# Reassembly of Faith (4)
*
Germ theory.
In the history of the world I'd lived in, quite a few adventures preceded its acceptance.
The entrenched positions of humoral theory and miasma theory were simply too formidable, and anyone who championed germ theory was practically begging to be treated as a heretic.
Think of it as being treated the same way as someone who pushed heliocentrism in an age when geocentrism reigned supreme.
'People are creatures who can't believe something until they've seen it with their own eyes.'
The reason was simple.
Germs are invisible. Bodily fluids are not.
And yet, germ theory ultimately won its recognition the moment the microscope made them visible.
So on the day of the presentation, I simply arranged the microscopes across the stage and dove straight in.
"Good day, esteemed healers. I imagine seeing for yourself will be faster than any explanation I could give. These are germs I've cultured and stained over the past several months. If you have any questions during my presentation, please feel free to come up and verify for yourselves."
Scholars are creatures who are endlessly conservative about knowledge — and yet, the moment undeniable evidence shatters that conservatism, they go blind to everything else.
That was precisely why I'd prepared these microscopes.
"To begin, allow me to explain how I first came to discover these microorganisms."
I myself hadn't believed in the existence of gods until I witnessed divine power with my own eyes.
With miracles happening right in front of me, how could I deny them?
I was giving these healers the same thing.
There aren't many scholars who can deny what they've seen with their own eyes.
"Good heavens..."
"I've never seen such a clear microscope!"
"This can't be dust, can it?"
There was no need to explain how to use the microscopes.
Before germs, microscopes had already been used to observe capillaries, mold, parasites, and the like.
Any medical scholar worth their salt already knew how to operate one.
"Saint, are these germs naturally purple?"
"Germs are naturally translucent. I used a dye to make them easier to see."
I'd poured an enormous amount of manpower and capital into this step.
The process of finding the right dye was essentially pure manual labor, so I simply paid a group of low-rank healers to find it — and suitable dyes started popping up in no time.
This was probably why professors with more graduate students tended to produce more research output.
"These germs are moving. Their movement is unlike that of parasites, and they look nothing like dust — they must certainly be living organisms."
An aged healer's remark made me curl my lips beneath my mask.
That was exactly the reaction I'd been hoping for.
Ordinarily, germs don't move.
To be precise, they do move, but so torturously slowly that it barely registers as movement at all.
Which meant that if I showed just any germ, someone could easily argue it wasn't moving, and therefore wasn't a living thing — wasn't alive at all.
To head off that argument, I had deliberately cultivated the most motile species I could find.
'Good thing I went with Spirillum.'
Spirillum.
Among all germs, these were the most energetically mobile.
They moved as if announcing to anyone watching: I am a living organism.
And the trouble I'd gone through to cultivate them separately had been considerable.
Are you Spirillum?
Nope! Staphylococcus!
Are you Spirillum?
Sorry! Mold!
What about you?
Yes! I'm Spirillum, but the morning air is cold, so I'm about to die!
...Fuck.
The trouble I'd gone through to cultivate these alone.
I had nearly broken character and let my benevolent saint persona slip into outright rage.
Regardless, once the distinguished elders had verified the existence of germs with their own eyes to a satisfactory degree, I launched into the main explanation.
"Parasites are the smallest organisms we can confirm with the naked eye. However, my starting point was the idea that there might be something even smaller."
I tapped the first specimen with the short pointer in my hand.
"Please direct your attention here. This was collected from putrefied meat. The next specimen was taken from stagnant swamp water, and the one after that, from a festering wound on a corpse."
The existence of germs had been established.
But that didn't automatically translate into a causal relationship — that germs caused disease.
Could the process of germs triggering illness within the body be directly observed?
Unfortunately, no one in the 21st century had ever directly observed that process either.
Naturally, demonstrating it in this world was equally impossible.
So I changed my approach.
"Without exception, these germs were found wherever there was putrefaction."
Disease is invisible.
But fermentation and decay are not.
And the intuition that putrefaction is somehow linked to illness is not difficult to grasp.
