What is wrapped in tissue on Myrtle's bureau in The Great Gatsby?
George Wilson finds an expensive-looking dog leash wrapped in a piece of tissue hidden in Myrtle's bureau. As the item must have cost a fortune, and as the Wilsons don't have a dog, George rightly concludes that Myrtle's been cheating on him. His discovery of the dog leash leads to a blazing row, which ends with George locking Myrtle in her room. After Myrtle's tragic death, George gets the wrong end of the stick—thanks largely to Tom's shameless lies—and thinks that Gatsby was responsible for running Myrtle down. But he seems blissfully unaware of his late wife's affair with Tom Buchanan.
The dog leash is just one of many imaginative symbols in The Great Gatsby. It perfectly represents the relationship between Myrtle and Tom. Tom never once accepted Myrtle as his equal; as far as he was concerned, she was just another notch on his bedpost, a convenient plaything with which to wile away the hours. Myrtle was Tom's pet, and metaphorically speaking, he always kept her on a tight leash.
If we cast our minds back to that notorious little gathering at Tom's bolt-hole one scorching hot afternoon in New York, we can recall Tom's casually vicious assault on Myrtle when she started putting on airs and graces. This was Tom's none-too-subtle way of reminding Myrtle that she was his social inferior, and as such had no right even to mention Daisy's name in his presence. The dog leash, like the illicit relationship between Tom and Myrtle, is an expensive extravagance, but ultimately of no intrinsic worth or lasting value.
George is distraught over his wife's death. In Chapter VIII, Michaelis finds "a small expensive dog leash made of leather and braided silver...apparently new" in a dresser drawer. The Wilsons did not have a dog, but Myrtle did cajole Tom into getting her a one to be kept at the apartment they used for their illicit meetings back in Chapter II. George says he found the leash the day before, "wrapped in tissue paper on Myrtle's bureau", and the discovery rightly confirmed his suspicions that Myrtle was having an affair. He recalls that he spoke to her about it, telling her "God knows what you've been doing, everything you've been doing. You may fool me but you can't fool God!"
George believes that Myrtle's unknown lover is the one who was riding in the car that killed her. He concludes that if he can trace the car to its owner, he will be able to determine his rival's identity.