. Elementary physiology . Fig. 125.—View of the posterior part of the retina. A.—The posterior half of the retina of the left ej-e, viewed from before. (Henle.) Twice the natural size. s, cut edge of the sclerotic ; ch, choroid ; r, retina : in the interior at the middle the macula luteawith the depression of the fovea centralis is represented by a slight oval shade ; towards the left side the light spot indicates the colliculus or eminence at the entrance of the optic nerve, from the centre of which the arteria centralis is seen sending its branches into the retina, leaving the pait occupied
. Elementary physiology . Fig. 125.—View of the posterior part of the retina. A.—The posterior half of the retina of the left ej-e, viewed from before. (Henle.) Twice the natural size. s, cut edge of the sclerotic ; ch, choroid ; r, retina : in the interior at the middle the macula luteawith the depression of the fovea centralis is represented by a slight oval shade ; towards the left side the light spot indicates the colliculus or eminence at the entrance of the optic nerve, from the centre of which the arteria centralis is seen sending its branches into the retina, leaving the pait occupied by the macula com- paratively free. has in its central part a slight depression called the fovea centralis. The fovea centralis lies at the opposite pole of the eyeball from the pupil, and is the part of the retina upon which vision is most acute. When the attention is directed to an object, the eyeballs are so turned that the image of it is focussed upon the fovea centralis and the parts of the macula lutea adjoining. Objects, of which the images are cast upon other parts of the retina, are only seen very indistinctly, and are more indistinct as their images fall more distant from the fovea centralis. The existence of the blind spot may be easily demon- strated by making two round dots on a piece of white paper, each about one-tenth of an inch in diameter, and about two
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Keywords: ., bookcentury1800, bookdecade1890, bookpubli, booksubjectphysiology
