LB, 8 Barber et al.: Malaria in the Philippines 195 
DISTRIBUTION OF MALARIA IN VARIOUS PROVINCES, 
TOWNS, AND BARRIOS 
In determining the malarial index of a locality, both the para- 
site and the spleen indexes were taken, in a large proportion of 
cases by the examination of school children, the majority of 
whom were from 5 to 10 years of age. No intentional selection 
of well or sick children was made. The examinations were made 
during school hours of children in attendance on that day. The 
examination of school children entails two disadvantages. First, 
the children who are seriously ill are less likely to be in at- 
tendance, so there was some selection of those less likely to be 
malarious. However, as numerous cases showed, children often 
return to school very soon after their illness, and since com- 
paratively little systematic quinine treatment is practiced in 
Filipino towns, children recently recovered from malaria are 
likely to show parasites. Therefore the error through selection 
of the well is not great. Secondly, the parasite rate is usually 
higher in children from 1 to 5 years of age than in older children 
(see Magdalena, Table VI), and since few children below 5 
years of age attend school, our percentage would be somewhat 
lower than for all young children. Neither source of error, how- 
ever, affects the value of our statistics in the comparison of 
different localities. Moreover it is improbable that any con- 
siderable amount of indigenous malaria can exist in a locality 
without some cases appearing among children from 6 to 10 
years of age. Since our aim was primarily to ascertain the 
distribution of malaria, the advantage of quickly obtaining 
specimens from a large number of children in schools would out- 
weigh the disadvantages of this method. 
In some cases examinations were made of children, taken in 
part at least, out of school or of older persons. These cases are 
indicated in the tables. ; 
‘Blood for examination for parasites was taken from the ear, 
and as a rule, but one slide was taken of each person at a 
visit. A thick smear and a thin smear were made on the same 
slide. The blood was dried in the air, then the slide was care- 
fully wrapped in a piece of paper on which were recorded the 
data of the case: namely, name of person, age, sex, result of 
spleen examination, and history of recent illness. The wrapped 
slides were closely fitted into pasteboard boxes, and the boxes 
were inclosed in paper and sent as quickly as possible to the 
laboratory. These precautions were taken in order to minimize 
dangers from moisture or overdrying, according to the season, 
