The world of microbes came to life in the last quarter of the 19th century under the inquisitive eyes of European and American investigators. A science of bacteriology emerged, making it possible to diagnose centuries-old diseases. To bacteriology and its sister parasitology, virology, immunology and mycology joined the ranks of disciplines eventually known as microbiology. At the University of Pennsylvania, home of the nation's first medical school (opened in 1765), the science of microbiology immediately melded with practical clinical applications. First within the confines of a modest hospital laboratory and a pathology department, next in the Laboratory of Hygiene and finally in the William Pepper Laboratory of Clinical Medicine, clinical microbiology came into its own. And in the tradition of this medical institution, Penn clinical microbiologists pioneered research, supported first-rate patient care and educated generations to carry on their work, a mission that continues today.

scientist at the microscope