In the courtyard of the military medical camp, Lao Sun's senior disciple, Sun Shi, was crouching by the edge of the well.
Sun Shi had just finished changing twenty sets of medicated cloth in the wounded soldiers' tent, and his arms were so sore he couldn't lift them.
His throat was so dry it felt like it was smoking. He casually grabbed a rough porcelain bowl by the wooden bucket and scooped up a full bowl of well water.
The well water was clear and cold, with two pieces of grass debris of unknown origin settled at the bottom of the bowl.
Sun Shi didn't care, and raised it to his mouth.
Before the rim of the bowl even touched his lips, a figure darted in through the camp gate.
Lao Sun was barefoot on one foot, his clothes stained with vomit, and his hair half loose.
"Put it down!"
Lao Sun's shout startled the several medicine boys drying herbs in the courtyard.
Before Sun Shi could react, Lao Sun had already rushed in front of him and slapped the back of his hand.
The porcelain bowl flew out of his hand, flipped twice in mid-air, smashed onto the stone slab by the well, and shattered into seven or eight pieces with a crack.
Well water splashed all over Sun Shi's face.
"Master... Master?" Sun Shi wiped his face blankly, looked at the broken porcelain on the ground, and then looked at Lao Sun's bare foot. "Where's your shoe?"
"Never mind the shoe!" Lao Sun grabbed Sun Shi's collar and pulled him away from the edge of the well. "How much did you just drink? Tell me! How much did you drink!"
Sun Shi was pulled so hard he staggered two steps, almost falling into the herb-drying basket.
Finally steadying himself, his face was full of grievance.
"Your disciple hasn't drunk any yet. With that slap of yours, the bowl shattered."
Lao Sun first breathed a sigh of relief, then his eyes widened again. "You didn't drink? Then what did you drink this morning? What did you drink last night? Tell me the truth!"
Sun Shi stood frozen in place.
"Master, this morning your disciple scooped water from the vat in the back kitchen. Last night I boiled medicine until midnight, and when I got thirsty, I poured half a bowl of herbal tea from the clay pot..."
The more Sun Shi spoke, the more aggrieved he felt, and his voice trembled.
"Your disciple has been under your tutelage for eleven years, following your instructions strictly every day. I have never made a mistake with a single ingredient in a prescription, nor have I ever cut corners in preparation. What's wrong with you today?"
The medicine boys nearby shrank behind the herb-drying racks, peeking out, none daring to make a sound.
Lao Sun opened his mouth, but couldn't utter a word for a long time.
He wanted to tell his disciple what was in that water—
Those wriggling live maggots?
Those insects dragging long whiskers and burrowing in the mud and sand.
He had seen them rolling under that microscope with his own eyes; thousands of them lived in every drop of unboiled water.
But when the words reached his lips, Lao Sun found he simply couldn't say them.
What could he tell Sun Shi? Talk about evil spirits? Talk about foul poison?
Talk about the old teachings of the ancestors regarding evil spirits invading the body? He had just vomited all the sour water in his stomach before he realized that all of that was bullshit.
The things that really killed people, he couldn't name.
He only knew they were in that drop of water.
Alive.
"Master, why are your hands shaking so much?" Sun Shi supported Lao Sun's arm, his face pale. "Did something happen over at the wounded soldiers' camp? Or did that Valley Master Su from the blacksmith shop again..."
"Don't mention Su Mu." Lao Sun grabbed Sun Shi's wrist, his grip so tight that Sun Shi grimaced. "Listen to me, Master has no time to reason with you today, nor can I explain it clearly."
Lao Sun let go of his disciple, turned around, and scanned the medicine boys peeking out in the courtyard, saying sternly, "All of you, come here!"
Five or six medicine boys shoved each other into the middle of the courtyard, lining up in a row, all with their heads down, not daring to make a peep.
Lao Sun pointed to the wooden bucket for drawing water. "From now on, the well water in this bucket is only allowed for washing up and doing laundry. If anyone dares to use it for medicine, boiling soup, or making porridge, I will chop off their hands myself."
Sun Shi cried out involuntarily, "Master! Successive generations of sages have drunk this well water, and our military medical camp has drunk it for so many years? How can you..."
