Structure and Division of the Vegetable Cell. 205 



iodine solution, when looked at with a power of 300°, is 

 granular ; consisting of clear spots, not distinguishable 

 optically from the nuclear membrane ; and of intervening 

 parts more deeply stained ; but when magnified 450°, these 

 appearances are seen to be due to the presence of an inter- 

 lacing network (intranuclear network of Klein), the meshes 

 of which are filled by the more deeply stained " ground 

 substance." One can further notice the fibres stretching 

 inwards from the inner nuclear membrane with which 

 they seem to fuse ; while from the outer surface of the 

 nucleolus like processes pass outwards. Professor Ruther- 

 ford, who has thoroughly examined the nuclei of animal 

 cells, confirms the preceding observation. But even 

 though unable to demonstrate directly the existence of 

 an intranuclear network, the behaviour of the nuclei and 

 nuclear contents would lead to such a conclusion ; for in 

 nuclei which have been isolated, torn, and split asunder, 

 the nucleolus may protrude prominently without any indi- 

 cation of passively separating ; shreds of the intranuclear 

 network are also encountered adhering to the nuclear 

 membrane. Now, even although the nuclear substance 

 is hardened by the decolorising or staining agent, this 

 hardening could not alone account for conditions such as 

 have been mentioned ; I therefore strongly incline to the 

 opinion that the filaments of the intranuclear network 

 stretch inward from the inner layer of the nuclear mem- 

 brane, and are finally attached to the outer surface of the 

 nucleolus, thus holding the latter in position. Further 

 proof of this will be adduced in studying the division of 

 the cells. 



The nucleolus of Binrogyra is very large, and is a 

 morphological entity, not in any way to be confounded 

 with a local thickening of the intranuclear network. A 

 nucleolar membrane, quite as evident, but scarcely equal 

 in width to that of the nucleus, surrounds it. With the 

 outer surface of this the nuclear fibres seem to fuse. Its 

 inner surface is smooth, and does not show that it gives off 

 processes into the interior. Instead of having a granular 

 or reticulated aspect like the nucleus, it gives the impres- 

 sion that it is a pretty homogeneous body. 



The nucleolo-nucleus, as before mentioned, is sometimes 



