On one jar was written:

Germ culture which causes Red Death

On the other was inscribed:

Cure for Red Death

These the man in the serpent masquerade carried most carefully as he made his way in stealth toward the gilded pyramid.

Without being observed or arousing any slumbering Mayans, the snake man reached the pyramid. As he came near the monster pile of fabulously rich gold ore, he could not control his breathing, so strong was his lust for the yellow metal. The noisy purling of the stream of water down the pyramid side eliminated any chance of his being heard, though.

Up the steps the man felt his way in the intense darkness. The water raced by at his side. He reached the flattened top of the structure. There he felt about in the sepia murk until he found what he sought — a small, tanklike pool.

It was this pool that fed the racing brook down the pyramid side. Just how the pool was kept continuously supplied with water, in spite of its position high atop the pyramid, the man did not know or care.

He furtively lit a match.

The contents of the jar labeled Germ culture which carries Red Death, he emptied into the pool.

From experience, the fiend in the serpent mask knew the deadly germs would be fed down the pyramid water stream for about two days. And the entire clan of Mayans obtained their drinking water from that stream!

Two days and every person in the valley would be a victim of the gruesome Red Death. Only one thing could save them — treatment with the stuff in the other jar. Previously — for he had obtained many offerings of gold from this valley — the man in the snake mask had administered the cure exactly as he had the disease, by dumping it into the Mayan water supply.

It was because he saw the end of the golden offerings once Doc Savage appeared on the scene that the man had sought to keep Doc from reaching the Valley of the Vanished.

Carrying the empty jar, and the full jar of the cure, the man retreated down the pyramid. He made his way in silence to the remote end of the valley, where he had his hiding place. It was here he had concealed himself alter his plane pilot had dropped him by parachute into the valley the previous night.

En route, the man paused to smash the empty jar.

The clatter of the breaking glass instilled an ugly thought in his brain. He toyed with it.

"I will never learn the source of this gold from old Chaac," he growled. "And no one else knows the secret. So why should I trouble with curing them after they get sick?"

He made angry noises with his teeth. "If all in the valley were dead, I could take my time hunting the gold. And there is a fortune in that pyramid for the taking."

A mean grin crooked the lips back of the snake-head mask. "They will make many gold offerings before they find out I am not going to cure them!"

He had reached a decision that showed how evil and cruel he was. He had no regard at all for human life.

He crashed the bottle of Red Death cure against a rock, destroying it.

He intended to let the Mayans perish!

Chapter 17. THE BATTLE OF MERCY

Doc Savage, up ahead of the sun, spent the usual time at the exercises which kept his amazing bronze body the wonderful mental and physical thing it was. From force of habit he liked to go through his ritual while alone. Bystanders were always asking questions as to what this and that was intended to do, pestering him.

Morning Breeze was still a prisoner. Doc paid the cell hut a visit to be sure. The guards on duty eyed Doc's bronze form in open wonder, marveling at its perfection. Doc had not as yet donned his shirt.

Doc's bared arms looked like those of an Atlas. The muscles, in repose, were not knotty. They were more like bundled piano wires on which a thin bronze skin had been painted. And across his chest and back great, supple cables of tendon lay layer upon layer. It was a rare sight, that body of Doc's. The Mayans' eyes popped.

Some of the morning Doc spent in conversation with King Chaac, considering the elderly sovereign had never heard of a modern university, be had some remarkably accurate knowledge about the universe.

Pretty Princess Monja, Doc discovered also, would pass in any society as a well-educated young woman. All she lacked was a course in the history of the rest of the world. It was amazing.

"We lead a life of leisure here in the Valley of the Vanished," King Chaac explained. "We have much time to think, to reason things out."

A little later King Chaac made an unexpected — and pleasant — revelation.

"You may have wondered why I said I would delay thirty days or possibly less before I disclosed to you the location of the gold supply?" he asked.

Doc admitted he had.

"It was my agreement with your father," smiled King Chaac. "I was to satisfy myself you were a man of sufficient character to put this fabulous wealth to the use to which it should be put."

"That was not a bad idea," Doc agreed.

"I am satisfied," said King Chaac in a pleased tone. "To— morrow I show you the gold. But first, to-morrow morning you must be adopted into our Mayan clan. You and your men. That is necessary. For centuries the word has come down that none but a Mayan should ever remove the gold. Your adoption into the tribe will fulfill that command."

Doc expressed the proper appreciation. The conversation came around to how the gold was to be transported to civilization.

"We can hardly take it in the plane, due to the terrific air currents," Doc pointed out.

The elderly Mayan sovereign smiled. "We have donkeys here in the Valley of the Vanished. I will simply have a number of them loaded with gold and dispatched to your banker at Blanco Grande."

Doc was surprised at the simplicity of the scheme. "But the warlike natives in the surrounding mountains — they will never let a pack train through."

"In that you are mistaken," chuckled King Chaac. "The natives are of Mayan ancestry. They know we are here; they know why. And for centuries it has been their fighting which has kept this valley lost to white men. Oh, yes, they will let the pack train through. And no white man will ever know from whence it came. And they will let others through as the years pass."

"Is there that much gold?" Doc inquired.

But King Chaac only smiled secretively and gave no other answer.

The Red Death struck in the middle of that afternoon. A cluster of excited Mayans about a stone house drew Monk's curious attention. Monk looked inside.

A Mayan was sprawled on a stone bench. His yellow skin was mottled, feverish, and he was calling for water.

On his neck were vile red patches.

"The Red Death!" Monk muttered in a horror-filled voice. He ran for Doc, and found him politely listening to attractive Princess Monja. The young lady had finally cornered Doc alone.

Doc raced to the plane, got his instrument case.

Entering the Mayan's stone dwelling, Doc became at once the thing for which he was eminently fitted above all others — a great doctor and surgeon. From the highest credited medical universities and the greatest hospitals in America, from the best that Europe had to offer, Doc garnered his fabulous fund of knowledge of medicine and surgery. He had studied with the master surgeons in the costliest clinics in the world. And he had conducted unnumbered experiments of his own when he had advanced beyond the greatest master's ability to teach.

With his instruments, his supersensitive ear, his featherllght touch; Doc examined the Mayan.

"What ails him?" Monk wanted to know.

"It escapes me as yet," Doc was forced to admit. "Obviously it is the same thing that seized my father. That means it was administered to this man in some fashion by that devil who is behind all our troubles. Whoever he is, the fiend must be in the valley now. Probably the blue airplane brought him and dropped him by parachute at night."