Medicine Becomes a Science, 1840-1999

Scientists did not know what made people sick more than 150 years ago. There were many theories of how and why illness spread, but none of them were accurate. Though very primitive microscopes had permitted the examination of bacteria as early as the 1660s, it was not until the mid-19th century that bacteria's contribution to the spread of illness was understood. It was during this time that surgeons routinely examined patients in the morning and then performed surgeries in the afternoon - witho