The bewilderment was...
only momentary.
Is it just a day or two that these guys have been acting absurd?
Moreover, it's not the first or second time that knowledge I thought didn't exist actually does.
Even from hundreds of years ago?
Thanks to that, I quickly regained my composure.
Of course, I had to satisfy my curiosity.
"That's something Blundell knows much better about."
"Hmm, hmm. I'm quite sharp in this area too."
"You think I made and sold that Rust Vane thing or whatever for nothing? Although now they've all become useless items..."
"Failure naturally follows science, after all."
As expected, it was Blundell who launched into the detailed explanation.
Originally, Liston knows people well, and Blundell is the one who knows well about things that actually happened, right?
Today was no exception.
"Now, now. To understand this first... you probably have a rough idea. But do you know how atmospheric pressure was measured?"
Anyway, listening to Blundell's explanation, my first thought was, 'How does he even know that?'
So I looked around with a face seeking agreement, but what do you know?
It seemed like everyone knew except me.
Crazy...
Really?
"It goes back to the year 1643."
Of course, I'm a master at pretending to know, so I could just nod with a face that said I knew all about it.
Inwardly, though...
_'1643? That's almost 200 years ago?'_
I was very surprised.
Come to think of it, Boyle, who announced Boyle's law, was roughly around that time too...
But knowing something in your head and actually feeling it are bound to feel very different.
The 19th century is already old...
To think they already did something even earlier than that, isn't it amazing?
"That gentleman used mercury to measure atmospheric pressure. He proved that the force that lifts mercury about 30 inches is equal to atmospheric pressure... After that, everyone with a tube tried to measure pressure. Coincidentally, since we had just discovered that the heart pumps blood out through blood vessels, which are like water pipes, we measured blood pressure too."
They even measured blood pressure, he says.
But they just weren't using it.
Thinking about it, it's not completely incomprehensible.
If I were my former self, I would have started by cursing, calling these uncivilized 19th-century bastards...
But the current me has immense understanding.
_'Well... what good is it to know what normal blood pressure is? There's absolutely no way to know about things like hypertension or hypotension.'_
I had reached the point where I could understand that if the background knowledge is too lacking, one doesn't even realize the importance of blood pressure.
"Ah, really? There's a way to measure it?"
"There is."
"Then shall we measure it right away? Senior Alfred?"
"Ah... blood pressure can only be measured exactly once."
But who am I?
I'm a doctor who was quite skilled even in the 21st century.
If someone like me starts measuring blood pressure...
It would create a tremendous synergy.
So I asked, and a very strange answer came back.
As I've said repeatedly, since this isn't the first or second time, instead of being flustered, I could calmly ask back.
"What does that mean?"
"Well, well... I thought you knew since you were nodding, but I guess not. Haha."
"No..."
"What is atmospheric pressure? It's the force that pushes mercury up through a thin tube, right?"
"Yes."
"Then what is blood pressure? It's the force that pushes blood up through a thin tube. What do you think we have to do to measure that?"
The first thing that came to mind was, of course, the familiar shape of a blood pressure monitor.
I haven't used a manual one since I was a student, nowadays they're all automated, right?
The machine came to mind.
However... when he said it's the force pushing blood through a thin tube, something slightly different eventually came to mind.
It was a thought that seemed like it shouldn't be thought of... that kind of thought.
"Don't tell me...?"
"If we insert a tube bent at a right angle like this into a blood vessel, wouldn't we just see how high the blood rises?"
"Ah..."
Crazy...
This is a blood fountain.
Don't tell me they actually tried it?
Ah, probably not... but this time, Liston, who is strong on 'people' or 'anecdotes', stepped in.
"Was it 100 years ago? I've heard a story that a pastor named Hales inserted a pipe into a horse's artery and measured the height of the spouting column of blood."
"Ah... what happened to that horse?"
"It died. That's why there's a saying that blood pressure can only be measured once."
"Ah... I assume they haven't tried it on a person?"
"They haven't. Officially."
"Ah..."
Right, no matter how crazy they are, they probably didn't publicly attempt that method of measuring blood pressure on a person.
Although, judging by Liston's words, it seems like a few bastards might have tried it behind the scenes...
One might ask how a doctor could do such a thing...
But among the doctors here, there are many who are similar to mad scientists—guys who don't really grasp the difference between saving lives and satisfying their own curiosity.
"So, measuring that is a nonsensical endeavor. Moreover, what do you accomplish by measuring it? It's nothing more than satisfying mere curiosity, isn't it?"
"No."
No.
Blood pressure...
The information it provides by itself is immense.
If a perfectly fine person's blood pressure drops, doesn't it mean they've lost blood, or their blood vessels have dilated due to infection or something?
Conversely, if blood pressure suddenly rises, it suggests they've engaged in corresponding activity, or pain has occurred, or something in the head has been damaged.
It's a vital sign that provides a great deal of information...
_'But no matter what, measuring it in a way that kills the patient is unacceptable.'_
What if I insert a very thin tube...?
Then...
No, it won't work.
To begin with, mercury and blood have different specific gravities.
If we roughly assume blood is similar to water... there's a 14-fold difference.
Since normal blood pressure is 120mmHg... that means it would spurt up 2 meters.
