paleontological, and these were typically about very large-scale phenomena. Though
he observed small fossils to the level of foraminifera (see discussion of this below),
fossils below this scale were unknown in his time. Other non-microbiological areas
of his studies, many pursued to support his larger theories, included coral reef
formation, animal breeding, barnacles, orchids, honeybees, the effects of seawater
on seeds, climbing plants, ants, expression of emotions, the evolution of man,
insectivorous plants, flowers, the movement of plants (phototaxis and
circumnutation), animal intelligence and instinct, and earthworms.
His interest in microbes was largely expressed through his correspondence about
Pasteur’s work and Koch’s discoveries (see below). He was interested in the cause of
the potato blight and supported work by Miles J. Berkeley in the USA and provided
financial assistance to potato breeder James Torbitt who sought to introduce diseaseresistant plants in England and Ireland (Ristaino and Pfister 2016). He even cultivated some potato varieties that he had sent back from Peru on the Beagle voyage in
an effort to find disease-resistant varieties (Ristaino and Pfister 2016). There is no
evidence that he ever cultured microbes, though he did observe a tube of sterile
medium sent to him by Tyndall who asked him to open it and report whether
microbes grew in it (Darwin Correspondence Project Letter no. 10207 2020c).
They did of course, thus providing Tyndall with support for his contention that
microbes were in the air everywhere and so providing evidence to discount the
theory of spontaneous generation.
2.3 Darwin and Microbes
Darwin was a very good microscopist. He wrote a chapter entitled “On the Use of the
Microscope on Board Ship” in the 1849 book A Manual of Scientific Enquiry;
Prepared for the Use of Her Majesty’s Navy: and Adapted for Travelers in General
(Darwin 1849). Darwin in his later studies used a compound microscope that could
achieve a magnification of 1300 X, though he apparently used it at lower power since
it was prone to visual aberrations, as were all microscopes at that time (Jardine
2009). He could certainly see bacteria with this kind of microscope, but he did not
comment on them in any of his writings.
Darwin lived until April 1882, so he overlapped with scientists known to have
made contributions to bacteriology including Louis Pasteur, Ferdinand Cohn, Robert
Koch, Martinus Beijerinck, and Sergei Vinogradskii (Fig. 2.2). Of these, there are
only copies of correspondence with Cohn, though the contributions of Pasteur and
Koch are mentioned in other letters.
During Darwin’s lifetime, 1809–1882, the concept of microorganisms changed
radically. Since their description in detail by Antonie van Leeuwenhoek in 1683, the
nature of bacteria was little studied until the early nineteenth century. This may have
been due to the fact that few could reproduce the lenses that van Leeuwenhoek
constructed. Studies of the larger protozoa and yeast cells made progress, however,
and the role of yeast cells in fermentations became the subject of heated debate in the
2 Darwin’s Science’s Impact on the Evolution of the Microbiological Sciences
21
he observed small fossils to the level of foraminifera (see discussion of this below),
fossils below this scale were unknown in his time. Other non-microbiological areas
of his studies, many pursued to support his larger theories, included coral reef
formation, animal breeding, barnacles, orchids, honeybees, the effects of seawater
on seeds, climbing plants, ants, expression of emotions, the evolution of man,
insectivorous plants, flowers, the movement of plants (phototaxis and
circumnutation), animal intelligence and instinct, and earthworms.
His interest in microbes was largely expressed through his correspondence about
Pasteur’s work and Koch’s discoveries (see below). He was interested in the cause of
the potato blight and supported work by Miles J. Berkeley in the USA and provided
financial assistance to potato breeder James Torbitt who sought to introduce diseaseresistant plants in England and Ireland (Ristaino and Pfister 2016). He even cultivated some potato varieties that he had sent back from Peru on the Beagle voyage in
an effort to find disease-resistant varieties (Ristaino and Pfister 2016). There is no
evidence that he ever cultured microbes, though he did observe a tube of sterile
medium sent to him by Tyndall who asked him to open it and report whether
microbes grew in it (Darwin Correspondence Project Letter no. 10207 2020c).
They did of course, thus providing Tyndall with support for his contention that
microbes were in the air everywhere and so providing evidence to discount the
theory of spontaneous generation.
2.3 Darwin and Microbes
Darwin was a very good microscopist. He wrote a chapter entitled “On the Use of the
Microscope on Board Ship” in the 1849 book A Manual of Scientific Enquiry;
Prepared for the Use of Her Majesty’s Navy: and Adapted for Travelers in General
(Darwin 1849). Darwin in his later studies used a compound microscope that could
achieve a magnification of 1300 X, though he apparently used it at lower power since
it was prone to visual aberrations, as were all microscopes at that time (Jardine
2009). He could certainly see bacteria with this kind of microscope, but he did not
comment on them in any of his writings.
Darwin lived until April 1882, so he overlapped with scientists known to have
made contributions to bacteriology including Louis Pasteur, Ferdinand Cohn, Robert
Koch, Martinus Beijerinck, and Sergei Vinogradskii (Fig. 2.2). Of these, there are
only copies of correspondence with Cohn, though the contributions of Pasteur and
Koch are mentioned in other letters.
During Darwin’s lifetime, 1809–1882, the concept of microorganisms changed
radically. Since their description in detail by Antonie van Leeuwenhoek in 1683, the
nature of bacteria was little studied until the early nineteenth century. This may have
been due to the fact that few could reproduce the lenses that van Leeuwenhoek
constructed. Studies of the larger protozoa and yeast cells made progress, however,
and the role of yeast cells in fermentations became the subject of heated debate in the
2 Darwin’s Science’s Impact on the Evolution of the Microbiological Sciences
21