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control variable?

All the people present were elite scholars who had received preparatory education in the academy. They just frowned and thought for a while, and quickly understood Li Ang's general meaning.

"Is it mosquitoes, not evil spirits, that cause malaria?"

Song Shaoyuan and Zhai Yiming opened their eyes wide and muttered to themselves,

Ji Linglang was thoughtful,

Yang Yu looked at Li Ang curiously. Regardless of whether what he said was true or not, the theory that larvae mosquitoes cause malaria is a novel theory other than evil spirits, malaria ghosts, and disloyalty.

The servant standing at the door still maintained a reserved and respectful posture, without any movement.

Just a movement of his ears, as if he heard an order from the next room, he cupped his hands respectfully and asked, "So, Xiao Langjun, do you have any evidence?"

"Evidence, it can also be obtained by controlling variables."

Li Ang thought for a while and said: "If your master has leisure time, you can send someone to visit each square city to inquire about the terrain conditions of each square city, and summarize the number of residents in the square city who have suffered from malaria and died of malaria.

Residential area with high terrain, no water, no grass and few mosquitoes around.

Residential areas with high terrain, surrounded by water, grass and mosquitoes.

Residential areas with low terrain, no water, no grass and few mosquitoes around.

Residential areas with low terrain, surrounded by water, grass and mosquitoes.

As long as there are enough places to visit and the sample size is large enough,

It's easy to find out if and how malaria is related to waterweed mosquitoes. "

"this"

The servant frowned and said, "Isn't it too troublesome? There are 108 squares in Chang'an, with a population of 3 million."

"Your master asked, and I was just giving a suggestion."

Li Ang said casually: "There are ways to get the results faster.

When I visited Chang'an just now, I noticed that there are drainage ditches and small bridges on one or both sides of the streets in Chang'an.

These ditches are about one foot wide, and they are all open ditches exposed to the sun.

Coupled with the slow flow of water, mosquitoes can easily lay eggs in the ditch, hatch larvae, and produce more mosquitoes.

In order to prescribe the right medicine, a large area of ​​Fangshi must be selected first, and bluestone slabs shall be covered on the drainage ditch of the Fangshi, turning the open ditch into a dark ditch.

And in the dark ditch, a hollow wire baffle is set at intervals, between the baffle and the baffle, fork-tailed betta from Lingnan Road is cultivated.

There is no fork-tailed betta, and mosquito-eating fish such as herring are also fine.

Then ordered a ban on pedestrian fishing.

Thereby reducing the mosquito breeding caused by the drains.

Then distribute mosquito nets, mugwort and Artemisia annua to the residents.

Mosquito nets are hung in the bedrooms of adults and children, especially children under the age of five, while sleeping at night,

Mugwort and Artemisia annua are used to smoke and kill adult mosquitoes,

In addition, send people to eradicate low-lying pools and weeds that breed mosquitoes in the market.

After completing a whole set of procedures, and finally waiting for the malaria disease to appear in summer and autumn, we compared this square city with other square cities that did not set up underground ditches and did not kill mosquitoes.

See which Bianfang city has a lower rate of malaria.

The connection between malaria and mosquitoes is naturally known.

It is now June, and if we act now, we will see initial results in about three to four months. "

Li Ang talked calmly, "By the way, when summing up at the end, we must exclude the monks' residences in the market."

The servant asked in surprise, "Why?"

"Because the monk's breathing automatically drives away the mosquitoes flying around, and he rarely gets sick, so it can be regarded as a factor that will interfere with the results."

Li Ang said lightly, picked up the chopsticks again, and put another piece of vinegar celery for Chai Cuiqiao.

In fact, it's only half a month before the school exam, so it's really troublesome to find a high-end residence with a higher terrain in the north of Chang'an City.

But as a doctor, Li Ang, the more he understands the disease, the more he is in awe and fear of the disease.

Malaria is one of the diseases that killed the most people in the history of the other world. It can be said that the history of human beings is the history of malaria.

Some mosquitoes carry a single cell called Plasmodium. When the mosquito bites the human body, the Plasmodium enters the human body, infects the liver, produces thousands of new Plasmodium in the liver, and then begins to invade and infect the blood. Red blood cells further divide, multiply, and denature.

That's right, the merozoites transformed from Plasmodium will differentiate into male and female, and can survive in the human body for 60 days.

