Richmond, Ind., July 31, 1899.
To the Editor:
—In the Journal of July 29, there is a letter by Dr. Murphy of Kansas City as to "Misleading Statements and Illustrations in School Physiologies, Physics, and in Text-Books on Diseases of the Eye," but unfortunately in this case it is Dr. Murphy who is misleading. He states that the text-books teach that parallel rays of light focus on the retina in the normal eye. This is just what they have taught, do teach, and always ought to teach.The first three illustrations, which he states are incorrectly drawn, are just as correct as his Figures 5, 6 and 7. Possibly some slight objection may be made to them all, in that they take for their basis the old ray theory, which is entirely superseded by the wave theory.Scheiner's experiment any one can perform by taking a visiting card through which