It wasn't an apple that hit Newton.

"He's telling the truth."

Li Cheng first confirmed Arnold's statement, then said with considerable surprise, "You don't know? Haven't you seen a doctor?"

Reassured, Annie walked back from behind the sofa and said, "No, I've never been sick before, so I don't know what it feels like to be sick."

Li Cheng: "......"

This was the first time in his life he had ever met someone who had never been sick!

Upon hearing Anne's words, Arnold made the sign of the cross and smiled gently: "This young lady must be blessed by God."

The gesture of making the sign of the cross is perfectly normal, but on Arnold, it looks bizarre: a two-meter-tall, muscular man whose hands are often stained with blood, sitting on a sofa with a gentle smile, making the sign of the cross on his chest and muttering "God bless you..."

Regardless, Annie was quite pleased to hear that: "Haha, I think so too."

Whether God favors her or not, I don't know, but God must have overlooked her intelligence when He created her... Li Cheng's lips twitched, and he steered the conversation back on track: "Dr. Arnold, do you know why I invited you to come over?"

"I knew some of it beforehand."

After Arnold finished speaking, he looked at Li Cheng with a rather eager gaze that made Li Cheng's skin crawl: "Mr. Li, I am really excited to see you. Your ether is really useful. Can you imagine how shocked I was when I first saw the patient lying there like a piece of pork, quieter than those barbers, not making a sound, not even moving?"

What a strange metaphor for pork, and what the heck is this haircut? Are they not forgetting their old profession...? Li Cheng thought to himself, but said modestly, "It's nothing."

Arnold was originally a barber, but his exceptional skills caught the eye of Charles II, who appointed him as His Majesty's personal surgeon and dentist.

In early Europe, barbers were a fascinating profession. They not only cut hair, but also performed bloodletting, tooth extraction, amputation, and more. In short, they did what surgeons did, and they did what surgeons didn't do.

For example, in 1361, the Paris Barbers' Guild in France issued regulations, which were reiterated in 1383: "The Emperor's First Attendant Barber is in charge of the business of all barbers in the city of Paris" and is "the head of all barbers and surgeons in the country." In England, the guild of barbers in London, after separating from the religious order, was recognized by Edward IV in 1462, and in 1540, Henry VIII allowed certified barbers to join the Surgeons' Guild.

"No, this is by no means a small matter."

Former barber Arnold looked quite serious: "This can save more patients, which is a very important thing. Your achievements will be remembered forever."

Being praised so directly, Li Cheng couldn't take it anymore: "Wait a minute, Dr. Arnold, I didn't invite you here today to flatter me, but to discuss something important—I heard you're planning to use ether as an aid in the King's tooth extraction, right?"

"Yes."

Arnold answered frankly, “His Majesty has been troubled by his cavities, and I have offered to have them removed many times, but His Majesty has hesitated to agree due to the severe pain of tooth extraction—but after witnessing the miraculous effects of ether, His Majesty changed his mind.”

"That's right, that's why I came to discuss this matter with you today."

Li Cheng paused for two seconds, then said, "I've been researching things related to surgery lately. Originally, it would have been a while before I brought it out, but to prevent any accidents during the tooth extraction, I thought I'd mention it to you."

"First is ether. This stuff is somewhat dangerous, but you just need to make sure His Majesty tests it before the actual tooth extraction and don't use too much."

"Secondly, there's disinfection—I know you have people rinse their mouths with wine before extractions, but that's not enough. You also need to disinfect the extraction instruments with wine."

As Li Cheng spoke, he took out several bottles of prepared ethanol: "I have some medical alcohol of about 75 degrees that has a better disinfection effect. You can use it—it doesn't matter if you don't know what it is, just think of it as high-concentration liquor. If you don't believe me, you can try a drop and it won't be a problem."

The alcohol works best when it is between 70 and 75 degrees, but since there is no way to measure the alcohol content, Li Cheng used a clumsy method: first, he repeatedly distilled the alcohol to obtain 95 degrees, and then estimated and diluted it to about 70 degrees.

As for the technology of distillation, it was invented by the ancient Celts, the inhabitants of Ireland and Scotland, as early as before the Common Era, and was nothing new. For a long time, distillation was considered a reliable method for seeking wealth and immortality. Distilled spirits, known as the "water of life," were also used as medicine.

After doing all this, Li Cheng finally spoke, "The reason I did this is because, through research, I've determined that there are many tiny organisms in the air. If they accumulate on the extraction instruments, they can burrow into the wound and cause infection. Alcohol can kill them. So you must clean your instruments with alcohol before extraction, otherwise infection is very easy to occur."

