In To Kill a Mockingbird, what is the testimony of Sheriff Heck Tate about?
In chapter 17 of To Kill a Mockingbird, Sheriff Heck Tate is called as the first witness for the prosecution in the Tom Robinson trial. The sheriff is a witness to the night in question after the alleged crime was committed. This means that he only sees the aftermath of whatever happened, and is not a primary witness to any real crime. Thus, Sheriff Tate's testimony revolves around Bob Ewell fetching him on the night of November 21st, and claiming that a black man had raped his daughter. Like a good officer of the law, Sheriff Tate goes out to the Ewells' home and finds Mayella Ewell on the floor. He notices that she is badly beaten up, so he picks her up, washes her face and asks her who beat her up. She claims that Tom Robinson did it.
Then Atticus Finch gets a chance to cross-examine the sheriff and the first question he asks is if the sheriff called a doctor. Sheriff Tate says he didn't call a doctor. Without a doctor's diagnosis, the only thing Atticus can do is take the sheriff's eye-witness account of the wounds on Mayella's body. After much discussion, it is decided that she was mostly hurt on the right side of her body. Specifically, her right eye was bruised the worst. The sheriff's testimony that Mayella was beaten on the right side of her body is critical to the defense because that means that a left-handed man must have hurt her. Atticus later proves that Tom Robinson couldn't have beaten or raped Mayella because Bob Ewell is left-handed and Tom Robinson's left arm is disabled.