200 The Philippine Journal of Science 1915 
eration that positives often show something suspicious (baso- 
philic erythrocytes, granules of chromatin, or the like), so that 
the search for parasites in such slides is prolonged beyond the 
average time. In the course of antimalarial work it might be 
necessary to make a malarial survey in the shortest possible 
time. In such a case an experienced worker might limit the 
time devoted to each thick film to three minutes or less and 
obtain results sufficiently accurate for practical purposes. The 
thick films were so spread as to present thicker and thinner 
areas, and both sorts were included in the search. 
Nearly all of the spleen examinations were made by Raquel 
and Guzman, but those of the third examination of Magdalena, 
those of Cagayan Province, and a few others were made by Rosa. 
While as a routine the blood specimens were taken at the same 
time that the spleen examination was made, our records for 
some localities show more spleen examinations than blood ex- 
aminations. In most cases this is due to the fact that the slides 
were unfit for examination, usually because we were unable to 
get at them before the hemoglobin had become too dry to lake 
out well. Many of the cases occurred during our absence in 
Mindoro and when the weather was hot and dry. 
The general result of the malarial survey is given by provinces 
in Table VI, together with some notes on the anopheles survey 
of each locality. Nearly all of the mosquito surveys were done 
by Barber. A large proportion of the localities were visited, 
but it was impracticable to visit all of them in the time at our 
disposal. Some of them, as those in Cagayan Province, would 
require a journey of about three weeks. 
In choosing localities for survey we aimed, first, to include 
localities of various topographical types as far as possible rep- 
resentative of the main centers of population of the Archi- 
pelago; secondly, to survey some localities known to be malarious 
in order to determine why and to what extent the disease is 
prevalent in them. In the Philippines nearly all the population 
is found in towns or villages; few people live in scattered houses; 
so the indexes of towns fairly represent that of the whole popu- 
lation. Where the word ‘town’ is used in this paper it has 
reference to the center of population, and does not include the 
surrounding country. In the case of school children the sur- 
rounding country is in a measure represented by children 
temporarily residing in the town. All dates are 1914 unless 
otherwise stated. 
