THE DISCOVERY by Mann and Williamson1 in 1923 that diversion of the alkaline secretions of the duodenum into the lower ileum regularly caused the development of chronic, progressive peptic ulcers in dogs, stimulated an extensive experimental study of peptic ulcer disease. Exalto2 was actually the first to produce experimental ulcers by this method but his papers unfortunately failed to find a receptive audience. Both Exalto and Mann attributed the ulcers they produced to the corrosive digestant effect of the pepsin-hydrochloric acid of the gastric content coming into contact with the jejunal mucosa when not protected by the local neutralizing and buffering action of the pancreatic juice, bile, and succus entericus. Mann was led to modify this view somewhat when his associate McCann3 found that ulcers still developed after the Mann-Williamson procedure even though the duodenal secretions were shunted back into the stomach instead of into the ileum.
MANZANO C, de la ROSA C, WOODWARD ER, DRAGSTEDT LR. The Causes of the Exalto-Mann-Williamson Ulcer. Arch Surg. 1966;93(3):492-497. doi:10.1001/archsurg.1966.01330030122025