“The discovery of anesthesia in the 1840s was immensely important—although while it made extended operations possible, overwhelming postoperative infections killed many patients, so most surgery remained a last-ditch effort. Another major advance was the spread of clean water supplies in urban areas, greatly reducing epidemics of waterborne diseases, such as typhoid and cholera, which had ravaged cities for centuries. Then finally, beginning in the 1850s and 1860s, it was discovered that many diseases were caused by specific microorganisms, as was the infection of wounds, surgical and other. The germ theory of disease, the most powerful idea in the history of medicine, was born, and medicine as a science was born with it. ”
