The germ theory was established in the mid-1800s. The germ theory posited that certain germs were the cause for numerous diseases. This idea was first put together by a French chemist, Louis Pasteur (1822-1895), when he wrote about it in a newspaper which was published in 1861. The germ theory became a “fact” after Pasteur’s and Robert Koch’s(1843-1910, a German physicist) research were put together, they proved that a germ is a living organism that can cause diseases. In addition Koch was also able to isolate certain types of bacteria as the root cause for particular diseases such as anthrax, tuberculosis, cholera and also a cattle disease known as rinderpest. The first germ that was linked to a particular disease was the anthrax germ. Thanks to Pasteur and Koch’s work, by the end of the 1800s researches had discovered the kinds of bacteria and germs that were responsible for diseases such as the: bubonic plague, diphtheria, dysentery, gonorrhea, leprosy, malaria, pneumonia, tetanus and many other infectious diseases.