It is to be regretted that Plattner's aversion to the idea of post-mortem dissection may postpone, perhaps for ever, the positive proof that his entire body has had its left and right sides transposed. Upon that fact mainly the credibility of his story hangs. There is no way of taking a man and moving him about _in space_, as ordinary people understand space, that will result in our changing his sides. Whatever you do, his right is still his right, his left his left. You can do that with a perfectly thin and flat thing, of course. If you were to cut a figure out of paper, any figure with a right and left side, you could change its sides simply by lifting it up and turning it over. But with a solid it is different. Mathematical theorists tell us that the only way in which the right and left sides of a solid body can be changed is by taking that body clean out of space as we know it,--taking it out of ordinary existence, that is, and turning it somewhere outside space. This is a little abstruse, no doubt, but anyone with any knowledge of mathematical theory will assure the reader of its truth. To put the thing in technical language, the curious inversion of Plattner's right and left sides is proof that he has moved out of our space into what is called the Fourth Dimension, and that he has returned again to our world. Unless we choose to consider ourselves the victims of an elaborate and motiveless fabrication, we are almost bound to believe that this has occurred. So much for the tangible facts. We come now to the account of the phenomena that attended his temporary disappearance from the world. It appears that in the Sussexville Proprietary School, Plattner not only discharged the duties of Modern Languages Master, but also taught chemistry, commercial geography, book-keeping, shorthand, drawing, and any other additional subject to which the changing fancies of the boys' parents might direct attention. He knew little or nothing of these various subjects, but in secondary as distinguished from Board or elementary schools, knowledge in the teacher is, very properly, by no means so necessary as high moral character and gentlemanly tone. In chemistry he was particularly deficient, knowing, he says, nothing beyond the Three Gases (whatever the three gases may be). As, however, his pupils began by knowing nothing, and derived all their information from him, this caused him (or anyone) but little inconvenience for several terms. Then a little boy named Whibble joined the school, who had been educated (it seems) by some mischievous relative into an inquiring habit of mind. This little boy followed Plattner's lessons with marked and sustained interest, and in order to exhibit his zeal on the subject, brought, at various times, substances for Plattner to analyse. Plattner, flattered by this evidence of his power of awakening interest, and trusting to the boy's ignorance, analysed these, and even made general statements as to their composition.