van Niel’s Course in General
Microbiology
His course offered an early survey of the microbial world as well as a
coherent approach for integrating biology
Susan Spath
t’s the greatest course in the
Technical University in Delft, the Netherlands.
world,” said Germain (CohenThere, van Niel adopted the broadly ecological apBazire) Stanier. She was referring
proach to microbiology developed by M. W. Beijerto C. B. van Niel’s course in geninck, the first professor of microbiology at Delft. In
eral microbiology, given most
the 1920s, A. J. Kluyver, the successor to Beijerinck,
summers from 1930 –1962 at the Hopkins Maundertook a broad, comparative survey of microbial
rine Station (HMS), Stanford University’s mametabolism from which he derived, with H. J. L.
rine laboratory on Monterey Bay in California.
Donker, the principle of the unity of biochemistry.
For some students, taking van Niel’s course was
This principle greatly impressed van Niel, and
a life-changing experience. For most it was unthroughout his life he sought to cultivate an apforgettable. From the 1930s to the
proach to microbiology now known
1950s, van Niel’s course played a
as the Delft School, which integrated
major role in developing general
both Kluyver’s and Beijerinck’s perFrom the 1930s
microbiology into a dynamic and
pectives.
to the 1950s,
respected discipline. Graduates of
In the 1920s, general microbiolvan Niel’s
van Niel’s course include Nobel
ogy was a small and fragmented
course played a
Prize winners Arthur Kornberg,
enterprise, especially in the United
Konrad Bloch, and Paul Berg as well
States. Most scientists who were
major role in
as leading scientists working in nustudying microorganisms were endeveloping
merous fields and on central probgaged in medical, industrial, and
general
lems in biology, including microbial
agricultural branches of bacteriolmicrobiology
ecology, photosynthesis research,
ogy. Only a few laboratories had
into a dynamic
plant physiology, bacterial physiolanything like sustained programs
and respected
ogy, and molecular biology.
in general microbiology. In other
words, bacteriology was almost
discipline
van Niel Saw Microbiology as
completely isolated from the main
a Means for Unifying,
branches of the life sciences. At
Systematizing Biology
HMS, van Niel was ideally situated to pursue
microbiology as a general science of life. His
When van Niel arrived at HMS in 1928, he was
vision of microbiology embraced biochemistry,
31 years old, Monterey was a quiet fishing vilphysiology, morphology, ecology, and evolulage, and Stanford was just beginning to build a
tion. Further, van Niel proposed that a unified,
research program in experimental biology. A
coherent science of general microbiology could
new laboratory, named for Jacques Loeb, had
provide a foundation for unifying the life scijust been built at HMS, and van Niel joined a
ences. They were badly fragmented, he believed,
team of researchers who were working on a
either along organismal lines or because investibroad range of biological problems.
gators followed disparate methodological apvan Niel brought to Stanford the approach to
proaches. van Niel held that integrating micromicrobiology he developed during his training at the
“I
Susan Spath is an
independent
scholar in Berkeley,
Calif.
Volume 70, Number 8, 2004 / ASM News Y 359
obtainable only by including bacterial photosynthesis, implied that the biochemical aspects
of photosynthesis could be understood in
terms of oxidation reduction reactions, an important new insight at the time.
van Niel’s Course in General
Microbiology Encouraged Broad
Thinking
View of the Hopkins Marine Station on Monterey Bay in California.
biology with other branches of biology would
necessarily create a more comprehensive and more
coherent science of life. van Niel’s belief in microbiology as a unifying force also rested on his conviction that the simpler forms of life present many
of the fundamental features of life most clearly.
Moreover, the diversity of the microbial world, he
argued, meant that investigators could almost always find ideal experimental material for studying
fundamental biochemical processes.
Today, some of these ideas may seem selfevident, but in 1929 they were not. Because so
many of these ideas are now well accepted, it
may be difficult to appreciate how unusual they
were at the beginning of van Niel’s career. In the
late 1920s, the nature of bacteria was very much
debated. Organismal biologists, especially,
tended to view bacteria as genetically and cytologically bizarre, rather than as valid living
things truly representative of more complex organisms. Moreover, it was not generally accepted that research on bacteria could yield insights of general biological importance.