From very early times, people have suspected that epidemic diseases and their occurrence are related to certain "small animals" or organisms. For example, in the 1st century AD, Marcus Terentius Varo wrote: "There may be unseen small animals in the swamps that invade the human body through their mouths or noses, thus causing serious diseases."

In his 17th-century work, *Experiments in the Development of Insects*, Francesco Reddy demonstrated that sealing cans of meat prevented spoilage and proved that the maggots parasitizing carrion were produced by fly eggs. Subsequently, mold on jams or other food surfaces was shown to originate from airborne "small animals." It was also noted that cotton wadding and gauze not only effectively removed dust and sand but also prevented the invasion of these "small animals."

Not to mention Hooke's "Micrographia" in 1665, which can be entirely attributed to that cell diagram, thus deducing that there are countless tiny organisms in the air, or microorganisms for short.

Such a logically rigorous deduction process is thus successfully formed. Although it is a process of reversing cause from effect, it makes the hypothesis seem less unfounded.

As for alcohol disinfection, it was discovered by Persian medical scientists in the Middle Ages; Li Cheng simply provided a method that was even more effective.

Arnold listened patiently to Li Cheng's suggestions, and out of respect for the inventor of ether, the recommender of Veronique, and the scholar, he decided to agree.

"I understand."

He looked at Li Cheng and said, "I will follow your advice and disinfect the tooth with alcohol before the extraction, and have His Majesty try it out beforehand."

The burly doctor was surprisingly easy to talk to, which surprised Li Cheng—he had thought the other party would have some professional dignity or something, and that it would take a lot of talking to persuade him.

Annie had been listening in a daze since earlier, and now she asked in bewilderment, "I didn't understand anything..."

"Can't you at least live up to your status as a college student?"

Li Cheng couldn't help but complain.

“What’s wrong with university students? Do they have to know this? Li Cheng, that’s prejudiced,” Annie said.

Arnold waited quietly for the two to finish speaking before saying, "Sir, if there's nothing else, please allow me to take my leave."

"Ahem, sorry."

Li Cheng quickly ignored Annie, who was always causing trouble: "Actually, there's another question I wanted to ask you—during the previous plague, you stayed in London, right?"

Upon hearing this question, Arnold's face showed a somber expression, and he made the sign of the cross on his chest: "It was a tragedy, and I was powerless to stop it. Fortunately, with God's blessing, we pulled through."

Li Cheng didn't want to ask about Arnold's feelings. He paused, and after Arnold finished expressing his emotions, he said, "Do you know that during the plague at that time, some people who died had rotten and blackened toes?"

After a moment of contemplation, Arnold shook his head: "I don't recall that. Although many patients have black spots all over their bodies, finger erosion... perhaps there are, but compared to those terrible black lumps and bleeding all over their bodies, there is really very little attention paid to the toes."

Thank you for your answer.

Having received the information he wanted, Li Cheng nodded to indicate that he understood. He did not try to persuade Arnold to stay any longer and instructed the butler to escort him away.

Chapter 139 Promoting Development

"Li Cheng, why are you suddenly asking about fingers? Is there something special about it?"

As soon as Arnold left, Anne, brimming with curiosity, began asking the questions Li Cheng had just asked.

Li Cheng was just about to get up and go for a stroll outside to soak up some sun when he heard the question and casually replied, "Do you remember your paper from the summer break?"

“I remember, it’s the one you wrote for me.” Annie wasn’t ashamed at all about hiring someone to write it for her. “The one I revised myself was discovered. I should have just asked you to write it.”

Li Cheng's lips twitched, too lazy to complain about the matter: "When I was reviewing the report, among a bunch of recorded information, there was a casual mention of several cases of deceased patients with 'abnormal erosion at the finger joints'."

“At first I didn’t pay much attention, but later when I was chatting with Mr. Stoller, we talked about one of his friends who had also died of the plague and whose fingers were ulcerated. So when I met the king’s doctor this time, I asked him about it to see if he remembered him.”

He blurted it all out in one breath, not because he wanted to discuss it with Annie, but simply... it just came out of his mouth. It was like talking to a pet, he couldn't be bothered to hide it at all.

"......Forehead"

After hearing this, Annie scratched her head and thought hard, then said, "Was this mentioned in that report? I don't remember it."

"..."

Li Cheng paused for two seconds, then reached out and patted Annie's head twice, saying earnestly, "Remember to use your brain a little when you eat."

"Go! Go! Go."

Annie, somewhat embarrassed and angry, slapped his wrist away: "You're just trying to insult me. What's so great about having a good memory? Don't you know you can't just touch someone's head?"

No, no, no, you've already transcended the human realm in my heart... Li Cheng thought to himself, but changed the subject, saying, "Okay, let's not talk about that. By the way, do you know where Newton is? I'm taking her out to get some sun."