Once the male and female merozoites are re-inhaled by mosquitoes, they will reproduce in the mosquito body and form "gametes", and the gametes will become "kinetics", enter the mosquito's stomach wall to form oocysts, and finally pass asexual reproduction Become "sporozoites", actively enter the mosquito saliva, and start the next round of infection transmission.

The whole process is extremely cumbersome and complicated, and it can be called weird and exquisite.

For humans, the garbage released by the malaria parasite in the body will cause the body's immune response, resulting in alternating hot and cold, continuous sweating, and anemia, splenomegaly, and organ failure after repeated attacks.

'Even if calculated according to the most optimistic 1% malaria incidence rate, with a total population of 40 million people in Yu State, 4 million people suffer from malaria every year, and a large part of them are under five years old and have not developed sufficient immunity of children. '

Li Ang thought silently: "Without effective treatment, the mortality rate of falciparum malaria is as high as 40%.

And even if it is not malaria, mosquito bites may also transmit epidemic Japanese encephalitis, dengue fever, filariasis, and yellow fever.

Traders, livestock, and wild animals from all over the world may become the source of diseases. "

Before he became a monk and had basic disease resistance, Li Ang didn't want to test his resistance to infectious diseases at all.

Seeing what Li Ang said was orderly, the servant standing at the door became more respectful, cupped his hands and said: "My master said that if you are injured by cold in winter, you will have febrile disease in spring, you will be injured by heat in summer, and you will be sick with malaria in autumn.

Autumn is coming soon, there may not be so much time,

I would like to ask Xiao Langjun, is there a faster way to detect the relationship between malaria and mosquitoes. "

"Faster?"

Li Ang raised his eyebrows, thought for a while and said: "Then spend a lot of money, and ask monks who specialize in talisman Taoism to listen to the rain and patrol the clouds to write down the breeze talisman.

Distributed to local residents.

The Breeze Talisman can summon the breeze and repel mosquitoes, and it can also have the effect of preventing mosquitoes, but it is expensive-as far as I know, asking a monk in the cloud patrol to expend energy to write Zhang Talisman, no matter what, you have to start with nothing. "

The servant still maintained a respectful attitude, "Is there a faster way?"

"Um?"

Song Shaoyuan frowned and said, "Why is your master so aggressive?

We were just chatting privately, so it's fine if you knock on the door to interrupt,

Now my classmate has given two strategies, but you are still aggressive, isn't it a bit inappropriate? "

Although Song Shaoyuan has a loyal personality, he is not stupid.

The identity of the other party was unknown, and he rationally did not say Li Ang's name, only calling Li Ang a "classmate".

Zhai Yiming hesitated for a moment, and then chimed in.

Although he was usually a little jealous of Li Ang, no matter what, he was still a fellow student, and he couldn't watch his own people being bullied under the eyes of outsiders.

"."

Li Ang looked at the servant, his eyes quickly turned cold, and he said indifferently: "Since your master already knows the answer, why do you need to ask again?

I just want to remind one thing, people are doing it, and the sky is watching.

please come back. "

After finishing speaking, Li Ang flicked his sleeves and stopped looking at the servant.

And the other party bowed extremely respectfully to the end, then turned and left.

"Um?"

This time it was Song Shaoyuan's turn to be puzzled, and subconsciously asked Li Ang, "What do you mean by telling that servant that his master already knows the answer?"

"What else could it mean?"

Li Ang said indifferently: "I want to find out the connection between malaria and mosquitoes as quickly as possible, even before autumn comes and malaria breaks out in the city,

Then there's only one way."

"Direct proof."

Ji Linglang elegantly picked up a piece of vinegar celery, and added the next sentence for Li Ang, "Using the method of controlling variables, prove the relationship between malaria and mosquitoes."

————

In the next room, Qiu Jing, the medical officer of the Imperial Medical Office, looked at his friend across the table with an angry face, slapped the table and shouted: "Tantai Leshan!"

Siye, a schoolmaster named Tantai Leshan, sat on the spot, calmly accepting his friend's anger, "Why are you angry, Brother Qiu?"

On the wall of the box room, a piece of [Soundproofing Symbol] has been pasted, which can isolate the sound of the conversation between the two, so Qiu Jing didn't suppress his voice, and sternly shouted: "What the hell are you trying to do?!"