318 H. M. BERNARD. 



any rate bound to assume that the filaments find their way 

 through, because nuclear filaments certainly plunge into the 

 inner reticular layer from both sides (cf. figs. 14, 15, 17 c, and 

 18 d, with figs. 6, 7, 8, 10, 11). Since those which leave the 

 nuclei laterally on each side run directly into adjacent 

 nuclei, there can hardly be a doubt that those which plunge 

 into the inner reticular layer on the oue side are on their way 

 to meet those entering the layer from the other side. 



Keviewing the foregoing paragraphs, we see not only that 

 the nuclei of the different nuclear layers are joined together 

 inter se, but that the connecting filaments pass through the 

 intervening reticular layers which separate the retinal nuclei 

 into zones, so that all the nuclei of the retina are 

 connected together into an organic system. I say 

 an organic system because the evidence shows that the 

 connecting threads are continuations of those which form 

 the basis of the intra-nuclear reticulum. They are not mere 

 suspensory fibrils, for which I first mistook them, but true 

 extensions of the nuclear framework. 



Summary of the Cy tological Results sofar obtained. 



The retina, then, reveals to us a continuous nuclear system 

 underlying its whole structure as a reticulum, whose filaments 

 are achromatic and so fine as to be visible only with the best 

 optical appliances, and then only when they are not obscured 

 by cytoplasmic elements; — the syncytial framework and the 

 masses of granular cytoplasm which envelop some of the 

 nuclei. Their presence may, however, be revealed at any 

 time during phases of physiological activity when they are 

 coated with other substances. This "protomitomic" reticulum 

 is so distributed throughout the retina that the nuclei which 

 are themselves reticular are its nodes. All the other con- 

 stituents of the retina, the various forms of cytoplasm 

 outside the nuclei, and even the varied substances within the 

 nuclei, have to be regarded in their relations to this under- 

 lying protomitomic system. 



