392 MOA'TGOMERY. [Vol. XV. 



Jodgriin tingirten Schnitten werden die Paranucleolen weder 

 reinroth wie die Nucleolen, noch blaugriin vvie die chromatische 

 Substanz gefarbt, vielmehr nehmen sie eine Zwischennuance, 

 welche mehr der des Chromatins als der der Nucleolen ahnelt, 

 an"; he believes these paranucleoli to be artefacts. In con- 

 tradiction to Karsten ('93) he found no body in Psilotiim 

 comparable to a Nucleo-Centrosoma. 



Zacharias ('94) concludes, from numerous observations on 

 cells of plants that as the size of the nucleus increases (or 

 decreases) with the size of the cell, so also that of the nucleolus 

 increases (or decreases) vi^ith the size of the nucleus. 



In Rosen's ('95) contribution a large number of new facts 

 are recorded, which may be briefly mentioned. The kyanophilic 

 nucleoli of Auerbach " sind eben keine Nucleolen und bediirfen 

 als wenig constante Theile des Chromatingeriistes iiberhaupt 

 keines besonderen Namens." Hyaciiithus : in meristem nuclei 

 all the nucleoli except the smallest lie in special clear spaces, 

 and though fibrils are rarely found in connection with them, 

 " gleichwohl muss das Kernkorperchen in seiner scheinbar 

 schwebenden Lage wohlbefestigt sein, da es . . . stets seine 

 Lage im Centrum seines Hofes bewahrt." The large nucleoli 

 of the " Gefasszellen " become vacuolar as they increase in size. 

 In mitosis of root cells the nucleoli become gradually dissolved 

 within the nucleus in some species, in others they are extruded 

 into the cytoplasm; in the latter cases " erfolgte die Zerkliiftung 

 und Auflosung des Nucleolus viel langsamer, sodass bei dem 

 Schwinden der Kernmembrau noch bedeutende Nucleolarreste 

 vorhanden waren." The nucleoli reappear in the dispirem 

 stage before the daughter-nuclei have produced membranes, 

 and the new nucleoli stain from the commencement intensely; 

 from which the general conclusions are drawn : in the prophase 

 the diminishing nucleolar substance penetrates, perhaps as a 

 micellar solution, into the cytoplasm, and this process may 

 cease before the nuclear membrane has disappeared. In some 

 cases larger particles of nucleolar substance may penetrate 

 into the cytoplasm, but only after the nuclear membrane has 

 disappeared, and these particles become subsequently dissolved 

 in the cytoplasm ; in either case " das losende Agens muss wohl 



