After about a year at Merck, during which time I should say I met my wife, I had contact with a good friend, as I say, still at Penn [University of Pennsylvania] and pursuing a Master's Degree in the medical microbiology department, which was in the Medical School, unlike the College of Liberal Arts and Sciences where the microbiology training that I had took place. And he kept me apprised as we met from time to time, of what he was working on. He happened to be working on what was then called pleuropneumonia-like organisms. Today the name is 'mycoplasma'. These organisms are the smallest free living organisms, that is, they're so small yet they have the ability to grow on a dead source of nutrients. That distinguishes them from viruses, which are a bit smaller than these mycoplasmas, but can only replicate on a living cell or in a living cell.

And as time grew... passed I became more and more interested, not only in these organisms, but also in the idea of going back to Penn and trying to get a higher degree. I realised by this time that that might be doable. I went in to see my... to see Wasserman and Verwey, they encouraged me, which was a big plus. Of course I was living at home still with my parents and so my financial obligations were very low and my income at that time was... was great for a single fellow living at home and paying very little for his upkeep, and so I had accumulated modest savings. And I think I accumulated sufficient savings to go to Penn for one year. So that did indeed happen. I made application for Graduate School and in particular, to be accepted by a professor in that department who was the leading authority on these microorganisms.