How large is a dose?

[Anaraxes]

Originally Posted by scc

they never entered common use before the metric system

Depends on what you mean by "common use", I suppose. Systems like apothecary's measures were in quite common use throughout Europe among the people that needed to measure small amounts of things -- in this case, apothecaries and other people dealing with drugs.

The main reason people invented such small units, mostly inherited from the Romans, was to avoid dealing with fractions. Modern fractions didn't even exist in Europe until the 17th century, and doing math with Egyptian fractions is a bit painful. Fractions of a pound become important come up when you're weighing valuable or potent things that are lighter than pounds and ounces, so you start using drams and scruples and grains.

Carats, for gems and often gold, go back at least to the 1400s in England. The Romans had a unit called the solidus, also a gold coin, which was 1/72th of a pound. It was divided into siliquae, 1/24th of a solidus. The carat in gold purity ("24 carat gold"), we still use today is that same unit, 1/24th of a solidus.

The average peasant-in-the-field might not have cared about small measurements, but they certain existed and were widely used by those professions and merchants that needed them long before the metric system.

[vicky_molokh]

Originally Posted by malloyd

But is unfortunately how poisons are. Assuming they killed you on a failed HT roll, a "dose" would presumably be about the LD50 dose for an average human, which can vary wildly - i.e. its about 900 grams of salt, 600 grams of ethanol, 60 grams of nightshade berries, 15 grams for caffeine, 7 grams of cocaine, 1.2 grams arsenic trioxide, 0.5 grams of sodium cyanide, 0.2 grams of castor beans, 1.8 milligrams of ricin, 1 microgram of botox....

For low TL natural extracts 10 grams or milliliters isn't an unreasonable value for "good" poisons though.

In GURPS, a dose isn't the LD50 dose. Rather, it's a dose which can be delivered by a poison blade or a specialized poison bullet. Thus, various poisons have differing HT modifiers and/or damage values.

[Varyon]

Originally Posted by malloyd

900 grams of salt, 600 grams of ethanol, 60 grams of nightshade berries, 15 grams for caffeine, 7 grams of cocaine, 1.2 grams arsenic trioxide, 0.5 grams of sodium cyanide, 0.2 grams of castor beans, 1.8 milligrams of ricin, 1 microgram of botox....

Add some water and chug it down for one hell of a rush.


For acid, Dungeon Fantasy has enough to cause 1d-3 corr weigh 0.5 lb, for about a cup (half a pint) of volume. Add in the small bottle it comes in for the full pound listed. Poison is stated to have negligible weight once you've smeared it on a weapon, but otherwise weighs 0.25 lb, for about 4 oz (half a cup); presumably, there's a lot of wastage involved (there's also a good deal of abstraction going on, as you use the same amount to poison the tip of a dart as to poison the blade of an SM+1 greatsword).

[malloyd]

Originally Posted by vicky_molokh

In GURPS, a dose isn't the LD50 dose. Rather, it's a dose which can be delivered by a poison blade or a specialized poison bullet. Thus, various poisons have differing HT modifiers and/or damage values.

Realistically it won't vary a lot for that. Most poisons don't separate "no significant effect" from "certain death" by much more than a factor of 10 (with LD50 being somewhere in between).

But RPG and fictional poisons are light on realism anyway. If you held to that too strictly it might well mean there are zero poisons that can provide a "dose" for purposes of affecting human targets before the advent of TL5 chemistry. Which may well be true, reality is pretty short of examples of successful blade poisons. Of course people stabbed with a poison blade tend to bleed, which washes the poison *out* rather than in and is likely to kill you from blood loss long before a poison would do anything anyway.

[vicky_molokh]

Originally Posted by malloyd

Realistically it won't vary a lot for that. Most poisons don't separate "no significant effect" from "certain death" by much more than a factor of 10 (with LD50 being somewhere in between).

But RPG and fictional poisons are light on realism anyway. If you held to that too strictly it might well mean there are zero poisons that can provide a "dose" for purposes of affecting human targets before the advent of TL5 chemistry. Which may well be true, reality is pretty short of examples of successful blade poisons. Of course people stabbed with a poison blade tend to bleed, which washes the poison *out* rather than in and is likely to kill you from blood loss long before a poison would do anything anyway.

You just posted a list of comparisons where LD50 ranged from micrograms to a pound and then some, and you're saying that it won't vary a lot? Also, I thought stuff like the dart frog poison is TL0.

[Anaraxes]

Originally Posted by vicky_molokh

You just posted a list of comparisons where LD50 ranged from micrograms to a pound and then some, and you're saying that it won't vary a lot?

No; he's saying that for a given substance, the difference between the LD10 and the LD90 isn't usually a lot. Or to quote: "separate 'no significant effect' from 'certain death'", since there's a difference between "no significant effect" and "not dead".

[vicky_molokh]

Originally Posted by Anaraxes

No; he's saying that for a given substance, the difference between the LD10 and the LD90 isn't usually a lot. Or to quote: "separate 'no significant effect' from 'certain death'", since there's a difference between "no significant effect" and "not dead".

Ah. Well, 10 doses of a poison is serious business in GURPS for the more serious poisons. E.g. a single dose of cyanide is around 2d, which is not even LD50. But 20d? That's almost a sure kill.

[Bruno]

I'm pretty sure putting multiple doses of poison on a blade gives a penalty on HT rolls, not stacking damage. At least in "normal" GURPS - Dungeon Fantasy poisons are excused because they explicitly are meant to act the way people think poison works, not the way biology actually works. (EDIT: page 439, Varying the Dosage)

There are a LOT of mentions of the word "Poison" in the basic set, my god.

First Aid also lists "sucking out poison", which is nonsense First Aid at best, or bad for the patient and first aider at worst.

[Bruno]

Relevant to the original question:

Originally Posted by Basic Set page 437

DESCRIBING
POISONS
A poison’s description includes its
name, means of delivery, delay, resist-
ance roll, effects (injury and symp-
toms), and cost per dose – and possi-
bly notes on what constitutes a
“dose,” how to use or conceal the poi-
son, and how to treat it (including any
antidotes).

Emphasis mine. It's definitely intended to vary from poison to poison.


EDIT: also, page 437, SPECIAL DELIVERY box, Cumulative, has notes about stacking multiple doses, but they boil down to "you can do different stuff with multiple doses of poison, and you might want to look at what you define as a 'dose' anyways".

[whswhs]

Originally Posted by vicky_molokh

You just posted a list of comparisons where LD50 ranged from micrograms to a pound and then some, and you're saying that it won't vary a lot? Also, I thought stuff like the dart frog poison is TL0.

Note that the two that are over a pound are ethanol and sodium chloride. Neither of those is normally called a "poison." That's not to say that they can't have toxic effects—but that the common encounters are with smaller doses that human beings consume for nutrition and/or enjoyment. Then there are substances that would usually be classed as "drugs." Nearly all of them have an LD50 (or an LC50 for gases; for example, it doesn't take that much more oxygen than the usual concentration to start having unpleasant effects). But if you want to poison someone, you're not going to dose them with table salt, and probably not with ethanol, but with something that's toxic in very small amounts.

(Steven Boyett's novel The Architect of Sleep has a passage about a pet raccoon that figured out how to pry off a childproof cap and ate an entire bottle of Vivarin. Now that's a fairly horrifying death! But if you fed an adult several grams of caffeine they'd almost certainly notice it.)