One morning the bacteriologist is accepted a visitor with a letter of introduction from a friend. The visitor shows curiosity in a live bacterium of cholera. The bacteriologist tells him everything and shows different tubes telling what their contents are. The visitor shows even deeper excitement finding out that there is a living bacteria of cholera in the laboratory.
At that moment, bacteriologist’s wife Minnie calls him out for a minute, and when the bacteriologist returns to the laboratory the visitor is very eager to leave. When the visitor left the bacteriologist finds that the tube has been missed. He immediately runs after him and gets into a cab to get the visitor. Minnie watches her husband running along the street through the window. He is hatless and one of his slippers is took off. She says he is mad but it is her duty to help so she takes a hat and hires a cab to run after her husband. On the streets of London a real chase is formed, people amuse themselves watching it and commenting.
The visitor sitting in the cab is dreaming of how he will poison the river and kill most of the people; he wants to become famous and thinks it is the best way to make people talk about him. but the tube breaks and its contents is poured on him. he tell the cabman to stop and get off the cab. At the very moment the bacteriologists catches up.
The visitor calmly walk along the street with a thought to get to the first well and wash his hands so the poison would get into the water. But he does not know that the bacteriologist at the first sight had guessed that the visitor was anarchist and ran after him only to make himself sure. And in the tube there was no bacterium of cholera but a bacterium which provokes blue stains in monkeys.