That was why I chose putrefaction as my starting point.
"And not just in putrefaction — without exception, these same germs were found in the blood of patients who developed fevers after receiving Heal, and in infected wounds."
One in a hundred is coincidence.
Fifty in a hundred suggests some correlation.
A hundred in a hundred means clear causation.
And germs were found in over nine hundred out of a thousand sepsis patients.
Was there anyone who could argue against that?
"Furthermore, Rax — which many of you have begun using regularly — also serves as evidence for the existence of these germs. This chart compares the trends in febrile patients before and after each clinic began using Rax."
Rax.
A hygiene product everyone had simply started using under the assumption it might be a catalyst for divine power.
Clinics that used it saw dramatic reductions in febrile patients and a significant drop in divine power consumption.
"Our research confirmed that Rax causes germs to be annihilated. Which is to say: these germs may very well be the agents that obstruct divine power — the cause of disease."
Performing Heal with a sword still embedded is far more taxing on divine power than pulling the blade out first and then healing.
The principle that removing the cause reduces divine power consumption dramatically — that was common sense in divine magic.
And now, using Rax killed germs and reduced divine power consumption at the same time?
Then weren't germs the cause of disease all along?
That was my logic.
"And so I arrived at my conclusion. Rather than miasma — which cannot be seen at all — it is these germs: barely visible, yet undeniably present, that are the true cause of disease."
*
"...Based on this body of evidence, I propose the hypothesis that germs may be the cause of disease."
The presentation was over.
Leaving the conclusion as a "hypothesis" rather than a certainty was a deliberate choice to lower the psychological barrier to acceptance.
Germ theory had faced fierce resistance even in its original history.
So any method of lowering that resistance, however minor, was worth using.
"Are there any questions?"
And then, the moment I'd been most looking forward to — the Q&A session.
This was also the most crucial part.
How well I answered here would determine the fate of germ theory.
'Bring it on.'
I was confident.
How many times had I been torn apart by professors at academic conferences?
Compared to those people, the questions from this era were practically endearing.
The first to raise a hand was an aged elf healer seated in the front row.
"Yes, please go ahead."
"I am Erpen Adamberta."
A big shot right from the start.
Erpen Adamberta.
The elder of the Adamberta Sect, renowned for their secret arts in blood-based treatment.
That sect's divine magic specialized in blood regeneration.
An isekai hematology department, essentially.
And Erpen Adamberta was the living history of bloodletting — three hundred years of drawing blood from patients to heal them.
"Impressive statistics. I do not doubt that germs bear some relationship to disease. However, I find your logic somewhat thin as evidence that germs cause disease. Is it not possible that germs are a result of disease?"
A sharp question.
A classic problem in statistics.
For instance: heavy smokers are more likely to drink large amounts of coffee. And heavy smokers are more likely to develop lung cancer. Statistically, lung cancer patients tend to both smoke heavily and drink large amounts of coffee. But no one concludes that coffee causes lung cancer. The two are merely statistically correlated — not a cause and effect.
The elf healer had seen exactly that.
"I believe the matter can be explained through humoral theory. Our bodies carry four humors. When their balance is disrupted, disease follows. As that balance falters, the humors become contaminated and putrefaction sets in — as you described. And it is into that putrefaction that germs attach themselves, I would think."
"Much like maggots gathering on a rotting corpse."
"Precisely."
To summarize his argument:
Germs don't cause disease. Rather, as disease takes hold and the body begins to decay, germs attach themselves to it afterward.
It was a good question.
And exactly the question I'd been hoping for.
"I did conduct an experiment addressing that very point."
I had intentionally held this back during the presentation, saving it for the Q&A.
Why?
Because it was more dramatic that way.
Presenting everything upfront leaves no lasting impression.
Having a challenge raised and then delivering the rebuttal in the moment — that was how dramatization worked. That was how it stayed in people's memories.
I hadn't worried about the question not coming.
The people gathered in this hall today were the finest medical scholars of this age.
