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on the twenty-first day of the experiment. In every animal a typical vaccine 
lesion developed at the site of inoculation. 
(e) Variolation of the skin after variolation of the mucous membrane of the 
palate-—Three monkeys were selected that had shown a typical variolous lesion 
on the soft palate after inoculation with virus No. 307. Eighteen days after the 
initial inoculation the animals were variolated on the abdomen with virus 
No. 307. ‘Two of the monkeys showed no reaction to the skin inoculation, while 1 
yielded a typical primary lesion, but no exanthem developed. 
(f) Vaccination of the skin after variolation of the mucous membrane of the 
lip and nose.—One monkey was inoculated in this way. Typical variolous lesions 
developed on the inner side of the lip and on the nasal septum after inoculation 
with variola virus No. 167 (vesicle contents). The monkey was vaccinated on 
the abdomen with virus No. 148 and No. 1 on the seventeenth and forty-first day 8, 
respectively. No lesion developed after either vaccination. 
(g) Vaccination on the skin of the temple after vaccination of the abdomen.— 
Two monkeys that had shown a typical vaccine lesion on the abdomen were later 
shown to be refractory to vaccination on the temple. 
SUMMARY. 
(a) A vaccine lesion of the skin protects against. subsequent inocula- 
tion of the cornea with vaccine virus, but the protection is not complete. 
(6) A variola lesion of the skin does not protect against subsequent 
inoculation of the cornea with variola virus. 
(c) In one monkey a variola lesion on the cornea protected against 
subsequent inoculation of the skin with variola virus. 
(d) A variola lesion on the mucous membrane of the palate does not 
protect against subsequent inoculation of the skin with vaccine virus. 
(e) A variola lesion on the mucous membrane of the palate does not 
completely protect against subsequent inoculation of the skin with variola 
virus. 
(f) A variola lesion on the mucous membrane of the lip and nose 
protected, in one instance, against subsequent inoculation of the skin 
with vaccine virus. 
(g) A vaccine lesion on the skin of the abdomen protected against 
subsequent inoculation of the skin of the temple with vaccine virus. 
DISCUSSION. 
The summary of our experiments in this section demonstrates that 
the immunity produced by a variolation on the mucous membrane is lower 
than that produced by a variolation on the skin. 
We have already shown that the immunity produced by a variolation 
on the skin is lower than that following a vaccination on the skin, and 
we find that this is emphasized by the results of inoculations of the 
cornea after vaccination and variolation of the skin. The fact that 
even vaccination of the skin does not completely protect against sub- 
sequent corneal inoculation with vaccine virus illustrates our point with 
regard to the quantitative relation of the two immunities. 
