B59 
With the progressive cell changes in the epidermis, exudation becomes 
an important factor in the typical process. Fluid finds its way into the 
degenerated epithelium and separates the degenerating cells so as to form 
spaces filled with fluid. In this manner the formation of the vesicle is 
begun. That the exudate sometimes breaks into hollow cells is proved by 
the occasional presence of free nuclei in the smaller chambers. The 
exudate may at this early stage appear perfectly clear or it may contain 
a smal] amount of fibrin either in the form of a reticulum or of a granular 
precipitate. 
The continuous escape of the exudate into the epidermis rapidly dilates 
the smaller chambers into a large vesicle. In case the lesion has 
developed from multiple centers, the various chambers are separated by 
septa and trabecule which are prone to rupture on account of the rapidity 
of exudation. ‘The chamber begins to form in the middle layer of the 
epidermis so that a portion of the stratum spinosum is lifted up with the 
horny layer to form the roof, while the floor of the vesicle is at this stage 
wholly or partially covered with epithelial cells. 
At the sides of the vesicle and in the trabecule, the cells become 
elongated and stretched through the pressure of the exudate. With the 
cells thus stretched, the epithelial fibers of Herxheimer become prominent. 
It seems evident that there is an actual production of fibers coincident 
with the swelling and stretching of the cells. They appear as straight 
fibers, with tapering ends, extending lengthwise over the surface of the 
epithelial cells. In some cases the cells become torn from their original 
attachment and the fibers then released take on a spiral or crinkly form. 
(Pl. I, fig. 10.) They vary much in thickness and where cells lie free 
in the vesicle contents they often extend directly into the cell and 
terminate against the nucleus. 
Lying free in the vesicle contents or in groups over the floor of the 
vesicle and along the trabeculz are epithelial cells showing various forms 
and stages of degeneration, prominent among which are the large multi- 
nucleated cells resulting from the so-called “ballooning degeneration.” 
These cells now present further degenerative changes. The protoplasm 
is often condensed into a membrane about the nucleus or the group of 
nuclei. External to this membrane the cytoplasm is very soft in ap- 
pearance, being composed of a delicate reticulum. In this delicate por- 
tion, deeply stained granules or masses appear. On the surface of such 
cells there are sometimes globular or elongated masses staining faint 
blue, which radiate from the cell like the petals of a flower. In many 
cases the uniformity of these bodies and their arrangement is suggestive 
of some sort of an organism. After studying a number of cells of this 
type, the observer is convinced that the masses are pseudopodia-like pro- 
jections from the soft protoplasm or portions of it which have been 
constricted off. In some cells the so-called “acidophilic” or “fibrinoid” 
degeneration has become marked and the entire protoplasm appears 
