Ttyjukl

While reading Sorcerer's Stone, I just finished the chapter where Harry walks in on Snape and Filch bandaging Snape's leg. In a previous chapter Neville falls off of his broom and we see that magic can easily heal his broken wrist. If magic can heal an injury like broken bones, why wouldn't Snape heal his leg, which was just torn up by a 3-headed dog?

My initial thought was that only certain people specialize in healing magic, but while poking around this site I came across this question: Could George's ear have been healed by Snape? This shows that Snape had at least some healing abilities. So why didn't he heal his own leg? Are there limitations that prevented Snape from healing his own wounds?

Based on the wide range of injuries shown the books, it looks as though mundane injuries are easy to heal, but injuries inflicted by magic (or highly powerful magical creatures) are more difficult and can leave permanent reminders of their presence. Neville's broken wrist was the kind of thing that could happen to Muggles, thus was easy to fix off-screen. Bill Weasley's werewolf wounds and Alastor Moody's injuries by Death Eaters, on the other hand, left permanent disfigurations.

There appears to be a correlation between the power and 'Darkness' of the magic inflicting the injury, and the difficulty of treating it. In the early books, and when students are cursing each other, the injuries are usually easily cured, as in the case of Gregory Goyle's boils and Hermione's outgrown teeth (in HPGOF). Later, we see injuries that are permanent and disfiguring, as the power of the magic used against protagonists increases in deadliness. Draco's Sectumsempra maiming by Harry Potter is an intermediate case, as it was a malific spell but was cast without understanding or deadly intent.

The bites from Fluffy, though from a magical creature, were probably healed with reasonable ease once Snape got treatment. George's ear, being removed by a powerful and malific Sectumsempra spell by Snape, would be much more difficult to heal. Snape himself, possessing some healing spells and great power, may have been able to do so (especially as he had been the one who created the spell). This is supported by the fact that he helped to heal Draco's Sectumsempra injuries in such a way as to leave him without mentionable scars. However, it is likely that he would only have been able to do so if George had kept his ear available for quick reattachment, as (again from Moody) we see that amputations appear to be permanent.

(edit) Upon reading the sources above, it seems that a body part severed by any kind of Dark magic is unrecoverable. But this raises another interesting point. The books have implied that Dark magic's power and presence, to some degree, depends on the malice of the wielder. A Crucio curse by Potter against Bellatrix Lestrange, for instance, is easily shrugged off, whereas her own Crucio is agonizing. We know that Snape willingly casts Dark spells, as when he used Avada Kedavra against Dumbledore...but the truth of his intent may not have been malicious enough to cause the full aftereffects of a Dark spell. The spell itself was Dark, however, and that may be enough for the amputation to be permanent, if only a trace is needed.

According to the Potter wiki, these are some of the abilities of healing magic:

• Reversion of problems as a result of using animal hair in a Polyjuice potion


• Regrowing of bones (Skelegrow)


• Cure for common cold (Pepperup Potion)


• Clearing of a blocked throat e.g. in a choking situation (incantation Anapeno)


• Mending of broken bones (possibly incantation Brackium Emendo - whether this is legitimate or not we don't know; trust Lockhart to stuff it up!)


• Healing of minor wounds like a split lip or broken nose (incantation Episkey)


• Bandaging and splinting of broken bones, as well as pain relief for the said injury (incantation Ferula)


• Counter curses for some curses which cause injury. One such example is the incantation Vulnera Sanetur which is also a general healing spell it seems


• Wound cleaning potions


• Burn-healing potions


• Cures for acne (Bubotuber pus)


• Restoration from those transfigured or cursed (Mandrake Restoration Draught)


• Blood replenishing potion


• Sleeping potion


• Healing of cuts and abrasions (Murtlap Essence)


• Poison antidotes


• Awakening one from a magically-induced sleep (Wiggenweld Potion)


• Calming potions for those suffering from shock, emotional outbursts or trauma (Calming Draught)


• Restorative effect after being in the presence of dementors (chocolate)

So, if we look through that list we see that Healing magic is quite great. However, you will note the absence of the following:

• Optometry - notice how Harry still has to wear glasses


• 
  Mental health - no mention of a magic healing spell for that!


• Also recall there people simply don't leave from St Mungo's Hospital for Magical Maladies and Injuries, I'm particularly thinking of those who have lost their minds from whatever cause. Amongst those are the Longbottoms from torturing, as well as Lockhart after he lost his memory.


• Chronic diseases are not mentioned at all! We don't know how effective healing magic is at curing those

So, Healing magic does have some limitations. The above is by no means an exhaustive list, but I've tried to provide more of general areas where healing magic appears to have its limitations.