And, indeed, however much private study may contribute to success, there is still a peculiar proficiency that the courts alone can give: for there the atmosphere is changed and the reality of the peril puts a different complexion on things, while, if it is impossible to combine the two, practice without theory is more useful than theory without practice.

This is from the Lapham’s series on commencement speeches… by Quintillian.

And also this, which could be right out of The Bramble Bush:

Consequently, some who have grown old in the schools lose their heads when confronted by the novelty of the law courts and wish that it were possible to reproduce all the conditions under which they delivered their exercises. But there sits the judge in silence, their opponent bellows at them, no rash utterance passes unnoticed and all assumptions must be proved, the clock cuts short the speech that has been laboriously pieced together at the cost of hours of study both by day and night, and there are certain cases which require simplicity of language and the abandonment of the perpetual bombast of the schools, a fact which these fluent fellows completely fail to realize. And so you will find some persons who regard themselves as too eloquent to speak in the courts.