select for desirable traits (such as large ear size) when breeding. Hayes and East later found described that a cross, or hybrid, between two inbred varieties of corn produced offspring that was more vigorous, larger and hardier that both of the parents, but this improvement was lost over successive inbred generations. In 1914, Donald F. Jones arrived at the station at the age of twenty-five, and began to build upon the work of East and Hayes. By 1917, he had published his theory of “heterosis,” which explained the increased vigor and yield observed in hybrid maize. The same year, he created a double-cross hybrid corn by breeding two separate hybrid individuals. This new cross descended from four distinct inbred lines, and was even more vigorous than either of its parents. However, like the single-cross hybrid, this improvement was lost over subsequent generations of inbreeding. Jones published his double-cross method in 1919, and began actively promoting the technique as a means to improve corn production nationally: “it is something that may easily be taken up by seedsmen; in fact, it is the first time in agricultural history that a seedsman is enabled to gain full benefit from a desirable origination of his own… The utilization of first generation hybrids enables to originator to keep the parental types and give out only the crossed seeds, which are less valuable for continued propagation.” Because corn is a self-fertilizing plant, the prevention of inbreeding when producing hybrid seeds required time-consuming detasseling. In the 1940s and 50's, Jones collaborated with Paul Mangelsdorf of Harvard University to eliminate the need to remove the tassels from plants in seed production through utilizing a sterile plant and male restorer gene, making the production of corn more cost-efficient. "Morgan" method of soil testing Dr. M. F. Morgan, Chief of Soils Department for twenty years, developed a method that still bears his name to test for soil nutrients that are available to plants using weak acids. This test was able to estimate deficiencies or excesses of plant nutrients in soil. Dr. Morgan was also a Lieutenant Colonel in the U.S. Army during World War II, and was killed in action on the Leyte Island in the Philippines in 1945. Morgan's soil test became the world's first widely accepted method for efficiently estimating soil fertility, and is still in use today. Tick-borne diseases In 1975, there was a cluster of juvenile