To stop the flow of music would be like the stopping of time itself, incredible and inconceivable. Only a catastrophe of some sort produces such a break in the musical discourse during a public performance. Musicians are, of course, hardened to such interruptions during rehearsal periods, but they don’t relish them. The public, at such times, look on, unbelieving. I have seen this demonstrated each summer at Tanglewood during the open rehearsals of the Boston Symphony Orchestra. […]

Musical flow is largely the result of musical rhythm, and the rhythmic factor in music is certainly a key element that has simultaneous attraction on more than one level. To some African tribes rhythm is music; they have nothing more. But what rhythm it is! Listening to it casually, one might never get beyond the earsplitting poundings, but actually a trained musician’s ear is needed to disengage its polyrhythmic intricacies. Minds that conceive such rhythms have their own sophistication; it seems inexact and even unfair to call them primitive. By comparison our own instinct for rhythmic play seems only mild in interest needing reinvigoration from time to time.

It was because the ebb of rhythmic invention was comparatively low in late-nineteenth-century European music that Stravinsky was able to apply what I once termed “a rhythmic hypodermic” to Western music. His shocker of 1913, The Rite of Spring, a veritable rhythmic monstrosity to its first hearers, has now become a standard item of the concert repertory. This indicates the progress that has been made in the comprehension and enjoyment of rhythmic complexities that nonplused our grandfathers. And the end is by no means in sight. Younger composers have taken us to the very limit of what the human hand can perform and have gone even beyond what the human ear can grasp in rhythmic differentiation. Sad to say, there is a limit, dictated by what nature has supplied us with in the way of listening equipment. But within those limits there are large areas of rhythmic life still to be explored, rhythmic forms never dreamed of by composers of the march or the mazurca.