And now Flora Hawkes saw all her well-laid plans upon the verge of destruction. She trembled as she watched the men before the fire, for her fear of Tarzan was very real, and then she became tense with nervous anticipation as she saw Kraski approaching the group with the coffee pot in one hand and cups in the other. Kraski set the pot and the cups upon the ground a little in the rear of Tarzan, and, as he filled the latter, she saw him pour a portion of the contents of the bottle she had given him into one of the cups. A cold sweat broke out upon her forehead as Kraski lifted this cup and offered it to the ape-man. Would he take it? Would he suspect? If he did suspect what horrible punishment would be meted to them all for their temerity? She saw Kraski hand another cup to Peebles, Throck, and Bluber, then return to the circle with the last one for himself. As the Russian raised it before his face and bowed politely to the ape-man, she saw the five men drink. The reaction which ensued left her weak and spent. Turning, she collapsed upon her cot, and lay there trembling, her face buried in her arm. And, outside, Tarzan of the Apes drained his cup to the last drop. CHAPTER VI DEATH STEALS BEHIND DURING the afternoon of the day that Tarzan discovered the camp of the conspirators, a watcher upon the crumbling outer wall of the ruined city of Opar descried a party of men moving downward into the valley from the summit of the encircling cliff. Tarzan, Jane Clayton, and their black Waziri were the only strangers that the denizens of Opar had ever seen within their valley during the lifetime of the oldest among them, and only in half-forgotten legends of a by-gone past was there any suggestion that strangers other than these had ever visited Opar. Yet from time immemorial a guard had always remained upon the summit of the outer wall. Now a single knurled and crippled man-like creature was all that recalled the numerous, lithe warriors of lost Atlantis. For down through the long ages the race had deteriorated and finally, through occasional mating with the great apes, the men had become the beast-like things of modern Opar. Strange and inexplicable had been the providence of nature that had confined this deterioration almost solely to the males, leaving the females straight, well-formed, often of comely and even beautiful features, a condition that might be largely attributable to the fact that female infants possessing ape-like characteristics were immediately destroyed, while, on the other hand, boy babies who possessed purely human attributes were also done away with.