I read somewhere that, if you get stranded somewhere and your last option is to eat some natural plants/fruits that you don't know, the rule was to take a small bite and wait for few hours. Most poisonous things would not kill you this way but will give you a hard time so you know it's not safe. Otherwise it's safe-ish to eat
I learned a similar but more cautious method in a jungle survival school:
Step 1: Touch the plant with your hand, wait 1 hour for negative effects to develop.
Step 2: If step 1 produces no negative effect, touch the plant to more sensitive skin, such as the inside of your forearm. Wait another hour for negative effects to develop.
Step 3: If step 2 produces no negative effect, touch the plant to the area around your mouth. Wait another hour.
Step 4: After touching your mouth with the unknown plant and seeing no ill effects, chew up a tiny bite of the plant in your mouth and spit it out, and then wait another hour.
Step 5: Ingest a tiny amount of the plant and wait an hour for negative effect.
Step 6: If no ill effects are felt at this point, the plant is likely safe for you to eat.
This is a very long and difficult process, but it's the safest way to determine if the plant will kill you. If you see a lot of one type of plant that you think you might be able to eat, it's worth the wait to figure out if it's poisonous or not. Once you've identified an edible plant, you can continue eating it without going through this process again.
Another general rule is that milky sap typically is poisonous, and you should definitely avoid fruit that has milky sap. And of course, if it tastes bad, that's probably a good sign that it might not be edible either.
I'd wait a lot longer than an hour after sampling a little. Many poisonous foods take a lot longer than that to take effect. I'd wait at least a day after tasting a little.
Also, often (always?) the poison's in the dose. A little might be safe to eat, more not so much. So I'd go really easy when eating something new.
Step 1 reminded me of an amusing problem:
- 16 bottles of wine, one has been poisoned.
- poison takes 1 hour to kill you, party is in 1 hour.
- you have 4 prisoners you don't mind sacrificing to find out which bottle is poisonous but obviously you'll need to do all your sampling now because otherwise you won't know which bottle not to use in time for the party.
I feel like this is solvable using binary to assign which bottles to which prisoners, but only if there were 16 bottles. For example, bottle 11 dec = 1011 bin. So bottle 11 would be tasted by prisoners 1, 3, and 4. Then if 1, 3, and 4 die, we know bottle 11 is poisoned. Every combination of prisoner deaths would point to a unique bottle.
That riddle is sometimes called "criminal cupbearers".
Common presentation uses 1000, gives it away to use a power of two.
A really fun extension to it is to suppose that you use the same criteria (a thousand bottles, consumption of the smallest amount will kill, but after a delay that means you must perform a one-pass test) but _two_ bottles are poisoned. What is the minimum number of prisoners you need for your test to find the two poisoned bottles precisely and what is the procedure?
I think it's obvious from the setup of the puzzle that the prisoners lives are completely expendable without repercussion. That kind of precludes any of the more liberal/modern methods of handling prisoners and leans more towards medieval-style prisons.
I don't disagree with you on the obviousness of the set-up. I'm drawing attention to the more subtle language structure which, by design, defines prisoners as non-persons.
I quite like the mathematics of the puzzle, I also like justice and am aware that justice is a product of language in many instances, as many people interact with the world through language without giving much thought to it.
... and as second goal, becoming a prisoner in jail some time later, for the cheap prize of some bottles of wine.
This is the kind of problems that AI machines would try to solve, wrongly. Humans still score better understanding that some theoretical problems must not be solved.
So you're probably not going to die without food if you go even for some days without it. In fact, many people regularly fast for days on end, some (such as people on hunger strikes) have fasted for weeks.
Of course, all of the above rules of thumb are subject to modifications based on things such as the amount of physical exertion you're under, your health, the weather, etc. If you're doing lots of exercise in the heat, you're going to need a lot more water than if you're lying still in the shade.
Not necessarily. Plants aren't so stupid and there are poisons designed to catch you at the middle and long term. Peas have those for example.
Better studying a little botany instead. Euphorbiaceae is a wery widespread family, relatively easy to recognize by its very specialized flowers. All are very poisonous and you can't eat it, but some of them can still be handy. Can provide you wit car tires, torches, fuel, killing your enemies and treatments for diarrhea, expelling worms and, as a nice special bonus, remedy for genital herpes. Yeah, they know what a real survivor needs.
Aren't the main uses for plant poisons/toxins being a defense mechanism for the plant? What evolutionary advantage does killing a predator hours after they killed you have? Seems most "smart" plants would try to be as painful as possible up-front, before they get eaten.
This would work for organisms like us, but plants are organisms structured following a clonal design; can explore other solutions not available to us. And they need also some animal services.
