[Protista] Early microscopes offered sharp vision: Images from the
first microscopes were clearer than was once believed.
(by wolfbat359a from mindspring.com)
Mon Mar 7 11:15:31 EST 2011
Early microscopes offered sharp vision
Images from the first microscopes were clearer than was once believed.
The first microscopes were a lot better than they are usually given
credit for. That's the claim of microscopist Brian Ford, a specialist
in the history and development of these instruments based at the
University of Cambridge, UK.
Ford says it is often suggested that the microscopes used by
seventeenth-century pioneers such as Robert Hooke and Antony van
Leeuwenhoek gave a blurry view of biological structures such as cells
and microorganisms. Hooke was the first to record cells, seen in thin
slices of cork, while Leeuwenhoek described tiny 'animalcules',
invisible to the naked eye, in rain water in 1676.
The implication is that these breakthroughs involved more than a
little guesswork and invention. But Ford has looked again at the
capabilities of some of Leeuwenhoek's microscopes, and says the
results were "breathtaking", and comparable to those obtained with a
modern light microscope. He describes his studies in Microscopy and
Inept modern reconstructions have given seventeenth-century
instruments a bad name, says Ford. In contrast to the hazy images
shown in some museums and television documentaries, the right lighting
and focusing can produce micrographs of startling clarity using
original microscopes or modern replicas ( see slideshow ).
"Ford is the world's leading expert on the topic, and what he has to
say here makes a good deal of sense," says Catherine Wilson, a
historian of microscopy at the University of Aberdeen, UK.
Ford made some of these improvements when he was granted access to one
of Leeuwenhoek's original microscopes owned by the Utrecht University
Museum in the Netherlands. Leeuwenhoek, a linen merchant living in
Delft, made his own instruments using a single lens a tiny bead of
glass mounted in a metal frame. These simple microscopes were harder
to make and use than the more familiar two-lens compound microscope,
but offered greater resolution.
Hooke popularized microscopy in his 1665 masterpiece Micrographia,
which included stunning engravings of fleas, mites and the compound
eyes of flies. The diarist Samuel Pepys judged it "the most ingenious
book that I ever read in my life". Ford's findings show that Hooke was
not, as some have suggested, embellishing his drawings from
imagination, but should genuinely have been able to see such things as
the tiny hairs on the flea's legs.
Even Hooke was temporarily foxed, however, when he was tasked with
reproducing Leeuwenhoek's results. It took him more than a year before
he could see these animalcules, whereupon he wrote: "I was very much
surprised at this so wonderful a spectacle, having never seen any
living creature comparable to these for smallness."
"The abilities of those pioneer microscopists were so much greater
than has been recognized," says Ford. He attributes the misconception
to a recent decline in the teaching of microscopy
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