Structure and Polarity of Electric Motor Nerve-Cell in Torpedoes. 227 



call the karyosomes or chromatin nucleoli. These bodies have been 

 mentioned by Garten (17 B) and others, and have been more carefully 

 and particularly described by Magini in connection with a new sub- 

 stance which he calls perichromatin, in a paper published by him at 

 Montepulciano in 1901 (24 D). My results do not in any way conflict 

 with the morphological facts brought out in this excellent paper, but 

 I believe that in Magini's work and in mine the chemistry of several 

 of the bodies described is not sufficiently understood to designate any 

 one of the three of them as the same substance as the chromatin which 

 goes into the chromosomes of embryonic tissue cells that are dividing 

 by mitosis. This chromatin is surely to be found among these bodies 

 and my separation of them will be a little more close than his was, but 

 histogenetic, experimental physiologic, and chemical work will be nec- 

 essary for a sufficient understanding of the subject. Only in failing to 

 distinguish chemically (by color) between his "filimento nucleinico a 

 gomitolo" or "rete cromatica" or "granuli cromatici" and his masses 

 of perichromatin, do I find myself differing, and I still hope to find 

 some true or basichromatin disposed in this way with other staining 

 methods. 



These chromatin nucleoli are rather larger and more abundant than 

 Magini states in his paper. The largest one measured in my prepara- 

 tions was fully 2^ microns in diameter and many could be found that 

 measured 1| to 1| microns. Many also are found below 1 micron in 

 size, although these very small ones do not seem to grade down to an 

 excessively small granule. 



In the fresh state the chromatin nucleoli are visible and appear to 

 possess a fairly high index of refraction, although not quite so high as 

 that of the plasmosome. They are colorless and motionless and appear 

 to be quite equally distributed through the nucleus. The larger ones 

 are farther apart than the smaller. Some are placed directly against 

 the nuclear wall and others at various points in the nuclear space. 

 One of them is sometimes found against the side of the plasmosome. 



In a considerable number of cases these bodies are grouped together; 

 that is, instead of one being found at a single central point, two or more 

 will appear, closely placed and apparently acting as a unit in the 

 arrangement that has been mentioned. When so grouped, the super- 

 numerary granules are usually very small, although sometimes two 

 large ones will be found acting together. 



These spherules or chromatin nucleoli are homogeneous and are 

 about the most easily stained bodies in the nucleus. Their staining 

 powers differentiate them at once from any other nuclear content. 

 Particularly good to show the chemical difference in staining are some 

 of the bulk stains, as a double staining with paracarmine and hemalum 

 or borax-carmine and hemalum. In either of these two, with strong 

 decolorization, the chromatin nucleoli take a deep, bright, transparent 



