The second Martian, not having seen Spartan, seemed to freeze in terror for an instant. Possibly there had been some sort of a dying scream from his companion--one that could not be heard on the wave length of our helmet receivers. At any rate, it took only a split second for Martian No. 2 to realize we were neither weak nor harmless, as we had seemed. He turned and fled toward the canal at full gallop. His speed was astonishing. Dr. Spartan fired again. His shot missed and sent a geyser of sand skyward, ahead of the fleet monster. He swore and fired again. But the next shot was not an explosive bullet. It missed, too, and he switched his weapon to automatic and emptied the magazine with rapid fire. I saw the path cut across the sand and intercept the Martian. The creature staggered, then sank to the ground. "Hah!" Spartan exclaimed triumphantly. "Let's take the dead creature to the ship! I'd like to see how he's constructed." It was a gruesome business, but we loaded the scaly body into the locks of our car. The one Spartan had shot first was too torn and shattered to be worth transporting. Besides, the fluid that might be called blood, or sap, looked like acid and I was afraid it might damage the floor of the locks. My judgment turned out to be correct, for when Gail, our biologist, examined the beast we brought back, she announced that he was a mass of deadly poison and so were the plant samples I'd brought back from the canals. "What kind of poison?" Spartan asked. "I'm not sure, but Bill Drake can tell with a few tests," she said. Spartan gestured to me. "Go ahead, Drake." I got chemicals from the supplies Axel brought from the overturned ship and set to work. It was fortunate that I made these tests. The Martian plants and the dead Martian were very similar chemically, giving rise to speculation that the evolution of life on Mars had taken place about the time the planet had stabilized into its present state. On earth, life began while the planet was evolving from an earlier form and the changes continued while life developed. The changes probably brought about the division of the animal and vegetable kingdoms and they might have continued until sixty million years ago when the giant reptiles were wiped out, or even later through the glacial ages. But on Mars there was only one kingdom. It wasn't wholly animal, or wholly vegetable, although it was more the latter than anything else. And the tissues were formed from a very deadly series of molecules which had cyanide as their base. In other words, Martians were poison to us, and very likely we were poison to the Martians. Furthermore, the water we had brought from the Martian canal was impregnated with ammonium hydroxide, in large enough quantities to cause serious illness should we be foolish enough to drink it. However, it was very useful for washing the cyanide from our gloves and spacesuits after we performed the autopsy.