Microorganisms Lenses Sense of scale Commentary

Robert Hooke, Antonie van Leeuwenhock biology

Microorganisms

• Robert Hooke described a fly’s eye,
• discovered that plants have cells,
• and drew the hairs on the back of a flea.
• Antonie van Leeuwenhock described bacteria,
• blood cells flowing through capillaries, spermatozoa,
• and insects including the parasites of the flea.
• Leeuwenhock was the first to report
• the existence of single-celled organisms.
• This strained the credibility
• of members of the Royal Society of London so
• they sent a delegation to Delft
• to see whether Leeuwenhock was a madman or a genius.
• It turned out that on good testimony
• Leeuwenhock was sane, and that Hooke was able
• to verify Leeuwenhock’s observations.

Lenses

• Leeuwenhock made his own tiny spherical lenses
• capable of magnification between 275 to 500 times
• by melting the tip of a thin thread of glass
• so that it formed a sphere. He set this sphere
• in a simple tool that held the sample to the light
• and let him adjust its position in three dimensions.
• Robert Hooke’s first microscopes
• descended from the compound lens telescope,
• but eventually he learned how to make
• tiny perfect lenses the way Leeuwenhock did.

Sense of scale

• The bulk of living things on Earth
• are smaller than our eyes, unaided, can see, and so
• it takes naïvité or a form of intellect to accept,
• in the scale of things,
• our true insignificance.