“That’s it, Slime-bro,” I encouraged, anticipation welling within. “Keep going… you’ve almost got it – no!”

Right when Slime-bro’s inwardly folded membrane had been about to join together, fuse, and hopefully release a small slime-bleb, he had abruptly lost control of himself, made a spasmodic motion of his gelatinous form, a jiggle-like movement being propagated through him, and reverted back to his original form.

“Bad Slime-bro! Bad!” I scolded, glaring at him unhappily. “You were so close, too! Shame on you! Shame!”

He hung his head – err, body – down dejectedly, but I was too annoyed at him to care. Another week of experimentation, and Slime-bro hadn’t yet figured it out. He had been so close – just another few centimetres, and I would have finally obtained a piece of Slime-bro’s membrane, ready to be expanded, multiplied, and cultured with impunity.

I had a theory going on, now. Based on my rather inaccurate measurements of various other Slimes’ bodies, the lowest osmotic potential they could go to before they burst, and a post-mortem analysis of the cellular junctions of their skin, I now believed that the maximum size that could be reached by a Slime was dependent on whatever internal pressure its membrane could manage to withstand. When they were close to dividing, their size would increase as they swelled up with fluid, associated with the appropriate change in membrane organisation.

Post-division, as fluid distributed between the two progeny Slimes, the membrane structure would return to what it was like in the Slime’s ‘growth’ phase, as I now termed it. G1 phase, drawing inspiration from standard cell cycle nomenclature. From there, it would continue absorbing fluid until it reached the size determined by its membrane structure, prepare for division, and the cycle would continue.

Strangely, though, Slime-bro never once divided, despite him being due for a division cycle. Not just that, his size could vary by changing the cellular junctions of his membrane structure, although he hit a hard cap in size when his membrane tightness was as high as he could go, at about the size of a toddler. It was yet another sign that Slime-bro was special. Despite my efforts in studying and observing him as he displayed behaviour more intelligent than his peers, and yet far less than even a child, the exact reason as to why he was so unique among the Slimes I encountered still evaded me.

For now, though, I would be satisfied with what I had. If Slime-bro’s membrane thickness could be increased, there was a possibility that he could become a huge Slime-bro. Not too large, of course – if the layers became too thick, the exchange of solutes between the internal reservoir that formed the Slime’s liquid core and the actual cellular membranes on the outside wouldn’t be efficient enough to support life.

Fick’s law of diffusion in action, baby. I had honestly no idea how thick Slime-bro could become, since I still had no clue how magic factored into any of this, but needless to say my earlier expectations of hoping that he could become a golem-like slimy juggernaut of destruction had been thoroughly dashed in light of these findings.

Well… there’s still a chance, though, I thought, considering more carefully. If gap junctions and connexin complexes connected all the cells of the Slime’s body together, the limit would be raised slightly higher, since they would effectively be sharing what served as their cytoplasm together. That would overcome the slower rate at which solutes could be transported across different phases, as it traversed from cell to cell through cytoplasm and cell membranes. Still, there would eventually reach a limit whereby diffusion through liquid would be unable to support the outermost layer of cells.

A hurdle to cross once that time actually came, I supposed.

…how the hell had I gone from common tumour immunologist to considering the feasibility of creating Golem-Slimes?!

That’s it – I needed a break from thinking about Slime membranes.

“Reflect on your mistakes, Slime-bro,” I warned. “Or else I won’t be feeding you the sweet nectar of life harvested from the bodies of your dead kin.”

Message delivered, I went on to the experiment that was next on my agenda for today.

It was now close to a good month since I settled into this world. Unfortunately, during that time, my level stubbornly remained at Level 4, which meant that I had no new skills to play with. From what I understood, levels increased as people engaged in combat, much like a standard video game, or if they committed themselves to the professions aligned with their class. Kind of like in Runescape, actually, now that I thought about it.

