Cathy John: My diagnosis with MS has taught me the wisdom of 'gathering ye rosebuds while ye may'

Tolstoy once quoted an Eastern parable, which he felt summed up the three responses to the utter absurdity of life in light of the certainty of death.

A traveller, he told, runs across a plain chased by an "enraged" beast. He jumps into a well to avoid being caught. But lying in wait at the bottom of a well is a dragon with his jaws open ready to eat the traveller who clings to a branch growing from the wall. The man looks up and sees that there are two mice gnawing away at the branch. He recognises that his death is inevitable, but then he notices drops of honey on a leaf that he can reach with his tongue and lick.

The traveller is faced with three options: to give in to the absurdity of life and drop into the jaws of the dragon, to struggle up the branch despite the fact that his efforts will likely be in vain, or to sit tight, lick the honey and enjoy the sweetness of life whilst he still can.

When you are diagnosed with a serious illness, you are hit hard with unequivocal evidence of your physical fallibility; you can plainly see the dragon at the bottom of the well snapping its jaws. When I was diagnosed with the (generally) degenerative and debilitating multiple sclerosis, I realised hanging on to the branch was going to get progressively more difficult and that the dragon would probably also get a couple of good goes at my ankles before my time was through. I decided I might as well lick the honey whilst I still could. The mice weren't gnawing as quickly as they might and my condition wouldn't imminently threaten my existence.

Given that I could have been caught by the beast or have dropped right into the jaws of the dragon, the honey tasted pretty sweet. As my ophthalmologist told me: "MS is not a nice disease, but it is not the worst either." As my mother said, desperately searching for the bright side: "The doctors could have found a brain tumour – you'd be dead by now."

There are of course bad days when you are fixated with the dragon and wonder whether you will just continue to slide uncontrollably towards its cavernous mouth as the mice seem to gnaw through the branch at break-neck speed.

The hardest thing about MS is its unpredictability. It is difficult to predict when or if things will slowly fall apart. The disease can take a benign route and you can live into a relatively old age with low levels of disability. Or the disease can be progressive, shorten life expectancy and result in the loss of control of most bodily functions. This leaves a lot of room for fear, even if your present condition is good.

Some days, the drop to the well's bottom looks remote and the impetus to seize the day irrepressible given that my days at full capability are likely numbered. Other days I feel beaten by a relentless stream of worsening symptoms and I am paralysed with the fear that my descent to the dragon may be more imminent than I had hoped.

Yet as my MS nurse cheerfully reminds me "you can still get hit by that car tomorrow". Aside from the fact that my currently poor vision makes being mowed down in London traffic increasingly inevitable, the sentiment is accurate. Life is unpredictable and who knows when the mice will gnaw through anyone's branch.

Hence "licking the honey" became my own Horatian motto. Diagnosis became a vital reminder to "gather ye rosebuds will ye may".