Nodding to Thia, Corti recites the letter then fumbles some spare paper out of her bag and bends over it with the other two women.

Tarian and Corti you figure that the cut off words make most sense to be single words. You figure the message is likely to read

"...oll root makes the poison less potent, but touch alone suffices for effects to take root. Be careful not to get ... into any open wound... If one of your own gets sick, ... them with a tonic ... ... silverbark. 

... the pulp, before filter... ...s the substance can otherwise act as a potent poison on its own."

You're pretty sure that the root doesn't refer to knoll roots, as they are a common food staple for the poor in Thrane, and you aren't aware of any poisonous effects of the root. Plimsoll root is supposed to have healing properties, and hence could be responsible for lessening the effect of the poison. On the other hand, troll root sap is poisonous to the touch, and adding it could result in a less toxic poison that could however also be administered by touch alone.

Gyselle and Thia, please give me an Intelligence (Medicine) roll. Thia, you roll with advantage,

Intelligence medicine roll take 2: 17

Thia, whether its the feverish thoughts or the mental focus on the task ahead after days of relatively monotonous activity, but your mind is racing and you start to make plenty of connections.

 Tarian, you puzzle over the rest of the gaps, particularly those of the second part, containing information on the processing of the ingredients. The latter part of the message seems to be a warning that the remedy itself might be dangerous, if not treated the right way, so in order to avoid mishaps, it was crucial to figure out how to fill those last blanks. The two latter ones aren't too difficult, and you determine that it makes the most sense for the sentence to read:

..... the pulp, before filterING, As the substance can otherwise act as a potent poison on its own."

Similarly the remaining gaps in the text above are easily guessed at too:

"...oll root makes the poison less potent, but touch alone suffices for effects to take root. Be careful not to get ANY or IT into any open woundS. If one of your own gets sick, TREAT them with a tonic OF silverbark."

Only two gaps remaining, but both important ones. Thinking back on your knowledge of plants though, you've never heard of Plimsoll root to be poisonous, while troll root was know to be poisonous to the touch. It simply made more sense for the missing word to be Troll root, and not Plimsoll root.

For the last part, the instructions were tricky, but a lot of things could be excluded: Filtering the pulp made no sense, as that was mentioned in the next step. Mashing the pulp seemd redundant, and the instructions so far hadn't been. Water down the pulp before filtering could make sense, but seemed unlikely because the smudged part didn't look large enough for two words. As you're looking over at the strips of bark that are being removed, carefully accepting them from the lancers and from Gyselle, you notice that the bark contains several dead worms and other critters, but only superficial damage to the bark. It looked like the part about the silverbark on its own being poisonous was true, but then how could you get around that?

A pang of hunger interrupts you, before you suddenly have an idea yourself: potatoes were poisonous if eaten raw, but boil them and they're perfectly fine. Maybe that applied to the silverbark pulp as well?

Her mind was racing, but it has also been foggy. Why couldn't she have thought of it earlier? Thia would swallow. She'd take a moment to digest her epiphany, making sure to jot down her though process in her notes so that she could run it by the others... She had too. Because that would mean... The medic would shake her head. Focus.

Thia would look around, ensuring that any of the lancers were out of earshot and sight, she'd stand up. With tentative steps, she'd approach Corti hovering over Gyselle and Tarian. She'd take a breath before clearing her throat and gently tapping on Corti's shoulder. The medic would give her friend a sheepish smile with tired eyes when she'd look up with her notes in hand, gently offering them for her to review first. Corti could pass them along when she was done if she'd like.

Thia would then glance to Gyselle before landing on Tarian. "How are you all making out?" She'd ask quietly.

Insight/Medince:19

Gyselle is curious about Thia’s behavior and tries to recall what malady could be affecting her. 

Gyselle, looking at Thia, you notice that she is shivering despite beads of sweat on her forehead and on top of her lip. The hand she extends with her notes on is shaking, and her voice sounds weak and croaky. She was either ill, or poisoned too. But how could that be? You had eaten the same things she had...

Gyselle thinks back to entering Hadrari’s (sp?) tent. The group used uniforms collected from the laundry tent. Perhaps she came into contact with it while wearing the uniform... and Corti is made of metal ... or mostly metal. “Thia I think you may be suffering from the same illness as the soldiers...” Gyselle says quietly whispering into her ear. Not wanting to alarm the others if her suspicions turn out to be incorrect. 

When Gyselle approached her with a quiet whisper, Thia would exhale lightly with a solemn nod. She’d known. It was just a bit sobering to hear it come from another. “Yes... I know.” She’d say quietly, swallowing. The medic would turn to look at Gyselle. After a quiet moment, she’d add, “From your treatment.” Slowly, Thia would gesture with her chin towards her notes held in Corti’s hand.

”So. Have you found anything towards the solution?” Thia’s expression and tone reset back to business.

