In 1920, Joseph Bolivar DeLee published the article, “The Prophylactic Forceps Operation,” in which he describes how physicians can manually remove a neonate from a laboring woman’s vagina with the use of sedating drugs and forceps. The procedure, according to DeLee, resulted in decreased rates of complications and mortality for both the woman and neonate. DeLee claimed the procedure could reduce damage to the woman such as prolapse, or when internal pelvic organs push down and sometimes protrude from the vagina, and fatal infant brain bleeding. He also suggested that physicians make an incision from the woman’s anus to vagina to accommodate the use of forceps, a procedure later known as an episiotomy. In “The Prophylactic Forceps Operation,” DeLee proposed the technique and use of his procedure, adding to the growing debate in the early twentieth century on the best way to medically assist women during delivery.

Emil Kraepelin was a physician who studied people with mental illness in the late nineteenth and early twentieth centuries in modern-day Germany. Kraepelin's examination and description of the symptoms and outcomes of mental illness formed the basis for his classification of psychiatric disorders into two main groups, dementia praecox, now called schizophrenia, and manic-depressive psychosis, now called bipolar disorder. He was one of the first physicians to suggest that those researching mental illness should gain scientific knowledge only through close observation and description. However, Kraepelin also believed that genetics played a role in the development and course of mental illness and characterized mentally ill people as weak-willed, which some have argued contributed to stigma about mental illnesses that persist today. Although some historians have pointed out issues with Kraepelin’s teachings, Kraepelin helped to establish psychiatry as a clinical science, which prompted future experimental investigations into mental illness.