Sir,--I am very much pleased to find that Dr. Carl du Prel now avows himself almost as much a Spiritualist as any of us. I have thought that some of his recent writings indicate this; but as I have read none of his works but Mr. Massey's translation of his "Philosophy of Mysticism" I could not be sure how far his opinions had changed. That work is a storehouse of valuable facts for the Spiritualist; but all are set forth as illustrative of the theory of "double consciousness," or "the transcendental Ego." The standpoint of the whole book may be illustrated by the author's remark as to the alleged "guides" and "guardian spirits" of mediums: "The third possibility, that the guides are actual third persons, that is, other subjects, must remain excluded until they exhibit characteristics not to be explained by even the double nature of man. But as we do not know the faculties of our second Ego, nor, therefore, how much they will explain, this is a case which cannot easily occur." (Vol. I., p. 137.) Nowhere in the entire work is it alleged that there are any phenomena which the theory of the second Ego will not explain. Now, if I understand Dr. du Prel's letter aright, he does admit that there are phenomena which imply the agency of "other subjects"--that is, of what we term 'spirits.'" It is to be wished that the later works, to which Dr. du Prel refers in his letter, could be translated into English for the benefit of those Spiritualists who, like myself, are unable to read them in the original.

Alfred R. Wallace.