Multiplication and Migration of Nucleoli in Nerve Cells of Mammals 209 



DESCRIPTION OF PLATES. 



Fig. 1. Cell from Gasserian ganglion of a rabbit, .showing an early .stage in the 

 Ijudding of the nucleolus, and some chromatin aggregates upon the membrane of 

 the nucleolus. 



Fig. 2. Ditto. 



Fig. 3, A cell from the same ganglion, in which a bud has travelled some 

 distance from the nucleolus, but is still attached to it. 



Fig. 4. Ditto. 



Fig. 5. Ditto. 



Fig. 6. A cell from the same ganglion, in which the attacliraent of the bud to 

 the nucleolus is broken. 



Fig. 7. A cell showing the same phenomenon, with several buds separated oft' 

 from the nucleolus. 



Fig. 8. A cell from the same ganglion, showing several nucleoli. 



Fig. 9. A rare mode of nucleolar division. 



Fig. 10. A cell from the same ganglion, showing a nucleolus that has been 

 pushed out of the nucleus by the action of the microtome knife. There is an empty 

 space in the nucleus, and the nuclear membrane shows no signs of being regenerated. 

 Here the staining reaction of the nucleolus is the same as in the case of nucleoli 

 contained in the nucleus. 



Fig. 11. A cell from a spinal ganglion of a cat, showing the nucleolus pressing 

 out the nuclear membrane. 



Fig. 12. A cell from the same ganglion, showing the nucleolus passing through 

 the nuclear membrane. Here the staining reaction of the nucleolus is changing. 



Fig. 13. A cell from the same ganglion, wdiich shows the appearance, in optical 

 section, of the crater formation of the protrusions of the nuclear membrane described 

 in the text. The nuclear membrane has re-formed behind the nucleolus. 



Fig. 14. A cell from the same ganglion, in which the extruded nucleolus is 

 adherent to the nuclear membrane. The nucleolus has increased considerably in 

 size, and has become definitely granular. Here its staining reaction is quite diff'erent 

 from what it is in the case of the nucleoli still contained in the nucleus. 



Fig. 15. Ditto. 



Fig. 16. An extruded nucleolus still adjacent to the nuclear membrane 

 (spinal ganglion of cat). 



Figs. 17, 18, and 19. Nucleoli passing towards the periphery of the cell after 

 being extruded from the nucleus (spinal ganglion of cat). The pseudopodial 

 processes of the nucleus are interpreted as being the remnants of the protrusions 

 produced by the passage of the nucleolus. 



Fig. 20. A nucleolus passing bodily out of a nerve cell (spinal ganglion of cat). 



Figs. 21 and 22. The contents of nucleoli being taken from the nerve cells into 

 the cytoplasm of adjacent cells (spinal ganglion of cat). 



Fig. 23. A nucleolus derived from a nerve cell in the cylojilasm of a capsular cell. 



Fig. 24. A nucleolus derived from a nerve cell surrounded by leucocytes. 



