This experiment which I feel creepy from History

Alexis St. Martin was a fur trader who was at the wrong place at the wrong time.

A shotgun had accidentally been shot at him.

Doctor William Beaumont was quickly called to inspect the wound. The shotgun had ripped a hand-sized hole into St. Martin’s stomach.

Beaumont attempted to repair the wound with no success. St. Martin could not eat without the food spilling through the hole in his stomach; he was forced to be fed through anal injections.

That’s when Beaumont's curious mind took over. There was a living stomach for him to experiment on.

At the time, it was debated whether the stomach digested food mechanically or chemically. Beaumont could find out.

Beaumont began spooning food into St. Martin’s stomach only to dig it out later. Beaumont would dangle meat on a string into the hole and then pull it out to observe.

Beaumont performed more than 200 experiments over the next 10 years on St. Martin. St. Martin chose to go through the experiments because he was very poor, and the money Beaumont gave him was more than he could’ve gotten.

Beaumont was able to determine that food is digested chemically. For this he is known as the "Father of Gastric Physiology".