630 
Years, 
14 to 20 
20 to 30 
30 to 40 
40 to 50 
50 to 60 
60 to 70 
70 to 80 
Total 
The Philippine Journal of Science 1921 
TABLE 2.—Age incidence. 
40 
80 
19 
9 
8 
8 
0 
164 
Table 2 shows that the greatest number of cases occurred in 
young adults from 20 to 30 years of age. This observation is 
80 
60 
Age in years. 
10 20 30 40 50 60 70 80 
| 
L 
| 
| 
Cases. 
tS 
> 
20 
0 
Fic. 1. Illustrating the age incidence | 
by decades. 
similar to Shiga’s(9) findings, in 
Japan, who also observed a great 
number of cases between the ages 
of 20 and 30 years. A graphic 
representation of age incidence 
is shown in fig. 1. 
SEASONAL INCIDENCE 
The disease occurs throughout 
the year. In my series it pre- 
vailed in greatest number in 
July, August, and September. 
The incidence is shown in Table 
8 and graphically presented in 
fig. 2. 
TABLE 3.—Seasonal incidence. 
Month. Cases, 
January 3 
February 2 
March 1 
April 8 
May 7 
June 9 
July 39 
August 42 
September 40 
October 8 
November 2 
December 3 
A study of Table 3 indicates that there was a gradual in- 
crease in the number of cases admitted to the hospital from 
April to September, the largest number having occurred during 
