Another danger lies in the testimony of witnesses who have a certain sense of form in representation and whose inferential leaps consists in their omitting the detailed expression and in inserting the notion of form instead. I learned of this notable psychosis from a bookkeeper of a large factory, who had to provide for the test of numberless additions. It was his notion that if we were to add two and three are five, and six are eleven, and seven are eighteen we should never finish adding, and since the avoidance of mistakes requires such adding we must so contrive that the image of two and three shall immediately call forth the image of five. Now this mental image of five is added with the actual six and gives eleven, etc. According to this we do not add, we see only a series of images, and so rapidly that we can follow with a pencil but slowly. And the images are so certain that mistake is impossible. “You know how 9 looks? Well, just as certainly we know what the image of 27 and 4 is like; the image of 31 occurs without change.” This, as it happens, is a procedure possible only to a limited type, but this type occurs not only among bookkeepers. When any one of such persons unites two events he does not consider what may result from such a union; he sees, if I may say so, only a resulting image. This image, however, is not so indubitably certain as in the case of numbers; and it may take all kinds of forms, the correctness of which is not altogether probable. E. g., the witness sees two forms in the dark and the flash of a knife and hears a cry. If he belongs to the type under discussion he does not consider that he might have been so frightened by the flashing knife as to have cried out, or that he had himself proceeded to attack with a stick and that the other fellow did the yelling, or that a stab or cut had preceded the cry--no, he saw the image of the two forms and the knife and he heard the cry and these leap together into an image, i.e., one of the forms has a cut above his brow. And these leaps occur so swiftly and with such assurance that the witness in question often believes himself to have seen what he infers and swears to it.