You can still have chemistry on screen without getting on with the person. But it just makes your job a lot easier if you don't have to gird your loins, if that's not quite the right phrase, every time you're going to do a scene with that person.
“The aim of the tests carried on with these syllable series was, by means of repeated audible perusal of the separate series, to so impress them that immediately afterward they could voluntarily be reproduced.”