The Lieutenant hid his vehicle in a copse of trees close to the deserted side road. He slid off the seat, glad to escape the cramped position behind the wheel. As he walked toward the oil field, his wound began to pain him again. With his tongue he worked the small capsule loose from the back of his mouth--the only place where he could conceal it, since the computers had decreed that he come naked to this world. He stooped beside a sump and watched the black earth filter slowly through the membrane into the capsule. In his own mind Henig had no doubt that the petroleum resources here were economically worth exploitation. He thought, for a moment, of the brutal occupation by the empire fleet--the slaughter and the destruction, before the survivors could be herded into prison reservations. The killing and the burning of their primitive cities didn't disturb him. The aliens were animals. Because of their biological evolution, they would never achieve a higher social level. They were eternally tied to emotion, and a logical civilization was beyond their mentality. To wipe them out meant no more to Henig than the extermination of a germ colony or a nest of vermin. Still the particular emotion dominating these bipeds was unique. It was worth preserving--if that emotion actually existed; if he were reading the data correctly. The Lieutenant still didn't know; he still couldn't make up his mind. The test earth seeped slowly into the capsule. Henig raised his eyes and studied the field. It was dark and the skeletal shafts of the oil derricks were silhouetted against the glow of the city lights. The hairless bipeds had developed the field extensively. Two or three generations ago, Henig thought enviously, the planet must have been enormously rich in oil if, after so much native exploitation, it was still worth an empire invasion. Two galactic millennia had passed since the empire had reached that same period in technological growth, depleting the petroleum resources of a hundred worlds. The empire had to have oil. Not for fuel--atomic energy had been harnessed long ago--but for lubrication. All the scientists, all the logical computers which governed the empire, had never come up with a satisfactory substitute. The sample capsule was full. Henig stood up, sealing the vial again at the back of his mouth. And as he turned toward the road, he saw one of the aliens watching him. Behind the biped a pipe was burning gas exhausted from the field. The flame lit the animal face and Henig saw the crushing weight of terror. The animal turned and ran, blowing on a whistle which was suspended around its neck. Henig sprang after him and caught the white thing with a blow that split the fragile neck bone. But one blast on the alarm whistle had been enough. Henig saw other animals pouring out of the low-roofed, stone building nestled among the oil derricks. Bright lights blazed up, sweeping the field with a deadly glare.