This blind-spot is not particularly of interest here, but it may be of interest to note its effect.
It may well occur, then, that in a movement the image happens to fall on the blind-spot and not on the fovea.
This is impossible, since the entire image and its halo as well may lie within the blind-spot.
It may be said that the image of h happens to fall on the blind-spot, e and e being above and below the same.
A three-foot circle at a distance of 36 feet will completely disappear if its image falls directly upon the blind-spot.