RELATIONS TO OTHER SCIENCES 413 



organ of vision, conditioned by its limitations, of value as they serve 

 it. On the other side few processes of human physiology are without 

 important bearing on ocular nutrition; and more distant processes, 

 biologic, chemic, and physical, throw light upon the problems of 

 ocular nutrition. On the one hand we have the mathematic and 

 physical phenomena of light; on the other the physiologic balance 

 of health and the imbalance of disease. 



Ophthalmology was developed from both sides. The physicist and 

 the optician with lenses and more elaborate instruments endeavored 

 to correct the imperfections and extend the usefulness of the dioptric 

 apparatus. The physician traced and combated in the eye morbid 

 processes similar to those that he dealt with in other organs of the 

 body. There is still a reactionary tendency to split the field of oph- 

 thalmology along the old lines. From the side of the optician the 

 desire for maximum immediate material results with a minimum 

 of science; and from the side of the physician the unwillingness to 

 overstep the traditional boundaries of a medical education, and train 

 the ophthalmologist in mathematic and physical optics, still favor 

 one-sided and partial studies and views of ophthalmology. The real 

 unity of science, and the importance of the sense of vision in the life 

 of our modern civilization will, in the end, compel a view of the whole 

 field from the true standpoint. But the opposing influences of a hasty 

 commercialism, and a blind if not fossilized conservatism, must be 

 met by the assertion and reassertion, clear and emphatic, of the unity 

 of ophthalmology. 



Physics and Mathematics. The two halves of the ophthalmic 

 domain have been alluded to. Let us go into the relations of each of 

 them a little more in detail before turning to special lines of thought 

 that lead out toward the other domains of science. On the physical 

 side of ophthalmology the general laws of refraction and the proper- 

 ties of lenses have been worked out nearly to the practical limit of 

 minuteness. The exact changes in the dioptric mediums and surfaces 

 of the eye, which occur with age, and in the act of accommodation, 

 are still uncertain. This point at which physics and physiology come 

 together is one of especial interest. More minute studies of both the 

 physical conditions present in the crystalline lens and the physio- 

 logic processes which change them may yield suggestions of wide 

 applicability both in general physiology and in general physics. 



That part of the physical side of ophthalmology concerned with the 

 movements of the eyeball, which secure and maintain binocular 

 vision, has of late years attracted much attention. A voluminous 

 literature regarding it has arisen, the bulk of which, to speak frankly, 

 is worth very little. This literature exhibits with painful emphasis 

 the general lack of a broad training among physicians which leaves 

 them unable to grasp and use to advantage essential physical and 



