My story is set in England, 1919, and involves an assassin trying to win a bet; he must kill the hostess of a party, without being detected, in the middle of her speech at a dinner party.
I think nicotine poisoning is my thing - I think it may be possible for a non-lethal dose to be delivered through the skin, via a tainted object (probably a wine glass stem), and a final, smaller dose delivered as the hostess smokes a cigarette to calm her nerves just before she makes her speech. I intend to have her suffer a seizure and respiratory failure and die quickly. (He, of course, loses the bet on the technicality that she delivered the fatal dose herself.)
While I've found a lot about the symptoms, and how the poison works, I haven't found much evidence that this method would work. I found references to a man hospitalised by sitting in spilled nicotine insecticide, but I don't know whether a smaller dose could be given, then "topped up" shortly after. She could be handed the tainted glass to drink from just as she is about to smoke, but again, would the effects be immediate, or does she have time to drink, smoke, get everyone's attention and begin speaking? I'm aware that inhaled nicotine reaches the brain in around 20 seconds, but are symptoms instant upon lethal dosage? Should she (and would be be socially acceptable to) smoke while speaking? And is the difference between the dose in a cigarette (anything up to 10mg, according to google) and the lethal dose (60mg) too narrow for this method to be practical?
I'm still reading up on poisons, so if this is simply no good, I'm sure I can come up with something else.
Searched terms: combinations of 'nicotine poisoning', 'nicotine absorption by skin', 'nicotine fatal doses', 'nicotine speed of absorption', 'nicotine speed of reaction', 'poisons absorbed by skin', 'unusual poisons'. Although it feels like I've been googling all evening.
Mods? There's nothing in the rules about whether we're allowed to tag our own posts, so I just haven't. But will if asked.