A divine healer, a general, a young marquis! Who can rival them!

On the morning of the fourteenth day, the first person to die in the city, not from being beaten to death, died.

He was a water carrier and cook. He was fine the night before, but developed a high fever in the middle of the night and collapsed by dawn. When they carried him to the wounded soldiers' camp, Yang Hu opened his eyelids, examined his tongue, and questioned the people in his tent.

Those in the same tent said that seven or eight people in the camp had stomach problems in the past two days, at first they just thought it was because they ate spoiled food. After a siege of half a month, the food was mixed with bran, and no one's stomach was feeling well, so nobody took it seriously.

Yang Hu asked one last question: Were those seven or eight people all drawing water from that well to the north?

The person in the same tent thought for a moment and agreed.

Yang Hu stood up, his expression changing.

"Separate all the people in this tent."

Physician Liu was stunned: "Physician Yang, only one has died..."

"Only if one person dies can we keep them at bay."

"Medical Officer Yang..."

"Seal it off completely. No one is allowed to enter or leave."

By the afternoon, the number of people with stomach upset had increased from seven or eight to thirty-one.

By dusk, there were one hundred and forty-six.

Physician Liu's hands trembled so much he could barely hold the pen: "What...what kind of symptoms are these?"

"Epidemic".

Upon hearing those two words, the doctors in the camp turned pale.

Physician Liu subconsciously took half a step back, then abruptly pulled his foot back. He had practiced medicine for half his life, witnessed epidemics, and seen how they ended. That wasn't treatment; that was waiting. Waiting for it to burn out on its own, waiting for the survivors to carry the dead out.

After a fourteen-day siege, the city still had enough food, medicine, and morale was not low. But those two words, when applied, were far more devastating than a barbarian's catapult.

"Where did you come from?" This was the first question Wang Duwei asked when he arrived at the camp.

Yang Huxian did not answer. He led Commandant Wang to the foot of the north city wall and pointed outside the wall.

"Three miles away, the barbarians have piled up dead bodies for two days."

Commandant Wang's expression changed instantly.

"The wind comes from the north," Yang Hu said. "But the body is three miles away, and the wind can't carry the news that quickly. What travels fast is the water."

He turned and headed north of the city.

There are three wells in Qingshikou. The northern well is the largest, serving more than two thousand people from the eastern and northern sections.

When Yang Hu arrived at the well, he squatted down and looked at it for a long time.

The well was less than thirty paces from the north city wall. Beyond the wall lay the direction from which the barbarians had piled up corpses over the past fourteen days.

"Bring up a bucket."

The water was drawn up and it was clear. It didn't smell strange either.

Yang Hu did not drink it. He asked someone to bring a bowl, scooped out half a bowl, and placed it in the sun.

"Watch for half an hour."

The sun was blazing. The half-bowl of water, placed on the bluestone slab, was so hot that the rim of the bowl was burning.

Half an hour later, a very fine layer of turbidity sank to the bottom of the bowl.

"This well can no longer be used."

"Can't be used?" Captain Ma almost jumped up. "More than two thousand people rely on this one well! If we seal it off, what will the people in the eastern and northern sections drink from?"

"Drink from the South Well and the West Well."

"Those two wells combined don't even produce half the water in a day!"

"If it's not enough, then we'll cut back." Yang Hu stood up. "Two bowls a day for each person, boiled and drunk. For washing, rinsing the pot, and wiping the body, use water from the moat, but absolutely no one is allowed to drink it."

"Our brothers have been baking in the sun all day on the city walls, only getting two bowls of water a day?" Commander Wang said in a deep voice, "How can we fight this battle?"

"Thirst won't kill you," Yang Hu said, looking at him. "This epidemic, however, can kill half the population."

Commandant Wang remained silent.

"Half." Yang Hu picked up the half-bowl of muddy water and held it up to him. "There are currently 2,100 people in the city who can stand. If we ignore this bowl of water, in twenty days, there will be less than a thousand people standing on the city walls. The barbarians won't even need to attack."

He put the bowl down.

"If we seal the well, we'll lose two bowls of water every day. If we don't seal the well, the city will be empty on its own after a month."

No one spoke inside the tent.

Yang Hu changed those six rules into nine.

