Or, considering only the 542 cases, of which 438 undoubtedly and 
104 probably contracted the infection in the District of Columbia, 
we have — 
1908 (May 1 to i 
November 1). ! 
1907 (May 1 to 
November 1). 
1906 (June 1 to 
November 1). 
Cases. 
Percent- 
ages. 
Cases. 
Percent- 
ages. 
Cases. 
Percent- 
ages. 
Infection attributed to milk 
52 
9.59 
i 
1 48 
9. 18 
85 
11. 30 
Infection attributed to contact 
114 
21. 03 
102 
19. 50 
54 
7.30 
Accounted for 
166 
30. 62 
150 
28.68 
139 
18.60 
Unaccounted for 
376 
69. 38 
i 373 
71. 32 
608 
81. 40 
Total 
542 
100. 00 
523 
100. 00 
747 
100. 00 
Prevalence . — In 1907 and 1908 the typhoid fever rate in the District 
of Columbia was lower than that of any other year of which there is 
record. The reduced rate for both these years as compared with that 
of 1906 was accounted for by the reduction in the number of cases 
occurring in the summer periods. 
Diagnosis . — Practically every case of clinical typhoid fever in 
Washington is reported to the health officer. Some cases not typhoid 
fever are reported as such. The official records, therefore, show 
more typhoid fever than exists in a clinical sense. 
There should be official confirmation of the diagnosis of all cases of 
typhoid fever and of all cases suspected to be typhoid fever. This 
would greatly aid in the suppression of the disease. 
Race . — During the warm season the disease prevails proportion- 
ately among white and colored. In the cold weather, however, the 
disease prevails proportionately more heavily among the whites. 
Sex . — The disease is somewhat more prevalent among males, espe- 
cially among those between the ages of 15 and 34 years. 
Age . — The disease in 1908 again was especially prevalent among 
children, suggesting that milk and contact are responsible for more 
cases than can be definitely traced to these factors. 
Endemicity . — The majority of cases occur among persons who 
have not been absent from Washington within the thirty days pre- 
vious to onset of illness, and moreover among those who have lived 
in Washington all their lives, showing that Washington is a true 
endemic” center. 
■Seasonal 'prevalence . — In 1906 and 1908 the typhoid season and 
the summer season were both early. In 1907 there were a cool spring 
and late summer, also a belated typhoid curve, showing strikingly 
the correlation between the beginning of summer weather and the 
increased prevalence of the disease. 
