SUNIER: Marine fish-ponds of Batavia. 2, 
breeding-place “it is necessary not only to carry out the investigation 
qualitatively, but to do so quantitatively as well”. Now to work quantitat- 
ively it is necessary to adopt a unit in which to express the wealth in 
Anopheline larvae (and pupae) of a given breeding-place. The unit with 
which SCHÜFFNER and SWELLENGREBEL (5!) wish to work is a catch-unit. 
It is their notion to determine the number of Anopheline larvae (and 
pupae), captured in a breeding-place by the method indicated by them (5!) 
on page 53, getting the larvae (and pupae) caught for a definite time and 
equally over an area of a definite size, by a definite number of catchers, 
if possible always by the same men, by means of white enamelled plates, 
white enamelled rice-spoons and empty quinine bottles. It is however 
evident that this quantitative method can hardly be carried out efficiently 
unless by trained catchers and under the strict and constant supervision 
of some person who is perfectly aware of the meaning and the object 
of the process. ') 
But even when such supervision is possible and the catchers are 
well-trained, it still remains a question with me in how far the numbers 
of Anopheline-larvae and pupae, captured after this method in let us say 
a pond in which the larvae-catching coolies are obliged to wade through 
the water and the muddy pond-bottom and on a field on which there are 
footprints of buffaloes filled with water, can afford a basis for comparative 
study. Indeed SCHÜFFNER and SWELLENGREBEL (5') themselves say that 
the quantitative method proposed by them “is a very rough one and neces- 
“sitates a wide margin for errors”. 
Only one attempt at applying this quantitative method is mentioned 
in the Netherlands East Indian malaria-literature'). In their article “On the 
“conditions required by different Anophelines for the dwelling-places of 
“their larvae” (Over de eischen die verschillende Anophelinen stellen aan de 
woonplaatsen hunner larven)?), SWELLENGREBEL and Mrs. SWELLENGREBEL- 
DE GRAAF (®) say: “The method we applied to obtain however 
“imperfect a quantitative, and not a merely qualitative insight into the 
“numbers of Anopheline larvae of each species to be captured, has already 
“been communicated by us before (SCHUFFNER and SWELLENGREBEL, 
“Guide for the Epidemiological Malaria-research (Handleiding voor het 
“Fpidemiologisch Malaria-onderzoek), Weltevreden 1918)”. 
However, further on in the article referred to (°°) no attempt is made 
anywhere to express the catches of larvae in the quantitative catch-unit 
expounded by SCHÜFFNER and SWELLENGREBEL (°!). On the contrary, 
Bi Alter this chapter had been written I saw in Sumatra (Penjabungan, Tapanuli) 
how the exceedingly well-trained native staff of Prof. Dr. W. A. P. SCHÜFFNER, in 
whose company I had the privilege to travel, were able to collect adequate quantitative 
data by the method in question. 
2) Of this article as of other publications of the Netherlands East Indian Civil 
Medical Service, not only the original Dutch text but also an English translation has 
been published. I however prefer to use our own English translation of the passages 
from SWELLENGREBEL’s (°°) original Dutch text quoted here. 
