340 If. M. BERNARD. 



the inner reticular layer from the " ganglionic " nuclei. I nm 

 inclined to look to wliat are known as " Nissl's Schollen " 

 within the ganglionic cells for light on this subject. These 

 " SchoUen" maj^ be regarded as consisting of dense crowds of 

 minute masses of chi'omatin (microsomes), whose origin from 

 the nuclei can easily be demonstrated under the microscope 

 by noting not only their usually concentric arrangements 

 round the nuclei (see fig. 26, especially e), but also the relative 

 positions of and connections between the clots and the intra- 

 nuclear masses (see figs. 1 and 26 g, 1-, and m). Further, 

 retinas may be found in which deeply staining clots can be 

 seen adhering closely to the sides of nuclei which have no 

 granular cytoplasm at all (fig. 5), a fact which shows that this 

 latter substance plays no direct part in their production, 

 Avhatever influence its presence may have on their distribu- 

 tion and constitution as clouds of microsomes. Their origin 

 from the nuclei is, indeed, generally admitted. 



All the microscopic appearances suggest most unmistakably 

 that these " SchoUen " are streaming away into the inner 

 reticular layer, together with the granular cytoplasm in which 

 tliey are usually embedded. No one, indeed, can examine 

 " cells " such as those I have attempted to figure (fig. 26) 

 without coming to this conclusion; cf., for instance, the 

 massing of the " Schollen" proximally, and their comparative 

 scarcity distally ; while those which do occur on the distal side 

 are very frequently drawn out into the processes of the cells, 

 down which they thin away to invisibility. These speak for 

 themselves. Here, then, we have evidence that chromatin 

 escapes from the ganglionic nuclei and makes its way with 

 the granular cytoplasm through the inner reticular layer 

 towards the middle layer. In this case, however, Ave do not 

 exactly know whether, in moving outwards, it travels along 

 the protomitoniic filaments, or independently. The former 

 supposition is the more probable, as we shall presentl}^ see. 

 Meantime, what we can justly assume is that it finds its way 

 into the more distal nuclei to replace the chromatin that 

 streams away into the rod-nuclei and ultimately into the rods. 



