What discovery did Howard Florey and Ernst Boris Chain contribute to during World War II?

Howard Florey and Ernst Boris Chain played a crucial role in the mass production of penicillin during World War II. Their work followed the initial discovery of penicillin by Alexander Fleming. While Fleming had identified penicillin's antibacterial properties, it was Florey and Chain who developed methods to produce it in large quantities, making it widely available for use in treating infections among soldiers and civilians alike.

Their research demonstrated how penicillin could be extracted and produced efficiently, addressing the urgent need for effective treatments during the war when bacterial infections were common and often fatal. This breakthrough not only transformed the treatment of infections at that time but also laid the foundation for the antibiotic era that followed, significantly impacting medicine.

The other options involve important medical developments but are not related to Florey and Chain's contributions. Morphine, vaccines, and antiseptics were established areas of treatment prior to their work with penicillin and did not involve the same transformative mass production efforts they undertook with antibiotics.