THE personal references with which Dr. Lang and Mr. Thomas honour me in this entertaining booklet are gratifying in so far as they show that the discussion between Dr. Lang and myself, although now of ancient date, remains occasion of mental disquiet. Dr. Lang's touching allusion to his continued hepatic troubles commands my unabated sympathy, the more so as I fear that they may retard his conversion. Mr. Thomas seems to mistake logomachy for logic. He quotes me as contending that, as the phenomena which savages attribute to spirits are explained by science as due to natural causes, spirits do not exist That is rather a travesty of what I said; but let it pass. Then he offers a parallel. Some ignorant rustics attributed the working of a steam-driven machine to horses inside it; they were mistaken; therefore, horses do not exist! Surely the ordinary man, who has never had Mr. Thomas's advantages of a course of Mill or Jevons, will reply that, in the one case, the rustics referred the mystery to known or ascertainable causes, since they had seen horses doing divers kinds of field work; while in the Other case, the mysteries are ascribed to a cause of which the savages know, and can know, nothing. The savage and the spiritualist are at one in explaining what puzzles them as due to something of which they are totally ignorant. But their conceptions of that "something" prevent the application of the saying, "Omne ignotum pro magnifico."