1 88 Macfarhnic — Current Problans 



ability of parts may be largely or wholly reversed during 

 division, as do the later studies of Miss Sargant, Farmer, 

 Wager and Dixon. 



Miss Huie's experiments on the feeding of Droscra leaves 

 prove that an intimate relation exists between the nucleus 

 and nucleolus, and that reciprocal chemical changes are con- 

 stantly proceeding in them. While differential stains may 

 often aid us in the demonstration of structural details, they 

 may prove fallacious guides in the interpretatmi of morpho- 

 logical and micro-chemical relations. 



The nuclear membrane is now so universally conceded to be 

 a morphological feature of the resting nucleus that the appli- 

 cation of a definite name is appropriate. Apart from the 

 study of living cells, carefully fixed material alone presents 

 the natural appearances. Alike in living and stained cells it 

 shows striking resemblances to the threads of the nuclear 

 network internally, and to the radiating kinoplasmic threads 

 which traverse the proptoplasm externally. In some plants it 

 is evidently continuous with the latter. But where imperfect 

 fixation has been effected, the membrane often resolves itself 

 into a system of threads and knots, in no way different from 

 the nuclear network. This may be even characteristic of 

 living cells, as we shall have occasion to mention later, and 

 has caused Wisselingh to describe the membrane as made up 

 of " small bodies, lumps and granules." Its behavior 

 when fresh cells of Spirogyra nitida are simultaneously 

 swollen up and stained by 50 per cent alcoholic eosin is 

 instructive. As osmosis proceeds, the radiating strands 

 from the nucleus snap suddenly along one side, the 

 enveloping protoplasmic mantle of the nucleus then immedi- 

 ately expands on that side, while the nuclear membrane 

 remains as a puckered but continuous envelope. But it is 

 during the dividing state of the cell that we can learn most as 

 to its morphology. In Spirogyra nitida, during the prophase 



