.