Over the past month, I had mostly committed myself to studying Slime biology. Project: Slime was taking far longer than I initially envisioned, but at least I had other experiments that took my attention. Today was when one of them might finally come into fruition.

Project: Liquid Fire had been my secondary focus over the past week. Needless to say, the name was a work-in-progress.

The objective of this project was simple – I wanted to find out why Fire Eels retained an inherent fire-based magical ability in their flesh despite being aquatic animals, such that they could be used in the creation of Fire Oil by [Alchemists]. It was a step up from Slimes, and seemed to be diving into the territory of magical phenomena, but studying the interface where Biology and magic interacted was a hurdle I had to cross eventually.

Besides, it couldn’t be that hard, since Fire Oil wasn’t the most potent of Alchemical Oils – apparently, few people over Level 10 used it, preferring to go for more powerful variants of oils or enchantments at that point. As far as I knew, the only active ingredient was fish oil harvested from Fire Eel flesh, unlike other alchemical potions that might require dozens of different herbs.

I purchased a trio of Fire Eels from the resident [Alchemist] of the village that my laboratory was on the outskirts of, a man in his fifties by the name of Aksal (hence his store name, Aksal’s Alchemical Supplies, one that I heavily frequented despite not being an [Alchemist]). He’d been astonished by my request, seeing as Fire Eel flesh was notorious for being highly poisonous for culinary purposes, but a decent sum of gold was enough for him to contact his supplier and deliver a live shipment of the fish.

It didn’t do good for my reputation, and I’m pretty sure I heard some people in the shop call me a deranged oddball, but hey – what scientist hadn’t suffered from such derision before?

It put me at only half the gold I had started off with, though, after purchasing more equipment and plates as my tissue culture efforts increased in size. Soon, I knew I would need to make a breakthrough if I wanted to continue the self-funding of my experiments. Hopefully, these Fire Eels would be worth it.

I had a third project waiting to be embarked on, but thus far I had been continually procrastinating on starting it. I had tentatively named it Project: Money-Tree, because what I wanted to do with it was explore the properties of herbs used in low-grade potions. If the active compound that actually reacted with an [Alchemist’s] mana could be made known and expanded in the equivalent of a bio-reactor that I might be able to stitch together with my set-up… well, my finances might be just a little bit more comfortable.

The reason why I didn’t want to start on it?

Easy: I sucked at plant physiology. I honestly didn’t even know where to begin.

I knew virtually nothing on the subject, since my lectures at university had been focused mostly on humans, with comparisons to common experimental models. Animals were remarkably physiologically similar to one another when painted with broad strokes, and it wasn’t too difficult to extrapolate what I already knew from humans to other animals, and now to Slimes. Plants, however, were a different breed of beasts entirely. Heck, Dragons would probably be easier to understand than plants.

And therefore, much like how I kept delaying on one experiment throughout the course of my PhD because it just wasn’t interesting to me, I had continually kept Project: Money-Tree on the backburner. Sue me.

I kept a pair of Fire Eels for breeding purposes, a male and a female. The trouble there was that I had no idea how long it would take before I could obtain viable offspring. I might just run out of what research funds I had left before I had more samples to experiment on.

Therefore, with the third Fire Eel that I had allowed it to grow out for the past week, I knew I needed to make a breakthrough right here and now. I had been generously treating it with copious amounts of Slime broth, in the hopes that I would have access to more biological sample to test out various theories of mine.

And now, the time had finally come. My dissection kit was ready, along with Slime broth for collection and preservation of tissues. I would create Fire Eel cell lines from as many different tissues I could manage – simply because I could – but the real deciding factor was whether I could find out how and why Fire Eel flesh could be processed into Fire Oil through infusion of mana, both in terms of the technicalities that underpinned the process and the more philosophical musings of why an underwater fish would ever have the need for such a property.

“Come on, Slime-bro,” I said, almost reverently, scooping him up to let him rest on my shoulder. “Destiny awaits.”