The North Well was sealed off that day, the wellhead was covered with a stone slab, and then soil was piled up.

All the water in the city was boiled. All the pots in the city, including those from the distilleries and tofu shops, were requisitioned and set up against the city walls, running day and night.

Those with stomach aches or fevers were all moved to the empty camp in the south of the city, isolated from others. The caretakers had to dip their hands in a basin of boiling water before entering or leaving.

Those who have died must not be buried in the city; they must all be burned.

The excrement was cleaned up twice a day, transported to the ditch outside the south wall, and lime was spread on it.

Flies are the most important thing. All open water vats and porridge buckets in the city must be covered; ash from mugwort must be sprinkled in the open areas of the camp, and the tents must be fumigated every day.

Those with minor injuries and those with serious injuries should be housed separately, with no more than twenty people allowed in one shed. Those who provide care and meals should each stay in their own shed and are not allowed to visit each other.

Anyone leaving the South Camp had their clothes boiled in a pot, and they were only allowed to leave after washing their hands in the basin of water at the door.

……

None of these rules were found in military orders. Yet, in the fourteen days since Qing Shi Kou began, no one had asked about the phrase "unheard of" anymore.

On the fifteenth day, 302 people had stomach upsets.

On the sixteenth day, there were 417.

The seventeenth day, three hundred and eighty-eight.

For the first time, the numbers went down.

Yang Hu drew line after line on the wall in Yingkou with charcoal. One line a day, drawing lines for every person who had an upset stomach.

For the first three days, the path grew longer and longer each day, almost reaching the top of the wall.

The one on the seventeenth day was shorter.

The eighteenth day was even shorter.

By the twenty-second day, only a short section remained of that streak, like a matchstick.

Every day when the soldiers guarding the city changed shifts, they would look up at that wall as they passed by. As more and more people looked at it, some began to say to others: "If that path is a fraction shorter, we can live a fraction longer."

The nineteenth day, one hundred and sixty.

The twenty-second day, the fifty-third.

That night, Commandant Wang found Yang Hu on the city wall.

"Over at the South Camp," he said, "six were carried out today. The day before yesterday, it was nineteen."

"Um."

"Medical Officer Yang," Commandant Wang paused for a moment, "I've served in the border army for twenty years and witnessed three epidemics. The first time, seventy percent of an entire battalion died. The second time, the camp was burned down. The third time…"

He didn't continue.

Yang Hu didn't ask.

"This time," said Commander Wang, "we lost three hundred and seventeen."

317.

It's less than a siege.

"If we followed the old methods," Commandant Wang raised his head, "how many should have died?"

Yang Hu thought for a moment.

"half."

More than a thousand.

There are now fewer than two thousand people left in this city who can stand. If we continue with the old methods, Qing Shi Kou will fall after this epidemic. The barbarians won't even need to attack anymore; they can just wait outside the city.

The wind was still blowing from the north.

But this time, the things carried by the wind were blocked layer by layer by the sealed well, the dozens of pots that burned day and night, and the fire that burned corpses.

On the twenty-third day, the barbarians outside the city finally made their move again.

The catapults were set up again, and the horns sounded all day.

That siege lasted until the sun was high in the sky above the city walls.

When the barbarians retreated, there were a thousand more people standing on the city wall than they had expected.

Meanwhile, in that shed for wounded soldiers, Su Heng was stuffing something she had just taken from a corpse into Yang Hu's hand.

It was a leather pouch that the barbarian always carried, containing a small handful of dried grass leaves.

Yang Hu poured the grass leaf into his palm, rubbed it between his fingers, and suddenly raised his head.

"This isn't their herb," ​​he said. "It's for treating dysentery."

Su Heng was taken aback: "You mean...?"

"There's also trouble in the barbarian camp," Yang Hu said slowly.

Su Heng held her breath.

"Thirty thousand men besieged the city for twenty-three days." Yang Hu gathered the dry grass leaves back into his leather bag, his fingers tightening little by little. "Their dead bodies were piled up three miles away, and their water also came from that area of ​​land."

"They don't have anyone to seal the well."

Su Heng slowly sat down.

During the 23-day siege, it was the first time she heard Yang Hu mention the 30,000 men outside the city, and he didn't use the word "fight".