mollgaard's reticulum 331 



reticular arrangement. Though this description applies particu- 

 larly to smears frozen at —5° to — 10°C., it also applies in part 

 to smears frozen at temperatures as low as — 25°C. 



d. Nerve cells of smear's frozen at —10°C. and lower. The 

 changes next in occurrence to those described under the heading 

 just preceding are to be observed in cells of smears frozen at 

 — 10° to— 25°C. In such preparations some of the cells show 

 many of the Nissl's bodies still appearing as individual networks 

 but with larger meshes and more closely interconnected, all how- 

 ever being still confined within the cell wall (fig. 4). In the 

 cellular cytoplasm no changes are yet to be noticed. The nuclear 

 chromatin (and also the achromatic substance of the nucleus 

 which stains pink with erythrosin) has become distinctly reticu- 

 lar, apparently forming one continuous network limited to the 

 area within the nuclear membrane; or, extending beyond the 

 nuclear membrane and becoming continuous with the blue-stain- 

 ing network derived from the Nissl's bodies. The nucleolus may 

 be unaffected, or may take part irt the formation of the nuclear 

 chromatin reticulum, forming as it were its starting point by 

 sending out a varying number of processes. Some nerve cells 

 show these changes much intensified with the cellular cytoplasm, 

 exclusive of Nissl's bodies, also becoming reticular. This cyto- 

 plasmic reticulum, although continuous with the blue-staining 

 network, is readily distinguished, when once fully formed, by 

 the fact that it stains pink with the counterstain employed. In 

 general, too, this pink-staining cytoplasmic reticulum has smaller 

 meshes than the blue-staining network, and lies within the inter- 

 stices of the latter. In order to avoid confusion, only the blue- 

 staining portion of the reticulum is shown in the figures. Still 

 other cells at this temperature (— 25°C.) and at lower temper- 

 atures (—25° to — 50°C.) show a reticulum with much larger 

 meshes. The elements composing this reticulum are none other 

 than those already mentioned, namely, the blue-staining network 

 derived from the Nissl's bodies, nuclear chromatin, and nucleolus; 

 and, the pink-staining network derived from the cellular cyto- 

 plasm (exclusive of Nissl's bodies) and the achromatic substance 

 of the nucleus. The continuity of these two networks is one of 



