Pasteur's various investigations convinced him of the rightness of the germ theory of disease, which holds that germs attack the body from outside. Many felt that such tiny organisms as germs could not possibly kill larger ones such as humans. Pasteur now extended this theory to explain the causes of many diseases - including anthrax, cholera, TB and smallpox - and their prevention by vaccination. He is best known for his work on the development of vaccines for rabies. In 1888, a special institute was founded in Paris for the treatment of diseases. It became known as the Institut Pasteur. Pasteur was its director until his death on 28 September 1895. He was a national hero and was given a state funeral