Basal Medium Eagle (BME) is a widely used synthetic basal medium for supporting the growth of many different mammalian cells. BME was originally developed by Harry Eagle for HeLa cells and mouse fibroblasts, when he discovered the minimum requirements for cell growth in vitro. BME has since been used for other human lines, including WI-38 and MRC-5. BME contains eight B vitamins, ten essential amino acids, plus cystine, tyrosine, and glutamine. There are a number of modifications of BME: Minimal Essential Medium, Glasgow's Medium and Dulbecco's Modified Eagle's Medium. This BME formulation contains Earle's salts for use in a CO2 incubator.