According to Merriam-Webster, a poison is a substance that through its chemical action usually kills, injures, or impairs an organism.
As Paracelsus, a German-Swiss physician and alchemist who established the role chemistry plays in medicine, is supposed to have said 500 years ago, “All things are poison, and nothing is without poison: the dose alone makes a thing not poison.”
What he said is true. We are surrounded by potentially deadly substances, a lot of which have therapeutic uses. Yet take too much and they can kill (so successfully, a number have become favourites with murderers).
Of course, we’re surrounded by potential poisons, so why isn’t everyone dying?
Because our bodies are designed to protect us from both natural and man-made toxins. The first line of defense, skin, is made of keratin—so waterproof, tough, and tightly woven that only the smallest and most fat-soluble molecules can get through. Our senses warn us of noxious substances; if they fail there is vomiting as backup. Finally, there is the liver, which turns fat-soluble poisons into water-soluble wastes that can be flushed out through our kidneys. The balance tilts over to toxicity only when we step over the threshold of dosage.From: National Geographic
Over the next month of A to Z-ing I will be looking at a variety of poisons – common and not-so-common – and the untimely deaths attributed to them.
A to Z starts tomorrow. Come back to learn about a poison that was a favourite in fiction as well as real life. Can you guess what it is?