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HISTORY OF DENTAL SUEGEKY 319

lower central incisors to the center of each condyle and the third side the dis-
tance between the center of condyles, the writer proceeded to show that the
arc of a circle, drawn with the combined diameters of a central, lateral and
cuspid tooth as a radius, the curve of the front part of an arch in any normal
case would be accur;itely represented. Then, if another line were drawn from
the point representing the distal surface of the cuspid to the condyloid angle
of the triangle, this line would pass through the crests of tlie Imccal cusps of
the bicuspids and the disto-buccal cusps of the molars.
This being the guide as to normality, it was argued that by measuring the
diameters of a central, lateral and cuspid of any plaster cast representing a
case for orthodontic treatment, a figure could be drawn upon cardboard ac-
cording to the outlined plan, which would accurately represent the arrange-
ment and form of arch that should be produced in the ])atient to represent
normality. In this way it was said any practitioner, and especially an inex-
perienced one, could supply himself with a visible and accurate guide to l)e
followed in his rearrangement of the malposed natural teeth.
In a lafer presentation of this subject, I~>r. Hawley said he had found that
the variations in width of the anterior teeth did not cover a very wide range
and that, therefore, diagrammatic card charts could be prepared in limited
luimber, each representing a certain width of anterior teeth, and that in any
j.roposed case of regulating by measuring the widths of tiic anterior teeth and
.electing the chart representing .such measurement, the practitioner would have
a guide readv for his purpose.
A later suggestion was that the guide cards l)e prepared of transparent
celluloid, which could be laid upon the plaster cast from time to time to see
that the movements being produced were in accordance with the design.
The idea of Dr. Hawley is a novel one and seemingly possessed of merit,
Ijut whether it will be generally adopted can only be determined by time.
In thus reviewing the history of Orthodontia it will be noticed that greater
advancement in both the art and science of this important specialty has been
made in the last twenty years than in the fifty years preceding. Instead of
the random attempt to move a misplaced tooth into alignment which once
seemed to be the 'solo object of the oi)erat(ir. the practitioner of to-day takes
a broader view and is concerned not so much with the movement of individual
teeth as with the restoration of alignment in both arches and establishing a
condition of nurmal occlusion which shall not only subserve the best purposes
of mastication but also restore the harmonv of the features.