A CRITICAL REVIEW OF THE LITERATURE ON EXPERI- 
MENTAL VARIOLA AND VACCINIA IN THE MONKEY. 
The literature bearing upon the reactions of the monkey to inoculation 
with the virus of vaccinia or of variola is to be found in fifteen publica- 
tions, which are briefly summarized below. These articles will first be 
considered separately in chronological order and the findings will then be 
combined so as to present a connected account of our present knowledge 
of the subject : 
Zulzer, 1874, attempted to produce variola in “Cercopithecus.” This author 
describes briefly the results of experiments on 5 monkeys. Two animals were fed 
with a mixture of bread and variolous material. No disease followed this pro- 
cedure, The hair was clipped from an area on the back of one monkey, care being 
taken not to injure the skin, and variola virus was put in contact with the skin, 
where it was allowed to remain for three hours. The animal showed no reaction. 
One monkey was inoculated on the skin with blood from a case of hemorrhagic 
variola, This monkey showed a rise in the body temperature which ranged 
between 40.8° and 41.4° C. from the sixth to the eleventh day of the experiment. 
A profuse general exanthem developed. One monkey was given dried variola virus 
to play with and in this animal the same phenomena was seen as in the animal 
inoculated with the variolous blood. 
Buist, 1887, records certain experiments which are only of value in that they 
showed the susceptibility of the monkey to variola and to vaccinia. 
Copeman, 1894, reports a rather extensive series of inoculations of “Rhasus”’ 
monkeys with variola virus and with 2 sorts of vaccine virus. He found them 
susceptible to all 3 viruses and also found that each virus protected against a 
second inoculation with the others. Two monkeys inoculated subcutaneously with 
vaccine virus were later shown to be immune to skin inoculation with the same 
virus. One monkey received an intraperitoneal injection of oxalated plasma from 
a monkey which had been rendered immune to vaccinia and to variola by inocula- 
tion. This animal was vaccinated 14 days later and it was noted that the lesions 
did not develop as well as upon a control monkey inoculated at the same time 
with the same vaccine virus. This author finds that the acme of the lesion at the 
site of inoculation is on the eighth day, both when vaccine and when variola virus 
is used. Vesiculation is not so marked in the pock resulting from variolation as 
in that following vaccination. A general exanthem was noted in some of the 
monkeys after inoculation with variola virus. These monkeys also showed consti- 
tutional reaction to the inoculation, as was evidenced by fever, diarrhea, suffusion 
of the eyes, and some malaise. The temperature reaction was more marked in 
them than in the monkeys inoculated with vaccine virus. 
In 1895 Sternberg reported the results of experiments by Reed in immunizing 
monkeys against vaccine with the serum of vaccinated calves and monkeys. Cer- 
copithecus mona, “Rhesus,” and Cobus apella were employed. In two instances 
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