Song Xibai sighed deeply.

“I know whose handkerchief this is.”

Dingxiang's eyes widened: "How did you know? It's just an ordinary handkerchief!"

“Look at this fabric. Ordinary palace servants certainly couldn’t afford it. Only the imperial concubines were entitled to it,” Song Xibai said in a low voice.

"There are quite a few high-ranking concubines in the harem, and there might also be trusted palace maids and nannies!"

Song Xibai pursed her lips: "Do you remember the names of the concubines in the harem?"

This Dingxiang really knows. She received training when she first entered the palace. The first rule was not to offend important people, so she had to remember the names and birth dates of her masters clearly.

Dingxiang counted on her fingers: "The Imperial Concubine is named Shu Ning, the Virtuous Concubine is named Lan Yufeng, the De Concubine is named Zhu Yirou... There isn't one named Ying!"

Song Xibai closed her eyes.

"This is... the Empress's name."

The empress has been dead for many years, and no one in the palace talks about her anymore.

Even some of the older nannies and aunts had almost forgotten the Empress's name.

Song Xibai remembered it because the Crown Prince had shown her the Empress's memorial tablet.

Zhou Luanying.

There are many taboos regarding names in the palace.

Servants must not share the same name as their masters.

Although the empress had passed away many years ago, she was still the empress, and no palace servant dared to use any characters from her name.

Given that this was sent by Consort Shu, it can be basically concluded that this is the Empress's handkerchief.

Dingxiang also understood, and a look of sudden realization appeared on her face.

"But I still don't understand, why did she give it to me? Since it's the Empress's handkerchief, shouldn't it be given to His Highness the Crown Prince?"

"Perhaps she doesn't trust Mr. Jin and his group, and suspects that there's someone else behind them. But you're someone close to me, so she must have recognized you, which is why she secretly gave it to you."

Song Xibai guessed it pretty accurately.

Back in the Eastern Palace, Dingxiang, a palace maid skilled in medicine, was quite famous in the harem. At first, she only treated the young palace maids in the Eastern Palace, but later, palace maids from other palaces would also secretly come to her for treatment.

Consort Shu had been keeping a close eye on the Eastern Palace; how could she not know?

She didn't trust any men, even those who made various promises to Mr. Jin.

"The blood on this handkerchief must be the Empress's. It is very likely that it was the blood she vomited before she passed away."

Song Xibai pondered.

Unfortunately, after so many years, no matter how skilled she is, she can't extract any blood from it.

Just as Song Xibai sighed, her eyes suddenly paused.

"Wait! Dingxiang, come and take a look. Isn't there something greenish on this bloodstain?"

Dingxiang craned her neck and peered closely for a long time before finally nodding affirmatively.

"It is a bit green."

A glint of light flashed in Song Xibai's eyes.

"Could it be some kind of poison?"

On a whim, she grabbed Dingxiang's hand.

"Go quickly and find Physician Sun to see what kind of poison is on this."

"It's been more than ten years. Even if it's poisonous, it wouldn't be detectable, would it?" Dingxiang scratched her head, full of questions.

"If it's poison from plants or insects, then it's indeed impossible to detect. But what about other things?"

"The others?"

"For example, cinnabar, mercury, lead powder... should be in this category."

This refers to heavy metal poisoning.

Song Xibai rewrapped the handkerchief and reminded her, "Remember to wash your hands with bath soap."

Dingxiang took the handkerchief and went out.

Dingxiang returned even faster than Song Xibai had expected.

To Song Xibai's surprise, Physician Sun also came along.

As soon as Physician Sun entered, he didn't even bother with proper etiquette and hurriedly asked questions.

"Where did you obtain this item, Madam?"

"Please sit down, Physician Sun. This is a long story. Someone brought this here, and I don't know where it came from, but the bloodstains look a bit strange, so I wanted to ask you for your help."

Song Xibai spoke gently and gestured for Physician Sun to enter.

She can get out of bed now, but the weather is getting colder and colder, so everyone is keeping her from going out.

After Wei Hong brought over the tea, Song Xibai personally brewed tea for Physician Sun.

"Please don't mind the simple and humble dwelling."

Physician Sun waved his hand: "I have stayed in all sorts of dirty and messy places while traveling. Madam, there is no need for this."

The subtle aroma of tea filled the room, dispelling Physician Sun's anxiety and impatience.

He took the initiative to speak.

"I have traveled to many places and once discovered a strange disease in a village in the west. The people there often suffer from headaches, restless sleep, mental confusion, and some even have uncontrollable tremors in their hands and feet, loss of appetite, inexplicable pain in their bodies, and even large amounts of hair loss."

"I stayed there for a long time, trying to find a cure, but I couldn't find one."

At this point, Physician Sun looked somber and dejected.

Song Xibai already had a guess in her mind.

She pondered for a moment, then asked in return, "Is there a mineral vein nearby?"

Physician Sun exclaimed in surprise, "How did you know, Madam? That place, though called a village, is actually the descendants of some criminals. The mountains there are rich in minerals; as far as I know, there are several types of lead, pyrite, and brass."

Do the locals have any special eating or drinking habits?

Song Xibai asked again.

This time, Physician Sun thought about it for a long time.

"If you put it that way, the people in that village especially like to bake food with mud, and they also make mud cakes to eat during festivals. I asked them, and they said that there was a drought that caused food shortages and many people starved to death. Many people survived by eating a certain kind of mud. Later, in order not to forget those days, they would make this kind of mud cake during festivals."

Song Xibai's brows relaxed slightly.

It seems to be thallium poisoning.

However, thallium has not yet been discovered in this dynasty; it is only found scattered in soil and ores.

The village is surrounded by many mineral veins, and the soil contains a lot of thallium. Eating it for a long time will definitely cause problems.

She explained it to Physician Sun in detail, but didn't explicitly say what it was.

After hearing this, Physician Sun slapped his thigh: "It really is related to that soil?! I had suspected this before, but the locals didn't believe it! Alas! This time I must persuade them to change this custom."

Song Xibai stopped him with a smile.

"Physician Sun, please don't rush. Could you tell me more about that village? How many years has it been built? Since they are descendants of criminals, surely the government has a register of them? There shouldn't be any escapees, right?"

Physician Sun was puzzled: "Although that place is a place of exile for criminals, there are also ordinary people. Not all the people living in the village are descendants of criminals."

"How many years ago did you go there?"

"About eight or nine years ago, I think? I was also drawn in by the talk of that strange disease."

As Physician Sun spoke, his eyes suddenly lit up.

“Now that you mention it, I’m reminded of something. There are many people in the village, but very few able-bodied men. They worship a strange god there. When a child is about five years old, a messenger from the god will come and choose a child with good talent. These children rarely come back after they leave, but many years ago, one child did come back.”