"You know," began the other, seizing a moment when his throat was clear, "I said I'd seen the faces of the men of Sungan. They had their hands on me, and I saw them close. I did not tell you at first what I deduced from that." Gray nodded, thinking how the explorer had broken off in the middle of a sentence in his story of two hours ago. "Don't forget, Captain Gray----" a flash of eagerness passed over the tanned face--"I was the first in Sungan. I want the men who sent me to know that. Well, the faces I saw were white--in spots." Gray whistled softly, recalling the words of Brent. The missionary had said that the man he saw in the Gobi was partially white. Also, Mirai Khan had said the same. "Those men, Captain Gray, were not white men. They were afflicted with a disease. I've seen it too often--to be mistaken. It is leprosy." Mechanically, Gray fingered his pipe. Leprosy! This sickness, he knew, caused the flesh of the face to decay and turn white in the process. And leprosy was common in China. "I've been thinking," continued the Englishman, "while I was waiting to sight your caravan. There are lepers in the ruins of Sungan. That may be why the spot is isolated. The Chinese have leper colonies." "Yes," assented Gray. Neither man voiced the thought that was uppermost in his mind, that Mary had been seized by these men. "Mirai Khan told me that Sungan was an unclean place. The Kirghiz--who are fairly free from the disease--avoid Sungan. Delabar, my companion, feared it, I think." "This explains the myth of the white race in the Gobi--perhaps. And the guards." "Mirai Khan said that men were brought from China, from the coast, to the sands of Sungan," added Gray grimly. "God--why didn't they warn us?" "You were warned, Captain Gray. Our caravan traveled as secretly as possible. I--I paid no attention to what the Chinese said. They have their secrets. I should have been more cautious. I made the mistake of my race. Overconfidence in dealing with natives. I wanted to be the first white man in Sungan." He paused, reaching for a cup of water that Gray had filled for him. The American watched him blankly. So the talk of the pale sickness had proved to be more than legend. And he had discovered the root of Delabar's dread of the Gobi. Why had not the scientist said in so many words that Sungan was a leper colony? Doubtless Delabar had known that Gray would not turn back until he had seen the truth of the matter for himself.