"Surely You're Joking, Mr. Feynman!" - unam.

my time learning the biology part.
There was one useful lab technique I learned in that course which I still use today.
They taught us how to hold a test tube and take its cap off with one hand (you use your
middle and index fingers), while leaving the other hand free to do something else (like
hold a pipette that you're sucking cyanide up into). Now, I can hold my toothbrush in one
hand, and with the other hand, hold the tube of toothpaste, twist the cap off, and put it
back on.
It had been discovered that phages could have mutations which would affect their
ability to attack bacteria, and we were supposed to study those mutations. There were
also some phages that would have a second mutation which would reconstitute their
ability to attack bacteria. Some phages which mutated back were exactly the same as they
were before. Others were not: There was a slight difference in their effect on bacteria ­­
they would act faster or slower than normal, and the bacteria would grow slower or faster
than normal. In other words, there were "back mutations," but they weren't always
perfect; sometimes the phage would recover only part of the ability it had lost.
Bob Edgar suggested that I do an experiment which would try to find out if the
back mutations occurred in the same place on the DNA spiral. With great care and a lot
of tedious work I was able to find three examples of back mutations which had occurred
very close together ­­ closer than anything they had ever seen so far ­­ and which partially
restored the phage's ability to function. It was a slow job. It was sort of accidental: You
had to wait around until you got a double mutation, which was very rare.
I kept trying to think of ways to make a phage mutate more often and how to
detect mutations more quickly, but before I could come up with a good technique the
summer was over, and I didn't feel like continuing on that problem.
However, my sabbatical year was coming up, so I decided to work in the same
biology lab but on a different subject. I worked with Matt Meselson to some extent, and
then with a nice fella from England named J. D. Smith. The problem had to do with
ribosomes, the "machinery" in the cell that makes protein from what we now call
messenger RNA. Using radioactive substances, we demonstrated that the RNA could
come out of ribosomes and could be put back in.
I did a very careful job in measuring and trying to control everything, but it took
me eight months to realize that there was one step that was sloppy. In preparing the
bacteria, to get the ribosomes out, in those days you ground it up with alumina in a
mortar. Everything else was chemical and all under control, but you could never repeat
the way you pushed the pestle around when you were grinding the bacteria. So nothing
ever came of the experiment.
Then I guess I have to tell about the time I tried with Hildegarde Lamfrom to
discover whether peas could use the same ribosomes as bacteria. The question was
whether the ribosomes of bacteria can manufacture the proteins of humans or other
organisms. She had just developed a scheme for getting the ribosomes out of peas and
giving them messenger RNA so that they would make pea proteins. We realized that a
very dramatic and important question was whether ribosomes from bacteria, when given
the peas' messenger RNA, would make pea protein or bacteria protein. It was to be a very
dramatic and fundamental experiment.
Hildegarde said, "I'll need a lot of ribosomes from bacteria."
Meselson and I had extracted enormous quantities of ribosomes from E. coli for