In Daniel Keyes's Flowers for Algernon, Charlie makes a mental connection between Algernon's erratic behavior and his own fate while at the conference in Chicago, detailed in "Progress Report 13."
During the conference, Charlie realizes that Professor Nemur had made a mistake in his calculations. Nemur had known that there would be a waiting period to see if Charlie's intelligence remained permanently steady or diminished; however, Nemur had calculated the waiting period based on the waiting periods of "normally dull or normally intelligent animals." Charlie knew Nemur hadn't realized that the waiting period would need to be increased if the animal's "intelligence had been increased two or three times." Charlie then realizes that Algernon's erratic behavior was a sign that his intelligence was diminishing and that that would be his fate as well. It is at this moment of realization that Charlie most feels like a dehumanized science experiment. It is hearing Nemur refer to their work as having transformed Charlie from "a burden on society" into a superhuman being coupled with the understanding that their experiment failed which makes Charlie feel the most dehumanized.