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produced by the two viruses. In this section we will detail experiments 
which bear upon the general problem of the immunity reactions of the 
monkey to vaccine and to variola virus from a somewhat different point 
of view. 
In testing the immunity of rabbits after skin and after corneal inocula- 
tions with vaccine virus, Dr. R. L. Thompson’ obtained results which 
tended to show a difference in the degree of immunity depending on the 
locus chosen for the primary vaccination. As we were more favorably 
situated as regards facilities and animals for experimentation, we decided 
to continue this line of work on monkeys. We have extended the scope 
of the experiments so as to include the study of the relative immunity 
produced by vaccination and variolation of the skin, cornea, and mucous 
membranes. 
EXPERIMENTS. 
(a) Vaccination of the cornea after vaccination of the skin.—This experiment 
was performed upon 5 monkeys (M. cynomolgus). Each animal had shown a 
typical vaccinal lesion on the skin as a result of an inoculation with virus No. I, 
148, 236, or 251, and each was tested 22 days after the first inoculation by vaccina- 
tion of the skin with virus No. 148. The cornea was vaccinated with virus No. 148 
on the twenty-ninth day after the initial skin vaccination. The animals were 
killed after 48 hours, and paraffin sections of the corneas were examined micro- 
scopically. 
Four of the monkeys showed no specific lesion on the cornea. One showed a 
typical vaccinal keratitis with proliferation of the epithelium and the presence of 
numerous cytoryctes. 
(b) Variolation of the cornea after variola inoculata from skin inoculation.— 
This series consisted of 5 monkeys which had shown a typical primary lesion on 
the abdomen following inoculation with variola virus No. 167 (disk). Three of 
these animals had developed a general exanthem. 
On the twenty-fourth day of the experiment each monkey was inoculated on the 
cornea with variola virus No. 167 (vesicle contents). The animals were killed 
after 72 hours and the corneas studied microscopically. Each animal presented 
a typical variolous keratitis at the site of inoculation, and cytoryctes were present 
in large numbers. 
(c) Variolation of the skin after variolous keratitis——This experiment was 
performed on a single animal. The cornea was inoculated with variola virus 
No. 200. A typical lesion developed. Eighteen days after the corneal variolation 
variola virus No. 252 was inoculated on the skin of the abdomen without pro- 
ducing a lesion. The skin inoculation was repeated on the forty-first day with 
variola virus No. 307, and again no reaction followed. 
(d) Vaccination of the skin after variolation of the mucous membrane of the 
palate-—The 5 monkeys employed for this experiment had developed a typical 
variolous lesion on the soft palate, following variolation with virus No. 167 
(vesicle contents). Each animal was vaccinated on the skin with virus No. 148 
™These experiments were carried on in the pathological laboratory of the 
Boston City Hospital under the direction of Dr. W. T. Councilman. Owing to the 
impossibility, at the time, of carrying out the research on extensive enough lines 
to yield definite conclusions, the results were not published. 
