The advantage also allows the Hero to perform Blood Science, which the text makes clear is a bastardization of the "world" part of the discipline. But the "more traditional" aspects of alchemy, it says, are discussed in the Rose & Cross book (I checked; while interesting, it wasn't what I wanted), and would be further explored in "later supplements."
They never got around to it, and there are no later supplements now. We're on our own.
So what to do? Ideally, I'd like to come up with some Alchemical "inventions" that you need this Advantage and the Alchemist skill from SD to come up with. Alchemists would have to either make Conception and Design rolls or find a formula somewhere, and would always have to make Construction rolls.
But I'd really like to base it in "real-world" alchemical traditions if at all possible.
Two ideas I've had, involving the Theory of Humours. Humours could conceivably be rendered from animal bodies; you'd need to purify them before using them on humans, but after that you could use them safely. A dose of Sanguine Humour would heal one Dramatic Wound, but would cause Overconfidence (like the Hubris) for a time. On the other hand, a dose of Choleric Humour would render the patient immune to sleep (or the need for it) for eight hours, after which he'd be normal but completely rested -- but for those eight hours, he'd also be Hot-Headed.
The other two Humours are Melancholic and Phlegmatic, but I'm not sure what their benefits would be. Melancholic would cause depression, but have some benefit related to endurance. Phlegmatic would enhance intellect in some way but cause apathy.
There are other alchemical products that were sought, such as Alkahest (the universal solvent), the Elixir of Life, and the ever-popular manufacture of gold. The ultimate quest on the physical plane was the Philosopher's Stone, the ultimate alchemical catalyst.
The theme of all these operations is to purify materials, bringing them closer to perfection.
If anyone is familiar with sources of gameable alchemy, please feel free to point me toward them. Ideas for the benefits of Melancholic and Phlegmatic Humours would be welcome as well.
As for the third leg of the discipline -- spiritual perfection -- maybe the ability to buy off a Hubris and/or buy a Virtue, at a tremendous XP cost, would work.
While we're coming up with ideas, though, let's not go overboard. Many of the 7S sourcebooks caution us against going overboard with inventions and Syrneth artifacts. We want a sense of wonder, but we want it to take a back seat to the swashbuckling.