CONDITION OF EPIDERMAL FIBRILS IN EPITHELIOMA. 293 
The first step in this process is that the fibrils become 
arranged more closely together, i.e. not traversing each cell 
in all directions, but in compact bundles. In this condition 
they lie very close to the nuclear membrane (fig*. 1, d, and 
fig. 2). This is followed by some of the fibrils becoming 
greatly thickened, being at least twice their ordinary diameter 
(fig. 1 ,d and fig. 2). This is a gradual process, and does not 
affect all the fibrils in a bundle simultaneously (fig. \,d). At 
the same time that this thickening takes place the fibrils also 
become shorter, or perhaps contract, so that they no longer 
traverse two or more cells, but lie wholly within the limits of 
one cell, closely entwined round the nucleus (figs. 2 and 3). 
In fig. 3 it will be seen that this change is far advanced; no 
fibrils pass from the affected cell to four of the adjacent cells, 
and from the three other cells which lie in contact with it 
the few remaining* fibrils are being withdrawn. 
The thickening of the fibrils continues till at last a mantle 
of thick fibres surrounds the nucleus. The latter may lie 
centrally (fig. 4 and fig. 5, e) or eccentrically (fig. 5 f and h) 
to the mantle. Eventually the fibrils are so swollen and 
pressed together that they fuse, and form a homogeneous 
covering round the nucleus or its remains, in which only 
traces of the individual fibrils retaining their identity can be 
seen (fig. 4 and fig. 5, h). 
As might be expected, while these changes are taking 
place in the fibril bundles the nucleus is also affected. The 
unaffected cell contains a nucleus which is large in proportion 
to the cytoplasm. Such a nucleus has a well-defined mem- 
brane, one or more nucleoli, and a scanty linin network, on 
which are distributed some granules of chromatin (fig. 1, 
a, b , c, d). But in those cells in which the epidermal fibrils 
degenerate, the nucleus undergoes changes which take the 
following course. 
The nucleoli break up into several fragments (fig. 3 and 
fig. 5, f and li), the linin threads become indistinct, and the 
chromatin granules together with the nuclear remains lose 
their affinity for the luematoxylin stain. Eventually, the 
