344 H. M. BERNARD. 



Martin Woodward, to whom I sliowed it. I now naturally 

 connect the plienoinenoii with the streaming process, bub 

 exactly how I do not yet know. There does not appear to be 

 any clear envelope of fluid rouud them as there is round the 

 refractive globules above mentioned, even though they may 

 be much larger in size. Another difference to be noted is that 

 the refractive globules are always perfectly smooth and usually 

 spherical, whereas these are not. They are probably com- 

 parable with the extra-nuclear masses described above, pages 

 338 and 339, and shown in figs. 18 a and h, which are also 

 never surrounded by fluid envelopes or films. 



We gather from the foregoing that the chromatin is a less 

 stable constituent of the retina than the protomitomic system. 

 On the other hand, we know that chromatin is necessary to 

 the life of the cell. And so certainly is the protomitomic 

 system, for I shall be able to show lower down that this system 

 is not a mere passive framework, but that its filaments appear 

 to take an active part in vital processes. We apparently, 

 then, have at least two visible factors in protoplasm, both of 

 which may be regarded as essential: the underljang, more or 

 less stable protomitomic filaments, and the chromatin, the 

 visible distribution of which shows it either stored in the 

 nuclei or travelling along the aforesaid filaments; but what 

 the character of the association between them is has to be 

 discovered. This is but another form of the old problem of 

 the relationship and the relative importance of the nucleus 

 and the astral body, the former representing the chromatin 

 and the latter the protomitomic s^^stem. 



On the Movement of Fluid through the Retina, 

 and on some Phases of the Nuclei probably 

 correlated with this Movement. 



Parallel and probably intimately associated with the stream 

 of chromatin just described as passing outward through tlie 

 retina, there is a steady flow of fluid. The chromatin 

 travelled, as we saw, along the fibrils of the protomitomic 



