1810 England, the height of the Napoleonic wars. It was thought that humans walked the path of enlightenment leaving monsters and dark things behind. However, those monsters and night stalkers merely hide in the darkness, as a young maid, Bernadette, soon finds out.
Basically what she's saying is that the over-abundant energy in Jinny's body over-reacted to the alchemy and instead of just making Jinny strong enough to survive Angela's partaking of her blood and emotions, forced her body to grow to it's strongest point. Werewolf children are fragile when they're young, not so much as adults, when they can transform though.
As for the symbol Antimony, here is the definition: antimony was sometimes symbolized by the wolf. The metal antimony represents man's free spirit or animal nature.