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.[5] Dunbar determined that it was the dried cat saliva on cat hair that caused the allergic reaction. With regard to grass pollen, Dunbar identified the albumin fraction as the active toxin, discovered changes in the blood that accompanied exposure to the pollen, and was able to grade individual's relative susceptibility to each type of pollen.[1] Much of his work on allergies is summed up in his 1913 publication "The present state of knowledge of hay fever".[6]