I WAS a bit taken aback in the middle of December, just before we were all consumed by Yuletide, when a correspondent remarked that he hadn't enjoyed violinist Jonathan Morton's arrangement of Grieg's String Quartet, written up for string orchestra in the form of Morton's Scottish Ensemble.

What was not to like, I wondered? My acquaintance felt that in "bigging up" the piece, especially with the doubling of the strings and the inclusion of the double bass, the quartet lost that intimacy which is the essence of chamber music.

That's the funny thing about taste: I had felt quite the opposite. I commented in my review of the performance that (however exactly I expressed it) there is, within the intimacy of Grieg's Quartet, an intrinsic bigness in its scale, structure and aspiration that is almost symphonic, as though the music, while perfectly satisfactory in its original format, is straining for a bigger canvas on which to stretch its limb. In arranging it up for a bigger group, Jonathan Morton actually demonstrated his psychological insight into the innards of the music, as well as an acute appreciation of the macrocosmic dimensions of the piece.

The fact is that some music lovers just do not like the composer's original and decisive version of a piece being tampered with in any way, shape or form. How such people cope with the infinite decoration and ornamentation that goes on at every level of the texture in Baroque performance, where (an extreme, I admit) you could have a singer on the top line lavishing all manner of vocal embellishments onto the melodic line, while the harpsichord or organ, underpinned by a cello and operating from what's called a figured bass, could be filling out the texture and harmony with all manner of richness of invention, I just don't know.

And that's actually today's topic: transcriptions and arrangements per se will be a major issue in the coming months, and I'll pick that one up later. I think things are freer now, with greater tolerance of individuality and expressive flexibility, than they were 40 years ago, but you will always come up against purists (or extremists) in every form of music.

I had a tiny experience of that myself when I played piano (not very much and not very well) during my university years in Aberdeen at the end of the 1960s. At one point I was learning George Gershwin's Preludes for Piano (there are three of them). Two points are relevant here: I have always loved Gershwin's music; second (don't laugh) through my playing days I was first a bit of a rocker, pounding out Jerry Lee Lewis style (though my right leg was never quite long enough to hoist it up onto the piano without me falling flat on my bahookey) and later a wee bit of a jazz and blues pianist (both very useful in my teaching days in Clydebank).

Back in Aberdeen and Gershwin's Preludes; the second is a blues number. It's archetypal with the distinctive Gershwin flavour, but the music cries out for a few touches here and there of that idiomatic blues technique where you elide between two or more notes, one of them being a flattened note. It's the pianistic equivalent of "bending" a note on a guitar or woodwind instrument, such as Gershwin himself incorporated into the top of the fantastic clarinet opening runway into the Rhapsody In Blue.

Anyway, I decorated a few of Gershwin's notes with an appropriate slide or two. My tutor froze. Silence fell. "You can't do that," he muttered, in what I took to be horror. "Play only what's written." I explained in an ardent student manner (youthful arrogance?) that this was appropriate to the style and idiom, and anyway folk were doing it in Baroque music now (which made matters worse) and I felt sure that Gershwin would recognise it and not disapprove (matters were now infinitely worse).

"Play only what is written."

So I did, then went off to the pub to muse on issues of intolerance and inflexibility.