Another interesting sidelight that occurred at this time... I mentioned earlier, a man's name Maurice Hilleman who was a co-discoverer of this large group of viruses called the adenoviruses. He made this discovery when he was at Walter Reed Hospital in Washington DC while I was at Charlie Pomerat's lab in Texas. By the time I returned to Philadelphia, to the Wistar Institute, Maurice became vice president of vaccine development at Merck and he became known worldwide as probably the world's best vaccine maker and he was indeed the producer of many major human virus vaccines. He was a wonderful guy, complicated personality. I enjoyed his company very much despite the fact that his... one of his main characteristics that some people were not... didn't approve of is that he punctuated most of his sentences with four-letter words. Very much like your Mr Ramsay in the UK who is... is using the same kind of language to correct errors in failing restaurants.

So Maurice had this characteristic which I found not disturbing and sort of funny. It was so bad I remember that in his office at Merck, his secretary sat outside the wall that separated his actual office from her chair and typewriter and a hole was put in the wall between... that separated the two of them, so that... so that a little door could be closed when he chatted with visitors using his foul language, so that this secretary would not hear him. I mention this because one day, soon after the publication of this paper and prior to that, Maurice and the people that worked for him... there were two people that worked for Maurice who were graduate students with me at the University of Pennsylvania, so of course I knew a lot about what was going on there and they had cooperated with me in sending me virus samples to be tested on the cell strains that I discovered, so there was a rather close relationship. We were also... those two men were... we were close socially as well. So one day I got, and as I indicated, the diploid cells were sent to Maurice early on at his request so that they could use them in research on vaccine development in order to overcome this serious problem that I'll return to later, in which primary monkey kidney cells had a large number of unknown viruses that... that posed a risk to vaccine development if they would remain in a vaccine.

One day I got a call from Maurice, which was quite unusual and I can remember his words which I won't repeat entirely here for reasons that I just explained. He said, 'Len, is there anyone else at that institute who's doing any work but you?' I said, 'What do you mean?' 'Well', he said, 'you've come up this year with the diploid cell strains and now you're in an entirely different field and you've discovered the aetiology of walking pneumonia.' I said, 'Well, I have no excuse for what I did.' And he said, 'Well, I want a culture of those mycoplasmas that you're working with, after some other colourful sentences.' I said, 'Sure, send somebody down and they're yours.' That stands out because Maurice was, of course, a very senior person and to have him recognise my work – I'm still a very young fellow – was impressive.

And Maurice himself was a very impressive person. Indeed, a book, a biography was written about him a couple of years ago that's worth reading. He was born and raised in Montana in the Midwest in the United States and it's hard to believe that he grew up to be as great a virologist as he was, coming from that kind of... sort of common origin and was capable of tangoing easily with people like Jonas Salk and Albert Sabin, etc. So this... this was impressive and I began to have other interactions with Maurice over the years after that phone call.