In 1793, Italian anatomist Michele Vicenzo Malacarne described experiments in which he paired animals, trained one of the pair extensively for years, and then dissected both. He discovered that the cerebellums of the trained animals were substantially larger. But these findings were eventually forgotten. The idea that the brain and its function are not fixed throughout adulthood was proposed in 1890 by William James in "The Principles of Psychology", though the idea was largely neglected. Until around the 1970s, neuroscientists believed that the brain's structure and function was essentially fixed throughout adulthood.