Any attempt at a scientific exp attempt at a scientific explanation of the phenomenon of “crystal seering,” to use an irregular but comprehensive term, would perhaps fall short of completeness, and certainly would de­pend largely upon the exercise of what Professor Huxley was wont to call “the scientific imagination.” The reasons for this are obvi­ous. We know comparatively little about atomic structure in relati­on to nervous organism. We are informed to a certain degree upon atomic ratios; we know that all bodies are regarded by the physicist as a congeries of atoms, and that these atoms are “centres of force.”