2 meters...
_'Just the diameter of my syringe is almost...'_
They'd die.
Even if they didn't die, they'd come close to death.
It's not like we'd measure every patient's blood pressure, only the unwell ones, and if we waste blood like that, it would actually be harmful.
Frankly, measuring blood pressure isn't a treatment itself, it's just a test, so taking a risk that could kill the patient is a bit much.
_'How on earth did we measure blood pressure...?'_
Certainly, the most definitive method for measuring blood pressure is inserting a tube into the blood vessel, as Blundell said.
But modern medicine doesn't measure it that way, right?
If it did, hospitals would still be places of lamentation.
They must have developed some groundbreaking... method...
_'I should have gone to engineering school.'_
If I had known I'd really regress to the 19th century, I would have gone to engineering school.
And chemistry department too.
But I didn't go, did I?
Worrying is a utterly useless endeavor, that's what I'm saying.
Those who have taken tests know... when you look at a problem, you just don't know, right?
Then, no matter how much time you drag on, you usually still don't know.
Those who get the answer at the very last minute are never the ones who do well on tests, that's what I'm saying.
"What are you thinking about so deeply again? You're not planning to measure blood pressure on convicts, are you?"
"No..."
"No, you're not. Hmm... that might actually be a good idea. It would certainly be worth seeing."
"No, no. That won't do."
'Worth seeing'...?
Is that something to say while watching people's blood spurt?
I looked at Liston with eyes full of reproach, and Liston looked back at me with a disbelieving face.
"Why not?"
"Pardon?"
"Arsenic dresses are okay, so why is this not okay?"
"Ah... that was to reveal the danger of arsenic. There was a justification."
"Haha. Blood pressure has a justification too. I'm curious. Human blood pressure... just how high would human blood spurt? How different is it from a horse or a dog?"
Then he said something quite persuasive.
To be honest, I almost fell for it.
If Liston's expression hadn't been so much like a mad scientist, I might have considered trying it.
"I'm curious about that too."
Since Blundell also chimed in, if they really wanted to do it, they probably could.
If the three of us said let's do it, it was obvious that the police or people like Sir Jamie, the influential figures of London, would also move.
Moreover, a blood fountain...
In an era that even considers surgical duels in the square as entertainment, if we made a fountain using heinous criminals, they'd probably love it to death.
Maybe they'd even make it a permanent attraction right in the middle of the square, a famous landmark and tourist spot of London.
_'No, that won't do. Why did I imagine it in such detail?'_
It seems a demon has possessed my heart.
I shook my head, consciously pressed my head firmly, and also pressed the forearm muscles that had tightened up from performing surgery earlier.
I don't know if it's because of Liston...
Maybe because my strength has improved along with his, it wasn't even that difficult to press so hard that my forearm turned white.
"Hmm. Hmm?"
"Why are you doing that again?"
It turns white.
Something, something.
Something feels like it's coming to mind.
"I said, why are you doing that?"
"Brother, be quiet for a moment."
"Hey, this guy is at it again."
"No, Liston. Be quiet for a bit. Pyeong is..."
"Ah... Ahh. Has the Lord arrived?!"
I closed my eyes for a moment.
I did so because I knew well that I couldn't solve this with just my own thoughts, that is, with my own abilities alone.
Should I call it recollection?
Yes, I did my best to recall knowledge that I already possessed but wasn't consciously aware of.
It must be somewhere.
Whether I picked it up somewhere or studied it in passing...
It's impossible that I never once looked into the principle of the blood pressure monitor.
_'Turning white means... blood isn't flowing.'_
It's true I might never have formally studied the principle of measuring blood pressure.
But if I combine the modern knowledge I have learned...
It's bound to be much easier than these 19th-century people trying to figure it out from scratch.
_'That means the force I'm applying... is so strong that it's compressing the blood vessel. The force the blood vessel withstands is the force of the blood pressing on the blood vessel. Which means.'_
I think I get it.
Yes, that's it.
When you measure blood pressure, you squeeze the arm tightly, right?
Why would you squeeze it?
Uh, right, you squeeze it to stop the blood flow.
But why would you stop the blood flow for no reason...
_'The force we applied when the blood just stops flowing is precisely the patient's blood pressure. Right.'_
Fuck...
I might really be a genius.
No matter how much future knowledge I have, I don't think I ever specifically studied this, but to figure it out just by massaging my forearm? Does that even make sense?
"Hehe."
"Is this the Lord too? It sounds like a Satanic laugh."
"Have you heard the Lord's laugh? How would you know?"
"But today the possession seems a bit long..."
"Has his skill improved in this short time?"
Laughter flowed out spontaneously.
Strange words reach my ears, but it's okay.
No, actually, it's not okay.
If these guys had just a little more common sense...!
Then I could have boasted as much as I wanted...
But since they are guys who know nothing, it's a pity that I can't.
Anyway, I opened my eyes.
"We need to make a blood pressure monitor."
"D-did He leave?"
"Who, ah, the Lord?"
"Yeah."
"He's gone. But He left a revelation. We don't need to insert tubes... Go quickly and fetch the blacksmith and guys who are good at making things like this."
"In the name of my Lord, I will definitely fetch them."