godfather of surgery

Chapter 1389 Dr. Yuan's Second Visit
At six o'clock on Wednesday morning, Zaxi appeared in the institute's library as usual. This was the third day of the second phase of study that Yang Ping had assigned him, and he was working through a document on guidelines for the treatment of infectious aneurysms. On the table was an open notebook, with pathological classification diagrams of aneurysms drawn on the left and antibiotic treatment courses and discontinuation criteria written on the right, densely packed like a net being woven.

He has gradually grasped the learning method Yang Ping described—not rote memorization, but building a framework. Each time he reads a paper, he draws a mind map in his notebook, attaching the new knowledge points to the existing framework. Clostridium difficile infection is the trunk, infectious aneurysms are the branches, intracranial aneurysms are the larger crown… Inflammation, infection, the repair mechanisms of the blood vessel wall, the game between the host and the pathogen… He is learning to see these roots clearly.

His phone vibrated. He glanced at it and saw a message from Professor Yang: "Come to my office."

Zaxi closed his laptop and jogged quickly. Yang Ping's office door was open, but he wasn't alone. A middle-aged man in his early forties, dressed casually, sat on the sofa. He had a square face, thick eyebrows, and sat very upright; he was clearly not a doctor. Next to him sat a young woman, around thirty years old, with short hair, wearing metal-framed glasses, carrying a briefcase, and looking capable.

"Zaxi, come in." Yang Ping beckoned, then turned to the middle-aged man. "This is my student, Zaxi, from Tibet. He can be trusted."

The middle-aged man stood up, extended his hand, and said, "Hello, my surname is Yuan, I'm from the Provincial Public Security Bureau." His handshake was firm, his knuckles rough.

Zaxi was taken aback. The Public Security Bureau? He glanced at Yang Ping, who nodded slightly, gesturing for him to sit down.

The middle-aged man was Dr. Yuan from the Provincial Public Security Bureau. This was not his first time seeking advice from Yang Ping. The young woman next to him was his assistant.

Dr. Yuan didn't beat around the bush: "Professor Yang, we've run into trouble again. We were very grateful to you for your help with the last case. This time the situation is more complicated. We've thought about it for a long time, and we still have to ask you for help."

Yang Ping leaned back in his chair and said calmly, "Tell me about it."

Dr. Yuan glanced at the young woman beside her. She opened her briefcase, took out a stack of documents, and placed them on Yang Ping's desk.

Dr. Yuan introduced the woman next to him: "Xiao He, please give Professor Yang a detailed report."

Xiao He adjusted his glasses, opened the top document, and spoke in a clear and calm voice: "Case Summary: The deceased was a 62-year-old male, a retired professor from the Department of Chemistry at Nandu University, who lived alone. He was found dead at home three days ago. There were no signs of a struggle at the scene, the doors and windows were intact, and there were no signs of forced entry. The body had no obvious external injuries, and no abnormalities such as needle marks or ligature marks were found on the body surface. The preliminary autopsy did not find any fatal lesions, and toxicology screening is underway. So far, no common toxins have been detected."

She paused, looking at Yang Ping: "However, the deceased's posture at death was very strange. He died sitting at his desk in the study, his hands folded on the table, his head resting on his arms, as if he were taking a nap. There was a half-finished cup of tea on the table, and a book turned to a certain page. The study window was slightly ajar, but the screen was intact. The whole scene was very clean, with no signs of struggle or movement."

Yang Ping listened without changing his expression, and went straight to the heart of the matter: "Where is the point of contention?"

Xiao He and Dr. Yuan exchanged a glance. Dr. Yuan said, “There are three suspicious points. First, the deceased had always been in good health, had annual checkups, and had no history of cardiovascular or cerebrovascular diseases. A 62-year-old man with no chronic illnesses dying suddenly is suspicious in itself. Second, the deceased had just received a threatening letter a week before his death. The letter concerned a research project he participated in 30 years ago; we are still investigating the specific details. Third…” He hesitated for a moment, glancing at Xiao He.

