Barretr—On Entoptie Vision. 135 
an area where no shadows of the vessels are seen, and around this 
area the finer branching capillaries appear to me to end abruptly. 
This area is at the retinal extremity of the line of sight, and 
surrounds the point of fixation. Some of the retinal vessels I 
observe cross each other. In certain positions of the eye I have 
occasionally noticed that the shadows of the vessels where they 
spread from the optic nerve can be seen. In this case the light 
must fall obliquely on the retina in order to cast the shadows 
outside the area of the blind spot. 
One part of the area where there are no vessels presents a 
peculiar appearance, being covered with what appears to be the 
shadow of small round cells, closely grouped together. Except 
for these shadows the intensity of the light over this area seems to 
be greater than in the remaining part of the field. On moving 
my head upwards the shadows of the vessels move downwards; but 
the granular area, or shadow of the cells, moves in an opposite 
sense, but at a much slower rate. The point of light illuminating 
the sclerotic being fixed, the upward movement of the head will 
cause the point of light to descend, and the projected image of the 
vessels must therefore be formed, as shown in fig. 1, p. 127. The 
cells of the granular area are probably in the fovea ; and, owing to 
the fact that there is a depression in the retinal surface at this 
point, the ight must fall almost perpendicularly to enable the 
appearance to be seen. I have noticed that there appear to be 
two layers of these cells, for they do not all move at the same 
rate when the head or eyeball is moved ; one layer appears nearer 
the sensory filaments than the other. 
When pressure is exerted on the side of the closed eye, the 
vessels immediately appear, but they now appear as a bright 
arborescent figure on a dark field ; the impression is not, however, 
sufficiently enduring or strong enough to enable me to draw the 
figure seen. 
3. Moving corpuscles.—Pressure on the side of the closed eye 
also sometimes reveals streams of luminous spots having a pulsatory 
motion, which appears to synchronize with the beats of the pulse. 
These moving corpuscles can, however, be seen more clearly by 
looking at a bright sky through cobalt-blue glass. I have attempted 
to depict them in fig. 2, Plate VIII. There appear to be two classes 
SCIENT. PROC, R.D.S., VOL. XI., NO, XII. 8 