“Yes, I think so.” Tarian calmly nodded and looked over Corti’s shoulder at Thia’s notes. Her eyes went wide. Uniforms washed in same manner. Eventually all soldiers would come into contact. “That—but, didn’t you…?” she sputtered. “I think we should do a field test of this medicine right now.”

Tarian quickly filled in Thia about her deductions. “Corti, we’ll need a fire, and water on to boil. And I’ll find something to work as mortar and pestle.” Tarian started digging through her bag. “Silverbark can be poisonous. Since I… have some experience… dealing with poisons, I’ll pulp the silverbark…”

As her hands rushed through her bag, Tarian looked to Thia. “Miss Thia, I hope we can rely on you for better instructions on the tonic. I could fumble through it, but I’d rather it be done right.”

Tarian left unsaid what she knew was better left unsaid. But somewhere within her, there still lingered that doubt. Gyselle requisitioned the uniforms.

Corti turns when Thia taps her shoulder, accepting the notes and placing a hand on Thia's back to draw her into the circle. She frowns at the notes, then turns them so Tarian can read. She sees the others' faces, then remembers Thia's exhaustion throughout the trip. "Oh... oh my goodness." Corti snaps to attention at the realization, and turns to Thia, pushing the notes on the letter's gaps into the artificer's hands. She nods to Tarian, "I'm on it." She pauses before heading into the trees, "If anything needs to be sterilized, bring it to me."

Corti will gather firewood as quickly as possible, avoiding the silverbark trees, and clear a space for the fire. She begins boiling a cooking pot of water, and as she waits she pauses, reflecting on her magic and ensuring that she's ready to heal, if necessary.

Together, you quickly get everything ready for the creation of a test sample of the tonic, with the lancers giving you plenty of space. Corti quickly finds some branches that were only partially burnt, as well as dried grass for tinder, and after piling them up into a neat little pyramid quickly gets a fire and a boiling pot going. Tarian, you find your own mortar and pestle within your travelling gear after a bit, and you start to chop up the bark and then grind it to a pulp.

Thia, you can provide help to the further steps in creating the tonic. Please indicate the steps you want to take and then give a herbalism check, for anyone proficient in the skill.

She knows... how does she know? ... Gyselle’s mind slowly begins ruminating on all of the information that’s been presented to her. It wasn’t until the cold look from Thia followed by ... ‘from your treatment’ that the information would truly sink in.

I ... I ... hurt someone I was trying to help... for anyone watching the exchange it is completely obvious Gyselle looks mortally crestfallen. Why? ... How? ... But I did everything right? What good can possibly come from this? Gyselle wonders to herself as she slowly moves away from the bustle of everyone trying to get everything set up to prepare the cure.

Gyselle’s very close to tears, though no one is likely to notice as she is facing away from the group and sitting on the ground. Alone. And in a stupor.

Fool. How could you not have noticed? No one was ever getting any better. They only got worse... Some medic you turned out to be... Her thoughts continued in such a manner only getting progressively more negative. Eventually she reached a point where the tears started flowing and as she does the sky in front of her opens up and it begins to rain. create or destroy water

(I intend to be far enough away that this wouldn’t affect or interfere with anything the others are doing. It would fill a 30 foot cube and be centered on Gyselle. So she would have walked at least 20ft away from everyone. Not sure how long it would last. Spell says instantaneous.)

As the rain begins to fall on Gyselle, she buries her face in her hands and sits there sobbing uncontrollably.

As Corti watches Tarian grind the bark, she pulls her lute out and begins playing to give Thia bardic inspiration. She keeps it simple and soft, not wanting to distract Thia and Tarian. As she plays, she hears the rain begin to fall and looks up, concerned, her fingers slipping briefly on the frets before locating the source of the noise. Oh... Corti doesn't leave the fire, but promises herself that she'll talk to Gyselle once everything is under control, repeating comforting mantras in her head as she finishes the song, I'm sure she didn't mean anything by it. Everything will be fine. Thia's the best medic you know, and Tarian's good at everything. They can do this.

 Tarian took special care with her hatchet to clean and then divide a small section of silverbark along the grain into narrow strips, then ground it down a bit, into smaller, pulpy bits. She piled the mess into a small, silken cloth, tied it off, and eased it into the boiling water. As the bag steeped in the boiling water, she sat next to Thia. "So, a tonic of silverbark. The pulp's boiling, so... do we have you drink the water it's boiling in, squeeze out the pulp and have you drink that, or combine the two? I haven't made this before, so..." Her voice sounded uncertain.

Corti, unfortunately you cannot determine whether the lancers are sick. They appear stronger and healthier than Thia though.

Tarian, together with Thia, you both manage to prepare one kettle of the tonic, eventually deciding to discard the pulped and boiled silverbark. Unfortunately, the letter does not provide any indication as to administration of the tonic, or the correct dose. But you are fairly certain that you managed to create the tonic as per the instructions.

Thia, how much of the tonic do youwish to drink?