I have had adog bit by a copper head on his back leg, leg was 4 times it's normal size un under 20 min. We rushed him to the vet on Sunday afternoon. The vet told us with him that the big concern is infection, that snake mouths are filled with all kinds of nasty stuff. But a day int he Hospital and 10 days on antibotic he was back to normal.
Then had another dog (really more of a pup) stung by a wasp or bee on the nose which then started to swell to twice the normal size. Rush him to the vet on Sunday (our vet loves our dogs!) he just needed some benadryl over two or three days then was back hunting.
From what our vet has told us it is more important to watch for individual dog reaction to bite or sting. There are some dogs that will really react (must be all mine) and some that barley react.
I have heard of the electric shock on snake bites, there was an artical on it in one of my magazines. They said that research did not show that the shock helped prevent reaction in any way, and in many cases increased reaction becaused it caused the animal to panic raising it's heart rate and increasing circulation. The better action is to keep the dog or person very calm and get them to a medical facility. I know there are a lot of you out there that will not go to a vet especailly on Sunday. Generally there is a 40 dollar after hour fee, so ask youself this is this dog worth saving? sometimes the answer is no. Sometimes it is yes.
BUT PLEASE DO NOT MESS AROUND IF IT IS A HUMAN GET THEM TO A DOCTOR!!!

I work to support my beagle habit.