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lymphatics and blood vessels, and a marked polynuclear leucocyte infiltra- 
tion. 
Both cytoplasmic and nuclear phases of cytoryctes variole are present 
in the epithelial cells. In one lesion, of 5 days’ duration, an endothelial 
cell was found on the wall of a lymphatic, just beneath the epithelium, 
which contained a cytoplasmic form of the parasite. 
Palate—The histology of the primary lesion in this situation is similar 
to that seen in the lesion on the lip. A lymphatic with cytoplasmic 
forms of cytoryctes in the endothelial cells lining its wall was found 
beneath a lesion of 5 days’ duration. 
Histological examination of the viscera showed no lesions. The bone 
marrow and testicles were carefully examined for focal lesions, such as 
are found in these organs in varivla vera in man, but none could be 
demonstrated. 
DISCUSSION. 
The disease produced by variolation of the monkey upon the mucous 
membrane of the lip, nose, and palate is characterized by the development 
of a self-limiting lesion at the site of inoculation, which may be followed 
by a general cutaneous exanthem and be associated with an indefinite 
constitutional reaction. 
If we compare the initial lesion produced on the mucous membrane 
with that which follows a similar inoculation on the skin we see that the 
two processes are similar, in that they run a definite course and tend to 
heal after about the same interval of time. The microscopic study of 
these lesions shows them to be the result of similar cell changes, and in 
each the parasite, cytorcyctes variole, is found associated with the process. 
The lesions differ in that on the mucous membrane the absence of crust 
prevents the development of a vesicle or pustule, although an accumula- 
tion of fluid between the cells is in evidence at certain stages of the lesion. 
The primary lesion on the mucous membrane, of 4 or 5 days’ duration, 
simulates closely a skin lesion of the same duration which has lost its 
crust through rough manipulation. The primary lesion on the mucous 
membrane also differs from that upon the skin in that the process in 
the tissue beneath the lesion is more exudative and proliferative than 
necrotic. 
When we compare the other manifestations of the disease following 
variolation of the mucous membrane with that following skin inoculation 
a decided difference is found. We see that a general exanthem is much 
less apt to follow the inoculation of the mucous membrane. Of 19 
animals inoculated in the nose, on the lip, or on the palate only 2 showed 
a general exanthem. In both these animals the lesions of the eruption 
were few in number and required microscopic study for their positive 
diagnosis. The exanthem occurred in a trifle over 10 per cent of the 
animals. This is in sharp contrast with the occurrence of the exanthem 
