When I was first in Paris, in 1926-1927, I attended a concert by the Capet Quartet, whose devotion to correctness led them to play without vibrato. To play without vibrato is an excellent check upon one’s intonation and useful therefore in testing an ensemble’s accuracy, but so intolerable did my ears find it in performance that I left the hall (I have regretted my slight ever since: the Capet Quartet were superb musicians from whom I could have learned much).