MOSQUITO WORK IN KHAKTOUM AND IN THE ANGLO-EGVPTIAN SUDAN GENEEALLY 19 



the desert zone (for the grassy region does not begin for at least 150 miles farther to the 

 south), there can appear no necessary reason why it should be more unhealthy than either 

 Shendy or Berber ; all that is wanted is that the sanitary authorities shouhl exercise a better 

 management and see that stagnant pu(klles should be prevented. As I have ah-eady 

 intimated I found that, during my absence, not a few of my former acquaintances had fallen 

 victims to the fatal climate." How suggestive are these passages ! In those days the role 

 of the mosquito in malaria was unknown. It was not the stinking and evaporating puddles 

 which were to blame, though they may have played a subsidiary part, but the Anophelines 

 bred out in them. 



That Schweinfurth's friends died of malaria there can, I think, be little doubt, and I 

 regret to say that given a wet summer, and it is said comparatively wet summers may 

 occur in Khartoum, there is nothing to prevent a similar state of matters arising at the 

 present time. Khartoum has been rebuilt, and much has been done to render it a healthy 

 city, but there has not yet been time to have its site properly levelled or drained. Because 

 of recent years the seasons have been dry it has not been necessary to cope seriously Danger of 

 with flooding by heavy rains. There are no surface drains, the centre of the town pon^'in^^" 

 lies in a hollow ; there are many depressions. That pools readily form and may persist for 

 a long time I have myself observed. In October, 1905, very heavy rain fell for about an hour 

 and a half, amounting in all to 1'8 inches. The pools formed by it persisted in some cases 

 for from twelve to sixteen days and finally had to be emptied by a fire pump. Fig. 6, 

 paijr 20. Under favourable circumstances Pi/ri'tojj/ionin costal !■■< will jiass through all its 

 water stages in a little over a week. 



What is to occur if we get repeated showers of torrential tropic rain distributed 

 throughout several months ? I have no hesitation in saying that malaria would occur 

 and possibly run riot. Our little mosijnito brigade could never cope with the 

 conditions, special working parties would fail to get rid of all the water in time, the 

 amount of oil necessary would be enormous, and it would be blown into heaps at the ends 

 of the pools. Anophelines would invade us from without and the sickness rate would certainly 

 rise. Observe the statistics given ! It is always after rain that more mosquitoes are found. 

 In part this is due to the fact that the rain often washes away the soil from under the edges "°" "^'" ^'^'■^ 

 of the well covers, leaving holes whereby mosquitoes can gain entrance, while it also causes 

 old wells to fall in. and water collecting at the foot of them, forms very favourite breeding 

 places. Anophelines, however, rarely breed in wells, and they are very fond of pools and 

 puddles. The remedy is obvious. Although it may appear to some that I am merely 

 advocating a waste of money, I believe that Khartoum should either be drained or the 

 levels improved. At present efficient drainage would be best. No one can say when a 

 comparatively wet summer may deluge the town. The Blue Nile can be kept out, the rain 

 cannot, but it can be removed, and provision for its removal should be made. The town 

 is to be given a water supply, and when this is an accomplished fact better provision will 

 have to be made for the disposal of slops and waste waters. Whatever scheme be chosen 

 it might be adapted to deal at the same time with storm waters though admittedly the 

 problem is a somewhat difficult one owing to the lack of fall in certain directions.* While 

 discussing this subject one may consider whence the invading Anophelines come and how 

 they reach Khartoum. I believe they are usually bred out in the pools which form in 



* It is satisfactory to note that this question is now uudcr discussion and schemes for dealing both with 

 storm-waters and waste-waters are being considered. 



