Germ theory of disease
The Germ theory of disease, developed in the 1860s and 1870s by Louis Pasteur, states that tiny "living beings" are the cause of infectious diseases. Pasteur's proof of this theory involved the first scientific experiment to falsify a hypothesis, ushering an era of scientific medicine. He showed that the theory of spontaneous generation was false, by placing one piece of meat under a glass jar and another in an open dish. He observed flies landing on the exposed meat, but of course flies could not penetrate the glass jar. Flies did not come out of nothing, but from eggs deposited by flies which he could easily see landing on the exposed meat. was extremely controversial when first proposed, but today it is the backbone of modern medicine.
Prior to germ theory, it was widely believed that disease was spread by smell.[Citation Needed] As disease-spreading conditions - rotting meat, open sewage, and such things - was often highly odorous, the smell and disease were associated. Disease was also often attributed to demonic influence - although demonic posession must exist as it it mentioned in Scripture[1], it is a rare occurance, and almost all disease attributed to it was a result of other causes.
The Christian Scientist sect, founded by Mary Baker Eddy, believes that the Germ Theory of Disease is not true and that it is contradicted by Scripture.[2] God created all life, and so all life should reflect His glory and inherent goodness - God could not have created pathogenic organisms, as these are inherently contary to His nature.