produce cortisone, the chemist needs only modify the hydroxyl group in
hydrocortisone using another oxidation reaction. When it was first isolated
from animals, cortisone—which is used to treat ailments such as
rheumatoid arthritis, asthma, and hepatitis—cost about $100 a gram. But
after chemists determined how to make it from the Mexican yam, production
increased, prices dropped, and the drug became widely available.