Within his first year at HMS, however, van Niel
completed a major study on bacterial photosynthesis that illustrated beautifully how research on
bacteria could yield unifying concepts with implications for plant physiology, evolution, and ecology. On the basis of that research, he formulated a
general equation that applied equally to plant and
bacterial photosynthetic processes. He showed
that bacteria, like plants, use light energy to reduce
carbon dioxide to sugars. His equation, which was
360 Y ASM News / Volume 70, Number 8, 2004
van Niel’s course was probably the first in
the United States to offer a comprehensive
survey of the microbial world. From the
beginning, it was designed to convince students that microbiology offers marvelous
opportunities for research in biology. Fundamentally, its purpose was to give students
tools they needed to carry out their own
research by teaching them methods and concepts, rather than a fixed body of knowledge.
On one level, students learned many useful
methods for handling microorganisms. On another level, van Niel endeavored to teach students how to develop their powers of scientific
reasoning, emphasizing history and thereby familiarizing students with key observations on
which the current body of knowledge rested,
rather than asking them simply to accept such
knowledge. As Robert McElroy, class of 1941,
wrote, “No participant would ever forget this
course because in addition to scientific knowledge, it imparted a philosophy and a method of
thinking about the approach to biological research.” Overall, van Niel presented research in
microbiology as a part of an even greater intellectual project to obtain a unified picture of nature.
Students in the course met formally three days
a week for 10 weeks. Lectures and laboratory
work were artfully integrated. The first lecture
began at 8 A.M. and could last as long as four
hours. After lunch, van Niel often gave another
lecture, again sometimes lasting four or five
hours. However, some afternoons were instead
occupied with laboratory exercises that could
extend until midnight.
By all accounts, van Niel brought a spellbinding intensity and passion to his teaching, and his
former students remember that his lectures
could be mesmerizing, even when they lasted for
several hours. A master of the Socratic method,
van Niel would relentlessly pose questions to
and draw answers from his students.
Typically, van Niel began with a discussion of
van Niel’s Finishing School
The heyday of van Niel’s course in the 1950s and
1960s coincided with the development of molecular
biology. Because this was a microbial science, it
seemed like a good idea to many— especially those
entering from other fields such as physics—to learn
something about microbes. A paradox ensued: most
of the work in the fledgling science of molecular
biology was being done with Escherichia coli and its
phages, but these were topics that van Niel barely
mentioned. So, why was his course so popular that
eminent molecular biologists as well as their apprentices flocked to Pacific Grove as inexorably as the
swallows coming (far down the coast) to Capistrano?
Mind you, the course was meant principally for Stanford undergraduates, with the heavyweights being
allowed as auditors only.
Two answers suggest themselves. One is that the
master was not just a teacher but also a magician. All
who took the course reported that they had come
under his spell. To wit, who else could keep an audience at the edge of their seats and with pencils poised
for 8 hours or more of lecture in one day? Who else,
on other days, would lead the class in a discussion
that, hours later, ended with the conclusion that a
certain experiment would solve the problem, only to
find that the equipment for just THAT experiment
was ready at the back of the room? All this was being
the nature of science and scientific reasoning. For
example, on the first day, van Niel would ask the
class an apparently simple question, “What is microbiology?” He would use the answers to lead
into a discussion of abstract reasoning and the
importance and limitations of definitions. van Niel
emphasized that the goal of scientific research was
not only to discover facts, but to integrate them
into general principles. He also insisted that any
scientific conclusions should always be considered
as tentative because new facts might require investigators to formulate whole new concepts. The
scientific picture thus is not static but always open
to change.
When teaching the substance of microbiology,
van Niel systematically interrelated practical
methods and theoretical principles. For instance,
he connected use of the microscope to discussions
of discovering microorganisms and the debate
over spontaneous generation. When he taught the
methods for preparing pure cultures, he intro-
witnessed by a wise old sea anemone that had been
living in a tank in the laboratory for over 20 years. I
can attest to the fact that the van Niel spell can last a
lifetime.
The second reason derives from the meaning of the
Delft School of microbiology to which van Niel had
made stellar contributions. The early days of microbiology included not only its better-known medical
discoveries, but also exceptional work on the role of
microbes on the cycles of matter in nature by Beijerinck, Kluyver, and their students. They came to the
realization that, in Kluyver’s words, “Civilization
owes much to the microbe.” He could have added:
“and so does all of life.” Although the Delft school
followed a different development than molecular microbiology, it was held in high esteem. It carried so
much authority that taking a course taught by one of
its eminent members was considered a sure way to
learn about microbes in general. There may well have
been some unintended consequences. I wonder how
many people who came to Pacific Grove to take a
course that might give them a license to work with E.
coli came away with the big picture of the rest of the
microbial world instead. Not a bad bargain.
