1 88 Journal of Comparative Naavlogy a fid Psychology. 



with the hnin net. The part of the linin net which enters into the 

 radiating bands contains granules which stain a darker red than the 

 other acidophile elements and black with iron haematoxylin. In the 

 radiating bands beyond the limits of the nucleus there occur granules 

 which stain black also in iron haematoxylin but dark blue in toluidin- 

 erythrosin. They are sharply differentiated from the tigroid elements 

 by their reaction to Delafield's haematoxylin and the triacid stain. 

 In the former they stain blue-black, while the tigroid elements stain 

 faint blue ; in the latter, they appear green while the tigroid elements 

 appear red. This reaction places them in the category of basichro- 

 matin and they must be considered as such elements which have mi- 

 grated out from the nucleus. They become basophile during their 

 migration from the nucleus and represent the nuclear chromatin. 



While these changes are going on the nucleus enlarges and mi- 

 grates towards the periphery of the cell, till, in some cases, a mere 

 film of protoplasm separates it from the cell membrane. In the mean- 

 time, also, the acidophile granules of the nucleus have increased 

 greatly in number and during the process also the nucleolus sends off 

 fragments into the cytoplasm. 



KoLSTER ('oo) also contributes interesting facts upon the general 

 morphology of the nucleus. In a large series of preparations he finds 

 that only a part of the nuclear border has a regular outline and limit- 

 ing membrane. As studied in serial sections the nuclei, practically 

 without exception, lose their membrane in a particular region and the 

 karyoplasm pushes out in pseudopodia-like processes into the cytoplasm. 

 This appears to the author to be a constant feature and not due to any 

 peculiar physiological condition. He interprets it as concerned in the 

 nutrition of the nucleus. But, compared with Holmgren's work, 

 Kolster's results are noteworthy from the fact that the side of the nu- 

 cleus which is marked by this irregular contour may lie opposite the 

 centrosome while Holmgren finds it directed toward the centrosome. 



Irregularities in the border of the nucleus have been observed 

 also by Bochenek ('oi) in certain large nerve cells of Helix. 



The idea that the nuclear membrane breaks down and that there 

 is an interchange of formed substance between the nucleus and the 

 cytoplasm, especially as described by Holmgren, is opposed by 

 Scott ('99). He believes this appearance is due to the action of the 

 knife in cutting. However, it hardly seems probable that both Holm- 

 gren and Kolster should be utterly deceived in this manner. More- 

 over, it does not seem that Scott's fundamental thesis or his results 



