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value in the comparative study of such a disease, it being susceptible both 
to diseases peculiar to animals (hemorrhagic septicemia) and to those 
common to man and to animals (amoebic dysentery). This makes the 
animal an ideal one for bridging the gap between the monkey and man 
in the study of the reactions of various mammalian hosts to a given 
disease-producing parasite. We regret that owing to the difficulty of 
acclimating these animals our data are not as abundant as might be 
desired. 
Technique—Two young female orang-utans were inoculated on. the 
skin of the abdomen with variola virus in the same way as were the 
monkeys in the work the details of which have already been described. 
The animals were observed daily and the evolution of the lesion at the 
site of the inoculation and the constitutional reaction was recorded. 
Material for the histological examination of the specific lesions was 
collected. The details of the experiments are as follows: 
No. 197. Young female orang-utan. The animal was first exposed to small- 
pox fomites. The results of this experiment will be considered in another article. 
Twenty-one days after the exposure, the animal was inoculated in 12 places on 
the abdomen with virus No. 252. Forty-eight hours after inoculation there 
was slight elevation about the scratches. The deep pigmentation of the skin 
made it impossible to tell whether or not hyperemia was present. 
Five days. Along each line of inoculation there was a narrow, yellow crust 
seated upon a vague elevation. On gentle pressure turbid fluid exuded from 
beneath the crust. A small amount of this fluid was used to inoculate a Philippine 
monkey on the skin of the abdomen. This animal developed a typical pock at the 
site of inoculation and subsequently a profuse general exanthem. 
‘Six days. The primary lesions were somewhat more prominent and the whole 
of the area beneath them was indurated. Axillary lymph nodes enlarged, firm 
and tender. 
Seven days. The animal had scratched the lesions and they presented shallow 
ulcerations with ragged and often bleeding edges. The subcutaneous edema had 
increased in extent, causing a brawny induration over the whole field of inoculation. 
The animal died during the night of an intercurrent infection. 
No. 198. Young female orang-utan. Inoculated in 12 places on the skin of the 
abdomen with virus No. 199. After 24 hours slight elevation was apparent along 
the lines of inoculation. Body temperature 36°.1 C. 
Four days. A narrow crust marked the scratch and was bordered by a distinet 
elevation. No change of color could be distinguished on account of the deep 
pigmentation of the skin. Body temperature 35°.9 C. 
Five days. The elevation of the lesions had increased and they had become 
circumscribed. Body temperature 36°.6 C. 
Six days. The zone of elevation was distinctly vesicular near the crust and 
clear serum oozed out on gentle pressure. Body temperature 36° C, 
Seven days. Lesions had increased somewhat in extent and the crust had spread. 
Body temperature 35°.7 C. 
Kight days. Animal found dead in cage early in the morning. Rigor mortis 
present, body still warm. Autopsy at once. Skin.—The inoculation sites present 
crusts, about which is a shallow cavity filled with turbid fluid. This vesicle 
appears to lie between the true skin and the epidermis. The border of the lesion 
shows some thickening of the skin, but this is not nearly so marked as at a corre- 
