mass vaccination programs in colonies in 1803. By 1832, the federal government of the United States established a smallpox vaccination program for Native Americans. Under the direction of Mountstuart Elphinstone a program was launched to increase smallpox vaccination in India. From the beginning of the 20th century onwards, the elimination or control of disease in tropical countries became a necessity for all colonial powers. The sleeping sickness epidemic in Africa was arrested due to mobile teams systematically screening millions of people at risk. The biggest population increases in human history occurred during the 20th century due to the decreasing mortality rate in many countries due to medical advances. Colonial policies contributing to indigenous deaths from disease John S. Milloy published evidence indicating that Canadian authorities had intentionally concealed information on the spread of disease in his book A National Crime: The Canadian Government and the Residential School System, 1879 to 1986 (1999). According to Milloy, the Government of Canada was aware of the origins of many diseases but maintained a secretive policy. Medical professionals had knowledge of this policy, and further, knew it was causing a higher death rate among indigenous people, yet the policy continued. Evidence suggests, government policy was not to treat natives infected with tuberculosis or smallpox, and native children infected with smallpox and tuberculosis were deliberately sent back to their homes and into native villages by residential school administrators. Within the residential schools, there was no segregation of sick students from healthy students, and students infected with deadly illnesses were frequently admitted to the schools, where infections spread among the healthy students and resulted in deaths; death rates were at least 24% and as high as 69%. Tuberculosis was the leading cause of death in Europe and North America in the 19th century, accounting for about 40% of working-class deaths in cities, and by 1918 one in six deaths in France were still caused by tuberculosis. European governments, and medical professionals in Canada, were well aware that tuberculosis and smallpox were highly contagious, and that deaths could be prevented by taking measures to quarantine patients and inhibit the spread of the disease. They failed to do this, however, and imposed laws that in fact ensured that these deadly diseases spread quickly among the indigenous population. Despite the high death rate among students from contagious disease, in 1920 the Canadian government made attendance at residential schools mandatory