Acclaimed chemist Pasteur is regarded as the father of bacteriology. It was through his elegant work in the lab that much of what became accepted viral theory was developed. Though his initial interests were pure chemistry, Pasteur eventually moved on to disease research. His demonstration of how an organism's virulence could be attenuated through various mechanisms and how vaccination with an attenuated organism could prevent disease, formed the basis of prophylaxis against a variety of diseases including diphtheria, yellow fever, and plague. Pasteur's reputation was assured through his work on rabies. The Institut Pasteur was founded in 1888 for the treatment of the disease; Pasteur was the first director.