308 H. M. BERNAKD. 



the case in wliicli the granular cytoplasm actually surrounds 

 the nucleus, but does not completely fill a syncytial chamber, 

 an axis-cylinder process is difficult to imagine. It is only 

 iu the comparatively fi'W cases (few, that is, except in the eyes 

 of the higher vertebrates) in which the cytoplasmic matter 

 completely fills the syncytial chamber (cf. fig. 1, and the 

 majority of the drawings in fig. 26), making it turgid, that 

 the diagrammatic axis-cylinder process is possible. But, in 

 such cases, as stated, I have never yet, iu the whole course of 

 my study of the retina, succeeded in finding it, although the 

 distal ramifications from the same cells, when there are any, 

 are always quite distinct. 



This is apparently the experience of at least some other 

 Avorkers also. For example, Birch-Hirschfeld ^ has recently 

 published a paper with careful drawings of sections of 

 retinas showing ganglionic cells, but none with the diagram- 

 matic axis-cylinder processes. On the other hand, Borysie- 

 kiewitz figures such processes in the typical manner. And 

 here let me say that there is nothing in the account here to be 

 given of the nerve connections which precludes the possibility 

 of the existence of such processes; indeed, it is a m.atter of 

 surprise that they do not appear to occur. I am only stating 

 the fact that, during ten years' continuous work on many 

 retinas, 1 have never seen anything like the diagrammatic 

 axis-cylinder process, though, at one time, I looked dili- 

 gently for it. I am therefore justified in concluding that 

 when it occurs it is of the nature of an accidental variation 

 upon the ordinaiy mode of connecting the nerve with the 

 ganglionic cell which will be described below. 



Further, the description of the "ganglionic cells" as 

 nuclei, with which granular cytoplasmic matter may or may 

 not be associated, applies to all the ''cells" of the retina. 

 It is well known, for instance, that the nuclei of the middle 

 nuclear layer have, as a rule, no cons})icuous masses of cyto- 

 ])]iism. A few very large " cells," closely resembling the 



' 'Arch. OiihU:.,' 1 (I'jni), p. IGC; cf. also AbcUdorf's figures iu Die 

 ' Arcli. Augciilieilk.,' xlii, p. ISS. 