Xiao He continued, "Third, the deceased's pupils. During our preliminary autopsy, we found that both of his pupils were extremely constricted, about the size of a pinhead. This is very rare in normal deaths. Opioid poisoning can cause pupil constriction, but the toxicology screening was negative. Moreover, if it were an opioid overdose, there would usually be respiratory depression, pulmonary edema, etc., but none of these were present."

Yang Ping's brow twitched slightly, and his pupils contracted sharply as he silently recited the words in his mind.

“There’s one more thing,” Xiao He continued, “The deceased’s fingers, the tips of all ten fingers on his hands, have obvious pigmentation, which is grayish-brown in color. The area is not large, but it is very symmetrical.”

Dr. Yuan continued, "I checked the literature, and this symptom doesn't have a clear diagnostic significance, but I feel it's abnormal, it's just a feeling."

Yang Ping's gaze fell on the stack of documents. He reached out and flipped to the first page, which contained a photograph of the scene. The deceased was slumped over the table, his posture indeed resembling a nap, peaceful beyond belief. The book on the table was open, and Zaxi leaned closer to take a look; it was an English version of "Advanced Organic Chemistry."

Yang Ping turned to the next page, which showed a close-up of the pupils. Both pupils were indeed extremely small, almost like dots.

He then flipped to a close-up of the fingers, where the pigmentation at the fingertips was very obvious, grayish-brown, distributed along the edge of the nails, present on all ten fingers, and very symmetrically.

"What about the complete on-site investigation report?" Yang Ping asked.

Xiao He pulled out an even thicker document from his briefcase: "It's all here, including on-site photos, an inventory list, door and window inspection records, and neighbor visit records."

Yang Ping took it and flipped through the pages one by one. He stopped when he got to the list of items.

Was there a computer in the deceased's study?

"Yes!" Xiao He said, "One desktop computer and one laptop. We checked them and found nothing unusual. His browsing history, emails, and documents are all normal. His search history in the past week only has a few entries, all about organic chemistry."

"Where's the phone?"

"A smartphone was also on site. Call logs, text messages, and WeChat messages were all normal. In the past week, there were only a few food delivery and courier calls."

Yang Ping nodded, continued flipping through the pages, and closed the document when he reached the last page.

“I need to go to the site and see for myself,” he said.

Dr. Yuan's eyes lit up: "Great! Professor Yang, when is a convenient time for you?"

Yang Ping glanced at his watch: "This afternoon, Zaxi, you're coming with me."

Zaxi was startled and nodded vigorously.

At 2 PM that afternoon, Zaxi and Yang Ping got into the Public Security Bureau's car. Dr. Yuan drove, Xiao He sat in the passenger seat, and Yang Ping and Zaxi sat in the back. After about forty minutes, the car entered a residential area in the old city of Nandu. The area was small, with only six buildings, all six-story walk-up buildings, painted a beige color and looking at least twenty years old.

The deceased lived on the fourth floor of Unit 4, Building 3, which had no elevator. The stairwell was clean, but dimly lit. Dr. Yuan walked ahead and used his key to open the door to apartment 401.

As soon as the door opened, Zaxi smelled a faint, strange odor. It wasn't the smell of decay, but rather an indescribable chemical smell, somewhat like organic solvents in a laboratory, and also somewhat like burnt plastic.

Yang Ping stood at the door, not going in immediately. He looked around, then squatted down and stared at the lock.

"Are there any signs that the door lock has been pried open?"

Dr. Yuan shook his head: "No, the technical department has checked it. The lock cylinder is intact and there are no signs of technical unlocking."

Yang Ping nodded and stepped inside.

The living room wasn't large, but it was very tidy. The sofa, coffee table, and TV cabinet were all arranged neatly. On the coffee table was a teacup with half a cup of water, a thin layer of ash floating on the surface. Next to it, in the ashtray, were two dried-out cigarette butts.

Yang Ping did not linger in the living room, but went straight into the study.

The study was smaller than the living room, only about ten square meters. A desk stood by the window, on which sat a half-finished cup of tea, an open copy of "Advanced Organic Chemistry," a desk lamp, a pen holder, and several pens. Behind the desk, a bookshelf lined the wall, crammed full of books, mostly chemistry textbooks, but also a few novels and essays.