-o-o-o-

I stared at my handiwork, hands filled with blood and stray bits of tissue. It had been messy and tiring, and I didn’t know whether or not the cells I had sent packing to tissue culture would actually survive with how long the dissection process had taken, but I was filled with a sense of awe all the same at what lay before me.

I didn’t know much about fish anatomy. My only experiences with dissection were cadaveric dissections on humans as part of my pre-clinical medical training, and on mice for retrieval of tissues during research work. In the end, though, the actual concept was the same: dissect as bluntly as possible, and preserve intact tissues as much as humanly feasible. A rookie mistake in dissection was making the initial incision far too deep, and hence destroying interesting structures in more superficial layers.

To [Alchemists], who only saw Fire Eels as a commodity for their flesh, they wouldn’t have bothered with blunt dissection. Taking as much tissue as possible, mashing them up, and then distilling out the actual fish oils was probably the best way to harvest the reagents required for generation of Fire Oil. Likewise, with Fire Eels being known to be highly poisonous, no one would care about taking the time to perform a thorough dissection. If anyone had ever discovered what I now saw before me, it certainly wasn’t noted in the bestiary I had read.

For in front of me, now placed inside two small tubes of Slime broth, were two separate pea-sized, shrivelled structures that I had found connected to either side of the fish’s mouth, almost hidden by its gills superficially and by its powerful teeth from within the oral cavity. They were pouch-like, with a narrow, almost indiscernible tube leading out from them, and it had only been due to [Bio-Analysis] that I had been able to actually physically see it. If I didn’t have the presence of mind to question what those pouches were, I would never have known what they could do.

Going by structure and definition alone, they were exocrine glands - structures that secreted substances out of the epithelial surface by means of a duct. In most cases, glands leading to the mouth were nothing abnormal: the parotid, sublingual, and submandibular glands all fed into the oral cavity in the vast majority of living animals.

Fish, however, did not possess salivary glands.

And though the two glands of the Fire Eel were separated almost equidistant apart from the centre of the mouth, they looked different in appearance. One was almost entirely black, while the other appeared a deep green.

In short, they had to contain different contents, leaking into the same space, for a purpose fundamentally different from the mundane fish I was used to. If that didn’t scream ‘Look at me! I’m important!’, I didn’t know what did.

Extremely carefully, I removed the small black gland from the tube with a pair of fine forceps, taking special care not to rupture the pea-sized sac. Already, some of its contents had to have leaked out through the narrow tube-like structure that fed its contents out to its mouth, but hopefully there would be sufficient left inside for a coherent analysis. Steadying my hands, I slit the sac open, letting it rest on the petri dish as a small, flat, circular sheet.

Even more carefully – if that was somehow possible – I scooped up the black, viscous fluid that lay within, not even a millilitre’s worth, placing it into a second tube. Then, I repeated what I had already done with the second gland.

With the laid-out sheets from the exocrine gland, I immersed them in culture media, and placed them reverently on the tissue culture side of the room. Having had some experience with growing tissue explants from the exocrine pancreata (yes, that was the plural of pancreas, and don’t let anyone tell you otherwise) of mice for study of acinar cells in pancreatic ductal adenocarcinoma, hopefully these culture conditions would be enough for them to grow out, followed by sub-cloning and optimisation of culture conditions.

Beside me, Slime-bro trilled in curiosity.

“If they grow out, I’ll collect their supernatant and carry out a proper purification for products expressed by these exocrine glands,” I spoke aloud, already stepping back for what I had saved for last. An anticipatory, almost predatory smile slowly formed on my face. “And if my theory is right… I think we’re going to see some awesome shit.”

Without further delay, I performed a [Bio-Analysis] on the pair of substances in front of me.

I couldn’t, of course, simply ask my skill what function the viscous fluid held. It just didn’t work like that – all it did was provide a means for me to obtain a measurement or observation of my desire without having to go through the middle step.

