Date of Award


Document Type

Undergraduate Honors Thesis

Degree Name

Bachelor of Arts (BA)



Advisor/Committee Chair

Richard Hamm, Ph.D.

Committee Member

Michitake Aso, Ph. D.


The acquittal of Mary Harris in 1865 demonstrates the culmination of new social and scientific ideologies through the strategy of her defense counsel and the utilization of expert medical witnesses. While at the same time, the prosecutorial strategy embodied the opinions of gender and insanity that were being phased out.

The aim of this project is to demonstrate the overlap and reciprocal influence of science, law, and society, with narratives of gender acting as consistent undertones in these three realms. The trial and acquittal seem to fall in line with the idea that the insanity plea is a sham — a tool to permit socially disapproved behavior.However, analysis of the case reveals the use of relevant popular science to support Harris’s insanity. The jury may have been inclined to acquit given the social context and sore heartstrings, yet I argue that the influence of the science of phrenology and the use of expert witnesses presented in litigation swayed the jury against the prosecution’s pressure to appeal to the established laws on murder and insanity. The access the jury had to this knowledge of science set their verdict apart from the opinion pushed by the media following the trial.

The separation of popular science from the interpretation of insanity cases leaves scholarship with a partial view of how medical jurisprudence in the nineteenth century truly functioned. And the arguments of defense teams are often reduced to the influence of social narratives rather than the presence of gender bias in science. The Harris case is unique in that it captures a moment in history where a woman in her situation was aptly proven to be not guilty of murder, and her defense argued well enough to see her acquitted on account of either sympathy or insanity.