New Skills: Healing, Appraisal, Persuasion

While I'm procrastinating an already late term paper, I thought I'd throw out a couple more candidate house rules.  I'm sure someone has done something similar; I'm sure I saw another Healing/Heal/Chirurgy/etc. skill.

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APPRAISAL

Upon a successful skill roll, the character can gauge the approximate value of an item.  The Referee need not specify the exact value, but at least the order of magnitude should be right.  This skill cannot take into account invisible or undetectable properties of an item, like magic or historical significance.

HEALING

This skill represents mundane healing arts.  It has three uses:

1. Binding Wounds: After a battle, a character may use this skill on himself or another to regain a number of hit points equal to the value of the die roll, or half the number of hit points lost during the battle, whichever is smaller.

2. First Aid: If a character has gone below 0 HP (but not lower than -3 HP) in the previous round, a successful Healing roll gives the character a second chance.  The dying character may make a Save vs. Death to stabilize, with a penalty equal to the number of hit points below 0.  If that saving roll succeeds, the character's hit points reset to 0.  First Aid can also save the life of a character dying from poison, drowning, or other familiar and natural causes.

3. Long-Term Care: If a character with the Healing skill attends a wounded character in clean, safe surroundings with easy access to medical supplies, multiply the wounded character's healing rate by the healer's Healing skill value.  A healer can attend multiple characters, although each additional patient reduces the multiplier by one.

PERSUASION

If a character has a chance to talk to NPCs for several minutes and knows the NPCs' language, he can test his Persuasion skill.  If the skill test succeeds, the NPC's reaction roll increases by 1d3.  The Referee may increase a character's effective Persuasion skill if the PLAYER provides a convincing or at least entertaining performance.  This skill cannot be used against an NPC who is already attacking.

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Healing seems like an essential skill if the party has no Cleric, but I worry it's a bit overpowered and overloaded.  If someone can point me at other versions, I'd appreciate it.

I'd also like to do something like Knowledge or Lore skills, but they could proliferate outrageously.  Perhaps a single Education skill would suffice.  If successful, the player could know an obscure but pertinent fact, discover a clue, or make a Cliff-Clavin-esque pronouncement about the game world and have it actually be true (subject to Referee approval).  "Oh, yes, this is clearly a van Ooms masterpiece from his mauve period."

Alternatively, the Education skill might represent the number of times a character can show off his erudition in this way, a la Investigative Skills in the GUMSHOE system.  If a character spends that last point, maybe anything he thinks he knows about the game world can be wrong, retroactively.  "Cat?  What's a cat?"