Chapter 358: The Physician Writes Doctor Cai’s Medical Canon

The next morning...

In the central hut, a fire crackled in the brazier. A raincoat hung on the wall, and fishing gear leaned nearby. Inside, only an old man and a calico cat lay by the fire.

The old man prodded the fire with an iron rod, occasionally glancing down at the cat.

The cat, in turn, raised its head and silently observed the old man.

“You're called Lady Calico?”

The old Snake Immortal was the first to break the silence, shifting his gaze and asking.

“That's right!” The cat continued to stare at him, replying with a serious tone.

“When did you meet him?”

“It was in the afternoon!” the cat answered with precision. “Right when the sun was about to set!”

“What year?”

“It was called the first year of Mingde...”

“And where?”

“In a temple.”

“A temple?”

“My temple!”

“Your temple?”

“I was originally the Cat God, helping people catch mice. But the gods of the Heavenly Palace wouldn’t allow me to remain the Cat God...”

“So he took you away?”

“He invited me to travel the world with him so that he wouldn’t be lonely,” the cat replied seriously. “And I agreed.”

“Did you want to go with him at the time?”

“I agreed!”

“I see.”

The Snake Immortal nodded calmly, his gaze flickering briefly as if some thought crossed his mind. After a moment, he asked, “How old are you?”

“I don’t know.”

“You don’t know?”

“The Daoist priest said I have a very long lifespan, so there’s no need to worry about age. He also said Lady Calico was born free, so she can be however old she wants to be.”

“A long life isn’t necessarily a blessing...”

“Why not?” The cat looked puzzled. Living a long time sounded so peaceful and carefree.

“...”

The Snake Immortal shook his head without elaborating further. Instead, he asked, “How many years has it been since you’ve achieved enlightenment?”

“I don’t know.”

“You don’t know that either?”

“At that time, I didn’t know how to count.”

“And how long has it been since you’ve been able to transform into human form?”

“One, two... six years!”

“Then you’re still young, with a long future ahead.”

“I’m a big cat already!”

“Haha...”

The Snake Immortal couldn’t help but chuckle, shaking his head. Talking to this little cat turned out to be quite amusing.

But a sudden thought struck him—finding conversations with youngsters amusing might just be a sign of growing old.

At that moment, the cat spoke up again, asking, “You’re called Snake Immortal?”

“Call me whatever you like.”

“How did you grow to be that big?”

“Hm?”

“That big...”

The cat briefly pulled a paw out from under her chest to gesture the length and width, then tucked it back under herself, looking up at the old man with a steady gaze.

“Ah, that,” the Snake Immortal said, understanding her question. He smiled and replied, “It’s normal for a demon’s true form to be larger than ordinary animals. I’m old—I’ve lived for hundreds of years. Snake demons are a bit special, so my true form ended up this large.”

“What’s so special about snake demons?” The cat’s tone was serious, as though the topic were of grave importance.

“Ordinary animals grow until they reach adulthood, and after that, they stop growing. In old age, they might even shrink or lose mass. But snakes are said to carry the bloodline of dragons, so they keep growing throughout their lives.

“Even an ordinary snake will keep growing continuously until it dies of old age, though it will grow slower with each passing year. Once a snake becomes a demon, however, it will grow much larger with ease,” the Snake Immortal explained in his unhurried tone.

“Can I learn it?”

“It’s innate. You can’t learn it.”

“Then how big can a cat grow?”

“...”

The Snake Immortal turned to look at her, meeting her gaze.

The old man’s eyes were somewhat clouded with age. The cat’s pupils, however, were crystal clear.

In those eyes, the Snake Immortal saw no trace of worry. It seemed she had never once considered the inevitable disparity in lifespan between a demon destined for deep cultivation and a Hidden Dragon Temple cultivator. Her pure, bright gaze suggested that the young Daoist outside, currently washing his face, had done an excellent job of shielding her from such concerns.

This was, naturally, a good thing.

The Snake Immortal said nothing at first, only pondering for a moment before replying, “I recall Hidden Dragon Temple has several techniques that allow one to grow larger—some temporarily, and some permanently.”

“The Daoist priest said that too!”

“Then what are you worried about?”

“I...”

Before she could finish her sentence, her Daoist companion’s voice called from outside, “Time to go.”

The cat swallowed the rest of her words, sprang to her feet, and turned to the Snake Immortal. “I have to go now! I’ll talk to you again when I come back!”

“We’ll see,” the Snake Immortal replied.

“We’ll see?”

“It depends on fate.”

“Off I go!” The calico cat shook her head and began to stride out.

With each step toward the door, she moved farther from the warmth of the brazier. The cold grew heavier with every stride. By the time she slipped through the wooden door, the outside world was a frozen expanse of ice and snow.

A biting wind struck her, making her shiver before she lifted her head to spot the Daoist and the jujube-red horse ahead. Glancing up at the swallow circling the sky, she quickened her pace and dashed forward.

When she reached the Daoist, she slowed her steps, trailing behind him. With each small, struggling step in the snow, she left tiny holes in her wake.

Inside the hut, the Snake Immortal watched as they disappeared into the distance.

The Snake Immortal suddenly smiled, as if sensing a touch of sweetness in his heart. Perhaps the reason older people enjoyed talking with children was to absorb a bit of their innocence, to balance out the complexities and sorrows of their own lives.