Moselio Schaechter
San Diego State University
San Diego, Calif.
duced discussions of Koch’s postulates and the
meaning of causality in science. He would also
arrange for the students to use enrichment cultures
to demonstrate how environmental conditions
contribute to natural selection.
The concluding first section of the course then
surveyed the classical topics of microbiology, such as
morphology, classification schemes, and the ecology
of yeasts and several major groups of bacteria.
During the second half of the course, van Niel
took up the subject of microbial biochemistry.
He lectured in detail on the fermentations of
various microorganisms such as yeasts, lactic
acid- and propionic acid-producing bacteria,
and anaerobic sporeformers. Typically, he saved
his favorite subjects such as photosynthesis for
last. By the end of the course, students had
gained considerable experience in handling a
wide range of microorganisms, a great deal of
substantive content, and a set of concepts with
which they could approach a wide variety of
Volume 70, Number 8, 2004 / ASM News Y 361
FIGURE 1
Kluyver and van Niel.
biological problems. van Niel established the
basic structure of the course in the 1930s and
modified it very little. Of course, as the years
passed, van Niel incorporated new findings into
this structure. Between 1947 and 1962, he wrote
out new sets of lectures every year. His notes for
1956, for example, contain 186 meticulously
detailed, handwritten pages.
Students Continue To Praise
van Niel’s Course
In the spring of 1930, when van Niel first taught
his general microbiology course, only one student
enrolled, Robert Hungate. At Stanford, Hungate
had studied a mixture of general biology, ecology,
and botany. He decided to take van Niel’s course
on the recommendation of a friend. “I was enthralled,” Hungate wrote years later about the
experience. van Niel’s “lucid presentation of ideas,
his keen memory and insight, coupled with an
intense interest in microbiology and in the student,
made an indelible impression.” Whereas Hungate
had no prior inclination toward the subject, he
decided to investigate the protozoa and bacteria in
the termite gut and their role in the digestion of
wood. The first of many won over to microbiology
by van Niel’s teaching, Hungate went on to a
distinguished career in microbiology.
362 Y ASM News / Volume 70, Number 8, 2004
Later, during the summer, Horace A.
Barker took the course and he, too,
found that van Niel “had a very impressive way of speaking. . .” and that “his
hypnotic intensity. . .made a deep impression.” Especially impressed by van
Niel’s discussions of the biochemistry
of bacterial and yeast fermentations,
Barker decided to pursue a Ph.D. in
chemistry to prepare for future research
on these subjects. He spent 1935 as a
postdoctoral fellow with Kluyver in
Delft, where he began his important research on methane-producing bacteria.
In 1936, after listening to van Niel’s lectures for a second time, Barker joined the
faculty of the University of California,
Berkeley, where he brought the Delft
School approach to a new audience.
Throughout the 1930s, a succession of
students fell under van Niel’s spell before
embarking on careers in microbiology, including Lewis Thayer, Michael Doudoroff,
Howard Bliss, Roger Stanier, Steven Carson, E. H. Anderson, and J. O. Thomas.
“My fate was decided in a few days,” Stanier wrote about his experience in van Niel’s classroom. “It took less than a week to conclude that van
Niel was the ideal master and teacher; general microbiology was to be my domain...” In 1947, Stanier
joined Barker and Doudoroff on the faculty of
Berkeley. Stanier became a leading proponent of
general microbiology in his own right. The widely
used textbook, The Microbial World, was orginally coauthored by Stanier, Doudoroff, and Edward Adelberg, and was intended to capture as
much as possible van Niel’s approach to microbiology.
As the high quality of the course became
known, researchers from a range of backgrounds traveled to HMS to take it. Photosynthesis researchers Robert Emerson, C. S. French,
and William Arnold all took the course in the
1930s, as did biochemist Hermann Kalckar.
