John Marshall Harlan II,
Salem v. United States Lines Company…
“ To me it seems clear that the court referred to expert testimony simply as an example of the kind of evidence that the petitioner might have offered on this score. Consequently, the District Court's charge that the jury could find the respondent negligent 'in failing to provide railings or other safety devices' had injected into the case a theory of liability which had not been presented to the jury by the evidence introduced at the trial. ”
