Biology Discoveries

First experimental evidence that individual cells in bone marrow can self-renew and differentiate into multiple blood cell types — the defining properties of stem cells.

Observation that the mould Penicillium notatum produces a substance that kills Staphylococcus bacteria, leading to the first antibiotic.

Isolation of insulin from pancreatic extracts and demonstration that it reverses diabetes symptoms, transforming a fatal disease into a manageable condition.

Identification of the ABO blood group system by demonstrating that serum from one person can agglutinate the red blood cells of another.

Demonstration that inoculation with cowpox material provides immunity against smallpox, establishing the principle of vaccination.