What do Tom do to Myrtle (physically), which injured her? Why did Tom do this?

At a party in their apartment, Myrtle keeps saying the name "Daisy" over and over. Tom hits Myrtle across the face, breaking her nose. This is the second time that Tom's penchant for hurting women is very real. When Nick first meet Daisy, she is complaining that Tom is a "brute" and he hurt her little finger. However, the incident was only alluded to by Daisy. In Chapter Two, Tom's explosive anger is actually revealed as Nick and the others in the apartment see him hit Myrtle in order to stop her taunting.

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