He recently began to suspect that Newton's lack of height was related to his inactivity—that little guy stayed indoors all day, either calculating data, conducting experiments, or reading and writing notes. He hardly moved around, let alone basking in the sun. It would be a miracle if he grew taller.

So, thinking that he was still young and had a chance to work harder, Li Cheng decided to start focusing on Newton's growth and development now.

Just this morning, he had told Freya that he had to prepare a cup of hot milk for Newton every morning and evening, and he had to make sure she drank it... Freya agreed to this at the time, but for some reason, the way she looked at Li Cheng was a little subtle.

"I don't know, go find out for yourself."

While answering that she didn't know where Newton was, Annie shook her head, looking a bit like a dog shaking its fur after being petted: "Stop joking. I finally have a day off. Last time, Newton dragged me to sit there like an idiot all day. I can't waste today."

After saying that, Anne ran off in a flash. Just a couple of days ago, her caregiver ordered a batch of wooden plates, which Li Cheng guessed were some new cat training props. Speaking of which, Elizabeth, having suffered so much, recently started meowing and running away whenever she saw Anne.

Regarding why Annie wouldn't let go of the cat, Li Cheng, after careful deduction, judged that it was likely an internal fight between pets, just like the old dog bullying the owner's newly bought kitten... However, it's also possible that Annie was simply being silly and wanted to train the cat.

Lost in thought, Li Cheng headed toward the laboratory. Usually, when you want to find Newton but don't know where she is, going to the laboratory to try your luck is the most likely way.

Da da da—

Li Cheng was still wondering where to find Newton when he suddenly said... no, I mean, Newton, and Newton appeared.

A golden figure in a simple dress moved quickly through the corridor, her small head turning left and right, her eyes scanning the surroundings as if searching for something.

Upon seeing Li Cheng, her azure eyes lit up, and she swooped towards him like an eagle spotting its prey.

Why an eagle? If you think about it that way, you'll have a monkey, a cat, and a bird all at once! The monkey can do a front flip, the cat can carry a wooden plate, and the bird can do math problems—you could practically open a circus!

"You've come at the right time; I need your help with an experiment."

Newton stopped in front of Li Cheng, speaking as he reached out to grab Li Cheng, intending to lead him towards the laboratory.

Logically speaking, 16 years old is a time when people grow up very quickly. However, through simple visual estimation and comparison with reference objects, Li Cheng sadly discovered that since they met two months ago, Newton's height has not changed by 1cm and he can only barely reach Li Cheng's chin.

I have to take her out to get some sun... Li Cheng thought to himself as he steadied himself to prevent being pulled.

Newton was initially eager to take his assistant back to the lab, but after a couple of tugs, he found he couldn't budge them and turned around in confusion: "What's wrong? Are you busy right now?"

"Can the experiment be done later?"

Li Cheng pointed out the window with a serious expression: "The weather is nice now, put your experiment aside for now, come with me for a walk and get some sunshine."

The sun was shining brightly outside at this time. The warm sun was bright but not scorching, which allowed the body to synthesize vitamin D without feeling hot. The sunlight was just right and made people feel comfortable.

Facing the comforting sunlight, Newton glanced at it casually before looking away, and continued to tug at Li Cheng's sleeve: "What's so great about the sun? Since you have nothing to do, come and keep me company while I do experiments. I'm at a very crucial point here."

"No matter how crucial it is, it won't work."

Li Cheng shook his head.

Upon hearing his reply, Newton frowned deeply, looking quite displeased: "Are you sure you don't want to help?"

Miss Newton is quite terrifying when she gets angry; she will use her enchanted, powerful, piercing diamond-grade canines to bite people, and blood will always be drawn.

Seeing this, Li Cheng thought for a moment and decided that he couldn't be too forceful.

So he asked step by step, "Do I really need to help with this experiment?"

Newton listened and pondered for a moment: This experiment was originally an idea she came up with when she encountered that annoying red-haired little girl, and she only recently restarted it. Although she had collected quite a lot of physical data on the women she knew, there was still a lack of data on the men.

Although theoretically any man would be acceptable, and even the more the better, she had a strong aversion to data collection from anyone other than Li Cheng.

So Newton replied, "Only you are suitable."

"I didn't expect I to be so capable... cough cough..."

Li Cheng's mind wandered at first, then he quickly said, "Well then, since I have to help with this experiment, I'll finish it for you as soon as possible, and then you can come out and get some sun, how about that?"

"..."

Newton bit her lower lip; she didn't want to go outside in the sun, but she also wanted Li Cheng to come and help her.

"It's just sunbathing, a simple comparison to help with the experiment, right?"