William Philipps Dunbar (1863 in Minnesota – 1922) was an American physician, director of the State Hygienic Institute in Hamburg, who made seminal discoveries about cholera control and allergies, including identifying the allergen in grass pollen and cat fur.
He developed a regular methodology for monitoring the river and tap water, which was especially significant as this was a primary means for the spread of cholera.
[3][4] Dunbar devised techniques for collecting pure pollen, because sample contamination had previously led to unverifiable results.
He developed methodologies for testing patients' sensitivity to certain pollens by minuscule exposure to pollen via their eyes or nasal passages, By using high-quality lab techniques, he was able to eliminate a number of theories about "hay fever" that were current in the late 1800s.
[1] Much of his work on allergies is summed up in his 1913 publication "The present state of knowledge of hay fever".