Italy 1546 About contagion and Contagious Diseases - Girolamo Fracastoro - Diseases were due to a contagion that could be transferred from one person to another by direct contact with the person or by touching objects contaminated by the afflicted person (fomites). Contagions were destructive particles whose heat, moisture or other characteristics caused destructive changes. Many contagions attack only specific animals or humans, or specific crops or trees, or specific organs of the body.
Holland 1650's Anton von Leeuwenhoek ground single lens microscopes and made the first observations of microorganisms in rain water, peppercorn infusions and teeth scrapings. It is possible that he first made and used the microscopes in his cloth importing and exporting business. In 1673 he sent the first in a series of letters to the Royal Society of London (England) about his findings.England 1665 Robert Hooke used a compound microscope to observe thin slices of cork, among other things and coined the name "cells" to describe the pores he found in the cork. He was also important for many innovations in the development of microscopy.
Italy 1668 Francesco Redi demonstrated that maggots (fly larvae) do not arise spontaneously from decaying meat as was commonly believed. Three sealed jars and three open jars, all containing meat. All the meat decayed, but only the open jars produced maggots. The counter argument to this was that air was necessary for generation. A second experiment in which the open jars were covered with a fine net showed production of maggots on the net, but none on the meat, even though air was present.
This was a blow to spontaneous generation, but many believed that the small "animalcules" observed by van Leeuwenhoek were simple enough to arise by spontaneous generation, and others believed that the experimental protocols disturbed the generative forces.England 1745 John Needham showed that even boiled chicken broth or corn infusions sealed into covered flasks would become contaminated by microorganisms, giving strength to this latter view.
Europe 1700's variolation discovered from previous eastern writings and used to combat smallpox. It worked, but was dangerous.
Italy 1776 Lazzaro Spallanzani showed that Needham's results were due to microorganisms from the air, as broth boiled in a sealed flask remained free of contamination. Needham said that the "vital force" had been destroyed by heat and kept out of the flask by the seals.
England 1798 Edward Jenner used material from cowpox to vaccinate humans against smallpox.
France 1807Benedict Prevost found a fungus that caused a disease in wheat, and was the first to propose that disease was caused by living organisms.
Italy 1835 Agostino Bassi found a fungus that caused a disease in commercial silkworms.
Germany 1838 - 1839 Matthias Scheiden and Theodor Schwann proposed that all living creatures were composed of cells - the Cell Theory of life.
Germany 1839 J. Schoenlein and David Gruby found that a fungus caused chronic ringworm (such as athlete's foot - Tineia pedis).
Germany 1839 B. Lagenbeck found that a yeast caused thrush, a human mouth infection.
Germany 1840's - 1850 Ignaz Semmelweis, noted that in maternity wards where doctors didn't wash their hands after doing autopsies, there were many deaths in childbirth. When they were required to wash their hands with an antiseptic solution, the death rate decreased from 8.3% to 2.3%. He proposed that the doctors were carrying the disease on their hands and instruments: the Germ Theory of disease. For this he was dismissed from his post at the hospital, eventually went insane and died.
England 1845 J.M. Berkley characterized the fungus that causes potato blight (endemic in Ireland at the time).
France 1853Anton De Bary Described the fungi that cause plant smuts and rusts. Also described the life cycle of the fungus that causes potato blight.
Germany 1858 Rudolph Virchow proposed the concept of biogenesis: living cells can only arise from preexisting living cells.
England 1859 Charles Darwin presents a paper on the Origin of Species.
France 1860 Louis Pasteur, famous for founding polarimetry, was called in to discover the cause of the souring of beer and wine in France's beverage industries. Pasteur found that yeasts caused the fermentation of sugar to alcohol in the absence of air and other bacteria later caused a change to vinegar (sour acetic acid) in the presence of air. He invented a process of heating (pasteurization) to kill the bacteria after the yeast fermentation was complete.France 1861 Louis Pasteur used his swan necked flask experiment to "kill" spontaneous generation - some of his flasks are still sterile. However this experiment isn't any better than Redi's or Spallanzani's in concept, and some of his flasks, in which he used a hay infusion actually became contaminated (due to bacterial spores about which nothing was known at the time), and it was a combination of his great prestige, the experiments, the wealth of accumulated data and the changing outlook of the times that killed the old theory. However, life on earth did begin as a form of spontaneous generation, although it is not observed now (why not?).
England 1860's Joseph Lister Used solution of carbolic acid (weak solutions of phenol) to treat wound dressings and decrease infection.
Austria 1864 Gregor Mendel published a paper on inheritance.
Germany 1876 Robert Koch proved (for the first time) that bacteria cause disease. A commercially important cattle disease, anthrax, was destroying many cattle. Koch found rod shaped bacteria (bacilli) in the dead tissues. He isolated them, grew them in media, reintroduced them in healthy cattle, saw them develop the disease and die, and then he reisolated the same bacterium from the newly dead cattle. He established Koch's postulates, which are still used today: