A famous 1935 book called Rats, Lice and History, by bacteriologist Hans Zinsser, expounds on the “intimate role” that lice played in the social life of the human race until well into the 19th century. “It was not so long ago, indeed, that its prevalence extended to the highest orders of society, and was accepted as an inevitable part of existence like baptism, or the smallpox,” he writes.
Some cultures even incorporated the parasite into their traditions, according to Zinsser. The Aztec people collected lice from their bodies in small bags and laid them at the feet of their king. Native people of Northern Siberia threw lice on a visitor in a traditional declaration of love. Zinsser explains this as “a sort of ‘My louse is thy louse’ ceremony.” A Swedish town in the Middle Ages elected a mayor by placing a louse in the middle of a table of eligible candidates, and “The one into whose beard the louse first adventured was the mayor for the ensuing year.”
Later, some Europeans took to shaving their heads and wearing a wig in an effort to deter lice, but the wigs themselves were often full of nits. Nitpicking was a way of life; educated children, however, were taught that it was “improper to take lice or fleas or other vermin by the neck to kill them in company, except in the most intimate circles,” according to Zinsser.