"Successive generations of sages?" Lao Sun turned and glared at him. "Successive generations of sages said evil spirits invade the body, successive generations of sages said water and soil are incompatible."
"Successive generations of sages taught us to boil medicine with unboiled water and pour it down people's throats, but from the bottom of your heart, did successive generations of sages cure more soldiers, or did more die?"
Sun Shi shuddered all over.
Sun Shi didn't dare answer, because he remembered clearly.
Over the years, of the wounded soldiers who died under his care, seven out of ten died from a high fever that wouldn't break, and the remaining three died from wound suppuration.
The military medical camp's prescriptions were fully written out, and the medical principles were clearly argued, but people just couldn't survive.
Sun Shi thought that was fate.
Lao Sun suddenly slapped his forehead, remembering an old matter.
"During the Eastern Jin Dynasty, there was a health-preserving alchemist named Zhang Zhan who wrote a book called 'Essentials of Health Preservation', which clearly recorded—'Once boiled and drunk, there is no harm'!"
"Zhang Zhan said it hundreds of years ago, water must be boiled! But the physicians of the Great Qian all treated it as a leisure book on health preservation, who took it seriously? Who?"
The courtyard was dead silent.
Lao Sun bent down and picked up a piece of broken porcelain from the ground.
"From today on, the military medical camp establishes strict rules."
Lao Sun held up that piece of broken porcelain and loudly announced to the disciples filling the courtyard.
"First, all drinking water in the camp must be boiled in a pot, and can only be used after boiling for the time it takes an incense stick to burn."
"Second, cleaning wounds, soaking herbs and boiling soup, making ointments and applying poultices, all must use completely cooled boiled water. If anyone dares to mix in unboiled water directly, get out of the military medical camp immediately."
"Third, these rules not only bind you, but tomorrow, any soup or rice sent by the cooks over there, if it has touched unboiled water, dump it out in front of them and find the head cook to remake it."
Sun Shi became anxious. "Master, the cooks are under the jurisdiction of the Commander-in-Chief's office, on what grounds can we..."
"On the grounds of this old man's life!" Lao Sun spat out flying saliva. "If Commander Tie Lanshan asks, this old man will kneel and tell him!"
Sun Shi stood frozen on the spot, looking at his master's stubborn and crazy face, feeling that his master must have suffered some great shock.
Sun Shi didn't dare talk back anymore, swallowing that highly disrespectful sentence back down—Master, have you perhaps been possessed?
...
Over at the blacksmith shop, Jenny Huang was standing in front of the microscope with her arms crossed, her cheeks puffed up high.
Su Mu was pacing back and forth beside her, holding pieces of paper covered in notes, muttering to himself:
"Boiling water can inactivate them, but those fine dregs in the water are still there. If the dregs enter the stomach, although it won't cause immediate trouble, if they accumulate over time, I'm afraid it won't do..."
"Can you give it a rest for a while." Jenny Huang kicked an empty charcoal basket over with her foot. "I haven't closed my eyes for three days and ground two good lenses, but you can't even speak a complete sentence smoothly."
Su Mu was just about to retort.
He saw Tie Lanshan striding into the blacksmith shop, still wearing his Commander-in-Chief's cloak, clearly having been dragged directly from the signing room by Li Sheng.
Li Sheng was panting from running in and out, and leaned against the wall as soon as he entered the door.
"Lord Xu, the Commander has been invited."
Tie Lanshan glanced at the messy blacksmith shop.
Scrap materials were scattered on the ground, optical path sketches were hung on the walls, and broken pieces of glass were piled up by the furnace.
Right in the center sat a yellow brass object.
"Has your place been ransacked?" Tie Lanshan frowned.
"Building a heavenly eye, Commander." Jenny Huang snorted from her nostrils. "The price is that this lady lost half her life."
Tie Lanshan ignored her nonsense and only looked at Xu Qinghuan. "Lord Xu called me here just to see this brass contraption?"
Xu Qinghuan went to meet him and reached out to guide him to the microscope.
"Commander, look first, and after you've seen it, we'll talk about the rules."
Xu Qinghuan placed the thin glass slide carrying the boiled water sample onto the stage, personally adjusted the height of the lens tube for Tie Lanshan, and then took a half-step back.
