STUDIES IN THE RETINA. 323 



salivary glands; Arnold ^ and others claimed to have seen 

 nerve-fibrils ending in the chromatin granules suspended 

 on the intra-nuclear networks in unstriped muscle-cells, while 

 a whole host of workers discovered connections between 

 threads coming from the nucleoli of s^niipathetic ganglion- 

 cells and their nerves.^ I attribute the fact that these have 

 never been confirmed, in spite of the special searches which 

 have been made for them, mainly, judging from my own 

 experience, to the accidents of fixation, but also to the dis- 

 credit cast on them by the improbable nature of other 

 phenomena described at the same time ; these latter, how- 

 ever, as I shall show elsewhere, need not at all involve the 

 existence of the filainents. Lastly, Haycraft^ described 

 nerves ending in the nuclei of epithelial cells in the tortoise. 



I mention these in passing to show that the claim that the 

 nerve-fibrils are in organic connection Avith the intra-nuclear 

 network is not new. No one, however, has hitherto been 

 able to establish it ; even the same worker has at times 

 failed to confirm his earlier observations; the reasons for this 

 the opening pages of this paper should make clear. There 

 can, I think, be little doubt but that, had Max Schullze 

 lived,* the confirmation would have been forthcoming, — that is, 

 if we may judge from his method of describing the fine 

 structure of the nerve-fibres in Strieker's ' Lehre von den 

 Geweben ' in 1871. After having written that, he could 

 never have rested until he had discovered what became of the 

 primitive uerve-fibrillae which coiLipose the axis-cylinder after 

 they had entered the cell. 



The discovery of the protomitomic system answers the 

 question. The primitive nerve-fibrillre of the retinal 

 nerve-strands are continuous with the filaments of 

 the retinal protomitomic system. 



1 Strieker's 'Leiire von den Geweben,' vol.i (1871), p. 142, fi^. 33. 



- For a historical review, see, for example, ' Anatoniie des Nervensystems,' 

 ii (1876), p. 130, by Key and Retzius, who tliemselves failed to find any con- 

 tinuations of the intra-nuclear reticulum beyond the nuclear membrane. 



' ' Quarterly Journal of Microscopical Science,' vol. xxxi (1890), p. 563. 



* He died in 1874, at the early age of 49. 



