Datang: The prince of salted fish was overheard by Li Er

Coming out of the imperial study, Li You muttered to himself while chewing the compressed military rations in his hand: "With Li Jing's situation today, it seems that the medical examination center of the medical school has to be opened."

"The medical school has been established for so long, it's time to find some opportunities for these students to practice their skills!"

At this time Li Jing was walking behind him, and asked a little puzzled: "What does the physical examination that King Yan said mean?"

Li You glanced back and said: "Actually, it's easy to understand, it means literally, a physical examination is to check the body."

"Let the doctor check it regularly, so that the disease can be detected earlier and treated early."

Although people in this era don't shy away from diseases and avoid medical treatment, they generally don't take the initiative to seek medical advice when they are not serious.

This has also caused many diseases to miss the best treatment time when they are discovered, so that small lesions become serious diseases, or even incurable diseases.

Just like Du Yan before, the calculus was originally a small problem, which might be solved by taking medicine, but because he didn't seek medical treatment, the whole liver developed lesions and eventually passed away.

After that, Li You began to prepare for the medical examination center.

Although there is a lack of modern testing methods, Li You believes that many problems can still be found by relying on the observation, hearing, questioning and some basic tests of Chinese medicine.

Seeing that Li Jing was interested, Li You invited him: "I heard that Wei Guogong has not been very comfortable since he came back from Turkic. Why don't you invite you to be the first person to experience this medical examination center?"

Facing Li You's gracious invitation, Li Jing was also taken aback for a moment, then nodded.

"The body is not as good as it used to be when I get older, go for a physical examination, and let Dr. Sun take a look at it."

"Recently, not only my waist and legs are sore, but my eyesight is not as good as before. Sometimes when I read and write, I can't see the nearby things clearly."

The Li family of Longyou claimed to be the descendant of Li Guang, the parachutist of the Western Han Dynasty. He was good at riding and shooting since he was a child. Now that he is getting older, his eyesight is not as good as before, which made Li Jing feel a lot of emotion.

Li You is quite clear about Li Jing's blurred vision due to getting older.

According to modern terms, this is called presbyopia.

Presbyopia, that is, presbyopia, is a physiological phenomenon, not a pathological state, nor a refractive error. It is a visual problem that will inevitably occur after people enter middle age.It is one of the signs that the body begins to age.

The occurrence and development of presbyopia are directly related to age, and most of them appear after the age of 45. Li Jing is in his 50s, and aging is also a normal phenomenon.

Li You rolled his eyes and said, "This is easy to handle. Duke Wei should find some time to come to the Medical Examination Center of Shence Mansion. This king will definitely help you solve this problem."

For aging, optometry is a reliable and effective method.

Compared with the concave lens of myopia, the polishing of the convex lens of reading glasses is relatively simple.

Besides, even if a good optometry cannot be done, it is still possible to make a magnifying glass for Li Jing.

Now that the manufacturing technology of the glass workshop is relatively mature, Li You feels that it is time to start polishing various lenses.

Don't look at the simplicity of convex and concave lenses, but they are very useful.

Whether it is glasses that are closely related to daily life or telescopes used in the military, it is a technological revolution in this era.

In China, although the book "Mozi" in the Warring States Period described the law of lens imaging, the lenses at that time were all made of gemstones and amber. Not only did they have poor light transmission, they were also too expensive, and their applications were very limited. .

Thinking of this, Li You smiled mysteriously again: "At that time, this king will not only heal Duke Wei's eyes, but also give you another weapon on the battlefield. Duke Wei must come."

After speaking, before Li Jing could react, Li You quickly left.

Glasses and binoculars are a big business. If this matter starts with Li Jing, then it will be a very good starting point.

However, Li You still doesn't know how the lens grinding technology is now. He needs time and Haig to study it.

Li You walked into Haig's small courtyard with excitement, pushed the door open, but felt an inexplicable sense of crisis.

A smell of rotten eggs came, and Li You subconsciously covered his nose.

Then there was a "Zi Zi" sound in Li You's ear.

Immediately, he remembered something, and then he didn't care what the purpose of coming here was, he quickly took a step back, and then closed the door forcefully.

"boom!"

Just as Li You closed the door, a loud noise appeared next to Li You's ears, making him dizzy for a while.

It took a while for Li You to wake up. As soon as he opened the door, he cursed: "Haiger, can you lock the door before you study this thing!"

However, it was Haig's innocent face that greeted Li You: "My lord, I locked the outer courtyard!"

At this moment, Li You also had black lines on his face.

Since many of Haig's researches are classified, in order to ensure safety, Haig's yard is divided into an inner courtyard and an outer courtyard.

And just now Li You entered the outer courtyard through the door he opened.

For such a result, Li You can't get angry anymore, anyway, he is fine, at worst, he just needs to be more careful next time.

Then Li You became interested in what Haig had just studied.

"What were you doing just now? Why did you suddenly think of using gunpowder?"

Before asking, Li You thought about Haig's recent research direction.

It was found that neither the new generation of military rations on Fairy Bei's side nor the construction of the city and roads in Xinzhou in the north used this kind of thing.

Haig touched his head, hehe smiled and said, "It's not that kid Cui Wenju who comes to me every day to ask me to give it a try first."

"He said that using this thing, whether it is road construction or mining, will be much faster..."

"I only used a little bit just now, I didn't expect such a loud sound."

Haig was still explaining, but Li You squatted down to look at the explosive just now.

Judging from the power of the explosion, this is just a large firecracker.

But Li You was very surprised by this result.

Because what Cui Wenju brought out is black powder, one of the four great inventions of China in the future.

Black gunpowder has a long history in China, and it is said that it is a formula gradually researched by Taoist priests in the process of alchemy.

Although this is something that will inevitably appear in history, Li You is still extremely excited at this moment.

However, according to modern archaeological discoveries, the official appearance of black gunpowder was in the late Tang Dynasty, which is more than 200 years away from the current Zhenguan two years.

In other words, this kid named Cui Wenju accomplished this feat 200 years ahead of history.

But soon, he also wanted to understand.

The official large-scale use of gunpowder was in the late Tang Dynasty, but this did not prevent someone from discovering this miraculous phenomenon before that.

Alchemist alchemy is something that has been handed down since the Warring States period. This Cui Wenju was born in the Cui family of Qinghe. Maybe there is an alchemist in his family. It is not impossible to know from the alchemist.

Thinking of this, Li You suddenly said seriously: "Go and tell Cui Wenju that the gunpowder matter must be kept secret."

"You have also seen the movement just now. If this force is not controlled, it will have a serious impact."

"Take Jin Yiwei with you. If that kid still wants to resist, just take him down!"