When President T. C. Abbot could not expand the size of the College during the 1860s, he focused on the quality of education. Abbot worked hard to perpetuate Williams' vision of a "whole man" educational approach. He took the College back to its original mixed liberal/practical curriculum taught by learned scholars. By the 1880s these included botany professor William J. Beal, an early experimental botanist, pre-geneticist, who invented a hardier strain of hybrid corn through cross-fertilization. Beal corresponded with Charles Darwin and championed the laboratory, or "inductive", teaching method. He conducted his classes in the first botanical laboratory building on an American campus. Another distinguished faculty member was the alumnus-turned-professor, Liberty Hyde Bailey. Often called the "Father of American Horticulture", Bailey was the first person to raise the study of horticulture to a science equal to botany. Other noteworthy 19th Century faculty included Walter B. Barrows, who was a nationally-respected ornithologist whose treatise "Michigan Bird Life" is widely considered the most comprehensive study of the subject, while Rolla C. Carpenter (B.S. 1873) was a building construction specialist as well as a pioneering HVAC engineer.