CHAPTER 72: CHAPTER 67: MAINTENANCE

"..."

Yan Yundang glared, wide-eyed, at the composed Li Ang, then suddenly burst into laughter. "Interesting. Are you a Doctor?"

The nearby housekeeper, startled when Li Ang donned the wolf-hair mustache, feared Li Ang might say something to upset Yan Yundang. He quickly interjected, "Young Master Li Ang is an examination candidate at the Academic Palace this year. He ranked second in the preliminary test and achieved Upper Class A in the Imperial Examination, Mathematics, Painting, and the Herbal Medicine Department."

"Oh?"

Both Yan father and son raised their eyebrows simultaneously. Yan Yundang gave Li Ang a once-over and said gravely, "The Herbal Medicine Department is one thing, but with your build, you also scored Upper Class A in the Imperial Examination? Is the Military Mansion of Yu Country out of men?"

"Heh heh."

Li Ang smiled faintly. "The Imperial Examination values the unity of horse and rider. I achieved Upper Class A together with Red Horse."

"Hmm..."

Yan Lin pondered. Long-term horse riding inevitably left marks on one’s palms and legs. At a glance, Li Ang didn’t seem capable of triumphing over those Hu Ren youths who had grown up on horseback. However, the examinations at the Academic Palace were always fair and open, leaving him no choice but to believe it.

"Father, why don’t we... let him try?"

"..."

Yan Yundang glanced sideways at his son. He had been about to scold him again but softened at the sight of the worried look on his eldest son’s no-longer-young face. He heaved a long sigh. "Alright, alright. Well, let’s give it a try then."

Yan Yundang sat imposingly in his chair, his left palm spread open on the table, waiting for his pulse to be taken.

Not standing on ceremony, Li Ang adjusted the wolf-hair mustache above his lip and stepped forward. He first took the pulse for a while, then asked the family a few questions, and finally performed a physical examination of the upper abdomen and other areas.

There are many potential causes of jaundice, but the absence of fever, upper abdominal pain, or gastrointestinal bleeding rules out viral hepatitis, cholangitis, liver cancer, periampullary carcinoma, and other such diseases. Patients with liver cirrhosis would exhibit signs of chronic liver disease, spider nevi, liver palms, and dilated facial capillaries—none of which are present, proving it’s not that. Also, it’s not cholestatic jaundice—there are no xanthomas on the eyelids or similar areas, and according to the family, the patient’s urine hasn’t turned the color of dark tea...

Li Ang swiftly filtered through potential causes, then suddenly asked, "Duke, in recent times, how many hours a day do you sleep?"

Yan Yundang’s eyes twitched, and the corners of his mouth drooped.

Yan Lin took a deep breath. "Father has been sleeping six hours a day recently, sometimes even seven."

Excessive sleepiness...

Li Ang frowned slightly and asked, "Do you feel unsteady on your feet, find it difficult to walk, or experience frequent, symmetrical numbness in your hands and feet?"

Before Yan Yundang could reply, Yan Lin quickly interjected, "Yes."

"I understand."

After a moment’s thought, Li Ang slowly stated, "Duke, you have anemia."

"To be precise, it’s megaloblastic anemia."

Megaloblastic anemia is a type of anemia caused by impaired DNA synthesis and can be broadly divided into two types: one is pernicious anemia, resulting from vitamin B12 deficiency, and the other is megaloblastic anemia due to folate (vitamin B9) deficiency. These two types share similar clinical manifestations: fatigue, shortness of breath, dizziness, palpitations, a pale complexion or mild jaundice, often accompanied by abdominal distension, diarrhea, glossitis, and neurological symptoms such as weakness in the limbs.

"Anemia..."

Yan Lin’s face showed a complex expression as he said gravely, "Recently, my father has been taking Four Substances Soup and other blood-nourishing remedies, but there has been no improvement."

Li Ang shook his head helplessly. "Anemia, while a condition in itself, is also a symptom. The root cause lies in the gastrointestinal system."

"The gastrointestinal system?"

Upon hearing this, not only was Yan Lin shocked, but Yan Yundang and Qiu Jing also frowned.

"That’s right."

Li Ang nodded, then changed the subject. "When I walked through the rear courtyard earlier, did I see four cages of pigeons?"

Pigeons? Yan Lin and the others grew even more bewildered, completely unable to follow Li Ang’s train of thought. What do pigeons have to do with the gastrointestinal system? Are they supposed to be cooked into a soup?

Yan Lin nodded. "Yes, my son keeps those pigeons for fun. He started after reading an Academic Palace journal article about using pigeons for messaging."

"When I was a child, I also liked raising pigeons," Li Ang continued. "But because my family wasn’t wealthy, we couldn’t raise as many as the Duke Mansion—only ten. Of those ten, five had full plumage and gentle natures, while the other five were ill-tempered and often pecked people."

Yan Lin and the others frowned, unsure of the point of Li Ang’s story. Was he merely trying to say that five of them were no good?

Li Ang continued, "I liked the five gentle pigeons, so I fed them polished rice—finely ground to remove the bran and husk. The five ill-tempered ones I disliked, so I fed them cheaper, unpolished rice. However, over time, the five gentle pigeons that ate polished rice daily became lethargic, while those that ate unpolished rice remained as robust as ever."

"The controlled experiment method?"

Qiu Jing’s eyes lit up. Ever since hearing Li Ang explain this novel concept at the restaurant, he felt many things had become much clearer. Two control groups, differing in only one condition, with all other initial conditions identical. If their final results differ, then that initial differing condition must be the decisive factor causing the variance.

"That’s right. At the time, I wondered why the two groups of pigeons showed different results," Li Ang said. "I separated the five gentle pigeons: three continued to be fed polished rice, while the other two were switched to unpolished rice. Of the five ill-tempered pigeons, three continued with unpolished rice, and the other two were switched to polished rice. As time passed, I found that regardless of temperament, any pigeon fed exclusively polished rice became listless and ill. And all the sick pigeons recovered once they started eating unpolished rice again. Thus, I determined that unpolished rice contains a certain special substance. When pigeons lack this substance for a long period, they fall ill."

This was the experiment conducted by the Polish biochemist Casimir Funk in 1911. He coined a name for this special substance he had identified—’vitamine.’ Or, as we know it, ’vitamin.’