There was no way they'd let the session end on only superficial questions.
"Please, direct your attention here."
The pointer gestured to a curtain at the side of the stage.
The curtain rose slowly.
Behind it were two rabbits, each in a separate cage.
One was healthy.
The other was breathing in shallow, labored gasps, its flank visibly suppurating.
"This rabbit had a boil deliberately created on it. From that boil, I isolated a single species of germ and cultivated it in isolation for one month."
I held up a small glass vial.
"Inside this vial are those germs, and nothing else. No blood. No flesh. No marrow. None of that rabbit's bodily fluids whatsoever. Only germs."
The elders' gazes locked onto the vial.
"And I injected these germs into a separate, healthy rabbit."
The pointer indicated a second curtain.
As it rose, another rabbit was revealed — its flank suppurating in exactly the same way as the first.
"In the same location. The same shape of boil."
For reference, the germ in question was the anthrax bacillus.
The causative agent of anthrax — the most common disease among livestock.
"A single trial seemed insufficient for conviction, so I repeated the experiment over thirty times. Without exception, the same suppuration appeared every time. I do regret that practical constraints limited today's demonstration to a single rabbit — I hope you'll understand."
"..."
Erpen stroked his beard in silence as the explanation settled over him.
A moment later, a slow exhale escaped his lips.
"Hmm... Were you waiting for me?"
"..."
I said nothing.
But that seemed to be answer enough. Erpen Adamberta gave a single, deliberate nod.
"A splendid response."
"The honor is mine, Senior."
The elf healer returned to his seat with a look of quiet satisfaction.
He was regarded as a living legend even within this community of healers.
Three hundred years of walking a tightrope with bloodletting — that was genuinely remarkable.
And now that very person had stepped back, as though he had no choice but to accept germ theory.
The hall began to stir.
"Hmm... If Lord Erpen reacted like that..."
"It's fascinating, but isn't it still too dangerous to apply this immediately?"
"And yet to overturn centuries of established theory... things are working well enough as they are. Is there truly any need to change?"
The healers murmured among themselves, each forming their own impressions of germ theory and debating in clusters with their fellow sect members.
At that moment, a hand rose from the section where the Mencia Sect was seated.
'That person is...'
I recognized him from what Simeon had told me.
Archbishop Dormund Mencia.
Third-in-command of the Mencia Sect.
The man who had, more eagerly than anyone, moved to suppress my parents' legacy — who had worked harder than anyone to erase it.
Though that was only from Simeon's perspective.
What kind of person Dormund actually was, I didn't yet know.
'His first question will shape the first impression.'
"Please, go ahead."
"I am Dormund Mencia."
Dormund slowly folded his hands together and stepped forward toward the stage.
He studied me with what appeared to be a look of genuine concern.
"I have been deeply moved by the new insights you have shared with us today, Saint. Truly. I find myself unable to do anything but marvel at how the gods could have sent such a brilliant junior scholar to us."
His manner of speaking, at least, was exceedingly courteous.
Different from how Simeon had described him.
"However, there is one matter that leaves me confused. I humbly ask that you forgive this old man his ignorance and offer me some guidance."
"Of course."
Dormund smiled gently.
"I believe it was you, Saint, who once stated quite clearly that malaria spreads through 'contaminated blood.'"
That was true.
At the time, I had no way of explaining parasites or germs.
And my social standing had been nonexistent.
I wasn't even Director Schun back then — I had been an anonymous crow-masked physician who couldn't even use divine power.
In that state, suddenly declaring that germs existed, that parasites smaller than cells were causing disease?
One careless misstep and I might have been spending quality time with a heresy inquisitor.
Just like an astronomer proposing heliocentrism in the era of the geocentric theory.
So I had explained malaria's cause within the framework of humoral theory — attributing it to the problem of contaminated blood.
Mosquitoes drew contaminated blood and carried malaria from person to person.
At the time, the academic community had praised me endlessly for the brilliance of the idea.
And now Archbishop Dormund was pulling that past out.
