Wolfsbane Dosing (was: Neville/Wolfsbane/Fluffy/Filk/Snape/Time Travel)

[jmwcfo]

No: HPFGUIDX 169477

--- In HPforGrownups at yahoogroups.com, Bart Lidofsky <bartl at ...> wrote:
>
> JW:
> >Continuously boiling the potion might keep it fresh, but the 
> >resultant evaporation of volatile ingredients (as evidenced by the 
> >smoke) would quickly change the proportion of the mixture, 
presumably 
> >rendering it ineffective, or even dangerous.
> 
> Bart:
> You are making an assumption, here, that the volatile ingredients 
have already boiled off, and that the potion is a solution, rather 
than a unified substance that boils off evenly. Or, it could be that 
the only volatile ingredient is water, and that the dosage doesn't 
have to be that exact (although one may speculate that, if one COULD 
control the dosage exactly, it would allow Lupin to actually do 
useful things in wolf form, rather than just resting).  
> Bart
>

JW:
Quite the opposite, Bart.  The volatile and semi-volatile chemicals 
would boil off over extended simmering, and would not necessarily 
effect the first day's dosage.

Please note that the potion is SMOKING.  Smoke is a mixture (as are 
most if not all potions we have seen), not a solution.  Smoke 
comprises a particulate, which is a solid, suspended (mixed, not 
dissolved) in a gas, typically water vapor.  As the boiling 
continues, the proportion of the remaining non-volatized liquid 
mixture is subject to change as volatized ingredients boil off.  
Thus, the second day's potion may have a different proportion of 
ingredients than the first day, raising the issue of possible 
inefficacy.

If the only volatile ingredient were water, you would NOT have SMOKE, 
you would have STEAM, which is water vapor without suspended 
particulates.  Of course, the result would be even WORSE in this 
case.  If the so-called "smoke" were actually steam (water vapor), 
leaving everything else in the cauldron, then over time the remaining 
mixture would thicken into a syrup, goo, sludge, or a caked and 
partially crystallized solid.

For example, try gently simmering salt water (a solution, not a 
mixture, in this case) over an extended period.  You will see steam, 
which is the water vapor that is boiling off. If you test the 
salinity of the remaining liquid, you would see that it consistently 
increases, because the dissolved salt is relatively non-volatile.  As 
the simmering continues, you would observe that the fluid volume 
decreases measurably.  Finally, you would wind up with a dry 
cauldron, errr... pot, with only caked or semicrystaline salt on the 
bottom and sides.

Another illustration of this is growing crystals of salt, sugar, 
alum, and other simple materials at home.  IIRC, this is often 
included in middle-school science courses.  I have also made tiny 
quantities of aspirin (acetylsalicylic acid) in a chemistry lab using 
a similar technique.