***

The mountain was engulfed in a snowstorm.

“It’s a good thing you’re here,” Song You said as he patted the neck of the horse walking beside him. “Doctor Cai probably has some belongings he’ll need to bring over. Without you, relying on his old donkey alone wouldn’t be enough for a single trip.”

“

Snort

...”

The horse lifted its head, snorting loudly.

Meanwhile, the calico cat trudged through the snow, each step more laborious than the last, yet she stayed close behind.

Seeing this, Song You remarked, “I told you we’re just going to pick up Doctor Cai. If all goes well, we’ll be back by this afternoon. Even if it takes longer for him to pack, we’d return at most by tomorrow. The wind is strong, the snow is heavy, and walking tires you out. It’s freezing cold, and your paws must be freezing. But even when I asked you to wait back at the hut, you refused.”

“I’m not afraid of being tired or cold!”

“Is that so...”

“Exactly!” The cat spoke with conviction, looking up at him as she walked, though each step sank her into the snow up to her thighs.

As they pressed on, the horse ahead suddenly stopped. Lady Calico also stopped, lifting her head to see what was happening. The next moment, the horse lowered itself to the ground.

Soon after, the calico cat was perched atop the horse’s back. She chatted with the Daoist as they continued walking, recounting her conversation with the Snake Immortal back at the hut.

By midday, Song You once again knocked on Doctor Cai’s door. Under the watchful eyes of the physician and his two disciples, Song You explained, “I’ve spoken with the Snake Immortal. He admires your virtue and agrees that the publication of the

Medical Canon

is a great boon for the people. He has consented to let you finish your book in his fishing hut, where you will be safe and undisturbed.”

“This... does this mean...”

Doctor Cai’s eyes widened, clearly understanding that even the Snake Immortal believed the destruction of the

Medical Canon

might be related to divine interference.

“As long as you’re willing to complete the

Medical Canon

, you may do so at his hut without worry,” Song You assured him before adding, “However, there is one condition.”

“Please, do tell.”

“The Snake Immortal noted that, as a snake, he is naturally concerned about the use of snakes in medicine. While items like shed snake skins and eggs are acceptable, using snake bile requires killing a live snake. Moreover, the medicinal use of snake bile carries certain risks. As a trade-off, he hopes you will exercise caution when documenting the use of snake bile in your work. What do you think?”

“The Snake Immortal is absolutely correct. Using snake bile in medicine does indeed carry risks, as it can sometimes leave patients vulnerable to parasitic infections. I have long been researching alternatives,” Doctor Cai replied thoughtfully. “You and the Snake Immortal didn’t need to remind me about this. In fact, since being sheltered by the Snake Immortal in Mount Beiqin, I’ve rarely used snake bile in my practice.”

“That is for the best.”

“It’s just about lunchtime, and the meal is ready. Please, sir, stay and have lunch with us before heading out. It’ll also give us time to pack our things,” said Doctor Cai.

“It’s no rush,” Song You replied with a smile. “I’m in no hurry to head back down the mountain. Doctor Cai, take your time packing. Once we’re at the hut by the lake, for safety’s sake, I’d also like to request that your two disciples transcribe the remaining first half of the

Medical Canon

again, splitting it into two copies.

“One can remain in the hut, both for the Snake Immortal to safeguard and as a reference for continuing the second half. The other I’ll take with me—let’s see if certain gods dare make any sneaky moves against me.”

“Transcribing will take some time. Even if the two of us work nonstop, it’ll take at least ten days,” one of the disciples said.

“No hurry, no hurry. It’ll be a good chance to enjoy the mountain snow, perhaps emulate the Snake Immortal by fishing from a boat, or chat with him over tea in the deep mountains, reminiscing about the stories of my sect,” Song You said with a smile.

“Thank you, sir!” Doctor Cai bowed deeply in gratitude.

Not long after, the disciples brought out the food: a pot of plain congee, a plate of fried eggs, and a dish of walnut blossoms dressed in soy sauce—simple but flavorful.

The disciples ate only a few bites before hurrying off to pack. Song You reminded them that he had brought a horse, and since they might need to stay at the lake hut for over a year, they should bring not only pens, ink, paper, and dried provisions but also any other essentials for daily life.

He encouraged them to pack as much as possible for the winter, so they wouldn’t need to make another trip until the snow melted in spring or clear weather allowed for safe travel.

They set out in the afternoon and returned to the hut before dusk. By then, the Snake Immortal had already left.

Song You helped them tidy up the hut, repairing a damaged section of the roof and heading into the deep mountains to carve tables and stools from ancient wood, ensuring they had furniture suitable for writing and transcribing.

From then on, he stayed at the hut, waiting for the disciples to complete the transcription of the first half of the

Medical Canon

.

Doctor Cai wrote daily, almost without rest.

The disciples were similarly tireless, working with near-obsessive focus to transcribe the text.

Since Song You had free time, he often ventured into the mountains to visit the Snake Immortal, chatting over tea. Other times, he descended to the village to buy supplies—chickens and ducks for eggs, grains, dried meats, and stationery—for Doctor Cai and his disciples. He frequently reminded them to take care of their health and not overexert themselves.

Even Lady Calico helped out, visiting the hut each evening at their request to use her powers to light their lamps.