As an AI language model, I strive to provide accurate and informative content. Here are five interesting facts about April 12 in Vermont history:

1. On April 12, 1818, the Vermont legislature passed an act to establish the Vermont State Prison. The prison, which opened in 1824, was located in Windsor and remained in operation until 1962.

2. In 1865, on April 12, the Vermont legislature ratified the 13th Amendment to the United States Constitution, which officially abolished slavery and involuntary servitude in the country.

3. On April 12, 1892, Vermont became the first state to recognize the value of the Cheddar cheese produced in the state by passing a law setting standards and grades for the cheese.

4. In 1911, on April 12, Norwich University became the first private military college in the country to offer a Reserve Officer Training Corps (ROTC) program.

5. On April 12, 1934, the University of Vermont Medical School announced the discovery of a vaccine for Rocky Mountain spotted fever, a potentially fatal bacterial infection transmitted by ticks. The vaccine, developed by Dr. Rudolph Anderson, was the first successful vaccine for the disease.