┌────────────┬───────────────────────────┬──────────────────────────┐ │ │ ATTACK RATE UNDER │ ATTACK RATE OVER │ │ │ 10 YEARS OF AGE. │ 10 YEARS OF AGE. │ │ ├───────────┬───────────────┼───────────┬──────────────┤ │ │VACCINATED.│ UNVACCINATED. │VACCINATED.│ UNVACCINATED.│ ├────────────┼───────────┼───────────────┼───────────┼──────────────┤ │_Dewsbury_ │ 10·2 │ 50·8 │ 27·7 │ 53·4 │ │_Leicester_ │ 2·5 │ 35·3 │ 22·2 │ 47·6 │ │_Gloucester_│ 8·8 │ 46·3 │ 32·2 │ 50·0 │ └────────────┴───────────┴───────────────┴───────────┴──────────────┘ =Severity (Fatality) among Vaccinated.=—The experience of the same three towns comes out as follows:— ┌────────────┬───────────────────────────┬──────────────────────────┐ │ │ ATTACK RATE UNDER │ ATTACK RATE OVER │ │ │ 10 YEARS OF AGE. │ 10 YEARS OF AGE. │ │ ├───────────┬───────────────┼───────────┬──────────────┤ │ │VACCINATED.│ UNVACCINATED. │VACCINATED.│ UNVACCINATED.│ ├────────────┼───────────┼───────────────┼───────────┼──────────────┤ │_Dewsbury_ │ 2·2 │ 32·1 │ 2.6 │ 18·7 │ │_Leicester_ │ 0.0 │ 14·0 │ 1.0 │ 7·8 │ │_Gloucester_│ 3·8 │ 41·0 │ 10·0 │ 39·7 │ └────────────┴───────────┴───────────────┴───────────┴──────────────┘ In view of such results as the above it is not surprising that the Royal Commission, in their majority report, summed up the advantages of vaccination as follows: “(1) That it diminishes the liability to be attacked by the disease. “(2) That it modifies the character of the disease, and renders it (_a_) less fatal, and (_b_) of a milder or less severe type. “(3) That the protection it affords against attacks of the disease is greatest during the years immediately succeeding the operation of vaccination. It is impossible to fix with precision the length of this period of highest protection. Though not in all cases the same, if a period is to be fixed, it might, we think, fairly be said to cover in general a period of nine or ten years. “(4) That after the lapse of the period of highest protective potency, the efficacy of vaccination to protect against attack rapidly diminishes, but that it is still considerable in the next quinquennium, and possibly never altogether ceases. “(5) That its power to modify the character of the disease is also greatest in the period in which its power to protect from attack is greatest, but that its power thus to modify the disease does not diminish as rapidly as its protective influence against attacks, and its efficacy during the later periods of life to modify the disease is still very considerable.