LONG BEFORE THE ERA OF RAILROAD EXPANSION ENDED, carriers had established development and improvement programs to boost productivity in the areas they served. In this, St. Louis Southwestern (SSW or Cotton Belt), which ran through eastern and southern Arkansas on its way from St. Louis to Texas, was typical. Cotton Belt instituted its own agricultural and industrial department, owned and operated demonstration farms and demonstration forests, issued its own promotional literature, and outfitted exhibition cars as educational vehicles.1 If none of this was unusual for a major railroad in the first three decades of the twentieth century, there was one area-malaria control-in which Cotton Belt's contributions were distinctive. They followed on the heels of a pioneering project carried out by the Rockefeller Foundation and Arkansas public health officials in 1916 that substantially reduced malaria in the community of Crossett, in southeastern Arkansas. Employing similar techniques, Cotton Belt's private campaign would become another significant element in the fight against malaria in Arkansas and East Texas.2 Medical and governmental authorities had been taken aback by the Spanish-American War, in which thirteen times as many U.S. troops in Cuba died from yellow fever, malaria, or typhoid fever as from military action. Walter Reed and, then, William Crawford Gorgas, both Army physicians, along with medical doctors elsewhere, began studying tropical diseases and gradually linked some of them to the as carrier. In the case of malaria, it became clear that the female spotted wing mosquito-specifically, the female Anopheles-was the villain, in earlier times, common wisdom had held that the contraction of malaria derived from drinking impure water or from sleeping in night air. But scientists eventually concluded that malaria was a disease of the blood and that victims carried parasites of malaria in their blood after being bitten or stung by mosquitoes. In fact, the female spotted wing was harmless as hatched, acquiring her infection only after sucking blood with the malaria parasites from a carrier or victim of malarian In short, the human host provided the reservoir from which the replenished her supply of parasites each successive season. But the mosquito theory proved a tough sell. Policy makers and the general public remained skeptical in the extreme. After the United States took up the cause of completing an isthmian canal across Panama and deaths to dreaded diseases mounted, Gorgas and others made real progress in turning President Theodore Roosevelt's attention to matters of sanitary and hygienic conditions in the construction area. Others, too, gradually came around to accept or at least tolerate the theory.3 To control malaria meant to break communication between the and infected persons on the one hand and unsuspecting persons on the other. Most immediately, one could screen windows and-by draining and ditching-eliminate pools of standing water in which mosquitoes bred.4 The need for such efforts within the United States was abundantly clear. H. R. Carter, assistant surgeon general of the United States, asserted in 1921 that where malaria seriously prevails it does more injury to the community than any other disease. Five years earlier, Senator Joseph E. Ransdell, a Louisiana Democrat, had complained that, for the year 1913, the loss to the country from malaria was over $694 million-affecting most directly persons in southeastern and southern states but also northern investors who held securities in southern industries.5 Railroads and several classes of railroad employees-at least in those southeastern and southern portions of the country-were among those at considerable risk. The disease sapped energies of railroaders and made them less efficient, but also hit farmers and employees of industries along their routes to the detriment of production and thus to maximum traffic flows. …