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In Vivo

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“Don’t be ridiculous, John.”

“Ridiculous? Me?” John snorted and snapped the newspaper to the next page. If he continued to mutter under his breath about absurdity and cheekbones and idiot geniuses, Sherlock chose to ignore it and plowed on.

“All of the biochemical studies have been more than supportive of oxidative stressors affecting the radicalization of tissues, resulting in toxic metabolites and harmful mutagens.”

John sighed heavily and continued to pretend to read the paper.

“Beyond which, carbamylation and lipid peroxidation predate the expertise to study them. So to suggest that I am aggrandizing the role of something so ubiquitous as endogenous 6-Hydroxydopamine is hyperbolic at best.”

“At best?” John twisted in his chair and cocked a brow.

“Downright idiotic is another way of putting it,” Sherlock huffed and changed the slide in his microscope.

“Do you even listen to yourself?”

“John,” Sherlock complained, straightening his posture. “Don’t be stupid. You know how effective conductive hearing is. You are supposed to be a doctor.”

That did it. John pushed himself out of the chair and stalked to the kitchen, stilling himself in the entryway as though bracing for a hit. “I am a doctor, Sherlock.”

The corner of Sherlock’s mouth twitched. “You don’t think like one. If you did, you would have considered the recent works on interleukin-6 and mitochondrial dysfunction in the dysregulated immune responses that’s been coming out of Aberdeen.”

John’s lips pulled back into an unimpressed smile that showed too much teeth. “Sherlock, you aren’t going to scare me off with big words. So stop trying. And I have read about that. It was published over four years ago. I thought it was interesting what they were doing with the animal models in Cambridge.”

Sherlock scoffed. “Yes but deltamethrin-“

“Don’t you deltamethrin me,” John crossed his arms. “This is the ascorbic acid argument all over again.”

“It is not the vitamin C argument!” Sherlock rolled his eyes. “It is hardly my fault if you fail to see the trees for the forest.”

“It’s forest for the trees, Sherlock. That saying is more about getting so caught up in minutiae that you can’t see the larger picture.”

“Preposterous. I think I would know the essence of that particular maxim.”

“Yes, because you are so spectacular at interpreting old adage.”

“Then enlighten me, John.” Sherlock pushed back from the microscope, twisting on the stool to shoot a vicious glare across the few feet that still separated them. “Show me your Gestalt wisdom here.”

“Gestalt? Sherlock, you can’t just take the human body and boil it down to parts. We’ve been over this before!”

“And yet you continuously fail to learn.”

“Me?!” John narrowed his eyes. “In vivo, Sherlock.”

Sherlock flapped one hand in John’s direction and made a rude noise.

In vivo versus in vitro. How is this a difficult concept for you?”

“Nothing is a difficult concept for me. Maybe you’re wrong?” Sherlock pouted sarcastically.

“Life can’t be studied behind glass!” John threw his hands up in exasperation. “You’re not this thick. Stop mocking biology.”

“Mocking biology? If a science doesn’t elicit reproducible results, then what good is it?”

“No,” John waggled a finger at him. “No, no. You don’t get to pull that card, Mr. I-Accidently-Set-the-Sink-on-Fire-Last-Week. And don’t even think about pretending that you meant to do it either. I saw the look on your face when you nearly lost your eyebrows.”

Sherlock scowled. “Then by all means, correct me, doctor.”

John clenched his jaw against the warm flush threatening to spread up the back of his neck and opted to stare at Sherlock in silence. It was only a few seconds of silent stillness before Sherlock started squirming. Quiet, he had called it. John’s quiet was something Sherlock found infuriating. Partially, because he knew John wasn’t actually as placid as he looked, and partially because John did it on purpose. To annoy.



“Yes,” John gave a firm nod. “You know, the extremely alkaline, oxidizing, cleaning agent that… Oh, wait, maybe you aren’t familiar with it.”

“I know what bleach is, John,” Sherlock said flatly.

“Good. Then you know it has a rather high pH?”

