A very clear and useful critical summary, supplemented by some original observations, of the recent work of Jaensch and his collaborators of the Marburg school on what is claimed to be a hitherto unrecognized visual phenomenon possessing characteristics which seem to be midway between those of image and sensation.

The discovery of the Marburg investigators would seem to have some importance for psycho-analytical theory for reasons that have been pointed out in the abstract of another recent paper dealing with imagery (this JOURNAL, Vol. IV, pp. 176–177). It was there shown that there appeared to be a contradiction between, on the one hand, the rôle of image and hallucination in relation to the Pleasure Principle as generally conceived in psycho-analysis and, on the other hand, the chronological and developmental relations of sensation and image as represented in general psychological