Night blindness is a rare disease in the 21st century.

However, in ancient times, it was more common than among commoners because of the restrictions of living conditions. In addition to retinal lesions and congenital genetic diseases, the most important cause of this disease is vitamin A deficiency.

In other words, most people's night blindness can be solved by eating.

And when it comes to it, the things to eat are not particularly difficult, and things rich in vitamin A are relatively common, such as apples...... In ancient times, things called persistents, such as crucian carp and carrots, and animal livers, were not really valuable.

But what people are accustomed to in the future is also good in this year.

For example, the internal organs of animals, although the dignitaries do not like to eat them, and even regard them as lowly things, but that thing is not something that the poor can eat. Anyway, as far as Li Yuanjia knows, in this era that has been praised by many historians as "the rule of Zhenguan", many ordinary people can't even eat coarse grains all year round, what else can you expect?

Therefore, it is said that this disease is easy to treat, but it is very difficult to do!

Think about it, in the last few months of the twelfth year of Zhenguan alone, how many rebellions occurred in Datang? If the common people were well fed and warmly clothed, who would rebel with them?

But for Li Yuanjia, these are not things he has to worry about.

Then such an opportunity, he can come up with the treatment of night blindness and tell the people of Datang how to do it, as for whether they can do it and how to do it, that is Li Shimin's business. In the words of Xing Ye in "Wu Zhuangyuan Su Qi'er", it was not he who decided the size of the beggar gang, but the emperor......

The only thing Li Yuanjia has to worry about is how to come up with this method!

So he needed Han Lucheng to count the number of people with night blindness in the house and several Zhuangzi, and then use "a medical book he read" as an excuse to do an experiment on these people. Eat pork liver, lamb liver, chicken liver or something, carrots and crucian carp or something.

was afraid that he would forget about it after he went back, so Li Yuanjia explained to Han Lucheng in advance. And once these people in the family are cured, night blindness can also be recorded in the medical history of King Han......

After eating the hot breakfast in more than ten minutes, Han Lucheng and the others, who had been waiting next to him for a long time, immediately rushed up and began to give Li Yuanjia a set of clothes one by one.

Although he was very impatient in his heart, Li Yuanjia could only endure it at this time and honestly make a clothes rack.

The name of the State of Ceremonies is no joke.

In the future, there will always be some people on the Internet who say that the aristocracy needs to be substantial, and those old aristocrats in Europe are almost praised to the sky, one of the reasons includes their etiquette, clothing and castles, etc., but after coming to the Tang Dynasty, Li Yuanjia found that the ancestors did not know where the background was in this regard!

Don't talk about etiquette or anything, just a piece of clothing can give him a headache!

Let's not talk about what he likes or dislikes, anyway, there are more than a dozen kinds of prince's costumes included in the laws of the Tang Dynasty, each of which has strict regulations and is suitable for different occasions. For example, if you go to the mausoleum to worship the emperor today, you must not wear the wrong clothes, and there must be no stains, obvious wrinkles and other phenomena on the clothes, otherwise Li Yuanjia will wait to be played by the imperial historians!

Anyway, in this era, dereliction of honor is also one of the major crimes, and serious ones can be dismissed from office.

So when he put on layers of princely clothes, put on heavy hats, and put every part of his body in order, it was already after two pillars of incense. Shaking his somewhat heavy head, Li Yuanjia took a long breath and instructed Han Lucheng: "I'm afraid it will take a long time to go today, stew a pot of mutton soup in advance in the afternoon, and send some to Liang Guogong in the evening, so that they can go to the cold!" ”

"Yes, my lord."

"Oh, by the way, if someone comes to ask about the four-wheeled carriage, you just tell them to do it, but it will take a long time, and you can book what you want in advance!"

“…… Yes, I see. ”

……

Watching the king's carriage leave, Han Lucheng stood at the door for a moment, his eyes narrowed slightly.

Of course he understood what the king said just now.

Because just yesterday, two groups of people secretly found him in private and asked about the four-wheeled carriage. It's just that he didn't know what the king meant at that time, so he didn't dare to say more, and later reported the matter to the king.

Now listening to the meaning of the king's words, are you going to agree to them?

Subconsciously frowned, Han Lucheng couldn't understand the king's thoughts. The carriage is originally a big item, and it is more troublesome to do than to overturn or something, especially for a big man like Lu Guogong, where is the carriage so easy to make? Just the carved patterns and various details on it take a lot of work.

And the four-wheeled carriage itself is much more troublesome to make than a two-wheeled one.

There are only a few carpenters in the mansion such as Chen Mu who can make this thing, if there are really a lot of people who want it, won't they not want to do anything all year round?

"Do you mean ......?"

Suddenly thinking of a possibility, Han Lucheng's brows suddenly frowned: "Does the king want to build a workshop to build a four-wheeled carriage like the dumping workshop outside the city?" But...... In addition to houses and tools, such a workshop also requires a lot of manpower, and it costs a lot of money! Just to build a few carriages, is it worth it? ”

Thinking about it, Han Lucheng couldn't figure it out, and in the end he could only shake his head helplessly, and sighed secretly: "If that's the case, there will be more and more workshops outside the city, and those people don't know what to say when the time comes......"

……

"It shouldn't be too much trouble to build a carriage factory."

Listening to the creaking sound of the wheels of the carriage, Li Yuanjia secretly calculated: "There are definitely not many people who use it in the early days, and if you want to control the flowers, it is enough for two carpenters to take a few apprentices." However, if you want to build a four-wheeled carriage manufacturing line, it is not simply achievable, it requires a considerable investment of manpower, material and financial resources, at least to reach the ...... of the dumping workshop Third? ”

"No, a quarter, or even a fifth is enough!"

Lifting the thick curtain next to him, Li Yuanjia looked at the muddy ground outside, and then listened to the voices of countless people and horses around him, and the corners of his mouth couldn't help but show a wry smile: "For the sake of those magnates in Chang'an City, it is not worth building a carriage factory so big, only by solving the road problems outside Chang'an City, can four-wheeled carriages have the value of large-scale promotion in China......