270 



SANITARY NOTES 



Necessity for 

 ilrainage 



Ankylos- 

 tomiasis and 

 bilharziosis 



justifiable to conclude that the methods of cultivation employed in those districts are crude 

 and unscientific. 



" A principle of scientific cultivation is the preservation of subsoil moisture by the 

 prevention of surface evaporation. The method necessitates the rejjular use of the 

 cultivator or acme-harrow after rain or irrigation so that the land is left covered with 

 a thick and even mulch of loose soil. 



" Dr. Spencer speaks of holes and irregularities present in ' cultivated ' soil. There are 

 no such breeding-places of anopheles in land which has been cultivated scientifically; 

 the beautifully even mulch abolishes them. If the agriculture of the districts referred to 

 were conducted on scientific lines it would not have been possible for Dr. Spencer to 

 trace so ably a distinct connection between the incidence of malaria and the vicinity of 

 ' cultivated ' land. 



" A second lesson is made evident by these facts. With the extension of maize and 

 fruit growing, it is possible that irrigation will be introduced into those dry districts where 

 malaria has not prevailed, solely owing to the lack of breeding-places for anopheles. 

 Beginners in the practice of irrigation — I speak out of past experience— are apt to forget 

 that such crops as maize and fruit under irrigation require also adequate drainage. 

 Stagnant pools and even a water-logged soil may eventually be caused by irrigation when 

 proper cultivation is not carried out or when drainage is not provided : especially if, as is 

 frequently the case, the irrigation shows trop de zHe on the part of the farmer. Thus the 

 anopheline may conceivably be introduced into new districts in the wake of extended 

 agriculture. Where the nature of the crop — as in the case of sugar-cane — requires the 

 permanent presence of flumes, trenches and canals, efficient anti-malaria measures are 

 necessary, such as attention to the construction of the canals, careful removal of the 

 weeds, frequent flushing and stocking with fish which consume the larvae and pupae and 

 eggs of anopheles. 



" The conclusion may be suggested that education in the suitable methods of malaria- 

 prevention should go hand-in-hand with education in scientific agriculture in this country." 



With these statements I am in complete accord, and the problem is more difficult in 

 the Sudan solely because hitherto many of our farmers have been amateurs rather than 

 experts, and were, perhaps, better at raising mosquitoes for the annoyance and to the 

 danger of their fellows, than the crops required for their sustenance and benefit. 



Influence of Cultivation on Other Diseases 



In our First Review Supplement attention was directed to the danger of both 

 ankylostomiasis and bilharziosis increasing in the Sudan as more and more land was 

 brought under cultivation by irrigation methods and as Egyptian fellaheen entered the 

 country in greater numbers to play the role of cultivators. The matter was brought 

 before the Central Economic Board and, so far as medical inspection of immigrants can 

 check the danger, it is likely that all will be well, but the risk to individual health and 

 national prosperity from such operations, on a large scale, should ever be borne in mind, 

 although, just as in the case of anti-malarial measures in their connection with 

 agriculture, it must ever be a question of "Is the game worth the candle?" 



As regards the mosquito work, generally, one need not say much. We are about to 

 test the emulsion-forming larvicide introduced for the great anti-malarial work at Panama. 



It will be used in river pools and other likely breeding-places of this type. A point 

 noted by Mr. Murray, our chief Sanitary Inspector, and worthy of mention, is, that pools 

 with clay bottoms are nmch more favoured by anophclines than those with sandy beds. 



