428 EIOHAED EVANS. 



passing out of the nucleus through the nuclear membrane, 

 which may occasionally, so to speak, heal up again. In 

 such cases, though the chromatin has been cast out of the 

 nucleus to form the small nuclei, a kind of skeleton of the old 

 nucleus is often seen to accompany the smaller ones in the 

 incompletely divided mass of cytoplasm (fig. 5 b). The cell 

 marked d' is a peculiar one, not often seen, and had I not 

 been quite familiar with mitotic figures I might possibly have 

 made the mistake of explaining it as a stage in mitotic divi- 

 sion. But the great number of the granules is a sufficient 

 reason for rejecting such a view. It is far more probable that 

 it is a cell in which the chromatin of the nucleus has become 

 aggregated into granules before the nuclear membrane gave 

 way for its extrusion. The stage represented in the cell d 

 passes gradually into that illustrated in e, in which the chro- 

 matin appears in the form of small and spherical bodies which 

 display no structure whatever, and which are distributed 

 throughout the cell, the nuclear membrane having disappeared. 

 By a gradual transition the condition found in the cell e passes 

 to that represented in f, in which the chromatin bodies show 

 a certain amount of structure. The fig. g represents a still 

 later stage, in which the chromatin bodies have grown con- 

 siderably, and are not very diflFerent from the nuclei of the cell 

 groups illustrated in fig. 9 a. If the group of small nuclei 

 represented in fig. 40 g be compared with that in fig. 9 a, and 

 the one represented in fig. 40 g' with fig. 9 b, the resemblance 

 in all their characters will be found to be a most striking one. 

 The additional fact that the figs. 40 g and g' represent the 

 same cell in successive sections, and the figures of the '' cell 

 group " in 9 a and b do the same, increases the importance of 

 the resemblance between them, and the only conclusion pos- 

 sible is that the one becomes the other, and that the changes 

 above described prove the nuclei of the cell groups to have 

 originated from the vesicular nuclei by fragmentation. 



Since the cell groups are produced in the way described, it 

 follows that they must be considered as a category of cells 

 quite apart from the cells with granular nuclei. Though they 



