I am sorry to say that my expertise is only relevant if the root of the hair is present. With the follicles, one could find chromosomes to analyse family relations, minerals to reveal where the person lived if they had stayed in the same geographic area for long enough.

I suggest you talk to some television shows and perhaps the mother will come forward. I think she is hoping for just that, since at the moment she doesn’t know that the bottle has been found. It would doubtless comfort her to share her grief. And if she talks about it, perhaps it would help her grieving process.

‘Talk to some television shows’ sounded deceptively simple. It seemed to me that the locks of hair must offer some clues, perhaps from a more mainstream analyst than this follicologist cum bereavement counsellor.

On every French high street, and especially in the wealthy part of Paris where I stayed and where the population tended to be elderly, there are laboratories offering medical analysis, where people can bring in a blood or urine sample and have it checked. I asked whether they could do a DNA sample on a lock of hair. The receptionist, fiddling with her silvery watch strap, confirmed what the follicologist had said, that it was impossible. One cannot do DNA samples on hair because there are no cells. When I questioned this, uncertain of my hazy scientific knowledge, she assured me, patting her own elaborate, cell-free coiffure into place, that she was a highly qualified biologist and knew she was right.

It seemed to me that with a lock of hair – even without follicles – and surely some skin or saliva cells somewhere in the bottle, some trace DNA would be present. I realized that I was basing this conclusion on late nights watching American forensic police thrillers.

In an attempt to discover whether an analysis of the DNA in a lock of hair would bring me any closer to discovering the identity of Maurice or his mother, I started to read up on the process. DNA stands for deoxyribonucleic acid. In 1984 Alec Jeffreys, a geneticist at Leicester University, announced his findings on DNA fingerprinting, a term he soon patented. As early as December 1985, another scientific breakthrough – PCR, polymerase chain reaction – meant that minute quantities of DNA could be copied and amplified, so that scientists could provide themselves with enough material with which to carry out forensic investigations. These breakthroughs meant that even a tiny trace of the stuff could help to identify or eliminate suspects by determining each individual’s unique genetic code.