318 
Smallpox and Vaccination 
in which persons are protected by different kinds of vaccination can be judged 
by a comparison of the proportions in each group at the same age period at the 
different epochs. Persons thus of the age five to ten years in 1872 will be fifteen 
to twenty in 1882, and will be thirty-five to forty-five in 1902. These proportions 
are recorded in the accompanying table. From this it may be seen that in general 
after forty years all vaccinated persons ai'e apparently equally liable to smallpox. 
The proportions of persons attacked with smallpox who were from forty to sixty 
in 1872, sixty to eighty in 1892, and above seventy in 1902 with one, two, three, 
and four scars respectively, are sensibly constant considering the small number of 
TABLE IV. 
Table showing the Percentage of Persons attacked by Smallpox, imth the different 
numbers of Vaccinal Cicatrices at each age period, in tlie Epidemics 1870 — 72, 
1880—85, 1892—95, and 1902 in London. 
Group I. Persons 0—10 years, 1870—72. 
EijiJeiuic 
Age Periods 
One Scar 
Two Scars 
Three Scars 
Four Scars 
1870—72 
0—10 
24-6 
25-5 
22-6 
27-3 
1880—85 
10—20 
20-7 
25-7 
31-3 
22-2 
1892 — 95 
20—30 
14-3 
237 
28-3 
35"1 
1902 
30—40 
7-9 
14"2 
24 '8 
51 "1 
Grou]) 
II. Persons 
10—20 years, 
1870—72. 
Epidemic 
Age Periods 
One Scar 
Two Scars 
Three Scars 
Four Scars 
1870—72 
10—20 
22-2 
36-8 
23-3 
17-5 
1880—85 
20—30 
21-3 
32-3 
26-0 
19-9 
1892—95 
30—40 
20 
27-0 
29-0 
23 
1902 
40—50 
18-4 
28-4 
27-1 
25-9 
Group 
III. Persons 
20—30 years, 
1870 -72. 
Epidemic 
Age Periods 
One Scar 
Two Scars 
Tln-ee Scars 
Four Scars 
1870—72 
20—30 
24-6 
39-6 
19-4 
16-7 
1880—85 
30—40 
1892-^-95 
40—50 
28-6 
28-4 
15 
22-8 
1902 
50—60 
16-7 
35-6 
23 
22-5 
Group IV. Persons 
30—40 years, 
1870—72. 
Epidemic 
Age Periods 
One Scar 
Two Scars 
Three Soars 
Four Scars 
1870—72 
30—40 
29-8 
41-6 
17-8 
16-6 
1880—85 
40—50 
1892—95 
50—60 
24-7 
30-3 
21-3 
23-6 
1902 
60—70 
26-4 
31-8 
18-7 
23-1 
Group 
V. Persons 
40—60 years. 
1870—72. 
Epidemic 
Age Periods 
One Scar 
Two Scars 
Three Scars 
Four Scars 
1870—72 
40—60 
32-7 
391 
16-6 
10-4 
1880—85 
50—70 
1892—95 
60—80 
50 
32-3 
5-9 
11-8 
1902 
70— 
39-9 
37-1 
11-2 
11 -2 
