I Became a Plague Doctor in a Romance Fantasy Novel

Discovery of Bacteria (4)

14. Discovery of Bacteria (4)

The class is not over yet.

Istina, and the other undergraduates were looking at me. Some looked more tired than before, and a few students were burning with curiosity or academic zeal.

“Look. The organ system is made up of organs, and organs are made up of tissues. So, what units make up tissues?”

Istina blinked her blank eyes again. Organ system, organs, tissues… So what?

“Istina. You graduated from college, didn’t you? Why don’t you know anything properly? Oliver. Answer.”

Biology, and one of its basic principles.

Structure and function are closely related.

The basic unit of life is the cell because the basic unit must be a structure that maintains life activities while being distinguished from the outside.

“Uh… I don’t really know.”

“Think logically. Life activities are ultimately about separating and controlling the inside from the outside. The basic unit of life must also be made up of a similar structure. A small room structure.”

That’s the cell.

I went back to the drawing of the person I had drawn earlier. Individual, organ system, organs, tissues. The last stage is the smallest unit of life activities.

– The cell.

Most of them had expressions that they didn’t understand. The cell theory is not just proven by observation. It’s a fact, and if you think about it, it’s also a logical conclusion.

“That’s it for today. If there are no questions, we’ll end the class here. See you next week.”

The class ended like that.

There were no questions. Some students had expressions full of questions, but going over the class time is troublesome for everyone. Ultimately, I’m tired. My mouth hurts from explaining too much.

I felt tired from talking, so it ended a bit quickly. But I said everything I wanted to say.

As soon as the class ended, Istina walked towards me. Holding a bunch of papers. She seemed to be writing something, but I don’t know what.

“The thing you said last time. I understand what you meant now! Well… there’s still proof left, but. We have a microscope, so it should be quick.”

Right.

The experiments to be conducted for the time being are simple.

Having found a way to make the culture medium, I will create the medium, grow the bacteria, stain the bacterial colonies, and observe them under the microscope. This should be done by today or tomorrow.

“Are you experimenting today as well?”

“Yes. I’ll show you how to use the culture dish.”

“Ah, I see.”

In modern times, ready-made nutrient solutions tailored to the type of bacteria to be grown were available. It’s a bit disappointing that this is not possible now.

What will grow in the culture medium made from soybeans? Probably something very common like Staphylococcus aureus or Streptococcus. The type of bacteria isn’t particularly important right now, though.

Laboratory.

I slowly poured the culture medium from the kettle with Istina. The starch-mixed soybean powder filled the bottom of the Petri dish like a film.

“Will this be enough?”

The culture medium solidified immediately on the culture dish. It was like a very thin layer of mung bean jelly.

I nodded, and Istina covered the Petri dish. Despite some process, nine culture dishes were prepared.

“What happens now?”

The bacteria need to be inoculated into the culture dishes.

The method is simple.

Using a sterilized tool, apply the solution containing the bacteria to the culture dish. The microorganisms settled on the culture dish will form colonies.

Colonies are visible to the naked eye. Specific colonies can be physically separated or moved for future research. The number of colonies grown on the culture dish can also be counted.

This method can also be used to indirectly assess the amount of bacteria in a specific solution.

Anyway. I lit an alcohol lamp and sterilized the tip of the needle with the flame. Let’s wait a bit until the culture dish and needle cool down.

Today’s research subject is a solution, just plain water that you dip your hand in and take out.

The needle moved over the petri dish.

“Inoculate the petri dish densely, making sure the needle’s path doesn’t overlap. If the paths overlap, the bacterial colonies might overlap too.”

“Ah, I see.”

“The goal is to form bacterial colonies on the petri dish. It might not work well, but something will probably grow.”

In fact, there are so many bacteria around. If bacteria don’t grow, fungi will. Istina scratched her head.

“Bacteria are too small to see, right? What difference does it make to grow them?”

“If you grow them in a controlled environment, bacteria form colonies. Colonies are clusters of bacteria, a few millimeters in size. Colonies are visible and manageable.”

