Physical studies of DNA had, of course, been under way for some years before analysis of virus particles began.

When I began playing around at being a physical chemist, I enjoyed very much doing work on the structure of DNA molecules, something which I would never have dreamed of doing before I started.

Because the thing about viruses is that they're easily manipulated. The DNA they inject doesn't have to be destructive. It can be replaced with almost any kind of DNA you want, and it can be programmed to only replace certain parts of the host's genetic code. In other words, viruses are perfect vectors for genetic engineering.

Of course there are depressing periods when nothing appears to be happening. But whenever anything was happening, and even when nothing was happening, it was fun just to do phage experiments.

That's the nice thing about doing research. Whatever you do is novel, so you always have this sense of novelty, even if you are only using a new gadget.

Different viral species contain nucleic acids that differ not only in length and nucleotide sequence but in many unexpected ways as well.