GREGORY PETSKO: For thousands of years, long before there was such a thing as a science of chemistry, people were fascinated by plants, because they knew that plants contained substances that could affect people. Coffee will keep you awake. Tobacco contains something that will calm your nerves. Foxglove contains an extract that'll affect your heart. And the whole goal of chemistry in the early part of the 20th century was to understand what these natural products were, to characterize their chemical structures, and figure out how to make them. This was called "natural products chemistry." It was the main branch of chemistry. And in 1929, Vienna, in Austria, was the seat of natural products chemistry. And that's why Percy Julian went there.
Hives are usually an allergic reaction to food, medicine, or animals. They can also be triggered by sun exposure, stress, excessive perspiration, or other, more serious diseases, such as lupus. Anyone can get hives. They are harmless and non-contagious. Hives may itch, burn, or sting. They rarely need medical attention as they tend to disappear on their own. However, in persistent cases, your dermatologist may prescribe antihistamines or oral corticosteroids. The best way to prevent hives is to discontinue exposure to the allergic irritant.