Musar על עבודה זרה 37:10

Thus it was in the land of France that they occupied themselves with great industry and much time, and they would sit in one place to study all of the Talmud, and they would constantly review, and the Torah did not cease from their mouths. And they did according to the deeds of the earlier Sages, as they said, "Let one by all means learn, even though he is liable to forget, yea, even if he does not fully understand all of the words which he studies" (Abodah Zarah 19a). And they said, "That a man should study and subsequently understand." And all of this they do not do now, for everyone wants to study Tosafot, and new interpretations before he knows even the structure of the Talmud. This being the case, how can they make any progress? For they do the opposite of what the Sages of the Talmud said, for everything that is said in the Talmud is all true and one ought not to take issue with it or change it, nor add to it nor subtract from it.