First, let's clear up any confusion about the words snake, asp, and viper. Snake is both the oldest and the most inclusive of the three terms: as long as English has been around, snake has been used to refer to any of numerous limbless scaled reptiles. Asp names a small venomous snake of Egypt usually held to be a cobra. Many of us associate the asp with the suicide of Cleopatra, and favored criminals in ancient Greek and Rome were executed by its bite.

Viper refers to any of a variety of venomous (but not usually fatal to humans) snakes. That name has its origin in an old belief that vipers were viviparous--that is, they produced living offspring, not eggs. Both snake and viper are applied to treacherous humans too.

Many folks are frightened of snakes, but snakebites are neither all that common nor necessarily fatal. Ophiologists (that is, snake experts) estimate that of the several thousand poisonous snake bites that occur each year in the U.S, only about 15 result in death. Many of those deaths probably befall practitioners of ophiolatry, or snake worship.

Hey, gillyh! As you seem to have knowledge on such things, where did the term "snake oil" come from, as a reference to a silver(fork-tongued?) salesman of potions? Do you know? I always wondered that. I just thought I'd asp!

Viper is another name for the British Adder, our only poisonous snake. They classically have a diamond pattern along the top of their bodies. People usually get bitten when they walk in long grass not aware that the snake is there, therefore, startling the snake, which will then defend itself. The adder is quite shy, bites are usually accidental

Personally, I feel too many people get the wrong idea of snakes. They seem to believe they are slimy creatures, when in actual fact they are not. They also believe all snakes bite, and they will die if bitten, again untrue. Ok, maybe if you are bitten by a black mamba, a cobra or a rattlesnake, and are far from medical help, you will likely die. Or maybe you would be asphixiated if a 50 foot anaconda wound itself around your neck. But how likely is that?
Having owned an Indian python, I have to say, they are very gentle and friendly and don't mind being handled at all. These make excellent pets, and are easy to look after, as long as you remember they are coldblooded creatures and need a little warmth.

Lefois, I think in the l800's salesmen went about pitching their product which was "snake oil" in a bottle, guaranteed to save the user's life in the event of snake bite. They even carried around defanged venomous snakes to show how their product worked and the gullible folks would buy it and keep it on their shelves for such an emergency. It was a con game.