[00:00.49]How it came about that snakes manufactured poison is a mystery.
[00:05.10]Over the periods their saliva, a mild, digestive juice like our own,
[00:10.50]was converted into a poison that defies analysis even today.
[00:15.47]It was not forced upon them by the survival competition;
[00:19.07]they could have caught and lived on prey without using poison,
[00:23.08]just as the thousands of non-poisonous snakes still do.
[00:27.29]Poison to a snake is merely a luxury;
[00:30.73]it enables it to get its food with very little effort,
[00:34.40]no more effort than one bite.
[00:37.12]And why only snakes?
[00:39.53]Cats, for instance, would be greatly helped;
[00:42.47]no running fights with large, fierce rats or tussles with grown rabbits
[00:47.51]In fact, it would be an assistance to all carnivores
[00:51.78]though it would be a two-edged weapon when they fought each other.
[00:55.79]But, of the vertebrates, unpredictable Nature selected only snakes (and one lizard).
[01:02.51]One wonders saliva into why Nature, with respect from that of others, as other on the blood.
[01:09.99]In the conversion of saliva into poison, one might suppose that a fixed process took place.
[01:16.51]It did not;
[01:18.01]some snakes manufacture a poison different in every respect from that of others,
[01:23.22]as different as arsenic is from strychnine,
[01:26.77]and having different effects.
[01:28.94]One poison acts on the nerves, the other on the blood.
[01:33.46]The makers of the nerve poison include the mambas and the cobras
[01:38.69]and their venom is called neurotoxic.
[01:42.34]Vipers (adders) and rattlesnakes manufacture the blood poison,
[01:48.17]which is known as haemolytic.
[01:50.70]Both poisons are unpleasant,
[01:53.39]but by far the more unpleasant is the blood poison.
[01:57.53]It is said that the nerve poison is the more primitive of the two,
[02:01.92]that the blood poison is, so to speak, a newer product from an improved formula.
[02:07.80]Be that as it may, the nerve poison does its business with man far more quickly than the blood poison.
[02:15.54]This, however, means nothing.
[02:17.64]Snakes did not acquire their poison for use against man
[02:21.72]but for use against prey such as rats and mice,
[02:25.40]and the effects on these of viperine poison is almost immediate.