In this case, what I wanted to know was this: were they a ligand pair? Did their products interact with one another in any meaningful way?

And indeed, though I couldn’t even begin to comprehend what I was seeing through my skill, in the same way that the 3D model of a protein perplexed me, I could distinctly see how the molecular structures of the two primary products within the liquid fit together.

A memory surfaced within my mind, a little factoid I had once read, thought of as interesting, and never really bothered too much about again. The bombardier beetle had two large glands at the tip of its abdomen, the interior of which formed a large vestibule containing a mixture of catalase and peroxidase enzymes. Separated by a biological valve from this mixture was a reservoir made of an aqueous solution of hydroquinones and hydrogen peroxide.

When the beetle felt threatened, the walls of the gland contracted, opening the valve and allowing the aqueous solution to enter the vestibule. There, catalases decomposed the hydrogen peroxide, and peroxidases oxidised the hydroquinones. Together, both reactions were extremely exothermic, meaning that a large amount of heat was given off.

The exact chemistry was irrelevant: in the end, it could be summarised in a single sentence. Predator meets beetle, beetle squeezes gland, things come together, and a big boom happens. Within instants, the temperature of that mixture would reach the boiling point of water. The resultant pressure forces all that superheated fluid to be expelled out violently from the gland, fending off any would-be predators through the sheer pressure, heat, and caustic properties of the jet of fluid.

In other words, this fish here was no different. The products of the two glands reacted, and that was why the exocrine products fed into the same space… the fish’s mouth.

To what end, though? That was what I was going to now address.

Proper science demanded that I wear personal protective equipment at this point, but I was a poor, starving scientist who didn’t really care all that much for workplace safety. Besides, I had glasses on.

Who needed gloves, lab coat, and goggles, anyway? What could these liquids do, kill me?

With great care, I decanted a small volume of one liquid into a third tube – without tools like a micropipette, I couldn’t be exact of my measurements, but I was more interested in qualitative than quantitative results anyway. Who was going to bug me about my methods, a non-existent reviewer at a non-existent science journal of this world?

Then, I repeated the same feat with the second liquid, immediately taking three steps back as I did so–

A second passed.

Two seconds.

“Slurrrrrrp?”

…nothing happened. Slime-bro was craning itself forward on my shoulder, staring at the tube, but I had no idea if he actually understood what was going on here.

I frowned. Why? What had I missed?

I thought over what I already knew. The glands were small in size, almost shrivelled and near-invisible. Likewise, the ducts leading to the mouth had been so narrowed, that it was unlikely that they would have ever allowed any meaningful flow of the produced substance into the fish’s mouth. That was the main gross anatomical observation.

On the molecular side of things, their products were a pair capable of interacting with each other. They weren’t a receptor-ligand pair, it seemed, since they were freely floating in the viscous liquid, rather than being bound to any sort of cellular structure.

It explained why no one had ever discovered a potential reaction between the pair of substances produced by those glands, even if they had somehow taken special care to note their existence. Not only did they have to be brought in contact with each other, but a third extra step was required for their reaction to occur.

What was missing?

When in doubt… always fall back to other similar experimental models, draw comparisons, and devise theories to be tested. That was how scientists had developed their craft for centuries.

And so, my mind drifted to the exocrine organ I was most familiar with: the pancreas. Among its main products were lipase, amylase, and trypsin. It aided with the breakdown of digested macromolecules. Pancreatic insufficiency resulted in oily stools, due to the lack of lipase.

If these two fluids were like the lipase, amylase, and trypsin I was used to –

Wait.

Not trypsin.

Trypsinogen.

The pancreatic protease, trypsin, had to be synthesised in the inactive precursor form of trypsinogen, to prevent damage done to the pancreas itself. It was only when the exocrine fluid eventually entered the duodenum through the major duodenal papilla, that the inactive zymogen was converted to its active form by duodenal enteropeptidase. In pathologies such as certain types of pancreatitis, aberrant activation of trypsin within the pancreatic parenchyma resulted in tissue damage.