"Mosquitoes draw blood from patients, then transfer that contaminated blood to others. That was the principle by which malaria spreads through an entire village, you said. Thanks to that discovery, quarantine measures in the southern regions were strengthened, and countless lives were saved — or so I've heard. And yet, Saint — are you now proposing to overturn that theory?"
The logic of his argument was clear enough.
Then what about your past?
Can you really deny what you yourself established?
'Hmm...'
People are, by nature, creatures who struggle to abandon what they've built and learned.
Everything accumulated over a lifetime — to be told it must be torn down.
How many people could accept that without hesitation?
The archbishop had clearly aimed for exactly that.
He was asking: can you deny your own past?
Any ordinary healer might have been quite flustered at this point.
But there was one thing he didn't know.
"Yes. I was wrong."
My past meant nothing to me.
I had already known about germ theory when I published the malaria paper.
I had simply found it too much trouble to prove at the time, and had postponed it for later — that was all.
And one more thing.
I was still in my twenties.
There was more ahead to accomplish than behind.
A mere ten years?
I could write it off as wasted effort and move on without a second thought.
This was only the beginning.
"At that time, I was operating on incorrect knowledge."
My calm admission seemed to catch Archbishop Dormund off guard.
"How can you be so certain of that?"
"Because unlike the rest of you, I have had to pay the harshest price every single time I was wrong."
"...?"
Dormund tilted his head.
Behind my mask, I slowly closed my eyes.
And with a quiet inward apology for trading falsely in the deaths of real people, I continued.
"When I began practicing in the Limbus Pit, I treated patients based on humoral theory. But having started from the wrong foundation, I lost many people I shouldn't have."
In reality, it was different.
There had been patients I couldn't save in those early Limbus Pit days.
But it was not because I had treated them using humoral theory.
The limitations of hygiene supplies, the limitations of antibiotics, the limitations of surgical equipment and facilities.
For all those reasons, there were patients I could not save even when I should have been able to.
And now I was falsely packaging their deaths as the product of my own ignorance.
With the excuse that this tragedy must never be repeated.
"Unlike you, I have no power to perform miracles."
Unlike these people, I had no margin for error.
A poorly sutured blood vessel and the patient died.
There was no drawing blood and then replenishing it with divine power.
Prescribing the wrong drug after a wrong diagnosis — there was no second chance.
They could recover from their mistakes with divine magic.
Mine led directly to failure and tragedy.
Whether that was a privilege or a curse, I wasn't sure.
But perhaps that was precisely why only I could have discovered germ theory in this world.
Because failure came to me in its most raw and unfiltered form.
"For the rest of you — for my seniors — there is always some way to bring a febrile patient back from the brink. But for my patients, when a fever came, it was over."
And so everything I could do until now had amounted to obsessively managing hygiene.
In a world without antibiotics, sepsis meant death.
All I had was washing my hands with carbolic acid until they cracked and drenching everything in alcohol until it seemed excessive.
Even then, roughly one in thirty patients would develop a fever.
When that happened, I would sit with the sense of powerlessness and turn to the healers for help.
"To you, fever is something to be overcome with divine magic. To me, it felt like an inevitable death. That is why I can say, in this particular domain, I have more at stake than any of you."
I met Archbishop Dormund's gaze.
"You asked whether my past was wrong. Yes. I was wrong at the time. Malaria is transmitted not through bodily fluids, but through germs — or parasites. Whether the cause is a germ or a parasite will need to be researched from the beginning again."
Dormund's eyes went wide.
He had apparently not anticipated that I would deny myself this thoroughly.
"Does that answer your question?"
"...I... understand."
Archbishop Dormund returned to his seat with an expression of someone who wasn't quite satisfied.
I turned back to the audience.
The lively atmosphere from just moments ago had gone quiet and solemn.
That wasn't the mood I wanted.
"I will continue taking questions."
The somber moment ended there.
I readied myself for the defensive battle ahead.
'Come on. Bring it on.'
Today, I needed to go all the way — to make germ theory the accepted theory.
