Dr. John Ross:

The only medical fact known about Shakespeare with certainty is that his final signatures show a marked tremor. Compared to other Elizabethans, Shakespeare had an unhealthy obsession with syphilis. D. H. Lawrence wrote, “I am convinced that some of Shakespeare’s horror and despair, in his tragedies, arose from the shock of his consciousness of syphilis.”

According to contemporary gossip, Shakespeare was not only notoriously promiscuous, but was also part of a love triangle in which all three parties contracted venereal disease. The standard Elizabethan treatment for syphilis was mercury; as the saying goes, “a night with Venus, a lifetime with Mercury.” Mercury’s more alarming adverse effects include drooling, gum disease, personality changes, and tremor. (In the eighteenth century, mercury was used in the manufacture of felt hats, leading to the expressions “hatter’s shakes” and “mad as a hatter”). Did Shakespeare’s writing career end prematurely due to side effects of mercury treatment?

Milton, the Bronte sisters, Melville, Yeats, Joyce and Orwell — How disease may have infected your favorite books