Granny Rags asks you to get the plague rot viscera from Dr Galvani’s house so you can poison the distillery that’s making black market health potions and get her revenge on the gentleman callers who keep coming to her house. Combination for the safe is also included.
Part 1: Obtaining the Plague Rot Viscera from Dr. Galvani’s House
The Doctor’s house is located between the 1st and 2nd Wall of Lights.
Once you enter the house, you either have the option of sneaking past the guards in the rooms to the right or left or you can kill them so you can get to the stairs all the way in the back.
In my opinion, it’s a really good idea to take the time to go through each room. You can stock up on ammo, health, mana, and coins.
In the room to the right, go all the way to the back to retrieve the Pantry Key (if you want to open the door in front of you) And the Lab key. The Lab key isn’t required, you can still access the lab from the side entrances if you find the Maid and loot her.
The combination to the safe on the second floor is 287 – Galvani’s favorite day: His Birthday
The third floor you gain access to your first spring razors (proximity based mines) and they can be equipped using your wheel
In the third room, find the bookshelf next to the globe. Find the book the gives you the option to pull and open the secret room
Grab the plague rot viscera and whatever else you want from that room then head back outside towards to the distillery and the second part of the quest.