852 H. M. BERNARD. 



through the outer reticular layer (cf. fig-. 27 d of this paper), 

 and, in the other, the trail of a nucleus that has become a 

 rod-nucleus and has just protruded a cone. 



In individual cases in which extra-nuclear networks are 

 very strongly developed from one side, the wall or membrane 

 of the nucleus on that side appears not infrequently as if it 

 were dissolving (fig. 27 c) . I have, indeed, seen a case in 

 Avhich a whole nucleus appeared to have lost its usually 

 pronounced outline, and to be opening out (fig. 27 e)} 



It will be seen from the figures that these extra-nuclear 

 networks were quite free of any granular cytoplasm. But 

 the fact above stated that, like the granular cytoplasm, they 

 are most frequently found with ganglionic nuclei, compels us 

 to associate them in some way with the cytoplasm. It may 

 be that they usually underlie the masses of cytoplasm which, 

 when present, would render them, as a rule, quite invisible. 

 Traces of a reticular arrangement of the "Nissl's Schollen'^are 

 sometimes visible (see figs. 1 and 12). They are certainly 

 not always present when the nuclei are naked, that is devoid 

 of granular cytoplasm, and it is only in such cases that they 

 can readily be seen in their true form and extent. It would 

 seem that the " Fadengerust " may be at onetime a reticulum 

 and at another a system of rays. 



Returning now to the difficulties which beset the migration 

 of the nuclei through the protomitomic system of which they 

 form the nodes, it would be easy if the whole reticulum 

 moved forward together, but the evidence seems to point 

 to individual nuclei moving not only radially but tan- 

 gentially (from the rim inwards) among the other nuclei. 

 It is possible that this apparent freedom is not really 

 great. Our sections are only snapshots of the process ; 

 hence we may see what appears to be a free movement, but is 

 really controlled by the rest of the reticulum. 



' The opening out of a compact central nuclear reticulum into a more open 

 protomitomic reticulum evenly diatributed throut^liout I lie cell might possil)ly 

 account for tiu; disappearance of the nucleus in red blood-corpuscles; cf. 

 Negri, 'Anat. Anz.,' xvi (1899), p. 33. 



