112 
ME. J. W. HULKE ON THE ANATOMY OE THE 
Inner Granular Layer (fig. 1, 5 ). — At the centre of the fovea this layer is very thin, 
and its innermost granules are not clearly separated from the outermost cells of the 
ganglionic layer (fig. 6 ) ; but at the margin of the fovea it has already a considerable 
thickness, and the granular layer, now a distinct hand, separates it from the ganglionic 
layer. The granules are roundly oval nuclei of -000465" diameter, and larger cells of 
•000697" diameter, in some of which a nucleus is discernible. The layer also contains 
obliquely and vertically radial fibres. The latter are connected on the one side with the 
membrana limitans interna, and on the other with the thin granular band lying between 
the cone-fibre plexus and the inner granule-layer ; they are manifestly a modified con- 
nective tissue, and form conspicuous objects when examined with an objective. 
The oblique fibres are much more delicate, and require the highest magnifying powers 
for their demonstration (fig. 5). With ^ 5 " object-glass I traced their identity with the 
fibres which enter the layer from the cone-fibre plexus (fig. 4), and I have also seen the 
smaller inner granules or nuclei intercalated in the oblique fibres, and observed these 
connect themselves with the larger granules or cells. 
The Granular Layer (fig. 1, e). — This does not exist as a distinct layer at the centre of 
the fovea, but appears at a short distance from it in the angle between the inner granule 
and ganglionic layers. At the margin of the fovea it has a thickness of -001627", which 
it keeps with little variation throughout the macula. It transmits the connective tissue 
and nerve-fibres which pass between the inner granules and the ganglion-cells. 
The Ganglionic Layer (fig. 1, 7). — At the centre of the fovea the ganglion-cells do not 
lie in a continuous band, but are scattered in a double or treble series through a finely 
areolated matrix of connective tissue. At the margin of the fovea they lie closer toge- 
ther, four or five deep, in the spaces between the vertically radial connective-tissue fibres. 
Throughout the fovea and macula the cells are separated from the membrana limi- 
tans interna by a narrow granular band. This latter is structurally identical with the 
granular layer ; throughout the macula and fovea it contains optic nerve-fibres. 
Connective-Tissue Structures. — The origin and distribution of the vertically radial 
was natural : one, in which he says “ the fibres in the intergranule-layer had an oblique and horizontal curve 
(as Bergman saw them); ” another, in which “ they had a generally vertical direction broken by a double almost 
rectangular band ” h 
It does not, however, appear in their writings that Bergman, Muller, or Kolliker actually demonstrated the 
connexion of the oblique fibres of the intergranule-layer of the human macula with the elementary tissues of 
the other layers. Kolliker says that he saw processes from the cones (which he calls Muller’s fibres) in the 
intergranule-layer throughout the macula, even in the fovea itself, adding “ they can be easily followed to the 
inner granule-layer yet as he subsequently disputes Schultze’s 2 statement — that the oblique fibrillation in 
the human macula occurs in the inner part of the outer granule-layer (a layer which lies between the bacillary 
and the intergranule-layer) — he leaves the subject, even so far as his own observation goes, very ambiguous. 
1 Kolliker, Handb. der Gewebelehre, iv. Aufl. S. 674. 
s Schultze, Sitzungber. der niederrhein. Gres, in Bonn, 1861. I regret that this paper has not been within 
my reach. The reference I take from Kolliker’s ‘ Handbuch.’ 