Physicist Max Delbrück was a student in 1940
and later became a proponent of carrying out
biological research on bacteriophage. Other
graduates of the era include Robert McElroy,
Garrett Hardin, and Dixie Lee Ray. McElroy,
who first learned about bacterial luminescence
in van Niel’s course, became one of the world’s
experts on the topic. Hardin took van Niel’s
teaching in a different direction and pioneered
the field of human ecology. Ray eventually became head of the Atomic Energy Commission
and then governor of the state of Washington.
The 1940s and 1950s witnessed an explosion of
interest in research on microorganisms, especially in
genetics, making van Niel’s course an ever-morehighly valued resource. van Niel received hundreds
of applicants for each session, from which he was
limited to choosing only a dozen students along
with a dozen auditors. In the first decade after
World War II, Wolf Vishniac, Barbara Wright,
Helge Larsen, Barbara Bachmann, and F. G. Lara
received doctoral degrees under van Niel. All five
became distinguished microbiologists who continued research in van Niel’s mode.
The course played a significant role in training
physical scientists who moved into biology after
the war. For instance, Leo Szilard, Aaron Novick, Roderick Clayton, and Seymour Benzer all
were participants. While Delbrück’s phage
course at Cold Spring Harbor has been justly
celebrated for training physicists to study biology, it is important to note that many of its
participants, including Delbrück, also took van
Niel’s course. Researchers with medical backgrounds also found special value in van Niel’s
comprehensive presentation of the microbial
world, including Bernard Davis, Harry Eagle,
Ole Maaløe, Arthur Kornberg, Paul Berg, and
Seymour Lederberg. Other graduates of the
course who became leading molecular biologists
include Dale Kaiser, Bruce Ames, William Sistrom, and Elie Wollmann.
Even experienced microbiologists came to the
course. For instance, Ralph Wolfe, who is professor emeritus in the department of microbiology, University of Illinois, Urbana-Champaign,
audited the course in 1954. “The class was a
fantastic experience that opened my eyes to a
microbial world of unfamiliar organisms,” he
wrote later in recalling his experiences. “I returned to Illinois with many ideas from van Niel
that, together with some from Gunny, Luria,
Sherman, and myself, became an organisms
course that would be taught for nearly three
decades.”
van Niel’s Lasting Legacy
Following the post-World War II expansion of microbiology, van Niel’s research, teaching, and vision
continued to be major influential factors. On one
level, van Niel’s course was the direct means by
which several hundred students learned the basic
methods and substantive content of general microbiology. His students and colleagues, their students
and their colleagues, and so on, became an integral
part of the worldwide community of microbiologists. On another level, van Niel’s course became a
model for many other microbiology courses that
adopted its message and methods, in whole or in
part. Thus, van Niel and his followers greatly
stimulated thousands of others to continue exploring the microbial world.
In his teaching, van Niel advocated change, flexibility, and open-mindedness in scientific research. He
warned his students against accepting uncritically the
findings of other microbiologists, even the most famous. Surely, current innovative approaches in microbial ecology and evolution would delight van Niel
if he were alive to learn about them. In some sense,
the present era represents a fulfillment of much that
he wished for. Recent successful efforts to integrate
the microbial world into general biological understanding are now bringing forth some of the
profound consequences that van Niel envisioned as early as the 1930s.
The success of van Niel’s philosophical agenda is
less certain. To van Niel, the deepest importance of
science was its capacity to cultivate tolerance, objectivity, and rationality in the individual. He hoped
that teaching students how to think, how to evaluate
evidence, and how to distinguish between observations and inferences would lead to a better society
overall. His philosophy of science and his research
were consistent with his philosophy of life. To some
extent, that coherence was made possible by the
particular circumstances of van Niel’s scientific life.
Not everyone, however, takes advantage of such
opportunities as fully as van Niel did. For microbiologists who now operate in a world becoming morally, politically, and socially more complex, perhaps
van Niel may still serve as a model to emulate.
SUGGESTED READING
Kluyver A. J., and C. B. van Niel. 1957. The microbe’s contribution to biology. Harvard University Press, Cambridge, Mass.
Pfennig, N. 1987. van Niel remembered. ASM News 53:75–77.
Bennet, J., and H. Phaff. 1993. Early biotechnology: the Delft connection. ASM News 59:401– 404.
Spath, S. B. 1999. “C. B. van Niel and the Culture of Microbiology, 1920–1965.” Dissertation, University of California, Berkeley.
Volume 70, Number 8, 2004 / ASM News Y 363