Yang Ping stood in front of his desk, looking down at the surface. His gaze moved from the teacup to the book, then to the lamp, and finally to the pen holder. He picked up the pen holder, glanced at the bottom, and put it back.

Then he crouched down and looked at the floor under the desk. The floor was a light-colored wooden floor, very clean, without any marks.

"He died sitting right here?" Yang Ping asked.

Xiao He nodded: "Yes, when the forensic doctor arrived, he was lying face down on the table like this. When we lifted him off the table, his posture didn't change."

Yang Ping stood up and walked to the bookshelf. He glanced at the books on the shelf, then reached out and pulled one out. It was a workbook for "Advanced Organic Chemistry," quite old, with yellowed pages, but well-preserved, without curled edges or creases. He flipped through it; inside were some neat pencil notes.

He put the book back and pulled out another one. This time it was a book on "Organic Synthesis Route Design," also very old, and also very well preserved.

Zaxi stood at the door, watching Yang Ping's every move, not daring to breathe. He didn't know what Yang Ping was looking for, but he knew Yang Ping must be looking for something.

Yang Ping suddenly asked, "Did the deceased have a habit of keeping a diary during his lifetime?"

Dr. Yuan was taken aback: "A diary? We didn't find a diary at the scene."

Xiao He thought for a moment and said, "There are no diary files on his computer, and we didn't find any handwritten notebooks either. But we found some scattered sticky notes with some memos written on them, but they were all very brief and didn't contain much information."

Yang Ping nodded without saying a word. He walked to the window, opened it, and glanced outside. There was a small courtyard with a few trees, nothing particularly special.

"Where's the screen?" he asked.

“It’s intact!” Xiao He said. “We’ve checked it; there’s no damage or signs of disassembly.”

Yang Ping closed the window, turned around, and his gaze fell on the open book on the desk. He walked over, glanced down at the open page, and saw some faint pencil markings.

He stared at that page for a long time, then looked up and asked a question that surprised everyone: "What was the deceased's research area before retirement?"

Xiao He flipped through the documents in his hand: "Organic synthesis, specifically... asymmetric catalysis. He is one of the early pioneers in this field in China."

Yang Ping nodded, then asked, "Is his lab still there?"

Dr. Yuan said, "It's still there. The Department of Chemistry at Nandu University has a new laboratory, but the old one has been preserved and is now managed by one of his students."

Yang Ping was silent for a moment, then said, "I want to go and see his lab."

Dr. Yuan and Xiao He exchanged a glance. Dr. Yuan said, "Okay, I'll arrange it." As they walked out of the residential area, Zaxi finally couldn't help but ask, "Professor Yang, besides treating patients, you also help the police solve cases?"

Yang Ping shook his head: "Rarely. They only come to us when they need clinical medical knowledge during the investigation process, since forensic medicine is a weak point in clinical medicine."

After Yang Ping got into the car, Dr. Yuan asked, "Professor Yang, what did you discover?"

"Nothing has been found yet," Yang Ping said.

Yang Ping continued, “On his bookshelf, the bookshelf of a retired professor from the chemistry department, there are books like ‘Advanced Organic Chemistry’ and ‘Organic Synthesis Route Design,’ which is normal. But have you noticed how well the books on his bookshelf are preserved?”

Dr. Yuan didn't understand.

Yang Ping said, "It's impossible for someone who has spent their whole life working in chemistry, reading books every day, to be completely spotless. Chemical reagents would spill on the books, and chemicals from their fingers would corrode the pages. But his books were too clean. Those books seemed to be there for show, not for reading."

Yang Ping added, "If I remember correctly, organophosphorus compounds in clinical practice..."

Dr. Yuan's mind raced. Pupil constriction—organophosphates—he suddenly remembered: "Organophosphate poisoning can cause pupil constriction!"

Yang Ping glanced at him, a hint of approval in his eyes: "Yes! One of the typical symptoms of organophosphate poisoning is extreme constriction of both pupils. Also, organophosphate poisoning can lead to sudden death, and an autopsy may not reveal obvious organic lesions."

