CHANGES ]N CHOx\ DEIOSO.M ES. 
565 
the nodular junctions of the fibrils passing between adjacent 
cells are still recognisable. 
Tlie appearance of the prickle layer of the epidermis when 
undergoing active proliferation is shown in fig. 11. The 
epidermal fibrils are seen to be arranged in bundles or 
sheath-like collections which pass from cell to cell. Within 
the cells the fibrils can be traced through the cytoplasm; 
they do not enter the nucleus, though frequently lying near 
the nuclear membrane as the figure illustrates. Although 
many of the fibrils entering the cell can be seen to pass out of 
the cell again, nevertheless the exact distribution of the 
fibrils in the ])rickle-layer is comple.x and. difficult to follow 
out in its entirety. At the junction of the fibrils of adjacent 
cells a variable degree of thickening occurs, spindle-like 
nodules being thereby produced. When a number of such 
nodules are seen on the fiat in optical section, as is shown in 
sevei'al cells in the upper half of fig. 11, a remarkable prickly 
or hirsute appearance is pi-esented. The fibrils are of nearly 
uniform thickness throughout their course in the cell pro- 
toplasm. 
The extent to which chondriosomes are altered in conditions 
involving active cell proliferation cannot be estimated with 
great precision owing to the impossibility of satisfactorily 
exhibiting the chondriosomes of the epidermis in perfectly 
healthy skin, for the methods of fixation and staining at 
present available usually reveal only the nodular thickenings 
at the points of junction of the fibrils of apposed cells, the 
fibrils themselves eitlier remaining unstained — and this is the 
usual event — or staining imperfectly. As has been already 
mentioned, onr knowledge of epidermal fibrils has been for 
the must part obtained by the study of the epidermis in 
pathological conditions. Judging by the appearance of the 
nodular junctions, it would seem that the chondriosomes in 
conditions of epithelial proliferation are markedly hyper- 
trophied. "WTiether in addition any increase in the number 
of the fibrils or any change in their distribution in the cell 
protoplasm also occurs cannot at present be determined. 
