Excerpt:
...Dating from July 27, 1948 to June 19, 1949, some of the slides are numbered in ink on red store style price tags, 7 through 33. The numbering is not sequential with the dates on the slides, which suggest that more than one set of slides were developed. Although the exact origin of the slides is unknown, it is possible that they come from a nearby state psychiatric hospital, which was administering electroshock therapy.

The slides appear to be a partial visual record of progress through such a course of electroshock treatment. Electroshock Therapy (EST), also called electroconvulsive therapy, is a term used to describe introducing a seizure by administrating a jolt of electricity through the brain.