32 
GEOGRAPHICAL DISTRIBUTION. 
Maps 2, 3, 4, 5, 6, 7, and 8 show the distribution of the cases by 
place of residence when the infection was considered to have been 
contracted. 
Again this year, as in 1907 and 1906, the distribution was quite 
general; but there was in 1908 a noticeable concentration of cases in 
certain sections. 
The marked grouping of cases in the Georgeto\\Ti section of the 
city, which occurred in September and October, was due to a milk 
outbreak which was confined largely to that section. 
Smaller groups of cases, attributed largely to contact infection, 
may be noted on the maps in south Washington, in Twining City, 
and in Ivy City. These smaller groups are in sections where the 
general sanitary conditions are poorer than they are in the greater 
part of the city. 
Apart from the local grouping of cases, there appeared to be in the 
southern sections of Washington as a whole a higher prevalence of 
typhoid fever due to causes undetermined than in the northern 
sections. In fact, a general survey of the distribution of the cases 
gives the impression that typhoid fever in Washington is caused by 
factors some of which operate generally and scatter infection broad- 
cast over the city, while others operate locally and cause the small 
groups of cases observed to occur in certain sections. 
Map No. 8 shows the distribution of cases by place of residence in 
the 53 vital statistical districts of the District of Columbia. 
The following table gives the population and the number of cases 
of typhoid fever which developed from May 1 to November 1, 1908, 
in each of the vital statistical districts : 
Table No. 5. — Shovjing population and incidence of typhoid fever in each vital statistical 
district in the District of Columbia. 
Vital statistical 
districts. 
Population. 
Number of cases of typhoid fever devel- 
oping from May 1 to November 1, 
1908. 
1 
t 
' Case rate 
per 10,000 
j of popu- 
lation. 
White. 
Colored. 
1 Total. 
1 
1 
Unac- 
counted 
for. 
Attrib- 
uted to 
direct 
contact. 
Attrib- 
uted to 
milk in- 
fection. 
Total. 
1 
11,710 
6,105 
17,815 
13 
0 
i 
1 1 
14 
1 
' 7.8 
2 
6,392 
4,994 
11,386 
9 
0 
2 
i 9-6 
3 
7,638 
3,416 
11,054 
21 
2 
1 
24 
21.6 
4 
663 
2,108 
2,771 
1 
0 
1 
2 
7.2 
5 
10,276 
8,697 
18,973 
15 
4 
0 
19 
10.1 
6 
15,487 
3,285 
18,772 
10 
0 
0 
10 
5.3 
7 
9,522 
978 
10,500 
12 
2 
0 
14 
13.3 
8 
14,884 
2,626 
17,510 
32 
4 
0 
36 
20.5 
9 
13,192 
11,872 
25,064 j 
29 
2 
0 
31 
12.3 
10 
13,397 
4,034 
17,431 : 
17 
3 
0 
20 
11.4 
