During the mid-twentieth century, Virginia Apgar worked as an obstetrical anesthesiologist and gave drugs to women that reduced their pain during childbirth in the US. In 1953, Apgar created a scoring system, called the Apgar score, that uses five measurements, including heart rate and breathing rate. The Apgar score evaluates newborn infants and determines who needs immediate medical attention. Apgar's work helped decrease infant mortality rates. As of 2020, hospitals around the world use the Apgar score.

Johann Gregor Mendel studied patterns of trait inheritance in plants during the nineteenth century. Mendel, an Augustinian monk, conducted experiments on pea plants at St. Thomas’ Abbey in what is now Brno, Czech Republic. Twentieth century scientists used Mendel’s recorded observations to create theories about genetics.

Katsuma Dan reflects on his first meeting with Dr. Victor Heilbrunn at the University of Pennsylvania in December 1930. Recorded at the University of Washington, Friday Harbor group in 1978.

By the 1930s, the MBL had become "the" place to go during the summer for biological research and training. Luminaries such as Frank Lillie, Edmund Beecher Wilson, Edwin Grant Conklin, and Thomas Hunt Morgan took their students, packed up their families and research labs, and headed to the MBL. They worked in labs, ate together in the Mess, and they often lived in the limited on-campus housing. Life at the MBL was a life where fun, family, and science intertwined. This film, taken in 1935 by B. R. Coonfield of Brooklyn College, captures snippets of life at the MBL.

Gertrude Belle Elion was a twentieth-century scientist in the US who researched the structure of viral DNA to help develop anti-viral medications. For her work on drug development, Elion was a co-recipient of the 1988 Nobel Prize in Physiology or Medicine, even though she lacked a PhD or MD. In the 1970s, Elion helped to develop acyclovir, an early anti-viral medication, alongside a team of other researchers. Acyclovir was one of the first selective medications to effectively treat herpes simplex virus types 1 and 2, or HSV-1 and HSV-2. Those are common viruses that can be transmitted via close contact or sexual intercourse, and cause sores on the mouth and genitals. The medications that Elion helped develop were also some of the first to specifically inhibit the replication of viral DNA. By creating medications like acyclovir based on her knowledge of chemistry and biology, rather than through trial and error, Elion helped create a new model for drug development, in addition to making an effective treatment for herpes, which afflicts billions of people globally, and can cause life-threatening illness in infants.