Tyndall’s Experiment

After Pasteur, John Tyndall, an English Physicist and a passionate follower of Pasteur established an important fact that was overlooked by Pasteur. He discovered the presence of “spores” of different microbes in air & in certain organic infusions. Since the spores are more resistant to heat, the organic infusions are often not sterilized after heat treatment giving rise to controversy in favor of spontaneous generation theory. He established that even after prolonged heating of 5½ hr the spores are not killed. So he mentioned that all bacteria have two phases, one thermo-labile phase (destroyed after 5mins of heating) and one thermo-stable phase. His views were supported by a German Botanist Ferdinand Cohn, who also like Tyndall worked with hey bacteria. Since hey is not a very good source of nutrient the bacteria are starved & as a result endospores are produced (spores are dormant phase of bacteria, fungi, lower plants & protozoa to survive the harsh environmental condition. They may also be called reproductive cells as favorable condition gives to the following organisms).