Snake poison

How it came about that snakes manufactured poison is a mystery. Over the periods their saliva, a mild, digestive juice like our own, was converted into a poison that defies analysis even today. It was not forced upon them by the survival competition; they could have caught and lived on prey without using poison, just as the thousands of non-poisonous snakes still do. Poison to a snake is merely a luxury; it enables it to get its food with very little effort, no more effort than one bite. And why only snakes? Cats, for instance, would be greatly helped; no running fights with large, fierce rats or tussles with grown chickens - the mouse or young chicken goes limply into the cat's mouth.

The snakes' poison is highly modified saliva containing zootoxins which act on the nervous system and blood circulation. It is different in every single kind of snake - from the cobra's for instance which affects the nerves, to the viper's which, on the contrary, affects the blood.

One wonders also why nature, with some snakes, concocted poison of such extreme potency. In the conversion of saliva into poison, one might suppose that a fixed process took place. It did not; some snakes manufactured a poison different in every respect from that of others, as different as arsenic is from strychnine, and having different effects. One poison acts on the nerves, the other on the blood.

The spitting cobra is another case of a snake that has modified its saliva into a poison different in nature from that of other snakes. This snake, instead of biting, spits out a jet of venom which may reach a distance of two feet. It is not very accurate, but it is enough to cause a lot of pain and some blindness if it gets into the eyes. The spitting cobra has little poison. What is this snake's advantage in having a poison that is not very powerful? The answer is that it has a very good aim; it is almost always successful in hitting its target, which is the eyes of the victim. And why should it spit? There is no obvious reason why it should not bite. The answer is that it has a good aim; it is almost always successful in hitting its target, which is the eyes of the victim. By spitting, it can keep a safe distance from its prey, which is a great advantage in a fight.

蛇是怎样产生毒液的，这是一个谜。蛇的唾液本来和我们人的消化液一样柔和，经过漫长的时间，演变成了今天仍无法分析清楚的毒液。毒液不是生存竞争强加给它们的，它们可以不用毒液捕捉动物而生存，就像今天成千上万的无毒蛇那样。毒液对蛇来说只不过是一种奢侈品，它使蛇可以毫不费力地获取食物，轻咬一口即可。为什么只有蛇才有毒液呢？如果猫有毒液，那对猫会大有帮助，它就不必再和又大又凶的老鼠边跑边搏斗了，也不必再和大鸡扭斗了，只要咬一口，老鼠或小鸡就会瘫软下来成为猫的口中物。

蛇的毒液是高度进化的唾液，含有动物毒素，作用于神经系统和血液循环。不同种类的蛇的毒液各不相同，例如眼镜蛇的毒液作用于神经，而蝰蛇的毒液则相反，作用于血液。

人们还会感到奇怪，为什么大自然在某些蛇身上调制出如此高效的毒液呢？在把唾液转化为毒液时，人们可能认为会有一个固定的程序。事实并非如此，有些蛇产生的毒液在各个方面都与其他蛇的毒液不同，就像砒霜不同于马钱子碱一样，它们产生的效果也不同。一种毒液作用于神经，另一种毒液作用于血液。

喷射毒液的眼镜蛇又是一个例子，这种蛇把自己的唾液转化为一种性质与其他蛇的毒液不同的毒液。这种蛇不是咬，而是喷射出一股毒液，射程可达两英尺。毒液喷射得不是很准，但如果射进眼睛里，就足以造成剧痛，甚至失明。喷射毒液的眼镜蛇毒液量很少。这种蛇的毒液威力不大，它的优势是什么呢？答案是它的喷射非常精准，几乎每次都能射中目标，也就是受害者的眼睛。那么它为什么要喷射毒液呢？没有明显的理由表明它不应该咬。答案是它的喷射非常精准，几乎每次都能射中目标，也就是受害者的眼睛。通过喷射毒液，它可以与猎物保持安全距离，这在战斗中是一个很大的优势。