"You will recall," he continued slowly, "that way back in the twentieth century when the Martians first came to Earth, they were not made exactly welcome. Our first space ships were fired upon and many of our people were killed. Our next step was secret infiltration. We landed our ships in deserts and other isolated spots and unloaded select groups to intermingle with the Earth people and, because we are a superior race, soon many of our representatives held important posts among the governments of the Earth, especially that of the United States. To these Martians fell the task of breaking down ancient prejudices so that Earth could be opened to unrestricted trade and immigration. This was not easy. The men of Earth still remained hostile to us and, when we were unmasked as Martians, many of us were imprisoned and some were beaten to death, even executed. The people of Earth were, as a whole, complacent but they were whipped up to a frenzy by scare-mongers and demagogues whose voices it became necessary to silence. "Open retaliation would have done more harm than good and it was then that the Martians found the perfect weapon--Malutrex. This is a metal quite harmless to Martians for, as you know, our blood has a quite different composition than yours. We can handle Malutrex without the slightest danger. Look--" He reached down, coiled the slender chain about his wrist, caught the hook in the tongue-like catch of the delicate clasp then unloosened it again. He smiled and was silent for a minute, studying my face. When he spoke again it was with slow deliberation. "Maybe, you remember hearing tales long ago of 'the silent death'. Certain isolationist Congressmen and Senators who spear-headed the opposition to interplanetary development died mysteriously and without visible cause. Malutrex was the cause of their deaths." I was culling out half-forgotten bits of information that I had learned as a schoolboy. "But how--" Again the purple-flecked palm raised to interrupt me. "Earth men are hot-blooded. The chemical analysis of their bodies--but I won't bother you with the technicalities. In plain language, once a chain of Malutrex circles human flesh, it begins to shrink, slowly, almost invisibly. It grows tighter and tighter until it becomes a strangler's noose. And there is nothing, absolutely nothing, that the Earth man can do about it. Once the clasp is fastened, no matter how he tries, he cannot undo it nor, after a few minutes, can he loosen the chain from his skin. In most cases the victim is taken completely unaware by the death creeping upon him. Malutrex constricts gradually and painlessly except for the last spluttering moment of life." My knees felt a little weak and my stomach queezy. "Why tell me? Why should you let me in on this secret?"