Thinking of this, Lin Feng's originally cold and hard expression suddenly softened. He looked at Qin Lan and Su Wanqing kneeling in the snow, pleading desperately, and he had already made up his mind.

"You two get up first." Lin Feng's voice remained calm, but Qin Lan and Su Wanqing keenly sensed a glimmer of hope.

The two quickly wiped away their tears and looked at Lin Feng with hopeful eyes.

"What's the specific situation with that girl named Tang Bao? Besides the high fever, are there any other symptoms?"

Lin Feng asked, his tone as if he were inquiring about something unrelated to himself.

Qin Lan quickly described Tang Bao's symptoms in detail: persistent high fever, incoherent speech, weakness, rapid breathing, and seemingly some coughing.

As Lin Feng listened, he quickly compared the symptoms with the medical knowledge he had just acquired in his mind.

She most likely has a severe bacterial infection, most likely sepsis caused by pneumonia or other respiratory infections.

In this situation, without antibiotics, the mortality rate is extremely high.

“I can try to save her,” Lin Feng finally said.

Upon hearing this, Qin Lan and Su Wanqing burst into tears of joy: "Thank you! Mr. Lin Feng! We will never forget your great kindness!"

Don't get too excited yet.

Lin Feng interrupted their gratitude, "I'm not entirely confident, and saving her requires some special 'medicines,' the production process of which is very complicated, and I'll need your help as well. If we fail in the end, don't blame me."

"No! No! We would be extremely grateful if you were willing to help!" Qin Lan said repeatedly.

Lin Feng nodded and said, "Wait here for me for a moment." After saying that, he turned around and walked into the storage room next door, which was also his "temporary laboratory".

Based on the knowledge that came to mind, the most readily available primitive antibiotic was undoubtedly penicillin.

The source of penicillin is certain specific Penicillium molds.

He recalled that some of the dried meat and sweet potato cakes he had stored had indeed developed some greenish mold spots due to the occasional damp storage environment.

He immediately started searching and soon found a small piece of moldy colony on a piece of sweet potato cake with slightly moldy edges. It was a typical bluish-green color with white fuzzy edges.

"This is it!" Lin Feng thought with delight.

Next came the preparation of the culture medium. His knowledge told him that he could use boiled sweet potatoes (rich in starch) as the base culture medium, with a small amount of sugar and some specific mineral salts added.

Next comes the inoculation and cultivation of mold. This requires a relatively sterile environment and a suitable temperature.

He can sterilize the earthenware pot with boiling water, then inoculate the selected Penicillium mold into the culture medium, and then place the earthenware pot deep in a cellar with a relatively constant temperature for cultivation.

This process sounds simple, but achieving "relative sterility" in such a primitive environment is almost an impossible task.

But Lin Feng had no choice but to do his best.

He took several clean earthenware jars, used a strong fire to roast the inside for initial disinfection, and then rinsed them repeatedly with boiling water.

Then, he mixed the mashed sweet potato with golden fox rice soup, added a little honey and some powder he scraped from a specific mineral, and made a simple culture medium.

He carefully used a thin iron wire that had been heated red-hot and then cooled to pick up the small patch of bluish-green mold, inoculated it into several earthenware jars containing culture medium, and then sealed the mouths of the jars with treated clean animal hides and beeswax.

Only after he had done all this did he leave the storage room.

"Come with me."

Lin Feng spoke to Qin Lan and Su Wanqing, and then led them to their cave.

At this moment, the atmosphere inside the cave was gloomy and desolate. Qian Xiaoxiao, Ruan Mengtian, and Shen Jiaqi surrounded Tang Bao, helpless, and could only watch her breath grow weaker and weaker.

Lin Feng's arrival was like a savior to them.

"Mr. Lin Feng!"

Lin Feng ignored their greetings and went straight to Tang Bao's side, bending down to check on her condition.

The pupils reacted sluggishly to light, breathing was rapid and weak, the skin was frighteningly hot, and there were some fine red rashes on the neck.

"The situation is terrible."

Lin Feng made a judgment. His knowledge told him that this was already a sign of a serious infection.

He turned to Qin Lan and said, "From now on, you must strictly follow my instructions. First, remove all the wet cloths from her body and wrap her in clean, dry animal hides to keep her body warm, but don't cover her up too tightly; let her dissipate heat."

"Yes!" Qin Lan quickly did as instructed.

"Secondly, boil a lot of water, the more the better. Then thoroughly wash all the pottery and wooden bowls you have used with the boiling water. From now on, all utensils used to feed her water or food must be scalded with boiling water."

Lin Feng continued, explaining that this was to minimize cross-infection.

Although the women did not understand the significance of doing so, they still began to act without hesitation.

Lin Feng then took out some herbs that he had previously collected and dried, which had the effects of clearing heat, detoxifying, and calming the nerves (these were also identified by him after his "knowledge emerged"). He had them brew them with boiling water, and after they cooled down a bit, he tried to feed some to Tang Bao.

Next, Lin Feng began directing the women to conduct preliminary cultivation of "antibiotics".

He instructed them to build a small, relatively enclosed cultivation greenhouse near his cabin, following his instructions—actually, it was just a shallow pit dug in a sheltered spot, with heated stones at the bottom to maintain the temperature, and covered with animal hides and branches.

Then, he carefully placed several ceramic jars inoculated with mold into this makeshift "incubator".

He told the women to always pay attention to maintaining the temperature here, not too high or too low, and to report to him every day.

The next few days were a long and agonizing wait for the women.

They took turns guarding the incubator, carefully controlling the heat, afraid of making any mistakes.

They kept a close eye on Tang Bao's condition. Although the herbal water Lin Feng gave her stabilized her high fever a little, there was still no obvious sign of improvement.

Lin Feng, on the other hand, devoted almost all his energy to the research and development of "antibiotics".

He checks the mold growth in those earthenware jars every day.

A few days later, when he saw a thick, bluish-green fungal carpet floating on the surface of the culture medium and emitting a distinctive musty smell, he knew that the first step had been a success!

The next step is the extraction and preliminary purification of penicillin. This is also a complex process.

Based on his knowledge, he needed to first adjust the pH of the culture medium to acidic, and then use some kind of organic solvent for extraction.

In this primitive environment, he could not find standard organic solvents, but he learned from his knowledge that the oils of certain plants or the alcohol produced by high fermentation could also play a certain role in extraction under specific conditions.

He then directed the women to collect a large quantity of a certain oily nut and extract the oil using primitive methods.

He also tried to ferment honey and wild fruits to a high degree, hoping to obtain a high concentration of alcohol.

Under his direction, the women, like a group of devout apprentices, conducted all sorts of "experiments" that they could not understand at all.

They watched as Lin Feng transformed the moldy liquid into another form through a series of mysterious processes—filtration, sedimentation, mixing, heating, and cooling—filling them with awe and bewilderment.

They didn't know what Lin Feng was doing, but they could sense that he was doing something very important, even "sacred."

After nearly a week of tireless effort, Lin Feng finally obtained a small bottle of pale yellow, slightly cloudy liquid with a peculiar odor from a pile of murky liquid, and he breathed a long sigh of relief.

This is the "crude penicillin solution" that he extracted using the most primitive method!

Although its purity and efficacy certainly cannot compare with modern industrial products, Lin Feng believed that it must contain effective ingredients that could save Tang Bao's life!