Diseases of the Lens Opacities or Cataract =Symptoms.=—Beginning opacities can best be recognized with the ophthalmoscope. Advance opacities can be seen at a glance with the naked eye. Vision is disturbed according to degree and location of the opacity. If the opacity is in the center of the lens and the periphery is transparent they see better when the pupil is dilated. When the opacities are in the periphery of the lens they see better by day. Muscæ volitantes and polyopia are present until increasing opacity closes up all clear areas shutting out these visual perversions. There are many clinical varieties of cataracts which may be studied in works on ophthalmology. =Causes.=—Some interference with the nutrition of the lens accounts for the condition. Heredity is supposed to play a part in some cataracts. Rickets, convulsions, traumatism, old age, some drugs (ergot), inflammation of iris, ciliary body and choroid are given as causes. Cervical and upper dorsal lesions and disease of the throat, nasopharynx and nose will interfere with perfect circulation and drainage of the orbit, and may well have much to do with many idiopathic cataracts. =Treatment.=—Many cases have been reported cured by osteopathic measures. Correct lesions and treat to establish free nerve force and circulation of blood and lymph to the orbit. Manipulation of the orbital tissues and mild vibration of the bulb are measures of value. More hope may be held in symptomatic, toxic, secondary and progressive cataracts. The process may be stopped and in many cases there is hope of a clearing. Diseases of the Retina The retina lines the back part of the eye ball. It comes forward to the ora serrata. It consists of ten layers which have been demonstrated microscopically. One layer of it passes over the ciliary body and back part of the iris to the pupil. The fibers of the optic nerve spread out over the retina. The point of entrance of the optic nerve is the papilla. It is to the inner side of the posterior pole of the eye. The retinal vessels emanate there. The macula lutea is the yellow sensitive spot at the posterior pole of the eye. The fovea is the center of the macula. The rods and cones constitute the external layer of the retina. This layer is the light perceiving stratum. For vision to be perfect all the other layers must be perfectly transparent. The visual purple is a chemical substance in the rods that gives the retina a purplish-red color. The light shining into the eye forms images which are converted into nervous stimuli by chemical action of the visual purple and by physical changes and fibrillations in the rods and cones. Retinitis