X, B,3 Barber et al.: Malaria in the Philippines 225 
of anopheles in this ditch yielded only a few specimens of A. 
rossi. The parasite and spleen indexes of Calamba were 0. 
Lucban and Sariaya show rather low parasite indexes and 
somewhat higher spleen rates. Each town has many ditches 
containing clear flowing water, which in the case of Lucban, 
especially, are plentiful throughout the streets. Both towns 
are hilly, and the water runs swiftly in most parts of the 
ditches, but there are many possible breeding places for ano- 
pheles. In the survey made of these towns January 7 and 8, 
1915, a few larve of A. febrifer were found in a ditch in a 
street of Sariaya, but considerable search failed to disclose any 
in the ditches of Lucban, although a few were found in a brook 
flowing through the town. Possibly the season of the year may 
in part account for the fewness of anopheles and the low para- 
site rate of these towns. Both towns are in a mountain region 
and rather high (Sariaya, 195 meters above the sea and Lucban, - 
425 meters), and the climate is comparatively cool. We were 
informed at Lucban that the worst fever months there are May, 
June, and July. We do not have sufficient data to indicate 
whether mountain towns of moderate elevations have malarial 
rates much different from towns of lower elevations. Antipolo 
(Table VI, No. 25), with an elevation of from 180 to 190 me- 
_ ters above the sea, shows a lower rate than would be expected 
taking into consideration the number of brooks flowing through 
the town and the number of A. febrifer and of A. maculatus 
breeding in them. On the other hand, Majayjay, Laguna, with 
an altitude of 275 meters shows high parasite and spleen rates. 
Repeated examinations at different seasons of the year would 
probably throw some light on these apparent exceptions. How- 
ever, taken as a group, the high parasite and spleen indexes of 
these towns, situated in immediate contact with A. febrifer 
breeding places, points to a decided relationship of this species 
to the transmission of malaria. 
The number and distribution of malaria cases and the number 
and location of the ditches in the town of Magdalena are given 
on the map (Plate Il). The data of a single survey appear on 
the map, the examination of late October and early Novem- 
ber, 1914 (Table VI, No. 10). The blood specimens were col- 
lected and the cases located on the map by Rosa, and the slides 
were examined by Barber. Children of all ages were taken, 
many of them in a house-to-house canvass. It is evident that 
both breeding places and cases are uniformly and abundantly 
distributed. 
133057——4 
