rnment servants. The first experiment station in the modern era
began in Connecticut in 1875, and in 1887 the Congress established such
stations in every state in conjunction with the agricultural Land Grant
colleges. Scientists at many of the stations also made discoveries in
animal nutrition. For example, as a result of animal feeding experiments
E. V. McCollum discovered vitamins A and B at the experiment station in
Wisconsin in 1915.

None of these scientific advances left much residue in the form of
artifacts for museums, but the reality of the changes should not be
obscured by the lack of objects on exhibit. Even so, some of the related
equipment survived. For example, the centrifuge used in the butterfat
test, discovered in 1890 by Stephen M. Babcock, survived in several
forms. Manure spreaders and tree sprayers, reflective of advances in
biochemistry, also survived. But these only suggest the more important
biological control activities for which these machines and tools served
merely as agents in some way.

The 20th century introduced Americans to total war. World Wars I and II
demanded the total mobilization of all resources by all contenders. In
both conflicts America became the food reservoir of the Allies. From a
technological view, the wars engendered a level of prosperity which both
allowed and encouraged farmers to adopt new methods and devices. The
principal technological change in farms was the widespread adoption of
the internal combustion tractor, first used in 1892. Inventors and
manufacturers gradually but constantly improved tractors along with the
various devices attached to them. Most notable were the corn picker, in
1909, and the cotton picker, in 1942. (Dates are for commercial
production in each instance.) Farmers found both machines impracticable
until a power source independent of the ground wheel had been developed.
More than anything else the tractor and its related equipment finally
set men free from the worst drudgery of farming. It also set many
farmers free from the need to farm at all.

The tractor and its equipment accomplished several other remarkable
things, some obvious and some not so obvious. First, it allowed the
farmer to get rid of horses and mules, and these animals steadily
declined--to such an extent that in the 1960s the census did not even
bother to count them. As a result of this decline, land that farmers had
used to raise feed for animals could grow food for people