So I would leave no room for dissent. Every question raised here would be answered in full before this was over.
'I need to develop antibiotics soon. And a form of divine magic that treats germ-based infections.'
Every day that passed mattered.
Because people who could have been saved must not go on dying needlessly.
***
The presentation was over.
Parting the quietly murmuring crowd, Erpen Adamberta made his way out through the rear of the hall and into the corridor behind it, his party following close behind.
The corridor held the cold air of a late autumn night.
Three disciples, unable to match their teacher's pace, hurried after him in quick steps.
"Teacher."
The foremost of them, a middle-aged disciple, spoke carefully.
"...What do you intend to do?"
Erpen did not slow his stride, but cast a sidelong glance with those blue eyes.
"About what?"
"About germ theory. Archbishop Dormund clearly pointed out a contradiction today, and besides — you've spent the last three months preparing something specifically for this, haven't you?"
Another disciple chimed in.
"If you were to present at an academic gathering soon, this hypothesis could be sufficiently put to rest..."
At the far end of the corridor, a coachman stood holding open the door of a carriage, waiting for them.
Before boarding, Erpen paused and looked up at the grey sky above.
After a long silence, he slowly spoke.
"Burn it."
"...Pardon?"
"Burn everything we prepared. The reagents. The samples. The records. Dispose of all of it."
The disciples' footsteps froze in place.
"T-Teacher?"
Erpen turned slowly to face his disciples.
In those blue eyes was something unusual — a faint, quiet self-deprecation.
"It was a shameful three months. The moment a junior scholar's hypothesis surfaced in this field, this old man's first instinct was not to consider whether it was right or wrong — it was to calculate what damage it might do to my three hundred years. Out of fear that my bloodletting might be proven wrong, I spent my time scheming how to bring that hypothesis down."
Silence fell over the disciples.
"Blinded by self-preservation, I spent three months — shamefully — preparing nothing but experiments designed to force a refutation. There is no greater disgrace."
The foremost disciple bit his lip.
"Even so, it has been three months, Teacher. The cost of the reagents alone—"
"Yes. Three months."
Erpen smiled gently.
"Should this old man spend the next several hundred years in shame, all to spare three months?"
The disciples fell silent.
"Do not look at me like that."
The aged elf, who had lived three hundred years, reached out and placed one hand slowly on the carriage door.
"Even the Saint acknowledged his mistakes. How much longer can I drag my three hundred years around with me, making them something ugly? I am still a person. I must face the fact that I can be wrong."
A rueful smile settled on that weathered face.
"Let three hundred years of ignorance be covered by new discovery. Prepare a new experiment."
"What kind of experiment?"
"Germs may yet be found in blood. Let us try finding germs in the blood of febrile patients, following the method the Saint described. Our own patients kept developing fevers during bloodletting — that's been a persistent problem, hasn't it."
Bloodletting was the act of drawing blood.
Removing toxins carried in the blood, then regenerating fresh, clean blood through divine magic.
To borrow Yulian's phrasing: Erpen's bloodletting was, in essence, a form of emergency dialysis.
The trouble was that for lack of attention to hygiene, even after the toxins were extracted, patients frequently developed fevers.
This had been a problem that humoral theory could not explain.
But perhaps those fevers could be explained by germs.
"If germs within the blood were indeed the problem, it would be worth researching a means of preventing it together with the Saint."
"Understood, Teacher!"
The disciples looked at their teacher with eyes full of overwhelming emotion.
Erpen, standing at the center of those gazes, stepped up onto the carriage footboard with a bitter smile.
It was then.
"Archbishop Erpen."
"...Archbishop Dormund."
The elf healer turned at the voice calling from behind him.
A white-haired old man, looking older than Erpen, was watching him.
Dormund's expression was grave as he spoke.
"Archbishop Erpen, there is something I must urgently speak with you about."
"Say it."
"Germ theory is... a far too dangerous theory. It may bring harm to the prestige of the Order."
Hearing those words, Archbishop Erpen had no choice but to close his eyes.