History Of Allergy

In 1902, two French scientists injected dogs with a small amount of extract from the sea anemone. Nothing happened. A week later, they repeated the procedure in exactly the same way - and watched, amazed, as the animals developed severe reactions.

The dogs had somehow become sensitive to the formerly harmless substance. The researchers had discovered anaphylaxis, an extreme form of allergy.

In the decades since that landmark series of experiments, researchers have found that cells and molecules that exists to protect us from harm may paradoxically cause heightened response to everyday allergens.