In the 19th Centrury, everal experiments on human digestion were conducted on someone with a gunshot wound that left a fistula providing access to the stomach,

In the 19th Centrury, everal experiments on human digestion were conducted on someone with a gunshot wound that left a fistula providing access to the stomach, somewhat like those cannula: https://en.wikipedia.org/wiki/William_Beaumont#Experiments_with_St._Martin https://en.wikipedia.org/wiki/William_Beaumont#Experiments_w...