Dr. Yuan became excited: "Then you suspect he was poisoned?"

Yang Ping shook his head: "I don't doubt anything, I'm just looking for clues. The symptoms of organophosphate poisoning are not just constricted pupils, but also salivation, sweating, muscle tremors, and pulmonary edema, but these symptoms were not found in the autopsy report of the deceased."

Dr. Yuan was slightly disappointed.

Yang Ping said, "So, here's the problem. It looks like organophosphate poisoning, but it's not quite. The pigmentation on his fingertips doesn't match the symptoms of organophosphate poisoning either. So what is it?"

He leaned back in his chair and closed his eyes: "Let's go to the lab and see if we can find the answer."

Outside the car window, the streets of Nandu gradually darkened in the twilight. Zaxi sat in the back seat, his mind filled with questions. Organophosphate poisoning? But the symptoms didn't match. Pigmentation? What was that? The books on the shelf were too clean? What did that mean?
He took out his notebook and wrote down every clue Yang Ping had mentioned.

The Chemistry Department of Nandu University is on the other side of the city. The drive took forty minutes, and we arrived close to five o'clock. Dr. Yuan had given prior notice, and a young man was waiting at the school gate. He was around thirty years old, wore glasses and a white lab coat, and looked very refined.

“I am Li Xiong, Professor Zhou’s student.” He extended his hand, his voice very soft. “I used to manage that old laboratory, and I would sometimes use it when teaching students.”

Professor Zhou was the old man who had passed away.

Li Xiong led them through the main building of the Chemistry Department to an old laboratory building at the back. The building had only three floors, the paint on the exterior walls was peeling, and the corridors were filled with the smell of chemical reagents. Li Xiong used a key to open a laboratory on the second floor, pushed open the door, and found it dark inside. He fumbled for the light switch and turned it on.

The laboratory wasn't large, but it was fully equipped. Fume hoods, rotary evaporators, chromatography columns, and various glassware were all neatly arranged. On the workbench were several reagent bottles, each labeled with its chemical formula and date.

Yang Ping stood at the doorway and looked around. Then he walked to the lab bench and looked down at the reagent bottles. He picked up a bottle, looked at the label, and put it back. He picked up another one and put it back as well.

"Does Professor Zhou still come to the lab often after he retires?" he asked.

Li Xiong nodded: "Yes, he comes at least two or three times a week. He says he's bored at home and might as well come and do experiments."

What kind of experiment?

Li Xiong thought for a moment: "It's mainly about repeating some classic organic synthesis reactions. He said it's to maintain our feel for it. Sometimes we'll try some new things, but none of them are major projects."

Yang Ping nodded, walked to the fume hood, opened the door, and glanced inside. Several sets of glassware were inside, all clean and upside down on the shelf. In the corner was a small brown reagent bottle, different from the others; its label was handwritten, the handwriting very small.

Yang Ping reached out and took out the bottle. The label read: "Unknown object, pending identification, 2019.3".

He unscrewed the bottle cap and gently fanned the air around the opening. A faint, slightly pungent odor wafted out. Zaxi, standing beside him, also smelled it; it was very similar to the smell in the deceased's house, but much stronger.

Yang Ping tightened the bottle cap and placed the bottle on the lab table.

"Who put this bottle here?" he asked.

Li Xiong leaned over to take a look, then thought for a moment: "This... I'm not quite sure. Professor Zhou probably put it there himself. He sometimes synthesizes new compounds and puts them in bottles for later identification. But there are so many of these things, I haven't paid attention."

Yang Ping nodded without asking any further questions. He then walked around the lab again, looking at the literature on the bookshelves and the lab logbook, before finally stopping at the door.

"Has Professor Zhou shown any unusual behavior in the past six months?" he asked Li Xiong, "physically or behaviorally."

Li Xiong thought for a moment and said, "Physically... he's lost some weight recently, but it's normal for older people to lose weight. Behaviorally... he seems to be more silent than before. Before, when he came to the lab, he would chat with us for a bit, but in the last six months he hasn't said much and just keeps doing experiments by himself."

