88 W. J. DAK IN. 



cell, rod, and axial fibre, which are based on niethylene-bbje 

 methods. It appears somewhat difficult for lue to understand 

 how tlie material presumably stained could remain in good 

 condition for four years until taken up for completion. 



We are told that a rod consists of a nerve-cell whose small 

 anterior end (upper end ?) projects slightly beyond the median 

 limiting membrane, and whose much elongated posterior 

 portion is tubular and bluntly terminated. This portion is 

 encased in a hyaline sheath, Avith the end capped by a homo- 

 geneous cuticular substance, which in methylene-blue pre- 

 parations appears like the matrix separating the rods. A 

 small nucleus lies in the antei-ior end of the rods and .from 

 this an axial fibre extends to the posterior (lower end). 



There is another series of iuiportant elements in the retina 

 — " bipolar cells.^' These extend from the median limiting 

 membrane (presumably the same as the line dividing rod- 

 cells fi'om rods) outwards towards the margin of the i-etina. 

 " Their large granular elliptical nuclei may be seen in longi- 

 tudinal sections extending in a row, a short distance from 

 the median liuiitin"- membrane. The whole cell with its 

 afferent and efferent axon is encased in a hyaline sheath, 

 under which are scattered blue granules of various sizes." 

 The rest of Hyde's conclusions are difficult to understand, 

 but putting figures and descriptions together, one gathers 

 that the rod-cells of all previous writers are the same as 

 certain "supporting cells of the median layer" of Hyde. 

 The bipolar nerve-cells above referred to are the inner inter- 

 stitial ceils (PI. 7, fig. 13, I. I.e.) or inner ganglionic cells of 

 other authors, "and from them arise two fibres, one of which 

 runs to the edge of the retina and the other to the pseudo 

 " sieve-nienibrane,^' following the course of the median 

 supporting cells of Hyde and lying between them. These 

 are the afferent and efferent axons. Distally the afferent 

 axon has a dendritic termination, which conies into relation 

 with the upper end of the axial fibre of the rod. Proximally 

 the efferent axon terminates Avith other efferent axons in a 

 common large ganglionic cell. These marginal ganglionic 



