42 fournal of Comparative Neurology and Psychology. 



which has diffused out of the nucleus. This hypothesis is 

 favored by examining the adult nerve cell which has been 

 stained either by toluidin blue and erythrosin or by Heiden- 

 hain's iron haematoxylin, followed by orange G. These stains 

 show minute particles densely packed around the nucleus ; 

 especially at its two poles. This appearance is shown in figure 

 8, which has been drawn from one of the adult ventral horn 

 cells stained with iron haematoxylin. As is shown in the figure, 

 densely packed rninute granules appear around the nucleus. 

 Some of the granules stain a deep black, while the rest of the 

 granules are tinged grey. Now if we apply the test for phos- 

 phorus and iron to such a preparation, the peripheral layer of 

 the nucleus just within the membrane is found packed with 

 a large amount of the dissolved nuclein, as is shown in figure 

 7, but is not shown in figure 8. From these figures we con- 

 clude that the dissolved nuclein which does not take up either 

 toluidin blue or iron-haematoxylin has been modified into a 

 stainable form on passing from nucleus. This change is due 

 perhaps partly to the accumulation of the minute granules into 

 comparatively larger granules and partly to a chemical trans- 

 formation of the dissolved nuclein into the true Nissl granules. 

 Scott ('99) was able to distinguish three different kinds of the 

 nuclein compounds in the nerve cells ; Nissl granules, baso- 

 phile granules or covering substance of the oxy-center or the 

 central mass of the nucleolus, and oxychromatin. According 

 to him, these three nucleins were derived from the mitotic chro- 

 matin of the primitive nerve cells (germ-cells). It must be 

 kept in mind that all substances in the body are undergoing 

 constant metabolic change. Further, the Nissl granules in- 

 crease in proportion as the oxychromatin increases with the 

 growth of the cell body. This means that a new formation of 

 the Nissl granules takes place within the cell body constantly ; 

 that is, katabolic and anabolic processes are going on incessant- 

 ly. The play of these two processes within the cell body is 

 beautifully described by Max. Verworn ('99). He says "The 

 cell receives certain substances from the outside ; of these some 

 (a) upon meeting substances already present in the protoplasm. 