He paused, then suddenly remembered something: "Oh right, about two months ago, he asked me a very strange question."

Yang Ping's gaze sharpened: "What's the problem?"

Li Xiong said, "He asked me if an organophosphorus compound could be absorbed by a person if it was not inhaled through the respiratory tract or ingested through the digestive tract. I said that theoretically it could be absorbed through skin contact, but the absorption efficiency is very low. After listening, he nodded and didn't say anything more."

Yang Ping's expression remained unchanged, but Dr. Yuan noticed that his fingers twitched slightly.

"Thank you," Yang Ping said. "That's all for today."

By the time we stepped out of the lab building, it was completely dark. Dr. Yuan asked, "Professor Yang, what do you think?"

Yang Ping remained silent for a long time before saying, "I need to think about it some more. Let's do it tomorrow. I'll give you an answer tomorrow."

On the way back, the car was quiet. Zaxi sat in the back seat, his mind a jumbled mess. Organophosphorus compounds, skin absorption, pupil constriction, pigmentation, books on the bookshelf, mysterious reagent bottles in the laboratory—these fragments swirled in his mind, but he couldn't piece them together.

He glanced at Yang Ping, who was sitting with his eyes closed, leaning back in his seat, motionless.

Zaxi knew he wasn't asleep; he was thinking, pondering the connections between those fragments.

When the car arrived at the entrance of Sanbo Hospital, Yang Ping opened his eyes, got out of the car, and Zaxi followed behind him into the hospital gate.

When Yang Ping reached the bottom of the research institute building, he suddenly stopped.

"Zaxi, what did you see today?"

Zaxi thought for a moment and said, "A death full of suspicious points, constricted pupils, pigmentation, the chemical smell in the house, the books on the bookshelf, the reagent bottles in the laboratory."

Yang Ping nodded: "Then do you think there's a connection between these things?"

Zaxi hesitated for a moment: "Yes, but I don't know what the connection is."

Yang Ping said, "Then go and investigate. Investigate all the clinical manifestations of organophosphate poisoning, investigate cases of skin contact absorption of organophosphates, and investigate whether organophosphate compounds are related to pigmentation. Tell me your thoughts tomorrow morning. In fact, an excellent doctor's reasoning ability is no worse than that of a detective. The process of a doctor diagnosing difficult and complicated diseases is to connect fragmented symptoms, signs, test results, etc."

Zaxi took a deep breath: "Okay."

That evening, Zaxi reviewed all the information on organophosphate poisoning, listing out the clinical manifestations one by one: constricted pupils, salivation, sweating, muscle tremors, pulmonary edema, difficulty breathing, and altered consciousness. However, the deceased only had constricted pupils and no other symptoms.

He also looked up cases of organophosphate skin absorption. They do exist, but usually require a longer time or higher concentrations. Furthermore, the symptoms of poisoning from skin absorption are slower to appear and less typical than those from inhalation or ingestion; there may only be mild systemic symptoms or only localized manifestations.

Then he researched the relationship between organophosphates and pigmentation. After searching for a long time, he only found a very old article that mentioned a rare disease called "organophosphate-induced melanosis," in which people who have been exposed to organophosphate compounds for a long time may develop grayish-brown pigmentation on exposed areas such as their fingertips and face.

Zaxi stared at the screen, his heart racing.

He connected all the clues: long-term exposure to organophosphates, absorbed through the skin, led to chronic poisoning, causing pigmentation and weight loss, and then at some point, a single large dose of exposure caused acute poisoning, extreme pupil constriction, respiratory depression, and death.

But how did that "larger dose of exposure" occur? Was it the cup of tea? The book? Or something else entirely?
He recalled Yang Ping's words: "The books on his bookshelf are so well preserved."

What if those books weren't meant to be read? What if they were meant to be used for something else?

A thought suddenly flashed through Zaxi's mind, but it was too big for him to think about further.

He glanced at his watch; it was already past eleven at night. He remembered what Yang Ping had said: "Go to bed before eleven every day. That's an order." He hesitated for a moment, then closed his laptop.