468 MONTGOMERY. [Vol. XV. 



within the nucleus would show that dissolution commences 

 in the nucleus ; and we must assume that when the nuclear 

 membrane has disappeared the cytoplasmic substances which 

 then come into contact with the nucleolus would cause its 

 rapid and total dissolution. It may be remarked that in the 

 region of the fully formed spindle (Fig. 311) no trace of the 

 red-stained nuclear sap is longer to be seen ; accordingly this 

 sap with its contained nucleolar substance must either have 

 been distributed through the cytoplasm or have been chem- 

 ically changed by that portion of the latter which immediately 

 surrounds the spindle. 



In the ovary no ova are to be found which have advanced 

 beyond the production of the first pole body, so that the forma- 

 tion of the second pole body must occur after the egg has been 

 discharged from the ovary ; I had no material at hand to enable 

 me to determine the relation of the nucleolar substance in the 

 female pronucleus. 



Of considerable morphological interest are the metamor- 

 phoses of the chromatin in the various ovarial stages. In those 

 small ovogonic mitoses (Fig. 300) from which the true egg cells 

 (first ovocytes) are derived aster and dyaster stages are to be 

 found ; with the lens used for this study (the homogeneous 

 immersion J^ of Zeiss) I could not determine the form of the 

 chromosomes. As the ovum increases in size the dense chro- 

 matin mass of the aster gradually loosens, until up to the time 

 v/hen the nuclear sap commences to stain red (Figs. 301-304) 

 the chromatin is arranged in the form of rather numerous 

 granules, which are situated mostly close to the nuclear mem- 

 brane. Thus far the chromatin has stained intensely blue, with 

 the double stain haematoxylin and eosin ; but when the nuclear 

 sap begins to stain with eosin a marked change takes place in 

 the character and arrangement of the chromatin ; it now stains 

 a lilac color, often more reddish than bluish, and has no longer 

 a peripheral position, but becomes arranged in the form of 

 threads, sometimes in the form of a small number of loops, the 

 two ends of each loop being joined together (Figs. 304, 305, 

 307, 309). In some of the larger germinal vesicles absolutely 

 no trace of chromatin can be found (Fig. 316). In the equator 



