organisms used the element. No one yet had found a planet with a halogen atmosphere, and, although there might be weird forms of life at the bottom of the soupy atmospheres of the methane-ammonia giants, no brave soul had ever gone down to see—at least, not on purpose, and no information had ever come back.

But such esoteric combinations are not at all necessary for the postulation of wildly variant life forms. Earth itself was prolific in its variations; Earthlike planets were equally inventive. Carbon, hydrogen, and oxygen, plus varying proportions of phosphorus, potassium, iodine, nitrogen, sulfur, calcium, iron, magnesium, manganese, and strontium, plus a smattering of trace elements, seem to be able to cook up all kinds of life under the strangest imaginable conditions.

Alphegar IV was no different than any other Earth-type planet in that respect. It had a plant-dominated ecology; the land areas were covered with gigantic trees that could best be described as crosses between a California sequoia and a cycad, although such a description would have made a botanist sneer and throw up his hands. There were enough smaller animals to keep the oxygen-carbon-dioxide cycle nicely balanced, but the animals had not evolved anything larger than a rat, for some reason. Of course, the sea had evolved some pretty huge monsters, but the camp of the expedition was located a long way from the sea, so there was no worry from that quarter.

At the time, however, the members of the expedition didn’t know any of that information for sure. The probe teams had made spot checks and taken random samples, but it was up to the First Analytical Expedition to make sure of everything.

And this much they had discovered: The plants of Alphegar IV had a nasty habit of killing test animals.

“Of course,” said Dr. Pilar, “we haven’t tested every plant yet. We may come across something.”

“What is it that kills the animals?” asked young Captain Bellwether.

“Poison,” said Major Grodski.

Pilar ignored him. “Different things. Most of them we haven’t been able to check thoroughly. We found some vines that were heavily laced with cyanide, and there were recognizable alkaloids in several of the shrubs, but most of them are not that direct. Like Earth plants, they vary from family to family; the deadly nightshade is related to both the tobacco plant and the tomato.”

He paused a moment, scratching thoughtfully at his beard.

“Tell you what; let’s go over to the lab, and I’ll show you what we’ve found so far.”

Colonel Fennister nodded. He was a military man, and he wasn’t too sure that the scientists’ explanations would be very clear, but if there was information to be had, he might as well make the most of it.

SM/2 Broderick MacNeil kept a firm grip on his blast rifle and looked around at the surrounding jungle, meanwhile thanking whatever gods there were that he hadn’t been put on the fence-mending detail. Not that he objected violently to work, but he preferred to be out here in the forest just now. Breakfast hadn’t been exactly filling, and he was hungry.

Besides, this was his pet detail, and he liked it. He had been going out with the technicians ever since the base had been finished, a couple of weeks before, and he was used to the work. The biotechnicians came out to gather specimens, and it was his job, along with four others, to guard them—make sure that no wild animal got them while they were going about their duties. It was a simple job, and one well suited to MacNeil’s capacities.

He kept an eye on the technicians. They were working on a bush of some kind that had little thorny-looking nuts on it, clipping bits off here and there. He wasn’t at all sure what they did with all those little pieces and bits, but that was none of his business, anyway.