Acton, indeed, was by no means without a gift of rhetoric, and in the "Lecture on Mexico," here republished, there is ample evidence of a power of handling words which should impress a popular audience. It is in gravity of judgment and in the light he can draw from small details that his power is most plainly shown. On the other hand, he had a little of the scholar's love of clinging to the bank, and, as the notes to his "Inaugural" show, he seems at times too much disposed to use the crutches of quotation to prop up positions which need no such support. It was of course the same habit--the desire not to speak before he had read everything that was relevant, whether in print or manuscript--that hindered so severely his output. His projected _History of Liberty_ was, from the first, impossible of achievement. It would have required the intellects of Napoleon and Julius Cæsar combined, and the lifetime of the patriarchs, to have executed that project as Acton appears to have planned it. A _History of Liberty_, beginning with the ancient world and carried down to our own day, to be based entirely upon original sources, treating both of the institutions which secured it, the persons who fought for it, and the ideas which expressed it, and taking note of all that scholars had written about every several portion of the subject, was and is beyond the reach of a single man. Probably towards the close of his life Acton had felt this. The _Cambridge Modern History_, which required the co-operation of so many specialists, was to him really but a fragment of this great project.
Two other causes limited Acton's output. Towards the close of the seventies he began to suspect, and eventually discovered, that he and Döllinger were not so close together as he had believed. That is to say, he found that in regard to the crimes of the past, Döllinger's position was more like that of Creighton than his own--that, while he was willing to say persecution was always wrong, he was not willing to go so far as Acton in rejecting every kind of mitigating plea and with mediæval certainty consigning the persecutors to perdition. Acton, who had as he thought, learnt all this from Döllinger, was distressed at what seemed to him the weakness and the sacerdotal prejudice of his master, felt that he was now indeed alone, and for the time surrendered, as he said, all views of literary work. This was the time when he had been gathering materials for a _History of the Council of Trent_. That this cleavage, coming when it did, had a paralysing effect on Acton's productive energy is most probable, for it made him feel that he was no longer one of a school, and was without sympathy and support in the things that lay nearest his heart.