Po and his visitors were in a fairly goodsized laboratory adjoining Po's office. Beakers on a counter contained dark red liquid that Hi and his friends assumed to be blood. The Dracaena, with the help of the small square table on which it sat, stood higher than Po did, and was not quite like anything in the plant line that Hi and the others recalled seeing. Po gently lifted for display one of the large red blooms. "The flower is much like a rose." He then drew their attention to the Dracaena palm's stem, about the size of a quarter in circumference. "By the first, oh, one hundred and twenty days, the young plant develops, right here in the stem, a red-colored liquid, called appropriately dragon's blood." Po chuckled. "If only they knew."

"Who?" Hi asked.

"The vampires."

"Knew what?"

Po answered with a sudden flare of temper: "The nature of the plant's red secretion, you fool!" Po then smiled again, as he moved to another table. "Which brings us to our friend here. The vampire bat."

The bat was hanging upside down, as bats are wont to do, from a perch secured to the table. The bat was tethered to the perch by one leg. Vampire bats, with their snouts, fangs, and small piercing eyes, were always ugly in pictures, and Po's visitors, looking at the real thing, could see why.

"The Desmodonidas," Po said. "Do not worry. He is tied, he cannot attack you. Now I asked myself, in researching: Is there a particular reason why the Greeks would name this plant for the vampire? Why, besides color, might this liquid be called dragon's blood? Well, the liquid was named, I was able to conclude, not for its bloodlike appearance, but for its effect upon blood. Dragon's blood. The 'blood of the devil.' When you called, about one half hour ago, I chose this bat to show you. I had fed it, with liquid extracted from the palm, about five and a half hours ago." Po glanced at his watch. "In another half hour, it will happen."

"What will?" Hi asked.

"The destruction of the vampire. How ironic, you see, that any vampire would keep such a plant. I have written a poem:

When vampires smell their Dracaena palm roses,
The seeds of destruction are under their noses."

"Look!" said Diego, staring at the bat.

It had begun shaking and smoking. Blood was seeping, then began pouring, out of its body openings.

"It has already started," Po said with surprise. "It is early."

"What's happening?" Hi asked, as they watched the bat smoke, shake, and bleed.

"The extract is a powerful coagulant," Po explained. "There is violent chemical reaction, clotting the blood, the vampire hemorrhages. Horribly. Sometimes it even explodes."

The bat exploded, splattering them all with blood and bits of flesh. Hi's three-piece suit was ruined.

Po smiled a bit sheepishly. "Which is why it pays to wear a lab coat," he said.

As Po and his guests washed up at the laboratory's sinks, McKay nodded toward one of the beakers of dragon's blood. "That extract," McKay said, "is utterly impractical."

"How so?" asked the doctor.

"The time required. You kill a vampire with a stake through the heart. That doesn't take six hours."

"Five hours and a half," Hi corrected him wryly.

"It was the first time it has happened so soon," Po said, as if that really mattered.

"It works with bats, Doctor Po," Hi said, "but what about humans?"

"I cannot be certain," Po replied, "with no human vampires to work on."

"Bats are mammals," said Diego, drying his face. "So are humans."

"Yes," Po said. "So the effect is possibly similar."

"How much extract would it take?" Hi asked, dropping his bloodstained coat and vest in the garbage.

"For humans? Quite a lot. You would need, I would say, one plant, at least four months old, for every three or four humans, to get them to hemmorrhage."

"Like I said: impractical," said McKay, wiping bat debris off a shoe.

"How about the cure, Doc?" Hi asked. "Perón said you're onto a vampire cure."

"Oh yes, the cure," Po said, smiling. "I cannot be sure of that either. But, again, if with bats it will work, why should it not work with humans?" Then he laughed.

"What are you laughing at?" Hi asked.

"The cure," Po said. "Wait till you hear what it is."

Hi patiently waited for Po to stop chortling.