Quiz

Is it possible, by experimenting on condemned prisoners, to identify a poisoned tank of kvass, given that even a negligible dose of poison is fatal, and the poison takes effect after 12 hours?

Yes, that's what theory suggests. It's possible to identify it if you're lucky, or it might not be possible. )))) This is the absolutely correct answer to the question. It can be identified, and it might not be.
Anyway, I'm thinking about a solution that would guarantee identification, regardless of luck...