In TV series, the ancients liked to test poison with silver needles. Can silver needles really detect toxins?

I'm sorry to tell you that the silver needle can't detect the toxin, or to be precise, the blackening of the silver needle is just a normal discoloration phenomenon formed by chemical reaction with the sulfide contained in the toxin.

The ancient people used silver needles to detect poison, which mostly originated from the book "unjust prison prescription" in the Song Dynasty. "If you take poison, you should wipe it with silver hairpin and saponin water, put it in the throat of the dead, seal it with paper, take it out for a long time, make it blue-black, then wipe it with saponin water, and the color will disappear." If not, its color is bright white. '

This is mainly because in ancient times, arsenic was used to poison people, but in ancient times, due to the limitation of filtration and purification technology, arsenic contained sulfur or sulfide, and the sulfide reacted with silver needle to form a layer of black silver sulfide on the surface of silver needle, so the ancients used silver needle to test the poison. The progress of science and technology in modern society has made arsenic pure. Now arsenic is measured with a silver needle, which will not turn black under normal circumstances.

It is precisely because of the underdevelopment of ancient science and technology that the types of poisons are mostly divided into plant poisons and mineral poisons. Plants, such as Aconitum, Tung oil, Miscanthus, etc. Not easy to collect and purify, with heavy color or smell. Minerals, that is, arsenic-containing minerals such as hemlock red, which are common in film and television dramas, are easy to collect, and the lethal dose is quite low, which can also cause chronic or acute death according to different doses. According to the statistics of ancient literature, about half of the cases of poisoning death in ancient times were caused by arsenic.

So, in ancient times, was there a perfect drug detection tool? I'm telling you, yes, that's a person. In ancient times, the emperor would have someone to test poison for him. These special people are eunuchs who deliver food in the palace. Generally, they are ready to give it a try, and after eating it, there is no adverse reaction before passing it on to the emperor.

So it is true that silver needles are used to detect poison, but it is really impossible to test whether they really contain poison.