“Depending on the preparation, twelve isn’t unheard of.”

John flashed a rather mercenary smile. “Then you would also know that it’s quite a powerful antibiotic.”

“Antibiotic?” Sherlock wrinkled his nose.

“In the strictest definition of the term, it is. It destroys bacteria, eats through chitin, erodes steel, and disintegrates viral envelopes. So. Sherlock. It is quite the powerful antibiotic. Wouldn’t you agree?”

“In the strictest sense…”

“Good!” John snapped his fingers. “So why don’t we use it for pneumonia? For strep throat? For gangrene and herpes? It’d be horrifyingly effective.”

“If you wanted to kill a patient, there are far kinder ways than making them drink bleach,” Sherlock grumbled.

“They wouldn’t have to drink it. We could give it IV. I hear it’s an incredibly effective oncological chemotherapeutic agent. Works on pretty much any type of tumor.”

“So is napalm, John.”

“So is rattle snake venom,” John smiled sweetly and crossed the tiles to stand directly in front of Sherlock. “So, you see…”

“That’s not the point,” Sherlock huffed. “Your argument is ad absurdum.”

“It’s really not.”

“Rattle snake venom?”

John pushed his tongue into his cheek to keep from grinning outright. “Not happy with the representation?”

This time, Sherlock’s moue of displeasure was genuine. “No.”

John tilted his head. “Alright.” He stepped forward, into the space between Sherlock’s knees. “How about this one then.” He lifted his hand to stroke through Sherlock’s hair, letting the curls weave between his fingers as Sherlock’s eyes fell shut. “Cutaneous mechanical nociceptors of the scalp.”

Sherlock hummed, “What of them?”

“Most people would say that their stimulation is… unpleasant?”

“Most people would be right.”

John clenched his fingers, holding a fist full of hair tightly in his hand and tugged just hard enough to force Sherlock’s neck into extension. Sherlock’s lips parted in a sharp exhale as his eyes fluttered open. John very slowly cocked his eyebrow, watching the delicate flush bloom over the crest of Sherlock’s cheekbones and the black envelop the iris as his pupils dilated. “Then tell me to stop.”

It was only a slight movement, a scanty shake of his head. Maybe a show of caution against the threat of losing a few strands of hair should he move further. Not that Sherlock was particularly cautious when it came to his own well-being. “No.”

“And your stereocilia and kinocilium and cadherin tip links. How many times have they triggered a positive deflection for you to hear me tell you to tidy after yourself?”

“Thousands,” Sherlock breathed.



“Habituated.” John pressed forward, bringing his mouth to Sherlock’s ear and dropping his voice as low and as gravelly as possible. “Sherlock Holmes,” he growled. “Clean up your mess.”

“John,” Sherlock shuddered and closed his eyes again.

John brought his free hand up, his palm hovering beside Sherlock’s cheek without touching it and traced the pad of his thumb lightly along the lower border of Sherlock’s lip. “And your over-abused, posterior column-medial lemniscus pathway.”

“John, please.”

“Spending all its time trying to tell the difference between this, and this,” he replaced his thumb with the tip of his tongue.

Sherlock whined.

He shifted, dragging the tip of his nose across Sherlock’s cheek, down his jaw, along his neck to nuzzle into his pulse point. “Why is that?” he breathed into Sherlock’s skin.

“I-in vivo?” Sherlock offered, framing John’s hips between his palms.

“In vivo,” John pressed a light kiss to the side of Sherlock’s neck. “So I’m right?”

Sherlock growled.

John laughed and nipped at the spot he’d been nuzzling. Sherlock’s growl turned into a groan. “I am right.”

“I’ll concede the point if you find something better to do with your mouth,” Sherlock hissed.

“Shut up,” John lipped his way back up Sherlock’s neck to his chin.

“You shut up,” Sherlock tipped his chin up further, offering his mouth rather urgently as the something better for John. And while the flat was far from silent, what followed did not, in fact, involve much talking.