Jessa set two samples on opposite sides of the assay table. One came from the suspect bottle. The other was a control mixture made from the ordinary ingredients named in the medicine catalog. Tessa placed a third vial between them, measured from the same bottle by a separate pipette. The seal and sample numbers were visible from the door.
“Nothing goes back into the bottle,” Qinghe said. “We keep each sample separate.”
Jessa nodded. “The first test showed the extra uptake. Now we test the ingredients we know and check what remains.”
She poured one drop of the control into the neutral solution. The liquid rose a little, then settled. Tessa marked the height on a glass slip. They repeated it with the suspect sample. The line climbed farther, held, and eased back into the vial.
“More than the usual tonic,” Tessa said. “But the catalog lists several compounds that could do that.”
Gu He entered with the old medicine catalog under one arm. He had spent the morning checking licensed formulas from the district archive. “This entry is for a recovery tonic,” he said, turning to the marked page. “The compound can increase short-term qi uptake. At high frequency, it can create reliance on repeated doses.”