It was a safety mechanism… and this was no different. Like the bombardier beetle, there was a failsafe to prevent the fish from spontaneously blowing itself up, but here it wasn’t simply just the spatial separation of the reactive chemicals alone.

I knew without a shred of doubt that this had to be the case. Still, I would need to thoroughly test it. If it truly were that, then what exactly was it that activated this reaction?

The answer was obvious.

Heat.

This was why Fire Eel flesh, and the resultant oil distilled from it, gave rise to fire-based properties through alchemical processing. Somehow, mana, much like the fabled aether of the ancient philosopher-scientists, interacted with what I knew as normal biology to give rise to a supernatural phenomenon.

This was, after all, a magical world. While it was grounded in certain biological constants inherent to all life, magic transcended some of its limitations, making what was normally impossible or unviable on Earth now fully possible.

Excitement overpowered any trepidation I might have at what was to come next. Science was no fun without risk, after all. All the great scientists I admired surely thought the same. Barry Marshall, joint recipient of the 2005 Nobel Prize in Physiology or Medicine, had ingested a broth filled with Helicobacter pylori just to prove that it was the causative organism for stomach ulcers, and that antibiotics could cure it. Some called him a madman, but I beg to differ.

How could I call myself a [Biologist], if I wasn’t willing to do at least that much?

“Bottoms up, Slime-bro,” I whispered, and without further ado, turned on the magical Bunsen burner, grabbed the test tube containing a mixture of a small amount of each liquid with a pair of long tongs, and held it at arm’s length against the flame.

Within a split second, the reaction took hold.

Sparks flew, radiating a blinding white light.

A hiss of evolved gas…

…and with a loud, resounding boom, the test tube shattered. Startled, I leapt backward, just barely avoiding myself being nicked by shards of glass. It was almost like the time I played with sodium and water back in Chemistry class.

“Slurrrrp?” Slime-bro hissed, alarmed.

Barely a few drops of each liquid. That was all it took.

Why the hell would a Fire Eel possess something like that? That kind of heat and explosive strength was useless in its normal environment, so why –

Oh.

Ohhh.

“Holy shit,” I said, stunned. “Oh my God. Holy shit. Holy shit!”

“Sklreeurp!”

I understood it all, now. My thoughts were racing, ideas bouncing around within my head, feeding upon each other, all the observations and theories at last crystallising into something concrete.

The shrivelled sac and tubes – the fire element properties of the oil –

“Don’t you see, Slime-bro?!” I grabbed him harshly, shaking his jelly-like body about. I barely heard the ‘Slurrrrp!’ of displeasure that came from him. “Magic – Biology – it’s all there! It’s all been there the entire time!”

Perhaps it was a sign of sleep-deprivation, or how much the thought had gnawed at me for so long, that finding the answer to the question of just why the hell a fish would make fire drove me into such a crazed state of ecstasy. Whatever the reason, it didn’t matter to me in the slightest. I had grand ideas going forward now.

“Slurrrp?”

“Ah, right, right,” I said quickly, placing him back down on the table, smiling widely at him and his confused expression. Well, I thought he was confused at least – I wasn’t an expert in Slime social cues. “I suppose I should explain it to you, yeah? You know how oils made from Fire Eel flesh have a mild fire element property? The keyword there is mild.”

I patted Slime-bro gently on the head, marvelling at its cuteness as its eyes contorted into an adorable gesture of incomprehension. “For you see, that was never the primary purpose of that property at all, merely something that [Alchemists] saw the use of from Fire Eels. If my conjecture is correct, mana alone is sufficient to elicit heat from any living tissue of the Fire Eel; flesh is just the most abundant. This heat is just the trigger mechanism.”

I gestured grandly to what remained of the test tube, still held far away from myself with the tongs, smoke trailing from it. “This is the real deal. And the real beauty of it is this: Fire Eels don’t even actually use it!”

