The Early Days of Microscopy

Question 1

The early mention of the lens:

Aristophanes (424 BC)
Pliny (1st Century AD)
Alhazen (AD 962-1038)
Robert Grossetest and Roger Bacon (13th century AD)

Answer 1

Aristophanes - in his play “Clouds” he uses a burning lens (convex) as a plot device
Pliny - Mentioned that Physicians in Rome used burning lenses to create therapeutic burns, also mentioned that a globe filled with water magnifies small objects
Alhazen - mentions that transparent sphere can produced an enlarged image. Also describes how the lens of the eye produces an image on the retina
Gross and Bacon - Describe what appear to be telescopes, and Bacon describes eyeglasses, burning lenses, and magnifiers.

Question 2

When was the compound microscope invented and who invented it? Was there an earlier model?

Answer 2

1590 by Han Lippershey and Zacharias Janssen

Galileo is known to have built his own compound microscope in 1609

Question 3

Compound microscopes have what compared to one lens magnifiers? How is this negative for viewing?

Answer 3

two lenses and higher magnification than one-lens magnifiers BUT they have more aberrations, which impairs accute viewing

Question 4

Why were people hesitant to accept microscopes?

Answer 4

Because they thought they were misleading (distorting image) and unnatural (they are enhancing senses beyond normal extent)

Question 5

What was the first drawing of a magnified biological object? who made the observation and in what year?

Answer 5

a BEE was observed by Francisco Stelluti in 1630

Question 6

Who was Robert Hooke (1635-1703)?

Answer 6

Curator of the royal society in london

Question 7

What did Robert Hooke do?

Answer 7

set up a new microscope demonstration every week for the society’s meetings. He gathered his observations in his book “Micrographia” in which he discribed the elements of a magnified cork “CELL”

Question 8

Who completed in structural terms the model of blood circulation of W. Harvey?

Answer 8

Marcello Malpighi of Bologna who examined frog lungs, and saw the capillary connections between arteries and veins

Question 9

What else beside frog lungs did Malpighi look at under the microscope?

Answer 9

he observed the early stages of embryological development in chickens

Question 10

What is the view of an epigeneticist?

Answer 10

thought that form arose from formlessness

Question 11

What is the view of a Preformationists?

Answer 11

thought that because form was growth, form arose from pre existing form

Question 12

What did Leeuwenhoek (1632-1723) do ?

Answer 12

He was a cloth merchant and amateur scientist

Question 13

Hoe did Leeuwenhok get into microscopes?

Answer 13

he used them to examine different fabrics

Question 14

What did Leeuwenhoek microscopes look like/ how did he acquire them? What was the benefit of one lens? Was it a compound microscope?

Answer 14

he made his own single lens microscopes.

The one lens meant that they had few aberrations but still allowed him to magnify thing 100-200x, his microscopes were not compound.

Question 15

How did van Leeuwenhoek record his scientific findings?

Answer 15

he sent letters (400) to the royal society of england

Question 16

What were some of leeuwenhoek’s results? (4)

Answer 16

Blood circulation - he discovered blood capillaries independently of Malpighi after him

Microorganisms- wishing to find out why pepper tastes hot, he incubated pepper in water and then looked through his microscope ( he expected to see small needles) but saw bacteria. Independently observed protozoa.

Generative cells- a medical student drew his attention to tiny motile cells he had seen in semen of a patient with gonorrhoea

Spontaneous generation disproval - he doubted that corn in storage could spontaneously produce corn weevils, and he followed the corn weevil like cycle from egg to egg to disprove this

Question 17

What happened to microscopy after the 17th century until the 19th century? What happened in the 19th century?

Answer 17

Microscopy was not as popular, some people owned microscope but it was seen more as a toy. Leeuhawk never taught anyone or showed how he made his microscopes

The 19th century saw introduction of lenses with fewer abberations and clearer viewing