Louis Pasteur - You can see his name on your milk.
He made this discovery.
Spontaneous generation
Classical notions of abiogenesis, now more precisely known as
spontaneous generation, held that complex, living
organisms are generated by decaying organic substances; according to
Aristotle it was a readily observable truth that
aphids arise from the dew which falls on plants,
fleas from putrid matter, mice from dirty hay, crocodiles from rotting logs at the bottom of bodies of water, and so forth.
In the 17th century such assumptions started to be questioned; such as that by
Sir Thomas Browne in his
Pseudodoxia Epidemica, subtitled
Enquiries into Very many Received Tenets, and Commonly Presumed Truths, of 1646, an attack on false beliefs and "vulgar errors." His conclusions were not widely accepted, e.g. his contemporary,
Alexander Ross wrote: "To question this (i.e., spontaneous generation) is to question reason, sense and experience. If he doubts of this let him go to
Egypt, and there he will find the fields swarming with mice, begot of the mud of
Nylus, to the great calamity of the inhabitants."
[8]
In 1546 the physician
Girolamo Fracastoro theorized that epidemic diseases were caused by tiny, invisible particles or "spores", which might not be living creatures, but this was not widely accepted. Next,
Robert Hooke published the first drawings of a microorganism in 1665. He is also credited for naming the cell which he discovered while observing cork samples.
Then in 1676
Anthony van Leeuwenhoek discovered microorganisms that, based on his drawings and descriptions are thought to have been
protozoa and
bacteria. This sparked a renewal in interest in the microscopic world.
[9]
The first step was taken by the
Italian Francesco Redi, who, in 1668, proved that no
maggots appeared in meat when flies were prevented from laying eggs. From the 17th century onwards it was gradually shown that, at least in the case of all the higher and readily visible organisms, the previous sentiment regarding spontaneous generation was false. The alternative seemed to be
omne vivum ex ovo:
that every living thing came from a pre-existing living thing (literally, every living thing from an egg).
In 1768
Lazzaro Spallanzani proved that
microbes came from the air, and could be killed by boiling. Yet it was not until 1861 that
Louis Pasteur performed a series of
careful experiments which proved that organisms such as bacteria and fungi do not appear in nutrient rich media of their own accord in non-living material, and which supported
cell theory.
But then Darwin Comes in to Cover his Ass.
Darwin and Pasteur
By the middle of the 19th century
Pasteur and other scientists discovered the theory of
Biogenesis by demonstrating that
living organisms do not arise spontaneously from non-living matter.
In a letter to Joseph Dalton Hooker on February 1, 1871,[10]Charles Darwin made the suggestion that the original spark of life may have begun in a "warm little pond, with all sorts of ammonia and phosphoric salts, lights, heat, electricity, etc. present, so that a protein compound was chemically formed ready to undergo still more complex changes".
He went on to explain that "at the present day such matter would be instantly devoured or absorbed, which would not have been the case before living creatures were formed."
[11] (What - is this not faith)