351 
but from sporadic cases of varicella. Eimer, who has critically consid- 
ered Hesse’s work, concludes that only one of his cases can be accepted. 
Steiner’s results are, in the two cases which he gives in detail, beyond 
question. He inoculated two children one 4 years old and previously 
vaccinated, the other 2 years and not vaccinated. Neither had had vari- 
cella previous to this time. He inoculated the upper arm with perfectly 
clear lymph from the vesicles of a case he considered to be undoubted vari- 
cella. Four days after the inoculation there was elevation of temperature 
which increased, accompanied by some constitutional disturbance, up to 
the eighth day when a typical varicella eruption appeared. The develop- 
ment of the eruption together with the symptoms he describes in full. 
The parallelism of the two cases as regards time of onset and eruption 
relative to inoculation makes spontaneous infection seem improbable. He 
had previously inoculated eight children with varicella with positive 
results in six, making a total of eight successful inoculations. Of the 
eight cases five had been previously vaccinated, so that it seems improbable 
that he dealt with a mild form of variola. 
The data furnished by d’Heilly’s inoculations are meager. He claims 
to have produced an eruption in two of the cases inoculated, one after 
an incubation of three, the other after an incubation of seventeen days. 
We see by this review that the attempts to produce varicella by 
inoculation show positive results in but few cases and some of these are 
not beyond question. 
The only animal inoculations which I have found recorded are those 
of Freyer (5) and of Park (11). Freyer collected the fluid contents 
of twenty grayish-yellow, clouded vesicles, and ground it in a mortar 
after adding a small amount of glycerin. With this mixture he in- 
oculated a calf without result. The calf was inoculated afterwards 
with vaccine lymph and reacted in a typical manner. Park inoculated 
two monkeys with varicella material with negative results. He points 
out the diagnostic value of this proceeding and cites a case in which 
it was used. 
The only account of the histological changes in the skin lesions in 
varicella is that of Unna (18) (19). He takes up the changes occurring 
in the epidermis in the development of the vesicle and describes two 
types of cell degeneration which he designates “reticulating colliquation” 
and “ballooning” degeneration. His description of these may briefly be 
summarized as follows: 
1. Reticulating colliquation affects chiefly the older cells of the epider- 
mis; that is, the stratum spinosum and outer layers. The cells increase 
in size and in stained sections appear pale. This swelling may be 
followed either by a partial or total solution of the interior of the cell. 
The cell membrane, however, persists so that large cellular cavities are 
formed. If the softening of the interior of the cell is partial a coarse 
reticulum will be found, but if the softening’ is more complete the cell 
a et 
