What is Being Done in

East Indies.

THE following is part of an article, “Malaria in the Netherlands Is lands”, by N. H. Swellengrebel, pub lished in a new quarterly magazine, “The Bulletin of the Colonial Institute” (63 Mauritskade, Amsterdam, Holland). It is an excellent compilation, produced by the Netherlands Pacific Institute, and dealing especially with the problems of the Netherlands Indies.

THE system of malaria-transmission is highly vulnerable because of its specialisation, for it is delegated, not to all mosquitoes, but to a special tribe, the anopheles, and among this tribe, to only a small number of species. So all man has to do is to destroy those ex perts in malaria-transmission. All other anopheles he simply ignores.

That is the reason why we see the department of malaria-control in the Netherlands Indies bent on knowing the species of anopheles they are dealing

with, and on finding out the ways and means to destroy the harmful species without having to go to the expense of killing all anopheles. The staff of this department has been blamed for being interested in entomology. One might as well find fault with an artillery-offi cer for being interested in mathematics!

There was a time, however, in the early twenties, when we thought we were all wrong in our dealings with the indivi dual species of anopheles. Facts were gradually accumulating to show that one and the same anopheline species may be

a dangerous carrier of malaria in one country and perfectly harmless in an other. The anopheles ludlowi, which is such a deadly carrier in the Netherlands Indies, can always be safely ignored in the Philippines and very often so in Malaya.

This is very serious. If we cannot count on our species of anopheles always behaving in the way we have learned to expect, how can we base our plan of ac tion on the assumption that they, and no other anopheles, carry malaria? I well remember, at that time, one of our stud ents protesting at being taught to identify the various species of Netherlands Indian anopheles, on the plea of its being a perfectly useless effort, as we should very soon be reverting to the old method of killing all anopheles (which really means killing none, as a fight sustained against all anopheles is much too costly).

At present, some sixteen years after that crisis, “species control”, i.e., the method of dealing with malaria by an ac tion directed against one species of ano pheles to the exclusion of all others, stands on a firmer basis than it ever did before.

This has been brought about by the concerted action of investigators in the department of malaria-control of the Netherlands Indies and in the two In stitutes of Tropical Hygiene, at Amster

dam and Leyden, each group of workers proceeding along its own lines, all of which, however, led to the same result, that can be briefly stated as follows. The principle of species control remains un shaken, but some of the so-called ano pheline species which had revealed them selves as dangerous malaria-carriers in one country and as harmless mosquitoes m another, were proved to be groups of two or more species, very much resembling each other in shape and design, but differing in their habits to such an extent as to render one an efficient malaria-car rier and another quite harmless.

It was a long way to go to obtain a result which can be stated in words so few as hardly to exceed, in number, the years it took to establish it. But the result was worth the trouble, first and foremost because it fully restored our con fidence in species control, and secondly, because it afforded an interesting exam ple of very effective, although quite un premeditated, collaboration between inves tigators in the Far East with those at home.

So the basis of malaria-control in the Netherlands Indies is sound and the re sults obtained are striking, as testified by the interest workers from neighbouring countries are taking in it. But these results are few and far apart, compared with all that still remains to be done.

Malaria remains a major scourge to the natives of those parts. It is to be hoped that improving economic condi tions will remove some of the obstacles which prevent that magnificent institu tion, the department of malaria-control in the Netherlands Indies, from display ing its activity unhampered.