Rarely does a classical music society share a venue with a jazz quartet.

Evidently, that's no fluke.

Last weekend, the Handel & Haydn Society, a Boston-based period orchestra, hosted the Modern Jazz Quartet at Symphony Hall. The groups offered three performances of Bach Variations, a concert designed to harmoniously integrate Bach and blues.

Christopher Hogwood, the artistic director of the baroque society, explained that Bach Variations was "part of [the Society's] exotic programming" and effort to incorporate various branches of music into one mellifluous concert.

And since Hogwood considered the Modern Jazz Quartet (sort of the granddaddy of performing jazz groups) to be the "most appropriate" guest by the Society's stuffy standards, he thought it natural to invite them to Boston for a little jam session.

From the start, there was no doubt that the concert would be a challenging project.

But Bach Variations deserved the benefit of the doubt; the proof would lie in the performance.

Unfortunately, the program proved unspectacular.

The Society, with Linda Quan on violin and Hogwood conducting from his harpsichord, opened the program harmlessly enough with Bach's Sinfonia in F, BWV 1046a.

Hogwood then introduced the Modern Jazz Quartet--actually a trio, since Connie Kay, the group's drummer, was under medical observation. Their first piece, Blues in B, was composed by pianist John Lewis. This light arrangement, which emphasized Milt Jackson's vibraharp, seemed to waft through the air.

The highlight of the program was their second selection, Don't Stop this Train. Using Bach as a framework, Lewis created a set that bounced along, prodded by his fancy fingerwork on the piano.

The finale of the two-hour concert was the Society's rendition of Bach's Brandenburg Concerto No. 4, BWV 1049, which led straight into the Quartet's own arrangement of Elemental Bach, a bluesy piece that jump-started the audience from their slumber.

Although Bach Variations had its redeeming qualities, the concert's overall impression was unremarkable.

Part of the problem lay in the intrinsic stodginess of the Handel & Haydn Society.

On the right side of the stage, you have a group of musicians that have become the premiere period orchestra, apostles of "Historically Informed Performance." On the left are three musicians who are masters of a thriving contemporary musical form. The two groups seem fundamentally incompatible.

And indeed they are. Hogwood's plan to fuse baroque and jazz failed primarily because of that sticky area where classical music doesn't seem to operate: improvisation.

As fans know, the defining characteristic of good jazz music is the style and skill of the artist in improvisation. Placed onstage next to a flock of tuxedoed musicians sawing away on 17th and 18th century violins, the Quartet seemed to forget this. The quartet/trio simply didn't improvise.

The absence of the Quartet's drummer made things that much worse. Traditional blues and jazz require drums. Period. Having to listen to the antiseptic sounds of a vibraharp, bass, and piano just doesn't cut it.

For any jazz fan, the Society would have been unbearably boring were it not for the aural relief provided by the Modern Jazz Quartet. Or, considering the concert's stuffy slant, was it be the other way around? The difference was barely perceptible.