Tie Lanshan took off his iron helmet, set it aside on the desk, and leaned over.
At his first glance, Tie Lanshan's brow furrowed heavily.
There were no living creatures in his field of vision.
Tie Lanshan had never seen what these living creatures looked like anyway.
But he clearly saw the things deposited at the bottom of the glass slide—a dense array of dead, ashen specks, along with tiny debris trapped in a transparent, gel-like liquid, completely motionless.
Xu Qinghuan didn't let him look for too long. As soon as Tie Lanshan straightened up, she dropped a drop of unboiled water, scooped from the water vat in the courtyard, onto the slide.
"Please take another look, Commander."
Tie Lanshan leaned over again.
This time, Tie Lanshan completely froze.
The previously quiet and dead water was now teeming with darting black shadows.
Living creatures.
Countless wriggling living creatures.
Tie Lanshan took a large step back.
Three breaths passed.
Four breaths.
Tie Lanshan turned back and looked a second time.
He looked even longer this time, so long that Su Mu, standing nearby, scratched at the edge of the desk in anxiety. Tie Lanshan finally straightened up, his Adam's apple bobbing several times before he asked hoarsely, "These things... are in the water?"
"In every drop," Xu Qinghuan said calmly.
Tie Lanshan turned to look at the half-human-tall water storage vat in the corner of the courtyard.
Tie Lanshan remained silent for a long while before speaking again, "There are no living creatures in boiled water?"
"You saw it with your own eyes, Commander. Do I need to say more?"
Tie Lanshan closed his eyes.
Having led troops for many years, he considered himself especially wary of epidemics.
The iron cavalry of the Helian people hadn't trampled the entire camp, but a single plague in the camp had rotted away half the troops of the logistics division.
From his youth until now, Tie Lanshan had seen far too many soldiers with festering, pus-filled wounds or driven mad by high fevers.
The military doctors always blamed it on miasma, poisonous vapors, or unacclimatization.
To hell with unacclimatization.
It was the things in this vat.
Tie Lanshan opened his eyes and looked at Xu Qinghuan. "Lord Xu, having me look through this 'Heavenly Eye' today wasn't just to broaden my horizons."
"I came to ask the Commander for some orders. The first order: drinking unboiled water is strictly prohibited throughout the entire camp. The wounded soldiers' camp, the logistics division, the accounting tents of all battalions, and even the personal guard battalion of the Commander-in-Chief's estate must all comply." Xu Qinghuan walked to the desk and picked up the cup of tea that had already gone completely cold.
"The second order: I want to build a few simple water purifiers in the military camp."
"What purifiers?" Jenny Huang asked, jumping in before anyone else.
Xu Qinghuan continued speaking on her own.
"Saw off two-thirds of a wooden barrel and stack them in layers. The top layer is paved with clean sand, the middle layer is filled with charcoal granules and crushed stone, and the bottom layer leaves a gap for water to flow out."
"Pour the water into the top layer. After passing through the sand filter and the settlement of dirt and stones, clean water will flow out."
"Although this water still cannot be drunk directly, drinking it after boiling is much cleaner than boiling muddy water directly."
"That's roughly it..."
Xu Qinghuan secretly rejoiced in her heart—
Good thing I watched so many survival shows in the past...
Jenny Huang was stunned.
Su Mu cried out first, "Charcoal granules can absorb fine debris? Fine sand can intercept bugs?"
"We'll know once we try."
Xu Qinghuan put down the cup and looked at Tie Lanshan.
Tie Lanshan lowered his head, looking at the faintly reflecting lens of that brass microscope, and then shifted his gaze to the words Xu Qinghuan had written on the desk: "Microscopic World."
Tie Lanshan suddenly took off the Commander-in-Chief's seal from his waist and slammed it onto the desk with a loud bang.
"Pass down my order, all armies hear my command! From tonight onwards, drinking unboiled water is prohibited throughout the entire camp. Those who violate the order..." Tie Lanshan paused, glanced at Xu Qinghuan, then withdrew his gaze and continued, "Those who violate the order will be punished by emptying chamber pots in the wounded soldiers' camp for twenty days!"
Jenny Huang burst into laughter.
Li Sheng muttered softly to the side, "The Commander's method of punishment is truly wicked."
