TYPHOID FEVER IN DISTRICT OF COLUMBIA. 
43 
AGE. 
The following table gives the ages of the cases arranged according 
to sex. The youngest case was 8^ months and the oldest 68 years. 
By decades 140 of the cases were under 10 years, 278 between 10 and 
20 years, 259 between 20 and 30 years, 118 between 30 and 40 years, 
47 between 40 and 50 years, and 24 over 50 years. 
Age, sex, and number of cases. 
Years. 
0- 4 inclusive 
5- 9 inclusive 
10-14 inclusive 
15-19 inclusive 
20-24 inclusive 
25-29 inclusive 
30-34 inclusive 
35-39 inclusive 
40-44 inclusive 
45-49 inclusive 
50-54 inclusive 
55-59 inclusive 
60-64 inclusive 
65-69 inclusive 
Total . . . 
Male. 
Female. 
Total. 
19 
13 
32 
53 
55 
108 
75 
56 
131 
82 
65 
147 
79 
64 
143 
57 
59 
116 
41 
34 
75 
21 
22 
43 
13 
11 
24 
15 
8 
23 
5 
5 
10 
5 
5 
10 
0 
0 
0 
1 
3 
4 
466 
400 
866 
IMPORTED CASES. 
In determining whether the infection in a given case was con- 
tracted in or out of the District of Columbia, the whereabouts of the 
person during the thirty days prior to the onset of the first symptoms 
were considered and the incubation period of the disease recognized 
as being about from eight to twenty-five days. In many instances 
where persons spent a part of this time out of the District it was not 
possible to determine positively whether the infection was contracted 
in or out of the District, and therefore the cases were considered 
under the following heads: 
Cases. 
(а) Infection undoubtedly contracted out of the District of Columbia 80 
(б) Infection probably contracted out of the District of Columbia 32 
(c) Infection contracted in or out of the District of Columbia (chances about 
equal) 34 
(d) Infection probably contracted in the District of Columbia 32 
(e) Infection undoubtedly contracted in the District of Columbia 681 
(/) No information regarding whereabouts obtainable • 7 
Total 866 
As the number who actuallv contracted the infection out of the 
c/ 
District can not be determined with absolute accuracy, the fairest 