If bacteria form colonies on the petri dish, you can stain them, put them under a microscope, or culture them for research.

“How do you know that, Professor?”

“Well, I’ve done it before.”

I handed the needle to Istina.

“Give it a try.”

Istina stared at the petri dish, and I checked the time. It’s 4 PM. How long does it take for bacteria to grow?

Staphylococcus aureus takes about 12 hours to form colonies. It’s 4 AM now, but there’s no day or night in academia.

I shook Istina, who had fallen asleep in the library. She seemed to have passed out while studying.

“Istina. Wake up.”

“S-save me… I’m sorry…”

Talking in her sleep.

“Time to grow some bacteria.”

“I don’t like that…”

You’re the one who chose to be a graduate student. Tough it out, Istina.

Istina fiddled with her hair, rubbing her eyes as she slowly got up. It seemed she finally grasped the situation.

“I’m sorry. Please pretend you didn’t hear that.”

“Okay.”

Istina avoided my gaze.

“Are the bacteria fully grown?”

“They should be by now.”

“Let’s go check… But, professor, couldn’t we have checked after sunrise?”

We arrived at the lab.

The cultivation was a success. The colonies that had grown successfully were barely visible. It seemed like there were less than ten on one plate. What’s the reason? Whatever the reason, Istina was impressed.

“Just as you said, professor. From the bacteria growth to the size of the colonies. We just need to move the colonies under the microscope.”

I nodded.

“Now we just need to look at them under the microscope.”

“This is just out of curiosity, but if we leave the bacterial colonies alone, will they keep growing?”

No, they won’t.

Bacterial colonies don’t have a system to transport nutrients or oxygen to their interiors. So, they can’t grow beyond a certain size.

“Once they reach a critical size, they can’t grow any larger. Nutrients can’t reach the center of the colony.”

Istina wrote something in her notebook.

“I’ll get the glass slide.”

I carefully picked up a single colony with tweezers and placed it on the glass slide. So far, so good. Now I needed to figure out how to fix the bacteria.

I dropped a single drop of distilled water onto the colony on the glass slide and passed the sample over an alcohol lamp to dry it.

The sample preparation was almost complete, and now all that was left was staining. Istina dropped the stain she had brought onto the sample.

Ah, I remembered.

Staphylococcus aureus grows best at human body temperature, around 36.5 degrees Celsius. Since we attempted to culture it at room temperature, the results were bound to be somewhat lacking.

Well, one colony should be enough.

Now we just had to wait a bit.

“I’m sleepy.”

“Take a nap later in the day.”

“What do bacteria look like?”

“They look boring. Usually spherical or rod-shaped. Sometimes they look strange, though.”

For example, the syphilis bacteria have a peculiar spiral shape. But we wouldn’t have the technology to see that. The microscope we’re using now is close to the minimum specification needed to see bacteria.

Let’s take a look.

I moved the sample under the microscope. Adjusted the focus, and… I was a bit worried, but it looks good. Round purple granules clustered together.

Even at a glance, it’s Staphylococcus aureus.

I can see why they call it “grape-like” cocci. They cluster together like grapes, and they usually turn purple when Gram-stained.

I took my eyes off the eyepiece of the microscope.

“Istina. Come here and take a look.”

Istina put her eye to the microscope.

“I can really see it… Is this a bacterium?”

“Yes.”

Istina sat back down, looking like a child who had just received a birthday present.

“This will open a new horizon for humanity. It might be the greatest discovery of this century.”

I understand the sentiment, but it’s too early to celebrate.

This is literally just the beginning. Hooke discovered the microscope, Gram discovered staining.

Lister’s discovery of the need for hygiene in clinical settings and Pasteur’s experiments proving that bacteria cause disease are still to come.

“Let’s write up the research results. The sooner we write the paper, the sooner we can present it.”

Istina nodded.

Right, I was going to see Professor Klaus, but I couldn’t go after class earlier.

Wouldn’t the conversation go more smoothly if we had visible results?

First, let’s organize the experiment details.