The Second Book of General Ignorance

There are various accounts of humans growing ‘horns’ of the non-bony type. One of the strangest concerns Anna Schimper, ‘the horned nun of Filzen’. In 1795 her nunnery in the Rhineland was occupied by French troops and the nuns evicted. The shock sent Anna mad and she was committed to an asylum. After years spent banging her head against a table, a horn started to grow from the bump on her forehead. The more it grew, the less deranged she became until she was soon sane enough to return to the nunnery, where she became abbess.
By 1834 her horn had grown to such a length that it was hard to conceal under her wimple, so she decided to have it removed. Although she was eighty-seven and the operation was both bloody and painful, she survived and lived for two more years. By the time she died her mysterious therapeutic horn had started to grow again.

The polar food chain is based on marine algae that are rich in vitamin A. The further up the chain you go, the more it concentrates. Huskies – like seals and polar bears – have evolved to cope with it. Humans haven’t. There is enough Vitamin A in just 100 g (3½ ounces) of husky liver to kill a grown man.

True horns have a permanent bone core surrounded by compacted strands of a protein called keratin – the same stuff that human hair and nails are made from. Animals that have them include cattle, buffalo, sheep, antelopes and horned lizards.