“It is easy for us rural doctors,” Tse explained. “We use a very small catheter with a wire guide. It is done by feel. We do not need to see. It is not painful for the patient.”

“Marissa!” Tristan called. He had come back to the threshold of the examining room. “Come out here and see the garden. They grow their own medicines!”

But Marissa waved Tristan away. She stared at Tse, her mind racing. “Can Chi-Li perform this technique as well?” she asked.

“I’m sure,” Tse said. “All rural doctors are taught it.”

“Once you cannulate the fallopian tube,” Marissa said, “what do you use to sterilize?”

“Usually a caustic herbal solution,” Tse said. “It is like a kind of pepper.”

Tristan left the doorway and approached Marissa. “What’s the matter, luv?” he asked. “You look like you’ve just seen a ghost.”

Without saying a word, Marissa hurried back to the procedure room and walked up to the cabinet. She studied the shelf of vaccines.

Tristan followed her, wondering what she was thinking. “Marissa,” he said, as he reached out and grabbed her shoulders, swinging her around to face him. “Are you okay?”

“I’m fine,” Marissa said. “Tristan, I think I just figured it all out. All of a sudden I think I understand—and if I’m right, the truth is much worse than we imagined.”

The health clinic van took the four of them to Shigi and dropped them off at the Shigi bus station. Since there was frequent service to Forshan, they had only a short wait. During the trip, Marissa sat next to Tristan while Bentley sat with Tse.

“I’ve never seen anybody spit more than these Chinese,” Tristan said to make conversation. It was true. At any given moment someone on the bus was either preparing to spit or was in the process of spitting out the window. “What the hell is wrong with these blokes?”

“It’s a national pastime,” Bentley said, hearing Tristan’s comment. “You see it all over China.”

“It’s disgusting,” Tristan said. “It reminds me of that foolish American game of baseball.”

Everyone on the bus seemed to be busy talking except Marissa and Tristan. Tristan had finally given up after Marissa persisted in meeting his every question with only one-word replies. She seemed to be deep in thought.

Suddenly she turned to him. “Do you know the pH indicator phenol red?”

“Vaguely,” Tristan said, surprised by her sudden inquiry.

“When does it turn red?” Marissa asked. “In an acidic or an alkaline solution?”

“I think alkaline,” Tristan said. “In an acid solution it’s clear.”

“I thought so,” Marissa said. Then she lapsed back into silence.

They rode for another mile. Finally, Tristan could no longer contain his curiosity. “What’s with you, Marissa?” he asked.

“Why won’t you tell me what you’re thinking?”