I stared expectantly at Slime-bro. His continued lack of comprehension didn’t deter me in the slightest. In time… in time he would understand.

“Don’t you see? The glands are vestigial structures! It… it’s brilliant!”

I flourished grandly, almost accidentally striking the table with my pair of tongs. That was a safety hazard. Quickly, I placed it on the benchtop, continuing on with my explanation. Cleaning up could come after.

“The glands and the ducts connected to them were all shrivelled up! The Fire Eel had no need for such a powerful defence mechanism in the habitat it lived in, and so over the long millennia of evolution it gradually receded. Much like the tail bone of humans, though, it was still hard-wired into its genetic code, and nothing could change that. And therefore, while its function is redundant for the Fire Eel now, those glands still survived over the eons, shrinking in size over generations as drift occurred because there wasn’t a selection pressure acting on that characteristic.

“But those glands… those glands are still functional, even if greatly diminished. They produce and store a miniscule amount of that compound, just that it is never secreted out through their exocrine ducts. You know what that means, don’t you, Slime-bro?”

“Slurrrp!”

“That’s right!” I cackled aloud, almost manic. “We discovered bio-magical thermite! If we optimise tissue culture conditions for these exocrine glands, we can literally make biological incendiary or concussive grenades! But there’s still a second important thing about these results, Slime-bro! Think!”

His face contorted, vibrating and jiggling, before he finally bounced once on the spot and gave a sharp screech.

“Slureeep!”

“Absolutely!” I knew Slime-bro was intelligent!

Looking back at this moment from the future, some rational part of me would probably wonder just what on Earth had made me think that Slime-bro actually knew a thing about what I was talking about, but driven by an unnatural manic high, I couldn’t care in the slightest. I was in my element now. I continued on, revealing the realisation that had sent shivers down my spine at the sheer potential it represented.

“Somewhere out there, there’s proooobably a distant evolutionary relative of the Fire Eel that has this defence and offense mechanism intact! They literally shoot out fiery bombs of doom from their mouths!” I declared grandly. “And one day, I’m going to find, capture, and study it!”

What could it be? Drakes? Dragons? But no, they couldn’t be the origin of these glands, even if they relied on that mechanism too – reptiles emerged later on the phylogenetic tree of life than aquatic fish. Unless every creature that had since descended from this ancestor that first made use of these glands no longer had a requirement for this purpose - an unlikely event, considering the sheer breadth of biodiversity - somewhere, somehow, there was likely to be an aquatic fish or related animal that made use of these glands the way their ancestors did. Perhaps there were even some with functions that diverged from this purpose, in the same way that the stapes of the middle ear in mammals was nothing more than glorified jaw support in fish, millenia of evolution having caused their functions to diverge.

I had no idea how such a creature would look like, or why it would make sense… high pressure underwater shockwaves, almost like a mantis shrimp, perhaps? Something to consider at a later time. More importantly, what I just discovered had earth-shattering importance.

Magic made things unsuitable for regular biology possible. This was an example of that – interaction of mana with Fire Eel tissue evolved heat, and that heat activated the normally inactive products of the two exocrine glands. It was too complex for the invisible hand of evolution for life on Earth, but magic bypassed that barrier.

I didn’t understand the magic part in the slightest. But the half that stemmed from Biology and the natural sciences?

That, I understood well.

The lightning from a Thunder Lizard’s horn, the elemental breaths of Drakes, the regenerative properties of a Hydra, the cute little Frankenstein's monsters that were wolpertingers… mysteries simply accepted as fact by adventurers and scholars, grouped under the black box of ‘magic’, could all be unveiled through the lens of Biology, and what rudimentary understanding I had of Chemistry and Physics.

“Slime-bro, you and me,” I said, grinning wickedly, bending down such that my eyes were level with his on the benchtop. “One day, we’re going to be Newt bloody Scamander, except our show will be Fantastic Beasts and How to Study Them.”