THE EYE OF PECTEN. 89 



cells^ besides conuectliig- up various axons of bipolar cells^ 

 give off fibres Avliicli make up the proximal branch of the 

 optic nerve. This means in short that the sensory structures 

 (the rod-cells) of all other writers are merely median sup- 

 porting cells^ the inner ganglionic cells of Patten and Ilawit;^ 

 (the interstitial supporting cells) are bipolar nerve-cells, and 

 the marginal ganglionic cells of Hyde have not been seen by 

 any other investigators. Patten and others must have mis- 

 taken, adds Hyde, the axons of the bipolar cells for axial 

 fibres in tlie rod-cells ! 



I took some little trouble to see if it were possible for any 

 of these results to be correct, though from a priori reasons, 

 assuming a little of tlie previous work to be satisfactory, it 

 appeared very doubtful. 



In the first place Patten and his successors could not have 

 seen the bipolar cell axon inside a rod-cell, since they all 

 described it as being outside and possible of separation in 

 teased preparations. 



In the second place, the bipolar cell of Hyde has always 

 been described as inultipolar, and hence though two loii"" 

 afferent and efferent axons might have been missed, her 

 predecessors had a better idea of its true shape. Finallv, 

 since rod-cell and rod are in direct continuation it is impos- 

 sible for the axial fi^bre of the latter to become connected with 

 the process of a cell lying between the former. The results 

 are, in fact, impossible. The rod-cell in its general features I 

 have found to be exactly as described by most other writers. 

 The "bipolar cell" is the interstitial supporting cell to be 

 subsequently described, and the rod contains no nucleus at all. 

 The marginal ganglionic cells as described by Hyde do not 

 exist. I must now refer to the axial fibre and the internal 

 structure of the rods. The first idea striking an observer is 

 that the true condition of things is like that described by 

 Schreiner, viz. an axial fibre is present in the rods, but not 

 in the rod-cells. After staining with iron lia3matoxylin, but 

 especially after using Mallory's stain, with Benin's fluid as 

 fixative, traces of a much thinner fibre or fibres are to be seen 



