Morning Tonic: Fistulated Season’s Greetings

A fistulated cow is a cow with an intentional hole in it for scientific research. In 1822, a Canadian suffered a wound that refused to heal, but the man otherwise was in fine health. His doctor discovered that the digestive process could be observed directly through the hole. The discovery spread, and for over 150 years, fistulation has been used to observe digestive processes in living animals, with the first recorded scientific use on animals dating to 1833.

– Davis Wiki