"Xiaoyou, do you really have a way?" Sun Simiao's face was excited, after all, it is better to have a method than nothing, whether it works or not, it is much better than sitting still.

"Well, there's an earthwork that prevents smallpox." Zhang Nan also looked solemn, nodded and said.

"Bastard, that's a recipe to prevent smallpox, how can it be called earth. Do you know that with this recipe, the people of my Datang can no longer be bothered by smallpox? Li Er interjected on the side.

Zhang Nan directly skipped Comrade Li Er's complaint and said: "The method is there, but there is a very important thing to use as a medicine primer." ”

"Oh? What is it, Qingquan, you just have to say, as long as this thing is within the border of my Datang Kingdom, then I will send someone to search for the entire Datang, and I will find it for you. Li Er nodded and made his assurance.

"It's not that serious, it just needs a cow." Zhang Nan said.

"Cow??" Li Er and Sun Simiao obviously didn't expect that Zhang Nan's medicine primer that could treat smallpox was actually such an ordinary livestock.

"Yes, and it has to be a sick cow, it must be a sick cow, and ordinary cattle are not good." Zhang Nan continued.

"Sick cow??" Li Er and Sun Simiao still couldn't understand Zhang Nan's medicine primer.

"This, Xiaoyou, Lao Dao has been walking the world for so many years, and he has seen many strange medicine primers, but what is the reason for this sick cow to be used as a medicine primer?" Sun Simiao asked with a humble look.

Seeing Sun Simiao's humble and studious appearance, Zhang Nan had to give Sun Simiao a rough explanation in easy-to-understand words.

"Dare to ask Sun Zhenren, why does Sun Zhenren think people get sick?" Zhang Nan didn't explain at first, but asked rhetorically.

"This ...... Lao Tao believes that people eat grains and grains, and it is inevitable to get sick, and there are thousands of reasons for this disease, but in the final analysis, it is caused by the wind and evil entering the body. Sun Simiao thought about it and gave an answer that he felt was reliable.

Zhang Nan is also very satisfied with this answer, not that Sun Simiao is right, but that Sun Simiao now has the concept of the virus, and with this concept, it is much easier to explain.

"What Sun Zhenren said is not bad at all, and this smallpox is also a kind of wind evil." Zhang Nan said.

"But what does this have to do with sick cows?" Li Er asked on the side.

"Don't worry, the emperor is in a hurry, the minister will say it now. People are infected because the wind evil enters the body, and cattle are infected because the wind evil enters the body, and cattle will get a disease very similar to the human smallpox, but this disease is not fatal to people. Zhang Nan said.

After hearing this, Sun Simiao frowned and said, "Does Xiaoyou want to use the disease of this sick cow to infect people?" ”

"That's right, that's what it means, because the sick of cattle don't die, but once a person has this disease, the human body will produce an antibody, and this antibody can't resist other diseases, but it can resist smallpox." Zhang Nan said.

"What does Xiaoyou do with this antibody? Why is it that this antibody is not infected with smallpox, and that this antibody only resists one disease, smallpox? Sun Simiao obviously couldn't understand the concept of this antibody proposed by Zhang Nan very well.

"How do you explain this to Sun Daochang? It's troublesome to explain this, so it's better for us to treat the people first, and then I'll talk to Sun Zhenren in detail when the daypox passes. Zhang Nan said.

"Okay, let's go find the sick cow now." Seeing that Zhang Nan agreed to go with him to treat the patient, Sun Simiao was happy.

"There's no need to be so troublesome, I asked Liu Bing to go to the palace to have a look, and by the way, I went to a few big villages near Chang'an City to ask, there must be one." Li Er said confidently.

Li Er dares to say this, or thanks to the law of the Tang Dynasty, the law of the Tang Dynasty stipulates that private individuals are strictly forbidden to slaughter and plough cattle, and every cow must go to the government to report, because the cow is the main labor force, and even if the cow dies, the owner of the cow must go to the government to report, and explain clearly how the cow died, if it is a normal death, then it can be eaten or peeled and sold for meat, so almost every cow in the Tang Dynasty is recorded in the local government, and the cattle are more expensive than people.

"Then the emperor will be troubled." Sun Simiao thanked Li Er.

"Don't bother, as the emperor, I naturally want to run around for the people of my Tang Dynasty, which is what I should do. As long as this sick cow can really defend my Datang against smallpox, then I will build a temple for this cow outside this Chang'an City, and let the people of my Datang go day and night to worship this cow that has contributed to my Datang. Li Er smiled modestly. But there is a look on my face that you are coming to pat me on the back.

When Zhang Nan heard this, he immediately complained secretly in his heart, this sick cow also built a temple, what is this temple called? Sick cow temple?

Of course, Zhang Nan didn't go along with Li Er's wishes, so Li Chengqian complied with Li Er's wishes and slapped Li Er's sycophants. Li Er listened and nodded again and again, as if in the clouds.

"By the way, the emperor, you can take this protective suit back to the palace, just in case." Zhang Nan suddenly remembered that he didn't need protective clothing at all, because he had been vaccinated against cowpox, so he would not be infected with smallpox virus.

"Well, I have that intention, too." Li Er nodded and said.

"As for me." Zhang Nan said, then took off the protective clothing on his body and handed it to Sun Simiao.

"Let's let Sun Zhenren wear it to the village where smallpox broke out." Zhang Nan said with a smile.

"Xiaoyou, I can't help it, this is the clothes you used to prevent smallpox, how can you give it to Lao Dao?" Sun Simiao was a little embarrassed when he saw Zhang Nan being so generous.

"Yes, Qingquan, you should wear these clothes, it's better for me to give my body to Sun Zhenren, anyway, there shouldn't be smallpox in the palace." After Li Er thought about it for a while, he decided to give his body to Sun Simiao.

"No, no, no, Your Majesty, this can't be helped." Sun Simiao was even more honestly frightened. Sun Simiao, who originally took Zhang Nan, was uneasy in his heart, if he took Li Er, Sun Simiao would be uneasy and afraid.

"Okay, the emperor, just keep it, just let Sun Zhenren wear mine, I won't get smallpox anyway." Zhang Nan said with a smile.

"Oh? Why is Qingquan so sure? Li Er's face was strange.

"The emperor thinks that how the minister learned about the method of preventing smallpox in this sick cow is entirely because the minister has already done this experiment." Zhang Nan said.

"Oh? Xiaoyou has already tried? It seems that this method can be used directly without trying again, and Lao Dao still thinks that this will find a sick cow and try it on his own body first. Sun Simiao said.

"There's no need to be so troublesome, when the time comes, as long as Sun Zhenren takes a knife and dips it in the sick liquid of this cow and stabs everyone, it will benefit all the people." Zhang Nan said with a smile.