In 2005, J. Robin Warren and Barry J. Marshall shared the Nobel Prize in Medicine for discovery of the bacterium Helicobacter pylori, and for establishing experimental proof that it plays a major role in gastritis and peptic ulcer disease. The story began when Warren, a pathologist, noticed that bacilli were associated with the tissues taken from patients suffering from ulcers. Look up the history of this case and describe Warren’s first hypothesis. What sorts of evidence did it take to create a credible theory based on it?