The subject which I have taken on this occasion for my paper, is one which can be dealt with at great length or very briefly. I prefer to select the latter course without, I hope, detracting from its interest. Since Bonwill there have been a good many who have written about the formation of the dental arch, both in a horizontal and in a vertical position. With regard to the vertical direction, Dr. Wholy, as far as I know, has spoken the last word, and I will now take the liberty of giving you my experiences as to the horizontal direction. Far be it from me to appear to say anything new; but I should like to call the attention of the profession to this important portion of that large subject to which our teacher, Dr E. H. Angle, has devoted his whole life with such thoroughness. By the title ‘normal occlusion’, I do not mean a condition of the arches, where the teeth are standing in rightly formed arches and where the teeth and jaws are in proper relation to each other, but I do mean a condition where these factors being present the horizontal curve of the dental arch so far corresponds with the curve of the glenoid fossa, that by moving the lower jaw forward until the incisal edges or sideways until the buccal cusps of the molars and bicuspids meet one another — the dental arches do not become separated, but remain parallel to each other and touch one another at several points (Figures A …