Why do dock leaves relieve nettle stings so effectively?
The stinging nettle causes the discomfort so familiar to curious children and errant walkers by distributing a mixture of three chemicals when the delicate hairs on the leaves are broken by contact with the skin. The broadly acidic chemicals are countered by an alkali in the leaves of the broad-leafed dock, Rumex obtusifolia, which is released when the leaves are crushed and placed against the skin. Their effectiveness is none the less questionable, with some suggesting any comfort is more likely to be derived from the coolness of the leaf on irritated skin and their abundance close to nettle clumps. How many species live on or in the human body? The short answer is about 200, including 80 in the mouth alone. But that is to belie the sheer industry of the microbial entrepreneurs that inhabit our beings. The total number of bacteria excreted by the body every day ranges from 100 billion to 100 trillion. Every square centimetre of human bowel is home to around 10 billion microbes. Some 1
