Robert Koch and his team of scientists identified the germs that cause diphtheria, typhoid, pneumonia, gonorrhea, meningitis, whooping cough, tetanus, plague, leprosy, syphilis, and more—that's some important work! Over a period of 100 years, scientists went from not believing germ theory to learning to control and fight them. Viewers explore the history of microbiology and this major shift in knowledge with the 24th episode from Crash Course History of Science video series.